Direct Measurement of the Spectral Structure of Cosmic-Ray Electrons+Positrons in the TeV Region with CALET on the International Space Station

Detailed measurements of the spectral structure of cosmic-ray electrons and positrons from 10.6 GeV to 7.5 TeV are presented from over 7 years of observations with the CALorimetric Electron Telescope (CALET) on the International Space Station. The instrument, consisting of a charge detector, an imaging calorimeter, and a total absorption calorimeter with a total depth of 30 radiation lengths at normal incidence and a fine shower imaging capability, is optimized to measure the all-electron spectrum well into the TeV region. Because of the excellent energy resolution (a few percent above 10 GeV) and the outstanding e/p separation (10^{5}), CALET provides optimal performance for a detailed search of structures in the energy spectrum. The analysis uses data up to the end of 2022, and the statistics of observed electron candidates has increased more than 3 times since the last publication in 2018. By adopting an updated boosted decision tree analysis, a sufficient proton rejection power up to 7.5 TeV is achieved, with a residual proton contamination less than 10%. The observed energy spectrum becomes gradually harder in the lower energy region from around 30 GeV, consistently with AMS-02, but from 300 to 600 GeV it is considerably softer than the spectra measured by DAMPE and Fermi-LAT. At high energies, the spectrum presents a sharp break around 1 TeV, with a spectral index change from -3.15 to -3.91, and a broken power law fitting the data in the energy range from 30 GeV to 4.8 TeV better than a single power law with 6.9 sigma significance, which is compatible with the DAMPE results. The break is consistent with the expected effects of radiation loss during the propagation from distant sources (except the highest energy bin). We have fitted the spectrum with a model consistent with the positron flux measured by AMS-02 below 1 TeV and interpreted the electron+positron spectrum with possible contributions from pulsars and nearby sources. Above 4.8 TeV, a possible contribution from known nearby supernova remnants, including Vela, is addressed by an event-by-event analysis providing a higher proton-rejection power than a purely statistical analysis.

Long-Term Results of a Multi-Institutional Study of Dynamic Tumor Tracking-Stereotactic Body Radiotherapy for Lung Tumors

PURPOSE/OBJECTIVE(S)

We had conducted a multi-institutional phase II study to evaluate the safety and efficacy of dynamic tumor tracking-stereotactic body radiotherapy (DTT-SBRT) for lung tumors. The primary endpoint was 2-year local control, which was reported to be 95.2%. After the initial evaluation of the primary endpoint, the study was extended as an observational study which was designed to evaluate 5-year survival and late toxicities. We present the long-term results of DTT-SBRT for lung tumors.

MATERIALS/METHODS

The main eligibility criteria for the study were as follows: (1) primary or metastatic lung cancer with a diameter of 5 cm or less, and up to 3 lesions without any extrapulmonary lesions; (2) ineligibility to standard surgery, or patient's refusal of surgery; (3) ECOG-PS of 0 to 2; and (4) expected range of respiratory motion of 10 mm or more. The study included 48 patients from four institutions with the median age of 80 years (range, 49-90 years). Forty-two patients had primary non-small-cell lung cancer, and 6 patients had metastatic lung tumors. Forty-eight tumors (median diameter, 23.5 mm; range, 5-47 mm) in 48 patients were targeted for DTT-SBRT using a gimbal-mounted linear accelerator. Prior to treatment planning, spherical gold markers were placed around the tumor to detect internal tumor motion using fluoroscopy. The prescribed dose was 50 Gy in four fractions. Treatment beams were delivered with DTT according to a 4D model that predicts internal tumor motion with abdominal wall motion. DTT-SBRT was successfully delivered to all but one patient who had poor correlation between abdominal wall and tumor motion.

RESULTS

Median follow-up period at data cutoff was 5.0 years (interquartile range, 3.1-6.3 years). Twenty-nine patients died; the causes of death were cancer-specific in 10 patients, comorbidity in 14 patients (pulmonary disease, renal failure, cerebral infarction, other malignancies, etc.), and unknown in 5 patients without cancer recurrence. Overall survival at 5 years was 51.5% (95% confidence interval [CI], 36.5-64.6%). Progression-free survival and local control at 5 years were 41.0% (95% CI, 27.0-54.5%) and 92.6% (95% CI, 78.7-97.6%), respectively. There were no grade 4-5 toxicities. One patient (2%) developed grade 3 radiation pneumonitis at 3 months. Grade 2 toxicities were observed in 9 patients (19%), including dyspnea, radiation pneumonitis, pleural effusion, rib fracture, and dermatitis.

