Uncovering the crystallography and formation mechanism of nanoscale clusters in Sb-rich SPPs of a p-type (Bi, Sb)2Te3 alloy.

Considering that the crystallographic characteristics of the Sb-rich secondary phase particles (SPPs) greatly affect the thermoelectric properties of Bi2Te3 based materials, it is of great significance to explore the mechanism behind the Sb-rich SPPs in the p-type (Bi, Sb)2Te3 material. Here a conventional TEM technique was used to characterize the composition, size and distribution of Sb-rich SPPs in a spark plasma sintered p-type (Bi, Sb)2Te3 alloy. The results indicated that two different morphologies of Sb-rich SPPs including elongated and circular Sb-rich SPPs were frequently observed. Combined with high-resolution transmission electron microscopy, this work provides atomic-scale evidence for the formation mechanism behind the Sb-rich SPPs in the (Bi, Sb)2Te3 material.

The histologic features, molecular features, detection and management of serrated polyps: a review.

The serrated pathway to colorectal cancers (CRCs) is a significant pathway encompassing five distinct types of lesions, namely hyperplastic polyps (HPs), sessile serrated lesions (SSLs), sessile serrated lesions with dysplasia (SSL-Ds), traditional serrated adenomas (TSAs), and serrated adenoma unclassified. In contrast to the conventional adenoma-carcinoma pathway, the serrated pathway primarily involves two mechanisms: BRAF/KRAS mutations and CpG island methylator phenotype (CIMP). HPs are the most prevalent non-malignant lesions, while SSLs play a crucial role as precursors to CRCs, On the other hand, traditional serrated adenomas (TSAs) are the least frequently encountered subtype, also serving as precursors to CRCs. It is crucial to differentiate these lesions based on their unique morphological characteristics observed in histology and colonoscopy, as the identification and management of these serrated lesions significantly impact colorectal cancer screening programs. The management of these lesions necessitates the crucial steps of removing premalignant lesions and implementing regular surveillance. This article provides a comprehensive summary of the epidemiology, histologic features, molecular features, and detection methods for various serrated polyps, along with recommendations for their management and surveillance.

Causal association between telomere length and colorectal polyps: A bidirectional two-sample Mendelian randomization study.

We performed a bidirectional 2-sample Mendelian randomization (MR) design to explore the causal relation between telomere length (TL) and colorectal polyps. Genome-wide association study summary data of TL and colorectal polyps were extracted from the IEU open genome-wide association study database. Single nucleotide polymorphisms were served as instrumental variables at the significance threshold of P < 5 × 10-8. The inverse variance weighted method, MR-Egger method, and weight median method were performed for causal estimation in MR. Cochran Q test, MR-Egger intercept test, and leave-one-out analyses were performed to evaluate the pleiotropy of the MR results. One hundred and twenty-four single nucleotide polymorphisms were selected as instrumental variables. We found significant casual association between TL and colorectal polyps. Long TL increased the risk of colorectal polyps using the inverse variance weighted method [ukb-a-521: odds ratio (OR): 1.004, 95% confidence interval (CI): 1.001-1.007, P = .004; ukb-d-D12: OR: 1.008, CI: 1.004-1.012, P < .001; finn-b-CD2_BENIGN_COLORECANI_EXALLC2: OR: 1.170, CI: 1.027-1.332, P = .018]. Sensitivity analyses validated that the causality between TL and colorectal polyps was robust. The study provided a causal association between TL and colorectal polyps which indicated that TL might be served as a potential biomarker of colorectal polyps for screening and prevention. Nonetheless, the conclusions need further validation.

Transitional structure of {0001} twin in a deformed p-type (Bi,Sb)2Te3 alloy: a direct experimental basis for understanding the twinning mechanism.

