Synthesis and Characterization of Cu2ZnSnSe4 by Non-Vacuum Method for Photovoltaic Applications.

Wet ball milling was used for the synthesis of Cu2ZnSnSe4 (CZTSe) nanoparticles with a kesterite structure. The prepared nanoparticles were used for ink formulation. Surfactants and binders were added to improve the ink stability, prevent agglomeration, and enhance ink adhesion. The films deposited via spin coating were annealed at different temperatures using a rapid thermal processing system in the presence of selenium powder in an inert environment. Analytical techniques, such as X-ray diffraction, Raman spectroscopy, and Fourier-transform infrared spectroscopy, were used to confirm the formation of CZTSe nanoparticles with a single-phase, crystalline kesterite structure. Field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to study the surface morphology and chemical composition of the thin films before and after annealing, with and without the sodium solution. The optoelectrical properties were investigated using ultraviolet-visible spectroscopy and Hall measurements. All the prepared CZTSe thin films exhibited a p-type nature with an optical bandgap in the range of 0.82-1.02 eV. The open-circuit voltage and fill factor of the CZTSe-based devices increased from 266 to 335 mV and from 37.79% to 44.19%, respectively, indicating a decrease in the number of recombination centers after Na incorporation.

Fabrication of Cu2ZnSnS4 Light Absorber Using a Cost-Effective Mechanochemical Method for Photovoltaic Applications.

In the present study, we adopt an easy and cost-effective route for preparing Cu2ZnSnS4 (CZTS)-absorber nanoparticles by a mechanochemical method using non-toxic and environmentally benign solvents (butanol, methyl ethyl ketone, and ethanol). The gram-scale synthesis of absorber nanoparticles was achieved in a non-hazardous, zero-waste process without using high-vacuum equipment. The effects of annealing and Na incorporation on the properties of spin-coated CZTS thin films were scrutinized. The deposited samples showed kesterite crystal structure and single phase. The morphological results revealed an improvement in the surface morphology after annealing. The optical bandgaps of the thin films lied in the range of 1.50-1.57 eV with p-type nature. Finally, photovoltaic devices were fabricated, and their cell performance parameters were studied. An efficiency of 0.16% was observed. The present study provides a potential route for the cost-effective fabrication of CZTS-based photovoltaic devices.

Synthesis of Tunable Band Gap Semiconductor Nickel Sulphide Nanoparticles: Rapid and Round the Clock Degradation of Organic Dyes.

Controlled shape and size with tuneable band gap (1.92-2.41 eV), nickel sulphide NPs was achieved in presence of thiourea or thioacetamide as sulphur sources with the variations of temperature and capping agents. Synthesized NPs were fully characterized by powder XRD, IR, UV-vis, DRS, FE-SEM, TEM, EDX, XPS, TGA and BET. Capping agent, temperature and sulphur sources have significant role in controlling the band gaps, morphology and surface area of NPs. The catalytic activities of NPs were tested for round the clock (light and dark) decomposition of crystal violet (CV), rhodamine B (RhB), methylene blue (MB), nile blue (NB) and eriochrome black T (EBT). Agitation speed, temperature, pH and ionic strength have significant role on its catalytic activities. The catalyst was found to generate reactive oxygen species (ROS) both in presence and absence of light which is responsible for the decomposition of dyes into small fractions, identified with ESI-mass spectra.

Overt and subclinical thyroid dysfunction among Indian pregnant women and its effect on maternal and fetal outcome.

