Gap function with point nodes in borocarbide superconductor YNi2B2C

To determine the superconducting gap function of YNi2B2C, the c-axis thermal conductivity kappa(zz) was measured in H rotated in various directions. The angular variation of kappa(zz) in H rotated within the ab plane shows a peculiar fourfold oscillation with narrow cusps. The amplitude of this fourfold oscillation becomes very small when H is rotated conically around the c axis with a tilt angle of 45 degrees. These results provide the first compelling evidence that the gap function has point nodes located along the a and b axes. This unprecedented gap structure challenges the current view on the pairing mechanism.

Antiferromagnetic order induced by an applied magnetic field in a high-temperature superconductor

One view of the high-transition-temperature (high-Tc) copper oxide superconductors is that they are conventional superconductors where the pairing occurs between weakly interacting quasiparticles (corresponding to the electrons in ordinary metals), although the theory has to be pushed to its limit. An alternative view is that the electrons organize into collective textures (for example, charge and spin stripes) which cannot be 'mapped' onto the electrons in ordinary metals. Understanding the properties of the material would then need quantum field theories of objects such as textures and strings, rather than point-like electrons. In an external magnetic field, magnetic flux penetrates type II superconductors via vortices, each carrying one flux quantum. The vortices form lattices of resistive material embedded in the non-resistive superconductor, and can reveal the nature of the ground state-for example, a conventional metal or an ordered, striped phase-which would have appeared had superconductivity not intervened, and which provides the best starting point for a pairing theory. Here we report that for one high-Tc superconductor, the applied field that imposes the vortex lattice also induces 'striped' antiferromagnetic order. Ordinary quasiparticle models can account for neither the strength of the order nor the nearly field-independent antiferromagnetic transition temperature observed in our measurements.

Fermi surface sheet-dependent superconductivity in 2H-NbSe2

High-resolution angle-resolved photoemission spectroscopy was used to study the superconducting energy gap and changes in the spectral function across the superconducting transition in the quasi-two-dimensional superconductor 2H-NbSe2. The momentum dependence of the superconducting gap was determined on different Fermi surface sheets. The results indicate Fermi surface sheet-dependent superconductivity in this low-transition temperature multiband system and provide a description consistent with thermodynamic measurements and the anomalous de Haas-van Alphen oscillations observed in the superconducting phase. The present data suggest the importance of Fermi surface sheet-dependent superconductivity in explaining exotic superconductivity in other multiband systems with complex Fermi surface topology, such as the borides and f-electron superconductors.

[Changes in the prevalence of asthma-like symptoms and risk factors in school children in Yokohama from 1986 to 1991]

We conducted a questionnaire survey of first graders from six elementary schools in three areas of Yokohama annually from 1986 to 1991 (about 700 children each year) to investigate the changes in prevalence of asthma-like symptoms and association with potential risk factors. The prevalence rate of asthma-like symptoms increased from 7.6% to 11.0% in boys and from 6.5% to 8.8% in girls from 1986 to 1991. The ratio of affected boys was consistently higher than that in girls, but there were no significant regional differences. We found statistically significant odds ratios for the effect of a previous history of allergies, respiratory disease before age two, wheezing or difficulty in breath before age two and cough without respiratory tract infections on the prevalence of asthma-like symptoms.

[The relationships between the prevalence of asthmatic symptoms and environmental factors]

The relationships between the prevalence of asthmatic symptoms and environmental factors were evaluated using a modified version of the Japanese ATS-DLD children's questionnaire. The questionnaire was distributed to 13,306 students in 3 areas of Yokohama City; in 1986 (4705), 1988 (4440), and 1991 (4161). The results indicate: 1. The prevalence of asthmatic symptoms among boys increased slightly from 1986 (9.2%) to 1991 (9.6%), but no increase was observed that among girls (5.7%). The overall prevalence among boys was 1.7 times higher than that among girls. 2. On the whole, the air pollution level was Tsurumi-ku > Naka-ku > Midori-ku. But the prevalence of asthmatic symptoms among boys was Naka-ku > Tsurumi-ku > Midori-ku in 1986, 1988 and 1991. The prevalence among girls was the same result in 1986, but in 1988 and 1991, it was Tsurumi-ku > Naka-ku > Midori-ku. 3. In the longitudinal study of the same group, the prevalence of asthmatic symptoms among boys decreased between 5th and 6th grade. In contrast, remission of asthma increased between 5th and 6th grade. And the prevalence of asthmatic symptoms among girls decreased between 3rd and 6th grade. In contrast, remission of asthma increased between 3rd and 6th grade. 4. Children who had a personal or family history of allergic diseases, allergic disposition, respiratory diseases before 2 years old, wheezing or difficulty in breathing, or allergies against foods or medicines, showed a statistically significant Odds ratio (p < 0.01) for asthmatic symptoms.

