Sequential Type Research Articles

Gas-phase solvolysis type reactions of SiCl3+ cations

Gas-phase SiCl3+ ions undergo sequential solvolysis type reactions with water, methanol, ammonia, methylamine and propylene. Studies carried out in a Fourier Transform mass spectrometer reveal that these reactions are facile at 10-8 Torr and give rise to substituted chlorosilyl cations. Ab initio and DFT calculations reveal that these reactions proceed by addition of the silyl cation to the oxygen or nitrogen lone pair followed by a 1,3-H migration in the transition state. These transition states are calculated to lie below the energy of the reactants. By comparison, hydrolysis of gaseous CCl3+ is calculated to involve a substantial positive energy barrier.

Acyclovir Susceptibility and Genetic Characteristics of Sequential Herpes Simplex Virus Type 1 Corneal Isolates from Patients with Recurrent Herpetic Keratitis

The incidence and clinical significance of herpes simplex virus type 1 (HSV-1) acyclovir resistance were determined in patients with recurrent herpetic keratitis (RHK). Sequential corneal isolates (n = 39) from 15 immunocompetent patients with RHK were assayed for acyclovir susceptibility and genotyped by analyzing the hypervariable regions of the HSV-1 genes US1 and US12. The thymidine kinase (TK) gene of each isolate was sequenced, and the proportion of acyclovir-resistant viruses within isolates was determined. Uniform acyclovir-resistant or acyclovir-sensitive sequential isolates were identified in 4 and 2 patients, respectively. Notably, the acyclovir susceptibility of sequential isolates changed from acyclovir sensitive to acyclovir resistant (5 patients) or from acyclovir resistant to acyclovir sensitive (3 patients). The acyclovir-resistant phenotype of the isolates correlated with the patient's unresponsiveness to acyclovir therapy. Combined analyses of the TK gene and genotype of sequential isolates showed that acyclovir-sensitive isolates contained multiple acyclovir-resistant variants of the same virus and that an identical acyclovir-resistant HSV-1 strain reappeared in the patient's cornea during RHK episodes. Corneal HSV-1 isolates are mixtures of acyclovir-sensitive and acyclovir-resistant viruses that share the same genotype but have different TK sequences. Recovery of the same acyclovir-resistant virus during consecutive herpetic keratitis episodes suggests that acyclovir-resistant HSV-1 establishes latency and reactivates intermittently to cause acyclovir-refractory RHK.

17.2: Advanced Display Motion Induced Color Distortion and Crosstalk Analysis Methods

AbstractMotion artifact of Display devices has a huge interest from industries and users recently. Among those artifacts, color break up (CBU) and Dynamic false contour are the main degrading characteristic in field sequential type displays and Plasma Displays. Also, motion blur has been researched intensively recently, but there is a critical motion induced artifact due to phosphor or LC unwanted performance. This visual phenomenon is similar to normal crosstalk artifact, so it is named as motion crosstalk. Unfortunately, there are no objective measurement methods for those two motion‐induced artifacts. Here we introduce advanced analysis methods for two different kinds of motion artifacts.

Imposex and butyltin body burden in Nassarius nitidus (Jeffreys, 1867), in coastal waters within the Basque Country (northern Spain)

Levels of imposex (superimposition of male characters, upon females) and the presence of sterile females are assessed in the gastropod Nassarius nitidus (Jeffreys, 1867), at 22 locations in the Basque Country (northern Spain). At 18 of these localities, butyltin bioaccumulation (tributyltin (TBT); dibutyltin; monobutyltin) was analysed using isotope dilution and GC–ICP-MS. Higher imposex levels and TBT body burden were found in confined harbours, with a large vessel traffic or the presence of a fishing fleet or a shipyard. For the first time, four apparently sequential types of aborted capsules are described in this species. Another novelty is the interspecific comparison between imposex intensities in sympatrically living populations of N. nitidus and N. reticulatus. This showed that sensitivity to TBT pollution of both species is relatively similar (in terms of Relative Penis Length Index). Since N. nitidus has a restricted habitat distribution due to its low presence in wave-exposed habitats, its complementary use with other species is recommended for its use in TBT monitoring programmes.

