Search for Periodic Time Variations of the Solar

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.

Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande.

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}.

Erratum: Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande [Phys. Rev. Lett. 130, 031802 (2023)].

This corrects the article DOI: 10.1103/PhysRevLett.130.031802.

Baseline bio-accumulation concentrations and resulting oxidative stress in Synodontis zambezensis after an acute laboratory exposure to 4,4'-DDT.

The use of 1,1'-(2,2,2-Trichloro-1,1-ethanediyl)bis(4-chlorobenzene) (DDT) as a pesticide for the control of insects vectors responsible for the spread of many life threatening diseases was officially banned in 1972 by the United States Environmental Protection Agency (USEPA). It was banned throughout the world, in most developed countries, because of the toxic effects it causes in wildlife, including birds and fish. However, DDT is still used in approximately 43 African countries, including South Africa, to control the spread of malaria. The lipophilic nature of DDT and therefore its persistence in the environment makes it extremely important for laboratory based studies to be conducted in an effort to evaluate the accumulation potential and possible physiological effects of DDT in aquatic organisms under controlled conditions. The aim of this study was to establish baseline bioaccumulation concentrations within Synodontis zambezensis following an acute exposure to 4,4'-DDT. The three metabolites analysed were 4,4'-DDE, 4,4'-DDD and 4,4'-DDT. None of the 2,4'-isomers were analysed in this study since the acute exposure used a solution of 98.7% pure 4,4'-DDT (Sigma-Aldrich PESTANAL®, Analytical Standard, CAS-No 50-29-3, Batch number SZBE057XV) and not a mixture of 4,4'-DDT and 2,4'-DDT as found in technical grade DDT. Soxhlet extraction of tissue samples and liquid/liquid extraction of water samples followed by analysis through Gas-chromatography mass-spectrophotometry was completed. Mean 4,4'-DDE, 4,4'-DDD and 4,4'-DDT concentrations ranged from 15.34 ng/g to 45.34 ng/g, 28.16 ng/g to 63.25 ng/g and 28.64 ng/g to 96.21 ng/g respectively. All of the accumulated concentrations fell within environmentally relevant concentrations with no input through the food web. The accumulated concentrations of 4,4'-DDT and its three metabolites resulted in oxidative stress responses within the gills and the liver tissue of S. zambezensis. Significant differences (p ≤ .05) were observed between malondialdehyde (MDA) and reduced glutathione (GSH) within the liver and in superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) in the gills.

Search for Boosted Dark Matter Interacting with Electrons in Super-Kamiokande.

A search for boosted dark matter using 161.9 kt yr of Super-Kamiokande IV data is presented. We search for an excess of elastically scattered electrons above the atmospheric neutrino background, with a visible energy between 100 MeV and 1 TeV, pointing back to the Galactic center or the Sun. No such excess is observed. Limits on boosted dark matter event rates in multiple angular cones around the Galactic center and Sun are calculated. Limits are also calculated for a baseline model of boosted dark matter produced from cold dark matter annihilation or decay. This is the first experimental search for boosted dark matter from the Galactic center or the Sun interacting in a terrestrial detector.

Human Health Risk from Consumption of Marine Fish Contaminated with DDT and Its Metabolites in Maputo Bay, Mozambique.

Many countries with incidence of malaria, including those surrounding Maputo Bay, use dichloro-diphenyl-trichloroethane (DDT) to reduce mosquitoes. This study is the first to estimate the human health risk associated with consumption of marine fish from Maputo Bay contaminated with DDTs. The median for ∑DDTs was 3.8 ng/g ww (maximum 280.9 ng/g ww). The overall hazard ratio for samples was 1.5 at the 75th percentile concentration and 28.2 at the 95th percentile. These calculations show increased potential cancer risks due to contamination by DDTs, data which will help policy makers perform a risk-benefit analysis of DDT use in malaria control programs in the region.

Lip b 1 is a novel allergenic protein isolated from the booklouse, Liposcelis bostrychophila.

