Synthesis and crystallographic, spectroscopic and computational characterization of 3,3',4,4'-substituted biphenyls: effects of OR substituents on the intra-ring torsion angle.

Presented here are the synthesis, characterization and study (using single crystal X-ray diffraction, Raman scattering, quantum mechanics calculations) of the structures of a series of biphenyls substituted in positions 3, 3', 4 and 4' with a variety of R (R = methyl, acetyl, hexyl) groups connected to the biphenyl core through oxygen atoms. The molecular conformation, particularly the torsion angle between aromatic rings has been extensively studied both in the solid as well as in the liquid state. The results show that the compounds appearing as rigorously planar in the solid present instead a twisted conformation in the melt. The solid versus melt issue strongly suggests that the reasons for planarity are to be found in the packing restraints. A `rule of thumb' is suggested for the design of biphenyls with different molecular conformations, based on the selection of the OR substituent.

Femoral offset and its relationship to femoral neck-shaft angle and torsion angle / Desplazamiento femoral y su relación con el ángulo cuello-diáfisis femoral y el ángulo de torsión

The aims to study the femoral offset and its relationship to femoral neck-shaft angle and torsion angle. One hundred paired (50 males and 50 females) Chinese femurs were used to measure the femoral offset, femoral neck-shaft angle and torsion angle. The data were analyzed by SPSS software. Femoral offsets were male right 44.40±4.56 mm, left 42.70±4.95 mm; female right 39.90±6.00 mm, left 38.90±6.18 mm. Femoral torsion angles were male right 6.02±10.85°, left 7.08±9.30°; female right 10.02±11.69, ° left 6.02±10.85°. Neck-shaft angles were male right 131.80±4.36°, left 134.00±4.78°; female right 132.10±5.94°, left 132.80±4.93°. There were no sexual differences in the two femoral angles (P>0.05) while there was a significant sexual difference in the femoral offset (P<0.01). The differences between left and right femoral offset and neck-shaft angle were significant (P<0.01). Clinically, our results indicate that FO could be obtained using the regression equation when the torsion angle and/or neck-shaft angle is measured.

El objetivo fue estudiar el desplazamiento femoral y su relación con el ángulo cuello-diáfisis femoral y el ángulo de torsión. Se utilizaron 100 pares de fémures (50 hombres y 50 mujeres) y se tomaron las medidas del desplazamiento femoral, ángulo cuello-diáfisis femoral y ángulo de torsión. Los datos fueron analizados con el software SPSS. El desplazamiento femoral en los hombres fue 44,40±4,56 mm en el lado derecho y 42,70±4,95 mm en el lado izquierdo, y en las mujeres, fue de 39,90±6,00 mm y 38,90±6,18 mm para el lado derecho e izquierdo, respectivamente. El ángulo de torsión femoral del lado derecho en los hombres fue 6,02±10,85° y 7,08±9,30° del izquierdo; mientras que en las mujeres, fue de 10,02±11,69° y 6,02±10,85° para el lado derecho e izquierdo, respectivamente. Los ángulos cuello-diáfisis fueron 131,80±4,36° en el lado derecho, y 134,00±4,78° en el izquierdo, para los hombres, mientras que en las mujeres fueron de 132,10±5,94° en el lado derecho y 132,80±4,93° en el izquierdo. No hubo diferencias según sexo en los dos ángulos femorales (P>0,05), mientras que si hubo una diferencia significativa en el desplazamiento femoral (P<0,01). Las diferencias entre el desplazamiento femoral izquierdo y derecho, y el ángulo cuello-diáfisis fueron significativas (P<0,01). Clínicamente, nuestros resultados indican que el desplazamiento femoral podría obtenerse utilizando la ecuación de regresión cuando se mide el ángulo de torsión o el ángulo cuello-diáfisis.

Intraobserver and interobserver reliability of radial torsion angle measurements by a new and alternative method with computed tomography

OBJECTIVE: To evaluate the intraobserver and interobserver reliability of radial torsion angle measurement using computed tomography. METHODS: Twelve pairs of cadaver radii and 116 forearms from 58 healthy volunteers were evaluated using axial computed tomography sections measured at the level of the bicipital tuberosity and the subchondral region of the radius. During digital imaging, the angle was formed by two lines, one diametrically perpendicular to the radial tubercle and the other tangential to the volar rim of the distal joint surface. Measurements were performed twice each by three observers. RESULTS: In cadaveric bones, the mean radial torsion angle was 1.48º (-6º - 9º) on the right and 1.62º (-6 º - 8º) on the left, with a mean difference between the right and left sides of 1.61º (0º - 8º). In volunteers, the mean radial torsion angle was 3.00° (-17° - 17°) on the right and 2.91° (-16°- 15°) on the left, with a mean difference between the sides of 1.58º (0º - 7º). There was no significant difference between each side. The interobserver correlation coefficient for the cadaver radii measurements was 0.88 (0.72 - 0.96) and 0.81 (0.58 - 0.93) for the right and left radius, respectively, while for the volunteers, the difference was 0.84 (0.77 - 0.90) and 0.83 (0.75 - 0.89), respectively. Intraobserver reliability was high. CONCLUSION: The described method is reproducible and applicable even when the radial tubercle has a rounded contour.