gebhart/patrepeval huggingface dataset:
Piezoelectric enhancement of Schottky barrier heights in GaN-AlGaN HFET structures (2002)

We describe here the design, experimental characterisation, and analysis of GaN-Al/sub x/Ga/sub 1-x/N HFET structures in which the piezoelectric effect is employed to achieve a marked enhancement of the effective Schottky barrier height. Specifically, a two-layer GaN-Al/sub x/Ga/sub 1-x/N barrier is employed, within which the piezoelectrically induced polarization charge acts to increase the electrostatic potential, and consequently the barrier height for gate leakage current in the HFET. This can be accomplished with no increase in barrier thickness, and consequently little if any change in gate capacitance, and with only a minor impact on carrier concentration in the channel. It is anticipated that this will allow gate currents to be significantly reduced in nitride HFETs with little if any penalty exacted in terms of channel conductance, transconductance, and other device properties.
-Conotoxin PIA Is Selective for6 Subunit-Containing Nicotinic Acetylcholine Receptors (2003)

Until now, there have been no antagonists to discriminate between heteromeric nicotinic acetylcholine receptors (nAChRs) containing the very closely related 6 and 3 subunits. nAChRs containing 3, 4, or 6 subunits in combination with 2, occasionally 4, and sometimes 3o r5 subunits, are thought to play important roles in cognitive function, pain perception, and the reinforcing properties of nicotine. We cloned a novel gene from the predatory marine snail Conus purpurascens. The predicted peptide, -conotoxin PIA, potently blocks the chimeric 6/323 subunit combination as expressed in oocytes but neither the muscle nor the major neuronal nAChR 42. Additionally, this toxin is the first described ligand to discriminate between nAChRs containing 6 and 3 subunits. Exploiting the unusual intron conservation of conotoxin genes may represent a more general approach for defining conotoxin ligand scaffolds to discriminate among closely related receptor populations.
Optical systems for efficient triple-matrix-product processing (1983)

Three different optical systems are developed for efficient evaluation of a triple-matrix product of the form [U][G][V]. One system uses a purely space-integrating architecture, whereas the other two use hybrid time- and space-integrating architectures. Each of these three systems has a distinct format for input [using one-dimensional (1-D) and two-dimensional (2-D) spatial light modulators] and output (using either 1-D or 2-D time-integrating detector arrays or high-bandwidth single-element detectors) devices, thus permitting a trade-off between parameters such as speed and dynamic range. Potential applications for these systems include image data compression and orthogonal transforms of coefficient matrices encountered in linear systems analysis.
High performance fourier transform ion cyclotron resonance mass spectrometric detection for capillary electrophoresis (1996)

Abstract We describe the current state of the on‐line combination of capillary electrophoresis (CE) electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FTICR) mass spectrometry (MS), and discuss aspects of the FTICR technique relevant to its use as a detection scheme for on‐line separations. Aspects including sensitivity, mass resolution, duty cycle, and tandem mass spectrometric capabilities are discussed in the context of online separations with examples from the authors' laboratory.
Solubilization of subtilisin in CO2 using fluoroether-functional amphiphiles (1998)

Carbon dioxide is a naturally abundant, environmentally benign solvent whose use, like water, in a process is not regulated by either EPA or FDA. Unfortunately, polar compounds such as amino acids and proteins are essentially insoluble in carbon dioxide. Further, alkyl-functional surfactants, which have been shown to allow extraction of proteins into conventional organic solvents, exhibit very poor or negligible solubility in CO2 at pressures below 50 MPa. Consequently, highly CO2-soluble fluoroether-functional surfactants have been generated and used to solubilize subtilisin Carlsberg from aqueous buffer and cell culture medium into CO2, with recovery accomplished by depressurization. Both the amount of protein solubilized in the emulsion and the extent of activity retention by the protein following recovery are functions of the initial protein concentration in the buffer. This, plus the observation that the presence of protein affects the stability of the emulsion, suggests that some of the protein is sacrificed to act as a stabilizer in these systems. In addition to solubilization via an inverse emulsion, it has also been shown that one can strip protein-surfactant aggregates from a middle phase emulsion using pure CO2, suggesting an ion-pairing type mechanism.
A fast analysis method for non-invasive imaging of blood flow in individual cerebral arteries using vessel-encoded arterial spin labelling angiography (2011)

