Search

We report a search for time variations of the solar ^{8}B neutrino flux using 5804 live days of Super-Kamiokande data collected between May 31, 1996, and May 30, 2018. Super-Kamiokande measured the precise time of each solar neutrino interaction over 22 calendar years to search for solar neutrino flux modulations with unprecedented precision. Periodic modulations are searched for in a dataset comprising five-day interval solar neutrino flux measurements with a maximum likelihood method. We also applied the Lomb-Scargle method to this dataset to compare it with previous reports. The only significant modulation found is due to the elliptic orbit of the Earth around the Sun. The observed modulation is consistent with astronomical data: we measured an eccentricity of (1.53±0.35)%, and a perihelion shift of (-1.5±13.5) days.

We report a search for cosmic-ray boosted dark matter with protons using the 0.37  megaton×years data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross section between 10^{-33}cm^{2} and 10^{-27}cm^{2} for dark matter mass from 1  MeV/c^{2} to 300  MeV/c^{2}.

Herein, we developed selective coupling and polymerization systems of folded polymer micelles via physical interaction in water. The polymer micelles serve as nanodomains to provide double core micelles, alternating necklace micelles, and micelle-connected hydrogels. For this, cation- or anion-tail unimer micelles and amine- or carboxy-tail unimer micelles were designed; the unimer micelles consist of folded amphiphilic random copolymers carrying hydrophilic poly(ethylene glycol) and hydrophobic or hydrogen-bonding pendants. Mixing a cation-tail micelle and an anion-tail micelle, and even the combination of a double cation-tail micelle and a double anion-tail micelle, selectively provided double-core micelles in water without forming large aggregates. Double core micelles afforded structural transformation into linear or cyclic polymers and dynamic exchange of the micelle domains. In contrast, mixing amine-tail micelles and carboxy-tail micelles gave an alternating necklace micelle or a hydrogel. The controlled connection of polymer micelles was achieved by designing suitable physical interaction. This technique opened new ways to create various nanodomain self-assemblies with controlled higher-order structure.

Increased susceptibility to Rhizopus oryzae in diabetes was investigated using mice in which diabetic ketoacidosis was experimentally induced. All of the diabetic mice which had developed ketoacidosis died within four days after inoculation of R. oryzae and their serum UIBCs (Unbound iron binding capacity) were significantly lower than those of the normal control mice. This study suggested that the decreased serum UIBC produced by diabetic ketoacidosis enhances the growth of R. oryzae in vivo.

In an attempt to study the influence of iron overload on deep mycotic infection, experimental candidiasis was induced in mice. One group received intravenous injections of colloidal iron (60 mg/kg weight) for three consecutive days before intravenous inoculation of Candida albicans spores (1 X 10(7). The other received the same number of Candida spores without iron overload. The animals in both groups were observed for 28 days. The Candida lesions, regardless of iron administration, were located mainly in the kidney. There was a marked difference in mortality between the two groups, i.e., 40% in the group without iron administration and 80% in the group with it. The higher mortality rate in the latter group may be explained by following reasons: increased serum iron and iron saturation (iron is essential to the growth of Candida), decreased phagocytic activity against intravenously inoculated Candida because of the saturation of the phagocytic cells by the preceding colloidal iron administration and enhanced proliferation of Candida, which tends to involve the kidney, exposed to abundant iron in the kidney due to increased excretion. The current experiment showed that excessive iron clearly promoted the proliferation of intravenously inoculated Candida in vivo.

We are reporting a case of a rare renal actinomycosis in a 12-year-old mentally-retarded girl. Proteinuria and hemopyuria were pointed out one year before the operation by an annual medical check-up and IVP subsequently performed showed foreign bodies at the upper pole of the right kidney. The patient continued to have pyuria and right nephrectomy was performed. There was a fistula between the duodenum and the upper portion of the right kidney. Foreign bodies (two bobby pins) were found in the kidney. Subsequent pathologic examination of the resected kidney revealed an actinomycotic lesion.

In the study of disseminated fungal infection, in consecutive autopsy cases between 1974 and 1982, we have found this infection in 20 cases (2.55% in all autopsy cases and 16.8% of deep-seated fungal infection). Candidiasis was present in 11 cases, aspergillosis in 8 cases, and mucormycosis and cryptococcosis in 1 case each. One case showed the disseminated infection by both Candida and Aspergillus. All of the 20 cases had underlying disorders. Hematologic disorders were most frequent and were present in 15 cases. In contrast to the small yellow disseminated foci of candidiasis, the lesion by Aspergillus and Mucor were relatively larger, hemorrhagic, and necrotic. Cryptococcal lesion showed a small gelatinous appearance. All of the fungal lesion were devoid of significant inflammatory reaction. Lymphocytopenia (less than 500/mm3) was present in 13 cases out of 16 cases (not examined in the remaining 4 cases). Eight cases had long-standing indwelling intravenous catheters, including two cases in which the catheters apparently played an important role in the development of disseminated candidiasis. Ante-mortem diagnosis was established or suspected in only seven cases. Possible means of the prevention of fungal infection is also discussed.

