gebhart/patrepeval huggingface dataset:
Nuclear Magnetic Resonance Spectroscopic and Principal Components Analysis Investigations into Biochemical Effects of Three Model Hepatotoxins (1998)

1H NMR spectroscopy of urine combined with pattern recognition (PR) methods of data analysis has been used to investigate the time-related biochemical changes induced in Sprague-Dawley rats by three model hepatotoxins: alpha-naphthyl isothiocyanate (ANIT), d-(+)-galactosamine (GalN), and butylated hydroxytoluene (BHT). The development of hepatic lesions was monitored by conventional plasma analysis and liver histopathology. Urine was collected continuously postdosing up to 144 h and analyzed by 600-MHz 1H NMR spectroscopy. NMR spectra of the urine samples showed a number of time-dependent perturbations of endogenous metabolite levels that were characteristic for each hepatotoxin. Biochemical changes common to all three hepatotoxins included a reduction in the urinary excretion of citrate and 2-oxoglutarate and an increased excretion of taurine and creatine. Increased urinary excretion of betaine, urocanic acid, tyrosine, threonine, and glutamate was characteristic of GalN toxicity. Both GalN and ANIT caused increased urinary excretion of bile acids, while glycosuria was evident in BHT- and ANIT-treated rats. Data reduction of the NMR spectra into 256 integrated regions was used to further analyze the data. Mean values of each integrated region were analyzed by principal components analysis (PCA). Each toxin gave a unique time-related metabolic trajectory that could be visualized in two-dimensional PCA maps and in which the maximum distance from the control point corresponded to the time of greatest cellular injury (confirmed by conventional toxicological tests). Thereafter, the metabolic trajectories changed direction and moved back toward the control region of the PR map during the postdose recovery phase. The combination of urinary metabolites which were significantly altered at various time points allowed for differentiation between biliary and parenchymal injury. This NMR-PR approach to the noninvasive detection of liver lesions will be of value in furthering the understanding of hepatotoxic mechanisms and assisting in the discovery of novel biomarkers of hepatotoxicity.
Cloning with tandem gene systems for high level gene expression (1984)

A method has been devised for increasing the copy number of a gene (or genes) cloned into a plasmid while minimizing the size of the plasmid. If n copies of a transcriptional unit are cloned, including the promoter, coding region and terminator, the size of the plasmid will increase by n times the total size of the unit. However, if we borrow the concept of polycistronic operon and sandwich n structural genes, each with its own ribosome binding-site, between a promoter and a transcription terminator, there will be a space saving equivalent to n-1 promoters and n-1 transcription terminators. We have constructed plasmids in which an E. coli lipoprotein promoter is followed by 1 to 4 human leukocyte interferon genes and a transcription terminator. The applications of this method in genetic engineering are discussed.
Studies on the chlorinating activity of myeloperoxidase. (1976)

Two methods were utilized to demonstrate the peroxidation of chloride ion to a free species (HOCl or Cl2) by myeloperoxidase. The peroxidase caused the volatilization of radioactivity from soultions containing hydrogen peroxide and [36Cl]NaCl, and catalyzed the formation of HOCl when solutions contianing these components were passed through a Millipore filter to which the peroxidase was adsorbed. In this flow system, 90 mug of canine myeloperoxidase generated 80 muM HOCl in the presence of 200 muM H2O2 at a rate corresponding to a turnover of 100 min-1. Under these conditions, o-tolidine, whose oxidation can be coupled to Cl- peroxidation in free solution, did not accelerate turnover. In contrast to chloroperoxidase and horseradish peroxidase, myeloperoxidase does not utilize chlorite for chlorination reactions. This oxidant inactivates the enzyme. At low pH, chloride ion suppresses the oxidation of myeloperoxidase (to the stable compound II) by both hydrogen peroxide and hypochlorite. Acceptor chlorination is therefore not a rate-controlling reaction in the myeloperoxidase mechanism, and the potential of the functional peroxidase couple is higher than the HOCl/Cl- couple under chlorinating conditions. The product-forming step may be a reverse of compound I formation at the expense of HOCl, rather than the chlorination of Cl- by a chloroperoxidase-like chlorinating intermediate.
Steric stabilization of phospholipid vesicles by block copolymers Vesicle flocculation and osmotic swelling caused by monovalent and divalent cations (1998)

