Survival after minimally invasive radical hysterectomy with protective colpotomy for early-stage cervical cancer: A systematic review and meta-analysis.

Minimally invasive surgery on treatment of early-stage cervical cancer is debatable. Traditional approaches of colpotomy are considered responsible for an inferior oncological outcome. Evidence on whether protective colpotomy could optimize minimally invasive technique and improve prognoses of women with early-stage cervical cancer remains limited. We produced a systematic review and meta-analysis to compare oncological outcomes of the patients treated by minimally invasive radical hysterectomy with protective colpotomy to those treated by open surgery according to existing literature. We explored PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov from inception to December 2022. Inclusion criteria were: (1) randomized controlled trials or observational studies published in English, (2) studies comparing minimally invasive radical hysterectomy with protective colpotomy to abdominal radical hysterectomy in early-stage cervical cancer, and (3) studies comparing survival outcomes. Two reviewers performed the screening, data extraction, and quality assessment independently. A total of 8 retrospective cohort studies with 2020 women were included in the study, 821 of whom were in the minimally invasive surgery group, and 1199 of whom were in the open surgery group. The recurrence-free survival and overall survival in the minimally invasive surgery group were both similar to that in the open surgery group (pooled hazard ratio, 0.88 and 0.78, respectively; 95% confidence interval, 0.56-1.38 and 0.42-1.44, respectively). Minimally invasive radical hysterectomy with protective colpotomy on treatment of early-stage cervical cancer had similar recurrence-free survival and overall survival compared to abdominal radical hysterectomy. Protective colpotomy could be a guaranteed approach to modifying minimally invasive technique.

Mineral composition controls the stabilization of microbially derived carbon and nitrogen in soils: Insights from an isotope tracing model.

Evidence is emerging that microbial products and residues (necromass) contribute greatly to stable soil organic matter (SOM), which calls for the necessity of separating the microbial necromass from other SOM pools in models. However, the understanding on how microbial necromass stabilizes in soil, especially the mineral protection mechanisms, is still lacking. Here, we incubated 13 C- and 15 N-labelled microbial necromass in a series of artificial soils varying in clay minerals and metal oxides. We found the mineralization, adsorption and desorption rate constants of necromass nitrogen were higher than those of necromass carbon. The accumulation rates of necromass carbon and nitrogen in mineral-associated SOM were positively correlated with the specific surface area of clay minerals. Our results provide direct evidence for the protection role of mineral in microbial necromass stabilization and provide a platform for simulating microbial necromass separately in SOM models.

Detection of driver drowsiness level using a hybrid learning model based on ECG signals.

OBJECTIVES: Fatigue has a considerable impact on the driver's vehicle and even the driver's own operating ability. METHODS: An intelligent algorithm is proposed for the problem that it is difficult to classify the degree of drowsiness generated by the driver during the driving process. By studying the driver's electrocardiogram (ECG) during driving, two models were established to jointly classify the ECG signals as awake, stress, and fatigue or drowsiness states for drowsiness levels. Firstly, the deep learning method was used to establish the model_1 to predict the drowsiness of the original ECG, and model_2 was developed using the combination of principal component analysis (PCA) and weighted K-nearest neighbor (WKNN) algorithm to classify the heart rate variability characteristics. Then, the drowsiness prediction results of the two models were weighted according to certain rules, and the hybrid learning model combining dilated convolution and bidirectional long short-term memory network with PCA and WKNN algorithm was established, and the mixed model was denoted as DiCNN-BiLSTM and PCA-WKNN (DBPW). Finally, the validity of the DBPW model was verified by simulation of the public database. RESULTS: The experimental results show that the average accuracy, sensitivity and F1 score of the test model in the dataset containing multiple drivers are 98.79, 98.81, and 98.79 % respectively, and the recognition accuracy for drowsiness or drowsiness state is 99.33 %. CONCLUSIONS: Using the proposed algorithm, it is possible to identify driver anomalies and provide new ideas for the development of intelligent vehicles.

Integrating microbial community properties, biomass and necromass to predict cropland soil organic carbon.

