Polyelectrolyte flexibility effect on the morphology of charged lipid multilayers

Coupling of flexible (PAAS: polyacrylic acid sodium salt) and semiflexible (λ DNA) polyelectrolytes onto an oppositely charged lipid monolayer (DOTAP: dioleoyl trimethylammonium propane chloride) at the air-liquid interface leads distinctive collapse behavior with lateral compression. In both cases, trilayer domains form by nucleation growth mechanism followed by multilayer formation with further compression. The flexible chain induces circular, fluid domains while the semiflexible chain induces elongated, solid-like domains. These morphological differences show that the flexibility of adsorbed polymers strongly affects the rigidity of the lipid membrane

Thickness dependence of surface modes on a gel

A surface wave mode on a gel has been studied as a function of thickness by using electrically excited surface wave spectroscopy (EESWS), which measures the response of excited surface waves by applying an electric field at the surface. In the frequency region where the elastic and surface tension forces dominate, multiple harmonics of a surface mode are predicted theoretically for a finite-thickness case due to a coupling with the normal direction wave to the surface. This paper shows the first experimental measurement of the multiple harmonics of a surface mode. We have compared the experimental data with the theoretical calculation

Genome-Wide Identification and Characterization of Warming-Related Genes in Brassica rapa ssp. pekinensis

For sustainable crop cultivation in the face of global warming, it is important to unravel the genetic mechanisms underlying plant adaptation to a warming climate and apply this information to breeding. Thermomorphogenesis and ambient temperature signaling pathways have been well studied in model plants, but little information is available for vegetable crops. Here, we investigated genes responsive to warming conditions from two Brassica rapa inbred lines with different geographic origins: subtropical (Kenshin) and temperate (Chiifu). Genes in Gene Ontology categories “response to heat”, “heat acclimation”, “response to light intensity”, “response to oxidative stress”, and “response to temperature stimulus” were upregulated under warming treatment in both lines, but genes involved in “response to auxin stimulus” were upregulated only in Kenshin under both warming and minor-warming conditions. We identified 16 putative high temperature (HT) adaptation-related genes, including 10 heat-shock response genes, 2 transcription factor genes, 1 splicing factor gene, and 3 others. BrPIF4, BrROF2, and BrMPSR1 are candidate genes that might function in HT adaptation. Auxin response, alternative splicing of BrHSFA2, and heat shock memory appear to be indispensable for HT adaptation in B. rapa. These results lay the foundation for molecular breeding and marker development to improve warming tolerance in B. rapa

Ultrahigh-throughput screening in drop-based microfluidics for directed evolution

The explosive growth in our knowledge of genomes, proteomes, and metabolomes is driving ever-increasing fundamental understanding of the biochemistry of life, enabling qualitatively new studies of complex biological systems and their evolution. This knowledge also drives modern biotechnologies, such as molecular engineering and synthetic biology, which have enormous potential to address urgent problems, including developing potent new drugs and providing environmentally friendly energy. Many of these studies, however, are ultimately limited by their need for even-higher-throughput measurements of biochemical reactions. We present a general ultrahigh-throughput screening platform using drop-based microfluidics that overcomes these limitations and revolutionizes both the scale and speed of screening. We use aqueous drops dispersed in oil as picoliter-volume reaction vessels and screen them at rates of thousands per second. To demonstrate its power, we apply the system to directed evolution, identifying new mutants of the enzyme horseradish peroxidase exhibiting catalytic rates more than 10 times faster than their parent, which is already a very efficient enzyme. We exploit the ultrahigh throughput to use an initial purifying selection that removes inactive mutants; we identify ∼100 variants comparable in activity to the parent from an initial population of ∼10 [superscript 7]. After a second generation of mutagenesis and high-stringency screening, we identify several significantly improved mutants, some approaching diffusion-limited efficiency. In total, we screen ∼10 [superscript 8] individual enzyme reactions in only 10 h, using < 150 μL [mu L] of total reagent volume; compared to state-of-the-art robotic screening systems, we perform the entire assay with a 1,000-fold increase in speed and a 1-million-fold reduction in cost.Human Frontier Science Program (Strasbourg, France) (Grant RGP0004/2005-C102)National Science Foundation (U.S.) (Grant DMR-0602684) (Grant DBI-0649865)Harvard University. Materials Research Science and Engineering Center (DMR- 0820484)Massachusetts Life Sciences CenterFrance. Agence nationale de la recherche (ANR-05- BLAN-0397

Additional file 1: of Prognostic values of negative estrogen or progesterone receptor expression in patients with luminal B HER2-negative breast cancer

Result of statistic analysis. (DOCX 389 kb

Biofunctionalized Ceramic with Self-Assembled Networks of Nanochannels

Nature designs circulatory systems with hierarchically organized networks of gradually tapered channels ranging from micrometer to nanometer in diameter. In most hard tissues in biological systems, fluid, gases, nutrients and wastes are constantly exchanged through such networks. Here, we developed a biologically inspired, hierarchically organized structure in ceramic to achieve effective permeation with minimum void region, using fabrication methods that create a long-range, highly interconnected nanochannel system in a ceramic biomaterial. This design of a synthetic model-material was implemented through a novel pressurized sintering process formulated to induce a gradual tapering in channel diameter based on pressure-dependent polymer agglomeration. The resulting system allows long-range, efficient transport of fluid and nutrients into sites and interfaces that conventional fluid conduction cannot reach without external force. We demonstrate the ability of mammalian bone-forming cells placed at the distal transport termination of the nanochannel system to proliferate in a manner dependent solely upon the supply of media by the self-powering nanochannels. This approach mimics the significant contribution that nanochannel transport plays in maintaining living hard tissues by providing nutrient supply that facilitates cell growth and differentiation, and thereby makes the ceramic composite “alive”