gebhart/patrepeval huggingface dataset:
Initial Characterization of Dark-Field CT on a Clinical Gantry (2022)

&lt;p&gt;X-ray computed tomography (CT) is an important non-destructive imaging technique, particularly in clinical diagnostics. Even with the latest innovations like dual-energy and photon-counting CT, the image contrast is solely generated from attenuation in the tissue. An extension -- fully compatible with these novelties -- is dark-field CT, which retrieves an additional, so-called dark-field contrast. Unlike the attenuation channel, the dark-field channel is sensitive to tissue microstructure and porosity below the resolution of the imaging system, which allows additional insights into the health of the lung tissue or the structure of calcifications. The potential clinical value has been demonstrated in several preclinical studies and recently also in radiography patient studies. Just recently the first dark-field CT for the human body was established at the Technical University of Munich and in this paper, we discuss the performance of this prototype. We evaluate the interferometer components and the imposed challenges that the integration into the CT gantry brings by comparing the results to simulations and measurements at a laboratory setup. The influence of the clinical X-ray source on the Talbot-Lau interferometer and the impact of vibrations, which are immanent on the clinical CT gantry, are analyzed in detail to reveal their characteristic frequencies and origin. A beam hardening correction is introduced as an important step to adapt to the poly-chromatic spectrum and make quantitative dark-field imaging possible. We close with an analysis of the image resolution and the applied patient dose, and conclude that the performance is sufficient to suggest initial patient studies using the presented dark-field CT system.&lt;/p&gt;
Suppression of the Floating-Body Effect in Poly-Si Thin-Film Transistors With Self-Aligned Schottky Barrier Source and Ohmic Body Contact Structure (2004)

In this letter, we developed a new self-aligned Schottky barrier source and ohmic body contact (SSOB) method that can effectively suppress the floating-body effect in poly-Si thin-film transistors (TFTs). Experimental results show that the SSOB-TFTs give higher output resistance, less threshold voltage variation, improved subthreshold characteristics, and larger breakdown voltage compared with conventional TFTs. The characteristics of the SSOB-TFTs are suitable for high-performance driving TFTs with a high output resistance and large breakdown voltage.
Influence of Charge Fraction on the Phase Behavior of Symmetric Single-Ion Conducting Diblock Copolymers (2021)

A series of symmetric poly[(oligo(ethylene glycol) methyl ether methacrylate-<i>co</i>-oligo(ethylene glycol) propyl sodium sulfonate methacrylate)]-<i>block</i>-polystyrene (P<i>s</i>OEGMA-PS) diblock copolymers were synthesized as a model system to probe the effect of charge fraction on the phase behavior of charged-neutral single-ion conducting diblock copolymers. Small-angle X-ray scattering (SAXS) experiments showed that increasing the charge fraction does not alter the ordered phase morphology (lamellar) but increases the order-disorder transition temperature (<i>T</i><sub>ODT</sub>) significantly. Additionally, the effective Flory-Huggins interaction parameter (χ<sub>eff</sub>) was found to increase linearly with the charge fraction, similar to the case of conventional salt-doped diblock copolymers. This indicates that the effect of counterion solvation, attributed to the significant mismatch between the dielectric constant of each block, provides the dominant effect in tuning the phase behavior of this charged diblock copolymer. We therefore infer that electrostatic cohesion (local charge ordering induced by Coulombic interactions), which is predicted to suppress microphase separation and lead to asymmetric phase diagrams, only plays a minor role in this model system.
Optimization of Biomass Pyrolysis Vapor Upgrading Using a Laminar Entrained-Flow Reactor System (2020)

