Search

Wear resistant composite layers were fabricated on 38CrMoAl steel by laser processing with NiCr/Cr3C2-CeO2 powders with addition of MoS or WS . The composite layers were heat treated at 150 and 300°C (MoS2), and 300 and 600°C (WS2). Microstructure, phases, microhardness, wear behaviour at room temperature and crack behaviour under loading of the laser processed and heat treated layers were investigated. Results indicate that undissolved MoS2 or WS2 were observed in all the layers. Heat treatment changed the microstructure and phases of all the laser processed layers. When the original majority phase of the laser processed layer was martensite, volume fraction of retained austenite increased after heat treatment; while when the original majority phase was austenite, volume fraction of retained austenite decreased after heat treatment. Full width at half maximum (FWHM) of martensite peaks in the laser processed layer with addition of 20 wt.% MoS2 decreased with heat treatment temperatures, indicating reduced defects in the heat treated layers. Laser processed layers with addition of 10 wt.% MoS2, 10 wt.% or 20 wt.% WS2 without heat treatment showed the best wear resistance while that with addition of 20 wt.% MoS2 showed the best wear resistance after heat treatment at 300°C. The wear mechanism of all the layers is abrasive, adhesive and oxidative wear, accompanied by the formation and removal of oxide film and sulphide containing tribofilms. The oxide film and sulphide lubricating phases formed on the worn surface during sliding wear play an important role in reducing friction and wear loss. Un-dissolved MoS2/WS2 and crack behaviour in case of loading is closely related to the microstructure of the pressed matrix. [ABSTRACT FROM AUTHOR]

Laser shock peening (LSP) is a competitive innovative surface treatment technique, which can induce compressive residual stresses in metal materials. In this investigation, a modified explicit finite element analysis (FEA) method was used to predict the residual stress distribution in 2050-T8 aluminum alloy induced by LSP. The laser shock sequence was programmed by VDLOAD ABAQUS subroutine. Simulated residual stresses from FEA showed good consistency with open literatures. Based on the method, the effects of LSP parameters such as overlapping percentage, number of impacts, laser power density, laser spot size on the average surface residual stress and average in-depth residual stress of 2050-T8 aluminum alloy were analyzed. [ABSTRACT FROM AUTHOR]

Summary: This paper provides the length–weight relationships for six fish species collected from the Anning River, one of the biggest tributaries of the Yalong River in China. A total of 1096 specimens belonging to six fish species were analyzed. Among them, the length–weight relationships for 4 fish species are first‐time reports for FishBase and new maximum lengths of one fish species is also reported. [ABSTRACT FROM AUTHOR]

Wear resistant composite layers were fabricated on 38CrMoAl steel by laser processing with NiCr/Cr3C2-CeO2 powders with addition of MoS or WS . The composite layers were heat treated at 150 and 300°C (MoS2), and 300 and 600°C (WS2). Microstructure, phases, microhardness, wear behaviour at room temperature and crack behaviour under loading of the laser processed and heat treated layers were investigated. Results indicate that undissolved MoS2 or WS2 were observed in all the layers. Heat treatment changed the microstructure and phases of all the laser processed layers. When the original majority phase of the laser processed layer was martensite, volume fraction of retained austenite increased after heat treatment; while when the original majority phase was austenite, volume fraction of retained austenite decreased after heat treatment. Full width at half maximum (FWHM) of martensite peaks in the laser processed layer with addition of 20 wt.% MoS2 decreased with heat treatment temperatures, indicating reduced defects in the heat treated layers. Laser processed layers with addition of 10 wt.% MoS2, 10 wt.% or 20 wt.% WS2 without heat treatment showed the best wear resistance while that with addition of 20 wt.% MoS2 showed the best wear resistance after heat treatment at 300°C. The wear mechanism of all the layers is abrasive, adhesive and oxidative wear, accompanied by the formation and removal of oxide film and sulphide containing tribofilms. The oxide film and sulphide lubricating phases formed on the worn surface during sliding wear play an important role in reducing friction and wear loss. Un-dissolved MoS2/WS2 and crack behaviour in case of loading is closely related to the microstructure of the pressed matrix. [ABSTRACT FROM AUTHOR]

