Challenges of providing maintenance hemodialysis in a resource poor country: Experience from a single teaching hospital in Lagos,Southwest Nigeria

Providing maintenance hemodialysis is associated with high costs and poor outcomes. In Nigeria, more than 90% of the population lives below the poverty line, and patients with end‐stage renal disease (ESRD) pay out‐of‐pocket for maintenance hemodialysis. To highlight the challenges of providing maintenance hemodialysis for patients with ESRD in Nigeria, we reviewed records of all patients who joined the maintenance hemodialysis program of our dialysis unit over a 21‐month period. Information regarding frequency of hemodialysis, types of vascular access for dialysis, mode of anemia treatment and frequency of blood transfusion received were retrieved. One hundred and twenty patients joined the maintenance hemodialysis program of our unit during the period under review. Seventy‐two (60%) were males and the mean age of the study population was 47 + 14 years. The mean hemoglobin concentration at commencement of dialysis was 7.3 g/dL + 1.6 g/dL. The initial vascular access was femoral vein cannulation in all the patients. A total of 73.5% of the patients required blood transfusion at some point with 33% receiving five or more pints of blood. Only 3.3% of the patients had thrice weekly dialysis, 21.7% dialyzed twice weekly, 23.3% once weekly, 16.7% once in two weeks, 2.5% once in three weeks and 11.7% once monthly. At the time of review, 8.3% of the patients had died while 38.3% were lost to follow‐up. Majority of patients with ESRD on maintenance hemodialysis in our unit were poorly prepared for dialysis, were under‐dialyzed, and were frequently transfused with blood with resultant poor outcomes.     

A systematic review and meta-analysis of the effectiveness of biosecurity and vaccination in reducing Salmonella spp. in broiler chickens

Our objective was to estimate the effectiveness of vaccination and biosecurity on the prevalence of Salmonella spp. in broiler chickens using systematic review and meta-analysis. A comprehensive search of the global primary literature was conducted in: Current Contents (1999–2009), Agricola (1924–2009), MEDLINE (1860–2009), Scopus (1960–2009), CAB (1913–2009), and Centre for Agricultural Bioscience Global Health (1971–2009). The search algorithm was (Salmonell*) AND (chicken* OR chick* OR poultry* OR broiler* OR gallus*). Additional studies were identified by contacting five topic experts and hand-scanning bibliographies of recent review articles and a recently published textbook. Studies were included if they were English language and investigated the effects of vaccination and biosecurity on the prevalence of Salmonella spp. in broiler chickens. All study design types were included. Data extraction and methodological assessment were conducted by two reviewers independently. All meta-analyses were based on random-effects models. For biosecurity, sixteen challenge studies (n = 137 treatment-control comparisons) and one controlled study (n = 2) met the inclusion criteria. Significant heterogeneity (Cochran's Q-statistic, p < 0.001) was observed among biosecurity challenge studies examining hydrogen peroxide or polyhexamethylenebiguanide hydrochloride applied to hatching eggs, making it inappropriate to present a summary effects measure. For vaccination, 19 challenge studies (n = 226) and three controlled studies (n = 10) met the inclusion criteria. Among live Salmonella Typhimurium vaccine challenge studies heterogeneity was not significant (p = 0.138). Vaccination with a live Salmonella Typhimurium reduced the risk of Salmonella cecal colonization in the treated broiler group by 35 out of 1000 broilers when compared to the control group (OR = 0.21; 95% CI = 0.06–0.77) and this effect was significant (p = 0.018). One biosecurity study (n = 2 treatment-control comparisons) and three vaccination studies (n = 10) were conducted in a commercial setting. The two included studies in the vaccination meta-analysis were both conducted at research facilities. The live Salmonella Typhimurium vaccine showed the most promise in reducing the prevalence of Salmonella in broiler ceca. However, the meta-analysis included few studies, and these studies challenged the birds with different serotypes. We recommend that more large-scale randomized, blinded trials be conducted with a live Salmonella Typhimurium vaccine on commercial farms.     

Varying Heating Effect on Mixed Convection of Nanofluids in a Vented Horizontal Cavity with Injection or Suction

The problem of mixed convection heat transfer inside a horizontal vented enclosure through the lower and upper parts, respectively, of its left and right vertical walls is studied numerically using Al₂O₃-water nanofluid as working fluid. The bottom wall is subjected to a linearly varying (increasing or decreasing) heating temperature profiles, while the other boundaries are considered thermally insulated. The fresh fluid is admitted from the bottom part of the left vertical wall by injection or by the suction imposed on the opening of the right vertical wall. Based on numerical predictions, the conjugate effect of the Reynolds number and the nanoparticle concentration on fluid flow and heat transfer characteristics is studied. The obtained results demonstrate clearly the positive role of the nanoparticles addition on the improvement of the heat transfer rate and the mean temperature within the cavity. In addition, the flow structure and the temperature distribution inside the cavity are seen to be very sensitive to the variations of the Reynolds number, the imposed external flow mode, and the heating type. Results presented show that, in general, the decreasing heating mode is more favorable to the heat transfer in comparison with the case of the increasing heating mode. The cooling efficiency is found to be more pronounced by the injection/suction mode by applying the increasing/decreasing heating type.     