Steric stabilization of small unilamellar phospholipid vesicles (liposomes) following conjugation of (tri-)block copolymer molecules by physical means can be carried out either by allowing the copolymer molecules to participate in vesicle bilayer formation, or by adsorbing the copolymers onto preformed liposome surfaces. These systems and a bare liposome system have been compared. The degree of steric stability was determined relative to vesicle resistance against flocculation and osmotic swelling induced by cations. The pronounced affinity of monovalent (Na+) and divalent (Mn2+) cations for the phospholipid surface was exploited to cause flocculation of the vesicle dispersions. Moreover, the formation of an osmotic gradient by varying the electrolyte concentration in the outer and inner vesicle aqueous phases was used to produce swollen liposomes. Size determination by quasi-elastic light scattering (QUELS), surface characterization by laser Doppler electrophoresis (LDE), turbidity measurement by UV–VIS spectroscopy, NMR measurements and phase contrast video-microscopy were used to characterize and compare the vesicle systems. In both ways of copolymer addition the large hydrophilic polymer chains coat the phospholipid surface, as manifested by the considerable resistance to cation-induced flocculation. The presence of polymer at the vesicle surface offers increased protection, owing to the repelling forces due to polymeric steric barriers acting on vesicle close contact. Only the vesicles formed in the presence of copolymer molecules exhibited inert behaviour to osmotic swelling, confirming the alteration of the bilayer structure and its related properties. The advantages of constructing sterically stabilized vesicles by allowing the hydrophobic block of the copolymer to form an integral part of the bilayer are thus evident, since a robust surface coating is achieved by firmly anchored copolymer molecules rather than surface-adsorbed polymers, while avoiding the costly cumbersome chemical modification process of attaching polymer chains onto lipid headgroups.
Potential new strategies for the treatment of ovarian infertility and degenerative diseases with autologous ovarian stem cells (2006)

The 50-year-old and currently prevailing view that all oocytes in adult human ovaries persist from the fetal period of life is controversial as it clashes with Darwinian evolutionary theory. Studies of oogenesis and follicular renewal in adult human ovaries, and of the role of hormonal signals and third-party cells (tissue macrophages and T cells), could all be helpful in providing better understanding of the causes of ovarian infertility, its prevention and potential therapy. In addition, the authors recently reported differentiation of distinct cell types and the production of new eggs in cultures derived from premenopausal and postmenopausal human ovaries. It is possible that fertilisation of such eggs will open up new opportunities for providing genetically related children to infertile women for whom conventional in vitro fertilisation has failed. As ovarian stem cells appear to represent a new type of totipotent adult stem cell, they could also be utilised for autologous stem cell therapy of degenerative diseases, without any involvement of allogeneic embryonic stem cells and somatic cell nuclear transfer.
Electrophoretic comparison of Dendroctonus punctatus LeConte and D. micans (Kugelann) (Coleoptera: Scolytidae) (1997)

(Uploaded by Plazi from the Biodiversity Heritage Library) No abstract provided.
Cloning of the alpha chain of human platelet glycoprotein Ib: a transmembrane protein with homology to leucine-rich alpha 2-glycoprotein. (1987)

