Direct profiling of lipid distribution in brain tissue using MALDI-TOFMS

Recent developments in mass spectrometry have permitted direct analysis of biomolecules in tissue. However, most studies have focused on proteins with emphasis on biomarker discovery. In the present work, matrix-assisted laser desorption/ionization mass spectrometry was used for the direct analysis of lipids in rat cerebellum. The lipid bilayer role as a storage depot for small organic molecules such as therapeutic drugs and pollutants such as DDT, as well as the ability to compare lipid profiles in healthy and diseased animal models, are a few of the many reasons why the direct probing of tissue to determine the qualitative and possibly quantitative lipid content could be a very useful tool. Molecular ions corresponding to cholesterol, phosphatidylcholines, sphingomyelins, and phosphatidylethanolamines were recorded in positive ion mode, while ones corresponding to phosphatidylinositols, sulfatides, and gangliosides were recorded in negative ion mode. Overall, representatives from all major categories of brain lipids including cholesterol, 15 phospholipid species (9 phosphatidylcholines, 1 sphingomyelin, 3 phosphatidylethanolamines, 2 phosphatidylinositols), 10 sulfatides (5 hydroxylated species and 5 nonhydroxylated species), and 7 species of gangliosides were detected.     

A review on (Sr,Ca)TiO3-based dielectric materials: crystallography,recent progress and outlook in energy-storage aspects

Journal of Materials Science - In pursuit of developing high-performance lead-free energy storage capacitors, strontium titanate (SrTiO3) and calcium titanate (CaTiO3) are widely recognised as...     

Prefix-projection global constraint and top-<Emphasis Type="Italic">k</Emphasis> approach for sequential pattern mining

Sequential pattern mining (SPM) is an important data mining problem with broad applications. SPM is a hard problem due to the huge number of intermediate subsequences to be considered. State of the art approaches for SPM (e.g., PrefixSpan Pei et al. 2001) are largely based on the pattern-growth approach, where for each frequent prefix subsequence, only its related suffix subsequences need to be considered, and the database is recursively projected into smaller ones. Many authors have promoted the use of constraints to focus on the most promising patterns according to the interests of the end user. The top-k SPM problem is also used to cope with the difficulty of thresholding and to control the number of solutions. State of the art methods developed for SPM and top-k SPM, though efficient, are locked into a rather rigid search strategy, and suffer from the lack of declarativity and flexibility. Indeed, adding new constraints usually amounts to changing the data-structures used in the core of the algorithm, and combining these new constraints often require new developments. Recent works (e.g. Kemmar et al. 2014; Négrevergne and Guns 2015) have investigated the use of Constraint Programming (CP) for SPM. However, despite their nice declarative aspects, all these modelings have scaling problems, due to the huge size of their constraint networks. To address this issue, we propose the Prefix-Projection global constraint, which encapsulates both the subsequence relation as well as the frequency constraint. Its filtering algorithm relies on the principle of projected databases which allows to keep in the variables domain, only values leading to a frequent pattern in the database. Prefix-Projection filtering algorithm enforces domain consistency on the variable succeeding the current frequent prefix in polynomial time. This global constraint also allows for a straightforward implementation of additional constraints such as size, item membership, regular expressions and any combination of them. Experimental results show that our approach clearly outperforms existing CP approaches and competes well with the state-of-the-art methods on large datasets for mining frequent sequential patterns, sequential patterns under various constraints, and top-k sequential patterns. Unlike existing CP methods, our approach achieves a better scalability.     

Radar and optical mapping of surge persistence and marsh dieback along the New Jersey Mid-Atlantic coast after Hurricane Sandy

This study combined a radar-based time series of Hurricane Sandy surge and estimated persistence with optical sensor-based marsh condition change to assess potential causal linkages of surge persistence and marsh condition change along the New Jersey Atlantic Ocean coast. Results based on processed TerraSAR-X and COSMO-SkyMed synthetic aperture radar (SAR) images indicated that surge flooding persisted for 12 h past landfall in marshes from Great Bay to Great Egg Harbor Bay and up to 59 h after landfall in many back-barrier lagoon marshes. Marsh condition change (i.e. loss of green marsh vegetation) was assessed from optical satellite images (Satellite Pour l’Observation de la Terre and Moderate Resolution Imaging Spectroradiometer) collected before and after Hurricane Sandy. High change in condition often showed spatial correspondence, with high surge persistence in marsh surrounding the lagoon portion of Great Bay, while in contrast, low change and high persistence spatial correspondence dominated the interior marshes of the Great Bay and Great Egg Harbor Bay estuaries. Salinity measurements suggest that these areas were influenced by freshwater discharges after landfall possibly mitigating damage. Back-barrier marshes outside these regions exhibited mixed correspondences. In some cases, topographic features supporting longer surge persistence suggested that non-correspondence between radar and optical data-based results may be due to differential resilience; however, in many cases, reference information was lacking to determine a reason for non-correspondence.     

