991 resultados para Stimulation [beta]3-adrénergique


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The latex dilution reaction during the tapping flow course has been well documented and associated with the facilitation of tapping latex flow. However, its underlying mechanism has not experimentally examined. The latex total solid content, osmotic potential and phloem turgor pressure change during the tapping flow course were simultaneously measured to investigate the cause of water movement during the tapping flow course. It was found that there are three different stages for the laticifer water equilibrium during the tapping flow course. The tapping-induced rapid turgor pressure drop is the cause of the first stage water influx into laticifers, while osmoregulation prevails during water exchange in the second and third stages of tapping flow. Meanwhile, aquaporin expressions were, for the first time, investigated during the tapping flow course. The rapid transcript up-regulation of HbPIP1, HbPIP2;1 and HbPIP2;3 contributes to the latex dilution reaction. However, their activity gating cannot be ruled out. Ethrel stimulation can significantly dilute the corresponding latex fractions during the tapping flow course due to its up-regulations of HbPIP1, HbPIP2;1 and HbPIP2;3. Nevertheless, the latex dilution reaction pattern for the Ethrel treated trees did not change, except for a lower degree of dilution compared with the un-treated trees. All these results suggest that both phloem turgor pressure and aquaporins are involved in the latex dilution reaction during the tapping flow course.

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Rubber tree (Hevea brasiliensis) latex, the source of natural rubber, is synthesised in the cytoplasm of laticifers. Efficient water inflow into laticifers is crucial for latex flow and production since it is the determinant of the total solid content of latex and its fluidity after tapping. As the mature laticifer vessel rings are devoid of plasmodesmata, water exchange between laticifers and surrounding cells is believed to be governed by plasma membrane intrinsic proteins (PIPs). To identify the most important PIP aquaporin in the water balance of laticifers, the transcriptional profiles of ten-latex-expressed PIPs were analysed. One of the most abundant transcripts, designated HbPIP2;3, was characterised in this study. When tested in Xenopus laevis oocytes HbPIP2;3 showed a high efficiency in increasing plasmalemma water conductance. Expression analysis indicated that the HbPIP2;3 gene was preferentially expressed in latex, and the transcripts were up-regulated by both wounding and exogenously applied Ethrel (a commonly-used ethylene releaser). Although regular tapping up-regulated the expression of HbPIP2;3 during the first few tappings of the virginal rubber trees, the transcriptional kinetics of HbPIP2;3 to Ethrel stimulation in the regularly tapped tree exhibited a similar pattern to that of the previously reported HbPIP2;1 in the virginal rubber trees. Furthermore, the mRNA level of HbPIP2;3 was associated with clonal yield potential and the Ethrel stimulation response. Together, these results have revealed the central regulatory role of HbPIP2;3 in laticifer water balance and ethylene stimulation of latex production in Hevea.

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To identify the gene responsible for the production of a β-1,3-glucanase (laminarinase) within crustacea, a glycosyl hydrolase family 16 (GHF16) gene was sequenced from the midgut glands of the gecarcinid land crab, Gecarcoidea natalis and the freshwater crayfish, Cherax destructor. An open reading frame of 1098bp for G. natalis and 1095bp for C. destructor was sequenced from cDNA. For G. natalis and C. destructor respectively, this encoded putative proteins of 365 and 364 amino acids with molecular masses of 41.4 and 41.5kDa. mRNA for an identical GHF16 protein was also expressed in the haemolymph of C. destructor. These putative proteins contained binding and catalytic domains that are characteristic of a β-1,3-glucanase from glycosyl hydrolase family 16. The amino acid sequences of two short 8-9 amino acid residue peptides from a previously purified β-1,3-glucanase from G. natalis matched exactly that of the putative protein sequence. This plus the molecular masses of the putative proteins matching that of the purified proteins strongly suggests that the sequences obtained encode for a catalytically active β-1,3-glucanase. A glycosyl hydrolase family 16 cDNA was also partially sequenced from the midgut glands of other amphibious (Mictyrisplatycheles and Paragrapsus laevis) and terrestrial decapod species (Coenobita rugosus, Coenobita perlatus, Coenobita brevimanus and Birgus latro) to confirm that the gene is widely expressed within this group. There are three possible hypothesised functions and thus evolutionary routes for the β-1,3-glucanase: 1) a digestive enzyme which hydrolyses β-1,3-glucans, 2) an enzyme which cleaves β-1,3-glycosidic bonds within cell walls to release cell contents or 3) an immune protein which can hydrolyse the cell walls of potentially pathogenic micro-organisms.

