Analytic bond-order potentials for the bcc refractory metals Nb, Ta, Mo and W.

Bond-order potentials (BOPs) are based on the tight-binding approximation for determining the energy of a system of interacting atoms. The bond energy and forces are computed analytically within the formalism of the analytic BOPs. Here we present parametrizations of the analytic BOPs for the bcc refractory metals Nb, Ta, Mo and W.

Origin of brittle cleavage in iridium.

Iridium is unique among the face-centered cubic metals in that it undergoes brittle cleavage after a period of plastic deformation under tensile stress. Atomistic simulation using a quantum-mechanically derived bond-order potential shows that in iridium, two core structures for the screw dislocation are possible: a glissile planar core and a metastable nonplanar core. Transformation between the two core structures is athermal and leads to exceptionally high rates of cross slip during plastic deformation.

Analytic environment-dependent tight-binding bond integrals: application to MoSi2.

We present the first derivation of explicit analytic expressions for the environmental dependence of the sigma, pi, and delta bond integrals within the orthogonal two-center tight-binding approximation by using the recently developed bond-order potential theory to invert the nonorthogonality matrix. We illustrate the power of this new formalism by showing that it not only captures the transferability of the bond integrals between elemental bcc Mo and Si and binary C11(b) MoSi2 but also predicts the absence of any discontinuity between first and second nearest neighbors for the ddsigma bond integral even though large discontinuities exist for ppsigma, pppi, and ddpi.

Thyroid hormone alterations in patients with shock and injury.

Serum concentrations of total T3 and T4, free T4, rT3, TSH, TBG and cortisol were measured on arrival in hospital in 33 adult injured patients, 26 of whom were received directly from the accident. Serum cortisol levels and all thyroid indices, except TBG, were altered substantially by injury. Compared with values from 57 healthy volunteers, statistically significant (P less than 0.

Effect of sleep deprivation on cholesterol metabolism and triglyceridaemia in male volunteers.

The effect of 5-day sleep deprivation (SD) on cholesterol metabolism, together with triglyceridaemia, was studied in seven healthy male volunteers. A 3-day control period was followed by 5 days (120 h) complete SD and 4 days recovery. Blood was collected at 9 a.

Fractional cholesterol esterification rate and muscle cholesterol of healthy young men.

A group of fourteen healthy young male volunteers was examined to define more exactly the relations between lecithin cholesterol acyltransferase activity (LCAT), fractional cholesterol esterification rate (FER), total cholesterol (TC) and its free and esterified fractions (FC, CE) in skeletal muscles under physiological conditions. The mean values (+/- S.D.

Relationship of thyroid hormone patterns to survival in canine hemorrhagic shock.

6 of 13 dogs subjected to 1 h of hemorrhagic shock (BP = 45-50 mm Hg) died during the first convalescent day. Nonsurvivors had lower baseline plasma concentrations of total and free T4 and T3, as well as rT3, and higher T3 uptake values. During shock, dogs that died had significantly lower plasma levels of total and free T4 and T3 and higher T3 uptake.

Bleomycin stimulates both membrane (Na+-K+) ATPase and electrogenic (Na+-K+) pump and partially removes the inhibition by vanadium ions.

Bleomycin 2 X 10(-6) and 6 X 10(-6) mol.1(-1) increased the activity of specific (Na+-K+) ATPase of the rat brain microsomes. It also stimulated the electrogenic (Na+-K+) pump in intact skeletal muscle cells.

The effect of five days' fasting on skeletal muscle enzymes in obese men.

The effect of 120 hours' (five days) fasting on the activity of some enzymes of energy metabolism in skeletal muscles was investigated in six obese young men. The results revealed a significant decline in the activity of the following enzymes: triosophosphate dehydrogenase (by 20%), glycerol-3-phosphate dehydrogenase (by 24%), lactate dehydrogenase (by 13%), citrate synthase (by 20%), hydroxyacyl-CoA dehydrogenase (by 40%), while the hexokinase and malate dehydrogenase activities were not significantly altered. Contrary to muscles of non-obese healthy men (Vondra, Bass, Brodan, Kuhn, Andĕl, Veselková and Vítek 1982), a smaller decline of activities of the investigated enzymes occurred together with a paradoxical change of the enzyme pattern, namely a predominance of carbohydrate catabolism and a decline of the role of fatty acids in muscle energy metabolism.

Thyroid hormone responses in hemorrhagic shock: study in dogs and preliminary findings in humans.

One hour of hemorrhagic shock in the dog produces alterations in thyroid hormone metabolism far exceeding those seen after elective surgery or thermal injury. The changes in plasma thyroid hormone levels cannot be fully explained by carrier protein loss. Plasma concentrations of total thyroxine (T4) and triiodothyronine (T3) were significantly decreased after only 20 minutes of shock, continued to decrease throughout shock and resuscitation, and remained depressed for several days thereafter.

Aggravating effect of alcohol on admission serum insulin patterns of patients with trauma and in a state of shock.

The effect of alcohol upon admission serum insulin levels was studied in 114 injured patients with mean blood alcohol levels of 130 +/- 71 milligrams per deciliter, ranging from 10 to 350. These data were compared with those of 133 similar patients with no measurable blood alcohol levels and with those of 47 healthy volunteers. Whereas marked hyperglycemia caused by trauma or shock was unaffected by alcohol ingestion, insulin levels were more depressed in patients with blood alcohol levels 29.

Effect of etiroxate on LCAT activity and on certain energy metabolism enzymes in the rat.

Etiroxate (Skleronorm Grünenthal R) was administered 42 days to male Wistar rats and their serum and liver cholesterol and triglyceride levels, the rate of esterification of free cholesterol in their plasma by lecithin cholesterol acyltransferase (LCAT) (EC 2.3.1.

Postnatal changes of some enzymatic activities of energy supplying metabolism in the cortex, inner and outer medulla of the rat kidney.

1. In rat kidney cortex, outer and inner medulla the development of activities of seven enzymes was investigated during postnatal ontogeny (10, 20, 30, 60 and 90 days of age). The enzymes were selected in such a manner, as to characterize most of the main metabolic pathways of energy supplying metabolism: hexokinase (glucose phosphorylation, HK), glycerol-3-phosphate dehydrogenase (glycerolphosphate metabolism or shunt, GPDH), triose phosphate dehydrogenase (glycolytic carbohydrate breakdown, TPDH), lactate dehydrogenase (lactate metabolism, LDH), citrate synthase (tricarboxylic acid cycle, aerobic metabolism, CS), malate NAD dehydrogenase (tricarboxylic acid cycle, intra-extra mitochondrial hydrogen transport, MDH) and 3-hydroxyacyl-CoA-dehydrogenase (fatty acid catabolism, HOADH).