gebhart/patrepeval huggingface dataset:
Synaptic transfer of rod signals to horizontal and bipolar cells in the retina of the toad (Bufo marinus). (1988)

1. Simultaneous intracellular recordings of responses to light flashes were obtained from rod-horizontal cell and rod-hyperpolarizing bipolar cell pairs in isolated retinae of the toad. The gain and temporal filtering of synaptic transfer were characterized throughout the rods' range of light responses. 2. Paired rod-horizontal cell and rod-bipolar cell responses to dim flashes (less than 0.4 Rh*, where Rh* denotes effective photoisomerizations per rod per flash) exhibited nearly the same time course. Analysis of the onset of the horizontal cell responses revealed a temporal lag equivalent to a single stage of low-pass filtering (tau f = 75-200 ms). No filtering was discerned in the transfer of dim-flash responses from rods to bipolars. On average, horizontal cells were five times as sensitive (mV/Rh*) and hyperpolarizing bipolar cells 10.7 times as sensitive as their paired rods. 3. For brighter flashes, up to 1600 Rh*, the rising and return phases of bipolar responses appeared to be simple scaled versions of the rod responses. The scaling factor was equal to the ratio of flash sensitivities for dim flashes. Rod responses greater than about 2 mV produced a saturation of the bipolar cell response. 4. The return phases of the horizontal cell responses were kinetically similar, scaled versions of the rod responses for rod potentials less than about 5 mV. However, the rising phases lagged significantly behind those of the rod. The effective time constant of the lag increased proportionally with flash intensity. For the brighter flashes, the horizontal cell response peaked as much as a second after the rod response. 5. The linear scaling, minimal temporal filtering and saturation of the bipolar cell responses were satisfactorily reproduced by a model of synaptic transfer that assumed that the rate of transmitter release followed the rod voltage exponentially and that the postsynaptic conductance followed Michaelis-Menten saturation (Falk & Fatt, 1972). 6. The progressively longer lag in the horizontal cell responses to brighter flashes was satisfactorily simulated by a kinetically limited Falk and Fatt model which postulated that the effective electrical time constant of the horizontal cell membrane strongly depended on synaptic or voltage-modulated conductances. 7. Satisfactory model simulations of all postsynaptic responses required that an e-fold change in the release rate of transmitter from the rod be obtained with a 2 mV change in the rod potential.
[Research progress of biological characteristics and advantages of Wharton's jelly-mesenchymal stem cells]. (2011)

WJ-MSCs have numerous advantages of convenient and abundant sources, relatively pure, non-ethical issues, and so on, which can be used for cell transplant therapy, gene therapy, and the ideal seed cells of building tissue engineered organ, so they provide new ideas for tissue regeneration repair and reconstruction.
A Study of Slip/Stick Motion of the Bit (1988)

Summary This paper deals with torsional oscillations caused by slip/stick motion of the drill-collar section. This phenomenon is associated with a large-amplitude, saw-tooth-like variation in the applied torque. "Slip/stick motion" refers to the belief that the amplitude of the torsional oscillations becomes so large that the drill-collar section periodically comes to a complete stop and does not come free until enough torque is built up in the drillstring to overcome the static friction. A mathematical model of slip/stick motion is presented. This model includes parameters describing downhole friction effects and a simplified description of the drillstring. The effects of damping, finite rotary-table inertia, and the rotary-speed control system are discussed. Theoretical predictions are compared with measured torque signals recorded during field drilling. This kind of drilling performance is likely to be less effective than normal drilling and may also lead to fatigue problems. This paper discusses ways to avoid severe torsional oscillations by using a more sophisticated feedback system to control the rotary speed.
Beam tests on a proton linac booster for hadron therapy (2002)