Glycoprotein Ib is a surface membrane glycoprotein of platelets that functions as a receptor for von Willebrand factor. It is a heterodimer composed of an alpha and a beta chain linked by a disulfide bond(s). A phage lambda gt11 cDNA expression library prepared from mRNA from a human erythroleukemia cell line, HEL, was screened using an affinity-purified antibody to the glycocalicin portion of the alpha chain of glycoprotein Ib. Eleven positive clones were isolated and plaque-purified. The largest cDNA insert was 2420 nucleotides in length and coded for a leader sequence of 16 amino acids, a mature protein of 610 amino acids, and a stop codon. It also contained 42 nucleotides of 5' noncoding sequence and 497 nucleotides of 3' noncoding sequence, including a poly(A) tail. The amino acid sequence of the alpha chain of GPIb predicted from the cDNA agreed completely with the sequence of 156 amino acids that was determined by Edman degradation of peptides isolated from human platelet glycocalicin after digestion with trypsin or Staphylococcus aureus V8 protease. The extracytoplasmic domain of the alpha subunit of GPIb contains several noteworthy structural features, including a region of seven tandem repeats of 24 amino acids that are homologous with those present in leucine-rich alpha 2-glycoprotein. The extracytoplasmic domain also contains two hydrophilic regions, one rich in charged amino acids and a second rich in serine and threonine residues. The region rich in serine and threonine includes five repeats of nine amino acids as well as the majority of the O-linked carbohydrate sites present in the molecule. The extracytoplasmic domain is followed by a potential transmembrane segment of approximately 29 amino acids and a potential intracellular domain of approximately 100 amino acids located at the carboxyl end of the molecule.
Function, mechanism and regulation of bacterial ribonucleases (1999)

The maturation and degradation of RNA molecules are essential features of the mechanism of gene expression, and provide the two main points for post-transcriptional regulation. Cells employ a functionally diverse array of nucleases to carry out RNA maturation and turnover. Viruses also employ cellular ribonucleases, or even use their own in their reproductive cycles. Studies on bacterial ribonucleases, and in particular those from Escherichia coli, are providing insight into ribonuclease structure, mechanism, and regulation. Ongoing biochemical and genetic analyses are revealing that many ribonucleases are phylogenetically conserved, and exhibit overlapping functional roles and perhaps common catalytic mechanisms. This article reviews the salient features of bacterial ribonucleases, with a focus on those of E. coli, and in particular, ribonuclease III. RNase III participates in a number of RNA maturation and RNA decay pathways, and is regulated by phosphorylation in the T7 phage-infected cell. Plasmid and phage RNAs, in addition to cellular transcripts, are RNase III targets. RNase III orthologues occur in eukaryotic cells, and play key functional roles. As such, RNase III provides an important model with which to understand mechanisms of RNA maturation, RNA decay, and gene regulation.
Acoustic virtual reality performing man-machine interfacing of the blind (2008)

Abstract:- In this paper, a man-machine interface included in an integrated environment that improves the mobility of blind persons into a limited area is presented. The proposed solution relies on the Acoustic Virtual Reality (AVR) concept, which can be considered as a substitute for the lost sight of blind and visually impaired individuals. According to the AVR concept, the presence of obstacles in the surrounding environment and the path to the target will be signalized to the subject by burst of sounds, whose virtual source position suggests the position of the real obstacles and the direction of movement, respectively. After a brief presentation of the AVR concept, the paper is focused on the implementation of the proposed man-machine interface, based on this new concept and the status of the research. Finally, some conclusions and further developments are also presented. Key-Words:- visually impaired individuals, electronic travel aid, man-machine interface, acoustic virtual reality. 1
Preview-Based Optimal Inversion for Output Tracking: Application to Scanning Tunneling Microscopy (2004)

