gebhart/patrepeval huggingface dataset:
Influence of Fe(II) on the Formation of the Spinel Iron Oxide in Alkaline Medium (1992)

Abstract Fe(II) and Fe(III) in various proportions were coprecipitated by NH 3 at pH ≈ 11. The Fe(II)/Fe(III) ratio (x) was varied from 0.10 to 0.50. After stabilization by aging at pH ≃ 8 in anaerobic conditions, hydrous precipitates were characterized by electron microscopy, Mössbauer spectroscopy, and kinetics of dissolution in acidic medium. At any x value, all stable products exhibited the structure of (oxidized) magnetite. For x ≤ 0.30, two distinct species were coexisting: the one (“m”) was made up of ca. 4nm-sized particles with a low Fe(II) content (Fe(II)/Fe(III) ≈ 0.07), and the other (“M”) consisted of particles of larger, more or less distributed sizes, and composition Fe(II)/Fe(III) ≈ 0.33; “M” increased relative amount with increasing x. For x ≥ 0.35, “M” was the only constituent and its Fe(II)/Fe(III) ratio was equal to x. “M” is identified with (nonstoichiometric) magnetite, whereas “m” is likely to be an oxyhydroxide. Mechanisms of formation are discussed, and a phase diagram is proposed which schematizes the evolution of the coprecipitation products with x and with time. Addition of Fe(II) after the precipitation of Fe(III), instead of coprecipitation, yielded very similar results.
Apparent reversion to trophism of a free omental graft: a preliminary report. (1962)

In a previous paper we reported evidence which suggested that a free omental graft has trophic characteristics similar to those of the chorionic epithelium of the early embryo, through which it establishes arteriolar or larger connections with aorta, heart and pericardium within 10 days after it has been placed in contact with the denuded surfaces of each structure. The theory of omental trophism was tested by dropping pieces of omentum completely detached into the pleural and peritoneal cavities of white rats. When examined 25 or more days later a percentage of omental grafts appeared healthy and were attached to pleura, lung, heart and to various structures in the peritoneal cavity. In the pleural grafts, histological sections revealed a continuity between the omental grafts and the sub-pleural tissues. A blood-hungry free omental graft appears to seek out its own blood supply. Neither pleura nor serosa was able to repel its primitive probing for a new blood supply.
Time dependent analysis of active and passive optical bistability in semiconductors (1985)

A time-dependent theory of optical bistability is developed and applied to laser amplifiers and passive semiconductor etalons. Results of the theory show an output intensity spike in switch-up which occurs after a time delay determined largely by the carrier recombination time, and before which the transition is unstable. Although for passive etalons the spike is rather broad (of order 1 ns for parameters appropriate to GaAs at 0.85 μm or InGaAsP at 1.55 μm) and of low amplitude, for amplifiers it is roughly an order of magnitude narrower and higher in amplitude. As a consequence, it is predicted that clock speeds for semiconductor bistable switching elements will be limited to rates commensurate with the carrier recombination time, not only for switch-down operations (as already well known) but also for switch-up operations.
A 2005 On the stability and structural dynamics of metal nanowires (2016)

This article presents a brief review of the nanoscale free-electron model, which provides a continuum description of metal nanostructures. It is argued that surface and quantum-size effects are the two dominant factors in the energetics of metal nanowires, and that much of the phenomenology of nanowire stability and structural dynamics can be understood based on the interplay of these two competing factors. A linear stability analysis reveals that metal nanocylinders with certain magic conductance values G=1,3,6,12,17,23,34,42,51,67,78,96,... times the conductance quantum are exceptionally stable. A nonlinear dynamical simulation of nanowire structural evolution reveals a universal equilibrium shape consisting of a magic cylinder suspended between unduloidal contacts. The lifetimes of these metastable structures are also computed.
Neocortical Neuronal Diversity: Chemical Heterogeneity Revealed by Colocalization Studies of Classic Neurotransmitters, Neuropeptides, Calcium-binding Proteins, and Cell Surface Molecules (1993)

