39 research outputs found
3D Flapping Trajectory of a Micro-Air-Vehicle and its Application to Unsteady Flow Simulation
[[abstract]]A three-dimensional (3D) trajectory detection framework using two high-speed cameras for the flapping flexible wing of a micro-air-vehicle (MAV) is presented. This MAV, which is called the âGolden Snitchâ, has a successful flight record of 8 minutes. We embed the flexible wingskin with a nine light emitting diode (LED) array as the light enhancing marker and capsulate it with parylene (poly-para-xylylene) as the protection layer. We confirm an oblique figure of eight trajectory of this MAVâs wing with time-varying coordinate data. The corresponding aerofoil of the main wingsâ profiles was subjected to the time-varying coordinate data, yielding a resolution of a 1/70 wing beating cycle of 15Hz flapping. The trajectory information is first demonstrated as the moving boundaries of an unsteady flow simulation around a flapping flexible wing.[[notice]]èŁæŁćźçą[[journaltype]]ćć€[[incitationindex]]SCI[[ispeerreviewed]]Y[[booktype]]é»ćç[[booktype]]çŽæŹ[[countrycodes]]HR
Radiation inactivation analysis of thylakoid protein kinase systems in light and in darkness
Chloroplast thylakoid contains several membrane-bound protein kinases that phosphorylate thylakoid polypeptides for the regulation of photosynthesis. Thylakoid protein phosphorylation is activated when the plastoquinone pool is reduced either by light-dependent electron flow through photosystem 2 (PS2) or by adding exogenous reductants such as durohydroquinone in the dark. The major phosphorylated proteins on thylakoid are components of light-harvesting complex 2 (LHC2) and a PS2 associated 9 kDa phosphoprotein. Radiation inactivation technique was employed to determine the functional masses of various kinases for protein phosphorylation in thylakoids. Under the photosynthetically active radiation (PAR), the apparent functional masses of thylakoid protein kinase systems (TPKXs) for catalyzing phosphorylation of LHC2 27 and 25 kDa polypeptides were 540 +/- 50 and 454 +/- 35 kDa as well as it was 448 +/- 23 kDa for PS2 9 kDa protein phosphorylation. Furthermore, the functional sizes of dark-regulated TPKXs for 25 and 9 kDa proteins were 318 +/- 25 and 160 +/- 8 kDa. The 9 kDa protein phosphorylation was independent of LHC2 polypeptides phosphorylation with regard to its TPKX functional mass. Target size analysis of protein phosphorylation mentioned above indicates that thylakoid contains a group of distinct protein kinase systems. A working model is accordingly proposed to interpret the interaction between these protein kinase systems
Synthesis and Pharmacological Evaluation of Triazolopyrimidinone Derivatives as Noncompetitive, Intracellular Antagonists for CC Chemokine Receptors 2 and 5
CC chemokine receptors 2 (CCR2) and 5 (CCR5) are involved in many inflammatory diseases; however, most CCR2 and CCR5 clinical candidates have been unsuccessful. (Pre)clinical evidence suggests that dual CCR2/CCR5 inhibition might be more effective in the treatment of such multifactorial diseases. In this regard, the highly conserved intracellular binding site in chemokine receptors provides a new avenue for the design of multitarget ligands. In this study, we synthesized and evaluated the biological activity of a series of triazolopyrimidinone derivatives in CCR2 and CCR5. Radioligand binding assays first showed that they bind to the intracellular site of CCR2, and in combination with functional assays on CCR5, we explored structureâaffinity/activity relationships in both receptors. Although most compounds were CCR2-selective, 39 and 43 inhibited ÎČ-arrestin recruitment in CCR5 with high potency. Moreover, these compounds displayed an insurmountable mechanism of inhibition in both receptors, which holds promise for improved efficacy in inflammatory diseases.Medicinal Chemistr
Multiwavelength observations of 3C 454.3. III. Eighteen months of agile monitoring of the "crazy diamond"
