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Aims: Circulating angiogenic cells (CAC) participate in cardiac repair. CAC recruitment to the ischaemic heart is mainly induced by the chemokine (C-X-C motif) receptor 4 (CXCR4)/stromal-cell derived factor-1α axis. However, CAC mobilization is only partly prevented by CXCR4 blockade, indicating that other mechanisms are involved. Since the expression of monocyte chemotactic protein 3 (MCP3) is increased in ischaemic hearts, we hypothesized that it may participate in CAC mobilization., Methods and Results: CAC were obtained from peripheral blood mononuclear cells of healthy volunteers. In vitro migration of CAC was concentration-dependently increased by recombinant MCP3 (one-fold increase, P= 0.001), and this effect was inhibited by antibodies neutralizing the chemokine (C-C motif) receptor 1 (CCR1). CCR1 expression at the surface of CAC was confirmed by flow cytometry. Conditioned medium from heparan sulfate-activated macrophages, which contained MCP3, induced the migration of CAC (one-fold increase, P= 0.01). This increase was partly inhibited by CCR1 antibodies. The migration of CAC was also stimulated by macrophage inflammatory protein 3β. This effect was blocked by CCR7 antibodies and was of lower magnitude than that of MCP3. MCP3 induced the formation of blood vessels in Matrigel plugs implanted in mice (1.5-fold increase, P< 0.001). This effect was abrogated by anti-CCR1 antibodies., Conclusion: This study shows that MCP3 stimulates the migration of CAC and angiogenesis, suggesting that MCP3 may be useful to improve cardiac repair.

We use numerical simulations to analyze recent experimental measurements of short-channel carbon nanotube field-effect transistors with palladium contacts. We show that the gate strongly modulates the contact properties, an effect that is distinct from that observed in Schottky barrier carbon nanotube transistors. This modulation of the contacts by the gate allows for the realization of superior subthreshold swings for short channels, and improved scaling behavior. These results further elucidate the behavior of carbon nanotube-metal contacts, and should be useful in the optimization of high-performance carbon nanotube electronics.

Objective: To evaluate the expression of innate immunity markers at the site of nodules caused by hidradenitis suppurativa (HS)., Design: Prospective analysis of 12 patients with HS., Setting: Unité de Cancéro-Dermatologie, Nantes Hospital, Nantes; Service de Dermatologie, Poitiers Hospital, Poitiers; and Service de Dermatologie, Clinique de Courlancy, Reims, France, Patients: Twelve patients (Hurley stage I or II) in whom the disease had progressed for at least 6 months and who had a minimum of 2 closed nodules in typical sites., Main Outcome Measures: Two biopsies were performed at baseline: one in a closed inflammatory nodule and one in healthy adjoining skin. Patients were treated for 3 months with zinc gluconate at a dosage of 90 mg/d. A new biopsy was then performed in the same nodule. Innate immunity markers (toll-like receptors 2, 3, 4, 7, and 9; intercellular adhesion molecule 1; interleukin [IL] 6 and 10; tumor necrosis factor; α melanocyte stimulating hormone; transforming growth factor β; β-defensin 2 and 4; and insulinlike growth factor 1) were studied by immunohistochemical analysis., Results: We observed significantly decreased expression (P < .001) of all the innate immunity markers studied except IL-10 in nonlesional and lesional HS skin. The downregulation of innate markers was significantly stronger in lesional HS skin compared with normal skin except for tumor necrosis factor. Three months of zinc treatment induced a significant increase in the expression of all the markers involved in innate immunity., Conclusion: Our study demonstrates for the first time, to our knowledge, that a deficiency of the main innate immunity markers in typical HS sites may explain the development of chronic inflammatory nodules in this disease.

Hydroa vacciniforme (HV) is a rare photodermatosis. Several therapies, with sometimes severe side effects, have been used in isolated cases. We report a case of refractory HV successfully treated with dietary fish oil rich in ω-3 polyunsaturated fatty acids., (© 2011 Wiley Periodicals, Inc.)

Existing models of electrical contacts are often inapplicable at the nanoscale because there are significant differences between nanostructures and bulk materials arising from unique geometries and electrostatics. In this Review, we discuss the physics and materials science of electrical contacts to carbon nanotubes, semiconductor nanowires and graphene, and outline the main research and development challenges in the field. We also include a case study of gold contacts to germanium nanowires to illustrate these concepts.

