Polytypism and Superconductivity in the NbS2_2 System

We report on the phase formation and the superconducting properties in the NbS$_2$ system. Specifically, we have performed a series of standardized solid-state syntheses in this system, which allow us to establish a comprehensive synthesis map for the formation of the two polytypes 2H-NbS$_2$ and 3R-NbS$_2$, respectively. We show that the identification of two polytypes by means of X-ray diffraction is not always unambiguous. Our physical property measurements on a phase-pure sample of 3R-NbS$_2$, on a phase-pure sample of 2H-NbS$_2$, and a mixed phase sample confirm earlier reports that 2H-NbS$_2$ is a bulk superconductor and that 3R-NbS$_2$ is not a superconductor above $T =$ 1.75 K. Our results clearly show that specific heat measurements, as true bulk measurements, are crucial for the identification of superconducting materials in this and related systems. Our results indicate that for the investigation of van-der-Waals materials great care has to be taken on choosing the synthesis conditions for obtaining phase pure samples.Comment: https://pubs.rsc.org/en/content/articlelanding/2021/dt/d0dt03636f#!divAbstrac

Matrix metalloproteinases-2, -7 and tissue metalloproteinase inhibitor-1 expression in human endometrium

Introduction. Endometrium undergoes regular, cyclic tissue remodeling mostly associated to the endocrine system status. It is well-known fact that steroid hormones are strongly responsible for changes in endometrium. The precise mechanism of their action is still under investigation. The aim of the study was to evaluate the expression of metalloproteinases 2 and 7 (MMP-2, -7) and tissue inhibitor of metalloproteinase 1 (TIMP-1) in human endometrium in relation to serum concentrations of estradiol and progesterone during different phases of menstrual cycle.Material and methods. The study material consisted of 52 biopsy samples; 12 obtained in the proliferative phase, 11 in the secretory phase and 29 during menstruation. Expression of MMP-2, MMP-7 and TIMP-1 was assessed by immunohistochemistry. Serum concentrations of estradiol and progesterone at time of biopsy were evaluated by immunochemistry assay. Results of the study were statistically assessed by linear regression model.Results. Increased serum concentration of estradiol was associated with increased MMP-2 expression in proliferative phase but decreased in secretory phase and during menstruation. No significant relationship was found between progesterone concentration and MMP-2 expression. Moreover, no difference in the expression of MMP-7 and TIMP-1 in the endometrium in relation to hormone levels and menstrual cycle phases were observed.Conclusions. The results of the study indicate that estradiol influence MMP-2 expression in the endometrium depends on the phase of menstrual cycle. Such relationships were not found for MMP-7 and TIMP-1 and further tests clarifying association between estradiol and MMPs are needed.

Deleted in Liver Cancer 2 (DLC2) protein expression in hepatocellular carcinoma

Deleted in Liver Cancer (DLC) proteins belong to the family of RhoGAPs and are believed to operate as negative regulators of the Rho family of small GTPases. So far, the role of the first identified member from the DLC family, DLC1, was established as a tumor suppressor in hepatocellular carcinoma. The function of its close family relative, DLC2 is unequivocal. In the present study we attempted to determine whether the loss of DLC2 is a common feature of hepatocellular carcinoma tissue. We examined two types of hepatocellular carcinoma- typical and fibrolamellar one. Our analysis revealed that DLC2 protein is not diminished in cancer tissue when compared to non-cancerous liver specimens. What is more, we observed DLC2 to be more abundantly expressed in cancer tissue, particularly in tumors with the inflammation background. In addition, we found that DLC2 gene status was diploid in virtually all tumor samples examined. Our results indicate that DLC2 is not diminished in hepatocellular carcinoma cells. It appears that members of the DLC family, although structurally highly related, may function differently in cancer cells

(NH4)2AgX3 (X = Br, I): 1D Silver Halides with Broadband White Light Emission and Improved Stability

