An AsCas12f-based compact genome-editing tool derived by deep mutational scanning and structural analysis

SpCas9 and AsCas12a are widely utilized as genome-editing tools in human cells. However, their relatively large size poses a limitation for delivery by cargo-size-limited adeno-associated virus (AAV) vectors. The type V-F Cas12f from Acidibacillus sulfuroxidans is exceptionally compact (422 amino acids) and has been harnessed as a compact genome-editing tool. Here, we developed an approach, combining deep mutational scanning and structure-informed design, to successfully generate two AsCas12f activity-enhanced (enAsCas12f) variants. Remarkably, the enAsCas12f variants exhibited genome-editing activities in human cells comparable with those of SpCas9 and AsCas12a. The cryoelectron microscopy (cryo-EM) structures revealed that the mutations stabilize the dimer formation and reinforce interactions with nucleic acids to enhance their DNA cleavage activities. Moreover, enAsCas12f packaged with partner genes in an all-in-one AAV vector exhibited efficient knock-in/knock-out activities and transcriptional activation in mice. Taken together, enAsCas12f variants could offer a minimal genome-editing platform for in vivo gene therapy.

Early experience with coronary debulking devices in a newcomer facility after introducing revised facility criteria in Japan

Coronary debulking devices are essential in obtaining optimal results in percutaneous coronary intervention (PCI) for severely calcified lesions. However, since the introduction of these devices in Japan, the presence of full-time cardiovascular surgeons in their own facilities has been an essential condition (on-site surgical back-up) as the facility criteria for their use. The criteria were revised in April 2020, making their implementation possible at our hospital. Between May 2020 and January 2022, we administered PCIs using rotational atherectomy (RA) for 33 lesions in 28 patients and orbital atherectomy system (OAS) for 36 lesions in 27 patients. The most preferred strategy in our hospital is OAS via the distal radial approach using a 6Fr Glide sheath or RA via the femoral approach using a 7Fr sheath. The percentages of usable imaging modality as an initial device without lesion modification were 57.1 and 66.7% in the RA and OAS groups, respectively. In the RA procedure, 1.5- and 2.0-mm Rota burrs were more frequently adopted for the initial and second sessions, respectively. In the OAS procedure, the debulking was always initiated at a low speed. Nineteen of the 27 patients underwent additional high-speed debulking. Pre-procedural quantitative coronary angiographic analysis revealed that the minimal lumen diameter was significantly smaller in the RA than in the OAS group. Debulking procedures were successful in all patients excluding two instances of procedure-related complications in the RA group, one of which was coronary perforation safely treated via covered stent deployment without any resulting hemodynamic instability. Our early experience with coronary debulking devices with off-site surgical back-up clearly reveals the safety and feasibility of this procedure in a newcomer facility.

Percutaneous debulking strategy for severe nodular calcification in common femoral artery

BACKGROUND

Despite marked progress in endovascular treatment (EVT) techniques and devices, calcified lesions remain one of the toughest obstacles to EVT success. Moreover, because the common femoral artery (CFA) is known as a "non-stenting zone," endovascular strategies for this area are controversial.

CASE PRESENTATION

Here we describe the technical tips for a novel, less invasive, and effective debulking strategy for severe nodular calcification using an endovascular maneuver. This technique was demonstrated in a 73-year-old man with severe calcified stenosis of the CFA. To complete a stent-less strategy for CFA, we conducted aggressive debulking of the nodular calcification, established a bidirectional approach from the radial artery and the superficial femoral artery (SFA), and inserted a balloon-guiding catheter in the SFA. Under distal protection provided by this catheter, we crushed the nodular calcification 43 times using myocardial biopsy forceps. After achieving a volume reduction of nodular calcification through this maneuver, we completed the procedure by inflating a 6-mm drug-coated balloon catheter. Final angiography demonstrated a reduced filling defect of the contrast medium in the CFA and favorable blood flow as far as the ankle. The puncture site on the SFA was closed with a vascular suture assisted by balloon inflation inside the vessel, which allowed the patient to be ambulatory immediately after the procedure without requiring bed rest.

