Miracle-dz/UniFAR-FTUs huggingface dataset:
Hydration of Sodium Alginate in Aqueous Solution

Alginates are naturally occurring biocompatible polysaccharides. They have a broad range of applications, mainly in connection to their ability to control the rheology of aqueous solutions. Specifically, addition of a small amount of alginate (10% wt) leads to a ∼100-fold increase in viscosity. Here we explore whether that pronounced retardation of the long-range correlations is accompanied by molecular-level changes of the water structure. We employ viscometry, dielectric spectroscopy (DS) and femtosecond infrared (fs-IR) pump–probe spectroscopy to study water dynamics in sodium alginate solutions. Remarkably, despite the large rheological effects of alginates in solution, the rotational dynamics of water are remarkably similar to those observed in bulk water. Only a small subensemble of water molecules is slowed down significantly, amounting to 6 ± 2 water molecules per saccharide unit. Furthermore, DS measurements reveal an additional ∼5 water molecules to be slowed down by the counterion (Na+). Our re.
How Is the Active Site of Enolase Organized To Catalyze Two Different Reaction Steps

Using a combined ab initio quantum mechanical/molecular mechanical approach developed in our laboratory, we obtained the reaction paths and free energy barriers for the two steps of the reaction catalyzed by enolase. In the first step, the α-proton of the substrate, 2-phospho-d-glycerate (PGA), is removed by Lys345, resulting in an enolic intermediate. In the second step, the β-hydroxyl group leaves the enolic intermediate with the assistance of a general acid, Glu211. The calculated free energies of activation are 13.1 and 9.4 kcal mol-1 for the first and the second step, respectively. The barrier heights are consistent with the reaction rates measured from experiments. The calculations indicate that the electrostatic interactions between the substrate and two divalent metal cations at the active site strongly favor the first step. However, the same metal cations strongly disfavor the second step because the change in charge of the substrate is of an opposite sign compared with that in the first step. We.
Rapid Colorimetric Assay of 5-Aminosalicylate

Abstract The drug 5-aminosalicylate is an anti-inflammatory agent used in the treatment of ulcerative colitis. Recent studies have suggested that the amino substituent plays an important role in both the toxicity and the therapeutic effect of the drug. In view of these findings, a rapid and convenient method of analysis would be useful for monitoring selected patients receiving 5-aminosalicylate. A colorimetric assay based upon schiff base formation with the amino substituent was compared to the ferric nitrate method of salicylate analysis. the results indicate that the arylamine assay is more sensitive than the salicylate method and in contrast to the latter, the absorbance versus substrate curve is linear over clinically relevant concentrations. the arylamine assay is simple, rapid, convenient, and suitable for monitoring procedures where only the measurement of the active drug concentration is required.
FAST CALCULATION OF ELECTROSTATICS IN CRYSTALS AND LARGE MOLECULES

A method is presented for efficient calculation of the electrostatic potential due to the nuclei and the continuous electronic charge distribution in a crystal or a large molecule. Accuracy is under the control of a single tolerance parameter. The computational cost for the calculation of the static potential on the entire grid and for static energy evaluation scales asymptotically as O(N) with a favorable prefactor.
Biologically multifunctional surfaces using plasma polymerization methods

We report on the development of a multilayer system, which allows for specific DNA binding reactions to occur at the surface, but at the same time shows antifouling properties, thus minimizing the nonspecific adsorption of proteins (BSA). The synthesis involves the combination of plasma polymerization and streptavidin-biotin assembly. DNA sensing is achieved using SPFS. Antifouling properties are tailored by controlling the film thickness, together with the effects of the swelling in buffer solution and by the specific surface chemical design. Preliminary hybridization experiments show promising results.
POLARIZATION EFFECTS IN XANES OF LAYERED MATERIALS : ALKALI-GRAPHITE INTERCALATION COMPOUNDS STUDY

