Miracle-dz/UniFAR-FTUs huggingface dataset:
A simple model for polymeric fractals in a good solvent and an improved version of the Flory approximation

We define a r-fractal as a self-similar structure built from N basic units, and with a maximum gyration radius scaling like Nr. We assume that r is a superuniversal exponent, independent of the space dimension d and verifying 1/d≤r≤1. We determine the equilibrium fractal dimension, the spectral and spreading dimensions, etc. as a function of r and d. These r-fractals seem to offer a simple picture of actual polymers, with r = 1 for chains and r = 3/4 for branched polymers. We reinterpret the Flory approximation as giving an oversimplified expression for the statistical distribution of the gyration radius of r-fractals. The correct expression leads to an improved version of the Flory model, whose success is (tentatively) explained by the rather unexpected behaviour of an exponent ratio which stays very close to its ideal value in a wide range of r and d.
Biofiltration Control of Hydrogen Sulfide 1. Design and Operational Parameters

Laboratory scale biological filter systems for control of hydrogen sulfide (H2S) in waste gas have been studied and the optimum design and operating parameters determined. Extensive tests have been conducted to evaluate the effect of various filter bed operating parameters such as temperature, retention time, H2S concentration, and H2S loading rate. Variable properties of new and used composts such as sulfate content, acidity, and water content have been studied for their influence on H2S removal efficiency. The effects of compost particle size distribution on system pressure drop and the maximum H2S elimination capacity were examined. Biofiltration systems containing various types of yard waste compost as the filter material have been observed to remove hydrogen sulfide with efficiencies greater than 99.9 percent for H2S inlet concentrations in the range from 5 to 2650 ppmv.
Effect of Soil pH on Adsorption of Lead, Copper, Zinc, and Nickel

Lead, copper, nickel, and zinc adsorption by and desorption from pH-adjusted soils has been studied. Surface and subsurface horizon samples of two soils were equilibrated with varying amounts of Ca(OH)/sub 2/ prior to metal addition. The amount of all four metals retained was dependent upon pH of the soil sample, with retention dramatically increasing above pH 7.0 to 7.5. With the exception of Ni, at least 70 to 75% of the retained metal was extractable in 0.01N HCl. Nickel was somewhat less extractable, with that sorbed by the highest pH soils being the least extractable. Based on subsequent extractibility, the soils used appeared to have specific adsorption sites for Pb, Ni, and Cu but little or none for Zn. These studies cast some doubt on the concept of pH management for immobilizing heavy metals placed on the land in that sorbed metals were substantially extractable by 0.01M HCl, which has been used to estimate plant availability of soil ions.
Thermophilic (55–65 °C) and Extreme Thermophilic (70–80 °C) Sulfate Reduction in Methanol and Formate‐Fed UASB Reactors

The feasibility of thermophilic (55–65 °C) and extreme thermophilic (70–80 °C) sulfate‐reducing processes was investigated in three lab‐scale upflow anaerobic sludge bed (UASB) reactors fed with either methanol or formate as the sole substrates and inoculated with mesophilic granular sludge previously not exposed to high temperatures. Full methanol and formate degradation at temperatures up to, respectively, 70 and 75 °C, were achieved when operating UASB reactors fed with sulfate rich (COD/SO42‐ = 0.5) synthetic wastewater. Methane‐producing archaea (MPA) outcompeted sulfate‐reducing bacteria (SRB) in the formate‐fed UASB reactor at all temperatures tested (65–75 °C). In contrast, SRB outcompeted MPA in methanol‐fed UASB reactors at temperatures equal to or exceeding 65 °C, whereas strong competition between SRB and MPA was observed in these reactors at 55 °C. A short‐term (5 days) temperature increase from 55 to 65 °C was an effective strategy to suppress methanogenesis in methanol‐fed sulfidogenic UASB reactors operated at 55 °C. Methanol was found to be a suitable electron donor for sulfate‐reducing processes at a maximal temperature of 70 °C, with sulfide as the sole mineralization product of methanol degradation at that temperature.
BIOACCUMULATION OF HEAVY METALS BY EARTHWORM (LUMBRICUS TERRESTRIS) AND ASSOCIATED SOILS IN DOMESTIC DUMPSITE IN ABRAKA, DELTA STATE, NIGERIA

