The coincidence and superposition of flood processes from different rivers and regions tend to form compound flood events, determined by spatial relationship between diverse flood processes that ...cannot be accurately depicted and evaluated by existing dependence analysis methods. A framework, integrating multi‐dimensional vine copula model and dependence evaluation system, was developed with a testing‐oriented application to explore underlying dependence between two kinds of extreme runoff series (peak discharge and flood volume) extracted from the identified compound flood events in the upper reaches of the Yangtze River. Multi‐dimensional regular vine (R‐vine) copula models were established to depict the complex and diverse dependence, and corresponding vine structure was specified by the vine structure array that can reflect the sequence of tributaries flowing into the main stream and the spatial locations of different hydrometric stations. Dependence magnitude and association status were calculated and compared according to the optimal R‐vine copula models and information theory. Comparison with existing methods demonstrated that dependence evaluation system could reflect nonlinear and local dependence characteristics and eliminate the effect of extreme runoff series from other hydrometric station on the dependence. The association status between different extreme runoff series of the upper Yangtze River and its tributaries were diverse in view of the impact of tributary flood inflow. The proposed framework can be regarded as an effective way for dependence modeling and evaluation of compound floods, thus providing a scientific reference for the risk analysis of water resources systems.
Key Points
Vine structure is specified by the sequence of tributaries flowing into main stream and spatial locations of hydrological stations
Dependence evaluation system determines dependence magnitude and association status through R‐statistic and interaction gain
Extreme runoff series of the same hydrometric station show distinct association status
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The stimuli-responsive polypeptides have drawn extensive attention because of their promising applications in biotechnology considering their biocompatibility, biodegradability, and bioactivity. In ...this tutorial review, we summarize the most recent progress in this area, including thermo-, redox-, photo-, and biomolecule responsive polypeptides over the past decade. The design and synthesis of stimuli-responsive polypeptides will be briefly introduced. The correlation between the structure and properties, particularly the effects of polypeptide conformation, will be emphasized here. In addition, the applications of stimuli-responsive polypeptides in controlled drug release and tissue engineering are briefly discussed.
This tutorial review summarizes the most recent progress in stimuli-responsive polypeptides over the past decade.
Objective
To propose a new hypothesis that GABAergic dysfunction in excitatory and inhibitory (E/I) imbalance drives the pathogenesis of Alzheimer's disease (AD).
Background
Synaptic dysfunction and ...E/I imbalance emerge decades before the appearance of cognitive decline in AD patients, which contribute to neurodegeneration. Initially, E/I imbalance was thought to occur first, due to dysfunction of the glutamatergic and cholinergic systems. However, new evidence has demonstrated that the GABAergic system, the counterpart of E/I balance and the major inhibitory neurotransmitter system in the central nervous system, is altered enormously and that this contributes to E/I imbalance and further AD pathogenesis.
New hypothesis
Alterations to the GABAergic system, induced by multiple AD pathogenic or risk factors, contribute to E/I imbalance and AD pathogenesis.
Major challenges for the hypothesis
This GABAergic hypothesis accounts for many critical questions and common challenges confronting a new hypothesis of AD pathogenesis. More specifically, it explains why amyloid beta (Aβ), β‐secretase (BACE1), apolipoprotein E4 gene (APOE ε4), hyperactive glia cells, contributes to AD pathogenesis and why age and sex are the risk factors of AD. GABAergic dysfunction promotes the spread of Aβ pathology throughout the AD brain and associated cognitive impairments, and the induction of dysfunction induced by these varied risk factors shares this common neurobiology leading to E/I imbalance. In turn, some of these factors exacerbate GABAergic dysfunction and E/I imbalance. Moreover, the GABAergic system modulates various brain functions and thus, the GABAergic hypothesis accounts for nonamnestic manifestations. Furthermore, corrections of E/I balance through manipulation of GABAergic functions have shown positive outcomes in preclinical and clinical studies, suggesting the potential of the GABAergic system as a therapeutic target in AD.
Linkage to other major theories
Dysfunction of the GABAergic system is induced by multiple critical signaling pathways, which include the existing major theories of AD pathogenesis, such as the Aβ and neuroinflammation hypotheses. In a new perspective, this GABAergic hypothesis accounts for the E/I imbalance and related excitotoxicity, which contribute to cognitive decline and AD pathogenesis. Therefore, the GABAergic system could be a key target to restore, at least partially, the E/I balance and cognitive function in AD patients.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•Synthesis of octahedral ruthenium cyclohexylphosphine and cyclohexylphosphido complexes.•Synthesis of secondary alkoxyphosphine complexes.•Computational interrogation of trigonal ...phsophenium/pyramidal phosphido dichotomy.•Circumstantial evidence for hydride-phosphenium migratory insertion coupling.