X-ray absorption spectra in the near edge region of alkali graphite intercalation compounds are reported. MCg and MCZ4 (M = K, Rb, Cs) compounds are lamellar and their spectra exhibit a high orientation dependence. At each energy, a linear regression analysis of the absorption for different incidence angles ( 0 6 40') permits to obtain the limiting case spectrum 9 = 90". In the case of potassium, where the core hole lifetime is large, implying a small broadening of the spectra, comparison is made with published band structures, showing selection rules effects. Anisotropic media (like surfaces or lamellar compounds) are extensively studied by a lot of techniques. Graphite intercalation compounds is a class of highly anisotropic metals which exhibit a lot of interesting properties [ I ] stagging, 2D phase transition, incommensurability . In this communication, we present XANES spectra of alkali first and second stage compounds: MCg and MC24 (M = K, Rb, Cs) K-edge for potassium and rubidium and L-edges for cesium. The spectra were taken at several angles 0 between the photon beam and the normal to the basal planes of the samples, the rotation axis being normal both to the beam and to the polarization vector. An angular analysis of the data is presented and the results are discussed in connection with published band-structures. Article published online by EDP Sciences and available at http://dx.doi. org/10.1051/jphyscol:19868168 C8-870 JOURNAL DE PHYSIQUE Experiments were performed in transmission mode at the X-ray beam line EXAFS I 1 for KCn and CsCn and EXAFS I for RbCn of LURE-DCI. Since the samples are very air-reactive, they were kept under vacuum (lo-' mb) in special containers, which permit their rotation. The crystallographic quality of the samples was checked by X-ray diffraction after the experiments. The angles were determined within a t2' precision. The beam line EXAFS I 1 was equipped with a harmonics rejection device made of two parallel mirrors [2]. This was particularly important to avoid thickness effects [3]. Polarization of the incident beam is estimated to be about 90% (we verify that its exact value does not affect the conclusions). Figure 1 presents angular dependence of alkali XANES spectra of first stage K and Rb compounds. After a simple pre-edge background substraction, the curves are normalized with respect to the thickness of the sample i.e. multiplied by cos 8 to take into account the apparent thickness at non-zero angle. Energy lev1 Fig. 1 : Thickness normalized K-edge XANES spectra for several orientations.
Bitterness reduction in grapefruit juice through active packaging

Naringin and limonin are the principle bitterness components of citrus juices. Our objective was to determine if the perceived bitterness in grapefruit juice could be reduced during storage through interaction with active packaging film. Storage of 10° Brix grapefruit juice at 7°C in contact with fungal-derived naringinase immobilized on cellulose acetate film reduced bitterness as perceived by a sensory panel. The films reduced naringin and limonin concentration by hydrolysis and adsorption respectively. Reduction in the naringin and limonin content of grapefruit juice by cellulose acetate films containing immobilized enzyme from 600–400 mg/l and 8.0–6.7 mg/l respectively could be detected as a reduction in bitterness by a sensory panel (p < 0.10). As the area of film (cm2)/volume of juice (ml) ratio increased from 1.1 to 3.6, the time to decrease the naringin level decreased. The reduction in naringin was not affected by agitation or holding the samples quiescently. The amount of enzyme desorbed from the film represented only 2% of the amount of enzyme immobilized in the film. The reduction in bitterness comes from direct interaction with the active packaging films. © 1998 John Wiley & Sons, Ltd.
A semiclassical description of protonium formation in antiproton collisions with molecular hydrogen

In a departure from our previous work modeling antiproton capture on Helium, with it's relatively straightforward, fixed center target, extending the semiclassical approach to molecular hydrogen, i.e. a multi-center target with target masses identical to the projectile, requires that we revisit the fundamental nature of our model, including the momentum-dependent Heisenberg core used to stabilize electrons in the ground state. Happily, with minor modifications of the model parameters, it seems up to this new task. Here we discuss the main features of this revised model of a semiclassical molecular target, and use it to examine antiproton collisions with H2; details of the collision process are presented, including the energy and angular momentum states of incident antiprotons which result in formation of pp-, and the resulting distribution of protonium atomic states.
The Use of Bracing Dampers in Steel Buildings under Seismic Loading