Manipulating microorganisms to increase soil organic carbon (SOC) in croplands remains a challenge. Soil microbes are important drivers of SOC sequestration, especially via their necromass accumulation. However, microbial parameters are rarely used to predict cropland SOC stocks, possibly due to uncertainties regarding the relationships between microbial carbon pools, community properties and SOC. Herein we evaluated the microbial community properties (diversity and network complexity), microbial carbon pools (biomass and necromass carbon) and SOC in 468 cropland soils across northeast China. We found that not only microbial necromass carbon but also microbial community properties (diversity and network complexity) and biomass carbon were correlated with SOC. Microbial biomass carbon and diversity played more important role in predicting SOC for maize, while microbial network complexity was more important for rice. Models to predict SOC performed better when the microbial community and microbial carbon pools were included simultaneously. Taken together our results suggest that microbial carbon pools and community properties influence SOC accumulation in croplands, and management practices that improve these microbial parameters may increase cropland SOC levels.

Survival after minimally invasive radical hysterectomy without using uterine manipulator for early-stage cervical cancer: A systematic review and meta-analysis.

BACKGROUND: Minimally invasive radical hysterectomy has been reported to increase the risk of cancer relapse and death compared with open surgery in women with early-stage cervical cancer. The use of a uterine manipulator is considered one of the risk factors. OBJECTIVES: To investigate whether women with early-stage cervical cancer treated with minimally invasive radical hysterectomy without using uterine manipulator have oncological outcomes similar to those of open surgery. SEARCH STRATEGY: Searches were performed in MEDLINE, Embase and CENTRAL from their inception until 31 March 2022. SELECTION CRITERIA: Inclusion criteria were: (1) randomised controlled trials or observational cohort studies published in English, (2) studies comparing minimally invasive radical hysterectomy without using a uterine manipulator with open radical hysterectomy in women with early-stage cervical cancer, and (3) studies comparing survival outcomes. DATA COLLECTION AND ANALYSIS: Two authors independently conducted data extraction and assessed study quality. We calculated the hazard ratios (HR) and the 95% confidence intervals (CI) using the inverse variance approach for survival outcome. MAIN RESULTS: Six observational studies with 2150 women were included. The minimally invasive surgery group had a significantly higher risk of cancer relapse compared with open surgery group (HR 1.55, 95% CI 1.15-2.10). CONCLUSIONS: Minimally invasive radical hysterectomy without using a uterine manipulator resulted in an inferior recurrence-free survival compared with open radical hysterectomy in the treatment of women with early-stage cervical cancer.

Health-related quality of life measured by EQ-5D-3L for the spouses of breast cancer patients.

To explore factors influencing the health-related quality of life of spouses of breast cancer patients and the suitable questionnaires for this purpose. A cross-sectional study was conducted in the Third Affiliated Hospital of Kunming Medical University. The spouses of breast cancer patients were included and evaluated via face-to-face interviews. Self-designed demographic characteristics and disease-related questionnaires, the 12-item health survey questionnaire (SF-12), the three-level European five-dimensional health status scale (EQ-5D-3L), and the Social Support Rate Scale (SSRS) were used. The internal consistency reliability measure Cronbach's coefficient, criterion-related validity, construct validity, and sensitivity were used to evaluate the applicability of the EQ-5D-3L. Univariate and multivariate analyses were performed to analyze the factors associated with the health-related quality of life of spouses of breast cancer patients. We investigated a total of 100 spouses of breast cancer patients. Cronbach's α, the internal consistency reliability coefficient, was 0.502. The EQ-5D-3L health utility score was moderately correlated with PCS-12 (r=0.46, p=0.0001) and weakly correlated with MCS-12 (r=0.35, p=0.0001). The EQ-5D-3L health utility score for the spouses of breast cancer patients was 0.870, and the EQ-VAS was 78.3. In multivariate analysis, social support and cognition of the treatment effect were factors that influenced the EQ-5D-3L health utility score. The EQ-5D-3L has good reliability, validity, and sensitivity for measuring the physiological aspects of the health-related quality of life of spouses of BC patients. EQ-5D-3L was considered suitable for this study.

[Research on the detection algorithm of electrocardiogram characteristic wave based on energy segmentation and stationary wavelet transform].

