An efficient 0.04-nm apodized fiber Bragg grating and its application to narrow-band spectral filtering

A narrow-band apodized fiber Bragg grating was fabricated with a phase mask method that incorporated a fluorescence monitoring technique. The grating length was 100 mm and the 3-dB reduced bandwidth was as small as 0.04 nm. The 20-dB reduced bandwidth was 0.1 nm at a center wavelength of 1554 mm. A single longitudinal oscillation mode of a 10-GHz pulse train from a mode-locked fiber laser was successfully extracted using the grating.     

Infinite-distance soliton transmission with soliton controls in time and frequency domains

It is shown by computer runs and simple analysis that one hundred million km soliton transmission is possible by means of soliton transmission controls in the time and frequency domains. This means that limitless transmission is possible. The key to success is to reduce noise by the synchronous modulation technique which can also reduce timing jitter and nonlinear interaction forces. The accumulated noise converges to a fixed low level even after limitless transmission.<>     

Vascular effects of endothelin-1 in stage 21 chick embryos

Endothelin-1 is a very potent vasoconstrictor, but its function has not yet been investigated in the early stage of cardiovascular development. The purpose of the present study was to clarify whether endothelin-1 exerts a hemodynamic effect in stage 21 chick embryos. We measured vitelline artery blood pressure with a servo-null micropressure system and blood flow velocity at the dorsal aorta with a 20 MHz pulsed Doppler velocity meter. The vitelline vessels were directly measured with a microscope video system. While monitoring these parameters, endothelin-1 was infused into a vein by a microinjector and data were collected. Endothelin-1 increased the blood pressure and heart rate, but decreased the dorsal aortic blood flow. Only the vitelline veins with a diameter of between 100 and 200 microm constricted after endothelin infusion, but smaller or larger veins and the arteries did not show any significant change in size, although the resistant arteries could not be measured by this method. In conclusion, endothelin-1 has apparent constrictive effects in the selected vessel in the early stages of cardiovascular development when the endocrine and autonomic nervous systems have not yet developed.     

Quantitative detection of ultraviolet-specific p53 mutations in normal skin from Japanese patients

The production and evaluation of non-radioactive probes for the detection of 'Candidatus Liberobacter asiaticum' and 'Candidatus Liberobacter africanum', the two bacterial species associated with citrus huanglongbing (greening) disease is described. Two DNA fagments, In 2.6 and AS 1.7, obtained previously from the beta operons of 'Candidatus Liberobacter asiaticum' and 'Candidatus Liberobacter africanum', respectively, were the starting materials for production of the two non-radioactive probes. These digoxigenin (DIG)-labelled probes were generated by PCR incorporation of DIG-11-dUTP, yielding In 1.7-DIG and AS 1.7-DIG. Probe In 1.7-DIG was hybridized with DNAs extracted from 24 field-collected samples in Bali (Indonesia). The membrane on which the DNAs were blotted was first hybridized with radioactive probe 32P-In 2.6. After the hybridization results were recorded, the radioactive probe was removed, and the membrane hybridized with DIG-labelled probe In 1.7-DIG. Identical results were obtained for 23 samples. One sample was positive with the DIG-labelled probe and negative with the 32P-labelled probe. However, cross-hybridization of In 1.7-DIG with DNA from L. africanum was higher than that obtained with the radioactive probe. This cross-hybridization could be eliminated by raising the temperature of the stringent washing step. No field samples from Africa being available, probe AS 1.7-DIG was dot-blot hybridized against DNAs extracted from leaves of greenhouse-kept citrus plants from different geographical origins and infected with one or other Liberobacter species. The data showed that AS 1.7-DIG hybridized with L. africanum with a sensitivity equivalent to that of the radioactive probe.     

Viral respiratory infection causes airway hyperresponsiveness and decreases histamine N-methyltransferase activity in guinea pigs

We investigated the effects of viral respiratory infection by Sendai virus on bronchial responses to aerosolized histamine in anesthetized guinea pigs and on the activity of histamine N-methyltransferase (HMT). We measured the change in total pulmonary resistance induced by histamine in the presence or absence of a specific HMT inhibitor, SKF 91488, in noninfected and infected animals. In the absence of SKF 91488, the bronchoconstrictor response to histamine was greater in infected than in noninfected animals. SKF 91488 (10(-2) M, 90 breaths) potentiated the responses to histamine in noninfected animals, and the magnitude of augmented responses to histamine by SKF 91488 was similar to that by viral infection. Furthermore, SKF 91488 did not further potentiate the responses to histamine in infected animals. However, responses to aerosolized acetylcholine were unaffected by viral infection and SKF 91488. The HMT activity decreased by 56% in the trachea, 86% in the bronchi, and 52% in the parenchymal tissue in the infected animals. In contrast to HMT activity, acetylcholinesterase activity was unaffected by viral infection. These results suggest that respiratory infection by Sendai virus causes enhanced bronchial responsiveness to histamine by decreasing HMT activity in airways.     