Recently, individual single-walled carbon nanotubes (SWNTs) functionalized with azo-benzene chromophores were shown to form a new class of hybrid nanomaterials for optoelectronics applications. Here we use a number of experimental and computational techniques to understand the binding, orientation, and nature of coupling between chromophores and the nanotubes, all of which are relevant to future optimization of these hybrid materials. We find that the binding energy between chromophores and nanotubes depends strongly on the type of tether that is used to bind the chromophores to the nanotubes. The pyrene tethers form a much stronger attachment to nanotubes compared to anthracene or benzene rings, resulting in more than 80% retention of bound chromophores post-processing. Density functional theory (DFT) calculations show that the binding energy of the chromophores to the nanotubes is maximized for chromophores parallel to the nanotube sidewall, even with the use of tethers; optical second harmonic generation measurements show that there is nonetheless a partial radial orientation of the chromophores on the nanotubes. We find weak electronic coupling between the chromophores and the SWNTs, consistent with noncovalent binding. This weak coupling is still sufficient to quench the chromophore fluorescence through a combination of static and dynamic processes. Photoluminescence measurements show a lack of significant energy transfer from the chromophores to isolated semiconducting nanotubes.

The electronic properties of heterojunction electron gases formed in GaN/AlGaN core/shell nanowires with hexagonal and triangular cross sections are studied theoretically. We show that at nanoscale dimensions, the nonpolar hexagonal system exhibits degenerate quasi-one-dimensional electron gases at the hexagon corners, which transition to a core-centered electron gas at lower doping. In contrast, polar triangular core/shell nanowires show either a nondegenerate electron gas on the polar face or a single quasi-one-dimensional electron gas at the corner opposite the polar face, depending on the termination of the polar face. More generally, our results indicate that electron gases in closed nanoscale systems are qualitatively different from their bulk counterparts.

Photovoltaic devices using GaAs nanopillar radial p-n junctions are demonstrated by means of catalyst-free selective-area metal-organic chemical vapor deposition. Dense, large-area, lithographically defined vertical arrays of nanowires with uniform spacing and dimensions allow for power conversion efficiencies for this material system of 2.54% (AM 1.5 G) and high rectification ratio of 213 (at ±1 V). The absence of metal catalyst contamination results in leakage currents of ∼236 nA at -1 V. High-resolution scanning photocurrent microscopy measurements reveal the independent functioning of each nanowire in the array with an individual peak photocurrent of ∼1 nA at 544 nm. External quantum efficiency shows that the photocarrier extraction highly depends on the degenerately doped transparent contact oxide. Two different top electrode schemes are adopted and characterized in terms of Hall, sheet resistance, and optical transmittance measurements.

Background: We investigated an algorithmic approach to modelling angiogenesis controlled by vascular endothelial growth factor (VEGF), the anti-angiogenic soluble VEGF receptor 1 (sVEGFR-1) and adenosine (Ado). We explored its feasibility to test angiogenesis-relevant hypotheses. We illustrated its potential to investigate the role of Ado as an angiogenesis modulator by enhancing VEGF activity and antagonizing sVEGFR-1., Results: We implemented an algorithmic model of angiogenesis consisting of the dynamic interaction of endothelial cells, VEGF, sVEGFR-1 and Ado entities. The model is based on a logic rule-based methodology in which the local behaviour of the cells and molecules is encoded using if-then rules. The model shows how Ado may enhance angiogenesis through activating and inhibiting effects on VEGF and sVEGFR-1 respectively. Despite the relative simplicity of the model, it recapitulated basic features observed in in vitro models. However, observed disagreements between our models and in vitro data suggest possible knowledge gaps and may guide future experimental directions., Conclusions: The proposed model can support the exploration of hypotheses about the role of different molecular entities and experimental conditions in angiogenesis. Future expansions can also be applied to assist research planning in this and other biomedical domains.

