Crystal growth, characterization and electronic band structure of TiSeS

Layered semimetallic van der Waals materials TiSe2 has attracted a lot of attention because of interplay of a charge density wave (CDW) state and superconductivity. Its sister compound TiS2, being isovalent to TiSe2 and having the same crystal structure, shows a semiconducting behavior. The natural rises what happens at the transition point in TiSe2-xSx, which is expected for x close to 1. Here we report the growth and characterization of TiSeS single crystals and the study of the electronic structure using density functional theory (DFT) and angle-resolved photoemission (ARPES). We show that TiSeS single crystals have the same morphology as TiSe2. Transport measurements reveal a metallic state, no evidence of CDW was found. DFT calculations suggest that the electronic band structure in TiSeS is similar to that of TiSe2, but the electron and hole pockets in TiSeS are much smaller. The ARPES results are in good agreement with the calculations.Comment: 22 pages, 9 figure

Fermi surface tomography

Fermi surfaces are essential for predicting, characterizing and controlling the properties of crystalline metals and semiconductors. Angle-resolved photoemission spectroscopy (ARPES) is the only technique directly probing the Fermi surface by measuring the Fermi momenta (k(F)) from energy- and angular distribution of photoelectrons dislodged by monochromatic light. Existing apparatus is able to determine a number of k(F) -vectors simultaneously, but direct high-resolution 3D Fermi surface mapping remains problematic. As a result, no such datasets exist, strongly limiting our knowledge about the Fermi surfaces. Here we show that using a simpler instrumentation it is possible to perform 3D-mapping within a very short time interval and with very high resolution. We present the first detailed experimental 3D Fermi surface as well as other experimental results featuring advantages of our technique. In combination with various light sources our methodology and instrumentation offer new opportunities for high-resolution ARPES in the physical and life sciences

Serum eosinophil cationic protein in children with atopic dermatitis

BACKGROUND: Eosinophil cationic protein (ECP) is a cytotoxic agent secreted by activated eosinophils during allergic and inflammatory processes. The aim of the study was to determine the ECP level, absolute and relative eosinophil count and IgE antibodies in children with atopic dermatitis (AD) compared with those of nonatopic children, and to assess the correlation of these laboratory parameters with the clinical severity of AD. ----- METHODS: This prospective study comprised 70 children. There were 49 children with AD aged 3-36 months, and the control group comprised 21 children with a negative personal and family history for atopic diseases. Detailed history, serum ECP levels (UniCAP FEIA), relative and absolute eosinophil counts and total serum IgE antibodies were determined in both groups. In the children with AD, skin involvement was measured by the SCORAD index. ----- RESULTS: The calculated SCORAD index was between 16 and 83. IgE antibodies, relative and absolute eosinophil counts showed a significantly wider range of values and a statistically higher median (P 0.05). The same was found for the correlation of serum ECP and intensity of skin changes (r = -0.095) and serum ECP and subjective symptoms (r = -0.045). The correlation was positive, but weak and statistically not significant for the serum ECP and extent of the skin lesions (r = 0.079, P > 0.05). ----- CONCLUSION: Elevated levels of ECP, relative and absolute eosinophil counts, as well as IgE antibodies were determined in the patients with AD. As these laboratory findings did not correlate with the severity of AD, they can be considered only as additional methods in the evaluation of patients with AD

Elevated serum substance P during simian varicella virus infection in rhesus macaques: implications for chronic inflammation and adverse cerebrovascular events

Varicella and zoster, produced by varicella zoster virus (VZV), are associated with an increased risk of stroke that may be due to persistent inflammation and hypercoagulability. Because substance P is associated with inflammation, hypercoagulability, and atherosclerotic plaque rupture that may contribute to increased stroke risk after VZV infection, we measured serum substance P in simian varicella virus-infected rhesus macaques. We found significantly increased and persistent serum substance P concentrations during varicella and zoster compared to pre-inoculation, supporting the hypothesis that VZV-induced increases in serum substance P may contribute to increased stroke risk associated with VZV infection

Histopathological Analysis of Adrenal Glands after Simian Varicella Virus Infection

Latent varicella zoster virus (VZV) has been detected in human adrenal glands, raising the possibility of virus-induced adrenal damage and dysfunction during primary infection or reactivation. Rare cases of bilateral adrenal hemorrhage and insufficiency associated with VZV reactivation have been reported. Since there is no animal model for VZV infection of adrenal glands, we obtained adrenal glands from two non-human primates (NHPs) that spontaneously developed varicella from primary simian varicella virus (SVV) infection, the NHP VZV homolog. Histological and immunohistochemical analysis revealed SVV antigen and DNA in the adrenal medulla and cortex of both animals. Adrenal glands were observed to have Cowdry A inclusion bodies, cellular necrosis, multiple areas of hemorrhage, and varying amounts of polymorphonuclear cells. No specific association of SVV antigen with βIII-tubulin-positive nerve fibers was found. Overall, we found that SVV can productively infect NHP adrenal glands, and is associated with inflammation, hemorrhage, and cell death. These findings suggest that further studies are warranted to examine the contribution of VZV infection to human adrenal disease. This study also suggests that VZV infection may present itself as acute adrenal dysfunction with “long-hauler” symptoms of fatigue, weakness, myalgias/arthralgias, and hypotension

Simian Varicella Virus Pathogenesis in Skin during Varicella and Zoster

Primary simian varicella virus (SVV) infection and reactivation in nonhuman primates is a valuable animal model in the study of varicella zoster virus disease [varicella (chickenpox) and herpes zoster (shingles)]. To understand SVV pathogenesis in skin, we inoculated 10 rhesus macaques with SVV, resulting in varicella rash. After the establishment of latency, eight of the monkeys were immunosuppressed using tacrolimus with or without irradiation and prednisone and two monkeys were not immunosuppressed. Zoster rash developed in all immunosuppressed monkeys and in one non-immunosuppressed monkey. Five monkeys had recurrent zoster. During varicella and zoster, SVV DNA in skin scrapings ranged from 50 to 10 copies/100 ng of total DNA and 2-127 copies/100 ng of total DNA, respectively. Detection of SVV DNA in blood during varicella was more frequent and abundant compared to that of zoster. During varicella and zoster, SVV antigens colocalized with neurons expressing β-III tubulin in epidermis, hair follicles, and sweat glands, suggesting axonal transport of the virus. Together, we have demonstrated that both SVV DNA and antigens can be detected in skin lesions during varicella and zoster, providing the basis for further studies on SVV skin pathogenesis, including immune responses and mechanisms of peripheral spread