Single event upset hardened CMOS combinational logic and clock buffer design

A radiation strike on semiconductor device may lead to charge collection, which may manifest as a wrong logic level causing failure. Soft errors or Single Event Upsets (SEU) caused by radiation strikes are one of the main failure modes in a VLSI circuit. Previous work predicts that soft error rate may dominate the failure rate in VLSI circuit compared to all other failure modes put together. The issue of single event upsets (SEU) need to be addressed such that the failure rate of the chips dues to SEU is in the acceptable range. Memory circuits are designed to be error free with the help of error correction codes. Technology scaling is driving up the SEU rate of combinational logic and it is predicted that the soft error rate (SER) of combinational logic may dominate the SER of unpro-tected memory by the year 2011. Hence a robust combinational logic methodology must be designed for SEU hardening. Recent studies have also shown that clock distribution network is becoming increasingly vulnerable to radiation strike due to reduced capaci-tance at the clock leaf node. A strike on clock leaf node may propagate to many flip-flops increasing the system SER considerably. In this thesis we propose a novel method to improve the SER of the circuit by filtering single event upsets in the combinational logic and clock distribution network. Our ap-proach results in minimal circuit overhead and also requires minimal effort by the de-signer to implement the proposed method. In this thesis we focus on preventing the propagation of SEU rather than eliminating the SEU on each sensitive gate

One-Dimensional Organometallic V-Anthracene Wire and Its B-N Analogue: Efficient Half-Metallic Spin Filters

Using density functional theory, we have investigated the structural, electronic and magnetic properties of infinitely periodic organometallic vanadium-anthracene ([V_2Ant]_\infinity) and [V_4(BNAnt)_2]_\infinity(where BNAnt is B-N analogue of anthracene) for their possible application in spintronics. From our calculations, we find that one-dimensional [V_2Ant]_\infinity and [V_4(BNAnt)_2]_\infinity wires exhibit robust ferromagnetic half-metallic and metallic behavior, respectively. The finite sized $V_6Ant_2$ and $V_6(BNAnt)_2$ clusters are also found to exhibit efficient spin filter properties when coupled to graphene electrodes on either side

Unified Payments Platform for Businesses

Businesses provide a variety of payment options, but this can make it difficult to streamline the payment infrastructure. This can restrict the ability of businesses to offer customized financial solutions to their customers. This disclosure describes a unified payments platform that integrates with other payment systems and is an interface to business customers to integrate it. The platform provides businesses with a unified view of customer order history and invoices, irrespective of payment services selected. It also offers features such as trial periods, discounts/ cashback, subscriptions/ loyalty programs, and cost estimates. Additionally, the platform can provide notification services with preconfigured communications templates

Hemagglutinin sequence conservation guided stem immunogen design from influenza A H3 subtype

Seasonal epidemics caused by influenza A (H1 and H3 subtypes) and B viruses are a major global health threat. The traditional, trivalent influenza vaccines have limited efficacy because of rapid antigenic evolution of the circulating viruses. This antigenic variability mediates viral escape from the host immune responses, necessitating annual vaccine updates. Influenza vaccines elicit a protective antibody response, primarily targeting the viral surface glycoprotein hemagglutinin (HA). However, the predominant humoral response is against the hypervariable head domain of HA, thereby restricting the breadth of protection. In contrast, the conserved, subdominant stem domain of HA is a potential ‘universal’ vaccine candidate. We designed an HA stem-fragment immunogen from the 1968 pandemic H3N2 strain (A/Hong Kong/1/68) guided by a comprehensive H3 HA sequence conservation analysis. The biophysical properties of the designed immunogen were further improved by C-terminal fusion of a trimerization motif, ‘isoleucine-zipper’ or ‘foldon’. These immunogens elicited cross-reactive, antiviral antibodies and conferred partial protection against a lethal, homologous HK68 virus challenge in vivo. Furthermore, bacterial expression of these immunogens is economical and facilitates rapid scale-up

Azlocillin can be the potential drug candidate against drug-tolerant Borrelia burgdorferi sensu stricto JLB31.

Lyme disease is one of most common vector-borne diseases, reporting more than 300,000 cases annually in the United States. Treating Lyme disease during its initial stages with traditional tetracycline antibiotics is effective. However, 10-20% of patients treated with antibiotic therapy still shows prolonged symptoms of fatigue, musculoskeletal pain, and perceived cognitive impairment. When these symptoms persists for more than 6 months to years after completing conventional antibiotics treatment are called post-treatment Lyme disease syndrome (PTLDS). Though the exact reason for the prolongation of post treatment symptoms are not known, the growing evidence from recent studies suggests it might be due to the existence of drug-tolerant persisters. In order to identify effective drug molecules that kill drug-tolerant borrelia we have tested two antibiotics, azlocillin and cefotaxime that were identified by us earlier. The in vitro efficacy studies of azlocillin and cefotaxime on drug-tolerant persisters were done by semisolid plating method. The results obtained were compared with one of the currently prescribed antibiotic doxycycline. We found that azlocillin completely kills late log phase and 7-10 days old stationary phase B. burgdorferi. Our results also demonstrate that azlocillin and cefotaxime can effectively kill in vitro doxycycline-tolerant B. burgdorferi. Moreover, the combination drug treatment of azlocillin and cefotaxime effectively killed doxycycline-tolerant B. burgdorferi. Furthermore, when tested in vivo, azlocillin has shown good efficacy against B. burgdorferi in mice model. These seminal findings strongly suggests that azlocillin can be effective in treating B. burgdorferi sensu stricto JLB31 infection and furthermore in depth research is necessary to evaluate its potential use for Lyme disease therapy