A new dynamical model of brainstorming: Linear, nonlinear, continuous (simultaneous) and impulsive (sequential) cases

In this paper, we extended the linear dynamical model of [Brown, V., Paulus, P. B. (1996). A simple dynamic model of social factors in group brainstorming. Small Group Research, 27, 91–114] on two accounts. First, we modelled the sequential type brainstorming using impulsive differential equations by treating each category as an impulse and tested its validity in the two experiments that investigated and demonstrated the beneficial effects of sequential priming and memory in individual brainstorming. Finally, we considered the nonlinear case of brainstorming in writing or brainwriting where dyads exchanged their ideas in a written format and that eliminated negative factors occurring in oral brainstorming (e.g., evaluation apprehension, free-riding, production blocking) and enhanced the upward performance matching, and conducted the second experiment in order to test its validity in this paradigm with the effects of sequential priming and memory. Comparisons showed good agreement between results of experiments and those of the mathematical model.

CaMKII Phosphorylates Phospholamban via an Ordered Sequential Kinetic Mechanism

Many of the cellular responses to Ca++ signal are modulated by a family of multifunctional Ca++/calmodulin dependent protein kinases (CaMKs): CaMKI, CaMKII and CaMKIV. CaMKII has an autoregulatory domain that restricts enzyme activity in the absence of Ca++/CaM. Ca++/CaM binding alone produce maximal activity of CaMKII, whereas CaMKI and CaMKIV have an activation loop that requires phosphorylation by an upstream CaMK kinase for maximal activity. In addition to its role in memory and other neuronal functions, CaMKII appears to mediate many of the pathologic changes that occur during cardiac hypertrophy and heart failure. In order to further understand the role of CaMKII, we investigated the kinetic mechanism of CaMKII (IIα, IIβ, IIδ, IIγ) in comparison with those of CaMKI and CaMKIV by analyzing their steady state kinetics using phospholamban as a phosphoacceptor. The results indicated that (a) CaMK family's reaction mechanisms were of the sequential type in which all substrates must bind to enzyme before any product is released; (b) While CaMKIIs catalyzed Ordered Bi Bi reaction where phospholamban was the first substrate to bind and ADP was the last product to be released, CaMKI and CaMKIV exhibited random sequential mechanism where either phospholamban and ATP can bind to the free enzyme and (c) Constant α (ratio of apparent dissociation constants for binding peptide in the presence and absence of the second ligand) of all isozymes for ATP and peptide was higher than 1 indicating that the binding of phospholamban to CaMK decreased its affinities toward ATP. Our results suggested a unique kinetic mechanism for CaMKIIs in which peptide substrate binding may be an initiating factor for the catalysis and may play a role in the regulation of the enzyme activity in cells.

Characterization of putative tryptophan monooxygenase from Ralstonia solanasearum

The amino-acid sequence of a putative tryptophan monooxygenase (PTMO) from Ralstonia solanacearum is homologous with that of proenzyme (proPAO) of l-Phe oxidase (deaminating and decarboxylating) (PAO) from Pseudomonas sp. P-501 in their overall sequences. PTMO was expressed in E. coli and purified, but had no catalytic activity to oxidize l-Phe. By treating PTMO with various proteases, the Pronase-treated PTMO (PTMOp) showed a relatively high activity to oxidize l-Phe, l-Trp, l-Tyr and l-Met. Studies on the stoichiometry of the reaction showed that l-Phe and l-Tyr were mostly oxygenated, that l-Met was mostly oxidized, and both oxygenation and oxidation of l-Trp was observed. Initial velocity patterns were a ping-pong type with l-Phe and l-Tyr, and a sequential type with l-Trp and l-Met as substrate. The spectrum of enzymes with sufficient amounts of these substrates to reduce the enzyme showed a long wavelength species (purple complex) with l-Phe, but not with l-Tyr, l-Trp and l-Met. These results lead to the conclusion that PTMO and PTMOp belong to proPAO and PAO, respectively.

ChemInform Abstract: Sequential Norrish Type II Photoelimination and Intramolecular Aldol Cyclization of 1,2‐Diketones in Carbohydrate Systems: Stereoselective Synthesis of Cyclopentitols.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 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.

Iron(III) Salt‐Catalyzed Nazarov Cyclization/Michael Addition of Pyrrole Derivatives

AbstractThe Nazarov cyclization of two types of pyrrole derivatives was effectively catalyzed by 5 mol% alumina‐supported iron(III) perchlorate [Fe(ClO4)3⋅Al2O3 ] which provided the desired cyclization with high trans selectivity in good to excellent yield. The cyclized product was next reacted with a vinyl ketone in the presence of the same iron salt to afford the corresponding Michael product. A sequential type Nazarov/Michael reaction of pyrrole derivatives has also been accomplished; the synthetic route to 4,5‐dihydrocyclopenta[b]pyrrol‐6(1 H)‐one derivative 5 or 5,6‐dihydrocyclopenta[b]pyrrol‐4(1 H)‐one derivative 6 has thus been established using a very economical iron catalyst.

