Fabrication of infrared linear arrays of InAs planar avalanche photodiodes.

We report a, to the best of our knowledge, new device fabrication process for 128-pixel linear arrays of InAs planar avalanche photodiodes, utilizing selective area implantation of Beryllium ions into epitaxially-grown InAs wafers. The pixels exhibited uniform avalanche gain and responsivity. Room temperature responsivity values at 1550 and 2004 nm wavelengths are 0.49 ± 0.017 and 0.89 ± 0.024 A/W, respectively. Reverse dark current-voltage and avalanche gain measurements were carried out at different temperatures (from room temperature to 150 K). At 200 K at -15 V reverse bias, the pixels exhibited an avalanche gain of 22.5 ± 1.18 and dark current density of 0.68 ± 0.48 A/cm2.

Intravesical aminophylline instillation as an alternative for balloon dilatation prior to semi-rigid ureteroscopic management of distal ureteral stones.

PURPOSE: In a randomized controlled trial, we evaluated the effect of intravesical aminophylline instillation (IVAI) on intraureteral pressure of lower ureter and its use as an alternative to balloon dilatation after failure of advancing semi-rigid ureteroscope through the ureteric orifice without endodilatation. METHODS: Our study included 83 patients with juxta-vesical distal ureteral calculi requiring endodilatation after unsuccessfully introducing the semi-rigid ureteroscope through the ureteric orifice. Patients were randomized into two groups: group A (study group) included 41 patients, where IVAI was used to dilate the ureter and facilitate ureteroscopy (the intraureteral pressure was measured using a pressure transducer connected to an invasive pressure monitor before and 5 min after IVAI), whereas group B (control group) included 42 patients, where balloon dilatation was used prior to ureteroscopy. Perioperative surgical outcomes of ureteroscopy were evaluated in both groups. RESULTS: A statistically significant decrease in mean intraureteral pressure of intravesical ureter was found after IVAI from 12.34 mmHg ± 1.94 before injection to 8.46 mmHg ± 1.94 after injection (P < 0.001). Ureteral injuries, postoperative pain and hematuria were statistically significantly less among the study group compared to the control group (P < 0.05). We did not find statistically significant differences in operative time, need for DJ ureteral stenting or stone-free rate between both groups and no perioperative side effects were associated with IVAI. CONCLUSION: In ureteroscopic management of distal ureteral stones, intravesical aminophylline instillation is safe, inexpensive and effective in reducing intraureteral pressure and achieves comparable outcomes to balloon dilatation with less ureteral injuries, postoperative pain and hematuria.

A tactical multi-week implicit tour scheduling model with applications in healthcare.

In many healthcare tactical scheduling analyses, we need to solve large tour scheduling problems in which required staffing levels vary by time of day and day of week. A tour is a set of shift start times and shift lengths worked over a scheduling horizon of one or more weeks. As the degree of scheduling flexibility increases, the resulting tour scheduling problems get larger and this increase in size is exacerbated when the scheduling horizon is longer than one week. In this article, we present a tactical multi-week implicit tour scheduling model intended to complement operational scheduling systems. The implicit nature of the model allows us to solve problems that would be prohibitively large if modeled using traditional explicit tour scheduling approaches. We incorporate a variety of tour types with both intra-tour start time and shift length flexibility as well as varying degrees of weekend flexibility. We test the performance of our models on a set of medical units with different demand patterns. Computational experiments have shown that the developed implicit model can play an important role in quantifying trade-offs between labor costs, understaffing levels and scheduling flexibility. Our models have been released as an open source project in the hopes of facilitating practitioner use and also providing access to other scheduling researchers.

Surface modified of polyacrylonitrile nanofibers by TiO2/MWCNT for photodegradation of organic dyes and pharmaceutical drugs under visible light irradiation.