Arterial spin labelling (ASL) MRI offers a non-invasive means to create blood-borne contrast in vivo for dynamic angiographic imaging. By spatial modulation of the ASL process it is possible to uniquely label individual arteries over a series of measurements, allowing each to be separately identified in the resulting angiographic images. This separation requires appropriate analysis for which a general Bayesian framework has previously been proposed. Here this framework is adapted for clinical dynamic angiographic imaging. This specifically addresses the issues of computational speed of the algorithm and the robustness required to deal with real patient data. An algorithm is proposed that can incorporate planning information about the arteries being imaged whilst adapting for subsequent patient movement. A fast maximum a posteriori solution is adopted and shown to be only marginally less accurate than Monte Carlo sampling under simulation. The final algorithm is demonstrated on in vivo data with analysis on a time scale of the order of 10min, from both a healthy control and a patient with a vertebro-basilar occlusion.
Volume holographic imaging for surface metrology with long working distances (2004)

Volume holographic imaging (VHI) utilizes the Bragg selectivity of volume holograms to achieve 3D optical slicing. The depth resolution of VHI degrades quadratically with increasing object distance like most 3D imaging systems. We have devised an imaging scheme that takes advantage of the superior lateral resolution of VHI and a-priori surface information about the object to build a profilometer that can resolve 50 μm features at a working distance of ≈ 50 cm. We discuss the scheme and present experimental results of surface profiles of MEMS devices.
Integrating Radiomics With Clinicoradiological Scoring Can Predict High-Risk Patients Who Need Surgery in Crohn’s Disease: A Pilot Study (2022)

Radiomic features on MRE may be associated with risk of surgery in CD, and in combination with clinicoradiological scoring can yield an accurate prognostic model for time to surgery.
Die exzitotoxische Hypothese der Glaukomgenese (1999)

Glaucoma can be defined as a disease in which one of the pathophysiological consequences of raised intra-ocular pressure is damage of the optic nerve, and subsequently the loss of retinal ganglion cells (RGCs). One of the main aims of modern glaucoma therapy is to alter the intraocular pressure, either surgically or pharmacologically. Recently it was shown that the vitreous of glaucoma patients contains increased levels of glutamate (27 microM as compared to 11 microM in controls). This concentration of glutamate is sufficient to induce retinal ganglion cell death. The rise in intraocular pressure is probably the initial insult, which enhances the increase or release of glutamate. Although the increase in intravitreal glutamate levels is an accompanying feature of glaucoma, it could contribute to the loss of retinal ganglion cells in humans itself. Therefore, despite efficient control of intra-ocular pressure, RGC's loss will continue resulting in further visual impairment, if the toxic effect of glutamate is not blocked. If it would be possible to understand the mechanism leading to excessive vitreous levels of glutamate in glaucoma or to block its toxic effects, then the resulting visual loss could be retarded. This review discusses various proposed mechanisms leading to intraocular glutamate toxicity and the role of neuroprotection in this disease. (Literature search by Medline).
Beneficial characteristics of mechanically functional amyloid fibrils evolutionarily preserved in natural adhesives (2006)

While biological systems are notorious for their complexity, nature sometimes displays mechanisms that are elegant in their simplicity. We have recently identified such a mechanism at work to enhance the mechanical properties of certain natural adhesives. The mechanism is simple because it utilizes a non-specific protein folding and subsequent aggregation process, now thought to be generic for any polypeptide under appropriate conditions. This non-specific folding forms proteinaceous crossed β-sheet amyloid fibrils, which are usually associated with neurodegenerative diseases. Here we show evidence for the beneficial mechanical characteristics of these fibrils discovered in natural adhesives. We suggest that amyloid protein quaternary structures should be considered as a possible generic mechanism for mechanical strength in a range of natural adhesives and other natural materials due to their many beneficial mechanical features and apparent ease of self-assembly.
Efficient Indexing Mechanism for Unstructured Data Sharing Systems in Edge Computing (2019)