This study focuses on the modeling of manufactured damper when used in steel buildings. The main aim of the manufactured dampers is to protect the steel buildings from the damaging effects that may result due to earthquakes by introducing an extra damping in addition to the traditional damping.Only Pure Manufactured Dampers, has been considered in this study. Viscous modeling of damping is generally preferred in structural engineering as it leads to a linear model then it has been used during this study to simulate the behavior of the Pure Manufactured Damper. After definition of structural parameters of a manufactured damper (its stiffness and its damping) it can be used as a structural element that can be added to a mathematical model of the structure. As the damping of manufactured dampers is generally greater than the damping of traditional materials, then the resulting damping matrix for the whole structure will be classified as a nonclassical damping. As most of literature on earthquake engineering have been written in terms of terminology related to mode superposition method and as this method is applicable to classical damping only. Then, this study tried to check the accuracy of the mode superposition method when applied to a structure with manufactured dampers. In this checking, approximated results of mode superposition method have been compared with more accurate results of direct integration method. From this comparison, it has been noted that the mode superposition method has different levels of accuracy depending on the relation between the fundamental frequency of the structure and the dominate frequency of the earthmotion. If the frequency of the structure is approaching to a dominate frequency of the earthmotion, then the damping effect will be important and the difference between the direct integration method and the model superposition method is increasing and vice versa
Advantageous heterogeneously catalysed hydrogenation of carvone with supercritical carbon dioxide

The hydrogenation of carvone was investigated for the first time in high-density carbon dioxide. The hydrogenation over 0.5 wt% Pd, or Rh, or Ru supported on alumina was found to be generally faster in a single supercritical (sc) phase (fluid reagents) than in a biphasic system (liquid + fluid reactants). The reaction with Pd produced fully hydrogenated products (isomers of carvomenthone) and carvacrol. The Rh catalyst was more selective and favoured carvomenthone isomers with higher selectivity and carvotanacetone as a secondary product. Additionally, the rhodium catalysed reaction exhibited high > 84% selectivity of carvotanacetone with the conversion of > 25% after only 2 min of reaction. The less active Ru catalyst gave significantly lower conversion and the product variety was greater as carvomenthone isomers, carvotanacetone and carvacrol were formed. The conversion and selectivity to carvomenthone within 2 h of the reaction starting followed the order: Pd > Rh > Ru and Rh > Pd > Ru, respectively. High conversion, and diverse and high selectivity accompanied by significant reduction in reaction time depending on the catalyst were achieved in supercritical CO2 compared with hydrogenation occurring in conventional organic solvents.
Effect of Pressure, Temperature, Modifier, Modifier Concentration, and Sample Matrix on the Supercritical Fluid Extraction Efficiency of Different Phenolic Compounds

The effects of different parameters such as pressure, temperature, modifier identity, modifier volume, and sample matrix on the supercritical fluid extraction of several phenolic compounds are investigated. The results show that at a constant temperature, elevating the pressure from 100 to 300 atm increases the efficiency of extraction of compounds from topsoil and sand, but it does not have any effect on the extraction of the same compounds from carbon black. Increasing the temperature from 40 to 80°C (at a constant pressure of 100 atm) reduces the extraction efficiency of the components by more than 50%. However, the extraction efficiency increases by more than 20% by keeping the density of supercritical CO 2 constant (0.63 g/mL) and raising the temperature. Using different modifiers (e.g., methanol, acetonitrile, acetone, water, and dichloromethane) for the extraction of phenolic compounds from topsoil at low pressure (100 atm) and temperature (40°C) shows that methanol is more effective than other types of modifiers used in this study. In addition, the results demonstrate that the interaction of the target analytes with the sample matrix could have a major effect on extraction efficiency. Even when using extreme conditions (e.g., addition of 200 μL methanol as a modifier onto the matrix during static extraction at 300 atm and 80°C), it was not possible to extract phenolic compounds from carbon black.
Freezing and melting of azeotropic mixtures confined in nanopores: experiment and molecular simulation

