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By using ultrasound strain rate (SR) imaging to evaluate the left atrial (LA) reservoir and pump function after catheter ablation (CA) with persistent atrial fibrillation (PAF).A total of 45 patients with PAF underwent echocardiography examination before and after ablation as well as during 6 months of follow-up. Peak SR was measured at each LA segment (septal, lateral, anterior, inferior and posterior) during systole (LAs) and late diastole (LAa).During 6 months after CA, 30 patients were free of atrial fibrillation recurrence (AFR). left atrial area index (LAAI), left atrial maximum volume index (LAVImax), and E/Ea were obviously higher in patients with before CA, left atrial ejection fraction (LAEF), SR-LAs were lower than in normal cases, the SR-LAa was disappeared. Shortly after ablation, SR-LAa was recovered, and SR-LAs was reduced compared to those at baseline. At midterm follow-up, LAEF and SR-LAs were still lower than the control group, and LAAI and LAVImax were higher. SR-LAa was recovered slowly over time, but still lower.LA reservoir function was seriously damaged and LA pump function disappeared in patients with PAF. LA reservoir function impairment appeared shortly after ablation, it showed improvement at midterm follow-up, but some degree of damage to the LA reservoir and pump function was still present. Speckle tracking imaging is a feasible technique for the assessment of LA function in patients with PAF, which is a potentially valuable clinical tool to assist in the early detection of atrial remodelling and reverse remodelling.

Objective Noninvasive myocardial work (MW) is a new technology which is based on strain after considering the load influence on myocardial deformation. We aimed to investigate the feasibility of quantitatively assessing left ventricular myocardial work (LVMW) in patients with systemic lupus erythematosus (SLE) using a left ventricular pressure-strain loop (LVPSL). Methods 76 patients with SLE were included in the study (A), further divided into two subgroups according to the presence of lupus nephritis (LN). Global longitudinal strain (GLS), peak strain dispersion (PSD), global myocardial work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) were obtained. Results 1: Patients with SLE demonstrated a significantly reduced GWE and GLS compared with control group, GWW and PSD were increased, above changes were more pronounced in patients with LN. There was no significant difference in GWI and GCW. 2: Receiver operating characteristic (ROC) analysis demonstrated that GWE was the most powerful tool for detecting myocardial insufficiency early in SLE patients, and the area under the curve (AUC) was 0.804, and was superior to GLS (AUC = 0.707). GWE remains the best indicator of subclinical myocardial injury in patients with LN. The AUC was 0.910, and the best cutoff point was 96.5% (sensitivity 83.3%, specificity 73.3%). Conclusions LVPSL can be used to noninvasively assess changes in MW in patients with SLE. Noninvasive GWE is a more sensitive index than GLS to detect subclinical myocardial injury early in SLE patients. This is a potential valuable clinical tool to assist in the early-find myocardial damage.

A hybrid perovskite with dielectric, SHG, and ferroelectric triple transitions was tailored into highly-oriented films using PVDF matrix-assisted in situ growth.

Both ferroelectric and switchable dielectric behaviors are of great academic value and practical significance, but they usually exist alone. If combine the two properties into one compound, it will be more valuable in practical application. In this paper, quasi-spherical (2-bromoethyl) trimethylammonium cation was used to match with [CdBr4 ]2- anion, and a new organic-inorganic hybrid compound ([BrCH2 CH2 N(CH3 )3 ]+2 [CdBr4 ]2- , BETABCdBr) was obtained and carefully characterized. The results indicate that this compound undergoes two continuous reversible phase transition around 342 K and 390 K. It could respectively exhibit ferroelectric and switchable dielectric properties over different temperature range. This work may provide a new clue to explore new types of bifunctional phase transition smart materials to meet various application requirements.

The understanding of structure–property relationship and exploration of novel physical properties are current research topics of molecular switchable dielectric materials. In this paper, an organic...