The reaction of RuHCl(CO)L3 (L = PPh3) with cyclohexylphosphine (PH2Cy) affords RuHCl(CO)L2(PH2Cy), protonation of which in acetonitrile with HX affords RuCl(NCMe)(CO)L2(PH2Cy)X (X = ClO4, OTf, PF6) salts while HCl provides RuCl2(CO)L2(PH2Cy). The labile chloride and/or acetonitrile ligands are replaced by CO, CNC6H2Me3-2,4,6, Et2NCS2– or Tp– (Tp = hydrotris(pyrazolyl)borate) to provide RuCl(CO)2L2(PH2Cy)+, RuCl(CO)(CNC6H2Me3-2,4,6)L2(PH2Cy)+, Ru(S2CNEt2)(CO)L2(PH2Cy)+ and Ru(CO)L(Tp)(PH2Cy)+ salts. Deprotonation of RuCl(CO)2L2(PH2Cy)OTf in benzene affords RuCl(PHCy)(CO)2L2, but in methanol the secondary methoxyphosphine complex Ru(CO)2L2{PH(OMe)Cy} is obtained, as is Ru(CO)(CNC6H2Me3-2,4,6)L2{PH(OMe)Cy} from RuCl(CO)(CNC6H2Me3-2,4,6)L2(PH2Cy)OTf. The reactions of Ru(CO)2L2{PH(OMe)Cy} with CO, CNC6H2Me3-2,4,6 or dppe afford Ru(CO)3L{PH(OMe)Cy}, Ru(CO)2(CNC6H2Me3-2,4,6)L2{PH(OMe)Cy} or Ru(CO)2(dppe){PH(OMe)Cy}, resectively, in each case demonstrating a preference for dissociation of PPh3 rather than PH(OMe)Cy. Aerial oxidation of Ru(CO)2L2{PH(OMe)Cy} results in oxidation of one carbonyl ligand with formation of the carbonato complex Ru(O2CO)(CO)L2{PH(OMe)Cy}. The reaction of Ru(CO)2L2{PH(OMe)Cy} with ethynyl benzene provides two diastereomers of RuH(CCPh)(CO)2L{PH(OMe)Cy}, while with anhydrous HCl, the cyclohexyl phosphine complex RuCl2(CO)L2(PH2Cy) is observed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Riverine water temperature (WT) is a crucial factor affecting habitat quality and ecological effect of aquatic ecosystems. To accurately quantify and classify WT variation features caused by climate ...change and reservoir construction and operation, a framework was developed that integrates multivariate vine copula model for accurately reconstructing the WT process and general evaluation indicators for comprehensively characterizing of WT variation. In this framework, month‐wise R‐vine copula models were employed to depict the multivariate dependence structure between WT and related hydrometeorological factors, and the change of WT process in the fluctuation range and thermal deviation was analogized as the change of simple harmonic wave in amplitude and phase. A testing‐oriented application of this framework in Yichang section of the Yangtze River highlighted that climate change and the Three Gorges Reservoir (TGR) dominated or participated in the fluctuation range changing and phase deviation of different monthly WT processes, as the ratios of affected months were 1.08:1 and 1.25:1 during the construction phase, and 1:2 and 1:1.28 during the operation phase. WT process also exhibited diverse monthly variation trends during construction and operation phases of the TGR. Therefore, it is inappropriate to neglect the impact of the TGR construction phase and climate change on WT variation. The proposed framework achieved systematic quantification and attribution analysis of WT variation, thereby providing an enhanced understanding of the variation characteristics of river thermal regimes under the individual and combined effects of climate change and artificial reservoir. Considering the significant influence of WT variation on aquatic organism reproduction, the identification of the sources and categories of monthly WT variation can also serve as a foundation for future targeted thermal and hydrological regime regulation, aiming to protecting aquatic species and preventing biodiversity loss.
The testing‐oriented application of this framework achieved a truly quantitative evaluation for the impact of the Three Gorges Reservoir (TGR) and climate change on downstream water temperature (WT) variation features, thus demonstrating its high reliability and practicability. It is inappropriate to neglect the impact of climate change and reservoir construction on WT variation because the TGR and climate change dominate or participate in different monthly WT variation features, and WT variation appears complex and opposite characteristics during the construction and operation phases of the TGR.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•(Zn, Mn) modified lead-free BiFeO3–BaTiO3 piezoceramics were successfully prepared through the sol–gel method.•Low oxygen vacancy content and less charged defects result in a small leakage current ...density.•0.7BiFe0.92Zn0.04Mn0.04O3–0.3BaTiO3 ceramic displays real and excellent ferroelectric property with 2Pr = 94.6 μC/cm2.•Excellent piezoelectric constant (d33 = 271 pC/N) and piezoelectric actuator constant (d*33 = 441 pm/V) were obtained.
