142 research outputs found
The 0 and the pi phase Josephson coupling through an insulating barrier with magnetic impurities
We have studied temperature and field dependencies of the critical current
in the Nb-FeSi-Nb Josephson junction with tunneling
barrier formed by paramagnetic insulator. We demonstrate that in these
junctions the co-existence of both the 0 and the states within one tunnel
junction takes place which leads to the appearance of a sharp cusp in the
temperature dependence similar to the cusp found for the
transition in metallic junctions. This cusp is not related to the
temperature induced transition itself, but is caused by the different
temperature dependencies of the opposing 0 and supercurrents through the
barrier.Comment: Accepted in Physical Review
Portmanteau tests for linearity of Stationary Time Series
This paper considers the problem of testing for linearity of stationary time series. Portmanteau tests are discussed which are based on generalized correlations of residuals from a linear model (that is, autocorrelations and cross-correlations of different powers of the residuals). The finite-sample properties of the tests are assessed by means of Monte Carlo experiments. The tests are applied to 100 time series of stock returns
Nanogranular MgB2 thin films on SiC buffered Si substrates prepared by in-situ method
MgB2 thin films were deposited on SiC buffered Si substrates by sequential
electron beam evaporation of B-Mg bilayer followed by in-situ annealing. The
application of a SiC buffer layer enables the maximum annealing temperature of
830 C. The Transmission Electron Microscopy analysis confirms the growth of a
nanogranular MgB2 film and the presence of a Mg2Si compound at the surface of
the film. The 150-200 nm thick films show a maximum zero resistance critical
temperature TC0 above 37 K and a critical current density JC ~ 106 A/cm2 at
11K.Comment: 7 pages, 6 figures, submitted to Applied Physics Letter
Colorectal cancer liver metastases: laparoscopic and open radiofrequency-assisted surgery
Introduction: The liver is the most common site of colorectal metastases (colorectal liver metastases – CLM). Surgical treatment in combination with oncological therapy is the only potentially curative method. Unfortunately, only 10–25% of patients are suitable for surgery. Traditionally, open liver resection (OLR) is usually performed. However, laparoscopic liver resection (LLR) has become popular worldwide in the last two decades.
Aim: To evaluate the effectiveness and benefits of radiofrequency minor LLR of CLM in comparison with OLR.
Material and methods: The indication for surgery was CLM and the possibility to perform minor laparoscopic or OLR not exceeding two hepatic segments according to Couinaud’s classification.
Results: Sixty-six minor liver resections for CLM were performed. Twenty-five (37.9%) patients underwent a laparoscopic approach and 41 (62.1%) patients underwent OLR. The mean operative time was 166.4 min for LLR and 166.8 min for OLR. Average blood loss was 132.3 ±218.0 ml during LLR and 149.5 ±277.5 ml during OLR. Length of hospital stay was 8.4 ±2.0 days for LLR and 10.5 ±5.8 days for OLR. All resections were R0. There was no case of mortality. Postoperative complications were recognized in 9 (13.6%) patients: 8 in the group of OLR patients and 1 in the LLR group. The median survival time for LLR was 70.5 months and for OLR 61.9 months. The 5-year overall survival rate was higher for LLR vs. OLR – 82.1% vs. 69.8%. The average length of disease-free interval after LLR was greater (52.2 months) in comparison with OLR (49.4%). The 5-year disease-free interval was 63.2% for LLR and 58% for OLR.
Conclusions: Outcomes and oncological radicality of minor laparoscopic liver resections of CLM are comparable to outcomes of OLR.Web of Science10221220
New semi-spherical radiofrequency energy device for liver resection: an experimental study in pigs
The aim of this experimental study was to verify a new semi-spherical surgical tool for bipolar
radiofrequency liver ablation, which can solve some of the disadvantages of the commonly
used device, such as long duration of ablation. A total of 12 pigs which were randomly divided
into two groups were used. Each pig underwent resection of the two liver lobes. In group
1, pigs were treated with the commonly used device; in group 2 the newly developed semispherical
device was used. During surgery and the post-surgical period, many categories were
observed and later analyzed. The blood count and biochemistry were monitored on days 0,
14 and 30 from the operation. On day 14 since the liver resection, pigs underwent diagnostic
laparoscopy to evaluate their condition focusing on the site of the liver lobe resection. On day
30 after operation, all pigs were euthanized and subjected to histopathological examination.
