1,042 research outputs found
Magnetic-field and chemical-potential effects on the low-energy separation
We show that in the presence of a magnetic field the usual low-energy
separation of the Hubbard chain is replaced by a ``'' and ``''
separation. Here and refer to small-momentum and low-energy independent
excitation modes which couple both to charge and spin. Importantly, we find the
exact generators of these excitations both in the electronic and pseudoparticle
basis. In the limit of zero magnetic field these generators become the usual
charge and spin fluctuation operators. The and elementary excitations
are associated with the and pseudoparticles, respectively. We also
study the separate pseudoparticle left and right conservation laws. In the
presence of the magnetic field the small-momentum and low-energy excitations
can be bosonized. However, the suitable bosonization corresponds to the and
pseudoparticle modes and not to the usual charge and spin fluctuations. We
evaluate exactly the commutator between the electronic-density operators. Its
spin-dependent factor is in general non diagonal and depends on the
interaction. The associate bosonic commutation relations characterize the
present unconventional low-energy separation.Comment: 29 pages, latex, submitted to Phys. Rev.
Conservation laws and bosonization in integrable Luttinger liquids
We examine and explain the Luttinger-liquid character of models solvable by
the Bethe ansatz by introducing a suitable bosonic operator algebra. In the
case of the Hubbard chain, this involves two bosonic algebras which apply to
{\it all} values of , electronic density, and magnetization. Only at zero
magnetization does this lead to the usual charge - spin separation. We show
that our ``pseudoparticle'' operator approach clarifies, unifies, and extends
several recent results, including the existence of independent right and left
equations of motion and the concept of ``pseudoparticle'' (also known as
``Bethe quasiparticle'').Comment: 12 pages, RevTeX, preprint CSI
Glycogen Synthase Kinase-3β Inhibition Attenuates the Development of Bleomycin-Induced Lung Injury:
Glycogen synthase kinase-3 (GSK-3) is an ubiquitous serine-threonine protein kinase that participates in a multitude of cellular processes and has recently been implicated in the pathophysiology of a number of diseases. The aim of this study is to investigate the effects of TDZD-8, a potent and selective GSK-3β inhibitor, on the development of lung injury caused by administration of bleomycin (BLM). Mice subjected to intra-tracheal administration of BLM developed significant lung injury characterized by marked neutrophil infiltration and tissue edema. An increase in immunoreactivity to nitrotyrosine, iNOS, TNF-α and IL-1β was also observed in the lungs of BLM-treated mice. In contrast, administration of BLM-treated mice with TDZD-8 (1 mg/kg daily) significantly reduced (I) the degree of lung injury, (II) the increase in staining (immunohistochemistry) for myeloperoxidase (MPO), nitrotyrosine, iNOS, TNF-α and IL-1β and (III) the degree of apoptosis, as evaluated by Bax and Bcl-2 immunoreactivity and TUNEL staining. Taken together, these results clearly demonstrate treatment with the GSK-3β inhibitor TDZD-8 reduces the development of lung injury and inflammation induced by BLM in mice
Anti-Transglutaminase Antibody Assay of the Culture Medium of Intestinal Biopsy Specimen Can Improve the Accuracy of Celiac Disease Diagnosis.
BACKGROUND:
We measured anti-transglutaminase (anti-tTG) antibody in the culture medium of intestinal biopsy specimens from patients with suspected celiac disease (CD) and evaluated the relationship between antibody production and severity of intestinal mucosal damage.
METHODS:
We performed diagnostic testing for CD on 273 consecutive patients. In addition to routine histologic evaluation of duodenal biopsy specimens, we assayed anti-tTG antibodies in serum and in the culture medium of duodenal biopsy specimens.
RESULTS:
CD was diagnosed in 191 of the 273 patients. Sensitivity and specificity of the serum anti-endomysium (EmA) and anti-tTG assays were 83% and 85% and 99% and 95%, respectively, and both had 88% diagnostic accuracy. EmA and anti-tTG assayed in the culture medium had 98% sensitivity, 100% specificity, and 98% diagnostic accuracy (vs serum assays; P <0.0001). Twenty-nine CD patient specimens (16%) were negative for serum anti-tTG and EmA; for 24 of these patients, anti-tTG assay of the culture medium was positive. The CD patients whose biopsy specimens were positive for serum antibodies showed the following intestinal histologies: total villous atrophy, 35%; severe villous atrophy, 25%; mild atrophy, 25%; villi with no atrophy but with increased intraepithelial lymphocytes, 15%. None of the CD patients whose specimens were negative for serum antibodies showed total or severe villous atrophy; 77% had mild villous atrophy, and 23% had no villous atrophy but had increased intraepithelial lymphocyte counts. Mild villous atrophy was also seen in specimens from approximately 15% of patients without CD.
CONCLUSION:
Anti-tTG assay of the culture medium of biopsy specimens can improve the accuracy of CD diagnosis in patients negative for serum antibodies
QT Indexes in Cirrhotic Patients: Relationship with Clinical Variables and Potential Diagnostic Predictive Value.
BACKGROUND AND AIMS:
A wide spectrum of cardiovascular changes characterizes cirrhosis, ranging from subclinical alterations to hyperkinetic syndrome. We looked for ECG markers of ventricular repolarization in a population of patients with cirrhosis in comparison to patients without cirrhosis and we investigated the relationship between these and other clinical and laboratory variables.
METHODS:
In 149 patients with cirrhosis and 152 controls, we measured QT maximum interval (QTmax), QT corrected interval (QTc), QT minimum interval (QTmin), QT dispersion (QTdisp), QT peak and T peak-to-end (TpTe).
