Ultrasharp h-BN Nanocones and the Origin of Their High Mechanical Stiffness and Large Dipole Moment.

We report on experimental synthesis and theoretical studies of ultrasharp BN-nanocones. Using scanning and transmission electron microscopy, the cone-like morphology of synthesized products was confirmed. Theoretical analysis of the dipole moment nature in h-BN nanocones reveals that the moment has contributions from the polarity of B-N bonds and electronic flexoelectric effect associated with a curved h-BN lattice. The latter phenomenon is predicted on the basis of the extension of the theory of flexoelectric effects in the h-BN lattice through establishing universality of the linear dependence of flexoelectric dipole moments on local curvature in various nano- h-BN networks (nanotubes and fullerenes). Our study of the atomic structure response and its polarization under deformation of nanocones with different apex angles shows the advantageous properties of cones with the smallest angles.

Impact of Rabies Vaccination History on Attainment of an Adequate Antibody Titre Among Dogs Tested for International Travel Certification, Israel - 2010-2014.

Rabies is endemic in wildlife or domestic carnivore populations globally. Infection of domestic dogs is of particular concern in many areas. In regions where domestic animals are at risk of exposure to rabies virus, dogs should be routinely vaccinated against rabies to protect both pet and human populations. Many countries require demonstration of an adequate level of serum rabies neutralizing antibodies to permit entry of dogs during international travel. We analysed rabies titres of dogs seeking travel certification in Israel to assess demographic and vaccine history factors associated with antibody titres below the acceptable threshold for travel certification. Having received only one previous rabies vaccination and a longer duration since the most recent vaccination was received were primary risk factors for not achieving an adequate rabies virus neutralizing antibody titre for travel certification. These risk factors had stronger effects in younger animals, but were consistent for dogs of all ages. In particular, these findings reiterate the importance of administering at least two rabies vaccinations (the primo vaccination and subsequent booster) to ensure population-level protection against rabies in dogs globally.

Ionic Graphitization of Ultrathin Films of Ionic Compounds.

On the basis of ab initio density functional calculations, we performed a comprehensive investigation of the general graphitization tendency in rocksalt-type structures. In this paper, we determine the critical slab thickness for a range of ionic cubic crystal systems, below which a spontaneous conversion from a cubic to a layered graphitic-like structure occurs. This conversion is driven by surface energy reduction. Using only fundamental parameters of the compounds such as the Allen electronegativity and ionic radius of the metal atom, we also develop an analytical relation to estimate the critical number of layers.

Emergence of classical swine fever virus in Israel in 2009.

Classical swine fever (CSF) re-emerged in Israel in February 2009 after an absence of 62 years. The outbreak occurred on a domestic pig farm in northern Israel and affected domestic pigs and wild boar. On the basis of phylogenetic analysis of a 190 base pair fragment of the E2 glycoprotein gene, the Israeli CSF virus strain belonged to genotype 2.1 and was genetically most similar to a Chinese CSF virus strain.

Emergence of dog rabies in the northern region of Israel.

Between 1979 and 2000, foxes constituted the main reservoir of rabies in the Northern regions of Israel. Following the implementation of the fox-targeted oral vaccination programme (ORV) in 1998, rabies was eradicated from this area. Subsequently during 2004-2007, the biological and molecular characterization of the rabies isolates showed that stray dogs emerged as the main animal reservoir in Northern Israel while lower numbers of cases were reported in domestic animals. The virus isolates from foxes and dogs differed, in their molecular characterization, suggesting two distinct separate lineages. The transition from fox-mediated rabies to dog-mediated rabies is of great concern to public health because of the close contact between dogs and the human population.

Assessment of the efficacy of oral vaccination of livestock guardian dogs in the framework of oral rabies vaccination of wild canids in Israel.

