Miracle-dz/UniFAR-FTUs huggingface dataset:
Sorption and Desorption of Acetonitrile on Montmorillonite from Aqueous Solutions

The sorption and desorption of acetonitrile on K, Na, Ca, and Mg montmorillonite from aqueous solutions were determined using a I4C isotope tracer method. The heat of sorption of acetonitrile on K, Na, and Ca montmorillonite at two concentrations was determined using a Calvet microcalorimeter. The infrared spectra of the clay-waterorganic systems were recorded on a Fourier-transform infrared spectrometer and the c-axis spacings of K, Ca, and Mg montmorilloni te in the acetonitrile solutions were determined by x-ray diffraction. It was found that the sorption and desorption of acetonitrile on the four homoionic montmorillonites are reversible, and that the sorption of acetonitrile is exothermic on K and Ca montmorillonite, but endothermic on Na montmorillonite. Further, it was found that the wavenumbers of the C=N band and the C-H band for the acetonitrile molecules on the clay surfaces do not differ from those in the solution. It was also observed that the sorption of acetonitrile affected the c-axis spacing of the various homoionic montmorillonites differently. These results led to the conclusion that the sorption of acetonitrile on montmorilloni te is not due to any specific bonding between the organic molecules and the clay surfaces, but rather to a distribution or partition between the interfacial phase and the bulk-solution phase. Analysis was provided to show that a partition mechanism does not necessarily yield a linear isotherm, especially when the concentration of the organics is high.
Shelf-life of food powders

Abstract: Food powders should appear homogeneous and keep free floating properties during storage and chemical changes should be minimized. The shelf-life of food powders as influenced by both physical changes and chemical reactions is controlled by the availability of water. Crystallization together with non-enzymatic browning and oxidative deterioration are prevented in food powders in glassy states, and water activity and temperature together determine critical storage conditions. The construction and use of temperature/water activity phase diagrams to define storage conditions for food powders are strongly encouraged.
The geographical distribution of meteorological parameters associated with high and low summer ozone levels in the lower troposphere and the boundary layer over the eastern Mediterranean (Cairo case)

In continuation of previous research for evaluation of the high ozone levels observed during summer time over the eastern Mediterranean, MOZAIC profiles collected at the airport of Cairo from 1994 to 2008 are analysed. Average profiles corresponding, respectively, to the highest and the lowest ozone mixing ratios for the 0–1.5 km layer over Cairo in summer (JJA) (94 profiles) are examined along with their corresponding composite maps of geopotential height (and anomalies), vertical velocity (and anomalies), specific humidity anomalies, precipitable water anomalies, air temperature anomalies and wind speed at 850 hPa. In addition, backward trajectories arriving in the boundary layer over Cairo during the days with highest or lowest ozone mixing ratios are examined. During the 7% highest ozone days at the 0–1500 m layer over Cairo, very high ozone concentrations of about 80 ppb on average are observed from the surface up to 4–5 km altitude. The difference in ozone concentrations between the 7% highest and the 7% lowest ozone days reaches maximum values around 60 ppb close to the ground. During the highest ozone days for both 1.5–5 and 0–1.5 km layer, there are extended regions of strong subsidence in the eastern Mediterranean but also in eastern and northern Europe and over these regions the atmosphere is dryer than average. In addition, characteristic profiles with the highest ozone concentrations in the 0–1500 m layer are examined in order to assess the influence of atmospheric transport and photochemistry on the ozone concentrations over the area.
THERMAL INACTIVATION KINETICS OF BROMELAIN IN PINEAPPLE JUICE

Bromelain, a protease present in pineapple, needs to be inactivated to assure consumer acceptance and product stability in canned pineapple products. Available literature reports thermal inactivation kinetics of bromelain extracted from plant stem, not from fruit pulp and juice. Determination of thermal inactivation kinetics of bromelain in pineapple juice would lead to optimum heat treatment conditions for minimum loss of juice quality when thermal degradation kinetics of quality factors are also known. Thermal inactivation kinetics of bromelain in pineapple juice were characterized by isothermal experiments at 55, 60, 63, 65, and 67°C. Thermal inactivation followed first-order kinetics, and isothermal rate constants varied with temperature in accordance with the Arrhenius equation. The calculated activation energy was 3.26 10 5 J/mol, and the frequency factor (reference rate constant) was 1.37 10 50 min –1 . A model for bromelain thermal inactivation was developed to predict the residual enzyme activity in response to any dynamic temperature-time heat treatment, and successfully tested with dynamic heating experiments.
Detailed x‐ray photoelectron spectroscopy valence band and core level studies of select metals oxidations

