Prediction of HAZ Microstructure and Hardness for Q960E Joints Welded by Triple-Wire GMAW Based on Thermal and Numerical Simulation

Since heat affected zone (HAZ) is the weak area of welded joints, this article proposes a method to predict the HAZ microstructure and hardness for the triple-wire gas metal arc welding (GMAW) process of Q960E high strength steel. This method combines welding thermal simulation and numerical simulation. The microstructures and hardness of Q960E steel under different cooling rates were obtained by thermal simulation and presented in a simulated HAZ continuous cooling transformation (SH-CCT) diagram. The cooling rate in HAZ were obtained by numerical simulation with ANSYS software for the triple-wire welding of Q960E thick plates. By comparing the cooling rate with the SH-CCT diagram, the microstructure and hardness of the HAZ coarse-grained region were accurately predicted for multiple heat input conditions. Further, an ideal heat input was chosen by checking the prediction results. This prediction method not only helps us to optimize the welding parameters, but also leads to an overall understanding of the process-microstructure-performance for a complex welding process.     

BACTEC-MGIT960快速培养药敏对肺结核诊治的应用和评价

目的　BACTEC-MGIT960快速培养药敏在肺结核诊治中的应用评价。方法 采用BACTEC-MGIT960进行快速培养药敏,并与改良罗氏培养基和改良7H9培养基进行比较。结果 BACTEC-MGIT960培养报告时间仅8.5d,明显短于改良7H9培养基(20.6d)和改良罗氏培养基(30.8d)。BACTEC-MGIT960药物敏感试验结果与其它检测方法相比,符合率在90%以上,平均报告时间仅6.5d,明显短于改良7H9培养基(17d)和改良罗氏培养基(26.5d)。结论 BACTEC-MGIT960快速培养药敏有助于肺结核的诊断和治疗,是一种快速、有效、可靠的方法。     

BACTEC MGIT 960培养结合INNO-LIPA~(TM) RIF.TBDNA探针新技术快速诊断结核病

目的通过MGIT960培养系统结合国外最新的INNO -LIPATM RIF.TB(LIPA)DNA探针技术的应用 ,探讨其快速诊断结核病的可行性。方法应用BACTECMGIT960系统进行临床疑似结核病例标本的培养 ,筛选了70例结核分枝杆菌 ,35例非结核分枝杆菌 ,用LIPA探针技术诊断是否为结核分枝杆菌。结果用LIPADNA方法在70例结核分枝杆菌中获得阳性69例 ,占98.6 % ;35例非结核分枝杆菌均为阴性。与单纯消化纯化后涂片的82.9 % (58/70)的阳性率相比增加了15.7个百分点 ,两者在统计学上差异有显著性(P<0.05)。BactecMGIT960培养结合LIPADNA探针与传统诊断方法4～8周相比 ,整个过程只需6～37天 ,平均15天 (2周 )。结论LIPADNA探针是一种具有高度敏感性和特异性、能够简便、快速、准确地诊断结核病的新技术。同时还能鉴定rpoβ 基因位点的突变 ,诊断耐利福平 (RMP)性结核 ,有望适用于结核分枝杆菌耐RMP性结核的快速检测 ,进一步为结核病快速准确的治疗提供理论依据。     

BACTEC MGIT 960仪在肺结核病诊断中的应用

[目的]探讨BACTEC MGIT 960仪在肺结核病诊断中的应用。[方法]应用BACTEC MGIT 960仪对肺结核病人的痰标本进行培养，并与BACTEC TB 460仪、改良罗氏培养法及涂片抗酸染色法进行对照。[结果]BACTEC MGIT 960仪阳性率为31．96％，与BACTEC TB 460仪的阳性率接近，比改良罗氏培养法及涂片抗酸染色法高。[结论]BACTEC MGIT 960仪能显著缩短（初代阳性平均分离时间为11．6d，比BACTEC TB 460仪快1．9d，比改良罗氏培养法快9．1d。）报告时间，且阳性检出率高。     

Plasma abnormal prothrombin (PIVKA-π): A new and reliable marker for the detection of hepatocellular carcinoma

We evaluated the clinical usefulness of a protein induced by vitamin K absence, antagonist-prothrombin (PIVKA-II), in detecting hepatocellular carcinoma (HCC) specifically in patients with liver cirrhosis, and the possible correlation between levels of PIVKA-II and pathological features of HCC. Plasma levels of PIVKA-II and alpha-fetoprotein (AFP) were measured in 628 patients with various diseases, including 253 with liver cirrhosis and 116 with HCC. PIVKA-II was detected (greater than or equal to 0.1 arbitrary unit/mL) in 54.3% of HCC and the concentration showed a positive correlation with the tumour size. As a screening test for the detection of HCC, PIVKA-II produced values comparable with those of AFP with a sensitivity, specificity and validity of 52.8, 98.8 and 51.6% respectively. Sixteen of 45 patients (37%) with HCC who had low AFP (less than 100 ng/mL) levels were positive for PIVKA-II. No apparent relationship, however, could be found between the levels of PIVKA-II and the aetiology or pathological findings of HCC. These results suggest that PIVKA-II can be a reliable marker for detecting HCC in patients with liver cirrhosis.     