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Synthesis and complete characterization of some ester functionalized vinylic tellurides bearing an aryl ligand with varying steric and electronic effects bound to tellurium is described. Hydrotelluration of methyl propiolate using Ar2Te2/NaBH4 in methanol results in a mixture of stereoisomers of methyl β-(aryltelluro)acrylates, ArTeCH[double bond, length as m-dash]CHCOOMe (Ar = 4-MeOC6H4, 1A; 1-C10H7, 2A; 2,4,6-Me3C6H2, 3A; C5H5FeC5H4, 4A; 4-Me2NC6H4, 5A; and 2-C4H3S, 6A). The same reaction in ethanol provides isomeric mixtures of the ethyl esters ArTeCH[double bond, length as m-dash]CHCOOEt (1B–6B). However, in the reactions between methyl propiolate and Ar2Te2 (Ar = 2,4,6-Me3C6H2, 4-Me2NC6H4) in isopropanol or t-butanol, no exchange of alkyl groups between the parent ester and the solvent is observed, instead detelluration of the Ar2Te2 to Ar2Te is a competing reaction along with almost exclusive formation of the (Z)-isomers (3Aa, 5Aa). The geometry of the separated stereoisomers is established in solution, with the help of 1H, 13C and 125Te NMR spectrometry. Of particular interest is the observation that 125Te chemical shifts {deshielded in (Z) compared to (E); Δδ = 106–136 ppm} and the geminal heteronuclear coupling constants {2J(1H–125Te) values for (E) are more than seven times that of the corresponding (Z) isomer} can be used to distinguish between liquid isomers. Structural characterization in the solid state by single-crystal X-ray diffraction for the 2Ba, 3Aa, 3Ba, 5Aa, 8 (Z)-isomers as well as for both stereoisomers of 4-Me2NC6H4TeCH[double bond, length as m-dash]CHCOOEt (5Ba and 5Bb) is also presented. The carbonyl O atom of the ester group is invariably involved, at least in the solid state, in a secondary bonding interaction with the Te(II) atom. While an intermolecular Te⋯O interaction gives rise to one-dimensional supramolecular arrays in the crystal lattice of 5Bb with (E) configuration, it is realized intramolecularly in the case of the (Z)-isomers due to the cis position of the chalcogen atoms.

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The recommendations on the intake of long chain omega-3 polyunsaturated fatty acids (n-3 LC-PUFA) vary from eating oily fish ("once to twice per week") to consuming specified daily amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) ("250-500 mg per day"). It is not known if there is a difference in the uptake/bioavailability between regular daily consumption of supplementsvs. consuming fish once or twice per week. In this study, the bioavailability of a daily dose of n-3 LC-PUFA (Constant treatment), representing supplements, vs. a large weekly dose of n-3 LC-PUFA (Spike treatment), representing consuming once or twice per week, was assessed. Six-week old healthy male Sprague-Dawley rats were fed either a Constant treatment, a Spike treatment or Control treatment (no n-3 LC-PUFA), for six weeks. The whole body, tissues and faeces were analysed for fatty acid content. The results showed that the major metabolic fate of the n-3 LC-PUFA (EPA+docosapentaenoic acid (DPA) + DHA) was towards catabolism (β-oxidation) accounting for over 70% of total dietary intake, whereas deposition accounted less than 25% of total dietary intake. It was found that significantly more n-3 LC-PUFA were β-oxidised when originating from the Constant treatment (84% of dose), compared with the Spike treatment (75% of dose). Conversely, it was found that significantly more n-3 LC-PUFA were deposited when originating from the Spike treatment (23% of dose), than from the Constant treatment (15% of dose). These unexpected findings show that a large dose of n-3 LC-PUFA once per week is more effective in increasing whole body n-3 LC-PUFA content in rats compared with a smaller dose delivered daily.

