Progress on research and mitigation of wind-blown sand risk in Dunhuang Singing Sand Mountain and Crescent Spring Scenic area,China

The Singing Sand Mountain and Crescent Spring Scenic Spot in Dunhuang,Northwest China is a world-renowned desert attraction that is also an integral component of the Dunhuang UNESCO Global Geopark.This scenic area underwent a 30-year transformation,i.e.,from a severe sand risk with spring water threatened by sand burial due to dune deformation,to restoration of the original sand flow field and mitigation of the sand burial problem.The current paper summarizes the research on the intensive monitoring of the dynamic change of star dunes near the spring,observation of wind and sand flow movement,and then restoring the harmonic vibration of the sand particles(singing sand)that were previously silenced.The existing and prospective impacts of anthropogenic and natural forces on the deformation of the sand dunes are investigated by integrated methods,guiding the implementation of mitigating measures with significant ameliorative effects.Contrast to common sand control practices that aim to reduce wind speed and stop blown sands,our research highlights the importance of maintaining the natural wind flow field in stabilizing surrounding dunes.These mitigation measures consist of removing excessive vegetation and newly constructed buildings to recover the original wind flow field and sand transport activity.Such research and mitigation efforts ensure the scientific protection and restoration of the special desert landform,and contribute to the mutual enhancement of the conservation and exploitation of this desert scenic spot and similar sites.

Quantitative analysis on the dynamic characteristics of megadunes around the Crescent Moon Spring, China

The Crescent Moon Spring is a precious natural heritage. However, the dynamic characteristics of megadunes around the Crescent Moon Spring are not well known. This paper quantitatively studied the character- istics and changes of megadunes around the Crescent Moon Spring by interpreting aerial photographs taken in 1985 and 2004 and analysing the dune crestlines and the wind data collected from 2011 to 2012. Results revealed that pyramid dunes were formed by a complex wind regime. The Crescent Moon Spring was not buried by shifting sands because of the stable wind regime and relative stability of pyramid dunes. The crestlines of the dunes around the spring moved northward between 1985 and 2004. The south-facing slip faces were also exposed to wind ero- sion, whereas the other faces were under deposition, thus indicating that the southerly wind was relatively en- hanced. Limiting the scale of tall windbreaks and architectures in the Dunhuang oasis at the north of the spring was necessary to maintain the dynamic equilibrium of the wind regime and sand transport.

Morphological variation of star dune and implications for dune management: a case study at the Crescent Moon Spring scenic spot of Dunhuang, China

Aerial photographs and 3-D laser scans of a 90-m high star dune at the Crescent Moon Spring scenic spot in Dunhuang,China,are used to investigate the changes in dune morphology on timescales from months to decades.The result revealed that relative-equilibrium airflow strength in three wind directions of northeast,west and south was an important condition for the stability of star dunes with limited migration.Transverse and longitudinal airflows exerted a crucial impact on variation processes of star dune morphology.Controlled by transverse airflows,the easterly winds,the east side was dominated by wind erosion;and strong deposition occurred on the south-south-east arm with a maximum deposition rate of 0.44 m/a in the 46-a monitoring period,causing the east side becoming steep and high.Controlled by longitudinal airflows,the westerly winds,the west-north-west side was mainly eroded and the north arm migrated from west to east with a rate of 0.30 m/a,causing the dune slope becoming gentle and elongate.The local air circulation(southerly winds)exerted a significant impact on the development process of the star dune.Due to the influence of human activities,the south side present surface processes from a concave profile to a convex profile in 46 a,which is a potential threat to the Crescent Moon Spring.The results indicate that rehabilitating the airflow field at most is a crucial strategy to the protection of Crescent Moon Spring from burial.Opening up the passage of easterly,westerly and southerly winds through intermediately cutting the protection forest,demolishing the enclosed wall and changing the pavilion into a porous pattern have been suggested to protect the Crescent Moon Spring from burial.

