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91.
Growing body of evidence points to dysregulation of redox status in the brain as an important factor in the pathogenesis of schizophrenia. The aim of our study was to evaluate the effects of l-buthionine-(S,R)-sulfoximine (BSO), a glutathione (GSH) synthesis inhibitor, and 1-[2-Bis(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazine dihydrochloride (GBR 12909), a dopamine reuptake inhibitor, given alone or in combination, to Sprague–Dawley pups during early postnatal development (p5–p16), on the time course of the onset of schizophrenia-like behaviors, and on the expression of brain-derived neurotrophic factor (BDNF) mRNA and its protein in the prefrontal cortex (PFC) and hippocampus (HIP) during adulthood. BSO administered alone decreased the levels of BDNF mRNA and its protein both in the PFC and HIP. Treatment with the combination of BSO + GBR 12909 also decreased BDNF mRNA and its protein in the PFC, but in the HIP, only the level of BDNF protein was decreased. Schizophrenia-like behaviors in rats were assessed at three time points of adolescence (p30, p42–p44, p60–p62) and in early adulthood (p90–p92) using the social interaction test, novel object recognition test, and open field test. Social and cognitive deficits first appeared in the middle adolescence stage and continued to occur into adulthood, both in rats treated with BSO alone or with the BSO + GBR 12909 combination. Behavior corresponding to positive symptoms in humans occurred in the middle adolescence period, only in rats treated with BSO + GBR 12909. Only in the latter group, amphetamine exacerbated the existing positive symptoms in adulthood. Our data show that rats receiving the BSO + GBR 12909 combination in the early postnatal life reproduced virtually all symptoms observed in patients with schizophrenia and, therefore, can be considered a valuable neurodevelopmental model of this disease.  相似文献   
92.

Speed control of a DC motor has always been a challenge because of its variable torque. But it becomes more challenging when noise enters the system at its input. Therefore, there is a need of more advanced controllers. In this paper, a multi-resolution proportional integral derivative (MRPID) controller has been proposed to be utilized to control the speed of a DC motor. It works well even in the presence of noise as compared to the conventional PID controller. Also, performance of a PID controller deteriorates when nonlinearity or uncertainty arises in the system. This degraded performance can be improved by utilizing the multi-resolution property of wavelets, which decomposes the error signal into various frequency components. Further, wavelet coefficients of these decompositions are used to generate the control signal for controlling speed of a DC motor. In this paper, performances of a MRPID, a fractional order PID (FOPID) and a conventional PID controllers are compared in the presence of noise for speed control of a DC motor. The results obtained using a MRPID controller are observed to be better in terms of improved transient characteristics and disturbance rejection for a DC motor as compared to those obtained with PID and FOPID controllers.

  相似文献   
93.
Articular cartilage dysfunctions are major cause of pain and disability and lead to serious health complications. Cell-based therapies are proposed as treatment methods for cartilage regeneration. In this study, we proposed polyurethane/poly(L-lactide-co-D, L-lactide)-based electrospun nonwovens as carriers for the delivery of human adipose-derived stromal stem cells. We found that 6:4 and 8:2 polyurethane/poly(L-lactide-co-D, L-lactide) initially enhance proliferative rate of human adipose-derived stromal stem cells, shorten their population doubling time, promote creation of functional chondrogenic nodules during chondrogenic differentiation, improve the collagen-2-to-collagen-1 protein ratio, and upregulate the expression of collagen-2 and aggrecan genes.  相似文献   
94.
Monika Goikoetxea 《Polymer》2010,51(23):5313-5317
Grafting of alkyd resin to the acrylic polymer is needed to fully exploit the possibilities of these hybrids; but in the current technology, grafting is accompanied by an important reduction of the unsaturated groups of the alkyds, which adversely affects the curing of the film and its properties. A novel strategy that overcomes these limitations is presented. The strategy is based on the use of alkyd resin functionalized with methacrylic groups, that substantially improved the incorporation of the resin to the growing acrylic polymer chain, and the polymer particle homogeneity, without decreasing the degree of unsaturation in the alkyd resin.  相似文献   
95.
