Optical design of InGaN/GaN nanoLED arrays on a chip: toward: highly resolved illumination.

The physical laws of diffraction limit the spatial resolution of optical systems. In contrary to most superresolution microscopy approaches used today, in our novel idea we are aiming to overcome this limit by developing a spatially resolved illumination source based on semiconductor nanoscale light emitting diode (nanoLED) arrays with individual pixel control. We present and discuss the results of optical simulations performed for such nanoLED emitter arrays and analyze the theoretical limits of this approach. As possible designs we study arrays of GaN nanofins and nanorods (obtained by etching nanofin arrays), with InGaN/GaN multi quantum wells embedded as active regions. We find that a suitable choice of the array dimensions leads to a reasonably directed light output and concentration of the optical power in the near field around an activated pixel. As a consequence, the spatial resolution for this type of microscopy should only be limited by the pixel pitch, and no longer by the optical diffraction. Realization of optimized nanoLED arrays has a potential to open new field of chip based superresolution microscopy, making super-high spatial resolution ubiquitously available.

Author Correction: Titanium-carbide MXenes for work function and interface engineering in perovskite solar cells.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Titanium-carbide MXenes for work function and interface engineering in perovskite solar cells.

To improve the efficiency of perovskite solar cells, careful device design and tailored interface engineering are needed to enhance optoelectronic properties and the charge extraction process at the selective electrodes. Here, we use two-dimensional transition metal carbides (MXene Ti3C2Tx) with various termination groups (Tx) to tune the work function (WF) of the perovskite absorber and the TiO2 electron transport layer (ETL), and to engineer the perovskite/ETL interface. Ultraviolet photoemission spectroscopy measurements and density functional theory calculations show that the addition of Ti3C2Tx to halide perovskite and TiO2 layers permits the tuning of the materials' WFs without affecting other electronic properties. Moreover, the dipole induced by the Ti3C2Tx at the perovskite/ETL interface can be used to change the band alignment between these layers. The combined action of WF tuning and interface engineering can lead to substantial performance improvements in MXene-modified perovskite solar cells, as shown by the 26% increase of power conversion efficiency and hysteresis reduction with respect to reference cells without MXene.

Graphene-Induced Improvements of Perovskite Solar Cell Stability: Effects on Hot-Carriers.

Hot-carriers, that is, charge carriers with an effective temperature higher than that of the lattice, may contribute to the high power conversion efficiency (PCE) shown by perovskite-based solar cells (PSCs), which are now competitive with silicon solar cells. Hot-carriers lose their excess energy in very short times, typically in a few picoseconds after excitation. For this reason, the carrier dynamics occurring on this time scale are extremely important in determining the participation of hot-carriers in the photovoltaic process. However, the stability of PSCs over time still remains an issue that calls for a solution. In this work, we demonstrate that the insertion of graphene flakes into the mesoscopic TiO2 scaffold leads to stable values of carrier temperature. In PSCs aged over 1 week, we indeed observe that in the graphene-free perovskite cells the carrier temperature decreases by about 500 K from 1800 to 1300 K, while the graphene-containing cell shows a reduction of less than 200 K after the same aging time delay. The stability of the carrier temperature reflects the stability of the perovskite nanocrystals embedded in the mesoporous graphene-TiO2 layer. Our results, based on femtosecond transient absorption measurements, show that the insertion of graphene can be beneficial for the design of stable PSCs with the aim of exploiting the hot-carrier contribution to the PCE of the PSCs.

A multifinger microtriode with carbon nanotubes field emission cathode operating at GHz frequency.

Vacuum microelectronic devices play an important role in the field of micro- and nano-electronics and they have been strongly developed in recent decades. Vacuum microelectronics are mainly based on the field emission effect and the employment of electrons in vacuum in a device with dimensions from tenths to hundredths of a micrometer. In this work, we present the development of a carbon-nanotube-based multifinger microtriode operating from 0.5 to 2 GHz. In this frequency range, a minimum RF signal gain of 5 dB is achieved. Such a device represents an optimized alternative to the standard Spindt-type microtriode. The advantage of such multifinger architecture consists in the possibility to reduce the cathode-grid capacitance by reducing the overlap between the two electrodes using a parallel patterning. This approach allows increasing the cut-off frequency of the devices with respect to the Spindt-type triode. We realized a prototype of the multifinger triode and the field emission properties have been characterized. The frequency behavior has been measured, demonstrating the possibility to amplify RF signal.