Relationship between ototoxicity of aminoglycoside antibiotics and their transferability into inner ear fluids

The purpose of this study is to clarify the question whether the difference of severity of ototoxicity induced by the aminoglycoside antibiotics depends on the difference of quantity of transferability into inner ear. Aminoglycoside antibiotics (tobramycin, kanamycin, netilmicin and ribostamycin) were injected for 30 consecutive days to rabbits. The relationship between the severity of hair cell damage and concentration of antibiotics in perilymph was investigated. The drug concentration in the perilymph was determined by the bioassay method, and using the surface preparation technique the hair cell damage was observed under a phase contrast microscope. It was concluded that the difference of severity of ototoxicity induced by the aminoglycoside antibiotics is due to the difference of their own toxicity to hair cells but not to the difference of their transferability into the perilymph.     

微阵列芯片技术在结核分枝杆菌耐药性检测中的应用

目的 评价微阵列芯片法与BACTEC MGIT 960液体药敏（简称MGIT960药敏）、罗氏比例法药敏（简称罗氏比例法）在结核分枝杆菌（MTB）对异烟肼（INH）、利福平（RFP）药敏试验检测方面的差异,用于指导临床用药。方法 选择医院临床科室2016年3月—2017年11月期间确诊及疑似结核病的住院和门诊患者标本,同时采用微阵列芯片法、MGIT960药敏和罗氏比例法对其进行结核分枝杆菌检测,选择3种方法检测均为阳性的446例患者标本进行异烟肼和利福平药敏检测,比较三者检测结果的差异性。结果 分别以MGIT960药敏结果和罗氏比例法为参照,微阵列芯片法检测MTB对异烟肼耐药性的灵敏度分别为84.8%和83.5%、特异度分别为99.7%和98.5%、Kappa值分别0.885和0.855,对利福平耐药性的灵敏度分别为96.2%和93.7%、特异度分别为93.8%和93.5%、Kappa值分别为0.817和0.796,表明微阵列芯片法和另外两种方法对异烟肼和利福平耐药性的检测具有极好的一致性;此外,MGIT960药敏和罗氏比例法药敏不一致的MTB样本采用微阵列芯片法检测,结果显示,MGIT960药敏和罗氏比例法分别与微阵列芯片法比较,利福平的耐药性符合率分别为77.8%和88.9%,异烟肼的耐药性符合率分别为100.0%和75.0%,表明两种表型药敏不一致的MTB样本可能存在异质性耐药。结论 微阵列芯片法与MGIT960药敏和罗氏比例法药敏比较,对异烟肼和利福平耐药性检测具有极好的一致性,具有快速、精准、较高的灵敏度和特异度,对于表型药敏不一致的临床样本采用微阵列芯片法检测,可对其进行验证并为临床上异质性耐药的治疗提供更好的实验室依据。     

基质辅助激光解吸电离飞行时间质谱技术对分枝杆菌液体培养系统菌种鉴定的临床研究

目的 应用基质辅助激光解吸电离飞行时间质谱(matrix assisted laser desorption ionization time of flight mass spectrometry,MALDI-TOF MS)对Bactec^TM MGIT^TM 960液体培养出的阳性培养物进行高通量、快速、准确的菌种鉴定,为临床早期、精准治疗提供病原学依据。方法 选取我院Bactec^TM MGIT^TM 960分枝杆菌快速液体培养的阳性培养物为研究对象,通过不同的孵育时间、不同大小的研磨珠处理、不同的破壁方式摸索出MALDI-TOF MS对Bactec^TM MGIT^TM 960阳性培养物鉴定的“最优处理方法”,并将所有结果与基因芯片法菌种鉴定做参照进行比对,鉴定不一致的结果通过基因测序确认。结果 Bactec^TM MGIT^TM 960液体培养报阳性后增加孵育时间可提高检出率及鉴定分值,同时使用0.5 mm的氧化锆珠研磨,使用超声震荡混匀处理,鉴定效果最佳。鉴定结果方面,液体系统报阳的420份阳性标本,基因芯片法鉴定结果为结核分枝杆菌占69.05%(290/420),非结核菌占28.81% (121/420),9例未鉴定出,未鉴定占2.14%(9/420),错误鉴定占0.95%(4/420),总鉴定率为97.86%(411/420);采用MALDI-TOF MS质谱鉴定420份阳性标本中鉴定出419例,其中结核分枝杆菌占69.05%(290/420),非结核占30.00%(126/420),星型奴卡菌0.48%(2/420),巴西奴卡菌占0.24%(1/420),1例未鉴定出,总鉴定率为99.76%。质谱鉴定分值≥2.0的400例占95.24%,分值在1.7~2.0的19例占4.52%,分值<1.7的1例占0.24%。结论 本实验实现了Bactec^TM MGIT^TM 960液体培养阳性培养物的直接质谱鉴定,缩短了培养鉴定的时间,将分枝杆菌鉴定到种水平,能区分出结核菌与非结核菌,同时也能将与分枝杆菌相似的奴卡菌鉴定出来,对临床疾病的鉴别诊断起到了积极的作用。     

