Recent progress in graphene-based wearable piezoresistive sensors:From 1D to 3D device geometries

Electronic skin and flexible wearable devices have attracted tremendous attention in the fields of human-machine interaction,energy storage,and intelligent robots.As a prevailing flexible pressure sensor with high performance,the piezoresistive sensor is believed to be one of the fundamental components of intelligent tactile skin.Furthermore,graphene can be used as a building block for highly flexible and wearable piezoresistive sensors owing to its light weight,high electrical conductivity,and excellent mechanical.This review provides a comprehensive summary of recent advances in graphene-based piezoresistive sensors,which we systematically classify as various configurations including one-dimensional fiber,two-dimensional thin film,and threedimensional foam geometries,followed by examples of practical applications for health monitoring,human motion sensing,multifunctional sensing,and system integration.We also present the sensing mechanisms and evaluation parameters of piezoresistive sensors.This review delivers broad insights on existing graphene-based piezoresistive sensors and challenges for the future generation of high-performance,multifunctional sensors in various applications.

不同水平呼气末正压对新生儿急性呼吸窘迫综合征的疗效及血流动力学的影响

目的探究不同水平呼气末正压(PEEP)治疗新生儿急性呼吸窘迫综合征(ARDS)的疗效及其血流动力学影响。方法选取2017年3月—2019年5月天津市中心妇产科医院收治的112例ARDS新生儿。根据通气的不同分为研究组和对照组,研究组58例患儿接受高水平PEEP(6~<9 cm H2O)治疗,对照组54例患儿接受低水平PEEP(3~<6 cm H2O)治疗。观察两组患者治疗前及治疗稳定后24 h的心率(HR)、平均肺动脉压(MPAP)、中心静脉压(CVP)、pH值、动脉血二氧化碳分压(PaCO2)、氧合指数(OI)水平、气道阻力(Raw)、呼吸系统顺应性(Crs)。观察两组患者的机械通气时间、住院时间、死亡例数。结果研究组HR、MPAP降低的差值,以及CVP升高的差值均高于对照组(P<0.05);研究组pH值、OI升高的差值,以及PaCO2降低的差值均高于对照组(P<0.05);研究组Raw降低的差值及Crs升高的差值均高于对照组(P<0.05)。研究组机械通气时间、住院时间均短于对照组(P<0.05);研究组死亡率低于对照组(P<0.05)。结论高水平PEEP对新生儿血流动力学指标的改善作用更明显,对气体交换和呼吸力学的影响更大,能有效减少机械通气时间及住院时间,降低病死率。

Effect of blocking IGF-I receptor on growth of human hepatocellular carcinoma cells

