895 resultados para PTFE facial membranes


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The controlled release of drugs can be efficient if a suitable encapsulation procedure is developed, which requires biocompatible materials to hold and release the drug. In this study, a natural rubber latex (NRL) membrane is used to deliver metronidazole (MET), a powerful antiprotozoal agent. MET was found to be adsorbed on the NRL membrane, with little or no incorporation into the membrane bulk, according to energy dispersive X-ray spectroscopy. X-ray diffraction and FTIR spectroscopy data indicated that MET retained its structural and spectroscopic properties upon encapsulation in the NRL membrane, with no molecular-level interaction that could alter the antibacterial activity of MET. More importantly, the release time of MET in a NRL membrane in vitro was increased from the typical 6-8 h for oral tablets or injections to ca. 100 h. The kinetics of the drug release could be fitted with a double exponential function, with two characteristic times of 3.6 and 29.9 h. This is a demonstration that the induced angiogenesis known to be provided by NRL membranes can be combined with a controlled release of drugs, whose kinetics can be tailored by modifying experimental conditions of membrane fabrication for specific applications. (C) 2010 Elsevier B.V. All rights reserved.

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We describe the assembly of layer-by-layer films based on the poly(propylene imine) dendrimer (PPID) generation 3 and nickel tetrasulfonated phthalocyanine (NiTsPc) for application as chemically sensitive membranes in sepal alive extended-gate field effect transistor (SEGFET) pH sensors PPID/NiTsPc films wet e adsorbed on quartz, glass. indium tin oxide. or gold (Au)-covered glass substrates Multilayer formation was monitored via UV-vis absorption upon following the increment in the Q-band intensity (615 nm) of NiTsPc The nanostructured membranes were very stable in a pH range of 4-10 and displayed a good sensitivity toward H(+), ca 30 mV/pH for PPID/N(1)TsPc films deposited on Au-covered substrates For films deposited on ITO, the sensitivity was ca 52 4 mV/pH. close to the expected theoretical value for ton-sensitive membranes. The use of chemically stable PPID/NiTsPc films as gate membranes in SEGFETs, as introduced here, may represent an alternative for the fabrication of nanostructured, porous platforms for enzyme immobilization to be used in enzymatic biosensors.

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Diacylglycerol acyltransferase 1 (DGAT1) catalyzes the final and dedicated step in the synthesis of triacylglycerol, which is believed to involve the lipids oleoyl coenzyme A (OCoA) and dioleoyl-sn-glycerol (DOG) as substrates. In this work we investigated the interaction of a specific peptide, referred to as SIT2, on the C-terminal of DGAT1 (HKWCIRHFYKP) with model membranes made with OCoA and DOG in Langmuir monolayers and liposomes. According to the circular dichroism and fluorescence data, conformational changes on SIT2 were seen only on liposomes containing OCoA and DOG. In Langmuir monolayers, SIT2 causes the isotherms of neat OCoA and DOG monolayers to be expanded, but has negligible effect on mixed monolayers of OCoA and DOG. This synergistic interaction between SIT2 and DOG + OCoA may be rationalized in terms of a molecular model in which SIT2 may serve as a linkage between the two lipids. Our results therefore provide molecular-level evidence for the interaction between this domain and the substrates OCoA and DOG for the synthesis of triacylglycerol. (C) 2009 Elsevier B.V. All rights reserved.

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We describe a simple and efficient strategy to fabricate enzymatic devices based on the deposition of glucose oxidase on aligned and highly oriented CoNiMo metallic nanowires. CoNiMo nanowires with an average diameter of 200 nm and length of 50 mu m were electrodeposited on Au-covered alumina substrates via electrodeposition, using alumina membranes as templates. Enzyme-modified electrodes were fabricated via enzyme immobilization using a cross-linker. To minimize nonspecific reactions in the presence of interfering agents, a permselective membrane composed of poly(vinylsulfonic acid) and polyamidoamine dendrimer was deposited via electrostatic interaction. The formation of hydrogen peroxide as a product of the enzymatic reaction was monitored at low overpotential, 0.0 V (vs Ag/AgCl). The detection limit was estimated at 22 mu M under an applied potential of 0.0 V. The apparent Michaelis-Menten constant determined from the Lineweaver-Burke plot was 2 mM.

