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All-silicon carrier accumulation modulator based on a lateral metal-oxide-semiconductor capacitor

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Photonics Research 2018年第5期6卷 373-379页

作者： KAPIL DEBNATH DAVID J.THOMSON WEIWEI ZHANG ALI Z.KHOKHAR CALLUM LITTLEJOHNS JAMES BYERS lorenzo mastronardi MUHAMMAD K.HUSAIN KOUTA IBUKURO FREOERIC Y.GARDES GRAHAM T,REED SHINICHI SAITO Optoelectronics Research Centre University of SouthamptonSouthampton S017 1B JUK Faculty of Physical Sciences and Engineering University of SouthamptonSouthampton SO17 1BJUK

In silicon photonics, the carrier depletion scheme has been the most commonly used mechanism for demonstrat- ing high-speed electro-optic modulation. However, in terms of phase modulation efficiency, carrier- accumnlation-based devices potentially offer almost an order of carrier depletion. Previously reported accumulation modulator magnitude improvement over those based on designs only considered vertical metal-oxide- semiconductor （MOS） capacitors, which imposes serious restrictions on the design flexibility and integratability with other photonic components. In this work, for the first time to our knowledge, we report experimental demonstration of an all-silicon accumulation phase modulator based on a lateral MOS capacitor. Using a Mach-Zehnder interferometer modulator with a 500-μm-long phase shifter, we demonstrate high-speed modulation up to 25 Gbit/s with a modulation efficiency （V πLπ） of 1.53 V·cm.

关键词： All-silicon carrier accumulation modulator a lateral metal-oxide-semiconductor capacitor

High-efficiency reflector-less dual-level silicon photonic grating coupler

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Photonics Research 2023年第7期11卷 1275-1283页

作者： VALERIO VITALI THALíA DOMíNGUEZ BUCIO COSIMO LACAVA RICCARDO MARCHETTI lorenzo MASTRONAR TEERAPAT RUTIRAWUT GLENN CHURCHILL JOAQUíN FANECA JAMES C.GATES FREDERIC GARDES PERIKLIS PETROPOULOS Optoelectronics Research Centre University of SouthamptonSouthamptonSO171BJUK Electrical Computer and Biomedical Engineering DepartmentUniversity of Pavia27100 PaviaItaly Advanced Fiber Resources Milan S.r.l. 20098 San Donato MilaneseItaly Currently at Instituto de Microelectrónica de Barcelona IMB-CNM(CSIC)Campus UAB08193 BellaterraSpain

We present the design and experimentally demonstrate a dual-level grating coupler with subdecibel efficiency for a 220 nm thick silicon photonics waveguide which was fabricated starting from a 340 nm silicon-on-insulator *** proposed device consists of two grating levels designed with two different linear apodizations,with opposite chirping signs,and whose period is varied for each scattering unit.A coupling efficiency of-0.8 d B at1550 nm is experimentally demonstrated,which represents the highest efficiency ever reported in the telecommunications C-band in a single-layer silicon grating structure without the use of any backreflector or indexmatching material between the fiber and the grating.

关键词： waveguide scattering grating

Spectroscopic detection of forest diseases:a review(1970–2020)

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Journal of Forestry Research 2022年第1期33卷 21-38页

作者： lorenzo Cotrozzi Department of Agriculture Food and EnvironmentUniversity of PisaVia del Borghetto 8056124 PisaItaly

Sustainable forest management is essential to confront the detrimental impacts of diseases on forest *** review highlights the potential of vegetation spectroscopy in improving the feasibility of assessing forest disturbances induced by diseases in a timely and cost-effective *** basic concepts of vegetation spectroscopy and its application in phytopathology are first outlined then the literature on the topic is *** several optical sensors from leaf to landscape-level,a number of forest diseases characterized by variable pathogenic processes have been detected,identified and quantified in many country sites ***,these reviewed studies have pointed out the green and red regions of the visible spectrum,the red-edge and the early near-infrared as the spectral regions most sensitive to the disease development as they are mostly related to chlorophyll changes and symptom *** disease conditions particularly affect the shortwave-infrared region,mostly related to water *** review also highlights some major issues to be addressed such as the need to explore other major forest diseases and geographic areas,to further develop hyperspectral sensors for early detection and discrimination of forest disturbances,to improve devices for remote sensing,to implement longterm monitoring,and to advance algorithms for exploitation of spectral *** of these goals will enhance the capability of vegetation spectroscopy in early detection of forest stress and in managing forest diseases.

