Edge effect during microwave plasma chemical vapor deposition diamond-film:Multiphysics simulation and experimental verification

This study focused on the investigation of the edge effect of diamond films deposited by microwave plasma chemical vapor de-position.Substrate bulge height△h is a factor that affects the edge effect,and it was used to simulate plasma and guide the diamond-film deposition experiments.Finite-element software COMSOL Multiphysics was used to construct a multiphysics(electromagnetic,plasma,and fluid heat transfer fields)coupling model based on electron collision reaction.Raman spectroscopy and scanning electron microscopy were performed to characterize the experimental growth and validate the model.The simulation results reflected the experimental trends observed.Plasma discharge at the edge of the substrate accelerated due to the increase in△h(△h=0-3 mm),and the values of electron density(n_(c)),molar concentration of H(C_(H)),and molar concentration of CH_(3)(C_(CH_(3)))doubled at the edge(for the special concave sample with△h=−1 mm,the active chemical groups exhibited a decreased molar concentration at the edge of the substrate).At=0-3 mm,a high diamond growth rate and a large diamond grain size were observed at the edge of the substrate,and their values increased with.The uniformity of film thickness decreased with.The Raman spectra of all samples revealed the first-order characteristic peak of dia-mond near 1332 cm^(−1).When△h=−1 mm,tensile stress occurred in all regions of the film.When△h=1-3 mm,all areas in the film ex-hibited compressive stress.

Tuning mechanical behaviors of highly entangled hydrogels with the random distribution of mobile entanglements

Highly entangled hydrogels exhibit excellent mechanical properties,including high toughness,high stretchability,and low hysteresis.By considering the evolution of randomly distributed entanglements within the polymer network upon mechanical stretches,we develop a constitutive theory to describe the large stretch behaviors of these hydrogels.In the theory,we utilize a representative volume element(RVE)in the shape of a cube,within which there exists an averaged chain segment along each edge and a mobile entanglement at each corner.By employing an explicit method,we decouple the elasticity of the hydrogels from the sliding motion of their entanglements,and derive the stress-stretch relations for these hydrogels.The present theoretical analysis is in agreement with experiment,and highlights the significant influence of the entanglement distribution within the hydrogels on their elasticity.We also implement the present developed constitutive theory into a commercial finite element software,and the subsequent simulations demonstrate that the exact distribution of entanglements strongly affects the mechanical behaviors of the structures of these hydrogels.Overall,the present theory provides valuable insights into the deformation mechanism of highly entangled hydrogels,and can aid in the design of these hydrogels with enhanced performance.

Reconstruction and recovery of anatase TiO_(2) from spent selective catalytic reduction catalyst by Na OH hydrothermal method

The improper disposal of spent selective catalytic reduction (SCR) catalysts causes environmental pollution and metal resource waste.A novel process to recover anatase titanium dioxide (TiO_(2)) from spent SCR catalysts was proposed.The process included alkali (NaOH) hydrothermal treatment,sulfuric acid washing,and calcination.Anatase TiO_(2) in spent SCR catalyst was reconstructed by forming Na_(2)Ti_(2)O_(4)(OH)_(2) nanosheet during NaOH hydrothermal treatment and H_(2)Ti_(2)O_(4)(OH)_(2) during sulfuric acid washing.Anatase TiO_(2) was recovered by decomposing H_(2)Ti_(2)O_(4)(OH)_(2) during calcination.The surface pore properties of the recovered anatase TiO_(2) were adequately improved,and its specific surface area (SSA) and pore volume (PV) were 85 m^(2)·g^(-1)and 0.40 cm^(3)·g^(-1),respectively.The elements affecting catalytic abilities(arsenic and sodium) were also removed.The SCR catalyst was resynthesized using the recovered TiO_(2) as raw material,and its catalytic performance in NO selective reduction was comparable with that of commercial SCR catalyst.This study realized the sustainable recycling of anatase TiO_(2) from spent SCR catalyst.

