Effect of crossing a line selected for increased shank width with two commercial sire lines on performance and walking ability of turkeys

Published research indicated that a line (FL) of turkeys selected for increased shank width and exhibiting good walking ability (WA) and improved leg structure was useful in improving WA of a cross with an unimproved commercial sire line while remaining competitive in BW and body conformation. The purpose of the present study was to determine whether the FL line was useful in improving WA of two improved commercial primary-breeding sire lines and to study the inheritance of BW traits in the pure lines and reciprocal crosses of the pure lines. Samples of a primary breeding sire line from each of two major commercial turkey breeders were obtained as unpedigreed eggs and designated as Lines A and B. Lines A and B were reciprocally crossed with the FL line that had been selected for increased shank width for 16 generations. Pure lines and reciprocal crosses were produced by artificially mating 10 males to 15 females using pooled semen. The same semen pools were used to produce both the pure lines and the crosses. Traits measured included BW at 8, 16, and 20 wk of age, and length, width, and depth of the shank, width of the breast, and WA at 16 wk of age. The A and B lines were larger and had wider breasts and narrower and shorter shanks than the FL line. Line B was larger than Line A. Shank measurements and WA score did not differ between Lines A and B in either sex. Breasts of Line B females were wider than those of Line A females, but there was no sire line difference in breast width of males. Heterosis in BW was greater in Line A crosses (average of 4.6% with a range of 2.5 to 7.2% for BW at different ages) than in Line B crosses (average of 2.2% with a range of 0.1 to 5.3%). Heterosis in WA score was negative (crosses had better WA than pure lines) for males [14% for the Line A and FL crosses (P < or = 0.001) and 4% for the Line B and FL crosses (P < or = 0.05)], but was positive and nonsignificant for females of the above crosses (average of 2.6 %). With one exception, heterosis was not an important source of variation for shank width or shank depth and there was a low level of heterosis for shank length. No heterosis was observed for breast width. Reciprocal effects were an important source of variation in BW and shank measurements for females but not for males in both sets of crosses. The results of the present study indicated that use of the FL line to improve WA of improved primary-breeding commercial sire lines was not a feasible alternative. The slight improvement noted in WA of the male crosses was offset by the reduction in BW and breast width of the crosses relative to the pure commercial sire lines.     

On the Stress-Induced Formation of R-Phase in Ultra-Fine-Grained Ni-Rich NiTi Shape Memory Alloys

Phase transformations in binary ultra-fine-grained (UFG) pseudoelastic NiTi wires were studied in a wide temperature range using mechanical loading/unloading experiments, resistance measurements, differential scanning calorimetry (DSC), thermal infrared imaging, and transmission electron microscopy (TEM). The formation of R-phase can be detected in the mechanical experiments. It is shown that the stress-strain response of the R-phase can be isolated from the overall stress-strain data. The R-phase always forms prior to B19′ when good pseudoelastic properties are observed. The stress-induced B2 to R-phase transition occurs in a homogeneous manner, contrary to the localized character of the B2/R to B19′ transformations. The temperature dependence of the critical stress values for the formation of the martensitic phases shows a Clausius Clapeyron type of behavior with constants close to 6 MPa/K (B19′) and 18 MPa/K (R-phase). A stress-temperature map is suggested that summarizes the experimentally observed sequences of elementary transformation/deformation processes.     

Deformation of NiTiCu shape memory single crystals in compression

Single-crystal orientations of NiTi10Cu alloys were studied under incremental, cyclic compression conditions to establish the pseudoelastic and shape memory response of this class of alloys. This material exhibits a two-step transformation involving cubic to orthorhombic martensite (B2 → B19) followed by orthorhombic to monoclinic martensite (B19 → B19′). The transformation parameters (shear magnitudes and directions for habit and twin planes) were determined associated with the B2 → B19 transformation. The growth of monoclinic martensite correspondent variant pairs (CVPs) emanating from the orthorhombic structure was also analyzed. The transformation strain for the B2 → B19 case was orientation dependent and lower than the B19 → B19′ transformation in compression for all orientations except those near the [001] pole. The experimental results show that the critical transformation stress is orientation dependent and is in the range 30 to 58 MPa. Orientations that exhibit lower transformation stress (or high resolved shear stress factors, [100] and [012]) produce higher recoverable strains (as high as 4 pct), while other orientations ([011], [111], and [123]) with lower resolved shear stress factors result in recoverable strains less than 3 pct. At higher strains, inelastic deformation develops, limiting recoverability. The recoverable strains are lower than the theoretical values for two main reasons: the transformation is curtailed first by austenite slip and subsequently by martensite slip, and the orthorhombic structure does not fully transform to the monoclinic martensite.     

