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We report a neodymium fiber laser incorporating an all-solid photonic bandgap fiber to suppress the four-level laser transition 4F(3/2)-4I(11/2). We demonstrate lasing at 907 nm on the three-level transition 4F(3/2)-4I(9/2) when pumping at 808 nm. The maximum slope efficiency obtained was 32% with a threshold pump power of 70 mW.
A novel method for light coupling between single-mode fibers (SMFs) and small-core photonic crystal fibers (PCFs) is demonstrated. The method is based on growing photopolymer microtips directly on the end faces of SMFs. The shape and size of the tips can be controlled by adjusting the laser power and the exposure time for polymerization to match the mode field to the small-core PCFs. A 5 dB improvement in coupling efficiency between a SMF and a commercial small-core, highly nonlinear PCF is experimentally demonstrated. This compact and efficient butt-coupling method is particularly suitable for PCF gas sensor applications.
We demonstrate a novel method for low-loss splicing small-core photonic crystal fibers (PCFs) and single-mode fibers (SMFs) by repeated arc discharges using a conventional fusion splicer. An optimum mode field match at the interface of PCF-SMF and an adiabatic mode field variation in the longitudinal direction of the small-core PCF can be achieved by repeated arc discharges applied over the splicing joint to gradually collapse the air holes of the small-core PCF. This method is simple and offers a practical solution for light coupling between small-core PCFs and SMFs.
An intracardiac electrophysiologic study was performed in a patient with paroxysmal tachycardia. The patient had two previous episodes of myocardial infarction, but abnormal Q waves were absent in previously obtained electrocardiograms. Electrocardiographic diagnosis of inferior and anterior infarction was made because the electrocardiogram taken on admission temporarily showed abnormal Q waves. Atrioventricular reentry with anterograde conduction over a fasciculoventricular Mahaim fiber and retrograde conduction over a concealed Kent bundle was observed during the tachycardia. It was also demonstrated that electrocardiographic masking of the Q waves was caused by conduction over a fasciculoventricular Mahaim fiber.
The authors report 11 cases of congenital disproportion of fibers, confirmed through clinical and complementary examinations. In these 11 cases early fibrotendinous retractions were frequent and CK proved to be high. At muscle biopsy histochemistry revealed a selective atrophy of type I fibers. This is a rarely frequent congenital dystrophy, of slow progression and benign evolution.
Caffeine contracture in transverse tubules-disrupted (T-disrupted) muscle preparation and the effect of anomalous anions (SCN and NO3) on the contracture in single twitch fibers or thin bundles consisting of 2 or 3 fibers of frog were investigated. The magnitude and the rate of rise of caffeine contracture tension were decreased by T-disruption and the decrease was more marked at lower concentrations of caffeine. No seasonal difference between summer and winter frogs on the effect of T-disruption on caffeine contracture was observed. On the other hand, the magnitude and the rate of rise of caffeine contracture tension in the intact preparation was increased by anomalous anions, whereas the rate of spontaneous relaxation of the contracture was decreased. The effect of SCN on caffeine contracture appeared 5 min after the pre-exposure of muscle preparation of SCN-Ringer solution, with the maximal effect appearing after 10 min. The threshold curve of caffeine contracture was shifted toward the lower caffeine concentrations by anomalous anions and the extent of the shift in the curve was more pronounced with SCN than with NO2. In contrast, the potentiating effect of these anions on the caffeine contracture completely disappeared in T-disrupted muscle preparation. On the basis of these results, the caffeine pathway to the sarcoplasmic reticulum, and the sites and mechanism of the action of anomalous anions on caffeine contracture are discussed.
In the external layer of the median eminence of the fox, the somatostatin-containing fibers and neurophysin-containing fibers of the hypothalamo-infundibular tract are located in distinct areas. In the neural lobe, somatostatin-positive areas are simultaneously neurophysin-positive. Outside the SON and PVN, some somatostatin-positive and neurophysin-negative perikarya are scattered close to the third ventricle. These facts suggest the existence of two somatostatin systems: a hypothalamo-infundibular (neurophysin-negative) one and a hypothalamo-neurohypophyseal (neurophysin-positive) one.
We have registered the contractions of the frog's abdominal muscle in Ringer's solution. The contractions were produced either by acetylcholin or by succinyldicholin. The graphics showed that the succinyldicholin contractions were much slower than the acetylcholin ones. The tracings were not equalized by a preliminary addition of eserin. We conclude that acetylcholine excites the fast fibers and that succinyldicholin excites the slow fibers of the muscle.
Using dispersive and factor analyses of the serial sections of the skeletal muscle tissue it has been shown that the activity of myosin Ca-ATPase is the most essential parameter in the definition of the phenotype of skeletal muscle fiber according to its functional and metabolic characteristics. The stability of this parameter during different functional loadings permits to recommend it as the major one in the definition of the fiber phenotype.