Since 1956, red foxes (Vulpes vulpes) and golden jackals (Canis aureus) have been the primary vectors maintaining wildlife rabies in Israel. Oral rabies vaccination of wild canids, initiated in 1998, resulted in near-elimination of the disease in wildlife by 2005. In 2005 and 2006, an outbreak of rabies was observed in stray dogs in the vaccinated area of the Golan Heights, with no cases in foxes or jackals. Epidemiological investigations showed that the infected dogs were from territories across the border. This was confirmed by molecular analysis, which showed that the virus was different from rabies isolates endemic to this area. The objective of this study was to determine bait acceptance and the feasibility of oral rabies vaccination in packs of livestock guardian dogs. Coated sachets and fishmeal polymer baits of Raboral V-RG (Merial, USA) were tested in five different test zones. Both formats were hand-fed to individual dogs and to dogs belonging to dog packs. Bait uptake and consumption were observed in each dog. The estimated efficacy of oral rabies vaccination was very low (a maximum of 28%). Vaccine delivery problems were observed in dogs belonging to packs, whereby dominant animals consumed multiple baits and in competitive situations baits were swallowed whole. The uncertainty of oral vaccination necessitated turning to other methods to control this outbreak: stray dogs were removed and herd dogs were vaccinated parenterally. This study showed that oral rabies vaccination of dogs in packs using baits designed for wildlife would not be effective. Possibly, different baits or steps to circumvent competition within the pack will make this approach feasible.

Dislocation dynamics in multiwalled carbon nanotubes at high temperatures.

Dislocation dynamics dictate the mechanical behavior of materials. Dislocations in periodic crystalline materials have been well documented. On the contrary, dislocations in cylindrical carbon nanotubes, particularly in multiwalled carbon nanotubes (MWCNTs), remain almost unexplored. Here we report that a room temperature 1/2<0001> sessile dislocation in a MWCNT becomes highly mobile, as characterized by its glide, climb, and the glide-climb interactions, at temperatures of about 2000 degrees C. The dislocation glide leads to the cross-linking of different shells; dislocation climb creates nanocracks; and the interaction of two 1/2<0001> dislocations creates kinks. We found that dislocation loops act as channels for mass transport. These dislocation dynamics are drastically different from that in conventional periodic crystalline materials due to the cylindrical, highly anisotropic structures of MWCNTs.

Gate-induced switching and negative differential resistance in a single-molecule transistor: emergence of fixed and shifting states with molecular length.

The quantum transport of a gated polythiophene nanodevice is analyzed using density functional theory and nonequilibrium Green's function approach. For this typical molecular field effect transistor, we prove the existence of two main features of electronic components, i.e., negative differential resistance and good switching. Ab initio based explanations of these features are provided by distinguishing fixed and shifting conducting states, which are shown to arise from the interface and functional molecule, respectively. The results show that proper functional molecules can be used in conjunction with metallic electrodes to achieve basic electronics functionality at molecular length scales.

Rabies vaccination programme for red foxes (Vulpes vulpes) and golden jackals (Canis aureus) in Israel (1999-2004).

Since 1956, red foxes (Vulpes vulpes) and, to a lesser extent, golden jackals (Canis aureus), have been the primary vectors maintaining endemic wildlife rabies in Israel. Starting in the autumn of 1998, oral rabies vaccination campaigns have been conducted in Israel targeting these two wildlife species, with increasing yearly geographical extension. Significant data have been accumulated from an area of approximately 5,200 km2 in Northern Israel. In the spring of 2003 the project was extended to 14,000 km2 and in the autumn to 21,000 km2, covering almost all inhabited areas in Israel and the West Bank. A total of two million RABORAL V-RG (Merial) vaccine-filled baits were distributed bi-annually by plane or helicopter at 14-19 baits km2. Since the onset of oral vaccination activities in 1998, annual bait acceptance in the vaccination zones has been demonstrated by biomarker detection (with tetracycline) in 55 % (429/783) of bone samples of target animals submitted for diagnosis. In 1999 to 2004, vaccine contact and induction of immunity in animals collected from the vaccination zones were reflected by seroconversion in 66 of 284 animals (23 %). By the year 2004, rabies cases declined sharply in all progressively vaccinated areas.