Experimental study on modulational instability and evolution of crescent waves

A series of experiments on the instability of steeP water wave trains in water with finite water depths and infinite water depths in a wide wave basin were performed. It was found that under the coupled development of modulational instability and class-Ⅱ instability, the initial two-dimensional steep wave trains evolved into three＇dimensional crescent waves, followed by the occurrence of disordered water surfaces, and that the wave energy transferred to sidebands in the amplitude spectrum of the water surface elevation. The results also show that water depth has a significant effect on the growth of modulational instability and the evolutiin of crescent waves. The larger the water depth, the more quickly the modulational instability suppresses class-II instability.

Bacterial diversity in the sediment of Crescent Moon Spring,Kumtag Desert,Northwest China

Desert lake, a unique oasis in desert ecosystems, harbours different bacterial communities. Thus, it is considered as a hub of bacterial diversity. In this study, bacterial diversity in the sediment of Crescent Moon Spring, Kumtag Desert, Northwest China was analyzed using high-throughput amplicon pyrosequencing analysis. The sequences of the most abundant OUTs （Operational Taxonomic Units） in the sediment of Crescent Moon Spring were compared with the sequences of those most abundant OUTs of various origins from NCBI GenBank database to detect the origins of bacteria in the sediment of Crescent Moon Spring. Also, bacterial compositions between sediment of Crescent Moon Spring and other desert and lake ecosystems （including desert lakes） worldwide were compared using cluster analysis to determine the possible factors affecting bacterial compositions. In total, 11,855 sequences were obtained and 30 phyla were identified. At the phylum level, the dominant phylum was Proteobacteria with α-Proteobacteria being the first dominant class and the second dominant phylum was Planctomycetes. Our finding that α-Proteobacteria being the first dominant class of Proteobacteria and Planctomycetes being the second dominant phyla are somewhat contradictory with reports from other desert lake sediments. This difference could be resulted from water hydration and conductivity, as well as oligotrophic conditions of Crescent Moon Spring. At the genus level, Rhodobacter, Caldilinea, Planctomyces, and Porphyrobacterwere the dominant genera in the sediment of Crescent Moon Spring. Comparisons on sequences of the most abundant OUTs （including OTU3615, OTU6535, and OTU6646） between sediment of Crescent Moon Spring and various origins from NCBI GenBank database indicate that the origins of bacteria in the sediment of Crescent Moon Spring are likely from the underground water. Furthermore, cluster analysis on comparisons of bacteria compositions between sediment of Crescent Moon Spring and other desert and lake ecosystems （including desert lakes） worldwide shows that at regional scales, bacterial compositions may be mainly affected by geographical patterns, precipitation amounts, and pH values. Collectively, our results provide new knowledge on the bacterial diversity in desert lake ecosystems.

Grain size distribution at four developmental stages of crescent dunes in the hinterland of the Taklimakan Desert,China

Although scientists have performed many studies on crescent （barchan） dunes in the Taklimakan Desert,few studies reported the changes in grain size at different development stages of crescent dunes.In order to evaluate the changing trends of surface sediment grain size with dune development,we investigated the grain size characteristics at four developmental stages （oval sand pile,shield dune,incipient crescent dune and mature crescent dune） of crescent dunes by measuring the morphology of sand dune and observing the near-surface wind regime.The dunes have developed in a wide inter-dune corridor between high compound longitudinal ridges in China＇s Taklimakan Desert.The surface sediments at four developmental stages of the crescent dunes were primarily composed of fine sands,followed by very fine and medium sands.Mean grain sizes ranged from 2.8 to 3.1 φ,with a unimodal distribution.The sands were moderately well-sorted,their distribution varied from platykurtic to very platykurtic,and symmetrical or skewed towards the fine particles.From oval sand piles through shield and incipient crescent dunes to mature crescent dunes,incipient grain size gradually increased,particles became finer,sorting became better,kurtosis and skewness increased.Grain sizes on the surface layer became coarser upwards from the toe of the windward slope and then became finer towards the bottom of the leeward slope.We found that the coarsest particles at different positions at the four developmental stages were different.The coarsest particles were distributed at the top of the oval sand piles and shield dunes,versus at the middle of the windward slope of the incipient and mature crescent dunes.Correlations between the mean grain size and other grain size parameters showed that as mean grain size became finer,sorting became better and kurtosis became wider,but skewness changed only slightly.In addition,grain size variation in the surface sediments correlated with the movement speed of the dunes in the study area.In the open ground among tall-complex longitudinal ridges in the hinterland of the Taklimakan Desert where aeolian environment is characterized by comparatively strong wind and unsaturated sand flow,faster dune movement corresponded to coarser grain size.

