outcomes of preoperative endoscopic nasobiliary drainage and endoscopic retrograde biliary drainage for malignant distal biliary obstruction prior to pancreaticoduodenectomy

AIM to compare the outcomes of preoperative endoscopic nasobiliary drainage (ENBD) and endoscopic retrograde biliary drainage (ERBD) in patients with malignant distal biliary obstruction prior to pancreaticoduodenectomy (PD). METHODS Data from 153 consecutive patients who underwent preoperative endoscopic biliary drainage prior to PD between January 2009 and July 2016 were analyzed. We compared the clinical data, procedure-related complications of endoscopic biliary drainage (EBD) and postoperative complications of PD between the ENBD and ERBD groups. Univariate and multivariate analyses with odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to identify the risk factors for deep abdominal infection after PD. RESULTS One hundred and two (66.7%) patients underwent ENBD, and 51 (33.3%) patients underwent ERBD. Endoscopic sphincterotomy was less frequently performed in the ENBD group than in the ERBD group (P = 0.039); the EBD duration in the ENBD group was shorter than that in the ERBD group (P = 0.036). After EBD, the levels of total bilirubin (TB) and alanine aminotransferase (ALT) were obviously decreased in both groups, and the decreases of TB and ALT in the ERBD group were greater than those in the ENBD group (P = 0.004 and P = 0.000, respectively). However, the rate of EBD procedure-related cholangitis was significantly higher in the ERBD group than in the ENBD group (P = 0.007). The postoperative complications of PD as graded by the Clavien-Dindo classification system were not significantly different between the two groups (P = 0.864). However, the incidence of deep abdominal infection after PD was significantly lower in the ENBD group than in the ERBD group (P = 0.019). Male gender (OR = 3.92; 95% CI: 1.63-9.47; P = 0.002), soft pancreas texture (OR = 3.60; 95% CI: 1.37-9.49; P = 0.009), length of biliary stricture (= 1.5 cm) (OR = 5.20; 95% CI: 2.23-12.16; P = 0.000) and ERBD method (OR = 4.08; 95% CI: 1.69-9.87; P = 0.002) were independent risk factors for deep abdominal infection after PD. CONCLUSION ENBD is an optimal method for patients with malignant distal biliary obstruction prior to PD. ERBD is superior to ENBD in terms of patient tolerance and the effect of biliary drainage but is associated with an increased risk of EBD procedure-related cholangitis and deep abdominal infection after PD. (C) The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.

Effect of solid solution treatment on in vitro degradation rate of as-extruded Mg-Zn-Ag alloys

The degradation behaviors of the as-extruded and solution treated Mg-3Zn-xAg(x=0,1,3,mass fraction,%)alloys,as well as as-extruded pure Mg,have been investigated by immersion tests in simulated body fluid(SBF)at37°C.The as-extruded Mg-Zn(-Ag)alloys contained Mg51Zn20and Ag17Mg54.While the quasi-single phase Mg-Zn(-Ag)alloys were obtained by solution treatment at400°C for8h.The quasi-single phase Mg-Zn(-Ag)alloys showed lower degradation rate and more homogeneous degradation than corresponding as-extruded Mg alloys.Degradation rate of solid-solution treated Mg-3Zn-1Ag and Mg-3Zn-3Ag was approximately half that of corresponding as-extruded Mg alloy.Moreover,the degradation rate of solid-solution treated Mg-3Zn and Mg-3Zn-1Ag was equivalent to that of as-extruded pure Mg.However,heterogeneous degradation also occurred in quasi-single phase Mg-Zn-Ag alloys,compared to pure Mg.So,preparing complete single-phase Mg alloys could be a potential and feasible way to improve the corrosion resistance.

