By employing SrWO4 as a Raman active medium and a ceramic Nd:YAG laser operating at 1319 and 1338 nm as a pump source, an efficient eye-safe dual-wavelength Raman laser operating at 1501 and 1526 nm has been demonstrated. A maximum total output power as high as 3.36 W is obtained under a pump power of 33.3 W and a pulse repetition frequency (PRF) of 30 kHz. The highest optical-to-optical conversion efficiency of 11.2% is achieved at the pump power of 27.3 W. To our knowledge, 3.36 W is the highest output power of a 1.5 ?m eye-safe Raman laser.
By employing SrWO4 as Raman active media and ceramic Nd:YAG as laser gain media, a diode-pumped actively Q-switched Raman laser is demonstrated. Single or multiple wavelength first-stokes Raman generations at 1238 and 1252 nm are achieved. To our knowledge, this is the first Raman laser demonstration based on fundamental wavelengths around 1.1 ?m. Maximum output powers are 1.02 W at single 1252 nm wavelength, 1.08 W at single 1238 nm wavelength, and 442 mW at multiple wavelengths of 1252 and 1238 nm, corresponding to optical-to-optical conversion efficiencies of 4.78%, 4.95%, and 2.54%, respectively.
KTiOPO? (KTP) crystal is used as the nonlinear medium in a surface-emitted terahertz-wave parametric oscillator for the first time. The oscillating Stokes beam propagates along the x axis of the KTP crystal, the pumping beam propagates with a small incident angle ?(ext) to the x axis, and the polarizations of the pumping beam, the Stokes beam, and the THz wave are along the z axis. When ?(ext) is changed from 1.250° to 6.000°, the THz wave is intermittently tuned from 3.17 to 3.44 THz, from 4.19 to 5.19 THz, and from 5.55 to 6.13 THz. The maximum output of the THz wave is 336 nJ, obtained at 5.72 THz with a pumping energy of 80 mJ. The two frequency gaps, from 3.44 to 4.19 THz and from 5.19 to 5.55 THz, are located in the vicinities of the A? modes of 134 and 178.7??cm?¹, which are strongly infrared absorbing.
A MgO:LiNbO? slab configuration for the surface-emitted terahertz-wave parametric oscillator (TPO) is presented. The pump and the oscillating Stokes beams were totally reflected at the slab surface and propagated zigzaggedly in the slab MgO:LiNbO? crystal. Up to five terahertz beams were emitted perpendicularly to the surface of the crystal. The total output energy of the five THz-wave beams was 3.56 times as large as that obtained from the conventional surface-emitted TPO at the same experimental conditions. The intensity distributions of the THz wave beams were measured, and they were unsymmetrical in the horizontal direction while symmetrical in the vertical direction.
C-type lectins (CTLs) play crucial roles in innate immune responses in invertebrates by recognizing and eliminating microinvaders. In this study, a CTL from pacific white shrimp Litopenaeus vannamei (LvCTL3) was identified. LvCTL3 contains a single C-type lectin-like domain (CTLD), which shows similarities to those of other shrimp CTLs and has a mutated 'EPD' motif in Ca(2+)-binding site 2. LvCTL3 mRNA can be detected in all tested tissues and expression of LvCTL3 in gills was up-regulated after Lipopolysaccharides, poly (I:C), Vibrio parahaemolyticus and white spot syndrome virus (WSSV) challenges, suggesting activation responses of LvCTL3 to bacterial, virus and immune stimulant challenges. The 5'flanking regulatory region of LvCTL3 was cloned and we identified a NF-?B binding motif in the LvCTL3 promoter region. Dual-luciferase reporter assays indicated that over-expression of L. vannamei dorsal can dramatically up regulate the promoter activity of LvCTL3, suggesting that LvCTL3 expression could be regulated through NF-?B signaling pathway. As far as we know, this is the first report on signaling pathway involve in shrimp CTLs expression. The recombinant LvCTL3 protein was expressed in Escherichia coli and purified by Ni-affinity chromatography. The purified LvCTL3 can agglutinate Gram-negative microbe Vibrio alginolyticus and V. parahaemolyticus and Gram-positive bacteria Bacillus subtilis in the presence of calcium ions, but cannot agglutinate Gram-positive bacteria Streptococcus agalactiae. The agglutination activity of LvCTL3 was abolished when Ca(2+) was chelated with EDTA, suggesting the function of LvCTL3 is Ca(2+)-dependent. In vivo challenge experiments showed that the recombinant LvCTL3 protein can significantly reduce the mortalities of V. parahemolyticus and WSSV infection, indicating LvCTL3 might play significant roles in shrimp innate immunity defense against bacterial and viral infection.
