Three-step Sequential Process Research Articles

Drug and Natural Health Product Data Collection and Curation in the Canadian Longitudinal Study on Aging.

This study aimed to develop an efficient data collection and curation process for all drugs and natural health products (NHPs) used by participants to the Canadian Longitudinal Study on Aging (CLSA). The three-step sequential process consisted of (a) mapping drug inputs collected through the CLSA to the Health Canada Drug Product Database (DPD), (b) algorithm recoding of unmapped drug and NHP inputs, and (c) manual recoding of unmapped drug and NHP inputs. Among the 30,097 CLSA comprehensive cohort participants, 26,000 (86.4%) were using a drug or an NHP with a mean of 5.3 (SD 3.8) inputs per participant user for a total of 137,366 inputs. Of those inputs, 70,177 (51.1%) were mapped to the Health Canada DPD, 20,729 (15.1%) were recoded by algorithms, and 44,108 (32.1%) were manually recoded. The Direct algorithm correctly classified 99.4 per cent of drug inputs and 99.5 per cent of NHP inputs. We developed an efficient three-step process for drug and NHP data collection and curation for use in a longitudinal cohort.

Rydberg state excitation in molecules manipulated by bicircular two-color laser pulses

Multiphoton resonant excitation and frustrated tunneling ionization, manifesting the photonic and optical nature of the driving light via direct excitation and electron recapture, respectively, are complementary mechanisms to access Rydberg state excitation (RSE) of atoms and molecules in an intense laser field. However, clear identification and manipulation of their individual contributions in the light-induced RSE process remain experimentally challenging. Here, we bridge this gap by exploring the dissociative and nondissociative RSE of H2 molecules using bicircular two-color laser pulses. Depending on the relative field strength and polarization helicity of the two colors, the RSE probability can be boosted by more than one order of magnitude by exploiting the laser waveform-dependent field effect. The role of the photon effect is readily strengthened with increasing relative strength of the second-harmonic field of the two colors regardless of the polarization helicity. As compared to the nondissociative RSE forming H2 * , the field effect in producing the dissociative RSE channel of ( H + , H * ) is moderately suppressed, which is primarily accessed via a three-step sequential process separated by molecular bond stretching. Our work paves the way toward a comprehensive understanding of the interplay of the underlying field and photon effects in the strong-field RSE process, as well as facilitating the generation of Rydberg states optimized with tailored characteristics.

Ethylene glycol assisted self-template conversion approach to synthesize hollow NiS microspheres for a high performance all-solid-state supercapacitor

Hollow NiS microspheres were synthesized via an ethylene glycol assisted three-step sequential process, which displayed excellent performance in an all solid state supercapacitor.

Optimal inspection and replacement strategy for 145 kV gas-insulated switchgear

We deal with an optimization problem of planning a maintenance strategy for 145 kV gas-insulated switchgear and apply reliability-centered maintenance approach to find an efficient and effective strategy. In a three-step sequential process, we use failure mode effects and criticality analysis to define the critical failure modes that cause the major failures of 145 kV gas-insulated switchgear, select the maintenance significant items to remove the major failure modes, and finally apply logic tree analysis to assign the appropriate maintenance task to each critical failure modes in the system. We then compare the assigned maintenance tasks with existing tasks in the installation, operation, and maintenance manuals developed in the system design and development phase. The assigned maintenance tasks in this study are compared with those in the system design and development phase by simulation, and a simple heuristic method is proposed to find optimal solutions.

Facile and Cost-Effective Approach for Copper Recovery from Waste Printed Circuit Boards via a Sequential Mechanochemical/Leaching/Recrystallization Process.

The recovery of copper (Cu0) from waste printed circuit boards (WPCBs) is a great challenge as a result of its heterogeneous structural properties, with a mixture of metals, epoxy resin, and fiberglass. In this study, a three-step sequential process, including mechanochemical processing, water leaching, and recrystallization, for Cu0 recovery from WPCB powder is reported. Potassium persulfate (K2S2O8), instead of acid/alkali reagents, was employed as the sole reagent in the cupric sulfate (CuSO4) regeneration process. Complete oxidation of Cu0 in the WPCBs to copper oxide (CuO) and CuSO4 was first achieved during mechanochemical processing with K2S2O8 as the solid oxidant, and the K2S2O8 was simultaneously converted to sulfate compounds [K3H(SO4)2] via a solid-solid reaction with epoxy resin (C nH mO y) as the hydrogen donator under mechanical force. The rapid leaching of Cu species in the forms of CuO and CuSO4 was therefore easily realized with pure water as a nontoxic leaching reagent. The kinetics of the leaching process of Cu species was confirmed to follow the shrinking nucleus model controlled by solid-film diffusion. Finally, CuSO4·5H2O was successfully separated by cooling crystallization of the hot saturated solution of sulfate salt [K2Cu(SO4)2·6H2O]. An efficient conversion of Cu0 to CuSO4·5H2O product, for WPCB recycling, was therefore established.

