gebhart/patrepeval huggingface dataset:
Performance-Enhancing Materials for Future Generation Explosives and Propellants (2012)

Abstract : During this grant, SRI has made progress in areas of interest to Navy work thrusts, specifically ammonium perchlorate oxidizer replacement and candidates for insensitive munitions. N-oxidation of nitro-heterocycles can boost oxygen content and increase density of the parent material. Through this work, synthesis methodology for more difficult ring N-oxidation of a variety of nitroheterocycles has been expanded. SRI has explored the limits of N-oxidation using hypofluorous acid (HOF) and persulfate (OXONE) of a variety of nitro substituted 1,2,4-triazoles, 1,2,3-traizoles and imidazoles. SRI also explored the synthesis of a variety of 5/6/5 and 5/5 fused heterocycle ring systems. SRI also explored the synthesis and properties of over-oxidized trinitromethyl (Cring-C(NO2)3) substituted heterocycles. Several examples of 1,2,4-triazole and bi-1,2,4-triazoles with trinitromethyl substitution were synthesized and characterized. This grant has generated several compounds that hold promise as candidates for replacement of ammonium propellant formulations, and/or insensitive munitions and require further investigation.
Regulation of nitric oxide consumption by hypoxic red blood cells (2003)

The homeostasis of nitric oxide (NO) is attained through a balance between its production and consumption. Shifts in NO bioavailability have been linked to a variety of diseases. Although the regulation of NO production has been well documented, its consumption is largely thought to be unregulated. Here, we have demonstrated that under hypoxic conditions, NO accelerates its own consumption by increasing its entry into RBCs. When RBCs were exposed to NO (1:400 NO/heme ratio) under hypoxic conditions to form HbFe(II)NO, the consumption rate of NO increased significantly. This increase in NO consumption converted the bioactivity of serotonin from a vasodilator to a vasoconstrictor in isolated coronary arterioles. We identified HbFe(II)NO as a potential mediator of accelerated NO consumption. Accelerated NO consumption by HbFe(II)NO-bearing RBCs may contribute to hypoxic pulmonary vasoconstriction and the rebound effect seen on termination of NO inhalation therapy. Furthermore, accelerated NO consumption may exacerbate ischemia-mediated vasospasm and nitrate tolerance. Finally, this phenomenon may be an evolved mechanism to stabilize the vasculature in sepsis.
Exponential decay of reconstruction error from binary measurements of\n sparse signals (2014)

Binary measurements arise naturally in a variety of statistical and\nengineering applications. They may be inherent to the problem---e.g., in\ndetermining the relationship between genetics and the presence or absence of a\ndisease---or they may be a result of extreme quantization. In one-bit\ncompressed sensing it has recently been shown that the number of one-bit\nmeasurements required for signal estimation mirrors that of unquantized\ncompressed sensing. Indeed, $s$-sparse signals in $\\mathbb{R}^n$ can be\nestimated (up to normalization) from $\\Omega(s \\log (n/s))$ one-bit\nmeasurements. Nevertheless, controlling the precise accuracy of the error\nestimate remains an open challenge. In this paper, we focus on optimizing the\ndecay of the error as a function of the oversampling factor $\\lambda := m/(s\n\\log(n/s))$, where $m$ is the number of measurements. It is known that the\nerror in reconstructing sparse signals from standard one-bit measurements is\nbounded below by $\\Omega(\\lambda^{-1})$. Without adjusting the measurement\nprocedure, reducing this polynomial error decay rate is impossible. However, we\nshow that an adaptive choice of the thresholds used for quantization may lower\nthe error rate to $e^{-\\Omega(\\lambda)}$. This improves upon guarantees for\nother methods of adaptive thresholding as proposed in Sigma-Delta quantization.\nWe develop a general recursive strategy to achieve this exponential decay and\ntwo specific polynomial-time algorithms which fall into this framework, one\nbased on convex programming and one on hard thresholding. This work is inspired\nby the one-bit compressed sensing model, in which the engineer controls the\nmeasurement procedure. Nevertheless, the principle is extendable to signal\nreconstruction problems in a variety of binary statistical models as well as\nstatistical estimation problems like logistic regression.\n
Surface-Tuned Co3O4 Nanoparticles Dispersed on Nitrogen-Doped Graphene as an Efficient Cathode Electrocatalyst for Mechanical Rechargeable Zinc–Air Battery Application (2015)