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OBJECTIVE: To investigate the efficacy and effects of transcranial direct current stimulation (tDCS) on motor imagery brain-computer interface (MI-BCI) with robotic feedback for stroke rehabilitation. DESIGN: A sham-controlled, randomized controlled trial. SETTING: Patients recruited through a hospital stroke rehabilitation program. PARTICIPANTS: Subjects (N=19) who incurred a stroke 0.8 to 4.3 years prior, with moderate to severe upper extremity functional impairment, and passed BCI screening. INTERVENTIONS: Ten sessions of 20 minutes of tDCS or sham before 1 hour of MI-BCI with robotic feedback upper limb stroke rehabilitation for 2 weeks. Each rehabilitation session comprised 8 minutes of evaluation and 1 hour of therapy. MAIN OUTCOME MEASURES: Upper extremity Fugl-Meyer Motor Assessment (FMMA) scores measured end-intervention at week 2 and follow-up at week 4, online BCI accuracies from the evaluation part, and laterality coefficients of the electroencephalogram (EEG) from the therapy part of the 10 rehabilitation sessions. RESULTS: FMMA score improved in both groups at week 4, but no intergroup differences were found at any time points. Online accuracies of the evaluation part from the tDCS group were significantly higher than those from the sham group. The EEG laterality coefficients from the therapy part of the tDCS group were significantly higher than those of the sham group. CONCLUSIONS: The results suggest a role for tDCS in facilitating motor imagery in stroke.

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The effects of krill oil as an alternative source of n-3 long-chain PUFA have been investigated recently. There are conflicting results from the few available studies comparing fish oil and krill oil. The aim of this study was to compare the bioavailability and metabolic fate (absorption, β-oxidation and tissue deposition) of n-3 fatty acids originating from krill oil (phospholipid-rich) or fish oil (TAG-rich) in rats of both sexes using the whole-body fatty acid balance method. Sprague-Dawley rats (thirty-six male, thirty-six female) were randomly assigned to be fed either a krill oil diet (EPA+DHA+DPA=1·38 mg/g of diet) or a fish oil diet (EPA+DHA+DPA=1·61 mg/g of diet) to constant ration for 6 weeks. The faeces, whole body and individual tissues were analysed for fatty acid content. Absorption of fatty acids was significantly greater in female rats and was only minimally affected by the oil type. It was estimated that most of EPA (>90 %) and more than half of DHA (>60 %) were β-oxidised in both diet groups. Most of the DPA was β-oxidised (57 and 67 % for female and male rats, respectively) in the fish oil group; however, for the krill oil group, the majority of DPA was deposited (82-83 %). There was a significantly greater deposition of DPA and DHA in rats fed krill oil compared with those fed fish oil, not due to a difference in bioavailability (absorption) but rather due to a difference in metabolic fate (anabolism v. catabolism).

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This paper presents the development of an energy harvesting circuit for use with a head-mountable deep brain stimulation (DBS) device. It consists of a circular planar inverted-F antenna (PIFA) and a Schottky diode-based Cockcroft-Walton 4-voltage rectifier. The PIFA has the volume of π × 10(2) × 1.5 mm(3), resonance frequency of 915 MHz, and bandwidth of 16 MHz (909-925 MHz) at a return loss of -10 dB. The rectifier offers maximum efficiency of 78% for the input power of -5 dBm at a 5 kΩ load resistance. The developed rectenna operates efficiently at 915 MHz for the input power within -15 dBm to +5 dBm. For operating a DBS device, the DC voltage of 2 V is recorded from the rectenna terminal at a distance of 55 cm away from a 26.77 dBm transmitter in free space. An in-vitro test of the DBS device is presented.

