Miracle-dz/UniFAR-FTUs huggingface dataset:
Highly mesoporous α-Fe2O3 nanostructures: preparation, characterization and improved photocatalytic performance towards Rhodamine B (RhB)

Single-crystalline porous hematite nanorods and spindle-like nanostructures were successfully synthesized by a low temperature reflux condensation method. Two different iron sources, namely, FeCl3·6H2O and Fe(NO3)3·9H2O, were hydrolyzed in the presence of urea to selectively prepare nanorods and spindle-like nanostructures. Initially, the akagenite phase was obtained by refluxing the precursor for 12 h and then the as-prepared akagenite nanostructures were transformed to porous hematite nanostructures upon calcination at 300 °C for 1 h. The shape and the aspect ratio of the 12 h refluxed sample was retained even after calcination and this shows the topotactic transformation of the nanostructure. TEM and HRTEM investigations have shown the porous nature of the prepared sample. Brunauer–Emmett–Teller and Barret–Joyner–Halenda measurements have shown a large surface area and distribution of mesopores in the nanorods sample. The photocatalytic activity of the prepared nanostructures towards RhB has reflected this variation in the pore size distribution and specific surface area, by showing a higher activity for the nanorods sample. Magnetic studies by VSM have shown a weak ferromagnetic behaviour in both the samples due to shape anisotropy.
Development and Optimization of a Procedure for the Determination of Indium-Tin Oxide Particle Size and Concentration in Cellular Media

Indium-tin oxide (ITO) is a solid mixture often comprised of approximately 90% indium oxide and 10% tin oxide by weight. ITO is employed as a transparent conductive coating for flat panel, liquid crystal, and plasma displays and is typically deposited after sintering as a thin film on a substrate through a variety of processes. Unfortunately, there have been published reports of workers who have been adversely impacted through exposure to this compound. When these reports are coupled with the industrial utility of ITO, future toxicological investigations are likely. Comprehensive characterization of ITO test materials would be an essential component of these studies. Ideally, characterization would include assessment of ITO particle size as administered during dosing because this physicochemical parameter can significantly impact solubility. The objective of this task was to develop, optimize, and apply a dynamic light scattering (DLS) sample preparation and measurement protocol for determination of particle size for a suite of sintered/non-sintered ITO samples prepared in cellular growth media at nominal 0.3 mg/mL doses. Sonication time was evaluated from 15 to 90 minutes over a 24-hour, continuous DLS measurement period. Resulting suspensions from samples subjected to 30 minute sonication times were stable with respect to hydrodynamic particle size between 10 and 24 hours after sonication. Throughout the 24-hour DLS measurement period, suspension aliquots were analyzed by inductively coupled plasma mass spectrometry to determine indium concentration. The developed protocol enabled investigators to use ITO suspensions of known hydrodynamic particle size and concentration in their in vitro cellular study.
A potential new isolate for the production of a thermostable extracellular - amylase

Two hundred and seventy Bacillus species were isolated from soil samples in Khartoum State and tested for α- amylase production. 20 potential isolates of α- amylase producer were obtained during primary screening. Secondary screening of these isolates yielded a high thermostable alkaline α- amylase producing isolate. Of all the species tested, Bacillus licheniformis gave maximum α-amylase activity of 0.7947 U/mg/ml at pH of 8 in iodine method, and (0.024 U/mg/ml) in 3.5. dinitrosalicylic acid (DNS) method. Characterization of the extra-cellular crude α- amylase was further evaluated for its biochemical properties as an enzyme for industrial use. The production of α- amylase following growth of the microorganism was found to be at optimum temperature and pH of 70°C and 9.0, respectively. Key words: Thermostable α- amylase, alkaline α- amylase, Bacillus licheniformis.
Microdomain composition and properties differences of biodegradable polyurethanes based on MDI and HDI