Edge computing promises a dramatic reduction in the network latency and the traffic volume, where many edge servers are placed at the edge of the Internet. Furthermore, these edge servers cache data to provide services for edge users. The data sharing among edge servers can effectively shorten the latency to retrieve the data and further reduce the network bandwidth consumption. The key challenge is to construct an efficient data indexing mechanism no matter how the data is cached in the edge network. Although this is essential, it is still an open problem. Moreover, existing methods such as the centralized indexing and the DHT indexing in other fields fail to meet the performance demand of edge computing. This paper presents a COordinate-based INdexing (COIN) mechanism for the data sharing in edge computing. COIN maintains a virtual space where the switches and the data indexes are associated with the coordinates. Then, COIN distributes data indexes to indexing edge servers based on those coordinates. The COIN is effective because any query request from an edge server can be responded when the data has been stored in the edge network. More importantly, COIN is efficient in both routing path lengths and forwarding table sizes for publishing/querying the data indexes. We implement COIN in a P4 prototype. Experimental results show that COIN uses 59% shorter path length and 30% less forwarding table entries to retrieve the data index compared to using Chord, a well-known DHT solution.
An integrated five-step continuous flow synthesis of 2-(1-cyclohexenyl)ethylamine: a key intermediate for morphinans (2023)

A continuous flow synthesis of 2-(1-cyclohexenyl)ethylamine started from cyclohexanone was developed through telescoping Grignard reaction and chlorination, telescoping amination and double bond rearrangement, and hydrazinolysis.
ChemInform Abstract: Semisynthesis of Human Complex Type Oligosaccharide Library and Chemical Synthesis of Glycopeptides and Glycoprotein (2009)

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Large-Scale Privacy-Preserving Mapping of Human Genomic Sequences on Hybrid Clouds. (2012)

An operation preceding most human DNA analyses is read mapping, which aligns millions of short sequences (called reads) to a reference genome. This step involves an enormous amount of computation (evaluating edit distances for millions upon billions of sequence pairs) and thus needs to be outsourced to low-cost commercial clouds. This asks for scalable techniques to protect sensitive DNA information, a demand that cannot be met by any existing techniques (e.g., homomorphic encryption, secure multiparty computation). In this paper, we report a new step towards secure and scalable read mapping on the hybrid cloud, which includes both the public commercial cloud and the private cloud within an organization. Inspired by the famous “seed-and-extend” method, our approach strategically splits a mapping task: the public cloud seeks exact matches between the keyed hash values of short read substrings (called seeds) and those of reference sequences to roughly position reads on the genome; the private cloud extends the seeds from these positions to find right alignments. Our novel seed-combination technique further moves most workload of this task to the public cloud. The new approach is found to work effectively against known inference attacks, and also easily scale to millions of reads.
Design of fixed- and varactor-tuned bandstop filters with spurious suppression (2010)

A new spurious suppression method for bandstop filters based on constructive interference is presented. The technique is successfully applied to realize a fixed-tuned filter with an upper passband extending more than 9 times the fundamental bandstop response, as well as a varactor-tuned bandstop filter with an upper passband extending to 8.9 times the fundamental.
Inductor Free Methods for Breaking DC Currents (2021)

