33 resultados para In-control

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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The properties of positively invariant sets are involved in many different problems in control theory, such as constrained control, robustness analysis, synthesis and optimization. In this paper we provide an overview of the literature concerning positively invariant sets and their application to the analysis and synthesis of control systems.

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It was studied that the nanostructure formed on a gold surface via a simple oxidation-reduction cycles (ORC) in 0.1 M KCl containing Ru(bpy)(3)(2+) with different concentrations. Atomic force microscopy (AFM) and energy-dispersed spectroscopy (EDS) were used to characterize the nanostructure formed on the gold surface. Sweep-step voltammetry and corresponding electroluminescence (ECL) response, in situ electrochemical quartz crystal microbalance (EQCM) measurement were used to monitor the ORC. procedure. It was found that the surface structure became more uniform in the presence of Ru(bpy)(3)(2+), and the surface roughness was decreasing with the increasing of Ru(bpY)(3)(2+) concentration, suggesting a simple and effective method to control the formation of nanostructure on the gold surface.

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BACKGROUND: Effects of 17beta-estradiol and progesterone on rhesus monkey oocyte maturation in vitro were evaluated by embryo development subsequent to IVF. METHODS AND RESULTS: In experiment 1, immature cumulus-oocyte complexes collected from unstimulated adult females during the non-breeding season were matured in modified medium CMRL-1066 containing various combinations of gonadotrophins (FSH + LH), estradiol and/or progesterone. Formation of morulae and blastocysts was greatest in oocytes matured in medium containing estradiol and/or progesterone, with or without gonadotrophins (morula 38-46%, blastocyst 14-20%) than in control oocytes matured without estradiol or progesterone (morula 14%, blastocyst 0%). In experiment 2, cumulus-oocyte complexes from unstimulated prepubertal female monkeys were matured in medium with gonadotrophins, estradiol or progesterone. The best development to the morula stage was obtained with oocytes matured with gonadotrophins and estradiol or gonadotrophins and progesterone (43 and 25 morulae, respectively), while control oocytes matured with gonadotrophins but without steroid hormones gave the poorest morula developmental response (12%). However, there was no difference in blastocyst development across all groups (0-3%). CONCLUSIONS: These results demonstrate that during rhesus monkey oocyte maturation in vitro: (i) estradiol or progesterone can improve oocyte developmental competence; (ii) immature oocytes from prepubertal versus adult females have differential responses to challenge with estradiol or progesterone.

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A highly active cobra venom factor (CVF) was isolated from the venom of Naja kaouthia by sequential column chromatography. It displays strong anticomplementary activity, and has 1515 U of anti complementary activity per mg protein. A single dose of 0.1 mg/kg CVF given i.v. to rats completely abrogated complement activity for nearly 5 days. Given 0.02 mg/kg of CVF. the complement activity of rats was reduced by more than 96.5% in 6 It. In guinea pig-to-rat heart transplant model, rats treated with a single dose of 0.05 mg/kg CVF had significantly prolonged xenograft survival (56.12 +/- 6.27 h in CVF-treated rats vs. 0.19 +/- 0.07 h in control rats, P < 0.001). (C) 2003 Elsevier Ltd. All rights reserved.

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The kinetics of mucosal and serum antibody response is well as antibody secreting cells (ASCs) production were studied in large yellow croaker following vaccination with inactivated Vibrio harveyi by different routes: oral administration. intraperitoneal (IP) injection and immersion. Indirect ELISA was used to measure the antibody level in serum and cutaneous mucus, and ELISPOT was used to monitor the ASCs derived from gill, blood and head kidney. The data demonstrated that IP injection resulted in the highest antibody levels in the systemic circulation, whereas immersion induced significant antibody levels in mucous. As for the ASCs response, IP injection induced high numbers of ASCs in the head kidney and blood; oral intubation only induced a slight ASCs response in the head kidney: immersion induced a much stronger ASCs response in the gill. These results indicate that mucosal antibodies following immersion immunization are independent of a systemic response and more sensitive, since it could be triggered earlier than serum antibodies. The mucosal antibodies following IP injection immunization may depend oil a systemic immune response. The protective effects of the three vaccination methods were compared by challenging with live V. harveyi. Survival of the three groups of vaccinated fish varied front 40 to 60%. while 100% mortality was found in control fish. Compared with IP and oral vaccination, immersion stimulated higher specific antibody titers in the mucosal system and achieved similar protection, so it is in effective and efficient method for immunizing a large number of fish against V harveyi (C) 2008 Elsevier B.V. All rights reserved.

