Optical Properties of Low-Loss Ag Films and Nanostructures on Transparent Substrates.

We demonstrate the fabrication of a low-loss single-crystalline Ag nanostructure deposited on transparent substrates. Our approach is based on an epitaxial growth technique in which a NaCl(001) substrate is used. The NaCl substrate is dissolved in water to allow the Ag film to be transferred onto the desired substrates. Focused ion beam milling is subsequently employed to pattern a nanoarray structure consisting of 200 nanorods. The epitaxial Ag films with nanoarray structures grown in the study exhibited very flat and smooth surfaces having excellent crystallinity and local misorientation of less than 1°. Further, spectroscopic ellipsometry measurements indicated that the imaginary part of the dielectric constant of the single-crystalline film was smaller than that of a conventional polycrystalline film. Moreover, we used the three-dimensional finite-difference time-domain method to analyze the plasmonic properties of the nanoarray structure by considering the actual processed structure. Characteristically, when the SiO2 substrate was etched by ion beam milling to a depth of 30 nm, the spectrum showed a spectral shape 20% sharper than that of the substrate with no etching (depth: 0 nm). The plasmonic performance of the single-crystalline Ag nanostructure was largely determined by its structural precision and the dielectric properties of the metal.

Nonlinear trimer resonators for compact ultra-fast switching.

We propose and numerically verify a scheme for compact optical modulation which can enable complex directional switching of signals in integrated micro-optical circuits within hundreds of femtoseconds. The scheme is based on a trimer comprised of two identical silica whispering gallery mode (WGM) microresonators spaced by a central non-linear WGM resonator. The non-linear resonator is in the form of a silica cylinder with a thin coating of an ultrafast Kerr nonlinear material (a J-aggregate of cyanine dye). Using a two-dimensional finite-difference time-domain method and realistic material and structural parameters, we investigated the near-field coupling from a waveguide to the trimer and the subsequent switching process. In our scheme the sandwiched central control resonator has a resonant frequency that is mismatched to that of the input and output resonators. Therefore the optical energy is coupled from the waveguide into only the primary resonator in linear operation. However, for control light intensities of more than approximately 10(-2) W/microm the effective index and hence eigenfrequency of the central resonator can be shifted to match that of its neighbors and hence the optical energy can be redirected.

Exaggerated compensatory response to acute respiratory alkalosis in panic disorder is induced by increased lactic acid production.

BACKGROUND: In acute respiratory alkalosis, the severity of alkalaemia is ameliorated by a decrease in plasma [HCO(3)(-)] of 0.2 mEq/L for each 1 mmHg decrease in PaCO(2). Although hyperventilation in panic disorder patients is frequently encountered in outpatients, the drop in plasma [HCO(3)(-)] sometimes surpasses the expectation calculated from the above formula. The quantitative relationship between reduced PaCO(2) and plasma [HCO(3)(-)] in acute respiratory alkalosis has not been studied in panic disorder patients. Our objective was to provide reference data for the compensatory metabolic changes in acute respiratory alkalosis in panic disorder patients. METHODS: In 34 panic disorder patients with hyperventilation attacks, we measured arterial pH, PaCO(2), plasma [HCO(3)(-)] and lactate on arrival at the emergency room. RESULTS: For each decrease of 1 mmHg in PaCO(2), plasma [HCO(3)(-)] decreased by 0.41 mEq/L. During hypocapnia, panic disorder patients exhibited larger increases in serum lactate levels (mean +/- SD; 2.59 +/- 1.50 mmol/L, range; 0.78-7.78 mmol/L) than previously reported in non-panic disorder subjects. Plasma lactate accumulation was correlated with PaCO(2) (P < 0.001). CONCLUSIONS: These results suggest that the compensatory metabolic response to acute respiratory alkalosis is exaggerated by increased lactic acid production in panic disorder patients. Here, we call attention to the diagnosis of acid-base derangements by means of plasma [HCO(3)(-)] and lactate concentration in panic disorder patients.

[Pulmonary infection of Pneumocystis carinii and Cytomegalo virus in the treatment of cholesterol crystal embolism].

