Spatially-resolved electronic and vibronic properties of single diamondoid molecules

Diamondoids are a unique form of carbon nanostructure best described as hydrogen-terminated diamond molecules. Their diamond-cage structures and tetrahedral sp3 hybrid bonding create new possibilities for tuning electronic band gaps, optical properties, thermal transport, and mechanical strength at the nanoscale. The recently-discovered higher diamondoids (each containing more than three diamond cells) have thus generated much excitement in regards to their potential versatility as nanoscale devices. Despite this excitement, however, very little is known about the properties of isolated diamondoids on metal surfaces, a very relevant system for molecular electronics. Here we report the first molecular scale study of individual tetramantane diamondoids on Au(111) using scanning tunneling microscopy and spectroscopy. We find that both the diamondoid electronic structure and electron-vibrational coupling exhibit unique spatial distributions characterized by pronounced line nodes across the molecular surfaces. Ab-initio pseudopotential density functional calculations reveal that the observed dominant electronic and vibronic properties of diamondoids are determined by surface hydrogen terminations, a feature having important implications for designing diamondoid-based molecular devices.Comment: 16 pages, 4 figures. to appear in Nature Material

Case-based reported mortality associated with laboratory-confirmed influenza A(H1N1) 2009 virus infection in the Netherlands: the 2009-2010 pandemic season versus the 2010-2011 influenza season

<p>Abstract</p> <p>Background</p> <p>In contrast to seasonal influenza epidemics, where the majority of deaths occur amongst elderly, a considerable part of the 2009 pandemic influenza related deaths concerned relatively young people. In the Netherlands, all deaths associated with laboratory-confirmed influenza A(H1N1) 2009 virus infection had to be notified, both during the 2009-2010 pandemic season and the 2010-2011 influenza season. To assess whether and to what extent pandemic mortality patterns were reverting back to seasonal patterns, a retrospective analyses of all notified fatal cases associated with laboratory-confirmed influenza A(H1N1) 2009 virus infection was performed.</p> <p>Methods</p> <p>The notification database, including detailed information about the clinical characteristics of all notified deaths, was used to perform a comprehensive analysis of all deceased patients with a laboratory-confirmed influenza A(H1N1) 2009 virus infection. Characteristics of the fatalities with respect to age and underlying medical conditions were analysed, comparing the 2009-2010 pandemic and the 2010-2011 influenza season.</p> <p>Results</p> <p>A total of 65 fatalities with a laboratory-confirmed influenza A(H1N1) 2009 virus infection were notified in 2009-2010 and 38 in 2010-2011. During the pandemic season, the population mortality rates peaked in persons aged 0-15 and 55-64 years. In the 2010-2011 influenza season, peaks in mortality were seen in persons aged 0-15 and 75-84 years. During the 2010-2011 influenza season, the height of first peak was lower compared to that during the pandemic season. Underlying immunological disorders were more common in the pandemic season compared to the 2010-2011 season (p = 0.02), and cardiovascular disorders were more common in the 2010-2011 season (p = 0.005).</p> <p>Conclusions</p> <p>The mortality pattern in the 2010-2011 influenza season still resembled the 2009-2010 pandemic season with a peak in relatively young age groups, but concurrently a clear shift toward seasonal patterns was seen, with a peak in mortality in the elderly, i.e. ≥ 75 years of age.</p

Evaluation of Indirect Fluorescent Antibody Assays Compared to Rapid Influenza Diagnostic Tests for the Detection of Pandemic Influenza A (H1N1) pdm09

Performance of indirect fluorescent antibody (IFA) assays and rapid influenza diagnostic tests (RIDT) during the 2009 H1N1 pandemic was evaluated, along with the relative effects of age and illness severity on test accuracy. Clinicians and laboratories submitted specimens on patients with respiratory illness to public health from April to mid October 2009 for polymerase chain reaction (PCR) testing as part of pandemic H1N1 surveillance efforts in Orange County, CA; IFA and RIDT were performed in clinical settings. Sensitivity and specificity for detection of the 2009 pandemic H1N1 strain, now officially named influenza A(H1N1)pdm09, were calculated for 638 specimens. Overall, approximately 30% of IFA tests and RIDTs tested by PCR were falsely negative (sensitivity 71% and 69%, respectively). Sensitivity of RIDT ranged from 45% to 84% depending on severity and age of patients. In hospitalized children, sensitivity of IFA (75%) was similar to RIDT (84%). Specificity of tests performed on hospitalized children was 94% for IFA and 80% for RIDT. Overall sensitivity of RIDT in this study was comparable to previously published studies on pandemic H1N1 influenza and sensitivity of IFA was similar to what has been reported in children for seasonal influenza. Both diagnostic tests produced a high number of false negatives and should not be used to rule out influenza infection