CONCLUSIONS

Severely calcified lesions in the CFA are usually difficult to treat using an endovascular strategy, but our novel and less invasive method may become a promising technique for managing these lesions.

Endovascular Treatment for Vascular Access Venous Hypertension with Complicated Venous Drainage Routes in a Hemodialysis Patient: A Case Report

Patient: Female, 68-year-old

Final Diagnosis: Vascular access venous hypertension

Symptoms: Difficulties during hemodialysis

Medication: —

Clinical Procedure: —

Specialty: Cardiology • Nephrology • Radiology

A Novel Guidewire Pull-Through Technique in Endovascular Treatment for Severely Calcified Infrapopliteal Occlusion

BACKGROUND In practical settings of endovascular treatment (EVT) for below-the-knee arteries, we often encounter cases of severe calcification. To overcome problems regarding device uncrossing due to severe calcifications, a bidirectional approach and subsequent guidewire externalization is one of critical methods. CASE REPORT A 74-year-old female with refractory skin ulcers on the lower frontal thigh and necrotic toes on the left side showed occlusion in both the anterior tibial artery (ATA) and tibio-peroneal trunk. Both occluded vessels were accompanied with dense calcification. In the process of EVT targeting the occluded ATA, the retrograde guidewire successfully passed the occlusion and was advanced into the antegrade guide sheath. Next, we attempted guidewire externalization, but severe calcification of the ATA hampered the procedure. Therefore, we introduced a guide extension catheter and a balloon catheter in an antegrade fashion to establish a system of trapping the retrograde guidewire between these devices. Then, we pulled the system back outside the guide sheath, which completed guidewire externalization. We performed prolonged balloon dilatation and finally achieved favorable revascularization of the ATA. CONCLUSIONS Our novel method led to successful retrograde guidewire externalization, overcoming severely calcified lesions. It is generally essential for clinicians to increase their expertise regarding EVT procedures to attain better outcomes.

A noteworthy clue for diagnosing non-ST-elevation myocardial infarction by computed tomography without ECG synchronization: a case report

Background

Although timely coronary intervention can result in markedly improved clinical outcomes of patients with acute coronary syndrome (ACS), non-ST-elevation (NSTE)-ACS is sometimes difficult to accurately diagnose.

Case presentation

A 52-year-old woman complained of acute chest pain with sudden onset. Both electrocardiography (ECG) and echocardiography showed normal results, and we urgently needed to make a differential diagnosis among critical illnesses such as acute coronary syndrome and nonischemic cardiovascular life-threatening diseases. Contrast-enhanced computed tomography (CT) without ECG synchronization showed evidence of neither aortic dissection nor pulmonary embolism, but regionally reduced contrast enhancement in the posterior myocardium, which were suggestive of myocardial ischemia. Emergency coronary angiography demonstrated severe stenosis of the left circumflex artery, and we achieved favorable revascularization with drug-eluting stent deployment.

Conclusions

We diagnosed a patient with NSTE-ACS in whom contrast-enhanced CT without ECG synchronization was effective for visualization of reduced myocardial perfusion, suggesting ischemic heart disease.

Successful limb salvage by endovascular treatment for critical limb ischemia subsequent to acute limb ischemia

Recently, there have been increasing opportunities to treat patients with peripheral arterial disease. Of those patients, both pathological conditions, such as acute limb ischemia (ALI) and chronic critical limb ischemia (CLI), are closely associated with high risks of major amputation, disability and death. We encountered a very rare case of CLI subsequent to ALI. An 83-year-old male showed the sudden onset of ALI, probably due to thromboembolism from an abdominal aortic aneurysm during an operation for gastric cancer. The patient was referred to another hospital for Fogarty thrombectomy. About 1 month after ALI onset, necrosis of the left first toe gradually progressed. On angiography of the left lower limb, we noted occlusions of both anterior and posterior tibial arteries. Then, we successfully conducted balloon angioplasty for the below-the-knee arteries. Thereby, favorable blood flow was achieved, which led to successful wound healing without amputations.

