Non-selective Process Research Articles

Metabolic adaption of cancer cells toward autophagy: Is there a role for ER-phagy?

Autophagy is an evolutionary conserved catabolic pathway that uses a unique double-membrane vesicle, called autophagosome, to sequester cytosolic components, deliver them to lysosomes and recycle amino-acids. Essentially, autophagy acts as a cellular cleaning system that maintains metabolic balance under basal conditions and helps to ensure nutrient viability under stress conditions. It is also an important quality control mechanism that removes misfolded or aggregated proteins and mediates the turnover of damaged and obsolete organelles. In this regard, the idea that autophagy is a non-selective bulk process is outdated. It is now widely accepted that forms of selective autophagy are responsible for metabolic rewiring in response to cellular demand. Given its importance, autophagy plays an essential role during tumorigenesis as it sustains malignant cellular growth by acting as a coping-mechanisms for intracellular and environmental stress that occurs during malignant transformation. Cancer development is accompanied by the formation of a peculiar tumor microenvironment that is mainly characterized by hypoxia (oxygen < 2%) and low nutrient availability. Such conditions challenge cancer cells that must adapt their metabolism to survive. Here we review the regulation of autophagy and selective autophagy by hypoxia and the crosstalk with other stress response mechanisms, such as UPR. Finally, we discuss the emerging role of ER-phagy in sustaining cellular remodeling and quality control during stress conditions that drive tumorigenesis.

High Selectivity, Low Damage ICP Etching of p-GaN over AlGaN for Normally-off p-GaN HEMTs Application.

A systematic study of the selective etching of p-GaN over AlGaN was carried out using a BCl3/SF6 inductively coupled plasma (ICP) process. Compared to similar chemistry, a record high etch selectivity of 41:1 with a p-GaN etch rate of 3.4 nm/min was realized by optimizing the SF6 concentration, chamber pressure, ICP and bias power. The surface morphology after p-GaN etching was characterized by AFM for both selective and nonselective processes, showing the exposed AlGaN surface RMS values of 0.43 nm and 0.99 nm, respectively. MIS-capacitor devices fabricated on the AlGaN surface with ALD-Al2O3 as the gate dielectric after p-GaN etch showed the significant benefit of BCl3/SF6 selective etch process.

Ferrate(VI) pre-treatment and subsequent electrochemical advanced oxidation processes: Recycling iron for enhancing oxidation of organic pollutants

Pharmaceutical residues as emerging pollutants constitute an issue of growing concern owing to their continuous accumulation in the aquatic environment. The removal of such compounds from water requires the development of efficient technologies as well as a better understanding of degradation mechanisms since expensive treatment strategies are necessary for the total mineralization of these compounds. This paper focuses on the potential of combining ferrate (FeVI) oxidation with either anodic oxidation (AO) or electro-Fenton (EF) processes, in comparison with standalone processes, for the degradation of a model pharmaceutical compound (paracetamol). Particularly, recycling iron from FeVI oxidation as catalyst for the EF process is reported for the first time. A particular emphasis is done on identification/quantification of by-products, comparison of degradation pathways and evolution of acute toxicity during the treatment in order to provide novel insights on the possibility to use selective or non-selective oxidation processes for the removal of emerging organic pollutants in a cost-effective way. The most promising treatment strategy appeared to be the use of ferrate as a pre-oxidation step and further as iron source for the electro-Fenton process. Fast degradation kinetics, low aromatic by-products formation and strong decrease of the acute toxicity of the treated solutions highlighted a promising potential of this combined process for transformation of the persistent organic pollutant into harmless/biodegradable by-products.

Influential mechanism of water occurrence states of waste-activated sludge: Potential linkage between water-holding capacity and molecular compositions of EPS

The water occurrence states in waste-activated sludge (WAS) are crucial to its dewaterability and significantly influenced by the water-retaining capacity of extracellular polymeric substances (EPS) matrix. Accordingly, the non-selective •OH-oxidation processes were widely reported for the sludge dewaterability improvement, just because it can non-selectively destruct complex structure units of EPS, no matter these structure units are crucial to EPS water-holding capacity or not. But these non-selective processes may also require the large consumption of oxidant chemicals, which limits their wide application. This study specifically focused on the •OH-induced variation in molecular compositions of EPS and the corresponding effects on water occurrence states of WAS, which is expected to lay a foundation for optimizing the efficiency of oxidation-based sludge conditioning. Especially, through a novel method based on the equilibrium dialysis with alkaline titration, the typical hydrophilic functional groups of EPS were quantitatively analyzed. The results indicated that the free amino group (-NH2) had the greater impact on the water-holding capacity of EPS than the acidic hydroxyl groups (-OH). Nevertheless, by Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS), the hydrophilic heteroatom classes (e.g. N:Cw) were found to be less sensitive to the varying oxidant dosage than the molecular saturation degree (e.g. weighted averages of double bond equivalents (DBEw) and aromatic index (AImod,w)). •OH modified the nitrogen-containing or oxygen-containing functional groups, but could not completely remove these hydrophilic functional groups from EPS macromolecules. Therefore, the potential competition for •OH between the hydrophilic functional groups and the unsaturated structure units of EPS was clarified, which guides directions that developing highly-efficient sludge conditioning approaches should be based on the selective removal of hydrophilic functional groups instead of improving •OH production efficiency.

