Inhibited coupling guiding hollow fibers for label-free DNA detection

The potentialities in using hollow core tube lattice fibers based on inhibited coupling wave-guiding for label-free DNA detection are numerically investigated and discussed here. The proposed sensing approach does not require any additional transducer component such as Bragg gratings, amplifying techniques such as nanoparticles nor coherent sources. It simply consists of the measurement of the transmittance of a piece of fiber some ten centimeters long. In case of matching DNA sequence, an additional bio-layer is laid down the dielectric-air interface causing a red shift of the transmission spectrum of the fiber. Results show a spectral sensitivity on the bio-layer with shift as high as 42 nm for every 10 nm of bio-layer and robustness against imperfect fiber coupling. The proposed approach can be easily applied to sensing of other complex molecular structures where the presence/absence of analyte can generate or not an additional layer

Compatibility studies between Radio Astronomy and three upcoming technologies

In recent years, the increased use of high-frequency technology in the millimetre and microwave range, including mobile phones, automobiles, and industrial equipment, has further reduced and threatened the spectrum assigned to the radio astronomy service (RAS). As a scientific and passive service, RAS requires protection from commercial services to observe the extremely faint celestial signals. As spectrum use for land, air, and space communications grows, protecting RAS operations from radio frequency interference is becoming more challenging. This report examines the impact of advanced technologies on radio astronomy, specifically car radar at 77 GHz, 5G and Wi-Fi device deployments at 6.6 GHz. These technologies are evaluated for their potential impact on Italian radio telescopes: the Radio Observatories of Medicina and Noto and the Sardinia Radio Telescope (SRT). Of particular concern is the potential threat posed by car radars to future high-density prospects, as well as the historical importance of the 6.6 GHz frequency for radio astronomical observation of methanol emissions from stars

Corrigendum: Analysis of Long-Term Changes in a Mediterranean Marine Ecosystem Based on Fishery Landings

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New Insights in the Setting of Transplant Oncology

: Background and Objectives: Liver transplantation (LT) is the best strategy for curing several primary and secondary hepatic malignancies. In recent years, growing interest has been observed in the enlargement of the transplant oncology indications. This paper aims to review the most recent developments in the setting of LT oncology, with particular attention to LT for unresectable colorectal liver metastases (CRLM) and cholangiocellular carcinoma (CCA). Materials and Methods: A review of the recently published literature was conducted. Results: Growing evidence exists on the efficacy of LT in curing CRLM and peri-hilar and intrahepatic CCA in well-selected patients when integrating this strategy with (neo)-adjuvant chemotherapy, radiotherapy, or locoregional treatments. Conclusion: For unresectable CCA and CRLM management, several prospective protocols are forthcoming to elucidate LT's impact relative to alternative therapies. Advances in diagnosis, treatment protocols, and donor-to-recipient matching are needed to better define the oncological indications for transplantation. Prospective, multicenter trials studying these advances and their impact on outcomes are still required

Hollow-core fibers with reduced surface roughness and ultralow loss in the short-wavelength range

While optical fibers display excellent performances in the infrared, visible and ultraviolet ranges remain poorly addressed by them. Obtaining better fibers for the short-wavelength range has been restricted, in all fiber optics, by scattering processes. In hollow-core fibers, the scattering loss arises from the core roughness and represents the limiting factor in reducing their loss regardless of the fiber cladding confinement power. To attain fibers performing at short wavelengths, it is paramount developing means to minimize the height variations on the fiber microstructure boundaries. Here, we report on the reduction of the core surface roughness of hollow-core fibers by modifying their fabrication technique. In the novel process proposed herein, counter directional gas fluxes are applied within the fiber holes during fabrication to attain an increased shear rate on its microstructure. The effect of the process on the surface roughness has been quantified by optical profilometry and the results showed that the root-mean-square surface roughness has been reduced from 0.40 nm to 0.15 nm. The improvement in the fiber core surface quality entailed fibers with ultralow loss in the short-wavelength range. We report on fibers with record loss values as low as 50 dB/km at 290 nm, 9.7 dB/km at 369 nm, 5.0 dB/km at 480 nm, and 1.8 dB/km at 719 nm. The results reveal this new approach as a promising path for the development of hollow-core fibers guiding at short wavelengths with loss that can potentially be orders of magnitude lower than the ones achievable with their silica-core counterparts

Tailoring modal properties of inhibited-coupling guiding fibers by cladding modification

Understanding cladding properties is crucial for designing microstructured optical fibers. This is particularly acute for Inhibited-Coupling guiding fibers because of the reliance of their core guidance on the core and cladding mode-field overlap integral. Consequently, careful planning of the fiber cladding parameters allows obtaining fibers with optimized characteristics such as low loss and broad transmission bandwidth. In this manuscript, we report on how one can tailor the modal properties of hollow-core photonic crystal fibers by adequately modifying the fiber cladding. We show that the alteration of the position of the tubular fibers cladding tubes can alter the loss hierarchy of the modes in these fibers, and exhibit salient polarization propriety. In this context, we present two fibers with different cladding structures which favor propagation of higher order core modes \u2013 namely LP11 and LP21 modes. Additionally, we provide discussions on mode transformations in these fibers and show that one can obtain uncommon intensity and polarization profiles at the fiber output. This allows the fiber to act as a mode intensity and polarization shaper. We envisage this novel concept can be useful for a variety of applications such as hollow core fiber based atom optics, atom-surface physics, sensing and nonlinear optics

Ecological stages of the Venice Lagoon analysed using landing time series data

The time series of landings in the Venice Lagoon from 1945 to 2001 were analysed with the aim of explaining the ecosystem changes occurred. The comparative analysis of the total landings and mean Trophic Level (mTL) time series allowed to identify four different stages in the lagoon ecosystem. The first period, from 1945 to 1973, was characterised by increasing trends in the landings and their mTL. The second one, from 1974 to 1989, showed a decrease in the landings but still an increase in the mTL. The third period, from 1990 to 1998, had again a positive trend in the landings, but the mTL showed a sharp decline. After 1998, a slight decreasing trend in both mTL and landings was observed: the analyses of the artisanal fishery landings only date back to 1995 this effect. The presence of four distinct periods was also confirmed by the analysis of the trends of other indices estimated using landings data: the Fishing in Balance index (FiB), the Trophic Efficiency (TE) and the Pelagic on Demersal landings ratio (P/D). In the first period, the increasing fishing pressure, along with no evidence of ecosystemcrisis, suggested that an increased nutrient dischargewas supporting it; analogously, the bottom-up effects had driven the dynamics of the ecosystem also in the second period, when the decrease in nutrient loads caused a shift of the primary producers fromplanktonic tomacrobenthic. The spreading of theManila clam, a non-native species, and the development of its massive mechanical exploitation have been the main forces driving the ecosystem during the third period, forwhich, however, no signs of criseswere detected. The fourth period showed evidence of the ‘‘fishing down the food web’’ effect. Possible causes of such an effect were investigated and allowed us to conclude that not overfishing, but the effects ofmechanical harvesting of theManila clamhad caused relevant impacts on habitat and benthic communities, concluding that the present level of exploitation of the stock ofManila clamis not sustainable in the long term. Our findings were also compared with the general evolution of enclosed seas, subjected to high nutrient loads, fishing pressure and invasion by non-native species