Miracle-dz/UniFAR-FTUs huggingface dataset:
Atomic-Level Description of Amyloid β-Dimer Formation

All-atom simulations have been carried out on a monomer and dimer of the aggregation-prone fragment (16−22) of amyloid β peptide, which is implicated in Alzheimer's disease. The replica exchange molecular dynamics method, which has been successfully applied to peptide folding, is utilized as a means to sample the configurational space with proper Boltzmann weighting so that the structural, motional, and thermodynamic description of self-assembly can be obtained. The free energy landscape showing the delicate balance between different monomer and dimer conformations is mapped along carefully chosen reaction coordinates. The canonical ensembles at 38 different temperatures are used to describe the thermodynamics and the relative stabilities of at least six different dimer conformations including that of parallel and antiparallel orientations. We also delineate the nature of the molecular forces that activate and stabilize these different dimer conformations as a function of temperature, especially as relate.
Picosecond Transient Infrared Spectrum of 4-(Dimethylamino)benzonitrile in the Fingerprint Region

The picosecond time-resolved infrared spectrum of 4-(dimethylamino)benzonitrile (DMABN) has been recorded in the fingerprint region in acetonitrile solution. Several induced infrared bands have been obtained. From the temporal behavior of the band intensities, the induced bands have been attributed to the S1 state of DMABN that is believed to be an intramolecular charge-transfer excited state. Vibrational assignments of the observed bands and the molecular structure of the S1 species are discussed. Most of the strong bands have been found in the single bond wavenumber region. From this result, the ring C−NMe2 bond is considered to retain a single bond character in the S1 state. No distinct infrared band that can be assigned to the locally excited state of DMABN has been observed. Measurements are also tried for 4-aminobenzonitrile in acetonitrile, but no induced infrared band has been found.
An algebraic study of non classical fullerenes

Abstract The Wiener index is the oldest topological index based on the sum of distances between any pair of vertices in given graph. An algebraic approach for generalizing the Wiener index was proposed by Graovać and Pisanski for the first time. In this paper, we compute the modified Wiener index and then the differences between Wiener and modified Wiener indices of an infinite class of non-classical fullerenes.
EFFECT OF CONTINUOUS AND INTERMITTENT AERATION ON COMPOSTING OF POULTRY LITTER AND COTTON STALKS

The present study was carried out at Rice Mechanization Center, Meet El-Deeba, Kafrelsheikh governorate, Egypt during the year of 2013. The influence of forced aeration modes (continuous and intermittent aeration) at three levels of aeration rates of 0.13, 0.16 and 0.19m 3 /h on composting of poultry litter and cotton stalks were studied using metal vessels. Three various levels of intermittent aeration (45, 30 and 15min/h) were tested. Temperature was monitored and recorded as the most important indicator of the efficiency and effectiveness of the composting process. Also, the moisture content and Carbon:Nitrogen (C:N) ratio of the initial composting mixture were adjusted at about 61.53% and 32:1, respectively. The moisture content and pH value were measured during composting process. Total organic matter, bulk density, electrical conductivity, total nitrogen and total organic carbon were measured on the initial composting mixture and at the final composting product. Moreover, the most important results showed that the maximum temperature of 65.45 o C (at thermophilic phase) was recorded after twenty-six days from the beginning of composting time at the intermittent aeration of 30min/h and the aeration rate of 0.16m 3 /h. In all vessels the moisture content and C:N ratio decreased and were proportional to temperature and aeration conditions. However, the lowest time for cooling down and maturing compost was of sixty-four days at 30min/h and 0.16m 3 /h aeration conditions. The initial bulk density of the mixture compost materials decreased from 34.8 to 13.9% at the end composting process depending on the aeration conditions.
Tidal and Fluvial Influence on Shallow Groundwater Fluctuation in Coastal Wetlands in Yellow River Delta, China

In coastal wetland, groundwater is influenced by both tidal processes and land hydrological processes. To study the influences of tidal processes and river runoff on the shallow groundwater dynamic in coastal wetland of the Yellow River Delta, surface and shallow groundwater depth were monitored. It was found that in the east part of the study area where close to the shoreline, surface is characteristic of obvious periodicity, the fluctuation of surface water was mainly controlled by tidal processes. As to the shallow groundwater, fluctuation of water depth is also influenced by the tidal process and has obvious periodicity similar to the surface water. In the north part of the study area, the shallow groundwater is mainly influenced by the Yellow River runoff. The influence distance of tidal processes and river runoff on shallow groundwater system is 14700 and 11600m, respectively.
Determination of Active Ingredients of Spatholobus Suberectus Dunn and Its Medicinal Preparations by Capillary Electrophoresis with Electrochemical Detection