The most vital component of the fuel cells and metal-air batteries is the electrocatalyst, which can facilitate the oxygen reduction reaction (ORR) at a significantly reduced overpotential. The present work deals with the development of surface-tuned cobalt oxide (Co3O4) nanoparticles dispersed on nitrogen-doped graphene as a potential ORR electrocatalyst possessing some unique advantages. The thermally reduced nitrogen-doped graphene (NGr) was decorated with three different morphologies of Co3O4 nanoparticles, viz., cubic, blunt edged cubic, and spherical, by using a simple hydrothermal method. We found that the spherical Co3O4 nanoparticle supported NGr catalyst (Co3O4-SP/NGr-24h) has acquired a significant activity makeover to display the ORR activity closely matching with the state-of-the-art Pt supported carbon (PtC) catalyst in alkaline medium. Subsequently, the Co3O4-SP/NGr-24h catalyst has been utilized as the air electrode in a Zn-air battery, which was found to show comparable performance to the system derived from PtC. Co3O4-SP/NGr-24h catalyst has shown several hours of flat discharge profile at the discharge rates of 10, 20, and 50 mA/cm(2) with a specific capacity and energy density of ~590 mAh/g-Zn and ~840 Wh/kg-Zn, respectively, in the primary Zn-air battery system. In conjunction, Co3O4-SP/NGr-24h has outperformed as an air electrode in mechanical rechargeable Zn-air battery as well, which has shown consistent flat discharge profile with minimal voltage loss at a discharge rate of 50 mA/cm(2). The present results, thus demonstrate that the proper combination of the tuned morphology of Co3O4 with NGr will be a promising and inexpensive material for efficient and ecofriendly cathodes for Zn-air batteries.
Phosphatidylinositol 3-kinase-independent synthesis of PtdIns(3,4)P2 by a phosphotransferase (2021)

Abstract Despite their comparatively low abundance, phosphoinositides play a central role in membrane traffic and signalling. PtdIns(3,4,5)P3 and PtdIns(3,4)P2 are uniquely important, as they promote cell growth, survival, and migration. Pathogenic organisms have developed means to subvert phosphoinositide metabolism to promote successful infection and their survival within host organisms. We demonstrate that PtdIns(3,4)P2 is generated in host cells by effectors of the enteropathogenic bacteria Salmonella and Shigella. Pharmacological, gene silencing and heterologous expression experiments revealed that, remarkably, the biosynthesis of PtdIns(3,4)P2 occurs independently of phosphoinositide 3-kinases. Instead, we found that the Salmonella effector SopB, heretofore believed to be a phosphatase, generates PtdIns(3,4)P2 de novo via a phosphotransferase/phosphoisomerase mechanism. Recombinant SopB is capable of generating PtdIns(3,4)P2 from PtdIns(4,5)P2 in a cell-free system. Through a remarkable instance of convergent evolution, bacterial effectors acquired the ability to synthesize 3-phosphorylated phosphoinositides by an ATP- and kinase-independent mechanism, thereby subverting host signaling to gain entry and even provoke oncogenic transformation.
Effect of pregnant sera and a pregnancy-associated metalloproteinase (PAPP-A) on melanoma in vitro and in vivo: Insights into melanoma progression during pregnancy and potential new therapeutic targets. (2014)

