Microstructure and Texture Evolution during Superplastic Deformation of SP700 Titanium Alloy

The superplastic tensile test was carried out on SP700 (Ti-4.5Al-3V-2Mo-2Fe) titanium alloy sheet at 760 °C by the method of maximum m value, and the microstructure characteristics were investigated to understand the deformation mechanism. The results indicated that the examined alloy showed an extremely fine grain size of ~1.3 μm and an excellent superplasticity with fracture elongation of up to 3000%. The grain size and the volume fraction of the β phase increased as the strain increased, accompanied by the elements’ diffusion. The β-stabilizing elements (Mo, Fe, and V) were mainly dissolved within the β phase and diffused from α to β phase furthermore during deformation. The increase in strain leads to the accumulation of dislocations, which results in the increase in the proportion of low angle grain boundaries by 15%. As the deformation process, the crystal of α grains rotated, and the texture changed, accompanied by the accumulation of dislocations. The phase boundary (α/β) sliding accommodated by dislocation slip was the predominant mechanism for SP700 alloy during superplastic deformation.     

A High-Strain-Rate Superplasticity of the Al-Mg-Si-Zr-Sc Alloy with Ni Addition

The current study analyzed the effect of Ni content on the microstructure and superplastic deformation behavior of the Al-Mg-Si-Cu-based alloy doped with small additions of Sc and Zr. The superplasticity was observed in the studied alloys due to a bimodal particle size distribution. The coarse particles of eutectic origin Al₃Ni and Mg₂Si phases with a total volume fraction of 4.0–8.0% and a mean size of 1.4–1.6 µm provided the particles with a stimulated nucleation effect. The L1₂– structured nanoscale dispersoids of Sc- and Zr-bearing phase inhibited recrystallization and grain growth due to a strong Zener pinning effect. The positive effect of Ni on the superplasticity was revealed and confirmed by a high-temperature tensile test in a wide strain rate and temperature limits. In the alloy with 4 wt.% Ni, the elongation-to-failure of 350–520% was observed at 460 °C, in a strain rate range of 2 × 10⁻³–5 × 10⁻² s⁻¹.     

Investigation of Effect of Preliminary Annealing on Superplasticity of Ultrafine-Grained Conductor Aluminum Alloys Al-0.5%Mg-Sc

Effect of preliminary precipitation of Al₃Sc particles on the characteristics of superplastic conductor Al-0.5%Mg-X%Sc (X = 0.2, 0.3, 0.4, 0.5 wt.%) alloys with ultrafine-grained (UFG) microstructure has been studied. The precipitation of the Al₃Sc particles took place during long-time annealing of the alloys at 300 °C. The preliminary annealing was shown to affect the superplasticity characteristics of the UFG Al-0.5%Mg-X%Sc alloys (the elongation to failure, yield stress, dynamic grain growth rate) weakly but to promote more intensive pore formation and to reduce the volume fraction of the recrystallized microstructure in the deformed and non-deformed parts of the aluminum alloy specimens. The dynamic grain growth was shown to go in the deformed specimen material nonuniformly–the maximum volume fraction of the recrystallized microstructure was observed in the regions of the localization of plastic deformation.     

High Strain Rate Quasi-Superplasticity Behavior in an Ultralight Mg-9.55Li-2.92Al-0.027Y-0.026Mn Alloy Fabricated by Multidirectional Forging and Asymmetrical Rolling

To explore new approaches to severe plastic deformation and the ductility of a multicomponent magnesium–lithium alloy, an ultralight microduplex Mg-9.55Li-2.92Al-0.027Y-0.026Mn alloy was made by novel multidirectional forging and asymmetrical rolling, and the superplasticity behavior was investigated by optical microscope, hot tensile test, and modeling. The average grain size is 1.9 μm in this alloy after multidirectional forging and asymmetrical rolling. Remarkable grain refinement caused by such a forming, which turns the as-cast grain size of 144.68 μm into the as-rolled grain size of 1.9 μm, is achieved. The elongation to failure of 228.05% is obtained at 523 K and 1 × 10⁻² s⁻¹, which demonstrates the high strain rate quasi-superplasticity. The maximum elongation to failure of 287.12% was achieved in this alloy at 573 K and 5 × 10⁻⁴ s⁻¹. It was found that strain-induced grain coarsening at 523 K is much weaker than the strain-induced grain coarsening at 573 K. Thus, the ductility of 228.05% is suitable for application in high strain rate superplastic forming. The stress exponent of 3 and the average activation energy for deformation of 50.06 kJ/mol indicate that the rate-controlling deformation mechanism is dislocation-glide controlled by pipe diffusion.     

