Miracle-dz/UniFAR-FTUs huggingface dataset:
Dissolved Organic Carbon

The importance of dissolved organic carbon (DOC) lies in its role in the biogeochemical carbon cycle, as a necessary basis for aquatic microbial processes and in aquatic chemistry. Although the global burden of carbon is dominated by sediments, dissolved organic carbon is of obvious importance as carbon is the basis of life, an energy and nutrient source for microorganisms. DOC is also of significance in trace pollutant binding (and consequently in pollutant transport and bioavailability), in the charge and aggregation behavior of colloids, in weathering, in pH buffering, and in acid–base and redox chemistry of natural waters. It thus has a large and essential role in determining the chemical composition of natural waters. Although microbiological and chemical aspects are frequently taught and researched in isolation, it may be impossible to understand the composition and regulation of natural waters without simultaneously considering the microbiological and chemical processes because they are so closely interlinked. Any distinction between the two processes is therefore likely to be arbitrary and misleading. Keywords: dissolved organic carbon; colloidal organic carbon; particulate organic carbon; organic carbon; humic substances; microbes; (microbiological cells); aquatic chemistry; filtration; polysaccharides; carbon cycle
Crystal Size, Morphology, and Growth Mechanism in Bio‐Inspired Apatite Nanocrystals

Bio‐inspired apatite nanoparticles precipitated in the presence of citrate ions at increasing maturation times are characterized in terms of structure, size, morphology, and composition through advanced X‐ray total scattering techniques. The origin of the platy crystal morphology, breaking the hexagonal symmetry, and the role of citrate ions is explored. By cross‐coupling the size and shape information of crystal domains with those obtained by atomic force microscopy on multidomain nanoparticles, a plausible mechanism underlying the amorphous‐to‐crystal transformation is reconstructed. In the present study, citrate plays the distinct roles of inducing the platy morphology of the amorphous precursor and controlling the thickness of the Ca‐deficient apatite nanocrystals. These findings can open new scenarios also in bone mineralization, where citrate might have a broader role to play than has been thought to date.
Norfloxacin Sorption to Different Fractions in Sediments from Typical Water Systems in China

Sorption isotherms of Norfloxacin (NOF) to different fractions from six typical sediments in China were determined to compare the NOF sorption behavior and contribution of different fractions to total sorption. All sorption isotherms were nonlinear and fitted well with the Freundlich model. Sorption coefficients (K f) by original sediments changed in larger magnitude, from 114 (mg/g)/(mg/L)n to 5271 (mg/g)/(mg/L)n, and black carbon with more aromatic carbon has more sorption capacity and nonlinearity. The sorption capacity K f values were found to significantly correlate with SSA (specific surface area), OC (organic carbon), BC (black carbon), and TON (total organic nitrogen) (p < 0.05), but had no obvious relation with pH, CEC (cation exchange capacity), TOC/TON, and BC/TOC. The DOC removed, NaOH extracted, and 375°C heated fractions showed more nonlinear sorption than the original sediments, suggesting more heterogeneous sorption sites in these fractions. Among different sediment fractions, the 375°C heating fractions were responsible for >50% of the total NOF sorption over the whole concentration range. The contribution of DOC removed fractions to the total sorption was the highest at higher NOF concentration.
Cu2S/Au core/sheath nanowires prepared by a simple redox deposition method

We have deposited continuous Au films on the Cu2S nanowire surfaces using a simple redox reaction, forming a novel type of Cu2S/Au core/sheath nanowires. The core/sheath nanostructures were characterized by various spectroscopic and microscopic techniques. The Cu2S core that was used as the template was typically ∼60 nm thick, and the Au coating was from a few nm up to 100 nm thick depending on the coating time period and the concentration of Au3+ in the coating solution. The Au coating layer was found to be polycrystalline. For relatively thick Au coatings, we have successfully fabricated Au nanotubes by etching away the Cu2S core.
Mesoporous Anatase Titania Hollow Nanostructures though Silica‐Protected Calcination

