Preparation of Silver Nanowires Flexible Electrode for Electrochemical Detection of Trace Copper in Water / 分析化学

A silver nanowires(AgNWs) flexible electrode was prepared using polydimethylsiloxane (PDMS) as the substrate and AgNWs as the conductive layer. It is easier to change the shapes and sizes of the flexible electrode due to its excellent stretchability and foldability. A square wave stripping voltammetry (SWSV) method for the detection of trace copper in water was established using the electrode as the working electrode.The characterization of AgNWs flexible electrode showed that the spread of AgNWs was uniform and the average resistance was 1.03 Ω. The data of electrochemical analysis showed that the properties of the electrode were superior to commercialized gold electrode and silver electrode. The effects of Bi3+concentration, supporting electrolyte,pH value, enrichment potential and enrichment time were determined and optimized. We achieved the sharpest and highest peak of the SWSV curves for the detection of Cu2+in the range of-0.3-0.3 V,which means the most sensitive detection, under the following conditions such as 0.5 mg/L Bi3+,0.1 mol/L support electrolyte tartaric acid-sodium tartrate solution (pH, 4.8), 0.6 V of enrichment potential, and 600 s of enrichment time. Under such conditions, the linear detection range of Cu2+concentration was from 0.001 mg/L to 0.100 mg/L and the detection limit was 9.27×10-5mg/L. The advantages of this detection method are fast speed,high sensitivity and wide detection range. Therefore,it can not only meet the requirements for the copper ion detection but also provide a new method or experimental basis for the detection of other metal ions in water. In addition, the AgNWs flexible electrode has great potential in detections under special circumstances or instantaneous detections due to its wonderful flexibility and biocompatibility.

Characteristics and risk factors of lymph node metastases in esophageal carcinoma / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the status of lymph node metastases (LNM) of esophageal carcinoma and to identify the risk factors.</p><p><b>METHODS</b>Clinical data of 308 patients who underwent esophagectomy with three-field lymphadenectomy during January 2006 and December 2010 were reviewed. Characteristics of LNM were studied.</p><p><b>RESULTS</b>The average number of dissected lymph nodes was 35.6 ± 14.5 in 308 patients. There were 197 patients(64%) had LNM. Logistic regression analysis showed that lymphatic vessel invasion(P=0.019) and deep tumor invasion(P<0.001) were risk factors of LNM. The highest LNM site was paratracheal node(25.0%). The incidence of cervical LNM was 14.1% in the middle thoracic carcinoma, higher than that of upper thoracic (7.3%) and lower thoracic (8.3%). Rate of LNM was lower in upper thoracic carcinomas than that in middle or lower ones(P=0.001). No significant difference of LNM was found among upper, middle and lower thoracic carcinoma for cervical or thoracic nodes. Lymphatic vessel invasion(P<0.001) and metastases in paratracheal lymph nodes (P=0.014) were risk factors for cervical LNM.</p><p><b>CONCLUSIONS</b>LNM of esophageal carcinoma can be found in both directions vertically and skipped metastasis. Paratracheal lymph nodes involvement is an indicator for cervical lymphadenectomy in thoracic esophageal carcinoma.</p>

Functional reconstruction of the medial collateral ligament with double-bundle allograft technique / 中华外科杂志

<p><b>OBJECTIVE</b>To discuss a new technique about reconstruction of medial collateral ligament (MCL) with double bundle allograft and to evaluate the short-term clinical efficacy.</p><p><b>METHODS</b>All 53 patients who suffered from valgus instability of the knee were selected. All cases were diagnosed of MCL injury because the medial gap of the knee widened more than 5 mm compared with collateral knee by the stress X-ray, MRI displayed discontinuity of MCL and valgus stress test was positive. All patients were accepted arthroscopic evaluation through inferomedial and inferolateral arthroscopy portal incisions to ascertain whether there were intra-articular injuries. An 8 cm incision was made from 1 cm superior adductor tubercle to 5 cm proximal medial tibia joint line in a longitudinal fashion. The anterior tibia insertion was defined as 15 mm lateral from the medial tibia edge and 45 mm under the medial tibia joint line. The posterior tibia insertion was defined as 15 mm lateral from the medial tibia edge and 20 mm under the medial tibia joint line. We used 5 mm or 6 mm reamer to drill the tibia tunnel along with guide pin, and then drill the femur tunnel with 6 mm or 7 mm drill in the top of the adductor tubercle about 25 mm or 30 mm length. The allograft was pulled into the tunnel from tibia to the femur and fixed with absorbable interference screw. Patients carried out active rehabilitation program after operation. One year after the operation, IKDC score, Lysholm score were used to evaluate the clinical effect.</p><p><b>RESULTS</b>The IKDC score (A or B, 86.78% vs. 0), Lysholm scores (89.7 ± 3.4 vs. 51.8 ± 4.9, t = -79.724, P < 0.05) were significantly improved compared with preoperative in all patients. Medial joint widened gap decreased from (10.4 ± 2.4) mm preoperative to (2.8 ± 1.5) mm postoperative from X ray and the differences were significant (t = 41.727, P < 0.05). Among these patients, the medial joint widened gap of 46 cases were less than 3 mm, 7 cases were from 3 mm to 5 mm. The range of motion was 135.4° ± 2.5° preoperative and 132.7° ± 3.7° postoperative. The 9 patients still had medial tenderness 1 year after operation.</p><p><b>CONCLUSION</b>Application double bundle allograft technique to reconstruct MCL can significantly improve the stability of the knee and the short-term clinical efficacy was sure.</p>

Comparison of mini-probe endoscopic ultrasonography with computed tomography in preoperative staging of esophageal cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To compare mini-probe endoscopic ultrasonography (MCUS) with computed tomography (CT) in preoperative T and N staging of esophageal cancer, and to find out the MCUS parameters to judge lymph node metastasis for esophageal cancer.</p><p><b>METHODS</b>Thirty-five patients received both MCUS and CT preoperatively, on both of which the T and N stages were determined. The accuracy, sensitivity, specificity, positive predicting value and negative predicting value were compared with the postoperative pathological results.</p><p><b>RESULTS</b>The accuracy of MCUS was 85.7% in T staging and 85.7% and 80.0% in N staging by the two different methods, which were 45.7% and 74.3%, respectively, by CT.</p><p><b>CONCLUSION</b>MCUS is better than CT in preoperative staging for esophageal cancer. The ratio of short to long axis (S/L) combined with short axis is a useful way to determine lymph node metastasis.</p>