9063 Background: At 45/105pregnancies, Malignant Melanoma (MM) is the commonest cancer diagnosed in pregnant women. An aggressive course & poor outcomes are recognised to occur during pregnancy. IGF1 plays an important role in embryogenesis & cancer progression. IGF1 circulates as a complex with IGFBP4, which is cleaved by Pregnancy-Associated Plasma Protein-A (PAPP-A), resulting in release of IGF1. PAPP-A serum levels increase exponentially during pregnancy. Methods: 8 MM cell lines were cultured with pregnant & normal sera. Effect on proliferation (MTS) & invasion/migration (wound healing & matrigel transwell assays) were analysed. PAPP-A expression in human MM & cell lines was analysed by PCR, ELISA & IHC. Transient siRNA knock-down of PAPP-A & downstream gene/protein expression were confirmed. Functional assays were performed after PAPP-A knockdown at 24, 48 & 72hrs. An avian neural crest cell migration assay was used to confirm effects in-vivo. Furthermore, effect of PAPP-A neutralising Ab on cell motility & migration induced by sera was analysed. Results: PAPP-A is widely expressed in MM tumors and cell lines. While the proliferation of MM cells did not change with PAPP-A knockdown, migratory & invasive capacity was significantly decreased (>40% p<0.05). This effect was confirmed in-vivo. The neutralizing Ab attenuated invasion and migration of MM cells, confirming the knockdown results. PAPP-A levels in pregnant sera were 70-fold higher than in control sera. Treatment of MM cells with this serum led to decreased proliferation, but enhanced migration & invasion of MM cells in-vitro. Using an antibody against PAPP-A to evaluate its role in this, we detected a reversion of pregnant serum-induced invasion and migration. Conclusions: Pregnant sera enhances the migratory & invasive behaviour of MM cells in-vitro, which can be effectively attenuated by Ab against PAPP-A. Reduced invasion & migration after PAPP-A knockdown suggests a potential therapeutic target in treatment of MM. This study also gives an indication towards a biological mechanism (PAPP-A) involved in MM progression during pregnancy.
Highly Potent RANTES Analogues either Prevent CCR5-Using Human Immunodeficiency Virus Type 1 Infection In Vivo or Rapidly Select for CXCR4-Using Variants (1999)

The natural ligands for the CCR5 chemokine receptor, macrophage inflammatory protein 1alpha (MIP-1alpha), MIP-1beta, and RANTES (regulated on T-cell activation, normal T-cell expressed and secreted), are known to inhibit human immunodeficiency virus (HIV) entry, and N-terminally modified RANTES analogues are more potent than native RANTES in blocking infection. However, potent CCR5 blocking agents may select for HIV-1 variants that use alternative coreceptors at less than fully inhibitory concentrations. In this study, two N-terminal chemical modifications of RANTES produced by total synthesis, aminooxypentane (AOP)-RANTES[2-68] and N-nonanoyl (NNY)-RANTES[2-68], were tested for their ability to prevent HIV-1 infection and to select for coreceptor switch variants in the human peripheral blood lymphocyte-SCID mouse model. Mice were infected with a CCR5-using HIV-1 isolate that requires only one or two amino acid substitutions to use CXCR4 as a coreceptor. Even though it achieved lower circulating concentrations than AOP-RANTES (75 to 96 pM as opposed to 460 pM under our experimental conditions), NNY-RANTES was more effective in preventing HIV-1 infection. However, in a subset of treated mice, these levels of NNY-RANTES rapidly selected viruses with mutations in the V3 loop of envelope that altered coreceptor usage. These results reinforce the case for using agents that block all significant HIV-1 coreceptors for effective therapy.
Ariadne's thread: Robust turn detection for path back-tracing using the iPhone (2014)

Most systems for pedestrian localization and self-tracking aim to measure the precise position of the walker and match it against a map of the environment. In some cases, a simpler topological description of the path taken may suffice. This is the case for the system described in this paper, which is designed to help a blind person re-trace the route taken inside a building and to walk safely back to the starting point. We present two turn detection algorithms based on hidden Markov models (HMM), which process inertial data collected by an iPhone kept in the walker's front pocket, without the need for a map of the environment. Quantitative results show the robustness of the proposed turn detectors even in the case of drift in the measurements and noticeable body sway during gait.
Enzyme-Modified Buckypaper for Bioelectrocatalysis (2013)

Direct bioelectrocatalysis was demonstrated with pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ–GDH) tethered to a range of carbon nanotube (CNT) materials, as evidenced by the generation of anodic current in the presence of glucose. Physical and electrochemical characterization of CNT paper (buckypaper) reveals marked differences attributed to changes in CNT dimensions, including conductivity, packing density, and electrochemically accessible surface area. By using single-walled CNTs as the electrode material, higher current densities per geometric area and lower electron transfer resistances were achieved. In comparison, electrodes made of oxidized CNTs enhanced in the physical adsorption of PQQ, but displayed voltage drops associated with activation losses. In addition, electrode longevity tests revealed that electrochemical activity was retained for two days but decreased by 50% on the third day. PQQ–GDH enzymatic electrodes show potential application as biological fuel cell anodes and will oxidize a range of mono- and disaccharide substrates.
Randomised clinical trial: efficacy of peginterferon alfa-2a in HBeAg positive chronic hepatitis B patients with lamivudine resistance (2011)