Stroke units in Italy: engaging the public in optimizing existing resources.

BACKGROUND AND PURPOSE: The lack of a wide implementation of stroke units (SU)s in Italy appears to accompany the underuse of the operating units. Community awareness of acute stroke care options may affect stroke resource use. Our aim was to determine the level of knowledge about SUs and tissue-plasminogen activator (t-PA) treatment amongst Italian adults and investigate its relationship to local stroke services implementation. METHODS: A nation-based telephone survey was carried out in a sample of 1000 residents aged >18 years in May-June 2010. The questionnaire included close-ended questions regarding knowledge of SUs and t-PA treatment. Number and location of both SUs and t-PA treatments were provided by a concurrent national hospital-based survey. The prevalence and distribution of acute stroke care awareness in the community was examined and multivariate analyses were generated. RESULTS: Amongst the 1000 participants (474 men, mean age 48.8 ± 17.2), only 26.2% reported knowing about the availability of t-PA treatment and only 15% were aware of the existence of SUs. Awareness of both SUs and t-PA was significantly associated only with education. These associations remained significant in the multivariate analyses. The degree of stroke services implementation (in terms of SUs/inhabitant rates and number of t-PA treatments) was not associated with SU and t-PA awareness. CONCLUSIONS: This is the first European study that explored public knowledge about t-PA treatment and SUs. Italian adults proved insufficiently educated about SUs and t-PA; there is no higher awareness in areas with a greater supply of stroke services. This might partially explain the underuse of Italian SUs.

Effectiveness of public stroke educational interventions: a review.

BACKGROUND AND PURPOSE: Recognizing stroke symptoms and acting quickly can reduce death and disability, but public awareness of stroke risk factors, symptoms and what to do about them is still limited. Stroke educational campaigns are used worldwide but there are few published evaluations of such campaigns. METHODS: The literature from 1999 to 2012 on the effectiveness of stroke educational campaigns was reviewed and summarized with narrative synthesis. Web-based campaigns were also described. Three databases and one search engine were explored with two keywords (stroke campaign and stroke promotion). The reference lists of all included articles were also examined. RESULTS: Twenty-two intervention studies and five web-based campaigns were included in the review. Most interventions proved partially effective, in terms of gender preference (women) or type of information retained or media preferred. Only one intervention proved ineffective. Mass media campaigns can be effective but require sustained funding, and their ability to target high-risk subgroups, whether aging, linguistic or socioeconomic, is unclear. Three community-based participatory stroke promotion interventions proved partially effective, but the small sample sizes might have underpowered the results. Web-based campaigns are efficient in reaching a large number of people but tend to attract a selected and self-selected population. CONCLUSIONS: Stroke educational campaigns have the potential to improve knowledge and awareness and change the behavior of a large number of people. Health promoters and investigators must adopt flexibility and participatory mentality to develop cost-effective interventions. Both community-based campaigns and E-tools should be integrated within a comprehensive multifaceted stroke promotion strategy to expand their reach.

Solid-state solar modules based on mesoscopic organometal halide perovskite: a route towards the up-scaling process.

We fabricated the first solid state modules based on organometal halide perovskite CH3NH3PbI3-xClx using Spiro-OMeTAD and poly(3-hexylthiophene) as hole transport materials. Device up-scaling was performed using innovative procedures to realize large-area cells and the integrated series-interconnections. The perovskite-based modules show a maximum conversion efficiency of 5.1% using both poly(3-hexylthiophene) and Spiro-OMeTAD. A long-term stability test was performed (in air, under AM1.5G, 1 Sun illumination conditions) using both materials showing different behaviour under continuous light stress. Whilst the poly(3-hexylthiophene)-based module efficiency drops by about 80% with respect to the initial value after 170 hours, the Spiro-based module shows a promising long-term stability maintaining more than 60% of its initial efficiency after 335 hours.

Pemphigus vulgaris in a patient with arthritis and uveitis: successful treatment with immunosuppressive therapy and acyclovir.