Antimicrobial susceptibility testing (AST) plays a vital role in anti-To investigate the characteristics of heteroresistance inA total of 704 gastric biopsies were selected for 23S rRNA and gyrA gene sequencing, 470For the 699 biopsies that were positive for 23S rRNA gene, 98 (14.0%) showed a heteroresistance genotype, and a wild type (WT) combined with A2143G (86.7%) genotype was found in most samples. For the 694 biopsies that were positive for gyrA gene, 99 (14.3%) showed a heteroresistance genotype, and a WT combined with 87K (26.3%) or WT combined with 91N (23.2%) genotype was predominant. According to the E-test results, the resistance rates of heteroresistance genotype samples for clarithromycin and levofloxacin were 36.2% and 68.1%, respectively. When dividing the heteroresistance samples into different groups according to the sequencing profile peaks of the mutation position, the resistance rates were higher along with mutation peaks at the mutation position. In addition, patients infected with mutated or heteroresistant strains showed lower peptic ulcer detection rates than those infected with the WT strain (p0.05).Heteroresistance genotypes for clarithromycin and levofloxacin were not rare in

The manipulation of structures and properties is a useful method in designing new materials. In this paper, two organic–inorganic hybrid compounds [(C6H15ClNO)2CoX4] (1, X = Cl; 2, X = Br) with reversible phase transition characteristics have been successfully synthesized. Systematic characterizations including crystal structure, thermal, dielectric, semiconducting, and photoluminescence properties were performed. Replacement of Cl with Br brings about not only the variation of the space group from C2/c to P21/c but also their properties. In comparison with Cl, the large Br atom could slow down the phase transition dynamics and give a larger thermal hysteresis of ∼25 K. Consequently, different shapes of switchable dielectric transition behavior are shown between 1 and 2. In addition, compound 2 has a smaller semiconducting band gap Eg than 1 (1.60 vs 1.65 eV). The results of this study will provide positive clues to manipulate the property of organic–inorganic hybrid compounds.

Organic–inorganic hybrid metal halides with temperature-triggered responsive switchable dielectric properties have evoked great attention for their potential application in the field of optoelectronic information. Here, we present a new organic–inorganic hybrid metal halide switchable dielectric material, [(C3H5)2N(CH3)2]2SnCl6 (1), which is obtained by the reaction of diallyldimethylaminium chloride and tin(IV) chloride pentahydrate. Compound 1 exhibits excellent high-temperature switchable dielectric performance and antifatigue. Notably, 1 also exhibits multifunctionality with semiconducting and photoluminescence property. Such a Sn(IV)-based organic–inorganic hybrid with outstanding switchable dielectric, semiconducting, and photoluminescence characteristics will pave a new approach in the development of Sn(IV)-based metal halides with practical applications.

According to “quasi-spherical theory”, structural modifications of spherical organic components have been found to be useful in obtaining ferroelectric or switchable dielectric organic–inorganic hybrid compounds, but how to tailor the spherical organic components is still unclear. In the current work, a prototype spherical tetramethylammonium cation was modified by replacing one of its H atoms with a CH2Br group, rather than with the widely studied Br atom, to obtain a new organic–inorganic hybrid compound, namely [BrCH2CH2N(CH3)3]2+[CuBr4]2− (BETABCuBr). The structure, phase transition, and dielectric and optical properties of BETABCuBr were carefully characterized. Based on these results, BETABCuBr was indicated to undergo a reversible phase transition at about 356 K, mainly due to a piston-like displacive movement of its Cu atom. The extension of the carbon chain was concluded to lead to a change of the phase transition mechanism from the typical order–disorder movement to an unusual displacive movement. We expect the results of this work to contribute to the exploration of new types of phase transition materials.

Both ferroelectric and switchable dielectric behaviors are of great academic value and practical significance, but they usually exist alone. If combine the two properties into one compound, it will be more valuable in practical application. In this paper, quasi-spherical (2-bromoethyl) trimethylammonium cation was used to match with [CdBr

A new mercury coordination polymer was successfully prepared from HgCl2 and 5-methyltetrazole (Hmtz) and characterized by elemental analysis, thermal analysis, luminescence, theoretical calculation, powder X-ray diffraction and single-crystal X-ray diffraction. Complex 1 is a three-dimensional (3D) hybrid framework constructed from 1D double mercury halide chains and mtz−, and it has an unprecedented ‘AFUQOH’ topological network. Time-dependent density functional theory (TDDFT) calculations reveal that the mechanisms of the fluorescence emission of 1 are dominantly resulted from the metal-to-ligand charge transfer (MLCT) and ligand-to-metal charge transfer (MLCT). Impressively, acentric complex 1 displays not only second harmonic generation (SHG) response but also ferroelectric behaviors.