We report a neuropathological case of the brain of a 22-year-old male solvent abuser. He had also been diagnosed as suffering from schizophrenia. Neurohistology revealed the presence of Rosenthal fibers (RFs) in subpial and perivascular collections in the medulla, the floor of the 3rd and 4th ventricles, and also in the spinal cord. There was mild demyelination in the frontal, temporal, and parietal lobes, as well as the left dorsal column in the spinal cord. There was bilateral basal ganglia calcification. Demyelination and RFs have been the hallmark of the diagnosis of adult Alexander's disease. We urge that these are insufficient criteria for this nosological category, and suggest the alternative and more appropriate label of Rosenthal fiber encephalopathy. In view of the known toxic, clinical effects of chronic solvent abuse, and the lack of knowledge of the neuropathological effects, we also tentatively note the association of the solvent abuse with the neuropathology, but are unable to assert any causal link.
The factors inducing normally innervated Schwann cells in peripheral nerve to divide are poorly understood. Transection of the fourth and fifth lumbar ventral roots (L4/5 ventral rhizotomy) of the rat is highly selective, sparing unmyelinated axons and myelinated sensory axons; Wallerian degeneration is restricted to myelinated efferent fibers. We found that L4/5 ventral rhizotomy prompted many normally innervated nonmyelinating (Remak) Schwann cells to enter cell cycle; myelinating Schwann cells of intact (sensory) axons did not. Three days after L4/5 ventral rhizotomy, [3H]thymidine incorporation into Remak Schwann cells increased 30-fold. Schwann cells of degenerating efferents and endoneurial cells also incorporated label. Increased [3H]thymidine incorporation persisted at least 10 d after ventral rhizotomy. Despite Remak Schwann cell proliferation, the morphology of unmyelinated nerve (Remak) bundles was static. Seven days after L5 ventral rhizotomy, Remak Schwann cells in the L5-predominant lateral plantar nerve increased slightly; endoneurial cells doubled. Terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling-positive nuclei increased dramatically in peripheral nerve after L5 ventral rhizotomy; many of these were macrophage nuclei. In summary, we find that the degeneration of myelinated motor axons produced signals that were mitogenic for nonmyelinating Schwann cells with intact axons but not for myelinating Schwann cells with intact axons.
BACKGROUND: Glaucoma is associated with a progressive loss of retinal ganglion cell axons and the evaluation of the thickness of the retinal nerve fibre layer (RNFL) is important for early diagnosis and follow-up. Results of RNFL thickness measurements may vary according to the devices used. Therefore, the present study has analysed and compared the reproducibility of data obtained with three different instruments. METHODS: RNFL thickness was determined using a circular identification line around the optic nerve head by optical coherence tomography (OCT), a Heidelberg Retina Tomograph (HRT) and a Nerve Fiber Analyser (NFA). Each eye was tested six times. The values for RNFL thickness were calculated for the superior, inferior, nasal and temporal areas. A one-way analysis of variance with random effects was chosen to estimate the variance components. The intraclass correlation coefficient (ICC) as a measure of reliability and the coefficient of variation (CV%) as a measure of precision were determined to estimate the reproducibility of RNFL thickness measurements. RESULTS: With all three instruments, the reproducibility of measurements between the superior, inferior, temporal and nasal areas did not differ significantly suggesting that reproducibility does not depend on the thickness of the RNFL. Data obtained by NFA showed the highest ICC values (0.9) and lowest CV% values (7.0), followed by those obtained by HRT (reliability ICC 0.8; precision CV% 12). A markedly lower degree of reproducibility was found for the OCT compared to NFA and HRT (reliability ICC 0.5; precision CV% 15). CONCLUSION: The comparison of RNFL thickness measurements with OCT, NFA, and HRT showed that the NFA yielded the most reliable results followed by HRT.
Reissner's fiber (RF) has been isolated, solubilized, and used to raise polyclonal antibodies. The present investigation has been designed: (1) to obtain antibodies against RF-glycoproteins in their native form (anti-RF-BI), after irreversible denaturation by alkylation (anti-RF-A), and after alkylation and deglycosylation by using endoglycosidase F (anti-RF-DE); (2) to use these antisera for a comparative immunocytochemical study of the subcommissural organ (SCO)-RF complex; (3) to establish the molecular mass of the deglycosylated RF-glycoproteins. Anti-RF-BI reacts with the SCO of all the species investigated. Anti-RF-A and anti-RF-DE only react with bovine SCO and RF. The three antisera stain the same bands in immunoblots of extracts of bovine SCO and RF, but anti-RF-A and anti-RF-DE reveal additional bands. The epitope common to all species reacting with anti-RF-BI is thus probably conformational in nature and associated with the integrity of the disulfide bonds. The lack of antibodies against conserved sequential epitopes in anti-RF-A does not support previous assumptions on the conserved nature of the SCO secretion. After deglycosylation by using endoglycosidase F, the RF-glycoproteins present a reduction in their molecular mass ranging between 10% and 25%. The three larger compounds (450, 300, and 230 kDa) lose their affinity for Limax flavus agglutinin (affinity = sialic acid), whereas the 190-kDa compound (170 kDa after deglycosylation) keeps its affinity for this lectin suggesting that it has N-linked and O-linked carbohydrate moieties, the three larger proteins probably having only N-linked carbohydrates.
