DEVELOPMENT AND VALIDATION OF ULTRAVIOLET–VISIBLE SPECTROPHOTOMETRIC METHOD FOR ESTIMATION OF GLYCYRRHIZIN IN METHANOLIC EXTRACT OF GLYCYRRHIZA GLABRA L

Objective: The pure form of glycyrrhizin was bought from Yucca Enterprises, Mumbai-37, India. The pure form of drug used in treatment of acne vulgaris disease. Pharmacognostical studies of Glycyrrhiza glabra L. indicated surprising antibacterial action against Propionibacterium acnes. Methods: A simple, rapid, accurate, precise, and economic spectrophotometric technique for estimation of glycyrrhizin in methanolic extract of G. glabra L. have been developed. Glycyrrhizin exhibit absorbance most at 254 nm when phosphate buffer (pH-6.8) methanol is used as solvent in 70:30 proportion, so absorbance was once measured at the identical wave lengths for the determination of glycyrrhizin. Glycyrrhizin obeys the Beer Lambert’s law in the concentration range of 4–24 μg/ml. Results: This method was validated according to International Council for Harmonization guidelines and can be adopted for the general analysis of glycyrrhizin in hydroalcoholic extract of G. glabra. The approach is simple, rapid, safe, accurate, affordable, and beneficial for standardization of the licorice products. Conclusion: The results applied in the routine analysis and quality control of pharmaceutical dosage forms containing glycyrrhizin

Evaluation of Abaqus for simulating quasi-static Mode III shear of edge notched carbon fiber reinforced polymer panels

The ability to engineer stiffness and strength in any desired direction make composites an ideal material candidate for various applications when compared to their traditional isotropic counterparts. In spite of this, the ability to model the material response in composites has yet to be fully explored. Composite research largely focuses on in-plane conditions and research involving modeling Mode III (out-of-plane shear) is limited. Mode III occurs when adjacent sections of a plate are displaced in opposite out-of-plane directions, thus causing through-thickness tearing. Mode III can potentially lead to catastrophic failure for composite designs with inadequate out-of-plane transverse properties exposed to excessive out-of-plane loads. This can be countered by overdesigning a structure, but at the cost of sacrificing efficiency. Hence it is necessary to have models to appropriately capture material behavior during loading for design and analytical purposes. Commercial finite element (FE) packages are available for simulating various loading conditions, but there has not been an assessment of their applicability for composites enduring Mode III. This study aimed to evaluate the performance of a commercial finite element package, Abaqus, for modeling Mode III loading of edge notched Carbon Fiber Reinforced Polymer panels using previously conducted experiments as a metric. Six ply layups were considered and were composed of either 20 or 40 unidirectional plies. For each thickness, 10%, 30%, and 50% zero-degree panels were studied. Panels also included 45, -45, and 90 degree plies. This investigation was divided into two studies: Evaluation of finite element analysis (FEA) prior to visible damage initiation and evaluation of FEA for progressive failure simulation. The first study utilized strain fields obtained from Digital Image Correlation (DIC) and load versus displacement profiles retrieved from experiments to evaluate elastic based FEA conducted with Abaqus/Standard. Abaqus/Standard was able to simulate strain fields roughly within 30% with the exception of small regions near the notch tip and predict the loads with a percent difference of 20%. The 50% zero-degree panels was an exception in which large discrepancies occurred between experiments and FEA. The second study involved assessing Abaqus/Standard, Abaqus/Standard with the add-in Helius:MCT, and Abaqus/Explicit for simulating progressive failure analyses. Experimentally obtained load versus displacement profiles, damage paths, and maximum loads were used as a metric to evaluate the solvers. It was found that the solvers were not able to predict the complete damage paths. However, Abaqus/Standard and Abaqus/Explicit were able to predict the maximum loads with a percent difference of 20%. Helius:MCT experienced convergence failures using default settings. Although accuracy and predictive capabilities were limited, the solvers were able to provide reasonable approximations for the material behavior

Implementation of a Matrix Crack Spacing Parameter in a Continuum Damage Mechanics Finite Element Model