PURPOSE: Thyroid disorders are among the common endocrine problems in pregnant women. It is now well established that not only overt, but subclinical thyroid dysfunction also has adverse effects on maternal and fetal outcome. There are few data from India about the prevalence of thyroid dysfunction in pregnancy. With this background, this study aims to find prevalence of thyroid dysfunction in pregnancy and its impact on obstetrical outcome in Indian population. METHODS: Six hundred and 33 pregnant women in second trimester were registered. Detailed history and examination was done. Apart from routine obstetrical investigations, TSH level estimation was done. If TSH level was deranged then free T4 and thyroperoxidase antibody level estimation were done. Patients were managed accordingly and followed till delivery. Their obstetrical and perinatal outcomes were noted. RESULTS: Prevalence of thyroid dysfunction was high in this study, with subclinical hypothyroidism in 6.47% and overt hypothyroidism in 4.58% women. Overt hypothyroids were prone to have pregnancy-induced hypertension (P=0.04), intrauterine growth restriction (P=0.01) and intrauterine demise (P=0.0004) as compared to control. Cesarean section rate for fetal distress was significantly higher among pregnant subclinical hypothyroid women (P=0.04). Neonatal complications and gestational diabetes were significantly more in overt hyperthyroidism group (P=0.03 and P=0.04, respectively). CONCLUSIONS: Prevalence of thyroid disorders, especially overt and subclinical hypothyroidism (6.47%) was high. Significant adverse effects on maternal and fetal outcome were seen emphasizing the importance of routine antenatal thyroid screening.

Evaluation of pregnant women with scarred uterus in a low resource setting.

AIM: Management of post cesarean pregnancy continues to be a dilemma. The present study was undertaken to evaluate the outcome of such pregnancies in a resource constrained setting so that an appropriate management protocol can be decided. METHODS: An observational study was conducted in the Department Of Obstetrics And Gynecology, King George's Medical University, Lucknow, India. The outcome of all of the women admitted with pregnancy with a previous cesarean section was noted. RESULTS: A total number of 447 women with a post cesarean pregnancy underwent delivery. These comprised 13.7% of total deliveries over the same period. 124 women (27.7%) had successful vaginal delivery while 323 (72.3%) had a repeat cesarean section. Maternal morbidity and perinatal mortality were both significantly higher in the vaginal delivery group (P = 0.00211 and P = 0.0426, respectively). CONCLUSIONS: Vaginal birth after cesarean (VBAC) is associated with higher maternal morbidity and perinatal mortality. Therefore the decision for VBAC must be taken only after proper consideration and counseling of the couple.

Impact of maternal body mass index on obstetric outcome.

AIM: The purpose of the present study was to correlate effect of maternal body mass index (BMI) on obstetric outcome. The studies conducted so far are from Western developed countries and there is a paucity of data from developing countries. METHODS: A prospective evaluation was carried out of 380 women in one unit of a tertiary care teaching hospital in North India from May 2005 to June 2006 on the effect of maternal BMI on pregnancy outcome. BMI was calculated as weight (kg) divided by height (m(2)). BMI was used to characterize women as lean (BMI < 19.8 kg/m(2)), normal (BMI 19.9-24.9 kg/m(2)), overweight (BMI 25-29.9 kg/m(2)) or obese (> or =30 kg/m(2)). RESULTS: Forty-six women (12.1%) out of 380 were underweight, 99 (26.1%) were overweight, 30 (7.9%) were obese and the remaining 205 (53.9%) had normal BMI. Anemia (P = 0.02) and low birthweight (P = 0.008) was significantly present among lean women. Obese women had a significant risk for gestational diabetes (P = 0.0004), pre-eclampsia (P = 0.004), cesarean delivery (P = 0.01) and macrosomia (P = 0.02). CONCLUSION: Both lean and obese women carry a risk for adverse pregnancy outcome, therefore pregnant women should maintain a normal BMI to achieve a healthy pregnancy outcome.

Medical termination of pregnancy in acute intermittent porphyria.

Acute intermittent porphyria is a rare autosomal dominant disease characterized by acute attacks of neuropsychiatric and neurovisceral dysfunction. In pregnancy, exacerbation of attacks in the form of seizures and acute abdomen occur due to hormonal changes. We report the case of a young woman presenting at 8 weeks of gestation requesting pregnancy termination. The patient suffered several episodes of acute abdomen and seizures in a prior pregnancy before the diagnosis was clinched. This case is reported because of its rarity and the limited obstetric experience of this disorder. Proper management depends on avoidance of precipitating factors. Anaesthetic drug safety in porphyria is reviewed and the choice of regional anaesthesia discussed.