This work describes the fabrication of two composite nanofibers systems containing polyacrylonitrile polymer (PAN), Multiwall carbon nanotubes (MWCNT) and Titania (TiO2) nanoparticles. Photodegradation experiments were performed to study the effect of various parameters including pH, catalyst dose, pollutant concentration and reaction time for three model compounds, methylene blue (MB), indigo carmine (IC), and ibuprofen (IBU) under visible light. Morphology and structure of the modified composite nanofibers were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Thermogravimetric analysis (TGA), Photoluminescence (PL) spectroscopy, Raman spectra, and X-ray Photoelectron Spectra (XPS) analyses. The photocatalytic performance was achieved in a rather short time visible light (<30 min) and under low power intensity (125 W) compared to earlier reports. Kinetics data fitted well using pseudo-first order model to describe the mechanism of photocatalytic degradation processes. The stability and flexibility of the fabricated composite nanofibers allow their application in a continuous flow system and their re-use after several cycles.

Composite nanofibers for highly efficient photocatalytic degradation of organic dyes from contaminated water.

In this study highly efficient photocatalyst based on composite nanofibers containing polyacrylonitrile (PAN), carbon nanotubes (CNT), and surface functionalized TiO2 nanoparticles was developed. The composite nanofibers were fabricated using electrospinning technique followed by chemical crosslinking. The surface modification and morphology changes of the fabricated composite nanofibers were examined through SEM, TEM, and FTIR analysis. The photocatalytic performance of the composite nanofibers for the degradation of model molecules, methylene blue and indigo carmine, under UV irradiation in aqueous solutions was investigated. The results demonstrated that high photodegradation efficiency was obtained in a short time and at low power intensity compared to other reported studies. The effective factors on the degradation of the dyes, such as the amount of catalyst, solution pH and irradiation time were investigated. The experimental kinetic data were fitted using pseudo-first order model. The effect of the composite nanofibers as individual components on the degradation efficiency of MB and IC was evaluated in order to understand the overall photodegradation mechanism. The results obtained showed that all the components possess significant effect on the photodegradation activity of the composite nanofibers. The stability studies demonstrated that the photodegradation efficiency can remain constant at the level of 99% after five consecutive cycles.

Case management of childhood tuberculosis in children's hospitals in Khartoum.

No published information is available on the case management of childhood tuberculosis (TB) in Sudan. The aim of this study was to describe the case management of childhood TB in 4 children's hospitals in Khartoum State, Sudan. Data on 467 children aged 0-14 years registered in 2009 were collected from patient records; 52.9% males and 53.0% aged 5-14 years. Most cases were registered as new cases (89.5%) and most had pulmonary TB (72.4%). Of all cases, 31.0% had sputum smear microscopy done, 35.8% had X-ray and none had a record of being culture confirmed. Category III regimen was given to 58.5%. Reported outcomes were: cured (1.5%), completed treatment (14.6%), transferred out (13.1%), default (17.3%), death (4.3%) and treatment failure (0.6%). Age was significantly associated with treatment outcome, while sex, type of patient, site of TB and treatment category were not significant. Case management of childhood TB is suboptimal in this region.

Reservoir displacement by an invasive rodent reduces Lassa virus zoonotic spillover risk.

The black rat (Rattus rattus) is a globally invasive species that has been widely introduced across Africa. Within its invasive range in West Africa, R. rattus may compete with the native rodent Mastomys natalensis, the primary reservoir host of Lassa virus, a zoonotic pathogen that kills thousands annually. Here, we use rodent trapping data from Sierra Leone and Guinea to show that R. rattus presence reduces M. natalensis density within the human dwellings where Lassa virus exposure is most likely to occur. Further, we integrate infection data from M. natalensis to demonstrate that Lassa virus zoonotic spillover risk is lower at sites with R. rattus. While non-native species can have numerous negative effects on ecosystems, our results suggest that R. rattus invasion has the indirect benefit of decreasing zoonotic spillover of an endemic pathogen, with important implications for invasive species control across West Africa.

Comparative Study on the Effect of Phenolics and Their Antioxidant Potential of Freeze-Dried Australian Beach-Cast Seaweed Species upon Different Extraction Methodologies.

