scholarly journals HUMAN FACTORS LEARNING CURVE FOR THUMB-OPERATED TRIGGER RIFLE USING GYROSCOPIC FEEDBACK INSTRUMENTATION

2021 ◽  
Vol 57 (2) ◽  
pp. 274-280
Author(s):  
David C. Paulus ◽  
Keyword(s):  
Human Factors ◽  
Learning Curve ◽  
Research Effort ◽  
Auditory Signal ◽  
Accuracy Score ◽  
Trigger System ◽  
Cycle Times ◽  
New Device ◽  
Significant Difference ◽  
Direction Of Movement

Researchers interested in evaluating the biomechanics and human factors associated with using a new product recognize that skill development with the novel design is time-dependent. A learning curve is a plot that shows the time to complete a task using the product decreases as the number of training repetitions increases. A novel thumb-operated trigger system (Iron Horse, Blackwater Worldwide™) has been developed for the AR-15 style rifle with the intent to shorten the learning curve. The purpose of this research effort is to quantify the learning curve for the new device and to compare it to that of a standard mil-spec AR-15 trigger system. A previously-trained shooter dry-fire trained with both rifle systems for twenty consecutive days alternating lower receivers each day. The rifles were equipped with a gyroscopic instrument (Mantis X™) that tracked the movement of the firearm during the trigger pull process. The instrument has a timer to record the reaction time to an auditory signal for each shot, records the magnitude and direction of movement of the firearm, and calculates an accuracy score. There was not a significant difference (p>0.05) between the thumb operated and mil-spec triggers’ cycle times. However, the accuracy scores with the thumb operated trigger were significantly higher (p<0.05) than those with the mil-spec trigger.

The Safety of the Esmarch Tourniquet

Foot & Ankle ◽  
1993 ◽  
Vol 14 (5) ◽  
pp. 278-283 ◽  
Author(s):  
William C. Biehl ◽  
James M. Morgan ◽  
F. William Wagner ◽  
Rodney A. Gabriel
Keyword(s):  
Learning Curve ◽  
Clinical Application ◽  
Medial Malleolus ◽  
Foot And Ankle ◽  
Surgical Case ◽  
Significant Difference ◽  
Mean Pressure ◽  
Continued Use

The use of an Esmarch bandage as a tourniquet in surgery has been criticized. Many authors claim that the pressures under the Esmarch are inconsistent and may be extremely high. We have seen few, if any, problems from the use of an Esmarch in surgery of the foot and ankle. The purpose of this study was to evaluate the pressures generated under the Esmarch tourniquet in a situation that mimics its clinical application, and to determine whether pressures of appropriate magnitude and consistency are obtained in order to recommend its continued use in surgery. Ten volunteers performed numerous applications of the Esmarch. The number of wraps and the width of the Esmarch bandage used were varied. The Esmarch was applied as it would be for a surgical case. Pressures directly beneath the Esmarch were recorded 8 cm proximal to the distal tip of the medial malleolus. Considering all volunteers and all pressures generated, a 3-in Esmarch applied with three wraps gave a mean pressure (±SD) of 225 ± 46 mm Hg. A 3-in Esmarch applied with four wraps gave a mean pressure of 291 ± 53 mm Hg. A 4-in Esmarch applied with three wraps gave a mean pressure of 233 ± 35 mm Hg, and a 4-in Esmarch with four wraps gave a mean pressure of 284 ± 42 mm Hg. The maximum pressures generated by any individual were as follows: 3-in three wraps, 321 mm Hg; 3-in four wraps, 413 mm Hg; 4-in three wraps, 328 mm Hg; and 4-in four wraps, 380 mm Hg. There was no significant difference in the magnitude or consistency of pressures generated between the experienced and inexperienced wrappers. There did not appear to be a learning curve for the application of the Esmarch bandage. We conclude that an Esmarch bandage, used as a tourniquet, can generate safe and reliable pressures. Either a 3-in or 4-in Esmarch bandage applied above the ankle with three circumferential overlapping wraps consistently results in pressures that are in a safe range.

scholarly journals HemoCue against Coulter LH-750 in the estimation of hemoglobin levels of blood donors in mobile collection settings: a comparative study