Simultaneous determination of five macrolide antibiotics in meat by high-performance liquid chromatography

A simple and rapid method using high-performance liquid chromatography (HPLC) for the simultaneous determination of five macrolides (josamycin, kitasamycin, mirosamicin, spiramycin and tylosin) in meat has been developed. The drugs were extracted with 0.3% metaphosphoric acid-methanol (7:3, v/v), and the extracts were cleaned up on a Bond Elut SCX (500 mg) cartridge. The HPLC separation was performed on a Puresil 5C18 column (150 x 4.6 mm I.D.) with a gradient system of 0.025 M phosphate buffer (pH 2.5)-acetonitrile as the mobile phase at a flow-rate of 1.0 ml/min. The drugs were detected at 232 mn for josamycin, kitasamycin, mirosamicin and spiramycin, and 287 mn for tylosin. The calibration graphs were rectilinear from 2.5 to 100 ng for each drug. The recoveries at the level of 1.0 microgram/g were 70.8-90.4%, and detection limits were 0.05 microgram/g for each drug.     

Immunohistochemical localization of peroxisomal enzymes in developing rat kidney tissues

We studied the developmental changes in the localization of peroxisome-specific enzymes in rat kidney tissues from embryonic Day 16 to postnatal Week 10 by immunoblot analysis and immunohistochemistry, using antibodies for the peroxisomal enzymes catalase, d-amino acid oxidase, l-alpha-hydroxyacid oxidase (isozyme B), and enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase bifunctional protein. Peroxisomal enzymes were detected in the neonatal kidney by immunoblot analysis and their amount increased with kidney development. By light microscopic immunohistochemistry, they were first localized in a few proximal tubules in the juxtamedullary cortex of 18-day embryos. The distribution of proximal tubules positive for them expanded towards the superficial cortex with development. The full thickness of the cortex became positive for the staining by 14 days after birth. Peroxisomes could be detected by electron microscopy in structurally immature proximal tubules in 18-day embryos. Their size increased and the ultrastructure of subcompartments became clear with continuing development of proximal tubules. These results show that peroxisomal enzymes appear in the immature proximal tubules in the kidney of embryos and that the ultrastructure of the peroxisomes and localization of the peroxisomal enzymes develop along with the maturation of proximal tubules and kidney tissues.     

p53 accumulation and apoptosis in embolized meningiomas

Preoperative embolization of meningiomas is performed to decrease blood loss at surgery. While it is also expected to reduce tumor recurrence by producing necrosis at the site of dural attachment, very little has been described about what happens to the non-necrotic tumor cells. We investigated how the proliferative activities of meningiomas were modified after embolization. In nine meningiomas which were embolized preoperatively, proliferative potentials and expression of cell cycle inhibitors were assessed immunohistochemically using MIB-1, anti-53 (DO-1 and DO-7), and anti-p21 (WAF1/CIP1) monoclonal antibodies. To determine whether a cell underwent apoptotic death besides necrosis, we applied the terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling method. Results were compared with control meningiomas without embolization. MIB-1 positive cells often gathered in perinecrotic areas, although the mean MIB-1 staining index of the embolized meningiomas was not significantly different from the control. p53 and its downstream effector p21 accumulated mainly in the perinecrotic areas in eight of the nine embolized meningiomas. Apoptosis was also observed in the concomitant areas. Double staining for both MIB-1 and p21 frequently showed positive cells for both antibodies. The accumulation of MIB-1 positive cells in the embolized meningiomas may not be a sign of fast growth or malignancy, but it may implicate arrest of cell cycle by the p21. This study indicates that embolized meningiomas exhibit not only necrosis but also apoptosis and cell cycle arrest. The latter effects appear to be at least partly p53 dependent.     

Photon probe fault locator for single-mode optical fiber using an acoustooptical light deflector

A new backscattering technique for diagnosing the attenuation characteristics, spatial imperfections with length (fault location), and splice loss in a single-mode optical fiber has been developed by using a TeO2acoustooptical light deflector operating at 120 MHz. Due to the small insertion loss and high extinction ratio of the deflector, the dynamic range of the backscattered signal has been increased by at least 10 dB, which corresponds to the extension of 5 km in measurable length for fiber loss of 1 dB/km, compared with the conventional back-scattering technique in which the beam splitter and polarizer-analyzer combination are utilized. Another advantage of this technique is in that the saturation of the amplifier is avoided by arbitrarily cutting off a large power in the early stage of the Rayleigh scattering signal. A single-mode fiber of 19.2 km in length has been examined, and the distance for fault location up to 18.4 km was obtained.     

A Decomposition Method for Computing System Reliability by a Matrix Expression

A decomposition method using a matrix representation for computing the reliability of a redundant system is proposed. The system is decomposed into two subsystems according to up- and down- states of a keystone element. This is repeated recursively until all subsystems have known reliability. The criterion for choosing the keystone element and an algorithm for decomposing a system are described.