Miracle-dz/UniFAR-FTUs huggingface dataset:
Formaldehyde Release From Urea-Formaldehyde Bonded Wood Products

Abstract During the past decade significant progress has been made in reducing formaldehyde release from UF-bonded wood products. The purpose of this work was to test formaldehyde release from medium density fibreboard (MDF) manufactured in a commercial pilot plant using seven different UF resins with molar ratios between 1.85 and 1.05 that were available in spring 1983. Formaldehyde release measured with the 2 hr. U.S. desiccator test ranged from 8.6 mg/l to 0.3 mg/l after 6 weeks. European perforator standard values ranged from 80 mg/100 g to 9 mg/100 g. Low molar ratio resin produced MDF with good mechanical properties while yielding formaldehyde release rates that were sufficiently low to meet the requirement of the German wood product class E-1 and the 0.1 ppm requirement of ASHRAE 62-1981 or similar standards for minimum acceptable indoor air quality at reasonable product loading ratios.
Distance and Scalar HH-Coupling Correlations in Transition Metal Dihydrides and Dihydrogen Complexes †

The bond-valence bond-length concept has been applied to derive a correlation between the hydrogen−hydrogen and the metal−hydrogen distances in the nonclassical dihydrogen complexes and classical transition metal dihydrides. The parameters of this correlation are similar to those for strong hydrogen-bonded systems. The predicted correlation is supported by 18 neutron structures of transition metal dihydrides or dihydrogen complexes and 2 neutron structures of transition metal trihydride complexes. It is also shown that the bond-valence bond-length concept can also be used to establish a correlation between the dihydrogen distance rHH in dihydrogen/dihydride complexes and the scalar coupling constants JHH/JHD/JHT in the different isotopomers of these complexes.
Soil pH was the main controlling factor of the denitrification rates and N2/N2O emission ratios in forest and grassland soils along the Northeast China Transect (NECT)

The Northeast China Transect (NECT) is a mid-latitude terrestrial transect in the International Geosphere-Biosphere Programme. Its major environmental gradient is precipitation, which gradually decreases from the eastern mountainous region to the western pastoral area. In this investigation, a series of forest and grassland soils were sampled along the NECT, and the denitrification rate and nitrogen/nitrous oxide (N2/N2O) ratio were studied under laboratory conditions by the acetylene inhibition method. Forest soils were all acidic, with soil pH values ranging from 4.3 to 5.9 and soil organic carbon ranging from 32.0 to 54.7 g kg−1. Soil pH for grassland soils was approximately neutral, ranging from 6.1 to 7.8, while soil organic carbon ranged from 14.8 to 32.2 g kg−1. The highest denitrification rates (average 1.1 ± 0.2 mg N kg−1 h−1) were in grassland soils in the western part of the NECT, while the lowest were in forest soils (average 0.25 ± 0.1 mg N kg h−1) in the eastern part of the NECT. The denitrification rate increased linearly from east to west along the NECT (p < 0.01). Nitrous oxide was the main component of gas products of denitrification in forest soils, while N2 was the dominant denitrification product in grassland soils. The ratio of N2/N2O increased linearly from east to west along the NECT (p < 0.01). Soil pH was the best predictor of the denitrification rate and of the N2/N2O ratio in grassland and forest soils along the NECT.
Dielectric Properties of Cobalt Oxide, Nickel Oxide, and Their Mixed Crystals

Dielectric constant κ′, loss κ″, and conductivity σ of single crystals of CoO, NiO, and mixed crystals of CoO–NiO as a function of frequency from 102 to 1010 cps and temperature from −193°C to 400°C have been determined. The dielectric constant κ′ is constant (12.9 at 25°C) in the whole frequency range in CoO. It decreases with frequency in NiO and mixed crystals CoO–NiO. In NiO κ′ reaches a constant value (11.9 at 25°C) at 105 cps, and in CoO·NiO (12.3 at 25°C) at 1010 cps. The dielectric constants extrapolated to 0°K are 10.9, 10.0, and 9.1 for CoO, CoO·NiO, and NiO, respectively. In all crystals the dielectric constant increases exponentially with temperature. Using modified Debye equations, two thermal activation energies for κ′ have been obtained: 0.042, 0.027, and 0.018 eV for temperatures below 40°C (frequency‐independent region); 0.33, 0.20, and 0.16 eV for temperatures above 40°C, for CoO, NiO, and CoO·NiO (frequency‐dependent region). The plot of log σ vs 1/T gives straight lines for CoO from 40.
Extremely Durable High‐Rate Capability of a LiNi0.4Mn0.4Co0.2O2 Cathode Enabled with Single‐Walled Carbon Nanotubes

