Impact of mica on geotechnical behavior of weathered granitic soil using macro and micro investigations

The micaceous weathered granitic soil(WGS)is frequently encountered in civil engineering worldwide,unfortunately little information is available regarding how mica affects the physico-mechanical behaviors of WGS.This study prepares reconstituted WGS with different mica contents by removing natural mica in theWGS,and then mixes it with commercial mica powders.The geotechnical behavior as well as the microstructures of the mixtures are characterized.The addition of mica enables the physical indices of WGS to be specific combinations of coarser gradation and high permeability but high Atterberg limits.However,high mica content in WGS was found to be associated with undesirable mechanical properties,including increased compressibility,disintegration,and swelling potential,as well as poor compactability and low effective frictional angle.Microstructural analysis indicates that the influence of mica on the responses of mixtures originates from the intrinsic nature of mica as well as the particle packing being formed withinWGS.Mica exists in the mixture as stacks of plates that form a spongy structure with high compressibility and swelling potential.Pores among the plates give the soil high water retention and high Atterberg limits.Large pores are also generated by soil particles with bridging packing,which enhances the permeability and water-soil interactions upon immersion.This study provides a microlevel understanding of how mica dominates the behavior of WGS and provides new insights into the effective stabilization and improvement of micaceous soils.

Field testing of shear strength of granite residual soils

The characteristics of residual soils are very different from those of sedimentary soils.Although the strength characteristics of sedimentary soils have been studied extensively,the shear strength characteristics of granitic residual soils(GRS)subjected to the weathering of parent rocks have rarely been investigated.In this study,the shear strength characteristics of GRS in the Taishan area of southeast China(TSGRS)were studied by field and laboratory tests.The field tests consisted of a cone penetration test(CPT),borehole shear test(BST),self-boring pressuremeter test(SBPT),and seismic dilatometer Marchetti test(SDMT).The shortcomings of laboratory testing are obvious,with potential disturbances arising through the sampling,transportation,and preparation of soil samples.Due to the special structure of GRS samples and the ease of disturbance,the results obtained from laboratory tests were generally lower than those obtained from situ tests.The CPT and scanning electron microscopy(SEM)results indicated significant weathering and crustal hardening in the shallow TSGRS.This resulted in significant differences in the strength and strength parameters of shallow soil obtained by the BST.Based on the SDMT and SBPT results,a comprehensive evaluation method of shear strength for TSGRS was proposed.The SBPT was suitable for evaluating the strength of shallow GRS.The material index(ID)and horizontal stress index(KD)values obtained by the SDMT satisfied the empirical relationship proposed by Marchetti based on the ID index,and were therefore considered suitable for the evaluation of the shear strength of deep GRS.

Diatom-induced impact on shear strength characteristics of finegrained soils

Diatomaceous soils,composed of diatom microfossils with biological origins,have geotechnical properties that are fundamentally different from those of conventional non-diatomaceous fine-grained soils.Despite their high fines content,diatomaceous soils typically exhibit remarkably high shear resistance,approaching that of sandy soils.However,the exact role that diatoms play in controlling the mechanical properties of fine-grained soils and the underlying mechanisms remain unclear.In light of this,the shear strength response of diatomaceous soils was systematically investigated using consolidated undrained triaxial compression tests on diatomekaolin mixtures(DKMs)with various diatom contents and overconsolidation ratios.The micro-and nano-scale structures of the soil samples were characterized in detail using scanning electron microscope(SEM)and atomic force microscope(AFM)to interpret the abnormal shear strength parameters of diatomaceous soils.The results indicated that the presence of diatoms could contribute to significantly higher strength,e.g.the friction angle of DKMs was improved by 72.7%to 37and the value of undrained shear strength tripled with diatom content increasing from 20%to 100%.Such significant improvement in soil strength with diatom inclusion could be attribute to the hard siliceous skeleton of diatoms and the interlocking between particles with rough surfaces,which were quantitatively analyzed by the surface roughness parameters with AFM.Furthermore,a conceptual model established based on the macro-mechanical tests and microscopic observations portrays a microstructural evolution of soils with increasing diatoms.The microstructure of soils was gradually transformed from the matrix-type to the skeletal one,resulting in a continual augmentation in shear strength through mutual interactions between diatom microfossils.This paper provides new insights into the multi-scale structural properties of diatoms and significantly advances our understanding of the mechanical behavior of diatomaceous soils.