Superplastic Deformation of Alumina Composites Reinforced with Carbon Nanofibers and with Graphene Oxide Sintered by SPS—Experimental Testing and Theoretical Interpretation

The superplastic behavior of alumina-based nanostructured ceramics (Al₂O₃) is an important issue in the world of materials. The main body of this paper is an analysis of the creep behavior of polycrystals, with grain boundary sliding as the main deformation mechanism at high temperatures. Concomitant accommodation of grain shapes to preserve spatial continuity has a comparatively small effect on the strain rate. The constitutive equations for small deformations, relating strain and strain rate, derived from two models for grain sliding, are compared with the experimental data with their respective uncertainties. The data follow from experiments on the plastic deformation of alumina composites reinforced, on the one hand by graphene oxide, and on the other hand by carbon nanofibers sintered by SPS. The results show good agreement between experiment and theory for these advanced ceramics, particularly for one of the assumed models. The values obtained of ξ² for model A were in the interval 0.0002–0.1189, and for model B were in the interval 0.000001–0.0561. The values obtained of R² for model A were in the interval 0.9122–0.9994, and for model B were in the interval 0.9586–0.9999. The threshold stress was between (3.05 · 10⁻¹⁵–25.68) MPa.     

Influence of Machining Parameters on Cutting and Chip-Formation Process during Cortical Bone Orthogonal Machining

Cortical bone machining is commonly used in craniofacial surgery. The shaping of bone surfaces requires a precise determination of the process’s complexity due to the cutting tool’s defined or undefined geometry. Therefore, research was carried out to assess the impact of the rake angle (γ), clearance angle and depth of cut (d) on the cortical bone machining process. Analysis was carried out based on the orthogonal cutting in three directions. The cutting tool shape was simplified, and the cutting forces and the chip-formation process were monitored. The highest values of the resultant cutting force and shear force were recorded for γ < 0. The specific cutting force decreases with the increase of d. Cutting in the transverse direction is characterized by the highest values of resultant cutting force and shear force. The coefficient of friction depends primarily on the d and takes a constant value or increases with the increase of γ. The tests showed that the chips are formed in the entire range of d ≥ 0.5 µm and create regular shapes for d ≥ 10 µm. The research novelty confirms that even negative cutting angles guarantee controlled cutting and can find wider application in surgical procedures.     

Ductile-to-Brittle Transition and Brittle Fracture Stress of Ultrafine-Grained Low-Carbon Steel

Ductile-to-brittle transition (DBT) temperature and brittle fracture stress, σ_F, are important toughness criteria for structural materials. In this paper, low-carbon steels with an ultrafine elongated grain (UFEG) structure (transverse grain size 1.2 μm) and with two ferrite (α)-pearlite structure with grain sizes 10 µm and 18 µm were prepared. The UFEG steel was fabricated using multipass warm biaxial rolling. The tensile tests with a cylindrical specimen and three-point bending tests with a single-edge-notched specimen were performed at −196 °C. The local stress near the notch was quantitatively calculated via finite element analysis (FEA). The σ_F for each sample was quantified based on the experimental results and FEA. The relationship between σ_F and d_α in the wide range of 1.0 μm to 138 μm was plotted, including data from past literature. Finally, the conditions of grain size and temperature that cause DBT fracture in low-carbon steel were shown via the stress−d^−1/2 map. The results quantitatively showed the superiority of α grain size for brittle fracture.     

Revised microcalcification hypothesis for fibrous cap rupture in human coronary arteries

Using 2.1-µm high-resolution microcomputed tomography, we have examined the spatial distribution, clustering, and shape of nearly 35,000 microcalcifications (µCalcs) ≥ 5 µm in the fibrous caps of 22 nonruptured human atherosclerotic plaques. The vast majority of these µCalcs were <15 µm and invisible at the previously used 6.7-µm resolution. A greatly simplified 3D finite element analysis has made it possible to quickly analyze which of these thousands of minute inclusions are potentially dangerous. We show that the enhancement of the local tissue stress caused by particle clustering increases rapidly for gap between particle pairs (h)/particle diameter (D) < 0.4 if particles are oriented along the tensile axis of the cap. Of the thousands of µCalcs observed, there were 193 particle pairs with h/D ≤ 2 (tissue stress factor > 2), but only 3 of these pairs had h/D ≤ 0.4, where the local tissue stress could increase a factor > 5. Using nondecalcified histology, we also show that nearly all caps have µCalcs between 0.5 and 5 µm and that the µCalcs ≥ 5 µm observed in high-resolution microcomputed tomography are agglomerations of smaller calcified matrix vesicles. µCalcs < 5 µm are predicted to be not harmful, because the tiny voids associated with these very small particles will not explosively grow under tensile forces because of their large surface energy. These observations strongly support the hypothesis that nearly all fibrous caps have µCalcs, but only a small subset has the potential for rupture.     

