Carotenoids are the likely precursor of a significant fraction of marine dissolved organic matter.

The ocean's biota sequester atmospheric carbon dioxide (CO2) in part by producing dissolved organic matter (DOM) that persists in the ocean for millennia. This long-term accumulation of carbon may be facilitated by abiotic and biotic production of chemical structures that resist degradation, consequently contributing disproportionately to refractory DOM. Compounds that are selectively preserved in seawater were identified in solid-phase extracted DOM (PPL-DOM) using comprehensive gas chromatography (GC) coupled to mass spectrometry (MS). These molecules contained cyclic head groups that were linked to isoprenoid tails, and their overall structures closely resembled carotenoid degradation products (CDP). The origin of these compounds in PPL-DOM was further confirmed with an in vitro β-carotene photooxidation experiment that generated water-soluble CDP with similar structural characteristics. The molecular-level identification linked at least 10% of PPL-DOM carbon, and thus 4% of total DOM carbon, to CDP. Nuclear magnetic resonance spectra of experimental CDP and environmental PPL-DOM overlapped considerably, which indicated that even a greater proportion of PPL-DOM was likely composed of CDP. The CDP-rich DOM fraction was depleted in radiocarbon (14C age > 1500 years), a finding that supports the possible long-term accumulation of CDP in seawater. By linking a specific class of widespread biochemicals to refractory DOM, this work provides a foundation for future studies that aim to examine how persistent DOM forms in the ocean

Conceptualizing soil organic matter into particulate and mineral-associated forms to address global change in the 21st century.

Managing soil organic matter (SOM) stocks to address global change challenges requires well-substantiated knowledge of SOM behavior that can be clearly communicated between scientists, management practitioners, and policy makers. However, SOM is incredibly complex and requires separation into multiple components with contrasting behavior in order to study and predict its dynamics. Numerous diverse SOM separation schemes are currently used, making cross-study comparisons difficult and hindering broad-scale generalizations. Here, we recommend separating SOM into particulate (POM) and mineral-associated (MAOM) forms, two SOM components that are fundamentally different in terms of their formation, persistence, and functioning. We provide evidence of their highly contrasting physical and chemical properties, mean residence times in soil, and responses to land use change, plant litter inputs, warming, CO2 enrichment, and N fertilization. Conceptualizing SOM into POM versus MAOM is a feasible, well-supported, and useful framework that will allow scientists to move beyond studies of bulk SOM, but also use a consistent separation scheme across studies. Ultimately, we propose the POM versus MAOM framework as the best way forward to understand and predict broad-scale SOM dynamics in the context of global change challenges and provide necessary recommendations to managers and policy makers

Impact of maximum back-EMF limits on the performance characteristics of interior permanent magnet synchronous machines

Interior permanent magnet (IPM) synchronous machines are vulnerable to uncontrolled generator (UCG) faults at high speed that can damage the inverter. One approach to reducing this risk is to impose limits on the maximum machine back-EMF voltage at top speed. This paper presents the results of a comparative design study that clarifies the nature and extent of the penalties imposed on the IPM machine metrics and performance characteristics as a result of imposing progressively tighter values of back-EMF voltage limits. As an alternative to limiting back-EMF and penalizing machine designs, this paper also investigates the effectiveness of the system-side protection approach to the same UCG fault problem.Seok-hee Han, Thomas M. Jahns, Metin Aydin, Mustafa K. Guven, Wen L. Soon

Visualization of Cytoskeletal Elements and Associated Retroviral Antigens by Immunogold Transmission Electron Microscopy of Detergent Extracted Cells

Several investigators have reported an association between the cytoskeleton and viral antigens. In our laboratory, biochemical immunofluorescence and immuno-gold electron microscopy studies were conducted on TX-100 extracted NIH/3T3 cells infected with Moloney-murine leukemia virus. Cytochalasin B treatment causes reversible microfilament disruption and a concomitant decrease in virus production. No effect on microtubules was seen. Immuno-gold electron microscopy reveals an association between cytoskeletal action and the viral antigens gp70 and p15E. The results of these immunocytological and biochemical studies indicate that the cytoskeleton may play an integral role in transport and processing of viral gene-envelope products

Enhanced magnetic response of fluids using self-assembled petal-like iron oxide particles

Using self-assembled iron oxide (SAIO) particles with petal-like morphology, aqueous fluids containing magnetic particles were prepared and the effect of hierarchical particle surface on the viscoelasticity under magnetic was investigated. The fluids consisting of self-assembled iron oxide particles exhibit highly tunable viscoelasticity which is controlled by applying external magnetic field. A difference between SAIO particles and spherical particles is explained by the fact that surface features of the self-assembled particles increased the network strength between particles in the fluids. © 2010 American Institute of Physics

Benchmarking of 3D space charge codes using direct phase space measurements from photoemission high voltage DC gun

We present a comparison between space charge calculations and direct measurements of the transverse phase space for space charge dominated electron bunches after a high voltage photoemission DC gun followed by an emittance compensation solenoid magnet. The measurements were performed using a double-slit setup for a set of parameters such as charge per bunch and the solenoid current. The data is compared with detailed simulations using 3D space charge codes GPT and Parmela3D with initial particle distributions created from the measured transverse and temporal laser profiles. Beam brightness as a function of beam fraction is calculated for the measured phase space maps and found to approach the theoretical maximum set by the thermal energy and accelerating field at the photocathode.Comment: 11 pages, 23 figures. submitted to Phys Rev ST-A

Happy Family Kitchen II, a community-based participatory research (CBPR) to enhance Family Health, Happiness and Harmony in Hong Kong: A cluster randomized control trial under FAMILY Project

Oral Poster Presentation SessionHong Kong Council of Social Service and School of Public Health, HKU conducted a three-arm cluster randomized control trial (cRCT) of a community-based participatory research (CBPR) “Happy Family Kitchen II” during July 2012 to June 2013. The present paper compared intervention arm A and control arm C to determine whether CBPR intervention improved family health, happiness and harmony (3Hs). 31 organizations in Tsuen Wan and Kwai Tsing districts were randomly allocated into: intervention arms A (n=11) and B (n=10), and waitlist control arm C (n=10).Within positive psychology and an agreed similar framework, each organization organized their own program on one selected theme of “Five-Taste Model” for people aged 6+ recruited by organization. Arm A had two intervention-sessions and one tea-gathering, and arm C had tea-gathering first (intervention at 3 months later). Participants were assessed four times (T1, pre-intervention; T2, immediately post-intervention; T3 and T4, 1 and 3 months after T2). Changes of primary outcomes from T1 to T3/T4 were compared in participants aged 12+ of arms A and C. Behavior score change was greater in arm A (n=416) than arm C (n=432) at both T3 (Effect size=0.11, p=0.03) and T4 (ES=0.21, p=0.003). Family health score and happiness score changes were greater in arm A than arm C at T3, with ES=0.23 (p=0.001) and ES=0.18 (p=0.01) respectively. Mental health score and intention score changes were greater in arm A than arm C at T4, with ES=0.16 (p=0.03) and ES=0.18 (p=0.01) respectively. All changes above indicated improvements in outcomes. This was the first cRCT to evaluate a CBPR short intervention in Hong Kong, which was effective with small effect size in increasing participants’ intention and practice in healthy behaviors and improving family 3Hs, suggesting that CBPR, evidence-based and evidence-generating programmes are feasible and effective.postprin