contact

摘要： Microbes inhabit every surface, reproduce, and if undisturbed, could form biofilm. Hospital contact surfaces have been reported to play a major role in the spread of healthcare-acquired infections (HAIs). Most studies on these surfaces as a route for the spread of nosocomial infections have focused on the high-contact surfaces. There is a paucity of information on the bioburden of “neglected” low-contact surfaces such as bedside bible, ward television, and ward clock, etc. This study was carried out to investigate the bioburden of “neglected” low-contact hospital surfaces and compare it with that of the high-contact surfaces. Using a sterile swab stick moistened in normal saline, we collected 400 samples from contact surfaces of 20 randomly selected hospitals in Owerri, southeast in Nigeria, and by standard microbiological methods and with reference to standard identification manuals, microbial species were isolated and characterized. The results show that the mean of the bioburden in cfu/square swabbed surface of these “neglected” low-contact surfaces is significantly higher (p = 0.005) than that of the high-contact surfaces which may be a result of target hygienic cleaning, with attention on the high-contact surfaces and the low-contact surfaces are often “neglected”. This result gives an insight into the continued prevalence of hospital-acquired infections as these “neglected” low-contact surfaces continue to serve as a reservoir for pathogenic microbes and a source of continued microbial contamination of hospital surfaces. It therefore calls for a revamp of existing hospital cleaning protocols and redesigning of cleaning regimes.

摘要： In discontinuous computations,contacts between two general blocks A and B are common and represent a fundamental problem.This paper presents a mathematically proven theory and algorithm to address this problem.In the proposed approach,a reference point a0 is selected from block A,and the contacts between blocks A and B are transferred to the contact of the reference point a0 and the entrance block E(A,B).Discontinuity related computations DEM,DDA,and FEM can use this mathematically proven theory and algorithm directly.

摘要： The second wave of COVID-19 pandemic has started globally, right now 220 countries are infected and a total of 71,351,695 confirmed cases and 1,612,372 deaths due to COVID-19 have been reported. Infection Prevention and Control (IPC) measures for COVID-19 all have proved vital in decreasing the transmission rates among the communities. Methodology: Unmatched Case-Control Study was conducted where cases were defined as “every PCR positive contact (symptomatic or asymptomatic) for any index case” similarly controls were defined as “every PCR negative contact (symptomatic or asymptomatic) for any index case who was home quarantined for 14 days based on suspicion by PDSRU team”. A simple random technique was used and 300 individuals were made part of this study. Results: The major findings of this study shows that PCR positive contacts poorly adopted certain COVID-19 IPC measures of interest in their daily life hence got infected. The odds for all the variables of interest were found to be statistically significant among cases as compared to controls like the odds for knowingly and intentionally contacted with a COVID-19 positive case was 13.7 times more among the PCR positive contacts as compare to PCR negative contacts (p = 0.00, C.I = 7.62 - 24.90), similarly, the odds of being a family member of the index COVID-19 case was 7.07 times more among the PCR positive contacts as compared to the PCR negative contacts (p = 0.00, C.I = 3.25 - 15.86). Conclusion: Before the development and availability of a vaccine, the only tools that can help prevent the spread of COVID-19 are IPC measures.

摘要： Background: Contact dermatitis is common disease and represents a significant problem in healthcare sector, mainly among nurses. Many studies reported the prevalence of contact dermatitis from different parts of the world. Nevertheless, data about its frequency in Tunisia especially in public hospital seems to be insufficient. This study aims to assess the prevalence of contact dermatitis among nurses working in public hospital and identify risk factors. Patient and Methods: A cross sectional study was conducted among a representative sample of 1278 health professionals working in a public hospital matched by professional status and department. The survey was based on a questionnaire, a specialized examination and patch tests. Results: The prevalence of occupational contact dermatitis was 22% (17.5 - 27.2). The worker profile at risk of contact dermatitis was a female nurse aged 37 years working in a surgical department during 12.7 ± 9.36 years. Hands were damaged in 92.4% of cases and rhythmicity with occupational exposure was reported by 86% of affected individuals. Patch tests using European Standard Battery were performed among 33 workers and revealed a sensitization to an allergen among 26 workers. Patch test using rubber battery (if suspicion of allergic contact dermatitis to gloves) was performed among 29 agents and positive among 12. The analytical study revealed that history of atopy, job tenure, the mean daily number of hand washing, the mean daily number of worn gloves and mean duration of glove wearing were significantly higher in the affected population. Conclusion: Contact dermatitis affects particularly nurses in public hospitals. Its prevention requires a diagnostic approach based on a detailed professional investigation and patch tests.

