Electrochemical CO_(2)reduction to C_(2)H_(4)can provide a sustainable route to reduce globally accelerating CO_(2)emissions and produce energy-rich chemical feedstocks.However,the poor selectivity in C_(2)H_(4)electr...Electrochemical CO_(2)reduction to C_(2)H_(4)can provide a sustainable route to reduce globally accelerating CO_(2)emissions and produce energy-rich chemical feedstocks.However,the poor selectivity in C_(2)H_(4)electrosynthesis limits its implementation in industrially interesting processes.Herein,we report a composite structured catalyst composed of Ag and Cu_(2)O with different crystal faces to achieve highly efficient reduction of CO_(2)to C_(2)H_(4).The catalyst composed of Ag and octahedral Cu_(2)O enclosed with(111)facet exhibits the best CO_(2)electroreduction performance,with the Faradaic efficiency(FE)and partial current density reaching 66.8%and 17.8 mA cm2 for C_(2)H_(4)product at-1.2 VRHE in 0.5 M KHCO_(3),respectively.Physical characterization and electrochemical test analysis indicate that the high selectivity for C_(2)H_(4)product stems from the synergistic effect of crystal faces control engineering and tandem catalysis.Specifically,Ag can provide optimal availability of CO intermediate by suppressing hydrogen evolution;subsequently,C-C coupling is promoted on the intimate surface of Cu_(2)O with facetdependent selectivity.The insights gained from this work may be beneficial for designing efficient multicomponent catalysts for improving the selectivity of electrochemical CO_(2)reduction reaction to generate C2þproducts.展开更多
AIM: To determine whether the PI3K/AKT/mTOR pathway is activated in proliferative vitreoretinopathy (PVR) in homo-sapiens. METHODS: The retina of controls and patients with PVR were collected and their levels of PI3K,...AIM: To determine whether the PI3K/AKT/mTOR pathway is activated in proliferative vitreoretinopathy (PVR) in homo-sapiens. METHODS: The retina of controls and patients with PVR were collected and their levels of PI3K, phospho-AKT, phospho-mTOR, phospho-p70S6k and phospho-4EBP-1 were determined by Western blot. The cultured human retinal pigment epithelial cell line D407 was treated with a specific mTOR inhibitor, rapamycin (RAPA) or a PI3K inhibitor, LY294002, of various concentrations and durations. Cell morphology was observed by phase contrast microscopy and the proliferation and apoptosis of treated cells were determined by MTT assay and flow cytometry. RESULTS: Levels of PI3K, phospho-AKT, phospho-mTOR, phospho-P70S6K and phospho-4EBP1 was increased in the retina in PVR (P <0.05). In D407 cells, both RAPA and LY294002 significantly inhibited cell proliferation and cell cycle progression, and promoted apoptosis (P <0.05); morphologically, the cells became smaller. Both RAPA and LY294002 reduced levels of phospho-AKT, phospho-mTOR, phospho-p70S6k and phospho-4EBP1 expression (P <0.05). RAPA, but not LY294002, had no significant effect on PI3K expression. CONCLUSION: PI3K/AKT/mTOR signaling pathway is highly activated in the retinal pigment epithelial cells of PVR. The inhibitors of PI3K/AKT/mTOR signaling pathway, RAPA and LY294002, could inhibited the PI3K/AKT/mTOR signaling pathway by reducing the levels of phosphorylation of mTOR pathway components.展开更多
AIM To present clinical characteristics, diagnosis and treatment strategies in elderly patients with biliary diseases.METHODS A total of 289 elderly patients with biliary diseases were enrolled in this study. The clin...AIM To present clinical characteristics, diagnosis and treatment strategies in elderly patients with biliary diseases.METHODS A total of 289 elderly patients with biliary diseases were enrolled in this study. The clinical data relating to these patients were collected in our hospital from June 2013 to May 2016. Patient age, disease type, coexisting diseases, laboratory examinations, surgical methods, postoperative complications and therapeutic outcomes were analyzed. RESULTS The average age of the 289 patients with biliary diseases was 73.9 ± 8.5 years(range, 60-102 years). One hundred and thirty-one patients(45.3%) had one of 10 different biliary diseases, such as gallbladder stones, common bile duct stones, and cholangiocarcinoma. The remaining patients(54.7%) had two types of biliary diseases. One hundred and seventy-nine patients underwent 9 different surgical treatments, including pancreaticoduodenectomy, radical resection of hilar cholangiocarcinoma and laparoscopic cholecystectomy. Ten postoperative complications occurred with an incidence of 39.3%(68/173), and hypopotassemia showed the highest incidence(33.8%, 23/68). One hundred and sixteen patients underwent non-surgical treatments, including anti-infection, symptomatic and supportive treatments. The cure rate was 97.1%(168/173) in the surgical group and 87.1%(101/116) in the non-surgical group. The difference between these two groups was statistically significant(χ2 = 17.227, P < 0.05). CONCLUSION Active treatment of coexisting diseases, management of indications and surgical opportunities, appropriate selection of surgical procedures, improvements in perioperative therapy, and timely management of postoperative complications are key factors in enhancing therapeutic efficacy in elderly patients with biliary diseases.展开更多
The prevalence of diabetic retinopathy (DR) is increasing dramatically as the population of patients with diabetes continues to rise. This paper wants to investigate the prevalence and risk factors of DR in China thro...The prevalence of diabetic retinopathy (DR) is increasing dramatically as the population of patients with diabetes continues to rise. This paper wants to investigate the prevalence and risk factors of DR in China through reviewing the research from Pubmed about population-based epidemic studies. The results of observational studies suggested that the overall prevalence of DR was 1.6%-6.5% in population, 19.9%-43.1% in diabetes and 13.6% in population without diabetes, most of the DR were the mild type, macular edema and vision-threatening were 5.2% and 1.2%. The risk factors for DR were longer duration of diabetes, plasma glucose concentration, concentrations of HbA1c level, higher systolic blood pressure(BP), higher diastolic BP, male gender, rural region, and methods of diabetic treatment and so on. The prevalence of DR which was strongly related to duration of diabetes was higher with the increase of diabetes. DR would be the major leading cause of visual impairment in China, it is very important to prevent DR by early screening and any other methods.展开更多
A multi-material hybrid patternless moulding process for complicated castings has been proposed. Moulding sands used in the hybrid moulding process include silica sand, ceramic sand, chromite sand, zircon sand, and st...A multi-material hybrid patternless moulding process for complicated castings has been proposed. Moulding sands used in the hybrid moulding process include silica sand, ceramic sand, chromite sand, zircon sand, and steel shot sand. Experimental method was used to study the effects of moulding sands on the temperature field, mechanical properties, and dimensional precision of the iron castings. Under the condition that the wall thickness on different sides of the casting is the same, when the wall thickness is greater than 10 mm, the heat storage capacity of the moulding sands from strong to weak is steel shot sand, zircon sand, chromite sand, ceramic foundry sand, and silica sand. Tensile strength of the obtained castings from high to low is zircon sand, chromite sand, steel shot sand, ceramic sand, and silica sand. Contraction rate of the obtained castings from high to low is steel shot sand, zircon sand, chromite sand, silica sand, and ceramic sand. Therefore, steel shot sand and zircon sand can be used as chilled sand, and even can be used instead of cold iron when the casting wall thickness is greater than 10 mm. Zircon sand and chromite sand can be used to obtain high mechanical properties, and silica sand and ceramic sand can be selected to obtain high dimensional precision of the castings. Finally, a typical iron casting piece was tested by experiment using the hybrid moulding process. Excellent performances of iron castings confirm the feasibility of the hybrid moulding process.展开更多