The use of immunocytochemical and histochemical methods to study colocalization of two or more chemical compounds in the same neuron has revealed that there is a great diversity of neocortical neurons. Neurons double stained for two or more substances are found in all layers, except in layer I, in all cortical areas and species studied so far, but there seem to be differences in the proportions and numbers of neurons double stained for a particular combination of substances between different species, and between cortical layers and cortical areas of the same species. With few (though important) exceptions, the majority of classic neurotransmitters, neuropeptides, calcium-binding proteins, and cell surface molecules currently known to be present in the neocortex are localized mainly, if not exclusively, in smooth nonpyramidal cells. Therefore, chemical diversity of neurons in the neocortex is mainly a feature of the population of nonpyramidal cells. It seems clear that no combinations of double staining are found exclusively in a single morphological type of nonpyramidal neuron. However, in some species, certain combinations are found selectively in particular groups of smooth nonpyramidial neurons. Conversely, the same morphological type of neuron can display a variety of chemical characteristics depending on the species and cortical area and layer in which it is located. These studies have so far proved useful to characterize and identify cortical neuronal subpopulations and cortical circuits anatomically, but they probably have functional significance as well.
Ultrathin membranes in x-cut lithium niobate (2009)

Ion-beam enhanced etching is used to pattern a bulk lithium niobate crystal with ultrathin membranes. By the implementation of an air gap beneath the membrane, high index contrast is achieved. A buried amorphous layer, created by irradiation with He ions, is removed by means of wet chemical etching in hydro-fluoric acid. Membranes having thicknesses down to 200 nm are fabricated. The etched air gaps and the membranes exhibit a uniform thickness over the entire etched area, and their widths can be purposefully adjusted over a wide range by choosing appropriate ion energies and fluences as well as annealing conditions.
Selective Circuits and Static Interference* (1925)

The present paper has its inception in the need of a correct understanding of the behavior of selective circuits when subjected to irregular and random interference, and of devising a practically useful figure of merit for comparing circuits designed to reduce the effects of this type of interference. The problem is essentially a statistical one and the results must be expressed in terms of mean values The mathematical theory is developed from the idea of the spectrum of the interference and the response of the selective circuit is expressed in terms of the mean square current and mean power absorbed. The application of the formulas deduced to the case of static interference is discussed and it is shown that deductions of practical value are possible in spite of meagre information regarding the precise nature and origin of static interference. The outstanding deductions of practical value may be summarized as follows: 1. Even with absolutely ideal selective circuits, an irreducible minimum of interference will be absorbed, and this minimum increases linearly with the frequency range necessary for signaling. 2. The wave-filter, when properly designed, approximates quite closely to the ideal selective circuit, and little, if any, improvement over its present form may be expected as regards static interference. 3. As regards static or random interference, it is quite useless to employ extremely nigh selectivity. The gain, as compared with circuits of only moderate selectivity, is very small, and is inevitably accompanied by disadvantages such as sluggishness of response with consequent slowing down of the possible speed of signaling. 4. A formula is developed, which, together with relatively simple experimental data, provides for the accurate determination of the spectrum of static interference. 5. An application of the theory and formulas of the paper to representative circuit arrangements and schemes designed to reduce static interference, shows that they are incapable of reducing, in any substantial degree, the mean interference, as compared with what can be done with simple filters and tuned circuits. The underlying reason lies in the nature of the interference itself.
Pervasive post‐transcriptional control of genes involved in amino acid metabolism by the Hfq‐dependent GcvB small RNA (2011)