Intrinsic Half-Metallicity in Modified Graphene Nanoribbons

We perform first-principles calculations based on density functional theory to study quasi one-dimensional edge-passivated (with hydrogen) zigzag graphene nanoribbons (ZGNRs) of various widths with chemical dopants, boron and nitrogen, keeping the whole system isoelectronic. Gradual increase in doping concentration takes the system finally to zigzag boron nitride nanoribbons (ZBNNRs). Our study reveals that, for all doping concentrations the systems stabilize in anti-ferromagnetic ground states. Doping concentrations and dopant positions regulate the electronic structure of the nanoribbons, exhibiting both semiconducting and half-metallic behaviors as a response to the external electric field. Interestingly, our results show that ZBNNRs with terminating polyacene unit exhibit half-metallicity irrespective of the ribbon width as well as applied electric field, opening a huge possibility in spintronics device applications.Comment: 4 pages, 5 figures (low resolution), accepted for publication in Physical Review Letter

A Single Dose TMV-HA Vaccine Protects Mice from H5N1 Influenza Challenge

Recombinant subunit vaccines are an efficient strategy to meet the demands of a possible influenza pandemic, because of rapid and scalable production. However, vaccines made from recombinant Hemagglutinin (HA) subunit protein are often of low potency, requiring repeated boosting to generate a sustained immune response. Previously, we demonstrated improved immunogenicity of a plant-made H1 Hemagglutinin (HA) vaccine by chemical conjugation to the surface of the Tobacco Mosaic Virus (TMV) which is non infectious in mammals. Antigen coated TMV is taken up by mammalian dendritic cells and is a highly effective antigen carrier for subunit protein vaccines. In this work, we tested the effectiveness of a TMV-H5 HA conjugate vaccine. We compared the TMV-H5 immunogenicity in mice, with and without an oil-in water squalene adjuvant, to H5N1 virus or HA protein alone, as measured by anti-H5 IgG titers and Hemagglutination Inhibition (HAI). We then evaluated the efficacy of the TMV-H5 vaccine by lethal H5N1 virus challenge in mice. Our results show that a single dose of the TMV-H5 conjugate vaccine is sufficient to generate 40% survival, similar to H5 protein given with adjuvant, or 100% survival after vaccination with adjuvant, similar to H5N1 virus vaccination

In Planta Production of Flock House Virus Transencapsidated RNA and Its Potential Use as a Vaccine

We have developed a transencapsidated vaccine delivery system based on the insect virus, Flock House virus (FHV). FHV is attractive due to its small genome size, simple organization, and non-pathogenic characteristics. With the insertion of a Tobacco mosaic virus (TMV) origin of assembly (Oa), the independently replicating FHV RNA1 can be transencapsidated by TMV coat protein. In this study we demonstrated that the Oa adapted FHV RNA1 transencapsidation process can take place in planta, by using a bipartite plant expression vector system, where TMV coat protein is expressed by another plant virus vector, Foxtail mosaic virus (FoMV). Dual infection in the same cell by both FHV and FoMV was observed. Though an apparent classical coat protein-mediated resistance repressed FHV expression, this was overcome by delaying inoculation of the TMV coat protein vector by three days after FHV vector inoculation. Expression of transgene marker in animals by these in vivo generated transencapsidated nanoparticles was confirmed by mouse vaccination, which also showed an improved vaccine response compared to similar in vitro produced vaccines

Stalking influenza by vaccination with pre-fusion headless HA mini-stem.

Inaccuracies in prediction of circulating viral strain genotypes and the possibility of novel reassortants causing a pandemic outbreak necessitate the development of an anti-influenza vaccine with increased breadth of protection and potential for rapid production and deployment. The hemagglutinin (HA) stem is a promising target for universal influenza vaccine as stem-specific antibodies have the potential to be broadly cross-reactive towards different HA subtypes. Here, we report the design of a bacterially expressed polypeptide that mimics a H5 HA stem by protein minimization to focus the antibody response towards the HA stem. The HA mini-stem folds as a trimer mimicking the HA prefusion conformation. It is resistant to thermal/chemical stress, and it binds to conformation-specific, HA stem-directed broadly neutralizing antibodies with high affinity. Mice vaccinated with the group 1 HA mini-stems are protected from morbidity and mortality against lethal challenge by both group 1 (H5 and H1) and group 2 (H3) influenza viruses, the first report of cross-group protection. Passive transfer of immune serum demonstrates the protection is mediated by stem-specific antibodies. Furthermore, antibodies indudced by these HA stems have broad HA reactivity, yet they do not have antibody-dependent enhancement activity