The paper reports on a qualitative comparison between experimental measurements and molecular simulations of the freezing and melting of azeotropic mixtures confined in nanoporous materials. Dielectric relaxation spectroscopy was used to determine the experimental solid/liquid phase diagram of CCl4/C6H12 mixtures confined in activated carbon fibres. Grand Canonical Monte Carlo simulations combined with the parallel tempering technique were used to model the freezing of the azeotropic Lennard–Jones mixture Ar/CH4 in a graphite slit pore. The structure of the crystal phase in the simulations is investigated by means of positional and bond-orientational pair correlation functions and appropriate bond-order parameters. Both simulations and experiments show that the phase diagram of the confined mixture is of the same type as that for the bulk, but the solid/liquid coexistence lines are located at higher temperatures. The effect of confinement and of the wall/fluid interaction on the location of the azeotrope is discussed.
Electronic Structure and Doping Behavior of PANI-NSA Nanofibers Investigated by Resonance Raman Spectroscopy

Polyaniline nanofibers (from 93 to 220 nm) doped with β-naphtalenesulfonic acid (PANI-NSA) have been characterized. Nonhomogeneity in the thickness of fibers, as can be seen with scanning electron microscopy, is the reason for their instability under the HCl doping process. Resonance Raman spectral profiles of PANI-NSA fibers suggest a lower protonation state than the emeraldine salt forms. Observation of Raman bands, which are a result of cross-linking, confirms that one of the properties of the polymeric structure formed in micellar polymerization is the type of connection between chains.
Hydrothermal synthesis of highly porous carbon monoliths from carbohydrates and phloroglucinol

A new sustainable approach for the synthesis of highly porous carbon cryogels and aerogels is presented. Such monolithic carbogels have been obtained via the hydrothermal gelation of a phenolic compound, i.e. phloroglucinol, with monosaccharides, i.e. glucose, fructose or xylose. While the carbon precursors used herein can be isolated from lignocellulosic biomass, the hydrothermal carbonization process does not involve any catalyst, making our current approach meet green chemistry principles. Beyond an understanding of the gelation process, the influence of the drying method and synthetic pathways on the final textural properties has been underlined. Because of surprisingly high micro-mesopore surface areas and volumes, up to 1159 m2 g−1 and 1.5 cm3 g−1 respectively, together with airy interlinked macromorphologies, these sugar-derived dried-gels appear as really promising candidates for separation and heterogeneous catalysis. Furthermore, after further thermal treatment under inert atmosphere, conductive carbogels depicting significant specific surface areas and volumes, up to 700 m2 g−1 and 0.9 cm3 g−1, together with a preserved monolithic morphology can be obtained. Thus, these new biomass-derived carbogels are expected to offer a broad range of potential applications, such as electrodes for batteries and fuel cells, or scaffolds for hydrogen and carbon dioxide storage.
Expeditious, Metal‐Free, Domino, Regioselective Synthesis of Highly Substituted 2‐Carbonyl‐ and 2‐Phosphorylfurans by Formal [3+2] Cycloaddition

2-Functionalized furans are very easily synthesized by exploiting the dual nucleophilic character of 1,2-dicarbonyls and the dual electrophilic properties of (2-chloro-2-nitroethenyl)benzenes in a one-pot, formal [3+2] cycloaddition. Using a base (DBU), the desired trisubstituted heterocycles were formed rapidly (10–30 min) in good to excellent yields (51–92 %), and this versatile, metal-free methodology was applied to the synthesis of 2-acyl- and 2-carboalkoxyfurans and furan-2-carboxamides. Additionally, by using 2-ketophosphonate derivatives as dinucleophiles, the corresponding 2-phosphorylfurans were formed in good yields (53–74 %).
A Convenient Method for the Preparation of Alkanolamides.

