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Results 401 - 450 of 2549
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Luo Lian-Wee - - 2012
We demonstrate power insensitive silicon microring resonators without the need for active feedback control. The passive control of the resonance is achieved by utilizing the compensation of two counteracting processes, free carrier dispersion blueshift and thermo-optic redshift. In the fabricated devices, the resonant wavelength shifts less than one resonance linewidth ...
Sun Zhijun - - 2012
The effect of absorption enhancement with metallic nanoparticles on solar cell surfaces is often confused with various optical processes. In this work, the effective absorption rates in the active materials of solar cells are explicitly calculated including all possible factors. The results show that, although the total absorption is highly ...
Huang R - - 2012
Strong white electroluminescence (EL) from SiN-based devices containing Si nanodots with a density of more than 4.6×10<sup>12</sup>/cm<sup>2</sup> was investigated. The white EL illustrates enhanced light emission with increasing applied voltage and can be divided into two components, a dominant peak at ∼710  nm and weak one at ∼550  nm, which are close ...
Duan Qianqian - - 2012
A quantum cutting mechanism for the sublinear near-IR power dependence property in Tb<sup>3+</sup>-Yb<sup>3+</sup> codoped NaYF<sub>4</sub> powders were investigated both experimentally and theoretically. The slopes of Yb<sup>3+</sup> luminescence intensity versus excitation power were fitted to be between 0.5 and 1. We have developed a quantum cutting rate equation model to explain ...
Battiato Alfio - - 2012
We present the results of variable-angle spectroscopic ellipsometry and transmittance measurements to determine the variation of the complex refractive index of ion-implanted single-crystal diamond. An increase is found in both real and imaginary parts at increasing damage densities. The index depth variation is determined in the whole wavelength range between ...
Kozlov Victor V - - 2012
We theoretically investigate the polarization properties of Raman amplifiers based on silicon-on-insulator waveguides, and show that it is possible to realize a waveguide Raman polarizer. The Raman polarizer is a special type of Raman amplifier with the property of producing an amplified and highly repolarized beam when it is fed ...
Su Rongtao - - 2012
We report on active coherent beam combining of two single-frequency nanosecond fiber amplifiers by using stochastic parallel gradient descent algorithm. Each fiber amplifier produces an average power of more than 100 W by using three-stage cascaded amplification. The two laser beams are actively phase-locked with a total average power of 215.8 W, ...
Menzel Christoph - - 2012
Most left-handed metamaterials cannot be described by local effective permittivity or permeability tensors in the visible or near-infrared due to the mesoscopic size of the respective unit cells and the related strong spatial dispersion. We lift this problem and propose a metamaterial exhibiting artificial magnetism that does not suffer from ...
Wei Tao - - 2012
This Letter proposes an optical fiber radio frequency (RF) Mach-Zehnder interferometer (MZI) for sensing applications. An RF modulated laser source is injected into an optical fiber RF-MZI and collected by a photodiode. The interference pattern is observed in the RF domain by sweeping the frequency using a network analyzer. The ...
Courtial Johannes - - 2012
Building on recent work on windows that can be modeled as interfaces between materials with a complex ray-optical refractive-index ratio, we define here objects and images at complex positions. We give an example of an optical component that performs imaging between real and complex object and image positions.
Lin Shyh-Tsong - - 2012
This Letter introduces a polarization phase-shifting Newton interferometer that can be utilized for plane optical surface measurements, a setup constructed to realize the interferometer, and the experimental results from the use of the setup. The results confirm not only the validity but also the feasibility of the interferometer.
Daniault L - - 2012
We experimentally investigate the impact of spectral phase mismatch on the coherent beam combining of two femtosecond fiber chirped-pulse amplifiers. By measuring the differential spectral phase, both linear and nonlinear contributions are identified. An accumulated nonlinear phase as high as 6 rad has been measured, for which a combination efficiency ...
Grassi Guido - - 2012
Current guidelines on antihypertensive treatment emphasize the importance of combination drug treatment for achieving a full blood pressure control. The TALENT Study, involving more than 400 high-risk hypertensive patients, aimed to evaluate the efficacy and safety profile of nifedipine gastrointestinal therapeutic system (GITS) 20 mg/telmisartan 80 mg combination, as compared ...
