1,041 research outputs found
Weak localization effects in granular metals
The weak localization correction to the conductivity of a granular metal is
calculated using the diagrammatic technique in the reciprocal grain lattice
representation. The properties of this correction are very similar to that one
in disordered metal, with the replacement of the electron mean free path by the grain diameter and the dimensionless conductance by the
tunnelling dimensionless conductance . In particular, we demonstrate
that at zero temperature no conducting phase can exist for dimensions . We also analyze the WL correction to magnetoconductivity in the weak field
limit.Comment: 4 pages, 3 figures; minor corrections adde
Magnetic-field-induced Luttinger liquid
It is shown that a strong magnetic field applied to a bulk metal induces a
Luttinger-liquid phase. This phase is characterized by the zero-bias anomaly in
tunneling: the tunneling conductance scales as a power-law of voltage or
temperature. The tunneling exponent increases with the magnetic field as BlnB.
The zero-bias anomaly is most pronounced for tunneling with the field applied
perpendicular to the plane of the tunneling junction.Comment: a reference added, minor typos correcte
Surgical site infections in treatment of musculoskeletal tumors: experience from a single oncologic orthopedic institution
Objective: Limb-sparing surgery is the mainstay treatment for musculoskeletal tumors thanks to advances in surgical techniques, imaging modalities and multimodal therapies. As patients survive longer, plastic reconstructive procedures and revision surgery are increasingly required after tumor excision. Infection rate is reported to be up to 20% after prosthetic replacement and 30-44% after pelvic resection. The purpose of this study was to investigate the incidence of surgical site infections (SSIs), identifying the causative microrganisms related to specific surgical procedures and significant risk factors for SSIs. Methods: We retrospectively reviewed 723 interventions performed between 2009 and 2015 for oncological conditions. Non neoplastic lesions, aseptic wound complications, non-skeletally mature patients were excluded. Standardised antibiotic prophylaxis was used for different surgical procedures and maintained until removal of surgical drains. Results: Without considering tumor types and surgical sites, the overall infection rate was 8.7% (63/724). Infection occurred in prosthetic reconstruction with an incidence rate of 7.8%, whereas almost half of patients having undergone pelvic surgery got infected and about 20% of patients with spinal surgery and amputations were infected. Pelvic location, malignancy and radiotherapy were related to a major risk of SSI. The causative pathogens were detected in all examined cases. The most frequent pathogens detected by culture included Staphylococcus aureus (27 cases, 47.4%) and S. epidermidis (10 cases, 17.5%). Among the S. aureus cases, 10/27 cases (37%) were methicillin-resistant S. aureus (MRSA). Sixty-three out of 130 microbial isolations (47.7%) were nosocomial ALERT organisms. Conclusion: Oncologic orthopedic surgery is burdened by frequent and challenging SSIs because of extensive soft tissues dissection, long operative times and poor skin conditions. Patients are immunosuppressed and often have concomitant comorbidities predisposing to SSIs. Monitoring of local bacterial aetiology of SSIs could help orthopedic oncologic specialized centres in achieving the optimisation of antibiotic prophylactic regimens
Nucleation of superconducting pairing states at mesoscopic scales at zero temperature
We find the spin polarized disordered Fermi liquids are unstable to the
nucleation of superconducting pairing states at mesoscopic scales even when
magnetic fields which polarize the spins are substantially higher than the
critical one. We study the probability of finding superconducting pairing
states at mesoscopic scales in this limit. We find that the distribution
function depends only on the film conductance. The typical length scale at
which pairing takes place is universal, and decreases when the magnetic field
is increased. The number density of these states determines the strength of the
random exchange interactions between mesoscopic pairing states.Comment: 11 pages, no figure
Many-Body Effects on Tunneling of Electrons in Magnetic-Field-Induced Quasi One-Dimensional Electron Systems in Semiconductor Nanowhiskers
Effects of the electron-electron interaction on tunneling in a semiconductor
nanowhisker are studied in a magnetic quantum limit. We consider the system
with which bulk and edge states coexist. In bulk states, the temperature
dependence of the transmission probability is qualitatively similar to that of
a one-dimensional electron system. We investigate contributions of edge states
on transmission probability in bulk states. Those contributions can be
neglected within our approximation which takes into account only most divergent
terms at low temperatures.Comment: 9 pages, 6 figure
Dose-Dependent Prevention of Fibrosis in Aorta of Salt-Loaded Stroke-Prone Spontaneously Hypertensive Rats by Combined Delapril and Indapamide treatment.