Cholesterol crystal embolism (CCE) is a multivisceral disease caused by occlusion of small arteries with cholesterol crystal emboli deriving from eroded atherosclerotic plaques of the aorta and/or large feeder arteries. The factors precipitating CCE are manipulation of the aorta or other large arteries during arteriography or surgery, and anticoagulant or thrombolytic therapy. CCE has been reported to be a life threatening condition involving multiple vital organ dysfunction, including renal failure, cardiac failure, skin ischemic lesions such as livedo reticularis, patchy skin necrosis, and purple toes, gastrointestinal ischemia, and/or visual disturbance. We report a 63-year-old male patient of CCE after percutaneous transluminal coronary angioplasty, who contracted severe pneumonia of Pneumocystis carinii and Cytomegalo virus during steroid therapy (prednisolone 20 mg for 3 months). He was treated successfully with mechanical ventilation, hemodialysis, and appropriate antibiotic therapy. Although corticosteroid therapy has been reported to be effective in some CCE patients, the indications of steroid therapy, dosage of corticosteroids, duration of the treatment, or efficacy of prophylactic administration of antibiotics are not yet established. Further interventional studies are required in order to evaluate the benefit of corticosteroid therapy for CCE.

Hemodialysis-associated hypotension as an independent risk factor for two-year mortality in hemodialysis patients.

BACKGROUND: The relationship between blood pressure (BP) and mortality in hemodialysis patients has remained controversial. Some studies suggested that a lower pre- or postdialysis BP was associated with excess mortality, while others showed poorer outcome in patients with uncontrolled hypertension. We conducted a multicenter prospective cohort study to evaluate the impact of hemodialysis-associated hypotension on mortality. METHODS: We recruited 1244 patients (685 males; mean age, 60 +/- 13 years) who underwent hemodialysis in 28 units during the two-year study period beginning in December 1999. Pre-, intra-, and postdialysis BP, and BP upon standing soon after hemodialysis, were measured in all patients at entry. Logistic regression analysis was used to assess the effect on mortality of pre-, intra-, and postdialysis BP, a fall in BP during hemodialysis, and a fall in BP upon standing soon after hemodialysis. RESULTS: During the study period, 149 patients died. Logistic models identified the lowest intradialysis systolic blood pressure (SBP) and degree of fall in SBP upon standing soon after hemodialysis as significant factors affecting mortality, but not pre- or postdialysis SBP and diastolic BP. The adjusted odds ratio for death was 0.79 (95% CI 0.64-0.98) when the lowest intradialysis SBP was analyzed in increments of 20 mm Hg, and was 0.82 (95% CI 0.67-0.98) when the fall in SBP upon standing soon after hemodialysis was analyzed in increments of 10 mm Hg. CONCLUSION: These results suggest that intradialysis hypotension and orthostatic hypotension after hemodialysis are significant and independent factors affecting mortality in hemodialysis patients.

Tranexamic acid-induced visual impairment in a hemodialysis patient.

We report a case of overdosage of tranexamic acid (TNA), which was suggested as the cause of visual impairment in a 56-year-old man. He had been undergoing chronic hemodialysis for 1 year, following 10 years of peritoneal dialysis. He had been hospitalized for an emergency operation for a bleeding ulcer of the stomach and duodenum. After the operation, he experienced a gradual loss of sight over about 1 week, although his general condition was good. He received intravenous injections of TNA as a hemostat during hospitalization for the operation. Two weeks after the operation he became blind. Retinography was flat and his visual field had become narrowed. On fluorescein angiography, microgranular hyperfluorescence, which indicated malfunction of the pigmented layer of the retina, was observed. No abnormality of the brain or the optic nerve was shown by magnetic resonance imaging. Concentrations of vitamins and trace minerals in the blood were within the normal ranges. Administration of vitamins A and B(12) did not improve his sight. However, discontinuation of TNA rapidly restored his sight, within a few days. He had received TNA once before because of bleeding ulcer, and his sight had been impaired at that time. Based on the repeated episodes, it was strongly suggested that an overdose of TNA in this dialysis patient caused the sight disturbance. Because TNA is metabolized by the kidney, caution is necessary when prescribing TNA for patients with renal failure.