Abstract A method based on capillary electrophoresis with electrochemical detection has been developed for the separation and determination of epicatechin, emodin, syringic acid, vanillic acid, rhein, and protocatechuic acid in Spatholobus suberectus dunn and its medicinal preparations for the first time. The effects of a working electrode potential, pH and concentration of running buffer, separation voltage, and injection time on CE‐ED were investigated. Under the optimum conditions, the analytes could be separated in a 60 mmol L−1 borate buffer (pH 9.0) within 26 min. A 300 µm diameter carbon disk electrode has a good response at +0.95 V (vs. SCE) for all analytes. The response was linear over three orders of magnitude with detection limits (S/N=3) ranging from 5×10−8 g mL−1 to 2×10−7 g mL−1 for the analytes. The method has been successfully applied to the analysis of a real sample, with satisfactory results.
Packing polymorphism of a conformationally flexible molecule (aprepitant)

This work highlights the structural and thermochemical differences of two modifications of the NK1receptor antagonist aprepitant. Form I° is the stable polymorph and crystallises in the orthorhombic space groupP212121 whereas the metastable form II is monoclinic (space groupP21). The monotropically related polymorphs show only minor differences in melting point and heat of fusion (Tfus,I = 253.6, ΔfusHI = 53.7 kJ mol−1, Tfus,II = 253.0 °C, ΔfusHII = 52.4 kJ mol−1) and often crystallise concomitantly. The forms exhibit a very close structural relationship based on a common 2D packing fragment, which is in fact a stack of 1D N–H⋯O hydrogen bonded ribbon chains. Forms I° and II may therefore be interpreted as two distinct stacking modes of this common 2D unit. The alternative modes are associated with slight differences in weaker intermolecular interactions. Somewhat surprisingly, the aprepitant molecule adopts almost the same conformation in the two crystal structures in spite of its potential conformational flexibility. Hirshfeld surface analysis was successfully deployed to visualise and elaborate the small differences in the molecular environments of the two polymorphs. The study emphasises the benefit of single-crystal structure data for the judgement of the phase purity and of polymorphs exhibiting only weak energetical and structural differences.
Preparation of TiO2 aerogels by a sol-gel combined solvothermal route

TiO2 (anatase) aerogels with high surface area were prepared through solvothermally treating the TiO2 based wet-gels prepared by the sol-gel method, followed by atmosphere-drying to remove the solvents from the gels. This route provided a new strategy for the preparation of crystalline metal oxide aerogels. The microstructure of the aerogel was studied in detail. The aerogels solvothermally treated at 140 °C exhibited a high BET surface area of 528.9 m2/g. All the aerogels showed extensive photoluminescent emission at 467, 555 and 615 nm, whose intensity decreased with the solvothermal temperature increasing and significantly increased after calcinations.
From weak to strong interactions: A comprehensive analysis of the topological and energetic properties of the electron density distribution involving X–H⋯F–Y systems

The topological and energetic properties of the electron density distribution ρ(r) of the isolated pairwise H⋯F interaction have been theoretically calculated at several geometries (0.8<d<2.5 A) and represented against the corresponding internuclear distances. From long to short geometries, the results presented here lead to three characteristic regions, which correspond to three different interaction states. While the extreme regions are associated to pure closed-shell (CS) and shared-shell (SS) interactions, the middle one has been related to the redistribution of ρ(r) between those electronic states. The analysis carried out with this system has permitted to associate the transit region between pure CS and SS interactions to internuclear geometries involved in the building of the H–F bonding molecular orbital. A comparative analysis between the formation of this orbital and the behavior of some characteristic ρ(r) properties has indicated their intrinsic correspondence, leading to the definition of a b.
Complete Destruction of p-Nitrophenol in Aqueous Medium by Electro-Fenton Method

An indirect electrochemical method, which is very efficient for the degradation of organic pollutants in water, is described. The method, named electro-Fenton, is based on electrocatalytical generation of Fenton's reagent to produce hydroxyl radicals, which are very active toward organic compounds. An industrial pollutant, p-nitrophenol (PNP), was chosen for this study and was eventually mineralized. The major intermediary degradation products such as hydroquinone, benzoquinone, 4-nitrocatechol, 1,2,4-trihydroxybenzene and 3,4,5-trihydroxy- nitrobenzene were unequivocally identified by HPLC and GC-MS methods. The rate constants of the hydroxylation reactions were determined. The mineralization of the initial pollutant and the intermediates formed during electro-Fenton treatment was followed by total organic carbon (TOC) analyses. Dependence of mineralization on the amount of electrical energy consumed is shown by the relative decrease of TOC values. A mineralization reaction mechanism is proposed.
Curing of DGEBA epoxy resin by low generation amino‐group‐terminated dendrimers