Accuracy of crescent sign on ocular ultrasound in diagnosing papilledema

AIM To study the usefulness of orbital ultrasonography in the diagnosis of papilledema.METHODS Fifty patients who were referred to the neurophthalmology clinic and clinically suspected to have papilledema were selected. Thorough, clinical examination with slitlamp biomicroscopy and visual acuity assessment was done. These patients underwent ultrasonography to demonstrate the crescent sign. The patients were further evaluated with the neurologist and magnetic resonance imaging(MRI) thus confirming the diagnosis of papilledema. The results of our ultrasonographic evaluation were correlated with final diagnosis after thorough clinical evaluation, imaging and the neurologist's opinion.RESULTS Out of 50 patients diagnosed having papilledema on MRI, 46(92%) showed crescent sign on B scan ultrasonography. Headache was most common presenting complaint in 47(94%) and idiopathic intracranial hypertension was most common underlying cause of papilledema in 30(60%) cases.CONCLUSION"Crescent sign" seen on ultrasonography is a sensitive tool for diagnosis of papilledema. It is cost effective, less cumbersome and effective tool to differentiatebetween papilledema and pseudo papilledema before subjecting the patients to costly investigations like MRI. A positive crescent sign should always be followed by MRI to find out the cause of papilledema.

Evolution of crescent-shaped sand dune under the influence of injected sand flux:scaling law and wind tunnel experiment

This paper studies the evolution of crescent-shaped dune under the influence of injected flux. A scaling law and a wind tunnel experiment are carried out for comparison. The experiment incorporates a novel image processing algorithm to recover the evolutionary process. The theoretical and experimental results agree well in the middle stage of dune evolution, but deviate from each other in the initial and final stages, suggesting that the crescent-shaped dune evolution is intrinsically scale-variant and that the crescent shape breaks down under unsaturated condition.

A Restrained Iran:Consolidating the Shiite Crescent

The Arab Spring is supposed to be the Arab world’s great changes and turmoil,but Iran has repeatedly become the focus in the following changes.Whether it is in the Syrian civil war,or strikes against ISIS,or the Qatar crisis,Iran repeatedly appeared.There are different attitudes towards Iran’s behavior.The Trump administration holds the opinion that Iran is

Antineutrophil cytoplasmic antibodies crescentic allograft glomerulonephritis after sofosbuvir therapy

Antineutrophil cytoplasmic antibodies(ANCA) are well known to be associated with several types of vasculitis, including pauci-immune crescentic glomerulonephritis, a form of rapid progressive glomerular nephritis(RPGN). ANCA vasculitis has also been reported after administration of propylthiouracil, hydralazine, cocaine(adulterated with levimasole), allopurinol, penicillamine and few other drugs. All previously reported cases of drug-associated ANCA glomerulonephritis were in native kidneys. Sofosbuvir is a new and effective drug for hepatitis C virus infection. Here, we report a case of ANCA vasculitis and RPGN following sofosbuvir administration in a kidney transplant recipient. It also represents the first case of drug-associated ANCA vasculitis in a transplanted kidney. Further drug monitoring is necessary to elucidate the degree of association and possible causal effect of sofosbuvir and perinuclear ANCA vasculitis.

Two Cases of ANCA-negative Pauci-immune Crescentic Glomerulonephritis in Pregnant or Maternal Women

Here two cases of renal failure occurring in pregnancy were reported,with biopsy-proven pauci-immune crescentic glomerulonephritis at postpartum.It is most rare that pauci-immune crescentic glomerulonephritis as the cause of renal failure in pregnancy.Their renal function could remain stable for some time due to timely and appropriate treatment.Therefore,the pregnant and maternal who have the performance of renal impairment should be closely tracked their blood pressure,urinary protein and renal function,if necessary,execute renal biopsy,for a clear and accurate pathological diagnosis is of great significance to grasp the opportunity of treatment.But the long-term prognosis is still poor.

