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Self-referenced photonic chip soliton Kerr frequency comb

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Light(Science & Applications) 2016年第1期5卷 282-287页

作者： Victor Brasch Erwan Lucas John d Jost michael Geiselmann Tobias J Kippenberg École Polytechnique Fédérale de Lausanne(EPFL)–IPHYS Lausanne CH-1015Switzerland

Self-referencing turns pulsed laser systems into self-referenced frequency *** frequency combs allow counting of optical frequencies and have a wide range of *** required optical bandwidth to implement self-referencing is typically obtained via nonlinear broadening in optical *** advances in the field of Kerr frequency combs have provided a path toward the development of compact frequency comb sources that provide broadband frequency combs,exhibit microwave repetition rates and are compatible with on-chip photonic *** devices have the potential to significantly expand the use of frequency *** to date,self-referencing of such Kerr frequency combs has only been attained by applying conventional,fiber-based broadening *** we demonstrate external broadening-free self-referencing of a Kerr frequency *** optical spectrum spanning two-thirds of an octave is directly synthesized from a continuous wave laser-driven silicon nitride microresonator using temporal dissipative Kerr soliton formation and soliton Cherenkov *** this coherent bandwidth and two continuous wave transfer lasers in a 2f–3f self-referencing scheme,we are able to detect the offset frequency of the soliton Kerr frequency *** stabilizing the repetition rate to a radio frequency reference,the self-referenced frequency comb is used to count and track the continuous wave pump laser’s *** work demonstrates the principal ability of soliton Kerr frequency combs to provide microwave-to-optical clockworks on a chip.

关键词： frequency combs integrated optics Kerr frequency combs metrology microresonator frequency combs nonlinear optics

Optimizing synthesis conditions of nanoscale zero-valent iron （nZVI） through aqueous reactivity assessment

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Frontiers of Environmental Science & Engineering 2015年第5期9卷 813-822页

作者： Yanlai HAN michael d. Y. YANG Weixian ZHANG Weile YAN department of Civil and Environmental Engineering Texas Tech University Lubbock TX 79409 USA State Key Laboratory for Pollution Control & Resources Reuse Tongji University Shanghai 200092 China

Nanoscale iron particles （nZVI） is one of the most important engineered nanomaterials applied to environmental pollution control and abatement. Although a multitude of synthesis approaches have been proposed, a facile method to screen the reactivity of candidate nZVI materials produced using different methods or under varying synthesis conditions has yet been established. In this study, four reaction parameters were adjusted in the preparation of borohydride-reduced nZVI. The reductive properties of the resultant nanoparticles were assayed independently using two model aqueous contaminants, Cu （II） and nitrate. The results confirm that the reductive reactivity of nZVI is most sensitive to the initial concentration of iron precursor, borohydride feed rate, and the loading ratio of borohydride to ferric ion during particle synthesis. Solution mixing speed, in contrast, carries a relative small weight on the reactivity of nZVI. The two probing reactions （i.e., Cu（II） and nitrate reduction） are able to generate consistent and quantitative inference about the mass-normalized surface activity of nZVI. However, the nitrate assay is valid in dilute aqueous solutions only （50 mg.L~ or lower） due to accelerated deactivation of iron surface at elevated nitrate concentra- tions. Additional insights including the structural and chemical makeup of nZVI can be garnered from Cu（II） reduction assessments. The reactivity assays investigated in this study can facilitate screening of candidate materials or optimization of nZVI production parameters, which complement some of the more sophisticated but less chemically specific material characterization methods used in the nZVI research.

关键词： iron nanoparticles nanoscale iron particles(nZVI) synthesis characterization Cu(II) reduction nitratereduction

Recent Advances in the Science of Burst Wave Lithotripsy and Ultrasonic Propulsion

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Biomedical Engineering Frontiers 2022年第1期3卷 48-53页

作者： dima Raskolnikov michael R.Bailey Jonathan d.Harper department of Urology University of Washington School of MedicineSeattleWAUSA Center for Industrial and Medical Ultrasound Applied Physics LaboratoryUniversity of WashingtonSeattleWAUSA

Nephrolithiasis is a common,painful condition that requires surgery in many patients whose stones do not pass *** technologic advances have enabled the use of ultrasonic propulsion to reposition stones within the urinary tract,either to relieve symptoms or facilitate *** wave lithotripsy(BWL)has emerged as a noninvasive technique to fragment stones in awake patients without significant pain or renal *** review the preclinical and human studies that have explored the use of these two *** envision that BWL will fill an unmet need for the noninvasive treatment of patients with nephrolithiasis.

