Miracle-dz/UniFAR-FTUs huggingface dataset:
ARTHROPOD ALKALOIDS IN POISON FROGS : A REVIEW OF THE 'DIETARY HYPOTHESIS'

Poison frogs are chemically defended from predators and/or microorganisms by the presence of alkaloids in dermal skin glands. Over the past 40 years, more than 800 alkaloids, which are generally organized into 28 structural classes, have been identified in several lineages of poison frogs worldwide. Originally, the presence of alkaloids in frogs was thought to be the result of biosynthesis, however research led largely by John W. Daly resulted in the discovery that most of these alkaloids are sequestered unchanged from dietary arthropods. In the present paper, we review the most significant findings and studies that led to the proposal of the 'dietary hypothesis'.
Antimicrobial efficacy, cytotoxicity, and ion release of mixed metal (Ag, Cu, Zn, Mg) nanoparticle polymer composite implant material

Abstract Medical devices made of polymers are often protected against infection-relevant biofilm formation by embedding nanoparticles as a source of bioactive metal ion release. Safe application of such nanocomposites requires finding the optimal ion dose and identifying the cross-effects caused by material mixtures. This study investigated the safety and antimicrobial efficacy of thermoplastic polyurethane (TPU), which is widely used for medical devices, e.g., catheters containing zinc, silver, copper and magnesium nanoparticles, respectively, and combinations thereof. Nanoparticles were generated by using pulsed laser ablation in polymer solution. We found that the composites embedded with nanosilver were noncytotoxic to cells but toxic to bacteria, with an optimal effect at 0.5 wt%. In contrast, zinc, copper, and magnesium nanoparticle composites did not inhibit bacteria growth. Interestingly, by combining the antibacterial metals (Ag, Cu) with nanoparticles made of elements required in biological systems (Zn, Mg), we observed an altered ion release and corresponding changes to their antibacterial efficacy and biocompatibility. The combination of silver with magnesium in the nanocomposites did increase both the amount and rate of silver ion release, and resulted in an increased antimicrobial effect of this Ag-Mg-TPU composite material. The therapeutic window of silver could not be changed quantitatively by the Ag-Mg combination, but less wt% silver was required for achieving antimicrobial efficacy because of faster ion release in the clinically relevant, critical initial phase of immersion. According to our observations, the mechanism of Mg increasing the mass-specific bio-effectivity of silver is possibly nonelectrochemical but volumetric. A fine-tuning of the Mg to Ag ratio and the overall load would be required to test whether a larger therapeutic window compared with Ag composites can be gained by the mixed Mg-Ag nanocomposites. Overall, the addition of Mg to Ag reduces the lag phase of bioactivity by increasing the Ag ion release in the critical first days after application of the medical device.
Stacking fault model of ∊-martensite and its DIFFaX implementation

Plastic deformation of highly alloyed austenitic transformation-induced plasticity (TRIP) steels with low stacking fault energy leads typically to the formation of ∊-martensite within the original austenite. The ∊-martensite is often described as a phase having a hexagonal close-packed crystal structure. In this contribution, an alternative structure model is presented that describes ∊-martensite embedded in the austenitic matrix via clustering of stacking faults in austenite. The applicability of the model was tested on experimental X-ray diffraction data measured on a CrMnNi TRIP steel after 15% compression. The model of clustered stacking faults was implemented in the DIFFaX routine; the faulted austenite and ∊-martensite were represented by different stacking fault arrangements. The probabilities of the respective stacking fault arrangements were obtained from fitting the simulated X-ray diffraction patterns to the experimental data. The reliability of the model was proven by scanning and transmission electron microscopy. For visualization of the clusters of stacking faults, the scanning electron microscopy employed electron channelling contrast imaging and electron backscatter diffraction.
Trägerbeweglichkeit in verformtem Germanium

