596 research outputs found

    Binary Reactive Adsorbate on a Random Catalytic Substrate

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    We study the equilibrium properties of a model for a binary mixture of catalytically-reactive monomers adsorbed on a two-dimensional substrate decorated by randomly placed catalytic bonds. The interacting AA and BB monomer species undergo continuous exchanges with particle reservoirs and react (A+BA + B \to \emptyset) as soon as a pair of unlike particles appears on sites connected by a catalytic bond. For the case of annealed disorder in the placement of the catalytic bonds this model can be mapped onto a classical spin model with spin values S=1,0,+1S = -1,0,+1, with effective couplings dependent on the temperature and on the mean density qq of catalytic bonds. This allows us to exploit the mean-field theory developed for the latter to determine the phase diagram as a function of qq in the (symmetric) case in which the chemical potentials of the particle reservoirs, as well as the AAA-A and BBB-B interactions are equal.Comment: 12 pages, 4 figure

    Central bisectionectomy – a feasible alternative for centrally located liver tumors

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    Clinica de Chirurgie Generală şi Transplant Hepatic, I.C.Fundeni, Bucureşti, România, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Bisectionectomia centrală reprezintă rezecția hepatică a segmentelor 4a, 4b, 5 și 8, definite astfel de sistemul Brisbane. Denumită anterior în diferite feluri (mesohepatectomie, hepatectomie centrală, lobectomie centrală) bisectionectomia centrală este operația de elecție pentru tumorile hepatice situate în segmentele centrale, și este de preferat rezecțiilor hepatice extinse (trisectionectomia dreaptă/stângă) pentru că minimalizează riscul insuficienței hepatice postoperatorii. Prezentare de caz: Pacienta în vârstă de 54 de ani cu dureri în hipocondrul drept, scădere ponderală cca. 8 kg / 2 luni. Bioumoral: AFP, CA 19.9 și ACE – în limite normale / AgHbs, Ac Anti-HBc, Ac Anti-HCV – negative. EDS/EDI – de aspect normal, prezintă la examenul CT o formațiune tumorală hepatică situată central (segmentele 4a, 4b, 5 și 8) ce înglobează VHM, la distanță de bifurcația venei porte. Se practică o bisectionectomie centrală, cu ligaturarea pediculilor vasculari glissonieni drept anterior (seg. 5 și 8) și stâng medial (seg. 4a și 4b). Transecțiunea parenchimului hepatic se efectuează folosindu-se “SONOPET”. Cu evoluție postoperatorie bună, pacienta se externează la 9 zile postoperator. La 6 luni postoperator probele serice AFP – în limite normale, fără semne imagistice de recidivă. Bisectionectomia centrală poate fi realizată atunci când tumora nu invadează pediculii vasculari aferenți parenchimului restant (secțiunea dreaptă posterioara / secțiunea stângă laterală) și presupune doua planuri de secțiune. Concluzii: Bisectionectomia centrală este operația de elecție pentru tumorile hepatice centrale prin care se prezervă cantitatea maxima de parenchim hepatic, minimalizându-se riscul de IHA postoperatorie. Este posibilă în cazuri atent selecționate și necesită experiență în rezecțiile hepatice majore.Introduction: By Brisbane terminology central bisectionectomy is the resection of segments 4a, 4b, 5, and 8 of the liver. Formerly called in different ways (mesohepatectomy, central hepatectomy, central lobectomy) central bisectionectomy is the elective surgery for liver tumors located in central segments (4a, 4b, 5 and 8), with better results than extensive liver resections (right / left trisectionectmy) because it minimizes the risk of postoperative liver failure. Case report: A 54 years old female, presented for right upper quadrant pain, weight loss (8 kg / 2 months); Blood tests: normal AFP; negative Ag Hbs, Ab Anti-HBc, Ab Anti-HCV. UGE/LGE – with a normal aspect; CT scan revealed centrally located liver tumor (segments 4a, 4b, 5, and 8) that includes MHV, away from the portal vein bifurcation. We performed a regulated central bisectionectomy with ligation of vascular pedicles for right anterior section (seg. 5 and 8) and those for left medial section (seg 4a and 4b). With good postoperative course, the patient was discharged in the 9th postoperative day. Six months postoperatively, the patient is good, without tumor relapse signs. Central bisectionectomy can not be performed when the tumor invades the vascular pedicles afferent to remaining parenchyma and requires two planes of transection. Conclusions: Central bisectionectomy is the best choice surgery for centrally located liver tumors which preserves the maximum amount of liver parenchyma thus minimizing the risk of postoperative liver failure

    Glomerular filtration rate in patients with atrial fibrillation and 1-year outcomes