回火温度对渗碳钢18Cr2Ni4WA组织和硬度的影响

为满足用户加工HBW硬度值≤269的需要,降低18Cr2Ni4WA钢Φ60 mm材硬度,利用连轧厂实际辊底式退火炉进行了630～750℃5h炉冷至500℃空冷的回火试验,并借助金相显微镜对18Cr2Ni4WA钢不同回火温度下的组织进行了分析,以确定最佳的回火温度。结果表明,18Cr2Ni4WA钢随回火温度的升高硬度先下降后上升,当温度为670℃时,钢材平均HBW硬度值最低(HBW238左右),回火组织为均匀的回火珠光体组织。     

Representational aspects of word imageability and word frequency as assessed through word association.

Assessed the effects of word imageability and word frequency (WF) in word association (WA). Exps 1 and 2 employed the discrete WA task, whereas Exp 3 used the continued WA task. Data from Exps 1–3 showed that word imageability strongly determines responding in WA, whereas WF hardly affects it. Exp 4 (lexical decision) and 5 (word naming) explored the possibility that WF effects on the word-recognition stage in WA might have interfered with any effect of WF on the association-retrieval stage, a possibility that was not borne out by data. Exps 6–8 examined whether the absence of frequency effects on WA in Exps 1–3 might have been due to the fact that the WF classes had a restricted range. A new set of stimulus materials was constructed, with frequency classes further apart. Some small effects of this variable on WA were found. Results point out that the concept nodes for high-imageability words contain more information than those of low-imageability words and that relatively strong links depart fron the former type of nodes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

18Cr2Ni4WA钢组织与性能关系

本文通过对18Cr2Ni4WA钢的组织分析;讨论了组织与性能的关系,提出了断裂模型及获取最佳强韧化组织的工艺措施。     

High temperature creep in a semi-coherent NiAl-Ni2AlTi alloy

Creep experiments have been made on a Ni-Ti-Al alloy, which has a microstructure consisting of a distribution of semi-coherent NiAl(β) precipitates with a Ni₂AlTi(β′) Heusler phase matrix. The creep strength of this bcc type structure alloy is at least comparable with that of the nickel-base superailoy MARM-200 for values ofT/T _m in the range 0.68 to 0.82. Quantitative electron microscope experiments show that both undissociated α₀〈110〉 dislocations, and paired α₀〈100〉 dislocations coupled by a sublattice A.P.B. exist within the β′ phase;α ₀ is the lattice parameter of a bcc cell of which the large Ni₂AlTi unit-cell is composed. The sublattice A.P.B. is a crystallographic fault created by wrong bonds between atoms on the Al-Ti sublattice. Theoretically the energy γ of a sublattice A.P.B. is shown to be minimum on {100}, and the experimental value for γ on {100} is ~40 mJ/m₂.     

Comparison of precipitates between excess Si-type and balanced-type Al-Mg-Si alloys during continuous heating

Differential scanning calorimetry (DSC) curves were obtained from Al-1.0 mass pct Mg₂Si (balanced) and Al-1.0 mass pct Mg₂Si −0.4 mass pct Si (excess Si) alloys, and precipitates corresponding to each peak at the DSC curve were interpreted by means of high-resolution transmission electron microscopy (HRTEM) observation in order to understand the precipitation sequence of metastable phases. Five peaks were obtained on the DSC curves, from which four were exothermic (A, C, D, and E) and one endothermic (B). Upon HRTEM observation, the peaks for the excess Si alloy were explained as follows: peak A–B: Guinier-Preston (GP) zones and random-type precipitates; peak B: dissolution of the GP zones and the random-type precipitates, precipitation of the β″ phase; peak C: β″ phase and precipitation of type B; peak D: dissolution of the β″ phase; precipitation of type A and β′ phase; and peak E: dissolution of the type B, type A, and β′ precipitation of the (β+Si) phase. This result is quite different from that in the balanced alloy as follows: peak A–B: GP zones and random-type precipitates; peak B: dissolution of the GP zones and the random-type precipitates, precipitation of the parallelogram-type precipitate; peak C: parallelogram-type precipitate and precipitation of β′ phase; peak D: β′ phase, dissolution of parallelogram-type precipitate; and peak E: the β-(Mg₂Si).     

