Topological insulator metamaterial with giant circular photogalvanic effect.

One of the most notable manifestations of electronic properties of topological insulators is the dependence of the photocurrent direction on the helicity of circularly polarized optical excitation. The helicity-dependent photocurrents, underpinned by spin-momentum locking of surface Dirac electrons, are weak and easily overshadowed by bulk contributions. Here, we show that the chiral response can be enhanced by nanostructuring. The tight confinement of electromagnetic fields in the resonant nanostructure enhances the photoexcitation of spin-polarized surface states of topological insulator Bi1.5Sb0.5Te1.8Se1.2, leading to an 11-fold increase of the circular photogalvanic effect and a previously unobserved photocurrent dichroism (ρcirc = 0.87) at room temperature. The control of spin transport in topological materials by structural design is a previously unrecognized ability of metamaterials that bridges the gap between nanophotonics and spin electronics, providing opportunities for developing polarization-sensitive photodetectors.

Gender differences and occupational factors for the risk of obesity in the Italian working population.

BACKGROUND: Obesity is a multifactorial condition and a major risk factor associated with several non-communicable diseases, such as cardiovascular disease, and with a higher risk of premature death and disability. Sex-specific factors have key roles and must be taken into consideration in studying occupational factors associated with the risk of obesity. The aim of this study was to investigate gender differences in body mass index (BMI) in a large cohort representative of Italian workers and, correlating this index with several demographic and occupational variables, to verify sex- and work-dependent differences in the risk of obesity. METHODS: We utilized data from INSuLa, a cross-sectional, nationally representative survey of the Italian worker population conducted in 2013 by the Italian Workers' Compensation Authority to investigate health and safety at work. Analyses were run on a sample of 8000 Italian workers, aged from 16 to 64 years. Logistic regression models were employed to assess gender differences in the relation between occupational characteristics and BMI. We adjusted for age, education, variables related to health protection at work, and chronic conditions and diseases. RESULTS: There were several significant differences in the BMI between males and females, linked to some occupational factors. For instance, female shift workers were 1.32 times (95% CI 1.11-1.57) more likely to be overweight or obese than normal-weight workers, and this association was maintained when controlling for confounders. The likelihood of overweight or obesity among women who worked 1-2 night shifts per week was significantly higher - 1.5-1.6 times - than those on day shifts. CONCLUSIONS: Gender-specific differences in occupational factors associated with the risk of obesity are useful with a view to characterizing this risk and helping identify workplace-targeted intervention strategies.

Infrared dielectric metamaterials from high refractive index chalcogenides.

High-index dielectric materials are in great demand for nanophotonic devices and applications, from ultrathin optical elements to metal-free sub-diffraction light confinement and waveguiding. Here we show that chalcogenide topological insulators are particularly apt candidates for dielectric nanophotonics architectures in the infrared spectral range, by reporting metamaterial resonances in chalcogenide crystals sustained well inside the mid-infrared, choosing Bi2Te3 as case study within this family of materials. Strong resonant modulation of the incident electromagnetic field is achieved thanks to the exceptionally high refractive index ranging between 7 and 8 throughout the 2-10 µm region. Analysis of the complex mode structure in the metamaterial allude to the excitation of circular surface currents which could open pathways for enhanced light-matter interaction and low-loss plasmonic configurations by coupling to the spin-polarized topological surface carriers, thereby providing new opportunities to combine dielectric, plasmonic and magnetic metamaterials in a single platform.

Current Espghan Guidelines for Celiac Disease in Pediatric Age, Tertiary Care Center Experience: A Proposal for Further Simplification.

