Identification of ovarian endometriotic cysts in cystic lesions of the ovary by amide proton transfer-weighted imaging and R2∗ mapping

AIM

To investigate the value of amide proton transfer weighted (APTw) imaging and R2∗ mapping of cystic fluid in differentiating ovarian endometriotic cysts (OE) from other ovarian cystic (OOC) lesions.

MATERIALS AND METHODS

A total of 42 patients who underwent 3 T pelvic magnetic resonance imaging (MRI) were enrolled. Nineteen lesions were OE and 27 lesions were OOC. The APTw imaging and R2∗ values of the cystic fluid were measured and compared between the two groups using the independent sample t-test or Mann-Whitney U-test. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic efficacy of different parameters. The area under ROC curves (AUCs) was compared using the Delong test. Spearman's correlation analysis was used to assess the correlation between APTw imaging and R2∗ values.

RESULTS

APTw imaging values of OE were lower, while R2∗ values were higher in OE than those in OOC (p=0.001 and < 0.001). The AUCs of APTw imaging and R2∗ values to identify OE from OOC were 0.910 and 0.975. The AUC increased to 0.990 when combining APTw imaging and R2∗ values, yet without a significant difference to the APTw imaging or R2∗ value alone (p=0.229 and 0.082, respectively). APTw imaging values were negatively correlated with R2∗ values (r=-0.522, p<0.001).

CONCLUSION

Both APTw imaging and R2∗ values of OE are significantly different from other ovarian cystic lesions. APTw imaging combined with R2∗ values show excellent diagnostic efficacy to differentiate between OE and OOC.

[Yin Chan Quan Shu, the Obstetrics and Gynecology Monograph by Wang Kentang]

Yin Chan Quan Shu (Obstetrics and gynecology monograph) is a monograph on obstetrics and gynecology compiled by Wang Kentang in the Ming Dynasty. It had four volumes and was published in the thirtieth year of Wanli (1602) in the Ming Dynasty after it was edited by Zhang Shoukong and others. It was found that Yin Chan Quan Shu has four versions remaining. They were the version printed by Shu Lin Qiao Shan Tang in the Ming Dynasty, held in the National Library of China and the Cabinet Library of Japanese Official Documents Library; the version revised according to the version of Shu Lin Qiao Shan Tang, held in the Library of Capital Medical University, Tianjin Medical College, Shanghai Branch of the Chinese Medical Association, the Library of Guangzhou University of Chinese Medicine and the Cabinet Library of the National Archives of Japan; the version based on the version of Shu Lin Qiao Shan Tang in the Ming Dynasty, transcribed in the fourth year of Wen Hua (1807), collected in the Cabinet Library of the National Archives of Japan; the version transcribed according to the revised version in the Ming Dynasty, collected in the Shanghai Branch of the Chinese Medical Association. It was found that there was no evidence to support the existence of the so-called "version of Kangxi in the Qing Dynasty". This means almost all versions remaining came from the versions published in the Ming Dynasty. The references of Yin Chan Quan Shu came from Pulse Classic (Mai Jing), Chan Bao, Fu Ren Da Quan Liang Fang and other works with the supplement and development by Wang Kentang.Yin Chan Quan Shu was the main sources and foundation of the Criteria of Syndrome Identification and Treatment in Gynecology (Nv Ke Zheng Zhi Zhun Sheng) by Wang Kentang.

Development and multicenter validation of a novel radiomics-based model for identifying eosinophilic chronic rhinosinusitis with nasal polyps

BACKGROUND

Reliable noninvasive methods are needed to identify endotypes of chronic rhinosinusitis with nasal polyps (CRSwNP) to facilitate personalized therapy. Previous computed tomography (CT) scoring system has limited and inconsistent performance in identifying eosinophilic CRSwNP. We aimed to develop and validate a radiomics-based model to identify eosinophilic CRSwNP.

METHODS

Surgical patients with CRSwNP were recruited from Tongji Hospital and randomly divided into training (n = 232) and internal validation cohort (n = 61). Patients from two additional hospitals served as external validation cohort-1 (n = 84) and cohort-2 (n = 54), respectively. Data were collected from October 2013 to May 2021. Eosinophilic CRSwNP was determined by histological criterion. The least absolute shrinkage and selection operator and the logistic regression (LR) algorithm were used to develop a radiomics model. Univariate and multivariate LR were employed to build models based on CT scores, clinical characteristics, and the combination of radiological and clinical characteristics. Model performance was evaluated by assessing discrimination, calibration, and clinical utility.

