scholarly journals Biomechanical evaluation of temporary epiphysiodesis at the femoral epiphysis using established devices from clinical practice

2021 ◽  
Vol 32 (4) ◽  
Author(s):  
Charlotte Struwe ◽  
Sebastian G. Walter ◽  
Claudia Druschel ◽  
Rahel Bornemann ◽  
Milena Ploeger ◽  
...  
Keyword(s):  
Primary Outcome ◽  
Testing Machine ◽  
Individual Preference ◽  
Maximum Load ◽  
Hydraulic Testing ◽  
Lateral Group ◽  
Fresh Frozen ◽  
Biomechanical Evaluation ◽  
Biomechanical Features ◽  
The Individual

AbstractThe aim of this study is to compare biomechanical features of different devices used in clinical routine for temporary epiphysiodesis (eight-Plate® and FlexTackTM). The tested implants were divided into four different groups (eight-Plate® vs. FlexTackTM for lateral and anterior implantation) á 10 samples for testing implanted eight-Plate® vs. FlexTackTM in fresh frozen pig femora for maximum load forces (Fmax) and axial physis distance until implant failure (lmax). A servo hydraulic testing machine (858 Mini Bionix 2) was used to exert and measure reproducible forces. Statistical analyses tested for normal distribution and significant (p < 0.05) differences in primary outcome parameters. There were no significant differences between the eight-Plate® lateral group and the FlexTackTM lateral group for neither Fmax (p = 0.46) nor lmax (p = 0.65). There was a significant higher Fmax (p < 0.001) and lmax (p = 0.001) measured in the eight-Plate® group compared to the FlexTackTM group when implanted anteriorly. In anterior temporary ephiphysiodesis, eight-Plate® demonstrated superior biomechanical stability. At this stage of research, there is no clear advantage of either implant and the choice remains within the individual preference of the surgeon.

scholarly journals Biomechanical Evaluation of Tarsometatarsal Fusion Comparing Crossing Lag Screws and Lag Screw With Locking Plate

2021 ◽  
pp. 107110072110335
Author(s):  
Sarah Ettinger ◽  
Lisa-Christin Hemmersbach ◽  
Michael Schwarze ◽  
Christina Stukenborg-Colsman ◽  
Daiwei Yao ◽  
...  
Keyword(s):  
Locking Plate ◽  
Screw Fixation ◽  
Operative Procedure ◽  
Fixation Technique ◽  
Lag Screw ◽  
Group 15 ◽  
Fresh Frozen ◽  
Biomechanical Evaluation ◽  
The Stability ◽  
End Stage

Background: Tarsometatarsal (TMT) arthrodesis is a common operative procedure for end-stage arthritis of the TMT joints. To date, there is no consensus on the best fixation technique for TMT arthrodesis and which joints should be included. Methods: Thirty fresh-frozen feet were divided into one group (15 feet) in which TMT joints I-III were fused with a lag screw and locking plate and a second group (15 feet) in which TMT joints I-III were fused with 2 crossing lag screws. The arthrodesis was performed stepwise with evaluation of mobility between the metatarsal and cuneiform bones after every application or removal of a lag screw or locking plate. Results: Isolated lag-screw arthrodesis of the TMT I-III joints led to significantly increased stability in every joint ( P < .05). Additional application of a locking plate caused further stability in every TMT joint ( P < .05). An additional crossed lag screw did not significantly increase rigidity of the TMT II and III joints ( P > .05). An IM screw did not influence the stability of the fused TMT joints. For TMT III arthrodesis, lag-screw and locking plate constructs were superior to crossed lag-screw fixation ( P < .05). TMT I fusion does not support stability after TMT II and III arthrodesis. Conclusion: Each fixation technique provided sufficient stabilization of the TMT joints. Use of a lag screw plus locking plate might be superior to crossed screw fixation. An additional TMT I and/or III arthrodesis did not increase stability of an isolated TMT II arthrodesis. Clinical Relevance: We report the first biomechanical evaluation of TMT I-III arthrodesis. Our results may help surgeons to choose among osteosynthesis techniques and which joints to include in performing arthrodesis of TMT I-III joints.

