23,499 research outputs found
The possibility of positive selection for both F18(+) Escherichia coli and stress resistant pigs opens new perspectives for pig breeding
International audienc
Chiral two-dimensional electron gas in a periodic magnetic field
We study the energy spectrum and electronic properties of two-dimensional
electron gas in a periodic magnetic field of zero average with a symmetry of
triangular lattice. We demonstrate how the structure of electron energy bands
can be changed with the variation of the field strength, so that we can start
from nearly free electron gas and then transform it continuously to a system of
essentially localized chiral electron states. We find that the electrons near
some minima of the effective potential are responsible for occurrence of
dissipationless persistent currents creating a lattice of current contours. The
topological properties of the electron energy bands are also varied with the
intensity of periodic field. We calculated the topological Chern numbers of
several lower energy bands as a function of the field. The corresponding Hall
conductivity is nonzero and, when the Fermi level lies in the gap, it is
quantized.Comment: 10 pages;9 figures;42 reference
Exponential behavior of the interlayer exchange coupling across non-magnetic metallic superlattices
It is shown that the coupling between magnetic layers separated by
non-magnetic metallic superlattices can decay exponentially as a function of
the spacer thickness , as opposed to the usual decay. This effect
is due to the lack of constructive contributions to the coupling from extended
states across the spacer. The exponential behavior is obtained by properly
choosing the distinct metals and the superlattice unit cell composition.Comment: To appear in Phys. Rev.
Persistent systemic microbial translocation, inflammation, and intestinal damage during Clostridioides difficile infection
Background. Clostridioides difficile infection (CDI) might be complicated by the development of nosocomial bloodstream infection (n-BSI). Based on the hypothesis that alteration of the normal gut integrity is present during CDI, we evaluated markers of microbial translocation, inflammation, and intestinal damage in patients with CDI. Methods. Patients with documented CDI were enrolled in the study. For each subject, plasma samples were collected at T0 and T1 (before and after CDI therapy, respectively), and the following markers were evaluated: lipopolysaccharide-binding protein (LPB), EndoCab IgM, interleukin-6, intestinal fatty acid binding protein (I-FABP). Samples from nonhospitalized healthy controls were also included. The study population was divided into BSI+/BSI- and fecal microbiota transplantation (FMT) +/FMT- groups, according to the development of n-BSI and the receipt of FMT, respectively. Results. Overall, 45 subjects were included; 8 (17.7%) developed primary n-BSI. Markers of microbial translocation and intestinal damage significantly decreased between T0 and T1, however, without reaching values similar to controls (P < .0001). Compared with BSI-, a persistent high level of microbial translocation in the BSI+ group was observed. In the FMT+ group, markers of microbial translocation and inflammation at T1 tended to reach control values. Conclusions. CDI is associated with high levels of microbial translocation, inflammation, and intestinal damage, which are still present at clinical resolution of CDI. The role of residual mucosal perturbation and persistence of intestinal cell damage in the development of n-BSI following CDI, as well as the possible effect of FMT in the restoration of mucosal integrity, should be further investigated
Health-related quality of life and functional changes in DMD:A 12-month longitudinal cohort study
Family caregivers of people with amyotrophic lateral sclerosis (ALS) live stressful lives in which they spend most of their time caring for their loved ones and managing difficult situations, thereby reducing the time spent in taking care of themselves. This situation may last several years. Previous literature has widely highlighted that this situation reduces caregivers' quality of life and increases their psychological distress and risk of health problems, but there is a lack of studies that focus on psychological interventions for these situations. This qualitative study examined a pilot experience of two mutual support groups for family caregivers of people with ALS. The aim was to identify caregivers' needs, the prominent aspects of their experience, and to understand whether and how this intervention strategy might help them. Six partners (four men and two women) and six adult children (five women and one man) participated in the groups, which were conducted in northern Italy. After the support groups finished, participants underwent semi-structured interviews. The authors conducted a content analysis of the transcripts of the interviews and the 20 group sessions. The thematic areas identified were "caregiving," "being the son/daughter of a person with ALS," "being the partner of a person with ALS," "group experience" and "group evaluation." The caregiving experience was profoundly different depending on whether the caregiver was a son/daughter or a partner of a patient with ALS. Moreover, comparison with peers and mutual support helped participants to better cope with ALS and its consequences, to improve their care for their relatives and to overcome typical caregiver isolation. These results suggest the usefulness of involving communities in caregiver support in order to create new networks and activate personal and social resources for well-being
