gebhart/patrepeval huggingface dataset:
Development of Star Polymers as Unimolecular Containers for Nanomaterials (2012)

Star polymers containing one central core surrounded by multiple radiating arms represent an intriguing type of globular platform to be used as unimolecular containers and reactors. The core domain can encapsulate guest "cargos", whereas protective shell and chain ends can be functionalized with reactive groups and ligands. This Feature Article highlights the recent development on using core-shell structured amphiphilic star polymers as unimolecular containers for applications in drug delivery, catalysis, and template of hybrid nanomaterials. As compared with dendrimers, star polymers enjoy advantages of facile synthesis, flexible compositions, and tunable sizes, which allow them being able to carry more and multiple "cargos" within one molecule.
A Recombinationally Repressed Region Between mat2 and mat3 Loci Shares Homology to Centromeric Repeats and Regulates Directionality of Mating-Type Switching in Fission Yeast (1997)

Cells of the fission yeast Schizosaccharomyces pombe switch mating type by replacing genetic information at the transcriptionally active mat1 locus with sequences copied from one of two closely linked silent loci, mat2-P or mat3-M. By a process referred to as directionality of switching, cells predominantly switch to the opposite mat1 allele; the mat1-P allele preferentially recombines with mat3, while mat1-M selects the mat2. In contrast to efficient recombination at mat1, recombination within the adjoining mat2-mat3 interval is undetectable. We defined the role of sequences between mat2 and mat3, designated the K-region, in directionality as well as recombinational suppression. Cloning and sequencing analysis revealed that a part of the K-region is homologous to repeat sequences present at centromeres, which also display transcriptional and recombinational suppression. Replacement of 7.5 kb of the K-region with the ura4+ gene affected directionality in a variegated manner. Analysis of the swi6-mod locus, which was previously shown to affect directionality, in K delta::ura4+ strains suggested the existence of at least two overlapping directionality mechanisms. Our work furthers the model that directionality is regulated by cell-type-specific organization of the heterochromatin-like structure in the mating-type region and provides evidence that the K-region contributes to silencing of the mat2-mat3 interval.
Interaction of Recombinant Norwalk Virus Particles with the 105-Kilodalton Cellular Binding Protein, a Candidate Receptor Molecule for Virus Attachment (2000)

Norwalk virus (NV), responsible for outbreaks of acute gastroenteritis, comprises the species of the genus Norwalk-like viruses in the family Caliciviridae. Although the study of the molecular biology of NV has been hampered by a lack of culture systems or small experimental animal models, virus-like particles (VLPs) generated with recombinant baculoviruses harboring the capsid protein gene of NV provide a useful tool for investigating NV-cell interactions. In this study, the attachment of the recombinant VLPs derived from the Ueno virus (UEV), a strain belonging to the genogroup II NVs, to mammalian and insect cells was examined. Kinetic analyses of the binding of the recombinant VLPs of the UEV (rUEVs) to Caco-2 cells demonstrated that the binding was specific and occurred in a dose-dependent manner. Approximately 7.5% of the prebound rUEVs were internalized into the Caco-2 cells. Enzymatic and chemical modification of Caco-2 cell surface molecules suggested that the binding was directly mediated by a protein-protein interaction. A virus overlay protein-binding assay (VOPBA) indicated that rUEVs appeared to bind to a 105-kDa molecule, designated as the NV attachment (NORVA) protein. Furthermore, the assay indicated that its native conformational structure was indispensable for the binding activity. In Caco-2 cells, the NORVA protein was detected when VOPBA was carried out with the VLPs from Seto and Funabashi viruses, which are serologically different NVs from UEV, used as probes. The binding of rUEVs to NORVA protein was also observed in six mammalian cell lines other than Caco-2. These data suggest that the attachment of NV to mammalian cells is mediated by NORVA protein, which is ubiquitously expressed in the mammalian cells. The present study is the first report on the role of the cellular molecule in the binding of recombinant VLPs of NV.
Cross-linking and characterisation of gelatin matrices for biomedical applications (2000)