Toughness enhancement of single-crystal diamond by the homoepitaxial growth of periodic nitrogen-doped nano-multilayers

Periodic nitrogen-doped homoepitaxial nano-multilayers were grown by microwave plasma chemical vapor deposition. The residual time of gases(such as CH4and N2) in the chamber was determined by optical emission spectroscopy to determine the nano-multilayer growth process, and thin, nanoscale nitrogen-doped layers were obtained. The highest toughness of 18.2 MPa·m^(1/2)under a Young’s modulus of1000 GPa is obtained when the single-layer thickness of periodic nitrogen-doped nano-multilayers is about 96 nm. The fracture toughness of periodic nitrogen-doped CVD layer is about 2.1 times that of the HPHT seed substrate. Alternating tensile and compressive stresses are derived from periodic nitrogen doping;hence, the fracture toughness is significantly improved. Single-crystal diamond with a high toughness demonstrates wide application prospects for high-pressure anvils and single-point diamond cutting tools.

Preliminary Evaluation of Hemodynamic Effects of Fontan Palliation on Renal Artery Using Computational Fluid Dynamics

Background:The assessment of renal function is important to the prognosis of patients needing Fontan palliation due to the reconstructed compromised circulation.To know the relationship between the kidney perfusion and hemodynamic characteristics during surgical design could reduce the risk of acute kidney injury(AKI)and the postoperative complications.However,the issue is still unsolved because the current clinical evaluation methods are unable to predict the hemodynamic changes in renal artery(RA).Methods:We reconstructed a three-dimensional(3D)vascular model of a patient requiring Fontan palliation.The technique of computational fluid dynamics(CFD)was utilized to explore the changes of RA hemodynamics under different possible blood flow rates.The relationship between the kidney perfusion and hemodynamic characteristics was investigated.Results:The calculated results indicated the declined tendency of the pressure and pressure drop as the flow rate decreased.When the flow rate decreased to two-thirds of its baseline,both the pressure of left renal artery(LRA)and the pressure of right renal artery(RRA)dipped below 50%,and the pressure of RRA fell more quickly than that of LRA.Uneven distribution of WSS was observed on the trunk of RA,and the lowest WSS was found at the distal of RA.The average WSS in RA dropped to around 50%as the flow rate reached one-third of its baseline.Conclusions:As a promising approach,CFD can be utilized to quantitatively evaluate the hemodynamic characteristics of RA and contribute to offsetting the drawbacks of clinical assessments of renal function,to help realize better prognosis for the patients with Fontan palliation.

Geographical Distribution and Morphological Variability of the Rapid Racerunner,Eremias velox (Pallas,1771)(Reptilia,Lacertidae) in the Eastern Periphery of Its Range

Phenotypic traits are usually correlated with the environment where organism occurs. In this study, the distribution of Eremias velox in the eastern periphery of its range was specified, and its morphological variation was analyzed. Linear dimensions, pholidosis, coloration and pattern features were compared among 135 specimens from nine populations inhabiting the Balkhash, Ili and Alakol basins, Junggar and Turpan depressions in the territory of Southeast Kazakhstan and Xinjiang, Northwest China. The populations from the Junggar Depression(Kuytun, Shihezi and Urumqi) were characterized by higher mean values of linear characters, the number of scales across the middle of the body and gular, and were similar in the dominant coloration patterns. Small size, dark coloration and almost complete dominance of the striped-type coloration pattern among the specimens from the Alakol Lake islands seem to have an adaptive significance associated with the isolation of the population and type of their habitats. The subspecies Eremias velox roborowskii(endemic to the Turpan Depression) is elevated to species level, as supported by morphological divergence congruent with molecular and geographical data, including its peculiar type of coloration pattern, significantly lower amount of femoral pores and a higher percentage of specimens with one enlarged preanal scale(72.7%). These results together confirm a high degree of variability in morphology for E.veloх in the eastern periphery of its range, reflecting a complex orography and the existence of multiple geographical barriers in this territory.

