Mineralogical and microthermometric studies and structural aspects of imperial topaz mineralization in Antonio Pereira, Ouro Preto District (Minas Gerais) - Brazil

The occurrences of imperial topaz in the Antonio Pereira mine, Ouro Preto, Minas Gerais, are associated with the metamorphic carbonate rocks of the Minas Supergroup. The crystals have densities varying from 3.46 to 3.58. The parameters of the unitary cells obtained were: 4.658 to 4.663 angstrom (ao), 8.823 to 8.832 angstrom (b(o)), 8.382 to 8.389 angstrom (c(o)), and 344.65 to 345.46 angstrom 3 (V). The refraction indices presented the following variations: 1.622 to 1.630 (nX), 1.624 to 1.632 (nY), 1.633 to 1.640 (nZ), and 0.008 to 0.011 (B). These properties are coherent with the low fluorine contents obtained (16,48%/17,05wt%). Infrared spectroscopy and microthermometry showed that the fluid inclusions, which represent the mineralizing fluids, are formed by H(2)O (with Ca(2+), Mg(2+) and Na(+)), and CO(2) +/- CH(4). The minimal trapping T-P conditions of 290/320 degrees C and 2,349/2,497bar were obtained for the primary fluid inclusions. The pseudo-secondary fluid inclusions were trapped at conditions of lower temperatures and variable pressures, during the deformation process under local alternating states of stress. The microthermometric studies, the structural analysis and the fluorine contents suggest that the mineralized veins were formed from hydrothermal fluids originated during the Brasiliano tectono-metamorphic event.

Identification of lift-off mechanism failure for salt drill-in drilling fluid containing polymer filter cake through adsorption/desorption studies

Drilling fluid`s contact with the productive zone of horizontal or complex wells can reduce well productivity by fluid invasion in the borehole wall. Salted drilling drill-in fluid containing polymers has often been applied in horizontal or complex petroleum wells in the poorly consolidated sandstone reservoirs of the Campos basin, Rio de Janeiro, Brazil. This fluid usually consists of natural polymers such as starch and xanthan gum, which are deposited as a filter cake on the wellbore wall during the drilling. Therefore, the identification of a lift-off mechanism failure, which can be detachment or blistering and pinholing, will enable formulation improvements. increasing the chances of success during filter cake removal in open hole operations. Likewise, knowledge of drill-in drilling fluid adsorption/desorption onto sand can help understand the filter cake-rock adhesion mechanism and consequently filter cake lift-off mechanism failures. The present study aimed to identify the lift-off failure mechanism for this type of fluid filter cake studying adsorption/desorption onto SiO(2) using solutions of natural polymers, lubricants, besides the fluid itself. Ellipsometry was employed to measure this process. The adsorption/desorption studies showed that the adsorbed layer of drilling fluid onto the walls of the rock pores is made up of clusters of polymers, linked by hydrogen bonds, which results in a force of lower cohesion compared to the electrostatic interaction between silica and polymers. Consequently, it was found that the most probable filter cake failure mechanism is rupture (blistering and pinholing), which results in the formation of ducts within the filter cake. (C) 2009 Elsevier B.V. All rights reserved.

Nonlinear diffraction of light beams propagating in photorefractive media with embedded reflecting wire

The theory of nonlinear diffraction of intensive light beams propagating through photorefractive media is developed. Diffraction occurs on a reflecting wire embedded in the nonlinear medium at a relatively small angle with respect to the direction of the beam propagation. It is shown that this process is analogous to the generation of waves by a flow of a superfluid past an obstacle. The ""equation of state"" of such a superfluid is determined by the nonlinear properties of the medium. On the basis of this hydrodynamic analogy, the notion of the ""Mach number"" is introduced where the transverse component of the wave vector plays the role of the fluid velocity. It is found that the Mach cone separates two regions of the diffraction pattern: inside the Mach cone oblique dark solitons are generated and outside the Mach cone the region of ""optical ship waves"" (the wave pattern formed by a two-dimensional packet of linear waves) is situated. Analytical theory of the ""optical ship waves"" is developed and two-dimensional dark soliton solutions of the generalized two-dimensional nonlinear Schrodinger equation describing the light beam propagation are found. Stability of dark solitons with respect to their decay into vortices is studied and it is shown that they are stable for large enough values of the Mach number.

On the wake-induced vibration of tandem circular cylinders: the vortex interaction excitation mechanism

The mechanism of wake-induced vibrations (WIV) of a pair of cylinders in a tandem arrangement is investigated by experiments. A typical WIV response is characterized by a build-up of amplitude persisting to high reduced velocities; this is different from a typical vortex-induced vibration (VIV) response, which occurs in a limited resonance range. We suggest that WIV of the downstream cylinder is excited by the unsteady vortex-structure interactions between the body and the upstream wake. Coherent vortices interfering with the downstream cylinder induce fluctuations in the fluid force that are not synchronized with the motion. A favourable phase lag between the displacement and the fluid force guarantees that a positive energy transfer from the flow to the structure sustains the oscillations. If the unsteady vortices are removed from the wake of the upstream body then WIV will not be excited. An experiment performed in a steady shear flow turned out to be central to the understanding of the origin of the fluid forces acting on the downstream cylinder.