Calmodulin regulation of Ca2+ entry in Jurkat T cells

BACKGROUND: The authors have previously demonstrated abnormalities in glucose and insulin metabolism in nondiabetic black American (BA) adults versus white American (WA) adults. Whether similar glucoregulatory alterations extend to BA adolescents remain unknown. In addition, obesity, a known risk factor for insulin resistance and hyperinsulinemia, occurs in a greater proportion of BA adults and children when compared to WA. The objective of the present study was to examine the differential effects of obesity on glucose homeostasis in BA and WA adolescents. METHODS: We examined glucose homeostasis in BA and WA adolescents using oral glucose tolerance test (OGTT), intravenous glucose tolerance test (IVGTT), and [6,6-2H2]-glucose infusion. The study consisted of four age-, sex-, and pubertal stage-matched groups: 15 lean BA, 29 lean WA, 7 obese BA, and 9 obese WA. RESULTS: Both obese groups had significantly increased insulin and C-peptide area under the curve (AUC) during OGTT and IVGTT when compared to their same-race lean counterparts. During OGTT, obese BA demonstrated greater insulin and C-peptide when compared to obese WA. During IVGTT, first- and second-phase insulin were significantly greater in obese BA versus obese WA. CONCLUSION: In summary, BA adolescents demonstrated insulin resistance which is markedly exaggerated in the face of obesity when compared to WA adolescents, implying a differential impact for obesity on glucose homeostasis that is unique to the obese BA adolescent group. In conclusion, there is a need for early aggressive weight management in obese BA adolescents.     

Deformation behavior of a Ni3Al(B,Zr) alloy during cold rolling: Part I. changes in order and structure

A hypostoichiometric Ni₃Al(B,Zr) alloy was homogenized and cold rolled by amounts ranging from 25 to 73 pct. The alloy consisted of two phases—a partially ordered γ′ phase (L1₂) and a Ni-rich fcc solid solution (γ). On deforming the alloy by rolling at room temperature, the order parameter showed a gradual change. In fact, between 35 and 45 pct deformation, the order characteristic of the L1₂ structure changed into that of a DO₂₂ structure. The possibility of transition from L1₂ to DO₂₂ structure is also corroborated from strain parameter, microhardness, and detailed x-ray diffraction (XRD) measurements. This structural transformation is accompanied by a change in the deformation mode (from slip to twinning), as is evident from the relevant microstructures.     

<Emphasis Type="Italic">In-Situ</Emphasis> Synchrotron Characterization of Transformation Sequences in TiNi-Based Shape Memory Alloys during Thermal Cycling

In-situ synchrotron radiation has been used to provide direct analysis of the transformation sequences in TiNi-based shape memory alloys during thermal cycling. The high resolution, narrow peak width Debye–Scherrer diffraction spectra enabled positive identification and quantification of the phase transformation sequences, which is not possible through normal laboratory studies. The results facilitate a clearer understanding of the development and influence of intermediate phases such as R or B19 on sequential martensitic transformations. Ti_50.2Ni_49.8 transformed predominately via a single-step B2 ↔ B19′ transformation, although evidence of the R phase was found during cooling in every cycle. The martensitic start temperature was depressed by ~0.6 °C per cycle, while the R-phase start temperature was found to be unaffected. Ti₅₀Ni₄₁Cu₉ transformed through a two-step B2 ↔ B19 ↔ B19′ sequence, with the B2 → B19 transformation reaching completion prior to the formation of any B19′. The transformation temperatures of Ti₅₀Ni₄₁Cu₉ were found to be insensitive to thermal cycling, remaining constant over the studied cycle range.     

Microstructural characterization of Ni3Al processed by reactive atomization and deposition

Reactive atomization and deposition (RAD) is a new processing technique that has been developed to synthesize dispersion-strengthened materials. In this process, atomization,in situ reaction, and consolidation are combined into a single step by spray atomization and deposition with a reactive gas. The matrix material selected for this study is an Ni₃Al + Y + B alloy in combination with N₂-O₂ atomization gas. The as-deposited microstructures reveal a spheroidal grain morphology, a banded structure, and a γ + γ′ mosaiclike structure. The formation of the γ + γ′ mosaiclike structure is attributed to an annealing effect during deposition. Matrix-lattice mismatches of 0.5 to 1 pct at the γ/γ′ interface and {100} growth orientations of γ′ phase are deduced from microscopic observations. The formation of the banded structure is attributed to the high cooling rate that is inherent to RAD processing. Anticipated dispersoids, such as Y₂O₃, Al₂O₃, and Y₃Al₅O₁₂ are identified using transmission electron microscopy (TEM). Dislocation pileups and grain boundary pinning are observed in the vicinity of oxide dispersoids. The origin and movement of dislocations in the as-deposited materials may be attributed to the residual stresses that originate from thermal gradients and the large amount of deformation experienced by the solid and semisolid droplets during impact. The preliminary results and analyses reported here suggest that the high thermal stability of the RAD processed Ni₃Al using N₂-15 pct O₂ may be attributed not only to the hindering effect of oxide dispersoids on grain boundary mi-gration, but also to the high cooling rate experienced by the droplets during atomization and the short annealing effect experienced by the material during deposition.     