GcvB is one of the most highly conserved Hfq-associated small RNAs in Gram-negative bacteria and was previously reported to repress several ABC transporters for amino acids. To determine the full extent of GcvB-mediated regulation in Salmonella, we combined a genome-wide experimental approach with biocomputational target prediction. Comparative pulse expression of wild-type versus mutant sRNA variants revealed that GcvB governs a large post-transcriptional regulon, impacting ~1% of all Salmonella genes via its conserved G/U-rich domain R1. Complementary predictions of C/A-rich binding sites in mRNAs and gfp reporter fusion experiments increased the number of validated GcvB targets to more than 20, and doubled the number of regulated amino acid transporters. Unlike the previously described targeting via the single R1 domain, GcvB represses the glycine transporter CycA by exceptionally redundant base-pairing. This novel ability of GcvB is focused upon the one target that could feedback-regulate the glycine-responsive synthesis of GcvB. Several newly discovered mRNA targets involved in amino acid metabolism, including the global regulator Lrp, question the previous assumption that GcvB simply acts to limit unnecessary amino acid uptake. Rather, GcvB rewires primary transcriptional control circuits and seems to act as a distinct regulatory node in amino acid metabolism.
Organizing a Global Coordinate System from Local Information on an Amorphous Computer (1999)

Abstract. We demonstrate that it is possible to achieve accurate localization and tracking of a target in a randomly placed wireless sensor network composed of inexpensive components of limited accuracy. The crucial enabler for this is a reasonably accurate local coordinate system aligned with the global coordinates. We present an algorithm for creating such a coordinate system without the use of global control, globally accessible beacon signals, or accurate estimates of inter-sensor distances. The coordinate system is robust and automatically adapts to the failure or addition of sensors. Extensive theoretical analysis and simulation results are presented. Two key theoretical results are: there is a critical minimum average neighborhood size of 15 for good accuracy and there is a fundamental limit on the resolution of any coordinate system determined strictly from local communication. Our simulation results show that we can achieve position accuracy to within 20 % of the radio range even when there is variation of up to 10 % in the signal strength of the radios. The algorithm improves with finer quantizations of inter-sensor distance estimates: with 6 levels of quantization position errors better than 10 % are achieved. Finally we show how the algorithm gracefully generalizes to target tracking tasks. 1
Joint distributed synchronization and positioning in UWB ad hoc networks using TOA (2006)

In this paper, we describe a global distributed solution that enables the simultaneous performance of time synchronization and positioning in ultra-wideband (UWB) ad hoc networks. On the one hand, the proposed synchronization scheme basically relies on cooperative two-way-ranging/time-of-arrival transactions and a diffusion algorithm that ensures the convergence of clock parameters to average reference values in each node. Although the described solution is generic at first sight, its sensitivity to time-of-arrival accuracy imposes the choice of an impulse-radio ultra-wideband physical layer in the very context. On the other hand, a distributed algorithm coupled with this synchronization scheme mitigates the impact of non-line-of-sight ranging errors on positioning accuracy without any additional protocol hook. More particularly, the realistic UWB ranging error models we use take into account UWB channel effects, as well as detection noises and relative clock drifts. Then, it is demonstrated that a cooperative and distributed maximization of the log-likelihood of range estimates can reduce the uncertainty on estimated positions in comparison with classical distributed weighted least squares approaches. Finally, the proposed distributed maximum log-likelihood algorithm proves to preserve a reasonable level of complexity in each node by approximating asynchronously the positive gradient direction of the log-likelihood function. For both distributed synchronization and positioning algorithms, simulation results are provided to illustrate the relevance of such a solution.
Fusion of MRI and CT with Subdural Grid Electrodes (2004)

In patients with drug-resistant focal epilepsies subdural grid electrodes may be implanted to determine the seizure onset zone and eloquent cortex areas. Since the spatial relationship of the grid to the underlying brain is poorly visualized on MRI, we co-registered MRI before and CT after implantation of subdural grid electrodes. In this study we sought an appropriate algorithm to combine both imaging modalities. We compared six different co-registration algorithms including surface-oriented, mutual information-based and landmark-based methods. The resulting overlay matrices were analyzed by calculating rotational and translational shifts and by judging co-registered MRI and CT scans visually. A brain surface oriented method had the lowest rotational (axial 0.7 +/- 0.6 degrees; coronal 1.7 +/- 1.1 degrees; sagittal 1.9 +/- 1.8 degrees) and translational shifts (3.7 +/- 1.3 mm). It was judged visually to be the best, had a low intra- and inter-observer variability, and lasted approximately 15 minutes. This algorithm is recommended when co-registering MRI before and CT after implantation of subdural grid electrodes. Skin-, voxel-, and landmark-based algorithms are less accurate, which is most likely due to postsurgical deformation of extra- and intracranial soft tissue.
An integrated multiple silicon drift detector system for transmission electron microscopes (2010)