CONCLUSION

Dynamic tumor tracking SBRT achieved the long-term efficacy with low incidence of severe toxicities in lung tumors with respiratory motion. In this elderly patient cohort, non-cancer deaths were observed more than cancer-specific deaths.

Major Cardiovascular Events after Chemoradiotherapy with or without Durvalumab in Patients with Stage III Non-Small Cell Lung Cancer: Supplementary Analysis

PURPOSE/OBJECTIVE(S)

RTOG 0617 showed that cardiac events are relatively common after high-dose thoracic radiotherapy. The aim of this study was to investigate the incidence and risk of major cardiovascular events (MACE) after concurrent chemoradiotherapy (CCRT) with or without durvalumab in patients with stage III non-small cell lung cancer (NSCLC) using the data from a multi-institutional study in Japan.

MATERIALS/METHODS

Patients who received CCRT for stage III NSCLC between July 2018 and July 2019 were enrolled in a multi-institutional study in Japan. MACE was defined as follows: symptomatic pericardial effusion, acute coronary syndrome, pericarditis, significant arrhythmia, and heart failure. The cumulative incidence of MACE, accounting for death as a competing risk, was calculated. Pre-existing coronary heart disease (CHD) included coronary artery disease, congestive heart failure, peripheral vascular disease, stroke, and extensive coronary artery calcification. The association between patient/treatment-related factors and MACE was assessed by multivariate analysis.

RESULTS

Among 178 patients with a median follow-up period of 42.5 months, 13 patients developed MACEs. The 3-year cumulative incidence of MACE was 6.9% (95% confidence interval [CI], 4.0-11.9%). Univariate analysis showed that female sex and mean heart dose (MHD) were marginally associated (3-year cumulative incidence, male 5.6% vs. female 12.1%; P = 0.12; MHD ≥ 6.3 Gy 4.8% vs. < 6.3 Gy 9.1%; P = 0.13), and pre-existing CHD was significantly associated with an increased risk of MACE (no CHD 4.3% vs. CHD 16.8%; P = 0.026). Consolidation durvalumab was not associated with an increased risk of MACE (no durvalumab 5.2% vs. durvalumab 7.4%; P = 0.89). Multivariate analysis showed that pre-existing CHD was significantly associated with MACE (hazard ratio, 4.22; 95% CI, 1.30-13.7; P = 0.016).

CONCLUSION

The incidence of MACE based on the real-world data in Japan was lower than previously reported. Pre-existing CHD was associated with an increased risk of MACE after CCRT in patients with stage III NSCLC, whereas the administration of consolidation durvalumab was not associated with an increased risk of MACE.

Real-World Study of Overall Survival in Patients with Stage III Non-Small Cell Lung Cancer Treated with Chemoradiotherapy with or without Durvalumab and an Exploratory Analysis of Effective Radiation Dose to the Immune Cells

PURPOSE/OBJECTIVE(S)

To investigate the real-world data on overall survival (OS) in patients with stage III non-small cell lung cancer (NSCLC) treated with concurrent chemoradiotherapy (CCRT) with or without consolidation durvalumab, and to perform an exploratory analysis on effective radiation dose to the immune cells (EDIC).

MATERIALS/METHODS

In our multi-institutional retrospective study, patients who received CCRT between July 2018 and July 2019 for stage III NSCLC in Japan were investigated. EDIC was estimated using mean lung dose, mean heart dose, body volume, body mean dose, and body weight, as reported in the secondary analysis of RTOG 0617. The cut-off value of EDIC was calculated using the maximally selected log-rank statistics.

