The excellent cryogenic tensile properties of the CrMnFeCoNi alloy are generally caused by deformation twinning, which is difficult to achieve at room temperature because of insufficient stress for ...twinning. Here, we induced twinning at room temperature to improve the cryogenic tensile properties of the CrMnFeCoNi alloy. Considering grain size effects on the critical stress for twinning, twins were readily formed in the coarse microstructure by cold rolling without grain refinement by hot rolling. These twins were retained by partial recrystallization and played an important role in improving strength, allowing yield strengths approaching 1 GPa. The persistent elongation up to 46% as well as the tensile strength of 1.3 GPa are attributed to additional twinning in both recrystallized and non-recrystallization regions. Our results demonstrate that non-recrystallized grains, which are generally avoided in conventional alloys because of their deleterious effect on ductility, can be useful in achieving high-strength high-entropy alloys.
Abstract
We introduce a novel transformation-induced plasticity mechanism,
i
.
e
., a martensitic transformation from fcc phase to bcc phase, in medium-entropy alloys (MEAs). A VCrFeCoNi MEA system ...is designed by thermodynamic calculations in consideration of phase stability between bcc and fcc phases. The resultantly formed bcc martensite favorably contributes to the transformation-induced plasticity, thereby leading to a significant enhancement in both strength and ductility as well as strain hardening. We reveal the microstructural evolutions according to the Co-Ni balance and their contributions to a mechanical response. The Co-Ni balance plays a leading role in phase stability and consequently tunes the cryogenic-temperature strength-ductility balance. The main difference from recently-reported metastable high-entropy dual-phase alloys is the formation of bcc martensite as a daughter phase, which shows significant effects on strain hardening. The hcp phase in the present MEA mostly acts as a nucleation site for the bcc martensite. Our findings demonstrate that the fcc to bcc transformation can be an attractive route to a new MEA design strategy for improving cryogenic strength-ductility.
BACKGROUND AND PURPOSEThe safety and efficacy of tirofiban during endovascular therapy in patients undergoing intravenous thrombolysis with recombinant IV tPA remain unclear. This study aimed to ...investigate the safety and efficacy of intra-arterial tirofiban use during endovascular therapy in patients treated with IV tPA. MATERIALS AND METHODSUsing a multicenter registry, we enrolled patients with acute ischemic stroke who underwent endovascular therapy. Safety outcomes included postprocedural parenchymal hematoma type 2 and/or thick subarachnoid hemorrhage, intraventricular hemorrhage, and 3-month mortality. Efficacy outcomes included the successful reperfusion rate, postprocedural reocclusion, and good outcomes at 3 months (mRS scores of 0-2). The tirofiban effect on the outcomes was evaluated using a multivariable analysis while adjusting for potential confounders. RESULTSAmong enrolled patients, we identified 314 patients with stroke (279 and 35 patients in the no tirofiban and tirofiban groups, respectively) due to an intracranial artery occlusion who underwent endovascular therapy with intravenous thrombolysis. A multivariable analysis revealed no association of intra-arterial tirofiban with postprocedural parenchymal hematoma type and/or thick subarachnoid hemorrhage (adjusted OR, 1.07; 95% CI, 0.20-4.10; P = .918), intraventricular hemorrhage (adjusted OR, 0.43; 95% CI, 0.02-2.85; P = .467), and 3-month mortality (adjusted OR, 0.38; 95% CI, 0.04-1.87; P = .299). Intra-arterial tirofiban was not associated with good outcome (adjusted OR, 2.22; 95% CI, 0.89 -6.12; P = .099). CONCLUSIONSUsing intra-arterial tirofiban during endovascular therapy after IV tPA could be safe.
To determine the frequency of cerebellar infarction mimicking vestibular neuritis (VN), the pattern of clinical presentation, and the territory of the cerebellar infarction when it simulates VN.
We ...studied 240 consecutive cases of isolated cerebellar infarction in the territories of the cerebellar arteries diagnosed by brain MRI from the acute stroke registry at the Keimyung University Dongsan Medical Center.