According to the 2012 ESPGHAN criteria for diagnosis of celiac disease (CD), duodenal biopsy (DB) can be avoided in children with a clear malabsorption syndrome, anti-tissue transglutaminase IgA (tTG2) ≥ 10x the cut-off, anti-endomysium IgA (EMA) and HLA DQ2/DQ8 genes. The aim of this study is to report our experience and evaluate the accuracy of the actual guidelines. PATIENTS AND METHODS: This is a retrospective study conducted on all patients diagnosed CD from 2012 to 2018 in our Center. For all patients enrolled were analyzed: data of family history, symptoms, serology, genetics, Marsh grade and follow-up. RESULTS: A total of 481 children [mean age 6,4 yrs; F:M= 1.8:1] were included in the study. The mean age of patients who were not subject to DB was lower (4.51 yrs) comparing with patients that received DB (6.48 yrs). Out of the 256 patients with anti-tTG2 ≥ 10 fold, 121 underwent DB because of mild symptoms (84/121) or no symptoms (37/121). In all cases Marsh type 3 was found and HLA haplotypes was compatible with CD diagnosis. CONCLUSIONS: Our study confirms that the serology has a primary importance to diagnose CD, regardless of the symptoms. These data suggest that biopsy and HLA haplotypes search, in presence of anti-tTG2 IgA ≥ 10x the cut-off, are wasteful and unhelpful for the patients.

The end of measles and congenital rubella: an achievable dream?

BACKGROUND: Despite substantial progress towards measles and rubella control, outbreaks continue to threaten elimination goals worldwide. STUDY DESIGN: This paper aims to document progress towards the global eradication of measles and rubella. In particular, it investigates the major challenges faced by Italy in reaching the elimination goals. METHODS: A review of the most important literature was carried out. Furthermore, a systematic review of the scientific literature on measles and rubella in the Italian setting was performed for the period 2000-2016. RESULTS: In the National Plan 2010-2015, Italy renewed its commitment to eliminate measles and rubella by 2015. However, Italy recently experienced a high measles burden (2,205 cases in 2013, 1,694 in 2014). Between June 2015 and May 2016, 515 cases were reported, accounting for 28% all cases in Europe. Immunization coverage decreased in recent years, with no Region reaching the 95% target. The systematic review included a total of 175 papers, with an upward trend in the number of published articles, which demonstrates an increasing interest in the field of measles and rubella. The review highlights the need to improve the commitment of the Italian Regions to the elimination goals; to promote Supplementary Immunization Activities (SIAs); to improve the communication skills of health care workers; to improve the health literacy of citizens; and to enhance integrated measles and rubella surveillance. CONCLUSION: Elimination of measles and rubella in Italy will require a substantial improvement in both commitment of the 21 Regions and activity of the whole country towards the WHO goals.

Electric field controlled columnar and planar patterning of cholesteric colloids.

We study how dispersions of colloidal particles in a cholesteric liquid crystal behave under a time-dependent electric field. By controlling the amplitude and shape of the applied field wave, we show that the system can be reproducibly driven out of equilibrium through different kinetic pathways and navigated through a glassylike free energy landscape encompassing many competing metastable equilibria. Such states range from simple Saturn rings to complex structures featuring amorphous defect networks, or stacks of disclination loops. A nonequilibrium electric field can also trigger the alignment of particles into columnar arrays, through defect-mediated force impulses, or their repositioning within a plane. Our results are promising in terms of providing new avenues towards controlled patterning and self-assembly of soft colloid-liquid crystal composite materials.

A study on occupational exposure of Sicilian farmers to Giardia and Cryptosporidium.

INTRODUCTION: A cross-sectional study was undertaken to determine the prevalence of Giardia and Cryptosporidium in calves of Palermo area (Sicily) and to evaluate the occupational risk associated with occurrence of zoonotic genotypes. METHODS: A total of 217 faecal samples, from 149 calves (between 2 and 240 days of age) and 68 farmers, were collected in 19 cattle-farms of Palermo area. A questionnaire regarding demographic characteristics and personal hygienic measures was submitted to all farmers. All faecal samples were analyzed by Immunofluorescence assay and Polimerase Chain Reaction (PCR); genotypes were determined by DNA sequencing of Triose Phosphate Isomerase gene for Giardia and Small Subunit Ribosomal RNA gene for Cryptosporidium. RESULTS: None farmer tested was positive for Giardia and Cryptosporidium, whereas these protozoa were respectively detected in 53 (including 5 with zoonotic G. duodenalis genotype A) and 17 (of which 1 with zoonotic C. ubiquitum) of the examined calves. DISCUSSION: The results indicate that the risk of transmitting both protozoa to farmers in Palermo area is negligible although it cannot be considered null because of identification of human genotypes/species in calves.