Fang Hong-Hua - - 2012
Two-beam interference ablation of 1,4-Bis(4-methylstyryl)benzene organic crystal by short laser pulses (10 ns, 355 nm) is presented. The influence of laser fluence, interference period, and pulse number on the morphology have been studied. The morphology is closely associated with the molecular interactions in the crystals, and it could be well ...
Solntsev Alexander S - - 2012
We suggest an application of pump-degenerate four-wave mixing process in tapered waveguides for generation of ultrashort pulses with central frequency tunable over the material transparency range. Our method can produce strongly compressed frequency-converted pulses in presence of group-velocity mismatch and group-velocity dispersion. Additionally, the proposed technique does not require pulse ...
Fülöp J A - - 2012
Recent theoretical calculations predicted an order-of-magnitude increase in the efficiency of terahertz pulse generation by optical rectification in lithium niobate when 500 fs long pump pulses are used, rather than the commonly used ∼100  fs pulses. Even by using longer than optimal pump pulses of 1.3 ps duration, 2.5× higher THz ...
North Thibault - - 2012
We demonstrate the operation of a fiber ring laser using a 19.5 cm segment of As<sub>2</sub>S<sub>3</sub> chalcogenide fiber. The laser is passively mode-locked via nonlinear polarization rotation and provides two different operation regimes of picosecond and noiselike pulses. This ring configuration also enables an accurate measurement of the chromatic dispersion ...
Zaccaria Remo Proietti - - 2012
We report on the possibility of realizing a radial mode on a metallic conical structure by means of a linearly polarized incident wave. This result is utilized for observing surface plasmon polaritons adiabatic compression on a tapered conical nanostructure. The ingredients for radial mode generation are described in terms of ...
Zhu Z H - - 2012
We proposed and fabricated a nanofilm half-wave plate consisting of periodic arrays of orthogonally coupled slit-hole resonator structures in Au film. Experimental results reveal that 95.2% of energy of the incident linearly polarized light is converted to the perpendicular polarization direction after reflection from the nanostructure. The wave plate is ...
Westerveld Wouter J - - 2012
Recently there has been growing interest in sensing by means of optical microring resonators in photonic integrated circuits that are fabricated in silicon-on-insulator (SOI) technology. Taillaert et al. [Proc. SPIE 6619, 661914 (2007)] proposed the use of a silicon-waveguide-based ring resonator as a strain gauge. However, the strong lateral confinement ...
Yeh Yunhae - - 2012
In order to implement a fiber-optic Fabry-Perot tunable filter with a simple configuration, a concave mirror is made at the end of the optical fiber. The concave mirror is fabricated by attaching a thin polycarbonate (PC) film on the fiber end, pressing the PC film with a fiber ball to ...
Wang Qinghua - - 2012
We present the hexagonal digital moiré method for three-directional structural characterization of hexagonal packed nanostructures. A mismatch between a three-way grating and a nanoparticle assembly is shown to produce hexagonal moiré fringes due to the interference between three groups of parallel moiré patterns. The measuring principles of the pitches and ...
Weiss S Benjamin - - 2012
We demonstrate a method for single-detector coherent sensing and automated coalignment of group delays in a coherently combined laser array, enabling robust coherent combining of broadband sources despite initial path mismatches exceeding the laser coherence length. The method is based on Fourier-domain filtering of the coherently combined laser beam to ...
ZieliƄska Joanna A - - 2012
We present a theoretical and experimental study of the ultranarrow bandwidth Faraday anomalous dispersion optical filter operating at the rubidium D<sub>1</sub> line (795 nm). This atomic line gives better performance than other lines for key figures of merit, e.g., simultaneously 71% transmission, 445 MHz bandwidth, and 1.2 GHz equivalent-noise bandwidth.
Luo Zhang - - 2012
In this Letter, we suggest an on-chip integrated isolator based on an add-drop filter with unidirectional Raman-induced gain (or loss). For the steady state, complete one-way propagation for monochromatic signals is realized in the bus waveguide. For transient transmission, the burr is suppressed. And the power consumption is reduced by ...
Dumas Delphine - - 2012
Design of miniature and light cameras requires an optical design breakthrough to achieve good optical performance. Solutions inspired by animals' eyes are the most promising. The curvature of the retina offers several advantages, such as uniform intensity and no field curvature, but this feature is not used. The work presented ...
Sun Quan - - 2012
We report on experimental study of the shrinkage of photopolymerized micro/nanostructures fabricated by femtosecond direct laser writing in organic-inorganic resists. Blueshift of the stop-band positions of fabricated photonic crystals during the drying process, which follows the development and rinsing stages, indicates that the drying process plays an important role in ...