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Polycarbonate membranes (PCM) of various pores sizes (400, 200, 100 and 50 nm) were used as templates for gold deposition. The electrodeposition from gold ions resulted in the formation of gold nanotubes when large pores size PCMs (400 and 200 nm) were used. On the other hand, gold nanowires were predominant for the PCMs with smaller pores size (100 and 50 nm). Surface-enhanced Raman scattering (SERS) from the probe molecule 4-mercaptopyridine (4-MPy) was obtained from all these nanostructures. The SERS efficiency of the substrates produced using the PC M templates were compared to two commonly used SERS platforms: a roughened gold electrode and gold nanostructures electrodeposited through organized polystyrene spheres (PSS). The SERS signal of the probe molecule increased as the pore diameter of the PCM template decreased. Moreover, the SERS efficiency from the nanostructures produced using 50 nm PCM templates was four and two times better than the signal from the roughened gold electrode and the PSS template, respectively. The SERS substrates prepared using PCM templates were more homogenous over a larger area (ca. 1 cm(2)), presented better spatial and sample to sample reproducibility than the other substrates. These results show that SERS substrates prepared using PCM templates are promising for the fabrication of planar SERS platforms for analytical/bioanalytical applications.

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Oroidin was isolated from the marine sponge Agelas sventres and inhibited the activity and function of Pdr5p, an enzyme responsible for the multidrug resistance phenotype in Saccharomyces cerevisiae. This compound may help in the development of new drugs that reverse this dangerous phenotype of pathogenic yeast and fungi.

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Sign language animations can lead to better accessibility of information and services for people who are deaf and have low literacy skills in spoken/written languages. Due to the distinct word-order, syntax, and lexicon of the sign language from the spoken/written language, many deaf people find it difficult to comprehend the text on a computer screen or captions on a television. Animated characters performing sign language in a comprehensible way could make this information accessible. Facial expressions and other non-manual components play an important role in the naturalness and understandability of these animations. Their coordination to the manual signs is crucial for the interpretation of the signed message. Software to advance the support of facial expressions in generation of sign language animation could make this technology more acceptable for deaf people. In this survey, we discuss the challenges in facial expression synthesis and we compare and critique the state of the art projects on generating facial expressions in sign language animations. Beginning with an overview of facial expressions linguistics, sign language animation technologies, and some background on animating facial expressions, a discussion of the search strategy and criteria used to select the five projects that are the primary focus of this survey follows. This survey continues on to introduce the work from the five projects under consideration. Their contributions are compared in terms of support for specific sign language, categories of facial expressions investigated, focus range in the animation generation, use of annotated corpora, input data or hypothesis for their approach, and other factors. Strengths and drawbacks of individual projects are identified in the perspectives above. This survey concludes with our current research focus in this area and future prospects.

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The objective of this thesis work, is to propose an algorithm to detect the faces in a digital image with complex background. A lot of work has already been done in the area of face detection, but drawback of some face detection algorithms is the lack of ability to detect faces with closed eyes and open mouth. Thus facial features form an important basis for detection. The current thesis work focuses on detection of faces based on facial objects. The procedure is composed of three different phases: segmentation phase, filtering phase and localization phase. In segmentation phase, the algorithm utilizes color segmentation to isolate human skin color based on its chrominance properties. In filtering phase, Minkowski addition based object removal (Morphological operations) has been used to remove the non-skin regions. In the last phase, Image Processing and Computer Vision methods have been used to find the existence of facial components in the skin regions.This method is effective on detecting a face region with closed eyes, open mouth and a half profile face. The experiment’s results demonstrated that the detection accuracy is around 85.4% and the detection speed is faster when compared to neural network method and other techniques.

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Needle fear is a common problem in children undergoing immunization. To ensure that the individual child's needs are met during a painful procedure it would be beneficial to be able to predict whether there is a need for extra support. The self-reporting instrument facial affective scale (FAS) could have potential for this purpose. The aim of this study was to evaluate whether the FAS can predict pain unpleasantness in girls undergoing immunization. Girls, aged 11-12 years, reported their expected pain unpleasantness on the FAS at least two weeks before and then experienced pain unpleasantness immediately before each vaccination. The experienced pain unpleasantness during the vaccination was also reported immediately after each immunization. The level of anxiety was similarly assessed during each vaccination and supplemented with stress measures in relation to the procedure in order to assess and evaluate concurrent validity. The results show that the FAS is valid to predict pain unpleasantness in 11-12-year-old girls who undergo immunizations and that it has the potential to be a feasible instrument to identify children who are in need of extra support to cope with immunization. In conclusion, the FAS measurement can facilitate caring interventions.