Die Hallbeweglichkeit schwach dotierter Germaniumeinkristalle wurde vor und nach plastischer Verformung zwischen 50 und 250 °K gemessen. Die streuenden Verformungszentren wurden als Versetzungen identifiziert, die durch ihre Ladung und ihr Verschiebungsfeld die Beweglichkeit freier Locher beeinflussen. Zur Bestimmung der Ladung der Versetzung wurde das Modell des Versetzungsbandes herangezogen. Die Ergebnisse der Beweglichkeitsmessung wurden unter der Annahme analysiert, das freie Locher bzw. ionisierte Fremdatome die Versetzungsladung abschirmen. The Hall mobility of weakly doped germanium single crystals has been measured before and after plastic deformation at temperatures between 50 and 250 °K. The scattering centres introduced by deformation were identified to be dislocations acting on free holes by means of their charge and their strain field. The model of the dislocation band was used to determine the charge of the dislocation. The mobility results were analysed under the assumption that screening of the charge of the dislocation is done by free holes or ionized impurities.
Chemical composition of monsoon rains over Calcutta. Part I

Monsoon rainwater over Calcutta was analysed for Na, K, Ca, Mg, Cl, SO 4 , HCO 3 , NO 3 , pH, SiO 2 , B and Fe. The data shows that the dissolved mineral content is greatly affected by meteorological conditions viz. intensity, quantity and interval between various showers as well as wind velocity (cyclonic weather). Amongst the ions bicarbonate ions are quite prominent, particularly when rainfall is low. The sulphate ions generally exceed the chloride ions. The origin of the various constituents is also discussed. DOI: 10.1111/j.2153-3490.1969. tb00421.x
Steam Stripping of Bromine from Sea Brine: Mass-Transfer Analysis of Randomly Packed Columns

Abstract Mass transfer data have been collected on stripping of bromine from aqueous solution at different flow rates of liquid and steam using Rasching and Pall Ring packings randomly packed in glass columns (6.25 to 90 cm diameter) and tower constructed by using granite slabs having square cross-section (25 cm × 25 cm). In the present study, the model proposed by Wagner et al. [1] for distillation considering gas phase resistance as the controlling resistance is modified wherein liquid phase resistance is considered as the controlling resistance for mass-transfer. The modified model and model proposed by Castillo et al. [2] for stripping of volatile organic compounds (VOCs) from water have been successfully applied to the experimental data on debromination of sea brine. Average deviation between observed and calculated value of height of transfer unit based on the modified model of Wagner et al. [1] is 20.9 and 10.7% for bromide-bromate solution and bittern, respectively. The average deviation between observed and calculated overall volumetric liquid phase mass transfer coefficient is 16.62, 15.13 and 84.19% for debromination of bittern using pilot plant data, commercial bromine plants, and sodium bromide-bromate solution, respectively, based on correlations given by Wagner et al. [1]. Similar results based on Castillo et al. [2] model are 34.43, 49.69 and 26.80%, respectively. Volumetric liquid phase mass transfer coefficient for stripping of VOCs from water is in the range of 0.001-0.008 (1/s) whereas in the present study it varies from 0.001 to 0.017 (1/s). In other words, steam stripping of bromine from aqueous systems appears comparatively easier than stripping of VOCs from water.
Influence of hydrodynamic conditions on the production and fate of Posidonia oceanica in a semi-enclosed shallow basin (Stagnone di Marsala, Western Sicily)

An integrated approach using hydrodynamic and transport numerical models, lepidochronology and stable isotope analysis was used to investigate how local hydrodynamic conditions influence the primary production and fate of the seagrass Posidonia oceanica in a Mediterranean semi-enclosed marine system (Stagnone di Marsala). The water mass exchange aptitude of different sectors of the basin was analysed, and data collected were used to select two sectors (colonized by Posidonia oceanica showing the lowest and highest water exchange values) for biological analyses. According to the mean dispersal coefficient differences simulated by the hydrodynamic model, growth rate and primary production of P. oceanica differed between sectors, with average values lower in the central sector where water exchange is lower than in the southern sector. Although P. oceanica coverage and primary production were higher in the southern sector, carbon and nitrogen stable isotope analysis suggests that the transfer of seagrass organic matter to higher trophic levels of the food web was higher in the central sector. The possibility of a link between hydrodynamism, production and fate of organic matter is proposed to explain the observed patterns.
Biological minerals formed from strontium and barium sulphates. II. Crystallography and control of mineral morphology in desmids

