Miracle-dz/UniFAR-FTUs huggingface dataset:
Orally active and selective benzylidene ketal M2 muscarinic receptor antagonists for the treatment of Alzheimer's disease

Numerous studies have implicated the cholinergic system as a target for Alzheimer's disease (AD) therapy. The currently marketed drugs for treatment of AD are acetylcholinesterase inhibitors, which increase levels of the neurotransmitter acetylcholine (ACh) by blocking its metabolic degradation. However, this mechanism results in a non‐selective enhancement of cholinergic activity in peripheral organs as well as brain, which could lead to detrimental side effects. Cholinergic enhancement in brain can also be achieved by blocking presynaptic release‐regulating autoreceptors. M2 muscarinic receptor activation inhibits ACh release in brain regions that are critical for learning and memory processes. Thus, M2 antagonists may prove beneficial for relief of cognitive deficits in AD. In this review, early discoveries of M2 muscarinic antagonists based on dibenzodiazepinones, natural products, piperazines, and piperidines are described. More specifically, the development of a benzylidene ketal class of M2 muscarinic antagonists is reviewed. Characterization and optimization of these agents have led to the identification of compounds with high M2 receptor affinity and subtype selectivity. These M2 antagonists also facilitate ACh release and enhance cognition in preclinical experimental paradigms. While clinical efficacy of these compounds has not been evaluated, M2 antagonists represent a promising treatment for AD. Drug Dev. Res. 56:310–320, 2002. © 2002 Wiley‐Liss, Inc.
XPS study of finely dispersed iron powders modified by radiation-grafted acrylamide

X-ray photoelectron spectroscopy was used to investigate structural peculiarities of the modifying layer obtained by means of radiation grafting of acrylamide (AA) on the surface of finely dispersed iron powder (FDIP) with a stabilizing coating based on oleic acid and isophytol. Judging by the information obtained on the grafting degree of AA, the highest grafting degree has been attained with water used as the monomer solvent (direct technique). The reasons for the grafting failure while using ‘the hydroperoxide technique’ have been discussed. Based on the XPS data, the mechanism of AA grafting from water solution to the surface of FDIP with a stabilizing coating has been proposed. The grafting process has been assumed to be associated with the formation of linear chains, including several types of reactive N- and O-containing groups at the active sites of the FDIP stabilizing layer. Such active sites are presumably represented by Fe(III), which are the central atoms of the complex compounds on the outer surface of the stabilizing coating. Polyacrylamide-grafted chains with hydrophobic radicals and a set of polar groups replace some of the monomer ligands around Fe(III) in the process of grafting. This process is most likely followed by the formation of chelate structures. The use of a chemical derivatization technique has provided insight into the nature of the peaks in the region of 284 eV in the C 1s spectra. The appearance of these peaks results from the formation of ‘quasi-graphite’ structures by isolated CC bonds present in a closely packed, highly oriented, stabilizing coating of iron powders under study. Copyright © 2000 John Wiley & Sons, Ltd.
Oxidation of Silicon Using Electron Cyclotron Resonance Nitrous Oxide Plasma and Its Application to Polycrystalline Silicon Thin Film Transistors

Electron cyclotron resonance nitrous oxide (N 2 O) plasma oxidation has been investigated as a process to grow thin oxide on polycrystalline silicon and (100), (111), and (110) oriented crystalline silicon. In spite of a low thermal budget, N 2 O plasma oxidation incorporates nitrogen atoms at the silicon/silicon dioxide interface and forms a nitrogen-rich layer. The incorporated nitrogen atoms are tightly bound to silicon atoms at the interface with N (Is) electron energy of 397.8 eV. The oxidation rate in N 2 O plasma is less dependent on crystalline orientation in comparison with thermal O 2 , and is therefore nearly identical in poly- and single-crystalline-Si. Polysilicon oxide (polyoxide) grown by N 2 O plasma oxidation exhibits better electrical properties than thermally grown oxides; this is attributed to the smooth interface between the polyoxide and a poly-Si film. Polysilicon thin film transistors fabricated with N 2 O plasma oxide show improved performance, which is attributed not only to the smooth interface but also to oxygen- and nitrogen-plasma passivation.
Denitrification in sediment determined from nitrogen isotope pairing