The study of the effect of the diisocyanate structure on the microstructure and macroscopic properties of polyurethanes was the main aim of this work. Biodegradable segmented thermoplastic elastomeric polyurethanes based on a poly(hexamethylene carbonate-co-caprolactone)diol (PHM-co-PCL) as soft segment were synthesized using 1,4-butanediol (BD) as chain extender and both 4,4′-diphenylmethane diisocyanate (MDI) and 1,6-hexamethylene diisocyanate (HDI) as components of the hard segment by the two shoot synthesis procedure. Microphase structure and properties were analyzed using Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) as complementary techniques, used to characterize thermal transitions of the polyurethanes and to assign them to determinate functional groups interactions. Gaussian deconvolution technique was used to decompose carbonyl region in four peaks and to study the hydrogen bonding within the different polyurethanes. Both DSC and FTIR showed that MDI-based biodegradable polyurethanes were less phase segregated than to those based on HDI, and thus that diisocyanate structure has an important role on microdomain composition and polyurethanes properties. Macroscopic properties as hardness and water-polymer contact angles are related to polyurethanes microphase compositions. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.
Insights into the P-to-Q conversion in the catalytic cycle of methane monooxygenase from a synthetic model system

For the catalytic cycle of soluble methane monooxygenase (sMMO), it has been proposed that cleavage of the O–O bond in the (μ-peroxo)diiron(III) intermediate P gives rise to the diiron(IV) intermediate Q with an Fe2(μ–O)2 diamond core, which oxidizes methane to methanol. As a model for this conversion, (μ–oxo) diiron(III) complex 1 ([FeIII2(μ–O)(μ–O2H3)(L)2]3+, L = tris(3,5-dimethyl-4-methoxypyridyl-2-methyl)amine) has been treated consecutively with one eq of H2O2 and one eq of HClO4 to form 3 ([FeIV2(μ–O)2(L)2]4+). In the course of this reaction a new species, 2, can be observed before the protonation step; 2 gives rise to a cationic peak cluster by ESI-MS at m/z 1,399, corresponding to the {[Fe2O3L2H](OTf)2}+ ion in which 1 oxygen atom derives from 1 and the other two originate from H2O2. Mössbauer studies of 2 reveal the presence of two distinct, exchange coupled iron(IV) centers, and EXAFS fits indicate a short Fe–O bond at 1.66 Å and an Fe–Fe distance of 3.32 Å. Taken together, the spectroscopic data point to an HO-FeIV-O-FeIV = O core for 2. Protonation of 2 results in the loss of H2O and the formation of 3. Isotope labeling experiments show that the [FeIV2(μ–O)2] core of 3 can incorporate both oxygen atoms from H2O2. The reactions described here serve as the only biomimetic precedent for the conversion of intermediates P to Q in the sMMO reaction cycle and shed light on how a peroxodiiron(III) unit can transform into an [FeIV2(μ–O)2] core.
In-vitro evaluation of the antimicrobial activity of extracts of Bridelia micrantha on selected bacterial pathogens

Medicinal plants have been age long remedies for human diseases because they contain components of therapeutic value. In this study, six solvent extracts [dichloromethane, ethyl acetate, acetone, ethanol, methanol (100%), and 40% methanol hydroxide] of the stem bark of Bridelia micrantha and ciprofloxacin were investigated for antimicrobial activity by the agar-well diffusion method against strains of Staphylococcus aureus NCTC 6571 , Shigella sonnei ATCC 29930, Salmonella typhimurium ATCC 13311, Helicobacter pylori ATCC 43526, and Helicobacter pylori 252c. The most active extracts were assayed for MIC 50 using the 96-well microdilution technique and one way ANOVA test was used to determine if there was any statistically significant difference in the MIC 50 of the most active extracts and the control antibiotic (ciprofloxacin). Results obtained indicated that methanol was quantitatively the best solvent for extraction, while ethyl acetate was the least. Zone diameters of inhibition ranged from 0 to 28 mm for the six extracts and 29 to 38 mm for ciprofloxacin. Ethyl acetate and acetone extracts were the most active of all the extracts exhibiting a broad spectrum activity. However, Gram-positive bacteria were more sensitive compared to Gram-negative bacteria. The MIC 50 value ranged from 0.078 to 1.25 mg/ml and 0.078 to 0.625 mg/ml for the acetone and ethyl acetate extracts respectively, with no statistically significant difference in potency (p value = 0.187) when compared to ciprofloxacin. Our findings demonstrate the in-vitro antibacterial activity of the crude extracts of B. micrantha , and therefore provide preliminary scientific evidence to justify the use of the plant in traditional medicine.
In Vivo Studies of Aerosolized Exogenous Surfactant

