Room-temperature discrete-charge-fluctuation dynamics of a single molecule adsorbed on a carbon nanotube.

Detection and use of physical noise fluctuations in a signal provides significant advantages in the development of bio- and neuro-sensing and functional mimicking devices. Low-dimensional carbon nanomaterials are a good candidate for use in noise generation due to the high surface sensitivity of these materials, which may themselves serve as the main building blocks of these devices. Here, we demonstrate that the addition of a molecule with high redox activity to a carbon nanotube (CNT) field-effect transistor provides tunable current fluctuation noise. A unique charge-trap state in the vicinity of the CNT surface due to the presence of the single molecule is the origin of the noise, which generates a prominent and unique slow discrete random telegraph signal in the device current. The power spectral density reveals the peculiar frequency limit of the fluctuation for different types of molecules depending on their redox activity and adsorption configuration. These results indicate that the detected noise will provide new opportunities to obtain electronic information for a single molecule combined with a nanotube surface, and that controllability of the noise may contribute to the expansion of noise utilization in future bio-inspired devices.

Nosocomial Serratia marcescens outbreak in Osaka, Japan, from 1999 to 2000.

OBJECTIVES: To investigate and control an outbreak of bloodstream infections (BSIs) caused by Serratia marcescens and to identify risk factors for respiratory colonization or infection with S. marcescens. DESIGN: Epidemiologic investigation, including review of medical and laboratory records, procedural investigations, pulsed-field gel electrophoresis (PFGE) typing of environmental and patient isolates, statistical study, and recommendation of control measures. PATIENTS AND SETTING: All patients admitted to a 380-bed, secondary-care hospital in Osaka Prefecture, Japan, from July 1999 through June 2000 (study period). RESULTS: Seventy-one patients were colonized or infected with S. marcescens; 3 patients who developed primary BSIs on the same ward within 5 days in June 2000 had isolates with indistinguishable PFGE patterns and indwelling intravenous catheters for more than 5 days. On multivariate analysis, among 36 case-patients with positive sputum specimens and 95 control-patients, being bedridden (odds ratio [OR], 15.91; 95% confidence interval [CI95], 4.17-60.77), receiving mechanical ventilation (OR, 7.86; CI95, 2.27-27.16), being older than 80 years (OR, 3.12; CI95, 1.05-9.27), and receiving oral cleaning care (OR, 3.10; CI95, 1-9.58) were significant risk factors. S. marcescens was isolated from the fluid tanks of three nebulizers and a liquid soap dispenser. The hospital did not have written infection control standards, and many infection control practices were found to be inadequate (eg, respiratory equipment was used without disinfection between patients). CONCLUSIONS: Poor hospital hygiene and the lack of standard infection control measures contributed to infections hospital-wide. Recommendations to the hospital included adoption of written infection control policies.

Late-onset familial amyloid polyneuropathy: an autopsy study of two Japanese brothers.

We report an autopsy study of late-onset familial amyloid polyneuropathy with a variant transthyretin Val30Met in 2 brothers living in Kyoto, Japan. The disease onsets were at 64 and 59 years, and they died at 71 and 74 years old, respectively. They exhibited almost the same postmortem findings. Amyloid deposition was remarkable in the hearts, but was not seen in the renal glomeruli. In the peripheral nervous system, amyloid deposition was most prominent in the nerves immediately caudal to ganglia, moderate in the dorsal and sympathetic ganglia, and mild in the spinal roots, sciatic nerves, and distal nerves. The difference between the amyloid deposition in the proximal portion and distal portion of the extremity nerves appeared to be greater in the late-onset type than in the ordinary type, and this proximal deposition of amyloid may have induced severe distal nerve fiber degeneration.

Leber's hereditary optic neuropathy with intracranial arteriovenous malformation: a case report.

We reported a patient with Leber's hereditary optic neuropathy (LHON) with an intracranial arteriovenous malformation (AVM). Genetic analysis of this patient revealed a point mutation in mitochondrial DNA (mtDNA) at nucleotide position 11,778 in the ND4 subunit of complex I. Although the relationship between intracranial AVM and mtDNA mutations remains uncertain, some patients with intracranial AVM may be associated with mitochondrial abnormality. Further study is necessary to confirm whether the above conditions are coincidental or closely interrelated.

Evaluation of a sentinel surveillance system for influenza, 1995-2000, Kyoto City, Japan.

We compared a municipal sentinel surveillance system for influenza with the Microbial Isolation Surveillance System (MISS) in Kyoto City, Japan. Sensitivity, specificity, and predictive value positive (PVP) of the Influenza Sentinel Surveillance System (ISSS) compared to the MISS were calculated by influenza season and by month. Sensitivity ranged from 80 to 97%, specificity ranged from 55 to 77%, and PVP ranged from 29 to 52% by season (P < 0.001). On the other hand, sensitivity ranged from 86 to 100%, specificity ranged from 38 to 66%, and PVP ranged from 31 to 50% by month (P < 0.001). Specificity was calculated as 93% in November. The sensitivity of ISSS was found to be sufficient regardless of the magnitude of influenza activity. Specificity varied by season, indicating the difficulty of clinically diagnosing other respiratory illnesses. The PVP remained at less than 50% before and after the influenza seasons and it varied year by year. In general, the ISSS is a good surveillance system for monitoring influenza activity.