关键词： urinary surgery advances

Apolipoproteins and amyloid fibril formation in atherosclerosis

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Protein & Cell 2011年第2期2卷 116-127页

作者： Chai Lean Teoh michael d.W.Griffin Geoffrey J.Howlett department of Biochemistry and Molecular Biology University of MelbourneParkvilleVictoria 3010Australia Bio21 Molecular Science and Biotechnology InstituteUniversity of MelbourneParkvilleVictoria 3010Australia

Amyloid fibrils arise from the aggregation of misfolded proteins into highly-ordered *** accumulation of these fibrils along with some non-fibrillar constituents within amyloid plaques is associated with the pathogenesis of several human degenerative diseases.A number of plasma apolipoproteins,including apolipoprotein(apo)A-I,apoA-II,apoC-II and apoE are implicated in amyloid formation or influence amyloid formation by other *** review present knowledge of amyloid formation by apolipoproteins in disease,with particular focus on *** insights into the molecular mechanisms underlying their amyloidogenic propensity are obtained from in vitro studies which describe factors affecting apolipoprotein amyloid fibril formation and ***,we outline the evidence that amyloid fibril formation by apolipoproteins might play a role in the development and progression of atherosclerosis,and highlight possible molecular mechanisms that could contribute to the pathogenesis of this disease.

关键词： misfolding apolipoproteins amyloid fibril atherosclerosis

Effects of Nanostructured Back Reflectors on the External Quantum Efficiency in Thin Film Solar Cells

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Nano Research 2011年第2期4卷 153-158页

作者： Chingmei Hsu George F. Burkhard michael d. McGehee Yi Cui department of Materials Science and Engineering Stanford University Stanford California 94305 USA department of Applied Physics Stanlbrd University Stanlbrd California 94305 USA

Hydrogenated amorphous Si （a-Si：H） is a promising material for photovoltaic applications due to its low cost, high abundance, long lifetime, and non-toxicity. We demonstrate a device designed to investigate the effect of nanostructured back reflectors on quantum efficiency in photovoltaic devices. We adopt a superstrate configuration so that we may use conventional industrial light trapping strategies for thin film solar cells as a reference for comparison. We controlled the nanostructure parameters via a wafer-scale self-assembly technique and systematically studied the relation between nanostructure size and photocurrent generation. The gain/loss transition at short wavelengths showed red-shifts with decreasing nanostructure scale. In the infrared region the nanostructured back reflector shows large photocurrent enhancement with a modified feature scale. This device geometry is a useful archetype for investigating absorption enhancement by nanostructures.

关键词： Solar cells back reflector scattering solar energy amorphous silicon

Hospitalization for variceal hemorrhage in an era with more prevalent cirrhosis

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World Journal of Gastroenterology 2014年第32期20卷 11326-11332页

作者： Nicholas Lim michael J desarno Steven d Lidofsky Eric Ganguly division of Gastroenterology and Hepatology University of Vermont College of Medicine Burlington VT 05401 United States department of Biostatistics University of Vermont College of Medicine Burlington VT 05401 United States

AIM: To examine hospitalization rates for variceal hemorrhage and relation to cause of cirrhosis during an era of increased cirrhosis prevalence.

关键词： Varices Gastrointestinal bleeding Cirrhosis Hospitalization Portal hypertension

A review of self-assembled monolayers as potential terahertz frequency tunnel diodes

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Nano Research 2014年第5期7卷 589-625页

作者： michael Celestin Subramanian Krishnan Shekhar Bhansali Elias Stefanakos d. Yogi Goswami department of Chemical & Biomedical Engineering University of South Florida Tampa FL 33520 USA department of Electrical Engineering University of South Florida Tampa FL 33620 USA department of Electrical & Computer Engineering Florida International University Miami FL 33174 USA

In this review, we describe the principles of the tunnel junction, self-assembled monolayer （SAM） application techniques, experimental testbed fabrication, and characterization of the films and devices. In addition, techniques for directed application, removal, and functionalization of the monolayers are discussed. Bottom-up fabrication techniques have seen increased attention because of their versatility and ease of use. These films see mechanical uses as surface modifiers and micro-scale lubricants. Advances in nanowatt electronics and ultra-low power sensors have opened up an energy harvesting niche for solutions which would have proven ineffective just some years ago. The focus of this study is the two- terminal junction which has potential applications in THz rectification for energy harvesting, medical imaging, and defense sensing. The quantum theory of operation behind these devices is touched on briefly---describing tunneling through the organic monolayers. Commentary on trends in research and potential future work are presented as well.

