[New progress on diagnosis and treatment for indeterminate-phase chronic hepatitis B virus-infected patients]

Authoritative guidelines at home and abroad typically classify chronic hepatitis B virus (HBV) infection into four stages. However, in clinical practice, a considerable number of patients do not meet the guidelines for staging and are called "indeterminate phase" chronic HBV- infected patients. Studies have shown that patients in the indeterminate phase account for about 30%-50% of chronic HBV infection, have significant liver histological changes or even cirrhosis in a large proportion, and are at a higher risk of HCC and death if they do not receive antiviral therapy. Preliminary research shows that patients in the indeterminate phase who receive antiviral treatment have a good virological response and a remarkable reduced HCC risk. To this end, the 2022 publication "Expert Opinions on Expanding Antiviral Treatment for Chronic Hepatitis B" recommends aggressive treatment for patients with an indeterminate phase who have undergone more than a year of follow-up. However, there is still a lack of unified standards to refine the classification, as well as a lack of effective and rapid non-invasive diagnostic methods to identify patients in the indeterminate phase who are at risk for disease progression. This article aims to review the researches on the proportion, clinical characteristics, disease progression, and treatment benefits to further explore how to better manage indeterminate-phase chronic HBV-infected patients.

[Construction of natural population cohort on telephone follow-up management quality control system and discussion regarding critical issues by REDCap system]

With completing a baseline survey of a large natural population cohort, conducting regular follow-up has become a key factor in further improving the quality of cohort construction and ensuring its sustainable development. Typical cohort follow-up methods include repeat surveys, routine monitoring, and community-oriented surveillance. However, in practical applications, there are often issues such as high costs, difficulty, and high error rates. Telephone follow-up is an important supplementary method to the methods mentioned above, as it has the characteristics of low cost, fast response, and high quality. However, the with difficult organization, quality control is challenging, response rates are low, and management levels vary widely, which limits its widespread use in large-scale population cohort studies. Given the above problems, this study draws on customer relationship management based on the actual needs of the China Northwest Cohort follow-up. It relies on the REDCap electronic data collection platform to build a telephone follow-up management and quality control system. Targeted solutions are provided for key issues in telephone follow-up implementation, including organizational structure, project management, data collection, and process quality control, to improve the quality control level of telephone follow-up comprehensively and thereby enhance the quality and efficiency of follow-up. We hope to provide standardized follow-up programs and efficient quality control tools for newly established and existing cohort studies.

Natural phytoalexins inspired the discovery of new biphenyls as potent antifungal agents for treatment of invasive fungal infections

With the aim of discovering novel and effective antifungal agents derived from natural sources, a series of new biphenyls based on natural biphenyl phytoalexins were designed, synthesized and evaluated for their antifungal activities against four invasive fungi. By modifying the two benzene rings of noraucuparin, a well-known biphenyl phytoantitoxin, some promising compounds with remarkable antifungal activity were discovered. Notably, compounds 23a, 23e and 23h exhibited potent activities and a broad antifungal spectrum with low MICs of 0.25-16 μg/mL, which were 8-256-fold more potent than that of the lead compound noraucuparin. Particularly, they displayed comparable potency to the positive control amphotericin B against Cryptococcus neoformans. Some interesting structure-activity relationships have also been discussed. Preliminary mechanism studies revealed that compound 23h might achieve its rapid fungicidal activity by disrupting the fungal cell membrane. Moreover, compound 23h exhibited significant inhibition against some virulence factors of Cryptococcus neoformans, low toxicity to normal human cells, as well as favorable pharmacokinetic and drug-like properties. The above results evidenced that the development of new antifungal candidates derived from natural phytoalexins was a bright and promising strategy.

Improved Measurement of the Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Reactor neutrino experiments play a crucial role in advancing our knowledge of neutrinos. In this Letter, the evolution of the flux and spectrum as a function of the reactor isotopic content is reported in terms of the inverse-beta-decay yield at Daya Bay with 1958 days of data and improved systematic uncertainties. These measurements are compared with two signature model predictions: the Huber-Mueller model based on the conversion method and the SM2018 model based on the summation method. The measured average flux and spectrum, as well as the flux evolution with the ^{239}Pu isotopic fraction, are inconsistent with the predictions of the Huber-Mueller model. In contrast, the SM2018 model is shown to agree with the average flux and its evolution but fails to describe the energy spectrum. Altering the predicted inverse-beta-decay spectrum from ^{239}Pu fission does not improve the agreement with the measurement for either model. The models can be brought into better agreement with the measurements if either the predicted spectrum due to ^{235}U fission is changed or the predicted ^{235}U, ^{238}U, ^{239}Pu, and ^{241}Pu spectra are changed in equal measure.

Precision Measurement of Reactor Antineutrino Oscillation at Kilometer-Scale Baselines by Daya Bay

We present a new determination of the smallest neutrino mixing angle θ_{13} and the mass-squared difference Δm_{32}^{2} using a final sample of 5.55×10^{6} inverse beta-decay (IBD) candidates with the final-state neutron captured on gadolinium. This sample is selected from the complete dataset obtained by the Daya Bay reactor neutrino experiment in 3158 days of operation. Compared to the previous Daya Bay results, selection of IBD candidates has been optimized, energy calibration refined, and treatment of backgrounds further improved. The resulting oscillation parameters are sin^{2}2θ_{13}=0.0851±0.0024, Δm_{32}^{2}=(2.466±0.060)×10^{-3}  eV^{2} for the normal mass ordering or Δm_{32}^{2}=-(2.571±0.060)×10^{-3}  eV^{2} for the inverted mass ordering.

[Application of isotemporal substitution model in epidemiological research]

Isotemporal substitution model is a powerful tool to explore the real association between physical behavior and health outcomes, which has the potential of the application in large-scale cohort study. This paper systematically introduces the principle of isotemporal substitution model and its implementation method in specific analysis to provide analytical ideas for the epidemiological research related to physical behavior in China. The baseline data of Regional Ethic Cohort Study in Northwest China conducted in Shaanxi province were used to analyze the relationship between physical behavior and cardiovascular disease with single-factor model, partition model and isotemporal substitution model. The advantages and disadvantages of different models were compared, and the advantages of isotemporal substitution model in quantifying physical activity health risk were introduced. Isotemporal substitution model could qualify physical behavior and health outcomes, which has wide application value in epidemiological research.

First Measurement of High-Energy Reactor Antineutrinos at Daya Bay

This Letter reports the first measurement of high-energy reactor antineutrinos at Daya Bay, with nearly 9000 inverse beta decay candidates in the prompt energy region of 8-12 MeV observed over 1958 days of data collection. A multivariate analysis is used to separate 2500 signal events from background statistically. The hypothesis of no reactor antineutrinos with neutrino energy above 10 MeV is rejected with a significance of 6.2 standard deviations. A 29% antineutrino flux deficit in the prompt energy region of 8-11 MeV is observed compared to a recent model prediction. We provide the unfolded antineutrino spectrum above 7 MeV as a data-based reference for other experiments. This result provides the first direct observation of the production of antineutrinos from several high-Q_{β} isotopes in commercial reactors.