2018 ◽  
Vol 27 (4) ◽  
pp. 250-5
Author(s):  
Sultan A.M. Saghir ◽  
Amer A. Almaiman ◽  
Aishah K.A. Shatar ◽  
Norris Naim ◽  
Huda S. Baqir
Keyword(s):  
Blood Donors ◽  
Reference Method ◽  
Cross Sectional Study ◽  
Outpatient Setting ◽  
Concordance Correlation ◽  
Cross Sectional ◽  
New Device ◽  
Coefficients Of Variation ◽  
Significant Difference

Background: The fast and outpatient setting for a determination of the hemoglobin (Hb) level is a well-recognized prerequisite to detect anemia in blood donors. This study aimed to evaluate the performance of the HemoCue methods (HemoCue B-Hb and HemoCue-301) against Coulter LH-750 as a reference method for Hb determination.Methods: This study was an experimental cross-sectional study. It includes 455 blood samples that were collected from volunteer blood donors between January 15, 2010 and February 15, 2011. The performance of the three methods and their comparisons were assessed using the analysis of coefficients of variation (CV), linear regression, and mean difference. Correlation coefficient and Bland–Altman plots were drawn to compare the two HemoCue measurements and the automated cell analyzer against each other and to evaluate their results. The Hb concentrations were compared using the concordance correlation coefficient.Results: The findings exhibited that the CV for the three methods Coulter LH-750, HemoCue B-Hb, and HemoCue-301 were 0.60%, 0.72%, and 0.92%, respectively. A statistically significant difference was observed between the means of the Hb measurements for the three methods (p<0.001). The HemoCue B-Hb and HemoCue-301 methods showed the best agreement, and the Coulter LH-750 method gave a lower Hb value compared with the two HemoCue methods. The results showed a positive correlation of HemoCue Hb results compared with the reference method.Conclusion: All three methods provide a good agreement for Hb determination. The new device HemoCue-301 was found to be more accurate compared with HemoCue B-Hb and Coulter LH-750.

Changes in motor cortex activity during reaching movements with similar hand paths but different arm postures

1995 ◽  
Vol 73 (6) ◽  
pp. 2563-2567 ◽  
Author(s):  
S. H. Scott ◽  
J. F. Kalaska
Keyword(s):  
Motor Cortex ◽  
Sagittal Plane ◽  
Single Cells ◽  
Reaching Movements ◽  
Movement Direction ◽  
Tonic Activity ◽  
Population Vector ◽  
Significant Difference ◽  
Direction Of Movement ◽  
Kinematics And Kinetics

1. Neuronal activity was recorded in the motor cortex of a monkey that performed reaching movements with the use of two different arm postures. In the first posture (control), the monkey used its natural arm orientation, approximately in the sagittal plane. In the second posture (abducted), the monkey had to adduct its elbow nearly to shoulder level to grasp the handle. The path of the hand between targets was similar in both arm postures, but the joint kinematics and kinetics were different. 2. In both postures, the activity of single cells was often broadly tuned with movement direction and static arm posture over the targets. In a large proportion of cells, either the level of tonic activity, the directional tuning, or both, varied between the two postures during the movement and target hold periods. 3. For most directions of movement, there was a statistically significant difference in the direction of the population vector for the two arm postures. Furthermore, whereas the population vector tended to point in the direction of movement for the control posture, there was a poorer correspondence between the direction of movement and the population vector for the abducted posture. These observed changes are inconsistent with the notion that the motor cortex encodes purely hand trajectory in space.

scholarly journals Learning curve for the laparoscopy-guided kidney biopsy procedure in small corpses of dogs and pigs

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257653
Author(s):  
Suellen Rodrigues Maia ◽  
Pamela Almerinda Mendes ◽  
Felipe Farias Pereira da Câmara Barros ◽  
Ilan Munhoz Ayer ◽  
Salvador Boccaletti Ramos ◽  
...  
Keyword(s):  
Learning Curve ◽  
Kidney Biopsy ◽  
Random Effect ◽  
Total Duration ◽  
Qualitative Assessment ◽  
Swine Model ◽  
Significant Difference ◽  
Renal Biopsies ◽  
Mixed Regression ◽  
And Training

