Microstructural Stability and Creep Performance of a Novel Low-Cost Single Crystal Superalloy

Z. H. Tan,X. G. Wang,Y. L. Du,Y. M. Li,Y. H. Yang,J. L. Liu,J. D. Liu,J. G. Li,Y. Z. Zhou,X. F. Sun 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The increasing pursuit of advanced aero-engines with lower ratio between the cost and performance has greatly promotedthe demanding of single crystal superalloys characterized by low cost and outstanding temperature capability. In this study,a novel low-cost single crystal superalloy was designed and the creep tests as well as micro-characterization were carried outon the experimental alloy. The results illustrated that the novel single crystal alloy exhibited an ideal microstructural stabilitywithout precipitating TCP phases, after long-term thermal exposure at the ultimate service temperature of third generationsingle crystal superalloys. Moreover, the experimental alloy with only 3 wt% Re addition demonstrated remarkable creepresistance and maintained a very low minimum creep rate at 1100 °C/137 MPa and 1120 °C/137 MPa, while the accumulationand coalescence of micro-pores had eventually led to the alloy fracture. Apart from that, the compact interfacial dislocationnetworks the 2nd γ′ phase were observed after high-temperature creep rupture, and the typical a < 010 > superdislocationswith relatively poor mobility was found at 1120 °C. At 760 °C/800 MPa, both the minimum creep velocity and entire creepstain was increased evidently, however, the ultimate creep rupture life of the alloy had still reached 200 h. The correspondingdeformation mechanism was identified as the combination of superdislocation pairs shearing and a/3 < 121 > partial dislocationcutting the γ′ phase with a SISF being generated. In general, the novel single crystal alloy characterized by remarkablemechanical properties and cost reduction possesses a great potential for future application in the advanced aircraft engines.

Efficacy of perineural versus intravenous dexamethasone in prolonging the duration of analgesia when administered with peripheral nerve blocks: a systematic review and meta-analysis

Tan Elizabeth Sein Jieh,Tan Yan Ru,Liu Christopher Wei Yang 대한마취통증의학회 2022 Korean Journal of Anesthesiology Vol.75 No.3

Background: Perineural dexamethasone has been regarded as a promising adjunct for prolonging the duration of nerve blocks. However, it is uncertain whether its effects are due to local effects on the nerves or from systemic absorption. This systematic review aimed to compare the duration of postoperative analgesia associated with perineural versus intravenous dexamethasone as an adjunct to peripheral nerve blocks. Methods: A total of 2,216 relevant academic articles were identified after a comprehensive search of PubMed, Embase, Scopus, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov from 1967 until 2020. All randomized controlled trials that compared perineural and intravenous dexamethasone as adjuncts to peripheral nerve limb blocks were included.Results: Fifteen randomized controlled trials (1,467 cases; 738 perineural dexamethasone, 729 intravenous dexamethasone) were eligible. The primary outcome (duration of analgesia) was significantly longer in the perineural than in the intravenous dexamethasone group (mean difference [MD]: 2.72 h, 95% CI [1.42, 4.01], P < 0.001). Perineural dexamethasone was also found to prolong the sensory block (MD: 3.45 h, 95% CI [1.36, 5.54], P = 0.001) and lower 24 h postoperative pain scores (MD: −0.74 h, 95% CI [−1.40, −0.07], P = 0.03).Conclusions: This review confirms the greater efficacy of perineural compared to intravenous dexamethasone in prolonging the analgesic duration of peripheral nerve blocks. However, the extent of prolongation was small and may not represent a clinically meaningful difference.

Thoracolumbar Injury Classification and Severity Score Is Predictive of Perioperative Adverse Events in Operatively Treated Thoracic and Lumbar Fractures

Liu Gabriel Ka-Po,Tan Jiong Hao,Kong Jun Cheong,Tan Yong Hao Joel,Kumar Nishant,Liang Shen,Shawn Seah Jing Sheng,Ting Chiu Shi,Lim Lau Leok,Dennis Hey Hwee Weng,Kumar Naresh,Thambiah Joseph,Wong Hee-K 대한척추외과학회 2022 Asian Spine Journal Vol.16 No.6

