gebhart/patrepeval huggingface dataset:
Structure and order in partially oriented solids by three-dimensional magic angle spinning nuclear magnetic resonance spectroscopy (1993)

A new rotor-synchronized carbon-13 three-dimensional magic angle spinning NMR experiment for the extraction of orientational distribution functions from partially ordered solid materials is presented. Problems with overlap of two-dimensional spinning sideband patterns inherent in earlier methods are overcome by extension to three dimensions, allowing the degree of order for each resolvable carbon site to be measured. The new technique is demonstrated on a frozen smectic liquid-crystalline side group polymer which shows an order gradient from the aligned mesogen to the disordered polymer main chain.
Impact of Various Parameters Over the Adsorption of Polyvinylpyrrolidone onto Kaolin (2012)

The adsorption of water-soluble polymer, polyvinylpyrrolidone having molecular mass 9.1 ± 1.43 × 103Kg mole−1 on kaolin has been investigated. The effect of different parameters like pH, molecular mass of polymer and pre-heat treatment on the adsorption of PVP has been deliberated. The 20.7% decrease in adsorption in pH ranging from 2–10 have been found, which was an indication of the fact that with the increase in pH the kaolin surfaces sites charge amount and ultimately sign changes. Maximum adsorption was observed at pH 5.6 that was also molecular mass dependent. By increasing the pretreatment temperature, the amount of polymer adsorbed was also increased. However, above the specific temperature adsorption of PVP was decreased and attributed to decrease in specific surface area of kaolin.
Imaging hair cells through laser-ablated cochlear bone (2019)

We report an innovative technique for the visualization of cells through an overlying scattering medium by combining femtosecond laser bone ablation and two-photon excitation fluorescence (TPEF) microscopy. We demonstrate the technique by imaging hair cells in an intact mouse cochlea <i>ex vivo</i>. Intracochlear imaging is important for the assessment of hearing disorders. However, the small size of the cochlea and its encasement in the densest bone in the body present challenging obstacles, preventing the visualization of the intracochlear microanatomy using standard clinical imaging modalities. The controlled laser ablation reduces the optical scattering of the cochlear bone while the TPEF allows visualization of individual cells behind the bone. We implemented optical coherence tomography (OCT) simultaneously with the laser ablation to enhance the precision of the ablation and prevent inadvertent damage to the cells behind the bone.
A unique mode of keratinocyte death requires intracellular acidification (2021)

The stratum corneum (SC), the outermost epidermal layer, consists of nonviable anuclear keratinocytes, called corneocytes, which function as a protective barrier. The exact modes of cell death executed by keratinocytes of the upper stratum granulosum (SG1 cells) remain largely unknown. Here, using intravital imaging combined with intracellular Ca<sup>2+</sup>- and pH-responsive fluorescent probes, we aimed to dissect the SG1 death process in vivo. We found that SG1 cell death was preceded by prolonged (∼60 min) Ca<sup>2+</sup> elevation and rapid induction of intracellular acidification. Once such intracellular ionic changes were initiated, they became sustained, irreversibly committing the SG1 cells to corneocyte conversion. Time-lapse imaging of isolated murine SG1 cells revealed that intracellular acidification was essential for the degradation of keratohyalin granules and nuclear DNA, phenomena specific to SC corneocyte formation. Furthermore, intravital imaging showed that the number of SG1 cells exhibiting Ca<sup>2+</sup> elevation and the timing of intracellular acidification were both tightly regulated by the transient receptor potential cation channel V3. The functional activity of this protein was confirmed in isolated SG1 cells using whole-cell patch-clamp analysis. These findings provide a theoretical framework for improved understanding of the unique molecular mechanisms underlying keratinocyte-specific death mode, namely corneoptosis.
Quantifying how step-wise fluorination tunes local solute hydrophobicity, hydration shell thermodynamics and the quantum mechanical contributions of solute–water interactions (2020)

