Publications

The role of chloroplast-encoded protein biosynthesis on the rate of D1 protein degradation in Dunaliella salina

CCDC 238423: 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.

Statistical methods on Type Ia supernova luminosity evolution

Much of the cosmological utility thus far extracted from Type Ia supernovae (SNe Ia) relies on the assumption that SN~Ia peak luminosities do not evolve significantly with the age (local or global) of their stellar environments. Two recent studies have provided conflicting results in evaluating the validity of this assumption, with one finding no correlation between Hubble residuals (HR) and stellar environment age, while the other claims a significant correlation. In this Letter we perform an independent reanalysis that rectifies issues with the statistical methods employed by both of the aforementioned studies. Our analysis follows a principled approach that properly accounts for regression dilution and critically (and unlike both prior studies) utilises the Bayesian-model-produced SN environment age estimates (posterior samples) instead of point estimates. Moreover, the posterior is used as an informative prior in the regression. We find the Pearson correlation between the HR and local (global) age to be in excess of $4\sigma$ ($3\sigma$). Assuming there exists a linear relationship between HR and local (global) age, we find a corresponding slope of $-0.035 \pm 0.007\,\mathrm{mag\,Gyr}^{-1}$ ($-0.036 \pm 0.007\,\mathrm{mag\,Gyr}^{-1}$). We encourage further usage of our approach to examine possible cosmological implications of the HR and age correlation.

Synchronization of chaotic and hyperchaotic systems

In this paper, we study the conditions under which chaotic and hyperchaotic systems can be synchronized by impulses sampled from a part of their state variables. By calculating the Lyapunov exponents of variational synchronization error systems, we show that this kind of impulsive synchronization can be applied to almost all hyperchaotic systems. We also study the selective synchronization of chaotic systems. In a selective synchronization scheme, the synchronizing signal is chosen in the time periods when the Lyapunov exponents of variational synchronization error systems are negative. Since only driving signals in the time periods when synchronization error can be reduced is chosen to reduce the synchronization error and those in the time periods when synchronization error can be increased are not used, the selective synchronization scheme can be used to achieve synchronization even in the case when continuous synchronization schemes fail to work.

Theoretical Analysis of the Mechanism for the Oxidative Carbonylation of Toluene to <i>p</i>-Toluic Acid by Rhodium Complexes

Density functional theory has been used to investigate the mechanism and kinetics of the liquid-phase, oxidative carbonylation of toluene to p-toluic acid (C7H8 + CO + 1/2O2 → p-C7H6COOH + H2O) catalyzed by Rh(III) cations. In toluene solution containing trifluoroacetic acid and dissolved CO, Rh(III) is coordinated to three trifluoroacetate (TFA) anions and two CO molecules as Rh(CO)2(TFA)3. The oxidative carbonylation of toluene is initiated by the addition of toluene across one of the Rh−O bonds of Rh(CO)2(TFA)3 to form (C7H7)Rh(CO)2(TFAH)(TFA)2. The latter species undergoes isomerization and CO migration to produce (C7H7CO)Rh(CO)(TFAH)(TFA)2, which then coordinates another molecule of CO. The mixed anhydride of toluic and tirfluoroacetic acid, C7H7C(O)O(O)CCF3 and Rh(CO)3(TFA), are produced by reductive elimination from (C7H7CO)Rh(CO)2(TFAH)(TFA)2. Para-toluic acid is then formed by hydrolysis of C7H7C(O)O(O)CCF3. The proposed reaction mechanism explains many of the observations reported in our previous experimental work (Zakzeski, J. J.; Bell, A. T. J. Mol. Catal. A 2007, 276, 8) and, in particular, the effect of temperature on the ratio of p- to m-toluic acid, the effects of H2O and the partial pressure of CO on the loss of catalyst activity, and the effect of Rh concentration on the formation of a catalytically inactive Rh dimer species.

Catalysis Science &amp; Technology: Catalysis in the USA

Editorial for the themed issue “Catalysis in the USA”.

CCDC 810236: 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.

Nonlinear Device and System Modeling

A comparison of gas-phase and electrochemical hydrogenation of ethylene at platinum surfaces

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA comparison of gas-phase and electrochemical hydrogenation of ethylene at platinum surfacesAndrzej Wieckowski, Stephen D. Rosasco, Ghaleb N. Salaita, Arthur Hubbard, Brian E. Bent, Francisco Zaera, and Gabor A. SomorjaiCite this: J. Am. Chem. Soc. 1985, 107, 21, 5910–5920Publication Date (Print):October 1, 1985Publication History Published online1 May 2002Published inissue 1 October 1985https://pubs.acs.org/doi/10.1021/ja00307a015https://doi.org/10.1021/ja00307a015research-articleACS PublicationsRequest reuse permissionsArticle Views916Altmetric-Citations86LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Mutations of cellulose synthase (CESA1) phosphorylation sites modulate anisotropic cell expansion and bidirectional mobility of cellulose synthase

