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In Free Space Optical (FSO) communication systems, atmospheric turbulence distorts the propagating beams, causing a random fading in the received power. This perturbation can be compensated using a multi-aperture receiver that samples the distorted wavefront on different points and adds the various signals coherently. In this work, we report on an adaptive optical receiver that compensates in real time for scintillation in FSO links. The optical front-end of the receiver is entirely integrated in a silicon photonic chip hosting a 2D Optical Antenna Array and a self-adaptive analog Programmable Optical Processor made of a mesh of tunable Mach-Zehnder interferometers. The photonic chip acts as an adaptive interface to couple turbulent FSO beams to single-mode guided optics, enabling energy and cost-effective operation, scalability to systems with a larger number of apertures, modulation-format and data-protocol transparency, and pluggability with commercial fiber optics transceivers. Experimental results demonstrate the effectiveness of the proposed receiver with optical signals at a data rate of 10 Gbit/s transmitted in indoor FSO links where different turbulent conditions, even stronger than those expected in outdoor links of hundreds of meters, are reproduced., (© 2024. The Author(s).)

Continuously variable true-time optical delay lines are typically subject to a constraint of the bandwidth-delay product, limiting their use in several applications. In this Letter, we propose an integrated topology that breaks the bandwidth-delay product limit. The device is based on multiple Mach-Zehnder Interferometers (MZIs) arranged in parallel, providing easier control and a larger bandwidth compared to ring resonator-based solutions. The functionality of this architecture is demonstrated with a 4-stage delay line by performing measurements in both the time and frequency domains. The delay line introduces a delay of 90 ps over a bandwidth of more than 22 GHz with a negligible group delay distortion, operates on a wavelength range of about 60 nm, and is scalable to a higher number of MZI stages.

We demonstrate a temperature and wavelength shift resilient silicon transmission and routing interconnect system suitable for multi-socket interconnects, utilizing a dual-strategy CLIPP feedback circuitry that safeguards the operating point of the constituent photonic building blocks along the entire on-chip transmission-multiplexing-routing chain. The control circuit leverages a novel control power-independent and calibration-free locking strategy that exploits the 2 nd derivative of ring resonator modulators (RMs) transfer function to lock them close to the point of minimum transmission penalty. The system performance was evaluated on an integrated Silicon Photonics 2-socket demonstrator, enforcing control over a chain of RM-MUX-AWGR resonant structures and stressed against thermal and wavelength shift perturbations. The thermal and wavelength stress tests ranged from 27°C to 36°C and 1309.90 nm to 1310.85 nm and revealed average eye diagrams Q-factor values of 5.8 and 5.9 respectively, validating the system robustness to unstable environments and fabrication variations.

Free-space optics naturally offers multiple-channel communications and sensing exploitable in many applications. The different optical beams will, however, generally be overlapping at the receiver, and, especially with atmospheric turbulence or other scattering or aberrations, the arriving beam shapes may not even be known in advance. We show that such beams can be still separated in the optical domain, and simultaneously detected with negligible cross-talk, even if they share the same wavelength and polarization, and even with unknown arriving beam shapes. The kernel of the adaptive multibeam receiver presented in this work is a programmable integrated photonic processor that is coupled to free-space beams through a two-dimensional array of optical antennas. We demonstrate separation of beam pairs arriving from different directions, with overlapping spatial modes in the same direction, and even with mixing between the beams deliberately added in the path. With the circuit's optical bandwidth of more than 40 nm, this approach offers an enabling technology for the evolution of FSO from single-beam to multibeam space-division multiplexed systems in a perturbed environment, which has been a game-changing transition in fiber-optic systems., (© 2022. The Author(s).)

On-chip optical power monitors are essential elements to calibrate, stabilize, and reconfigure photonic integrated circuits. Many applications require in-line waveguide detectors, where a trade-off has to be found between large sensitivity and high transparency to the guided light. In this work, we demonstrate a transparent photoconductor integrated on standard low-doped silicon-on-insulator waveguides that reaches a photoconductive gain of more than 10 6 and an in-line sensitivity as high as -60 dBm. This performance is achieved by compensating the effect of electric charges in the cladding oxide through a bias voltage applied to the chip substrate or locally through a gate electrode on top of the waveguide, allowing one to tune on demand the conductivity of the core to the optimum level.

Flexible optical networks require reconfigurable devices with operation on a wavelength range of several tens of nanometers, hitless tuneability (i.e. transparency to other channels during reconfiguration), and polarization independence. All these requirements have not been achieved yet in a single photonic integrated device and this is the reason why the potential of integrated photonics is still largely unexploited in the nodes of optical communication networks. Here we report on a fully-reconfigurable add-drop silicon photonic filter, which can be tuned well beyond the extended C-band (almost 100 nm) in a complete hitless (>35 dB channel isolation) and polarization transparent (1.2 dB polarization dependent loss) way. This achievement is the result of blended strategies applied to the design, calibration, tuning and control of the device. Transmission quality assessment on dual polarization 100 Gbit/s (QPSK) and 200 Gbit/s (16-QAM) signals demonstrates the suitability for dynamic bandwidth allocation in core networks, backhaul networks, intra- and inter-datacenter interconnects., (© 2021. The Author(s).)