RESULTS

The radiomics model based on 10 radiomic features achieved an area under the curve (AUC) of 0.815 in the training cohort, significantly better than the CT score model based on ethmoid-to-maxillary sinus score ratio with an AUC of 0.655. The combination of radiomic features and blood eosinophil count had a further improved performance, achieving an AUC of 0.903. The performance of these models was confirmed in all validation cohorts with satisfying predictive calibration and clinical application value.

CONCLUSIONS

A CT radiomics-based model is promising to identify eosinophilic CRSwNP. This radiomics-based method may provide novel insights in solving other clinical concerns, such as guiding personalized treatment and predicting prognosis in patients with CRSwNP.

Genetic influences of the effect of circulating inflammatory cytokines on osteoarthritis in humans

OBJECTIVE

The causal relationship between inflammatory cytokines and Osteoarthritis (OA) has not been well investigated. This study investigated the causal role of inflammatory cytokines in the risk of OA and total joint arthroplasty using the Mendelian randomization (MR) method.

METHOD

Single nucleotide polymorphisms (SNPs) robustly associated with inflammatory cytokines were used as instrumental variables. The inverse-variance weighted (IVW) method with false discovery rate (FDR) adjusted P-value (q-value) for multiple comparisons were used as the main MR method to estimate causal effects based on the summary-level data for OA (knee and hip OA, respectively) and total joint arthroplasty (TJA). Sensitivity analyses validated the robustness of the results and ensured the absence of heterogeneity and horizontal pleiotropy.

RESULTS

After FDR adjustment, macrophage colony-stimulating factor (MCSF) and vascular endothelial growth factor (VEGF) were identified as causally associated with knee OA (MCSF, odds ratio [OR]: 1.16, 95% confidence interval [CI]: 1.09-1.23, q = 5.05 × 10^-5; VEGF, OR: 1.09, 95% CI: 1.04-1.15, q = 0.011). We also observed that genetically predicted MCSF and VEGF were positively associated with the risk of TJA, and MCP3 was negatively associated with for the risk of TJA, although the effects seem fairly modest. Sensitivity analysis further excluded the influence of heterogeneity and horizontal pleiotropy.

CONCLUSIONS

Inflammatory cytokines, namely MCSF and VEGF, were causally associated with knee OA, which could enhance our understanding of inflammation in OA pathology.

A prognostic nomogram based on log odds of positive lymph nodes to predict the overall survival in biliary neuroendocrine neoplasms (NENs) patients after surgery

BACKGROUND

The prognosis of biliary neuroendocrine neoplasms (NENs) patients is affected by the status of metastatic lymph nodes. The purpose of this study was to explore the prognostic value of the log odds of positive lymph nodes (LODDS) and develop a novel nomogram to predict the overall survival (OS) in biliary NENs patients.

METHODS

A total of 125 patients with histologically confirmed biliary NENs were selected from the Surveillance, Epidemiology and End Results (SEER) database and further divided into training and validation cohorts. The discrimination and calibration of the nomogram were evaluated using the concordance index (C-index), the area under the time-dependent receiver operating characteristic curve (time-dependent AUC), and calibration plots. The net benefits and clinical utility of the nomogram were quantified and compared with those of the SEER staging system using decision curve analysis (DCA), net reclassification index (NRI), and integrated discrimination improvement (IDI). The risk stratifications of the nomogram and the SEER staging system were compared.

RESULTS

LODDS showed the highest accuracy in predicting OS for biliary NENs. The C-index (0.789 for the training cohort and 0.890 for the validation cohort) and the time-dependent AUC (> 0.7) indicated the satisfactory discriminative ability of the nomogram. The calibration plots showed a high degree of consistency. The DCA, NRI, and IDI indicated that the nomogram performed significantly better than the SEER staging system.

CONCLUSION

A novel LODDS-incorporated nomogram was developed and validated to assist clinicians in evaluating the prognosis of biliary NENs patients.