Sulfur‐Mastery: Precise Synthesis of 2D Transition Metal Dichalcogenides

Chemical vapor deposition (CVD) has been developed as the most promising method for the growth of transition metal dichalcogenides (TMDs). In this work, the key factor determining the growth of TMDs is ascertained. A straightforward method is devised to directly achieve a holistic control of thickness, shape, and size of WS₂ flakes via a single parameter control, namely, the status of the S‐precursor. The thickness‐dependent growth of WS₂ flakes from mono‐ to quad‐layers is achieved by precise control of the feeding rate of elemental S‐precursor. Moreover, the explicit control over amount and exposure time of S‐precursor determines the most optimum combination of these parameters to tune the shape of the crystals from triangular to hexagonal with appropriate size. Hence, the experimental findings provide a promising strategy to engineer the growth evolution of WS₂ atomic layers by fine tuning of the sulfur supply, paving a pathway to scalable electronic and photonic devices.     

Assessment of wheelchair skills based on analysis of driving style

In this paper, we propose a learning assessment method based on the analysis of learner’s behavioural style. This method was first applied for wheel-chair driving tasks because it is simple and risk-free, but unusual for users. Seven classic performance indicators based on joystick control were used to characterise the users’ driving style. We assumed that the learning effectiveness of the users can be evaluated by comparing their driving style with the reference ones, which could be extracted from experienced users. The evaluation was carried out for six novice users and eight experienced users. The users were asked to carry out several typical driving tasks for seven trials at first. The fuzzy C-means clustering method was used with the data of the experienced users to obtain the reference driving styles. Next, an evaluation was performed for novice users by comparing their driving styles with the reference ones. The results showed that, for all of the experienced users, their driving styles could be classified into two reference types. In addition, there was no significant difference in their driving styles from one trial to another, even for a user with disabilities, which means that their driving style was stable. On the other hand, novice users had switching behaviours during the learning phase; however, after eight additional trials, each novice user’s driving style converged to one of the two identified reference types, meaning that the novice users could achieve a stable performance after learning, which was also validated by an expert therapist.     

New efficient M2C and M2M mutual authentication protocols for IoT-based healthcare applications

Peer-to-Peer Networking and Applications - With the rapid advancement of heterogeneous wireless technologies and their proliferation in ambient connected objects, the Internet of Things (IoT) is a...     

Phototransformation of metobromuron in the presence of TiO2

The photocatalytic degradation of the herbicide metobromuron was studied, using TiO₂ photocatalysts (Degussa P25 and Millennium PC50, PC100, PC105 and PC500). Intermediate products were identified by means of liquid chromatography–mass spectrometry (LC–MS–MS) using electrospray (ES) interfacing technique. In order of importance, the main reaction pathways were demethoxylation of the urea chain, ring oxidation leading to ortho hydroxylation with respect to the N atom, substitution of Br by OH, ring oxidation with formation of the meta hydroxylated compound. Demethylation of the demethoxylated product occurred as a secondary reaction. Formation of bromide ions was observed too. In the presence of 2-propanol used as a hydroxyl radical scavenger, demethoxylation was drastically inhibited while the other reactions were only partly inhibited. It suggests that demethoxylation was exclusively due to the oxidation by hydroxyl radicals, whereas the other reactions involved positive holes too. The degradation rate of metobromuron varied in the order: PC50 < PC100 < PC105 < PC500 < Degussa P25. TiO₂ Degussa P25 was therefore the most efficient photocatalyst although its surface area was lower than that of most of Millennium TiO₂.     

Fatty Acids Profile and Chemical Composition of Egyptian Moringa oleifera Seed Oils

Moringa oleifera is grown all over the world as a crop for its nutritious pods, leaves and seeds. The purpose of the present study was to evaluate the oil percentage, density, iodine value, saponification value, acid value and fatty acid profile of Egyptian moringa Seed oils. Moringa seeds were irradiated using ⁶⁰Co at dose levels of 0.0 (control), 5, 10 and 15 kGy and oil was extracted from unirradiated and irradiated samples. Results showed that the oil percentage and density were almost unaffected. Irradiation reduced the iodine value, whereas the acid and saponification values were increased in all irradiated samples. The oil was found to contain high levels of unsaturated fatty acids, especially an omega‐9‐fatty acid (oleic) (up to 76.29 %) at a dose level of 15 kGy. Also at the same dose level, the dominant saturated acids were palmitic, stearic acid and arachidic (the three up to 12.66 %). GC–MS revealed the presence of different compounds (more than 50) in the moringa oil extract, among them alkaloids, terpenoids steroids, saturated and unsaturated fatty acids, aromatic and aliphatic hydrocarbons and polyphenolic compounds. Phenolic and falvonoid were significantly increased by increasing irradiation dose levels. Also, the antioxidant activity of irradiated seed oil increased by increasing the phenolic and flavonoid contents. Moringa oleifera could be grown by wide scale production as a potentially valuable crop. However, isolation of individual compounds and their biological activities needs to be covered in future to enhance its pharmacological importance and to open new avenues of research.