Miracle-dz/UniFAR-FTUs huggingface dataset:
Synthesis and Synthetic Potential of Acylsilanes

Presentation des differentes methodes de synthese des acylsilanes, de leur reactivite. Ce sont des reactifs de synthese potentiellement interessants par exemple pour l'acylation nucleophile. Plusieurs applications sont presentees dont la preparation de plusieurs pheromones et d'une sila-vitamine A
Strain-Tunable Spin Moment in Ni-Doped Graphene

Graphene, due to its exceptional properties, is a promising material for nanotechnology applications. In this context, the ability to tune the properties of graphene-based materials and devices with the incorporation of defects and impurities can be of extraordinary importance. Here we investigate the effect of uniaxial tensile strain on the electronic and magnetic properties of graphene doped with substitutional Ni impurities (Ni_sub). We have found that, although Ni_sub defects are non-magnetic in the relaxed layer, uniaxial strain induces a spin moment in the system. The spin moment increases with the applied strain up to values of 0.3-0.4 \mu_B per Ni_sub, until a critical strain of ~6.5% is reached. At this point, a sharp transition to a high-spin state (~1.9 \mu_B) is observed. This magnetoelastic effect could be utilized to design strain-tunable spin devices based on Ni-doped graphene.
Complexes of platinum and palladium with 4-nitrobenzoic hydrazide: synthesis and cytotoxic activity

AbstractNew complexes of platinum and palladium were isolated with 4-nitrobenzoic hydrazide (4-NH) and characterized by spectroscopic techniques. Results show that the ligand is coordinated to metallic ions by the basic nitrogen of NH2 group and have the general structure cis-[M(4-NH)2X2] where M= Pt or Pd and x = Cl or I. The compound III, [Pt(4-NH)2I2], was found to display cytotoxicity (IC50 = 0.96 µmol L−1) against the K562 tumoral cell line. This complex is significantly more cytotoxic than cisplatin.
Calculation of Equilibrium Constants for Isotopic Exchange Reactions

It is pointed out that the possibility of chemical separation of isotopes is a quantum effect. This permits a direct calculation of the difference in the free energies of two isotopic molecules. Tables and approximation methods are given which permit a rapid calculation of equilibrium constants if the frequency shifts on isotopic substitution are known. Several applications are discussed.
Reorientational motions of hydrogenic species in 12-tungstophosphoric acid 14-hydrate: a neutron scattering study

Variable-temperature incoherent quasielectric neutron scattering (QENS) measurements have been used to investigate motions of hydrogenic species in 12-tungstophosphoric acid 14-hydrate (H3PW12O40·14H2O). Reorientational motions are classifiable as those of H2O (free and coordinated to hydrated protons) and H3O+[free and in non-centrosymmetric H+(H2O)n units]. Scattering spectra are satisfactorily modelled assuming quasielastic broadening to arise from a three-fold reorientation of H3O+ about an ionic C3 axis with a (model independent)Ea= 19 ± 1 kJ mol–1. Slower reorientation of H2O and H self-diffusion would not give discernible broadenings on the instrument used.
Self-limiting oxidation of copper

The classical theory of Cabrera–Mott describes passivation film formation on metals, where they predicted that this film grows as a uniform layer due to a field-enhanced ionic transport mechanism. Here we present experimental evidence, based on in situ transmission electron microscopy of copper oxidation, that the passivation film nucleates and grows as oxide islands, not as a uniform layer. We propose an alternative phenomenological theory to describe passivation film formation, based on island growth followed by coalescence.
Applications of Raman Spectroscopy in Dentistry: Analysis of Tooth Structure