Bahramipanah Mohsen - - 2012
In this numerical study, we present and demonstrate a compact, electrical plasmonic beam-steering device composed of anisotropic material. The splitting angle can be modulated by the external electric or magnetic field. The physical principle of this phenomenon is evaluated from the phase of surface plasmon polaritons and Fabry-Perot (F-P) resonance ...
Huang Min - - 2012
By micro-Raman spectroscopy, we show that the structured surfaces of highly oriented pyrolytic graphite and diamond induced by 800 nm, 125 fs or 532 nm, 30 ps laser pulses are capped by thin amorphous carbon layers. Based on the results, we propose that for multiphoton ablation the thin amorphous layer ...
Hohenau Andreas - - 2012
We launch surface plasmons from one end of a silver nanowire by asymmetric illumination with white light and use plasmon-to-light scattering at the nanowire ends to probe spectroscopically the plasmonic Fabry-Perot wire modes. The spectral positions of the maxima and minima in the scattered intensity from both nanowire ends are ...
Trowbridge Jennifer J - - 2012
Epigenetic mechanisms regulating leukemia stem cells (LSCs) are an attractive target for therapy of blood cancers. Here, we report that conditional knockout of the DNA methyltransferase Dnmt1 blocked development of leukemia, and haploinsufficiency of Dnmt1 was sufficient to delay progression of leukemogenesis and impair LSC self-renewal without altering normal hematopoiesis. ...
Rosonina Emanuel - - 2012
The small ubiquitin-related modifier (SUMO) is a conserved factor that post-translationally regulates proteins involved in many cellular processes, including gene transcription. We previously demonstrated that promoter-bound factors become sumoylated during activation of inducible genes in yeast, but the identity of these factors, and the role of sumoylation in their function, ...
Miles Wayne O - - 2012
E2F transcription factors are important regulators of cell proliferation and are frequently dysregulated in human malignancies. To identify novel regulators of E2F function, we used Drosophila as a model system to screen for mutations that modify phenotypes caused by reduced levels of dE2F1. This screen identified components of the Pumilio ...
Neumann Frank R - - 2012
Chromatin in the interphase nucleus moves in a constrained random walk. Despite extensive study, the molecular causes of such movement and its impact on DNA-based reactions are unclear. Using high-precision live fluorescence microscopy in budding yeast, we quantified the movement of tagged chromosomal loci to which transcriptional activators or nucleosome ...
Chau B Nelson - - 2012
Scarring of the kidney is a major public health concern, directly promoting loss of kidney function. To understand the role of microRNA (miRNA) in the progression of kidney scarring in response to injury, we investigated changes in miRNA expression in two kidney fibrosis models and identified 24 commonly up-regulated miRNAs. ...
Gores Gregory J - - 2012
Bcl-2, Bcl-x(L), Mcl-1, and A1 are the predominant anti-apoptotic members of the Bcl-2 family in somatic cells. Malignant B lymphocytes are critically dependent on Bcl-2 or Bcl-x(L) for survival. In contrast, a new study by Glaser and colleagues in the January 15, 2012, issue of Genes & Development (pp. 120-125) ...
Shimizu-Hirota Ryoko - - 2012
Macrophages play critical roles in events ranging from host defense to obesity and cancer, where they infiltrate affected tissues and orchestrate immune responses in tandem with the remodeling of the extracellular matrix (ECM). Despite the dual roles played by macrophages in inflammation, the functions of macrophage-derived proteinases are typically relegated ...
Strasser Samantha Dale - - 2012
Quantification of intracellular nanoscale macromolecular density distribution is a fundamental aspect to understanding cellular processes. We report a near-field penetrating optical microscopy (NPOM) technique to directly probe the internal nanoscale macromolecular density of biological cells through quantification of intracellular refractive index (RI). NPOM inserts a tapered optical fiber probe to ...
de Leon Jose - - 2012
Pharmacokinetic and pharmacodynamic drug interactions (DIs) can occur between antiepileptics (AEDs) and second-generation antipsychotics (SGAPs). Some AED and SGAP pharmacodynamic mechanisms are poorly understood. AED-SGAP combinations are used for treating comorbid illnesses or increasing efficacy, particularly in bipolar disorder. This article provides a comprehensive review of the interactions between antiepileptics ...