Metabolic syndrome risk factors and dry eye syndrome:a Meta-analysis

AIM：To explore the relationship between metabolic risk factors and dry eye syndrome（DES）.METHODS：Retrieved studies on the association of metabolic syndrome risk factors（hypertension,hyperglycemia,obesity,and hyperlipidemia） and DES were collected from PubMed,Web of Science,and the Cochrane Library in December 2015.Odds ratio（OR） with 95% confidence interval（Cl） were pooled to evaluate the final relationship.Subgroup analyses were conducted according to diagnostic criteria of DES.RESULTS：Nine cross-sectional studies and three case-control studies were included in this Meta-analysis.The pooled results showed that people with hypertension,hyperglycemia,and hyperlipidemia had a higher risk of suffering from DES（P〈0.05）,especially the typical DES symptoms.On the other hand,obesity did not increase the risk of DES.CONCLUSION：The present Meta-analysis suggests that all metabolic risk factors except obesity were risk factors for DES.

Inter-granular exchange coupling and magnetic anisotropy of Ta/Ru/Co-23 at%Pt perpendicular thin films with different Ru underlayer thicknesses

In the present work, a series of Ta/Ru/Co- 23 at%Pt thin films with varied Ru underlayer thicknesses were fabricated by magnetron sputtering. All of the films show c-axis preferred orientation perpendicular to the film surface. The drop of c/a ratio and lattice expansion of Co- Pt layer with the increase in Ru underlayer thickness was revealed by X-ray diffraction （XRD）. The coercivity of the Ta/Ru/Co-Pt thin films increases drastically with Ru underlayer thickness increasing, due to the enhancement of effective magneto-crystalline anisotropy constant and exchange decoupling of magnetic nano-grains. The enhancement of effective magneto-crystalline anisotropy constant is ascribed to the lattice deformation of Co-Pt layer by mismatching the Ru layer and Co-Pt surface. Moreover, the exchange decoupling of magnetic nanograins is attributed to the further isolation of magnetic nano-grains.

Microstructures and bio-corrosion resistances of as-extruded Mg-Ca alloys with ultra-fine grain size

Electrochemical and immersion tests were conducted to characterize the bio-corrosion resistance of asextruded Mg-Ca binary alloys with submicron grain size.The microstructures were further characterized by optical microscopy(OM),scanning electronic microscopy and transmission electron microscope(TEM).The grain size was estimated from OM and TEM images.Three samples and at least 20 images were used to evaluate the average grain size.Macro-textures of the as-extruded samples were measured via X-ray diffraction.The Mg-2Cu alloy extruded at 300℃(2Ca-300)exhibits the lowest current density of 1.683 mA·cm^(-2)and corrosion rate of 22.14 g·m^(-2)·day^(-1)in simulated body fluid,which is comparable with that of pure Mg.The Ca addition can reduce grain size of as-extruded Mg alloy and decrease the corrosion rate.The formed Mg2Ca phases would accelerate the local galvanic corrosion and protect theα-Mg matrix simultaneously due to the lower electrode potential.The lower defect density,finer grain size and weaker basal texture intensity contribute to the excellent bi-corrosion resistance of the 2Ca-300 alloy.

Microstructure,Mechanical Properties and Fracture Behavior of As-Extruded Zn-Mg Binary Alloys

In the present work, Zn-（0-1）Mg（wt%） alloys were prepared by casting and indirect extrusion at 200 and300 ℃, respectively. With Mg addition, both the size and amount of second phase Mg2Zn（11） increased, and the equiaxed grains were significantly refined. The extrusion temperature had little influence on Mg2Zn（11）, but the grains were refined at low extrusion temperature. For the alloys extruded at 200 ℃, as Mg content increased, the tensile yield strength（TYS）increased from 64 MPa for pure Zn to 262 MPa for Zn-1Mg; the elongation increased from 14.3% for pure Zn to 25% for Zn-0.02Mg and then decreased to 5% for Zn-1Mg. For the alloys extruded at 300 ℃, as Mg content increased, the TYS increased from 67 MPa for pure Zn to 252 MPa for Zn-1Mg, while the elongation decreased from 11.7% to 2%. The alloy extruded at 200 ℃ exhibited higher TYS and elongation than the corresponding alloy extruded at 300 ℃. The combination of grain refinement and second phase Mg2Zn（11） contributed to the improvement in the TYS, and the grain refinement played a major role in strengthening alloy. Zn-0.02Mg and Zn-0.05Mg alloys extruded at 200 ℃ show a mixture of cleavage and ductile fracture corresponding to higher elongation, while the other alloys show cleavage fracture.