Large-scale synthesis of lead telluride (PbTe) nanotube-based nanocomposites with tunable morphology, crystallinity and thermoelectric properties

A few millimeter-long lead telluride (PbTe) hollow nanofibers with thermoelectric properties was synthesized for the first time with high through manner via three-step sequential process of electrospinning, electrodeposition and cationic exchange reaction. As-synthesized electrospun Ag nanofibers with ultra-long aspect ratio of 10,000 were Te electrodeposited to obtain silver telluride nanotubes and underwent cationic exchange reaction in Pb(NO3)2 solution to obtain polycrystalline PbTe nanotubes with average diameter of 100 nm with 20 nm of wall thickness. Variation of the Ag-to-Pb ratio in the AgxTey-PbTe nanocomposites during the cationic exchange reaction enabled to control the thermoelectric properties of resulting 1D hollow nanofibers. The diameter of Ag nanofiber is the key factor to determine the final dimension of the PbTe nanotubes in the topotactic transformation and the content of Ag ion leads to the enhancement of thermoelectric properties in the AgxTey-PbTe nanocomposites. The synthesized 1D nanocomposite mats showed the highest value of Seebeck coefficient of 433 μV/K (at 300 K) when the remained Ag content was 30%, while the power factor reached highest to 0.567 μW/mK2 for the pure PbTe nanotubes. The enhancement of thermoelectric properties and the composite crystallinity are elucidated with relation to Ag contents in the resulting 1D nanocomposites.

Layer-by-layer etching of LaAlSiOx

Layer-by-layer etching of LaAlSiOx using surface modification and selective removal steps was investigated. Selective removal of the LaAlSiOx layer modified by H2 plasma treatment was achieved by bias-power-adjusted C4F8/Ar plasma treatment. Self-limiting etching of LaAlSiOx with respect to the C4F8/Ar plasma step time was realized by initializing the chamber condition using O2 plasma. It was possible to control the saturation etching depth by changing the ion energy of the H2 plasma treatment. The repeatability of the self-limiting etching was confirmed, and the etching depth per cycle was about 0.6 nm. Layer-by-layer etching of LaAlSiOx was thus successfully realized using a three-step sequential process employing H2, C4F8/Ar and O2 plasmas.

Self-regulation of eating and physical activity is lower in obese female college students as compared to their normal weight counterparts.

Obesity is characterized, among other features, by overeating, reduced physical activity and an abnormal accumulation of body fat. These features are thought to result, at least in part, from the individual's inability to self-regulate their eating and physical activity behaviors (E&PaB). Self-regulation of the E&PaB is a three-step sequential process: self-observation, self-evaluation and self-reaction. However, it is yet unclear whether deficient self-regulation of E&PaB could predispose, facilitate and/or consolidate obesity. Unraveling this issue is fundamental in order to more precisely define the role of self-regulation of E&PaB in the management of obesity. This research was focused on the question of whether or not self-regulation of E&PaB is related to obesity in female undergraduate students. This population segment seems especially vulnerable to developing obesity since they undergo a significant shift of their E&PaB upon their university enrollment. To address this question, a cross-sectional study with 108 female undergraduate students with normal weight (n=80) or obesity (n=28) was performed, in which self-regulation of eating habits and physical activity was measured by two validated scales and a personal data questionnaire. Female undergraduate students displaying lower E&PaB self-reactions were consistently overweight or obese. In addition, a multivariate analysis identified high levels of self-reaction towards eating habits related to a minor presence of overweight issues or obesity. Self-regulation should be an essential component in the strategies for obesity prevention as an integral approach that must include orientation about healthy eating and physical activity behaviors. In addition, further studies on the effect of self-regulation in the treatment of the obesity are needed.

Co@Co3 O4 @PPD Core@bishell Nanoparticle-Based Composite as an Efficient Electrocatalyst for Oxygen Reduction Reaction.