An interactive program was described to correct the baseline wandering of the compound action potentials (CAPs) of C-fiber, to calculate the area and the peak amplitude of CAPs, and to analyze their spectral distribution. Using this program, we found the optimal bandpass of the filter for recording CAPs to be from 10 Hz to 3 kHz.
PURPOSE: To compare optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness measurements with established methods for assessment of glaucomatous damage using RNFL photography and visual field testing. DESIGN: Cross-sectional study. PARTICIPANTS: Fifty-eight eyes of 58 healthy volunteer ocular hypertensive patients, glaucoma suspect patients, and glaucoma patients were included. METHODS: Optical coherence tomography 3.4-mm diameter circular scans were obtained within 3 months of RNFL photography and standard achromatic visual field testing. Three independent observers graded RNFL photographs using two standardized protocols. For each method, superior and inferior arcuate bundles were scored separately, and interobserver and intraobserver variation was measured. Standard achromatic visual field mean deviation in the superior and inferior hemifields was compared with RNFL damage as assessed by photography and OCT RNFL thickness measurements. MAIN OUTCOME MEASURES: Visual field mean deviation and severity of glaucomatous RNFL damage as assessed by photography. RESULTS: Optical coherence tomography RNFL thickness decreased with increasing RNFL damage as assessed by photography using both methods of photographic assessment. Standard achromatic perimetry mean deviation was significantly associated with OCT RNFL thickness (R(2) = 35%-43%) and RNFL photography severity score (R(2) = 18%-29%). CONCLUSIONS: These results suggest that the OCT shows promise for providing quantitative measures of RNFL thickness for diagnosing and monitoring glaucoma.
Female SHR mice were fed the activated carbon fiber adsorbent Aqualen beginning at the age of 3 months through their life. Mice were fed Aqualen five times per week together with lab chow at a daily dose of 100 mg/kg b.w. The addition of Aqualen into food did not significantly influence the dynamics of body weight and the mean life-span of the animals. At the same time, the age at 90% mortality of mice was 4 months longer in the group exposed to Aqualen. There were no statistically significant differences in the incidence of all tumors and malignant tumors in the group of mice treated with Aqualen as compared with the control group. However, in the group of mice exposed to Aqualen, there was a 1.4 times reduction of the mean number of tumors per mouse. Feeding mice with the adsorbent led to a 4 months longer life-span in animals with any tumors and to a 5 months longer life-span in animals bearing malignant tumors (P < 0.05). No carcinogenic effect of Aqualen was found. It could be supposed that Aqualen has some geroprotective and anticarcinogenic properties.
Two-month-old outbred female LIO rats were exposed weekly to 15 (experiment I, groups 1, 2 and 3) or to 5 (experiment II, groups 4, 5 and 6) subcutaneous injections of 1,2-dimethylhydrazine (DMH) at a single dose of 21 mg/kg of body weight. From the day of the first injection of the carcinogen, the rats from groups 2, 3, 5 and 6 were given Aqualen in their diet. In both experiments rats were fed Aqualen five times per week together with lab chow at the daily dose of 0.1 g/kg (groups 2 and 5) or 1.0 g/kg (groups 3 and 6) of body weight. Additionally, other rats were not exposed to the carcinogen and served as an intact control (group 7) or were given Aqualen with the diet at the daily dose of 0.1 g/kg (group 8) or 1.0 g/kg (group 9). These experiments were finalized 6 months after the first injection of DMH. In experiments I and II, the majority of tumors were localized in the descending colon. Tumors of the small intestines developed only in rats from experiment I. The total incidence of colon tumors as well as tumors in different parts of the colon and the mean number of tumors per rat were much higher in rats from all groups in experiment I than in the rats from experiment II. In experiment I supplementation of Aqualen to the diet was followed by a decrease in the incidence of tumors in the ascending colon and by a decrease in the number of tumors per rat in both ascending and descending colons regardless of the dose of the enterosorbent. In experiment II the effect of Aqualen was stronger than in experiment I -- the enterosorbent decreased both the tumor incidence and the multiplicity in the total colon, its ascending and descending parts and in the rectum. In experiments I and II the percentage of small colon tumors among rats exposed to Aqualen (groups 2, 3, 5 and 6) was higher than that of the controls (groups 1 and 4). Most of detected intestinal tumors were classified as adenocarcinomas. The level of tumor differentiation was higher in rats exposed to Aqualen. There were no pathological changes observed in rats exposed to Aqualen without DMH. Carcinogen treatment resulted in an increase of serum glucose and cholesterol levels whereas Aqualen normalized these changes. Thus, our results demonstrate the inhibitory effect of activated carbon fiber adsorbent Aqualen on intestinal carcinogenesis in rats.
Hydrophobic cotton fibers, obtained by acylation of cellulose with fatty acid using microwaves radiations, have a high selective affinity for vegetable or mineral oil, fuel, and petroleum, in aqueous medium. Their sorption capacity (SC) (weight of liquid picked up by a given weight of sorbent) is about 20 g/g, after draining. They are reusable after simple squeezing, and their SC reaches a constant value, ca. 12 g/g. Moreover, this product is stable in water, whereas raw cotton can develop molds, after oil sorption. Besides, it is also biodegradable.