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Allali, Noureddine, Hassan Afif, Martine Couturier y Laurence Van Melderen. "The Highly Conserved TldD and TldE Proteins of Escherichia coli Are Involved in Microcin B17 Processing and in CcdA Degradation". Journal of Bacteriology 184, n.º 12 (15 de junio de 2002): 3224–31. http://dx.doi.org/10.1128/jb.184.12.3224-3231.2002.
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ABSTRACT Microcin B17 (MccB17) is a peptide antibiotic produced by Escherichia coli strains carrying the pMccB17 plasmid. MccB17 is synthesized as a precursor containing an amino-terminal leader peptide that is cleaved during maturation. Maturation requires the product of the chromosomal tldE (pmbA) gene. Mature microcin is exported across the cytoplasmic membrane by a dedicated ABC transporter. In sensitive cells, MccB17 targets the essential topoisomerase II DNA gyrase. Independently, tldE as well as tldD mutants were isolated as being resistant to CcdB, another natural poison of gyrase encoded by the ccd poison-antidote system of plasmid F. This led to the idea that TldD and TldE could regulate gyrase function. We present in vivo evidence supporting the hypothesis that TldD and TldE have proteolytic activity. We show that in bacterial mutants devoid of either TldD or TldE activity, the MccB17 precursor accumulates and is not exported. Similarly, in the ccd system, we found that TldD and TldE are involved in CcdA and CcdA41 antidote degradation rather than being involved in the CcdB resistance mechanism. Interestingly, sequence database comparisons revealed that these two proteins have homologues in eubacteria and archaebacteria, suggesting a broader physiological role.
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Chung, Kwang Hyun, Young Sook Park, Sang Bong Ahn y Byoung Kwan Son. "Radiation protection effect of mobile shield barrier for the medical personnel during endoscopic retrograde cholangiopancreatography: a quasi-experimental prospective study". BMJ Open 9, n.º 3 (marzo de 2019): e027729. http://dx.doi.org/10.1136/bmjopen-2018-027729.
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ObjectiveTo investigate the effectiveness of radiation protection offered by a newly designed mobile shield barrier for medical personnel during endoscopic retrograde cholangiopancreatography (ERCP).DesignQuasi-experimental prospective study.SettingERCP procedures conducted between October 2016 and June 2017 at a single secondary referral hospital that performs approximately 250 therapeutic ERCP procedures annually.InterventionsThe mobile shield barrier was a custom-made 2 mm Pb shielding plate (width: 120 cm, height: 190 cm) with a 0.5 mm Pb window (width: 115 cm, height: 60 cm) on its upper part was used. Four wheels were attached to the bottom to allow easy moving.Primary and secondary outcome measuresThe radiation doses were measured during ERCP using personal thermoluminescence dosimetry (TLD) badges on both sides of the mobile shield barrier (patient’s side: TLD1 and medical staff’s side: TLD2). The radiation doses were also measured on the outer surface of the thyroid shield of the endoscopist (TLD3), and on the chest area inside the protective apron of the endoscopist (TLD4) and the main assistant (TLD5). The TLD was changed and reported once every 3 months. The radiation dose measured by TLD badges were compared.ResultsDuring the study period, a total of 128 ERCP procedures were performed. The mean fluoroscopy time per procedure was 244.9±257.0 s and the mean number of digital radiographs per procedure was 3.7±1.0. TLD1 (outside the barrier) had a mean radiation dose of 26.85±3.47 mSv and all the other TLDs (inside the barrier) had less than 1 mSv (p<0.001). In the post hoc analysis, the difference between TLD1 and others showed a statistical significance; however, there were no significant differences between the TLDs inside the barrier.ConclusionOur mobile shield barrier was useful to reduce the radiation exposure of medical personnel during ERCP.
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Zhang, Xin, Zhengqun Li, Yanxiang Zhao, Xilan Cheng, Yang Liu, Shihong Zhang y Junfeng Liu. "Crystal Structure of a Putative Modulator of Gyrase (TldE) from Thermococcus kodakarensis". Crystals 9, n.º 2 (19 de febrero de 2019): 107. http://dx.doi.org/10.3390/cryst9020107.
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TldD and TldE proteins interact and form a complex to degrade unfolded peptides. The gene Tk0499 from Thermococcus kodakarensis encoded a putative modulator of gyrase (TkTldE). Although TldE genes were common in bacteria and archaea, the structural basis on the evolution of proteins remained largely unknown. Here, the three-dimensional structure of TkTldE was determined by X-ray diffraction. Crystals were acquired by the sitting-drop vapor-diffusion method. X-ray diffraction data from crystals were collected at 2.35 Å. The space group and unit-cell parameters suggested that there were two molecules in the asymmetric unit. Our results showed that TkTldE forms a homodimer, which contained anti-parallel β-strands and a pair of α-helices. Comparison of the structures of TldE and TldD showed that despite their high sequence similarity, TldE lacked the conserved HExxxH and GxC motif in which two His and a Cys residues bound a metal ion. Taken together, these results provided insight into the structural information of this class of TldE/TldD.
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Hu, Yongmei, Nan Peng, Wenyuan Han, Yuxia Mei, Zhengjun Chen, Xu Feng, Yun Xiang Liang y Qunxin She. "An archaeal protein evolutionarily conserved in prokaryotes is a zinc-dependent metalloprotease". Bioscience Reports 32, n.º 6 (15 de octubre de 2012): 609–18. http://dx.doi.org/10.1042/bsr20120074.
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A putative protease gene (tldD) was previously identified from studying tolerance of letD encoding the CcdB toxin of a toxin–antidote system of the F plasmid in Escherichia coli. While this gene is evolutionarily conserved in archaea and bacteria, the proteolytic activity of encoded proteins remained to be demonstrated experimentally. Here we studied Sso0660, an archaeal TldD homologue encoded in Sulfolobus solfataricus by overexpression of the recombinant protein and characterization of the purified enzyme. We found that the enzyme is active in degrading azocasein and FITC–BSA substrates. Protease inhibitor studies showed that EDTA and o-phenanthroline, two well-known metalloprotease inhibitors, either abolished completely or strongly inhibited the enzyme activity, and flame spectrometric analysis showed that a zinc ion is a cofactor of the protease. Furthermore, the protein forms disulfide bond via the Cys416 residue, yielding protein dimer that is the active form of the enzyme. These results establish for the first time that tidD genes encode zinc-containing proteases, classifying them as a family in the metalloprotease class.
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AHARON, D. C., J. HEUKELS y R. F. BUNTSMA. "Orthomanual therapy as treatment for suspected thoracolumbar disc disease in dogs ABSTRACT." Journal of the Hellenic Veterinary Medical Society 66, n.º 1 (27 de diciembre de 2017): 31. http://dx.doi.org/10.12681/jhvms.15581.
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According to the principles of veterinary orthomanual medicine, vertebral misalignments are associated with intervertebral disc disease in dogs. Manual correction of these vertebral misalignments are presumed to contribute to successful recovery. The objective of this retrospective study was to evaluate the effects of veterinary orthomanual therapy (VOT) in 261 dachshunds with suspected thoracolumbar intervertebral disc disease (TLDD). Effect of treatment was assessed using a retrogradeneurological status classification. From one clinic’s 2003-2008 medical records, 261 dachshunds with suspected TLDD met the inclusion criteria. Individual data included signalement and history, orthomanual aspects and neurological evaluations before treatment and at 2 weeks, 3 months and 6 months. Telephone interviews with owners were conducted one year after the initial treatment. The initial neurological status according to Griffiths ‘82 grading, was grade I in 115 animals (44%), grade II in 59 animals (23%), grade III in 27 animals (10%), grade IV in 52 animals (20%) and grade V in 8 animals (3%). Two weeks after the first treatment, 111 animals (55%) with initial grade I, II or III and two animals (3%) with initial grade IV or V had improved from their initial grade to a neurologically normal state; within 6 months of the initial treatment this full recovery was observed in 154 animals (77 %) with initial grade I, II or III and 27 animals (45%) with initial grade IV or V. Of the initially non-ambulatory dogs, 82% recovered to an ambulatory state. Of the owners, 89% evaluated the treatment as successful after 1 year. Most (78%) of the animals underwent a single VOT treatment, and the most commonly misaligned vertebrae were T12, T13 and L1. Veterinary orthomanual therapy is a conservative treatment method, which is minimally stressful for the animal and inexpensive. VOT combined with cage rest seems to be effective in treating TLDD in dachshunds. The results of this study demonstrate that veterinary orthomanual therapy might be considered an adjunct modality for the non-surgical treatment of dachshunds with intervertebral disc disease. A prospective controlled clinical trial is needed to further examine its efficacy.
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Ghilarov, Dmitry, Marina Serebryakova, Clare E. M. Stevenson, Stephen J. Hearnshaw, Dmitry S. Volkov, Anthony Maxwell, David M. Lawson y Konstantin Severinov. "The Origins of Specificity in the Microcin-Processing Protease TldD/E". Structure 25, n.º 10 (octubre de 2017): 1549–61. http://dx.doi.org/10.1016/j.str.2017.08.006.