A series of novel 4f-3d crystalline porphyrinic compounds, {[Co(TPPS)]2[Ln(Histidine)(H2O)][Ln(H3O)3]}n·nH2O (Ln = Sm (1), Eu (2), Dy (3); TPPS = 5,10,15,20-tetra(4-sulfonatophenyl)porphyrinato) with TPPS and histidine as mixed ligands, have been prepared and characterized by single-crystal X-ray diffraction technique. Complexes 1–3 are isomorphous and characteristic of a three-dimensional (3D) framework with the lanthanide ions in two kinds of coordination geometries, i.e., eightfold square antiprism and ninefold monocapped square antiprism. The porphyrin macrocycles adopt a saddle-distorted nonplanar conformation with an embedded cobalt ion binding to four pyrrole nitrogen atoms. As revealed by the photoluminescence measurement, they exhibit blue emission. Variable-temperature magnetic susceptibility reveals that complexes 1–3 are antiferromagnetic. Their FTIR, CV, DPV, and UV/vis results are also studied in detail.

Three new mercury coordination polymers, [HgCl2(Hmtz)]n (1), (2) and [Hg2(mtz)4]n (3), were successfully prepared from HgCl2 and 5-methyltetrazole (Hmtz) and characterized by elemental analysis, thermal analysis, luminescence, theoretical calculation, powder X-ray diffraction and single-crystal X-ray diffraction. The results reveal that 1 and 2 are isomers resulted from different one dimensional (1D) mercury halides chains, and they are all 3D supramolecular structures. Complex 3 possesses a 2-fold interpenetrated diamondoid network with intersecting channels. Time-dependent density functional theory (TDDFT) calculations reveal that the mechanisms of the fluorescence emission are dominantly resulted from the ligand-to-metal charge transfer (LLCT) and partial ligand-to-ligand charge transfer (LLCT) for 1 and 2, but ligand-to-metal charge transfer (LMCT) for 3, which is in good agreement with their different fluorescence spectra and crystal structures. Optical absorption spectra indicate that complexes 1–3 have wide optical band-gaps and can be probably used as wide optical band-gap semiconductor materials.

A new inorganic-organic hybrid complex based on well-defined Keggin-type polyoxometalates and copper-lutidine assemblies, namely, [Cu3(3,5-Lutidine)6(PW12O40)]n (1), has been obtained under hydrothermal conditions and characterized by elemental analysis and single crystal X-ray diffraction. The X-ray diffraction analysis reveals that compound 1 is three-dimensional (3D) supramolecular structure with ‘sql’ topological 2D layer. The photocatalytic experiments indicate that 1 exhibit good catalytic activity for photodegradation of Rhodamine B (RhB) with UV irradiation. The thermal stabilities and fluorescent properties of this complex have also been studied.

Two new Pb(II) coordination polymers, namely, [Pb(Hpydc)2]n (1), [Pb(Hpydc)2(H2O)]n·2n(H2O) (2) (H2pydc ​= ​2,5-pyridinedicarboxylic acid) have been prepared by the reaction of PbCl2 with pyridinedicarboxylic acid and fully characterized. Compound 1 contains ‘sql’ topological layers built from one-dimensional (1D) Pb-carboxylate infinite chains, and the layers are further packed into a 3D architecture by strong hydrogen bonds interactions. Compound 2 consists of 1D infinite chains containing Pb-dimers. The 3D supramolecular Pb(II) coordination complex of 2 is created by π – π interactions between the pyridine rings of the Hpydc ligands. In addition, solid-state properties of thermal stability and fluorescence for these crystalline materials are also presented. Time-dependent density functional theory (TDDFT) calculations reveal that the mechanism of the fluorescence emissions are dominantly resulted from the ligand-to-metal charge transfer (LMCT) and partial the intraligand π→π∗ and/or n→π∗ transitions for 1 and 2, which are in good agreement with their fluorescence spectra and crystal structure.