Strength of side-to-side and step-cut repairs in tendon transfers: biomechanical testing of porcine flexor tendons

2020 ◽  
Vol 45 (10) ◽  
pp. 1061-1065
Author(s):  
Eivind Strandenes ◽  
Peter Ellison ◽  
Anders O. Mølster ◽  
Nils R. Gjerdet ◽  
Irene O. Moldestad ◽  
...  
Keyword(s):  
Tensile Properties ◽  
Testing Machine ◽  
Biomechanical Testing ◽  
Maximum Load ◽  
Side Group ◽  
Tendon Transfers ◽  
Flexor Tendons ◽  
Active Mobilization ◽  
The Difference

The aim of the study was to compare side-to-side with step-cut repairs to determine how much of the width it is possible to remove and still keep the repair strong enough to start active mobilization. Porcine flexor tendons were used to create side-to-side, one-third step-cut and half step-cut repairs. There were 15 repairs in each group. The tensile properties of the constructs were measured in a biomechanical testing machine. All repairs failed by the sutures splitting the tendon longitudinally. The maximum load and stiffness were highest in the side-to-side group. Our findings suggest that the half step-cut repair can withstand the forces exerted during active unrestricted movement of the digits in tendons of this size. The advantage of the step-cut repair is reduced bulkiness and less friction, which might compensate for the difference in strength.

Anti-craving biofeedback program in clinical course of pathological addictions

2017 ◽  
Vol 41 (S1) ◽  
pp. s879-s879
Author(s):  
I. Sosin ◽  
Y. Chuev ◽  
A. Volkov ◽  
O. Goncharova
Keyword(s):  
Individual Preference ◽  
Emotional States ◽  
Digital Information ◽  
External Monitoring ◽  
Computer Testing ◽  
Mode Of Life ◽  
Competing Interest ◽  
The Individual ◽  
Monitoring Module ◽  
And Control

IntroductionModern clinical narcology searches for anti-craving programs to overcome psychoactive substances (PAS) pathological addiction with bio-adaptive regulation of systems (BARS).Aims and objectivesTo develop computer modified biofeedback program integrated with Luscher test.MethodTwenty-two PAS addicts who were undergoing biofeedback modified psycho-training were examined. Computer rheoencephalogram (REG) was used as an external monitoring module.ResultsTechnologically novel biofeedback computer modification was developed with preceding Luscher computer testing for determination of the individual preference colour and the colour producing individual unpleasant associations in respondents. Consequently, biofeedback program was corrected differentially by changing standard colour templates for those personified on monitor. Cerebral hemodynamics condition transferred to individually designed for a particular respondent colour registers is used as a homeostatic parameter reflecting alcohol craving presence/absence: in case of the disordered REG parameters the signal reflects the respondent's unpleasant (negative) colour, and with no craving the screen is filled with positive, pleasant, favourite colour. During BARS auto-training the respondents’ skills to mediate present subjective clinical PAS craving manifestations with unpleasant colour and the experimental auto-training method have been mastered, and those psycho emotional states which displace PAS craving symbolic colour from the screen are selected, and it is substituted with favourite colour (symbol of healthy mode of life motivations).ConclusionsUsage of combined BARS biofeedback improved effectiveness of the training and allowed to objectivize and control the condition of the patient getting reliable visual and digital information about either regress or activation of PAS craving and potential relapse of addictive behaviour.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Using Embossing to Create a Fiber Reinforced Honeycomb Composite

2005 ◽  
Vol 127 (2) ◽  
pp. 257-262 ◽  
Author(s):  
William Jordan
Keyword(s):  
Tensile Strength ◽  
Composite Material ◽  
Carbon Fibers ◽  
Flexural Modulus ◽  
Testing Machine ◽  
Charpy Impact ◽  
Tensile Tests ◽  
Hydraulic Testing ◽  
Charpy Impact Toughness ◽  
Bend Tests

