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Journal articles on the topic 'Clamping Units'
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1
JACHOWICZ, TOMASZ. "Construction of clamping units of injection molding machines." Polimery 50, no. 02 (February 2005): 110–17. http://dx.doi.org/10.14314/polimery.2005.110.
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Zhang, Pan Pan, Peng Cheng Xie, Dai Hua, and Wei Min Yang. "Experimental Study on Mold Separations of Plastic Injection Molding Machines with Different Clamping Units." Advanced Materials Research 87-88 (December 2009): 64–68. http://dx.doi.org/10.4028/www.scientific.net/amr.87-88.64.
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The plastic injection molding is widely used for the manufacturing of complicated-shaped and high value-added products. The plastic injection molding machine is the most important equipment for the industry. This paper focuses on the mold separation (MS) of the injection molding machines. The characteristics of the MS of injection molding machine with different clamping units are systemically analyzed, the five-hinge joint-double toggle clamping unit and the direct hydraulic pressure clamping unit included. The study points out there are several typical differences between the different clamping units. Meanwhile, it shows there is a linear relation between the MS value and the product weight, and explains why the MS signal can be used to control the injection molding process.
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Prydalnyi, Borys. "MECHATRONIC DEVICE FOR TWO-STAGE CLAMPING OF CYLINDRICAL OBJECTS IN MACHINE TOOL SPINDLES." Journal of Mechanical Engineering and Transport 13, no. 1 (2021): 118–23. http://dx.doi.org/10.31649/2413-4503-2021-13-1-118-123.
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The design of an electromechanical device for fixing cylindrical objects in the spindle units of technological equipment is presented. The new two-stage concept of the clamping process with a separated first stage is developed. The design of the presented mechanism provides advanced capabilities for control and regulation of its operating characteristics. The control system with the possibility of carrying out the first stage of clamping in automatic mode and without connecting to the upper-level control system in a technological machine is proposed. The involvement of electrical devices for the conversion and transmission of energy instead of their mechanical analogues is used as one of the promising ways to increase the performance efficiency of machine units. It helps to simplify and expand control capabilities, as well as reduce energy losses during intermediate transformations. The absence of mechanical energy converters in the proposed structure helps to reduce energy losses on intermediate transformations. The simplicity of the design expands the possibilities of integration of the proposed clamping mechanism into the structure of both new and existing technological machines in order to modernize it. This allows to achieve technical results, such as an expansion of the metalworking machines functionality, increase the level of automation of the clamping process and the accuracy of clamping objects in spindle units. The task is achieved by equipping the jaw of the clamping chuck with a special mechanism for identifying the presence of the object for clamping. For this goal, the clamping jaw is equipped with a probe that is capable of simultaneous force interaction with the object and the plunger. The plunger is rigidly attached to the magnetic element whose magnetic field has the possibility to interact with the magnetic field sensor. The sensor transmits its electrical signals to the control system of the device. The research results are aimed at meeting the requirements for effective control of clamping mechanisms with the possibility of automatic operation according to a preset algorithm for maintenance of optimal characteristics of a clamping process and a wide range of optional settings.
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Prydalnyi, B. I., and H. T. Sulym. "Mathematical Model of the Tensioning in the Collet Clamping Mechanism with the Rotary Movable Input Link on Spindle Units." Journal of Engineering Sciences 8, no. 1 (2021): E23—E28. http://dx.doi.org/10.21272/jes.2021.8(1).e4.
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Increasing machining productivity causes the cutting forces acting on tools or workpieces to grow and requires extra clamping forces for their fixation reliably. In the research, a mathematical model of the operation of the clamping mechanism for fixating cylindrical objects on the spindle of machine tools at the stage of tension is presented. The presented design of the mechanism contains screw gear and provides self-braking. Based on the calculation model, mathematical dependencies are developed to describe the relationship among the movements of the parts of the mechanism when clamping forces are growing. The presented analytical dependencies allow considering the stage of growing clamping forces separately when the conservative type of forces are prevailing in the mechanism’s operation. That stage of work when both types of forces of dissipative and potential characters exist is considered. The developed dependencies describe the position of parts of the clamping mechanism depending on the generalized coordinate. The angle of rotation of the input rotating link is used as the generalized coordinate. This fact allows calculating the position of the elements of the clamping mechanism of this type depending on time. Results of the research enhance understanding the pattern of the change in the interaction of the elements and forces that act in the mechanism during the final stage of clamping. The obtained mathematical dependencies are a precondition for the development of design methodology for mechanisms of this type.
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Othman, Mohd Hilmi, Sulaiman Hasan, and Muhammad Farid Shaari. "Development and Structural Analysis of Injection Moulding-Hydraulics Clamping Unit Testing System." Applied Mechanics and Materials 315 (April 2013): 156–60. http://dx.doi.org/10.4028/www.scientific.net/amm.315.156.
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This project is focusing on the development of a test unit for the hydraulically driven clamping system, typically used in injection moulding. The objectives of this project are to fabricate the model of clamping unit and to perform structural analysis based on the model design through simulation and by performing actual experiment on the real fabricated model. This actual test was conducted by compressing the load cell in between the two moulds halves in order to get the clamping force value through the data logger. The results obtained from simulation shows that the maximum stress of clamping unit with tie bar can achieve up to 11.2 MPa, with the safety value of 2.5. In the other hand, for the actual test experiment, the result the maximum clamping force produce is 3160N at 52bar of pressure. These values are important to be used as guidance in selecting the suitable injector part. As a conclusion, this clamping system has work properly and efficiently to be used for further research and a tool to understand more about the mechanism and the effects of clamping units in injection moulding process.
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Munro, Anna, Daniel J. Corsi, Lisa Martin, Michael Halpenny, Nicholas Dibdin, Heidi Elmoazen Elmoazzen, Mark Walker, and David S. Allan. "Obstetrical and neonatal factors associated with optimal public banking of umbilical cord blood in the context of delayed cord clamping." Clinical and Investigative Medicine 42, no. 3 (September 29, 2019): E56—E63. http://dx.doi.org/10.25011/cim.v42i3.33093.
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Purpose: To assess the association of specific newborn and maternal factors with indicators of increased blood-forming capacity in umbilical cord blood to
inform strategic collection strategies that could augment the quality of units in public cord blood banks.
Methods: Data regarding 268 consecutive cord blood units (CBUs) banked by Canadian Blood Services were analyzed. Multivariate analysis was performed to
identify factors associated with markers of hematopoietic potency and likelihood of utilization.
Results: Delayed clamping of the cord beyond 60 s was associated with reduced volume collected. Any delay in clamping of the cord was associated
with reduced total nucleated cell counts. Newborn weight >4,000 g was also associated with greater blood volume in the collection but not with other measures of hematopoietic potency. Cord blood acidosis at birth (pH
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Schiergens, Tobias S., Moritz Drefs, Maximilian Dörsch, Florian Kühn, Markus Albertsmeier, Hanno Niess, Markus B. Schoenberg, et al. "Prognostic Impact of Pedicle Clamping during Liver Resection for Colorectal Metastases." Cancers 13, no. 1 (December 29, 2020): 72. http://dx.doi.org/10.3390/cancers13010072.
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Pedicle clamping (PC) during liver resection for colorectal metastases (CRLM) is used to reduce blood loss and allogeneic blood transfusion (ABT). The effect on long-term oncologic outcomes is still under debate. A retrospective analysis of the impact of PC on ABT-demand regarding overall (OS) and recurrence-free survival (RFS) in 336 patients undergoing curative resection for CRLM was carried out. Survival analysis was performed by both univariate and multivariate methods and propensity-score (PS) matching. PC was employed in 75 patients (22%). No increased postoperative morbidity was monitored. While the overall ABT-rate was comparable (35% vs. 37%, p = 0.786), a reduced demand for more than two ABT-units was observed (p = 0.046). PC-patients had better median OS (78 vs. 47 months, p = 0.005) and RFS (36 vs. 23 months, p = 0.006). Multivariate analysis revealed PC as an independent prognostic factor for OS (HR = 0.60; p = 0.009) and RFS (HR = 0.67; p = 0.017). For PC-patients, 1:2 PS-matching (N = 174) showed no differences in the overall ABT-rate compared to no-PC-patients (35% vs. 40%, p = 0.619), but a trend towards reduced transfusion requirement (>2 ABT-units: 9% vs. 21%, p = 0.052; >4 ABT-units: 2% vs. 11%, p = 0.037) and better survival (OS: 78 vs. 44 months, p = 0.088; RFS: 36 vs. 24 months; p = 0.029). Favorable long-term outcomes and lower rates of increased transfusion demand were observed in patients with PC undergoing resection for CRLM. Further prospective evaluation of potential oncologic benefits of PC in these patients may be meaningful.
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Huang, Hu, Lu Fu, Hong Wei Zhao, and Cheng Li Shi. "Finite Element Simulations of an Inchworm Type Piezo-Driven Rotary Actuator." Advanced Materials Research 945-949 (June 2014): 1396–99. http://dx.doi.org/10.4028/www.scientific.net/amr.945-949.1396.
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The inchworm-driven actuator is an important type of piezo-driven actuators, which has high loading capacity, large motion range and high motion accuracy but involves complex structures, control and motion processes. In this paper, an inchworm type piezo-driven rotary actuator was introduced. Static and modal analyses of key units of the rotary actuator such as the clamping unit and the driving unit were carried out by finite element simulations to ensure that key units of the rotary actuator have enough strength and good dynamic characteristics. These simulation results will be helpful to improve structure design of the inchworm actuator.
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Bostan, Cem, Ayşem Kaya, and Zerrin Yiğit. "Changes in pentraxin 3 and oxidative parameters during coronary bypass grafting and factors affecting postoperative atrial fibrillation." Journal of International Medical Research 48, no. 11 (November 2020): 030006052096756. http://dx.doi.org/10.1177/0300060520967561.