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BACKGROUND: Heart failure is associated with high mortality and hospital readmissions. Beta-adrenergic blocking agents, angiotensin converting enzyme inhibitors (ACEIs), and angiotensin receptor blockers (ARBs) can improve survival and reduce hospital readmissions and are recommended as first-line therapy in the treatment of heart failure. Evidence has also shown that there is a dose-dependent relationship of these medications with patient outcomes. Despite this evidence, primary care physicians are reluctant to up-titrate these medications. New strategies aimed at facilitating this up-titration are warranted. Nurse-led titration (NLT) is one such strategy. OBJECTIVES: To assess the effects of NLT of beta-adrenergic blocking agents, ACEIs, and ARBs in patients with heart failure with reduced ejection fraction (HFrEF) in terms of safety and patient outcomes. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials in the Cochrane Library (CENTRAL Issue 11 of 12, 19/12/2014), MEDLINE OVID (1946 to November week 3 2014), and EMBASE Classic and EMBASE OVID (1947 to 2014 week 50). We also searched reference lists of relevant primary studies, systematic reviews, clinical trial registries, and unpublished theses sources. We used no language restrictions. SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing NLT of beta-adrenergic blocking agents, ACEIs, and/or ARBs comparing the optimisation of these medications by a nurse to optimisation by another health professional in patients with HFrEF. DATA COLLECTION AND ANALYSIS: Two review authors (AD & JC) independently assessed studies for eligibility and risk of bias. We contacted primary authors if we required additional information. We examined quality of evidence using the GRADE rating tool for RCTs. We analysed extracted data by risk ratio (RR) with 95% confidence interval (CI) for dichotomous data to measure effect sizes of intervention group compared with usual-care group. Meta-analyses used the fixed-effect Mantel-Haenszel method. We assessed heterogeneity between studies by Chi(2) and I(2). MAIN RESULTS: We included seven studies (1684 participants) in the review. One study enrolled participants from a residential care facility, and the other six studies from primary care and outpatient clinics. All-cause hospital admission data was available in four studies (556 participants). Participants in the NLT group experienced a lower rate of all-cause hospital admissions (RR 0.80, 95% CI 0.72 to 0.88, high-quality evidence) and fewer hospital admissions related to heart failure (RR 0.51, 95% CI 0.36 to 0.72, moderate-quality evidence) compared to the usual-care group. Six studies (902 participants) examined all-cause mortality. All-cause mortality was also lower in the NLT group (RR 0.66, 95% CI 0.48 to 0.92, moderate-quality evidence) compared to usual care. Approximately 27 deaths could be avoided for every 1000 people receiving NLT of beta-adrenergic blocking agents, ACEIs, and ARBs. Only three studies (370 participants) reported outcomes on all-cause and heart failure-related event-free survival. Participants in the NLT group were more likely to remain event free compared to participants in the usual-care group (RR 0.60, 95% CI 0.46 to 0.77, moderate-quality evidence). Five studies (966 participants) reported on the number of participants reaching target dose of beta-adrenergic blocking agents. This was also higher in the NLT group compared to usual care (RR 1.99, 95% CI 1.61 to 2.47, low-quality evidence). However, there was a substantial degree of heterogeneity in this pooled analysis. We rated the risk of bias in these studies as high mainly due to a lack of clarity regarding incomplete outcome data, lack of reporting on adverse events associated with the intervention, and the inability to blind participants and personnel. Participants in the NLT group reached maximal dose of beta-adrenergic blocking agents in half the time compared with participants in usual care. Two studies reported on adverse events; one of these studies stated there were no adverse events, and the other study found one adverse event but did not specify the type or severity of the adverse event. AUTHORS' CONCLUSIONS: Participants in the NLT group experienced fewer hospital admissions for any cause and an increase in survival and number of participants reaching target dose within a shorter time period. However, the quality of evidence regarding the proportion of participants reaching target dose was low and should be interpreted with caution. We found high-quality evidence supporting NLT as one strategy that may improve the optimisation of beta-adrenergic blocking agents resulting in a reduction in hospital admissions. Despite evidence of a dose-dependent relationship of beta-adrenergic blocking agents, ACEIs, and ARBs with improving outcomes in patients with HFrEF, the translation of this evidence into clinical practice is poor. NLT is one strategy that facilitates the implementation of this evidence into practice.