关键词： Forest management Plant disease detection Refectance Remote sensing Spectral imaging

Silicon nanocrystals to enable silicon photonics

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Chinese Optics Letters 2009年第4期7卷 319-324页

作者： lorenzo Pavesi Nanoscience Laboratory Department of PhysicsUniversity of Trento

Low dimensional silicon, where quantum size effects play significant roles, enables silicon with new photonic functionalities. In this short review, we discuss the way that silicon nanocrystals are produced, their optoelectronic properties and a few device applications. We demonstrate that low dimensional silicon is an optimum material for developing silicon photonics.

关键词： Nanocrystals Photonic devices

Growth associated protein 43 and neurofilament immunolabeling in the transected lumbar spinal cord of lizard indicates limited axonal regeneration

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Neural Regeneration Research 2022年第5期17卷 1034-1041页

作者： lorenzo Alibardi Comparative Histolab Padova and Department of Biology University of BolognaBolognaItaly

Previous cytological studies on the transected lumbar spinal cord of lizards have shown the presence of differentiating glial cells,few neurons and axons in the bridge region between the proximal and distal stumps of the spinal cord in some cases.A limited number of axons(20-50)can cross the bridge and re-connect the caudal stump of the spinal cord with small neurons located in the rostral stump of the spinal *** axonal regeneration appears to be related to the recovery of hind-limb movements after initial *** present study extends previous studies and shows that after transection of the lumbar spinal cord in lizards,a glial-connective tissue bridge that reconnects the rostral and caudal stumps of the interrupted spinal cord is formed at 11-34 days *** an initial paralysis some recovery of hindlimb movements occurs within 1-3 months *** and ultrastructural analysis for a growth associated protein 43(GAP-43)of 48-50 k Da shows that sparse GAP-43 positive axons are present in the proximal stump of the spinal cord but their number decreased in the bridge at 11-34 days *** immunolabeled axons with a neurofilament protein of 200-220 k Da were seen in the bridge at 11-22 days post-transection but their number increased at 34 days and 3 months post-amputation in lizards that have recovered some hindlimb *** neurons in the rostral and caudal stumps of the spinal cord were also labeled for GAP43,a cytoplasmic protein that is trans-located into their axonal growth *** indicates that GAP-43 biosynthesis is related to axonal regeneration and sprouting from neurons that were damaged by the *** together,previous studies that utilized tract-tracing technique to label the present observations confirm that a limited axonal re-connection of the transected spinal cord occurs 1-3 months post-injury in *** few regenerating-sprouting axons within the bridge reconnect

关键词： GAP-43 immunocytochemistry lizard neurofilaments regeneration spinal cord

Brain network modulation in Alzheimer’s disease:clinical phenotypes and windows of opportunity

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Neural Regeneration Research 2023年第1期18卷 115-116页

作者： lorenzo Pini Padova Neuroscience Center University of PadovaPadovaItaly

Dementia,for which there is no cure or effective treatment,is the leading cause of disability and death *** to the high global prevalence and economic impact on families,caregivers,and communities,this condition represents one of the most significant public health challenges of our *** is an umbrella term describing a range of progressive neurodegenerative diseases,including Alzheimer’s disease(AD),which is the most common cause of cognitive and functional impairment among older *** presence of misfolded protein aggregates characterizes neurodegenerative disorders(e.g.,amyloid-beta(Aβ)and tau in AD).

