Miracle-dz/UniFAR-FTUs huggingface dataset:
Nuclear Transfer Effects in Nuclear Magnetic Resonance Pulse Experiments

The Bloch equations for the nuclear magnetic resonance of a single nuclear species which is transferred between state environments having different relaxation times (T1 or T2) and different resonance frequencies have been solved for rf pulse experiments. Expressions have been obtained for the free precession signals in two‐pulse experiments. A theoretical study of the signal envelopes has been made for several specific instances. In particular, the effect of the frequency difference between the two states on transverse (T2) relaxation has been investigated; the predicted effect is large in some cases. The longitudinal (T1) relaxation is independent of the frequency separation. A reduction of phase dispersion by the second pulse which is similar to that in molecular diffusion is also predicted.
Soil humic acid aggregation by dynamic light scattering and laser Doppler electrophoresis

Humic acids (HAs), similar to other fractions of humic substances (HSs), have a large number of reactive functional groups enabling them to aggregate in solutions. Regardless of the origin of humic acid (aqueous or soil), this aggregation process is dependent on environmental conditions and strongly influences the mobility of soluble ionic and molecular pollutants. The aim of this work was to monitor the aggregation process of two humic acids isolated from different mineral soils (IHSS Elliot soil HA standard and Rendzic Leptosol HA) in the 2–11 pH range. Changes in aggregate size in HA sols were followed up using dynamic light scattering (DLS), while zeta potential (ZP) measurements in the same pH range were performed applying laser Doppler electrophoresis (LDE) technique. The effect of HA sol concentration and soil source on aggregation was examined as well. Besides, HA samples were characterized using Fourier transform infrared (FT-IR) spectroscopy. By inspecting HA-particle-size dependence on pH, it can be concluded that both HAs in corresponding sols behave as molecular aggregates or supramolecular structures, formed from small individual moieties (sizes < 10 nm) at higher pH values. The ZP vs. pH curve for both HAs revealed the ZP minimum in the 5–7 pH range, caused most likely by dissociation of acidic functional groups prevailing at lower pH values and deaggregation predominating over dissociation at higher pH values.
Effects of Polyene Chain Length and Acceptor Substituents on the Stability of Carotenoid Radical Cations

The stability of radical cations of three series of carotenoids substituted with terminal ester, aldehyde, and cyano groups and with different numbers of backbone double bonds was studied by electrochemical and optical methods. The ethyl esters are 8‘-apo-β-caroten-8‘-oate (I), 6‘-apo-β-caroten-6‘-oate (II), and 4‘-apo-β-caroten-4‘-oate (III); the aldehydes are 8‘-apo-β-caroten-8‘-al (IV), 6‘-apo-β-caroten-6‘-al (V), and 4‘-apo-β-caroten-4‘-al (VI); and the cyano compounds are 8‘-apo-β-caroten-8‘-nitrile (VII), 6‘-apo-β-caroten-6‘-nitrile (VIII), and 4‘-apo-β-caroten-4‘-nitrile (IX). Cyclic voltammetry (CV) and Osteryoung square wave voltammetry (OSWV) results indicate that the stability of carotenoid radical cations depends on the number of conjugated chain double bonds. For the esters, the longer the olefin chain, the more unstable the radical cations. In contrast, for the aldehydes and the nitriles, the stability of the radical cations is similar or varies slightly with backbone chain length. The half-.
The Generation and Characterization of Metallic and Mixed Element Aerosols for Human Challenge Studies