The crystallography and morphology of barium sulphate crystals produced by a range of desmid species have been examined by electron microscopy and electron diffraction. The morphology of the BaSO4 crystals varies between desmid species and water chemistry. Tabular, rhombic crystals are commonly produced by Closterium lunula and hexagonal or elliptical crystals by Micrasterias thomasiana. High-resolution transmission electron microscopy (hrtem) has confirmed the single-crystal nature of the biological precipitates. The crystals all lie with their tabular faces perpendicular to the [001] zone axis and are comparable with the typical crystal habit of geological and synthetic barium sulphates, suggesting a limited degree of biological control over precipitation. M2+ (Ba2+ or Sr2+) : SO2-4 ion ratios in vivo and in vitro have been shown to affect the morphology of the crystals produced. For Closterium lunula an M2+: SO2-4 ion ratio of less than 1:1 produces rhombic crystals and an ion ratio of more than 10:1 produces hexagonal crystals. For Micrasterias thomasiana, an ion ratio of 0.01:1 produces hexagonal crystals; an ion ratio of 1:1 produces a mixture of hexagonal and elliptical crystals, and an ion ratio of more than 10:1 produces elliptical crystals. Crystal morphologies produced by desmids have been compared with those of synthetic crystals produced at similar ion ratios. The apparently limited extent of biological control and the importance of the ionic environment on the development of crystal morphology are discussed. It is proposed that desmid crystal morphology may provide a diagnostic for the local environment of crystal formation in the cell.
Combined inelastic neutron scattering and solid-state density functional theory study of dynamics of hydrogen atoms in muscovite 2M1

Abstract Inelastic neutron scattering (INS) was used to study dynamics of the hydrogen atoms in natural 2M1 muscovite in the 150-1200 cm-1 energy range. The resultant INS spectra are interpreted by means of solid-state density functional theory calculations covering both normal mode analysis and molecular dynamics. While signatures of the Al-O-H bending modes were found over the whole energy transfer range, the dominant contributions were observed between 800-1000 cm-1. The modes assigned to the in-plane movements of the respective hydrogen atoms are well defined and always appear at high energies. In contrast, the modes corresponding to the out-of-plane movements are spread over large energy transfer ranges, extending down to the region of external (lattice) modes. The positions of the high-energy modes contributing to the INS band at -907 cm-1 depend on the distance of respective hydrogen atoms to the nearest oxygen atom of the basal net and its polarity
Essential Oils of Rhizomes and Rootlets of Valeriana celtica L. ssp. norica Vierh. from Austria

Abstract Dried plants of Valeriana celtica L. ssp. norica Vierh. collected in Austria have been divided in two fractions, one containing the rootlets and the other containing rhizomes and rest of stems and leaves. The rootlets showed higher oil contents (2.5% in contrast to 0.75% of the rhizomes) and higher amounts of patchouli alcohol (15.1%) and of an unknown oxygenated sesquiterpene (13–2%) than the rhizomes. The rhizomes contained more aromadendrene (14.0% vs. 6.5% of the rootlets). Other main compounds were β-pinene, α-guaiene/seychellene, spathulenol and two other unknown compounds of MW-220. The Austrian oil of V. celtica ssp. norica differs compared to Italian leaf oil of V. celtica from the Aosta valley, especially in the content of isovaleric acid and patchouli alcohol.
Using Journal Articles to Teach Writing Skills for Laboratory Reports in General Chemistry

A strategy for helping students develop technical writing skills through laboratory report assignments is described. The students begin by examining a recent journal article, writing a citation for it, and listing the sections the article contains. Students are given guidelines for constructing one specific section and are assigned the task of writing or creating that section for a specific laboratory experiment they have completed. The process is repeated so that each laboratory report focuses on a different part of a journal article. This approach to laboratory reports gives students an introduction to techniques necessary for good technical writing, yet is simple enough for a general chemistry course. Because each laboratory report is just one section of a full, formal laboratory report, grading is structured and straightforward.
A Screen‐Printed, Amperometric, Biosensor Array for the Detection of Organophosphate Pesticides Based on Inhibition of Wild Type, and Mutant Acetylcholinesterases, from Drosophila melanogaster

