A continuous and long-term in-situ stress measuring method based on fiber optic. Part I: Theory of inverse differential strain analysis

A method for in-situ stress measurement via fiber optics was proposed. The method utilizes the relationship between rock mass elastic parameters and in-situ stress. The approach offers the advantage of long-term stress measurements with high spatial resolution and frequency, significantly enhancing the ability to measure in-situ stress. The sensing casing, spirally wrapped with fiber optic, is cemented into the formation to establish a formation sensing nerve. Injecting fluid into the casing generates strain disturbance, establishing the relationship between rock mass properties and treatment pressure.Moreover, an optimization algorithm is established to invert the elastic parameters of formation via fiber optic strains. In the first part of this paper series, we established the theoretical basis for the inverse differential strain analysis method for in-situ stress measurement, which was subsequently verified using an analytical model. This paper is the fundamental basis for the inverse differential strain analysis method.

A fractional differential constitutive model for dynamic stress intensity factors of an anti-plane crack in viscoelastic materials

Fractional differential constitutive relationships are introduced to depict the history of dynamic stress inten- sity factors （DSIFs） for a semi-infinite crack in infinite viscoelastic material subjected to anti-plane shear impact load. The basic equations which govern the anti-plane deformation behavior are converted to a fractional wave-like equation. By utilizing Laplace and Fourier integral transforms, the fractional wave-like equation is cast into an ordinary differential equation （ODE）. The unknown function in the solution of ODE is obtained by applying Fourier transform directly to the boundary conditions of fractional wave-like equation in Laplace domain instead of solving dual integral equations. Analytical solutions of DSIFs in Laplace domain are derived by Wiener-Hopf technique and the numerical solutions of DSIFs in time domain are obtained by Talbot algorithm. The effects of four parameters α, β, b1, b2 of the fractional dif- ferential constitutive model on DSIFs are discussed. The numerical results show that the present fractional differential constitutive model can well describe the behavior of DSIFs of anti-plane fracture in viscoelastic materials, and the model is also compatible with solutions of DSIFs of anti-plane fracture in elastic materials.

Size-dependent effect on biaxial and shear nonlinear buckling analysis of nonlocal isotropic and orthotropic micro-plate based on surface stress and modified couple stress theories using differential quadrature method

The size-dependent effect on the biaxial and shear nonlinear buckling analysis of an isotropic and orthotropic micro-plate based on the surface stress, the modified couple stress theory （MCST）, and the nonlocal elasticity theories using the differential quadrature method （DQM） is presented. Main advantages of the MCST over the classical theory （CT） are the inclusion of the asymmetric couple stress tensor and the consideration of only one material length scale parameter. Based on the nonlinear von Karman assumption, the governing equations of equilibrium for the micro-classical plate consid- ering midplane displacements are derived based on the minimum principle of potential energy. Using the DQM, the biaxial and shear critical buckling loads of the micro-plate for various boundary conditions are obtained. Accuracy of the obtained results is validated by comparing the solutions with those reported in the literature. A parametric study is conducted to show the effects of the aspect ratio, the side-to-thickness ratio, Eringen＇s nonlocal parameter, the material length scale parameter, Young＇s modulus of the surface layer, the surface residual stress, the polymer matrix coefficients, and various boundary conditions on the dimensionless uniaxial, biaxial, and shear critical buckling loads. The results indicate that the critical buckling loads are strongly sensitive to Eringen＇s nonlocal parameter, the material length scale parameter, and the surface residual stress effects, while the effect of Young＇s modulus of the surface layer on the critical buckling load is negligible. Also, considering the size dependent effect causes the increase in the stiffness of the orthotropic micro-plate. The results show that the critical biaxial buckling load increases with an increase in G12/E2 and vice versa for E1/E2. It is shown that the nonlinear biaxial buckling ratio decreases as the aspect ratio increases and vice versa for the buckling amplitude. Because of the most lightweight micro-composite materials with high strength/weight and stiffness/weight ratios, it is anticipated that the results of the present work are useful in experimental characterization of the mechanical properties of micro-composite plates in the aircraft industry and other engineering applications.