We report on 18 months of multiwavelength observations of the blazar 3C 454.3 (Crazy Diamond) carried out in the period 2007 July-2009 January. In particular, we show the results of the AGILE campaigns which took place on 2008 May-June, 2008 July-August, and 2008 October-2009 January. During the 2008 May-2009 January period, the source average flux was highly variable, with a clear fading trend toward the end of the period, from an average Îł-ray flux F E>100 MeV âł 200 Ă 10-8photonscm -2s-1 in 2008 May-June, to F E>100 MeV 80 Ă 10-8photonscm-2s-1 in 2008 October-2009 January. The average Îł-ray spectrum between 100 MeV and 1 GeV can be fit by a simple power law, showing a moderate softening (from ÎGRID ⌠2.0 to ÎGRID ⌠2.2) toward the end of the observing campaign. Only 3Ï upper limits can be derived in the 20-60 keV energy band with Super-AGILE, because the source was considerably off-axis during the whole time period. In 2007 July-August and 2008 May-June, 3C 454.3 was monitored by Rossi X-ray Timing Explorer (RXTE). The RXTE/Proportional Counter Array (PCA) light curve in the 3-20 keV energy band shows variability correlated with the Îł-ray one. The RXTE/PCA average flux during the two time periods is F 3-20 keV = 8.4 Ă 10-11ergcm-2s -1, and F 3-20 keV = 4.5 Ă 10 -11ergcm-2s-1, respectively, while the spectrum (a power law with photon index ÎPCA = 1.65 0.02) does not show any significant variability. Consistent results are obtained with the analysis of the RXTE/High-Energy X-Ray Timing Experiment quasi-simultaneous data. We also carried out simultaneous Swift observations during all AGILE campaigns. Swift/XRT detected 3C 454.3 with an observed flux in the 2-10 keV energy band in the range (0.9-7.5) Ă 10-11ergcm-2s-1 and a photon index in the range ÎXRT = 1.33-2.04. In the 15-150 keV energy band, when detected, the source has an average flux of about 5mCrab. GASP-WEBT monitored 3C 454.3 during the whole 2007-2008 period in the radio, millimeter, near-IR, and optical bands. The observations show an extremely variable behavior at all frequencies, with flux peaks almost simultaneous with those at higher energies. A correlation analysis between the optical and the Îł-ray fluxes shows that the Îł-optical correlation occurs with a time lag of Ï = -0.4+0.6-0.8 days, consistent with previous findings for this source. An analysis of 15 GHz and 43 GHz VLBI core radio flux observations in the period 2007 July-2009 February shows an increasing trend of the core radio flux, anti-correlated with the higher frequency data, allowing us to derive the value of the source magnetic field. Finally, the modeling of the broadband spectral energy distributions for the still unpublished data, and the behavior of the long-term light curves in different energy bands, allow us to compare the jet properties during different emission states, and to study the geometrical properties of the jet on a time-span longer than one year. © 2010. The American Astronomical Society. All rights reserved
Genome-wide association study of lung adenocarcinoma in East Asia and comparison with a European population
Lung adenocarcinoma is the most common type of lung cancer. Known risk variants explain only a small fraction of lung adenocarcinoma heritability. Here, we conducted a two-stage genome-wide association study of lung adenocarcinoma of East Asian ancestry (21,658 cases and 150,676 controls; 54.5% never-smokers) and identified 12 novel susceptibility variants, bringing the total number to 28 at 25 independent loci. Transcriptome-wide association analyses together with colocalization studies using a Taiwanese lung expression quantitative trait loci dataset (nâ=â115) identified novel candidate genes, including FADS1 at 11q12 and ELF5 at 11p13. In a multi-ancestry meta-analysis of East Asian and European studies, four loci were identified at 2p11, 4q32, 16q23, and 18q12. At the same time, most of our findings in East Asian populations showed no evidence of association in European populations. In our studies drawn from East Asian populations, a polygenic risk score based on the 25 loci had a stronger association in never-smokers vs. individuals with a history of smoking (Pinteractionâ=â0.0058). These findings provide new insights into the etiology of lung adenocarcinoma in individuals from East Asian populations, which could be important in developing translational applications
Expression, purification, and crystallization of two isozymes of 6-phosphoglucose isomerase of Bacillus stearothermophilus
Two isozymes of 6-phosphoglucose isomerase (phosphoglucose isomerase A & phosphoglucose isomerase B), isolated from Bacillus stearothermophilus, have been overexpressed in Escherichia coli strain DF2145 and purified to homogeneity, Crystals of both isozymes have been obtained by the vapor diffusion method. The crystals of phosphoglucose isomerase A have unit cell dimensions a = b = 132.0 Angstrom, c = 183.6 Angstrom, and diffract to about 2.8 Angstrom resolution. An analysis of the reflection data indicates that the crystal system is hexagonal, space group P6(1)22 or P6(5)22, The crystals of phosphoglucose isomerase B complexed with 6-phosphogluconate belong to the orthorhombic space group I222 (or I2(1)2(1)2(1)), With cell dimensions a = 75.1 Angstrom, b = 95.7 Angstrom, c = 171.5 Angstrom, and diffract to a resolution of 2.3 Angstrom, These crystals promise to yield more detail for the substrate recognition and higher resolution structures of 6-phosphoglucose isomerase. (C) 1997 Academic Press
