Quantum tailoring of electronic properties in covalently functionalized graphene: application to ammonia gas detection.

Functionalized graphene offers great potential in the field of rapid detection of gases at room temperature. We performed first-principles calculations to study the suitability of 4-sulfobenzenediazonium salts (4SBD) as bandgap modifier in graphene. The signature of unpaired spins is evidenced near the Fermi level owing to the symmetry breaking of graphene sublattices. 4SBD-chemisorbed on graphene is found to be electronically sensitive to the presence of ammonia NH3 with increasing gas concentration.

Two-Yukawa fluid at a hard wall: Field theory treatment.

We apply a field-theoretical approach to study the structure and thermodynamics of a two-Yukawa fluid confined by a hard wall. We derive mean field equations allowing for numerical evaluation of the density profile which is compared to analytical estimations. Beyond the mean field approximation, analytical expressions for the free energy, the pressure, and the correlation function are derived. Subsequently, contributions to the density profile and the adsorption coefficient due to Gaussian fluctuations are found. Both the mean field and the fluctuation terms of the density profile are shown to satisfy the contact theorem. We further use the contact theorem to improve the Gaussian approximation for the density profile based on a better approximation for the bulk pressure. The results obtained are compared to computer simulation data.

Contact theorems for anisotropic fluids near a hard wall.

In this paper, from the Born-Green-Yvon equation, we formulate a general expression for the contact value of the singlet distribution function for anisotropic fluids near a hard wall. This expression consists of two separate contributions. One is related to the bulk partial pressure for a given orientation of the molecules. The second is related to the anchoring phenomena and is characterized by the direct interaction between the molecules and the wall. Given this relation, we formulate the contact theorems for the density and order parameter profiles. The results are illustrated by the case of a nematic fluid near a hard wall.

Spontaneous polarization of the neutral interface for valence asymmetric coulombic systems.

In this paper, we discuss the phenomenon of a spontaneous polarization of a neutral hard planar interface for valence asymmetric Coulombic systems. Within a field theoretical description, we account for the existence of nontrivial charge density and electric potential profiles. The analysis of the phenomenon shows that the effect is related to combinatorics in relation with the existence of the two independent species cations and anions. This simple and basic feature is related to the quantum mechanical properties of the system. The theoretical results are compared with numerical simulations data and are shown to be in very good agreement, which a fortiori justifies our physical interpretation.

On the contact conditions for the charge profile in the theory of the electrical double layer for nonsymmetrical electrolytes.

In this paper, we generalize a recently derived expression of the contact value of the charge profile for the case of nonsymmetrical electrolytes. For the electrolytes with a single type of cation and anion, this relation can be presented as the sum of three contributions. One of them is the normal component of the Maxwell electrostatic stress tensor. The second one is the surface electrostatic property, which is defined as the integral of the product of the gradient of the electrical potential and the density distribution function of coions. The third term is the bulk contribution, which is defined by the sum for anions and for cations of the product of their charge and their partial pressure. For noncharged surfaces, only the last two terms are present and have the same sign in the case of size asymmetry. In the case of charge asymmetry, the contact value of the charge profile is the result of the competitions of bulk and surface terms in which the bulk term is dominant. Using both the contact theorems for the density and the charge profiles, the exact expressions for the contact values of the profiles of coions and counterions are obtained and some related properties are discussed. A semiempirical expression of the contact value of the charge profile is discussed in relation to our exact result.

New results from the contact theorem for the charge profile for symmetric electrolytes.

In this paper the contact value of the charge profile at a charged interface is presented as the sum of the normal component of the Maxwell electrostatic tensor and a new electrostatic property defined by the integral from the product of the gradient of the electrical potential and the singlet distribution function of coions (ions with sign of the charge equal to that of the interface). On physical arguments, it is conjectured that this new property is a monotonic function of the electrical charge at the wall and is limited by the bulk electrolyte pressure for large electrical charges at the wall. Using the contact theorems for the density and the charge profiles, the exact expressions for the contact values of the profiles of coions and counterions are derived and some related general properties are discussed.

Contact conditions for the charge in the theory of the electrical double layer.

In this paper, from the Born-Green-Yvon equations of the liquid-state theory, we derive a general expression for the charge-density contact value at charged interfaces. This relation is discussed, in particular, for symmetrical electrolytes. We emphasize an essential coupling between the electric properties and the density profile. Limiting behavior at small and large charges at the interface is discussed.

