gebhart/patrepeval huggingface dataset:
Large Cages of Zeolitic Imidazolate Frameworks (2022)

The design and synthesis of permanently porous materials with extended cage structures is a long-standing challenge in chemistry. In this Account, we highlight the unique role of zeolitic imidazolate frameworks (ZIFs), a class of framework materials built from tetrahedral nodes connected through imidazolate linkers, in meeting this challenge and illustrate specific features that set ZIFs apart from other porous materials. The structures of ZIFs are characteristic of a variety of large, zeolite-like cages that are covalently connected with neighboring cages and fused in three-dimensional space. In contrast to molecular cages, the fusion of cages results in extraordinary architectural and chemical stability for the passage of gases and molecules through cages and for carrying out chemical reactions within these cages while keeping the cages intact. The combination of the advantages from both cage chemistry and extended structures allows uniquely interconnected yet compartmentalized void spaces inside ZIF solids, rendering their wide range of applications in catalysis, gas storage, and gas separation.While the field of ZIFs has seen rapid development over the past decade, with hundreds of ZIF structures built from dozens of different cages of varying composition, size, and shapes reported, rational approaches to their design are largely unknown. In this Account, we summarize a vast number of cages formed in reported ZIFs and then review how the thermodynamic factors and traditional guest-templating strategies from zeolites influence the formation of cages. We highlight how the link-link interactions perform in the ZIF formation mechanism and serve as a means to target the formation of frameworks containing cages of specific sizes with structures exhibiting a level of complexity as yet unachieved in discrete coordination cages. For example, the giant <i>ucb</i> cage features a dimension of 46 Å and the complex <i>moz</i> cage is constructed from as many as 660 components.With the finding of these large and complex cages in ZIFs, we envision that the collection of cage structures will further be diversified by a mixed-linker approach utilizing a more complex combination of link-link interactions or by creating multivariant (MTV) systems that have been realized in other framework materials yet not widely employed in ZIFs. The more complicated cage structures can provide extra variations in chemical environments, and in addition to that, MTV systems can generate inhomogeneity inside each type of cage structure. The fused cages at such complexity that are difficult to be realized in solution environments will potentially enable more complex materials for smart applications.
Conversion of .alpha.1-Antichymotrypsin into a Human Neutrophil Elastase Inhibitor: Demonstration of Variants with Different Association Rate Constants, Stoichiometries of Inhibition, and Complex Stabilities (1994)

Despite the homology with alpha 1-protease inhibitor (alpha 1PI), wild-type antichymotrypsin (ACT) is a substrate for HNE rather than an inhibitor of the enzyme. In order to investigate the nature of the specificity between serpins and serine proteases, the reactions of human neutrophil elastase (HNE) with wild-type recombinant ACT and recombinant variants of ACT were studied. ACT variants were generated where (1) the primary interaction site, the P1 position, was replaced with the P1 residue of alpha 1PI, (2) the residues corresponding to P3-P3' were replaced with those of alpha 1PI, and (3) the residues corresponding to the canonical recognition sequence as well as flanking residues encompassing the exposed reactive loop of the inhibitor were replaced with the corresponding residues of alpha 1PI. Each variant was analyzed to determine the effect of the replacements on reactions with human neutrophil elastase and chymotrypsin with regard to (1) the second-order rate constant for enzyme-serpin complex formation, (2) the number of moles of serpin required to completely inhibit 1 mol of enzyme (the stoichiometry of inhibition, SI), and (3) the stability of the enzyme-serpin complex. Replacing Leu with Met in the P1 position (rACT-L358M) was sufficient to convert rACT into an inhibitor of HNE with an apparent second-order rate constant (k'/[I]) of 4 x 10(4) M-1 s-1 and an SI of 5. The high SI was due to a concurrent hydrolytic reaction at sites in the reactive loop.(ABSTRACT TRUNCATED AT 250 WORDS)
The progress update of relaxor piezoelectric single crystals (2009)