The ability to locally tune solute-water interactions and thus control the hydrophilic/hydrophobic character of a solute is key to control molecular self-assembly and to develop new drugs and biocatalysts; it has been a holy grail in synthetic chemistry and biology. To date, the connection between (i) the hydrophobicity of a functional group; (ii) the local structure and thermodynamics of its hydration shell; and (iii) the relative influence of van der Waals (dispersion) and electrostatic interactions on hydration remains unclear. We investigate this connection using spectroscopic, classical simulation and ab initio methods by following the transition from hydrophile to hydrophobe induced by the step-wise fluorination of methyl groups. Along the transition, we find that water-solute hydrogen bonds are progressively transformed into dangling hydroxy groups. Each structure has a distinct thermodynamic, spectroscopic and quantum-mechanical signature connected to the associated local solute hydrophobicity and correlating with the relative contribution of electrostatics and dispersion to the solute-water interactions.
The Sequence of Change within the Photosynthetic Apparatus of Wheat following Short-Term Exposure to Ozone (1991)

The basis of inhibition of photosynthesis by single acute O(3) exposures was investigated in vivo using analyses based on leaf gas exchange measurements. The fully expanded second leaves of wheat plants (Triticum aestivum L. cv Avalon) were fumigated with either 200 or 400 nanomoles per mole O(3) for between 4 and 16 hours. This reduced significantly the light-saturated rate of CO(2) uptake and was accompanied by a parallel decrease in stomatal conductance. However, the stomatal limitation, estimated from the relationship between CO(2) uptake and the internal CO(2) concentration, only increased significantly during the first 8 hours of exposure to 400 nanomoles per mole O(3); no significant increase occurred for any of the other treatments. Analysis of the response of CO(2) uptake to the internal CO(2) concentration implied that the predominant factor responsible for the reduction in light-saturated CO(2) uptake was a decrease in the efficiency of carboxylation. This was 58 and 21% of the control value after 16 hours at 200 and 400 nanomoles per mole O(3), respectively. At saturating concentrations of CO(2), photosynthesis was inhibited by no more than 22% after 16 hours, indicating that the capacity for regeneration of ribulose bisphosphate was less susceptible to O(3). Ozone fumigations also had a less pronounced effect on light-limited photosynthesis. The maximum quantum yield of CO(2) uptake and the quantum yield of oxygen evolution showed no significant decline after 16 hours with 200 nanomoles per mole O(3), requiring 8 hours at 400 nanomoles per mole O(3) before a significant reduction occurred. The photochemical efficiency of photosystem II estimated from the ratio of variable to maximum chlorophyll fluorescence and the atrazine-binding capacity of isolated thylakoids demonstrated that photochemical reactions were not responsible for the initial inhibition of CO(2) uptake. The results suggest that the apparent carboxylation efficiency appears to be the initial cause of decline in photosynthesis in vivo following acute O(3) fumigation.
Detection and surveillance of colorectal cancer (1989)

Colorectal cancer is the second most common cause of cancer in the United States. The overall mortality rate approaches 60%. However, the detection of early lesions results in a mortality rate of 20% or less. Therefore, if improvement in survival is to occur, increased efforts need to be focused not only on primary prevention but also on early detection of malignant lesions and the eradication of potentially malignant lesions. There is no universal consensus as to how this can be accomplished. The purpose of this article is to serve as a guideline, providing a practical basis for improving early detection and management of colorectal cancer and its precursors. (<i>JAMA</i>1989;261:580-585)
Single-channel user-capacity calculations for self-organizing cellular systems (1994)

One important quantity in assessing the viability of local, autonomous, dynamic channel allocation for microcellular systems is user capacity, defined as the average number of users per channel per cell. Here, we determine the capacity for infinite linear and planar arrays of microcells using a very idealized environment. In particular, propagation and interference considerations are simply represented by the constraint that, if a channel is used in a given cell, it cannot be used in R-consecutive rings of cells around that cell. We investigate the elementary case where there is only a single channel available for use in the system. Using this representation, we compute the best and worst user capacities as well as the capacity achieved by random channel placement. While the environment under which these capacities are derived is highly idealized, the results are useful in two important ways. First, the best capacity and the random channel placement capacity we find here for single-channel, self-organized access are fundamental for computing the traffic characteristics of important multichannel dynamic channel allocation algorithms. Second, the random channel placement capacity is close enough to the best that can be achieved to suggest that local, autonomously implemented, dynamic channel allocation loses little capacity when compared with centrally administered fixed channel allocation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>
Transgenerational epigenetic actions of environmental compounds. (2010)

