Knowledge discovery from mining the association between H5N1 outbreaks and environmental factors

The global spread of highly pathogenic avian influenza H5N1 in poultry, wild birds and humans, poses a significant panzootic threat and a serious public health risk. An efficient surveillance and disease control system requires a deep understanding of their spread mechanisms, including environmental factors responsible for the outbreak of the disease. Previous studies suggested that H5N1 viruses occurred under specific environmental circumstances in Asia and Africa. These studies were mainly derived from poultry outbreaks. In Europe, a large number of wild bird outbreaks were reported in west Europe with few or no poultry infections nearby. This distinct outbreak pattern in relation to environmental characteristics, however, has not yet been explored. This research demonstrated the use of logistic regression analyses to examine quantitative associations between anthropogenic and physical environmental factors, and the wild bird H5N1outbreaks in Europe. A geographic information system is used to visualize and analyze the data. Our results indicate that the H5N1 outbreaks occur in wild birds in Europe under predictable environmental conditions, which are highly correlated with increased NDVI in December, decreased aspect and slope, increased minimum temperature in October and decreased precipitation in January. It suggests that H5N1 outbreaks in wild birds are strongly influenced by food resource availability and facilitated by the increased temperature and the decreased precipitation. We therefore deduce that the H5N1 outbreaks in wild birds in Europe may be mainly caused by contact with wild birds. These findings are of great importance for global surveillance of H5N1 outbreaks in wild birds

Environmental factors influencing the spread of the highly pathogenic avian influenza H5N1 virus in wild birds in Europe

A large number of occurrences of the highly pathogenic avian influenza (HPAI) H5N1 virus in wild birds were reported in Europe. The relationship between the occurrence pattern and environmental factors has, however, not yet been explored. This research uses logistic regression to quantify the relationships between anthropogenic or physical environmental factors and HPAI H5N1 occurrences. Our results indicate that HPAI H5N1 occurrences are highly correlated with the following: the increased normalized difference vegetation index (NDVI) in December; intermediate NDVI in March; lower elevations; increased minimum temperatures in January; and reduced precipitation in January. A predictive risk map of HPAI H5N1 occurrences in wild birds in Europe was generated on the basis of five key environmental factors. Independent validation of the risk map showed the predictive model to be of high accuracy (79%). The analysis suggests that HPAI H5N1 occurrences in wild birds are strongly influenced by the availability of food resources and are facilitated by increased temperatures and reduced precipitation. We therefore deduced that HPAI H5N1 occurrences in wild birds in Europe are probably caused by contact with other wild birds and not by contact with domestic poultry. These findings are important considerations for the global surveillance of HPAI H5N1 occurrences in wild birds

Mechanism of the Direct Hydrodenitrogenation of Naphthylamine on Sulfided NiMo/Al2O3

The hydrodenitrogenation of 1-naphthylamine was studied over a sulfided NiMo/Al2O3 catalyst between 300 and 350 °C. 1-Naphthylamine reacted to tetralin, naphthalene, 1,2-dihydronaphthalene and 5,6,7,8-tetrahydro-1-naphthylamine. To elucidate the reaction mechanism, the reactions of the intermediates 1,2,3,4-tetrahydro-1-naphthylamine, 1,2-dihydronaphthalene and 5,6,7,8-tetrahydro-1-naphthylamine were studied as well. The results show that 1-naphthylamine reacts through hydrogenation to 1,2,3,4-tetrahydro-1-naphthylamine, which reacts by NH3 elimination to 1,2-dihydronaphthalene. The latter molecule subsequently reacts by hydrogenation to tetralin as well as by dehydrogenation to naphthalene. In addition, naphthalene is formed by direct denitrogenation from 1-naphthylamine. This direct denitrogenation may take place by hydrogenation of 1-naphthylamine to 1,2-dihydro-1-naphthylamine, followed by NH3 elimination or followed by a Bucherer-type NH2-SH exchange, dehydrogenation and C-S bond hydrogenolysi

Will the Three Gorges Dam affect the underwater light climate of Vallisneria spiralis L. and food habitat of Siberian crane in Poyang Lake?