Metal concentrations in (earthworm) lumbricus Terrestris and soil samples from six domestic dumpsites located in Abraka Delta State, Nigeria were measure spectrophotometrically after sample digestion. Mean metal content in dumpsite soils were, 14.45-63.12, 1613.83-1967.70, 35.41-53.70, 10.81-73.10, 9.73-47.92, 80.17112. 13ug/g for Cr, Fe, Mn, Ni, Pb and Zn respectively. While the concentration ranges recorded in L. Terrestris samples were: 7.18-9.65, 347.22-355.76, 19.31-43.59, 3.12-12.64, 4.57-12.62, 53.57-74.52ug/g for Cr, Fe, Mn, Ni, Pb and Zn respectively. The biota–to-soil accumulation factors were all less than unity for all metals. The order of bioaccumulation of the metals followed the trend: Mn >Zn >Pb> Cr>Fe>Ni. The availability of metals in soil was also co-determined by the pH and soil organic matter which accounted for the trend of metal concentration at the various dumpsites. The pH of the soil samples ranged from 4.5-5.7 while organic matter ranged between 1.97-4.22% Since birds and domestic fowls fed on insects and L. Terrestris, transfer of these metals across the food chain are most probable.
Competition between photochemical and biological degradation of dissolved organic matter from the cyanobacteria Microcystis aeruginosa

Extracellular and intracellular dissolved organic matter (E‐DOM and I‐DOM, respectively) produced in axenic cultures by the cosmopolitan cyanobacteria Microcystis aeruginosa were characterized, and photoreactivity, bioreactivity, and the effects of phototransformations on bioavailability of E‐DOM and I‐DOM were assessed in laboratory experiments. Chromophoric (CDOM) and fluorescent (FDOM) properties were analyzed by spectrophotometry, and chemical signatures were obtained by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR‐MS). E‐DOM was more heterogeneous regarding optical characteristics as indicated by the presence of multiple CDOM peaks and the more even distribution of FDOM components, and had less absolute and relative numbers for molecular formulae containing nitrogen (N) than I‐DOM. E‐DOM was more photolabile, with greater photochemical removal of dissolved organic carbon (DOC), CDOM and FDOM, and exhibited more pronounced photochemical alterations in molecular formulae composition than I‐DOM. E‐DOM was less biolabile, with less biological removal of DOC, CDOM, and protein‐like fluorescent material, and supported lower rates of bacterial productivity than I‐DOM. Phototransformations reduced the bioavailability of E‐DOM and I‐DOM, as shown by lower bacterial productivity and longer DOC and CDOM half‐lives in bioassays with photoirradiated DOM in comparison to those with nonirradiated DOM. Analyses of CDOM, FDOM, and FTICR‐MS revealed that the decrease in bioavailability was caused primarily by photolysis of the biolabile DOM, indicating competition between photochemical and biological removal of cyanobacterial DOM. These results provided insights into mechanistic effects of independent and combined photochemical and biological degradation on M. aeruginosa‐derived DOM.
Large extinction effects in magnesium oxide

Integrated intensities from a large crystal of magnesium oxide are shown to be affected by primary extinction. The intensities are found to fit the solutions of the dynamic theory of X-ray diffraction for both the Laue and the Bragg cases. A mosaic block size of 3.56 × 10-3 cm has been found.
Kinetic parameters of soil β-glucosidase response to environmental temperature and moisture regimes

Soil β-glucosidase participates in the final step of cellulose biodegradation. It is significant in the soil C cycle and is used as an indicator of the biological fertility of soil. However, the response of its kinetic parameters to environmental temperature and moisture regimes is not well understood. This study tested the β-glucosidase response in the main agricultural soils (black soil, albic soil, brown soil, and cinnamon soil) of Northeast China. Incubation tests were conducted to measure the kinetic parameters Km, Vmax or Vmax/Km of soil β-glucosidase at environmental temperatures of 10, 20 and 30 oC and at 10, 20 and 30 % soil moisture content. The insensitive response of the kinetic parameters to temperature changes indicates that soil β-glucosidase was present primarily in immobilized form. The significant response of the kinetic parameters of soil β-glucosidase to soil moisture rather than to environmental temperatures suggests that the catalytic ability of soil β-glucosidase was sensitive to changing soil moisture regimes.
Complexation of platinum, palladium and rhodium with inorganic ligands in the environment

