Miracle-dz/UniFAR-FTUs huggingface dataset:
The structure of vitreous boron oxide

A new study of the structure of vitreous boron oxide has been made under greatly improved conditions. Using Rh Kα radiation with the method of fluorescence excitation, reliable intensity values were measured to 4πsinθ/λ = 20 A−1, and a rigorous interpretation was obtained in terms of pair functions. Each boron is triangularly surrounded by 3 oxygen atoms with a B–O distance of 1.37 A. Each oxygen atom is bonded to 2 boron atoms. The major part of the glass is made up of boroxol groups B3O6 (a hexagonal ring of 3 boron atoms and 3 oxygen atoms with 3 corner oxygen atoms outside the ring). These groups are linked together by sharing the corner oxygen atoms, with randomness in orientation about the B–O bond directions at the shared oxygen atoms. Within the ring the B–O–B angle is 120° and at the shared oxygen it is approximately 130°. There is satisfactory agreement between the calculated and measured pair function distribution curves. In vitreous B2O3 the scheme of bonding does not fill space, and any boroxol group has neighboring groups which are not directly connected to it by B–O and O–B bonds. The measured pair function areas indicate neutral atoms, so that the bonding is predominantly covalent.
Effect of p‐toluenesulfonate on inhibition of overoxidation of polypyrrole

Electrochemically synthesized polypyrrole (PPy) films degrade under anodic polarization in aqueous solution. PPy is irreversibly oxidized leading to subsequently to an insulating material. This article highlights the degradation behavior of electrochemically synthesized PPy films using inorganic (perchlorate, ClO4−), organic (p-toluenesulfonate, pTS−) and mixed (inorganic-organic, ClO4− + pTS−) anions systems in aqueous solution. The PPy films were subject to overoxidation by means of anodic polarization for a certain period of time and consecutively cyclic voltammetry and electrochemical impedance spectroscopy were employed to investigate the influence of anions used during polymerization on the stability and redox activity of the polymer. The modification in the surface morphology of PPy films due to the application of anodic polarization distinctively shows the effect of degradation at polymer/electrolyte interface. The presence of organic anion in the system (PPy/pTS and PPy/mixed) has shown improved electrochemical activity and is stable to electrochemical degradation for a longer period of time than PPy/ClO4−. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Study of oxidative stress in different clinical severities of acne vulgaris

Background Acne vulgaris is a multifactorial disease, but recent studies have focused on the role of oxygen free radicals and antioxidant enzymes. Malondialdehyde (MDA) is the end product of lipid peroxidation and is a good marker of free radical-mediated damage and oxidative stress. Superoxide dismutase (SOD) represents the major cellular defense against superoxide anions. Objective The objective of this study was to study the role of oxidative stress in acne vulgaris and to detect a possible link with the different clinical severities. Patients and methods Fifty patients with acne vulgaris and 20 healthy controls were included in this study. The severity of the disease was assessed using the Global Acne Grading System. The levels of SOD in erythrocytes and MDA in plasma were measured using a spectrophotometer. Results Although higher SOD levels and mean values were present in patients, there was no statistically significant difference compared with the controls. MDA levels showed a significant difference between patients and controls (P < 0.05), with MDA being higher in patients, indicating a condition of oxidative stress that had resulted from a high level of lipid peroxidation in acne patients. Comparison of SOD levels in patients showed that patients with severe acne had the lowest levels in comparison with patients with mild and moderate acne (P < 0.001). SOD levels were the highest in patients with mild acne. In terms of MDA levels, patients with severe acne showed the highest plasma MDA levels compared with those with mild and moderate (P < 0.05) acne, suggesting an increase in reactive oxygen species production overwhelming the antioxidant capacity. The lowest MDA levels were observed in mild acne. Conclusion Oxidative stress may play a role in the etiopathogenesis of acne and⁄or the progression of the disease. Coadministration of antioxidant drugs with various lines of treatment of acne might be helpful, especially for those with inflammatory lesions.
Dry Etching of Deep Si Trenches for Released Resonators in a Cl2 Plasma