Study Design: A retrospective cohort study of patients with surgically treated thoracolumbar fractures.Purpose: This study aimed to describe the incidence of adverse events (AEs) after surgical stabilization of thoracolumbar spine injuries and to identify predictive factors for the occurrence of AEs. Overview of Literature: Thoracolumbar spine fractures are frequently present in patients with blunt trauma and are associated with significant morbidity. AEs can occur due to the initial spinal injury or secondary to surgical treatment. There is a lack of emphasis in the literature on the AEs that can occur after operative management of thoracolumbar fractures.Methods: We performed a retrospective review of 199 patients with surgically treated thoracolumbar fractures operated between January 2007 and January 2018. The potential risk factors for the development of AEs as well as the development of common complications were evaluated by univariate analysis, and a multivariate logistic regression analysis was performed to identify independent risk factors predictive of the above.Results: The overall rate of AEs was 46.7%; 83 patients (41.7%) had nonsurgical AEs, whereas 24 (12.1%) had surgical adverse events. The most common AEs were urinary tract infections in 43 patients (21.6%), and hospital-acquired pneumonia in 21 patients (10.6%). On multivariate logistic regression, a Thoracolumbar Injury Classification and Severity (TLICS) score of 8–10 (odds ratio [OR], 6.39; 95% confidence interval [CI], 2.33–17.51), the presence of polytrauma (OR, 2.64; 95% CI, 1.17–5.99), and undergoing open surgery (OR, 2.31; 95% CI, 1.09–4.88) were significant risk factors for AEs. The absence of neurological deficit was associated with a lower rate of AEs (OR, 0.47; 95% CI, 0.31–0.70).Conclusions: This study suggests the presence of polytrauma, preoperative American Spinal Injury Association score, and TLICS score are predictive of AEs in patients with surgically treated thoracolumbar fractures. The results might also suggest a role for minimally invasive surgical methods in reducing AEs in these patients.

Geochemical and S isotopic studies of pollutant evolution in groundwater after acid in situ leaching in a uranium mine area in Xinjiang

Liu Zhenzhong,Tan Kaixuan,Li Chunguang,Li Yongmei,Zhang Chong,Song Jing,Liu Longcheng 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.4

Laboratory experiments and point monitoring of reservoir sediments have proven that stable sulfate reduction (SSR) can lower the concentrations of toxic metals and sulfate in acidic groundwater for a long time. Here, we hypothesize that SSR occurred during in situ leaching after uranium mining, which can impact the fate of acid groundwater in an entire region. To test this, we applied a sulfur isotope fractionation method to analyze the mechanism for natural attenuation of contaminated groundwater produced by acid in situ leaching of uranium (Xinjiang, China). The results showed that δ34S increased over time after the cessation of uranium mining, and natural attenuation caused considerable, area-scale immobilization of sulfur corresponding to retention levels of 5.3%–48.3% while simultaneously decreasing the concentration of uranium. Isotopic evidence for SSR in the area, together with evidence for changes of pollutant concentrations, suggest that area-scale SSR is most likely also important at other acid mining sites for uranium, where retention of acid groundwater may be strengthened through natural attenuation. To recapitulate, the sulfur isotope fractionation method constitutes a relatively accurate tool for quantification of spatiotemporal trends for groundwater during migration and transformation resulting from acid in situ leaching of uranium in northern China.

Making a Traditional Spine Surgery Clinic Telemedicine-Ready in the “New Normal” of Coronavirus Disease 2019

Liu Ka-Po Gabriel,Tan Wei Loong Barry,Yip Wei Luen James,Tan Jun-Hao,Wong Hee-Kit 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.2

Study Design: An original article describing a comprehensive methodology for making a traditional spine surgery clinic telemedicineready in terms of logistical considerations and workflow.Purpose: The aim of this study is to promote the use of telemedicine via videoconferencing to reduce human exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and reduce the risk of coronavirus disease 2019 (COVID-19) transmission at outpatient clinics.Overview of Literature: The COVID-19 pandemic is the biggest healthcare crisis in the 21st century. Until a vaccine is developed or herd immunity against SARS-CoV-2 is achieved, social distancing to avoid crowding is an important strategy to reduce disease transmission and resurgence. Telemedicine has already been applied in the field of orthopedics with encouraging results.Methods: We reviewed the evidence behind telemedicine and described our clinical protocol, patient selection criteria, and workflow for telemedicine. We discussed a simple methodology to convert pre-existing traditional clinic resources into telemedicine tools, along with future challenges.Results: Our methodology was successfully and easily applied in our clinical practice, with a streamlined workflow allowing our spine surgery service to implement telemedicine as a consultation modality in line with the national recommendations of social distancing.Conclusions: Telemedicine was well incorporated into our outpatient practice using the above workflow. We believe that the use of telemedicine via videoconferencing can become part of the new normal and a safe strategy for healthcare systems as both a medical and an economic countermeasure against COVID-19.