The crystallization of nanometer‐scale materials during high‐temperature calcination can be controlled by a thin layer of surface coating. Here, a novel silica‐protected calcination process for preparing mesoporous hollow TiO2 nanostructures with a high surface area and a controllable crystallinity is presented. This method involves the preparation of uniform silica colloidal templates, sequential deposition of TiO2 and then SiO2 layers through sol–gel processes, calcination to transform amorphous TiO2 to crystalline anatase, and finally etching of the inner and outer silica to produce mesoporous anatase TiO2 shells. The silica‐protected calcination step allows crystallization of the amorphous TiO2 layer into anatase nanocrystals, while simultaneously limiting the growth of anatase grains to within several nanometers, eventually producing mesoporous anatase shells with a high surface area (∼311 m2 g−1) and good water dispersibility upon chemical etching of the silica. When used as photocatalysts for the degradation of Rhodamine B under UV irradiation, the as‐synthesized mesoporous anatase shells show significantly enhanced photocatalytic activity with greater enhancement for samples calcined at higher temperatures thanks to their improved crystallinity.
Organic Field-Effect Transistors Based on Oligo-p-Phenylenevinylene Derivatives

Organic field-effect transistors (OFETs) have been fabricated using thermally vacuum-evaporated films of two oligo-p-phenylenevinylenes, 1,4-bis(4-methylstyryl)benzene (4MSB), and 1,4-bis(2-methylstyryl)benzene (2MSB). From the electrical characteristics of the OFETs, a field-effect mobility of the 4MSB films was calculated to be 0.13 cm2 V-1 s-1, while the mobility of the 2MSB films was 1.0 ×10-4 cm2 V-1 s-1. The mobility of 4MSB is comparable to that of widely studied organic semiconductors, such as oligothiophenes and pentacene. From atomic force microscopy and X-ray diffraction, densely-packed submicron-size grains with a high degree of molecular order were observed in a vacuum-sublimed 4MSB film.
Effect of modified carbon black on the UV/IR screening ability of poly(ethylene terephthalate) transparent films

The mixed solution of poly (ethylene terephthalate) (PET)/carbon black (CB) and PET/modified CB (m-CB) were coated on glass substrates to fabricate light screening films. m-CB was prepared using a solid phase modification method through mechanical blending of CB and 2-(2′-Hydroxy-5′-methylphenyl)-benzotriazole (UV-P) in weight composition of 50 : 50. The results of dynamic light scattering (DLS), optical microscopy, and scanning electron microscopy (SEM) showed that the modification of CB obviously reduced the particle and aggregate sizes of CB, leading to better dispersion of m-CB in PET films. Fourier transform infrared spectroscopy (FTIR) proved that UV-P was grafted on CB after blending and changed the molecular structure of CB. Ultraviolet-visible-Infrared (UV-vis-IR) spectrophotometer tests showed that the UV/IR absorption property of the films improved obviously while the visible light transmittance reduced gradually with the increase of m-CB content from 0.5 to 6 wt%. Differential scanning calorimeter (DSC) results showed the addition of 4 wt% m-CB decreased the crystallinity of PET matrix, which effectively inhibited the destruction of the film transparency with the addition of more CB. POLYM. COMPOS. , 2011. © 2010 Society of Plastics Engineers
Enhanced passivation at amorphous/crystalline silicon interface and suppressed Schottky barrier by deposition of microcrystalline silicon emitter layer in silicon heterojunction solar cells

In silicon heterojunction (SHJ) solar cells, the embedded p-layer (emitter) between transparent conductive oxide (TCO) and crystalline silicon is depleted form both sides. Hence, high level of doping is required to preserve flat band. In this report, the role of the emitter conductivity on the electrical properties of SHJ solar cells is investigated. We offer depositing microcrystalline silicon (μc-Si) films to satisfy the required emitter conductivity and to suppress the Schottky barrier when employing low work function TCO material. Finally, by depositing μc-Si layers, the passivation of solar cell precursors improves and current increases, due to their low absorption coefficient.
Bacteria diversity and microbial biomass in forest, pasture and fallow soils in the southwestern Amazon basin

