A comparative study of early-delayed skin grafting and late or non-grafting of deep partial thickness burns at the University Teaching Hospital

Objectives: To demonstrate the benefits of performing a split skin graft within 15 days post burn and explore thedifferences in duration of hospital stay, occurrence of infection and contracture formation in comparison to standard care currently provided at U.T.H (late or non split skin graft).Design: This was a prospective, non-randomized, interventional study involving patients with deep partial thickness burn wounds at UTH. Study subjects were to either receive an early-delayed skin graft, or the standard treatment at the time based on the surgical firm to which they were admitted.Results: Forty-three (55.1%) patients allocated to receive an early-delayed ssg while 35 (44.9%) were assigned to the late or non-ssg group. The proportion of males was 23 (29.5%) in the early-delayed group and 22 (28.2%) in the late or non ssg group while the proportion of females was 20 (25.6%) in the early-delayed group and 13 (16.7%) in the late or non ssg group. The participants' age range was 2 months to 84 years. Forty-nine (62.8%) were 5 years and below, eight (10.3%) were aged 6-10 years, ten (12.8%) were aged 11-20 years, and eleven (14.1%) were aged 21 and above years. The following were the main causes of burns, in their order of frequency, hot water (57%), flames (27%), hot food (i.e. cooking oil, porridge, beans [14%]), and chemicals (1%). In both groups the most common cause for burns was hot water, 19 (24%) in the earlydelayed skin graft group and 26 (33%) in the late or non ssg group. In forty seven (60%) patients burns were observed to affect multiple regions of the body. Mean total body surface area burn was 14%. Overall, 73 patients (93.6%) came from within Lusaka. It was also noted that 39(50%) were self referrals. Overall, 86% presented to the hospital within 24 hrs but  despite early presentation participants were reluctant to recieve an early skin graft due to lack of understanding of the procedure. Findings of this study found that at significance levels of 0.05 in the late or non SSG group hospital stay was significantly longer, (U = 305.500; p = 0.001) and infection higher (Chi Square = 4.510; p = 0.034).No significant difference was noted in contracture formation in the two groups (Chi square = 0.999; p = 0.258).Conclusions: Early–delayed split skin graft was found to statistically significantly reduce length of stay and occurence of infection as opposed to late or non ssg.No statistically significant relation could be established for occurence of contractures due to loss in follow up of patient valuable information was lost. This study shows that  even if early delayed SSG were to be offered at UTH there is need to carry out awareness campaigns to change  peoples attitudes towards the surgical procedure (SSG). This is an approved treatment world-wide which has not  gained wide acceptance amongst patients presenting to U.T.H that participated in this study. Patient attitudes and perceptions need to be changed as SSG currently is not seen as a curative treatment but as added injury to an  already injured patient.This study showed that SSG is possible and the few patients who underwent early grafting  showed good outcomes, shorter hospital stay and lower infection rates. Reduction in contracture formation may  have been determined if follow up was achieved

Backward-facing step measurements at low Reynolds number, Re(sub h)=5000

An experimental study of the flow over a backward-facing step at low Reynolds number was performed for the purpose of validating a direct numerical simulation (DNS) which was performed by the Stanford/NASA Center for Turbulence Research. Previous experimental data on back step flows were conducted at Reynolds numbers and/or expansion ratios which were significantly different from that of the DNS. The geometry of the experiment and the simulation were duplicated precisely, in an effort to perform a rigorous validation of the DNS. The Reynolds number used in the DNS was Re(sub h)=5100 based on step height, h. This was the maximum possible Reynolds number that could be economically simulated. The boundary layer thickness, d, was approximately 1.0 h in the simulation and the expansion ratio was 1.2. The Reynolds number based on the momentum thickness, Re(sub theta), upstream of the step was 610. All of these parameters were matched experimentally. Experimental results are presented in the form of tables, graphs and a floppy disk (for easy access to the data). An LDV instrument was used to measure mean velocity components and three Reynolds stresses components. In addition, surface pressure and skin friction coefficients were measured. LDV measurements were acquired in a measuring domain which included the recirculating flow region

Monitoring and characterization of bacterial populations of two biological air filters during the start up phase

[Abstract] This study aimed to monitor and characterize bacterial populations of two biological air filters during their start up phase (four months). The main objective of this work was to assess the potentiality of a microbiological approach to better understand the evolution of the bacterial populations within biofilters and therefore help to select biomass carrier media. The two biological filters were operated at full-scale (480 m3), filled with organic materials and dedicated to the removal of ammonia and Volatile Organic Compounds (VOCs). The first step of the work consisted in developing an extraction method for the biomass fixed on the solid supports. The second step investigated biofilters’ microbial ecology using molecular tools: DAPI (4,6-DiAmino-2- PhenylIndole), TVC (Total Viable Counts), FISH (Fluorescent In Situ Hybridization) and SSCP (Single Strand Conformation Polymorphism). The findings of the experiments did not show a significant evolution of total bacterial concentrations in biofilms of both biological filters during their start up phase. However, SSCP data analysis underlined important variations in the composition of bacterial populations. Finally, examination of the results highlighted the interest to inoculate organic media in order to reduce the acclimation time of microbial populations

Message Latency Characterization of a Distributed Live, Virtual, Constructive Simulation Environment

