4f/5d Hybridization Induced Single-Electron Delocalization in an Azide-Bridged Dicerium Complex.

Dilanthanide complexes with one-electron delocalization are important targets for understanding the specific 4f/5d-bonding feature in lanthanide chemistry. Here, we report an isolable azide-bridged dicerium complex 3 [{(TrapenTMS)Ce}2(µ-N3)]• [Trapen = tris (2-aminobenzyl)amine; TMS = SiMe3], which is synthesized by the reaction of tripodal ligand-supported (TrapenTMS)CeIVCl complex 2 with NaN3. The structure and bonding nature of 3 are fully characterized by X-ray crystal diffraction analysis, electron paramagnetic resonance (EPR), magnetic measurement, cyclic voltammetry, X-ray absorption spectroscopy, and quantum-theoretical studies. Complex 3 presents a trans-bent central Ce-N3-Ce unit with a single electron of two mixed-valent Ce atoms. The unique low-temperature (2 K) anisotropic EPR signals [g = 1.135, 2.003, and 3.034] of 3 indicate that its spin density is distributed on the central Ce-N3-Ce unit with marked electron delocalization. Quantum chemical analyses show strong 4f/5d orbital mixing in the singly occupied molecular orbital of 3, which allows for the unpaired electron to extend throughout the cerium-azide-cerium unit via a multicentered one-electron (Ce-N3-Ce) interaction. This work extends the family of mixed-valent dilanthanide complexes and provides a paradigm for understanding the bonding motif of ligand-bridged dilanthanide complexes.

Association between gout and the risk of osteoporosis and fractures: a meta-analysis.

OBJECTIVE: The relationship between gout and osteoporosis is poorly clarified, and the association between gout and fractures incidence remains controversial. Hence, in the present study, we aimed to comprehensively evaluate the available literature to elucidate whether gout is associated with an increased risk of both osteoporosis and fractures. MATERIALS AND METHODS: We conducted an exhaustive search of pertinent literature published until 20 March 2023, in well-recognized databases, namely Medline, Embase and Cochrane Library, focusing on examining the association between gout and the risk of osteoporosis or fracture. Meta-analysis was performed to aggregate the relative risks (RR) using random- or fixed-effects models. Sensitivity analyses were conducted iteratively, whereby each study was removed sequentially to gauge its impact on the overall outcome. Publication bias was assessed using Egger's and Begg's tests. This study was registered with PROSPERO (registry number: CRD42022376822). RESULTS: Herein, we included 10 observational studies comprising a total of 1,606,095 participants. An independent population sample of four studies validated the significant association between gout and osteoporosis (RR = 1.25, 95% confidence interval [CI] 1.05-1.48), with the results demonstrating robustness. However, our analysis did not detect any association between gout and fracture risk when compared with the control group (RR = 1.09, 95%CI 0.99-1.19), along with high heterogeneity (p for heterogeneity = 0.000; I2 = 79.7%). Further subgroup analysis revealed that gout is positively associated with fracture risk in the Chinese population (RR = 1.17, 95%CI 1.14-1.21), with no evidence of heterogeneity (p for heterogeneity = 0.420; I2 = 0.00%). CONCLUSION: Our meticulous evaluation of the available literature indicates that gout has no discernible impact on fracture incidence, although it is positively associated with an enhanced risk of osteoporosis. Therefore, it is imperative to prioritize preventive measures to prevent osteoporotic complications in individuals diagnosed with gout.

Th6-Based Multicomponent Heterometallic Metal-Organic Frameworks Featuring 6,12-Connected Topology for Iodine Adsorption.

Its high coordination number and tendency to cluster make Th4+ suitable for constructing metal-organic frameworks (MOFs) with novel topologies. In this work, two novel thorium-based heterometallic MOF isomers (IHEP-17 and IHEP-18) were assembled from a Th6 cluster, a multifunctional organic ligand [4-(1H-pyrazol-4-yl)benzoic acid (HPyba)], and Cu2+/Ni2+ cations via the one-pot solvothermal synthesis strategy. The framework features a 6,12-connected new topology net and contains two kinds of supramolecular cage structures, Th36M4 and Th24M2, suitable for guest exchange. Both MOF materials can efficiently adsorb I2. X-ray photoelectron spectroscopy, Raman spectroscopy, and single-crystal X-ray diffraction indicate that the adsorbed iodine is uniformly distributed within the Th36M4 cage but not the Th24M2 cage in the form of I3-.