AIM: To study the expression level and localization of insulin-like growth factor -I receptor (IGF-IR) in HepG2 cells and Chang liver cells, and to observe the effect of anti-IGF-IR monoclonal antibody (αIR3) on the growth of HepG2 cells. METHODS: The expression of IGF-IR in HepG2 cells and Chang liver cells was detected by immunohistochemistry. The influences of aIR3 on proliferation and apoptosis were examined by the 3- (4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and electron microscopy, respectively. Flow cytometry (FCM) was applied for the analysis of cell cycle and apoptosis was observed under electron microscope. RESULTS: IGF-IR was located in the membranes of both HepG2 and Chang liver cell lines, and the expression level of IGF-IR was higher in HepG2 cells than in Chang liver cells. Treated with 0.1μg/mLαIR3 for 48 h in vitro, the cell growth index (GI) of HepG2 cells was significantly higher than that of control (103.41% vs 100%, P<0.01). However, the aIR3 for 24 h at final concentration of 4.0μg/mL made the GI of HepG2 cells lower than that of control (93.37% vs 100%, P < 0.01). Compared with control, treated with aIR3 for 48 h at final concentrations ranging from 1.0μg/mL to 4.0μg/mL markedly reduced the GIs of HepG2 cells (97.63%, 97.16%, 95.13%, 92.53% vs 100%, P < 0.05 or P < 0.01), treated withαIR3 for 72 h at final concentrations ranging from 0.2μg/mL to 4.0μg/mL decreased the GIs of HepG2 cells obviously (95%, 91.63%, 90.77%, 89.84%, 88.51% vs 100%, P<0.01), and treated with aIR3 for 96 h at final concentrations ranging from 0.5μg/mL to 4.0μg/mL made GIs of HepG2 cells lower significantly (88.86%, 83.97%, 79.81%, 77.24%, 70.51% vs 100%, P<0.05 or P<0.01). Moreover, treated withαIR3 from 24 h to 96 h at final concentrations ranging from 0.2μg/mL to 4.0μg/mL reduced the GI of HepG2 cells from 97.63% to 70.51% in a dose- and time-dependent manner. Also,αIR3 treatment for 72 h at final concentration from 0.5μg/mL to 2.0μg/mL increased the proportion of G0/G1 phase cells(61.73%, 67.1%, 83.7%,76.87% vs 44.47%, P<0.01) and significantly decreased that of S phase cells(28.63%, 25.13%, 15.63%, 23.13% vs 53.17%, P<0.01), in contrast to the proportion of G2/M phase cells. The apoptotic rates of HepG2 cells were increased more than that of control (7.83%, 16.13%, 21.1%, 37.73% vs 4.13%, P< 0.01). CONCLUSION: The malignant cell phenotype of human hepatocarcinoma cell is related to overexpression of IGF-IR. The blockage of IGF-IR with aaaaaIR3 may contribute to the inhibition of proliferation and induction of apoptosis in HepG2 cells.

Endoscopic pancreaticobiliary drainage with overlength stents to prevent delayed perforation after endoscopic papillectomy:A pilot study

BACKGROUND Endoscopic papillectomy(EP)is rapidly replacing traditional surgical resection and is a less invasive procedure for the treatment of duodenal papillary tumors in selected patients.With the expansion of indications,concerns regarding EP include not only technical difficulties,but also the risk of complications,especially delayed duodenal perforation.Delayed perforation after EP is a rare but fatal complication.Exposure of the artificial ulcer to bile and pancreatic juice is considered to be one of the causes of delayed perforation after EP.Draining bile and pancreatic juice away from the wound may help to prevent delayed perforation.AIM To evaluate the feasibility and safety of placing overlength biliary and pancreatic stents after EP.METHODS This is a single-center,retrospective study.Five patients with exposure or injury of the muscularis propria after EP were included.A 7-Fr overlength biliary stent and a 7-Fr overlength pancreatic stent,modified by an endoscopic nasobiliary drainage tube,were placed in the common bile duct and pancreatic duct,respectively,and the bile and pancreatic juice were drained to the proximal jejunum.RESULTS EP and overlength stents placement were technically feasible in all five patients(63±12 years),with an average operative time of 63.0±5.6 min.Of the five lesions(median size 20 mm,range 15-35 mm),four achieved en bloc excision and curative resection.The final histopathological diagnoses of the endoscopic specimen were one tubular adenoma with high-grade dysplasia(HGD),one tubulovillous adenoma with low-grade dysplasia,one hamartomatous polyp with HGD,one poorly differentiated adenocarcinoma and one atypical juvenile polyposis with tubulovillous adenoma,HGD and field cancerization invading the muscularis mucosae and submucosa.There were no stent-related complications,but one papillectomy-related complication(mild acute pancreatitis)occurred without any episodes of bleeding,perforation,cholangitis or late-onset duct stenosis.CONCLUSION For patients with exposure or injury of the muscularis propria after EP,the placement of overlength biliary and pancreatic stents is a feasible and useful technique to prevent delayed perforation.