Valsalva retinopathy was described as a particular form of retinopathy, pre-retinal and subinternal limiting membrane haemorrhages in nature that rarely may break through and become subhyloid or intravitreal, secondar...Valsalva retinopathy was described as a particular form of retinopathy, pre-retinal and subinternal limiting membrane haemorrhages in nature that rarely may break through and become subhyloid or intravitreal, secondary to a sudden increase in intrathoracic pressure. We reported a new way that Nd:YAG laser for ILM hyaloidotomy in order to drain the sub-ILM blood into vitreous cavity combined with intravitreal bevacizumab to improve the absorption of blood. Therapeutic alliance make significant outcome, protecting vision in time. We used spectralis OCT to observe sub-ILM mix cells and special ILM structure in this lesion for the first time, as the spectralis OCT can reach histology level imagination.展开更多
Background Catheter ablation for ventricular tachycardia(VT) in patients with arrhythmogenic right ventricular cardiomyopathy(ARVC) has significantly evolved over the past decade. However, different ablation strategie...Background Catheter ablation for ventricular tachycardia(VT) in patients with arrhythmogenic right ventricular cardiomyopathy(ARVC) has significantly evolved over the past decade. However, different ablation strategies showed inconsistency in acute and long-term outcomes. Methods We searched the databases of Medline, Embase and Cochrane Library through October 17, 2019 for studies describing the clinical outcomes of VT ablation in ARVC. Data including VT recurrence, all-cause mortality, acute procedural efficacy and major procedural complications were extracted. A meta-analysis with trial sequential analysis was further performed in comparative studies of endo-epicardial versus endocardial-only ablation. Results A total of 24 studies with 717 participants were enrolled. The literatures of epicardial ablation were mainly published after 2010 with total ICD implantation of 73.7%, acute efficacy of 89.8%, major complication of 5.2%, follow-up of 28.9 months, VT freedom of 75.3%, all-cause mortality of 1.1% and heart transplantation of 0.6%. Meta-analysis of 10 comparative studies revealed that compared with endocardial-only approach, epicardial ablation significantly decreased VT recurrence(OR: 0.50;95% CI: 0.30–0.85;P = 0.010), but somehow increased major procedural complications(OR: 4.64;95% CI: 1.28–16.92;P = 0.02), with not evident improvement of acute efficacy(OR: 2.74;95% CI: 0.98–7.65;P = 0.051) or all-cause mortality(OR: 0.87;95% CI: 0.09–8.31;P = 0.90). Conclusion Catheter ablation for VT in ARVC is feasible and effective. Epicardial ablation is associated with better long-term VT freedom, but with more major complications and unremarkable survival or acute efficacy benefit.展开更多
A 48-year-old woman was admitted with 15-mo history of abdominal pain, diarrhea and hematochezia, and 5-mo history of defecation difficulty. She had been successively admitted to nine hospitals, with an initial diagno...A 48-year-old woman was admitted with 15-mo history of abdominal pain, diarrhea and hematochezia, and 5-mo history of defecation difficulty. She had been successively admitted to nine hospitals, with an initial diagnosis of inflammatory bowel disease with stenotic sigmoid colon. Findings from computed tomography virtual colonoscopy, radiography with meglumine diatrizoate, endoscopic balloon dilatation, metallic stent implantation and later overall colonoscopy, coupled with the newfound knowledge of compound Qingdai pill-taking, led to a subsequent diagnosis of ischemic or toxic bowel disease with sigmoid colon stenosis. The patient was successfully treated by laparoscopic sigmoid colectomy, and postoperative pathological examination revealed ischemic or toxic injury of the sigmoid colon, providing a final diagnosis of druginduced sigmoid colon stenosis. This case highlights that adequate awareness of drug-induced colon stenosis has a decisive role in avoiding misdiagnosis and mistreatment. The diagnostic and therapeutic experiences learnt from this case suggest that endoscopic balloon expansion and colonic metallic stent implantation as bridge treatments were demonstrated as crucial for the differential diagnosis of benign colonic stenosis. Skillful surgical technique and appropriate perioperative management helped to ensure the safety of our patient in subsequent surgery after long-term use of glucocorticoids.展开更多
BACKGROUND The global pandemic of coronavirus disease 2019 pneumonia poses a particular challenge to the emergency surgical treatment of elderly patients with high-risk acute abdominal diseases.Elderly patients are a ...BACKGROUND The global pandemic of coronavirus disease 2019 pneumonia poses a particular challenge to the emergency surgical treatment of elderly patients with high-risk acute abdominal diseases.Elderly patients are a high-risk group for surgical treatment.If the incarceration of gallstones cannot be relieved,emergency surgery is unavoidable.CASE SUMMARY We report an 89-year-old male patient with acute gangrenous cholecystitis and septic shock induced by incarcerated cholecystolithiasis.He had several coexisting,high-risk underlying diseases,had a history of radical gastrectomy for gastric cancer,and was taking aspirin before the operation.Nevertheless,he underwent emergency laparoscopic cholecystectomy,with maintenance of postoperative heart and lung function,successfully recovered,and was discharged on day 8 after the operation.CONCLUSION Emergency surgery for elderly patients with acute abdominal disease is safe and feasible during the coronavirus disease 2019 pandemic,the key is to abide strictly by the hospital's epidemic prevention regulations,fully implement the epidemic prevention procedure for emergency surgery,fully prepare before the operation,accurately perform the operation,and carefully manage the patient postoperatively.展开更多
AIM: To describe the design and preliminary results of the hospital based epidemiological study for diabetic retinopathy (HBESDR), an ongoing epidemiological study to estimate the prevalence of diabetic retinopathy (D...AIM: To describe the design and preliminary results of the hospital based epidemiological study for diabetic retinopathy (HBESDR), an ongoing epidemiological study to estimate the prevalence of diabetic retinopathy (DR) and to elucidate the clinical, anthropometric, biochemical and any other risk factors associated with diabetic retinopathy. METHODS: Totally 2000 diabetes will be recruited from the Diabetes eye clinic in the First Affiliated Hospital of China Medical University. All subjects underwent blood sugar estimation and Oral Glucose Tolerance Test to diagnose diabetes. All diabetes would undergo complete questionnaire, a comprehensive eye examination. Blood and urine would be collected for biochemical investigations. All fundus photographs for any DR will be graded. Participants who need treatment will be sent to the ophthalmic clinic and follow-up interval program for all subjects will be suggested. A computerized database is created for the records. RESULTS: To date, 1174 diabetes have been recruited, there were 350 (29.81%) DR in all diabetes, most of them were with mild non-proliferative diabetic retinopathy (NPDR) (139, 39.71%); 71 (20.29%) moderate NPDR, 66 (18.86%) severe NPDR, 74 (21.14%) proliferative diabetic retinopathy (PDR). Females, longer duration of diabetes, family history of diabetes and hypertension had a statistically significant increase in risk of any DR. CONCLUSION: The study is expected to provide an estimate of the overall prevalence of DR and the prevalence with different duration of diabetes and also a better understanding of the risk factors associated with DR.展开更多