Desorption transition at charged interfaces: theoretical approach and experimental evidence

A field theory is used to describe an ionic solution in contact with a charged and adsorbing wall. The Hamiltonian, a functional of the ionic density fields, contains the entropy, the electrostatic energy, a nonlocal Van der Waals type contribution preventing sharp density variations, and an adsorption potential. The mean-field equations are solved numerically. However, they can be recasted so as to put in evidence a one parameter Lie group structure, which is a generalization of the charge-translation symmetry present in the Gouy-Chapman theory. There is a region in the charge-adsorption parameter space where this symmetry is broken, which corresponds to a desorption transition for the ionic species. The properties of this transition are investigated. Finally, this desorption phenomenon provides a simple explanation for a general feature in the properties of metal-electrolyte interfaces: the branching pattern observed in the experimental capacitance curves for a series of electrolytes. The part of the capacitance curves which is independent of the nature of the ions is related to the absence of interaction of the ionic species with the wall once the desorption takes place.

Efficacy of amphotericin B colloidal dispersion in the treatment of Mediterranean visceral leishmaniasis in immunocompetent adult patients.

Twelve immunocompetent adults with Mediterranean visceral leishmaniasis (VL) were treated with amphotericin B colloidal dispersion (ABCD; 2 mg/kg/d for 7 d). All patients showed rapid clinical response without significant adverse events. Two weeks after therapy they were parasitologically cured and no relapses occurred during 6 months. ABCD is a valid alternative in the management of Mediterranean VL in adult patients.

Sp1 cooperates with the ets transcription factor, GABP, to activate the CD18 (beta2 leukocyte integrin) promoter.

CD18, the beta chain of the leukocyte integrins, plays a crucial role in immune and inflammatory responses. CD18 is expressed exclusively by leukocytes, and it is transcriptionally regulated during the differentiation of myeloid cells. The ets factors, PU.1 and GABP, bind to three ets sites in the CD18 promoter, which are essential for high level myeloid expression of CD18. We now identify two binding sites for the transcription factor, Sp1, that flank these ets sites. Sp1 is the only factor from myeloid cells that binds to these sites in a sequence-specific manner. Mutagenesis of these sites abrogates Sp1 binding and significantly reduces the activity of the transfected CD18 promoter in myeloid cells. Transfection of Sp1 into Drosophila Schneider cells, which otherwise lack Sp1, activates the CD18 promoter dramatically. GABP also activates the CD18 promoter in Schneider cells. Co-transfection of Sp1 and GABP activates CD18 more than the sum of their individual effects, indicating that these factors cooperate to transcriptionally activate myeloid expression of CD18. These studies support a model of high level, lineage-restricted gene expression mediated by cooperative interactions between widely expressed transcription factors.

Short-course treatment of visceral leishmaniasis with liposomal amphotericin B (AmBisome).

We evaluated liposomal amphotericin B (AmBisome; Vestar, San Dimas, CA) administered to 88 immunocompetent patients (56 children) with visceral leishmaniasis (VL) caused by Leishmania infantum. Thirteen patients received 4 mg/kg on days 1-5 and 10 (total dose, 24 mg/kg), and all were cured; 42 received 3 mg/kg on days 1-5 and 10 (18 mg/kg), and 41 were cured; 32 received 3 mg/kg on days 1-4 and 10 (15 mg/kg), and 29 were cured (amastigotes were not cleared from 1 child, and 2 relapsed). One adult was cured with a total dose of 12mg/kg. The four children who were not cured received 3 mg/kg for 10 days; none had further relapses. There were no significant adverse events. For VL due to L. infantum, we recommended a total dose of AmBisome of > or = 20 mg/kg, given in > or = 5 doses of 3-4 mg/kg over > or = 10 days.

GABP and PU.1 compete for binding, yet cooperate to increase CD18 (beta 2 leukocyte integrin) transcription.

CD18 (beta 2 leukocyte integrin) is a leukocyte-specific adhesion molecule that plays a crucial role in immune and inflammatory responses. A 79-nucleotide fragment of the CD18 promoter is sufficient to direct myeloid transcription. The CD18 promoter is bound by the B lymphocyte- and myeloid-restricted ets factor, PU.1, and disruption of the PU.1-binding sites significantly reduces promoter activity. However, PU.1 alone cannot fully account for the leukocyte-specific and myeloid-inducible transcription of CD18. We identified a ubiquitously expressed nuclear protein complex of extremely low electrophoretic mobility that also binds to this region of the CD18 promoter. This binding complex is a heterotetramer composed of GABP alpha, and ets factor, and GABP beta, a subunit with homology to Drosophila Notch. GABP alpha competes with the lineage restricted factor, PU.1, for the same critical CD18 ets sites. The CD18 promoter is activated in myeloid cells by transfection with both GABP alpha and GABP beta together, but not by either factor alone. Transfection of non-hematopoietic cells with the two GABP subunits together with PU.1 is sufficient to activate CD18 transcription in otherwise non-permissive cells. Thus, GABP and PU.1 compete for the same binding sites but cooperate to activate CD18 transcription.