Combined treatment with the angiotensin-converting enzyme (ACE) inhibitor delapril and the diuretic indapamide prevented vascular damage in vital organs of salt-loaded stroke-prone spontaneously hypertensive rats (SHRsp). Whether the changes occurring after long-term hypertension could also be modulated in large arteries was investigated. Two-month-old SHRsp were salt loaded and treated with the drug regimen until they reached 50 +/- 10 mortality or around midlife. In a first experiment, delapril (12 mg/kg) and indapamide (1 mg/kg) were administered daily separately or in combination. In the second dose-finding experiment, delapril (6, 3, 1.5 mg/kg) and indapamide (0.5, 0.25, 0.125 mg/kg) in decreasing dose combinations were analyzed. Ultrastructural, histomorphometric, and biochemical studies were performed on the thoracic aorta. When compared with delapril (12 mg/kg) or indapamide (1 mg/kg) administered individually for 5 months, the combination 12 + 1 mg/kg was able to prevent the increase in extracellular matrix deposition observed in other treatment groups, as assessed by histomorphometry or 4-OH-proline biochemical determination. In the second experiment, a half-dose (delapril 6 mg/kg + indapamide 0.5 mg/kg) combination was similarly effective in counteracting fibrosis, but the other doses progressively failed. In the first experiment, the combination had a stabilizing effect on hypertension and stimulated diuresis. In the second experiment, arterial blood pressure values and sodium balance were not consistently affected by the treatments that antagonized fibrosis (i.e., delapril 6 mg/kg + indapamide 0.5 mg/kg and, less efficiently, delapril 3 mg/kg + indapamide 0.25 mg/kg). These results suggest that indapamide interacts with ACE inhibitors to limit aortic fibrosis independent of any well-established mechanism
Vitis vinifera subsp. sylvestris and sativa; so far, so close: a 20 SSR based comparison of the two taxa
In Vitis vinifera L., the hypothesis of secondary domestication center, located along the wild progenitor distribution areas, is suggestive and credible even if up to now close parentage relationships between domestic (Vitis vinifera L. subsp. sativa (DC.) Hegi) and wild (Vitis vinifera L. subsp. sylvestris (Gmel.) Hegi) grapevines have not been detected, possibly due to century long separation of the two subspecies. The aim of this work was to verify the possibility of tracing a flow between the two compartments basing on molecular data and thanks to the availability of a huge dataset comprising 645 wild and more than 1400 cultivated samples. Twenty SSR loci were used to describe and genotype both sylvestris and sativa compartments. The sylvestris samples were all collected in the frame of a three year census in Italy and are representative of the Italian distribution range from north to south. The cultivated sativa accessions mainly (1231 samples) belong to the Vassal (INRA-Montpellier) collection, while the remaining (200) were selected in the frame of the Italian grapevine germplasm. Results highlighted a high level of genetic diversity for both wild and cultivated groups. STRUCTURE analysis clearly evidenced the separation of the two compartments and no first or second degree relationships were evidenced between the two subspecies
Vitis vinifera subsp. sylvestris and sativa; so far, so close: a 20 SSR based comparison of the two taxa
In Vitis vinifera L., the hypothesis of secondary domestication center, located along the wild progenitor distribution areas, is suggestive and credible even if up to now close parentage relationships between domestic (Vitis vinifera L. subsp. sativa (DC.) Hegi) and wild (Vitis vinifera L. subsp. sylvestris (Gmel.) Hegi) grapevines have not been detected, possibly due to century long separation of the two subspecies. The aim of this work was to verify the possibility of tracing a flow between the two compartments basing on molecular data and thanks to the availability of a huge dataset comprising 645 wild and more than 1400 cultivated samples. Twenty SSR loci were used to describe and genotype both sylvestris and sativa compartments. The sylvestris samples were all collected in the frame of a three year census in Italy and are representative of the Italian distribution range from north to south. The cultivated sativa accessions mainly (1231 samples) belong to the Vassal (INRA-Montpellier) collection, while the remaining (200) were selected in the frame of the Italian grapevine germplasm. Results highlighted a high level of genetic diversity for both wild and cultivated groups. STRUCTURE analysis clearly evidenced the separation of the two compartments and no first or second degree relationships were evidenced between the two subspecies
Generalized Fock spaces and the Stirling numbers
The Bargmann-Fock-Segal space plays an important role in mathematical
physics, and has been extended into a number of directions. In the present
paper we imbed this space into a Gelfand triple. The spaces forming the
Fr\'echet part (i.e. the space of test functions) of the triple are
characterized both in a geometric way and in terms of the adjoint of
multiplication by the complex variable, using the Stirling numbers of the
second kind. The dual of the space of test functions has a topological algebra
structure, of the kind introduced and studied by the first named author and G.
Salomon.Comment: revised versio
- …