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Hölscher, Tina y Helmut Görisch. "Knockout and Overexpression of Pyrroloquinoline Quinone Biosynthetic Genes in Gluconobacter oxydans 621H". Journal of Bacteriology 188, n.º 21 (25 de agosto de 2006): 7668–76. http://dx.doi.org/10.1128/jb.01009-06.
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ABSTRACT In Gluconobacter oxydans, pyrroloquinoline quinone (PQQ) serves as the cofactor for various membrane-bound dehydrogenases that oxidize sugars and alcohols in the periplasm. Proteins for the biosynthesis of PQQ are encoded by the pqqABCDE gene cluster. Our reverse transcription-PCR and promoter analysis data indicated that the pqqA promoter represents the only promoter within the pqqABCDE cluster of G. oxydans 621H. PQQ overproduction in G. oxydans was achieved by transformation with the plasmid-carried pqqA gene or the complete pqqABCDE cluster. A G. oxydans mutant unable to produce PQQ was obtained by site-directed disruption of the pqqA gene. In contrast to the wild-type strain, the pqqA mutant did not grow with d-mannitol, d-glucose, or glycerol as the sole energy source, showing that in G. oxydans 621H, PQQ is essential for growth with these substrates. Growth of the pqqA mutant, however, was found with d-gluconate as the energy source. The growth behavior of the pqqA mutant correlated with the presence or absence of the respective PQQ-dependent membrane-bound dehydrogenase activities, demonstrating the vital role of these enzymes in G. oxydans metabolism. A different PQQ-deficient mutant was generated by Tn5 transposon mutagenesis. This mutant showed a defect in a gene with high homology to the Escherichia coli tldD gene, which encodes a peptidase. Our results indicate that the tldD gene in G. oxydans 621H is involved in PQQ biosynthesis, possibly with a similar function to that of the pqqF genes found in other PQQ-synthesizing bacteria.
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Vobruba, Simon, Zdenek Kamenik, Stanislav Kadlcik y Jiri Janata. "N-Deacetylation in Lincosamide Biosynthesis Is Catalyzed by a TldD/PmbA Family Protein". ACS Chemical Biology 15, n.º 8 (6 de agosto de 2020): 2048–54. http://dx.doi.org/10.1021/acschembio.0c00224.
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Vorland, Colby, Michelle Bohan Brown, Michelle Cardel y Andrew Brown. "Traffic Light Diets Per Se Have Limited Evidence for Effectiveness on Childhood Obesity: A Review". Current Developments in Nutrition 4, Supplement_2 (29 de mayo de 2020): 1697. http://dx.doi.org/10.1093/cdn/nzaa063_095.
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Abstract Objectives The “traffic light diet” (TLD; or “stop light diet” among other names) categorizes foods into ‘green’, ‘yellow’, or ‘red’ groups to consume without restriction, in moderation, or minimally, respectively. It is often a component of childhood interventions targeting weight-related outcomes. The Academy of Nutrition and Dietetics Evidence Analysis Library assigned TLDs Grade I evidence in 2006 for pediatric weight management, but none of the studies reviewed tested the TLD in isolation. We conducted a review of the effect of TLDs on obesity-related outcomes in children and definitions among different implementations of TLDs. Methods We searched PubMed up to September 2019 for interventions using the TLD with obesity-related anthropometric outcomes. Studies were screened in duplicate, and treatment characteristics extracted. Additional studies were identified by screening references. Using a convenience sample of texts from the original TLD creators, Indiana University vending, a new pediatric weight loss app, and an online resource, we assessed how definitions of TLDs compare. Results Our search identified 386 abstracts, 5 of which were interventions that included the TLD and weight-related outcomes. Three of these were randomized controlled trials, and none studied the TLD in isolation outside of multicomponent interventions. We then focused on 4 foundational TLD articles that were repeatedly cited. One of these isolated the TLD from the multicomponent intervention but found no statistical effect of the diet or interaction of diet with other factors for weight-related outcomes. In the sample of TLD implementations, substantial differences were apparent in how foods were classified among green, yellow, and red groups, such as avocados, nuts, figs/fig cookies, and peanut butter. Conclusions There is insufficient evidence supporting TLDs as a unique, isolatable factor in improving weight-related outcomes in children. This does not necessarily mean that TLDs are ineffective, as they have been incorporated into successful interventions. A standardization of TLD definitions (consistently categorizing foods and whether the term ‘TLD’ is meant to include other components of an intensive lifestyle intervention) is needed to make comparisons of effectiveness going forward. Funding Sources The authors received no funding for this specific work.
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Rahman, M. Obaidur, Md Ashraful Hoque, Md Shakilur Rahman y Afia Begum. "Responses of LiF Thermoluminescence Dosimeters to Diagnostic 60Co Teletherapy Beams". Bangladesh Journal of Medical Physics 8, n.º 1 (10 de septiembre de 2017): 14–21. http://dx.doi.org/10.3329/bjmp.v8i1.33930.
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Thermoluminescence Dosimeter (TLD) is used as an ionizing radiation detector in the field of clinical radiotherapy, diagnostic radiology, personal radiation monitoring as well as in environmental radiation dosimetry. The sensitivity of all the TLDs is not the same even though the manufacturer produced them in the same batch. The response of TLD at various doses is also not always linear. In the present study fifty-seven rod shaped LiF TLDs had been irradiated by doses of 50cGy, 100cGy, 150cGy and 200cGy using 60Co teletherapy unit of Dhaka Medical College (Alcyon II, CGR, McV, France). The TLDs were placed in the grooves of a slab phantom and then covered by a 0.5cm thick plexiglass sheet. The phantom was then irradiated in the reference condition (10x10cm2 field size, 80cm SSD). After irradiation, readout of TLDs was done using a Harshaw TLD reader (Model 3500). Measurements were performed three times for each dose value and their average was taken. For convenience all fifty-seven TLDs were divided into nineteen groups. Grouping was done according to the response of the TLDs for a fixed dose value. In a particular group of TLDs, variation of the response of the dosimeters is the smallest one. The dose (cGy) response (nC) linearity curve of TLDs for each of the nineteen groups showed to be very close to unity.Bangladesh Journal of Medical Physics Vol.8 No.1 2015 14-21
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Yeh, Po-Hung, Shao-Hua Chung y Bang-Fuh Chen. "Multiple TLDs on Motion Reduction Control of the Offshore Wind Turbines". Journal of Marine Science and Engineering 8, n.º 6 (24 de junio de 2020): 470. http://dx.doi.org/10.3390/jmse8060470.
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This study explores the damping effects of tuned liquid dampers (TLDs) on a monopile offshore wind turbine (OWT). The fluid–solid coupling of ANSYS was used to simulate the damping effect of a TLD on the structures. The environmental conditions refer to the IEC-61400-3 and the Design Load Case (DLC) 1.2 for the annual average environmental conditions and DLC 6.2 for the 50-year regression period, and the extreme environmental conditions were used in the study. The turbulent wind field simulation was performed by TurbSim, and the load of wind waves on structures was generated by FAST, which were all developed by the NREL (National Renewable Energy Laboratory). In addition to wind and waves, the seismic force was also considered. The cylindrical TLD was located above the rotor nacelle assembly (RNA). A TLD has different damping effects when acting under wind, wave, and earthquake loads, respectively. The effect of the TLD regarding motion reduction on the OWT under coupled wind, wave, and seismic loads was studied. This study also designed a simple experiment to verify the correctness of the numerical simulation results. Fatigue analysis shows that multi-layer TLDs can extend the fatigue life (37%) of an OWT. In addition, under extreme environmental load conditions, multi-layer TLDs have a better vibration damping performance than single-layer TLDs. The study demonstrates that multi-layer TLDs can be considered as a vibration reduction damper for OWTs.
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Tsibulskaya, Darya, Olga Mokina, Alexey Kulikovsky, Julia Piskunova, Konstantin Severinov, Marina Serebryakova y Svetlana Dubiley. "The Product of Yersinia pseudotuberculosis mcc Operon Is a Peptide-Cytidine Antibiotic Activated Inside Producing Cells by the TldD/E Protease". Journal of the American Chemical Society 139, n.º 45 (31 de octubre de 2017): 16178–87. http://dx.doi.org/10.1021/jacs.7b07118.
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Herrati, Ammar, Mourad Bourouina y Karima Khalal-Kouache. "Investigation of TLD-700 energy response to low energy x-ray encountered in diagnostic radiology". Open Physics 14, n.º 1 (1 de enero de 2016): 150–58. http://dx.doi.org/10.1515/phys-2016-0016.
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AbstractThe aim of thiswork is to study the energy dependence of thermoluminescent dosimeter (TLD-700) for low energy X-ray beams encountered in conventional diagnostic radiology. In the first step, we studied some characteristics (reproducibility and linearity) of TLD-700 chips using a 137Cs source, and selected TLD chips with reproducibility better than 2.5%. Then we determined TLD-700 energy response for diagnostic radiology X-ray qualities, and investigated its influence on air kerma estimate. A maximum deviation of 60% can be obtained if TLDs are calibrated for 137Cs radiation source and used in diagnostic radiology fields. However, this deviation became less than 20% if TLDs chips are calibrated for the reference x-ray radiation quality RQR5 (recommended by the IEC 61267 standard). Consequently, we recommend calibrating this kind of TLDdetector with RQR5 diagnostic radiology X-ray quality. This method permits to obtain a good accuracy when assessing the entrance dose in diagnostic radiology procedures.
