Journal articles: 'Lag screw effect'

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TZENG, CHUNG-YUH, KUI-CHUO HUANG, YUN-CHE WU, CHU-LING CHANG, KUAN-RONG LEE, and KUO-CHIH SU. "BIOMECHANICAL EFFECT OF DIFFERENT LAG SCREW LENGTHS WITH DIFFERENT BARREL LENGTHS IN DYNAMIC HIP SCREW SYSTEM: A FINITE ELEMENT ANALYSIS STUDY." Journal of Mechanics in Medicine and Biology 17, no. 01 (February 2017): 1750008. http://dx.doi.org/10.1142/s0219519417500087.

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The dynamic hip screw (DHS) system is commonly used to treat intertrochanteric fracture of the hip joint. Breakage of the lag screw was noted in clinical practice and the length of lag screw as well as the length of the side plate in the DHS system appeared to play a role in the risk of breakage. Thus, the aim of this study was to investigate the biomechanical effect of different lag screw lengths and barrel plate lengths in the DHS implant system by finite element analysis (FEA). Four FEA simulation models were created according to different lengths of lag screw (79[Formula: see text]mm and 63[Formula: see text]mm) and different lengths of barrel side plate (43[Formula: see text]mm and 37[Formula: see text]mm). The von Mises stress was used as the observation indicator. The results showed that the maximum tensile stress on the long lag screw was slightly greater than that of the shorter lag screw. Use of a shorter barrel side plate may also cause high stress between the lag screw and the barrel side plate. This finding provides biomechanical reference data that may be of value to orthopedic surgeons with respect to choice of implant size and length in the treatment of intertrochanteric fracture with a DHS system to prevent complications such as implant failure caused by broken lag screws.

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Quinn, Robert, Anna Adrian, Martin Owen, Mark Bush, and Francisco Silveira. "Evaluation of the use of intra-operative radiology for open placement of lag screws for the stabilization of sacroiliac luxation in cats." Veterinary and Comparative Orthopaedics and Traumatology 30, no. 01 (2017): 69–74. http://dx.doi.org/10.3415/vcot-15-12-0201.

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SummaryObjectives: To assess the effect of intra- operative radiology on the quality of lag screw insertion for the management of sacroiliac joint luxations in cats.Methods: In this retrospective single-centre study, the surgical, anaesthetic and imaging records of 40 screws (32 cats) placed with lag effect for management of sacroiliac luxation were reviewed. Postoperative radio-graphs were assessed for sacroiliac joint reduction, screw position, and sacral width purchased by each screw. Cases were divided into two groups according to the use of (IOR) or the absence of intra-operative radiology (NIOR).Results: A total of 23 lag screws were placed with the aid of intra-operative radiology and 17 without. Three of the 23 screws placed in the IOR group exited the sacrum as opposed to eight of 17 screws in the NIOR group (p = 0.03). Mean sacral width purchased by the screws in the IOR group (70.8%) was also significantly higher (p = 0.002) than in the NIOR group (54.6%). Mean general anaesthetic times for unilateral and bilateral screw placement for the IOR group and NIOR group were not significantly different.Clinical significance: The use of intra-operative radiology can significantly improve the quality of lag screw insertion for the stabilization of sacroiliac luxations in cats, which should lead to a reduced incidence of postoperative screw loosening.

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Chang, Ya-Pei, Chi-Yuan Ho, Chao-Chang Chen, and Lih-Seng Yeh. "Biomechanical Comparison between Preloaded Position Screw and Lag Screw Fixations for Their Compressive Effects in a Porcine Rib Fracture Model." Veterinary and Comparative Orthopaedics and Traumatology 31, no. 03 (May 2018): 182–87. http://dx.doi.org/10.1055/s-0038-1639596.

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Objectives The aim of this study was to compare the compressive effect between preloaded position screws and lag screws in fracture fixation. Methods Pairs of semi-cylindrical bone fragments were created on a porcine rib model to simulate fractured bones. The compressive forces of fracture fixation generated by preloaded position screws (P group) and conventional lag screws (L group) were recorded by a film stress sensor. In the P group, a pair of Angus bone holding forceps was used to compress the interfragmentary interface until reaching the preloading force of 1.3 MPa. Similar preloading procedure was applied on lag screw fixations to explore its potential of additional compressive force. Results With 1.3 MPa preloading force and 0.2 Nm screw insertion torque force, the interfragmentary compressive force of P group was similar to that of L group. When the insertion torque force was increased to 0.4 Nm, all screws in the L group failed due to thread stripping. When screws in the P group were installed under 0.4 Nm torque and in the L group under 0.2 Nm torque, the P group generated significantly greater compressive force. With preloading device applied on lag screw installation, it did not further increase the interfragmentary compressive force. Clinical Significance Compared with lag screws, preloaded position screws tolerated greater torque in screw installation and provided greater interfragmentary compressive force. The study suggests the applicability of preloaded position screws in fracture fixation requiring interfragmentary compression.

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Chao, Ching-Kong, Chun-Ching Hsiao, and Po-Quang Chen. "Optimal Distal Screw Alignment in the Gamma Nail." Journal of Mechanics 18, no. 2 (June 2002): 103–8. http://dx.doi.org/10.1017/s1727719100002069.

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AbstractThe effect of stress distribution due to the changes of the distal screw alignment in relation to the Gamma nail and the femoral shaft is thoroughly studied in this paper. Failure of the Gamma nail composite occurs through the cranial aperture of the distal screws and the insertion hole for the lag screw due to nonunion, delayed-union and continued weight-bearing. A three-dimensional finite element model was used to study the fractured femur, the Gamma nail, the lag screw and the distal locking screws. The first and the second distal screws were inserted into the Gamma nail in four different configurations. We found that the stress of the Gamma nail composite was substantially reduced with the two screws configured in the anterior to posterior direction. This alignment can bear greater loading in the more demanding fracture types. In the subtrochanteric fracture or the comminuted fractures at the proximal femur, the optimal alignment of the two distal screws was in the anterior to posterior direction.

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WANG, CHENG-CHI, CHENG-HUNG LEE, KUN-HUI CHEN, CHIEN-CHOU PAN, and KUO-CHIH SU. "EFFECTS OF DIFFERENT LATERAL FEMORAL WALL THICKNESSES IN INTERTROCHANTERIC HIP FRACTURE TREATED WITH DYNAMIC HIP SCREW." Journal of Mechanics in Medicine and Biology 19, no. 02 (March 2019): 1940022. http://dx.doi.org/10.1142/s0219519419400220.

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Dynamic hip screw (DHS) is commonly used for stable-type intertrochanteric hip fractures. The importance of lateral femoral wall has been mentioned while treating intertrochanteric hip fractures with DHS. The aim of this study was mainly to investigate the biomechanical effect of different thickness of lateral femoral wall using finite element analysis (FEA). This study constructed FEA simulation models for five different lateral femoral wall thicknesses, and demonstrated the stress distribution on the femoral bone, the cortical screws, the cancellous bone around the lag screw, and the lag screw. The main results showed that when the DHS is implanted, less stress will be distributed at the implantation site on the femur due to the stress-shielding effect. The stress on the cortical screws will be greater at the junction of the cortical screws and the cortical bone. Intertrochanteric hip fractures with a thinner lateral wall thickness may cause higher stress on the femur after DHS is implanted.

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Wang, Cheng-Chi, Cheng-Hung Lee, Ning-Chien Chin, Kun-Hui Chen, Chien-Chou Pan, and Kuo-Chih Su. "Biomechanical analysis of the treatment of intertrochanteric hip fracture with different lengths of dynamic hip screw side plates." Technology and Health Care 28, no. 6 (November 17, 2020): 593–602. http://dx.doi.org/10.3233/thc-202248.

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BACKGROUND: Dynamic hip screw (DHS) is a common implant used to treat stable-type intertrochanteric hip fractures. There are many factors that can affect the success rate of the surgery, including the length of side plates. It is therefore important to investigate the biomechanical effect of different DHS side plates on bones. OBJECTIVE: In order to reduce the likelihood of an implant failure, the aim of this study was to use finite element analysis (FEA) to investigate and understand the effect of side plates with different lengths in DHS. METHODS: In this FEA study, a 3D model with cortical bone, cancellous bone, side plate, lag screw, and cortical screws to simulate the implantation of DHS with different lengths of side plate (2-hole, 4-hole, and 6-hole) for intertrochanteric hip fractures was constructed. The loading condition was used to simulate the force (400 N) on the femoral head and the stress distribution on the lag screw, side plate, cortical screws, and femur was measured. RESULTS: The highest stress points occured around the region of contact between the screw and the cortical bones. The stress on the femur at the most distal cortical screw was the greatest. The shorter the length of the side plate, the greater the stress on the cortical screws, resulting in an increased stress on the femur surrounding the cortical screws. CONCLUSIONS: The use of DHS with 2-hole side plate may increase the risk of side plate pull-out. The results of this study provide a biomechanical analysis for selection of DHS implant lengths that can be useful for orthopaedic surgeons.