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Objective The performance of coronary bypass grafting (CBG) induces a type of subclinical systemic inflammatory response syndrome. The present study was performed to examine the changes in pentraxin 3 (PTX3) and oxidative parameters during cross-clamping in patients undergoing CBG. We also examined factors affecting the development of postoperative atrial fibrillation (POAF). Method This study involved 40 patients who underwent elective on-pump CBG (33 men, 7 women; mean age, 60.8 ± 8.0 years). Blood specimens were drawn before anaesthesia and after aortic cross-clamping. POAF was detected by analysing the rhythm records of telemetry units for 96 hours postoperatively. Results The mean PTX3 concentration prior to surgery was 176.3 ± 148.4 pg/mL. After cross-clamping, it increased to 947.7 ± 377.2 pg/mL. The increase was statistically significant. Twelve patients had POAF. The leucocyte count and change in the oxidative stress index were significantly higher in patients without than with POAF. Although the increase in PTX3 was higher in patients without POAF, the difference was not statistically significant. Conclusion The PTX3 concentration significantly increases during CBG. A significant change in the oxidative stress index and a more intense increase in the PTX3 concentration were seen in patients without POAF.
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Tran, Chinh L., Janella M. Parucha, Priya Jegatheesan, and Henry C. Lee. "Delayed Cord Clamping and Umbilical Cord Milking among Infants in California Neonatal Intensive Care Units." American Journal of Perinatology 37, no. 02 (March 21, 2019): 151–57. http://dx.doi.org/10.1055/s-0039-1683876.
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Objective To assess the current practice of delayed cord clamping (DCC) and to determine patient and hospital factors that predict DCC. Study Design The California Perinatal Quality Care Collaborative (CPQCC) collects data on preterm and acutely ill infants. In 2016, 52 CPQCC neonatal intensive care units (NICUs) collected data on DCC. Hospital and patient characteristics were analyzed using multivariable logistic regression. Results Of 5,332 deliveries, 1,555 (29%) newborns received DCC. Hospital rates ranged from 0 to 74.5% and increased from 21 to 37% throughout 2016. Infants delivered at <32 weeks or with birth weight <1,500 g were more likely to receive DCC (odds ratio: 2.80; 95% confidence interval: 2.33, 3.36). Cesarean delivery was associated with less likelihood of DCC (odds ratio: 0.68; 95% confidence interval: 0.59, 0.79). After risk adjustment, 17 (33%) hospitals had higher than expected DCC rate. Hospitals with less than 50 NICU beds are more likely to practice DCC, whereas Level 3 American Academy of Pediatrics NICUs, nonprofit owned hospitals, and teaching institutions were less likely to practice DCC (p < 0.001). Conclusion There are opportunities to implement quality improvement activities to increase DCC rates.
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Xie, Xiaohui, and H. Sebastian Seung. "Equivalence of Backpropagation and Contrastive Hebbian Learning in a Layered Network." Neural Computation 15, no. 2 (February 1, 2003): 441–54. http://dx.doi.org/10.1162/089976603762552988.
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Backpropagation and contrastive Hebbian learning are two methods of training networks with hidden neurons. Backpropagation computes an error signal for the output neurons and spreads it over the hidden neurons. Contrastive Hebbian learning involves clamping the output neurons at desired values and letting the effect spread through feedback connections over the entire network. To investigate the relationship between these two forms of learning, we consider a special case in which they are identical: a multilayer perceptron with linear output units, to which weak feedback connections have been added. In this case, the change in network state caused by clamping the output neurons turns out to be the same as the error signal spread by backpropagation, except for a scalar prefactor. This suggests that the functionality of backpropagation can be realized alternatively by a Hebbian-type learning algorithm, which is suitable for implementation in biological networks.
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Luo, Wanjun, Bei Li, Guoqiang Lin, Ri Chen, and Rimao Huang. "Does cardioplegia leave room for postconditioning in paediatric cardiac surgery?" Cardiology in the Young 18, no. 3 (June 2008): 282–87. http://dx.doi.org/10.1017/s1047951108002072.
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AbstractBackgroundPostconditioning by brief episodes of ischaemia performed just at the time of reperfusion have been shown to reduce the size of infarcts in animal models, and in the clinical setting of percutaneous cardiac intervention. The clinical applicability of postconditioning in cardiac surgery remains to be determined. We investigated the effect of postconditioning on myocardial protection in children undergoing cardiac surgery.MethodsWe randomly assigned 40 patients scheduled for surgical correction of congenitally malformed hearts under cold blood cardioplegic arrest to postconditioning or control treatment. Postconditioning was performed by two cycles of 30 seconds ischaemia and 30 seconds reperfusion using aortic reclamping, and declamping started 30 seconds after cardioplegic arrest. We assayed creatine kinase-MB, troponin I, transcardiac release of lactate and neutrophil counts.ResultsThe types of procedure, age, bypass and aortic cross-clamping times were similar in both groups. The postoperative peaks of creatine kinase-MB and troponin I were lower after aortic de-clamping in the postconditioned patients compared with their controls (128 ± 48 units per liter as opposed to 199 ± 79 units per liter, p = 0.016, and 0.34 ± 0.21 nanograms per milliliter as opposed to 0.61 ± 0.53 nanograms per milliliter, p = 0.05), with reduced inotropic scores in those submitted to postconditioning compared with their controls (4.8 ± 3.1 versus 2.3 ± 1.5, p = 0.036). Transcardiac release of lactate was reduced in the postconditioned patients compared with their controls (0.10 ± 0.27 as opposed to 0.37 ± 0.43 millimols per liter, p = 0.048). No differences between groups were found for transcardiac neutrophil count during reperfusion (10.8 ± 6.3% for postconditioning versus 14.0 ± 8.7% for controls, p = 0.48).ConclusionsOur study demonstrates that postconditioning may protect the myocardium of children undergoing cold blood cardioplegic arrest. These data support the need for a larger clinical trial of postconditiong in children undergoing cardiac surgery.
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Mao, Jun, Wei Kang Li, and Jian Gang Li. "Study on Manufacture Technology for Enhancing the Life of Mining Flat Type Chain Connector Units." Advanced Materials Research 156-157 (October 2010): 153–56. http://dx.doi.org/10.4028/www.scientific.net/amr.156-157.153.
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To enhance the structure strength and working life of the existing ladder-type chain connector, and chain connector productivity and manufacture craftwork. The ANSYS finite element software is utilized to simulate contact non-linear finite element analysis of ladder type chain connector. And the static and dynamic experiments are carried on several samples. Finite element simulation results show that the main part of stress concentration is in teeth roots; experiments results show that the teeth roots are the fragile parts in the chain connector, the results of finite element analysis is conformed to the results of the experiments, thus that the ANSYS finite element software is utilized to simulate contact non-linear finite element analysis of chain connector is reasonable. Because of the shortcoming of straight tooth chain connector, then promoted a chain connector of cambered surface tooth structure. Through the analysis, it shows that cambered surface can augment the contact areas in teeth, and prevent partial loading in teeth meshing. When chain connector manufactured, clamping tongs are quite complex, but the petal-type clamps structures are adopted, that can carry out volume-producing, thereby, and the productivity and processing precision are improved.
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Koprivica, Radenko, Radisa Cvijovic, Ranka Koprivica, and Radmila Smiljanic. "Injuries of the retrohepatic inferior vena cava and the liver." Vojnosanitetski pregled 65, no. 6 (2008): 481–84. http://dx.doi.org/10.2298/vsp0806481k.
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Beckground. Injuries of the retrohepatic inferior vena cava, and the liver have mortality rate up to 71-78%. We presented a patient with combined injury of the retrohepatic inferior vena cava, liver, craniocerebral and thoracic traumas, inflicted in a traffic accident. Case report. Man, 20 years old has been injured in a traffic accident. At admission, 20 minutes after the injury, the patient was comatose and hypotensive. Bloody content was obtained by abdominal tracer. The patient underwent emergent laparotomy, utilizing trifurcated incision and cell saver device. Abdominal exploration revealed two liters of free blood and massive retroperitoneal hematoma. Manual compression of the liver was done, as well as perihepatic packing, complete hepatic vascular exclusion and mobilization of the right liver lobe. Due to impressive chemodynamic instability supraceliac aortic clamping was performed. Upon exposure of the retrohepatic inferior vena cava and right liver lobe, multiple lacerations of retrohepatic inferior vena cava and right hepatic vein, and right hepatic vein avulsion were found. We also identified an injury of VII and VIII segments of the liver (grade V according to the Moore's classification). Nonexpansive hepatoduodenal ligament hematoma and the injury of II and III segments of the liver group II/III according to Moore were found. Venorrhaphy of the inferior vena cava was done in the area of circumference of the right hepatic vein, a portion of which served as autologous vein patch. Continuous prolene 3/0 venorrhaphy of the distal caval laceration was done. Total caval and aorta clamping time of the inferior vena cava was 41 minutes. Atypical resection, debridment, of hepatic segments was done by using a harmonic scalpel. Hepatoduodenal ligament was declamped after 65 minutes. Fibrin glue was applied on the resectioned area of liver. The patient received 3.2 l of autologuos blood transfusion with 5 units of packed red blood cells, 6 units of fresh frozen plasma, 13 units of concentrated thrombocytes and 15 units of cryoprecipitates. Due to coagulopathy, factor rVIIa was administered. Bilateral toracal drainage was done. Small bilateral contusions of the frontal part of the brain were noticed but the patient successfully recovered and was dismissed after three weeks. Conclusion. Combined injuries of the inferior vena cava and the liver befall into the most complex vascular traumas, thus representing a challenge for any complete medical team to manage them. The patient presented in our study was urgently transported to the hospital, immediately operated on applying modern doctrines of anesthesiology, transfusiology and vascular surgery that, all together, resulted into favorable treatment outcome with no distant complications.
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Manjunatha, B. M., S. Nagaraja Rao, A. Suresh Kumar, K. Shaguftha Zabeen, S. Lakshminarayanan, and A. V. Reddy. "An Optimized Multilevel Inverter Topology with Symmetrical and Asymmetrical DC Sources for Sustainable Energy Applications." Engineering, Technology & Applied Science Research 10, no. 3 (June 7, 2020): 5719–23. http://dx.doi.org/10.48084/etasr.3509.
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This paper proposes an optimized Multi-Level Inverter (MLI) topology with symmetrical and asymmetrical DC sources for sustainable energy applications. The proposed MLI has optimized components to reduce size, cost, and installation area in comparison with traditional MLIs. It also improves output power quality by reducing harmonics in the stepped output, and hence it can be used for sustainable energy applications with a grid interface. The proposed inverter is equipped with six switching devices, one clamping diode, and two DC sources. It produces a five-level stepped output when using symmetrical DC sources and a seven-level stepped output when using asymmetrical DC sources. In this topology, the six switching devices are divided into two units, namely the level generator and the polarity generator units, the switches used in the level generator are responsible for producing the required number of levels in the form of rectified stepped output and the switches used in the polarity generator are responsible for converting the rectified stepped waveform to stepped AC output. The simulation results verify the operation of the MLI when fed with linear load with symmetrical and asymmetrical DC sources, and the experimental output results are presented for validation.
