gebhart/patrepeval huggingface dataset:
Studies in Polyphenol Chemistry and Bioactivity. 4.1 Synthesis of Trimeric, Tetrameric, Pentameric, and Higher Oligomeric Epicatechin-Derived Procyanidins Having All-4β,8-Interflavan Connectivity and Their Inhibition of Cancer Cell Growth through Cell Cycle Arrest1 (2002)

We report an improved synthesis of bis(5,7,3',4'-tetra-O-benzyl)epicatechin 4beta,8-dimer (3) from 5,7,3',4'-tetra-O-benzylepicatechin (1) and 5,7,3',4'-tetra-O-benzyl-4-(2-hydroxyethoxy)epicatechin (2) by replacing the previously employed Lewis acid, titanium tetrachloride, with the clay mineral Bentonite K-10. Under the same conditions, the benzyl-protected all-4beta,8-trimer, -tetramer, and -pentamer were obtained regioselectively from their lower homologues, albeit in rapidly decreasing yields. Reaction of 2 with an organoaluminum thiolate generated from 2-mercaptobenzothiazole and trimethylaluminum followed by acetylation produced 3-O-acetyl-4-[(2-benzothiazolyl)thio]-5,7,3',4'-tetra-O-benzylepicatechin (12). Medium-sized protected oligomers with 4beta,8-interflavan linkages are obtained in improved yields by using this compound as the electrophile and silver tetrafluoroborate as activator and are isolated by reversed-phase HPLC. Their deprotection by ester saponification followed by hydrogenolysis yielded the free procyanidins, which were characterized as their peracetates. The synthetic procyanidins are identical by normal-phase HPLC with fractions isolated from cocoa. The principle of chain extension by two members was demonstrated using a dimeric electrophile obtained by self-condensation of compound 12. Both the synthetic and natural pentamer 32 inhibit the growth of several breast cancer cell lines. Using the MDA MB 231 line, it was established that this outcome is based on the induction of cell cycle arrest in the G0/G1 phase. Subsequent cell death is more likely necrotic rather than apoptotic. Control experiments demonstrate that the polyphenol itself, rather than hydrogen peroxide potentially formed by its autoxidation, is the causative agent.
Kinetics of Semiconductor Surface Chemistry: Silicon Atomic Layer Processing (1993)

Surface Kinetics play a crucial role in semiconductor processing chemistry. Our research concentrates on fundamental understanding of microscopic surface kinetics that dictate surface chemistry. We are exploring the various adsorption, decomposition, diffusion and desorption steps in reactions on single-crystal silicon surfaces. These basic time-dependent surface processes are examined using laser induced thermal desorption (LITD) and Fourier transform infrared (FTIR) techniques. These techniques provide direct, quantitative measurements of surface coverage in real-time. Atomic layer processing is a vital need for semiconductor fabrication. As the size of electronic devices approaches the nanometer scale, the need to control growth on an atomic scale is extremely important. For the construction of next generation devices, controlled atomic layer-by-layer processing during oxidation, growth, etching and metallization is critical.
Algorithm to automatically detect abnormally long periods of inactivity in a home (2007)

An algorithm has been developed to automatically construct individual models of normal activity within a home using motion sensor data. Alerts can be generated when a period of inactivity exceeds a normal length for a particular residence. Alerting frequency has been optimized on a total of 650 days of real data from four homes of seniors who live independently. Results suggest that an inexpensive system that does not require the occupant to push any buttons or wear any devices could nonetheless alert within hours if a senior is unusually inactive. Further, such algorithms may facilitate widespread deployment of smart home technology to persons with different behavior patterns and home layouts by using automatic learning in place of potentially tedious manual configuration.
Photocrosslinkable hyaluronic acid for cell encapsulation (2003)

The microencapsulation of human or animal islets of Langerhans cells, which contain the insulin producing beta cells, in crosslinked polymers has been investigated for the treatment of diabetes. We have developed a modified hyaluronic acid biopolymer for islet cell encapsulation that possesses several advantages over previous systems. The physical and chemical properties of these photocrosslinked microcapsules have been characterized and preliminary in vitro and in vivo experiments of islet cell encapsulation have been initiated.
ChemInform Abstract: Synthesis and Biological Activity of Natural Aminocyclopentitol Glycosidase Inhibitors: Mannostatins, Trehazolin, Allosamidins, and Their Analogues (1999)

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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.
Verification techniques for cache coherence protocols (1997)

