Long term aging of Selenide glasses: Evidence of sub-Tg endotherms and pre-Tg exotherms

Long term aging is studied on several families of chalcogenide glasses including the Ge-Se, As-Se, Ge-P-Se and Ge-As-Se systems. Special attention is given to the As-Se binary, a system that displays a rich variety of aging behavior intimately tied to sample synthesis conditions and the ambient environment in which samples are aged. Calorimetric (Modulated DSC) and Raman scattering experiments are undertaken. Our results show all samples display a sub-Tg endotherm below Tg in glassy networks possessing a mean coordination number r in the 2.25 < r < 2.45 range. Two sets of AsxSe1-x samples aged for 8 years were compared, set A consisted of slow cooled samples aged in the dark, and set B consisted of melt quenched samples aged at laboratory environment. Samples of set B in the As concentration range, 35% < x < 60%, display a pre-Tg exotherm, but the feature is not observed in samples of set A. The aging behavior of set A presumably represents intrinsic aging in these glasses, while that of set B is extrinsic due to presence of light. The reversibility window persists in both sets of samples but is less well defined in set B. These findings contrast with a recent study by Golovchak et al., which finds the onset of the reversibility window moved up to the stoichiometric composition (x = 40%). Here we show that the upshifted window is better understood as resulting due to demixing of As4Se4 and As4Se3 molecules from the backbone, i.e., Nanoscale phase separation (NSPS). We attribute sub-Tg endotherms to compaction of the flexible part of networks upon long term aging, while the pre-Tg exotherm to NSPS. Finally, the narrowing and sharpening of the reversibility window upon aging is interpreted as the slow 'self-organizing' stress relaxation of the phases just outside the Intermediate phase.Comment: In press - J. of Physics: Condensed Matte

Non-Human Primate Model of Kaposi's Sarcoma-Associated Herpesvirus Infection

Since Kaposi's sarcoma-associated herpesvirus (KSHV or human herpesvirus 8) was first identified in Kaposi's sarcoma (KS) lesions of HIV-infected individuals with AIDS, the basic biological understanding of KSHV has progressed remarkably. However, the absence of a proper animal model for KSHV continues to impede direct in vivo studies of viral replication, persistence, and pathogenesis. In response to this need for an animal model of KSHV infection, we have explored whether common marmosets can be experimentally infected with human KSHV. Here, we report the successful zoonotic transmission of KSHV into common marmosets (Callithrix jacchus, Cj), a New World primate. Marmosets infected with recombinant KSHV rapidly seroconverted and maintained a vigorous anti-KSHV antibody response. KSHV DNA and latent nuclear antigen (LANA) were readily detected in the peripheral blood mononuclear cells (PBMCs) and various tissues of infected marmosets. Remarkably, one orally infected marmoset developed a KS-like skin lesion with the characteristic infiltration of leukocytes by spindle cells positive for KSHV DNA and proteins. These results demonstrate that human KSHV infects common marmosets, establishes an efficient persistent infection, and occasionally leads to a KS-like skin lesion. This is the first animal model to significantly elaborate the important aspects of KSHV infection in humans and will aid in the future design of vaccines against KSHV and anti-viral therapies targeting KSHV coinfected tumor cells

Developing effective social media messages: Insights from an exploratory study of industry experts

As consumers are increasingly utilizing the social network and media platforms for prepurchase information, managers are confronted with producing effective social media messages that can favorably influence buyers’ attitudes and behavioral intentions towards brands. A qualitative, in‐depth, elite interview investigation with social media marketing experts was undertaken to develop awareness of the factors influencing the effectiveness of social media marketing. Adopting a thematic analysis approach, this study establishes the three overriding themes of interactivity, credibility, and infotainment as being valuable in determining how social media marketing can enhance brand performance. Attitude theory and the hierarchy‐of‐effects model is utilized to support understanding and explain the decision making of social media users in this context. Overall, this study provides managers with a thorough explanation of the effects of the identified core themes on social media attitudes and intentions. Implications for social media marketing theory and practice are presented based upon the depth and breadth of knowledge attained from the analysis of the expert interview data