Due to the biological importances of thiols, such as cysteine, homocysteine and glutathione, the development of optical probes for thiols has been an active research area in recent few years. This critical review focuses on the fluorescent or colorimetric sensors for thiols according to their unique mechanisms between sensors and thiols, including Michael addition, cyclization with aldehyde, cleavage of sulfonamide and sulfonate ester by thiols, cleavage of selenium–nitrogen bond by thiols, cleavage of disulfide by thiols, metal complexes-oxidation–reduction, metal complexes-displace coordination, nano-particles and others (110 references).

Fluorescent and colorimetric probes for detection of thiols

On the basis of a spin-polarised density functional description of the electrons, the authors develop a 'mean-field' theory of magnetic phase transitions in metals. The one-electron-like finite-temperature Schrodinger equation is solved, formally, for random orientations of local moments and the corresponding grand potential is used in a statistical mechanics of the spin configurations. This latter, in the mean-field approximation, requires the knowledge of the electronic grand potential averaged over various ensembles of such 'spin' configurations. These averages are carried out with the help of the Korringa-Kohn-Rostoker coherent-potential-approximation (KKR CPA) method for dealing with electrons in random potential fields. Then, the whole procedure is made self-consistent on the average. The theory determines the local moment mu , the Curie temperature TC, and the susceptibility chi (q,T) in addition to the electronic structure at finite temperatures without adjustable parameters. The authors illustrate the explicit calculations for iron. The local moment is found to be 1.9 mu B above TC, and the preliminary estimate of Tc is 1250K.

https://iopscience.iop.org/article/10.1088/0305-4608/15/6/018/pdf

A first-principles theory of ferromagnetic phase transitions in metals

In 2008, we published an article arguing that the age-related loss of muscle strength is only partially explained by the reduction in muscle mass and that other physiologic factors explain muscle weakness in older adults (Clark BC, Manini TM. Sarcopenia =/= dynapenia. J Gerontol A Biol Sci Med Sci. 2008;63:829-834). Accordingly, we proposed that these events (strength and mass loss) be defined independently, leaving the term "sarcopenia" to be used in its original context to describe the age-related loss of muscle mass. We subsequently coined the term "dynapenia" to describe the age-related loss of muscle strength and power. This article will give an update on both the biological and clinical literature on dynapenia-serving to best synthesize this translational topic. Additionally, we propose a working decision algorithm for defining dynapenia. This algorithm is specific to screening for and defining dynapenia using age, presence or absence of risk factors, a grip strength screening, and if warranted a test for knee extension strength. A definition for a single risk factor such as dynapenia will provide information in building a risk profile for the complex etiology of physical disability. As such, this approach mimics the development of risk profiles for cardiovascular disease that include such factors as hypercholesterolemia, hypertension, hyperglycemia, etc. Because of a lack of data, the working decision algorithm remains to be fully developed and evaluated. However, these efforts are expected to provide a specific understanding of the role that dynapenia plays in the loss of physical function and increased risk for disability among older adults.

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Dynapenia and Aging: An Update

Sarcopenia is a loss of muscle mass and function in the elderly that reduces mobility, diminishes quality of life, and can lead to fall-related injuries, which require costly hospitalization and ex...

/pdf/sarcopenia-aging-related-loss-of-muscle-mass-and-function-2u9nyjfrxt.pdf

Sarcopenia: Aging-Related Loss of Muscle Mass and Function.

Bed rest studies of the past 20 years are reviewed. Head-down bed rest (HDBR) has proved its usefulness as a reliable simulation model for the most physiological effects of spaceflight. As well as continuing to search for better understanding of the physiological changes induced, these studies focused mostly on identifying effective countermeasures with encouraging but limited success. HDBR is characterised by immobilization, inactivity, confinement and elimination of Gz gravitational stimuli, such as posture change and direction, which affect body sensors and responses. These induce upward fluid shift, unloading the body’s upright weight, absence of work against gravity, reduced energy requirements and reduction in overall sensory stimulation. The upward fluid shift by acting on central volume receptors induces a 10–15% reduction in plasma volume which leads to a now well-documented set of cardiovascular changes including changes in cardiac performance and baroreflex sensitivity that are identical to those in space. Calcium excretion is increased from the beginning of bed rest leading to a sustained negative calcium balance. Calcium absorption is reduced. Body weight, muscle mass, muscle strength is reduced, as is the resistance of muscle to insulin. Bone density, stiffness of bones of the lower limbs and spinal cord and bone architecture are altered. Circadian rhythms may shift and are dampened. Ways to improve the process of evaluating countermeasures—exercise (aerobic, resistive, vibration), nutritional and pharmacological—are proposed. Artificial gravity requires systematic evaluation. This review points to clinical applications of BR research revealing the crucial role of gravity to health.