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Cerpinska, Marina, Renars Vitols, and Oskars Simanis. "Electromagnetic Vibrations of Hydropower Generator Stator Core and Transformer Core at 100 Hz Frequency." Solid State Phenomena 260 (July 2017): 278–88. http://dx.doi.org/10.4028/www.scientific.net/ssp.260.278.
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This paper aimed to compare obtained results and collected theory for 100 Hz frequency vibration of hydropower generator stator core and transformer core. Electromagnetic vibration with 100 Hz frequency occurred both at slow-speed salient poles synchronous generator stator core and oil-filled power transformers tank, but the nature of hydropower and transformer 100 Hz vibration was different. The vibration analysis procedure and acceptable limits for hydropower generator stator core were already covered in the standards, while the health grade system for vibration measurements of power transformer has not beet yet developed. This study discussed the experimental results aiming to extend the knowledge about reasoning for non-existing statistical health grade system, based on power transformers vibrations, measured on tank. The experimental results of hydropower generator stator and power transformer spectrum were reported. Two salient pole hydropower generator stators and four transformers with different construction (including shell-type) and different cooling system (including air forced cooling system) were chosen to present vibration spectrum results. It was demonstrated that increasing clamping pressure of the core does not always reduce 100 Hz harmonic component neither for hydrogenerator stator, nor for transformer. Bad clamping pressure and defects in core, in contrary, will not result into increase of 100 Hz component for some units. Results showed that air forced cooling equipment (fans) would not add higher harmonics to vibration spectrum of the power transformer tank. It was shown that the shell-type construction of transformer core would not necessarily result in high vibration values on tank.
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Duley, Lelia, Jon Dorling, Susan Ayers, Sandy Oliver, Charles William Yoxall, Andrew Weeks, Chris Megone, et al. "Improving quality of care and outcome at very preterm birth: the Preterm Birth research programme, including the Cord pilot RCT." Programme Grants for Applied Research 7, no. 8 (September 2019): 1–280. http://dx.doi.org/10.3310/pgfar07080.
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Background Being born very premature (i.e. before 32 weeks’ gestation) has an impact on survival and quality of life. Improving care at birth may improve outcomes and parents’ experiences. Objectives To improve the quality of care and outcomes following very preterm birth. Design We used mixed methods, including a James Lind Alliance prioritisation, a systematic review, a framework synthesis, a comparative review, qualitative studies, development of a questionnaire tool and a medical device (a neonatal resuscitation trolley), a survey of practice, a randomised trial and a protocol for a prospective meta-analysis using individual participant data. Setting For the prioritisation, this included people affected by preterm birth and health-care practitioners in the UK relevant to preterm birth. The qualitative work on preterm birth and the development of the questionnaire involved parents of infants born at three maternity hospitals in southern England. The medical device was developed at Liverpool Women’s Hospital. The survey of practice involved UK neonatal units. The randomised trial was conducted at eight UK tertiary maternity hospitals. Participants For prioritisation, 26 organisations and 386 individuals; for the interviews and questionnaire tool, 32 mothers and seven fathers who had a baby born before 32 weeks’ gestation for interviews evaluating the trolley, 30 people who had experienced it being used at the birth of their baby (19 mothers, 10 partners and 1 grandmother) and 20 clinicians who were present when it was being used; for the trial, 261 women expected to have a live birth before 32 weeks’ gestation, and their 276 babies. Interventions Providing neonatal care at very preterm birth beside the mother, and with the umbilical cord intact; timing of cord clamping at very preterm birth. Main outcome measures Research priorities for preterm birth; feasibility and acceptability of the trolley; feasibility of a randomised trial, death and intraventricular haemorrhage. Review methods Systematic review of Cochrane reviews (umbrella review); framework synthesis of ethics aspects of consent, with conceptual framework to inform selection criteria for empirical and analytical studies. The comparative review included studies using a questionnaire to assess satisfaction with care during childbirth, and provided psychometric information. Results Our prioritisation identified 104 research topics for preterm birth, with the top 30 ranked. An ethnographic analysis of decision-making during this process suggested ways that it might be improved. Qualitative interviews with parents about their experiences of very preterm birth identified two differences with term births: the importance of the staff appearing calm and of staff taking control. Following a comparative review, this led to the development of a questionnaire to assess parents’ views of care during very preterm birth. A systematic overview summarised evidence for delivery room neonatal care and revealed significant evidence gaps. The framework synthesis explored ethics issues in consent for trials involving sick or preterm infants, concluding that no existing process is ideal and identifying three important gaps. This led to the development of a two-stage consent pathway (oral assent followed by written consent), subsequently evaluated in our randomised trial. Our survey of practice for care at the time of birth showed variation in approaches to cord clamping, and that no hospitals were providing neonatal care with the cord intact. We showed that neonatal care could be provided beside the mother using either the mobile neonatal resuscitation trolley we developed or existing equipment. Qualitative interviews suggested that neonatal care beside the mother is valued by parents and acceptable to clinicians. Our pilot randomised trial compared cord clamping after 2 minutes and initial neonatal care, if needed, with the cord intact, with clamping within 20 seconds and initial neonatal care after clamping. This study demonstrated feasibility of a large UK randomised trial. Of 135 infants allocated to cord clamping ≥ 2 minutes, 7 (5.2%) died and, of 135 allocated to cord clamping ≤ 20 seconds, 15 (11.1%) died (risk difference –5.9%, 95% confidence interval –12.4% to 0.6%). Of live births, 43 out of 134 (32%) allocated to cord clamping ≥ 2 minutes had intraventricular haemorrhage compared with 47 out of 132 (36%) allocated to cord clamping ≤ 20 seconds (risk difference –3.5%, 95% CI –14.9% to 7.8%). Limitations Small sample for the qualitative interviews about preterm birth, single-centre evaluation of neonatal care beside the mother, and a pilot trial. Conclusions Our programme of research has improved understanding of parent experiences of very preterm birth, and informed clinical guidelines and the research agenda. Our two-stage consent pathway is recommended for intrapartum clinical research trials. Our pilot trial will contribute to the individual participant data meta-analysis, results of which will guide design of future trials. Future work Research in preterm birth should take account of the top priorities. Further evaluation of neonatal care beside the mother is merited, and future trial of alternative policies for management of cord clamping should take account of the meta-analysis. Study registration This study is registered as PROSPERO CRD42012003038 and CRD42013004405. In addition, Current Controlled Trials ISRCTN21456601. Funding This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 7, No. 8. See the NIHR Journals Library website for further project information.
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Chiari, Pascal, Denis Angoulvant, Nathan Mewton, Olivier Desebbe, Jean-François Obadia, Jacques Robin, Fadi Farhat, et al. "Cyclosporine Protects the Heart during Aortic Valve Surgery." Anesthesiology 121, no. 2 (August 1, 2014): 232–38. http://dx.doi.org/10.1097/aln.0000000000000331.
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Abstract Background: Part of the myocardial damage occurring during cardiac surgery is a consequence of reperfusion injury. Cyclosporine, a potent inhibitor of the opening of the mitochondrial permeability transition pore, attenuates reperfusion injury in patients with acute ST-segment elevation myocardial infarction. This study investigated whether the administration of cyclosporine just before the aortic cross-unclamping would reduce myocardial injury in patients undergoing aortic valve surgery. Methods: This study was a monocentric, prospective, randomized, single-blinded, controlled trial. Sixty-one patients, scheduled for elective aortic valve surgery, were randomly assigned (computer-generated randomization sequence) to receive either an intravenous bolus of cyclosporine (2.5 mg/kg, cyclosporine group, n = 30) or normal saline (control group, n = 31) 10 min before aortic cross-unclamping. The primary endpoint was the 72-h area under the curve for cardiac troponin I. Results: Both groups were similar with respect to baseline characteristics and aortic cross-clamping duration. A significant 35% reduction of area under the curve for cardiac troponin I was observed in the cyclosporine group compared with the control group (242 ± 225 vs. 155 ± 71 arbitrary units, mean ± SD; mean difference, −86.2 ± 42.5; 95% CI, −172.3 to −0.1; P = 0.03). Cyclosporine beneficial effect remained significant after adjustment for aortic cross-clamping duration in each group (mean difference, −88 ± 34, 95% CI, −157 to −19; P = 0.01). None of the treated patients had significant side effects (odds ratio, 0.64; 95% CI, 0.16 to 2.55; P = 0.52). Conclusions: Cyclosporine administration at the time of reperfusion protects against reperfusion injury in patients undergoing aortic valve surgery. The clinical benefit of this protection requires confirmation in a larger clinical trial.
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Law, Mohit, Hendrik Rentzsch, and Steffen Ihlenfeldt. "Evaluating Mobile Machine Tool Dynamics by Substructure Synthesis." Advanced Materials Research 1018 (September 2014): 373–80. http://dx.doi.org/10.4028/www.scientific.net/amr.1018.373.
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Mobile machining solutions use autonomous machining units that can be transported to different part locations, making possible easy maintenance and repair of large industrial equipment. Every new part and location results in different boundary conditions for the mobile machine tool-part system; influencing the dynamics of the combined system and necessitating different strategies for part/machine referencing and clamping. To facilitate efficient mutability and modularity in mobile machining solutions, this paper presents a dynamic substructuring strategy that combines the response characteristics of the mobile machine unit with that of two different simulated base models under varying levels of contact stiffness and damping to obtain the synthesized mobile machine tool dynamic response. Numerical verification of the approach is provided. Framework presented can also combine measured response of parts for which models may not be available a priori. Methods presented provide experimental guidelines for establishing strategies for part/machine referencing, and planning of machining strategies based on the evaluated dynamics.
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Kotfis, Katarzyna, Dominika Jamioł-Milc, Karolina Skonieczna-Żydecka, Marcin Folwarski, and Ewa Stachowska. "The Effect of Preoperative Carbohydrate Loading on Clinical and Biochemical Outcomes after Cardiac Surgery: A Systematic Review and Meta-Analysis of Randomized Trials." Nutrients 12, no. 10 (October 12, 2020): 3105. http://dx.doi.org/10.3390/nu12103105.