Os solos da floresta tropical amazonica supostamente abrigam elevada biodiversidade microbiana. Entretanto, as acoes antropicas de corte e queima, especialmente para o estabelecimento de pastagens, induzem mudancas profundas nos ciclos biogeoquimicos. Apos alguns anos de uso, a produtividade da graminea declina, a pastagem e abandonada, tornando-se uma vegetacao secundaria, denominada "capoeira" ou pousio. O objetivo deste trabalho foi avaliar como o desmatamento da floresta amazonica para o estabelecimento de pastagem altera: a diversidade do dominio Bacteria avaliada por PCR-DGGE; a biomassa microbiana e alguns atributos quimicos do solo (pH, umidade, P, K, Ca, Mg, Al, H + Al e SB); e a influencia de variaveis ambientais na estrutura genetica de comunidades bacterianas. A pastagem continha entre 30 e 42 % mais carbono total (C) do que a capoeira e aproximadamente 47 % mais C do que a floresta ao longo do ano. O mesmo padrao foi observado para o nitrogenio total (N). A biomassa microbiana na pastagem foi 38 e 26 % maior do que nas areas de capoeira e floresta, respectivamente, durante a estacao chuvosa. O padrao de bandas em DGGE revelou menor numero de bandas por area na estacao seca, porem as diferencas na estrutura de comunidades bacterianas entre as areas de estudo foram mais bem definidas do que na estacao chuvosa. O perfil de bandas encontrado na floresta esteve mais associado ao teor de Al e as taxas Cmic:Ctot e Nmic:Ntot. Em relacao as areas de pastagem e capoeira, a estrutura do dominio Bacteria esteve mais associada a pH, soma de bases, umidade, C e N totais e a biomassa microbiana. De modo geral, a biomassa microbiana em solos e influenciada pelos teores de C e N totais, os quais estiveram associados ao dominio Bacteria, visto que a comunidade bacteriana e uma fracao componente e ativa da biomassa microbiana. Os resultados indicam que a composicao genetica das comunidades microbianas dos solos da Amazonia mudou ao longo da sequencia floresta-pastagem-capoeira.
A Biophysical Study of Clathrin Utilizing Light Scattering, Neutron Scattering and Structure Based Computer Modeling

Title of dissertation: A BIOPHYSICAL STUDY OF CLATHRIN UTILIZING LIGHT SCATTERING, NEUTRON SCATTERING AND STRUCTURE BASED COMPUTER MODELING Matthew Lee Ferguson, Doctor of Philosophy, 2007 Dissertation directed by: Dr. Ralph Nossal National Institute of Child Health and Human Development and Professor Wolfgang Losert Department of Physics A principal component in the protein coats of certain post-golgi and endocytic vesicles is clathrin, which appears as a three-legged heteropolymer (known as a triskelion) that assembles into polyhedral baskets principally made up of pentagonal and hexagonal faces. In vitro, this assembly depends on the pH, with baskets forming more readily at low pH and less readily at high pH. We have developed procedures, based on static and dynamic light scattering, to determine the radius of gyration, Rg, and hydrodynamic radius, RH , of isolated triskelia under conditions where basket assembly occurs. Calculations based on rigid molecular bead models of a triskelion show that the measured values can be accounted for by bending of the legs and a puckering at the vertex. We also show that the values of Rg and RH measured for clathrin triskelia in solution are qualitatively consistent with the conformation of an individual triskelion that is part of a ”D6 barrel” basket assembly measured by cryo-EM tomography. We extended this study by performing small angle neutron scattering (SANS) experiments on isolated triskelia in solution under conditions where baskets do not assemble. SANS experiments were consistent with previous static light scattering experiments but showed a shoulder in the scattering function at intermediate q-values just beyond the central diffraction peak (the Guinier regime). Theoretical calculations based on rigid bead models of a triskelion showed well-defined features in this region different from the experiment. A flexible bead-spring model of a triskelion and Brownian dynamics simulations were used to generate a time averaged scattering function. This model adequately described the experimental data for flexibilities close to previous estimates from the analysis of electron micrographs. A BIOPHYSICAL STUDY OF CLATHRIN UTILIZING LIGHT SCATTERING, NEUTRON SCATTERING AND STRUCTURE BASED COMPUTER MODELING by Matthew Lee Ferguson Dissertation submitted to the Faculty of the Graduate School of the University of Maryland, College Park in partial fulfillment of the requirements for the degree of Doctor of Philosophy 2007 Advisory Committee: Dr. Ralph J. Nossal, Co-Chair/Advisor Professor Wolfgang Losert, Co-Chair/Advisor Dr. Dan L. Sackett Professor Sandra Greer Professor J. Robert Dorfman Professor Robert W. Gammon c © Copyright by Matthew Lee Ferguson 2007
Angle resolved photoelectron spectroscopy of the valence shells in HI and CH3I as a function of photon energy from 13 to 90 eV