Investigation of Normal Force and Moment Coefficients for an AUV at Nonlinear Angle of Attack and Sideslip Range

This paper presents a comparative study of computational fluid dynamics (CFD) and analytical and semiempirical (ASE) methods applied to the prediction of the normal force and moment coefficients of an autonomous underwater vehicle (AUV). Both methods are applied to the. bare hull of the vehicle and to the body-hydroplane combination. The results are validated through experiments in a towing tank. It is shown that the CFD approach allows for a good prediction of the coefficients over the range of angles of attack considered. In contrast with the traditional ASE formulations used in naval and aircraft fields, an improved methodology is introduced that takes advantage of the qualitative information obtained from CFD flow visualizations.

Negative ion `chip-based` nanospray tandem mass spectrometry for the analysis of flavonoids in glandular trichomes of Lychnophora ericoides Mart. (Asteraceae)

This paper reports a method for the analysis of secondary metabolites stored in glandular trichomes, employing negative ion `chip-based` nanospray tandem mass spectrometry. The analyses of glandular trichomes from Lychnophora ericoides, a plant endemic to the Brazilian `cerrado` and used in traditional medicine as an anti-inflammatory and analgesic agent, led to the identification of five flavonoids (chrysin, pinocembrin, pinostrobin, pinobanksin and 3-O-acetylpinobanksin) by direct infusion of the extracts of glandular trichomes into the nanospray ionisation source. All the flavonoids have no oxidation at ring B, which resulted in a modification of the fragmentation pathways compared with that of the oxidised 3,4-dihydroflavonoids already described in the literature. The absence of the anti-inflammatory and antioxidant di-C-glucosylflavone vicenin-2, or any other flavonoid glycosides, in the glandular trichomes was also demonstrated. The use of the,`chip-based` nanospray QqTOF apparatus is a new fast and useful tool for the identification of secondary metabolites stored in the glandular trichomes, which can be useful for chemotaxonomic studies based on metabolites from glandular trichomes. Copyright (C) 2008 John Wiley & Sons, Ltd.

In vitro studies of cutaneous retention of magnetic nanoemulsion loaded with zinc phthalocyanine for synergic use in skin cancer treatment

In this study was developed a new nano drug delivery system (NDDS) based on association of biodegradable surfactants with biocompatible magnetic fluid of maguemita citrate derivative. This formulation consists in a magnetic emulsion with nanostructured colloidal particles. Preliminary in vitro experiments showed that the formulation presents a great potential for synergic application in the topical release of photosensitizer drug (PS) and excellent target tissue properties in the photodynamic therapy (PDT) combined with hyperthermia (HPT) protocols. The physical chemistry characterization and in vitro assays were carried out by Zn(II) Phtalocyanine (ZnPc) photosensitizer incorporated into NDDS in the absence and the presence of magnetic fluid, showed good results and high biocompatibility. In vitro experiments were accomplished by tape-stripping protocols for quanti. cation of drug association with different skin tissue layers. This technique is a classical method for analyses of drug release in stratum corneum and epidermis+ dermis skin layers. The NDDS formulations were applied directly in pig skin (tissue model) fixed in the cell`s Franz device with receptor medium container with a PBS/EtOH 20% solution (10mM, pH 7.4) at 37 degrees C. After 12 h of topical administration stratum corneum was removed from fifty tapes and the ZnPc retained was evaluated by solvent extraction in dimetil-sulphoxide under ultrasonic bath. These results indicated that magnetic nanoemulsion (MNE) increase the drug release on the deeper skin layers when compared with classical formulation in the absence of magnetic particles. This could be related with the increase of biocompatibility of NDDS due to the great affinity for the polar extracelullar matrix in the skin and also for the increase in the drug partition inside of corneocites wall. (C) 2008 Elsevier B.V. All rights reserved.

