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.

Influence of substrate on the structure of predominantly anatase TiO2 films grown by reactive sputtering.

TiO2 films are grown on LaAlO3 (001), Si (100) and SiO2 substrates by reactive radio frequency sputtering. X-ray diffraction (XRD) pole figures revealed important characteristics about the texture and phase distribution on those films. Combined with spectroscopic ellipsometry, the pole figures allowed the analysis of the growth characteristics over the whole volume of the layers. Details in the microstructure of the films were probed using transmission electron spectroscopy. Anatase is the dominating phase in the films grown on all substrates. On TiO2/LaAlO3 fims, the mosaicity is very low, so that the pole figure closely resembles that of anatase monocrystals. Detailed inspection of XRD pole figures reveals a small amount of rutile in the TiO2/LaAlO3 films. For the growth of TiO2 onto SiO2, rutile and brookite phases are also detected. Transmission electron microscopy and XRD results show the formation of anatase {112} twins in films grown on the different substrates, suggesting that the anatase {112} twin mediates the growth of rutile and brookite phases. Optical results are in agreement with the XRD observations: the optical properties of TiO2/LaAlO3 films are similar to the ordinary values of bulk anatase crystals, indicating the orientation of the film in the [001] direction, whereas results for TiO2/SiO2 are compatible with lower crystalline ordering.

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%.

Structural characterization of the GSK-3beta active site using selective and non-selective ATP-mimetic inhibitors.

GSK-3beta is a regulatory serine/threonine kinase with a plethora of cellular targets. Consequently, selective small molecule inhibitors of GSK-3beta may have a variety of therapeutic uses including the treatment of neurodegenerative diseases, type II diabetes and cancer. In order to characterize the active site of GSK-3beta, we determined crystal structures of unphosphorylated GSK-3beta in complex with selective and non-selective ATP-mimetic inhibitors. Analysis of the inhibitors' interactions with GSK-3beta in the structures reveals how the enzyme can accommodate a number of diverse molecular scaffolds. In addition, a conserved water molecule near Thr138 is identified that can serve a functional role in inhibitor binding. Finally, a comparison of the interactions made by selective and non-selective inhibitors highlights residues on the edge of the ATP binding-site that can be used to obtain inhibitor selectivity. Information gained from these structures provides a promising route for the design of second-generation GSK-3beta inhibitors.

Basic fibroblast growth factor stimulates hepatocyte growth factor/scatter factor secretion by human mesenchymal cells.

Basic fibroblast growth factor (bFGF) together with other pleiotropic factors plays an important role in many complex physiological processes such as embryonic development, angiogenesis, and wound repair. Among these factors, hepatocyte growth factor/scatter factor (HGF/SF) which is secreted by cells of mesodermal origin exerts its mito- and motogenic activities on cells of epithelial and endothelial origin. Knowledge of the regulatory mechanisms of HGF/SF may contribute to the understanding of its role in physio-pathological processes. We observed that the secretion of HGF/SF by MRC-5 cells and by other fibroblast-derived cell cultures in conditioned media was enhanced by exposure to bFGF. HGF/SF was measured by the scatter assay, a bioassay for cell motility, and was further characterized by Western blot analysis with anti-HGF/SF antibodies. Exposure of MRC-5 cultures to 10 ng/ml of bFGF resulted already 6 h posttreatment in a threefold higher amount of scatter factor secreted into the medium as compared to untreated cultures. HGF/SF secretion was sustained after bFGF treatment for the following 72 h when increased amounts of HGF/SF were detected both in conditioned media as well as associated to the extracellular matrix. The secretion of HGF/SF in cell supernatants increased dose dependently upon treatment with bFGF starting from basal levels of 6 U/ml and reaching 27 U/ml at 30 ng/ml bFGF, plateauing thereafter. Upregulation of HGF/SF by IL-1, already described by others, was confirmed in this study. Based on our findings an articulated interaction can be speculated for bFGF, HGF/SF, and IL-1, e.g., in tissue regeneration during inflammatory processes or in wound healing.

Suramin modulates cellular levels of hepatocyte growth factor receptor by inducing shedding of a soluble form.

Several growth factor receptors undergo shedding from the cell surface as a result of limited proteolysis via mechanisms that are at present poorly understood. By Western blotting of the conditioned media and cell lysates of several cell lines expressing the hepatocyte growth factor receptor, we found that suramin, a pharmacological agent that inhibits the activity of many growth factors, was able to induce shedding of this receptor. Increased levels of soluble hepatocyte growth factor receptor were observed in the conditioned media of GTL-16, a cell line over-expressing the receptor, as early as ten minutes after initial exposure to the agent, and incubation of this line with 300 microM suramin caused a 50% reduction in cell-associated levels of receptor after 6 hours. Although protein kinase C activation by treatment of cells with phorbol esters has previously been found to stimulate shedding of the hepatocyte growth factor receptor, this hitherto undescribed activity of suramin was not affected by protein kinase C inhibitors. Since shedding represents a possible means of down-modulation of receptor activity, suramin may inhibit the hepatocyte growth factor ligand/receptor system, not only by abrogation of hepatocyte growth factor binding to intact receptor, but also by induction of receptor shedding.