Comparison of hepatic resection and transarterial chemoembolization for solitary hepatocellular carcinoma

AIM: To compare the outcomes of hepatic resection and transarterial chemoembolization(TACE) for solitary hepatocellular carcinoma(HCC) according to the Barcelona Clinic Liver Cancer(BCLC) staging system.METHODS: A consecutive sample of 540 patients with solitary HCC who underwent liver resection(n = 312) or TACE(n = 128) were included in the present study. Baseline characteristics, tumor characteristics, and post-operative complications were compared between the two groups. The Kaplan-Meier method was used for long-term survival analysis. Independent prognostic predictors were identified using the Cox proportional hazards model(univariate and multivariate analyses).RESULTS: The TACE and liver resection groups had similar baseline demographic and clinicopathological characteristics. The TACE group showed a significantly lower rate of major complications than the liver resection group(3.9% vs 17.4%, P < 0.001). Univariate and multivariate analyses indicated that TACE did not contribute to poor overall survival compared with liver resection; however, a solitary tumor diameter of greater than 6 cm should be considered a risk factor for poor overall survival(HR = 1.328, 95%CI: 1.002-1.783, P = 0.048). The liver resection and TACE groups had comparable overall survival rates at 1 year, 3 years, and 5 years(86.2%, 62.8%, and 44.0% vs 88.3%, 59.8%, and 40.6%, respectively, P = 0.419). In cases with tumor diameters equal to or less than 6 cm, the liver resection group showed a survival benefit compared with the TACE group at 1 year, 3 years, and 5 years(P = 0.030). The 1-, 3-, and 5-year overall survival rates of HCC cases with tumor diameters ofmore than 6 cm were similar among the liver resection and TACE groups(P = 0.467).CONCLUSION: A tumor diameter of 6 cm should be the cutoff for deciding between liver resection and TACE.

ABCD评分系统在短暂性脑缺血发作病人早期发生脑卒中风险的预测

目的:进一步明确基于中国人群的短暂性脑缺血发作(transient ischemic attack,TIA)病人,3种ABCD评分系统预测TIA发作后7 d内发生新发脑梗死风险的临床应用价值。方法:150例TIA病人于入院48 h内采用ABCD2、ABCD3、ABCD3-Ⅰ3种评分系统,根据评分分为低危、中危及高危组;根据病人TIA发作后7 d内是否继发脑梗死分为新发脑梗死组和非脑梗死组,比较2组TIA病人的3种评分系统评分;记录3种评分的低、中、高危组中TIA后7 d内继发脑梗死病人例数。结果:与非脑梗死组比较,新发脑梗死组的3种不同的ABCD系统的评分结果均升高,差异具有统计学意义(P<0.05～P<0.01);除ABCD2评分外,随着ABCD3、ABCD3-Ⅰ评分分值的升高,7 d内继发脑梗死率不断增加(P<0.01);ROC曲线分析发现,3种ABCD评分系统对7 d内继发脑梗死的预测AUC分别为0.67、0.84和0.91,均大于基准线面积的0.5,差异有统计学意义(P<0.01)。ABCD3-Ⅰ预测7 d内继发脑梗死准确度优于ABCD3,ABCD3优于ABCD2,差异具有统计学意义(P<0.01)。结论:3种ABCD评分方法均能预测TIA后7 d内继发的新发脑梗死,分值越高,7 d内继发新发脑梗死的危险度越高,ABCD3-Ⅰ预测准确度最高。

Magnetic resonance imaging findings for differential diagnosis of perianal plexiform schwannoma: Case report and review of the literature

Plexiform schwannoma is an extremely rare variant of schwannoma, accounting for approximately 5% of cases. Due to the rarity and lack of typical symptoms, signs and radiological images, a definite diagnosis of plexiform schwannoma may not be made by clinicians prior to biopsy. In the present study, we report the first case(to our knowledge) of perianal plexiform schwannoma arising from the overlapped skin of the ischioanal fossa, and we propose an intratumorally nonenhanced circumferential capsule dividing the tumour into multiple homogeneously enhanced nodules as a magnetic resonance imaging feature to aid in the differential diagnosis of plexiform schwannoma from ancient schwannoma, cavernous haemangioma, liposarcoma and plexiform neurofibroma.