Genetic landscape of indolent and aggressive Kaposi sarcomas

BACKGROUND

Kaposi sarcoma (KS) is a rare skin tumour caused by herpesvirus 8 infection and characterized by either indolence or an aggressive course necessitating systemic therapies. The genetic basis of this difference remains unknown.

OBJECTIVES

To explore the tumour mutational burden in indolent and aggressive KS.

METHODS

We performed whole-exome sequencing on a cohort of 21 KS patients. We compared genetic landscape including tumor mutational burden between the two forms of indolent and agressive KS.

RESULTS

Aggressive KS tumours had a significantly higher TMB and a larger cumulative number of deleterious mutations than indolent KS tumours. In addition, all aggressive tumours had at least three deleterious mutations, whereas most indolent tumours harboured only one or no predicted deleterious mutations. Deleterious mutations listed in the Cancer Gene Census were detected exclusively in patients with aggressive disease. An analysis of somatic copy-number alterations (SCNA) revealed a tendency towards higher number of alterations in aggressive KS.

CONCLUSIONS

These data suggest that SCNA alterations and an increase in mutational burden promote aggressive KS and that it might be more appropriate to consider indolent KS as an opportunistic skin disease rather than a cancer.

[The versions of Shiguzhai Hui Ju Jian Bian Dan Fang by Wu Mianxue]

Shiguzhai Hui Ju Jian Bian Dan Fang, was the only medical book for prescription and formula collected and compiled by Wu Mianxue in the period of the Wanli in the Ming Dynasty (1573-1620). It had seven volumes in total with six of them popular at that time. The volumes contained 1,460 folk formula and clinical prescriptions which were divided into 111 categories based on their corresponding symptoms of diseases. The set was issued in the beginning of the 17^th century, with only three subsets of the volumes left in China today. The three remained versions were the subset of volumes 4-5 left in the Ming Dynasty in the Medical College of Tianjin, the subset of volumes 1-2 and 6-7, with preface, left in the seventeenth of the Shun Zhi Period in the Qing Dynasty (1660) in the Shanghai University of Chinese Medicine and the subset of volumes 4 and 6-7 from time unknown. Additionally, three unabridged versions were found in the Cabinet Library of the National Archives of Japan. They were the Ming version with preface of the seventeenth of the Shun Zhi Period in the Qing Dynasty and a hand-copied version left in the Edo period. It was found that the preface in the seventeenth of the Shun Zhi Period in the Qing Dynasty in both of these versions in China as well as the version in Japan, were counterfeit. The main texts in these versions were edited according to the Ming version. The hand-copied version in Japan was transcribed by Kasahara Eisan and edited by Tanba Motoken according to the Ming version in the late Edo Period.

Circadian nuclear receptor Rev-erbalpha is expressed by platelets and potentiates platelet activation and thrombus formation

Background

Adverse cardiovascular events have day/night patterns with peaks in the morning, potentially related to endogenous circadian clock control of platelet activation. Circadian nuclear receptor Rev-erbα is an essential and negative component of the circadian clock.

Purpose

We aim to investigate the expression profile and biological function of Rev-erbα in platelets.

Methods and results

Here we report the presence and functions of circadian nuclear receptor Rev-erbα in human and mouse platelets. Both human and mouse platelet Rev-erbα showed a circadian rhythm that positively correlated with platelet aggregation. Global Rev-erbα knockout and platelet-specific Rev-erbα knockout mice exhibited defective in hemostasis as assessed by prolonged tail-bleeding times. Rev-erbα deletion also reduced ferric chloride-induced carotid arterial occlusive thrombosis, prevented collagen/epinephrine-induced pulmonary thromboembolism, and protected against microvascular microthrombi obstruction and infarct expansion in an acute myocardial infarction model. In vitro thrombus formation assessed by CD41-labeled platelet fluorescence intensity was significantly reduced in Rev-erbα knockout mouse blood. Platelets from Rev-erbα knockout mice exhibited impaired agonist-induced aggregation responses, integrin αIIbβ3 activation and α-granule release. Consistently, pharmacological inhibition of Rev-erbα by specific antagonists decreased platelet activation markers in both mouse and human platelets. Mechanistically, mass spectrometry and co-immunoprecipitation analyses revealed that Rev-erbα potentiated platelet activation via oligophrenin-1-mediated RhoA/ERM (ezrin/radixin/moesin) pathway.