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.

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.

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.

Search for bosonic superweakly interacting massive dark matter particles with the XMASS-I detector

Bosonic superweakly interacting massive particles (super-WIMPs) are a candidate for warm dark matter. With the absorption of such a boson by a xenon atom, these dark matter candidates would deposit an energy equivalent to their rest mass in the detector. This is the first direct detection experiment exploring the vector super-WIMPs in the mass range between 40 and 120 keV. With the use of 165.9 day of data, no significant excess above background was observed in the fiducial mass of 41 kg. The present limit for the vector super-WIMPs excludes the possibility that such particles constitute all of dark matter. The absence of a signal also provides the most stringent direct constraint on the coupling constant of pseudoscalar super-WIMPs to electrons. The unprecedented sensitivity was achieved exploiting the low background at a level 10(-4)  kg-1 keVee-1 day-1 in the detector.

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 dinucleon decay into kaons in Super-Kamiokande

A search for the dinucleon decay pp → K+ K+ has been performed using 91.6  kton·yr data from Super-Kamiokande-I. This decay provides a sensitive probe of the R-parity-violating parameter λ112''. A boosted decision tree analysis found no signal candidates in the data. The expected background was 0.28±0.19 atmospheric neutrino induced events and the estimated signal detection efficiency was 12.6%±3.2%. A lower limit of 1.7×10(32)  years has been placed on the partial lifetime of the decay O16 → C14K+ K+ at 90% C.L. A corresponding upper limit of 7.8×10(-9) has been placed on the parameter λ112''.

First indication of terrestrial matter effects on solar neutrino oscillation

We report an indication that the elastic scattering rate of solar B8 neutrinos with electrons in the Super-Kamiokande detector is larger when the neutrinos pass through Earth during nighttime. We determine the day-night asymmetry, defined as the difference of the average day rate and average night rate divided by the average of those two rates, to be [-3.2 ± 1.1(stat) ± 0.5(syst)]%, which deviates from zero by 2.7 σ. Since the elastic scattering process is mostly sensitive to electron-flavored solar neutrinos, a nonzero day-night asymmetry implies that the flavor oscillations of solar neutrinos are affected by the presence of matter within the neutrinos' flight path. Super-Kamiokande's day-night asymmetry is consistent with neutrino oscillations for 4 × 10(-5)  eV(2) ≤ Δm 2(21) ≤ 7 × 10(-5) eV(2) and large mixing values of θ12, at the 68% C.L.

Evidence for the appearance of atmospheric tau neutrinos in super-Kamiokande

Super-Kamiokande atmospheric neutrino data were fit with an unbinned maximum likelihood method to search for the appearance of tau leptons resulting from the interactions of oscillation-generated tau neutrinos in the detector. Relative to the expectation of unity, the tau normalization is found to be 1.42 ± 0.35(stat)(-0.12)(+0.14)(syst) excluding the no-tau-appearance hypothesis, for which the normalization would be zero, at the 3.8σ level. We estimate that 180.1 ± 44.3(stat)(-15.2)(+17.8) (syst) tau leptons were produced in the 22.5 kton fiducial volume of the detector by tau neutrinos during the 2806 day running period. In future analyses, this large sample of selected tau events will allow the study of charged current tau neutrino interaction physics with oscillation produced tau neutrinos.

Search for differences in oscillation parameters for atmospheric neutrinos and antineutrinos at Super-Kamiokande

We present a search for differences in the oscillations of antineutrinos and neutrinos in the Super-Kamiokande-I, -II, and -III atmospheric neutrino sample. Under a two-flavor disappearance model with separate mixing parameters between neutrinos and antineutrinos, we find no evidence for a difference in oscillation parameters. Best-fit antineutrino mixing is found to be at (Δm2,sin2 2θ)=(2.0×10(-3)  eV2, 1.0) and is consistent with the overall Super-K measurement.