Overall, the response to peginterferon alfa-2a among patients with lamivudine resistance was suboptimal. HBeAg seroconversion rate at week 72 by 48 weeks peginterferon alfa-2a treatment was higher than continuous adefovir therapy. Monitoring HBsAg levels can help to predict response to peginterferon alfa-2a.
Role of direct RhoA‐phospholipase D interaction in mediating adenosine‐induced protection from cardiac ischemia (2003)

Activation of adenosine A1 or A3 receptors protects heart cells from ischemia-induced injury. The A3 receptor signals via RhoA and phospholipase D (PLD) to induce cardioprotection. The objective of the study was to investigate how RhoA activates PLD to achieve the anti-ischemic effect of adenosine A3 receptors. In an established cardiac myocyte model of preconditioning using the cultured chick embryo heart cells, overexpression of the RhoA-noninteracting PLD1 mutant I870R selectively blocked the A3 agonist (Cl-IBMECA, 10 nM)-induced cardioprotection. I870R caused a significantly higher percentage of cardiac cells killed in A3 agonist-treated than in A1 agonist (CCPA, 10 nM)-treated myocytes (ANOVA and posttest comparison, P<0.01). Consistent with its inhibitory effect on the PLD activity, I870R attenuated the Cl-IBMECA-mediated PLD activation. Cl-IBMECA caused a 41 +/- 15% increase in PLD activity in mock-transfected myocytes (P<0.01, paired t test) while having only a slight stimulatory effect on the PLD activity in I870R-transfected cells. To further test the anti-ischemic role of a direct RhoA-PLD1 interaction, atrial cardiac myocytes were rendered null for native adenosine receptors by treatment with irreversible A1 antagonist m-DITC-XAC and were selectively transfected with the human adenosine A1 or A3 receptor cDNA individually or they were cotransfected with cDNAs encoding either receptor plus I870R. I870R preferentially inhibited the human A3 receptor-mediated protection from ischemia. The RhoA-noninteracting PLD1 mutant caused a significantly higher percentage of cardiac cells killed in myocytes cotransfected with the human A3 receptor than in those cells expressing the human A1 receptor (ANOVA and posttest comparison, P<0.01). The present data provided the first demonstration of a novel physiological role for the direct RhoA-PLD1 interaction, that of potent protection from cardiac ischemia. The study further supported the concept that a divergent signaling mechanism mediates the anti-ischemic effect of adenosine A1 and A3 receptors.
Mechanical Deformation of Field-Coupled Materials (2002)

This article describes remarkable similarities in the nonlinear mechanical response of different active/smart materials despite fundamental differences in the underlying mechanisms associated with each material. Active/smart materials (i.e., piezoelectric (PZT-5H), magnetostrictive (Terfenol-D), and shape memory alloys (NiTi)) exhibit strong non-linear mechanical behavior produced by changing non-mechanical internal states such as polarization, magnetization, and phase/twin configuration. In active/smart materials the initial deformation proceeds linearly followed by a jump in strain associated with the transformation of an internal non-mechanical state. After the transformation, the mechanical response returns to linear elastic. Upon unloading, a residual strain is observed which can be recovered with the application of a corresponding external field (i.e., electric, magnetic, or thermal). Due to coupling between applied fields and non-mechanical internal states, mechanical deformation is also a function of applied external fields. At a critical applied field, the residual strain is eliminated, providing repeatable cyclic characteristics that can be used in passive damping applications. Even though different intrinsic processes (i.e., polarization, magnetization, and phase/twin variant composition) govern the deformation of each material, their macroscopic behavior is explained using a unified volume fraction concept. That is, the deformation of piezoelectric material is described in terms of the volume fraction of ferroelectric domains with polarization parallel or orthogonal to the applied load; the deformation of magnetostrictive materials is described in terms of the volume fraction of magnetic domains with magnetization parallel or orthogonal to the applied load; and the deformation of shape memory material is described in terms of the volume fraction of twin variants that are oriented favorably to the applied load. Although the qualitative behavior of each material is similar, the average magnitude of stress required to induce non-linearity varies from ~10 MPa for Terfenol-D to ~65 MPa for PZT-5H to ~300 MPa for NiTi shape memory alloy. It is hypothesized that a composite material made of these materials connected in series would exhibit passive damping over a wide range of applied stress.
Materials for efficient high-flux magnetic bearing actuators (1994)

