Miracle-dz/UniFAR-FTUs huggingface dataset:
Photocatalytic Activities of Graphitic Carbon Nitride Powder for Water Reduction and Oxidation under Visible Light

Graphitic carbon nitride (g-C3N4) with a band gap of 2.7 eV is studied as a nonmetallic photocatalyst for H2 or O2 evolution from water under ultraviolet (UV) and visible light. The g-C3N4 catalyst exhibits activities for water reduction into H2 or water oxidation into O2 in the presence of a proper sacrificial electron donor or acceptor, respectively, even without the need for precious metal cocatalysts. When bis(1,5-cyclooctadiene)platinum complex [Pt(cod)2] (a nonionic complex) is used as a precursor of Pt cocatalyst instead of H2PtCl6 (an ionic complex), enhanced H2 evolution activity is acquired. This difference in activity is primarily due to the better dispersion of Pt nanoparticles on g-C3N4, which is considered to originate from the better access of Pt(cod)2 to the g-C3N4 surface, as compared to that of H2PtCl6 in the preparation process. Unmodified g-C3N4 produces O2 from an aqueous silver nitrate solution upon UV irradiation (λ > 300 nm), although N2 release due to self-decomposition of g-C3N4 .
Oral Bioavailability of Polychlorinated Dibenzo-p-Dioxins/Dibenzofurans in Industrial Soils

ABSTRACT In this study, the oral bioavailabilities of numerous 2,3,7,8-PCDD/F congeners were evaluated in soil samples from an industrial site. The purpose of this study is several-fold: (1) to compare the soil bioavailability results of the different PCDD/F congeners; (2) to evaluate the consistency of the bioavailability results with those obtained in an in vitro bioaccessibility study with simulated GI tract fluids; and (3) to develop quantitative bioavailability measurements that are appropriate for use in a health risk assessment for this site. Soil samples containing PCDD/F toxic equivalent (TEQ) concentrations ranging from 0.53–45.2 ng/g were administered to female Sprague Dawley rats via oral gavage. Reference formulations of PCDD/Fs were administered intravenously or by oral gavage. The overall relative bioavailability of PCDD/Fs in the soil samples on a TEQ basis ranged from 17 to 51%, with a mean of 38%. The results of the in vitro bioaccessibility study were consistent with the bioavailability results (mean extracted TEQ of 22%). Because of the clear relationship between increasing chlorination and decreasing bioavailability and bioaccessibility observed in this study, we suggest that simply extrapolating results from one congener to another may be associated with a high degree of uncertainty.
Charakterisierung mechanolytisch abgebauter Pektinpräparate

Beim Schwingmahlabbau von lufttrockenen Pektinpraparaten bleibt unter der Bedingung einer hydrolytischen Spaltung der α(14)-glykosidischen Bindungen der Verseterungsgrad konstant. Die zu Beginn vorliegende statistische Verteilung der freien und der veresterten Carboxylgruppen wird unverandert beibehalten. Die Affinitat der Carboxygruppen zu Ca2+-Ionen andert sich erst im Bereich der vermehrten Buildung von oligomeren Abbauprodukten. Die von der Kettenlange abhangige Grenze einer deutlichen Abschwachung der Ionenbindung verschiebt sich mit zunehmendem Veresterungsgrad zu hoheren Viskositatszahlen bzw. Polymerisationsgraden. Mit fortschreitender Mechanolyse wird auserdem eine charakteristische Vereinheitlichung in der Molmassenverteilung gelchromatographisch nachgewiesen. Eine Anreicherung der die D-Galakturonsaure trotz intensiver Reingingung der Pektinpraparate noch begleitenden neutralen Saccharide tritt unabhangig von der Mahldauer bzw. dem Abbaugrad jeweils in den niedermolekularen und in den hochmolekularen Fraktionen der Gelchromatogramme auf. On vibration grinding of air-dried pectin preparations with a hydrolytic cleavage of the α(14) glycosidic linkage the degree of esterification remains constant. The random distribution of free and of esterified carboxyl groups remains unchanged. The affinity of the carboxyl groups to Ca2+ ions is changing only when oligomers are formed. The limit of a significant weakening of the ionic linkage being dependent on the chain lenght, will be shifted to higher viscosity numbers and to higher degrees of polymerization, respectively, with an increasing degree of esterification. Moreover, at a proceeding mechanolysis there is a characteristic decrease of the width of the distribution of molecular weights. This could be proved by gel chromatography. An enrichment of the neutral saccharides still present in the pectin preparations together with the D-galacturonic acid in spite of an intense purification, takes place independently of the grinding time and of the degree of degradation, respectively, as well in the low-molecular as in the high-molecular fractions of the gel chromatograms.
Radiation damage in polyethylene as studied by electron spin resonance