A spark discharge aerosol generator (Palas GFG 1000) has been utilized to generate aerosols of pure metals and of carbonaceous aerosols containing a metal component. This was achieved by fabricating metal electrodes of the desired dimensions and also by repeated instillation of saturated FeCl 2 solution into a machined recess in an existing graphite electrode. Number size distributions of the resultant aerosols were measured, and field emission gun transmission electron microscopy (FEG TEM), coupled with energy dispersive X-ray (EDX) analysis, were performed on the collected samples. Whilst utilizing two identical metallic electrodes, it was found that particle-number concentration and modal diameter generally increased with a greater electrical and thermal resistivity of the electrode material. Utilizing zinc as a single electrode, or pair of electrodes, one observed an effect of enhanced airborn mass concentration of this element upon spark discharge. It is postulated that this phenomenon was due to zinc's inherent low melting and boiling points. Measurements performed with EDX analysis indicated the composition of carbon/metal aerosols to consist primarily of carbon. Aerosols generated using a stainless steel/carbon system show dense regions present, with an observed composition very close to that of stainless steel, indicating little, if any, fractionation of these particular elements during the aerosol formation process. This observation, together with evidence gained from FEG TEM imaging in further systems, suggests that droplet formation directly from the metallic electrode surface constituted an important role in the aerosol formation process.
Influence of soil properties on sorption‐desorption of imidacloprid

Abstract Sorption‐desorption studies of imidacloprid (1‐[(6‐chloro‐3‐pyridmyl)methyl]‐N‐mtro‐2‐imidazolidinimine) were conducted using the batch equilibration method with seven U.S. soils varying in their physicochemical properties. Initial imidacloprid concentrations ranged from 3 to 300 μg L‐1. Sorption coefficients Kf and the soil properties organic carbon and CEC gave the higher single correlation coefficients; the latter due to the positive correlation between OC and CEC. Sorption was irreversible and desorption hysteresis in general was greater at low soil solution concentrations. Kf values were lower at 1:5 soil:solution ratio than at 1:1, suggesting a possible effect of a soluble soil component, such as salt concentration, on sorption; no significant differences in pH between solutions were detected.
A preliminary study of green production of fiberboard bonded with tannin and laccase in a wet process

Abstract A gluing method for fiberboard based on laccase-activated tannin and wood fibers was investigated on a laboratory scale. Oxygen consumption measurements showed that hydrolyzable tannins (tannic acid and chestnut tannin) were more reactive toward laccase than condensed tannins from mimosa and quebracho. Wet-process hardboard prepared with laccase and the most reactive tannin, tannic acid, had superior mechanical strength compared to controls and boards made with laccase alone or laccase and other tannins. The other tannins did not improve mechanical properties more than laccase treatment alone. The addition of wax to the tannic acid-laccase formulation improved the dimensional stability of the boards enough for them to comply with industrial standards, although wax had a negative impact on the mechanical properties. The results cannot be directly applied to dry-process medium-density fiberboard (MDF) production; however, the positive effects of tannin and laccase on hardboard properties also warrant investigations on the green chemistry of MDF production.
A Novel Method for Dye Removal: Ionic Liquid-Based Dispersive Liquid–Liquid Extraction (IL-DLLE)

A novel, simple, fast, and efficient ionic liquid-based dispersive liquid–liquid extraction (IL-DLLE) has been applied to extract and remove Congo Red (CR; a carcinogenic textile dye) from aqueous solutions. In this methodology a binary solution, containing the extraction solvent (1-hexyl-3-methylimmidazolium bis(trifluormethylsulfonyl) imid) and a suitable disperser solvent, was rapidly injected into the water sample containing CR dye. Therewith, a cloudy solution was formed, and most of the dye molecules were extracted into fine IL droplets and removed from aqueous phase. The effects of pH, type, and amount of IL, initial concentration of the dye, type and volume of the dispersant, and concentrations of salt on the extraction of the dye were studied. Experimental surveys were also accomplished for recovery of the IL by applying a reverse dispersive liquid–liquid extraction using acidic stripping solutions.
Analysis, Design, and Modeling of Image-Guided Robotic Systems for Otologic Surgery

