Changes in erythrocyte deformability in NaCl-induced right-sided cardiac failure in broiler chickens.

In this study, we tested the hypothesis that erythrocyte deformability is decreased in the development of cardiac failure induced by NaCl toxicosis. Deformability of erythrocytes and routine hematologic and biochemical variables were measured in 6 of 50 chickens that were given 5 g of NaCl/L in their drinking water from day 7 to day 42, and were compared with values in 6 of 50 healthy chickens given free access to tap water. Deformability was assessed by passing a 10% suspension of erythrocytes through a polycarbonate membrane with 5-microns pores. Chickens were euthanatized and heart and body weights were determined. Treatment with NaCl induced right-sided cardiac failure up to day 28. The ratios of heart weight to body weight were greater, for right ventricle by 20 to 64% and for left ventricle by 15 to 27%, attributable to NaCl treatment. Deformability of erythrocytes of NaCl-treated chickens was markedly decreased, in association with increased erythrocyte size and plasma Na+ concentration. However, only part of the decreased deformability could be explained by swelling of erythrocytes. Decreased deformability could not be explained by increased cell viscosity because mean corpuscular hemoglobin concentration, the primary determinant of erythrocyte viscosity, was decreased. Because decreased deformability of erythrocytes has been demonstrated previously to be associated with increased vascular resistance, decreased deformability may have contributed to the development of right-sided cardiac failure in these chickens.     

Blood oxygen concentration of fast-growing and slow-growing broiler chickens, and chickens with ascites from right ventricular failure.

Percent hemoglobin oxygen saturation was measured with a pulse oximeter in 6-week-old slow-growing (light) and fast-growing (heavy) male broiler chickens and those with ascites from right ventricular failure (RVF). Pulse rate and percent oxygen saturation were read from the ulnar artery just proximal to the carpus. Percent oxygen saturation was significantly (P less than or equal to 0.0001) higher in light chickens (mean 91.6%) than in heavy chickens (mean 86.0%), and the percent oxygen saturation was significantly (P less than or equal to 0.0001) higher in both groups with normal hearts than in the group with RVF from valvular insufficiency (mean 62.1%). All RVF chickens and those with normal hearts were confirmed at necropsy. Light chickens were males with leg deformity or stunting and were 20-50% lighter than the heavy chickens.     

菜蛾绒茧蜂生物学研究

菜蛾绒茧蜂(Apanteles plutellae Kurbjumov)是小菜蛾(plutella xylo-stella L.)幼虫非群栖性的寄生蜂。在杭州室内条件下,每年发生15代。以预蛹越冬。除越冬代外,发育历期与日平均温度的回归式为Y=52.4-1.5x±2.4(天)产卵期最长17天。能寄生各龄小菜蛾幼虫,但以2～3龄为宜。每雌最大有效子蜂数235头,日出茧量最高38头。周年雌雄性比1:0.8。孤雌生殖后代纯为雄蜂。田间最高自然寄生率59.4％。莱蛾啮小蜂(Tetrastichus sokol-owskii)是最重要的重寄生物,又是小菜蛾幼虫到蛹的寄生蜂。     

Bedrock fracture by ice segregation in cold regions

The volumetric expansion of freezing pore water is widely assumed to be a major cause of rock fracture in cold humid regions. Data from experiments simulating natural freezing regimes indicate that bedrock fracture results instead from ice segregation. Fracture depth and timing are also numerically simulated by coupling heat and mass transfer with a fracture model. The depth and geometry of fractures match those in Arctic permafrost and ice-age weathering profiles. This agreement supports a conceptual model in which ice segregation in near-surface permafrost leads progressively to rock fracture and heave, whereas permafrost degradation leads episodically to melt of segregated ice and rock settlement.     

Influence of exogenous ethylene during refrigerated storage on storability and quality of Actinidia chinensis (cv. Hort16A)

The kiwifruit industry was established on fruit of Actinidia deliciosa (‘Hayward’), which is known as a climacteric fruit with high sensitivity to ethylene. In recent times fruit from Actinidia chinensis have become a substantial component of the kiwifruit market. There is limited information about the sensitivity of A. chinensis to ethylene during refrigerated storage and hence current ethylene management practices for A. chinensis mimic those established for A. deliciosa. This research aimed to quantify the effect of ethylene during refrigerated storage on A. chinensis (‘Hort16A’) quality (firmness, colour and total soluble solids). Three grower lines were stored at 1.5 °C, 95% RH with ethylene in the range of 0.001-1 μL L⁻¹ applied to the environment after 3 weeks of storage for the remainder of storage (17 weeks). Fruit quality was assessed at regular intervals. Loss of firmness was found to be very sensitive to ethylene, with significant differences between fruit stored in 0.001 μL L⁻¹ (as a control) and 0.1 μL L⁻¹ occurring after 2 weeks of exposure. Fruit exposed to 1 μL L⁻¹ ethylene not only rapidly softened, but also increased in hue angle (greenness) and reduced in lightness (darkened) further reducing the quality of the yellow coloured kiwifruit cultivar. Total soluble solids were not heavily influenced by ethylene exposure, with grower differences being maintained throughout the experiment. This work demonstrates that A. chinensis (cv. Hort16A) fruit firmness and colour will be influenced by the ethylene conditions in a commercial storage environment by advancing ripening and senescence.     

Dipolar antiferromagnetism and quantum criticality in LiErF₄

Magnetism has been predicted to occur in systems in which dipolar interactions dominate exchange. We present neutron scattering, specific heat, and magnetic susceptibility data for LiErF(4), establishing it as a model dipolar-coupled antiferromagnet with planar spin-anisotropy and a quantum phase transition in applied field H(c|| = 4.0 ± 0.1 kilo-oersteds. We discovered non-mean-field critical scaling for the classical phase transition at the antiferromagnetic transition temperature that is consistent with the two-dimensional XY/h(4) universality class; in accord with this, the quantum phase transition at H(c) exhibits three-dimensional classical behavior. The effective dimensional reduction may be a consequence of the intrinsic frustrated nature of the dipolar interaction, which strengthens the role of fluctuations.