The effect of normative social influence and cultural diversity on group interactions

Motivated by concerns regarding the impact of cultural diversity on group interaction processes and a desire to extend the Social Influence Model of Technology Use, this paper discusses the impact of normative social influence on enhancing group media use and group decision making performance over time in different cultural group compositions. This paper proposes that the strength of attraction to the group influences the similarity in media perception and use of group members. The similarity of group media perception and use is proposed to influence group performance. Concurrently, group cohesion, similarity of media perception and use, and group performance are positively correlated over time. Since culture affects individuals' values, beliefs and behavior, this paper proposes that the degree of similarity in media perception and media use may differ when group composition varies by culture. Several propositions for empirical examination are highlighted. Finally, the paper concludes with a discussion of the importance and implications of understanding cultural diversity and social influence on technology use and group performance. © 2006 IEEE

Messaging media perceptions and preferences: a pilot study in two distinct cultures

This study empirically examines university students' perceptions and their views of when they adopt Instant Messaging (IM) and Short Messaging Service (SMS) and how they perceive and prefer these two media, in conjunction with other media (face-to-face, telephone, and email), in their university learning activities across two different cultural contexts: Australian university and Chinese university. The overall results of this study support some aspects of media richness theory. Although IM is perceived to be richer than email, it is not perceived to be the most popular medium for any situation. Data also demonstrate cultural differences in media perceptions of and preferences for new media. Specifically, Australian students have higher preference for email than their Chinese counterparts and Australian students also perceive SMS as leaner in terms of medium richness and have less preference for SMS than their Chinese counterparts. © 2007 IEEE

Zika Virus Attenuation by Codon Pair Deoptimization Induces Sterilizing Immunity in Mouse Models.

Zika virus (ZIKV) infection during the large epidemics in the Americas is related to congenital abnormities or fetal demise. To date, there is no vaccine, antiviral drug, or other modality available to prevent or treat Zika virus infection. Here we designed novel live attenuated ZIKV vaccine candidates using a codon pair deoptimization strategy. Three codon pair-deoptimized ZIKVs (Min E, Min NS1, and Min E+NS1) were de novo synthesized and recovered by reverse genetics and contained large amounts of underrepresented codon pairs in the E gene and/or NS1 gene. The amino acid sequence was 100% unchanged. The codon pair-deoptimized variants had decreased replication fitness in Vero cells (Min NS1 ≫ Min E > Min E+NS1), replicated more efficiently in insect cells than in mammalian cells, and demonstrated diminished virulence in a mouse model. In particular, Min E+NS1, the most restrictive variant, induced sterilizing immunity with a robust neutralizing antibody titer, and a single immunization achieved complete protection against lethal challenge and vertical ZIKV transmission during pregnancy. More importantly, due to the numerous synonymous substitutions in the codon pair-deoptimized strains, reversion to wild-type virulence through gradual nucleotide sequence mutations is unlikely. Our results collectively demonstrate that ZIKV can be effectively attenuated by codon pair deoptimization, highlighting the potential of Min E+NS1 as a safe vaccine candidate to prevent ZIKV infections.IMPORTANCE Due to unprecedented epidemics of Zika virus (ZIKV) across the Americas and the unexpected clinical symptoms, including Guillain-Barré syndrome, microcephaly, and other birth defects in humans, there is an urgent need for ZIKV vaccine development. Here we provided the first attenuated versions of ZIKV with two important genes (E and/or NS1) that were subjected to codon pair deoptimization. Compared to parental ZIKV, the codon pair-deoptimized ZIKVs were mammal attenuated and preferred insect to mammalian cells. Min E+NS1, the most restrictive variant, induced sterilizing immunity with a robust neutralizing antibody titer and achieved complete protection against lethal challenge and vertical virus transmission during pregnancy. More importantly, the massive synonymous mutational approach made it impossible for the variant to revert to wild-type virulence. Our results have proven the feasibility of codon pair deoptimization as a strategy to develop live attenuated vaccine candidates against flaviviruses such as ZIKV, Japanese encephalitis virus, and West Nile virus

In vivo imaging of Zika virus reveals dynamics of viral invasion in immune-sheltered tissues and vertical propagation during pregnancy

