Development of suspended thermoreflectance technique and its application in thermal property measurement of semiconductor materials

Doctor of PhilosophyDepartment of Mechanical and Nuclear EngineeringGurpreet SinghThis dissertation details the development of a new scientific tool for the thermal characterization of freestanding micro/nano-scale materials, with specific application to thin films. The tool consists of a custom-designed and calibrated opto-electric system with superior spatial and temporal resolutions in thermal measurement. The tool, termed as Suspended ThermoReflectance (STR), can successfully perform thermal mappings at the submicron level and is able to produce unconstrained thermal conductivity unlike other optical measurement techniques where independent conductivity measurement is not possible due to their reliance on heat capacity. STR works by changing the temperature of a material and collecting the associated change in light reflection from multiple points on the sample surface. The reflection is a function of the material being tested, the wavelength of the probe light and the composition of the specimen for transparent and quasi-transparent materials. Coupling the change in reflection, along the sample’s length, with the knowledge of heat conduction allows for the determination of the thermal properties of interest. A thermal analytical model is developed and incorporated with optical equations to characterize the conductivity of thin films. The analytical model is compared with a finite element model to check its applicability in the STR experiment and data analysis. Ultimately, thermal conductivity of 2 µm and 3 µm thick Si samples were determined using STR at a temperature range of 20K – 350K and compared to literature as a validation of the technique. The system was automated using a novel LabView-based program. This program allowed the user to control the equipment including electronics, optics and optical cryostat. Moreover, data acquisition and real-time monitoring of the system are also accomplished through this computer application. A description of the development, fabrication and characterization of the freestanding thin films is detailed in this dissertation. For the most part, the thin films were fabricated using standard microfabrication techniques. However, different dry and wet etching techniques were compared for minimum surface roughness to reduce light scattering. The best etching technique was used to trim the Si films for the desired thicknesses. Besides, vapor HF was used to avoid stiction-failure during the release of suspended films

Programs by Extracting UML Class Diagram

The Unified Modeling Language (UML) has been accepted as a standard for modeling object oriented system. It helps the designer to understand a problem well by focusing on one aspects of a problem at a time. In this paper we present a novel approach in which reverse engineering is performed and we have chosen UML as the modeling language to achieve a representation of the implemented system. In this work we have considered java programs. After a brief introduction to the subject, we present some analyses which go beyond mere enumeration of methods and fields. We sketch a method which determines classes and their attribute, operation and relationship: generalization, aggregation, association and various kind of dependencies in form of a simple class diagram that can be understood by a programmer when inspecting the source code of a given java programs. To fully understand the behavior of a system, it is crucial to have efficient techniques to reverse static views of the system. In this paper, we focus on the reverse engineering to find UML class diagram from an object oriented system and analysis of its static behavior

Recent Approaches in Computational Drug Delivery System

Systematizing a state-of-the-art drug delivery (DD) system which can deliver Active Pharmaceutical Ingredient (API) in safe and efficacious way is a premium process which requires years of development. Computational Drug Delivery is a unique way which utilizes computer aided simulations of models based on the Computational Fluid Dynamics (CFD), Volume of Fluid (VOF) technique and Molecular Dynamics (MD) combined with medical imaging techniques such as Computerized Axial Tomography (CAT) Scan, Magnetic Resonance Imaging (MRI) and Ultrasound to simulate in vivo conditions for better understanding of the drug delivery systems. This review article aims at elaborating the distinct approaches of Computational Drug Delivery in nanoparticulate, Microsphere Drug Delivery, liposomal Drug Delivery, brain specific, liver specific, tumour specific targeting along with optimization in traditional methods. Computational drug delivery approaches in the pharmaceutical sciences have the main goal of rational drug discovery and development

Taking stocks of antimalarial activities: A study on knowledge and skill of health personnel at primary care setting in the state of West Bengal, India

Background: Early diagnosis and effective treatment are the key areas in malaria control in India. Objective: The present study was carried out to assess the knowledge and skill of health personnel at primary care level and the logistic support related to the program at subcenter (SC) level. Methods: A cross-sectional, descriptive study was conducted among medical and paramedical personnel working at primary health-care institutions in two districts of West Bengal. Knowledge was assessed using a structured questionnaire while diagnostic skill and logistic support were assessed with structured checklists. Clinical skill was assessed with case vignettes. Results: Requisite knowledge on diagnostic procedure was found in two-third to three-fourth of health personnel while only 26.7% and 12.4%, respectively, knew the correct treatment of Plasmodium vivax and Plasmodium falciparum malaria. Median standardized score for knowledge was 50.0 while the scores for skill of preparing blood slide and for rapid diagnostic test were 70.0 and 57.1, respectively. Education and work experience were related to diagnostic skill but had little effect on knowledge. In clinical skill, medical personnel scored 50% or more in investigation and treatment aspects only. In another case vignette, health workers excelled over medical officers and other staff in all axes other than history taking and clinical examination although their performance was also suboptimal. Formal training on malaria did not show any bearing on median knowledge and skill score. Supply of diagnostics and drugs was insufficient in majority of SCs. Conclusion: Renewed efforts are needed to create competent workforce and ensure adequate logistic supply

Quercetin and/or Ascorbic Acid Modulatory Effect on Phenobarbital-Induced Sleeping Mice Possibly through GABAA and GABAB Receptor Interaction Pathway

Depressive disorder is a recurrent illness that affects large numbers of the general population worldwide. In recent years, the goal of depression treatment has moved from symptomatic response to that of full remission. However, treatment-resistant depression is a major challenge in the treatment of depression or depression-related disorders. Consensus opinion, therefore, suggests that effective combined aggressive initial treatment is the most appropriate strategy. This study aimed to evaluate the effects of quercetin (QUR) and/or ascorbic acid (AA) on Phenobarbital-induced sleeping mice. QUR (50 mg/kg) and/or AA (25 mg/kg) with or without intraperitoneally pre-treated with GABA receptor agonist (diazepam: 2 mg/kg, i.p.) or antagonist (Flumazenil: 2.5 mg/kg, i.p.) to underscore the effects, as well as the possible involvement of the GABA receptor in the modulatory action of QUR and AA in sleeping mice. Additionally, an in silico study was undertaken to predict the involvement of GABA receptors in the sleep mechanism. Findings suggest that the pretreatment of QUR and AA modulated the onset and duration of action of the standard drugs in experimental animals. The acute administration of QUR and/or AA significantly (p < 0.05) reversed the DZP-mediated onset of action and slightly reversed the duration of sleep time in comparison to the vehicle (control) group. A further combination of QUR or AA with the FLU resulted in an enhancement of the onset of action while reducing the duration of action, suggesting a FLU-like effect on the test animals. In in silico studies, AA and QUR showed good to moderate binding affinities with GABAA and GABAB receptors. Both QUR and AA produced a stimulatory-like effect on mice, possibly through the GABAA and GABAB receptor interaction pathways. Further studies are necessary to verify this activity and clarify the exact mechanism of action(s) involved