The current interruption in dc circuits is more difficult to achieve compared to the ac circuits because, unlike ac systems, dc circuits do not have the natural current zero-crossing. Presently there are three categories of basic dc breaker models namely mechanical, static, and hybrid dc breakers. As current power systems is moving more towards microgrids, DERs, Electric Vehicles (EVs), and with recent advancements in dc circuits, wide verities of dc power sources, and loads, dc breakers are very important in future system protection. New alternate methods to break dc currents for low-voltage applications are proposed in this work. The proposed mechanisms utilize two separate principles to clear the dc faults. In the first mechanism, I use one switch to generate zero-crossing with an alternate oscillatory circuit and use another switch, which can be a conventional low-cost ac breaker and is used in the main circuit, in series with the first switch. In the second breaker prototype, I use two switches in series along with two anti-parallel diodes, to change the direction of the current flow and clear the fault. It is shown in this dissertation that the proposed methods can break the fault current quickly with minimal arc and reduce the switching voltage stress across the switches and other components. The performances of the proposed breakers were also compared to the available models to show the effectiveness of them over available models. Additionally, I also, modified our prototype and made use of surge arresters as a voltage suppressing device. Lastly, I tested our breaker model at 1000V testbed and it showed promising results.
Two-dimensional DOA Estimation for Coprime Planar Array: A Coarray Tensor-based Solution (2020)

Coprime arrays can cope with the underdetermined case for direction-of-arrival (DOA) estimation. However, the popular matrix-based coarray signal processing approaches suffer performance loss on the underlying characteristics among the multi-dimensional signals. To address this problem, we propose a novel coarray tensor-based two-dimensional underdetermined DOA estimation method for coprime planar array in this paper, where both the multi-dimensional information of the received signals and the augmented coarray are effectively utilized. The received signal tensors of the coprime planar array are constructed by concatenating each snapshot, which are then transformed to an augmented uniform rectangular array statistics for extending the effective array aperture. Subsequently, the tensorization technique is adopted to increase the degrees-of-freedom of the proposed DOA estimation method, and a structured coarray tensor is optimized for super-resolution DOA estimation. The effectiveness of the proposed method is verified via simulation results.
The Gene Related to Anergy in Lymphocytes, an E3 Ubiquitin Ligase, Is Necessary for Anergy Induction in CD4 T Cells (2004)

Acquisition of the anergy phenotype in T cells is blocked by inhibitors of protein synthesis and calcineurin activity, suggesting that anergic T cells may have a unique genetic program. Retroviral transduction of hemopoietic stem cells from TCR transgenic mice and subsequent reconstitution of syngeneic mice to express the E3 ubiquitin ligase, gene related to anergy in lymphocytes (GRAIL), or an enzymatically inactive form, H2N2 GRAIL, allowed analysis of the role of GRAIL in T cell anergy in vivo. Constitutive expression of GRAIL was sufficient to render naive CD4 T cells anergic, however, when the enzymatically inactive form H2N2 GRAIL was expressed, it functioned as a dominant negative of endogenous GRAIL and blocked the development of anergy. These data provide direct evidence that a biochemical pathway composed of GRAIL and/or GRAIL-interacting proteins is important in the development of the CD4 T cell anergic phenotype in vivo.
Application of the okahara cyclization to the preparation of crown ethers with aromatic units (1984)

Abstract A series of crown ethers with single benzene, naphthalene, biphenyl and binaphthyl units are prepared by the intramolecular Okahara cyclization of appropriate symmetrical diols. The method is used to synthesize new crown ether compounds and to prepare previously‐reported crown ethers in improved yields.
Aziridine-Functionalized Mesoporous Silica Membranes on Polymeric Hollow Fibers: Synthesis and Single-Component CO<sub>2</sub> and N<sub>2</sub> Permeation Properties (2014)