[Effect of underdilated stent on the occurrence of hepatic encephalopathy after transjugular intrahepatic portosystemic shunt creation]

Objective: To evaluate whether underdilated stent could reduce the occurrence of hepatic encephalopathy (HE) after transjugular intrahepatic portosystemic shunt (TIPS) creation. Methods: A total of 197 patients with decompensated liver cirrhosis, who had underwent TIPS creation at Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, were analyzed retrospectively, including 110 males and 87 females with age 25-79 (54±11) years old. Uncovered and covered stents with 8 mm diameter were implanted in all subjects, and then dilated by balloon catheters with 6 mm or 8 mm diameter. The patients were divided into two groups, including underdilated group (6 mm, n=105) and control group (8 mm, n=92).Kaplan-Meier curves were used to illustrate cumulative rate of HE, and the differences were assessed with the log-rank test. Multivariate analyses with a Cox regression model were conducted to explore the risk factors for HE. Results: During a median follow-up period of 29 (12-54) months, 16 (15.2%) patients developed HE in the underdilated group and 27 (29.3%) patients in the control group. There was a significant difference in the cumulative rate of HE (P=0.014), but no statistical differences were found in terms of variceal rebleeding, shunt dysfunction and survival between the two groups (P=0.608, P=0.659, P=0.968). In multivariated analysis, group assignment (underdilated vs. control, HR=0.291, 95%CI 0.125-0.674, P=0.004) was identified as an independent risk factor for HE after TIPS creation. Conclusion: Underdilated TIPS could reduced the risk of HE compared with completely dilated TIPS, with comparable risk of variceal rebleeding, shunt dysfunction and mortality. And it is worthy of applying this technique to a large sample of patients in clinical practice.

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.

[Comparison of hip offset and rotation center reconstruction between robot-assisted and manual total hip arthroplasty]

Objective: To compare the differences of hip offset and rotation center reconstruction between robot-assisted and manual total hip arthroplasty (THA). Methods: Patients underwent robot-assisted and manual THA from May to September of 2020 in the First Affiliated Hospital of Chongqing Medical University were enrolled in this study. The patients included 27 patients (28 hips) in robot-assisted THA (rTHA) group and 29 patients (31 hips) in manual THA (mTHA) group. In rTHA group, there were 16 males and 11 females, with a mean age of (59±13) years. In mTHA group, there were 18 males and 11 females, with a mean age of (63±14) years. Basic information, including gender, age, body mass index (BMI), diagnosis and functional scoring etc, were recorded. In rTHA group, Mako robot system was used for preoperative planning, intraoperative real-time location and navigation. In mTHA group, traditional preoperative template design and surgical procedure were carried out. Operation time and functional scoring were compared postoperatively. Femoral offset, acetabular offset, global offset, rotation center changes in vertical and horizontal directions were measured on pelvis X-ray and analyzed. The correlation between intraoperative feedback of global offset change in robot system and postoperative measured global offset were analyzed. Results: Operation time in rTHA group was (80±10) min, which was statistically longer than that in mTHA group ((58±18) min, P<0.001). With 6 months' follow-up, the Harris scoring in rTHA group was 94.9±2.8, which was statistically higher than that in mTHA group (93.1±2.8, P=0.017), however there was no statistic difference in WOMAC scoring between rTHA and mTHA group (7.0±3.8 vs 7.1±2.4, P=0.840). Absolute global offset change within 5 mm, 5-10 mm and lager than 10 mm were 71.4%(20/28), 28.6%(8/28) and 0 in rTHA group, which were 45.2%(14/31), 29.0%(9/31) and 25.8%(8/31) in mTHA group (all P<0.05). A positive relation was found between intraoperative feedback of global offset change in robot system and postoperative measured global offset in rTHA group (r=0.77, P<0.001). It was found that rotation center changes concentrated in outer upper quadrant in both groups, and rotation center change in rTHA group concentrated mainly in the area less than 10 mm, however, rotation center change in mTHA group was more dispersive compared with rTHA group. Conclusion: rTHA may accurately reconstruct hip offset and rotation center, intraoperation feedback of global offset change may be an effective reference.

Life during the pandemic: an international photo-elicitation study with medical students

BACKGROUND

The SARS-CoV-2 (COVID-19) pandemic is a global event with unprecedented impact on individuals and communities around the world. The purpose of this study is to use a modified photo-elicitation methodology to examine the impact of the COVID-19 pandemic on the lives of medical students and their communities around the world.

METHODS

Participating medical students were asked to take photographs for 14 days. In lieu of an interview, which is customary for photo-elicitation projects, participants were asked to share a reflection (a paragraph or two) for each photograph they contributed to the study.

RESULTS

Between April 27th, 2020 and May 11th, 2020 26 students from 19 medical schools across 13 countries shared photographs and reflections. Qualitative analysis of written reflections revealed that medical students felt the impact of the pandemic on several levels 1) individual, 2) interpersonal, 3) educational, and 4) societal.

CONCLUSIONS

The COVID-19 pandemic has impacted the lives of medical students on multiple levels. As individuals, students felt emotional distress but found resilience through physical activity and the establishment of new routines. Many students felt isolated as their interpersonal relationships were confined due to social distancing measures. These feelings could be combated with new educational initiatives focused on group collaboration. Lastly, students reflecting on the larger societal implications were concerned with the economic ramifications of the virus and its impact on their future. This study brought together students from several different countries to engage in an applied learning program as a model for equitable global health research.

[Treatment outcome of 100 patients with hepatoblastoma based on a new risk stratification]

Objective: To provide the risk stratification method of hepatoblastoma (HB) suitable for implementation in China and explore the new treatment method for high-risk HB patients. Methods: A total of 100 cases of children and adolescents under 18 years old with newly diagnosed HB in Sun Yat-sen University Cancer Center and Sun Yat-sen University First Affiliated Hospital from September 2014 to September 2018 were included. According to the clinical stage, AFP level, pathological subtype and other factors, patients were stratified into four groups: extremely low-, low-, intermediate- and high-risk. The patients at very low risk were treated with surgery only and followed-up. The patients at very low risk were treated with C5V(Cisplatin+ 5-Fluroracil+ Vincristine) regimen for 4 courses. The patients at intermediate risk were treated with C5VD(Cisplatin+ 5-Fluroracil+ Vincristine+ Doxorubicin)regimen before and after surgery for 6-8 courses. The patients at high risk were treated with C5VD and IIV (ifoshamide+ irinotecan+ vincristine) alternately before and after surgery for 8 courses. Results: One hundred patients were stratified into extremely low-risk, low-risk, medium-risk and high-risk groups for 2, 10, 51 and 37 cases, respectively. Eighty three cases had evaluable lesions before chemotherapy. Among them, 65 patients achieved partial remission, stable disease and progressive disease were observed in 10, and 8 cases, respectively, with a response rate of 78.3%. During a median follow-up of 20 months, 30 patients experienced tumor relapse or progression, and 27 of them died. The 2-years progression-free survival (PFS) and overall survival (OS) rates were 69.2% and 72.0%, respectively. The 2-years PFS rates of patients with extremely low risk, low risk, medium risk and high risk were 100%, 88.9%, 75.3% and 43.2%, respectively. The 2-years OS rates were 100%, 100%, 81.0% and 44.8%, respectively. Conclusions: The novel HB risk classification is simple and feasible. With active comprehensive treatment, patients at extremely low-, low- and medium-risk have excellent outcomes. The survival rate of high-risk HB patients remains to be improved, and new treatment strategies need to be explored.