The electron spin resonance method was employed to study the nature, concentration and kinetics of the disappearance under varying conditions of radicals produced in polyethylene by fast electron irradiation at 77°K. The predominant radical species at 77°K is the alkyl radical —CH2—ĊH—CH2—. On being warmed to room temperature it disappears rapidly, revealing a more stable unidentified radical. The kinetics of the decay at room temperature of both radicals was observed. Their stabilities were found to vary in polyethylene samples of differing physical and chemical properties. G values for these radicals are given. Comparison was made with spectra obtained under similar conditions with two pure paraffins and a pure olefin to evaluate the effect of crystallinity branching, molecular weight and unsaturation. In the olefin there is evidence for a build-up of allyl radicals due to the encounter of an alkyl radical with main chain unsaturation. This supports the view that alkyl radicals are mobile, and cross-linking occurs when two such radicals meet.
Magnetoresistance effect of La0.72Ca0.25MnOz/YBa2Cu3Oy/La0.72Ca0.25 MnOz trilayered films

The magnetoresistance (MR) effects of La0.72Ca0. 25MnOz (LCMO) magnetic films and LCMO/YBa2Cu3Oy (YBCO)/LCMO trilayered films were studied. The LCMO films have an MR ratio of −4% when applying 1 T at 77 K and this value is independent of the film thickness from 1500 to 4500 A. In contrast to that, the MR ratio for LCMO/YBCO/LCMO films depends on the thickness of the YBCO layer and is more than 1.5 times as large as that for LCMO films when the thickness of the YBCO layer is less than 2500 A. These results imply that the magnetic spin interaction between the two LCMO layers may exist through the normal‐conductive state YBCO layer.
Synthesis and properties of monolayer graphene oxyfluoride

Covalent bond-forming reactions can be used to tailor the properties of graphene, aiming at electronic band structure engineering and surface functionalization. We present a novel and easy method for the production of chemically modified monolayer graphene based on the electrochemical intercalation of graphite, that could be used for adding various functional groups to the graphene lattice. Oxy-fluorinated graphene layers have been produced and fully characterized in terms of their chemical composition and functionalization. Moreover, Raman spectroscopy allows ready discrimination between monolayers and few-layers, and field-effect devices have been fabricated in order to study the transport properties of monolayer graphene oxyfluoride. Interesting conduction mechanisms such as two dimensional Mott variable range hopping and colossal negative magneto-resistance are observed, making this novel material suitable for both fundamental research and graphene-based applications.
Manganese as a Replacement for Magnesium and Zinc: Functional Comparison of the Divalent Ions

Divalent manganese, magnesium, and zinc fill unique roles in biological systems, despite many apparently similar chemical properties. A comparison of the liganding properties of divalent manganese, magnesium, and zinc has been made on the basis of data on crystal structures (from the Cambridge Structural Database and the Protein Databank) and molecular orbital and density functional calculations. The distribution of coordination numbers for divalent manganese in crystal structure determinations, and the identities of ligands, have been determined from analyses of data derived from the structural databases. Enthalpy and free energy changes for processes such as loss of water or ionization of water from hydrated cations have been evaluated from computational studies. The energy penalty for changing the hexahydrate of divalent manganese to a pentahydrate with one water molecule in the second coordination shell is intermediate between the high value for magnesium and the low value for zinc. The preferred coor.
Toward a Physically Sound Structure−Activity Relationship of TiO2-Based Photocatalysts

