An Iterative Deconvolution-Time Reversal Method with Noise Reduction, a High Resolution and Sidelobe Suppression for Active Sonar in Shallow Water Environments.

Matched filtering is widely used in active sonar because of its simplicity and ease of implementation. However, the resolution performance generally depends on the transmitted waveform. Moreover, its detection performance is limited by the high-level sidelobes and seriously degraded in a shallow water environment due to time spread induced by multipath propagation. This paper proposed a method named iterative deconvolution-time reversal (ID-TR), on which the energy of the cross-ambiguity function is modeled, as a convolution of the energy of the auto-ambiguity function of the transmitted signal with the generalized target reflectivity density. Similarly, the generalized target reflectivity density is a convolution of the spread function of channel with the reflectivity density of target as well. The ambiguity caused by the transmitted signal and the spread function of channel are removed by Richardson-Lucy iterative deconvolution and the time reversal processing, respectively. Moreover, this is a special case of the Richardson-Lucy algorithm that the blur function is one-dimensional and time-invariant. Therefore, the iteration deconvolution is actually implemented by the iterative temporal time reversal processing. Due to the iterative time reversal method can focus more and more energy on the strongest target with the iterative number increasing and then the peak-signal power increases, the simulated result shows that the noise reduction can achieve 250 dB in the "ideal" free field environment and 100 dB in a strong multipaths waveguide environment if a 1-ms linear frequency modulation with a 4-kHz frequency bandwidth is transmitted and the number of iteration is 10. Moreover, the range resolution is approximately a delta function. The results of the experiment in a tank show that the noise level is suppressed by more than 70 dB and the reverberation level is suppressed by 3 dB in the case of a single target and the iteration number being 8.

Rapid analysis of short- and medium-chain chlorinated paraffins in wine by dispersive liquid-liquid micro-extraction coupled with high performance liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry.

This study established a simple and rapid method for determination of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) by dispersive liquid-liquid micro-extraction coupled with high performance liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-Q-TOF/MS) in white and red wines. Affecting variables, including extraction solvent, salt concentration, ultrasound-vortex conditions and ethanol content, were evaluated. Under optimized conditions, the limit of detection (LODs) for SCCPs and MCCPs were in the range of 0.15-3.00 ng mL-1 and 0.08-2.50 ng mL-1, respectively. The spiked recoveries of SCCPs and MCCPs from white and red wine ranged from 63.2% to 127%. The method is precise with intra- and inter-day variations within 14.0% and 17.0%, respectively. SCCPs and MCCPs in wines from china varied widely, from

Development a simple and rapid HPLC-ESI-Q-TOF/MS method for determination of short- and medium- chain chlorinated paraffins in human serum.

This study established a simple and rapid method for simultaneous determination of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in human serum by high performance liquid chromatography coupled with electron spray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-Q-TOF/MS). A simple pretreatment procedure of protein precipitation by acetonitrile coupled with liquid-liquid extraction by n-hexane was employed for extraction and purification. The purified samples were separated by a PFP chromatographic column. This method could effectively eliminate the matrix effect by lipids and other matrix substances in serum samples with less time and solvent consuming. 76 congener groups of SCCPs and MCCPs with C10-C17 and Cl5-Cl13 were quantified by their [M-H]- ions. Method detection limit (MDL) were 1.0-8.0 ng mL-1 for ∑SCCPs and ∑MCCPs. Recoveries were 98.4 ±â€¯4.42%, 98.8 ±â€¯3.96% and 90.7 ±â€¯2.79% for SCCPs and 93.1 ±â€¯6.67%, 108 ±â€¯1.21% and 90.8 ±â€¯3.78% for MCCPs at spiking concentrations of 20, 50 and 200 ng·mL-1, respectively. The relative standard deviations (RSDs) of intra- and inter-day variations were 1.41% and 9.84% for SCCPs, and 4.23% and 6.26% for MCCPs. The suitability of the developed method was demonstrated through the application to analysis of SCCPs and MCCPs in human serum samples.

Short-term outcomes after transition from Sweet to thoracoscopic esophagectomy: Our experience and cost analysis.

