Corrosion protection of aluminum 6061 in NaCl solution by silane–zeolite composite coatings

Anticorrosion properties of silane?Czeolite composite coatings applied on aluminum substrates have been investigated. The composite coatings were prepared with different zeolite microparticles concentration (from 500 to 8000?ppm). Physico-chemical tests (Fourier transform infrared spectroscopy, adhesion, scanning electron microscopy, and contact angle measurements) have been carried out to evaluate the homogeneity and structural properties of the coatings. The coatings that resulted were highly hydrophobic for all zeolite contents and showed a relatively good adhesion performance. Corrosion protection performances in 3.5% NaCl solution were evaluated by means of polarization tests, evidencing good barrier characteristics of the composite layer.     

Volatiles Emission Patterns in Poplar Clones Varying in Response to Ozone

The volatiles emitted from young and old leaves of two poplar clones (Populus deltoides x maximowiczii, Eridano, and P. x euramericana, I-214) were sampled after exposure to ozone (80 ppb, 5 h?d(-1), for 10 consecutive days) by solid phase microextraction and characterized by GC-MS. Only mature leaves of the ozone-sensitive Eridano clone developed necrosis in response to ozone exposure, and their membrane integrity was significantly affected by ozone (+86 and +18 % of levels of thiobarbituric acid reactive substances in mature and young leaves). The headspace of the poplar clones studied here contained mono- and sesquiterpenes, both hydrocarbons and oxygenated ones in Eridano, and only hydrocarbons in the clone I-214. Furthermore, some non-terpenes, such as C(9)-C(15) straight-chain aldehydes and C(12)-C(16) saturated and unsaturated aliphatic hydrocarbons, were detected. Other common non-terpene volatiles were oxygenated aliphatic compounds, mainly C(6)-alcohols and their acetates. Ozone exposure induced a strong change in volatile profiles, depending on clones and leaf age. Regardless of leaf age, in clone I-214, quantities of oxygenated monoterpenes tended to increase after ozone exposure, however, "O(3) x leaf age" was not significant. In clone Eridano, increases were observed in emissions of hydrocarbons and oxygenated sesquiterpenes in response to ozone treatment. (Z)-3-Hexen-1-ol and (Z)-3-hexenol acetate were present in traces in the headspace of untreated Eridano mature leaves, but quantities slightly increased after ozone treatment. Quantities of non-terpene oxygenated compounds dropped in the headspace of young leaves of both clones (-24 and -44 % in Eridano and I-214) and also in mature ones of I-214 (-50 %) after ozone exposure. Similarly, quantities of non-terpene hydrocarbons in the emissions from mature leaves of both clones (-58 and -49 %, respectively) decreased, while these compounds increased in young leaves of Eridano (+83 %). We suggest that the resistance of the poplar clone I-214 to O(3) is achieved by: i) monoterpenes constitutively present in young leaves and ii) increase of monoterpene content induced by O(3) in mature leaves.     

β-D-Glucosyl Conjugates of Highly Potent Inhibitors of Blood Coagulation Factor Xa Bearing 2-Chorothiophene as a P1 Motif

We synthesized a novel O‐glucoside of the recently reported potent factor Xa (fXa) inhibitor 1 , which bears a 5‐chlorothien‐2‐yl moiety and 1‐isopropylpiperidine as fragments that bind the S1 and S4 enzyme pockets, respectively. A β‐D ‐glucosyl unit was conjugated through an ether‐linked C3‐alkyl spacer to the central phenyl ring of 1 . The synthesized β‐D ‐glucose‐based compound 16 achieved picomolar inhibitory potency against human fXa (K_i=60 pM ) and high selectivity over thrombin and other serine proteases. In addition to the chlorothienyl S1 binder, a large gain in ΔG resulted from the addition of protonated 1‐isopropylpiperidine (ΔΔG=29.7–30.5 kJ mol^?1), which should bind to the aromatic S4 pocket through efficient cation–π and C? H???π interactions. Instead, the C3‐alkyl‐linked glucose fragment, which is likely directed toward the solvent outside the enzyme binding site, improves ΔG by an average of 2.9–3.8 kJ mol^?1. Compound 16 showed sub‐micromolar in vitro anticoagulant activity, as assessed by prothrombin time (PT) and activated thromboplastin time (aPTT) clotting assays in pooled human plasma (PT₂ and aPTT₂ equal to 0.135 and 0.389 μM , respectively). Although compound 16 was 1.4‐fold less active than parent compound 1 in the ex vivo anticoagulant assay in mice, it showed a significant (1.6‐fold) prolongation of PT relative to controls (P<0.05) 60 min after oral dosing (75 mg kg^?1).     