Abstract Screen‐printed carbon electrodes (SPCEs) modified with cobalt phthalocyanine (CoPC) have been used as base transducers in the construction of amperometric pesticide biosensors. Six individual biosensors were fabricated by depositing wildtype (WT) acetylcholinesterase (AChE) from Drosophila melanogaster or one of five mutant forms (B02, B03, B04, B421, and B65) of this enzyme, onto the surfaces of CoPC‐SPCEs; these constituted the amperometric biosensor array. The enzyme converts acetylthiocholine into its electroactive product thiocholine, which is detected at only 0 V vs. Ag/AgCl at the CoPC‐SPCEs. The measurement step is performed using chronoamperometry. In the presence of an organophosphate (OP) pesticide, the enzyme is inhibited, which leads to a decrease in thiocholine production and a corresponding decrease in anodic current. This decrease is proportional to the logarithm of the pesticide concentration. Calibration studies were performed with the biosensor array using five OPs of interest to the food industry, namely omethoate, malaoxon, dichlorvos, chlorpyrifos‐methyl‐oxon, and pirimiphos‐methyl‐oxon. It was found that different inhibition patterns occurred for the five OPs indicating the possibility of identifying and quantifying these compounds in food samples. It should be added that there was no detrimental affect on the biosensor response from wheat or apple extracts.
Effect of Nano-Magnesium Hydride on the Thermal Decomposition Behaviors of RDX

In order to improve the detonation performance of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) explosive, addictives with high heat values were used, and magnesium hydride (MgH2) is one of the candidates. However, it is important to see whether MgH2 is a safe addictive. In this paper, the thermal and kinetic properties of RDX and mixture of RDX/MgH2 were investigated by differential scanning calorimeter (DSC) and accelerating rate calorimeter (ARC), respectively. The apparent activation energy (E) and frequency factor (A) of thermal explosion were calculated based on the data of DSC experiments using the Kissinger and Ozawa approaches. The results show that the addition of MgH2 decreases both E and A of RDX, which means that the mixture of RDX/MgH2 has a lower thermal stability than RDX, and the calculation results obtained from the ARC experiments data support this too. Besides, the most probable mechanism functions about the decomposition of RDX and RDX/MgH2 were given in this paper which confirmed the change of the decomposition mechanism.
Low-Temperature Processing of Wheat for Bioethanol Production: Part I. Studies on the Use of Commercial Enzymes1

The uncertainty of fossil fuel reserves, volatility of oil prices, and increasing release of carbon dioxide and other pollutants into the environment have led to a growing interest in the production of fuel ethanol. Research on bioethanol production has focused on all phases of the process, from raw materials to by-product recovery, and is directed toward improving the efficiency of fermentation and reducing the cost of ethanol production. However, there is still great scope for developing an efficient and inexpensive production process for bioethanol. This article describes a production process for bioethanol using wheat as a feedstock. This process was developed following analysis of mashing parameters such as wheat inclusion rate, pH, temperature, and exogenous enzyme choice. Further work showed that cooking the wheat was not required and that the process of backsetting benefited fermentation. These results have allowed the development of a proposed low-cost production process that will be of use in Northern Europe.
VISCOELASTIC BEHAVIOUR DURING THE GELATINIZATION OF STARCH II. EFFECTS OF EMULSIFIERS

The viscoelastic behaviour during the gelatinization of starch in the presence of emulsifiers was studied in oscillatory shear. Glycerol-monostearate and sodium stearoyl-lactylate delayed the viscoelustic changes during gelatinization in a way which was intetpreted as related to the granules being stiffer in presence of these emulsifiers. Sodium abdecyl sulphate caused a destabilization of the granules, resulting in the rheological changes occurring at lower temperatures. Emulsifiers increased the viscous part of the rheological response. In a wary-starch variety, where the amount of amylase is small, emulsifiers had only a small effect on gelatinization. It was concluded that the formation of an amylose-lipid complex was of importance if an emulsifier was to exert an effect.
Impactos da construção da usina hidrelétrica de Sobradinho no regime de vazões no Baixo São Francisco

A regularizacao das vazoes no baixo Rio Sao Francisco e atribuida as barragens construidas ao longo do seu curso. Neste artigo e avaliada a magnitude das alteracoes no regime de vazoes do rio, provocadas pela construcao do reservatorio de Sobradinho utilizando-se curvas de permanencia de cotas e vazoes como ferramenta de analise. O trecho estudado tem extensao de 197 km, desde a estacao de Piranhas,AL, ate a foz do rio no Oceano Atlântico. Foram utilizadas series historicas de cotas e vazoes de quatro estacoes fluviometricas que tiveram suas curvas-chave corrigidas com referencia de nivel IBGE. A construcao de sobradinho causou uma reducao percentual media de 6 a 12% nas cotas maiores (C5) e uma elevacao de 20 a 32% nas cotas menores (C95). Houve reducao de 9% na vazao maxima (Q5) e aumento de 27% na vazao minima (Q95). As vazoes Q5 e Q95 foram de 5.652 e de 1.231 m3 s-1 na estacao de Pao de Acucar para o periodo apos Sobradinho. Os resultados mostram que a regularizacao do regime de vazoes apos a construcao de Sobradinho minimizou os efeitos das grandes cheias nas regioes a jusante mas tambem vem afetando negativamente atividades tradicionais das populacoes ribeirinhas, como a pesca, navegacao e agricultura.
Polymeric Hydrophilic Hydrogels with Flexible Hydrophobic Chains. Control of the Hydration and Interactions with Water Molecules

