Dvali-Gabadadze-Porrati Cosmology in Bianchi I brane

The dynamics of Dvali-Gabadadze-Porrati Cosmology (DGP) braneworld with an anisotropic brane is studied. The Friedmann equations and their solutions are obtained for two branches of anisotropic DGP model. The late time behavior in DGP cosmology is examined in the presence of anisotropy which shows that universe enters a self-accelerating phase much later compared to the isotropic case. The acceleration conditions and slow-roll conditions for inflation are obtained

DEVELOPMENT AND VALIDATION OF STABILITY INDICATING RP-HPLC METHOD FOR THE SIMULTANEOUS ESTIMATION OF ALISKIREN HEMIFUMARATE AND VALSARTAN IN BULK AND PHARMACEUTICAL DOSAGE FORM

Objective: A new, simple, selective, and reproducible stability indicating reversed - phase high performance liquid chromatography method for thesimultaneous estimation of Aliskiren (ALN) Hemifumarate and Valsartan (VLN) in bulk drug, and tablet dosage form was developed and validated asper ICH guidelines.Methods: The chromatographic separation was performed using a nucleosil C - 18 column and the analytes were detected by a malondialdehyde - 2010photodiode array detector. The mobile phase composed of methanol: potassium dihydrogen ortho phosphate buffer (adjusted to pH 3 withorthophosphoric acid). The flow rate was set at 1 ml/minutes, and the detection was carried out at 225 nm.Results: ALN Hemifumarate and VLN showed a retention time of 3.84 and 5.96 minutes, respectively. The linear dynamic range was found to be5-50 mcg/ml and 5-30 mcg/ml with a co-relation co-efficient of 0.992 and 0.985 for ALN and VLN, respectively, with mean percentage recoveries of99.95% and 99.25%. The results were validated and were found to successfully obey the parameters as per ICH guidelines.Conclusion: Hence, the method can be successfully applied for routine quality control analysis and stability studies for both ALN Hemifumarate andVLN in bulk and tablet dosage form as per regulatory requirements.Keywords: Aliskiren Hemifumarate, Valsartan, Reversed-phase high performance liquid chromatography, Stress degradation study, ICH guidelines

Therapeutic hypothermia and ischemic stroke: A literature review

BACKGROUND: Ischemic stroke is the fifth leading cause of death in the US. Clinical techniques aimed at helping to reduce the morbidity associated with stroke have been studied extensively, including therapeutic hypothermia. In this study, the authors review the literature regarding the role of therapeutic hypothermia in ischemic stroke to appreciate the evolution of hypothermia technology over several decades and to critically analyze several early clinical studies to validate its use in ischemic stroke. METHODS: A comprehensive literature search was performed using PubMed and Google Scholar databases. Search terms included hypothermia and ischemic stroke and therapeutic hypothermia. A comprehensive search of the current clinical trials using clinicaltrials.gov was conducted using the keywords stroke and hypothermia to evaluate early and ongoing clinical trials utilizing hypothermia in ischemic stroke. RESULTS: A comprehensive review of the evolution of hypothermia in stroke and the current status of this treatment was performed. Clinical studies were critically analyzed to appreciate their strengths and pitfalls. Ongoing and future registered clinical studies were highlighted and analyzed compared to the reported results of previous trials. CONCLUSION: Although hypothermia has been used for various purposes over several decades, its efficacy in the treatment of ischemic stroke is debatable. Several trials have proven its safety and feasibility; however, more robust, randomized clinical trials with large volumes of patients are needed to fully establish its utility in the clinical setting

A Marketplace for Efficient and Secure Caching for IoT Applications in 5G Networks

As the communication industry is progressing towards fifth generation (5G) of cellular networks, the traffic it carries is also shifting from high data rate traffic from cellular users to a mixture of high data rate and low data rate traffic from Internet of Things (IoT) applications. Moreover, the need to efficiently access Internet data is also increasing across 5G networks. Caching contents at the network edge is considered as a promising approach to reduce the delivery time. In this paper, we propose a marketplace for providing a number of caching options for a broad range of applications. In addition, we propose a security scheme to secure the caching contents with a simultaneous potential of reducing the duplicate contents from the caching server by dividing a file into smaller chunks. We model different caching scenarios in NS-3 and present the performance evaluation of our proposal in terms of latency and throughput gains for various chunk sizes

Bulk scalar field in DGP braneworld cosmology

We investigated the effects of bulk scalar field in the braneworld cosmological scenario. The Friedmann equations and acceleration condition in presence of the bulk scalar field for a zero tension brane and cosmological constant are studied. In DGP model the effective Einstein equation on the brane is obtained with bulk scalar field. The rescaled bulk scalar field on the brane in the DGP model behaves as an effective four dimensional field, thus standard type cosmology is recovered. In present study of the DGP model, the late-time accelerating phase of the universe can be explained .Comment: 10 pages, to appear in JCA

STABILITY INDICATING ANALYTICAL METHOD DEVELOPMENT AND VALIDATION OF MEMANTINE HCl AND DONEPEZIL HCl USING RP-HPLC

Objective: To develop and validate stability indicating method for the analysis of Memantine HCl and Donepezil HCl.Methods: The chromatographic separation was performed on Hypersil BDS (4.6 x 150 mm, 5m) using Sodium dihydrogen ortho phosphate: Acetonitrile (30:70v/v) at a flow rate of 1 ml/min and detection of both the eluents was carried out by UV Detector.Results: The Retention time of Memantine HCl and Donepezil HCl were found to be 2.833 min. and 4.777 min respectively. Method was found to be linear over the range of 40-120μg/ml for Memantine HCl and 20-60μg/ml for Donepezil HCl. Percentage recovery of Memantine HCl and Donepezil HCl was found to be 99.62% and 99.45% respectively. The percentage purity thus found is 98.5% and 98.6% for Memantine HCl and Donepezil HCl. The Limit of Detection of Memantine HCl and Donepezil HCl is 3.69 mg/ml and 2.72 mg/ml. and Limit of Quantification of Memantine HCl and Donepezil HCl is 11.13 mg/ml and 8.25 mg/ml respectively. In the stress degradation studies, it was found that Memantine HCl and Donepezil HCl showed no degradation in acid (0.1M HCl), base (0.1M NaOH), peroxide, heat and sunlight.Conclusion: A new sensitive, simple, and stability indicating high performance layer chromatographic (HPLC) method has been developed and validated for determination of Memantine HCl and Donepezil HCl. The proposed method can be used for routine determination of Memantine HCl and Donepezil HCl stability.Â