The detection of electrocardiogram (ECG) characteristic wave is the basis of cardiovascular disease analysis and heart rate variability analysis. In order to solve the problems of low detection accuracy and poor real-time performance of ECG signal in the state of motion, this paper proposes a detection algorithm based on segmentation energy and stationary wavelet transform (SWT). Firstly, the energy of ECG signal is calculated by segmenting, and the energy candidate peak is obtained after moving average to detect QRS complex. Secondly, the QRS amplitude is set to zero and the fifth component of SWT is used to locate P wave and T wave. The experimental results show that compared with other algorithms, the algorithm in this paper has high accuracy in detecting QRS complex in different motion states. It only takes 0.22 s to detect QSR complex of a 30-minute ECG record, and the real-time performance is improved obviously. On the basis of QRS complex detection, the accuracy of P wave and T wave detection is higher than 95%. The results show that this method can improve the efficiency of ECG signal detection, and provide a new method for real-time ECG signal classification and cardiovascular disease diagnosis.

[Utilizing Academic Clubs to Foster Practical Research Ability of Medical Students-Volunteer Team of Gastric Cancer Surgery of West China Hospital, Sichuan University].

The cultivation of medical students'research ability promotes in them high-quality career development. In addition to classroom instruction of the theoretical knowledge concerning research, the systematic training and practice of scientific research skills outside the classroom is also vitally important. We established the Volunteer Team of Gastric Cancer Surgery with the features of standardization, progressiveness, and practicality in order to cultivate the thinking skills concerning research and the research ability of medical students. Our team is supported by the Department of Gastrointestinal Surgery, West China Hospital, Sichuan University. Taking clinical and basic research skills training as the focus of our work, we have organized systematic workshops focused on theoretical knowledge and research skills practice programs of divers forms. Our work helps improve the research ability of medical students, suggesting that research-oriented clubs play an active role in the cultivation of practical research ability of medical students and should be widely promoted.

The value of spleen-preserving lymphadenectomy in total gastrectomy for gastric and esophagogastric junctional adenocarcinomas: A long-term retrospective propensity score match study from a high-volume institution in China.

BACKGROUND: The benefit of removing the splenic lymph nodes in patients with proximal gastric cancer has been controversial. The purpose of our study was to investigate the importance of performing a splenic hilar lymph node dissection without splenectomy in patients undergoing total gastrectomy for gastric cancer. METHODS: From January 2006 to December 2015, we retrospectively reviewed patients who underwent a curative total gastrectomy for gastric cancer. Propensity score matching was used to balance any potential discrepancy of the other covariates between patients with and without splenic hilar lymph node dissection. Survival analysis, Cox univariate and multivariate analysis, and subgroups analysis were conducted to determine the value of splenic hilar lymph node dissection. After matching, 2 nomograms among patients with and without splenic hilar lymph node dissection were established respectively, the C-index, calibration curve and decision curve analysis were used to further evaluate the value of splenic hilar lymph node dissection. RESULTS: The rate of metastatic splenic hilar lymph nodes in the 274 patients undergoing splenic hilar lymph node dissection was 16.4% (45/274). Patients undergoing splenic hilar lymph node dissection had better survival outcomes than those not undergoing splenic hilar lymph node dissection before (P = .003) and after (P = .003) propensity score matching. Cox multivariate analysis also confirmed that splenic hilar lymph node dissection was an independent prognostic factor both before (hazard ratio 1.284, 95% confidence interval 1.042-1.583, P = .019) and after (hazard ratio 1.480, 95% confidence interval 1.156-1.894, P = .002) propensity score matching. Subgroup analysis indicted that splenic hilar lymph node dissection offered better survival outcomes for esophagogastric junctional adenocarcinoma (P < .001, P for interaction = .018). After propensity score matching, the nomogram of patients with splenic hilar lymph node dissection (C-index 0.735, 95% confidence interval 0.695-0.774) also indicated a statistically significant advantage compared with that without splenic hilar lymph node dissection (C-index 0.708, 95% confidence interval 0.668-0.748, P < .001). CONCLUSION: Our study suggests that spleen-preserving splenic hilar lymph node dissection should be an essential procedure among patients undergoing total gastrectomy.

Phosphorus Reduces Negative Effects of Nitrogen Addition on Soil Microbial Communities and Functions.