Almost 95% of the entire population of the Siberian crane (Grus leucogeranus) winter in Poyang Lake, China, where they forage on the tubers of the submerged aquatic macrophyte Vallisneria spiralis. The Three Gorges Dam on the Yangtze River may possibly affect this food source of the Siberian crane by affecting the light intensity reaching the top of the V. spiralis canopy. In this study, the photosynthetically active radiation at the top of the V. spiralis canopy (PARtc) in Lake Dahuchi was modeled from 1998 to 2006, and the potential impacts of changes in water level and turbidity on the underwater light climate of V. spiralis were analyzed. PARtc was calculated from incident irradiance while the losses due to reflection at the water surface, absorption, and scattering within the water column were taken into consideration. The results indicated significant differences in PARtc between years. Six years of water level and Secchi disk depth records revealed a seasonal switching of the lake from a turbid state at low water levels in autumn, winter, and spring to a clear state at high water levels during the monsoon in summer. The highest PARtc occurred at intermediate water levels, which were reached when the Yangtze River forces Lake Dahuchi out of its turbid state in early summer and the water becomes clear. The intended operation of the Three Gorges Dam, which will increase water levels in May and June, may advance the moment when Lake Dahuchi switches from turbid to clear. We suggest that this might increase production of V. spiralis and possibly improve the food habitat conditions for wintering Siberian crane in Poyang Lake

Mechanism of the hydrodenitrogenation of neopentylamine and adamantylamine on sulfided NiMo/Al2O3

Neopentanethiol, 1-adamantanethiol, and 2-adamantanethiol were primary products and neopentane and adamantane were secondary products in the hydrodenitrogenation of neopentylamine, 1-adamantylamine, and 2-adamantylamine, respectively, over sulfided NiMo/Al2O3. Dialkylamines and dialkylimines were formed as primary products in the reactions of 2-adamantylamine and neopentylamine as well. None of the three amines can react by ammonia elimination and a classic SN2 substitution of the NH2 group by H2S is not possible for the adamantylamines either. The formation of di(2-adamantyl)imine and di(neopentyl)imine indicates that dehydrogenation and hydrogenation reactions occur and that imine or iminium-cation intermediates play an important role. NH2-SH substitution takes place by dehydrogenation of the amine to an imine or iminium cation, which adds H2S and eliminates NH3. The secondary character of adamantane and neopentane demonstrates that hydrogenolysis of the aliphatic C-N bond does not take place over sulfided NiMo/Al2O3 below 340°C. Even though 1-adamantylamine can neither react by classic SN2, E1, and E2 reactions, nor via an imine or iminium cation, it formed 1-adamanethiol at 300°C. This reaction might take place by an SN1 reaction or by adsorption of the amine at a surface vacancy, followed by a shift of the adamantyl group to a neighboring sulfur ato

Stem rust resistance in South African wheat cultivars

The aim of this study was to attempt to identify reliable factors associated with dropout risk in a sample of 161 panic disorder patients treated with manualized cognitive behavior therapy. Four possible predictors of dropout were selected from the literature: level of education, treatment motivation, personality psychopathology, and initial symptom severity. Thirty-two patients (19.9%) were dropouts. Level of education and motivation were significantly associated with dropout, but the associations were small. Personality psychopathology and initial symptom severity were not associated with dropout. It is concluded that, at present, we are unable to make precise dropout risk predictions, even in a homogeneous group of patients treated using standardized treatment

Evidence for Innate and Adaptive Immune Responses in a Cohort of Intractable Pediatric Epilepsy Surgery Patients.