Creation of quantum coherence with general measurement processes

Quantum measurement not only can destroy coherence but also can create it. Here, we estimate the maximum amount of coherence, one can create under a complete non-selective measurement process. For our analysis, we consider projective as well as POVM measurements. Based on our observations, we characterize the measurement processes into two categories, namely, the measurements with the ability to induce coherence and the ones without this ability. Our findings also suggest that the more POVM elements present in a measurement that acts on the quantum system, the less will be its coherence creating ability. We also introduce the notion of raw coherence in the POVMs that helps to create quantum coherence. Finally, we find a trade-off relation between the coherence creation, entanglement generation between system and apparatus, and the mixedness of the system in a general measurement setup.

Stopping Interference in Response Inhibition: Behavioral and Neural Signatures of Selective Stopping.

Response inhibition is an essential aspect of cognitive control that is necessary for terminating inappropriate preplanned or ongoing responses. Response-selective stopping represents a complex form of response inhibition where only a subcomponent of a multicomponent action must be terminated. In this context, a substantial response delay emerges on unstopped effectors after the cued effector is successfully stopped. This response delay has been termed the stopping interference effect. Converging lines of evidence indicate that this effect results from a global response inhibition mechanism that is recruited regardless of the stopping context. However, behavioral observations reveal that the stopping interference effect may not always occur during selective stopping. This review summarizes the behavioral and neural signatures of response inhibition during selective stopping. An overview of selective stopping contexts and the stopping interference effect is provided. A "restart" model of selective stopping is expanded on in light of recent neurophysiological evidence of selective and nonselective response inhibition. Factors beyond overt action cancellation that contribute to the stopping interference effect are discussed. Finally, a pause-then-cancel model of action stopping is presented as a candidate framework to understand stopping interference during response-selective stopping. The extant literature indicates that stopping interference may result from both selective and nonselective response inhibition processes, which can be amplified or attenuated by response conflict, task familiarity, and functional coupling.

The Role of Chaperone-Mediated Autophagy in Hepatitis C Virus-Induced Pathogenesis.

Lysosome incorporate and degrade proteins in a process known as autophagy. There are three types of autophagy; macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA). Although autophagy is considered a nonselective degradation process, CMA is known as a selective degradation pathway. All proteins internalized in the lysosome via CMA contain a pentapeptide KFERQ-motif, also known as a CMA-targeting motif, which is necessary for selectivity. CMA directly delivers a substrate protein into the lysosome lumen using the cytosolic chaperone HSC70 and the lysosomal receptor LAMP-2A for degradation. Hepatitis C virus (HCV) NS5A protein interacts with hepatocyte-nuclear factor 1α (HNF-1α) together with HSC70 and promotes the lysosomal degradation of HNF-1α via CMA, resulting in HCV-induced pathogenesis. HCV NS5A promotes recruitment of HSC70 to the substrate protein HNF-1α. HCV NS5A plays a crucial role in HCV-induced CMA. Further investigations of HCV NS5A-interacting proteins containing CMA-targeting motifs may help to elucidate HCV-induced pathogenesis.

Comparable prediction of breast cancer risk from a glimpse or a first impression of a mammogram

Expert radiologists can discern normal from abnormal mammograms with above-chance accuracy after brief (e.g. 500 ms) exposure. They can even predict cancer risk viewing currently normal images (priors) from women who will later develop cancer. This involves a rapid, global, non-selective process called “gist extraction”. It is not yet known whether prolonged exposure can strengthen the gist signal, or if it is available solely in the early exposure. This is of particular interest for the priors that do not contain any localizable signal of abnormality. The current study compared performance with brief (500 ms) or unlimited exposure for four types of mammograms (normal, abnormal, contralateral, priors). Groups of expert radiologists and untrained observers were tested. As expected, radiologists outperformed naïve participants. Replicating prior work, they exceeded chance performance though the gist signal was weak. However, we found no consistent performance differences in radiologists or naïves between timing conditions. Exposure time neither increased nor decreased ability to identify the gist of abnormality or predict cancer risk. If gist signals are to have a place in cancer risk assessments, more efforts should be made to strengthen the signal.