Effect of temperature and spring-mass systems on modal properties of Timoshenko concrete beam

Liu, Hanbing,Wang, Hua,Tan, Guojin,Wang, Wensheng,Liu, Ziyu Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.65 No.4

An exact solution for the title problem was obtained in closed-form fashion considering general boundary conditions. The expressions of moment, shear and shear coefficient (or shear factor) of cross section under the effect of arbitrary temperature distribution were first derived. In view of these relationships, the differential equations of Timoshenko beam under the effect of temperature were obtained and solved. Second, the characteristic equations of Timoshenko beam carrying several spring-mass systems under the effect of temperature were derived based on the continuity and force equilibrium conditions at attaching points. Then, the correctness of proposed method was demonstrated by a Timoshenko laboratory beam and several finite element models. Finally, the influence law of different temperature distribution modes and parameters of spring-mass system on the modal characteristics of Timoshenko beam had been studied, respectively.

Polymorphisms in Epigenetic and Meat Quality Related Genes in Fourteen Cattle Breeds and Association with Beef Quality and Carcass Traits

Liu, Xuan,Usman, Tahir,Wang, Yachun,Wang, Zezhao,Xu, Xianzhou,Wu, Meng,Zhang, Yi,Zhang, Xu,Li, Qiang,Liu, Lin,Shi, Wanhai,Qin, Chunhua,Geng, Fanjun,Wang, Congyong,Tan, Rui,Huang, Xixia,Liu, Airong,Wu, Asian Australasian Association of Animal Productio 2015 Animal Bioscience Vol.28 No.4

Improvement for carcass traits related to beef quality is the key concern in beef production. Recent reports found that epigenetics mediates the interaction of individuals with environment and nutrition. The present study was designed to analyze the genetic effect of single nucleotide polymorphisms (SNPs) in seven epigenetic-related genes (DNMT1, DNMT3a, DNMT3b, DNMT3L, Ago1, Ago2, and HDAC5) and two meat quality candidate genes (CAPN1 and PRKAG3) on fourteen carcass traits related to beef quality in a Snow Dragon beef population, and also to identify SNPs in a total of fourteen cattle populations. Sixteen SNPs were identified and genotyped in 383 individuals sampled from the 14 cattle breeds, which included 147 samples from the Snow Dragon beef population. Data analysis showed significant association of 8 SNPs within 4 genes related to carcass and/or meat quality traits in the beef populations. SNP1 (13154420A>G) in exon 17 of DNMT1 was significantly associated with rib-eye width and lean meat color score (p<0.05). A novel SNP (SNP4, 76198537A>G) of DNMT3a was significantly associated with six beef quality traits. Those individuals with the wild-type genotype AA of DNMT3a showed an increase in carcass weight, chilled carcass weight, flank thicknesses, chuck short rib thickness, chuck short rib score and in chuck flap weight in contrast to the GG genotype. Five out of six SNPs in DNMT3b gene were significantly associated with three beef quality traits. SNP15 (45219258C>T) in CAPN1 was significantly associated with chuck short rib thickness and lean meat color score (p<0.05). The significant effect of SNP15 on lean meat color score individually and in combination with each of other 14 SNPs qualify this SNP to be used as potential marker for improving the trait. In addition, the frequencies of most wild-type alleles were higher than those of the mutant alleles in the native and foreign cattle breeds. Seven SNPs were identified in the epigenetic-related genes. The SNP15 in CAPN1 could be used as a powerful genetic marker in selection programs for beef quality improvement in the Snow Dragon Beef population.

