High-performance and highly stable 0.3-nm-full-width-at-half-maximum interference optical filters

Fabrication of very-narrow-bandpass optical tunable filters [(0.3 nm full width at half-maximum) (FWHM)] is reported. To improve the film densities, the O(2) ion-assisted deposition-method is used in the fabrication. In the succession of high- and low-refractive-index layers, the commonly used TiO(2) material is replaced by Ta(2)O(5), which suits the ion-assisted fabrication technique. The relative thicknesses of the filter multilayer structure of 1/2/1 are modified to 0.998/2.007/0.998, which reduces the shift difference in the central wavelengths with regard to the p and s polarizations when the filter is tilted. These improvements enabled fabrication of 0.3-nm-FWHM optical tunable filters with improved stability characteristics.     

Ergonomic design and evaluation of the handle for an endoscopic dissector

The purpose of this study was to design an endoscopic dissector handle and objectively assess its usability. The handles were designed with increased contact area between the fingers and thumb and the eye rings, and the eye rings were modified to have a more perpendicular insertion angle to the finger midline. Four different handle models were compared, including a conventional product. Subjects performed dissection, exclusion, grasping, precision manipulation and precision handling tasks. Electromyography and subjective evaluations were measured. Compared to conventional handles, the designated handle reduced the muscle load in the extensor and flexor muscles of the forearm and increased subjective stability. The activity of the first dorsal interosseous muscle was sometimes influenced by the shape of the other parts. The ergonomically designed endoscopic dissector handle used in this study achieved high usability. Medical instrument designs based on ergonomic concepts should be assessed with objective indices.

Practitioner Summary: The endoscopic dissector handles were designed with increased contact area and more suitable insertion angle between the fingers and thumb and the eye rings. Compared to conventional handles, the designated handle reduced the muscle load in the extensor and flexor muscles of the forearm and increased subjective stability.     

Smoking prevalence of female nurses in the national hospitals of Japan

OBJECTIVE: To estimate the prevalence of smoking and the attitudes towards the restriction of smoking at work among female nurses in the national hospitals in Japan. DESIGN: Questionnaires mailed to 14 randomly selected national hospitals and sanitariums in Japan in 1993. SUBJECTS: 2207 female nurses. MAIN OUTCOME MEASURES: Smoking status and history, and attitudes towards the restriction of smoking at work. RESULTS: The prevalence of smoking among female nurses was 18.6%, which was higher than the age-adjusted prevalence of the general female population using this study's subjects as a standardised population. Banning smoking in the hospital in which they worked was supported by 15.0%, whereas 81.6% supported the restriction of smoking. CONCLUSIONS: The results showed that smoking is more common among female nurses than among the general female adult population. The survey suggested that nurses favour restriction, but not banning, of smoking.     

A 4-wavelength optical multi/demultiplexer for WDM subscriber loop systems using analog baseband video transmission

This paper describes the design principles and performance of optical multi/demultiplexers (MUX/DEMUX's) in wavelength-division multiplexing (WDM) subscriber-loop systems over a 50- μm core diameter, graded-index (GI), multimode fiber, which employ analog baseband video transmission using laser diodes (LD's). In this WDM arrangement, requirements for MUX/DEMUX's are: 1) low insertion loss; 2) no signal degradation caused by optical interchannel crosstalk; 3) only a small amount of analog baseband signal degradation caused by the use of MUX/DEMUX; 4) a small size and simple structure capable of multiplexing three or four wavelengths; and 5) good stability. The newly developed 4-wavelength MUX/DEMUX satisfies the preceding requirements and is suitable for application to WDM subscriber-loop systems using analog baseband signals along with digital signals.     