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Tuong, Bui Pham Duc, Phan Duc Huynh, Tan-Trung Bui y Vasilis Sarhosis. "Numerical Analysis of the Dynamic Responses of Multistory Structures Equipped with Tuned Liquid Dampers Considering Fluid-Structure Interactions". Open Construction and Building Technology Journal 13, n.º 1 (18 de noviembre de 2019): 289–300. http://dx.doi.org/10.2174/1874836801913010289.
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Aims: The paper analyzes the effectiveness of tuned liquid damper in controlling the vibration of high rise building. The new contribution is considering the fluid-structure interaction of a water tank as a Tuned Liquid Dampers (TLD). Background: Currently, buildings are being built higher and higher, which requires TLDs to be larger as well. Therefore, the fluid pressure acting on the tank wall is more significant. In previous studies of liquid sloshing in TLDs, researchers simply ignored the effect of liquid pressure acting on the tank walls by making the assumption that the tanks are rigid. Currently, the failure of a tank because of FSI occurs regularly, so this phenomenon cannot be ignored when designing the tanks in general and TLDs in particular. Objective: To investigate the thickness of the tank wall affect to the TLD mechanism. Method: Numerical method was used for this research. Results: A TLD could be easy to design; however one could not bypass the fluid-structure interaction by assuming the tank wall is rigid. Conclusion: This kind of damper is very good to mitigate the dynamic response of structrure.
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Wang, Zhe, Liang Cao, Filippo Ubertini y Simon Laflamme. "Numerical Investigation and Design of Reinforced Concrete Shear Wall Equipped with Tuned Liquid Multiple Columns Dampers". Shock and Vibration 2021 (28 de febrero de 2021): 1–19. http://dx.doi.org/10.1155/2021/6610811.
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The tuned liquid multiple column damper (TLMCD) is a variation of the tuned liquid column damper (TLCD) that includes multiple vertical columns. A new damping system that embeds TLMCDs within reinforced concrete shear wall systems, termed tuned liquid wall damper (TLWD), is proposed, augmenting the traditional structural component with energy dissipation capabilities. The objective of this study is to assess energy mitigation and strength trade-offs in designing TLWDs and demonstrating the promise of TLWD systems in tall buildings through vertically distributed applications. This is done by investigating the performance of the proposed TLWD through the finite element model (FEM) of a simplified representation of a 42-story building equipped with the multifunctional component. A strength model for the TLWD is developed to empower faster performance evaluation on more complex models. Results from the FEM are used to validate the strength model and show that the model could be used conservatively in assessing strength performance. Design considerations are discussed based on the simplified representation. In particular, to improve mitigation performance while maintaining strength, it is found that a single-layer arrangement of the vertical columns is preferred, while distributing the inertia among a higher number of smaller columns. The proposed TLWD is numerically evaluated on a more realistic system consisting of a multi-degrees-of-freedom representation of the 42-story building under stochastic wind excitation. Simulation results demonstrate that the TLWD, used in a vertically distributed configuration through the building, could be used to mitigate vibrations, outperforming a traditional TLCD system with geometric constraints under 20 design wind realization. Results from the numerical simulations also confirmed the design considerations established through the simplified representation.
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Guberina, Nika, Saravanabavaan Suntharalingam, Kai Naßenstein, Michael Forsting, Jens Theysohn, Axel Wetter y Adrian Ringelstein. "Verification of organ doses calculated by a dose monitoring software tool based on Monte Carlo Simulation in thoracic CT protocols". Acta Radiologica 59, n.º 3 (15 de junio de 2017): 322–26. http://dx.doi.org/10.1177/0284185117716199.
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Background The importance of monitoring of the radiation dose received by the human body during computed tomography (CT) examinations is not negligible. Several dose-monitoring software tools emerged in order to monitor and control dose distribution during CT examinations. Some software tools incorporate Monte Carlo Simulation (MCS) and allow calculation of effective dose and organ dose apart from standard dose descriptors. Purpose To verify the results of a dose-monitoring software tool based on MCS in assessment of effective and organ doses in thoracic CT protocols. Material and Methods Phantom measurements were performed with thermoluminescent dosimeters (TLD LiF:Mg,Ti) using two different thoracic CT protocols of the clinical routine: (I) standard CT thorax (CTT); and (II) CTT with high-pitch mode, P = 3.2. Radiation doses estimated with MCS and measured with TLDs were compared. Results Inter-modality comparison showed an excellent correlation between MCS-simulated and TLD-measured doses ((I) after localizer correction r = 0.81; (II) r = 0.87). The following effective and organ doses were determined: (I) (a) effective dose = MCS 1.2 mSv, TLD 1.3 mSv; (b) thyroid gland = MCS 2.8 mGy, TLD 2.5 mGy; (c) thymus = MCS 3.1 mGy, TLD 2.5 mGy; (d) bone marrow = MCS 0.8 mGy, TLD 0.9 mGy; (e) breast = MCS 2.5 mGy, TLD 2.2 mGy; (f) lung = MCS 2.8 mGy, TLD 2.7 mGy; (II) (a) effective dose = MCS 0.6 mSv, TLD 0.7 mSv; (b) thyroid gland = MCS 1.4 mGy, TLD 1.8 mGy; (c) thymus = MCS 1.4 mGy, TLD 1.8 mGy; (d) bone marrow = MCS 0.4 mGy, TLD 0.5 mGy; (e) breast = MCS 1.1 mGy, TLD 1.1 mGy; (f) lung = MCS 1.2 mGy, TLD 1.3 mGy. Conclusion Overall, in thoracic CT protocols, organ doses simulated by the dose-monitoring software tool were coherent to those measured by TLDs. Despite some challenges, the dose-monitoring software was capable of an accurate dose calculation.
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van der Zee, Esther N., Jelle L. Epker, Jan Bakker, Dominique D. Benoit y Erwin J. O. Kompanje. "Treatment Limitation Decisions in Critically Ill Patients With a Malignancy on the Intensive Care Unit". Journal of Intensive Care Medicine 36, n.º 1 (13 de agosto de 2020): 42–50. http://dx.doi.org/10.1177/0885066620948453.
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Background: Treatment limitation decisions (TLDs) on the ICU can be challenging, especially in patients with a malignancy. Up-to-date literature regarding TLDs in critically ill patients with a malignancy admitted to the ICU is scarce. The aim was to compare the incidence of written TLDs between patients with an active malignancy, patients with a malignancy in their medical history (complete remission, CR) and patients without a malignancy admitted unplanned to the ICU. Methods: We conducted a retrospective cohort study in a large university hospital in the Netherlands. We identified all unplanned admissions to the ICU in 2017 and categorized the patients in 3 groups: patients with an active malignancy (study population), with CR and without a malignancy. A TLD was defined as a written instruction not to perform life-saving treatments, such as CPR in case of cardiac arrest. A multivariate binary logistic regression analysis was used to identify whether having a malignancy was associated with TLDs. Results: Of the 1046 unplanned admissions, 125 patients (12%) had an active malignancy and 76 (7.3%) patients had CR. The incidence of written TLDs in these subgroups were 37 (29.6%) and 20 (26.3%). Age (OR 1.03; 95% CI 1.01 -1.04), SOFA score at ICU admission (OR 1.11; 95% CI 1.05 -1.18) and having an active malignancy (OR 1.75; 95% CI 1.04-2.96) compared to no malignancy were independently associated with written TLDs. SOFA scores on the day of the TLD were not significantly different in patients with and without a malignancy. Conclusions: This study shows that the presence of an underlying malignancy is independently associated with written TLDs during ICU stay. Patients with CR were not at risk of more written TLDs. Whether this higher incidence of TLDs in patients with a malignancy is justified, is at least questionable and should be evaluated in future research.
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Raubenheimer, R., B. Spangenberg, G. Van Jaarsveld, A. Koller, C. De Vries, C. P. Herbst, C. A. Willemse y G. Joubert. "Do dose area product meter measurements reflect radiation doses absorbed by health care workers?" South African Journal of Radiology 8, n.º 2 (9 de junio de 2004): 24. http://dx.doi.org/10.4102/sajr.v8i2.129.
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This study determined the correlation between radiation doses absorbed by health care workers and dose area product meter (DAP) measurements at Universitas Hospital, Bloemfontein. The DAP is an instrument which accurately measures the radiation emitted from the source. The study included the interventional radiologists, radiographers and nurses associated with radiological intervention procedures during the period 1 August 2003 - 31 August 2003. The amount of radiation produced during every procedure was measured by a dose area product meter (DAP) and routinely recorded. The absorbed doses received by health care workers were measured using a thermoluminescent dose meter (TLD). The TLDs were analysed and recorded at the end of each week. Health care workers wore TLDs on the following areas: forehead, thyroid (attached under thyroid guard), and abdomen (worn under lead jacket). A strong positive correlation (r = 0.9, p = 0.0374) was found between the radiographers’ head TLD and DAP meter readings. All other correlations between TLD and DAP readings were not statistically significant. Strong positive correlations were found between the TLD readings of the radiologists’ and nurses’ bodies, the nurses’ and radiographers’ bodies and the radiologists’ and the radiographers’ bodies, all of which were statistically significant.