Objective: To evaluate the efficacy of visual inspection with acetic acid (VIA) screening combined with a cervical smear in Uganda., Methods: Nine screening campaigns were held in Uganda between January 2011 and October 2019. In the last three campaigns, a new approach was used: the cervical smear was performed before the VIA test and, in case of a positive VIA test, the slide was sent for examination. The data collected were divided into two groups: the first six campaigns and the last three campaigns., Results: During the study period, 10 520 women were screened, of whom 911 had a positive VIA test. The VIA test showed 84.2% false positives. In the first group, the VIA test was positive in 516 women, of whom 93% were referred for further examinations. In the second group, the VIA test was positive in 395 women, but the cervical smear was positive in only 65 women. Thus, only 16.5% women were referred for further examinations., Conclusion: Combining cervical smear, VIA test, and slide analysis in positive VIA tests may allow women who need treatment to be selected more effectively, while waiting for other more expensive solutions to become more affordable for this setting., (© 2020 International Federation of Gynecology and Obstetrics.)

Many optoelectronic devices embedded in a silicon photonic chip, like photodetectors, modulators, and attenuators, rely on waveguide doping for their operation. However, the doping level of a waveguide is not always reflecting in an equal amount of free carriers available for conduction because of the charges and trap energy states inevitably present at the S i / S i O 2 interface. In a silicon-on-insulator technology with 10 15 c m -3 p -doped native waveguides, this can lead to a complete depletion of the core from free carriers and to a consequently very high electrical resistance. This Letter experimentally quantifies this effect and shows how the amount of free carriers in a waveguide can be modified and restored to the original doping value with a proper control of the chip substrate potential. A similar capability is also demonstrated by means of a specific metal gate integrated above the waveguide that allows fine control of the conductance with high locality level. This paper highlights the linearity achievable in the conductance modulation that can be exploited in a number of possible applications.

Background: The coronavirus disease 2019 (COVID-19) is currently rare in children and they seem to have a milder disease course and better prognosis than adults. However, SARS-Cov-2 pandemic has indirectly caused problems in pediatric medical assistance. In view of this we wanted to draw a picture of what happened during health emergency and analyze future prospects for restarting., Methods: We involved the Italian pediatric scientific societies institutionally collected in the Italian Federation of Associations and Scientific Societies of the Pediatric Area (FIARPED); We sent a questionnaire to all scientific societies about the pediatric care activity during the COVID-19 emergency and future perspectives for the phase of post-containment., Results: The analysis of the questionnaires showed significant decrease of:admission, outpatient visits and specialist consultancy activities during the COVID-19 emergency, primarily linked to the fear of infection. Instead it was increased the serious degree of diseases admitted. Most of scientific societies maintained the relationship with chronic patients through some form of telemedicine, reporting a strong positive opinion about this modality. Finally showed the need to give life a new approach for hospitalizations and outpatient visits through a greater use of telemedicine, educational programs on families and a more decisive role of family pediatricians., Conclusions: Our study highlighted many aspects that can be improved in pediatric care. We think that It will be necessary a new shared strategy to improve the management and continuity of care for pediatric patients, primarily developing a network of collaboration between families, family pediatrician and hospitals and by enhancing the use of new methods of telecommunications.

A smart, safe, and efficient management of water is fundamental for both developed and developing countries. Several wireless sensor networks have been proposed for real-time monitoring of drinking water quantity and quality, both in the environment and in pipelines. However, surface fouling significantly affects the long-term reliability of pipes and sensors installed in-line. To address this relevant issue, we presented a multi-parameter sensing node embedding a miniaturized slime monitor able to estimate the micrometric thickness and type of slime. The measurement of thin deposits in pipes is descriptive of water biological and chemical stability and enables early warning functions, predictive maintenance, and more efficient management processes. After the description of the sensing node, the related electronics, and the data processing strategies, we presented the results of a two-month validation in the field of a three-node pilot network. Furthermore, self-powering by means of direct energy harvesting from the water flowing through the sensing node was also demonstrated. The robustness and low cost of this solution enable its upscaling to larger monitoring networks, paving the way to water monitoring with unprecedented spatio-temporal resolution.

