Many human diseases are associated with mutations causing protein misfolding and aggregation in the endoplasmic reticulum (ER). ER-associated degradation (ERAD) is a principal quality-control ...mechanism responsible for targeting misfolded ER proteins for cytosolic degradation. However, despite years of effort, the physiological role of ERAD in vivo remains largely unknown. Several recent studies have reported intriguing phenotypes of mice deficient for ERAD function in specific cell types. These studies highlight that mammalian ERAD has been designed to perform a wide-range of cell-type-specific functions in vivo in a substrate-dependent manner.
Summary
Starch degradation is a necessary process determining banana fruit quality during ripening. Many starch degradation‐related genes are well studied. However, the transcriptional regulation of ...starch degradation during banana fruit ripening remains poorly understood. In this study, we identified a MYB transcription factor (TF) termed MaMYB3, as a putative protein binding the promoter of MaGWD1, a member of glucan water dikinase (GWD) family which has been demonstrated as an important enzyme of starch degradation. MaMYB3 was ripening‐ and ethylene‐repressible, and its expression was negatively correlated with starch degradation. Acting as a nucleus‐localized transcriptional repressor, MaMYB3 repressed the transcription of 10 starch degradation‐related genes, including MaGWD1, MaSEX4, MaBAM7‐MaBAM8, MaAMY2B, MaAMY3, MaAMY3A, MaAMY3C, MaMEX1, and MapGlcT2‐1, by directly binding to their promoters. Interestingly, a previously identified activator of starch degradation‐related genes, MabHLH6, was also suppressed by MaMYB3. The ectopic overexpression of MaMYB3 in tomato down‐regulated the expression of starch degradation‐related genes, inhibited starch degradation and delayed fruit ripening. Based on these findings, we conclude that MaMYB3 negatively impacts starch degradation by directly repressing starch degradation‐related genes and MabHLH6, and thereby delays banana fruit ripening. Collectively, our study expands our understanding of the complex transcriptional regulatory hierarchy modulating starch degradation during fruit ripening.
Significance Statement
MaMYB3 negatively impacts starch degradation by the direct repression of MabHLH6 and starch degradation‐related genes, and thus delays banana fruit ripening. Our findings illustrate the complex transcriptional regulatory hierarchy modulating starch degradation during fruit ripening.
Abstract This review presents a critical survey of all experimental data about the low temperature degradation of zirconia (often referred to as “aging”) due to the tetragonal-to-monoclinic ...transformation, which have been collected at temperatures of interest for dental application (room temperature to about 100 °C). It is shown that the main factors affecting the aging phenomenon are (i) the stabilizer type and content, (ii) the residual stress and (iii) the grain size. It is also shown that extrapolating the low temperature degradation rate from accelerated aging tests can lead to unacceptable conclusions about the lifetime of the zirconia-based components. Finally, based on the experimental evidence, a set of engineering guidelines for the use of zirconia in restorative and prosthetic dentistry is proposed.
Hygrothermal conditioning on the chemical, thermal and mechanical properties of aliphatic polyketone terpolymer, ethylene-propylene-carbon monoxide (EPCO), were investigated under high temperature ...fluid transport conditions. The DSC results suggest the effect of hygrothermal treatment and exposure time on the advancement of chain scission leading to an increase in crystallinity induced by chemi-crystallization, which was confirmed by FTIR results. TGA results of EPCO correspond to reductions of thermal stability with decreases in T5% and Tmax characteristic temperatures by 19% and 10%, respectively. The yield stress, stiffness and dynamic storage modulus increased with degradation time. However, decreases in the elongation at break were observed after prolonged periods of degradation due to the embrittlement resulting from polymer chain scission.
•Prolonged hygrothermal degradation of Polyketone results to chain scission phenomenon.•Thermal stability declines with increased in hygrothermal degradation conditioning.•Mechanical property and performance declined arising from changes in crystallinity.•Prolonged degradation retained better mechanical properties at elevated temperatures from dynamic mechanical tests.
