Mechanism of photoluminescence enhancement and quenching in Nd2O3 nanoparticles-ferroelectric liquid crystal nanocomposites

The mechanism of photoluminescence enhancement and quenching in np-Nd2O3: FLC nanocomposites has been explored in the current study by UV-Vis and photoluminescence (PL) spectroscopy techniques. UV-Vis absorption spectra of Nd2O3 NPs in the 200-800 nm range shows two absorptions at 248 nm and 292 nm whereas pure FLC gives a broad absorption in the 265 nm to 348 nm region. PL emission intensity of np-Nd2O3: FLC composites recorded at 248 nm excitation wavelength where Nd2O3 NPs show intense emission, increases with gradually increasing the concentration of NPs up to 8 mu l. This enhancement in PL intensity without blue/red shifting the FLC's emission band was attributed to the up-conversion of doped Nd3+ ions and transfer of excitation energy to liquid crystal molecules. When excited with 248 nm, the Nd3+ ground state I-4(9/2) absorption excites electrons to a higher excited state (2)G(5/2). The excited Nd3+ ions in (2)G(5/2) level relax non-radiatively to the metastable H-2(11/2) state and then re-excites to an unstable (4)G(11/2) level. The electrons populated in (4)G(11/2) release energy either radiatively to different defect energy levels in the visible region or transfers this excitation energy to liquid crystal molecules which resulted into the enhancement in PL emission intensity. On the other hand, emission spectra at 303, 323, 333, 343 nm excitation wavelengths exhibit quenching of all emission bands in np-Nd2O3: FLC composites due to the stress induced structural disordering by the Nd2O3 NPs in the FLC matrix and creation of non-radiative channels in the system

Mechanism of visible-light-driven photocatalytic degradation of endosulfan pesticide by gold nanoparticles

Spherical shaped gold nanoparticles (GNPs) of size around similar to 9 nm were successfully used for photocatalytic degradation of hazardous endosulfan (ES) pesticide. GNPs absorb sunlight at ambient condition in aqueous medium to enhance localized surface plasmon resonance (LSPR) which initiate hydrolysis, oxidation and reduction chemical reactions for the mineralization of ES molecules. Infrared transmittance spectra of GNPs treated ES solutions revealed formation of amorphous carbon and hydrocarbon as final reaction products indicating the nearly complete mineralization of ES as evidenced from their TEM images also. The disappearance of chloro carbon and sulphite functional groups peaks of ES in IR transmittance spectra confirmed their degradation. TEM images also support the optical absorption spectra consisting of inter-band and LSPR bands pertaining to individual and clustered GNPs ensembles. The redshift in LSPR absorption peak positions along minor and major axis of clustered GNPs ensembles is attributed to the change in GNPs polarizability on interaction with the electric component of visible light. The chemical reaction pathway for ES molecule degradation by the photocatalytic GNPs has been proposed in the light of inferences drawn from TEM images, IR transmittance and optical absorption spectra

Development and Optimization of Fast Dissolving Tablets of Losartan Potassium Using Natural Gum Mucilage

Current research work involves preparation of fast dissolving tablets of Losartan Potassium by direct compression method using different concentrations of Plantago ovata and Lepidium sativum mucilage as natural superdisintegrants. A two factor three level (32) factorial design is being used to optimize the formulation. Nine formulation batches (A1-A9) were prepared by taking two factors as independent variables (X1- amount of Plantago ovata mucilage and X2- amount of Lepidium sativum mucilage)were taken with three levels (+1, 0, -1). All the active blends were evaluated for precompression parameters (angle of repose, bulk density, carr’s index, hausner’s ratio) and formulated tablets were evaluated for post compression parameters (hardness, friability, weight variation, wetting time, disintegration time, water absorption ratio). In vitro drug release studies were carried out using USP II dissolution apparatus for 30 min. The software Design Expert (8.0.7.1) was used for generating experimental design, modeling the response surface and calculating the statistical evaluation. Tablet parametric tests of formulation batches (A1-A9) of FDT were found within prescribed limits.DT was observed in the range from 12±2 to 58.7±2.52 sec and WT from 10.3±1.52 to 49.7±5.13 sec for formulation batches (A1-A9). More than 87% drug release was observed in all formulation batches (A1-A9) within 15 minutes. Polynomial mathematical models, generated for various response variables using multiple linear regression analysis, were found to be statistically significant (P < 0.05). Formulation A7 was selected by the design expert software which exhibited DT (22.15sec), WT (17.31sec) and in vitrodrug release (100%) within 15 minutes