Haemoxygenase modulates cytokine induced neutrophil chemoattractant in hepatic ischemia reperfusion injury

AIM To investigate the hepatic microcirculatory changes due to Haemoxygenase(HO),effect of HO inhibition on remote ischemic preconditioning(RIPC) and modulation of CINC.METHODS Eight groups of animals were studied- Sham,ischemia reperfusion injury(IRI) the animals were subjected to 45 min of hepatic ischemia followed by three hours of reperfusion,RIPC(remote ischemic preconditioning) + IRI group,remote ischemic preconditioning in sham(RIPC + Sham),PDTC + IR(Pyridodithiocarbamate,HO donor),Zn PP + RIPC + IRI(Zinc protoporphyrin prior to preconditioning),IR-24(45 min of ischemia followed by 24 h of reperfusion),RIPC+IR-24(preconditioning prior to. After 3 and 24 h of reperfusion the animals were killed by exsanguination and samples were taken. RESULTS Velocity of flow(160.83 ± 12.24 μm/s),sinusoidal flow(8.42 ± 1.19) and sinusoidal perfusion index(42.12 ± 7.28) in hepatic IR were lower(P 0.05) in comparison to RIPC and PDTC(HO inducer). RIPC increased velocity of flow(328.04 ± 19.13 μm/s),sinusoidal flow(17.75 ± 2.59) and the sinusoidal perfusion index(67.28 ± 1.82)(P 0.05). PDTC(HO induction) reproduced the effects of RIPC in hepatic IR. PDTC restored RBC velocity(300.88 ± 22.109 μm/s),sinusoidal flow(17.66 ± 3.71) and sinusoidal perfusion(82.33 ± 3.5) to near sham levels. Zn PP(HO inhibition) reduced velocity of flow of RBC in the RIPC group(170.74 ± 13.43 μm/s and sinusoidal flow in the RIPC group(9.46 ± 1.34). Zn PP in RIPC(60.29 ± 1.82) showed a fall in perfusion only at 180 min of reperfusion. Neutrophil adhesion in IR injury is seen in both postsinusoidal venules(769.05 ± 87.48) and sinusoids(97.4 ± 7.49). Neutrophil adhesion in RIPC + IR injury is reduced in both postsinusoidal venules(219.66 ± 93.79) and sinusoids(25.69 ± 9.08)(P 0.05). PDTC reduced neutrophil adhesion in both postsinusoidal venules(89.58 ± 58.32) and sinusoids(17.98 ± 11.01)(P 0.05) reproducing the effects of RIPC. Zn PP(HO inhibition) increased venular(589.04 ± 144.36) and sinusoidal neutrophil adhesion in preconditioned animals(121.39 ± 30.65)(P 0.05). IR after 24 h of reperfusion increased venular and sinusoidal neutrophil adhesion in comparison to the early phase and was significantly reduced by RIPC. Hepatocellular cell death in IRI(80.83 ± 13.03),RIPC + IR(17.35 ± 2.47),and PTDC+IR(11.66 ± 1.17) Zn PP + RIPC + IR(41.33 ± 3.07) reduced hepatocellular death. Zn PP significantly increased hepatocellular death(P 0.05 PTDC/RIPC vs Zn PP and IR). The CINC cytokine levels in sham(101.32 ± 6.42). RIPC + sham(412.18 ± 65.24) as compared to sham(P 0.05). Hepatic IR(644.08 ± 181.24)(P 0.05). RIPC CINC-1 levels in the early phase(401.62 ± 78.56). And PDTC(HO inducer) CINC-1 levels in hepatic IR(413.36 ± 63.06) were significantly lower. HO inhibition in preconditioned animals with Zinc protoporphyrin increased serum CINC levels(521.81 ± 74.9)(P 0.05). The serum CINC levels were high in the late phase of hepatic IR(15306 ± 1222.04). RIPC reduced CINC levels in the late phase of IR(467.46 ± 26.06),P 0.05.CONCLUSION RIPC protects hepatic microcirculation by induction of HO and modulation of CINC in hepatic IR.     