A binder-free LiNi{sub 0.4}Mn{sub 0.4}Co{sub 0.2}O{sub 2} cathode fabricated with 5 wt. % single-walled carbon nanotubes (SWNTS) shows excellent cycling performance at rates of 10C (Charge/discharge in 6 minutes). In contrast, a LiNi{sub 0.4}Mn{sub 0.4}Co{sub 0.2}O{sub 2} electrode prepared by conventional methods without SWNTs has a significantly lower capacity. Based on the morphology and structural analysis, this exceptional rate capability is due to highly intimate contact between the long crystalline SWNT ropes and the active cathode material, ensuring fast diffusion of ions and electrons during cycling and resulting in sustainable capacity at high rates for 500 cycles.
Comparative Analysis of Phenolic Composition and Antioxidant Effect of Seed Coat Extracts of Four Cowpea (Vigna unguiculata) Varieties on Broiler Meat

Seed coat crude extracts of white-coloured ITA-256, white and brown-coloured TVS-716, deep browncoloured IT-90K and light brown-coloured Ife brown cowpea varieties were analyzed for the presence and amount of total phenol, tannin and flavonoid content. Crude extracts of the cowpea varieties were analyzed for antioxidant activity using the Thiobarbituric Acid (TBA) assay. The seed coat extracts were added separately to 200 g of minced broiler meat sample at the rate of 0.05% of the weight of the meat and their effect compared to that of the synthetic antioxidant, butylated hydroxyl anisole (BHA) added to the meat at the rate of 0.05%. Each sample was divided into 16 parts of 12.5 g each. Eight of these were cooked while the other 8 parts were left raw. Antioxidant effect of the seed coat extracts was determined during refrigerated storage of raw and cooked minced broiler meat. All the cowpea varieties studied except TVS-716 contained phenol, tannin and flavonoids. TVS-716 contained only phenol and tannin. Seed coats extract from Ife brown contained higher levels of total phenol, tannin and flavonoids than the corresponding samples of IT90K, ITA-256 and TVS-716. IT-90K had higher tannin content than ITA-256 and TVS-716 but its phenol and flavonoids content are not significantly different (P>0.05) from that of ITA-256. TBA assay shows that all the additives and BHA were able to reduce lipid oxidation in broiler meat. This was shown by lower TBARS values in broiler meat samples with added additives compared to the control samples (meat without additives). Seed coat extracts of Ife brown, ITA-256 and IT-90k reduce lipid oxidation more than BHA in raw broiler meat samples but are less potent than BHA in cooked meat samples. Seed coat extracts of Ife brown was more effective than other cowpea varieties in reducing lipid oxidation in both cooked and raw meat samples. The antioxidant potential of IT-90K was not significantly different (P>0.05) from that of ITA-256 while TVS-716 exhibited the least antioxidant potency.
Solvent Effects in the Electron Spin Resonance Spectra of Some Phenoxyl, Nitroxide, and Anilino Radicals

The electron spin resonance spectra of 2,6-di-t-butyl-4-methylphenoxyl (I) and 2,4,6-tri-t butylphenoxyl (II) have been observed under high resolution, and it has been shown experimentally that the para methyl proton hyperfine splitting (aCH3H) in the radical (I) increases, while, inversely, the meta proton hyperfine interaction decreases, as the dipole moment of the solvent (μ) increases. The relationship between these two variables can be written as:a(μsolv)=a(μsolv=0)+K·μsolv,where μsolv is the dipole moment of the solvent and where K is the constant of proportionality. Further study of diphenyl nitric oxide (DPNO) (IV) and di-p-anisyl nitric oxide (DPANO) (V) radicals has shown this to be a general form of the solvent effect. However, in the case of various kinds of solvents with OH or NH groups, it has been found that aN deviates from the equation. This phenomenon has been explained qualitatively by the effect of hydrogen bonding. Therefore, the variation in the coupling constants has generally been .
Image reconstruction using wavelet multi-resolution technique for time-domain diffuse optical tomography

