Two-dimensional self-assembly of diacetylenic acid derivatives and their light-induced polymerization on HOPG surfaces.

The bottom-up fabrication of molecular nanodevices will require precise (photo)-control over self-assembled interfacial structures. Here, the self-assembly and photopolymerization behaviors of six diacetylenic acid derivatives on highly oriented pyrolytic graphite (HOPG) surfaces are studied by using scanning tunneling microscope (STM). The van der Waals interaction among alkyl chains is the predominant driving force for determining the varied assembly structure. Diacetylenic acid derivatives with the diacetylene moiety directly connected to the carboxyl group (2,4-heptadecadiynoic acid (C17H26O2), 2,4-nonadecadiynoic acid (C19H30O2) and 2,4-heneicosadiynoic acid (C21H34O2)) assemble to form surface monolayers with lamella-like structures where the alkyl chains interdigitate. Moreover, diacetylenic acid derivatives with the diacetylene group located in the middle of the side chains and far from the carboxyl group (10,12-tricosadiynoic acid (C23H38O2), 10,12-pentacosadiynoic acid (C25H42O2) and 10,12-heptacosadiynoic acid (C27H46O2)) tend to assemble into paralleled structures with the alkyl chains adopting a tail-to-tail assembly mode. This work thus elucidates in detail the structure-function relationships for photo-modifiable self-assembled interfacial nanostructures based on diacetylenic acid.

[Clinical application of modified minimally cardiopulmonary bypass: compared with conventional cardiopulmonary bypass].

OBJECTIVE: To evaluate the safety and effects on blood transfusion of modified minimally cardiopulmonary bypass (CPB). METHODS: From April 2013 to February 2016, 1 103 elective cardiac surgery cases in National Center for Cardiovascular Diseases China, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College were prospectively enrolled in the study. Patients undergoing modified minimally CPB were assigned to mini-CPB group (n=553), the others undergoing conventional CPB were assigned to conventional group (n=550). In mini-CPB group, oxygenator with integrated arterial filter, modified minimized circuit, mini-cardioplegia and vacuum assisted venous drainage(VAVD) were used. In conventional group, conventional CPB was composed with conventional oxygenator from the same manufactory, conventional circuit and 1∶4 blood cardioplegia. Analysis was performed with t test, t' test, Wilcoxon rank-sum test, χ(2) test, and Fisher exact test. RESULTS: No CPB accidents and peri-operative stroke were observed. There was no statistical difference in postoperative mechanical ventilation time, length of ICU stay, postoperative complications and mortality between the two groups. The incidence of erythrocyte transfusion (13.7% vs. 27.6%, χ(2)=32.458, P=0.000) and the incidence of ultrafilter (11.0% vs. 33.7%, χ(2)=76.019, P=0.000) were lower in the mini-CPB group. Postoperative hematocrit (M(QR): 32.9 (5.7) vs. 32.2 (5.7), Z=3.403, P=0.001) and 12-hour chest drainage ((228±154) ml vs.(260±197) ml, t'=3.004, P=0.003) of mini-CPB were imporved compared with conventional group. CONCLUSIONS: Modified minimally CPB is safe. It might reduce erythrocyte transfusion for adult cardiac surgery, warranting widely adoption.

Emerging Yr26-Virulent Races of Puccinia striiformis f. tritici Are Threatening Wheat Production in the Sichuan Basin, China.

Stripe rust, caused by Puccinia striiformis f. tritici, is one of the most destructive diseases of wheat in the world. The Sichuan Basin is one of the most important regions of wheat production and stripe rust epidemics in China. Stripe rust resistance gene Yr26 (the same gene as Yr24) has been widely used in wheat breeding programs and in many cultivars grown in this region since the gene was discovered in the early 1990s. Virulence to Yr26 has increased in frequency since its first detection in 2008. The objective of this study was to assess the vulnerability of the wheat cultivars and breeding lines in the Sichuan Basin to Yr26-virulent races. In total, 85 wheat accessions were tested with Yr26-avirulent races CYR32, CYR33, and Su11-4 and two Yr26-virulent races, V26/CM42 and V26/Gui22. DNA markers for Yr26 were used to determine the presence and absence of Yr26 in the wheat accessions. Of the 85 wheat accessions, only 5 were resistant and 19 susceptible to all races tested, and the remaining 61 were resistant to at least one or more races tested in seedling stage. In all, 65 (76.5%) accessions were susceptible to the emerging Yr26-virulent race V26/Gui22. In field tests, susceptible accessions increased from 31.8% in a nursery inoculated with predominant and Yr26-avirulent races to 61.2% in the nursery inoculated with the predominant races mixed with V26/Gui22. Based on the results of the molecular marker and race tests, 33 (38.8%) accessions were determined to have Yr26, showing that the Yr26 virulence is a major threat to wheat production in the Sichuan Basin and potentially in other regions of China.

Accuracy improvement on polymer identification using laser-induced breakdown spectroscopy with adjusting spectral weightings.

A new approach to polymer identification by laser-induced breakdown spectroscopy (LIBS) with adjusting spectral weightings (ASW) was developed in this work aiming at improving the identification accuracy. This approach has been achieved through increasing the intensities of specific characteristic spectral lines which are important to polymer identification but difficult to be excited. Using the ASW method, the identification accuracies of all 11 polymers were increased to nearly 100%, while the accuracies of PE, PU, PP and PC were only 98%, 74%, 90% and 98%, respectively, without using the ASW method.

Accuracy improvement of quantitative analysis in laser-induced breakdown spectroscopy using modified wavelet transform.

A modified algorithm of background removal based on wavelet transform was developed for spectrum correction in laser-induced breakdown spectroscopy (LIBS). The optimal type of wavelet function, decomposition level and scaling factor γ were determined by the root-mean-square error of calibration (RMSEC) of the univariate regression model of the analysis element, which is considered as the optimization criteria. After background removal by this modified algorithm with RMSEC, the root-mean-square error of cross-validation (RMSECV) and the average relative error (ARE) criteria, the accuracy of quantitative analysis on chromium (Cr), vanadium (V), cuprum (Cu), and manganese (Mn) in the low alloy steel was all improved significantly. The results demonstrated that the algorithm developed is an effective pretreatment method in LIBS to significantly improve the accuracy in the quantitative analysis.