Miracle-dz/UniFAR-FTUs huggingface dataset:
INHIBITION OF POLYPHENOL OXIDASE IN BANANA, APPLE AND MUSHROOM BY USING DIFFERENT ANTI- BROWNING AGENTS UNDER DIFFERENT CONDITIONS

Fruit are highly perishable and maintain an active metabolism during the postharvest phase. Polyphenol oxidase or PPO (EC 1.14.18.1) is considered the enzyme responsible for quality deterioration and browning in different fruits during postharvest period. Since enzymatic browning causes deterioration of sensory and nutritional quality and affects appearance and organoleptic properties, inactivation of PPO is desirable for preservation of foods. The objective of this study was to evaluate the antibrowning (inhibition of polyphenol oxidase activity) effect of Cysteine (Cys) , Ascorbic acid (AA), citric acid (CA), sodium metabisulphite(SMB) alone or in combination, at three different pH (3.5,4 and 4.5) in banana (Musa paradisiaca L. var. Kanthali), apple (Malus pumila Mill. var. Ambri kashmiri), and mushroom (Agaricus bisporus). All the samples were mixed with Cys (100, 200 and 300 mg/kg.), AA(250,500 and 1000 mg/kg.), CA (250, 500 and 1000 mg/kg.) and SMB (100,200 and 300 mg/kg.) to assess their effect on PPO. PPO activity was analyzed spectrophotometrically at 420 nm (30 0 C). The most effective PPO inhibitors were AA and SMB and in combination with CA and Cys in all the samples tested. No significant differences were observed for PPO activity among concentrations of Cys and CA when both anti-browning agents were used alone or in combination and mixed with the samples.
The b 1Σ+ → X 3Σ− transition in PH: A measurement of the term energy, bond length, and vibrational frequency of a phosphinidene metastable

The (0,0), (1,1), and (2,2) vibrational bands of the weak, spin forbidden b 1Σ+ → X 3Σ− transition of the PH radical have been observed in a flowing afterglow of PH3 in He. The spectra yield the following constants for the upper b state: Te =(14 325.5±0.1) cm−1, Be =(8.587±0.003) cm−1, we =(2403.0±0.1) cm−1, Dv =(4.0±0.05×10−4) cm−1, αe =(0.0253±0.003) cm−1, and re =(1.4178±0.0004) A. The intensity distribution is consistent with the mixing of the b 1Σ+ state almost exclusively with the A 3Π state.
Method for Measuring Aqueous Solubilities of Organic Compounds

A new and simple method for the determination of the aqueous solubility expressed in grams per gram of solution of organic compounds is presented. A saturated aqueous solution is generated within a dialysis tubing at 25.0±0.2 o C. As demonstrated with cyclohexanol (water solubility around 3.8%) and anthracene (water solubility around 50 ppb) equilibrium is reached within 24 h. The concentration of the organic compounds in the aqueous solutions was determined via gas chromatography, which allows the measurement of samples that contain impurities or tend to degrade during measurement with high accuracy. Comparison of the solubility data for a series of organic compounds collected from the literature with the values obtained with the method described herein demonstrates its reliability. Thus, the method described allows the determination of water solubilities of organic compounds within a range from percent to the ppb region with a high accuracy and precision in a simple and efficient way
Effects Of Atmospheric Lead On Soil MicrobiotaIn Kuwait

The increase in human population is usually associated with increased waste production and by-products of urbanization. One such product of urbanization is heavy metals such as lead that at high concentrations have detrimental effects on human health as established previously. However, little is known about the effects of lead on the growth, activity and community of soil microbiota. For this purpose, the effects of lead on the microbiota of roadside soil samples collected from different distances from main roads in Kuwait were investigated. The addition of lead to soils decreased significantly (P<0.05) the counts and respiration of the total heterotrophic bacteria in particular in soils harbored lower concentrations of lead. Furthermore, the identification of soil bacteria showed the dominance of Gram-negative bacteria with high potentials to tolerate multiplicity of heavy metals where the order of increasing toxicity of heavy metals on tested bacteria was lead < chromium < aluminium < cobalt < nickel < mercury < cadmium. Moreover, based on 16S-RFLP analyses, it was demonstrated that soils containing higher concentrations of lead harboured less diverse bacterial communities. Results suggested that changes in soil microbiota are attributed to atmospheric lead apparently originated from car emissions.
A comparative simulation analysis of propane dehydrogenation in composite and microporous membrane reactors

