Multi criteria decision making for optimal below knee prosthetic design

In manufacturing prostheses such as blow knee (BK) prostheses, the designer needs to make a proper selection of materials to achieve some requirements according to patient uses prior to fabricating the parts of the prosthesis. Some requirements are low cost, lightweight, durable and withstand the loading environment. Different methods have been used to make such selections based on the optimisation of material properties such as statistical, graphical and computer software. The selection of the optimal material for the socket, shank and foot of BK prostheses is thus considered in this work using the multi-criterion decision-making (MCDM) technique. One of the MCDM strategies is TOPSIS, which was used to choose the ideal material and make a recommendation to design BK prosthesis under different conditions. The common materials used for socket, shank and foot are collected from research works as reference data including polymers, composite, metal alloys, and wood. The results show that pineapple fibre-reinforced composite (PFRC) composite provides light and stiff socket, and PFRC composite provides elastic thought sockets. Titanium alloy (Ti-6Al-4V) provides a stiff shank, and stainless steel (SS 304) alloy provides shock resist shank. Hardwood can be used for low-cost foot, and carbon fibre for shock resistance foot

The Effect of Additives on The Performance of HydrostaticThrust Bearings

The paper is concerned with, the behavior of the hydrostatic thrust bearings lubricated with liquid-solid lubricants using Einstein viscosity formula, and taking into account the centrifugal force resulting from high speed. Also studied is the effect of the bearing dimensions on the pressure, flow rate, load capacity, shear stress, power consumption and stiffness. <br />The theoretical results show an increase in load capacity by (8.3%) in the presence of solid graphite particles with concentration of (16%) by weight as compared with pure oil, with increasing shear stress. . <br />In general the performance of hydrostatic thrust bearings improve for load carrying capacity, volume flow rate, pumping power subjected to centrifugal parameter (S), recess position (r1), film thickness ratio (&#61538;), particle concentration (&#61548;).<br /

Theoretical and Experimental Investigation of Transient Temperature Distribution in Friction Stir Welding of AA 7020-T53

Finite element modeling of transient temperature distribution is used to understand physical phenomena occurring during the dwell (penetration) phase and moving of welding tool in friction stir welding (FSW) of 5mm plate made of 7020-T53 aluminum alloy at 1400rpm and 40mm/min. Thermocouples are used in locations near to the pin and under shoulder surface to study the welding tool penetration in the workpiece in advance and retreate sides along welding line in three positions (penetrate (start welding) , mid, pullout (end welding)). Numerical results of ANSYS 12.0 package are compared to experimental data including axial load measurements at different tool rotational speeds (710rpm.900rpm.1120rpm and 1400rpm) Based on the experimental records of transient temperature at several specific locations of thermocouples during the friction stir welding process the temperatures are higher on the advancing side (629.2 oK) than the retreating side (605 oK) along welding line and temperature in the top of workpiece under tool shoulder is higher(645 oK) than bottom (635.79oK). The results of the simulation are in good agreement with that of experimental results. The peak temperature obtained was 70% of the melting point of parent metal

Synthesis and spectroscopic studies of new leucine acid derivative with their metal complexes.

A new ligand N-[(acetyl amino)-thioxo methyl]leucine(ATL) are synthesized by reaction of acetyl-isothio cyanate with leucine acid. The ligand is characterized by elemental analysis, FT-IR and NMR spectra, some transition metal complex of this ligand were prepared and characterized by FT-IR, UV-visible spectra, conductively measurements, magnatic suscpility, atomic absorption and determination of molar ration(M:L). from results obtained, the following formaula [M(ATL)2] where M+2 =(Mn, Fe, Co, Ni, Cu, Zn, Cd and Hg) and the proposed molecular structure for these complexes as tetrahedral geometry

The behaviour of different design of flexible force sensor based velostat during implementation of static load with different contact area

Great attention has been given to flexible force sensors and the materials that have been used as a sensing material by studying their properties and evaluate their behaviours with different types of loads. Velostat is one of the most promising sensing materials that has been widely studied and evaluated for different applications due to their distinct traits of flexibility, suitable cost as well as their ability to cover the wearable applications. This work makes focus on the behaviour of Velostat flexible force sensor by measuring the resistivity of the sensor while applying loads with different contact area. Two different designs of sensor have been studied, which are the single output flexible force sensor and multioutput matrix flexible force sensor, by applying loads starting from 0.98 (N) to 9.8 (N) with four compression disc having different diameters. It has been found that the two design behave in opposite manner. The resistance of the single output design decreased as the contact area increased, while the matrix design showed an increasing in the resistance as the contact area increased

Isolation and Identification of Polioviruses from Stool Specimens of Suspected Cases