Brown seaweed is rich in phenolic compounds and has established health benefits. However, the phenolics present in Australian beach-cast seaweed are still unclear. This study investigated the effect of ultrasonication and conventional methodologies using four different solvents on free and bound phenolics of freeze-dried brown seaweed species obtained from the southeast Australian shoreline. The phenolic content and their antioxidant potential were determined using in vitro assays followed by identification and characterization by LC-ESI-QTOF-MS/MS and quantified by HPLC-PDA. The Cystophora sp. displayed high total phenolic content (TPC) and phlorotannin content (FDA) when extracted using 70% ethanol (ultrasonication method). Cystophora sp., also exhibited strong antioxidant potential in various assays, such as DPPH, ABTS, and FRAP in 70% acetone through ultrasonication. TAC is highly correlated to FRAP, ABTS, and RPA (p < 0.05) in both extraction methodologies. LC-ESI-QTOF-MS/MS analysis identified 94 and 104 compounds in ultrasound and conventional methodologies, respectively. HPLC-PDA quantification showed phenolic acids to be higher for samples extracted using the ultrasonication methodology. Our findings could facilitate the development of nutraceuticals, pharmaceuticals, and functional foods from beach-cast seaweed.

Identifying the genetic basis of viral spillover using Lassa virus as a test case.

The rate at which zoonotic viruses spill over into the human population varies significantly over space and time. Remarkably, we do not yet know how much of this variation is attributable to genetic variation within viral populations. This gap in understanding arises because we lack methods of genetic analysis that can be easily applied to zoonotic viruses, where the number of available viral sequences is often limited, and opportunistic sampling introduces significant population stratification. Here, we explore the feasibility of using patterns of shared ancestry to correct for population stratification, enabling genome-wide association methods to identify genetic substitutions associated with spillover into the human population. Using a combination of phylogenetically structured simulations and Lassa virus sequences collected from humans and rodents in Sierra Leone, we demonstrate that existing methods do not fully correct for stratification, leading to elevated error rates. We also demonstrate, however, that the Type I error rate can be substantially reduced by confining the analysis to a less-stratified region of the phylogeny, even in an already-small dataset. Using this method, we detect two candidate single-nucleotide polymorphisms associated with spillover in the Lassa virus polymerase gene and provide generalized recommendations for the collection and analysis of zoonotic viruses.

Static compressive tracking.

This paper presents the Static Computational Optical Undersampled Tracker (SCOUT), an architecture for compressive motion tracking systems. The architecture uses compressive sensing techniques to track moving targets at significantly higher resolution than the detector array, allowing for low cost, low weight design and a significant reduction in data storage and bandwidth requirements. Using two amplitude masks and a standard focal plane array, the system captures many projections simultaneously, avoiding the need for time-sequential measurements of a single scene. Scenes with few moving targets on static backgrounds have frame differences that can be reconstructed using sparse signal reconstruction techniques in order to track moving targets. Simulations demonstrate theoretical performance and help to inform the choice of design parameters. We use the coherence parameter of the system matrix as an efficient predictor of reconstruction error to avoid performing computationally intensive reconstructions over the entire design space. An experimental SCOUT system demonstrates excellent reconstruction performance with 16X compression tracking movers on scenes with zero and nonzero backgrounds.

Genome Sequences of Five Arenaviruses from Pygmy Mice (Mus minutoides) in Sierra Leone.

The genome sequences of five strains of a mammarenavirus were assembled from metagenomic data from pygmy mice (Mus minutoides) captured in Sierra Leone. The nearest fully sequenced relatives of this virus, which was named Seli virus, are lymphocytic choriomeningitis virus, Lunk virus, and Ryukyu virus.

Challenges, constraints and failures that are related to the posterior sagittal anorectoplasty approach to anorectal malformations in a low-resource context: An experience from a sudanese tertiary referral centre.