The morphological (analyzed by N2-Brunauer−Emmett−Teller, transmission electron microscopy, X-ray diffraction), surface chemical (analyzed by NH3-temperature programmed desorption), and opto-electronic properties (analyzed by time resolved microwave conductivity measurements (TRMC)) of nanoparticulate anatase TiO2 (Hombikat, Sachtleben) were modified by calcination at temperatures ranging from 200 to 800 °C. Upon calcination the primary particle size and the crystallinity increase, strongly influencing the performance in the degradation of methylene blue. It is striking that for the investigated set of samples the rate versus primary particle diameter goes through a minimum. This is explained by the equation of the kinetic rate constant, keff = k[OH][h+]; [OH] decreases continuously as a function of increasing particle size, which is overcompensated by a strong increase in [h+] for particle sizes above ∼15 nm. The latter is the result of an increasing crystal quality of the anatase phase induced by calcination, as derived from the TRMC measurements. Implications for the rational design of improved photocatalysts are discussed
Effect of Field Strength on Electrooptical Properties of Low-Molecular Weight and Polymer Liquid Crystals

The influence of a strong electric field on isotropic melts of 6-cyanobiphenyl and comb-shaped polyacrylate with side mesogenic groups was investigated. It was established that the electric field induces the isotropic—nematic phase transition in melts of these compounds. A relaxation process was discovered that destroys the nematic ordering induced in substances by electric fields. It was found that the relaxation time τ of the orientational order parameter is proportional to the square of electric field strength. For comb-shaped polymer liquid crystals, the time of transition from the nematic to the isotropic phase is several orders longer then that for low-molecular liquid crystal.
Paste Electrode Based on Short Single-Walled Carbon Nanotubes and Room Temperature Ionic Liquid: Preparation, Characterization and Application in DNA Detection

A paste electrode (SWNT&RTIL PE) has been prepared using carboxylic group-functionalized short single-walled carbon nanotubes (SWNTs) mixed with 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6, one kind of room temperature ionic liquid, RTIL). Its electrochemical behavior was investigated by cyclic voltammetry and electrochemical impedance spectroscopy in comparison with the paste electrode using mineral oil as a binder. Results highlighted the advantages of the paste electrode: not only higher conductivity, but also lower potential separation (ΔEp), higher peak current (ip) and better reversibility towards dopamine (DA), methylene blue (MB) and K3[Fe(CN)6]. The SWNT&RTIL PE could be used to detect the number of guanine bases and adenine bases contents in per mol oligonucleotides according to the current response in the range of 0.05–2.0 nM. Based on the current response of guanine bases, oligonucleotides could be detected sensitively in the B–R buffer solution with a detection limit of 9.9 pM. The heterogeneous electron transfer rate constant (ks) of guanine bases contents in the oligonucleotides was investigated and its value was 0.90 s−1. In essence the SWNT&RTIL PE showed high sensitivity, reliability, stability and reproducibility for the detection of DNA.
Thermally stable polyureas and poly(urea‐imide)s containing zinc and nickel napthtrien complexes

Two new napthtrien metal complexes, MNapth2trien; where M = Zn and Ni, were synthesized and used for the synthesis of metal-containing polyureas and poly(urea-imide)s. MNapth2trien underwent polymerization reaction with two diisocyanates, namely, 4,4′-diphenylmethane diisocyanate and isophorone diisocyanate to yield polyureas. Poly(urea-imide)s were obtained by the synthesis of metal-containing isocyanate-terminated polyurea prepolymers from the reaction between MNapth2trien and excess diisocyanates, which could then undergo further reaction with different dianhydrides. The dianhydrides used were pyromellitic dianhydride and benzophenone-3,3′,4,4′-tetracarboxylic dianhydride. The polymers were characterized by infrared, nuclear magnetic resonance, elemental analysis, X-ray diffraction, solubility, and viscosity. Glass transition temperature of the polymers was obtained from differential scanning calorimetry and dynamic mechanical thermal analysis. Thermal stability of polymers was studied by thermogravimetric analysis in air. It was found that the resulting metal-containing polymers exhibited good thermal stability. Initial decomposition temperatures of the polymers depend on the amount of MNapth2trien in the polymer composition. Char yields of metal-containing poly(urea-imide)s are higher than those of metal-containing polyureas. Most metal-containing polymers show good solubility in organic solvents. Shore D hardness test indicates that metal-containing poly(urea-imide)s are hard materials. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Projecting Active Contours with Diminutive Sequence Optimality