Propane dehydrogenation has been simulated for a composite membrane reactor and a microporous membrane reactor using plug-flow reactor models, in which both were packed with Pt/Al2O3 catalyst in the tube-side. The reaction kinetics employed in the analysis were obtained from experimental data produced in an integral fixed bed reactor with the same catalyst. Comparative studies were carried out to analyse the performances of reactors containing the different membranes in terms of contact time, flow pattern and flow rate of sweep gas, and pressure. In general, the composite membrane reactors gave the better performance for all cases investigated. © 2002 Society of Chemical Industry
Photocrosslinking System Using Highly-Functionalized Epoxy Crosslinkers Having Degradable Property

Multifunctional crosslinkers having two, three, four and six functionalities were synthesized using a convergent method and were applied to a photocrosslinking system having thermally degradable properties. The multifunctional crosslinkers contained epoxy units and tertiary ester linkages. When the blended films of epoxides/poly(p-vinylphenol) with a photoacid generator were irradiated and followed by baking at relatively lower temperatures (<100 °C), the films became insoluble in solvents. Heating conditions strongly affected the insoluble fraction of the blends. Insoluble fraction of the blended films increased with the number of the epoxy unit of a molecule. The crosslinked films became soluble after prolonged bake at relatively higher treatments (>120 °C). The reaction pathway of the blended system was studied by in situ FT-IR measurements.
Calculating the Keldysh adiabaticity parameter for atomic, diatomic, and polyatomic molecules

A numerical model is presented to determine the Keldysh adiabaticity parameter for the interaction of an intense laser with a polyatomic molecule. The adiabaticity parameter is a guide to determining whether the ionization process is in the field or multiphoton ionization regime. The adiabaticity parameters are compared for potentials including the simple zero-range potential, the Coulomb potential, an atomic potential (Xe), a diatomic (N2) molecular potential, and a polyatomic (C6H6) molecular potential. It is demonstrated that the Coulomb potential is approximately equal to the atomic and diatomic potentials and differs from the zero-range potential employed in the Keldysh model in a way which is predominantly dependent upon the ionization potential. Both simple models substantially overestimate the adiabaticity parameter for C6H6 at all field strengths and at fields above 1.25 V/A both simple models become completely unphysical. This is because barrier suppression ionization is predicted to occur for b.
Polymerized Ionic Liquid Block and Random Copolymers: Effect of Weak Microphase Separation on Ion Transport

A series of polymerized ionic liquid (PIL) block and random copolymers were synthesized from an ionic liquid monomer, 1-[(2-methacryloyloxy)ethyl]-3-butylimidazolium bis(trifluoromethanesulfonyl)imide (MEBIm-TFSI), and a nonionic monomer, methyl methacrylate (MMA), at various PIL compositions with the goal of understanding the influence of morphology on ion transport. For the diblock copolymers, the partial affinity between the PIL and PMMA blocks resulted in a weakly microphase-separated morphology with no evident long-range periodic structure across the PIL composition range studied, while the random copolymers revealed no microphase separation. These morphologies were identified with a combination of techniques, including differential scanning calorimetry, small-angle X-ray scattering, and transmission electron microscopy. Surprisingly, at similar PIL compositions, the ionic conductivity of the block copolymers were ca. 2 orders of magnitude higher than the random copolymers despite the weak microphase.
Block Copolymer Surface Reconstuction: A Reversible Route to Nanoporous Films

Thin films of block copolymers have been used as templates and scaffolds for the fabrication of arrays of nanostructured materials. In general, a chemical modification of the film or the removal of one of the components by photodegradative methods is required to produce a nanoporous film that serves as a template or scaffold. Here, however, the preferential interaction of one of the components with a solvent is shown to produce a reconstruction of the block copolymer film that, upon drying, leads to the generation of a nanoporous template. The area density of the pores is identical to that of the original copolymer thin film. Since no chemical reactions occurr, the process is fully reversible. Upon heating the copolymer film above its glass‐transition temperature, mobility is imparted to the copolymer and the original copolymer film with oriented domains is recovered. The film reconstruction significantly simplifies the generation of nanoporous templates.
Thiol-capped ferromagnetic Au nanoparticles investigated by Au L3 x-ray absorption spectroscopy

