The role of pressure-induced stacking faults on the magnetic properties of gadolinium

Experimental data show that under pressure, Gd goes through a series of structural transitions hcp to Sm-type (close-packed rhombohedral) to dhcp that is accompanied by a gradual decrease of the Curie temperature and magnetization till the collapse of a finite magnetization close to the dhcp structure. We explore theoretically the pressure-induced changes of the magnetic properties, by describing these structural transitions as the formation of fcc stackings faults. Using this approach, we are able to describe correctly the variation of the Curie temperature with pressure, in contrast to a static structural model using the hcp structure.Comment: Preprint (no peer-reviewed

Influência do número de camadas na propriedade mecânica de espécimes fabricados com atadura gessada usados para confeccionar splints ortopédicos

OBJECTIVE: To evaluate the effects of varying numbers of layers of plaster of Paris bandages on the mechanical properties of specimens used on the construction of orthopedic splints. METHODS: Rectangular plate-shaped and cylinder-shaped specimens were constructed and assigned to two groups simulating plaster slabs and cast and further divided into six subgroups according to the number of layers used: 3, 6, 8, 10, 12 and 14 layers. The specimens were subjected to either a three-point bending test (plates/slab) or compressive strength test (cylinders/cast). The following mechanical properties were evaluated: maximum load, elastic limit load and stiffness. Specimen weight was also calculated. Data was analyzed using Kruskal-Wallis and the least significant difference (LSD) tests. RESULTS: Pairwise comparisons of the subgroups 10x12 and 10x14 revealed significant differences for all mechanical properties (p<0.05). The results of this study suggest that when the goal is to construct appliances with high mechanical strength, regardless of weight, such as serial plaster slabs splints for stimulating tissue growth through the application of gradual load, splints made with plaster of Paris bandages with 12 or 14 layers should be preferred. For orthotic devices such as positioning orthotics, the use of 10 layers plaster bandages slab splints is advisable as they were found to have better correlation between mechanical strength and weight in comparison to those made wtih 6 or 8 layers. CONCLUSION: Based on the findings of this study, we suggest the use of 10 layers of plaster of Paris for the construction of orthopedic splints.OBJETIVO: Avaliar as propriedades mecânicas de amostras fabricadas a partir de ataduras de gesso que são utilizadas em órteses ortopédicas e que variam quanto ao número de camadas. MÉTODOS: Foram confeccionados espécimes em forma de placa retangular e em forma cilíndrica, divididos em dois grupos que simulavam splint e gesso circular, os quais foram divididos em seis subgrupos de acordo com o número de camadas utilizadas, ou seja, três, seis, oito, dez, 12 e 14 camadas. Os espécimes foram submetidos a um teste de inclinação de três pontos (placas/splint) ou teste de resistência à compressão (cilindros/gesso circular). As seguintes propriedades mecânicas foram avaliadas: carga máxima e carga no limite de elasticidade e rigidez. O peso da amostra foi calculado. Os dados foram analisados estatisticamente pelos testes de Kruskal-Wallis e diferença mínima significativa (DMS). Comparações pareadas entre os subgrupos 10x12 e 10x14 revelaram diferenças significativas para todas as propriedades mecânicas (p<0,05). RESULTADOS: Os resultados sugerem que, quando o objetivo é construir aparelhos com alta resistência mecânica, independente do peso, tais como órteses seriadas de posicionamento para simular força gradual aplicada no tecido para a melhoria da amplitude de movimento, talas de 12 ou 14 camadas devem ser preferidas. Para os aparelhos ortopédicos que irão ser submetidos a esforços de baixa intensidade, aconselha-se a utilização de dez camadas para as órteses, porque houve uma melhor correlação entre a resistência mecânica e peso para as amostras fabricadas com dez camadas de atadura gessada comparadas com aquelas confeccionadas com seis ou oito camadas. CONCLUSÂO: Baseado nos achados deste estudo, sugere-se a utilização de dez camadas na confecção de órteses ortopédicas

Copper catalyzed cross-coupling reactions of diaryl ditellurides with potassium aryltrifluoroborate salts

We present here results of the cross-coupling reaction of diaryl ditellurides with potassium aryltrifluoroborate salts using a catalytic amount of Cu(OAc)2 and bypiridine in DMSO/H2O under air atmosphere. This cross-coupling reaction is general and was performed with diaryl ditellurides and potassium aryltrifluoroborate salts bearing electron-withdrawing, electron-donating and neutral substituents, affording the corresponding unsymmetrical diaryl tellurides in good to excellent yields.Apresentamos aqui resultados das reações de acoplamento de diteluretos de diarila com sais de ariltrifluoroborato de potássio, usando quantidades catalíticas de Cu(OAc)2 e bipiridina, em uma mistura de DMSO/H2O, sob ar atmosférico. Estas reações de acoplamento são gerais e são realizadas com diteluretos de diarila e sais de ariltrifluoroborato de potássio contendo substituintes neutros, retiradores e doadores de elétrons, fornecendo os correspondentes teluretos de diarila não simétricos em rendimentos de bons a excelentes.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) (Grants 07/56659-0 and 07/59404-2