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Needle fear is a common problem in children undergoing immunization. To ensure that the individual child’s needs are met during a painful procedure it would be beneficial to be able to predict whether there is a need for extra support. The self-reporting instrument facial affective scale (FAS) could have potential for this purpose. The aim of this study was to evaluate whether the FAS can predict pain unpleasantness in girls undergoing immunization. Girls, aged 11-12 years, reported their expected pain unpleasantness on the FAS at least two weeks before and then experienced pain unpleasantness immediately before each vaccination. The experienced pain unpleasantness during the vaccination was also reported immediately after each immunization. The level of anxiety was similarly assessed during each vaccination and supplemented with stress measures in relation to the procedure in order to assess and evaluate concurrent validity. The results show that the FAS is valid to predict pain unpleasantness in 11-12-year-old girls who undergo immunizations and that it has the potential to be a feasible instrument to identify children who are in need of extra support to cope with immunization. In conclusion, the FAS measurement can facilitate caring interventions.

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Women’s faces tend to naturally retain more neonate features than men. These features, such as a greater eye height, a smaller nose area, and a wider smile, would cause women to have more immature faces than males. Interestingly, women who have these facial features are often perceived as more attractive than women with mature facial features. These findings imply that women would be judged less competent than men, and that immature-faced women would be perceived as less competent and more attractive than mature-faced females. Given the direction of political leadership in our country, this has interesting implications for females that are vying for leadership positions. Thus, our study examined the effects of both candidate gender and facial features on voting likelihood, and perceptions of attractiveness and competence, by pairing pictures with neutral party platforms.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Background: Pythiosis in horses is a proliferative and ulcerative disease that primarily affects the skin and subcutaneous tissue of limbs, thoracic-abdominal region and head. This disease sometimes can also affect limb bones or cause tumoral masses in abdomen. Usually, the cutaneous cases are confused with habronemiasis. The disease is more common in marshy areas, places with formation of slow drainage ponds and aquatic vegetation under high temperatures. The aim of this study was to describe the development of facial lesions in a horse caused by pythiosis in Cuiaba, Mato Grosso, and, additionally to discuss relevant issues regarding the diagnosis, clinical course and response to immunotherapy treatment.Case: One five years old mare of unknown breed, created in property located in the Cerrado region, had a wound on its face difficult to be healed and non-responsive to several treatments based on ivermectin and organophosphate administrated by either topical or systemic via. The animal was assisted on the farm of origin by the veterinary team of the Clinical Medicine sector, of the Veterinary Hospital, Universidade Federal de Mato Grosso (HOVET-UFMT). on the occasion of the visit, which occurred 60 days after onset of signs, the animal showed a circular single large lesion, ulcerative with serous discharge on the right part of its face, between the eyes and nostrils. There were some necrotic foci with sinus, from which kunkers were extracted; a condition compatible with pythiosis. The diagnosis was confirmed by histology, ELISA and PCR.Discussion: Assuming pythiosis from data obtained from the survey and profile of the lesion (secretory aspect, emaciation and presence of sinus and kunkers), immunotherapy treatment was immediately applied. The advanced clinical aspects and the fact that early diagnosis and treatment are essentials to satisfactory therapeutic response were also taken into consideration for starting the treatment. The remission of signs was achieved after five subcutaneous applications with 14 days between each application. From the second application, it was observed clinical improvement and after 60 days of treatment there was almost complete remission of signs. The signs for a satisfactory response in the injury site followed the order of decreasing secretory aspect, decreasing borders, decrease the itching and bringing the edges together with the formation of a thin layer of crust on the surface. Pythiosis cases with lesions on the face and lower abdomen are commonly confused with habronemiasis by macroscopic and widespread similarity between technicians and attendants, and essential support to the diagnosis through laboratory tests, which in turn are still underutilized. In this case, the authors demonstrated the therapeutic efficacy of immunotherapy as an advantage, considering the possibility of applying it in cases of lesions in areas of difficult surgical access, treatment conditions in the field, with low cost and ease of application. Further studies approaching this alternative therapy are necessary, since side effects have been observed in some cases.