Mitigation of occult lung injury by pneumonectomy via minithoracotomy in mice

BACKGROUND

The systemic and pulmonary inflammatory response associated with pneumonectomy performed via minithoracotomy versus that after open posterolateral thoracotomy is uncertain.

METHODS

Groups consisting of 7 randomly assigned mice underwent a) minithoracotomy (with 5-mm long incisions and sparing of the muscles) alone, b) posterolateral thoracotomy (with 20-mm long incisions) alone, c) pneumonectomy via minithoracotomy, or d) pneumonectomy via posterolateral thoracotomy. The animals' daily food intake, body weight changes and spontaneous activity were monitored for 10 days, and lung water accumulation and vascular hyperpermeability in the remaining right lung were measured at 24 h after surgery. Concentrations of high mobility group box 1 protein (HMGB1), a mediator of inflammation and shock, were measured in the bronchoalveolar lavage fluid.

RESULTS

Compared with posterolateral thoracotomy, pneumonectomy via minithoracotomy was associated with significantly less weight loss (p < 0.05), despite a similar daily food intake among the groups. Spontaneous activity after pneumonectomy via minithoracotomy returned earlier than after posterolateral thoracotomy. Pulmonary vascular hyperpermeability and water retention in the residual lung were significantly less prominent after pneumonectomy performed via minithoracotomy than after pneumonectomy via posterolateral thoracotomy (both comparisons p < 0.05). HMGB1 concentrations in the bronchoalveolar lavage fluid collected from the residual lung were significantly lower (p < 0.05) after minithoracotomy than after posterolateral thoracotomy.

CONCLUSIONS

Based on postoperative weight loss, spontaneous activity, and the degree of pulmonary capillary injury in the residual lung, pneumonectomy via minithoracotomy was less invasive than posterolateral thoracotomy. The lower increase in HMGB1 associated with minithoracotomy might result in lower pulmonary vascular hyperpermeability and reflect less surgical invasiveness.

Search for proton decay via p-->e+pi0 and p-->micro+pi0 in a large water Cherenkov detector

We have searched for proton decays via p-->e;{+}pi;{0} and p-->micro;{+}pi;{0} using data from a 91.7 kt.yr exposure of Super-Kamiokande-I and a 49.2 kt.yr exposure of Super-Kamiokande-II. No candidate events were observed with expected backgrounds induced by atmospheric neutrinos of 0.3 events for each decay mode. From these results, we set lower limits on the partial lifetime of 8.2 x 10;{33} and 6.6 x 10;{33} years at 90% confidence level for p-->e;{+}pi;{0} and p-->micro;{+}pi;{0} modes, respectively.

Accuracy of an interferon-gamma release assay to detect active pulmonary and extra-pulmonary tuberculosis

OBJECTIVE

To examine the performance of an interferon-gamma (IFN-gamma) release assay (QuantiFERON-TB 2G assay [QFT-G]) to detect Mycobacterium tuberculosis infection in a Japanese general hospital, for the diagnosis of active pulmonary tuberculosis (PTB) and extra-pulmonary tuberculosis (EPTB).

DESIGN

We prospectively examined the performance of QFT-G in 194 patients suspected of active TB. Diagnosis was confirmed by 1) positive M. tuberculosis cultures, or 2) clinical manifestations or laboratory or pathological findings consistent with active TB and response to specific therapy.

RESULTS

Three patients with indeterminate QFT-G results were excluded. Among the remaining 191 patients, 77 had active TB. When the cut-off concentration of IFN-gamma was set at 0.35 IU/ml, as recommended by the manufacturer, the assay was positive in 69 patients and negative in 122. The sensitivity of the assay was 76.6% in all patients, 74.5% in the 47 patients with PTB and 80.0% in the 30 patients with EPTB. The overall specificity of the assay was 91.2%.