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Background and aim: Preoperative fasting leads to metabolic stress and causes insulin resistance in patients undergoing cardiac surgery. The aim of this study was to assess the effect of preoperative oral carbohydrate loading (OCH) on outcome in patients undergoing planned cardiac surgery by systematically reviewing the literature and synthesizing evidence from randomized controlled trials (RCTs). Methods: Systematic search of PubMed/MEDLINE/Embase/Cinahl/Web of Science/ClinicalTrials databases was performed to identify relevant RCTs from databased inception until 05/03/2020. We included studies that compared outcome measures between OCH with control (placebo or standard starvation). We conducted a random-effect meta-analysis of clinical and biochemical parameters. Results: Nine studies (N = 9) were included with a total of 507 patients. OCH significantly decreased aortic clamping duration (n = 151, standardized mean difference (SMD) = −0.28, 95% confidence interval (CI) = −0.521 to −0.038, p = 0.023 and differences in means (DM) = −6.388, 95%CI = −11.246 to −1.529, p = 0.010). Patients from treatment groups had shorter intensive care unit (ICU) stay (n = 202, SMD = −0.542, 95%CI = −0.789 to −0.295, p < 0.001 and DM = −25.925, 95%CI = −44.568 to −7.283, p = 0.006) and required fewer units of insulin postoperatively (n = 85, SMD = −0.349, 95%CI = −0.653 to −0.044, p = 0.025 and DM = −4.523, 95%CI = −8.417 to −0.630, p = 0.023). The necessity to use inotropic drugs was significantly lower in the OCH group (risk ratio (RR) = 0.795, 95%CI = 0.689 to 0.919, p = 0.002). All other primary outcomes did not reveal a significant effect. Conclusions: Preoperative OCH in patients undergoing cardiac surgery demonstrated a 20% reduction in the use of inotropic drugs, a 50% reduction of the length of ICU stay, a 28% decrease in aortic clamping duration and a 35% decrease of postoperative insulin requirement.
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Mo, Ansheng, Zhaoke Wen, Hui Lin, Changchao Lu, and Shengjin Liang. "Mitral Valve Replacements Under On-Pump Beating Heart and Lung Perfusion/Ventilation Using a Minithoracotomy: An Experience with 11 Cases." Heart Surgery Forum 15, no. 3 (June 14, 2012): 133. http://dx.doi.org/10.1532/hsf98.20121013.
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<p><b>Background:</b> The primary aims of minimally-invasive cardiac valve surgery are to lessen the impact of the incision, extracorporeal circulation, myocardial ischemia, and pulmonary ischemia, to obtain satisfactory therapeutic results, and to allow a quicker rehabilitation. In this study, the feasibility of minimally-invasive mitral valve replacements without ascending aorta and vena cava cross-clamping under beating heart was evaluated by surveying 11 patients.</p><p><b>Methods:</b> Preoperative risk factors, intraoperative techniques, and postoperative complications were surveyed and evaluated for one year (April 1, 2009 to March 30, 2010) in 11 patients who had undergone beating-heart mitral valve replacement surgery at The People's Hospital of Guangxi Zhuang Autonomous Region. Minithoracotomy and femoral arterial cannulation procedures were used in the surgeries for cardiopulmonary bypass (CPB) without ascending aorta and vena cava cross-clamping.</p><p><b>Results:</b> The operations were performed successfully in all 11 patients. The CPB time was 52.80 � 11.36 minutes; the mean postoperative mechanical ventilation assistance time was 8.20 � 2.84 hours; and the mean transfusion volume of red cells was 2.20 � 1.04 units. There were no cerebral complications, no periprosthetic leakage, no occurrence of permanent high-degree atrioventricular blockage, and no mortality.</p><p><b>Conclusion:</b> Mitral valve replacement on the beating heart using a minithoracotomy and femoral arterial cannulation for CPB without ascending aorta and vena cava crossclamping under pulmonary ventilation is feasible. A larger number of patients are required to further characterize the efficacy and safety of this procedure.</p>
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Luo, Wanjun, Ming Zhu, Rimao Huang, and Yangde Zhang. "A comparison of cardiac post-conditioning and remote pre-conditioning in paediatric cardiac surgery." Cardiology in the Young 21, no. 3 (January 25, 2011): 266–70. http://dx.doi.org/10.1017/s1047951110001915.
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AbstractBackgroundRemote ischaemic pre-conditioning and cardiac ischaemic post-conditioning provide myocardial protection in cardiac surgery. However, these two endogenous strategies have not been directly compared in a clinical setting. The purpose of this study was to compare the efficacy of remote ischaemic pre-conditioning and post-conditioning in providing myocardial protection to children undergoing cardiopulmonary bypass for surgical repair of ventricular septal defect.MethodsWe randomly assigned 60 paediatric patients scheduled for surgical correction of congenital ventricular septal defect to the post-conditioning group (n = 20), remote pre-conditioning group (n = 20), or control group (n = 20). Post-conditioning consisted of 30 seconds of ischaemia and 30 seconds of reperfusion achieved by clamping and unclamping the aorta, repeated three times over 3 minutes immediately after cardioplegic arrest. Remote ischaemic pre-conditioning consisted of 5 minutes of lower limb ischaemia followed by 5 minutes of reperfusion using a blood-pressure cuff inflated to a pressure of 200 millimetres of mercury, also repeated three times over 30 minutes. We assayed creatine kinase-MB, troponin I.ResultsMean age, cardiopulmonary bypass times, and aortic cross-clamp times were matched across groups. Both post-conditioning and remote ischaemic pre-conditioning reduced the peak release of creatine kinase-MB (86.1 plus or minus 24.1 units per litre and 92.8 plus or minus 20.6 units per litre, respectively, versus 111.0 plus or minus 44.6 units per litre in the control, p less than 0.05) and troponin I (0.28 plus or minus 0.10 nanogram per millilitre and 0.26 plus or minus 0.09 nanogram per millilitre, respectively, versus 0.49 plus or minus 0.19 nanogram per millilitre in the control group, p less than 0.05).ConclusionsOur study demonstrates that ischaemic post-conditioning and remote ischaemic pre-conditioning provide comparable myocardial benefit in children undergoing cold blood cardioplegic arrest.
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Seyedkashi, S. M. H., Golam Hosein Liaghat, Hassan Moslemi Naeini, S. M. Mahdavian, and M. Hoseinpour Gollo. "Numerical and Experimental Study of Two-Layered Tube Forming by Hydroforming Process." Advanced Materials Research 264-265 (June 2011): 102–7. http://dx.doi.org/10.4028/www.scientific.net/amr.264-265.102.
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Hydroforming is an advanced process in automotive and aerospace industries to form metal tubes into desired shapes by high pressure fluid. The formation of a two layered tubes has been investigated both numerically and experimentally by a pressurized fluid fed into the internal tube through a nonlinear path with no axial feeding. The experimental setup including two units of die clamping system and pressure intensification system has been designed and built in Tarbiat Modares University. The internal and external layers of hydroformed tubes are used aluminum and copper alloys respectively. Effects of different friction conditions on tubes formability have been investigated. Finite element simulation is performed with LS-Dyna FE explicit code using ETA/Dynaform as the preprocessor. The simulation results show that the part can be formed successfully with the internal pressure of 61 MPa. The finite element results are in agreement with experimental results. It is also shown that imposing high friction condition for external tube and low friction condition for internal tube both will fail more likely.
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Lin, Samuel I. En. "Stress Birefringence in Photonic Crystal Fibers Used in a Novel Field Installable LC Type Optical Connector." Key Engineering Materials 364-366 (December 2007): 404–7. http://dx.doi.org/10.4028/www.scientific.net/kem.364-366.404.
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Photonic crystal fibers (PCFs) have recently attracted a great deal of interest because of their unique characteristics and many controllable features. They include a wide range of single mode operation, highly birefringent characteristics (~10-3), high-power light transmission, etc. The field-installable LC connectors tend to be of the larger connector types in the fiber-to-the-home (FTTH) distribution units. In these designs, fibers are clamped inside a splice assembly and are stressed within the connector. In this research, we first developed a novel cam-type mechanism for field-use LC connector. The fiber stress was analyzed via a commercial available finite element program. The stress birefringence distributions of single mode fiber and air-silica based PCFs were calculated by stress photoelastic effect. We further studied the effect of air-hole size on the stressinduced birefringence of PCFs. The results indicate that stress-induced birefringence decreases as air-hole size increase. On the other hand, the birefringence increases as applied clamping force increases on the single mode fiber.
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Ikuma, Mutsuhiro, John Geibel, Henry J. Binder, and Vazhaikkurichi M. Rajendran. "Characterization of Cl-HCO3 exchange in basolateral membrane of rat distal colon." American Journal of Physiology-Cell Physiology 285, no. 4 (October 2003): C912—C921. http://dx.doi.org/10.1152/ajpcell.00396.2002.
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Sodium-independent Cl movement (i.e., Cl-anion exchange) has not previously been identified in the basolateral membranes of rat colonic epithelial cells. The present study demonstrates Cl-HCO3 exchange as the mechanism for 36Cl uptake in basolateral membrane vesicles (BLMV) prepared in the presence of a protease inhibitor cocktail from rat distal colon. Studies of 36Cl uptake performed with BLMV prepared with different types of protease inhibitors indicate that preventing the cleavage of the COOH-terminal end of AE2 protein by serine-type proteases was responsible for the demonstration of Cl-HCO3 exchange. In the absence of voltage clamping, both outward OH gradient (pHout/pHin: 7.5/5.5) and outward HCO3 gradient stimulated transient 36Cl uptake accumulation. However, voltage clamping with K-ionophore, valinomycin, almost completely (87%) inhibited the OH gradient-driven 36Cl uptake, whereas HCO3 gradient-driven 36Cl uptake was only partially inhibited (38%). Both electroneutral HCO3 and OH gradient-driven 36Cl uptake were 1) completely inhibited by DIDS, an anion exchange inhibitor, with a half-maximal inhibitory constant ( Ki) of ∼26.9 and 30.6 μM, respectively, 2) not inhibited by 5-nitro-2-(3-phenylpropylamino)benzoic acid(NPPB), a Cl channel blocker, 3) saturated by increasing extravesicular Cl concentration with a Km for Cl of ∼12.6 and 14.2 mM, respectively, and 4) present in both surface and crypt cells. Intracellular pH (pHi) was also determined with 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein-acetomethylester (BCECF-AM) in an isolated superfused crypt preparation. Removal of Cl resulted in a DIDS-inhibitable increase in pHi both in HCO3-buffered and in the nominally HCO3-free buffered solutions (0.28 ± 0.02 and 0.11 ± 0.02 pH units, respectively). We conclude that a carrier-mediated electroneutral Cl-HCO3 exchange is present in basolateral membranes and that, in the absence of HCO3, Cl-HCO3 exchange can function as a Cl-OH exchange and regulate pHi across basolateral membranes of rat distal colon.