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Sivakumar, Arjun, Dominic Thewlis, Andreas Ladurner, Suzanne Edwards, and Mark Rickman. "Proximal Femoral Nail Unlocked versus Locked (ProFNUL): a protocol for a multicentre, parallel-armed randomised controlled trial for the effect of femoral nail mode of lag screw locking and screw configuration in the treatment of intertrochanteric femur fractures." BMJ Open 10, no. 2 (February 2020): e032640. http://dx.doi.org/10.1136/bmjopen-2019-032640.

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IntroductionIntertrochanteric fractures are common fragility injuries in the elderly. Surgical fixation using intramedullary devices are one of the widely used management options. To date, evidence demonstrating the effects of lag screw configuration and the mode of lag screw locking in these devices is lacking. The purpose of this study is to investigate whether the lag screw configuration (single vs integrated dual interlocking screw) and the mode of lag screw locking (static vs dynamic) of a femoral nail device result in differences in clinical and functional outcomes.Methods and analysisA multicentre, pragmatic, single-blinded randomised controlled trial (RCT) with a three-arm parallel group design is proposed. Nine-hundred patients with intertrochanteric fractures (A1 and A2 AO/OTA) will be randomised to fracture treatment using a Gamma3 nail (Stryker; proximally dynamic) or a Trigen Intertan nail (Smith & Nephew) in a dynamic or static lag screw configuration. The primary outcome measure consists of radiological evidence of construct failure within 6 months following surgery, with failure being defined as breakage of the femoral nail or distal locking screw, a change in tip-apex distance of more than 10 mm or lag screw cut-out through the femoral head. Secondary outcomes include surgical data (operation time, fluoroscopy time), complications (surgical site infection, reoperation, patient death), return to mobility and home circumstances, functional independence, function and pain. Patients who are able to walk independently with or without a mobility aid and are able to answer simple questions and follow instructions will be asked to participate in three dimensional gait analysis at 6 weeks and 6 months to assess hip biomechanics from this cohort. Additional secondary measures of gait speed, hip range of motion, joint contact and muscle forces and gross activity monitoring patterns will be obtained in this subgroup.Ethics and disseminationThe Central Adelaide Local Health Network Human Research Ethics Committee has approved the protocol for this RCT (HREC/17/RAH/433). The results will be disseminated via peer-reviewed publications and presentations at relevant conferences.Trial registration numberACTRN12618001431213.

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Park, Jin, Jung Min Shin, Do Kyung Lee, Sung-Sahn Lee, Seung Ha Paik, and Byung Hoon Lee. "The Effect of Synthetic Osteoconductive Bone Graft Material for Augmentation of Internally Fixed Unstable Trochanteric Fractures." BioMed Research International 2019 (March 19, 2019): 1–8. http://dx.doi.org/10.1155/2019/5879089.

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This study aimed to evaluate whether the augmentation of CaP into the femoral head around the lag screw results in superior clinical and radiological outcomes of treatment of unstable trochanteric fractures using an intramedullary (IM) implant. Fifty-six consecutive patients with unstable trochanteric fractures who had been surgically treated with IM devices between 2014 and 2016 were prospectively reviewed and randomly divided into two groups based on the use of CaP degradable cements: 28 patients were assigned to the CaP group, while the other 28 patients were assigned to the control group (no use of CaP). Clinical evaluations and radiological analyses were conducted during a minimum of 2-year follow-up. No significant differences in the mean visual analogue scale for the hip pain scores and modified Harris Hip Scores were found between the CaP group and the controls at postoperative 2 months and 2 years. However, earlier walker ambulation was possible in the CaP group (10 ± 9 days) compared to the control group (13 ± 12 days) (P = 0.02). In radiological analysis, the CaP group showed significantly lower difference between tip-apex distance measured immediately after surgery and that measured at one-year follow-up compared to the control group (P = 0.012). No screw cut-out occurred in the CaP group, while one patient in the control group was reoperated for screw cut-out. The CaP augmentation into the femoral head around lag screw can reduce lag screw penetration, prevent screw cut-out beyond the femoral head, and facilitate early ambulation in elderly patients with unstable trochanteric fractures.

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Pallis, Mark P., David N. Pressman, Kenneth Heida, Tyler Nicholson, and Susan Ishikawa. "Effect of Ankle Position on Tibiotalar Motion With Screw Fixation of the Distal Tibiofibular Syndesmosis in a Fracture Model." Foot & Ankle International 39, no. 6 (March 30, 2018): 746–50. http://dx.doi.org/10.1177/1071100718759966.

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Background: Anatomic reduction and fixation of the syndesmosis in traumatic injuries is paramount in restoring function of the tibiotalar joint. While overcompression is a potential error, recent work has called into question whether ankle position during fixation really matters in this regard. Our study aimed to corroborate more recent findings using a fracture model that, to our knowledge, has not been previously tested. Methods: Twenty cadaver leg specimens were obtained and prepared. Each was tested for tibiotalar motion under various conditions: intact syndesmosis, intact syndesmosis with lag screw compression, pronation external rotation type 4 (PER-4) ankle fracture with syndesmotic disruption, and single-screw syndesmotic fixation followed by plate and screw fracture and syndesmotic screw fixation. In each situation, the ankle was held in alternating plantarflexion and dorsiflexion when inserting the syndesmotic screw with the subsequent amount of maximal dorsiflexion being recorded following hand-tight lag screw fixation. Results: While ankle range of motion increased significantly with creation of the PER-4 injury, under no condition was there a statistically significant change in maximal dorsiflexion angle. Conclusion: Ankle position during distal tibiofibular syndesmosis fixation did not limit dorsiflexion of the ankle joint. Clinical Relevance: Our findings suggest that maximal dorsiflexion during syndesmotic screw fixation may not be necessary.

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Huang, Tsan-Wen, Tien-Yu Yang, Kuo-Chin Huang, Kuo-Ti Peng, Mel S. Lee, and Robert Wen-Wei Hsu. "Effect of Teriparatide on Unstable Pertrochanteric Fractures." BioMed Research International 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/568390.

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We retrospectively analyzed the radiographic and clinical outcomes of unstable pertrochanteric fractures (AO/OTA 31-A2) in 44 patients who underwent dynamic hip screw (DHS) fixation and compared the results with 29 patients who received teriparatide in addition to DHS fixation. A significantly shorter time for fracture healing was recorded in the teriparatide-treated group than in the control group. Rates of lag screw sliding, femoral shortening, and varus collapse were all significantly reduced in the teriparatide-treated group. There were no significant differences with regard to superficial wound infection, pneumonia, urinary tract infection, mortality, malunion, and cutting of the lag screw. The mean overall mobility scores were significantly better in the teriparatide-treated group at 3 and 6 months (P<0.001andP<0.001, resp.) but not at 12 months or the last follow-up. The pain scores were also significantly better in the teriparatide-treated group at 3 and 6 months (P=0.040andP=0.041, resp.) but not at 12 months or the last follow-up. Teriparatide improves radiographic outcomes and yields better clinical outcomes at 3 and 6 months postoperatively. The improvement in union time may be important for elderly populations with unstable pertrochanteric fractures to enable them to return to daily activities and reduce morbidity and mortality.

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Ribeiro, Mariana Lopes, Cláudio Del Menezzi, Milton Luiz Siqueira, and Rafael Rodolfo de Melo. "EFFECT OF WOOD DENSITY AND SCREW LENGTH ON THE WITHDRAWAL RESISTANCE OF TROPICAL WOOD." Nativa 6, no. 4 (July 18, 2018): 402. http://dx.doi.org/10.31413/nativa.v6i4.5638.