Continuum Damage Mechanics (CDM) based progressive damage and failure analysis (PDFA) methods have demonstrated success in a variety of finite element analysis (FEA) implementations. However, the technical maturity of CDM codes has not yet been proven for the full design space of composite materials in aerospace applications. CDM-based approaches represent the presence of damage by changing the local material stiffness definitions and without updating the original mesh or element integration schemes. Without discretely representing cracks and their paths through the mesh, damage in models with CDM-based materials is often distributed in a region of partially damaged elements ahead of stress concentrations. Having a series of discrete matrix cracks represented by a softened region may affect predictions of damage propagation and, thus, structural failure. This issue can be mitigated by restricting matrix damage development to discrete, fiber-aligned rows of elements; hence CDM-based matrix cracks can be implemented to be more representative of discrete matrix cracks. This paper evaluates the effect of restricting CDM matrix crack development to discrete, fiber-aligned rows where the spacing of these rows is controlled by a user-defined crack spacing parameter. Initially, the effect of incrementally increasing matrix crack spacing in a unidirectional center notch coupon is evaluated. Then, the lessons learned from the center notch specimen are applied to open-hole compression finite element models. Results are compared to test data, and the limitations, successes, and potential of the matrix crack spacing approach are discussed

IMPACT OF PAKISTANI LABOR MIGRANT NETWORK ON PAKISTAN’S INTERNATIONAL TRADE WITH THE MIDDLE EAST

Emigrants possess knowledge of host and sending countries’cultures and social environments that can help strengthen theeconomic relationship between them. We find this to be true forPakistan and its selected Middle East trading partners for whom thedata are available. Gravity model estimates suggest that eachPakistani emigrant contributed $422 to exports. This increase inexports can be attributed to Pakistani emigrants’ superior knowledgeof both countries environment as well as their help in reducingtransaction costs in trade. This study should be helpful to policymakers, who generally consider migrants to be the source ofremittances only, while our study showed that migrants help broadenour international trade as well

DISCRIMINATION AND CAREER MOBILITY AMONG FEMALE BANK EMPLOYEES

The less representation of women at top managerial levelremained an eye catching issue in organizational studies in therecent past. The current study aimed at revisiting the existingrelationship between gender discrimination and career mobility ina sample of female bank employees. Furthermore, the influence ofsocial norms, work-family balance and self- efficacy as mediatingvariables is examined. Data were collected through self-reportedquestionnaire from female bank employees. Correlation andregression tests were applied using the SPSS. Results indicate thatthere is a negative link between gender discrimination and femalecareer mobility in banks operating in Pakistan

PCA BASED CLASSIFICATION OF SINGLE-LAYERED CLOUD TYPES

The paper presents an automatic classification system, which discriminates the different types of single-layered clouds using Principal Component Analysis (PCA) with enhanced accuracy as compared to other techniques. PCA is an image classification technique, which is typically used for face recognition. PCA can be used to identify the image features called principal components. A principal component is a peculiar feature of an image. The approach described in this paper uses this PCA capability for enhancing the accuracy of cloud image analysis. To demonstrate this enhancement, a software classifier system has been developed that incorporates PCA capability for better discrimination of cloud images. The system is first trained by cloud images. In training phase, system reads major principal features of the different cloud images to produce an image space. In testing phase, a new cloud image can be classified by comparing it with the specified image space using the PCA algorithm

Assessment of Intralaminar Progressive Damage and Failure Analysis Using an Efficient Evaluation Framework

Reducing the timeline for development and certification for composite structures has been a long standing objective of the aerospace industry. This timeline can be further exacerbated when attempting to integrate new fiber-reinforced composite materials due to the large number of testing required at every level of design. computational progressive damage and failure analysis (PDFA) attempts to mitigate this effect; however, new PDFA methods have been slow to be adopted in industry since material model evaluation techniques have not been fully defined. This study presents an efficient evaluation framework which uses a piecewise verification and validation (V&V) approach for PDFA methods. Specifically, the framework is applied to evaluate PDFA research codes within the context of intralaminar damage. Methods are incrementally taken through various V&V exercises specifically tailored to study PDFA intralaminar damage modeling capability. Finally, methods are evaluated against a defined set of success criteria to highlight successes and limitations