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Crustacean zooplankton size structure in 27 aquaculture lakes was studied to test the hypothesis that larger size structure is associated with higher grazing pressure. Mean body length of crustaceans was positively correlated with increasing Chl a (r(2) = 0.40, P = 0.000) and TP (r(2) = 0.38, P = 0.000), contrary to the empirical studies. However, the ratio of zooplankton to phytoplankton biomass decreased significantly with increasing TP (r(2) = 0.27, P = 0.005) and mean body length (r(2) = 0.46, P = 0.000). Meanwhile, size structure showed no significant effect in explaining residual variations of phosphorus-chlorophyll relationship (P = 0.231). These results indicate that larger size structure was not always associated with higher zooplankton grazing pressure. It is likely that in aquaculture lakes crustacean zooplankton size structure was of minor importance in control of phytoplankton biomass, and it was mainly regulated by fish predation. The results showed in our study and the empirical studies might be a reflection of two different stages of lake eutrophication and fish predation intensity.

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The potential use of poultry by-product meal (PBM) and meat and bone meal (MBM) as alternative dietary protein sources for juvenile Macrobrachium nipponense was studied by a 70-day growth trial. Triplicate groups of M. nipponense (initial body weight: 0.37 g) were fed at 20.7-22.4 degreesC on each of the five isoenergetic and isonitrogenous diets (protein content about 38%) with different replacement of fish meal by MBM or PBM. The control diet used white fish meal as the sole protein source, the other four diets were prepared with 15% or 50% fish meal protein substituted by either MBM (MBM15, MBM50) or PBM (PBM15, PBM50). The results showed that replacement of fish meal by MBM in diets did not affect growth performance of M. nipponense (P > 0.05), while specific growth rate in PBM15 was significantly higher than that in other groups (P < 0.05). Survival rates of shrimp fed with MBM15 diet were significantly higher than that in other groups (P < 0.05). No significant differences in immunological parameters, including total haemocyte count (THC), phenoloxidase activity (PO) and respiratory burst (O-2(-)), were observed between the shrimps that were fed five experimental diets, and all determined immunological parameters in control groups were slightly higher than those in replacement groups. In conclusion, either MBM or PBM investigated could replace up to 50% fish meal protein in diets for M. nipponense. (C) 2003 Elsevier Ltd. All rights reserved.

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Increased oxidative stress induced by hyperglycemia may contribute to the pathogenesis of diabetic complications. Urinary 8-hydroxydeoxyguanosine (8-OHdG) has been reported to serve as a sensitive biomarker of oxidative DNA damage and also of oxidative stress. This article studied oxidative DNA damage in patients with diabetic nephropathy and in healthy control subjects by urinary 8-OHdG evaluations. Contents of 8-OHdG in urine were analyzed by capillary electrophoresis with end-column amperometric detection (CE-AD) after a single-step solid-phase extraction (SPE). Levels of urinary 8-OHdG in diabetic nephropathy patients with macroalbuminuria was significant higher than in control subjects (5.72 +/- 6.89 mumol/mol creatinine versus 2.33 +/- 2.83 mumol/mol creatinine, P = 0.018). A significant difference of 24 h urinary 8-OHdG excretions exists between the patients with macroalbuminuria and the patients with nonnoalbuminuria (19.2 +/- 16.8 mug/24 h versus 8.1 +/- 1.7 mug/24 h, P = 0.015). There was a positive correlation between urinary excretion of 8-OHdG and glycosylated hemoglobin (HbA(1)c) (r = 0.287, P = 0.022). A weak correlation exists between the levels of 8-OHdG and triglyceride (r = 0.230, P = 0.074). However, the urinary 8-OHdG contents are not correlated with blood pressure and total cholesterol. The increased excretion of urinary 8-OHdG is seen as indicating an increased systemic level of oxidative DNA damage in diabetic nephropathy patients. (C) 2004 Elsevier B.V. All rights reserved.