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Wang, Chang Zhou, Xi Liang Liu, Jin Chun Song, and Zhi Wei Zhang. "Dynamic Research of the Split-Pillar Rotation Process for Electroslag Remelting Furnace." Applied Mechanics and Materials 52-54 (March 2011): 959–63. http://dx.doi.org/10.4028/www.scientific.net/amm.52-54.959.
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Electroslag Remelting (ESR) technology is a main method of special metallurgy; and split pillar is one of the most important mechanical units of ESR. The split pillar works not only as the mother body of ESR cross arm, but also as the rotation driving device of the cross arm. Since the tremendous mass of the cross arm and electrodes, serious inertia torque generates when the split pillar rotates, which leads to motion instability and problems of angle location and even safety threatens. In this paper, based on virtual machine technology, dynamic research of the rotation process of the electroslag-remelting-furnace split pillar was proceeded; influences of driving torque applied on the split pillar was researched, as the driving torque being constant, anti-step and with brake torque. 3D solid model of the split pillar and clamping device were established; main technical parameters were accomplished; and simulation research of the dynamic process was proceeded. It was found that, appropriate brake torque was important to better motion stability of the split pillar. The best brake torque was acquired, and the action time of the brake torque was obtained.
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Ratjen, F., R. Zinman, A. R. Stark, L. E. Leszczynski, and M. E. Wohl. "Effect of changes in lung volume on respiratory system compliance in newborn infants." Journal of Applied Physiology 67, no. 3 (September 1, 1989): 1192–97. http://dx.doi.org/10.1152/jappl.1989.67.3.1192.
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Total respiratory system compliance (Crs) at volumes above the tidal volume (VT) was studied by use of the expiratory volume clamping (EVC) technique in 10 healthy sleeping unsedated newborn infants. Flow was measured with a pneumotachograph attached to a face mask and integrated to yield volume. Volume changes were confirmed by respiratory inductance plethysmography. Crs measured by EVC was compared with Crs during tidal breathing determined by the passive flow-volume (PFV) technique. Volume increases of approximately 75% VT were achieved with three to eight inspiratory efforts during expiratory occlusions. Crs above VT was consistently greater than during tidal breathing (P less than 0.0005). This increase in Crs likely reflects recruitment of lung units that are closed or atelectatic in the VT range. Within the VT range, Crs measured by PFV was compared with that obtained by the multiple-occlusion method (MO). PFV yielded greater values of Crs than MO (P less than 0.01). This may be due to braking of expiratory airflow after the release of an occlusion or nonlinearity of Crs. Thus both volume recruitment and airflow retardation may affect the measurement of Crs in unsedated newborn infants.
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Wang, Bonnie R., Vincent L. Rowe, Sung Wan Ham, Sukgu Han, Kaushal Patel, Fred A. Weaver, and Karen Woo. "A Prospective Clinical Evaluation of the Effects of Intraoperative Systemic Anticoagulation in Patients Undergoing Arteriovenous Fistula Surgery." American Surgeon 76, no. 10 (October 2010): 1112–14. http://dx.doi.org/10.1177/000313481007601020.
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No standard presently exists for the use of systemic heparin during angioaccess surgery to decrease the incidence of postoperative thrombotic complications. Our objective was to study the effects of intraoperatively administered heparin on 30-day patency and postoperative bleeding complications in patients undergoing autogenous arteriovenous (AV) fistula surgery. A prospective, double-blinded, randomized controlled study was performed on 48 patients undergoing AV fistula creation from April 2007 through November 2009. Of the 48 patients, 22 were randomized to the control group and received no heparin. Twenty-six were randomized to receive heparin (75 units/kg intravenously) before clamping of the artery. There was no significant difference in 30-day patency between the heparin and control groups (92% vs 86%, P = 0.65), respectively. Three patients (12%) developed hematomas in the heparin group compared with one (5%) in the control group; however the difference was not statistically significant ( P = 0.61). The results suggest that intraoperative administration of heparin has no statistically significant effect on 30-day patency rates or postoperative bleeding complications. Larger trials with longer term follow-up and assessment of maturation rates are needed to determine the effect of intraoperative anticoagulation on these outcomes of arteriovenous fistula surgery.
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Ambrogio, G., L. Filice, L. De Napoli, and M. Muzzupappa. "A simple approach for reducing profile diverting in a single point incremental forming process." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 219, no. 11 (November 1, 2005): 823–30. http://dx.doi.org/10.1243/095440505x32797.
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Incremental forming applications are currently increasing in industry, especially for the production of small batches or single components. In fact, sufficient know-how is now available for the manufacture of simple products. However, further efforts are required to reduce the drawbacks of typical incremental forming processes, which compromise important advantages in terms of costs and flexibility. First of all the duration of the process, usually a few minutes, influences this kind of process, even if the operations are carried out on highspeed digitally controlled units. A tendency to produce inaccurate parts can reduce industrial interest with respect to incremental forming. Different approaches could be proposed to reduce this drawback, and a feasible and easily implemented strategy is the design of modified trajectories able to take into account both springback effects and stiffness reduction owing to specific clamping equipment. In this paper, such a strategy is pursued by integrating an on-line measuring system, composed of a digital inspector and a computer numerically controlled (CNC) open program. The geometry obtained is sampled in particular steps and an appropriate routine modifies the coordinates of the future punch path. This procedure of automatic control has been developed using an effective finite element (FE) code. An experimental design illustrates the potential use of the suggested methodology.
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Kunkevich, D. P., I. I. Polozkov, and A. A. Baryshev. "Automated synthesis of technological fixture constructions." «System analysis and applied information science», no. 4 (December 30, 2019): 39–45. http://dx.doi.org/10.21122/2309-4923-2019-4-39-45.
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At the initial stage of engineering design it has to determine the set of units of design object and topological relations between them. The solution making at this stage is very efficiently because the set of operations may be carried out: adding components into the project, mating them to each other’s etc. The procedures of such kind are monotonous and time consuming. Article is dedicated to automation of topological design. However, the creation and adoption of design decisions is a difficult creative task. Currently, there are several approaches that can be applied to specific types of objects, such as injection molds, blacksmith dies, etc. Most of them are various kinds of technological equipment. There is another type of such equipment – fixtures for locating and clamping parts on the technological operations of assembly, welding, cutting, etc. Automated synthesis of fixtures is considered in this article. A method for determining the design situation is proposed. The method is based on location theory and involves the analysis of a solid model of the object being located. An example of carrier system is presented too. It is assumed that the content of the article will be useful for development of application based on CAD system. Moreover, the engineer – CAD-user himself can do this without involving a professional programmer.
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Goodenough, Christopher J., Tyler A. Cobb, and John B. Holcomb. "Use of REBOA to stabilize in-hospital iatrogenic intra-abdominal hemorrhage." Trauma Surgery & Acute Care Open 3, no. 1 (October 2018): e000165. http://dx.doi.org/10.1136/tsaco-2018-000165.
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Resuscitative endovascular balloon occlusion of the aorta (REBOA) has become an increasingly popular alternative to emergency thoracotomy and aortic cross-clamping in patients with exsanguinating hemorrhage.1 This new capability is increasingly being used in non-trauma situations.2 3 This report demonstrates another novel use of REBOA for iatrogenic intra-abdominal hemorrhage.An 83-year-old man with multiple medical comorbidities and a history of chronic mesenteric ischemia was admitted to our institution for an elective mesenteric revascularization. Revascularization was unsuccessful, despite attempts to cross the lesion. Postprocedure, the patient developed a right groin hematoma, and CT on postprocedure day 0 demonstrated a femoral artery pseudoaneurysm and subintimal contrast at the level of the celiac artery, representing an iatrogenic dissection.The following day, he complained of dizziness. Physical examination revealed a blood pressure of 68/35 mm Hg, heart rate of 100 beats per minute, and a distended abdomen. Because the surgical intensive care unit (SICU) was full, he was transferred to the neurotrauma intesive care unit (NTICU) and intubated for hemodynamic instability. A chest X-ray revealed a prior thoracic endovascular aortic repair (figure 1), but no intrathoracic hemorrhage or pathology. Bedside ultrasonography revealed intra-abdominal fluid. Laboratory workup showed hemoglobin of 6.1 g/dL, from 10.9 the previous day. The patient was given two units of packed red blood cells, without response. The intensive care unit (ICU) team initiated norepinephrine, with minimal improvement despite increasing doses. Figure 1Chest X-ray with catheter in zone 1. Arrows mark the proximal and distal markers of the resuscitative endovascular balloon occlusion of the aorta.What would you do?Transfuse two units of packed red blood cells and observe.Proceed to the operating room (OR) for exploratory laparotomy.Endovascular balloon occlusion of the aorta (zone 1).
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Lopriore, Enrico. "Updates in Red Blood Cell and Platelet Transfusions in Preterm Neonates." American Journal of Perinatology 36, S 02 (June 25, 2019): S37—S40. http://dx.doi.org/10.1055/s-0039-1691775.
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AbstractAnemia and thrombocytopenia occur frequently in preterm neonates and the majority of them require at least one blood transfusion during the first few weeks of life. However, there is no international consensus on optimal transfusion management neither for red blood cell nor for platelet transfusions, resulting in large worldwide variations in transfusion practices between neonatal intensive care units. In the past decade, several studies performed in adults, infants as well as neonates showed that restrictive transfusion guidelines are just as safe as liberal guidelines. In fact, some studies even showed that liberal guidelines could be associated with an increased risk of morbidity and mortality, suggesting that too many transfusions may have a deleterious effect. In a recent randomized trial in preterm neonates with thrombocytopenia, the liberal transfusion group (receiving more platelet transfusions) had a significantly higher rate of death or major bleeding than the restrictive group (receiving less transfusions). In preterm neonates with anemia, the available evidence is also limited and controversial. Two large randomized controlled trials (ETTNO and TOP) are currently assessing the safety and effectiveness of liberal versus restrictive red blood cell transfusions. Results of these large two studies, including the long-term neurodevelopment outcome, are eagerly awaited. Until then, reduction of anemia of prematurity by implementation of effective preventive measures, such as delayed cord clamping and minimization of iatrogenic blood loss, remain of paramount importance.