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EFEITO DA DENSIDADE DA MADEIRA E DO COMPRIMENTO DO PARAFUSO NA RESISTÊNCIA AO ARRANCAMENTO EM MADEIRAS TROPICAIS Na maioria das ligações os pinos metálicos estão solicitados por forças laterais, mas ocasionalmente há a necessidade da utilização de parafusos auto-atarraxantes solicitados por esforços de tração. O objetivo deste trabalho foi determinar, de maneira experimental, a resistência ao arrancamento de parafuso auto-atarraxantes em espécies de madeiras tropicais, analisando-se a influência dos seguintes fatores: densidade da madeira e comprimento de penetração do parafuso. Para isso, foram feitos testes de arrancamento com parafusos sextavados de rosca soberba com 12,7 mmde diâmetro e diferentes comprimentos de rosca e corpos-de-prova confeccionados das seguintes espécies: angelim (Dinizia excelsa), freijó (Cordia goeldiana), ipê (Tabebuia sp.), louro-vermelho (Nectandra rubra), marupá (Simarouba amara). Verificou-se que a carga máxima de arrancamento de parafuso aumenta com o aumento do comprimento do parafuso inserido na madeira e da densidade da madeira. Contudo, a ruptura do parafuso em espécies mais densas pode ocorrer, pois a carga de arrancamento ultrapassa o limite de resistência do parafuso. Dessa forma, comprimentos de parafuso menores são recomendados para madeiras mais densas.Palavras-chave: ligações mecânicas, madeiras amazônicas, parafuso auto-atarraxante. ABSTRACT: In most timber connections a metallic pin is required due to lateral forces, but occasionally self-tapping screws are required due to tensile stresses. The aim of this study was to experimentally determine the withdrawal resistance of self-tapping screws in tropical wood species by analyzing the influence of wood density and screw penetration length. For this, withdrawal resistance tests using hex lag screws of 12.7 mmdiameter and different thread lengths were performed in specimens of the following species: Angelim (Dinizia excelsa), Freijó (Cordia goeldiana), Ipê (Tabebuia sp.), Louro-vermelho (Nectandra rubra), and Marupá (Simarouba amara). It was verified that the maximum load of screw withdrawal increases with increasing screw length inserted in wood and wood density. However, screw rupture may occur in denser species because the withdrawal load exceeds the screw strength limit. Therefore, lower screw lengths are recommended for denser woods.Keywords: mechanical connections, amazon timber, self-tapping screw.

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Sturgeon, C., A. M. Wilson, P. McGuigan, T. J. Lawes, and P. Muir. "Triceps Tenotomy and Double Plate Stabilization of “Y-T” Fracture of the Humeral Condyle in Three Dogs." Veterinary and Comparative Orthopaedics and Traumatology 13, no. 01 (2000): 34–38. http://dx.doi.org/10.1055/s-0038-1632627.

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SummaryCaudal elbow arthrotomy by use of triceps tenotomy was performed for open reduction of “Y-T” fractures of the humeral condyle in three dogs. Stabilization of the fracture was achieved by use of a bone screw inserted with a lag effect to compress the articular fracture and placement of bone plates on the caudolateral surface of the lateral epicondylar crest and the caudomedial surface of the medial epicondylar crest. This construct successfully maintained reduction in all three dogs without implant loosening or breakage. All three of the fractures healed satisfactorily without any evidence of progressive osteoarthritis. Long-term (median - 20 months) function of the affected limb was comparable to the contralateral limb, with little loss of elbow range-of-motion and minimal to an absence of lameness.Triceps tenotomy was used for open reduction of “Y-T” fractures of the humeral condyle in three dogs. Stabilization of the fracture with a bone screw inserted for lag effect and use of a bone plate on each epicondylar crest resulted in satisfactory healing of the fracture and good limb function in all of the patients.

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Wusqo, Urwatul, Ali Awaludin, Angga Fajar Setiawan, and Inggar Septhia Irawati. "Study of Laminated Veneer Lumber (LVL) Sengon to Concrete Joint Using Two-Dimensional Numerical Simulation." Journal of the Civil Engineering Forum 5, no. 3 (September 18, 2019): 275. http://dx.doi.org/10.22146/jcef.47694.

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The connection system is a critical part of Timber – Concrete Composite (TCC) floor structures. The behaviour of the connection needs to be known to predict the behaviour of composite structure accurately. Screws are one kind of connector that mostly used in the composite structure due to its installation ease and high withdrawal strength. This study carried out a two-dimensional numerical simulation to examine the behaviour of LVL Sengon-concrete joint using OpenSees software. The lag screw used to connect LVL Sengon and concrete. In this simulation, the screw was assumed as a beam with hinges element that supported by a set of springs representing the strength of LVL Sengon and concrete. Some input parameters for this simulation were obtained from the material test and previous research. The effect of secondary axial force was considered into the load-displacement curve resulted from the numerical simulation. This study performed several simulations towards the variation of the screw diameter, penetration depth, and concrete compressive strength. The capacity of the connections resulted from the numerical simulation were overestimates the manual calculation using EYM theory and NDS 2018 equations. The capacity of the connection increased about 146% to 284% due to the addition of secondary axial forces. In addition, this simulation can adequately predict the shear force, bending moment, and deformation of the screw. There is a plastic hinge formed in the screw after the screw being deformed a quite large. It shows the same yield mode with the manual calculation using EYM theory and NDS 2018 equations. This simulation also can show the contribution of each spring elements to resist the load until its ultimate strength.

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Aguillera, Maísa de Oliveira, Gustavo Silva Pelissaro, José Carlos Garcia de Mendonça, Janayna Gomes Paiva Oliveira, Alana Oswaldina Gavioli Meira dos Santos, and Ellen Cristina Gaetti Jardim. "Fixação cirúrgica de fratura oblíqua de mandíbula utilizando lag screw: relato de caso." ARCHIVES OF HEALTH INVESTIGATION 9, no. 6 (December 29, 2020): 670–73. http://dx.doi.org/10.21270/archi.v9i6.4985.

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A mandíbula se configura como um dos ossos mais acometidos por trauma no esqueleto maxilofacial em virtude de sua projeção anteriorizada. Sua localização está associada a direção e força do impacto, ocorrendo mais frequentemente na região de ângulo mandibular seguidas de sínfise e corpo. O tratamento de qualquer tipo de fratura consiste na redução e fixação dos fragmentos ósseos, o mais precoce possível, assim que as condições gerais do paciente permita. Este trabalho tem como objetivo descrever uma das técnicas de fixação interna rígida mandibular, utilizando parafusos na técnica lag screw. Relato de caso: Paciente, 37 anos, gênero feminino, compareceu ao pronto atendimento do Hospital Maria Aparecida Pedrossian com histórico de agressão física cursando com dificuldades de mastigação, apresentando ao exame tomográfico fratura de corpo mandibular com moderado deslocamento e em posição oblíqua. Diante do exame clinico e tomográfico, optou-se como conduta terapêutica o tratamento cirúrgico sob anestesia geral por meio da técnica lag screw que se mostrou uma técnica com resultado satisfatório até o momento e menos oneroso para o sistema publico de saúde. Descritores: Mandíbula; Fixação de Fratura; Cirurgia Bucal. Referências Flandes MP, Dias LBGM, Paulesini Junior W. Fratura de mandíbula – relato de caso. Rev Odontol Univ Cid São Paulo. 2019; 31(2):205-12. Zamboni RA, Wagner JCB, Volkweis MR, Gerhardt EL, Buchmann EM, Bavaresco CS. Levantamento epidemiológico das fraturas de face do Serviço de Cirurgia e Traumatologia Bucomaxilofacial da Santa Casa de Misericórdia de Porto Alegre – RS. Rev Col Bras Cir. 2017; 44(5):491-97. Dantas BPSS, Fialho PV, Fernandes ACF, Silva DT, Queiroz CS. Fratura complexa de mandíbula: relato de caso. Rev Odontol Araçatuba. 2017; 38(3):43-8. Hupp JR, Ellis III E, Tucker MR. Cirurgia Oral e Maxilofacial. 5.ed. Rio de Janeiro: Elsevier; 2009. Wang R, Liu Y, Wang JH, Baur DA. Effect of interfragmentary gap on the mechanical behavior of mandibular angle fracture with three fixation designs: A finite element analysis. J Plast Reconstr Aesthet Surg. 2017;70(3):360-69. Brons R, Boering G. Fractures of the mandibular body treated by stable internal fixation: a preliminary report. J Oral Surg. 1970;28(6):407-15. Campolongo GD, Barros TP, Amantéa DV. Fixação das fraturas mandibulares, utilizando a técnica lag screw associada à sedação: relado de caso. Rev Cir Traumatol Buco-Maxilo-Fac. 2005, 5(1):39-44. Fonseca RJ, Walker RV, Barber HD, Powers MP, Frost DE. Trauma Bucomaxilofacial. 4.ed. Rio de Janeiro: Elsevier; 2015. Miloro M, Ghali GE, Larsen PE, Waite PD. Princípios de cirurgia bucomaxilofacial de Peterson. 3.ed. São Paulo: Santos; 2016. El-Anwar MW, Sweed AH, Abdulmonaem G. Mental Foramen Relation to Mandibular Fracture. J Craniofac Surg. 2016;27(8):e743-e745. Mendonça JCG, Gaetti Jardim EG, Manrique GR, Freitas GP. Acesso cirúrgico para tratamento de fraturas mandibulares: Revisão de literatura. Arch Heath Invest. 2013;2(2):19-23. Ramalho RA, Araújo FAC, Santos FSM, Caubi AF, Sobreira T. Tratamento de fratura de mandibula: miniplacas e parafusos x lag screws - relato de caso. Rev Cir Traumatol Buco-Maxilo-Fac. 2011;11(1):9-12. Pereira ICS, Galdino AS, Palitó APPG, Santos TL, Barros F, Sobreira T. Redução cirúrgica de fratura mandibular oblíqua: parafusos transcorticais x placas de titânio - relatos de caso. Rev Cir Traumatol Buco-Maxilo-Fac. 2011;11(3):69-76.

