Miracle-dz/UniFAR-FTUs huggingface dataset:
Flow Injection Spectrofluorimetric Method for Determination of Chromium(VI) Using Stopped‐Flow Technique

Abstract A novel fluorescent reagent, pyridine‐2‐aldehyde benzothiazoline, was synthesized. The reaction between pyridine‐2‐aldehyde benzothiazoline and Cr(VI) was studied in detail. Based on the oxidation reaction, a highly sensitive and selective flow injection spectrofluorimetric method (using stopped‐flow technique) was developed for online determination of Cr(VI). Under the optimum experimental conditions, the oxidized product of pyridine‐2‐aldehyde benzothiazoline had excitation and emission maxima at 310 and 398 nm, respectively. The linear range was 7.6 × 10−3 ∼ 5.00 µg mL−1 of Cr(VI), the detection limit was 2.3 ng mL−1, and the maximum sampling rate was 40 h−1. The effect of interferences was studied. This proposed method was successfully applied to the determination of chromium in sludge. We thank the Important Project of National Natural Science Foundation of China (No.20335030) and Shandong Province Main Nature Science Foundation of China (No. Z2003B01) for the financial support of this work.
Combination of Olefin Metathesis and Enzymatic Ester Hydrolysis in Aqueous Media in a One‐Pot Synthesis

A new synthetic method for the preparation of cyclic malonic acid monoesters in aqueous media was developed based on the combination of a metathesis reaction and subsequent biocatalytic hydrolysis with a pig liver esterase in a one-pot synthesis. Both reaction steps proceed smoothly under optimized conditions in aqueous media requiring only a low amount of the metal catalyst for the metathesis reaction. Notably, the applied biocatalyst turned out to be highly compatible with the metal catalyst showing no significant influence on the enzyme activity.
Extending the Capabilities of Single Particle Mass Spectrometry: II. Measurements of Aerosol Particle Density without DMA

Particle density is an important and useful property that is difficult to measure because it usually requires two separate instruments to measure two particle attributes. As density measurements are often performed on size-classified particles, they are hampered by low particle numbers, and hence poor temporal resolution. We present here a new method for measuring particle densities using our single particle mass spectrometer, SPLAT. This method takes advantage of the fact that the detection efficiency in our single particle mass spectrometer drops off very rapidly as the particle size decreases below 100 nm creating a distinct sharp feature on the small particle side of the vacuum aerodynamic size distribution. Thus, the two quantities needed to determine particle density, the particle diameter and vacuum aerodynamic diameter, are known. We first test this method on particles of known compositions and densities to find that the densities it yields are accurate. We then apply the method to obtain the densities of particles that were characterized during instrument field deployments. We illustrate how the method can also be used to measure the density of chemically resolved particles. In addition, we present a new method to characterize the instrument detection efficiency as a function of particle size that relies on measuring the mobility and vacuum aerodynamic size distributions of polydisperse spherical particles of known density. We show that a new aerodynamic lens used in SPLAT II improves instrument performance, making it possible to detect 83 nm particles with 50% efficiency.
Incorporation of multiwalled carbon nanotubes into poly(vinyl alcohol) membranes for use in the pervaporation of water/ethanol mixtures

Multiwalled carbon nanotube (MWNT)/poly (vinyl alcohol) (PVA) blend membranes were prepared by the solution-casting method to determine the effect of MWNTs with nanoscale empty inner space along the tube length on the pervaporation performance of a PVA membrane in the separation of alcohol/water mixtures. The blend membranes were then characterized with several analytical methods such as transmission electron microscopy, differential scanning calorimetry, and X-ray diffractometry: Transmission electron microscopy showed that the MWNTs were homogeneously distributed through the PVA matrix. The glass-transition temperature of the PVA membrane was increased from 69.21 to 78.53°C via blending with MWNTs. The crystallinity of the PVA matrix decreased with increasing MWNTs up to 5 wt % from 41 to 36%. The pervaporation properties of the blend membranes were completely different from those of the pure PVA membrane in the separation of water/ethanol mixtures. The flux of the membrane was increased with the amount of MWNTs, whereas the separation factor was maintained up to 1.0 wt % MWNTs. However, beyond that, it was reduced. These results suggested that two factors, the crystallinity of the membrane and the diameters of the MWNTs, affected the performance of the membranes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Detection of Proteins by On‐Column, Non‐Covalent Labeling with NanoOrange During Capillary Zone Electrophoresis