This research project used hot embossing to create a strong and tough polymeric based composite structure. A honeycomb type structure was created by pressing small grooves into thin polycarbonate sheets. A trapezoidal die was used to create hexagonal shaped channels in the polymeric sheet. A number of these sheets were then bonded together to form a composite material. Carbon fibers were embedded into the channels in some of the laminates. The embossing process was carried out at an elevated temperature in an environmental chamber attached to an MTS servo hydraulic testing machine. The grooved structure had a 31% to 45% decrease in the apparent density compared to the ungrooved specimens. Bend tests, tensile tests, and Charpy impact tests were performed on laminates made from this material. The specific values of tensile strength, flexural modulus, and Charpy impact toughness were increased. A small percentage of fibers significantly increased both the stiffness and strength of the laminate.

Dynamic Behaviour of Reinforcing Steel Bars in Tension

2011 ◽  
Vol 82 ◽  
pp. 86-91 ◽  
Author(s):  
Ezio Cadoni ◽  
Matteo Dotta ◽  
Daniele Forni ◽  
Nicoletta Tesio
Keyword(s):  
Testing Machine ◽  
Maximum Load ◽  
Gauge Length ◽  
Strain Rates ◽  
Reinforcing Bars ◽  
Static Tests ◽  
Split Hopkinson Tensile Bar ◽  
Steel Bars ◽  
Split Hopkinson ◽  
Reinforced Steel

In this paper the preliminary results of the tensile behavior of reinforced steel in a large range of strain rates are presented. Tensile testing at several strain rates, using different experimental set-ups, was carried out. For the quasi-static tests a universal electromechanical testing machine with the maximum load-bearing capacity of 50 kN was used, while for the intermediate and high-strain rate regimes a hydro-pneumatic apparatus and a JRC-Split Hopkinson Tensile Bar respectively were used. The target strain rates were set at the following five levels: 10-3, 30, 250, 500, and 1000 1/s. The specimens used in this research were round samples having 3mm in diameter and 5mm of gauge length obtained from reinforcing bars. Finally, the material parameters for Cowper-Symonds and Johnson-Cook models were determined.

Examination of the Effectiveness of Direct Oral Anticoagulants in Comparison to Warfarin in an Obese Population

2021 ◽  
pp. 875512252110641
Author(s):  
Rachel M. Watson ◽  
Carmen B. Smith ◽  
Erica F. Crannage ◽  
Laura M. Challen
Keyword(s):  
Primary Outcome ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Efficacy And Safety ◽  
Class Iii ◽  
Vein Thrombosis ◽  
Class Iii Obesity ◽  
Recurrent Vte ◽  
The Individual ◽  
Deep Vein

Background: While commonly prescribed today, direct oral anticoagulants (DOACs) have historically been avoided in patients with class III obesity or a weight >120 kg due to limited literature regarding the efficacy and safety in this population. Objective: The overall objective was to examine the effectiveness of DOACs compared to warfarin in a population with obesity. Methods: Patients with a diagnosis of venous thromboembolism (VTE) or atrial fibrillation and a body mass index (BMI) ≥35 kg/m2 from August 1, 2015, to August 1, 2020, were included in this retrospective cohort study. Patients receiving a DOAC were matched in a 1:2 ratio to warfarin. The primary outcome was a composite of stroke or recurrent VTE. Secondary outcomes included the individual components of the primary outcome, hospitalization for bleed, and the primary outcome in patients with a BMI ≥40 kg/m2. Results: A total of 162 patients were included, with 54 and 108 in the DOAC and warfarin groups, respectively. Baseline BMI was similar between groups (45.7 kg/m2 for DOACs vs 43.8 kg/m2 for warfarin), with approximately 70% of patients having a BMI ≥40 kg/m2. The primary outcome occurred in 1 patient (1.9%) in the DOAC group and 2 patients (1.9%) in the warfarin group. The DOAC group had a higher, nonsignificant incidence of bleeding (5.6% vs 0.9%, P = 0.11). There was no difference between groups in incidence of deep vein thrombosis (DVT), pulmonary embolism (PE), or stroke in patients with a BMI ≥40 kg/m2. Conclusion: DOACs may be as efficacious as warfarin in the prevention of stroke or recurrent VTE in patients with a BMI of ≥35 kg/m2. Prospective, randomized trials are warranted to further assess the efficacy and safety of DOACs in this population.