摘要： The carrier transport mechanism of Mg/Au ohmic contact for lightly doped β-Ga_2O_3 is investigated. An excellent ohmic contact has been achieved when the sample was annealed at 400 °C and the specific contact resistance is 4.3 × 10-4 Ω·cm2. For the annealed sample, the temperature dependence of specific contact resistance is studied in the range from 300 to 375 K. The specific contact resistance is decreased from 4.3 × 10-4 to 1.59 × 10-4 Ω·cm2 with an increase of test temperature. As combination with the judge of E00, the basic mechanism of current transport is dominant by thermionic emission theory. The effective barrier height between Mg/Au and β-Ga_2O_3 is evaluated to be 0.1 eV for annealed sample by fitting experimental data with thermionic emission model.

摘要： The results of the tests for a friction pair “a cylindrical specimen made of 0.45% carbon steel—a counter specimen-liner made of polytetrafluoroethyleneF4-B” during sliding friction are presented. The test results at different levels of contact load are analyzed using the Archard’s equation and are presented as a friction fatigue curve. The concept of the frictional stress intensity factor during sliding friction is introduced, and an expression that relates the wear rate to this factor and is close in shape to the Paris equation in fracture mechanics is proposed.

摘要： In this paper, we consider with the large time behavior of solutions of the Cauchy problem to the one-dimensional compressible micropolar fluid model, where the far field states are prescribed. When the corresponding Riemann problem for the Euler system admits the solution consisting of contact discontinuity and rarefaction waves, it is shown that the combination wave corresponding to the contact discontinuity, with rarefaction waves is asymptotically stable provided that the strength of the combination wave and the initial perturbation are suitably small. This result is proved by using elementary L2-energy methods.

摘要： BACKGROUND The use of methyl-tertiary butyl ether(MTBE)to dissolve gallstones has been limited due to concerns over its toxicity and the widespread recognition of the safety of laparoscopic cholecystectomy.The adverse effects of MTBE are largely attributed to its low boiling point,resulting in a tendency to evaporate.Therefore,if there is a material with a higher boiling point and similar or higher dissolubility than MTBE,it is expected to be an attractive alternative to MTBE.AIM To determine whether tert-amyl ethyl ether(TAEE),an MTBE analogue with a relatively higher boiling point(102°C),could be used as an alternative to MTBE in terms of gallstone dissolubility and toxicity.METHODS The in vitro dissolubility of MTBE and TAEE was determined by measuring the dry weights of human gallstones at predetermined time intervals after placing them in glass containers with either of the two solvents.The in vivo dissolubility was determined by comparing the weights of solvent-treated gallstones and control(dimethyl sulfoxide)-treated gallstones,after the direct infusion of each solvent into the gallbladder in both hamster models with cholesterol and pigmented gallstones.RESULTS The in vitro results demonstrated a 24 h TAEE-dissolubility of 76.7%,56.5%and 38.75%for cholesterol,mixed,and pigmented gallstones,respectively,which represented a 1.2-,1.4-,and 1.3-fold increase in dissolubility compared to that of MTBE.In the in vitro experiment,the 24 h-dissolubility of TAEE was 71.7%and 63.0%for cholesterol and pigmented gallstones,respectively,which represented a 1.4-and 1.9-fold increase in dissolubility compared to that of MTBE.In addition,the results of the cell viability assay and western blot analysis indicated that TAEE had a lower toxicity towards gallbladder epithelial cells than MTBE.CONCLUSION We demonstrated that TAEE has higher gallstone dissolubility properties and safety than those of MTBE.As such,TAEE could present an attractive alternative to MTBE if our findings regarding its efficacy and safety can be consistently reproduced in further subclinical and clinical studies.

摘要： Correlations for the extension of a water vapor jet injected in a liquid pool were historically proposed considering the mass flux (kg/m2/s) as a constant. The results were satisfactory, however adjusting the values by linear regression. Although, it presents the following drawbacks: 1) the formulation is only valid for the specific range of data for what it was created;2) it does not allow the analytical evaluation of the heat transfer coefficient from the extension equation. This paper proposes a new formulation for the calculation of the mass flux, in such a way to remove both of these drawbacks.

摘要： Through the rolling contact fatigue experiment under the condition of the lubricating oil, this article investigated the relation between contact fatigue property and microstructure on the surface layer of D2 wheel steel. The results showed that although the roughness of the original specimen induced by mechanical processing would diminish to some extent in the experiment, the 0.5 - 1.5 μm thick layer of ultrafine microstructure on the original mechanically-processed specimen surface would still become micro-cracks and small spalling pits due to spalling, and would further evolve into fatigue crack source. Additionally, even under the impact of the load that was not adequate to make the material reach fatigue limit, the ferrite in the microstructure underwent plastic deformation, which led the refinement of proeutectoid ferrite grains. During the experiment, the hardening and the refinement caused by plastic deformation consisted with the theory that dislocation gave rise to plastic deformation and grain refinement. The distribution laws of hardness and ferrite grain sizes measured could be explained by the distribution law of the shearing stress in the subsurface.