Dredged marine soil stabilization using magnesia cement augmented with biochar/slag

Dredged marine soils(DMS)have poor engineering properties,which limit their usage in construction projects.This research examines the application of reactive magnesia(rMgO)containing supplementary cementitious materials(SCMs)to stabilize DMS under ambient and carbon dioxide(CO_(2))curing conditions.Several proprietary experimental tests were conducted to investigate the stabilized DMS.Furthermore,the carbonation-induced mineralogical,thermal,and microstructural properties change of the samples were explored.The findings show that the compressive strength of the stabilized DMS fulfilled the 7-d requirement(0.7-2.1 MPa)for pavement and building foundations.Replacing rMgO with SCMs such as biochar or ground granulated blast-furnace slag(GGBS)altered the engineering properties and particle packing of the stabilized soils,thus influencing their performances.Biochar increased the porosity of the samples,facilitating higher CO_(2) uptake and improved ductility,while GGBS decreased porosity and increased the dry density of the samples,resulting in higher strength.The addition of SCMs also enhanced the water retention capacity and modified the pH of the samples.Microstructural analysis revealed that the hydrated magnesium carbonates precipitated in the carbonated samples provided better cementation effects than brucite formed during rMgO hydration.Moreover,incorporating SCMs reduced the overall global warming potential and energy demand of the rMgO-based systems.The biochar mixes demonstrated lower toxicity and energy consumption.Ultimately,the rMgO and biochar blend can serve as an environmentally friendly additive for soft soil stabilization and permanent fixation of significant amounts of CO_(2) in soils through mineral carbonation,potentially reducing environmental pollution while meeting urbanization needs.

Effects of dry-wet cycles on three-dimensional pore structure and permeability characteristics of granite residual soil using X-ray micro computed tomography

Due to seasonal climate alterations,the microstructure and permeability of granite residual soil are easily affected by multiple dry-wet cycles.The X-ray micro computed tomography(micro-CT)acted as a nondestructive tool for characterizing the microstructure of soil samples exposed to a range of damage levels induced by dry-wet cycles.Subsequently,the variations of pore distribution and permeability due to drywet cycling effects were revealed based on three-dimensional(3D)pore distribution analysis and seepage simulations.According to the results,granite residual soils could be separated into four different components,namely,pores,clay,quartz,and hematite,from micro-CT images.The reconstructed 3D pore models dynamically demonstrated the expanding and connecting patterns of pore structures during drywet cycles.The values of porosity and connectivity are positively correlated with the number of dry-wet cycles,which were expressed by exponential and linear functions,respectively.The pore volume probability distribution curves of granite residual soil coincide with the χ^(2)distribution curve,which verifies the effectiveness of the assumption of χ^(2)distribution probability.The pore volume distribution curves suggest that the pores in soils were divided into four types based on their volumes,i.e.micropores,mesopores,macropores,and cracks.From a quantitative and visual perspective,considerable small pores are gradually transformed into cracks with a large volume and a high connectivity.Under the action of dry-wet cycles,the number of seepage flow streamlines which contribute to water permeation in seepage simulation increases distinctly,as well as the permeability and hydraulic conductivity.The calculated hydraulic conductivity is comparable with measured ones with an acceptable error margin in general,verifying the accuracy of seepage simulations based on micro-CT results.

Site observations of weathered granitic soils subjected to cementation and partial drainage using SCPTU

Because of the cementation inherited from the parent rock,weathered granitic soil is usually susceptible to disturbance,which poses considerable challenges for laboratory characterization.The cone penetration test with pore pressure measurements has long been known for its reliability in site investigations and stratigraphic profiling.However,although extensive piezocone test results and experience are available for sedimentary soil,similar advances are yet to be made for weathered granitic soil.Moreover,the experience from sedimentary soil may not be directly applicable to weathered profiles because of the essentially different natures of the two types of geomaterials.This study performs seismic piezocone tests in a weathered granitic profile comprising residual granitic soil,completely weathered granite,and highly weathered granite.Pore pressure is measured at both the cone mid-face and the shoulder,and the effects of penetrometer size and penetration rate are considered.A series of updated soil behavior type charts is proposed to interpret the test results,thereby allowing the effect of weathering to be evaluated.This paper offers an important extension to the sparse data on the in situ responses of weathered materials.