Background: Endothelial progenitor cells (EPCs) have been implicated in different processes crucial to vasculature repair, which may offer the basis for new therapeutic strategies in cardiovascular disease. Despite advances facilitated by functional genomics, there is a lack of systems-level understanding of treatment response mechanisms of EPCs. In this research we aimed to characterize the EPCs response to adenosine (Ado), a cardioprotective factor, based on the systems-level integration of gene expression data and prior functional knowledge. Specifically, we set out to identify novel biosignatures of Ado-treatment response in EPCs., Results: The predictive integration of gene expression data and standardized functional similarity information enabled us to identify new treatment response biosignatures. Gene expression data originated from Ado-treated and -untreated EPCs samples, and functional similarity was estimated with Gene Ontology (GO)-based similarity information. These information sources enabled us to implement and evaluate an integrated prediction approach based on the concept of k-nearest neighbours learning (kNN). The method can be executed by expert- and data-driven input queries to guide the search for biologically meaningful biosignatures. The resulting integrated kNN system identified new candidate EPC biosignatures that can offer high classification performance (areas under the operating characteristic curve>0.8). We also showed that the proposed models can outperform those discovered by standard gene expression analysis. Furthermore, we report an initial independent in vitro experimental follow-up, which provides additional evidence of the potential validity of the top biosignature., Conclusion: Response to Ado treatment in EPCs can be accurately characterized with a new method based on the combination of gene co-expression data and GO-based similarity information. It also exploits the incorporation of human expert-driven queries as a strategy to guide the automated search for candidate biosignatures. The proposed biosignature improves the systems-level characterization of EPCs. The new integrative predictive modeling approach can also be applied to other phenotype characterization or biomarker discovery problems.

We present electronic transport measurements of GaAs nanowires grown by catalyst-free metal-organic chemical vapor deposition. Despite the nanowires being doped with a relatively high concentration of substitutional impurities, we find them inordinately resistive. By measuring sufficiently high aspect ratio nanowires individually in situ, we decouple the role of the contacts and show that this semi-insulating electrical behavior is the result of trap-mediated carrier transport. We observe Poole-Frenkel transport that crosses over to phonon-assisted tunneling at higher fields, with a tunneling time found to depend predominantly on fundamental physical constants as predicted by theory. By using in situ electron beam irradiation of individual nanowires, we probe the nanowire electronic transport when free carriers are made available, thus revealing the nature of the contacts.

Doping of semiconductors is essential in modern electronic and photonic devices. While doping is well understood in bulk semiconductors, the advent of carbon nanotubes and nanowires for nanoelectronic and nanophotonic applications raises some key questions about the role and impact of doping at low dimensionality. Here we show that for semiconducting carbon nanotubes, band gaps and exciton binding energies can be dramatically reduced upon experimentally relevant doping, and can be tuned gradually over a broad range of energies in contrast with higher dimensional systems. The latter feature is made possible by a novel mechanism involving strong dynamical screening effects mediated by acoustic plasmons.

It is known from animal models that the cardioprotective nucleoside adenosine stimulates angiogenesis mainly through up-regulation of vascular endothelial growth factor (VEGF). Since macrophages infiltrate the heart after infarction and because adenosine receptors behave differently across species, we evaluated the effect of adenosine on VEGF in human macrophages. Adenosine dose-dependently up-regulated VEGF expression and secretion by macrophages from healthy volunteers. VEGF production was also increased by blockade of extracellular adenosine uptake with dipyridamole. This effect was exacerbated by the toll-like receptor-4 ligands heparan sulfate, hyaluronic acid and lipopolysaccharide, and was associated with an increase of hypoxia inducible factor-1alpha expression, the main transcriptional inducer of VEGF in hypoxic conditions. The agonist of the adenosine A2A receptor CGS21680 reproduced the increase of VEGF and the antagonist SCH58261 blunted it. In conclusion, these results provide evidence that activation of adenosine A2A receptor stimulates VEGF production in human macrophages. This study suggests that adenosine is a unique pro-angiogenic molecule that may be used to stimulate cardiac repair.

We present an approach for time-dependent quantum transport based on a self-consistent nonequilibrium Green function formalism. The technique is applied to a ballistic carbon nanotube transistor in the presence of a time-harmonic signal at the gate. In the on state, the dynamic conductance exhibits plasmonic resonant peaks at terahertz frequencies. These vanish in the off state, and the dynamic conductance displays smooth oscillations, a signature of single-particle quantum effects. We show that the nanotube kinetic inductance plays an essential role in the high-frequency behavior.