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ANDRÁSI, Terézia B., Violetta KÉKESI, Anna BLÁZOVICS, István DÓBI, Gábor SZABÂ, and Alexander JUHÁSZ-NAGY. "ETA receptor blockade protects the small intestine against ischaemia/reperfusion injury in dogs via an enhancement of antioxidant defences." Clinical Science 103, s2002 (September 1, 2002): 59S—63S. http://dx.doi.org/10.1042/cs103s059s.
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The aim of the present study was to determine whether the ETA receptor antagonist LU135252 can protect the mesenterium against ischaemia/reperfusion (I/R) damage. Direct occlusion of the superior mesenteric artery was performed for 30min in two groups of dogs. Declamping was followed by 90min of reperfusion. Mesenteric release of ET-1 was studied in series 1 (n = 6). In series 2, 5min before cross-clamping, the treated group (n = 7) received an intravenous bolus of LU135252 (5mg/kg), whereas the control group (n = 6) was given vehicle. Mean arterial blood pressure and mesenteric blood flow were recorded. Mesenteric venous and systemic arterial serum lactate and glucose, plasma creatine kinase and free radical concentrations were determined at 15min intervals. Ischaemia for 30min induced a significant increase (P<0.05) in mesenteric ET-1 release (1594±526pg/min, compared with 343±258pg/min at baseline), which had returned to baseline after 20min of reperfusion. LU135252 administration significantly decreased mesenteric blood flow during ischaemia (204±23%) compared with controls (320±34%, P<0.05). In contrast, mesenteric blood flow was higher in the treated group (120±19% compared with 82±7%; P<0.05) after 90min of reperfusion. Mesenteric lactate production was reduced by ETA antagonist administration under ischaemia (0.77±0.02mmol/l) compared with controls (1.36±0.04mmol/l; P<0.01). Lower levels of venous creatine kinase were present in the treated group during ischaemia as well as after reperfusion (120±7% compared with 150±16%; P<0.01). Administration of LU135252 also improved the total scavenger capacity of the mesenteric bed during ischaemia [(15.9±3.9)×106 compared with (6.4±3.6)×106 relative light units; P<0.05] and early reperfusion [(8.7±3.1)×106 compared with (1.1±2.9)×106 relative light units]. Thus ET-1 is involved in I/R-induced disturbances in the intestine. LU135252 seems to counteract these changes, in part by increasing the antioxidant capacity of the mesenterium.
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Tihanov-Tănăsache, Daniel, Radu Ştefănoiu, Aurelia Binchiciu, and Emilia Binchiciu. "Experiments with the Purpose of Expanding the Loading Capacity of Standard Construction Grapples." Advanced Materials Research 1157 (February 2020): 182–87. http://dx.doi.org/10.4028/www.scientific.net/amr.1157.182.
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A grapple is a device that includes at least one gripping arrangement. The gripping arrangement is configured to grip and traverse objects so as to reach a desired location on site and to anchor it, therefore allowing the work to be carried out. [1] A method for controlling the fill volume of a grapple, such as a bulk-material crane grapple which includes at least one hoist-and-closure unit, may include adjusting the fill volume of the grapple is during the grapple closure process by adjusting/controlling the grapple hoist height. The grapple hoist speed and/or grapple hoist height may be the controlling parameter for the adjustment of the fill volume of the grapple. [2]Grapples geometric configuration is established by calculating the useful load mass. In the experiments performed in the present paper the load mass was 3000 kg. In exploitation, in cases where relatively low density materials, if compared to standard materials, are being moved/processed, changes to the volume capacity must be done; [3] changes that need to be correlated with the new materials and the exploitation conditions.The tractor attachment is a grapple assembly, and the grapple assembly kit includes a mounting assembly, a plurality of clamping units, and a plurality of support units. [4] A connection system for coupling an claw to a work vehicle includes a receiver assembly that needs to be implement and configured to a connector assembly of an arm of the work vehicle. [5]The solution developed by the authors consists in prolonging and consolidating the active elements of the grapple, by equipping it with additional elements that take and process load tensions, in the present case hard wood logs; and a consolidation and protection system that protects it from wear, that mostly appears when the hook crane repeatedly hits the ground in order to collect the deposited logs.The additional elements for handling and processing logs are made out of low alloyed steel, thus by configuring the tips we assure the good gliding of processed materials on the active/used surfaces. The self-protection system to wear is made out of boron micro-alloyed steel sheets that have hardness values up to 500 HB. Joining the grapple ensemble with specialized elements was performed through welding.
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Hays, S. R., and R. J. Alpern. "Inhibition of Na(+)-independent H+ pump by Na(+)-induced changes in cell Ca2+." Journal of General Physiology 98, no. 4 (October 1, 1991): 791–813. http://dx.doi.org/10.1085/jgp.98.4.791.
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Apical membrane H+ extrusion in the renal outer medullary collecting duct, inner stripe, is mediated by a Na(+)-independent H+ pump. To examine the regulation of this transporter, cell pH and cell Ca2+ were measured microfluorometrically in in vitro perfused tubules using 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein and fura-2, respectively. Apical membrane H+ pump activity, assayed as cell pH recovery from a series of acid loads (NH3/NH+4 prepulse) in the total absence of ambient Na+, initially occurred at a slow rate (0.06 +/- 0.02 pH units/min), which was not sufficient to account for physiologic rates of H+ extrusion. Over 15-20 min after the initial acid load, the rate of Na(+)-independent cell pH recovery increased to 0.63 +/- 0.09 pH units/min, associated with a steady-state cell pH greater than the initial pre-acid load cell pH. This pattern suggested an initial suppression followed by a delayed activation of the apical membrane H+ pump. Replacement of peritubular Na+ with choline or N-methyl-D-glucosamine resulted in an initial spike increase in cell Ca2+ followed by a sustained increase in cell Ca2+. The initial rate of Na(+)-independent cell pH recovery could be increased by elimination of the Na+ removal-induced sustained cell Ca2+ elevation by: (a) performing studies in the presence of 135 mM peritubular Na+ (1 mM peritubular amiloride used to inhibit basolateral membrane Na+/H+ antiport); (b) clamping cell Ca2+ low with dimethyl-BAPTA, an intracellular Ca2+ chelating agent; or (c) removal of extracellular Ca2+. Cell acidification induced a spike increase in cell Ca2+. The late acceleration of Na(+)-independent cell pH recovery was independent of Na+ removal and of the method used to acidify the cell, but was eliminated by prevention of the cell Ca2+ spike and markedly delayed by the microfilament-disrupting agent, cytochalasin B. This study demonstrates that peritubular Na+ removal results in a sustained elevation in cell Ca2+, which inhibits the apical membrane H+ pump. In addition, rapid cell acidification associated with a spike increase in cell Ca2+ leads to a delayed activation of the H+ pump. Thus, cell Ca2+ per se, or a Ca(2+)-activated pathway, can modulate H+ pump activity.
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Sorensen, Charlotte Mehlin, Paul Peter Leyssac, Max Salomonsson, Ole Skott, and Niels-Henrik Holstein-Rathlou. "ANG II-induced downregulation of RBF after a prolonged reduction of renal perfusion pressure is due to pre- and postglomerular constriction." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 286, no. 5 (May 2004): R865—R873. http://dx.doi.org/10.1152/ajpregu.00424.2003.
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Previous experiments from our laboratory showed that longer-lasting reductions in renal perfusion pressure (RPP) are associated with a gradual decrease in renal blood flow (RBF) that can be abolished by clamping plasma ANG II concentration ([ANG II]). The aim of the present study was to investigate the mechanisms behind the RBF downregulation in halothane-anesthetized Sprague-Dawley rats during a 30-min reduction in RPP to 88 mmHg. During the 30 min of reduced RPP we also measured glomerular filtration rate (GFR), proximal tubular pressure (Pprox), and proximal tubular flow rate (QLP). Early distal tubular fluid conductivity was measured as an estimate of early distal [NaCl] ([NaCl]ED), and changes in plasma renin concentration (PRC) over time were measured. During 30 min of reduced RPP, RBF decreased gradually from 6.5 ± 0.3 to 6.0 ± 0.3 ml/min after 5 min (NS) to 5.2 ± 0.2 ml/min after 30 min ( P < 0.05). This decrease occurred in parallel with a gradual increase in PRC from 38.2 ± 11.0 × 10-5 to 87.1 ± 25.1 × 10-5 Goldblatt units (GU)/ml after 5 min ( P < 0.05) to 158.5 ± 42.9 × 10-5 GU/ml after 30 min ( P < 0.01). GFR, Pprox, and [NaCl]ED all decreased significantly after 5 min and remained low. Estimates of pre- and postglomerular resistances showed that the autoregulatory mechanisms initially dilated preglomerular vessels to maintain RBF and GFR. However, after 30 min of reduced RPP, both pre- and postglomerular resistance had increased. We conclude that the decrease in RBF over time is caused by increases in both pre- and postglomerular resistance due to rising plasma renin and ANG II concentrations.
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Papanikolaou, Dimitra, Chris Savio, Mohammad A. Zafar, Leon Freudzon, Jinlin Wu, Mohamed Abdelbaky, Keith J. Pelletier, et al. "Left Atrial to Femoral Artery Full Cardiopulmonary Bypass: A Novel Technique for Descending and Thoracoabdominal Aortic Surgery." International Journal of Angiology 29, no. 01 (December 9, 2019): 019–26. http://dx.doi.org/10.1055/s-0039-3400479.
