中生菌素及其在绿色食品生产中的应用

通过对中生菌素的有效组分、作用机理及安全性分析及4年的多点试验、示范,证明中生菌素能有效防治水稻白叶枯病、大白菜软腐病、苹果轮纹病等细菌性、真菌性病害,是生产绿色食品的理想药剂之一.     

Energy needs versus environmental pollution: a reconciliation?

In this article I have presented, for discussion, a proposed system for energy generation by which the principal sources of environmental pollution by power plants could be eliminated. For stationary power plants the concept appears feasible technically and, according to my " horseback estimates," perhaps economically as well, depending upon the economic value of the by-products of sulfur, CO(2), water, and possibly nitrogen, and upon the price we are willing to pay for a clean environment .Thus, a more thorough engineering and economic analysis to explore these and other factors in greater depth seems warranted. In the case of turbine-driven vehicles, the technical and economic feasibility of widespread distribution and handling of the fuel constitutes a serious question, but one which deserves equally serious consideration before the possibility is discounted. The reports of the cited study panels notwithstanding, the technology required for the proposed system exists today, with one exception. This exception (which is not essential for trial of the system but will be required for its complete fruition) is the development of a nuclear reactor for the prime purpose of delivering process heat for the steam reforming of natural gas and, ultimately, for gas production from coal in a continuous process, such as those discussed by Pieroni et al. (16). Today's intermittent processes of coking and gas production are both archaic and themselves large sources of atmospheric pollution, and a development program aimed at advancing the technology of the coal industry in this regard would seem long overdue. The report of the PSAC Environmental Pollution Panel recommended "demonstration of the feasibility and economy of new developments for abating or controlling pollution through their use at Federal installations" and suggested the coalburning TVA power plants as a likely place for such demonstration. This suggestion is doubly appropriate since the TVA is in a region of subnormal " atmospheric ventilation" (8). By design these plants are adjacent to the AEC's Oak Ridge National Laboratory, and such a location would seem ideal for an experiment on the wedding of nuclear and fossil sources of energy. In comments on a preliminary draft of this article, proponents of "conventional " nuclear power pointed out that such power is hard to beat on the basis of cost, and that dissipation of heat to the air by way of cooling towers can also be accomplished in conventional plants (17). These observations are individually correct but not compatible: the low power costs cited are for very large plants [of the order of 1000 mega-watts lectrical) and larger], and the costs of cooling towers and associated equipment needed to dissipate such large amounts of heat [of the order of 2000 megawatts (thermal)] to air from a closed cycle would offset the power cost advantage of the large plant. In regard to the proposed use of nuclear process heat, Weinberg (20) has expressed doubt that much advantage can be derived from this approach because the temperatures involved are too high for low-cost reactors, and heat transfer from surfaces could involve materials problems. In the case of gas production, this is indeed an anticipated problem-not a technologically insuperable one, but a problem of reducing the cost of the materials required (16). Indeed, Weinberg himself has mentioned this possible use of nuclear heat in a recent publication discussing the steam reforming of coal to liquid fuel(21). Also, an improved process for synthesizing methane from lignitec has recently been reported (22). Since the earlier studies date back a decade, a new look at the problems and costs involved relative to the benefits to be derived (not the least of which could be new vigor for the coal industry) would seem to be in order. In the case of steam reforming of natural gas, the temperature level (about 1500 degrees F) is such that the technology is available today, and a process-heat-reactor design study could be initiated without awaiting further developments.     

Quartz: extreme preferred orientation produced by annealing

Annealing of samples of flint under high pressure, after hot-working in the beta-quartz stability field, produced an exceedingly strong concentration of c-axes parallel to the direction of compression. A specimen deformed under identical conditions, but not annealed, exhibited a much weaker orientation. The strength of the annealed orientation rivals that of the remarkable "cube texture" produced by annealing some face-centered cubic metals after extreme reduction by rolling.     

Vasopressin and oxytocin excite distinct neuronal populations in the central amygdala

Vasopressin and oxytocin strongly modulate autonomic fear responses, through mechanisms that are still unclear. We describe how these neuropeptides excite distinct neuronal populations in the central amygdala, which provides the major output of the amygdaloid complex to the autonomic nervous system. We identified these two neuronal populations as part of an inhibitory network, through which vasopressin and oxytocin modulate the integration of excitatory information from the basolateral amygdala and cerebral cortex in opposite manners. Through this network, the expression and endogenous activation of vasopressin and oxytocin receptors may regulate the autonomic expression of fear.     

The design and catalytic properties of a simplified ribonuclease P RNA

Ribonuclease P (RNase P) RNA is the catalytic moiety of the ribonucleoprotein enzyme that removes precursor sequences from the 5' ends of pre-transfer RNAs in eubacteria. Phylogenetic variation according to recently proposed secondary structure models was used to identify structural elements of the RNase P RNA that are dispensable for catalysis. A simplified RNase P RNA that consists only of evolutionarily conserved features was designed, synthesized, and characterized. Although the simplified RNA (Min 1 RNA) is only 263 nucleotides in length, in contrast to the 354 to 417 nucleotides of naturally occurring RNase P RNAs, its specificity of pre-tRNA cleavage is identical to that of the native enzymes. Moreover, the catalytic efficiencies of the Min 1 RNA and the native RNA enzymes are similar. These results focus the search for the catalytic elements of RNase P RNAs to their conserved structure.     

Mixed leukocyte stimulation of normal peripheral leukocytes by autologous lymphoblastoid cells

Lymphocyte culture lines can be established by using buffy coat cells from normal or diseased individuals. Established lymphocytoblasts from a normal donor were used in the one-way mixed leukocyte culture test and were found to stimulate the peripheral lymphocytes of that donor. These lymphocytoblasts were also capable of stimulating allogeneic lymphocyte populations.     

Energized configurations of heart mitochondria in situ

Changes in the configurational state of the cristal membranes of rat heart mitochondria within the living cell can be induced by imposing energizing conditions. An exact correlation has been established between the configurational states of the cristal membrane and the energy states of the mitochondrion. The configurational changes observed in mitochondria in situ are comparable to those established for beef heart mitochondria in vitro and are consistent with the postulate of the conformational basis of energy transductions in membrane systems. The formation of paracrystalline arrays is one of the noteworthy features of configurational changes of mitochondria in situ.