Abstract To avoid prior derivatization of proteins with fluorescent reagents, on‐column labeling of non‐covalent dye NanoOrange on proteins was evaluated with sodium dodecyl sulfate (SDS) as an additive using laser induced fluorescence (LIF) monitoring in capillary electrophoresis (CE). Performance of NanoOrange in buffer solutions of various pH values was tested. Acidic buffer solution was found to be unsuitable for on‐column NanoOrange labeling. SDS enhanced the fluorescence intensities of basic proteins with high pI values. The fluorescence intensities of protein solutions with or without SDS additives were compared using a fluorescence spectrophotometer. The applicability of on‐column labeling and detection of staphylococcal enterotoxin B was also demonstrated. This on‐column labeling method provides a rapid, direct, widely applicable technique for protein studies.
Ultrasonic Convective Drying Kinetics of Clipfish During the Initial Drying Period

A hybrid drying system for high-intensity airborne ultrasound applied in convective drying was investigated for the drying of salted codfish (clipfish). Convective drying with ultrasonic assistance at 10, 20, and 30°C was compared to the same process without ultrasound. The Weibull model was used to model and investigate the drying behavior, and the effective diffusion in Fick's law was determined. The ultrasound decreased the drying time more at lower drying temperatures. The drying time was reduced by over 90% at a drying temperature of 10°C. For an industrial drying process at a temperature of 20°C, the drying time was reduced by 32.2%. The ultrasonic, convective drying of clipfish at a temperature of 20°C was faster than the same process without ultrasound at 30°C. The investigations showed a thermal effect for all products when ultrasound was applied. The specific moisture extraction ratio (SMER) in the investigated system was improved by 0.2 kgwater kWh−1. The heat transfer coefficient in the system used was increased by 32.6% for a heating process in a separate investigation, whereas for a cooling process no increased heat transfer coefficient was determined. The thermal effect might (at least partially) explain the faster drying of ultrasonic-assisted convective drying. The results obtained demonstrate the potential of airborne ultrasound in convective drying with regard to drying time, energy consumption, and product quality. Documentation of the thermal effect should be included in future R&D on this topic.
Molecular Dynamics of Staphylococcal Nuclease: Comparison of Simulation with 15N and 13C NMR Relaxation Data

Motional parameters for the atomic-level dynamics of staphylococcal nuclease are calculated from an 18-ns molecular dynamics simulation of the liganded enzyme and from a 3.75-ns simulation of the unliganded enzyme and compared with motional parameters calculated from 13C and 15N NMR relaxation data. Order parameters for backbone N−H and Cα−H bond vectors are on average in good agreement with experiment, indicating a similar degree of backbone flexibility. Somewhat greater flexibility is seen in the simulation of unliganded SNase, consistent with some experimental data. Alanine Cα−Cβ and Cα−H order parameters agree to within 5% for simulation while NMR finds the former to be 30% smaller than the latter; thus experimental reexamination of 13CH3 relaxation may be worthwhile. Average simulated and experimental rotation rates for the more rapidly rotating alanine and leucine methyl groups are in agreement. However, simulation predicts a much larger range of methyl rotation rates than is observed experimentally.
Theory of Liquid Crystals

A formalism based on cluster expansion for non-uniform fluid is found useful for the discussion of various thoeries of liquid crystals. Using the general formalism the equations which determine the order parameters for transtions in three-dimensional liquid crystals are derived. The proof by Lakatos that there is no phase transition within the approximation of the Onsager integral equation is found not to be correct in general. The isotopicnematic and nematic-smectic transitions in a two-dimensional system of rod-like molecules are estmated, the latter transition point agrees with what Alder and Wainwright estimate for a hard-sphere molecule in two-dimensions.
Seasonal variations in physicochemical characteristics and cyanobacterial diversity of a lake in Northern India