Increased soil nitrogen (N) from atmospheric N deposition could change microbial communities and functions. However, the underlying mechanisms and whether soil phosphorus (P) status are responsible for these changes still have not been well explained. Here, we investigated the effects of N and P additions on soil bacterial and fungal communities and predicted their functional compositions in a temperate forest. We found that N addition significantly decreased soil bacterial diversity in the organic (O) horizon, but tended to increase bacterial diversity in the mineral (A) horizon soil. P addition alone did not significantly change soil bacterial diversity but mitigated the negative effect of N addition on bacterial diversity in the O horizon. Neither N addition nor P addition significantly influenced soil fungal diversity. Changes in soil microbial community composition under N and P additions were mainly due to the shifts in soil pH and NO3- contents. N addition can affect bacterial functional potentials, such as ureolysis, N fixation, respiration, decomposition of organic matter processes, and fungal guilds, such as pathogen, saprotroph, and mycorrhizal fungi, by which more C probably was lost in O horizon soil under increased N deposition. However, P addition can alleviate or switch the effects of increased N deposition on the microbial functional potentials in O horizon soil and may even be a benefit for more C sequestration in A horizon soil. Our results highlight the different responses of microorganisms to N and P additions between O and A horizons and provides an important insight for predicting the changes in forest C storage status under increasing N deposition in the future.

The Role of HER2 in Self-Renewal, Invasion, and Tumorigenicity of Gastric Cancer Stem Cells.

BACKGROUND: Deregulation of HER2 expression could affect the biological characteristics of gastric cancer cells and treatment option for gastric cancer patients. This research aims to investigate the impact of HER2 on biological characteristics of gastric cancer stem cells (GCSCs) and prognosis of gastric cancer patients. METHODS: HER2 knockdown in GCSCs were constructed by lentivirus transfection. Alterations of proliferation, self-renewal, invasion, migration, colony formation, and tumorigenicity of GCSCs were examined. The changes of gene expressions after HER2 interference in GCSCs were detected by gene microarray. The impact of concentration of serum HER2 and expression of HER2 in tumor tissues on survival of 213 gastric cancer patients was also analyzed. RESULTS: Down-regulation of HER2 decreased the self-renewal, colony formation, migration, invasion, proliferation, and chemotherapy resistance of GCSCs. However, the tumorigenicity of GCSCs in vivo was increased after down-regulation of HER2. The results of gene microarray showed that HER2 gene might regulate the signal transduction of mTOR, Jak-STAT, and other signal pathways and affect the biological characteristics of GCSCs. Furthermore, survival analyses indicated that patients with high concentration of HER2 in serum had a favorable overall survival. However, there was no significant correlation between expression of HER2 in tumor tissue and overall survival. CONCLUSION: Interference of HER2 in GCSCs decreased the capacity of self-renewal, proliferation, colony formation, chemotherapy resistance, invasion, and migration but might increase the tumorigenicity in vivo. Patients with high concentration of HER2 in serum seemed to have a favorable prognosis.

Elevated temperature increases the accumulation of microbial necromass nitrogen in soil via increasing microbial turnover.

Microbial-derived nitrogen (N) is now recognized as an important source of soil organic N. However, the mechanisms that govern the production of microbial necromass N, its turnover, and stabilization in soil remain poorly understood. To assess the effects of elevated temperature on bacterial and fungal necromass N production, turnover, and stabilization, we incubated 15 N-labeled bacterial and fungal necromass under optimum moisture conditions at 10°C, 15°C, and 25°C. We developed a new 15 N tracing model to calculate the production and mineralization rates of necromass N. Our results showed that bacterial and fungal necromass N had similar mineralization rates, despite their contrasting chemistry. Most bacterial and fungal necromass 15 N was recovered in the mineral-associated organic matter fraction through microbial anabolism, suggesting that mineral association plays an important role in stabilizing necromass N in soil, independently of necromass chemistry. Elevated temperature significantly increased the accumulation of necromass N in soil, due to the relatively higher microbial turnover and production of necromass N with increasing temperature than the increases in microbial necromass N mineralization. In conclusion, we found elevated temperature may increase the contribution of microbial necromass N to mineral-stabilized soil organic N.

The Survival Benefit and Safety of Splenectomy for Gastric Cancer With Total Gastrectomy: Updated Results.