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Holguín-Veras, José y Ellen Thorson. "Trip Length Distributions in Commodity-Based and Trip-Based Freight Demand Modeling: Investigation of Relationships". Transportation Research Record: Journal of the Transportation Research Board 1707, n.º 1 (enero de 2000): 37–48. http://dx.doi.org/10.3141/1707-05.
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Commodity-based and vehicle-trip-based freight demand modeling is discussed. The characteristics of the trip length distributions (TLDs) are examined, defined in terms of tons, as required in commodity-based modeling, and in vehicle trips, as required in trip-based modeling. With data used from a major transportation study in Guatemala, the TLDs are estimated for both tons and vehicle trips. The analysis revealed that ( a) the shape of the TLDs depends upon the type of movements being considered; ( b) TLDs defined in terms of tonnage differ significantly from those defined in terms of vehicle trips; ( c) TLDs for different types of vehicles, transporting similar commodities, reflect the range of use of each type of vehicle; ( d) though tons TLDs and vehicle TLDs are different, the relationship between them seems to follow a systematic pattern that, if successfully identified, would enable transportation planners to estimate one type of TLD given the other; and ( e) major freight generators affect the shape of the TLDs, so complementary models may be needed to provide meaningful depictions of freight movements.
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Kaloop, Mosbeh R., Jong Wan Hu y Yasser Bigdeli. "The Performance of Structure-Controller Coupled Systems Analysis Using Probabilistic Evaluation and Identification Model Approach". Shock and Vibration 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/5482307.
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This study evaluates the performance of passively controlled steel frame building under dynamic loads using time series analysis. A novel application is utilized for the time and frequency domains evaluation to analyze the behavior of controlling systems. In addition, the autoregressive moving average (ARMA) neural networks are employed to identify the performance of the controller system. Three passive vibration control devices are utilized in this study, namely, tuned mass damper (TMD), tuned liquid damper (TLD), and tuned liquid column damper (TLCD). The results show that the TMD control system is a more reliable controller than TLD and TLCD systems in terms of vibration mitigation. The probabilistic evaluation and identification model showed that the probability analysis and ARMA neural network model are suitable to evaluate and predict the response of coupled building-controller systems.
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Yuan, Zhan-Sheng, Chih-Cheng Chen, Yu-Ying Lie y Cheng-Fu Yang. "Using phosphor to enhance the efficiency of commercial solar cells". Modern Physics Letters B 33, n.º 14n15 (28 de mayo de 2019): 1940041. http://dx.doi.org/10.1142/s0217984919400414.
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The non-rare-earth phosphor Ca2ZnMoO6 has a luminescence of 375–655 nm and emits near-white light. This study investigated it as a down-shifting layer to improve the efficiency of commercial flexible solar cells. The first structure was a solar cell/thick-film Ca2ZnMoO6 phosphor layer (TLDU device); a controlled light source was shone on the top, and UV light was shone on the bottom. The second structure was a solar cell/thick-film Ca2ZnMoO6 phosphor layer with an Al reflective layer (TLDR device), and only a controlled light source was used. We compared the power output efficiencies of the two structures with the efficiency of a control device. When the [Formula: see text]–[Formula: see text] properties of the three different devices were measured, the [Formula: see text] value underwent no apparent change, but the [Formula: see text] increased in the TLDU and TLDR devices. These results suggest that if placed on the bottom surface of commercial solar cells, Ca2ZnMoO6 phosphor could improve their efficiency.
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Sobotka, Piotr, Bartłomiej Kliś, Zuzanna Baranowska, Katarzyna Wołoszczuk, Katarzyna Rutkowska y Tomasz Woliński. "Efficient reading of thermoluminescent dosimeter signals using semiconductor detectors". Nukleonika 65, n.º 4 (1 de diciembre de 2020): 223–27. http://dx.doi.org/10.2478/nuka-2020-0034.
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AbstractThe aim of this experimental work was to examine whether semiconductor photodetectors may be applied for the efficient reading of thermoluminescent dosimeter (TLD) signals. For this purpose, a series of experiments have been performed at the Department of Physics, Warsaw University of Technology, in cooperation with the Central Laboratory for Radiological Protection (CLOR). Specifically, the measurement system proposed here has been designed to detect a signal from TLDs that use a semiconductor detector operating in conditions analogous to those met when using commercial devices equipped with a classic photomultiplier. For the experimental tests, the TLDs were irradiated with a beam of 137Cs radiation in the accredited Laboratory for Calibration of Dosimetric and Radon Instruments. Eventually, a comparison of the results obtained with a semiconductor detector (ID120) and a commercial TLD reader with a photomultiplier tube (RADOS) were made.
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Li, Hong-Nan, Ting-Hua Yi, Qin-Yang Jing, Lin-Sheng Huo y Guo-Xin Wang. "Wind-Induced Vibration Control of Dalian International Trade Mansion by Tuned Liquid Dampers". Mathematical Problems in Engineering 2012 (2012): 1–21. http://dx.doi.org/10.1155/2012/848031.
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This paper focuses on the wind-induced vibration control of the Dalian international trade mansion (DITM) by using the tuned liquid dampers (TLDs). To avoid the intensive computationally demanding problem caused by tens of thousand of degrees of freedom (DOF) of the structure in the numerical analysis, the three-dimension finite element model of the DITM is first simplified to the equivalent series multi-DOF system. The wind loading is subsequently simulated by the Davenport model according to the structural environmental condition where the actual samples of wind speed are measured. Following that, the shallow- and deep-water wave theories are applied to model the liquid sloshing inside TLDs, the tank sizing, and required water depth, and numbers of TLDs are given according to the numerical results of different cases. Comparisons between uncontrolled and controlled displacement and acceleration responses of the DITM under wind forces show that the designed shallow tank has higher efficiency than the deep one, which can effectively reduce the structural response amplitudes and enhance the comfortableness of the mansion. The preliminary TLD design procedure presented in this paper could be applied as a reference to the analysis and design of the wind-induced vibration for high-rise buildings using the TLD.
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You, Jang Youl, Ki Pyo You y Young Moon Kim. "Evaluation on Aerodynamic Across-Wind Response for a Tall Building Using Tuned Liquid Column Damper". Advanced Materials Research 919-921 (abril de 2014): 1361–70. http://dx.doi.org/10.4028/www.scientific.net/amr.919-921.1361.
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Tuned liquid column damper (TLCD) is more advantageous in terms of space than TLD so that it is far more advantageous when it comes to installation on the actual building. To investigate the effectiveness of a tuned liquid column damper (TLCD) in mitigation wind-induced excitation motion of a tall building, aeroelastic experiments were conducted. A 1: 200 scaled model of an aeroelastic tall building was built, and TLCD models of mass ratio of 1.5% and 3%, respectively, were designed and tested with the aeroelastic model. As such, this study has installed TLCD with different lengths of horizontal pipes at the top most floor of realistic model. This is similar to the actual structure, centred on the interval where the vortex-induced vibration of low wind speed occurs, by conducting aeroelastic model tests in suburban areas and the vibration response in across-wind direction shall be found in order to figure out the wind vibration control effect according to various types (horizontal length, mass ratio) changes.
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Sun, Jie, Gong Yu Li, Lang Liu y Qing Bo Liu. "The TLCD U-Tube Liquid Sloshing Finite Element Modal Analysis". Advanced Materials Research 694-697 (mayo de 2013): 350–53. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.350.
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The paper studies the dynamic characteristics of liquid sloshing in TLD rectangular container, and verifies the feasibility of finite element numerical simulation, by the theory and finite element numerical simulation of liquid sloshing. Similarly employing the verified numerical simulation method, we get the sloshing frequency and mode of liquid sloshing in TLCD u-tube container.
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Kapuciánová, Michaela y Daniela Ekendahl. "POSTAL TLD AUDIT OF HETEROGENEITY CORRECTIONS IN RADIOTHERAPY IN THE CZECH REPUBLIC". Radiation Protection Dosimetry 186, n.º 2-3 (diciembre de 2019): 373–76. http://dx.doi.org/10.1093/rpd/ncz234.
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Abstract In the Czech Republic, a more advanced version of postal audit in radiotherapy (RT) is available. It covers dose measurements with thermoluminescent dosemeters (TLD) in more complex conditions of irradiation, when dose distribution is affected by heterogeneities in the irradiated volume. Relative deviation between doses measured with TLDs and doses stated by RT centre should not exceed 3%. During 2015–2017, all Czech RT centres equipped with modern linear accelerators were subjected to this more advanced TLD audit. A total of 70% of participants complied with the limit of 3% in the first round of this audit.
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Kaneko, S. y M. Ishikawa. "Modeling of Tuned Liquid Damper With Submerged Nets". Journal of Pressure Vessel Technology 121, n.º 3 (1 de agosto de 1999): 334–43. http://dx.doi.org/10.1115/1.2883712.