Brain-infiltrating lymphocytes (BILs) were isolated from resected brain tissue from 10 pediatric epilepsy patients who had undergone surgery for Hemimegalencephaly (HME) (n = 1), Tuberous sclerosis complex (TSC) (n = 2), Focal cortical dysplasia (FCD) (n = 4), and Rasmussen encephalitis (RE) (n = 3). Peripheral blood mononuclear cells (PBMCs) were also isolated from blood collected at the time of the surgery. Cells were immunostained with a panel of 20 antibody markers, and analyzed by mass cytometry. To identify and quantify the immune cell types in the samples, an unbiased clustering method was applied to the entire data set. More than 85 percent of the CD45+ cells isolated from resected RE brain tissue comprised T cells; by contrast NK cells and myeloid cells constituted 80-95 percent of the CD45+ cells isolated from the TSC and the FCD brain specimens. Three populations of myeloid cells made up >50 percent of all of the myeloid cells in all of the samples of which a population of HLA-DR+ CD11b+ CD4- cells comprised the vast majority of myeloid cells in the BIL fractions from the FCD and TSC cases. CD45RA+ HLA-DR- CD11b+ CD16+ NK cells constituted the major population of NK cells in the blood from all of the cases. This subset also comprised the majority of NK cells in BILs from the resected RE and HME brain tissue, whereas NK cells defined as CD45RA- HLA-DR+ CD11b- CD16- cells comprised 86-96 percent of the NK cells isolated from the FCD and TSC brain tissue. Thirteen different subsets of CD4 and CD8 αβ T cells and γδ T cells accounted for over 80% of the CD3+ T cells in all of the BIL and PBMC samples. At least 90 percent of the T cells in the RE BILs, 80 percent of the T cells in the HME BILs and 40-66 percent in the TSC and FCD BILs comprised activated antigen-experienced (CD45RO+ HLA-DR+ CD69+) T cells. We conclude that even in cases where there is no evidence for an infection or an immune disorder, activated peripheral immune cells may be present in epileptogenic areas of the brain, possibly in response to seizure-driven brain inflammation

REC: Fast sparse regression-based multicategory classification

Recent advance in technology enables researchers to gather and store enormous data sets with ultra high dimensionality. In bioinformatics, microarray and next generation sequencing technologies can produce data with tens of thousands of predictors of biomarkers. On the other hand, the corresponding sample sizes are often limited. For classification problems, to predict new observations with high accuracy, and to better understand the effect of predictors on classification, it is desirable, and often necessary, to train the classifier with variable selection. In the literature, sparse regularized classification techniques have been popular due to the ability of simultaneous classification and variable selection. Despite its success, such a sparse penalized method may have low computational speed, when the dimension of the problem is ultra high. To overcome this challenge, we propose a new sparse REgression based multicategory Classifier (REC). Our method uses a simplex to represent different categories of the classification problem. A major advantage of REC is that the optimization can be decoupled into smaller independent sparse penalized regression problems, and hence solved by using parallel computing. Consequently, REC enjoys an extraordinarily fast computational speed. Moreover, REC is able to provide class conditional probability estimation. Simulated examples and applications on microarray and next generation sequencing data suggest that REC is very competitive when compared to several existing methods

Transient self-assembly of molecular nanostructures driven by chemical fuels

Over the past decades, chemists have mastered the art of assembling small molecules into complex nanostructures using non-covalent interactions. The driving force for self-assembly is thermodynamics: the self-assembled structure is more stable than the separate components. However, biological self-assembly processes are often energetically uphill and require the consumption of chemical energy. This allows nature to control the activation and duration of chemical functions associated to the assembled state. Synthetic chemical systems that operate in the same way are essential for creating the next generation of intelligent, adaptive materials, nanomachines and delivery systems. This review focuses on synthetic molecular nanostructures which assemble under dissipative conditions. The chemical function associated to the transient assemblies is operational as long as chemical fuel is present

Local structural disorder and superconductivity in KxFe2-ySe2

We report significantly enhanced magnetic moment in K0.69(2)Fe1.45(1)Se2.00(1) single crystals with sharp Tc and bulk superconductivity obtained by postannealing and quenching process. There are two Fe sites in the K0.69(2)Fe1.45(1)Se2.00(1) unit cell: Fe1, which has higher symmetry with longer average Fe-Se bond length, and Fe2, which has lower symmetry with shorter average Fe-Se bond length. Temperature-dependent x-ray absorption fine-structure (XAFS) analysis results on quenched and as-grown K0.69(2)Fe1.45(1)Se2.00(1) crystals show that quenched K0.69(2)Fe1.45(1)Se2.00(1) have increased average Fe-Se bond length and decreased static disorder. Our results indicate that nonzero population of Fe1 sites is the key structural parameter that governs the bulk superconductivity. We also show clear evidence that Fe1 sites carry higher magnetic moment than Fe2 sites.Comment: 3 figures, 4 page