The topological edge states of two-dimensional topological insulators with large energy gaps furnish ideal conduction channels for dissipationless current transport. Transition metal tellurides XTe5X=Zr, Hf) are theor...The topological edge states of two-dimensional topological insulators with large energy gaps furnish ideal conduction channels for dissipationless current transport. Transition metal tellurides XTe5X=Zr, Hf) are theoretically predicted to be large-gap two-dimensional topological insulators, and the experimental observations of their bulk insulating gap and in-gap edge states have been reported, but the topological nature of these edge states still remains to be further elucidated. Here, we report our low-temperature scanning tunneling microscopy/spectroscopy study on single crystals of HfTe5. We demonstrate a full energy gap of ~80 meV near the Fermi level on the surface monolayer of HfTe5 and that such an insulating energy gap gets filled with finite energy states when measured at the monolayer step edges. Remarkably, such states are absent at the edges of a narrow monolayer strip of one-unit-cell in width but persist at both step edges of a unit-cell wide monolayer groove. These experimental observations strongly indicate that the edge states of HfTe5 monolayers are not trivially caused by translational symmetry breaking, instead they are topological in nature protected by the 2 D nontrivial bulk properties.展开更多
BACKGROUND Major adverse cardiac events(MACE) in elderly patients with biliary diseases are the main cause of perioperative accidental death, but no widely recognized quantitative monitoring index of perioperative car...BACKGROUND Major adverse cardiac events(MACE) in elderly patients with biliary diseases are the main cause of perioperative accidental death, but no widely recognized quantitative monitoring index of perioperative cardiac function so far.AIM To investigate the critical values of monitoring indexes for perioperative MACE in elderly patients with biliary diseases.METHODS The clinical data of 208 elderly patients with biliary diseases in our hospital from May 2016 to April 2021 were retrospectively analysed. According to whether MACE occurred during the perioperative period, they were divided into the MACE group and the non-MACE group.RESULTS In the MACE compared with the non-MACE group, postoperative complications, mortality, hospital stay, high sensitivity troponin-Ⅰ(Hs-TnI), creatine kinase isoenzyme(CK-MB), myoglobin(MYO), B-type natriuretic peptide(BNP), and Ddimer(D-D) levels were significantly increased(P < 0.05). Multivariate logistic regression showed that postoperative BNP and D-D were independent risk factors for perioperative MACE, and their cut-off values in the receiver operating characteristic(ROC) curve were 382.65 pg/mL and 0.965 mg/L, respectively.CONCLUSION The postoperative BNP and D-D were independent risk factors for perioperative MACE, with the critical values of 382.65 pg/mL and 0.965 mg/L respectively. Consequently, timely monitoring and effective maintenance of perioperative cardiac function stability are of great clinical significance to further improve the perioperative safety of elderly patients with biliary diseases.展开更多
BACKGROUND Solitary fibrous tumor(SFT) is predominant within the pleura but very rare in the orbit,which is why the diagnosis of orbital SFT poses challenges in clinical practice.Accordingly,an integrated approach tha...BACKGROUND Solitary fibrous tumor(SFT) is predominant within the pleura but very rare in the orbit,which is why the diagnosis of orbital SFT poses challenges in clinical practice.Accordingly,an integrated approach that incorporates specific clinical features,histological,histopathological,and immunohistochemical(IHC) examinations,and molecular analyses is warranted.AIM To retrospectively explore the clinical and imaging characteristics,treatment,outcomes of a series of patients with orbital SFT.METHODS We conducted a retrospective review of a series of patients diagnosed with a histopathologic orbital SFT treated at a single institution.All data on demographics,clinical characteristics,imaging,treatment,postoperative histopathological and IHC examinations,and prognosis were collected.RESULTS In total,13 patients were enrolled,7(53.8%) of whom had the tumor located in the superomedial quadrant of the orbit.Computed tomography revealed a solitary ovoid lesion in 10(76.9%) patients and irregular lesion in 3(23.1%) patients.Magnetic resonance imaging results were as follows:On T1 weighted images,3(23.1%) patients had hypointense mixed signals,whereas 10(76.9%) patients showed isointense mixed signals;on T2 weighted images(T2 WI),3(23.1%),4 (30.8%),and 6(46.2%) patients exhibited hypointense mixed,isointense mixed,and hyperintense signals,respectively.Notably,12(92.3%) patients showed significant enhancement,whereas there were patchy slightly enhanced areas in the tumor.All patients were treated by surgery.IHC analysis demonstrated that the tumor cells were immunoreactive for CD34,CD99,STAT-6,and vimentin in all patients.The lesions showed Ki-67 positivity < 5% in 1(7.7) patient,5%-10% in 10(76.9%),and > 10% in 2(15.4%).Two(15.4%) patients exhibited tumor recurrence.CONCLUSION The clinical manifestations and radiologic characteristics of orbital SFT are diverse and not specific.Accurate diagnosis and treatment require detailed radiological and histopathological/IHC evaluation.展开更多
AIM: To estimate the incidence of cilioretinal arteries among Han population of north China. METHODS: A cross-sectional sample of subjects aged from 20 years old to 80 years old were selected using a cluster sampling ...AIM: To estimate the incidence of cilioretinal arteries among Han population of north China. METHODS: A cross-sectional sample of subjects aged from 20 years old to 80 years old were selected using a cluster sampling technique from Shenyang of Liaoning Province for Diabetic Eye Disease Study. Eligible subjects were recruited in the Community Health Center which took the stereo fundus photography using 45 degrees Non-Mydriatic Fundus Camera. Data were analyzed by SPSS 14.0. RESULTS: The incidence of cilioretinal arteries in 5000 eyes of 2500 subjects was determined. One, two or more cilioretinal arteries were present in 876 of all subjects and in 923 of all the eyes. Difference of presence, number and distribution of cilioretinal arteries was observed. During the subjects, the arteries occurred bilaterally in 6.9% and contributed to some portion of the temporal circulation in 78.3%, nasal circulation 14.8%, respectively. Statistical analysis indicated that there was no significant difference in incidence between men and women, left and right eyes (P>0.05). CONCLUSION: 35.0% persons have the cilioretinal arteries in Han population of north China. Men and women have an equal distribution of cilioretinal arteries.展开更多