Active contours are widely used in image segmentation. To cope with missing or misleading features in image frames taken in contexts such as spatial and surveillance, researchers have commence various ways to model the preceding of shapes and use the prior to constrict active contours. However, the shape prior is frequently learnt from a large set of annotated data, which is not constantly accessible in practice. In addition, it is often doubted that the existing shapes in the training set will be sufficient to model the new instance in the testing image. In this paper we propose to use the diminutive sequence of image frames to learn the missing contour of the input images. The central median minimization is a simple and effective way to impose the proposed constraint on existing active contour models. Moreover, we extend a fast algorithm to solve the projected model by using the hastened proximal method. The Experiments done using image frames acquired from surveillance, which demonstrated that the proposed method can consistently improve the performance of active contour models and increase the robustness against image defects such as missing boundaries.
Cadmium uptake and growth inhibition in water hyacinths: effects of nutrient solution factors

Abstract Cadmium (Cd) uptake and distribution in water hyacinth plants were studied in relation to growth and modifications in different solution factors (Cd concentration, Ca concentration and pH). Cadmium accumulation rates by roots were two to five times higher than those by leaves (including petioles) when Cd concentrations in the solution ranged from 0 to 10 ppm. The increase in the external concentration of Cd resulted in increased accumulation rates both by leaves and roots. The total content of Cd in roots was higher than that in leaves only when external concentrations of Cd were lower than 1.5 ppm. Cadmium reduced relative growth rates in both plant parts, particularly in roots. Cadmium concentrations that yielded growth reduction of 50% were 1.5, 9.9, and 5.8 ppm for roots, leaves and whole plant, respectively. Increased pH or reduced concentration of calcium (Ca) in the nutrient solution resulted in increased accumulation of Cd in roots, without affecting Cd accumulation in leaves.
Nonylphenol polyethoxy carboxylate metabolites of nonionic surfactants in U.S. paper mill Effluents, Municipal sewage treatment plant effluents, and river waters

Because of their weakly estrogenic properties, interest in nonylphenol polyethoxylates and their carboxylated metabolites is resurging. To assess their occurrence in surface waters impacted by municipal and industrial effluents, an analytical method was developed for the quantitative determination of nonylphenol polyethoxy carboxylate (NPEC) metabolites of nonylphenol polyethoxylate surfactants in paper mill effluents, municipal sewage treatment plant effluents, and river waters. Strong anion exchange solid phase extraction disks were used for NPEC isolation from aqueous samples, and NPEC elution from the disk is simultaneously combined with derivatization. Extracts were analyzed by gas chro matography and positive mode chemical ionization mass spectrometry. The detection limit of the method ranged from 0.2 μg/L for NP1EC to 2 μg/L for NP4EC. The total concentration of NPECs in a group of paper mill and municipal sewage effluents ranged from below detection to 1300 μg/L. The total concentration of NPECs i.
Preparation and Characterization of a Calcium Phosphate Ceramic for the Immobilization of Chloride-containing Intermediate Level Waste

Attention has recently been given to the immobilization of special categories of radioactive wastes, some of which contain high concentrations of actinide chlorides. Although vitrification in phosphate glass has been proposed, this was rejected because of the high losses of chloride. On the basis of non-radioactive and, more recently, radioactive studies, we have shown that calcium phosphate is an effective host for immobilizing the chloride constituents [1]. In this instance, the chlorine is retained as chloride, rather than evolved as a chlorine-bearing gas. The immobilized product is in the form of a free-flowing, non-hygroscopic powder, in which the chlorides are chemically combined within the mineral phases chlorapatite [Ca5(PO4)3Cl] and spodiosite [Ca2(PO4)Cl]. Data from studies on non-radioactive simulated waste consisting of a mixture of CaCl2 and SmCl3, and radioactive simulated waste composed of CaCl2 with PuCl3 or PuCl3 and AmCl3, are presented and compared. The XRD data confirm the presence of chlorapatite and spodiosite in the non-radioactive and radioactive materials. The durability of all specimens was measured with a modified MCC-1 test. Releases of Cl after 28 days were 1.6 x 10-3 g m-2 for the non-radioactive specimens and 7 x 10-3 g m-2 for the Pu-bearing specimens. Releases of Camore » after 28 days were 0.3 x 10-3 and 2.0 x 10-3 g m-2 for the non-radioactive composition and the Pu composition, respectively, whilst release of Pu from the radioactive specimens was lower for the mixed Pu/Am specimen at 1.2 x 10-5g m-2. The release of Am from the mixed Pu/Am composition was exceptionally low at 2.4 x 10-7 g m-2. Overall, the release rate data suggest that the ceramics dissolve congruently, followed by precipitation of Sm, Pu and Am as less soluble phases, possibly oxides or phosphates. The differences in behaviour noted between non-radioactive and radioactive specimens are interpreted in terms of the crystal chemistry of the individual systems. « less
INDUCTION OF FREE RADICALS IN DNA BY PROFLAVINE AND VISIBLE LIGHT: INFLUENCE OF OXYGEN AND IONIC STRENGTH

