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Mechanisms of enhanced sub-bandgap absorption in high-speed all-silicon avalanche photodiodes

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Photonics Research 2023年第2期11卷 337-346页

作者： YUAN YUAN WAYNE V.SORIN DI LIANG STANLEY CHEUNG YIWEI PENG MUDIT JAIN ZHIHONG HUANG marco fiorentino RAYMOND G.BEAUSOLEIL Hewlett Packard Labs Hewlett Packard EnterpriseMilpitasCalifornia 95035USA

All-silicon (Si) photodiodes have drawn significant interest due to their single and simple material system and perfect compatibility with complementary metal-oxide semiconductor photonics. With the help from a cavity enhancement effect, many of these photodiodes have shown considerably high responsivity at telecommunication wavelengths such as 1310 nm, yet the mechanisms for such high responsivity remain unexplained. In this work,an all-Si microring is studied systematically as a photodiode to unfold the various absorption mechanisms.At-6.4 V, the microring exhibits responsivity up to0.53 A∕W with avalanche gain, a 3 dB bandwidth of25.5 GHz, and open-eye diagrams up to 100 Gb/s. The measured results reveal the hybrid absorption mechanisms inside the device. A comprehensive model is reported to describe its working principle, which can guide future designs and make the all-Si microring photodiode a promising building block in Si photonics.

关键词： Gb/s avalanche absorption

64 Gb/s low-voltage waveguide SiGe avalanche photodiodes with distributed Bragg reflectors

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Photonics Research 2020年第7期8卷 1118-1123页

作者： Binhao Wang Zhihong Huang Yuan Yuan Di Liang Xiaoge Zeng marco fiorentino Raymond G.Beausoleil Hewlett Packard Laboratories Hewlett Packard EnterprisePalo AltoCalifornia 94304USA

We demonstrate low-voltage waveguide silicon-germanium avalanche photodiodes(APDs)integrated with distributed Bragg reflectors(DBRs).The internal quantum efficiency is improved from 60%to 90%at 1550 nm assisted with DBRs while still achieving a 25 GHz bandwidth.A low breakdown voltage of 10 V and a gain bandwidth product of near 500 GHz are obtained.APDs with DBRs at a data rate of 64 Gb/s pulse amplitude modulation with four levels(PAM4)show a 30%–40%increase in optical modulation amplitude(OMA)compared to APDs with no DBR.A sensitivity of around-13 d Bm at a data rate of 64 Gb/s PAM4 and a bit error rate of 2.4×10^-4 is realized for APDs with DBRs,which improves the sensitivity by^2 d B compared to APDs with no DBR.

关键词： Gb/s waveguide avalanche

High speed optical modulation in Ge quantum wells using quantum confined stark effect

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Frontiers of Optoelectronics 2012年第1期5卷 82-89页

作者： Yiwen RONG Yijie HUO Edward T.FE marco fiorentino Michael R.T.TAN Tomasz OCHALSKI Guillaume HUYET Lars THYLEN Marek CHACINSKI Theodore I.KAMINS James S.HARRIS Department of Electrical Engineering Stanford UniversityStanfordCA 94305USA Quantum Science Research Hewlett-Packard LaboratoriesPalo AltoCA 94304USA Tyndall National Institute Lee MaltingsPhotonics BuildingCorkIreland Photonics and Microwave Engineering Royal Institute of Technology Kista Stockholm S-16440Sweden

We focus on the optimization of SiGe material deposition, the minimization of the parasitic capacitance of the probe pads for high speed, low voltage and high contrast ratio operation. The device fabrication is based on processes for standard Si electronics and is suitable for mass-production. We present observations of quantum confinement and quantum-confined Stark effect （QCSE） electroabsorption in Ge quantum wells （QWs） with SiGe barriers grown on Si substrates. Though Ge is an indirect gap semiconductor, the resulting effects are at least as clear and strong as seen in typical III-V QW structures at similar wavelengths. We also demonstrated a modulator, with eye diagrams of up to 3.5 GHz, a small driving voltage of 2.5 V and a modulation bandwidth at about 10 GHz. Finally, carrier dynamics under ultra-fast laser excitation and high- speed photocurrent response are investigated.

