High frequency acoustic emission monitoring in nano-impact of bulk ceramics

Acoustic Emission (AE) monitoring is proving a powerful technique in improving our understanding of deformation processes occurring at the nano- and micro-scale [1-3]. The recent development of advanced high frequency AE sensor systems and their integration to commercial nanomechanical test instrumentation has been a catalyst for research into damage processes in scratching thin films [2,3]. In recent studies AE detection revealed the onset of cracking otherwise undetectable but subsequently confirmed by FIB sectioning. In this current study the high frequency AE technique has been used to investigate the cracking behavior of bulk technical ceramics (MgO-partially stabilized zirconia (PSZ) and zirconia-toughened alumina (ZTA)) at low strain rate in nanoindentation and at higher strain rate in the nano-impact test. Although both ceramics were susceptible to indentation or impact-induced cracking it was more prevalent on PSZ. The influence of accelerating force and probe geometry were explored in the higher strain rate tests with cube-corner and 5 mm radius spherical diamond indenters. Large bursts of AE were observed at the abrupt displacement step in repetitive impact with a cube corner but were generally much smaller/absent during other impact events. The AE response with the 5 mm radius probe was quite different with smaller displacement events and AE bursts on most impacts at higher load. References [1] Indentation testing and its acoustic emission response: applications and emerging trends, N.H. Faisal, R. Ahmed and R.L. Reuben, International Materials Reviews 56 (2011) 98. [2] On the importance of combined scratch/acoustic emission test evaluation: SiC and SiCN thin films case study, J. Tomastik et al, Coatings 8 (2018) 196 [3] Effect of nitrogen doping and temperature on mechanical durability of silicon carbide thin films, J. Tomastik et al, Sci Rep 8 (2018) 10428

The dynamics of telomere length in primary and metastatic colorectal cancer lesions

Abstract Telomeric sequences, the structures comprised of hexanucleotide repeats and associated proteins, play a pivotal role in chromosome end protection and preservation of genomic stability. Herein we address telomere length (TL) dynamics in primary colorectal cancer (CRC) tumour tissues and corresponding liver metastases. TL was measured by multiplex monochrome real-time qPCR in paired samples of primary tumours and liver metastases along with non-cancerous reference tissues obtained from 51 patients diagnosed with metastatic CRC. Telomere shortening was observed in the majority of primary tumour tissues compared to non-cancerous mucosa (84.1%, p < 0.0001). Tumours located within the proximal colon had shorter TL than those in the rectum (p < 0.05). TL in liver metastases was not significantly different from that in primary tumours (p = 0.41). TL in metastatic tissue was shorter in the patients diagnosed with metachronous liver metastases than in those diagnosed with synchronous liver metastases (p = 0.03). The metastatic liver lesions size correlated with the TL in metastases (p < 0.05). Following the neoadjuvant treatment, the patients with rectal cancer had shortened telomeres in tumour tissue than prior to the therapy (p = 0.01). Patients with a TL ratio between tumour tissue and the adjacent non-cancerous mucosa of ≥ 0.387 were associated with increased overall survival (p = 0.01). This study provides insights into TL dynamics during progression of the disease. The results show TL differences in metastatic lesions and may help in clinical practice to predict the patient’s prognosis

Rivaroxaban with or without aspirin in stable cardiovascular disease

BACKGROUND: We evaluated whether rivaroxaban alone or in combination with aspirin would be more effective than aspirin alone for secondary cardiovascular prevention. METHODS: In this double-blind trial, we randomly assigned 27,395 participants with stable atherosclerotic vascular disease to receive rivaroxaban (2.5 mg twice daily) plus aspirin (100 mg once daily), rivaroxaban (5 mg twice daily), or aspirin (100 mg once daily). The primary outcome was a composite of cardiovascular death, stroke, or myocardial infarction. The study was stopped for superiority of the rivaroxaban-plus-aspirin group after a mean follow-up of 23 months. RESULTS: The primary outcome occurred in fewer patients in the rivaroxaban-plus-aspirin group than in the aspirin-alone group (379 patients [4.1%] vs. 496 patients [5.4%]; hazard ratio, 0.76; 95% confidence interval [CI], 0.66 to 0.86; P<0.001; z=−4.126), but major bleeding events occurred in more patients in the rivaroxaban-plus-aspirin group (288 patients [3.1%] vs. 170 patients [1.9%]; hazard ratio, 1.70; 95% CI, 1.40 to 2.05; P<0.001). There was no significant difference in intracranial or fatal bleeding between these two groups. There were 313 deaths (3.4%) in the rivaroxaban-plus-aspirin group as compared with 378 (4.1%) in the aspirin-alone group (hazard ratio, 0.82; 95% CI, 0.71 to 0.96; P=0.01; threshold P value for significance, 0.0025). The primary outcome did not occur in significantly fewer patients in the rivaroxaban-alone group than in the aspirin-alone group, but major bleeding events occurred in more patients in the rivaroxaban-alone group. CONCLUSIONS: Among patients with stable atherosclerotic vascular disease, those assigned to rivaroxaban (2.5 mg twice daily) plus aspirin had better cardiovascular outcomes and more major bleeding events than those assigned to aspirin alone. Rivaroxaban (5 mg twice daily) alone did not result in better cardiovascular outcomes than aspirin alone and resulted in more major bleeding events