Abstract—The photosensitization of native DNA is observed as an induction of free radicals in the DNA moiety of proflavine‐DNA complexes. The intensity of the electron paramagnetic resonance spectra (at 77 K) is a measure of the number of free radicals present in frozen solutions of DNA‐proflavine complexes after irradiation with visible light (Λ > 320 nm). In the absence of O2, the photosensitization is significant but very low; it increases slightly with increasing NaCl ionic strength; it appears to be due to intercalated dye molecules and the qualitative analysis of the spectra obtained shows that mainly thymidine is involved. The reaction measured after saturation with O2 is the same as the reaction in air but is quantitatively higher; the free radicals observed are peroxides. This induction of free radicals appears to be due to the intercalated dye molecules, each molecule acting independently. The important observation is a very sharp and large (around a hundred‐fold) increase in the photosensitizing efficiency of the bound dye molecules occurring in NaCl between μ, # 0–25 and μ= 0–5 and in MgCl2 between μ# 0–01 and μ=0–1.
Handbook for Computer Security Incident Response Teams (CSIRTs)

Abstract : This document provides guidance on the generic issues to consider when forming and operating a computer security incident response team (OSIRT). In particular, it helps an organization to define and document the nature and scope of a computer security incident response (OSIR) service, which is the core service of a CSlRT. The document discusses the functions that make up the service; how those functions interrelate; and the tools, procedures, and roles necessary to implement the service. This document also describes how OSIRTs interact with other organizations and how to handle often sensitive information. In addition, operational and technical issues are addressed, such as equipment, security, and staffing considerations. This document is intended to provide a valuable resource to both newly forming teams and existing teams whose services, policies, and procedures are not clearly defined or documented. The primary audience for this document consists of managers responsible for the creation or operation of a CSlRT or a CSlR service. It can also be used as a reference for all OSIRT staff, higher-level managers, and others who interact with a OSIRT.
Hydrothermal Growth of Vertical ZnO Nanorods

Vertically aligned, single crystalline ZnO nanorods with a high packing density and diameter of ∼ 60 nm have been successfully synthesized via a low-temperature hydrothermal route on glass substrates pre-deposited with a ZnO seeding layer. The seeding layer exhibits an epitaxial effect on the growth and alignment of the ZnO nanorods. This epitaxial effect can arise from two considerations, namely the crystalline orientation and surface roughness of the seeding layer, which can be controlled by the curing temperature. The ZnO seeding layer that was cured at 350°C exhibited a preferred (0002) crystalline orientation of wurtzite hexagonal structure and a low surface roughness. It was demonstrated to promote the vertical growth of ZnO nanorods. The ZnO nanorods grew in an almost linear relationship with hydrothermal time up to 8 h, but thereafter started to dissolve as the reaction time extended beyond 8 h, due to competition from the homogeneous nucleation of ZnO microparticles in the solution.
Aligned carbon nanotube films for cold cathode applications

Thin film material of oriented multiwall carbon nanotubes was obtained by noncatalytical chemical vapor deposition in a glow-discharge plasma. The film phase composition, surface morphology, and structural features were studied by Raman and electron microscopy techniques. Low-voltage electron field emission of thin film nanotube material was obtained and examined in diode configuration. The I–V curves in Fowler–Nordheim coordinates were linear and the corresponding threshold average field was about 1.5 V/μm. The emission current density was up to 50 mA/cm2 at the field of 5 V/μm. The emission site density reached 107 cm−2 at the same value of electric field.