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Yoo, Je-Hyun, Tae-Young Kim, Jun-Dong Chang, Yoon-Hae Kwak, and Yong-Shin Kwon. "Factors Influencing Functional Outcomes in United Intertrochanteric Hip Fractures: A Negative Effect of Lag Screw Sliding." Orthopedics 37, no. 12 (December 1, 2014): e1101-e1107. http://dx.doi.org/10.3928/01477447-20141124-58.

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Ramachandran, Karthik, K. K. Arvind Manoj, and A. Vishnu Sankar. "Critical analysis of factors determining mechanical failures in proximal femoral nailing." International Journal of Research in Orthopaedics 5, no. 2 (February 23, 2019): 275. http://dx.doi.org/10.18203/issn.2455-4510.intjresorthop20190504.

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Background: Intertrochanteric fractures are one of the commonest fractures encountered in elderly population. Though there are various implants, proximal femoral nail has been the standard choice for management of unstable fractures. Inspite of its biomechanical advantages, various complications like screw cut out, Z effect, reverse Z effect does occur in proximal femoral nailing. The aim of the study is to analyse various factors determining the mechanical failures in patients operated with proximal femoral nail.Methods: This is a prospective study conducted in our institution from June 2014 to May 2018. The study included 72 patients with unstable intertrochanteric fractures treated with proximal femoral nail. All patients were followed for average period of 2 years. Functional outcome was assessed using Harris Hip score.Results: Among the patients 33% had excellent outcome. 42% had good and 14% had fair outcome. 11% of cases ended with poor outcome. Mechanical failure rate was less in patients with positive medial cortical support (PMCS) and in patients with tip apex distance difference between antirotation screw and lag screw (TADAR -TADLS) more than 15 mm. Whereas the difference in the position of lag screw centre had no significant influence in the mechanical failure rate in our study.Conclusions: From our study we like to conclude that the fracture reduction with positive medial cortical support and the TAD difference play a major role in determining the incidence of mechanical failure in proximal femoral nailing.

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Fialkov, Jeffrey A., John H. Phillips, and Sharon L. Walmsley. "The Effect of Infection and Lag Screw Fixation on the Union of Membranous Bone Grafts in a Rabbit Model." Plastic and Reconstructive Surgery 93, no. 3 (March 1994): 574–81. http://dx.doi.org/10.1097/00006534-199493030-00021.

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Fialkov, Jeffrey A., John H. Phillips, and Sharon L. Walmsley. "The Effect of Infection and Lag Screw Fixation on the Union of Membranous Bone Grafts in a Rabbit Model." Plastic and Reconstructive Surgery 93, no. 3 (March 1994): 574–81. http://dx.doi.org/10.1097/00006534-199403000-00021.

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Wu, Chi-Chuan, and Ching-Lung Tai. "Effect of Lag-Screw Positions on Modes of Fixation Failure in Elderly Patients with Unstable Intertrochanteric Fractures of the Femur." Journal of Orthopaedic Surgery 18, no. 2 (August 2010): 158–65. http://dx.doi.org/10.1177/230949901001800206.

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Lal, Hitesh, Deepak Kumar Sharma, and Deepak Mittal. "Intrapelvic migration of hip lag screw of proximal femoral nail-sequele to a paradoxical reverse Z effect and their critical analysis." Journal of Clinical Orthopaedics and Trauma 3, no. 1 (June 2012): 48–53. http://dx.doi.org/10.1016/j.jcot.2012.02.002.

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Rugg, Amanda L., Melissa R. Requist, Brooks W. Johnson, Michelle M. Son, Alicia Alvarez, and L. Daniel Latt. "Mechanical Effects of Lag Screw Retightening in a Simulated Hindfoot Arthrodesis Model." Foot & Ankle Orthopaedics 6, no. 2 (January 1, 2021): 247301142110152. http://dx.doi.org/10.1177/24730114211015203.

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Background: Nonunion following hindfoot arthrodesis may be caused by failure to maintain compression at the arthrodesis site. The ability of lag screws, commonly used in arthrodesis, to maintain compression in hindfoot bones has not been well characterized. The aim of this work was to quantify the stress relaxation response of hindfoot bone with initial and repeated compression with a lag screw. Methods: Ten sets of 25-mm-diameter bone cylinders were cut from the talus and calcaneus in fresh-thawed cadaveric feet. A load cell was compressed between cylinders with an 8.0-mm partially threaded cannulated lag screw simulating arthrodesis. For 7 sets, screws were tightened by 3 quarter-turns, rested for 3 minutes, retightened 1 quarter-turn, and rested for 30 minutes. Three sets served as controls in which screws were not retightened. Results: Maximum compression after initial screw tightening and retightening averaged 275 and 337 N ( P = .07), respectively. Compression 3 minutes after initial screw tightening and retightening averaged 199 and 278 N ( P = .027), respectively. The compression recorded 3 minutes after screw retightening was an average of 40% higher than that recorded 3 minutes after initial tightening. The average compression 30 minutes after screw retightening was 255 N, a compression loss of 25% from the average maximum compression after retightening. Eighty percent of this compression loss happened in an average of 5.5 minutes. Conclusion: Hindfoot bones exhibit compression loss over time during simulated arthrodesis. Compression maintenance in bone is improved with screw retightening. Further work is needed to understand the mechanism of action and determine optimum time for recompression. Clinical Relevance: Retightening lag screws before wound closure may improve compression at the arthrodesis site and thereby decrease the chance of nonunion. Level of Evidence: N/A, laboratory experiment.

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Fialkov, Jeffrey A., John H. Phillips, Sharon L. Walmsley, and I. Morava-Protzner. "The Effect of Infection and Lag Screw Fixation on Revascularization and New Bone Deposition in Membranous Bone Grafts in a Rabbit Model." Plastic and Reconstructive Surgery 98, no. 2 (August 1996): 338–45. http://dx.doi.org/10.1097/00006534-199608000-00021.

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Berkowitz, Mark J., Sara-Lyn Miniaci, Alan Davis, Deepak Ramanathan, Khalid Hasan, Greg Strnad, Jeffrey Coombs, Yuxuan Jin, Kurt P. Spindler, and Stephen J. Pinney. "A Prospective Assessment of Great Toe Fusion Outcomes: The Effect of Concomitant Procedures." Foot & Ankle Orthopaedics 5, no. 4 (October 1, 2020): 2473011420S0012. http://dx.doi.org/10.1177/2473011420s00126.

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Category: Midfoot/Forefoot; Bunion Introduction/Purpose: Great toe fusion is the standard of care for severe hallux rigidus and other great toe pathology requiring definitive surgical management. Great toe fusion has proven an effective surgical treatment when correctly performed on appropriate patients. This study aimed to prospectively assess the clinical results of great toe fusion surgery in isolation compared to great toe fusion surgery combined with concomitant procedures. Methods: All patients undergoing a 1st metatarsophalangeal joint fusion from January 1st 2017 through June 30th 2018 were prospectively studied. Patients completed the Foot and Ankle Outcome Score (FAOS) and Veterans RAND 12 (VR-12) patient- reported outcome measures (PROMs) on the day of surgery (T0) and 12 months post-surgery (T1). Surgeons were surveyed regarding surgical details and patient characteristics. 204 patients underwent a great toe fusion during the study period. There were 67 enrollment failures (2 patient refusals, 63 incomplete T0 patient surveys, 2 incomplete surgeon surveys). Of the 137 patients completing the initial PROMs at T0, 100 patients (73%) also completed the PROMs at T1. Within this study group, 54 patients underwent an isolated great toe fusion and 46 underwent one or more concomitant procedures including hammertoe correction (30); MTP joint capsulotomy (22); Weil osteotomy (19); bunionette (2); metatarsal head resection (3); and other (12). Results: The study group consisted of 80 females and 20 males with age = 63.3 +/-8.5 and BMI = 28.3 +/-6.0. Indications for surgery included: hallux rigidus (26%), hallux valgus (35%), hallux varus (7%), arthritic bunions (30%) and other (2%). Fixation constructs included: a plate and a lag screw (82%), a plate alone (15%), and lag screws alone (3%). Patients undergoing isolated great toe fusions and those undergoing concomitant procedures both improved at one year (Table 1). Multivariable analysis demonstrated that after controlling for confounding variables, patients undergoing an isolated great toe fusion when compared to those also undergoing a concomitant procedure had higher odds for improvement in: FAOS pain (odds Ratio = 0.34, p=0.011); FAOS QoL (Odds Ratio=0.38, p=0.022); and VR-12 PCS (Odds Ratio=0.58, p=0.162). Conclusion: A great toe fusion can lead to substantial improvement in pain, quality of life, and overall physical function. However, this study demonstrates that the addition of a concomitant procedure such as a claw toe correction or a Weil osteotomy leads to an inferior outcome with respect to pain and quality of life when compared to an isolated great toe fusion. [Table: see text]

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Takemoto, Richelle C., Nikola Lekic, Ran Schwarzkopf, Frederick J. Kummer, and Kenneth A. Egol. "The effect of two different trochanteric nail lag-screw designs on fixation stability of four-part intertrochanteric fractures: a clinical and biomechanical study." Journal of Orthopaedic Science 19, no. 1 (January 2014): 112–19. http://dx.doi.org/10.1007/s00776-013-0493-z.