Haematological and biochemical measurements in healthy, adult, free-ranging golden jackals (Canis aureus syriacus) held in captivity.

Blood from 31 healthy, free-ranging golden jackals held in captivity for seven days was collected while they were anaesthetised. Haematological and serum biochemical measurements were analysed and the 95 per cent confidence interval for each variable was compared with the reference value for domestic dogs. The measurements of their red blood cells were within the reference interval for dogs, but the jackals had higher white blood cell counts and eosinophil counts than dogs. The male jackals had a higher haematocrit, red blood cell count, mean corpuscular volume and mean corpuscular haemoglobin concentration, and a lower red blood cell distribution width than the female jackals. High activities of muscle enzymes were detected in many of the jackals, in several of which the activity of creatine kinase exceeded 5000 U/l; these were considered abnormal.

Rabies virus detection by RT-PCR in decomposed naturally infected brains.

The warm climate of Israel and mishandling of the cadavers during transit to the laboratory requires an accurate method for diagnosis of rabies in decomposed tissues. By using the reverse transcriptase polymerase chain reaction (RT-PCR) 10 decomposed brain samples that collected between 1998 and 2000 were diagnosed as negative by direct fluorescent antibody test (FAT), were found positive. Three of the 10 decomposed brains were confirmed as positive by isolation of rabies virus in tissue culture and by mouse inoculation (MIT) while the other seven decomposed samples were found positive only by RT-PCR. Direct sequencing and molecular analysis of a 328bp fragment of the N gene of all the rabies sequences confirmed their geographical origin. These results demonstrated the importance of the RT-PCR in the detection of rabies virus in decomposed naturally infected brains, especially in cases when the sample is not suitable for other laboratory assays. Thus, the RT-PCR can provide a positive diagnosis; however, when a negative result is obtained due to the nature of the decomposed tissue that can be caused by technical reasons and a false negative might be the case.

Antibodies to selected canine pathogens and infestation with intestinal helminths in golden jackals (Canis aureus) in Israel.

Blood and fecal samples, collected from 46 healthy adult free-ranging golden jackals captured in two different locations in Israel, were examined. A serological Study was conducted to investigate the prevalence of circulating antibodies reacting with four common canine pathogens: canine distemper virus (CDV), canine parvovirus (CPV), Ehrlichia canis and Leishmania infantum. Faecal flotation and haematological tests were also performed. The seroprevalence of CPV, E. canis, CDV, and L. infantum were 72.3% (34/47), 54.3% (25/46), 52.2% (24/46), and 6.5% (3/46) respectively. Faecal flotation tests revealed a high prevalence of Ancylostoma caninum (13/17, 76%) and a low prevalence of Dipilidium caninum infestation. Examination of blood smears revealed Hepatazoon canis gamonts in one jackal. Golden jackals are among the most common free-ranging carnivores in Israel and neighboring countries. Their habitats are in proximity to densely populated areas and they bear close phylogenic relation to the domestic dog. These facts, combined with the high prevalence of the jackals' exposure to the major canine pathogens demonstrated in this study, suggest that they may serve as a reservoir for the transmission of certain diseases to domestic dogs.

Cellular immune response cytokine expression during the initial stage of bovine leukemia virus (BLV) infection determines the disease progression to persistent lymphocytosis.