关键词： SAM/self-assembly quantum tunneling molecular rectification IR detection rectenna

Influence of nitrogen sources on growth and mycotoxin production by isolates of Pyrenophora tritici-repentis from wheat

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The Crop Journal 2016年第2期4卷 119-128页

作者： Noureddine Bouras michael d.Holtz Reem Aboukhaddour Stephen E.Strelkov department of Agricultural Food and Nutritional Science410 Agriculture/Forestry CentreUniversity of Alberta Laboratoire de Biologie des Systemes Microbiens(LBSM) Ecole Normale Superieure de KoubaAlgiersAlgeria departement de Biologie Faculte des Sciences de la Nature et de la Vie et Sciences de la TerreUniversite de Ghardaia Field Crop development Centre Alberta Agriculture and Food

The fungus Pyrenophora tritici-repentis(died.) drechs. infects the leaves and kernels of wheat,causing tan spot and red smudge, respectively. Isolates of P. tritici-repentis have been reported to be both phytopathogenic and mycotoxigenic. This research investigates the influence of nitrogen sources on growth and production of mycotoxins by eight different isolates of P. tritici-repentis. A synthetic agar medium(SAM) was used with different nitrogen sources, both inorganic [(NH4Cl, NH4NO3and(NH4)2SO4)] and organic(L-alanine, L-histidine, and L-lysine), at a concentration of 37.5 mmol L-1. Individual isolates exhibited different growth rates that varied according to the nitrogen source added to the medium. The choice of nitrogen source also had a major effect on production of the mycotoxins emodin, catenarin and islandicin. The highest concentrations of emodin, 54.40 ± 4.46 μg g-1, 43.07 ± 23.39 μg g-1and28.91 ± 4.64 μg g-1of growth medium, were produced on the complex medium(V8-potato dextrose agar) by the isolates Alg-H2, 331-2 and TS93-71 B, respectively. A relatively high concentration of emodin also was produced by isolates Az35-5(28.29 ± 4.71 μg g-1of medium)and TS93-71B(27.03 ± 4.09 μg g-1of medium) on synthetic medium supplemented with L-alanine. The highest concentrations of catenarin(174.54 ± 14.46 μg g-1and 104.87 ±6.13 μg g-1of medium) were recorded for isolates TS93-71 B and Alg-H2 on synthetic medium supplemented with L-alanine and NH4 Cl, respectively. The highest concentration of islandicin(4.64 ± 0.36 μg g-1medium) was observed for isolate 331-2 in the presence of L-lysine. There was not a close relationship between mycelial growth and mycotoxin production by the fungal isolates. This is the first report on the influence of nitrogen sources on the production of mycotoxins by P. tritici-repentis.

关键词： Catenarin Emodin Islandicin Nitrogen source Tan spot Triticum aestivum

Interobserver error in grassland vegetation surveys:sources and implications

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Journal of Plant Ecology 2020年第5期13卷 641-648页

作者： Lloyd W.Morrison Sherry A.Leis michael d.deBacker department of Biology Missouri State University901 S.National AvenueSpringfieldMO 65897USA National Park Service Heartland Inventory and Monitoring ProgramWilson’s Creek National Battlefield6424 W.Farm Road 182RepublicMO 65738USA

Aims Observer error is an unavoidable aspect of vegetation surveys involving human *** quantified four components of interobserver error associated with long-term monitoring of prairie vegetation:overlooking error,misidentification error,cautious error and estimation *** also evaluated the association of plot size with pseudoturnover due to observer error,and how documented pseudochanges in species composition and abundance compared with recorded changes in the vegetation over a 4-year *** This study was conducted at Tallgrass Prairie National Preserve,*** sites contained 10 plots;each plot consisted of a series of four nested frames(0.01,0.1,1 and 10 m^(2)).The herbaceous species present were recorded in each of the nested frames,and foliar cover was visually estimated within seven cover categories at the 10 m^(2)spatial scale *** hundred total plots(30 sites)were surveyed,and 28 plots selected at random were resurveyed to assess observer *** surveyors worked in teams of *** Findings At the 10 m^(2)spatial scale,pseudoturnover resulting from overlooking error averaged 18.6%,compared with 1.4%resulting from misidentification error and 0.6%resulting from cautious *** resulting from overlooking error increased as plot size decreased,although relocation error likely played a *** change in species composition over a 4-year interval(excluding potential misidentification error and cautious error)was 30.7%,which encompassed both pseudoturnover due to overlooking error and actual *** a documented overlooking error rate of 18.6%,this suggests the actual change for the 4-year period was only 12.1%.For estimation error,26.2%of the time a different cover class was *** the 4-year interval,46.9%of all records revealed different cover classes,suggesting that 56%of the records of change in cover between the two time periods were due to observer error.

关键词： cautious error estimation error misidentification error observer error overlooking error pseudoturnover