Redox-active films have been generated via electrochemical reduction in a solution containing palladium(II) acetate and [C60]fullerene, or derivatives of C60. The C60 derivatives include piperazine (piperazine-C60), pyrrolidine (CH3-pyr-C60), and a pyrrolidine salt, [(CH3)2-pyr-C60]+ attached to the fullerene unit. In these films, fullerene moieties are covalently bonded to palladium atoms to form a polymeric network. The polymer yields involving the piperazine and pyrrolidine derivatives of C60 are significantly lower than the yield of the C60/Pd film. The CH3-pyr-C60/Pd and [(CH3)2-pyr-C60]+/Pd films are electrochemically active in the negative potential region due to the reduction of the fullerene moiety. Reduction of the CH3-pyr-C60/Pd film is accompanied by the transport of supporting electrolyte cations from the solution into the film. In the first reduction step of the [(CH3)2-pyr-C60]+/Pd film, both cations and anions of the supporting electrolyte are involved. The piperazine-C60/Pd film exhibits electrochemical activity at both negative and positive potentials. In the negative potential region, reduction of the fullerene cage takes place. Oxidation of the piperazine moiety is responsible for the observed current in the positive potential range. Here, the oxidation process of this polymer is significantly influenced by the presence of metallic palladium particles in the film.  相似文献   
96.
Energy games belong to a class of turn-based two-player infinite-duration games played on a weighted directed graph. It is one of the rare and intriguing combinatorial problems that lie in NPco-NP, but are not known to be in P. The existence of polynomial-time algorithms has been a major open problem for decades and apart from pseudopolynomial algorithms there is no algorithm that solves any non-trivial subclass in polynomial time. In this paper, we give several results based on the weight structures of the graph. First, we identify a notion of penalty and present a polynomial-time algorithm when the penalty is large. Our algorithm is the first polynomial-time algorithm on a large class of weighted graphs. It includes several worst-case instances on which previous algorithms, such as value iteration and random facet algorithms, require at least sub-exponential time. Our main technique is developing the first non-trivial approximation algorithm and showing how to convert it to an exact algorithm. Moreover, we show that in a practical case in verification where weights are clustered around a constant number of values, the energy game problem can be solved in polynomial time. We also show that the problem is still as hard as in general when the clique-width is bounded or the graph is strongly ergodic, suggesting that restricting the graph structure does not necessarily help.  相似文献   
97.
98.
FTIR reflection spectroscopy was used to characterize thin films of a cyanurate prepolymer on evaporated aluminium and on silicon single crystal wafers. Both substrates are covered by their native oxides. The optical function of the prepolymer is derived from ATR measurements. The measured thin film reflectance spectra have to be interpreted in comparison with the corresponding bulk spectra obtained by simulation. All samples re-produce the bulk composition. The cyanate groups of the prepolymer are not involved in specific intermolecular interactions or in preferential orientation. This is also found for the triazine rings on Si. On Al, however, a considerable excess of triazine rings are oriented parallel to the interface. The vibration frequencies of the triazine groupings that are perpendicular to the Al substrate show a red shift to some 2–8 c?1. This special interaction effect does not occur on Si. Both the preferential orientation and the specific inter-molecular interaction act at least 100 nm into the prepolymer layer.  相似文献   
99.
Biotransformation of ten α-haloacetophenones in the growing culture of the strain Rhodotorula rubra KCh 82 has been carried out. Nine of the substrates underwent an effective enantioselective reduction to the respective (R)-alcohols according to Prelog’s rule, with the exception of 2-chloro-1,2-diphenylethan-1-one that was not transformed by this strain. The expected reduction proceeded without dehalogenation, leading to the respective (R)-halohydrins in high yields. The use of this biocatalyst yielded (R)-2-bromo-1-phenyl-ethan-1-ol (enantiomeric excess (ee) = 97%) and its derivatives: 4''-Bromo- (ee = 99%); 4''-Chloro- (ee > 99%); 4''-Methoxy- (ee = 96%); 3''-Methoxy- (ee = 93%); 2''-Methoxy- (ee = 98%). There were also obtained and characterized 2,4''-dichloro-, 2,2'',4''-trichloro- and 2-chloro-4''-fluoro-phenyetan-1-ol with >99% of enantiomeric excesses.  相似文献   
100.
Chitosan–silver nanocomposites (CS-HDA-AgNCs) was prepared using chitosan, biogenic silver nanocomposites, and crosslinker, hexamethylene 1,6-di(amino carboxysulfonate) (HDA). The film is flexible and transparent. Its physical, mechanical, thermal, hydrophilicity, and swelling properties were improved by HDA (2.5%). The antimicrobial activity of CS-HDA-AgNCs were not displayed any remarkable zone of inhibition but showed toxic effect in the presence of normal 3T3 fibroblasts and cancer HeLa cells. It decreases to ca. 5–7% for both cell lines. In conclusion, it can be mentioned that the CS-HDA-AgNCs, a kind of new functional biomaterial, could be useful for health-care applications.  相似文献   
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