From space to Earth: advances in human physiology from 20 years of bed rest studies (1986–2006)

Nine healthy men carried out head-down bed rest (BR) for 20 days Five subjects (TR) performed isometric, bilateral leg extension exercise every day, while the other four (NT) did not Before and after BR, maximal isometric knee extension force was measured Neural activation was assessed using a supramaximal twitch interpolated over voluntary contraction From a series cross-sectional magnetic resonance imaging scans of the thigh, physiological cross-sectional areas (PCSA) of the quadriceps muscles were estimated (uncorrected PCSA, volume/estimated fibre length) Decrease in mean muscle force after BR was greater in NT [−109 (SD 69)%, P < 005] than in TR [05 (SD 79)%, not significant] Neural activation did not differ between the two groups before BR, but after BR NT showed smaller activation levels Pennation angles of the vastus lateralis muscle, determined by ultrasonography, showed no significant changes in either group The PCSA decreased in NT by −78 (SD 08)% (P < 005) while in TR PCSA showed only an insignificant tendency to decrease [−38 (SD 38)%] Changes in force were related more to changes in neural activation levels than to those in PCSA The results suggest that reduction of muscle strength by BR is affected by a decreased ability to activate motor units, and that the exercise used in the present experiment is effective as a countermeasure

Changes in muscle size, architecture, and neural activation after 20 days of bed rest with and without resistance exercise.

The dynamical properties of two spin systems composed of conduction electron spins and' localized d-spins interacting by exchange are investigated in connection with the electron-spin resonance of d-spins with the free electron g-value. It seems to us that some basic consider­ ations are necessary for the problem along the line of the widely accepted idea that the s-d' interaction itself does not lead to any relaxation time and shift. The usual adiabatic approx­ imation is applied to this idea. A modified damping equation of the Bloch type as well as. Bloch's relaxation theory are also useful, but these are not enough for a complete solution of the problem. A certain controversy involved in recent experimental and theoretical work at Berkeley concerning the electron spin resonance in Cu-Mn dilute alloy is pointed out and examined.. We believe that the possibility could not be eliminated that the spin-lattice re­ laxation time of conduction electrons in the alloy due to mechanisms other than the sod' interaction is longer than previous authors have assumed.

/pdf/dynamical-properties-of-s-d-interaction-3e7gofi71d.pdf

Dynamical Properties of s-d Interaction

The free energy of bcc, fcc, and hcp iron has been calculated as a function of temperature and pressure within the single-site spin-fluctuation theory of band magnetism, which has been developed recently by Hubbard and Hasegawa The simple theory can account for the occurrence of the $\ensuremath{\alpha}$, $\ensuremath{\gamma}$, $\ensuremath{\delta}$, and $\ensuremath{\epsilon}$ phases in the $T\ensuremath{-}P$ phase diagram of iron, the phase transitions being driven by the magnetic contributions to the free energy

Microscopic Theory of the Temperature-Pressure Phase Diagram of Iron

A quantummechanical theory of galvanomagnetic effect is developed on the basis of the general theory of irreversible processes previously reported by Kubo (J. Phys. Soc. Japan 12 (1957) 570). The present theory applies to arbitrary shape of Fermi surface, as far as it makes a closed surface in the momentum space. Complications due to the interband effect and Harper's broadening effect are neglected here. On these assumptions it is proved that the static conductivity can be expressed generally in terms of the migration process of the center coordinate of the cyclotron motion. This is based on the assumption that the relative coordinates to describe the cyclotron motion are essentially bounded quantities in classical and also in quantummechanical sense. Without referring to any dubious use of transport theory, a very satisfactory logical basis is thus obtained for treating galvanomagnetic effect. This method is particularly useful for strong field. Applications will be reported in a subsequent paper.

Quantum Theory of Galvanomagnetic Effect. I. Basic Considerations

Rosuvastatin is a new 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor. The liver is the target organ for the lipid-regulating effect of rosuvastatin; therefore liver-selective uptake of this drug is a desirable property. The aim of this study was to investigate, and compare with pravastatin and simvastatin, the tissue-specific distribution of rosuvastatin. Bolus intravenous doses (5 mg/kg) of radiolabeled rosuvastatin, pravastatin, and simvastatin were administered to rats, and initial uptake clearance (CL(uptake)) in various tissues was calculated. Hepatic CL(uptake) of rosuvastatin (0.885 ml/min/g tissue) was significantly (p < 0.001) larger than that of pravastatin (0.703 ml/min/g tissue), and rosuvastatin was taken up by the hepatic cells more selectively and efficiently than pravastatin. Hepatic CL(uptake) of simvastatin (1.24 ml/min/g tissue) was significantly larger than that of rosuvastatin (p < 0.01) and pravastatin (p < 0.001). However, adrenal CL(uptake) of simvastatin (1.55 ml/min/g tissue) was larger than hepatic CL(uptake), and simvastatin was distributed to other tissues more easily than rosuvastatin. Microautoradiography of the liver, spleen, and adrenal was undertaken 5 min after administration of the study drugs; distribution was quantified by counting the number of silver grains. After administration of rosuvastatin and pravastatin, silver grains were distributed selectively in the intracellular space of the liver, but more rosuvastatin (3.3 +/- 1.0 x 10(5) particles/mm(2)) than pravastatin (2.0 +/- 0.3 x 10(5) particles/mm(2)) tended to distribute to the liver. Simvastatin was less liver-specific (it also distributed to the spleen and adrenal). The results of this study indicated that rosuvastatin was taken up by hepatic cells more selectively and more efficiently than pravastatin and simvastatin.

Hiroshi Hasegawa

Papers

Changes in muscle size, architecture, and neural activation after 20 days of bed rest with and without resistance exercise.

Dynamical Properties of s-d Interaction

Microscopic Theory of the Temperature-Pressure Phase Diagram of Iron

Quantum Theory of Galvanomagnetic Effect. I. Basic Considerations

Liver-specific distribution of rosuvastatin in rats: comparison with pravastatin and simvastatin.