Fabrication of an ultra-sensitive para-nitrophenol sensor based on facile Zn-doped Er2O3 nanocomposites via an electrochemical approach.

In this study, a semiconductor-doped nanocomposite material (Zn-doped Er2O3 nano-composites) was prepared via a single-step wet-chemical technique at alkaline pH. Fourier-transform infrared spectroscopy (FT-IR), UV/Vis spectroscopy, photoluminescence spectroscopy (PL), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (XEDS), and X-ray powder diffractometry (XRD) were applied to determine the structural and morphological properties of the Zn-doped Er2O3 nanocomposite. A thin layer of aggregated Zn-doped Er2O3 nanocomposite was fabricated on the flat surface of a glassy carbon electrode (GCE) with 5% ethanolic Nafion as conducting coating binder for the development of a selective and sensitive p-nitrophenol (para-NP) capturing electrochemical probe for environmental remediation. After the fabrication of the sensor, a novel current-potential (I-V) electrochemical approach was applied to determine its selectivity and sensitivity together with all the necessary analytical parameters against para-NP. Moreover, the calibration plot was found to be linear with the linear dynamic range (LDR) of para-NP concentration. The limit of detection (LOD) at a signal-to-noise ratio of 3 (S/N ∼ 3) and sensitivity were also calculated to be 0.033 ± 0.002 pM and 28.481 × 10-2 µA µM-1 cm-2, respectively, based on the gradient of the calibration plot, and the limit of quantification (LOQ) was determined to be 0.11 ± 0.02 pM. This work demonstrates a well-known approach for the first time that can be used for the development of efficient electrochemical sensors. These sensors based on semiconductor doped nanomaterials embedded onto the GCE for the detection of toxic chemicals in an aqueous system as an environmental remediation. It can be further applied for the analysis of real environmental samples and in the healthcare field.

Perinatal Complications in Diabetes Mellitus with Pregnancy: Comparison between Gestational Diabetes Mellitus (GDM) and Diabetes Mellitus Prior to Pregnancy.

Diabetes is alarmingly high among Bangladeshi people. But there have been very few studies assessing the effect of diabetes on perinatal outcomes, particularly comparing diabetes prior to pregnancy and gestational diabetes (GDM). This cross sectional observational study was conducted in the Department of Obstetrics & Gynaecology, BIRDEM Hospital, Dhaka, Bangladesh from September 2010 to February 2011. Pregnant women admitted in BIRDEM Hospital for delivery after 28 weeks of gestation were selected to assess perinatal complications of GDM and diabetes prior to pregnancy and to compare them after taking permission from institutional review board. Perinatal complications of 50 women with gestational diabetes, 50 pregnant women with diabetes prior to pregnancy, and 50 non diabetic pregnant women as control were studied after taking written consent and the outcomes between GDM, and mother with diabetes prior to pregnancy were compared. Perinatal outcomes including congenital anomalies, birth asphyxia, macrosomia, respiratory distress syndrome (RDS), hypoglycemia, hyperbilirubinaemia, and perinatal mortality were compared. Neonatal complications were significantly higher in both pregnancy with prior diabetes (74%) and gestational diabetes (58%) when compared with non diabetic control (24%). Leading neonatal complications were macrosomia, birth asphyxia, hyperbilirubinaemia, and hypoglycemia. Macrosomia was significantly higher in GDM than non diabetic group (10% vs. 0%, p=0.003). Frequency of birth asphyxia, hyperbilirubinaemia, and hypoglycemia were significantly higher in the infant of mother with prior diabetes (22%, 54%, & 22% respectively) and GDM (20%, 38%, 18% respectively) than that of non diabetic mother (6%, 20%, 0% respectively). Compared to GDM, mother with prior diabetes had more frequent hyperbilirubinaemia (38% vs. 54%, p=0.004) and hypoglycemia (18% vs. 22%, p=0.04). Women with diabetes had worse pregnancy outcomes compared to non-diabetic mothers. Pregnancy prior to diabetes is associated with more frequent complications than gestational diabetes.

Optimisation of the batch reactor for the removal of cobalt ions from chloride media.

A series of experiments were carried out to determine the best medium for the recovery of cobalt by means of an electrogenerative system. Use of the electrogenerative system with a chloride medium had shown promising performance with the highest free energy of -389.8 kJ mol(-1) compared to that with sulphate and nitrate media. Subsequently, the influence of catholyte concentrations on cobalt recovery using the electrogenerative process was carried out by varying the initial cobalt concentration and sodium chloride concentration. The results showed that almost 100% recovery was attained within 1-4 h of the recovery process. Influence of pH was investigated where the electrogenerative system performed best between pH 5.0 and 7.0. Maximum cell performance of 83% with 99% cobalt removal was obtained at 90 min when 100 mg L(-1) of Co(2+) in 0.5 M NaCl was taken as catholyte solution. The values of ΔH(o) and ΔS(o) of the process were evaluated as 33.41 kJ mol(-1) and 0.13 kJ mol(-1), respectively.

Tuberculous pleural effusion.

Despite prevention programs, tuberculosis is still endemic in developing countries. Extrapulmonary tuberculosis is increasing globally in the face of recent emergence of Human Immunodeficiency Virus (HIV) infection. Pleural tuberculosis is a common problem in daily clinical practice. We assessed 26 cases of tuberculous pleural effusion admitted in Bangabandhu Sheikh Mujib Medical University from 2002 to 2007. The diagnosis was based upon clinical examination, tuberculin reaction, imaging, pleural fluid analysis and response to antitubercular chemotherapy a surrogate clinical determinant. Apparently promising newer biochemical pleural fluid measurements were not utilized due to a number of limitations. The presenting symptoms found in this prospective analysis are fever (100%), nonproductive cough (73%), pleuritic chest pain (38%), loss of weight (38%) and shortness of breath (38%). A high index of suspicion after confident exclusion of malignancy and pneumonia is a clue to diagnosis. Out of 80 cases of extrapulmonary tuberculosis admitted during the study period, tuberculous pleural effusion constitutes 32.50%.

Adsorption and photocatalytic decolorization of a synthetic dye erythrosine on anatase TiO2 and ZnO surfaces.

The UV radiation assisted photocatalytic decolorization/degradation kinetics of an anionic dye erythrosine (ER), has been studied over TiO2 and ZnO surfaces. Since adsorption is the prerequisite condition for decolorization/degradation of dye molecules in presence of heterogeneous catalysis, the Langmuir and Freundlich isotherms were examined to verify the adsorption intensity. Standard adsorption free energy measurement implies that the adsorption of ER on both TiO2 and ZnO surfaces is spontaneous endothermic process. The effect of catalyst loading (TiO2/ZnO) revealed the fact that the maximum decolorization rate is obtained under an optimized catalyst loading condition. The decolorization efficiency was also investigated over the pH range of 5.0-10.0 indicating that increasing pH enhances decolorization efficiency. The influence of H2O2 on decolorization efficiency was found noticeable since it is a hydroxyl radical provider. The kinetic study of this degradation indicates that under the experimental condition, the decolorization mechanism follows zero order kinetics on the basis of Langmuir-Hinshelwood (L-H) heterogeneous reaction mechanism.