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Zirconocene catalyst was heterogenized inside an organosilane-modified montmorillonite (MMT) pretreated by calcination and acidization, for supported catalyst systems with well-spaced alpha-olefin polymerization active centers. The varied pretreatment and modification conditions of montmorillonite are efficient for supported zirconocene catalysts in control of polyethylene microstructures, in particular, molecular weight distribution. In contrast to other supported catalyst systems, Cp2ZrCl2/modified montmorillonite(MMT-7)-supported catalysts with a distinct interlayer structure catalyzed ethylene homopolymerization and copolymerization with I-octene activated by methylaluminoxane (MAO), resulting in polymers with a bimodal molecular weight distribution (MWD).

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Seed rearing is an important part in large scale clam culture industry. Since the nutritional history affects early development in bivalve, the condition of larval nutrition plays a key role in successful seed rearing. So far, the molecular mechanism of nutrient uptake in bivalve larvae is unclear. As one of the important proteolytic enzymes, cathepsin B of several organisms has been reported to be involved in digestion. We intended to analyze whether cathepsin B is involved in larval nutrient metabolism in the economic bivalve, clam Meretrix meretrix. The full length of M. meretrix cathepsin B (MmeCB) cDNA was cloned, which is 1647 bp with an open reading frame of 1014 bp. The deduced amino acid sequence encoded a preproenzyme of 337 residues with Cys-114, His-282 and Asn-302 composing cathepsin B activity center. The temporal and spatial expressions of MmeCB mRNA were examined from trochophore to post larva stages by whole mount in situ hybridization. In trochophore stage, no detectable signal was found. In the later three stages, MmeCB mRNA was detected in the digestive gland, suggesting a possible role of MmeCB in digestion. Moreover, MmeCB mRNA was also observed in the epidermal cells in D-veligers. Cathepsin B specific inhibitor (CA074 methyl ester) was applied to block the activity of cathepsin B in unfed larvae. The average shell lengths of treated larvae were smaller than that in control groups. The results of mRNA epidermal distribution and inhibitor treatment in D-veligers indicated that MmeCB may be also associated with other pathway of nutrient metabolism in larval epidermis. The overall results in this paper revealed that MmeCB might play a role in larval nutrient metabolism. (C) 2008 Elsevier B.V. All rights reserved.

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Grazing of dominant zooplankton copepods (Calanoides acutus. and Metridia gerlachei), salps (Salpa thompsoni) and microzooplankton was determined during the austral summer of 1998/1999 at the seasonal ice zone of the Prydz Bay region. The objective was to measure the ingestion rates of zooplankton at the seasonal ice zone, so as to evaluate the importance of different groups of zooplankton in their grazing impact on phytoplankton standing stock and primary production. Grazing by copepods was low, and accounted for less than or equal to 1% of phytoplankton standing stocks and 3.8-12.5% of primary production for both species during this study, even the ingestion rates of individuals were at a high level compared with previous reports. S. thompsoni exhibited a relatively high grazing impact on primary production (72%) in the north of our investigation area. The highest grazing impact on phytoplankton was exerted by microzooplankton during this investigation, and accounted for 10-65% of the standing stock of phytoplankton and 34-100% of potential daily primary production. We concluded that microzooplankton was the dominant phytoplankton consumer in this study area. Salps also played an important role in control of phytoplankton where swarming occurred. The grazing of copepods had a relatively small effect on phytoplankton biomass development.

