gebhart/patrepeval huggingface dataset:
Bandwidth Enhancement of a Horizontally Polarized Omnidirectional Antenna by Adding Parasitic Strips (2016)

A horizontally polarized omnidirectional antenna with enhanced impedance bandwidth is presented in this letter. The proposed antenna consists of a feeding network, four printed dipole elements with etched slots, parasitic strips, and director elements. Four identically curved and printed dipole elements are placed in a square array and fed by a feeding network with uniform magnitude and phase; thus, the proposed antenna can achieve an omnidirectional radiation. To enhance the impedance bandwidth, parasitic strips and etched slots are introduced to produce additional lower and upper resonant frequencies, respectively. By utilizing four director elements, the gain variation in the horizontal plane can be improved, especially for the upper frequency band. With the structure, a reduced size of 0.63 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> × 0.63 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> × 0.01 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> ( λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> is the free-space wavelength at the lowest frequency) is obtained. The proposed antenna is designed and fabricated. Measurement results reveal that the proposed antenna can provide an impedance bandwidth of 84.2% (1.58-3.88 GHz). Additionally, the gain variation in the horizontal plane is less than 1.5 dB over the frequency band 1.58-3.50 GHz, and increased to 2.2 dB at 3.80 GHz. Within the impedance bandwidth, the cross-polarization level is less than -23 dB in the horizontal plane.
Mechanisms of the oxygen reduction reaction on B- and/or N-doped carbon nanomaterials with curvature and edge effects (2017)

Despite recent increased research interest in hetero-atom (B and/or N) doping effects on the oxygen reduction reaction (ORR) performance of carbon nanomaterials, microscopic understanding of active catalytic sites and effects of B and/or N doping has not been conclusively reached. Here, through comparative first-principles simulations between BN codoping and isolated B or N doping in both graphene nanoribbons (GNRs) and carbon nanotubes (CNTs), we not only identify active sites in these doped carbon nanomaterials, but elucidate the underlying mechanism of ORR processes. While the distortion of C-C bonds in CNTs leads to strong binding of O<sub>2</sub>, spin density distribution along the edges plays a key role in enhancing the adsorption strength of O<sub>2</sub> on GNRs. The effective adsorption of O<sub>2</sub> facilitates the following elementary reduction reactions. Based on thermodynamic analyses, O<sub>2</sub> adsorption as well as the electron and proton transfer to O atom are identified as key rate-determining steps. For CNTs, a good linear scaling is found between the adsorption energies of key intermediate products and that of atomic O, and thus the latter serves as a good descriptor for ORR activities. Further, N-doped high-quality CNTs are shown to exhibit best performance. For GNRs, due to edge effects, the linear relationship is broken, which promotes the catalytic activities in the BN codoping case. These findings resolve the long-standing controversy on the synergetic effects of B and N codoping, which deepens our understanding of the reaction mechanism. This work might further facilitate the optimization of the doping strategies for high-efficiency carbon-based ORR catalysts.
500°C operation of a GaN/SiC heterojunction bipolar transistor (2002)

Silicon Carbide has been proposed as a preferred material for high-power, high temperature semiconductor devices, primarily because of its large energy-bandgap and high thermal conductivity. Heterojunction bipolar transistors with a GaN wide bandgap emitter and SiC base and collector region have recently been demonstrated to have very high DC current gain (>100,000) and have been operated up to 260/spl deg/C. We present the first operation of a semiconductor bipolar transistor at a temperature of 500/spl deg/C with a current gain greater than 100. The GaN/SiC n-p-n HBT's common base I-V characteristics, current gain versus emitter current curves, and Gummel plots were obtained at temperatures ranging from 25/spl deg/C to 535/spl deg/C. The I-V characteristics showed little change over this temperature range, except for an increase in leakage current with increasing temperature. Only common base characteristics were obtained due to the high gain of the devices and the leakage current between base and collector. The high temperature of operation and the large gain even at elevated temperatures indicate the extraordinary potential of these devices for high-temperature and high-power operation.
Experimental study on the hemostatic activity of the Tibetan medicinal herb <i>Lamiophlomis rotata</i> (2008)