A series of relaxor piezoelectric single crystals, including lead magnesium niobate-lead titanate (PMN-PT) and pure and manganese-doped lead indium niobate-lead magnesium niobate-lead titanate (PIN-PMN-PT and Mn: PIN-PMN-PT), have been developed by a modified Bridgman crystal growth process. These single crystals have been grown along both <001> and <110> with diameters up to 75 mm. PIN-PMN-PT possesses the similar electromechanical properties to PMN-PT, while rhombohedral-to-tetragonal phase transition temperature (T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rt</sub> ) and coercive field (E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> ) increased to higher than 120°C and 4.5kV/cm, respectively. By doping with Mn, mechanical quality factor (Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</sub> ) increased above 700 in <001>-poled longitudinal mode without compromising electromechanical coupling (k <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">33</sub> ), T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rt</sub> and E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> . This work demonstrated that by composition modification, the electromechanical properties of PMN-PT based crystals can be stabilized with respect to operating temperature and electric field.
Antibody-mediated immunotherapy against chronic hepatitis B virus infection (2017)

The currently available drugs to treat hepatitis B virus (HBV) infection include interferons and nucleos(t)ide analogs, which can only induce disease remission and are inefficient for the functional cure of patients with chronic HBV infection (CHB). Since high titers of circulating hepatitis B surface antigen (HBsAg) may be essential to exhaust the host anti-HBV immune response and they cannot be significantly reduced by current drugs, new antiviral strategies aiming to suppress serum hepatitis B surface antigen (HBsAg) could help restore virus-specific immune responses and promote the eradication of the virus. As an alternative strategy, immunotherapy with HBsAg-specific antibodies has shown some direct HBsAg suppression effects in several preclinical and clinical trial studies. However, most described previously HBsAg-specific antibodies only had very short-term HBsAg suppression effects in CHB patients and animal models mimicking persistent HBV infection. More-potent antibodies with long-lasting HBsAg clearance effects are required for the development of the clinical application of antibody-mediated immunotherapy for CHB treatment. Our recent study described a novel mAb E6F6 that targets a unique epitope on HBsAg. It could durably suppress the levels of HBsAg and HBV DNA via Fcγ receptor-dependent phagocytosis in vivo. In this commentary, we summarize the current research progress, including the therapeutic roles and mechanisms of antibody-mediated HBV clearance as well as the epitope-determined therapeutic potency of the antibody. These insights may provide some clues and guidance to facilitate the development of therapeutic antibodies against persistent viral infection.
Quality-aware selection of quality factor and scaling parameters in JPEG image transcoding (2009)

Reducing the file size of a JPEG image to meet bandwidth or terminal constraints is a common transcoding operation. The reduction can be achieved by reducing either the quality factor (QF) or the resolution, or both. In this paper, we analyze the impact of QF and scaling parameter choices on the quality of the resulting images, as measured by a quality metric such as the structural similarity index (SSIM). We propose a quality-aware transcoding system which considers the quality of transcoded images when QF and scaling are selected jointly. Its goal is to select QF and scaling parameters that maximize the user experience under a given viewing condition, as measured by the chosen quality metric.
A Structural Variation for MurB:  X-ray Crystal Structure of <i>Staphylococcus aureus </i>UDP-<i>N</i>-Acetylenolpyruvylglucosamine Reductase (MurB) (2001)

The X-ray crystal structure of the substrate free form of Staphylococcus aureus UDP-N-acetylenolpyruvylglucosamine reductase (MurB) has been solved to 2.3 A resolution with an R-factor of 20.3% and a free R-factor of 22.3%. While the overall fold of the S. aureus enzyme is similar to that of the homologous Escherichia coli MurB X-ray crystal structure, notable distinctions between the S. aureus and E. coli MurB protein structures occur in residues involved in substrate binding. Analysis of available MurB sequences from other bacteria suggest that the S. aureus MurB structure is representative of a distinct structural class of UDP-N-acetylenolpyruvylglucosamine reductases including Bacillus subtilis and Helicobacter pylori that are characterized by a modified mechanism for substrate binding.
Faceting control in core-shell GaN micropillars using selective epitaxy (2014)