Potassium trifluoro­[(Z)-3-methoxy­prop-1-en­yl]borate

In the title salt, K+·C4H7BF3O−, the K atom is surrounded by six anions making close contacts through seven F [K⋯F = 2.779 (1)–3.048 (1) Å] and two O [K⋯O = 2.953 (2) and 3.127 (2) Å] atoms in a trivacant fac-vIC-9 icosa­hedral coordination geometry

Exploiting the Redox Activity of MIL-100(Fe) Carrier Enables Prolonged Carvacrol Antimicrobial Activity

The design of efficient food contact materials that maintain optimal levels of food safety is of paramount relevance to reduce the increasing number of foodborne illnesses. In this work, we develop a smart composite metal-organic framework (MOF)-based material that fosters a unique prolonged antibacterial activity. The composite is obtained by entrapping a natural food preserving molecule, carvacrol, into a mesoporous MIL-100(Fe) material following a direct and biocompatible impregnation method, and obtaining particularly high payloads. By exploiting the intrinsic redox nature of the MIL-100(Fe) material, it is possible to achieve a prolonged activity against Escherichia coli and Listeria innocua due to a triggered two-step carvacrol release from films containing the carvacrol@MOF composite. Essentially, it was discovered that based on the underlying chemical interaction between MIL-100(Fe) and carvacrol, it is possible to undergo a reversible charge-transfer process between the metallic MOF counterpart and carvacrol upon certain chemical stimuli. During this process, the preferred carvacrol binding site was monitored by infrared, Mössbauer, and electron paramagnetic resonance spectroscopies, and the results are supported by theoretical calculations

Thermal stability of plasma-nitrided aluminum oxide films on Si

The effect of post-deposition rapid thermal annealing in vacuum and in dry O2 on the stability of remote plasma-assisted nitrided aluminum oxide films on silicon is investigated. The areal densities of Al, O, N, and Si were determined by nuclear reaction analysis and their concentration versus depth distributions by narrow nuclear reaction resonance profiling, with subnanometric depth resolution. Annealing in both vacuum and O2 atmospheres produced partial loss of N from the near-surface regions of the films and its transport into near-interface regions of the Si substrate. Oxygen from the gas phase was incorporated in the AlON films in exchange for O and N previously existing therein, as well as in the near-interface regions of the Si substrate, leading to oxynitridation of the substrate. Al and Si remained essentially immobile under rapid thermal processing, confirming that the presence of nitrogen improves the thermal stability characteristics of the AlON/ Si structures in comparison with non-nitrided Al2O3 /Si

DETECÇÃO MOLECULAR DE HEMOPLASMAS EM BOVINOS E OVINOS EM SISTEMA DE CRIAÇÃO CONSORCIADA DO NORDESTE DO BRASIL – DADOS PRELIMINARES

Micoplasmas hemotrópicos (hemoplasmas) são microrganismos gram-negativos e que ficam aderidos aos eritrócitos de diversas espécies de mamíferos. Em pequenos ruminantes, Mycoplasma ovis, e em bovinos, Mycoplasma wenyonii e ‘Candidatus Mycoplasma haemobos’ são as espécies já descritas. Nessas espécies animais a transmissão dos hemoplasmas pode estar relacionada à infestação por carrapatos ou picadas de moscas hematófagas. A infecção por hemoplasmas pode causar anemia hemolítica aguda, porém os sinais clínicos diferem de acordo com a espécie de hemoplasma envolvido, do animal parasitado, idade e sistema de produção em que é criado. Embora a hemoplasmose tenha sido relatada causando perdas econômicas significativas na criação de ruminantes em todo o mundo, dados de hemoplasmas em sistema de criação consorciada são inexistentes. Assim, o objetivo deste estudo é determinar a prevalência de hemoplasmas em bovinos e pequenos ruminantes provenientes de um sistema de criação consorciada no nordeste do Brasil. Até o momento, um total de 15 amostras (10 ovinos e cinco bovinos) foram triadas utilizando um protocolo de PCR para o gene 16S rRNA de hemoplasmas. As amostras positivas foram submetidas a uma PCR para o gene 23S rRNA de hemoplasmas. Todas as amostras foram positivas para o gene endógeno gliceraldeído 3-fosfato desidrogenase (gapdh). Todos as amostras de ovinos foram negativas para hemoplasmas. Três de cinco (60%) bovinos foram positivos para Mycoplasma spp. O estudo envolverá a triagem das amostras por PCR em tempo real

