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The newly built back-streaming white neutron beam line (Back-n) at China spallation Neutron Source (CSNS) makes a breakthrough for China's domestic nuclear data measurement, which is pushing nuclear data measurement in China towards higher precision and wider energy range. The neutron flux of the facility was measured at the first beginning since it is an extremely important characterization for the experiment proposal and data analysis. The neutron fluxes under big collimators in end station 1 (ES#1) and end station 2 (ES#2) had been characterized by a fission chamber. In this paper, the first measurement of the neutron flux of Back-n ES#1 with small collimators is reported. The neutron flux from 0.5 eV to 300 MeV was measured by three detectors: a silicon monitor based on a 6LiF sample for the energy range below 200 keV, a fast multi-layer fission ionization chamber for the range from 10 keV to 300 MeV, and a proton recoil telescope for the high energy region from 10 to 70 MeV. The flux and its uncertainty with 50 bins per decade were finally evaluated by combining the data of the three detectors. The integrated flux in the full energy range at CSNS beam power of 100 kW is 1.642 × 106 n/cm2/s, which is consistent with the FLUKA simulation within a difference of about 4%. [ABSTRACT FROM AUTHOR]

Forearm rotation restriction (FRR) is common after surgery for distal radius fractures (DRFs). The aim of the current study was to investigate the effect of DRFs on forearm rotation. This retrospective study reviewed patients with DRFs who underwent surgical treatment from January 2019 to December 2021. The patients' basic data and radiographic parameters were analyzed. Forearm rotation, including pronation and supination, was assessed using a standard goniometer. The Patient-Rated Wrist Evaluation (PRWE) score was evaluated, and the incidence of FRR at the 6-month follow-up was recorded. Univariate and multivariate logistic regression analyses were performed to identify risk factors correlated with FRR. A total of 127 patients with DRFs were included in this study. After surgery, 46 cases were considered to have FRR, with a rate of 36.2%, while the remaining 81 cases (63.8%) did not have FRR. The PRWE scores were 22.8 ± 5.2 and 17.9 ± 4.2 in the FRR group and non-FRR group, respectively, and the difference was statistically significant (P < 0.05). Multivariate analysis showed that the involvement of the sigmoid notch (OR, 2.88; 95% CI 1.49–5.56), post-operative volar tilt < 0° (OR, 2.16; 95% CI 1.34–3.50), and post-operative ulnar variance > 0 mm (OR, 1.37; 95% CI 1.06–1.78) were independently associated with the incidence of FRR. The FRR is associated with an increased PRWE score and may have had some impact on the patient's daily life. Fractures involving the sigmoid notch, dorsal angulation, and radial shortening deformity were found to be correlated with the incidence of FRR. Preoperative risk notification and intraoperative preventive measures are necessary for these patients. [ABSTRACT FROM AUTHOR]

The neutron capture cross section of 232 T h has been measured with the time-of-flight technique in the energy range from 10 to 200 keV at the back-streaming white neutron beam-line (Back-n) of China Spallation Neutron Source (CSNS). The pulse height weighting technique (PHWT) was applied with four C 6 D 6 liquid scintillators to measure the prompt gamma-ray energy release following neutron capture. The measurement data, corrected with the PHWT, have been normalized to the saturated resonances at 21.8 eV. The background was determined by a lead sample measurement and detailed Monte Carlo simulations. The 232 T h (n , γ) average cross sections have been determined relative to the 197 A u (n , γ) reaction cross sections. The results are consistent with the evaluation values of CENDL-3.2 and JENDL-5. The total uncertainties, including the PHWT, normalization, background subtraction, corrections, and relative measurement, are in the range of 4.5–4.8%. [ABSTRACT FROM AUTHOR]

Neutron-induced uranium fission reactions play an essential role in advanced nuclear energy research, basic and applied nuclear science. Based on the China Spallation Neutron Source (CSNS) Back-streaming white neutron source (Back-n), the measurement of the 236,238U fission cross sections relative to 235U from the threshold to 200 MeV was carried out by using time-of-flight (TOF) method with a multi-cell fast fission ionization chamber in double-bunch mode. The TOF spectra in double-bunch mode were unfolded by using Bayesian method. The fission cross section ratios of 238U/235U and 236U/235U were obtained. The experimental data of the 236,238U/235U fission cross section ratios measured in single-bunch mode were re-analyzed in high energy region and the upper limit was extended to 200 MeV for comparison. The experimental results in double-bunch mode are in good agreement with those in single-bunch mode and the main evaluation data within experimental uncertainties. The 236,238U(n,f) cross sections were obtained from the measured ratios and the standard 235U(n,f) cross sections and they agree well with the theoretical calculation, previous experiments, main evaluations and IAEA NDS. The experimental results can provide technical support for further experimental researches in double-bunch mode and relevant nuclear data evaluations. [ABSTRACT FROM AUTHOR]

Aims: This study aims to compare the outcomes of intramedullary nail (IMN) and volar locking plate (VLP) fixation for treatment of extra-articular or simple intra-articular distal radius fractures.Methods: PubMed, Embase, Medline and Cochrane Collaboration Central databases were searched for studies that compared the results of IMN and VLP fixation for the treatment of distal radius fractures up to March 2016. Stata 11.0 was used to perform the meta-analysis.Results: Six randomized controlled trials (RCT) and two retrospective studies were included in this review, including 463 patients. No significant differences were found between two treatment methods in terms of any functional score, radiographic parameters and motion range in the late post-operative period (6, 12 and 24 months). However, IMN did better than VLP at the post-operative six weeks and three months, no matter which functional scoring system was used. The incidence of carpal tunnel syndrome (CTS) was 8.7% in the VLP group, significantly higher than that (0.8%) in the IMN group (OR, 0.183; 95%CI, 0.045-0.74). But for other complications, such as infection (OR, 0.449; 95%CI, 0.095-2.114), tendious damage (OR, 0.931; 95%CI, 0.238-3.648), tenosynovitis (OR, 0.806; 95%CI, 0.209-3.108), algodystrophy (pain) (OR, 0.795; 95%CI, 0.291-2.173) and radial nerve paraesthesia (OR, 1.8143; 95%CI, 0.834-3.942), no significant differences were found (P > 0.05).Conclusions: Compared to VLP, IMN could provide better early postoperative functional outcomes and reduce the incidence of carpal tunnel syndrome, which could be of particular help in restoring confidence for workers with specialized manual skills to return to their prior jobs. Additionally, the conclusion should be cautiously treated, because it was reached in the context of limited amount of studies and relatively small sample size. Therefore, future studies with good design and large samples are required to verify this conclusion. [ABSTRACT FROM AUTHOR]

Novel micromechanical curved beam models were presented for predicting the tensile and shear moduli of triaxial weave fabric (TWF) composites by considering the interactions between the triaxial yarns of 0° and ±60°. The triaxial yarns in micromechanical representative unit cell (RUC) were idealized as curved beams with a path depicted using the sinusoidal shape functions, and the tensile and shear moduli of TWF composites were derived by means of the strain energy approach founded on micromechanics. In order to validate the new models, the predictions were compared with the experimental data from literature. It was shown that the predictions from the new model agree well with the experimental results. Using these models, the tensile and shear properties of TWF composites could be predicted based only on the properties of basic woven fabric. [ABSTRACT FROM AUTHOR]