CONCLUSION

Although the specificity of the QFT-G to detect active TB was high and its sensitivity low, it was as accurate for the detection of active EPTB as for PTB when the 0.35 IU/ml INF-gamma cut-off concentration was used.

Neutrophil elastase inhibitor improves postoperative clinical courses after thoracic esophagectomy

Sivelestat sodium hydrate is a selective inhibitor of neutrophil elastase (NE), and is effective in acute lung injury associated with systemic inflammatory response syndrome (SIRS). The effect of Sivelestat for postoperative clinical courses after transthoracic esophagectomy was investigated. Consecutive patients with carcinoma of the thoracic esophagus who underwent transthoracic esophagectomy between 2003 and 2004 were assigned to the Sivelestat-treated group (n = 18), and those between 1998 and 2003 were assigned to the control group (n = 25). The morbidity rate, duration of postoperative SIRS, mechanical ventilation, and intensive care unit (ICU) stay, and the sum of the sequential organ failure assessment scores at all time points after the operation were compared. Serum NE activities and serum concentrations of TNF-alpha, IL-1beta, IL-6, and high mobility group box chromosomal protein 1 (HMGB1) were measured. Postoperative complications developed in three patients in the control group, and one in the Sivelestat-treated group. The durations of SIRS, mechanical ventilation, and ICU stay were significantly shorter in the Sivelestat-treated group. Even in patients without complications, the durations of mechanical ventilation, and ICU stay were also significantly shorter, and the arterial oxygen pressure/fraction of inspired oxygen ratio at postoperative day 1 was significantly higher in the Sivelestat-treated group. Serum NE activities and serum concentrations of IL-1beta, IL-6, and HMGB1 were significantly suppressed in the Sivelestat-treated group. Postoperative Sivelestat treatment after transthoracic esophagectomy improves the condition of SIRS and postoperative clinical courses, even in patients without complications.

Role of Toll-like receptor 4 in hyperoxia-induced lung inflammation in mice

OBJECTIVE

Prolonged exposure to hyperoxia causes lung inflammation, but the role of Toll-like receptor 4 (TLR4) in hyperoxia-induced signal transduction remains unclear.

MATERIAL OR SUBJECTS

We evaluated neutrophil accumulation, signal transduction and cytokine production during hyperoxia, comparing TLR4 mutant (C3H/HeJ) and wild type (C3H/HeN) mice.

METHODS

The mice were exposed to 80% oxygen in a hyperoxic chamber for 0 (control), 48, or 96 h. After the exposure, bronchoalveolar lavage (BAL) was performed for differential cell counting and cytokine measurement. In lung homogenate, activation of NF-kappaB and STAT1 was also examined.

RESULTS

In C3H/HeJ mice, hyperoxia-induced neutrophil accumulation in BAL fluid was significantly decreased compared with C3H/HeN. Hyperoxia for 96 h caused NF-kappaB translocation in C3H/HeN mice, which was significantly attenuated in C3H/HeJ mice (p < 0.05). In contrast, STAT1 activation occurred as early as after 48 h of oxygen exposure, which did not differ between the two strains. The levels of TNF-alpha, IL-6, and KC in BAL fluid were increased after oxygen exposure, which was suppressed by the lack of TLR4 signaling.

CONCLUSION

These results suggest that TLR4-dependent NF-kB activation may be an important process of the upregulation of proinflammatory mediators and subsequent neutrophil accumulation into the lung during hyperoxia.

Measurement of atmospheric neutrino flux consistent with tau neutrino appearance

A search for the appearance of tau neutrinos from nu(mu) <--> nu(tau) oscillations in the atmospheric neutrinos has been performed using 1489.2 days of atmospheric neutrino data from the Super-Kamiokande-I experiment. A best fit tau neutrino appearance signal of 138+/-48(stat)-32(+15)(syst) events is obtained with an expectation of 78+/-26(syst). The hypothesis of no tau neutrino appearance is disfavored by 2.4 sigma.

