Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with 2.2×10^{21} Protons on Target

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×10^{20} protons on target in the neutrino (antineutrino) mode, 89 ν_{e} candidates and seven anti-ν_{e} candidates are observed, while 67.5 and 9.0 are expected for δ_{CP}=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δ_{CP}, does not include the CP-conserving cases (δ_{CP}=0, π). The best-fit values of other parameters are sin^{2}θ_{23}=0.526_{-0.036}^{+0.032} and Δm_{32}^{2}=2.463_{-0.070}^{+0.071}×10^{-3}  eV^{2}/c^{4}.

Oesophagectomy with or without supraclavicular lymphadenectomy after neoadjuvant treatment for squamous cell carcinoma of the oesophagus

Background

Treatment of supraclavicular nodes remains controversial among patients with oesophageal squamous cell carcinoma. This study assessed the outcomes of patients who underwent oesophagectomy with or without supraclavicular lymphadenectomy after neoadjuvant treatment.

Methods

This was a single-centre retrospective cohort study. Patients with oesophageal squamous cell carcinoma and clinically negative supraclavicular nodes who underwent oesophagectomy after neoadjuvant treatment between January 2005 and December 2015 were included. Overall and relapse-free survival were compared between patients who did or did not undergo supraclavicular nodal dissection. Propensity score matching was used to correct for differences in prognostic factors between the groups.

Results

Some 223 patients underwent supraclavicular lymphadenectomy. The prevalence of pathologically confirmed supraclavicular metastasis was 10·3 per cent, and these patients had poor 5-year relapse-free (7 per cent) and overall (14 per cent) survival. Only two of 55 patients who did not undergo supraclavicular lymphadenectomy had recurrent disease in the supraclavicular region without distant metastasis. There was no statistically significant difference between the groups in relapse-free survival (hazard ratio (HR) 0·95, 95 per cent c.i. 0·61 to 1·47; P = 0·821) or overall survival (HR 0·86, 0·52 to 1·40; P = 0·544). Similarly, no significant difference in relapse-free or overall survival was observed between the propensity score-matched groups.

Conclusion

For patients with clinically negative supraclavicular lymph nodes, prophylactic supraclavicular lymphadenectomy may be omitted when neoadjuvant treatment is administered.

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.

Elevation of Autoantibody in Patients with Ischemic Stroke

Recent clinical research has revealed a significant correlation between atherosclerosis, one of the primary etiologies of ischemic stroke, and the immune system. Assuming that "disease-specific autoantibodies are produced in the sera of patients with ischemic stroke," we investigated multiple arteriosclerosis-related antibodies using the serological identification of antigens by recombinant cDNA expression cloning (SEREX), an established method for identifying antigenic proteins. We either screened a human aortic endothelial cell cDNA library or conducted protein array screening using the sera from patients with ischemic stroke, such as carotid artery stenosis or transient ischemic attack (TIA). Next, we measured serum antibody levels using amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) in patient/healthy donor (HD) cohorts and identified several antigens, the antibody levels of which were significantly higher in patients with ischemic stroke than in HDs. This review introduced the method of identifying antigens by the SEREX and protein microarray and summarized antigenic proteins. In particular, it focused on anti-replication protein A2 antibody and anti-programmed cell death 11 antibody, which are significantly related to atherosclerotic plaque and ischemic brain tissue, respectively, and proposed the mechanism of elevated autoantibody levels against them. Furthermore, this review suggests a possibility of clinical application as an atherosclerotic disease diagnostic marker for TIA or cerebral infarction.

Association of serum levels of antibodies against MMP1, CBX1, and CBX5 with transient ischemic attack and cerebral infarction

Transient ischemic attack (TIA) is a predictor for cerebral infarction (CI), and early diagnosis of TIA is extremely important for the prevention of CI. We set out to identify novel antibody biomarkers for TIA and CI, and detected matrix metalloproteinase 1 (MMP1), chromobox homolog 1 (CBX1), and chromobox homolog 5 (CBX5) as candidate antigens using serological identification of antigens by recombinant cDNA expression cloning (SEREX) and Western blotting to confirm the presence of serum antibodies against the antigens. Amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) revealed that serum antibody levels were significantly higher in patients with TIA or acute-phase CI (aCI) compared with healthy donors (P < 0.01). Spearman’s correlation analysis and multivariate logistic regression analysis demonstrated that levels of anti-MMP1, anti-CBX1, and anti-CBX5 antibodies were associated with age, cigarette-smoking habits, and blood pressure. Thus, serum levels of antibodies against MMP1, CBX1, and CBX5 could potentially serve as useful tools for diagnosing TIA and predicting the onset of aCI.

Elevation of autoantibody level against PDCD11 in patients with transient ischemic attack

Background

Disease specific autoantibodies have been detected in the sera of patients with atherosclerosis-related diseases, such as cerebral infarction, cardiovascular disease. In the present study, we aimed to identify novel autoantibodies responsible for transient ischemic attack (TIA), a prodromal condition for cerebral infarction.