Physicochemical analyses and cyanobacterial diversity of Ramgarh Lake water were performed at five sampling sites during winter, summer, and monsoon seasons. Higher load of solids, carbon, and nutrients were persistent throughout the analysis that indicates the conversion of lake from oligotrophic to eutrophic nature. High nutrients load enhanced cyanobacterial biomass, while low nutrients load produced relatively less biomass. The physicochemical parameters of water samples revealed minimum 2.9 mg L−1 dissolved oxygen (DO) at site-1 during summer, while maximum (5.6 mg L−1) at site-4 in monsoon season. Maximum biochemical oxygen demand (BOD) (40 mg L−1) and chemical oxygen demand (COD) (126 mg L−1) were recorded at site-1 during summer, whereas minimum BOD (18 mg L−1) and COD (52 mg L−1) were evident at site-3 in monsoon season. Minimum concentration of nitrate (0.72 mg L−1) was recorded at site-3 in summer, whereas maximum 2.7 mg L−1 was present at site-5 in winter season. The phosphate concentration was maximum (0.52 mg L−1) at site-5 in summer, and minimum (0.18 mg L−1) was observed at site-4 in monsoon season. Cyanobacterial diversity was higher during all the seasons, and dominated by the species of Microcystis at all the five sampling sites.
Assessment of Odours from Livestock Wastes by a Photoionization Detector, an Electronic Nose, Olfactometry and Gas Chromatography-Mass Spectrometry

Abstract A photoionization detector (PID) and an electronic nose (EN) based on polypyrrole sensors, were evaluated against odour concentration measurement by olfactometry using odours from pig and chicken slurry. Both instruments were less sensitive than olfactometry, the PID and the EN giving responses down to 1,000 and 60,000 Odour Units m -3 in air, respectively. The EN was better at discriminating between different odours through the pattern of sensor responses. Gas chromatography-mass spectrometry (GC-MS) analysis was used to demonstrate differences in the chemical composition of the pig and chicken odour. Extraction of odorous compounds from slurries by solvent and purging with air gave different chemical profiles. Some of the major odour compounds were chemically unstable, so rapid, portable devices for odour measurement may have considerable advantages.
Effects of copper on the decomposition of plant residues, microbial biomass, and β-glucosidase activity in soils

Abstract Two types of soils (Brown Lowland soil and Ando soil), which were artificially enriched with different amounts of Cu, were incubated with or without pulverized orchard grass for 12 weeks at 25°C. For both soils with and without orchard grass amendment, the amount of CO2 evolved over the 12-week period of incubation decreased by the enrichment with Cu at a concentration exceeding 1,000 mg kg−1 soil. The decrease of the mineralization of added orchard grass in the Cu-enriched soil was conspicuous especially during the initial period of incubation. The amount of microbial biomass C at the end of the incubation was significantly reduced by the Cu enrichment regardless of the amendment with orchard grass. The relative decrease of the soil microbial biomass was much greater than that of the soil respiration. The amount of biomass C was negatively correlated with the amount of 0.1 M CaCl2-extractable Cu as a logarithmic function. On the other hand, the β-glucosidase activity at the end of the incubation.
CO2 Sorption and Dilation of Poly(methyl methacrylate)

Sorption of CO2 in poly(methyl methacrylate) at 35−200 °C and concurrent dilation of the polymer at 35−85 °C over a pressure range up to 50 atm were studied. Dissolution and Flory−Huggins interaction parameters for the gas in the polymer, not only in the rubbery state but also in the glassy state, were estimated by analyzing the sorption data above the glass transition temperature (Tg0, 105 °C). Isothermal glass transition of the polymer/gas system was observed on isotherms of sorption and dilation below Tg0. Partial molar volumes of sorbed CO2 determined from the sorption and dilation isotherms increased with increasing concentration to the glass transition concentration. These isotherms were also analyzed on the basis of extended dual-mode models of sorption and dilation. From obtained parameters of the dual-mode models, nonequilibrium properties such as mean size and number of microvoids for the pure polymer and the CO2-sorbed polymer in the glassy state were evaluated. The mean size, dependent upon CO.
Amendments for mitigation of odor emissions from dairy manure: Preliminary screening