A custom bench-scale continuous-flow catalytic fast-pyrolysis (CFP) reactor system was implemented for the optimization of ex situ CFP and screening of catalysts to gain insight into commercial scale ex situ CFP processes across various reactor types. Operated in an ex situ configuration, tandem laminar entrained-flow pyrolyzer and vapor-phase upgrading reactors were optimized to successfully demonstrate CFP of pine over two different commercial zeolite catalysts. Mixing-enhancers within the vapor-phase upgrader induced laminar flow dynamics with larger Reynold’s numbers, thus enhancing heat and mass transfer and in turn CFP conversion. Real-time analysis of products was accomplished via molecular beam mass spectrometry (MBMS), while light gas yield was determined using nondispersive infrared (NDIR) analysis. The transfer of the pyrolysis vapors to the vapor-phase upgrader was investigated to gain insight into optimal transfer-line conditions for limiting secondary thermal cracking and preserving carbon in the ex situ CFP process. The products were comparable to those previously obtained from fixed bed and fluidized bed reactor systems as well as entrained-flow riser reactor systems (e.g., one-ring aromatics, polyaromatics, and phenolics). Replicate experiments demonstrated a good average mass balance closure: 14 wt % oil, 27 wt % aqueous, 26 wt % char, 12 wt % total coke (system and catalyst coke), and 21 wt % light gas (CO, CO2, and CH4) with overall closure of ∼100%. Similar trends in catalyst deactivation were observed for the laminar entrained-flow reactor system with decreasing catalyst-to-biomass ratio as reported in the literature. Under optimized continuous-flow conditions, constant catalyst activity was maintained, suggesting that the laminar entrained-flow reactor system was a viable option for the CFP of pine. Minor differences in catalytic activity were observed for the two catalysts tested.
ChemInform Abstract: Addition of a Silyl Ketene Acetal to α,β‐Unsaturated Cyclic Anhydrides. (2010)

Abstract Addition of silyl ketene acetal (II) to itaconic anhydride (I) in the presence of a Lewis acid, Yb(OFf) 3 , proceeds in a 1,4‐fashion.
Bifunctional intercalation of antitumor antibiotics BBM-928A and echinomycin with DNA. Effects of intercalation on DNA degradative activity of bleomycin and phleomycin (1982)

The binding of peptide antitumor antibiotics, BBM-928A and echinomycin, to superhelical PM2 DNA and the effects of the resulting conformational changes of DNA on the DNA-degradative activity of two related antitumor antibiotics, bleomycin A2 and phleomycin D1, have been studied. The bifunctional intercalative mode of the DNA binding of BBM-928A concluded previously from viscometric and fluorometric studies has been confirmed by gel electrophoretic analysis. Under the employed electrophoretic conditions, DNA-bound BBM-928A showed little dissociation whereas echinomycin and ethidium bromide showed partial and nearly complete dissociation, respectively. BBM-928A induced neither single-strand nor double-strand breaks in DNA. Competitive binding studies by fluorescence changes suggested that binding sites on DNA molecules for BBM-928A (or echinomycin) may differ from those for ethidium bromide, since binding to DNA by the two drugs was not competitive even at saturating concentrations. The lack of such a competition between the two drugs is not consistent with the neighbor-exclusion principle. The DNA-degradative activity of both bleomycin A2 and phleomycin D1 increased with the removal of the negative superhelicity of DNA by the BBM-928A intercalation and decreased with the formation of positive superhelical turns induced by high concentrations of BBM-928A. Thus the degradative activity of both bleomycin A2 and phleomycin D1 is sensitive in a similar manner to the degree of superhelicity rather than the double helicity of DNA, although there are differences between these two drugs in interaction with DNA.
Energetic, Topological and Electric Field Analyses of Cation‐Cation Nucleic Acid Interactions in Watson‐Crick Disposition (2018)

A theoretical study of the effect of the diprotonation on the nucleic acid bases (A : U, A : T and G : C) in Watson-Crick conformation has been carried out by means of DFT computational methods in vacuum. In addition, the corresponding neutral and monoprotonated binary complexes have been considered. Most of the diprotonated species studied are stable, even though the binding energy is positive due to the overall repulsive electrostatic term. Local electrostatic attractive forces in the regions of hydrogen bonds (HBs) are responsible for equilibrium geometries, as shown by the electric field lines connecting the electrophilic and nucleophilic sites involved in the HB interactions. Secondary electrostatic effects also affect the assembling of the nucleic acid complexes in either neutral or cationic form. In particular, the electric field lines flowing from electrophilic sites in one base to nucleophilic sites in the other reinforce the linking between them. Hence, when the nucleophilic site concerns the free lone pair of the heteroatom involved in the HB interaction as acceptor, the HB distance shortens. However, if the free lone pair of the HB acceptor interacts with an electrophilic site in the same molecule, the HB distance elongates, weakening the HB interaction. The topological analysis of the electron density distribution in HB regions indicates that neutral, monoprotonated and diprotonated complexes show no differences in the nature of their HB's.
Breast carcinoma cells promote the differentiation of CD34+ progenitors towards 2 different subpopulations of dendritic cells with CD1ahighCD86−Langerin‐ and CD1a+CD86+Langerin+ phenotypes (2004)