Phase equilibria of low-Y side in Mg-Zn-Y system at 400℃

Phase equilibrium relations of the Mg-Zn-Y system in the low-Y side at 400℃were investigated by alloy-equilibrated method,combined with thermal analysis.The results show that there is a liquid phase which could be in equilibrium with an a-Mg solid solution and an icosahedral quasicrystal I phase in the low-Y side of the Mg-Zn-Y system at 400℃.The liquid phase region originates from the binary Mg-Zn system and extends to 0.4 at%Y in the Mg-Zn-Y system.Besides,the hexagonal structure H phase,fee W phase and LPSO phase(X phase)are in equilibrium with a-Mg.With Y/Zn(atomic ratio,the same as follows)increasing,there exist four three-phase regions consisting of I+liquid+α-Mg,I+H+α-Mg,H+W+α-Mg and W+X+α-Mg,respectively,in the low-Y side of the isothermal section at 400℃.The twophase region a-Mg+I phase exists between I+H+aMg and I+liquid+a-Mg.In this two-phase region,the Y/Zn ratio is in the range of 0.14-0.17;and a three-phase region of a-Mg+I phase+H phase appears when Y/Zn ratio comes up to 0.17-0.27.Not I but W phase is in equilibrium with a-Mg,when Y/Zn ratio>0.27.The system is in liquid-state phase equilibrium,when Y/Zn ratio<0.14.

Microstructure,Mechanical Properties and Corrosion Behavior of Extruded Mg–Zn–Ag Alloys with Single-Phase Structure

Mg–Zn–Ag alloys have been extensively studied in recent years for potential biodegradable implants due to their unique mechanical properties,biodegradability and biocompatibility.In the present study,Mg–3Zn-x Ag（wt%,x=0.2,0.5 and0.8）alloys with single-phase crystal structure were prepared by backward extrusion at 340°C.The addition of Ag element into Mg–3Zn slightly influences the ultimate tensile strength and microstructure,but the elongation firstly increases from12%to 19.8%and then decreases from 19.8%to 9.9%with the increment of Ag concentration.The tensile yield strength,ultimate tensile strength and elongation of Mg–3Zn–0.2Ag alloy reach up to 142,234 MPa and 19.8%,respectively,which are the best mechanical performance of Mg–Zn–Ag alloys in the present work.The extruded Mg–3Zn–0.2Ag alloy also possesses the best corrosion behavior with the corresponding corrosion rate of 3.2 mm/year in immersion test,which could be explained by the single-phase and uniformly distributed grain structure,and the fewer twinning.

Phase equilibria of low-Ni side in Nb-Ni-Ti system at 1100℃

The phase equilibria related to liquid phase in low-Ni side of Nb-Ni-Ti system at 1100℃were investigated through scanning electron microscope(SEM),electron probe micro-analyzer(EPMA),X-ray diffraction(XRD)and differential scanning calorimetry(DSC).The results show that there exists liquid phase in equilibrium with continuous solid solution(Nb,βTi)and compound TiNi in low-Ni side of Nb-Ni-Ti system at 1100℃.The liquid phase region originates from low-Ni side of binary TiNi system and extends to 9.4 at%Nb in isothermal section of Nb-Ni-Ti phase diagram.The solid solubility of Nb in binary compound TiNi is about 10.6 at%.At 1100℃,there exist two three-phase regions consisting of liquid+(Nb,βTi)+TiNi and(Nb,βTi)+TiNi+X_B in Nb-Ni-Ti system,where X_B is the compound with hexagonal structure and composition of 32.8 Nb-44.5 Ni-22.7 Ti.The wide two-phase region(Nb,βTi)+TiNi exists between these two three-phase regions.In this two-phase region,Ti content in continuous solid solution(Nb,βTi)varies from6.6 at%to 25.7 at%,but Ni content is almost the same,which is about 4.0 at%.The eutectic transformation L■(Nb,βTi)+TiNi takes place at about 1138℃in Nb-Ni-Ti ternary system.