A case of pemphigus vulgaris in a 41-year-old man with undifferentiated arthritis and uveitis is described. Histology of labial mucosa showed acantholytic, necrotic, and multinucleated giant keratinocytes having some nuclear inclusions suggestive of a virus infection. Specific serological tests revealed IgG positivity for HSV-1, CMV, and EBV, while real-time polymerase chain reaction assay from a biopsy of the mucosal lesion showed the presence of HSV-1/2 DNA. Treatment with prednisone, methotrexate, and acyclovir induced the complete remission of mucosal and joint symptoms, which then relapsed after interruption of antiviral therapy or immunosuppressive therapy. Therefore, a combined treatment with low doses of prednisone, methotrexate, and acyclovir was restarted and during 18 months of follow-up no recurrence was registered. Correlations between pemphigus and the herpes virus infection and also between autoimmune arthritis and herpetic agents have been well documented, but the exact role of the herpes virus in these disorders still needs further discussion. Our case strongly suggests that when autoimmune disorders do not respond to immunosuppressive agents, a viral infection should be suspected, researched, and treated.

Immunologic biomarkers for clinical and therapeutic management of psoriasis.

BACKGROUND: The therapeutic management of psoriasis includes conventional treatments as well as the new generation of highly effective TNF-α inhibitors. However, psoriasis has proven to be a complex therapeutic challenge and treatment failures are not uncommon. Thus, laboratory biomarkers of disease progression/therapeutic efficacy may greatly help in the clinical management of psoriasis. AIMS: To identify laboratory biomarkers for clinical management and therapeutic monitoring of psoriasis. METHODS: An observational study performed on 59 patients, presenting moderate to severe psoriasis, undergoing treatment with anti-TNF-α agents (etanercept, adalimumab, and infliximab). Soluble and cellular immune/inflammatory parameters were assessed at baseline and after 12 and 24 weeks of treatment. RESULTS: Clinical efficacy was achieved in 88% of the subjects at 12 weeks, reaching 90% after 24 weeks. IL-6 and IL-22, which were elevated at baseline, were significantly reduced, in association with a significant decrease of CLA+ T cells and an increase of Treg lymphocytes. T, B, and NK cell subsets and T cell response to recall antigens did not show any evidence of immune suppression. CONCLUSIONS: Immune/inflammatory parameters including IL-6 and IL-22, CLA+ T cells, and Treg lymphocytes may prove to be valuable laboratory tools for the clinical and therapeutic monitoring of psoriasis.

Continuous increase in HIV-1 incidence after the year 2000 among men who have sex with men in Rome: insights from a 25-year retrospective cohort study.

To assess trends in HIV-1 incidence and risk factors for seroconversion among men who have sex with men (MSM) resident in Rome, Italy, a retrospective longitudinal cohort study was conducted over 25 years. Incidence rates and trends were modelled using Poisson regression and risk factors were assessed by multivariate Cox models. Of 1,862 HIV-1-negative individuals, 347 seroconverted during follow-up. HIV-1 incidence rates increased from 5.2/100 persons/year (p/y) in 1986 (95% confidence interval (CI): 2.3­11.5) to 9.2/00 p/y in 1992 (95% CI: 6.4­13.0), decreased to 1.3/100 p/y in 2001 and increased until 2009 (11.7/100 p/y; 95% CI: 7.4­18.6). The risk of HIV-1 seroconversion increased during the study period in younger MSM (incidence rate ratio (IRR) = 17.18; 95% CI: 9.74­30.32 in 16­32 year-olds and IRR = 5.09; 95% CI: 2.92­8.87 in 33­41 year-olds) and in those who acquired syphilis (IRR = 7.71; 95% CI: 5.00­11.88). In contrast, the risk of seroconversion decreased among highly educated MSM (IRR = 0.54; 95% CI: 0.35­0.82) and those without Italian citizenship (IRR = 0.45; 95% CI: 0.28­0.71). The HIV epidemic in MSM living in Rome continues to expand. Targeted prevention programmes against sexually transmitted infections to enhance knowledge transfer and behavioural skills are urgently required.

Lichen sclerosus and the risk of malignant progression: a case series of 159 patients.

