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Layered rare earth hydroxides are new classes of functional materials. In this study, a layered La(OH)2NO3 compound having both ion-exchange capacity and non-linear optical property was studied by solid-state nuclear magnetic resonance (SSNMR) spectroscopy. The quadrupolar Carr-Purcell-Meiboom-Gill sequence (QCPMG) was used to acquire 139La SSNMR sub-spectra with variable offsets, from which the ultrawide-line spectrum was reconstructed by co-addition after applying a filtering function. The ultrawide-line spectrum consisted of both center and satellite transition line shapes, which were also simulated with the QUEST software. The 139La CQ and ηQ values measured by SSNMR experiments agreed well with those calculated with the Cambridge Sequential Total Energy Package (CASTEP). The 139La SSNMR results unambiguously indicated that the layered La(OH)2NO3 compound studied belongs to a non-centrosymmetric space group of P21.

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This letter addresses lightning surge propagation on a vertical conductor connected to the earth via a ground electrode. As the vertical conductor does not support the TEM mode of wave propagation, surge propagation is characterized with time- and position-variant surge impedance and attenuation coefficient of current. The reflection of a lightning surge at the ground then is addressed with the approach similar to the travelling wave theory. Expressions of the reflected surge excited by the current with a ramp or an arbitrary waveform are derived. Note that the reflected surge consists of two components with different attenuation rates. The traditional reflection coefficient is not applicable to the grounded vertical conductor. The results are numerically validated with the finite-difference time domain and partial element equivalent circuit methods. [ABSTRACT FROM AUTHOR]

The previous published data on the association between STK15 F31I and V57I polymorphisms and cancer risk remained controversial. Hence, we performed a meta-analysis to investigate the association between cancer susceptibility and STK15 F31I (42,315 cases and 50,542 controls from 62 studies) and V57I polymorphisms (12,891 cases and 17,391 controls from 18 studies) in different inheritance models. Overall, significant association was observed between F31I and cancer risk when all the eligible studies were pooled into the meta-analysis (recessive model: OR = 1.14, 95 % CI = 1.06-1.24; AA vs. TT: OR = 1.12, 95 % CI = 1.02-1.24; A vs. T: OR = 1.05, 95 % CI = 1.01-1.09). In the further stratified and sensitivity analyses, for STK15 F31I, significantly increased breast cancer (recessive model: OR = 1.16, 95 % CI = 1.02-1.33; AA vs. TT: OR = 1.16, 95 % CI = 1.01-1.33) and ovarian cancer (dominant model: OR = 1.20, 95 % CI = 1.07-1.34; TA vs. TT: OR = 1.19, 95 % CI = 1.06-1.34; A vs. T: OR = 1.15, 95 % CI = 1.05-1.26) risk was found among Caucasians, and significantly decreased lung cancer risk was found among Caucasians (recessive model: OR = 0.65, 95 % CI = 0.49-0.87; AA vs. TT: OR = 0.65, 95 % CI = 0.49-0.88). For V57I polymorphism, significant decreased breast cancer risk was found among Caucasians (recessive model: OR = 0.76, 95 % CI = 0.61-0.95; AA vs. GG: OR = 0.75, 95 % CI = 0.60-0.94; A vs. G: OR = 0.92, 95 % CI = 0.86-0.98). In summary, this meta-analysis suggests that STK15 F31I polymorphism is associated with increased breast cancer and ovarian cancer risk among Caucasians, F31I polymorphism is associated with decreased lung cancer risk among Caucasians, and V57I polymorphism is associated with decreased breast cancer risk among Caucasians. [ABSTRACT FROM AUTHOR]

Chuanxiong Rhizoma is a well-known Sichuan-specific herbal medicine. Its original plant, Ligusticum chuanxiong, has been cultivated asexually for a long time. L. chuanxiong has sexual reproductive disorders, which restricts its germplasm innovation. However, there is little research on the reproductive system of L. chuanxiong. This study is based on a comparative anatomical research approach, using morphological dissection, paraffin sectioning, staining and compression, and combined with scanning electron microscopy technology, to observe and compare the flowers, fruits, and seeds at various stages of reproductive growth of L. chuanxiong and its wild relative L. sinense. The results showed that the meiosis of pollen mother cells is abnormal in L. chuanxiong anthers, and the size and number of microspores are uneven and inconsistent in the tetrad stage. tapetum cells are not completely degenerated during anther development. During the pollen ripening stage, there are fine cracks in the anther wall, while most anthers could not release pollen normally. The surface of mature pollen grains is concave and partially deformed, and the pollens are all inactive and cannot germinate in vitro. The starch, polysaccharides, and lipids in the pollen were insufficient. The filaments of L. chuanxiong are short at the flowering stage and recurved downward. Double-hanging fruits were observed in the fruiting stage, being wrinkled; with shriveled seeds. Compared with L. sinense at the same stage, the anthers of L. sinense developed normally, and the pollen grains are vigorous and can germinate in vitro. The double-hanging fruits of L. sinense are full and normal; at the flowering period, the filaments are long and erect, significantly higher than the stigma. Mature blastocysts are visible in the ovary of both L. chuanxiong and L. sinense, and there is no significant difference in stigmas. The conclusion is that during the development of L. chuanxiong stamens, the meiosis of pollen mother cells is abnormal, and tetrad, tapetum, filament and other pollen structures develop abnormally. L. chuanxiong has the characteristic of male infertility, which is an important reason for its sexual reproductive disorders.