Peritoneal ultrafiltration failure is a common reason for peritoneal dialysis (PD) withdrawal as well as mortality in PD patients. Based on the three-pore system, inter-cellular small pores and trans-cellular ultra-small pores (aquaporin-1) are mainly responsible for water transfer across the peritoneum. Both small and ultra-small pores-dependent water (free water) transport decline accompanied with time on PD, with more significant decrease in free water, resulting in peritoneal ultrafiltration failure. The reduction of free water transport is associated with fast peritoneal solute transfer, reduced crystalloid osmotic gradient due to increased interstitial glucose absorption, and declined osmotic conductance to glucose resulted from impaired aquaporin-1 function and peritoneal interstitial fibrosis. The decline of small pore-based water is mainly because of fast loss of crystalloid osmotic gradient, decrease of hydrostatic pressure mediated by peritoneal vasculopathy, as well as reduced absolute number of small pores. The current review discusses the advance on pathogenesis of acquired peritoneal ultrafiltration failure in long-term PD.

Objective: To compare the safety profile, angiographic and clinical outcomes between drug-coated balloon(DCB) only strategy versus drug eluting stent(DES) implantation in primary percutaneous coronary intervention(PCI) for acute myocardial infarction(AMI) patients. Methods: A total of 380 AMI patients who underwent primary PCI in Beijing Chaoyang Hospital from January 2016 to May 2019 were enrolled. They were allocated into DEB group( n= 180) or DES group( n= 200). The Primary endpoint was the major adverse cardiac events(MACE) in hospital and within 3 months after discharge, the composite event of cardiac death, non-fatal myocardial infarction(MI), target vessel revascularization(TVR) and in stent thrombosis. The secondary endpoints included: (1)TIMI blood flow grade and myocardial perfusion grade (TMP grade) of infarct-related vessels before and after PCI. (2)The degree of ST segment resolution(STR) between half hour and two hours after PCI, and STR was represented by percentage of summed ST-segment reduction between baseline and post-PCI. Using the most significant lead of ST segment elevation, calculating the rate of decline in the ST segment after treatment; or the most significant lead of the ST segment depression, to calculate the rate of recovery in the ST segment after treatment. STR<50% was defined as incomplete STR. (3)The occurrence of coronary artery dissection during operation. (4)The peak value of myocardial enzymes. (5)The incidence of bleeding in hospital and within 3 months after discharge. The inverse probability weighting method based on propensity score (IPTW) was used to compare the effects of the two treatments on MACE occurrence in the logistic regression model. Results: There was no significant difference in sex, age, risk factors of coronary heart disease, type and site of AMI, interventional therapy data( P> 0.05) between the two groups. The ratio of bifurcation lesions in DCB group was significantly higher than that in DES group, and the diameter of the DCB was smaller while the length was longer than that of DES (all P< 0.05). One death occurred in each group during hospitalization. Compared with the DES group, the incidence of MI ［2.8%(5/180) vs. 0.5% (1/200), P= 0.10］ and TVR ［2.8%(5/180) vs. 0.5%(1/200), P= 0.10］ in the DCB group during hospitalization showed an increasing trend, and were mostly associated with delayed coronary dissection. The incidence of MACE was similar between the two groups (3.3%(6/180) and 1.0%(2/200), P= 0.15) during hospitalization. There was no MACE occurred in the two groups within 3 months after discharge. There was no significant difference between the two groups in TIMI grade, TMP grade, incomplete STR rate and peak value of myocardial enzyme (all P> 0.05). The incidence of coronary artery dissection was significantly higher in DCB group than in DES group (8.3%(15/180) and 3.0%(6/200), P= 0.02), but most of them were type B or A dissection and did not need special treatment. There was no significant difference in bleeding event between the two groups( P= 0.91). Logistic regression analysis showed that there was no difference in the risk of MACE during hospitalization between DES and DCB groups for AMI patients receiving PCI (compared with DCB, OR= 0.35, 95 %CI 0.08-1.43, P= 0.13). Conclusions: The initial safety and efficacy profiles of DCB are similar with those of DES for the AMI patients during PCI. The study highlights that the incidence of coronary dissection (type A or B) is higher post DCB treatment than post DES, but it does not affect blood flow. However, the incidence of in-hospital MI due to delayed coronary dissection trends to be higher post DCB. So we should pay close attention to the risk of delayed coronary dissection after DCB in AMI patients with de novo lesion.