The present study reports the use of monochromatic, high resolution x‐ray photoelectron spectroscopy to investigate the evolution of the s and p bands of select metals, and the resulting O(2p) bands of their oxides as the process of oxidation (or reduction) sequentially occurs. Those metals in the groups I B, II B, III A, and IV A, with their relatively deep d bands, are of principal concern. Such questions as the uniformity (or lack thereof) of the movement of electron density between bands, and subband regions, have been explored. Correlations are also drawn between the changes experienced by the core and valence states. The progressive difference found for oxide formation throughout this region of the Periodic Table is considered. The unique property of Sidgwick inert s pairs is also investigated.
Gold nanoparticle formation using Shewanella oneidensis: a fast biosorption and slow reduction process

BACKGROUND: The metal respiring bacterium Shewanella oneidensis has previously been used for reduction of Pd(II) into Pd(0) nanoparticles. This study investigated whether Shewanella oneidensis could also perform the reduction of Au(III) to Au(0). The kinetics of both the biosorption and reduction of Au(III) were studied. RESULTS: Biosorption of Au(III) was a fast and efficient process, and depended on the presence of an electron donor, the pH and the medium used. The reduction process, however, appeared to be a slow process, requiring the presence of an electron donor. As reduction also occurred in heat-killed cells, it is suggested that the reduction is non-enzymatic. At a concentration of 100 mg L−1 Au(III), the nanoparticles were mainly smaller than 10 nm and precipitated intracellularly. With H2 as the electron donor, it was shown that the location of the particles and the size could be steered by changing the concentration of Au(III). CONCLUSIONS: After a fast biosorption and slow reduction process, Au(0)-nanoparticles were formed inside the cells or on the cell wall of Shewanella oneidensis. In most cases, these particles had interesting properties, such as small size and a narrow size distribution, which can make them suitable for applications in, for example, catalysis. Copyright © 2010 Society of Chemical Industry
The effective phase of soft RF pulses

In this article, the seemingly trivial relation between the spin nutation phase and the phase of radiofrequency (RF) pulses used in NMR is discussed, which in the case of soft (selective) pulses appears more subtle. Unlike hard pulses applied at a common carrier frequency, soft pulses usually have different frequency offsets in the same sequence and their nutation phase cannot be directly linked with the RF phase shift, as the phase shift has no absolute meaning for waves of different frequency. The problem is further complicated in MRI, where RF pulses are accompanied by a time-dependent slice selection field gradient leading to surprising effects, for example, when two consecutive pulses of identical frequency and phase rotate the spins around different axes depending on slice position. A rule is described that lets the effective nutation phase be derived from the time course the RF phase. Ways to control this time course using various options of digital synthesis are presented. The discussion is illustrated by two popular MRI sequences—fast spin echo (RARE) and balanced steady-state free precession (true FISP)—whose phase sensitivity easily leads to a pitfall when the frequency synthesis is not programmed with sufficient care. © 2015 Wiley Periodicals, Inc. Concepts Magn Reson Part A 43A: 127–137, 2015.
Rectifying junctions in peripherally-substituted metallophthalocyanine bilayer films

Thin bilayer films formed by the sequential vapor deposition of two different peripherally-substituted metallophthalocyanines exhibit rectifying behavior toward an applied dc voltage. The degree of rectification is shown to be enhanced in the presence of oxygen. These bilayer films demonstrate that device activity can be imparted to a phthalocyanine junction via «band tuning» and represent the first examples of non-Schottky type rectification observed in phthalocyanine-based junctions. Analysis of the forward current-voltage characteristics suggests that a possible Frenkel-Poole carrier detrapping mechanism exists in these systems. Preliminary band structure calculations indicate that the bilayers are actually p-p isotype heterojunctions
Glucolipotoxicité dans les cellules bêta pancréatiques

