Miracle-dz/UniFAR-FTUs huggingface dataset:
Rodlike Cellulose Microcrystals: Structure, Properties, and Applications

Summary: In this article we present some interesting properties of rodlike cellulose microcrystals (so-called “whiskers”). These microcrystals can be obtained from different cellulose sources such as wood, cotton, or animal origin. When submitted to acid hydrolysis, the cellulose fibers yield stable aqueous suspensions because of the presence of negative charges on the surface of the microcrystallites during the hydrolysis process. The obtained microcrystals are rod-shaped particles, the dimensions of which depend on the cellulose origin. For instance, the cotton whiskers have typical dimensions varying from 100 to 300 nm in length, L, and 8 to 10 nm in diameter, d, while those of the tunicate whiskers range from 100 nm to few micrometers in length and 10 to 20 nm in diameter. At very low concentrations, these whiskers are randomly suspended in water and form an isotropic phase. When the concentration reaches a critical value, the whiskers spontaneously display ordered phases showing interesting liquid crystal properties (nematic and chiral nematic). The chiral nematic orders can be retained after evaporation of the solvent (generally water), leaving iridescent films. The reflected color can be controlled by changing either the ionic strength or by applying an electric field. These colloidal particles have been investigated using several techniques including small-angle neutron scattering (SANS), small angle X-ray scattering, rheology, and more recently dynamic and static light scattering techniques (DLS and SLS) to highlight their static and dynamic behavior. Because of their geometry, important axis ratio (L/d), and high crystallinity, these rods have been also extensively used to process nanocomposites based on polymer matrices, to reinforce their mechanical properties. All these properties are discussed in this contribution. Rodlike nanocrystals in aqueous suspension (left, Tunicate, 1 wt.-%) and film (right), observed between cross-polarizers.
Evaluation of the Johnson and Ettinger Model for Prediction of Indoor Air Quality

Screening level models are now commonly used to estimate vapor intrusion for subsurface volatile organic compounds (VQCs). Significant uncertainty is associated with processes and models and, to date, there has been only limited field‐based evaluation of models for this pathway. To address these limitations, a comprehensive evaluation of the Johnson and Ettinger (J&E) model is provided through sensitivity analysis, comparisons of model‐predicted to measured vapor intrusion for 11 petroleum hydrocarbon and chlorinated solvent sites, and review of radon and flux chamber studies. Significant intrusion was measured at five of 12 sites with measured vapor attenuation ratios (αm's) (indoor air/source vapor) ranging from ∼1 × 10−6 to 1 × 10−4. Higher attenuation ratios were measured for studies using radon, inert tracers, and flux chambers; however, these ratios are conservative owing to boundary conditions and tracer properties that are different than those at most VOC‐contaminated sites. Reasonable predictions were obtained using the J&E model with comparisons indicating that model‐predicted vapor attenuation ratios (αp's) were on the same order, or less than the αm's. For several sites, the αm were approximately two orders of magnitude less than the αp's indicating that the J&E model is conservative in these cases. The model comparisons highlight the importance in using appropriate input parameters for the J&E model. The regulatory implications associated with use of the J&E model to derive screening criteria are also discussed.
Design and development of papain–urea loaded PVA nanofibers for wound debridement

Devitalized tissues present in a wound bed serve as a reservoir for bacterial growth and contain elevated levels of inflammatory mediators that promote chronic inflammation and impair cellular migration necessary for wound repair. Effective wound cleansing and debridement are essential for granulation and re-epithelization. Among various debridement methods, enzymatic debridement is a highly selective method that uses naturally occurring proteolytic enzymes. Papain combined with urea has been widely used to remove necrotic/devitalized tissues. Our approach is to encapsulate papain and urea in PVA nanofibers to bring out sustained release to enable breakdown of fibrinous material in necrotic tissue and enhance wound healing. Physico-chemical characterization of nanofibers depicted the enzyme interaction with the polymer and also confirmed that the enzyme was evenly distributed in the nanofibers in an amorphous state. Fluorescence spectroscopy confirmed that the structural integrity of the enzyme was maintained after encapsulation. The results of antibacterial activity along with cell compatibility assays confirm the structural and functional integrity of the enzyme preparation along with the biocompatibility of the electrospun nanofiber and thereby provide more suitability as a dressing for wound debridement.
OPTICAL TRAPPING AND FLUORESCENCE DETECTION IN LAMINAR-FLOW STREAMS

