论严遂成诗歌对浙派诗风的继承与超越

清代湖州诗人严遂成，在与厉鹗等浙派文人的结社交往中达成了观念、态度上的符契，受到浙派诗风的影响，部分诗歌继承了浙派“宗宋”“尚清”的诗风:在诗学倾向上，以宋诗为宗，师法杜甫、苏轼、黄庭坚等大家；在创作特色上，以学问为诗，写景咏物诗大多清新绮丽。由于丰富的游历经验和强烈的功业情结，严遂成的登临、怀古、咏史诗悲壮激烈、雄气纵横，具有“尚雄”的特殊风貌，显示了对浙派“尚清”诗风的超越。     

Evaluation and control of miRNA-like off-target repression for RNA interference

RNA interference (RNAi) has been widely adopted to repress specific gene expression and is easily achieved by designing small interfering RNAs (siRNAs) with perfect sequence complementarity to the intended target mRNAs. Although siRNAs direct Argonaute (Ago), a core component of the RNA-induced silencing complex (RISC), to recognize and silence target mRNAs, they also inevitably function as microRNAs (miRNAs) and suppress hundreds of off-targets. Such miRNA-like off-target repression is potentially detrimental, resulting in unwanted toxicity and phenotypes. Despite early recognition of the severity of miRNA-like off-target repression, this effect has often been overlooked because of difficulties in recognizing and avoiding off-targets. However, recent advances in genome-wide methods and knowledge of Ago–miRNA target interactions have set the stage for properly evaluating and controlling miRNA-like off-target repression. Here, we describe the intrinsic problems of miRNA-like off-target effects caused by canonical and noncanonical interactions. We particularly focus on various genome-wide approaches and chemical modifications for the evaluation and prevention of off-target repression to facilitate the use of RNAi with secured specificity.     

Intrinsic forces alone are sufficient to cause closure of the neural tube in the chick

Summary An isolated neural plate or a postnodal piece of early chick embryos, when cultured under appropriate experimental conditions, can undergo morphogenetic movements and form tubular structures closely resembling neural tubes of early chick embryos.This work was supported by grants from the NIH (NS 23200 and NS 21730) and the Busch Fund of Rutgers University.     

Optical monitoring of activity of many neurons in invertebrate ganglia during behaviors

Optical methods for monitoring neuron activity were developed because these methods lend themselves to simultaneous multiple-site measurements. With the use of new voltage-sensitive dyes, the dye-related pharmacology and photodynamic damage appear to be relatively unimportant. Using multiple-site measurements made with a 124-element photodiode array, we estimated that approximately 30 of the 200 neurons present in the Navanax buccal ganglion make action potentials during feeding and that approximately 300 of the 1100 neurons present in the Aplysia abdominal ganglion are active during the gill-withdrawal reflex. The fact that a light mechanical touch to the siphon skin activated such a large number of neurons in the abdominal ganglion suggests that understanding the neuronal basis of the gill-withdrawal reflex and its behavioral plasticity may be forbiddingly difficult.     

Comparison of classifications using measures intermediate between metric dissimilarity and consensus similarity

Two fundamental approaches to the comparison of classifications (e g, partitions on the same finite set of objects) can be distinguished One approach is based upon measures of metric dissimilarity while the other is based upon measures of similarity, or consensus These approaches are not necessarily simple complements of each other Instead, each captures different, limited views of comparison of two classifications The properties of these measures are clarified by their relationships to Day's complexity models and to association measures of numerical taxonomy The two approaches to comparison are equated with the use of separation and minimum value sensitive measures, suggesting the potential application of an intermediate sensitive measure to the problem of comparison of classifications Such a measure is a linear combination of separation sensitive and minimum value sensitive components The application of these intermediate measures is contrasted with the two extremes The intermediate measure for the comparison of classifications is applied to a problem of character weighting arising in the analysis of Australian stream basinsWe thank Bill Day, Mike Austin, Peter Minchin and two anonymous referees for many helpful comments We also thank P Arabie for useful discussion of consensus methods and character weighting     

Protection of substantia nigra from MPP+ neurotoxicity by N-methyl-D-aspartate antagonists.

Intake of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) leads to symptoms of Parkinson's disease and produces degeneration of nigrostriatal dopaminergic neurons in humans, giving rise to the hypothesis that this disorder may be caused by endogenous or environmental toxins. Excitation mediated by dicarboxylic amino acids such as L-glutamate or L-aspartate, has been claimed to be involved in pathogenesis of neurodegenerative disorders. We therefore sought to determine whether antagonists active at the NMDA or quisqualate subtypes of L-glutamate receptors prevent toxicity of either MPP+ (1-methyl-4-phenyl-pyridinium ion, the active metabolite of MPTP) or the selective dopaminergic neurotoxin 6-OHDA in the rat substantia nigra pars compacta. We report here that certain selective NMDA antagonists (AP7, CPP, MK-801), but not the preferential quisqualate antagonists CNQX and NBQX, provided short-term (up to 24 h) protection against MPP+ toxicity when coadministered into the substantia nigra. Systemic administration of CPP or MK-801 also offered temporary protection for up to 4 h against MPP+ toxicity. Repeated systemic administration of either compound prolonged protection against MPP+ challenge. Repeated administration for at least 24 h also led to permanent protection, still evident 7 days after intranigral administration of MPP+.     

Effects of PGE2 and PGF2 alpha on the simulation by noradrenaline and oxytocin of human cervical muscle activity at term

Cervical specimens were obtained by needle biopsy in connection with caesarean section at term pregnancy. The preparations were superfused in an organ chamber and contractions were registered isometrically. Prostaglandin (PG) E2 and F2 alpha inhibited spontaneous contractions. The stimulatory action of noradrenaline was not influenced by PGF2 alpha but was reduced by PGE2 whereas both PGs abolished the excitatory effect of oxytocin.     

Dopamine-beta-hydroxylase activity in adrenal gland and spleen of rats after fasting and cold exposure

Fasting (48 h) results in dopamine-beta-hydroxylase (DBH) release both in adrenal gland and spleen, suggestive of an increase in the activity of these organs. Cold exposure (48 h) produces a dissociation of the sympathoadrenal response. When both stimuli are simultaneously employed, the DBH response suggests the preponderance of the response to fasting. Plasma DBH is decreased in all groups studied, this could be due to its half-life and the splenic DBH depletion.     

An analysis of the distribution of the myelinated nerve fibers in the optic fascicle of a beagle dog

The composition of both optic fascicles of a Beagle dog was studied in topographically oriented, semithin transections of whole nerve stained with toluidine blue. About 165,000 myelinated fibers were present in each nerve, their maximum caliber reaching 11 micron; large, less densely arranged fibers occurred especially in the dorso-temporal region.     

Basic fibroblast growth factor prevents death of lesioned cholinergic neurons in vivo

Cutting the axons of the cholinergic neurons that project to the hippocampal formation results in death of most of these cells. Previous studies have shown that administration of nerve growth factor before or at the same time as the lesion will prevent this cell death. Here we demonstrate that basic fibroblast growth factor (FGF) administered into the brain reduces the death of cholinergic neurons in the medial septum and diagonal band of Broca after transection of their axons, in both young adult and aged rats. Moreover, FGF can partially protect against death of cholinergic neurons even when administered two days after axonal transection. These results indicate a possible function for FGF in the normal support of basal forebrain cholinergic neurons, but its range of activity could be wider, for FGF also supports noncholinergic neurons in vitro, it is localized in many of the central nervous system neurons, and it is found in relatively high concentrations in the brain.