Spontaneous intracerebral haemorrhage secondary to 5-ALA-induced thrombocytopaenia in a paediatric patient: case report and literature review.

INTRODUCTION: The primary objective of neurosurgical management of malignant gliomas is maximal safe resection of the tumour. One of the main obstacles in achieving this is the ability to accurately discriminate between tumour edges and the surrounding healthy brain tissue. The use of fluorescence-guided surgery utilising 5-aminolevulinic acid (5-ALA), first introduced more than 20 years ago, has become an invaluable adjunct in high-grade glioma surgery in adults. However, as 5-ALA is not licensed for use in paediatric patients, the safety profile for such use remains undetermined. CASE REPORT: We describe the case of a 4-year-old boy who underwent 5-ALA-guided resection of a fourth ventricle anaplastic ependymoma. Although complete resection was achieved and the patient awoke from surgery well with no neurological deficits, the patient developed acute transaminitis, anaemia, thrombocytopaenia and coagulopathy postoperatively. The patient had a sudden neurological deterioration on postoperative day 2; imaging revealed that he had suffered a spontaneous right frontal intracerebral haemorrhage. The patient returned to theatre for surgical decompression and evacuation of the haematoma, and ultimately went on to make a full recovery. CONCLUSION: The use of 5-ALA in paediatric patients can be helpful in maximising surgical resection, but the associated safety profile remains undefined. Further research is urgently warranted in order to characterise the efficacy and risk of the use of 5-ALA in the paediatric population.

Metal nanoparticle ensembles: tunable laser pulses distinguish monomer from dimer vibrations.

Resonant interaction of laser pulses with plasmons is used to identify vibrations associated with isolated spheres and pairs of contacting spheres in a system of gold nanoparticles. The optical pulses generate coherent mechanical oscillations of both monomers and dimers in the 5-150 GHz range, the amplitudes of which exhibit a strong enhancement when the laser central wavelength is tuned to resonate with the corresponding plasmon. Because of the resonant selection in the excitation process, the widths of the acoustic modes are significantly smaller than broadening caused by the spread in radii in the ensemble.

Primary intradural/extradural Ewing's sarcoma of the sacral spine: A case report and literature review.

BACKGROUND: Ewing's sarcoma (ES) is a malignant mesenchymal tumor, most often found in the long bones, and usually affecting children and adolescents in the second decade of life. ES of the spine is a clinical rarity. CASE DESCRIPTION: A 45-year-old male presented with a 3-month history of lower back pain which acutely worsened in conjunction with urinary retention. The magnetic resonance imaging revealed a mass extending from L5 to S2 with additional extension through the left S2-3 neural foramen. The metastatic workup was negative. At surgery, the lesion was both intradural and extradural. Following complete surgical resection, the patient was later treated with radiation and chemotherapy. CONCLUSION: Here, we report an adult male who acutely presented with low back pain attributable to primary intradural/extradural sacral ES.

Damping by bulk and shear viscosity of confined acoustic phonons for nanostructures in aqueous solution.

A nanoparticle in aqueous solution is modeled as a homogeneous elastic isotropic continuum sphere in contact with an infinite viscous compressible Newtonian fluid. The frequencies and damping of the confined vibrational modes of the sphere are calculated for the material parameters of a CdSe nanoparticle in water and a poly(methyl methacrylate) nanosphere in water. Although the effects of viscosity are found to be negligible for macroscopic objects, for nanoscale objects, both the frequency and damping of the vibrational modes are significantly affected by the viscosity of the liquid. Furthermore, both shear viscosity and bulk viscosity play an important role. A model of the spherical satellite tobacco mosaic virus consisting of outer solid layers with a water core is also investigated, and the viscosity of the water core is found to significantly damp the free vibrational modes. The same approach can be applied for nonspherical geometries and also to viscoelastic nanoparticles.

Comment on "Estimate of the vibrational frequencies of spherical virus particles".

This Comment corrects some errors which appeared in the calculation of an elastic sphere eigenenergies. As a result, the symmetry of the mode having the lowest frequency is changed. Also a direction for calculating the damping of these modes for embedded elastic spheres is given.

Surface plasmons and vibrations of self-assembled silver nanocolumns.

Optical and vibrational properties of novel self-assembled silver nanocolumns are studied experimentally and theoretically. The split of the surface plasmon resonance into transverse and longitudinal modes verifies the one-dimensional character of the nanocolumns. In this work, we have identified the acoustic vibration modes of the nanocolumns using Raman scattering, as spheroid-like modes (l = 2, m = +/-2) involving vibrations of the nanocolumns along their minor axes and the existence of surface plasmon-vibration coupling mechanisms.

Long lived acoustic vibrational modes of an embedded nanoparticle.

Classical continuum elastic calculations show that the acoustic vibrational modes of an embedded nanoparticle can be lightly damped even when the longitudinal plane wave acoustic impedances Z(o)=rhov(L) of the nanoparticle and the matrix are the same. It is not necessary for the matrix to be less dense or softer than the nanoparticle in order to have long lived vibrational modes. A corrected formula for acoustic impedance is provided for the case of longitudinal spherical waves. Continuum boundary conditions do not always accurately reflect the microscopic nature of the interface between the nanoparticle and the matrix, and a multilayer model of the interface reveals the possibility of additional reduction of mode damping.