An optical laser trap with fluorescence excitation/emission capability has been integrated in a flow cytometric geometry for the study of microparticle confinement and off‐axis fluorescence detection in laminar flow streams. Measurements of particle escape velocity, trapping efficiency, and fluorescence intensity are presented for 2 μm diameter dye‐tagged latex microspheres in laminar flow streams having velocities of up to 12 mm/s. Experimental results are compared with theoretical values for flow velocity and fluorescence intensity and found to be in excellent agreement.
A dual-band feed system

With the dual-reflector antenna configuration widely used for both earthbound and spacecraft antennas, the feed design is a crucial part of the overall system. While feed horns have been developed to cover continuous bandwidth ratios of at least 2:1, widely separated bands are more difficult to design effectively within a single feed. To achieve the necessary bandwidth for, say, C/Ku-band simultaneous operation, the dielectrically loaded corrugated, dual-frequency horn as described by M.S. Narasimhan and M.S. Sheshadri (see IEEE Trans. Antennas. Propag., vol.Ap-27, 858-60, 1979), is a strong candidate. The authors outline their approach in analysing this type of feed horn used in conjunction with a coaxial diplexer to excite the two bands in the horn.
Influence of urea on sodium decyl sulfate micellization by kinetic and solubility studies

Stopped-flow and solubility studies were used to ascertain the effect 0-7 M urea had upon the micellization of anionic surfactants with sodium decyl sulfate (SDeS) as the surfactant of choice. The complexation of Ni 2+ ion with the ligand trans-pyridine-2-azo-p-dimethylaniline (PADA) was the probe reaction for the stopped-flow investigation. The addition of urea increased the critical micelle concentration, and attenuated the rate enhancement ordinarily seen with this complexation in SDeS micellar solution. Urea interacted positively with water in the sense that the complexation rate doubled at 7 M urea with no surfactant present. In micellar solution, urea rendered the SDeS micelles far less accommodating to both Ni 2+ ion and PADA which indicated that both the surface and core micellar regions were considerably urea modified especially beyond 4 M urea.
Charging of particulates in the corona field of roll-type electroseparators

The physics of corona charging phenomena is of paramount importance for the development of such electrotechnologies as precipitation of dust, spraying of powders and selective sorting of particulate mixtures. This study focused on the use of corona discharge in electroseparation processes. Crude theoretical evaluations pointed out that the required corona current density and high-voltage level in this application depend on various factors, such as material characteristics, feed rate and configuration of the electrode system. Experiments carried out on a laboratory roll-type electroseparator demonstrated the capability of a new corona electrode design to generate an extended and quasi-uniform corona field. Stable corona discharges were obtained when energizing that electrode at both positive and negative polarities from a reversible non-filtered full-bridge high-voltage rectifier. The voltage-current characteristics of the corona discharge from the new electrode were determined under various operating conditions: (i) without material in the inter-electrode gap; (ii) with a monolayer of a 50% aluminium-50% polyvinyl chloride particulate mixture on the surface of the grounded electrode; (iii) with a similar monolayer of metallic particles (99% aluminium); and (iv) with a layer of insulating particles (99% polyvinyl chloride). In each case, attention was paid to the upper acceptable limit of operating voltage, as well as to some side effects of corona discharges, such as audible noise and ozone generation. The efficacy of corona charging was assessed by electroseparation tests involving two groups of particulate materials: (i) barley grains, impurified with weeds and soil particulates; and (ii) granular mixtures of metals and plastics, yielded by chopping electric wire and cable scrap. Several practical considerations were formulated, based on a critical evaluation of the experimental results.
An investigation of inter-stakeholder dynamics supportive of stem, community-based learning