Cross-linking of gelatin A and B with N,N-(3-dimethylaminopropyl)-N'-ethyl-carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) was optimised by varying the NHS/EDC molar ratio at constant EDC concentration. Native and cross-linked gelatin gels were characterised using the degree of swelling, the number of free amine groups, the phase transition temperature, and titration of the carboxylic acid residues. The cross-linking reaction was most efficient at a NHS to EDC molar ratio of 0.2. At higher NHS/EDC molar ratios, the reaction of EDC with NHS becomes more pronounced, thereby reducing the effective amount of EDC for cross-linking. Swelling measurements of cross-linked gelatin gels gave deviating results when no NHS was used, which was explained by heterogeneous localisation of cross-links in the gelatin gel. The incorporation of undesired compounds into the gelatin gels during the cross-linking reaction was not observed. At optimal NHS to EDC molar ratio, gelatin A and B were cross-linked using increasing EDC/COOHgelatin molar ratios. A range of samples varying from very low cross-link density to very high cross-link density (at high EDC/COOHgelatin) was obtained. Stability of the gels is enhanced with increasing cross-link density, but a minimal cross-link density is required to obtain gelatin gels which are stable at 40 degrees C.
Three dimensional sub-band coding of video (2003)

A novel coding scheme has been developed which is based on multidimensional subband coding. The digital video signal is filtered and sub-sampled in all three dimensions (temporally, horizontally and vertically) to yield the subbands, from which the input signal can be losslessly reconstructed in the absence of coding loss. The subbands can be more efficiently coded than the input signal in terms of compression and quality, because the restricted information in each band allows well-tailored encoding. The computational complexity of this coding scheme compares favorably to DCT with interframe prediction and inter/intra frame DPCM. The scheme has an architectural structure suitable for parallel implementation, and it yields high compression with sustained good quality.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>
Ultra-low resistance ohmic contacts in graphene field effect transistors (2012)

We report on an experimental demonstration of graphene-metal ohmic contacts with contact resistance below 100 Ω µm. These have been fabricated on graphene wafers, both with and without hydrogen intercalation, and measured using the transmission line method. Specific contact resistivities of 3 × 10−7 to 1.2 × 10−8 Ω cm2 have been obtained. The ultra-low contact resistance yielded short-channel (source-drain distance of 0.45 µm) HfO2/graphene field effect transistors (FETs) with a low on-resistance (Ron) of 550 Ω µm and a high current density of 1.7 A/mm at a source-drain voltage of 1 V. These values represent state-of-the-art (SOA) performance in graphene-metal contacts and graphene FETs. This ohmic contact resistance is comparable to that of SOA high-speed III–V high electron mobility transistors.
Creating a Reactive Enediyne by Using Visible Light: Photocontrol of the Bergman Cyclization (2007)

Visible changes: Visible light is used to create an active enediyne for Bergman cyclization by taking advantage of a well-known molecular photoswitch. Only isomer 2 has the enediyne structure required to produce a diradical that can be trapped as compound 3. Isomer 2 is formed from the thermally stable isomer 1 by stimulating the ring-opening reaction with visible light.
Enhanced excitability of dissociated primary sensory neurons after chronic compression of the dorsal root ganglion in the rat (2004)

A chronic compression of the dorsal root ganglion (CCD) produces ipsilateral cutaneous hyperalgesia and allodynia in rats. Intracellular electrophysiological recordings from formerly compressed neurons in the intact dorsal root ganglion (DRG) reveal lower than normal current thresholds (CTs) and abnormal spontaneous activity (SA) (Zhang JM, Song XJ, LaMotte RH. Enhanced excitability of sensory neurons in rats with cutaneous hyperalgesia produced by chronic compression of the dorsal root ganglion. J Neurophysiol 1999;82:3359-66). To determine if the neuronal hyperexcitability is intrinsic to the soma, L4 and L5 DRG neurons from rats that had prior CCD surgery or those that did not (controls) were dissociated, and intracellular recordings obtained 3-8 h (acute) or 24-30 h (1d) after culture. The CTs of large- (>45 microm diameter) and medium- (30 approximately 45 microm) sized neurons from control rats after acute or 1d culture were similar to those formerly recorded from the intact DRG and significantly lower for CCD than for control rats. However, the CTs of small- (<or=30 microm) sized neurons from control rats were significantly lower in acute or 1d culture groups than they were in the intact DRG and not significantly different from those of dissociated small neurons from CCD rats. The overall incidence of SA was higher for CCD than for control neurons after 1d culture (10.3 vs. 1.8%) and similar to that obtained in the intact DRG. We conclude that the CCD-induced hyperexcitability of medium- and large-sized neurons remains after dissociation and is intrinsic to the soma. For small-sized neurons, the effects of CCD observed in the intact DRG are less apparent after dissociation possibly due to the hyperexcitability produced by the dissociation process itself.
p53 Status and the Efficacy of Cancer Therapy in Vivo (1994)