Platinum (Pt), palladium (Pd) and rhodium (Rh) are emitted by vehicle exhaust catalysts (VECs) and their concentrations have increased significantly in various environmental compartments, including airborne particulate matter, soil, roadside dust, vegetation, rivers and oceanic environments, over the last two decades as the use of VECs has increased. However, data on the chemical speciation of the platinum-group elements (PGEs) and their bioavailabilities are limited. In this paper, the thermodynamic computer model, HSC, has been used to predict the interactions of Pt, Pd and Rh with different inorganic ligands and to estimate the thermodynamic stability of these species in the environment. Eh–pH diagrams for the PGEs in aqueous systems under ambient conditions (25°C and 1 bar) in the presence of Cl, N and S species have been prepared. The results indicate that Pt, Pd and Rh can form complexes with all of the inorganic ions studied, suggesting that they are capable of mobilizing the PGEs as aqueous complexes that can be transported easily in environmental and biological systems and that are able to enter the food chain. Hydroxide species can contribute to the transport of PGEs in oxidizing environments such as road-runoff waters, freshwater, seawater and soil solutions, whereas bisulphide complexes could transport Pt and Pd in reducing environments. Ammonia species appear to be significant under near-neutral to basic oxidizing conditions. Chloride species are likely to be important under oxidizing, acidic and saline environments such as seawater and road-runoff waters in snowmelt conditions. Mixed ammonia–chloride species may also contribute to the transport of Pt and Pd in highly saline solutions.
The impact of engineered cobalt, iron, nickel and silver nanoparticles on soil bacterial diversity under field conditions

Our understanding of how engineered nanoparticles (NPs) migrate through soil and affect microbial communities is scarce. In the current study we examined how metal NPs, including those from the iron triad (iron, cobalt and nickel), moved through pots of soil maintained under winter field conditions for 50 days, when mesophilic bacteria may not be dividing. Based on total metal analysis, cobalt and nickel were localized in the top layer of soil, even after exposure to high precipitation and freeze–thaw cycles. In contrast, a bimodal distribution of silver was observed. Due to high endogenous levels of iron, the migration pattern of these NPs could not be determined. Pyrosequence analysis of the bacterial communities revealed that there was no significant engineered NP-mediated decline in microbial richness. However, analysis of individual genera showed that Sphingomonas and Lysobacter were represented by fewer sequences in horizons containing elevated metal levels whereas there was an increase in the numbers of Flavobacterium and Niastella. Collectively, the results indicate that along with the differential migration behavior of NPs in the soil matrix, their impact on soil bacterial diversity appears to be dependent on environmental parameters.
Diameter and helicity effects on static properties of water molecules confined in carbon nanotubes

The behavior of water in carbon nanotubes has recently received increasing attention since some theoretical work has shown that nanotubes have the potential to be used as proton-conducting pores for a variety of biological applications. The properties of a nanotube strongly depend on its diameter and helicity; therefore, their influences on the behavior of water molecules confined in carbon nanotubes have to be fully examined for a better understanding of nanotube's potential biological applications. In this work, molecular dynamics simulations were performed under ambient conditions for armchair and zigzag type nanotube segments of various diameters submerged in water. The results indicate that single-file water chains as the basis of fast proton conduction can be formed only in narrow nanotubes (0.676–0.811 nm diameter). The formation of ice-like water structures inside nanotubes might be sensitive to potential models and corresponding parameters. Obvious variation in average number of H-bonds per molecule can occur only in narrow carbon nanotubes, which is expected to significantly affect the diffusion rate of confined water. The extent of confinement phenomena is dominated by tube diameter. Tube helicity rarely affects the static properties of confined water.
Documentation and identification of medicinal plants traded in Tanzania by means of DNA barcoding.