关键词： electroabsorption effect Ge optical intercon-nections optical modulators quantum-confined Stark effect（QCSE） Ge/SiGe quantum wells （QWs）

Rare causes of acute non-variceal upper gastrointestinal bleeding: A comprehensive review

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World Journal of Gastroenterology 2023年第27期29卷 4222-4235页

作者： Alberto Martino marco Di Serafino Luigi Orsini Francesco Giurazza Roberto fiorentino Enrico Crolla Severo Campione Carlo Molino Luigia Romano Giovanni Lombardi Department of Gastroenterology and Digestive Endoscopy AORN“Antonio Cardarelli”Naples 80131Italy Department of General and Emergency Radiology AORN“Antonio Cardarelli”Naples 80131Italy Department of Interventional Radiology AORN“Antonio Cardarelli”Naples 80131Italy Department of Oncology AORN“Antonio Cardarelli”Naples 80131Italy Department of Oncological Surgery AORN“Antonio Cardarelli”Naples 80131Italy Department of Pathology AORN“Antonio Cardarelli”Naples 80131Italy

Non-variceal upper gastrointestinal bleeding(NVUGIB)is a common gastroenterological emergency associated with significant morbidity and mortality.Gastroenterologists and other involved clinicians are generally assisted by international guidelines in its management.However,NVUGIB due to peptic ulcer disease only is mainly addressed by current guidelines,with upper gastrointestinal endoscopy being recommended as the gold standard modality for both diagnosis and treatment.Conversely,the management of rare and extraordinary rare causes of NVUGIB is not covered by current guidelines.Given they are frequently lifethreatening conditions,all the involved clinicians,that is emergency physicians,diagnostic and interventional radiologists,surgeons,in addition obviously to gastroenterologists,should be aware of and familiar with their management.Indeed,they typically require a prompt diagnosis and treatment,engaging a dedicated,patient-tailored,multidisciplinary team approach.The aim of our review was to extensively summarize the current evidence with regard to the management of rare and extraordinary rare causes of NVUGIB.

关键词： Gastrointestinal bleeding Upper gastrointestinal bleeding Non-variceal upper gastrointestinal bleeding Rare causes Vascular causes Upper endoscopy

Graphene-Oxide Mediated Chemodivergent Ring-Opening of Cyclobutanols

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Chinese Journal of Chemistry 2023年第11期41卷 1333-1340页

作者： Andrea Brunetti Angela Pintus Lorenzo Lombardi Alessandro Kovtun Federico Mascietti Francesco Bruno Enrico Ravera Manuela Melucci Giulio Bertuzzi marco Bandini Dipartimento di Chimica“Giacomo Ciamician” Alma Mater StudiorumUniversitàdi BolognaVia Selmi 240126BolognaItaly Istituto per la Sintesi e la Fotoreattività(ISOF)–CNR Via Gobetti10140129BolognaItaly Magnetic Resonance Center(CERM) University of FlorenceVia L.Sacconi 650019 Sesto FiorentinoItaly Department of Chemistry“Ugo Schiff” University of FlorenceVia della Lastruccia 350019 Sesto FiorentinoItaly Center for Chemical Catalysis–C3 Alma Mater StudiorumUniversitàdi Bolognavia Selmi 240126BolognaItaly

The chemodivergent ring-opening of cyclobutanols is described under the carbocatalytic assistance of graphene oxide(GO).The protocol enables the synthesis of diversely functionalized dienes or indenes(26 examples)based on the amount of GO employed.Spectroscopic(XPS and ssNMR)as well as experimental investigations revealed a direct involvement of theπ-domains of GO in tuning the stability of carbocationic intermediates during the reaction.

关键词： Carbocatalysis C-C activation Graphene Carbocations Methodology and reactions

Testing visible ozone injury within a Light Exposed Sampling Site as a proxy for ozone risk assessment for European forests

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Journal of Forestry Research 2021年第4期32卷 1351-1359页

作者： Pierre Sicard Yasutomo Hoshika Elisa Carrari Alessandra De marco Elena Paoletti ARGANS 260 route du Pin Montard06410 BiotFrance IRET-CNR Via Madonna del Piano 1050019 Sesto FiorentinoItaly Department of Agriculture FoodEnvironment and Forestry(DAGRI)University of FlorenceFlorenceItaly ENEA Via Anguillarese 30100123 Santa Maria di GaleriaItaly