BACKGROUND Missed or delayed diagnosis of cervical spine instability after acute trauma can have catastrophic consequences for the patient,resulting in severe neurological impairment.Currently,however,there is no cons...BACKGROUND Missed or delayed diagnosis of cervical spine instability after acute trauma can have catastrophic consequences for the patient,resulting in severe neurological impairment.Currently,however,there is no consensus on the optimal strategy for diagnosing occult cervical spine instability.Thus,we present a case of occult cervical spine instability and provide a clinical algorithm to aid physicians in diagnosing occult instability of the cervical spine.CASE SUMMARY A 57-year-old man presented with cervical spine pain and inability to stand following a serious fall from a height of 2 m.No obvious vertebral fracture or dislocation was found at the time on standard lateral X-ray,computed tomography,and magnetic resonance imaging(MRI).Subsequently,the initial surgical plan was unilateral open-door laminoplasty(C3-7)with alternative levels of centerpiece mini-plate fixation(C3,5,and 7).However,the intraoperative C-arm fluoroscopic X-rays revealed significantly increased intervertebral space at C5-6,indicating instability at this level that was previously unrecognized on preoperative imaging.We finally performed lateral mass fixation and fusion at the C5-6 level.Looking back at the preoperative images,we found that the preoperative T2 MRI showed non-obvious high signal intensity at the C5-6 intervertebral disc and posterior interspinous ligament.CONCLUSION MRI of cervical spine trauma patients should be carefully reviewed to detect disco-ligamentous injury,which will lead to further cervical spine instability.In patients with highly suspected cervical spine instability indicated on MRI,lateral X-ray under traction or after anesthesia and muscle relaxation needs to be performed to avoid missed diagnoses of occult cervical instability.展开更多
Value at Risk (VaR) is an important tool for estimating the risk of a financial portfolio under significant loss. Although Monte Carlo simulation is a powerful tool for estimating VaR, it is quite inefficient since th...Value at Risk (VaR) is an important tool for estimating the risk of a financial portfolio under significant loss. Although Monte Carlo simulation is a powerful tool for estimating VaR, it is quite inefficient since the event of significant loss is usually rare. Previous studies suggest that the performance of the Monte Carlo simulation can be improved by impor-tance sampling if the market returns follow the normality or the distributions. The first contribution of our paper is to extend the importance sampling method for dealing with jump-diffusion market returns, which can more precisely model the phenomenon of high peaks, heavy tails, and jumps of market returns mentioned in numerous empirical study papers. This paper also points out that for portfolios of which the huge loss is triggered by significantly distinct events, naively applying importance sampling method can result in poor performance. The second contribution of our paper is to develop the hybrid importance sampling method for the aforementioned problem. Our method decomposes a Monte Carlo simulation into sub simulations, and each sub simulation focuses only on one huge loss event. Thus the perform-ance for each sub simulation is improved by importance sampling method, and overall performance is optimized by determining the allotment of samples to each sub simulation by Lagrange’s multiplier. Numerical experiments are given to verify the superiority of our method.展开更多
Dear Editor,Cancer neuroscience is an emerging topic in cancer research(Monje et al.,2020;Shi et al.,2022).Perineural invasion(PNI),defined as the neoplastic invasion of tumor cells into or surrounding the different l...Dear Editor,Cancer neuroscience is an emerging topic in cancer research(Monje et al.,2020;Shi et al.,2022).Perineural invasion(PNI),defined as the neoplastic invasion of tumor cells into or surrounding the different layers of nervous fibers(epineural,perineural,and endoneural spaces of the neuronal sheath),is associated with aggressive tumor behavior.展开更多
To the Editor: According to the Chinese National Bureau of Statistics in October 1999, the population aged ≥60 years reached 10% of the total population, indicating that China was entering into an aging society, By ...To the Editor: According to the Chinese National Bureau of Statistics in October 1999, the population aged ≥60 years reached 10% of the total population, indicating that China was entering into an aging society, By the end of 2017, the population aged ≥60 years was 240,900,000, accounting for 17.3% of the total population. With the rapidly aging population, binary diseases in elderly patients have become frequent in China, with a morbidity rate of 8-11%. Due to lowered stress response, defense ability, and immunity, biliary diseases in elderly patients are characterized by an increase in coexisting diseases, rapid progression, poor surgical tolerance, high surgical risk, frequent postoperative complications, and high mortality. Thus, it is important to explore effective treatment methods in elderly patients with biliary diseases. Based on our clinical experience in the treatment of elderly patients with biliary diseases,[1] along with previous studies, this report presented the current status of surgical treatment of elderly patients with biliary diseases in China.[2]展开更多
Two-dimensional(2D) materials with potential applications in photonic and optoelectronic devices have attracted increasing attention due to their unique structures and captivating properties. However, generation of st...Two-dimensional(2D) materials with potential applications in photonic and optoelectronic devices have attracted increasing attention due to their unique structures and captivating properties. However, generation of stable high-energy ultrashort pulses requires further boosting of these materials' optical properties, such as higher damage threshold and larger modulation depth. Here we investigate a new type of heterostructure material with uniformity by employing the magnetron sputtering technique. Heterostructure materials are synthesized with van der Waals heterostructures consisting of MoS_2 and Sb_2Te_3. The bandgap, carrier mobility, and carrier concentration of the MoS_2-Sb_2Te_3-MoS_2 heterostructure materials are calculated theoretically. By using these materials as saturable absorbers(SAs), applications in fiber lasers with Q-switching and mode-locking states are demonstrated experimentally. The modulation depth and damage threshold of SAs are measured to be 64.17%and 14.13 J∕cm^2, respectively. Both theoretical and experimental results indicate that MoS_2-Sb_2Te_3-MoS_2 heterostructure materials have large modulation depth, and can resist high power during the generation of ultrashort pulses. The MoS_2-Sb_2Te_3-MoS_2 heterostructure materials have the advantages of low cost, high reliability, and suitability for mass production, and provide a promising solution for the development of 2D-material-based devices with desirable electronic and optoelectronic properties.展开更多
基金This work was supported by the University of Science and Technology Beijing.DG acknowledges the financial support from 111 Project(no.B170003)Foshan Science and Technology Innovation Project(no.2018IT100363).