In this article we present a comprehensive survey of various approaches for the verification of cache coherence protocols based on state enumeration, (symbolic model checking , and symbolic state models . Since these techniques search the state space of the protocol exhaustively, the amount of memory required to manipulate that state information and the verification time grow very fast with the number of processors and the complexity of the protocol mechanisms. To be successful for systems of arbitrary complexity, a verification technique must solve this so-called state space explosion problem. The emphasis of our discussion is onthe underlying theory in each method of handling the state space exposion problem, and formulationg and checking the safety properties (e.g., data consistency) and the liveness properties (absence of deadlock and livelock). We compare the efficiency and discuss the limitations of each technique in terms of memory and computation time. Also, we discuss issues of generality, applicability, automaticity, and amenity for existing tools in each class of methods. No method is truly superior because each method has its own strengths and weaknesses. Finally, refinements that can further reduce the verification time and/or the memory requirement are also discussed.
Differential Expression of CD96 Surface Molecule Represents CD8+ T Cells with Dissimilar Effector Function during HIV-1 Infection (2012)

During HIV-1 infection, immune dysregulation and aberrant lymphocyte functions are well-established characteristics. Cell surface molecules are important for immunological functions and changes in expression can affect lymphocyte effector functions, thereby contributing to pathogenesis and disease progression. In this study we have focused on CD96, a member of the IgG superfamily receptors that have generated increasing recent interest due to their adhesive and co-stimulatory functions in addition to immunoregulatory capacity. CD96 is expressed by both T and NK cells. Although the function of CD96 is not completely elucidated, it has been shown to have adhesive functions and enhance cytotoxicity. Interestingly, CD96 may also have inhibitory functions due to its immunoreceptor tyrosine-based inhibitory motif (ITIM). The clinical significance of CD96 is still comparatively limited although it has been associated with chronic Hepatitis B infection and disease progression. CD96 has not previously been studied in the context of HIV-1 infection, but due to its potential importance in immune regulation and relevance to chronic disease, we examined CD96 expression in relation to HIV-1 pathogenesis. In a cross-sectional analysis, we investigated the CD8(+) T cell expression of CD96 in cohorts of untreated HIV-1 infected adults with high viral loads (non-controllers) and low viral loads ("elite" controllers). We demonstrated that elite controllers have significantly higher CD96 mean fluorescence intensity on CD8(+) T cells compared to HIV-1 non-controllers and CD96 expression was positively associated with CD4(+) T cell counts. Functional assessment showed that CD8(+) T cells lacking CD96 expression represented a population that produced both perforin and IFN-γ following stimulation. Furthermore, CD96 expression on CD8(+) T cells was decreased in presence of lipopolysaccharide in vitro. Overall, these findings indicate that down-regulation of CD96 is an important aspect of HIV-1 pathogenesis and differential expression is related to cell effector functions and HIV-1 disease course.
Immediate ex-vivo diagnosis of pituitary adenomas using confocal reflectance microscopy: a proof-of-principle study (2017)

OBJECTIVE The objective of this study was to evaluate the feasibility of using confocal reflectance microscopy (CRM) ex vivo to differentiate adenoma from normal pituitary gland in surgical biopsy specimens. CRM allows for rapid, label-free evaluation of biopsy specimens with cellular resolution while avoiding some limitations of frozen section analysis. METHODS Biopsy specimens from 11 patients with suspected pituitary adenomas were transported directly to the pathology department. Samples were immediately positioned and visualized with CRM using a confocal microscope located in the same area of the pathology department where frozen sections are prepared. An H & E-stained slide was subsequently prepared from imaged tissue. A neuropathologist compared the histopathological characteristics of the H & E-stained slide and the matched CRM images. A second neuropathologist reviewed images in a blinded fashion and assigned diagnoses of adenoma or normal gland. RESULTS For all specimens, CRM contrasted cellularity, tissue architecture, nuclear pleomorphism, vascularity, and stroma. Pituitary adenomas demonstrated sheets and large lobules of cells, similar to the matched H & E-stained slides. CRM images of normal tissue showed scattered small lobules of pituitary epithelial cells, consistent with matched H & E-stained images of normal gland. Blinded review by a neuropathologist confirmed the diagnosis in 15 (94%) of 16 images of adenoma versus normal gland. CONCLUSIONS CRM is a simple, reliable approach for rapidly evaluating pituitary adenoma specimens ex vivo. This technique can be used to accurately differentiate between pituitary adenoma and normal gland while preserving biopsy tissue for future permanent analysis, immunohistochemical studies, and molecular studies.
γ-Secretase Modulator (GSM) Photoaffinity Probes Reveal Distinct Allosteric Binding Sites on Presenilin (2013)