Conclusion

We provide the first evidence that circadian protein Rev-erbα is functionally expressed in platelets and potentiates platelet activation and thrombus formation. Rev-erbα may serve as a novel therapeutic target for managing thrombosis-based cardiovascular disease.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): This work was supported by grants from the National Science Fund for Distinguished Young Scholars (81625002), the National Natural Science Foundation of China (81930007).

p120 regulates E-cadherin expression in nasal epithelial cells in chronic rhinosinusitis

BACKGROUND

The epithelial barrier plays an important role in the regulation of immune homeostasis. The effect of the immune environment on E-cadherin has been demonstrated in previous studies. This discovery prompted new research on the targeting mechanism of E-cadherin in chronic rhinosinusitis (CRS).

METHODS

E-cadherin and p120 expression was determined by quantitative RT-PCR, and western blot. The interaction between E-cadherin and p120 was assessed by immunofluorescence staining and coimmunoprecipitation assays. Human nasal epithelial cells (HNECs) were cultured with submerged methods and transfected with p120-specific small interfering RNA. In other experiments, HNECs differentiated with the air-liquid interface (ALI) method were stimulated with various cytokines and Toll-like receptor (TLR) agonists. The barrier properties of differentiated HNECs were determined by assessing fluorescent dextran permeability.

RESULTS

E-cadherin and p120 expression was decreased in HNECs from patients with CRS, and the p120 protein expression level was positively correlated with that of E-cadherin. Two isoforms of p120 (p120-1 and p120-3) were expressed in HNECs, with p120-3 being the main isoform. Knocking down p120 in HNECs cultured under submerged conditions significantly reduced the E-cadherin protein expression. The Rac1 inhibitor NSC23766 reversed the protein expression of E-cadherin in p120 knockdown experiments. Inflammatory mediators, including IL-4, TNF-α, TGF- β, LPS and IFN-Î, reduced E-cadherin and p120 protein expression and increased paracellular permeability. Dexamethasone abolished the downregulation of E-cadherin and p120 caused by inflammatory mediators.

CONCLUSIONS

p120 is involved in regulating E-cadherin protein expression in CRS. Dexamethasone may alleviate the reduction in E-cadherin and p120 protein expression caused by inflammatory mediators.

Biopsy-tract haemocoagulase injection reduces major complications after CT-guided percutaneous transthoracic lung biopsy

AIM

To determine whether the injection of haemocoagulase into the biopsy tract can reduce pneumothorax and pulmonary haemorrhage after computed tomography (CT)-guided percutaneous transthoracic lung biopsy (PTLB).

MATERIALS AND METHODS

A retrospective study was performed involving patients with undiagnosed pulmonary lesions scheduled for PTLB between January 2020 and March 2021. Patients were assigned to the haemocoagulase group or the non-haemocoagulase group. After CT-guided biopsies were performed with a 17 G coaxial system, patients in the haemocoagulase group received a haemocoagulase injection (0.2-0.5 units) in the biopsy tract as the sheath was withdrawn. Postoperative image studies were performed to evaluate complications, including pneumothorax and pulmonary haemorrhage. Factors, including the patient's position, lesion location, and pathological results, were evaluated to determine their associations with the complications.

RESULTS

A total of 100 patients were included, with 44 men and a mean age of 53 years old. The overall incidences of pneumothorax and pulmonary haemorrhage were 15% and 13%, respectively. The incidences of pneumothorax and pulmonary haemorrhage were statistically significantly lower in the haemocoagulase group (8% and 6%, respectively) than in the non-haemocoagulase group (22% and 20%, respectively; p=0.04 and 0.03, respectively). There was no statistically significant difference in haemoptysis between the haemocoagulase (6%) and non-haemocoagulase (2%) groups (p=0.23). There were also no statistically significant associations of pneumothorax or pulmonary haemorrhage with the patients' positions, lesion location, or pathological results.

CONCLUSION

Biopsy tract haemocoagulase injection reduced the incidences of postoperative pneumothorax and pulmonary haemorrhage after PTLB.