Exogenous surfactant administration is currently being investigated in patients with the adult respiratory distress syndrome CARDS). Several animal studies and recent clinical experience suggest that this therapy has promise. Currently, the optimal method of delivery is unknown. Both instillation of large doses of exogenous surfactant as well as aerosolization with small quantities of surfactant deposited in lung tissue have been evaluated. Both methods of delivery have significantly improved lung function in animal models of lung injury and are currently being evaluated in multicenter clinical trials. From the animal model of lung injury in which injury was induced by repetitive saline lung lavage, it has been shown that aerosolized surfactant was, in some cases, superior to instilled surfactant. With improvements in technology resulting in increased aerosolized surfactant deposition within lung tissue, consistent improvements in physiologic parameters have been shown suggesting a dose-response phenomeno.
Contact Potential Difference Measurements by the Kelvin Method

Measurements of contact potential differences between clean metallic surfaces produced by condensation from the vapour, by the vibrating condenser modification of the Kelvin method, yield the following values for average work functions, on the basis of an assumed value of 4.565 ± 0.025 eV for the work function of tungsten: copper, 4.52 ± 0.04 eV; silver, 4.31 ± 0.03 eV; gold, 4.70 ± 0.03 eV, aluminium, 4.20 ± 0.05 eV; nickel, 4.74 ± 0.04 eV; molybdenum, 4.22 ± 0.05 eV; iron, 4.17 ± 0.03 eV. The lack of contamination and the reproducibility of results are attributed to the use of molybdenum gettering films, and to the outgassing procedures employed.
The novel azomethine ligands for binuclear copper(II) complexes with ferro- and antiferromagnetic properties

A series of novel binuclear ferro- and antiferromagnetic Cu(2+) chelates of structurally broadly varied Schiff bases (derived from o-tosylamino(hydroxyl)benzaldehydes and monoalkylated o-phenylenediamine, o-aminophenol, o-aminothiophenol, 1,2-diaminobenzimidazole, 1-aminobenzimidazoline-2-thione) and β-diketimines (derived from 2,6-di-i-Pr-aniline) has been prepared. The tautomerism of the ligands and structureof their copper complexes have been studied with the use of IR, 1H NMR EPR and EXAFS spectroscopy. Molecular and crystal structure of a β-diketimine copper dimer has been determined by X-ray crystallography. The magnetic measurements (2–300 K) performed for all the complexes showed that the ferro- and antiferromagnetic character of the exchange interaction depends both on the structure of the coordination site (origin of the ligating centers) and the structure of the ligands (in particular, on the type of the cycle annelated to the bridging fragment). Whereas S-binding metal chelates 13 (X = NTs, Y = S, R = H) are diamagnetic, the complexes 15 with annelated azole moieties are ferromagnetic.
Electronegativity of Radicals. A Method of Calculation

Gordy's expression, relating the electronegativity of an atom with the number of electrons in the valence shell and the covalent bond radius, has been extended to the calculation of the group electronegativity of a radical. Both the state of hybridization and the effect of the electronegativity property of other atoms on the bonding atom in the radical have been accounted for. The group electronegativities calculated by this expression are in agreement with those obtained from the ``sensitive'' CH bending vibrational frequencies, but disagree with group electronegativities obtained from other spectroscopic data. The causes of these differences have been discussed.
Decomposition of Anionic Surface Active Substances by Bacteria from the Surface Microlayer of Lake Jeziorak Mały

The concentration of anionic surface active substances (ASAS) in the water of Lake Jeziorak Maly and the degradation of these substances by bacteria isolated from the surface microlayer and subsurface water were the object of the research of this paper. The concentrations of ASAS in water of this lake were at the level of about 2 mg/1. The biodegradation of ASAS was performed twice as well by microorganisms from the surface microlayer than from subsurface water. Moreover, within the surface microlayer the process of decomposing ASAS was most effectively performed by bacteria isolated from the layers of water closest to the surface (100-150 µm).
Polyelectrolyte Moderated Interactions between Glass and Cellulose Surfaces