Association of hyperhomocysteinemia and chronic kidney disease in the general population: a systematic review and meta-analysis.

BACKGROUND: Increasing evidence shows that an elevated homocysteine(Hcy) level is associated with an increased risk of chronic kidney disease (CKD). This study systematically evaluated the correlation between homocysteine level and the incidence of CKD reported in cohort and cross-sectional studies. METHODS: We searched electronic databases and reference lists for relevant articles. 4 cohort studies and 7 cross-sectional studies including 79,416 patients were analyzed in a meta-analysis. Hyperhomocysteinemia was defined as a Hcy level > 15 µmol/L, which was the criterium used in previous studies. Meta-analyses were conducted of literature searches from online databases such as PubMed, Embase, Cochrane and Scopus. Computed pooled adjusted odds ratios with corresponding 95% confidence intervals (95% CI) were used to estimate the risk of new-onset CKD according to Hcy levels in the general population. RESULTS: People with high Hcy levels were more likely to suffer from CKD than people with normal Hcy levels (pooled OR, 2.09; 95% CI, 1.72-2.55). This positive relationship persisted across different study types such as cohort studies (summary OR, 2.2; 95% CI, 1.55-3.13) and cross-sectional studies (summary OR, 2.07; 95% CI, 1.63-2.63). CONCLUSIONS: People with hyperhomocysteinemia have a higher incidence of CKD, Hyperhomocysteinemia may also be an independent risk factor for CKD in the general population.

Melatonin alleviates the heat stress-induced impairment of Sertoli cells by reprogramming glucose metabolism.

Sertoli cells (SCs) provide structural and nutritional support for developing germ cells. Normal glucose metabolism of SCs is necessary for spermatogenesis. Melatonin could alleviate the effects of heat stress on spermatogenesis. However, the influences of heat stress on glucose metabolism in SCs remain unclear, and the potential protective mechanisms of melatonin on SCs need more exploration. In this study, boar SCs were treated at 43°C for 30 min, and different concentrations of melatonin were added to protect SCs from heat stress-induced impairment. These results showed that heat stress-induced oxidative stress caused cell apoptosis, inhibited the pentose phosphate pathway, and decreased the ATP content. Furthermore, heat stress increased the expressions of glucose intake- and glycolytic-related enzymes, which enhanced the glycolysis activity to compensate for the energy deficit. Melatonin relieved heat stress-induced oxidative stress and apoptosis by activating the Kelch-like ECH-associated protein 1 (KEAP1)/NF-E2-related factor 2 signaling pathway to increase the capacity of antioxidants. In addition, melatonin enhanced heat-shock protein 90 (HSP90) expression through melatonin receptor 1B (MTNR1B), thereby stabilizing hypoxia-inducible factor-1α (HIF-1α). Activation of the HIF-1α signaling pathway enhanced glycolysis, promoted the pentose phosphate pathway, and increased cell viability. Our results suggest that melatonin reprograms glucose metabolism in SCs through the MTNR1B-HSP90-HIF-1α axis and provides a theoretical basis for preventing heat stress injury.

Modular Assembly of Isostructural Mixed-Ligand Uranyl Coordination Polymers Based on a Patterning Strategy.