LIBO is a 3 GHz modular side-coupled proton linac booster designed to deliver beam energies up to 200 MeV, as required for the therapy of deep seated tumours. The injected beam of 50 to 70 MeV is produced by a cyclotron like those in several hospitals and research institutes. A full-scale prototype of the first module with an input/output energy of 62/74 MeV, respectively, was designed and built in 1999 and 2000. Full power RF tests were carried out successfully at CERN using a test facility at LIL at the end of the year 2000. In order to prove the feasibility of the acceleration process, an experimental setup with this module was installed at the INFN Laboratorio Nazionale del Sud (LNS) in Catania during 2001. The superconducting cyclotron provided the 62 MeV test beam. A compact solid-state RF modulator with a 4 MW klystron, made available by IBA-Scanditronix, was put into operation to power the linac. In this paper the main features of the accelerator are reviewed and the experimental results obtained during the first beam acceleration tests are presented. (3 refs).
Licensing digital content with a generic ontology (2007)

Digital contents distributed over the internet are regulated by law and by technical management systems. The latter include a semantic component that describes licenses, i.e. rights of use which are granted to the user. These elements of Digital Rights Management (DRM) systems are called Rights Expression Languages (REL), they gather terms and relations needed to build licenses. Some are based on an ontology of online licenses, not necessarily related to applicable law and various legal systems, and cannot interoperate. As a consequence, there is a need for a more generic way to express licenses. Here, generic means that rightholders should only need to express the license they need once, and semi-automatic tools should then translate this license so it can be browsed by any specific system. Hence it implies the necessity to be able to model concept semantics in order to translate a license expressed in generic terms into more specific terms that are compliant with the specific standards used by distribution systems. This work comes as part of larger studies on legal ontologies, legal systems and RELs.
A new polymerization method and kinetics for acrylamide: Aqueous two‐phase polymerization (2008)

Abstract The concept of aqueous two‐phase polymerization and a new polymerization method for the preparation of water‐soluble polymers are presented. The phase diagram of poly(acrylamide) (PAAm)‐poly (ethylene glycol) (PEG)‐water two‐phase system was measured by the gel permeation chromatography (GPC). The aqueous two‐phase of PAAm‐PEG‐water system can be easily formed. The critical concentration of phase separation was affected by the molecular weight of PEG. The aqueous two‐phase polymerization of acrylamide (AAm) has been successfully carried out in the presence of PEG by using ammonium persulfate (APS) as the initiator. The polymerization behaviors with varying concentration of AAm, initiator and PEG, the polymerization temperature, the molecular weight of PEG, and emulsifier types were investigated. The activation energy of aqueous two‐phase polymerization of AAm was 132.3 kJ/mol. The relationship of initial polymerization rate ( R p 0 ) with APS and AAm concentrations was R p 0 ∝ [APS] 0.72 [AAm] 1.28 . © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Step by Step (2007)

Proton pumps produce electrical potential differences and differences in pH across the plasma membrane of cells which drive secondary ion transport through sym- and antiporters. We used the patch-clamp technique to characterize an H(+)-pump in the xylem parenchyma of barley roots. This cell type is of special interest with respect to xylem loading. Since it has been an ongoing debate whether xylem loading is a passive or an active process, the functional characterization of the H(+)-pump is of major interest in the context of previous work on ion channels through which passive salt efflux into the xylem vessels could occur. Cell-type specific features like its Ca(2+) dependence were determined, that are important to interpret its physiological role and eventually to model xylem loading. We conclude that the electrogenic pump in the xylem parenchyma does not participate directly in the transfer of KCl and KNO(3) to the xylem but, in combination with short-circuiting conductances, plays a crucial role in controlling xylem unloading and loading through modulation of the voltage difference across the plasma membrane. Here, our recent results on the H(+) pump are put in a larger context and open questions are highlighted.
Selective Lateral Germanium Growth for Local GeOI Fabrication (2014)