BACKGROUND: Anorectal malformations (ARMs) in the sub-Saharan Africa are a common cause of neonatal referral for intestinal obstruction, and the posterior sagittal anorectoplasty (PSARP) approach is rapidly spreading. The small number of paediatric surgeons and the low-resource context limit children's access to care and constrain the quality of results. A retrospective, observational study has been done on a consecutive series of ARM cases admitted to a Sudanese tertiary paediatric surgical centre within the framework of a partnership between Italian and Sudanese academic institutions addressed to review and upgrade the standard of care of major congenital anomalies. MATERIALS AND METHODS: The authors collected 94 ARM cases in a 3 years' period. Conditions on referral, operative procedures, post-operative course and follow-up were recorded and examined. Their correlations with complications and outcome were analysed. RESULTS: The male/female ratio was 47/47. Eighty patients presented with an untreated ARM; 66 had a divided stoma and 14 had already a PSARP procedure, followed by a poor outcome or sequelae. In 25% of the cases, colostomy required re-doing. In 57 cases, a staged PSARP (primary or re-do) was done. Surgical-site infections occurred in nine patients. Some patients were lost to follow-up after preliminary colostomy. Post-operative dilatation programme suffered from the lack of systematic follow-up, and colostomy closure was possible in 46% of the cases due to problems in travelling and accessing hospital care. Anal stenosis was frequently observed among unfollowed patients. CONCLUSION: Despite PSARP's widespread adoption in Africa, the risk of complications and failures is high. Primary management is often inappropriate, and a high rate of colostomy-related complications is observed. Poverty and lack of transportation reduce attendance to follow-up, hampering the final results. Investments in healthcare facilities and retention of trained health providers are needed to improve the standard of care.

Improving standard of pediatric surgical care in a low resource setting: the key role of academic partnership.

BACKGROUND: An epidemiological transition is interesting Sub-Saharan Africa increasing the burden of non-communicable diseases most of which are of surgical interest. Local resources are far from meeting needs and, considering that 50% of the population is less than 14 years of age, Pediatric surgical coverage is specially affected. Efforts are made to improve standards of care and to increase the number of Pediatric surgeons through short-term specialist surgical Missions, facilities supported by humanitarian organization, academic Partnership, training abroad of local surgeons. This study is a half term report about three-years Partnership between the University of Chieti- Pescara, Italy and the University of Gezira, Sudan to upgrade standard of care at the Gezira National Centre for Pediatric Surgery (GNCPS) of Wad Medani. Four surgical Teams per year visited GNCPS. The Program was financed by the Italian Agency for Development Cooperation. METHODS: The state of local infrastructure, current standard of care, analysis of caseload, surgical activity and results are reported. Methods utilized to assess local needs and to develop Partnership activities are described. RESULTS: Main surgical task of the visiting Team were advancements in Colorectal procedures, Epispadias/Exstrophy Complex management and Hypospadias surgery (20% of major surgical procedures at the GNCPS). Intensive care facilities and staff to assist more complex cases (i.e. neonates) are still defective. Proctoring, training on the job of junior surgeons, anaesthetists and nurses, collaboration in educational programs, advisorship in hospital management, clinical governance, maintenance of infrastructure together with training opportunities in Italy were included by the Program. Despite on-going efforts, actions have not yet been followed by the expected results. More investments are needed on Healthcare infrastructures to increase health workers motivation and prevent brain drain. CONCLUSIONS: The key role that an Academic Partnership can play, acting through expatriated Teams working in the same constrained contest with the local workforce, must be emphasized. Besides clinical objectives, these types of Global Health Initiatives address improvement in management and clinical governance. The main obstacles to upgrade standard of care and level of surgery met by the Visiting Team are scarce investments on health infrastructure and a weak staff retention policy, reflecting in poor motivation and low performance.

Removal of hexavalent chromium by electrospun PAN/GO decorated ZnO.

