Search

Systolic blood pressure (SBP) is significantly associated with body composition in children and adolescents. However, which one of the components of body composition is the dominant contributor to SBP in children and adolescents remains unclear. We, therefore, aimed to determine the dominant contributor to SBP among components of body composition in a large cohort of American children and adolescents derived from the National Health and Nutrition Examination Survey with cross-sectional analysis. In total, 13 618 children and adolescents (median age 13 years; 6107 girls) with available data on whole-body dual-emission X-ray absorptiometry measurements were included. Multiple linear regression showed that SBP was associated with higher total fat-free mass in boys (β = 0·49, P < 0·001) and girls (β = 0·47, P < 0·001) and with higher total fat mass only in boys (β = 0·12, P < 0·001) after adjustment for covariates. When taking fat distribution into consideration, SBP was associated with higher trunk fat mass (boys: β = 0·28, P < 0·001; girls: β = 0·15, P < 0·001) but negatively associated with leg fat mass (Boys: β = −0·14, P < 0·001; Girls: β = −0·11, P < 0·001), in both boys and girls. Dominance analysis showed that total fat-free mass was the dominant contributor to SBP (boys: 49 %; girls: 55·3 %), followed by trunk fat mass (boys: 32·1 %; girls: 26·9 %); leg fat mass contributed the least to SBP in boys (18·9 %) and girls (17·8 %). Our findings indicated that total fat-free mass was not only associated with SBP but also the most dominant contributor to SBP variation in American children and adolescents. [ABSTRACT FROM AUTHOR]

[Objectives] Propeller noise and hydrodynamic noise are the key and difficult points of submarine noise control. Therefore,it is necessary to carry out propeller excitation force and hydrodynamic noise prediction research.[Methods] With the SUBOFF submarine and DTMB 4383 propeller as the calculation object,combined with the large eddy simulation turbulence model and the infinite element method,the change rule of the propeller excitation force in the non-uniform accompanying flow field of the submarine and the influence of the propeller on the surface pressure field of the submarine are analyzed. The ACTRAN acoustic calculation software is used to numerically predict the hydrodynamic noise performance of the integrated boat.[Results] The calculation results show that the components of the propeller excitation force have the same pulsation frequency,the pulsation peak is mainly the first-order leaf frequency,and the horizontal force pulsation and vertical force pulsation are greater than the thrust pulsation. The high pressure area exists at the bow,command station,tail and blade tip of submarine, which is the main contribution point of hydrodynamic noise. The hydrodynamic noise of the boat and propeller is mainly concentrated in the low frequency band,and the butterfly distribution is more obvious as the frequency increases. Compared with the propeller's full-body submarine,the sound pressure value of the submarine's characteristic point increases sharply due to the rotation of the propeller,and the variation of the radiated sound field is also large.[Conclusions] The research results can provide reference for the propeller design of the propeller.

A series of Ti-doped W18O49 samples were prepared using a convenient solvothermal route. Due to the synergistic effect of doped Ti and oxygen vacancies, the samples showed excellent visible-light photochromic properties. Their performances as light-printable rewritable paper and smart windows showed great application value and promotion value. [ABSTRACT FROM AUTHOR]

Based on the bis-β-diketonate-Dy2 metalloligand [Dy2(pbth)4]·2Et3N (1, pbth = (3z,3′z)-4,4′-(1,3-phenylene)bis(1,1,1-trifluoro-4-hydroxybut-3-en-2-one)), six dinuclear complexes with eight-coordinated geometries were synthesized solvothermally through different capping N-donor coligands or solvent systems. These complexes are namely [Dy2(pbth)3(Phen)2]·2C2H5OH (2), [Dy2(pbth)3(BPhen)2]·2C2H5OH (3), [Dy2(pbth)3(Dppz)2]·2C2H5OH (4), [Dy2(pbth)3(Dppz)2]·2CH3OH (4a), [Dy2(pbth)3(4-Dmbp)2]·CH3OH·C2H5OH (5) and [Dy2(pbth)3(5-Dmbp)2]·CH3OH (6) (Phen = 1,10-phenanthroline, BPhen = 4,7-diphenyl-1,10-phenanthroline, dppz = dipyrido [3,2-a:2′,3′-c] phenazine, 4-Dmbp = 4,4′-dimethyl-2,2′-bipyridyl, 5-Dmbp = 5,5′-dimethyl-2,2′-bipyridyl), respectively. In the synthetic processes of 2–6, one of four bis-β-diketonate ligands in the metalloligand is replaced by two capping N-donor coligands. The coordination geometries, metal distances and M–L–M torsion angles of the synthesized complexes are perceptibly fine-tuned by the modification of the capping N-donor coligands or the latticed solvent molecules. Systematic magnetic investigations indicate the different magnetic relaxation dynamics of 1–6. Complex 1 displays no characteristics of single-molecule magnets (SMMs), while complexes 2–6 exhibit SMM behaviours in the absence of a static magnetic field. Complexes 2 and 3 possess effective energy barriers (Ueff) of 110.18 (2) K and 133.21 (4) K, respectively. Theoretical analysis based on ab initio calculation provides some interpretations of experimental observation. [ABSTRACT FROM AUTHOR]