Influence of insulin treatment on the lacrimal gland and ocular surface of diabetic rats

Previous studies have observed changes in the lacrimal gland and ocular surface related to diabetes mellitus and related it to insulin resistance or insufficiency and oxidative damage. The aim of this study was to evaluate whether insulin treatment inhibits those changes. Diabetes was induced in male Wistar rats with a single intravenous injection of streptozotocin and a subgroup was treated with insulin. After 5 and 10 weeks, the three groups (n = 5-10/group/experimental procedure) were compared for biochemical, functional, and histological parameters. After 5 weeks, changes in morphology and increased numbers of lipofucsin-like inclusions were observed in lacrimal glands of diabetic but not insulin-treated rats. After 5 weeks, malonaldehyde and total peroxidase activity were significantly higher in diabetic rats, but similar to control in insulin-treated diabetic rats (P = 0.03, P = 0.02, respectively). Our data indicate that diabetes induces histological alterations in lacrimal gland and suggests that hyperglycemia-related oxidative stress may participate in diabetic dry eye syndrome. Prevention by insulin replacement suggests direct hormone action and/or benefit by early sub optimal metabolic control.

Intellectuals in a Network A New Generation Faces the Challenges of Development

Brazilian social thought draws on the inspiration of past masters the common denominator of whose work is probably a deep humanism. Confronting the challenges of a fluid, ever-changing reality is now a matter of survival. The idea of climate change has made the environment, long relegated to second place, a matter of much wider interest and concern. The other great problem is poverty, and here, while there have been undeniable advances, much remains to be done. The main challenge is producing forms of social organization that will allow ordinary citizens to have an impact on what really matters. Developing policy in these areas has engaged the efforts of a wide range of experts from a variety of fields. Whereas university-educated intellectuals once formed an intelligentsia, today they are engaged in practical politics and much more often function as agents who link social actors together than as mere elaborators of theories.

Efficacy and safety of iodopovidone pleurodesis in malignant pleural effusions

Background and objective: Pleurodesis is one of the best methods of controlling malignant pleural effusions (MPE), a distressing complication of metastatic disease. In recent studies of a wide range of pleural diseases, iodopovidone was used as a sclerosing agent for pleurodesis and demonstrated good results with low morbidity. The aim of this study was to evaluate the efficacy and safety of iodopovidone pleurodesis in MPE. Methods: A retrospective analysis was performed on patients with MPE who underwent pleurodesis at our institution between 2005 and 2008. All patients underwent instillation of 20 mL of 10% iodopovidone, 80 mL of normal saline and 2 mg/kg of lidocaine through a chest tube, which was clamped for 2 h. The tube was removed when the daily output of fluid was < 200 mL. Data on the requirement for additional pleural procedures, adverse events and survival were collected. Results: Sixty-one pleurodesis procedures were performed in 54 patients. No procedure-related mortality was observed. Adverse events occurred after 11 (18%) pleurodesis procedures. The most frequent complication was mild thoracic pain that occurred immediately after 10 (16.4%) procedures, and one patient developed pleural empyema that was treated with drainage and antibiotics. A success rate of 98.4% was observed. Except for the patient who developed pleural empyema, none of the other patients had recurrences of pleural fluid or required additional pleural procedures during the follow-up period (mean of 5.6 months). Conclusions: Iodopovidone pleurodesis was successful and was associated with only a few minor complications. It appears to be a good option for the management of recurrent MPE.

Cytokine Profile in Pleural Fluid and Serum After Lung Transplantation

Background. Lung transplantation is the procedure of choice in several end-stage lung diseases. Despite improvements in surgical techniques and immunosuppression, early postoperative complications occur frequently. Objective. To evaluate the pleural inflammatory response after surgery. Patients and Methods. Twenty patients aged 18 to 63 years underwent unilateral or bilateral lung transplantation between August 2006 and March 2008. Proinflammatory cytokines interleukin (IL)-1 beta, IL-6, and IL-8 and vascular endothelial growth factor in pleural fluid and serum were analyzed. For cytokine evaluation, 20-mL samples of pleural fluid and blood (right, left, or both chest cavities) were obtained at 6 hours after surgery and daily until removal of the chest tube or for a maximum of 10 days. Data were analyzed using analysis of variance followed by the Holm-Sidak test. Results. All effusions were exudates according to Light`s criteria. Pleural fluid cytokine concentrations were highest at 6 hours after surgery. Serum concentrations were lower than those in pleural fluid, and IL-1 beta, IL-6, and IL-8 were undetectable at all time points. Conclusions. There is a peak concentration of inflammatory cytokines in the first 6 hours after transplantation, probably reflecting the effects of surgical manipulation. The decrease observed from postoperative day 1 and thereafter suggests the action of the immunosuppression agents and a temporal reduction in pleural inflammation.