We present electronic transport measurements in individual Au-catalyst/Ge-nanowire interfaces demonstrating the presence of a Schottky barrier. Surprisingly, the small-bias conductance density increases with decreasing diameter. Theoretical calculations suggest that this effect arises because electron-hole recombination in the depletion region is the dominant charge transport mechanism, with a diameter dependence of both the depletion width and the electron-hole recombination time. The recombination time is dominated by surface contributions and depends linearly on the nanowire diameter.

We present a nanoscale color detector based on a single-walled carbon nanotube functionalized with azobenzene chromophores, where the chromophores serve as photoabsorbers and the nanotube as the electronic read-out. By synthesizing chromophores with specific absorption windows in the visible spectrum and anchoring them to the nanotube surface, we demonstrate the controlled detection of visible light of low intensity in narrow ranges of wavelengths. Our measurements suggest that upon photoabsorption, the chromophores isomerize from the ground state trans configuration to the excited state cis configuration, accompanied by a large change in dipole moment, changing the electrostatic environment of the nanotube. All-electron ab initio calculations are used to study the chromophore-nanotube hybrids and show that the chromophores bind strongly to the nanotubes without disturbing the electronic structure of either species. Calculated values of the dipole moments support the notion of dipole changes as the optical detection mechanism.

We aimed to better characterize exceptional cases of long survivors (LSs) among patients with stage IV melanoma. We performed a comprehensive regional investigation in the Champagne-Ardenne region, France. During the period 1994-2003, 316 patients died of melanoma whereas 10 patients diagnosed with distant metastases had a subsequent survival time > 4 years. These 10 LSs were characterized by a long delay (median: 58 months) prior to distant metastases and by frequent subsequent complete remissions (CRs). Eighteen episodes of CRs, lasting 3-139 months (mean: 26.4), were documented in 9 patients, for single or multiple tumors, for metastases of any site and with any treatment, even including spontaneous CRs. Four of 8 evaluable patients had clinical and/or biological features of auto-immunity. At 31 March 2007, 3 patients had died of melanoma and 1 of a chemo-induced leukaemia. The median survival time was 65 months (range: 52-139). These data suggest that long survival in stage IV melanoma might depend less on the site of metastases and specific therapies than on the patients themselves and their spontaneous antitumor control.

In the title compound, C(27)H(17)N(3)O(4), the azo group displays a trans conformation and the dihedral angles between the central benzene ring and the pendant anthracene and nitro-benzene rings are 82.94 (7) and 7.30 (9)°, respectively. In the crystal structure, weak C-H⋯O hydrogen bonds, likely associated with a dipole moment present on the mol-ecule, help to consolidate the packing.

Aims: Matrix metalloproteinase-9 (MMP-9) plays an important role in ventricular remodelling after acute myocardial infarction (MI). The cardioprotectant adenosine (Ado) may be involved in ventricular remodelling. We have shown that Ado inhibits the secretion of MMP-9 by human neutrophils. This study investigated the effect of Ado on MMP-9 production by human macrophages., Methods and Results: Cells used in this study were monocytes of healthy volunteers, a human monocyte cell line, and leukocytes from patients following MI. Monocytes were differentiated into macrophages and treated with Ado. Ado enhanced MMP-9 secretion by human macrophages in a time- and dose-dependent manner. Increasing the level of endogenous Ado by inhibition of Ado deaminase or Ado transferase also increased MMP-9 secretion. Ado enhanced MMP-9 production when macrophages were activated by hypoxia or Toll-like receptor-4 ligands such as lipopolysaccharide, hyaluronan, and heparan sulfate. The effect of Ado was replicated by the A3 agonist IB-MECA and inhibited by silencing the A3 receptor. Ado improved monocyte capacity to migrate through a matrix of gelatin B, and this effect was blocked by inhibition of MMP-9 activity. The chemotactic capacity of macrophages was reduced by Ado through a loss of expression of the monocyte chemotactic protein-1 receptor. Finally, MMP-9 expression was higher in blood cells from patients with acute MI compared with healthy volunteers., Conclusion: Adenosine activates MMP-9 secretion by macrophages through its A3 receptor. The effect is in contrast to that observed in neutrophils, where Ado inhibits MMP-9 secretion by the A2a receptor. These observations may have important implications for therapeutic strategies targeting Ado receptors in the setting of MI.