A new EDX system, consisting of multiple SDDs has been developed for an FEI 200kV TEM/STEM in which the SDDs, designed by PN Sensor with a total collection angle approaching 1 srad has been obtained by placing 4 SDD's symmetrically around the electron beam axis in the objective lens chamber. The massive increase in solid angle of collection compared to previous designs in S/TEMs leads to a huge reduction in the time for EDX mapping. First results from the detector are reported.
Structural Applications for General Use (2002)

This chapter contains sections titled: Introduction Attributes of Intermetallic Compounds in Structural Applications for General Use Processing Technologies Fabrication Methods Applications How to Purchase Intermetallics Conclusions Future Needs Acknowledgments Bibliography
Difficulties of T1 brain MRI segmentation techniques (2002)

This paper looks at the difficulties that can confound published T1-weighted Magnetic Resonance Imaging (MRI) brain segmentation methods, and compares their strengths and weaknesses. Using data from the Internet Brain Segmentation Repository (IBSR) as a gold standard, we ran three different segmentation methods with and without correcting for intensity inhomogeneity. We then calculated the similarity index between the brain masks produced by the segmentation methods and the mask provided by the IBSR. The intensity histograms under the segmented masks were also analyzed to see if a Bi-Gaussian model could be fit onto T1 brain data. Contrary to our initial beliefs, our study found that intensity based T1-weighted segmentation methods were comparable or even superior to, methods utilizing spatial information. All methods appear to have parameters that need adjustment depending on the data set used. Furthermore, it seems that the methods we tested for intensity inhomogeneity did not improve the segmentations due to the nature of the IBSR data set.
Superhydrophobic silica aerogel microspheres from methyltrimethoxysilane: rapid synthesis via ambient pressure drying and excellent absorption properties (2013)

Silica aerogels are nanostructured porous solids with an open pore structure, high surface area, high porosity, low bulk density, and low thermal/electrical conductivity, which have drawn great interest in both science and technology. Generally, silica aerogels are prepared via a sol–gel process with a subsequent drying step, in which a supercritical condition is usually employed to dry wet silica gels. However, the supercritical drying is a limiting factor for synthesis efficiency and cost. Ambient pressure drying (APD) is considered an alternative and more practical approach. However, the tedious surface modification and solvent exchange steps involved in conventional APD for the synthesis of silica aerogels (bead- or bulk-type) are still challenges. In this study, a novel APD method was successfully developed for the drying of precursor silica microspheres that were obtained via a water-in-oil (W/O) emulsion method using methyltrimethoxysilane (MTMS). The resultant silica aerogel microspheres were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and the Brunauer–Emmett–Teller (BET) method. The results indicate that silica aerogel microspheres possess similar characteristics to those aerogels prepared by supercritical drying. The silica aerogel microspheres have a mean diameter of approximately 300 μm, a bulk density as low as 0.08 g cm−3, a specific surface area as high as 853 m2 g−1, a pore size distribution between 2 and 45 nm, and an average pore size of 16 nm. In addition, the aerogels are superhydrophobic with a contact angle as high as 172°, and they exhibit excellent absorption capability and recyclability for organic liquids and oils. A new production route for silica aerogel microspheres will greatly expand the commercial utilization of these materials.
The Diagnosis of Photosensitivity (2000)

Many photosensitive patients are seen for consultation when they have no lesions, so a detailed history is important. The differential diagnosis is based on the age at which the symptoms first occurred. The striking symptoms and signs are discussed, and advice is given on which additional investigations are necessary and when phototesting must be performed. Guidelines are also given for the performance of phototesting with simple light sources.
Loop Diuretics Combined with an ACE Inhibitor for Treatment of Hypertension (1989)

