Correlation between fat infiltration of paraspinal muscle and L4 degenerative lumbar spondylolisthesis in asymptomatic adults.

OBJECTIVE: To explore the relationship between different indicators of the degree of fat infiltration and L4 Degenerative lumbar spondylolisthesis (DLS). METHODS: 128 patients received annual health check-up underwent lumbar lateral Digital Radiography (DR) and abdominal Computed tomography (CT) imaging were enrolled. The DLS group included 60 patients diagnosed with DLS, and the control group included 68 patients without DLS. The data collected included vertebral density of L4-L5, fat infiltration ratio (FIR) of paravertebral muscle (PM) and psoas major muscle (PMM), skeletal muscle density of PM and PMM, low attenuation muscle ratio (LTR) of PM and PMM, paraspinal muscle density (PMD), psoas major muscle density (PMMD), low attenuation muscle density (LMD) of PM and PMM, facet joint angle (FJA), facet joint degeneration (FJD), etc. RESULTS: PM FIR and PM LTR were weakly positively correlated with the degree of L4 DLS, and there was a weak negative correlation between PMD and the degree of L4 DLS in asymptomatic adults (P < 0.05). Logistic regression analysis showed that PM FIR was an independent related factor of L4 DLS (Q3 vs. Q1, OR = 3.746, 95% CI: 1.076-13.048, p = 0.038). ROC curve analysis showed that the PM FIR has a high predictive value for L4 DLS in asymptomatic adults. CONCLUSION: The indicator of PM FIR was an independent related factor of L4 DLS in asymptomatic adults. It has a high predictive value for L4 DLS and can be applied as a potential target for clinical treatment of L4 DLS in asymptomatic adults.

Characteristic analysis of broadband plasmonic emitting devices based on transformation optics.

The crescent nanostructure with gain medium inside is theoretically studied to analyze the characteristic of plasmonic emitting with wide bandwidth. An accurate analytical model is built based on the transformation optics. In this model, the poles of the electrostatic potential function are in the second and the fourth quadrant of the complex plane if the imaginary part of the relative permittivity of the gain medium is larger than the loss compensation threshold, and then the extinction cross section is to be negative by integrating the electrostatic potential over the half complex plane via an inverse Fourier transform. The positive extinction cross section corresponds to absorption, and the negative corresponds to emission. The proposed analytical model agrees well with the numerical simulation results based on the finite element method, to give a physical insight into the loss compensation property of the plasmonic nanostuctures. Results show that the negative extinction cross section is realizable by introducing the gain medium into a plasmonic crescent nanowire, which is equivalent to an emitting device with wide bandwidth.

Photochemically grown silver nanodecahedra with precise tuning of plasmonic resonance.

The ability to control the local surface plasmonic resonance (LSPR) absorption peaks of silver nanoparticles will greatly broaden the scope of their practical application. Conventional methods tune the LSPR peaks by modifying the shape or size of the silver nanoparticles. Here, we present a novel method to tune the LSPR band by controlling the particle corner sharpness. A modified photochemical method was used to prepare silver nanoparticles. It was found that the nanoparticles irradiated using light-emitting diodes (LEDs) with a wavelength of 455 nm were decahedral, although the reaction temperature was different. However, the in-plane dipole LSPR peak of the as-prepared silver nanodecahedra exhibited an evident red shift from 460 nm to 500 nm during the synthesis process, and the wavelength of the LSPR peak increased linearly as the reaction time increased. A numerical simulation conducted to investigate the mechanism behind the shift revealed that the red shift of the LSPR peak was mainly induced by the evolution of the corner sharpness of the silver nanodecahedra. These results demonstrated the effectiveness of the method in precisely tuning the LSPR peak by controlling the reaction time. By turning off the irradiation light, the photochemical process could be immediately terminated, and the LSPR peak of the silver nanoparticles remained constant. Compared with conventional methods, the present tuning precision can reach 1 nm.

Benzyl 3-[(E)-benzyl-idene]dithio-carbazate.

Crystals of the title compound, C(15)H(14)N(2)S(2), were obtained from a condensation reaction of benzyl dithio-carbazate and benzaldehyde. The mol-ecule assumes an E configuration about the N=C double bond. The phenyl ring of the thio-ester group is nearly perpendicular to the dithio-carbazate plane, with a dihedral angle of 84.60 (5)°. In the crystal structure, inter-molecular N-H⋯S hydrogen bonding links adjacent mol-ecules to form a centrosymmetric supra-molecular dimer.

Methyl 3-[(E)-1-(4-amino-phen-yl)ethyl-idene]dithio-carbazate.