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Os polímeros do tipo poli-hidroxialcanoatos (PHAs) são poliésteres bacterianos que apresentam as propriedades de termoplásticos e elastômeros biodegradáveis. A síntese deste polímero em plantas de interesse agroindustrial tem sido vista como uma área promissora dentro da biotecnologia de polímeros para a produção em grande escala com baixos custos. Contudo, esta tarefa requer o aprimoramento de diferentes metodologias bioquímicas e moleculares, além de maximizar os processos de extração destes polímeros biológicos. A produção de PHAs em peroxissomos ou no citoplasma de Saccharomyces cerevisiae, por meio da expressão de uma PHA-sintase bacteriana, pode servir como indicador e modulador do fluxo de carbonos que percorre vias biossintéticas como a síntese de novo de ácidos graxos e a β-oxidação. Esta levedura tem sido usada como eucarioto modelo para manipular as rotas envolvidas na síntese de PHAs do tipo MCL (PHA com um número médio de carbonos), um polímero menos cristalino e com menor ponto de fusão quando comparado ao PHA-SCL (PHA com um número pequeno de carbonos). A enzima PhaG (3-hidroxidecanoil-ACP-CoA transacilase) é responsável pela conexão entre a síntese de ácidos graxos e a produção de PHA-MCL em bactérias do gênero Pseudomonas, em meios de cultura contendo uma fonte de carbono nãorelacionada como gliconato, etanol ou acetato. Para tentar estabelecer esta rota metabólica em S. cerevisiae, o presente trabalho avaliou a coexpressão de PhaGPa e PhaC1Pa (PHA-sintase) de P. aeruginosa para a síntese de PHA-MCL a partir de uma fonte de carbono não-relacionada em leveduras. Contudo, a presença de PhaGPa não alterou a composição ou a quantidade de PHA-MCL em relação à cepa controle contendo apenas PhaC1Pa citoplasmática ou direcionada ao peroxissomo, independentemente da fonte de carbono utilizada (rafinose ou ácido oléico). Este resultado permite sugerir que a ligação entre a síntese de ácidos graxos e a produção de PHA-MCL em S. cerevisiae não foi estabelecida, provavelmente devido à ausência de algum passo enzimático que limita o desvio de substratos da síntese de ácidos graxos para a produção de PHA-MCL em organismos que não são capazes de acumular naturalmente este polímero quando cultivados em fontes de carbono não-relacionadas.A levedura S. cerevisiae tem sido usada como um sistema modelo para estudar a β-oxidação de ácidos graxos insaturados em peroxissomos. A produção de PHA-MCL pela expressão de PhaC1Pa em peroxissomos de cepas selvagens e mutantes nulos de S. cerevisiae para as enzimas auxiliares da β-oxidação (Eci1p, Sps19p e Dci1p), multiplicadas em meio de cultivo contendo um ácido graxo insaturado como fonte de carbono, permitiu monitorar o fluxo de carbonos que percorre as vias dependente de isomerase, redutase e di-isomerase. Desta forma, o presente estudo permitiu avaliar a β- oxidação in vivo dos ácidos graxos linoléico conjugado, 9-cis,11-trans-CLA (ácido rumênico) ou 10-cis,13-cis-nonadecadienóico, para determinar a contribuição das vias alternativas na degradação destes substratos pela utilização de cepas selvagens, mutantes nulos e linhagens contendo um plasmídio multicópia para os genes ECI1 (Δ3- Δ2-enoil-CoA isomerase), SPS19 (2,4-dienoil-CoA redutase) e DCI1 (Δ3,5-Δ2,4-dienoil- CoA isomerase). As linhagens selvagens foram capazes de sintetizar PHA-MCL quando cultivadas em ácido rumênico, mas a atividade da enzima Eci1p foi essencial para a degradação deste CLA, indicando que a via dependente de isomerase é a única rota in vivo necessária para a β-oxidação do ácido rumênico em peroxissomos de S. cerevisiae. A contribuição da enzima di-isomerase (Dci1p) para a degradação do ácido 10- cis,13-cis-nonadecadienóico foi avaliada em cepas selvagens, mutantes nulos dci1Δ e linhagens de S. cerevisiae contendo os plasmídeos multicópia. De acordo com o conteúdo e a quantidade de PHA formado, a β-oxidação de ácidos graxos cisinsaturados em um carbono ímpar é, in vivo, independente da di-isomerase. Embora este resultado possa indicar o mesmo padrão de envolvimento de Dci1p na degradação de ácidos graxos cis-insaturados em um carbono ímpar em mitocôndrias de mamíferos, esta via alternativa deve ser mais bem investigada em eucariotos superiores.

