Photonics Integrations Enabling High-end Applications Of Inp In Optical Data Transmissions

We present here results from a uniquely designed InP modulator chip combined with advanced packaging concepts, which enables high-end applications in optical data communications. An electroabsorption (EA) modulator, with a strained InGaAsP or InGaAlAs multiple quantum well structure, is monolithically integrated with a semiconductor optical amplifier. This design offers broad wavelength tunability while maintaining high extinction ratio, high optical output power, and high dispersion tolerance. The amplified EA modulator chip is co-packaged with a distributed feed back (DFB) laser ensuring separate optimization of the laser and modulator sections. The optical isolator, placed between the laser and modulator, completely eliminates adiabatic chirp. This Telcordia-qualified laser integrated modulator platform enables superior performance previously not thought possible for InP absorption based modulators. 11 dB of dynamic extinction ratio, 5dBm of modulated output power, and ±1200ps/nm or +1600ps/nm dispersion tolerance can be simultaneously achieved in un-amplified 10Gb/s data transmission. Full C-band tunability using a single device is also demonstrated with the LIM module. Extensive simulations and transmission system evaluations shows that with the controllable chirp, the cost-effective LIM performs as well as a Mach-Zehnder modulator in dispersion managed and amplified long-haul WDM systems. Lastly, the first uncooled 10Gb/s long-reach operation at 1550nm was demonstrated with LIM packages. Using a simple control algorithm, a constant modulated output power of IdBm with less than IdB dispersion penalty over 1600ps/nm single mode fiber is achieved in an 80 degrees environmental temperature range without any module temperature control. Utilizing the Al-based material system, also allows a reduced variation of the extinction ratio.6013Kaminow, I.P., Koch, T.L., (1997) Optical Fiber Telecommunications IIIA, , San Diego CA: Academic PressChoi, W., Bond, A.E., Kim, J., Zhang, J., Jambunathan, R., Foulk, H., O'Brien, S., Cao, H., Low insertion loss and low dispersion penalty InGaAsP quantum well high speed electroabsorption modulators (2002) IEEE Journal of Lightwave Technologies, 20, pp. 2052-2056Choi, W., Frateschi, N., Zhang, J., Gebretsadik, H., Jambunathan, R., Bond, A.E., Van Norman, J., Wanamaker, C., Full C-band tunable high fiber output power electroabsorption modulator integrated with semiconductor optical amplifier (2003) Electronics Letters, 39, p. 1271. , 2003Zhang, L., Cao, X.D., Long haul transmission using electro-absorption modulators (2002) Technical Proceeding of NFOEC'2002, p. 1204. , paper P447www.vpiphotonics.comMikhailov, V., Killey, R.I., Prat, J., Bayvel, P., Limitation to WDM transmission distance due to cross-phase modulation induced spectral broadening in dispersion compensated standard fiber systems (1999) IEEE Photon. Technol. Lett., 11, pp. 994-996Zhang, J., Frateschi, N., Choi, W., Gebretsadik, H., Jambunathan, R., Bond, A.E., A laser integrated modulator module for uncooled, 10Gbit/s 1550 nm long reach data transmission (2003) Electronics Letters, 39, pp. 1841-1842Frateschi, N.C., Zhang, J., Choi, W.J., Gebretsadik, H., Jambunathan, R., Bond, A.E., High performance uncooled C-band, 10 Gb/s InGaAlAs MQW electro-absorption modulator integrated to Semiconductor Amplifier in Laser integrated modules (2004) Electronics Letters, 40, pp. 140-141. , JanFrateschi, N.C., Zhang, J., Jambunathan, R., Choi, W.J., Ebert, C., Bond, A.E., Long reach uncooled performance of 10 Gb/s Laser integrated modules with InGaAlAs/InP and InGaAsP/InP MQW electroabsorption modulators monolithically integrated with Semiconductor Amplifiers IEEE Photon. Technol. Lett., 17, pp. 1378-138

Sorghum grain hardness and its relationship to mold susceptibility and mold resistance

Sorghum [Sorghum bicolor (L.) Moench] cultivars exhibiting contrasting reactions to the gram mold complex were grown at Patancheru, India, in one postrainy (1988-1989) and two consecutive rainy seasons (1989 and 1990). Sorghum grain hardness was measured by four methods: grinding time required to obtain a fixed volume of flour from grains in a Stenvert hardness tester, force required to break the grains using Kiya and Instron food testers, and density grading in sodium nitrate solution measured as percentage of floating grains. Ergosterol concentration was determined in grains to assess the extent of mold damage. The Stenvert method was convenient and rapid and was significantly correlated with the other three methods but negatively and significantly correlated with the ergosterol concentration. Grains grown in the postrainy season exhibited higher hardness than those grown in the rainy seasons. Mold-resistant cultivars exhibited significantly greater hardness than mold-susceptible cultivars. Ergosterol concentration indicating the extent of mold attack was negatively and significantly( P < 0.01) correlated with Stenvert hardness values in mold-resistant phenotypically white sorghum grains (without testa) in both the rainy seasons

Mashing with unmalted sorghum using a novel low temperature enzyme system: impacts of sorghum grain composition and microstructure

Brewing lager beers from unmalted sorghum traditionally requires the use of high temperature mashing and exogenous enzymes to ensure adequate starch conversion. Here, a novel low-temperature mashing system is compared to a more traditional mash in terms of the wort quality produced (laboratory scale) from five unmalted sorghums (2 brewing and 3 non-brewing varieties). The low temperature mash generated worts of comparable quality to those resulting from a traditional energy intensive mash protocol. Furthermore, its performance was less dependent on sorghum raw material quality, such that it may facilitate the use of what were previously considered non-brewing varieties. Whilst brewing sorghums were of lower protein content, protein per se did not correlate with mashing performance. Rather, it was the way in which protein was structured (particularly the strength of protein starch interactions) which most influenced brewing performance. RVA profile was the easiest way of identifying this characteristic as potentially problematic