文摘Electrochemical CO_(2)reduction to C_(2)H_(4)can provide a sustainable route to reduce globally accelerating CO_(2)emissions and produce energy-rich chemical feedstocks.However,the poor selectivity in C_(2)H_(4)electrosynthesis limits its implementation in industrially interesting processes.Herein,we report a composite structured catalyst composed of Ag and Cu_(2)O with different crystal faces to achieve highly efficient reduction of CO_(2)to C_(2)H_(4).The catalyst composed of Ag and octahedral Cu_(2)O enclosed with(111)facet exhibits the best CO_(2)electroreduction performance,with the Faradaic efficiency(FE)and partial current density reaching 66.8%and 17.8 mA cm2 for C_(2)H_(4)product at-1.2 VRHE in 0.5 M KHCO_(3),respectively.Physical characterization and electrochemical test analysis indicate that the high selectivity for C_(2)H_(4)product stems from the synergistic effect of crystal faces control engineering and tandem catalysis.Specifically,Ag can provide optimal availability of CO intermediate by suppressing hydrogen evolution;subsequently,C-C coupling is promoted on the intimate surface of Cu_(2)O with facetdependent selectivity.The insights gained from this work may be beneficial for designing efficient multicomponent catalysts for improving the selectivity of electrochemical CO_(2)reduction reaction to generate C2þproducts.
基金Scientific Research Project of Education Department of Liaoning Province, China (No.L2010676)Project of Science and Technology Commission of Shenyang City,China(No.F10-149-9-58)Doctoral Foundation of Ministry of Education of China (No.20102104120027)
文摘AIM: To determine whether the PI3K/AKT/mTOR pathway is activated in proliferative vitreoretinopathy (PVR) in homo-sapiens. METHODS: The retina of controls and patients with PVR were collected and their levels of PI3K, phospho-AKT, phospho-mTOR, phospho-p70S6k and phospho-4EBP-1 were determined by Western blot. The cultured human retinal pigment epithelial cell line D407 was treated with a specific mTOR inhibitor, rapamycin (RAPA) or a PI3K inhibitor, LY294002, of various concentrations and durations. Cell morphology was observed by phase contrast microscopy and the proliferation and apoptosis of treated cells were determined by MTT assay and flow cytometry. RESULTS: Levels of PI3K, phospho-AKT, phospho-mTOR, phospho-P70S6K and phospho-4EBP1 was increased in the retina in PVR (P <0.05). In D407 cells, both RAPA and LY294002 significantly inhibited cell proliferation and cell cycle progression, and promoted apoptosis (P <0.05); morphologically, the cells became smaller. Both RAPA and LY294002 reduced levels of phospho-AKT, phospho-mTOR, phospho-p70S6k and phospho-4EBP1 expression (P <0.05). RAPA, but not LY294002, had no significant effect on PI3K expression. CONCLUSION: PI3K/AKT/mTOR signaling pathway is highly activated in the retinal pigment epithelial cells of PVR. The inhibitors of PI3K/AKT/mTOR signaling pathway, RAPA and LY294002, could inhibited the PI3K/AKT/mTOR signaling pathway by reducing the levels of phosphorylation of mTOR pathway components.
基金Supported by the Science and Technology Project of State Grid Corporation of China,No.SGHB0000AJJS1400182
文摘AIM To present clinical characteristics, diagnosis and treatment strategies in elderly patients with biliary diseases.METHODS A total of 289 elderly patients with biliary diseases were enrolled in this study. The clinical data relating to these patients were collected in our hospital from June 2013 to May 2016. Patient age, disease type, coexisting diseases, laboratory examinations, surgical methods, postoperative complications and therapeutic outcomes were analyzed. RESULTS The average age of the 289 patients with biliary diseases was 73.9 ± 8.5 years(range, 60-102 years). One hundred and thirty-one patients(45.3%) had one of 10 different biliary diseases, such as gallbladder stones, common bile duct stones, and cholangiocarcinoma. The remaining patients(54.7%) had two types of biliary diseases. One hundred and seventy-nine patients underwent 9 different surgical treatments, including pancreaticoduodenectomy, radical resection of hilar cholangiocarcinoma and laparoscopic cholecystectomy. Ten postoperative complications occurred with an incidence of 39.3%(68/173), and hypopotassemia showed the highest incidence(33.8%, 23/68). One hundred and sixteen patients underwent non-surgical treatments, including anti-infection, symptomatic and supportive treatments. The cure rate was 97.1%(168/173) in the surgical group and 87.1%(101/116) in the non-surgical group. The difference between these two groups was statistically significant(χ2 = 17.227, P < 0.05). CONCLUSION Active treatment of coexisting diseases, management of indications and surgical opportunities, appropriate selection of surgical procedures, improvements in perioperative therapy, and timely management of postoperative complications are key factors in enhancing therapeutic efficacy in elderly patients with biliary diseases.
文摘The prevalence of diabetic retinopathy (DR) is increasing dramatically as the population of patients with diabetes continues to rise. This paper wants to investigate the prevalence and risk factors of DR in China through reviewing the research from Pubmed about population-based epidemic studies. The results of observational studies suggested that the overall prevalence of DR was 1.6%-6.5% in population, 19.9%-43.1% in diabetes and 13.6% in population without diabetes, most of the DR were the mild type, macular edema and vision-threatening were 5.2% and 1.2%. The risk factors for DR were longer duration of diabetes, plasma glucose concentration, concentrations of HbA1c level, higher systolic blood pressure(BP), higher diastolic BP, male gender, rural region, and methods of diabetic treatment and so on. The prevalence of DR which was strongly related to duration of diabetes was higher with the increase of diabetes. DR would be the major leading cause of visual impairment in China, it is very important to prevent DR by early screening and any other methods.