Optimal inversion of system dynamics can be used to design inputs that achieve precision output tracking. However, a challenge in implementing the optimal-inversion approach is that the resulting inverse input tends to be noncausal. The noncausality of the optimal inverse implies that the desired output trajectory must be pre-specified and cannot be changed online. Therefore, the optimal inverse can only be used in trajectory-planning applications (where the desired output is known in advance for all future time). The main contribution of this article is the development of a technique to compute the noncausal optimal inverse when the desired output trajectory is known in advance for only a finite time interval. This future time interval, during which the desired output trajectory is specified, is referred to as the preview time. Additionally, this article develops a time-domain implementation of the optimal inverse and quantifies the required preview time in terms of the specified accuracy in output tracking, the system dynamics, and the cost function used to develop the optimal inverse. The proposed approach is applied to precision (subnanoscale) positioning of a scanning tunneling microscope (STM), which is a key enabling tool in emerging nanotechnologies. Experimental results are presented which show that finite preview of the desired output trajectory is sufficient to operate the STM at high speeds.
Kinetic and spectroscopic studies of haemoglobin and myoglobin from Urechis caupo. Distal residue effects (1990)

Seven components of the tetrameric haemoglobin (Hbu) from Urechis caupo were separated by preparative isoelectric focusing and characterized by their absorption spectra and pI values. The helix content and Soret delta epsilon values are reported for several of the components. Temperature-jump O2-binding kinetics of the major components of Hbu show biphasic behaviour, with the majority species having kon = 1.57 x 10(9) mol-1.s-1 and koff = 3.32 x 10(4) s-1. The Fourier-transform i.r. spectrum of pooled Hbu(II)-CO displays a stretching frequency of 1942 cm-1. E.s.r. of Hbu(II)-NO demonstrates evidence of proximal strain similar to that encountered in T-state human haemoglobin. CO-driven reduction of U. caupo methaemoglobin, Hbu(III) and U. caupo metmyoglobin [Mbu(III)] shows much higher rates relative to haemoglobins and myoglobins known to possess a distal histidine residue. Nitrosyl auto-reduction kinetics of Hbu(III)-NO and Mbu(III)-NO are examined. The equilibrium binding constants of several ligands are reported for both Hbu and Mbu, and together with the above kinetic data suggest differences in haem pocket environments between Hbu and Mbu. Reaction of Hbu with 2-chloromercuri-4,6-dinitrophenol demonstrates the presence of one reactive thiol group per globin chain. lambda max. values and the respective molar absorption coefficients for selected ligand-bound states are reported for the major component of Hbu and for Mbu. The majority haem orientation in U. caupo haemoglobin is identical with that of human haemoglobin.
Monoclonal antibodies to nerve growth factor affect the postnatal development of the visual system. (1994)

Exogenous supply of nerve growth factor (NGF) prevents the effects of monocular deprivation. This suggests that visual afferents may be competing for an endogenous neurotrophic factor, related to NGF, whose production by postsynaptic cells depends on the activity of afferent fibers. To test the hypothesis that endogenous NGF may play a role in the functional and anatomical development of the rat geniculo cortical system, the physiological action of NGF in the rat visual system was antagonized by using two independent monoclonal antibodies which neutralize NGF (alpha D11 and 4C8). To provide a continuous supply of antibodies during the period of visual cortical plasticity, alpha D11 or 4C8 antibody-producing hybridoma cells were implanted in the lateral ventricle of rats at postnatal day 15. This resulted in dramatic alterations of two of the most important parameters characterizing the functional development of the visual system, namely, visual acuity and binocularity of cortical neurons and in shrinkage of cells in the lateral geniculate nucleus. This demonstrates that the action of endogenous NGF is necessary for the normal functional and anatomical development of the geniculocortical system.
New hydrogen carbonate precursors for efficient and byproduct-free syntheses of ionic liquids based on 1,2,3-trimethylimidazolium and N,N-dimethylpyrrolidinium cores (2010)