It is generally believed that the inverse problem in diffuse optical tomography (DOT) is highly ill-posed and its solution is always under-determined and sensitive to noise, which is the main problem in the application of DOT. In this paper, we propose a method on image reconstruction for time-domain diffuse optical tomography based on panel detection and Finite-Difference Method, and introduce an approach to reduce the number of unknown parameters in the reconstruction process. We propose a multi-level scheme to reduce the number of unknowns by parameterizing the spatial distribution of optical properties via wavelet transform and then reconstruct the coefficients of this transform. Compared with previous traditional uni-level full spatial domain algorithm, this method can efficiently improve the reconstruction quality. Numerical simulations show that wavelet-based multi-level inversion is superior to the uni-level algebraic reconstruction technique.
On the Stability of LiFePO4 Olivine Cathodes under Various Conditions (Electrolyte Solutions, Temperatures)

LiFePO 4 is one of the most important cathode materials for Li-ion batteries studied over the past few years. Impressive work has revealed important structural aspects and the correlations between structure and composition and electrochemical properties. Fewer efforts have been devoted to the surface chemical aspects of this material. We report herein on a study of the stability aspects of LiFePO 4 at two temperatures, 30 and 60°C. Three types of solutions were used based on EC-DMC 1:1 solvent mixtures those involving no acidic contamination (using LiClO 4 as the electrolyte), those contaminated by HF(using LiPF 6 as the Li salt), and LiPF 6 solutions deliberately contaminated with H 2 O. Iron dissolution from LiFePO 4 in these electrolytes, as well as the electrochemical response as a function of solution composition and aging, were studied at the two temperatures. The effect of additives that neutralize acidic species in solution was also studied. In general, LiFePO 4 develops a unique surface chemistry. Highly stable behavior of LiFePO 4 cathodes, without any substantial iron dissolution at elevated temperatures, was observed and measured when the solution contains no acidic or protic contaminants.
Nitrifier denitrification can be a source of N2O from soil: a revised approach to the dual‐isotope labelling method

Nitrifier denitrification (i.e. nitrite reduction by ammonia oxidizers) is one of the biochemical pathways of nitrous oxide (N2O) production. It is increasingly suggested that this pathway may contribute substantially to N2O production in soil, the major source of this greenhouse gas. However, although monoculture studies recognize its potential, methodological drawbacks prohibit conclusive proof that nitrifier denitrification occurs in actual soils. Here we suggest and apply a new isotopic approach to identify its presence in soil. In incubation experiments with 12 soils, N2O production was studied using oxygen (O) and nitrogen (N) isotope tracing, accounting for O exchange. Microbial biomass C and N and phospholipid fatty acid (PLFA) patterns were analysed to explain potential differences in N2O production pathways. We found that in at least five of the soils nitrifier denitrification must have contributed to N2O production. Moreover, it may even have been responsible for all NH4+‐derived N2O in most soils. In contrast, N2O as a by‐product of ammonia oxidation contributed very little to total production. Microbial biomass C and N and PLFA‐distinguished microbial community composition were not indicative of differences in N2O production pathways. Overall, we show that combined O and N isotope tracing may still provide a powerful tool to understand N2O production pathways, provided that O exchange is accounted for. We conclude that nitrifier denitrification can indeed occur in soils, and may in fact be responsible for the greater proportion of total nitrifier‐induced N2O production.
X-ray diffraction and Raman spectroscopic study of clinopyroxenes with six-coordinated Si in the Na(Mg0.5Si0.5)Si2O6-NaAlSi2O6 system

Abstract Five clinopyroxenes containing various amounts of six-coordinated Si (VISi) in the Na(Mg0.5Si0.5) Si2O6 (NaPx)-NaAlSi2O6 (jadeite) system have been synthesized at 15 GPa and 1600 °C and their structures studied with single-crystal X-ray diffraction and Raman spectroscopy. The results show that clinopyroxenes with VISi ≤ 0.33 atoms per formula unit (apfu) possess C2/c symmetry, whereas those with VISi ≥ 0.45 apfu crystallize with P2/n symmetry. There is an obvious discontinuity in the unit-cell parameters a, β, and V as the VISi content increases from 0.33 to 0.45 apfu, suggesting that the C2/c-P2/n transition is first-order in character, rather than tricritical as reported for the transition from jadeite/diopside/augite to omphacite. The Mg and VISi cations in the P2/n structure are completely ordered into two nonequivalent octahedral sites, M1 and M1(1), respectively, with M1 being appreciably more distorted than M1(1). With increasing mean distance, the mean tetrahedral distance increases, whereas the O3-O3-O3 angle of the tetrahedral chain decreases systematically, consistent with the structural variation trends found in the jadeite-diopside system. A comparison of the Raman spectra reveals that the C2/c-P2/n transition is characterized by the splitting of many Raman bands in C2/c clinopyroxenes into doublets in P2/n, and such splitting becomes more pronounced with increasing VISi. For C2/c clinopyroxenes, all Raman bands become progressively broader with the increased substitution of (Si4+ + Mg2+) for Al3+. In addition, several new Raman bands, attributable to the presence of VISi, are observed. Together with previous data, we suggest that the maximum VISi content allowed for an Mg/Al dominated octahedral site is close to ~35%, above which VISi and Mg/ Al are likely to be ordered into distinct sites.
La mort annoncée des «quatre compétences» - pour une prise en compte du répertoire communicatif des apprenants en classe de FLE

