Miracle-dz/UniFAR-FTUs huggingface dataset:
Sol-Gel Synthesis of Monolithic Molybdenum Oxide Aerogels and Xerogels

Monolithic molybdenum trioxide aerogels and xerogels have been synthesized by the sol–gel method. A three-dimensional molybdenum oxide network is achieved by suppressing MoO bond formation through a ligand exchange process. IR spectroscopy is used to characterize the bond formations during gelation, aging, and drying of the gels. The as-prepared aerogels are low density (0.15–0.30 g cm–3) amorphous materials with surface areas of 150–180 m2 g–1 . Upon heating to 400 °C, the amorphous solids crystallize to orthorhombic MoO3 .
The Crystal and Molecular Structure of the Hydrated Light Lanthanoid(III) Chloroacetates, [{M(ClCH2CO2)3}3(H2O)5]n, (M=La, Pr, Nd, and Eu)

The crystal and molecular structures of the hydrated lanthanum(III), neodymium(III), and europium(III) chloroacetates indicated in the title were determined by the single-crystal X-ray diffraction method; these three salts as well as the praseodymium(III) salt are apparently isomorphous. By the same synthetic technique, gadolinium(III) or heavier lanthanoid(III) did not give the isomorphous salts. Their crystals are monoclinic with the space group of P21⁄c, and the cell constants of the neodymium(III) salt, for example, are, a=14.805(4), b=18.765(4), c=14.403(5) A, β=95.13(3)°. There are crystallographically independent three kinds of nine-coordinated metal atoms: Nd(1), Nd(2), and Nd(3). Among them, Nd(1) and Nd(2) are best approximated as being in a tricapped trigonal prism geometry. The Nd(3) is best regarded as being in a monocapped square-antiprism geometry, although one more additional oxygen atom, O(35), approaches one side face. In the lanthanum(III) complex, O(35) is thought to be ligated to La(3.
Metallization-induced damage in III–V semiconductors

Damage introduced from sputtering deposition, electron-beam evaporation, and thermal evaporation were investigated with an InGaAs/GaAs strained quantum well structure. This strained quantum well structure was found to be a more sensitive probe of damage, revealing metallization-induced damage where none was found using comparable lattice-matched quantum wells. The damage was found to vary with deposition method, deposition rates, or even different metal sources used. Noticeable degradation of the photoluminescence of the strained quantum well was observed after a thin layer (∼100 A) of metal was deposited.
The 57Fe nuclear magnetic resonance shielding in ferrocene revisited. A density-functional study of orbital energies, shielding mechanisms, and the influence of the exchange-correlation functional

The 57Fe nuclear magnetic resonance (NMR) shielding and chemical shift in ferrocene, Fe(C5H5)2, are studied using density functional theory (DFT) and gauge-including atomic orbitals (GIAO). Electronic factors contributing to the chemical shift are discussed in detail. It is shown that the chemical shift is entirely determined by paramagnetic contributions which in turn are dominated by metal based occupied-virtual d→d couplings. In particular, the HOMO-1(a1′) and the HOMO (e2′) couple with the LUMO (e1″). It is argued that the 57Fe nucleus in ferrocene is less shielded than in the reference compound (iron pentacarbonyl) due to a smaller HOMO-LUMO gap, resulting in stronger interactions between occupied and virtual orbitals. The influence of the XC functional on the calculated molecular orbital (MO) energies of frontier orbitals is discussed. Different generalized gradient approximations (GGA) give similar results whereas hybrid functionals that incorporate part of the Hartree–Fock exchange stabilize occup.
Palladium/Phosphite or Phosphate Catalyzed Oxidative Coupling of Arylboronic Acids with Alkynes to Produce 1,4‐Diaryl‐1,3‐butadienes

The intermolecular oxidative coupling of arylboronic acids with internal alkynes efficiently proceeds in a 2:2 manner in the presence of palladium acetate, a triaryl phosphite or phosphate, and silver carbonate as catalyst, ligand, and oxidant, respectively, to produce the corresponding 1,4-diaryl-1,3-butadiene derivatives.
Lifetimes of intermediates in the β-sheet to α-helix transition of β-lactoglobulin by using a diffusional IR mixer