Background Tanzania is rich in biodiversity and home to a lot of endemic plants that are used in treatment of diseases. The country continues to lose plant biodiversity through trade of medicinal plants. The medicinal plants are traded in the forms ranging from: raw state (leaves, bark and roots) to unprocessed fragmented materials (chips and slices), and semi-processed materials (powders, extracts and teas) which makes conventional identification challenging. In this study the use of DNA barcoding was trialled. Objectives The aim of this study was to identify medicinal plants that are trade in Tanzania by means of DNA barcoding. Methodology A total of 78 respondents were obtained using the “snowball” technique and personal communication. Data collected was done through local market survey using semi-structured questionnaire, botanical collection, literatures, and laboratory works. Microsoft Excel ware used to structure frequencies, percentage and figures. Result There is trade in medicinal plants in Dar-es-Salaam and Tanga regions. Most of these medicinal plants are collected from Coast, Tanga and Arusha regions. The trade is much on most important medicinal plants in the markets which include Zanthoxylum chalybeum Engl. , Zanha africana (Radlk.) Exell, Cassia abbreviata Oliv. , Albizia anthelmintica Brongn. , Hymenaea verrucosa Gaertn. , Rapanaea melanocephalus and Ximenia aegyptiaca L. Threat to medicinal plants have been much on most important plants in the market and those affected through debarking which include: Albizia anthelmintica in Bwawa village and Afzelia quanzensis. , Hymenaea verrucosa. and Pterocarpus bussei. Human activities have also impacted on the availability of medicinal plants.
Molecular modeling simulation and experimental measurements to characterize chitosan and poly(vinyl pyrrolidone) blend interactions

Blends of chitosan and poly(vinyl pyrrolidone) (PVP) have a high potential for use in various biomedical applications and in advanced drug-delivery systems. Recently, the physical and chemical properties of these blends have been extensively characterized. However, the molecular interaction between these two polymers is not fully understood. In this study, the intermolecular interaction between chitosan and PVP was experimentally investigated using 13C cross-polarization magic angle-spinning nuclear magnetic resonance (13C CP/MAS NMR) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). According to these experimental results, the interaction between the polymers takes place through the carbonyl group of PVP and either the OHC6, OHC3, or NHC2 of chitosan. In an attempt to identify the interacting groups of these polymers, molecular modeling simulation was performed. Molecular simulation was able to clarify that the hydrogen atom of OHC6 of chitosan was the most favorable site to form hydrogen bonding with the oxygen atom of CO of PVP, followed by that of OHC3, whereas that of NHC2 was the weakest proton donor group. The nitrogen atom of PVP was not involved in the intermolecular interaction between these polymers. Furthermore, the interactions between these polymers are higher when PVP concentrations are lower, and interactions decrease with increasing amounts of PVP. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1258–1264, 2008
Simultaneous Electrochemical Determination of Indole-3-acetic Acid and Salicylic Acid in Pea Roots using a Multiwalled Carbon Nanotube Modified Electrode

Indole-3-acetic acid and salicylic acid are essential phytohormones with profound effects on growth and development as well as stress responses of plants. Accumulating evidence has suggested that these compounds mediate the same biological process by collaboration or antagonistic actions. Simultaneous determination of indole-3-acetic acid and salicylic acid may significantly improve the understanding on mechanisms of their interaction. In this study, the simultaneous determination of these analytes was electrochemically performed using a multiwalled carbon nanotubes-chitosan modified glassy carbon electrode. Based on differential pulse voltammetry, indole-3-acetic acid and salicylic acid were determined from 0.67 to 48.82 micromolar with detection limits of 0.1 micromolar. In addition, no interferences were observed from other molecules. This method was employed for the simultaneous determination of the analytes in pea root extracts. The approach may be extended for additional study of the interaction of indole-3-acetic acid and salicylic acid in plants.
Nutritional Composition of a Non-Alcoholic Beverage Spiced with Zingiber officinale Extract Produced from Sorghum bicolor Stem Sheath

The fo rmulated beverage samples with ginger extract were analysed to determine its nutrient profile: pro ximate and mineral contents. Pro ximate analysis of the spiced stem sheath beverage revealed that the beverage is a nutrient dense commodity with health pro moting substances with high level of protein and fat : the mo isture content ranged between 87.890-88.360%, crude protein ranged between 0.092-0.052% and crude fat fro m 0.190-0.150% while p H and TTA were 7 and 4 respectively. The plain beverage sample had the least protein and fat content. High mineral contents were recorded for the spiced beverage samples: magnesium ranged between 145.00 -220.200mg/ 100ml, sodiu m ranged between 25.200-26.580mg/100ml, potassium ranged between 23.025 -30.950mg/100ml,calciu m 50.000-50.045mg/100ml, iron 4.000-5.340mg/100ml, zinc 2.500-3.170mg/100ml, manganese 0.380-1.730 and copper 0.0605-0.071mg/ 100ml while the plain beverage sample had the least mineral content. The nutrient profile increased significantly at (p < 0.05) with th e addition of ginger, the degree of enhancement was dependent on the concentration of the spice. The overall sensory evaluation revealed that acceptability was in order of 0.5% ext ract of g inger being the best preferred by the panellists.
Factors Affecting Scale Formation in Sea Water Environments – An Experimental Approach