In this work, sixteen typical chlorinated and brominated aromatic disinfection by-products (DBPs) were selected as examples to investigate their different degradation mechanisms initiated by HO• and ...SO4•-. Addition reactions were the main mode of degradation of DBPs by HO•, while SO4•- dominated H-abstraction reactions and single electron transfer reactions. Chlorinated compounds had higher reactivity than brominated compounds. Furthermore, substituents with stronger electron-donating effects promoted the electrophilic reaction of DBPs with the two radicals. In addition, we developed a model based on the chemical properties LUMO, fmax-, and hardness for predicting the average reaction energy barriers for the initial reactions of DBPs with HO• and SO4•-. The model had good predictive performance for the difficulty of degradation of different DPBs by HO• and SO4•-, with R2 values of 0.85 and 0.87, respectively. Through the degradation efficiency simulation, we found that longer reaction times, higher oxidant concentrations and lower pollutant concentrations were more favorable for the removal of DBPs. The UV/PDS process showed better degradation of DBPs than the UV/H2O2 process. In addition, most degradation products of DBPs exhibited less toxicity to aquatic organisms than their parent compounds. This study provided theoretical guidance for the degradation and removal of other aromatic DBPs at the molecular level.
Florfenicol (FF, C12H14Cl2FNO4S), an emerging halogenated organic contaminant of concern was effectively degraded in water by sulfidized nanoscale zerovalent iron (S-nZVI). Sulfidized nZVI (62.5 m2 ...g–1) that was prepared using a one-step method resulted in small Fe0/Fe-sulfide particles that were more stable against aggregation than unsulfidized nZVI (10.2 m2 g–1). No obvious removal of FF was observed by unsulfidized nZVI. S-nZVI degraded FF, having a surface area normalized reaction rate constant of 3.1 × 10–4 L m–2 min–1. The effects of the S/Fe molar ratio, initial FF concentration, initial pH, temperature, and water composition on the removal of FF by S-nZVI, and on the formation of reaction products, were systematically investigated. Both dechlorination and defluorination were observed, resulting in four degradation products (C12H15ClFNO4S, C12H16FNO4S, C12H17NO4S, and C12H17NO5S). High removal efficiencies of FF by S-nZVI were achieved in groundwater, river water, seawater, and wastewater. The reactivity of S-nZVI was relatively unaffected by the presence of both dissolved ions and organic matter in the waters tested.
Lithium‐rich layered oxides (LLOs) are promising candidate cathode materials for safe and inexpensive high‐energy‐density Li‐ion batteries. However, oxygen dimers are formed from the cathode material ...through oxygen redox activity, which can result in morphological changes and structural transitions that cause performance deterioration and safety concerns. Herein, a flake‐like LLO is prepared and aberration‐corrected scanning transmission electron microscopy (STEM), in situ high‐temperature X‐ray diffraction (HT‐XRD), and soft X‐ray absorption spectrum (sXAS) are used to explore its crystal facet degradation behavior in terms of both thermal and electrochemical processes. Void‐induced degradation behavior of LLO in different facet reveals significant anisotropy at high voltage. Particle degradation originates from side facets, such as the (010) facet, while the close (003) facet is stable. These results are further understood through ab initio molecular dynamics calculations, which show that oxygen atoms are lost from the {010} facets. Therefore, the facet degradation process is that oxygen molecular formed in the interlayer and accumulated in the ab plane during heating, which result in crevice‐voids in the ab plane facets. The study reveals important aspects of the mechanism responsible for oxygen ‐anionic activity‐based degradation of LLO cathode materials used in lithium‐ion batteries. In particular, this study provides insight that enables precise and efficient measures to be taken to improve the thermal and electrochemical stability of an LLO.
Void‐induced facet degradation behavior of LLO is found in both thermally and during long‐term electrochemical cycling at high voltage. The facet degradation process of heating is that oxygen molecular formed in the interlayer and accumulated in the ab plane during heating, which result in crevice voids in the ab plane facets.