A novel composite nanofibers material have fabricated by using electrospinning technique followed by chemical cross-linking with zinc oxide (ZnO). The surface sensitization and morphology changes of the fabricated composite nanofibers were studied by using X-Ray Diffraction (XRD) analysis, Scanning Electron Microscopy (SEM) and transmission electron microscope (TEM). The effect of operating parameters includes the amount of ZnO, initial solution PH, and hexavalent chromium concentration on adsorption were investigated. The maximum adsorption capacity was found to be 690 mg/g at pH 6, which is much higher than most of the reported adsorbents. The adsorption equilibrium reached within 25 and 180 min as the initial solution concentration increased from 10 to 300 mg/L, and the data fitted well using nonlinear pseudo first order model with determination coefficient (R2) in between 0.97 and 0.99. Adsorption isotherms correlate the data on equilibrium adsorption with different mathematical models to describe the behaviour of an adsorption process and provide valuable information for optimizing the design of an adsorption system.

High performance of PAN/GO-ZnO composite nanofibers for photocatalytic degradation under visible irradiation.

In this work, Polyacrylonitrile nanofibers were enhanced by graphene oxide and zinc oxide, in terms of enhanced the photocatalytic activity and mechanical properties for the composite nanofibers. Photocatalytic degradation of two organic dyes methylene blue dye and indigo carmine dye from the simulated industrial wastewaters has been investigated under visible light irradiation. Composite nanofibers fabricated by using electrospinning technique followed by chemical cross-linking with zinc oxide. The surface sensitization and morphology changes of the fabricated composite nanofibers were studied using Fourier transform infrared spectroscopy analysis, Scanning Electron Microscopy and transmission electron microscope. Sensitized zinc oxide with graphene oxide showed higher efficiency in the degradation of MB with a 96% of degradation efficiency after 70 min and 98% for IC after merely 27 min. The optimum catalytic parameters such as initial organic dye concentration and pH were discussed. The efficacy of degradation of methylene blue dye and indigo carmine increased as initial concentration decreased. The optimal pH was around 5 where the reaction rate decreases above and under this pH value.

BLT2 is expressed in PanINs, IPMNs, pancreatic cancer and stimulates tumour cell proliferation.

Pancreatic cancer has an abysmal prognosis. Targets for early detection, prevention and therapy are desperately needed. Inflammatory pathways have an important impact on tumour growth and progression. Expression of BLT2 (the second leukotriene B(4) receptor) was investigated by real-time RT-PCR and immunohistochemistry. Cell proliferation was studied after stable transfection with BLT2, after treatment with siRNA and Compound A as an agonist. BLT2 is expressed in all pancreatic cancer cell lines. Results from real-time RT-PCR revealed significant overexpression of BLT2 in malignant intraductal papillary mucinous neoplasias (IPMNs) and pancreatic adenocarcinoma. Intense staining was evident in IPMNs, infiltrating tumour cells and advanced pancreatic intraepithelial neoplasias (PanINs) but not in normal ductal cells. Overexpression of BLT2 as well as stimulation of Colo357, Panc-1 and AsPC1 cells with Compound A caused a significant increase in tumour cell proliferation, an effect reversed after siRNA treatment. This study demonstrates for the first time the expression of BLT2 in the pancreas and overexpression in pancreatic cancers and malignant IPMNs in particular. Upregulation of BLT2 is already evident in precursor lesions (PanINs, IPMNs). Overexpression of this receptor leads to significant growth stimulation. Therefore, we suggest BLT2 as a new target for chemoprevention and therapy for pancreatic cancer.

Surface functionalized composite nanofibers for efficient removal of arsenic from aqueous solutions.

A novel composites nanofiber was synthesized based on PAN-CNT/TiO2-NH2 nanofibers using electrospinning technique followed by chemical modification of TiO2 NPs. PAN-CNT/TiO2-NH2 nanofiber were characterized by XRD, FTIR, SEM, and TEM. The effects of various experimental parameters such as initial concentration, contact time, and solution pH on As removal were investigated. The maximum adsorption capacity at pH 2 for As(III) and As(V) is 251 mg/g and 249 mg/g, respectively, which is much higher than most of the reported adsorbents. The adsorption equilibrium reached within 20 and 60 min as the initial solution concentration increased from 10 to 100 mg/L, and the data fitted well using the linear and nonlinear pseudo first and second order model. Isotherm data fitted well to the linear and nonlinear Langmuir, Freundlich, and Redlich-Peterson isotherm adsorption model. Desorption results showed that the adsorption capacity can remain up to 70% after 5 times usage. This work provides a simple and an efficient method for removing arsenic from aqueous solution.

