Characterization of two novel hydrolases from Sphingopyxis sp. DBS4 for enantioselective degradation of chiral herbicide diclofop-methyl.

Diclofop-methyl, an aryloxyphenoxypropionate (AOPP) herbicide, is a chiral compound with two enantiomers. Microbial detoxification and degradation of various enantiomers is garnering immense research attention. However, enantioselective catabolism of diclofop-methyl has been rarely explored, especially at the molecular level. This study cloned two novel hydrolase genes (dcmA and dcmH) in Sphingopyxis sp. DBS4, and characterized them for diclofop-methyl degradation. DcmA, a member of the amidase superfamily, exhibits 26.1-45.9% identity with functional amidases. Conversely, DcmH corresponded to the DUF3089 domain-containing protein family (a family with unknown function), sharing no significant similarity with other biochemically characterized proteins. DcmA exhibited a broad spectrum of substrates, with preferential hydrolyzation of (R)-(+)-diclofop-methyl, (R)-(+)-quizalofop-ethyl, and (R)-(+)-haloxyfop-methyl. DcmH also preferred (R)-(+)-quizalofop-ethyl and (R)-(+)-haloxyfop-methyl degradation while displaying no apparent enantioselective activity towards diclofop-methyl. Using site-directed mutagenesis and molecular docking, it was determined that Ser175 was the fundamental residue influencing DcmA's activity against the two enantiomers of diclofop-methyl. For the degradation of AOPP herbicides, DcmA is an enantioselective amidase that has never been reported in research. This study provided novel hydrolyzing enzyme resources for the remediation of diclofop-methyl in the environment and deepened the understanding of enantioselective degradation of chiral AOPP herbicides mediated by microbes.

Damping Properties of Selective Laser-Melted Medium Manganese Mn-xCu Alloy.

In this work, selective laser melting (SLM) technology was applied to directly realize the in situ synthesis of medium manganese Mn-xCu (x = 30-40 wt.%) alloys based on the blended elemental powders. The effects of heat treatment on the microstructural evolution and damping properties of the SLMed Mn-xCu alloys were investigated. The metastable miscibility gap was studied by thermodynamic modeling and microhardness measurement. The results showed that γ-(Mn, Cu) phase with dendritic arm spacing (DAS) of 0.9-1.2 µm was the main constituent phase in the as-SLMed alloys, which was one to two orders of magnitude finer than those of the as-cast samples. Aging at 400-480°C for the Mn-30%Cu or 430°C for Mn-40%Cu alloys can induce spinodal decomposition, martensitic transformation, and α-phase precipitation, whose direct evidence was provided for the first time by transmission electron microscopy and 3D atom probe tomography in the work. The miscibility gap obtained from thermodynamics calculation was basically consistent with the microhardness results for the SLMed Mn-xCu alloys. Solution and aging (SA) treatment can improve the microstructure, tensile and damping properties of the SLMed Mn-xCu alloys more obviously than aging treatment. A 2.3-2.8 and 4.3-4.5 times increase was produced in damping capacity in the aged SLMed and SLMed+SAed Mn-xCu samples, respectively.

Determination of C═C Positions of Unsaturated Fatty Acids in Foods via Ambient Reactive Desorption Ionization with Water Dimer Radical Cations.

The positions of C═C bonds in unsaturated fatty acids (FAs) are one of the main factors determining the quality of food flavor. Herein, we developed an approach for the determination of C═C bonds of FAs by online epoxidation reaction with water dimer radical cations. The limit of detection for octenoic acid isomers was ∼9 µg/L. The positions of C═C bonds in trans-2/3-hexenoic acid, trans-2/3-octenoic acid, oleic acid, linoleic acid, and linolenic acid in black tea or olive oil samples were directly determined by the established method. These results indicate that the established method allows the rapid determination of unsaturated FAs in black tea and olive oil. The advantages of this approach include the analysis speed (∼1 min per sample), simple device, and no need for complex pretreatment. This study not only provides a strategy for the determination of C═C positions but also offers new possibilities for applications in the field of food chemistry.

Dahl Friction Model for Driving Characteristics of V-Shape Linear Ultrasonic Motors.