Rationale: Zika virus (ZIKV) is a pathogenic virus known to cause a wide range of congenital abnormalities, including microcephaly, Guillain-Barre syndrome, meningoencephalitis, and other neurological complications, in humans. This study investigated the noninvasive detection of ZIKV infection in vivo, which is necessary for elucidating the virus's mechanisms of viral replication and pathogenesis, as well as to accelerate the development of anti-ZIKV therapeutic strategies. Methods: In this study, a recombinant ZIKV harbouring Nluc gene (ZIKV-Nluc) was designed, recovered, and purified. The levels of bioluminescence were directly correlated with viral loads in vitro and in vivo. The dynamics of ZIKV infection in A129 (interferon (IFN)-α/β receptor deficient), AG6 (IFN-α/β and IFN-γ receptor deficient), and C57BL/6 mice were characterized. Pregnant dams were infected with ZIKV-Nluc at E10 via intra footpad injection. Then, the pooled immune sera (anti-ZIKV neutralizing antibodies) #22-1 in ZIKV-Nluc virus-infected mice were visualized. Results: ZIKV-Nluc showed a high genetic stability and replicated well in cells with similar properties to the wild-type ZIKV (ZIKVwt). Striking bioluminescence signals were consistently observed in animal organs, including spleen, intestine, testis, uterus/ovary, and kidney. The ileocecal junction was found to be the crucial visceral target. Infection of pregnant dams with ZIKV-Nluc showed that ZIKV was capable of crossing the maternal-fetal barrier to infect the fetuses via vertical transmission. Furthermore, it was visualized that treatment with the pooled immune sera was found to greatly restrict the spread of the ZIKV-Nluc virus in mice. Conclusions: This study is the first to report the real-time noninvasive tracking of the progression of ZIKV invading immune-sheltered tissues and propagating vertically during pregnancy. The results demonstrate that ZIKV-Nluc represents a powerful tool for the study of the replication, dissemination, pathogenesis, and treatment of ZIKV in vitro and in vivo

Observation of in-gap surface states in the Kondo insulator SmB6 by photoemission

Kondo insulators (KIs) are strongly correlated materials in which the interactions between 4f and conduction electrons lead to a hybridization gap opening at low temperature 1-2. SmB6 is a typical KI, but its resistivity does not diverge at low temperatures, which was attributed to some in-gap states 3-10. However after several decades of research, the nature and origin of the in-gap states remain unclear. Recent band calculation and transport measurements suggest that the in-gap states could actually be ascribed to topological surface states. SmB6 thus might be the first realization of topological Kondo insulator (TKI) 13, the strongly correlated version of topological insulator (TI) 11,12. Here by performing angle-resolved photoemission spectroscopy (ARPES), we directly observed several dispersive states within the hybridization gap of SmB6, which cross the Fermi level and show negligible kz dependence, indicative of their surface origin. Furthermore, the circular dichroism (CD) ARPES results of the in-gap states suggest the chirality of orbital momentum, and temperature dependent measurements have shown that the in-gap states vanish simultaneously with the hybridization gap around 150 K. These strongly suggest their possible topological origin.Comment: 18 pages, 8 figure

Dynamic shear fracture toughness and failure characteristics of Ti–6Al–4V alloy under high loading rates

A novel 2-bar/double-shear impact (2B/2SI) loading technique is used to study the dynamic mode II (shear) fracture characteristics of Ti–6Al–4V. The new specimen design, to be used in combination with a standard split Hopkinson pressure bar, circumvent classical limitations associated with conventional one-point impact methods. This paper presents a combined experimental-numerical approach to determining the mode II fracture toughness of Ti–6Al–4V for a broad range of loading rates between 1.10 × 10^{−2}- 4.98 × 10^{7} (MPa, m^{1/2}s^{−1}). Results showed only a slight initial increase in toughness, which increases abruptly with loading rates beyond 10^{6} (MPa, m^{1/2}s^{−1}). Fractographic examination showed distinctively different mechanisms in operation at the microscale, depending on the rate of loading. Failure is through a brittle-ductile, mixed-mode fracture under quasi-static conditions; by contrast, the fracture surface exhibited fractographic features of adiabatic shear bands (ASB) and material melting/re-solidification under dynamic conditions. High-speed photography showed that both dynamic shear fracture (DSF) and ASB occurred during the same loading process. Interactions between DSF and ASB were observed to influence the dominant failure mechanism of the material at high loading rates