Low generation amino-group-terminated poly(ester-amine) dendrimers PEA1.0 (NH2)3 and PEA1.5 (NH2)8, and poly(amido-amine) dendrimer PAMAM1.0 (NH2)4 were used as diglycidyl ether of bisphenol A (DGEBA) epoxy resin hardeners. Thermal behavior and curing kinetics of dendrimer/DGEBA systems were investigated by means of differential scanning calorimetry (DSC). Compared with ethylene diamine (EDA)/DGEBA system, the dendrimer/DGEBA systems gradually liberated heat in two stages during the curing process, and the total heat liberated was less. Apparent activation energy and curing reaction rate constants for dendrimer and EDA/DGEBA systems were estimated. Thermal stabilities and mechanical properties of cured thermosetting systems were examined as well. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3902–3906, 2006
Mobility of fomesafen and atrazine in soil columns under saturated‐ and unsaturated‐flow conditions

The relative mobilities of 14C-labeled fomesafen and atrazine in Norfolk sandy loam (Typic Paleudult), Drummer silt loam (Typic Haplaquoll). Cape Fear sandy loam, (Typic Umbraquult), and a Brazilian Oxisol clay (Typic Acrustox) were studied using 50 cm of water applied to 30–5-cm soil columns under unsaturated- and saturated-flow conditions. Both herbicides were more mobile in Norfolk sandy loam than in Oxisol clay, Drummer silt loam, or Cape Fear sandy loam. Herbicide mobility was inversely related to organic and humic contents of the soils. Mobility of fomesafen was highly correlated with that of atrazine in the soils. Fomesafen was generally less mobile that atrazine under unsaturated-flow conditions and more mobile under saturated-flow conditions. Liming a Norfolk sandy loam increased, and oven drying decreased, fomesafen mobility.
Palladium-catalysed cross-coupling reactions in the synthesis of some high polarizability materials

Abstract Liquid crystal materials of high optical anisotropy consist of moieties of high electron density in conjugation with each other along the molecular length. Such structures are conducive to convergent synthesis methods. Here we report the synthesis of a range of novel materials by the strategic use of palladium-catalysed cross-coupling methods. In addition to the traditional use of bromide and iodide leaving groups, invaluable use of the triflate leaving group and the importance of selective cross-coupling methods using both arylboronic acids and alkynylzinc chloride derivatives is illustrated. This systematic methodology allows the separate synthesis of the appropriate sub-units that can be efficiently coupled together to provide high overall product yields.
Methods of determining Stress‐Strain Curves by upsetting cylindrical test‐pieces

The upsetting test is mainly used for determining stress-strain curves in the range of high strains. Three modifications of the upsetting test are described: upsetting conventional lubricated specimens, upsetting Rastegaev specimens with end recesses, and upsetting under sticking friction conditions. Each of these procedures offers special advantages. For example, in the Rastegaev test, the specimen remains cylindrical up to a high strain while the work required for friction cannot be neglected. By upsetting under sticking friction conditions, no work is required for friction, but the specimen's shape deviates strongly from that one of a cylinder (barrelling). Proposals are made concerning unified procedures for carrying out the tests. Methoden der Bestimmung von Flieskurven im Zylinderstauchversuch Der Stauchversuch dient vor allem zur Aufnahme von Flieskurven im Bereich hoher Umformgrade. Es werden drei Grundformen des Zylinderstauchversuches beschrieben: Stauchen herkommlicher Proben mit Schmierung, Stauchen von Rastegaev-Proben mit Schmiertaschen und Stauchen mit Haftreibung. Jede der drei Methoden bietet spezifische Vorteile. So bleibt z. B. beim Rastegaev-Versuch die Probe bis zu einem hohen Umformgrad zylindrisch, aber der Beitrag der Reibung zur Gesamtarbeit ist merklich. Demgegenuber ist bei Haftreibung die Reibarbeit gleich Null, aber die Probe weicht stark von der Zylinderform ab (Aufbauchen). Es werden Vorschlage gemacht zur Vereinheitlichung der drei Versuche.
Methyl transfer reactions

Publisher Summary This chapter illustrates an example of a nucleophilic substitution reaction-methyl transfer and applies Marcus theory to this set of reactions. It examines methyl transfers and demonstrates that the application of the Marcus theory breaks new ground on these familiar and hallowed pastures. A number of different probes have been examined for the transition state of methyl transfer reactions. The chapter attempts to deduce a model for the transition state which is consistent for all the different types of data. The answers from the different probes are compared to gauge if there is a model that is consistent with all the data on methyl transfer reactions. The data from the various probes and arguments are also summarized in this chapter.
Exchange-induced terahertz minigap in InAs/GaSb type II and broken-gap quantum wells

