BACKGROUND: Coupling between left ventricle (LV) and left atrium (LA) plays a central role in the process of cardiac remodeling during aging and development of cardiac disease. The hydraulic force (HyF) is related to variation in size between LV and LA. The objectives of this study were to: (1) derive an estimate of left atrioventricular HyF using cine- Magnetic Resonance Imaging (MRI) in healthy subjects with a wide age range, and (2) study its relationship with age and conventional diastolic function parameters, as estimated by reference echocardiography.
METHODS: We studied 119 healthy volunteers (mean age 44 ± 17 years, 58 women) who underwent Doppler echocardiography and MRI on the same day. Conventional transmitral flow early (E) and late (A) LV filling peak velocities as well as mitral annulus diastolic longitudinal peak velocity (E\') were derived from echocardiography. MRI cine SSFP images in longitudinal two and four chamber views were acquired, and analyzed using feature tracking (FT) software. In addition to conventional LV and LA strain measurements, FT-derived LV and LA contours were further used to calculate chamber cross-sectional areas. HyF was approximated as the difference between the LV and LA maximal cross-sectional areas in the diastasis phase corresponding to the lowest LV-LA pressure gradient. Univariate and multivariate analyses while adjusting for appropriate variables were used to study the associations between HyF and age as well as diastolic function and strain indices.
RESULTS: HyF decreased significantly with age (R²=0.34, p < 0.0001). In addition, HyF was significantly associated with conventional indices of diastolic function and LA strain: E/A: R²=0.24, p < 0.0001; E\': R²=0.24, p < 0.0001; E/E\': R²=0.12, p = 0.0004; LA conduit longitudinal strain: R²=0.27, p < 0.0001. In multivariate analysis, associations with E/A (R2 = 0.39, p = 0.03) and LA conduit strain (R2 = 0.37, p = 0.02) remained significant after adjustment for age, sex, and body mass index.
CONCLUSIONS: HyF, estimated using FT contours, which are primarily used to quantify LV/LA strain on standard cardiac cine MRI, varied significantly with age in association with subclinical changes in ventricular filling. Its usefulness in cohorts of patients with left heart disease to detect LV-LA uncoupling remains to be evaluated.

Phenoxy radical coupling reactions are widely used in nature for the synthesis of complex molecules such as lignin. Their use in the laboratory has great potential for the production of high value compounds from the polyphenol family. While the enzymes responsible for the generation of the radicals are well known, the behavior of the latter is still enigmatic and difficult to control in a reaction flask. Previous work in our laboratory using the enzymatic secretome of B. cinerea containing laccases has shown that incubation of stilbenes leads to dimers, while incubation of phenylpropanoids leads to dimers as well as larger coupling products. Building on these previous studies, this paper investigates the role of different structural features in phenoxy radical couplings. We first demonstrate that the presence of an exocyclic conjugated double bond plays a role in the generation of efficient reactions. In addition, we show that the formation of phenylpropanoid trimers and tetramers can proceed via a decarboxylation reaction that regenerates this reactive moiety. Lastly, this study investigates the reactivity of other phenolic compounds: stilbene dimers, a dihydro-stilbene, a 4-O-methyl-stilbene and a simple phenol with the enzymatic secretome of B. cinerea. The observed efficient dimerization reactions consistently correlate with the presence of a para-phenol conjugated to an exocyclic double bond. The absence of this structural feature leads to variable results, with some compounds showing low conversion or no reaction at all. This research has allowed the development of a controlled method for the synthesis of specific dimers and tetramers of phenylpropanoid derivatives and novel stilbene derivatives, as well as an understanding of features that can promote efficient radical coupling reactions.

Introduction: Right-ventricular-to-pulmonary artery (RV-PA) coupling, measured as the ratio of tricuspid annular plane systolic excursion (TAPSE) to pulmonary artery systolic pressure (PASP), has emerged as a predictor factor in patients undergoing transcatheter aortic valvular replacement (TAVR). Right ventricular longitudinal shortening fraction (RV-LSF) outperformed TAPSE as a prognostic parameter in several diseases. We aimed to compare the prognostic ability of two RV-PA coupling parameters (TAPSE/PASP and the RV-LSF/PASP ratio) in identifying MACE occurrences. Method: A prospective and single-center study involving 197 patients who underwent TAVR was conducted. MACE (heart failure, myocardial infarction, stroke, and death within six months) constituted the primary outcome. ROC curve analysis determined cutoff values for RV-PA ratios. Multivariable Cox regression analysis explored the association between RV-PA ratios and MACE. Results: Forty-six patients (23%) experienced the primary outcome. No significant difference in ROC curve analysis was found (RV-LSF/PASP with AUC = 0.67, 95%CI = [0.58-0.77] vs. TAPSE/PASP with AUC = 0.62, 95%CI = [0.49-0.69]; p = 0.16). RV-LSF/PASP < 0.30%.mmHg-1 was independently associated with the primary outcome. The 6-month cumulative risk of MACE was 59% (95%CI = [38-74]) for patients with RV-LSF/PASP < 0.30%.mmHg-1 and 17% (95%CI = [12-23]) for those with RV-LSF/PASP ≥ 0.30%.mmHg-1; (p < 0.0001). Conclusions: In a contemporary cohort of patients undergoing TAVR, RV-PA uncoupling defined by an RV-LSF/PASP < 0.30%.mmHg-1 was associated with MACE at 6 months.