The therapeutic responsiveness of genetically defined tumors expressing or devoid of the p53 tumor suppressor gene was compared in immunocompromised mice. Tumors expressing the p53 gene contained a high proportion of apoptotic cells and typically regressed after treatment with gamma radiation or adriamycin. In contrast, p53-deficient tumors treated with the same regimens continued to enlarge and contained few apoptotic cells. Acquired mutations in p53 were associated with both treatment resistance and relapse in p53-expressing tumors. These results establish that defects in apoptosis, here caused by the inactivation of p53, can produce treatment-resistant tumors and suggest that p53 status may be an important determinant of tumor response to therapy.
Cytology and immunocytochemistry of bilateral breast metastases from prostatic cancer. Report of a case. (1990)

The cytologic findings in fine needle aspirates of a previously treated prostatic cancer metastatic to both breasts in a 65-year-old man are described. The prostatic origin of the poorly differentiated adenocarcinoma cells was demonstrated by identification of cytoplasmic prostate-specific antigen. The clinical importance of a conclusive diagnosis differentiating a primary from a metastatic lesion is discussed; this case illustrates the value of immunocytochemical analysis as an aid to cytomorphologic diagnosis in making such determinations.
The DNA strand in DNA.cntdot.RNA hybrid duplexes is neither B-form nor A-form in solution (1993)

The structure of the DNA.RNA hybrid (GTCACATG).(caugugac), where lowercase letters designate RNA residues, has been determined on the basis of J-coupling analysis and 2D-NOE studies. The central hexamer in this sequence has been previously studied [Reid, D. G., Salisbury, S. A., Brown, T., Williams, D. H., Vasseur, J.-J., Rayner, B., & Imabach, J.-L. (1983) Eur. J. Biochem. 135, 307-314] via one-dimensional NOE methods and circular dichroism studies. Contrary to their results, we find that this duplex does not assume a B-form conformation in solution. Instead, the RNA residues retain their C3'-endo (A-form) conformation, as indicated by the absence of H1'-H2' couplings and by strong H6/H8 to (n-1) H2'NOEs. The sugars of the DNA residues, on the other hand, do not assume an A-form (or a B-form) conformation but an intermediate conformation in the O4'-endo range (P approximately 72-110 degrees), as indicated by the presence of strong H1'-H4' NOEs, medium-strength H2"-H3' COSY cross peaks, strong H3'-H4' DQF-COSY cross peaks, and H1'-H2' coupling constants that are of approximately the same magnitude as the H1'-H2" coupling constants. These results suggest that the RNA strand not only retains its N-type structure but also exerts an influence on the conformation of the DNA strand. Our results provide strong evidence that DNA.RNA hybrid duplexes do not assume an all-C2'-endo B-type conformation; neither do they assume an all-C3'-endo A-type conformation in solution. Furthermore, although not the main focus of this study, a comparison of the longitudinal relaxation times of the DNA and RNA residues indicates the need for extended relaxation delays in two-dimensional NMR spectra of hybrid duplexes, as has been previously observed for DNA.RNA chimeric duplexes (Wang, A. C., Kim, S.-G., Chou, S.-H., Orban, J., Flynn, P., & Reid, B. R. (1992) Biochemistry 31, 3940-3946).
Therapeutic serum concentrations of human alpha-1-antitrypsin after adenoviral-mediated gene transfer into mouse hepatocytes (1995)