Angle‐resolved photoelectron spectroscopy was carried out on the valence shells of HI and CH3I over a photon energy range of 13–90 eV with the use of synchrotron radiation. From these data, partial cross sections and angular distribution parameters were obtained for bands corresponding to the 1 2Π and 1 2Σ+ states of singly ionized HI and the 1 2E, 1 2A and 2 2E states of singly ionized CH3I. Calculations were carried out on HI for the same parameters with the use of the multiple scattering Xα method. The results, both experimental and theoretical, are examined in terms of the Cooper minimum. Clear evidence for minima in both the cross sections and β values are found for the lone‐pair orbitals. Bonding orbitals involving the iodine 5p subshell also show minima in the energy dependence plot of the β values, but the effects are less pronounced. These results are compared with similar studies on chlorine‐containing molecules. The lone‐pair orbitals showed spin‐orbit resolved bands in the photoelectron spectr.
Scientific issues and potential remote-sensing requirements for plant biochemical content

Application of developments in imaging spectrometry to the study of terrestrial ecosystems, which began in 1983, demonstrate the potential to estimate lignin and nitrogen concentrations of plant canopies by remote-sensing techniques. Estimation of these parameters from the first principles of radiative transfer and the interactions of light with plant materials is not presently possible, principally because of lack of knowledge about internal leaf scattering and specific absorption involving biochemical compounds. From the perspective of remote-sensing instrumentation, sensors are needed to support derivative imaging spectroscopy. Biochemical absorption features tend to occur in functional groupings throughout the 1100- to 2500-nm region. Derivative spectroscopy improves the information associated with the weaker, narrower absorption features of biochemical absorption that are superimposed on the strong absolute variations due to foliar biomass, pigments, and leaf water content of plant canopies. Preliminary sensor specifications call for 8-nm bandwidths at 2-nm centers in four spectral regions (about 400 bands total) and a signal-to-noise performance of at least 1000:1 for 20 percent albedo targets in the 2000-nm region.
Physical activation of biochar and its meaning for soil fertility and nutrient leaching – a greenhouse experiment

The slow alteration of the surface of charred biomass (biochar) over time may contribute to an improved nutrient retention and thus fertility of tropical soils. Here, we investigated soils from temperate climates and investigated whether a technical steam activation of biochar could accelerate its positive effects on nutrient retention and uptake by plants relative to nonactivated biochar. To this aim, we performed microcosm experiments with sandy or silty soil, mixed with 2.0, 7.5 and 15.0 g/kg soil of fine (<2 mm) or coarse‐sized (2–10 mm) biochar from beech wood (Fagus sp.). After initial fertilizer (NPK), ashes and excess nutrients were leached with water, and the microcosms were planted for 142 days with Italian Ryegrass (Lolium multiflorum ssp. italicum). Thereafter, leachate, soil and plant samples were analysed for their nutrient contents. The results showed that biochar additions of ≤15 g/kg soil left elevated contents of available P and N in the surface soil but reduced their uptake into the plants. As a result, total biomass production was unchanged. Different particle size and application amounts influenced these findings only marginally. Nitrate leaching was enhanced in the sandy soil (+41% for nitrate, but reduced in the silty soil −17%) and P was immobilized. Hence, the fertility of the temperate soils under study was only marginally affected by pure biochar amendments. Steam activation, however, almost doubled the positive effects of biochars in all instances, thus being an interesting option for future biochar applications.
Single Nanoparticle Ion Trap (SNIT): A Novel Tool for Studying in-situ Dynamics of Single Nanoparticles

The development of high performance single nanoparticle ion trap (SNIT) apparatus for studying in-situ dynamics of single nanoparticles in controlled environments is described. The performance of SNIT apparatus has been evaluated for 500 nm SiO 2 particles. The mass resolution of ∼100 ppm and the capability of varying the charge states independently have been demonstrated.
Alignment of rod-shaped gold particles by electric fields