RESULTS

One hundred and seventy-eight patients were eligible for the analysis (136 patients, CCRT with consolidation durvalumab [CCRT+D] cohort; 42 patients, CCRT cohort). The median follow-up period was 42.5 months. Three-year OS rates were 59.8% in the overall cohort: 60.5% in the CCRT+D cohort, and 58.0% in the CCRT cohort with no significant difference (hazard ratio [HR], 0.76; 95% confidence interval [CI], 0.45-1.27; P = 0.29). Univariate analysis showed that ECOG-PS, smoking history, histology, EGFR mutational status, gross tumor volume and EDIC were significantly associated with OS. Multivariate analysis showed that ECOG-PS 2, gross tumor volume ≥ 57 cm3 and EDIC ≥ 4.4 Gy were associated with poor OS. Among 21 EGFR-mutated patients, 3 year-OS rates were 64.7% in the CCRT+D cohort and 100% in the CCRT cohort, while 3 year-OS rates were 68.8% and 58.7% among 90 EGFR wild-type patients. Three-year OS rates were 64.6% and 47.6% for EDIC < 4.4 Gy and EDIC ≥ 4.4 Gy in the overall cohort (HR, 1.82; 95% CI, 1.14-2.90; P = 0.015). In the subgroup analysis, 66.3% vs. 44.4% in the CCRT+D cohort (HR, 2.01; 95% CI, 1.17-3.47; P = 0.016), and 59.0% vs. 56.1% in the CCRT cohort (HR, 1.20; 95% CI, 0.48-3.01; P = 0.70), respectively.

CONCLUSION

Our real-world data in Japan showed that there was no significant difference in OS between the CCRT+D cohort and the CCRT cohort. High EDIC could be a risk for poor OS in patients treated with CCRT and consolidation durvalumab compared with those treated with CCRT.

Erratum: Charge-Sign Dependent Cosmic-Ray Modulation Observed with the Calorimetric Electron Telescope on the International Space Station [Phys. Rev. Lett. 130, 211001 (2023)]

This corrects the article DOI: 10.1103/PhysRevLett.130.211001.

Charge-Sign Dependent Cosmic-Ray Modulation Observed with the Calorimetric Electron Telescope on the International Space Station

We present the observation of a charge-sign dependent solar modulation of galactic cosmic rays (GCRs) with the Calorimetric Electron Telescope onboard the International Space Station over 6 yr, corresponding to the positive polarity of the solar magnetic field. The observed variation of proton count rate is consistent with the neutron monitor count rate, validating our methods for determining the proton count rate. It is observed by the Calorimetric Electron Telescope that both GCR electron and proton count rates at the same average rigidity vary in anticorrelation with the tilt angle of the heliospheric current sheet, while the amplitude of the variation is significantly larger in the electron count rate than in the proton count rate. We show that this observed charge-sign dependence is reproduced by a numerical "drift model" of the GCR transport in the heliosphere. This is a clear signature of the drift effect on the long-term solar modulation observed with a single detector.

Direct Measurement of the Cosmic-Ray Helium Spectrum from 40 GeV to 250 TeV with the Calorimetric Electron Telescope on the International Space Station

We present the results of a direct measurement of the cosmic-ray helium spectrum with the CALET instrument in operation on the International Space Station since 2015. The observation period covered by this analysis spans from October 13, 2015, to April 30, 2022 (2392 days). The very wide dynamic range of CALET allowed for the collection of helium data over a large energy interval, from ∼40  GeV to ∼250  TeV, for the first time with a single instrument in low Earth orbit. The measured spectrum shows evidence of a deviation of the flux from a single power law by more than 8σ with a progressive spectral hardening from a few hundred GeV to a few tens of TeV. This result is consistent with the data reported by space instruments including PAMELA, AMS-02, and DAMPE and balloon instruments including CREAM. At higher energy we report the onset of a softening of the helium spectrum around 30 TeV (total kinetic energy). Though affected by large uncertainties in the highest energy bins, the observation of a flux reduction turns out to be consistent with the most recent results of DAMPE. A double broken power law is found to fit simultaneously both spectral features: the hardening (at lower energy) and the softening (at higher energy). A measurement of the proton to helium flux ratio in the energy range from 60  GeV/n to about 60  TeV/n is also presented, using the CALET proton flux recently updated with higher statistics.

Cosmic-Ray Boron Flux Measured from 8.4 GeV/n to 3.8 TeV/n with the Calorimetric Electron Telescope on the International Space Station

