Publications

Overlapping Photoprotective Function of Vitamin E and Carotenoids in<i>Chlamydomonas</i>     

Abstract Tocopherols (vitamin E) and carotenoids are the two most abundant groups of lipid-soluble antioxidants in the chloroplast. Carotenoids are well known for their roles in protecting against photooxidative stress, whereas the photoprotective functions of tocopherols have only recently been examined experimentally. In addition, little is known about the functional overlap of carotenoids and tocopherols in vivo. To investigate this possible overlap, Chlamydomonas reinhardtii strains were engineered to overproduce tocopherols by chloroplast transformation with non-codon-optimized and codon-optimized versions of the homogentisate phytyltransferase vitamin E2 (VTE2) from Synechocystis and by nuclear transformation with VTE2 from C. reinhardtii, which resulted in 1.6-fold, 5-fold to 10-fold, and more than 10-fold increases in total tocopherol content, respectively. To test if tocopherol overproduction can compensate for carotenoid deficiency in terms of antioxidant function, the nuclear VTE2 gene from C. reinhardtii was overexpressed in the npq1 lor1 double mutant, which lacks zeaxanthin and lutein. Following transfer to high light, the npq1 lor1 strains that overaccumulated tocopherols showed increased resistance for up to 2 d and higher efficiency of photosystem II, and they were also much more resistant to other oxidative stresses. These results suggest an overlapping functions of tocopherols and carotenoids in protection against photooxidative stress.

GRB 190630C: KAIT Optical Upper Limit

Simultaneous Electrostatic and Magnetic Vector Potential Phase Retrieval Using Electron Ptychography

While the observation of magnetic structure with nanometer spatial resolution has been successfully achieved with various transmission electron microscopy (TEM) techniques such as Lorentz TEM, off-axis electron holography, differential phase contrast (DPC), and more recently, Lorentz scanning TEM, atomic-scale imaging of magnetization remains challenging.This can be traced back to the extremely small phase-shifts acquired by the electron beam due to the magnetic vector potential, A(x, y, z), compared to those acquired due to the electrostatic potential of the sample, V(x, y, z): φ(x, y) = φ e (x, y) + φ m (x, y) = σ ∫ V(x, y, z)dze h -∫ A z (x, y, z)dz,

Ligand-Controlled Access to [4 + 2] and [4 + 3] Cycloadditions in Gold-Catalyzed Reactions of Allene-Dienes

By adjustment of the electronic properties of the ancilliary ligands, high selectivity can be achieved for either [4 + 2] or [4 + 3] cycloaddition reactions of allene-dienes catalyzed by gold(I). Triarylphosphitegold(I) complexes are employed as catalysts for a [4 + 2] cycloaddition reaction leading to alkylidenecyclohexenes. Conversely, di-tert-butylbiphenylphosphinegold(I)-catalyzed reactions afford cycloheptadienes via [4 + 3] cycloaddition reactions.

Internet-delivered cognitive-behavioral therapy for insomnia and comorbid symptoms

CCDC 942869: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Feedstocks for Lignocellulosic Biofuels

In 2008, the world produced approximately 87 gigaliters of liquid biofuels, which is roughly equal to the volume of liquid fuel consumed by Germany that year. Essentially, all of this biofuel was produced from crops developed for food production, raising concerns about the net energy and greenhouse gas effects and potential competition between use of land for production of fuels, food, animal feed, fiber, and ecosystem services. The pending implementation of improved technologies to more effectively convert the nonedible parts of plants (lignocellulose) to liquid fuels opens diverse options to use biofuel feedstocks that reach beyond current crops and the land currently used for food and feed. However, there has been relatively little discussion of what types of plants may be useful as bioenergy crops.

Regulation of photosystem stoichiometry and relation to chloroplast ultrastructure

Learning Appearance Based Models: Mixtures of Second Moment Experts

This paper describes a new technique for object recognition based on learning appearance models. The image is decomposed into local regions which are described by a new texture representation called &amp;quot;Generalized Second Moments &amp;quot; that are derived from the output of multiscale, multiorientation filter banks. Class-characteristic local texture features and their global composition is learned by a hierarchical mixture of experts architecture (Jordan &amp;amp; Jacobs). The technique is applied to a vehicle database consisting of 5 general car categories (Sedan, Van with back-doors, Van without back-doors, old Sedan, and Volkswagen Bug). This is a difficult problem with considerable in-class variation. The new technique has a 6:5% misclassification rate, compared to eigen-images which give 17:4% misclassification rate, and nearest neighbors which give 15:7% misclassification rate. 1 Introduction Until a few years ago neural network and other statistical learning techniques were not very...

