Development of a three-dimensional finite element model of a human tibia using experimental modal analysis.

The modal analysis of a human tibia consisted of characterizing its dynamic behavior by determining natural frequency, damping ratio and mode shapes. Two methods were used to perform the modal analysis: (1) a finite element method (structural model); (2) an experimental modal analysis (modal model). The experimental modal model was used to optimize the structural model. After optimization, differences in results between the two models were found to be due only to mechanical properties and mass distribution. The influences of boundary conditions and geometric properties (such as inertia and length) were eliminated by the finite element model itself. The percent relative error between the two methods was approximately 3%, corresponding to the standard deviation of the measured frequencies. For the frequency range considered, the mode shapes were bending modes in two different vibration planes (latero-medial and sagittal), with a slight torsion effect due to the twisted geometry of the tibia.

(Schiff base) divalent group 14 element species: manganese and iron complexes (Salen)M=Mn(Co)2(eta 5-C5H5) (M14 = Ge, Sn, Pb) and (Salen)Sn=Fe(CO)4.

Syntheses of the (divalent group 14 species)dicarbonyl(cyclopentadienyl)manganese (Salen)M=Mn(CO)2(eta 5-C5H5) [M = Ge (1), Sn (2), Pb (3)] and [(Salen)tin(II)]tetracarbonyliron (Salen)Sn=Fe(CO)4 (4) are reported. The structures of 2 and 4 were determined by X-ray crystallography. The observed Sn-Mn bond length, 2.4428(7) A, is the shortest distance observed for this type of bond and corresponds to considerable multiple bonding between these atoms. In complex 4, the iron atom has a slightly distorted trigonal-bipyramidal coordination sphere; the (Salen)tin(II) ligand occupies an axial site, indicating that it functions in this complex as a strong sigma-donor and weak pi-acceptor ligand. Crystal data for 2: orthorhombic, P2(1)2(1)2(1), a = 6.972(1) A, b = 15.678(2) A, c = 19.032(2) A, alpha = beta = gamma = 90 degrees, V = 2080.3(5) A3, T = 173(2) K, Z = 4. Crystal data for 4: triclinic, P1, a = 8.465(2) A, b = 9.795(3) A, c = 13.213(4) A, alpha = 105.55(3) degrees, beta = 105.15(3) degrees, gamma = 100.84(3) degrees, V = 978.7(5) A3, T = 173(2) K, Z = 2.

[Initial response to treatment with erythropoietin in anemia caused by chronic renal insufficiency]. / Respuesta inicial al tratamiento con eritropoyetina en la anemia de la insuficiencia renal crónica.

The achievement of recombinant human erythropoietin (r-HuEpo) supposed an important advance in the treatment of the anaemia of chronic renal failure. The results achieved with r-HuEpo in seven patients with chronic renal failure subjected to haemodialysis who required repeated blood transfusions are reported. The duration of treatment was 12 weeks at an initial doses of 50 U/Kg. A significant increase of haematocrit, red-cell count, haemoglobin, reticulocytes and platelets was attained. The decrease of serum iron, transferrin saturation index and ferritin in spite of oral iron therapy was striking. None of the patients required blood transfusion during the period of study, and all but one referred subjective improvement. No severe adverse effects were observed, except for one case of thrombosis of arteriovenous fistula, whose relation with this treatment is dubious. Although this is a short-term preliminary study, it can be inferred that r-HuEpo treatment is effective and free of major risks for the anaemia of chronic renal failure.