Removal of chromium (VI) from aqueous solutions using surface modified composite nanofibers.

A novel material composite nanofibers (PAN-CNT/TiO2-NH2) based on adsorption of Cr(VI) ions, was applied. Polyacrylonitrile (PAN) and carbon nanotube (CNTs)/titanium dioxide nanoparticles (TiO2) functionalized with amine groups (TiO2-NH2) composite nanofibers have been fabricated by electrospinning. The nanostructures and the formation process mechanism of the obtained PAN-CNT/TiO2-NH2 composite nanofibers are investigated using FTIR, XRD, XPS, SEM, and TEM. The composite nanofibers were used as a novel adsorbent for removing toxic chromium Cr(VI) in aqueous solution. The kinetic study, adsorption isotherm, pH effect, initial concentration, and thermodynamic study were investigated in batch experiments. The composite nanofibers had a positive effect on the absorption of Cr(VI) ions under neutral and acidic conditions, and the saturated adsorption reached the highest when pH was 2. The adsorption equilibrium reached within 30 and 180min with an initial solution concentration increasing from 10 to 300mg/L, and the process can be better described using nonlinear pseudo first than nonlinear pseudo second order model and Intra-particle diffusion. Isotherm data fitted well using linear and nonlinear Langmuir, Freundlich, Redlich-Peterson, and Temkin isotherm adsorption model. Thermodynamic study showed that the adsorption process is exothermic. The adsorption capacity can remain up to 80% after 5 times usage, which show good durability performance. The adsorption mechanism was also studied by UV-vis and XPS.

Effects of nicotine on homeostatic and hedonic components of food intake.

Chronic tobacco use leads to nicotine addiction that is characterized by exaggerated urges to use the drug despite the accompanying negative health and socioeconomic burdens. Interestingly, nicotine users are found to be leaner than the general population. Review of the existing literature revealed that nicotine affects energy homeostasis and food consumption via altering the activity of neurons containing orexigenic and anorexigenic peptides in the brain. Hypothalamus is one of the critical brain areas that regulates energy balance via the action of these neuropeptides. The equilibrium between these two groups of peptides can be shifted by nicotine leading to decreased food intake and weight loss. The aim of this article is to review the existing literature on the effect of nicotine on food intake and energy homeostasis and report on the changes that nicotine brings about in the level of these peptides and their receptors that may explain changes in food intake and body weight induced by nicotine. Furthermore, we review the effect of nicotine on the hedonic aspect of food intake. Finally, we discuss the involvement of different subtypes of nicotinic acetylcholine receptors in the regulatory action of nicotine on food intake and energy homeostasis.

Carotid patch and cerebrovascular event relation after carotid endarterectomy procedure.

BACKGROUND: Carotid endarterectomy (CEA) is the treatment of choice for patients with symptomatic and asymptomatic high-grade carotid stenosis. In literature there are papers advocating patch plasty for better results. But there is controversy about which patch material is optimal for use. This study compared rate of neurologic events, and perioperative death in patients undergoing CEA with primary closure versus patch closure. METHODS: We compared patch angioplasty to primary closure between August 2008 and December 2012 in 57 operations. Patients grouped according to their closure technique. Early (30-day) stroke and mortality rate were evaluated. Mean age of patients was 67.79±10.19 (range 41-85 years). 15 (26.31%) of patients were female. RESULTS: Primary closure was used in 13 operations, and patch angioplasty was used in 44 (saphenous vein: 5, Dacron: 23, Fabric: 5, Carotid: 11). There were no significant differences among groups' baseline characteristics. Primary closure was associated with significantly more postoperative major stroke compared with patch used closure (P=0.05). None of preoperative variables were associated with postoperative stroke. CONCLUSIONS: On the basis of our results, avoiding primary closure for CEA is defendable. But choice of patch material needs large trials to conclude.