Modification of bone marrow radiosensensitivity by medicinal plant extracts

Withaferin A (WA), a steroidal lactone, and Plumbagin (Pl), a naphthoquinone, from the roots of Withania somnifera and Plumbago rosea, respectively, have been shown to possess growth inhibitory and radiosensitizing effects on experimental mouse tumours. An aqueous extract of the leaves of Ocimum sanctum (OE) was found to protect mice against radiation lethality. Therefore, the radiomodifying effects of the above plant products on the bone marrow of the adult Swiss mouse was studied. Single doses of WA (30 mg kg-1) or Pl (5 mg kg-1) were injected intraperitoneally (ip) and OE (10 mg kg-1) was injected ip once daily for five consecutive days. Administration of extracts was followed by 2 Gy whole body gamma irradiation. Bone marrow stem cell survival was studied by an exogenous spleen colony unit (CFU-S) assay. The effects of WA and Pl were compared with that of cyclophosphamide (CP) and radioprotection by OE was compared with that of WR-2721 (WR). Radiation reduced the CFU-S to less than 50% of normal. WA, CP and Pl significantly enhanced this effect and reduced the CFU-S to almost the same extent (to < 20% of normal), although individually WA and Pl were less cytotoxic than CP. These results indicate that radiosensitization by WA and Pl is not tumour specific. OE significantly increased CFU-S compared with radiotherapy (RT) alone. OE+RT gave a higher stem cell survival (p < 0.05) than that produced by WR+RT. While WR alone had a toxic effect, OE treatment showed no such effect, suggesting that the latter may have an advantage over WR in clinical application.     

Damping characteristics of Ti50Ni49.5Fe0.5 and Ti50Ni40Cu10 ternary shape memory alloys

The damping characteristics of Ti₅₀Ni_49.5Fe_0.5 and Ti₅₀Ni₄₀Cu₁₀ ternary shape memory alloys (SMAs) have been systematically studied by resonant-bar testing and internal friction (IF) measurement. The damping capacities of the B19′ martensite and the B2 parent phase for these ternary alloys are higher than those for the Ti₅₀Ni₅₀ binary alloy. The lower yield stress and shear modulus of these ternary alloys are considered to be responsible for their higher damping capacity. For the same ternary alloy, the B19/B19′ martensite and R phase also have a higher damping capacity than does the B2 parent phase. In the forward transformations of B2 → R, R → 519′, and B2 → 519′ for Ti₅₀Ni₅₀ and Ti₅₀Ni_49.5Fe_0.5 alloys, the damping capacity peaks appearing in the resonant-bar test are attributed to both stress-induced transformation and stress-induced twin accommodation. The lattice-softening phenomenon can promote the stress-induced transformation and enhance the damping capacity peaks. The Ti₅₀Ni₄₀Cu₁₀ alloy had an unusually high plateau of damping capacity in the B19 martensite, which is considered to have arisen from the easy movement of twin boundaries of B19 martensite due to its inherently very low elastic modulus. The peaks appearing in the IF test for the Ti₅₀Ni₄₀Cu₁₀ alloy are mainly attributed to the thermal-induced transformation due to T ⊋ 0 during the test.     

Control of ordered structure and ductility of (Fe,Co, Ni)3V alloys

This study is directed toward improvement of the ductility of long-range ordered alloys through control of their ordered crystal structure. A series of ordered alloys was prepared with a base composition of Co₃V, where Co was partially replaced with Fe and Ni. The stability and structure of the ordered phases in these (Fe,Co,Ni)₃V alloys were characterized by various metallurgical methods. The results indicate that the ordered structure in this alloy system can be controlled by adjusting the electron density, and that the L1₂ type cubic ordered structure (α′) is stable in the alloys with electron density less than 7.888. The phase relation in the cubic ordered alloys depends on the Fe concentration. For the alloys containing <20 pct Fe, the disordered α solid solution transforms to the cubic α′ ordered on the fcc lattice at temperatures below 1000°C. For the alloys containing >20 pct Fe, the α′ is formed through a peritectoid reaction, namely, α+σ→α′. Tensile tests indicate that the alloys with multilayered hexagonal ordered structure are very brittle, while the alloys with the cubic ordered structure are ductile at room temperature. The ductility of the cubic ordered alloys increases with decreasing Co content. The alloys with <55 pct Co showed dimple type ductile rupture with elongation over 40 pct at room temperature. The correlation of ductility with ordered structure is discussed.     