scholarly journals Neuromuscular and biomechanical functions subserving finger dexterity in musicians

2019 ◽  
Author(s):  
Yudai Kimoto ◽  
Takanori Oku ◽  
Shinichi Furuya
Keyword(s):  
Individual Differences ◽  
Movement Control ◽  
Neuromuscular Control ◽  
Penalized Regression ◽  
Movement Speed ◽  
Finger Dexterity ◽  
Motor Dexterity ◽  
Biomechanical Features ◽  
The Individual ◽  
Motor Actions

ABSTRACTExceptional finger dexterity enables skillful motor actions such as those required for musical performance. However, it has been not known whether specialized neuromuscular or biomechanical features subserve the dexterity. We aimed to identify the features firstly differentiating the finger dexterity between trained and untrained individuals and secondly accounting for the individual differences in the dexterity across trained individuals. To this aim, two studies were conducted. The first study (Study 1) compared the finger motor dexterity and several neuromuscular and biomechanical characteristics of the fingers between pianists and musically untrained individuals (non-musicians). The results showed no differences in any biomechanical features between the groups with different musical expertise. However, the pianists exhibited faster individual finger movements and more independent control of movements between the fingers. These observations indicate expertise-dependence of the finger motor skills and neuromuscular control of the fingers. The second study (Study 2) assessed individual differences in the finger dexterity between trained pianists. A penalized regression determined an association of the maximum movement speed of the pianists’ individual fingers with both finger muscular strength and biomechanical characteristics of the hand, but not with independent movement control between the fingers. In addition, none of these features covaried with measures of early and deliberate piano practice. Taken together, these findings indicate that distinct biological factors of finger motor dexterity differentiate between the effects of piano training and individual differences across skilled pianists.

scholarly journals 24-hour Fire Produced Effect on Reinforced Recycled Aggregates Concrete Beams

2019 ◽  
Vol 9 (3) ◽  
pp. 4213-4217 ◽  
Author(s):  
A. H. Buller ◽  
M. Oad ◽  
B. A. Memon ◽  
S. Sohu
Keyword(s):  
Flexural Strength ◽  
Concrete Beams ◽  
Testing Machine ◽  
Maximum Load ◽  
Reinforced Concrete Beams ◽  
Recycled Aggregates ◽  
Equal Proportion ◽  
Load Testing ◽  
Coarse Aggregates ◽  
Natural Aggregates

In this article, the effect of prolonged fire (24-hour duration) on reinforced concrete beams made with recycled aggregates from demolished concrete was experimentally investigated. Demolished concrete was used recycled coarse aggregates in equal proportion with natural coarse aggregates. Normal and rich mix concrete with water-cement ratio equal to 0.54 were used. As a control specimen, beams with all-natural aggregates were also cast to compare with the results of the proposed beams. All beams were cured for 28 days and exposed to fire at 1000°C in an oven for 24 hours. After the elapse of this fire period, the beams were allowed to air cool, followed by testing till failure in a universal load testing machine. Comparison of the test results shows that rich mix concrete beams more reduction in flexural strength, more increase in maximum load carrying capacity and deflection than normal mix beams. The maximum reduction in flexural strength was 32.41% for beams cast with 50% RCA and rich mix. Although the fire duration used in this study is rare, yet the outcome provides guidelines for taking proper decisions for retrofitting/strengthening of the fire affected structure before putting it back in service.

scholarly journals Experimental and Simulation Investigation of Bending Moment Effect on Hollow Columns of Multi-layers of Hybrid Materials

2019 ◽  
Vol 12 (1) ◽  
pp. 44-55
Author(s):  
Ayad A. Ramadhan
Keyword(s):  
Hybrid Materials ◽  
Volume Fraction ◽  
Load Capacity ◽  
Testing Machine ◽  
Bending Moment ◽  
Maximum Load ◽  
Experimental Procedure ◽  
Bending Load ◽  
Alumina Composite ◽  
Moment Effect

