321 research outputs found
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Bonding and electronic properties of linear diethynyl oligothienoacene-bridged diruthenium complexes and their oxidized forms
A series of five diruthenium diethynyl
complexes based on α,β-fused oligothienoacenes in the
core of the bridging ligands [{Ru(dppe)Cp*}<sub>2</sub>(μ-CC–L–CC)]
[dppe = 1,2-bis(diphenylphosphino)ethane, Cp* = η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>; L = thieno[3,2-<i>b</i>]thiophene
(<b>4</b>), thieno[2,3-<i>b</i>]thiophene (<b>5</b>), 3,4-dimethylthieno[2,3-<i>b</i>]thiophene (<b>6</b>), dithieno[3,2-<i>b</i>:2′,3′-<i>d</i>]thiophene (<b>7</b>), and thieno[3,2-<i>b</i>]thieno[2′,3′:4,5]thieno[2,3-<i>d</i>]thiophene (<b>8</b>)] have been synthesized and
fully characterized electrochemically and spectroscopically. Elongation
of the redox noninnocent oligothienoacene bridge core causes a smaller
potential difference between the initial two anodic steps, not seen
for free dialkyl oligothienoacenes, and increased positive charge
delocalization over the conjugated bridge backbone. The highest occupied
molecular orbital of the parent complexes resides predominantly on
the oligothienoacene core, with strong participation of the ethynyl
linkers and slightly smaller contribution from the metallic termini.
This bonding character makes the initial one-electron oxidation symmetrical,
as revealed by combined voltammetric and spectroscopic (IR, UV–vis–near-IR,
and electron paramagnetic resonance) methods as well as density functional
theory (DFT) and time-dependent DFT calculations of truncated and
selected nontruncated models of the studied series. The remarkable
gradual appearance of two CC stretching absorptions in the
IR spectra of the monocationic diethynyl complexes is ascribed to
increasing vibronic coupling of the IR-forbidden ν<sub>s</sub>(CC) mode of the oxidized −[CC–core–CC]<sup>+</sup>– bridge with a low-lying π–π*(intrabridge)/metal-to-ligand
charge-transfer electronic transition in the near-to-mid-IR spectral
region
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Mononuclear piano-stool iron 2-ethynylbenzo[b]thiophene complex: crystal structure and reversible oxidation studied by spectro-electrochemical and DFT methods
A mononuclear iron complex with 2-ethynylbenzo[b]thiophene C-coordinated to the
(η5
-Cp*)(η2
-dppe)Fe ( Cp* = pentamethylcyclopentadienyl, dppe = 1,2-diphenylphosphinoethane)
framework (1) was successfully prepared and characterized by 1H NMR, elemental analysis and single
crystal X-ray diffraction. The redox behavior of complex 1 was investigated by voltammetric methods and
anodic spectroelectrochemistry in the UV-vis-NIR-IR region and compared with reference complexes
including 2-ferrocenylbenzo[b]thiophene (2) and the 2-ethynylpyridine derivative of 1. The spin density
distribution along the linear molecular backbone in stable 1
+
was analyzed by DFT (BLYP35) and TDDFT
calculations of a truncated model complex. The combined experimental and theoretical results have
revealed an important role of the ethynylene linker in determining the redox properties of this family of
complexes and a sizable participation the 2-ethynylbenzo[b]thiophene framework in the largely iron-based
anodic electron transfe
Cerebrospinal fluid neurofilament dynamic profiles predict cognitive progression in individuals with de novo Parkinson’s disease
BackgroundNeurofilament light chain protein (NfL) in cerebrospinal fluid (CSF) reflects the severity of neurodegeneration, with its altered concentrations discovered in Parkinson’s disease (PD) and Parkinson’s disease dementia (PD-D).ObjectiveTo determine whether CSF NfL, a promising biomarker of neuronal/axonal damage, can be used to monitor cognitive progression in de novo Parkinson’s disease and predict future cognitive decline.MethodsA total of 259 people were recruited in this study, including 85 healthy controls (HC) and 174 neonatal PD patients from the Parkinson’s Progression Markers Initiative (PPMI). Multiple linear regression and linear mixed effects models were used to examine the associations of baseline/longitudinal CSF NfL with cognitive decline and other CSF biomarkers. Kaplan–Meier analysis and log-rank test were used to compare the cumulative probability risk of cognition progression during the follow-up. Multivariate cox regression was used to detect cognitive progression in de novo PD.ResultsWe found PD patients with mild cognitive impairment (PD-MCI) was higher than with normal cognition (PD-NC) in terms of CSF NfL baseline levels (p = 0.003) and longitudinal increase rate (p = 0.034). Both baseline CSF NfL and its rate of change predicted measurable cognitive decline in de novo PD (MoCA, β = −0.010, p = 0.011; β = −0.0002, p < 0.001, respectively). The predictive effects in de novo PD patients aged >65, male, ill-educated (<13 years) and without carrying Apolipoprotein E ε4 (APOE ε4) seemed to be more obvious and reflected in more domains investigated. We also observed that CSF NfL levels predicted progression in de novo PD patients with different cognitive diagnosis and amyloid status. After an average follow-up of 6.66 ± 2.54 years, higher concentration above the median of baseline CSF NfL was associated with a future high risk of PD with dementia (adjusted HR 2.82, 95% CI: 1.11–7.20, p = 0.030).ConclusionOur results indicated that CSF NfL is a promising prognostic predictor of PD, and its concentration and dynamics can monitor the severity and progression of cognitive decline in de novo PD patients
