山东小麦地方品种资源铁和锌含量分析

利用等离子体发射光谱仪,对426份山东小麦地方品种资源进行了铁和锌微量元素含量的测定,摸清了山东省小麦地方品种资源铁和锌含量的分布情况。结果表明,山东小麦地方品种资源铁含量的分布范围为5.2～44.1mg/kg,锌含量的分布范围为6.2～50.4mg/kg。铁含量最高的种质是土耳其和落麦,分别为44.1mg/kg和41.8mg/kg;锌含量最高的种质是大青芒,为50.4mg/kg。利用这些铁锌含量高、子粒商品性及面制品口味好的小麦地方品种作育种亲本,对培育子粒中富含铁锌微量元素的高营养小麦新种质,具有十分重要的意义。     

Age dependent sex allocation in the polygynous spotless starling

Theoretical and empirical evidence suggests that avian females are able to manipulate the offspring sex ratio at birth. Although mating with an attractive male may induce females to skew the sex ratio toward males, the balance between the benefits of producing attractive sons and the costs of competing with other females for mates could vary with female age, a possibility that had not been previously explored. In this paper we increment experimentally the attractiveness of males of the polygynous spotless starling (Sturnus unicolor) by adding green plants to their nests, a trait involved in courtship, and look for female age-differential effects on offspring primary sex ratio. Young and middle aged females produced more sons in experimental than in control nests, as expected, but old females showed the opposite tendency. To explain this novel result, we speculate that older females are limited to produce the most costly sex because the physiological drawbacks imposed by ageing reduce their ability to compete with younger ones for the non-shareable resources offered by males. We discuss that this evolutionary scenario may be widespread in avian polygynous systems.     

Material basis for inhibition of Dragon’s Blood on evoked discharges of wide dynamic range neurons in spinal dorsal horn of rats

In vivo experiments were designed to verify the analgesic effect of Dragon’s Blood and the material basis for this effect. Extracellular microelectrode recordings were used to observe the effects of Dragon’s Blood and various combinations of the three components (cochinchinenin A, cochinchinenin B, and loureirin B) extracted from Dragon’s Blood on the discharge activities of wide dynamic range (WDR) neurons in spinal dorsal horn (SDH) of intact male Wistar rats evoked by electric stimulation at sciatic nerve. When the Hill's coefficients describing the dose-response relations of drugs were dif-ferent, based on the concept of dose equivalence, the equations of additivity surfaces which can be applied to assess the interaction between three drugs were derived. Adopting the equations and Tal-larida's isobole equations used to assess the interaction between two drugs with dissimilar dose-response relations, the effects produced by various combinations of the three components in modulating the evoked discharge activities of WDR neurons were evaluated. Results showed that Dragon’s Blood and its three components could inhibit the evoked discharge frequencies of WDR neurons in a concentration-dependent way. The Hill's coefficients describing dose-response relations of three components were different. Only the combined effect of cochinchinenin A, cochinchinenin B and loureirin B was similar to that of Dragons Blood. Furthermore, the combined effect was synergistic. This investigation demonstrated that through the synergistic interaction of the three components Dragon’s Blood could interfere with the transmission and processing of pain signals in spinal dorsal horn. All these further proved that the combination of cochinchinenin A, cochinchinenin B, and loureirin B was the material basis for the analgesic effect of Dragon’s Blood.     

Bees get a head start on honey production

Nectar concentration is assumed to remain constant during transport by honeybees between flowers and hive. We sampled crop contents of nectar foragers on Aloe greatheadii var. davyana, a major winter bee plant in South Africa. The nectar is dilute (approx. 20% w/w), but the crop contents of bees captured on flowers are significantly more concentrated. In returning foragers, the concentration increases further to 38–40%, accompanied by a volume decrease. The doubling of sugar concentration suggests that nectar is regurgitated onto the tongue and evaporated during foraging and on the return flight. Processing of the dilute nectar into honey thus begins early, aided by low ambient humidities. This has implications for honeybee thermoregulation, water balance and energetics during foraging, and for the communication of nectar quality to recruits.     

Multiple sex chromosome system of X1X1X2X2/X1X2)Y type in lutjanid fish, Lutjanus quinquelineatus (Perciformes)

The karyotype and other chromosomal markers as revealed by C-banding and Ag-staining were studied in Lutjanus quinquelineatus and L. kasmira (Lutjanidae, Perciformes). While in latter species, the karyotype was invariably composed of 48 acrocentric chromosomes in both sexes, in L. quinquelineatus the female karyotype had exclusively 48 acrocentric chromosomes (2n = 48) but that of the male consisted of one large metacentric and 46 acrocentric chromosomes (2n = 47). The chromosomes in the first meiotic division in males showed 22 bivalents and one trivalent, which was formed by an end-to-end association and a chiasmatic association. Multiple sex chromosome system of X₁X₁X₂X₂/X₁X₂Y type resulting from single Robertsonian fusion between the original Y chromosome and an autosome was hypothesized to produce neo-Y sex chromosome. The multiple sex chromosome system of L. quinquelineatus appears to be at the early stage of the differentiation. The positive C-banded heterochromatin was situated exclusively in centromeric regions of all chromosomes in both species. Similarly, nucleolus organizer region sites were identified in the pericentromeric region of one middle-sized pair of chromosomes in both species. The cellular DNA contents were the same (3.3 pg) between the sexes and among this species and related species.     