Biologically meaningful and cost-effective indicators are needed for assessing and monitoring the impacts of tropospheric ozone(0_(3)) on vegetation and are required in Europe by the National Emission Ceilings Directive(2016).However,a clear understanding on the best suited indicators is missing.The MOTTLES(MOnitoring ozone injury for seTTing new critical LEvelS) project set up a new generation network for 0_(3) monitoring in forest plots in order to:1) estimate the stomatal 0_(3) fluxes(Phytotoxic Ozone Dose above a threshold Y of uptake,PODY);and 2) collect visible foliar 0_(3) injury,both within the forest plot(ITP) and along the Light Exposed Sampling Site(LESS) along the forest edge.Nine forest sites at high 0_(3) risk were selected across Italy over 2017-2019 and significant correlations(p <0.05) were found between the percentage of symptomatic plant species within the LESS,and POD1(PODY,with Y=1 nmol 0_(3) m^(-2) s^(-1)) calculated for mixed forest species(r=0.53)and with the occurrence and severity of visible foliar 0_(3) injury on the dominant species in the plots(r=0.65).A generic flux-based critical level for mixed forest species was derived within the LESS and it was recommended using11 mmol m^(-2) POD1 as the critical level for forest protection against 0_(3) injury,similar to the critical level obtained in the ITP(12 mmol m^(-2) POD1).It was concluded that the frequency of symptomatic plant species within a LESS is a suitable and effective plant-response indicator of phytotoxic 0_(3) levels in forest monitoring.LESS is a non-destructive,less complex and less time-consuming approach compared to the ITP for monitoring foliar 0_(3) injury in the long term.Assessing visible foliar 0_(3) injury in the ITP might only underestimate the 0_(3) risk assessment at individual sites.These results are biologically meaningful and useful to monitoring experts and environmental policy makers.

关键词： Cost-effective indicator Forest monitoring Light-Exposed Sampling Site Ozone Phytotoxic ozone dose Visible injury

Effect of ancient Khorasan wheat on gut microbiota,inflammation,and short-chain fatty acid production in patients with fibromyalgia

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World Journal of Gastroenterology 2022年第18期28卷 1965-1980页

作者： Simone Baldi Giuditta Pagliai Monica Dinu Leandro Di Gloria Giulia Nannini Lavinia Curini marco Pallecchi Edda Russo Elena Niccolai Giovanna Danza Stefano Benedettelli Giovanna Ballerini Barbara Colombini Gianluca Bartolucci Matteo Ramazzotti Francesco Sofi Amedeo Amedei Department of Experimental and Clinical Medicine University of FlorenceFlorence 50134Italy Unit of Clinical Nutrition Careggi University HospitalFlorence 50134Italy Department of Neurosciences PsychologyDrug Research and Child HealthSection of Pharmaceutical and Nutraceutical SciencesUniversity of FlorenceSesto Fiorentino 50019Italy Department of Biomedical Experimental and Clinical Sciences“Mario Serio”University of FlorenceFlorence 50134Italy Department of Agriculture FoodEnvironment and ForestryUniversity of FlorenceFlorence 50144Italy Multidisciplinary Center for Pain Therapy Reference Center for FibromyalgiaPiero Palagi HospitalUSL Toscana CentroFlorence 50122Italy SOD of Interdisciplinary Internal Medicine Careggi University HospitalFlorence 50134Italy

BACKGROUND Fibromyalgia(FM)syndrome is mainly characterized by widespread pain,sleeping disorders,fatigue,and cognitive dysfunction.In many cases,gastrointestinal distress is also reported,suggesting the potential pathogenic role of the gut microbiota(GM).The GM is deeply influenced by several environmental factors,especially the diet,and recent findings highlighted significant symptom improvement in FM patients following various nutritional interventions such as vegetarian diet,low-fermentable oligosaccharides,disaccharides,monosaccharides,and polyols based diets,gluten-free diet,and especially an ancient grain supplementation.In particular,a recent study reported that a replacement diet with ancient Khorasan wheat led to an overall improvement in symptom severity of FM patients.AIM To examine the effects of ancient Khorasan wheat on the GM,inflammation,and short-chain fatty acid production in FM patients.METHODS After a 2-wk run-in period,20 FM patients were enrolled in this randomized,double-blind crossover trial.In detail,they were assigned to consume either Khorasan or control wheat products for 8 wk and then,following an 8-wk washout period,crossed.Before and after treatments,GM characterization was performed by 16S rRNA sequencing while the fecal molecular inflammatory response and the short-chain fatty acids(SCFAs)were respectively determined with the Luminex MAGPIX detection system and a mass chromatography-mass spectrometry method.RESULTS The Khorasan wheat replacement diet,in comparison with the control wheat diet,had more positive effects on intestinal microbiota composition and on both the fecal immune and SCFAs profiles such as the significant increase of butyric acid levels(P=0.054),candidatus Saccharibacteria(P=9.95e-06)and Actinobacteria,and the reduction of Enterococcaceae(P=4.97e-04).Moreover,the improvement of various FM symptoms along with the variation of some gut bacteria after the Khorasan wheat diet have been documented;in fact we reported positive correlations between Actinobacteria and