AIM AND METHODS: We analyzed 159 stored specimens of Lichen Sclerosus (LS) collected in the period 1999-2011 from 159 patients, in order to evaluate the histological patterns, clinical outcomes and possible associations with malignancies. The histopathologic analysis revealed 145 cases (males and females) with LS alone, 7 in whom penile LS was associated with spinocellular carcinoma (SCC), and 7 in whom LS was associated with a pseudocarcinomatous-hyperplasia (PCH). Extragenital LS was found in 20% (17/85) of the males and 78% (58/74) of the females. In the cases of SCC, immunohistochemical analyses was performed. RESULTS AND CONCLUSION: The results showed very low positivity to p16INK4A and Ki-67; biomolecular PCR was positive in only two cases, and in both cases the non-oncogenic genotype HPV 100 was detected. No important additional risk factors for malignancies were found (e.g., hormones, infections, other autoimmune diseases).

High mobility group box 1 is a novel substrate of dipeptidyl peptidase-IV.

AIMS/HYPOTHESIS: High mobility group box 1 (HMGB1) is a cytokine with a key role in tissue regeneration and angiogenesis. Previous studies have shown that topical application of HMGB1 to skin wounds of mouse models of diabetes enhanced vessel density and accelerated wound healing, suggesting that diabetes may affect endogenous HMGB1 functions. Dipeptidyl peptidase IV (DPP-IV/CD26) is a protease whose activity is increased in diabetes and whose inhibition improves glucose tolerance. Since HMGB1 contains potential DPP-IV cleavage sites, we determined whether HMGB1 may be a substrate for DPP-IV and whether DPP-IV-mediated cleavage may alter the biological activity of HMGB1. METHODS: Reversed phase HPLC, mass spectrometry and western blot analyses were performed to analyse and identify HMGB1 peptides generated following DPP-IV digestion. HMGB1 angiogenic functions in the presence of DPP-IV were evaluated in vitro and in vivo. HMGB1 protein was detected in the serum of type 2 diabetic patients before and after treatment with DPP-IV inhibitors. RESULTS: DPP-IV cleaved HMGB1 at its N-terminal region and affected its angiogenic functions. Specifically, DPP-IV inhibited HMGB1-induced endothelial cell migration and capillary-like structure formation, as well as HMGB1-mediated vascular network formation in Matrigel implants in mice. We had previously found that HMGB1 promoted endothelial cell migration through activation of extracellular regulated kinase signalling pathway. Here we showed that such an effect was abolished in the presence of DPP-IV. Finally, the N-terminal truncated form of HMGB1 was detected in the serum of type 2 diabetic patients, in whom DPP-IV inhibitors enhanced the levels of full-length HMGB1. CONCLUSIONS/INTERPRETATION: DPP-IV cleaves HMGB1 and, via this mechanism, inhibits HMGB1 angiogenic activity. Treatment with DPP-IV inhibitors may enhance HMGB1 activity in diabetic patients, thereby improving angiogenesis in this condition.

Changes in severity of depressive symptoms and mortality: the Italian Longitudinal Study on Aging.

BACKGROUND: Depression is recognized as being associated with increased mortality. However, there has been little previous research on the impact of longitudinal changes in late-life depressive symptoms on mortality, and of their remission in particular. METHOD: As part of a prospective, population-based study on a random sample of 5632 subjects aged 65-84 years, with a 10-year follow-up of vital status, depressive symptoms were assessed by the 30-item Italian version of the Geriatric Depression Scale (GDS). The number of participants in the GDS measurements was 3214 at baseline and 2070 at the second survey, 3 years later. Longitudinal changes in depressive symptoms (stable, remitted, worsened) were examined in participants in both evaluations (n=1941). Mortality hazard ratios (MHRs) according to severity of symptoms and their changes over time were obtained by means of Cox proportional hazards regression models, adjusting for age and other potentially confounding factors. RESULTS: Severity is significantly associated with excess mortality in both genders. Compared to the stability of depressive symptoms, a worsened condition shows a higher 7-year mortality risk [MHR 1.46, 95% confidence interval (CI) 1.15-1.84], whereas remission reduces by about 40% the risk of mortality in both genders (women MHR 0.55, 95% CI 0.32-0.95; men MHR 0.59, 95% CI 0.37-0.93). Neither sociodemographic nor medical confounders significantly modified these associations. CONCLUSIONS: Consistent with previous reports, the severity and persistence of depression are associated with higher mortality risks. Our findings extend the magnitude of the association demonstrating that remission of symptoms is related to a significant reduction in mortality, highlighting the need to enhance case-finding and successful treatment of late-life depression.