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    We assessed 1-year outcomes in patients with atrial fibrillation enrolled in the EurObservational Research Programme AF General Pilot Registry (EORP-AF), in relation to kidney function, as assessed by glomerular filtration rate (eGFR). In a cohort of 2398 patients (median age 69 years; 61% male), eGFR (ml/min/1.73 m(2)) calculated using the CKD-EPI formula was ≥80 in 35.1%, 50-79 in 47.2%, 30-49 in 13.9% and <30 in 3.7% of patients. In a logistic regression analysis, eGFR category was an independent predictor of stroke/TIA or death, with elevated odds ratios associated with severe to mild renal impairment, ie. eGFR < 30 ml/min/1.73 m(2) [OR 3.641, 95% CI 1.572-8.433, p < 0.0001], 30-49 ml/min/1.73 m(2) [OR 3.303, 95% CI 1.740-6.270, p = 0.0026] or 50-79 ml/min/1.73 m2 [OR 2.094, 95% CI 1.194-3.672, p = 0.0003]. The discriminant capability for the risk of death was tested among various eGFR calculation algorithms: the best was the Cockcroft-Gault equation adjusted for BSA, followed by Cockcroft-Gault equation, and CKD-EPI equation, while the worst was the MDRD equation. In conclusion in this prospective observational registry, renal function was a major determinant of adverse outcomes at 1 year, and even mild or moderate renal impairments were associated with an increased risk of stroke/TIA/death

    Glomerular filtration rate in patients with atrial fibrillation and 1-year outcomes

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    We assessed 1-year outcomes in patients with atrial fibrillation enrolled in the EurObservational Research Programme AF General Pilot Registry (EORP-AF), in relation to kidney function, as assessed by glomerular filtration rate (eGFR). In a cohort of 2398 patients (median age 69 years; 61% male), eGFR (ml/min/1.73\u2009m(2)) calculated using the CKD-EPI formula was 6580 in 35.1%, 50-79 in 47.2%, 30-49 in 13.9% and <30 in 3.7% of patients. In a logistic regression analysis, eGFR category was an independent predictor of stroke/TIA or death, with elevated odds ratios associated with severe to mild renal impairment, ie. eGFR\u2009<\u200930\u2009ml/min/1.73\u2009m(2) [OR 3.641, 95% CI 1.572-8.433, p\u2009<\u20090.0001], 30-49\u2009ml/min/1.73\u2009m(2) [OR 3.303, 95% CI 1.740-6.270, p\u2009=\u20090.0026] or 50-79\u2009ml/min/1.73\u2009m2 [OR 2.094, 95% CI 1.194-3.672, p\u2009=\u20090.0003]. The discriminant capability for the risk of death was tested among various eGFR calculation algorithms: the best was the Cockcroft-Gault equation adjusted for BSA, followed by Cockcroft-Gault equation, and CKD-EPI equation, while the worst was the MDRD equation. In conclusion in this prospective observational registry, renal function was a major determinant of adverse outcomes at 1 year, and even mild or moderate renal impairments were associated with an increased risk of stroke/TIA/death

    Telocytes and putative stem cells in the lungs: electron microscopy, electron tomography and laser scanning microscopy

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    This study describes a novel type of interstitial (stromal) cell — telocytes (TCs) — in the human and mouse respiratory tree (terminal and respiratory bronchioles, as well as alveolar ducts). TCs have recently been described in pleura, epicardium, myocardium, endocardium, intestine, uterus, pancreas, mammary gland, etc. (see www.telocytes.com). TCs are cells with specific prolongations called telopodes (Tp), frequently two to three per cell. Tp are very long prolongations (tens up to hundreds of μm) built of alternating thin segments known as podomers (≤ 200 nm, below the resolving power of light microscope) and dilated segments called podoms, which accommodate mitochondria, rough endoplasmic reticulum and caveolae. Tp ramify dichotomously, making a 3-dimensional network with complex homo- and heterocellular junctions. Confocal microscopy reveals that TCs are c-kit- and CD34-positive. Tp release shed vesicles or exosomes, sending macromolecular signals to neighboring cells and eventually modifying their transcriptional activity. At bronchoalveolar junctions, TCs have been observed in close association with putative stem cells (SCs) in the subepithelial stroma. SCs are recognized by their ultrastructure and Sca-1 positivity. Tp surround SCs, forming complex TC-SC niches (TC-SCNs). Electron tomography allows the identification of bridging nanostructures, which connect Tp with SCs. In conclusion, this study shows the presence of TCs in lungs and identifies a TC-SC tandem in subepithelial niches of the bronchiolar tree. In TC-SCNs, the synergy of TCs and SCs may be based on nanocontacts and shed vesicles

    Biochemical properties of Paracoccus denitrificans FnrP:Reactions with molecular oxygen and nitric oxide