Verification and Validation Process for Progressive Damage and Failure Analysis Methods in the NASA Advanced Composites Consortium

The Advanced Composites Consortium is a US Government/Industry partnership supporting technologies to enable timeline and cost reduction in the development of certified composite aerospace structures. A key component of the consortium's approach is the development and validation of improved progressive damage and failure analysis methods for composite structures. These methods will enable increased use of simulations in design trade studies and detailed design development, and thereby enable more targeted physical test programs to validate designs. To accomplish this goal with confidence, a rigorous verification and validation process was developed. The process was used to evaluate analysis methods and associated implementation requirements to ensure calculation accuracy and to gage predictability for composite failure modes of interest. This paper introduces the verification and validation process developed by the consortium during the Phase I effort of the Advanced Composites Project. Specific structural failure modes of interest are first identified, and a subset of standard composite test articles are proposed to interrogate a progressive damage analysis method's ability to predict each failure mode of interest. Test articles are designed to capture the underlying composite material constitutive response as well as the interaction of failure modes representing typical failure patterns observed in aerospace structures

Effects of Soaking and Germination Treatments on the Nutritional, Anti-Nutritional, and Bioactive Characteristics of Adzuki Beans (Vigna angularis L.) and Lima Beans (Phaseolus lunatus L.)

Lima beans (Phaseolus lunatus) and adzuki beans (Vigna angularis) are some of the most nutritious underutilized pulses that are significant in being used as basic ingredients for the preparation of various food products. The present study aimed to determine the impact of soaking and germination on nutritional and bioactive components, in vitro protein digestibility, reducing power, metal chelating capacity, antioxidant activity, and anti-nutritional components of lima and adzuki beans. The findings showed that during the germination treatment, the in vitro protein digestibility of lima and adzuki beans increased by 14.75 and 10.98%, respectively. There was an increase in the antioxidant activity of lima beans by 33.48% and adzuki beans by 71.14% after 72 h of germination, respectively. The reducing power assay of lima and adzuki beans indicated an increase of 49.52 and 36.42%, respectively, during germination. Similarly, the flavonoid and metal chelating activity increased in lima and adzuki beans after 72 h of germination. In contrast, the anti-nutrients, such as phytic acid, tannin content, and trypsin inhibitor activity, decreased significantly p < 0.05 after 72 h of germination. These results are encouraging and allow for utilizing the flour obtained from the germinated beans in functional bakery products, which can contribute to eradicating protein deficiency among some population groups. At the same time, promoting soaking and germination of the beans as a way to enhance the nutritional quality and reduce anti-nutrients can contribute to the interest in these underutilized pulses. They could be seen as an additional tool to improve food security.info:eu-repo/semantics/publishedVersio

A double blind community-based randomized trial of Amoxicillin Versus Placebo for fast breathing Pneumonia in children aged 2-59 months in Karachi, Pakistan (RETAPP)

Background: Fast breathing pneumonia is characterized by tachypnoea in the absence of danger signs and is mostly viral in etiology. Current guidelines recommend antibiotic therapy for all children with fast breathing pneumonia in resource limited settings, presuming that most pneumonia is bacterial. High quality clinical trial evidence to challenge or support the continued use of antibiotics, as recommended by the World Health Organization is lacking. Methods/Design: This is a randomized double blinded placebo-controlled non-inferiority trial using parallel assignment with 1:1 allocation ratio, to be conducted in low income squatter settlements of urban Karachi, Pakistan. Children 2-59 months old with fast breathing, without any WHO-defined danger signs and seeking care at the primary health care center are randomized to receive either three days of placebo or amoxicillin. From prior studies, a sample size of 2430 children is required over a period of 28 months. Primary outcome is the difference in cumulative treatment failure between the two groups, defined as a new clinical sign based on preset definitions indicating illness progression or mortality and confirmed by two independent primary health care physicians on day 0, 1, 2 or 3 of therapy. Secondary outcomes include relapse measured between days 5-14. Modified per protocol analysis comparing hazards of treatment failure with 95 % confidence intervals in the placebo arm with hazards in the amoxicillin arm will be done. Discussion:This study will provide evidence to support or refute the use of antibiotics for fast breathing pneumonia paving a way for guideline change