The contact process of stator and slider described by the Coulomb friction model is basically in a pure sliding friction state, and a mechanical model based on the Dahl friction theory was proposed to describe the contact process between stator and slider of V-shape linear ultrasonic motor. With consideration for the tangential compliance of stator and slider, the dynamic contact and friction processes of stator and slider were addressed in stages. The simulation results show that the ratio of the friction positive work decreases with the increase of the preload, and the vibration amplitude of the stator increases the proportion of positive work of the friction force. Improving the contact stiffness of the stator and slider is conducive to improving the output performance of the ultrasonic motor. The asymmetry of the left and right performance of the V-shaped vibrator will cause a difference in the left and right running speeds of the ultrasonic motor. The improved Dahl friction-driving model makes up for the discontinuity of tangential contact force calculated by the Coulomb friction model. This study demonstrates that the friction-driving model based on the Dahl theory is reliable and reasonable for linear ultrasonic motors according to the experimental results.

Sleep EEG characteristics associated with total sleep time misperception in young adults: an exploratory study.

BACKGROUND: Power spectral analysis (PSA) is one of the most commonly-used EEG markers of cortical hyperarousal, and can help to understand subjective-objective sleep discrepancy (SOD). Age is associated with decreased sleep EEG activity; however, the PSA of young adults is currently limited. Thus, this study aimed to examine the correlation of spectral EEG power with total sleep time (TST) misperception in young patients. METHODS: Forty-seven young adults were recruited and underwent a polysomnography recording in a sleep laboratory. Clinical records and self-report questionnaires of all patients were collected, and were used to categorize patients into a good sleeper (GS) group (n = 10), insomnia with a low mismatch group (IWLM, n = 19) or participant with a high mismatch group (IWHM, n = 18). PSA was applied to the first 6 h of sleep. RESULTS: IWHM patients exhibited a higher absolute power and relative beta/delta ratio in the frontal region compared to the GS group. No significant difference was observed between the IWLM and GS groups. No significant difference in the above parameters was observed between the IWHM and IWLM groups. Moreover, The SOD of TST was positively correlated with frontal absolute power and the relative beta/delta ratio (r = 0.363, P = 0.012; r = 0.363, P = 0.012), and absolute beta EEG spectral power (r = 0.313, P = 0.032) as well as the number of arousals. CONCLUSIONS: Increased frontal beta/delta ratio EEG power was found in young patients with a high mismatch but not in those with a low mismatch, compared with good sleepers. This suggests that there exists increased cortical activity in IWHM patients. In addition, the frontal beta/delta ratio and the number of arousals was positively correlated with the SOD of TST.

Green Tea Consumption and Esophageal Cancer Risk: A Meta-analysis.

Background: The protective role of green tea against cancer is still unknown.Objectives: To investigate the association between green tea consumption and esophageal cancer risk through meta-analysis.Methods: We searched MEDLINE, EMBASE, Web of Science and Cochrane Library for studies on the relationship between green tea and esophageal cancer risk. We assessed heterogeneity (I2) and publication bias (Begg's and Egger's tests). Pooled relative risks (RRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random effects models.Results: A total of 20 studies were included. The RRs for all studies was 0.65 (95% CI: 0.57-0.73), with I2 = 75.3% and P = 0. In the subgroup analysis, the following variables showed marked heterogeneity: Asian (RR: 0.64; 95% CI: 0.56-0.73) and non-Asian countries (RR: 0.74; 95% CI: 0.45-1.03), female (RR: 0.55; 95% CI: 0.39-0.71) and male + female (RR: 0.64; 95% CI: 0.54-0.75), case-control study (RR: 0.62; 95% CI: 0.52-0.71), impact factor >3 (RR: 0.65; 95% CI: 0.56-0.75), impact factor <3 (RR: 0.64; 95% CI: 0.48-0.80), Newcastle-Ottawa Scale >7 (RR: 0.82; 95% CI: 0.66-0.97) and Newcastle-Ottawa Scale ≤7 (RR: 0.59; 95% CI: 0.49-0.68).Conclusion: Green tea consumption could be a protective factor for esophageal cancer.

The energy absorption and bearing capacity of light-weight bio-inspired structures produced by selective laser melting.