We report on the fabrication of large-area, vertically aligned GaN epitaxial core-shell micropillar arrays. The two-step process consists of inductively coupled plasma (ICP) etching of lithographically patterned GaN-on-Si substrate to produce an array of micropillars followed by selective growth of GaN shells over these pillars using Hydride Vapor Phase Epitaxy (HVPE). The most significant aspect of the study is the demonstration of the sidewall facet control in the shells, ranging from {11̄01} semi-polar to {11̄00} non-polar planes, by employing a post-ICP chemical etch and by tuning the HVPE growth temperature. Room-temperature photoluminescence, cathodoluminescence, and Raman scattering measurements reveal substantial reduction of parasitic yellow luminescence as well as strain-relaxation in the core-shell structures. In addition, X-ray diffraction indicates improved crystal quality after the shell formation. This study demonstrates the feasibility of selective epitaxy on micro-/nano- engineered templates for realizing high-quality GaN-on-Si devices.
Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activation polypeptide (PACAP) protect mice from lethal endotoxemia through the inhibition of TNF-alpha and IL-6. (1999)

The neuropeptides vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) down-regulate cytokine production. Because human septic shock involves excessive cytokine production, the effect of VIP/PACAP was investigated in a high endotoxemia murine model. Both peptides protect against endotoxin-induced lethality and prevent septic shock-associated histopathological alterations. VIP/PACAP reduce serum and peritoneal TNF-alpha and IL-6, suggesting that the protective effect is exerted by inhibiting the production of endogenous TNF-alpha/IL-6. Consistent with this mechanism, VIP does not protect against septic shock induced by exogenous TNF-alpha. The immunomodulatory role of VIP in vivo is supported by the appearance of high levels of VIP in serum and peritoneal fluid following LPS administration. Thus, the neuropeptides VIP/PACAP protect from the lethal effect of high endotoxemia, presumably by down-regulating TNF-alpha and IL-6 production, and may offer an alternative in the treatment of human septic shock syndrome.
SYNTHESIS AND CHARACTERIZATION OF MoS2 –GRAPENE OXIDE ON Ni-Co-MnO2 NANOFIBER LIKE BINARY COMPOSITE FOR NICKEL FOAM BASED FLEXIBLE ELECTRODE FABRICATION (2020)

Nickel/cobalt co-doped porous manganese oxide(MnOx) is fabricated by feasible nonionic surfactant route followed by precipitation heat treatment method. The as prepared metal ion modified manganese oxide further impregnated via reducing graphene oxide and MoS2 nanoparticles by ultra-sonication assisted deposition method. The as prepared binary nanocomposite is characterized by XRD and HR-TEM for crystalline phase formation analysis and structure morphology determination. Binder free flexible electrode fabrication on nickel foam using MoS2/graphene modified Ni-Co-MnO2 have also been studied and it shows higher super capacitor performance like 1190 F/g in aqueous acidic conditions.
Recent advances in non-precious metal catalysis for oxygen-reduction reaction in polymer electrolyte fuelcells (2010)