An electron cyclotron resonance source has been used to generate a Cl 2 plasma and etch Si trenches >100 μm deep. High microwave power was used to achieve Si etch rates of 1.09 μm/min for trench openings >500 μm. With pressure ranging from 2 to 30 mTorr, etching at higher pressures, up to 20 mTorr, increased the anisotropy of the etch, due to sidewall passivation. In addition, Si etch rates were faster at high pressures, increasing from 0.47 to 0.78 μm/min as the pressure was increased from 2 to 30 mTorr. Features with aspect ratios >30 have been fabricated using 1200 W microwave power and 50 W radio-frequency power at 20 mTorr with 20 sccm of Cl 2 flow. Under these conditions,the self-induced dc bias at the stage was 50 V, and a selectivity >250 over an evaporated Ni mask was achieved. This allowed the use of an evaporated Ni mask for trench depths >50 μm. Electroplated Ni could be used as an etch mask, and the selectivity of Si over Ni was 75. Also, the addition of SF 6 increased the etch rate to as high as 1.89 μm/min for trench openings >500 μm, while keeping the vertical profile and smooth surface. The Si etch rate was found to depend on the aspect ratio and an etch rate reduction of 18% was seen in the Cl 2 plasma for 1.5 μm wide trench openings relative to the etch rate of a 50 μm wide trench opening. The etch rate also increased as the etch time increased. For a 30 min etch in the Cl 2 plasma, an etch rate of 0.79 μm/min was measured; however, for a 2 h etch, an etch rate of 1.00 μm/min was measured.
Surface and Interfacial Tension of Cellulose Suspensions

Surface (air−fluid) and interfacial (fluid−fluid) tensions of coexisting isotropic and anisotropic aqueous suspensions of microcrystalline cellulose have been investigated as a function of suspension concentration and ionic strength using the pendant drop method. The surface tension of the individual phases remained constant as concentration was varied within the biphasic region, where the anisotropic surface tension value fluctuated around 72 mN m-1 (value for pure water) and the cellulose chains in the isotropic phase displayed surface activity as surface tension was ca. 67 mN m-1. Ionic strength influenced surface characteristics as the surface tension of both phases increases systematically with addition of HCl. Such changes in surface activity are attributed to variations in surface packing density and distribution of the hydrophilic and hydrophobic segments of the cellulose chains. The interfacial tension measurement contrasts such behavior as it remained constant at ca. 10-2 mN m-1 as a function of.
Synthesis and characterization of poly(methyl methacrylate)/casein nanoparticles with a well‐defined core‐shell structure

Well-defined, core-shell poly(methyl methacrylate) (PMMA)/casein nanoparticles, ranging from 80 to 130 nm in diameter, were prepared via a direct graft copolymerization of methyl methacrylate (MMA) from casein. The polymerization was induced by a small amount of alkyl hydroperoxide (ROOH) in water at 80 °C. Free radicals on the amino groups of casein and alkoxy radicals were generated concurrently, which initiated the graft copolymerization and homopolymerization of MMA, respectively. The presence of casein micelles promoted the emulsion polymerization of the monomer and provided particle stability. The conversion and grafting efficiency of the monomer strongly depended on the type of radical initiator, ROOH concentration, casein to MMA ratio, and reaction temperature. The graft copolymers and homopolymer of PMMA were isolated and characterized with Fourier transform infrared spectroscopy and differential scanning calorimetry. The molecular weight determination of both the grafted and homopolymer of PMMA suggested that the graft copolymerization and homopolymerization of MMA proceeded at a similar rate. The transmission electron microscopic image of the nanoparticles clearly showed a well-defined core-shell morphology, where PMMA cores were coated with casein shells. The casein shells were further confirmed with a zeta-potential measurement. Finally, this synthetic method allowed us to prepare PMMA/casein nanoparticles with a solid content of up to 31%. Thus, our new process is commercially viable.
Parboiled rice: A study about attitude, consumer liking and consumption in São Paulo, Brazil