Spins in the vortices of a high-temperature superconductor

Neutron scattering is used to characterize the magnetism of the vortices for the optimally doped high-temperature superconductor La(2-x)Sr(x)CuO4 (x = 0.163) in an applied magnetic field. As temperature is reduced, low-frequency spin fluctuations first disappear with the loss of vortex mobility, but then reappear. We find that the vortex state can be regarded as an inhomogeneous mixture of a superconducting spin fluid and a material containing a nearly ordered antiferromagnet. These experiments show that as for many other properties of cuprate superconductors, the important underlying microscopic forces are magnetic.

Ultrahigh-resolution photoemission spectroscopy of Ni borocarbides: direct observation of the superconducting gap and a change in gap anisotropy by impurity

We have performed ultrahigh-resolution photoemission spectroscopy of Y(Ni1-xPtx)2B2C ( x = 0.0 and 0.2) in order to study the changes in the density of states across the superconducting transition. Because of a drastic increase in energy resolution, we clearly observe the opening of superconducting gaps across T(c) in both compounds. Furthermore, we find a small but significant difference in the superconducting-state spectral shape. This can be explained in terms of reduction in gap anisotropy by introducing impurities and provides spectroscopic evidence for an anisotropic s-wave gap in YNi2B2C.

The health care system for female workers and its current status in Japan

In this paper we describe female workers' health care, the women's and maternal protection system within the Japanese legal system, the current status of female workers in Japan, and problems regarding methods of advancing health care and the women's or maternal protection system. Motherhood is respected in the workplace in Japan, and in order to provide an environment in which women can work and still bear and rear children with a sense of security, laws concerning maternal protection of female workers, and revisions in terms of the system have been made, and a new system has been in effect since the fiscal year of 1998. Nevertheless, gender discrimination against women and the disparagement of women, rooted in gender role stereotypes concerning the division of labor, remain firmly planted in the social environment and in long-established custom.

[A case of giant sebaceous gland carcinoma without adequate treatment]

BACKGROUND

A patient with a sebaceous gland carcinoma without adequate treatment is reported.

CASE

A 67-year-old man underwent an operation on his left upper eyelid after a diagnosis of chalazion in 1981. Two years after the initial operation, he noticed a tumor in the left upper eyelid. In 1987, he visited another hospital and was diagnosed with sebaceous gland carcinoma by a tissue biopsy. He left it untreated against medical advice. When he visited our hospital in 1996, the tumor was as large as 80 x 75 x 40 mm and the left upper and lower eyelids stuck together. After admission, he died of myocardial infarction 23 days after his visit to our hospital. Autopsy revealed that the tumor had extended into the orbital cavity, paranasal sinus, and base of the skull, with metastasis to the preauricular, submandibular, and cervical lymph nodes and both lungs. The pathology of the tumor was a moderately differentiated sebaceous gland carcinoma.

CONCLUSION

This case showed the natural course of extension and metastasis of a sebaceous gland carcinoma.

LiV2O4 spinel as a heavy-mass fermi liquid: anomalous transport and role of geometrical frustration

Transport and specific heat measurements on hydrothermally grown single crystals reveal the formation of a heavy-mass Fermi liquid in the LiV2O4 spinel, below a coherence temperature of T* = 20-30 K. A few observations which illustrate the uniqueness of this spinel are discussed in connection with the origin of the heavy mass, such as the anomalous absence of resistivity saturation above T* and the close proximity to a spin glass phase where the influence of the magnetic frustration is evident.

