Million Atom Electronic Structure and Device Calculations on Peta-Scale Computers

Semiconductor devices are scaled down to the level which constituent materials are no longer considered continuous. To account for atomistic randomness, surface effects and quantum mechanical effects, an atomistic modeling approach needs to be pursued. The Nanoelectronic Modeling Tool (NEMO 3-D) has satisfied the requirement by including emprical $sp^{3}s^{*}$ and $sp^{3}d^{5}s^{*}$ tight binding models and considering strain to successfully simulate various semiconductor material systems. Computationally, however, NEMO 3-D needs significant improvements to utilize increasing supply of processors. This paper introduces the new modeling tool, OMEN 3-D, and discusses the major computational improvements, the 3-D domain decomposition and the multi-level parallelism. As a featured application, a full 3-D parallelized Schr\"odinger-Poisson solver and its application to calculate the bandstructure of $\delta$ doped phosphorus(P) layer in silicon is demonstrated. Impurity bands due to the donor ion potentials are computed.Comment: 4 pages, 6 figures, IEEE proceedings of the 13th International Workshop on Computational Electronics, Tsinghua University, Beijing, May 27-29 200

Insulin-like growth factors and related proteins in plasma and cerebrospinal fluids of HIV-positive individuals.

BackgroundClinically significant dysregulation of the insulin-like growth factor (IGF) family proteins occurs in HIV-infected individuals, but the details including whether the deficiencies in IGFs contribute to CNS dysfunction are unknown.MethodsWe measured the levels of IGF1, IGF2, IGFBP1, IGFBP2, and IGF2 receptor (IGF2R) in matching plasma and cerebrospinal fluid (CSF) samples of 107 HIV+ individuals from CNS HIV Antiretroviral Therapy Effects Research (CHARTER) and analyzed their associations with demographic and disease characteristics, as well as levels of several soluble inflammatory mediators (TNFα, IL-6, IL-10, IL-17, IP-10, MCP-1, and progranulin). We also determined whether IGF1 or IGF2 deficiency is associated with HIV-associated neurocognitive disorder (HAND) and whether the levels of soluble IGF2R (an IGF scavenging receptor, which we also have found to be a cofactor for HIV infection in vitro) correlate with HIV viral load (VL).ResultsThere was a positive correlation between the levels of IGF-binding proteins (IGFBPs) and those of inflammatory mediators: between plasma IGFBP1 and IL-17 (β coefficient 0.28, P = 0.009), plasma IGFBP2 and IL-6 (β coefficient 0.209, P = 0.021), CSF IGFBP1 and TNFα (β coefficient 0.394, P < 0.001), and CSF IGFBP2 and TNF-α (β coefficient 0.14, P < 0.001). As IGFBPs limit IGF availability, these results suggest that inflammation is a significant factor that modulates IGF protein expression/availability in the setting of HIV infection. However, there was no significant association between HAND and the reduced levels of plasma IGF1, IGF2, or CSF IGF1, suggesting a limited power of our study. Interestingly, plasma IGF1 was significantly reduced in subjects on non-nucleoside reverse transcriptase inhibitor-based antiretroviral therapy (ART) compared to protease inhibitor-based therapy (174.1 ± 59.8 vs. 202.8 ± 47.3 ng/ml, P = 0.008), suggesting a scenario in which ART regimen-related toxicity can contribute to HAND. Plasma IGF2R levels were positively correlated with plasma VL (β coefficient 0.37, P = 0.021) and inversely correlated with current CD4+ T cell counts (β coefficient -0.04, P = 0.021), supporting our previous findings in vitro.ConclusionsTogether, these results strongly implicate (1) an inverse relationship between inflammation and IGF growth factor availability and the contribution of IGF deficiencies to HAND and (2) the role of IGF2R in HIV infection and as a surrogate biomarker for HIV VL

A Study of Temperature-dependent Properties of N-type delta-doped Si Band-structures in Equilibrium

