Miracle-dz/UniFAR-FTUs huggingface dataset:
Rapid biomimetic mineralization of chitosan scaffolds with a precursor sacrificed method in ethanol/water mixed solution

Biomimetic mineralization was performed on a large scale by a rapid and efficient approach. Chitosan scaffolds were placed in a mixed solution of urea, ethanol and distilled water, followed by the introduction of dibasic sodium phos- phate (0.1M) and calcium chloride (0.1M) with the molar ratio of 1.67. These mixed solvents was then adjusted to weakly alkaline by adding sodium hydroxide solution. Finally the reaction mixture was sealed and kept at 80oC for predetermined time. The composition and morphology of the apatite and the hybrid scaffolds were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier Transform Infrared spectroscopy (FTIR) and environmental scanning electron microscopy (ESEM). The mechanism of nucleation and growth of crystals was discussed as well. The results revealed that chitosan scaffolds improved the crystallinity of hydroxyapatite (HAP) crystals. With the extension of mineralization time, the mineral layers on the outer surface and inner section of chitosan scaffolds increased as well. Fur- thermore, the compressive strength and modulus of the HAP-chitosan scaffolds biocomposites increased to 0.55±0.003 and 29.29±1.25 MPa respectively. Such one-pot approach may be extended to the mineralization of other materials and will have a broad application in the future.
Significance of bound residual water in the DMSO solution structure of stable peptide hydrates

Water molecules in peptide hydrates are widely known to be directly involved in the stabilization of the peptide structure in the solid state. In this work, the influence of tightly bound residual water molecules on the conformational properties of two hydrates of the L-Arg-L-Leu-Gly and Gly-L-Phe-L-Leu peptide lyophilized from water at acidic pH, has been investigated for the first time in DMSO solution by means of 1 D and 2D 1H NMR spectroscopy. Significant conformational changes have been observed in solution as the bound residual water is gradually expelled from the peptide hydrate. These observations point out the crucial role of bound water in fine-structural determinations of peptides in solution when evaluating NMR data.
THE INFLUENCE OF FUEL TYPE ON PARTICLE EMISSIONS IN COMBUSTION OF BIOMASS PELLETS

ABSTRACT Three different biomass fuels (bark pellets, wood pellets and granulates made from hydrolysis residues) were burned under identical conditions to determine the effect of biomass type on the amount and composition of the combustion-generated particles under fixed-bed conditions. Significant differences in emissions of dust, submicron particles, and the shape of the particle number and mass size distributions were found between the different biomass fuels. For the particles that were dominated by ash elements, the particle emissions were correlated to the ash concentration in the unburned fuel. However, if the combustion condition allowed for organic particles, the “sooting” tendency of the fuel was found to become more important than the amount of ash in the fuel. Furthermore, the fuel type affects the particle emissions more than changes in reactor operating parameters.
Chitosan and hydroxyapatite composite cross‐linked by dopamine has improved anisotropic hydroxyapatite growth and wet mechanical properties

Three of the major impediments to using hydroxyapatite (HAp)‐collagen composites for hard tissue repair are the difficulties in anisotropic growth of HAp, in functional collagen production, and in their cross‐linking. To solve these problems, we fabricated HAp‐based composites for hard tissue repair by using chitosan as a collagen matrix substitute, and dopamine as a replacement for aldehyde‐based cross‐linkers. In the presence of chitosan and dopamine, the HAp particles grew anisotropically in a needle shape with an aspect ratio of ∼4.4. The needle‐shaped HAp particles were dispersed well in the chitosan matrix, and dopamine‐mediated cross‐linking enhanced the stiffness and reduced swelling in the presence of water. The composite is too weak for use in hard tissue repair, but could be used for curing dentin sensitivity by blocking and remineralization on dentinal tubules, and in drug‐delivery applications.
Electronic Structure of Tetrahydropteridine Derivatives