The current-voltage characteristics of thin wires are often observed to be nonlinear, and this behavior has been ascribed to Schottky barriers at the contacts. We present electronic transport measurements on GaN nanorods and demonstrate that the nonlinear behavior originates instead from space-charge-limited current. A theory of space-charge-limited current in thin wires corroborates the experiments and shows that poor screening in high-aspect ratio materials leads to a dramatic enhancement of space-charge limited current, resulting in new scaling in terms of the aspect ratio.

We observe using low-energy electron microscopy the self-assembly of monolayer-thick stripes of Au on W(110) near the transition temperature between stripes and the nonpatterned (homogeneous) phase. We demonstrate that the amplitude of this Au-stripe phase decreases with increasing temperature and vanishes at the order-disorder transition (ODT). The wavelength varies much more slowly with temperature and coverage than theories of stress-domain patterns with sharp boundaries would predict, and maintains a finite value of about 100 nm at the ODT. We argue that such nanometer-scale stripes should often appear near the ODT.

Objective: We sought to identify criteria able to distinguish between Jessner's lymphocytic infiltration of the skin (JLIS) and lupus erythematosus tumidus (LET)., Methods: The following characteristics were recorded in a retrospective, multicenter analysis of patients with JLIS and LET: clinical features (number, size, type, and localization of lesions; photosensitivity; extracutaneous signs), histologic findings, phototesting, lupus serology, treatment, and outcome. Available histologic slides were reviewed blinded to the initial diagnosis using a pre-established grid., Results: Univariate analysis of data from patients with JLIS (15 women, 17 men; mean age: 35 years) and LET (13 women, one man; mean age: 31 years) showed the following significant (P < .05) differences: more frequent back involvement and annular lesions in JLIS, as opposed to female predominance, more frequent face involvement, and plaques in LET. Phototesting, especially ultraviolet B, induced lesions in 18 of 26 patients with JLIS and all 4 with LET. The blinded histologic review (33 samples) only found slight epidermal atrophy and focal thickened dermoepidermal junction more frequent and perivascular lymphocyte infiltrations less dense in LET. The two groups of patients reclassified according histopathologic features (18 LET and 11 JLIS) showed only slight clinical differences (more frequent nasal bridge lesions in LET and annular lesions in JLIS)., Limitation: The retrospective nature of the study is a limitation., Conclusion: JLIS and LET in this population showed more similarities than differences, supporting a continuous spectrum covering these two entities.

Background: The aim of this study was to evaluate the risk of ureteral injuries and to discuss how to avoid their occurence after laparoscopic hysterectomy indicated for benign uterine pathologies., Methods: This observational study covers the period from January 1993 to December 2005 (retrospective study from 1993 to 2000 and prospective from 2001). We reviewed incidence, methods of diagnosis and management of ureteral injuries., Results: The rate of ureteral injuries was 0.3% (four patients). Three patients presented a ureteral fistula diagnosed secondarily some time after the operation. The fourth patient presented a ureteral injury that was diagnosed peroperatively. Three out of four of the lesions were observed on the right side. In every case, there were preoperative risk factors connected with a past history of surgery, or the lateral location of uterine myomas. All four patients needed ureterovesical reimplantation. The outcome was good in all four cases., Conclusions: The rate of ureter complications after laparoscopic hysterectomy is low and comparable to that observed after hysterectomy by laparotomy. The risk should not prevent laparoscopic hysterectomy being used more widely. Prevention depends on training in the technique and the surgeon's experience.

We present a theory for size-dependent shapes of Pb nanoprecipitates in Al, introducing the concept of "magic shapes," i.e., shapes having near-zero homogeneous elastic strains. Our quantitative atomistic calculations of edge energies show their effect on precipitate shape to be negligible, thus it appears that shapes must be due to the combined effect of strain and interface energies. By employing an algorithm for generating magic shapes, we replicate the experimental observations by selecting magic-shape precipitates with interfacial energies less than a cutoff value.