Differential regulation of JunD by dihydroxycholecalciferol in human chronic myelogenous leukemia cells.

1,25-Dihydroxyvitamin D3 inhibits the proliferation of the chronic myelogenous leukemia cell line RWLeu-4 but not the resistant variant, JMRD3. Although these cells exhibit no detectable differences in the vitamin D receptor, alterations in the interaction of nuclear extracts with the osteocalcin-1,25-dihydroxyvitamin D3-response element are noted. It is shown herein that the 1,25-dihydroxyvitamin D3 receptor binds to the osteocalcin-1,25-dihydroxyvitamin D3-response element along with activator protein-1 (AP-1) complexes and that the DNA binding activities of members of the Jun and Fos proto-oncogene families, which make up the AP-1 transcription factor, are differentially regulated by 1,25-dihydroxyvitamin D3. It is shown that JunD DNA binding activity is enhanced by 1,25-dihydroxyvitamin D3 during cell cycle arrest in the sensitive cells but is decreased in the resistant cells. These results suggest that the level of JunD DNA binding activity may be a critical factor in the regulation of proliferation.

CD18 (beta 2 leukocyte integrin) promoter requires PU.1 transcription factor for myeloid activity.

Normal cellular differentiation is linked to tightly regulated gene transcription. However, the DNA elements and trans-acting factors that regulate transcription in myeloid cells are poorly defined. CD18, the beta chain of the leukocyte integrins, is transcriptionally regulated during myeloid differentiation. The CD18 promoter is active after transfection into myeloid cells. We demonstrate that a region of the CD18 promoter that contains two binding sites for the PU.1 transcription factor is required for activity in myeloid cells. These sites are bound by in vitro translated PU.1 and by PU.1 from myeloid nuclear extracts. Mutagenesis of these sites abrogates binding by PU.1 and substantially decreases promoter activity in myeloid cells. Thus, the leukocyte-specific transcription factor PU.1 is required for myeloid activity of CD18.

[Audiometric results of 81 ossiculoplasties after tympanoplasty with closed technique in chronic cholesteatomatous otitis]. / Résultats audiométriques de 81 ossiculoplasties après tympanoplastie en technique fermée pour otites chroniques cholestéatomateuses.

We report our functional results about 81 ossiculoplastys during tympanoplasty with closed technique in chronic cholesteatomatous otitis. We discuss our functional results and the post-operative assessment of the audiometric gain. Patients presented either cholesteatomatous otitis sequelea or any preliminary status (retraction pockets) with attical impairment.

[The attic. Anatomoclinical correlation]. / Attique. Corrélation anatomo-chirurgicale.

Among the hidden parts of the middle ear, the posterior part of the atrium undoubtedly raises the most interest of otologists. The attic is a frequent localization of cholesteatoma and retraction pouches. Its anatomy is not well known, especially the anterior and internal walls. This anatomic study, based on the dissection of 41 petrus bones was designed to determine the anatomic limits and describe the "noble structures" of this region in order to "guide" future surgical procedures.

[Recurrence of nasosinusal polyposis after ethmoidectomy by endonasal approach. Functional, endoscopic, x-ray tomographic aspects and surgical implications]. / Récidive de la polypose nasosinusienne après ethmoidectomie par voie endonasale. Aspects fonctionnels, endoscopiques, tomodensitométriques et implications chirurgicales.

Recurrent polyposis after 116 endonasal ethmoidectomies performed in 61 patients were investigated on the basis of functional, endoscopic and tomodensitometric data. The results of the endoscopic examinations revealed that the anterior ethmoid was involved most often (41%) with either a single localization or in combination with other sites in the sinuses. Functional rhinosinus symptomatology was satisfactory in most cases after a mean follow-up of 22 months, especially for nasal obstruction which was initially predominant (91%). Headaches, especially fronto-orbial localizations, clearly decreased after the operation but there was no correlation between the presence of headache after the operation and the recurrence of the polyposis. Computed tomography gave results similar to those obtained by endoscopy. However, a distinction could not be made between radio-opaque images of polyposis and certain cicatricial or inflammatory reactions. Unlike the functional outcome, ethmoidectomy had little effect on these images. Recurrent polyps appeared most often on the anterior ethmoid and the role of the initial infundibulotomy can be debated. It would appear that the prognosis of polyposis is not modified by extended anterior ethmoidectomy, suggesting that a more conservative surgical approach may be appropriate for frontal ethomoidal polyps.