表现为新月体性肾小球肾炎的纤维性肾小球病

34岁女性患者,临床表现为水肿、高血压、大量蛋白尿、镜下血尿、低蛋白血症、血清肌酐升高。肾活检病理光镜示大量新月体形成伴袢坏死,电镜示上皮下、基膜内及系膜区杂乱分布的纤维样结构(直径12~30 nm)沉积,肾小球免疫组化染色DNAJ热休克蛋白家族成员B9(DNAJB9)阳性,诊断为DNAJB9相关纤维性肾小球病、新月体性肾小球肾炎。给予利妥昔单抗、吗替麦考酚酯、糖皮质激素等治疗,获得了较好的临床疗效。

组织工程治疗股骨头坏死软骨下分离的适用技术

背景:股骨头坏死出现新月征是病情进程的“分水岭”,修复和稳定骨-软骨界面对阻止病情继续进展和预防股骨头塌陷尤为重要。利用组织工程学同步修复、整合骨-软骨界面具有潜在优势。目的:综述探讨解决股骨头坏死软骨下分离的潜在适宜技术。方法:检索1970年1月至2023年4月PubMed、Web of Science及中国知网、万方数据库中发表的相关文献,英文检索词:“Femoral head necrosis,Avascular necrosis of femoral head,Osteonecrosis of femoral head”等,中文检索词:“股骨头坏死,软骨下骨,软骨,软骨与软骨下骨整合”等,最终纳入114篇文献进行综述分析。结果与结论:①结构缺陷、缺血缺氧环境、炎症因素和应力集中可能造成股骨头坏死软骨下分离现象,软骨下骨分离会造成塌陷进展,并且可能与保髋手术失败相关,利用组织工程支架实现支架与骨-软骨界面的整合是治疗股骨头坏死软骨下分离的潜在方法之一。②目前的文献研究表明,多相、梯度支架和复合材料在促进骨、软骨细胞黏附与增殖,骨软骨基质的沉积方面均有提升,有助于支架与骨-软骨界面的整合,对治疗股骨头坏死软骨下分离有参考价值。③通过对支架表面进行修饰可以提高与界面整合的效率,但有各自不同的优缺点,提供不同环境的支架能够诱导同种间充质干细胞差异分化,有助于不同界面之间的整合。④未来有望应用于股骨头坏死软骨下分离的支架应为复合材料,具有梯度化和差异化的仿生结构,通过表面修饰和干细胞加载促进骨-软骨界面与支架的整合以实现治疗目的,但仍需进一步研究验证,而支架的降解速率与修复进度同步和不同界面之间的稳定性是未来需要解决的主要问题。

原发性IgA肾病伴弥漫性新月体形成的临床特点及预后分析

目的了解弥漫性新月体IgA肾病(CIgAN)患者的临床病理特征和预后。方法2007年7月至2022年7月经肾活检确诊为弥漫性新月体IgAN患者33例,分析临床及病理资料。随访时间超过6个月患者22例纳入随访队列。结果33例患者中男18例(55%),女15例(45%),肾活检时年龄为36(21.5,51)岁,血清肌酐(Scr)153(92,271)μmol/L,新月体百分比为62.5%(54.2%,66.7%),其中细胞纤维性新月体为(26.1%±16.5%)。13例患者有前驱呼吸道感染。22例患者平均随访时间为25(8,72)个月。10例(46%)患者进展至复合肾脏结局,其中8例(36%)发展为终末期肾脏病。多因素Cox回归结果显示,肾活检时Scr是复合肾脏结局的独立危险因素,而新月体的百分比与复合肾脏结局无关。受试者工作特征曲线结果表明,即使接受免疫抑制剂治疗,肾活检时Scr浓度大于149μmol/L的弥漫性新月体IgAN患者预后不良风险仍然较高。结论弥漫性新月体IgAN病情进展快,预后差,尤其是肾活检时Scr浓度大于149μmol/L的患者。新月体类型以细胞纤维性新月体为主。肾活检时血清Scr浓度是弥漫性新月体IgAN患者eGFR下降≥50%或ESKD的独立危险因素,而新月体的百分比与患者预后无明显相关性。