[Safety evaluation of mass inoculation of 23 valent pneumococcal polysaccharide vaccine among elderly people aged 60 and above in Shanghai from 2013 to 2017]

Objective: To evaluate the safety of 23 Valent Pneumococcal Polysaccharide Vaccine (PPV23) among eldly people aged 60 and above in Shanghai. Methods: A total of 1 310 660 monitoring data of adverse events following immunization (AEFI) of PPV23 among people aged 60 and above were collected through the National AEFI Surveillance System from September 14, 2013 to December 31, 2017 in Shanghai. And the descriptive epidemiological methods were used for analysis. Results: 433 cases of AEFI were reported from September 14, 2013 to December 31, 2017, with the incidence rate of AEFI was 33.04/100 000 doses. The general reactions were reported as 392 cases (90.53%), with 17 cases of abnormal reactions (3.93%), 23 cases of coincidences (5.31%) and 1 case of psychogenic reactions (0.23%). The reported incidence rates of general reactions and abnormal reactions of free PPV23 inoculation among elderly people in urban areas were 41.31 per 100 000 doses and 1.91/100 000 doses, respectively, which were higher than those in suburban areas (24.18/100 000 doses, 1.32/100 000 doses) and exurban areas (27.84/100 000 doses, 0.59/100 000 doses). The reported incidence rate of general reaction in females (35.38/100 000 doses) was higher than that in males (24.06/100 000 doses), and the reported incidence rate of abnormal reaction in males (1.58/100 000 doses) was higher than that in females (1.03/100 000 doses). The reported incidence rates of general and abnormal reactions were the highest in 60-64 years old group (62.65/100 000 doses and 4.87/100 000 doses, respectively). In addition, all patients with general reactions or abnormal reactions were better or cured. Conclusion: PPV23 vaccination is safe among people aged 60 and above in Shanghai.

Improved Constraints on Sterile Neutrino Mixing from Disappearance Searches in the MINOS, MINOS+, Daya Bay, and Bugey-3 Experiments

Searches for electron antineutrino, muon neutrino, and muon antineutrino disappearance driven by sterile neutrino mixing have been carried out by the Daya Bay and MINOS+ collaborations. This Letter presents the combined results of these searches, along with exclusion results from the Bugey-3 reactor experiment, framed in a minimally extended four-neutrino scenario. Significantly improved constraints on the θ_{μe} mixing angle are derived that constitute the most constraining limits to date over five orders of magnitude in the mass-squared splitting Δm_{41}^{2}, excluding the 90% C.L. sterile-neutrino parameter space allowed by the LSND and MiniBooNE observations at 90% CL_{s} for Δm_{41}^{2}<13  eV^{2}. Furthermore, the LSND and MiniBooNE 99% C.L. allowed regions are excluded at 99% CL_{s} for Δm_{41}^{2}<1.6 eV^{2}.

Constraining the External Capture to the ^{16}O Ground State and the E2 S Factor of the ^{12}C(α,γ)^{16}O Reaction

The ^{12}C(α,γ)^{16}O reaction is one of the most crucial reactions in nuclear astrophysics. The E2 external capture to the ^{16}O ground state (GS) has not been emphasized in previous analyses but may make a significant contribution to the ^{12}C(α,γ)^{16}O cross section depending on the value of the GS asymptotic normalization coefficient (ANC). In the present work, we determine this ANC to be 337±45  fm^{-1/2} through the ^{12}C(^{11}B,^{7}Li)^{16}O reaction using a high-precision magnetic spectrograph. This sheds light on the existing large discrepancy of more than 2 orders of magnitude between the previously reported ANC values. Based on the new ANC, we experimentally constrain the GS external capture and show that through interference with the high energy tail of the 2^{+} subthreshold state, a substantial enhancement in the GS S_{E2}(300) factor can be obtained (70±7  keV b) compared to that of a recent review (45 keV b), resulting in an increase of the total S factor from 140 to 162 keV b, which is now in good agreement with the value obtained by reproducing supernova nucleosynthesis calculations with the solar-system abundances. This work emphasizes that the external capture contribution for the ground state transition cannot be neglected in future analyses of the ^{12}C(α,γ)^{16}O reaction.

[The clinical efficacy of arthroscopic combined with dual-plane high tibial osteotomy in the treatment of anterior cruciate ligament injury combined with varus deformity of knee joint]

Objective: To explore the short-term effectiveness of arthroscopic combined with dual-plane high tibial osteotomy in the treatment of anterior cruciate ligament injury combined with varus deformity of knee joint. Methods: A retrospective study was performed on 17 patients with anterior cruciate ligament injury combined with varus deformity of knee joint who underwent arthroscopic combined with dual-plane high tibial osteotomy at Department of Bone and Joint, the Affiliated Hospital of Southwest Medical University from January 2017 to June 2018.There were 11 males (11 knees) and 6 females (6 knees), aged 41.3 years (range: 32 to 49 years) .During the surgery, the weight bearing line of lower extremity was set to 62.5% position of the tibial plateau on coronal plane. The tibial slope was adjusted to the normal range on sagittal plane, and anterior cruciate ligament was reconstructed to improve the stability of knee joint.At final follow up, full length weight bearing X ray was used to evaluate the position of weight bearing line, femoral tibial angle and tibial slope pre- and post-operatively.The Lysholm scores, Hospital for Special Surgery score, Tegner knee activity scores and International Knee Documentation Committee (IKDC) scores were used to estimate knee joint function, while the Lachman test, KT-1000 side-to-side difference and pivot-shift test were used to estimate the knee joint stability. Results: The patients were followed up for 1.8 years(range:1.2 to 2.5 years). No complication such as infection, deep vein thrombosis, graft failure, nonunion or delayed union was observed.The weight bearing line was corrected from (28.48±2.24)% preoperatively to (57.43±1.02)% postoperatively (t=46.80, P=0.00) .The femoral tibial angle was improved from (172.31±3.37) ° preoperatively to (178.91±1.34) ° postoperatively(t=10.46, P=0.00). The tibial slope was decreased from (14.29±1.26) ° preoperatively to (9.31±0.79) ° postoperatively (t=24.59, P=0.00) . The KT-1000 side-to-side difference decreased from (7.95±1.19) mm preoperatively to (1.79±0.49)mm postoperatively(t=18.34, P=0.00). At the last follow-up, Lysholm score, Hospital for Special Surgery score, Tegner score, and the IKDC knee evaluation score of patients showed significant improvement from preoperative(P<0.05). Conclusion: Arthroscopic combined with dual-plane high tibial osteotomy can get a good short term efficacy in the treatment of anterior cruciate ligament injury combined with varus deformity of knee joint which can significantly improve the alignment of lower extremity and knee joint stability.

Extraction of the ^{235}U and ^{239}Pu Antineutrino Spectra at Daya Bay

This Letter reports the first extraction of individual antineutrino spectra from ^{235}U and ^{239}Pu fission and an improved measurement of the prompt energy spectrum of reactor antineutrinos at Daya Bay. The analysis uses 3.5×10^{6} inverse beta-decay candidates in four near antineutrino detectors in 1958 days. The individual antineutrino spectra of the two dominant isotopes, ^{235}U and ^{239}Pu, are extracted using the evolution of the prompt spectrum as a function of the isotope fission fractions. In the energy window of 4-6 MeV, a 7% (9%) excess of events is observed for the ^{235}U (^{239}Pu) spectrum compared with the normalized Huber-Mueller model prediction. The significance of discrepancy is 4.0σ for ^{235}U spectral shape compared with the Huber-Mueller model prediction. The shape of the measured inverse beta-decay prompt energy spectrum disagrees with the prediction of the Huber-Mueller model at 5.3σ. In the energy range of 4-6 MeV, a maximal local discrepancy of 6.3σ is observed.