Sea water is a complex aqueous environment with a large tendency for scale formation, which is usually ascribed to scaling from dissolved salts and suspended particles. Scale formation is causing many problems in thermal processes such as desalination and steam generation plants. In a typical desalination plant, ca. 40 % of the heat transfer area is provided to allow for scale formation problems, which is equivalent to a ca. 10 % increase of the whole capital cost of the plant. The main constituents forming scale in sea water environments, i.e., calcium carbonate, calcium sulfate and magnesium hydroxide, are extensively investigated in the present work. In order to obtain a better understanding of the scaling tendency of the seawater environment, an experimental unit was precisely designed and coupled with a data acquisition system for continuous monitoring of the investigated parameters. Significant factors affecting scale formation such as concentration of salts, flow velocity, water temperature and pH of the environments were studied at length using mild steel and stainless steel (smooth and rough). Hydrodynamic parameters such as Reynolds number and shear stress were used in the analysis of the collected data and revealed the role of shear stress in the effective removal of scale. The Kern-Seaton scale model was used to calculate the fouling resistance in each case and the values obtained were compared with the experimental results. A modification of this model was also undertaken to provide better agreement with experimental findings.
Global monthly CO2 flux inversion with a focus over North America

A nested inverse modelling system was developed for estimating carbon fluxes of 30 regions in North America and 20 regions for the rest of the globe. Monthly inverse modelling was conducted using CO2 concentration measurements of 3 yr (2001–2003) at 88 sites. Inversion results show that in 2003 the global carbon sink is -2.76 ± 0.55 Pg C. Oceans and lands are responsible for 88.5% and 11.5% of the sink, respectively. Northern lands are the largest sinks with North America contributing a sink of -0.97 ± 0.21 Pg C in 2003, of which Canada’s sink is -0.34 ± 0.14 Pg C. For Canada, the inverse results show a spatial pattern in agreement, for the most part, with a carbon source and sink distribution map previously derived through ecosystem modelling. However, discrepancies in the spatial pattern and in flux magnitude between these two estimates exist in certain regions. Numerical experiments with a full covariance matrix, with the consideration of the error structure of the a priori flux field based on meteorological variables among the 30 North America regions, resulted in a small but meaningful improvement in the inverted fluxes. Uncertainty reduction analysis suggests that new observation sites are still needed to further improve the inversion for these 30 regions in North America.
Liquid ChromatographyTandem Mass Spectrometry for Simultaneous Determination of Ticarcillin and Vancomycin in Presence of DegradationProducts. Application to the Chemical Stability Monitoring of Ticarcillin-Vancomycin Solutions

Acute bacterial conjunctivitis and their complications are commonly treated by 6 mg/mL ticarcillin and 50 mg/mL vancomycin eyes drops, formulated separately in hospitals. A rapid, selective and specific LC-tandem MS method has been developed and validated for simultaneous quantification of ticarcillin and vancomycinin solution and in presence of degradation products. Atlantis® C18 Column T3 (250×4.6 mm I.D., 5 μm) and gradient mobile phase composed of 44 mM trifluoracetic acid/methanol allowed for good separation. Degradation products were separated on LC and detected with mass spectrometry in full scan mode. The method was suitable forthe stability study of ticarcillin-vancomycin pH 5.2 solutionsover an 8-day period storage at 5 ± 3°C and at room temperature (25 ± 2°C). The solutions remained stable up to 5 days at 5 ± 3°C. At room temperature, degradation of ticarcillin was accelerated in presence of vancomycin, while vancomycin stability was not further affected by ticarcillin. High-resolution mass spectrometry was used for the characterization of the degradation products.