This paper presented the effect of bending on multi-layer of hollow columns of Hybrid materials (Carbon-Glass /epoxy-Alumina) composite this effect occurred and volume fraction of fibers. An experimental procedure was developed to study the performance of these effects under bending load using a hydraulic bending device type (MATEST. SRL) testing machine. This study has three forms through the selection of columns hollows width to thickness (a/b) (0.5, 1 and 2) with three types of layers of samples (2,4 and8) layers. The ultimate load of failure for each Hybrid/epoxy-Al2O3 had been determined and specified the optimum volume fraction (Vf) due to the effect of mixing 50% and 60% were low in the case for compared 55% volume fraction. To simulate this problem the researcher used Explicit Mesh for AUTODYN under ANSYS-15 software, it was found that maximum bending load for Hybrid/ Epoxy-Al2O3 Specimens, the maximum load of specimens increased with increasing number of layers from 2L to 8L. The results also identified that the maximum load capacity by 55% volume fraction and a/b=0.5 of all composite specimens was highest from the others types of (50% and 60%) volume fractions and (a/b=1 and a/b=2) .Also, the Increasing ratio of stress capacity for specimens have 4 to 2 layers (4/2)  and 8 to 4  (8/4) for experimental results have maximum value with increasing by 48.19%  and 46.84% at (Sp.4#8/Sp.2#4) and (Sp.8#6/Sp.4#6) respectively.

scholarly journals Accuracy and Feasibility of Clinically Applied Frailty Instruments before Surgery

2020 ◽  
Vol 133 (1) ◽  
pp. 78-95 ◽  
Author(s):  
Sylvie D. Aucoin ◽  
Mike Hao ◽  
Raman Sohi ◽  
Julia Shaw ◽  
Itay Bentov ◽  
...  
Keyword(s):  
Odds Ratio ◽  
Primary Outcome ◽  
Cochrane Library ◽  
Patient Centered ◽  
Clinical Frailty Scale ◽  
Frailty Phenotype ◽  
Random Effects Models ◽  
The Individual ◽  
Meta Analyses ◽  
Instrument Level

Background A barrier to routine preoperative frailty assessment is the large number of frailty instruments described. Previous systematic reviews estimate the association of frailty with outcomes, but none have evaluated outcomes at the individual instrument level or specific to clinical assessment of frailty, which must combine accuracy with feasibility to support clinical practice. Methods The authors conducted a preregistered systematic review (CRD42019107551) of studies prospectively applying a frailty instrument in a clinical setting before surgery. Medline, Excerpta Medica Database, Cochrane Library and the Comprehensive Index to Nursing and Allied Health Literature, and Cochrane databases were searched using a peer-reviewed strategy. All stages of the review were completed in duplicate. The primary outcome was mortality and secondary outcomes reflected routinely collected and patient-centered measures; feasibility measures were also collected. Effect estimates were pooled using random-effects models or narratively synthesized. Risk of bias was assessed. Results Seventy studies were included; 45 contributed to meta-analyses. Frailty was defined using 35 different instruments; five were meta-analyzed, with the Fried Phenotype having the largest number of studies. Most strongly associated with: mortality and nonfavorable discharge was the Clinical Frailty Scale (odds ratio, 4.89; 95% CI, 1.83 to 13.05 and odds ratio, 6.31; 95% CI, 4.00 to 9.94, respectively); complications was associated with the Edmonton Frail Scale (odds ratio, 2.93; 95% CI, 1.52 to 5.65); and delirium was associated with the Frailty Phenotype (odds ratio, 3.79; 95% CI, 1.75 to 8.22). The Clinical Frailty Scale had the highest reported measures of feasibility. Conclusions Clinicians should consider accuracy and feasibility when choosing a frailty instrument. Strong evidence in both domains support the Clinical Frailty Scale, while the Fried Phenotype may require a trade-off of accuracy with lower feasibility. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

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