D-amino acid scan of endothelin: importance of amino acids adjacent to cysteinyl residues in isomeric selectivity.

A systematic approach to map the functionally important determinants of endothelin-1 (ET-1) by a D-amino acid scan is described. Correct orientation of the amino acid side chains was generally of paramount importance both for binding at the ETA receptor and for contracting activity. This was particularly valid for positions 2, 8, 14, 16-21 (the four Cys residues were kept unaltered). Nevertheless, increment of binding affinity was observed by inversion of configuration at positions 6, 7, 9 and 10. In addition, [D-Lys9]ET was an agonist about four times more potent than the natural compound. Usually both 1,4- and 1,3-isomers (corresponding, respectively, to the correct and misfolded disulfide bridges of ET) were obtained, and usually the isomer formed in larger amount had the higher HPLC retention time and the higher biological activity. However, four out of seventeen single-point D-amino acid analogues could be isolated only in one isomeric form. In three cases (D-Ser2, D-Ser4, D-Val12), the inverted amino acid was adjacent to a Cys residue, and in one case (D-Lys9) it was one amino acid apart, thus suggesting a possible effect of the bridged cysteinyl residues in isomeric selectivity.

Endothelin-1-selective binding sites are downregulated by transforming growth factor-beta and upregulated by basic fibroblast growth factor in a vascular smooth muscle-derived cell line.

Endothelins (ETs) elicit in vivo and in vitro a potent vasoconstrictor activity after binding to high-affinity receptors on vascular smooth muscle cells (VSMC). A617 cells, a VSM-derived cell line, were used as an in vitro model system to study selected growth factors and cytokines involved in proliferative and/or inflammatory diseases of the vessel wall as possible regulators of the high-affinity binding capacity of ET-1 to the cells. Radioligand studies characterized the binding of ET-1 to the isopeptide selective ETA receptor subtype on A617 cells as a time- and temperature-dependent saturable process (Kd = 0.13 +/- 0.04 nM, Bmax = 49 +/- 7 fmol/10(6) cells). Pretreatment of A617 cells with basic fibroblast growth factor (bFGF), a mitogenic agent for vascular cells, resulted in a time- and dose-dependent increase in ET-1 binding capacity, whereas preexposure to transforming growth factor-beta (TGF-beta) induced a reduction of the Bmax for ET-1. Platelet-derived growth factor (PDGF), interleukin-6 (IL-6), tumor necrosis factor-alpha, and fetal bovine serum (FBS) pretreatments did not affect consequent ET-1 binding to A617 cells.

Alanine scan of endothelin: importance of aromatic residues.

A systematic approach to map the functional important determinants of endothelin-1 (ET) by an alanine scan is described. Studies on the in vitro receptor binding affinity and on the agonist contracting activity defined that residues Asp8, Tyr13, Phe14, Leu17, and Trp21 were of major biological significance. A striking observation was that four out of these five sites were hydrophobic amino acids. Ala analogues of the aromatic residues at position 13, 14, and 21 displayed sharply reduced receptor binding affinity (< 2% of ET) and can be considered important for receptor contact. Ala analogues of Asp8 and Leu17 lost most (> 90%) of the agonist activity but retained a receptor affinity nearly equivalent to ET and can be considered to be important for signal transduction. Three other positions, Val12, Asp18, and Ile20 (which are adjacent to the biologically important sites of Tyr13, Leu17, and Trp21), resulted as partially tolerant to Ala substitution, retaining 14-50% of the potency of ET. Ala analogues of the Et isomeric disulfide arrangement (Cys1,11 and Cys3,15) were always less active than the corresponding analogues with the native disulfide pairings (Cys1,15 and Cys3,11).

Morphology and nuclear contents in IVF embryos.

Human pre-embryos, at 2-8 cells, with different morphology have been examined for chromosome constitution. Concerning the informative pre-embryos (23/65), 11 showed a normal karyotype and in 12 an abnormal karyotype was observed; there was not a complete correspondence between pronucleation and chromosome set. Also in the interphasic pre-embryos the presence of chromatin masses at different sizes was revealed. The observation of polyploid and/or polynucleated blastomeres can suggest a failure of synchronization between cytoplasmatic and nuclear division. Mosaicism, polyploidy and polynucleation are phenomena that could be caused by in vitro culture conditions or dependent upon the genetic anomaly of the zygote.