The electro-optical response of colloidal dispersions of rod-shaped gold particles is studied for various aspect ratios (2.6 < L/d < 49; d = 15 nm) by monitoring the absorbance spectra in the visible wavelength regime. The absorbance spectra strongly depend on the degree of orientational order of the rods and the direction of the polarization of the incident light with respect to the applied electric field. From the change in absorbance of the transverse resonance the electro-optical effect is deduced: at low electric field strengths a linear dependence on the squared electric field strength is observed, and at sufficiently high electric field strengths saturation occurs. This is in agreement with electro-optical theory. With increasing length, the anisotropy in electric polarizability increases from 6.10-30 F.m2 to 12.10-30 F.2. It is found that the anisotropy in electric polarizability depends on the square root of the particle length.
Seed-Mediated Synthesis of Pd Nanocrystals: Factors Influencing a Kinetic- or Thermodynamic-Controlled Growth Regime

Palladium nanoparticles with defined morphologies were synthesized using a seed-mediated approach in the presence of cetyltrimethylammonium bromide (CTAB). This seeding technique, already applied to Ag and Au nanostructures, was successfully extended here to Pd, a noble metal with important applications in catalysis. Various types of morphologies were obtained going from 0-D nanocrystals (cubes, icosahedral multiply twinned particles) to 1-D (nanorods) and 2-D nanocrystals (triangular nanosheets). Palladium nanorods were obtained in a relatively high yield and present a well-defined 5-fold symmetry similar to that reported previously for Ag and Au. Embedding the PdCl42- precursor inside CTAB micelles was found to be a key parameter to decrease the rate of reduction of palladium and to allow a better kinetic-controlled growth regime, favoring the formation of nanorods. Shifting the experimental conditions to a thermodynamic-controlled growth regime also selectively led to the formation of cubic (∼80%) or i.
Thermal Properties of Cyano-Based Ionic Liquids

Nowadays, extraction of aromatics from aromatic/aliphatic mixtures is being investigated using cyano-based ionic liquids (ILs) as a new green alternative to currently used conventional organic extraction solvents, such as sulfolane. In this process, the maximum operation temperature (MOT) of the IL is a decisive property to know. Thus, thermal behavior of ILs is a target issue to study. The MOTs of cyano-based ILs 1-ethyl-3-methylimidazolium dicyanamide ([emim][DCA]), 1-butyl-3-methylimidazolium dicyanamide ([bmim][DCA]), 1-ethyl-3-methylimidazolium thiocyanate ([emim][SCN]), 1-butyl-3-methylimidazolium thiocyanate ([bmim][SCN]), and 1-ethyl-3-methylimidazolium tricyanomethanide ([emim][TCM]) have been determined using dynamic and isothermal thermogravimetric analyses. In addition, specific heats from (296.2 to 372.2) K of all ILs included in this work have been also measured using differential scanning calorimetry (DSC). The MOT for [emim][TCM] was the highest, whereas the MOT for [emim][DCA], [bmim][DCA.
Induced Ferromagnetic Interactions in Langmuir−Blodgett Films of an Organic Radical

The elaboration of a purely organic ferromagnet requires a precise supramolecular organization, but up to now, it has proven impossible to control or even predict the way a given molecule will crystallize. We present here results showing that the Langmuir−Blodgett technique allows for such a control. Starting from a material with antiferromagnetic intermolecular interactions, we have been able to build monolayer Langmuir−Blodgett films with ferromagnetic interactions, as evidenced by electron spin resonance measurements.
Electrophoretic transport of spheroidal colloids in nonhomogeneous electric fields

The velocity of a uniformly charged spheroid in a spatially varying electric field, E∞(x), is determined. The electrical double layer at the particle's surface is assumed to be very thin relative to the size of the particle. The electric field produces a slip velocity at the surface of the particle that drives the electrophoretic motion. If the particle is not a sphere, then its velocity is not given simply by Smoluchowski's equation. The translational velocity of the particle is proportional to E∞ and ⊇⊇E∞, while the angular velocity is proportional to ⊇E∞. Examples are presented to demonstrate the effectiveness of nonhomogeneous fields in orienting particles with and without the opposing effects of Brownian rotation. It should be possible to design electrode configurations that would produce the nonhomogeneous electric fields necessary to align and transport colloidal particles in a desired manner.