BACKGROUND: Booklice, belonging to the order Psocoptera, are small household insect pests that are distributed worldwide. Liposcelis bostrychophila, a common home-inhabiting species of booklouse, infests old books, sheets of paper, and stored food. Recent entomological and serological studies demonstrated that L. bostrychophila accounted for the majority of detectable insects in house dust and could be a potent inducer of respiratory allergy. Our recent proteomic analysis identified a potent allergenic protein from L. bostrychophila, designated Lip b 1, and determined its partial amino acid sequences. METHODS: Cloning of cDNAs for Lip b 1 was performed by large-scale transcriptome analysis (RNA-seq) and subsequent reverse transcription polymerase chain reaction. The full-length amino acid sequences deduced from Lip b 1 cDNAs were bioinformatically analyzed. The recombinant proteins of glutathione S-transferase (GST)-fused Lip b 1 were analyzed by Western blot and enzyme-linked immunosorbent assay. RESULTS: Lip b 1 cDNAs encoding two types of 254-amino acid proteins were cloned. The clones shared 87% identity, and the deduced molecular weights and isoelectric points were consistent with those determined in our previous study. The two types of Lip b 1 proteins in the GST-fused form were similarly reactive with sera from allergic patients sensitized with L. bostrychophila. CONCLUSIONS: Lip b 1 is a novel protein possibly causing booklouse allergy.

Systematic review with meta-analysis: performance of dried blood spots for hepatitis C antibodies detection.

OBJECTIVES: Dried blood spots (DBS) specimens can be used for hepatitis C virus (HCV) infection screening in cases where serum specimens are difficult to obtain. However, uncertainties surround the sensitivity and specificity of DBS for HCV antibodies (anti-HCV) serology testing. We aimed to evaluate the accuracy of DBS use to screen for HCV infection. STUDY DESIGN: We carried out a systematic review and meta-analysis. METHODS: Medline and EMBASE databases were searched for articles published between 1989 and November 2016. We included studies comparing DBS to plasma/serum specimens to detect anti-HCV in adults. Two authors extracted data and assessed the quality of the studies using an adapted standards for reporting diagnostic accuracy studies (STARD) and independently checked the data for accuracy. Meta-analysis was computed with the bivariate and the hierarchical summary receiver-operating characteristic models. RESULTS: Twelve studies (3307 specimens) were analyzed, where 11 of them evaluated the anti-HCV using enzyme immunoassays (EIAs), and the remaining one used rapid diagnostic tests. The studies were mostly case-controls (83.3%) and from developed countries (66.7%). The overall pooled sensitivity (95% confidence interval; CI) and specificity (95% CI) of DBS to detect anti-HCV was 98.1% (96.1-99.1%) and 99.7% (98.9-99.9%), respectively. In studies using EIAs, the pooled sensitivity and specificity were 97.3% (94.3-98.8%) and 99.6% (98.5-99.9%), respectively. Considering only studies using EIAs, sensitivity analysis excluding one study carried out in people who inject drugs showed the pooled sensitivity of 97.8% (96.2-98.8%) and specificity of 99.5% (98.5-99.9%). CONCLUSIONS: In testing for anti-HCV by means of EIAs, the efficacy of DBS is found to be similar or slightly lower than that of serum specimens. However, the risk of finding negative and positive results that are both false when using DBS remains present. Therefore, further work including optimal storage and processing methodologies are recommended. This is to help establish consensus guidelines for use of DBS specimens for anti-HCV screening.

Pregnancies with factor V deficiency: a case report and review of the literature.

CASE REPORT: A 30-year-old Japanese nulliparous woman visited for pregnancy at 33 weeks with a massive ovarian tumor located in the pouch of Douglas. By preoperative screening, her prothrombin time (PT) and activated partial thromboplastin time (APTT) were prolonged, and her FV activity was significantly decreased to 4.8%. After prophylactic FFP 20 ml/kg was administered and her FV factor was 19.3%, cesarean delivery was performed, and her perioperative course was uneventful. One year later, she underwent a dilatation and evacuation because of a missed abortion, although prophylactic FFP was not administered. During a third pregnancy, after prophylactic FFP 20 ml/kg was administered and FV activity increased to 21.1%, elective cesarean delivery was performed, and her postoperative course was uneventful. CONCLUSION: For surgical therapy or delivery, the goal of therapy is to maintain FV activity above 20%. It is particularly useful to administer prophylactic FFP.