Hydrogen produced from water and renewable energy could fuel a large fleet of proton-exchange-fuel-cell vehicles in the future. However, the dependence on expensive Pt-based electrocatalysts in such fuel cells remains a major obstacle for a widespread deployment of this technology. One solution to overcome this predicament is to reduce the Pt content by a factor of ten by replacing the Pt-based catalysts with non-precious metal catalysts at the oxygen-reducing cathode. Fe- and Co-based electrocatalysts for this reaction have been studied for over 50 years, but they were insufficiently active for the high efficiency and power density needed for transportation fuel cells. Recently, several breakthroughs occurred that have increased the activity and durability of non-precious metal catalysts (NPMCs), which can now be regarded as potential competitors to Pt-based catalysts. This review focuses on the new synthesis methods that have led to these breakthroughs. A modeling analysis is also conducted to analyze the improvements required from NPMC-based cathodes to match the performance of Pt-based cathodes, even at high current density. While no further breakthrough in volume-specific activity of NPMCs is required, incremental improvements of the volume-specific activity and effective protonic conductivity within the fuel-cell cathode are necessary. Regarding durability, NPMCs with the best combination of durability and activity result in ca. 3 times lower fuel cell performance than the most active NPMCs at 0.80 V. Thus, major tasks will be to combine durability with higher activity, and also improve durability at cell voltages greater than 0.60 V.
Prominent Neutralizing Antibody Response Targeting the Ebolavirus Glycoprotein Subunit Interface Elicited by Immunization (2021)

The severe death toll caused by the recent outbreak of Ebola virus disease reinforces the importance of developing ebolavirus prevention and treatment strategies. Here, we have explored the immunogenicity of a novel immunization regimen priming with vesicular stomatitis virus particles bearing Sudan Ebola virus (SUDV) glycoprotein (GP) that consists of GP1 & GP2 subunits and boosting with soluble SUDV GP in macaques, which developed robust neutralizing antibody (nAb) responses following immunizations. Moreover, EB46, a protective nAb isolated from one of the immune macaques, is found to target the GP1/GP2 interface, with GP-binding mode and neutralization mechanism similar to a number of ebolavirus nAbs from human and mouse, indicating that the ebolavirus GP1/GP2 interface is a common immunological target in different species. Importantly, selected immune macaque polyclonal sera showed nAb specificity similar to EB46 at substantial titers, suggesting that the GP1/GP2 interface region is a viable target for ebolavirus vaccine.<b>Importance:</b> The elicitation of sustained neutralizing antibody (nAb) responses against diverse ebolavirus strains remains as a high priority for the vaccine field. The most clinically advanced rVSV-ZEBOV vaccine could elicit moderate nAb responses against only one ebolavirus strain, EBOV, among the five ebolavirus strains, which last less than 6 months. Boost immunization strategies are desirable to effectively recall the rVSV vector-primed nAb responses to prevent infections in prospective epidemics, while an in-depth understanding of the specificity of immunization-elicited nAb responses is essential for improving vaccine performance. Here, using non-human primate animal model, we demonstrated that booster immunization with a stabilized trimeric soluble form of recombinant glycoprotein derived from the ebolavirus Sudan strain following the priming rVSV vector immunization led to robust nAb responses that substantially map to the subunit interface of ebolavirus glycoprotein, a common B cell repertoire target of multiple species including primates and rodents.
Identification of in-field defect development in digital image sensors (2007)

Although solid-state image sensors are known to develop defects in the field, little information is available about the nature, quantity or development rate of these defects. We report on and algorithm and calibration tests, which confirmed the existence of significant quantities of in-field defects in 4 out of 5 high-end digital cameras. Standard hot pixels were identified in all 4 cameras. Stuck hot pixels, which have not been described previously, were identified in 2 cameras. Previously, hot-pixels were thought to have no impact at short exposure durations, but the large offset of stuck hot pixels will degrade almost any image and cannot be ignored. Fully-stuck and abnormal sensitivity defects were not found. Spatial investigation found no clustering. We tracked hot pixel growth over the lifetime of one camera, using only normal photographs. We show that defects develop continually over the lifetime of the sensor, starting within several months of first use, and do not heal over time. Our success in tracing the history of each defect confirms the feasibility of using automatic defect identification to analyze defect response and growth characteristics in a multitude of cameras already in the field, without performing additional experiments or requiring physical access to the cameras.
An apparatus for collecting total conidia of <i>Blumeria graminis</i> f.sp. <i>hordei</i> from leaf colonies using electrostatic attraction (2006)