Effect of Process Parameters on Work Index, Milling Efficiency and Some Technological Properties of Yam Flour Using Attrition Mill

The effect of process parameters on work index, efficiency of milling, bulk density, swelling capacity and water absorption capacity of yam flour using attrition mill was studied. Independent variables were: moisture content (8, 12, 16, 20 and 24 % w.b.), speed (288, 346, 432, 576 and 864 rpm) and inlet opening (1,300, 2,600, 3,900, 5,200 and 6,500 mm²). The responses were work index, milling efficiency, bulk density, water absorption and swelling capacities of the flour. Work indexes for milling yam flour, meal and grit were found to be 0.25?±?0.13, 0.49?±?0.14 and 1.8?±?0.56, respectively. Flour fraction, bulk density, water absorption capacity and swelling capacity ranged from 42.2 to 56.6 %, 0.54 to 0.66 g/m³, 200 to 400 % and 13 to 23 ml, respectively. The treatments were found to influence the responses significantly (p?<?0.05). Optimum process condition was achieved at 12 % moisture content of feed, 506 rpm shaft speed and 5,200 mm² feed opening giving 19.1 % grit, 23.6 % meal and 54.2 % flour. The desirability of the optimisation process was 0.78. Validation of predicted optimal moisture content, worm shaft speed and feed inlet opening gave errors of 19, 14.4 and 6.1 % for grit, meal and flour, respectively.     

Positron-defect profiling in Cd<Subscript>1−x</Subscript>Zn<Subscript>x</Subscript>Te wafers after saw cutting

Near-surface damage induced by saw cutting of ingots of Cd_1−xZn_xTe was investigated by positron-defect depth profiling. The damage extends to several micrometers depth and depends on the cutting apparatus. The samples were polished and etched repeatedly, followed each time by positron-depth profiling. New subsurface damage created during the polishing process is observed. No new damage is observed after etching. Positron-depth profiling is suggested as a diagnostic tool to monitor the quality of sample surfaces.     

Improved DNA-repair parameters in PHA-stimulated peripheral blood lymphocytes of human subjects with low body mass index

Effects of spinal cord transection on the synaptology of zebrafish spinal motoneurons were studied. The transection was made at the level of the 14th vertebra and the synaptology of motoneuron somata and dendrites was analysed at the level of the 21st to the 23rd vertebrae at one month and three months after transection. Horseradish peroxidase, applied to the myotomal muscle, was used to label motoneuron somata and dendritic branches in central and in lateral areas of the neuropil (referred to as central and lateral dendritic profiles). Boutons impinging on motoneurons were classified according to the morphology of the vesicles. We discerned R-boutons with spherical vesicles, F-boutons with flat vesicles and DC-boutons with at least one dense core vesicle. The apposition lengths of R-, F- and DC-boutons and the circumference of labelled profiles were determined to assess the proportional covering of boutons on somata and dendrites. Ratio's of covering with R- and F-boutons (R/F ratio) for somata, central and lateral dendritic profiles were 1.1, 2.1, and 2.1 in control fish and 0.5, 0.5 and 0.9 in lesioned fish at one month after transection, respectively. The total covering of motoneurons in lesioned fish was decreased by 20% on somata and by 30% on lateral dendritic profiles, whereas central dendritic profiles did not change significantly. At three months after transection the R/F ratio's for somata, central and lateral dendritic profiles were 0.5, 0.7 and 0.6, respectively. The total covering on somata and central and lateral dendritic profiles was at control levels. The anatomical aspects of the changes in synaptology indicate that in control fish 50 to 60% of the R-boutons on the motoneuron surface originate from descending axons. In contrast, almost all F-boutons seem to be from local origin.     

Investigating the cause of excessive seepage in a dam foundation using seismic and electrical surveys—a case study of Asa Dam,West Africa

Bulletin of Engineering Geology and the Environment - A case study is reported in this paper, where a combination of seismic refraction and electrical resistivity surveys is used to investigate the...     

Novel fabrication of extremely high aspect ratio and straight nanogap and array nanogap electrodes

Microsystem Technologies - We reported a reproducible, simple and novel method for fabricating electrodes with high aspect ratio and highly straight nanometer size gap. The gap size could be...