Amorphous S-flurbiprofen was obtained by the melt quench/cooling method. Dielectric measurements performed in the isochronal mode, conventional and temperature modulated differential scanning calorimetry (TMDSC) studies showed a glass transition, recrystallization, and melting. The different parameters characterizing the complex molecular dynamics of amorphous S-flurbiprofen that can have influence on crystallization and stability were comprehensively characterized by dielectric relaxation spectroscopy experiments (isothermal mode) covering a wide temperature (183 to 408 K) and frequency range (10(-1) to 10(6) Hz): width of the α-relaxation (βKWW), temperature dependence of α-relaxation times (τα), fragility index (m), relation of the α-relaxation with the β-secondary relaxation, and the breakdown of the Debye-Stokes-Einstein (DSE) relationship between the structural relaxation time and dc-conductivity (σdc) at deep undercooling close to Tg. The β-relaxation, observed in the glassy as well as in the supercooled state was identified as the genuine Johari-Goldstein process, attributed to localized motions and regarded as the precursor of the α-relaxation as suggested in the coupling model. A separation of about 6 decades between the α- and β-relaxation was observed at Tg; this decoupling decreased on increasing temperature, and both processes merged at Tαβ = 295 K. The temperature dependence of the α-relaxation time, τα, was described by two Vogel-Fulcher-Tammann-Hesse equations, which intercept at a crossover temperature, TB = 290 K, close to the splitting temperature between the α- and β-relaxation. From the low temperature VFTH equation, a Tg(DRS) = 265.2 was estimated (at τα =100 s) in good agreement with the calorimetric value (Tg,onset,TMDSC = 265.6 K), and a fragility or steepness index m = 113 was calculated allowing to classify S-flurbiprofen as a fragile glass former. The α-relaxation spectra were found to be characterized by a relatively large degree of nonexponentiality (βKWW = 0.52). A breakdown of the DSE log10 σdc - log10 τ relation was observed revealing an enhancement of translational ionic motions in comparison with the orientational molecular motions as the glass transition temperature Tg is approached from above.
Isaacs’ syndrome (IS), also known as acquired neuromyotonia, is a rare neuromuscular disease, manifested by involuntary continuous motor activity.1 Although there are reports in children,2,3 IS is more frequent in adults.1 The clinical presentation can include muscle cramps, fasciculations, myokymia, and pseudomyotonia. Electromyography (EMG) remains the gold standard for diagnosis.1,4 Dysfunction of peripheral nerve voltage-gated potassium channels (VGKC) appears to be related to the development of the disease.1,3,4,5 Paraneoplastic factors also play an important role in IS.5 Anticonvulsants are the first therapeutic option.1,4,5
Infantile hepatic haemangioma (IHH) is a rare vascular tumour that is potentially lethal due to its associated complications, including heart failure, hepatic failure, hypothyroidism and abdominal compartment syndrome. The authors report a case of an asymptomatic diffuse IHH in a newborn male, which was presented as an incidental finding at the time that the patient was diagnosed with pyloric stenosis. The patient was treated with increasing doses of propranolol that were well tolerated. With the regression of the IHH by the time that the patient reached one year of age, there was a significant imagiologic improvement. Because there is no consensus on the optimal approach for the treatment of liver tumours in newborns, it is important to adopt a systematic approach. After the diagnosis of diffuse IHH has been established, the decision to initiate treatment and the therapeutic of choice is often controversial. Regular follow-up is recommended to monitor possible complications.
Several distinct conditions present as cystic or pseudocystic lesions within the spinal canal. Some of the most common spinal cystic lesions include spinal meningeal cysts, juxtafacet cysts, dermoid/epidermoid cysts, nerve sheath tumors, and syringohydromyelia. Clinical presentation is usually nonspecific and imaging characteristics are frequently overlapping, which may pose a challenging presurgical diagnosis. We provide a pictorial review of cystic intraspinal lesions and discuss the main imaging features that can aid the neuroradiologist in the differential diagnosis. First, we propose a categorization of the lesions according to their location as extradural, intradural extramedullary, and intramedullary. This is a crucial initial step in the diagnostic workup and surgical planning. Second, for each of these locations, we organize the lesions according to their etiology: congenital and developmental disorders, degenerative disorders, traumatic or postsurgical collections, infectious conditions, neoplastic lesions, and other miscellaneous disorders. Finally, we summarize the clinical highlights and MR features that provide important insights for the differential diagnosis. MR is the technique of choice in presurgical evaluation and postsurgery follow-up. It provides accurate lesion localization and characterization and, most of the times, it will allow a confident differential diagnosis.High-resolution three-dimensional T2-weighted sequences and diffusion-weighted imaging can provide important hints in specific cases. Signal correlation with T1-weighted and fat-saturated sequences allows to differentiate true cystic lesions from hemorrhage or fat tissue.
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