Microneedle Mediated Vaccine Delivery: A Comprehensive Review

Microneedles can be representative for paradigm shift of drug delivery from patient non-compliant parenteral injections to patient compliant drug delivery system, which can be utilized for administration of vaccines particularly along with macromolecular/micromolecular drugs. The concept of microneedles came into existence many decades ago but the use of microneedles to achieve efficient delivery of drugs into the skin became subject of research from mid of 1990’s. Various types of microneedles were utilized to enhance delivery of drugs and vaccines including solid microneedles for pre-treatment of skin to enhance drug permeability, dissolvable polymeric microneedles encapsulating drugs, microneedles coated with drugs and hollow microneedles for infusion of drugs through the skin. Microneedles have shown promisingdelivery of vaccines through skin in literature. But the successful utilization of this system for vaccine drug delivery mainly depends on design of device to facilitate microneedle infusion, vaccine stability and storage in system, recovery of skin on removal of microneedle and improved patient compliance. This article reviews the conventional and advanced methods of vaccine drug deliver, microneedles for drug delivery, types of microneedles, advantages of microneedles and potential of microneedles for vaccine drug delivery

Retrospective study of cases of rupture uterus

Background: This study aimed to evaluate the risk factors, clinical presentation, management, maternal and perinatal outcome of patients with rupture uterus.Methods: In this study, clinical records of 14 cases of rupture uterus occurring between January 2001 to August 2004 were reviewed.Results: During this period 17312 deliveries were conducted and 14 cases of rupture uterus were managed. Incidence of rupture uterus was 0,8/1000 deliveries. In 10/14 (71.4%) of cases, rupture occurred in scarred uterus (either of cesarean delivery or of any surgery).9/14 (64.2%) women had rupture of previous cesarean section scar and 4/14 (28.5%) women had rupture of unscarred uterus .7/14 (50%) women had more than one risk factor responsible for rupture uterus. 10/14 (71.4%) women were unbooked.10/14 (71.4%) women had subtotal hysterectomy; 4/14 (28.5%) had repair of scar site. Invariably blood had to be transfused in every case per and post-operatively.6/14 (42.8%) of fetuses could be salvaged; in 7/14 (50%) women; there was intrauterine death, while another (7.14%) woman had preterm neonatal death.Conclusions: Uterine rupture is a preventable complication. In our study, most of women had no antenatal check-up and/or managed initially by untrained personnel. Antenatal and intranatal care, identification of high-risk cases and education of the people about supervised pregnancy and delivery will reduce the occurrence of uterine rupture

Evolution of excitation wavelength dependent photoluminescence in nano-CeO2 dispersed ferroelectric liquid crystals

The optical properties of nano-ceria (nano-CeO2) dispersed ferroelectric liquid crystals (FLCs) have been investigated by excitation wavelength dependent photoluminescence (PL) spectroscopy. The PL spectra of nano-ceria exhibited a strong excitation wavelength dependence in the 255-370 nm range. The red shift in the violet emission band of ceria i.e. from 368 nm to 396 nm with increasing excitation wavelength, has been attributed to the recombination of electrons trapped in the defect band and the deeply trapped holes in oxygen vacancies. This excitation wavelength dependence of ceria has noticeably been manifested in the PL response of FLC-CeO2 nanocomposites as well. PL emission recorded at an excitation wavelength where host and guest materials show intense emission, i.e. 340 nm, exhibits a quenching effect connected to the overlapping of emission and absorption bands of the host FLC and guest ceria NPs respectively. No blue/red shift in the spectral energy band was observed at 310 and 340 nm excitations. On the other hand, emission spectra at a lower excitation wavelength followed a reverse trend: an increase in the emission intensity, with a large blue shift in spectral energy band. The mechanisms involved in the changes of the PL spectrum of FLC-ceria nanocomposites with varying ceria concentration and excitation wavelengths are discussed in detail

Prevalence of various urogynaecological problems and their subsequent management with outcome amongst women attending a tertiary care hospital of a developing Country

Background: The prevalence of urogynaecological problems may be significantly underestimated since the physicians rarely ask women about these problems and women seldom initiate discussion about these symptoms on their own with the physician.Methods: The present study was conducted from March 2006 to August 2008. All the women between 20 to 80 years of age with varying parity attending gynecological outpatient department were evaluated for urogynaecological and bowel problems, based on a questionnaire incorporating demographic and urogynaecological symptoms (IUGA terminology). The frequency of various urinary problems was correlated with the demographic data, urodynamic studies and cystoscopic findings, whenever appropriate and available. Exclusion criteria: The women with disorders of central nervous system, retention urine and pregnancy were excluded from the study.Results: During this period, 15100 women attended outpatient department of gynecology. Out of these, 376 women had urogynaecological and bowel problems. The prevalence of urogynaecological and bowel problems was 24.9 per 1000 women. The incidence of symptoms was dysuria in 38.5 % women, increased frequency of micturition in 38% women; feeling of something coming out per vaginum in 37% women, nocturia in 27.6 % women and pain lower abdomen in 25 % women.Conclusions: Amongst incontinence, 31.3% women had stress incontinence, 25% women had urge incontinence, 14.6% women had urgency, 8.7% women had continuous urinary incontinence and 2.12% women had anal incontinence