Endocrine disrupting chemicals are known for their capacity to alter development and reproduction in mammals. One of the periods most sensitive to endocrine disruptor exposure is embryonic gonadal sex determination, when the germ line is undergoing epigenetic programming and DNA re-methylation. Epigenetic changes derived from exposure to endocrine disruptors have been described in several tissues and organisms. Endocrine disruptor induced epigenetic changes may have a wide range of phenotypic consequences, leading to disease conditions such as cancers, reproductive defects and obesity. Interestingly, the incidence of some diseases resulting from exposure to endocrine disruptors can be transgenerationally transmitted. In particular, exposure to the endocrine disruptor vinclozolin during early development is capable of inducing adult onset disease states that can be perpetuated across multiple generations. Environmental compounds such as endocrine disruptors can produce changes in the genome without altering DNA sequence. These changes are epigenetic in basis and can produce phenotypes that perpetuate transgenerationally. The suggestion that environmental factors can reprogram early development to induce epigenetic transgenerational phenotypes is a new paradigm in biology that will open new avenues for studies in disease etiology, reproduction and evolutionary biology.
Superovulation and early embryo development in the adult mouse after prenatal exposure to diethylstilboestrol (1989)

Pregnant mice were injected subcutaneously with diethylstilboestrol (DES: 10 micrograms/kg body weight in 0.1 ml corn oil) or corn oil alone on Day 15 or 16 of gestation (Day 1 = day of copulatory plug) and allowed to give birth. Female progeny from control and DES-exposed animals were superovulated with exogenous gonadotrophins at 6-8 weeks of age. In-vivo results indicated that the total number of ovulated ova, 2-cell embryos and blastocysts were significantly increased in DES-exposed progeny but that there was a decline in developmental potential from the ovulated ova stage to the blastocyst stage in these animals. However, there was no significant difference in the in-vitro development of 2-cell embryos to the blastocyst stage between control and DES-exposed animals. These results indicate that the ovaries of mice exposed in utero to DES are capable of responding to exogenous gonadotrophins and that second generation progeny have the potential for normal development to the early postblastocyst stage of embryogenesis. The in-vivo decline in developmental potential may be attributable to reproductive tract abnormalities rather than ova/embryo defects.
Nitric Oxide and the Mechanism of Rat Vascular Smooth Muscle Photorelaxation (2003)

Photorelaxation of vascular smooth muscle (VSM) was studied using segments of tail artery from normotensive rats (NTR) or spontaneously hypertensive rats (SHR). Isolated vessels with intact endothelium were perfused with Krebs solution containing phenylephrine. Perfusion pressures were recorded while arteries were irradiated with either visible (VIS; lambda=514.5 nm) or long wavelength ultra-violet (UVA; lambda=366 nm) light. VIS light produced a transient vasodilator response: a rapid decrease of pressure that recovered fully during the period (6 min) of illumination. An irradiated artery was refractory to a second period of illumination delivered immediately after the first, but its photosensitivity recovered slowly in the dark, a process called 'repriming'. Photorelaxations generated by UVA light were qualitatively different and consisted of two components: a phasic (or p-) component superimposed on a sustained (or s-) component. The p-component is similar to the VIS light-induced response in that both exhibit refractoriness and repriming depends upon endothelium-derived NO. In contrast, the s-component persists throughout the period of illumination and does not show refractoriness. We conclude that VIS light-induced photorelaxations and the p-component of UVA light-induced responses are mediated by the photochemical release of NO from a finite molecular 'store' that can be reconstituted afterwards in the dark. The s-component of the UVA light-induced response does not depend directly on endothelial NO and may result instead from a stimulatory effect of UVA light on soluble guanylate cyclase. NO-dependent photorelaxation is impaired in vessels from SHR while the s-component is enhanced.
Chiral overcrowded alkenes; Asymmetric synthesis of (3S,3?S)-(M,M)-(E)-(+)-1,1?,2,2?,3,3?,4,4?-octahydro-3,3?,7,7?-tetramethyl-4,4?-biphenanthrylidenes (2000)