Metabolism, especially by CYP450 enzymes, is the main reason for mediating the toxification and detoxification of xenobiotics in humans, while some uncommon metabolic pathways, especially for emerging pollutants, probably causing idiosyncratic toxicity are easily overlooked. The pollution of sulfonamide antibiotics in aqueous system has attracted increasing public attention. Hydroxylation of the central amine group can trigger a series of metabolic processes of sulfonamide antibiotics in humans; however, this work parallelly reported the coupling and fragmenting initiated by amino H-abstraction of sulfamethoxazole (SMX) catalyzed by human CYP450 enzymes. Elucidation of the emerging metabolic profiles was mapped via a multistep synergy between computations and experiments, involving preliminary DFT computations and in vitro and in vivo assays, profiling adverse effects, and rationalizing the fundamental factors via targeted computations. Especially, the confirmed SMX dimer was shown to potentially act as a metabolism disruptor in humans, while spin aromatic delocalization resulting in the low electron donor ability of amino radicals was revealed as the fundamental factor to enable coupling of sulfonamide antibiotics by CYP450 through the nonconventional nonrebound pathway. This work may further strengthen the synergistic use of computations prior to experiments to avoid wasteful experimental screening efforts in environmental chemistry and toxicology.

The stress-generated potential (SGP) of bone is one of the mechanisms affecting bone remodeling including piezoelectricity and streaming potential. To explore the interactions between the piezoelectric and streaming potential, an experimental setup was designed that simultaneously applied a concentrated force and liquid pressure to wet bone. Using this device, the stress-generated potential of wet bone under the two types of loads was measured. The experimental results show that under a constant liquid pressure, the measured potential curves increase over time, and its increasing rate decrease as the concentrated force increase. The measured peak amplitudes of potential decrease as the liquid pressure increase under the same concentrated force whether loading or unloading. To explain the coupling mechanism of the found phenomena, an equivalent model with two voltage sources and three equivalent resistances was established, and the equivalent electrical relationship between the piezoelectric and streaming potential was obtained by analyzing the model. The analysis discussion implies that various factors have influence on the coupling relationship between streaming and piezoelectric potentials, and the factors can be summarized as the changes of the three equivalent resistances caused by piezoelectric and streaming potentials.

A thorough study on the amidation conditions of N-acetyl-l-phenylalanine using TBTU and various bases is reported for the synthesis of 2-(N-acetyl)-l-phenylalanylamido-2-deoxy-d-glucose (NAPA), a promising drug for the treatment of joints diseases. TBTU-mediated diastereoselective amidation reaction with 1,3,4,6-tetra-O-acetyl-β-d-glucosamine always gave racemization of N-acetyl-l-phenylalanine. The stereochemical retention under amidation conditions was studied in detail in the presence of difference bases and via other control experiments, evidencing the possibility to reduce racemization using pyridine as base.

Physiologic right ventricle-pulmonary artery (RV-PA) coupling may be impaired in patients with aortic stenosis (AS).
This study aimed to assess the incidence and prognostic significance of impaired RV-PA coupling in low-risk patients with symptomatic severe AS undergoing transcatheter aortic valve replacement or surgical aortic valve replacement.
RV-PA coupling was measured by transthoracic echocardiography as the ratio of tricuspid annular plane systolic excursion (TAPSE) to pulmonary artery systolic pressure (PASP) in patients in the PARTNER (Placement of Aortic Transcatheter Valve) 3 trial. The primary endpoint was the composite of all-cause mortality, stroke, and rehospitalization at the 2-year follow-up.
Among 570 low-risk patients included in the analysis, RV-PA uncoupling was defined by a TAPSE/PASP ratio ≤ 0.55 mm/mm Hg. At baseline, 222 of 570 (38.9%) patients had RV-PA uncoupling. At 2 years, patients with baseline RV-PA uncoupling had an increased incidence of the primary endpoint (19.1% vs 9.9%, P = 0.002), all-cause mortality (5.9% vs 0.6%, P < 0.001), cardiovascular mortality (4.1% vs 0.6%, P = 0.003), and rehospitalization (13.5% vs 7.3%, P = 0.018). On multivariable analysis, baseline RV-PA uncoupling remained an independent predictor of the primary endpoint at 2 years (HR: 1.92; 95% CI: 1.04-3.57; P = 0.038).
In patients with symptomatic severe AS at low surgical risk undergoing transcatheter aortic valve replacement or surgical aortic valve replacement, baseline RV-PA uncoupling defined by TAPSE/PASP ≤ 0.55 mm Hg was associated with adverse clinical outcomes at 2 years, including all-cause mortality, cardiovascular mortality, and rehospitalization.