Effect of Sb and Zn Addition on the Microstructures and Tensile Properties of Sn–Bi-Based Alloys

The tensile behavior of Sn–Bi–Cu and Sn–Bi–Ni alloys has been widely investigated. Reportedly, the addition of small amounts of a third element can refine the microstructures of the eutectic Sn-58mass% Bi solder and improve its ductility. However, the superplasticity mechanism of Sn-based alloys has not been clearly established. Therefore, in this study, the effects of Sb and Zn addition on the microstructures and tensile properties of Sn–Bi-based alloys were investigated. The alloys were subjected to tensile tests under various strain rates and temperatures. We found that Zn- and Sb-added Sn–Bi-based alloys demonstrated superplastic deformation at high temperatures and low strain rates. Sb addition significantly affected the elongation of the Sn–Bi–Sb alloys because the metal dissolves in both the primary Sn phase and the eutectic Sn–Bi matrix. The segregation of Zn and formation of needle-like Zn particles at the eutectic Sn–Bi phase boundary affected the superplastic deformation of the alloys. The deformation of the Sn–40Bi-based alloys at high temperatures and low strain rates led to dynamic recovery, dynamic recrystallization, and/or grain boundary slip because of the accumulation of voids.     

Intestinal barrier dysfunction is involved in the development of systemic inflammatory responses and lung injury in type A aortic dissection: a case-control study

BackgroundThe definite pathogenesis of lung injury complicated by type A aortic dissection (TAAD) remains unclear. In this paper, we investigated the relationship between intestinal injury, lung injury, and systemic inflammatory responses, with the aim of exploring the mechanism underlying intestinal injury and its impact on systemic inflammatory responses and lung injury in patients with TAAD.MethodsPatients with TAAD (n=36) and those with aortic root aneurysm (ARA) (n=30) were compared. TAAD patients were younger and had higher creatinine (Cr) than ARA patients. White blood cell (WBC) count, neutrophil count, neutrophil percentage, interleukin (IL)-6, IL-8, tumor necrosis factor α (TNF-α), C-reactive protein (CRP), histamine (HIS) levels, PaO₂-FiO₂ ratio, diamine oxidase (DAO), intestinal fatty acid binding protein (iFABP), and peptidoglycan (PGN) were measured using the same laboratory methods between the two groups.ResultsIncreased WBC [(9.70±4.05)×10⁹/L vs. (5.88±1.2)×10⁹/L, P<0.001], neutrophil [(7.65±4.27)×10⁹/L vs. (3.40±0.97)×10⁹/L, P<0.001], neutrophil percentage [(74.73±13.42)% vs. (57.67±9.45)%, P<0.001], IL-6 (37.48±4.87 vs. 20.90±0.92 pg/mL, P<0.001), IL-8 (97.15±9.11 vs. 69.46±3.17 pg/mL, P<0.001), TNF-α (71.32±10.35 vs. 33.90±2.27 pg/mL, P<0.001), CRP (10.67±1.62 vs. 4.43±0.26 µg/mL, P<0.001), HIS (13.29±1.88 vs. 7.63±0.58 ng/mL, P<0.001), DAO (24.94±4.72 vs. 10.92±2.44 U/L, P<0.001), iFABP (879.01±190.12 vs. 206.35±42.20 pg/mL, P<0.001), and PGN (31.10±5.51 vs. 12.52±2.20 ng/mL, P<0.001) and decreased PaO₂-FiO₂ ratio (365.35±146.47 vs. 447.86±70.80 mmHg, P=0.01) were detected in TAAD group relative to ARA group. In TAAD group, positive correlations were detected between DAO and inflammatory cytokines [IL-6 (r=0.56, P<0.001), IL-8 (r=0.61, P<0.001), TNF-α (r=0.71, P<0.001), and CRP (r=0.68, P<0.001)], between iFABP and inflammatory cytokines [IL-6 (r=0.72, P<0.001), IL-8 (r=0.71, P<0.001), TNF-α (r=0.90, P<0.001), and CRP (r=0.89, P<0.001)], between DAO and PGN (r=0.52, P<0.001), between iFABP and PGN (r=0.74, P<0.001), between PGN and inflammatory cytokines [IL-6 (r=0.85, P<0.001), IL-8 (r=0.44, P<0.001), TNF-α (r=0.61, P<0.001), and CRP (r=0.73, P<0.001)]. In acute TAAD subgroup, PGN and PaO₂-FiO₂ ratio were negatively correlated (r=−0.50, P=0.036).ConclusionsSystemic inflammatory responses in TAAD patients may lead to lung and intestine injury, and the latter may be involved in the development of systemic inflammatory responses and lung injury in these patients.     