Primary breast carcinoma are frequently infiltrated by dendritic cells (DC). The mechanisms involved in the localization and status of activation of DC within primary breast carcinoma were investigated. CCL20/MIP3alpha, a chemokine involved in immature DC and their precursors attraction, was detected by immunohistochemistry on cryopreserved tissue sections of primary breast tumors and by ELISA and biological assay in metastatic effusion fluids from breast cancer patients but not from other tumors. In vitro, irradiated breast carcinoma cell lines (BCC) as well as their conditioned media promoted CD34+ cell differentiation into CD1a+ Langerhans cells (LC) precursors as early as day 6, while at day 12, 2 different CCR6+ subpopulations of DC with a Langerhans cell (CD1a(+)Langerin(+)CD86+) and an immature DC (CD1a(high)Langerin-CD86(-)HLA-DR(low)CD40(low)) phenotype were observed. This phenomenon was partly driven by a TGFbeta-dependent mechanism since a pan TGFbeta polyclonal antibody completely blocks BCC-induced LC differentiation and partly reduces immature DC development. These DC failed to maturate in response to sCD40L or LPS stimuli and CD1a(high)Langerin(-)CD86- cells have a reduced T-cell stimulatory capacity in MLR experiments. The absolute number of T cells was reduced by 50% in both the CD4+ or CD8+ compartments, these T cells expressing lower levels of the CD25 Ag and producing less IFNgamma. These results show that breast carcinoma cells produce soluble factors, which may attract DC and their precursors in vivo, and promote the differentiation of the latter into LC and immature DC with altered functional capacities. The infiltration of BCC by these altered DC may contribute to the impaired immune response against the tumor.
Ghrelin-Induced Orexigenic Effect in Rats Depends on the Metabolic Status and Is Counteracted by Peripheral CB1 Receptor Antagonism (2013)

Ghrelin is an endogenous regulator of energy homeostasis synthesized by the stomach to stimulate appetite and positive energy balance. Similarly, the endocannabinoid system is part of our internal machinery controlling food intake and energy expenditure. Both peripheral and central mechanisms regulate CB1-mediated control of food intake and a functional relationship between hypothalamic ghrelin and cannabinoid CB1 receptor has been proposed. First of all, we investigated brain ghrelin actions on food intake in rats with different metabolic status (negative or equilibrate energy balance). Secondly, we tested a sub-anxiogenic ultra-low dose of the CB1 antagonist SR141716A (Rimonabant) and the peripheral-acting CB1 antagonist LH-21 on ghrelin orexigenic actions. We found that: 1) central administration of ghrelin promotes food intake in free feeding animals but not in 24 h food-deprived or chronically food-restricted animals; 2) an ultra-low dose of SR141716A (a subthreshold dose 75 folds lower than the EC50 for induction of anxiety) completely counteracts the orexigenic actions of central ghrelin in free feeding animals; 3) the peripheral-restricted CB1 antagonist LH-21 blocks ghrelin-induced hyperphagia in free feeding animals. Our study highlights the importance of the animaĺs metabolic status for the effectiveness of ghrelin in promoting feeding, and suggests that the peripheral endocannabinoid system may interact with ghrelińs signal in the control of food intake under equilibrate energy balance conditions.
Infrared matrix study of reactions of UF4 with fluorine (1976)

Chemical reactions between UF4 and fluorine to produce UF5 and UF6 were studied by the technique of matrix isolation and observation of infrared spectra of reacting species in the matrix.(AIP)
Determinants of Perivascular Spaces in the General Population (2022)

