The linear-chain states of 14 C are theoretically investigated by using the antisymmetrized molecular dynamics. The calculated excitation energies and the α decay widths of the linear-chain states were compared with the observed data reported by recent experiments. The properties of the positive-parity linear-chain states reasonably agree with the observation, which convinces us of the linear-chain formation in the positive-parity states. On the other hand, in the negative-parity states, it is found that the linear-chain configuration does not correspond to a single eigenstate but is mixed with other configurations in the eigenstates and does not form a single rotational band. As a further evidence of the linear-chain formation, we focus on the α-decay pattern. It is shown that the linear-chain states decay to the excited states of daughter nucleus 10 Be as well as to the ground state, while other cluster states dominantly decay into the ground state. Hence, we regard that this characteristic decay pattern is a strong signature of linear-chain formation.

An ab initio zeroth-order regular approximation (ZORA) theory for relativistic calculation of the nuclear magnetic shielding tensors is presented at the Hartree–Fock level. The nuclear magnetic shieldings tensors of hydrogen halides, HX (X=F, Cl, Br, and I), are calculated, and the results are compared to experimental values and other calculated results obtained using the Douglas–Kroll–Hess (DKH) transformation, the four-component random phase approximation (RPA), and the Dirac–Fock (DF) approaches. It is shown that the ZORA method underestimates the relativistic effects on the magnetic shieldings as compared to the four-component RPA results. However, as to the proton chemical shifts, the ZORA results are closer to the experimental proton shifts than those of the DKH and 4-RPA approaches.

A mutation of endothelial nitric oxide synthase (ecNOS)-a key enzyme of the endogenous nitrovasodilator system that is essential for the regulation of blood flow and blood pressure-may aggravate the progression to diabetic nephropathy and/or retinopathy. To investigate the association of ecNOS tandem repeat polymorphism with diabetic nephropathy, the ecNOS genotype was assessed in 82 Japanese type 2 diabetic patients without nephropathy, 94 patients with microalbuminuria, 39 patients with nephropathy, and 1 5 5 healthy control subjects. The analysis revealed that type 2 diabetic patients with nephropathy (not with microalbuminuria) were significantly diff e r e n t from type 2 diabetic patients without nephropathy and healthy control subjects in genotype distribution (P = 0.0423) and frequency of the ecNOS4a allele (19.2% vs. 7.3 and 7.1%, respectively; P = 0.0078). The odds ratio of progression to diabetic nephropathy in diabetic patients who carry the mutated allele is about 2.87 compared with noncarriers. The stepwise multiple regression analysis in these patients showed that hypertension (F = 9.760) and ecNOS gene polymorphism (F = 5.298) are the relevant variables for n e p h r o p a t h y. However, no association was found between the ecNOS4a allele and hypertension or diabetic retinopathy. These results imply that the ecNOS gene polymorphism may be associated with progression to diabetic nephropathy in Japanese type 2 diabetic patients. D i a b e t e s 4 9 :5 0 0-503, 2000 N itroglycerin has been used for more than a century as a vasodilator for the treatment of coronary heart disease. Previous studies have confir m e d that an endogenous nitrovasodilator system in humans maintains a physiological vasodilator tone. In response to stimuli, such as hypoxia, shear stress, and pulsatile flo w, vascular endothelium cells synthesize picomoles of nitric oxide (NO) from the amino acid L-arginine by a constitutive, calcium/calmodulin dependent enzyme, endothelial cellular nitric oxide synthase (ecNOS) (1). The intraluminal release of NO mediates local vasodilatation (1,2) and antagonizes platelet aggregation (1-3) and inhibits vascular smooth muscle cell proliferation (2). The deletion of one of five nucleotide repeats (27 bp) in intron 4 (ecNOS4a allele) was suggested to be associated with coronary artery disease in Australian current and ex-smokers (4). The important role of NO release in the regulation of basal or stimulated vasodilatation suggests that an abnormal ecNOS activity due to a mutation could be implicated in different pathological conditions, such as hypertension and atherosclerosis, and may therefore aggravate retino-and/or renovascular injury in diabetic patients. Based on this rationale, we investigated the association of the ecNOS gene polymorphism with diabetic nephropathy and retinopathy in type 2 diabetic patients in a cross-sectional study. We demonstrated that this polymorphism is a risk factor for advanced diabetic nephropathy.The ecNOS genotype was assessed in 287 (n = 136 with retinopath...

No abstract

The α-cluster states of 16 C are investigated by using antisymmetrized molecular dynamics. It is shown that two different types of α-cluster states exist: triangular and linear-chain states. The former has an approximate isosceles triangular configuration of α particles surrounded by four valence neutrons occupying the sd shell, while the latter has the linearly aligned α particles with (sd) 2 (pf ) 2 neutrons. It is found that the structure of the linear-chain state is qualitatively understood in terms of the 3/2 − π and 1/2 − σ molecular orbits as predicted by molecular-orbital model, but there exists a non-negligible 10 Be + α + 2n correlation. The bandhead energies of the triangular and linear-chain rotational bands are 8.0 and 15.5 MeV, and the latter is close to the 4 He + 12 Be and 6 He + 10 Be threshold energies. It is also shown that the linear-chain state becomes the yrast state at J π = 10 + with E x = 27.8 MeV owing to its very large moment of inertia comparable with hyperdeformation.