Dewetting of a solid monolayer

We report on the dewetting of a monolayer on a solid substrate, where mass transport occurs via surface diffusion. For a wide range of parameters, a labyrinthine pattern of bilayer islands is formed. An irreversible regime and a thermodynamic regime are identified. In both regimes, the velocity of a dewetting front, the wavelength of the bilayer island pattern, and the rate of nucleation of dewetted zones are obtained. We also point out the existence of a scaling behavior, which is analyzed by means of a geometrical model.Comment: to be published in PhysRevLet

A method of measurement for bone mineral density and newly formed bone quantity using 31P-NMR T2 relaxation time

【緒言】歯槽骨の骨再生治療において、術前に新生骨量や骨質を知ることができれば、適切なインプラント埋入時期の決定に役立つ。また、骨組成や骨塩量の非侵襲的な解析は、系統的骨疾患の診断や研究にも有用である。再生骨に対しては、現在エックス線単純撮影やCTを用いた検査が行われているが、これらの方法では人工骨と新生骨とを見分けることは困難である。また、骨塩量や骨の組成に関しても、非侵襲的で短時間、かつ正確に測定する方法は限られている。これまでの研究で31P-NMRを用いて、骨リン酸カルシウムのT1緩和差を利用した海綿骨部の新生骨量測定法を確立したが、成熟骨と新生骨の割合を得るには二重エネルギーエックス線吸収測定（DXA）法などの骨塩量測定法を併用する欠点があった。また、31P-NMRのみを用いてT1緩和差を利用した骨塩量測定を行う場合には、測定が長時間となり実用性に欠けることが推測された。そこで、本研究ではＴ２緩和時間がT1緩和時間よりも短いことに注目した。T2緩和差を利用することで、31 P-NMRのみで新生骨信号量（新生骨量）、骨塩信号量（骨塩量）を測定する非侵襲的な短時間31 P-NMR二重測定法の確立を目的とした。【方法】31P-NMRによるT2緩和時間の測定条件の探索のため、各種合成リン酸カルシウムのT2磁気緩和動態をCarr Purcell Meiboom Gill （CPMG）法で測定した。Calculation delay、Relaxation delay、積算回数を変数として、それぞれについて最適化を行った。各種合成リン酸カルシウムを骨構成体と考えられているもの、骨リン酸カルシウムの前駆体と考えられているもの、そして人工骨補填剤などの生体硬組織移植材料に含まれる成分の3つに分類し、計11種類を使用した。合成リン酸カルシウムでの基礎検討の結果から、骨塩量、新生骨量の測定条件候補の決定をした。続いて、得られた測定条件候補値を利用し、マウス脛骨を用いた検討を行った。実験には2,4,6,9ヶ月齢の雄BALB/cAJclマウスを各々5匹、合計20匹を用いた。31P-NMR、 CPMG法によるT2信号量の測定を行い、さらに同一サンプルについて、DXA装置による骨塩量の測定を行った。また、テトラサイクリン、カルセインによる骨二重標識（01TC-02-01CL）により組織学的な新生骨量の測定を行い、31P-NMR、 CPMG法によるT2信号量の測定結果との比較を行った。【結果】CPMG法での測定条件のうち、τstepは使用した機器における最小値の182μ秒に設定した。Calculation delayを変数とした場合、特に骨構成体に含まれる材料と生体硬組織移植材料との違いが最も描出されたのが0.348m秒であったため、この値に固定した。次に合成リン酸カルシウムの信号量に及ぼすRelaxation delay と積算回数については、予備実験から候補となる５つの測定条件を決定した。解析の結果、31P-NMRの各条件による信号量とDXAによって測定した骨塩量との間には、相関は認められなかった。一方、31P-NMRの各条件による信号量と海綿骨部の新生骨量（面積）との間には、特にRelaxation delay 10秒、積算回数60回において最も強い相関が認められた。【考察】組織学的に解析した海綿骨部の新生骨の面積と T2緩和時間では、Relaxation delay 10秒、積算60回（測定約10分）を含む複数の条件下で有意な相関を認めたことから、31P-NMRのT2緩和差を利用することで、新生骨量が非侵襲的に測定できる可能性が示唆された。この測定法を将来骨再生医療に用いることができれば、同時に移植された人工骨の影響を排除して、新生骨量のみを測定できる可能性が示された点で画期的と考えられる。また、DXAによって測定した骨塩量とT2緩和時間では相関を認めなかったことから、31P-NMRのT2緩和差のみで骨塩量を測定することは困難と考えられた。その理由として、31P-NMRでは骨リン酸カルシウムのリンの信号を測定していることから、加齢によって骨リン酸カルシウムの組成の内、カルシウムなどの他のミネラル量が変化することが考えられた。今回の結果から、31 P-NMRのT2緩和差を利用した解析は、今後非侵襲的な再生骨量や骨組成の検査に有用である可能性が示された。2016博士（歯学）松本歯科大