Durable electrocatalysts with high catalytic activity toward oxygen reduction reaction (ORR) are crucial to high-performance primary zinc-air batteries (ZnABs) and direct methanol fuel cells (DMFCs). An efficient composite electrocatalyst, Co@Co3 O4 core@shell nanoparticles (NPs) embedded in pyrolyzed polydopamine (PPD) is reported, i.e., in Co@Co3 O4 @PPD core@bishell structure, obtained via a three-step sequential process involving hydrothermal synthesis, high temperature calcination under nitrogen atmosphere, and gentle heating in air. With Co@Co3 O4 NPs encapsulated by ultrathin highly graphitized N-doped carbon, the catalyst exhibits excellent stability in aqueous alkaline solution over extended period and good tolerance to methanol crossover effect. The integration of N-doped graphitic carbon outer shell and ultrathin nanocrystalline Co3 O4 inner shell enable high ORR activity of the core@bishell NPs, as evidenced by ZnABs using catalyst of Co@Co3 O4 @PPD in air-cathode which delivers a stable voltage profile over 40 h at a discharge current density of as high as 20 mA cm(-2) .

Diversification of four human HOX gene clusters by step-wise evolution rather than ancient whole-genome duplications.

HOX genes encode transcriptional factors that play a pivotal role in specifying regional identity in nearly every bilateral animal. The birth of HOX gene cluster and its subsequent evolution, either in regulation or function, underlie the evolution of many bilaterian features and hence to the evolutionary radiation of this group. Despite of this importance, evolution of HOX cluster in vertebrates remains largely obscure because the phylogenetic history of these genes is poorly resolved. This has led to the controversy about whether four HOX clusters in human originated through two rounds (2R) of whole-genome duplications or instead evolved by small-scale events early in vertebrate evolution. Recently, the large-scale phylogenetic analysis of triplicate and quadruplicate paralogous regions residing on human HOX-bearing chromosomes provided an unprecedented insight into events that shaped vertebrate genome early in their history. Based on these data and comparative genomic analysis of fruit fly, red floor beetle, and human, this study infers the genic content of minimal HOX locus in the Urbilaterian and reconstructs its duplication history. It appears that four HOX clusters of humans are not remnants of polyploidy events in vertebrate ancestry. Rather, current evidence suggests that one-to-four transition in HOX cluster number occurred by three-step sequential process involving regional duplication events. Therefore, it is concluded that the evolutionary origin of vertebrate novelties, including the complexity of their body, is the consequence of small-scale genetic changes at widely different times over their history.

Diastereoselective Synthesis of 1,3-syn-Oxazines via a Tandem Hemiaminalization and Tsuji-Trost Reaction

A novel domino sequence for the rapid assembly of 1,3-syn-substituted oxazines is reported. Mechanistically, the one-pot procedure is based on a three-step sequential process involving a hemiaminalization and Tsuji–Trost reaction. The process generates up to two new stereogenic centers in a concise and convergent fashion from simple and readily available starting materials.

Interactive characterization of granulated materials

This paper illustrates an interactive approach to digital characterization of granulated materials, based on mathematical morphology, digital topology and non-linear differential equations. The digital characterization is achieved using a three-step sequential process, namely: denoising, interactive segmentation and quantification, with emphasis in the interactive segmentation step, since it has significant impact on the characterization results. Denoising is used to extract foreground and background markers. Image segmentation results from an anisotropic region-growing and merging process based on immersion simulation. Region-growing evolves as a fully automated process, initiated at local image minima, while merging requires manual insertion of one single marker per region-of-interest. Non-significant regions are merged according to a hierarchy established by a set of markers and merging rules, which represent a robust solution to the over-segmentation problem inherent to immersion simulation algorithms. The sensitivity of the segmentation algorithm to local intensity variations allows the detection of the edges with high accuracy. Quantification is achieved using a suitable stereometric method, which computes the three-dimensional size distribution from the two-dimensional size distribution observed on the image. It is shown that this interactive approach represents a viable solution to digital characterization of granulated materials.

Multiple-step kinetic mechanism of DNA-independent ATP binding and hydrolysis by Escherichia coli replicative helicase DnaB protein: quantitative analysis using the rapid quench-flow method