Surface Characteristics and Microbiological Analysis of a Vat-Photopolymerization Additive-Manufacturing Dental Resin

The wide application of additive manufacturing in dentistry implies the further investigation into oral micro-organism adhesion and biofilm formation on vat-photopolymerization (VP) dental resins. The surface characteristics and microbiological analysis of a VP dental resin, printed at resolutions of 50 μm (EG-50) and 100 μm (EG-100), were evaluated against an auto-polymerizing acrylic resin (CG). Samples were evaluated using a scanning electron microscope, a scanning white-light interferometer, and analyzed for Candida albicans (CA) and Streptococcus mutans (SM) biofilm, as well as antifungal and antimicrobial activity. EG-50 and EG-100 exhibited more irregular surfaces and statistically higher mean (Ra) and root-mean-square (rms) roughness (EG-50-Ra: 2.96 ± 0.32 µm; rms: 4.05 ± 0.43 µm/EG-100-Ra: 3.76 ± 0.58 µm; rms: 4.79 ± 0.74 µm) compared to the CG (Ra: 0.52 ± 0.36 µm; rms: 0.84 ± 0.54 µm) (p < 0.05). The biomass and extracellular matrix production by CA and SM and the metabolic activity of SM were significantly decreased in EG-50 and EG-100 compared to CG (p < 0.05). CA and SM growth was inhibited by the pure unpolymerized VP resin (48 h). EG-50 and EG-100 recorded a greater irregularity, higher surface roughness, and decreased CA and SM biofilm formation over the CG.     

Alterations in gut microbiota during remission and recurrence of diabetes after duodenal-jejunal bypass in rats

AIM: To observe the alterations in gut microbiota in high-fat diet(HFD)-induced diabetes recurrence after duodenal-jejunal bypass(DJB) in rats. METHODS: We assigned HDF- and low-dose streptozotocin-induced diabetic rats into two major groups to receive DJB and sham operation respectively. When the DJB was completed, we used HFD to induce diabetes recurrence. Then, we grouped the DJB-operated rats by blood glucose level into the DJB-remission(DJB-RM) group and the DJB-recurrence(DJB-RC) group. At a sequence of time points after operations, we compared calorie content in the food intake(calorie intake), oral glucose tolerance test, homeostasis model assessment of insulin resistance(HOMA-IR), concentrations of glucagon-like peptide 1(GLP-1), serum insulin, total bile acids(TBAs) and lipopolysaccharide(LPS) and alterations in colonic microbiota.RESULTS: The relative abundance of Firmicutes in the control(58.06% ± 11.12%; P 0.05 vs sham; P 0.05 vs DJB-RC) and DJB-RM(55.58% ± 6.16%; P 0.05 vs sham; P 0.05 vs DJB-RC) groups was higher than that in the sham(29.04% ± 1.36%) and DJB-RC(27.44% ± 2.17%) groups; but the relative abundance of Bacteroidetes was lower(control group: 33.46% ± 10.52%, P 0.05 vs sham 46.88% ± 2.34%, P 0.05 vs DJB-RC 47.41% ± 5.67%. DJB-RM group: 34.63% ± 3.37%, P 0.05 vs sham; P 0.05 vs DJB-RC). Escherichia coli was higher in the sham(15.72% ± 1.67%, P 0.05 vs control, P 0.05 vs DJB-RM) and DJB-RC(16.42% ± 3.00%; P 0.05 vs control; P 0.05 vs DJB-RM) groups than in the control(3.58% ± 3.67%) and DJB-RM(4.15% ± 2.76%) groups. Improved HOMA-IR(2.82 ± 0.73, P 0.05 vs DJB-RC 4.23 ± 0.72), increased TBAs(27803.17 ± 4673.42 ng/m L; P 0.05 vs DJB-RC 18744.00 ± 3047.26 ng/m L) and decreased LPS(0.12 ± 0.04 ng/m L, P 0.05 vs DJBRC 0.19 ± 0.03 ng/m L) were observed the in DJB-RM group; however, these improvements were reversed in the DJB-RC group, with the exception of GLP-1(DJB-RM vs DJB-RC P 0.05). CONCLUSION: Alterations in gut microbiota may be responsible for the diabetes remission and recurrence after DJB, possibly by influencing serum LPS and TBAs.     

