Changes in ocular surface status and dry eye symptoms following femtosecond laser-assisted cataract surgery

AIM: To observe the changes in ocular surface and the dry eye symptoms following femtosecond laser-assisted cataract surgery(FLACS). METHODS: Patients with no eye signs or symptoms in Guangzhou Aier Eye Hospital between October 2017 and September 2018, who underwent FLACS and intraocular lens(IOL) implantation for age-related cataract were enrolled. Tear film stability assessed with OCULUS Keratograph 5 M, Schirmer’s I test(SIT), and corneal fluorescein staining(CFS) were evaluated before and after surgery at 1 d, 1 wk, 1, and 3 mo in order. Ocular Surface Disease Index scores(OSDI) and Subjective Symptom Questionnaires(SSQs) were recorded at the same time point.RESULTS: Thirty-eight eyes of 38 patients were enrolled. The noninvasive tear film break-up time(first break-up time and average break-up time) decreased in a peak at the 1 wk visit, and then increased to basic levels at 1 mo. The tear meniscus height(TMH) increased transiently at 1 d, and declined in the following 3 mo visits. The SIT had a transient increase at 1 d(P=0.357) and a decrease at 1 wk and 1 mo(both P<0.05) but returned to the preoperative levels at 3 mo after surgery(P=0.062). CFS scores were significantly improved compared with those before surgery, and had a statistical difference(P<0.05). OSDI scores and SSQs after surgery were obviously higher, and had a statistical difference(P<0.001) but didn’t return to the basic level by 3 mo. CONCLUSION: Dry eye signs and symptoms can occur immediately following FLACS and have a peak severity on day 7 postoperatively. Most signs of dry eye can return to preoperative basic levels within 3 mo postoperatively. However, all cases can not recover from CFS and dry eye symptoms at 3 mo postoperatively.

Sources of rare earth elements REE+Y(REY)in Bayili Coal Mine from Wensu County of Xinjiang,China

By analyses on the trace elements of coals,host-rocks and wall-rocks,this study aims to trace the sources and evaluate the utilization prospects of REE+Y(REY)in coals from Bayili Coal Mine(Wensu,Xinjiang,China).The distribution patterns of REY in the coals are divided into two groups,flat-type and heavy REE-enrichment type(H-type).The REY of the former was mainly from the gneisses of the basement of the coal-bearing basin,and that of the later was partly from hydrothermal solution.The host-rocks show two types of REY patterns,middle REE-enrichment type(M-type)and H-type,which are due to the injection of REY from acid terrestrial water and hydrothermal solution,respectively.Almost all the coal samples are plotted into the promising area on the diagram of percentage of critical elements(REY_(def,rel))vs ratio of sum of critical elements to the sum of excessive elements(C_(outl))and half of the coal samples have high contents of Ga closing to the cut-off grade of Ga deposit as by-product,which indicate that the REY and Ga in Bayili Coal Mine are of utilization prospects as by-product.

Vegetation and Environment History for the Past 14 000 yr BP from Dingnan, Jiangxi Province, South China

A Late Pleistocene-Holocene pollen, phosphorus, and charcoal record was reconstructed from a peatland in southern Jiangxi Province in southern China. The area today has a mountainous and rolling landscape with villages, small towns, and agriculture dominated by rice paddies, vegetable, and fruit gardens, as well as areas of secondary forest and pine re-afforestation. The record opens before 14 300 yr BP, with Alnus woodland dominating the wetland areas and with an open Quercus woodland on the surrounding slopes. The forest area becomes more complex from approximately 12 800 yr BP and further from 9 000 yr BP. At approximately 6 000 yr BP, there is evidence of clearing and, by 4 500-4 000 yr BP, a complete collapse in the wetland Alnus and terrestrial forest as the low-lying areas are converted to rice production. For much of the record, the occurrence of fire around the site was low, although there is evidence of regional fires. Fire was used as a tool in clearing and then used in the annual cycles of stubble burning after rice harvest. Nutrient levels, as reflected by total phosphorus in the sediment, seem to be closely related to forest changes and high values in the surface layers probably result from land-management techniques associated with agriculture. Therefore, human impact greatly altered forest cover, fire frequency, and nutrient dynamics; this has been evident for approximately 6 000 yr BP and then intensities towards the present day.

带隙可调的超结构梁：数值和实验研究（英文）

目的:1.研究晶格常数、预应力和弹簧刚度对超结构梁带隙的影响,优化结构并形成伪禁带或低频且宽的禁带;2.通过实验验证伪禁带的存在性、排列对带隙的影响以及缺陷对带隙的影响等。创新点:1.通过预应力调节超结构梁的带隙特征,并可以形成伪禁带;2.通过排列不同弹簧振子构成宽频禁带和宽频伪禁带。方法:1.通过有限元软件模拟预应力、弹簧刚度和晶格常数等参数对该超结构梁带隙的影响情况;2.设计合适的参数并进行结构优化,使得该结构的带隙宽,频率低,且易于实验实现;3.在实验中通过替换弹簧、改变弹簧间距和施加轴向拉力分别研究弹簧刚度、晶格常数和预应力的影响,并通过移除部分弹簧和同时布置不同弹簧的方式研究缺陷和排列对带隙的影响。结论:1.该结构存在一条局域共振禁带和多条布拉格散射禁带;通过调节预应力、弹簧刚度和晶格常数等可以有效地控制带隙特征。2.在特定条件下可以形成宽频伪禁带;通过排列不同弹簧振子可以达到拓宽禁带、形成宽频伪禁带的效果。3.缺陷对布拉格散射禁带的影响较大,对局域共振禁带的影响较小。