The blood hemostatic activity of the Tibetan medicinal herb Lamiophlomis rotata was evaluated in BALB/c mice and Wistar rats. L. rotata aqueous extract (LRAE) was given to mice at concentrations of 0.5, 1.0, 2.0 g/kg body weight and 0.75, 1.5, 3.0 g/kg to rats. The hemostatic activity of LRAE was estimated by changes in bleeding time (BT), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and fibrinogen (FIB). At the same time hepatic function and blood fat indexes including AST, ALT, Alb, Chol and LDL-C were measured also. The results showed that an appropriate level of LRAE could shorten the BT and TT values and increase the Alb level paralleling that of FIB. However, the shortening of the PT was only possible by a high and long administration of LRAE, and no change in APTT was observed. On the other hand, LRAE showed some effects in improving the liver function and reducing blood lipids by decreasing the levels of AST, ALT, Chol and LDL-C. All these changes had a significant dose-effect and time-effect relationship. These results confirm the hemostatic and thromboplastic effects of L. rotata and these effects might be implemented by improving the synthetic function of the liver.
Dissecting the Immune Landscape of Acute Myeloid Leukemia (2018)

Acute myeloid leukemia (AML) is a molecularly heterogeneous hematological malignancy with variable response to treatment. Recurring cytogenetic abnormalities and molecular lesions identify AML patient subgroups with different survival probabilities; however, 50⁻70% of AML cases harbor either normal or risk-indeterminate karyotypes. The discovery of better biomarkers of clinical success and failure is therefore necessary to inform tailored therapeutic decisions. Harnessing the immune system against cancer with programmed death-1 (PD-1)-directed immune checkpoint blockade (ICB) and other immunotherapy agents is an effective therapeutic option for several advanced malignancies. However, durable responses have been observed in only a minority of patients, highlighting the need to gain insights into the molecular features that predict response and to also develop more effective and rational combination therapies that address mechanisms of immune evasion and resistance. We will review the state of knowledge of the immune landscape of AML and identify the broad opportunity to further explore this incompletely characterized space. Multiplexed, spatially-resolved immunohistochemistry, flow cytometry/mass cytometry, proteomic and transcriptomic approaches are advancing our understanding of the complexity of AML-immune interactions and are expected to support the design and expedite the delivery of personalized immunotherapy clinical trials.
Prostaglandin E2 (PGE2) promotes proliferation and invasion by enhancing SUMO-1 activity via EP4 receptor in endometrial cancer (2016)

Prostaglandin E2 (PGE2), a derivative of arachidonic acid, has been identified as a tumorigenic factor in many cancers in recent studies. Prostaglandin E synthase 2 (PTGES2) is an enzyme that in humans is encoded by the PTGES2 gene located on chromosome 9, and it synthesizes PGE2 in human cells. In our study, we selected 119 samples from endometrial cancer patients, with 50 normal endometrium tissue samples as controls, in which we examined the expression of PTGES2. Both immunohistochemistry (IHC) and Western blot analyses demonstrated that synthase PTGES2, which is required for PGE2 synthesis, was highly expressed in endometrium cancer tissues compared with normal endometrium. Stable PTGES2-shRNA transfectants were generated in Ishikawa and Hec-1B endometrial cancer cell lines, and transfection efficiencies were confirmed by RT-PCR and Western blot analyses. We found that PGE2 promoted proliferation and invasion of cells in Ishikawa and Hec-1B cells by cell counting kit-8 tests (CCK8) and transwell assays, respectively. PGE2 stimulation enhanced the expression of SUMO-1, via PGE2 receptor subtype 4 (EP4). Further analysis implicated the Wnt/β-catenin signaling pathway function as the major mediator of EP4 and SUMO-1. The increase in SUMO-1 activity prompted the SUMOlyation of target proteins which may be involved in proliferation and invasion. These findings suggest SUMO-1 and EP4 as two potential targets for new therapeutic or prevention strategies for endometrial cancers.
IDH1 mutation of gliomas with long-term survival analysis (2012)

