Conductance through analytic constrictions

We study the dependence of the intrinsic conductance of a nanocontact on its shape by using the recursion-transfer-matrix method. Hour-glass, torus, and spherical shapes are defined through analytic potentials, the latter two serving as rough models for ring-like and spherical molecules, respectively. The sensitivity of the conductance to geometric details is analyzed and discussed. Strong resonance effects are found for a spherical contact weakly coupled to electron reservoirs.Comment: 7 pages, 12 figure

Effects of kefir on coccidial oocysts excretion and performance of dairy goat kids following weaning

The aim of this study was to investigate effects of kefir, a traditional source of probiotic, on coccidial oocysts excretion and on the performance of dairy goat kids following weaning. Twin kids were randomly allocated to one of two groups at weaning. Kids of the first group received 20 ml of kefir daily for 6 weeks (KEF), while kids in the control group were given a placebo (CON). Individual faecal samples were regularly (n = 18 per kid) taken to quantify the number of coccidial oocysts per gram of faeces (OpG). There were no differences between the groups in terms of body weight development (P > 0.05) and feed consumption. Kids of both groups were not able to consume enough feed to meet their nutrient requirements during the first 3 weeks following weaning. KEF had a lower frequency of OpG positive samples than CON (P = 0.043). Kefir did not affect the maximum oocyst excretion and age of the kids at the highest oocyst excretion (P > 0.05). KEF shed numerically 35% lower coccidial oocysts than the controls, which corresponded to a statistical tendency (P = 0.074) in lowering Log-OpG in comparison to CON. While KEF had a lower frequency of OpG positive samples and tended to shed lower OPG by around one-third, the frequency of diarrhea, level of highest oocyst excretion, and performance of the kids remained unaffected. Therefore, it is concluded that overall effects of kefir do not have a significant impact on sub-clinical infection and performance in weaned kids under relatively high-hygienic farming conditions

Lethal encephalitozoonosis in cyclophosphamide-treated rabbits

Encephalitozoonosis is an opportunistic infection in animals and humans. Its clinical form is observed in immunosuppressed hosts. We studied the occurrence of the manifest form of rabbit microsporidiosis under cyclophosphamide immunomodulation in 40 New Zealand rabbits. The experimental animals were intraperitoneally infected with 5 Ã 107Encephalitozoon cuniculispores. Two weeks after infection the animals were treated intraperitoneally with cyclophosphamide, first with 50 mg/kg and then with 15 mg/kg weekly during the 12-week experimental period. Positive controls were eitherE. cuniculi-infected or cyclophosphamide-immunosuppressed animals. The negative control rabbits remained untreated. Both clinical signs of encephalitozoonosis and depression of peripheral blood cell count developed between weeks 4 and 6 in the experimental animals which died during week 6 of the experiment. No clinical signs compatible with encephalitozoonosis were observed in any of the controls. The results suggest that immunosuppression induced by cyclophosphamide can give rise to a lethal form of encephalitozoonosis

Genome analysis and comparative genomics of a Giardia intestinalis assemblage E isolate

<p>Abstract</p> <p>Background</p> <p><it>Giardia intestinalis </it>is a protozoan parasite that causes diarrhea in a wide range of mammalian species. To further understand the genetic diversity between the <it>Giardia intestinalis </it>species, we have performed genome sequencing and analysis of a wild-type <it>Giardia intestinalis </it>sample from the assemblage E group, isolated from a pig.</p> <p>Results</p> <p>We identified 5012 protein coding genes, the majority of which are conserved compared to the previously sequenced genomes of the WB and GS strains in terms of microsynteny and sequence identity. Despite this, there is an unexpectedly large number of chromosomal rearrangements and several smaller structural changes that are present in all chromosomes. Novel members of the VSP, NEK Kinase and HCMP gene families were identified, which may reveal possible mechanisms for host specificity and new avenues for antigenic variation. We used comparative genomics of the three diverse <it>Giardia intestinalis </it>isolates P15, GS and WB to define a core proteome for this species complex and to identify lineage-specific genes. Extensive analyses of polymorphisms in the core proteome of <it>Giardia </it>revealed differential rates of divergence among cellular processes.</p> <p>Conclusions</p> <p>Our results indicate that despite a well conserved core of genes there is significant genome variation between <it>Giardia </it>isolates, both in terms of gene content, gene polymorphisms, structural chromosomal variations and surface molecule repertoires. This study improves the annotation of the <it>Giardia </it>genomes and enables the identification of functionally important variation.</p