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    In Paracoccus denitrificans, three CRP/FNR family regulatory proteins, NarR, NnrR and FnrP, control the switch between aerobic and anaerobic (denitrification) respiration. FnrP is a [4Fe-4S] cluster containing homologue of the archetypal O2 sensor FNR from E. coli and accordingly regulates genes encoding aerobic and anaerobic respiratory enzymes in response to O2, and also NO, availability. Here we show that FnrP undergoes O2-driven [4Fe-4S] to [2Fe-2S] cluster conversion that involves up to 2 O2 per cluster, with significant oxidation of released cluster sulfide to sulfane observed at higher O2 concentrations. The rate of the cluster reaction was found to be ~6-fold lower than that of E. coli FNR, suggesting that FnrP can remain transcriptionally active under microaerobic conditions. This is consistent with a role for FnrP in activating expression of the high O2 affinity cytochrome c oxidase under microaerobic conditions. Cluster conversion resulted in dissociation of the transcriptionally active FnrP dimer into monomers. Therefore, along with E. coli FNR, FnrP belongs to the subset of FNR proteins in which cluster type is correlated with association state. Interestingly, two key charged residues, Arg140 and Asp154, that have been shown to play key roles in the monomer-dimer equilibrium in E. coli FNR are not conserved in FnrP, indicating that different protomer interactions are important for this equilibrium. Finally, the FnrP [4Fe-4S] cluster is shown to undergo reaction with multiple NO molecules, resulting in iron nitrosyl species and dissociation into monomers

    Neural Stem Cells Engineered to Express Three Therapeutic Factors Mediate Recovery from Chronic Stage CNS Autoimmunity

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    © The American Society of Gene and Cell Therapy. Treatment of chronic neurodegenerative diseases such as multiple sclerosis (MS) remains a major challenge. Here we genetically engineer neural stem cells (NSCs) to produce a triply therapeutic cocktail comprising IL-10, NT-3, and LINGO-1-Fc, thus simultaneously targeting all mechanisms underlie chronicity of MS in the central nervous system (CNS): persistent inflammation, loss of trophic support for oligodendrocytes and neurons, and accumulation of neuroregeneration inhibitors. After transplantation, NSCs migrated into the CNS inflamed foci and delivered these therapeutic molecules in situ. NSCs transduced with one, two, or none of these molecules had no or limited effect when injected at the chronic stage of experimental autoimmune encephalomyelitis; cocktail-producing NSCs, in contrast, mediated the most effective recovery through inducing M2 macrophages/microglia, reducing astrogliosis, and promoting axonal integrity and endogenous oligodendrocyte/neuron differentiation. These engineered NSCs simultaneously target major mechanisms underlying chronicity of multiple sclerosis (MS) and encephalomyelitis (EAE), thus representing a novel and potentially effective therapy for the chronic stage of MS, for which there is currently no treatment available

    Validation of epidemiological tools for eczema diagnosis in brazilian children: the isaac's and uk working party's criteria

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    BACKGROUND: Instruments for field diagnosis of eczema are increasingly used, and it is essential to understand specific limitations to make best use of their strengths. Our objective was to assess the validity of ISAAC and UK Working Party criteria for field diagnosis of eczema in children. METHODS: We performed a cohort study in urban Brazil. Parents/guardians of 1,419 children answered ISAAC phase II questionnaire. Children were examined for skin lesions (UKWP protocol). Two dermatologists examined most cases of eczema (according to ISAAC or UKWP), and a sample without eczema. RESULTS: Agreement between repeat questionnaires on the filter question was poor (kappa = 0.4). Agreement between the 2 dermatologists was fair (kappa = 0.6). False positive reports included scabies in 39% of ISAAC cases and 33% of UKWP cases. Sensitivity and PPV were low (ISAAC: 37.1% and 16.1%; UKWP: 28.6% and 23.8%). Specificity and NPV were high (ISAAC: 90.0% and 96.6%; UKWP: 95.3% and 96.2%). One-year prevalence of eczema was 11.3% (ISAAC), 5.9% (UKWP) and 4.9% (adjusted dermatologist diagnosis). Point prevalence of scabies (alone or not) was 43%, 33% and 18%, in eczemas according to ISAAC, to UKWP and to dermatologists. The reasons why children with eczema were not identified by ISAAC or UKWP were wrongly denying dry skin, itchy rash or personal history of atopic diseases. A limitation is that questionnaire was already validated in Brazil, but not field tested in this specific setting. CONCLUSIONS: Studies using UKWP or ISAAC criteria should include a validation arm, to contribute to the understanding of potential limitations of their use in different contexts and to explore solutions. We list specific recommendations

    X-ray emission from the Sombrero galaxy: discrete sources

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    We present a study of discrete X-ray sources in and around the bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival Chandra observations with a total exposure of ~200 ks. With a detection limit of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30 kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray binaries (LMXBs). We quantify the differential luminosity functions (LFs) for both the detected GC and field LMXBs, whose power-low indices (~1.1 for the GC-LF and ~1.6 for field-LF) are consistent with previous studies for elliptical galaxies. With precise sky positions of the GCs without a detected X-ray source, we further quantify, through a fluctuation analysis, the GC LF at fainter luminosities down to 1E35 erg/s. The derived index rules out a faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent findings in several elliptical galaxies and the bulge of M31. On the other hand, the 2-6 keV unresolved emission places a tight constraint on the field LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101 sources in the halo of Sombrero. The presence of these sources cannot be interpreted as galactic LMXBs whose spatial distribution empirically follows the starlight. Their number is also higher than the expected number of cosmic AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray surveys. We suggest that either the cosmic X-ray background is unusually high in the direction of Sombrero, or a distinct population of X-ray sources is present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns
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