Manure amendments have shown variable effectiveness in reducing odor. Twenty-two amendments were evaluated for dairy manure odor stored at 20oC for 3 d and 30 d. Amendments represented different classes of product including microbial, oxidizing agent, disinfectant, masking agent, and adsorbent. Each amendment was added to 2 kg dairy manure (1:1.7 urine:feces, 12% total solids) following recommended rates. In this preliminary screening, one sample (n=1) of each amendment was evaluated along with untreated manure (Control). Odor emissions from each amendment and Control was estimated twice by five qualified odor assessors (n=10) after each storage duration following an international standard method for Triangular Forced-Choice Olfactometry. Odor quality was quantified using a hedonic tone scale, a Labeled Magnitude Scale and ASTM methods for suprathreshold odor intensity and an odor character wheel for description. Odor emissions were significantly reduced at 30 d versus 3 d incubation (P<0.0001) with no amendment effective for both incubation times. Likewise, for all amendments tested, aging the manure slurry for 30 d reduced malodor and odor intensity by 10 to 105% (P<0.0001). A microbial digest/enzyme product (proprietary), disinfectant (hydrogen peroxide) and masking agent (Hyssopus officinalis essential oil) provided significant short-term control of odor (P <0.0001). However, after 30 d, only a proprietary microbial aerobic/facultative product and a proprietary mix of chemicals, both with weekly re-application, retained efficacy. Hedonic tone indicated an improvement to “slightly to moderately unpleasant” smell versus untreated manure for all amendments except clinoptilolite zeolite. Hedonic tone improvement was correlated with reduced manure odor intensity.
Morphological patterns of poly(N-isopropylacrylamide) derivatives synthesized with EGDMA, DEGDMA, and TEGDMA crosslinkers for application as thermosensitive drug carriers

A number of poly(N-isopropylacrylamide) (polyNIPAM) microgels were prepared with dimethacrylate cross-linking agents of various lengths, ether and ester groups in the backbone, and pendant vinylidine functionality. These materials were characterized by examining their morphological patterns using optical and scanning electron microscopy. When ethylene glycol dimethacrylate (EGDMA) was used as a cross-linking agent, microspheres of approximately 1 μm in diameter were obtained. Diethylene glycol dimethacrylate (DEGDMA) cross-linking resulted in relatively large spherical structures (1–5 μm) as well as spherical nanostructures (200 nm). Using triethylene glycol dimethacrylate (TEGDMA) resulted in spheres with diameters between 1 μm and 3 μm. The hydrodynamic particle diameter decreased with the increasing chain length of the dimethacrylate cross-linking agents. The turbidity increased with the temperature of transition points occurring at approximately 31–32°C confirming the thermosensitivity of the obtained polymeric structures.
On the Interaction of Electrons in Metals

The energy of interaction between free electrons in an electron gas is considered. The interaction energy of electrons with parallel spin is known to be that of the space charges plus the exchange integrals, and these terms modify the shape of the wave functions but slightly. The interaction of the electrons with antiparallel spin, contains, in addition to the interaction of uniformly distributed space charges, another term. This term is due to the fact that the electrons repell each other and try to keep as far apart as possible. The total energy of the system will be decreased through the corresponding modification of the wave function. In the present paper it is attempted to calculate this "correlation energy" by an approximation method which is, essentially, a development of the energy by means of the Rayleigh-Schrodinger perturbation theory in a power series of e'.
Membrane distillation properties of TiO2 ceramic membranes modified by perfluoroalkylsilanes

Abstract The tubular and planar TiO2 ceramic membranes were modified by grafting with perfluoroalkylsilanes (PFAS) molecules. Two types of PFAS were used for grafting process: 1H,1H,2H,2H-perfluorooctyltriethoxysilane (C6) and 1H,1H,2H,2H-perfluorotetradecyltriethoxysilane (C12). Studies showed that hydrophilic surface of titania ceramic membranes can be efficiently modified as a results of the proposed grafting method. Grafting efficiency of the tubular membranes was determined by measurement of liquid water entry pressure (LEPw), whereas grafting efficiency of planar membranes was verified by contact angle measurement. The contact angle values of the planar membranes are 130 and 140° for grafting with C6 and C12, respectively. The LEPw of the tubular membranes increased from 2 bar to 10 bar after modification by C12, whereas the LEPw values were constant at 2 bar when TiO2 membrane was modified by C6 molecules. It was found that water contact angle, LEPw, and water flux in the membrane distillation (MD).
Tropospheric methane in northern Finland: seasonal variations, transport patterns and correlations with other trace gases

