Search

We describe the design and development of an injection seeded Nd:YVO4 laser for use in a differential fluorescence lidar for measuring atmospheric formaldehyde profiles. A high repetition rate Q-switched laser is modified to accept injection seed input to spectrally narrow and tune the output. The third harmonic output is used to excite formaldehyde (HCHO) fluorescence when tuned to a HCHO absorption line. Spectral confirmation is made with the use of a photoacoustic cell and grating spectrometer.

Ciglitizone, a class of thiazolidinediones, acts as a potent activator of the adipose differentiation program in established preadipose cell lines. Thiazolidinediones have also been investigated in diabetic patients and have been reported to act as peroxisome proliferator-activated receptor-[gamma] ligands. Intramuscular adipogenesis or marbling through transdifferentiation of satellite cells in cattle was successfully conducted earlier. In this report, the effects of ciglitizone on the differentiation pathway of porcine myogenic satellite cells was investigated. Semitendinosus muscle was aseptically taken from 10-d-old piglets under general anesthesia, and porcine satellite cells were obtained and grown to near confluence. Postconfluent cells (d 0) were further cultured in differentiation medium containing an adipogenic mixture plus ciglitizone (10 [micro]M) for 48 h. From d 2 onward, the cells were cultured only in the presence of ciglitizone until d 10. Controls were cultured in differentiation medium only. Exposure of porcine satellite cells to the adipogenic mixture plus ciglitizone generated lipid droplets on d 2, and subsequently, exposure of cells to ciglitizone alone helped in cytoplasmic lipid filling, providing them with the acquisition of adipocyte morphology. An increase (P < 0.05) in the fusion (structures containing 2 to 3 nuclei) of satellite cells was observed, and myosin heavy chain appeared with greater intensity (immunohistochemistry) in the control group from d 2 onward. Adipocytespecific transcriptional factors (i.e., CCAAT/enhancer binding protein-[alpha] and peroxisome proliferator-activated receptor-[gamma] were predominant during transdifferentiation and were observed with immuhistochemistry, Western blot (-47.2 and -60.4 kDa, respectively), and real-time PCR. Ciglitizone appeared to convert the differentiation pathway of satellite cells into that of adipoblasts. Key words: adipogenesis, ciglitizone, CCAAT/enhancer binding protein-[alpha], myogenesis, peroxisome proliferator-activated receptor-[gamma]

In this study, we characterized the effects of 25-hydroxyvitamin [D.sub.3] (25-OH [D.sub.3]) and manipulated dietary cation-anion difference (DCAD) on the performance, urine pH, serum constituents, carcass traits, tissue residual vitamin D and its metabolites, beef tenderness, and mRNA and protein concentrations of Ca-dependent proteinases in LM using 24 cull native Korean cows. The cows were divided into 3 groups of 8: control, 25-OH [D.sub.3] supplemented (25-OH [D.sub.3]), and manipulated DCAD plus 25-OH [D.sub.3] supplemented (DCAD+25-OH [D.sub.3]). Cows receiving 25-OH [D.sub.3] or DCAD+25-OH [D.sub.3] were dosed with 125 mg of 25-OH [D.sub.3] 6 d before slaughter. The manipulated DCAD (-10 mEq/ 100 g of DM) diet was fed from 20 to 6 d (14 d) before slaughter. The DCAD+25-OH Ds treatment decreased urine pH and increased serum Ca concentrations. Although the vitamin D concentrations in LM, liver, and kidney were not affected by 25-OH [D.sub.3] or DCAD+25-OH [D.sub.3], muscle tissue 25-OH Ds concentrations were increased by both regimens. Serum 25-OH [D.sub.3] concentrations were increased by 25-OH [D.sub.3] supplementation, and the increase was even greater for DCAD+25-OH [D.sub.3]. The same pattern was observed for serum 1,25-[(OH).sub.2] [D.sub.3]. However, the LM concentration of 1,25-[(OH).sub.2] [D.sub.3] was less for DCAD+25-OH [D.sub.3] than for control. Although Ca concentrations of LM increased numerically in response to 25-OH [D.sub.3] supplementation, no statistical differences in Warner-Bratzler shear force or sensory traits of LM were detected. The LM of cows receiving 25-OH Ds with or without manipulated DCAD had greater concentrations of [micro]-calpain and m-calpain mRNA, whereas the reverse was observed for calpastatin mRNA. Expression of [micro]-calpain protein was increased relative to control by DCAD+25-OH [D.sub.3]. The amount of 25-OH [D.sub.3] and manipulated DCAD administered to cull native Korean cows was insufficient to improve tenderness of beef by increasing muscle Ca concentration. However, DCAD+25-OH [D.sub.3] induced greater expressions of [micro]-calpain protein as well as mRNA. Key words: anion, beef, calcium, 25-hydroxyvitamin [D.sub.3], tenderness

Interactions between muscle shortening and proteolysis and their effects on Warner–Bratzler (WB) shear force were investigated in beef m. longissimus (LD) and m. semitendinosus (ST). Muscles were taken within 30 post-mortem from eight Hanwoo steers, divided into three portions, and incubated at 5, 15, or 36 °C for 24 h, during which time rigor mortis developed. ST at 36 °C had a significantly (P<0.05) lower pH at 3 h than LD incubated at the same temperature. However, pH values became similar after 3 h. Both muscles at 5 and 15 °C had almost similar pH during rigor development, with significantly (P<0.05) lower pH for ST. Sarcomere length and WB-shear force did not differ significantly between muscles incubated at the same temperature. For both muscles at 5, 15, and 36 °C, sarcomere length was 1.52, 1.76 and 1.44 μm, and WB shear force was 93.2, 55.9 and 45.1 N. The rates of μ-calpain autolysis and Troponin-T degradation were in the order of 36 °C > 15 °C⩾5 °C, with a tendency for ST to have a slightly faster rate than LD muscle. Thus, the effect of sarcomere length on shear force may depend on the extent of proteolysis and the potential of endogenous proteolysis may supersede toughness caused by short sarcomeres. The toughness of cold shortened meat may depend more on endogenous enzymatic tenderization than shortened sarcomere length per se. [Copyright &y& Elsevier]

The thermo-viscoelastic boundary value problem for anisotropic materials is formulated and a numerical procedure is developed for the efficient analysis of stress and deformation histories in composites. The procedure is based on the finite element method and therefore it is applicable to composite laminates containing geometric discon tinuities and complicated boundary conditions. Using the present formulation, the time- dependent stress and strain distributions in both notched and unnotched graphite/epoxy composites have been obtained. The effect of temperature and ply orientation on the creep and relaxation response is also studied. [ABSTRACT FROM PUBLISHER]