Differential Expression of miRNAs in Rice under High Temperature Stress

The growth and development of rice are closely related with temperature. In order to clarify the mechanism of high temperature resistance in riee, in this study, using high temperature-resistant Indian rice cultivar N22 as the experimental material, Osa-rniR159c, Osa-miR159d, Osa-miR159f, Osa-miR164d, Osa- rrdR529b and Osa-miR166h-3p obtained by high-throughput sequencing as target genes, the expression patterns of these genes in young panicles of rice under high temperature stress were analyzed by RNA-tailing and primer-extension RT-PCR, which provided theoretical basis for breeding high temperature-resistant rice eultivars.

AHermitian C^(2) Differential Reproducing Kernel Interpolation Meshless Method for the 3D Microstructure-Dependent Static Flexural Analysis of Simply Supported and Functionally Graded Microplates

This work develops a Hermitian C^(2) differential reproducing kernel interpolation meshless(DRKIM)method within the consistent couple stress theory(CCST)framework to study the three-dimensional(3D)microstructuredependent static flexural behavior of a functionally graded(FG)microplate subjected to mechanical loads and placed under full simple supports.In the formulation,we select the transverse stress and displacement components and their first-and second-order derivatives as primary variables.Then,we set up the differential reproducing conditions(DRCs)to obtain the shape functions of the Hermitian C^(2) differential reproducing kernel(DRK)interpolant’s derivatives without using direct differentiation.The interpolant’s shape function is combined with a primitive function that possesses Kronecker delta properties and an enrichment function that constituents DRCs.As a result,the primary variables and their first-and second-order derivatives satisfy the nodal interpolation properties.Subsequently,incorporating ourHermitianC^(2)DRKinterpolant intothe strong formof the3DCCST,we develop a DRKIM method to analyze the FG microplate’s 3D microstructure-dependent static flexural behavior.The Hermitian C^(2) DRKIM method is confirmed to be accurate and fast in its convergence rate by comparing the solutions it produces with the relevant 3D solutions available in the literature.Finally,the impact of essential factors on the transverse stresses,in-plane stresses,displacements,and couple stresses that are induced in the loaded microplate is examined.These factors include the length-to-thickness ratio,the material length-scale parameter,and the inhomogeneity index,which appear to be significant.

Differentially Expressed Proteins in Rat Hippocampus after Chronic Immobilization Stress and Intervention Using Xiao Yao San Decoction

Objective To identify differentially expressed proteins in the hippocampus of rats after chronic immobilization stress(CIS)using a proteomics approach,and to study the effect of the Xiao Yao San(XYS)decoction on differentially expressed proteins.Methods Twenty-four Sprague Dawley rats were randomly assigned to one of four groups of equal body weight:control(non-stress),7-day stress,21-day stress and21-day stress+XYS treatment groups.Two-dimensional gel electrophoresis(2-DE)was used to detect differences in protein expression in rat hippocampus.One differentially expressed protein was measured and verified by western blotting.Results Seventeen proteins showed differential expression.Among these,eight could be identified:glial fibrillary acidic protein-2(GFAP-2),tubulin alpha-1c,cytoplasmic muscle actin2,14-3-3protein,β-2a tubulin,phosphatidylethanolamine binding protein,synucleinαsyn3,and a low molecular weight(18kD)protein.Six of these proteins exhibited increased expression,one showed decreased expression,and the other protein,which comprised five subtypes,were either increased or decreased.These proteins are known to be involved in immunity,signal transduction,cell cycle control,apoptosis,regulation of enzyme activity,cytoskeleton structure,and synaptic plasticity.GFAP-2was further analyzed,and its differential expression confirmed by western blotting.Conclusion Some proteins are differentially expressed in the hippocampus of rats under chronic stress.The biological functions of these differentially expressed proteins are varied.Finally,the XYS decoction can significantly up-or down-regulate these protein expression levels.

Response mechanism for widened pavement structure subjected to ground differential settlement

By the use of a large-scale ground differential settlement simulator, a full-size model test is performed to study the strain response and the deformation behavior of both the wearing course of asphalt cement and the base course of cement-stabilized gravel. Moreover, with the differential settlement at the bottom of the pavement structure as the constraint condition, a plane finite element model is established, which is used to study the stress variation of different pavement layers in response to the differential settlement of varying magnitudes. It shows that, under the effects of the ground differential settlement, the wearing course is subjected to the tensile stress while the base course to the compressive stress and the maximum additional tensile stress and compressive stress occur in the area of 1 m from the splicing joint between the new and the old subgrade. Plastic deformation develops in both layers when the ground differential settlement reaches 14 cm. When the differential settlement at the bottom of the pavement goes up to 1 cm, the maximum additional stress in the surface of the base course will reach 0. 28 MPa, which surpasses 0.276 MPa that is specified in the current specifications as the maximum splitting tensile strength for cement-stabilized base material.