Methane mixing ratios have been continuously observed at Pallas, Finland since winter 2004. The seasonal variation in monthly means was ca. 40 ppb, showing largest mixing ratios in winter and also high values during late summer. Examination of back-trajectories showed that the air masses with elevated methane mixing ratios arrived from continental Eastern and Central Europe while lowmethane mixing ratios were connected with Atlantic and Arctic air masses. During summer, air masses with highest mixing ratios arrived from Northwestern Russia indicating wetland sources, while the influence of southern emissions became more significant in winter. Methane was positively correlated with carbon dioxide and negatively correlated with ozone in winter. The average slope of the selected wintertime background hourly mean mixing ratios was 7.0 ± 1.2 ppb(CH4)/ppm(CO2). Nocturnal summertime low-altitude measurements above a local wetland source indicated slopes of about 10 ± 1 ppb(CH4)/ppm(CO2). The different slopes reflect the differences in emission parameters.
Characteristics of microencapsulated PCM slurry as a heat‐transfer fluid

The hydrodynamic and heat-transfer characteristics of slurry containing microencapsulated phase-change materials (MCPCMs) were investigated experimentally for use as a heat-transfer fluid. Pressure drop and local convective heat-transfer coefficients of the slurry flows in a circular tube with uniform heat flux were measured. Slurries consisting of octadecane (C{sub 18}H{sub 38}) contained in 2--10-{micro}m-dia. microcapsules and pure water were used. The particle volume fractions in the slurry were varied up to 0.3. Results showed that increases in particle volume fractions caused the slurry flow structure to change from turbulent to laminar, and the pressure-drop reduction of the slurry flow relative to a single-phase water flow was under the same flow-rate conditions. The heat-transfer performance of the slurry also depended on the change in flow structure. When the MCPCMs melted, the local heat-transfer coefficients for turbulent slurry flows increased relative to those for nonmelting slurry. This phenomenon was influenced by the MCPCM fraction, the degree of turbulence, and the heating rate at the tube wall. The experimental data will be useful in the design of thermal-energy transportation systems using MCPCM slurry.
Short-Term Exposure To Jp-8 Jet Fuel Results in Longterm Immunotoxicity

Chronic exposure to jet fuel has been shown to have adverse effects on human liver function, to cause emotional dysfunction, to cause abnormal electroencephalograms, to cause shortened attention spans, and to decrease sensorimotor speed. Due to the decision by the United States Air Force to implement the widespread use of JP-8 jet fuel in its operations, a thorough understanding of its potential effects upon exposed personnel is both critical and necessary. Exposure to potential environmental toxicants such as JP-8 may have significant effects on host systems beyond those readily visible (i.e., physiology, cardiology, respiratory, etc.); e.g., the immune system. Previous studies have shown that short-term, low concentration JP-8 exposure had significant effects on the immune system, which should have serious consequences for the exposed host in terms of susceptibility to infectious agents. If these alterations in immune function were long-lasting, it might also result in an increased likelihood of development and/or progression of cancer, as well as autoimmune disease. In the current study, mice were exposed for 1 hlday for 7 days to a moderate (1000 mg/m 3) and a high (2500 mg/m3) concentration of aerosolized JP-8 jet fuel to simulate occupational exposures. One to 28 days after the last exposure the mice were analyzed for effects of the exposure on their immune systems. It was observed that decreases in viable immune cell numbers and immune organ weights found at 24 h after exposure persisted for extended periods of time. Further, JP-8 exposure resulted in significantly decreased immune function, as analyzed by mitogenesis assays, which persisted for up to 4 weeks post-exposure. Thus, short-term exposure of mice to JP-8 jet fuel caused significant toxicological effects on the immune system, which were long-lasting and persistent. It appears that the immune system may be the most sensitive indicator of toxicological damage due to JP-8 exposure. Such long-term changes in immune status may have significant effects on the health of the exposed individual.