The extremely slow α-helix/β-sheet transition of proteins is a crucial step in amylogenic diseases and represents an internal rearrangement of local contacts in an already folded protein. These internal structural rearrangements within an already folded protein are a critical aspect of biological action and are a product of conformational flow along unknown metastable local minima of the energy landscape of the compact protein. We use a diffusional IR mixer with time-resolved Fourier transform IR spectroscopy capable of 400-μs time resolution to show that the trifluoroethanol driven β-sheet to α-helix transition of β-lactoglobulin proceeds via a compact β-sheet intermediate with a lifetime of 7 ms, small compared with the overall folding time of β-lactoglobulin.
Research progress on the preparation and application of monodisperse cationic polymer latex particles

This review is focused on the features, preparation and applications of uniform cationic polymer latex particles, as well as on the formation mechanism of uniform latex particles. Substantial progress in the size and shape control of polymer latex particles has been made using several methods such as dispersion polymerization, conventional emulsion polymerization, surfactant-free emulsion polymerization and seeded emulsion polymerization. Uniform cationic polymer latex particles have wide applications such as drug carriers, diagnostics, templates and additives. However, two major problems are the inhomogeneous size and low surface charge density, which limit further functionalization and the application of cationic polymer latex particles. Finally, the future trends and perspectives are described. Copyright © 2012 Society of Chemical Industry
The concentrations of beta-carotene, vitamin A and vitamin E in bovine milk in regard to the feeding season and the share of concentrate in the feed ration

The objective of the present study was to determine the β-carotene, vitamin A and vitamin E content of cow’s milk in regard to the selected nutritional factors and the stage of lactation. The experimental materials consisted of milk samples from 90 Holstein-Friesian cows fed a partly mixed ration (PMR – maize silage, grass silage and concentrated feed). The contents of vitamin A, vitamin E and β-carotene in milk were determined primarily by the feeding season. A gradual decrease in vitamin concentrations in milk fat was observed during winter feeding. The inclusion of pasture sward into the feed ration for dairy cows caused an increase (P≤0.01) in the concentrations of vitamin A, vitamin E and β-carotene in milk. A higher concentrate share in the diet (accompanied by a higher milk yield) determined also an increase in the vitamin A and vitamin E content of milk, but it had no effect on β-carotene levels. The desirable changes in the concentrations of vitamin A and vitamin E, observed along with an increase in the content of concentrate the diet, indicate that their levels in the ration should be optimized.
Static dielectric constant of aqueous electrolyte solutions: is there any dynamic contribution?

We investigate the presence of dynamic cross correlation between ionic current and collective dipole moment fluctuations and the contribution of such dynamic cross correlations to the static dielectric constant of electrolyte solutions by means of a series of sufficiently long molecular dynamics simulations of aqueous NaCl and KCl solutions at different concentrations ranging from 0.88 M to 4.5 M.
Curvature and the Eigenvalues of the Laplacian

A famous formula of H. Weyl [17] states that if D is a bounded region of R d with a piecewise smooth boundary B, and if 0 > γ1 ≥ γ2 ≥ γ3 ≥ etc. ↓−∞ is the spectrum of the problem $$\displaystyle\begin{array}{rcl} \varDelta f =\big (\partial ^{2}/\partial x_{ 1}^{2} + \cdots + \partial ^{2}/\partial x_{ d}^{2}\big)f =\gamma f\quad \mbox{ in }D,& &{}\end{array}$$ (6.1.1a) $$\displaystyle\begin{array}{rcl} f \in C^{2}(D) \cap C(\overline{D}),& &{}\end{array}$$ (6.1.1b) $$\displaystyle\begin{array}{rcl} f = 0\quad \mbox{ on }B,& &{}\end{array}$$ (6.1.1c) then $$\displaystyle\begin{array}{rcl} -\gamma _{n} \sim C(d)(n/\mbox{ vol }D)^{2/d}\quad (n \uparrow \infty ),& &{}\end{array}$$ (6.1.2) or, what is the same, $$\displaystyle\begin{array}{rcl} Z \equiv \mathop{\mathrm{sp}}\nolimits e^{t\varDelta } =\sum _{ n\geq 1}\exp \big(\gamma _{n}t\big) \sim (4\pi t)^{-d/2} \times \mathop{\mathrm{vol}}\nolimits D\quad (t \downarrow 0),& &{}\end{array}$$ (6.1.3) where \(C(d) = 2\pi [(d/2)! ]^{d/2}\).
Chromosome 8 gain is associated with high-grade transformation in MPNST