Sandwich structures are widely used in aviation and aerospace fields because they can absorb vast energy due to their excellent continuous compression behaviors. And in this work, the light-weight bio-inspired sandwich structure of titanium alloy was designed based on cybister elytra and produced by selective laser melting (SLM). The results show that bio-inspired structures can realize the light-weight effectively by increasing the core height. The specific and ultimate flatwise compressive strengths first increase and then decrease when core height increases. The load-displacement curves of bio-inspired structures during flatwise compression consists of elastic deformation, buffer and compaction zone. Comparatively, the edgewise compression lacks buffer zone. And the bio-inspired structure has an excellent flatwise comprehensive performance when its core height is 6 mm, whose peak flatwise compressive strength and specific volume energy absorption are 84.30 MPa, 101.30 MJ/m3, respectively. The specific ultimate strength of bio-inspired structures is optimized at the core height of 4 mm on the edgewise compression tests. And the fracture of the side arc damaged area shows an obviously ductile fracture and the panel and core of the middle area are brittle fracture in the flatwise compressive tests. Finally, The ANSYS simulation results are consistent with experimental results during the whole compressions, which will provide an accurate guidance in next researches.

Elevated peripheral blood B lymphocytes and CD3+CD4-CD8- T lymphocytes in patients with non-small cell lung cancer: A preliminary study on peripheral immune profile.

It has been established that the tumor microenvironment (TME) has a crucial role in enabling tumors to evade from host immune responses. Previous studies demonstrated that tumor cells are not only able to reshape immune milieu at the tumor site, but also exert systemic effects, which has been demonstrated to be important for metastasis. At present, how the peripheral immune environment change in the tumor-bearing host is unclear. The present study identified a number of changes in the proportions of lymphocyte subpopulations and the levels of cytokines in patients with NSCLC, which may provide a preliminary profile of the immune environment in the peripheral blood of patients harboring a tumor. These findings expand on the present knowledge on how tumors can alter the immune system to benefit its growth and metastasis, which may provide a potential novel strategy for immunotherapy.

[The Initial Experience of Video-assisted Thoracic Surgery Segmentectomy for Early Stage Lung Cancer].

BACKGROUND: Segmentectomy can retains more healthy lung tissue than lobectomy, but it remains controversial in oncology for early stage lung cancer. The aim of this study is to discuss the problems of video-assisted thoracic surgery (VATS) segmentectomy in early stage lung cancer, by analyzing the clinical and pathological data of 35 cases and reviewing the literature. METHODS: There were 35 patients who received segmentectomy by complete video-assisted thoracic surgery, from May 2013 to July 2017, in single operation group in the Third Hospital of Peking University. We analyzed the patient's clinical and pathological data, intraoperative and postoperative complications, lymph node number and metastasis its situation, and compared postoperative pathology and preoperative computed tomography (CT) imaging type. In 35 cases of segmentectomy, there were 11 males and 24 females, with an average age of 57.7 years old. The lesions located in the right upper lobe were 8 cases, in the right lower lobe were 8 cases, in the left upper lobe were 13 cases, in the left lower lobe were 6 cases. The mean maximum diameter of CT imaging was 12.7 mm, and the largest diameter of hilar and mediastinal lymph nodes was less than 10 mm. 23 of them were ground glass predominating and 12 were solid components predominating. RESULTS: All 35 cases were successfully completed VATS anatomical segmentectomy. The average operation time was 153 minutes, the amount of bleeding was 51 mL. There were 10 cases of air leakage after operation, all of which were not more than 3 days. There was contralateral atelectasis in 1 case, chylothorax in 1 case. The average length of hospitalization was 6.1 days. There was no other complications outpatient related to surgery, in 30 days after discharge. The pathological changes were as follow, 2 cases of metastatic tumor, 8 cases of benign lung disease and 25 cases of primary lung cancer. In the 25 cases of primary lung cancer, there were 14 cases of invasive lung adenocarcinoma (7 cases were groundglassopacity (GGO) predominating in CT imaging), 4 cases of micro-invasive adenocarcinoma (3 cases were GGO predominating in CT imaging), 6 cases of adenocarcinoma in situ (all were pure GGO in CT imaging), 1 case of lung squamous cell carcinoma (mainly composed of solid in CT imaging). An average of 7.2 lymph nodes were removed in 25 cases of lung cancer, and all lymph nodes had no metastasis. CONCLUSIONS: VATS anatomical segmentectomy is technically safe and reliable, and the indications for lung cancer need to be strictly controlled. Its advantages still need to be confirmed by prospective randomized controlled trials.

Initial experience of sleeve lobectomy under complete video-assisted thoracic surgery.