Controlling the orderly assembly of molecular building blocks for the formation of the desired architectural, chemical, and physical properties of the resulting solid-state materials remains a long-term goal and deserves to be examined. In this work, we propose a patterning strategy for modular assembly and structural regulation of mixed-ligand uranyl coordination polymers (CPs) through the combination of couples of organic ligands with complementary molecular geometry and well-matched coordination modes. By using a 5-(p-tolyldiazenyl)isophthalic acid ligand (H2ptdi) with different rigid linear bicarboxylic acid linkers to construct a well-defined ladder-like pattern, five novel isostructural uranyl coordination polymers, [(UO)2(ptdi)(bdc)0.5](dma) (1), [(UO)2(ptdi)(bpdc)0.5](dma) (2), [(UO)2(ptdi)(tpdc)0.5](dma) (3), [(UO)2(ptdi)(ndc)0.5](dma) (4), and [(UO)2(ptdi) (pdc)0.5](dma) (5) {H2bdc, 1,4-dicarboxybenzene; H2bpdc, 4,4'-biphenyldicarboxylic acid; H2tpdc, terphenyl-4,4″-dicarboxylic acid; H2ndc, 2,6-naphthalenedicarboxylic acid; H2pdc, 1,6-pyrenedicarboxylic acid; [dma]+, [(CH3)2NH2]+}, were successfully synthesized. Structural analysis reveals that 1-5 have similar ladder-like units but different sizes of one-dimensional nanochannels and interlayer spacing due to the different lengths and widths of the linkers. Because of the changes in interlayer spacing of these isostructural cationic frameworks, differences in the performance of Eu3+ ion exchange with [dma]+ are observed. Moreover, those compounds with high phase purity have been further characterized by thermogravimetric analysis, infrared spectroscopy, and luminescence spectroscopy, element analysis, PXRD and UV spectroscopy. Among them, compound 3 with strong fluorescence can selectively detect Fe3+ over several competing metal cations in aqueous solution. This work not only provides a feasible patterning method for effectively regulating the modular synthesis of functional coordination polymers but also enriches the library of uranyl-based coordination polymers with intriguing structures and functionality.

Coordination-Adaptive Polydentate Pseudorotaxane Ligand for Capturing Multiple Uranyl Species.

The propensity of uranyl for hydrolysis in aqueous environments prevents precise control of uranyl species in the scenarios of on-demand separation and tailored synthesis. Herein, using cucurbit[7]uril (CB[7]) as the macrocyclic molecule and 4,4'-bipyridine-N,N'-dioxide (DPO) as the string molecule, we propose a new kind of multidentate pseudorotaxane ligand, DPO@CB[7] for capturing uranyl species at different pH's. With the aprotic nature of DPO for metal coordination, the coordination ability of the DPO@CB[7] ligand is less affected by pH and can work in a wide range of pH's. Furthermore, by adaptive uranyl coordination, this aprotic pseudorotaxane ligand achieves effective recognition for different uranyl species ranging from monomeric to tetrameric originating from hydrolysis at varying pH's, and four novel uranyl-rotaxane compounds (URC1-4) are successfully obtained. Single-crystal X-ray diffraction analysis reveals that the DPO@CB[7] ligand coordinates with uranyl centers from monomeric to tetrameric in four different modes, as a result of structural flexibility of the DPO@CB[7] pseudorotaxane ligand. A detailed discussion for conformation flexibility of the DPO@CB[7] ligand has been conducted on the position changes of the DPO ligand trapped in the CB[7], which thus reveals good adaptivity of DPO@CB[7] that is noncovalently bonded as a supramolecular motif. In addition, characterization of the physicochemical properties of URC1 and URC2 with high phase purity, including powder X-ray diffraction (PXRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA), and luminescence properties, are also provided. This work provides a good case of an adaptive pseudorotaxane ligand for the recognition and capture of different uranyl species and will bring valuable hints to the design of multifunctional supramolecular ligands for actinide separation in the future.

Mixed-Ligand Uranyl Squarate Coordination Polymers: Structure Regulation and Redox Activity.