Objective: To evaluate the safety and feasibility of treating de novo coronary lesions with paclitaxel-eluting balloon. Methods: This is a retrospective study, which enrolled 76 patients with 80 de novo coronary lesions treated with paclitaxel-eluting balloons(<30% residual stenosis and there was no blood flow limited dissection after pretreatment) from April 2015 to November 2016 in Guangdong general hospital. The data of basic characteristics,procedures,devices and follow-up information were retrieved and analyzed. The primary endpoint was the composite of cardiac death, recurrent myocardial infarction and target lesion revascularization. Results: (1)The age was (63.3±10.3) years. There were 68.4%(52/76) acute coronary syndrome patients, prevalence of type 2 diabetes was 36.8%(28/76), and 64.5%(49/76)patients with at least one high bleeding risk. (2)The lesion length was (17.4±7.6)mm, and the stenosis was (88.1±8.2)%.The reference vessel diameter≥2.75 mm accounted for 51.2% (41/80), and bifurcation stenosis accounted for 67.5%(54/80). (3)53.7%(43/80) lesions were pretreated with scoring balloon to optimize plaque modification. The paclitaxel-eluting balloon length and diameter were (22.3±5.5)mm and (2.74±0.52)mm.The residual stenosis was (12.3±10.3)%. Procedural success was 88.8%(71/80).Bail-out stenting rate was 5.0%(4/80). (4)The median follow-up duration was 12(6, 25) months. Primary endpoint occurred in 3 cases (3.9%), including 2 cardiac deaths(1 patient died of recurrent myocardial infarction, and 1 patient died of acute heart failure induced by severe mitral insufficiency), and one patient receivedtarget lesion revascularization. Conclusion: In case of no more than 30% residual stenosis and no blood flow limited dissection after lesion pretreatment,it is safe and feasible to treat de novo coronary lesionsusing paclitaxel-eluting balloon.

Objective: Previous studies have shown that Transforming growth factor-β (TGF-β)/TGFβRII-Smad3 signaling is involved in articular cartilage homeostasis. However, the role of TGF-β/ALK5 signaling in articular cartilage homeostasis has not been fully defined. In this study, a combination of in vitro and in vivo approaches was used to elucidate the role of ALK5 signaling in articular cartilage homeostasis and the development of osteoarthritis (OA)., Design: Mice with inducible cartilage-specific deletion of Alk5 were generated to assess the role of ALK5 in OA development. Alterations in cartilage structure were evaluated histologically. The expressions of genes associated with articular cartilage homeostasis and TGF-β signaling were analyzed by qRT-PCR, western blotting and immunohistochemistry. The chondrocyte apoptosis was detected by TUNEL staining and immunohistochemistry. In addition, the molecular mechanism underlying the effects of TGF-β/ALK5 signaling on articular cartilage homeostasis was explored by analyzing the TGF-β/ALK5 signaling-induced expression of proteoglycan 4 (PRG4) using specific inhibitors., Results: Postnatal cartilage-specific deletion of Alk5 induced an OA-like phenotype with degradation of articular cartilage, synovial hyperplasia, osteophyte formation, subchondral sclerosis, as well as enhanced chondrocyte apoptosis, overproduction of catabolic factors, and decreased expressions of anabolic factors in chondrocytes. In addition, the expressions of PRG4 mRNA and protein were decreased in Alk5 conditional knockout mice. Furthermore, our results showed, for the first time, that TGF-β/ALK5 signaling regulated PRG4 expression partially through the protein kinase A (PKA)-CREB signaling pathway., Conclusions: TGF-β/ALK5 signaling maintains articular cartilage homeostasis, in part, by upregulating PRG4 expression through the PKA-CREB signaling pathway in articular chondrocytes., (Copyright © 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Objectives: To explore the species, quantity and distribution of diatoms in Ningbo three-river watershed during summer and to provide scientific basis for forensic examination of drowning cases in the waters of Ningbo., Methods: Water samples were collected in July and August of 2015. Fourteen water sampling points were selected from the Yao River, the Fenghua River and the Yong River. The morphological features of diatom species and dominant diatoms were distinguished by microscope., Results: A total of 16 species of diatoms were detected in the Yao River, the Fenghua River and the Yong River. Melosira was the dominant species in the Yao River, and the quantity and richness were higher than in other rivers. The richness of Cyclotella in the Yong River was higher than in other rivers. The richness of Pinnularia and Licmophora were higher in the Fenghua River than in the Yao River and the Yong River., Conclusions: The species and proportion of diatom is different in each river. Database of the species and relative composition for the diatoms in corresponding river is established, which may provide data support for forensic examination of drowning cases in Ningbo three-river watershed., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Forensic Medicine)

