Light-directed writing of chemically tunable narrow-band holographic sensors

This tunable holographic sensor offers interrogation and a reporting transducer as well as an analyte-responsive hydrogel, rendering it label-free and reusable. A single 6 ns laser pulse is used to fabricate holographic sensors consisting of silver nanoparticles arranged periodically within a polymer film. The tunability of the sensor is demonstrated through pH sensing of artificial urine and validated through computational modeling. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Computational modelling and characterisation of nanoparticle-based tuneable photonic crystal sensors

Photonic crystals are materials that are used to control or manipulate the propagation of light through a medium for a desired application. Common fabrication methods to prepare photonic crystals are both costly and intricate. However, through a cost-effective laser-induced photochemical patterning, one-dimensional responsive and tuneable photonic crystals can easily be fabricated. These structures act as optical transducers and respond to external stimuli. These photonic crystals are generally made of a responsive hydrogel that can host metallic nanoparticles in the form of arrays. The hydrogel-based photonic crystal has the capability to alter its periodicity in situ but also recover its initial geometrical dimensions, thereby rendering it fully reversible and reusable. Such responsive photonic crystals have applications in various responsive and tuneable optical devices. In this study, we fabricated a pH-sensitive photonic crystal sensor through photochemical patterning and demonstrated computational simulations of the sensor through a finite element modelling technique in order to analyse its optical properties on varying the pattern and characteristics of the nanoparticle arrays within the responsive hydrogel matrix. Both simulations and experimental results show the wavelength tuneability of the sensor with good agreement. Various factors, including nanoparticle size and distribution within the hydrogel-based responsive matrices that directly affect the performance of the sensors, are also studied computationally. © 2014 The Royal Society of Chemistry.

Pulsed laser writing of holographic nanosensors

Tuneable optical sensors have been developed to sense chemical stimuli for a range of applications from bioprocess and environmental monitoring to medical diagnostics. Here, we present a porphyrin-functionalised optical sensor based on a holographic grating. The holographic sensor fulfils two key sensing functions simultaneously: it responds to external stimuli and serves as an optical transducer in the visible region of the spectrum. The sensor was fabricated via a 6 nanosecond-pulsed laser (350 mJ, λ = 532 nm) photochemical patterning process that enabled a facile fabrication. A novel porphyrin derivative was synthesised to function as the crosslinker of a polymer matrix, the light-absorbing material, the component of a diffraction grating, as well as the cation chelating agent in the sensor. The use of this multifunctional porphyrin permitted two-step fabrication of a narrow-band light diffracting photonic sensing structure. The resulting structure can be tuned finely to diffract narrow-band light based on the changes in the fringe spacing within the polymer and the system's overall index of refraction. We show the utility of the sensor by demonstrating its reversible colorimetric tuneability in response to variation in concentrations of organic solvents and metal cations (Cu 2+ and Fe2+) in the visible region of the spectrum (λmax ≈ 520-680 nm) with a response time within 50 s. Porphyrin-functionalised optical sensors offer great promise in fields varying from environmental monitoring to biochemical sensing to printable optical devices. This journal is © the Partner Organisations 2014.

Reusable, robust, and accurate laser-generated photonic nanosensor.

Developing noninvasive and accurate diagnostics that are easily manufactured, robust, and reusable will provide monitoring of high-risk individuals in any clinical or point-of-care environment. We have developed a clinically relevant optical glucose nanosensor that can be reused at least 400 times without a compromise in accuracy. The use of a single 6 ns laser (λ = 532 nm, 200 mJ) pulse rapidly produced off-axis Bragg diffraction gratings consisting of ordered silver nanoparticles embedded within a phenylboronic acid-functionalized hydrogel. This sensor exhibited reversible large wavelength shifts and diffracted the spectrum of narrow-band light over the wavelength range λpeak ≈ 510-1100 nm. The experimental sensitivity of the sensor permits diagnosis of glucosuria in the urine samples of diabetic patients with an improved performance compared to commercial high-throughput urinalysis devices. The sensor response was achieved within 5 min, reset to baseline in ∼10 s. It is anticipated that this sensing platform will have implications for the development of reusable, equipment-free colorimetric point-of-care diagnostic devices for diabetes screening.

半导体异质结及其在光电子学中的应用-2000年诺贝尔物理奖评述

瑞典皇家科学院2000年10月10日宣布，将2000年诺贝尔物理奖授予三位科学家，他们是俄罗斯科学院圣彼得堡约飞技术物理研究所的Zh.I.Alferov、美国加利福尼亚大学的Herbert Kroemer和美国德克萨斯仪器公司的Jack S.Kiby，以表彰他们为现代信息技术，特别是他们发明的高速晶体管、激光二极管和集成电路(芯片)所作出的奠基性贡献。Kilby由于发明并发展了集成电路技术而获奖，通过这项发明，微电子学成为所有现代技术的基础。Kilby的获奖成果已有另文(见2000年第3期《物理》)评述。Alferov和Kromer则是由于他们在半导体异质结及其在电子和光电学中的应用方面的突出贡献则获奖。该文仅就这两位诺贝尔物理奖得主在异质结及其在光电子中的应用方面的贡献进行评述。