Anticipatory governance for social-ecological resilience

Anticipation is increasingly central to urgent contemporary debates, from climate change to the global economic crisis. Anticipatory practices are coming to the forefront of political, organizational, and citizens’ society. Research into anticipation, however, has not kept pace with public demand for insights into anticipatory practices, their risks and uses. Where research exists, it is deeply fragmented. This paper seeks to identify how anticipation is defined and understood in the literature and to explore the role of anticipatory practice to address individual, social, and global challenges. We use a resilience lens to examine these questions. We illustrate how varying forms of anticipatory governance are enhanced by multi-scale regional networks and technologies and by the agency of individuals, drawing from an empirical case study on regional water governance of Malaren, Sweden. Finally, we discuss how an anticipatory approach can inform adaptive institutions, decision making, strategy formation, and societal resilience

Factors associated with death in hospitalized pneumonia patients with 2009 H1N1 influenza in Shenyang, China

<p>Abstract</p> <p>Background</p> <p>During the spring of 2009, a pandemic influenza A (H1N1) virus emerged and spread globally. We describe the clinical characteristics and factors associated with the death of patients who were hospitalized with 2009 H1N1 influenza pneumonia in Shenyang, China, from November to December 2009.</p> <p>Methods</p> <p>We carried out a retrospective chart review of 68 patients who were hospitalized with pneumonia and confirmed to have 2009 H1N1 virus infection by a real time RT-PCR assay of respiratory specimens.</p> <p>Results</p> <p>Of the 68 patients we studied, 30 (44%) were admitted to an intensive care unit and 10 (14.7%) died. The median age of patients was 41 years (range, 18-66), and only one patient was over 65 years of age. The male to female ratio was 2.78:1 (50:18). Of the 68 patients, 23 (34%) had at least one underlying medical condition, 9 (13%) had a cigarette index ≥400 and 22 (32%) were obese. All patients underwent chest radiography on admission and the findings were consistent with pneumonia in all cases. All patients were treated with oseltamivir and treatment was initiated at a median time of seven days after the onset of illness. The laboratory test results indicated lymphopenia, hypoproteinemia and elevated lactic dehydrogenase and C reactive protein levels. Of the 68 patients, 33 (52%) showed a reduction in CD4 T cell counts. Of the 58 patients who survived, 31 (53%) had lymphopenia and 27 recovered from this condition after five days. Of the 10 patients who died, nine (90%) had lymphopenia and only two patients recovered from this condition after five days. Obesity and recovery from lymphopenia after five days were factors associated with death, as determined by multivariate logistic-regression analysis (obesity, odds ratio = 23.06; lymphocytopenia reversion, odds ration = 28.69).</p> <p>Conclusions</p> <p>During the evaluation period in Shenyang, China, 2009 H1N1 influenza caused severe illness requiring hospitalization in 68 patients, 10 (14.7%) of which died. Many of these patients were considered healthy adults and few were elderly (65 years or older). Obesity and lymphopenia, which was not restored after five days of treatment, were factors associated with poor outcomes of 2009 H1N1 influenza infection.</p

Epidemiological and clinical characteristics of childhood pandemic 2009 H1N1 virus infection: an observational cohort study

<p>Abstract</p> <p>Background</p> <p>There was a pandemic influenza around the world in 2009 including South Korea since last pandemic occurred four decades ago. We aimed to evaluate the epidemiological and clinical characteristics of this infection in childhood.</p> <p>Methods</p> <p>We evaluated the epidemiologic characteristics of all the subjects infected with the 2009 H1N1 influenza A virus (2,971 patients, ≤ 15 years of age), and the clinical and laboratory findings of the inpatients (217 patients, 80 had pneumonia) between 1 September 2009 and 31 January 2010 in a single hospital throughout the epidemic.</p> <p>Results</p> <p>The age distribution of all the subjects was relatively even. Over 90% of cases occurred during a two-month period. Two hundred and five patients (94.5%) received oseltamivir within 48 h of fever onset, and 97% of inpatients defervesced within 48 h of medication. The group with pneumonia included more males than females, and had higher leukocytes counts with lower lymphocyte differentials than the group without pneumonia. The white blood cell count and lymphocyte differential were associated with the severity of pneumonia. Corticosteroid treatment for severe pneumonia patients was highly effective in preventing disease progression.</p> <p>Conclusion</p> <p>Children of all ages affected with even rates of infection, but males were predominant in pneumonia patients. Pneumonia patients showed lymphopenia and its severity was associated with the severity of illness. Our results suggest that the mechanism of lung injury in 2009 H1N1 virus infection may be associated with the host immune response.</p