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Hong, Wan, Yuchen Jiang, Yong Fang, and Xiamin Hu. "Experimental study and theoretical analysis of glulam-concrete composite beams connected with ductile shear connectors." Advances in Structural Engineering 23, no. 6 (December 4, 2019): 1168–78. http://dx.doi.org/10.1177/1369433219891560.

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Ductile shear connectors are often applied in timber-concrete composite beams. The relative interface slip of such kind of composite beams will affect the mechanical performance of the composite beams and result in structural nonlinearity. Gamma method which adopts effective bending stiffness to reflect semi-rigid connection is recommended in Eurocode 5. The effective bending stiffness is irrelevant to external loads and calculation points of the composite beam. However, actual bending stiffness distribution along the beam is variable due to that shear connectors are subjected to different shear force. In order to verify the accuracy of gamma method, four-point bending tests of a total of three glulam-concrete composite beams with lag screw connectors and one pure glulam beam were conducted in this article. The failure mode, bearing capacity, and load–deflection relationship were investigated in the experiment. Meanwhile, push-out tests of composite beams were also conducted for determination of the force–displacement relationship of ductile shear connectors. Then, numerical simulation using beam-truss model was established for investigation on the mechanism of composite beams. Finally, theoretical analysis of composite beams considering the effect of interface slip was also presented. Comparing results from gamma method with the presented method, it is shown that both methods can calculate deflection at serviceability limit state with high precision. However, non-uniform distribution of actual bending stiffness cannot be reflected by gamma method.

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Rompen, Ingmar F., Matthias Knobe, Bjoern-Christian Link, Frank J. P. Beeres, Ralf Baumgaertner, Nadine Diwersi, Filippo Migliorini, Sven Nebelung, Reto Babst, and Bryan J. M. van de Wall. "Cement augmentation for trochanteric femur fractures: A meta-analysis of randomized clinical trials and observational studies." PLOS ONE 16, no. 6 (June 15, 2021): e0251894. http://dx.doi.org/10.1371/journal.pone.0251894.

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Introduction To date, it is unclear what the clinical benefit of cement augmentation in fixation for trochanteric fractures is. The aim of this meta-analysis is to compare cement augmentation to no augmentation in fixation of trochanteric femur fractures in the elderly patients (>65 years) following low energy trauma. Methods PubMed/Medline/Embase/CENTRAL/CINAHL were searched for both randomized clinical trials (RCT) and observational studies comparing both treatments. Effect estimates were pooled across studies using random effects models. Subgroup analysis was performed stratified by study design (RCTs and observational studies). The primary outcome is overall complication rate. Secondary outcomes include re-operation rate, mortality, operation duration, hospital stay, general quality of life, radiologic measures and functional hip scores. Results A total of four RCT’s (437 patients) and three observational studies (293 patients) were included. The effect estimates of RCTs were equal to those obtained from observational studies. Cement augmentation has a significantly lower overall complication rate (28.3% versus 47.2%) with an odds ratio (OR) of 0.3 (95%CI 0.1–0.7). The occurrence of device/fracture related complications was the largest contributing factor to this higher overall complication rate in the non-augmented group (19.9% versus 6.0%, OR 0.2, 95%CI 0.1–0.6). Cement augmentation also carries a lower risk for re-interventions (OR 0.2, 95%CI 0.1–0.7) and shortens the hospital stay with 2 days (95%CI -2.2 to -0.5 days). The mean operation time was 7 minutes longer in the augmented group (95%CI 1.3–12.9). Radiological scores (lag screw/blade sliding mean difference -3.1mm, 95%CI -4.6 to -1.7, varus deviation mean difference -6.15°, 95%CI; -7.4 to -4.9) and functional scores (standardized mean difference 0.31, 95%CI 0.0–0.6) were in favor of cement augmentation. Mortality was equal in both groups (OR 0.7, 95%CI 0.4–1.3) and cement related complications were rare. Conclusion Cement augmentation in fixation of trochanteric femoral fractures leads to fewer complications, re-operations and shorter hospital stay at the expense of a slightly longer operation duration. Cementation related complications occur rarely and mortality is equal between treatment groups. Based on these results, cement augmentation should be considered for trochanteric fractures in elderly patients.

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Godzik, Jakub, George M. Mastorakos, Gautam Nayar, William D. Hunter, and Luis M. Tumialán. "Surgeon and staff radiation exposure in minimally invasive spinal surgery: prospective series using a personal dosimeter." Journal of Neurosurgery: Spine 32, no. 6 (June 2020): 817–23. http://dx.doi.org/10.3171/2019.11.spine19448.

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OBJECTIVEThe level of radiation awareness by surgeons and residents in spinal surgery does not match the ubiquity of fluoroscopy in operating rooms in the United States. The present method of monitoring radiation exposure may contribute to the current deficiency in radiation awareness. Current dosimeters involve a considerable lag from the time that the surgical team is exposed to radiation to the time that they are provided with that exposure data. The objective of the current study was to assess the feasibility of monitoring radiation exposure in operating room personnel during lateral transpsoas lumbar interbody fusion (LLIF) and minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) procedures by using a wearable personal device with real-time feedback.METHODSOperating room staff participating in minimally invasive surgical procedures under a single surgeon during a 6-month period were prospectively enrolled in this study. All radiation dose exposures were recorded for each member of the surgical team (surgeon, assistant surgeon, scrub nurse, and circulating nurse) using a personal dosimeter (DoseAware). Radiation doses were recorded in microsieverts (μSv). Comparisons between groups were made using ANOVA with the Tukey post hoc test and Student t-test.RESULTSThirty-nine patients underwent interbody fusions: 25 underwent LLIF procedures (14 LLIF alone, 11 LLIF with percutaneous screw placement [PSP]) and 14 underwent MI-TLIF. For each operative scenario per spinal level, the surgeon experienced significantly higher (p < 0.035) average radiation exposure (LLIF: 167.9 μSv, LLIF+PSP: 424.2 μSv, MI-TLIF: 397.9 μSv) than other members of the team, followed by the assistant surgeon (LLIF: 149.7 μSv, LLIF+PSP: 242.3 μSv, MI-TLIF: 274.9 μSv). The scrub nurse (LLIF: 15.4 μSv, LLIF+PSP: 125.7 μSv, MI-TLIF: 183.0 μSv) and circulating nurse (LLIF: 1.2 μSv, LLIF+PSP: 9.2 μSv, MI-TLIF: 102.3 μSv) experienced significantly lower exposures. Radiation exposure was not correlated with the patient’s body mass index (p ≥ 0.233); however, it was positively correlated with increasing patient age (p ≤ 0.004).CONCLUSIONSReal-time monitoring of radiation exposure is currently feasible and shortens the time between exposure and the availability of information regarding that exposure. A shortened feedback loop that offers more reliable and immediate data would conceivably raise the level of concern for radiation exposure in spinal surgeries and could alter patterns of behavior, leading to decreased exposures. Further studies are ongoing to determine the effect of real-time dosimetry in spinal surgery.

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He, Hong, and Jian Guo Zhou. "On-Line Measurement of Rheological Properties of LDPE, HDPE and LDPE/MICA Systems in Single-Screw Extrusion." Advanced Materials Research 941-944 (June 2014): 1788–91. http://dx.doi.org/10.4028/www.scientific.net/amr.941-944.1788.

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The quality of extrudate is closely related to its rheological properties during extrusion. Therefore, on-line measurement of rheological properties of polymer is important in extrusion process. In the present work, comparisons between the on-line viscosities of LDPE in single screw extruder and that in lab under the same condition were made by using online rheometer. Effects of set temperature of on-line rheometer, screw configuration and different positions, as well as weight proportions of filler, size of MICA particles of LDPE/MICA multiphase system on the melt viscosity in single screw extrusion are discussed.

