289 research outputs found
Examination of High-Torque Sandwich-Type Spherical Ultrasonic Motor Using with High-Power Multimode Annular Vibrating Stator
Spherical ultrasonic motors (SUSMs) that can operate with multiple degrees of freedom (MDOF) using only a single stator have high holding torque and high torque at low speed, which makes reduction gearing unnecessary. The simple structure of MDOF-SUSMs makes them useful as compact actuators, but their development is still insufficient for applications such as joints of humanoid robots and other systems that require MDOF and high torque. To increase the torque of a sandwich-type MDOF-SUSM, we have not only made the vibrating stator and spherical rotor larger but also improved the structure using three design concepts: (1) increasing the strength of all three vibration modes using multilayered piezoelectric actuators (MPAs) embedded in the stator, (2) enhancing the rigidity of the friction driving portion of the stator for transmitting more vibration force to the friction-driven rotor surface, and (3) making the support mechanism more stable. An MDOF-SUSM prototype was tested, and the maximum torques of rotation around the X(Y)-axis and Z-axis were measured as 1.48 N?m and 2.05 N?m, respectively. Moreover, the values for torque per unit weight of the stator were obtained as 0.87 N?m/kg for the X(Y)-axis and 1.20 N?m/kg for the Z-axis. These are larger than values reported for any other sandwich-type MDOF-SUSM of which we are aware. Hence, the new design concepts were shown to be effective for increasing torque. In addition, we measured the transient response and calculated the load characteristics of rotation around the rotor’s three orthogonal axes
High conservation combined with high plasticity: genomics and evolution of Borrelia bavariensis
BackgroundBorrelia bavariensis is one of the agents of Lyme Borreliosis (or Lyme disease) in Eurasia. The genome of the Borrelia burgdorferi sensu lato species complex, that includes B. bavariensis, is known to be very complex and fragmented making the assembly of whole genomes with next-generation sequencing data a challenge.ResultsWe present a genome reconstruction for 33 B. bavariensis isolates from Eurasia based on long-read (Pacific Bioscience, for three isolates) and short-read (Illumina) data. We show that the combination of both sequencing techniques allows proper genome reconstruction of all plasmids in most cases but use of a very close reference is necessary when only short-read sequencing data is available. B. bavariensis genomes combine a high degree of genetic conservation with high plasticity: all isolates share the main chromosome and five plasmids, but the repertoire of other plasmids is highly variable. In addition to plasmid losses and gains through horizontal transfer, we also observe several fusions between plasmids. Although European isolates of B. bavariensis have little diversity in genome content, there is some geographic structure to this variation. In contrast, each Asian isolate has a unique plasmid repertoire and we observe no geographically based differences between Japanese and Russian isolates. Comparing the genomes of Asian and European populations of B. bavariensis suggests that some genes which are markedly different between the two populations may be good candidates for adaptation to the tick vector, (Ixodes ricinus in Europe and I. persulcatus in Asia).ConclusionsWe present the characterization of genomes of a large sample of B. bavariensis isolates and show that their plasmid content is highly variable. This study opens the way for genomic studies seeking to understand host and vector adaptation as well as human pathogenicity in Eurasian Lyme Borreliosis agents.Peer reviewe
Cd, Hg, Pb, and As in European species of wild growing forest landscape fungi : a review
Kadmij (Cd), živo srebro (Hg), svinec (Pb) in arzen (As) so kovine, ki se naravno ali kot posledica človekove dejavnosti pojavljajo v okolju, tudi v gozdni krajini, kjer so rastišča številnih evropskih vrst gliv. Namen članka je bil pripraviti pregled vrst in količin izbranih kovin v trosnjakih gliv terprimerjati lastne raziskave, opravljene v različno onesnaženih območjih v Sloveniji (Zgornja Mežiška, Šaleška in Poljanska dolina), s podatki evropskih raziskav. Vsebnosti kovin v trosnjakih gliv iz neonesnaženih območij pravilomanajdemo v naslednjih intervalih: <0,5 mg/kg suhe teže (Cd), < 0,5 mg/kg do 10 mg/kg suhe teže (Hg), < 0,5 mg/kg do 5 mg/kg suhe teže (Pb) in < 0,5 mg/kg do 1 (2) mg/kg suhe teže (As). Na podlagi pregleda vsebnosti izbranih kovin v trosnjakih gliv ugotavljamo, da sta problematični kovini predvsem Cd in Hg. Omenjeni kovini lahko dosegata velike vsebnosti celo v glivah, ki rastejo v neonesnaženih območjih. Za vse analizirane kovin je značilno, da v trosnjakih gliv iz močno onesnaženih območji dosegajo velike, celo ekstemne vsebnosti, ki nekajkrat prekoračujejo vsebnosti iz neonesnaženih območij. Upoštevaje primerjavo z evropskimi raziskavami ugotavljamo, da je Zgornja Mežiška dolina obremenjena s Pb in Cd, Šaleška dolina pa s Cd in As.Metals, which originate from anthropogenic and natural activities, frequently occur in forest landscape with habitats of many European species of wild growing fungi. The presented review focuses on cadmium (Cd), mercury (Hg), lead (Pb), and arsenic (As) levels in fruiting bodies of wild growing European species of fungi of forest landscape. Furthermore, a comparison with studies of this kind performed in Slovenia was made with the aim to assess themetals levels in fungi from differently polluted areas in Slovenia (the Upper Meža Valley, the Šalek Valley, the Poljana Valley). The usual reported levels for most species grown in unpolluted areas are in the following ranges:Cd: < 0,5 mg/kg - 5 mg/kg dry weight (dw), Hg: < 0,5 mg/kg - 10 mg/kg dw, Pb: < 0,5 mg/kg - 5 mg/kg dw, As: < 0,5 mg/kg -1 (2) mg/kg dw (As), respectively. The presented data reveal that cadmium (Cd) and mercury (Hg) have probably been the most detrimental trace elements in fruiting bodies, which can reach increased levels even in unpolluted areas. It is evident for all analyzed trace elements that values can considerably increase in fungi picked in severely polluted areas. According to data regarding Slovene studies and comparison with other European studies, it is obvious that the Šalek Valley is enriched with Cd and As, while the Upper Meža Valley is considerably polluted with Pb and Cd