L’expression quatre competences est frequemment utilisee par les enseignants de Francais Langue etrangere pour designer le developpement des competences des apprenants en comprehension (orale et ecrite) et en production (orale et ecrite). Dans cet article, nous montrons tout d’abord que cette appellation provient d’un probleme de traduction de l’anglais et qu’elle peut conduire a negliger certaines dimensions fondamentales de l’enseignement/apprentissage, en particulier le "deja-la" des apprenants. Cette clarification nous amene a presenter la terminologie et les principes retenus dans le Cadre europeen commun de reference pour les langues - permettant de dissiper les ambiguites - et leur application possible sur le terrain de la classe de Francais Langue etrangere. Ainsi, en pointant une expression courante mais non adequate en vient-on a defendre une approche visant a developper le repertoire communicatif d’un apprenant de langue et a faire de lui un acteur social, plurilingue, a part entiere.
Fluorophore-doped calcium phosphate nanoparticles for non-toxic biomedical applications

We report the synthesis of optically doped calcium phosphate nanoparticles (CPs), with and without surface coating with the biocompatible polymer chitosan. Trisilanol was used to restrict the size of calcium phosphate in the nano-dimension. The diameter of the nanoparticles was found to be less than 200 nm. A powder X-ray diffraction (XRD) study demonstrated the crystalline nature of the nanoparticles, largely matching with the XRD pattern of hydroxyapatite, which is the most common crystalline form of calcium phosphate. Upon fluorophore encapsulation in these nanoparticles, the optical properties of the fluorophore not only remained preserved, but also had enhanced stability against chemical quenching in comparison to its free form. In vitro analysis showed that these nanoparticles are taken up by cells, the uptake being enhanced upon coating with chitosan. No sign of in vitro cytotoxicity was observed in the dosages tested. Preliminary in vivo studies showed that oral administration of these nanoparticles in healthy Wistar rats, at a dose of 2000 mg kg−1, did not result in any visible sign of acute toxicity. These results highlight the potential for CPs to be used as safe and efficient agents for optical bioimaging and drug delivery.
Bacterial communities in manganese nodules in rice field subsoils: Estimation using PCR-DGGE and sequencing analyses

Abstract The phylogenetic positions of bacterial communities in manganese (Mn) nodules from subsoils of two Japanese rice fields were estimated using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis followed by sequencing of 16S rDNA. The DGGE band patterns and sequencing analysis of characteristic DGGE bands revealed that the bacterial communities in Mn nodules were markedly different from those in the plow layer and subsoils. Three out of four common bands found in Mn nodules from two sites corresponded to Deltaproteobacteria and were characterized as sulfate-reducing and iron-reducing bacteria. The other DGGE bands of Mn nodules corresponded to sulfate and iron reducers (Deltaproteobacteria), methane-oxidizing bacteria (Gamma and Alphaproteobacteria), nitrite-oxidizing bacteria (Nitrospirae) and Actinobacteria. In addition, some DGGE bands of Mn nodules showed no clear affiliation to any known bacteria. The present study indicates that members involved in the reduction of Mn nodules dominate the bacterial communities in Mn nodules in rice field subsoils.
Self-catalysed growth of zinc oxide nanowires

Single-crystal nanowires of zinc oxide were prepared by a novel self-seeded vapour–liquid–solid (VLS) growth method using ultrasonic spray-assisted chemical vapour deposition, in which liquid Zn droplets were used as ‘catalysts’. In this approach, a nanocrystalline seed layer was first deposited, by direct decomposition of a zinc acetate precursor solution, onto a glass substrate at a temperature slightly below the melting point (420 °C) of Zn. ZnO nanowires were subsequently grown at a temperature above the melting point of Zn. From transmission electron microscopy, solidified Zn/ZnO droplets were observed on the ends of the ZnO nanowires. A novel mechanism for self-seeded growth of ZnO by the ‘vapour (Zn acetate)–liquid (Zn)–solid (ZnO)’ growth mechanism is described. The main advantage of the method is that it is clean, since growth occurs in the absence of a second phase catalyst.
Mn(II) chelates with potential interest for MRI