Fast Heating of Imploded Core with Counterbeam Configuration.

A tailored-pulse-imploded core with a diameter of 70 µm is flashed by counterirradiating 110 fs, 7 TW laser pulses. Photon emission (>40 eV) from the core exceeds the emission from the imploded core by 6 times, even though the heating pulse energies are only one seventh of the implosion energy. The coupling efficiency from the heating laser to the core using counterirradiation is 14% from the enhancement of photon emission. Neutrons are also produced by counterpropagating fast deuterons accelerated by the photon pressure of the heating pulses. A collisional two-dimensional particle-in-cell simulation reveals that the collisionless two counterpropagating fast-electron currents induce mega-Gauss magnetic filaments in the center of the core due to the Weibel instability. The counterpropagating fast-electron currents are absolutely unstable and independent of the core density and resistivity. Fast electrons with energy below a few MeV are trapped by these filaments in the core region, inducing an additional coupling. This might lead to the observed bright photon emissions.

Foams stabilized with solid particles carrying stimuli-responsive polymer hairs.

Submicrometer-sized polystyrene (PS) particles carrying stimuli-responsive poly[2-(diethylamino)ethyl methacrylate] (PDEA) hairs with degrees of polymerization of 30, 60 and 90 were synthesized by dispersion polymerization and used as a particulate foam stabilizer. The effects of the composition of these PDEA-PS particles and foam formation conditions on foamability, foam stability and foam microstructures were extensively investigated. The hairy particles were found to work as an effective stabilizer of aqueous foams in basic media, in which the PDEA hairs are not protonated and thus the particle surfaces exhibit suitable wettability at the air-water interface. In contrast, little to no foam or unstable foams were formed in acidic aqueous media, in which the hairs are protonated and are therefore water soluble. Particles carrying longer hairs resulted in greater foamability and more highly stabilized foams that were capable of persisting for more than one month. Foams were found to form in a narrower pH range when using PS particles with longer hairs, due to both entropic and image charge effects. Data obtained from the touch mixer mixing method showed that both foamability and foam stability increased with increases in the concentration of polymer particles up to 10 wt%, because higher concentrations allowed greater air-water interfacial areas to be stabilized. Conversely, only minimal foam was obtained at and above 15 wt% because of the high viscosity of the resulting aqueous particle dispersion. Trials using the homogenizer mixing method showed that foam with a cream-like texture could be formed even at 40 wt% particle concentration as a result of the improved mixing efficiency. Defoamation could be induced by exposing the foams to HCl vapor. Exposure to acidic vapor led to in situ protonation of the 2-(diethylamino)ethyl methacrylate residues, rendering the PDEA hairs hydrophilic and water soluble, and desorption of the PDEA-PS particles from the air-water interface.

Characterization of equine cytochrome P450: role of CYP3A in the metabolism of diazepam.

Research on drug metabolism and pharmacokinetics in large animal species including the horse is scarce because of the challenges in conducting in vivo studies. The metabolic reactions catalyzed by cytochrome P450s (CYPs) are central to drug pharmacokinetics. This study elucidated the characteristics of equine CYPs using diazepam (DZP) as a model compound as this drug is widely used as an anesthetic and sedative in horses, and is principally metabolized by CYPs. Diazepam metabolic activities were measured in vitro using horse and rat liver microsomes to clarify the species differences in enzyme kinetic parameters of each metabolite (temazepam [TMZ], nordiazepam [NDZ], p-hydroxydiazepam [p-OH-DZP], and oxazepam [OXZ]). In both species microsomes, TMZ was the major metabolite, but the formation rate of p-OH-DZP was significantly less in the horse. Inhibition assays with a CYP-specific inhibitors and antibody suggested that CYP3A was the main enzyme responsible for DZP metabolism in horse. Four recombinant equine CYP3A isoforms expressed in Cos-7 cells showed that CYP3A96, CYP3A94, and CYP3A89 were important for TMZ formation, whereas CYP3A97 exhibited more limited activity. Phylogenetic analysis suggested diversification of CYP3As in each mammalian order. Further study is needed to elucidate functional characteristics of each equine CYP3A isoform for effective use of diazepam in horses.