Intravoxel incoherent motion diffusion-weighted imaging as a quantitative tool for evaluating disease activity in patients with axial spondyloarthritis

AIM

To determine the correlations between four quantitative magnetic resonance imaging (MRI) parameters derived from intravoxel incoherent motion diffusion-weighted images (IVIM DWI) and the semi-quantitative Spondyloarthritis Research Consortium of Canada (SPARCC) score of the sacroiliac joint (SIJ) and five clinical activity indices in patients with axial spondyloarthritis (axSpA).

AND METHODS

A total of 75 patients with axSpA and complete clinical activity indices and SIJ MRI were enrolled to this prospective study. Univariable and multivariable linear regression analyses were performed to evaluate correlations between MRI parameters and clinical activity indices after controlling for confounders. All data were further analysed using Pearson's correlation coefficients (r).

RESULTS

Only pure diffusion coefficient (D) and incoherent perfusion related microcirculation (D∗) were found to be independently positively correlated with several clinical activity indices (all p<0.05). Positive correlations were observed between D and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI), Patient Global Assessment (PGA), extent of influence of pain, with r of 0.605, 0.402, 0.319, and 0.485 (all p<0.0125). D∗ correlated positively with BASDAI, BASFI, and PGA (r=0.436, 0.356, 0.301, respectively; all p<0.0125).

CONCLUSION

D and D∗ derived from IVIM DWI could be associated with some disease activity indices in patients with axSpA; apparent diffusion coefficient (ADC) and SPARCC scores were not correlated with these indices. IVIM DWI may be a useful tool for the quantitative assessment of disease activity in patients with axSpA.

[Current status and prospect of virtual reality technique's application in wound repair]

As a new technology of drug-free treatment, virtual reality technique has been used in various medical fields, and is being increasingly applied in the field of wound repair. Virtual reality technology can alleviate the pain caused by acute and chronic wounds, relieve the psychological anxiety of patients with wounds, and then facilitate the recovery of patients. This paper reviews the research progress of virtual reality technique's application as a clinical adjuvant therapy in wound repair in three aspects: pain treatment, psychological treatment, and functional rehabilitation, analyzes the advantages and disadvantages of this technique, and discusses the prospects of its further application in the field of wound repair.

[Identification of serological biomarkers for diagnosis of rheumatoid arthritis using a protein array-based approach]

OBJECTIVE

To study the cytokine patterns in patients with rheumatoid arthritis (RA) and healthy individuals and identify candidate serum biomarkers for clinical diagnosis of RA.

METHODS

This study was conducted among 59 patients diagnosed with RA in our hospital from 2015 to 2019 with 46 age- and gender-matched healthy subjects who received regular physical examinations in our hospital as the control group. Serological autoimmune profiles of 5 RA patients and 5 healthy control subjects were obtained from human cytokine microarrays. We selected 4 differentially expressed cytokines (LIMPII, ROBO3, Periostin and IGFBP-4) and 2 soluble cytokine receptors of interest (2B4 and Tie-2) and examined their serum levels using enzyme-linked immunosorbent assay in 54 RA patients and 41 healthy control subjects. Spearman correlation test was performed to assess the correlation of serum cytokine and soluble receptor expression levels with the clinical features including rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), disease activity score (DAS28) and health assessment questionnaire (HAQ). Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic capability of these cytokines.

RESULTS

We identified 6 dysregulated cytokines and soluble receptors (2B4, LIMPII, Tie-2, ROBO3, periostin and IGFBP-4) in RA patients (P < 0.01). The serum levels of LIMPII, ROBO3 and periostin were significantly correlated with the disease activity indicators including RF (P < 0.001), CRP (P < 0.001), DAS28 (P < 0.001) and HAQ (P < 0.001) in RA patients. Among the 6 candidate cytokines, 2B4 showed the largest area under the curve (AUC) of 0.861 for RA diagnosis (P < 0.001), followed then by LIMPII, ROBO3, periostin, Tie-2 and IGFBP-4.

CONCLUSION

Serum levels of LIMPII, ROBO3 and periostin can be indicative of the disease activity of RA, and serum 2B4, LIMPII, periostin, ROBO3, IGFBP-4 and Tie-2 levels may serve as biomarkers for the diagnosis of RA.