Summary Recently; the 4-amino analogue of tetrahydrobiopterin was found to be a strong inhibitor of nitric oxide synthase while being bound to the enzyme in a manner similar to the natural cofactor tetrahydrobiopterin. We were interested in the electronic properties of these and similar compounds and studied therefore the following model tetrahydropteridine structures: tetrahydrolumazine, tetrahydropterin, 4-amino-analogue of tetrahydropterin and N5-methyl-tetrahydropterin. Ab initio quantum chemical computations used the Hartree- Fode method with basis set 6-31G** after geometry optimization with basis set 3-21G*. Results reveal dramatic differences in distribution of electronic charge and all the molecular properties derived thereof~ between a) the lumazine system, b) the normal pterin system, and c) the 4-amino analogue. In contrast, differences of electronic properties between tetrahydropterin and its N5-methyl-derivative are negligible. Our results are compatible with recent speculations that the striking differences between the effects of the tetrahydropterin struculrc and its 4-amino analogue on cnznllatic activity may be due to electronic interaction between the pyrimidine moiety of the ptcrin ring systcm and the heme group.
POLARIZATION VARIATIONS DUE TO DISLOCATION CONFIGURATIONS IN HETEROEPITAXIAL FERROELECTRIC LAYERS

ABSTRACT Dislocation networks in epitaxial ferroelectric thin films consist of misfit and threading dislocations. They usually form at high temperatures during film growth when the film is paraelectric. Once the film becomes ferroelectric upon cooling, they induce spatial polarization gradients which are detrimental to the desired properties. This study analyzes the ways in which they affect the ferroelectric properties. A qualitative comparison is made using thermodynamic and electrostatic analysis concluding that the misfit segments of dislocations are more detrimental than the threading segments.
Heat and momentum transport characteristics of non‐Newtonian aqueous thorium oxide suspensions

Heat-transfer and pressure-drop measurements were made with non- Newtonian aqueous theorium oxide suspensions. A comparison of the results of the two different kinds of measurement allowed thee general features of nonNewtonian thorium oxide suspension heat transfer to be readily identified, thus leading to a clear understanding of anomalies observed in jkprevious suspension heat- transfer studies. Data were obtained at suspension concentrations up to 0.10 volume fraction solids, (1,000 g. of thorium/kg. of water) in systems having tube diameters of 0.318 and 1.030 in. In addition laminar-flow data were taken with a capillary-tube viscometer with a tube diameter of 1/8 in. and an L/D of 1,000. It was shown that laminar flow physical properties determined with the 1/ 8 in. diameter tube were satisfactory for correlating data taken with tubes up to 1.030 in. in diameter. Until the present study, information was not available which would permit a choice between two different viscosities for use in correlating nonNewtonian turbulent heat transfer and flow data. The limiting viscosity at very high shear rates is shown to give a unique correlation of turbulent data for tube diameters from 0.124 to 1.030 in. , whereas the use of the effective viscosity at very high shearmore » rates is shown to value of the wall shear stress corresponding to each given flow condition) gives a pronounced diameter effect in turbulent-flow correlations. The data show that the onset of turbulence for both the pressure-drop and heat-transfer measurements occurs at the same Reynolds number and is approximated by the value predicted by the Hedstrom criterion (II). The heat-transfer transition region extends to Reynolds numbers a factor of four times greater than the critical, as is also the case with Newtonian materials. Heat transfer to thorium oxide slurries in fully developed turbulent flow is the same as that predicted by the usual correlations for Newtonian fludds to within the precision of the experimental data, provided that the Reynolds and Prandtl numbers are calculated with the limiting viscosity at high rates of shear, , for this viscosity. An approximate form of Martinelli's momentum heat transfer analogy correlates the experimental results within +17 and -36%. (auth)« less
Scrutinizing Gypsum Board Thermal Performance at Dehydration Temperatures