Community-based learning (CBL) allows universities to leverage educational interactions with various non-university stakeholders.In a STEM context, CBL often includes service-learning, outreach, mentorship programs, pre-college research fairs, and internshipswhere experiential education commonly provides the pedagogical foundation. Such initiatives are predominantly university-centeredand the emphasis is on student or programmatic outcomes. This approach limits the potential synergistic benefits of CBL and canminimize the role of, and outcomes for, non-university stakeholders. The study presented here seeks to further knowledge of howinter-stakeholder dynamics can support STEM CBL outcomes through a qualitative exploration of the interdependencies betweenstakeholders. Thirty stakeholders from various groups across CBL initiatives organized around a large, public university in SouthAmerica were interviewed. Interview data was analyzed using a constant comparative method to reveal emergent findings. Findingsinclude characteristics and mechanisms of the relationships that support positive outcomes amongst STEM CBL stakeholders. Thefindings are structured in three categories: (i) shared purpose; (ii) holistic awareness; and (iii) linked commitment. The empiricalfindings describing the interdependencies between CBL stakeholders can broaden the current STEM CBL discourse and informapproaches that generate beneficial outcomes for all stakeholders. The extent to which STEM CBL and the supporting relationships are understood in contexts outside the U.S. is limited, a gap in the literature that is addressed through the SouthAmerican context of this study. Results indicate that an understanding of the inter-stakeholder dynamics can be leveraged toenhance STEM CBL programs by supporting outcomes for all stakeholders.
Research progress of hydrate-based CO2 separation and capture from gas mixtures

Hydrate-based CO2 separation and capture from gas mixtures containing CO2 has gained growing attention as a new technology for gas separation, and it is of significance for reducing anthropogenic CO2 emissions. Previous studies of the technology include the thermodynamics and kinetics of hydrate formation/dissociation, hydrate formation additives, analytical methods, separation and capture progress, equipment and applications. Presently, the technology is still in the experimental research stages, and there are few reports of industrial application. This review examines research progress in the hydrate formation process and analytical methods with a special focus on laboratory studies, including the knowledge developed in analog computation, laboratory experiments, and industrial simulation. By comparing the various studies, we propose original comments and suggestions on further developing hydrate-based CO2 separation and capture technology.
Desertification and climate change: Saudi Arabian case

This paper concentrates on the possible relationships between the climate change and desertification in arid regions. It is stated that the global warming will cause vertical expansion of air volumes over the three free water surfaces (Red Sea, Arabian Sea and Arabian Gulf) around the Arabian Peninsula (AP) causing air movement enhancement towards inlands and hydrological cycle intensification. Finally, for comparison purposes the rainfall predictions up to 2100 on the basis of NCAR-A2 scenario is given as the product of quadrangle downscaling (QD) methodology. It is shown that climate change may accelerate desertification at coastal areas of the AP.
Nucleation and Growth of Crystals at High Supersaturation

Homogeneous nucleation followed by diffusion controlled crystal growth was observed in highly supersaturated solutions of BaSO4, BaCrO4, BaMoO4, BaWO4, BaCO3, PbSO4, PbCrO4, PbCO3, SrSO4, and CaWO4. In the range of concentrations where the number of homogeneously nucleated particles is larger than the number of heteronuclei the induction period decreases from 1 to 10−4 sec, and the number of particles found per cm3 increases from 107 to 1012 with increasing concentration. Theoretical maps showing the rate determining mechanisms of crystal growth are drawn for different values of the physical parameters, primarily crystal size, supersaturation ratio, and interfacial tension. The techniques used for rapid mixing and for film recording are described.
Fate of Pesticides in the Environment and its Bioremediation