1H nuclear magnetic resonance spectroscopy-based metabonomic study in patients with cirrhosis and hepatic encephalopathy

AIM: To identify plasma metabolites used as biomarkers in order to distinguish cirrhotics from controls and encephalopathics.METHODS: A clinical study involving stable cirrhotic patients with and without overt hepatic encephalopathy was designed. A control group of healthy volunteers was used. Plasma from those patients was analysed using ¹H - nuclear magnetic resonance spectroscopy. We used the Carr Purcell Meiboom Gill sequence to process the sample spectra at ambient probe temperature. We used a gated secondary irradiation field for water signal suppression. Samples were calibrated and referenced using the sodium trimethyl silyl propionate peak at 0.00 ppm. For each sample 128 transients (FID’s) were acquired into 32 K complex data points over a spectral width of 6 KHz. 30 degree pulses were applied with an acquisition time of 4.0 s in order to achieve better resolution, followed by a recovery delay of 12 s, to allow for complete relaxation and recovery of the magnetisation. A metabolic profile was created for stable cirrhotic patients without signs of overt hepatic encephalopathy and encephalopathic patients as well as healthy controls. Stepwise discriminant analysis was then used and discriminant factors were created to differentiate between the three groups.RESULTS: Eighteen stabled cirrhotic patients, eighteen patients with overt hepatic encephalopathy and seventeen healthy volunteers were recruited. Patients with cirrhosis had significantly impaired ketone body metabolism, urea synthesis and gluconeogenesis. This was demonstrated by higher concentrations of acetoacetate (0.23 ± 0.02 vs 0.05 ± 0.00, P < 0.01), and b-hydroxybutarate (0.58 ± 0.14 vs 0.08 ± 0.00, P < 0.01), lower concentrations of glutamine (0.44 ± 0.08 vs 0.63 ± 0.03, P < 0.05), histidine (0.16 ± 0.01 vs 0.36 ± 0.04, P < 0.01) and arginine (0.08 ± 0.01 vs 0.14 ± 0.02, P < 0.03) and higher concentrations of glutamate (1.36 ± 0.25 vs 0.58 ± 0.04, P < 0.01), lactate (1.53 ± 0.11 vs 0.42 ± 0.05, P < 0.01), pyruvate (0.11 ± 0.02 vs 0.03 ± 0.00, P < 0.01) threonine (0.39 ± 0.02 vs 0.08 ± 0.01, P < 0.01) and aspartate (0.37 ± 0.03 vs 0.03 ± 0.01). A five metabolite signature by stepwise discriminant analysis could separate between controls and cirrhotic patients with an accuracy of 98%. In patients with encephalopathy we observed further derangement of ketone body metabolism, impaired production of glycerol and myoinositol, reversal of Fischer’s ratio and impaired glutamine production as demonstrated by lower b-hydroxybutyrate (0.58 ± 0.14 vs 0.16 ± 0.02, P < 0.0002), higher acetoacetate (0.23 ± 0.02 vs 0.41 ± 0.16, P < 0.05), leucine (0.33 ± 0.02 vs 0.49 ± 0.05, P < 0.005) and isoleucine (0.12 ± 0.02 vs 0.27 ± 0.02, P < 0.0004) and lower glutamine (0.44 ± 0.08 vs 0.36 ± 0.04, P < 0.013), glycerol (0.53 ± 0.03 vs 0.19 ± 0.02, P < 0.000) and myoinositol (0.36 ± 0.04 vs 0.18 ± 0.02, P < 0.010) concentrations. A four metabolite signature by stepwise discriminant analysis could separate between encephalopathic and cirrhotic patients with an accuracy of 87%.CONCLUSION: Patients with cirrhosis and patients with hepatic encephalopathy exhibit distinct metabolic abnormalities and the use of metabonomics can select biomarkers for these diseases.     

Liver reserve function assessment by acoustic radiation force impulse imaging

AIM: To evaluate the utility of liver reserve function by acoustic radiation force impulse (ARFI) imaging in patients with liver tumors.METHODS: Seventy-six patients with liver tumors were enrolled in this study. Serum biochemical indexes, such as aminotransferase (ALT), aspartate aminotransferase (AST), serum albumin (ALB), total bilirubin (T-Bil), and other indicators were observed. Liver stiffness (LS) was measured by ARFI imaging, measurements were repeated 10 times, and the average value of the results was taken as the final LS value. Indocyanine green (ICG) retention was performed, and ICG-K and ICG-R15 were recorded. Child-Pugh (CP) scores were carried out based on patient’s preoperative biochemical tests and physical condition. Correlations among CP scores, ICG-R15, ICG-K and LS values were observed and analyzed using either the Pearson correlation coefficient or the Spearman rank correlation coefficient. Kruskal-Wallis test was used to compare LS values of CP scores, and the receiver-operator characteristic (ROC) curve was used to analyze liver reserve function assessment accuracy.RESULTS: LS in the ICG-R15 10%-20% group was significantly higher than in the ICG-R15 < 10% group; and the difference was statistically significant (2.19 ± 0.27 vs 1.59 ± 0.32, P < 0.01). LS in the ICG-R15 > 20% group was significantly higher than in the ICG-R15 < 10% group; and the difference was statistically significant (2.92 ± 0.29 vs 1.59 ± 0.32, P < 0.01). The LS value in patients with CP class A was lower than in patients with CP class B (1.57 ± 0.34 vs 1.86 ± 0.27, P < 0.05), while the LS value in patients with CP class B was lower than in patients with CP class C (1.86 ± 0.27 vs 2.47 ± 0.33, P < 0.01). LS was positively correlated with ICG-R15 (r = 0.617, P < 0.01) and CP score (r = 0.772, P < 0.01). Meanwhile, LS was negatively correlated with ICG-K (r = -0.673, P < 0.01). AST, ALT and T-Bil were positively correlated with LS, while ALB was negatively correlated with LS (P < 0.05). The ROC curve revealed that the when the LS value was 2.34 m/s, the Youden index was at its highest point, sensitivity was 69.2% and specificity was 92.1%.CONCLUSION: For patients with liver tumors, ARFI imaging is a useful tool for assessing liver reserve function.     