Effect of heat treatment and thermomechanical processing on microstructure and tensile property of Ti-44Al-8Nb-0.2W-0.2B-0.5Y alloy

High Nb-TiAl (Ti-44Al-8Nb-0.2W-0.2B-0.5Y,at.%) ingot was fabricated by vacuum arc remelting (VAR).The as-cast ingot was hot-isostatic pressed (HIP) and homogenizing annealing processed.The influence of heat treatment temperature and thermomechanical processing on the microstructure and tensile property of the alloy was investigated by X-ray diffractometry (XRD),scanning electron microscopy (SEM) and tensile tests.It was found that the high Nb-TiAl alloy after HIP and annealing was mainly composed of coarse α2/γ lamellae,β/B2 phase and γ phase and the solidification path of this alloy was:L→L+β→β→α+β→α→α+β+γ→α2+β+γ.The water quenching results showed that the alloy was in α single phase region at 1,340 °C.After heating at 1,340 °C for 30 min followed by furnace cooling,the alloy showed a full lamellar microstructure and its ultimate tensile strength was about 538 MPa,with an elongation of 0.3% at room temperature.Free-crack forged pancakes with fine-grained fully lamellar structure (FFLS) were obtained with an initial deformation temperature of 1,340 °C and the ultimate tensile strength of forged alloy was about 820 MPa,with an elongation of 0.9% at room temperature,which was much higher than that of alloy after HIP and annealing because of microstructural refinement.

Study on multi-target mechanism of Radix et Rhizoma Rhei (Dahuang) and Semen Persicae (Taoren) on adhesion intestinal obstruction based on network pharmacology

Objective: To explore the mechanism of action of Radix et Rhizoma Rhei (Dahuang)(RERR) and Semen Persicae (Taoren)(SP) on adhesive intestinal obstruction (AIO). Methods: The main targets of the active ingredients of RERR and SP were filtered based on the traditional Chinese medicine system pharmacology analysis platform. Cytoscape 3.2.1 was applied to build the ingredient-target network of RERR and SP for AIO. Results: Fifteen active components were predicted from the RERR and SP herb pair, such as aloe-emodin, catechin, rhein, gibberellin (GA) 119, GA120 and GA121. These components were applied to 59 targets mainly involved in many biological processes such as signal transduction, anti-apoptosis, and inflammatory response involved in activating the immune effect. Conclusion: This study proposes the system pharmacology method and identifies the potent combination therapeutic mechanism of RERR and SP for AIO. This strategy will provide a new insight to the study of herb combinations.

Interactions between Ti Al alloy and AZC/AMT binder systems in investment casting

In this work, two kinds of binders, Ammonium Zirconium Carbonate(AZC) and Ammonium Metatungstate(AMT) hydrate, and three kinds of powders(ZrO 2, Al2O3 and Y2O3) were mixed to fabricate six kinds of face coating systems. The thermal behaviors of the AZC and AMT dried binders were investigated by TG-DTA, and the phase transformation of the two binders was determined by XRD. Monoclinic ZrO 2 phase was formed from AZC at 620 °C and WO3 at 700 °C, and the phase transformation was completed at lower than 1000 °C in both binders, and therefore, the sintering temperature for the molds was selected at 950 °C. The interaction between the ceramic molds with different face coatings and the Ti-48Al-2Cr-2Nb alloy during investment casting was studied. Results showed no α-case reaction in the TiA l-mold reaction, and the AMT + Y2O3 face coating appeared to be the best choice for investment casting of TiA l alloys under the experimental conditions.