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An analytical model for describing the effectiveness of tuned liquid damper (TLD) with submerged nets for suppressing horizontal vibration of structures is proposed. Dissipation energy due to the liquid motion under sinusoidal excitation is calculated based on nonlinear shallow water wave theory. In particular, the effects of hydraulic resistance produced by nets installed in a tank on the performance of TLDs are examined. The results of dissipation energy theoretically obtained are confirmed by experiments. To show the effectiveness of the proposed analytical model for TLD-structure interaction problems, the case in which TLD with nets is installed on top of a pylon of a cable-stayed bridge is described and the calculated results are compared with the actual experimental data. In the calculation, it is shown that the optimal damping factor, as is the case for tuned mass dampers (TMD), can be produced by the nets, and the effectiveness of TLD with nets are demonstrated.
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Villanueva, Andrew y Braden Goddard. "LOSS OF TLD SIGNAL DUE TO HIGH TEMPERATURE ENVIRONMENTAL CONDITIONS". Radiation Protection Dosimetry 187, n.º 1 (17 de junio de 2019): 17–20. http://dx.doi.org/10.1093/rpd/ncz130.
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Abstract While it is known that temperatures above 100°C have an effect on the reported dose of a TLD, it is less widely known what the susceptibility is to temperatures below 100°C, temperatures humans could reasonably expect to be exposed to. With the expanding nuclear industry in climates with more extreme temperatures, (e.g. United Arab Emirates and Saudi Arabia) the effect on a TLD if left on a dashboard of a car need to be evaluated. This research experimentally determined the extent of this thermal susceptibility by testing a range of high temperatures, 40°C – 90°C. The experimental results found that there is a statistically significant reduction in TLD-100H (natLiF:Mg,Cu,P) light output for TLDs there were exposed to temperatures as low as 40°C for 8 hour durations and 50°C for 2 hour durations. There is statistical difference in TLD-100H light output for elevated temperature durations of 8 hours compared to 24 hours.
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Gómez, Jessica, Mario J. Simirgiotis, Beatriz Lima, Carlos Gamarra-Luques, Jorge Bórquez, Duilio Caballero, Gabriela Egly Feresin y Alejandro Tapia. "UHPLC–Q/Orbitrap/MS/MS Fingerprinting, Free Radical Scavenging, and Antimicrobial Activity of Tessaria absinthiodes (Hook. & Arn.) DC. (Asteraceae) Lyophilized Decoction from Argentina and Chile". Antioxidants 8, n.º 12 (28 de noviembre de 2019): 593. http://dx.doi.org/10.3390/antiox8120593.
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The decoction of Tessaria absinthioides is used in traditional medicine of South America as hypocholesterolemic, balsamic, and expectorant; but it is also useful for the prevention of hepatitis, renal insufficiency, and diabetes, and is used as digestive. A lyophilized decoction from the aerial parts of this plant (TLD) collected in San Juan (TLDSJ) and Mendoza (TLDM) provinces (Argentina) and one collection from Antofagasta, Chile (TLDCH) were characterized regarding antioxidant and antibacterial activities, phenolics and flavonoids content, and ultrahigh resolution liquid chromatography Orbitrap MS analysis UHPLC–PDA–OT-MS/MS metabolite profiling. The antioxidant properties were carried out "in vitro" using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and trolox equivalent antioxidant activity (TEAC) methods, ferric-reducing antioxidant power (FRAP), and lipoperoxidation in erythrocytes (LP). The antibacterial activity was evaluated following the Clinical and Laboratory Standards Institute (CLSI) rules. TLDSJ, TLDM, and TLDCH displayed a strong DPPH scavenging activity (EC50 = 42, 41.6, and 43 µg/mL, respectively) and inhibition of lipoperoxidation in erythrocytes (86–88% at 250 µg TLD/mL), while a less effect in the FRAP and TEACantioxidant assays was found. Additionally, the decoctions showed a content of phenolics compounds of 94 mg gallic acid equivalents (GAE)/g, 185 GAE/g, and 64 GAE/g, for TLDSJ, TLDM, and TLDCH samples, respectively. Regarding the flavonoid content, the Chilean sample was highlighted with 19 mg quercetin equivalents (QE)/g. In this work, several phenolic compounds, including sesquiterpenes, flavonoids, and phenolic acids, were rapidly identified in TLDSJ, TLDM, and TLDCH extracts by means UHPLC–PDA–OT-MS/MS for the first time, which gave a first scientific support to consider this medicinal decoction from both countries as a valuable source of metabolites with antioxidant effects, some with outstanding potential to improve human health.
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Radaideh, Khaldoon M., Laila M. Matalqah, A. A. Tajuddin, W. I. Fabian Lee, S. Bauk y E. M. Eid Abdel Munem. "Development and evaluation of a Perspex anthropomorphic head and neck phantom for three dimensional conformal radiation therapy (3D-CRT)". Journal of Radiotherapy in Practice 12, n.º 3 (22 de abril de 2013): 272–80. http://dx.doi.org/10.1017/s1460396912000453.
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AbstractPurposesTo design, construct and evaluate an anthropomorphic head and neck phantom for the dosimetric evaluation of 3D-conformal radiotherapy (3D-CRT) dose planning and delivery, for protocols developed by the Radiation Therapy Oncology Group (RTOG).Materials and methodsAn anthropomorphic head and neck phantom was designed and fabricated using Perspex material with delineated planning target volumes (PTVs) and organs at risk (OARs) regions. The phantom was imaged, planned and irradiated conformally by a 3D-CRT plan. Dosimetry within the phantom was assessed using thermoluminescent dosimeters (TLDs). The reproducibility of phantoms and TLD readings were checked by three repeated identical irradiations. Subsequent three clinical 3D-CRT plans for nasopharyngeal patients have been verified using the phantom. Measured doses from each dosimeter were compared with those acquired from the treatment planning system (TPS).ResultsPhantom's measured doses were reproducible with <3·5% standard deviation between the three TLDs’ repeated measurements. Verification of three head and neck 3D-CRT patients’ plans was implemented, and good agreement between measured values and those predicted by TPS was found. The percentage dose difference for TLD readings matched those corresponding to the calculated dose to within 4%.ConclusionThe good agreement between predicted and measured dose shows that the phantom is a useful and efficient tool for 3D-CRT technique dosimetric verification.
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Liuzzi, Raffaele, Consiglia Piccolo, Vittoria D’Avino, Stefania Clemente, Caterina Oliviero, Laura Cella y Mariagabriella Pugliese. "Dose–Response of TLD-100 in the Dose Range Useful for Hypofractionated Radiotherapy". Dose-Response 18, n.º 1 (1 de enero de 2020): 155932581989408. http://dx.doi.org/10.1177/1559325819894081.
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Purpose: The aim of the study was to exploit the feasibility of thermoluminescent dosimeters (TLDs) in radiation therapy techniques in which high dose per fraction is involved. Methods: Dose–response of TLD-100 (LiF: Mg, Ti) was investigated in both 6-MV photon and 6-MeV electron beams. The element correction factor (ECF) generation method was applied to check the variability of the TLDs response. Two batches of 50 TLDs were divided into groups and exposed in the dose range 0 to 30 Gy. Regression analysis was performed with both linear and quadratic models. For each irradiation beam, the calibration curves were obtained in 3 dose range 0 to 8 Gy, 0 to 10 Gy, and 0 to 30 Gy. The best-fitting model was assessed by the Akaike Information Criterion test. Results: The ECF process resulted a useful tool to reduce the coefficients of variation from original values higher than 5% to about 3.5%, for all the batches exposed. The results confirm the linearity of dose–response curve below the dose level of 10 Gy for photon and electron beam and the supralinear trend above. Conclusion: The TLDs are suitable dosimeters for dose monitoring and verification in radiation treatment involving dose up to 30 Gy in a single fraction.
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D’Avino, Vittoria, Francesco Tommasino, Stefano Lorentini, Giuseppe La Verde y Mariagabriella Pugliese. "The Performance of LiF:Mg-Ti for Proton Dosimetry within the Framework of the MoVe IT Project". Applied Sciences 11, n.º 17 (6 de septiembre de 2021): 8263. http://dx.doi.org/10.3390/app11178263.
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Proton therapy represents a technologically advanced method for delivery of radiation treatments to tumors. The determination of the biological effectiveness is one of the objectives of the MoVe IT (Modeling and Verification for Ion Beam Treatment Planning) project of the National Institute for Nuclear Physics (INFN) CSN5. The aim of the present work, which is part of the project, was to evaluate the performance of the thermoluminescent dosimeters (TLDs-100) for dose verification in the proton beam line. Four irradiation experiments were performed in the experimental room at the Trento Proton Therapy Center, where a 150 MeV monoenergetic proton beam is available. A total of 80 TLDs were used. The TLDs were arranged in one or two rows and accommodated in a specially designed water-equivalent phantom. In the experimental setup, the beam enters orthogonally to the dosimeters and is distributed along the proton beam profile, while the irradiation delivers doses of 0.8 Gy or 1.5 Gy in the Bragg peak. For each irradiation stage, the depth–dose curve was determined by the TLD readings. The results showed the good performance of the TLDs-100, proving their reliability for dose recordings in future radiobiological experiments planned within the MoVe IT context.
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Ghosh, Aparna Dey, Soumi Bhattacharyya y Anuja Roy. "On the Seismic Performance of Elevated Water Tanks and their Control Using TLDs". Key Engineering Materials 569-570 (julio de 2013): 270–77. http://dx.doi.org/10.4028/www.scientific.net/kem.569-570.270.