Twin boundaries provide a strong phonon scattering center to hinder the lattice thermal conductivity in thermoelectric materials, but the underlying evolution process of deformation twinning remains to be figured out. By applying atomic resolution transmission electron microscope (TEM) observations, a novel type of transitional structure of {0001} twin was observed, for the first time, in the p-type (Bi,Sb)2Te3 alloy subjected to three-point bending deformation. The transformation from matrix to (0001) twin can be realized by the following path: matrix → transitional twin → (0001) twin, and this process was completed by the gliding of a total of four partial dislocations (b1 = 1/3[011̄0]) extended in the different (0001) planes. This new finding here will shed light on the nucleation and growth of deformation twins in the p-type (Bi, Sb)2Te3 alloy.

Stacking faults in Zr(Fe, Cr)2 Laves structured secondary phase particle in Zircaloy-4 alloy.

Stacking faults (SFs) in secondary phase particles (SPPs), which generally crystallize in the Laves phase in Zircaloy-4 (Zr-4) alloy, have been frequently observed by researchers. However, few investigations on the nano-scale structure of SFs have been carried out. In the present study, an SF containing C14 structured SPP, which located at grain boundaries (GBs) in the α-Zr matrix, was chosen to be investigated, for its particular substructure as well as location, aiming to reveal the nature of the SFs in the SPPs in Zr-4 alloy. It was indicated that the SFs in the C14 structured SPP actually existed in the local C36 structured Laves phase, for their similarities in crystallography. The C14 → C36 phase transformation, which was driven by synchroshearing among the (0001) basal planes, was the formation mechanism of the SFs in the SPPs. By analyzing the strained regions near the SPP, a model for understanding the driving force of the synchroshear was proposed: the interaction between SPP and GB resulted in the Zener pinning effect, leading to the shearing parallel to the (0001) basal planes of the C14 structured SPP, and the synchroshear was therefore activated.

Considerable knock-on displacement of metal atoms under a low energy electron beam.

Under electron beam irradiation, knock-on atomic displacement is commonly thought to occur only when the incident electron energy is above the incident-energy threshold of the material in question. However, we report that when exposed to intense electrons at room temperature at a low incident energy of 30 keV, which is far below the theoretically predicted incident-energy threshold of zirconium, Zircaloy-4 (Zr-1.50Sn-0.25Fe-0.15Cr (wt.%)) surfaces can undergo considerable displacement damage. We demonstrate that electron beam irradiation of the bulk Zircaloy-4 surface resulted in a striking radiation effect that nanoscale precipitates within the surface layer gradually emerged and became clearly visible with increasing the irradiation time. Our transmission electron microscope (TEM) observations further reveal that electron beam irradiation of the thin-film Zircaly-4 surface caused the sputtering of surface α-Zr atoms, the nanoscale atomic restructuring in the α-Zr matrix, and the amorphization of precipitates. These results are the first direct evidences suggesting that displacement of metal atoms can be induced by a low incident electron energy below threshold. The presented way to irradiate may be extended to other materials aiming at producing appealing properties for applications in fields of nanotechnology, surface technology, and others.

Elevated expression of KLK8 predicts poor prognosis in colorectal cancer.

KLK8, also known as neuropsin, is one of fifteen members of the human kallikrein-related peptidase (KLK) gene family, which consists of enzymes with serine protease enzymatic activity. Aberrant KLK8 expression has been reported in several malignancies. However, the clinicopathological significance and prognostic value of KLK8 expression in colorectal cancer (CRC) are unknown. Therefore, analysis of public datasets, quantitative real-time PCR and western blot analysis were performed to assess KLK8 expression in CRC at both the mRNA and protein level. KLK8 expression was also assessed by immunohistochemistry in a tissue microarray containing 124 CRC specimens. We observed that KLK8 was overexpressed in CRC tissues and was significantly associated with TNM stage, vascular invasion, differentiation and AJCC stage. Univariate and multivariate Cox analyses confirmed that KLK8 is a significant independent prognostic factor for both DFS and OS. Cell function assays also indicated that KLK8 could facilitate CRC cell proliferation, migration and invasion in vitro. In conclusion, elevated KLK8 expression was correlated with the progression of CRC and is a potential independent prognostic indicator for CRC.