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Background: The ectoparasitic mite Varroa destructor has emerged as the primary pest of domestic honey bees (Apis mellifera). Here we present an initial survey of the V. destructor genome carried out to advance our understanding of Varroa biology and to identify new avenues for mite control. This sequence survey provides immediate resources for molecular and population-genetic analyses of Varroa-Apis interactions and defines the challenges ahead for a comprehensive Varroa genome project. Results: The genome size was estimated by flow cytometry to be 565 Mbp, larger than most sequenced insects but modest relative to some other Acari. Genomic DNA pooled from similar to 1,000 mites was sequenced to 4.3x coverage with 454 pyrosequencing. The 2.4 Gbp of sequencing reads were assembled into 184,094 contigs with an N50 of 2,262 bp, totaling 294 Mbp of sequence after filtering. Genic sequences with homology to other eukaryotic genomes were identified on 13,031 of these contigs, totaling 31.3 Mbp. Alignment of protein sequence blocks conserved among V. destructor and four other arthropod genomes indicated a higher level of sequence divergence within this mite lineage relative to the tick Ixodes scapularis. A number of microbes potentially associated with V. destructor were identified in the sequence survey, including similar to 300 Kbp of sequence deriving from one or more bacterial species of the Actinomycetales. The presence of this bacterium was confirmed in individual mites by PCR assay, but varied significantly by age and sex of mites. Fragments of a novel virus related to the Baculoviridae were also identified in the survey. The rate of single nucleotide polymorphisms (SNPs) in the pooled mites was estimated to be 6.2 x 10(-5)per bp, a low rate consistent with the historical demography and life history of the species. Conclusions: This survey has provided general tools for the research community and novel directions for investigating the biology and control of Varroa m

Nanochannel alumina templates are used as templates for fabrication of porous gold nanowire arrays by a direct electrodeposition method. After modification with glucose oxidase, a porous gold nanowire-array electrode is shown to be an excellent electrochemical biosensor for the detection of glucose. The picture shows an SEM image of a nanowire array after removal of the alumina template by acid dissolution. We report the fabrication of porous gold nanowire arrays by means of a one-step electrodeposition method utilizing nanochannel alumina templates. The microstructure of gold nanowires depends strongly on the current density. The formation of porous gold nanowires is attributed to disperse crystallization under conditions of low nucleation rate. Interfacial electron transport through the porous gold nanowires is studied by electrochemical impedance spectroscopy. Cyclic voltammetric studies on the porous gold nanowire arrays reveal a low-potential electrocatalytic response towards hydrogen peroxide. The properties of the glucose oxidase modified porous gold nanowire array electrode are elucidated and compared with those of nonporous enzyme electrodes. The glucose oxidase modified porous gold nanowire-array electrode is shown to be an excellent electrochemical biosensor for the detection of glucose.

Nanochannel alumina templates are used as templates for fabrication of porous gold nanowire arrays by a direct electrodeposition method. After modification with glucose oxidase, a porous gold nanowire-array electrode is shown to be an excellent electrochemical biosensor for the detection of glucose. The picture shows an SEM image of a nanowire array after removal of the alumina template by acid dissolution. We report the fabrication of porous gold nanowire arrays by means of a one-step electrodeposition method utilizing nanochannel alumina templates. The microstructure of gold nanowires depends strongly on the current density. The formation of porous gold nanowires is attributed to disperse crystallization under conditions of low nucleation rate. Interfacial electron transport through the porous gold nanowires is studied by electrochemical impedance spectroscopy. Cyclic voltammetric studies on the porous gold nanowire arrays reveal a low-potential electrocatalytic response towards hydrogen peroxide. The properties of the glucose oxidase modified porous gold nanowire array electrode are elucidated and compared with those of nonporous enzyme electrodes. The glucose oxidase modified porous gold nanowire-array electrode is shown to be an excellent electrochemical biosensor for the detection of glucose.