We present the measurement of the energy dependence of the boron flux in cosmic rays and its ratio to the carbon flux in an energy interval from 8.4  GeV/n to 3.8  TeV/n based on the data collected by the Calorimetric Electron Telescope (CALET) during ∼6.4  yr of operation on the International Space Station. An update of the energy spectrum of carbon is also presented with an increase in statistics over our previous measurement. The observed boron flux shows a spectral hardening at the same transition energy E_{0}∼200  GeV/n of the C spectrum, though B and C fluxes have different energy dependences. The spectral index of the B spectrum is found to be γ=-3.047±0.024 in the interval 25<E<200  GeV/n. The B spectrum hardens by Δγ_{B}=0.25±0.12, while the best fit value for the spectral variation of C is Δγ_{C}=0.19±0.03. The B/C flux ratio is compatible with a hardening of 0.09±0.05, though a single power-law energy dependence cannot be ruled out given the current statistical uncertainties. A break in the B/C ratio energy dependence would support the recent AMS-02 observations that secondary cosmic rays exhibit a stronger hardening than primary ones. We also perform a fit to the B/C ratio with a leaky-box model of the cosmic-ray propagation in the Galaxy in order to probe a possible residual value λ_{0} of the mean escape path length λ at high energy. We find that our B/C data are compatible with a nonzero value of λ_{0}, which can be interpreted as the column density of matter that cosmic rays cross within the acceleration region.

Observation of Spectral Structures in the Flux of Cosmic-Ray Protons from 50 GeV to 60 TeV with the Calorimetric Electron Telescope on the International Space Station

A precise measurement of the cosmic-ray proton spectrum with the Calorimetric Electron Telescope (CALET) is presented in the energy interval from 50 GeV to 60 TeV, and the observation of a softening of the spectrum above 10 TeV is reported. The analysis is based on the data collected during ∼6.2  years of smooth operations aboard the International Space Station and covers a broader energy range with respect to the previous proton flux measurement by CALET, with an increase of the available statistics by a factor of ∼2.2. Above a few hundred GeV we confirm our previous observation of a progressive spectral hardening with a higher significance (more than 20 sigma). In the multi-TeV region we observe a second spectral feature with a softening around 10 TeV and a spectral index change from -2.6 to -2.9 consistently, within the errors, with the shape of the spectrum reported by DAMPE. We apply a simultaneous fit of the proton differential spectrum which well reproduces the gradual change of the spectral index encompassing the lower energy power-law regime and the two spectral features observed at higher energies.

Rapid quasi-periodic oscillations in the relativistic jet of BL Lacertae

Blazars are active galactic nuclei (AGN) with relativistic jets whose non-thermal radiation is extremely variable on various timescales^1-3. This variability seems mostly random, although some quasi-periodic oscillations (QPOs), implying systematic processes, have been reported in blazars and other AGN. QPOs with timescales of days or hours are especially rare⁴ in AGN and their nature is highly debated, explained by emitting plasma moving helically inside the jet⁵, plasma instabilities^6,7 or orbital motion in an accretion disc^7,8. Here we report results of intense optical and γ-ray flux monitoring of BL Lacertae (BL Lac) during a dramatic outburst in 2020 (ref. ⁹). BL Lac, the prototype of a subclass of blazars¹⁰, is powered by a 1.7 × 10⁸ M_Sun (ref. ¹¹) black hole in an elliptical galaxy (distance = 313 megaparsecs (ref. ¹²)). Our observations show QPOs of optical flux and linear polarization, and γ-ray flux, with cycles as short as approximately 13 h during the highest state of the outburst. The QPO properties match the expectations of current-driven kink instabilities⁶ near a recollimation shock about 5 parsecs (pc) from the black hole in the wake of an apparent superluminal feature moving down the jet. Such a kink is apparent in a microwave Very Long Baseline Array (VLBA) image.

Direct Measurement of the Nickel Spectrum in Cosmic Rays in the Energy Range from 8.8 GeV/n to 240 GeV/n with CALET on the International Space Station

The relative abundance of cosmic ray nickel nuclei with respect to iron is by far larger than for all other transiron elements; therefore it provides a favorable opportunity for a low background measurement of its spectrum. Since nickel, as well as iron, is one of the most stable nuclei, the nickel energy spectrum and its relative abundance with respect to iron provide important information to estimate the abundances at the cosmic ray source and to model the Galactic propagation of heavy nuclei. However, only a few direct measurements of cosmic-ray nickel at energy larger than ∼3  GeV/n are available at present in the literature, and they are affected by strong limitations in both energy reach and statistics. In this Letter, we present a measurement of the differential energy spectrum of nickel in the energy range from 8.8  to 240  GeV/n, carried out with unprecedented precision by the Calorimetric Electron Telescope (CALET) in operation on the International Space Station since 2015. The CALET instrument can identify individual nuclear species via a measurement of their electric charge with a dynamic range extending far beyond iron (up to atomic number Z=40). The particle's energy is measured by a homogeneous calorimeter (1.2 proton interaction lengths, 27 radiation lengths) preceded by a thin imaging section (3 radiation lengths) providing tracking and energy sampling. This Letter follows our previous measurement of the iron spectrum [1O. Adriani et al. (CALET Collaboration), Phys. Rev. Lett. 126, 241101 (2021).PRLTAO0031-900710.1103/PhysRevLett.126.241101], and it extends our investigation on the energy dependence of the spectral index of heavy elements. It reports the analysis of nickel data collected from November 2015 to May 2021 and a detailed assessment of the systematic uncertainties. In the region from 20 to 240  GeV/n our present data are compatible within the errors with a single power law with spectral index -2.51±0.07.