An asymmetric synthesis route towards (3S,3'S)-(M,M)-(E)-(+)-1,1',2, 2',3,3',4,4'-octahydro-3,3',7,7'-tetramethyl-4,4'-biphenanthrylidene was developed using the Evans procedure as a key step. The absolute configurations of the title compound and of its parent ketone were determined by CD spectroscopy and could be correlated with the stereochemical results of the asymmetric alkylation. Furthermore, a comparison was made with the known (3R,3'R)-(P,P)-(E)-(-)-1,1',2,2', 3,3',4,4'-octahydro-3,3',7,7'-dimethyl-4,4'-biphenanthrylidene. Finally, the X-ray crystallographic analysis of (3S,3'S)-(M, M)-(E)-(+)-1,1',2,2',3,3',4,4'-octahydro-3,3',7,7'-tetramethyl-4, 4'-biphenanthrylidene is presented.
Transgenerational latent early-life associated regulation unites environment and genetics across generations (2016)

The origin of idiopathic diseases is still poorly understood. The latent early-life associated regulation (LEARn) model unites environmental exposures and gene expression while providing a mechanistic underpinning for later-occurring disorders. We propose that this process can occur across generations via transgenerational LEARn (tLEARn). In tLEARn, each person is a 'unit' accumulating preclinical or subclinical 'hits' as in the original LEARn model. These changes can then be epigenomically passed along to offspring. Transgenerational accumulation of 'hits' determines a sporadic disease state. Few significant transgenerational hits would accompany conception or gestation of most people, but these may suffice to 'prime' someone to respond to later-life hits. Hits need not produce symptoms or microphenotypes to have a transgenerational effect. Testing tLEARn requires longitudinal approaches. A recently proposed longitudinal epigenome/envirome-wide association study would unite genetic sequence, epigenomic markers, environmental exposures, patient personal history taken at multiple time points and family history.
Design of dual‐mode pentagon patch resonator filter using asymmetrical λ/4 interdigital coupled lines (2009)

Abstract In this letter, an improved coupling mechanism using asymmetrical λ/4 interdigital coupled lines is introduced and applied to design dual‐mode pentagon patch resonator filter. This perturbation method is easy to realize without occupying extra space while the patch resonator structure remains intact. Coupling characteristics and transmission characteristics of this new filter are discussed, and the design methodology is verified by measurements. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51:2817–2819, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24783
LIDAR Measurements Of The Troposphere And Middle Atmosphere (1989)

Tropospheric and middle atmosphere measurements using lidar systems at the University of Maryland are described. Measurements include depolarization by clear atmosphere and high altitude cirrus clouds, cloud morphology for cirrus and tropospheric haze and clouds, and rapid variations of the cloud free line-of-sight. Rayleigh scattering from the stratosphere and mesosphere is employed to derive temperature and density profiles. A photon counting system has been developed for extending temperature measurements into the mesosphere. We are also constructing a transportable lidar system for clear air, aerosol, cirrus cloud, mesospheric cloud, and sodium measurements at geographical locations of interest for atmospheric propagation studies. The lidar measurements will bear directly on selection of sites for tests and operation of ground based high energy lasers, and on estimation of extinction in long range optical detection and tracking of targets.
DNA Hybridization: Direct Attachment of Microbial Organisms to Material Surfaces Through Sequence‐Specific DNA Hybridization (Adv. Mater. 18/2012) (2012)