BACKGROUND: Recent studies have described a novel left atrioventricular coupling index (LACI), which had a better prognostic value in predicting cardiovascular events than individual left atrial (LA) or left ventricular (LV) variables.
OBJECTIVE: To identify determinants of LACI and its 10-year annual change (ΔLACI), measured by cardiac magnetic resonance (CMR), and to better understand the variables governing this left atrioventricular coupling.
METHODS: In the Multi-Ethnic Study of Atherosclerosis, 2112 study participants, free from cardiovascular disease at baseline, had LACI assessed by CMR imaging at baseline (LACIBaseline; 2000-2002) and 10 years later (2010-2012). The LACI was defined as the ratio of LA to LV end-diastolic volumes. Linear regression analyses were performed to identify independent determinants of LACIBaseline and ΔLACI.
RESULTS: In the 2112 participants (mean age 58.8±9.1 years; 46.6% male), after adjustment for all covariates, age was independently associated with LACIBaseline (R2=0.10, slope=0.16) and ΔLACI (R2=0.15, slope=0.008; both P<0.001). African Americans had the highest LACIBaseline value (18.0±7.7%). Although there was no difference in LACIBaseline between women and men (P=0.19), ΔLACI was higher in women (1.0±1.1 vs 0.8±1.1%/year; P<0.001). Diabetes and higher body mass index (BMI) were independently associated with LACIBaseline (both P<0.001). LACIBaseline was independently associated with LV myocardial fibrosis markers (native T1: R2=0.11, slope=0.09 [P=0.038]; extracellular volume: R2=0.08, slope=0.28 [P=0.035]) and N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) concentration (R2=0.10, slope=-1.11; P<0.001), but was not associated with interleukin 6 or high-sensitivity C-reactive protein.
CONCLUSIONS: Age, sex, ethnicity, diabetes and BMI were independent determinants of LACI. LACI was independently associated with myocardial fibrosis markers and NT-proBNP concentration.

Coordination between economic development (ED) and ecological environment (EE) is an important challenge for high-quality urban development. Taking the panel data related to the ED and EE of the Yangtze River Delta urban agglomeration (YUA) from 2009 to 2019 as the research objective, the evaluation system of ED and EE was constructed by introducing the coupling coordination degree model and the gray correlation degree model to analyze their development indices, coupling coordination degree and gray correlation degree in two spatial and temporal dimensions. Research results: (1) The ED indexes and EE indexes of the 26 cities in the YUA have obvious differences in different cities, and there is no synergy between the two indices. (2) The coupling coordination degree of the YUA shows a pattern of high in the east and low in the west, high in the center and low in the north and south in space, and an overall increasing trend in time. (3) In terms of gray correlation, the correlation between ED quality dimension and EE level dimension is the highest. According to the conclusion, when both the economy and environment present consistency at a high level, it will help the city\'s economy to develop more efficiently and rapidly.

The effect of the coupling texture on the friction and wear of a piston rod-rubber seal pair under lubricating conditions is studied in this paper. Crescentiform textures with different area densities were fabricated on high carbon chromium bearing steel (GCr15) and ethylene propylene diene monomer (EPDM) materials by using a laser marking machine. We compare and analyze the effects of untextured, single-textured, and coupling-textured surfaces on the friction characteristics of the piston rod-rubber seal pair by conducting tests on the reciprocating module of the UMT-2 friction and wear testing machine. The results showed that the coupling-textured surface had the lowest coefficient of friction and wear compared to the untextured and single-textured surfaces. When the normal load was 10 N under the optimal coupling texture area density (6.4%), the friction and wear of the sealing pair decreased the most. Compared with the untextured surface, the friction coefficient was reduced by 27.9% and the wear amount was reduced by 30.0%; compared with the single-textured surface, the friction coefficient was reduced by 18.9%, and the wear amount was reduced by 23.8%. The coupling effect generated by the coupling texture effectively enhanced the formation and stabilization of the oil lubricant film and effectively captured wear debris, preventing it from continuously scratching the surface and reducing wear and roughness.