We present some photonic-crystal-fiber structures, made up soft glass, that generate ultrawide (over an octave) and very smooth supercontinuum spectrum when illuminated with femtosecond pulsed light. ...The design of the fiber geometry in order to reach a nearly ultraflattened normal dispersion behavior is crucial to accomplish the above goals. We recognize that the above supercontinuum sources show high stability and no significant changes are detected even for fairly large fluctuations of the peak power of the incident pulses.
We study the group-velocity-dispersion properties of a novel type of Bragg fibers. These new structures are cylindrically symmetric microstructured fibers having a high-index core (silica in our ...case), like in conventional photonic crystal fibers, surrounded by a multilayered cladding, which is formed by a set of alternating layers of silica and a lower refractive-index dielectric. The combination of the unusual geometric dispersion behavior shown by the multilayered structure and the material dispersion corresponding to the silica core allows us to design nearly constant chromatic dispersion profiles. In this work we focus our attention on flattened dispersion fibers in the 0.8 microm wavelength window and even on ultraflattened dispersion structures about the 1.55 microm point. We include configurations owning positive, negative, and nearly-zero dispersion in both wavelength ranges.
Ancillary services for distributed generation (DG) systems become a challenging issue to smartly integrate renewable-energy sources into the grid. Voltage control is one of these ancillary services ...which can ride through and support the voltage under grid faults. Grid codes from the transmission system operators describe the behavior of the energy source, regulating voltage limits and reactive power injection to remain connected and support the grid under fault. On the basis that different kinds of voltage sags require different voltage support strategies, a flexible control scheme for three-phase grid-connected inverters is proposed. In three-phase balanced voltage sags, the inverter should inject reactive power in order to raise the voltage in all phases. In one- or two-phase faults, the main concern of the DG inverter is to equalize voltages by reducing the negative symmetric sequence and clear the phase jump. Due to system limitations, a balance between these two extreme policies is mandatory. Thus, over- and undervoltage can be avoided, and the proposed control scheme prevents disconnection while achieving the desired voltage support service. The main contribution of this work is the introduction of a control algorithm for reference current generation that provides flexible voltage support under grid faults. Two different voltage sags have been experimentally tested to illustrate the behavior of the proposed voltage support control scheme.
An early drug discovery approach focusing on gene families can benefit fromstrategies that exploit common signalingmechanisms to more effectively identify and characterize novel chemical lead ...structures. Multiplexing, defined as the screening of multiple targets within the same experiment, is an example of this strategy. Here, the authors describe a technique that allows multiplexing of a common assay type used to study G-protein–coupled receptors: changes in intracellular Ca2+ levels as measured by Molecular Device's fluorometric imaging plate reader (FLIPR®). The multiplexed FLIPR assays showed the expected pharmacological properties of single assays, with good reproducibility and Z' factors. The authors used them to screen large compound libraries in 2 multiplexed assay designs. The 1st used a single-cell line expressing 2 different receptors and the 2nd amixture of 2 cell lines of the same type each expressing distinct receptors. Screening using thesemultiplexed assays produced significant savings in reagents, time, and human resources and allowed the authors to quickly identify specific and selective hits. (Journal of Biomolecular Screening 2005:780-787)
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
BackgroundTumor orchestrated metabolic changes in the microenvironment limit generation of anti-tumor immune responses. Availability of arginine, a semi-essential amino acid, is critical for ...lymphocyte proliferation and function. Levels of arginine are regulated by the enzymes arginase 1,2 and nitric oxide synthase (NOS). However, the role of arginase activity in lung tumor maintenance has not been investigated in clinically relevant orthotopic tumor models.MethodsRNA sequencing (RNA-seq) of sorted cell populations from mouse lung adenocarcinomas derived from immunocompetent genetically engineered mouse models (GEMM)s was performed. To complement mouse studies, a patient tissue microarray consisting of 150 lung adenocarcinomas, 103 squamous tumors, and 54 matched normal tissue were stained for arginase, CD3, and CD66b by multiplex immunohistochemistry. Efficacy of a novel arginase inhibitor compound 9 in reversing arginase mediated T cell suppression was determined in splenocyte ex vivo assays. Additionally, the anti-tumor activity of this compound was determined in vitro and in an autochthonous immunocompetent KrasG12D GEMM of lung adenocarcinoma model.ResultsAnalysis of RNA-seq of sorted myeloid cells suggested that arginase expression is elevated in myeloid cells in the tumor as compared to the normal lung tissue. Accordingly, in the patient samples arginase 1 expression was mainly localized in the granulocytic myeloid cells and significantly elevated in both lung adenocarcinoma and squamous tumors as compared to the controls. Our ex vivo analysis demonstrated that myeloid derived suppressor cell (MDSC)s cause T cell suppression by arginine depletion, and suppression of arginase activity by a novel ARG1/2 inhibitor, compound 9, led to restoration of T cell function by increasing arginine. Treatment of KrasG12D GEMM of lung cancer model with compound 9 led to a significant tumor regression associated with increased T cell numbers and function, while it had no activity across several murine and human non-small cell (NSCLC) lung cancer lines in vitro.ConclusionsWe show that arginase expression is elevated in mouse and patient lung tumors. In a KRASG12D GEMM arginase inhibition diminished growth of established tumors. Our data suggest arginase as an immunomodulatory target that should further be investigated in lung tumors with high arginase activity.
We present a new modelization technique of the human eye based on the calculation of light distributions inside the eye. The method is applied to the study of the crystalline model proposed by ...Kasprzak and Popiolek. We obtain corneal surface data and axial lengths for two groups of real eyes. With these data, we construct a diffractive model of a human eye, which permits calculation of propagated light distributions at any distance inside the eye. The real crystalline lens is substituted by Kasprzak's model, thus obtaining a realistic model eye. From calculated patterns, we obtain the Strehl ratio and the modulation transfer functions of 44 eyes, divided in two groups according to the age. We compare our results with those in the bibliography. Finally, we check the performance of the method through individual comparison of the calculated image positions with respect to the retina with the refractive data for the each subject. We have observed good agreement between our method and results from other authors. We also find reasonable correlation between calculated refraction and subjective exams.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The Saccharomyces cerevisiae Golgi lumenal guanosine diphosphatase is hypothesized to generate GMP which in turn allows entry of GDP-mannose into the lumen to serve as substrate for mannosylation of ...proteins and lipids. We have recently shown in studies in vivo that this GDPase is required for protein and sphingolipid mannosylation in the Golgi lumen of S. cerevisiae. We have now isolated Golgi-vesicles from wild type and gda1 null mutants (GDPase defective) and have found that the initial rate of GDP-mannose entry into mutant vesicles was 5-fold lower than into those of wild type. Because the concentration of GDP within vesicles is insufficient to inhibit Golgi lumenal mannosyltransferases and the null mutant vesicles are impaired in synthesis of Golgi mannoproteins, the above results demonstrate that the reduced availability of GDP-mannose in the null mutants is the cause for altered Golgi mannosylation of macromolecules
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
PDF