γ-Secretase is an intramembrane aspartyl protease that cleaves the amyloid precursor protein to produce neurotoxic β-amyloid peptides (i.e. Aβ42) that have been implicated in the pathogenesis of Alzheimer disease. Small molecule γ-secretase modulators (GSMs) have emerged as potential disease-modifying treatments for Alzheimer disease because they reduce the formation of Aβ42 while not blocking the processing of γ-secretase substrates. We developed clickable GSM photoaffinity probes with the goal of identifying the target of various classes of GSMs and to better understand their mechanism of action. Here, we demonstrate that the photoaffinity probe E2012-BPyne specifically labels the N-terminal fragment of presenilin-1 (PS1-NTF) in cell membranes as well as in live cells and primary neuronal cultures. The labeling is competed in the presence of the parent imidazole GSM E2012, but not with acid GSM-1, allosteric GSI BMS-708163, or substrate docking site peptide inhibitor pep11, providing evidence that these compounds have distinct binding sites. Surprisingly, we found that the cross-linking of E2012-BPyne to PS1-NTF is significantly enhanced in the presence of the active site-directed GSI L-685,458 (L458). In contrast, L458 does not affect the labeling of the acid GSM photoprobe GSM-5. We also observed that E2012-BPyne specifically labels PS1-NTF (active γ-secretase) but not full-length PS1 (inactive γ-secretase) in ANP.24 cells. Taken together, our results support the hypothesis that multiple binding sites within the γ-secretase complex exist, each of which may contribute to different modes of modulatory action. Furthermore, the enhancement of PS1-NTF labeling by E2012-BPyne in the presence of L458 suggests a degree of cooperativity between the active site of γ-secretase and the modulatory binding site of certain GSMs.
A New Strain Energy Function Representing the Passive Behavior of the Myocardium (2023)

Classical models for the passive myocardium, such as the Fung and Holzapfel-Ogden models, are known to have high degeneracy as well as numerous mechanical and mathematical limitations, preventing their utility in microstructural experiments and precision medicine. Hence, the upper triangular (QR) decomposition and orthogonal strain attributes were leveraged to develop a new model using published biaxial data on slabs of left myocardium, resulting in a separable strain energy function. This new model, the Criscione-Hussein model, was compared with both the Fung and Holzapfel-Ogden models by quantifying the uncertainty, computational efficiency, and material parameter fidelity for all three models. As a result, the Criscione-Hussein model was found to significantly reduce the uncertainty and computational time (p < 0.05) and enhance the fidelity of the material parameters. Hence, the Criscione-Hussein model enhances the predictability for the passive behavior of the myocardium and may serve a role in creating more accurate computational models that provide better visualizations for the mechanical behavior of the heart and enable the experimental connection between the model and the myocardial microstructure.
Bit error rates of IR-UWB transceiver types at sub-nyquist sampling rates (2006)

Impulse-radio (IR) ultra-wideband (UWB) communications can be achieved with various transceiver architectures. Even though matched filtering is the optimal signal detection technique with Nyquist rate sampling, differentially coherent and non-coherent transceiver architectures may be favorable at lower rate samples. In this paper, we present a unified performance analysis approach for different IR-UWB transceiver types employing various modulation options and using the captured energy statistics at sub-Nyquist sampling rates. Energy capture versus robustness against noise is demonstrated as a trade-off for stored-reference transceivers. Theoretical results are verified via simulations
Proton magnetic resonance study of the stereochemistry of a macrocyclic Schiff base-amine complex of nickel(II) (1968)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTProton magnetic resonance study of the stereochemistry of a macrocyclic Schiff base-amine complex of nickel(II)Larry G. Warner, Norman J. Rose, and Daryle H. BuschCite this: J. Am. Chem. Soc. 1968, 90, 25, 6938–6946Publication Date (Print):December 1, 1968Publication History Published online1 May 2002Published inissue 1 December 1968https://pubs.acs.org/doi/10.1021/ja01027a008https://doi.org/10.1021/ja01027a008research-articleACS PublicationsRequest reuse permissionsArticle Views778Altmetric-Citations51LEARN 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
Simple autocorrelation technique by tuning a DGD element and measuring a pulse's degree-of-polarization (2005)

We demonstrate a simple optical-fiber-based autocorrelator based on degree-of-polarization measurement while tuning a DGD element. The pulse widths of 20-80 GHz pulse trains and 2-ps pulses generated by a mode-lock laser are accurately measured. (2 pages)
Effect of Young's Modulus on the Detachment Force of 7 μm Particles (2005)