The electron-rich squarate ion (C4O42-, SA2-) possesses electronic delocalization over the entire molecule and good redox activity, and the functionalization of metal-organic complexes with the SA2- group is desirable. In this work, a mixed-ligand method is used to construct novel uranyl squarate coordination polymers utilizing 4,4'-bipyridine (bpy), 4,4'-bipyridine-N,N'-dioxide (bpydo), 1,10-phenanthroline (phen), 4,4'-vinylenedipyridine (vidpy), and in situ formed oxalate (OA2-) as ancillary ligands. Seven mixed-ligand uranyl compounds, [(UO2)(OH)(SA)](Hbpy) (1), [(UO2)(H2O)(SA)2](H2bpy) (2), (UO2)(H2O)(SA)(bpydo)·2H2O (3), (UO2)(H2O)(SA)(phen)·H2O (4), (UO2)(OH)(SA)0.5(phen)·H2O (5), [(UO2)(SA)(OA)0.5](Hphen) (6), and [(UO2)(SA)(OA)0.5](Hvidpy) (7), with varying crystal structures were synthesized under hydrothermal conditions. Compound 1, together with bpy molecules filling in the interlayer space as template agents, has a two-dimensional (2D) network structure, while 2 gives a one-dimensional (1D) chain based on mononuclear uranium units. Compound 3 shows a neutral 2D network through the combined linkage of SA2- and bpydo. Both 4 and 5 have a similar chain-like structure due to the capping effect of phen motifs, while phen molecules in 6 act as templating agents after protonation. Similar to 6, compound 7 has a "sandwich-like" structure in which the Hvidpy motifs locate in the voids of layers of 2D uranyl-squarate networks. The redox properties of typical mixed-ligand uranyl-squarate compounds, 1, 4, and 5 with high phase purity, are characterized using cyclic voltammetry. All three of these uranyl coordination compounds show anode peaks (Ea) at 0.777, 0.804, and 0.760 V, respectively, which correspond to the oxidation process of SA2- → SA. Meanwhile, cathodic peaks (Ec) at -0.328, -0.315, and -0.323 V corresponding to the reduction process of U(VI) → U(V) are also observed. The results reveal that all three of these uranyl coordination compounds show good redox activity and, most importantly, the interplay between two different redox-active motifs of SA2- organic linker and uranyl node. This work enriches the library of redox-active uranyl compounds and provides a feasible mixed-ligand method for regulating the synthesis of functional actinide compounds.

Synthesis of Trapen Ligand-Based U(IV) and Th(IV) 2-Phosphaethynolate Complexes and Comparison of Covalency with Corresponding Ti(IV) Analogues.

The involvement of the 2-phosphaethynolate anion species with ambident nucleophilic properties serves as an essential protocol for synthesizing oxygen-bound or phosphorus-bound complexes. This work mainly describes the synthesis and characterization of U, Th, and Ti phosphaethynolate complexes featuring a preferential O-coordination fashion. Among these complexes, the first examples of a Ti(IV)-OCP complex 3A, Th(IV)-OCP complex 3B, and U(IV)-OCP complex 3C were assembled by a salt metathesis reaction between M(TrapenTMS)(Cl) (M = Ti, Th, U) and NaOCP(dioxane)2.5 and were all crystallographically characterized. The structural similarity of this series of phosphaethynolate complexes allows us to compare the bonding properties of d- and f-block elements in the corresponding compounds. The well-established density functional theory (DFT) computational method was employed to explore the electronic structures and covalency in M-O bonding, and the results showed a consistent pattern. The calculation result showed that 2-phosphaethynolate complexes exhibited the covalency trend of U-O > Th-O > Ti-O due to the involvement of 5f orbitals.

Impact of COVID-19 on emergency patients in the resuscitation room: A cross-sectional study.

OBJECTIVE: The purpose of this study was to evaluate the impact of COVID-19 outbreaks on emergency patients in a resuscitation room in Nanning, China. METHODS: A single-center cross-sectional retrospective study was conducted in the emergency department of a tertiary public hospital from January 1, 2019, to December 31, 2020, in Nanning, Guangxi, China. We collected the data of patients in the resuscitation room to investigate the number of patients accessing emergency services during the study period. Data in 2020 were compared to the data during the same period in 2019. RESULTS: The number of emergency patients in the resuscitation room during the COVID-19 pandemic has decreased in intrinsic diseases, extrinsic diseases, and pediatric cases, especially in the early stages of the pandemic. Additionally, the length of stay of emergency patients in the resuscitation room was reduced. CONCLUSIONS: The number of emergency patients in the resuscitation room during the pandemic of COVID-19 in 2020 was reduced compared to that in the same period in 2019 in Nanning, China. This situation shows a serious social problem, which should arouse the attention of the medical profession and the government.