A highly phosphrous delta-doped Si device is modeled with a quantum well with periodic boundary conditions and the semi-empirical spds* tight-binding band model. Its temperature-dependent electronic properties are studied. To account for high doping density with many electrons, a highly parallelized self-consistent Schroedinger-Poisson solver is used with atomistic representations of multiple impurity ions. The band-structure in equilibrium and the corresponding Fermi-level position are computed for a selective set of temperatures. The result at room temperature is compared with previous studies and the temperature-dependent electronic properties are discussed further in detail with the calculated 3-D self-consistent potential profile.Comment: IEEE proceedings of the 13th International Workshop on Computational Electronics (IWCE-13

A study of the time-averaged paleomagnetic field for the last 195 million years

During the last decade a great deal of paleomagnetic results have accumulated, and their accuracy and reliability have been increased significantly by improved demagnetisation techniques. In the present thesis all available paleomagnetic data have been analysed for the purposes of providing more understanding of characteristics of the geomagnetic field through geological time. Also, physical implications for geodynamo theory have been sought! As preparatory procedures, data selection, the separation of data according to polarity, and correction for plate tectonics effects have been carried out. With such selected (and corrected) paleomagnetic data, spherical harmonic analyses and statistical analyses of the paleosecular variatioll have been carried out for the time-averaged paleomagnetic field from Recent back to 195 Myr ago. The results of these analyses have been compared with the reversal frequency characteristics of the paleomagnetic field. Thefollowing conclusions have been drawn from the analyses: (1) During time intervals for which the reversal frequency characteristic is stable, the normal and reversed polarity fields can be taken to be the same in terms of time-averaged Gauss coefficients. However, during time intervals for which the reversal frequency characteristic is unstable, the two polarity fields· can be taken to be different from each other. (2) The zonal quadrupole and octapole field components reverse together with the axial dipole component when the field reverses its polarity. (3) The zonal octapole component has been dominant (up to a maximum strength of order G3=0.16) relative to the quadrupole component (maximum strength of order G2=0.11) through time, regardless of polarity. ( 4) The variations with time of the time-averaged Gauss coefficients for the normal polarity field have similar patterns to the variations with time of those for the reversed polarity field. (5) When the reversal frequency is low, the paleosecular variation is relatively small and is found to be mainly due to changes in the nondipole field. However, when the reversal frequency is high, the paleosecular variation is relatively large, and is found to be mainly due to dipole wobble. (6) The variations with time of the paleosecular variation characteristics for the normal polarity field have similar patterns to the variations with time of those for the reversed polarity field. These results provide some important implications which any satisfactory geodynamo model should meet

Language learners retrieval strategies as shown in topic-controlled deletion in topic chains: A comparison between Chinese and Korean native speakers interlanguages

In Chinese, a topic-prominent language, pronouns are often omitted in favor of zero-anaphora. Therefore, Chinese-learners who are speakers of subject-prominent languages, like English, often repeat clause-initial pro-forms when speaking Chinese. However, it is unclear how the speakers of topic-prominent languages, such as Korean and Chinese, acquire zero-anaphora of second language. We investigated whether Korean- and Chinese-speakers naturally delete pro-forms when learning each others language and analyzing their writing and speaking. If positive transfer occurs when they acquire topic-related deletion, then written and spoken deletion should be similar. However, zero-anaphora emerging differently between written and spoken words must be a result of various cognitive strategies not affected by positive transfer. We observed 20 Korean- and 12 Chinese-learners for six months. All Chinese- and Korean-learners could delete topic-related pronouns in written text. Unlike English-speaking Chinese-learners, deletion occurred by positive transfer among Chinese-speaking Korean-learners and vice versa. Further, although the written task preceded the oral task, the participants deleted more pronouns in the written task. We think that learners switch codes using different strategies while writing and speaking. A psychological mechanism, not grammatical knowledge, plays a role: learners repeat pronouns to buy time to improve their discourse, in a so-called recharging strategy

Interferon regulatory factor 3 plays an anti-inflammatory role in microglia by activating the PI3K/Akt pathway