Behaviour in a standardized assay, but not metabolic or growth rate, predicts behavioural variation in an adult aquatic top predator Esox lucius in the wild.

This study tested for links among behaviour, state and life-history variables as predicted by the pace-of-life hypothesis in adult pike Esox lucius. First, a standardized open-field behavioural assay was developed to assess individual behaviour of wild-captured adult E. lucius. Behaviour within the standardized assay predicted swimming behaviour in the lake, providing an ecological validation of the assay. There was no relationship between standardized behaviour and any of the life-history and state variables, including metabolism, body condition, juvenile growth rate and adult growth rate in contrast to predictions from the pace-of-life hypothesis. This study demonstrates that it is possible to assess ecologically relevant behavioural variation in a large-bodied top predator using a standard open-field assay, but it is noteworthy that this standardized behaviour is not systematically related to standard metabolism or growth.

Search for Nucleon and Dinucleon Decays with an Invisible Particle and a Charged Lepton in the Final State at the Super-Kamiokande Experiment.

Search results for nucleon decays p→e^{+}X, p→µ^{+}X, n→νγ (where X is an invisible, massless particle) as well as dinucleon decays np→e^{+}ν, np→µ^{+}ν, and np→τ^{+}ν in the Super-Kamiokande experiment are presented. Using single-ring data from an exposure of 273.4 kton·yr, a search for these decays yields a result consistent with no signal. Accordingly, lower limits on the partial lifetimes of τ_{p→e^{+}X}>7.9×10^{32} yr, τ_{p→µ^{+}X}>4.1×10^{32} yr, τ_{n→νγ}>5.5×10^{32} yr, τ_{np→e^{+}ν}>2.6×10^{32} yr, τ_{np→µ^{+}ν}>2.2×10^{32} yr, and τ_{np→τ^{+}ν}>2.9×10^{31} yr at a 90% confidence level are obtained. Some of these searches are novel.

Search for neutrinos from annihilation of captured low-mass dark matter particles in the sun by super-kamiokande.

Super-Kamiokande (SK) can search for weakly interacting massive particles (WIMPs) by detecting neutrinos produced from WIMP annihilations occurring inside the Sun. In this analysis, we include neutrino events with interaction vertices in the detector in addition to upward-going muons produced in the surrounding rock. Compared to the previous result, which used the upward-going muons only, the signal acceptances for light (few-GeV/c^{2}-200-GeV/c^{2}) WIMPs are significantly increased. We fit 3903 days of SK data to search for the contribution of neutrinos from WIMP annihilation in the Sun. We found no significant excess over expected atmospheric-neutrino background and the result is interpreted in terms of upper limits on WIMP-nucleon elastic scattering cross sections under different assumptions about the annihilation channel. We set the current best limits on the spin-dependent WIMP-proton cross section for WIMP masses below 200 GeV/c^{2} (at 10 GeV/c^{2}, 1.49×10^{-39} cm^{2} for χχ→bb[over ¯] and 1.31×10^{-40} cm^{2} for χχ→τ^{+}τ^{-} annihilation channels), also ruling out some fraction of WIMP candidates with spin-independent coupling in the few-GeV/c^{2} mass range.

Can maternally inherited endosymbionts adapt to a novel host? Direct costs of Spiroplasma infection, but not vertical transmission efficiency, evolve rapidly after horizontal transfer into D. melanogaster.

Maternally inherited symbionts are common in arthropods and many have important roles in host adaptation. The observation that specific symbiont lineages infect distantly related host species implies new interactions are commonly established by lateral transfer events. However, studies have shown that symbionts often perform poorly in novel hosts. We hypothesized selection on the symbiont may be sufficiently rapid that poor performance in a novel host environment is rapidly ameliorated, permitting symbiont maintenance. Here, we test this prediction for a Spiroplasma strain transinfected into the novel host Drosophila melanogaster. In the generations immediately following transinfection, the symbiont had low transmission efficiency to offspring and imposed severe fitness costs on its host. We observed that effects on host fitness evolved rapidly, being undetectable after 17 generations in the novel host, whereas vertical transmission efficiency was poorly responsive over this period. Our results suggest that long-term symbiosis may more readily be established in cases where symbionts perform poorly in just one aspect of symbiosis.

