Investigation of Thermal Stability Effects of Thick Hydrogenated Amorphous Silicon Precursor Layers for Liquid Phase Crystallized Silicon

The thermal stability of thick amp; 8776;4 amp; 8201; amp; 956;m plasma grown hydrogenated amorphous silicon a Si H layers on glass upon application of a rather rapid annealing step is investigated. Such films are of interest as precursor layers for laser liquid phase crystallized silicon solar cells. However, at least half day annealing at T amp; 8776;550 amp; 8201; C is considered to be necessary so far to reduce the hydrogen H content and thus avoid blistering and peeling during the crystallization process due to H. By varying the deposition conditions of a Si H, layers of rather different thermal stability are fabricated. Changes in the surface morphology of these a Si H layers are investigated using scanning electron microscopy and profilometry measurements. Hydrogen effusion, secondary ion mass spectrometry SIMS depth profiling, and Raman spectroscopy measurements are also carried out. In summary, amorphous silicon precursor layers are fabricated that can be heated within 30 amp; 8201;min to a temperature of 550 amp; 8201; C without peeling and major surface morphological changes. Successful laser liquid phase crystallization of such material is demonstrated. The physical nature of a Si H material stability instability upon application of rapid heating is studie

Erythropoietic response to anaemia of dialysis naïve patients with chronic kidney disease in Zaria, north west Nigeria

Introduction: Chronic kidney disease (CKD) is a global health problem with an increasing prevalence worldwide. Anemia is one of its consistent and severe hematological complications although its mechanism is not fully elucidated. The primary defect could manifest as serum erythropoietin (sEPO) deficiency or EPO resistance. We set out to determine the erythropoietic response to anemia of patients with CKD and its relationship with their iron status in a cross‑sectional descriptive study of 91 patients in various stages of CKD.Materials and Methods: Soluble transferrin receptor (sTfR), sEpo, and serum ferritin levels were determined using ELISA method (Diagnostic Automation Inc and WKEA med supplies corp.). Data generated were analyzed using Epi Info version 3.5.3 and level of statistical significance was set at ≤0.05.Results: Participants comprised of 50 females (54.9%) and 41 (45.1%) males with an overall mean age of 47 ± 15 years. The major causes of CKD were hypertension (HTN) (50.54%), diabetes mellitus (DM) (6.59%), and HTN + DM (19.78%). The mean hemoglobin (Hb) concentration of the participants was 10.97 ± 2.28 g/dl; the red cell indices were within normal ranges except for Red cell distribution width‑Coefficient of variation (%) which was elevated (16.29%). The mean serum ferritin, sTfR, and sEpo were 70.58 ± 46.44 ng/ml (interquartile range [IQR] 82.00), 22.9 ± 49.7 ng/ml (IQR 15.00), and 12.49 ± 33.47 IU/L (IQR 6.00), respectively, with a high variance. Serum ferritin and sTfR are consistentlylow across the stages of CKD (range between 54.54 ng/ml and 88.64 ng/ml), but sEPO for stage 3 and 4 showed a 2‑fold increase when compared to normal level at Hb 10.97 g/dl (29.54 IU/L and 38.83 IU/L, respectively). Correlation between sTfR and sEpo (r2 = 0.96, P = 0.001), while between sEpo and serum ferritin (r2 = 0.02, P = 0.185), and between Hb and stage of CKD undulating (r2 = 0.41, P = 0.001).Conclusion: In contrast to some existing literature, this study has demonstrated that EPO resistance and iron deficiency contributes to anemia in CKD and serumferritin can be used to assess the iron level of dialysis naïve CKD patients at every stage of the disease.Keywords: Chronic kidney disease, erythropoietin, serum erythropoietin, serum ferritin, serum transferrin recepto