基金financially supported by the National Science Foundation for Distinguished Young Scholars of China(Grant No.51525503)the National Program for Support of Top-notch Young Professionals(Grant No.W02070184)
文摘A multi-material hybrid patternless moulding process for complicated castings has been proposed. Moulding sands used in the hybrid moulding process include silica sand, ceramic sand, chromite sand, zircon sand, and steel shot sand. Experimental method was used to study the effects of moulding sands on the temperature field, mechanical properties, and dimensional precision of the iron castings. Under the condition that the wall thickness on different sides of the casting is the same, when the wall thickness is greater than 10 mm, the heat storage capacity of the moulding sands from strong to weak is steel shot sand, zircon sand, chromite sand, ceramic foundry sand, and silica sand. Tensile strength of the obtained castings from high to low is zircon sand, chromite sand, steel shot sand, ceramic sand, and silica sand. Contraction rate of the obtained castings from high to low is steel shot sand, zircon sand, chromite sand, silica sand, and ceramic sand. Therefore, steel shot sand and zircon sand can be used as chilled sand, and even can be used instead of cold iron when the casting wall thickness is greater than 10 mm. Zircon sand and chromite sand can be used to obtain high mechanical properties, and silica sand and ceramic sand can be selected to obtain high dimensional precision of the castings. Finally, a typical iron casting piece was tested by experiment using the hybrid moulding process. Excellent performances of iron castings confirm the feasibility of the hybrid moulding process.
文摘Valsalva retinopathy was described as a particular form of retinopathy, pre-retinal and subinternal limiting membrane haemorrhages in nature that rarely may break through and become subhyloid or intravitreal, secondary to a sudden increase in intrathoracic pressure. We reported a new way that Nd:YAG laser for ILM hyaloidotomy in order to drain the sub-ILM blood into vitreous cavity combined with intravitreal bevacizumab to improve the absorption of blood. Therapeutic alliance make significant outcome, protecting vision in time. We used spectralis OCT to observe sub-ILM mix cells and special ILM structure in this lesion for the first time, as the spectralis OCT can reach histology level imagination.
基金supported by the National Natural Science Foundation (81570309)National Key R&D Program of China (2017YFC1307800)。
文摘Background Catheter ablation for ventricular tachycardia(VT) in patients with arrhythmogenic right ventricular cardiomyopathy(ARVC) has significantly evolved over the past decade. However, different ablation strategies showed inconsistency in acute and long-term outcomes. Methods We searched the databases of Medline, Embase and Cochrane Library through October 17, 2019 for studies describing the clinical outcomes of VT ablation in ARVC. Data including VT recurrence, all-cause mortality, acute procedural efficacy and major procedural complications were extracted. A meta-analysis with trial sequential analysis was further performed in comparative studies of endo-epicardial versus endocardial-only ablation. Results A total of 24 studies with 717 participants were enrolled. The literatures of epicardial ablation were mainly published after 2010 with total ICD implantation of 73.7%, acute efficacy of 89.8%, major complication of 5.2%, follow-up of 28.9 months, VT freedom of 75.3%, all-cause mortality of 1.1% and heart transplantation of 0.6%. Meta-analysis of 10 comparative studies revealed that compared with endocardial-only approach, epicardial ablation significantly decreased VT recurrence(OR: 0.50;95% CI: 0.30–0.85;P = 0.010), but somehow increased major procedural complications(OR: 4.64;95% CI: 1.28–16.92;P = 0.02), with not evident improvement of acute efficacy(OR: 2.74;95% CI: 0.98–7.65;P = 0.051) or all-cause mortality(OR: 0.87;95% CI: 0.09–8.31;P = 0.90). Conclusion Catheter ablation for VT in ARVC is feasible and effective. Epicardial ablation is associated with better long-term VT freedom, but with more major complications and unremarkable survival or acute efficacy benefit.
基金Supported by the Science and Technology Project of State Grid Corporation of China,No.SGHB0000AJJS1400182
文摘A 48-year-old woman was admitted with 15-mo history of abdominal pain, diarrhea and hematochezia, and 5-mo history of defecation difficulty. She had been successively admitted to nine hospitals, with an initial diagnosis of inflammatory bowel disease with stenotic sigmoid colon. Findings from computed tomography virtual colonoscopy, radiography with meglumine diatrizoate, endoscopic balloon dilatation, metallic stent implantation and later overall colonoscopy, coupled with the newfound knowledge of compound Qingdai pill-taking, led to a subsequent diagnosis of ischemic or toxic bowel disease with sigmoid colon stenosis. The patient was successfully treated by laparoscopic sigmoid colectomy, and postoperative pathological examination revealed ischemic or toxic injury of the sigmoid colon, providing a final diagnosis of druginduced sigmoid colon stenosis. This case highlights that adequate awareness of drug-induced colon stenosis has a decisive role in avoiding misdiagnosis and mistreatment. The diagnostic and therapeutic experiences learnt from this case suggest that endoscopic balloon expansion and colonic metallic stent implantation as bridge treatments were demonstrated as crucial for the differential diagnosis of benign colonic stenosis. Skillful surgical technique and appropriate perioperative management helped to ensure the safety of our patient in subsequent surgery after long-term use of glucocorticoids.
基金Beijing Municipal Science and Technology Commission,No.Z171100000417056。
文摘BACKGROUND The global pandemic of coronavirus disease 2019 pneumonia poses a particular challenge to the emergency surgical treatment of elderly patients with high-risk acute abdominal diseases.Elderly patients are a high-risk group for surgical treatment.If the incarceration of gallstones cannot be relieved,emergency surgery is unavoidable.CASE SUMMARY We report an 89-year-old male patient with acute gangrenous cholecystitis and septic shock induced by incarcerated cholecystolithiasis.He had several coexisting,high-risk underlying diseases,had a history of radical gastrectomy for gastric cancer,and was taking aspirin before the operation.Nevertheless,he underwent emergency laparoscopic cholecystectomy,with maintenance of postoperative heart and lung function,successfully recovered,and was discharged on day 8 after the operation.CONCLUSION Emergency surgery for elderly patients with acute abdominal disease is safe and feasible during the coronavirus disease 2019 pandemic,the key is to abide strictly by the hospital's epidemic prevention regulations,fully implement the epidemic prevention procedure for emergency surgery,fully prepare before the operation,accurately perform the operation,and carefully manage the patient postoperatively.