BACKGROUND: Splenectomy was traditionally performed to dissect the splenic hilar lymph nodes. Considering the important functions of spleen, whether splenectomy would bring beneficial to gastric cancer patients is debatable. This meta-analysis aimed to make an updated evaluation on the effectiveness and safety of splenectomy. METHODS: Literature searches were performed to identify eligible RCTs concerning effectiveness or safety of splenectomy with gastrectomy from PubMed, MEDLINE, CBMdisc, EMBASE, and Cochrane Central Register of Controlled Trials. Two reviewers completed the study selection, data extraction, and quality assessment independently. The meta-analyses were performed by RevMan 5.3. RESULTS: A total of 971 patients from four studies were included (485 in splenectomy group and 486 in spleen preservation group). Splenectomy did not increase 5-year overall survival rate (RR=1.05, 95% CI: 0.96, 1.16) or increase postoperative mortality (RR=1.21, 95% CI: 0.41, 3.54). However, the analysis demonstrated that gastrectomy with splenectomy had significantly higher incidence of postoperative complications (RR=1.80, 95% CI: 1.33, 2.45). No significant differences were found in terms of the number of resected lymph nodes and reoperation rate; however, splenectomy had a tendency to prolong the duration of surgery and hospital stays. Subgroup analyses indicated that splenectomy could not increase overall survival rate for either whole or proximal gastric cancer. Sensitivity analyses also found similar results compared to the primary analyses. CONCLUSIONS: Splenectomy cannot benefit the survival of patients with tumor located at lesser curvature, and it could instead increase postoperative morbidity.

[Effects of nitrogen and phosphorus addition on soil microbial community and amino sugar in a temperate forest on Changbai Mountain, Northeast China].

We carried out an experiment including nitrogen addition (N, 50 kg N·hm-2·a-1), phosphorus addition (P, 25 kg P·hm-2·a-1) and both nitrogen and phosphorus addition (NP, 50 kg N·hm-2·a-1+25 kg P·hm-2·a-1) in a natural Korean pine broad-leaved mixed forest on Changbai Mountain to examine the effects of single and combined N and P additions on soil microbial community composition and amino sugar. The results showed that N and P addition significantly reduced total microbial biomass by 19.5% and 24.6% in the organic layer of soil, while P addition significantly reduced the biomass of bacteria and fungi by 23.8% and 19.3%, respectively. In the mineral layer, N, P and NP addition significantly increased total microbial biomass by 94.8%, 230.9%, and 115.0% respectively, while the biomass of bacteria and fungi were significantly increased under all the treatments. The fungi to bacteria ratio (F/B) was significantly increased in the organic layer by N addition, while was decreased in the mineral layer soil by NP addition. The Gram-positive bacteria to Gram-negative bacteria ratio showed positive response to N, P and NP addition. Soil amino sugars responded differently to different treatments. N, P and NP addition significantly decreased glucosamine content by 41.3%, 48.8% and 36.4% in the organic layer, while N and NP addition increased muramic acid content by 43.0% and 71.1%, respectively. The contents of glucosamine and muramic acid in the mineral layer did not change significantly in response to N addition but increased significantly in response to both P addition and NP addition. The glucosamine to muramic acid ratio in the organic layer significantly decreased under fertilization treatments, indicating that N and P addition increased the relative contribution of bacteria to soil organic carbon accumulation. The changes in soil amino sugar contents were closely related to the change in microbial community composition after N and P addition, both of which were affected by changes in soil chemical properties.

Visceral Fat Area (VFA) Superior to BMI for Predicting Postoperative Complications After Radical Gastrectomy: a Prospective Cohort Study.

BACKGROUND: Obesity may impact surgical outcomes of gastrectomy. Whether visceral fat area (VFA) is a better obesity parameter than body mass index (BMI) is still controversial. The aim of this study is to compare the accuracy and effectiveness of VFA and BMI in predicting the short-term surgical outcomes of gastrectomy. METHODS: Patients who were diagnosed with gastric cancer were measured for BMI and VFA preoperatively and then divided into a VFA-H (VFA-high) group and VFA-L (VFA-low) group, at the cutoff point of 100 cm2, and a BMI-H (BMI-high) group and BMI-L (BMI-low) group, at the cutoff point of 25 kg/m2. The short-term surgical outcomes were compared between the different groups. RESULTS: In total, 276 patients were enrolled in this study; 55 (19.9%) patients were classified into the BMI-H group, and 122 (44.2%) patients were classified into the VFA-H group. There was a significant correlation between BMI and VFA (r = 0.652, p < 0.001). Compared with the VFA-L group, the VFA-H group had a higher incidence of postoperative complications (31.1% vs. 13.0%; p < 0.001), longer operation duration (270.0 (235.0-305.0) vs. 255.0 (223.8-295.0), p = 0.046), and more blood loss (100.0 (100.0-150.0) vs. 80.0 (80.0-100.0), p < 0.001), while the BMI-H group had more blood loss than the BMI-L group (100.0 (100.0-120.0) vs. 100.0(80.0-100.0), p = 0.006). Logistic regression showed that VFA was an independent risk factor for postoperative complications (odds ratio 2.813, 95% CI 1.523-5.194; p = 0.001). CONCLUSION: For gastric cancer patients, VFA is superior to BMI in accurately and effectively illuminating the impact of obesity on short-term surgical outcomes. TRIAL REGISTRATION: Clinicaltrials.gov: NCT02800005.