RESULTS:
In subjects with cirrhosis, in comparison with controls, we observed a higher mean QTmax, mean QTc, mean QTmin, mean QTdisp and mean TpTe. At Cox regression analysis, diastolic blood pressure and beta-blocker treatment were significantly associated with mean QTmax, hypertension with mean QTmin and mean QTc, diastolic blood pressure, beta-blockers and ACE-inhibitors/ARBs with QT disp, and beta-blockers with TpTe. Analysis of ROC curves showed a significant area under curve towards cirrhosis diagnosis, respectively, for a cut-off value of >400 msec of QTmax, >360 msec of QTmin, >450 msec of QTc, >105 msec of TpTe and >55 msec of QTdisp
Fogli 609-596, Termini Imerese-Capo Plaia
Il Servizio Geologico Nazionale ha unificato i Fogli 609 "Termini Imerese" e 596 "Capo Plaia" in un unico Foglio denominato 609/596 "Termini Imerese-Capo Plaia" allo scopo di uniformare i rilievi e raccoglierne la descrizione in un unico volume delle Note Illustrative. Il Foglio 609/596 "Termini Imerese-Capo Plaia" della Carta Geologica d’Italia in scala 1:50.000 è stato realizzato nell’ambito del Progetto CARG con i fondi della Legge 67/88 - Legge 226/99 con una convenzione tra Servizio Geologico Nazionale ora ISPRA) e Regione Siciliana. Le aree ricadono interamente nella Provincia di Palermo, comprendono la fascia marina del Golfo di Termini Imerese fino al promontorio di Capo Plaia, la regione dei Monti di Termini Imerese e Trabia ad ovest e il settore occidentale del gruppo montuoso delle Madonie ad est. Tra questi rilievi si sviluppa un’ampio settore collinare inciso dai fiumi Torto e Imera settentrionale (o Fiume Grande)
Equalizing the Pixel Response of the Imaging Photoelectric Polarimeter On-Board the IXPE Mission
The Gas Pixel Detector is a gas detector, sensitive to the polarization of
X-rays, currently flying on-board IXPE - the first observatory dedicated to
X-ray polarimetry. It detects X-rays and their polarization by imaging the
ionization tracks generated by photoelectrons absorbed in the sensitive volume,
and then reconstructing the initial direction of the photoelectrons. The
primary ionization charge is multiplied and ultimately collected on a
finely-pixellated ASIC specifically developed for X-ray polarimetry. The signal
of individual pixels is processed independently and gain variations can be
substantial, of the order of 20%. Such variations need to be equalized to
correctly reconstruct the track shape, and therefore its polarization
direction. The method to do such equalization is presented here and is based on
the comparison between the mean charge of a pixel with respect to the other
pixels for equivalent events. The method is shown to finely equalize the
response of the detectors on board IXPE, allowing a better track reconstruction
and energy resolution, and can in principle be applied to any imaging detector
based on tracks.Comment: Accepted for publication in The Astronomical Journal. 10 pages, 19
figure
A framework for assessing healthcare facilities in low-resource settings : field studies in Benin and Uganda
Purpose. The aim of this paper is to present and validate a framework for assessing healthcare facilities in low-resource settings to collect evidence and inform policies on the harmonisation, regulation and contextualised design of medical devices.
Methods. A literature review and focus groups with several experts of medical device design, clinical engineering, health technology assessment and management, allowed the creation of a protocol, comprising two parts: a semi-structured interview and electrical safety measures.
Results. Three hospitals were assessed in Benin and three in Uganda. All the health centres resulted to be facing typical challenges for low-resource settings, including the lack of funding, expertise, a well-established maintenance program, spare parts and consumables, and unreliable power supplies.
Conclusion. As there is a paucity of information regarding low-resource settings, the proposed framework can be used by clinical or biomedical engineers to assess and thereby propose actions for improving the conditions of healthcare settings
Obesity and diabetes are major risk factors for epicardial adipose tissue inflammation
BACKGROUND. Epicardial adipose tissue (EAT) directly overlies the myocardium, with changes in its morphology and volume associated with myriad cardiovascular and metabolic diseases. However, EAT's immune structure and cellular characterization remain incompletely described. We aimed to define the immune phenotype of EAT in humans and compare such profiles across lean, obese, and diabetic patients. METHODS. We recruited 152 patients undergoing open-chest coronary artery bypass grafting (CABG), valve repair/replacement (VR) surgery, or combined CABG/VR. Patients' clinical and biochemical data and EAT, subcutaneous adipose tissue (SAT), and preoperative blood samples were collected. Immune cell profiling was evaluated by flow cytometry and complemented by gene expression studies of immune mediators. Bulk RNA-Seq was performed in EAT across metabolic profiles to assess whole-transcriptome changes observed in lean, obese, and diabetic groups. RESULTS. Flow cytometry analysis demonstrated EAT was highly enriched in adaptive immune (T and B) cells. Although overweight/obese and diabetic patients had similar EAT cellular profiles to lean control patients, the EAT exhibited significantly (P ≤ 0.01) raised expression of immune mediators, including IL-1, IL-6, TNF-α, and IFN-γ. These changes were not observed in SAT or blood. Neither underlying coronary artery disease nor the presence of hypertension significantly altered the immune profiles observed. Bulk RNA-Seq demonstrated significant alterations in metabolic and inflammatory pathways in the EAT of overweight/obese patients compared with lean controls. CONCLUSION. Adaptive immune cells are the predominant immune cell constituent in human EAT and SAT. The presence of underlying cardiometabolic conditions, specifically obesity and diabetes, rather than cardiac disease phenotype appears to alter the inflammatory profile of EAT. Obese states markedly alter EAT metabolic and inflammatory signaling genes, underlining the impact of obesity on the EAT transcriptome profile
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