长白山森林生态系统中的稀有和濒危多孔菌

In last 10 years,extensive field inventories were carried out to investigate Polypore species, the major wood decaying fungi in the Changbaishan Nature Reserve of Northeastern China. The following 27 species were treated as rare or threathened species: Amylocystis lapponica (Romell) Singer, Anomoporia albolutescens (Romell) Pouzar, Anomoporia bombycina (Fr.) Pouzar, Anomoporia vesiculosa Y.C. Dai & Niemel, Antrodia carbonica (Overh.) Ryvarden & Gilb., Antrodia crassa (P. Karst.) Ryvarden, Antrodiella citrinella Niemel & Ryvarden, Diplomitoporus flavescens (Bres.) Dománski, Donkioporia expansa (Desm.) Kotl. & Pouzar, Gloeophyllum carbonarium (Berk. & M.A. Curtis) Ryvarden, Haploporus odorus (Sommerf.) Bondartsev & Singer, Inonotopsis subiculosa (Peck) Parmasto, Nigroporus ussuriensis (Bondartsev & Ljub.) Y.C. Dai & Niemela, Oxyporus sinensis X.L. Zeng, Parmastomyces taxi (Bondartsev) Y.C. Dai & Niemela, Phellinidium sulphurascens (Pilat) Y.C. Dai, Phellinus vaninii Ljub., Polyporus vassilievae Thorn, Pycnoporellus fulgens (Fr.) Donk, Skeletocutis brevispora Niemela, Skeletocutis ochroalba Niemela, Skeletocutis perennis Ryvarden, Trechispora candidissima (Schwein.) Bondartsev & Singer, Wolfiporia dilatohypha Ryvarden & Gilb., Wolfiporia curvispora Y.C. Dai, Wrightoporia avellanea (Bres.) Pouzar and Wrightoporia lenta (Oveh. & J. Lowe) Pouzar. Polypores are richer in East Asia than in Europe and North America, not only because of destructive galciations and fewer hosts in the latters, but also because of the geography. NE Asia is a link between Europe and North America. Changbaishan Nature Reserve is very rich in polypores, and over 260 species were recorded in the reserve. Some rare species in North America and Europe, for instance, Anomoporia albolutescens, Antrodia crassa, Diplomitoporus flavescens, Inonotopsis subiculosa and Skeletocutis ochroalba etc. were found in Changbaishan Nature Reserve as well, and these species are in fact rare in the earth. Most of the 27 species occurred on fallen trunks or rotten wood in the reserve, but some of them grew on living trees. 18 species occured on substrate of gymnosperms, and 9 species grew on wood of angiosperm.Among the 27 species, 7 species caused a brown rot,and 20 species produced a white rot. The morphology, substrate and ecology of each species were briefly discussed. The most important tool for polypore conservation is the conservation of their habitats, and it is necessary to study the ecology of the rare and threathened species of polypores in the Changbaishan Nature Reserve. Because most of polypores live on the substrate of fallen trunks and rotten wood, it is very important to keep such substrate in the ecosystem.

Protocolos para estabelecimento e caracterização de s��tio específico experimental.

2007

Manejo do solo para a cultura do milho.

2006

Determinação da densidade de solos e de horizontes cascalhentos.

2008

Avaliação da variabilidade espacial do solo em experimentos de eficiência nutricional em milho, conduzidos em área com baixos teores de nutrientes: um estudo de caso.

O presente trabalho trata de um estudo de caso em uma área experimental, descrevendo a abordagem utilizada e as recomendações sugeridas para redução da variabilidade espacial do solo.

Design thinking - a critical analysis.

The latest buzz phrase to enter the world of design research is “Design Thinking”. But is this anything new and does it really have any practical or theoretical relevance to the design world? Many sceptics believe the term has more to do with business strategy and little to do with the complex process of designing products, services and systems. Moreover, many view the term as misleading and a cheap attempt to piggyback the world of business management onto design. This paper seeks to ask is design thinking anything new? Several authors have explicitly or implicitly articulated the term “Design Thinking” before, such as Peter Rowe’s seminal book “Design Thinking” [1] first published in 1987 and Herbert Simon’s “The Sciences of the Artificial” [2] first published in 1969. In Tim Brown’s “Change by Design” [3], design thinking is thought of as a system of three overlapping spaces rather than a sequence of orderly steps namely inspiration – the problem or opportunity that motivates the search for solutions; ideation – the process of generating, developing and testing ideas; and implementation – the path that leads from the design studio, lab and factory to the market. This paper seeks to examine and critically analyse the tenets of this new design thinking manifesto set against three case studies of modern design practice. As such, the paper will compare design thinking theory with the reality of design in practice.

Are There Any Lessons of History?: The English School and the Activity of Being an Historian

Bain, William, 'Are There Any Lessons of History?: The English School and the Activity of Being an Historian', International Politics (2007) 44(5) pp.513-530 RAE2008