Is Preoperative Fibrinogen Associated with the Survival Prognosis of Gastric Cancer Patients? A Multi-centered, Propensity Score-Matched Retrospective Study.

BACKGROUND: The prognostic significance of preoperative plasma fibrinogen in patients with operable gastric cancer remains under debate. This study aimed to elucidate the prognostic value of fibrinogen in gastric cancer patients underwent gastrectomy. METHODS: A total of 4351 patients with gastric cancer collected from three comprehensive medical centers were retrospectively evaluated. Patients were categorized by minimum P value using X-tile, while the baseline confounders for fibrinogen was balanced through propensity score matching (PSM). The relationships between fibrinogen and other clinicopathologic features were evaluated, and nomogram was constructed to assess its prognostic improvement compared with TNM staging system. RESULTS: Fibrinogen was significantly correlated with macroscopic type, tumor differentiation, tumor size, and T and N stage. The factors, fibrinogen and T stage as well as N stage, were identified to be independent prognostic factors after PSM. Nomogram based on fibrinogen demonstrated a smaller Akaike information criterion (AIC) and a larger concordance index (C-index) than TNM staging system, illustrating that fibrinogen might be able to improve the prognostic accuracy. CONCLUSIONS: Preoperative plasma fibrinogen levels in gastric cancer patients were significantly correlated with tumor progression, which could be regarded as a reliable marker for survival prognostic prediction.

Robot-Assisted versus Laparoscopic-Assisted Gastrectomy among Gastric Cancer Patients: A Retrospective Short-Term Analysis from a Single Institution in China.

BACKGROUND: The da Vinci robotic system was considered an effectively alternative treatment option for early gastric cancer patients in recent years. The aim of our study was to evaluate the safety and feasibility of robot-assisted gastrectomy in our center. METHODS: This study included 33 patients who underwent robot-assisted gastrectomy (RAG) and 88 patients who underwent laparoscopic-assisted gastrectomy (LAG) between January 2016 and April 2018. Clinicopathological characteristics, surgical parameters, postoperative recovery, and the learning curves of RAG were evaluated. RESULTS: Baseline characteristics between two groups were well balanced. The operation time of RAG was longer than that of LAG (333.1 ± 61.4 min vs. 290.6 ± 39.0 min, p = 0.001), and the estimated blood loss was 62.4 ± 41.2 ml in the RAG group and 77.7 ± 32.3 ml in the LAG group (p = 0.005), respectively. The mean number of examined lymph nodes in RAG was less than that in LAG (30.3 ± 10.2 vs. 37.4 ± 13.7, p = 0.008). However, RAG had an advantage in the dissection of No. 9 lymph nodes (3.4 ± 2.1 vs. 2.5 ± 1.6, p = 0.039). The incidence of postoperative complications was similar in both groups (p = 0.735). There were no significant differences in terms of postoperative recovery between the two groups. The learning curve of RAG showed that the CUSUM value decreased from the 8th case, which suggested a rapid learning curve among experienced surgeons on LAG operations. CONCLUSIONS: RAG was safe and feasible for gastric cancer patients, with superiority in the dissection of No. 9 lymph nodes.

Unveiling the Layer-Dependent Catalytic Activity of PtSe2 Atomic Crystals for the Hydrogen Evolution Reaction.