The characteristics of a barium tungstate (BaWO(4)) anti-Stokes Raman laser at 968 nm are studied theoretically and experimentally. The BaWO(4) Raman resonator is pumped by a Q-switched Nd:YAG laser at 1064 nm with its axis tilted from the pumping laser axis. The non-collinear phase matching for the generation of the first anti-Stokes wave in the same BaWO(4) crystal is achieved. The output energy, temporal and spectral informations are investigated. At a pumping laser energy of 128 mJ, the anti-Stokes laser energy obtained is 2.2 mJ. The second Stokes radiation at 1324 nm as well as the first and the third Stokes waves at 1180 nm and 1509 nm is also generated at the same time. The maximum total Stokes energy output is 42.5 mJ. In the theory, the anti-Stokes laser intensity expression as a function of the pumping and the first Stokes laser intensities for the extracavity anti-Stokes Raman laser is deduced. The properties of the anti-Stokes Raman laser are simulated theoretically by solving the rate equations of the extracavity Raman laser and using the derived expression. The theoretical results are in good agreement with the experimental results.
A Nd:Gd3Ga5O12 (Nd:GGG) laser operating at a wavelength of 1423.4 nm was demonstrated, which has not yet been reported, and is of great interest for wide application potential. With a pumped power of 18.5 W, a maximum output power of 3.63 W was obtained, corresponding to an optical-to-optical efficiency of 19.6% and a slope efficiency of 26%. These unique characteristics of a Nd:GGG laser at 1423.4 nm thereby open new opportunities for a light source in the field of medicine.
Biocompatibility of nanoparticles has been attracting great interest in the development of nanoscience and nanotechnology. Herein, the aliphatic water-soluble hyperbranched polyester nanoparticles with sulfonic acid functional groups (HBPE-SO3 NPs) were synthesized and characterized. They are amphiphilic polymeric nanoparticles with hydrophobic hyperbranched polyester (HBPE) core and hydrophilic sulfonic acid terminal groups. Based on our observations, we believe there are two forms of HBPE-SO3 NPs in water under different conditions: unimolecular micelles and large multimolecular micelles. The biocompatibility and anticoagulant effect of the HBPE-SO3 NPs were investigated using coagulation tests, hemolysis assay, morphological changes of red blood cells (RBCs), complement and platelet activation detection, and cytotoxicity (MTT). The results confirmed that the sulfonic acid terminal groups can substantially enhance the anticoagulant property of HBPE, and the HBPE-SO3 NPs have the potential to be used in nanomedicine due to their good bioproperties.
Lipoprotein glomerulopathy (LPG) is a rare inherited renal disease characterized by intraglomerular lipoprotein within the lumina of severely dilated glomerular capillaries. The common clinical presentation of LPG includes proteinuria or nephrotic syndrome. Hypertension and anemia were thought to be mild in LPG. Thrombotic microangiopathy (TMA) in LPG has not been previously reported. In this report, we present a patient with LPG that developed TMA. To the best of our knowledge, this is the first report of TMA in LPG.
Acknowledging the benefits of hyperbranched polymers and their nanoparticles, herein we report the design and synthesis of sulfonic acid group functionalized hydroxyl-terminated hyperbranched polyester (H30-SO3H) nanoparticles and their biomedical application. The H30-SO3H nanoparticles were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance spectroscopy ((1)H NMR). The good hemocompatibility of H30-SO3H nanoparticles was also investigated by coagulation tests, complement activation and platelet activation. The novel glucose biosensor was fabricated by immobilizing the positively charged Au nanoparticles, H30-SO3H nanoparticles and glucose oxidase (GOx) onto the surface of glassy carbon electrode (GCE). It can be applied in whole blood directly, which was based on the good hemocompatibility and antibiofouling property of H30-SO3H nanoparticles. The biosensor had good electrocatalytic activity toward glucose with a wide linear range (0.2-20 mM), a low detection limit 1.2×10(-5) M in whole blood and good anti-interference property. The development of materials science will offer a novel platform for application to substance detection in whole blood.