[Functional and supraomohyoid neck dissection in stage cN0/N1 oral squamous cell carcinoma]

Objective: To evaluate the clinical effects of functional neck dissection (FND) and supraomohyoid neck dissection (SOND) in patients with cN0/N1 oral squamous cell carcinoma (OSCC). Methods: A total of 210 patients with stage cN0/N1 OSCC underwent FND and SOND between January 2012 and May 2015 were retrospectively reviewed, among which, 147 patients were male and 63 were female, with an age range of 23-82 years and mean age of (62.2±10.2) years. There were 112 and 98 patients in FND and SOND groups, respectively. The follow-up data included cervical lymph node metastasis, movement of shoulder joint, great auricular nerve function, recurrence rate of cervical lymph nodes. Results: There was no significant difference in gender, age, tumor location, T stage, N stage, histological grades between the two groups (all P>0.05). Compared to patients in FND group, the activities of shoulder joint and earlobe numbness improved significantly in SOND group. Of the 210 patients, 17 patients (8.1%) had cervical recurrence, with 9 patients (8.0%) in FND group and 8 patients (8.2%) in SOND group. No significant difference was observed for neck recurrence between the two groups (P=0.973). Conclusion: SOND can be safely performed in cN0 or cN1 OSCC patients, which avoids major complications of FND, and improves postoperative quality of life in those patients.

Synthesis of high quality silver nanowires and their applications in ultrafast photonics

Silver nanowires are widely used in catalysts, surface enhanced Raman scattering, microelectronic equipment, thin film solar cells, microelectrodes and biosensors for their excellent conductivity, heat transfer, low surface resistance, high transparency and good biocompatibility. However, the optical nonlinearity of silver nanowires has not been further explored yet. In this paper, three silver nanowire samples with different concentrations are produced via a typical hydrothermal method. Their applications to fiber lasers are implemented to prove the optical nonlinearity of silver nanowires for the first time. Based on three kinds of silver nanowires, the mode-locked operation of fiber lasers is successfully realized. Moreover, the fiber laser based on the silver nanowire with a concentration of 2 mg/L demonstrates the shortest pulse duration of 149.3 fs. The experiment not only proves the optical nonlinearity of silver nanowires, but also has some enlightenment on the selection of the optimum concentration of silver nanowires in the consideration of ultrashort pulse output.

[Observation on safety of sequential vaccination schedule of different strain inactivated poliovirus vaccines]

Objective: To evaluate the safety of population based sequential vaccination schedule of inactivated poliovirus vaccines prepared with different strains. Methods: This randomized, parallel-group controlled trial was conducted from March, 2017 to May, 2018, in Shanghai. Adverse reaction data of Sabin strain inactivated polio vaccine (sIPV), wild strains inactivated polio vaccines (wIPV) and bivalent types Ⅰ and Ⅲ oral poliomyelitis vaccine (bOPV) were systematically collected through active observation in 1 917 infants in Shanghai after the vaccination at 2, 3, 4 months old. The eligible infants aged 2 months were divided into 4 groups: ①sIPV+sIPV+bOPV group; ②sIPV+wIPV+bOPV group; ③wIPV+sIPV+bOPV group; ④wIPV+wIPV+bOPV group. Results: The incidence of adverse reaction 30 days later after 3 basic dose vaccinations was 16.79% (946/5 633). No serious adverse reaction was reported. Local and systemic reactions were mainly mild. Common local reactions were pain, erythema, cutaneous nodule, etc.; and common systemic reactions were abnormal crying, drowsiness, diarrhea and appetite lost, etc.. The incidence of local reactions 30 days later after 3 basic dose vaccinations was 1.65% (93/5 633), and the incidence rates of grade 1-3 reactions were1.26% (71/5 633), 0.21% (12/5 633) and 0.20% (11/5 633) respectively. The incidence rate of systemic reactions 30 days later after 3 basic vaccinations was 15.14% (853/5 633), and the incidence rates of grade 1-3 reactions were 11.33% (638/5 633), 3.18% (179/5 633) and 0.64% (36/5 633) respectively. There were no significant differences in the rate of grade 3 reaction among different groups (χ(2)=4.17, P=0.24). Conclusions: No severe adverse reactions related to sequential vaccination of different strain inactivated polio vaccines were observed, most of reactions were mild and all of them were cured. It is safe to use sIPV and wIPV simultaneously or alternately for childhood sequential vaccination.

Fluoride at waste oyster shell surfaces - Role of magnesium

Reaction of fluoride with waste oyster shell was studied. To enhance the stability and adsorption capacity, oyster shell was coated with Al(OH)₃ and the adsorption behaviors were compared with the uncoated one. When at low fluoride concentration (<30 mg/L), fluoride removal efficiency decreased with increasing pH, and the adsorption could be modeled by Langmuir isotherm. At high fluoride concentration (>100 mg/L), linear adsorption isotherm fitted better, in which the adsorption capacity of fluoride increased linearly with increasing equilibrium fluoride concentration. The coated oyster shell showed higher adsorption capacity and wider workable pH range. From XPS analysis, the presence of CaF₂ was confirmed by the peak at 684.7 eV when fluoride concentration increased. It was noted that magnesium content of waste oyster shell reacted with fluoride to form significant fractions of MgF₂ whose corresponding peak was detected at 685.6-685.8 eV. For coated oyster shell, fluoride reacted with Ca, Mg, and Al. The reaction mechanism was mainly adsorption at low initial concentration, and precipitation-dominated at higher concentration.

Abstract P3-08-03: Dissecting the heterogeneity of metaplastic breast cancer: A morphological, immunohistochemical and genomic analysis of a large cohort

Although rare, Metaplastic Breast Carcinomas (MBC) account for significant global breast cancer mortality. This subgroup is extremely heterogeneous and by definition exhibits metaplastic change to squamous and/or mesenchymal elements, including but not limited to spindle, squamous, chondroid, osseous and rhabdomyoid elements. The WHO working group recognizes that the current classification is inadequate and in the interim, has suggested a purely descriptive classification. The mixed epithelial-mesenchymal morphology has led to speculation that MBC represent 'stem cell tumours'; in support of this, MBC have been shown to have a CD44+/CD24-/low phenotype. Clinically, patients present with tumours that are larger (higher stage), have increased likelihood of distant metastases at presentation and overall, have a reduced 5-year survival rate compared to Invasive Carcinoma-NST. Hence, this is a unique subtype with poor outcome but without a robust classification or understanding of the biology to aid clinical management. We present a detailed morphological, immunohistochemical and genomic analysis of a large series of MBC (n=347), as amassed through the Asia-Pacific MBC consortium. We consider our morphological dissection using the WHO subtyping guidelines and show that an increasing number of phenotypes in a mixed MBC (classified as WHO_1) significantly associates with a poor prognosis. Immunohistochemical analysis showed that a pure spindle (WHO_5) is significantly less likely to express vimentin, CK5/6, CK14, and CK19 than a mixed WHO_1 with spindle features. Similarly, a WHO_1 with chondroid features is less likely to express EGFR than WHO_1 with chondroid features and rhabdoid or osseous differentiation. Across the cohort, positivity for the AE1/3 antibody and a lack of EGFR expression both significantly associate with a better outcome. We report no significant association between patient age at diagnosis and breast cancer specific survival, nor between age and specific WHO MBC subtypes. We report a significant association between WHO_1 types and increasing tumour grade, and also between tumour size and grade, with tumour size being a highly significant prognostic indicator in this cohort. Our exome sequencing confirms a significant enrichment for TP53 and PTEN mutations in MBC, and intriguingly for concurrent mutations of TP53, PTEN and PIK3CA. A novel enrichment for NF1 mutations is also presented. In summary, we provide a thorough assessment of a large cohort of MBC, including morphology, survival, IHC and exome sequencing, and present our analysis contextualized by the WHO guidelines, extending the existing knowledge base of this rare tumour type.