Two new hydrogen carbonate IL precursors, 1,2,3-trimethylimidazolium and N,N-dimethylpyrrolidinium hydrogen carbonate salts, were synthesized and their structures confirmed by NMR and single-crystal X-ray diffraction. These salts were also evaluated for application in the syntheses of ILs by reacting them with a variety of acids and [NH4][ClO4], which resulted in the clean and quantitative formation of a family of 1,2,3-trimethylimidazolium- and N,N-dimethylpyrrolidinium-based salts. Synthetic protocols for the formation of the hydrogen carbonate salts involved simple alkylation reactions of the chosen neutral amines with dimethyl carbonate, and later conversion of the formed methyl carbonate anion-based salts to hydrogen carbonate salts. The reactions proceed in one step at temperatures close to room temperature using only water. The new organic salts with the chosen anions are formed with only gaseous byproducts (CO2, H2O, and in the case of [NH4][ClO4], NH3), thus eliminating further purification steps. This generalized synthetic protocol for the formation of hydrogen carbonate IL precursors may be used as a cleaner, contaminant-free (halides and metal ions) route to many classes of ILs.
Improved Targeting of Pancreatic Cancer (2004)

These studies demonstrate the feasibility of using the pretargeted, bispecific antibody technology for nuclear imaging of pancreatic cancer. The advantage of pretargeted bsPAM4 antibody as an imaging platform is the high specificity for pancreatic cancer as compared with the physicochemical parameters identified by current imaging technologies.
Assay for the Measurement of Copeptin, a Stable Peptide Derived from the Precursor of Vasopressin (2005)

Copeptin is stable for days after blood withdrawal and can be quickly and easily measured. The copeptin assay may be a useful alternative to direct measurement of AVP concentration.
Distributed measurement and control based on the IEEE 1451 smart transducer interface standards (2000)

This paper details a framework developed at NIST that highlights the standardization efforts going on within the various levels of an Internet-based distributed measurement and control (DMC) system. The framework highlights state-of-the-art hardware and software techniques used at NIST to design, implement, and deploy next-generation Internet-based DMC applications and systems. The framework targets three important areas of standardization including transducer interfaces, open network communication, and distributed application development. An implementation of a DMC application on the Internet based on the NIST framework is also described. The paper concludes with a brief introduction to other research activities at NIST culminating from this core Internet-based DMC research.
Synthesis of the infectious pancreatic necrosis virus polyprotein, detection of a virus-encoded protease, and fine structure mapping of genome segment A coding regions (1987)

Full-length and truncated genome segment A-specific infectious pancreatic necrosis virus cDNA was subcloned into plasmid transcription vectors, and runoff transcripts were produced in vitro. These transcripts were translated in cell-free rabbit reticulocyte lysates and the translation products were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Virus-specific polypeptides were gel purified and mapped by partial proteolysis with N-chlorosuccinimide and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Peptide profiles were compared with those of the corresponding polypeptides purified from infectious pancreatic necrosis virus-infected cells or prepared by in vitro translation of denatured genomic RNA. The cDNA directed the synthesis of authentic pVP2, VP3, and NS polypeptides as well as a number of previously undescribed polypeptides. A 101,000-molecular-weight polypeptide was isolated and shown to be the unprocessed infectious pancreatic necrosis virus polyprotein. The NS polypeptide appears to be a virus-encoded protease responsible for the cleavage of pVP2 from the polyprotein. The carboxy terminus of NS was mapped to within three or four amino acids on the polyprotein. The most likely internal translation start sites responsible for NS and VP3 production in vitro were also mapped.
Measuring Platelet Aggregation with Microplate Reader: A New Technical Approach to Platelet Aggregation Studies (1990)

Platelet aggregation measurements were done with the use of a commercially available microtiter plate reader with specific modification of the mode of agitation of the samples. Satisfactory aggregation curves were obtained with use of an external horizontal agitator, with an amplitude of 1.3 mm and minimum frequency of 1,360 cycles/minute. With the use of the 96 available wells in the microtiter plates, all test and control platelet samples, with replicates, were observed simultaneously and the output data obtained within 10-15 minutes. The technique was validated by demonstrating the similarity of dose-response curves, obtained with a standard aggregometer and with the microtiter technique, of platelets stimulated by adenosine diphosphate, thrombin, and arachidonic acid.