Vibrational properties of metastable orthorhombic Bi2Se3.

Chalcogenide materials are being considered as some of the most promising systems for energy harvesting and energy conversion. Among them, the orthorhombic family of compounds X2Y3 (with X = Bi, Sb and Y = S, Se) has attracted special attention due to its interesting atomic structure and thermoelectric and optical properties. While Bi2S3 and Sb2Se3 have already been applied to solar cells, practical application of the new metastable Bi2Se3 is still a challenge due to the lack of data and knowledge on its properties. Here, the vibrational and structural properties of the orthorhombic metastable phase of Bi2Se3 are investigated by using Raman spectroscopy and ab initio calculations. We perform Raman spectroscopy measurements along with in situ thermal treatment on samples grown by electrochemical deposition. We show that by increasing the temperature an improved crystallization occurs in the orthorhombic structure, followed by recrystallization to the usual rhombohedral phase. Our results point out specific Raman modes of the orthorhombic phase. First principles computational results based on the density functional theory support the experimental data and describe three singlet Raman active vibrational modes, such as B(2)3g, B(2)2g and A(6)g.

Resistive Switching in Electrodeposited Prussian Blue Layers.

Prussian blue (PB) layers were electrodeposited for the fabrication of Au/PB/Ag stacks to study the resistive switching effect. The PB layers were characterized by different techniques to prove the homogeneity, composition, and structure. Electrical measurements confirmed the bipolar switching behavior with at least 3 orders of magnitude in current and the effect persisting for the 200 cycles tested. The low resistance state follows the ohmic conduction with an activation energy of 0.2 eV.

Descarte de medicamentos: programas de recolhimento e novos desafios / Disposal of medicines: gathering programs and new challenges

O descarte de medicamento feito pela população é um tema que vem sendo cada vez mais discutido, Há uma crescente preocupação, pois a grande maioria da população não tem o conhecimento das consequências ambientais e nem das consequências à saúde pública que o descarte incorreto de medicamentos pode causar, Surgem ao redor do país, algumas iniciativas privativas e isoladas apresentando soluções à problemática, oferecendo à população estrutura para o descarte correto e informação sobre o tema, Por ainda não haver uma legislação nacional efetiva sobre o assunto, os estados lançam leis, regulamentando a problemática em seus territórios, No Ceará, foi sancionada em 2012 a lei no 15.192, obrigando às farmácias, drogarias e distribuidoras de medicamentos a recolherem os medicamentos da população, porém, devido à realidade local, não está sendo totalmente cumprida, Com a intensificação de discussões sobre as iniciativas particulares e as legislações locais, com o envolvimento de vários setores da sociedade e com a troca de experiências de programas em funcionamento, torna-se possível impulsionar projetos em locais onde a população ainda não tem oportunidade de dar a destinação correta aos medicamentos em desuso, Esse artigo traz à discussão a ocorrência de resíduos de medicamentos no meio ambiente, aspectos relacionados aos avanços na legislação brasileira quanto ao manejo de resíduos de medicamentos, às propostas de implantação de programas de recolhimento de medicamentos no país e alguns de seus desafios...

Drug disposal by the population is an important issue that has been widely discussed. There is a growing concern, because the vast majority of the population has no awareness on the environmental and public health consequences related to incorrect disposal of drugs. Some isolated initiatives arise around the country presenting solutions to the problem, and offering structure and information for proper disposal. There is still no effective national legislation in Brazil on the subject hence states launch laws regulating the problem in their own territory. In the state of Ceará the law 15192 was enacted in 2012 forcing pharmacies, drugstores and drug distributors to collect the population’s disposed drug, but due to local conditions, has not yet been fully met. With the intensification of discussions about particular initiatives and local laws, with the involvement of various segments of society and the exchange of experiences of running programs, it is possible to boost projects in areas where the population has no opportunity to give the correct destination for unused medicines. This article brings to the discussion the occurrence of drug waste in the environment, issues related to advances in Brazilian legislation regarding management of drug waste, proposals for implantation of drug collecting programs in the country and some of its challenges...

Description of evandromyia spelunca, a new phlebotomine species of the cortelezzii complex, from a cave in Minas Gerais State, Brazil (Diptera: Psychodidae: Phlebotominae).

BACKGROUND: The cave fauna of the Brazil is poorly documented, and among the insects those live or frequent caves and their adjacent environments phlebotomine sand flies call for special attention because several species are vectors of pathogens among vertebrates hosts. A new species of sand fly from Minas Gerais is described based in females and males collected in a cave of the municipality of Lassance. RESULTS: The morphological characters of the new species permit to include in the Evandromyia genus, cortelezzii complex. This complex consists of three species: Evandromyia corumbaensis (Galati, Nunes, Oshiro & Rego, 1989), Evandromyia cortelezzii (Brethes, 1923) and Evandromyia sallesi (Galvao & Coutinho, 1940). CONCLUSIONS: The new species can be separate from the others of the cortelezzii complex through morphological characters of the male terminalia and female spermathecae.

Development and validation of a stability-indicative agar diffusion assay to determine the potency of linezolid in tablets in the presence of photodegradation products.

Linezolid (LNZ) is one of the first commercially available (and most widely used) oxazolidinone antibiotics. This study describes the development and validation of a microbiological assay, applying the cylinder-plate method, for the determination of the antibiotic linezolid, as well as the evaluation of the ability of the method in determining the stability of linezolid in tablets. The validation method yielded good results and included linearity, precision, accuracy, robustness and selectivity. The assay is based on the inhibitory effect of LNZ upon the strain of Bacillus subtilis ATCC 9372 used as the test microorganism. The results of the assay were treated statistically by analysis of variance (ANOVA) and were found to be linear (r(2)=0.9998) in the range of 20-80 microg mL(-1), precise (inter-assay: R.S.D.=0.61) and accurate (R.S.D.=1.7). The method developed and validated proved to be indicative of stability and capable of determining the decay of linezolid in the presence of photodegradation products. Comparison of bioassay and liquid chromatography by ANOVA showed no significant difference between methodologies. The results demonstrated the validity of the proposed bioassay, which is a simple and useful alternative methodology for LNZ determination in routine quality control.

Determination of gatifloxacin in bulk and tablet preparations by high-performance liquid chromatography.

A sensitive, precise, and specific high-performance liquid chromatographic (HPLC) method was developed for the assay of gatifloxacin (GATX) in raw material and tablets. The method validation parameters yielded good results and included the range, linearity, precision, accuracy, specificity, and recovery. It was also found that the excipients in the commercial tablet preparation did not interfere with the assay. The HPLC separation was carried out by reversed-phase chromatography on a C18 absorbosphere column (250 x 4.6 mm id, 5 microm particle size) with a mobile phase composed of acetic acid 5%-acetonitrile-methanol (70 + 15 + 15, v/v/v) pumped isocratically at a flow rate of 1.0 mL/min. The effluent was monitored at 287 nm. The calibration graph for GATX was linear from 4.0 to 14.0 microg/mL. The interday and intraday precisions (relative standard deviation) were less than 1.05%.