Steps in the design, development and formative evaluation of obesity prevention-related behavior change trials.

Obesity prevention interventions through dietary and physical activity change have generally not been effective. Limitations on possible program effectiveness are herein identified at every step in the mediating variable model, a generic conceptual framework for understanding how interventions may promote behavior change. To minimize these problems, and thereby enhance likely intervention effectiveness, four sequential types of formative studies are proposed: targeted behavior validation, targeted mediator validation, intervention procedure validation, and pilot feasibility intervention. Implementing these studies would establish the relationships at each step in the mediating variable model, thereby maximizing the likelihood that an intervention would work and its effects would be detected. Building consensus among researchers, funding agencies, and journal editors on distinct intervention development studies should avoid identified limitations and move the field forward.

Neutralization Patterns and Evolution of Sequential HIV Type 1 Envelope Sequences in HIV Type 1 Subtype B-Infected Drug-Naive Individuals

To design a vaccine that will remain potent against HIV-1, the immunogenic regions in the viral envelope that tend to change as well as those that remain constant over time must be identified. To determine the neutralization profiles of sequential viruses over time and study whether neutralization patterns correlate with sequence evolution, 12 broadly neutralizing plasmas from HIV-1 subtype B-infected individuals were tested for their ability to neutralize sequential primary HIV-1 subtype B viruses from four individuals. Three patterns of neutralization were observed, including a loss of neutralization sensitivity by viruses over time, an increase in neutralization sensitivity by sequential viruses, or a similarity in the sensitivity of sequential viruses to neutralization. Seven to 11 gp160 clones from each sequential virus sample were sequenced and analyzed to identify mutational patterns. Analysis of the envelope sequences of the sequential viruses revealed changes characteristic of the neutralization patterns. Viruses that evolved to become resistant to neutralizing antibodies also evolved with diverse sequences, with most of the changes being due to nonsynonymous mutations occurring in the V1/V2, as well as in the constant regions (C2, C3, C4), the most changes occurring in the C3. Viruses from the patient that evolved to become more sensitive to neutralization exhibited less sequence diversity with fewer nonsynonymous changes that occurred mainly in the V1/V2 region. The V3 region remained constant over time for all the viruses tested. This study demonstrates that as viruses evolve in their host, they either become sensitive or resistant to neutralization by antibodies in heterologous plasma and mutations in different envelope regions account for these changes in their neutralization profiles.

Sequential Norrish Type II Photoelimination and Intramolecular Aldol Cyclization of 1,2‐Diketones in Carbohydrate Systems: Stereoselective Synthesis of Cyclopentitols

Opened and closed: Visible-light photostimulation of 2,3-diuloses I triggers an unprecedented sequential rearrangement: A Norrish type II photoelimination to give an isolable acyclic photoenol intermediate II is followed by an intramolecular enolexo aldolization. The contraction of the pyranose ring in this process leads to a new type of cyclopentitol derivative III. R=acyl, alkyl, silyl group.

Sequential Norrish Type II Photoelimination and Intramolecular Aldol Cyclization of 1,2‐Diketones in Carbohydrate Systems: Stereoselective Synthesis of Cyclopentitols

Öffnen und wieder schließen: Die Photoanregung von 2,3-Diulosen I mit sichtbarem Licht löst eine ungewöhnliche sequenzielle Umlagerung aus: eine Norrish-II-Photoeliminierung unter Bildung der isolierbaren acyclischen Photoenol-Zwischenstufe II, an die sich eine intramolekulare Enolexoaldolisierung anschließt. Die Kontraktion des Pyranoserings führt zu neuartigen Cyclopentitolen III. R=Acyl, Alkyl, Silyl. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. 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.

Properties of equation reformulation of the Karush–Kuhn–Tucker condition for nonlinear second order cone optimization problems

We give an equation reformulation of the Karush–Kuhn–Tucker (KKT) condition for the second order cone optimization problem. The equation is strongly semismooth and its Clarke subdifferential at the KKT point is proved to be nonsingular under the constraint nondegeneracy condition and a strong second order sufficient optimality condition. This property is used in an implicit function theorem of semismooth functions to analyze the convergence properties of a local sequential quadratic programming type (for short, SQP-type) method by Kato and Fukushima (Optim Lett 1:129–144, 2007). Moreover, we prove that, a local solution x* to the second order cone optimization problem is a strict minimizer of the Han penalty merit function when the constraint nondegeneracy condition and the strong second order optimality condition are satisfied at x*.

