Semi-bracketed contextual grammars

Bracketed and fully bracketed contextual grammars were introduced to bring the concept of a tree structure to the strings by associating a pair of parentheses to the adjoined contexts in the derivation. In this paper, we show that these grammars fail to generate all the basic non-context-free languages, thus cannot be a syntactical model for natural languages. To overcome this failure, we introduce a new class of fully bracketed contextual grammars, called the semi-bracketed contextual grammars, where the selectors can also be non-minimally Dyck covered language. We see that the tree structure to the derived strings is still preserved in this variant. when this new grammar is combined with the maximality feature, the generative power of these grammars is increased to the extend of covering the family of context-free languages and some basic non-context-free languages, thus possessing many properties of the so called `MCS formalism'

A new automata for parsing semi-bracketed contextual grammars

Bracketed and fully bracketed contextual grammars were introduced to bring the concept of tree structure to the strings by associating a pair of parentheses to the adjoined contexts in the derivation. But these grammars fail to generate the basic non-context free languages thus unable to provide a syntactical representation to natural languages. To overcome this problem, a new variant called semi-bracketed contextual grammar was introduced recently, where the selectors can also be non-minimally Dyck covered strings. The membership problem for the new variant is left unsolved. In this paper, we propose a parsing algorithm (for non-projected strings) of maximal semi-bracketed contextual grammars. In this process, we introduce a new automaton called k-queue Self Modifying Weighted Automata (k-quSMWA)

Electron paramagnetic resonance evidence that cellular oxygen toxicity is caused by the generation of superoxide and hydroxyl free radicals

AbstractCells require molecular oxygen for the generation of energy through mitochondrial oxidative phosphorylation; however, high concentrations of oxygen are toxic and can cause cell death. A number of different mechanisms have been proposed to cause cellular oxygen toxicity. One hypothesis is that reactive oxygen free radicals may be generated; however free radical generation in hyperoxic cells has never been directly measured and the mechanism of this radical generation is unknown. In order to determine if cellular oxygen toxicity is free radical mediated, we applied electron paramagnetic resonance, EPR, spectroscopy using the spin trap 5,5′-dimethyl-1-pyrroline-N-oxide, DMPO, to measure free radical generation in hyperoxic pulmonary endothelial cells. Cells in air did not give rise to any detectable signal. However, cells exposed to 100% O2 for 30 min exhibited a prominent signal of trapped hydroxyl radical, DMPO-OH, while cell free buffer did not give rise to any detectable radical generation. This cellular radical generation was demonstrated to be derived from the superoxide radical since the observed signal was totally quenched by superoxide dismutase, but not by equal concentrations of the denatured enzyme. It was confirmed that the hydroxyl radical was generated since in the presence of ethanol the CH3·CH(OH) radical was formed. Loss of cell viability as measured by uptake of trypan blue dye was observed paralleling the measured free radical generation. Thus, superoxide and hydroxyl radicals are generated in hyperoxic pulmonary endothelial cells and this appears to be an important mechanism of cellular oxygen toxicity

Design and implementation of automatic water spraying system for solar photovoltaic module

Photovoltaic (PV) cell has a characteristic of decrease in power beyond a certain temperature. This decrease in power is due to a drop in the open circuit cell voltage. This decreases the efficiency of the PV cell. The objective of this research is to increase the efficiency of PV cells by reducing the PV cell temperature and reflection loss. The cell temperature and reflection loss can be reduced by spraying water over the PV cells. On spraying water over the USP36, 24V PV module, the power is found to be increased. The test result shows a 1V to 2V increase in voltage, with an efficiency increment of 1% to 1.27%. The test results of USP37 show the voltage increase of 1.2 V to 2.1 V in the PV module voltage. Due to the increase in voltage, efficiency increment of 1.29% is observed. The efficiency of USP36 with water spraying is more than the efficiency of USP37 without water spraying. In the PV power systems, an average increase in efficiency of 0.5% is observed

NIH Workshop 2018: Towards Minimally Invasive or Noninvasive Approaches to Assess Tissue Oxygenation Pre- and Post-transfusion

Because blood transfusion is one of the most common therapeutic interventions in hospitalized patients, much recent research has focused on improving the storage quality in vitro of donor red blood cells (RBCs) that are then used for transfusion. However, there is a significant need for enhancing our understanding of the efficacy of the transfused RBCs in vivo. To this end, the NIH sponsored a one-and-a-half-day workshop that brought together experts in multiple disciplines relevant to tissue oxygenation (eg, transfusion medicine, critical care medicine, cardiology, neurology, neonatology and pediatrics, bioengineering, biochemistry, and imaging). These individuals presented their latest findings, discussed key challenges, and aimed to identify opportunities for facilitating development of new technologies and/or biomarker panels to assess tissue oxygenation in a minimally-invasive to non-invasive fashion, before and after RBC transfusion

NIH Workshop 2018: Towards Minimally-invasive or Non-invasive Approaches to Assess Tissue Oxygenation Pre- and Post-Transfusion