Citation Format: McCart Reed AE, Kalaw E, Nones K, Bettington M, Lim M, Bennett J, Johnstone K, Kutasovic JR, Kazakoff S, Xu QC, Saunus JM, Reid LE, Black D, Niland C, Ferguson K, Gresshoff I, Raghavendra A, Liu JC, Kalinowski L, Reid AS, Davidson M, Pearson JV, Yamaguchi R, Harris G, Tse G, Papadimos D, Pathmanathan R, Pathmanathan N, Tan PH, Fox S, O'Toole S, Waddell N, Simpson PT, Lakhani SR. Dissecting the heterogeneity of metaplastic breast cancer: A morphological, immunohistochemical and genomic analysis of a large cohort [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-08-03.

Measurement of the Electron Antineutrino Oscillation with 1958 Days of Operation at Daya Bay

We report a measurement of electron antineutrino oscillation from the Daya Bay Reactor Neutrino Experiment with nearly 4 million reactor ν[over ¯]_{e} inverse β decay candidates observed over 1958 days of data collection. The installation of a flash analog-to-digital converter readout system and a special calibration campaign using different source enclosures reduce uncertainties in the absolute energy calibration to less than 0.5% for visible energies larger than 2 MeV. The uncertainty in the cosmogenic ^{9}Li and ^{8}He background is reduced from 45% to 30% in the near detectors. A detailed investigation of the spent nuclear fuel history improves its uncertainty from 100% to 30%. Analysis of the relative ν[over ¯]_{e} rates and energy spectra among detectors yields sin^{2}2θ_{13}=0.0856±0.0029 and Δm_{32}^{2}=(2.471_{-0.070}^{+0.068})×10^{-3}  eV^{2} assuming the normal hierarchy, and Δm_{32}^{2}=-(2.575_{-0.070}^{+0.068})×10^{-3}  eV^{2} assuming the inverted hierarchy.

[Relevant molecular characteristics analysis on malignant transformation of interstitial cells induced by tumor stem cells in glioma microenvironment]

Objective: A variety of interstitial cells in tumor microenvironment (TME) based on glioma stem cells(GSC) have the function to promote malignant progression of tumors, but whether these interstitial cells have already undergone malignant transformation and their related molecular characteristics are still poorly understood. Methods: Human SU3-RFP glioma stem cells (GSC) stably transfected with red fluorescent protein (RFP) and interstitial cells from enhanced green fluorescent protein (EGFP) transgenic nude mice were co-cultured in vitro. SU3-RFP cells were also inoculated in different tissues of EGFP-Balb/c nude mice. Immortal EGFP(+) cells were monocloned either from co-culture cells in vitro, or from their xenografts in vivo. These immortal EGFP(+) cells were confirmed to bear characteristics of tumor cell via chromosomal analysis and tumorigenicity assay. Related molecular phenotypes of these cells were further detected through RT-PCR, flow cytometry and immunochemistry(IHC) techniques. Results: (1) Two EGFP(+) cell lines were obtained in vitro, and 5 EGFP(+) cell lines were obtained in vivo tumorigenic experiments. Seven EGFP(+) cell lines all have characteristics of self-renewal, heteroploid of chromosomes and 100% tumorigenicity. (2) Cell surface marker analysis showed cell origin of these cell lines were macrophages (tMΦ1 and tMΦ2 ), dendritic cells (tDC1 and tDC2), fibroblasts (tFB), oligodendrocytes (tOG) and BMSC cells (tBMSC), respectively. (3)All of these seven cell lines co-expressed Sca-1 and c-myc, and have Sox-2 or Nanog expression also, which suggest that they may bear molecular characteristics of mesenchymal stem cells or pluripotent stem cells. Conclusions: (1) Tumor stromal cells in TME have undergone malignant transformation, which is related to the tissue remodeling of TME by GSCs, and not limit to the specific type of their parasitic tissues. (2) Tumor cells originated from GSC and tumor interstitial cells, respectively, are two major types of tumor cells with different origins in glioma parenchyma, can not be simply regarded as tumor heterogeneity, transformed interstitial cells of TME may have the potential to serve as new targets for target diagnosis and therapy.

[Experimental studies on correlation between nucleolus spindle-related protein 1 and the malignant progression and prognosis of human glioblastoma multiforme]

Objective: To investigate the correlation between nucleolus spindle-related protein 1 (NUSAP1) and malignant progression and prognosis of human glioblastoma multiforme (GBM). Methods: RT-PCR and immunohistochemical technique were applied to analyze NUSAP1 expression level in GBM surgical specimens. Correlations between NUSAP1 expression and molecular classification and survival of patients with GBM were also investigated in TCGA database. The gene silencing technique was used to silence NUSAP1 expression in U87 cells, CCK-8 assay was used to detect cell proliferation, flow cytometry was used to detect cell cycle changes, and in vivo tumorigenicity was evaluated after NUSAP1 silencing in tumor-bearing mice. Results: NUSAP1 expression level in GBM was higher than that in non-tumor brain tissue. Survival curve analysis showed that the survival time of GBM patients with high NUSAP1 expression decreased significantly (P<0.01). NUSAP1 expression was relatively lower in mesenchymal and neural molecular subtypes of GBM, when compared with the other two molecular subtypes. And it was closely related with specific genetic aberrations (such as PTEN loss and IDH1 mutation). Silencing NUSAP1 inhibited G2/M cell cycle progression of GBM cells, and inhibited cell proliferation both in vitro and in vivo. Conclusion: Expression of NUSAP1 is closely related to progress and prognosis of GBM, and can be a biomarker reflecting GBM prognosis and act as a therapeutic target with potential clinical application value.

Effect of precursor type on the reduction of concentrated nitrate using zero-valent copper and sodium borohydride

In this study, we demonstrated that the choice of precursor has a strong effect on the reduction of nitrate (NO₃^-) using zero-valent copper (Cu⁰) synthesized by sodium borohydride (NaBH₄). Different precursors: CuSO₄, CuO, Cu₂O, Cu powder, and Cu mesh were used to reduce NO₃^- at 677 mg-N/L under the reducing conditions of NaBH₄. Compared with the prehydrolyzed samples, those prepared without prehydrolysis exhibited lower reduction rates, longer times and higher concentrations of nitrite (NO₂^-) intermediate. It was found that one-time addition of NaBH₄ resulted in higher reduction rate and less NO₂^- intermediate than two-step addition. Results showed that Cu⁰ from CuSO₄ possessed the smallest particle size (890.9 nm), highest surface area (26.0 m²/g), and highest reaction rate (0.166 min^-1). Values of pseudo-first-order constant (k_obs) were in the order: CuSO₄ > CuO > Cu₂O > Cu powder >Cu mesh. However, values of surface area-normalized reaction rate (k_SA) were approximately equal. It was proposed that NO₃^- was reduced to NO₂^- on Cu⁰, and then converted to NH₄⁺ and N₂, respectively; H₂ generated from both NaBH₄ hydration and Cu (II) reduction contributed to NO₃^- reduction as well.

Autophagy inhibition increased the anti-tumor effect of cisplatin on drug-resistant esophageal cancer cells

The sensitivity of tumor cells to treatment can be affected by autophagy. The drug resistance of esophageal cancer cells against cisplatin occurs during the long period of chemotherapy drug treatment. This study was designed to observe the effect autophagy has on the occurrence of esophageal cancer cell drug resistance against cisplatin and investigate its molecular mechanism in order to provide new details and strategies for the clinical treatment of esophageal cancer, especially cisplatin treatment. The detection methods used in this study were 3-(4,5-dimethylthiazd-2-yl)-2,5-dipheny-ltetrazolium bromide (MTT) colorimetric assay, clone survival technique, small interfering RNA (siRNA) transfection, and Western blot. Autophagy is a protection mechanism of drug-resistant cells processed by cisplatin, and maintains the cell clone survival ability. Autophagy activation requires the involvement of Atg5 and Atg7.

Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

The Daya Bay experiment has observed correlations between reactor core fuel evolution and changes in the reactor antineutrino flux and energy spectrum. Four antineutrino detectors in two experimental halls were used to identify 2.2 million inverse beta decays (IBDs) over 1230 days spanning multiple fuel cycles for each of six 2.9 GW_{th} reactor cores at the Daya Bay and Ling Ao nuclear power plants. Using detector data spanning effective ^{239}Pu fission fractions F_{239} from 0.25 to 0.35, Daya Bay measures an average IBD yield σ[over ¯]_{f} of (5.90±0.13)×10^{-43}  cm^{2}/fission and a fuel-dependent variation in the IBD yield, dσ_{f}/dF_{239}, of (-1.86±0.18)×10^{-43}  cm^{2}/fission. This observation rejects the hypothesis of a constant antineutrino flux as a function of the ^{239}Pu fission fraction at 10 standard deviations. The variation in IBD yield is found to be energy dependent, rejecting the hypothesis of a constant antineutrino energy spectrum at 5.1 standard deviations. While measurements of the evolution in the IBD spectrum show general agreement with predictions from recent reactor models, the measured evolution in total IBD yield disagrees with recent predictions at 3.1σ. This discrepancy indicates that an overall deficit in the measured flux with respect to predictions does not result from equal fractional deficits from the primary fission isotopes ^{235}U, ^{239}Pu, ^{238}U, and ^{241}Pu. Based on measured IBD yield variations, yields of (6.17±0.17) and (4.27±0.26)×10^{-43}  cm^{2}/fission have been determined for the two dominant fission parent isotopes ^{235}U and ^{239}Pu. A 7.8% discrepancy between the observed and predicted ^{235}U yields suggests that this isotope may be the primary contributor to the reactor antineutrino anomaly.

Flotation separation of strontium via phosphate precipitation

Flotation separation of strontium (Sr) from wastewater via phosphate precipitation was investigated. While 37.33% of Sr precipitated at highly alkaline pH in the absence of PO₄^3-, it completely precipitated as Sr₃(PO₄)₂ at a molar ratio ([PO₄^3-]:[Sr²⁺]) of 0.62 at a lower pH value. The presence of Ca²⁺ hindered Sr precipitation, yet it could be overcome by increasing the PO₄^3- dose. Sodium dodecyl sulfate (SDS) was a better collector for dispersed air flotation of Sr₃(PO₄)₂ than cetyl trimethyl ammonium bromide, or mixed collector systems of SDS and saponin. The highest separation efficiency of 97.5% was achieved at an SDS dose of 40 mg/L. The main mechanism in the precipitate flotation is adsorption of anionic SDS on the positively charged surface of colloidal Sr₃(PO₄)₂ via electrostatic interaction. SDS enhanced the aggregation of Sr₃(PO₄)₂ precipitates as the size increased from 1.65 to 28.0 μm, which was beneficial to separation as well.

[The multicenter study on the registration and follow-up of low anticoagulation therapy for the heart valve operation in China]

OBJECTIVE

To investigate the optimal anticoagulation methods and monitoring strategy for Chinese patients undergoing heart valve replacement, which is potentially quite different from western populations.

METHODS

In this multicenter prospective cohort study, the anticoagulation and monitoring strategy data was acquired from 25 773 in-hospital patients in 35 medical centers and 20 519 patients in outpatient clinic in 11 medical centers from January 1st, 2011 to December 31th, 2015.

RESULTS

As for in-hospital patients, mean age of study population was (48.6±11.2) years old; main etiology of valve pathology was rheumatic (87.5%) origin among study cohort; 94.8% of study population received mechanical valve implantation; international normalized ratio (INR) monitoring (in all the study centers) and low-intensity anticoagulation strategy (31 hospitals chose target INR range of 1.5-2.5, and actual values of INR among 89.2% of 100 069 in-hospital monitoring samples were 1.5-2.5), with mean actual INR values of 1.84±0.53, and warfarin dosage of (2.82±0.93) mg/d were widely adopted among the study centers; strategies of in-hospital warfarin administration were similar in all the study centers; complication rates of low-intensity anticoagulation strategy were low in severe hemorrhage (0.02%), thrombosis (0.05%), and thromboembolism (0.05%) events, without anticoagulation-related death.As for 18 974 outpatient clinic patients, the follow-up rate was 92.47%, with a total of 30 012 patient-years (Pty). Anticoagulation-related morbidity and mortality rates were 0.67% and 0.15% Pty; major hemorrhage morbidity and mortality rates were 0.25% and 0.13% Pty; thromboembolism morbidity and mortality rates were 0.45% and 0.03% Pty.The mean dosage of warfarin daily dosage was (2.85±1.23) mg/d and INR value was 1.82±0.57.No significant regional difference in the intensity of anticoagulation therapy was noted during the study.

CONCLUSIONS

INR can be used as a normalized indicator for intensity of anticoagulation therapy in China.The optimal anticoagulation intensity with INR range from 1.5 to 2.5 is safe and effective for Chinese patients with heart valve replacement, and there is no significant regional difference in the intensity of anticoagulation therapy.

Psychological distress and type 2 diabetes mellitus: a 4-year policemen cohort study in China

OBJECTIVES

This study investigated whether psychological distress predicts the development of type 2 diabetes mellitus (T2DM) and if the association differs between populations at a high or low diabetes risk level among Chinese police officers.

DESIGN

Prospective cohort study.

SETTING

Single centre.

PARTICIPANTS

6559 participants underwent clinical measurements at the hospital in April 2007. 5811 police officers participated in the follow-up consisting of new-onset diabetes (NOD) events occurring annually between 2008 and 2011.

PRIMARY OUTCOME MEASURES

Baseline data were collected from policemen who completed the Symptom Checklist 90-Revised (SCL-90-R) questionnaire and a self-designed questionnaire. Psychological distress was measured by the SCL-90-R questionnaire. Hong Kong Chinese Diabetes Risk Score (HKCDRS) was used to evaluate the risk of T2DM, and the participants were divided into low-risk group and high-risk group based on the HKCDRS. Cox proportional hazards regression was used to calculate the HRs of the incidence of T2DM related to psychological distress and further stratified the analysis based on HKCDRS.

RESULTS

Among 5811 participants, 179 subjects developed NOD during the 4-year follow-up. 54 subjects (1.63%) with a HKCDRS 0-7 vs 125 subjects (4.98%) with a HKCDRS>7 developed NOD (p<0.05). There was a significant association between psychological distress and T2DM (HR=1.46; 95% CI 1.05 to 2.02). Among the participants with a high-risk score (HKCDRS>7), 7.07% of those with psychological distress developed T2DM compared with 4.43% of participants without psychological distress (p<0.05). The corresponding adjusted HR for psychological distress was 1.61 (95% CI 1.10 to 2.37).

CONCLUSIONS

Psychological distress is an independent risk factor for T2DM in this prospective cohort study. Stratification analysis indicated that psychological distress was associated with T2DM in a high-risk level population.

