ABSTRACT
At the onset, multiple sclerosis (MS) in children is characterized by a phase of active inflammation with extensive demyelination of the white matter of the CNS, which often mimics this nosology with a whole spectrum of inflammatory demyelinating diseases such as ADEM, anti-MOG encephalitis, ONMSD. In order to formalize the diagnostic process, the International Pediatric Multiple Sclerosis Study Group (IPMSSG) proposed diagnostic criteria for the main immune-mediated demyelinating diseases of the CNS in children, which, in theory, should simplify the diagnostic search. However, in practice, the range of nosologies in the course of differential diagnosis is much wider and often it is not possible to establish an unambiguous diagnosis in the early stages. The authors analyze their own clinical observations based on a sample of 100 pediatric patients with a referral diagnosis of «MS?¼ and describe a clinical case of the onset of highly active MS with an assessment of the dynamics of the clinical and paraclinical course of the disease.
Subject(s)
Encephalomyelitis, Acute Disseminated , Multiple Sclerosis , Child , Diagnosis, Differential , Encephalomyelitis, Acute Disseminated/diagnosis , Humans , Magnetic Resonance Imaging , Multiple Sclerosis/diagnosisABSTRACT
The stability of ferroelectric domain patterns at the nanoscale has been a topic of much interest for many years. We investigated the relaxation of the polarized state created by application of a local electric field using a conductive tip of a scanning probe microscope for the model uniaxial relaxor system SrxBa1-xNb2O6 (SBN) in its pure and Ce-doped form. The temporal relaxation of the induced PFM contrast was measured at various temperatures. The average value of the induced contrast decreases during heating for all investigated crystals. Below the freezing temperature the induced state remains stable after an initial relaxation. Above the freezing temperature the induced state is unstable and gradually decays with time. The stability of the induced state is strongly affected by the measuring conditions, so continuous scanning results in a faster decay of the poled domain. The obtained effects are attributed to a decrease of the induced polarization and backswitching of the polarized area under the action of the depolarization field.