The use of renal biopsy through laparoscopy is increasingly present both in human and veterinary medicine. However, both techniques require skill and training to make the operator capable to do it. The learning curve allows the quantitative and qualitative assessment of the number of attempts and minimum time for the surgical procedure. The objective included establish the learning curve for laparoscopy-guided kidney biopsy procedures in dog and pig corpses. Six dogs and six pigs corpses weighing less than 10 kg were used for this study. All corpses underwent kidney biopsy performed through laparoscopy. Twenty-four operators, two per animal, performed 20 renal biopsies each (10 for each kidney), with 480 collection-procedures in total. Duration and difficulty of the procedure and the biopsy sample quality were evaluated and statistical analysis was performed using a mixed regression model with a random effect of individuals and multivariate analysis of data. There were 91.5% of the samples that were adequate for evaluation. There was no significant difference in the number of glomeruli or cortex percentage considering the attempts in either species, demonstrating the operator’s ability since first collection. Swine samples showed higher amounts of renal cortex than canine samples. The procedure duration was shorter as more attempts were performed in dogs and pigs. From the fourth repetition, the professional reached a plateau for the variable related to ‘collection’, and from the second, the professional presented uniform duration for ‘sample storage’. Operators of the swine model acquired more agility than the dog ones. The variable ‘difficulty’ decreased as more repetitions were performed, reaching a plateau in the sixth attempt. Seven renal biopsies laparoscopy-guided are required for an operator to be considered ‘capable’ to perform the procedure in the referred species included. The learning curve for image-guided kidney biopsy procedures improves the implementation of this technique and benefits patients that undergo this procedure.

scholarly journals O12 OPEN PREPERITONEAL INGUINAL HERNIA REPAIR, TREPP VERSUS TIPP IN A RANDOMIZED CLINICAL TRIAL

2021 ◽  
Vol 108 (Supplement_8) ◽  
Author(s):  
Willem Bökkerink ◽  
Giel Koning ◽  
Patrick Vriens ◽  
Roland Mollen ◽  
Willem Akkersdijk ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Inguinal Hernia ◽  
Hernia Repair ◽  
Learning Curve ◽  
Randomized Clinical Trial ◽  
Inguinal Hernia Repair ◽  
Recurrence Rates ◽  
Significant Difference ◽  
Related Quality

Abstract Aim The preperitoneal mesh position for inguinal hernia repair showed beneficial results regarding Chronic Postoperative Inguinal Pain (CPIP) with low recurrence rates. Two open preperitoneal techniques, the TransREctus Sheath PrePeritoneal (TREPP) and the TransInguinal PrePeritoneal (TIPP) technique, were compared in a randomized clinical trial with the hypothesis of less patients with CPIP after TREPP due to complete avoidance of nerve contact. Materials and Methods Adult patients with a primary unilateral inguinal hernia were randomized to either TREPP or TIPP in four hospitals. Prior to the trial’s start the study protocol was ethically approved and published. Outcomes included CPIP after 1 year (primary outcome) and recurrence rates, adverse events and Health related Quality of Life (secondary outcomes). Follow-up was performed at 2 weeks, 6 months and 1 year. Results Baseline characteristics were comparable in both groups. Pain was less often present after TREPP at 2 weeks and 6 months, but the CPIP at rest at 1 year was comparable 1.9% after TREPP vs 1.4% after TIPP, p = 0.535). The overall recurrence rate was higher in the TREPP group, 8.9% vs 4.6%, p = 0.022). Corrected for a learning curve for TREPP, no significant difference could be assessed (TREPP 5.7% and TIPP 4.8%, p = 0.591). Conclusions both the TREPP and TIPP technique resulted in a low incidence of CPIP after 1 year follow-up. The TREPP method can be considered a solid method for inguinal hernia repair if expertise is present. The learning curve of the TREPP techniques needs further evaluation.

scholarly journals Total hip arthroplasty performed by direct anterior approach – Does experience influence the learning curve?

SICOT-J ◽  
2020 ◽  
Vol 6 ◽  
pp. 15 ◽  
Author(s):  
Constant Foissey ◽  
Mathieu Fauvernier ◽  
Cam Fary ◽  
Elvire Servien ◽  
Sébastien Lustig ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Learning Curve ◽  
Hip Arthroplasty ◽  
Anterior Approach ◽  
Operating Time ◽  
Surgical Techniques ◽  
Direct Anterior Approach ◽  
Clinical Results ◽  
Total Hip ◽  
Significant Difference