Leveraging opportunity of low carbon transition by super-emitter cities in China
Funding Information: The work was supported by the National Natural Science Foundation of China (7224100119), the National Key Research and Development Program of China (2022YFE0208700 and 2022YFE0208500), and the Norwegian Research Council (287690/F20). We appreciate the suggestions from Prof. Edgar Hertwich of Norweign University of Science andTechnology. Publisher Copyright: © 2023 Science China PressChinese cities are core in the national carbon mitigation and largely affect global decarbonisation initiatives, yet disparities between cities challenge country-wide progress. Low-carbon transition should preferably lead to a convergence of both equity and mitigation targets among cities. Inter-city supply chains that link the production and consumption of cities are a factor in shaping inequality and mitigation but less considered aggregately. Here, we modelled supply chains of 309 Chinese cities for 2012 to quantify carbon footprint inequality, as well as explored a leverage opportunity to achieve an inclusive low-carbon transition. We revealed significant carbon inequalities: the 10 richest cities in China have per capita carbon footprints comparable to the US level, while half of the Chinese cities sit below the global average. Inter-city supply chains in China, which are associated with 80% of carbon emissions, imply substantial carbon leakage risks and also contribute to socioeconomic disparities. However, the significant carbon inequality implies a leveraging opportunity that substantial mitigation can be achieved by 32 super-emitting cities. If the super-emitting cities adopt their differentiated mitigation pathway based on affluence, industrial structure, and role of supply chains, up to 1.4 Gt carbon quota can be created, raising 30% of the projected carbon quota to carbon peak. The additional carbon quota allows the average living standard of the other 60% of Chinese people to reach an upper-middle-income level, highlighting collaborative mechanism at the city level has a great potential to lead to a convergence of both equity and mitigation targets.Peer reviewe
Leveraging opportunity of low carbon transition by super-emitter cities in China
Chinese cities are core in the national carbon mitigation and largely affect global decarbonisation initiatives, yet disparities between cities challenge country-wide progress. Low-carbon transition should preferably lead to a convergence of both equity and mitigation targets among cities. Inter-city supply chains that link the production and consumption of cities are a factor in shaping inequality and mitigation but less considered aggregately. Here, we modelled supply chains of 309 Chinese cities for 2012 to quantify carbon footprint inequality, as well as explored a leverage opportunity to achieve an inclusive low-carbon transition. We revealed significant carbon inequalities: the 10 richest cities in China have per capita carbon footprints comparable to the US level, while half of the Chinese cities sit below the global average. Inter-city supply chains in China, which are associated with 80% of carbon emissions, imply substantial carbon leakage risks and also contribute to socioeconomic disparities. However, the significant carbon inequality implies a leveraging opportunity that substantial mitigation can be achieved by 32 super-emitting cities. If the super-emitting cities adopt their differentiated mitigation pathway based on affluence, industrial structure, and role of supply chains, up to 1.4 Gt carbon quota can be created, raising 30% of the projected carbon quota to carbon peak. The additional carbon quota allows the average living standard of the other 60% of Chinese people to reach an upper-middle-income level, highlighting collaborative mechanism at the city level has a great potential to lead to a convergence of both equity and mitigation targets
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A conjugated diosma-octacyclic complex and its mixed-valence singly reduced state
In this work two dicationic diosma-octacyclic complexes have successfully been synthesized and fully characterized. One of them, with aromatic osmapentalene termini linked by the non-aromatic osmafuran moiety to the rigid naphthalenediolate bridge, represents the first example of a fused, fully conjugated dimetalla-octacyclic complex. A reference complex with more flexible biphenolate in the bridging position was also prepared. Their redox and electronic properties were investigated by combined methods of cyclic voltammetry and UV-vis-NIR–IR spectroelectrochemistry, supported by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. The rigid octacyclic complex forms a stable singly reduced mixed-valence species with the spin density localized at one of the osmapentalene termini
Periodontitis Exacerbates and Promotes the Progression of Chronic Kidney Disease Through Oral Flora, Cytokines, and Oxidative Stress