This thesis concentrates on the effect of cationic polyelectrolyte addition on the interactions between inorganic and model cellulose surfaces in aqueous solutions. An effort was made to link the physicochemical properties of the polyelectrolytes, such as charge density, molecular mass and architecture to the type of interactions they generate upon adsorption to glass and cellulose. The Langmuir-Blodgett deposition technique was used in order to prepare thin, molecularly smooth cellulose films on hydrophobized mica substrates. The low surface roughness of the model cellulose surface allowed accurate surface force determination at any separation, down to surface contact. Flame polished, borosilicate glass was used as an inorganic surface. As a force-measuring device, the non-interferometric surface force apparatus (MASIF) was selected for its ability to handle a large variety of surface materials and fast data acquisition. As a rule, force measurements were performed first at zero polyelectrolyte addition, i.e. in polyelectrolyte-free salt solutions. From these measurements the surface charge density of the studied substrates could be determined by fitting DLVO-theory to the experimental force profiles. The cellulose surface was found to be weakly negatively charged. The slow swelling of the cellulose film could also be detected from the force data. All studied polyelectrolytes adsorb on glass and cellulose, causing charge neutralization at very low bulk concentration (1 ppm). At the charge neutralization point a bridging attraction is found for highly charged polyelectrolytes. This is followed by charge reversal at higher concentrations. The magnitude of this charge reversal was dependant on the polyelectrolyte structure and charge density, as well as on the charge density of the substrate surface. For the particular case of weakly charged polyelectrolyte AM-MAPTAC 10 adsorbing on cellulose surfaces the interaction was dominated by a long-ranged steric force due to the large thickness of the adsorbed polymer layer. In other investigations, the forces between surfaces asymmetrically coated with polyelectrolytes were investigated and found to be attractive at large separations. Possible electrostatic and polymer-induced effects are considered as a cause of the long-ranged attraction in these cases. Additional information about the surface properties of glass, cellulose and other substrates was obtained by studying the adhesion in air between these substrates and hemispherical PDMS caps employing the JKR method. Data for the work of adhesion was collected and shown to be in a good agreement with calculated values. Both glass and cellulose exhibited a hysteresis between loading and unloading cycles. The result was discussed in terms of surface layer interpenetration and formation of chemical bonds between reactive surface groups.
Conformations and dynamics of dendrimers and cascade macromolecules

The Rouse–Zimm discrete hydrodynamic model is extended to acyclic macromolecules of any topology, and particular attention is devoted to starlike dendrimers and other symmetric cascade structures. As a first approximation, freely rotating models are built for branched structures by means of appropriate choices of topology-dependent stiffness parameters. Relevant dynamic observables (depending on the spectrum of viscoelastic relaxation rates) are studied as functions of local stiffness, of branching topology, and of dendrimer generational growth. The present results show that a moderate increase of local stiffness accounts for the molecular dimensions of dendrimers as previously calculated by Mansfield and Klushin [J. Phys. Chem. 96, 3994 (1992)] by Monte Carlo methods, and reproduces with good precision their results for the intrinsic viscosity (upper-bound calculations). Thus omission of excluded-volume interactions within the present models can be at least partially compensated for by suitable choices of local stiffness parameters, provided that the chain portions between branching points are not very long. In addition, the inaccuracy caused by preaveraging of hydrodynamic interactions (as estimated by computing exact and preaveraged first cumulant of the structure factor) does not seem to obscure the essential conclusions.
Assessment of exchange-correlation functionals for the calculation of dynamical properties of small clusters in time-dependent density functional theory

We present a detailed study of different exchange-correlation ~xc! functionals in describing the dynamical properties of finite systems. For that purpose, we calculated the static polarizabilities, ionization potentials, and optical absorption spectrum of four small clusters, Na 2 ,N a 4, SiH4, and Si2H6, using a real-space, real-time technique. The computed static polarizabilities and ionization potentials seem to be in rather good agreement with the available experimental data, once the proper asymptotics of the potential are taken into account. The same conclusion holds for the absorption spectra, although the xc kernels in use do not provide a sufficiently strong attractive interaction between electrons and holes, leading to spectra slightly shifted towards higher energies. This deficiency is traced back to the insufficient description of dynamical effects in the correlation functional. Furthermore, it is shown that the xc potential used to obtain the ground state is the key factor to get reasonable spectra, whereas the choice of the xc kernel just amounts to small, although important, quantitative changes. © 2001 American Institute of Physics. @DOI: 10.1063/1.1385368#
Trend and Spatial Distribution of Air Particulate Matter Pollution in Dhaka City