Percutaneous coronary intervention on combined VA-ECMO and IMPELLA (ECPELLA) support may reduce myocardial damage in cardiogenic shock patients with STEMI who required mechanical circulatory support

Background

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is an effective therapeutic modality for patients with cardiogenic shock (CS) including STEMI. The VA-ECMO maintains end-organ perfusion, however, it significantly increases damaged left ventricular (LV) afterload. Combined treatment of VA-ECMO and a micro-axial Impella pump, ECPELLA, simultaneously provides systemic circulatory support and LV loading reduction (LV unloading). Studies in ischemic animal models displayed that LV unloading reduced myocardial size. However, it remains unknown whether LV unloading effect by ECPELLA during percutaneous coronary intervention (PCI) can reduce myocardial damage in human STEMI patients with severe cardiogenic shock.

Purpose

This study was to assess whether PCI on ECPELLA support can reduce myocardial damage in STEMI patients with severe cardiogenic shock.

Methods

Sixteen consecutive patients with STEMI and lethal CS (SCAI stage E) were enrolled. All patients suffered from cardiac arrest. Fifteen patients (94%) underwent extracorporeal cardiopulmonary resuscitation using VA-ECMO. From October 2018 to November 2019, PCI was carried out on VA-ECMO support and the mechanical circulatory support (MCS) modality during PCI was switched to ECPELLA since December 2019. There were 8 patients who underwent PCI on ECPELLA support (ECPELLA-PCI) and 8 patients who underwent PCI on single VA-ECMO support (ECMO-PCI). All patients in ECMO-PCI group were escalated to ECPELLA after PCI. Therefore, the difference between groups was timing of LV unloading, i.e., pre-PCI or post-PCI condition. We assessed total MCS flow during PCI, and peak and time course changes in CK-MB levels from days 0 to 3.

Results

There were no significant differences in age, rate of male sex, body surface area, shockable rhythm, serum lactate levels, and door to MCS time. Patients in ECPELLA-PCI had significantly longer door to recanalization time (73min in ECPELLA vs. 49min in VA-ECMO, p&lt;0.05), and higher total MCS flow during PCI (3.1 L/min/sqM vs. 2.0 L/min/sqM, p&lt;0.05). Peak and the area under the curves (AUC) from day 0 to day 3 of CK-MB in ECPELLA-PCI were significantly lower than ECMO-PCI group (peak CK-MB 120 vs. 524 IU/L and CK-MB AUC 143 vs. 464 IU/L*Day, respectively, p&lt;0.05). While all patients received red blood cell (RBC) and plasma (PL) transfusions, ECPELLA-PCI required larger amount of RBC and PL transfusions (p&lt;0.05).

Conclusion

The ECPELLA-PCI appeared to reduce myocardial damage shown by peak and AUC of CK-MB levels. Lager amount of blood transfusion is a major drawback of this treatment modality. Further studies are necessary whether ECPELLA-PCI is an effective revascularization approach for myocardial damage reduction with favorable mid- and long-term outcome in patients with STEMI with severe cardiogenic shock.

Funding Acknowledgement

Type of funding sources: None. Total MCS FLow and Ttoal MCS flow indexPeak CK-MB and CK-MB AUC

The effectiveness of strict low-density lipoprotein cholesterol management in secondary prevention of Japanese patients

Background

In Japanese guidelines, target value of low-density lipoprotein cholesterol (LDL-C) &lt;100mg/dL is recommended as standard management for secondary prevention of coronary artery disease. On the other hand, the guidelines also state that LDL-C targeting &lt;70mg/dL should be considered in high-risk patients. However, the effectiveness of strict LDL-C management in the prevention of long-term coronary event recurrence in Japanese patients remains unclear.