Magnetic Resonance Imaging (MRI) has become one of the most successful diagnostic imaging modalities. A large number of MRI scans use paramagnetic contrast agents (CA), to enhance the image’s contrast. Gd(III), with seven unpaired electrons and a long electronic relaxation time, is the most used metal ion for the preparation of CA. Mn(II) is also a good candidate for MRI contrast agents due to its five unpaired d electrons, a favorable electronic relaxation time, and the lability of the coordinated water molecule(s). Presently, there is one approved Mn(II)-based CA, Teslascan® ([MnDPDP] 4- , DPDP 6- = N,N’dipyridoxylethylenediamine-N,N’-diacetate-5,5’-bis-(phosphate), Figure 1). Due to toxicity problems, the paramagnetic ions should be administrated as metal complexes of high thermodynamic and kinetic stabilities. Macrocyclic ligands are known to form such stable metal complexes. The presence of hydrophobic moieties in chelates allows them to bind to human serum albumin (HSA), the most abundant serum protein. The presence of binding sites with affinity for lipophilic groups [1] can be exploited as a strategy to increase the blood retention of the CA and also to enhance the relaxivity by increasing the tumbling time (τr) [2]. The formation of micelles can also be used with the goal of increasing the τr. Bifunctional ligands can be coupled to targeting molecules (i.e. peptides) with high affinity for biological receptors, preserving the coordination properties of the chalator. This consists in another strategy to target CA. In this work, we developed three new triazapolycarboxylate ligands for Mn(II), NODAHep (1,4,7-triazacyclononane-N,N’-diacetate-N’’-heptanil), NODABA (1,4,7triazacyclononane-N,N’-diacetate-N’’-bensoate), and NODAHA (1,4,7-triazacyclononaneN,N’-diacetate-N’’-hexanoate) (Figure 1). These chelators are pentadentate, leaving one coordination site of the metal coordination sphere available for one water molecule. NODAHep has a lipophilic side chain, designed to endow the chelate with the capacity of forming micelles and of interacting non-covalently with HSA. This was expected to increase τr and consequently to increase the relaxivity. NODABA and NODAHA are bifunctional ligands that present a free carboxylic group in the pendant lateral chain, allowing their conjugation to targeting molecules. 1 H NMRD and 17 O NMR studies were performed for the three Mn(II) chelates, showing relaxivity values comparable to those of Gd(III) chelates with one water molecule in the inner coordination sphere of the metal ion. Potentiometric titrations allowed the determination of the pKa’s of the ligands and the thermodynamic stability constants of the Mn(II) and Zn(II)
Controlled-Release Multiple-Units and Single-Unit Doses a Literature Review

AbstractThe strong influence exerted by the greatly varying normal gastrointestinal functions on the therapeutic value of a controlled-release single-unit dose is elucidated by a review of the literature. In this setting, the multiple-units dose comprising hundreds of mini-depots presents a highly preferable alternative which is due to a greater predictability and reproducibility of its therapeutic effect as well as a lowered risk of side effects.
Flexible free-standing 3D porous N-doped graphene-carbon nanotube hybrid paper for high- performance supercapacitors†

The nanoarchitecture of carbon with assembled building blocks on diverse scales is of great importance for energy storage. Herein, we demonstrate high-performance supercapacitors by building a threedimensional (3D) porous structure that consists of a N-doped graphene–carbon nanotube (CNT) hybrid. The 3D porous nitrogen-doped graphene–CNT (p-N-GC) hybrid paper was fabricated by using polystyrene (PS) colloidal particles as a sacrificial template, followed by calcination to remove PS to generate macropores, to reduce graphene oxide (GO) into graphene, and to realize N-doping simultaneously by one step. The as-prepared p-N-GC paper with high porosity, conductivity and flexibility has a high specific capacitance of 294 F g � 1 at a current density of 1 A g � 1 in 6 M KOH electrolyte solution, as well as good rate capability and cycle stability. The greatly enhanced electrochemical performance can be ascribed to the synergistic effect of the 3D porous nanostructure, effective CNT intercalation, and nitrogen-doping, suggesting that p-N-GC as novel electrode materials may have potential applications in high-performance energy storage devices.