Electron-beam-driven collective-mode metamaterial light source.

We demonstrate experimentally that the energy from a highly localized free-electron-beam excitation can be converted via a planar plasmonic metamaterial to a low-divergence free-space light beam. This emission, which emanates from a collectively oscillating coupled metamolecule nanoantenna ensemble much larger in size than the initial excitation, is distinctly different from cathodoluminescence and bears some similarity with laser light. It offers a novel, flexible paradigm for the development of scalable, threshold-free light sources.

Transmitting hertzian optical nanoantenna with free-electron feed.

A pair of coupled gold nanorods excited by a beam of free electrons acts as a transmitting Hertzian antenna in the optical part of the spectrum. Significantly enhanced resonant emission is observed from the antenna when the electron beam is injected around the junction between the rods, where the local density of electromagnetic states is elevated.

Cathodo- and photoluminescence in Yb(3+)-Er(3+) co-doped PbF(2) nanoparticles.

We have prepared and studied the PbF(2):(Yb(3+),Er(3+)) co-doped nanoparticles, with chemical formula (Yb-Er)(x)Pb(1-x)F(2+x), where x = 0.29, Yb(3+)/Er(3+) = 6, and estimated the energy efficiency for their cathodoluminescence, mostly of Yb(3+), and up-conversion photoluminescence of Er(3+) to reach more than 0.5% and 20%, respectively, which may be the highest to date for rare-earth doped nanoparticles. Electron beam induced temperature rise in the nanoparticles has been estimated by measuring the ratio of green emission bands of Er(3+). These high efficiencies are due to high doping level of nanoparticles and due to low phonon energy of the PbF(2) host.

Circulating free nitrotyrosine and cognitive decline.

OBJECTIVE: To determine if the circulating nitrotyrosine level significantly correlates with parameters measuring cognitive abilities. MATERIALS AND METHODS: One-hundred and twelve community-living subjects (ranging in age from 27 to 98 years) were evaluated for cognitive abilities [Mini Mental State Examination (MMSE) score] and circulating free nitrotyrosine plasma level, as well as for several variables that might influence cognitive abilities (age, education) and nitrotyrosine level (body mass index, haematological parameters, cardiovascular and inflammatory indices). RESULTS: In the sub-group of cognitively impaired subjects (score at MMSE < 23.9), but not in that of cognitively not impaired subjects, a significant inverse correlation exists between nitrotyrosine level and MMSE score (r = -0.378; P < 0.02). CONCLUSIONS: The finding, if confirmed by longitudinal studies, could play a role in the management of the subjects with Mild Cognitive Impairment, the clinical condition considered as a transitional state between the changes of cognitive ability in normal aging and dementia.

Light well: a tunable free-electron light source on a chip.

The passage of a free-electron beam through a nanohole in a periodically layered metal-dielectric structure creates a new type of tunable, nanoscale radiation source--a "light well". In the reported demonstration, tunable light is generated at an intensity of approximately 200 W/cm(2) as electrons with energies in the 20-40 keV range are injected into gold-silica well structures with a lateral size of just a few hundred nanometers.

Mycophenolate mofetil in primary glomerulopathies.

Mycophenolate mofetil is an immunosuppressive agent that blocks purine biosynthesis, inhibits T and B-lymphocyte and mesangial proliferation. Mycophenolate mofetil is not nephrotoxic like calcineurin inhibitors and is widely used in solid-organ transplantation. Recently, mycophenolate mofetil has been introduced in the treatment of autoimmune diseases and primary glomerulopathies. This review analyzes the literature currently available on the treatment of primary glomerulopathies with mycophenolate mofetil. Encouraging results have been obtained in minimal change nephropathy where it may help to reduce the use of steroids in these patients who are often very young. The results obtained in medium and high risk patients with focal segmental glomerulonephritis and idiopathic membranous nephropathy were less encouraging. Conflicting results have been reported on IgA nephropathy in controlled trials. None of these studies attained level A evidence, meaning that randomized control trials of sufficient statistical significance are necessary to estimate the real effectiveness of mycophenolate mofetil in primary glomerulopathies.