Effects of the electric field at the edge of a substrate to deposit a φ100 mm uniform diamond film in a 2.45 GHz MPCVD system

In this study,uniform diamond films with a diameter of 100 mm were deposited in a 15 kW/2.45 GHz ellipsoidal microwave plasma chemical vapour deposition system.A phenomenological model previously developed by our group was used to simulate the distribution of the electric strength and electron density of plasma.Results indicate that the electric field in the cavity includes multiple modes,i.e.TM_(02) and TM_(03).When the gas pressure exceeds 10 kPa,the electron density of plasma increases and plasma volume decreases.A T-shaped substrate was developed to achieve uniform temperature,and the substrate was suspended in air fromφ70 to 100 mm,thus eliminating vertical heat dissipation.An edge electric field was added to the system after the introduction of the T-shaped substrate.Moreover,the plasma volume in this case was greater than that in the central electric field but smaller than that in the periphery electric field of the TM_(02) mode.This indicates that the electric field above and below the edge benefits the plasma volume rather than the periphery electric field of the TM_(02) mode.The quality,uniformity and surface morphology of the deposited diamond films were primarily investigated to maintain substrate temperature uniformity.When employing the improved substrate,the thickness unevenness of theφ100 mm diamond film decreased from 22%to 7%.

Carbon materials:The burgeoning promise in electronics

Current electronic technology based on silicon is approaching its physical and scientific limits. Carbon-based devices have numer- ous advantages for next generation electronics (e.g., fast speed, low power consumption and simple process), that when combined with the unique nature of the versatile allotropes of carbon elements, are creating an electronics revolution. Carbon electronics are greatly advancing with new preparations and sophisticated designs. In this perspective, representatives with various dimensions, e.g., carbon nanotubes, graphene, bulk diamond, and their extraordinary performance, are reviewed. The associated state-of-the-art devices and composite hybrid all-carbon structures are also emphasized to reveal their potential in the electronics field. Advances in commercial production have improved the cost effi-ciency, material quality, and device design, accelerating the promise of carbon materials.

Effects of Bio-organic Selenium on Agronomic Economic Traits and Selenium Absorption and Distribution in Rice

Under the same conditions of selenium application and application period,different application concentration treatments were set carry out the field plot experiments. The results showed that different treatments had no effect on the growth and development of rice plants;different treatments had an effect on the economic traits of rice; selenium treatment increased the number of filled grains per panicle,seed setting rate and 1 000-grain weight,thus increasing yield; the level of yield was Se4 > Se3 > Se2 > Se1 > Se0; different treatments had a greater effect on the milled rice rate; selenium treatment increased the milled rice rate; the milled rice rate of Se3 and Se4 treatments were 65% and 64%,respectively,which was significantly higher than that of the control group; the general law of selenium absorption of rice was leaf > stem> rice; the selenium content in leaves,stems and rice of different treatments was the highest in Se3 treatment; both the selenium content of rice( total selenium and organic selenium) and the ratio of organic selenium to total selenium in the selenium treatment met the local food safety standard of Hubei Province Selenium content of Selenium-enriched Foods( DBS42/002-2014); selenium-treated rice plants had a high selenium utilization rate,in the range of 51. 26%-64. 12%,exceeding 50%.

Value of partial hepatectomy for the treatment of hilar cholangiocarcinoma: a Meta-analysis study

Objective To discuss the value of partial hepatectomy in patients with hilar cholangiocarcinoma.Methods English articles related to hilar cholangiocarcinoma were screened from January 1,1990 to May 12,2019 in the Pub Med,MEDLINE,EMBASE,and Cochrane Library databases.Information on postoperative radical cure,survival,morbidity,and mortality after surgery were extracted from articles that met the inclusion criteria for the meta-analysis.Results Twenty-two articles that met the inclusion criteria were classified into 4 study groups: the hepatectomy radical cure group(19 articles),the hepatectomy survival group(16 articles),the hepatectomy morbidity group(9 articles),and the hepatectomy mortality group(17 articles).We found that the rate of radical cure after partial hepatectomy(odds ratio [OR] 0.32,95% confidence interval [CI] 0.20-0.51) and the survival rate(hazard ratio [HR] 0.67,95% CI 0.58-0.79) were significantly higher than after simple bile duct resection,but that morbidity(OR 1.99,95% CI 1.37-2.90) and mortality(OR 2.71,95% CI 1.47-4.98) in patients within the partial hepatectomy group were also higher than in the simple bile duct resection group,taking into account the significant heterogeneity in the articles pertaining to the hepatectomy radical cure group(I^2=68.3%,P=0.000),a sub-group analysis was subsequently conducted.Its results showed that when the branches of the secondary bile ducts were not involved during hilar cholangiocarcinoma,then a bile duct resection had a similar radical cure outcome as combined partial hepatectomy(OR 0.94,95% CI 0.54-1.65).Conclusion Partial hepatectomy can increase the proportion of radical cure in patients with hilar cholangiocarcinoma and extend the survival time after surgery.However,the morbidity and mortality after surgery are higher than those in simple bile duct resections.Therefore,simple bile duct resection is still a relevant and efficient tool in the treatment of Bismuth-Corlette Type Ⅰ and Ⅱ hilar cholangiocarcinomas.