Effect of Neutralization of Gastric Aspirate on culture yield of mycobacterium tuberculosis in children with pulmonary tuberculosis

IntroductionConventionally gastric aspirates are neutralized with sodium bicarbonate to improve the culture yield of MTB. However, only limited data is there to support this practice. The aim of this study was to compare the contamination rate, culture yield and time to detection of Mycobacterium tuberculosis (MTB) in neutralized and non-neutralized gastric aspirate samples and report the drug resistance.Materials and methodsA total of 336 neutralized and non-neutralized gastric aspirate samples were simultaneously cultured by both LJ culture and MGIT 960 to compare the difference in isolation rate, time to detection and contamination rate. First line drug susceptibility testing was performed using MGIT 960 SIRE kit.ResultsMTB was isolated from 8.6% (29/336) of GA samples by one or more of the culture methods. The isolation rate of MTB from neutralized and non-neutralized GA samples by combined LJ and MGIT 960 culture was 7.1% (24/336) and 6.8% (23/336), respectively. Both of them detected 18 MTB isolates in common. However, the neutralized and non-neutralized GA samples detected additional 6 and 5 MTB isolates, respectively. The mean time to detection of MTB were similar. In MGIT 960 culture, contamination rate of non-neutralized samples (17%) was significantly lower when compared to neutralized samples (21.1%) (P = 0.044). Drug susceptibility testing of MTB isolates revealed that, out of 26 isolates, 2 were resistant to ethambutol, one each was resistant to isoniazid and rifampicin.ConclusionThe findings of this study suggest that non-neutralized samples should be routinely processed in addition to the neutralized samples for optimum isolation of MTB from gastric aspirate samples.     

Ventilator-associated pneumonia: impact of organisms on clinical resolution and medical resources utilization

BACKGROUND: Clinical resolution of ventilator-associated pneumonia (VAP) determines the duration of treatment and mechanical ventilation. The aim of this study was to evaluate the influence of organisms and their susceptibility to treatment on outcomes. METHODS: Prospective observational study in three teaching ICUs. Sixty episodes of VAP with appropriate therapy (Haemophilus influenzae, 15 episodes; methicillin-sensitive Staphylococcus aureus [MSSA], 15 episodes; Pseudomonas aeruginosa, 15 episodes; and methicillin-resistant S aureus [MRSA], 15 episodes), and 30 episodes with initial inappropriate therapy, all due to P aeruginosa, were compared. The main outcome measures were clinical resolution variables and, in survivors, length of mechanical ventilation after VAP onset. RESULTS: A significant delay in the resolution of hypoxemia was observed in VAP episodes due to MRSA and P aeruginosa with inappropriate antibiotic therapy (IAT) (median time to resolution, 10 and 8 days, respectively) when compared with the remaining pathogens (median time to resolution, 2 days). A multiple regression model, adjusted for disease severity, confirmed the delayed clinical resolution for MRSA and P aeruginosa with IAT. Similar associations were documented for defervescence. Among survivors, the median duration of mechanical ventilation after VAP onset was significantly longer for MRSA (17 days) and P aeruginosa IAT (11 days) when compared with episodes due to H influenzae or MSSA (6 days). Multiple regression analysis, adjusted for disease severity, confirmed that MRSA required significantly (R(2) = 0.132; p < 0.01) longer respiratory support than other organisms. CONCLUSIONS: When treated promptly, the resolution of VAP due to MSSA, H influenzae, and P aeruginosa was comparable. The resolution of MRSA VAP, regardless of the appropriateness of initial antibiotic therapy, was associated with longer respiratory support.