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The nucleation site of austenite from pearlitic structure during reverse transformation at 1073K in Fe–0.6C–1Cr (mass%) alloy was examined by means of electron backscattering diffraction. It was found that austenite preferentially nucleates at high-angle boundaries (HABs) of pearlitic ferrite. Some austenite nuclei maintain a near Kurdjumov–Sachs (K–S) orientation relationship (OR) with one or two pearlitic ferrites adjacent to the HAB. Austenite nucleated at the HAB face preferentially grows into the adjacent pearlitic ferrite, deviating greatly from the K–S OR. [Copyright &y& Elsevier]

Abstract: The effects of addition of Si, Mn and Cr on the kinetics of reverse transformation at 1073K from the spheroidized cementite structure obtained by heavy tempering of high carbon martensite are investigated. The rate for reverse transformation is the fastest in the Fe–0.6 mass% C binary material, and becomes slower with the addition of Mn, Si and Cr. In particular, the retarding effect of Cr addition is remarkable, and holding times orders of magnitude longer than for other alloys are necessary to complete the reverse transformation. Based on thermodynamics and TEM/EDS analyses, it is supposed that austenite growth is controlled by carbon diffusion in specimens with Si and Mn added, as well as the Fe–0.6 mass% C binary material, while a decrease in the carbon activity gradient with the addition of these elements results in slower reversion kinetics. However, in the Cr-added specimen, Cr diffusion is necessary for austenite growth, yielding extremely sluggish reaction kinetics. [Copyright &y& Elsevier]

Abstract: In this Letter we study the superfluid–Mott-insulator (SMI) phase transition of two-component Bose–Einstein condensates (BECs) in an optical lattice. The analytic exciation energy spectrum is obtained by means of Bogoliubov transformation and hence the SMI phase transition condition is determined explicitly. Moreover, the characteristics of superfluid phase are explained from the energy spectrum. [Copyright &y& Elsevier]

The response of Peking ducks to supplements of Sophy β-glucan was studied. A total of 160 healthy 1-d-old mixed-sex ducklings were randomly allocated to 3 groups:.Sophy β-glucan (n = 80), bacitracm zinc (n = 40), and control (n = 40), which received the same antibiotics-deficient diet supplemented with 1% β-glucan, 5% bacitracin zinc, or nothing, respectively. During 2 mo of the study, growth performance, carcass composition, and meat quality of Peking ducks were evaluated. Additionally, a separate immunological study was conducted with a total of 105 healthy male Peking ducks in 7 groups (n = 15) and immunized with different doses of β-glucan (0, 0.5, 2.5, 12.5, and 62.5 μg/duck) and BSA (200 μg/duck). Blood was taken for detection of anti-BSA-IgG antibody and peripheral blood mononuclear cells proliferation assays. Groups subjected to different dietary treatments showed almost no differences in growth performance and slaughter traits except breast muscle percentage and intestinal length. These 2 indicators were significantly higher in the bacitracin zinc group than in the control and β-glucan groups (P < 0.05). Similarly, chemical compositions, fatty acids, and amino acids of breast muscle were not significantly influenced by the diet. Ducks immunized with Sophy β-glucan did not have enhanced level of anti-BSA-IgG antibodies but had significant peripheral blood mononuclear cells proliferation compared with unchallenged ducks (P < 0.01). With an increase in the glucan concentration, the proliferative responses approximately linearly increased. These findings indicate that 1% Sophy glucan did not improve duck growth performance, carcass composition, and meat quality significantly under the conditions of the present experiment and mainly had regulatory or enhancing properties on poultry nonspecific cellular immunity. [ABSTRACT FROM AUTHOR]

Earlier experimental data in our laboratory showed that introduction of an exogenous protein into early chicken embryonic blood leads to immunotolerance of hatched chicken to that protein. However, the underlying mechanism is yet unknown. In the present study, we show that the blood cells collecting circulating antigen might contribute to the establishment of immunotolerance. In this experiment, most of the chicken embryo blood cells took up injected fluorescein isothiocyanate-BSA at approximately embryonic d 3. At the same stage, 1μL of embryo blood was taken out and incubated with BSA. After being loaded with BSA in vitro and washed, these cells were injected back into the original embryo. The BSA-specific lymphocytes were depleted in chickens whose early embryo cells had been loaded with BSA, as evidenced by a significant decrease in anti-BSA antibody after challenge with BSA when the chickens were 3 wk old. In addition, by direct injection of BSA to embryonic d 3 embryo blood, the hatched chickens had decreased amounts of anti-trinjtrophenol antibody after the chickens were challenged with trinitrophenol-BSA, indicating that the helper function of BSA-specific T cells was impaired. In conclusion, these observations suggest that some early embryo blood cells possibly collect and store antigen for the establishment of self-tolerance before the maturation of B and T cells. [ABSTRACT FROM AUTHOR]

Ovarian cortical tissues of various ages of chicken were grafted underneath chorioallantoic membrane (CAM) of 6-d-old chicken embryo and the grafts were collected on d 0, 2, 4, 8, or 10. The tissue sections were prepared to examine the development of follicles in grafts and the proliferative ability of follicles was examined by immunohistochemistry analysis of proliferating cell nuclear antigen. The results indicated that the development of follicles in cultured chicken ovarian cortical pieces progressed smoothly and slowly similar to those in vivo, and the environment of chicken embryo was more suitable for the synchronous development of oocyte and follicular cells in the larger follicles. Meanwhile, the synchronous development could be more easily achieved in the chicken ovarian tissues of 12- to 15-wk chicken. Neither oocyte nor granulosa cells but the thecal cells of follicles developed in grafts of 13- to 15-d chicken within 10 d of culturing in ovo, and the CAM can ease follicular atresia in chicken ovarian grafts of 12- to 15-wk chicken. The proliferative performance of follicles in the grafts was not influenced by the environment of chicken embryo. These results indicated that the chicken embryo has the ability to support slow development of primordial and primary follicles in grafted ovarian cortical tissues of chickens of different ages. The CAM system may also prove useful for the study of early follicle development with further information. [ABSTRACT FROM AUTHOR]