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The post-earthquake function of elevated water tank structures so as respond to the civil water requirements is of extreme significance. These structures are, however, extremely vulnerable to seismic conditions and there has been substantial damage/failure of several such structures during major earthquakes. A review of the damage and performance of some elevated water tanks subjected to earthquakes is presented in this paper. An investigation is also made on the seismic vibration control of elevated water tank structures by using Tuned Liquid Dampers (TLDs). A frequency domain formulation for the transfer function of the elevated water tank with attached TLDs is developed. Numerical studies on a reinforced concrete elevated water tank with shaft type support are carried out. The effect of detuning on the performance of the TLDs due to the change in the structural frequencies resulting from the fluctuating water level in the water tank is also examined. Results indicate that it is possible to design a fairly robust and effective TLD system for the seismic vibration mitigation of the considered elevated water tank.
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Nazaroh, Nazaroh. "KAJIAN ANALISIS KETIDAKPASTIAN TLD POSTAL IAEA/WHO SEBAGAI STANDAR PROGRAM AUDIT DOSIS". Jurnal Standardisasi 11, n.º 2 (28 de julio de 2009): 73. http://dx.doi.org/10.31153/js.v11i2.634.
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<p>The International Atomic Energy Agency (IAEA) and World Health Organization (WHO) operate the IAEA/WHO TLD postal dose audit programme using thermoluminescence dosimeter (TLDs) for Secondary Standard<br />Dosimetry Laboratory (SSDL) and user every year. As National Reference Laboratory in the field of radiation metrology, PTKMR – BATAN always participates in the postal dose audit programme on therapy level for 60Co<br />beam. On the postal dose audit programme, the uncertainties in the dose determination from TLD measurements have been evaluated by IAEA, which is comprises of uncertainties in the calibration coefficient of the TLD system<br />and uncertainties in factors correcting for dose response non linearity, fading of TL signal, energy response, and influence of TLD holder. The individual uncertainties then have been combined to estimate the total uncertaintiy in<br />the dose evaluated from TLD measurements. The combined relative standard uncertainty in the dose determined from TLD measurements has been estimated to be 1.2% for irradiation with 60Co gamma rays and 1.6% for<br />irradiation with high-energy X-rays. Results from irradiations by Bureau Internationale des Poids et Mesures (BIPM), Primary Standard Dosimetry Laboratory (PSDL), and SSDL compare favourably with the estimated<br />uncertainties, whereas TLD results of radiotherapy centres show higher standard deviations than those derived theoretically. This paper presented the result of TLD postal dose audit for 60Co beam owned by PTKMR-BATAN<br />in the year of 2006-2008.</p>
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Kartubi, Nazaroh, Assef Firnando Firmansyah, Pardi Pardi y Caecilia Tuti Budiantari. "Preparation for Eye Lens Dose Assessment at CSTRM-NNEA". SciMedicine Journal 2, n.º 1 (1 de marzo de 2020): 30–37. http://dx.doi.org/10.28991/scimedj-2020-0201-5.
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Because of the negative impact of radiation on the eye lens and the changes recommended by the International Commission on Radiological Protection (ICRP) 103 (2007) from 150 to 20 mSv (2 rem, the Regulation of BAPETEN Head No. 4 (2013) article 56 give the instruction that Monitoring of eye lens dose should be implemented starting from March 13, 2016, more intensive around the eye lens. To prepare eye lens dose assessment, The Center for Safety Technology and Radiation Metrology (CSTRM) - NNEA study the response of TLD-700H against the X-ray: N (80), N (100) and N (120) energies (usually used in the interventional radiology). Goals and objectives of this study were to obtain the response/calibrated TLD-700H which is traceable to the international system (SI) and TLD-700H can be used for an eye lens dose assessment in Indonesia. Twenty-one TLDs were irradiated with seven dosage variations (0.1; 0.5; 1; 5; 10; 15; 20) mSv at the Secondary Standard Dosimetry Laboratory (SSDL) - Jakarta. After being stored for 24 hours, the TLD were read by using TLD-Reader. The Dosimeter Response, R against doses of X-ray were: R(N80) = 34.595x + 0.1262; R² = 0.9986; R(N100) = 24.484x + 1.1357; R² = 0.9993; and R(N120) = 27.908x - 5.1065; R² = 0.9971. R: correlation coefficient, x: doses; These calibration responses can be used for eye lens dose assessment in Indonesia.
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Rahman, Mohammad Sohelur, Aleya Begum, Md Rezaul Karim Khan, Md Ashraful Hoque y M. M. Mahfuz Siraz. "Occupational Exposure to Ionizing Radiation in Interventional Cardiology Practices in Bangladesh during 2010-2014". Malaysian Journal of Medical and Biological Research 3, n.º 2 (31 de diciembre de 2016): 63–68. http://dx.doi.org/10.18034/mjmbr.v3i2.407.
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Objective: The objective of this study is to assess, analyze and discuss the occupational exposure to ionizing radiation in interventional cardiology practices in Bangladesh for the last 5-year periods.
Method: Each year, about 100 workers working in interventional cardiology departments of big hospitals in Dhaka City were monitored using Harshaw Thermoluminescent Dosimeters (TLDs) for quarterly basis. The effective dose of the occupational workers were measured using Two Harshaw TLD Readers (one is manual TLD reader, model-4500, and another is automatic TLD reader, model 6600 plus).
Finding: The average annual effective dose (about 80 % workers) in interventional cardiology practices were <2mSv in 2010-2014 and no monitored workers were found to have received an occupational exposure >50 mSv in a single year or >100 mSv in a 5 year period. The status and trends in occupational exposure demonstrate that radiation protection conditions at the majority of the workplace were adequate. Despite that, further optimization is necessary due to large variations observed in the maximum individual doses over the 5-year periods.
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PAN, LUNG-FA, YINGYI LE, YU-CHEN YEN, JUI-HUNG WENG, CHIEN-YI CHEN, CHUN-CHIEH LIANG y LUNG-KWANG PAN. "OPTIMIZING THE TLD-100H READOUT SYSTEM UNDER VARIOUS RADIOACTIVE I-131 DOSES VIA THE REVISED TAGUCHI DYNAMIC QUALITY LOSS FUNCTION". Journal of Mechanics in Medicine and Biology 20, n.º 10 (diciembre de 2020): 2040024. http://dx.doi.org/10.1142/s0219519420400242.
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The TLD-100H readout system performance under various radioactive I-131 exposure doses was optimized by four key factors via the revised Taguchi dynamic quality loss function. Taguchi dynamic analysis and the orthogonal array reorganizing the essential factors are crucial for the optimization of the thermoluminescent dosimeter (TLD) readout system given strict criteria of multiple irradiated environments and long-term exposure for calibrated TLDs. Accordingly, 96 TLD-100H chips were selected and randomly categorized into three batches with eight groups (four TLD chips in each group). Four factors, namely (1) initial temperature, (2) heating rate, (3) maximal temperature, and (4) TLD preheat time before reading were organized into eight combinations according to Taguchi suggestion, whereas each factor was preset at two levels. All 96 [Formula: see text] chips were put in three concentric circles with 30, 60, and 90 cm radii for 48 h, surrounding the radioactive 150[Formula: see text]mCi ([Formula: see text][Formula: see text]MBq) I-131 capsule and exposed to the cumulative doses of 88.2, 18.6, and 8.6[Formula: see text]mSv for the respective radii, accordingly. The TLD readings obtained from each group were analyzed to derive the sensitivity, coincidence, and reproducibility, then those were reorganized to draw four fish-bone-plots for the optimization. The optimal option for the TLD readout system implied the combination of A1 (a [Formula: see text]C initial temperature), B1 (a [Formula: see text]C/s heating rate), C1 (a [Formula: see text]C maximal temperature), and D2 (a 15[Formula: see text]s preheat time), which was further verified by the follow-up measurements. The dominant factors were A (initial temperature) and B (heating rate), whereas C (maximal temperature) and D (preheat time) were minor and provided negligible contributions to the system performance optimization.
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Ackermann, Nikolaus, Maximilian Tiller, Gisela Anding, Andreas Roggenkamp y Jürgen Heesemann. "Contribution of Trimeric Autotransporter C-Terminal Domains of Oligomeric Coiled-Coil Adhesin (Oca) Family Members YadA, UspA1, EibA, and Hia to Translocation of the YadA Passenger Domain and Virulence of Yersinia enterocolitica". Journal of Bacteriology 190, n.º 14 (16 de mayo de 2008): 5031–43. http://dx.doi.org/10.1128/jb.00161-08.