MiR-29b expression is altered in crescent formation of HSPN and accelerates AngⅡ-induced mesangial cell activation

Background MicroRNA-29b(miR-29b)has been suggested to possess pro-inflammatory activity,which can partially be explained by the repression of tumor necrosis factor alpha protein three antibody(TNFAIP3).Meanwhile,it also promotes thyroid cell proliferation via Smad signaling pathways.The present study aimed to elucidate the role of miR-29b in Henoch Sch(o)nlein purpura nephritis(HSPN)and its underlying molecular mechanism in angiotensinⅡ(AngⅡ)-induced human glomerular mesangial cell(HGMC)activation.Methods We evaluated miR-29b expression in 35 HSPN renal tissues based on crescent formation,glomerular sclerosis,interstitial fibrosis,thrombosis formation and capillary loop necrosis.Meanwhile,HGMCs were cultured,treated with AngⅡand then transfected with LV-hsa-miR-29b-1 to induce miR-29b overexpression or LV-hsa-miR-29b-3p-inhibition to inhibit miR-29b expression.Finally,we examined the effects of miR-29b on cell proliferation and release of inflammatory mediators.Results We observed that miR-29b expression was significantly higher in the crescent group than in the no crescent group.MiR-29b overexpression induced the release of intercellular adhesion molecule-1,interleukin-1β(IL-1β),IL-6,IL-8,the increase of CyclinA2,CyclinD 1,and cell proliferation.It also could inhibit the expressions of TNFAIP3 and NF-kappa-B-repressing factor(NKRF).Correspondingly,miR-29b inhibition produced the opposite effects and increased the expression of TNFAIP3 and NKRF.Conclusion MiR-29b expression is altered in crescent formation of HSPN and accelerates AngⅡ-induced mesangial cell proliferation and release of inflammatory mediators.

Infective Endocarditis-induced Crescentic Glomerulonephritis Dramatically Improved after Removal of Vegetations and Valve Replacement

Infective endocarditis （IE） is associated with poor prognosis and higher mortality. IE-induced glomerulonephritis, especially crescentic glomerulonephritis （IE-CGN） with renal dysfunction, is an independent risk factor for mortality For the treatment of IE-CGN, many therapeutic strategies including antibiotics alone, antibiotics combined with corticosteroid, immunosuppressive agents, plasmapheresis, or cardiac surgery have been applied and obtained various results.C21 Here, we reported a case of CGN with progressive renal failure secondary to IE in which the renal function was dramatically improved by the treatment of surgical valve replacement and antibiotics.