Various factors are associated with the burden of PVS, in part regionally specific, which points toward a multifactorial origin beyond what can be expected from PVS-related risk factor profiles. This study highlights the power of collaborative efforts in population neuroimaging research.
Linearity In BSDF Measurements (1990)

A method to generate a transfer function accounting for instrument measurement non-linearities is given. The BSDF instrument itself is used to make two measurement scans. One of these scans is taken at normal incident power and the second with a neutral density filter in the optics chain. Using the information generated by these scans, and assuming that the system is linear over some range of its operation, a transfer function may be generated to characterize the system and to allow non-linearities to be compensated for.
Nanotechnology in Drug Delivery and Tissue Engineering: From Discovery to Applications (2010)

The application of nanotechnology in medicine, referred to as nanomedicine, is offering numerous exciting possibilities in healthcare. Herein, we discuss two important aspects of nanomedicine, drug delivery and tissue engineering, highlighting the advances we have recently experienced, the challenges we are currently facing, and what we are likely to witness in the near future.
Pharmacokinetics of the TRPV1 Antagonist ABT‐102 in Healthy Human Volunteers: Population Analysis of Data From 3 Phase 1 Trials (2011)

ABT-102 is a selective TRPV1 antagonist with robust efficacy in several preclinical models of pain. Three phase 1 studies evaluated ABT-102 pharmacokinetics upon oral administration to healthy human volunteers: a single-dose study (2, 6, 18, 30, and 40 mg) and a multiple-dose study (2, 4, and 8 mg twice daily for 7 days) using a solution formulation and a multiple-dose study (1, 2, and 4 mg twice daily for 7 days) using a solid-dispersion formulation. These studies followed double-blind, randomized, placebo-controlled designs. ABT-102 exhibited dose- and time-linear pharmacokinetics. ABT-102 half-life ranged from 7 to 11 hours, and steady state was achieved by day 5 of dosing. Population analysis of the pharmacokinetic data from the 3 studies was conducted. A 1-compartment model with a transit compartment for absorption and first-order elimination provided best fit to the data. The model included formulation-dependent lag times and a bioavailability factor (F(rel)) for solution relative to solid dispersion. The population parameter estimates (95% bootstrap confidence intervals) were oral clearance, 16 (14-18) L/h; oral volume of distribution, 215 (192-237) L; transit rate constant, 1.4 (1.3-1.6) h(-1); solid-dispersion lag, 0.6 (0.5-0.8) h; solution lag, 0.3 (0.2-0.4) h; and solution F(rel), 40% (35%-45%). Evaluation of ABT-102 pharmacokinetic model indicated its robustness and adequacy.
Three Dimensional Structure-Electrical Properties of Oriented PPV and PANI Films (2003)

In this paper the influence of anisotropic molecular structure on the three dimensional electrical properties of both poly(phenylene vinylene), (PPV), and polyaniline, (PANI) oriented films is investigated. The anisotropic structure of the stretched PPV and PANI EB films were examined using a modified waveguide coupler while three dimensional impedance spectroscopy measurements were made using specially designed test fixtures that allowed the in-plane as well as the through-plane impedance to be measured. The unstretched PANI EB film has a random orientation and one-way stretching leads to a uniaxial structure. The unstretched PPV film, on the other hand, was found to have a highly planar structure and oneway stretching converts the planar structure to a uniaxial structure. Impedance measurements were made on PANI after it was doped with HCl while PPV films were measured in the undoped state. For HCl-doped PANI films, the conductivity along the stretch direction was found to increase with orientation. For undoped PPV films, the conductivity through the film thickness direction decreased with increasing orientation. For both polymers, the in-plane conductivity was significantly greater than the through-plane conductivity.
Analysis of n-channel MOS-controlled thyristors (1991)