Both angiotensin converting enzyme (ACE) inhibition and sodium-diuresis lower blood pressure in spontaneously hypertensive rats (SHR). The purpose of the present study was to examine whether long-term therapy with ramipril (RA, and ACE inhibitor) would lower blood pressure more effectively and without adverse reactions in combination with the loop diuretics piretanide (PI) or furosemide (FU). Groups of 15 SHR each were treated once daily for 3 weeks by gavage with 1 and 10 mg/kg RA, 2 and 4 mg/kg PI, and 8 and 16 mg/kg FU alone and with 1 mg/kg RA in combination with each of these diuretics at both the high and low doses. Sustained and marked ACE inhibition with 10 mg/kg RA normalized BP, but this was accompanied with slightly impaired kidney function as assessed by increases in both urea and creatinine. Low-dose diuretic therapy, producing little diuresis, or treatment with 1 mg/kg RA, producing less sustained ACE inhibition were less effective on blood pressure and scarcely altered serum solute levels, except 4 mg/kg PI, which produced slight reductions in Na+, K+, Mg2+, and PO4(3-). Combined treatment with the 1 mg/kg RA with either diuretic given at low or high dose was well tolerated at much improved reduction in blood pressure compared to their effects individually and without changes in serum solute concentrations and without hemoconcentration. Thus, combined treatment with low doses of loop diuretics and ACE inhibitors that permit partial recovery of serum ACE activity during the 24 h after dosing synergistically lowers blood pressure without adverse reactions associated with larger doses of either therapy alone.
Changes in Plasma Lipids and Lipoproteins during Isotretinoin Therapy for Acne (1985)

Abnormalities in plasma lipids are a recognized side effect of isotretinoin therapy for nodulocystic acne. We studied 60 patients during 20 weeks of isotretinoin therapy, to measure changes in plasma lipids and lipoproteins, to compare plasma lipid responses in men and women, and to determine whether there are alterations in levels of lipoprotein lipase or hepatic triglyceride lipase that could explain the development of isotretinoin-induced hypertriglyceridemia. Mean triglyceride levels rose in men and women, with maximum mean increases of 46.3 mg per deciliter (P less than 0.0001) and 52.3 mg per deciliter (P less than 0.002), respectively. The maximum level was reached by 4 weeks of therapy in men but not until the 12th week in women. Nine of 53 patients (17 per cent) completing 20 weeks of isotretinoin therapy acquired hypertriglyceridemia, with values of 200 to 600 mg per deciliter. Both men and women had significant increases in mean plasma levels of cholesterol and low-density-lipoprotein cholesterol and decreases in mean levels of high-density-lipoprotein cholesterol. There were no significant changes in mean levels of lipoprotein lipase or hepatic triglyceride lipase. Plasma lipid and lipoprotein levels returned to base line by eight weeks after discontinuation of the drug. If sustained over a long period, the change in the ratio of low-density-lipoprotein cholesterol to high-density-lipoprotein cholesterol that we observed, from 2.4 to 3.0 (P less than 0.0001), would predict an increased risk of cardiovascular disease.
Insights into drug delivery across the nail plate barrier (2014)

Topical therapy is at the forefront in treating nail ailments (especially onychomycosis and nail psoriasis) due to its local effects, which circumvents systemic adverse events, improves patient compliance and reduces treatment cost. However, the success of topical therapy has been hindered due to poor penetration of topical therapeutics across densely keratinized nail plate barrier. For effective topical therapy across nail plate, ungual drug permeation must be enhanced. Present review is designed to provide an insight into prime aspects of transungual drug delivery viz. nail structure and physiology, various onychopathies, techniques of nail permeation enhancement and in vitro models for trans-nail drug permeation studies. Updated list of drug molecules studied across the nail plate and key commercial products have been furnished with sufficient depth. Patents pertinent to, and current clinical status of transungual drug delivery have also been comprehensively reviewed. This is the first systematic critique encompassing the detailed aspects of transungual drug delivery. In our opinion, transungual drug delivery is a promising avenue for researchers to develop novel formulations, augmenting pharmaceutical industries to commercialize the products for nail disorders.