关键词： Fibromialgya Gut microbiota Khorasan wheat Fibromialgya symptoms Ancient wheat

Trends in tropospheric ozone concentrations and forest impact metrics in Europe over the time period 2000–2014

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Journal of Forestry Research 2021年第2期32卷 543-551页

作者： Chiara Proietti Maria Francesca Fornasier Pierre Sicard Alessandro Anav Elena Paoletti Alessandra De marco Italian Institute for Environmental Protection and Research(ISPRA) via Brancati 4800144 RomeItaly ARGANS 260 route du Pin Montard06410 BiotFrance Italian National Agency for New Technologies Energy and the EnvironmentC.R.Casaccia00123 RomeItaly IRET-CNR Via Madonna del Piano 10Florence50019 Sesto FiorentinoItaly

In Europe,tropospheric ozone pollution appears as a major air quality issue,and ozone concentrations remain potentially harmful to vegetation.In this study we compared the trends of two ozone metrics widely used for forests protection in Europe,the AOT40(Accumulated Ozone over Threshold of 40 ppb)which only depends on surface air ozone concentrations,and the Phytotoxic Ozone Dose which is the accumulated ozone uptake through stomata over the growing season,and above a threshold Y of uptake(PODY).By using a chemistry transport model,we found that European-averaged ground-level ozone concentrations(−2%)and AOT40 metric(−26.5%)significantly declined from 2000 to 2014,due to successful control strategies to reduce the emission of ozone precursors in Europe since the early 1990s.In contrast,the stomatal ozone uptake by forests increased from 17.5 to 26.6 mmol O3 m^(−2)despite the reduction in ozone concentrations,leading to an increase of potential ozone damage on plants in Europe.In a climate change context,a biologically-sound stomatal flux-based standard(PODY)as new European legislative standard is needed.

关键词： Tropospheric ozone AOT40 POD Trendm Mann-Kendall test

Strigolactone Analogs as Molecular Probes in Chasing the （SLs） Receptor/s： Design and Synthesis of Fluorescent Labeled Molecules

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Molecular Plant 2013年第1期6卷 113-127页

作者： Cristina Prandi Helena Rosso Beatrice Lace Ernesto G. Occhiatot Alberto Oppedisano Silvia Tabasso Gabriele Alberto marco Blangetti Dipartimento di Chimica-Universita di Torino via R Giuria 7 10127 Torino Italy Dipartimento di Scienze della Vita e Biologia dei Sistemi Viale Mattioli 25 10125 Torino Italy Dipartimento di Chimica 'Ugo Schiff' Universita di Firenze Via della Lastruccia 13 50019 Sesto Fiorentino (FI) Italy School of Chemistry and Chemical Biology University College Dublin Belfield Dublin 4 Ireland

Originally identified as allelochemicals involved in plant-parasite interactions, more recently, Strigolactones （SLs） have been shown to play multiple key roles in the rhizosphere communication between plants and mycorrhizal fungi. Even more recent is the hormonal role ascribed to SLs which broadens the biological impact of these relatively simple molecules. In spite of the crucial and multifaceted biological role of SLs, there are no data on the receptor（s） which bind（s） such active molecules, neither in the producing plants nor in parasitic weeds or AM fungi. Information about the putative receptor of SLs can be gathered by means of structural, molecular, and genetic approaches. Our contribution on this topic is the design and synthesis of fluorescent labeled SL analogs to be used as probes for the detection in vivo of the receptor（s）. Knowledge of the putative receptor structure will boost the research on analogs of the natural substrates as required for agricultural applications.

关键词： strigolactones parasitic weeds mycorrhizal fungi receptor fluorescence.