Influence of methylprednisolone on plasma homocysteine levels in cadaveric renal transplant recipients.

The aim of the present study was to investigate plasma homocysteine levels in renal transplant recipients in the course of steroid-based or steroid-free immunosuppression. Data from 32 patients were retrospectively analyzed according to the steroid immunosuppressive regimen. The 20 recipients on methylprednisolone (MP) plus cyclosporine (CyA) or tacrolimus (TRL) (n = 20) showed similar creatinine levels when compared with those on calcineurin inhibitors plus mycophenolate mofetil (MMF; n = 12), (1.6 +/- 1.5 vs 1.6 +/- 0.4 mg/dL; P = NS) but significantly higher total plasma homocysteine (tHcy) levels (28.5 +/- 12.5 vs 16.3 +/- 5.5 micromol/L; P < .05). No differences of tHcy levels have been observed when patients were analyzed according to CyA- or TRL-based immunosuppression regardless of MP or MMF associations. Our data suggest that recipients, particularly those on steroid-based immunosuppression, should receive homocysteine-lowering treatment early after transplantation.

[Collaborative study on peritoneal dialysis (PD) as first dialysis treatment in an Italian region: 1994-2000]. / Studio collaborativo sulla dialisi peritoneale (DP) come primo trattamento nel Lazio: 1994-2000.

BACKGROUND: In Lazio, only about 5% of uremic patients are on peritoneal dialysis (PD). The present study focuses on the parameters of PD selection, the treatment schedules, and the clinical outcomes of PD patients in the nine public facilities offering a PD program. A cohort of 249 first-time PD patients, from July 1, 1994 to December 31, 2000, was retrospectively considered. METHODS: For the enrollment of the patients, the Regional Dialysis Registry databank was consulted. On December 31, 2000, a systematic review of patient charts was performed to extract the reasons for the PD choice, details of PD schedule, peritonitis episodes, reasons for drop-out, and patient survival rates. In regard to technique success-defined as the probability of having a patient alive on PD-change of modality and death were considered as final events. In regard to patient survival, only death, even in the first 2 months after a shift to hemodialysis, was considered the end point. RESULT: The main PD selection reasons were patient and/or nephrologist preference in 90% of cases. One-hundred eighty-nine patients (76%) had been started on CAPD. During the follow-up, 38.2% dialysis schedules had been modified at least once. At the end of follow-up, 41.2% patients were on APD. The peritonitis rate was one episode per 30 patient-months (1 per 27 patient-months in CAPD; 1 per 37 patient-months in APD; p = 0.08). The technique success rate was 66.3% after 2 years and 49.8% after 3 years. The patient survival rate was 81.1% after 2 years and 68.7% after 3 years. CONCLUSIONS: Patients chose PD as a first dialysis treatment mainly because of reasons unrelated to their clinical status. The technique's success, patient mortality rates, and the peritonitis rate do not explain the low PD diffusion in the region. The peritonitis rate meets the target criteria for excellence recommended by the Italian Society of Nephrology. The observed outcomes may have been favored by the selection of motivated patients and by the increased use of APD.

Homology modeling and identification of serine 160 as nucleophile of the active site in a thermostable carboxylesterase from the archaeon Archaeoglobus fulgidus.

The hyperthermophilic Archaeon Archaeoglobus fulgidus has a gene (AF1763) which encodes a thermostable carboxylesterase belonging to the hormone-sensitive lipase (HSL)-like group of the esterase/lipase family. Based on secondary structure predictions and a secondary structure-driven multiple sequence alignment with remote homologous proteins of known three-dimensional structure, we previously hypothesized for this enzyme the alpha/beta-hydrolase fold typical of several lipases and esterases and identified Ser160, Asp 255 and His285 as the putative members of the catalytic triad. In this paper we report the building of a 3D model for this enzyme based on the structure of the homologous brefeldin A esterase from Bacillus subtilis whose structure has been recently elucidated. The model reveals the topological organization of the fold corroborating our predictions. As regarding the active-site residues, Ser160, Asp255 and His285 are located close each other at hydrogen bond distances. The catalytic role of Ser160 as the nucleophilic member of the triad is demonstrated by the [(3)H]diisopropylphosphofluoridate (DFP) active-site labeling and sequencing of a radioactive peptide containing the signature sequence GDSAGG.