High quality local Germanium-on-oxide (GeOI) wafers are fabricated using selective lateral germanium (Ge) growth technique by a single wafer reduced pressure chemical vapor deposition system. Mesa structures of 300 nm thick epitaxial silicon (Si) interposed by SiO2 cap and buried oxide are prepared. HCl vapor phase etching of Si is performed prior to selective Ge growth to remove a part of the epitaxial Si to form cavity under the mesa. By following selective Ge growth, the cavity was filled. Cross section TEM shows dislocations of Ge which are located near Si / Ge interface only. By plan view TEM, it is shown that the dislocations in Ge which direct to SiO2 cap or to buried-oxide (BOX) are located near the interface of Si and Ge. The dislocations which run parallel to BOX are observed only in [110] and [1–10] direction resulting Ge grown toward [010] direction contains no dislocations. This mechanism is similar to aspect-ratio-trapping but here we are using a horizontal approach, which offers the option to remove the defective areas by standard structuring techniques. A root mean square of roughness of ∼0.2 nm is obtained after the SiO2 cap removal. Tensile strain in the Ge layer is observed due to higher thermal expansion coefficient of Ge compared to Si and SiO2.
Temperature influence on the dynamics of vertically aligned liquid crystal displays (2008)

The strong influence of the complex reverse flow phenomenon on the dynamic temperature behavior of vertically aligned liquid crystal displays (VA-LCDs) has been demonstrated. Good agreement was obtained between theoretical and experimental switching profiles over a wide temperature range (25–75°C). This was achieved using the Leslie–Ericksen theory in a one-dimensional model with material viscosity coefficients obtained from an improved estimation procedure. Such accurate numerical simulations can have a large impact on further improvements of VA-LCDs (e.g., the development of temperature-compensating driving schemes).
Interactive and anisotropic geometry processing using the screened Poisson equation (2011)

We present a general framework for performing geometry filtering through the solution of a screened Poisson equation. We show that this framework can be efficiently adapted to a changing Riemannian metric to support curvature-aware filtering and describe a parallel and streaming multigrid implementation for solving the system. We demonstrate the practicality of our approach by developing an interactive system for mesh editing that allows for exploration of a large family of curvature-guided, anisotropic filters.
Hesperetin Modifies the Composition of Fecal Microbiota and Increases Cecal Levels of Short-Chain Fatty Acids in Rats (2015)

There has been particular interest in the prebiotic-like effects of commonly consumed polyphenols. This study aimed to evaluate the effects of hesperidin (HD) and its aglycone hesperetin (HT), major flavonoids in citrus fruits, on the structure and activity of gut microbiota in rats. Rats ingested an assigned diet (a control diet, a 0.5% HT diet, or a 1.0% HD diet) for 3 weeks. Terminal restriction fragment length polymorphism analysis revealed that the proportion of Clostridium subcluster XIVa in the feces collected at the third week of feeding was significantly reduced by the HT diet: 19.8 ± 4.3% for the control diet versus 5.3 ± 1.5% for the HT diet (P < 0.01). There was a significant difference in the cecal pool of short-chain fatty acids (SCFA), the sum of acetic, propionic, and butyric acids, between the control diet (212 ± 71 μmol) and the HT diet (310 ± 51 μmol) (P < 0.05), whereas the HD diet exhibited no effects (245 ± 51 μmol). Interestingly, dietary HT resulted in a significant increase in the excretion of starch in the feces. HT, but not HD, might reduce starch digestion, and parts of undigested starch were utilized to produce SCFA by microbial fermentation in the large intestine.
A technique for extracting physiological parameters and the required input function simultaneously from PET image measurements: theory and simulation study (1997)

Positron emission tomography (PET) is an important tool for enabling quantification of human brain function. However, quantitative studies using tracer kinetic modeling require the measurement of the tracer time-activity curve in plasma (PTAC) as the model input function. It is widely believed that the insertion of arterial lines and the subsequent collection and processing of the biomedical signal sampled from the arterial blood are not compatible with the practice of clinical PET, as it is invasive and exposes personnel to the risks associated with the handling of patient blood and radiation dose. Therefore, it is of interest to develop practical noninvasive measurement techniques for tracer kinetic modeling with PET. In this paper, a technique is proposed to extract the input function together with the physiological parameters from the brain dynamic images alone. The identifiability of this method is tested rigorously by using Monte Carlo simulation. The results show that the proposed method is able to quantify all the required parameters by using the information obtained from two or more regions of interest (ROI's) with very different dynamics in the PET dynamic images. There is no significant improvement in parameter estimation for the local cerebral metabolic rate of glucose (LCMRGlc) if the number of ROI's are more than three. The proposed method can provide very reliable estimation of LCMRGlc, which is our primary interest in this study.
Comparative Efficacy Evaluation of Dicationic Carbazole Compounds, Nitazoxanide, and Paromomycin against <i>Cryptosporidium parvum</i> Infections in a Neonatal Mouse Model (1998)