Otology and neurotology are surgical specialties focusing on the treatment of ear diseases. A key component of many otologic and neurotologic surgical procedures is the removal of a portion of the skull behind the ear to gain access to subsurface anatomy. This process, called a mastoidectomy, is performed manually with a high speed surgical drill. Many vital structures, including nerves and blood vessels, are embedded within the temporal bone near the region of bone that must be removed, which makes the procedure difficult, time consuming, and in some cases, overly invasive. Image-guided and robotic systems have the potential to improve otologic procedures using medical imaging to guide their interventions, enabling patient-specific treatments that reduce invasiveness and save valuable operating room time. However, since damage to the complex vital structures within the surgical field could result in severe consequences to the patient, any image-guided or robotic surgical system must be extremely safe and accurate. These requirements, along with the small surgical workspace and difficulty integrating systems into the current clinical workflow, have limited the adoption of such systems in otologic surgery to date. This dissertation presents the design, experimentation, and analyses of imageguided, robotic systems under development for otologic surgery in an effort to bring these systems closer to clinical realization. The specific goals of the work are to better understand the technical requirements of various otologic surgical procedures, to improve the safety and efficiency of image-guided and robotic surgery by incorporating system modeling and medical image data into the surgical planning process, and to
Chemical Bonding Character and Physicochemical Properties of Mesoporous Zinc Oxide-Layered Titanate Nanocomposites

We have investigated the chemical bonding character and physicochemical properties of mesoporous zinc oxide-layered titanate nanocomposites synthesized by an exfoliation−restacking route. According to our analyses using X-ray diffraction, high resolution transmission electron microscopy, and N2 adsorption−desorption isotherm measurements, nanocrystalline zinc oxides are stabilized not only in the interlayer space of the host titanate but also in the mesopores of the nanocomposites formed by the house-of-card type stacking of the crystallites. X-ray absorption spectroscopic analyses at Ti K- and Zn K-edges clearly demonstrate that nanocrystalline zinc oxides crystallized with a Wurzite type structure, and the lepidocrocite structure of the host titanate remains unchanged after hybridization and postcalcination. Upon hybridization with zinc oxide nanoparticles, the photocatalytic activity of layered titanate is enhanced with respect to the oxidative photodegradation of phenol and dichloroacetate. But of gre.
The Impact of Introducing the New Corporate Governance Code on the level of Voluntary Risk Disclosure with an Empirical Study on the Egyptian listed Companies

: This study aimed to examine the changes in the level of corporate risk disclosures before and after introducing new corporate governance code 2016 and empirically explore the key factors that may affect the extent of voluntary risk information disclosed. The sample of the study consists of 55 companies for years 2014, 2015, 2016 and 2017 . The study used content analysis to identify voluntary risk disclosure. The statistical techniques used to test the hypotheses are parametric techniques that are multiple regression and paired sample t-test. The findings revealed that the level of voluntary risk disclosure has been improved after issuing new corporate governance rules. The study also found there is a positive significant relationship between role duality, audit committee effectiveness, auditor type and voluntary risk disclosure. On the other hand, there is no significant relationship between board size, board composition, board activity and voluntary risk disclosure.
Experimental setup for in situ X-ray SAXS/WAXS/ PDF studies of the formation and growth of nanoparticles in near- and supercritical fluids

The growing interest in inorganic nanoparticles for a wide range of applications is spurring a need for synthesis methods that allow a highly specific tailoring of material properties. Synthesis in supercritical fluids holds great promise for solving this problem, but so far the fundamental chemical processes taking place under these conditions are to a large extent unknown. Here the design, construction and application of a versatile experimental setup are reported; this setup enables in situ synchrotron small-angle X-ray scattering/wide-angle X-ray scattering/pair distribution function (SAXS/WAXS/PDF) studies of the formation and growth of nanoparticles under supercritical fluid conditions.
Hydration of sodium phosphate-modified high alumina cement