PURPOSE: Review the initial results of a single-center complete video-assisted thoracoscopic surgery (VATS) sleeve lobectomy and discuss the key procedure of this operation, in addition to its safety and feasibility. METHODS: Retrospectively analyze the perioperative data of 11 patients who accepted complete VATS sleeve lobectomy between May 2013 and Jun 2017 in Peking University Third Hospital, try to evaluate the safety of this procedure. All the patients were followed up and their oncological recurrence and metastasis were observed, and feasibility of VATS sleeve lobectomy for lung cancer was evaluated. RESULTS: All of the 11 cases underwent complete VATS sleeve lobectomy successfully and there is no conversion to thoracotomy. The mean operative time was 338 min (range from 243 to 511 min), the mean time of bronchial anastomotic was 63 min (range from 40 to 96 min), the mean blood loss was 205 mL (range from 50 to 400 mL), and the mean number of lymph nodes dissected is 22.1. There was no other complication except one patient suffered from high-risk pulmonary embolism, and no anastomotic leakage and stricture was found. The mean hospital stay postoperation was 8.7 days. The time of follow-up was between 2 and 38 months, only one out of the 11 cases died of bone metastasis, and the other 10 survived till now. One of these 10 patients had local recurrence 24 months after operation, and one suffered adenocarcinoma of esophageal-gastric junction at 15 months postoperation. The rest of eight patients all survived to June 2017 and no local recurrence and metastasis was found. The mean survival time was 14.8 months. CONCLUSION: Complete VATS sleeve lobectomy is a safe and feasible procedure, but the advantage of perioperative and long-term survival need prospective randomized controlled large sample trial to be confirmed.

Gastroprotective Effects of Astragaloside IV against Acute Gastric Lesion in Rats.

BACKGROUND: Protection of the gastric mucosa from acute lesions induced by various irritants is a pertinent issue in the field of critical care medicine. In this study, we investigated the gastroprotective effects of astragaloside IV on acute gastric lesions in rats under stressful conditions. METHODS: Rats were randomized into six groups. Group 1 and 2 received 10% Tween 80 (vehicle). Group 3 received 20 mg/kg of omeprazole, a proton pump inhibitor. Groups 4, 5 and 6 received astragaloside IV at concentration of 1, 10, and 50 mg/kg, respectively. As a means to induce gastric lesions, Groups 2-6 were subjected to water immersion and restraint stress for 12 hours after treatment. RESULTS: Our present studies show that compared to rats in group 2, treatment with 1 to 50 mg/kg astragaloside IV significantly decreased the size of gastric lesions, MDA, TNFα and MCP1 levels, in addition to normalizing gastric pH, gastric mucus and SOD levels (P<0.05). Histomorphological examination confirmed that treatment with astragaloside IV elicited a dosage-dependent protective effect on the gastric mucosa. Furthermore, pretreatment with astragaloside IV resulted in significant elevations in HSP70 and reduction in Bax, along with over-expression of PLCγ response level, which was further confirmed via immunohistochemical analysis. CONCLUSIONS: The acute gastric lesions induced are attenuated by pretreatment with astragaloside IV which is possibly due to the enhancing of the expression of HSP70 with concomitant antioxidant, anti-inflammatory and anti-apoptotic capacity.

[An ultra-high-pressure liquid chromatography/linear ion trap-Orbitrap mass spectrometry method coupled with a diagnostic fragment ions-searching-based strategy for rapid identification and characterization of chemical components in Polygonum cuspidatum].

A method for qualitative analysis of constituents in Polygonum cuspidatum by ultra-high-pressure liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometry (UHPLC-LTQ-Orbitrap MS) has been established. The methanol extract of Polygonum cuspidatumrn was separated on a Waters UPLC C18 column using acetonitrile-water (containing formic acid) eluting system and detected by LTQ-Orbitrap hybrid mass spectrometer in negative mode. The targeted components were further fragmented in LTQ and high accuracy data were acquired by Orbitrap MS. The summarized fragmentation pathways of typical reference components and a diagnostic fragment ions-searching-based strategy were used for detection and identification of the main phenolic components in Polygonum cuspidatum. Other clues such as nitrogen rule, even electron rule, degree of unsaturation rule and isotopic peak data were included for the structural elucidation as well. The whole analytical procedure was within 10 min and more than 30 components were identified or tentatively identified. This method is helpful for further phytochemical research and quality control on Polygonum cuspidatum and related preparations.

Theoretical study on the reaction mechanisms of CH3O- with O2(X3Σ(g)-) and O2(a1Δ(g)).

