Electronic Raman Scattering in Twistronic Few-Layer Graphene.

We study electronic contribution to the Raman scattering signals of two-, three- and four-layer graphene with layers at one of the interfaces twisted by a small angle with respect to each other. We find that the Raman spectra of these systems feature two peaks produced by van Hove singularities in moiré minibands of twistronic graphene, one related to direct hybridization of the Dirac states, and the other resulting from band folding caused by moiré superlattice. The positions of both peaks strongly depend on the twist angle, so that their detection can be used for noninvasive characterization of the twist, even in hBN-encapsulated structures.

Receptor Tyrosine Kinase Expression Profiles in Canine Cutaneous and Subcutaneous Mast Cell Tumors.

The receptor tyrosine kinase (RTK) KIT is a major focus of current research into canine mast cell tumors (MCTs). Little is known about the role of other RTKs, such as vascular endothelial growth factor receptors (VEGFRs) and platelet-derived growth factor receptors (PDGFRs). These RTKs are dysregulated in many human and animal cancers and are key regulators of tumor angiogenesis. The aims of this study were to assess the expression and activation (phosphorylation) status of KIT, VEGFR2, and PDGFR (α and ß) in canine MCTs and to examine associations with various clinical outcomes. c-KITmutational status and KIT cellular localization pattern were also evaluated for these tumors. Twenty-seven MCTs, consisting of 5 subcutaneous and 22 cutaneous tumors, from 25 dogs were evaluated. MCT biopsies, cultured mast cells, and skin from the surgical margin were analyzed through Western blotting. MCT biopsies were also used for KIT immunohistochemical labeling and polymerase chain reaction for c-KITmutational analysis. MCT had heterogeneous expression profiles for all 3 RTKs, which varied in intensity and activation status. Statistical analyses showed phosphorylated KIT, VEGFR2, and KIT cellular localization to be predictive of decreased survival time, disease-free interval, and increased metastatic rate. Expression of VEGFR2 and KIT diffuse cytoplasmic labeling were also significantly associated with increased rate of local recurrence. The results of the study show that phosphorylated KIT, KIT, VEGFR2, and PDGFRß, in addition to KIT localization, may be valuable prognostic determinants in MCTs and should be further studied to improve diagnostic and therapeutic modalities.

Canine subcutaneous mast cell tumor: characterization and prognostic indices.

Histologic grading schemes for canine cutaneous mast cell tumors (MCTs) were not developed for subcutaneous MCTs. Despite this, subcutaneous MCTs are currently categorized by many as grade II or higher. The aim of this investigation was to assess the pathology and clinical outcome for subcutaneous MCTs to provide a more accurate prognosis. Information on clinical outcome for 306 dogs was obtained from veterinarians and correlated with histologic features. Mean and median follow-up was 842 and 891 days, respectively (range, 3-2,305 days). Only 27 (9%) were confirmed as mast cell-related deaths. Metastasis occurred in 13 (4%), and 24 (8%) had local reoccurrence, even though 171 (56%) cases had incomplete surgical margins. Median survival time was not reached, and the estimated 6-month, 1-, 2-, and 5-year survival probabilities were 95%, 93%, 92%, and 86%, respectively. Dogs were euthanized or died as a result of local tumor reoccurrence, additional MCT development distant to the surgical site, or metastasis. Decreased survival time was linked to mitotic index (number of mitotic figures per 10 high-power fields), infiltrative growth pattern, and presence of multinucleation. Both univariable and multivariable analysis showed mitotic index to be strongly predictive of survival, local reoccurrence, and metastasis. The results of the study indicate that the majority of subcutaneous MCTs have a favorable prognosis, with extended survival times and low rates of reoccurrence and metastasis.

Canine subcutaneous mast cell tumors: cellular proliferation and KIT expression as prognostic indices.