基金Supported by Liaoning Medical Peak Construction Projects Foundation,China(No.2010016)
文摘AIM: To describe the design and preliminary results of the hospital based epidemiological study for diabetic retinopathy (HBESDR), an ongoing epidemiological study to estimate the prevalence of diabetic retinopathy (DR) and to elucidate the clinical, anthropometric, biochemical and any other risk factors associated with diabetic retinopathy. METHODS: Totally 2000 diabetes will be recruited from the Diabetes eye clinic in the First Affiliated Hospital of China Medical University. All subjects underwent blood sugar estimation and Oral Glucose Tolerance Test to diagnose diabetes. All diabetes would undergo complete questionnaire, a comprehensive eye examination. Blood and urine would be collected for biochemical investigations. All fundus photographs for any DR will be graded. Participants who need treatment will be sent to the ophthalmic clinic and follow-up interval program for all subjects will be suggested. A computerized database is created for the records. RESULTS: To date, 1174 diabetes have been recruited, there were 350 (29.81%) DR in all diabetes, most of them were with mild non-proliferative diabetic retinopathy (NPDR) (139, 39.71%); 71 (20.29%) moderate NPDR, 66 (18.86%) severe NPDR, 74 (21.14%) proliferative diabetic retinopathy (PDR). Females, longer duration of diabetes, family history of diabetes and hypertension had a statistically significant increase in risk of any DR. CONCLUSION: The study is expected to provide an estimate of the overall prevalence of DR and the prevalence with different duration of diabetes and also a better understanding of the risk factors associated with DR.
基金Supported by the Chinese Academy of Sciencesthe National Natural Science Foundation of China under Grant No 11227903+4 种基金the BM-STC under Grant No Z181100004218007the National Basic Research Program of China under Grant Nos 2015CB921300and 2015CB921304National Key R&D Program of China under Grant No 2017YFA0302903the Strategic Priority Research Program B of the Chinese Academy of Sciences under Grant Nos XDB04040300 and XDB07000000Beijing Municipal Science&Technology Commission(Z181100004218007)
文摘The topological edge states of two-dimensional topological insulators with large energy gaps furnish ideal conduction channels for dissipationless current transport. Transition metal tellurides XTe5X=Zr, Hf) are theoretically predicted to be large-gap two-dimensional topological insulators, and the experimental observations of their bulk insulating gap and in-gap edge states have been reported, but the topological nature of these edge states still remains to be further elucidated. Here, we report our low-temperature scanning tunneling microscopy/spectroscopy study on single crystals of HfTe5. We demonstrate a full energy gap of ~80 meV near the Fermi level on the surface monolayer of HfTe5 and that such an insulating energy gap gets filled with finite energy states when measured at the monolayer step edges. Remarkably, such states are absent at the edges of a narrow monolayer strip of one-unit-cell in width but persist at both step edges of a unit-cell wide monolayer groove. These experimental observations strongly indicate that the edge states of HfTe5 monolayers are not trivially caused by translational symmetry breaking, instead they are topological in nature protected by the 2 D nontrivial bulk properties.
基金Supported by Beijing Municipal Science&Technology Commission,No.Z171100000417056.
文摘BACKGROUND Major adverse cardiac events(MACE) in elderly patients with biliary diseases are the main cause of perioperative accidental death, but no widely recognized quantitative monitoring index of perioperative cardiac function so far.AIM To investigate the critical values of monitoring indexes for perioperative MACE in elderly patients with biliary diseases.METHODS The clinical data of 208 elderly patients with biliary diseases in our hospital from May 2016 to April 2021 were retrospectively analysed. According to whether MACE occurred during the perioperative period, they were divided into the MACE group and the non-MACE group.RESULTS In the MACE compared with the non-MACE group, postoperative complications, mortality, hospital stay, high sensitivity troponin-Ⅰ(Hs-TnI), creatine kinase isoenzyme(CK-MB), myoglobin(MYO), B-type natriuretic peptide(BNP), and Ddimer(D-D) levels were significantly increased(P < 0.05). Multivariate logistic regression showed that postoperative BNP and D-D were independent risk factors for perioperative MACE, and their cut-off values in the receiver operating characteristic(ROC) curve were 382.65 pg/mL and 0.965 mg/L, respectively.CONCLUSION The postoperative BNP and D-D were independent risk factors for perioperative MACE, with the critical values of 382.65 pg/mL and 0.965 mg/L respectively. Consequently, timely monitoring and effective maintenance of perioperative cardiac function stability are of great clinical significance to further improve the perioperative safety of elderly patients with biliary diseases.
文摘BACKGROUND Solitary fibrous tumor(SFT) is predominant within the pleura but very rare in the orbit,which is why the diagnosis of orbital SFT poses challenges in clinical practice.Accordingly,an integrated approach that incorporates specific clinical features,histological,histopathological,and immunohistochemical(IHC) examinations,and molecular analyses is warranted.AIM To retrospectively explore the clinical and imaging characteristics,treatment,outcomes of a series of patients with orbital SFT.METHODS We conducted a retrospective review of a series of patients diagnosed with a histopathologic orbital SFT treated at a single institution.All data on demographics,clinical characteristics,imaging,treatment,postoperative histopathological and IHC examinations,and prognosis were collected.RESULTS In total,13 patients were enrolled,7(53.8%) of whom had the tumor located in the superomedial quadrant of the orbit.Computed tomography revealed a solitary ovoid lesion in 10(76.9%) patients and irregular lesion in 3(23.1%) patients.Magnetic resonance imaging results were as follows:On T1 weighted images,3(23.1%) patients had hypointense mixed signals,whereas 10(76.9%) patients showed isointense mixed signals;on T2 weighted images(T2 WI),3(23.1%),4 (30.8%),and 6(46.2%) patients exhibited hypointense mixed,isointense mixed,and hyperintense signals,respectively.Notably,12(92.3%) patients showed significant enhancement,whereas there were patchy slightly enhanced areas in the tumor.All patients were treated by surgery.IHC analysis demonstrated that the tumor cells were immunoreactive for CD34,CD99,STAT-6,and vimentin in all patients.The lesions showed Ki-67 positivity < 5% in 1(7.7) patient,5%-10% in 10(76.9%),and > 10% in 2(15.4%).Two(15.4%) patients exhibited tumor recurrence.CONCLUSION The clinical manifestations and radiologic characteristics of orbital SFT are diverse and not specific.Accurate diagnosis and treatment require detailed radiological and histopathological/IHC evaluation.
基金Supported by Liaoning S & T Project,China (No.2009225005)
文摘AIM: To estimate the incidence of cilioretinal arteries among Han population of north China. METHODS: A cross-sectional sample of subjects aged from 20 years old to 80 years old were selected using a cluster sampling technique from Shenyang of Liaoning Province for Diabetic Eye Disease Study. Eligible subjects were recruited in the Community Health Center which took the stereo fundus photography using 45 degrees Non-Mydriatic Fundus Camera. Data were analyzed by SPSS 14.0. RESULTS: The incidence of cilioretinal arteries in 5000 eyes of 2500 subjects was determined. One, two or more cilioretinal arteries were present in 876 of all subjects and in 923 of all the eyes. Difference of presence, number and distribution of cilioretinal arteries was observed. During the subjects, the arteries occurred bilaterally in 6.9% and contributed to some portion of the temporal circulation in 78.3%, nasal circulation 14.8%, respectively. Statistical analysis indicated that there was no significant difference in incidence between men and women, left and right eyes (P>0.05). CONCLUSION: 35.0% persons have the cilioretinal arteries in Han population of north China. Men and women have an equal distribution of cilioretinal arteries.