A recurrent mutation affecting codon 132 of the isocitrate dehydrogenase 1 (IDH1) gene has been found in ~5% of primary glioblastomas (GBMs), but in >70% of secondary GBMs or oligodendroglial and astrocytic tumors. We investigated IDH1 mutations in a series of 134 brain tumors to determine the prevalence and prognostic impact of IDH1 mutations. We also examined the correlations among histology, p53 and PTEN immunoexpression, MGMT methylation status, 1p 19q co-deletion and EGFR gene amplification. The 134 brain tumors included 41 low-grade oligodendrogliomas (LOs), 47 anaplastic oligodendrogliomas (AOs) and 46 primary GBMs. Data showed that 53.7% (72/134) of cases showed mutations affecting codon 132 of IDH1, including 73.2% of LOs, 82.9% of AOs and three primary GBMs (6.5%). All IDH1 mutations were Arg132His. In a survival analysis, patients with IDH1 mutations had better survival compared to those with wild-type IDH1 (p<0.05) in LOs and AOs, but not in primary GBMs (p=0.587). In addition, in patients with both IDH1 mutation and MGMT methylation, p53 overexpression was a significant poor prognostic factor both in LOs and AOs. However, IDH1 mutation was not correlated with common genetic profiles that affect patient prognosis, including MGMT methylation, 1p 19q co-deletion, PTEN loss and EGFR amplification in LOs, AOs and GBMs. From our results, IDH1 mutation was an independent positive prognostic factor in LOs and AOs, especially in the absence of p53 overexpression.
Refractive-index profile of an optical fiber: its measurement by the scattering-pattern method (1976)

This paper describes a new method (the scattering-pattern method) for determining the refractive-index profile in an optical fiber from its scattering pattern for a normally incident laser beam. The proposed method is applicable to an arbitrary profile and is nondestructive. The spatial resolution is high, and the accuracy is good when the fiber diameter and the refractive-index variation are relatively small. The drawback is that a large number of data are required; however, this difficulty has been overcome by using the automated measuring system described in this paper. The profile obtained shows good agreement with design data.
Boosting Verification by Automatic Tuning of Decision Procedures (2007)

Parameterized heuristics abound in computer aided design and verification, and manual tuning of the respective parameters is difficult and time-consuming. Very recent results from the artificial intelligence (AI) community suggest that this tuning process can be automated, and that doing so can lead to significant performance improvements; furthermore, automated parameter optimization can provide valuable guidance during the development of heuristic algorithms. In this paper, we study how such an AI approach can improve a state-of-the-art SAT solver for large, real-world bounded model-checking and software verification instances. The resulting, automatically-derived parameter settings yielded runtimes on average 4.5 times faster on bounded model checking instances and 500 times faster on software verification problems than extensive hand-tuning of the decision procedure. Furthermore, the availability of automatic tuning influenced the design of the solver, and the automatically-derived parameter settings provided a deeper insight into the properties of problem instances.
Control of flowering time by <i>FLC</i> orthologues in <i>Brassica napus</i> (2001)

FLOWERING LOCUS C (FLC) in Arabidopsis encodes a dosage dependent repressor of flowering. We isolated five FLC-related sequences from Brassica napus (BnFLC1-5). Expression of each of the five sequences in Arabidopsis delayed flowering significantly, with the delay in flowering time ranging from 3 weeks to more than 7 months, relative to the flowering time of 3 weeks in untransformed Ler. In the reciprocal experiment, expression of Arabidopsis FLC (AtFLC) in an early flowering B. napus cultivar delayed flowering by 2-6 weeks, confirming the requirement of this gene for floral repression. In B. napus, we show that late flowering and responsiveness to vernalization correlate with the level of BnFLC mRNA expression. The different BnFLC genes show differential expression in leaves, stems and shoot tips, but expression is not detectable in roots. Vernalization dramatically reduces the level of BnFLC transcript and restores early flowering in the winter cultivar Colombus. We conclude that BnFLC genes confer winter requirement in B. napus and account for the major vernalization-responsive flowering time differences in the different cultivars of B. napus in a manner analogous to that of AtFLC in Arabidopsis ecotypes.
Amino acid changes in the fourth conserved region of human immunodeficiency virus type 2 strain HIV-2ROD envelope glycoprotein modulate fusion (1993)