Altered calcium handling in compensated hypertrophied rat cardiomyocytes induced by pressure overload

To investigate Ca2+ handling in compensated hypertrophied cardiomyocytes, we measured Ca2+ transients and contraction of hypertrophied rat left ventricular myocytes induced by aortic constriction (AC). The fluorescence ratio (I405/I480) after indo-1/AM loading and circumferential length were simultaneously measured in isolated myocytes. The amplitude of Ca2+ transients (Ca-Amp) was higher in rats with AC than in sham-operated rats (Sham) (0.25 +/- 0.08 vs 0.17 +/- 0.05). There was a positive correlation between Ca-Amp and fractional shortening (FS) in both AC and Sham rats, whereas the ratio of FS/Ca-Amp was smaller in AC rats. These observations suggest that compensated hypertrophied cardiomyocytes exhibit an adaptive increase in Ca-Amp, associated with reduced myofilament responsiveness to an increase in Ca2+. Isoproterenol and forskolin increased Ca-Amp and FS, and decreased time to 50% decline of Ca2+ transients. Although myocytes from AC rats exhibited reduced responsiveness to isoproterenol, responses to forskolin did not differ between the 2 groups. The reduced beta-adrenergic response in Ca2+ handling was probably due to altered beta-adrenoceptor numbers, G-protein function and/or their coupling process.

Partial characterization of the gametes and development of a successful in vitro fertilization procedure in the mastomys (Praomys coucha): a new species for reproductive biology research

The mastomys, a small African rodent, has been extensively used as a laboratory animal for cancer research. Previous preliminary studies have demonstrated that the animal has a relatively short estrous cycle and that superovulation can be induced. However, biological characterization of the gametes in this species has not been done. The purpose of this study is to determine requirements for fertilization and to devise a suitable method for in vitro fertilization (IVF). Data from these studies show that 1) cauda epididymal plasma (CEP) is required for maintaining sperm motility in vitro; 2) in a heterologous sperm penetration assay in vitro, optimal conditions for sperm capacitation and the acrosome reaction depend on time and CEP concentration; and 3) loss of the cortical granules is observed to occur spontaneously within 3-4 h after ovulation in superovulated eggs. On the basis of the data obtained from these studies, we have developed a method for preincubation of mastomys sperm and a successful mastomys IVF procedure. This species can now be used as a new laboratory animal for research in reproductive biology.

Electron microscopic immunohistochemistry of ocular and extraocular pseudoexfoliative material

To investigate the nature of extraocular pseudoexfoliative (PSX) material, and to validate the hypothesis that the PSX syndrome is a systemic disorder, we studied the immunoreactivity of intraocular and extraocular PSX material from patients with the PSX syndrome using antibodies against proteins of extracellular matrices. Surgical specimens of four different tissues were obtained from human eyes with the PSX syndrome: nine trabecular tissues, three cataractous lenses, six bulbar conjunctivas, and seven lid skins. These tissues were processed for electron microscopic immunohistochemistry, and stained with antibodies against vitronectin, fibronectin, laminin, and elastin, by an indirect immunogold procedure. Density of the gold particles located on the PSX material was estimated by video image analysis. Statistical analysis of the data revealed that the PSX material from trabecular tissues, lenses, bulbar conjunctivas, and lid skins had almost identical immunoreactivity to the antibodies studied. PSX materials of trabecular tissues, lenses, bulbar conjunctivas, and lid skins were found to have not only a similar ultrastructure, but also almost identical immunohistochemical characteristics. These results support the hypothesis that the PSX syndrome is a systemic disorder.

Ocular symptoms due to organophosphorus gas (Sarin) poisoning in Matsumoto

Images

Preschool boys and girls use no differently

Twenty-one videotape recorded interactions of 42 preschool children (aged 3;4 to 5;3) in same-sexed dyads were coded and analysed to see how these children used the word no in their interactions. Results showed that while boys and girls used the word no equally frequently, they were found to use the word in different ways. A trend for boys to use no when correcting or prohibiting their playmate's behaviour more often than girls was revealed. Girls were more likely to provide reasons for denying or rejecting their playmate's proposition or suggestion. The overall findings of this study are comparable to previously reported results indicating that males and females employ different styles of speech in order to accomplish the same goal. However, unlike most studies conducted on language and sex, this study offers a unique approach in that it examines how boys and girls use a word that occurs equally frequently in their vocabulary to accomplish different goals.

Sarin poisoning in Matsumoto, Japan

A presumed terrorist attack with sarin occurred in a residential area of the city of Matsumoto, Japan, on June 27, 1994. About 600 residents and rescue staff were poisoned; 58 were admitted to hospitals, and 7 died. We examined clinical and laboratory findings of 264 people who sought treatment and the results of health examinations on 155 residents done 3 weeks after the poisoning. Findings for severely poisoned people were decreases in serum cholinesterase, acetylcholinesterase in erythrocytes, serum triglyceride, serum potassium and chloride; and increases in serum creatine kinase, leucocytes, and ketones in urine. Slight fever and epileptiform abnormalities on electroencephalogram were present for up to 30 days. Examination revealed no persisting abnormal physical findings in any individual. Acetylcholinesterase returned to normal within 3 months in all people examined. Although subclinical miosis and neuropathy were present 30 days after exposure, almost all symptoms of sarin exposure disappeared rapidly and left no sequelae in most people.