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Kraemer, W., T. Hearn, M. Tile, and J. Powell. "The effect of thread length and location on extraction strengths of iliosacral lag screws." Injury 25, no. 1 (January 1994): 5–9. http://dx.doi.org/10.1016/0020-1383(94)90176-7.

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Egger, E., J. Huhta, M. Histand, C. Mallinckrodt, and R. Nye. "Acute Failure Characteristics of Six Methods for Internal Fixation of Canine Femoral Oblique Fractures." Veterinary and Comparative Orthopaedics and Traumatology 09, no. 03 (July 1996): 106–10. http://dx.doi.org/10.1055/s-0038-1632513.

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SummaryA long oblique osteotomy model of canine femoral fractures was created to compare six methods of internal fixation. The following methods were tested: three cerclage wires, three lag screws, eight-hole dynamic compression plate attached with six cerclage wires, eight-hole dynamic compression plate attached with six cortical screws, eight-hole dynamic compression plate attached with six cortical screws superimposed over three cerclage wires, and an eight-hole dynamic compression plate attached with six cortical screws superimposed over three lag screws. The repaired femurs were mounted in a mechanical testing machine in an orientation designed to mimic physiological loading. Axial compression was applied which resulted in the test specimens experiencing simultaneous compressive and bending forces. The effects of the method of osteotomy repair, bone temperature, and bone diameter were analyzed. The maximum load and the stiffness of the composite fixation and bones were determined. There were not any statistically significant differences in stiffness among the groups. All fixation methods, in which plates were attached with screws, resulted in significantly greater maximum load values than treatment techniques where plates were not used. None of the fixation methods attained a mean maximum load greater than 58% of the mean maximum load of the control femurs.Six methods of commonly used internal fixation methods are compared. A method of in vitro positioning of test femurs to mimic in vivo orientation is presented. Maximum load capabilities of fixation do not significantly increase with the addition of interfragmentary compression to plate fixation.

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Matsubara, Doppo, Yoshiaki Wakashima, Yasushi Fujisawa, Hidemaru Shimizu, Akihisa Kitamori, and Koichiro Ishikawa. "Effects of tightening speed on torque coefficient in lag screw timber joints with steel side plates." Journal of Wood Science 64, no. 2 (December 12, 2017): 112–18. http://dx.doi.org/10.1007/s10086-017-1679-3.

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Johnson, Jeremiah N., and Michael Y. Wang. "Stress fracture of the lumbar pedicle bilaterally: surgical repair using a percutaneous minimally invasive technique." Journal of Neurosurgery: Spine 11, no. 6 (December 2009): 724–28. http://dx.doi.org/10.3171/2009.7.spine08373.

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Bilateral pedicle fractures in the spine are uncommon in the absence of bony abnormality, previous surgery, or trauma. The authors report a case of spontaneous bilateral lumbar pedicle fracture in a 50-year-old sedentary woman, which caused intractable pain and did not respond to months of conservative management. The fractures were surgically treated using a percutaneous, minimally invasive technique with screws placed directly through the fractures into the vertebral body. The pedicles were strategically tapped to achieve the lag effect and reapproximate the posterior fragment with the anterior elements. The patient tolerated the procedure well and experienced early improvement of her symptoms, and follow-up imaging showed evidence of fracture healing. Transpedicular fixation and the use of the lag effect could be a useful strategy in the treatment of future cases involving poorly healing pedicle fractures causing persistent symptoms.

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Karunanithy, Chinnadurai, and Kasiviswanathan Muthukumarappan. "Optimization of alkali, big bluestem particle size, and extruder parameters for maxium enzymatic sugar recovery using response surface methodology." BioResources 6, no. 1 (January 18, 2011): 762–90. http://dx.doi.org/10.15376/biores.6.1.762-790.

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Extrusion can be a viable continuous biomass pretreatment that industry can adopt readily due to its uniqueness (including pretreatment time less than 90 s) over other pretreatment methods. The current study was undertaken to evaluate the combined effect of alkali soaking and extrusion of big bluestem to improve the sugar recovery to nearly quantitative. In order to evaluate the combined effect of alkali soaking and extrusion on the performance of enzymatic saccharification, big bluestem (2-10 mm) was soaked in different alkali concentrations (0.5-2.5 % w/v NaOH) for 30 min at room temperature and then extruded using a lab scale single screw extruder at various barrel temperatures (45-225°C) and screw speeds (20-200 rpm). Statistical analyses confirmed that all the independent variables considered had a significant effect on sugar recovery. A proposed quadratic model to predict sugar recovery had high F and R2 values with a low p value, and adequately represented the relationship among the independent variables on sugar recovery. The optimum pretreatment condition found was the following: 90°C barrel temperature, 155 rpm screw speed, 2.0% alkali concentration, and 4 mm particle size resulted the maximum glucose, xylose, and combined sugar recovery of 90.1, 91.5, and 89.9%, respectively.

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Takemoto, Richelle C., Michelle T. Sugi, Frederick Kummer, Kenneth J. Koval, and Kenneth A. Egol. "The Effects of Locked and Unlocked Neutralization Plates on Load Bearing of Fractures Fixed With a Lag Screw." Journal of Orthopaedic Trauma 26, no. 9 (September 2012): 519–22. http://dx.doi.org/10.1097/bot.0b013e31823b3dd1.

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Cordey, J. R., D. M. Nunamaker, M. L. Tate, T. McIff, S. M. Perren, and A. S. Turner. "In Vitro Strain Patterns of the Intact Equine Metacarpus and Metatarsus Following Plate Luting." Veterinary and Comparative Orthopaedics and Traumatology 3, no. 03 (1990): 84–89. http://dx.doi.org/10.1055/s-0038-1633234.

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SummaryWith internal fixation of fractures using a plate and screws, the stability of the fixation is achieved mainly by the force generated by either lag screws or plate screws. The plate protects the bone from overload. The important mechanism in the function of plate fixation is the friction between the undersurface of the plate and the bone surface. It has become evident that plate luting, i. e. interposition of a bone cement layer between the plate and the bone, will alter the transmission of expected forces due to improved contact between the plate and the bone. The purpose of this project was to evaluate the load/strain relationships that occurred following plate luting and to understand why this procedure improved the mechanical behaviour of plate fixation in equine bone. We measured the strain patterns that occurred in unplated, plated and luted equine third metacarpal and metatarsal bones under simulated physiological conditions. Plate application resulted in reduced strain under the plate and increased strain at the opposite cortex. Following plate luting, this effect was more pronounced. Hysteresis between the loading-unloading cycle was less pronounced in the luted plates. This indicated that plate luting increased the effect of strain protection.Plate luting was shown to reduce the strain under the plate and to increase it in the transcortex, effectively increasing the effect of strain protection.

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Fang, Jifeng, Hui Dong, and Zihui Li. "Comparison of Curative Effects between Minimally Invasive Percutaneous Lag Screw Internal Fixation and Reconstruction Plate for Unstable Pelvic Fractures." Journal of the College of Physicians and Surgeons Pakistan 30, no. 01 (January 1, 2020): 28–32. http://dx.doi.org/10.29271/jcpsp.2020.01.28.

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Wilczyński, Kamil, Zbigniew Kobus, and Dariusz Dziki. "Effect of Press Construction on Yield and Quality of Apple Juice." Sustainability 11, no. 13 (July 2, 2019): 3630. http://dx.doi.org/10.3390/su11133630.

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The paper presents the possibility of applying different press constructions for juice extraction in small farms. The research was carried out with three different varieties of apples, namely, Rubin, Mutsu, and Jonaprince. Two types of presses were tested: a basket press and a screw press. Generally, application of the screw press makes it possible to obtain a higher yield of extraction compared to the basket press. In our study, the differences in the pressing yield among press machines also depended on the apple variety used. The juices obtained on the screw press were found to be of a higher quality characterized by a higher content of soluble solids, higher viscosity, higher total content of polyphenols, higher antioxidant activity, and lower acidity. Thus, the selection of an appropriate press is the key to producing high-quality apple juice with health-promoting properties for manufacturers of apple juice at the local marketplace.

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Rus, Anika Zafiah Mohd, and Nurulsaidatulsyida Sulong. "Fundamental Technique of Pre-Blending of Bio-Matrix with Commercial HDPE." Applied Mechanics and Materials 393 (September 2013): 121–25. http://dx.doi.org/10.4028/www.scientific.net/amm.393.121.