Physiological role of Ca2+-permeable nonselective cation channel in endothelin-1-induced contraction of rabbit aorta

The alpha-amylase of Streptomyces sp. IMD 2679 was subject to catabolite repression. Four different growth rates were achieved when the organism was grown at 40 degrees C and 55 degrees C in the presence and absence of cobalt, with an inverse relationship between alpha-amylase production and growth rate. Highest alpha-amylase yields (520 units/ml) were obtained at the lowest growth rate (0.062 h-1), at 40 degrees C in the absence of cobalt, while at the highest growth rate (0.35 h-1), at 55 degrees C in the presence of cobalt, alpha-amylase production was decreased to 150 units/ml. As growth rate increased, the rate of specific utilisation of the carbon source maltose also increased, from 46 to 123 micrograms maltose (mg biomass)-1 h-1. The pattern and levels of alpha-glucosidase (the enzyme degrading maltose) detected intracellularly in each case, indicate that growth rate effectively controls the rate of feeding of glucose to the cell, and thus catabolite repression.     

Recovery of liquid fuel from hydrocarbon-rich microalgae by thermochemical liquefaction

Liquefaction of Botryococcus braunii, a colony-forming microalga, with high moisture content was performed with or without sodium carbonate as a catalyst for conversion into liquid fuel and recovery of hydrocarbons. A greater amount of oil than the content of hydrocarbons in B. braunii (50 wt% db) was obtained, in a yield of 57–64 wt% at 300 °C. The oil was equivalent in quality to petroleum oil. The recovery of hydrocarbons was a maximum (>95%) at 300 °C.     

Optical multi/demultiplexers for single-mode fiber transmission

This paper describes two types of optical multi/demultiplexers using a single-mode fiber for a two-way transmission system. One type, the filter type, consists of four bandpass filters and a short wavelength pass filter or a long wavelength pass filter. The other, the filter-grating type, consists of two bandpass filters and a grating. The present multi/demultiplexers have four channels with 1.05, 1.15, 1.3, and 1.5 μm wavelengths. Total insertion losses are less than 2.3 and 3.2 dB for the filter type and the filter-grating type, respectively. Cross-talk between channels is less than -40 dB.     

Cylindrical concave diffraction grating utilising thin silicon chip

A unique manufacturing method for concave diffraction gratings is proposed. Also, a cylindrical concave diffraction grating was manufactured with a multimode slab waveguide. A silicon plane diffraction grating was bent cylindrically in this method. The efficiency of the concave diffraction grating was 82% at a 1.3 ?m wavelength. The efficiency was about the same as that of the plane diffraction grating.     

Ultrasonographic findings of diseases in peripheral lung fields using transtracheobronchial endoscopic ultrasonography (TUS)

Cystic neoplasms of the pancreas constitute about 9% of all cystic lesions of the pancreas and less than 1% of all pancreatic neoplasms. The case of a 70 years-old woman with microcystic cystadenoma is reported. CT-scan of the abdomen diagnosed a 5 cm multilocular septated cyst, with calcifications in the context, localized in the head-uncinate process of the pancreas. The mass was well separated by a sharp cleavage plane with portal vein and superior mesenteric vessels. An ERCP showed cephalic symmetrical stenosis (diameter 3 mm) of the main pancreatic duct (MPD), mildly dilated in the remaining tract (diameter 6 mm). An intraoperative biopsy of the cystic wall was performed. Therefore, it was decided to proceed with a duodenum-preserving resection of the head of the pancreas (DPPHR), including the stenosis tract of the MPD in the surgical specimen. The reconstructive procedure consisted, by i.v. jejunal loop transposition, in a side-to-side pancreatico-jejunostomy, including in the anastomosis both corpocaudal stump and the resection cavity of the pancreatic head, and an end-to-side Roux-en-Y jejuno-jejunostomy. With respect to long-lasting pain relief and preservation of the endocrine and exocrine functions of the pancreas, DPPHR is a highly effective surgical procedure with a low early and late morbidity and mortality due to limited surgical resection. This technique, introduced into surgical practice by Beger, is indicated in patients with chronic pancreatitis with an inflammatory mass in the head of the pancreas. The authors conclude that this procedure can be performed also in case of pancreatic benign tumors, as microcystic cystadenoma. Advantages of this technique makes DPPHR an attractive alternative to Pylorus-Preserving-Pancreatico-Duodenectomy (PPPD).