Different dodecanethiol capped Au nanoparticles (NP) with similar sizes (∼2nm) but different ferromagnetic signals at room temperature have been investigated by means of x-ray absorption spectroscopy at the Au L3-edge. The reversion of the x-ray magnetic circular dichroism signal with the change of sign of the external applied magnetic field confirms the location of the magnetism at the Au atoms. In comparison with the Au foil, all the samples present accentuated white lines at the x-ray absorption near-edge structure (XANES) indicating generation of 5d holes in the Au atoms located at surface of the NPs as consequence of a localized charge transfer from the Au surface atoms to the S atoms of the capping agent. XANES spectra reflect differences among the electronic structure of the Au NPs which are compared with the observed different macroscopic magnetic signals.
Surface graft copolymerization of acrylic acid onto corona-treated poly(ethylene terephthalate) fabric

Acrylic acid (AA) was grafted onto the surface of poly(ethylene terephthalate) (PET) fabric after having short-time corona-discharge treatment (CDT) in an atmosphere in the presence of the initiator. The effect of N,N-dimethylformamide (DMF) pretreatment time, CDT time, graft copolymerization time and temperature, concentration of AA, and the content of initiator on graft yield of PET fabric was discussed.
Antihistaminic effect of terfenadine: A new piperidine‐type antihistamine

The antihistaminic effect of terfenadine was studied in the isolated guinea pig ileum, histamine skin wheals in guinea pigs and monkeys, and i.v. histamine‐induced death in guinea pigs. In the guinea pig ileum, terfenadine, 1 × 10−7 M, shifted the histamine dose‐response curve to the right in a parallel fashion without affecting the dose‐response curve of acetylcholine and barium chloride. However, as the dose of terfenadine was increased (3.16 × 10−7 and 1 × 10−6 M) the histamine dose‐response curves were displaced to the right with a depression of the maximum response and a reduction of the slope. Thus an unsurmountable type of antagonism was observed. Acetylcholine was also antagonized in a similar fashion by these two concentrations. In contrast, terfenadine appeared to displace the barium chloride dose‐response curve to the right in a parallel fashion. At 0.4 and 0.8 mg/kg p.o. , terfenadine shifted the histamine skin wheal dose‐response curves to the right in a parallel fashion, but at 1.6 to 6.4 mg/kg, terfenadine antagonized the histamine wheal dose‐response curves with a depression of the maximum and the slope of the curve. These results were also similar to those of cyproheptadine but were different from those of chlorpheniramine, which produced parallel shifts. In monkeys, terfenadine produced a substantially greater effect on the histamine wheal than did chlorpheniramine (both administered at 30 mg/kg p.o.). Terfenadine also completely protected against i.v. histamine‐induced death in guinea pigs. Terfenadine produced no atropine‐like effect against pilocarpine‐induced salivation in rabbits, no demonstrable histamine H2 antagonism, no antiserotonin activity, no α or β antagonism, and no untoward cardiovascular effects. Most significantly, terfenadine had no overt central nervous system (CNS) effects in mice, rats, guinea pigs, or monkeys; whereas chlorpheniramine produced tremors and convulsions in mice and monkeys when tested at much lower doses than those used for terfenadine. It is concluded that terfenadine is an effective and specific antihistaminic compound with the potential advantage of a lack of CNS sedative effects.
Synthesis, Characterization, and Crystal Structures of a Novel [Zn3(bba)6(3-pic)2] Complex (bba = 2-Benzoylbenzoat, 3-pic = 3-Picoline)

A novel trinuclear hekzakis(μ6-2-benzoylbenzoato-O,O′)-bis(3-picoline)-tri-zinc(II) complex, [Zn3(bba)6(3-pic)2] has been synthesized and characterized by elemental analysis, Fourier-transform infrared (FT-IR), ultraviolet/visible (UV/Vis), and mass spectroscopy, thermal methods, and single-crystal x-ray diffraction. The three Zn(II) centers are in two different coordination environments. The central Zn(II) is in a distorted octahedral geometry, while the two terminal Zn(II) centers adopt a distorted tetrahedral geometry. The central and the terminal metal centers are connected through tri μ-2-benzoylbenzoato-O,O′ bridges. The crystal packing of the trinuclear complex is stabilized by C–H···π interaction between bba ligands. The characteristics of the carboxylate anions with typical υ(OCO)asym and υ(OCO)sym values are 1594 and 1368 cm−1, respectively.
Adsorption of Water Vapor by Poly(styrene) Sulfonic Acid Sodium Salt—Isothermal and Isobaric Adsorption Equilibria