The aging male: investigation, treatment and monitoring of late-onset hypogonadism in males
Androgen deficiency in the aging male has become a topic of increasing interest and debate throughout the world. The demographics clearly demonstrate the increasing percentage of the population that is in the older age groups. The data also support the concept that testosterone falls progressively with age and that a significant percentage of men over the age of 60 years have serum testosterone levels that are below the lower limits of young adults (age 20-30 years) men. The principal questions raised by these observations are whether older hypogonadal men will benefit from testosterone treatment and what will be the risks associated with such intervention. The past decade has brought evidence of benefit of androgen treatment on multiple target organs of hypogonadal men and recent studies show short-term beneficial effects of testosterone in older men that are similar to those in younger men. Long-term data on the effects of testosterone treatment in the older population are limited and specific risk data on the prostate and cardiovascular systems are needed. Answers to key questions of functional benefits that may retard frailty of the elderly are not yet available. The recommendations described below were prepared for the International Society of Andrology (ISA) and the International Society for the Study of the Aging Male (ISSAM) following a panel discussion with active participation from the audience sponsored by the ISA on the topic at the 4th ISSAM Congress in Prague in February 2004.peer-reviewe
First report on Copepoda and Ostracoda (Crustacea) from northern Apenninic springs (N. Italy): a faunal and biogeographical account
The microcrustacean fauna of rheocrene and rheo-limnocrene springs in a protected area of the northern Apennines (Italy) was investigated for the first time. All springs are located in the catchments of the rivers Parma and Enza at altitudes between 800 and 1609 m a.s.l. Several of these springs are still in pristine condition while others are artificially modified or impacted to some degree. Surveys were carried out from April to June 2007. The sampling methods used for invertebrate fauna were: moss washing, artificial traps, and inserting drift tubes at the discharge point. A total of 14 harpacticoid, five cyclopoid, and 13 ostracod taxa were identified. Ostracods were mainly represented by crenophilic taxa; of particular interest was the collection of a specimen belonging to Pseudolimnocythere, a stygobiont genus with only two living species and a reduced distribution. Faunal affinities between northern Apenninic springs and those in other Italian mountain systems are discussed. The investigated ecosystems support a high microcrustacean diversity that must be adequately preserved due to the increasing direct and indirect impacts on mountain springs and groundwater resources
Antiferromagnetic interlayer exchange coupling across an amorphous metallic spacer layer
By means of magneto-optical Kerr effect we observe for the first time
antiferromagnetic coupling between ferromagnetic layers across an amorphous
metallic spacer layer. Biquadratic coupling occurs at the transition from a
ferromagnetically to an antiferromagnetically coupled region. Scanning
tunneling microscopy images of all involved layers are used to extract
thickness fluctuations and to verify the amorphous state of the spacer. The
observed antiferromagnetic coupling behavior is explained by RKKY interaction
taking into account the amorphous structure of the spacer material.Comment: Typset using RevTex, 4 pages with 4 figures (.eps
Effects from inhomogeneities in the chiral transition
We consider an approximation procedure to evaluate the finite-temperature
one-loop fermionic density in the presence of a chiral background field which
systematically incorporates effects from inhomogeneities in the chiral field
through a derivative expansion. We apply the method to the case of a simple
low-energy effective chiral model which is commonly used in the study of the
chiral phase transition, the linear sigma-model coupled to quarks. The
modifications in the effective potential and their consequences for the bubble
nucleation process are discussed.Comment: 11 pages, 5 figures. v2: appendix and references added, published
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