Introduction: Proficiency in the direct anterior approach (DAA) as with many surgical techniques is considered to be challenging. Added to this is the controversy of the benefits of DAA compared to other total hip arthroplasty (THA) approaches. Our study aims to assess the influence of experience on learning curve and clinical results when transitioning from THA via posterior approach in a lateral position to DAA in a supine position. Methods: A consecutive retrospective series of 525 total hip arthroplasty of one senior and six junior surgeons was retrospectively analysed from May 2013 to December 2017. Clinical results were analysed and compared between the two groups and represented as a learning curve. Mean follow up was 36.2 months ± 11.8. Results: This study found a significant difference in complications between the senior and junior surgeons for operating time, infection rate, and lateral femoral cutaneous nerve (LFCN) neuropraxia. A trainee’s learning curve was an average of 10 DAA procedures before matching the senior surgeon. Of note, the early complications correlated with intraoperative fractures increased with experience in both groups. Operating time for the senior equalised after 70 cases. Dislocation rate and limb length discrepancy were excellent and did not show a learning curve between the two groups. Conclusion: DAA is a safe approach to implant a THA. There is a learning curve and initial supervision is recommended for both seniors and trainees. Level of evidence: Retrospective, consecutive case series; level IV.

Evaluation of a New Device for Rapidly Separating Serum or Plasma from Blood

1974 ◽  
Vol 20 (12) ◽  
pp. 1573-1576 ◽  
Author(s):  
James C Mathies
Keyword(s):  
Lactate Dehydrogenase ◽  
Clinical Chemistry ◽  
Chemistry Laboratory ◽  
Significance Level ◽  
New Device ◽  
Paired Samples ◽  
Significant Difference ◽  
Clinical Chemistry Laboratory ◽  
Sufficient Magnitude ◽  
Student’S T

Abstract I have evaluated the suitability of a new device for the rapid and efficient separation of cell-free serum or plasma from whole blood. Thirty-four clinical chemistry procedures were used in the analysis of 750 paired blood samples. One sample from each pair was processed by double centrifugation, the other by single centrifugation with the new device. Differences between means for the paired samples were evaluated by Student's t-test. At a significance level of P ≤ 0.05, only uric acid, lactate dehydrogenase, lactate dehydrogenase isoenzyme 2, and CO2 show a statistically significant difference between the two separation procedures. These differences do not appear to be of sufficient magnitude to preclude use of the device in the clinical chemistry laboratory.

Single Screw vs. Double Screw Device for Use in Treating Femoral Bone Fractures

2010 ◽  
Author(s):  
J. E. Ondrake ◽  
K. C. Lifer ◽  
S. P. Haman ◽  
J. E. Marquart ◽  
Hui Shen
Keyword(s):  
Bone Fractures ◽  
Torsional Stiffness ◽  
Technical Problems ◽  
New Device ◽  
Fracture Surfaces ◽  
Single Screw ◽  
Femur Fractures ◽  
Force Relaxation ◽  
Significant Difference ◽  
Hip Screw

Proximal femur fractures commonly occur between the head of the femur and the femoral shaft. As the third most common injury encountered in orthopedic clinics, these fractures are typically treated with medical implants creating internal stabilization of the bone. Over 100 different implants are available for this application. Although the optimal choice for the implants is still controversial, traditional devices which include a single cylindrical screw, such as SHS (Sliding Hip Screw) and IMHS – CP (Intramedullary Hip Screw, Clinically Proven), are widely used to repair the bone fracture. However, the application of the single screw device still suffers technical problems. The head of the femur has the potential to rotate about the screw and the fracture surfaces have potential to slide over each other. In addition, force relaxation can occur, leading to inadequate contact between the fracture surfaces. To attack these problems and prevent possible complications, a new device has been developed. The new device consists of one long screw interlocked with one short screw, creating a cross-sectional figure-eight pattern and offering an integrated, interlocking screw option. The objective of the current study is to compare biomechanical characteristics within the bone caused by the new double screw device verses the traditional single screw device. Experiments were preformed to compare the torsional stiffness of the two devices. 2D and 3D finite element analysis methods were carried out to obtain macroscopic and microscopic responses of each device’s interaction with the fractured bone. The modeled results show a significant difference between the two geometries. The single screw geometry has higher maximum total deformation, equivalent strain, equivalent von Mises stress, and maximum principle stress. The improved rotational stability of the new double screw device may reduce the complication rate of instability of the fracture fragments.

scholarly journals Prototype of a new tip developed to be coupled to dental light-curing units for optimizing bonding of orthodontic brackets and accessories