Identification of Differentially Expressed Genes Induced by Ammonium Nitrogen in Rice Using mRNA Differential Display

RNAs isolated from ammonium- and nitrate-treated rice leaves were used to screen differentially expressed genes through mRNA differential display. A total of 72 bands appeared significant differences and some of them were further confirmed by reverse Northern and Northern blot. The results showed that two genes, A-02 （Oryza sativa drought stress related mRNA） and A-03 （Zea mays partial mRNA for TFIIB-related protein） were highly up-regulated in the ammonium-fed rice leaves. The enzyme assays showed that the activities of the two anti-oxidative enzymes, catalase and peroxidase, and the content of a non-enzymic antioxidant, glutathione, were significantly higher in the ammonium-fed rice leaves than those in the nitrate-fed ones, indicating that the ammonium nutrition might be beneficial for rice plants to improve the stress resistance during growth and development.

Effects of shear stress on differentiation of stem cells into endothelial cells

Stem cell transplantation is an appealing potential therapy for vascular diseases and an indispensable key step in vascular tissue engineering.Substantial effort has been made to differentiate stem cells toward vascular cell phenotypes,including endothelial cells(ECs)and smooth muscle cells.The microenvironment of vascular cells not only contains biochemical factors that influence differentiation but also exerts hemodynamic forces,such as shear stress and cyclic strain.More recently,studies have shown that shear stress can influence the differentiation of stem cells toward ECs.A deep understanding of the responses and underlying mechanisms involved in this process is essential for clinical translation.This review highlights current data supporting the role of shear stress in stem cell differentiation into ECs.Potential mechanisms and signaling cascades for transducing shear stress into a biological signal are proposed.Further study of stem cell responses to shear stress will be necessary to apply stem cells for pharmacological applications and cardiovascular implants in the realm of regenerative medicine.

METHOD OF EQUILIBRIUM DIFFERENTIAL EQUATION FOR ANALYSIS OF STRENGTH OF LARGE DEFLECTION DRILL STRING

To counter the strength problem of drill string in well of large curvature and small diameter, well axis was taken as datum mis. Based on description of deflection of well an's and on analysis of three dimensional forces of a small section of drill string, equilibrium differential equations of large deflection drill string were established. The internal forces were found by Longe-Kutta method. The stresses were found by using them and the strength prerequisite was established. Stresses of drill string in lateral horizontal well H767 were computed. The results are in agreement with those of finite element model and soft-rope rigidified model. But the method is simpler for computation than finite element model and is more perfect than soft-rope rigidified model. Curvature of the well is too large and there is stress concentration so that the fraction accident of drill string occurs.

RNA-binding proteins related to stress response and differentiation in protozoa

RNA-binding proteins(RBPs) are key regulators of gene expression. There are several distinct families of RBPs and they are involved in the cellular response to environmental changes, cell differentiation and cell death. The RBPs can differentially combine with RNA molecules and form ribonucleoprotein(RNP) complexes, defining the function and fate of RNA molecules in the cell. RBPs display diverse domains that allow them to be categorized into distinct families. They play important roles in the cellular response to physiological stress, in cell differentiation, and, it is believed, in the cellular localization of certain mRNAs. In several protozoa, a physiological stress(nutritional, temperature or pH) triggers differentiation to a distinct developmental stage. Most of the RBPs characterized in protozoa arise from trypanosomatids. In these protozoa gene expression regulation is mostly post-transcriptional, which suggests that some RBPs might display regulatory functions distinct from those described for other eukaryotes. mRNA stability can be altered as a response to stress. Transcripts are sequestered to RNA granules that ultimately modulate their availability to the translation machinery, storage or degradation, depending on the associated proteins. These aggregates of mRNPs containing mRNAs that are not being translated colocalize in cytoplasmic foci, and their numbers and size vary according to cell conditions such as oxidative stress, nutritional status and treatment with drugs that inhibit translation.