Determination of Homoarginine,Arginine, NMMA,ADMA, and SDMA in Biological Samples by HPLC-ESI-Mass Spectrometry

N^G,N^G-dimethyl-l-arginine (ADMA) and N^G-methyl-l-arginine (NMMA) are endogenous inhibitors of nitric oxide synthase (NOS). In contrast, N^G,N′^G-dimethyl-Larginine (SDMA) possesses only a weak inhibitory potency towards neuronal NOS and it is known to limit nitric oxide (NO) production by competing with l-arginine for cellular uptake. The inhibition of NOS is associated with endothelial dysfunction in cardiovascular diseases as well in chronic renal failure. l-Homoarginine (HArg), a structural analog of l-arginine (Arg), is an alternative but less efficient substrate for NOS. Besides, it inhibits arginase, leading to an increased availability of l-arginine for NOS to produce NO. However, its relation with cardiovascular disease remains unclear. To date, several analytical methods for the quantitative determination of Arg, HArg, NMMA, AMDA, and SDMA in biological samples have been described. Here, we present a simple, fast, and accurate HPLC-ESI-MS/MS method which allows both the simultaneous determination and quantification of these compounds without needing derivatization, and the possibility to easily modulate the chromatographic separation between HArg and NMMA (or between SDMA and ADMA). Data on biological samples revealed the feasibility of the method, the minimal sample preparation, and the fast run time which make this method very suitable and accurate for analysis in the basic and clinical settings.     

Estimating Reduced-Reference Video Quality for Quality-Based Streaming Video

Reduced-reference (RR) video-quality estimators send a small signature to the receiver. This signature comprises the original video content as well as the video stream. RR quality estimation provides reliability and involves a small data payload. While significant in theory, RR estimators have only recently been used in practice for quality monitoring and adaptive system control in streaming-video frameworks. In this paper, we classify RR algorithms according to whether they are based on a) modeling the signal distortion, b) modeling the human visual system, or c) analyzing the video signal source. We review proposed RR techniques for monitoring and controlling quality in streaming video systems.     

Abelmoschus esculentus (L.) Moench. and Abelmoschus moschatus Medik: Seeds production and analysis of the volatile compounds

Nine accessions of Abelmoschus esculentus (L.) Moench. and three of Abelmoschus moschatus Medik were both grown in Central Italy for the evaluation of the production of seeds. Furthermore, the volatiles emitted by the mature seeds were sampled by mean of SPME. Seventy compounds were detected in the headspace of the seeds of A. esculentus. The principal constituents common to all the nine accessions were isopentyl 2-methyl butanoate (24.5–59.1%) and heptanoic acid 2-methylbutyl ester (6.6–13.5%). In the headspace around the seeds of A. moschatus 93 components were detected. Among the main volatiles shared by the three accessions, n-tridecane (1.5–26.9%), isopentyl 2-methyl butanoate (0.2–14.3%) and decanal (1.6–5.7%) should be mentioned. Many differences were present in the volatiles emitted by the various accessions and between the two Abelmoschus species.     

Adaptive appearance modeling for video tracking: survey and evaluation

Long-term video tracking is of great importance for many applications in real-world scenarios. A key component for achieving long-term tracking is the tracker's capability of updating its internal representation of targets (the appearance model) to changing conditions. Given the rapid but fragmented development of this research area, we propose a unified conceptual framework for appearance model adaptation that enables a principled comparison of different approaches. Moreover, we introduce a novel evaluation methodology that enables simultaneous analysis of tracking accuracy and tracking success, without the need of setting application-dependent thresholds. Based on the proposed framework and this novel evaluation methodology, we conduct an extensive experimental comparison of trackers that perform appearance model adaptation. Theoretical and experimental analyses allow us to identify the most effective approaches as well as to highlight design choices that favor resilience to errors during the update process. We conclude the paper with a list of key open research challenges that have been singled out by means of our experimental comparison.     

An open and scalable architecture for delivering 3D shared visualization services to heterogeneous devices

Shared visualization environments represent an effective means to enhance collaborative work in engineering and scientific design tasks. The availability of high‐speed networks allows researchers to work together from geographically distributed locations, and mobile devices are able to carry out ubiquitous 3D visualization tasks through wireless network connections. This paper presents a scalable architecture for the delivery of shared 3D visualization services to heterogeneous terminals ranging from powerful workstations to mobile devices such as PDAs and smart‐phones. The framework design allows both desktop and mobile clients to simultaneously visualize the same model by sharing a common view. Remote‐rendering servers support effective visualization on thin clients, and a load balancing mechanism provides efficient resource usage. Copyright © 2011 John Wiley & Sons, Ltd.