Molecular Assessment and Taxonomic Status of the Rapid Racerunner (Eremias velox complex) with Particular Attention to the Populations in Northwestern China

The rapid racerunner,Eremias velox,is a widely distributed lizard from the northern Caucasus across entire Central Asia eastward to China.It is increasingly common to accept E.velox as a species complex in its entire range.To date,published morphological and molecular systematic hypotheses of this complex are only partially congruent,and its taxonomic status and evolutionary history are still far from clear.The mitochondrial cytochrome b gene and12S rRNA sequences were used to evaluate the taxonomy of this complex,with particular attention to the phylogenetic placement of populations in northwestern China.Examination of the phylogenetic analyses recovers seven distinct,biogeographically discrete,and well-supported clades,revealing genetically identifiable populations corresponding to some previously morphology-defined subspecies.Chinese E.v.roborowskii appears to have split from other Central Asian rapid racerunner lizards well before differentiation occurred among the latter taxa.Specifically,we corroborate that there are two subspecies occurring in China,i.e.,E.v.velox and E.v.roborowskii.We recommend a novel subspecific status for the phenotypically and genetically distinct populations in southern Aral Sea region of Uzbekistan previously assigned to E.v.velox.Finally,each of the three independently evolving lineages from Iranian Plateau should be recognized as three species new to science under the general lineage concept.

Engineering transition metal-based nanomaterials for high-performance electrocatalysis

Transition metal(TM)based electrocatalysts attract increasing attention in energy conversion reactions,and current effects focus on material engineering strategies to tailor physicochemical properties of TM based electrocatalysts for improved performance.This review provides a summary about the recent advances of engineering TM based nanomaterials for electrocatalytic reactions,which include hydrogen evolution reaction(HER),oxygen evolution reaction(OER),CO2 reduction reaction(CO2RR),and nitrate reduction reaction(NO3RR).We highlight four engineering strategies,namely,size engineering,facet engineering,composition engineering,and crystal structure engineering for TM based electrocatalysts,and pay a special emphasis on exploring the relationship between their physicochemical properties and catalytic activities.We outline the opportunities in this research field,in particular,the strategy of rationally combining in-situ and operando techniques and theoretical predication to design efficient electrocatalysts.Finally,issues that deserve attention and consideration for practical applications are discussed.

Complete Mitochondrial Genome of the Steppe Ribbon Racer(Psammophis lineolatus):The First Representative from the Snake Family Psammophiidae and its Phylogenetic Implications

Comparisons of vertebrate mitochondrial genomes(mitogenomes)may yield significant insights into the evolution of organisms and genomes.However,no complete mitogenome from the snake family Psammophiidae has been reported.In this study,we sequenced and annotated the complete mitogenome of Psammophis lineolatus,representing the first mitogenome of Psammophiidae.The total length is 17166 bp,consisting of 13 protein-coding genes(PCGs),22 transfer RNAs(tRNAs),two ribosomal RNAs(12 S rRNA and16 S rRNA),and duplicate control regions(CRs).This gene arrangement belongs to the TypeⅢpattern,which is a widely shared gene order in Alethinophidian snakes.All tRNAs exhibit cloverleaf structures with the exception of tRNA-Ser^(AGY) and tRNA-Pro,which lack a dihydrouridine(DHU)arm/stem and TΨC loop,respectively.The 13 PCGs include five start codons(ATG,GTG,ATA,ATT,and ATC),two complete stop codons(TAA and AGG),and two incomplete stop codon(T--and TA-).In addition,the Ka/Ks ratios indicate that all PCGs had undergone a strong purifying selection.Four types of CR domains rearrangement occurred among eight species of Elapoidea.The phylogenetic reconstructions with both Bayesian inference and maximum likelihood methods support the placement of Psammophiidae in the Elapoidea superfamily,with Homalopsidae being the sister taxon to Elapoidea and Colubroidea.However,the sister taxon of Psammophiidae is unclear due to the availability of Elapoidea mitogenomes being limited to the family Elapidae.More mitogenomes from different taxonomic groups in Elapoidea are needed to better understand the phylogenetic relationships within Elapoidea.