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ABSTRACT The Oca family is a novel class of autotransporter-adhesins with highest structural similarity in their C-terminal transmembrane region, which supposedly builds a beta-barrel pore in the outer membrane (OM). The prototype of the Oca family is YadA, an adhesin of Yersinia enterocolitica and Yersinia pseudotuberculosis. YadA forms a homotrimeric lollipop-like structure on the bacterial surface. The C-terminal regions of three YadA monomers form a barrel in the OM and translocate the trimeric N-terminal passenger domain, consisting of stalk, neck, and head region to the exterior. To elucidate the structural and functional role of the C-terminal translocator domain (TLD) and to assess its promiscuous capability with respect to transport of related passenger domains, we constructed chimeric YadA proteins, which consist of the N-terminal YadA passenger domain and C-terminal TLDs of Oca family members UspA1 (Moraxella catarrhalis), EibA (Escherichia coli), and Hia (Haemophilus influenzae). These constructs were expressed in Y. enterocolitica and compared for OM localization, surface exposure, oligomerization, adhesion properties, serum resistance, and mouse virulence. We demonstrate that all chimeric YadA proteins translocated the YadA passenger domain across the OM. Y. enterocolitica strains producing YadA chimeras or wild-type YadA showed comparable binding to collagen and epithelial cells. However, strains producing YadA chimeras were attenuated in serum resistance and mouse virulence. These results demonstrate for the first time that TLDs of Oca proteins of different origin are efficient translocators of the YadA passenger domain and that the cognate TLD of YadA is essential for bacterial survival in human serum and mouse virulence.
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Puchalska, Monika. "Modelling and measurements of distributions in an adult human phantom undergoing proton scanning beam radiotherapy: lung- and prostate-located tumours". Radiation and Environmental Biophysics 60, n.º 2 (2 de marzo de 2021): 243–56. http://dx.doi.org/10.1007/s00411-021-00895-w.
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AbstractProton radiotherapy has been shown to offer a significant dosimetric advantage in cancer patients, in comparison to conventional radiotherapy, with a decrease in dose to healthy tissue and organs at risk, because the bulk of the beam energy is deposited in the Bragg peak to be located within a tumour. However, it should be kept in mind that radiotherapy of cancer is still accompanied by adverse side effects, and a better understanding and improvement of radiotherapy can extend the life expectancy of patients following the treatment of malignant tumours. In this study, the dose distributions measured with thermoluminescent detectors (TLDs) inside a tissue-equivalent adult human phantom exposed for lung and prostate cancer using the modern proton beam scanning radiotherapy technique were compared. Since the TLD detection efficiency depends on the ionization density of the radiation to be detected, and since this efficiency is detector specific, four different types of TLDs were used to compare their response in the mixed radiation fields. Additionally, the dose distributions from two different cancer treatment modalities were compared using the selected detectors. The measured dose values were benchmarked against Monte Carlo simulations and available literature data. The results indicate an increase in the lateral dose with an increase of the primary proton energy. However, the radiation quality factor of the mixed radiation increases by 20% in the vicinity to the target for the lower initial proton energy, due to the production of secondary charged particles of low-energy and short range. For the cases presented here the MTS-N TLD detector seems to be the most optimal tool for dose measurements within the target volume, while the MCP-N TLD detector, due to an interplay of its enhanced thermal neutron response and decreased detection efficiency to highly ionising radiation, is a better choice for the out-of-field measurements. The pairs of MTS-6 and MTS-7 TLDs used also in this study allowed for a direct measurement of the neutron dose equivalent. Before it can be concluded that they offer an alternative to the time-consuming nuclear track detectors, however, more research is needed to unambiguously confirm whether this observation was just accidental or whether it only applies to certain cases. Since there is no universal detector, which would allow the determination of the dosimetric quantities relevant for risk estimation, this work expands the knowledge necessary to improve the quality of dosimetry data and might help scientists and clinicians in choosing the right tools to measure radiation doses in mixed radiation fields.
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Murthy, K. V. R. "Applications of TLDs in Radiation Dosimetry". Defect and Diffusion Forum 341 (julio de 2013): 211–30. http://dx.doi.org/10.4028/www.scientific.net/ddf.341.211.
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An increasing amount of public interest in environmental monitoring programmes is being focused on the environmental impact of radiation arising from nuclear power operations and the corresponding detection of slight variations in the natural radiation background. The primary objective of individual monitoring for external radiation is to assess, and thus limit, radiation doses to individual workers. Supplementary objectives are to provide information about the trends of these doses and about the conditions in places of work and to give information in the event of accidental exposure. Depending on the kind of radiation hazard, the ICRP recommended maximum permissible dose (MPD) values. These are the maximum dose equivalent values, which are not expected to cause appreciable body injury to a person during his lifetime. Thermoluminescent Dosimetry (TLD) has been developed during 1960-70 for various applications in medicine and industry. TLD, the most advanced and most intensively studied integrating dosimeter system, has now reached the stage at which it may replace or supplement film dosimetry. TLD systems are widely applied to environmental monitoring programmes near nuclear installations. TLD systems with high reproducibility in the milli roentgen dose range are required in order to measure exposures equal to that resulting from an exposure rate of 10μR h-1 during field periods of from several days up to a year. A brief list of applications specific to radiation oncology is given here. In radiation oncology dosimetric accuracy demanded is of the order of 2-5%. TLDs offer a clear solution since their precision meets this criteria. Contents
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Barros, Silvia y Geehyun Kim. "Response assessment of a new albedo neutron dosimeter". International Journal of Modern Physics: Conference Series 48 (enero de 2018): 1860111. http://dx.doi.org/10.1142/s2010194518601114.
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The use of thermoluminescent dosimeters (TLDs) by personnel who work in radiation-rich environments is required by law. However, many professionals prefer to use Electronic Personal Dosimeters (EPDs), which provide dose estimation in real time. This preference may lead to a generalized use of the EPD instead of using the required TLD, as the use of both types at once can be uncomfortable and impractical. In an effort to avoid this scenario, a gamma/neutron dosimeter composed of a TLD and an EPD is being developed. In this paper, the results obtained from the studies performed in order to develop the neutron albedo dosimeter to be incorporated in the TLD[Formula: see text]EPD dosimeter are presented. Monte Carlo simulations using the state-of-the-art Monte Carlo N-Particle Transport (MCNPX) code were used to calculate the response of the albedo dosimeter. The thermal neutron detectors under consideration for use in the proposed dosimeter are the EJ-426 and the EJ-420. Both detectors employ a lithium compoundenriched to 95% [Formula: see text]Li dispersed in a ZnS:(Ag) matrix. The tomographic phantom Korean Typical Man-2 was used in the simulations to calculate the fraction of radiation backscattered by a human body in different radiation field conditions. From these results, it was concluded that both dosimeters are fit to be used as albedo dosimeters.
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Guillou, M. Le, A. Billebaud, A. Gruel, G. Kessedjian, O. Méplan, C. Destouches y P. Blaise. "The CANDELLE experiment for characterization of neutron sensitivity of LiF TLDs". EPJ Web of Conferences 170 (2018): 04014. http://dx.doi.org/10.1051/epjconf/201817004014.
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As part of the design studies conducted at CEA for future power and research nuclear reactors, the validation of neutron and photon calculation schemes related to nuclear heating prediction are strongly dependent on the implementation of nuclear heating measurements. Such measurements are usually performed in low-power reactors, whose core dimensions are accurately known and where irradiation conditions (power, flux and temperature) are entirely controlled. Due to the very low operating power of such reactors (of the order of 100 W), nuclear heating is assessed by using dosimetry techniques such as thermoluminescent dosimeters (TLDs). However, although they are highly sensitive to gamma radiation, such dosimeters are also, to a lesser extent, sensitive to neutrons. The neutron dose depends strongly on the TLD composition, typically contributing to 10-30% of the total measured dose in a mixed neutron/gamma field. The experimental determination of the neutron correction appears therefore to be crucial to a better interpretation of doses measured in reactor with reduced uncertainties. A promising approach based on the use of two types of LiF TLDs respectively enriched with lithium-6 and lithium-7, precalibrated both in photon and neutron fields, has been recently developed at INFN (Milan, Italy) for medical purposes. The CANDELLE experiment is dedicated to the implementation of a pure neutron field “calibration” of TLDs by using the GENEPI-2 neutron source of LPSC (Grenoble, France). Those irradiation conditions allowed providing an early assessment of the neutron components of doses measured in EOLE reactor at CEA Cadarache with 10% uncertainty at 1σ.
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Kondo, Takeo, Toshihiro Kumabe, Shin Maruoka y Takashi Yoshimoto. "Diagnostic value of 201Tl—single-photon emission computerized tomography studies in cases of posterior fossa hemangioblastomas". Journal of Neurosurgery 95, n.º 2 (agosto de 2001): 292–97. http://dx.doi.org/10.3171/jns.2001.95.2.0292.
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Object. The 201Tl uptake index was evaluated for its usefulness in formulating a diagnosis of hemangioblastoma. Thallium-201—single-photon emission computerized tomography (SPECT) studies were performed in nine patients harboring hemangioblastomas in the posterior fossa and in five patients (six lesions) with gliomas in the posterior fossa. Methods. The 201Tl uptake index was defined as the ratio of mean counts of isotope per pixel in the tumor to mean counts of isotope per pixel in the homologous region of the healthy brain. The 201Tl uptake indices of the early image (TlE) and that of the delayed image (TlD) were calculated. The isotope retention index (RI) was calculated as (TlE − TlD)/TlE. The TlE was 2.7 ± 0.7 in hemangioblastomas and 2.9 ± 1.7 in gliomas (mean ± standard deviation). The TlD was 1.5 ± 0.4 in hemangioblastomas and 2.4 ± 1.6 in gliomas. There were no significant differences between hemangioblastomas and gliomas when TlEs and TlDs were compared. The isotope RI was 0.43 ± 0.07 in hemangioblastomas and 0.15 ± 0.1 in gliomas, showing a significantly higher RI in hemangioblastomas compared with gliomas (p < 0.01). Conclusions. Thallium-201 washout is significantly faster in hemangioblastomas. Hemangioblastoma is biologically benign, but contains a rich capillary network that forms a hypervascular tumor bed. Variations in its appearance on magnetic resonance images may cause difficulties in the differential diagnosis of hemangioblastoma. Thallium-201 SPECT studies can be used to distinguish hemangioblastomas from gliomas in the posterior fossa.