A new method for accurate and easy measurement of denitrification in sediments is presented. The water overlying intact sediment cores was enriched with 15NO3− which mixed with the 14NO3− of the natural sources of NO3−. The formation by denitrification of single-labeled (14N15N) and double-labeled (15N15N) dinitrogen pairs was measured by mass spectrometry after a few hours incubation. Total denitrification including the formation of unlabeled (14N14N) dinitrogen could be calculated assuming random isotope pairing by denitrification of the uniformly mixed NO3− species. In contrast to previous approaches, by this method it is possible to measure denitrification of both NO3− diffusing from the overlying water and NO3− from nitrification within the sediment.
Using Amide 1H and 15N Transverse Relaxation To Detect Millisecond Time-Scale Motions in Perdeuterated Proteins: Application to HIV-1 Protease

Measurements of proton transverse relaxation rates, R2 and R1ρ, have not been commonly performed for proteins because cross correlations among the numerous 1H−1H dipolar interactions complicate analysis of the data. In addition, these interactions make large contributions to the relaxation of the amide protons, making it difficult to detect if an exchange of chemical shifts also makes a contribution, Rex, to relaxation. To overcome these problems, we have investigated proton relaxation of a perdeuterated protein, HIV-1 protease, bound to a small protonated inhibitor DMP323. Perdeuteration significantly reduces the contributions of 1H−1H dipolar interactions to the relaxation of the amide protons. The ROESY R1ρ experiment further reduces the overall relaxation rate as compared with the usual R1ρ experiment because the protons relax as unlike spins, with rate R1ρ,unlike, in the former experiment but as like spins, with rate R1ρ, in the latter. These reductions of the proton transverse-relaxation rate facili.
A new method for surface analysis of crystals using X-ray diffraction under the specular reflection conditions

A new method is suggested for simultaneous determination of small misorientations of the surface from the chosen crystallographic plane and the thickness of the surface amorphous layer. The method is based on X-ray diffraction experiments under specular reflection conditions. The determination of misorientation consists of the comparison of diffraction curve intensities for hkl and {\bar h}{\bar k} {\bar l} reflections obtained from the plane normal to the crystallographic plane along which the crystal surface is cut. The accuracy of the determination exceeds the accuracy known for other methods. The amorphous layer is considered to be either an oxide film or any other disordered layer having no crystal structure. The layer thickness is determined from the consideration of the diffraction curve shapes using comparison with theoretical calculations. The method provides detection of layers ~5 A in thickness, which seems to be unique for X-ray diffraction methods. The method may find wide application in the surface analysis of perfect crystalline specimens, in particular, of materials used in semiconductor microelectronics.
The Antiviral Role of Green Tea Polyphenols

Over the centuries, infectious diseases caused by viruses have seriously threatened human health globally. Viruses are responsible not only for acute infections but also many chronic infectious diseases. To prevent diseases caused by viruses, the discovery of effective antiviral drugs, in addition to vaccine development, is important. Green tea catechins (GTCs) are polyphenolic compounds from the leaves of Camellia sinensis. In recent decades, GTCs have been reported to provide various health benefits against numerous diseases. Studies have shown that GTCs, especially epigallocatechin-3-gallate (EGCG), have antiviral effects against diverse viruses. The aim of this review is to summarize the developments regarding the antiviral activities of GTCs, to discuss the mechanisms underlying these effects and to offer suggestions for future research directions and perspectives on the antiviral effects of EGCG.
Inhomogeneity of Mixing in Acetonitrile Aqueous Solution Studied by Small-Angle X-ray Scattering

Acetonitrile aqueous solution has an upper critical solution temperature (UCST) at 272 K at c = 0.38 (c represents the mole fraction of acetonitrile). To study quantitatively how the mixing scheme of the solution changes as a function of concentration and temperature, the concentration fluctuation, the Kirkwood-Buff parameters, and individual density fluctuations for acetonitrile and water were obtained by means of small-angle X-ray scattering experiments at 273, 279, and 298 K in the range of 0.0 ≤ c ≤ 0.5. The values of concentration fluctuation became larger close to UCST and exhibit a maximum at c = 0.38. The mixing scheme of acetonitrile aqueous solution is discussed from the point of view of inhomogeneity of molecular distribution.
Synthesis and characterization of 1, 1-bis (3-methyl-4-epoxyphenyl) cyclohexane-toughened DGEBA and TGDDM organo clay hybrid nanocomposites