We demonstrate an optically active nanotube-hybrid material by functionalizing single-wall nanotubes with an azo-based chromophore. Upon UV illumination, the conjugated chromophore undergoes a cis-trans isomerization leading to a charge redistribution near the nanotube. This charge redistribution changes the local electrostatic environment, shifting the threshold voltage and increasing the conductivity of the nanotube transistor. For a approximately 1%-2% coverage, we measure a shift in the threshold voltage of up to 1.2 V. Further, the conductance change is reversible and repeatable over long periods of time, indicating that the chromophore-functionalized nanotubes are useful for integrated nanophotodetectors.

We present self-consistent, non-equilibrium Green's function calculations of the characteristics of short channel carbon nanotube transistors, focusing on the regime of ballistic transport with ohmic contacts. We first establish that the band line-up at the contacts is renormalized by charge transfer, leading to Schottky contacts for small diameter nanotubes and ohmic contacts for large diameter nanotubes, in agreement with recent experiments. For short channel ohmic contact devices, source-drain tunnelling and drain-induced barrier lowering significantly impact the current-voltage characteristics. Furthermore, the ON state conductance shows a temperature dependence, even in the absence of phonon scattering or Schottky barriers. This last result also agrees with recently reported experimental measurements.

Objective: Sentinel node (SN) identification in vulvar carcinoma would avoid groin dissection and its complications in early stages, but we first have to validate the method, as an unrecognised node metastasis is detrimental to survival., Patients and Methods: Since June 2002, 38 patients with T1 or T2 lesions underwent SN identification by radioactive tracer injection and scintigraphy with, on the following day, per operative use of a handheld probe +/- patent blue dye. In case of a midline lesion, a bilateral inguinal dissection was performed whatever the result of SN identification. SN free from disease were ultrastaged with immunohistochemistry., Results: 1 or more SN were identified in 36 out of 38 patients. 64 groins were analysed, 15 with node metastases. In 9 out of these 15 cases the SN was metastatic, in 5 it had not been identified, and in 1 it was a false negative. In these last 6 cases, there were massively metastatic nodes in the groin. In 19 out of the 26 midline lesions the surgeon identified only unilateral SN. The side without SN contained metastatic nodes in 5 cases., Discussion and Conclusion: Failure in SN identification is sometimes related to a massively invaded node. This should be taken into account especially in the management of midline tumors where a seemingly unilateral drainage at scintigraphy warrants nevertheless a surgical assessment of the mute groin.

Metal-semiconductor contacts play a key role in electronics. Here we show that for quasi-one-dimensional (Q1D) structures such as nanotubes and nanowires, side contact with the metal only leads to weak band realignment, in contrast with bulk metal-semiconductor contacts. Schottky barriers are much reduced compared with the bulk limit, and should facilitate the formation of good contacts. However, the conventional strategy of heavily doping the semiconductor to obtain Ohmic contacts breaks down as the nanowire diameter is reduced. The issue of Fermi level pinning is also discussed, and it is demonstrated that the unique density of states of Q1D structures makes them less sensitive to this effect. Our results agree with recent experimental work, and should apply to a broad range of Q1D materials.

We present nanometer-scale resolution, ballistic electron emission microscopy (BEEM) studies of Au/octanedithiol/n-GaAs (001) diodes. The presence of the molecule dramatically increases the BEEM threshold voltage and displays an unusual transport signature as compared to reference Au/GaAs diodes. Furthermore, BEEM images indicate laterally inhomogeneous interfacial structure. We present calculations that address the role of the molecular layer at the interface. Our results indicate that spatially resolved measurements add new insight to studies using conventional spatial-averaging techniques.

We present theoretical performance estimates for nanotube optoelectronic devices under bias. Current-voltage characteristics of illuminated nanotube p-n junctions are calculated using a self-consistent nonequilibrium Green's function approach. Energy conversion rates reaching tens of percent are predicted for incident photon energies near the band gap energy. In addition, the energy conversion rate increases as the diameter of the nanotube is reduced, even though the quantum efficiency shows little dependence on nanotube radius. These results indicate that the quantum efficiency is not a limiting factor for use of nanotubes in optoelectronics.