The consumption of parboiled rice in Brazil is low when compared to milled rice, despite alleged nutritional, convenience and technological benefits. Data collected through a survey with 186 consumers in the city of S˜ ao Paulo, Brazil, were analysed with the aim of gaining a better understanding of local consumer attitudes towards parboiled rice. Six attitudinal items were assessed as giving a score on a five-point Likert scale. Cluster analysis was used to identify three segments of respondents with different attitudinal patterns. Subsequently, correspondence analysis revealed associations among clusters and educational level and liking/consumption data. Most consumers did not show an established opinion about the main characteristics of parboiled which indicates a weakness of the product promotion. A positive attitude, as demonstrated by a higher intake of parboiled rice, was a reflection of habit and liking, while a negative attitude seemed to be due to previous negative experience and misconceptions about the product.  2007 Society of Chemical Industry
Functionalization of Carbohydrates in Water

Carbohydrate chemistry and chemistry in water go well with each other for three main reasons. First, the synthesis of carbohydrate derivatives of biological relevance has profited from the advances in the use of aqueous media as solvents, leading to new compounds with improved reactivity and selectivity. Second, carbohydrates, being water soluble, have been used as water solubility inducers for water-promoted reactions. Third, part of the chemistry devoted to the use of carbohydrates as raw materials, as an alternative to fossil resources, is performed in water. Indeed, it is now strategic to combine different key principles of green chemistry, namely the use of clean solvents and the use of renewable starting materials in synthetic chemistry. Moreover, it can be connected with the design of new derivatives with improved environmental properties. The chapter focuses on the chemistry of small carbohydrates (not polysaccharides), reviewing CC bond formation reactions involved in multi-step syntheses of complex structures or in direct processes towards functional derivatives, CN and CO bond formation reactions. The latter aspect, which deals with the reactivity of sugars as polyols, is an extremely large topic, and for reasons of conciseness the main issues of this chemistry will be illustrated by focusing on the example of sucrose, the most available small carbohydrate. Also, some approaches in which a carbohydrate serves as a polar appendage which provides the water solubility necessary to take advantage of hydrophobic effects are described, in addition to the use of aqueous solutions of sugars as media in which hydrophobic effects are intensified. Keywords: carbohydrates; water; functionalization; C-glycosides; renewable resources; sucrose; green chemistry
Wood Cellulose Preparation Methods and Mass Spectrometric Analyses of δ13C, δ18O, and Nonexchangeable δ2H Values in Cellulose, Sugar, and Starch: An Interlaboratory Comparison

Interlaboratory comparisons involving nine European stable isotope laboratories have shown that the routine methods of cellulose preparation resulted in data that generally agreed within the precision of the isotope ratio mass spectrometry (IRMS) method used: ±0.2‰ for carbon and ±0.3‰ for oxygen. For carbon, the results suggest that holocellulose is enriched up to 0.39‰ in 13C relative to the purified α-cellulose. The comparisons of IRMS measurements of carbon on cellulose, sugars, and starches showed low deviations from −0.23 to +0.23‰ between laboratories. For oxygen, IRMS measurements varied between means from −0.39 to 0.58‰, −0.89 to 0.42‰, and −1.30 to 1.16‰ for celluloses, sugars, and starches, respectively. This can be explained by different effects arising from the use of low- or high-temperature pyrolysis and by the variation between laboratories in the procedures used for drying and storage of samples. The results of analyses of nonexchangeable hydrogen are very similar in means with standard .
New Extended Compound Lifetime Distributions

Proposing flexible generalized families and/or models is the recent demand in modern distribution theory. Compounding is the preferred way of generalizing an existing distribution by mixing distributions of the interest, that is possible only through mixing discrete with continuous, continuous with continuous and inducting the CDF of one distribution into the CDF of the other. In this thesis, five new generalize families (or distributions) are introduced. Firstly, the Poisson Weibull-X family is introduced. Its general mathematical properties are obtained and a special model, Poisson Weibull-Pareto, is studied. Secondly, a new logistic generalized family is proposed, and the properties of its special model, the logistic exponential, are obtained. Thirdly, the Poisson Nadarajah-Haghighi model is proposed and its properties are investigated in detail. Fourthly, a new flexible model, the MarshallOlkin logistic exponential is introduced and studied. Finally, the fifth generalized model, the Lindley negative-binomial, is developed and its statistical properties are obtained. As a whole in this thesis, five new flexible models and their properties are obtained such as reliability properties, quantile function, shapes of the density and hazard rate, moments, mean deviations, Lorenz and Bonferroni curve, Shannons entropy and order statistics. The maximum likelihood method is used for the parameter estimation of these new models. Simulation studies are also carried out to evaluate the performance of the maximum likelihood estimation. Several real-life data sets are used to illustrate the applicability of the proposed models.
High-performance vertical hydrogen sensors using Pd-coated rough Si nanowires

