Miracle-dz/UniFAR-FTUs huggingface dataset:
Creation of Reactive Centers on Cotton

Dyeing of acrylamidomethylated cellulose (AMC) with dyestuffs containing nucleophilic groups is studied. It is found that the presence of the pendant double bonds on AMC is advantageous in effecting concurrent dyeing and wash-wear finishing. The loss in tensile strength is minimal. Several interesting results relating to this novel pro cedure are reported.
A Facile Route to Phosphanylborohydrides:Synthesis, Crystal Structure and Spectroscopic Properties of 1,2-Bis(Diphenylphosphinoborane)Ethane

A novel and simple synthetic way using NaBH4 in the mixture of H2O-THF was applied to prepare 1,2-bis(diphenylphosphinoborane)ethane, dppe(BH3)2, in high yield and purity. The phosphanylborohydride compound dppe(BH3)2 was isolated in the form of colorless crystals and characterized by single crystal X-ray diffraction, 1 H, 13 C, 31 P and 11 B NMR spectroscopy. Prismatic colorless crystals of dppe(BH3)2 were obtained in monoclinic crystal system and space group P21 with two asymmetric units in the unit cell. Lattice parameters were: a = 11.657(2), b = 17.237(2), c = 12.764(2) A,  = 98.735(14)˚, 2535.0(7) A 3 .
Pore-width-dependent ordering of C2H5OH molecules confined in graphitic slit nanospaces

The X-ray diffraction (XRD) of C2H5OH molecules confined in slit-shaped graphitic micropores of activated carbon fibers having different pore widths was measured at 303 K. The effect of the pore width in the range 0.7−1.1 nm on the molecular assembly structure of C2H5OH in the micropores was examined. The XRD patterns were analyzed by use of the electron radial distribution function (ERDF) analysis. The densities of C2H5OH molecular assemblies in micropores were determined by C2H5OH adsorption at 303 K and N2 adsorption at 77 K. The density of C2H5OH molecular assemblies in the 0.9 and 1.1 nm pores was close to the solid density of C2H5OH. The ERDFs showed that the first and second nearest-neighbor peaks shift to a shorter distance with a decrease of the pore width while their peak heights increase. These changes of the ERDFs coincided very well with the adsorbed density of C2H5OH, indicating that the serious confinement by the micropores gives rise to the solidlike ordering even at 303 K.
Evaluation of available P with different extractants on Guatemalan soils

Abstract The high P fixation capacity of soils rich in x‐ray amorphous minerals has been well documented. Some Andisols in central Guatemala which have received additions of volcanic ash have extraordinarily high extractable P levels with acidic extractant. These ash materials have low fixing capacities but they weather rapidly. This study examined the relationship between different soil P tests on soils from Guatemala. The study area has a strong volcanic influence. Some volcanos are still active, from which the ash being deposited is rich in apatite. Age and composition of the parent materials exert the strongest influence on soil properties. Thirty‐two soils from the southern part of Guatemala were divided according to their classification and soil properties. Chemical methods (Bray I and Mehlich I) were compared to two other soil test techniques (Pi strip and Resin‐strip). Phosphate retention characteristics were also measured. In general, very good correlations were found between all methods on soils.
Evidence for the Formation of Nitrogen Islands on Rhodium Surfaces

Kinetic evidence is presented for the formation of nitrogen-atom islands on Rh(111) surfaces. The deposition of atomic nitrogen on that surface was carried out via the steady-state conversion of NO with CO by using effusive collimated beams. Isotopic labeling experiments were performed where 14N-dosed surfaces were subsequently exposed to 15NO + CO gas mixtures for varying times. Subsequent temperature-programmed desorption indicated a nonstatistical distribution of isotopes in the resulting molecular nitrogen, the yield of the mixed 14N15N isotopomer being significantly lower than that expected on statistical grounds. Monte Carlo simulations were used to explain the observed isotopic distributions in terms of the formation of islands with the nitrogen isotopes distributed in a layered structure, the 14N atoms in a core surrounded by a 15N outer shell.
PHOTOELECTROCHEMICAL REDUCTION OF CO2 IN A HIGH-PRESSURE CO2 + METHANOL MEDIUM AT P-TYPE SEMICONDUCTOR ELECTRODES