Noble metal-based high-entropy alloys as advanced electrocatalysts for energy conversion

Noble metal-based high-entropy alloy nanoparticles(NM-HEA NPs) have exhibited brilliant catalytic performance toward electrocatalytic energy conversion and attracted increasing attention. The near-equimolar mixed elements of NM-HEA NPs may result in the unique properties including cocktail effect, high entropy effect and lattice distortion effect, which are beneficial for improving the catalytic performance and reducing the amount of noble metal. Herein, several advanced NM-HEA NPs as electrocatalysts for energy conversion are systematically summarized. The preparation methods of NM-HEA NPs are evaluated as well as the catalytic properties and mechanism are discussed classified by electrocatalytic reactions. Finally,the challenges and prospects in this field are carefully discussed. This review provides an overview on recent advances of NM-HEA electrocatalysts for energy conversion and draws more attention in this infant research field.

Microstructure characterization and tensile properties of a Ni-containing TiAl-based alloy with heat treatment

The effects of Ni addition on solidification micro structure and tensile properties of Ti-48Al-2Cr-2Nb alloy were investigated using differential scanning calorimetry（DSC）,X-ray diffraction（XRD）,scanning electron microscopy（SEM） equipped with energy-dispersive spectroscope（EDS） and transmission electron microscopy（TEM）.Results show that with 3 at%Ni addition,the as-cast micro structure is mainly composed of fine lamellar colonies（~50 μm）,γ grains and Ni-ridied τ_3 phase.After heat treatment at 1380℃,the Ni-containing alloy is characterized by fine fully lamellar micro structure（~90 μm）.The heat-treated Ni-containing specimen exhibits superior room temperature tensile properties than other specimens.The tensile properties are discussed in light of the microstructure evolution and role of Ni-riched τ_3 phase.

Suppressive effect of Aurantii Fructus Immaturus and Atractylodis Macrocephalae Rhizoma on glutamic acid-induced autophagy of interstitial cells of Cajal

Objective:To investigate the effects of Aurantii Fructus Immaturus(Zhishi,ZS)and Atractylodis Macrocephalae Rhizoma(Baizhu,BZ)-containing serum on glutamate-induced autophagy in rat colonic interstitial cells of Cajal(ICCs)and to analyze the underlying mechanism.Methods:Rat colonic ICCs cultured in vitro were identified by fluorescence and then stimulated with glutamic acid(5 mmol/L)for 24 h to establish a cell model of autophagy.The cells were then treated with different concentrations of ZSBZ-containing serum or rat serum.The viability of the ICCs was detected with cell counting kit-8 assays,and cell apoptosis rates were examined with flow cytometry.The ultrastructure and autophagosomes in the ICCs were observed using transmission electron microscopy.The effects of ZSBZ-containing serum on apoptosis-associated mediators were assessed by Western blotting and real-time quantitative polymerase chain reaction.In addition,microtubule-associated protein light chain 3(LC3),p-phosphoinositide 3-kinase(p-PI3 K),p-Akt and p-mammalian target of rapamycin(pm TOR)expression was detected via Western blotting analysis.Results:Compared to those in the model group,ICC viability and apoptosis rates were significantly increased by ZSBZ-containing serum(P<0.05).In addition,the expression levels of Beclin-1,LC3,pPI3 K,p-Akt and p-mTOR were significantly lower(P<0.05)and Bcl-2 expression was higher in the ZSBZ-containing serum treatment groups than in the model group(P<0.05).Conclusion:Our findings demonstrated that ZSBZ protects glutamic acid-stimulated ICCs,and this beneficial effect may be mediated by a reduction in autophagy via inhibition of the PI3 K/Akt/mTOR pathway.

Microstructure and properties of a beta-solidifying TiAl-based alloy with different refiners

This study systematically compared the influences of yttrium（Y）,boron（B）,and carbon（C） on the microstructural refinement and properties of a Ti-43Al-5Nb alloy.The microstructural refinement effect in the TiAl alloy closely depends on the refiner used.The refinement effects of the three elements on colony size and lamellar thickness can be arranged as B 〉 Y 〉 C and Y 〉 C 〉 B,respectively.Moreover,a microstructure with a small grain size and ultra-fine lamellar spacing can be obtained by adding B and Y or B and C.The mechanical properties of TiAl alloy are also influenced by the refiners.TiAl alloys with proper B and Y contents exhibit favorable hot workability,tensile properties,and fracture toughness,whereas the C-containing alloy displays poor tensile properties and low fracture toughness.These results indicate that Y and B are more suitable microstructure refiners than C.This study may serve as a reference for practical alloying design.