The efficacies of dicationic carbazole compounds, nitazoxanide (NTZ), and paromomycin were evaluated against the AUCp1 isolate of Cryptosporidium parvum by using a neonatal mouse model. Compounds were solubilized or suspended in deionized water and administered orally by gavage to neonatal mice at a constant dose rate on days 0 to 5 (treatment started on day 0). Dose rates varied for individual carbazole compounds but ranged from 0.65 to 20 mg/kg of body weight. NTZ was tested at 100 and 150 mg/kg, and paromomycin was tested at 50 mg/kg. Efficacies were determined by comparing numbers of oocysts present in treated versus control mice at necropsy examination on day 6. Demonstrable efficacy was observed for several carbazole compounds, based on significant reductions in the numbers of oocysts recovered from treated mice versus control mice. Compounds 1, 7, and 10 (19.0 mg/kg) reduced oocyst passage in treated mice to less than 5% of that in control mice. Treatment with compounds 6, 8, and 9 (17.0 mg/kg) resulted in reductions of oocyst output to less than 10% of that in controls. Although they were not comparable in efficacy to compounds 1, 6, 7, 8, 9, and 10, treatment with other carbazole compounds resulted in statistically significant reductions in oocyst output in treated versus control mice. Compound 1 retained efficacy resulted in reduction of oocyst output to approximately 6% of that in controls when the dose was reduced to 5 mg/kg. Further reductions in the dose rate resulted in considerable reductions in anticryposporidial activity. Likewise, the efficacies of compounds 9 and 10 were reduced substantially when the doses were lowered to one-half the screening dose. Paromomycin yielded excellent activity (reduction of oocyst output to <2% of that in controls) at a dose of 50 mg/kg. NTZ yielded moderate efficacy as powder and injectable formulations administered at 100 mg/kg orally (reduction of oocyst output to 42 and 26% of that in controls, respectively). Oral administration of the injectable formulation of NTZ at a dose of 150 mg/kg resulted in improved efficacy (oocyst output, <5% of that in controls).
Patients with an inherited syndrome characterized by immunodeficiency, microcephaly, and chromosomal instability: genetic relationship to ataxia telangiectasia. (1988)

Fibroblast cultures from six unrelated patients having a familial type of immunodeficiency combined with microcephaly, developmental delay, and chromosomal instability were studied with respect to their response to ionizing radiation. The cells from five of them resembled those from individuals with ataxia telangiectasia (AT) in that they were two to three times more radiosensitive on the basis of clonogenic cell survival. In addition, after exposure to either X-rays or bleomycin, they showed an inhibition of DNA replication that was less pronounced than that in normal cells and characteristic of AT fibroblasts. However, the patients are clinically very different from AT patients, not showing any signs of neurocutaneous symptoms. Genetic complementation studies in fused cells, with the radioresistant DNA synthesis used as a marker, showed that the patients' cells could complement representatives of all presently known AT complementation groups. Furthermore, they were shown to constitute a genetically heterogeneous group as well. It is concluded that these patients are similar to AT patients with respect to cytological parameters. The clinical differences between these patients and AT patients are a reflection of genetic heterogeneity. The data indicate that the patients suffer from a chromosome-instability syndrome that is distinct from AT.
Three-level neutral-point-clamped matrix converter topology (2009)