Disease-modifying properties of long-term lithium treatment for amnestic mild cognitive impairment: randomised controlled trial

Background Two recent clinical studies support the feasibility of trials to evaluate the disease-modifying properties of lithium in Alzheimer`s disease, although no benefits were obtained from short-term treatment. Aims To evaluate the effect of long-term lithium treatment on cognitive and biological outcomes in people with amnestic mild cognitive impairment (aMCI). Method Forty-five participants with aMCI were randomised to receive lithium (0.25-0.5mmol/l) (n=24) or placebo (n = 21) in a 12-month, double-blind trial. Primary outcome measures were the modification of cognitive and functional test scores, and concentrations of cerebrospinal fluid (CSF) biomarkers (amyloid-beta peptide (A beta(42)), total tau (T-tau), phosphorylated-tau) (P-tau). Trial registration: NCT01055392. Results Lithium treatment was associated with a significant decrease in CSF concentrations of P-tau (P=0.03) and better perform-ance on the cognitive subscale of the Alzheimer`s Disease Assessment Scale and in attention tasks. Overall tolerability of lithium was good and the adherence rate was 91%. Conclusions The present data support the notion that lithium has disease-modifying properties with potential clinical implications in the prevention of Alzheimer`s disease.

Characterization of juvenile and young adult mice following induction of hydrocephalus with kaolin

Hydrocephalus is a common neurological problem in humans, Usually caused by an impairment of cerebrospinal fluid (CSF) flow or absorption. A reliable induced model of chronic hydrocephalus in mice would be useful to test hypotheses using genetic mutants. Our goal was to characterize behavioral and histological changes in juvenile and Young adult mice with kaolin (aluminum silicate) -induced hydrocephalus. Seven-day old and 7-8 week old mice received injection of kaolin into the cisterna magna. Behavior was assessed repeatedly. Seven or 14 days following kaolin, magnetic resonance (MR) imaging was used to assess ventricle size. In hydrocephalic mice, body weight was significantly lower than in age-matched saline-injected sham controls and the gait and posture score were impaired. Juvenile mice developed severe ventriculomegaly and had reduced corpus callosum thickness with gross white matter destruction by 14 days. Reactive astroglial change in white matter and cortex and reduced cellular proliferation in the subependymal zone were also apparent. Young adult mice developed only moderate ventricular enlargement without overt white matter destruction, although there was corpus callosum atrophy and mild astroglial reaction in white matter. Glial fibrillary acidic protein content was significantly higher in juvenile and young adult hydrocephalic mice at 7 and 14 days, but myelin basic protein content was not significantly altered. In conclusion, hydrocephalus induced by percutaneous injection of kaolin in juvenile and young adult mice is feasible. The associated periventricular alterations are essentially the same as those reported in rats of comparable ages. (C) 2009 Elsevier Inc. All rights reserved.

Occult risk factor for the development of cerebral edema in children with diabetic ketoacidosis: possible role for stomach emptying

The incidence of cerebral edema during therapy of diabetic ketoacidosis (DKA) in children remains unacceptably high-this suggests that current treatment may not be ideal and that important risk factors for the development of cerebral edema have not been recognized. We suggest that there are two major sources for an occult generation of osmole-free water in these patients: first, fluid with a low concentration of electrolytes that was retained in the lumen of the stomach when the patient arrived in hospital; second, infusion of glucose in water at a time when this solution can be converted into water with little glucose. In a retrospective chart review of 30 patients who were admitted with a diagnosis of DKA and a blood sugar > 900 mg/dL (50 mmol/L), there were clues to suggest that some of the retained fluid in the stomach was absorbed. To minimize the likelihood of creating a dangerous degree of cerebral edema in patients with DKA, it is important to define the likely composition of fluid retained in the stomach on admission, to look for signs of absorption of some of this fluid during therapy, and to be especially vigilant once fat-derived brain fuels have disappeared, because this is the time when glucose oxidation in the brain should increase markedly, generating osmole-free water.

Effects of individual housing on behavior and resistance to Ehrlich tumor growth in mice

This study analyzed in Balb/C mice the effects of individual housing on behavior, serum corticosterone and resistance to Ehrlich tumor growth. Mice (60 days old) were individually (IH) or grouped housed (G) (10-12 animals/cage) for 14-21 days. The 1st day of the housing condition was considered experimental day 1 (ED1). Results showed that on ED21, IH mice, when compared to G mice, presented no differences on corticosterone serum levels when kept undisturbed; however, an increased level of this hormone was observed in IH mice after an immobilization stress challenge. An increased time spent in the plus-maze closed arms and a decreased time in the open arms were also observed in IH mice. When compared to G animals, after inoculation with 105 Ehrlich tumor cells on ED1, IH mice presented an increase in volume of ascitic fluid and number of tumor cells. The survival time of IH mice was also shorter than that measured in G animals. Furthermore, IH mice injected with a different number of tumor cells on ED1 always presented increased Ehrlich tumor cells than G group. Interestingly. these effects were not observed when the tumor cells injection was done on ED4. These results suggest that individual-housing conditions induce an altered immune-endocrine response and, at the same time, decrease animals` resistance to Ehrlich tumor growth. It is proposed that the neural link between the behavioral and immunological changes observed after the stress of individual housing might involve the activation of the HPA axis. (C) 2008 Elsevier Inc. All rights reserved.