Molecular assays are widely used to prognosticate canine cutaneous mast cell tumors (MCT). There is limited information about these prognostic assays used on MCT that arise in the subcutis. The aims of this study were to evaluate the utility of KIT immunohistochemical labeling pattern, c-KIT mutational status (presence of internal tandem duplications in exon 11), and proliferation markers--including mitotic index, Ki67, and argyrophilic nucleolar organizing regions (AgNOR)--as independent prognostic markers for local recurrence and/or metastasis in canine subcutaneous MCT. A case-control design was used to analyze 60 subcutaneous MCT from 60 dogs, consisting of 24 dogs with subsequent local recurrence and 12 dogs with metastasis, as compared to dogs matched by breed, age, and sex with subcutaneous MCT that did not experience these events. Mitotic index, Ki67, the combination of Ki67 and AgNOR, and KIT cellular localization pattern were significantly associated with local recurrence and metastasis, thereby demonstrating their prognostic value for subcutaneous MCT. No internal tandem duplication mutations were detected in exon 11 of c-KIT in any tumors. Because c-KIT mutations have been demonstrated in only 20 to 30% of cutaneous MCT and primarily in tumors of higher grade, the number of subcutaneous MCT analyzed in this study may be insufficient to draw conclusions on the role c-KIT mutations in these tumors.

Determination of interatomic coupling between two-dimensional crystals using angle-resolved photoemission spectroscopy.

Lack of directional bonding between two-dimensional crystals like graphene or monolayer transition metal dichalcogenides provides unusual freedom in the selection of components for vertical van der Waals heterostructures. However, even for identical layers, their stacking, in particular the relative angle between their crystallographic directions, modifies properties of the structure. We demonstrate that the interatomic coupling between two two-dimensional crystals can be determined from angle-resolved photoemission spectra of a trilayer structure with one aligned and one twisted interface. Each of the interfaces provides complementary information and together they enable self-consistent determination of the coupling. We parametrise interatomic coupling for carbon atoms by studying twisted trilayer graphene and show that the result can be applied to structures with different twists and number of layers. Our approach demonstrates how to extract fundamental information about interlayer coupling in a stack of two-dimensional crystals and can be applied to many other van der Waals interfaces.

Right on track? Performance of satellite telemetry in terrestrial wildlife research.

Satellite telemetry is an increasingly utilized technology in wildlife research, and current devices can track individual animal movements at unprecedented spatial and temporal resolutions. However, as we enter the golden age of satellite telemetry, we need an in-depth understanding of the main technological, species-specific and environmental factors that determine the success and failure of satellite tracking devices across species and habitats. Here, we assess the relative influence of such factors on the ability of satellite telemetry units to provide the expected amount and quality of data by analyzing data from over 3,000 devices deployed on 62 terrestrial species in 167 projects worldwide. We evaluate the success rate in obtaining GPS fixes as well as in transferring these fixes to the user and we evaluate failure rates. Average fix success and data transfer rates were high and were generally better predicted by species and unit characteristics, while environmental characteristics influenced the variability of performance. However, 48% of the unit deployments ended prematurely, half of them due to technical failure. Nonetheless, this study shows that the performance of satellite telemetry applications has shown improvements over time, and based on our findings, we provide further recommendations for both users and manufacturers.

Myeloid translocation genes differentially regulate colorectal cancer programs.

Myeloid translocation genes (MTGs), originally identified as chromosomal translocations in acute myelogenous leukemia, are transcriptional corepressors that regulate hematopoietic stem cell programs. Analysis of The Cancer Genome Atlas (TCGA) database revealed that MTGs were mutated in epithelial malignancy and suggested that loss of function might promote tumorigenesis. Genetic deletion of MTGR1 and MTG16 in the mouse has revealed unexpected and unique roles within the intestinal epithelium. Mtgr1-/- mice have progressive depletion of all intestinal secretory cells, and Mtg16-/- mice have a decrease in goblet cells. Furthermore, both Mtgr1-/- and Mtg16-/- mice have increased intestinal epithelial cell proliferation. We thus hypothesized that loss of MTGR1 or MTG16 would modify Apc1638/+-dependent intestinal tumorigenesis. Mtgr1-/- mice, but not Mtg16-/- mice, had a 10-fold increase in tumor multiplicity. This was associated with more advanced dysplasia, including progression to invasive adenocarcinoma, and augmented intratumoral proliferation. Analysis of chromatin immunoprecipitation sequencing data sets for MTGR1 and MTG16 targets indicated that MTGR1 can regulate Wnt and Notch signaling. In support of this, immunohistochemistry and gene expression analysis revealed that both Wnt and Notch signaling pathways were hyperactive in Mtgr1-/- tumors. Furthermore, in human colorectal cancer (CRC) samples MTGR1 was downregulated at both the transcript and protein level. Overall our data indicates that MTGR1 has a context-dependent effect on intestinal tumorigenesis.