Omeprazole-induced acute interstitial nephritis.

Omeprazole is a proton pump inhibitor widely used for the treatment of peptic ulcer disease. We report a patient presenting nonoliguric acute renal failure following omeprazole treatment. Both eosinophilia and eosinophiluria were observed, and the patient was diagnosed as having drug-induced acute interstitial nephritis. Renal failure spontaneously resolved when omeprazole was discontinued.

Hypergastrinemia in rats with azoxymethane-induced colon cancers.

Gastrin has been suggested to be involved in the promotion and progression of colon cancer. Mice colon cancers and colon-carcinoma cell lines are stimulated to grow by gastrin, and gastrin receptors have been found in the majority of human colon-tumor specimens. High serum gastrin levels have been reported in patients with colon polyps and cancers, together with increased ornithine decarboxylase (ODC) activity. Since gastrin stimulates ornithine decarboxylase in colon cancer cells in vitro it has been suggested that increased synthesis of intracellular polyamines is one of the mechanisms activated by the hormone. In order to confirm the presence of hypergastrinemia in colon cancer and to investigate the relationship between plasma gastrin and tumor growth, we used an animal model of colon carcinogenesis that minimizes the possible bias of human studies, related to varying diet, age and environmental factors. We evaluated blood gastrin levels in 35 rats with colon cancer induced by the carcinogen azoxymethane (AOM), and we correlated gastrinemia with tumor proliferation, assessed by thymidine-labeling index (TLI) and ODC activity; 6 animals constituted the control group. Gastrin levels in rats with AOM-induced tumors were significantly higher than in controls. Significantly higher TLI and ODC activity were found in the tumors of hypergastrinemic rats than in neoplasms of animals with normal gastrin levels. Our data provide additional evidence of a role for gastrin as trophic hormone for colon neoplastic cells.

Cell kinetics and polyamine enzymes in the intestinal mucosa of rats with azoxymethane induced tumours.

We studied the proliferative activity and the modifications in ornithine decarboxylase (ODC) and diamine oxidase (DAO), enzymes involved in polyamine metabolism, in the apparently normal intestinal mucosae of rats with azoxymethane induced tumours. Fifty rats were treated with six weekly injections of 15 mg/kg body weight azoxymethane (AOM). Six rats died during the treatment. All the surviving rats developed intestinal tumours; tumour incidence was 93.1% (41/44) in the left colon, 40.9% (18/44) in the right colon and 45.4% (20/44) in the small bowel. In the normal-appearing mucosa close to intestinal tumours we found an extension of the normal proliferative compartment to the upper third of the crypts (stage I abnormality) and a shift of most of the DNA synthesizing cells from the basal region to the middle and upper third (stage II abnormality). Furthermore, the intestinal mucosa characterized by proliferative abnormalities showed an ODC activity significantly higher than the normal mucosa of control rats (small bowel: 1.01 +/- 0.26 vs 0.42 +/- 0.15, P < 0.01; right colon: 1.32 +/- 0.34 vs 0.25 +/- 0.02, P < 0.001; left colon: 1.93 +/- 0.35 vs 0.22 +/- 0.01, P < 0.01). We also detected a significant decrease of DAO activity in the mucosa of the small bowel and right colon of treated rats compared to controls (0.86 +/- 0.09 vs 4.39 +/- 0.85, P < 0.01; 1.04 +/- 0.43 vs 3.80 +/- 0.91, P < 0.01, respectively), while DAO activity in the left colon was unchanged. The lower incidence of tumours in the small bowel and right colon suggests the presence of factors protecting these segments from carcinogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)