Le diabete de type 2 est une pathologie chronique complexe associant une alteration de secretion de l'insuline par le pancreas et une resistance a l'insuline au niveau des tissus peripheriques, notamment au niveau du foie et du muscle squelettique. Son origine est multifactorielle, alliant des anomalies genetiques et environnementales, en particulier nutritionnelles. Un des mecanismes par lesquels les facteurs nutritionnels (comme les glucides et les lipides en exces) contribuent au developpement du diabete et a son aggravation est la glucolipotoxicite. En effet, l'elevation de la glycemie et des lipides plasmatiques, ainsi que l'accumulation ectopique de lipides dans les tissus, participent au developpement de l'insulinoresistance hepatique et musculaire et aux dysfonctions des cellules beta, en partie via l'induction d'un stress metabolique, impliquant notamment le stress oxydant, le stress du reticulum endoplasmique (RE) et la perturbation de l'homeostasie calcique. Nous avons etudie les effets de la glucotoxicite et de la lipotoxicite dans les cellules beta pancreatiques et les mecanismes impliques. Nous nous sommes aussi interesses a des traitements potentiellement protecteurs de la fonction beta-pancreatique. Nous avons fait l'hypothese que les effets benefiques de l'inhibition du systeme renine-angiotensine sur l'incidence du diabete de type 2 chez l'homme etaient medies par une action directe sur les cellules beta. Nos resultats montrent que le glucose chronique a une dose elevee entraine une reduction de la secretion d'insuline des cellules beta des ilots de Langerhans humains par une action conjointe sur le stress du RE, le stress oxydant et l'homeostasie calcique. L'inhibition du SRA a permis de restaurer cette fonction grâce notamment a une action inhibitrice sur la voie Phospholipase C-IP3-Calcium
Azobenzenes and catalysis

Azobenzene is the most extensively used class of chromophore in a large variety of applications. Recently, the use of azobenzene derivatives was developed in catalysis especially as a promoter. This paper aims to provide a global overview of the main access to the diazo compounds from 2010 as well as their use as a reactant or a promoter in organometallic catalysis.
COD Removal of Washing Water by Photodegradation

Degradation of the wastewater of washing oil tanks after degreasing and minimal treatment by photocatalysis is studied by using a rotating photoreactor and TiO2 photocatalyst of Degussa P25. Effects of irradiation time and pH value on removing efficiency are investigated. The results show that the COD down to about 80mg/L can be achieved at the irradiation time of about 4-5 hours at mild pH valus. At the pH value from 1.5 to 3.2, the COD down to about 80mg/L can be achieved at the irradiation time less than 1 hour, and the COD down to about 20mg/L could be achieved at the irradiation time of about 4 hours at a pH value of about 3.2.
Phenols as Antioxidants

1 Introduction 2 Kinetics and Mechanism 3 Efficiencies of Phenolic Antioxidants 4 Chemical Calculations on Phenols 5 Future Prospects for Antioxidants Keywords: phenols as antioxidants; phenolic antioxidant efficiencies; inhibited oxygen uptake (IOU) measurement techniques; phenol hydrogen atom donating ability; electron delocalization in phenoxyl radicals; solvent interactions with attacking radicals; kinetic solvent effects (KSE) and hydrogen atom abstraction from phenols; phenol chemical calculations
Synthesis of ZnO/MgO Nanocomposites by Electrochemical Method for Photocatalytic Degradation Kinetics of Eosin Yellow Dye

ZnO/MgO has been synthesized by electrochemical method and characterized by UV-Visible spectroscopy, IR spectroscopy, SEM, XRD, PALS and density measurement data. The UV-Visible spectroscopy results reveals that the band gap energy of ZnO/MgO nanocomposite to be 3.9 eV. The XRD results show that the crystallite size to be 17.55 nm calculated using Williamson-Hall plot. The PALS measurements reveal that the ZnO/MgO nanocoposites consists of more defects and vacancies than ZnO. An improvement in photocatalytic degradation of Eosin Yellow (EY) dye in comparison to commercially available pure ZnO was observed. The photodegradation efficiency for ZnO/MgO and ZnO were found to be 84.82% and 27.97% respectively. The enhancement in photocatalytic activity of ZnO/MgO nanocomposite was because of the highly hygroscopic and nanoporous MgO. The MgO layer contains more H2O and hydroxyl groups and offers a larger surface area.
La norme environnementale ISO 14001 est-elle applicable à l'exploitation agricole ?