Disentangling Noise from Images: A Flow-Based Image Denoising Neural Network.

The prevalent convolutional neural network (CNN)-based image denoising methods extract features of images to restore the clean ground truth, achieving high denoising accuracy. However, these methods may ignore the underlying distribution of clean images, inducing distortions or artifacts in denoising results. This paper proposes a new perspective to treat image denoising as a distribution learning and disentangling task. Since the noisy image distribution can be viewed as a joint distribution of clean images and noise, the denoised images can be obtained via manipulating the latent representations to the clean counterpart. This paper also provides a distribution-learning-based denoising framework. Following this framework, we present an invertible denoising network, FDN, without any assumptions on either clean or noise distributions, as well as a distribution disentanglement method. FDN learns the distribution of noisy images, which is different from the previous CNN-based discriminative mapping. Experimental results demonstrate FDN's capacity to remove synthetic additive white Gaussian noise (AWGN) on both category-specific and remote sensing images. Furthermore, the performance of FDN surpasses that of previously published methods in real image denoising with fewer parameters and faster speed.

Coagulation dysfunction is associated with severity of COVID-19: A meta-analysis.

To systematically analyze the blood coagulation features of coronavirus disease 2019 (COVID-19) patients to provide a reference for clinical practice. An electronic search in PubMed, EMbase, Web of Science, Scopus, CNKI, WanFang Data, and VIP databases to identify studies describing the blood coagulation features of COVID-19 patients from 1 January 2020 to 21 April 2020. Three reviewers independently screened literature, extracted data, and assessed the risk of bias of included studies, then, the meta-analysis was performed by using Stata 12.0 software. Thirty-four studies involving 6492 COVID-19 patients were included. Meta-analysis showed that patients with severe disease showed significantly lower platelet count (weighted mean differences [WMD]: -16.29 × 109 /L; 95% confidence interval [CI]: -25.34 to -7.23) and shorter activated partial thromboplastin time (WMD: -0.81 seconds; 95% CI: -1.94 to 0.33) but higher D-dimer levels (WMD: 0.44 µg/mL; 95% CI: 0.29-0.58), higher fibrinogen levels (WMD: 0.51 g/L; 95% CI: 0.33-0.69) and longer prothrombin time (PT; WMD: 0.65 seconds; 95% CI: 0.44-0.86). Patients who died showed significantly higher D-dimer levels (WMD: 6.58 µg/mL; 95% CI: 3.59-9.57), longer PT (WMD: 1.27 seconds; 95% CI: 0.49-2.06) and lower platelet count (WMD: -39.73 × 109 /L; 95% CI: -61.99 to -17.45) than patients who survived. Coagulation dysfunction is common in severe COVID-19 patients and it is associated with severity of COVID-19.

Knockdown of circ_0004104 Alleviates Oxidized Low-Density Lipoprotein-Induced Vascular Endothelial Cell Injury by Regulating miR-100/TNFAIP8 Axis.