Geometry of obstructed equisingular families of projective hypersurfaces

We study geometric properties of certain obstructed equisingular families of projective hypersurfaces with emphasis on smoothness, reducibility, being reduced, and having expected dimension. In the case of minimal obstructness, we give a detailed description of such families corresponding to quasihomogeneous singularities. Next we study the behavior of these properties with respect to stable equivalence of singularities. We show that under certain conditions, stabilization of singularities ensures the existence of a reduced component of expected dimension. For minimally obstructed families the whole family becomes irreducible. As an application we show that if the equisingular family of a projective hypersurface H has a reduced component of expected dimension then the deformation of H induced by the linear system |H| is complete with respect to one-parameter deformations.Comment: 30 pages. v2: more detailed explanations. v3: minor corrections, version to appear in the Journal of Pure and Applied Algebr

The Infrared Imaging Spectrograph (IRIS) for TMT: optical design of IRIS imager with "Co-axis double TMA"

IRIS (InfraRed Imaging Spectrograph) is one of the first-generation instruments for the Thirty Meter Telescope (TMT). IRIS is composed of a combination of near-infrared (0.84--2.4 $\mu$m) diffraction limited imager and integral field spectrograph. To achieve near-diffraction limited resolutions in the near-infrared wavelength region, IRIS uses the advanced adaptive optics system NFIRAOS (Narrow Field Infrared Adaptive Optics System) and integrated on-instrument wavefront sensors (OIWFS). However, IRIS itself has challenging specifications. First, the overall system wavefront error should be less than 40 nm in Y, z, J, and H-band and 42 nm in K-band over a 34.0 $\times$ 34.0 arcsecond field of view. Second, the throughput of the imager components should be more than 42 percent. To achieve the extremely low wavefront error and high throughput, all reflective design has been newly proposed. We have adopted a new design policy called "Co-Axis double-TMA", which cancels the asymmetric aberrations generated by "collimator/TMA" and "camera/TMA" efficiently. The latest imager design meets all specifications, and, in particular, the wavefront error is less than 17.3 nm and throughput is more than 50.8 percent. However, to meet the specification of wavefront error and throughput as built performance, the IRIS imager requires both mirrors with low surface irregularity after high-reflection coating in cryogenic and high-level Assembly Integration and Verification (AIV). To deal with these technical challenges, we have done the tolerance analysis and found that total pass rate is almost 99 percent in the case of gauss distribution and more than 90 percent in the case of parabolic distribution using four compensators. We also have made an AIV plan and feasibility check of the optical elements. In this paper, we will present the details of this optical system.Comment: 18 pages, 14 figures, Proceeding 9908-386 of the SPIE Astronomical Telescopes + Instrumentation 201

Um sistema de teleoftalmologia para triagem de urgências em áreas remotas do Brasil