HER2 gene status and the relationship with p21 protein expression in gastric cancer

Objective： We aimed to analysis the HER2 gene status and its relationship with p21 protein expression in gastric carcinoma. Methods： Fluorescence in situ hybridisation （FISH） and immunohistochemistry （IHC） techniques were used to detect HER2 gene status and p53 protein in 59 cases of gastric cancer. Results： FISH detection of HER2 gene amplification rate was 16.9% （10/59）, HER2 gene amplification in 49 cases without copy number gain and gene amplification were a total of 49.2% （29/59）. HER2 protein expression was 42.4% （25/59）, HER2 gene amplification rates in patients with ＋＋＋, ＋＋ HER2 protein expression were 3/3 and 5/8, while in patients with ＋ HER2 protein expression, it was 2/14, there was significant difference （P 0.05）. p21 protein expression rate was 49.2% （29/59）, HER2 gene amplification rates and p21 protein expression had significant difference in tumor invasion depth, lymph node metastasis （P 0.05）; had no statistical significance in histological type, age, gender differences （P 0.05）. Conclusion： HER2 gene amplification rate and gene copy number had positively correlation with p21 protein expression, HER2 gene status and expression of p21 protein combined detection can provide a reference value in gastric cancer metastasis, patient’s condition development and prognosis, it also can guide clinical development of individual treatment.

流数据边缘处理探讨

结合空管信息技术的特点,"胖客户端"是常态,即使用端资源充足,但是网络带宽比较狭窄,没有互联网应用动辄千兆甚至更高的带宽,同时空管信息技术具有近端服务的特点,越是靠近该地区的,需要的数据越大并且数据时延要求越高,因此在空管信息技术领域,流数据的边缘处理技术具有广阔的应用前景。而该系统采用了分布式流转算子的思路,采用流转算子,解决了需要多次流转大量的数据导致带宽资源更加拥堵以及时延更大的问题。

婴儿纤维性错构瘤33例临床病理及分子遗传学分析

目的探讨婴儿纤维性错构瘤(fibrous hamartoma of infancy,FHI)的临床病理学特征、免疫表型、分子遗传学特点。方法收集河南省人民医院病理科2011年10月至2020年12月经手术切除的的33例FHI患者的临床及病理学资料,结合随访资料进行分析,并应用二代测序技术及即时荧光定量聚合酶链反应(q-PCR)技术对其进行分子遗传学研究。结果本组患者发病年龄范围6个月至6岁,平均16.7个月,男患儿21例,女患儿12例,发病部位包括躯干(21例)、四肢(11例)、颈部(1例)。均表现为无痛性孤立性浅表软组织肿块,大小为1.5~9.0 cm(平均3.8 cm)。镜下均由成熟脂肪组织、纤维母细胞/肌纤维母细胞束及原始间叶细胞以不同比例混合组成,14例中见多少不等的巨细胞纤维母细胞瘤样区域。免疫组织化学示梭形细胞和原始间叶成分不同程度表达表皮生长因子受体(EGFR),多数病例中梭形细胞表达CD34和平滑肌肌动蛋白,伴巨细胞纤维母细胞瘤样区域均强表达CD34,脂肪细胞恒定表达S-100蛋白,Ki-67阳性指数1%~5%。6例行二代测序检测均存在体细胞EGFR第20号外显子插入/重复突变,共检出3种不同的突变类型:p.Asn771;is773dupAsnProHis、p.Pro772;is773insProProHis和p.His773;al774insThrHis。应用q-PCR方法对该6例及另外15例FHI进行验证,均显示有EGFR第20号外显子插入/重复突变。结论FHI是一种少见的良性纤维母细胞/肌纤维母细胞性肿瘤,器官样三相性形态是其特征性的组织学特点,体细胞EGFR第20号外显子插入/重复突变是其分子特征。