Conidia from living conidiophores of barley powdery mildew ( Blumeria graminis f.sp. hordei ) on host leaves were collected consecutively using an electrostatic spore collector. The collector consisted of an electrical conductor plate linked to an electrostatic voltage generator and insulator plates placed abreast on a timed conveyer. The conductor plate was negatively charged by the potential supplied from the voltage generator. The negatively charged conductor plate caused dielectric polarization of the insulator plate, and the surface charge on the insulator plate attracted mature conidia abstricted from conidiophores on colonies growing on leaves placed 2 cm from the insulator plate. The surface charge on the insulator plate was proportional to the voltage applied to the conductor plate. Under optimized conditions, abstricted conidia were attracted to the electrostatically activated insulator plates without any detriment to their survival. During a colony's life span of c . 460 h, conidia were released throughout the day and c . 12 × 10 4 conidia were collected during the lifetime of the colony. This is the first report on the direct quantification of progeny conidia produced by powdery mildew infecting host leaves.
High-resolution and fast-response fiber-optic temperature sensor using silicon Fabry-Pérot cavity (2015)

We report a fiber-optic sensor based on a silicon Fabry-Pérot cavity, fabricated by attaching a silicon pillar on the tip of a single-mode fiber, for high-resolution and high-speed temperature measurement. The large thermo-optic coefficient and thermal expansion coefficient of the silicon material give rise to an experimental sensitivity of 84.6 pm/°C. The excellent transparency and large refractive index of silicon over the infrared wavelength range result in a visibility of 33 dB for the reflection spectrum. A novel average wavelength tracking method has been proposed and demonstrated for sensor demodulation with improved signal-to-noise ratio, which leads to a temperature resolution of 6 × 10⁻⁴ °C. Due to the high thermal diffusivity of silicon, a response time as short as 0.51 ms for a sensor with an 80-µm-diameter and 200-µm-long silicon pillar has been experimentally achieved, suggesting a maximum frequency of ~2 kHz can be reached, to address the needs for highly dynamic environmental variations such as those found in the ocean.
Dual-Reporter Drift Correction To Enhance the Performance of Electrochemical Aptamer-Based Sensors in Whole Blood (2016)

The continuous, real-time monitoring of specific molecular targets in unprocessed clinical samples would enable many transformative medical applications. Electrochemical aptamer-based (E-AB) sensors appear to be a promising approach to this end because of their selectivity (performance in complex samples, such as serum) and reversible, single-step operation. E-AB sensors suffer, however, from often-severe baseline drift when challenged in undiluted whole blood. In response we report here a dual-reporter approach to performing E-AB baseline drift correction. The approach incorporates two redox reporters on the aptamer, one of which serves as the target-responsive sensor and the other, which reports at a distinct, nonoverlapping redox potential, serving as a drift-correcting reference. Taking the difference in their relative signals largely eliminates the drift observed for these sensors in flowing, undiluted whole blood, reducing drift of up to 50% to less than 2% over many hours of continuous operation under these challenging conditions.
Using Small Unmanned Aerial Systems and Helium Aerostats for Far-Field Radiation Pattern Measurements of High-Frequency Antennas (2018)

A new methodology is described for performing near-free space far-field radiation pattern measurements of high frequency and very-high frequency antennas to be employed as part of the radar science instrument system onboard NASA's planned Europa Clipper mission to Jupiter's moon Europa. Adapted from land-based measurements, this test methodology involves hoisting the antenna under test using a helium-filled aerostat above the earth to minimize ground interactions while flying a small unmanned aerial system (sUAS) with onboard RF measurement equipment package to map the far field radiation pattern. Prior to testing the technique using both airborne platforms - the aerostat and the sUAS - measurements are performed on the ground using the sUAS and a fixed VHF dipole over a ground plane to verify the methodology prior to incorporating the flying aerostat for airborne measurements of the HF dipole. These initial measurements have produced promising far-field pattern results with work remaining to fully adapt the fixed VHF antenna measurements to the dynamic HF antenna test setup that uses two airborne platforms (sUAS and aerostat) for measurements.