A fabrication history based strain-fatigue model for prediction of crack initiation in a radial loading wheel

A strain-based fatigue model concerning fabrication history is applied to predict the fatigue life of a commercial car wheel under radial loads. As the prior conditions, the strain fatigue testing is performed on standard specimen of DP590 and FB540 steels at various fabrication states, including raw materials, pre-strain and pre-strain + bake. Furthermore, the strain distribution of car wheel during its rotation under radial loads is simulated via ANSYS. The fatigue properties mainly determined by crack initiation of car wheels at various fabrication states are predicted via local stress–strain method, in which the scale and surface factors are also taken into account. The radial fatigue testing is carried out, and the results are used to validate the present model. The fracture mechanism is analysed using FEI Nova 400 field emission gun scanning electron microscope

Assessment of β-D-Glucosidase Activity from Two Typical Strains of the Lactic Acid Bacteria, Oenococcus oeni, in China

β-D-glucosidase (βG) is one of the most interesting glycosidases for the hydrolysis of glycoconjugatedprecursors to release active aromatic compounds in musts and wines. Oenococcus oeni strains SD-2a and31MBR are widely used in Chinese wines to reduce the acidity. In the present study, the βG activity of thetwo strains was localised and partially characterised using synthetic substrate. The activity occurred inwhole cells, sonication supernatants and debris, but not in the culture supernatants for both strains. Wholecells of strain SD-2a possessed greater βG activity, while strain 31MBR showed higher enzyme activity inthe sonication supernatants. Strain 31MBR exhibited higher total enzyme activity than strain SD-2a. Theoptimum temperatures for βG from the two strains were 40ºС at pH 3.5 and 50ºС at pH 5.0, respectively.Ethanol at low concentrations had a positive effect on βG activity in both strains, while a wine-like pH (3.5)decreased the enzyme activity to a great extent. Whole cells of strain SD-2a showed the highest activityamong all samples tested under wine-like conditions. Thus, strain SD-2a proved to have potential foraroma improvement in winemaking

Antibiotics Alter Pocillopora Coral-Symbiodiniaceae-Bacteria Interactions and Cause Microbial Dysbiosis During Heat Stress

Symbioses between eukaryotes and their associated microbial communities are fundamental processes that affect organisms’ ecology and evolution. A unique example of this is reef-building corals that maintain symbiotic associations with dinoflagellate algae (Symbiodiniaceae) and bacteria that affect coral health through various mechanisms. However, little is understood about how coral-associated bacteria communities affect holobiont heat tolerance. In this study, we investigated these interactions in four Pocillopora coral colonies belonging to three cryptic species by subjecting fragments to treatments with antibiotics intended to suppress the normal bacteria community, followed by acute heat stress. Separate treatments with only antibiotics or heat stress were conducted to compare the effects of individual stressors on holobiont transcriptome responses and microbiome shifts. Across all Pocillopora species examined, combined antibiotics and heat stress treatment significantly altered coral-associated bacteria communities and caused major changes in both coral and Cladocopium algal symbiont gene expression. Individually, heat stress impaired Pocillopora protein translation and activated DNA repair processes, while antibiotics treatments caused downregulation of Pocillopora amino acid and inorganic ion transport and metabolism genes and Cladocopium photosynthesis genes. Combined antibiotics-heat stress treatments caused synergistic effects on Pocillopora and Cladocopium gene expression including enhanced expression of oxidative stress response genes, programed cell death pathways and proteolytic enzymes that indicate an exacerbated response to heat stress following bacteria community suppression. Collectively, these results provide further evidence that corals and their Symbiodiniaceae and bacteria communities engage in highly coordinated metabolic interactions that are crucial for coral holobiont health, homeostasis, and heat tolerance

Semiconductor-metal core-shell plasmonic nanolasers with a bowtie antenna cross section

A new plasmonic bowtie nanolaser structure is fabricated where a semiconductor gain core is enclosed by a metal shell with bowtie cross section built-in. Light emission characteristics under electrical injection will be reported

All-optical header processor for packet switched networks

A serial all-optical header processing technique is presented that is based on the two-pulse correlation principle in a SLALOM configuration. The operation is demonstrated using optical data packets with a packet header at 2.5 Gbit/s and Manchester encoded packet payload at 10 Gbit/s. Experimental evidence is provided in the case of two different output ports. A Bragg grating assisted all-optical header pre-processor based on self-phase modulation in a semiconductor optical amplifier is also presented. It is shown that the header pre-processor improves the performance of the SLALOM-based header processor and that the packet structure can be simplified

Optical flip-flop memory based on ring lasers sharing one active element with feedback through an extended cavity

We present a novel optical flip-flop configuration that consists of two unidirectional ring lasers with separate cavities but sharing the same active element unidirectionally. We show that in such a configuration light in the lasing cavity can suppress lasing in the other cavity so that this system forms an optical bistable element. Essential for obtaining the bistability is the presence of an additional feedback circuit that is shared by both lasers. We show experimentally that the flip-flop can be optically set and reset, has a contrast ratio of 40 dB and allows low optical power operation. We also present a model based on roundtrip equations. Good agreement between theory and experiments is obtained

1x2 optical packet switch using all-optical header processing

A 1×2 all-optical packet switch is presented. The header processing is implemented by using a SLALOM structure and an optical flip-flop memory is used to store the processed header bits. The packets are switched in wavelength by using cross-gain modulation. Experimental results are presente

Peptide-mediated growth and dispersion of Au nanoparticles in water via sequence engineering

YesThe use of peptides to nucleate, grow, and stabilize nanoparticles in aqueous media via non-covalent interactions offers new possibilities for creating functional, water-dispersed inorganic/organic hybrid materials, particularly for Au nanoparticles. Numerous previous studies have identified peptide sequences that both possess a strong binding affinity for Au surfaces and are capable of supporting nanoparticle growth in water. However, recent studies have shown that not all such peptide sequences can produce stable dispersions of these nanoparticles. Here, via integrated experiments and molecular modeling, we provide new insights into the many factors that influence Au nanoparticle growth and stabilization in aqueous media. We define colloidal stability by the absence of visible precipitation after at least 24 hours post-synthesis. We use binding affinity measurements, nanoparticle synthesis, characterization and stabilization assays, and molecular modeling, to investigate a set of sequences based on two known peptides with strong affinity for Au. This set of biomolecules is designed to probe specific sequence and context effects using both point mutations and global reorganization of the peptides. Our data confirm, for a broader range of sequences, that Au nanoparticle/peptide binding affinity alone is not predictive of peptide-mediated colloidal stability. By comparing nanoparticle stabilization assay outcomes with molecular simulations, we establish a correlation between the colloidal stability of the Au nanoparticles and the degree of conformational diversity in the surface-adsorbed peptides. Our findings suggest future routes to engineer peptide sequences for bio-based growth and dispersion of functional nanoparticles in aqueous media.Air Office of Scientific Research, grant number FA9550-12-1-0226

Energy band structure and intrinsic coherent properties in two weakly linked Bose Einstein Condensates

The energy band structure and energy splitting due to quantum tunneling in two weakly linked Bose-Einstein condensates were calculated by using the instanton method. The intrinsic coherent properties of Bose Josephson junction were investigated in terms of energy splitting. For $E_{C}/E_{J}\ll 1$, the energy splitting is small and the system is globally phase coherent. In the opposite limit, $E_{C}/E_{J}\gg 1$, the energy splitting is large and the system becomes a phase dissipation. Our reslults suggest that one should investigate the coherence phenomna of BJJ in proper condition such as $E_{C}/E_{J}\sim 1$.Comment: to appear in Phys. Rev. A, 2 figure