Room-temperature lasing from fluorene thin-film crystals densely doped with anthracene.
The potential for room-temperature lasing in densely doped organic crystals has been examined using (fluorene)0.8-(anthracene)0.2 thin crystals fabricated in a narrow gap between two quartz plates. An excitation-intensity dependence study confirms that the system shows spectral line narrowing, a super linear increase of the narrow line above threshold excitation intensity, and laser cavity modes. These results indicate that lasing has been observed in the densely doped organic crystal, which contains in-plane cavities with a length of approximately 100 μm.
Anthracene Crystals Under Intensive Optical Pumping
Abstract The fluorescence of a number of anthracene crystals has been studied over a wide range of nitrogen laser optical pumping. The conditions for the separate study of light generation in the plane-parallel anthracene plates and nonlinear fluorescence quenching due to exciton-exciton annihilation have been found. The threshold of generation I n (l) and quenching constant k ss have been found to be substantially dependent on the structural perfection of crystals. The values of I n (1) and K ss are reduced to 4.1019 cm−2 sec−1 and ∼ 10−9 cm3 sec−1 respectively in the most perfect subliminated plates. The decrese in the quenching constant is connected with the nontrivial influence of lattice defects on the process of exciton-exciton annihilation.
Familial Cortical Myoclonic Tremor and Epilepsy, an Enigmatic Disorder: From Phenotypes to Pathophysiology and Genetics. A Systematic Review
Background Autosomal dominant familial cortical myoclonic tremor and epilepsy (FCMTE) is characterized by distal tremulous myoclonus, generalized seizures, and signs of cortical reflex myoclonus. FCMTE has been described in over 100 pedigrees worldwide, under several different names and acronyms. Pathological changes have been located in the cerebellum. This systematic review discusses the clinical spectrum, treatment, pathophysiology, and genetic findings. Methods We carried out a PubMed search, using a combination of the following search terms: cortical tremor, myoclonus, epilepsy, benign course, adult onset, familial, and autosomal dominant; this resulted in a total of 77 studies (761 patients; 126 pedigrees) fulfilling the inclusion and exclusion criteria. Results Phenotypic differences across pedigrees exist, possibly related to underlying genetic differences. A “benign” phenotype has been described in several Japanese families and pedigrees linked to 8q (FCMTE1). French patients (5p linkage; FCMTE3) exhibit more severe progression, and in Japanese/Chinese pedigrees (with unknown linkage) anticipation has been suggested. Preferred treatment is with valproate (mind teratogenicity), levetiracetam, and/or clonazepam. Several genes have been identified, which differ in potential pathogenicity. Discussion Based on the core features (above), the syndrome can be considered a distinct clinical entity. Clinical features may also include proximal myoclonus and mild progression with aging. Valproate or levetiracetam, with or without clonazepam, reduces symptoms. FCMTE is a heterogeneous disorder, and likely to include a variety of different conditions with mutations of different genes. Distinct phenotypic traits might reflect different genetic mutations. Genes involved in Purkinje cell outgrowth or those encoding for ion channels or neurotransmitters seem good candidate genes.