Community genomics: a community-wide perspective on within-species genetic diversity.

Community genomics: a community-wide perspective on within-species genetic diversity.

Doping and facet effects synergistically mediated interfacial reaction mechanism and selectivity in photocatalytic NO abatement

The surface atomic coordination and arrangement largely determine photocatalytic properties. Whereas, the intrinsic impact of surface microstructures on the reaction mechanism and pathway is still unclear. Herein, via constructing N-doped Bi2O2CO3 photocatalysts with diverse exposed facets, (1 1 0) and (0 0 1) facet, we testify that the pivotal roles of crystal facet and doping effect on the intermediate production and reactivity for photocatalytic nitric oxide (NO) abatement. The photoreactivity of N-doped Bi2O2CO3 is documented to be higher than that of the pure samples because of the enhanced light absorption and charge transfer. Further in situ probing experiments and theoretical calculations verify that the unique adsorption patterns and activated intermediates on the (1 1 0) facet facilitate the formation of final products and inhibit the generation of toxic NO2 by-product in terms of thermodynamics. More importantly, we found that the selective and nonselective oxidation processes are emerged over (1 1 0) and (0 0 1) facets of Bi2O2CO3, respectively.

One-рot синтез и строение изомерных арилзамещенных триазологексагидрохиназолинов

Aryl-substituted triazolohexahydroquinazolines have been synthesized by means of three-component condensation of pnitro(pbromo) benzaldehydes, cyclohexanone, 1,2,4-triazol-3-amine. A scheme of the reaction mechanism is proposed, which makes it possible to explain the features of the behavior of p-nitro(bromo) benzaldehydes in condensation reactions in comparison with their ortho-substituted analogs. It has been found that the movement of the substituent from the ortho- tо -para-position of the benzene ring while maintaining the general direction of the reaction has a decisive effect on the number and ratio of the formed isomers and leads to the absence of hydroxylated forms of triazolohexahydroquinazolines. The composition and structure of the products have been confirmed by the data of elemental analysis, IR and one-dimensional, two-dimensional NMR spectroscopy. One-pot synthesis of aryl-substituted triazohexahydroquinazolines is a non-selective process that leads to a mixture of isomers, the structure and ratio of which is determined by the nature and position of the substituent groups in the aldehyde component.

Nonselective etching of As and P based III‒V solar cell heterostructures with aqueous solutions of HIO3 and HCl

Etching characteristics of lattice-matched GaInP/GaAs/GaInNAsSb heterostructures by aqueous solutions of iodic acid (HIO3) and hydrochloric acid (HCl) is reported. The study aims at optimization of mesa fabrication process involved in the development of III‒V multijunction solar cells. The effects of temperature, agitation, etchant composition, and illumination on the etching selectivity are investigated. Varying the etchant composition and agitation rate at room temperature results in various mesa sidewall morphologies, ranging from rough surfaces and significant undercut to smoother sidewall profiles with only minor undercut. Especially, the undercut emerging in the GaInNAsSb junction, as well as in the AlInP layers, was observed for several etching conditions. Increasing the etching temperature also caused an unwanted increase in the selectivity, whereas reducing the temperature below the room temperature enhanced remarkably the formation of smooth morphology. Illumination during the etching resulted in a severe undercut in the GaAs junction, due to an increased selectivity caused by photoetching. This points out the need of controlled illumination condition to avoid unwanted reactions in wet etching of such multijunction structures. The etching process resulting in the best morphology was used for electrical isolation of triple-junction GaInP/GaAs/GaInNAsSb solar cells. The good photovoltaic performance exhibited by these devices proves the suitability of the nonselective etch process in developing multijunction solar cells.

Perrhenate Esters as Intermediates in Molecular Complexity-Increasing Reactions

AbstractAllylic alcohols form perrhenate esters upon reaction with Re2O7 or HOReO3. These species undergo nonstereospecific and nonregiospecific alcohol-transposition reactions through cationic intermediates. Sequencing these nonselective processes with reversible trapping by electrophiles results in cyclization reactions where regio- and stereocontrol are dictated by thermodynamics. The cationic intermediates can also be utilized as electrophiles in intra- or intermolecular dehydrative reactions with nucleophiles. These processes serve as the basis for applications in catalytic syntheses of a wide range of heterocyclic and carbocyclic structures that often show considerable increases in molecular complexity. This Account describes a sequence of events that started from a need to solve a problem for the completion of a natural product synthesis and evolved into a central element in the design of numerous new transformations that proceed under mild conditions from readily accessible substrates.1 Introduction2 Exploratory Studies3 Application to Spiroketal Synthesis4 Reactions with Epoxides as Trapping Agents5 Development of Dehydrative Cyclizations6 Bimolecular Reactions7 Spirocyclic Ether Formation8 Conclusions