Background: Young children's healthy development depends on nurturing care, which ensures health, nutrition, responsive caregiving, safety and security, and early learning. Infancy and childhood are characterized by rapid growth and development, and these two factors contribute largely to determining health status and well-being across the lifespan. Identification of modifiable risk factors and prognostic factors during the critical periods of life will contribute to the development of effective prevention and intervention strategies. The NASCITA (NAscere e creSCere in ITAlia) study was created to evaluate physical, cognitive, and psychological development, health status and health resource utilization during the first six years of life in a cohort of newborns, and to evaluate potential associated factors., Methods: NASCITA is an ongoing, dynamic, prospective, population-based birth cohort study of an expected number of more than 5000 newborns who will be recruited in 22 national geographic clusters starting in 2019. It was designed to follow children from birth to school entry age for a wide range of determinants, disorders, and diseases. Recruitment of the newborns (and their parents) will take place during the first routine well-child visit, which takes place at the office of the pediatrician assigned to them by the local health unit of residence, and which is scheduled for all newborns born in Italy within the first 45 days of their life. Data will be web-based and collected by the family pediatricians during each of the 7 standard well-child visits scheduled for all children during their first 6 years of life. Information on every contact with the enrolled children in addition to these prescheduled visits will be also recorded., Discussion: The NASCITA cohort study provides a framework in which children are followed from birth to six-years of age. NASCITA will broaden our understanding of the contribution of early-life factors to infant and child health and development. NASCITA provides opportunities to initiate new studies, also experimental ones, in parts of the cohort, and will contribute relevant information on determinants and health outcomes to policy and decision makers. Cohort details can be found on https://coortenascita.marionegri.it., Trial Registration: Clinicaltrials.gov: NCT03894566. Ethics committee approval: 6 February 2019, Verbale N 59.

To describe the infant feeding practices in the general population in Uganda, and to assess the impact of maternal HIV status on these practices, a questionnaire was administered to women attending the follow-up clinics for child vaccination. Among the mothers who were still breastfeeding at the time of interview (N=838), 61.4% of the HIV-infected women had planned to breastfeed for a maximum of 6 months, compared with 12.1% of the HIV-uninfected women (p<0.001). Among the women who were not breastfeeding at the time of interview (N=108), 82.5% of the HIV-infected women had stopped breastfeeding within 3 months, compared with 23.5% of the HIV-uninfected women (p<0.001). Only 2.1% of HIV-infected women seen up to 14 weeks postnatally practised mixed feeding, compared with 23.6% of HIV-uninfected women (p<0.001). After 6 months, however, 30% of the HIV-infected women and 55% of the HIV-uninfected mothers were using mixed feeding, with no significant differences. Programmes for the prevention of mother-to-child transmission of HIV should re-enforce counseling activities to address the issue of early weaning by HIV-infected women, and to support safe breastfeeding up to 6 months.

Background: Placental site trophoblastic tumor (PSTT) is a rare form of gestational trophoblastic neoplasia, commonly insensitive to chemotherapeutic agents., Case: We report on long-term remission in a patient with metastatic PSTT after etoposide, methotrexate, actinomycin D, cyclophosphamide and vincristine combination chemotherapy. The 27-year-old patient with metastatic lung PSTT was alive, without evidence of disease, > 40 months after treatment., Conclusion: Treatment with multiagent chemotherapy can produce long-term remission, even in patients with metastatic PSTT.

145 children with acute lymphoblastic leukaemia (ALL) were evaluated over a period of 3 years in a multicentre study in which serial cranial computed tomographic (CT) scans of the brain were done. All patients were symptom-free. CT scans were graded as normal, borderline (slight or moderate cerebral atrophy), or pathological (severe cerebral atrophy). 62% (90/145) of children had CT scan abnormalities at diagnosis. After a median follow-up of 24 months (range 6-36) 12 of 108 evaluable patients had central nervous system (CNS) relapses (6 isolated relapses and 6 combined with relapse at another site). All patients with CNS relapse had an abnormal CT scan at diagnosis (8 pathological and 4 borderline). No relapses were observed among the 42 patients with a normal cranial CT scan at diagnosis. A significantly higher proportion of severe cerebral atrophy, both following CNS prophylaxis and after the discontinuation of treatment, was found among patients with a borderline CT scan at diagnosis than among patients with a normal CT scan at diagnosis. Thus an abnormal cranial CT scan at diagnosis in children with ALL seems to have prognostic significance.

Forty children newly diagnosed with acute lymphoblastic leukemia (ALL) were examined by computed tomography (CT) of the central nervous system (CNS) on hospital admission before any medication was started. The results of the CT scans were defined as normal, borderline (slight or moderate dilatation of the ventricular system and/or basal cisterns and/or convolutional sulci), or pathologic (severe cerebral atrophy). The mean age of the patients was 5.8 years (range 1.7-15 years). Sixteen of the 40 patients (40%) had CT scan abnormalities with 14 patients having borderline scans and two patients pathologic scans. No child presented with neurologic symptoms or CNS leukemia. These data suggest that CT abnormalities of the brain are common in children with ALL at diagnosis and may represent clinically unsuspected lesions secondary to leukemia.