Pd‐Catalyzed α‐Arylation of Trimethylsilyl Enol Ethers with Aryl Bromides and Chlorides: A Synergistic Effect of Two Metal Fluorides as Additives

The long-sought-after palladium-catalyzed coupling of silyl enol ethers, both cyclic and acyclic, with a wide range of aryl bromides and chlorides to form α-aryl ketones is realized. The key to effective activation of the silicon enolate was the use of two metal fluoride additives, which operate in a synergistic fashion. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2006/z601887_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Zirconacyclopentadiene‐Annulated Polycyclic Aromatic Hydrocarbons

Abstract Syntheses of large polycyclic aromatic hydrocarbons (PAHs) and graphene nanostructures demand methods that are capable of selectively and efficiently fusing large numbers of aromatic rings, yet such methods remain scarce. Herein, we report a new approach that is based on the quantitative intramolecular reductive cyclization of an oligo(diyne) with a low‐valent zirconocene reagent, which gives a PAH with one or more annulated zirconacyclopentadienes (ZrPAHs). The efficiency of this process is demonstrated by a high‐yielding fivefold intramolecular coupling to form a helical ZrPAH with 16 fused rings (from a precursor with no fused rings). Several other PAH topologies are also reported. Protodemetalation of the ZrPAHs allowed full characterization (including by X‐ray crystallography) of PAHs containing one or more appended dienes with the ortho‐quinodimethane (o‐QDM) structure, which are usually too reactive for isolation and are potentially valuable for the fusion of additional rings by Diels–Alder reactions.

Hydrogen Fuel Production by Transgenic Microalgae

ChemInform Abstract: Modular Chemistry: Secondary Building Units as a Basis for the Design of Highly Porous and Robust Metal—Organic Carboxylate Frameworks

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Low latency via redundancy

Low latency is critical for interactive networked applications. But while we know how to scale systems to increase capacity, reducing latency --- especially the tail of the latency distribution --- can be much more difficult. In this paper, we argue that the use of redundancy is an effective way to convert extra capacity into reduced latency. By initiating redundant operations across diverse resources and using the first result which completes, redundancy improves a system's latency even under exceptional conditions. We study the tradeoff with added system utilization, characterizing the situations in which replicating all tasks reduces mean latency. We then demonstrate empirically that replicating all operations can result in significant mean and tail latency reduction in real-world systems including DNS queries, database servers, and packet forwarding within networks.

The Teenage Brain

In this paper, we discuss the surging hormones of puberty and their influences on adolescent behavior. We describe why these issues represent an interesting and important area of investigation, emphasizing their contributions to a specific set of developmental processes at the heart of the transition from childhood to adolescence. We briefly review the neuroendocrine underpinnings of human puberty. Our review focuses on evidence for behavioral (and neurobehavioral) effects of gonadal hormones and emphasizes the social and affective dimensions of these hormonal effects. More broadly, we consider how these hormonal events contribute to brain-behavior interactions that can bias early adolescent trajectories in both positive and negative directions, and in ways that may begin as small influences but can spiral into large-scale effects over time. These influences also appear to play an important role in functional and structural brain development during adolescence. Finally, we offer some thoughts on directions for future research in these areas.

Molecular catalysis science: Nanoparticle synthesis and instrument development for studies under reaction conditions

25th Anniversary Article: Semiconductor Nanowires – Synthesis, Characterization, and Applications

Semiconductor nanowires (NWs) have been studied extensively for over two decades for their novel electronic, photonic, thermal, electrochemical and mechanical properties. This comprehensive review article summarizes major advances in the synthesis, characterization, and application of these materials in the past decade. Developments in the understanding of the fundamental principles of “bottom‐up” growth mechanisms are presented, with an emphasis on rational control of the morphology, stoichiometry, and crystal structure of the materials. This is followed by a discussion of the application of nanowires in i) electronic, ii) sensor, iii) photonic, iv) thermoelectric, v) photovoltaic, vi) photoelectrochemical, vii) battery, viii) mechanical, and ix) biological applications. Throughout the discussion, a detailed explanation of the unique properties associated with the one‐dimensional nanowire geometry will be presented, and the benefits of these properties for the various applications will be highlighted. The review concludes with a brief perspective on future research directions, and remaining barriers which must be overcome for the successful commercial application of these technologies.