This article investigates the thermal performance of gypsum boards in the dehydration temperature region, where pronounced chemical reactivity is anticipated. Gypsum board samples were gradually heated up to 300°C, using a low heating rate. Temperature measurements at pre-selected board locations indicated three distinct stages of gypsum dehydration; free moisture evaporation, transformation of calcium sulfate dihydrate to calcium sulfate hemi-hydrate and of calcium sulfate hemi-hydrate to calcium sulfate anhydrate. Physical properties of the gypsum board sample, that is density, specific heat, and thermal conductivity, were measured as a function of the dehydration temperature range. Results suggested that the thermal conductivity of the calcium anhydrate sulfate is higher than that of the hemi-hydrate, despite the fact that gypsum porosity increases during the dehydration process. Based on the experimental results, correlations for the thermal conductivity and the dehydration energy as a function of the mass loss during the dehydration process and the initial water content of the gypsum board, respectively, were obtained.
Study on the effect of heat treatment and gasification on the carbon structure of coal chars and metallurgical cokes using fourier transform Raman spectroscopy

Differences in the development of carbon structures between coal chars and metallurgical cokes during high-temperature reactions have been investigated using Raman spectroscopy. These differences are important for differentiation between different types of carbons present in the dust recovered from the top gas of the blast furnace. Coal chars have been prepared from a typical injectant coal under different heat-treatment conditions. These chars reflected the effect of peak temperature (from 900 to 2400 °C), residence time at peak temperature (from 2 s to 1 h), heating rate (from 1 to 6000 K/s), and pressure (from 3 to 40 bara) on the evolution of their carbon structures. The independent effect of gasification on the development of the carbon structure of a representative coal char has also been studied. A similar investigation has also been carried out to study the effect of heat-treatment temperature (from 1300 to 2000 °C) and gasification on the carbon structure of a typical metallurgical coke. Two Rama.
NUMERICAL SIMULATIONS OF TRANSIENT INTERFACIAL PHENOMENA IN MISCIBLE FLUIDS

To study theoretically interfacial (capillary) phenomena in miscible fluids, we consider a continuous medium with a composition gradient. We describe it with the model consisting of the heat and diffusion equations with convective terms and of the Navier-Stokes equations with an additional volume force written in the form of the Korteweg stresses arising from nonlocal interaction in the fluid. It is proportional to the square of the composition gradient with the proportionality coefficient depending on temperature. We carry out numerical simulations of this model and show that the capillary force can cause convection in the initially quiescent liquid. For physically realistic values of parameters the liquid motion, though decreasing rapidly in time, can probably be observed experimentally. The proportionality coefficient, k, is the same square gradient parameter in the Cahn-Hilliard theory for diffuse interfaces and for phase separation. We estimate it on the basis of measurements from spinning drop tensiometry and light scattering for two systems: poly(dodecyl acrylate)/dodecyl acrylate and glycerin/water. Because concentration and temperature gradients also cause buoyancy-induced convection, experiments must be performed in weightlessnes s. Therefore, long term, high quality weightlessness is required to test the predictions of the modeling, and we propose a photopolymerization system to create the concentration and temperature gradients. Transient Interfacial Phenomena in Miscible Polymer Systems (TIPMPS) and a Microgravity Science Glovebox experiment, Miscible Drop in Microgravity (MDMG) are both planned for the International Space Station.
Characterization of explosives by liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry using electrospray ionization and parent‐ion scanning techniques