We fabricated Pd-coated rough Si nanowires, using a combination of Si electroless etching and Pd sputtering. The semi-densely distributed, vertical-standing rough Si nanowires, which were clustered locally with inter-cluster distances of several nm to several μm, were selected as a basal platform. Pd was coated only on the upper part of the Si nanowires in the semi-dense configuration, and their surface profile replicated the surface morphology of Si nanowires. The Pd-coated rough Si nanowires showed good reversibility and excellent hydrogen-sensing performance in terms of sensitivity (>300%), response time (<3 s), and detection limit (∼5 ppm). These attributes are discussed in terms of the vertical-standing nanowire structures and the rough surface effect of the nanowires. Interestingly, the variation in sensitivity of the Pd-coated Si nanowire sensors was divided into two regimes, which appeared in the low and high hydrogen concentration ranges, respectively. A simple model is also provided to account for this unusual finding.
Raman Spectroscopy of Carbon Nanotubes in 1997 and 2007

Over the last 10 years, carbon nanotubes have offered a unique system for the study of Raman spectra in one-dimensional systems, and at the same time Raman spectroscopy has provided a widely used and powerful tool for the characterization of single walled carbon nanotubes (SWNTs). The 10 year history of Raman scattering in SWNTs is reviewed here and future prospects for the field are discussed.
Nitrogen-enriched ordered mesoporous carbons through direct pyrolysis in ammonia with enhanced capacitive performance

Self-assembly of phenolic resins and a Pluronic block copolymer via the soft-template method enables the formation of well-organized polymeric mesostructures, providing an easy way for preparation of ordered mesoporous carbons (OMCs). However, direct synthesis of OMCs with high nitrogen content remains a significant challenge due to the limited availability of nitrogen precursors capable of co-polymerizing with phenolic resins without deterioration of the order of mesostructural arrangement and significant diminishment of nitrogen content during carbonization. In this work, we demonstrate pyrolysis of the soft-templated polymeric composites in ammonia as a direct, facile way towards nitrogen-enriched OMCs (N-OMCs). This approach does not require any nitrogen-containing carbon precursors or post-treatment, but takes advantage of the preferential reaction and/or replacement of oxygen with nitrogen species, generated by decomposition of ammonia at elevated temperatures, in oxygen-rich polymers during pyrolysis. It combines carbonization, nitrogen functionalization, and activation into one simple process, generating N-OMCs with a uniform pore size, large surface area (up to 1400 m2 g−1), and high nitrogen content (up to 9.3 at%). More importantly, the ordering of the meso-structure is well-maintained as long as the heating temperature does not exceed 800 °C, above which (e.g., 850 °C) a slight structural degradation is observed. When being used as electrode materials for symmetric electric double layer capacitors, N-OMCs demonstrate enhanced capacitance (6.8 μF cm−2vs. 3.2 μF cm−2) and reduced ion diffusion resistance compared to the non-NH3-treated sample.
Vesicle-micelle structural transitions of phospholipid bilayers and sodium dodecyl sulfate

The transitional stages resulting in the interaction of sodium dodecyl sulfate (SDS)/phosphatidylcholine liposomes were studied by means of transmission electron microscopy (TEM), light scattering, and permeability changes. A linear correlation was observed between the surfactant/lipid molar ratio (Re) and the surfactant concentration throughout the process. However, the bilayer/aqueous phase partition coefficient (K) showed a maximum for 30% bilayer permeability (beginning of bilayer saturation). Hence, a preferential incorporation of surfactant molecules into liposomes governs the initial interaction steps, leading to the beginning of bilayer saturation with a free surfactant concentration that was lower than its critical micelle concentration (cmc). Additional surfactant amounts increased the free surfactant until the cmc is reached, after which solubilization started to occur. Large unilamellar vesicles began to form as the surfactant exceeded 10 mol % (20% permeability), the maximum vesicle growth being attained between 30 and 100% of permeability. A sharp decrease in static light scattering occurred after the Re for saturation (Re sat ), where TEM observations still showed vesicles although with traces of smaller structures. From 60 mol % the size curves began to show a bimodal distribution. TEM pictures for 60-68 mol % showed a gradual vesicle disintegration with formation of tubular structures. SDS concentrations greater than 74 mol % led to the solubilization of bilayers.
Seasonal variation of particulate mMatter mass concentration and content of metals