One of the most common malignancies affecting adults with Neurofibromatosis type 1 (NF1) is the malignant peripheral nerve sheath tumor (MPNST), an aggressive and often fatal sarcoma which commonly arises from benign plexiform neurofibromas. Despite advances in our understanding of MPNSTpathobiology, there are few effective therapeutic options, and no investigational agents have proven success in clinical trials. To further understand the genomic heterogeneity of MPNST, and to generate a preclinical platform that encompasses this heterogeneity, we developed a collection of NF1-MPNST patient-derived xenografts (PDX). These PDX were compared to the primary tumors from which they were derived using copy number analysis, whole exome and RNA sequencing. We identified chromosome 8 gain as a recurrent genomic event in MPNST and validated its occurrence by FISH in the PDX and parental tumors, in a validation cohort, and by single-cell sequencing in the PDX. Finally, we show that chromosome 8 gain is associated with inferior overall survival in soft tissue sarcomas. Taken together, these data suggest that chromosome 8 gain is a critical event in MPNST pathogenesis, and may account for the aggressive nature and poor outcomes in this sarcoma subtype.
Thermodynamic model for diffusion controlled reaction rim growth in a binary system: Application to the forsterite−enstatite−quartz system

We present a thermodynamic model for diffusion controlled growth of a reaction rim of phase γ between the phases α and β in a two component system. We investigate the case, where the reactant phase α has planar, cylindrical and spherical geometry and is embedded in a matrix of phase β. We find that for non planar geometry and for the general case, where the molar volumes of the reactant phases are different, the rim growth rate depends on the matrix-inclusion arrangement. The model is applied to growth of enstatite reaction rims that form at quartz-forsterite interfaces. Two different geometrical setups are considered, namely a spherical grain of forsterite in a quartz matrix and a spherical quartz grain in a forsterite matrix. The enstatite rims are polycrystalline and transfer of the MgO and SiO2 components across the growing rim occurs by a combination of volume− and grain boundary diffusion. For enstatite rims that were grown at experimental conditions of 1000°C and 1 GPa (Milke and others, 2008) bulk mass transfer may be described by effective diffusion coefficients in the range of 1.8 · 10−17m2s−1 ≤ DSiO2 ≤ 1.1 · 10−16m2s−1 and 2.7 · 10−17m2s−1 ≤ DMgO ≤ 1.6 · 10−16m2s−1.
Cetyltrimethylammonium Bromide as an Efficient Catalyst for Regioselective Bromination of Alkoxy Naphthalenes with Trimethyl Benzyl Ammonium Tribromide: Synthetic and Kinetic Approach

Brominationof2-alkoxynaphthalene(2-ANP)anditsderivativeswithtrimethylben- zyl ammonium tribromide (TMBATB) did not proceed smoothly even under reflux conditions. But the addition of microconcentrations of cetyltrimethyl ammonium bromide (CTAB) to the reaction afforded dramatic rate accelerations as well as good-to-excellent yield of the products ranging from 70% to 90%. Reactions underwent regioselective monobromination at 1-position of 2-alkoxynaphthalene. The rate of bromination has been followed conductometrically. The reaction kinetics indicatedfirst-order kinetics in (2-ANP) as well as in (TMBATB). Kinetic results
Low-Temperature Growth and Doping of CdTe Epilayers on CdTe Substrates in a Remote-Plasma-Assisted MOCVD System for Nuclear Radiation Detector Applications

Homoepitaxial growth and n-type impurity doping of CdTe layers at low substrate temperatures were carried out for their applications in nuclear radiation detector fabrication. The grown epilayers were characterized by scanning electron microscopy, photoluminescence and Hall measurements. Highly conductive iodine doped layers could be obtained at a substrate temperature of 150°C, and these layers were found to be more suitable for radiation detector applications than other layers grown at higher substrate temperatures. The surface morphology of these homoepilayers was not very smooth, however, distinct edge emission and deep level emission bands were observed on the PL spectra at 20 K. A diode-type radiation detector fabricated using this low temperature growth and doping technique, exhibited very good rectification property with a very low value of reverse bias leakage current and an excellent nuclear radiation detection property.
Influence of the stabilization temperature on textural and structural features and ion release in SiO2-CaO-P2O5 sol-gel glasses