关键词： Alzheimer Aβ death tau

Immunodetection of ephrin receptors in the regenerating tail of the lizard Podarcis muralis suggests stimulation of differentiation and muscle segmentation

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Zoological Research 2019年第5期40卷 416-426页

作者： lorenzo Alibardi Comparative Histolab Padova and Department of Biology University of Bologna

Ephrin receptors are the most common tyrosine kinase effectors operating during development. Ephrin receptor genes are reported to be up-regulated in the regenerating tail of the Podarcis muralis lizard. Thus, in the current study, we investigated immunolocalization of ephrin receptors in the Podarcis muralis tail during regeneration. Weak immunolabelled bands for ephrin receptors were detected at 15–17 kDa, with a stronger band also detected at 60–65 kDa. Labelled cells and nuclei were seen in the basal layer of the apical wound epidermis and ependyma, two key tissues stimulating tail regeneration. Strong nuclear and cytoplasmic labelling were present in the segmental muscles of the regenerating tail, sparse blood vessels, and perichondrium of regenerating cartilage. The immunolocalization of ephrin receptors in muscle that gives rise to large portions of new tail tissue was correlated with their segmentation. This study suggests that the high localization of ephrin receptors in differentiating epidermis, ependyma, muscle, and cartilaginous cells is connected to the regulation of cell proliferation through the activation of programs for cell differentiation in the proximal regions of the regenerating tail. The lower immunolabelling of ephrin receptors in the apical blastema, where signaling proteins stimulating cell proliferation are instead present, helps maintain the continuous growth of this region.

关键词： Lizard Regenerating blastema Ephrin receptors Immunolabelling Western blotting

Tail regeneration reduction in lizards after repetitive amputation or cauterization reflects an increase of immune cells in blastemas

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Zoological Research 2018年第6期39卷 413-423页

作者： lorenzo Alibardi Comparative Histolab Padua Department of BiologyUniversity of Bologna

Lizards are key amniote models for studying organ regeneration. During tail regeneration in lizards, blastemas contain sparse granulocytes, macrophages, and lymphocytes among the prevalent mesenchymal cells. Using transmission electron microscopy to examine scarring blastemas after third and fourth sequential tail amputations, the number of granulocytes, macrophages, and lymphocytes increased at 3-4 weeks in comparison to the first regeneration. An increase in granulocytes and agranulocytes also occurred within a week after blastema cauterization during the process of scarring Blood at the third and fourth regeneration also showed a significant increase in white blood cells compared with that under normal conditions and at the first regeneration. The extracellular matrix of the scarring blastema, especially after cauterization, was denser than that in the normal blastema and numerous white blood cells and fibroblasts were surrounded by electron-pale, fine fibrinoid material mixed with variable collagen fibrils. In addition to previous studies, the present observations support the hypothesis that an increase in inflammation and immune reactions determine scarring rather than regeneration. These new findings verify that an immune reaction against mesenchymal and epidermal cells of the regenerative blastema is one of the main causes for the failure of organ regeneration in amniotes.

关键词： Lizard Tail Repetitive regeneration Blood Immune cells Ultrastructure

Human Mobility in the Sendai Framework for Disaster Risk Reduction

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International Journal of Disaster Risk Science 2016年第1期7卷 30-40页

作者： lorenzo Guadagno Department of Operations and Emergencies International Organization for Migration(IOM)

This article looks at how population movements are addressed by the Sendai Framework for Disaster Risk Reduction 2015–2030(SFDRR), and highlights some of the potential implications of the SFDRR on disaster risk reduction(DRR) and mobility management work. The article looks at the operational implications of the SFDRR text and covers issues of including migrants in DRR work;informing urban development about current and future mobility trends; managing relocations, evacuations, and displacement to prevent future risks and reduce existing ones; and preparing for and managing disaster-induced population movements to reduce the direct and indirect impacts of natural hazards. Overall, the references to human mobility within the SFDRR show an evolution in the way the issue is considered within global policy dialogues. Both the potential of population movements to produce risk and their role in strengthening the resilience of people and communities are now clearly recognized. This is an evolution of previously prevailing views of mobility as the consequence of disasters or as a driver of risk. While some implications of the DRR-mobility nexus might still be missing from DRR policy, population movements are now recognized as a key global risk dynamic.

关键词： Disaster risk reduction Displacement Human mobility Migration Relocation Sendai framework for disaster risk reduction