Lead-free 0.7BiFe1–2xZnxMnxO3–0.3BaTiO3 (BFZMx–BT) piezoceramics were prepared through the sol–gel method followed by a two-step sintering process. The crystal structure and microstructure were investigated by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy, which revealed that the addition of Zn and Mn ions resulted in a noticeable modification of the microstructure. The BF–BT modification through (Zn, Mn) equivalent codoping induces grain size variation and oxygen vacancies, resulting in an enhancement in the Curie temperature, dielectric properties, polarization magnitude, and strain response. A large remnant polarization (2Pr = 94.6 μC/cm2), low leakage current (7.94 × 10−6 A/cm2), high Curie temperature (473 °C), excellent piezoelectric constant (d33 = 271 pC/N), high unipolar strain (0.353%), and high piezoelectric actuator constant (d33* = 441 pm/V) were obtained for BFZMx–BT ceramics with x = 0.04. These results not only demonstrate the remarkable effect of (Zn, Mn) codoping on the BiFeO3-based piezoceramics, but may also shed light on the development of advanced piezoelectric materials with high performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A 31-year-old woman was seen with contractures in her fingers and toes, carpal inversion, dysarthria, dysphagia, hypertonia, decreased tendon reflexes, absence of Babinski sign, and no psychiatric ...problems and significant global atrophy. What is your diagnosis?
•Complexing ligands had contrasting effect on Mn(II)/PMS and Mn(II)/PDS systems.•EDTA and NTA greatly enhanced the oxidation of contaminants in Mn(II)/PMS system.•Formation of Mn(III) species was an ...essential step for contaminants degradation.•Mn(V) but not free radicals was the dominant reactive oxidant.
In recent years, the activation of persulfates (peroxydisulfate (PDS) and peroxymonosulfate (PMS)) via transition metal ions for contaminants degradation has received extensive attention in water treatment. There has been growing interest on the mechanism (radical versus non-radical pathway) of activation processes. Interestingly, in contrast to copper, iron or cobalt ions regarded as effective activators for persulfates, manganese ion (Mn(II)) is inefficient for persulfates activation. Inspired by the enhanced stability of manganese species by ligands, this study for the first time systematically investigated the Mn(II)/persulfates with different ligands as a novel oxidation technology. UV-vis spectrometry, chemical probing method and mass spectrometry were used to explore the reactive intermediate (free radical versus high-valent manganese species) therein. It was surprisingly found that the oxidation efficiency of Mn(II)/ligand/persulfates system was highly dependent on the nature of persulfates and ligands. Mn(II) chelated by amino ligands such as ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetate (NTA) could efficiently trigger the oxidation of contaminants (e.g., recalcitrant compounds nitrophenol, benzoic acid and atrazine) by PMS, suggesting a promising Mn(II)/ligand/PMS technology for environmental decontamination especially under manganese-rich conditions. High-valent Mn species (Mn(V)) but not free radicals was demonstrated to be the dominant reactive intermediate, where Mn(III) species played a vital role in Mn(V) generation. The formation of Mn(III) species was found to be affected by the reactivity of persulfates and the type of ligands, thus influencing its further oxidation to Mn(V) species. This study presents a new oxidation process based on the combination of PMS and Mn(II) complex and broadens the knowledge of persulfates activation as well as manganese chemistry for decontamination in water treatment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A rocking-chair aqueous proton battery is assembled by using dipyridophenazine and indium hexacyanoferrate as the anode and cathode materials, respectively. The reversible amination of redox-active ...phenazine moieties in dipyridophenazine and fast intercalation-deintercalation of protons in hexacyanoferrate enable the aqueous proton battery to achieve a reversible specific capacity of 37 mA h g
−1
at 1 A g
−1
, good cycling stability with 76.1% capacity retention over 3000 cycles and excellent rate capability.
A high-performance aqueous proton battery is fabricated by pairing a dipyridophenazine anode with an indium hexacyanoferrate cathode in a pure H
2
SO
4
electrolyte.
In recent years, the number of sequences of diverse species submitted to GenBank has grown explosively and not infrequently the data contain errors. This problem is extensively recognized but not for ...invalid or incorrectly identified species, sample mixed-up, and contamination. DNA barcoding is a powerful tool for identifying and confirming species and one very important application involves forensics. In this study, we use DNA barcoding to detect erroneous sequences in GenBank by evaluating deep intraspecific and shallow interspecific divergences to discover possible taxonomic problems and other sources of error. We use the mitochondrial DNA gene encoding cytochrome b (Cytb) from turtles to test the utility of barcoding for pinpointing potential errors. This gene is widely used in phylogenetic studies of the speciose group. Intraspecific variation is usually less than 2.0% and in most cases it is less than 1.0%. In comparison, most species differ by more than 10.0% in our dataset. Overlapping intra- and interspecific percentages of variation mainly involve problematic identifications of species and outdated taxonomies. Further, we detect identical problems in Cytb from Insectivora and Chiroptera. Upon applying this strategy to 47,524 mammalian CoxI sequences, we resolve a suite of potentially problematic sequences. Our study reveals that erroneous sequences are not rare in GenBank and that the DNA barcoding can serve to confirm sequencing accuracy and discover problems such as misidentified species, inaccurate taxonomies, contamination, and potential errors in sequencing.
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