60 resultados para SELECTIVE SEPARATIONS


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Although melatonin is mainly produced by the pineal gland, an increasing number of extra-pineal sites of melatonin synthesis have been described. We previously demonstrated the existence of bidirectional communication between the pineal gland and the immune system that drives a switch in melatonin production from the pineal gland to peripheral organs during the mounting of an innate immune response. In the present study, we show that acute neuroinflammation induced by lipopolysaccharide (LPS) injected directly into the lateral ventricles of adult rats reduces the nocturnal peak of melatonin in the plasma and induces its synthesis in the cerebellum, though not in the cortex or hippocampus. This increase in cerebellar melatonin content requires the activation of nuclear factor kappa B (NF-κB), which positively regulates the expression of the key enzyme for melatonin synthesis, arylalkylamine N-acetyltransferase (AA-NAT). Interestingly, LPS treatment led to neuronal death in the hippocampus and cortex, but not in the cerebellum. This privileged protection of cerebellar cells was abrogated when G-protein-coupled melatonin receptors were blocked by the melatonin antagonist luzindole, suggesting that the local production of melatonin protects cerebellar neurons from LPS toxicity. This is the first demonstration of a switch between pineal and extra-pineal melatonin production in the central nervous system following a neuroinflammatory response. These results have direct implications concerning the differential susceptibility of specific brain areas to neuronal death.

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Selective neck dissection (SND) in clinical N-0 (cN(0)) cases of oral squamous cell carcinoma (SCC) has been performed by surgeons using a retroauricular or modified facelift approach with robotic or endoscopic assistance. However, these procedures provide cosmetic satisfaction at the cost of possible maximal invasiveness. In this prospective study, we introduced and evaluated the feasibility as well as surgical invasiveness and cosmetic outcome of endoscopically-assisted SND via a small submandibular approach.Forty-four patients with cT(1-2)N(0) oral SCC (OSCC) were randomly divided into two groups of endoscopically-assisted SND and conventional SND. Perioperative and postoperative outcomes of patients were evaluated, including the length of the incision, operating time for neck dissection, estimated blood loss during the operation, amount and duration of drainage, total hospitalization period, total number of lymph nodes retrieved, satisfaction scores based on the cosmetic results, perioperative local complications, shoulder syndrome, and follow-up information.The mean operation time in the endoscopically-assisted group (126.04 +/- A 12.67 min) was longer than that in the conventional group (75.67 +/- A 16.67 min). However, the mean length of the incision was 4.33 +/- A 0.76 cm in the endoscopically-assisted SND group, and the amount and duration of drainage, total hospital stay, postoperative shoulder pain score, and cosmetic outcomes were superior in the endoscopically-assisted SND group. Additionally, the retrieved lymph nodes and complications were comparable.Endoscopically-assisted SND via a small submandibular approach had a longer operation time than the conventional approach. However, endoscopically-assisted SND was feasible and reliable while providing minimal invasiveness and satisfactory appearance.

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A new selective sensor based on molecularly imprinted polymers (MIPs) was developed for the determination of hexazinone (HXZ) in environmental samples. MIPs were synthesized using a non-covalent approach, and selection of the monomers employed in the polymerization reaction was carried out by molecular modeling. Three functional monomers with high (2-vinylpyridine (MP17)) and intermediate (methacrylic acid (MP12) and acrylamide (MP5)) energies of binding to the template (HXZ) were selected for preparation of the MIPs, in order to conduct comparative studies and validate the theoretical data. For sensor construction, carbon pastes were modified with each MIP or NIP (non-imprinted polymer), and HXZ determination was performed using differential pulse adsorptive cathodic stripping voltammetry (DPAdCSV). All parameters affecting the sensor response were optimized. In HCl at pH 2.5, the sensor prepared with MP17 (5% w/w in the paste) showed a dynamic linear range between 1.9 × 10−11 and 1.1 × 10−10 mol L−1, and a detection limit of 2.6 × 10−12 mol L−1, under the following conditions: accumulation time of 200 s at a potential of −0.5V, scan rate of 50 mVs−1, pulse amplitude of 60 mV, and pulse width of 50 ms. The sensor was selective in the presence of other similar compounds, and was successfully applied to the analysis of HXZ in river water samples.