Identification of cryptic peanut agglutinin-reactive sites in human lipoprotein(a).

After treatment of human lipoprotein(a) (Lp(a)) with neuraminidase, formerly cryptic sites became available for binding to peanut agglutinin (PNA) lectin and a Thomsen-Friedenreich antigen (T-antigen)-specific monoclonal antibody. The PNA-reactive sites were localized to the apo(a) moiety of Lp(a) and O-specific carbohydrate side chains. Lp(a) with larger isoforms of apo(a) contained more potential PNA reactivity per molecule of Lp(a) apoB than did smaller isoforms. Very low density lipoproteins (VLDL), low density lipoproteins (LDL), and high density lipoproteins (HDL) did not contain comparable amounts of the cryptic PNA-reactive sites.

Production and characterization of a monoclonal antibody to dog hepatic lipase.

Partially purified dog hepatic lipase was used as antigen to produce monoclonal antibodies in mice. In addition to enzyme-linked immunosorbent assay (ELISA), a reliable and efficient procedure for screening antibodies reacting to hepatic lipase has been developed. A method to distinguish antibodies directing to active site or non-active site epitopes has also been described. We obtained three positive clones that survived after subcloning and expansion. All three monoclonal antibodies possess gamma one (gamma 1) heavy chains and kappa (kappa) light chains. Specificity of monoclonal antibody LDHL No. 537 to dog hepatic lipase was demonstrated by passing post-heparin plasma through its immunoaffinity column. Only dog hepatic lipase was removed by LDHL No. 537 from post-heparin plasma. The immunoaffinity chromatography also demonstrated the co-existence of three enzyme activities (mono- and triacylglycerol lipase and phospholipase A1) on the dog hepatic lipase molecule. The subunit weight of dog hepatic lipase has been estimated at 57500 +/- 600 (n=3) by using immunoaffinity chromatography and the combination of immunoprecipitation and autoradiography methods.

Viral induction, transmission and apoptosis among cells infected by a Human Intracisternal A-type retrovirus.

Sjogren's Syndrome, a systemic autoimmune disease, is characterized by lymphocytic infiltration of the salivary or lacrimal glands, producing xerostomia or xerophthalmia. Although definitive proof of viral etiology has not been established, a cell line containing viral particles termed Human Intracisternal A-type Particles (HIAP) resulted from co-culture with patient lip biopsies. We stimulated these chronically infected cells with phorbol myristate acetate (PMA) in an effort to enhance production of viral particles for further characterization. We report that the virus present in the HIAP cell line can be induced to become lytic when subjected to PMA and that there is a difference in the effects of PMA on H9 and HIAP cell groups, with apparent protection from apoptosis due to PMA being exerted by viral presence. Delayed apoptosis may prolong exposure of the foreign/self complex, thus enhancing an autoimmune response. Polyacrylamide gel electrophoresis (PAGE) revealed the presence of new peptides in pellets of supernatants of PMA-stimulated HIAP cells, with prominent bands at 55 and 43 kDa, and several fainter ones. HIAP infection was transferred by cell-free filtered supernatants from stimulated cells to H9 cells, which became identical to parent HIAP cells by PAGE and fluorescence activated cell sorter.