The kinetic mechanism of DNA-independent binding and hydrolysis of ATP by the E. coli replicative helicase DnaB protein has been quantitatively examined using the rapid quench-flow technique. Single-turnover studies of ATP hydrolysis, in a non-interacting active site of the helicase, indicate that bimolecular association of ATP with the site is followed by the reversible hydrolysis of nucleotide triphosphate and subsequent conformational transition of the enzyme-product complex. The simplest mechanism, which describes the data, is a three-step sequential process defined by:Helicase+ATP⇌k−1k1(H−ATP)⇌k−2k2(H−ADP·Pi)⇌k−3k3(H−ADP·Pi)∗ The sequential character of the mechanism excludes conformational transitions of the DnaB helicase prior to ATP binding. Analysis of relaxation times and amplitudes of the reaction allowed us to estimate all rate and equilibrium constants of partial steps of the proposed mechanism. The intrinsic binding constant for the formation of the (H-ATP) complex is KATP = (1.3 ± 0.5) × 105 M−1. The analysis of the data indicates that a part of the ATP binding energy originates from induced structural changes of the DnaB protein-ATP complex prior to ATP hydrolysis. The equilibrium constant of the chemical interconversion is KH = k2/k−2 ∼ 2 while the subsequent conformational transition is characterized by K3 = k3/k−3 ∼ 30. The low value of KH and the presence of the subsequent energetically favorable conformational step(s) strongly suggest that free energy is released from the enzyme-product complex in the conformational transitions following the chemical step and before the product release.The combined application of single and multiple-turnover approaches show that all six nucleotide-binding sites of the DnaB hexamer are active ATPase sites. Binding of ATP to the DnaB hexamer is characterized by the negative cooperativity parameter σ = 0.25(±0.1). The negative cooperative interactions predominantly affect the ground state of the enzyme-ATP complex. The significance of these results for the mechanism of the free energy transduction of the DnaB helicase is discussed.

Friction force microscopy study of diamond films modified by a glow discharge treatment

Abstract A glow discharge treatment technique has been developed which enables control of the surface roughness and morphology of diamond films for applications in optical and electrical components. A conventional hot filament chemical vapour deposition (CVD) system was used to deposit the diamond films onto silicon substrates via a three-step sequential process: (i) deposition under normal conditions; (ii) exposure to either a pure hydrogen plasma or 3% methane in an excess of hydrogen using DC-bias; and (iii) diamond deposition for a further 2 h under standard conditions. The frictional characteristics and roughness of the film surfaces were investigated by atomic force microscopy (AFM) and the morphology and the growth rates determined from scanning electron microscope images. Lateral force microscopy (LFM) has revealed significant differences in frictional behaviour between the high quality diamond films and those modified by a glow discharge treatment. Friction forces on the diamond films were very low, with coefficients ∼0.01 against silicon nitride probe tips in air. However, friction forces and coefficients were significantly greater on the DC-biased films indicating the presence of a mechanically weaker material such as an amorphous carbon layer. A combination of growth rate and frictional data indicated that the exposure to the H 2 plasma etched the diamond surface whereas exposure to CH 4 /H 2 plasma resulted in film growth. Re-Nucleation of diamond was possible (stage iii) after exposure to either plasma treatment. The resultant friction forces on these films were as low as on the standard diamond film.

Continuous upgrading of a plastics pyrolysis liquid to an environmentally favorable gasoline range product

A residual liquid from plastics pyrolysis was upgraded to a gasoline range product using a three-step sequential process consisting of hydrotreating, hydrocracking and distillation. Two sequences of treatments were performed in nominal 100-h continuous runs, with overall gasoline range product yields of 46% and 53% based on the total liquid feed. The gasoline range product produced from upgrading the residual plastics pyrolysis liquid, when compared to a mid-grade commercial gasoline, was characterized by higher paraffins, lower aromatics, olefins and nitrogen, with comparable research octane number. These properties, evidenced by the gasoline fraction produced from the pyrolysis liquid, indicate a potentially more favorable gasoline from an environmental viewpoint.

The chemical nature of the carbon precursor in bias-enhanced nucleation of CVD diamond

Abstract The effect of sample biasing on CVD diamond nucleation on Si(100) substrates by the MW method has been previously addressed; however, the question as to the changes a silicon substrate undergoes under bias treatment is still open. In the present work we address this question by investigating the chemical reactivity of the material deposited during substrate bias. The different etching behavior in a hydrogen plasma of the possible precursor layer formed on silicon during the bias treatment is utilized. Silicon substrates were subjected to a three-step sequential process: (i) bias pretreatment, (ii) exposure to a pure hydrogen plasma and (iii) deposition under normal conditions. The characterization of the deposited films following each of these stages was carried out by Raman, AES and AFM. It was found that the carbon precursor to diamond growth, formed during the biasing stage, is stable under the etching process. This result suggests that the deposited material at this stage does not consist solely of a carbon network etchable by the hydrogen plasma, such as amorphous carbon (sp2 or sp3 bonded) and microcrystalline graphite or silicon carbide. It may therefore, be suggested that the precursor to diamond growth deposited during the bias process consists of non-etchable nanocrystallite diamond particles.