Microstructure evolution of Ti–46Al–6Nb–(Si,B) alloys during heat treatment with W addition

The cast ingots of Ti-46Al-6Nb-0.25Si-0.2B and Ti-46Al-6Nb-0.5W-0.25Si-0.2B（at%） were made by induction skull melting（ISM） technique.A series of heat treatments（HTs） were conducted to research the microstructure evolution of both alloys.Microstructure and tensile property were examined by scanning electron microscope（SEM）,X-ray diffraction（XRD）,transmission electron microscope（TEM）,and tensile testing machine.The results show that microsegregation（liquid segregation and solid segregation） is exacerbated by the addition of0.5 at%W;the addition of Nb,W in TiAl alloy makes the phase transition difficultly take place;then,the microstructures and tensile properties of both alloys are improved after certain HT processes;finally,the thicknesses of the γ/α_2 lamellae after a certain HT process are significantly affected by the number of residual γ phases before the furnace-cooling moment.

Microstructure and high-temperature tensile property of TiAl alloy produced by selective electron beam melting

The microstructure and high-temperature tensile property of a Ti-47Al-2Cr-2 Nb alloy fabricated via selective electron beam melting(SEBM) with hatch spacings of 85,100,and 115 μm were systematically investigated.When the hatch spacing increased from 85 to 115 μm,the microstructure comprising the horizontal cross section changed from coarse lamellar(y/B2) colonies to an inhomogeneous structure and the grain morphology transformed from elongated grains to inhomogeneous and equiaxed grains along the building direction of the vertical cross section.The boundary population of the SEBMproduced TiAl alloy samples was dominated by high-angle grain boundaries(≥ 15°),and the volume fraction of these boundaries decreased with hatch spacing increasing.Additionally,the as-built TiAl alloy sample produced under a spacing of 100 μm exhibited the highest room-and elevated-temperature tensile strengths,with the ultimate tensile strength at room temperature(642 MPa) increasing to 674 MPa at 700 ℃.Furthermore,the mechanism of anomalous strengthening at 700 ℃ was discussed in detail.

Dual-modal Physiological Feature Fusion-based Sleep Recognition Using CFS and RF Algorithm

Research has demonstrated a significant overlap between sleep issues and other medical conditions.In this paper,we consider mild difficulty in falling asleep(MDFA).Recognition of MDFA has the potential to assist in the provision of appropriate treatment plans for both sleep issues and related medical conditions.An issue in the diagnosis of MDFA lies in subjectivity.To address this issue,a decision support tool based on dual-modal physiological feature fusion which is able to automatically identify MDFA is proposed in this study.Special attention is given to the problem of how to extract candidate features and fuse dual-modal features.Following the identification of the optimal feature set,this study considers the correlations between each feature and class and evaluates correlations between the inter-modality features.Finally,the recognition accuracy was measured using 10-fold cross validation.The experimental results for our method demonstrate improved performance.The highest recognition rate of MDFA using the optimal feature set can reach 96.22%.Based on the results of current study,the authors will,in projected future research,develop a real-time MDFA recognition system.

Exclusive vector meson production with the analytical solution of Balitsky-Kovchegov equation

Exclusive vector meson production is an excellent probe for describing the structure of protons.In this study,based on the dipole model,the differential cross sections,total cross sections,and ratios of the longitudinal to transverse cross section of the J/ψandρ^(0)productions are calculated with the analytical solution of the Balitsky-Kovchegov(BK)equation.In addition,we consider the influences of two meson wave function models on the results.Our predictions,which are slightly sensitive to meson wave functions,agree with the experimental data.The analytical solution of the BK equation is reliable for description of exclusive vector meson productions in a certain range of Q^(2).