2013 ◽  
Vol 18 (6) ◽  
pp. 112-116
Author(s):  
Sergio Luiz Mota Júnior ◽  
Márcio José da Silva Campos ◽  
Marco Abdo Gravina ◽  
Marcelo Reis Fraga ◽  
Robert Willer Farinazzo Vitral
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Light Exposure ◽  
Orthodontic Brackets ◽  
Light Refraction ◽  
New Device ◽  
Halogen Light ◽  
Significant Difference ◽  
Light Curing

OBJECTIVE: development of a new device to be coupled to light-curing units for bonding orthodontic brackets and accessories, and test its efficacy in an in vitro mechanical trial. The inner surface of the device is mirrored and is based on physical concepts of light refraction and reflection. The main advantage of such device is the reduced clinical time needed for bonding and the low possibility of contamination during the process. METHODS: One hundred and twenty specimens were used for testing the shear bond strength of brackets bonded with the device. The Adhesive Remnant Index (ARI) was also determined. The sample was divided into 2 groups. In group 1 a halogen light-curing unit was used while in group 2 a led light-curing unit was used. Each group was then subdivided. In subgroups H1 and L1, a conventional light guide rod was used while in subgroups H2 and L2 bonding was performed with the mirrored device coupled to the tip of the guide light rod. RESULTS: The values obtained for the shear bond strength and the ARI in the subgroups were compared. Results showed that there was no statistically significant difference for the shear strength (p > 0.05) and the ARI (p > 0.05) between the subgroups. CONCLUSION: The tests of mechanical trials and the ARI analysis showed that the new device fulfilled the requirements for bonding orthodontic accessories, and that the time for bonding was reduced to half, being necessary only one light exposure.

scholarly journals Clinical agreement and interchangeability of TEG5000 and TEG6s during cardiac surgery

2020 ◽  
Vol 48 (1) ◽  
pp. 43-52
Author(s):  
Qi Wong ◽  
Kelly P Byrne ◽  
Scott C Robinson
Keyword(s):  
Cardiac Surgery ◽  
Reaction Time ◽  
Alpha Angle ◽  
Maximum Amplitude ◽  
Surgical Patients ◽  
Treatment Recommendation ◽  
New Device ◽  
Management Algorithm ◽  
Arterial Blood ◽  
Significant Difference

TEG6s® is a new device introduced by the Haemonetics Corporation and designed to provide the same information as TEG® 5000 (Haemonetics Corporation, Braintree, MA, USA) but with much greater ease of use. We tested whether using citrated TEG6s gave reaction time, maximum amplitude and percentage of clot that had lysed at 30 minutes values similar to a non-citrated TEG5000, to allow clinical interchangeability using our current thrombelastography management algorithm for cardiac surgery. We also examined the agreement between the alpha-angle and functional fibrinogen maximum amplitude in our cardiac surgical patients.  In total, 243 paired arterial blood samples in 99 patients were tested, using TEG5000 (non-citrated) and TEG6s (citrated) after induction of anaesthesia (prior to heparin administration), following protamine administration at the end of the cardiac bypass and whenever a TEG5000 was requested after this by the attending anaesthetist. Bland–Altman plots and Lin’s concordance coefficient were used to compare agreement whereas modified Bland–Altman plots and McNemar’s test were used to illustrate the differences in management recommendations between the two thrombelastography devices.  All 243 samples were compared for reaction time and alpha-angle; 239 samples were compared for maximum amplitude; 136 samples were compared for the percentage of clot that had lysed at 30 minutes; 16 samples were compared for functional fibrinogen maximum amplitude. Lin’s concordance coefficient for these parameters was: reaction time 0.63, alpha-angle 0.39, maximum amplitude 0.5, percentage of clot that had lysed at 30 minutes 0.09 and functional fibrinogen maximum amplitude 0.31. Differences between the two devices became more marked at more abnormal values. Significant differences in median values, suggesting a fixed bias, were found for maximum amplitude and functional fibrinogen maximum amplitude. Differences in treatment recommendation could only be calculated for reaction time and maximum amplitude. Maximum amplitude was found to have a significant difference in treatment recommendation between the two devices using our current thrombelastography management algorithm for cardiac surgery with TEG6s recommending treatment in 11.5% more patients than TEG5000.  Using the TEG6s with our current TEG5000–based thrombelastography management algorithm for cardiac surgery would result in a change in treatment recommendation in at least 10% of our cardiac surgical patients. Agreement between the two thrombelastography devices appears to decrease with increasing patient coagulopathy. New algorithms will need to be developed and tested to validate TEG6s for cardiac surgical patients in our institution.

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