The fourth conserved region (C4) of human immunodeficiency virus type 1 (HIV-1) surface glycoprotein has been shown to participate in CD4 binding and to influence viral tropism (A. Cordonnier, L. Montagnier, and M. Emerman, Nature [London] 340:571-574, 1989). To define the role of the corresponding region of HIV-2, we introduce single amino acid changes into the C4 sequence of HIV-2ROD. The effects of these mutations on glycoprotein function and on virus infectivity have been examined. We have shown that the tryptophan residue at position 428 is necessary primarily for CD4 binding. The isoleucine residue at position 421 is necessary for the establishment of productive infection in the promonocytic cell line U937, while it is dispensable to some extent for infection of primary T lymphocytes or the lymphocytic cell line SUP-T1. This replication defect correlated with the failure of the Ile-421-to-Thr (Ile-421-->Thr) mutant glycoprotein to form syncytia in U937 cells. DNA analysis of revertant viruses revealed that a strong selective pressure was exerted on residue 421 of the surface glycoprotein to allow HIV-2 infection of U937 cells. These results demonstrate that this region of HIV-2 plays an important role in determining fusion efficiency in a cell-dependent manner and consequently can influence viral tropism.
Purification and properties of uridine diphosphate galactose-4-epimerase from yeast (1968)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPurification and properties of uridine diphosphate galactose-4-epimerase from yeastRobert A. Darrow and Robert. RodstromCite this: Biochemistry 1968, 7, 5, 1645–1654Publication Date (Print):May 1, 1968Publication History Published online1 May 2002Published inissue 1 May 1968https://pubs.acs.org/doi/10.1021/bi00845a005https://doi.org/10.1021/bi00845a005research-articleACS PublicationsRequest reuse permissionsArticle Views84Altmetric-Citations82LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
An 8.5mW 5GS/s 6b flash ADC with dynamic offset calibration in 32nm CMOS SOI (2013)

This paper describes a 5GS/s 6bit flash ADC fabricated in a 32nm CMOS SOI. The randomness of process mismatch is exploited to compensate for dynamic offset errors of comparators that occur during high speed operation. Utilizing the proposed calibration, comparators are designed with near-minimum size transistors and built-in reference levels. The ADC achieves an SNDR of 30.9dB at Nyquist and consumes 8.5mW with an FoM of 59.4fJ/conv-step.
Enzymatic synthesis of oligodeoxyribonucleotides of defined sequence. Polynucleotide phosphorylase catalysed synthesis using pyrimidine analog-containing deoxyribonucleoside 5′-diphosphates (1978)

The E. coli polynucleotide phosphorylase-catalysed reaction of the deoxynucleoside 5'-diphosphates of 5-methyldeoxycytidine, N4-hydroxydeoxycytidine, deoxyuridine and 5-mercurideoxyuridine with the primers d(pT-T-A-G) and d(pT-T-T-T-T-T) have been studied under conditions where the primer is extended, predominantly, by one or two nucleotide residues. In experiments with 5-mercurideoxyuridine 5'-diphosphate, no 5-mercurideoxy-uridine-containing oligonucleotides were produced. The other three nucleotide analogs were found to be good substrates for E. coli PNPase and the conditions established for synthesis with these analogs will allow the construction of a number of biologically useful types of oligodeoxyribonucleotide.
Enhanced responsiveness of <i>Ghsr</i> <sup>Q343X</sup> rats to ghrelin results in enhanced adiposity without increased appetite (2016)

