Direct Observation of Optical Field Phase Carving in the Vicinity of Plasmonic Metasurfaces.

Plasmonic surfaces are mainly used for their optical intensity concentration properties that allow for enhancement of physical interaction like in nonlinear optics, optical sensors, or tweezers. Phase response in plasmonic resonances can also play a major role, especially in a periodic assembly of plasmonic resonators like metasurfaces. Here we show that localized surface plasmons collectively excited by a guided mode in a metallic nanostructure periodic chain present nonmonotonous phase variation along the 1D metasurface, resulting from both selective Bloch mode coupling and dipolar coupling. As shown by near-field measurements, the phase profile of the highly concentrated optical field is carved out in the vicinity of the metallic metasurface, paving the way to unusual local optical functions.

Observation of near-field dipolar interactions involved in a metal nanoparticle chain waveguide.

We present near-field measurements of transverse plasmonic wave propagation in a chain of gold elliptical nanocylinders fed by a silicon refractive waveguide at optical telecommunication wavelengths. Eigenmode amplitude and phase imaging by apertureless scanning near-field optical microscopy allows us to measure the local out-of-plane electric field components and to reveal the exact nature of the excited localized surface plasmon resonances. Furthermore, the coupling mechanism between subsequent metal nanoparticles along the chain is experimentally analyzed by spatial Fourier transformation on the complex near-field cartography, giving a direct experimental proof of plasmonic Bloch mode propagation along array of localized surface plasmons. Our work demonstrates the possibility to characterize multielement plasmonic nanostructures coupled to a photonic waveguide with a spatial resolution of less than 30 nm. This experimental work constitutes a prerequisite for the development of integrated nanophotonic devices.

A kinetic model for the degradation of benzothiazole by Fe3+-photo-assisted Fenton process in a completely mixed batch reactor.

The degradation of benzothiazole in aqueous solution by a photo-assisted Fenton reaction has been studied in a batch reactor in the pH range 2.0 - 3.2 and for H2O2 and Fe(III) concentrations respectively between 1.0 x 10(-3) - 1.5 x 10(-1) and 1.0 x 10(-6) - 4.0 x 10(-6) M. A kinetic model has been developed to predict the decay of benzothiazole at varying reaction conditions. The use of kinetic constants from the literature in the model allows to simulate the system behavior by taking into account the influence of pH, hydrogen peroxide, Fe(III) and sulfate concentrations and the ionic strength.

A 'de novo' arisen case of angioedema C1-inhibitor deficiency dependent: possible mutagenic effect of azathioprine?

It is reported that a C1-inhibitor (CI-INH) deficiency dependent angiodema case arose 'de novo' in a child without a family history of this disease. His mother was undergoing immunosuppressive therapy (50 mg of azathioprine plus 8 mg of methyl-prednisolone daily) during pregnancy, uninterrupted for seven years because of a kidney transplant. All the other known causes of acquired C1-INH deficiency were excluded. An involvement of an azathioprine-induced C1-INH gene mutation is hypothised.

High prevalence of hepatitis C virus infection in patients with B-cell lymphoproliferative disorders in Italy.

Starting from the observation that a number of consecutive patients with non-Hodgkin's lymphoma (NHL) resulted positive for hepatitis C virus (HCV) antibodies on routine testing, we set up a survey for HCV contact prevalence in all patients with lymphoproliferative disorders (LPD) followed in our institution. We searched for HCV antibodies by a third-generation ELISA technique, followed by a confirmation test (RIBA III); serum viral RNA and HCV genotype were investigated by a RT-PCR technique. We screened a total of 315 patients suffering from B-NHL (91), multiple myeloma (56), MGUS (48), chronic lymphocytic leukemia (57), Waldentrom's macroglobulinemia (13), Hodgkin's disease (HD)(43), and T-NHL (9). While only 1 of 52 patients with a non-B-LPD (HD or T-NHL) had signs of HCV contact (i.e., 1.9%, which is in the range of the normal population in the South of Italy), 59 of 263 patients with a B-LPD (22.4%) had HCV antibodies or RNA, or both, with no major differences among the various types of disorders, except for WM, in which the rate was higher (61.5%). The same prevalence was found for patients tested at diagnosis or during the follow-up, and in transfused or never-transfused patients. Only a few patients were aware of having a liver disease; one-half of HCV-positive patients never had transaminase increase. A review of data from Central and Northern Italy is included, showing similar findings; a report from Japan has confirmed such an association, while limited surveys in England have not revealed any correlation. These findings may have important biological and clinical implications.

Twenty-four hour melatonin pattern in acromegaly: effect of acute octreotide administration.