Magnetic bearings have demonstrated the capability for achieving positioning accuracies at the nanometer level in precision motion control stages. This makes possible the positioning of a wafer in six degrees of freedom with the precision necessary for photolithography. To control the position of an object at the nanometer level, a model of the magnetic bearing actuator force-current-airgap relationship must be accurately obtained. Additionally, to reduce thermal effects the design of the actuator should be optimized to achieve maximum power efficiency and flux density. Optimization of the actuator is accomplished by proper pole face sizing and utilizing a magnetic core material which can be magnetized to the highest flux density with low magnetic loss properties. This paper describes the construction of a magnetic bearing calibration fixture designed for experimental measurement of the actuator force characteristics. The results of a material study that review the force properties of nickel-steel, silicon-steel, and cobalt-vanadium-iron, as they apply to magnetic bearing applications are also presented.
Use of FTA® Sampling Cards for Molecular Detection of Avian Influenza Virus in Wild Birds (2012)

Current avian influenza (AI) virus surveillance programs involving wild birds rely on sample collection methods that require refrigeration or low temperature freezing to maintain sample integrity for virus isolation and/or reverse-transcriptase (RT) PCR. Maintaining the cold chain is critical for the success of these diagnostic assays but is not always possible under field conditions. The aim of this study was to test the utility of Finders Technology Associates (FTA) cards for reliable detection of AI virus from cloacal and oropharyngeal swabs of wild birds. The minimum detectable titer was determined, and the effect of room temperature storage was evaluated experimentally using multiple egg-propagated stock viruses (n = 6). Using real time RT-PCR, we compared results from paired cloacal swab and samples collected on FTA cards from both experimentally infected mallards (Anasplatyrhynchos) and hunter-harvested waterfowl sampled along the Texas Gulf Coast. Based on the laboratory trials, the average minimal detectable viral titer was determined to be 1 x 10(4.7) median embryo infectious dose (EID50)/ml (range: 1 x 10(4.3) to 1 x 10(5.4) EID50/ml), and viral RNA was consistently detectable on the FTA cards for a minimum of 20 days and up to 30 days for most subtypes at room temperature (23 C) storage. Real-time RT-PCR of samples collected using the FTA cards showed fair to good agreement in live birds when compared with both real-time RT-PCR and virus isolation of swabs. AI virus detection rates in samples from several wild bird species were higher when samples were collected using the FTA cards compared with cloacal swabs. These results suggest that FTA cards can be used as an alternative sample collection method when traditional surveillance methods are not possible, especially in avian populations that have historically received limited testing or situations in which field conditions limit the ability to properly store or ship swab samples.
MoS2-capped CuxS nanocrystals: a new heterostructured geometry of transition metal dichalcogenides for broadband optoelectronics (2019)

Heterostructuring of different transition metal dichalcogenides (TMDs) leads to interesting band alignment and performance improvement, and thus enables new routes for the development of materials for next-generation semiconductor electronics.
Secure Mobile Edge Computing in IoT via Collaborative Online Learning (2019)

To accommodate heterogeneous tasks for the Internet of Things (IoT), the emerging mobile edge paradigm extends computing services from the cloud to the edge, but at the same time exposes new challenges on security. In this context, the present paper deals with online security-aware edge computing under jamming attacks. Leveraging online learning tools, novel approaches are developed to cope with adversarial worst-case attacks, and stochastic attacks with random attack strategies. Rather than relying on extra bandwidth and power resources to evade jamming attacks, the resultant algorithms select the most reliable server to offload computing tasks with minimal security concerns. It is analytically established that without any prior information on future jamming and server security risks over a time horizon T, the proposed schemes can achieve O(√T) regret. Information sharing among devices can accelerate the security-aware computing tasks, quantified by what is termed “value of cooperation.” Effectiveness of the proposed schemes is tested on synthetic and real datasets.