Limits on Active to Sterile Neutrino Oscillations from Disappearance Searches in the MINOS, Daya Bay, and Bugey-3 Experiments

Searches for a light sterile neutrino have been performed independently by the MINOS and the Daya Bay experiments using the muon (anti)neutrino and electron antineutrino disappearance channels, respectively. In this Letter, results from both experiments are combined with those from the Bugey-3 reactor neutrino experiment to constrain oscillations into light sterile neutrinos. The three experiments are sensitive to complementary regions of parameter space, enabling the combined analysis to probe regions allowed by the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE experiments in a minimally extended four-neutrino flavor framework. Stringent limits on sin^{2}2θ_{μe} are set over 6 orders of magnitude in the sterile mass-squared splitting Δm_{41}^{2}. The sterile-neutrino mixing phase space allowed by the LSND and MiniBooNE experiments is excluded for Δm_{41}^{2}<0.8  eV^{2} at 95%  CL_{s}.

Improved Search for a Light Sterile Neutrino with the Full Configuration of the Daya Bay Experiment

This Letter reports an improved search for light sterile neutrino mixing in the electron antineutrino disappearance channel with the full configuration of the Daya Bay Reactor Neutrino Experiment. With an additional 404 days of data collected in eight antineutrino detectors, this search benefits from 3.6 times the statistics available to the previous publication, as well as from improvements in energy calibration and background reduction. A relative comparison of the rate and energy spectrum of reactor antineutrinos in the three experimental halls yields no evidence of sterile neutrino mixing in the 2×10^{-4}≲|Δm_{41}^{2}|≲0.3  eV^{2} mass range. The resulting limits on sin^{2}2θ_{14} are improved by approx imately a factor of 2 over previous results and constitute the most stringent constraints to date in the |Δm_{41}^{2}|≲0.2  eV^{2} region.

Apoptosis, proliferation, and morphology during vein graft remodeling in rabbits

Neo-intima development and atherosclerosis limit the long-term use of vein grafts for revascularization of ischemic tissues. Recently, studies have confirmed that proliferating cell nuclear antigen (PCNA) plays an important role in cell proliferation. Our research confirmed that 28 days after vein transplantation, PCNA expression increases significantly. Using rabbits, rather than rodents, for a more representative model of human vein grafts, we aimed to establish a time course of changes in cell proliferation and apoptosis using morphometric and immunohistochemical analyses, western blot, terminal deoxynucleotidyl transferase dUTP nick end labeling, and transmission electron microscopy (TEM). The external jugular veins of 42 healthy purebred male New Zealand white rabbits were grafted onto their common carotid arteries. The rabbits were divided into seven groups, with vein grafts being harvested before surgery, and at 1, 3, 7, 14, 28, and 90 days afterwards. The extent of stenosis and apoptosis, PCNA protein levels, and TEM morphology were subsequently examined. Intimal thickness was slightly decreased 1 day following surgery, but then increased continuously until the 90th day. Western blot and immunohistochemistry both indicated lowered PCNA expression on day 1, although levels subsequently increased, peaking at 7 days post-surgery. After surgery, apoptosis was lowest on day 7, and remained low thereafter. TEM revealed signs of apoptosis as vein graft restenosis progressed. Proliferation and apoptosis co-occurred following grafting, indicating that both processes were involved in vein graft remodeling. Apoptosis levels were highest between days 1 and 3 after surgery, whereas proliferation culminated on the 7th day.

Mutational analysis of HOXA10 gene in Chinese patients with cryptorchidism

Cryptorchidism is one of the most common congenital anomalies and affects 2-4% of full-term new born boys. Its aetiology is poorly understood at present. HOXA10 plays a pivotal role in regulation of testicular descent. Male mice mutant for Hoxa10 exhibit unilateral or bilateral cryptorchidism as a result of impaired development of the gubernaculums. In this study, we performed mutation analysis of HOXA10 gene in a cohort of 98 cryptorchid patients. And we found a mutation (N27K) in a boy with unilateral cryptorchidism. The mutation was not detected in 106 healthy controls. Both in silico analyses and functional studies showed that the mutation affected the function of HOXA10. The results demonstrated that mutation in HOXA10 gene contributes to the pathogenesis of cryptorchidism, but may not be a common cause.

Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18)  cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43)  cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.

Fractionation and release behaviors of metals (In, Mo, Sr) from industrial sludge

Little is known on the fate of rare metals in the environment and the associated risks. The fractionation and release of three metals of an industrial sludge were assessed. The average concentration ranges from 39.3 to 41.5 mg/kg for indium (In), 43.1-77.8 mg/kg for molybdenum (Mo), and 131.1-376.4 mg/kg for strontium (Sr). Sequential extraction results implied that In was mobile, while Mo and Sr were immobile. However, experimental results from effects of Eh/pH revealed that In was slightly mobile under acidic (pH 4.5) in Eh range of 210-260 mV, and immobile under alkaline conditions (9.0) in Eh range of -250 to 125 mV. The release of Mo was slightly mobile under acidic conditions. However, Mo was very mobile under alkaline conditions and it increased with decreasing Eh. The release of Sr was significant under acidic conditions; however, it was immobile under alkaline conditions. Solubility and adsorption as affected by pH, and speciation could explain their release behaviors. Discrepancy in predictions from sequential extraction and actual observation from Eh/pH experiments was discussed.

New measurement of antineutrino oscillation with the full detector configuration at Daya Bay

We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×10^{5} GW_{th}  ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six ^{241}Am-^{13}C radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin^{2}2θ_{13} and |Δm_{ee}^{2}| were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin^{2}2θ_{13}=0.084±0.005 and |Δm_{ee}^{2}|=(2.42±0.11)×10^{-3}  eV^{2} in the three-neutrino framework.

Reduction of concentrated nitrate by using in situ synthesized zero-valent copper

Although zero-valent iron represents a promising approach for reduction of nitrate (NO(3)(-)) in water, its application in concentrated nitrate is limited by surface passivation. In this study, an alternative approach using in situ synthesized zero-valent copper (Cu(0)) produced by borohydride (NaBH(4)) was investigated. Complete reduction was observed within 55 min by reacting 677 mg-N/L of NO(3)(-) with CuO (0.312 g/L) and NaBH(4) (4.16 g/L) at 60 °C. The pseudo-first-order rate constant was 0.059 min(-1), and it increased threefold when the CuO dose was increased to 1.24 g/L. Increasing the NaBH(4) dose produced less nitrite (NO(2)(-)) throughout the experiments, indicating that it is the primary agent for reducing NO(2)(-). The initial pH exerted a significant effect on the reaction rate, and NO(3)(-) was rapidly reduced when the initial pH was less than 4. Based on the research findings, possible reaction pathways for NO(3)(-) reduction by Cu(0) are proposed in this work.

Search for a light sterile neutrino at Daya Bay

A search for light sterile neutrino mixing was performed with the first 217 days of data from the Daya Bay Reactor Antineutrino Experiment. The experiment's unique configuration of multiple baselines from six 2.9 GW(th) nuclear reactors to six antineutrino detectors deployed in two near (effective baselines 512 m and 561 m) and one far (1579 m) underground experimental halls makes it possible to test for oscillations to a fourth (sterile) neutrino in the 10(-3) eV(2)<|Δm(41)(2) |< 0.3 eV(2) range. The relative spectral distortion due to the disappearance of electron antineutrinos was found to be consistent with that of the three-flavor oscillation model. The derived limits on sin(2) 2θ(14) cover the 10(-3) eV(2) ≲ |Δm(41)(2)| ≲ 0.1 eV(2) region, which was largely unexplored.