ABSTRACT: Coronary artery disease (CAD) is a common cardiovascular disease, mainly due to vascular endothelial cell (VEC) injury caused by atherosclerosis. Circular RNA has been shown to be involved in the regulation of various diseases. However, the role and mechanism of circ_0004104 in CAD are still unclear. Oxidized low-density lipoprotein (ox-LDL) was used to construct the VEC injury model in vitro. The expression levels of circ_0004104 and miR-100 were measured by quantitative real-time polymerase chain reaction. The proliferation of VECs was determined using 3-(45)-dimethylthiahiazo (-z-y1)-35-di-phenytetrazoliumromide assay and 5-ethynyl-2'-deoxyuridine staining assay. VEC apoptosis rate was assessed using flow cytometry, and caspase-3 activity was measured using a Caspase-3 Assay Kit. The protein expression levels of Ki-67, cleaved-caspase3, and tumor necrosis factor-α-induced protein 8 (TNFAIP8) were detected by western blot analysis. Furthermore, enzyme-linked immunosorbent assay was performed to assess the concentrations of inflammatory cytokines. In addition, the relationship between miR-100 and circ_0004104 or TNFAIP8 was confirmed by dual-luciferase reporter assay and biotin-labeled RNA pull-down assay. Our results revealed that circ_0004104 was upregulated and miR-100 was downregulated in patients with CAD and ox-LDL-induced VECs. Ox-LDL could inhibit the proliferation and promote the apoptosis and inflammation of VECs to induce VEC injury. However, silenced circ_0004104 could alleviate VEC injury induced by ox-LDL. Moreover, we found that circ_0004104 could sponge miR-100 and a miR-100 inhibitor could reverse the inhibition effect of circ_0004104 knockdown on ox-LDL-induced VEC injury. In addition, TNFAIP8 was a target of miR-100, and miR-100 alleviated ox-LDL-induced VEC injury by targeting TNFAIP8. Our data suggested that circ_0004104 promoted ox-LDL-induced VEC injury by the miR-100/TNFAIP8 axis, indicating that circ_0004104 might be a potential biomarker for CAD treatment.

Proximity Effect in Uranyl Coordination of the Cucurbit[6]uril-Bipyridinium Pseudorotaxane Ligand for Promoting Host-Guest Synergistic Chelating.

In the present work, we proposed regulating uranyl coordination behavior of cucurbituril-bipyridinium pseudorotaxane ligand by utilizing meta-functionalized bipyridinium dicarboxylate guest. A tailored pseudorotaxane precursor involving 1,1'-(hexane-1,6-diyl)bis(3-cyanopyridin-1-ium) bromide (C6BPCN3) and cucurbit[6]uril (CB[6]) has designed and synthesized. Through in situ hydrolysis of the pseudorotaxane ligands and their coordination assembly with uranyl cations, seven new uranyl-rotaxane coordination polymers URCP1-URCP7 have been obtained under hydrothermal conditions in the presence of different anions. It is demonstrated that the variation of carboxylate groups from para- to meta-position greatly affected the coordination behaviors of the meta-functionalized pseudorotaxane linkers, which are enriched from simple guest-only binding to host-guest simultaneous coordination and synergistic chelating. This effective regulation on uranyl coordination of supramolecular pseudorotaxane can be attributed to the proximity effect, which refers to the meta-position carboxyl group being spatially closer to the portal carbonyl group of CB[6]. Moreover, by combining other regulation methods such as introducing competing counterions and modulating solution acidity, the nuclearity of the uranyl center and the coordination patterns of the pseudorotaxane ligand can be diversely tuned, which subsequently exert great influence on the final dimensionality of resultant uranyl compounds. This work presents a large diversity of uranyl-based coordination polyrotaxane compounds with fascinating mechanically interlocked components and, most importantly, provides a feasible approach to adjust and control the metal coordination behavior of the pseudorotaxane ligand that might expand the scope of application of such supramolecular ligands.

An Azobenzene-Modified Photoresponsive Thorium-Organic Framework: Monitoring and Quantitative Analysis of Reversible trans-cis Photoisomerization.

Monitoring and quantification of the photoresponsive behavior of metal-organic frameworks that respond to a light stimulus are crucial to establish a clear structure-activity relationship related to light regulation. Herein, we report the first azobenzene-modified photoresponsive thorium-organic framework (Th-Azo-MOF) with the formula [Th6O4(OH)4(H2O)6L6] (H2L = (E)-2'-p-tolyldiazenyl-1,1':4',4'-terphenyl-4,4″-dicarboxylic acid), in which the utilization of a thorium cluster as a metal node leads to one of the largest pore sizes among all the azobenzene-containing metal-organic frameworks (MOFs). The phototriggered transformation of the trans isomer to the cis isomer is monitored and characterized quantitatively by comprehensive analyses of NMR and UV spectroscopy, which reveals that the maximum isomerization ratio of cisTh-Azo-MOF in the solid state is 19.7% after irradiation for 120 min, and this isomerization is reversible and can be repeated several times without apparent performance changes. Moreover, the isomerization-related difference in the adsorption of the Rhodamine B guest is also illustrated and a possible photoregulated mechanism is proposed. This work will shed light on new explorations for constructing functionalized actinide porous materials by the elegant combination of actinide nodes with tailored organic ligands and furthermore will provide a comprehensive understanding of photoisomerization processes in MOF solids and insight into the mechanism on photoregulated cargo adsorption and release by photoactive MOFs.