Analytical techniques for the detection of small amounts of explosives (in the picogram range) are now involved in various application. Some of them concern soil, water and air monitoring in order to face environmental problems related to improper handling procedures either in stocking or in wasting of the explosive products. Other areas are strictly related to forensic analysis of samples coming either from explosion areas where the matrix is various (metal, glass, wood, scraps), or from explosives transportation related to international terrorism. Generally speaking, for these applications the bulk of the matrix seriously interferes in the detection of the explosive analyte, which is usually present at trace levels. Unfortunately, despite some improvements, analytical techniques developed up today in this domain are still faced to two main constraints: the introduction of new products with unanticipated chemico-physical properties and the requirement of a routine and fast analytical method which can handle any matrix with a minimal clean-up and performing a sensitivity compatible either with the ever-decreasing demanded detection limit and with the ever-decreasing available specimen amount. These requirements can be fulfilled now by the new LC-MS and LC-MSMS techniques: mass spectrometry (MS) is likely an universal detector but even specific, especially when implemented in tandem MS (MSMS); LC is by far the most suitable technique to handle such a kind of compounds. Moreover, of a particular concern are some explosives which are reported to be thermally stable but difficult to dissolve. Some of the experiments on characterization of explosives [Octagen (HMX), Ethyleneglycol dinitrate (EGDN), Exogen (RDX), Propanetriol trinitrate (NG), Trinitrotoluene (TNT), N-Methyl-N-tetranitrobenzenamine (TETRYL), Dintrotoluene (DNT), Bis-(nitrooxy-methyl) propanediol dinitrate (PETN), Hexanitrostilbene (HNS), Triazido-trinitrobenzene (TNTAB), Tetranitro-acridone (TENAC), Hexa-nitrodiphenylamine (HEXYL), Nitroguanidine (NQ)] by LC-MS and LC-MSMS with the API-IonSpray source and using the Parent-Scan technique are presented.
Positron annihilation studies on the nature and thermal behaviour of irradiation induced defects in tungsten

Positron Annihilation Lifetime Spectroscopy has been performed with a pulsed positron beam to investigate the nature and evolution of implantation-induced defects created in the track region (TR) of 800 keV 3He ions at different fluences. At high fluence - 5×1016 cm–2 - lifetime decomposition exhibits a predominant (98%) positron lifetime of 200 ps which is attributed to irradiation induced monovacancy. The increasing average lifetime as a function of the post-implantation annealing temperature has allowed to identify vacancy clustering due to vacancy migration (that occurs from 473 K). (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Calidad microbiológica del agua obtenida por condensación de la atmósfera en Tlaxcala, Hidalgo y Ciudad de México

La disponibilidad de agua potable en cantidad y calidad, es un problema grave en el mundo. Hoy en dia existen tecnicas para obtener agua del aire y mitigar esta situacion. Sin embargo, conocer la calidad microbiologica del agua proveniente de la atmosfera resulta relevante, debido al riesgo asociado con la ingesta de agua contaminada con bacterias provenientes de las heces de humanos y animales. No obstante, el diagnostico de estos microorganismos, requiere de laboratorios especializados y representa varios dias de analisis y costos elevados. El objetivo de esta investigacion consistio en evaluar la cantidad de colonias de coliformes totales y fecales encontradas en el agua atmosferica condensada utilizando pruebas rapidas. El estudio se realizo en tres zonas: San Felipe Hidalgo, Tlaxcala; Huichapan, Hidalgo y en la Ciudad de Mexico. En cada sitio se tomaron 9 muestras diurnas y 9 nocturnas con tres repeticiones, en dos epocas del ano (agosto-septiembre, 2011) y (diciembre-enero 2011-2012). El agua se capto con el prototipo de un aparato denominado higroiman, el cual disminuye la temperatura de la superficie de contacto con el ambiente para inducir el punto de rocio y condensar la humedad de la atmosfera. Se aplico una prueba de medias (Tukey, P ≤ 0.05) a los resultados obtenidos y se compararon con los limites permisibles de agua potable de acuerdo con la OMS. La ciudad de Mexico presento la mayor cantidad de colonias de coliformes totales y Escherichia coli en los dos muestreos. Mientras que Huichapan, Hidalgo presento la menor cantidad de coliformes totales y fecales. El agua atmosferica en los tres sitios mencionados no se considera potable sin previo tratamiento.
Anti-diabetic effects of total flavonoids from Polygonatum Sibiricum Red in induced diabetic mice and induced diabetic rats