The relative contribution of non-selection and selection processes in marine benthic assemblages

We tested the hypothesis that the ubiquity of marine meiofaunal nematodes and their indiscriminate passive dispersal create assemblages that are less limited by its environment; whereas the relatively smaller population sizes of macrofauna, associated with their ability to track environmental conditions before settlement, renders their distribution more environmentally-restricted. We compared the empirical distribution of macrofauna and nematode species with that of communities simulated under different assumptions of selection (e.g. environmental filtering) and non-selection (e.g. dispersal limitation) processes. Selection processes were the prime driver of both meio- and macrofauna assemblages, with rare species strongly contributing to this component. The total number of species explained by non-selection processes was 27% higher in nematodes than in macrofauna. Our results underline the importance of a species-level approach to determine the contribution of selection and non-selection assembly processes. Moreover, they highlight the important yet overlooked role of dispersal and stochastic processes in determining species dynamics.

Contact Resistivity of Highly Doped Si:P, Si:As, and Si:P:As Epi Layers for Source/Drain Epitaxy

With the downscaling of the CMOS transistor dimensions, the reduction of the external resistance is playing an important role in the overall device optimization. For NMOS devices, highly P-doped Si:P epitaxy is typically used to lower the source/drain and contact resistance [1]. In this work we report on the use of As as a dopant and compare the layer characteristics and contact resistivity of highly doped epitaxial Si:P, Si:As, Si:P:As layers and Si:As/Si:P bi-layers grown on 300 mm Si (100) substrates. As is found to incorporate more efficiently into the epi layer compared to P but gives rise to a lower tensile strain [2]. Good quality epitaxial layers can be obtained with As concentrations as high as 10% (Fig. 1). In comparison to Si:P a reduced diffusion is confirmed for Si:As after spike and laser anneal, making the layer an interesting candidate for an extension liner [2,3]. In general, the dopant activation and carrier mobility of the Si:As and Si:P:As layers after epitaxy is lower than that of Si:P as determined by micro-Hall measurements (Fig. 2a). Only in some specific cases (e.g. for concentrations below ~3% and non-selective processes), we can observe an enhanced activation due to the co-doping of P and As which we attribute to an energetically favorable AsxV vacancy complex formation at low As concentration [4]. The contact resistivity was extracted using a Multi-Ring Circular Transmission Line Model for a Ti based contacting scheme [5]. The contact resistivity of Si:P, Si:As and Si:P:As layers with different concentrations obtained by selective and non-selective epitaxy was compared and the effect of a post-epitaxy millisecond laser anneal was studied (Fig. 2b). Excellent contact resistivities down to ~2E-9 Ohm.cm2 could be found at high doping levels. A clear correlation was observed between the resistivity/contact resistivity and activation levels obtained by micro-Hall measurements. Within the set of studied processes, As doping is not bringing substantially lower contact resistivities compared to P doping, for comparable chemical doping concentrations. Still, As remains an attractive dopant for extension liners because of its lower diffusion constant.

Contact Resistivity of Highly Doped Si:P, Si:As, and Si:P:As Epi Layers for Source/Drain Epitaxy

In this work we report on the contact resistivity of highly doped epitaxial Si:P, Si:As and Si:P:As layers grown on 300 mm Si (100) substrates. The contact resistivity was extracted using a Multi-Ring Circular Transmission Line Model for a Ti based contacting scheme. Both selective and non-selective epitaxy processes were used and the effect of a post-epitaxy millisecond laser anneal was studied. Excellent contact resistivities down to ~2E-9 Ohm.cm2 could be found at high doping levels. A clear correlation was observed between the resistivity/contact resistivity and activation levels obtained by micro-Hall measurements. Although As doping is not bringing substantially lower contact resistivities compared to P doping, we observe a small beneficial effect. As also remains an attractive dopant for extension liners because of its lower diffusion constant.