Two-dimensional (2D) PtSe2 shows the most prominent layer-dependent electrical properties among various 2D materials and high catalytic activity for hydrogen evolution reaction (HER), and therefore, it is an ideal material for exploring the structure-activity correlations in 2D systems. Here, starting with the synthesis of single-crystalline 2D PtSe2 with a controlled number of layers and probing the HER catalytic activity of individual flakes in micro electrochemical cells, we investigated the layer-dependent HER catalytic activity of 2D PtSe2 from both theoretical and experimental perspectives. We clearly demonstrated how the number of layers affects the number of active sites, the electronic structures, and electrical properties of 2D PtSe2 flakes and thus alters their catalytic performance for HER. Our results also highlight the importance of efficient electron transfer in achieving optimum activity for ultrathin electrocatalysts. Our studies greatly enrich our understanding of the structure-activity correlations for 2D catalysts and provide new insight for the design and synthesis of ultrathin catalysts with high activity.

N2O emission from a temperate forest soil during the freeze-thaw period: A mesocosm study.

Nitrous oxide (N2O) is an important greenhouse gas and is involved in the destruction of ozone layer. However, the underlying mechanisms of the high soil N2O emission during the freeze-thaw (FT) period are still unclear. Here, we conducted a mesocosm study with high frequency in situ measurements to explore the responses of soil microbes to the FT cycles and their influences on soil N2O emission. We found the high N2O emission rate during the FT period was mainly due to the release of substrates, the maintenance of high enzyme activities at the freezing stage, and the fast recovery of microbial biomass nitrogen (MBN) and high microbial activities at the thawing stage. Physical isolation of previously produced N2O was an important mechanism for the higher N2O flux at the thawing stage. With increasing numbers of the FT cycles, MBN at the thawing stage remained stable and potential dehydrogenase activities at the thawing stage also remained stable after the first eight FT cycles and only declined during the last two cycles, suggesting the sustainability of the biological mechanisms. Our study suggests that although MBN declined, microbial enzymes could maintain high activities at a few degrees Celsius below zero in this temperate forest soil and produce high N2O fluxes even at the freezing stage, which were trapped under the ice layer and released at the thawing stage, resulting in high soil N2O emission during the FT period.

"Four-Step Procedure" of laparoscopic exploration for gastric cancer in West China Hospital: a retrospective observational analysis from a high-volume institution in China.

BACKGROUND: The preoperative work-up has limitations on finding peritoneal dissemination (PD) in gastric cancer patients. Laparoscopic exploration (LE) can discover radiographically occult PD, obtain accurate stage and avert futile laparotomy. The aim of our study was to introduce "Four-Step Procedure" LE in West China Hospital and further evaluate its safety and feasibility. METHODS: We conducted a retrospective analysis on 165 patients from July 2016 to December 2017 who underwent "Four-Step Procedure" LE in gastrointestinal surgery department of West China Hospital. All the patients were diagnosed with gastric adenocarcinoma without explicit distant metastasis through Computed Tomography and/or Gastrointestinal Ultrasonography. Peritoneal lavage cytological examination (CY) was routinely performed during LE in our research. The "Four-Step" technical process of LE was introduced comprehensively. The clinicopathologic features and the presence of PD or CY at LE were analyzed, and the stratified analysis by cT and cN stages on the proportion of P1 and/or CY1 was also reported in this study. RESULTS: Total of 165 patients accepted LE in our study, among these patients: 27 (16.4%) patients with P1 and/or CY1: 19 (11.5%) patients were found PD (P1), 17 (10.3%) patients with positive cytological examination (CY1) and 9 (3.6%) patients with P1Cy1. The stratified analysis by cT stage indicated that there was no P1 and/or Cy1 in cT1-cT2 stages, 1 (2.7%) patient with P1 and 1 (2.7%) with Cy1 in cT3 stage, 18 (20.0%) patients with P1 and 16 (17.8%) with Cy1 in cT4 stage. After LE, there were 74 (44.8%) patients underwent laparoscopic assistant gastrectomy, 25 (15.2%) patients with open gastrectomy, 50 (30.3%) patients with neoadjuvant chemotherapy and 16 (9.7%) patients with palliative chemotherapy and/or conversion therapy. CONCLUSION: "Four-Step Procedure" LE is reliable and feasible for gastric cancer. From our study, LE has unique superiority on ascertaining PD and cytological examination and LE should be recommended in cT4 stage gastric cancer before resection.