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The influence of both thermal treatment and laser irradiation on the structural and optical properties of films in the Sb 2 O 3 –Sb 2 S 3 system was investigated. The films were prepared by RF-sputtering using glass compositions as raw materials. Irreversible photodarkening effect was observed after exposure the films to a 458nm solid state laser. It is shown, for the first time, the use of holographic technique to measure “in situ”, simultaneously and independently, the phase and amplitude modulations in glassy films. The films were also photo-crystallized and analysed “in situ” using a laser coupled to a micro-Raman equipment. Results showed that Sb 2 S 3 crystalline phase was obtained after irradiation. The effect of thermal annealing on the structure of the films was carried out. Different from the result obtained by irradiation, thermal annealing induces the crystallization of the Sb 2 O 3 phase. Photo and thermal induced effects on films were studied using UV–Vis and Raman spectroscopy, atomic force microscopy (AFM), thermal analysis (DSC), X-ray diffraction, scanning electron microscopy (MEV) and energy-dispersive X-ray spectroscopy (EDX).

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

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Shoulder arthroscopic surgeries evolve with intense postoperative pain. Several analgesic techniques have been advocated. The aim of this study was to compare suprascapular and axillary nerve blocks in shoulder arthroscopy using the interscalene approach to brachial plexus blockade. According to the technique used, sixty-eight patients were allocated into two groups: interscalene group (IG, n=34) and selective group (SG, n=34), with neurostimulation approach used for both techniques. After appropriate motor response, IG received 30 mL of 0.33% levobupivacaine in 50% enantiomeric excess with adrenalin 1:200,000. After motor response of suprascapular and axillary nerves, SG received 15 mL of the same substance on each nerve. General anesthesia was then administered. Variables assessed were time to perform the blocks, analgesia, opioid consumption, motor block, cardiovascular stability, patient satisfaction and acceptability. Time for interscalene blockade was significantly shorter than for selective blockade. Analgesia was significantly higher in the immediate postoperative period in IG and in the late postoperative period in SG. Morphine consumption was significantly higher in the first hour in SG. Motor block was significantly lower in SG. There was no difference between groups regarding cardiocirculatory stability and patient satisfaction and acceptability. Failure occurred in IG (1) and SG (2). Both techniques are safe, effective, and with the same degree of satisfaction and acceptability. The selective blockade of both nerves showed satisfactory analgesia, with the advantage of providing motor block restricted to the shoulder.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This work presents an efficient method for the preparation of magnetic nanoparticles modified with molecularly imprinted polymers (Mag-MIP) through core-shell method for the determination of biotin in milk food samples. The functional monomer acrylic acid was selected from molecular modeling, EGDMA was used as cross-linking monomer and AIBN as radical initiator. The Mag-MIP and Mag-NIP were characterized by FTIR, magnetic hysteresis, XRD, SEM and N2-sorption measurements. The capacity of Mag-MIP for biotin adsorption, its kinetics and selectivity were studied in detail. The adsorption data was well described by Freundlich isotherm model with adsorption equilibrium constant (KF) of 1.46 mL g(-1). The selectivity experiments revealed that prepared Mag-MIP had higher selectivity toward biotin compared to other molecules with different chemical structure. The material was successfully applied for the determination of biotin in diverse milk samples using HPLC for quantification of the analyte, obtaining the mean value of 87.4% recovery.

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Brucellosis remains as a public health concern worldwide. In domestic animals, the disease is characterized by reproductive disorders in male and female. Besides extensive use of serological tests and recent development of molecular biology techniques, microbiological culture of Brucella species is yet considered a “gold standard” method for diagnosis. Here, semen of 335 bovine bulls was subjected simultaneously to microbiological culture in Brucella agar, Farrell media, and CITA media to evaluate comparatively the best selective media for isolation of Brucella sp. Among all 335 samples, B. abortus B19 strain was isolated from semen of five (1.49%) bulls using the three selective media. However, Farrell media was considered the best selective media for microbiological diagnosis, because of allowed isolation of B. abortus B19 strain from bull semen without bacterial commensal or fungal contamination of plates.