Abstract: Tooth enamel is the most mineralized tissue in the human body, and in this article the use of Raman spectroscopy for the analysis of tooth structure, a comparison with synthetic apatites, and use in dentistry are described. Spectral peaks that are related to dental hard and soft tissues are discussed, which provide crucial data in understanding the chemical structural properties of dentin and enamel. The Raman spectrum of dentin confirms the presence of crystalline phosphate-based minerals in dentin. Both dentin and enamel consist of two primary components: an inorganic or mineral phase that closely resembles hydroxyapatite and the Raman spectrum of dentin that confirms the presence of crystalline phosphate-based minerals in dentin. Hence, the mineral phase in dentin and enamel may be characterized essentially as nonstoichiometric substituted apatite. The presence of carbonate (A and B type) incorporated in the hydroxyapatite lattice is also confirmed by the presence of spectral bands. The organic phase, which is mainly composed of type I collagen, is confirmed by the spectral bands of amide I and amide II bands, tryptophan, and phenylalanine. Furthermore, these spectral bands associated with organic and inorganic parts of the enamel and dentin are useful in predicting early formation of carries formation.
Noncatalytic chemical vapor deposition of graphene on high-temperature substrates for transparent electrodes

A noncatalytic chemical vapor deposition mechanism is proposed, where high precursor concentration, long deposition time, high temperature, and flat substrate are needed to grow large-area nanocrystalline graphene using hydrocarbon pyrolysis. The graphene is scalable, uniform, and with controlled thickness. It can be deposited on virtually any nonmetallic substrate that withstands similar to 1000 degrees C. For typical examples, graphene grown directly on quartz and sapphire shows transmittance and conductivity similar to exfoliated or metal-catalyzed graphene, as evidenced by transmission spectroscopy and transport measurements. Raman spectroscopy confirms the sp(2)-C structure. The model and results demonstrate a promising transfer-free technique for transparent electrode production.
Development of Hybrid Membranes Using Chitosan and Silica Precursors for Pervaporation Separation of Water + Isopropanol Mixtures

Using a sol−gel technique, organic−inorganic hybrid membranes were prepared using chitosan and mixed silica precursors such as tetraethoxysilane and γ-glycidoxypropyltrimethoxysilane. The γ-glycidoxypropyltrimethoxysilane acted as a coupling agent to enhance the compatibility between the organic (chitosan) and the inorganic (tetraethoxysilane) phase. Different techniques such as Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) were employed to study the physicochemical changes in the resulting membranes. These membranes were tested for their ability to separate water + isopropanol mixtures by pervaporation in the temperature range of (303 to 323) K. The experimental data demonstrated that both flux and selectivity were increased simultaneously with increasing the amount of γ-glycidoxypropyltrimethoxysilane. However, this trend no longer remained when the content of γ-glycidoxypropyltrimethoxysilane.
Anticlastogenic, antitoxic and sorption effects of humic substances on the mutagen maleic hydrazide tested in leguminous plants

The potential anticlastogenic and antitoxic effects of a soil humic acid (HA), a peat HA and a peat fulvic acid (FA) on the mutagen maleic hydrazide (MH) have been investigated in two legume species, Vicia faba and Pisum sativum. Both HAs and FA were tested at two different concentrations, 20 and 200 mg l−1, either alone or after 24‐hour interaction with 10 mg l−1 of MH before addition to the legume seeds. Anticlastogenicity, i.e. an antimutagenic action defined as the capacity for minimizing chromosome breakages, was evaluated by counting both micronuclei (MN) and aberrant anatelophases (AAT) in root‐tip cells. Length and dry weight of the seedling primary root were measured to test the antitoxic activity of HA and FA on MH. The possible occurrence and extent of adsorption or desorption of MH onto or from HA were also investigated. The two species responded differently to the anticlastogenic tests, with V. faba showing a greater number of MN and AAT anomalies than P. sativum. Peat HA and FA exhibited anticlastogenic and antitoxic activities of similar intensity and greater than those of soil HA. The adsorption capacity of both HAs for MH was small, thus suggesting that adsorption is not a major mechanism responsible for the reduction of clastogenicity and antitoxicity of MH by HA.
Analysis of Some Natural Antioxidants by Thin‐Layer Chromatography and High Performance Thin‐Layer Chromatography