OBJECTIVE: Thoracoscopic esophagectomy (TSE), as a minimally invasive technique, has obtained wide acceptance for treating esophageal cancer. In this study, we report our experience of the transfer from open sweet esophagectomy (OSE) to TSE and compare cost associated with the two approaches for esophageal cancer. PATIENTS AND METHODS: Data were taken through a retrospective review of operative outcomes, complications and cost of 91 patients who underwent OSE or TSE for esophageal cancer from January 2012 to June 2014. RESULTS: Among 91 patients, 48 patients underwent TSE, and 43 patients underwent OSE. Patients dealt with TSE had significantly less blood loss (152 ml vs. 204 ml, P = 0.004), shorter chest drainage time (3.3 days vs. 4.5 days, P < 0.001), less patients admitted to the Intensive Care Unit after surgery (6.3% vs. 30.2%, P = 0.003), and lower incidence of respiratory complications (16.7% vs. 37.2%, P = 0.026). However, the operative time was statistically longer in TSE group (276.0 min vs. 207.4 min, P < 0.001). The total cost (¥61,817 vs. ¥48,712, P < 0.001) and the day of surgery cost (¥29,701 vs. ¥19,446, P < 0.001) were significantly higher in the TSE group. CONCLUSION: This study shows that TSE is a safe and acceptable alternative to OSE. TSE will be more competitive if its cost can be reduced.

Expression and role of H-type vessels in the subchondral bone in the progression of osteoarthritis / 中国组织工程研究

BACKGROUND: H-type vessels are mainly distributed in the metaphysis, which can promote the proliferation of osteocytes, further accelerating osteogenesis.OBJECTIVE: To investigate the expression of H-type vessels in the subchondral bone during the occurrence and development of osteoarthritis.METHODS: 8-week-old C57 mice were randomly divided into experimental and sham groups, followed by the right medial menisectomy to establish the osteoarthritis models or only articular capsulotomy. The knee samples were removed at 4 weeks postoperatively, and were stained with safranin-O-fast green to evaluate the degree of injury. The expression levels of CD31, Emcn and matrix metalloproteinase 13 were detected by immunofluorescent staining. The changes of the subchondral bone were observed by hematoxylin-eosin staining and the changes of bone mass in the subchondral bone were analyzed by micro-CT.RESULTS AND CONCLUSION: Compared with the sham group, the Osteoarthritis Research Society International scores, expression levels of CD31, Emcn, H-type vessels and matrix metalloproteinase 13, as well as the bone mass in the subchondral bone were significantly increased in the experimental group (P < 0.05). To conclude, the increased H-type vessels in the subchondral bone promote the hyperplasia and remodeling of subchondral bone in the progression of osteoarthritis.

Baseline Susceptibility of Plutella xylostella (Lepidoptera: Plutellidae) to the Novel Insecticide Spinetoram in China.

Spinetoram is a spinosyn, which is a unique class of natural insecticide. Because of its novel mode of action, spinetoram is more potent and faster acting than other insecticides, even the older spinosyn product, spinosad. On account of being efficient on insect order Lepidoptera, spinetoram provides a new alternative for control of Plutella xylostella (L.) (Lepidoptera: Plutellidae), which are resistant to other chemicals. To determine the current situation of resistance of P. xylostella to spinetoram, the susceptibility of 16 P. xylostella populations from different regions of China or different time in addition to the population from laboratory was assessed using a leaf dip bioassay. The variation in spinetoram susceptibility among the 16 field populations was narrow, with median lethal concentrations (LC50 values) ranging from 0.131 to 1.001 mg/liter. Toxicity ratios (TRs) ranged from 1.5 to 7.6 and were 5.6 and 7.6 for populations SY-2 and FX-1, respectively, indicating some low level of tolerance in these populations. A discriminating concentration (a concentration that can detect the occurrence of resistance in a population) of 10 mg/liter, which was identified based on the pooled toxicological data, caused 100% mortality in all nine tested populations. The baseline susceptibility data reflect the natural variation of the P. xylostella populations to spinetoram rather than variation caused by previous exposure.

Theoretical mechanism for selective catalysis of double hydrophosphination of terminal arylacetylenes by an iron complex.

The detailed mechanism of the double hydrophosphination of terminal arylacetylenes catalyzed by an iron complex was studied by density functional theory. The calculated results suggest that the reaction proceeds in three steps: active species generation, single hydrophosphination reaction (Cycle 1), double hydrophosphination reaction, viz., active species regeneration (Cycle 2). The results uncovered the selectivity of the iron complex for double hydrophosphination of terminal arylacetylenes. The symmetry of frontier molecular orbitals determines the effectiveness of the catalyst. We also discuss the formation mechanism of the single hydrophosphination product with Z configuration.