Methods

To identify candidate antigens, we screened a human aortic endothelial cell cDNA library using sera from 20 patients with TIA. Serum antibody levels were measured using amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) in 2 independent patient/healthy donor (HD) cohorts (n = 192 and n = 906 in the second screening and validation cohort, respectively).

Results

First screening identified 3 candidate antigens. Of these, programmed cell death 11 (PDCD11) was determined to be associated with stroke (p < 0.0001), as evidenced from the second screening using AlphaLISA. The validation cohort revealed significantly higher antibody levels against PDCD11 (PDCD11-Ab levels) in patients with TIA than in HDs. Multivariate logistic regression analysis indicated that the predictive value of PDCD11-Ab levels for TIA [Odds ratio (OR): 2.44, 95% confidence interval (CI): 1.33-4.57, p = 0.0039] was not inferior to other known risk factors for ischemic stroke, including age (OR: 4.97, 95% CI: 2.67-9.48, p < 0.0001); hypertension (OR: 3.21, 95% CI: 1.76-5.86, p = 0.0001); and diabetes (OR: 4.31, 95% CI: 1.74-11.2, p = 0.0015).

Conclusion

Serum PDCD11-Ab level may serve as a potential biomarker for TIA.

Failure of neoadjuvant chemotherapy for resectable esophageal squamous cell carcinoma

Neoadjuvant treatment has become standard care for patients with resectable esophageal cancer. However, some patients cannot undergo surgery or curative resection because of disease progression during neoadjuvant treatment. The aim of this study is to identify the pretreatment characteristics of patients in whom neoadjuvant treatment failed. The study enrolled 231 patients who underwent chemotherapy with cisplatin and 5-fluorouracil (CF) as neoadjuvant therapy for T1N1-3 or T2-3 any-N esophageal squamous cell carcinoma (ESCC). Of these patients, 201 (87.0%) underwent curative resection (R0) and 30 (13.0%) could not undergo curative resection; 19 patients (8.2%) underwent incomplete resection (R1 or R2), and 11 patients (4.8%) could not undergo surgery because of disease progression. We compared clinical characteristics and survival between patients who underwent curative resection (curative group) and those who could not undergo curative resection (noncurative group) to determine the factors predicting noncurative treatment. The noncurative group had significantly worse disease-specific survival than the curative group (P < 0.001). All patients in the noncurative group had cT3 tumors. In 141 patients with cT3 tumors, those in the noncurative group were more likely to have higher serum SCC antigen concentration (P = 0.021), location of the main tumor in the upper to the middle third of the esophagus (P = 0.071), intramural metastases (P < 0.001), advanced N category (P = 0.016), and bulky lymph node metastases (P = 0.060). Multivariate logistic regression analysis identified location of the main tumor in the upper to the middle third of the esophagus (P = 0.047), intramural metastases (P = 0.002), and nodal metastases (N1, P = 0.014; N2, P = 0.015, respectively) as independent predictors of treatment failure in patients with cT3 tumors. Neoadjuvant CF therapy alone may not be effective for patients with cT3 tumors accompanied by these risk factors, and the efficacy of alternative strategies, such as triplet chemotherapy or chemoradiotherapy, should be evaluated.

Combined Analysis of Neutrino and Antineutrino Oscillations at T2K

T2K reports its first results in the search for CP violation in neutrino oscillations using appearance and disappearance channels for neutrino- and antineutrino-mode beams. The data include all runs from January 2010 to May 2016 and comprise 7.482×10^{20} protons on target in neutrino mode, which yielded in the far detector 32 e-like and 135  μ-like events, and 7.471×10^{20} protons on target in antineutrino mode, which yielded 4 e-like and 66  μ-like events. Reactor measurements of sin^{2}2θ_{13} have been used as an additional constraint. The one-dimensional confidence interval at 90% for the phase δ_{CP} spans the range (-3.13, -0.39) for normal mass ordering. The CP conservation hypothesis (δ_{CP}=0, π) is excluded at 90% C.L.

Measurement of Coherent π^{+} Production in Low Energy Neutrino-Carbon Scattering

We report the first measurement of the flux-averaged cross section for charged current coherent π^{+} production on carbon for neutrino energies less than 1.5 GeV, and with a restriction on the final state phase space volume in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. We observe a clear event excess above background, disagreeing with the null results reported by K2K and SciBooNE in a similar neutrino energy region. The measured flux-averaged cross sections are below those predicted by both the Rein-Sehgal and Alvarez-Ruso et al.

Role of Prealbumin as a Powerful and Simple Index for Predicting Postoperative Complications After Gastric Cancer Surgery

BACKGROUND

Preoperative factors, including nutritional status, may have strong correlations with postoperative morbidities. The current study evaluated preoperative prealbumin concentrations as a predictor of postoperative complications after gastric surgery.

METHODS

A retrospective study of 1798 patients who underwent gastrectomy for gastric adenocarcinoma was performed. Information was collected on basic patient characteristics, preoperative laboratory findings, and 30 day postoperative complications. The patients were divided into three groups based on prealbumin concentrations (≥22 mg/dL, <22 to ≥15 mg/dL, and <15 mg/dL) for analysis.

