Determining Curie temperature of (Ga,Mn)As samples based on electrical transport measurements: low Curie temperature case

In this paper we show that the widely accepted method of the determination of Curie temperature (TC) in (Ga,Mn)As samples, based on the position of the peak in the temperature derivative of the resistivity,completely fails in the case of non-metallic and low-TC unannealed samples. In this case we propose an alternative method, also based on electric transport measurements, which exploits temperature dependence of the second derivative of the resistivity upon magnetic field.Comment: 5 pages, 3 figure

Helicobacter pylori cytotoxin-associated gene A virulence and its association with the epithelial-mesenchymal transition in gastric cancer

Gastric cancer is currently one of the most prevalent malignancies worldwide with a high mortality rate. Helicobacter pylori (H. pylori) infection significantly contributes to the onset and progression of gastric cancer mainly due to the induction of chronic inflammatory responses. The pathogenicity of H. pylori is associated with a vast number of virulence factors among which cytotoxin-associated gene A (CagA) plays a crucial role. We conducted a literature review of PubMed, Web of Science, and Scopus on September 1st, 2021. There were no limits regarding the year and the language of publication. Articles included in this review concerned human and animal studies. The following search string was applied during the search: (gastric cancer) AND (epithelial-mesenchymal transition) AND (Helicobacter pylori) AND (cytotoxin-associated gene A). The final analysis included 135 articles independently reviewed by the authors. H. pylori CagA-positive strains seem to be more virulent compared to the CagA-negative strains. CagA pathogenicity includes the increased secretion of pro-inflammatory cytokines, induction of cancer stem cell-like properties, apoptosis prevention, or overactivation of particular oncogenic pathways. H. pylori might induce epithelial-mesenchymal transition (EMT) via numerous pathways, among which CagA-related pathogenicity is considered to be of high significance. Mechanisms associated with CagA action are involved in the maintenance of chronic H. pylori infection, subsequent EMT induction, and further onset and progression of gastric cancer. Because of a huge number of H. pylori strains with different virulence mechanisms, the clinical outcome of patients is also associated with the particular type of strain that infected a patient

FMSiSP Test

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Galvanomagnetic methods of Curie temperature determination in (Ga,Mn)As

We critically discuss various experimental methods to determine Curie temperature TC of (Ga,Mn)As thin layers or other conducting magnetic materials by means of electric charge transport measurements. They all base on the influence of sample magnetization on the magnetoresistivity tensor ρ̂ and are an alternative to the method based upon an analysis of the temperature derivative of the sample resistance (Novák et al., 2008). These methods can be applied even when standard SQUID magnetometers are difficult or impossible to use – for example for extremely small samples or in the case of experiments performed at very specific physical conditions, e.g. at high hydrostatic pressure inside the clamp cell. We show that the use of the so called Arrott plot prepared with the use of high magnetic field isotherms ρxx(H0),ρxy(H0) (H0 – external magnetic field) may lead to substantial (of the order of 10 K) divergence of the obtained TC values depending on the assumptions which are necessary to make in this case and depending on the direction of a magnetic anisotropy easy axis. We also propose a number of ways how to obtain, basing on low magnetic field isotherms ρxx(H0),ρxy(H0), clear and characteristic features which are closely related to the ferromagnetic–paramagnetic phase transition

The Involvement of Human Papilloma Virus in Gastrointestinal Cancers

Human Papilloma Virus (HPV) is one of the most common sexually transmitted infections worldwide. HPV infection has a strong relationship with the onset of cervix uteri, vagina, penis, anus, and oropharynx, but also tonsils and tongue cancers. Some epidemiological data indicate that except for gynecologic cancers, HPV infection can be one of the risk factors associated with a greater risk of induction and progression of gastrointestinal cancers. Data, however, remain contradictory and definite conclusions cannot be drawn, so far. The following review aims to organize recent evidence and summarize the current state of knowledge regarding the association between HPV infection and gastrointestinal tumors primarily focusing on esophageal, liver, gastric, colorectal, and anal cancers

WNT3a and WNT5a Transported by Exosomes Activate WNT Signaling Pathways in Human Cardiac Fibroblasts

WNT signaling plays an important role in fibrotic processes in the heart. Recently, exosomes have been proposed as novel extracellular transporters for WNT proteins. In this study, we analyzed whether WNT3a and WNT5a carried by exosomes could activate downstream molecular pathways in human cardiac fibroblasts. Exosomes were isolated from conditioned medium of control, WNT3a- and WNT5a-producing L cells by differential ultracentrifugations. Obtained exosomes showed size ranging between 20⁻150 nm and expressed exosomal markers ALG-2-interacting protein X (ALIX) and CD63. Treatment with WNT3a-rich exosomes inhibited activity of glycogen synthase kinase 3β (GSK3β), induced nuclear translocation of β-catenin, and activated T-cell factor (TCF)/lymphoid enhancer factor (LEF) transcription factors as well as expression of WNT/β-catenin responsive genes in cardiac fibroblasts, but did not coactivate extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and activator protein 1 (AP-1) signaling pathways. In contrast, exosomes produced by WNT5a-producing L cells failed to activate β-catenin-dependent response, but successfully triggered phosphorylation of ERK1/2 and JNK and stimulated IL-6 production. In conclusion, exosomes containing WNT proteins can functionally contribute to cardiac fibrosis by activating profibrotic WNT pathways on cardiac fibroblasts and may represent a novel mechanism of spreading profibrotic signals in the heart

WNT3a and WNT5a Transported by Exosomes Activate WNT Signaling Pathways in Human Cardiac Fibroblasts

WNT signaling plays an important role in fibrotic processes in the heart. Recently, exosomes have been proposed as novel extracellular transporters for WNT proteins. In this study, we analyzed whether WNT3a and WNT5a carried by exosomes could activate downstream molecular pathways in human cardiac fibroblasts. Exosomes were isolated from conditioned medium of control, WNT3a- and WNT5a-producing L cells by differential ultracentrifugations. Obtained exosomes showed size ranging between 20–150 nm and expressed exosomal markers ALG-2-interacting protein X (ALIX) and CD63. Treatment with WNT3a-rich exosomes inhibited activity of glycogen synthase kinase 3β (GSK3β), induced nuclear translocation of β-catenin, and activated T-cell factor (TCF)/lymphoid enhancer factor (LEF) transcription factors as well as expression of WNT/β-catenin responsive genes in cardiac fibroblasts, but did not coactivate extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and activator protein 1 (AP-1) signaling pathways. In contrast, exosomes produced by WNT5a-producing L cells failed to activate β-catenin-dependent response, but successfully triggered phosphorylation of ERK1/2 and JNK and stimulated IL-6 production. In conclusion, exosomes containing WNT proteins can functionally contribute to cardiac fibrosis by activating profibrotic WNT pathways on cardiac fibroblasts and may represent a novel mechanism of spreading profibrotic signals in the heart