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Maimani, Abdulrauf, Abdulraheem Abdulrahman Kinsara, Badar Al Taayeb y Nurul Islam Molla. "Assessment of Breast Doses in Mammography Screening". Bangladesh Journal of Nuclear Medicine 18, n.º 2 (10 de enero de 2018): 161–67. http://dx.doi.org/10.3329/bjnm.v18i2.35238.
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Thermoluminescent dosimeters (TLD-100H) were in use for the assessment of average glandular dose to breast in mammography screening with GE machine, King Abdul Aziz University Hospital for 45 mm breast compressed thickness, 26 kVp, 100 mAs and Mo/Mo target/filter combination. Reader’s calibration factor for the TLDs was generated with the same exposure parameters using RadCal mammo ionization chamber as reference. The calibration factor was reproduced within 3% standard deviation. Several sets of selected TLD-100H placing in different configurations were exposed to X-ray beam under identical exposure condition as it was used for generation of calibration factor. The entrance surface doses were calculated by using the measured net TL-response and the calibration factor. Thereafter, the average glandular doses (AGD) were calculated. The measured average entrance surface dose (AGD) at the reference position (6 cm laterally centered from the chest edge wall) was 7.704 mGy with less than 2% standard deviation. The calculated average glandular dose to the breast at the reference location has been found to be 1.429 ± 0.037 mGy.Bangladesh J. Nuclear Med. 18(2): 161-167, July 2015
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Lee, J. H., L. T. Chang, A. C. Shiau, C. W. Chen, Y. J. Liao, W. J. Li, M. S. Lee y S. M. Hsu. "A Novel Simple Phantom for Verifying the Dose of Radiation Therapy". BioMed Research International 2015 (2015): 1–5. http://dx.doi.org/10.1155/2015/934387.
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A standard protocol of dosimetric measurements is used by the organizations responsible for verifying that the doses delivered in radiation-therapy institutions are within authorized limits. This study evaluated a self-designed simple auditing phantom for use in verifying the dose of radiation therapy; the phantom design, dose audit system, and clinical tests are described. Thermoluminescent dosimeters (TLDs) were used as postal dosimeters, and mailable phantoms were produced for use in postal audits. Correction factors are important for converting TLD readout values from phantoms into the absorbed dose in water. The phantom scatter correction factor was used to quantify the difference in the scattered dose between a solid water phantom and homemade phantoms; its value ranged from 1.084 to 1.031. The energy-dependence correction factor was used to compare the TLD readout of the unit dose irradiated by audit beam energies with60Co in the solid water phantom; its value was 0.99 to 1.01. The setup-condition factor was used to correct for differences in dose-output calibration conditions. Clinical tests of the device calibrating the dose output revealed that the dose deviation was within 3%. Therefore, our homemade phantoms and dosimetric system can be applied for accurately verifying the doses applied in radiation-therapy institutions.
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Bigdeli, Yasser y Dookie Kim. "Investigation of the Performance of Two Passive Controllers in Mitigating the Rotational Response of Irregular Buildings". Advances in Materials Science and Engineering 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/1898792.
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Two passive vibration control devices (i.e., circle type tuned liquid damper (C-TLD) and a circle type tuned liquid column damper (C-TLCD)) were experimentally investigated for their performance when attached to the irregular building structure subjected to dynamic loads. The specific directions where the maximum response of the structure is expected were experimentally identified for x- and y-directions as well as for rotational direction. The power spectral density (PSD) was computed for the response of the structure based on the frequency of the first three modes and also water level changes in the device container by using fast Fourier transform (FFT). The performances of these two controllers regarding suppressing the structural vibration were compared for the seismic loads applied in an experimentally identified critical direction. The results show that these systems are effective in terms of mitigating the coupled lateral and torsional vibrations of a scaled three-story irregular model.
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Pace, Martina, Giuseppe Stella, Letizia Barone Tonghi, Stefania Mazzaglia y Anna Maria Gueli. "CT-Dose Measurement of the Spinal Cord Region Using XR-QA2 Radiochromic Films and TLD 100H Dosimeters". Instruments 4, n.º 3 (3 de julio de 2020): 19. http://dx.doi.org/10.3390/instruments4030019.
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The European Directive 2013/59/Euratom focuses on the radiation protection and patient dosimetry. In particular, the dose absorbed by serial organs such as the spinal cord due to diagnostic exams plays a crucial role in the appraisal of medical exposure. In this work, a comparison between dose measurements performed with GafchromicTM XR-QA2 and TLD 100H is presented. The dosimeters—after a calibration procedure through an X-ray tube—were placed within the thorax region of an anthropomorphic phantom corresponding to the spinal cord area exposed to a thoracic CT procedure. The mean-dose value was measured with GafchromicTM first, and it was then compared to the dose value obtained with TLDs, resulting in a good agreement between the two dosimetric methodologies. Additionally, the results showed that—due to the usage of the automatic exposure control (EC) system—the discrepancy between the two methods is proportional to the current output of the CT system.
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Van Holsbeke, Cedric, Jan De Backer, Wim Vos y Jonathan Marshall. "Use of functional respiratory imaging to characterize the effect of inhalation profile and particle size on lung deposition of inhaled corticosteroid/long-acting β2-agonists delivered via a pressurized metered-dose inhaler". Therapeutic Advances in Respiratory Disease 12 (1 de enero de 2018): 175346661876094. http://dx.doi.org/10.1177/1753466618760948.
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Background: Functional respiratory imaging (FRI) uses three-dimensional models of human lungs and computational fluid dynamics to simulate functional changes within airways and predict the deposition of inhaled drugs. This study used FRI to model the effects of different patient inhalation and drug formulation factors on lung deposition of an inhaled corticosteroid/long-acting β2-agonist (ICS/LABA) combination, administered by a pressurized metered-dose inhaler. Methods: Three-dimensional models of the lungs of six patients with asthma (mean forced expiratory volume in 1 s, 83%), treated with an ICS/LABA, were included. FRI modelling was used to simulate (1) the effects on lung deposition of inhalation duration and particle size [fine particle fraction (FPF), proportion of particles <5 µm; and mass median aerodynamic diameter (MMAD), average size of inhalable particles]; (2) deposition of fluticasone propionate/formoterol (FP/FORM) 125/5 µg; and (3) how inhalation profiles and flow rates affected FP/FORM deposition. Results: Total lung depositions (TLDs) following 1-, 3- and 5-s inhalations were 22.8%, 36.1% and 41.6% (metered dose), respectively, and central-to-peripheral deposition (C:P) ratios were 1.81, 0.86 and 0.61, respectively. TLD increased with increasing FPF, from ~8% at 10% FPF to ~36% at 40% FPF (metered dose); by contrast, MMAD had little effect on TLD, which was similar across MMADs (1.5–4.5 µm) at each FPF. FP/FORM deposited throughout central and peripheral airways with gradual (sinusoidal) and sharp (rapid) inhalations. TLD ranged from 35.8 to 44.0% (metered dose) for gradual and sharp inhalations at 30 and 60 L/min mean flow rates. Conclusions: These data provide important insights into the potential effects of inhalation characteristics (inhalation profile and duration) and aerosol formulation (FPF) on lung deposition of inhaled therapies. FRI thus represents a useful alternative to scintigraphy techniques. Future FRI studies will further our understanding of the deposition of inhaled drugs and help improve the management of asthma.
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Ikari, Kazuki, Hideaki Masuda, Toshiyuki Oyamada y Tatsuo Sawada. "Frequency Analysis of Semi-Active Tuned Magnetic Fluid Column Damper with Two Electromagnets". Materials Science Forum 792 (agosto de 2014): 275–80. http://dx.doi.org/10.4028/www.scientific.net/msf.792.275.
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A new semi-active tuned liquid column damper (TLCD) that uses magnetic fluid as its working fluid (MF-TLCD) is presented. An MF-TLCD alters the natural frequency of the magnetic fluid column that forms the resident liquid inside the MF-TLCD by applying a magnetic field. We investigated the damping characteristics of an MF-TLCD equipped with two electromagnets, and also the transition of the natural frequency, which is strongly related to the damping performance. The coupled structure-MF-TLCD system was investigated both experimentally and by numerical analysis. The momentum equation of an MF-TLCD and its numerical solution are presented. The numerical results are validated by comparison with experimental results.
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Angelone, M., P. Batistoni, M. Chiti, A. Esposito y M. Pillon. "Study of TLD-300 as a Low Dose Detector and a Comparison with Standard High Sensitivity TLDs". Radiation Protection Dosimetry 85, n.º 1 (1 de septiembre de 1999): 245–48. http://dx.doi.org/10.1093/oxfordjournals.rpd.a032843.
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