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The effect of bio-polymer as bio-matrix material with HDPE for the blending process is described in this study. 10%, 20%, 30%, 40% and 50% of bio-polymer was added to the HDPE and then blended by using Brabender Plastograph machine using mixer and roller screw and the test specimens were prepared by injection moulding. The compatibility of the origin bio-polymer (VOP), HDPE and the bio-matrix of bio-polymer/ HDPE (BioPE) were observed during the injection moulding process. Dumbbell shape of tensile test specimens were produced according to ISO 527-2 (5A) from the injection moulding process. Mixing process was successfully conducted based on two different matrix which is lab scale bio-polymer and production of commercial thermoplastic materials.

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Durmus, Ali, Mehmet Ozcan, and Ismail Aydin. "Quantifying effects of compositional variations on microstructural properties of polypropylene-wood fiber composites by melt rheology and tensile test data." Journal of Composite Materials 53, no. 4 (July 10, 2018): 503–14. http://dx.doi.org/10.1177/0021998318786792.

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In this study, melt-state rheological behavior and solid-state mechanical properties of polypropylene-wood fiber composites were investigated in detail depending on compositional variations such as (i) alkaline treatment on wood fibers, (ii) fiber size, (iii) wood fiber content, and (iv) compatibilizer/wood fiber ratio. Composite samples were prepared in a lab-scale co-rotating twin screw extruder by using a maleic anhydride grafted polypropylene as compatibilizer. Morphological features of composites were examined in a scanning electron microscopy. Viscoelastic behavior and mechanical properties of samples were analyzed by performing oscillatory tests in a rotational rheometer and a universal tensile test machine. It was found that the increasing amounts of wood fiber and compatibilizer/wood fiber ratio led to improve melt elasticity and tensile strength. It was concluded that the amount of compatibilizer into composite formulation was the most important compositional parameter compared to size and chemical treatment of wood fibers for improving the physical properties of composites. The Nicolais-Nicodemo micromechanical model showed that the increasing amount of compatibilizer yielded lower parameters which implied better interfacial adhesion between polypropylene and wood fibers.

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Hoang, Thi Thu Linh, Thi Gam Do, Van Thao Nguyen, Hoai Chau Nguyen, and Hong Khoi Phan. "Environmental Impacts of Photoluminescence and Light-Emitting Diode (LED) Lighting Technologies in Horticulture: Case Study on Compact Fluorescent Lamp (CFL) and LED Lights for “Night Break” of Chrysanthemum Cultivation." Sustainability 12, no. 19 (September 25, 2020): 7969. http://dx.doi.org/10.3390/su12197969.

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The environmental impacts of photoluminescence and light-emitting diode (LED) lighting technologies in horticulture are described in this paper. As a case study, the life cycle assessment (LCA) associated with the raw materials, air, water and natural resources of screw-based compact fluorescent lamps (CFLs) and screw-based horticultural LED lamps (abbreviated as H-LED) used for “night break” effect in chrysanthemum cultivation is considered. Instead of the unit of radiant power of lighting sources (lumens) used in human lighting, the photon flux (micromoles per second) of the plant light is used in this study. The results of the study show that the environmental impacts of the H-LED lighting technology are markedly less than the fluorescent lamps. Therefore, the shift to LED lighting technology in horticulture in general, and “night break” chrysanthemum cultivation in particular, brings about tremendous benefits not only for saving energy and improving crop quality, but also for protecting the air/climate, water, soil and natural resources.

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Kim, Jin-Doo, Tai-Ju Lee, Jae-Hoon Lee, Jeong-Yong Ryu, and Jong-Myoung Won. "Circular action treatment (CAT): a new strategy for mechanical treatment of old corrugated container III." Nordic Pulp & Paper Research Journal 34, no. 3 (September 25, 2019): 362–70. http://dx.doi.org/10.1515/npprj-2018-0070.

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Abstract OCC have been the most important raw material for production of papers for industrial grades. The quality of OCC fibers have been deteriorated by repeated recycling process. In order to overcome the defects of OCC CAT has been developed as a new strategy for old corrugated container (OCC), which could generate mild mechanical action. The effect of CAT was proven through the previous researches which showed the increase of the fiber properties, such as WRV, freeness, and strength properties, and positive effect on paper strength. Based on the results, mill-scale application of CAT was performed at a linerboard mill located in Republic of KOREA. In this paper, mill-scale CAT was designed with higher power and dimension compared to the previous lab-scale CAT, which was equipped at the screw press outlet in a papermaking process. Fiber properties, final product quality, and energy consumption were analyzed with the installation of mill-scale CAT. Freeness and WRV were improved with an increase of passing time, and mean fiber length was constant simultaneously. In terms of process runnability, there was no problem during the test. Furthermore the outstanding achievement was found that the energy could be saved using CAT by around 30 % compared to double-disc low-consistency refining. Consequently CAT could be a new alternative for treatment of OCC without any troubles.

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Aranburu, Nora, Itziar Otaegi, and Gonzalo Guerrica-Echevarria. "Using an Ionic Liquid to Reduce the Electrical Percolation Threshold in Biobased Thermoplastic Polyurethane/Graphene Nanocomposites." Polymers 11, no. 3 (March 6, 2019): 435. http://dx.doi.org/10.3390/polym11030435.

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Biobased thermoplastic polyurethane (bTPU)/unmodified graphene (GR) nanocomposites (NCs) were obtained by melt-mixing in a lab-scaled conventional twin-screw extruder. Alternatively, GR was also modified with an ionic liquid (GR-IL) using a simple preparation method with the aim of improving the dispersion level. XRD diffractograms indicated a minor presence of well-ordered structures in both bTPU/GR and bTPU/GR-IL NCs, which also showed, as observed by TEM, nonuniform dispersion. Electrical conductivity measurements pointed to an improved dispersion level when GR was modified with the IL, because the bTPU/GR-IL NCs showed a significantly lower electrical percolation threshold (1.99 wt%) than the bTPU/GR NCs (3.21 wt%), as well as higher conductivity values. Young’s modulus increased upon the addition of the GR (by 65% with 4 wt%), as did the yield strength, while the ductile nature of the bTPU matrix maintained in all the compositions, with elongation at break values above 200%. This positive effect on the mechanical properties caused by the addition of GR maintained or slightly increased when GR-IL was used, pointing to the success of this method of modifying the nanofiller to obtain bTPU/GR NCs.

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Molinari, Giovanna, Vito Gigante, Stefano Fiori, Laura Aliotta, and Andrea Lazzeri. "Dispersion of Micro Fibrillated Cellulose (MFC) in Poly(lactic acid) (PLA) from Lab-Scale to Semi-Industrial Processing Using Biobased Plasticizers as Dispersing Aids." Chemistry 3, no. 3 (August 25, 2021): 896–915. http://dx.doi.org/10.3390/chemistry3030066.

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In the present study, two commercial typologies of microfibrillated cellulose (MFC) (Exilva and Celish) with 2% wt % were firstly melt-compounded at the laboratory scale into polylactic acid (PLA) by a microcompounder. To reach an MFC proper dispersion and avoid the well-known aglomeration problems, the use of two kinds of biobased plasticisers (poly(ethylene glycol) (PEG) and lactic acid oligomer (OLA)) were investigated. The plasticizers had the dual effect of dispersing the MFC, and at the same time, they counterbalanced the excessive stiffness caused by the addition of MFC to the PLA matrix. Several preliminaries dilution tests, with different aqueous cellulose suspension/plasticizer weight ratios were carried out. These tests were accompanied by SEM observations and IR and mechanical tests on compression-molded films in order to select the best plasticizer content. The best formulation was then scaled up in a semi-industrial twin-screw extruder, feeding the solution by a peristaltic pump, to optimize the industrial-scale production of commercial MFC-based composites with a solvent-free method. From this study, it can be seen that the use of plasticisers as dispersing aids is a biobased and green solution that can be easily used in conventional extrusion techniques.

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Ferraioli, Raffaella, Loredana Incarnato, Luciano Di Maio, and Paola Scarfato. "A Preliminary Study on Recyclability of Mixed Plastic Wastes Recovered from Urban Collection." Key Engineering Materials 885 (May 2021): 109–14. http://dx.doi.org/10.4028/www.scientific.net/kem.885.109.

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The management of post-consumer plastic waste (PCPW) is a real challenging issue due to difficulties in effectively identifying and sorting the collected plastics and in their mechanical recycling. Indeed, mechanically recycled post-consumer plastic waste usually shows poor performances compared to virgin materials, due to incompatibility between constituents, presence of degraded materials, hygroscopicity and bad odors. Compatibilizers and nanoparticles can help to improve recycled plastics quality, but to be chosen and dosed properly they require an in-depth knowledge and characterization of the raw waste. In this study, an analysis of polymeric materials obtained from the separation and mechanical recycling of post-consumer plastic wastes from urban collection as pellets (UPW) is reported. In particular, the experimental characterization was carried out in order to identify UPW composition, water content, physical-chemical properties and processability. It was found that UPW samples are mainly constituted of polyethylene (PE) and polypropylene (PP) in equal parts. UPW was submitted to a melt processing operation, using a lab-scale single-screw extruder, obtaining ribbons that were completely characterized. With the aim to investigate the effect of water content on the recycled material processability and performance, the recycling process was carried out both on undried and dried UPW pellets.