The CESA1 component of cellulose synthase is phosphorylated at sites clustered in two hypervariable regions of the protein. Mutations of the phosphorylated residues to Ala (A) or Glu (E) alter anisotropic cell expansion and cellulose synthesis in rapidly expanding roots and hypocotyls. Expression of T166E, S686E, or S688E mutants of CESA1 fully rescued the temperature sensitive cesA1-1 allele ( rsw1 ) at a restrictive temperature whereas mutations to A at these positions caused defects in anisotropic cell expansion. However, mutations to E at residues surrounding T166 (i.e., S162, T165, and S167) caused opposite effects. Live-cell imaging of fluorescently labeled CESA showed close correlations between tissue or cell morphology and patterns of bidirectional motility of CESA complexes in the plasma membrane. In the WT, CESA complexes moved at similar velocities in both directions along microtubule tracks. By contrast, the rate of movement of CESA particles was directionally asymmetric in mutant lines that exhibited abnormal tissue or cell expansion, and the asymmetry was removed upon depolymerizing microtubules with oryzalin. This suggests that phosphorylation of CESA differentially affects a polar interaction with microtubules that may regulate the length or quantity of a subset of cellulose microfibrils and that this, in turn, alters microfibril structure in the primary cell wall resulting in or contributing to the observed defect in anisotropic cell expansion.

Engineering Cotton (+)-δ-Cadinene Synthase to an Altered Function: Germacrene D-4-ol Synthase

Computing with front propagation: evolving interfaces and active contour models in continuous-time CNN

In this paper, a linear CNN template class is studied with a symmetric feedback matrix capable of generating trigger-waves, a special type of binary traveling-wave. The qualitative properties of these waves are examined and some simple control strategies are derived based on modifying the bias and feedback terms in a CNN template. It is shown that a properly controlled wave-front can be efficiently used in segmentation, shape and structure detection/recovery tasks. shape discussed that incorporates bias controlled trigger-waves in tracking the active contour of the objects during rigid and non-rigid motion. The object skeleton (structure) is obtained as a composition of stable annihilation lines formed during the collision of trigger wave-fronts. The shortest path problem in a binary labyrinth is also formulated as a special type of skeletonization task and and solved by combined trigger-waves based techniques.

Scaling up flux measurements for the boreal forest using aircraft‐tower combinations

Fluxes of carbon dioxide, water vapor, sensible heat, and momentum obtained over the boreal forest from the Twin Otter aircraft and six tower‐based systems are compared. These measurements were collected as part of the Boreal Ecosystem‐Atmosphere Study (BOREAS) during three intensive field campaigns between May 25 and September 17, 1994. The representativeness of the tower‐based measurements collected during BOREAS is discussed. Even though the net radiation from aircraft‐ and tower‐based systems agreed well, in general, the aircraft tended to observe larger latent heat and smaller sensible heat fluxes than the towers. The CO 2 fluxes from the aircraft were substantially less than from the tower, while the differences were relatively small for the momentum fluxes. The relationships between aircraft and tower‐based flux measurements obtained by making repeated runs past various towers are used to scale up tower‐based fluxes to a 16×16 km 2 area near Prince Albert, Saskatchewan. It is demonstrated that except for a couple of cases primarily due to rapidly changing radiation conditions, this combination of measurements provides regional flux estimates of momentum, CO 2 , and sensible and latent heat similar to those obtained by flying a grid pattern over the area.

On the shape of stress corrosion cracks in sensitized Type 304 SS in Boiling Water Reactor primary coolant piping at 288 °C

Inhibition of leaf respiration by light: implications for eddy-covariance partitioning

Earthquake Response Spectrum Analysis of Intake‐Outlet Towers

A simplified analysis procedure is developed to determine the maximum earthquake forces in intake‐outlet towers directly from the design earthquake spectrum without the need for a response history analysis. All the significant effects of tower‐water interaction and tower‐foundation‐soil, interaction are included in the analysis. It is demonstrated that the hydrodynamic effects can be approximated by added mass functions for outside and inside water. An equivalent SDF system is developed to consider approximately the effects of tower‐foundation‐soil interaction in the fundamental mode response of towers.

Seasonality in aerodynamic resistance across a range of North American ecosystems

Engineering the Electron–Hole Bilayer Tunneling Field-Effect Transistor

The electron-hole (EH) Bilayer Tunneling Field-Effect Transistor promises to eliminate heavy-doping band-tails enabling a smaller subthreshold swing voltage.Nevertheless, the electrostatics of a thin structure must be optimized for gate efficiency.We analyze the tradeoff between gate efficiency versus on-state conductance to find the optimal device design.Once the EH Bilayer is optimized for a given on-state conductance, Si, Ge, and InAs all have similar gate efficiency, around 40-50%.Unlike Si & Ge, only the InAs case allows a manageable work function difference for EH Bilayer Transistor operation.