Matrix converter is a direct AC-AC converter topology that is able to directly convert energy from an AC source to an AC load without the need of a bulky and limited lifetime energy storage element. Due to the significant advantages offered by matrix converter, such as adjustable power factor, capability of regeneration and high quality sinusoidal input/output waveforms, matrix converter has been one of the AC – AC topologies that receive extensive research attention for being an alternative to replace traditional AC-DC-AC converters in the variable voltage and variable frequency AC drive applications. \n\nMultilevel matrix converter is an emerging topology that integrates the multilevel concept into the matrix converter topology. Having the ability to generate multilevel output voltages, the multilevel matrix converter is able to produce better quality output waveforms than conventional matrix converter in terms of harmonic content, but at the cost of higher number of power semiconductor device requirement and more complicated modulation strategy.\n\nIn this research work an indirect three-level sparse matrix converter is proposed. The proposed converter is a hybrid combination between a simplified three-level neutral-point-clamped voltage source inverter concept and an indirect matrix converter topology. This multilevel matrix converter topology has a simpler circuit configuration and is able to generate three-level output voltages, making this topology an attractive option in industrial applications.\n\nIn this work a comprehensive simulation study is carried out to investigate the operation of the proposed converter. The performance of the proposed converter is compared to the conventional indirect matrix converter topology and a multilevel neutral-point- clamped matrix converter in order to identify the advantages and disadvantages offered by the proposed converter. A study of the semiconductor losses in the indirect three-level sparse matrix converter is also included. Finally, the operation of the proposed converter is experimentally validated using a laboratory prototype.
Encapsulation of Living Bifidobacteria in Ultrathin PVOH Electrospun Fibers (2009)

This study shows the application of the electrospinning technique as a viable method for the encapsulation and stabilization of bifidobacterial strains. Poly(vinyl alcohol) (PVOH) was used as the encapsulating material because it is generally recognized as safe (GRAS), has a high oxygen barrier when dry, and is water soluble, hence allowing easy recovery of the bacteria for viability testing. A coaxial setup was used for encapsulation, and the so-obtained electrospun fibers had a mean diameter of ca. 150 nm. Incorporation of B. animalis Bb12 led to a decrease in melting point and crystallinity of the PVOH fibers and to an increase in the polymer glass transition temperature. The viability tests, carried out at three different temperatures (room temperature and 4 and -20 degrees C) showed that B. animalis Bb12 encapsulated within the electrospun PVOH fibers remained viable for 40 days at room temperature and for 130 days at refrigeration temperature, whereas a significant viability decrease was observed in both cases when bacteria were not encapsulated (p = 0.015 and p = 0.002, respectively).
Broadband spectroscopy of dynamic impedances with short chirp pulses (2011)

An impedance spectrum of dynamic systems is time dependent. Fast impedance changes take place, for example, in high throughput microfluidic devices and in operating cardiovascular systems. Measurements must be as short as possible to avoid significant impedance changes during the spectrum analysis, and as long as possible for enlarging the excitation energy and obtaining a better signal-to-noise ratio (SNR). The authors propose to use specific short chirp pulses for excitation. Thanks to the specific properties of the chirp function, it is possible to meet the needs for a spectrum bandwidth, measurement time and SNR so that the most accurate impedance spectrogram can be obtained. The chirp wave excitation can include thousands of cycles when the impedance changes slowly, but in the case of very high speed changes it can be shorter than a single cycle, preserving the same excitation bandwidth. For example, a 100 kHz bandwidth can be covered by the chirp pulse with durations from 10 µs to 1 s; only its excitation energy differs also 10(5) times. After discussing theoretical short chirp properties in detail, the authors show how to generate short chirps in the microsecond range with a bandwidth up to a few MHz by using digital synthesis architectures developed inside a low-cost standard field programmable gate array.
A catalogue quality audit tool (2002)

The current need for performance measurement and quality targets for services to users requires suitable performance indicators for libraries to use. This paper looks at the self‐assessment audit tool for catalogue quality developed by UKOLN in collaboration with Essex libraries. For the tool a checklist of errors was drawn up, which can then be used to assess the quality of records within a catalogue using a sample of library stock. The tool can be used to assess the quality of catalogue records for monographs and non‐book materials (but not serials), for complete collections or parts of collections and for records created at different periods. This paper describes the tool and the process of making the assessment and reports on the results of the pilot study carried out at the University of Bath library in 2000.