Effect of Delamination and Grain Refinement on Fracture Energy of Ultrafine-Grained Steel Determined Using an Instrumented Charpy Impact Test

Improving the balance of strength and toughness in structural materials is an ongoing challenge. Delamination and grain refinement are some of the methods used to do this. In this paper, two different steels, 0.15% C–0.3% Si–1.5% Mn–Fe and 0.4% C–2% Si–1% Cr–1% Mo–Fe (mass %), were prepared. Two steel bars with an ultrafine elongated grain (UFEG) structure were fabricated via multipass warm caliber rolling. The UFEG steels were characterized by a strong <110>//rolling-direction fiber texture. The transverse grain size, d_t, was 1.0 µm for the low-carbon steel and 0.26 µm for the medium-carbon steel. For comparison, conventional heat-treated steels were also fabricated. An instrumented Charpy impact test was performed, and the impact load (P) and deflection (u) during the test were recorded. The P–u relations at the test temperature at which delamination fracture occurred exhibited a unique curve. Delamination effectively enhances the low-temperature toughness, and this was characterized by a plateau region of constant load in the P–u curve. Assuming no delamination, two routes in the P–u curves, the ductile route and the brittle route, were proposed. The results showed that the proposed methods can be predicted by an energy curve for ultrafine grained steels. Delamination is a more effective method of enhancing toughness for ultra-high-strength steels.     

Impacts of common factors of life style on serum liver enzymes

AIM: To investigate the impacts of gender, age and factors of life style (alcohol, overweight, coffee and smoking) on serum liver enzymes.METHODS: Serum alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) were measured from 6269 apparently healthy individuals (2851 men, 3418 women, mean age 45 ± 12 years, range 25-74 years) in a national cross-sectional health survey. All subjects underwent detailed clinical examinations and interviews including the amount and pattern of alcohol use, coffee consumption and smoking habits.RESULTS: In this population with a mean ± SD alcohol consumption of 65 ± 105 g/wk and body mass index (BMI) of 26.1 ± 4.3 kg/m², both ALT and GGT were significantly influenced by alcohol use (P < 0.001) and BMI (P < 0.001), whereas smoking increased only GGT (P < 0.001). A significant effect of age on ALT was seen in men (P < 0.001) whereas not in women. Significant two-factor interactions of alcohol use in men were observed with age (ALT: P < 0.01; GGT: P < 0.001) and BMI (GGT: P < 0.05). For ALT, a significant interaction also occurred between BMI and age (P < 0.005). In contrast, women showed significant interactions of alcohol use with BMI (GGT: P < 0.05), smoking (GGT: P < 0.001), and coffee consumption (GGT: P < 0.001).CONCLUSION: Life-style associated changes in liver enzymes may reflect health risks, which should be considered in the definition of normal limits for liver enzymes.     

Survey of Grain Boundary Energies in Tungsten and Beta-Titanium at High Temperature

Heat treatment is a necessary means to obtain desired properties for most of the materials. Thus, the grain boundary (GB) phenomena observed in experiments actually reflect the GB behaviors at relatively high temperature to some extent. In this work, 405 different GBs were systematically constructed for body-centered cubic (BCC) metals and the grain boundary energies (GBEs) of these GBs were calculated with molecular dynamics for W at 2400 K and β-Ti at 1300 K and by means of molecular statics for Mo and W at 0 K. It was found that high temperature may result in the GB complexion transitions for some GBs, such as the Σ11{332}{332} of W. Moreover, the relationships between GBEs and sin(θ) can be described by the functions of the same type for different GB sets having the same misorientation axis, where θ is the angle between the misorientation axis and the GB plane. Generally, the GBs tend to have lower GBE when sin(θ) is equal to 0. However, the GB sets with the <110> misorientation axis have the lowest GBE when sin(θ) is close to 1. Another discovery is that the local hexagonal-close packed α phase is more likely to form at the GBs with the lattice misorientations of 38.9°/<110>, 50.5°/<110>, 59.0°/<110> and 60.0°/<111> for β-Ti at 1300 K.     