Alpha-1-antitrypsin is a relatively common genetic deficiency that results in early emphysema. The liver as the natural source of most alpha-1-antitrypsin synthesis was the target organ selected for gene replacement therapy studies. Previous work used recombinant retroviral vectors that encode the human alpha-1-antitrypsin cDNA for ex vivo and direct in vivo transduction of hepatocytes in dogs and rodents. This approach led to low levels of human protein in the serum of recipients. In this study, recombinant adenoviral vectors that express the human alpha-1-antitrypsin cDNA under the transcriptional control of the phosphoglycerate kinase (PGK) or RSV-LTR promoters have been constructed and used for the direct transduction of mouse hepatocytes in vivo. The animals transduced with the recombinant adenoviral vectors had therapeutic serum levels of human alpha-1-antitrypsin of up to 700 micrograms/mL. Thus, adenovirus-mediated gene transfer of the hAAT cDNA into the liver was able to produce therapeutic serum concentrations of protein.
Fluorine-enhanced nitridation of silicon at low temperatures in a microwave plasma (1991)

A microwave plasma discharge at very low temperatures (200–250 °C) has been used for the growth of thin silicon oxynitride films suitable for gate dielectric applications. The addition of CHF3 as a source of fluorine enhances the growth rate. A x-ray photoelectron spectroscopy study indicates the incorporation of fluorine (F/Si≂0.2) in the film. Electrical properties of the grown layers have been evaluated by the characterization of metal-insulator-semiconductor capacitors. Results have indicated the presence of negative charges in the insulator. The estimated charge density is lowest for the fluorinated film. The conduction mechanism in the films at room temperature appears to be Frenkel–Poole type.
Polarization-multiplexed rate-adaptive non-binary-quasi-cyclic-LDPC-coded multilevel modulation with coherent detection for optical transport networks (2010)

In order to achieve high-speed transmission over optical transport networks (OTNs) and maximize its throughput, we propose using a rate-adaptive polarization-multiplexed coded multilevel modulation with coherent detection based on component non-binary quasi-cyclic (QC) LDPC codes. Compared to prior-art bit-interleaved LDPC-coded modulation (BI-LDPC-CM) scheme, the proposed non-binary LDPC-coded modulation (NB-LDPC-CM) scheme not only reduces latency due to symbol- instead of bit-level processing but also provides either impressive reduction in computational complexity or striking improvements in coding gain depending on the constellation size. As the paper presents, compared to its prior-art binary counterpart, the proposed NB-LDPC-CM scheme addresses the needs of future OTNs, which are achieving the target BER performance and providing maximum possible throughput both over the entire lifetime of the OTN, better.
Fractal dimension of low-resolution medical images (2002)

Fractal dimension (fd) is a feature which is widely used to characterize medical images. Previously, researchers have shown that fd separates important classes of images and is orthogonal to other texture measures. Existing methods of estimating fd, however, are unable to distinguish many images with similar characteristics, limiting the effectiveness of fd as a feature. This paper analyzes the limitation of box-counting (BC) and fractional Brownian motion (fBm) methods of estimating fd. Estimation by BC is ineffective when applied to data-limited images. Estimation by fBm uses a restrictive model which is not applicable to Iterated Function Systems or to noisy images. The authors present a new method of estimating fd which is applicable to data-limited medical images. In the authors' method, Fractal Interpolation Functions (FIFs) are used to generate self-affine models of graphical representations of image data. The fd of each FIF is analytically evaluated, and measures of confidence and self-affinity are computed. The new method is demonstrated in a test study of red blood cells.
Microfluidics without pumps: reinventing the T-sensor and H-filter in paper networks (2010)

Conventional microfluidic devices typically require highly precise pumps or pneumatic control systems, which add considerable cost and the requirement for power. These restrictions have limited the adoption of microfluidic technologies for point-of-care applications. Paper networks provide an extremely low-cost and pumpless alternative to conventional microfluidic devices by generating fluid transport through capillarity. We revisit well-known microfluidic devices for hydrodynamic focusing, sized-based extraction of molecules from complex mixtures, micromixing, and dilution, and demonstrate that paper-based devices can replace their expensive conventional microfluidic counterparts.
Thrombin is an extracellular signal that activates intracellular death protease pathways inducing apoptosis in model motor neurons (1998)