The title compound, C(10)H(13)N(3)S(2), was obtained from a condensation reaction of methyl dithio-carbazate and 4-amino-acetophenone. In the crystal structure, the nearly planar mol-ecule assumes an E configuration, the benzene ring and dithio-carbazate group being located on opposite sides of the N=C bond. C-H⋯π inter-actions and N-H⋯S hydrogen bonding are present in the crystal structure.

Benzyl 3-[(E)-furfuryl-idene]dithio-carbazate.

In the title compound, C(13)H(12)N(2)OS(2), the mol-ecule assumes an E configuration, with the furan ring and dithio-carbazate units located on opposite sides of the N=C double bond. In the crystal structure, mol-ecules are linked via two inter-molecular N-H⋯S hydrogen bonds to form centrosymmetric dimers.

(E)-2-Furyl methyl ketone 2,4-dinitro-phenyl-hydrazone.

Crystals of the title compound, C(12)H(10)N(4)O(5), were obtained from a condensation reaction of 2,4-dinitro-phenyl-hydrazine and 2-furyl methyl ketone. The mol-ecule displays a nearly planar structure, and the furan ring is slightly twisted by a dihedral angle of 12.62 (6)° with respect to the phenyl-hydrazone plane. The face-to-face separation of 3.287 (7) Šbetween parallel benzene rings of adjacent mol-ecules indicates the existence of π-π stacking between dinitro-phenyl rings in the crystal structure.

(E)-Methyl 1,3-thia-zol-2-yl ketone 2,4-dinitro-phenyl-hydrazone.

Crystals of the title compound, C(11)H(9)N(5)O(4)S, were obtained from a condensation reaction of 2,4-dinitro-phenyl-hydrazine and methyl 1,3-thia-zol-2-yl ketone. Excluding two methyl H atoms, the mol-ecule displays a planar structure, the dihedral angle between the terminal thia-zole and benzene rings being 1.82 (8)°. The imino group links with adjacent nitro and thia-zole groups by intra-molecular bifurcated hydrogen bonding. The centroid-centroid separation of 3.7273 (11) Šbetween nearly parallel benzene and thia-zole rings of adjacent mol-ecules indicates the existence of π-π stacking in the crystal structure. Weak inter-molecular C-H⋯O hydrogen bonding is also observed.

Methyl 3-[(E)-furfuryl-idene]dithio-carbazate.

The mol-ecule of the title Schiff base compound, C(7)H(8)N(2)OS(2), prepared by the reaction of methyl dithio-carbazate and furfural in an ethanol solution under reflux, adopts an E configuration; the dithio-carbazate and furan units are located on opposite sides of the C=N double bond. The planar dithio-carbazate group is twisted slightly with respect to the furan ring, making a dihedral angle of 5.2 (1)°. Adjacent mol-ecules are linked by N-H⋯S hydrogen bonding to form a supra-molecular dimer across an inversion center.

(E)-2-Acetyl-pyrazine 4-nitro-phenyl-hydrazone.

In the title compound, C(12)H(11)N(5)O(2), the mol-ecule adopts an E configuration, with the benzene and pyrazine rings located on opposite sides of the N=C double bond. The face-to-face separations of 3.413 (14) and 3.430 (8) Å, respectively between parallel benzene rings and between pyrazine rings indicate the existence of π-π stacking between adjacent mol-ecules. The crystal structure also contains N-H⋯N and C-H⋯O hydrogen bonding.

(E)-N'-[1-(4-Amino-phen-yl)ethyl-idene]benzohydrazide.

Crystals of the title compound, C(15)H(15)N(3)O, were obtained from a condensation reaction of benzohydrazide and 1-(4-amino-phen-yl)ethanone. The mol-ecule assumes an E configuration with the amino-phenyl and benzohydrazide units located on opposite sites of the C=N double bond. In the crystal structure, the benzene rings of the mol-ecule are slightly twisted with respect to the central hydrazide, the dihedral angles being 18.22 (12) and 27.62 (12)°. The crystal structure contains inter-molecular N-H⋯O and weak C-H⋯N hydrogen bonding.

(E)-Methyl 3-(2-nitro-benzyl-idene)dithio-carbazate.

The asymmetric unit of the title compound, C(9)H(9)N(3)O(2)S(2), contains two independent mol-ecules, A and B, with similar bond dimensions. In both mol-ecules, the nitro group is tilted with respect to the aromatic ring [dihedral angles 32.0 (1)° in mol-ecule A and 34.0 (1)° in mol-ecule B]. The dithio-carbazate unit is nearly coplanar with the aromatic ring in both mol-ecules. For mol-ecule B, pairs of mol-ecules are linked by N-H⋯O and C-H⋯O hydrogen bonds about a centre of symmetry to form a dimer, whereas mol-ecules A are not involved in hydrogen bonding in the crystal structure.