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AbstractLeft atrial-femoral artery (LA-FA) bypass with a centrifugal pump and no oxygenator is commonly used for descending and thoracoabdominal aortic (DTAA) operations, mitigating the deleterious effects of cross-clamping. We present our initial experience performing DTAA replacement under LA-FA (left-to-left) cardiopulmonary bypass (CPB) with an oxygenator. DTAA replacement under LA-FA bypass with an oxygenator was performed in 14 consecutive patients (CPB group). The pulmonary vein and femoral artery (or distal aorta) were cannulated and the full CPB machine were used, including oxygenator, roller pump, pump suckers, and kinetically enhanced drainage. The CPB group was compared with 50 consecutive patients who underwent DTAA replacement utilizing traditional LA-FA bypass without an oxygenator (LA-FA group). Perioperative data were collected and statistical analyses were performed. All CPB patients maintained superb cardiopulmonary stability. The pump sucker permitted immediate salvage and return of shed blood. Superb oxygenation was maintained at all times. High-dose full CPB heparin was reversed without difficulty. The CPB group required markedly fewer blood transfusions than the LA-FA group (2.21 vs. 5.88 units, p < 0.004). The 30-day mortality rate was 7.1% (n = 1) and there were no paraplegia cases in the CPB group versus 7 (14%) deaths and 3 (6%) paraplegia cases in the LA-FA group. Traditional LA-FA bypass without an oxygenator avoids high-dose heparin. In the present era, heparin reversal is more secure. Our experience finds that the novel application of LA-FA CPB with an oxygenator is safe and suggests improved hemodynamics (immediate return of shed blood) and a hemostatic advantage (avoidance of loss of coagulation factors in the cell saver).
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Attallah, Ahmed Rady, Shady Eid Al-Elwany, Mohammed A. K. Salama Ayyad, and Ali Mohammed Abdelwahab. "Early clinical outcome after right anterolateral thoracotomy as an alternative for median sternotomy for mitral valve replacement." Egyptian Cardiothoracic Surgeon 2, no. 2 (April 1, 2020): 47–54. http://dx.doi.org/10.35810/ects.v2i2.111.
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Background: The advantages of the right anterolateral thoracotomy (RALT) approach for mitral valve surgery over standard median sternotomy (MS) are still debatable. The objective of this study was to evaluate and compare the postoperative clinical outcome after RALT and MS for mitral valve replacement.
Methods: This prospective observational study included 40 patients who underwent mitral valve replacement between January 2016 and August 2018. Patients were assigned to two groups, the first group included 20 patients who had conventional median sternotomy approach and the second group included 20 patients who had right anterolateral thoracotomy with the complete cannulation and aortic cross-clamping conducted through the same incision.
Results: In comparison to MS, RALT had significantly higher cross-clamp time (77.7±16.1 vs 45.8±8.7 minutes, P < 0.01), total bypass time (105.2±12.7 vs 72.2±10.4 minutes, P < 0.01), and total operative time (287±41 vs 231±36 min, P < 0.01), in addition to significantly lower ventilation time (4.2±1.51 vs 6.1±1.84 hours, P < 0.01), blood loss (229±85 vs 335±137 ml), amount of blood transfusion (1.41±0.6 vs 2.19±1.1 units, P < 0.01), ICU stay duration (2.11±0.49 vs 2.78±0.82 days, P < 0.01), pain scores at 1st and 2nd postoperative days (5.67±0.79 vs 7.81±0.53, p < 0.01), and total hospital stay duration (7.2±1.3 vs 8.4±1.6 days, P = 0.01). Patients' satisfaction about their wound was significantly higher in RALT group compared to MS group (95% vs 30%, P < 0.01).
Conclusion: The RALT approach for mitral valve surgery could be a safe and effective approach when compared to median sternotomy. RALT could be associated with a reduction of blood loss, blood transfusion, wound infection, in addition to shorter ICU and hospital stay.
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Rouan, Fatima, Thomas W. White, Nkecha Brown, Aileen M. Taylor, Thomas W. Lucke, David L. Paul, Colin S. Munro, Jouni Uitto, Malcolm B. Hodgins, and Gabriela Richard. "trans-dominant inhibition of connexin-43 by mutant connexin-26: implications for dominant connexin disorders affecting epidermal differentiation." Journal of Cell Science 114, no. 11 (June 1, 2001): 2105–13. http://dx.doi.org/10.1242/jcs.114.11.2105.
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Dominant mutations of GJB2-encoding connexin-26 (Cx26) have pleiotropic effects, causing either hearing impairment (HI) alone or in association with palmoplantar keratoderma (PPK/HI). We examined a British family with the latter phenotype and identified a new dominant GJB2 mutation predicted to eliminate the amino acid residue E42 (ΔE42) in Cx26. To dissect the pathomechanisms that result in diverse phenotypes of dominant GJB2 mutations, we studied the effect of three Cx26 mutants (ΔE42, D66H and R75W) identified in individuals with PPK/HI, and another (W44C) present in individuals with non-syndromic HI on gap junctional intercellular communication. We expressed mutant Cx26 alone and together with the epidermal connexins Cx26, Cx37 and Cx43 in paired Xenopus oocytes, and measured the intercellular coupling by dual voltage clamping. Homotypic expression of each connexin as well as co-expression of wild-type (wt) Cx26/wtCx43 and wtCx26/wtCx37 yielded variable, yet robust, levels of channel activity. However, all four Cx26 mutants were functionally impaired and failed to induce intercellular coupling. When co-expressed with wtCx26, all four mutants suppressed the wtCx26 channel activity consistent with a dominant inhibitory effect. However, only those Cx26 mutants associated with a skin phenotype also significantly (P<0.05) inhibited intercellular conductance of co-expressed wtCx43, indicating a direct interaction of mutant Cx26 units with wtCx43. These results demonstrate, for the first time, a trans-dominant negative effect of Cx26 mutants in vitro. Furthermore, they support a novel concept suggesting that the principal mechanism for manifestation of dominant GJB2 mutations in the skin is their dominant interference with the function of wtCx43. This assumption is further corroborated by our finding that Cx26 and Cx43 focally colocalize at gap junctional plaques in affected skin tissue of two carriers of ΔE42.
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Denesyuk, Alexander I., Sergei E. Permyakov, Mark S. Johnson, Konstantin Denessiouk, and Eugene A. Permyakov. "System Approach for Building of Calcium-Binding Sites in Proteins." Biomolecules 10, no. 4 (April 11, 2020): 588. http://dx.doi.org/10.3390/biom10040588.
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We introduce five new local metal cation (first of all, Ca2+) recognition units in proteins: Clampn,(n−2), Clampn,(n−1), Clampn,n, Clampn,(n+1) and Clampn,(n+2). In these units, the backbone oxygen atom of a residue in position “n” of an amino acid sequence and side-chain oxygen atom of a residue in position “n + i” (i = −2 to +2) directly interact with a metal cation. An analysis of the known “Ca2+-bound niches” in proteins has shown that a system approach based on the simultaneous use of the Clamp units and earlier proposed One-Residue (OR)/Three-Residue (TR) units significantly improves the results of constructing metal cation-binding sites in proteins.
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JIAO, Zhiwei. "Research on Novel Clamping Unit's Working Principle of Injection Molding Machine." Journal of Mechanical Engineering 48, no. 10 (2012): 153. http://dx.doi.org/10.3901/jme.2012.10.153.
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Terazono, T., V. V. Luu, L. T. K. Do, M. Taniguchi, M. Takagi, and T. Otoi. "183 ULTRASONOGRAPHIC MONITORING OF CANINE OVARIES CLAMPED AT SUBCUTANEOUS SITE AFTER FOLLICLE-STIMULATING HORMONE TREATMENT." Reproduction, Fertility and Development 27, no. 1 (2015): 183. http://dx.doi.org/10.1071/rdv27n1ab183.
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Follicle-stimulating hormone (FSH) alone can induce oestrus in bitches, but few reports describe oestrous induction by FSH because pregnant mare serum gonadotrophin (PMSG) has been more successful than FSH for oestrus induction. Real-time ultrasonography can show canine ovarian follicle development, but no method can determine or predict ovulation accurately. Moreover, the ovary location and size complicate imaging. Using ultrasonography, we investigated FSH treatment stimulation of canine ovary follicles, with clamping of the ovaries at a subcutaneous site. Bilateral malacotomy of four 5-year-old Beagle bitches (mean weight 10.3 ± 2.0 kg) with normal oestrous cycles was done using a ventral flank abdominal approach with routine techniques and materials. Each ovary that maintained blood circulation from the suspensory ligament was clamped at a subcutaneous site through muscles of the abdomen. After about six months of bilateral malacotomy, four bitches at the anestrous (two bitches) and diestrous (two bitches) stages of the oestrous cycle were given 0.5 Armour units of FSH twice daily for 5 days. Examinations with ovarian ultrasonography with 7.5 MHz sector transducer, vaginal cytology, and serum concentrations of progesterone and oestradiol were performed daily from the day before the start of FSH treatment through 7 days after FSH treatment. After 15 days of ovarian examination, each bitch received the same FSH treatment twice continually at 15-day intervals. No serosanguineous vaginal discharge was observed during the ovarian examination. The concentrations of progesterone (<0.045–9.6 ng mL–1) and oestradiol (<9.7–81.4 pg mL–1) varied through all treatments. Comparison of the concentrations of progesterone (<0.045–7.6 ng mL–1) and oestradiol (<9.7–30.3 pg mL–1) at the start of FSH administration in each trial revealed that elevated concentrations of both progesterone and oestradiol were observed in the first treatment in 3 bitches. Regarding the second and third treatments, no elevation of concentration was found for progesterone or oestradiol. A new follicular growth was observed in 1 animal after the third FSH treatment, but no follicular growth was found for the other animals. No correlation was found between follicular development and the profile of either progesterone or oestradiol. Ultrasonography proved that FSH stimulation alone cannot induce follicular growth by a single treatment, but it might increase the levels of progesterone and oestradiol, which are not correlated with follicular development and oestrous cycles at the start of FSH treatment.
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Vigneswaran, Wickii T., and Charles Gruner. "Computer-Mediated Power Stapling for Anatomical Lung Resection: Experience in 100 Consecutive Cases." Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery 1, no. 6 (December 2006): 328–31. http://dx.doi.org/10.1097/01.imi.0000229891.91345.6e.