The detailed potential energy surfaces (PESs) of poorly understood ion-molecule reactions of CH(3)O(-) with O(2)(X(3)Σ(g)(-)) and O(2)(a(1)Δ(g)) are accounted for by the density functional theory and ab initio of QCISD and CCSD(T) (single-point) theoretical levels with 6-311++G(d,p) and 6-311++G(3df,2pd) basis sets for the first time. For the reaction of CH(3)O(-) with O(2)(X(3)Σ(g)(-)) ((3)R), it is shown that a hydrogen-bonded complex (3)1 is initially formed on the triplet PES, which is 1.8 kcal/mol above reactants (3)R at the CCSD(T)//QCISD level, from which all the products P(1)-P(8) can be generated. As to the reaction of CH(3)O(-) with O(2)(a(1)Δ(g)) ((1)R), it is found that the two energetically low-lying complexes of (1)1(-31.5 kcal/mol) and (1)2(-24.1 kcal/mol) are initiated on the singlet PES. Starting from them, a total of seven products may be possible, that is, besides P(1), P(2), P(3), P(4), and P(8), which are the same as on the triplet PES, there exist also another two products, P(9) and P(10). For both reactions, taking the thermodynamics and kinetics into consideration, the hydride-transfer species P(1)(CH(2)O + HO(2)(-)) should be the most favorable product followed by P(8)(e + CH(2)O + HO(2)), which is a secondary product of electron-detachment from P(1), and the generation of endothermic P(7)(17.7 kcal/mol) for the reaction of CH(3)O(-) with O(2)(X(3)Σ(g)(-)) is also possible at high temperature, whereas the remaining products are negligible. The measured branching ratio of products for CH(3)O(-) with O(2)(X(3)Σ(g)(-)) by Midey et al. is 0.85:0.15 for P(1) and P(8), and that of CH(3)O(-) with O(2)(a(1)Δ(g)) is 0.52:0.48 with more P(8), which can be rationalized by our theoretical results that P(8) on the triplet PES is 4.9 kcal/mol above (3)R, whereas both P(1) and P(8) on the singlet PES are very low-lying at 45.6 and 25.2 kcal/mol below (1)R energetically. The measured total reaction rate constant of CH(3)O(-) with O(2)(a(1)Δ(g)) is k = 6.9 × 10(-10) cm(3) s(-1) at 300 K, which is larger than that of k = 1.1 × 10(-12) cm(3) s(-1) for the reaction of CH(3)O(-) with O(2)(X(3)Σ(g)(-)). This is understandable because both P(1) and P(8) on the singlet PES can be generated barrierlessly, whereas to give all the products on the triplet PES has to pass the barrier of (3)1(1.8 kcal/mol) at the CCSD(T)//QCISD level. It is expected that the present theoretical study may be helpful for understanding the reaction mechanisms related to CH(3)O(-) and even CH(3)S(-).

[Modeling of acute respiratory distress syndrome in canine after inhalation of perfluoroisobutylene and preliminary study on mechanisms of injury].

OBJECTIVE: To establish of acute respiratory distress syndrome (ARDS) model in canine after inhalation of perfluoroisobutylene (PFIB), and to observe the progressing of lung injury, and to study the mechanisms of injury. METHODS: A device of inhalation of PFIB for canine was made. The concentration of PFIB was 0.30 - 0.32 mg/L. Serum IL-6 and IL-8 were dynamically measured. Clinical manifestations, pathology of organs in canine were observed. RESULTS: (1) During inhalation, the concentration of PFIB remained stable; (2) After inhalation, blood arterial oxygen partial pressure fell gradually, and eventually met the criteria for diagnosing ARDS; (3) The level of IL-8 in serum rises significantly after inhalation (P < 0.05), whereas that of IL-6 was not obviously altered (P > 0.05); (4) Within 6 hours after inhalation, no abnormality in canine was observed, but afterwards symptoms gradually appeared, and typical breath of ARDS, such as high frequency and lower level could be seen in later phase; (5) Pathological examination showed severe congestion, edema and atelectasis in most part of both lungs, and signs of anoxia in other organs. CONCLUSIONS: (1) The device designed is capable of ensuring control of inhalation of PFIB; (2) Exposure to PFIB for 30 mins, canines all met the criteria for diagnosing ARDS 22 hours after inhalation, therefore the modeling is successful; (3) PFIB specifically damages the lung by causing excessive inflammation.