Selective Separation of Am(III)/Eu(III) by the QL-DAPhen Ligand under High Acidity: Extraction, Spectroscopy, and Theoretical Calculations.

Although 1,10-phenanthroline-based ligands have recently shown vast opportunities for the separation of trivalent actinides (Ans(III)) from lanthanides (Lns(III)), the optimization and design of the extractant structure based on the phenanthroline framework remain hotspots for further improving the separation. Following the strategy of hard and soft donor atom combination, for the first time, the quinoline group was attached to the 1,10-phenanthroline skeleton, giving a lipophilic ligand, 2,9-diacyl-bis((3,4-dihydroquinoline-1((2H)-yl)-1),10-phenanthroline (QL-DAPhen)), for Am(III)/Eu(III) separation. In the presence of sodium nitrate, the ligand can effectively extract Am(III) over Eu(III) in HNO3 solution, with the separation factor (SFAm/Eu) ranging from 29 to 44. The coordination chemistry of Eu(III) with QL-DAPhen was investigated by slope analysis, NMR titration, UV-vis titration, Fourier transform infrared spectroscopy, electrospray ionization-mass spectrometry, and theoretical calculations. The experimental results unanimously confirm that the ligand forms both 1:1 and 1:2 complexes with Eu(III), and the stability constants (log ß) of each of the two complexes were obtained. Density functional theory calculations show that the Am-N bonds have more covalent characteristics than the Eu-N bonds in the complexes, which reveals the reason why the ligand preferentially bonds with Am(III). Meanwhile, the thermodynamic analysis reveals that the 1:1 complex is more thermodynamically stable than the 1:2 complex. The findings of this work have laid a solid theoretical foundation for the application of phenanthroline-based ligands in the separation of An(III) from practical systems.

CT imaging features of 4121 patients with COVID-19: A meta-analysis.

OBJECTIVE: We systematically reviewed the computed tomography (CT) imaging features of coronavirus disease 2019 (COVID-19) to provide reference for clinical practice. METHODS: Our article comprehensively searched PubMed, FMRS, EMbase, CNKI, WanFang databases, and VIP databases to collect literatures about the CT imaging features of COVID-19 from 1 January to 16 March 2020. Three reviewers independently screened literature, extracted data, and assessed the risk of bias of included studies, and then, this meta-analysis was performed by using Stata12.0 software. RESULTS: A total of 34 retrospective studies involving a total of 4121 patients with COVID-19 were included. The results of the meta-analysis showed that most patients presented bilateral lung involvement (73.8%, 95% confidence interval [CI]: 65.9%-81.1%) or multilobar involvement (67.3%, 95% CI: 54.8%-78.7%) and just little patients showed normal CT findings (8.4%). We found that the most common changes in lesion density were ground-glass opacities (68.1%, 95% CI: 56.9%-78.2%). Other changes in density included air bronchogram sign (44.7%), crazy-paving pattern (35.6%), and consolidation (32.0%). Patchy (40.3%), spider web sign (39.5%), cord-like (36.8%), and nodular (20.5%) were common lesion shapes in patients with COVID-19. Pleural thickening (27.1%) was found in some patients. Lymphadenopathy (5.4%) and pleural effusion (5.3%) were rare. CONCLUSION: The lung lesions of patients with COVID-19 were mostly bilateral lungs or multilobar involved. The most common chest CT findings were patchy and ground-glass opacities. Some patients had air bronchogram, spider web sign, and cord-like. Lymphadenopathy and pleural effusion were rare.

Clinical characteristics of 3062 COVID-19 patients: A meta-analysis.