We present a combined experimental and theoretical analysis of the structure of finite-sized Sigma 3 [112] grain boundaries in Au. High-resolution electron microscopy shows lattice translations at the grain boundary, with the magnitude of the translation varying along the finite-sized grain boundaries. The presence of this structural profile is explained using continuum elasticity theory and first-principles calculations as originating from a competition between elastic energy and the energy cost of forming continuous [111] planes across the boundary. This competition leads to a structural transition between offset-free and nontrivial grain boundary structures at a critical grain boundary size, in agreement with the experiments. We also provide a method to estimate the energy barrier of the gamma surface.

Photocurrents in nanotube p-n junctions are calculated using a nonequilibrium Green function quantum transport formalism. The short-circuit photocurrent displays band-to-band transitions and photon-assisted tunneling, and has multiple sharp peaks in the infrared, visible, and ultraviolet. The operation of such devices in the nanoscale regime leads to unusual size effects, where the photocurrent scales linearly and oscillates with device length. The oscillations can be related to the density of states in the valence band, a factor that also determines the relative magnitude of the photoresponse for different bands.

Uniform finite facets are frequently observed at grain boundaries (GBs) and are usually attributed to equilibrium stabilization by GB stress. We report calculations for an aluminum twin GB using density functional theory, the embedded-atom method, and continuum elasticity theory. These methods show that GB stress is much too small to stabilize finite facets, suggesting that the usual explanation is incorrect.

Calculations of quantum transport in a carbon nanotube transistor show that such a device offers unique functionality. It can operate as a ballistic field-effect transistor, with excellent characteristics even when scaled to 10 nm dimensions. At larger gate voltages, channel inversion leads to resonant tunneling through an electrostatically defined nanoscale quantum dot. Thus the transistor becomes a gated resonant-tunneling device, with negative differential resistance at a tunable threshold. For the dimensions considered here, the device operates in the Coulomb blockade regime, even at room temperature.

Introduction: Cryosurgery is a well-established therapeutic modality for basal cell carcinoma. We report herein an important series of basal cell carcinoma treated by cryosurgery, with a five year cure rate evaluation., Patients and Method: Retrospective study with 395 basal cell carcinomas (over 358 patients - sex ratio H/F: 0.85) treated by cryosurgery between 1981 and 1992. For each patient the data were: age, sex, size of the lesion, location, clinical sub-type, tissue-temperature monitoring, recurrence date and esthetic outcome., Result: The lesions were located on the face (93 p. 100) and back (7 p. 100). Mean size was 17 mm. Clinical sub-types were known for 178 lesions; 11 p. 100 of BCC were morpheaform. Tissue-temperature monitoring was performed for 55 p. 100 of cases. 111 tumors were observed for more than 5 years. The 5-year actuarial failure rate was 9 p. 100. The 5-year cure rate was not significantly altered by sex, size of lesions, location and clinical sub-type. No frequent recurrences were observed when tissue-temperature monitoring had not been performed. Complications were rare and esthetic outcome was good., Discussion: The 5-year actuarial recurrence rate with cryosurgery is similar to conventional surgery. It is not essential to control tissue-temperature for preventing recurrences. Cryosurgery is a reliable treatment and outcome depends on surgeon experience. Quickness and low cost of this procedure argue for choosing cryosurgery when treating elderly patients.

Gynaecological laparoscopy is associated with a patient morbidity rate. Half of the complications occur during the installation stage.

We have developed a photodensitometry method to evaluate the intensity of cutaneous erythema objectively. The method measures the optical density of photographic slides of cutaneous erythema. It combines techniques used commonly but separately by investigators: diffuse transmittance spectroscopy (which is a variant of diffuse reflectance spectroscopy) and photography. We have used this method to study photosensitivity in 22 volunteers who received increasing doses of ultraviolet radiation to the back. Our work confirms the usefulness of an important parameter in photobiology: the regression slope of the curve representing the erythema index, a function of the logarithm of the dose applied.

