Derivation and validation of a novel preoperative risk prediction model for surgical site infection in pancreaticoduodenectomy and comparison of preoperative antibiotics with different risk stratifications in retrospective cohort.

BACKGROUND: Surgical site infections (SSIs) are common postoperative complications of pancreaticoduodenectomy. AIM: To develop a model for preoperative identification of the risk of SSI that may improve outcomes and guide preoperative antibiotics. METHODS: The prediction model was built by meta-analysis. After literature search and inclusion, data extraction, and quantitative synthesis, the prediction model was established based on the pooled odds ratio of predictors. A single-centre retrospective cohort was the validation cohort. Receiver operating characteristic curves and area under the curve were used to assess the model's ability. We also created a decision curve and a calibration plot to assess the nomogram. The effects of prophylactic antibiotics on SSI were compared between groups by multivariable logistic regression with different risk stratifications. FINDINGS: Twenty-eight studies were included in the meta-analysis, 17 studies in the derivation cohort. Age, male gender, body mass index, pancreatic duct diameter, high-risk diagnosis, and preoperative biliary drainage were selected to build the prediction model. The model was validated in an external cohort. The cut-off value was 3.5 and area under the curve (AUC) was 0.76 in open pancreaticoduodenectomy (OPD). In laparoscopic pancreaticoduodenectomy, the cut-off value was 4.5 and AUC was 0.69. Decision curve and calibration plot showed good usability of the model, especially in OPD. Multivariable logistic regression did not indicate differences between broad- and narrow-spectrum antibiotics for SSI in different risk stratifications. CONCLUSION: The model can identify patients with a high risk of SSI preoperatively. The choice of prophylactic antibiotics under different risk stratifications should be investigated further.

[Clinical study of S-1 single agent adjuvant chemotherapy in the radical resection of extrahepatic biliary carcinoma].

Objective: To explore the clinical efficacy of S-1 single agent adjuvant chemotherapy for the patients undergoing radical resection of extrahepatic biliary carcinoma. Methods: The clinical data of 108 patients with extrahepatic biliary carcinoma receiving radical resection who were admitted from January 2014 to June 2017 were retrospectively analyzed. There were 62 males(57.4%)and 46 females(42.6%),with a median age of 59 years (range:26 to 79 years),10 cases(9.3%) in stage Ⅱ,85 cases(78.7%) in stage Ⅲ, and 13 cases (12.0%) in stage Ⅳ, 40 cases(37.0%) of hilar cholangiocarcinoma, 8 cases(7.4%) of middle cholangiocarcinoma, 25 cases (23.2%) of distal cholangiocarcinoma, 35 cases(32.4%) of gallbladder carcinoma.After radical resection of extrahepatic biliary carcinoma, 49 patients receiving S-1 single agent chemotherapy and 59 patients receiving non-special treatment were divided into the chemotherapy group and the operation group,respectively. All the dates of the patients were followed up and collected with the overall survival time,tumor-free survival time,1,2 and 3-year survival rate after operation,and the rate of major toxic reaction during chemotherapy of the chemotherapy group. Survival curve was drawn by the Kaplan-Meier method, and survival analysis was done using the Log-rank test. Results: There were no significant differences in the general date of two groups(sex, age, tumor size, tumor site, TNM stages, degree of differentiation). The median overall survival time and the median tumor-free survival time in the chemotherapy group were 27 months and 21 months,respectively,and in the operation group were 21 months and 17 months,respectively. There were differences between the two groups in the overall survival rates(χ(2)=3.967,P<0.05) and the 2 and 3-year survival rate(63.3%,36.6%;41.6%,20.4%;χ(2)=4.510,P<0.05;χ(2)=6.143,P<0.05),but the 1-year overall survival rate (83.4%,79.7%)was not statistically significant(χ(2)=0.286,P>0.05). There were no significant differences in the tumor-free survival time,1,2 and 3-year tumor-free survival rate(77.6%,41.4%,33.1%;62.7%,30.9%,21.2%)between the two groups(χ(2)=0.876,P>0.05;χ(2)=0.252,P>0.05;χ(2)=1.571,P>0.05;χ(2)=3.323,P>0.05,respectively). The main toxic reaction during chemotherapy were dyspepsia(28.6%, 14/49), anemia(26.5%, 13/49), and leukopenia(22.5%, 11/49), all of which were mild. Conclusion: S-1 single agent chemotherapy after radical reseetion of extrahepatic biliary carcinoma could effectly improve the survival of patients and all of the main toxic reaction during chemotherapy were mild.

Acoustic directional source based on Penrose quasi-crystal arrangements of metallic rods embedded in a fluid.

The directional emission properties of a circular device formed of a small number of metallic rods placed at the nodes of Penrose's tiling are investigated. At the center of the device a non-directional primary source emits monochromatic acoustic waves. In a wide frequency range, the beams come out of the device along preferential directions related to the symmetry of order 5 of the tiling and the non-periodicity in the radial direction. There are some frequencies for which the waves are completely trapped by the device. The shape, the distribution and the intensity of the emitted beams outside are closely dependent on the frequency. A comparison between numerical results and experiments is presented.

Effects of periodicity perturbations on the transmission by underwater phononic crystals.

The effects of periodicity perturbations in underwater phononic crystal layers composed of noninterpenetrating rows of identical shells are investigated. The results for one row are obtained by using a multiple scattering method between shells. Then, taking into account the multiple reflections and transmissions between two adjacent rows, a Debye series method is used to calculate the reflection and transmission coefficients by a finite number of rows. The paper focuses on three kinds of perturbations: (i) variation of the inner radius of shells from row to row, (ii) increase in the spacing from row to row and of the number of rows, and (iii) substitution of simple steel rows by steel-polyethylene bilayers. It is shown by studying the transmission coefficient that the case (i) permits the insertion of narrow pass bands in the stop band while the two other cases (ii) and (iii) widen the stop band. The study intends to model simple underwater acoustic filters.

3,4-Alkylenedioxypyrroles: functionalized derivatives as monomers for new electron-rich conducting and electroactive polymers.

New functionalized derivatives of 3,4-ethylenedioxypyrrole (EDOP, 5a) and 3,4-(1,3-propylenedioxy)pyrrole (ProDOP, 5b) as especially electron-rich monomers which yield highly electroactive and stable conducting polymers useful for a diverse set of applications have been synthesized. N-Alkylations of ProDOP were carried out to yield a variety of ProDOP derivatives having alkyl, sulfonatoalkoxy, glyme, and glyme alcohol pendant chains. Iodization of EDOP and ProDOP via iodo-decarboxylation afforded iodo-functionalized derivatives useful for subsequent aryl coupling chemistry. N-Protection and formylation of EDOP, followed by Knoevenagel condensation of the resultant 2-formyl-EDOP with aryl acetonitrile derivatives, led to 1-cyano-2-(2-(3,4-ethylenedioxypyrryl))-1-(2-thienyl)vinylene (23) (Th-CNV-EDOP) and 1-cyano-2-(2-(3,4-ethylenedioxypyrryl))-1-(2-(3,4-ethylenedioxythienyl)vinylene (26) (EDOT-CNV-EDOP). A 14-crown-4-ether 34 based dioxypyrrole was synthesized with a cavity potentially useful for lithium ion coordination and sensing in the resultant electroactive polymer. C-Alkylated ProDOPs (43a, 43b, and 43c) containing octyl, ethylhexyl, and dioctyl substituents appended to the central methylene of the propylene bridge, were prepared as monomers for potentially soluble pi-conjugated polymers.