A new multifunctional mixed-valence copper(I/II) coordination polymer, {[CuCN][Cu(isonic)2]}n (1) (Hisonic = isonicotinic acid), was synthesized by treating isonicotinic acid and 5-amino-tetrazolate (Hatz = 5-amino-tetrazolate) with copper(II) salts under hydrothermal conditions, and characterized by elemental analysis, infrared spectroscopy, and single crystal X-ray diffraction, respectively. The X-ray diffraction analysis reveals that compound exhibit noncentrosymmetric polar packing arrangement. It is three-dimensional (3D) framework with (3,5)-connected ‘seh-3’ topological network constructed from metal organic framework {[Cu(isonic)2]}n and the inorganic linear chain{Cu(CN)}n subunits. A remarkable feature of 1 is the rhombic open channels that are occupied by a linear chain of {Cu(CN)}n. Impressively compound 1 displays not only a second harmonic generation (SHG) response, but also a ferroelectric behavior and magnetic properties.

We report a new flexible switchable dielectric composite film toward practical application in devices based on β-phase-dominated PVDF modified with single-protonated 1,4-diazabicyclo[2.2.2]octane fluoborate (DabcoHBF4). Our study suggested that incorporating polar molecular filler (DabcoHBF4) into β-phase-dominated PVDF is an effective method to fabricate switchable dielectric thin film, which could avoid sophisticated operation in cultivating bulk crystals of molecular materials. The composite film with 40% of DabcoHBF4 (0.40BF) could exhibit large dielectric change between high and low dielectric states comparable to that of pure DabcoHBF4 at phase-transition temperature. We postulated that the excellent switchable dielectric property of 0.40BF was attributed to the induced orientation alignment of β-phase-dominated PVDF and dielectric confinement effect.

The objective of this study was to investigate five nutrient factors of the forest topsoil (0–20 cm), including pH, soil organic matter (SOM), total nitrogen (STN), available phosphorus (AP), and available potassium (AK). This study adopted the revised Nemerow index method to conduct a comprehensive quantitative evaluation on the soil nutrition contents, and using geostatistical method to address the spatial variability of soil properties in hilly and mountainous regions, southern China. Data were analyzed both statistically and geostatistically on the basis of semivariogram. Our results indicate that the soil is generally acidic, containing rich SOM and STN, but lacks AP and AK. Most of the sub-indexes of fertility were at grade III, showing a middle level. According to the coefficient of variations (CV), the five soil nutrient factors can be ranked in decreasing order as follows: AP > SOM > AK > STN > pH. There were differences between the sub-indexes of fertility, which could be ranked as follows: PSOM > PAK > PSTN > PpH > PAP. The semi-variation functions for the five soil nutrient factors studied here show some spatial structure features, over a range of 23–274 km. All nutrient factors had different nugget-to-sill ratios in each region, which varied from 10 to 50%, suggesting a strong or medium correlation. Thus, it can be concluded that the nutrient spatial distribution of the study area was the result of the combined action of structural factors and random factors, and the factors affecting the soil nutrients of the research area are highly complex. We will develop more targeted research plans about soil nutrients of study area in the next time.

Thin-walled workpieces are widely used in the aerospace manufacturing industry in order to reduce the weight of structure and improve working efficiency. However, vibration is easy to occur in machining of thin-walled structures due to its low stiffness. Machining vibration will result in lower machining accuracy as well as machining efficiency. In order to reduce the machining vibrations of thin-wall workpieces, commonly used method is to select proper machining parameters according to the chatter stability lobes, which is generated according to the machining system parameters. However, this method requires exact system parameters to be determined, which are always changing in the machining process. In this paper, a special designed fixture with damping materials for the thin-walled workpiece is presented based on the machining vibration control theory, and analysis of the effect of vibration suppressing is obtained through the contrast of vibration tests of milling the thin-walled workpiece on the damping clamp. The damping material is used to consume vibration energy and provide support for thin-walled structure. Machining test was carried out for thin-walled structure machining to validate the effectiveness of the proposed method.