We investigated the melatonin (MT) circadian rhythm before and after somatostatin (octreotide) acute administration in ten subjects (4 M, 6 F. 23-52 yr old) with active acromegaly due to pituitary microadenoma. Blood samples were drawn every 2 hours over a 48-h span; after 24-h basal blood collection, octreotide (Sandostatin, Sandoz) 100 micrograms sc/8 h was administered. As control, 7 healthy adult subjects (3M, 4F; 26-50 yr old) were studied in basal condition over a 24-h span. Plasma MT and GH levels were measured by RIA in each sample, IGF-1 levels were measured by immunoradiometric assay in basal and after octreotide morning samples. The comparisons were made by Mann-U-Withney and Wilcoxon test as appropriate; the existence of a MT circadian rhythm was validated by cosinor analysis; GH and MT values were correlated by Pearson's correlation coefficient. All of 7 control subjects and 2 of 10 acromegalics had significant 24-h MT rhythm. The area under curve (AUC), mesor and amplitude of the MT rhythms in acromegalics were significantly lower than in the controls (p < 0.001, 0.002 and 0.0006, respectively), with an earlier acrophase (median value: 22:14 vs 02:08 h of controls). Basal plasma IGF-1 levels and circadian GH concentrations were significantly increased in acromegalics in comparison with the control group. Octreotide administration significantly reduced GH, restoring a circadian MT rhythm in 5 of 10 acromegalics, with MT mean mesor and AUC not different from controls. Mean amplitude still remained lower than controls (p < 0.0006), with an earlier acrophase (median 00:01 h). No significant correlation was found between individual GH and MT levels. Our data indicate a reduction of MT circadian secretion in acromegaly, due especially to a blunted nocturnal increase with earlier MT peak; moreover, acute octreotide administration increase MT levels without modifying amplitude and phase of night-time secretion significantly. These findings suggest a negative interrelationship between GH and MT secretions or a facilitatory influence of somatostatin on daytime MT release only. This partial recovery of pineal secretion after octreotide in acromegalics could be a clinically significant contribution to improve their quality of life, considering that MT is involved in the regulation of several important functions.

Antisperm antibodies in prepubertal boys treated with chemotherapy for malignant or non-malignant diseases and in boys with genital tract abnormalities.

In several childhood diseases which have the ensuing risk of infertility in adult life because of direct hypothalamic-pituitary-testicular axis involvement, or as a consequence of therapeutic toxicity, the role of antisperm antibodies (ASA) is rarely addressed. The aim of this study was to investigate the occurrence of ASA in a large prepubertal male population (aged 1.2-13 years) consisting of three groups: Group I, 52 patients affected by malignant diseases (lymphoblastic leukaemia, malignant lymphoma, or Wilm's tumour, n = 42), or by nephrotic syndrome (n = 10); Group II, 212 patients with either genital tract abnormalities (cryptorchidism, inguinal hernia, funicular torsion or hypospadias, n = 202), or cystic fibrosis (n = 10); Group III: 100 age-matched normal boys. Group I and II patients were investigated at diagnosis and during or after treatment (drug, radiation or surgical therapy). Group III was used as controls. ASA were detected in sera by the Tray Agglutination Test (TAT) and indirect IgG, IgA and IgM immunobead tests (iIBT). All normal boys were ASA-negative using both tests. Twenty-six out of the 264 patients (9.8%) in Groups I and II were ASA-positive: 23 (8.7%) patients had a positive TAT with a titre of 1:32 to 1:128, whilst 14 (5.3%) had IgG-ASA after iIBT. Eleven patients (4.1%) were ASA-positive in both tests. Of the 26 ASA-positive boys, 24 had genital tract abnormalities (cryptorchidism, testicular torsion, hypospadias) and two had leukaemia with testicular infiltration. Treatment did not modify antibody positivity. Our data confirm that ASA can occur in prepubertal boys, mostly among cases with urogenital pathology, but that it is rare among other cases. Therefore autoimmune reaction against spermatozoa is another factor that should be considered in the evaluation of several conditions in childhood involving reproductive tract alteration and potential impairment of the blood testis (Sertoli cell) barrier.

Prevalence of antisperm antibodies by SpermMARtest in subjects undergoing a routine sperm analysis for infertility.

To evaluate the prevalence of antisperm antibodies (ASA) attached to the sperm plasma membrane in male partners of infertile couples, the binding of latex particles to spermatozoa was investigated using SpermMARtest, included routinely in semen analysis. A total of 860 men were examined, who were referred consecutively for semen analysis. Of these, 750 men were referred because of infertility (0.6-10 years in duration) whereas 110 were volunteers with a history of previous fertility. Samples were assessed by the SpermMARtest kit using latex particles sensitized with human IgG. Sperm-latex binding was read after 3 min and samples scored as negative, positive or highly positive when < 10, > 10-40, or > 40% binding occurred, respectively. Of the samples 132 (17.3%) were excluded because of azoo- or severe oligo-asthenozoospermia. IgG attached to spermatozoa were detected in nearly 13% of semen samples from the infertile population and in one of 110 fertile men (0.9%). From the infertile group, 6.2% of samples showed > 40% binding, and 6.7% intermediate binding, with an overall ASA prevalence of 12.9% in subjects undergoing semen analysis for infertility.