Background: To study the isolation and identification of polioviruses from the stool specimen of suspected cases of poliomyelitis (polio). Methods : In this descriptive study two poliovirus-sensitive cell lines of human origin HEp-2, and RD were used for poliovirus isolation. Two hundred and two samples of stool specimen were processed according to the WHO recommendations. Supernatant of stool specimen were inoculated on HEp-2, and RD for poliovirus culture, and incubated at 36oC. Cultures were initially set up in growth medium supplemented with serum. After the formation of a confluent monolayer from the cells, cultures were changed to maintenance medium, designed to maintain cultures in healthy state without stimulating growth. The tubes were incubated , and put in racks at inclined angle of 5o , with line (blue for HEp-2, and black for RD cell line) of tube in upper position. Cultures were daily examined for color change from pinkish to yellow, and for appearance of cytopathic effects (CPEs) under the inverted microscope for 10-14 days before discarding as negative. The yellowish coloration indicated the absence of poliovirus while no color change was indicative of presence of poliovirus, and presence of characteristic CPEs production of poliovirus i.e. rounding of cells, and detachment of cells from culture tubes. Tubes showing CPEs were stored at -20oC. Identification of poliovirus isolates was done by mixing the diluted isolates samples, with equal volumes of a set of antisera of known poliovirus serotypes. The antiserum/ poliovirus mixture was incubated for 2 hr to allow binding of antibodies to poliovirus. Afterwards the mixtures were inoculated into cell culture tubes, and examined daily for CPEs. Prevention of the development of CPEs by the specific antiserum, indicated the identity of the poliovirus serotype. The identification of both isolates from RD as well as Hep-2 cell cultures, was carried on as poliovirus susceptibility of these two lines varies.Results: Majority of cases(38.1%) were of 3-12 months, followed by 13-24 months (34.6%). Male to female ratio was 1.4:1.0. Among the suspected cases, 94% were vaccinated, while about 2% were partially vaccinated. Poliovirus was isolated from 28.2% stool specimens of suspected cases of polio. The poliovirus type 1 was found 75.4%, one of the most common among positive cases. 35% cases were found from Punjab and 28% from KPKConclusion: Most prevalent type of poliovirus is type-1, and the maximum number of polio is found in the province Punjab. The most vulnerable age group for polio was 3-12 months, and the target age less than 5 years, that covered the percentage of total number of cases upto 99%. Moreover, 94.06% cases of polio were unvaccinated

Isolation and Identification of Polioviruses from Stool Specimens of Suspected Cases

Background: To study the isolation and identification of polioviruses from the stool specimen of suspected cases of poliomyelitis (polio). Methods : In this descriptive study two poliovirus-sensitive cell lines of human origin HEp-2, and RD were used for poliovirus isolation. Two hundred and two samples of stool specimen were processed according to the WHO recommendations. Supernatant of stool specimen were inoculated on HEp-2, and RD for poliovirus culture, and incubated at 36oC. Cultures were initially set up in growth medium supplemented with serum. After the formation of a confluent monolayer from the cells, cultures were changed to maintenance medium, designed to maintain cultures in healthy state without stimulating growth. The tubes were incubated , and put in racks at inclined angle of 5o , with line (blue for HEp-2, and black for RD cell line) of tube in upper position. Cultures were daily examined for color change from pinkish to yellow, and for appearance of cytopathic effects (CPEs) under the inverted microscope for 10-14 days before discarding as negative. The yellowish coloration indicated the absence of poliovirus while no color change was indicative of presence of poliovirus, and presence of characteristic CPEs production of poliovirus i.e. rounding of cells, and detachment of cells from culture tubes. Tubes showing CPEs were stored at -20oC. Identification of poliovirus isolates was done by mixing the diluted isolates samples, with equal volumes of a set of antisera of known poliovirus serotypes. The antiserum/ poliovirus mixture was incubated for 2 hr to allow binding of antibodies to poliovirus. Afterwards the mixtures were inoculated into cell culture tubes, and examined daily for CPEs. Prevention of the development of CPEs by the specific antiserum, indicated the identity of the poliovirus serotype. The identification of both isolates from RD as well as Hep-2 cell cultures, was carried on as poliovirus susceptibility of these two lines varies.Results: Majority of cases(38.1%) were of 3-12 months, followed by 13-24 months (34.6%). Male to female ratio was 1.4:1.0. Among the suspected cases, 94% were vaccinated, while about 2% were partially vaccinated. Poliovirus was isolated from 28.2% stool specimens of suspected cases of polio. The poliovirus type 1 was found 75.4%, one of the most common among positive cases. 35% cases were found from Punjab and 28% from KPKConclusion: Most prevalent type of poliovirus is type-1, and the maximum number of polio is found in the province Punjab. The most vulnerable age group for polio was 3-12 months, and the target age less than 5 years, that covered the percentage of total number of cases upto 99%. Moreover, 94.06% cases of polio were unvaccinated

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population

Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care. We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care