The Pacific white shrimp, Litopenaeus vannamei, is a worldwide cultured crustacean species with important commercial value. Over the last two decades, Taura syndrome virus (TSV) has seriously threatened the shrimp aquaculture industry in the Western Hemisphere. To better understand the interaction between shrimp immune and TSV, we performed a transcriptome analysis in the hepatopancreas of L. vannamei challenged with TSV, using the 454 pyrosequencing (Roche) technology.
Pacific white shrimp (Litopenaeus vannamei) is the most extensively farmed crustacean species in the world. White spot syndrome virus (WSSV) is one of the major pathogens in the cultured shrimp. However, the molecular mechanisms of the host-virus interaction remain largely unknown. In this study, the impact of WSSV infection on host gene expression in the hepatopancreas of L. vannamei was investigated through the use of 454 pyrosequencing-based RNA-Seq of cDNA libraries developed from WSSV-challenged shrimp or normal controls. By comparing the two cDNA libraries, we show that 767 host genes are significantly up-regulated and 729 genes are significantly down-regulated by WSSV infection. KEGG analysis of the differentially expressed genes indicated that the distribution of gene pathways between the up- and down-regulated genes is quite different. Among the differentially expressed genes, several are found to be involved in various processes of animal defense against pathogens such as apoptosis, mitogen-activated protein kinase (MAPK) signaling, toll-like receptor (TLR) signaling, Wnt signaling and antigen processing and presentation pathways. The present study provides valuable information on differential expression of L. vannamei genes following WSSV infection and improves our current understanding of this host-virus interaction. In addition, the large number of transcripts obtained in this study provides a strong basis for future genomic research on shrimp.
A diode-side-pumped actively Q-switched intracavity frequency-doubled Nd:YAG/BaWO(4)/KTP Raman laser is studied experimentally and theoretically. Rate equations are used to analyze the Q-switched yellow laser by considering the transversal distributions of the intracavity photon density and the inversion population density. An 8.3 W 590 nm laser is obtained with a 125.8 W 808 nm pump power and a 15 kHz pulse repetition frequency. The corresponding optical conversion efficiency from diode laser to yellow laser is 6.57%, much higher than that of the former reported side-pumped yellow laser. The output powers with respect to the incident pump power are in agreement with the theoretical results on the whole.
Models of diesel engine emissions such as oxides of nitrogen (NO(x)) are valuable when they can predict instantaneous values because they can be incorporated into whole vehicle models, support inventory predictions, and assist in developing superior engine and aftertreatment control strategies. Recent model-year diesel engines using multiple injection strategies, exhaust gas recirculation, and variable geometry turbocharging may have more transient sensitivity and demand more sophisticated modeling than for legacy engines. Emissions data from 1992, 1999, and 2004 model-year U.S. truck engines were modeled separately using a linear approach (with transient terms) and multivariate adaptive regression splines (MARS), an adaptive piece-wise regression approach that has limited prior use for emissions prediction. Six input variables based on torque, speed, power, and their derivatives were used for MARS. Emissions time delay was considered for both models. Manifold air temperature (MAT) and manifold air pressure (MAP) were further used in NO(x) modeling to build a plug-in model. The predictive performance for instantaneous NO(x) on part of the certification transient test procedure (Federal Test Procedure [FTP]) of the 2004 engine MARS was lower (R2 = 0.949) than the performance for the 1992 (R2 = 0.981) and 1999 (R2 = 0.988) engines. Linear regression performed similarly for the 1992 and 1999 engines but performed poorly (R2 = 0.896) for the 2004 engine. The MARS performance varied substantially when data from different cycles were used. Overall, the MAP and MAT plug-in model trained by MARS was the best, but the performance differences between LR and MARS were not substantial.