Biosorption of copper by marine algae Gelidium and algal composite material in a packed bed column

Marine algae Gelidium and algal composite material were investigated for the continuous removal of Cu(II) from aqueous solution in a packed bed column. The biosorption behaviour was studied during one sorption–desorption cycle of Cu(II) in the flow through column fed with 50 and 25 mg l⁻¹ of Cu(II) in aqueous solution, at pH 5.3, leading to a maximum uptake capacity of ≈13 and 3 mg g⁻¹, respectively, for algae Gelidium and composite material. The breakthrough time decreases as the inlet copper concentration increases, for the same flow rate. The pH of the effluent decreases over the breakthrough time of copper ions, which indicates that ion exchange is one of the mechanisms involved in the biosorption process. Temperature has little influence on the metal uptake capacity and the increase of the ionic strength reduces the sorption capacity, decreasing the breakthrough time. Desorption using 0.1 M HNO₃ solution was 100% effective. After two consecutive sorption–desorption cycles no changes in the uptake capacity of the composite material were observed. A mass transfer model including film and intraparticle resistances, and the equilibrium relationship, for adsorption and desorption, was successfully applied for the simulation of the biosorption column performance.     

偶联剂在生物涂层中的应用

综述了生物材料的研究及问题,论述了偶联剂的种类及其作用机理,在此基础上介绍了偶联剂的研究现状与应用概况。重点论述了偶联剂在生物涂层中的应用及其前景。     

Comparative Risk Assessment Methods and Their Applicability to Dredged Material Management Decision-Making

This article reviews the status of comparative risk assessment within the context of environmental decision-making; evaluates its potential application as a decision-making framework for selecting alternative technologies for dredged material management; and makes recommendations for implementing such a framework. One of the most important points from this review for decision-making is that comparative risk assessment, however conducted, is an inherently subjective, value-laden process. There is some objection to this lack of total scientific objectivity (“hard version” of comparative risk assessment). However, the “hard versions” provide little help in suggesting a method that surmounts the psychology of choice in decision-making schemes. The application of comparative risk assessment in the decision-making process at dredged material management facilities will have an element of value and professional judgment in the process. The literature suggests that the best way to incorporate this subjectivity and still maintain a defensible comparative framework is to develop a method that is logically consistent and allows for uncertainty by comparing risks on the basis of more than one set of criteria, more than one set of categories, and more than one set of experts. It should incorporate a probabilistic approach where necessary and possible, based on management goals.     

Seasonal and spatial variation in the diet of brown trout (Salmo trutta L.) in the subarctic River Laxá, north-east Iceland

This study examines seasonal and spatial patterns in the diet composition, stomach fullness and condition of a landlocked population of brown trout (2.5–61.3 cm) in the lake-fed River Laxá in NE-Iceland. The stomach contents consisted predominantly of benthic invertebrates, such as blackfly larvae Simulium vittatum (58%), chironomids (24%) and the freshwater snail Radix peregra (7%). The seasonal and spatial patterns of S. vittatum in the stomach contents were consistent with published studies on the life cycle and production of S. vittatum in the River Laxá. Close to the Lake Myvatn outlet (0–16 km), S. vittatum constituted 63% of the stomach content volume, and exhibited two peaks (i.e., generations) in its seasonal contribution to the stomach contents, whereas further downstream (16–35 km) S. vittatum constituted 45% of the volume and showed only clear evidence of one generation. Seasonal fluctuations in S. vittatum availability appear to affect the stomach fullness and the condition factor of the trout, especially close to the lake outlet where the fluctuations are pronounced.     

不同烤瓷牙内冠材料对产生龈缘黑线影响的分析

目的：分析镍铬合金,金合金材料制作烤瓷内冠以及镍铬合金内冠涂制金粉对冠修复后产生龈缘黑线的影响。方法：对3052例烤瓷冠病例,分别用镍铬合金,金合金制作内冠以及运用金粉涂制镍铬合金内冠进行修复,经一年以上随访。对上述三种材料对产生龈缘黑线状况进行评价。结果：采用金合金制作内冠及对镍铬合金内冠粉制金涂制作烤瓷冠未产生龈缘黑线,而单纯用镍铬合金制作内冠,可能产生龈缘黑线。结论：镍铬合金烤瓷内冠不可避免会产生龈缘黑线,金合金烤瓷内冠避免了上述缺点,而镍铬合金内冠涂制金粉则是一条经济,实效的制作工艺。