Purposes: To validate a teleophthalmology mobile system aimed at improving and providing eye urgency screenings in remote and poor area settings in Brazil. The system enables one or more ophthalmologists to remotely examine a patient's condition and submit a decision describing the gravity of the case. If necessary, the patient can be forwarded to a hospital for further consultation. Methods: A cellphone (Nexus One model, with a 5 megapixel camera) was used to collect data and pictures from 100 randomly selected patients at the Ophthalmology Emergency Room located at the General Hospital of the Federal University of São Paulo (UNIFESP). Data was then sent remotely to an online recording system to be reviewed by an ophthalmologist who provided feedback regarding the state of ocular urgency. Results were then compared to the gold standard diagnosis provided at the hospital. Results: The diagnosis of urgency was given by two ophthalmologists: one in the hospital (gold standard) and one remotely. When we compared both diagnoses we obtained results of 81.94% specificity, 92.85% sensitivity, and 85% accuracy, with a negative predictive value of 96.72%. This work also included a processing time analysis, resulting in an average time of 8.6 min per patient for remote consultations. Conclusions: This study is the first that has used only a cellphone for diagnosing the urgency of ocular cases. Based on our results, the system can provide a reliable distinction between urgent and non-urgent situations and can offer a viable alternative for the servicing of underprivileged areas. In screening techniques, the most important outcome is to identify urgent cases with a high level of sensitivity and predictive negative value. Thus, our results demonstrate that this tool is robust and we suggest that a major study aimed to verify its efficiency in resource-poor areas should be initiated.Objetivos: Validar um sistema de teleoftalmologia móvel que tem como objetivo fornecer triagem de urgências oftalmológicas em áreas remotas e desfavorecidas do Brasil. O sistema permite que um ou mais oftalmologistas possam examinar remotamente a condição do paciente e apresentar uma decisão que descreve a gravidade do caso. Se necessário, o paciente será encaminhado ao hospital para consulta. Métodos: Através de um celular e sua câmera (modelo Nexus One com câmera de 5 megapixel), foram coletados dados de 100 pacientes aleatoriamente selecionados no pronto socorro oftalmológico da Universidade Federal de São Paulo (UNIFESP) e enviados remotamente para um sistema online, por meio do qual um oftalmologista analisou-os e enviou um diagnóstico sobre a gravidade dos casos. Os resultados enviados foram comparados com o padrão ouro que foi fornecido pelo médico no hospital. Resultados: O diagnóstico foi fornecido por dois oftalmologistas: um no hospital (padrão outro) e outro remotamente. Comparando os resultados dos diagnósticos, foi obtido 81,94% de especificidade, 92,85% de sensibilidade, acurácia de 85% e um valor preditivo negativo de 96,72%. Também foi testado o desempenho do sistema, resultando num tempo de processamento do atendimento remoto em média de 8,6 minutos por paciente. Conclusões: Esta solução de baixo custo é a primeira da literatura que utiliza apenas o telefone celular para detectar urgências oftalmológicas. Com base nos resultados, o sistema consegue oferecer um atendimento confiável, diferenciando os casos de urgências e não urgências através da plataforma de telemedicina. Como ferramenta de triagem, o mais importante é identificar os casos de urgência (ter alta sensibilidade). Assim, os resultados obtidos demonstram que a ferramenta é robusta e traz uma possibilidade real de conduzir um estudo maior para verificar sua eficiência em áreas mais distantes e desfavorecidas.Universidade Federal do Rio Grande do NorteMassachusetts Institute of TechnologyUniversidade Federal de São Paulo (UNIFESP) Department of OphthalmologyHarvard Medical School (Schepens Eye Research Institute) Department of OphthalmologyUniversidade Federal de São Paulo (UNIFESP) Retina DepartmentUNIFESP, Department of OphthalmologyUNIFESP, Retina DepartmentSciEL

Hydroelectric dams threaten Brazil’s mysterious Pantanal – one of the world’s great wetlands

The Pantanal in central South America may not be as globally famous as the Amazon rainforest, but it has the continent’s highest concentration of wildlife. Now, however, the region’s endangered plants and animals, along with its still undiscovered secrets, may be wiped out in return for cheap hydroelectricity

2013-2014 Master Class - Philip Fowke (Piano)

https://spiral.lynn.edu/conservatory_masterclasses/1043/thumbnail.jp

Scanning electrochemical microscopy as a local probe of oxygen permeability in cartilage

The use of scanning electrochemical microscopy, a high-resolution chemical imaging technique, to probe the distribution and mobility of solutes in articular cartilage is described. In this application, a mobile ultramicroelectrode is positioned close (not, vert, similar1 μm) to the cartilage sample surface, which has been equilibrated in a bathing solution containing the solute of interest. The solute is electrolyzed at a diffusion-limited rate, and the current response measured as the ultramicroelectrode is scanned across the sample surface. The topography of the samples was determined using Ru(CN)64−, a solute to which the cartilage matrix was impermeable. This revealed a number of pit-like depressions corresponding to the distribution of chondrocytes, which were also observed by atomic force and light microscopy. Subsequent imaging of the same area of the cartilage sample for the diffusion-limited reduction of oxygen indicated enhanced, but heterogeneous, permeability of oxygen across the cartilage surface. In particular, areas of high permeability were observed in the cellular and pericellular regions. This is the first time that inhomogeneities in the permeability of cartilage toward simple solutes, such as oxygen, have been observed on a micrometer scale

The Infrared Imaging Spectrograph (IRIS) for TMT: Instrument Overview

We present an overview of the design of IRIS, an infrared (0.84 - 2.4 micron) integral field spectrograph and imaging camera for the Thirty Meter Telescope (TMT). With extremely low wavefront error (<30 nm) and on-board wavefront sensors, IRIS will take advantage of the high angular resolution of the narrow field infrared adaptive optics system (NFIRAOS) to dissect the sky at the diffraction limit of the 30-meter aperture. With a primary spectral resolution of 4000 and spatial sampling starting at 4 milliarcseconds, the instrument will create an unparalleled ability to explore high redshift galaxies, the Galactic center, star forming regions and virtually any astrophysical object. This paper summarizes the entire design and basic capabilities. Among the design innovations is the combination of lenslet and slicer integral field units, new 4Kx4k detectors, extremely precise atmospheric dispersion correction, infrared wavefront sensors, and a very large vacuum cryogenic system.Comment: Proceedings of the SPIE, 9147-76 (2014