M. B. Francis and co-workers develop a new chemical method for the attachment of single-stranded DNA molecules to the surfaces of these organisms. On page 2380, they describe how, when exposed to substrates bearing the sequence complements, the microbes can be attached to specified locations with very high efficiency. The use of multiple DNA sequences allows complex microbial ‘communities’ to be generated, potentially allowing the study of symbiotic relationships. Shown are Synechocystis (red), Saccharomyces cerevisiae (green), and Azotobacter vinelandii (blue).
Detection and Identification of Coxiella burnetii Based on the Mass Spectrometric Analyses of the Extracted Proteins (2008)

Rapid and reliable detection, identification, and typing of bacterial species are necessary in response to natural or terrorist-caused outbreaks of infectious diseases and play crucial roles in diagnosis and efficient treatment. We report here two proteomic approaches with a high potential in the detection and identification of Coxiella burnetii, the causative agent of Q fever. The first of them starts with the acetonitrile (ACN) and trichloroacetic acid extractions of inactivated C. burnetii cells followed by the detection of extracted molecules and ions derived from the inactivated cells by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. In the second approach, identification of the proteins extracted by ACN is accomplished after enzymatic digestion by electrospray tandem mass spectrometry coupled to a nanoscale ultraperformance liquid chromatography (LC-MS/MS). In order to observe morphological differences on the surface structures upon extraction, the inactivated and treated cells of the bacterium were examined by electron microscopy. The LC-MS/MS approach has allowed identification of 20 proteins in the ACN extracts of C. burnetii strain RSA 493 that were observed in more than 3 out of 10 experiments.
Congenital Lipedematous Alopecia: Adding to the Differential Diagnosis of Congenital Alopecia (2015)

Lipedematous alopecia is a rare condition of unknown etiology characterized by a thick boggy scalp with varying degrees of hair loss. It is usually seen in adult African-American females, and a case in a 9-year-old was the youngest patient reported thus far. We report on the appearance of this condition in two children, a 6-year-old child and a 10-year-old child. Each presented with congenital patchy hair loss on the occipital area and the left temple. A boggy hairless scalp with soft swelling was detected in both patients. Histological examination showed increased thickness of the subcutaneous fat tissue with a decrease in hair follicles. These features were consistent with a diagnosis of lipedematous alopecia. We report two cases of congenital lipedematous alopecia, which has not been reported previously. Although congenital, these distinct clinical features should be kept in mind in the diagnosis of alopecic hair loss.
Development and Performance of a Hand-Held CZT Detector for In-Situ Measurements at the Emergency Response (2016)

Background: A hand-held detector for an emergency response was developed for nuclide identification and to estimate the information of the ambient dose rate in the scene of an accident as well as the radioactivity of the contaminants.Materials and Methods: To achieve this, the most suitable sensor was first selected as a cadmium zinc telluride (CZT) semiconductor and the signal processing unit from a sensor and the signal discrimination and storage unit were successfully manufactured on a printed circuit board.Results and Discussion: The performance of the developed signal processing unit was then evaluated to have an energy resolution of about 14 keV at 662 keV.The system control unit was also designed to operate the CZT detector, monitor the detector, battery, and interface status, and check and transmit the measured results of the ambient dose rate and radioactivity.In addition, a collimator, which can control the inner radius, and the airborne dust sampler, which consists of an air filter and charcoal filter, were developed and mounted to the developed CZT detector for the quick and efficient response of a nuclear accident. Conclusion:The hand-held CZT detector was developed to make the in-situ gamma-ray spectrometry and its performance was checked to have a good energy resolution.In addition, the collimator and the airborne dust sampler were developed and mounted to the developed CZT detector for a quick and efficient response to a nuclear accident.
Large signal design of broadband monolithic microwave frequency dividers (2003)

A monolithic regenerative divider by two with a 6-GHz central input frequency has been designed and fully characterized using an improved harmonic balance formulation, suitable to deal with autonomous and phase-locked regimes. The solution paths when the input generator power and frequency are modified have been traced. The output power at the divided frequency has been evaluated as a function of both parameters as well as the output power of the free running oscillator regime. Results have been experimentally verified, and excellent agreement has been obtained. Frequency jumps and hysteresis phenomena often encountered in such devices can be fully analyzed, thus providing a useful tool for a thorough investigation of synchronized devices.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>