Novel roles of the chemorepellent axon guidance molecule RGMa in cell migration and adhesion

The repulsive guidance molecule A (RGMa) is a contact-mediated axon guidance molecule that has significant roles in central nervous system (CNS) development. Here we have examined whether RGMa has novel roles in cell migration and cell adhesion outside the nervous system. RGMa was found to stimulate cell migration from Xenopus animal cap explants in a neogenin-dependent and BMP-independent manner. RGMa also stimulated the adhesion of Xenopus animal cap cells, and this adhesion was dependent on neogenin and independent of calcium. To begin to functionally characterize the role of specific domains in RGMa, we assessed the migratory and adhesive activities of deletion mutants. RGMa lacking the partial von Willebrand factor type D (vWF) domain preferentially perturbed cell adhesion, while mutants lacking the RGD motif affected cell migration. We also revealed that manipulating the levels of RGMa in vivo caused major migration defects during Xenopus gastrulation. We have revealed here novel roles of RGMa in cell migration and adhesion and demonstrated that perturbations to the homeostasis of RGMa expression can severely disrupt major morphogenetic events. These results have implications for understanding the role of RGMa in both health and disease

Effect of D222G Mutation in the Hemagglutinin Protein on Receptor Binding, Pathogenesis and Transmissibility of the 2009 Pandemic H1N1 Influenza Virus

Influenza viruses isolated during the 2009 H1N1 pandemic generally lack known molecular determinants of virulence associated with previous pandemic and highly pathogenic avian influenza viruses. The frequency of the amino acid substitution D222G in the hemagglutinin (HA) of 2009 H1N1 viruses isolated from severe but not mild human cases represents the first molecular marker associated with enhanced disease. To assess the relative contribution of this substitution in virus pathogenesis, transmission, and tropism, we introduced D222G by reverse genetics in the wild-type HA of the 2009 H1N1 virus, A/California/04/09 (CA/04). A dose-dependent glycan array analysis with the D222G virus showed a modest reduction in the binding avidity to human-like (α2-6 sialylated glycan) receptors and an increase in the binding to avian-like (α2-3 sialylated glycan) receptors in comparison with wild-type virus. In the ferret pathogenesis model, the D222G mutant virus was found to be similar to wild-type CA/04 virus with respect to lethargy, weight loss and replication efficiency in the upper and lower respiratory tract. Moreover, based on viral detection, the respiratory droplet transmission properties of these two viruses were found to be similar. The D222G virus failed to productively infect mice inoculated by the ocular route, but exhibited greater viral replication and weight loss than wild-type CA/04 virus in mice inoculated by the intranasal route. In a more relevant human cell model, D222G virus replicated with delayed kinetics compared with wild-type virus but to higher titer in human bronchial epithelial cells. These findings suggest that although the D222G mutation does not influence virus transmission, it may be considered a molecular marker for enhanced replication in certain cell types.Centers for Disease Control and Prevention (U.S.)United States. National Institutes of Health (merit award R37 GM057073-13)Singapore-MIT Alliance for Research and Technolog

Variations in the Hemagglutinin of the 2009 H1N1 Pandemic Virus: Potential for Strains with Altered Virulence Phenotype?

A novel, swine-origin influenza H1N1 virus (H1N1pdm) caused the first pandemic of the 21st century. This pandemic, although efficient in transmission, is mild in virulence. This atypical mild pandemic season has raised concerns regarding the potential of this virus to acquire additional virulence markers either through further adaptation or possibly by immune pressure in the human host. Using the mouse model we generated, within a single round of infection with A/California/04/09/H1N1 (Ca/04), a virus lethal in mice—herein referred to as mouse-adapted Ca/04 (ma-Ca/04). Five amino acid substitutions were found in the genome of ma-Ca/04: 3 in HA (D131E, S186P and A198E), 1 in PA (E298K) and 1 in NP (D101G). Reverse genetics analyses of these mutations indicate that all five mutations from ma-Ca/04 contributed to the lethal phenotype; however, the D131E and S186P mutations—which are also found in the 1918 and seasonal H1N1 viruses—in HA alone were sufficient to confer virulence of Ca/04 in mice. HI assays against H1N1pdm demonstrate that the D131E and S186P mutations caused minor antigenic changes and, likely, affected receptor binding. The rapid selection of ma-Ca/04 in mice suggests that a virus containing this constellation of amino acids might have already been present in Ca/04, likely as minor quasispecies