The Al 4 C 3 -formed interfacial reaction plays an important role in tuning the mechanical and thermal properties of carbon/aluminum (C/Al) composites reinforced with carbonaceous materials such as multi-wall carbon nanotube (MWCNT) and graphene nanosheet. In terms of the hydrolysis nature of Al 4 C 3 , an electrochemical dissolution method was developed to quantitatively characterize the extent of C/Al interfacial reaction, which involves dissolving the composite samples in alkaline solution first, then collecting and measuring the CH 4 gas released by Al 4 C 3 hydrolysis with a gas chromatograph. Through a case study with powder metallurgy fabricated 2.0 wt.% MWCNT/Al composites, the detectability limit of the proposed method is 0.4 wt.% Al 4 C 3 , corresponding to 5 % extent of interfacial reaction with a measurement error of ±3 %. And then, with the already known MWCNT/Al reaction extent vs different sintering temperature and time, the reaction kinetics with an activation energy of 281 kJ mol -1 was successfully derived. Therefore, this rapid, sensitive, accurate method supplies an useful tool to optimize the processing and properties of all kinds of C/Al composites via interface design/control.

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Background. Bone metastasis (BM) has been proven to be responsible for the poor prognosis of primary malignant bone neoplasms (PMBNs). We aimed to identify the prevalence, risk factors, and prognostic factors for PMBNs patients with BM based on the Surveillance, Epidemiology, and End Results (SEER) database. Methods. 4,758 patients diagnosed with PMBNs from 2010 to 2018 were selected from the SEER database. All patients were divided into two groups: the BM group or the non-BM group. Pearson’s chi-square test and Fisher’s exact method were used to assess baseline characteristics, and logistic regression analysis was applied to assess risk factors. In addition, a nomogram was constructed based on the results of Cox regression analysis among 227 patients with BM. The good performance and clinical applicability of the nomogram were tested by the concordance index, operating characteristic curve, area under the curve, calibration curves, and decision curve analysis. Results. 227 (4.8%) patients had metastasis to bone at diagnosis. Primary site outside the extremities (axial: odds ratio, OR = 1.770 ; others: OR = 1.951 ), Ewing sarcoma ( OR = 2.845 ), larger tumor size (5–8 cm: OR = 3.403 ; >8 cm: OR = 5.562 ), tumor extension beyond the periosteum ( OR = 2.477 ), and regional lymph node metastasis ( OR = 2.900 ) were associated with a higher risk of BM at the initial diagnosis of PMBNs. Five independent prognostic factors were found in the survival analysis: pathological type (chondrosarcoma vs. osteosarcoma: hazard ratio, HR = 0.342 ; Ewing sarcoma vs. osteosarcoma: HR = 0.592 ; and chordoma vs. osteosarcoma: HR = 0.015 ), marital status ( HR = 2.457 ), pulmonary metastasis ( HR = 1.934 ), surgery at the primary site ( HR = 0.164 ), and chemotherapy ( HR = 0.084 ). A nomogram based on these prognostic factors could be a good predictor of cancer-specific survival. Conclusions. We identified the prevalence, risk factors, and prognostic factors correlated with BM in PMBNs patients. The related nomogram could be a practical tool for therapeutic decision-making and individual counseling.

Background: Through previous studies and clinical practice, we have found that real-time ultrasoundguided (UG) spinal anesthesia (SA) and traditional landmark-guided (LG) SA each require a different minimum local anesthetic dose (MLAD) of ropivacaine. For this study, we used Dixon's up-and-down sequential method to analyze and compare the MLAD of different ropivacaine concentrations required for the UG and LG SA methods.Methods: A total of 120 patients undergoing knee surgery were consecutively recruited and randomly divided into four groups (30 patients per group). These groups were categorized as follows: Group I: high ropivacaine ultrasound-guided (HRUG), Group II: low ropivacaine ultrasound-guided (LRUG), Group III: high ropivacaine landmark-guided (HRLG), and Group IV: low ropivacaine landmark-guided (LRLG). SA was established by a bolus administration of up-and-down doses of 0.75% or 0.5% plain ropivacaine. Initial doses of 16, 18, 12, and 14 mg were administered to groups I-IV, and after that, increased or decreased by 1.5 mg according to dose effectiveness. Upon identifying the intervertebral puncture level, a lumbar X-ray was performed with metal markers, and actual radiographic findings were identified and compared to the initial markings.Results: For UG groups, the MLAD in the LRUG group was significantly higher than in the HRUG

Background To determine the necessity of tourniquet use in arthroscopic meniscal repair by comparing outcomes including arthroscopic visibility, operative time, postoperative pain and subjective function of the knee joint. Methods This was a retrospective, single-centre, single-surgeon study. A total of 148 patients who underwent arthroscopic meniscal repair were allocated to the tourniquet group (n=82) or the nontourniquet group (n=66). The primary outcome measures were arthroscopic visibility and operative time. The secondary outcomes were postoperative pain measured by a visual analogue scale and subjective function of the knee joint measured by The International Knee Documentation Committee (IKDC) and Lysholm scores. Results The 2 groups did not differ in terms of age, male‒female ratio, body mass index, or operative side. There was no significant difference between the 2 groups regarding arthroscopic visibility and operative time. At 1 week postoperatively, the VAS score and Lysholm score of the nontourniquet group were better than those of the tourniquet group (P<0.05). The VAS score, Lysholm score, and IKDC score at 6 weeks and 3 months postoperatively were significantly improved compared to the preoperative status in both groups (P < 0.05). However, there was no significant difference in these indexes between the two groups at 6 weeks and 3 months postoperatively (P > 0.05). Conclusions Tourniquet use for arthroscopic meniscal repair does not affect primary outcome or secondary outcomes. Based on the results of the analysis, the use of a tourniquet is no longer advisable for routine arthroscopic meniscal repair. Level of Evidence：LEVEL III