Effective treatment of Kaposi's sarcoma by electrochemotherapy and intravenous bleomycin administration.

The present prospective study was aimed at evaluating the long-term efficacy of local electrochemotherapy (ECT) with the intravenous administration of bleomycin, on disease progression and viral activity in classic Kaposi's sarcoma (cKS), a vascular tumor related to human herpes virus-8 infection. Eighteen patients affected by isolate or multiple cutaneous lesions, refractory to conventional treatments, although in the absence of visceral involvement, were enrolled in a study. Follow-up visits were performed after 4 weeks and every 6 months for up to 48 months. A more extensive exploration of the immunologic status as well as of virological parameters was performed in nine patients. The results showed a significant clinical improvement in all patients after 4 weeks. A complete regression was observed in 12 patients after the first ECT, while four patients required a second treatment on the residual lesions after 4 weeks from the first intervention. The positive outcome persisted during the subsequent clinical control visits. Two patients, that showed rapidly evolving did not improve and relapsed despite a second round of ECT treatment. Effective treatment was associated with the reduction of viral load to undetectable levels. These data support the conduct of larger studies directed at validating the efficacy of ECT as a first-line therapy for cKS.

Serosurvey against H5 and H7 avian influenza viruses in Italian poultry workers.

Highly pathogenic (HP) and low pathogenic (LP) avian influenza viruses (AIVs) belonging to H5 and H7 subtypes have been found to be associated with human infection as the result of direct transmission from infected poultry. Human infections by AIVs can cause mild or subclinical disease, and serosurveys are believed to represent an important tool to identify risk of zoonotic transmission. Therefore, we sought to examine Italian poultry workers exposed during LPAI and HPAI outbreaks with the aim of assessing serologic evidence of infection with H5 and H7 AIVs. From December 2008 to June 2010 serum samples were collected from 188 poultry workers and 379 nonexposed controls in Northern Italy. The hemagglutination inhibition (HI) assay using horse red blood cells (RBCs) and a microneutralization (MN)-enzyme-linked immunosorbent assay test were used to analyze human sera for antibodies against the following H5 and H7 LPAI viruses: A/Dk/It/4445/07(H5N2); A/Ty/It/2369/09(H5N7); A/Ty/It/218-193/ 10; A/Ck/It/3775/99(H7N1); A/Ty/It/214845/03(H7N3); and A/Dk/It/332145/09(H7N3). Since previous studies identified low antibody titer to AIVs in people exposed to infected poultry, a cutoff titer of > or = 1:10 was chosen for both serologic assays. Only HI-positive results confirmed by MN assay were considered positive for presence of specific antibodies. The Fisher exact test was used to analyze differences in seroprevalence between poultry workers and control groups, with the significance level set at P < 0.05. MN results showed a proportion of H7-seropositive poultry workers (6/188, i.e., 3.2%), significantly higher than that of controls (0/379), whereas no MN-positive result was obtained against three H5 LPAI subtypes recently identified in Italy. In conclusion, the survey indicated that assessing seroprevalence can be an important tool in risk assessment and health,surveillance of poultry workers.

Sexually transmitted diseases syndromic approach: urethral discharge.

Urethral discharge (UD) in men is one of the most identifiable sexually transmitted infections (STI)-associated syndromes. UD performs very well, giving the possibility of an accurate diagnosis, a treatment at first encounter, a rapid cure with effective drugs, a modification of the risk behavior. Furthermore the patient is informed about the infectious nature of STDs, the transmission through sexual intercourse, the increased risks of infertility and other complications and, finally, the importance of completing treatment, even after improvement. Applying the syndromic approach to UD has resulted in effective case management of urethritis, as shown in different studies. Thus, there are numerous reasons why treatment of gonorrhea should include a regimen with complete in vivo activity against both N. gonorrhoeae and C. trachomatis.

Preoperative advantages of HF sonography of pilonidal sinus.