[Transoral robotic surgery for treatment of lingual thyroglossal duct cyst]

Objective: To investigate the feasibility, safety and efficacy of transoral robotic surgery (TORS) in the treatment of lingual thyroglossal duct cyst (LTGDC). Methods: The clinical data of 10 patients with LTGDC treated with TORS in Tongji Hospital affiliated to Tongji Medical College of Huazhong University of Science and Technology from May 2017 to November 2020 were analyzed retrospectively,including 6 males and 4 females, aged 5-44 years. The cysts were fully exposed, and resection usually started from the cephalic side of lesions. The range of resection was 3 to 5 mm away from the lesions, and partial hyoid bone was removed if necessary. Intra-operative robotic set-up time,operation time and estimated blood loss,and post-operative local bleeding, dyspnea and recovery time for oral intake were analyzed. SPSS 12.0 software was used for statistical analysis. Results: The cysts in all 10 patients were successfully resected by TORS with da Vinci Si surgical system. The mean robotic set-up and exposure time, operation time, estimated intraoperative blood loss and recovery time for oral intake were (15.5±7.1) min, (17.6±7.4) min, (8.9±6.4)ml and (2.3±2.2)days, respectively. No patient required tracheostomy intra-or post-operatively, and no symptoms of airway obstruction, postoperative bleeding, pharyngeal fistula, hoarseness and neurological impairment occurred after operation. The patients were followed up for 5 to 47 months, with median follow-up time of 17 months, and no recurrence was observed. Conclusion: TORS is safe and feasible for resection of LTGDC, with rapid recovery and low recurrence rate.

Elastic criterion for shear-banding instability in amorphous solids

In amorphous solids, plastic flow is prone to localization into shear bands via an avalanche of shear-transformation (ST) rearrangements of constituent atoms or particles. However, such banding instability still remains a lack of direct experimental evidence. Using a real 3D colloidal glass under shear as proof of principle, we study STs' avalanches into shear banding that is controlled by strain rates. We demonstrate that, accompanying the emergent shear banding, the elastic response fields of the system, typical of a quadrupole for shear and a centrosymmetry for dilatation, lose the Eshelby-type spatial symmetry; instead, a strong correlation appears preferentially along the banding direction. By quantifying the fields' spatial decay, we identify an elastic criterion for the shear-banding instability, that is, the strongly correlated length of dilatation is smaller than the full length of shear correlation. Specifically, ST-induced free volume has to be confined within the elastic shear domain of ST so that those STs can self-organize to trigger shear banding. This physical picture is directly visualized by tracing the real-space evolution of local dilatation and ST particles. The present work unites the two classical mechanisms: free volume and STs, for the fundamental understanding of shear banding in amorphous solids.

Joint Determination of Reactor Antineutrino Spectra from ^{235}U and ^{239}Pu Fission by Daya Bay and PROSPECT

A joint determination of the reactor antineutrino spectra resulting from the fission of ^{235}U and ^{239}Pu has been carried out by the Daya Bay and PROSPECT Collaborations. This Letter reports the level of consistency of ^{235}U spectrum measurements from the two experiments and presents new results from a joint analysis of both data sets. The measurements are found to be consistent. The combined analysis reduces the degeneracy between the dominant ^{235}U and ^{239}Pu isotopes and improves the uncertainty of the ^{235}U spectral shape to about 3%. The ^{235}U and ^{239}Pu antineutrino energy spectra are unfolded from the jointly deconvolved reactor spectra using the Wiener-SVD unfolding method, providing a data-based reference for other reactor antineutrino experiments and other applications. This is the first measurement of the ^{235}U and ^{239}Pu spectra based on the combination of experiments at low- and highly enriched uranium reactors.

Joint Measurement of the ^{235}U Antineutrino Spectrum by PROSPECT and STEREO

The PROSPECT and STEREO collaborations present a combined measurement of the pure ^{235}U antineutrino spectrum, without site specific corrections or detector-dependent effects. The spectral measurements of the two highest precision experiments at research reactors are found to be compatible with χ^{2}/ndf=24.1/21, allowing a joint unfolding of the prompt energy measurements into antineutrino energy. This ν[over ¯]_{e} energy spectrum is provided to the community, and an excess of events relative to the Huber model is found in the 5-6 MeV region. When a Gaussian bump is fitted to the excess, the data-model χ^{2} value is improved, corresponding to a 2.4σ significance.