<p>Abstract</p> <p>Background</p> <p>Microglia are the principal cells involved in the innate immune response in the CNS. Activated microglia produce a number of proinflammatory cytokines implicated in neurotoxicity but they also are a major source of anti-inflammatory cytokines, antiviral proteins and growth factors. Therefore, an immune therapy aiming at suppressing the proinflammatory phenotype while enhancing the anti-inflammatory, growth promoting phenotype would be of great benefit. In the current study, we tested the hypothesis that interferon regulatory factor 3 (IRF3), a transcription factor required for the induction of IFNβ following TLR3 or TLR4 activation, is critical to the microglial phenotype change from proinflammatory to anti-inflammatory, and that this phenotype change can be greatly facilitated by IRF3 gene transfer.</p> <p>Methods</p> <p>Cultures of primary human fetal microglia were transduced with IRF3 using recombinant adenovirus (Ad-IRF3) and subjected to microarray analysis, real-time PCR, immunoblotting and ELISA to determine inflammatory gene expression. Two different types of immune stimuli were tested, the TLR ligands, poly IC (PIC) and LPS, and the proinflammatory cytokines, IL-1/IFNγ. In addition, the role of the PI3K/Akt pathway was examined by use of a pharmacological inhibitor, LY294002.</p> <p>Results</p> <p>Our results show that Ad-IRF3 suppressed proinflammatory genes (IL-1α, IL-1β, TNFα, IL-6, IL-8 and CXCL1) and enhanced anti-inflammatory genes (IL-1 receptor antagonist, IL-10 and IFNβ) in microglia, regardless of the cell stimuli applied. Furthermore, Ad-IRF3 activated Akt, and LY294002 reversed the effects of Ad-IRF3 on microglial inflammatory gene expression. pAkt was critical in LPS- or PIC-induced production of IL-10 and IL-1ra. Significantly, microglial IFNβ protein production was also dependent on pAkt and required both Ad-IRF3 and immunological stimuli (PIC > IL-1/IFNγ). pAkt played much less prominent and variable roles in microglial proinflammatory gene expression. This anti-inflammatory promoting role of PI3K/Akt appeared to be specific to microglia, since astrocyte proinflammatory gene expression (as well as IFNβ expression) required PI3K/Akt.</p> <p>Conclusions</p> <p>Our results show a novel anti-inflammatory role for the PI3K/Akt signaling pathway in microglia. They further suggest that IRF3 gene therapy could facilitate the microglial phenotype switch from proinflammatory ("M1-like") to anti-inflammatory and immunomodulatory ("M2-like"), in part, by augmenting the level of pAkt.</p

A study of social sustainability practice in fashion accessories industry: Investigation of current practice and recommendations for future practice

Although there are a number of existing researches conducted regarding sustainability practice in fashion industry, it has been mostly limited to clothing industry within a broader concept with lack of empirical basis. This paper explores fashion accessories industry which has lack of exiting researches. The current study aims to discover in depth the current practice of social sustainability in fashion accessories providing the root causes of shortcomings of current sustainability. The paper reveals the disparities of definition and implication of sustainability for different stakeholders, which is underpinning idea that the current study goes further to suggest avenues for future research. This paper attempts to advance of understanding of practicing sustainability from practical viewpoints linking with existing theories from earlier scholars have released

Immunogenicity and protection conferred by a recombinant Mycobacterium marinum vaccine against Buruli ulcer

AbstractMycobacterium ulcerans (MU) infection causes the disfiguring necrotic skin disease, Buruli ulcer (BU). While vaccination with Mycobacterium bovis BCG provides nominal antigenic cross-reactivity for induction of immunity against experimental MU infection, a mycobacterial species with greater genetic homology to Mycobacterium ulcerans may serve as a richer source of cross-protective immunogens and lack the pathological features of MU-based vaccines. Mycobacterium marinum, a highly homologous genetic relative of MU, could be used to satisfy these criteria and, as such, we have generated a recombinant M. marinum strain expressing the immunodominant, protective MU-Ag85A. The immunogenicity and protection achieved by murine vaccination with this strain are superior to standard BCG vaccination and may serve as a foundation for developing more effective BU vaccines