Aqueous foams stabilized by temperature-sensitive hairy polymer particles.

Submicrometer-sized polystyrene (PS) particles carrying poly[2-(diethylamino)ethyl methacrylate] (PDEA) hairs (PDEA-PS particles) were synthesized by free radical dispersion polymerization. The hydrophilicity-hydrophobicity balance of the PDEA could be tuned by varying the temperature at near neutral pH (a lower critical solution temperature of PDEA at pH 6.86, 41 °C) and therefore these sterically-stabilized particles acted as temperature-sensitive stabilizers for aqueous foams. At 25 °C, where the PDEA hairs were hydrated and PDEA-PS particles were colloidally stable in aqueous media, foams were formed which coalesced with time and the size of the bubble increased. At 40 and 45 °C, where the PDEA hairs were partially non-hydrated and PDEA-PS particles were close to flocculation or weakly flocculated, foams were formed and bubble coalescence and size increase speeds were slower than those observed at 25 °C. At and above 50 °C, where the PDEA hairs were non-hydrated and PDEA-PS particles were heavily flocculated in aqueous media, the more stable cream-like foams whose volume was almost the same for 1 week were formed. Scanning electron microscopy studies indicated that the particles mainly adsorbed at the air-water interface as monolayers at 25 °C and as multilayers at and above 40 °C. The foam stability and structure could be controlled by changing the temperature.

Partial cloning of CYP2C23a genes and hepatic protein expression in eight representative avian species.

Large interspecies differences in avian xenobiotic metabolism have been revealed by microsome-based studies, but specific enzyme isoforms in different bird species have not yet been compared. We have previously shown that CYP2C23 genes are the most induced CYP isoforms in chicken liver. In this study, we collected partial CYP2C23a gene sequences from eight avian species (ostrich, blue-eared pheasant, snowy owl, great-horned owl, Chilean flamingo, peregrin falcon, Humboldt penguin, and black-crowned night heron) selected to cover the whole avian lineage: Paleognathae, Galloanserae, and Neoaves. Genetic analysis showed that CYP2C23 genes of Galloanserae species (chicken and blue-eared pheasant) had unique characteristics. We found some duplicated genes (CYP2C23a and CYP2C23b) and two missing amino acid residues in Galloanserae compared to the other two lineages. The genes have lower homology than in other avian lineages, which suggests Galloanserae-specific rapid evolutionary changes. These genetic features suggested that the Galloanserae are not the most representative avian species, considering that the Neoaves comprise more than 95% of birds. Moreover, we succeeded in synthesizing an antipeptide polyclonal antibody against the region of CYP2C23 protein conserved in avians. However, comparative quantitation of CYP2C23 proteins in livers from six species showed that expression levels of these proteins differed no more than fourfold. Further study is needed to clarify the function of avian CYP2C23 proteins.

Search for trilepton nucleon decay via p→e+νν and p→µ+νν in the Super-Kamiokande experiment.

The trilepton nucleon decay modes p→e+νν and p→µ+νν violate |Δ(B-L)| by two units. Using data from a 273.4 kt yr exposure of Super-Kamiokande a search for these decays yields a fit consistent with no signal. Accordingly, lower limits on the partial lifetimes of τp→e+νν>1.7×10(32) years and τp→µ+νν>2.2×10(32) years at a 90% confidence level are obtained. These limits can constrain Grand Unified Theories which allow for such processes.

Search for nucleon decay via n→ν[over ¯]π0 and p→ν[over ¯]π+ in Super-Kamiokande.

We present the results of searches for nucleon decay via n→ν[over ¯]π0 and p→ν[over ¯]π+ using data from a combined 172.8 kt·yr exposure of Super-Kamiokande-I,-II, and-III. We set lower limits on the partial lifetime for each of these modes: τn→ν[over ¯]π0>1.1×10(33) years and τp→ν[over ¯]π+>3.9×10(32) years at a 90% confidence level.