No abstract

Crystallization and morphology of perovskite film played an important role to obtain efficient performance of perovskite solar cells. This study is aimed at optimizing the fabrication of hybrid organic–inorganic lead iodide perovskite layer by a two-step method modified by a double dip coating process which enables to control the perovskite crystallization and morphology. The duration time of each circle for the step of dipping PbI2 film to methylammonium iodide solution was varied from 90 to 240 second. The obtained perovskite films were characterized by X-ray diffraction to evaluate the transformation of PbI2 reactant to the perovskite product and its crystallization, by scanning electron microscopy to observe its morphology. Then, the perovskite films were implemented in functional perovskite solar cell devices followed by current–voltage characterization. Results showed that the perovskite was formed via an equilibrium process which reached an optimum transformation of PbI2 to the product after 2 × 150  second circle dip coating, and its morphology was smooth with the least voids. The solar cell devices fabricated at the optimum conditions achieved a comparable performance of about 14%.

Background: Dyslipidemia is highly prevalent in patients with chronic kidney disease (CKD), and the relationship between dyslipidemia and renal function in these patients remains controversial. Our objectives were to determine the triglycerides/HDL-cholesterol ratio (TG/HDL-C), evaluate the correlation between TG/HDL-C and the urine albumin/creatinine ratio (ACR), and estimate the glomerular filtration rate (eGFR) according to MDRD in CKD patients. Methods: A descriptive cross-sectional study was conducted on 152 patients with CKD at the Endocrine Clinic, the University of Medicine and Pharmacy Hospital, Ho Chi Minh City, Vietnam. Study subjects were medically examined and recorded information on the data collection form. Subjects were tested for total cholesterol, triglycerides, HDL-C, LDL-C, urea, creatinine and albumin, urine creatinine, and eGFR according to the MDRD formula. Data were analyzed using SPSS Statistics version 20.0. Results: The average age was 58.08 ± 15.69 years, and the overweight and obesity rate was 54%. Most patients had comorbidities, among which the most common diseases were hypertension and diabetes mellitus. Among the subjects, 57.3% were CKD stage 3 patients, and ACR was in the range of 30–300 mg/g. According to the classification of CKD using GFR and ACR categories, 40.8% of patients were at very high risk. The average TG/HDL-C ratio was 5.09 ± 4.26. There was a medium negative correlation between TG/HDL-C and eGFR (R = 0.44, p < 0.01) and a weak positive correlation between TG/HDL-C and ACR (R = 0.34, p < 0.01). Conclusions: The TG/HDL-C ratio was a risk factor associated with CKD and was noticeable in monitoring and assessing the risk of progression of CKD.

Influence of Al-concentration on structure, magnetic properties and magnetocaloric effect of ( and 8) rapidly quenched ribbons was investigated. X-ray diffraction analysis shows that the ribbons exhibit single phase with a -cubic structure. Curie temperature, , of the alloy is slightly increased with increasing Al-concentration. Specially, the sample with has both the first- (FOPT) and second- (SOPT) order magnetic phase transitions. The reason for the FOPT in the alloy ribbons is due to existence of the structural transformation between martensitic and austenitic phases. The alloy owns both the positive and negative magnetocaloric effects with maximum magnetic entropy changes of and (in magnetic field change ), respectively. By using Arrott-Noakes and Kouvel-Fisher methods, the critical parameters of the alloy were determined to be close to those of the mean field theory of long-range ferromagnetic orders.