Abstract (HP)TLC is a technique with large applicability in the fields of plant material analysis and stability tests of extracts and finished products. The implementation of a modern standardized methodology led to the increasing of acceptance and recognition of (HP)TLC as competitive analytical method. (HP)TLC has many advantages, such as lower costs, short time analysis, the possibility of multiple detection, and specific derivatization on the same plate, etc. The natural antioxidants (polyphenols) are present in plant extracts; they play a key role in antioxidative defence mechanisms in biological systems and they act as free radicals scavenging agents. The separation of polyphenols from each other and from other components of the plant extracts can be done by a great number of (HP)TLC developed techniques. Mostly, complex crude plant extracts are screened for antioxidant activity or to distinguish the components of plant extracts with antioxidant character or radical‐scavenging properties. (HP)TLC has been used for the determination of individual antioxidant capacity of target compounds and it might be of interest to the routine chemical or biological screening and they can solve real analytical problems.
Addiction and suicide

After a survey of the particularly great risk of suicide among alcoholics and drug addicts, the psychopathologically common base of suicidal tendencies and addiction which arise from the advances of the theory of narcism are presented. Comparative clinical investigations in two groups of patients who had attempted suicide (with and without alcoholism) show that every 4th suicidal patient has alcohol problems. Alcoholic patients present a more pathological self-rating, they relatively frequently live alone in poor accommodation and even considerably worse social and economic conditions. Language: de
Variation in extraction of calcium from dry-ashed embryos of Cucurbits and other lipid-rich seeds

Abstract All cucurbit embryos analyzed showed a decrease in the ease with which calcium could be extracted from the ash as the ashing temperature increased beyond 600°C. After ashing at 500°C, the Ca in the cucurbit ash was fully extracted by 5% o HC1. After 650°C ashing, lower than expected Ca levels were obtained unless additional ash treatment with HNO3 and HC1 was applied. Castor bean embryos plus endosperm showed the same effect but other oily embryos tested did not need ash treatment to fully extract Ca from either the 500 or 650°C ash. Neutron activation analysis indicated that the differences in ash characteristics were related to the differences in concentrations of K and P in the embryo tissues.
220 MHz spectra of heparin, chondroitins, and other mucopolysaccharides

Characteristics of proton magnetic resonance spectra of heparins at 220 MHz, coupled with spectral data for model compounds and with information obtained chemically, indicate that heparins are composed principally of (1 → 4)-linked α-L-idopyranosyluronic acid residues (3) and 2-amino-2-deoxy-α-D-glucopyranosyl residues (1); also, that sulfate groups are located at position -2 and -6 of 1, and -2 of 3. D-Glucopyranosyluronic acid residues (2) appear to be minor constituents, which is at variance with all structures that have been proposed previously for heparin.Spectra of chondroitins A, B, and C, which are readily distinguishable, are in close accord with formulae that have been proposed for these mucopolysaccharides; on the same basis, the spectrum of keratan sulfate is less consistent. Hyaluronic acid affords a poorly resolved though, nonetheless, distinctive spectrum. The general view that mucopolysaccharides are constituted basically of residues of hexosamine and uronic acid in equimolar proportion re.
Comparison of disilane and hydrogen adsorption on Si(111)‐7×7

Multiple internal reflection (MIR) infrared spectroscopy has been used to study the adsorption of H and Si2H6 on the Si(111)‐7×7 surface at 200 and 400 K. Both adsorbates react with the Si(111)‐7×7 surface to yield a variety of silicon hydrides with similar temperature dependence. Adsorption of atomic hydrogen at 400 K produces three different monohydrides with characteristic vibrational frequencies of 2076, 2086, and 2095 cm−1. At 200 K hydrogen adsorption produces a surface dihydride with a stretching frequency of 2119 cm−1 and a trihydride with a stretch frequency of 2143 cm−1 in addition to the three surface monohydrides. Adsorption of Si2H6 on Si(111)‐7×7 at 400 K yields a single absorption feature centered at 2096 cm−1 attributed to surface SiH species. The broad featureless spectrum is indicative of surface disorder due to the deposition of additional surface silicon atoms from the adsorbed disilane. At 200 K the adsorption of Si2H6 yields a sharp vibrational feature at 2154 cm−1 over a broad backg.
Comparative erosion–corrosion and electrochemical studies of Ni austenitic cast iron in acidic slurry medium