The detachment force of ground, 7-microm-diameter polyester particles overcoated with clusters of silica having a cluster radius of approximately 100 nm from ceramer substrates with varying Young's moduli has been measured. It was found that the detachment force varied inversely with the Young's modulus of the ceramer. The results are attributed to the role of the silica, acting as asperities on the particles, and the degree of embedment of the particles into the substrate.
Applying matching pursuit decomposition time-frequency processing to UGS footstep classification (2013)

The challenge of rapid footstep detection and classification in remote locations has long been an important area of study for defense technology and national security. Also, as the military seeks to create effective and disposable unattended ground sensors (UGS), computational complexity and power consumption have become essential considerations in the development of classification techniques. In response to these issues, a research project at the Flexible Display Center at Arizona State University (ASU) has experimented with footstep classification using the matching pursuit decomposition (MPD) time-frequency analysis method. The MPD provides a parsimonious signal representation by iteratively selecting matched signal components from a pre-determined dictionary. The resulting time-frequency representation of the decomposed signal provides distinctive features for different types of footsteps, including footsteps during walking or running activities. The MPD features were used in a Bayesian classification method to successfully distinguish between the different activities. The computational cost of the iterative MPD algorithm was reduced, without significant loss in performance, using a modified MPD with a dictionary consisting of signals matched to cadence temporal gait patterns obtained from real seismic measurements. The classification results were demonstrated with real data from footsteps under various conditions recorded using a low-cost seismic sensor.
A seven-membered cell wall related transglycosylase gene family in Aspergillus niger is relevant for cell wall integrity in cell wall mutants with reduced α-glucan or galactomannan (2020)

Chitin is an important fungal cell wall component that is cross-linked to β-glucan for structural integrity. Acquisition of chitin to glucan cross-links has previously been shown to be performed by transglycosylation enzymes in <i>Saccharomyces cerevisiae</i>, called Congo Red hypersensitive (Crh) enzymes. Here, we characterized the impact of deleting all seven members of the <i>crh</i> gene family (<i>crhA-G</i>) in <i>Aspergillus niger</i> on cell wall integrity, cell wall composition and genome-wide gene expression. In this study, we show that the seven-fold <i>crh</i> knockout strain shows slightly compact growth on plates, but no increased sensitivity to cell wall perturbing compounds. Additionally, we found that the cell wall composition of this knockout strain was virtually identical to that of the wild type. In congruence with these data, genome-wide expression analysis revealed very limited changes in gene expression and no signs of activation of the cell wall integrity response pathway. However, deleting the entire <i>crh</i> gene family in cell wall mutants that are deficient in either galactofuranose or α-glucan, mainly α-1,3-glucan, resulted in a synthetic growth defect and an increased sensitivity towards Congo Red compared to the parental strains, respectively. Altogether, these results indicate that loss of the <i>crh</i> gene family in <i>A. niger</i> does not trigger the cell wall integrity response, but does play an important role in ensuring cell wall integrity in mutant strains with reduced galactofuranose or α-glucan.
Improving the filtration properties for manganese tetroxide mud utilizing perlite particles to drill wide-range permeability sandstone formation (2022)

A required feature of any drilling formulation is to mitigate the formation damage by having an excellent filtration and filter cake properties. The key factor for preventing and limiting formation damage is to improve the sealing qualities of the planned drilling fluid. In this study, a new novel filtration agent called "perlite" was introduced for improving the manganese tetroxide mud cake ability for better sealing features. The perlite particles were loaded to formulation containing the manganese tetroxide as weighting agent. The water-based drilling mud was designed at high densities (14.25 and 17.2 ppg). Perlite was added in varied concentrations to reach the optimum performance. The filtration test conducted at reservoir temperature of 250 °F and a differential pressure of 300 psi to form the filter cake. The tests were performed using sandstone cores with two different permeability categories (low and high permeabilities) as the filtration media. This gave the full picture of perlite performance as implemented for different formation properties and considering the drilling fluid properties. The formed filter cake structure and chemical composition was evaluated using scanning electron energy-dispersive X-ray (SEM-EDS). The presented results illustrated how the perlite was compatible to be added to the manganese tetroxide weighting agents in the same formulation. In addition, it has the capacity to improve the filter cake's sealing qualities, lowering the filtration volume by 41% and the filter cake internal and external layers permeability by 58% and 25%, respectively. Moreover, the EDS analysis showed that the perlite particles are concentrated generally in the internal layer of the filter cake.