Photoelectrochemical CO2 reduction was examined in a high-pressure (40 atm) CO2 + methanol medium using the p-type semiconductor electrodes p-InP, p-GaAs, and p-Si. With the p-InP photocathodes, current densities up to 200 mA cm-2 were achieved, with current efficiencies of over 90% for CO production, while hydrogen gas evolution was suppressed to low levels. At high current densities and CO2 pressures, the CO2 reduction current was found to be limited principally by light intensity. Of the various factors that were found to influence the product distribution, including the concentrations of added water and strong acid, CO2 pressure was the most critical factor. We propose that the adsorbed (CO2)2•- radical anion complex reaches high coverages at high CO2 pressures and is responsible for both the high current efficiencies observed for CO production and the low values observed for H2 evolution. Furthermore, we propose that this adsorbed complex is responsible for stabilizing all three semiconductor electro.
Old Silks Endowed with New Properties

High-performance regenerated silkworm Bombyx mori silk fibers with new properties that mimic those of spider silk can be produced through a wet spinning process modified with an immersion postspinning drawing (IPSD) step. IPSD fibers show the ability to recover from irreversible deformation, and their tensile behavior can be tailored repeatedly, features solely exhibited until now by natural spider silk. It is further shown that the new properties emerge from a microstructure that is closer to that of spider than to natural silkworm silk. This work demonstrates that processing plays a role at least comparable to that of the amino acid sequence in the final properties of the material. The spinning process does not only modify the mechanical parameters of the fiber but also can even prompt the emergence of new properties, opening a wide range of new applications for regenerated silk fibers. It also represents a significant change of the paradigm in the field of biomimetics, given that it relaxes the conditi.
Free radical catalysed additions to the double bond of diketene: a synthesis of novel oxetan-2-ones

Free radical-catalysed additions to the exocyclic double bond of diketene are described. Thiols give unstable 4-thiomethyloxetan-2-one adducts which could be oxidised to their more stable sulphoxides or sulphones. Addition of a range of P–H compounds led, with a few exceptions, to stable phosphorus-substituted 4-methyloxetan-2-ones. The radical-catalysed chlorination of diketene by sulphuryl chloride has been shown to give 4-chloro-4-chloromethyloxetan-2-one. Further 4-halogeno-oxetan-2-ones were prepared by addition of halocarbons such as carbon tetrachloride, bromotrichloromethane, and carbon tetrabromide and of trichloromethanesulphenyl chloride to diketene.
Optimal and Near-optimal Detectors for Acquisition of the GPS L5 Signal

Acquisition of GPS signals is typically accomplished by conducting a two-dimensional search of codephase and Doppler using multiple correlators. For each codephase/Doppler value, a detector is used to decide whether the signal is present or not present. This paper derives an optimal detector for the GPS L5 signal in the presence of additive white Gaussian noise. Simplified detectors are also derived as limits of the optimal detector in low- and high- signal-to-noise (SNR) conditions. Monte-Carlo simulation results are presented that demonstrate the performance of the optimal and nearoptimal detectors. For short dwell times, the high-SNR approximation to the optimal detector is the most promising. It significantly outperforms previous noncoherent detectors with only a moderate increase in receiver complexity.
A Short and Convenient Synthesis of Enantiopure cis- and trans-4-Hydroxypipecolic Acid

The synthesis of (2S,4R)- and (2R,4R)-4-hydroxypipecolic acid has been realized from commercial ethyl (R)-4-cyano-3-hydroxybutanoate through palladium-catalyzed methoxycarbonylation of a 4-hydroxy-substituted lactam-derived vinyl phosphate followed by the stereocontrolled reduction of the enamine double bond. The stereoselective hydrogenation of the suitably 4-hydroxy-protected enantiomer afforded the cis-(2S,4R)-4-hydroxypipecolic acid product, obtained in 66% overall yield over seven steps. The trans-product (42% overall yield over 8 steps) was instead obtained by hydride conjugate addition to the same α,β-unsaturated ester.
Growth and self-assembly of BaCrO₄ and BaSO₄ nanofibers toward hierarchical and repetitive superstructures by polymer- controlled mineralization reactions

Highly ordered funnel-like BaCrO4 superstructures with a complex form and a remarkable self-similar growth pattern as well as very long BaSO4 fiber bundles with repetitive growth patterns can be readily generated by using sodium polyacrylate as a structure directing agent in the mineralization process. The formation of fibers and fiber bundles as well as finer morphological details can be effected by variations of the temperature, pH, and concentration.
Dielectric measurements with an open-ended coaxial probe

