Thermal and photochemical control of nitro-nitrito linkage isomerism in single-crystals of [Ni(medpt)(NO₂)(η²-ONO)]

The known complex [Ni(medpt)(η1-NO2)(η2-ONO)] 1 (medpt = 3,3′-diamino-N-methyldipropylamine) crystallises in the monoclinic space group P21/m with 1.5 molecules in the asymmetric unit with two different η1-NO2 ligand environments in the crystal structure. At 298 K the molecule (A) sitting in a general crystallographic site displays a mixture of isomers, 78% of the η1-NO2 isomer and 22% of an endo-nitrito–(η1-ONO) form. The molecule (B) sitting on a crystallographic mirror plane adopts the η1-NO2 isomeric form exclusively. However, a variable temperature crystallographic study showed that the two isomers were in equilibrium and upon cooling to 150 K the η1-ONO isomer converted completely to the η1-NO2 isomer, so that both independent molecules in the asymmetric unit were 100% in the η1-NO2 form. A kinetic analysis of the equilibrium afforded values of ΔH = −9.6 (±0.4) kJ mol−1, ΔS = −21.5 (±1.8) J K−1 mol−1 and EA = −1.6 (±0.05) kJ mol−1. Photoirradiation of single crystals of 1 with 400 nm light, at 100 K, resulted in partial isomerisation of the η1-NO2 isomer to the metastable η1-ONO isomer, with 89% for molecule (A), and 32% for molecule (B). The crystallographic space group also reduced in symmetry to P21 with Z′ = 3. The metastable state existed up to a temperature of 150 K above which temperature it reverted to the ground state. An analysis of the crystal packing in the ground and metastable states suggests that hydrogen bonding is responsible for the difference in the conversion between molecules (A) and (B)

A biologic without guidelines: the YODA project and the future of bone morphogenetic protein-2 research

Scientific Assessment and Innovation in Neurosurgical Treatment Strategie

Modelo de avaliação físico-funcional da coluna vertebral Modelo de evaluación físico-funcional de la columna vertebral Spinal cord physical assessment model

O presente trabalho descreve os métodos semiológicos que devem ser empregados na exploração postural e na avaliação da coluna vertebral, dentro da assistência à saúde em nível primário. Os métodos empregados nessa propedêutica sistematizada englobam o histórico e um exame físico específico composto de: inspeção estática e exame postural; inspeção dinâmica; palpação; avaliação da força e flexibilidade musculares; exame neurológico e manobras especiais.<br>El presente trabajo describe un modelo de evaluación fisico-funcional que puede ser empleado en la evaluación postural y en la valoración de la columna vertebral dentro de la atención a la salud en nivel primario. Los métodos empleados en esa propedéutica sistematizada engloban la historia clínica y un examen físico específico compuesto de inspección estática y examen de la postura, inspección dinámica, palpación, evaluación de la fuerza y flexibilidad muscular, examen neurológico y maniobras especiales.<br>The study describes semiological methods that must be employed in posture and spinal cord evaluation, considering primary health care. The methods used in this study involve the patient´s history, and a specific physical examination which includes a static inspection, posture examination, dynamic inspection, palpation, muscle strength and flexibility assessment, neurological examination and special tests