1,1-bis (3-methyl-4-epoxyphenyl) cyclohexane (BMEPC) was synthesized from 1,1-bis (3-methyl-4-hydroxyphenyl) cyclohexane and 2-(chloromethyl) oxirane, and its structure was confirmed by Fourier transform infrared (FT-IR), 1H-, 13C-NMR and electron impact-mass spectrometry. Both diglycidyl ether of bisphenol-A (DGEBA) and tetraglycidyl diamine diphenyl methane (TGDDM) epoxy resins were toughened with BMEPC using 4,4′-diaminodiphenylmethane (DDM) as a curing agent. Epoxy and BMEPC-toughened epoxy systems were further modified with organophilic MMT (OMMT) clay. The chemical reactions involved between epoxy and DDM with OMMT was confirmed by FT-IR. OMMT clay-filled hybrid BMEPC-epoxy resin castings were characterized for their mechanical, thermal, thermo-mechanical and morphological properties. The values of Tg and heat distortion temperature of hybrid epoxy decreased with increasing incorporation of OMMT. The data obtained from thermal studies indicated that the incorporation of nano clay into BMEPC-modified hybrid systems possess improved thermal stability. The mechanical properties were studied as per ASTM standards. The TGDDM-based hybrid epoxy system exhibited higher values of tensile and flexural properties than that of the DGEBA hybrid epoxy system, whereas the impact strength of the DGEBA system was higher when compared with that of the TGDDM system. The values of dielectric constant (ϵ′) and dielectric loss (ϵ′′) were increased with increased incorporation of OMMT clay in both systems. From the X-ray diffraction analysis it was observed that the absence of d001 reflections in OMMT-filled BMEPC-modified epoxy systems indicated the formation of exfoliated nano hybrids. The homogenous morphologies were ascertained from scanning electron microscope and transmission electron microscope.
Effect of Surfactant Agents on the in Vitro Release of Insulin from DL-PLA Microspheres

This paper describes the effect of surfactants on the in vitro release profile of bovine insulin from DL-polyacetic acid (DL-PLA) microspheres prepared by the double-emulsion technique. The surfactants, Tween®-80 and Span®-60, were included in the water and oil phases, respectively, of the first emulsion. The presence of these agents affected the burst effect but not the subsequent release phase. The latter is more controllable by PLA molecular weight selection, with slower release being achieved as the molecular weight increases.
A Comparison of the Rates of Fe(III) Reduction in Synthetic and Bacteriogenic Iron Oxides by Shewanella putrefaciens CN32

The susceptibility of various bacteriogenic iron oxides (BIOS) to bacterial Fe(III) reduction was examined. Reduction resulted in complete dissolution of the iron mineral from the surfaces of the Fe-oxidizing consortium. Reduction rates were compared to that of synthetic ferrihydrite (HFO). The reduction rate of HFO (0.162 day− 1) was significantly lower than that of Äspö (Gallionella dominated) BIOS (0.269 day− 1). Two Canadian (Leptothrix dominated) BIOS samples showed statistically equivalent rates of reduction (0.541 day−1 and 0.467 day− 1), which were higher than both Äspö BIOS and HFO. BIOS produced by different iron-oxidizing genera have different susceptibilities to microbial reduction.
Preparation and characterization of polyurethane electrical insulating coatings derived from novel soybean oil‐based polyol

As a viable alternative to the petrochemical polyols in polyurethanes (PUs), a new soybean oil-based polyol (PSBO) with high functionality of hydroxyl groups and built-in (preformed) urethane bonds was introduced. At first, a facile and improved method was developed for the transformation of epoxidized soybean oil (ESBO) to carbonated soybean oil (CSBO). Then ring-opening reaction of carbonated oil with ethanolamine (ETA) led to the polyol. After characterization by conventional spectroscopic and analytical methods, PSBO was used for the formulation of novel one-pack PU electroinsulating wire enamels. Tunable mechanical, thermal, and electrical properties for the final PUs were achieved by replacing 10 wt% of PSBO with poly(propylene glycol) (PPG) at different number average molecular weights of 725, 1000, 2000, 4000. Investigation of the results showed that these soy-based PUs offer excellent thermal and electrical insulating properties. Copyright © 2009 John Wiley & Sons, Ltd.
Structure, folding, and energetics of cooperative interactions between the beta-strands of a de novo sesigned three-stranded antiparallel beta-sheet peptide