Vegetacija in ekologija barij v Sloveniji
We confirmed infection of 2 patients with Borrelia miyamotoi in Japan by retrospective surveillance of Lyme disease patients and detection of B. miyamotoi DNA in serum samples. One patient also showed seroconversion for antibody against recombinant glycerophosphodiester phosphodiesterase of B. miyamotoi. Indigenous relapsing fever should be considered a health concern in Japan
Description of three new bat-associated species of hard ticks (Acari, Ixodidae) from Japan
In Eurasia, the geographically most widespread ixodid tick species of the bat families Rhinolophidae Gray, Vespertilionidae Gray, and Miniopteridae Dobson were considered to belong to four species, Ixodes vespertilionis Koch, I. collaris Hornok, I. ariadnae Hornok, and I. simplex Neumann. Previous data attest that bat-associated tick species from Eastern Asia show remarkable genetic difference from the above four tick species, but in the absence of detailed morphological comparison these were regarded as conspecific. In this study we compensate for this lack of data on three bat-associated tick species, reporting their morphological comparison, as well as molecular and phylogenetic relationships. According to the results we describe the females of three tick species new to science, i.e., I. nipponrhinolophi Hornok &amp; Takano, sp. nov., I. fuliginosus Hornok &amp; Takano, sp. nov., and I. fujitai Hornok &amp; Takano, sp. nov. In case of all three new tick species the cytochrome c oxidase subunit (coxI) gene showed remarkably high sequence differences from the species that they previously were thought to belong to, well exceeding the average limit delineating ixodid tick species. This, as well as observed morphological differences fully justify their taxonomical status as new species
High degree of mitochondrial gene heterogeneity in the bat tick species Ixodes vespertilionis, I. ariadnae and I. simplex from Eurasia
Background: Phylogeographical studies allow precise genetic comparison of specimens, which were collected over large geographical ranges and belong to the same or closely related animal species. These methods have also been used to compare ticks of veterinary-medical importance. However, relevant data are missing in the case of ixodid ticks of bats, despite (1) the vast geographical range of both Ixodes vespertilionis and Ixodes simplex, and (2) the considerable uncertainty in their taxonomy, which is currently unresolvable by morphological clues. Methods: In the present study 21 ticks were selected from collections or were freshly removed from bats or cave walls in six European and four Asian countries. The DNA was extracted and PCRs were performed to amplify part of the cytochrome oxidase I (COI), 16S and 12S rDNA genes, followed by sequencing for identification and molecular-phylogenetic comparison. Results: No morphological differences were observed between Ixodes vespertilionis specimens from Spain and from other parts of Europe, but corresponding genotypes had only 94.6 % COI sequence identity. An I. vespertilionis specimen collected in Vietnam was different both morphologically and genetically (i.e. with only 84.1 % COI sequence identity in comparison with I. vespertilionis from Europe). Two ticks (collected in Vietnam and in Japan) formed a monophyletic clade and shared morphological features with I. ariadnae, recently described and hitherto only reported in Europe. In addition, two Asiatic specimens of I. simplex were shown to differ markedly from European genotypes of the same species. Phylogenetic relationships of ticks showed similar clustering patterns with those of their associated bat host species. Conclusions: Although all three ixodid bat tick species evaluated in the present study appear to be widespread in Eurasia, they exhibit pronounced genetic differences. Data of this study also reflect that I. vespertilionis may represent a species complex
Prognostic importance of survivin in breast cancer
Survivin is a member of the inhibitor of apoptosis (IAP) family, and is also involved in the regulation of cell division. Survivin is widely expressed in foetal tissues and in human cancers, but generally not in normal adult tissue. This study examined the expression of surviving protein in a series of 293 cases of invasive primary breast carcinoma. Survivin immunoreactivity was assessed using two different polyclonal antibodies, and evaluated semiquantitatively according to the percentage of cells demonstrating distinct nuclear and/or diffuse cytoplasmic staining. Overall, 60% of tumours were positive for survivin: 31% demonstrated nuclear staining only, 13% cytoplasmic only, and 16% of tumour cells demonstrated both nuclear and cytoplasmic staining. Statistical analysis revealed that survivin expression was independent of patient's age, tumour size, histological grade, nodal status, and oestrogen receptor status. In multivariate analysis, nuclear survivin expression was a significant independent prognostic indicator of favourable outcome both in relapse-free and overall survival (P<0.001 and P=0.01, respectively). In conclusion, our results show that survivin is frequently overexpressed in primary breast cancer. Nuclear expression is most common and is an independent prognostic indicator of good prognosis
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