Objective: To study the efficacy and safety of tirofiban on acute ST segment elevation myocardial infarction (STEMI) in patients who do not receive early reperfusion therapy., Methods: A total of 153 STEMI patients without early reperfusion therapy were randomly distributed into tirofiban group (therapeutic group, n=78) and non-tirofiban group (control group, n=75). Coronary angiography was performed on the 5(th) and 10(th) day after treatment, and percutaneous coronary intervention (PCI) was conducted when necessary. The differences of initial patency of the infarct related artery (IRA), bleeding complication and clinic events within 30 days between these two groups were compared., Results: Tirofiban did not increase the percentage of patients with initial patency of IRA (60.3% vs 64.0%, P=0.63). The percentage of patients with thrombolysis in myocardial infarction (TIMI) 3 after PCI was 100.0% in tirofiban group and 97.1% in the control group (P=0.09). However, application of tirofiban significantly decreased poor myocardial perfusion rate after PCI (1.4% vs 8.8%, P=0.04). No significant differences were observed in major adverse cardiovascular events (MACE) (3.8% vs 2.7%, P=0.68) between therapeutic and control group. The same is true for mild (5/78 vs 4/75 cases, P=0.78) and severe hemorrhage (2/78 vs 1/75 cases, P=0.58), and severe thrombocytopenia (2/78 vs 0/75 cases, P=0.10) between these two groups within 30 days., Conclusions: Tirofiban did not increase initial patency in STEMI patients without early reperfusion therapy. However, it can improve myocardial perfusion after PCI.

Background and Aims: Hyperphosphatemia is an independent predictor for cardiovascular and all-cause mortality in patients undergoing peritoneal dialysis (PD). The study aimed to investigate the effect of dietary intervention on reducing serum phosphate concentration in hyperphosphatemic PD patients., Methods and Results: In this single-center clinical trial, 97 prevalent PD patients with serum phosphate concentration ≥ 1.6 mmol/l were allocated to the intervention (n = 48) or control (n = 49) group and followed up for 1 year. In addition to phosphate binder (calcium carbonate) therapy, patients in the intervention group were intensively educated to reduce phosphate-rich food intake and improve cooking methods. While stable in the control group (1.97 ± 0.20 to 1.94 ± 0.35 mmol/l, p > 0.05), the serum phosphate concentration decreased significantly in the intervention group (1.98 ± 0.28 to 1.65 ± 0.33 mmol/l, p = 0.015) concurrently with the drop in dietary phosphate intake (13.03 ± 3.39 to 10.82 ± 3.00 mg/kg ideal body weight/day, p = 0.001). Moreover, after 6 months of intervention, fewer patients needed to use calcium carbonate (from 64.6% to 41.5%, p = 0.029) and the medicine dose reduced significantly (from 2.25 (0, 3.94) to 0 (0, 1.50) g/day, p < 0.001)., Conclusions: Our data indicated that intensive dietary intervention of reducing phosphate-rich food intake and improving cooking methods attenuated hyperphosphatemia in PD patients. It suggests that regular assessment of dietary phosphate intake and modification of diet recipe and cooking methods are essential for hyperphosphatemia treatment in PD patients in addition to phosphate binder therapy., (Copyright © 2015 Elsevier B.V. All rights reserved.)