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The present study was conducted to determine the effects of supplementary feeds, oat hay (OH), highland barley straw (HBS) and multi-nutrient blocks supplementation (UMMB) on reducing liveweight losses of both yak cows and calves grazed on low quality pastures during cold season. The trials of OH and HBS supplementation were conducted by using completely random design on 104 yak cows between 6 and 12 years of age as the following treatments: pure grazing (41 animals, body weight 230 67 kg) as control (CK); grazing+1.5 kg DM of OH per head daily (30 animals, body weight 216 28 kg); gazing. 1.5 kg DM of HBS per head daily (33 animals, body weight 221 34 kg). The trial of UMMB was conducted on three types of yaks, 1-year calves (8-12 months old, body weight 61.1 6.9 kg), 2-year calves (18-24 months old, 98.0 11.3 kg) and yak cows (164.5 27.1 (S.D.) kg) with 20 animals in control group (CK) and 20 animals in supplement group for each type by using completely random design as the following treatments: pure grazing for CK group; grazing+ 150, 250 and 500 g UMMB per day averagely for 1-year calf, 2-year calf and cow at night. The results indicate that the animals supplemented with oat hay received body weight gain (32 20.7 g day(-1)), while those supplemented with highland barley straw still suffered from body weight loss (-56.7 39.3 a day(-1)); UMMB supplementation can decrease the body weight loss by 109.7%, 86.6% and 63.4% for the 1-year calves, 2-year calves and yak cows, respectively, as compared with pure grazing. Around US$1.60 output can be achieved on the basis of US$1 input for UMMB supplementation in the farming systems of the 1-year calves, 2-year calves and yak cows, while US$1 input can produce US$1.55 and 1.14 output for OH and FIBS supplementations, respectively, in yak cows' farming system. It can be preliminary concluded that UMMB supplementation was the most economic way to alleviate body weight loss of grazing yaks over cold season, and the higher productive returns were obtained from OH supplementation for grazing yak cows during winter/spring months. © 2004 Elsevier B.V All rights reserved.

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Testosterone undecanoate (TU) is under phase III clinical trial as a hormonal male contraceptive in China. Sex hormones can modulate the immune system. Female hormonal contraceptives may affect SIV/HIV-1 transmission. To evaluate the safety of TU and to understand whether long-term use of TU for a male contraceptive affects users' immunological features, adult male rats were treated for a 32-week TU-treated phase at the dose of 20 mg TU/kg body weight and a 24-week recovery phase. The reproductive and immunological parameters of 4-6 rats in each subgroup were examined at the stated time point. The mean sperm count and viability in the treated rats were significantly suppressed (p < 0.01). In the TU-treated group: the mean blood leukocyte and lymphocyte counts; the proliferation indexes of T cells from peripheral blood mononuclear cells (PBMC) and spleen; and, of B cells from spleen, as well as the mean counts of blood T, NK, and B cells decreased in comparison with those of control group. These decreases were not significant (p > 0.01). Similarly, the mean serum IgM, IgG, and IgA levels and complement activity in TU-treated rats were lower than those in control group (p > 0.01), and the changes in the antibody levels of the examined genital secretions were not significant (p > 0.01). The changes in the thickness of urethra epithelium, and in secretory component (SC) expression in genitals were not observed in the treated group. These results demonstrated that long-term supraphysiological TU injection did not obviously affect the examined rat immunological parameters.

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In xenotransplantation, donor endothelium is the first target of immunological attack. Activation of the endothelial cell by preformed natural antibodies leads to platelet binding via the interaction of the glycoprotein (GP) Ib and von Willebrand factor (vWF). TMVA is a novel GPIb-binding protein purified from the venom of Trimeresurus mucrosquamatus. In this study, the inhibitory effect of TMVA on platelet aggregation in rats and the effect on discordant guinea pig-to-rat cardiac xenograft survival were investigated. Three doses (8, 20 or 40 mug/kg) of TMVA were infused intravenously to 30 rats respectively. Platelet aggregation rate was assayed 0.5, 12, and 24 h after TMVA administration. Wister rats underwent guinea pig cardiac cervical heterotopic transplantation using single dosing of TMVA (20 mug/kg, i.v., 0.5 h before reperfusion). Additionally, levels of TXB2 and 6-keto-PGF(1alpha) within rejected graft tissues were determined by radioimmunoassay. Treatment with TMVA at a dose of 20 or 40 mug/kg resulted in complete inhibition of platelet aggregation 0.5 h after TMVA administration. Rats receiving guinea pig cardiac xenografts after TMVA therapy had significantly prolonged xenograft survival. Histologic and immunopathologic analysis of cardiac xenografts in TMVA treatment group showed no intragraft platelet microthrombi formation and fibrin deposition. Additionally, the ratio of 6-keto-PGF(1alpha) to TXB2 in TMVA treatment group was significantly higher than those in control group. We conclude that the use of this novel GPIb-binding protein was very effective in preventing platelet microthrombi formation and fibrin deposition in a guinea pig-to-rat model and resulted in prolongation of xenograft survival. The increased ratio of PGI(2)/TXA(2) in TMVA treatment group may protect xenografts from the endothelial cell activation and contribute to the prolongation of xenograft survival.