The effect of cooperative interactions between β-strands in enhancing β-sheet stability has been examined quantitatively by NMR using rationally designed synthetic peptides [β-hairpin (2β) and related 24-residue three-stranded antiparallel β-sheet (3β)] which are significantly folded in aqueous solution. The two hairpin components of 3β show quite different temperature-dependent stability profiles showing that a two-state model for folding (random coil ↔ three-stranded antiparallel β-sheet) is inappropriate. A four-state model for folding, involving intermediate C- and N-terminal β-hairpin conformations, is more consistent with the data. Thermodynamic analysis shows that folding of the C-terminal hairpin of 3β is entropy-driven, as previously described for the isolated hairpin 2β, but that the N-terminal hairpin, which is stabilized by a motif of aromatic residues (W4, F6, and Y11), is enthalpy-driven, consistent with stabilization through π−π interactions that are electrostatic in origin. NOE data, as we.
Adsorption of Gas Molecules on Graphene Nanoribbons and Its Implication for Nanoscale Molecule Sensor

We have studied the adsorption of gas molecules (CO, NO, NO2, O2, N2, CO2, and NH3) on graphene nanoribbons (GNRs) using first principles methods. The adsorption geometries, adsorption energies, charge transfer, and electronic band structures are obtained. We find that the electronic and transport properties of the GNR with armchair-shaped edges are sensitive to the adsorption of NH3, and the system exhibits n-type semiconducting behavior after NH3 adsorption. Other gas molecules have little effect on modifying the conductance of GNRs. Quantum transport calculations further indicate that NH3 molecules can be detected out of these gas molecules by the GNR-based sensor.
Cyclopentapeptides as Flexible Conformational Templates

Studies of 3D models for cyclopentapeptides (CPP's) employing only NMR spectroscopy encounter a serious problem. Because of conformer averaging, 3D structure(s) derived directly from NMR data may not correspond to the energy minimum (minima) with low relative conformational energy. At the same time, independent energy calculations can determine all low-energy conformers for the CPP backbone. The two approaches are compared in this study by results obtained for cyclo(d-Pro1-Ala2-Ala3-Ala4-Ala5). Contrary to the conclusion (predominance of the βII‘γ type conformer) of earlier NMR studies, independent energy calculations found a different family of low-energy 3D structures that are consistent both with the NMR data in DMSO and with the known X-ray data on CPP's. The preferable Ala4 conformations were found in the αR/αL regions suggesting studies of cyclo(d-Pro1-Ala2-Ala3-Aib4-Ala5) which was synthesized. Further NMR studies confirmed the results of the independent energy calculations. The independent energy .
Numerical simulation of roadway gas migration based on the lattice Bolzmann method

College of Resources and Environmental Engineering, Key Laboratory of Ministry of Education for Mine Disaster Prevention and Control, Shandong University of Science and Technology, Qingdao, Shandong 266590,China Abstract Coal roadway tunneling could result in redistribution of stresses in the coal body around the roadway, and cause the spatially uneven distribution of permeability in the coal body around roadway both in the radial direction and the axial direction. Considering this engineering fact and using the lattice Boltzmann method, the migration law of the gas is studied in the coal body around the roadway. Research shows that: as time goes on, the gas pressure dropped area of the coal body will gradually increases; along the radical direction of the roadway, the gas pressure gradient in the coal body closer to the roadway wall would gradually decrease, whereas the gas pressure gradient in the coal body farther from the roadway wall would gradually increase, and at the locations with stress concentration and low permeability, because the gas flow is easily blocked, it would be likely to cause a higher gas pressure gradient; the model for calculating the gas emission quantity of the roadway is given, and the calculated results can provide the basis for the ventilation design of the roadway.
Enhancement of crystalline perfection by organic dopants in ZTS, ADP and KHP crystals as investigated by high‐resolution XRD and SEM