Polyethylene terephthalate (PET) is one of the most important synthetic polymers used today. Unfortunately, the polymers accumulate in nature and to date no highly active enzymes are known that can ...degrade it at high velocity. Enzymes involved in PET degradation are mainly α- and β-hydrolases, like cutinases and related enzymes (EC 3.1.1). Currently, only a small number of such enzymes are well characterized. In this work, a search algorithm was developed that identified 504 possible PET hydrolase candidate genes from various databases. A further global search that comprised more than 16 Gb of sequence information within 108 marine and 25 terrestrial metagenomes obtained from the Integrated Microbial Genome (IMG) database detected 349 putative PET hydrolases. Heterologous expression of four such candidate enzymes verified the function of these enzymes and confirmed the usefulness of the developed search algorithm. In this way, two novel and thermostable enzymes with high potential for downstream application were partially characterized. Clustering of 504 novel enzyme candidates based on amino acid similarities indicated that PET hydrolases mainly occur in the phyla of
,
, and
Within the
, the
,
, and
were the main hosts. Remarkably enough, in the marine environment, bacteria affiliated with the phylum
appear to be the main hosts of PET hydrolase genes, rather than
or
, as observed for the terrestrial metagenomes. Our data further imply that PET hydrolases are truly rare enzymes. The highest occurrence of 1.5 hits/Mb was observed in sequences from a sample site containing crude oil.
Polyethylene terephthalate (PET) accumulates in our environment without significant microbial conversion. Although a few PET hydrolases are already known, it is still unknown how frequently they appear and with which main bacterial phyla they are affiliated. In this study, deep sequence mining of protein databases and metagenomes demonstrated that PET hydrolases indeed occur at very low frequencies in the environment. Furthermore, it was possible to link them to phyla that were previously not known to harbor such enzymes. This work contributes novel knowledge on the phylogenetic relationships, the recent evolution, and the global distribution of PET hydrolases. Finally, we describe the biochemical traits of four novel PET hydrolases.
•Fuel cell state of health is defined using the voltage at rated current.•Polarization curves of degraded fuel cell is modelled base on state of health.•A degradation adaptive strategy using state of ...health as input is proposed.•Power distribution changes adaptively during the whole lifetime of the fuel cell.•Fuel economy of heavily degraded fuel cell vehicle is improved by 2.26–2.90%
Most studies on fuel cell hybrid electric vehicle energy management have focused on fuel economy. However, it is also important to consider the rapid degradation of the fuel cell. Therefore, a degradation-adaptive energy management strategy is proposed in this paper. The strategy can adaptively change the power distribution between different power sources using the fuel cell state-of-health. First, a novel degradation model is established for the fuel cell. The degradation model combines the polarisation curves of the fuel cell system under different state-of-health conditions and fuel cell efficiency models. An unbalanced degradation of the fuel cell at different current densities is shown in the degradation model. The proposed strategy is modified from an instantaneous optimisation energy management strategy by including state-of-health data. Accordingly, it is possible to provide optimised control based on the decrease in efficiency, thereby taking advantage of the unbalanced degradation. The proposed strategy can adaptively adjust the power distribution during degradation to get a higher energy efficiency over entire lifetime of fuel cell. The proposed strategy is adaptive to different degradation rates and consumes a small amount of computing resources, which ensure the feasibility of real-world implication. The performance of the proposed strategy is compared with that of the original strategy via simulation. The proposed strategy can optimise the fuel economy by 1.52–2.06% and 2.26–2.90% for a half and seriously degraded fuel cell, respectively. The results reveal that the proposed strategy provide an effective approach to improving the fuel economy of degraded fuel cell hybrid electric vehicles.
Motor fault diagnosis is imperative to enhance the reliability and security of industrial systems. However, since motors are often operated under nonstationary conditions, the high complexity of ...vibration signals raises notable difficulties for fault diagnosis. Therefore, considering the special physical characteristics of motor signals under nonstationary conditions, in this article, we propose a multiscale kernel based residual convolutional neural network (CNN) for motor fault diagnosis. Our contributions mainly fall into two aspects. First, we notice that each motor fault category has various patterns in vibration signals due to the changing operational conditions of the motor. To capture these patterns, a multiscale kernel algorithm is applied in the CNN architecture. Second, since the motor vibration signals are made up of many different components from different transfer paths, they are very complex and variable. To enable the architecture to extract fault features from deep and hierarchical representation spaces, sufficient depth of the network is needed, which will lead to the degradation problem. In the proposed method, residual learning is embedded into the multiscale kernel CNN to avoid performance degradation and build a deeper network. To validate the effectiveness of the proposed networks, a normal motor and five motors with different failures are tested. The results and comparisons with state-of-the-art methods highlight the superiority of the proposed method.
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