The present paper is an overview of the presence and fate of pesticides as persistent organic pollutants in the environment as well as of the potential for their detoxification, also combined with chemical and physical treatment. It contains information gathered from a range of currently available sources. The fate of pesticides in the environment is analyzed considering the processes that determine their persistence and mobility, grouped into transport, transfer and transformation processes. Few pesticide characteristics such as persistence, mobility and biodegradability are emphasized. The fate of a pesticide and the potential for its persistence and mobility from the site of application are considered to be affected by the chemical and physical properties of the pesticide, site characteristics such as soil and groundwater individuality, climate and local weather conditions, biological population, and the handling practices of the pesticide user. Bioremediation, as one of the most environmentally‐sound and cost‐effective methods for the decontamination and detoxification of a pesticide‐contaminated environment is discussed especially considering the factors affecting the biodegradability of pesticides such as biological factors and the characteristics of the chemical compounds. In situ and ex situ bioremediation as possible types of bioremediation activities are weighted up. Also, the paper includes some considerations for developing strategies regarding the choice of bioremediation technology, as well as advantages and disadvantages of the bioremediation of environmental components polluted with pesticides.
FREE ENERGY CALCULATIONS : APPLICATIONS TO CHEMICAL AND BIOCHEMICAL PHENOMENA

The author will review the applications of free energy calculations employing molecular dynamics or Monte Carlo methods to a variety of chemical and biochemical phenomena. The focus is on the applications of such calculations to molecular solvation, molecular association, macromolecular stability, and enzyme catalysis. The molecules discussed range from monovalent ions and small molecules to proteins and nucleic acids.
A comparative study of the analytical methods for the determination of polycyclic aromatic hydrocarbons in seafood by high‐performance liquid chromatography with fluorescence detection

Summary This study was performed to establish a rapid analytical method to determine the presence of fourteen polycyclic aromatic hydrocarbons (PAHs) in seafoods by high-performance liquid chromatography with fluorescence detection (HPLC/FLD). The samples were prepared using two methods: the Quick, Easy, Cheap, Effective, Rugged, Safe (QuEChERS) method and the alkali digestion method. The QuEChERS method involved a convenient and effective solid–liquid extraction and a simple purification. The alkali digestion method was comprised of a liquid–liquid extraction after saponification with potassium hydroxide followed by purification. The limits of detection (LODs) and limits of quantification (LOQs) of the QuEChERS method ranged from 0.05 to 1.60 μg kg−1, and those of the alkali digestion method ranged from 0.28 to 5.18 μg kg−1. The repeatability for all target analytes was similar for the two methods, that is, 0.66–4.24% and 0.26–5.75% for the QuEChERS and alkali digestion methods, respectively. At analyte concentrations of 2.5–50 μg kg−1, the recovery of the QuEChERS method ranged from 86.87% to 115.67% and that of the alkali digestion method ranged from 69.22% to 100.21%.
Input, flux, and persistence of six select pesticides in San Francisco Bay

Temporal patterns of pesticide inputs to San Francisco Bay were identified and correlated with timing of application and transport mechanism. Fluxes were calculated from measured concentrations and estimated flow. Persistence of the pesticides under typical riverine or estuarine conditions were estimated from laboratory experiments. Simazine was detected most frequently and had the highest flux into the Bay, which could be explained by its continuous use and long half-life. In comparison, diazinon was detected at lower concentrations and had a lower flux which corresponded to its lower use and shorter half-life. The order-of-magnitude lower fluxes of carbofuran and methidathion corresponded to their lower use and expected hydrolysis. Molinate was detected at the highest concentration but its flux was lower than expected, considering its very high use and persistence in the laboratory experiments. Additional loss of molinate is likely to occur from volatilization and photodegradation on the rice fields. Although thiobencarb had the second highest use, it had the lowest flux of the six pesticides, which can be attributed to its loss via hydrolysis, photodegradation, volatilization, and sorption to sediments. Fluxes into San Francisco Bay were equal to or greater than those reported for other estuaries, except for the Gulf of Mexico.
Simultaneous Quantification of Three Bioactive Lignans, viz., Phyllanthin, Hypophyllanthin, and Niranthin from Phyllanthus amarus Using High-Performance Thin-Layer Chromatography