Meta-analysis: prognostic value of survivin in patients with pancreatic cancer

Objective： The aim of the study was to conduct a systematic review of the literature evaluating survivin expres- sion in pancreatic carcinoma as a prognostic indicator. Methods： The relevant literatures were searched using PubMed, EMBASE, and Chinese Biomedicine Databases. A meta-analysis of the association between survivin expression and overall survival in patients with pancreatic cancer was performed. Studies were pooled and summary hazard ratios （HRs） were calculated. Subgroup analysis according to the location of survivin expression was also performed. Results： Seven eligible studies with a total of 448 patients were included in this study. Combined HR suggested that survivin expression had an unfavorable impact on survival of pancreatic cancer patients （HR = 1.65, 95% CI： 1.02-2.68）. When stratified according to the location of survivin expression, the combined HR showed that expression in the cytoplasm was significantly associated with poor prog- nosis of pancreatic cancer patients （HR = 2.09, 95% CI： 1.29-3.40）. In contrast, survivin expression in the nucleus was not significantly associated with poor prognosis （HR = 0.83, 95% CI： 0.24-2.81）, and the heterogeneity was highly significant （I2 = 87.2%, P = 0.005）. Conclusien： Survivin expression was associated with a poor prognosis in patients with pancreatic cancer. Cytoplasmic expression of survivin may be a prognostic factor for pancreatic cancer patients. Based on the current obtained data, there was no evidence that survivin expression in the nucleus had a significant impact on patients＇ overall survival.

Safety and efficacy of acute normovolemic hemodilution during liver surgery: a Meta-analysis

Objective The aim of this study was to evaluate the safety and efficacy of acute normovolemic hemodilution(ANH) during liver surgery.Methods Structured searches of the Pub Med,Chinese Biological Medicine Database,and Cochrane Library electronic databases were performed,followed by a meta-analysis of outcomes,including intraoperative blood transfusion(s),intraoperative bleeding,postoperative hematocrit(Hct) levels,postoperative prothrombin time(PT),and number of patients who underwent transfusions during liver surgery.Results In total,14 eligible studies were included in the meta-analysis,which revealed that ANH for liver resection was associated with a reduction in intraoperative blood transfusions [weighted mean difference(WMD)-1.99;95% confidence interval(CI)-2.82 to -1.16;P<0.00001].The ANH group experienced less intraoperative bleeding(WMD -72.81;95% CI -136.12 to -9.50;P<0.00001) and exhibited a lower postoperative Hct level(WMD -3.38;95% CI -7.14 to -0.67;P<0.00001) than the control group.Moreover,meta-analysis revealed that postoperative prothrombin time was not affected by ANH(WMD -0.02;95% CI -0.18 to -0.32;P=0.65).Finally,the number of patients requiring allogeneic transfusion was significantly smaller in the ANH group than in the control group(odds ratio 0.13;95% CI 0.09 to 0.18;P=0.24).Conclusion Results of the present meta-analysis indicated that ANH can reduce intraoperative bleeding and the need for blood transfusions.In addition,ANH did not negatively affect the coagulation system after surgery;therefore,ANH appears to be safe and effective during liver surgery.

Dynamic Performance Analysis of Steel Frame Structure under Seismic Action

In order to find out the dynamic characteristics of a steel frame structure project in the 8 degree (0.3g) area, the artificial wave, Taft wave and El Centro wave were input by using the finite element analysis software ANSYS. The dynamic time-history analysis of the structure shows the dynamic performance of the structure under the frequent earthquakes and rare earthquakes.

