UNC119A Decreases the Membrane Binding of Myristoylated c‐Src

Plasma membrane localization of myristoylated c‐Src, a proto‐oncogene protein‐tyrosine kinase, is required for its signaling activity. Recent studies proposed that UNC119 protein functions as a solubilizing factor for myristoylated proteins, thereby regulating their subcellular distribution and signaling. The underlying molecular mechanism by which UNC119 regulates the membrane binding of c‐Src has remained elusive. By combining different biophysical techniques, we have found that binding of a myristoylated c‐Src‐derived N‐terminal peptide (Myr‐Src) by UNC119A results in a reduced membrane binding affinity of the peptide, due to the competition of binding to membranes. The dissociation of Myr‐Src from membranes is facilitated in the presence of UNC119A, as a consequence of which the clustering propensity of this peptide on the membrane is partially impaired. By these means, UNC119A is able to regulate c‐Src spatially in the cytoplasm and on cellular membranes, and this has important implications for its cellular signaling.     

Polydimethylsiloxane Composites for Optical Ultrasound Generation and Multimodality Imaging

Polydimethylsiloxane (PDMS) is widely used in biomedical science and can form composites that have broad applicability. One promising application where PDMS composites offer several advantages is optical ultrasound generation via the photoacoustic effect. Here, methods to create these PDMS composites are reviewed and classified. It is highlighted how the composites can be applied to a range of substrates, from micrometer‐scale, temperature‐sensitive optical fibers to centimeter‐scale curved and planar surfaces. The resulting composites have enabled all‐optical ultrasound imaging of biological tissues both ex vivo and in vivo, with high spatial resolution and with clinically relevant contrast. In addition, the first 3D all‐optical pulse‐echo ultrasound imaging of ex vivo human tissue, using a PDMS‐multiwalled carbon nanotube composite and a fiber‐optic ultrasound receiver, is presented. Gold nanoparticle‐PDMS and crystal violet‐PDMS composites with prominent absorption at one wavelength range for pulse‐echo ultrasound imaging and transmission at a second wavelength range for photoacoustic imaging are also presented. Using these devices, images of diseased human vascular tissue with both structural and molecular contrast are obtained. With a broader perspective, literature on recent advances in PDMS microfabrication from different fields is highlighted, and methods for incorporating them into new generations of optical ultrasound generators are suggested.     

Chemical investigation of eight different types of carbonaceous particles using thermoanalytical techniques

The chemical composition of ambient aerosol particles affects numerous important aerosol parameters such as their hygroscopicity, optics, and mass as well as their potentially adverse health effects. The objective of this study was to derive both detailed chemical speciation and useful proxies for the quantitative classification of the organic matter (OM) content of carbonaceous aerosol samples. Using three different thermal desorption techniques in an inert atmosphere we investigated eight different carbonaceous particulate matter (PM) samples used for health effect studies: thermal desorption gas chromatography with mass spectrometry, evolved gas analysis with mass spectrometry, and thermogravimetry with Fourier transform infrared spectroscopy. The samples include different types of laboratory-generated particles (pigment black, diffusion flame soot, spark-generated carbon) and two ambient aerosol samples (diesel soot and particulates collected in a road tunnel). All samples showed increasing mass desorption with rising temperature, but no reliable OM classification was possible based on thermal mass desorption alone. In fact, the "organic-free" spark-generated carbon particles showed the second highest mass desorption at 800 degrees C due to the formation of oxygenated structures on unsaturated surface sites and the subsequent evolution of CO and CO2 at elevated temperatures. A quantitative OM classification was accomplished by combining measurements of thermogravimetry and mass spectrometry (up to 800 degrees C) into a novel parameter, the "apparent organic mass fraction". The validity of this classification was confirmed with a second proxy parameter, based only on the evolution of organic components during thermal desorption and information on the generation process of the particles. Both types of pigment blacks (Printex) samples and the spark-generated carbon particles showed the lowest apparent organic mass fraction (< 5%), whereas for road tunnel and diesel emission particles < 16 and < 19% was estimated, respectively.     

Emergent multistability in assembled nanostructures

Scanning tunneling microscopy (STM) at 5 K reveals that native atoms in the surface layer of a semiconductor crystal become bistable in vertical height when a nanostructure is assembled nearby. The binary switching of surface atoms, driven by the STM tip, changes their charge state. Coupling is facilitated by assembling adatom chains, allowing us to explore the emergence of complex multiple switching. Density-functional theory calculations rationalize the observations and a lattice-gas model predicts the cooperative behavior from first principles.     

Zulpich箱纸板机的改造

德国Kappa Zulpich公司以前以谷草类(稻草、麦草等)作为生产原料,后改为废纸.6号纸机1996年投产,网宽为5 600mm,最高生产车速为1 000m/min,生产箱纸板和瓦楞芯纸,产量为每米工作宽度每天221t(定量为 140g/m2).     

Relation between steel/slag interfacial tension and the sulphur absorption rate in dependence of the Si and Mo concentration

The relation between the interfacial tension at the steel/slag interface and the sulphur transport through the phase boundary has been investigated. The experiments have been carried out at 1550°C. The steel/slag system consisted of Armco iron in combination with a synthetic slag containing 40% CaO, 40% SiO₂ and 20% Al₂O₃. The controlled change of the interfacial tension was performed by additional alloying of the surface active element silicon and surface inactive molybdenum. The different influences of silicon and molybdenum on interfacial tension are directly reflected by the sulphur transport rate. Higher interfacial tensions generally cause a lower sulphur transport rate. A linear relationship was only obtained in presence of silicon.     

MOLECULAR DOCKING: An example of grid enabled applications

The molecular docking web interface was developed to execute Autodock3.05 molecular docking program in the Grid environment. The nature of the application which allows the whole docking jobs to be broken up into multiple small independent tasks, has the potential of utilizing the availability of the Grid computing. Using the web interface, the whole docking procedures can be automated from the start to the end. Automation includes the preparation of the target receptor, creation of parameter files (gpf and dpf), calculation of grid energy, and docking of molecules. Once the job is split into small tasks, the tasks are submitted to Globus GRAM that submits the tasks to the resources available in the Grid environment. The execution of the grid-enabled AutoDock 3.05 is tested and the results showed that the process of molecular docking are faster compared if the execution is run on sequential computing resources.     

Synthesis and Properties of Novel Eugenol–Based Polymers

Summary This work deals with the synthesis and characterization of novel eugenol–based polymers. The polymerization of 2–methoxy–4-propenyl–1-prop–2–ynyloxybenzene (1) with Rh, Mo, and W catalysts gave the corresponding polyacetylene [poly(1)], while that using BF₃ catalyst gave poly(1), without affecting the triple bond. A novel cross–linked polyacetylene was synthesized from poly (1) with [(nbd)RhC1]₂–Et₃N catalyst.