Research Progress on the Role of Endoplasmic Reticulum Stress in Osteogenic Differentiation

The endoplasmic reticulum(ER)is the main site for regulating protein synthesis and processing.Endoplasmic reticulum stress plays a role in regulating the osteogenic differentiation of stem cells and general osteoblasts.Bone marrow stromal cells(BMSCs,also known as bone marrow mesenchymal stem cells)are a group of progenitor cells that contain a small number of bone stem cells(SSCs)that rebuild cartilage,bone,stroma,and fat cells that support hematopoiesis and bone marrow.Therefore,due to their self-renewal and differentiation capabilities,they have become an important resource for researching regenerative medicine and tissue engineering treatment strategies.Exposure of osteoblasts to physical and biochemical stimuli facilitates rapid activation of early tissue repair processes in organisms.Therefore,the rational regulation of the induction conditions of osteoblasts has become a hot research topic.This article reviews the recent advances in the role of endoplasmic reticulum stress in the process of osteoblast differentiation.

A variational differential quadrature solution to finite deformation problems of hyperelastic shell-type structures:a two-point formulation in Cartesian coordinates

A new numerical approach is presented to compute the large deformations of shell-type structures made of the Saint Venant-Kirchhoff and Neo-Hookean materials based on the seven-parameter shell theory.A work conjugate pair of the first Piola Kirchhoff stress tensor and deformation gradient tensor is considered for the stress and strain measures in the paper.Through introducing the displacement vector,the deformation gradient,and the stress tensor in the Cartesian coordinate system and by means of the chain rule for taking derivative of tensors,the difficulties in using the curvilinear coordinate system are bypassed.The variational differential quadrature(VDQ)method as a pointwise numerical method is also used to discretize the weak form of the governing equations.Being locking-free,the simple implementation,computational efficiency,and fast convergence rate are the main features of the proposed numerical approach.Some well-known benchmark problems are solved to assess the approach.The results indicate that it is capable of addressing the large deformation problems of elastic and hyperelastic shell-type structures efficiently.

骨关节炎的氧化应激相关基因和免疫浸润分析

背景:目前对于骨关节炎的发病机制尚不清楚,缺乏有效控制疾病的手段,且研究多集中在免疫领域,对氧化应激领域研究较少。目的:探索氧化应激与免疫浸润在骨关节炎中的作用,并预测相关miRNA和治疗药物。方法:从GEO数据库中获取GSE55235数据集(10例骨关节炎样本和10例健康对照样本)和GSE55457数据集(10例骨关节炎样本和10例健康对照样本)进行合并,获取差异表达基因,并结合氧化应激基因得到差异表达氧化应激基因。对差异表达氧化应激基因进行KEGG、GO富集分析,并使用GSEA富集分析评价骨关节炎通路和生物过程。使用STRING在线平台和Cytoscape软件建立了蛋白质相互作用网络,运行Degree算法得到关键基因,从GEO数据库中获取GSE1919作为验证数据集,对关键基因进行差异分析及受试者工作特征曲线分析,得到核心基因。此外,用CIBERSORT对免疫浸润进行评估,并探索核心基因与免疫细胞的相关性,使用TargetScan对核心基因进行miRNA预测及使用DSigDB数据库对靶点药物进行预测。结果与结论:①确定了65个差异表达氧化应激基因和5个核心基因(IL1B、CXCL8、MYC、NFKBIA、JUN);②富集分析结果显示,差异表达氧化应激基因的主要聚焦点包括氧化应激、白细胞介素17、破骨细胞分化、流体剪切应力以及动脉粥样硬化等通路;③5个核心基因的受试者工作特征曲线下面积均>0.85,说明对诊断骨关节具有良好的特异性和敏感性,且与免疫细胞密切关联;④miRNA的预测结果是hsa-miR-3937,治疗小分子药物包括二甲双胍、离子霉素和塞来昔布等。结果表明:骨关节炎中存在氧化应激与免疫浸润,且免疫浸润参与激活氧化应激。核心基因及预测的miRNA可作为诊断骨关节炎的新型标志物,预测的小分子药物可治疗骨关节炎。