基金Supported by grants from China Postdoctoral Science Foundation General Program No.2019M653417Sichuan Science and Technology Program,No.2020YJ0025,No.2017SZ0046,and No.2017SZDZX0021+1 种基金Post-Doctor Research Project,Sichuan University,No.2019SCU12043and International Postdoctoral Exchange Fellowship Program,No.PC2019060.
文摘BACKGROUND Missed or delayed diagnosis of cervical spine instability after acute trauma can have catastrophic consequences for the patient,resulting in severe neurological impairment.Currently,however,there is no consensus on the optimal strategy for diagnosing occult cervical spine instability.Thus,we present a case of occult cervical spine instability and provide a clinical algorithm to aid physicians in diagnosing occult instability of the cervical spine.CASE SUMMARY A 57-year-old man presented with cervical spine pain and inability to stand following a serious fall from a height of 2 m.No obvious vertebral fracture or dislocation was found at the time on standard lateral X-ray,computed tomography,and magnetic resonance imaging(MRI).Subsequently,the initial surgical plan was unilateral open-door laminoplasty(C3-7)with alternative levels of centerpiece mini-plate fixation(C3,5,and 7).However,the intraoperative C-arm fluoroscopic X-rays revealed significantly increased intervertebral space at C5-6,indicating instability at this level that was previously unrecognized on preoperative imaging.We finally performed lateral mass fixation and fusion at the C5-6 level.Looking back at the preoperative images,we found that the preoperative T2 MRI showed non-obvious high signal intensity at the C5-6 intervertebral disc and posterior interspinous ligament.CONCLUSION MRI of cervical spine trauma patients should be carefully reviewed to detect disco-ligamentous injury,which will lead to further cervical spine instability.In patients with highly suspected cervical spine instability indicated on MRI,lateral X-ray under traction or after anesthesia and muscle relaxation needs to be performed to avoid missed diagnoses of occult cervical instability.
文摘Value at Risk (VaR) is an important tool for estimating the risk of a financial portfolio under significant loss. Although Monte Carlo simulation is a powerful tool for estimating VaR, it is quite inefficient since the event of significant loss is usually rare. Previous studies suggest that the performance of the Monte Carlo simulation can be improved by impor-tance sampling if the market returns follow the normality or the distributions. The first contribution of our paper is to extend the importance sampling method for dealing with jump-diffusion market returns, which can more precisely model the phenomenon of high peaks, heavy tails, and jumps of market returns mentioned in numerous empirical study papers. This paper also points out that for portfolios of which the huge loss is triggered by significantly distinct events, naively applying importance sampling method can result in poor performance. The second contribution of our paper is to develop the hybrid importance sampling method for the aforementioned problem. Our method decomposes a Monte Carlo simulation into sub simulations, and each sub simulation focuses only on one huge loss event. Thus the perform-ance for each sub simulation is improved by importance sampling method, and overall performance is optimized by determining the allotment of samples to each sub simulation by Lagrange’s multiplier. Numerical experiments are given to verify the superiority of our method.
基金supported by the National Natural Science Foundation of China(82173153,81902370,82103076,81902377,92168111)Shanghai Municipal Education Commission-Gaofeng Clinical Medicine Grant Support(20181708)+4 种基金the Program of Shanghai Academic/Technology Research Leader(19XD1403400)Shanghai Sailing Program(19YF1445700)Shanghai Chenguang Program(19CG17)the Medicine and Engineering Interdisciplinary Research Fund of Shanghai Jiao Tong University(YG2021ZD08)the Innovative Research Team of High-Level Local Universities in Shanghai(SHSMU-ZDCX20210802)。
文摘Dear Editor,Cancer neuroscience is an emerging topic in cancer research(Monje et al.,2020;Shi et al.,2022).Perineural invasion(PNI),defined as the neoplastic invasion of tumor cells into or surrounding the different layers of nervous fibers(epineural,perineural,and endoneural spaces of the neuronal sheath),is associated with aggressive tumor behavior.
文摘To the Editor: According to the Chinese National Bureau of Statistics in October 1999, the population aged ≥60 years reached 10% of the total population, indicating that China was entering into an aging society, By the end of 2017, the population aged ≥60 years was 240,900,000, accounting for 17.3% of the total population. With the rapidly aging population, binary diseases in elderly patients have become frequent in China, with a morbidity rate of 8-11%. Due to lowered stress response, defense ability, and immunity, biliary diseases in elderly patients are characterized by an increase in coexisting diseases, rapid progression, poor surgical tolerance, high surgical risk, frequent postoperative complications, and high mortality. Thus, it is important to explore effective treatment methods in elderly patients with biliary diseases. Based on our clinical experience in the treatment of elderly patients with biliary diseases,[1] along with previous studies, this report presented the current status of surgical treatment of elderly patients with biliary diseases in China.[2]
基金National Natural Science Foundation of China(NSFC)(11674036)Beijing University of Posts and Telecommunications(BUPT)(IPOC2016ZT04,IPOC2017ZZ05)+2 种基金Beijing Youth Top-Notch Talent Support Program(2017000026833ZK08)Special Program for Applied Research on Super Computation of the NSFC Guangdong Joint Fund(U1501501)XAFS Station(BL14W1)
文摘Two-dimensional(2D) materials with potential applications in photonic and optoelectronic devices have attracted increasing attention due to their unique structures and captivating properties. However, generation of stable high-energy ultrashort pulses requires further boosting of these materials' optical properties, such as higher damage threshold and larger modulation depth. Here we investigate a new type of heterostructure material with uniformity by employing the magnetron sputtering technique. Heterostructure materials are synthesized with van der Waals heterostructures consisting of MoS_2 and Sb_2Te_3. The bandgap, carrier mobility, and carrier concentration of the MoS_2-Sb_2Te_3-MoS_2 heterostructure materials are calculated theoretically. By using these materials as saturable absorbers(SAs), applications in fiber lasers with Q-switching and mode-locking states are demonstrated experimentally. The modulation depth and damage threshold of SAs are measured to be 64.17%and 14.13 J∕cm^2, respectively. Both theoretical and experimental results indicate that MoS_2-Sb_2Te_3-MoS_2 heterostructure materials have large modulation depth, and can resist high power during the generation of ultrashort pulses. The MoS_2-Sb_2Te_3-MoS_2 heterostructure materials have the advantages of low cost, high reliability, and suitability for mass production, and provide a promising solution for the development of 2D-material-based devices with desirable electronic and optoelectronic properties.