TiO2/α-Fe2O3复合光催化剂的制备及表征

用溶胶-凝胶法在α-FeOOH上负载TiO2,经过煅烧制备了TiO2/α-Fe2O3光催化剂.用Brunauer-Emmett-Teller(BET)法测试氮吸附比表面积.用X射线衍射、透射电镜、扫描电镜、Fourier转换红外光谱等研究了不同煅烧温度制备的光催化剂物相组成和形貌特征.研究了不同煅烧温度制备的光催化剂对活性艳蓝X-BR染料的吸附和光催化性能.结果表明:与未负载TiO2的α-FeOOH相比,经过复合、350℃煅烧制备的TiO2/α-Fe2O3复合材料的比表面积有了显著增加,从35.4m2/g增加到167.7m2/g,但是,当温度高于450℃时,其比表面积又有所下降.随着煅烧温度的增加,其负载的TiO2晶型由锐钛矿转变为金红石型,粒径也逐渐增大.在煅烧温度为350℃时,TiO2/α-Fe2O3催化剂吸附和光催化性能最好,脱色率可达到85.19%.     

Sympathetic response to stimulation of the pontine A5 region in conscious rabbits

OBJECT: This study is a retrospective analysis of clinical data obtained in 28 patients affected by obstructive hydrocephalus who presented with signs of midbrain dysfunction during episodes of shunt malfunction. METHODS: All patients presented with an upward gaze palsy, sometimes associated with other signs of oculomotor dysfunction. In seven cases the ocular signs remained isolated and resolved rapidly after shunt revision. In 21 cases the ocular signs were variably associated with other clinical manifestations such as pyramidal and extrapyramidal deficits, memory disturbances, mutism, or alterations in consciousness. Resolution of these symptoms after shunt revision was usually slow. In four cases a transient paradoxical aggravation was observed at the time of shunt revision. In 11 cases ventriculocistemostomy allowed resolution of the symptoms and withdrawal of the shunt. Simultaneous supratentorial and infratentorial intracranial pressure recordings performed in seven of the patients showed a pressure gradient between the supratentorial and infratentorial compartments, with a higher supratentorial pressure before shunt revision. Inversion of this pressure gradient was observed after shunt revision and resolution of the gradient was observed in one case after third ventriculostomy. In six recent cases, a focal midbrain hyperintensity was evidenced on T2-weighted magnetic resonance imaging sequences at the time of shunt malfunction. This rapidly resolved after the patient underwent third ventriculostomy. CONCLUSIONS: It is probable that in obstructive hydrocephalus, at the time of shunt malfunction, the development of a transtentorial pressure gradient could initially induce a functional impairment of the upper midbrain, inducing upward gaze palsy. The persistence of the gradient could lead to a global dysfunction of the upper midbrain. Third ventriculostomy contributes to equalization of cerebrospinal fluid pressure across the tentorium by restoring free communication between the infratentorial and supratentorial compartments, resulting in resolution of the patient's clinical symptoms.     

Reconceptualizing feeding and feeding disorders in interpersonal context: The case for a relational disorder.

The feeding of young children is fundamentally a relational and multisystemic process. Successful treatment of clinically significant feeding problems involves careful assessment of the full range of influences on the feeding relationship and integrated treatment approaches. However, current diagnostic approaches to feeding disorders tend to be reductionistic, exclusively focused on the child as an individual, and overly concerned with exclusionary criteria. Criteria are proposed for "Feeding Disorder Between Parent and Child" that address these limitations and embrace the complexity of feeding problems. A multiaxial diagnosis that describes the child (including medical, developmental, and behavioral characteristics); the parent; the parent-child relationship; and the social and nutritional context of feeding will more accurately speak to treatment planning in this population. The proposed diagnostic criteria were developed and refined on the basis of the available literature and many years of treatment experience across the authors of this article. The proposed diagnosis will support the development and evaluation of treatment packages with components specifically targeted to issues of the child, parent, parent-child interaction, and the broader environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spontaneous orientation of transplanted olfactory glia influences axonal regeneration

Transplanted olfactory ensheathing cells (OECs) have previously been demonstrated to support axonal growth and myelination in the adult rat CNS. Here, the capacity of donor OECs to control the direction of axonal regeneration has been investigated following transplantation, as elongated columns, into the thalamus of adult rats. The OECs formed a 'glial bridge' which extended from the thalamus to the hippocampus. Transplanted OECs rapidly adopted a spindle-shaped morphology which was orientated along the vertical axis of the transplant. Numerous host axons grew into the transplants and followed the highly orientated OEC cell matrix across the choroid fissure. Thus, the spontaneous elongation and orientation of donor OECs may support highly directional host axonal growth across natural barriers within the CNS.     

Meta-analysis of multiple outcomes by regression with random effects

Earlier work showed how to perform fixed-effects meta-analysis of studies or trials when each provides results on more than one outcome per patient and these multiple outcomes are correlated. That fixed-effects generalized-least-squares approach analyzes the multiple outcomes jointly within a single model, and it can include covariates, such as duration of therapy or quality of trial, that may explain observed heterogeneity of results among the trials. Sometimes the covariates explain all the heterogeneity, and the fixed-effects regression model is appropriate. However, unexplained heterogeneity may often remain, even after taking into account known or suspected covariates. Because fixed-effects models do not make allowance for this remaining unexplained heterogeneity, the potential exists for bias in estimated coefficients, standard errors and p-values. We propose two random-effects approaches for the regression meta-analysis of multiple correlated outcomes. We compare their use with fixed-effects models and with separate-outcomes models in a meta-analysis of periodontal clinical trials. A simulation study shows the advantages of the random-effects approach. These methods also facilitate meta-analysis of trials that compare more than two treatments.     