Histopathological evaluation of thermal changes at the resection margin showed strong thermal
alteration in both groups. Data between both groups were compared using median test for
continuous variables and Fisher’s exact test for categorical variables. Statistical analyses were
performed with IBM SPSS software version 18.0. Statistical analysis of collected data did not
prove any significant (P < 0.05) differences between the commonly used device and the newly
designed surgical tool.Web of Science84439
Transcriptomic profiling of host-parasite interactions in the microsporidian <i>Trachipleistophora hominis</i>
BACKGROUND: Trachipleistophora hominis was isolated from an HIV/AIDS patient and is a member of a highly successful group of obligate intracellular parasites. METHODS: Here we have investigated the evolution of the parasite and the interplay between host and parasite gene expression using transcriptomics of T. hominis-infected rabbit kidney cells. RESULTS: T. hominis has about 30 % more genes than small-genome microsporidians. Highly expressed genes include those involved in growth, replication, defence against oxidative stress, and a large fraction of uncharacterised genes. Chaperones are also highly expressed and may buffer the deleterious effects of the large number of non-synonymous mutations observed in essential T. hominis genes. Host expression suggests a general cellular shutdown upon infection, but ATP, amino sugar and nucleotide sugar production appear enhanced, potentially providing the parasite with substrates it cannot make itself. Expression divergence of duplicated genes, including transporters used to acquire host metabolites, demonstrates ongoing functional diversification during microsporidian evolution. We identified overlapping transcription at more than 100 loci in the sparse T. hominis genome, demonstrating that this feature is not caused by genome compaction. The detection of additional transposons of insect origin strongly suggests that the natural host for T. hominis is an insect. CONCLUSIONS: Our results reveal that the evolution of contemporary microsporidian genomes is highly dynamic and innovative. Moreover, highly expressed T. hominis genes of unknown function include a cohort that are shared among all microsporidians, indicating that some strongly conserved features of the biology of these enormously successful parasites remain uncharacterised. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12864-015-1989-z) contains supplementary material, which is available to authorized users
Functionalized porous silica&maghemite core-shell nanoparticles for applications in medicine: design, synthesis, and immunotoxicity
Aim To determine cytotoxicity and effect of silica-coated
magnetic nanoparticles (MNPs) on immune response, in
particular lymphocyte proliferative activity, phagocytic activity,
and leukocyte respiratory burst and in vitro production
of interleukin-6 (IL-6) and 8 (IL-8), interferon-gamma
(IFN-γ), tumor necrosis factor-alpha (TNF-α), and granulocyte
macrophage colony stimulating factor (GM-CSF).
Methods Maghemite was prepared by coprecipitation of
iron salts with ammonia, oxidation with NaOCl and modified
by tetramethyl orthosilicate and aminosilanes. Particles
were characterized by transmission electron microscopy
(TEM), dynamic light scattering (DLS), Fourier-transform infrared
(FTIR), and X-ray photoelectron spectroscopy (XPS).
Cytotoxicity and lymphocyte proliferative activity were
assessed using [3H]-thymidine incorporation into DNA of
proliferating human peripheral blood cells. Phagocytic activity
and leukocyte respiratory burst were measured by
flow cytometry; cytokine levels in cell supernatants were
determined by ELISA.
Results γ-Fe2O3&SiO2-NH2 MNPs were 13 nm in size. According
to TEM, they were localized in the cell cytoplasm
and extracellular space. Neither cytotoxic effect nor significant
differences in T-lymphocyte and T-dependent Bcell
proliferative response were found at particle concentrations
0.12-75 μg/cm2 after 24, 48, and 72 h incubation.
Significantly increased production of IL-6 and 8, and GMCSF
cytokines was observed in the cells treated with 3, 15,
and 75 μg of particles/cm2 for 48 h and stimulated with
pokeweed mitogen (PHA). No significant changes in TNF-α
and IFN-γ production were observed. MNPs did not affect
phagocytic activity of monocytes and granulocytes when
added to cells for 24 and 48 h. Phagocytic respiratory burst
was significantly enhanced in the cultures exposed to 75
μg MNPs/cm2 for 48 h.
Conclusions The cytotoxicity and in vitro immunotoxicity
were found to be minimal in the newly developed porous
core-shell γ-Fe2O3&SiO2-NH2 magnetic nanoparticles
Dynamic changes in genomic and social structures in third millennium BCE central Europe
Europe’s prehistory oversaw dynamic and complex interactions of diverse societies, hitherto unexplored at detailed regional scales. Studying 271 human genomes dated ~4900 to 1600 BCE from the European heartland, Bohemia, we reveal unprecedented genetic changes and social processes. Major migrations preceded the arrival of “steppe” ancestry, and at ~2800 BCE, three genetically and culturally differentiated groups coexisted. Corded Ware appeared by 2900 BCE, were initially genetically diverse, did not derive all steppe ancestry from known Yamnaya, and assimilated females of diverse backgrounds. Both Corded Ware and Bell Beaker groups underwent dynamic changes, involving sharp reductions and complete replacements of Y-chromosomal diversity at ~2600 and ~2400 BCE, respectively, the latter accompanied by increased Neolithic-like ancestry. The Bronze Age saw new social organization emerge amid a ≥40% population turnover.Introduction Results - General sample overview - Bohemia before Corded Ware (pre-CW, before ~2800 BCE) - Corded Ware - Bell Beaker - EBA—Únětice culture Discussion Materials and methods - Processing sites for the newly reported individuals - Sampling - DNA extraction - DNA libraries and in-solution capture - Sequencing - Sex determination and authentication - Genotyping - Mitochondrial and Y chromosome haplogroups - Principal components analysis - Ancestry decomposition and admixture modeling - Y haplogroup frequency simulation
Measurement of the branching fractions of (B)over-bar -> D**l(-)(v)over-bar(l) decays in events tagged by a fully reconstructed B meson
We report a measurement of the branching fractions of D**- decays based on 417 fb-1 of data collected at the (4S) resonance with the BABAR detector at the PEP-II e+e- storage rings. Events are selected by fully reconstructing one of the B mesons in a hadronic decay mode. A fit to the invariant mass differences m(D(*))-m(D(*)) is performed to extract the signal yields of the different D** states. We observe the D**- decay modes corresponding to the four D** states predicted by heavy quark symmetry with a significance greater than 5 standard deviations including systematic uncertainties
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