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SILVA, H.P.A.; SOUSA, M.B.C. The pair-bond formation and its role in the stimulation of reproductive function in female common marmosets (collithrix Jacchus). International Journal of Primatology, v, 18, n.3, p.387-400, 1997.

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To investigate the role of β-(1-3)-D-glucan on 99mTc labelled Escherichia coli translocation and cytokines secretion in rats submitted to small bowel ischemia/reperfusion injury. Methods: Five groups (n=10 each) of Wistar rats were subjected to control(C), sham(S), group IR subjected to 45 min of bowel ischemia/60 min of reperfusion(I/R), and group I/R+glucan subjected to 45 min of bowel ischemia/60 min of reperfusion(I/R) and injected with 2mg/Kg intramuscular. Translocation of labelled bacteria to mesenteric lymph nodes, liver, spleen, lung and serum was determined using radioactivity/count and colony forming units/g(CFU/g). Serum TNFα, IL-1β, IL-6, IL-10 were measured by ELISA. Results: CFU/g and radioactivity/count were higher in I/R than in I/R+glucan rats. In C, S and S+glucan groups, bacteria and radioactivity/count were rarely detected. The I/R+glucan rats had enhancement of IL-10 and suppressed production of serum TNFα, IL-1β and, IL-6, compared to I/R untreated animals. Conclusion: The β-(1-3)-D-glucan modulated the production of pro-inflammatory and anti-inflammatory cytokines during bowel ischemia/reperfusion, and attenuated translocation of labelled bacteria

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

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Ropivacaine (RVC) is an enantiomerically pure local anesthetic (LA) largely used in surgical procedures, which presents physico-chemical and therapeutic properties similar to those of bupivacaine (BPV), but associated to less systemic toxicity This study focuses on the development and pharmacological evaluation of a RVC in 2-hydroxypropyl-beta-cyclodextrin (HP-P-CD) inclusion complex. Phase-solubility diagrams allowed the determination of the association constant between RVC and HP-beta-CD (9.46 M-1) and showed an increase on RVC solubility upon complexation. Release kinetics revealed a decrease on RVC release rate and reduced hemolytic effects after complexation. (onset at 3.7 mM and 11.2 mM for RVC and RVCHP-beta-CD, respectively) were observed. Differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray analysis (X-ray) showed the formation and the morphology of the complex. Nuclear magnetic resonance (NMR) and job-plot experiments afforded data regarding inclusion complex stoichiometry (1:1) and topology. Sciatic nerve blockade studies showed that RVCHP-beta-CD was able to reduce the latency without increasing the duration of motor blockade, but prolonging the duration and intensity of the sensory blockade (p < 0.001) induced by the LA in mice. These results identify the RVCHP-beta-CD complex as an effective novel approach to enhance the pharmacological effects of RVC, presenting it as a promising new anesthetic formulation. (c) 2007 Elsevier B.V All rights reserved.

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