Electron microscopic lectin histochemistry of the trabecular meshworks in human eyes

Ten normal human trabecular meshworks were examined by electron microscopy using avidin-biotin complex in order to investigate the localization of binding sites of eight lectins. The tissue specimens were fixed in paraformaldehyde and glutaraldehyde mixture and embedded in Lowicryl K4M at low temperature. The ultrathin sections were stained with biotin labelled lectins and colloidal gold labelled streptoavidin and were observed with the conventional transmission electron microscope. Some lectins such as ABA, ConA and DSA were localized on fine fibrils underneath the endothelium of the trabecular wall of the Schlemm's canal, electron-dense cores of elastic fibers, fine granular like materials, basement membranes, collagen fibers and the long-spacing fibers. However, the other lectins such as DBA, SBA, Lotus, UEA-I and RCA60 were not specifically localized in these tissues. From the results it was demonstrated that the differential ultrastructural localization of glycoconjugate residues in the human trabecular meshworks can be revealed using this lectin staining.

Vogt-Koyanagi-Harada disease during pregnancy

Images

Lectin electron microscopic histochemistry of the pseudoexfoliative material in the skin

PURPOSE

To investigate the hypothesis that pseudoexfoliation (PSX) syndrome is a systemic disorder, the authors studied the composition of glycoconjugates in the intraocular and extraocular PSX material at the electron microscopic level, using a panel of lectins as cytochemical probes.

METHODS

The authors examined 8 lid skins, 11 trabecular tissues, and 3 cataractous lenses from human eyes with PSX syndrome. Tissues were processed for electron microscopical histochemistry and stained with PNA, RCA120, DBA, SBA, ConA, WGA, UEA-I, and Lotus, with an indirect lectin-colloidal gold technique.

RESULTS

Both the intraocular and extraocular PSX materials manifested almost identical reactivity to lectins, which indicated that glycoconjugates in the PSX material contained with sugar residues of galactose (PNA, RCA120), alpha-mannose (ConA), and N-acetyl-D-glucosamine (WGA). On the other hand, it was indicated that sugar residues of N-acetyl-D-galactosamine (DBA, SBA) and fucose (UEA-I, Lotus) were absent. Granular inclusions and microfibrils in the capsule and ocular zonules were stained similarly and weakly.

CONCLUSIONS

The intraocular and extraocular PSX materials contained the same sugar residues of glycoconjugates, which suggested that those materials had the same nature. This study, the first documentation of lectin-binding sites on the extraocular PSX material, supported the hypothesis of PSX syndrome as a systemic disorder.

Cumulus mass maintains embryo quality

OBJECTIVE

To determine if co-culture of early stage embryos with their own cumulus mass improves embryo quality.

DESIGN

Before insemination, cumulus masses along with cumulus matrices were separated from the oocytes surrounded by a few remaining cumulus cells. Fourteen hours after insemination, fertilized oocytes were each placed onto the cumulus cells, and matrix and co-culture commenced. The embryos were observed every 24 hours. Fifty-three oocytes were treated in co-culture (C) and 59 oocytes were treated in routine culture (U).

RESULTS

Thirty-four (C) and 43 (U) oocytes were fertilized and placed on growth media for further culture. Twenty-four hours after culture, 10 embryos (29%) in C and 12 (28%) in U were good quality, and 4 embryos (12%) in C and 7 (16%) in U were of poor quality. Seventy-two hours after culture, 10 (29%) in C and 8 (18%) in U were of good quality, and 3 (9%) in C and 13 (30%) were of poor quality. The percentage of good quality embryos in the co-culture group was significantly higher than in the control group after 72 hours. Conversely, the percentage of poor quality embryos in the co-culture group was significantly lower than that in the control group after 72 hours.

CONCLUSION

Co-culture maintains embryo quality over prolonged culture times. This facilitates the development of good quality embryos for ET.