Phyllanthus amarus, a well-known drug of the Indian Systems of Medicine, possesses a wide variety of pharmacological activities including anticancer, anti-inflammatory, hepatoprotective, immunomodulatory, nephroprotective, and radioprotective activity. The pharmacological activity of P. amarus is due to the presence of various lignans and flavonols, the major ones being phyllanthin, hypophyllanthin, and niranthin. A simple high-performance thin-layer chromatographic method has been developed for the simultaneous quantification of these three lignans from the whole plant of P. amarus. The optimized mobile phase n-hexane-ethyl acetate-glacial acetic acid (9:3:0.3, v/v) gave good separation of phyllanthin, hypophyllanthin, and niranthin on thin-layer chro-matography (TLC) silica gel 60 F254 layers when quantified at 230 nm. The developed method was validated according to the International Conference on Harmonization (ICH) guidelines for precision, repeatability, accuracy, and linearity. Peak identity and purity were determined. This is the first report of simultaneous quantification of phyllanthin, hypophyllanthin, and niranthin from P. amarus using normal phase TLC silica gel 60 F254 plates. The developed method is simple, precise, accurate, cost-effective, and less time-consuming.
Methyl halides from Antarctic macroalgae

Various species of Antarctic macroalgae have been found to produce and release methyl halides at mean values of 34.7 pmol g−1 waw (wet algal weight) d−1 (methyl chloride), 1.98 pmol g−1 waw d−1 (methyl bromide) and 1.68 pmol g−1 waw d−1 (methyl iodide) into the seawater. Compared to temperate macroalgae, Antarctic macroalgae showed an approximately 10 to 50‐fold lower release of these compounds. Due to the lower release and the restriction to the Antarctic region, Antarctic macroalgae may play a minor role in the global production of methyl halide, but have to be considered as biogenic contributors for methyl halides to the halocarbon budget in the Antarctic environment. Additional, investigated bromoform release, brominating activity and dimethylsulfoniopropionate (DMSP) concentrations detected in Antarctic macroalgae showed no correlation with methyl halides release rates. Therefore, a formation different to suggested enzymic pathways or origin from DMSP reacting with halides can be assumed.
Responses of soil microbial respiration to thermal stress in alpine steppe on the Tibetan plateau

Extensive research has focused on the temperature sensitivity of microbial respiration in tundra and alpine meadows. However, the response of microbial respiration to thermal stress in alpine steppe soils, which have less organic matter and greater aeration, has received less attention. We investigated spatial and temporal variations in microbial respiration using an incubation experiment under different temperature (0, 15 and 30°C) and different percentages of water‐holding capacity (WHC) (50 and 100%) conditions in the alpine steppe, and using a subsequent cooling experiment determined the ‘thermal stress' of soil microorganisms in response to increased temperature in the alpine steppe ecosystem. Microbial respiration rates decreased with increasing temperature at both 50 and 100% WHC for three sampling locations. Thermal stress of soil microorganisms under increased temperatures was found in the alpine steppe because subsequent cooling led to an increase in microbial respiration rates. Soil moisture did not affect microbial respiration, but the temperature sensitivity (Q10) of microbial respiration varied with the interactive effect between soil moisture and sampling location. Our findings suggest that the response of microbial respiration to high temperature may not be always positive as bacteria may experience thermal stress in the alpine steppe. Therefore, it is necessary to include thermal stress responses in alpine steppe models, as they may represent an important negative feedback effect on microbial respiration.
Structures and phase diagrams of N2 and CO to 13 GPa by x‐ray diffraction

The structures and phase transitions of N2 and CO were studied by powder x‐ray diffraction from 100 to 300 K and 4 to 13 GPa. Three solid phases, β, δ, and e, were observed in each material. The known β and δ solids were confirmed to have hexagonal space group P63/mmc and cubic space group Pm3n, respectively. From refinements using photographic x‐ray intensities, the new e‐N2 and e‐CO structures were determined to be rhombohedral R3c. There are eight ordered molecules in the e‐N2 unit cell with a=5.928 A and α=85.14° at 110 K and 7.8 GPa, and eight ordered molecules in the e‐CO unit cell with a=6.059 A and α=85.73° at 100 K and 5.5 GPa. The CO molecules are randomly oriented head to tail. The δ–e transition takes place through an ordering and small displacement of the N2 and CO molecules, accompanied by a slight extension of the lattice along a cube diagonal. Molar volumes are presented over an expanded P‐T region. Recent theoretical calculations using lattice energies, molecular dynamics, and symmetry c.