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Chou, Pang-Yun, Ying-Chao Chou, Yu-Hsuan Lai, Yu-Ting Lin, Chia-Jung Lu, and Shih-Jung Liu. "Fabrication of Drug-Eluting Nano-Hydroxylapatite Filled Polycaprolactone Nanocomposites Using Solution-Extrusion 3D Printing Technique." Polymers 13, no. 3 (January 20, 2021): 318. http://dx.doi.org/10.3390/polym13030318.

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Polycaprolactone/nano-hydroxylapatite (PCL/nHA) nanocomposites have found use in tissue engineering and drug delivery owing to their good biocompatibility with these types of applications in addition to their mechanical characteristics. Three-dimensional (3D) printing of PCL/nHA nanocomposites persists as a defiance mostly because of the lack of commercial filaments for the conventional fused deposition modeling (FDM) method. In addition, as the composites are prepared using FDM for the purpose of delivering pharmaceuticals, thermal energy can destroy the embedded drugs and biomolecules. In this report, we investigated 3D printing of PCL/nHA using a lab-developed solution-extrusion printer, which consists of an extrusion feeder, a syringe with a dispensing nozzle, a collection table, and a command port. The effects of distinct printing variables on the mechanical properties of nanocomposites were investigated. Drug-eluting nanocomposite screws were also prepared using solution-extrusion 3D printing. The empirical outcomes suggest that the tensile properties of the 3D-printed PCL/nHA nanocomposites increased with the PCL/nHA-to-dichloromethane (DCM) ratio, fill density, and print orientation but decreased with an increase in the moving speed of the dispensing tip. Furthermore, printed drug-eluting PCL/nHA screws eluted high levels of antimicrobial vancomycin and ceftazidime over a 14-day period. Solution-extrusion 3D printing demonstrated excellent capabilities for fabricating drug-loaded implants for various medical applications.

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Fiss, Ingo, Dorothee Mielke, Veit Rohde, Marios Psychogios, and Christoph Schilling. "Correlation between different instrumentation variants and the degree of destabilization in treating cervical spondylotic spinal canal stenosis by unilateral hemilaminectomy with bilateral decompression: a biomechanical investigation." European Spine Journal 30, no. 6 (March 10, 2021): 1529–35. http://dx.doi.org/10.1007/s00586-021-06773-9.

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Abstract Purpose Unilateral hemilaminectomy with bilateral decompression (BDZ) was proposed as an alternative decompressive procedure in cervical spondylotic myelopathy (CSM). Despite promising clinical results, the destabilizing effect is yet unknown. We therefore performed a biomechanical study to investigate whether lateral mass screw fixation should follow BDZ. Methods Six human C2–C7 cervical specimens were tested under various conditions: native, unilateral hemilaminectomy with bilateral decompression without/with fixation (BDZ/BDF), unilateral hemilaminectomy with bilateral decompression and unilateral foraminotomy without/with fixation (UFZ/UFF), unilateral hemilaminectomy with bilateral decompression and bilateral foraminotomy without/with fixation (BFZ/BFF), and laminectomy without/with fixation (LAZ/LAF). Instrumention was applied from C3–C6. For each condition, the three-dimensional kinematics of the cervical specimen were measured in three main loading directions with an ultrasonic motion analysis system. ANOVA was used to determine differences between the specific segment conditions to assess the parameter’s range of motion (ROM) and neutral zone (NZ). Results For flexion–extension, lateral bending and axial rotation, ROM of BDZ, UFZ, BFZ and LAZ remained at the level of the native condition (p > 0.74), whereas fixation reduced ROM significantly (p < 0.01). Between BDF, UFF, BFF and LAF, no significant differences in reduction in ROM were seen (p > 0.49). Results for NZ were equivalent to ROM in flexion–extension and lateral bending. For axial rotation, NZ remained almost constant on the native level for all tested conditions. Conclusion Bilateral decompression via a hemilaminectomy, even if combined with foraminotomy, could be a less invasive treatment option for multilevel CSM in patients with lordotic cervical alignment and absence of segmental instability.

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Nicolosi, Salvatore Fabio. "Refashioning the EU Visa Policy: A New Turn of the Screw to Cooperation on Readmission and to Discrimination?" European Journal of Migration and Law 22, no. 4 (December 11, 2020): 467–91. http://dx.doi.org/10.1163/15718166-12340089.

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Abstract Since the establishment of the Schengen area, border management has been having momentum within the European Union (EU) and, one of its major building blocks is the common policy on visas. This allows to control who can have access to the Schengen area for short stays that do not exceed three months over any six-month period. This article investigates how the EU visa policy has been influenced by the ever-evolving migratory dynamics towards the EU. Focusing on the latest reform of the Common Code on Visa, which has entered into force in 2020, this article argues that the new approach to conditionality in EU migration law has consolidated the intertwining between the EU visa policy and cooperation on readmission. Over the years, the latter has constituted an incentive for the EU in order to offer visa facilitation regimes or specific visa waivers to nationals of third countries. However, this article criticizes the new mechanism, introduced by the recent reform, and providing the European Commission with the mandate to propose specific restrictive measures related to visa processing and visa fee in case of a lack of cooperation especially on readmission. In an attempt to shed light on the legal concerns raised by this mechanism, the paper concludes that it even emphasises the discriminatory effects of the EU visa policy and, more generally, it impacts on the cooperation with third countries within the EU General Approach to Migration and Mobility.

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Kazmer, David O., Davide Masato, Leonardo Piccolo, Kyle Puleo, Joshua Krantz, Varun Venoor, Austin Colon, et al. "Multivariate Modeling of Mechanical Properties for Hot Runner Molded Bioplastics and a Recycled Polypropylene Blend." Sustainability 13, no. 14 (July 20, 2021): 8102. http://dx.doi.org/10.3390/su13148102.

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Four sustainable materials including a recycled polypropylene blend, polybutylene adipate terephthalate, and two grades of polylactic acid are compared to a reference isotactic polypropylene. Tensile specimens were produced using a two-cavity, hot runner mold with fully automatic cycles per standard industrial practices to investigate the effect of melt temperature, injection velocity, cycle time, and screw speed on the mechanical properties. Multiple regression and principal component analyses were performed for each of the materials. Results indicated that all the materials were readily processed using a hot runner, and the mechanical properties exhibited minimal variation. To the extent that losses in mechanical properties were observed, the results indicated that the losses were correlated with thermal degradation as independently characterized by thermal gravimetric analysis. Such losses can be minimized by reducing melt temperature and cycle time, leading to a reduction of the environmental impact of injection molding processes.

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Thedinga, John F., Michael L. Murphy, Scott W. Johnson, J. Michael Lorenz, and K. V. Koski. "Determination of Salmonid Smolt Yield with Rotary-Screw Traps in the Situk River, Alaska, to Predict Effects of Glacial Flooding." North American Journal of Fisheries Management 14, no. 4 (November 1994): 837–51. http://dx.doi.org/10.1577/1548-8675(1994)014<0837:dossyw>2.3.co;2.

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Byrka, Katarzyna, Katarzyna Cantarero, Dariusz Dolinski, and Wijnand Van Tilburg. "Consequences of Sisyphean Efforts: Meaningless Effort Decreases Motivation to Engage in Subsequent Conservation Behaviors through Disappointment." Sustainability 13, no. 10 (May 19, 2021): 5716. http://dx.doi.org/10.3390/su13105716.

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This paper explores the consequences of engaging in conservation efforts that later appear purposeless. Specifically, we tested the model in which disappointment lays at the root of decreased motivation in such situations. In Studies 1 and 2, participants (n = 239 and n = 283) imagined that they had recycled plastic bottles for a week and that an assistant had collected their garbage in either separate bags (meaningful condition) or only one bag (meaningless condition). Half of participants imagined that they had put plastic bags and screw caps into separate containers (low-effort condition), the other half imagined that they had torn off the label bands (high-effort condition). In Study 3, a longitudinal field experiment, participants (n = 286) took part in a real situation that followed the procedure from Studies 1 and 2. Altogether, we confirmed the moderating effect of effort on relationship between meaninglessness and motivation through experienced disappointment. We discuss consequences of efforts wasted for beliefs, intentions and behaviors affording sustainable solutions.

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Journal articles on the topic 'Lag screw effect'

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