Bundles of B- and N-doped single-walled carbon nanotubes (SWNTs) containing up to approximately 10 at% B and up to approximately 2 at% N were synthesized at high yields under thermo-chemical treatment of pure C SWNT bundles and B2O3 in a flowing nitrogen atmosphere. The bundles were characterized by means of high-resolution transmission electron microscopy and electron energy loss spectroscopy. The effects of synthesis temperature (1503-1773 K) and time (30-240 min) on the B and N contents and yield of the SWNT bundles were determined. The maximum yield of the B- and N-doped SWNT bundles was obtained under synthesis at 1553 K over 30 min. Atomic structure and morphology of individual SWNTs in the bundles, in particular, packing of doped SWNTs, helicity distribution, encapsulation of fullerene-like clusters, diameter and shell number variations were studied. The synthesized SWNTs in the bundles were stacked in a honeycomb array with the uniform inter-tube spacing of approximately 0.3 nm. No preferable orientation for the graphene-like tubular shells was found, i.e. both zigzag and armchair edges were observed with approximately equal proportions. Frequently, diameter increase took place for the outer tubes in a bundle and for isolated SWNTs. C-based or BN-based fullerene-like encapsulates were observed in individual SWNTs. Carbon oxidation by the B2O3 vapor and B and N substitution for C is thought to underlie the doping of C SWNTs. The substitution reaction temperature-time limits with respect to the morphological stability of B- and N-doped SWNT bundles are finally elucidated.

The following features of multiwalled BN nanotubes were discovered using a field emission high-resolution analytical transmission electron microscope: (i) coexistence of hexagonal and rhombohedral stacking in nanotube shell assembly; (ii) flattening of nanotube cross section, which makes possible clear atomic resolution of the core structure in a three-shelled nanotube; and (iii) change in chirality of tubular layers from armchair to zigzag arrangement in a 30° double-walled nanotube kink, as revealed by atomically resolved images of tube wall segments.

Here we report on the precise structural investigation of multiwalled boron nitride (BN) nanotubes by means of high-resolution transmission electron microscopy and electron energy loss spectroscopy. The nanotubes were produced from carbon nanotubes by applying a recently discovered technique: a substitution chemical reaction [W. Han, Y. Bando, K. Kurashima, and T. Sato, Appl. Phys. Lett. 73, 3085 (1998)]. It is found that in contrast to the starting carbon nanotubes, which exhibited large number of shells (typically >10), a significant proportion of buckled and corrugated graphene-like sheets, poor degree of graphitization, and wide distribution of helicities, the resultant BN nanotubes revealed perfectly straight shapes, limited number of shells (typically 2-6), and remarkable ordering of the graphene-like sheets in the so-called nonhelical "zig-zag" fashion with the [101̄0] direction parallel to the tube axis.

Boron nitride (BN) multi-walled (MWNT) or single-walled (SWNT) nanotubes were synthesized from carbon MWNT and SWNT templates, respectively, under heating of C nanotubes together with boron trioxide in a flowing nitrogen atmosphere. B and N atom substitution for C atoms in the nanotubular shells during C oxidation by the B2O3 vapor in the N2 flow is thought to underlie the formation mechanism. Structural and chemical BN MWNT/SWNT analyses were performed by means of high-resolution electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS), respectively. In particular, BN MWNT shell structure and defects, and electron irradiation stability were studied. Finally, the prospects of using the substitution technique for the synthesis of other advanced nanostructures made of BN(nanorods, nanoplates and nanocenes) are discussed.

High-resolution transmission electron microscopy (HRTEM) observations were carried out on the untreated C single-walled carbon nanotube (SWNT) produced under laser vaporization technique. Micrographs were taken at room temperature at a magnification of 4 × 505 on a negative film. The set of images were taken for each particular isolated tube or a SWNT bundle at the vicinity of the optimal defocus value of the microscope. The results provide the first experimental evidence of achieving atomic resolution of an individual C SWNT by means of HRTEM with a field emission gun.

A series of three studies were carried out in which the manipulation of external environments in an experimental setting resulted in subjects choosing organization designs contrary to what would be prescribed by current contingency theory. Implications for the directionality of organization-environment relationships are also discussed. (Author)

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