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Objectives Mechanical stapling is widely used for lung resection. Complications related to the stapling are few but not infrequent. This varies from complete disruption of the staples to incomplete sealing of vascular structures. A stapling platform that has a strong clamping force with precise and consistent staple formation suitable for thickness of tissue is likely to be an advance in existing devices and may reduce the complication rate. A new, computer-mediated power stapling is currently available for lung resections, with three types of digital loading units (DLU). Clinical data on its use are limited. We report our experience with this stapling platform (SurgASSIST) in our first 100 patients undergoing anatomic lung resection. Methods Fifty-four men and forty-six women (mean age, 64 ± 7 years) underwent anatomic lung resections, using a lateral, muscle-sparing mini-thoracotomy, during 2004 to 2005, with the SurgASSIST platform. Three types of DLUs were used for lung resection: a linear cutter, a right-angled vascular cutter, and a right-angled bronchial cutter. Observational data were collected prospectively on the operative procedure, type of staples used, duration of operation, chest tube drainage, and hospital length of stay. Results There were 83 lobectomies, 5 bilobectomies, 5 segmental resections, and 7 pneumonectomies. A total of 502 DLUs (mean, 5 per patient; 102 vascular, 91 bronchial, and 309 linear cutters) were used in this series. There were no major operative complications. The mean operating time was 136 ± 41 minutes. One bronchial dehiscence and one incomplete sealing of the pulmonary vein in the staple line were observed. In one patient, the linear cutter could not be opened in the automatic setting. There were 15% misreads by the computer on the DLU or their inserts. There was one hospital death unrelated to the stapling. Twenty additional complications included prolonged chest tube drainage (n = 8), reoperations (n = 2), atrial fibrillation (n = 5), hemothorax (n = 1), chylothorax (n = 1), C-dif colitis (n = 1), myocardial ischemia (n = 1), and incarcerated ventral hernia (n = 1). The median hospital length of stay was 5 days (range, 3 to 26 days) and the median length of chest tube drainage was 3 days (1 to 22 days). Conclusions Our experience shows that the computer-mediated power stapling of lung parenchyma and hilar structures during anatomic resection is safe and reproducible.
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Aung, Fleur M., and Benjamin Lichtiger. "A Simple Quick Method of Draining Red Cells from Granulocyte Concentrates Ex Vivo without the Addition of Hetastarch after Granulocytapheresis." Blood 136, Supplement 1 (November 5, 2020): 17. http://dx.doi.org/10.1182/blood-2020-141448.
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Introduction Granulocytapheresis from healthy volunteer donors are performed regularly at our institution to treat severely neutropenic leukemia/SCT patients with overwhelming bacterial/fungal infections. 500 to 750 mL of Hespan® (6% hetastarch in 0.9% sodium chloride injection) with citrate anticoagulant is administered by aseptic addition to the input line of the centrifugation apparatus at a ratio of 1:13 to venous whole blood. The traditional method of gravity sedimentation of Granulocyte concentrates (GC) is the addition of 50 cc of 6% Hydroxyethyl starch in ACD anticoagulant which results in RBC volume reduction to < 5ml (range acceptable for transfusion to ABO incompatible recipients according to AABB standards). The method is time consuming, tedious and adds additional HES to the product. We streamlined the process by allowing the sedimented red cells to drain via gravity upon completion of the apheresis procedure without the addition of Hetastarch. Method: GCs are obtained from prescreened eligible (meet AABB/FDA guidelines) family/friends of the patients. G-CSF is administered as a fixed dose of 480 mcg (donors < 250 lbs.) or as 2 doses of 300/480 mcg (donors > 250 lbs) plus 8 mg of dexamethasone (without history of cataracts) 12 hours prior to the collection. 30 ml of TriCitrasol Anticoagulant (46.7% Trisodium citrate) is added to 500 ml of 6% Hetastarch in 0.9% Sodium Chloride Injection for IV use only and not more than 1000 ml is used in a single GC apheresis procedure. Our current practice is to test all O blood group donors for Anti-A Isoagglutinin titers. Cut off titers are set at <128. GCs from group O donors with Anti-A titers > 128 are drained of red cells if the recipient is non-O. For pediatric patients, our practice is to drain all GC products regardless of ABO compatibility between donor and recipient. Process: Upon completion of the Granulocytaheresis, the GC collection bag is left undisturbed hanging on the IV pole leaving all slips clamps attached. Red cells collected during the apheresis procedure settle at the base the collection bag. The collection line of the GC collection bag is clamped distal to the attachment of the sterile barrier filter inclusive of the sample bulb assembly. The clamp proximal to the sample bulb assembly needs to be left clamped. The collection bag is then sterile docked to a transfer bag (the plasma bag from the IDL set can be used) to create a closed sterile system. Two hemostats clamps are placed, one close to the inlet port of the collection bag and the other close to the sterile dock of the transfer bag. The clamps are opened slowly and the sedimented red cells are allowed to slowly drain into the transfer bag. Pressure using two fingers may be used to create a funnel to express the sedimented red cells into the port from the GC unit. When the desired amount of red cells are expressed into the transfer bag the process is stopped. The transfer bag is then removed by clamping and a relatively clean GC product is now available for transfusion. The entire process takes approximately 10-15 minutes. The GC bag is then sampled via the incorporated sample bulbs for the bag count, then labelled ready for release for transfusion. Results: We reviewed the results of six drained GCs by this method; the median Bag RBC was 0.8 x10e6/uL (range 0.06 - 0.23), Bag Hgb 0.8 g/dL (range 0.5-1.0) and Bag Hematocrit 0.7% (range 0.6-2.6). The median Bag WBC count was 10.6 x 10e10 (range 5.8 to 15.1), median bag volume 641 mL (range 462-774) and median volume processed 10526 ml (range 8800-12175 mL). We achieved our goal of reducing the red cells to <2 ml, providing a GC with more than the minimum yield (1.0 x 10e10) required according to AABB standards and also the availability of a GC product within 2 hours of completion for transfusion. Discussion: The use of the newer Apheresis machine allows for efficient removal of the targeted component and monitors/adjusts the depth at which the cells are collected within the Buffy coat layer based on the desired hematocrit of the collected product. Our practice is to collect a relatively clean GC product where there is less than 2 mL of red cell contamination in the GC unit. However, this is not always achieved and the GC units do have to be drained. Approximately 10-25 mL of red cells are drained depending on the collection and the GC units drained in this manner are comparable to the GCs drained after the addition of 50 cc of Hetastarch to the GC product. Disclosures No relevant conflicts of interest to declare.
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"Selection of hydraulic clamping units simplified." Aircraft Engineering and Aerospace Technology 73, no. 2 (April 2001). http://dx.doi.org/10.1108/aeat.2001.12773bab.067.
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Mariano, Richard G., Alyssa Grace S. Gablan, and Frederick Ray I. Gomez. "Elimination of Non-stick on Leads Defect through Re-designed WCTP." Journal of Engineering Research and Reports, July 17, 2021, 22–26. http://dx.doi.org/10.9734/jerr/2021/v20i1017385.
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This paper presents the reformation and fabrication resolved on the wire clamp and top plate (WCTP) design to eliminate the presence of lead finger bouncing resulting to high rejection of non-stick on leads (NSOL). Problem experienced was that the hollow or half-etched portion of the leadframe at the top and bottom units caused its bouncing effect. With the aim to improve localized massive NSOL defect, WCTP has been modified to provide positive bias to support its hollow part or the half-etched part of the leadframe at the top and bottom of the units. The re-designed WCTP was fabricated, extending its clamping with enhanced vacuum on top and bottom rows. The implementation of the improved WCTP design reduced the defect with 88 % improvement with the defect reduction during the lot runs.
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"Umbilical Cord Blood." International Journal of Women’s Health Care 1, no. 1 (July 22, 2016). http://dx.doi.org/10.33140/ijwhc.01.01.05.
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Umbilical cord blood (UCB) is widely considered as a potential alternative to bone marrow for haematopoietic stem cells. Efforts on UCB research have now taken a step further with the establishment of numerous cord blood banks throughout the world. In 15 months (from December 1999 to February 2001) we obtained 863 cord blood units by withdrawing residual blood from the placenta.The method of blood collection consisted of puncturing, with an 18-gauge needle, the umbilical cord vein and withdrawing the blood into a sterile bag immediately after clamping and newborn assistance. The blood was collected when the placenta was still in utero. Analysis of the blood was also performed to exclude any bacterial contamination. Among them 429 were collected from newborns delivered vaginally (Group 1) and 434 were collected from caesarean sections (Group 2). In this study we evaluated the volume of blood collected and the number of CD34+ cells contained in the foetal cord blood and we demonstrated that these two parameters were similar between the two groups; The higher median volume of blood collected from infant delivered through a caesarean section seems mainly due to the different clamping time rather than to the kind of delivery.
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Ibrahim, Tamer Hamed. "Efficacy of tranexamic acid in reducing blood loss, blood and blood products requirements in Cesarian sections for patients with placenta accreta." Ain-Shams Journal of Anesthesiology 11, no. 1 (December 2019). http://dx.doi.org/10.1186/s42077-019-0051-9.
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Abstract Background Placenta accreta is an obstetric emergency and the main cause of maternal morbidity and mortality due to the associated bleeding and coagulopathy. Tranexamic acid has been widely used to decrease blood loss in trauma patients and patients with postpartum hemorrhage. We aimed at studying the effect of tranexamic acid in reducing blood loss and blood transfusion in patients with placenta accreta. Methods In a double-blinded randomized controlled study, 46 patients were recruited and divided into two groups, Group A is the tranexamic group where patients received 10 mg/kg tranexamic acid after cord clamping and continued on tranexamic infusion 10 mg/kg/h till the end of the surgery. Group B is the placebo where patients received normal saline instead. Primary outcome was the amount of intraoperative blood loss, and other outcomes included the number of blood and blood products transfused intraoperative and in the first 24 h postoperative, the immediate postoperative Hb level, platelet count, and coagulation profile. Data were collected, coded, tabulated, and then analyzed using Minitab® 16.1.0 statistics software package. Variables were presented as mean and standard deviation and analyzed using unpaired t test. Any difference with p value < 0.05 was considered statistically significant. Results Amount of intraoperative blood loss was significantly less in the tranexamic group 2232 ± 1204 ml compared to the placebo group 3405 ± 1193 ml (p value 0.002), and patients in the tranexamic group received less units of packed red blood cells, fresh frozen plasma, and platelets compared to those in the placebo group (4.2 ± 1.9 vs 6.1 ± 2.2 with p value 0.003, 3.4 ± 1.3 vs 4.2 ± 1.2 with P value 0.036 and 4.8 ± 2.1 vs 6.2 ± 2.4 with p value 0.041, respectively). There was no statistically significant difference in the first postoperative Hb level, platelet count, and coagulation profile between the two groups; however, the amount of blood and products transfused in the first 24 h postoperative were significantly less in the tranexamic group Conclusion Tranexamic acid infusion was effective in reducing intraoperative blood loss and intraoperative and postoperative blood and blood products’ transfusion.