High strength can be achieved in high alumina cement (HAC) through the incorporation of phosphate-based additions at levels of 10 and 20 wt. %. In order to establish the mechanism that results in higher strength, the effects of a variety of condensed sodium phosphates (NaPO_3)_ n , (NaPO_3)_ n · Na_2O, Na_5P_3O_10, and (NaPO_3)_3 were studied. The influence of these additions on the kinetics of hydration was studied using isothermal calorimetry. The phosphatic additions enhanced reactivity, but x-ray diffraction analyses did not reveal evidence of new crystalline phosphate-containing hydration products. Microstructural evolution was examined in real time using environmental SEM, and hydration products exhibiting distinct morphologies were observed. The features exhibited ranged from amorphic to polygonal shapes, plates, and fibers. These frequently formed between crystalline calcium aluminate hydrate grains and by doing so appear to provide a means to enhance the strengths of these cements. In spite of the morphological variations, companion energy dispersive x-ray analysis showed that the compositions of these products did not vary widely. Their ranges of compositions are 52-60 wt. % Al_2O_3, 20-26 wt. % P_2O_5, and 20-24 wt. % CaO.
Inhibiting diatom motility: a new tool for the study of the photophysiology of intertidal microphytobenthic biofilms

The study of the photophysiology of intertidal microphytobenthos biofilms has been hampered by the confounding effects of vertical migration by motile microalgae. The present work introduces a methodology to obtain undisturbed nonmigratory biofilms, based on the diatom motility inhibitor latrunculin A (Lat A). Application of Lat A to intact sediments prevented light‐induced vertical migration while not affecting the biofilm photosynthetic activity or disrupting the photic zone microenvironment. The inhibition of microalgal migration maintained the surface microalgae biomass despite exposure to stimuli that induced large migratory responses in noninhibited samples, including supersaturating irradiances or darkness. The characterization of the photophysiological responses of undisturbed biofilms without the interference of changes in surface biomass was illustrated by addressing two questions that are not possible to study on migratory biofilms with the existing methods: (i) the construction of light‐response curves of steady‐state photosynthetic activity, commonly used to characterize the photoacclimation status of photoautotrophs, and (ii) the characterization of the induction and relaxation kinetics of nonphotochemical quenching of in vivo fluorescence, required for the study of photoprotective processes or photoinhibition.
Kinetic Stability of Lutein in Freeze-Dried Sweet Corn Powder Stored under Different Conditions

The powder of freeze-dried sweet corn was stored under different conditions at 4, 20 and 37°C for 12 weeks, and the stability of lutein and its isomers during storage were studied. It was found that total lutein content declined depending on storage conditions and the kind of lutein isomer. The highest residual of all-trans-lutein was found stored at 4°C with vacuum and dark. Under the storage of air and light at 37°C, major isomers 9-cis-lutein, 9’-cislutein, 13’-cis-lutein and 13-cis-lutein showed significant increases by 35.0, 50.0, 38.4 and 37.1%, respectively, of its original content after 12 weeks of storage, which indicated isomerization might take place during storage. The kinetics of all-trans-lutein degradation under different conditions followed first order kinetics well, the apparent rate constant values were lowest under vacuum and dark and highest under air and light at each storage temperature, confirming potential detrimental effects of oxygen and light on lutein loss.
Phase Structure and Properties of Toughened Poly(L-Lactic Acid)/Glycidyl Methacrylate Grafted Poly(Ethylene Octane) Blends Adjusted by the Stereocomplex

A detailed study of reactively toughened poly(L-lactic acid) (PLLA)/glycidyl methacrylate grafted poly(ethylene octane) blends is reported, and stereocomplex (SC) formed from PDLA incorporated was used to adjust the phase morphology. It was found that blends with 20 wt% of POE-GMA exhibited highest impact strength and incorporation of PDLA with 1 wt% had further improved the impact toughness and tensile strength. SEM revealed that SC had induced the crushing of the dispersed phase-size of the blends. The simultaneous enhancement of impact and tensile strength induced by SC would provide a new strategy to accelerate the commercial use of toughened PLLA blends.
Influence of sample pretreatment on the extractability of polycyclic aromatic hydrocarbons (PAH) from forest floor horizons