We identified 25 patients (10.4%) with isolated cerebellar infarction who had clinical features suggesting VN. Two types of cerebellar infarction simulating VN were found: isolated spontaneous prolonged vertigo with imbalance as a sole manifestation of cerebellar infarction (n = 24) and isolated spontaneous prolonged vertigo with imbalance as an initial manifestation of cerebellar infarction (n = 1) followed by delayed neurologic deficits 2 days after the onset. The cerebellar infarction territory most commonly involved was the medial branch of the posterior inferior cerebellar artery territory (24/25: 96%), followed by the anterior inferior cerebellar artery territory (1/25: 4%). None of patients with infarcts in the territory of the superior cerebellar artery or multiple cerebellar arteries showed isolated spontaneous prolonged vertigo.
Cerebellar infarction simulating vestibular neuritis is more common than previously thought. Early recognition of the pseudo-vestibular neuritis of vascular cause may allow specific management.
Background
Laparoscopic colorectal resection has become popular. The recently developed da Vinci Surgical System promises to facilitate endoscopic surgery and overcome its disadvantages. This study ...therefore aimed to compare the short-term results between robotic tumor-specific mesorectal excision (R-TSME) using the da Vinci Surgical System and conventional laparoscopic tumor-specific mesorectal excision (L-TSME) in rectal cancer patients.
Methods
Between April 2006 and February 2007, 36 patients were randomly assigned to receive R-TSME or L-TSME. During the study, 18 patients underwent robotic low anterior resection using the da Vinci Surgical System, and 18 patients had conventional laparoscopic low anterior resection. Patient characteristics, perioperative clinical results, complications, and pathologic details were compared between the two groups.
Results
The patient characteristics were not significantly different between the two groups. The mean operating time, hemoglobin change, and conversion rate were not significantly different between the groups. Complications were treated conservatively and did not require surgical intervention in the R-TSME group. The average length of stay was 6.9 ± 1.3 days in the R-TSME group and 8.7 ± 1.3 days in the L-TSME group (
p
< 0.001). The specimen quality of the R-TSME group was acceptable.
Conclusion
Tumor-specific mesorectal excision was performed safely and effectively using the da Vinci Surgical System and the perioperative outcomes were acceptable.
Abstract
α-ketoglutarate (KG), also referred to as 2-oxoglutarate, is a key intermediate of cellular metabolism with pleiotropic functions. Cell-permeable esterified analogs are widely used to study ...how KG fuels bioenergetic and amino acid metabolism and DNA, RNA, and protein hydroxylation reactions, as cellular membranes are thought to be impermeable to KG. Here we show that esterified KG analogs rapidly hydrolyze in aqueous media, yielding KG that, in contrast to prevailing assumptions, imports into many cell lines. Esterified KG analogs exhibit spurious KG-independent effects on cellular metabolism, including extracellular acidification, arising from rapid hydrolysis and de-protonation of α-ketoesters, and significant analog-specific inhibitory effects on glycolysis or mitochondrial respiration. We observe that imported KG decarboxylates to succinate in the cytosol and contributes minimally to mitochondrial metabolism in many cell lines cultured in normal conditions. These findings demonstrate that nuclear and cytosolic KG-dependent reactions may derive KG from functionally distinct subcellular pools and sources.
We introduce a novel transformation-induced plasticity mechanism, i.e., a martensitic transformation from fcc phase to bcc phase, in medium-entropy alloys (MEAs). A VCrFeCoNi MEA system is designed ...by thermodynamic calculations in consideration of phase stability between bcc and fcc phases. The resultantly formed bcc martensite favorably contributes to the transformation-induced plasticity, thereby leading to a significant enhancement in both strength and ductility as well as strain hardening. We reveal the microstructural evolutions according to the Co-Ni balance and their contributions to a mechanical response. The Co-Ni balance plays a leading role in phase stability and consequently tunes the cryogenic-temperature strength-ductility balance. The main difference from recently-reported metastable high-entropy dual-phase alloys is the formation of bcc martensite as a daughter phase, which shows significant effects on strain hardening. The hcp phase in the present MEA mostly acts as a nucleation site for the bcc martensite. Our findings demonstrate that the fcc to bcc transformation can be an attractive route to a new MEA design strategy for improving cryogenic strength-ductility.
