Kinetic analysis of ATP-synthetase and ATPase in regenerating rabbit liver

The activities of ATP-synthetase and ATPase in rabbit liver were evaluated by kinetic analysis of rapid changes in ATP during alteration of oxygen supply, and were compared between normal and hepatectomized rabbits. Velocity constants of ATP-synthetase and ATPase were computed on the assumption that ATP-synthetase and ATPase follow the pseudo-first order reaction of ADP and ATP, respectively. The velocity constant of ATPase increased from the control value of 0.21 to 0.48 (min-1) in the remnant rabbit liver at 24 h after 70% hepatectomy. The velocity constant of ATP-synthetase increased from the control value of 4.05 to 5.24 (min-1) after the hepatectomy. These results indicate that both ATP-synthetase and ATPase are accelerated due to liver regeneration.     

Redox regulation of caspase-3(-like) protease activity: regulatory roles of thioredoxin and cytochrome c

Oxidative stress induces a variety of cellular responses, including apoptosis, and caspase family proteases are known to be involved in apoptosis. Caspase-3(-like) protease activity was examined in Jurkat T cells to investigate the mechanism of apoptosis induced by a thioloxidant, diamide. Caspase-3 was activated when cells were cultured with 200 microM diamide that induced apoptosis, whereas no caspase-3 activation was detected with 500 microM diamide that induced necrosis. When apoptosis was induced in cells with exposure to 200 microM diamide, the intracellular thioredoxin (TRX) levels were maintained and the intracellular generation of reactive oxygen intermediates was marginal. The cytosolic fractions of cytochrome c were increased earlier than the activation of caspase-3. In contrast, when cells were exposed to 500 microM diamide, intracellular reactive oxygen intermediate generation was increased and processing of caspase-3 was not detected despite cytochrome c release, resulting in necrosis. Caspase-3 activity in cell lysate precultured with anti-Fas Ab was suppressed dose dependently by diamide and restored by thiol-reducing agents, DTT or TRX. When cells were precultured with 5 mM of buthionine sulfoximine, an inhibitor of glutathione synthesis, intracellular TRX levels were maintained, and as low as 20 microM diamide could induce apoptosis associated with the increase of cytosolic cytochrome c and the activation of caspase-3. These results indicate that the activation of caspase-3 in diamide-induced apoptosis is mediated, at least partly, by cytochrome c release from mitochondria, and the cellular reducing environment maintained by TRX, as well as glutathione, is required for caspase-3 activity to induce apoptosis.     

Intratumoral administration of neocarzinostatin conjugated to monoclonal antibody A7 in a model of pancreatic cancer

PURPOSE: To evaluate the effects of age on mechanical performance of rat myocardium. METHODS: Left ventricular papillary muscles were isolated from male Wistar rats at 1, 3, 6 and 12 months of age. Muscles were studied isometrically and isotonically, stimulated at 0.2 Hz, perfused with Krebs-Henseleit solution having an external calcium concentration of 2.52 mM, and maintained at 28 degrees C. RESULTS: Peak isometric developed tension was significantly higher in 1 month than 3, 6 and 12 months. Peak rate of isometric tension rise decreased substantially between 1, 3 and 12 months. Time to peak isometric developed tension showed a significant increase of both 3 and 12 months of age. Time to half relaxation increased significantly from 3 to 6 and from 3 to 12 months. Maximum rate of tension decline decreased from 3 to 6 and from 3 to 12 months. No difference in resting tension was noted among any group. Isotonically, peak shortening and time to peak shortening increased from 1 to 3 months of age. Time to half re-lengthening increased from 3 to 6 and from 3 to 12 months of age. No difference in peak shortening velocity, peak relaxation velocity and relative change in muscle length was noted among any groups. CONCLUSION: The maturation affects the mechanical performance of cardiac muscle.     

Mechanical Properties of Polycrystalline Translucent Cubic Boron Nitride as Characterized by the Vickers Indentation Method

Mechanical properties of polycrystalline translucent cubic boron nitride (cBN) were characterized by Vickers indentation measurement. The calculated hardness decreased from 54 to 49 GPa as the load increased to 39 N, and then remained constant for values above this load. According to the relationship between crack length and applied indentation load, the formation of the median/radial type of cracks seems to take place at an applied load above 29 N. Assuming that the ratio of hardness and Young's modulus is constant in the polycrystalline cBN, the fracture toughness, K_IC , of cBN was estimated to be 5.0 ± 0.5 MPa·m^1/2.     

Impact ionisation ratio in In0.73Ga0.27As0.57P0.43

A window structure InGaAsP avalanche photodiode (a.p.d.) has been fabricated by using liquid-phase epitaxy on (111B) InP. Multiplication characteristics show that the impact ionisation rate for electrons is larger than that for holes (?>?). The ionisation ratio ?/? was estimated to be 3?4. A low-noise a.p.d. will be realised by a structure with electron-initiated multiplication.     

Dendri-LEC Family: Establishing the Bright Future for Dendrimer Emitters in Traditional and Graphene-Based Light-Emitting Electrochemical Cells

A rational implementation and optimization of thermally activated delayed fluorescent (TADF) dendrimer emitters in light-emitting electrochemical cells (LECs) sets in the Dendri-LEC family. They feature outstanding stabilities (90/1050 h for green/yellow devices) that are comparable to the best green/yellow Ir(III)-complexes (450/500 h) and conjugated polymers (33/5500 h), while offering benefits of low-cost synthesis and easy upscaling. In particular, a fundamental molecular design that capitalizes on exchanging peripheral substituents (tert-butyl vs methoxy) to tune photophysical, electrochemical, morphological, and ion conductivity features in thin films is rationalized by temperature-dependent steady-state and time-resolved emission spectroscopy, cyclic voltammetry, atomic force microscopy, and electrochemical impedance spectroscopy techniques. Herein, a TADF mechanism associated to a reduced photoluminescence quantum yield, but an enhanced electrochemical stability and ion conductivity enables to clarify the reduced device efficiency and brightness (4.0 lm W⁻¹@110 cd m⁻² vs 3.2 lm W⁻¹@55 cd m⁻²) and increased stability (90 vs 1050 h) upon using methoxy groups. What is more, this substitution enables an excellent compatibility with biogenic electrolytes keeping device performances (1.9 lm W⁻¹@35 cd m⁻² and 1300 h), while graphene-devices achieve on par figures to traditional indium–tin oxide-devices. Overall, this work establishes the bright future of dendrimer emitters toward highly stable and truly sustainable lighting sources.