Cet article etudie les conditions d'application de la norme ISO 14001 relative au systeme de management environnemental des exploitations agricoles et propose quelques suggestions susceptibles de favoriser leur mise en place dans le monde agricole. Ces propositions s'inspirent a la fois d'une etude des texte de la norme et d'un essai de transposition d'experiences industrielles et agricoles. Quelques remarques critiques sur les limites du travail effectue le concluent, offrant ainsi au chercheur de nouvelles pistes de reflexion. / This paper studies the conditions of application of the standard ISO 14 001 (Environnemental Management Systems) in farms. It proposes some suggestions to make the application of Environnemental Management System in the agricultural world easier. These suggestions come from a study of texts of ISO 14001 and an attempt of transposition of some industrial and agricultural experiences. This study ends by appraisal of this work and gives some new tracks.
Study of the characteristics current-voltage and capacitance-voltage in nitride GaAs Schottky diode

This article reports the study of Au/GaN/GaAs Schottky diodes, where the thin GaN film is prepared by nitridation of GaAs substrates with thicknesses of 0.7 and 0.8 nm. The resulting GaN sample with thickness 0.8 nm is then treated with an annealing operation (heating to 620 °C) to improve the current transport. The current-voltage ( I-V ) and capacitance-voltage ( C-V ) of the Au/GaN/GaAs structures were investigated at room temperature. In fact, the I-V characteristics show that the annealed sample has low series resistance ( R s ) and ideality factor ( n ) (63 Ω, 2.27 respectively) when compared to the values obtained in the untreated sample (1.83 kΩ, 3.31 respectively). The formation of the GaN layer on the gallium arsenide surface is investigated through calculation of the interface state density N SS with and without the presence of series resistance R s . The value of the interface state density N SS ( E ) close to the mid-gap was estimated to be in the order of 4.7×10 12 cm -2 eV -1 and 1.02× 10 13 cm -2 eV -1 with and without the annealing operation, respectively. However, nitridation with the annealing operation at 620 °C improves the electrical properties of the resultant Schottky diode.
Challenges in participatory primary stress management interventions in knowledge intensive SMEs

While knowledge intensive SMEs have recognized the need for change with respect to productivity and wellbeing, and to some extend have access to tools and methods for enabling this, they still lack process competences and are uncertain about how to approach primary stress interventions and initiate relevant change processes. This paper presents the outline of our research and development project on participatory primary stress management interventions in knowledge intensive SMEs, as well as the preliminary results and related implications. The research and development project is conducted in order to develop an operational model which SMEs can use when they want to initiate participatory primary stress management interventions in their company. The development project builds on a process model for participatory primary interventions in larger knowledge intensive companies and the premises behind this model in combination with other theories which have been used successfully in other interventions. The project is only in its initial phases in conducting the intervention, but so far the preliminary results indicate that management support and allocation of resources is vital, that internal facilitators are important drivers of the change process and that easy-to-use tools are requested from the involved company actors. Given that the interventions in the selected companies are conducted successfully we argue that a new organizational capability to address work-related stress in a collective and collaborative manner is developed in the participating companies. With a successfully conducted intervention we mean that the companies have been able to implement their own change proposals in a collective and collaborative process. By developing this organizational capability we expect that the companies would be able to repeat the process with new change proposals. The research builds on observations, participatory action research, interviews and surveys.
The Role of BMI and Blood Pressure in the Relationship Between Total Cholesterol and Disability in Chinese Centenarians: A Cross-Sectional Study