Periodontitis is a type of systemic immune inflammation that is caused by the complex infection of a variety of microorganisms in the subgingival plaque and the imbalance of the microbial ecological environment in the mouth. Periodontitis and chronic kidney disease (CKD) share many risk factors, such as obesity, smoking, and age. A growing body of data supports a strong correlation between periodontitis and kidney disease. Evidence supports the role of periodontal inflammation and elevated serum inflammatory mediators in renal atherosclerosis, renal deterioration, and end-stage renal disease (ESRD) development. Periodontitis is a risk factor for kidney disease. However, to our knowledge, there are few studies detailing the possible link between periodontitis and CKD. This review summarizes the possible mechanisms underlying periodontitis and CKD. More importantly, it highlights novel and potential pathogenic factors for CKD, including bacteria, pro-inflammatory mediators and oxidative stress. However, most research on the relationship between periodontitis and systemic disease has not determined causality, and these diseases are largely linked by bidirectional associations. Future research will focus on exploring these links to contribute to new treatments for CKD
Leveraging opportunity of low carbon transition by super-emitter cities in China
Chinese cities are core in the national carbon mitigation and largely affect global decarbonisation initiatives, yet disparities between cities challenge country-wide progress. Low-carbon transition should preferably lead to a convergence of both equity and mitigation targets among cities. Inter-city supply chains that link the production and consumption of cities are a factor in shaping inequality and mitigation but less considered aggregately. Here, we modelled supply chains of 309 Chinese cities for 2012 to quantify carbon footprint inequality, as well as explored a leverage opportunity to achieve an inclusive low-carbon transition. We revealed significant carbon inequalities: the 10 richest cities in China have per capita carbon footprints comparable to the US level, while half of the Chinese cities sit below the global average. Inter-city supply chains in China, which are associated with 80% of carbon emissions, imply substantial carbon leakage risks and also contribute to socioeconomic disparities. However, the significant carbon inequality implies a leveraging opportunity that substantial mitigation can be achieved by 32 super-emitting cities. If the super-emitting cities adopt their differentiated mitigation pathway based on affluence, industrial structure, and role of supply chains, up to 1.4 Gt carbon quota can be created, raising 30% of the projected carbon quota to carbon peak. The additional carbon quota allows the average living standard of the other 60% of Chinese people to reach an upper-middle-income level, highlighting collaborative mechanism at the city level has a great potential to lead to a convergence of both equity and mitigation targets
Potential interaction between the oral microbiota and COVID-19: a meta-analysis and bioinformatics prediction
ObjectivesThe purpose of this study was to evaluate available evidence on the association between the human oral microbiota and coronavirus disease 2019 (COVID-19) and summarize relevant data obtained during the pandemic.MethodsWe searched EMBASE, PubMed, and the Cochrane Library for human studies published up to October 2022. The main outcomes of the study were the differences in the diversity (α and β) and composition of the oral microbiota at the phylum and genus levels between patients with laboratory-confirmed SARS-CoV-2 infection (CPs) and healthy controls (HCs). We used the Human Protein Atlas (HPA), Gene Expression Profiling Interactive Analysis (GEPIA) database, Protein−protein interaction (PPI) network (STRING) and Gene enrichment analysis (Metascape) to evaluate the expression of dipeptidyl peptidase 4 (DPP4) (which is the cell receptor of SARS CoV-2) in oral tissues and evaluate its correlation with viral genes or changes in the oral microbiota.ResultsOut of 706 studies, a meta-analysis of 9 studies revealed a significantly lower alpha diversity (Shannon index) in CPs than in HCs (standardized mean difference (SMD): -0.53, 95% confidence intervals (95% CI): -0.97 to -0.09). Subgroup meta-analysis revealed a significantly lower alpha diversity (Shannon index) in older than younger individuals (SMD: -0.54, 95% CI: -0.86 to -0.23/SMD: -0.52, 95% CI: -1.18 to 0.14). At the genus level, the most significant changes were in Streptococcus and Neisseria, which had abundances that were significantly higher and lower in CPs than in HCs based on data obtained from six out of eleven and five out of eleven studies, respectively. DPP4 mRNA expression in the oral salivary gland was significantly lower in elderly individuals than in young individuals. Spearman correlation analysis showed that DPP4 expression was negatively correlated with the expression of viral genes. Gene enrichment analysis showed that DPP4-associated proteins were mainly enriched in biological processes, such as regulation of receptor-mediated endocytosis of viruses by host cells and bacterial invasion of epithelial cells.ConclusionThe oral microbial composition in COVID-19 patients was significantly different from that in healthy individuals, especially among elderly individuals. DPP4 may be related to viral infection and dysbiosis of the oral microbiome in elderly individuals
Observation of the electromagnetic doubly OZI-suppressed decay
Using a sample of billion events accumulated with the BESIII
detector at the BEPCII collider, we report the observation of the decay , which is the first evidence for a doubly
Okubo-Zweig-Iizuka suppressed electromagnetic decay. A clear structure
is observed in the mass spectrum around 1.02 GeV/, which can
be attributed to interference between and
decays. Due to this interference, two
possible solutions are found. The corresponding measured values of the
branching fraction of are and .Comment: 7 pages, 4 figures, published in Phys. Rev.
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