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Insomniacs Misidentify Angry Faces as Fearful Faces Because of Missing the Eyes: An Eye-Tracking Study
Insomniacs were found to have compromised perception of
facial expressions. Through eye movement examinations,
here we test the hypothesis that this effect is due to impaired
visual attention functions for retrieving diagnostic features in
facial expression judgments. 23 individuals with insomnia
symptoms and 23 non-insomniac controls completed a task to
categorize happy, sad, fearful, and angry faces. The
insomniacs were less accurate to recognize angry faces and
made more âfearfulâ mistakes than controls. A hidden
Markov modeling approach for eye movement data analysis
revealed that when recognizing angry faces, more insomniacs
adopted an eye movement pattern focusing on the mouth
while more controls adopted a pattern attending to both the
eyes and the mouth. This result is consistent with previous
findings that the primary diagnostic feature for recognizing
angry faces is the eyes suggesting that impaired information
selection through visual attention control may account for the
compromised emotion perception in insomniac individuals
Mutational analysis of the conserved cationic residues of Bacillus stearothermophilus 6-phosphoglucose isomerase
The importance in catalysis of the conserved arginine (R207) and lysine residues (K144, K294, K356, and K425) of 6-phosphoglucose isomerase from Bacillus stearothermophilus was assessed by site-directed mutagenesis and kinetic analysis. In general mutations had minor effects on the K-m for fructose 6-phosphate. More dramatic effects were seen on k(cat). The R207A mutant had a five orders of magnitude decrease in k(cat) relative to the wild-type enzyme. There was a significant recovery, by three orders of magnitude, in the k(cat) for the R207K mutant. The results suggest that the positive charge provided by R207 plays a critical role in the isomerization reaction. K425 was substituted with alanine, valine, phenylalanine, tryptoplian and aspartate. All mutant enzymes at position 425 had k(cat) decreased in the range of several-hundred-fold. For the other mutants, K294A and K144A, the k(cat) values were 3.5% and 27% of the wild-type enzyme, respectively. No effects on catalysis were observed for the K356A mutant. The results suggest that R207, K144, K294, and K425 are located in the active site of the enzyme. The active-site location and the catalytic roles of K425 and K294 are supported further by the inhibitory effects of pyridoxal 5'-phosphate on enzymatic activities. The data also confirm thr importance of K425 and K144 anticipated by the affinity labeling studies of the corresponding residues by pyridoxal 5'-phosphate in pig muscle phosphoglucose isomerase
Proton pumping inorganic pyrophosphatase of endoplasmic reticulum-enriched vesicles from etiolated mung bean seedlings
Endoplasmic reticulurn (ER)-enriched vesicles from etiolated hypocotyts of mung bean seedlings (Vigna radiata) were successfully isolated using Ficoll gradient and two-phase (polyethylene glycol-dextran) partition. The ER-enriched vesicles contained inorganic pyrophosphate (PPi) hydrolysis and its associated proton translocating activities. Antiserum prepared against vacuolar H+-pyrophosphatase (V-PPase, EC 3.6.1.1) did not inhibit this novel pyrophosphatase-dependent proton translocation, excluding the possible contamination of tonoptast vesicles in the ER-enriched membrane preparation. The optimal ratios of Mg2+/PPi (inorganic pyrophosphate) for enzymatic activity and PPj-dependent proton translocation of ER-enriched vesicles were, higher than those - of vacuolar membranes. The PPj-dependent Proton translocation of ER-enriched vesicles absolutely required the presence of monovalent cations with preference for K but could be inhibited by a common PPase inhibitor, F-. Furthermore, ER H+-pyrophosphatase exhibited some similarities and differences to vacuolar H+-PPases in cofactor/substrate ratios, pH profile, and concentration dependence of F-, imidodiphosphate (a PPj anatogue), and various chemical modifiers