A total of 67 patients, including 44 continent patients and 23 patients suffering from stress incontinence, underwent color Doppler examination of the urethra. The maximal urethral pressure and the amplitude of the urethral pulse were measured in 35 of the patients. Linear endovaginal sonography was performed in 25 of the patients to define the position of the urethrovesical unit at rest. The submucous vascular sheath was clearly visible. Its average thickness was 3.42 mm and its average length was 11.75 mm. The measurement reproducibility was good. The dimensions of the submucous vascular plexus and its pulsatility decreased with age and increased with maximal urethral pressure and the manometric amplitude of the urethral pulse. By coupling the sonographic data obtained with color Doppler and linear endovaginal sonography in 25 patients, we obtained a good estimate of the urethral pressure in 83% of the cases and could correctly diagnose all cases of continence in our series (n = 9) and 15 of 16 stress-incontinent patients.

Medicinal photoprotection is indicated in photosensitive skin diseases and photodermatoses. Vitamin PP and para-aminobenzoic acid can be tried in benign estival polymorphous light eruptions. Carotinoids are efficient in erythropoietic protoporphyria and useful in idiopathic polymorphous light eruptions and in remanent photosensitization. Immunodepressants may be used against remanent photosensitization.

Vitamin A acid has been used for 20 years in the local treatment of acne. In 1986, Kligman published a description of the efficacy of this molecule against skin ageing. In 1987, we began a study which is still in progress. It is intended to confirm the beneficial effects already observed in photosenescence and to demonstrate them by non-invasive methods and by standardized photographs. This study was randomized and carried out under double blind. Each patient acted as her own control. The concentration administered was 0.025 per cent for 6 months and then 0.05 per cent. The patient was followed up every month for 6 months and then every 4 months. The results demonstrated a reduction in the number and depth of the wrinkles and a regression of the pigmented spots. Safety was excellent and all the patients were highly satisfied with the treatment.

Sixteen patients with localized scleroderma (LS) and 11 with progressive systemic sclerosis (PSS) were studied using non-invasive techniques to determine skin thickness, skin extensibility, transcutaneous PO2 and cutaneous blood flow and were compared with normal controls. LS was characterized by a decreased skin extensibility with thickening of the skin in progressive lesions. There was an increase in the cutaneous microcirculation with a decrease in the PO2. In PSS, there was a decrease in the skin extensibility caused by thickening of the skin, but no change in cutaneous microcirculation or PO2 values. These results indicate that skin thickness and extensibility are the most useful parameters in the study of the progression of LS and PSS.

Six adult volunteers were given 1 g/d of intravenous ceftriaxone for 5 d (consecutive). Ceftriaxone and beta-lactamase activities were assayed in fecal samples obtained before and during drug administration, and anaerobic bacteria, Enterobacteriaceae, and fungi were counted. In two volunteers, no fecal beta-lactamase activity was detected, but ceftriaxone was present during treatment at concentrations of 1.8-2.0 mg/g of feces. Concomitantly, fecal counts of anaerobes in these volunteers dropped from 10.5 to less than 8 log10 colony-forming units (cfu)/g of feces, and those of Candida species increased more than 100-fold. However, in the feces of the four other volunteers, beta-lactamase activity was high during ceftriaxone administration, but no ceftriaxone was detected. In these volunteers, ceftriaxone administration was not followed by any significant change in counts of anaerobes or Candida species. This appeared to be due to the intraintestinal hydrolysis of ceftriaxone by resident beta-lactamase-producing anaerobes. In gnotobiotic mice associated with a human fecal flora containing no beta-lactamase-producing anaerobes, it was possible to prevent the deleterious effects of ceftriaxone on intestinal microbial composition and on colonization resistance (against a strain of Candida albicans and one of ceftriaxone-resistant Enterobacter cloacae) by feeding the animals with an association of four beta-lactamase-producing anaerobic strains.

Zinc is a common element in the human environment and constitutes an important trace element intervening in many biological processes. Toxicity of zinc is low; zinc deficiency represents, however, a hazard for human health. Zinc is not mutagenic and has little, if any, clastogenic properties. Zinc can induce tumours but only following local application, and does not represent a carcinogenic risk to man. It is still uncertain whether zinc can cause malignant transformation but zinc is needed for cellular proliferation of existing tumours and tumour growth is retarded by zinc deficiency. Zinc is not teratogenic; it can, in fact, avert teratogenicity of other agents. Conversely, zinc deficiency may be harmful to the developing organism.