We aimed to systematically review the clinical characteristics of coronavirus disease 2019 (COVID-19). Seven databases were searched to collect studies about the clinical characteristics of COVID-19 from January 1, 2020 to February 28, 2020. Then, meta-analysis was performed by using Stata12.0 software. A total of 38 studies involving 3062 COVID-19 patients were included. Meta-analysis showed that a higher proportion of infected patients was male (56.9%). The incidence rate of respiratory failure or acute respiratory distress syndrome was 19.5% and the fatality rate was 5.5%. Fever (80.4%), fatigue (46%), cough (63.1%), and expectoration (41.8%) were the most common clinical manifestations. Other common symptoms included muscle soreness (33%), anorexia (38.8%), chest tightness (35.7%), shortness of breath (35%), dyspnea (33.9%). Minor symptoms included nausea and vomiting (10.2%), diarrhea (12.9%), headache (15.4%), pharyngalgia (13.1%), shivering (10.9%), and abdominal pain (4.4%). The proportion of patients that was asymptomatic was 11.9%. Normal leukocyte counts (69.7%), lymphopenia (56.5%), elevated C-reactive protein levels (73.6%), elevated ESR (65.6%), and oxygenation index decreased (63.6%) were observed in most patients. About 37.2% of patients were found with elevated D-dimer, 25.9% of patients with leukopenia, along with abnormal levels of liver function (29%), and renal function (25.5%). Other findings included leukocytosis (12.6%) and elevated procalcitonin (17.5%). Only 25.8% of patients had lesions involving a single lung and 75.7% of patients had lesions involving bilateral lungs. The most commonly experienced symptoms of COVID-19 patients were fever, fatigue, cough, and expectoration. A relatively small percentage of patients were asymptomatic. Most patients showed normal leucocytes counts, lymphopenia, elevated levels of C-reactive protein and ESR. Bilateral lung involvement was common.

Risk factors of severe cases with COVID-19: a meta-analysis.

Our study aimed to systematically analyse the risk factors of coronavirus disease 2019 (COVID-19) patients with severe disease. An electronic search in eight databases to identify studies describing severe or critically ill COVID-19 patients from 1 January 2020 to 3 April 2020. In the end, we meta-analysed 40 studies involving 5872 COVID-19 patients. The average age was higher in severe COVID-19 patients (weighted mean difference; WMD = 10.69, 95%CI 7.83-13.54). Patients with severe disease showed significantly lower platelet count (WMD = -18.63, 95%CI -30.86 to -6.40) and lymphocyte count (WMD = -0.35, 95%CI -0.41 to -0.30) but higher C-reactive protein (CRP; WMD = 42.7, 95%CI 31.12-54.28), lactate dehydrogenase (LDH; WMD = 137.4, 95%CI 105.5-169.3), white blood cell count（WBC), procalcitonin（PCT）, D-dimer, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and creatinine（Cr）. Similarly, patients who died showed significantly higher WBC, D-dimer, ALT, AST and Cr but similar platelet count and LDH as patients who survived. These results indicate that older age, low platelet count, lymphopenia, elevated levels of LDH, ALT, AST, PCT, Cr and D-dimer are associated with severity of COVID-19 and thus could be used as early identification or even prediction of disease progression.

Molecular Spring-like Triple-Helix Coordination Polymers as Dual-Stress and Thermally Responsive Crystalline Metal-Organic Materials.

Elastic metal-organic materials (MOMs) capable of multiple stimuli-responsiveness based on dual-stress and thermally responsive triple-helix coordination polymers are presented. The strong metal-coordination linkage and the flexibility of organic linkers in these MOMs, rather than the 4 Šstacking interactions observed in organic crystals, causes the helical chain to act like a molecular spring and thus accounts for their macroscopic elasticity. The thermosalient effect of elastic MOMs is reported for the first time. Crystal structure analyses at different temperatures reveal that this thermoresponsiveness is achieved by adaptive regulation of the triple-helix chains by fine-tuning the opening angle of flexible V-shaped organic linkers and rotation of its lateral conjugated groups to resist possible expansion, thus demonstrating the vital role of adaptive reorganization of triple-helix metal-organic chains as a molecular spring-like motif in crystal jumping.