Background: Lower serum lipid metabolism might be associated with the decline of activity of daily living in the extreme longevity group. However, studies on models and possible paths of this correlation between total cholesterol (TC) and disability in centenarians are scarce. The aim of this study was to verify this correlation and explore the mediating effect of BMI and blood pressure on this relationship in Hainan centenarians. Methods: We conducted a cross-sectional analysis of 1002 centenarians from the China Hainan Centenarians Cohort Study (CHCCS). Data on demographics, anthropometry data, lifestyle, and TC levels were collected through interviews, physical examinations, and laboratory tests. The Barthel index and Lawton index, measuring the disability status, were used to estimate the activity of daily living (ADL) and instrumental activity of daily living (IADL). A multivariable logistic regression model was used to explore the correlation between disability and TC levels. Mediation analyses were used to explore the both direct and indirect effects of TC level on disability. Results: After adjusting for covariates, with 1 mmol/L increment in TC, the adjusted odds ratios (ORs) of ADL severe disability and ADL moderate & severe disability were 0.789(95%CI: 0.650–0.959) and 0.822(95%CI: 0. 0.699–0.966), respectively. There was a significant declining trend in the prevalence of different types of disability with increment in TC. The correlation was more pronounced among Hainan female centenarians. In the analysis of mediating effect among the female population, BMI significantly mediated the effect of TC levels on different types of disability. BMI and SBP, as chain mediators, multiply and chain mediated the effect of TC levels on IADL. Conclusion: Low TC levels might be correlated with a higher frequency of disability in female centenarians, and this correlation might be mediated by BMI and blood pressure.
Polymeric Nanocomposites—Polyhedral Oligomeric Silsesquioxanes (POSS) as Hybrid Nanofiller

Abstract Polyhedral oligomeric silsesquioxane (POSS), a hybrid nanostructured macromer has been used in the last decade for preparation of polymeric nanocomposites. Its versatile chemistry, which lends it for almost infinite chemical modification, sets it apart from other nanostructured fillers like nanoclays, carbon nanotubes, and carbon nanofibers. Depending on its functionality, 3‐D network, bead or pendant type‐POSS based polymeric nanocomposites can be synthesized. These have the potential to be designed for products with specific nanostructures for specific end‐use applications. This article discusses the trends in current research involving use of POSS macromers for modification of mainly thermal and viscoelastic properties of various polymers.
Magnetic properties of a bishelical [4 + 4 + 4] trinuclear copper(II) complex

A peculiar [4 + 4 + 4] trinuclear Cu(II) bishelicate has been studied by X-ray diffraction techniques, FT–IR and UV–Vis spectroscopies, magnetic measurements and EPR spectroscopy. Magnetic susceptibility studies indicate a strong antiferromagnetic interaction (J/k = −194 K) between the three copper ions in the bishelicate. The existence of antiferromagnetic intermolecular interactions (z′J′/k = −0.91 K) was also determined. In spite of the presence of two magnetically different centres, only one signal is observed due to the exchange effects. Below 100 K the linewidth of the signals rapidly decreases and a typical exchange narrowed spectrum is observed at 4 K. The main contribution to the ground state wave function can be attributed to the dx2 − y2 orbitals, as expected for tetrahedrally distorted planar square Cu(II) chromophores.
A Tug-of-War Model Explains the Saltatory Sperm Cell Movement in Arabidopsis thaliana Pollen Tubes by Kinesins With Calponin Homology Domain

Upon pollination, two sperm cells are transported inside the growing pollen tube toward the apex. One sperm cell fertilizes the egg cell to form the zygote, while the other fuses with the two polar nuclei to form the triploid endosperm. In Arabidopsis thaliana, the transport of the two sperm cells is characterized by sequential forward and backward movements with intermediate pauses. Until now, it is under debate which components of the plant cytoskeleton govern this mechanism. The sperm cells are interconnected and linked to the vegetative nucleus via a cytoplasmic projection, thus forming the male germ unit. This led to the common hypothesis that the vegetative nucleus is actively transported via myosin motors along actin cables while pulling along the sperm cells as passive cargo. In this study, however, we show that upon occasional germ unit disassembly, the sperm cells are transported independently and still follow the same bidirectional movement pattern. Moreover, we found that the net movement of sperm cells results from a combination of both longer and faster runs toward the pollen tube apex. We propose that the observed saltatory movement can be explained by the function of kinesins with calponin homology domain (KCH). This subgroup of the kinesin-14 family actively links actin filaments and microtubules. Based on KCH's specific properties derived from in vitro experiments, we built a tug-of-war model that could reproduce the characteristic sperm cell movement in pollen tubes.