Laboratory experiments were conducted on the erosion–corrosion resistance of four groups of austenitic cast iron with different nickel contents under different acidic slurry conditions. The experiments involved measuring weight loss, examining corrosion morphology as well as X-ray diffraction analysis and electrochemical techniques. While the results showed little erosion–corrosion in a base sand particles environment, erosion–corrosion increased progressively with additions of HCl solution. With the presence of H+, intergranular corrosion and pitting attacks were centred at the boundaries of graphite flakes and alloy carbides. The electrochemical tests showed that the enrichment of nickel and copper in low Ni austenite cast iron can increase the corrosion potential to some extent. As a result, the low Ni cast iron in which Ni content is 8·36 wt-%, and Mn content is 6·57 wt-% exhibited better corrosion resistance than other low Ni cast irons and demonstrated comparable performance with high Ni austenite cast iron.
The Crystal Structure of 4,6-Di-O-Benzyl-2,3-Dideoxy-2,2,3,3-Tetrafluorogalactose

The crystal structure of a reducing dibenzylated tetrafluorinated galactose derivative is reported. The compound crystallized as the α-anomer, and a single OH···O hydrogen bond dominates the crystal packing, leading to a helical arrangement containing two galactose derivatives per turn. Interestingly, the helices are cross-linked by ArC–H···F contacts, but without significant Ar–Ar interactions.
Capillary Hysteresis in Nanopores: Theoretical and Experimental Studies of Nitrogen Adsorption on MCM-41

Capillary hysteresis in cylindrical nanopores has been studied using MCM-41 as the prime example of a mesoporous material. These materials, due to their regular pore structure, can be considered to be candidates for reference adsorbents for standardizing adsorption measurements and methods for characterization of porous solids. They provide a unique opportunity for verification of theoretical models employed for predicting phase equilibrium in confined geometry. Three samples with monodisperse pore channels have been synthesized and examined using X-ray diffraction (XRD). Nitrogen adsorption isotherms were modeled using nonlocal density functional theory (NLDFT) in a wide range of pore sizes (18-80 A). Theoretical isotherms for pore channels with sizes corresponding to those identified by XRD were compared with experimental isotherms at different temperatures between 70 and 82 K. The latter have been measured independently on two different adsorption setups. The theoretical thermal dependence ofthe thermodynamic adsorption-desorption hysteresis predicted by NLDFT is confirmed by the experimental measurements. It is shown that at 77.4 K NLDFT quantitatively predicts equilibrium phase transitions in cylindrical channels of MCM-41. Theoretical and experimental results prove that the nitrogen hysteresis observed at temperatures below 77.4 K is associated with metastability of the adsorption branch of the isotherm. The absence of experimental hysteresis on samples with pore size of about 40 A at temperatures above 77.4 K cannot be explained by the capillary critical temperature for a given pore size being achieved as was assumed previously.
International Journal of Food Engineering Effect of the NaOH Concentration and Temperature on the Dissolution Mechanisms of ß-Lactoglobulin Gels in Alkali

The dissolution mechanisms of model protein gels (made from a single protein, ßlactoglobulin) in alkali were studied at different NaOH concentrations and temperatures. A recent study has shown that the free volume within the swollen gel is a key parameter that determines the dissolution rate (Food Hydrocolloids (2007) 21:1275). This suggests that proteins ‘diffuse’ in the swollen gel next to the solution before they are dissolved. We extend this hypothesis here by showing that only small oligomers (trimers and smaller), such as those formed after the cleavage of large aggregates, are likely to diffuse throughout the gel. Large aggregates (> 200 kDa) are considered to disentangle at the gel/solvent interface. Size exclusion chromatography has been used to determine the size distributions of the aggregates released from the gel matrix, and to follow the breakdown kinetics of soluble aggregates in alkaline conditions. Analysis of the dissolution process at different temperatures reveals that at low NaOH concentrations (< 0.1 M), the breakdown of large aggregates in alkali exhibits a temperature dependency different from that of the overall dissolution process. At high NaOH concentrations (> 0.3 M), where swelling is inhibited, the increase in the dissolution rate seems to be related to the destruction of cross-linked aggregates, in particular via the beta-elimination of intermolecular disulfide bonds. A previously unobserved type of dissolution behavior at 0.87 M NaOH and at high temperatures is reported.
胰岛素增敏剂一Thiazolidinediones研究现状