Incidence and Outcomes of Acute Respiratory Distress Syndrome: A Nationwide Registry-Based Study in Taiwan, 1997 to 2011

Most epidemiological studies of acute respiratory distress syndrome (ARDS) have been conducted in western countries, and studies in Asia are limited. The aim of our study was to evaluate the incidence, in-hospital mortality, and 1-year mortality of ARDS in Taiwan.We conducted a nationwide inpatient cohort study based on the Taiwan National Health Insurance Research Database between 1997 and 2011. A total of 40,876 ARDS patients (68% male; mean age 66 years) were identified by International Classification of Diseases, 9th edition coding and further analyzed for clinical characteristics, medical costs, and mortality.The overall crude incidence of ARDS was 15.74 per 100,000 person-years, and increased from 2.53 to 19.26 per 100,000 person-years during the study period. The age-adjusted incidence of ARDS was 15.19 per 100,000 person-years. The overall in-hospital mortality was 57.8%. In-hospital mortality decreased from 59.7% in 1997 to 47.5% in 2011 (P < 0.001). The in-hospital mortality rate was lowest (33.5%) in the youngest patients (age 18–29 years) and highest (68.2%) in the oldest patients (>80 years, P < 0.001). The overall 1-year mortality rate was 72.1%, and decreased from 75.8% to 54.7% during the study period. Patients who died during hospitalization were older (69 ± 17 versus 62 ± 19, P < 0.001) and predominantly male (69.8% versus 65.3%, P < 0.001). In addition, patients who died during hospitalization had significantly higher medical costs (6421 versus 5825 US Dollars, P < 0.001) and shorter lengths of stay (13 versus 19 days, P < 0.001) than patients who survived.We provide the first large-scale epidemiological analysis of ARDS incidence and outcomes in Asia. Although the overall incidence was lower than has been reported in a prospective US study, this may reflect underdiagnosis by International Classification of Diseases, 9th edition code and identification of only patients with more severe ARDS in this analysis. Overall, there has been a decreasing trend in in-hospital and 1-year mortality rates in recent years, likely because of the implementation of lung-protective ventilation.     

External Cardioversion of Atrial Fibrillation Causes an Early Improvement of Cardiac Performance: A Longitudinal Strain Analysis Study

Introduction:

Atrial fibrillation (AF) is often associated with heart failure. Several studies have demonstrated that resumption of sinus rhythm (SR) improves cardiac output in the long-term. Aims of this study were to evaluate the acute variations of left ventricular (LV) performance, following successful external cardioversion (ECV) of persistent AF using longitudinal strain (LSt) analysis, and the influence of inflammation.

Materials and Methods:

We enrolled 48 patients with AF (age: 73 ± 12 years, men: 83.3%). A standard transthoracic echocardiographic evaluation was performed before the procedure and 6 h later; this included the analysis of LV endocardial peak LSt, a measure of myocardial deformation. In the last 32 patients, plasma concentration of interleukin-6 (IL-6) was also determined.

Results:

Restoration of SR led to the decrease of heart rate (HR) (74 ± 21 vs 64 ± 10 bpm, P < 0.001) and LV end-systolic volume (30 ± 16 vs 27 ± 17 mL/m², P = 0.001), and to the increase of LV end-diastolic volume (LVEDV) (56 ± 20 vs 60 ± 21 mL/m², P = 0.036) and ejection fraction (EF) (48 ± 10 vs 57 ± 11%, P < 0.001). Peak LSt improved in 43 (89.6%) patients (-12.9 ± 3.3 vs -18.0 ± 4.7%, P < 0.001). Multivariate analysis (R = 0.729, P < 0.001) showed that strain changes were directly correlated with basal HR and the appearance of atrial mechanical activity and inversely correlated with corrected thyroid dysfunction, LVEDV and the presence of a permanent pacemaker. Higher levels of IL-6 negatively affected LV performance improvement.

Conclusions:

Effective ECV of AF determines a significant and fast improvement of LV performance, which is readily captured by LSt analysis. Inflammatory status may impact the response to SR restoration.