From the air particle (PM) collected from different locations of Dhaka city it has been found that about 30 - 50% of the PM 10 mass (depending on location) is fine particles with aerodynamic diameter less than 2.2 μm, which are mainly of anthropogenic origin and predominately from transport related sources. On the other hand, due to the meteorological reason and long-range transport during the wintertime, the PM concentrations remain much higher than the Bangladesh National Ambient Air Quality Standard (NAAQS). Key words: Spatial distribution; Air particulate matter; Pollution DOI: 10.3329/jbas.v34i1. 5490 Journal of Bangladesh Academy of Sciences , Vol.34, No.1, 33-48, 2010
Zinc Requirement of Maize Hybrids and Indigenous Varieties on Udic Haplustalf

ABSTRACT A pot study was conducted on Gujranwala series (Udic Haplustalf) to compare zinc (Zn) requirement of maize hybrids (FHY- 456, FHY- 396, and FHY- 421) and indigenous varieties (EV-1089, Golden, and Soneri). Uniform rates of nitrogen:phosphorus:potassium (N:P:K) and four rates of Zn were applied in triplicate according to CRD. There was a significant (P < 0.05) main and interactive effect of maize genotypes and zinc application on shoot growth and Zn uptake. The three maize varieties uniformly produced maximum shoot dry weight at 3 mg Zn kg−1 soil. The maize hybrids produced maximum shoot dry weight at 9 mg Zn applied kg−1 soil. A 6.3 mg Zn kg−1 plant tissue was optimum for FHY-421 (hybrid) and 9.5 mg Zn kg−1 plant tissue was optimum for Soneri (variety). Hence, more pronounced response in maize hybrids than indigenous varieties require higher rates of Zn application. However, further verification of the results is warranted under field conditions.
Sorption of Zinc and Iron in Soils of Selected Areas in Southern Ethiopia

Sorption is one of the most important chemical processes in soils that determine the quantity of plant nutrients retained on soil surfaces and, therefore, affect transport of nutrients and regulate the concentration of nutrients in soil solution. A study was conducted in soils of Zeway, Alage, Butajira, Hawassa Zuria, Halaba and Taba in southern Ethiopia with the objective of evaluating the extent of Zn and Fe sorption. Surface soils (0-30cm depth) from the sites were collected, air dried and analyzed for particle size distribution, pH, EC, CEC, organic C, calcium carbonate equivalent, macro and micro nutrients using standard procedures. A 0.5 g soil sample was placed in a 100 ml plastic bottle and equilibrated with 0.01 M CaCl 2 overnight using a soil/solution ratio of 1:50 to determine the sorption of Zn and Fe. Stock solutions of ZnSO 4 and FeSO 4 with concentrations of 0, 2, 5, 10, 15 and 30 mg L -1 Zn Fe respectively were mixed with the soil-0.01 M CaCl 2 solution and equilibrated for 24 hours. The suspension was filtered, and the concentrations of Zn and Fe in the clear extract solution were determined using Atomic Absorption Spectrophotometer. The Langmuir and Freundlich adsorption equations were applied to determine the sorption relationships. The results indicated that the soils differ in physicochemical characteristics as well as Zn and Fe sorption capacities. Additionally, sorptions of the two micronutrients were high in all soils, except that of Zn in Hawassa soils, where added Zn was remained in the soil solution. Sorptions of Zn and Fe in the experimental soils followed Langmuir and Freundlich models, respectively. Zn adsorption was strongly related with soil organic carbon, calcium carbonate, iron and manganese contents of the soils, whereas iron was strongly related to clay. Fertilizer management for optimum crop production should therefore consider inclusion of Zn and Fe in the experimental sites, except Zn at Hawassa. Keywords: Freundlich, Iron, Isotherms, Langmuir, Sorption, Zinc