A distributed test environment incorporating Live, Virtual, Constructive, (LVC) concepts was developed to execute standalone and integrated simulations and flight-tests that support unmanned aircraft research for NASAs Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS) Project. The LVC components form the core infrastructure that supports simulation of UAS operations by integrating live and virtual aircraft in a realistic air traffic environment. This LVC infrastructure enables efficient testing by leveraging the use of existing distributed assets. The LVC concepts used for the UAS in the NAS project include live aircraft, flight simulators, and virtual air traffic control assets operating at facilities distributed across multiple NASA Centers. With a distributed network, however, there is a concern that message latency could impact the realism of a simulation and its data. The latencies associated with sending data among these distributed facilities were, therefore, measured to ensure that they fall within acceptable parameters. Several live and virtual test assets were integrated into the LVC infrastructure including NASA Armstrongs Ikhana MQ-9 unmanned aircraft, NASA Glenns S3-B manned aircraft, and the B747 flight simulator at NASA Ames. Average latencies from 100 to 150 milliseconds were observed between the LVC System running at NASA Ames and each of the participating NASA Centers under a light-to-moderate (fifty aircraft) traffic sample

Observation of surface states on heavily indium doped SnTe(111), a superconducting topological crystalline insulator

The topological crystalline insulator tin telluride is known to host superconductivity when doped with indium (Sn$_{1-x}$In$_{x}$Te), and for low indium contents ($x=0.04$) it is known that the topological surface states are preserved. Here we present the growth, characterization and angle resolved photoemission spectroscopy analysis of samples with much heavier In doping (up to $x\approx0.4$), a regime where the superconducting temperature is increased nearly fourfold. We demonstrate that despite strong p-type doping, Dirac-like surface states persist

Water adsorption on vanadium oxide thin films in ambient relative humidity.

In this work, ambient pressure x-ray photoelectron spectroscopy (APXPS) is used to study the initial stages of water adsorption on vanadium oxide surfaces. V 2p, O 1s, C 1s, and valence band XPS spectra were collected as a function of relative humidity in a series of isotherm and isobar experiments. Experiments were carried out on two VO2 thin films on TiO2 (100) substrates, prepared with different surface cleaning procedures. Hydroxyl and molecular water surface species were identified, with up to 0.5 ML hydroxide present at the minimum relative humidity, and a consistent molecular water adsorption onset occurring around 0.01% relative humidity. The work function was found to increase with increasing relative humidity, suggesting that surface water and hydroxyl species are oriented with the hydrogen atoms directed away from the surface. Changes in the valence band were also observed as a function of relative humidity. The results were similar to those observed in APXPS experiments on other transition metal oxide surfaces, suggesting that H2O-OH and H2O-H2O surface complex formation plays an important role in the oxide wetting process and water dissociation. Compared to polycrystalline vanadium metal, these vanadium oxide films generate less hydroxide and appear to be more favorable for molecular water adsorption

Candidate Bioinks for Extrusion 3D Bioprinting—A Systematic Review of the Literature

PurposeOur aim was to identify biomaterials that have been found to be suitable for extrusion 3D bioprinting, outline their biomechanical properties and biocompatibility towards their application for bioprinting specific tissue types. This systematic review provides an in depth overview of current biomaterials suitable for extrusion to aid bioink selection for specific research purposes and facilitate design of novel tailored bioinks

Ru layers electrodeposited onto highly stable Ti2AlC substrates as cathodes for hydrogen evolution in sulfuric acid solutions

In this work, the hydrogen evolution reaction (HER) was studied on Ru coated Ti2AlC electrodes in 1.0 mol dm(-3) H2SO4 at 25 degrees C. Ti2AlC was found to be a highly stable substrate in sulfuric acid solutions due to the formation of a passivating oxide layer on the surface, which was confirmed by the X-ray photoelectron spectroscopy (XPS) analysis of as-prepared and anodically treated Ti2AlC samples. Ru films were electrodeposited onto Ti2AlC substrates by cycling the potential of Ti2AlC in the solution containing 0.01 mol dm(-3) RuCl3 + 0.1 mol dm(-3) H2SO4 between -0.5 V and 0.4 V vs. a saturated calomel electrode (SCE) at the sweep rate of 20 mV s(-1). Four Ru/Ti2AlC samples were prepared, obtained at 5, 10, 15 and 20 cycles of Ru electrodeposition. Characterization of samples was performed by scanning electron microscopy (SEM) and cyclic voltammetry (CV), while the thickness of the electrodeposited Ru layers was determined by atomic force microscopy (AFM). It was found that the most compact sample with the thickness of about 0.42 mu m was obtained after 5 cycles. Electrochemical impedance spectroscopy (EIS) and steady-state polarization measurements showed that all Ru/Ti2AlC electrodes were exceptionally active for the HER. A Tafel slope of about -60 mV dec(-1) was observed on all polarization curves in the range of high cathodic current densities. Based on formal kinetics analysis, an appropriate mechanism for the HER on Ru/Ti2AlC was suggested.This is the peer-reviewed version of the article: Jovic, B. M., Jović, V. D., Lačnjevac, U., Stevanović, S., Kovac, J., Radovic, M.,& Krstajić, N. V. (2016). Ru layers electrodeposited onto highly stable Ti2AlC substrates as cathodes for hydrogen evolution in sulfuric acid solutions. Journal of Electroanalytical Chemistry, Elsevier, 766, 78-86. [https://doi.org/10.1016/j.jelechem.2016.01.038]The published version: [https://cer.ihtm.bg.ac.rs/handle/123456789/2012