The turn-off of the n-channel MOS-controlled thyristor (NMCT) is analyzed using two-dimensional simulation. A lateral NMOS-controlled thyristor structure, LNMCT, suitable for HVIC application is also proposed. It is found that the operation of a parasitic lateral n-p-n transistor in NMCT-type structures degrades the forward voltage drop and the turn-off capability and hence should be suppressed. The maximum controllable current in the NMCT is not only a function of internal parameters, but also depends on external supply voltage. This indicates that snubberless operation of an MCT-type device is not feasible. The advantages and disadvantages of the NMCT are compared with those of conventional MCT structures. The LNMCT turn-off speed is limited by the large amount of holes existing in the substrate, resulting in a turn-off waveform similar to that of an LIGBT.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>
A Data-Driven Sequential Backward Selection Framework to Accelerate Diffusion-Relaxation Prostate Microstructure Mapping (2023)

Diffusion-Relaxation Correlation Spectrum Imaging (DR-CSI) can provide unique microstructural information for prostate cancer characterization, but requires longer scan times for two-dimensional encoding of TE and b-values. This study developed a data-driven sequential backward selection framework that determined subsampled encoding schemes for DR-CSI, achieving 70% reduction of scan time to 6min while maintaining accurate ex vivo prostate microstructure mapping.
Insulin resistance due to a defect distal to the insulin receptor: Demonstration in a patient with leprechaunism (1978)

We have studied a 2-year-old girl with acanthosis nigricans, glucose intolerance, marked hyperinsulinemia, and somatic features characteristic of the leprechaunism syndrome. Circulating plasma insulin levels were increased up to 50-fold and the patient showed a blunted hypoglycemic response to an injection of exogenous insulin (0.2 units/kg), indicating the presence of severe insulin resistance. Insulin purified from the patient's plasma was normal on the basis of chromatographic, electrophoretic, and immunologic criteria. Furthermore, the purified insulin competed effectively with (125)I-labeled insulin for binding to insulin receptors on cultured IM-9 lymphocytes and rat fat cells and also exhibited normal biological potency when tested on rat fat cells. Anti-insulin receptor and anti-insulin antibodies were not detected in the patient's plasma, and plasma levels of glucagon, growth hormone, and cortisol were normal. Insulin binding to the patient's circulating monuclear leukocytes was only slightly depressed into the low normal range and could not account for the severe insulin resistance. Studies on the patient's fibroblasts revealed normal levels of insulin receptors but a total absence of insulin's ability to accelerate glucose transport. Because rates of glucose transport and metabolism were normal in the basal state in the absence of insulin, we conclude that this patient's insulin resistance is due to an inherited cellular defect in the coupling mechanism between occupied insulin receptors and the plasma membrane glucose transport system.
Scatterometry for in situ measurement of pattern reflow in nanoimprinted polymers (2008)

We use optical scatterometry to extract the time evolution of the profile of nanoimprinted lines in low and high molecular mass polymer gratings during reflow at the glass transition temperature. The data are obtained continuously during the anneal using a spectroscopic ellipsometer and analyzed using a rigorous-coupled-wave model. We show excellent agreement of scatterometry results with ex situ measurements of line height by atomic force microscopy and specular x-ray reflectivity. The in situ scatterometry results reveal differences in the shape evolution of the grating lines indiscernible by other methods.
3‐D near‐field imaging of guided modes in nanophotonic waveguides (2017)

Abstract Highly evanescent waveguides with a subwavelength core thickness present a promising lab‐on‐chip solution for generating nanovolume trapping sites using overlapping evanescent fields. In this work, we experimentally studied Si 3 N 4 waveguides whose sub‐wavelength cross‐sections and high aspect ratios support fundamental and higher order modes at a single excitation wavelength. Due to differing modal effective indices, these co‐propagating modes interfere and generate beating patterns with significant evanescent field intensity. Using near‐field scanning optical microscopy (NSOM), we map the structure of these beating modes in three dimensions. Our results demonstrate the potential of NSOM to optimize waveguide design for complex field trapping devices. By reducing the in‐plane width, the population of competing modes decreases, resulting in a simplified spectrum of beating modes, such that waveguides with a width of 650 nm support three modes with two observed beats. Our results demonstrate the potential of NSOM to optimize waveguide design for complex field trapping devices.
An Unexpected Synthesis of Ketene Monothioacetals. (2007)

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.