Biological improvement of saline alkali soil reference system:A review

This work presents a reference system overview to improve the efficiency of biological improvement of saline-alkali soil developed during the last thirty years, ranging from connotation, general methods and species, soil desalination, soil structure, soil organic content, microbial flora, enzyme activity, yield and economic benefits. The reference system presented is divided into three main groups: suitable varieties, suitable cultivation measures, and a comprehensive evaluation system.There has been a lot of research on biological improvement of saline alkali soil, but these studies are very fragmented and lack a comprehensive standard system. Also, there is a lack of practical significance, particularly with regard to optimal species, densities and times of sowing for particular regions. On the other hand, the corresponding cultivation measure is very important. Therefore, a reference system plays an important role to the effect of biological improvement of saline alkali soil.

Corneal subbasal nerve fiber regeneration in myopic patients after laser in situ keratomileusis

A total of 26 myopic patients （52 eyes） underwent laser in situ keratomileusis. In vivo confocal microscopy revealed that most of the regenerated corneal subbasal nerve fibers in the comeal flap originated from the stump of corneal subbasal nerve fibers outside the ablation zone and extended towards the center of the cornea in all patients. Meanwhile, new fibers were also found to directly regenerate from deep in the stroma in some cases. Approximately 94% of regenerated corneal subbasal nerve fibers （73/78 eyes） regrew vertically into the peripheral central 6-mm circle area 1 month after surgery, 78% （28/36 eyes） grew into the central 3 6 mm area at 2 months, and 23% into the central 3-mm circle area at 3 months. In addition, there was no significant difference in corneal subbasal nerve fiber regenerative capacity between the basic fibroblast growth factor group and the 20% （vN） deproteinized extract of calf blood group. The majority of corneal subbasal nerve fiber regeneration occurred from the stump of corneal subbasal nerve fibers outside the corneal flap and the remaining growth occurred deep within the stroma.

Postoperative changes in corneal epithelial and stromal thickness profiles after SMILE in high myopic eyes

Background:To observe changes in the epithelial and stromal thickness after small incision refractive lenticule extraction(SMILE)and investigate their relationship with the different refractive error.Methods:One hundred and eighty eyes of 90 patients with a manifest refraction spherical equivalent(MRSE)of-6.36±1.53 diopters(D)were included.The eyes were assigned to the moderate myopic group(MRSE-3.00 to-6.00 D),high myopic group(MRSE-6.00 to-8.00 D)and super-high myopic group(MRSE above-8.00 D).The spectral-domain optical coherence tomography(SD-OCT)measured corneal and epithelial thickness in 17 zones preoperatively and 1,3,and 6 months postoperatively.Stromal thickness was calculated by subtracting the epithelial thickness from the total corneal thickness.The observed changes were correlated with the degree of myopia corrected.Results:MRSE showed significant differences between 3 and 6 months in the super-high myopic group(P=0.024).At 6 months,a statistically significant epithelial thickness increase was observed in the central zone(7.18%for moderate,10.23%for high,and 13.76%for super-high myopia,P<0.05 for all groups).The peripheral thickness decreased between 3 and 6 months in the high myopia and super-high myopia groups(P<0.05,respectively).A positive correlation between MRSE corrected and the postoperative epithelial thickening was observed in the central(r2=0.551,P<0.05).Compared to 1 month values,the central stromal thickness showed a decrease(3.2±4.5μm)at 3 months and an increase(4.4±4.9μm)at 6 months.The stroma thickened in moderate and high myopic groups but the thickness reduction were in super-high myopia group at 6 months paracentrally and peripherally.Conclusions:Significant thickness changes in the epithelium and stroma were detected during the 6 months after SMILE.Preliminary results suggest that epithelial and stromal thickness profile changes after SMILE may have an impact on the refractive outcome in the long-term postoperative period,especially in super-higher degrees of myopia.

Effects of organic fertilizers on organic carbon accumulation in alkalized saline soil and silage maize yield

To understand the combined effect of organic and chemical fertilizers on soil carbon emissions and carbon balance of a farmland ecosystem,this study investigated the organic fertilizer nitrogen replacing different proportions of chemical fertilizer nitrogen.The results showed that,compared to F_(100),the O_(15)F_(85) treatment increased the yield and net ecosystem productivity carbon sequestration of silage maize under mild,moderate,and severe salinization levels,as well as the contents of soil organic carbon,microbial carbon,and humin carbon,while reducing plant carbon emissions.The O_(15)F_(85) treatment did not significantly increase soil carbon emissions(CEC),but O_(30)F_(70),O_(45)F_(55) and O_(100) treatments significantly increased CEC.The soil carbon balance analysis showed that the farmland ecosystem was a“sink”for atmospheric CO_(2) under each treatment.The O_(15)F_(85) treatment produced an“excitation effect”to enhance the carbon sink effect of silage maize farmland under mild,moderate and severe salinization levels while maintaining stable production and emissions.Although the O_(100) treatment increased the carbon sink of farmland under different salinization levels,the yield was significantly reduced and did not represent practical production levels.Correlation analysis showed that soil organic carbon components and ecosystem carbon balance were closely related to soil total salt,pH and bulk density,while soil dissolved organic carbon,humus carbon components and carbon emissions were closely related to soil moisture and temperature.Therefore,the purpose of improving the carbon sink of saline-alkali land can be achieved through soil salt inhibition,soil structure remodeling and water supplement and warming regulation,which provides technical and theoretical support for reducing carbon emissions,achieving carbon neutrality and alleviating global warming.

病毒疫情期间开展角膜屈光手术的流程及防护策略

目前对病毒的防控工作取得了阶段性成效,很多地区已经复工。北京是我国首都,春节后返京人员多,入境人员较多。我们在全力做好北京疫情防控的同时,严格根据防护政策,采取科学措施避免交叉感染风险,有序、少量地开展了角膜屈光手术。现对北京同仁医院屈光手术中心实行角膜屈光手术的流程和防护策略进行介绍,以期为相关行业的医务人员提供参考。

进一步提升SMILE的视觉质量

飞秒激光小切口角膜基质透镜取出术(SMILE)是近年来利用飞秒激光实施的一种全新的治疗理念和方式。与既往利用准分子激光治疗的表层和基质角膜屈光手术相比,SMILE对于提升屈光不正患者术后视觉质量具有较为明显的效果和应用潜力。现结合国内外对于SMILE相关的前沿研究,深入阐明该术式的实际应用效果及临床前景,以期为临床安全稳步实施SMILE以及进一步提升其视觉质量提供参考。

飞秒激光时代浅谈表层角膜屈光手术的临床意义

目前是多元化角膜屈光手术的飞秒激光时代，根据眼部的生物学参数合理选择个性化手术方式值得大力提倡。在飞秒激光角膜屈光手术方式蓬勃开展占主流的当今，笔者就表层角膜屈光手术的一席之地及其临床意义做一评述，以期为临床合理应用该项技术提供参考。