Substitution of Wheat for Corn in Beef Cattle Diets: Digestibility, Digestive Enzyme Activities, Serum Metabolite Contents and Ruminal Fermentation

Liu, Y.F.,Zhao, H.B.,Liu, X.M.,You, W.,Cheng, H.J.,Wan, F.C.,Liu, G.F.,Tan, X.W.,Song, E.L.,Zhang, X.L. Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.10

The objective of this study was to evaluate the effect of diets containing different amounts of wheat, as a partial or whole substitute for corn, on digestibility, digestive enzyme activities, serum metabolite contents and ruminal fermentation in beef cattle. Four Limousin${\times}$LuXi crossbred cattle with a body weight ($400{\pm}10kg$), fitted with permanent ruminal, proximal duodenal and terminal ileal cannulas, were used in a $4{\times}4$ Latin square design with four treatments: Control (100% corn), 33% wheat (33% substitution for corn), 67% wheat (67% substitution for corn), and 100% wheat (100% substitution for corn) on a dry matter basis. The results showed that replacing corn with increasing amounts of wheat increased the apparent digestibility values of dry matter, organic matter, and crude protein (p<0.05). While the apparent digestibility of acid detergent fiber and neutral detergent fiber were lower with increasing amounts of wheat. Digestive enzyme activities of lipase, protease and amylase in the duodenum were higher with increasing wheat amounts (p<0.05), and showed similar results to those for the enzymes in the ileum except for amylase. Increased substitution of wheat for corn increased the serum alanine aminotransferase concentration (p<0.05). Ruminal pH was not different between those given only corn and those given 33% wheat. Increasing the substitution of wheat for corn increased the molar proportion of acetate and tended to increase the acetate-to-propionate ratio. Cattle fed 100% wheat tended to have the lowest ruminal $NH_3-N$ concentration compared with control (p<0.05), whereas no differences were observed among the cattle fed 33% and 67% wheat. These findings indicate that wheat can be effectively used to replace corn in moderate amounts to meet the energy and fiber requirements of beef cattle.

Morphological effects on surface-enhanced Raman scattering from silver butterfly wing scales synthesized via photoreduction.

Tan, Yongwen,Zang, Xining,Gu, Jiajun,Liu, Dingxin,Zhu, Shenmin,Su, Huilan,Feng, Chuanliang,Liu, Qinglei,Lau, Woon Ming,Moon, Won-Jin,Zhang, Di American Chemical Society 2011 Langmuir Vol.27 No.19

<P>Through a simple room-temperature photoreduction process, this letter conformally replicates 3D submicrometer structures of wing scales from two butterfly species into Ag to generate practical surface-enhanced Raman scattering (SERS) substrates. The Ag replicas of butterfly scales with higher structural periodicity are able to detect rhodamine 6G at a low concentration down to 10(-9) M, which is three orders of magnitude lower than the detectable concentration limit of using quasi-periodic Ag butterfly structures. This result presents a way to select suitable scale morphologies from 174,500 species of Lepidopterans to replicate, as consumable SERS substrates with low cost and high reproducibility.</P>

Effects of Ribosomal Protein L39-L on the Drug Resistance Mechanisms of Lung Cancer A549 Cells

Liu, Hong-Sheng,Tan, Wen-Bin,Yang, Ning,Yang, Yuan-Yuan,Cheng, Peng,Liu, Li-Juan,Wang, Wei-Jie,Zhu, Chang-Liang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.7

Background: Cancer is a major threat to the public health whether in developed or in developing countries. As the most common primary malignant tumor, the morbidity and mortality rate of lung cancer continues to rise in recent ten years worldwide. Chemotherapy is one of the main methods in the treatment of lung cancer, but this is hampered by chemotherapy drug resistance, especially MDR. As a component of the 60S large ribosomal subunit, ribosomal protein L39-L gene was reported to be expressed specifically in the human testis and human cancer samples of various tissue origins. Materials and Methods: Total RNA of cultured drug-resistant and susceptible A549 cells was isolated, and real time quantitative RT-PCR were used to indicate the transcribe difference between amycin resistant and susceptible strain of A549 cells. Viability assay were used to show the amycin resistance difference in RPL39-L transfected A549 cell line than control vector and null-transfected A549 cell line. Results: The ribosomal protein L39-L transcription level was 8.2 times higher in drug-resistant human lung cancer A549 cell line than in susceptible A549 cell line by quantitative RT-PCR analysis. The ribosomal protein L39-L transfected cells showed enhanced drug resistance compared to plasmid vector-transfected or null-transfected cells as determined by methyl tritiated thymidine (3H-TdR) incorporation. Conclusions and Implications for Practice: The ribosomal protein L39-L gene may have effects on the drug resistance mechanism of lung cancer A549 cells.