Purpose

The purpose of the present study was to evaluate whether the strict management of LDL-C targeting &lt;70 mg/dL was effective to prevent recurrence of acute coronary syndrome (ACS) than standard management in patients with previous percutaneous coronary intervention (PCI).

Methods

From January 2007 to August 2020, we performed coronary angiography in 359 patients with previous PCI who were suspected of having signs of recurrent cardiac ischemia. Patients were stratified into three groups according to achieved LDL-C value; &lt;70mg/dL (n=57), 70 to &lt;100mg/dL (n=135) and ≥100mg/dL (n=167). In addition, patients who had previous ACS and/or diabetes mellitus were defined as high-risk group, and sub-analysis by their achieved LDL-C values was performed in high-risk group and non-high-risk group. Endpoint was recurrence of ACS. Moreover, risk factors associated with recurrent-ACS were examined in patients with LDL-C &lt;100 mg/dL.

Results

After follow-up (median 6.1 years), 99 patients (28%) had recurrent-ACS. Recurrent-ACS was significantly lower in patients with LDL-C &lt;70mg/dL than LDL-C 70 to &lt;100mg/dL and LDL-C ≥100mg/dL (p&lt;0.01 and p&lt;0.001, respectively). In sub-analysis, high-risk group with LDL-C &lt;70 mg/dL had lower incidence of recurrent-ACS than LDL-C 70 to &lt;100 mg/dL (p=0.03). Similar tendency was found in non-high-risk group (p=0.08). There was no difference of recurrent-ACS between high-risk group and non-high-risk group in patients with LDL-C &lt;70mg/dL (p=0.41). Moreover, in patients with achieved LDL-C &lt;100mg/dL (n=192), multivariate analysis identified that LDL-C (HR: 1.032, p&lt;0.01) and HbA1c (HR: 1.330, p&lt;0.01) were independent predictors of recurrent-ACS. In these patients, whether or not they were in the high-risk group was not a significant predictor (p=0.61).

Conclusions

Strict management of LDL-C targeting &lt;70 mg/dL should be considered for a wider range of Japanese patients as well as for Westerners to prevent recurrence of ACS in secondary prevention.

Funding Acknowledgement

Type of funding sources: None. Probability of freedom from ACS

High spatial-density, cladding-pumped 6-mode 7-core fiber amplifier for C-band operation

We present a C-band 6-mode 7-core fiber amplifier in an all-fiberized cladding-pumped configuration for space division multiplexed transmission supporting a record 42 spatial channels. With optimized fiber components (e.g. passively cooled pump laser diode, pump coupler, pump stripper), high power multimode pump light is coupled to the active fiber without any noticeable thermal degradation and an average gain of 18 dB and noise figure of 5.4 dB are obtained with an average differential modal gain of 3.4 dB.

Measurement of the Iron Spectrum in Cosmic Rays from 10 GeV/n to 2.0 TeV/n with the Calorimetric Electron Telescope on the International Space Station

The Calorimetric Electron Telescope (CALET), in operation on the International Space Station since 2015, collected a large sample of cosmic-ray iron over a wide energy interval. In this Letter a measurement of the iron spectrum is presented in the range of kinetic energy per nucleon from 10  GeV/n to 2.0  TeV/n allowing the inclusion of iron in the list of elements studied with unprecedented precision by space-borne instruments. The measurement is based on observations carried out from January 2016 to May 2020. The CALET instrument can identify individual nuclear species via a measurement of their electric charge with a dynamic range extending far beyond iron (up to atomic number Z=40). The energy is measured by a homogeneous calorimeter with a total equivalent thickness of 1.2 proton interaction lengths preceded by a thin (3 radiation lengths) imaging section providing tracking and energy sampling. The analysis of the data and the detailed assessment of systematic uncertainties are described and results are compared with the findings of previous experiments. The observed differential spectrum is consistent within the errors with previous experiments. In the region from 50  GeV/n to 2  TeV/n our present data are compatible with a single power law with spectral index -2.60±0.03.

Comparison of postoperative infection after emergency inguinal hernia surgery with enterectomy between mesh repair and non-mesh repair: a national database analysis

PURPOSE

Synthetic non-absorbable mesh is used for elective inguinal hernia repair but is not commonly used for incarcerated or strangulated inguinal hernia requiring enterectomy to reduce the risk of surgical-site infection. This study aimed to evaluate the safety of synthetic non-absorbable mesh repair in patients with incarcerated or strangulated inguinal hernia requiring enterectomy versus non-mesh repair.