伴不同比例新月体IgA肾病患者的临床病理特征及预后分析

目的探讨不同比例新月体IgA肾病(IgA nephropathy,IgAN)患者的临床病理特征以及新月体对预测肾脏结局的价值。方法收集2019年1月1日至2020年12月31日期间在武汉大学人民医院经肾活检确诊为原发性IgAN且符合纳排标准的237例患者的临床、病理以及随访资料。将患者按有无新月体形成分为新月体组和无新月体组,其中新月体组根据病变累及肾小球的比例进一步分为新月体比例<10%、10%≤新月体比例<25%、新月体比例≥25%三个亚组,比较各组间患者临床、病理特征及预后的差异。终点事件为患者基线血肌酐翻倍或进入终末期肾病或死亡。采用Kaplan-Meier生存曲线评估患者肾脏累积存活率的差异,构建Cox风险回归模型分析不同比例的新月体在预测IgAN疾病进展及预后中的价值。结果237例IgAN患者中新月体组134例(56.54%),其中新月体比例<10%组有48例,10%≤新月体比例<25%有56例,新月体比例≥25%有30例。(1)临床特征:对于具有新月体的患者,随着新月体比例的增大,患者的收缩压、舒张压、血肌酐、尿素氮、总胆固醇、24 h尿蛋白定量、使用激素、免疫抑制剂的比例逐渐升高,尿隐血程度逐渐加重,而血红蛋白、白蛋白、估算肾小球滤过率(estimated glomerular filtration rate,e GFR)、血清IgG水平则逐渐降低(P<0.05)。(2)病理特征:与无新月体组相比,新月体组患者肾脏病理改变程度较严重,表现为系膜细胞增生(M1)、内皮细胞增生(E1)、节段性硬化(S1)、肾小管萎缩/间质纤维化(T1/2)的比例更高,间质炎细胞浸润程度、肾组织中补体C3沉积程度更严重,而且新月体比例越高的组出现细胞性新月体、纤维细胞性新月体、纤维性新月体、大新月体的比例也随之增大(P<0.05)。(3)影响新月体形成的相关因素:通过多因素Logistic回归分析发现,肾脏C3沉积和24 h尿蛋白定量是IgAN新月体形成的独立危险因素,而血红蛋白是其保护因素(P<0.05)。(4)Kaplan-Meier曲线分析结果显示,无新月体组和新月体组患者肾脏累积存活率组间比较差异有统计学意义(P=0.032);而且新月体比例≥25%组的肾脏累积存活率显著低于新月体比例<10%组和10%≤新月体比例<25%组,组间比较差异有统计学意义(P<0.001)。(5)单因素COX回归模型结果显示,血红蛋白、24 h尿蛋白定量、血肌酐、血尿酸、eGFR、新月体比例、E1、T1/2与发生肾脏终点事件有关(P<0.05),但经多因素校正后,仅24 h尿蛋白定量、血肌酐、T1/2、新月体比例≥25%是影响IgAN疾病进展和预后的独立危险因素(P<0.05)。结论IgAN患者随着新月体比例的升高,临床表现及肾脏病理改变更为严重,肾脏预后也更差。新月体比例≥25%是肾脏不良结局的一个独立预测因子,对于少量新月体形成患者,早期进行干预可以增加临床获益。

Clinical spectrum of diffuse crescentic glomerulonephritis in Chinese patients

Objective To investigate retrospectively the incidence, distribution of primary disease and clinicopathologic characteristics of diffuse crescentic glomerulonephritis (DCGN) in Chinese patients.Methods One hundred and seventy-two consecutive patients diagnosed as having DCGN out of 9828 cases of non-transplanting renal biopsies over sixteen years, were studied. DCGN is categorized into three types according to immunopathologic characteristics. The incidence of this disease, its primary diseases, clinical characteristics and serum antineutrophil cytoplasmic antibodies (ANCAs) were analyzed.Results The distribution of patients among the three classifications was 8. 7% type Ⅰ , 68. 6% type Ⅱ and 22. 7% type Ⅲ. Clinically, the majority of patients (69.8%) presented rapidly progressive glomerulonephritis (RPGN), but 30. 2% manifested a chronic nephritic syndrome or chronic renal failure. In terms of related conditions, 93% were anemic, 61. 6% had hypertension, 50. 6% oliguria, 45.3% nephrotic syndrome, 43% uremic syndrome and 39.5% displayed gross hematuria. Those patients who were positive in serum for ANCAs had predominantly type Ⅲ DCGN. Two cases with anti-GBM-antibody crescentic glomerulonephritis and three with lupus nephritis were also positive for ANCAs in serum.Conclusion DCGN is not rare in Chinese patients. A majority of patients in our study presented with RPGN, but 30. 2% manifested a chronic renal failure. Lupus patients with DCGN that were positive for ANCAs had more severe vasculitic lesions.

敦煌月牙泉域地下水系统水文地球化学特征分析

选择河西走廊西端的月牙泉域作为研究对象,通过样品采集测试,对研究区内的水化学特征、环境同位素和水文地球化学过程进行了系统分析。结果表明:大气降雨(包括冰川融水)形成的出山河水是区内潜水的主要补给来源,二者存在密切的成因联系,局部地区受断裂构造或越流影响并受祁连山前深部地下径流侧向补给;党河灌区地下水的蒸发作用微弱,以人工开采为主要排泄方式,其他浅层地下水以蒸发为主要排泄项;地下水化学成分的演化受到碳酸和硅酸盐岩溶滤作用的影响;岩盐、石膏和硅酸盐岩的溶解作用、方解石和白云岩的沉淀作用以及蒸发作用是控制地下水盐分的主要因素,且在流域水循环过程中存在不同程度的混合作用。研究结果可为月牙泉生态保护与恢复提供科学依据。