女贞子活性成分防治骨质疏松症的分子机制

背景:目前,中医药已被证实在抗骨质疏松方面具有显著作用,女贞子活性成分的抗骨质疏松有效性及作用机制逐渐得到学者们的关注。目的:分析总结女贞子活性成分在体内外发挥抗骨质疏松方面的研究进展。方法:检索中国知网及PubMed数据库收录的相关文献,中文检索词为“骨质疏松症,骨髓间充质干细胞,成骨细胞,破骨细胞,女贞子,信号通路”;英文检索词为“Osteoporosis,Bone marrow mesenchymal stem cells,Osteoblast,Osteoclast,Ligustri Lucidi Fructus,Signal path”,并根据研究需要确立相应的标准,对所得文献进行筛选,最终纳入82篇文献进行综述。结果与结论:女贞子活性成分在体内外发挥抗骨质疏松作用主要涉及以下几种重要成分:①红景天苷通过抑制骨硬化蛋白(SOST)和Dickkopf相关蛋白1(Dkk1)的表达,激活了Wnt/β-catenin信号通路,该激活过程增强了去卵巢大鼠和原代成骨细胞中磷酸化低密度脂蛋白受体相关蛋白6(p-LRP6)的表达,同时降低了糖原合酶激酶3β的表达。进一步地,红景天苷促进了细胞核内β-catenin、特异性转录因子2(Runx2)和骨髓细胞瘤病毒癌基因(c-Myc)的表达,从而促进了成骨细胞的骨形成能力。红景天苷可直接作用于成骨细胞,促进骨形成,为骨质疏松症的治疗提供了新的策略。②橄榄苦苷显著提高了SD大鼠的骨密度,并通过降低终末白细胞介素6和碱性磷酸酶浓度来调节骨代谢。体外实验表明,橄榄苦苷促进了成骨细胞的增殖,并上调了骨保护素蛋白和mRNA的表达,同时抑制了核转录因子κB受体活化因子配体(receptor activator of nuclear factor-κB ligand,RANKL)蛋白和mRNA的表达。这一作用机制与调节骨保护素/RANKL系统的平衡密切相关,展现出能提高骨密度,又能通过调节骨代谢相关因子来维护骨骼健康的优势,但对Ca2+浓度无显著影响,可能限制了其在某些特定骨质疏松类型中的应用。③松果菊苷通过降低磷脂酰肌醇3-激酶(phosphatidylinositol 3 kinase,PI3K)的表达、减少蛋白激酶B(protein kinase B,Akt)的磷酸化程度和破骨特殊标记蛋白(c-Fos)的表达,有效抑制了破骨细胞中PI3K/Akt/c-Fos通路的激活。这一抑制作用降低了破骨细胞的增殖和成熟能力,从而有助于减少骨吸收,其优势能直接针对破骨细胞进行干预,为骨质疏松症的治疗提供了新的靶点,但是目前对破骨细胞的具体调控机制尚需深入研究,且其长期效果和安全性需进一步评估。④女贞子活性成分在骨质疏松方面展现出良好的治疗效果,但其作用机制复杂,涉及多个基因、蛋白和信号通路的相互作用,未来需开展大规模的临床试验以验证其有效性和安全性,同时需要进一步探索女贞子活性成分与其他药物的联合应用策略,以期获得更好的治疗效果。

非静水压作用下石膏电学性质的理论研究

地球内部广泛存在着差应力,这些外在因素的存在影响着矿物的性质,而矿物的电学性质与结构相变息息相关.为了更加了解地球内部结构与动力学过程,采用第一性原理方法,在等效平衡压0~10 GPa范围内计算地球内部浅层矿物石膏在静水压和非静水压条件下的电学性质.计算结果表明:静水压和非静水压条件下无水石膏的密度和带隙变化基本一致,但二水石膏的密度和带隙在非静水压为6 GPa附近发生突变,这可能是由于非静水压环境使晶体结构更容易发生畸变,更有利于水分子氢键网络的重新排列和CaSO_(4)层间结构的塌缩,因此非静水压下可能更加有利于二水石膏在高温高压下的脱水反应.这对理解地幔中矿物的脱水和储水产生重大的影响,为理解地幔中矿物的脱氢和储水提供理论依据.