The paper is concerned with the use of an open-ended coaxial-line probe for making dielectric measurements on lossy materials. The input reflection coefficient of the probe is measured with a network analyser, and the permittivity is determined using an approximate circuit model for the probe admittance. Applying the cross-ratio invariance property of the bilinear transform to two such circuit models, we derive a simplified procedure that permits simultaneous calibration of the probe and error correction of the network analyser. Estimates of the resulting uncertainties are given, and the technique is illustrated with experimental measurements on known dielectric liquids between 50 MHz and 2.6 GHz.
Polynitro-substituted bispyrazoles: a new family of high-performance energetic materials

New polynitro-substituted bispyrazoles were synthesised and fully characterised in this study. Ammonium 4-(4′-amino-3′,5′-dinitro-1′-pyrazol)-3,5-dinitropyrazole (3), 4-(4′-amino-3′,5′-dinitro-1′-pyrazol)-1-amino-3,5-initropyrazole (6), diaminoguanidinium 4-(4′-amino-3′,5′-dinitro-1′-pyrazol)-3,5-dinitropyrazole (9), and 3,4,5-triamino-1,2,4-triazolium 4-(4′-amino-3′,5′-dinitro-1′-pyrazol)-3,5-dinitropyrazole (12) were further confirmed using single-crystal X-ray diffraction. The compounds exhibited excellent thermal stabilities, insensitivities and high detonation performance. The measured LC50 of the compounds suggested that their toxicities were lower than that of TNT and that for compound 3 even lower than that of TATB. Compound 5 demonstrates unprecedented overall performance: higher detonation velocity (VD = 8760–8981 m s−1), detonation heat (Qv = 7551 kJ kg−1) and explosive power (A = 1712 kJ g−1) than RDX, a decomposition temperature (Td = 297 °C) higher than that of HMX, and much lower toxicity (LC50 = 7 μg mL−1) than that of TNT, ranking it in a new generation of heat resistant, less sensitive and low environmental impact high energetic materials.
Azetidines: New Tools for the Synthesis of Nitrogen Heterocycles

Compared to other nitrogen heterocycles such as aziridines, pyrrolidines,or piperidines, the chemistry of azetidines is much less developed,probably because of their limited availability. In this account,recent synthetic routes to these strained heterocycles startingfrom readily available enantiomerically pure starting compoundswill be detailed. The ring strain in these heterocycles makes themexcellent candidates for nucleophilic ring-opening or ring-expansionreactions yielding higher ring systems or highly substituted acyclicamines. These useful transformations will be described in the secondsection of this account. 1 Introduction 1.1 Synthesis of Azetidines from β-Amino Alcohols 2 Synthetic Transformation of 2-Cyanoazetidines 3 Ring Expansion of Functionalized Azetidines 3.1 Ring Expansion to Pyrrolidines 3.2 Ring Expansion to Azepanes 4 Ring Opening of Azetidines and Azetidinium Ions 5 Reactivity of Azetidinium Ylides 6 Synthetic Applications 7 Concluding Remarks
Interactive toxic effect and distribution of heavy metals in phytoplankton

Assessing the interactive toxic effect of chemicals in the environment is becoming a matter of increasing public focus on and concern with ecotoxicological aspects. The purpose of this study is to find the relationship between an interactive toxic effect and distribution of heavy metals in algal cells. The green alga Chlorella ellipsoidea Gernec(IAMC-27) was cultured for 6 days in the presence of cadmium and/or chromium. Algal cells were divided into 4 fractions by centrifugation after the cells were disrupted using a French press. The amounts of the metals in each fraction were determined. The interaction effect between the two metals on algal growth was investigated. The amount of one metal taken up in the cells and the growth inhibition rate increased with the concentration of metals in the medium. The amount of one metal in the cells was increased due to the presence of the other metal. Accordingly, the growth inhibition rate also increased. The amounts of Cd accumulated in the soluble fraction and in the membrane fraction of algal cells were 50 and 20%, respectively, of the total amount in the cells. The presence of Cr changed the Cd concentration in both fractions to 40%. The amount of Cr accumulated in each fraction was almost the same in the absence of Cd. The amount of Cr accumulated in the cell wall fraction rose to 90% after 3 days of exposure and it stayed as high as 50% even at the end of the six-day study period in the presence of Cd. It was assumed that the presence of one metal influenced the distribution of the other metal in the cells, which resulted in the synergistic toxic effect. © 1994 by John Wiley & Sons, Inc.
Giant Faraday rotation in Cd1-xMnxTe (0 < x < 0.82) crystals