Two different SiO2−CaO−P2O5 glasses have been synthesized by the sol−gel method, and the stabilization of the gel glasses was carried out at temperatures between 500 and 800 °C. The different thermal treatments lead to changes in the structural and textural properties. When the glasses were soaked in a buffered solution, the activation energy for calcium release increased with the stabilization temperature. The changes in the silicon release were found to be closely related to the changes in textural properties and network density. The evolution of such changes depended on the chemical composition of the glasses. As an assumption, the differences in behavior between both compositions can be explained in terms of the chemical structure of the glasses. The Ca/Si ratio appears to play a fundamental role in this behavior.
A role for surface reactivity in TiO2 and quartz-related nanoparticle pulmonary toxicity

A variety of pulmonary hazard studies in rats have demonstrated that exposures to ultrafine or nanoparticles (generally defined as particles in the size range < 100 nm) produce more intensive inflammatory responses when compared with bulk-sized particle-types of similar chemical composition. However, this common perception of greater nanoparticle toxicity is based on a limited number of studies, conducted primarily with titanium dioxide and carbon black particle-types. Apart from variables such as particle size and surface area, it is conceivable that several additional physicochemical particle characteristics could play more significant roles in facilitating the development of nanoparticle-related toxicity; particularly when considering particle surface-cell interactions. These include but are not limited to: (i) Surface reactivity of particle-types; (ii) surface coatings; (iii) aggregation/disaggregation potential; and (iv) the method of nanoparticle synthesis. We present results of pulmonary bioassay hazard/safety studies with quartz particles of varying sizes/surface areas. These demonstrated that intratracheal instillation exposures to fine-sized, Min-U-Sil quartz particles (0.5 µm [particle size] – 5 m2/g [surface area]) produced (persistent) enhanced pulmonary toxicity (inflammation, cytotoxicity, cell proliferation and/or histopathology) in rats when compared to nanoscale quartz particles (50 nm–31 m2/g), but not when compared to smaller nanoscale quartz sizes (e.g., 12 nm–91 m2/g). The toxicity results correlated with red blood cell hemolytic potency as a measure of particle surface reactivity. In a second pulmonary bioassay study in rats, pulmonary hazard effects were measured following exposures to three different ultrafine (nano) TiO2 particle-types, each with similar particle size distributions. The various TiO2 particles differed in their crystal structures and surface reactivity endpoints as measured by the Vitamin C yellowing assay. Moreover, the surface activity characteristics correlated with potency of hazard biomarkers as described above, in these dose/response, time-course studies. It is concluded that particle surface reactivity, rather than particle size/surface area endpoints correlated best with lung inflammatory potency following exposures to particles.
Enhanced tribological performance of rigid disk by using chemically bonded lubricant

Nonreactive perfluoropolyether lubricants were processed by ultraviolet (UV) radiation to make them chemically bonded to thin film magnetic disks. The tribological performance of these disks was then investigated. Disks with a range of 30–50 A thick perfluoropolyether lubricant, were treated by using the different sources of UV radiations in air, argon, and nitrogen atmospheres. By changing the power density from 40 mW/cm2 to 50 W/cm2 and UV wavelength 185 to 365 nm, in either dry nitrogen or argon gas, a maximum of 38 A of lubricant was chemically bonded to the thin film disks. Stiction and friction forces during 1 rpm testing were dramatically decreased with the increase in UV exposure time. Contact‐start‐stop test performance of disks with ∼15%–30% of chemically bonded lubricant was also significantly enhanced. An optimum amount of chemically bonded lubricant provides excellent tribological performance for thin film disks.
Midgap states and charge inhomogeneities in corrugated graphene

We study the changes induced by the effective gauge field due to ripples on the low energy electronic structure of graphene. We show that zero-energy Landau levels will form, associated with the smooth deformation of the graphene layer, when the height corrugation, $h$, and the length of the ripple, $l$, are such that ${h}^{2}∕la\ensuremath{\gtrsim}1$, where $a$ is the lattice constant. The existence of localized levels gives rise to a large compressibility at zero energy and to the enhancement of instabilities arising from electron-electron interactions including electronic phase separation. The combined effect of the ripples and an external magnetic field breaks the valley symmetry of graphene, leading to the possibility of valley selection.
Semiclassically optimized complex absorbing potentials of polynomial form. II. Complex case