Polygonatum sibiricum (Red)，well-known Chinese traditional medicine ，is widely used for treatment of diverse diseases. In our study, Total flavonids of Polygonatum sibiricum (Red) (TFP) were obtained with extraction from Polygonatum sibiricum Red by 70% ethanol and purified with macroreticular resin. The experiments were designed to detect the anti-diabetic activity of TFP By determination of blood glucose (BG) with one touch gluco-meter and insulin levels by using a radioimmunoassay kit in streptozotocin (STZ) induced diabetic mice and alloxan induced diabetic rats and alpha-amylase inhibitory activity by Alpha-amylase inhibition assay in vitro . In this study,TFP had beneficial effects on the improvement in the control of blood glucose. Daily administration with 50–200mg/kg body weight of TFP for nine day’s can reduce hyperglycemia in STZ induced diabetic mice. Thirtieth day’s administration with TFP (50–200mg/kg body weight) also lowered significantly fasting blood glucose in alloxan induced diabetic rats. The hypoglycemic effects of TFP at 50 and 100 mg/kg is less than and at 200mg/kg is similar to that of Acarbose 20 mg/kg and Gliclazide 15 mg/kg. TFP also can increase significantly the insulin level in alloxan-induced type 2 diabetic rats ( P<0.05) with compared the control. Alpha-amylase inhibition assay in vitro showed that TFP inhibited significantly alpha-amylase activity in a dosage-dependent manner. According to our results, TFP possess significant and dosage-dependently anti-diabetic activity. TFP is the primary hypoglycemic active compounds or one of the hypoglycemic active compounds of Polygonatum sibiricum Red that would merit further studying and developing this traditional medicinal herb.
Soil colour: its measurement and its designation in models of uniform colour space

SUMMARY The principles of colour perception are outlined and applied to the problems of soil colour measurement using ‘Munsell Soil Color Charts’. As care is needed in using these charts to make an accurate assessment of soil colour, recommendations for the correct methods for soil colour measurement are outlined. The three soil colour characteristics of Munsell Hue, Value and Chroma are commonly used in multivariate analyses as orthogonal, equi-dimensional, linear variables that describe perceived colour space. Such an approach may be inappropriate because the angular separation of Hue and an approximately 2.5:1 scaling relationship between Value and Chroma should be accounted for in any model of perceived colour space. An appropriate and simple polar transformation of Munsell colour data is compared with some other coordinate systems for representing colour space, including the CIELAB system. This polar transformation is recommended for processing colour data in multivariate analyses.
Functionalization of carbon nanotubes via 1,3-dipolar cycloadditions

The organic functionalization of carbon nanotubes has opened new avenues with opportunities to fabricate novel nanostructures by improving both their solubility and processibility. The 1,3-dipolar cycloaddition of azomethine ylides onto carbon nanotube (CNT) networks may play a relevant role towards this direction. CNT-based materials have been synthesized possessing differently functionalized solubilizing chains and hold strong promise as useful building blocks for the construction of novel hybrids for nano- and bio-technological applications.
Nutrient concentrations and acidity in ferralitic soil under perennial cropping, fallow and primary forest in central Amazonia

The long‐term productivity on the acidic, nutrient‐poor upland soils of central Amazonia depends to a large extent on the chemical soil fertility as influenced by vegetation type and management. We compared soil and soil solution data from permanent cropping, fallow and primary forest on a Xanthic Ferralsol in central Amazonia to evaluate changes of soil fertility following forest conversion, agricultural use at different intensities and setting aside agricultural land. The agricultural systems included a perennial polyculture at two fertilizer inputs and a monoculture plantation. Soil and soil solution were collected to 2 m depth, and the soil solution was monitored over 2 years. Both soil and soil solution data showed decreasing soil fertility in the sequence: monoculture and polyculture at large input, polyculture at small input, forest and fallow. The soil solution data were more sensitive to effects of systems and fertilizer inputs on subsoil fertility. Fractionation of the N in the soil solution showed a larger proportion of dissolved organic N in the N‐poor fallow soil than in the soil under forest and agriculture. The soil under fallow, forest and low‐input agriculture had larger exchangeable acidity than that under high‐input agriculture, but the Al concentrations in the soil solution were very small because there were few cations with which to exchange and less nitrification. In high‐input agriculture, pronounced acidification peaks in the topsoil solution followed fertilization. The comparison of soil and soil solution data explained why the spontaneous vegetation thrives at very large exchangeable acidity in these soils, whereas agricultural systems often depend on liming to reduce the concentration of toxic Al in the soil.