To reveal the influence of complexing agents on crystalline perfection, tristhiourea zinc(II) sulfate (ZTS), ammonium dihydrogen phosphate (ADP) and potassium hydrogen phthalate (KHP) crystals grown by slow-evaporation solution growth technique using low concentrations (5 x 10 -3 M) of dopants like ethylenediamminetetraacetic acid (EDTA) and 1,10-phenanthroline (phen) were characterized by high-resolution X-ray diffractometry (XRD) and scanning electron microscopy (SEM). High-resolution diffraction curves (DCs) recorded for ZTS and ADP crystals doped with EDTA show that the specimen contains an epilayer, as observed by the additional peak in the DC, whereas undoped specimens do not have such additional peaks. On etching the surface layer, the additional peak due to the epilayer disappears and a very sharp DC is obtained, with full width at half-maximum (FWHM) of less than 10 arcsec, as expected from the plane wave dynamical theory of X-ray diffraction for an ideally perfect crystal. SEM micrographs also confirm the existence of an epilayer in doped specimens. The ZTS specimen has a layer with a rough surface morphology, having randomly oriented needles, whereas the ADP specimen contains a layer with dendric structure. In contrast to ADP and ZTS crystals, the DC of phen-doped KHP shows no additional peak, but it is quite broad (FWHM = 28 arcsec) with a high value of integrated intensity, p (area under the DC). The broadness of the DC and the high value of p indicate the formation of a mosaic layer on the surface of the crystal. However, similar to ADP and ZTS, the DC recorded after etching the surface layer of the KHP specimen shows a very sharp peak with an FWHM of 8 arcsec. An SEM photograph of phen-doped KHP shows deep cracks on the surface, confirming the mosaicity. After removing the surface layer, the SEM pictures reveal a smooth surface. A similar trend is observed with other complexing agents, like oxalic acid, bipy and picolinic acid. However, only typical examples are described in the present article where the effects were observed prominently. The investigations on ZTS, ADP and KHP crystals, employing high-resolution XRD and SEM studies, revealed that some organic dopants added to the solution during the growth lead to the formation of a surface layer, due to complexation of these dopants with the trace metal ion impurities present in the solution, which prevents the entry of impurities, including the solvent, into the crystal, thereby assisting crystal growth with high crystalline perfection. The influence of organic dopants on the second harmonic generation efficiency is also investigated.
Self‐Consistent Field Theory for the Electronic Structure of Polymers

A general SCF–SCAO theory for computations of the electronic structure in polymeric species is presented. The theory is essentially a tight‐binding model expressed in a manner close to the self‐consistent field–LCAO matrix formalism and restricted to closed‐shell cases. Particular care has been taken to ensure a theory which can be easily applied in practical applications. A computer program, polymol, has been programmed and a short description is included at the end of this paper. Throughout the paper reference is given to the (H2) infinite chain, as an example.
Hydrogen-bonded frameworks of propylenediamine-N,N′-diacetic acid Pt(II) complexes, synthesis, structural characterization, and antitumor activity

Two Pt(II) complexes of propylenediamine-N,N′-diacetic acid (H2pdda) have been synthesized in which H2pdda is bidentate and tetradentate. The two complexes, [Pt(C7H14N2O4)Cl2] (1) and [Pt(C7H12N2O4)] (2), have been characterized by elemental analysis, IR, mass spectroscopy, and thermal (TGA and DTG) analysis. The crystal structure of 1 and [Pt(C7H12N2O4)]·3H2O (2a) are reported. In vitro cytotoxic properties of 1 and 2 were evaluated against HEPG2 (liver carcinoma cell lines) and HCT116 (colon carcinoma cell lines), and were compared with the standard anticancer drugs cisplatin (cis-DDP) and doxorubicin (Dox). The obtained data indicate that the two complexes show weak cytotoxic activity against the two tested cell lines, except for 1 which revealed a relatively high activity against HEPG2. Structure–activity relationships have been interpreted. Graphical Abstract
Effect of Root Density on Erosion and Erodibility of a Loamy Soil Under Simulated Rain

Abstract Although both aboveground and belowground components of vegetation act together in reducing soil erosion, mainly the aboveground component has received attention in past research. The aim of this study was to evaluate the contribution of roots in soil erosion control and the effect of root density in soil erodibility and soil physical properties. Perennial ryegrass (Lolium perenne L. Hugo) was grown in soil pans, and laboratory rainfall simulation experiments were conducted after 4, 8, 12 weeks of their growth with seeding density of 50 kg ha−1, after 4 weeks for seeding density of 100 kg ha−1, and on a control. The experiments with ryegrass were done in the presence of complete plants and after clipping off the shoots. Roots of ryegrass grew rapidly, attaining densities of 0.614 kg m−2 and 2.280 kg m−2 in 4 and 12 weeks, respectively. With increasing root density, splash and wash decreased exponentially. There was positive correlation between soil shear strength and root density, but no influence of roots on bulk density and saturated hydraulic conductivity was observed.