Air-conditioning and dehumidifying systems by sorption on solids are of great interest, particularly in humid climates, because they allow a reduction of thermal loads, which minimizes denergy consumption to maintain the indoor setpoint temperature and the use of HFC. Recent studies have shown that hydrophilic polymers, such as sulfonic polymers, could have a very high performance in water adsorption from air. The aim of this study was to characterize the water vapor adsorption properties of a completely sulfonated and mono-sulfonated poly(styrene) sulfonic acid sodium salt (PSSASS) and to elucidate the mechanism of adsorption on these materials. Adsorption isotherms have been determined by thermal gravimetric analysis (TGA) between 298 K and 317 K for pressures ranging from 0.01 to 4.5 kPa. They have type II of the IUPAC classification and a small hysteresis loop was observed between adsorption and desorption processes only for the mono-sulfonated sample. Water content was up to 80 w% at 80% relative humidity. Adsorption isotherms have been well fitted with the Frenkel-Halsey-Hill model(so-called FHH model). Adsorption-desorption isobars have been determined by TGA under 3.7 kPa in the temperature range of 298 K-373 K. They have shown that these polymers could be completely regenerated by heating at 313 K under humidified air. No degradation of the adsorption properties has been observed after several regenerations. Adsorption enthalpies and entropies have been deduced from the Clapeyron equation and from differential scanning calorimetric (DSC) measurements. A good agreement was found. Our results suggested that the adsorption of water on these polymers occurs in two steps: formation of water aggregates on sodium cations of sulfonated groups and then capillary condensation with a structural modification of the polymer, which decreased as sulfonation degree increased.
Synergistic Interaction of Dyes and Semiconductor Quantum Dots for Advanced Cascade Cosensitized Solar Cells

A new procedure for the cosensitization with quantum dots (QDs) and dyes for sensitized solar cells is reported here. Cascade cosensitization of TiO2 electrodes is obtained by the sensitization with CdS QDs and zinc phthalocyanines (ZnPcs), in which ZnPcs containing a sulfur atom are specially designed to produce a cascade injection by direct attachment to QDs. This strategy causes a double synergetic interaction. This is the differentiating point of cascade cosensitization in comparison with other approaches in which dyes with conventional functionalization are anchored to TiO2 electrodes. Cosensitization produces a panchromatic response from the visible to near‐IR region already observed with other sensitization strategies. However, cascade cosensitization produces in addition a synergistic interaction between QDs and dye, that it is not merely limited to the complementary light absorption, but dye enhances the efficiency of QD sensitization acting as a passivating agent. The cascade cosensitization concept is demonstrated with using [Co(phen)3]3+/2+ redox electrolyte. The TiO2/CdS QD‐ZnPc/[Co(phen)3]3+/2+ sensitized solar cell shows a large improvement of short‐circuit photocurrent and open‐circuit voltage in comparison with samples just sensitized with QDs. The advent of such cosensitized QD‐ZnPc solar cells paves the way to extend the absorbance region of the promising QD‐based solar cells and the development of a new family of molecules designed for this purpose.
Comparison of single and multi-analyte methods based on LC-MS/MS for mycotoxin biomarker determination in human urine

The performances of four LC-MS/MS methodologies for determination of up to eight mycotoxin biomarkers in human urines were compared by involving three laboratories that analysed common urine samples spiked at two levels of each biomarker. Each laboratory received a calibration solution, spiked urines and the corresponding unspiked urine. The two spiking levels for each biomarker were chosen by considering the levels naturally occurring in human urines and the limits of quantification of the LC-MS/MS methodologies used by the participating laboratories. The results of each laboratory were evaluated for their z-score values. The percentage of satisfactory z-scores (| z | < 2) were: 100% for deoxynivalenol, de-epoxy deoxynivalenol, aflatoxin M1, β-zearalenol and zearalenone, 87% for α-zearalenol, 50% for ochratoxin A and 42% for fumonisin B1. Good method performances were obtained for most biomarkers at the levels tested in this study, as demonstrated by the overall percentage of satisfactory z-scores for al.
New supplemental activator for lead isotope analysis using TIMS