Evidence for an oscillatory signature in atmospheric neutrino oscillations

Muon neutrino disappearance probability as a function of neutrino flight length L over neutrino energy E was studied. A dip in the L/E distribution was observed in the data, as predicted from the sinusoidal flavor transition probability of neutrino oscillation. The observed L/E distribution constrained nu(micro)<-->nu(tau) neutrino oscillation parameters; 1.9x10(-3)<Deltam(2)<3.0x10(-3) eV(2) and sin((2)2theta>0.90 at 90% confidence level.

Limits on the neutrino magnetic moment using 1496 days of Super-Kamiokande-I solar neutrino data

A search for a nonzero neutrino magnetic moment has been conducted using 1496 live days of solar neutrino data from Super-Kamiokande-I. Specifically, we searched for distortions to the energy spectrum of recoil electrons arising from magnetic scattering due to a nonzero neutrino magnetic moment. In the absence of a clear signal, we found micro(nu)</=(3.6x10(-10))micro(B) at 90% C.L. by fitting to the Super-Kamiokande day-night spectra. The fitting took into account the effect of neutrino oscillation on the shapes of energy spectra. With additional information from other solar neutrino and KamLAND experiments constraining the oscillation region, a limit of micro(nu)</=(1.1x10(-10))micro(B) at 90% C.L. was obtained.

Search for nu(e) from the sun at Super-Kamiokande-I

We present the results of a search for low energy nu(e) from the Sun using 1496 days of data from Super-Kamiokande-I. We observe no significant excess of events and set an upper limit for the conversion probability to nu(e) of the 8B solar neutrino. This conversion limit is 0.8% (90% C.L.) of the standard solar model's neutrino flux for total energy=8-20 MeV. We also set a flux limit for monochromatic nu(e) for E(nu(e))=10-17 MeV.

Search for supernova relic neutrinos at Super-Kamiokande

A search for the relic neutrinos from all past core-collapse supernovae was conducted using 1496 days of data from the Super-Kamiokande detector. This analysis looked for electron-type antineutrinos that had produced a positron with an energy greater than 18 MeV. In the absence of a signal, 90% C.L. upper limits on the total flux were set for several theoretical models; these limits ranged from 20 to 130 macro nu(e) cm(-2) s(-1). Additionally, an upper bound of 1.2 macro nu(e) cm(-2) s(-1) was set for the supernova relic neutrino flux in the energy region E(nu)>19.3 MeV.

Constraints on neutrino oscillations using 1258 days of Super-Kamiokande solar neutrino data

We report the result of a search for neutrino oscillations using precise measurements of the recoil electron energy spectrum and zenith angle variations of the solar neutrino flux from 1258 days of neutrino-electron scattering data in Super-Kamiokande. The absence of significant zenith angle variation and spectrum distortion places strong constraints on neutrino mixing and mass difference in a flux-independent way. Using the Super-Kamiokande flux measurement in addition, two allowed regions at large mixing are found.

Solar 8B and hep neutrino measurements from 1258 days of Super-Kamiokande data

Solar neutrino measurements from 1258 days of data from the Super-Kamiokande detector are presented. The measurements are based on recoil electrons in the energy range 5.0-20.0 MeV. The measured solar neutrino flux is 2.32+/-0.03(stat)+0.08-0.07(syst)x10(6) cm(-2) x s(-1), which is 45.1+/-0.5(stat)+1.6-1.4(syst)% of that predicted by the BP2000 SSM. The day vs night flux asymmetry (Phi(n)-Phi(d))/Phi(average) is 0.033+/-0.022(stat)+0.013-0.012(syst). The recoil electron energy spectrum is consistent with no spectral distortion. For the hep neutrino flux, we set a 90% C.L. upper limit of 40x10(3) cm(-2) x s(-1), which is 4.3 times the BP2000 SSM prediction.