Thiazolidinediones(TDs)是一类新型的胰岛素抵抗治疗药物。 动物及临床实验证实TDs通过激活核受体过氧化物酶体增殖物激活受体-γ(PPAR-γ)显著增加胰岛素敏感性，改善胰岛β-细胞功能，降低血糖和胰岛素水平，缓解高血压及脂代谢紊乱，对2型糖尿病大血管和微血管病变亦具有保护作用。 临床使用耐受性好，低血糖发生率低。 但其中的Troglitazone具有明显的肝脏毒性。
Titanium trisulphide (TiS3) nanoribbons for easy hydrogen photogeneration under visible light

First evidence of hydrogen evolution by using titanium trisulphide (TiS3) as a photoanode in a photoelectrochemical cell (PEC) is reported. Synthesized TiS3, composed of numerous nanoribbons, has been structurally, morphologically and photoelectrochemically characterized. Moreover, the value of its flat band potential has been estimated (Vfb = −0.68 ± 0.05 V vs. Ag/AgCl) by Electrochemical Impedance Spectroscopy (EIS) measurements. This value has been used to depict the band energy levels of the TiS3/electrolyte interface. Finally, flows of photogenerated hydrogen up to 1.80 ± 0.05 μmol H2 min−1 have been quantified by Mass Spectrometry (MS) at a (Ag/AgCl) bias potential of 0.3 V, yielding a photoconversion efficiency of about 7%.
Product rotational polarization in photon‐initiated bimolecular reactions

This paper concerns the semiclassical description, calculation and measurement of angular momentum polarization in the products of elementary gas‐phase bimolecular reactions. A unified, semiclassical treatment of the centre‐of‐mass correlated (k,k′,j′) angular distribution involving the reagent and product relative velocity and the product angular momentum vectors is described, and is related to other methodologies already existing in the literature. Explicit expressions are provided enabling experimentalists to extract rotational polarization information from crossed‐molecular beam and photon‐initiated reaction studies, under a variety of experimental conditions. Furthermore, the strategy developed is well suited to the theoretical calculation of reaction product polarization, in particular, using classical trajectory methods. An illustrative example of such a calculation is presented, and the centre‐of‐mass polarization data provided is used to simulate the laboratory frame rotational moments that can b.
Volatile Constituents of Nepeta heliotropifolia Lam., Mentha mozaffarianii Jamzad and Ziziphora persica Bunge. Three Labiatae Herbs Growing Wild in Iran

Abstract The composition of the essential oils from three Labiatae species from Iran—Nepeta heliotropifolia Lam. and Mentha mozaffariani Jamzad, which are endemic to Iran, and Ziziphora persica Bunge. —were obtained by hydro-distillation and analyzed by GC and GC/MS. 1,8-Cineole (16.8%), 4aα,7α,7aβ nepetalactone (16.3%), cis-sabinene hydrate (16.1%) and linalool (11.9%) were the main components among the 23 constituents characterized in the oil of Nepeta heliotropifolia, representing 92.8% of the total components detected. Twenty compounds were identified in the oil of M. mozaffarianii, representing 83.6% of the total oil, with 1,8-cineole (53.5%) being the major constituent. The oil of Z. persica was characterized by high amount of pulegone (27.8%), neomenthol (22.5%) and p-menth-3-en-8-ol (18.1%) among the 34 components, comprising 94.7% of the total oil detected. All three oils were richer in oxygenated monoterpenes than sesquiterpenes.