We investigated the magneto-optical properties of diluted magnetic semiconductors Cd1–xMnx Te crystals grown using a vertical Bridgman method. This material crystallizes in the zinc-blende structure for values of x < 0.82. The band-gap energy was depended on Mn mole fraction x linearly and increased with decreasing temperature. The increase of the energy gap with increasing x may be due to a decrease in the lattice constant. Faraday rotation as a function of photon energy with various Mn compositions for CdMnTe in the temperature range of 10–300 K has been measured. The Faraday rotation was increased as the photon energy increased near to that of the fundamental band gap. Verdet constant becomes larger since the effect of the sp -d exchange interaction is enhanced as the temperature is lowered. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Diffusion-kinetic modeling of the electron radiolysis of water at elevated temperatures

The temperature dependence of the chemistry in the track of a fast electron in water has been examined with a deterministic diffusion-kinetic model. The model calculations suggest that there is an increase in the yields of the hydrated electron and hydroxyl radical and a decrease in the yields of molecular hydrogen and hydrogen peroxide with increasing temperature. These results are consistent with most of the experimental data. It is found that the best fit to the experimental data occurs when the radius of the initial spatial distribution of the hydrated electron is dependent on a process which scales according to an Arrhenius-like equation with an activation energy similar to that for electron movement between potential traps in water. The radii of the initial spatial distributions of all the other species appear to be independent of the temperature. The predictions of the model suggest that the initial radiation chemical yields of the reactive species are independent of temperature. An additional thermally dependent reaction for the decomposition of water is not required for the model predictions to match the experimental data. 47 refs., 8 figs., 1 tab.
Soft Skills among Students: A Case Study of UiTM Cawangan Kelantan

This article contributes to ongoing debates about soft skills among students. In 2017, the unemployment rate in Malaysia was at 3.42 percent as compared to 2.85 percent in 2014. Education system must aim towards employability and ensure quality in education to reduce the percentage of unemployment. Thus, this study aims to investigate the development of soft skills among students through co-curriculum activities in UiTM Cawangan Kelantan. The sample were 113 students from UiTM Cawangan Kelantan. Questionnaires adapted from previous research to measure the communication skill, problem solving skill, team building skill, leadership skill and soft development of soft skills among students through co-curriculum activities. SEM-PLS 3.0 were employed in this study. The findings revealed only team building skill has significant influence on developments of soft skills among students through co-curriculum activities. However, the study indicates that communication skill, problem solving skill and leadership skill are not significant towards development of soft skills among students through cocurriculum activities.
The Shape of the Transpiration Reduction Function under Plant Water Stress

Assuming transpiration to be reduced after a critical pressure head (usually chosen as −1.5 MPa or −150 m) at the root surface has been reached, transpiration rates in this so‐called falling‐rate phase were analyzed numerically for soils described by the van Genuchten–Mualem equations (numerical soils). The analysis was based on the differential equation describing radial flow to a single root. Numerically, the system was simulated by an implicit scheme. It is shown that, at limiting hydraulic conditions, relative transpiration (ratio between actual and potential transpiration) is equal to relative matric flux potential (ratio between actual matric flux potential and matric flux potential at the onset of limiting hydraulic conditions). Given this equality, transpiration reduction functions as a function of soil water content and as a function of time are presented for five types of analytical soils: a constant diffusivity, Green and Ampt, Brooks and Corey, versatile nonlinear, and exponential soil. While in the case of constant diffusivity, relative transpiration decreases as a linear function of water content, for the remaining four cases the decrease is a concave function of soil water content. Numerical simulations also result in a concave shape, unless the difference between water content at the onset of limiting hydraulic conditions and at permanent wilting is very small, for example, at high root densities. These discrepancies may be explained by the relative importance of a transition period between the constant‐ and falling‐rate phases.
Impact of molecular size on electron spin relaxation rates of nitroxyl radicals in glassy solvents between 100 and 300 K