AIM AND METHODS: Pilonidal sinus is a not infrequent disease, probably due to a disontogenetic origin. Histologically, there is a pseudocystic formation in the subcutaneous adipose tissue, containing some hair bulbs. It usually presents a recurring inflammatory course. The pathologic formation does not normally have thick wall, being made up of thin epidermal epithelium, without internal vascularisation and with frequent subcutaneous fistulae. Even though the clinical diagnosis is rather easy, surgery may prove, on the contrary, a demanding task, with a high incidence of recurrence and complications. An adequate knowledge of the condition and its development, with a precise definition of the margins of the lesions, may simplify the surgery, reducing the chance of recurrence or complications. The use of echography in the diagnosis of this disease, in our cohort of 72 patients, has always provided valuable information. In particular, 13 and 18 MHz linear probes and 20 MHz mechanical array have been used, and the latter in particular for the evaluation of fistolous cavities/passageways under the skin. Results. In all our cases, echography has demonstrated pseudocystic formations, without real walls, with fairly high levels of internal echoes, compared to the hair follicles, or, more rarely, true macrocalcifications with one or more cavities/passageways near the skin, without internal vascularisation, according to the histological findings. Echographic data are rapidly obtained, and can prove useful for surgeons for a a better management of patients. Conclusion. We consider diagnostic echography, using high frequency probes, useful for the anatomical definition of this disease, as well as to enable better surgical management.

Stroke unit care in clinical practice: an observational study in the Florence center of the European Registers of Stroke (EROS) Project.

BACKGROUND: Randomized trials and meta-analyses indicate positive effects of stroke unit (SU) care on survival and dependency of patients with stroke. However, data on the advantages of SU in 'real-world' settings are limited. We prospectively assessed, in a large University Hospital, the effect of SU versus other conventional wards (OCW) care on all-cause mortality, death or dependency, death or institutionalization. METHODS: In a prospective observational study in the European Registers of Stroke Project, patients hospitalized for first-in-a-lifetime stroke were evaluated for demographics, risk factors, clinical presentation, resource use, 3-month and 1-year survival, and functional outcome. RESULTS: Overall, 355 patients (54.1% men, mean age 73.4 ± 14.5 years) were registered, 140 (39.4%) admitted to the SU, and 215 (60.6%) to OCW. OCW patients were older, whilst SU patients had more severe strokes according to NIHSS (P for trend = 0.025). SU patients were significantly more often treated by specialists in stroke medicine, stroke nurses, physiotherapists and speech therapists (all P < 0.001), psychologists (P = 0.025), dietitians (P < 0.001), and social workers (P = 0.003). MRI, carotid, and transcranial Doppler were significantly more often performed in SU patients (all P < 0.001). Intravenous fluids (P = 0.003) and intravenous anticoagulation (P < 0.001) were more often prescribed in SU. Controlling for case-mix, SU significantly reduced 1-year mortality (P = 0.020), death or dependency at 3 months (P = 0.006) and 1 year (P = 0.043), and death or institutionalization at 3 months (P = 0.001) and 1 year (P = 0.009). CONCLUSIONS: We confirmed the benefits of SU care in a clinical setting. Further analyses should define the contribution of individual components of care to stroke outcome.

Thermal activation of mass transport and charge transfer at Pt in the I(3)(-)/I(-) electrolyte of a dye-sensitized solar cell.

The electrochemical properties of the I(3)(-)/I(-) reaction mediator as a function of temperature in the range from 30 degrees C to 80 degrees C were investigated by means of symmetric Pt electrodes thin-layer cells (TLC), using three electro-analytical techniques: Electrochemical Impedance Spectroscopy (EIS), Slow Scan Cyclic Voltammetry (SSCV) and Chronoamperometry (CA). Our study pointed out that raising the cell temperature has a beneficial effect both on charge transfer and on mass transport, with an activation energy for the electron transfer process at equilibrium of 24 kJ mol(-1), and of 12 kJ mol(-1) for the mass transfer process at equilibrium. Viscosity and conductivity measurements have demonstrated that most of the ionic mass transport in the solvent (methoxypropionitrile) follows the Stokes' law and that the Walden product is constant, in the temperature range investigated. The diffusion of I(3)(-), however, was found to be partly "non-Stokesian" at lower temperature where the viscosity of the electrolyte is higher. We have shown that EIS and chronoamperometry are both valid methods to derive diffusion coefficients of redox ions in TLC, even if their exact concentration in the electrolyte is not known.