Andreev reflection near the Dirac point at Graphene - NbSe2 junction

Despite extensive search for about a decade, specular Andreev reflection is only recently realized in bilayer graphene-superconductor interface. However, the evolution from the typical retro type Andreev reflection to the unique specular Andreev reflection in single layer graphene has not yet been observed. We investigate this transition by measuring the differential conductance at the van der Walls interface of single layer graphene and NbSe2 superconductor. We find that the normalized conductance becomes suppressed as we pass through the Dirac cone via tuning the Fermi level and bias energy, which manifests the transition from retro to non-retro type Andreev reflection. The suppression indicates the blockage of Andreev reflection beyond a critical angle of the incident electron with respect to the normal between the single layer graphene and the superconductor junction. The results are compared with a theoretical model of the corresponding setup

Role of histone methyltransferase “EZH2” in human cancer

Epigenetic alternations significantly contribute many disease progressions as the genetic changes do. However, there is a crucial difference between genetic and epigenetic alterations, which has important implications for development of cancer treatments. Therefore it is tough duty and also necessary to identify the all pathways or mechanism by which they work for the development of strategies to impede their abnormal behaviours. Chromatin condensation or relaxation is closely linked with tumorigenesis or cancer by regulating the pattern of gene expression. Methylation is often associated with silencing of many genes. Polycomb group proteins are important for the somatic maintenance of imprinting and for maintaining the silenced state of homeotic genes. The frequent deregulation of PcG activities in human tumors has direct oncogenic effects and results essential for cancer cell proliferation. Ezh2, a Polycomb group protein is the catalytic subunit of PRC2 having conserved SET domain targets H3K27me3. There is little contribution of Ezh2 is known till this date, still H3K27me3 and DNA methylation play a role together in gene silencing by loss of tumor suppression. Ezh2 also linked to histone deacetylation and it is shown that HDAC which is associated to EED is required for PRC2 to perform its function. Here we investigate the functional role of EZH2 in lymph node and gall bladder cancer progression. EZH2 and SUZ12 transcripts were consistently elevated in lymph node carcinoma as compared with normal blood cell. Band intensity analysis demonstrated that EZH2 and SUZ12 protein levels were strongly associated with lymph node cancer aggressiveness. HDAC overexpression in tis cancer supports the EZH2-mediated cell invasion required an intact SET domain and histone deacetylase activity. This study provides the functional link between H3K27me3, DNMTs and HDACs in cancer aggression

An embedded system supporting dynamic partial reconfiguration of hardware resources for morphological image processing

Processors for high-performance computing applications are generally designed with a focus on high clock rates, parallelism of operations and high communication bandwidth, often at the expense of large power consumption. However, the emphasis of many embedded systems and untethered devices is on minimal hardware requirements and reduced power consumption. With the incessant growth of computational needs for embedded applications, which contradict chip power and area needs, the burden is put on the hardware designers to come up with designs that optimize power and area requirements. This thesis investigates the efficient design of an embedded system for morphological image processing applications on Xilinx FPGAs (Field Programmable Gate Array) by optimizing both area and power usage while delivering high performance. The design leverages a unique capability of FPGAs called dynamic partial reconfiguration (DPR) which allows changing the hardware configuration of silicon pieces at runtime. DPR allows regions of the FPGA to be reprogrammed with new functionality while applications are still running in the remainder of the device. The main aim of this thesis is to design an embedded system for morphological image processing by accounting for real time and area constraints as compared to a statically configured FPGA. IP (Intellectual Property) cores are synthesized for both static and dynamic time. DPR enables instantiation of more hardware logic over a period of time on an existing device by time-multiplexing the hardware realization of functions. A comparison of power consumption is presented for the statically and dynamically reconfigured designs. Finally, a performance comparison is included for the implementation of the respective algorithms on a hardwired ARM processor as well as on another general-purpose processor. The results prove the viability of DPR for morphological image processing applications