粉末特性对30CrMnSiNi2A钢组织和性能的影响

采用水雾化（water atomization,WA）、气雾化（gas atomization,GA）和等离子旋转电极雾化（plasma rotating electrode process,PREP）方式制备30CrMnSiNi2A钢粉,对比分析了不同雾化粉末的特征及其烧结体的组织与性能。结果表明:不同雾化粉末的形貌、粒度分布、氧含量及流动性等特征均存在一定差异,其中水雾化和气雾化粉末中存在空心粉和卫星粉,等离子旋转电极雾化粉末无内部缺陷,具有优异流动性,且氧含量最低。三种雾化粉末的烧结样品组织均为粒状贝氏体,但呈现出不同的原始颗粒边界形貌,随粉末氧含量的降低,原始颗粒边界处夹杂物尺寸减小,成分由富Al氧化物变为富Al、Si氧化物。相比于水雾化和气雾化粉末,等离子旋转电极雾化粉末的烧结样品拉伸性能最优,其拉伸强度和伸长率分别为1310 MPa和11.5%,这得益于良好的粉末质量和低的氧含量。     

Structure of phases in the δ-AI2O3 fiber studied by convergent beam electron diffraction

The phases in the δ-Al₂O₃ fibers were investigated using the methods of transmission electron microscopy (TEM): convergent beam electron diffraction (CBED) and high-resolution electron microscopy (HREM). A phaseγ′-Al₂O₃ discovered previously by Vewerly in oxide layers with an fcc structure was found and new atomic positions are proposed. A new structure ofδ-Al₂O₃ was also observed. It has aPmma space group and lattice parameters ofa _δ = 2a _γ′,b _δ = l.5a _γ′, andc _δ ≈a _γ′ The correlation of the observed A1₂O₃ lattices to the spinel lattice is discussed and translation of atom positions during theγ′ →γ →δ transformation is studied. All anions must change their positions by a small amount; one-third of the cation positions inγ′ and more than 90 pct of cation positions inδ experience a large translation during that transformation. This implies that for theγ′ it→γ} →δ transformation, the positions of cations in both lattices are important. The results are discussed in relation to the fiber-matrix interaction under spinel formation during thermal loading ofδ-Al₂O₃-fiber-reinforced aluminum piston alloys.     

Work stressors and wife abuse.

To assess whether work experiences and stressors are associated with wife abuse (WA), 18 maritally satisfied, 12 dissatisfied/nonabusive, and 18 dissatisfied/abusive husbands (mean age 35.3 yrs) completed work involvement, organizational commitment, job satisfaction, and work stress questionnaires (yielding occurrence, positive, and negative impact indices). Multiple analysis of variance (MANOVA) revealed that overall work experiences were significantly associated with WA. Univariate analyses of variance (ANOVAs) showed that only the occurrence of stressful work events and their negative impact were significantly associated with WA. Conceptual and methodological implications concerning the association between work stress and WA are suggested, and the needs for a true causal analyses on the effects of work stressors on WA and for a focus on personality and situational variables enhancing or reducing the likelihood of spouse abuse are emphasized. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of initial gamma prime size on the elevated temperature creep properties of single crystal nickel base superalloys

The influence of initial γ′ size and shape on the high temperature creep properties of two single crystal nickel-base superalloys was investigated. The two alloys were chosen to represent different magnitudes of γ-γ′ lattice mismatch. A range of initial microstructures was produced by various quenching and aging treatments. Creep-rupture testing at 1000 °C was performed under stresses where γ′ directionally coarsens to form γ-γ′ lamellae in the early portion of the creep life. Both alloys exhibited a peak in creep resistance as a function of initial γ′ size. The peak corresponded to an initial microstructure consisting of cuboidal precipitates aligned along [001] directions. These aligned cuboidal γ′ particles directionally coarsened into a relatively perfect lamellar γ-γ′ structure in the early stages of creep, whereas the more irregularly shaped and distributed γ′ particles in both under and overaged material formed more irregular lamellae with more imperfections. The alloy with a lower magnitude of mismatch was less sensitive to initial γ′size and shape.