Long chain alkanolamides have attracted considerable interest because of their intrinsic amphiphilic properties. They are frequently used as a surfactant for cosmetics and pharmaceutical use. In the course of the synthesis of alkanolamides, control of chemoselective amide formation over competing O-acylation of neighboring hydroxyl groups plays a key step. Several methods have been developed which include a few enzymatic synthesis and the reaction of carboxylic acid with amino alcohols by the aid of N-ethoxy1-ethoxy-dihydroquinone (EEDQ) in ethanol reflux condition. However, these known methods have drawbacks for example narrow application scope in enzymatic reaction, longer reaction time and harsh reaction condition. Recently, we have reported that chemoselective N-acylation of amino alcohols promoted by magnesium oxide in aqueous organic solution. Although the use of this method was successful in many cases, preparation of acid chloride is not always easy so there is still a strong need for more convenient amidation method of amino alcohols. Now we report a useful procedure for the efficient and chemoselective amidation of hydrophilic amino alcohols with mixed anhydride generated from carboxylic acid and ethylchloroformate (Scheme 1). Treatment of benzoic acid 1a with ethylchloroformate (1.1 equiv) in the presence of N-methylmorpholine (1.1 equiv) in THF gave mixed anhydride, which subsequently reacted with tris(hydroxymethyl)aminomethane 3a in DMF and TEA (1.1 equiv) to give alkanolamide 4a in 85% yield (entry 1 in Table 1). The formation of by-products such as O-acylated and N, O-diacylated derivatives have not been observed in HPLC analysis. After the disappearance of mixed anhydride checked by TLC analysis, DMF was evaporated in vacuo. The residue of reaction mixture was extracted with ethyl acetate, washed with water. The organic layer was analyzed by HPLC. As shown in Figure 1, small amount of benzoic acid were detected without by-products. Benzoic acid was easily separated by flash chromatography. As an additive for the synthesis of mixed anhydride, TEA as well as N-methylmorpholine was effective. Of solvents tested, THF and ether were suitable. Using aliphatic carboxylic acid 2b, alkanolamide 4b was also obtained in high yield (entry 2). Further, this method was successfully extended to other acids containing acid or base-sensitive groups such as cyclic disulfide, ester and acetate (entry 3, 4 and 5). In all cases, byproducts that are usually formed in the reaction of acid chlorides with amino alcohols were not detected. Preferential amine selectivity can be explained by assuming low electrophilicity of mixed anhydride comparing with acid chloride. Because of its low electrophilicity, more nucleophilic amino groups may only react with mixed anhydride. The reaction also worked well for the other hydrophilic amine such as ethanolamine, DL-serine methyl ester and diethanolamine. The desired alkanolamides 4f, 4g and 4h
ON THE CDS/CUINSE2 CONDUCTION-BAND DISCONTINUITY.

Recent calculations of the electron affinity difference between CdS and CuInSe2 indicate that the conduction band (CB) minimum of CuInSe2 is below the CB minimum of CdS. As a consequence, a spike occurs in the CB at the CdS/CuInSe2 interface. Such a spike is commonly considered as in conflict with good photovoltaic performance of heterojunction solar cells. It is outlined here that the simple assumption of thermionic emission across the junction can explain an unimpeded electron transport in the case of an n+p structure (n‐type window, p‐type absorber), even when a spike in the CB occurs.
A correlated basis set for nonadiabatic energy calculations on diatomic molecules

A new explicitly correlated basis set suitable for nonadiabatic energy calculation on small diatomic molecules is presented. The basis functions consist of correlated Gaussians multiplied by powers of the internuclear distance. N-body formulas for Hamiltonian matrix elements and energy gradient components are derived and presented along with a discussion of the nonadiabatic Hamiltonian and symmetry considerations. A sample calculation is presented for the ground state energy of the benchmark system H2+ in which rapid convergence to near exact results was observed.
Fluorescent photochromes of diarylethene series: synthesis and properties

The research data in the field of fluorescent photochromic di(het)arylethenes published over the last decade are summarized. The characteristics of these compounds significant for their application in the design of molecular optical memory systems and photocontrolled switches are considered. The main types of diarylethenes and methods for their synthesis are described, and the correlations between structure and spectral properties, in particular, fluorescence characteristics are analyzed. Considerable attention is given to the means for endowing diarylethenes with fluorescence properties as one of the most promising methods for data readout from molecular information carriers. The bibliography includes 203 references.