938 research outputs found
Superconducting Fluctuation Corrections to the Thermal Current in Granular Metals
The first-order superconducting fluctuation corrections to the thermal
conductivity of a granular metal are calculated. A suppression of thermal
conductivity proportional to is observed in a region not too
close to the critical temperature . As , a saturation of the
correction is found, and its sign depends on the ratio between the barrier
transparency and the critical temperature. In both regimes, the Wiedemann-Franz
law is violated.Comment: 9 pages, 7 figures. Replaced with published version. Important
change
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
Association of a homozygous GCK missense mutation with mild diabetes
Background: Homozygous inactivating GCK mutations have been repeatedly reported to cause severe hyperglycemia, presenting as permanent neonatal diabetes mellitus (PNDM). Conversely, only two cases of GCK homozygous mutations causing mild hyperglycemia have been so far described. We here report a novel GCK mutation (c.1116G>C, p.E372D), in a family with one homozygous member showing mild hyperglycemia. Methods: GCK mutational screening was carried out by Sanger sequencing. Computational analyses to investigate pathogenicity and molecular dynamics (MD) were performed for GCK-E372D and for previously described homozygous mutations associated with mild (n = 2) or severe (n = 1) hyperglycemia, used as references. Results: Of four mildly hyperglycemic family-members, three were heterozygous and one, diagnosed in the adulthood, was homozygous for GCK-E372D. Two nondiabetic family members carried no mutations. Fasting glucose (p = 0.016) and HbA1c (p = 0.035) correlated with the number of mutated alleles (0–2). In-silico predicted pathogenicity was not correlated with the four mutations’ severity. At MD, GCK-E372D conferred protein structure flexibility intermediate between mild and severe GCK mutations. Conclusions: We present the third case of homozygous GCK mutations associated with mild hyperglycemia, rather than PNDM. Our in-silico analyses support previous evidences suggesting that protein stability plays a role in determining clinical severity of GCK mutations
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
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
Impaired Activation of CA3 Pyramidal Neurons in the Epileptic Hippocampus.
We employed in vitro and ex vivo imaging tools to characterize the function of limbic neuron networks in pilocarpine-treated and age-matched, nonepileptic control (NEC) rats. Pilocarpine-treated animals represent an established model of mesial temporal lobe epilepsy. Intrinsic optical signal (IOS) analysis of hippocampal-entorhinal cortex (EC) slices obtained from epileptic rats 3 wk after pilocarpine-induced status epilepticus (SE) revealed hyperexcitability in many limbic areas, but not in CA3 and medial EC layer III. By visualizing immunopositivity for FosB/DeltaFosB-related proteins which accumulate in the nuclei of neurons activated by seizures we found that: (1) 24 h after SE, FosB/DeltaFosB immunoreactivity was absent in medial EC layer III, but abundant in dentate gyrus, hippocampus proper (including CA3) and subiculum; (2) FosB/DeltaFosB levels progressively diminished 3 and 7 d after SE, whereas remaining elevated (p < 0.01) in subiculum; (3) FosB/DeltaFosB levels sharply increased 2 wk after SE (and remained elevated up to 3 wk) in dentate gyrus and in most of the other areas but not in CA3. A conspicuous neuronal damage was noticed in medial EC layer III, whereas hippocampus was more preserved. IOS analysis of the stimulus-induced responses in slices 3 wk after SE demonstrated that IOSs in CA3 were lower (p < 0.05) than in NEC slices following dentate gyrus stimulation, but not when stimuli were delivered in CA3. These findings indicate that CA3 networks are hypoactive in comparison with other epileptic limbic areas. We propose that this feature may affect the ability of hippocampal outputs to control epileptiform synchronization in EC
Photovoltaic characterization of di-branched organic sensitizers for DSSCs.
In this work, the data on the effect of peripheral functionalization of a series of triphenylamine based di-branched dyes used as sensitizers in dye-sensitized solar cells are presented. The effect of different alkyl functionalities on the donor moiety upon the optical and photovoltaics parameters have been investigated in dye-sensitized solar cells (DSSCs) using a 10-μm TiO2 active layer. The absorption spectra, output efficiency, and incident photon to conversion efficiency of the DSSCs have been collected. The data can be exploited for properly designing efficient, stable, and industrially viable dyes for third generation solar devices
ANTIMICROBIAL PEPTIDES ARE TARGETS FOR BACTERIAL ADP-RIBOSYLTRANSFERASE ENZYMES
Background:
Human α-defensins (HNPs 1-3) are small cationic, amphipatic peptides with microbicidal activities. HNP-1 is the physiological target of ART1, an arginine (Arg) specific eucaryotic ribosyltransferase enzyme1. Mono ADP-ribosylation of Arg14 of HNP-1 modulates its biological activities2.