Effects of mesh loop modes on performance of unstructured finite volume GPU simulations

In unstructured finite volume method,loop on different mesh components such as cells,faces,nodes,etc is used widely for the traversal of data.Mesh loop results in direct or indirect data access that affects data locality significantly.By loop on mesh,many threads accessing the same data lead to data dependence.Both data locality and data dependence play an important part in the performance of GPU simulations.For optimizing a GPU-accelerated unstructured finite volume Computational Fluid Dynamics(CFD)program,the performance of hot spots under different loops on cells,faces,and nodes is evaluated on Nvidia Tesla V100 and K80.Numerical tests under different mesh scales show that the effects of mesh loop modes are different on data locality and data dependence.Specifically,face loop makes the best data locality,so long as access to face data exists in kernels.Cell loop brings the smallest overheads due to non-coalescing data access,when both cell and node data are used in computing without face data.Cell loop owns the best performance in the condition that only indirect access of cell data exists in kernels.Atomic operations reduced the performance of kernels largely in K80,which is not obvious on V100.With the suitable mesh loop mode in all kernels,the overall performance of GPU simulations can be increased by 15%-20%.Finally,the program on a single GPU V100 can achieve maximum 21.7 and average 14.1 speed up compared with 28 MPI tasks on two Intel CPUs Xeon Gold 6132.

CRISPR/Cas13系统敲减HEK293T细胞ku70和lig4基因表达

成簇的规律间隔的短回文重复序列(Clustered regularly interspaced short palindromic repeats,CRISPR)/CRISPR相关蛋白(CRISPR-associated proteins,Cas)系统是目前基因编辑、基因表达研究的热点,其中靶向RNA的CRISPR/Cas13系统的开发为RNA的干扰和编辑提供了新的方向。文中针对HEK293T细胞非同源末端连接(Nonhomologousendjoining,NHEJ)通路修复关键因子Ku70和Lig4的编码序列,设计并合成CRISPR/Cas13a、b系统相应的gRNA,检测其对ku70和lig4基因表达的影响。结果显示,Cas13a对ku70和lig4的RNA敲减效果可以达到50%以上,Cas13b对ku70和lig4的RNA敲减效果分别达到92%和76%;同时Cas13a、b系统能将Ku70和Lig4蛋白水平分别下调至68%和53%。CRISPR/Cas13系统可有效敲减HEK293T细胞RNA和蛋白质表达,为基因功能和调控研究提供一种新的策略。

PIK-75 promotes homology-directed DNA repair

Homo!ogy-directed repair(HDR)is one of two major DNA repair pathways to mend the double-strand breaks(DSBs)formed in the genome(Liang et al.,1998;Pardo et al.,2009).Although less efficient compared with another DNA repair pathway,nonhomologous end joining(NHEJ),HDR is a type of precise repair to restore DNA damage and sustain genomic stability(Pardo et al.,2009;Ceccaldi et al.,2016).By contrast,NHEJ usually introduces mutations into the repaired site,thus probably harming the genomic integrity(Lieber et al.,2003).The error-free property enables HDR to be harnessed to correct a faulty mutation for therapeutic purpose in cells or in the body(Wu et al.,2013).In add让ion,HDR possesses great potential in the generation of genome-edited animals with precise genetic modifications,such as point mutation,DNA replacement,and DNA insertion in a specific genomic site(Wang et al.,2013).However,the low repair frequency mediated by HDR significantly limits让s application for efficient gene correction or establishment of various genetically modified animal models.Currently,multiple site-specific endonucleases have emerged as highly efficient tools to create targeted DSBs and markedly promote subsequent DNA repair either via HDR or NHEJ(Gaj et al.,2013).Nonetheless,the HDR-mediated modifications following the cleavage of engineering nucleases are still inefficient,usually with an efficiency less than 20%in cultured mammalian cells and embryos(Mali et al..2013;Wang et al.,2013;Yang et al.,2013).