Lysophosphatidic acid (LPA) is a biolipid that has diverse biological activities implicated in ovarian cancer initiation and progression. Previous studies have shown the critical role of the ...Rho/Rho-associated kinase (ROCK) pathway in LPA-induced ovarian cancer progression. However, detailed underlying mechanism by which the Rho/ROCK pathway induces ovarian cancer cell invasion is still incompletely understood. In the present study, we observed that the Rho/ROCK pathway is implicated in the production of proteolytic enzymes, leading to LPA-induced ovarian cancer cell invasion. LPA induced matrix metalloproteinase (MMP)-9 expression in CAOV-3 and PA-1 cells and urokinase-type plasminogen activator (uPA) expression in SKOV-3 cells. LPA-induced proteolytic enzyme expression was required for the invasion of ovarian cancer cells expressing corresponding enzymes. Pretreatment of cells with a pharmacological inhibitor of Rho/ROCK (Y-27632) or overexpression of a dominant-negative mutant of Rho (Rho N19) profoundly inhibited LPA-induced proteolytic enzyme expression as well as the invasive potential of ovarian cancer cells. In addition, transfection with dominant-negative Ras (Ras N17) significantly inhibited LPA-induced Rho activation as well as MMP-9 and uPA expression. Consistently, Y-27632 reduced LPA-induced nuclear factor (NF)-κB activation that is critical for proteolytic enzyme expression and cellular invasion. Collectively, we demonstrate a mechanism by which LPA promotes ovarian cancer progression through coordinate activation of a Ras/Rho/ROCK/NF-κB signaling pathway and the proteolytic enzyme secretion, providing novel biomarkers and promising therapeutic targets for ovarian cancer cell progression.
This national survey was undertaken to propose the classification of extranodal natural killer (NK)/T-cell lymphoma (NTCL) subtypes and to clarify a clinical heterogeneity.
Two hundred and eighty ...patients newly diagnosed as NTCL were enrolled from 22 Korean medical centers. Two subsets were compared: one involving the upper aerodigestive tract (UAT) and another involving the non-upper aerodigestive tract (NUAT) region, which comprises the skin, gastrointestinal tract, and liver or soft tissues. Clinical prognostic factors, survival outcomes, and independent predictors for survival were compared between each subset.
NUAT-NTCL (59 patients) had significantly higher proportions of disseminated disease, aggressive biologic features, and unfavorable host reactions compared with UAT-NTCL (221 patients). NUAT-NTCL had shortened 5-year overall survival (OS) (22% versus 41%, P = 0.001). Ann Arbor staging, the International Prognostic Index, and the NTCL prognostic index failed to predict the OS of NUAT-NTCL, but did predict the OS in UAT-NTCL. Independent predictors for OS by multivariate analyses differed between each subset. In the NUAT subset, extranodal sites and regional nodes predicted the OS, while Ann Arbor staging, age, performance status, and lactate dehydrogenase level predicted the OS in the UAT subset.
NUAT-NTCL may represent a distinctive disease entity in terms of clinical factors, independent predictors, and survival outcomes.
The establishment of better selection criteria for identifying sub-populations that may benefit from treatment is a key aspect of the development and success of targeted therapy. To investigate ...methods for assessing MET overexpression in gastric cancer, we conducted immunohistochemistry using a new anti-Total MET monoclonal antibody in a single-institution cohort of 495 patients. As antibody is directed against a membranous and/or cytoplasmic epitope, two interpretation methods were used: (1) membranous and cytoplasmic and (2) membranous alone. In selected 120 cases, copy number gain and mRNA expression levels were measured using quantitative real-time PCR. Further in situ hybridization confirmed the presence of MET gene amplification. Among the 495 gastric cancers, simultaneous membranous and cytoplasmic overexpression of MET was found in 108 cases (21.8%) and membranous alone overexpression was observed in 40 cases (8.1%). The highest correlation was observed in membranous and cytoplasmic staining of MET: MET expression scores correlated significantly with high MET mRNA levels (r=0.465, P<0.0001), increased copy number gain (r=0.393, P=0.000002) and amplification of MET gene. Moreover, patients with MET overexpression showed shorter overall survival (HR, 1.781; 95% CI, 1.324-2.395; P<0.001) and disease-free survival (HR, 1.765; 95% CI, 1.227-2.541; P=0.002) compared with patients without MET overexpression. However, membranous overexpression of MET did not highly correlate with mRNA level (r=0.274, P=0.002), copy number gain or survival (P>0.05). We developed highly correlating interpretation methods of MET immunohistochemistry in gastric carcinomas. MET overexpression is an independent prognostic factor and could be a potential target and predictor of benefit for targeted therapy with MET inhibitors.
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