RESUMO
Based on ab initio total energy calculation, we show that a dynamic ad-dimer twisting assisted (DATA) process plays a crucial role in facilitating a novel structural reconstruction involving surface and subsurface atoms on Si(001). It leads to self-assembly of long nanowires of group-V elements (Bi, Sb) in the trenches of surface dimer vacancy lines (DVLs) with a characteristic double-dimer configuration. The key to this is the lowering of the kinetic barrier by the DATA process in conjunction with a favorable interaction between ad-dimers and step edges in DVLs. The present results provide an excellent account for experimental observations and reveal the atomistic origin and the dynamic transformation path for nanowire self-assembly on Si(001).
RESUMO
We introduce a generalized ensemble of non-Hermitian matrices interpolating between the Gaussian Unitary Ensemble, the Ginibre ensemble, and the Poisson ensemble. The joint eigenvalue distribution of this model is obtained by means of an extension of the Itzykson-Zuber formula to general complex matrices. Its correlation functions are studied both in the case of weak non-Hermiticity and in the case of strong non-Hermiticity. In the weak non-Hermiticity limit we show that the spectral correlations in the bulk of the spectrum display critical statistics: the asymptotic linear behavior of the number variance is already approached for energy differences of the order of the eigenvalue spacing. To lowest order, its slope does not depend on the degree of non-Hermiticity. Close the edge, the spectral correlations are similar to the Hermitian case. In the strong non-Hermiticity limit the crossover behavior from the Ginibre ensemble to the Poisson ensemble first appears close to the surface of the spectrum. Our model may be relevant for the description of the spectral correlations of an open disordered system close to an Anderson transition.
RESUMO
We evaluated postoperative shrinkage of anterior capsule, depth of anterior chamber, and refraction in 161 eyes, on which we performed continuous curvilinear capsulorhexis and phacoemulsification, and then implanted an intraocular lens in the capsular bag. We measured the depth of anterior chamber, anterior capsulorhexis size, contact surface with intraocular lens, and quantity and rate of anterior capsular shrinkage on the basis of anterior segment photographs before the operation, and 1 week, 1 month, and 3 months after the operation. After operation the depth of the anterior chamber deepened gradually, anterior capsulorhexis size narrowed, and refraction tended to hyperopia. There was a correlation in anterior chamber depth and anterior capsulorhexis size between preoperative and postoperative values but no correlation in refraction. The depth of the anterior chamber was dependent on the degree of anterior capsular shrinkage. There was a correlation between the depth of anterior chamber and the degree of anterior capsular shrinkage.
Assuntos
Câmara Anterior/patologia , Cápsula do Cristalino/patologia , Lentes Intraoculares , Refração Ocular , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-OperatórioRESUMO
A case of malignant meningioma in a 78-year-old man is reported. It was found as a subcutaneous tumor of the scalp, following which some neurological symptoms were clinically noted. The tumor showed infiltrative growth and was located from the subcutaneous tissue to the meninges through the skull. Histologically, it was composed predominantly of spindle, epithelioid and bizarre tumor cells, but a whorl formation was also detected in a restricted area. The histogenesis of the present case and the relationship between the histopathological findings and clinical behavior of malignant meningioma are also discussed.
Assuntos
Neoplasias Meníngeas/patologia , Meningioma/patologia , Couro Cabeludo/patologia , Neoplasias Cutâneas/patologia , Idoso , Humanos , Masculino , Invasividade NeoplásicaRESUMO
The proximal left M1 and the common trunk of A2 were clipped in 12 adult dogs. Naloxone was injected after placing the clips onto 6 dogs. Neither the systemic blood pressure nor the local cerebral blood flow were influenced by naloxone. In another group of 6 dogs with chronic right hemiplegia, naloxone proved passably effective in improving the hemiplegia. Eight patients with neurological deficits of various etiologies were administered levallorphan. The improvement in motor performance and/or elevation of mental activity was observed more or less in all but 2 of the patients. It was considered that the effect of opiate antagonists is based partially on the facilitation of synaptic transmission exaggerated by the arousal response.
Assuntos
Isquemia Encefálica/tratamento farmacológico , Levalorfano/uso terapêutico , Naloxona/uso terapêutico , Doenças do Sistema Nervoso/tratamento farmacológico , Adulto , Idoso , Animais , Velocidade do Fluxo Sanguíneo , Isquemia Encefálica/complicações , Gatos , Circulação Cerebrovascular/efeitos dos fármacos , Embrião de Galinha , Modelos Animais de Doenças , Cães , Feminino , Humanos , Injeções Intravenosas , Masculino , Pessoa de Meia-Idade , Antagonistas de Entorpecentes/uso terapêutico , Doenças do Sistema Nervoso/etiologia , Tomografia Computadorizada por Raios XRESUMO
Intracarotid CDDP infusion in combination with angiotensin II was performed in two patients with metastatic brain tumor, lung carcinoma (LC) and ovarian carcinoma (OC). The patient with OC received 40 mg/m2 CDDP while the other patient with LC was administered intra-arterially with 50 mg/m2 CDDP, 30 mg/m2 ADM and 2.5 mg/m2 MMC. 50% or greater reduction in the size of metastatic lesions was observed in both patients in whom no neurological toxicities developed. Intra-arterial infusion of CDDP either alone or in combination with ADM or MMC seems to present an aggressive approach in dealing with other metastatic neoplasms without increasing toxicity, especially if intra-arterial angiotensin II is infused concomitantly.