We theoretically demonstrate that the exchange effect induced by the carrier-carrier interaction can cause the hybridization of the electron and hole dispersion relations in InAs∕GaSb-based type II and broken-gap quantum well (QW) systems. As a result, a terahertz minigap at the anticrossing points of the conduction and valence bands can be induced by the interlayer electron-hole coupling via the Coulomb interaction. It is shown that the many-body effect is another important source of the hybridization of the dispersion relations in InAs∕GaSb QW systems.
Prostaglandin E1‐immobilized poly(vinyl alcohol)‐blended chitosan membranes: Blood compatibility and permeability properties

A series of membranes are prepared by air drying thin films, which were composed of poly(vinyl alcohol) blended with chitosan [a (1 4)2-amino-2-deoxy-β-D-glucan] (PVA–Chit) in different ratios. The PVA-blended chitosan membranes showed improved strength properties and permeability functions for low-molecular-weight compounds. Nonthrombogenic PVA–Chit (4 : 6) membranes were derived by immobilizing bioactive molecules like PGE1 on heparin-modified membranes, via free radical mechanisms, by N2 plasma. This novel membrane demonstrated good permeability properties for small molecules and showed a dramatic reduction in platelet attachment. The prostaglandin E1-immobilized substrate also indicated an increase in albumin surface attachment and a reduction in fibrinogen binding. This may be one of the parameters for a reduced platelet-surface attachment, which may also improve the blood compatibility of the substrate. It is also postulated that the total water content of membranes need not be the prime factor governing the permeability of solutes through water-swollen membranes. However, many other parameters govern the solute permeability, like the amount of solutes dissolved in bound water and the status of water in the polymer matrix.
Investigations on the alpha-helix to coil transition in HP heterogeneous polypeptides using network rigidity

The alpha-helix to coil transition in homogeneous polypeptides has recently been described using a distance constraint model (DCM) that employs network rigidity as an underlying mechanical interaction. The DCM accounts for intramolecular hydrogen bonding, hydrogen bonding to solvent and hydration. These interactions are parametrized to reflect the dependence on the conformational state of the polypeptide backbone. The DCM is capable of describing both heat and cold denaturation. As a function of temperature from low to high, a generic re-entrant response of a homogeneous polypeptide chain in aqueous solution is predicted to make a transition from coil (hydrated state) to helix and then to coil (disordered state). Here we study the thermodynamic stability of heterogeneous polypeptides that include hydrophobic (H) and polar (P) residue types. We explore the nature of the transition by adjusting the overall HP composition using transfer matrix methods that take into account long-range effects due to network rigidity.
Studies on the reduction of nitric oxide by carbon: the nitric oxide-carbon gasification reaction

The heterogeneous reduction od NO by carbon was studied in a thermogravimetric analysis system, employing both pseudosteady and transient reaction methods. The reaction was studied at temperatures from near ambient up to 1073 K, and at NO partial pressures in the range 1.01-10.1 kPa. A relatively pure carbon derived from phenolic resin was studied. gaseous products of rection were measured. The gasification of carbon by NO involves two parallel processes: (1) somewhat slow desorption of relatively stable surface complexes; (2) processes involving NO attack on active unoccupied sites that results in essentially immediate desorption of gaseous products. The first process controls the overall gasification rate at lower temperatures and is governed by a distribution of desorption activation energies, involving mainly surface oxides that yield CO upon desorption
Bio Prospecting Plant Growth-Promoting Bacteria Isolated from Maize (zea mays l.) Roots

Maize (Zea mays L.) culture has a great importance in several countries, especially in Brazil the third-largest world producer. The increase in maize production has been achieved with a high use of fungicide; however, in view of a more sustainable agriculture plant growth promoting bacteria have been explored aiming for the replacement of chemical fertilizers and biological control. In this study, we investigated the bacterial community isolated from maize roots in order to evaluate their capacity of growth promotion as well as of inhibition of fungal species associated with maize leaf diseases. All isolates evaluated were positive for at least one of the parameters evaluated-growth promotion, enzymatic production or bio control. The best results were observed for Enterobacter sp. LGMB221 and Bacillus sp. LGMB242 that showed the high potential for growth promotion, acting in the early stage of maize seedlings development. Bacillus sp. LGMB152 showed the best enzymatic results, indicating that it might play a role against pathogens, a premise supported by the antagonist activity observed. The next steps involve evaluations under field conditions to confirm if these isolates have biotechnological potential as inoculants for the maize crop. In addition, we suggest that Enterobacter strains LGMB221 and LGMB235 and Escherichia strain LGMB159 might represent new species, indicating the high diversity of bacteria in maize rhizosphere that remains to be determined.