GLUT4 and transferrin receptor are differentially sorted along the endocytic pathway in CHO cells

The trafficking of GLUT4, a facilitative glucose transporter, is examined in transfected CHO cells. In previous work, we expressed GLUT4 in neuroendocrine cells and fibroblasts and found that it was targeted to a population of small vesicles slightly larger than synaptic vesicles (Herman, G.A, F. Bonzelius, A.M. Cieutat, and R.B. Kelly. 1994. Proc. Natl. Acad. Sci. USA. 91: 12750-12754.). In this study, we demonstrate that at 37 degrees C, GLUT4-containing small vesicles (GSVs) are detected after cell surface radiolabeling of GLUT4 whereas uptake of radioiodinated human transferrin does not show appreciable accumulation within these small vesicles. Immunofluorescence microscopy experiments show that at 37 degrees C, cell surface-labeled GLUT4 as well as transferrin is internalized into peripheral and perinuclear structures. At 15 degrees C, endocytosis of GLUT4 continues to occur at a slowed rate, but whereas fluorescently labeled GLUT4 is seen to accumulate within large peripheral endosomes, no perinuclear structures are labeled, and no radiolabeled GSVs are detectable. Shifting cells to 37 degrees C after accumulating labeled GLUT4 at 15 degrees C results in the reappearance of GLUT4 in perinuclear structures and GSV reformation. Cytosol acidification or treatment with hypertonic media containing sucrose prevents the exit of GLUT4 from peripheral endosomes as well as GSV formation, suggesting that coat proteins may be involved in the endocytic trafficking of GLUT4. In contrast, at 15 degrees C, transferrin continues to traffic to perinuclear structures and overall labels structures similar in distribution to those observed at 37 degrees C. Furthermore, treatment with hypertonic media has no apparent effect on transferrin trafficking from peripheral endosomes. Double-labeling experiments after the internalization of both transferrin and surface-labeled GLUT4 show that GLUT4 accumulates within peripheral compartments that exclude the transferrin receptor (TfR) at both 15 degrees and 37 degrees C. Thus, GLUT4 is sorted differently from the transferrin receptor as evidenced by the targeting of each protein to distinct early endosomal compartments and by the formation of GSVs. These results suggest that the sorting of GLUT4 from TfR may occur primarily at the level of the plasma membrane into distinct endosomes and that the organization of the endocytic system in CHO cells more closely resembles that of neuroendocrine cells than previously appreciated.     

Characterisation of erythrocyte shapes and sizes by NMR diffusion-diffraction of water: correlations with electron micrographs

Irradiation of the mammalian foetus produces a broad spectrum of congenital abnormalities, growth retardations, developmental delays, and functional deficits, depending upon the dose and the specific gestational phase of irradiation. The developing brain is particularly susceptible to production of deleterious effects, with decreased brain size, behavioural alterations, and mental retardation having been documented. Supplementing the limited human data, rodent models have been extensively used to investigate the specific processes by which relatively low doses, with correspondingly minor cellular damage to the developing neocortex, can produce dramatic postnatal consequences in brain structure and function. The effects of a variety of physical (dose, linear energy transfer, dose rate, fractionation) and biological (species, strain, gestational age, time course post-irradiation) parameters have been examined in an attempt to provide much needed information on such critical aspects as dose response, threshold doses for effect, and extrapolation to human risk estimates. Various acute cellular responses (e.g. appearance of pyknotic cells and macrophages) observed in the developing neocortex 0-24 h after in utero irradiation can be associated with postnatal effects. Moreover, it is possible to correlate thinning of specific layers of the cerebral cortex with specific behavioural aberrations, allowing prediction of brain structural changes from functional alterations, and vice versa. Thus, it is possible to speculate as to the mechanisms and targets for extremely sensitive, radiation-induced cellular damage in the developing foetal brain, that will interfere with the orderly and precisely programmed development of the mammalian brain, leading finally to postnatal expression as delays in growth and development, perturbations in behaviour, and alterations in brain structure.     

Methyl tert-butyl ether (MTBE) contamination in private wells near gasoline stations in upstate New York

BACKGROUND: Auxiliary liver transplantation has several advantages over standard orthotopic liver transplantation. However, functional competition has been reported even in auxiliary partial orthotopic liver transplantation (APOLT). We evaluated herein the interaction in APOLT between the native liver and the graft in terms of portal blood flow and regeneration. The need for diversion of the portal blood flow to the graft was also assessed. METHODS: A total of 15 patients received APOLT from living donors. Portal blood flow to the native liver was preserved in 6 patients, and the portal vein to the native liver was preemptively transected at the time of transplantation in 9 patients. RESULTS: Of the patients with preservation of the portal blood flow to the native liver, two showed inadequate graft portal blood flow just after operation, and in the other three patients the graft portal blood flow decreased or the graft atrophied after deterioration of the graft function. In the patients with preemptive transection of the portal vein to the native liver, optimal graft portal blood flow was obtained, and the native liver, supplied only by arterial inflow, supported a small-for-size graft until the graft regenerated. The damage to the native liver was minimal. CONCLUSIONS: Functional competition may occur in APOLT with preservation of the portal blood flow to the native liver, whereas preemptive transection of the native liver portal vein is a safe procedure and effectively prevents the portal steal phenomenon.