RESULTS

The overall complication rate was 21.7 %, and the infection rate was 16 %. Subgroup analysis based on prealbumin concentrations showed that complication rates were markedly elevated with decreasing concentrations of prealbumin. Multivariate analysis using a logistic regression model showed that both overall and infectious complications were strongly associated with male gender, elevated C-reactive protein (CRP), and decreased prealbumin levels (p < 0.05). Even in patients with a CRP level higher than 0.1 mg/dL, male gender and low prealbumin concentrations (<15 mg/dL) were significantly correlated with overall and infectious morbidities (p < 0.05).

CONCLUSIONS

Preoperative prealbumin concentrations are useful predictors of short-term postoperative outcomes after gastrectomy.

Angioarchitecture Predicting Hemorrhage in Cerebral Arteriovenous Malformations

To find out lesions responsible for hemorrhage in arteriovenous malformations (AVMs), a retrospective study of angioarchitecture around the nidus was conducted in 27 patients who underwent conservative treatment. Comparison of angiograms revealed disappearance of an intranidal aneurysmal dilatation after the hemorrhagic events in two cases. The hematomas were adjacent to the dilatation, and no subarachnoid hemorrhage was evident. Obstruction of venous drainage, noticed in a case of spontaneous regression of AVM, was not demonstrated in the cases of hemorrhage.

The intranidal aneurysmal dilatation is likely to have caused the hemorrhage in our cases. Careful endavascular embolization using proper materials should be indicated for an intranidal aneurysmal dilatation to prevent subsequent hemorrhage.

Measurement of Muon Antineutrino Oscillations with an Accelerator-Produced Off-Axis Beam

T2K reports its first measurements of the parameters governing the disappearance of ν[over ¯]_{μ} in an off-axis beam due to flavor change induced by neutrino oscillations. The quasimonochromatic ν[over ¯]_{μ} beam, produced with a peak energy of 0.6 GeV at J-PARC, is observed at the far detector Super-Kamiokande, 295 km away, where the ν[over ¯]_{μ} survival probability is expected to be minimal. Using a data set corresponding to 4.01×10^{20} protons on target, 34 fully contained μ-like events were observed. The best-fit oscillation parameters are sin^{2}(θ[over ¯]_{23})=0.45 and |Δm[over ¯]_{32}^{2}|=2.51×10^{-3}  eV^{2} with 68% confidence intervals of 0.38-0.64 and 2.26-2.80×10^{-3}  eV^{2}, respectively. These results are in agreement with existing antineutrino parameter measurements and also with the ν_{μ} disappearance parameters measured by T2K.

Long-term outcome of esophagectomy for primary malignant melanoma of the esophagus: a single-institute retrospective analysis

Primary malignant melanoma of the esophagus (PMME) is a highly malignant tumor with a poor prognosis. Because PMME is an extremely rare disease, therapeutic strategies against the tumor have yet to be established, and the efficacy of esophagectomy remains unclear. The objective of this study was to evaluate the post-esophagectomy survival of PMME patients. Ten patients who underwent esophagectomy for PMME between March 2005 and April 2013 at the Department of Gastroenterological Surgery, Cancer Institute Hospital, Tokyo, Japan, were identified from the institutional database. We retrospectively retrieved clinical information and data on the long-term outcomes from the patients' records. Survival rates after esophagectomy were calculated by the Kaplan-Meier method, and the hazard ratios of mortality were determined using the Cox's model. A follow-up study of the 10 patients revealed 7 cancer recurrences and 5 deaths. Median survival time was 34.5 months, and 5 of 10 patients survived longer than 2 years. The 1-year disease-free survival rate was 40%, and the 1- and 3-year overall survival rates were 70% and 60%, respectively. Importantly, all three of the non-relapsing patients were histologically confirmed as free of lymph node involvement. The four patients with lymph node metastasis relapsed within 1 year. The disease-free survival was significantly shorter in patients with lymph node involvement than in those without lymph node involvement (univariate hazard ratio = 13.3, 95% confidence interval 1.85-266.4; P = 0.009). In conclusion, esophagectomy might benefit PMME patients with no lymph node metastasis. Further large-scale cohort studies are needed to establish the treatment strategy for PMME.

Elevated Adiponectin Antibody Levels in Sera of Patients with Atherosclerosis-Related Coronary Artery Disease, Cerebral Infarction and Diabetes Mellitus

Adiponectin secreted from the adipocytes plays pleiotropic, anti-atherosclerotic roles, such as enhancement of insulin secretion and an increase in energy expenditure. The measurement of levels of circulating adiponectin is useful to evaluate the progression of atherosclerosis-related diseases, such as coronary artery disease (CAD), cerebral infarction (CI) and diabetes mellitus (DM). We examined the serum antibody levels against recombinant adiponectin protein via the amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) method. The results revealed that the antibody levels were significantly higher in patients with CAD, CI and type 2 DM, than in healthy donors. Receiver operating curve analysis showed that the sensitivity was in a range of 41–48% for CAD, CI and DM. Thus, the serum anti-adiponectin antibody levels could be a common marker for atherosclerosis-related diseases.

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.