Microautophagy – distinct molecular mechanisms handle cargoes of many sizes

Autophagy is fundamental for cell and organismal health. Two types of autophagy are conserved in eukaryotes: macroautophagy and microautophagy. During macroautophagy, autophagosomes deliver cytoplasmic constituents to endosomes or lysosomes, whereas during microautophagy lytic organelles take up cytoplasm directly. While macroautophagy has been investigated extensively, microautophagy has received much less attention. Nonetheless, it has become clear that microautophagy has a broad range of functions in biosynthetic transport, metabolic adaptation, organelle remodeling and quality control. This Review discusses the selective and non-selective microautophagic processes known in yeast, plants and animals. Based on the molecular mechanisms for the uptake of microautophagic cargo into lytic organelles, I propose to distinguish between fission-type microautophagy, which depends on ESCRT proteins, and fusion-type microautophagy, which requires the core autophagy machinery and SNARE proteins. Many questions remain to be explored, but the functional versatility and mechanistic diversity of microautophagy are beginning to emerge.

Influence of Seawater on the Degree of Entrainment in the Flotation of a Synthetic Copper Ore

Froth flotation is a process in which hydrophobic particles attach to bubbles forming particle–bubble aggregates, which are transported to the top section of the cell where they overflow to form the concentrate. Particles also reach the concentrate by entrainment, which is a non-selective process that leads to low concentrate grades. The objective of this work was to study and compare the degree of entrainment measured using three methods, in fresh and seawater, and using methyl isobutyl carbinol (MIBC) and DF-250 as frothers. The experimental results indicated that the degree of entrainment decreased in seawater. Besides, water recovery was lower in the experiments with seawater regardless of the frother that was used in the experiments, which correlated with the observed low degrees of entrainment. It is proposed that the reduction of entrainment and water recovery in seawater can be explained by a reduction of air recovery and/or more bubble coalescence in the froth. It is also proposed that surfactant diffusion/convection from the lamellae to the Plateau borders in the froth is reduced in seawater, which reduces the surface tension gradients, and thus the restoring liquid flow from the Plateau borders to the lamellae.

The possible routes of microplastics uptake in sea cucumber Holothuria cinerascens (Brandt, 1835)

Investigating the routes of microplastic uptake in sea cucumber is crucial in this plastics pollution age considering their non-selective feeding process, nutritional, biomedical and ecological importance. The guts, respiratory trees and coelomic fluids of Holothuria cinerascens were sampled and examined for microplastic after exposure to fluorescent microplastic fragments and microfibres. The madreporite pore size was also determined. 90% of the animals sampled ingested microplastic fragments via their feeding tentacles. Microplastic ingested ranged from 0 to 24 fragments intestine-1 (8.7 ± 2.11). All (100%) the animals sampled had microfibre in their coelomic fluid ranging from 32 to 227 microfibres coelom-1 (79.58 ± 10.53). Microfibres were found attached to all undigested respiratory trees examined. Microfibres were also found in 57.8% of digested respiratory trees with a range of 0–12 microfibres respiratory tree−1 (1.74 ± 0.66). Notably, there was no fluorescent microplastic fragments/microfibres found in the gut, coelomic fluid, and respiratory trees of animals in the control group. The madreporite pore size ranged from 0.59 to 2.90 μm (1.22 ± 0.03 μm). Microfibres found in the coelomic fluid were transferred from the respiratory trees because the size of microfibre used for this experiment was assumed larger for it to have passed through the gut into the coelom. Although the madreporite pore size is smaller than microfibre used in this study, madreporite can act as another channel to transport nanoplastics from the coelom into the animal tissue. This study showed that sea cucumber uptake microplastics from the environment using the feeding tentacles and the respiratory trees. Chemicals desorption from microplastics into H. cinerascens when ingested may pose a risk to the animals and their consumers. Further study is required to determine if microfibres transfer from the respiratory trees to the coelomic fluid is dependent on microfibre concentration and water temperature.

Theoretical design and experimental investigation on highly selective Pd particles decorated C3N4 for safe photocatalytic NO purification

Rational design of highly active and selective photocatalyst for NO removal is significant for the commercial application of photocatalytic technology because the secondary byproduct caused by insufficient and non-selective pollutant oxidation process is a major challenge. In this work, Pd nanoparticles decorated C3N4 (PdCN) is designed by density functional theory (DFT) at first. The PdCN exhibits superiority to CN in terms of both kinetics and thermodynamics performances, as reflected in the lower activation barrier of rate-determining step and higher selectivity for the final product (nitrate) instead of toxic intermediate (NO2). The as-designed highly selective and efficient photocatalyst is then fabricated by a facile method with an extremely low content of Pd particles supported on C3N4. Compared to bare CN, the synthesized PdCN exhibits highly enhanced purification of NO in air and strong inhibition of toxic NO2 by-product as supported by in-situ DRIFTS investigation, which is consistent with the theoretical prediction. This work is a typical demonstration of setting up a bridge between theory and experiment to give a promising way to the rational design of advanced photocatalysts and atomic understanding of the reaction mechanism.