Potassium trifluoro­[(Z)-3-(oxan-2-yl­oxy)prop-1-en-1-yl]borate monohydrate

The title compound, K+·C8H13BF3O2 −·H2O, which was obtained from the reaction of a modified form of Z-vinylic telluride via a transmetalation reaction with n-BuLi, crystallizes as K+ and C8H13BF3O2 − ions along with a water mol­ecule. The K+ cation is surrounded by four anions, making close contacts with six F atoms at 2.659 (3)–2.906 (3) Å and with two O atoms at 2.806 (3) and 2.921 (3) Å in a distorted bicapped trigonal-prismatic geometry

Seagrasses benefit from mild anthropogenic nutrient additions

Seagrasses are declining globally, in large part due to increased anthropogenic coastal nutrient loads that enhance smothering by macroalgae, attenuate light, and are toxic when in excessive concentrations of inorganic nitrogen and phosphorus. However, as sanitation is improved many seagrass meadows have been observed to recover, with a few studies suggesting that they may even benefit from mild anthropogenic nutrient additions. Monitoring seagrass demography and health has faced difficulties in establishing the adequate variables and metrics. Such uncertainty in the methods has caused uncertainty of the significance of results presented and compromised extrapolations to other seasons, areas, or species. One solution has come from within the plant self-thinning theories. During the 1980s, an interspecific boundary line (IBL) was determined as the upper limit of the combination of plant density and above-ground biomass for any stand on Earth, setting their maximum possible efficiency in space occupation. Recently, two meta-analyses to determine specific IBLs for algae and for seagrasses have been performed. The recently updated seagrass dataset comprises 5,052 observations from 78 studies on 18 species. These IBLs opened new perspectives for monitoring: the observed distance of a stand to the respective IBL (i.e., each stand's relative efficiency of space occupation) was demonstrated to be a valuable indicator of a population's health. Thus, this metric can be used to determine the impact of nutrients and pollutants on algae and seagrass populations. Furthermore, because the IBLs are common to all species, they may be used to compare all species from any location worldwide. This novel approach showed that Halodule wrightii, Halodule beaudettei, Halophila baillonii, Zostera marina, and Zostera noltei meadows benefit from anthropogenic additions of nitrogen and phosphorus, as long as these additions are moderate. In fact, the healthier Z. noltei meadows in Portugal (and among the healthiest meadows worldwide) were the ones exposed to effluents from wastewater treatment plants (WWTP) and a food factory. We conclude that those effluents are providing water with enough quality and that their optimal management should coordinate the technological solutions of the WWTP with the natural potential of seagrass meadows as water purifiers and biomass producers.info:eu-repo/semantics/publishedVersio

FAUNA IXODÍDEA DE ANIMAIS SILVESTRES DO ESTADO DO PARANÁ, BRASIL – DADOS PRELIMINARES

Os carrapatos são conhecidos por parasitar uma variedade de hospedeiros domésticos e silvestres, incluindo mamíferos, aves, répteis e anfíbios. Além disso, muitos animais silvestres participam do ciclo epidemiológico de doenças transmitidas por carrapatos. Nesse sentido, o objetivo desse estudo foi identificar as espécies de carrapatos parasitando animais silvestres atendidos no Hospital Veterinário, Universidade Federal do paraná, Curitiba, Brasil. Os carrapatos foram coletados de 28 animais silvestres: uma anta (Tapirus terrestres), um cervídeo (Mazama sp.), um javali (Sus scrofa), dois bugios (Alouatta guariba), duas capivaras (Hydrochoerus hydrochaeris), 9 ouriços-cacheiros (Sphiggurus villosus), quatro tamanduás-mirins (Tamandua tetradactyla), seis gambás (Didelphis spp.), um gato-mourisco (Herpailurus yagouaroundi) e um teiú (Tupinambis sp.). Ao todo, foram coletados 115 carrapatos (65 machos, 33 fêmeas e 17 ninfas): Amblyomma aureolatum (1M, 3F, 2N) em dois bugios, um gambá e um gato-mourisco; Amblyomma calcaratum (8M, 2F) em 4 tamanduás-mirins; Amblyomma dubitatum (6M, 1F, 7N) em duas capivaras e um gambá; Amblyomma fuscum (3F) em um teiú; Amblyomma longirostre (28M, 8F, 4N) e Amblyomma parkeri (4M, 3F, 3N) em nove ouriços-cacheiros; Amblyomma ovale (1F) em um javali; Amblyomma sculptum (6M, 7F) em uma anta e um javali; Haemaphysalis juxtakochi (1N) em um cervídeo e Ixodes loricatus (12M, 5F) em cinco gambás. Estudos são necessários para melhor avaliar o papel dessas espécies na epidemiologia das doenças transmitidas por carrapatos