ABSTRACT
Background: Neuroblastoma is the most common malignancy in children younger than seven years of age and is the most frequent extracranial solid tumor that occurs in childhood. While opsoclonus-myoclonus syndrome (OMS), a paraneoplastic neurologic syndrome, affects 2-3% of children with neuroblastoma, and the percentage of mediastinal localization of the tumor is 49%. The objective of this study was to identify and characterize features of the OMS syndrome and treatments of mediastinal and non-mediastinal neuroblastoma associated with OMS. Methods: A systematic review of the literature was performed using PubMed, Medline, Web of Science, Embase and Cochrane. The search has no limit on date with the last search done on Dec 31, 2020. There is no publication restrictions or study design filters applied in the search. Results: Fifty-five out of 242 papers were identified and met our study eligibility. There were 77 cases found (28 cases had Mediastinal neuroblastoma, and 49 cases had non-mediastinal neuroblastoma). Data from trials showed that cases with mediastinal neuroblastoma who seemed to have undergone less treatment for OMS [rate ratio (RR) 0.41 (95% CI: 0.22-0.76)] had resulted in decreasing persistent neurologic symptoms [RR 0.31 (95% CI: 0.10-0.96)]. Conclusions: Children who have OMS and mediastinal neuroblastoma may be associated with more favorable clinical and biological characteristics and better outcomes than children who have OMS and non-mediastinal neuroblastoma, and they are more likely to present with a single neurological symptom at first. The OMS in mediastinal neuroblastoma might also be treated effectively through resection of the tumor followed by appropriate radiotherapy and chemotherapy, and no long-term treatments of OMS is indicated.
ABSTRACT
It is necessary to select the appropriate parameters defining a aspheric lens for coupling the light from a laser diode into the optical fiber by cap aspheric lenses. In this paper, the ant colony optimization algorithm is applied to the optimization of structural parameters of the cap aspheric lens, and the merit function defining the optimization problem and detailed design steps are given. A cap aspheric lens with center thickness of 1.1019 mm and effective focal length of 1.10331 mm is designed using a self-made MATLAB program of ant colony optimization algorithm, which can couple the light emitting from a laser diode into a single mode fiber with a diameter of 9 um, the light-emitting surface of the LD is 3 µm × 2 µm, and beam-divergence angle in the X and Y directions are ± 35° and ± 23.58°, respectively. The theoretical coupling efficiency is 89.8%, and the experiment shows that the maximum coupling efficiency and average coupling efficiency are 88.63% and 79.39%, respectively. Design and experimental results prove that the design method in this paper is feasible and effective.
ABSTRACT
The energetic stability, atomic and electronic structures of γ-graphyne and its derivatives (γ-GYs) with extended carbon chains were investigated as a function of chain length by density functional calculations in this work. The studied γ-GYs consist of hexagon carbon rings connected by linear chains with C atoms n = 0-22. We predict that the even-numbered C chains of γ-GYs consist of alternating single and triple C-C bonds (polyyne), energetically more stable than the odd-numbered C chains made of continuous C-C double bonds (polycumulene). The calculated electronic structures indicate that γ-GYs can be either metallic (odd n) or semiconductive (even n) depending on the parity of the number of C chain atoms. The semiconducting γ-GYs are predicted to have ~1.2 eV direct band gaps and 0.1-0.2 effective electron masses independent of the chain length. Thus introducing sp carbon atoms into sp (2)-based graphene provides a novel way to open up band gaps without doping and defects while maintaining small electron masses critical to good transport properties. Graphical Abstract The typical atomic model of graphyne (middle) as well as their band gaps (left) and electron density (right).