Apoptosis, often also termed “programmed cell death,” occurs in normal development in the brain and spinal cord. Important to concepts of disease and potential intervention is the exciting finding that apoptosis is also found after neurotrauma and in a number of neurodegenerative diseases. Although the precise mechanism of neuronal cell loss remains unknown, much emphasis has been placed recently on the activation of cell death protease cascades within the cell. How these cascades may be activated, especially from extracellular influences, is currently poorly understood. Thrombin, the multifunctional coagulation protease, is an early phase modulator at sites of tissue injury and has been shown to induce cell death in neurons by an apoptotic mechanism by activating its receptor, PAR-1. Using a model motor neuronal cell line, NSC19, which we have shown undergoes apoptosis after treatment with classic apoptosis inducers such as the topoisomerase inhibitors camptothecin and etoposide, we unambiguously found that nanomolar thrombin induced characteristic signs of apoptosis. Strikingly, endonucleolysis was accompanied by an increase in caspase-3-like activity in cellular extracts, which correlated with both detection of caspase-induced signature cleavage of the cortical cytoskeleton component nonerythroid spectrin (α-fodrin) and identification of increased accessibility of a caspase cleavage domain, using an antibody (Ab127) made against a synthetic peptide KGDEVD. Demonstrating that thrombin activation of death proteases was linked to cell death, we were able to inhibit thrombin-induced apoptosis by using a caspase family inhibitor, benzyloxycarbonyl-Asp-(oMe)-flouromethyl ketone (Boc-D-FMK). These novel results demonstrate that thrombin serves as an extracellular “death signal” to activate intracellular protease pathways. These pathways lead to apoptotic cell death and can be modulated by inhibiting caspase activity downstream to PAR-1. Published 1998 John Wiley & Sons, Inc. J Neurobiol 36: 64–80, 1998 1 This is a US Government work and, as such, is in the public domain in the United States of America.
Cancer Stem Cells: Models and Concepts (2006)

Although monoclonal in origin, most tumors appear to contain a heterogeneous population of cancer cells. This observation is traditionally explained by postulating variations in tumor microenvironment and coexistence of multiple genetic subclones, created by progressive and divergent accumulation of independent somatic mutations. An additional explanation, however, envisages human tumors not as mere monoclonal expansions of transformed cells, but rather as complex tridimensional tissues where cancer cells become functionally heterogeneous as a result of differentiation. According to this second scenario, tumors act as caricatures of their corresponding normal tissues and are sustained in their growth by a pathological counterpart of normal adult stem cells, cancer stem cells. This model, first developed in human myeloid leukemias, is today being extended to solid tumors, such as breast and brain cancer. We review the biological basis and the therapeutic implications of the stem cell model of cancer.
A monopole loaded with a loop antenna (1996)

A traveling-wave distribution of current can be produced on a monopole over a ground plane by inserting a resistance of suitable magnitude one-quarter wavelength from its end. It has been shown that the resistor can be replaced with a modified folded dipole which has a radiation resistance approximately equal to that of the resistor. In this paper, the resistor is replaced with a loop antenna. The main objective is to obtain an antenna having hemispherical coverage and is circularly polarized. Input impedance, current distribution, and radiation patterns of this antenna are computed using the numerical electromagnetics code (NEC); radiation patterns are also measured. Monopoles which are loaded with both series and parallel-fed circular and square loops are investigated. It was shown that circular polarization could be obtained over most of the hemisphere with both types of series-fed loops. The parallelized loop insertions produced more directional circularly polarized patterns. Most computations and measurements were made at a frequency of 1.6 GHz. The frequency dependence was examined and it was found that these antennas can operate over the band from 1.4-2.0 GHz. These very simple, low-cost antennas have potential application for systems such as IRIDIUM and Global Positioning System.
An Improved Acid Chloride Preparation via Phase Transfer Catalysis (1991)

Phase transfer catalysis has been found to be effective for the rapid conversion of carboxylic acids in high yield to the corresponding acid chlorides. The procedure is well suited for acids that exhibit low solubilities in normal organic solvents.
CXC.—Harmine and harmaline. Part I (1912)

W. H. Perkin and R. Robinson, J. Chem. Soc., Trans., 1912, 101, 1775 DOI: 10.1039/CT9120101775