Spatial-behavioral types for concurrency and resource control in distributed systems

We develop a notion of spatial-behavioral typing suitable to discipline concurrent interactions and resource usage in distributed object systems. Our type structure reflects a resource sensitive model, where a parallel composition type operator expresses resource independence, a sequential composition type operator expresses resource synchronization, and a type modality expresses resource ownership. We model the intended computational systems using a concurrent object calculus. Soundness of our type system is established using a logical relations technique, building on a interpretation of types as properties expressible in a spatial logic.

Sequential input selection algorithm for long-term prediction of time series

In time series prediction, making accurate predictions is often the primary goal. At the same time, interpretability of the models would be desirable. For the latter goal, we have devised a sequential input selection algorithm (SISAL) to choose a parsimonious, or sparse, set of input variables. Our proposed algorithm is a sequential backward selection type algorithm based on a cross-validation resampling procedure. Our strategy is to use a filter approach in the prediction: first we select a sparse set of inputs using linear models and then the selected inputs are used in the nonlinear prediction conducted with multilayer-perceptron networks. Furthermore, we perform a sensitivity analysis by quantifying the importance of the individual input variables in the nonlinear models using a method based on partial derivatives. Experiments are done with the Santa Fe laser data set that exhibits very nonlinear behavior and a data set in a problem of electricity load prediction. The results in the prediction problems of varying difficulty highlight the range of applicability of our proposed algorithm. In summary, our SISAL yields accurate and parsimonious prediction models giving insight to the original problem.

On local convergence of sequential quadratically-constrained quadratic-programming type methods, with an extension to variational problems

We consider the class of quadratically-constrained quadratic-programming methods in the framework extended from optimization to more general variational problems. Previously, in the optimization case, Anitescu (SIAM J. Optim. 12, 949–978, 2002) showed superlinear convergence of the primal sequence under the Mangasarian-Fromovitz constraint qualification and the quadratic growth condition. Quadratic convergence of the primal-dual sequence was established by Fukushima, Luo and Tseng (SIAM J. Optim. 13, 1098–1119, 2003) under the assumption of convexity, the Slater constraint qualification, and a strong second-order sufficient condition. We obtain a new local convergence result, which complements the above (it is neither stronger nor weaker): we prove primal-dual quadratic convergence under the linear independence constraint qualification, strict complementarity, and a second-order sufficiency condition. Additionally, our results apply to variational problems beyond the optimization case. Finally, we provide a necessary and sufficient condition for superlinear convergence of the primal sequence under a Dennis-Moré type condition.

Efficiency analyses of solid oxide fuel cell power plant systems

In this paper, the effects of fuel utilization, air-to-fuel ratio (A/F) and pre-reforming rate on the plant efficiency, including heat and electric efficiencies, of sequential-type and fully recuperative-type of solid oxide fuel cell (SOFC) power plant are studied with the GCTool software developed by American Argonne National Laboratory (ANL). Methane is chosen as fuel, air as oxidant, and the pressure drop due to stream transported in the duct and components is considered in both types of power plant systems. A full analysis of the state at each node of the system is conducted. The results reveal that the A/F factor is the most important factor on system efficiency, and the pre-reforming rate of fuel is insignificant to the efficiency, but it can be used as an auxiliary tuner for the operating temperature of the solid oxide fuel cells in addition to A/F value. Under the same settings, overall plant efficiency is higher in the sequential type than in the fully recuperative type of SOFC power plants. On the other hand, for electric efficiency, the opposite trend is observed.

Asymptotic normality associated with generalized occupancy problems

We consider a scheme of independent allocation of particles of s types into an infinite number of cells. The object of interest here are the statistics that are the sum of functions of the frequencies of the cells. The asymptotic normality of these statistics is proved under weaker conditions than those known. This result is then applied in the construction of a goodness of fit test of sequential type to verify a hypothesis about discrete distributions.

On smeared and micromechanical approaches to modeling martensitic transformations in SMA

This paper explores a link between a recently proposed macroscopic “smeared” approach and a microscopic/mesoscopic approach of sequential laminate type to model martensitic transformations. In addition, a numerical simulation of the stress-induced martensitic transformation in a single crystal has been performed upon simplification to small deformations. One significant observation in the results of such a simulation is the counter-intuitive change of preferred martensitic plate even under proportional loading conditions. It remains to be seen if it is an artifact of the procedure adopted or the actual shift of active martensitic plate system. A further step toward modeling polycrystal behavior using homogenization with simple bounds has been attempted. Hysteresis results show that there is no clear demarcation of critical stress at which the transformation occurs. This may be critical to the functional fatigue behavior of shape memory materials.