Acrylic hydrogels based on 2-hydroxyethyl methacrylate, H, have been synthesized by copolymerization reaction of this monomer with 2-ethylhexyl acrylate, E, using AIBN as initiator. Reactivity ratios were estimated from copolymerization reactions carried out in solution and at low conversion, by using both linearization and nonlinearization methods. They were found to be rE = 0.29 and rH = 2.54. The swelling behavior of the hydrogels was studied by immersion of copolymer films prepared by bulk copolymerization, in water at different temperatures. Equilibrium water uptake was strongly dependent on composition and decreased with the E content in the copolymer. Fickian behavior was observed in all cases for reduced sorption coefficients lower than 0.4. The diffusion coefficient was found to decrease with increasing E content in the copolymer. A value of apparent activation energy for the diffusion process of 8.8 kJ/mol was obtained for poly(2-hydroxyethyl methacrylate); however, H/E copolymers did not obey t.
Measurement of acid–base properties on metal oxide surfaces in aqueous solution

A potentiometric acid–base titration method was used to investigate the surface properties of metal oxides in aqueous solution. The metal oxides used were SiO2, γ-Al2O3, ZrO2, TiO2, SiO2–Al2O3, SiO2–ZrO2 and TiO2–ZrO2. The amounts of protonated hydroxyl group [graphic omitted] M—OH+2 and of ionized hydroxyl group [graphic omitted] M—O– present were studied as a function of solution pH. The results are consistent with those obtained by a n-butylamine titration method or a gas adsorption method.
Manejo do etileno durante o armazenamento de ameixas 'Laetitia' em atmosfera controlada

The objective of this research was to evaluate the effects of treatment with 1-methylcyclopropene (1-MCP) and different ethylene concentrations in the storage room on f 'Laetitia' plums quality stored under controlled atmosphere. The treatments evaluated were 1-MCP application (1.0µL L-1) and ethylene (C2H4) in the concentrations <0. 04µL L-1, 1. 0µL L-1, and 10µL L-1 inside the CA storage (1.0kPa of O2+3.0kPa of CO2 / 0.5°C±0.1°C and 95±2% RH) of. Respiratory rates were lower in fruits treated with 1-MCP and stored at 10µL L-1 of C2H4. Fruits treated with 1-MCP showed the lowest ethylene production rates. At removal from CA storage, fruits treated with 1-MCP and stored at C2H4 concentration <0. 04µL L-1 showed higher flesh firmness and fruit compression resistance and lower flesh browning incidence. After shelf life, fruits treated with 1-MCP had the highest flesh firmness. Titratable acidity was higher in fruit treated with 1-MCP and left in CA storage with <0. 04µL L-1 C2H4 concentration. 1-MCP and ethylene absorption delay ripening and reduce flesh browning incidence in 'Laetitia' plums. The effects of 1-MCP persist during shelf life. However, even with the use of these technologies, flesh browning occurrence does not allow fruit storage for 60 days under de CA storage condition used.
Uma métrica gráfica para avaliação holística da verdura de reacções laboratoriais - "Estrela Verde"

A new semi-quantitative metrics, Green Star (GS), for evaluation of the global greenishness of chemical reactions used in teaching laboratories has been developed. Its aim is to help choosing the more acceptable reactions for implementing Green Chemistry (GC) and to identify suitable modifications of reaction protocols to improve the greenishness of chemistry. GS considers globally all the Twelve Principles of GC. To illustrate its construction, the tetraamminecopper(II) sulfate monohydrate laboratory synthesis, performed under several sets of conditions to pursue greenishness, is presented. A comparative study with other GC metrics showed the advantages of GS and that it accomplishes its purpose.