Because blood transfusion is one of the most common therapeutic interventions in hospitalized patients, much recent research has focused on improving the storage quality in vitro of donor red blood cells (RBCs) that are then used for transfusion. However, there is a significant need for enhancing our understanding of the efficacy of the transfused RBCs in vivo. To this end, the NIH sponsored a one-and-a-half-day workshop that brought together experts in multiple disciplines relevant to tissue oxygenation (e.g., transfusion medicine, critical care medicine, cardiology, neurology, neonatology and pediatrics, bioengineering, biochemistry, and imaging). These individuals presented their latest findings, discussed key challenges, and aimed to construct recommendations for facilitating development of new technologies and/or biomarker panels to assess tissue oxygenation in a minimally-invasive to non-invasive fashion, before and after RBC transfusion. The workshop was structured into four sessions: (1) Global Perspective; (2) Organ Systems; (3) Neonatology; and (4) Emerging Technologies. The first day provided an overview of current approaches in the clinical setting, both from a global perspective, including the use of metabolomics for studying RBCs and tissue perfusion, and from a more focused perspective, including tissue oxygenation assessments in neonates and in specific adult organ systems. The second day focused on emerging technologies, which could be applied pre- and post-RBC transfusion, to assess tissue oxygenation in minimally-invasive or non-invasive ways. Each day concluded with an open-microphone discussion among the speakers and workshop participants. The workshop presentations and ensuing interdisciplinary discussions highlighted the potential of technologies to combine global “omics” signatures with additional measures (e.g., thenar eminence measurements or various imaging methods) to predict which patients could potentially benefit from a RBC transfusion and whether the ensuing RBC transfusion was effective. The discussions highlighted the need for collaborations across the various disciplines represented at the meeting to leverage existing technologies and to develop novel approaches for assessing RBC transfusion efficacy in various clinical settings. Although the Workshop took place in April, 2018, the concepts described and the ensuing discussions were, perhaps, even more relevant in April, 2020, at the time of writing this manuscript, during the explosive growth of the COVID-19 pandemic in the United States. Thus, issues relating to maintaining and improving tissue oxygenation and perfusion are especially pertinent because of the extensive pulmonary damage resulting from SARS-CoV-2 infection [1], compromises in perfusion caused by thrombotic-embolic phenomena [2], and damage to circulating RBCs, potentially compromising their oxygen-carrying capacity [3]. The severe end organ effects of SARS-CoV-2 infection mandate even more urgency for improving our understanding of tissue perfusion and oxygenation, improve methods for measuring and monitoring them, and develop novel ways of enhancing them

HIF-transcribed p53 chaperones HIF-1α

Chronic hypoxia is associated with a variety of physiological conditions such as rheumatoid arthritis, ischemia/reperfusion injury, stroke, diabetic vasculopathy, epilepsy and cancer. At the molecular level, hypoxia manifests its effects via activation of HIF-dependent transcription. On the other hand, an important transcription factor p53, which controls a myriad of biological functions, is rendered transcriptionally inactive under hypoxic conditions. p53 and HIF-1α are known to share a mysterious relationship and play an ambiguous role in the regulation of hypoxia-induced cellular changes. Here we demonstrate a novel pathway where HIF-1α transcriptionally upregulates both WT and MT p53 by binding to five response elements in p53 promoter. In hypoxic cells, this HIF-1α-induced p53 is transcriptionally inefficient but is abundantly available for protein-protein interactions. Further, both WT and MT p53 proteins bind and chaperone HIF-1α to stabilize its binding at its downstream DNA response elements. This p53-induced chaperoning of HIF-1α increases synthesis of HIF-regulated genes and thus the efficiency of hypoxia-induced molecular changes. This basic biology finding has important implications not only in the design of anti-cancer strategies but also for other physiological conditions where hypoxia results in disease manifestation

Hide The Modulus: A Secure Non-Interactive Fully Verifiable Delegation Scheme for Modular Exponentiations via CRT

Security protocols using public-key cryptography often requires large number of costly modular exponentiations (MEs). With the proliferation of resource-constrained (mobile) devices and advancements in cloud computing, delegation of such expensive computations to powerful server providers has gained lots of attention. In this paper, we address the problem of verifiably secure delegation of MEs using two servers, where at most one of which is assumed to be malicious (the OMTUP-model). We first show verifiability issues of two recent schemes: We show that a scheme from IndoCrypt 2016 does not offer full verifiability, and that a scheme for $n$ simultaneous MEs from AsiaCCS 2016 is verifiable only with a probability $0.5909$ instead of the author\u27s claim with a probability $0.9955$ for $n=10$. Then, we propose the first non-interactive fully verifiable secure delegation scheme by hiding the modulus via Chinese Remainder Theorem (CRT). Our scheme improves also the computational efficiency of the previous schemes considerably. Hence, we provide a lightweight delegation enabling weak clients to securely and verifiably delegate MEs without any expensive local computation (neither online nor offline). The proposed scheme is highly useful for devices having (a) only ultra-lightweight memory, and (b) limited computational power (e.g. sensor nodes, RFID tags)

Positional Signaling and Expression of ENHANCER OF TRY AND CPC1 Are Tuned to Increase Root Hair Density in Response Phosphate Deficiency in Arabidopsis thaliana

Phosphate (Pi) deficiency induces a multitude of responses aimed at improving the acquisition of Pi, including an increased density of root hairs. To understand the mechanisms involved in Pi deficiency-induced alterations of the root hair phenotype in Arabidopsis (Arabidopsis thaliana), we analyzed the patterning and length of root epidermal cells under control and Pi-deficient conditions in wild-type plants and in four mutants defective in the expression of master regulators of cell fate, CAPRICE (CPC), ENHANCER OF TRY AND CPC 1 (ETC1), WEREWOLF (WER) and SCRAMBLED (SCM). From this analysis we deduced that the longitudinal cell length of root epidermal cells is dependent on the correct perception of a positional signal (‘cortical bias’) in both control and Pi-deficient plants; mutants defective in the receptor of the signal, SCM, produced short cells characteristic of root hair-forming cells (trichoblasts). Simulating the effect of cortical bias on the time-evolving probability of cell fate supports a scenario in which a compromised positional signal delays the time point at which non-hair cells opt out the default trichoblast pathway, resulting in short, trichoblast-like non-hair cells. Collectively, our data show that Pi-deficient plants increase root hair density by the formation of shorter cells, resulting in a higher frequency of hairs per unit root length, and additional trichoblast cell fate assignment via increased expression of ETC1