The defense mechanisms against Candida albicans infection were studied by using a mouse thigh lesion model in congenitally athymic nude (nu/nu) mice and their normal littermates (nu/+). Nu/nu mice were more resistant to C. albicans infection than nu/+ mice judging from the course of the thigh lesion, the results of CFUs (colony-forming units) of C. albicans in the lesion, and histopathological observations. Histopathological and serological studies revealed that granulocytic cellular infiltration was predominant, and there were few indications of development of cell-mediated immunity to protect Candida infection in Candida-infected nu/nu and nu/+ mice. These results confirmed that lower susceptibility of nu/nu mice to C. albicans infection as compared to nu/+ mice was due to accelerated non-specific defense mechanisms in nu/nu mice, and that cell-mediated or humoral immunity played a minor role in the defense against Candida infection in this experimental model. Furthermore, treatment with high titer of rabbit anti-C. albicans serum was effective to control the number of Candida cells in thigh lesions of BALB/c mice. Above experimental results seem to clearly indicate the great variability of defense manifestation according to the experimental model exployed.

The histopathological examination was performed in search of cerebral mycosis in autopsy cases at our department during the 6 years from 1976 to 1981. The cerebral mycoses were histopathologically verified in seven cases, although brain tissue was examined in only 46% of 528 autopsy cases. All cases of cerebral mycosis showed underlying diseases which were hematologic diseases (5 cases), SLE (1 case), and myocardial infarction with indwelling deep venous lines (1 case). Among these cerebral mycosis, one had double fungal infections with aspergillus and candida, while others were as follows; aspergillosis (2 cases), mucormycosis (2 cases), candidiasis (1 case) and cryptococcosis (1 case). Six cases were not diagnosed antemortem with exception of a case of cryptococcosis. Systemic fungal infections were seen in six cases, however, a case of mucormycosis was without systemic infection. Each cerebral mycosis showed its own characteristic histopathologic findings, namely, hemorrhagic and necrotic lesions in aspergillosis and mucormycosis, scattered minute abscesses or granulomatous lesions in candidiasis, and gelatinous lesions in leptomeninges in cryptococcosis. Severe lymphocytopenia (less than 500/mm3) was always present in all except a case of rhinocerebral mucormycosis. It is emphasized that cerebral mycosis should be always considered when neurological symptoms were clinically observed in patients who had severe underlying diseases and/or deep venous lines with severe lymphocytopenia.

Peptide mycotoxins "leucinostatins" were obtained from the culture strains of Paecilomyces lilacinus, which were isolated both from soil and a case of human oculomycosis. Comparative studies of the symptoms of experimental keratomycosis caused both by the inoculation of P. lilacinus and by direct administration of leucinostatins into the infection model in rabbit suggested the possible role of leucinostatins in the inflammatory response of invaded tissues. Leucinostatin was formerly reported as a single entity. However, in the course of the structural studies, leucinostatin was found to be a complex of two closely related components, and the structures of the both mycotoxins were determined. Both of the mycotoxins possessed high toxicity to experimental animals. The intraperitoneal and oral LD50 values in mice were 1.8 and 5.4 to 6.3 mg/kg by a single administration. Toxicological studies showed that leucinostatins have some potent effects on liver cells after oral administration. It was also found that leucinostatins exhibit strong uncoupling activity on rat liver mitochondrial system.

In the early stage of myocardial infarction, the mortality rate is very high and its diagnosis is difficult not only clinically but also pathologically. Hematoxylin basic fuchsin picric acid (HBFP) staining method has been controversial on reliability for the morphologic diagnosis of early stages of myocardial ischemia. We applied HBFP staining method improved hematoxylin staining and differentiating solution to 42 human autopsy hearts. In eight cases with diagnosed acute myocardial infarction clinically and/or pathologically and 4 cases that suffered from post-infarction angina and died suddenly at home or outdoors, HBFP stain showed positive. Other cases, including non-ischemic heart disease and sudden death due to non-cardiac disease and ventricular arrhythmia, were HBFP staining negative. In conclusion, improved HBFP staining method is useful in identifying early myocardial ischemia and extent of early infarcts, and explaining for sudden death due to re-attack of myocardial infarction.