Extraction of PAH from Oh-horizon material after dispersion of air-dried samples in water resulted in a 80% higher yield of 20 PAH species compared to extraction of air-dried, freeze-dried or ground samples. Concurrently, the free surface area (BET method) of the organic matter increased. It was assumed that dispersion resulted in a disaggregation and/or stretching of organic aggregates, which makes interior aggregate regions available to the extractant that were pre-viously not accessible for the extractant due to diffusion barriers. Einflus der Probenvorbehandlung auf die Extrahierbarkeit polyzyklischer aromatischer Kohlenwasserstoffe (PAK) aus organischen Auflagehorizonten Die Extraktionsausbeute von 20 PAK aus einem Oh-Horizont unter Fichte lag fur in Wasser dispergierte Proben um 80% hoher als fur Proben, welche luftgetrocknet, gefriergetrocknet bzw. gemahlen wurden. Dies ging mit einem gleichlaufenden Anstieg der freien Ober-flache (BET-Methode) der organischen Substanz einher. Diese Beobachtung durfte auf Disaggregierung bzw. auf eine Streckung organischer Aggregate durch die Dispergierung zuruckzufuhren sein; deren Inneres entzog sich vorher aufgrund von Diffusionsbarrieren einer Extraktion.
Use of spherical and spheroidal models to calculate zooplankton biovolume from particle equivalent spherical diameter as measured by an optical plankton counter

Three methods of calculating the biovolume of particles from their shadows as recorded by and optical plankton counter (OPC), based on optical geometry, are presented. In the first method (Vsphere), particles are assumed to be opaque spheres. In the other two methods, particles are represented as opaque spheroids, oriented with their major axes either parallel to the flow thus presenting maximum shadow area (Vmax), or randomly orientated relative to the flow (Vran). The models were tested by comparing with net biovolume, measured from samples of a zooplankton assemblage dominated by Calanus finmarchicus collected during a cruise to the northeast Atlantic during 2001. The randomly orientated spheroidal model (Vran) provided the best fit with the net data: on average the ratio of OPC biovolume to net biovolume was 1.02, compared to ratios of 0.84 when calculating OPC biovolume as Vmax and 1.50 when calculating as Vsphere. The Vran and Vmax methods gave reasonable estimates of net biovolume from OPC measurements without recourse to the use of empirical tuning parameters that are otherwise required. This success was enhanced by the fact that the community chosen for validation purposes was dominated by a single species, C. finmarchicus, which could be approximated by spheroids of known dimension. The calibration methods are less likely to be effective when applied to zooplankton communities incorporating a diverse range of organisms.
Studies on the nicotinic acetylcholine receptor of the locust

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Distribuição espacial de pivôs centrais no Brasil: I - região sudeste

Irrigated areas by state and by irrigation method is the available information about irrigation in Brazil. Distribution inside the states, number or size is not easily found even through the industry. These data are very important when one intends to study water availability or growth potencial of irrigated areas for a specific site due to the increasing concern about drinking water worldwide and nationally. The present study had the objective to collect such information using satellite images from Landsat based on the intrinsic characteristic of the center pivot equipments, the circular mark on landscape easily visible. With comparison the geo-referenced images and its articulation with the official IBGE maps, it was possible to draw the state maps with the equipment density distribution, which, when compared to other available sources permitted to validate the methodology used for this purpose.
Resonant tunneling through mixed quasibound states in a triple‐well structure

A triple‐well resonant‐tunneling structure made from the In0.53Ga0. 47As/AlAs material system yields a broad negative differential resistance (NDR) region without the precipitous drop in current that occurs in single‐well structures. This NDR characteristic is attributed to resonant tunneling through mixed quasibound states. A diode made from this structure is used to generate a nearly constant power of 0.5 mW up to 16 GHz.