Outcomes of Subtrochanteric Fractures; A Prospective Study Focusing on the Comparison of Open and Closed Surgical Technique

Objective: To review the outcome of surgery by looking at function, deformity and pain according to Harris Hip Score comparing two surgical procedures i.e. open technique and closed technique using relatively recently developed implants. Methodology: This comparative prospective study was conducted in the department of orthopaedic surgery PIMS Islamabad, from June 2013 to May 2015. By using purposive sampling patients aged 20-50 years with closed subtrochanteric fractures of less than 2 weeks duration were included in the study. The patients with open fractures, pathological fractures, multiple fractures/ poly trauma, and old and neglected fractures of more than 2 weeks were excluded. All included cases of subtrochanteric fractures were managed by either closed technique, using Proximal Femur nail (PFN) or open technique using a Proximal Femur anatomical locking plate (PFP). This comparative study was planned to determine union rates, complications & functional outcome of fixation of subtrochanteric fractures.  Descriptive analysis was done using SPSS version 20. Chi-square test was applied for comparing qualitative variables.Results: A total of 100 cases were included in the study with the mean age was 38.5 ± 8.6 years in the open technique group () while 34.6 ± 1.2 years in closed technique (). There are 72 males and 28 females.  Union occurred 84% in open technique and 96% in closed technique.  In open technique group mean Harris hip score was 68.9 ±5.4 compared to 72.4 ± 6.2 in the closed technique group (p-value <0.001). In open technique group 6 (12.0%) cases had delayed union and 2 (4.0%) had non-union compared to 3 (6.0%) cases and 1 (2.0%) cases in closed technique group respectively.Conclusion: Outcome favours closed technique compared to open technique for subtrochanteric fractures fixation, when assessed on Harris hip Score. There was no statistically significant difference in the fracture union and frequency of complications between the two groups

Defect engineering for improved photocatalytic performance of reduced lead titanate (PbTiO3) under solar light irradiation

Lead titanate (PbTiO3) nanoparticles were prepared successfully by template free hydrothermal  method. Size, crystallinity, morphology and phase determination of the nanoparticles were made by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and field-emission scanning electron microscopy (FESEM). FESEM results had shown that all nanoparticles were in the range between 20 to 40 nm size and found in the form of agglomerates. The average crystallite size of PbTiO3 nanoparticles was calculated to be nearly 35 nm. PbTiO3 nanoparticles were reduced by hydrogenation at high temperature to make the material active for visible light. Furthermore, optical absorbance of PbTiO3 nanoparticles was determined by applying ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. By using Davis-Mott model, the direct optical band gap of 2.65 eV was acquired. Methyl orange (MO) was used as pollutant to check the photocatalytic activity of reduced PbTiO3 nanoparticles under solar light irradiation. Photocatalytic activity of reduced PbTiO3 nanoparticles increased 2.6 times more than that of pure PbTiO3 nanoparticles for methyl orange (MO) under solar light irradiation.               KEY WORDS: Lead titanate (PbTiO3), Photocatalytic performance, Hydrothermal growth, Solar light, Irradiation Bull. Chem. Soc. Ethiop. 2019, 33(2), 373-380.DOI: https://dx.doi.org/10.4314/bcse.v33i2.1

Challenges in compression testing of 3D angle-interlocked woven-glass fabric-reinforced polymeric composites.

This paper describes the challenges in using testing standards such as D6641/D6641M-14, for determination of compressive strength of 3D angle interlocked glass fabric reinforced polymeric composites (3D-FRPC). It makes use of both experimental investigation and finite element analysis. The experimental investigation involved testing both 2D and 3D-FRPC using ASTM D6641/D6641M-14 and subsequent scanning electron microscopic imaging of failed specimens to reveal the stress state at failure. This was further evaluated using laminate level finite element (FE) analysis. The FE analysis required input of effective orthotropic elastic material properties of 3D-FRPC, which were determined by customizing a recently developed micro-mechanical model. The paper sheds new light on compressive failure of 3D angle interlocked glass fabric composites, as only scarce data is available in literature about this class of materials. It showed that although the tests produce acceptable strength values the internal failure mechanisms change significantly and the standard deviation (SD) and coefficient of variance (COV) of 3D-FRPC comes out to be much higher than that of 2D-FRPC. Moreover, while reporting and using the test data some additional information about the 3D-fabric architecture, such as the direction of angle interlocking fabric needs to be specified. This was because, for 3D angle interlocking of fabric along warp direction, the strength values obtained in the warp and weft direction were significantly different from each other. The study also highlights that due to complex weave architecture it is not possible to achieve comparable volume fractions with 2D and 3D fabric reinforced composites using similar manufacturing parameters for the vacuum assisted resin infusion process. Thus, the normalized compressive strength values (normalized with respect to volume fraction) are the highest for 3D-FRPC when measured along the warp direction, they are at an intermediate level for 2D-FRPC and the lowest for 3D-FRPC, when measured in the weft direction.DelPHE 780 Project grant (DFID UK