The synthesis of aziridine-functionalized mesoporous silica membranes on polymeric hollow fibers is described, and their single-component CO2 and N2 permeation properties are investigated under both dry and humid conditions to elucidate the unusual permeation mechanisms observed in these membranes. Hollow fiber-supported mesoporous silica membranes are amine-functionalized with aziridine to yield hyperbranched aminopolymers within the membrane pores. The effects of the hyperbranched polymers in the mesopores on gas transport properties are investigated by single-component gas permeation measurements. The hyperbranched aminosilica membrane shows counterintuitive N2-selective (over CO2) permeation during operation under dry conditions. Further characterization of the permeation behavior reveals the effects of strong adsorption of CO2 under dry permeation conditions, leading to reduced CO2 diffusivity because of CO2-induced amine cross-linking in the mesopores. On the other hand, the hyperbranched aminosilica membrane shows CO2-selective properties under humid conditions. Water molecules cause a lower degree of amine cross-linking and thus allow facilitated transport of CO2. This first study of hollow fiber-supported hyperbranched aminosilica membranes indicates that they can be tuned to have N2- or CO2-selective permeation properties under the conditions employed.
Sensor materials for an intravascular fiber optic nitric oxide sensor (1996)

Nitric oxide (NO) is an important regulatory molecule in physiological processes including neurotransmission and the control of blood pressure. It is produced in excess during septic shock, the profound hypotensive state which accompanies severe infections. In-vivo measurement of NO would enhance the understanding of its varied biological roles. Our goal is the development of an intravascular fiber-optic sensor for the continuous measurement of NO. This study evaluated nitric oxide sensitive compounds as potential sensing materials in the presence and absence of oxygen. Using absorption spectroscopy we studied both the Fe II and Fe III forms of three biologically active hemes known to rapidly react with NO: hemoglobin, myoglobin, and cytochrome-c. The Fe II forms of hemoglobin and myoglobin and the Fe III form of cytochrome-c were found to have the highest sensitivity to NO. Cytochrome c (Fe III) is selective for NO even at high oxygen levels, while myoglobin is selective only under normal oxygen levels. NO concentrations as low as 1 (mu) M can be detected with our fiber-optic spectrometer using cytochrome c, and as low as 300 nM using myoglobin. Either of these materials would be adequate to monitor the increase in nitric oxide production during the onset of septic shock.
Synergistic effects between catalase inhibitors and modulators of nitric oxide metabolism on tumor cell apoptosis. (2014)

Inhibitors of catalase (such as ascorbate, methyldopa, salicylic acid and neutralizing antibodies) synergize with modulators of nitric oxide (NO) metabolism (such as arginine, arginase inhibitor, NO synthase-inducing interferons and NO dioxygenase inhibitors) in the singlet oxygen-mediated inactivation of tumor cell protective catalase. This is followed by reactive oxygen species (ROS)-dependent apoptosis induction. TGF-beta, NADPH oxidase-1, NO synthase, dual oxidase-1 and caspase-9 are characterized as essential catalysts in this process. The FAS receptor and caspase-8 are required for amplification of ROS signaling triggered by individual compounds, but are dispensable when the synergistic effect is established. Our findings explain the antitumor effects of catalase inhibitors and of compounds that target NO metabolism, as well as their synergy. These data may have an impact on epidemiological studies related to secondary plant compounds and open new perspectives for the establishment of novel antitumor drugs and for the improvement of established chemotherapeutics.
An Active Sequential Xampling Detector for Spectrum Sensing (2018)

Nyquist sampling at very high carriers can be prohibitively costly for low power wireless devices. In spectrum sensing, this limit calls for an analog front-end that can sweep different bands quickly, in order to use the available spectrum opportunistically. In this paper, we propose a new sub-Nyquist analog front-end and a sensing strategy formulated as a sequential utility optimization problem. The sensing action maximizes a utility function decreasing linearly with the number of measurements, and increasing as a function of the active spectrum components that are correctly detected. The optimization selects the best linear combinations of sub-bands to mix, in order to accrue maximum utility. The structure of the utility represents the tradeoff between exploration, exploitation, and risk of making an error, that is characteristic of the spectrum sensing problem. We first present the analog front-end architecture, and then map the measurement model into the abstract optimization problem proposed, and analyzed, in the remainder of this paper. We characterize the optimal policy, under constraints on the sensing matrix, and derive the approximation factor of the greedy approach we introduce to solve the problem. Numerical simulations showcase the benefits of combining active spectrum sensing with sub-Nyquist sampling.