An efficient intracavity frequency-doubled Raman laser was obtained by using an SrWO(4) Raman medium, an Nd:YAG ceramic gain medium, and a KTP frequency-doubling medium. Three laser cavities, including a two-mirror cavity, a three-mirror coupled cavity, and a folded cavity, were investigated. With the coupled cavity, a 2.93 W, 590 nm laser was obtained at an incident pump power of 16.2 W and a pulse repetition frequency of 20 kHz; the corresponding conversion efficiency was 18.1%. The highest conversion efficiency of 19.2% was obtained at an incident pump power of 14.1 W and a pulse repetition frequency of 15 kHz. The obtained maximum output power and conversion efficiency were much higher than the results previously obtained with intracavity frequency-doubled solid-state Raman lasers.
The ability of practical recognition systems to recognize a large number of objects is constrained by a variety of factors that include choice of a feature extraction technique, quality of images, complexity and variability of underlying objects and of collected data. Given a feature extraction technique generating templates of objects from data and a resolution of the original images, the remaining factors can be attributed to distortions due to a recognition channel. We define the recognition channel as the environment that transforms reference templates of objects in a database into templates submitted for recognition. If templates in an object database are generated to be statistically independent and the noise in a query template is statistically independent of templates in the database, then the abilities of the recognition channel to recognize a large number of object classes can be characterized by a number called recognition capacity. In this paper, we evaluate the empirical recognition capacity of PCA-based object recognition systems. The encoded data (templates) and the additive noise in query templates are modeled to be Gaussian distributed with zero mean and estimated variances. We analyze both the case of a single encoded image and the case of encoded correlated multiple images. For this case, we propose a model that is orientation and elevation angle (pose) dependent. The fit of proposed models is judged using statistical goodness of fit tests. We define recognition rate as the ratio R=log(M)/n, where M is the number of objects to recognize and n is the length of PCA templates. The empirical capacity of PCA-based recognition systems is numerically evaluated. The empirical random coding exponent is also numerically evaluated and plotted as a function of the recognition rate. With these results, given a value of the recognition capacity and the length of templates (assume large), we can predict the number of distinct object classes that can be stored in an object library and be identified with probability of error close to zero.
A diode-pumped, actively Q-switched second-Stokes dual-wavelength laser employing ceramic Nd:YAG as the gain medium and BaWO(4) as the Raman medium is demonstrated. The dual-wavelength Raman laser emission at 1321 and 1325 nm is based on the dual-wavelength fundamental laser emission at 1061 and 1064 nm. With a pump power of 18.4 W and pulse repetition frequency of 15 kHz, a maximum dual-wavelength output power of 1.67 W was obtained, comprising a 0.75 W, 1321 nm laser component and a 0.92 W, 1325 nm laser component. The corresponding dual-wavelength second-Stokes pulse width was 2.9 ns.
1st-Stokes and 2nd-Stokes dual-wavelength operation within a diode-side-pumped Q-switched Nd:YAG/BaWO(4) intracavity Raman laser was realized. Using an output coupler of transmission of 3.9% at 1180 nm and transmission of 60.08% at 1325 nm, the maximum output power of 8.30 W and 2.84 W at a pulse repetition rate of 15 kHz for the 1st Stokes and the 2nd Stokes laser were obtained, respectively. The corresponding optical conversion efficiency from diode laser to the 1st Stokes and 2nd Stokes laser are 5.0% and 1.4%, respectively. With the pump power of 209 W and a pulse repetition rate of 15 kHz, the 1st Stokes and the 2nd Stokes pulse widths were 20.5 ns and 5.8 ns, respectively. The stable simultaneous Q-switching and mode locking of the 2nd Stokes laser without mode locking component was obtained at the pump power of about 29~82 W. The estimated mode-locked pulse width was approximately 31 ps at the pump power of 50 W and a pulse repetition rate of 15 kHz.
A diode-pumped, actively Q-switched dual-wavelength laser employing Nd:YVO(4) self-Raman emission at 1524 nm and undoped GdVO(4) Raman emission at 1522 nm is demonstrated. With a pump power of 21.5 W and pulse repetition frequency of 20 kHz, a maximum dual-wavelength output power of 1.62 W was obtained, comprising a 0.54 W, 1522 nm Raman component and 1.08 W, 1524 nm self-Raman component. The corresponding dual-wavelength Raman pulse width was 5.6 ns. The experimental results indicate that this laser, with quite small wavelength separation, was effective by virtue of simultaneous self-Raman and Raman shifts.
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