Localization of elastin in the normal and glaucomatous human trabecular meshwork

PURPOSE

The extracellular materials (ECMs) in the trabecular meshwork (TM) are thought to play a crucial role in aqueous outflow resistance. Immunohistochemical localization of elastin, one of the major ECMs in the normal and glaucomatous human TM, was examined ultrastructurally.

METHODS

Eight normal eye bank eyes and 16 trabeculectomy specimens of primary open angle glaucoma (POAG, 11 eyes from 8 cases), congenital glaucoma (2 eyes from 1 case), and juvenile glaucoma (3 eyes from 2 cases) were embedded in Lowicryl K4M at low temperature. The distribution of elastin was studied by the protein A-gold technique.

RESULTS

In normals, the gold particles indicating the antigenic sites for elastin existed mainly in the central amorphous element of the elastic-like fibers, and a few gold particles were observed within the area containing fine granular-like material and fine fibrillar-like material. No labeling was observed in cellular materials or other ECMs. In congenital and juvenile glaucoma, labeling was similar to that observed in normals. In POAG specimens compared to normals, there was an increased amount of elastin-bound immunogold particles along the inner canal endothelium. The increased gold particles, which did not have a fibrillar arrangement and were not enclosed by electron-dense microfibrils, were found within the area containing fine fibrillar-like material. However, labeling within the elastic-like fibers was similar to that observed in normals.

CONCLUSIONS

Under electron microscopy, elastin could be localized in the normal and glaucomatous human TM. The results of this investigation suggest that elastin may play an important role in the etiology of POAG.

Dominance of activated T cells and interleukin-6 in aqueous humor in Vogt-Koyanagi-Harada disease

PURPOSE

To determine the immunopathologic role of the lymphocytes and lymphokines in aqueous humor (AH) of patients with Vogt-Koyanagi-Harada disease (VKH).

METHODS

The distribution of leukocyte subsets in the peripheral blood and AH was examined using fluorescein isothiocyanate-conjugated monoclonal antibodies. The levels of lymphokines, such as interleukin-2 (IL-2) and interleukin-6 (IL-6), in the sera, AH, and cerebrospinal fluid from the patients with VKH were determined using an enzyme-linked immunosorbent assay.

RESULTS

T cells constituted the majority of lymphocytes within AH. The value for CD4+ cells (helper/inducer T lymphocytes) in AH was 51.7% +/- 14.9% (mean +/- SD) and that for CD8+ cells (cytotoxic/suppressor T lymphocytes) was 31.1% +/- 13.0%. The percentage of HLA-DR+ cells (B lymphocytes, monocytes, macrophages, and activated T lymphocytes) in AH (50.8% +/- 24.9%) significantly exceeded (P < 0.001) that in blood (13.1% +/- 4.2%). The percentage of CD8+ cells in AH from three patients with the delayed type of VKH rose during their clinical course. The level of IL-6 was significantly elevated in AH from the patients with VKH. The level of IL-6 in AH correlated with the number of lymphocytes in AH, and it reflected the severity of the inflammatory response in AH of patients with VKH. The level of IL-2 in the sera, AH, and cerebrospinal fluid was in the normal range.

CONCLUSIONS

Aqueous humor lymphocytes from the patients with VKH were more activated than were peripheral blood lymphocytes. IL-6 may play an important role as an inflammatory mediator in VKH. It may be useful to analyze the lymphocyte subsets and the levels of lymphokines, especially of IL-6, at the site of inflammation in uvea to improve the criteria for assessing the prognosis of VKH.

[Lectin histochemical studies on species differences in the mammalian trabecular meshwork]

Lectin histochemical studies were performed to clarify the species differences in the location of glycoconjugates in the trabecular meshwork (TM) of various mammals, i.e., the mouse, rat, rabbit, pig, and ox, to find an experimental model for human TM. Cryosections were made and stained with sixteen kinds of biotinylated lectin followed by an avidin-biotin-peroxidase complex (ABC). Strong positive reactions in the TM of all 5 kinds of mammals were observed for ConA, PHA-E4, PHA-L4, WGA, ABA, LCA, RCA 60, RCA 120, DSA, and SSA. The TM of the 5 kinds of mammals was weakly positive for Lotus. Rabbit, pig and ox TM were positive for MAM and others were negative. Rabbit, pig and ox TM were weakly positive for PNA and were negative in the other's. Rat TM was weakly positive for SBA and was negative in the other's. The TM of all 5 kinds of mammals was negative for UEA-I and DBA. It could be concluded that species difference exists in lectin binding site in the TM.