In a previous paper [J. Chem. Phys. 118, 17 (2003)], we presented an optimal, pure imaginary complex absorbing potential (CAP) of polynomial form, for use with resonance and scattering calculations. The optimal CAP was derived by minimizing reflection and transmission, and was found to greatly reduce CPU time. In this paper, the previous analysis is extended to more general complex polynomial functional forms, and new CAPs are developed which are even more efficient than those of the previous work, especially for highly accurate calculations.
PREDICTING SOIL TEMPERATURES IN A SHORTGRASS STEPPE

This paper reports a simplified soil temperature model, developed to predict hourly and daily maximum and minimum soil temperatures under different amounts of plant cover. As input the model requires daily maximum and minimum air temperature (2 m), plant biomass, initial soil temperature, and the soil thermal diffusivity. The model was developed using hourly soil temperature from four treatments representing different degrees of plant cover during the 1977 growing season at a shortgrass prairie site in northeastern Colorado. Independent data showed that the root-mean-square error for the daily maximum and minimum soil surface temperature was within 3.71 and 1.19°C, respectively, and that daily maximum and minimum root zone soil temperatures (6, 10, 20, and 50 cm deep) had root-mean-square errors less than 2.4°C. Hourly soil temperatures had root-mean-square error terms of 4.42, 3.14, 2.87, and 1.64°C for the soil surface, 4-, 10-, and 20-cm soil depths, respectively. Differences between the predicted and observed soil temperatures generally decrease with depth. The simplified model uses minimum computer time and reduces data input needed to simulate soil temperatures; however, daily maximum and minimum soil temperature data are needed to estimate some of the parameter values.
Controlling the Number of Arms of Polymer Stars with a Fullerene C60 Core

Abstract Pure di‐ and tetra‐adducts can be obtained by grafting polystyrene (PS) chains onto C60 via an atom transfer radical addition. Stars with a C60 core and exactly six PS arms of molar mass ranging from 1000 to several 100,000 are easily produced by adding an excess of PSLi to the fullerene. Tri‐ to penta‐adducts can be prepared by controlling the stoichiometry PSLi/C60. The number of grafts on the fullerene can be extended to seven or eight by initiation of the anionic polymerization of an adequate monomer with a “living” hexa‐adduct or by grafting onto this latter an halogen terminated polymer.
Experimental and Theoretical Investigation of Degradation Mechanisms by Particle Coarsening in SOFC Electrodes

Performance degradation data obtained from single solid oxide fuel cells, tested at 850 °C with air and humidified H2 and using Ni‐YSZ anode supported cells, are presented here. Microscopic investigation is carried out on both anode and cathode to quantify variations in the morphology at different operation times. The comparison between the measurements on the cells and the SEM image analysis allows to conclude that there is no relationship between the initial cell activation and microstructural modifications of the electrodes. On the other hand, it was found that cell degradation is strictly related to the coarsening of Ni particles occurring in the anode. A theoretical analysis based on an electrode micromodel has been performed in order to compare the variation in performance, expected from particle size change, with the observed data. The model confirmed the conclusions of the experimental results.
Effects of metal protection coils on thermocouple EMF in multi-anvil high-pressure experiments

Abstract Metallic coils (in most cases Cu coils) are often used in high-pressure experiments to protect thermocouple wires. In this paper we show that these coils have important influences on thermocouple EMF and therefore on the temperature measurements. We tested this effect by measuring EMF from Cu coiled single wires of chromel and alumel, and, further, we conducted experiments to compare the EMF from W5Re-W26Re thermocouples with and without Cu coils attached to them. The results show systematic differences in thermocouple readings; the EMFs from W-Re thermocouples with Cu coils give systematically lower values than EMFs from thermocouples without Cu coils. The results were analyzed using a simple model. The difference in thermocouple EMFs between thermocouples with and without protection coils is given by where Ei and Ri are the EMF and the electrical resistance of metal i in the portion of the Cu coil, and the subscripts 1+, 1-, and 2 indicate positive thermocouple metal, negative thermocouple metal, and coil metal, respectively. The addition of a coil with different metal has a large effect . the ΔETC will be close to . (E1+ - E1-) < 0 when the resistance of the coil is significantly smaller than that of a thermocouple wire. For a Cu coil and W-Re thermocouple, R1+, 1- >> R2 and therefore thermocouple readings with a Cu coil will lead to underestimation of the real temperature. Under common experimental conditions with a multi-anvil apparatus, the error in the temperature estimate caused by Cu protection coils is ~100.150 K for a peak temperature of 1600.2000 K.