Bacterial exotoxins like Cholera Toxin (CT) by Vibrio cholerae, Heat Labile Enterotoxin (LT1) by Escherichia coli and Exoenzyme S (ExoS) by Pseudomonas aeruginosa are arginine ADP-ribosyltransferase enzymes that alter cell functions by modifying protein targets.
Objectives:
1. Evaluate the ADP ribosylation of HNP-1 by CT, LT1 and ExoS.
2. Purify modified peptides and identify the ADP-ribosylated Arg.
Methods:
ADP-ribosylation of HNP-1 will be evaluated with biotinilated NAD by western blot.
Purification of modified peptides will be performed by reverse phase HPLC.
Identification of modification will be performed by Maldi-Toff analysis.
Results:
1. CT and LT1 are effective in ADP-ribosylating HNP-1 as equal as the well known activity of ART1. On the other hand ExoS does not recognize HNP-1 as substrate.
2. Ongoing experiments are purifications and characterization of modified peptides by reverse-phase HPLC and Maldi-Toff analysis.
Conclusions:
1. The different ADP-ribosylating activities displayed by CT, LT1 and ExoS on HNP-1 might be explained with differences in microbial pathogenesis, as the toxins released by V. cholerae and E. coli are involved in the early stages of infections, during the interactions with surface epithelial cells, while ExoS by P. aeruginosa is active during blood dissemination, when the pathogen has already overcome epithelial barrier.
References:
1 Balducci et al., 1999, Am J Respir Cell Mol Biol, 21, 337-46
2 Paone et al., 2006, J Biol Chem, 281, 17054-6
Neuroplasticity in cholinergic projections from basal forebrain to the basolateral nucleus of amygdala in the kainic acid model of temporal lobe epilepsy
The amygdala is a cerebral region whose function is compromised in temporal lobe epilepsy (TLE). Patients with TLE present cognitive and emotional dysfunctions, of which impairments in recognizing facial expressions have been clearly attributed to amygdala damage. However, damage to the amygdala has been scarcely addressed, with the majority of studies focusing on the hippocampus. The aim of this study was to evaluate epilepsy-related plasticity of cholinergic projections to the basolateral nucleus (BL) of the amygdala. Adult rats received kainic acid (KA) injections and developed status epilepticus. Weeks later, they showed spontaneous recurrent seizures documented by behavioral observations. Changes in cholinergic innervation of the BL were investigated by using an antibody against the vesicular acetylcholine transporter (VAChT). In KA-treated rats, it was found that (i) the BL shrunk to 25% of its original size (p < 0.01 vs. controls, Student’s t-test), (ii) the density of vesicular acetylcholine transporter-immunoreactive (VAChT-IR) varicosities was unchanged, (iii) the volumes of VAChT-IR cell bodies projecting to the BL from the horizontal limb of the diagonal band of Broca, ventral pallidum, and subcommissural part of the substantia innominata were significantly increased (p < 0.05, Bonferroni correction). These results illustrate significant changes in the basal forebrain cholinergic cells projecting to the BL in the presence of spontaneous recurrent seizures
Il mondo slavo e l'Europa. Contributi presentati al VI Congresso Italiano di Slavistica (Torino, 28-30 settembre 2016)
The Italian-Russian parallel corpus in the national Russian corpus: a project for its enlargement, applications and future development
In this paper, we will introduce our project for enlarging the Italian-Russian parallel corpus of the NKRJA, presenting as well some current or possible and future applications. The enlargement, carried out since 2014, has allowed us to abandon the pilot phase and to reach about 4 million words. However, we expect to reach 20 million, which is the required size to have a reliable and balanced corpus, another essential qualitative feature of parallel corpora. Illustrating its possible applications, we will present some experimental uses for teaching translation at the University of Bologna and some research in the sphere of Russian-Italian Contrastive Linguistics (about the non-temporal value of Russian future tense and the expression of the relationship between clauses). Finally, we will briefly present a project based on the creation of a portal in order to constantly enlarge the parallel corpus and promote its use in linguistic and literary research, in Translation Studies and in the teaching of Russian as a second language
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