In this paper, an attempt is made to characterize PM10 imission field in the area of Warszawa with regard to PM content of the metals As, Cd, and Ni. Particulate matter concentration measurements were performed within this agglomeration with the use of many measuring methods, different not only in respect of the sampler operation rules, but also of the accuracy, sampling frequency, and separation of the particulate matter fractions. Since 1 October 2003, Warszawa agglomeration has had an extended measurement network consisting of 4 automatic stations and 7 manual ones. This paper attempts to estimate the influence of the prevailing meteorological conditions on PM10 imission and also to determine those parameter groups that enable the best description of monthly and seasonal variability of particulate matter. The data considered in this paper were collected in 2004-08. Based on the performed analysis, it could be concluded that air quality in the area of Warszawa agglomeration is still unsatisfactory. The main cause of high PM concentration in Warszawa is the dynamic development of vehicular traffic and ever-increasing number of cars; both factors cause the PM concentration to be several times higher. The second important source of particulate matter in the Warszawa area is so-called “low emission” , occurring in the heating season, generated mainly by the processes of combustion in the communal and housing sectors. In 2004-08 the meteorological conditions prevailed 22.4% to 76.2% of the decadal variability of PM concentration in the individual months and 9.5% to 56.8% of seasonal variability. The most significant influence of the meteorological conditions was during the winter, especially in January. The regression analysis has found evidence for statistically vital relationships of PM10 concentration and meteorological parameters, especially maximum air temperature, wind speed, and precipitation. Research on the chemical composition of PMs presented in this paper confirms that the target values of arsenic, cadmium, and nickel concentration in PM10, determined by Directive 2004/107/WE, were not exceeded at the network stations in 2006-08 and the recorded concentration of these heavy metals were low. Analyzing the tendency of air quality changes for the last five years in the area of Warszawa, it was found that there was danger of not complying with the requirements set by the European Union. The time limit by which the member countries have to adjust the PM10 concentration limits in their territories to the EU norms is June 2011.
Thermodynamics of the hydrolysis of adenosine triphosphate as a function of temperature, pH, pMg, and ionic strength

The hydrolysis of adenosine triphosphate plays such an important role in energy metabolism that the thermodynamic properties of the species involved have been determined, including the standard Gibbs energies and enthalpies of formation of its magnesium complex ions. When the pH and pMg are specified in addition to temperature, pressure, and ionic strength, the criterion for spontaneous change and equilibrium is provided by the transformed Gibbs energy G‘ that is defined by a Legendre transform. The use of a Legendre transform makes it possible to express all the thermodynamic properties of a reactant by use of a single function of temperature, pH, pMg and ionic strength. The expression for the standard transformed Gibbs energy of formation of a reactant like ATP (a sum of species) is a function of temperature, pressure, pH, pMg, and ionic strength. Nine Maxwell relations are used to calculate various thermodynamic properties and relations between them. It is of particular interest to see that the derivat.
Combined antitumoral therapy with nanoassemblies of bolaform polyisoprenoyl paclitaxel/gemcitabine prodrugs

We report here the design and synthesis of novel bolaform prodrugs in which the two headgroups are constituted of gemcitabine and/or paclitaxel anticancer drugs bound together through short polyisoprenoyl spacers. Thanks to the unique auto-assembling properties of the polyisoprenoyl linker, these bolaform prodrugs were found to self-assemble in aqueous media into 100–200 nm nanoassemblies. The synthesis of the prodrugs and the characterization of the nanoassemblies by DLS, TEM and cryoTEM are described. These gemcitabine/paclitaxel nanodevices with high drug payloads displayed improved in vitro activities on several human and murine cancer cell lines comparatively to nanoassemblies of the corresponding squalenoyl drugs alone or in combination.