METHODS

We analyzed patients with incarcerated or strangulated inguinal hernia with enterectomy from April 2012 to March 2017 using a nationwide inpatient database in Japan. We conducted overlap propensity score-weighted analyses to compare surgical-site infection (SSI), duration of anesthesia, antibiotic use at > 3 days after surgery, postoperative hospital stay, and 30 day readmission. Two sensitivity analyses were performed. First, we compared the proportions of patients requiring wound culture at ≥ 3 days after surgery. Second, we performed overlap propensity score-weighted logistic regression analyses for surgical-site infection.

RESULTS

We identified 668 eligible patients, comprising 223 patients with mesh repair and 445 with non-mesh repair. Overlap propensity score-weighted analyses showed no significant differences between the mesh repair and non-mesh repair groups for SSI (2.5 vs. 2.8%, P = 0.79). Secondary outcomes did not differ significantly between the groups. Proportion of wound culture at ≥ 3 days after surgery was similar in the two groups (11.1 vs. 14.6%, P = 0.18). Logistic regression analysis showed no significant association between mesh repair and SSI (odds ratio, 0.93; 95% confidence interval, 0.34-2.57).

CONCLUSION

Synthetic non-absorbable mesh use may be safe for incarcerated or strangulated inguinal hernia requiring enterectomy.

Difference in surgical outcomes of rectal cancer by study design: meta-analyses of randomized clinical trials, case-matched studies, and cohort studies

Background

RCTs are considered the standard in surgical research, whereas case-matched studies and propensity score matching studies are conducted as an alternative option. Both study designs have been used to investigate the potential superiority of robotic surgery over laparoscopic surgery for rectal cancer. However, no conclusion has been reached regarding whether there are differences in findings according to study design. This study aimed to examine similarities and differences in findings relating to robotic surgery for rectal cancer by study design.

Methods

A comprehensive literature search was conducted using PubMed, Scopus, and Cochrane CENTRAL to identify RCTs, case-matched studies, and cohort studies that compared robotic versus laparoscopic surgery for rectal cancer. Primary outcomes were incidence of postoperative overall complications, incidence of anastomotic leakage, and postoperative mortality. Meta-analyses were performed for each study design using a random-effects model.

Results

Fifty-nine articles were identified and reviewed. No differences were observed in incidence of anastomotic leakage, mortality, rate of positive circumferential resection margins, conversion rate, and duration of operation by study design. With respect to the incidence of postoperative overall complications and duration of hospital stay, the superiority of robotic surgery was most evident in cohort studies (risk ratio (RR) 0.83, 95 per cent c.i. 0.74 to 0.92, P < 0.001; mean difference (MD) –1.11 (95 per cent c.i. –1.86 to –0.36) days, P = 0.004; respectively), and least evident in RCTs (RR 1.12, 0.91 to 1.38, P = 0.27; MD –0.28 (–1.44 to 0.88) days, P = 0.64; respectively).

Conclusion

Results of case-matched studies were often similar to those of RCTs in terms of outcomes of robotic surgery for rectal cancer. However, case-matched studies occasionally overestimated the effects of interventions compared with RCTs.

Direct Measurement of the Cosmic-Ray Carbon and Oxygen Spectra from 10 GeV/n to 2.2 TeV/n with the Calorimetric Electron Telescope on the International Space Station

In this paper, we present the measurement of the energy spectra of carbon and oxygen in cosmic rays based on observations with the Calorimetric Electron Telescope on the International Space Station from October 2015 to October 2019. Analysis, including the detailed assessment of systematic uncertainties, and results are reported. The energy spectra are measured in kinetic energy per nucleon from 10  GeV/n to 2.2  TeV/n with an all-calorimetric instrument with a total thickness corresponding to 1.3 nuclear interaction length. The observed carbon and oxygen fluxes show a spectral index change of ∼0.15 around 200  GeV/n established with a significance >3σ. They have the same energy dependence with a constant C/O flux ratio 0.911±0.006 above 25  GeV/n. The spectral hardening is consistent with that measured by AMS-02, but the absolute normalization of the flux is about 27% lower, though in agreement with observations from previous experiments including the PAMELA spectrometer and the calorimetric balloon-borne experiment CREAM.