Mannucci Pier Mannuccio - - 2012
Patients with hemophilia now have a life expectancy very close to that of the unaffected male population and, hence, are at risk of developing the classic age-related morbidities, i.e., cardiovascular diseases. The peculiarity of the management of these diseases in hemophilia is that antithrombotic drugs impinge on the already compromised ...
Forestier Nicole - - 2012
More than 180 million people worldwide are infected with the chronic hepatitis C virus (HCV), a major cause of liver cirrhosis, and its life-threatening complications including liver failure, portal hypertension and hepatocellular carcinoma. For patients infected with HCV genotype 1, the chances of a sustained virologic response (SVR) with the ...
Lauzardo Michael M University of Florida, College of Medicine, 1600 SW Archer Road, PO Box 100486, Gainesville, FL 32610-0486, - - 2012
In terms of human suffering, tuberculosis has a huge impact on global society, making it arguably the most important infectious disease in history. Despite the devastating impact on society, the tools to fight tuberculosis are very limited. Current standard therapy has been used for over 40 years and threats, such ...
Fan Weiwei W Center for Molecular and Mitochondrial Medicine and Genetics, University of California at Irvine, 92697, - - 2012
The role of mitochondrial DNA (mtDNA) mutations and mtDNA recombination in cancer cell proliferation and developmental biology remains controversial. While analyzing the mtDNAs of several mouse L cell lines, we discovered that every cell line harbored multiple mtDNA mutants. These included four missense mutations, two frameshift mutations, and one tRNA ...
Bradke Frank F Axonal Growth and Regeneration, German Center for Neurodegenerative Disease, Ludwig-Erhard-Allee 2, 53175 Bonn, - - 2012
The assembly of a new growth cone is a prerequisite for axon regeneration after injury. Creation of a new growth cone involves multiple processes, including calcium signalling, restructuring of the cytoskeleton, transport of materials, local translation of messenger RNAs and the insertion of new membrane and cell surface molecules. In ...
Beck David B DB Howard Hughes Medical Institute, Department of Biochemistry, New York University School of Medicine, New York, 10016, - - 2012
Histone post-translational modifications impact many aspects of chromatin and nuclear function. Histone H4 Lys 20 methylation (H4K20me) has been implicated in regulating diverse processes ranging from the DNA damage response, mitotic condensation, and DNA replication to gene regulation. PR-Set7/Set8/KMT5a is the sole enzyme that catalyzes monomethylation of H4K20 (H4K20me1). It ...
Yao Junjie J Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, - - 2012
Recent developments of optical-resolution photoacoustic microscopy (OR-PAM) have improved its spatial resolution and imaging speed. However, the penetration depth of OR-PAM is still limited to ~1 mm in tissue, owing to the strong tissue scattering. Here, we have developed double-illumination PAM (DI-PAM), which illuminates the sample from both top and ...
Youngstrom Isaac A IA Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, - - 2012
Because many different sensory modalities contribute to spatial learning in rodents, it has been difficult to determine whether spatial navigation can be guided solely by visual cues. Rodents moving within physical environments with visual cues engage a variety of nonvisual sensory systems that cannot be easily inhibited without lesioning brain ...
Wang Yu Y Department of Pathology, University of Washington School of Medicine, Seattle, WA 98104, - - 2012
Phosphorylated α-synuclein (PS-129), a protein implicated in the pathogenesis of Parkinson's disease (PD), was identified by mass spectrometry in human cerebrospinal fluid (CSF). A highly sensitive and specific assay was established and used to measure PS-129 together with total α-synuclein in the CSF of patients with PD, other parkinsonian disorders ...
Deleidi Michela M Harvard Medical School, Boston, MA 02115, - - 2012
Here, we synthesize research behind the emerging hypothesis that inflammation--which can result, for example, from viral infections--can initiate and propagate chronic neuronal dysfunction, an event that precedes the clinical onset of many neurodegenerative diseases. Therapeutic approaches that target immunological pathways in the prodromal phase of diseases might decrease the incidence ...
Rak Janusz - - 2012
VEGF-C and VEGF-D have been implicated in lymphatic metastasis, mainly as inducers of new intra/peritumoral capillary lymphatics. In this issue of Cancer Cell, Karnezis and colleagues challenge this notion and demonstrate that tumor-derived VEGF-D promotes metastasis by causing prostaglandin-dependent dilation of collecting lymphatics outside of the tumor mass.
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