The ability of the gut hormone ghrelin to promote positive energy balance is mediated by the growth hormone secretagogue receptor (GHSR). GHSR is a G protein-coupled receptor (GPCR) that is found centrally and peripherally and that can signal in a ligand-independent manner basally or when heterodimerized with other GPCRs. However, current Ghsr knockout models cannot dissect ghrelin-dependent and ghrelin-independent signaling, precluding assessment of the physiological importance of these signaling pathways. An animal model carrying a Ghsr mutation that preserves GHSR cell surface abundance, but selectively alters GHSR signaling, would be a useful tool to decipher GHSR signaling in vivo. We used rats with the Ghsr(Q343X) mutation (Ghsr(M/M)), which is predicted to delete the distal part of the GHSR carboxyl-terminal tail, a domain critical for the signal termination processes of receptor internalization and β-arrestin recruitment. In cells, the GHSR-Q343X mutant showed enhanced ligand-induced G protein-dependent signaling and blunted activity of processes involved in GPCR signal termination. Ghsr(M/M)rats displayed enhanced responses to submaximal doses of ghrelin or GHSR agonist. Moreover, Ghsr(M/M)rats had a more stable body weight under caloric restriction, a condition that increases endogenous ghrelin tone, whereas under standard housing conditions,Ghsr(M/M)rats showed increased body weight and adiposity and reduced glucose tolerance. Overall, our data stress the physiological role of the distal domain of GHSR carboxyl terminus as a suppressor of ghrelin sensitivity, and we propose using the Ghsr(M/M)rat as a physiological model of gain of function in Ghsr to identify treatments for obesity-related conditions.
Lewis Acid Catalyzed Intramolecular [3+2] Cross‐Cycloaddition of Donor–Acceptor Cyclopropanes with Carbonyls: A General Strategy for the Construction of Acetal[<i>n</i>.2.1] Skeletons (2011)

Build a bridge: The first catalytic intramolecular [3+2] cycloaddition of monodonor-monoacceptor cyclopropanes (see scheme) provides a general and efficient strategy for construction of structurally diverse acetal[n.2.1] and 1,4-dioxygen-substituted cyclic skeletons, which are widely distributed in biologically important natural products.
Host-parasite coevolutionary arms races give way to fluctuating selection (2011)

Host-parasite coevolution is a key driver of biological diversity and parasite virulence, but its effects depend on the nature of coevolutionary dynamics over time. We used phenotypic data from coevolving populations of the bacterium Pseudomonas fluorescens SBW25 and parasitic phage SBW25Φ2, and genetic data from the phage tail fibre gene (implicated in infectivity evolution) to show that arms race dynamics, typical of short-term studies, decelerate over time. We attribute this effect to increasing costs of generalism for phages and bacteria with increasing infectivity and resistance. By contrast, fluctuating selection on individual host and parasite genotypes was maintained over time, becoming increasingly important for the phenotypic properties of parasite and host populations. Given that costs of generalism are reported for many other systems, arms races may generally give way to fluctuating selection in antagonistically coevolving populations.
NASA Puffin Electric Tailsitter VTOL Concept (2010)

Electric propulsion offers dramatic new vehicle mission capabilities, not possible with turbine or reciprocating engines; including high reliability and efficiency, low engine weight and maintenance, low cooling drag and volume required, very low noise and vibration, and zero emissions. The only penalizing characteristic of electric propulsion is the current energy storage technology level, which is set to triple over the next 5-10 years through huge new investments in this field. Most importantly, electric propulsion offers incredible new degrees of freedom in aircraft system integration to achieve unprecedented levels of aerodynamic, propulsive, control, and structural synergistic coupling. A unique characteristic of electric propulsion is that the technology is nearly scale-free, permitting small motors to be parallelized for fail-safe redundancy, or distributed across the airframe for tightly coupled interdisciplinary functionality without significant impacts in motor-controller efficiency or specific weight. Maximizing the potential benefit of electric propulsion is dependent on applying this technology to synergistic mission concepts. The vehicle missions with the most benefit include those which constrain environmental impact (or limit noise, exhaust, or emission signatures) are short range, or where large differences exist in the propulsion system sizing between takeoff and cruise conditions. Electric propulsion offers the following unique capabilities that other propulsion systems can t provide for short range Vertical Takeoff and Landing (VTOL) aircraft; elimination of engine noise and emissions, drastic reduction in engine cooling and radiated heat, drastic reduction in vehicle vibration levels, drastic improvement in reliability and operating costs, variable speed output at full power, for improved cruise efficiency at low tip-speed, elimination of high/hot sizing penalty, and reduction of engine-out penalties.