Lack of immunization after intraperitoneal insemination of spermatozoa.

Twenty infertile patients with normal tubal patency were inseminated intraperitoneally (11 once, seven twice, and two three times) with spermatozoa (mean 14 x 10(6), range 0.6-48 x 10(6)) prepared by the standard swim-up technique. The occurrence of immunization to spermatozoa was looked for by the Gelatin Agglutination Test (GAT) and Tray Agglutination Test (TAT). Both tests gave negative results for all the controls (10 pregnant and 10 puerperal women). Antisperm antibodies were measured in the serum before, 30 d and 4-7 months after Intraperitoneal Insemination (IPI). The last check was done for only 14 patients, since six became pregnant as a consequence of the first treatment. Of the 14 patients studied after 4-7 months, seven had two, and two had three IPI. In the group of inseminated patients, 18 women with no basal sperm antibody did not show evidence of antibody formation after the treatment and it was not increased after insemination in the two patients who already had low antibody titre (1/32). In conclusion, despite the large number of spermatozoa inseminated and even after several IPI attempts, there was no evidence of de novo production of or increase in already present anti-sperm antibodies according to the methods used for the detection of ASA in this study.

Stabilization of recombinant human basic fibroblast growth factor by chemical modifications of cysteine residues.

The production of recombinant human basic fibroblast growth factor (rhbFGF) in Escherichia coli cells yielded active forms of this polypeptide which, however, displayed a high degree of instability towards oxidative processes. Biochemical studies in our laboratory and those of others indicated that the reactivity of the four cysteine residues was the main cause of the observed instability. Several attempts to obtain more stable derivatives of rhbFGF were carried out by modification of the sulfhydryl groups. Among these, treatment of rhbFGF with iodoacetic acid led to the isolation of a partially carboxymethylated form (Cm-FGF). Peptide mapping analysis of the modified protein showed that two cysteines (78 and 96) were blocked by a carboxymethyl group. The remaining cysteines (34 and 101) were not modified under the conditions used and were found to be in the reduced form. Cm-FGF and unmodified rhbFGF showed similar affinity both for heparin and for high-affinity receptors. Cm-FGF was more stable than the unmodified molecule as measured by HPLC and SDS/PAGE analysis. Interestingly, Cm-FGF was more active than unmodified rhbFGF in stimulating proliferation of endothelial cells and DNA synthesis in 3T3 fibroblasts. This new derivative could represent a desirable complementation to rhbFGF for the development of more stable pharmaceutical formulations in wound healing applications.

Pregnancy after direct intraperitoneal insemination of spermatozoa from a man with severe infertility, after unsuccessful application of other methods of assisted fertilization.

Direct intraperitoneal insemination (DIPI) is one of the least invasive strategies of assisted reproduction. Unexplained infertility and male sub-fertility are the major indications for DIPI. It is otherwise well known that assisted procreation gives poor results in severe male infertility. This is a report of a pregnancy that occurred as a result of a direct intraperitoneal insemination of prepared spermatozoa characterized by a particularly severe astheno-teratozoospermia in a couple unsuccessfully treated with other, more invasive methods of assisted fertilization.

IVF: induction of ovulation in poor responders.

All IVF programs have a consistent rate of failure in inducing ovulations. Pharmacological induction of ovulation is otherwise crucial for an IVF program because of the need for more than one ovum. Since it is well known that the best candidates for HMG treatment are hypogonadotropic women a short reversible hypogonadotropic state was induced in IVF patients by LH-RH agonist (Buserelin). Superovulation was then achieved with very high initial doses of FSH (Metrodin) in order to maximize the ovarian response. This technique used in 116 IVF women induced a satisfactory follicle growth even in 70% of the patients already poorly responsive to HMG stimulation.

Ovarian stimulation of IVF patients: effects of the reversible hypogonadotrophic state induced by GnRH agonist.

Multiple ovulation was induced in 122 hypogonadotrophic IVF patients with large doses of HMG. The hypogonadotrophic state, short and reversible, was obtained by nasal administration of a GnRH agonist (200 micrograms, five times per day). In the 97 induced cycles, a mean of 9.1 follicles was recorded. A comparison of the results obtained for 36 patients who had already been treated with clomiphene and HMG showed both significantly more follicles per cycle (8.5 versus 3.0) and an increase in oocytes retrieved (6.7 versus 1.3) when treated with the agonist and HMG. In addition 11 of 18 already poorly responsive patients had normal responses. The luteal phase was supported by either HCG or progesterone injection. Plasma progesterone profiles were satisfactory and, as expected, the highest progesterone concentrations were associated with HCG treatment.