Four new mercury coordination polymers were successfully synthesized under solvothermal conditions and characterized by elemental analysis, IR spectroscopy, thermal analysis, powder X-ray diffraction and single-crystal X-ray diffraction. In these complexes, the chemical valence of mercury is +2, except for complex 1 which is +1. 1 contains [Hg2]2+ metal–metal bonded cores which are bounded by atz− (Hatz = 5-amino-tetrazolate) ligands and features a two-dimensional (2D) uninodal 3-connected ‘hcb’ network. 2 exhibits a trinodal 3D (3,6)-connected ‘apo/alpha-PbO2’ topological net in which 2D [HgCl]nn+ inorganic cation layers are pillared by atz− ligands. In 3, the 2D [HgCl]nn+ cation layers are interconnected by atz− ligands, affording a trinodal 3D (3,6)-connected ‘flu/fluorite’ topological net. 4 is a 3D pillared-layer metal–organic framework based on mixed atz− and isonicotinic ligands, showing a binodal (4,6)-connected ‘fsc’ coordination network. In this work, 1 and 4 were synthesized from an in situ generated tetrazolate ligand, while 2 and 3 were prepared from a commercially available tetrazolate ligand. These results indicate that the final structures of the target complexes will highly depend on the synthetic conditions as well as the preparation methods. Moreover, the photoluminescence properties of these complexes were investigated. Impressively, the non-centrosymmetric complex 3 displays not only a second harmonic generation (SHG) response but also a ferroelectric behavior.

A ferroelectric compound diisopropylammonium bromide (DIPAB) was dispersed into poly(vinylidene fluoride) (PVDF) matrix to form DIPAB/PVDF composite films. The composite film with different content of DIPAB was characterized by IR, XRD, DSC and SEM. The results indicated that soluble DIPAB could be homogeneously dispersed within PVDF matrix to form almost pure β-phase PVDF composite films without obvious agglomeration, and the crystallinity of PVDF polymer increased with increasing content of DIPAB inclusion. DIPAB/PVDF composite films exhibit very high dielectric constants and relatively low dielectric loss. Both dielectric constants and dielectric loss are frequency dependent and increased with increasing DIPAB content. DIPAB/PVDF composite films also exhibit enhanced ferroelectric properties. Incorporating DIPAB into PVDF is a useful way to improve the dielectric and ferroelectric property of PVDF composite films.

Three novel Ln–Hg complexes [Ln(H2O)2(μ-IA)3Hg3Br6]n (Ln = Pr (1), Nd (2), and Er (3); HIA is isonicotinic acid) are synthesized and characterized. They feature three-dimensional (3-D) motifs. Solid-state UV/vis diffuse reflectance spectroscopy found that their band gaps are 4.91, 4.59, and 2.68 eV. It is found that lanthanide ions could adjust the band structures of semiconductors. Their photoluminescence comes from their characteristic emissions of 1D2 → 3H4 of Pr3+, 7F7/2 → 4S3/2 and 4F3/2 → 4I9/2 of Nd3+, and 4I15/2 → 4F7/2 and 4I15/2 → 4S3/2 of Er3+. The CIE chromaticity coordinate is (x = 0.5726, y = 0.4206), (x = 0.7268, y = 0.2732), and (x = 0.2923, y = 0.4317). Their magnetization susceptibility totally obeys the Curie–Weiss equation with antiferromagnetic performances.

A novel tetranuclear lead-edta compound [Pb4(edta)(H2O)2(N3)4]n (1) (H4edta = ethylenediaminetetraacetic acid) has been synthesized by the reaction of PbF2 with H4edta and NaN3 mixed-ligands under hydrothermal conditions, and was characterized by elemental analysis, thermal analysis, luminescence, powder X-ray diffraction and single-crystal X-ray diffraction. The results of X-ray crystallographic analysis reveal that compound 1 is the first 3D Pb(II)-edta coordination polymer with a high ratio of lead. Remarkably, the edta4− ligand uses all its 10 donor atoms (8O ​+ ​2 ​N) coordinated to Pb(II) ions and formed a 2D layer. The 2D layers are further linked to a complex 3D coordination polymer by the inorganic chain [Pb5(N3)10]n. Time-dependent density functional theory (TDDFT) calculations reveal that the mechanism of the fluorescence emission is dominantly resulted from the ligand-to-metal charge transfer (LMCT) for 1, which is in good agreement with its fluorescence spectra and crystal structure. Optical absorption spectra indicate that 1 has wide optical band-gaps and can be probably used as wide optical band-gap semiconductor material.