Recently, ternary copper(I) halides have emerged as alternatives to lead halide perovskites for light emission applications. Despite their high-efficiency photoluminescence (PL) properties, most copper(I) halides are blue emitters with unusually poor tunability of their PL properties. Here, we report the impact of substitution of copper with silver in the high-efficiency blue-emitting Cu(I) halides through hydrothermal synthesis and characterization of (NH4)2AgX3 (X = Br, I). (NH4)2AgX3 are found to exhibit contrasting light emission properties compared to the blue-emitting Cu(I) analogues. Thus, (NH4)2AgBr3 and (NH4)2AgI3 exhibit broadband whitish light emission at room temperature with PL maxima at 394 and 534 nm and full width at half-maximum values of 142 and 114 nm, respectively. Based on our combined experimental and computational results, the broadband emission in (NH4)2AgX3 is attributed to the presence of high-stability self-trapped excitons and defect-bound excitons. (NH4)2AgBr3 and (NH4)2AgI3 both have significantly improved air and moisture stability as compared to the related copper(I) halides, which are prone to degradation via oxidation. Our results suggest that silver halides should be considered alongside their copper analogues for high-efficiency light emission applications.This material is based upon work supported by the National Aeronautics and Space Administration under Agreement No.80NSSC19M0140 issued through NASA Oklahoma EPSCoR.M.-H.D. was supported by the U.S. Department of Energy,Office of Science, Basic Energy Sciences, Materials Sciences,and Engineering Division. Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.Ye

Loss of the Orphan Nuclear Receptor SHP Is More Pronounced in Fibrolamellar Carcinoma than in Typical Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) remains a major problem in oncology. The molecular mechanisms which underlie its pathogenesis are poorly understood. Recently the Small Heterodimer Partner (SHP), an orphan nuclear receptor, was suggested to be involved as a tumor suppressor in hepatocellular carcinoma development. To date, there are no such studies regarding fibrolamellar carcinoma, a less common variant of HCC, which usually affects young people and displays distinct morphological features. The aim of our project was to evaluate the SHP levels in typical and fibrolamellar hepatocellular carcinoma with respect to the levels of one of the cell cycle regulators, cyclin D1. We assessed the immunoreactivity levels of SHP and cyclin D1 in 48 typical hepatocellular carcinomas, 9 tumors representing the fibrolamellar variant, 29 non malignant liver tissues and 7 macroregenerative nodules. We detected significantly lower SHP immunoreactivity in hepatocellular carcinoma when compared to non malignant liver tissue. Moreover, we found that SHP immunoreactivity is reduced in fibrolamellar carcinoma when compared to typical hepatocellular carcinoma. We also found that SHP is more commonly lost in HCC which arises in the liver with steatosis. The comparison between the cyclin D1 and SHP expression revealed the negative correlation between these proteins in the high grade HCC. Our results indicate that the impact of loss of SHP protein may be even more pronounced in fibrolamellar carcinoma than in a typical form of HCC. Further investigation of mechanisms through which the loss of SHP function may influence HCC formation may provide important information in order to design more effective HCC therapy

Genomic Characterization of Cholangiocarcinoma in Primary Sclerosing Cholangitis Reveals Therapeutic Opportunities

Background and Aims Lifetime risk of biliary tract cancer (BTC) in primary sclerosing cholangitis (PSC) may exceed 20%, and BTC is currently the leading cause of death in patients with PSC. To open new avenues for management, we aimed to delineate clinically relevant genomic and pathological features of a large panel of PSC-associated BTC (PSC-BTC). Approach and Results We analyzed formalin-fixed, paraffin-embedded tumor tissue from 186 patients with PSC-BTC from 11 centers in eight countries with all anatomical locations included. We performed tumor DNA sequencing at 42 clinically relevant genetic loci to detect mutations, translocations, and copy number variations, along with histomorphological and immunohistochemical characterization. Regardless of the anatomical localization, PSC-BTC exhibited a uniform molecular and histological characteristic similar to extrahepatic cholangiocarcinoma. We detected a high frequency of genomic alterations typical of extrahepatic cholangiocarcinoma, such asTP53(35.5%),KRAS(28.0%),CDKN2A(14.5%), andSMAD4(11.3%), as well as potentially druggable mutations (e.g.,HER2/ERBB2). We found a high frequency of nontypical/nonductal histomorphological subtypes (55.2%) and of the usually rare BTC precursor lesion, intraductal papillary neoplasia (18.3%). Conclusions Genomic alterations in PSC-BTC include a significant number of putative actionable therapeutic targets. Notably, PSC-BTC shows a distinct extrahepatic morpho-molecular phenotype, independent of the anatomical location of the tumor. These findings advance our understanding of PSC-associated cholangiocarcinogenesis and provide strong incentives for clinical trials to test genome-based personalized treatment strategies in PSC-BTC.Peer reviewe