Electron spin lattice relaxation rates were measured for 12 nitroxyls with molecular weights between 144 and 438, and for galvinoxyl, 1,3-bisdiphenylene-2-phenylallyl (BDPA), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) in glassy sucrose octaacetate. Relaxation rates for polar nitroxyls also were measured in glassy sorbitol. Dependence on T where V eff is effective molecular volume and γ is a material-specific parameter, was used to compare processes. Values of V eff were determined based on molecular libration in glassy sucrose octaacetate (γ = 3.5), tumbling in viscous decalin at 233 K (γ = 4.7), or tumbling in heavy mineral oil (γ = 6.0). For nitroxyl relaxation there is a master curve: log(1/T 1) vs log( T) (γ = 0.89). The similarity of the values of γ for the Raman process and for the additional process that contributes at higher temperatures, and the absence of frequency dependence between X- and Q-band, support assignment of this additional process as a local mode. For these radicals the contributions from the local mode and the Raman process are correlated and follow trends in spin–orbit coupling. The temperature dependence of spin echo dephasing in sucrose octaacetate is dominated by rotation of methyl groups and by a motional process analogous to the Raman process.
Acetylene cyclotrimerization on supported size-selected Pd-n clusters (1 <= n <= 30): one atom is enough!

We studied the cyclotrimerization of acetylene on size-selected Pdn clusters (1 ≤ n ≤ 30) supported on thin MgO(100) films by thermal desorption and Fourier transform infrared spectroscopy. Surprisingly, the production of benzene is already observed on a single palladium atom at low temperature (300 K). Using density functional theory (DFT) calculations we show that free inert Pd atoms are activated by charge transfer from defect sites of the MgO substrate upon deposition. For larger clusters (7 ≤ n ≤ 30) benzene is additionally produced at a temperature of 430 K and our results suggest the existence of a critical ensemble of seven palladium atoms for this high-temperature reaction mechanism.
An experimental investigation of the effects of axial divergence on diffraction line profiles

An experimental investigation has been carried out to determine the extent to which axial divergence in a conventional powder diffractometer influences the measurement of peak profile parameters. A Siemens D5000 θ–2θ diffractometer was used for this study along with the LaB6 line profile standard SRM 660. Eight unique levels of axial divergence were investigated either by removing one or more of the Soller slits, or by introducing different combinations of Soller slits in the incident and diffracted beams. The measure of axial divergence used throughout is based on the maximum axial divergences of the incident and diffracted beams, Ψi and Ψd. Axial divergence produces a small and almost constant shift δ2θp in the peak angle which in a typical diffractometer would amount to a zero offset 2θ≈0.005°. The integrated intensity of a profile increases almost linearly with the product Ψi*Ψd. The increase in breadth in profiles in the angular region 2θ<120° arises mainly from the change in asymmetry DH=Hlo−Hhi in which one side of the profile broadens (i.e., either the high angle or low angle side) without any significant broadening of the other side. Moreover, the asymmetry DH is linearly dependent on 2θ for a fixed level of axial divergence, and linearly dependent on the total axial divergence Ψi+Ψd at fixed 2θ.
Survey of Mycorrhizal Colonization in Native, Open-Pollinated, and Introduced Hybrid Maize in Villages of Chiquimula, Guatemala

ABSTRACT Replacing native plant types with introduced cultivars may have unexpected cropping system consequences. Native species and introduced cultivars may vary in their ability to form mycorrhizal symbioses with soil fungi and consequently affect phosphorus (P) nutrition. Low-input cropping systems often depend on mycorrhiza for adequate nutrition and growth, while high-input systems minimize the benefit of and need for colonization. Studies in wheat (Triticum aestivum L.) suggest that improving cultivars reduced the ability to form mycorrhiza. This study was conducted at six sites in the province of Chiquimula, Guatemala, to determine the difference in mycorrhizal infection rates between two maize (Zea mays L.) cultivars—‘Cushpeño,’ a native, open-pollinated variety, and ‘HB-83,’ an introduced, improved hybrid. The ‘HB-83’ was colonized at a significantly lower percentage (67%) than was ‘Cushpeño’ (72%; α = 0.0137). A strong negative correlation (r = −0.953) existed between Mehlich-3 extractable soil P and differences in mycorrhizal colonization rates between the two genotypes. The full impact of lower colonization rates of the introduced hybrid on sustainability of the village agricultural system needs further investigation.