Isolation, Expression Characteristics and Chromosomal Locations of Three cDNA Fragments Under Salt Stress in Rice

cDNA libraries were constructed from the leaves of a rice (Oryza sativa L.) salt tolerancevariety Tesan抋i 2 growing in solutions with 150 mmol/L NaCl for 3 h or without salt stress. Three salt-responsive cDNA clones, Ts1, Ts2 and Ts3 were isolated by differential screening. Northern blottinganalysis showed that the transcription levels of Ts1 and Ts2 increased within 3 h salt stress and kept onincreasing within 24 h, while the transcription level of Ts3 reached its peak within 3 h. Sequence analysisindicated that there were no homologies between the three cDNA clones and any known gene. The threecDNA clones were mapped using a doubled haploid (DH) population derived from an indica variety ZYQ8,which was a salt tolerance parent of Tesan抋i 2, with a japonica variety JX17. Ts1, Ts2 and Ts3 werelocated on chromosomes 1, 3 and 7, respectively. It was noted that Ts1, Ts2, and Ts3 were in or near theregions of major or minor salt tolerance quantitative trait loci (QTLs), which were mapped in the same DHpopulation in a parallel study.

Biotic and abiotic stress-responsive genes are stimulated to resist drought stress in purple wheat

Triticum aestivum L. cv. Guizi 1(GZ1) is a drought-tolerant local purple wheat cultivar. It is not clear how purple wheat resists drought stress, but it could be related to anthocyanin biosynthesis. In this study, transcriptome data from droughttreated samples and controls were compared. Drought slightly reduced the anthocyanin, protein and starch contents of GZ1 grains and significantly reduced the grain weight. Under drought stress, 16 682 transcripts were reduced, 27 766 differentially expressed genes(DEGs) were identified, and 379 DEGs, including DREBs, were related to defense response. The defense-response genes included response to water deprivation, reactive oxygen, bacteria, fungi, etc. Most of the structural and regulatory genes in anthocyanin biosynthesis were downregulated, with only Ta DFR, Ta OMT, Ta5,3GT, and Ta MYB-4 B1 being upregulated. Ta CHS, Ta F3H, TaCHI, Ta4CL, and TaF3’H are involved in responses to UV, hormones, and stimulus. Ta CHS-2D1, Ta DFR-2D2, Ta DFR-7D, TaOMT-5A, Ta5,3 GT-1B1, Ta5,3GT-3A, and Ta5,3GT-7B1 connect anthocyanin biosynthesis with other pathways, and their interacting proteins are involved in primary metabolism, genetic regulation, growth and development, and defense responses. There is further speculation about the defense-responsive network in purple wheat. The results indicated that biotic and abiotic stress-responsive genes were stimulated to resist drought stress in purple wheat GZ1, and anthocyanin biosynthesis also participated in the drought defense response through several structural genes.

Surface stress effect on the vibration and instability of nanoscale pipes conveying fluid based on a size-dependent Timoshenko beam model

Presented in this paper is a precise investigation of the effect of surface stress on the vibration characteristics and instability of fluid-conveying nanoscale pipes.To this end,the nanoscale pipe is modeled as a Timoshenko nanobeam.The equations of motion of the nanoscale pipe are obtained based on Hamilton＇s principle and the Gurtin-Murdoch continuum elasticity incorporating the surface stress effect.Afterwards,the generalized differential quadrature method is employed to discretize the governing equations and associated boundary conditions.To what extent important parameters such as the thickness,material and surface stress modulus,residual surface stress,surface density,and boundary conditions influence the natural frequency of nanoscale pipes and the critical velocity of fluid is discussed.

Regulation of mitochondrial function and endoplasmic reticulum stress by nitric oxide in pluripotent stem cells

Mitochondrial dysfunction and endoplasmic reticulum stress(ERS) are global processes that are interrelated and regulated by several stress factors. Nitric oxide(NO) is a multifunctional biomolecule with many varieties of physiological and pathological functions, such as the regulation of cytochrome c inhibition and activation of the immune response, ERS and DNA damage; these actions are dose-dependent. It has been reported that in embryonic stem cells, NO has a dual role, controlling differentiation, survival and pluripotency, but the molecular mechanisms by which it modulates these functions are not yet known. Low levels of NO maintain pluripotency and induce mitochondrial biogenesis. It is well established that NO disrupts the mitochondrial respiratory chain and causes changes in mitochondrial Ca^(2+) flux that induce ERS. Thus, at high concentrations, NO becomes a potential differentiation agent due to the relationship between ERS and the unfolded protein response in many differentiated cell lines. Nevertheless, many studies have demonstratedthe need for physiological levels of NO for a proper ERS response. In this review, we stress the importance of the relationships between NO levels, ERS and mitochondrial dysfunction that control stem cell fate as a new approach to possible cell therapy strategies.