169 and (2) 204Pb is used as the denominator for lead isotope ratios (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb), although its low abundance results in poor reproducibility, especially in the case of small samples. This disadvantage can be overcome by using the double-spike (DS) method (Dodson, 1963; Compston and Oversby, 1969). However, duplicate analysis of a single sample requires a long period of data acquisition using single-collector TIMS. This limitation has largely been overcome by the development of multi-collector TIMS, which has drastically reduced the measurement time (Hamelin et al., 1985; Woodhead et al., 1995). A remaining challenge is to optimize the ionization efficiency of Pb when using the DS method, as this would extend the lower limits of sample volume necessary for Pb isotope measurements. The use of a silica-gel activator with phosphoric acid results in the enhanced Pb ion beam intensity (Cameron et al., 1969) and is effective in terms of limiting instrumental mass fractionation during analysis. Gerstenberger and Haase (1997) reported a stable 208Pb ion beam of 3– 4 × 10–11 A for 10 ng Pb of the NBS standard using suspended colloidal silica. Kuritani and Nakamura (2002) obtained 2–3 × 10–11 A of 208Pb for ~10 ng Pb, 1–2 × 10–11 A for ~5 ng, and 0.4–0.6 × 10–11 A for ~1 ng. Nohda (1999) and Kani and Nohda (2002) proposed a method using fused silica-gel to obtain a stable Pb ion beam with TIMS; however, sample sizes needed were larger than 100 ng, unsuitable for analyses of low abundance natural samples. The aim of the present study is to enhance Pb ion beam intensity and to develop a method for measuring Pb isoNew supplemental activator for lead isotope analysis using TIMS
ANALYSIS OF HEAVY METALS AND ORGANIC POLLUTANTS FROM SOME DANUBE RIVER FISHES

This paper presents an analysis of pollution with heavy metals (cadmium, cooper, zinc, lead) and pesticides: lindan, dichlorodiphenyldichloroethylene (DDE), dichlorodiphenyldichloroethane (DDD), dichlorodiphenyltrichloroethane (DDT) from four fish species from Danube River: Alosa pontica, Cyprinus carpio, Abramis brama and Esox lucius. The concentrations of heavy metals were determined with an atomic absorption spectrophotometric method (air / acetylene flame) and the concentrations of pesticides were determined with a gas chromatograph equipped with an electron capture detector (ECD). Rezumat Lucrarea prezintǎ o analizǎ a poluǎrii cu metale grele (cadmiu, cupru, zinc, plumb) si pesticide (lindan, DDE, DDD, DDT) din patru specii de pesti din Dunǎre: Alosa pontica, Cyprinus carpio, Abramis brama si Esox lucius. Concentraţia metalelor grele a fost analizatǎ cu un spectometru de absorbţie atomicǎ cu flacarǎ aer/acetilenǎ iar pesticidele au fost analizate folosind o metodă gaz cromatografică cu detector cu capturǎ de electroni.
Development of a modified copper-cadmium reduction method for rapid assay of total nitric oxide

The biomolecule, nitric oxide (NO) is short lived and is converted to two stable products—nitrite (NO2) and nitrate (NO3). NO3 can be measured by colorimetric procedure involving enzymatic conversion to NO2 and by HPLC. But these methods, though sensitive and specific, require expensive reagents or equipment. Reduction of NO3 to NO2 by copper-coated cadmium granules is a popular method devised by Cortas and Wakid (Clin. Chem., 1990, 36, 1440), but it takes 120 min. Our aim of this study is to modify the Cortas and Wakid method for rapid reduction of NO3 to NO2 for total NO estimation in serum. After reduction, NO2 is estimated by Griess reaction. As per our results, complete reduction of NO3 could be achieved by both the methods, but it took only 5 min by our method. Standard graphs were linear by both of the methods. Factors were found to be 143.4 and 196.7 by the Cortas and Wakid method and by our method, respectively. Recovery of NO2 from NO3 was found to be 105% and 106%, respectively. We measured total NO2 in sixteen sera by both the methods and our method's coefficient of correlation was found to be 0.9924. Our method is comparable to that of Cortas and Wakid for complete reduction of NO3 with the greatest advantage of decrease in the time span from 120 to 5 min. This is due to our development of an increased copper coating method on cadmium granules. Our rapid method saves much time for total NO estimation.