Microalgae harvesting by flotation using natural saponin and chitosan

This study aims to investigate the harvesting of microalgae by dispersed air flotation (DiAF) using natural biosurfactant saponin as the collector and chitosan as the flocculant. Two types of microalgae, Chlorella vulgaris and Scenedesmus obliquus, were used in this study. It was observed that saponin was a good frother, but not an effective collector when used alone for flotation separation of algae. However, with the pre-flocculation of 5 mg/L of chitosan, separation efficiency of >93% microalgae cells was found at 20 mg/L of saponin. Removal efficiency of >54.4% and >73.0% was found for polysaccharide and protein, respectively at 20 mg/L of saponin and chitosan each. Experimental results show that DiAF using saponin and chitosan is effective for separation of microalgae, and algogenic organic matter (AOM). It can potentially be applied in the integrated microalgae-based biorefinery.

Mesenteric lymph reperfusion exacerbates spleen injury caused by superior mesenteric artery occlusion shock

The intestinal lymph pathway plays an important role in the pathogenesis of organ injury following superior mesenteric artery occlusion (SMAO) shock. We hypothesized that mesenteric lymph reperfusion (MLR) is a major cause of spleen injury after SMAO shock. To test this hypothesis, SMAO shock was induced in Wistar rats by clamping the superior mesenteric artery (SMA) for 1 h, followed by reperfusion for 2 h. Similarly, MLR was performed by clamping the mesenteric lymph duct (MLD) for 1 h, followed by reperfusion for 2 h. In the MLR+SMAO group rats, both the SMA and MLD were clamped and then released for reperfusion for 2 h. SMAO shock alone elicited: 1) splenic structure injury, 2) increased levels of malondialdehyde, nitric oxide (NO), intercellular adhesion molecule-1, endotoxin, lipopolysaccharide receptor (CD14), lipopolysaccharide-binding protein, and tumor necrosis factor-α, 3) enhanced activities of NO synthase and myeloperoxidase, and 4) decreased activities of superoxide dismutase and ATPase. MLR following SMAO shock further aggravated these deleterious effects. We conclude that MLR exacerbates spleen injury caused by SMAO shock, which itself is associated with oxidative stress, excessive release of NO, recruitment of polymorphonuclear neutrophils, endotoxin translocation, and enhanced inflammatory responses.

Spectral measurement of electron antineutrino oscillation amplitude and frequency at Daya Bay

A measurement of the energy dependence of antineutrino disappearance at the Daya Bay reactor neutrino experiment is reported. Electron antineutrinos (ν¯(e)) from six 2.9  GW(th) reactors were detected with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls. Using 217 days of data, 41 589 (203 809 and 92 912) antineutrino candidates were detected in the far hall (near halls). An improved measurement of the oscillation amplitude sin(2)2θ(13)=0.090(-0.009)(+0.008) and the first direct measurement of the ν¯(e) mass-squared difference |Δm(ee)2|=(2.59(-0.20)(+0.19))×10(-3)  eV2 is obtained using the observed ν¯(e) rates and energy spectra in a three-neutrino framework. This value of |Δm(ee)2| is consistent with |Δm(μμ)2| measured by muon neutrino disappearance, supporting the three-flavor oscillation model.

Enhanced adsorption of quaternary amine using modified activated carbon

This study examined different methodologies to modify activated carbon (AC) for the removal of quaternary amine, tetramethylammonium hydroxide (TMAH), from water. Commercial carbon (WAC) was treated by nitric acid oxidation (NA-WAC), silica impregnation (SM-WAC0.5), and oxygen plasma (P10-WAC), and their characteristics and adsorption capacity were compared. The Langmuir model fitted the equilibrium adsorption data well under different pH. The maximum adsorption capacity of WAC was 27.77 mg/g, while those of NA-WAC, SM-WAC 0.5, and P10-WAC were 37.46, 32.83 and 29.03 mg/g, respectively. Nitric acid oxidation was the most effective method for enhancing the adsorption capacity of TMAH. Higher pH was favorable for TMAH adsorption. Desorption study revealed that NA-WAC had no considerable reduction in performance even after five cycles of regeneration by 0.1 N hydrochloric acid. It was proposed that electrostatic interaction was the main mechanism of TMAH adsorption on activated carbon.

Oxidative removal of arsenite by Fe(II)- and polyoxometalate (POM)-amended zero-valent aluminum (ZVAl) under oxic conditions

Abiotic transformation of As(III) to As(V) is possible which would decrease As toxicity. This study investigated the potential applications of zero-valent Al (ZVAl) or Al wastes, such as Al beverage cans, for converting As(III) to As(V) in an acidic solution under aerobic conditions. Results showed that As(III) could not be oxidized by ZVAl within 150 min reaction at pH 1 because of the presence of an oxide layer on ZVAl. However, 85 μM As(III) could be completely oxidized with the addition of Fe(II) or POM due to the generation of a Fenton reaction or the enhancement of H2O2 production, respectively, on the ZVAl surfaces. Because Fe(II) or polyoxometalate (POM) exhibited more stable at low pH and scavenged rapidly the H2O2 produced on the aerated ZVAl surfaces, OH radical productions were more efficient and As(III) was rapidly oxidized in the ZVAl/O2 system with theses two catalysts. The catalytic oxidation kinetics of As(III) in the presence of Fe(II) or POM were best described by zero-order reaction, and the rate constants increased with a decrease of pH from 2 to 1. Following the oxidative conversion of As(III) to As(V) in the ZVAl/Fe/O2 system, As(V) was removed by the newly formed hydrous Al/Fe precipitates by increasing the solution pH to 6. Nonetheless, the As(V) removal was incomplete in the ZVAl/POM/O2 system because the hydrolyzed products of POM, e.g., PO4(3-), inhibited As(V) removal due to the competitive adsorption of the oxyanion on Al precipitates. Discarded Al-based beverage cans exhibit a higher efficiency for As(III) oxidation and final As removal compared with that of ZVAl, and thus, the potential application of Al beverage cans to scavenge As in solutions is feasible.

Effects of ozone and peroxone on algal separation via dispersed air flotation

Effects of pre-oxidation on algal separation by dispersed air flotation were examined. Ozone (O3) and peroxone (O3 and H2O2) could induce cell lysis, release of intracellular organic matter (IOM), and mineralization of organic substances. Separation efficiency of algal cells improved when pre-oxidized. Total of 76.4% algal cells was separated at 40 mg/L of N-cetyl-N-N-N-trimethylammonium bromide (CTAB), while 95% were separated after 30-min ozonation. Pre-oxidation by ozone and peroxone also enhanced flotation separation efficiency of dissolved organic carbon (DOC), polysaccharide, and protein, in which peroxone process exerted more significantly than O3. Two main mechanisms were involved in flotation separation of unoxidized algal suspension, namely hydrophobic cell surface and cell flocculation resulting from CTAB adsorption. However, flocculation by CTAB was hindered for pre-oxidized algal suspensions. It implied that the compositional changes in extracellular organic matter (EOM) by pre-oxidation were more determined for flotation separation of pre-oxidized cells.

Effect of O3 and O3/H2O2 on algae harvesting using chitosan

We examined the effects of pre-oxidation using ozone (O3) and a combination of O3 and hydrogen peroxide (O3/H2O2) on algae suspensions and their harvesting. Inactivation of algae cells, release of intracellular organic matter (IOM), mineralization of extracellular organic matter (EOM), and changes in molecular weight distribution of EOM were found after pre-oxidation. Enhanced separation efficiency of turbidity, dissolved organic carbon (DOC), protein, and polysaccharide using chitosan and polyaluminum chloride (PACl) was found after pre-oxidation, especially when algae cells were subject to O3/H2O2. Chitosan showed higher efficiency than PACl. Judging from the remarkable increase in floc size, it was proposed that released IOM formed complexes with cationic chitosan and resulted in enhanced dual flocculation and facilitated algae separation.