We have established experimental models of bovine leukemia virus (BLV) infection followed by progression to persistent lymphocytosis (PL) positive (BLV+PL+) or PL negative (BLV+PL-) stages of infection. Two out of six BLV infected animals developed PL+ 4 weeks after BLV infection. One other animal became PL+ late in the course of infection and three infected animals stayed PL-. These animals (PL-) exhibited transient lymphocytosis 3-4 weeks after infection and sustained PL- lymphocyte counts up to 24 weeks after infection. Competitive RT-PCR analysis of IFN-gamma mRNA expression revealed that peripheral blood mononuclear cells (PBMC) of animals with PL+ status developed by 4 weeks after infection had augmented IFN-gamma mRNA expression 3-4 weeks after BLV infection. However PBMC of animals that sustained a long-termed PL- lymphocyte count had elevated IFN-gamma mRNA expression 1-24 weeks after infection. Competitive RT-PCR analysis of IL-2 mRNA expression showed an increase in the levels of IL-2 mRNA in PL animals. Interleukin-10 (IL-10) mRNAs expression were elevated both in PL+ and PL- animals from 3 and 12 weeks after infection respectively. We suggest that early and extended expression of cellular response cytokines may delay the progression to PL+ in enzootic bovine leukemia.

Molecular epidemiology of rabies virus isolates from Israel and other middle- and Near-Eastern countries.

A total of 226 isolates of rabies virus from different areas of Israel, including three human isolates and one sample from South Lebanon were identified between 1993 and 1998 by direct immunofluorescence using monoclonal antibodies to the viral nucleoprotein (N). An epidemiological survey based on nucleotide sequence analysis of 328 bp from the C terminus of the N coding region and the noncoding region between the nucleoprotein and the phosphoprotein (NS gene) was performed. Phylogenetic analysis of the isolates from Israel showed that they were related geographically, but not according to host species. Five variants, related groups distributed among four geographical regions, were identified. In each region, rabies virus was isolated from more than one animal species. A comparison of the sequence analysis of rabies virus samples from the rest of world revealed a 2-nucleotide change that distinguished the Middle East variants from the rest.

Experimental infection of calves with bovine leukemia virus (BLV): an applicable model of a retroviral infection.

An experimental model of chronic infection with bovine leukemia virus (BLV) was established in young calves within a relatively short time. In the sera of all infected calves, precipitating antibodies were detected within 5 weeks after infection but upon disease progression pattern of cellular profiles varied. Three calves exhibited transient lymphocytosis 3-5 weeks after infection, two became persistent lymphocytotic (PL+) by that time and one stayed non-lymphocytotic (PL-) for 11 weeks and became PL+ after 4.5 months. Eventually all infected calves became PL+ by the end of the experiment, 6-12 months after infection. Increase of total counts of peripheral blood mononuclear cells (PBMC) related to polyclonal expansion of B-cells. The latter was assessed in all infected calves where the expansion of CD5-bearing cells (B+ CD5+) correlated with increase or decrease of total PBMC counts. Other cell populations such as CD4 and CD8 were also affected. Percentages decreased by 5 weeks after experimental infection to about half their original values though actual cell numbers stayed relatively stable. The experimental model we established compared well with field cases of naturally BLV-infected cattle and thus permitted the investigation of the disease at early stages of infection.

Probable toxicosis in cattle in Israel caused by the oak Quercus calliprinos.

A probable outbreak of oak (Quercus calliprinos) toxicosis in a herd of beef cattle--heifers and first-calving cows--grazing in the Judean foothills of Israel is described. Toxicosis probably occurred because of the consumption of oak leaves and buds during a period of pasture scarcity without any feed supplementation. A progressive syndrome of wasting, dullness, anorexia, polyuria, nephrosis, constipation and recumbency, culminating in death, was seen. A high mortality rate of 83% (38/46 animals) was noted. The clinical-pathological findings revealed increases in blood urea, creatinine, aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), creatine kinase (CK), lactate dehydrogenase (LDH) and inorganic phosphorus. Decreases were found in alkaline phosphatase (ALP), total serum protein, albumin (ALB), triglyceride (TG), calcium (Ca), magnesium (Mg), sodium (Na) and chloride (CI). The main pathological findings were severe nephrosis, chronic interstitial nephritis, and occasional intestinal ulceration. On the basis of epidemiology, clinical signs, clinical-pathological and pathological findings and renal histology, a tentative diagnosis of oak toxicosis was made.