Nanofluid impingement jet heat transfer

Experimental investigation to study the heat transfer between a vertical round alumina-water nanofluid jet and a horizontal circular round surface is carried out. Different jet flow rates, jet nozzle diameters, various circular disk diameters and three nanoparticles concentrations (0, 6.6 and 10%, respectively) are used. The experimental results indicate that using nanofluid as a heat transfer carrier can enhance the heat transfer process. For the same Reynolds number, the experimental data show an increase in the Nusselt numbers as the nanoparticle concentration increases. Size of heating disk diameters shows reverse effect on heat transfer. It is also found that presenting the data in terms of Reynolds number at impingement jet diameter can take into account on both effects of jet heights and nozzle diameter. Presenting the data in terms of Peclet numbers, at fixed impingement nozzle diameter, makes the data less sensitive to the percentage change of the nanoparticle concentrations. Finally, general heat transfer correlation is obtained verses Peclet numbers using nanoparticle concentrations and the nozzle diameter ratio as parameters

Wheat TaRab7 GTPase Is Part of the Signaling Pathway in Responses to Stripe Rust and Abiotic Stimuli

Small GTP-binding proteins function as regulators of specific intercellular fundamental biological processes. In this study, a small GTP-binding protein Rab7 gene, designated as TaRab7, was identified and characterized from a cDNA library of wheat leaves infected with Puccinia striiformis f. sp. tritici (Pst) the wheat stripe rust pathogen. The gene was predicted to encode a protein of 206 amino acids, with a molecular mass of 23.13 KDa and an isoeletric point (pI) of 5.13. Further analysis revealed the presence of a conserved signature that is characteristic of Rab7, and phylogenetic analysis demonstrated that TaRab7 has the highest similarity to a small GTP binding protein gene (BdRab7-like) from Brachypodium distachyon. Quantitative real-time PCR assays revealed that the expression of TaRab7 was higher in the early stage of the incompatible interactions between wheat and Pst than in the compatible interaction, and the transcription level of TaRab7 was also highly induced by environmental stress stimuli. Furthermore, knocking down TaRab7 expression by virus induced gene silencing enhanced the susceptibility of wheat cv. Suwon 11 to an avirulent race CYR23. These results imply that TaRab7 plays an important role in the early stage of wheat-stripe rust fungus interaction and in stress tolerance

FSP27 Promotes Lipid Droplet Clustering and Then Fusion to Regulate Triglyceride Accumulation

Fat Specific Protein 27 (FSP27), a lipid droplet (LD) associated protein in adipocytes, regulates triglyceride (TG) storage. In the present study we demonstrate that FSP27 plays a key role in LD morphology to accumulate TGs. We show here that FSP27 promotes clustering of the LDs which is followed by their fusion into fewer and enlarged droplets. To map the domains of FSP27 responsible for these events, we generated GFP-fusion constructs of deletion mutants of FSP27. Microscopic analysis revealed that amino acids 173–220 of FSP27 are necessary and sufficient for both the targeting of FSP27 to LDs and the initial clustering of the droplets. Amino acids 120–140 are essential but not sufficient for LD enlargement, whereas amino acids 120–210 are necessary and sufficient for both clustering and fusion of LDs to form enlarged droplets. In addition, we found that FSP27-mediated enlargement of LDs, but not their clustering, is associated with triglyceride accumulation. These results suggest a model in which FSP27 facilitates LD clustering and then promotes their fusion to form enlarged droplets in two discrete, sequential steps, and a subsequent triglyceride accumulation

Substrate Specifity Profiling of the Aspergillus fumigatus Proteolytic Secretome Reveals Consensus Motifs with Predominance of Ile/Leu and Phe/Tyr

The filamentous fungus Aspergillus fumigatus (AF) can cause devastating infections in immunocompromised individuals. Early diagnosis improves patient outcomes but remains challenging because of the limitations of current methods. To augment the clinician's toolkit for rapid diagnosis of AF infections, we are investigating AF secreted proteases as novel diagnostic targets. The AF genome encodes up to 100 secreted proteases, but fewer than 15 of these enzymes have been characterized thus far. Given the large number of proteases in the genome, studies focused on individual enzymes may overlook potential diagnostic biomarkers.As an alternative, we employed a combinatorial library of internally quenched fluorogenic probes (IQFPs) to profile the global proteolytic secretome of an AF clinical isolate in vitro. Comparative protease activity profiling revealed 212 substrate sequences that were cleaved by AF secreted proteases but not by normal human serum. A central finding was that isoleucine, leucine, phenylalanine, and tyrosine predominated at each of the three variable positions of the library (44.1%, 59.1%, and 57.0%, respectively) among substrate sequences cleaved by AF secreted proteases. In contrast, fewer than 10% of the residues at each position of cleaved sequences were cationic or anionic. Consensus substrate motifs were cleaved by thermostable serine proteases that retained activity up to 50°C. Precise proteolytic cleavage sites were reliably determined by a simple, rapid mass spectrometry-based method, revealing predominantly non-prime side specificity. A comparison of the secreted protease activities of three AF clinical isolates revealed consistent protease substrate specificity fingerprints. However, secreted proteases of A. flavus, A. nidulans, and A. terreus strains exhibited striking differences in their proteolytic signatures.This report provides proof-of-principle for the use of protease substrate specificity profiling to define the proteolytic secretome of Aspergillus fumigatus. Expansion of this technique to protease secretion during infection could lead to development of novel approaches to fungal diagnosis