Enhanced Specular Andreev reflection in bilayer graphene

Andreev reflection in graphene is special since it can be of two types- retro or specular. Specular Andreev reflection (SAR) dominates when the position of the Fermi energy in graphene is comparable to or smaller than the superconducting gap. Bilayer graphene (BLG) is an ideal candidate to observe the crossover from retro to specular since the Fermi energy broadening near the Dirac point is much weaker compared to monolayer graphene. Recently, the observation of signatures of SAR in BLG have been reported experimentally by looking at the enhancement of conductance at finite bias near the Dirac point. However, the signatures were not very pronounced possibly due to the participation of normal quasi-particles at bias energies close to the superconducting gap. Here, we propose a scheme to observe the features of enhanced SAR even at zero bias at a normal metal (NM)-superconductor (SC) junction on BLG. Our scheme involves applying a Zeeman field to the NM side of the NM-SC junction on BLG (making the NM ferromagnetic), which energetically separates the Dirac points for up-spin and down-spin. We calculate the conductance as a function of chemical potential and bias within the superconducting gap and show that well-defined regions of specular- and retro-type Andreev reflection exist. We compare the results with and without superconductivity. We also investigate the possibility of the formation of a p-n junction at the interface between the NM and SC due to a work function mismatch.Comment: 9 pages, 10 captioned figures. Published versio

Open Access Repository: A Comparative study of Germany, Switzerland and Austria

Open access movement has been changed dramatically in recent past years. And it has been supported by individual researchers, institutes, organizations and publishers too. The current paper is a comparative study of Open Access Repositories (OARSs) among three European countries Austria Germany, Switzerland registered in Open Access Repository Ranking (OARSR) (http://repositoryranking.org. ) website. It is also discussed and highlights about open access repositories, operational status, top ten repositories by collection wise and policy etc.. The study found that 181 unique open access repositories in three countries whereas most of the open access repositories found from Germany160 (88.40 %) repositories. Furthermore, the study revealed that 81 (44.75%) repositories are using OPUS software to develop open repositories. Most of the open access repositories are institutional repositories by nature

Comparative study of clomiphene citrate versus letrozole as first-line ovulation induction drug in infertile polycystic ovary syndrome women

Background: Polycystic ovary syndrome is the commonest endocrinopathy resulting in anovulatory infertile young women. Clomifene citrate (clomiphene) is a long-standing standard drug for ovulation induction, and is still considered as first line option in PCOS women. However, clomiphene has certain disadvantage letrozole an aromatase inhibitor acts by reducing estrogen production and has no adverse effects on endometrium and cervical mucous. Indian PCOS women have high prevalence of insulin resistance and thus are likely to have high clomiphene resistance. So letrozole could prove to be a good alternative for ovulation induction in such women.Methods: This was a prospective randomized, parallel, comparative clinical trial of two ovulation induction drugs letrozole 5 mg versus clomiphene citrate 100 mg as first-line ovulation induction drug in infertile polycystic ovarian syndrome women. The target population of the study was one hundred infertile women with PCO (taking at least 2 Rotterdam’s parameters). 50 women were allocated to clomifene citrate and 50 were allocated to Letrozole for ovulation induction. Parameters like age, duration of infertility, B MI, ovulation rate, number of follicles, pregnancy rate, endometrial thickness were noted and analyzed.Results: In letrozole group, the ovulation rate, mono-follicular development, mean endometrial thickness and pregnancy rate was better in comparison to clomifene citrate group.Conclusions: The result of this study suggests that letrozole may replace clomiphene as the first line drug for ovulation induction in infertile PCOS women

Blast Diffusion by Different Shapes of Domes

Domes have been used since ancient times in constructions. These are effective structures in supporting loads for large span. Dome has an added advantage of having good looking in structural applications. Many shapes of domes are being used nowadays for residential, commercial, and industrial purposes. Specific purpose domes are also used for nuclear containment. Main threats to structures are from the bomb blast. Hence, domes too are to be designed to withstand effectively the pressure energy generated by the blast. A comparative theoretical study is proposed on the different shapes of domes having same weight and thickness. Various responses are estimated through numerical method after simulating blast and comparing their intensities.Defence Science Journal, Vol. 65, No. 1, January 2015, pp.77-82, DOI:http://dx.doi.org/10.14429/dsj.65.690