M2 macrophage-derived exosomes promote diabetic fracture healing by acting as an immunomodulator

Diabetes mellitus is a chronically inflamed disease that predisposes to delayed fracture healing.Macrophages play a key role in the process of fracture healing by undergoing polarization into either M1 or M2 subtypes,which respectively exhibit pro-inflammatory or anti-inflammatory functions.Therefore,modulation of macrophage polarization to the M2 subtype is beneficial for fracture healing.Exosomes perform an important role in improving the osteoimmune microenvironment due to their extremely low immunogenicity and high bioactivity.In this study,we extracted the M2-exosomes and used them to intervene the bone repair in diabetic fractures.The results showed that M2-exosomes significantly modulate the osteoimmune microenvironment by decreasing the proportion of M1 macrophages,thereby accelerating diabetic fracture healing.We further confirmed that M2-exosomes induced the conversion of M1 macrophages into M2 macrophages by stimulating the PI3K/AKT pathway.Our study offers a fresh perspective and a potential therapeutic approach for M2-exosomes to improve diabetic fracture healing.

会阴部动静脉畸形误诊为会阴疝二例

动静脉畸形,也称蔓状血管瘤,是一种高流量的先天性血管畸形,由扩张的动脉和静脉组成,异常的动静脉之间缺乏正常毛细血管床[1]。本病最常见的发病部位是颅脑,其次依序为头部、颈部、四肢、躯干和内脏器官[2]。会阴部发病者临床罕见,且因部位的特殊性,瘤体可因腹压增大盆底下降而突出,腹压减小盆底相对上升而回缩,从而具有可复性肿物的临床表现,容易被误诊为会阴疝[3]。现将北京中医药大学东直门医院收治的2例误诊为会阴疝的会阴部动静脉畸形报道如下。

Si nanowire Bio-FET for electrical and label-free detection of cancer cell-derived exosomes

Exosomes are highly important in clinical diagnosis due to their high homology with their parental cells.However,conventional exosome detection methods still face the challenges of expensive equipment,low sensitivity,and complex procedures.Field effect transistors(FETs)are not only the most essential electronic component in the modern microelectronics industry but also show great potential for biomolecule detection owing to the advantages of rapid response,high sensitivity,and label-free detection.In this study,we proposed a Si nanowire field-effect transistor(Si-NW Bio-FET)device chemically modified with specific antibodies for the electrical and label-free detection of exosomes.The Si-NW FETs were fabricated by standard microelectronic processes with 45 nm width nanowires and packaged in a polydimethylsiloxane(PDMS)microfluidic channel.The nanowires were further modified with the specific CD63 antibody to form a Si-NW Bio-FET.The use of the developed Si-NW Bio-FET for the electrical and labelfree detection of exosomes was successfully demonstrated with a limit of detection(LOD)of 2159 particles/mL.In contrast to other technologies,in this study,Si-NW Bio-FET provides a unique strategy for directly quantifying and realtime detecting exosomes without labeling,indicating its potential as a tool for the early diagnosis of cancer.

Chemical vapor deposited diamond with versatile grades:from gemstone to quantum electronics

Chemical vapor deposited(CVD)diamond as a burgeoning multifunctional material with tailored quality and characteristics can be artificially synthesized and controlled for various applications.Correspondingly,the application-related“grade”concept associated with materials choice and design was gradually formulated,of which the availability and the performance are optimally suited.In this review,the explicit diversity of CVD diamond and the clarification of typical grades for applications,i.e.,from resplendent gem-grade to promising quantum-grade,were systematically summarized and discussed,according to the crystal quality and main consideration of ubiquitous nitrogen impurity content as well as major applications.Realizations of those,from quantum-grade with near-ideal crystal to electronic-grade having extremely low imperfections and then to optical,thermal as well as mechanical-grade needing controlled flaws and allowable impurities,would competently fulfill the multi-field application prospects with appropriate choice in terms of cost and quality.Exceptionally,wide range defects and impurities in the gem-grade diamond(only indicating single crystal),which are detrimental for technology applications,endows CVD crystals with fancy colors to challenge their natural counterparts.