In this work, we study the influence of the annealing treatment on the behaviour of titanium dioxide nanotube layers. The heat treatment protocol is actually the key parameter to induce stable oxide layers and needs t...In this work, we study the influence of the annealing treatment on the behaviour of titanium dioxide nanotube layers. The heat treatment protocol is actually the key parameter to induce stable oxide layers and needs to be better understood. Nanotube layers were prepared by electrochemical anodization of Ti foil in 0.4 wt% hydrofluoric acid solution during 20 minutes and then annealed in air atmosphere. In-situ X-ray diffraction analysis, coupled with thermogravimetry, gives us an inside on the oxidation behaviour of titanium dioxide nanotube layers compared to bulk reference samples. Structural studies were performed at 700°C for 12 h in order to follow the time consequences on the oxidation of the material, in sufficient stability conditions. In-situ XRD brought to light that the amorphous oxide layer induced by anodization is responsible for the simultaneous growths of anatase and rutile phase during the first 30 minutes of annealing while the bulk sample oxidation leads to the nucleation of a small amount of anatase TiO<sub>2</sub>. The initial amorphous oxide layer created by anodization is also responsible for the delay in crystallization compared to the bulk sample. Thermogravimetric analysis exhibits parabolic shape of the mass gain for both anodized and bulk sample;this kinetics is caused by the formation of a rutile external protective layer, as depicted by the associated in-situ XRD diffractograms. We recorded that titanium dioxide nanotube layers exhibit a lower mean mass gain than the bulk, because of the presence of an initial amorphous oxide layer on anodized samples. In-situ XRD results also provide accurate information concerning the sub-layers behavior during the annealing treatment for the bulk and nanostructured layer. Anatase crystallites are mainly localized at the interface oxide layer-metal and the rutile is at the external interface. Sample surface topography was characterized using scanning electron microscopy (SEM). As a probe of the photoactivity of the annealed TiO<sub>2</sub> nanotube layers, degradation of an acid orange 7 (AO7) dye solution and 4-chlorophenol under UV irradiation (at 365 nm) were performed. Such titanium dioxide nanotube layers show an efficient photocatalytic activity and the analytical results confirm the degradation mechanism of the 4-chlorophenol reported elsewhere.展开更多
BACKGROUND In their everyday life,clinicians face an overabundance of biological indicators potentially helpful during a disease therapy.In this context,to be able to reliably identify a reduced number of those marker...BACKGROUND In their everyday life,clinicians face an overabundance of biological indicators potentially helpful during a disease therapy.In this context,to be able to reliably identify a reduced number of those markers showing the ability of optimising the classification of treatment outcomes becomes a factor of vital importance to medical prognosis.In this work,we focus our interest in inflammatory bowel disease(IBD),a long-life threaten with a continuous increasing prevalence worldwide.In particular,IBD can be described as a set of autoimmune conditions affecting the gastrointestinal tract whose two main types are Crohn’s disease and ulcerative colitis.AIM To identify the minimal signature of microRNA(miRNA)associated with colorectal cancer(CRC)in patients with one chronic IBD.METHODS We provide a framework of well-established statistical and computational learning methods wisely adapted to reconstructing a CRC network leveraged to stratify these patients.RESULTS Our strategy resulted in an adjusted signature of 5 miRNAs out of approximately 2600 in Crohn’s Disease(resp.8 in Ulcerative Colitis)with a percentage of success in patient classification of 82%(resp.81%).CONCLUSION Importantly,these two signatures optimally balance the proportion between the number of significant miRNAs and their percentage of success in patients’stratification.展开更多
The retinoid receptor-related orphan receptor alpha（RORα） is thought to act as a constitutive activator of transcription by binding to the ROR response element（RORE） of target genes. Several mouse models in which...The retinoid receptor-related orphan receptor alpha（RORα） is thought to act as a constitutive activator of transcription by binding to the ROR response element（RORE） of target genes. Several mouse models in which RORα is defective have revealed the decisive roles of RORα on the development, maturation and neuroprotection of various cerebral regions including the cerebellar and somatosensory systems. We have recently shown that RORα is needed for accurate thalamic sensory system organization and somatosensory cortex development. The phenotype of various RORα deficient mice models（staggerer mutant or mouse lacking RORα in specific somatosensory regions） is, in part, reminiscent of what has been described in mice lacking thyroid hormone triiodothyronine（T3）. As in in vitro studies or in other models, our studies strongly suggest that the T3/RORα-pathway, among others, is in part responsible for the staggerer phenotype. We have indeed identified some genes that were both regulated by T3 and RORα and that are known to be implicated in the cerebellar or somatosensory system development. Moreover, several groups have shown that RORα is at the crossroad of many biological processes and pathologies, including psychiatric and degenerative disorders. In particular, defective RORα-signalling has been demonstrated in humans to be associated with the emergence of autistic-like disorders. We believe that determining the appropriate amount of RORα activity could be crucial in detecting and preventing the emergence of specific brain diseases.展开更多
The classical view of signaling between cells of immune system includes two major routes of intercellular communication:Through the release of extracellular molecules or a direct interaction between membrane bound rec...The classical view of signaling between cells of immune system includes two major routes of intercellular communication:Through the release of extracellular molecules or a direct interaction between membrane bound receptor and its membrane bound ligand,which initiate a cascade of signaling in target cell.However,recent studies indicate that besides these canonical modes of signaling there are also noncanonical routs of intercellular communications through membrane stripping/membrane exchange/trogocytosis,extracellular traps,exosomes and ectososmes/microparticles.In this review we discuss what are the components of noncanonical pathways of signaling and what role they play in immune cells interactions.展开更多
Phase imaging coupled to micro-tomography acquisition has emerged as a powerful tool to investigate specimens in a non-destructive manner. While the intensity data can be acquired and recorded, the phase information o...Phase imaging coupled to micro-tomography acquisition has emerged as a powerful tool to investigate specimens in a non-destructive manner. While the intensity data can be acquired and recorded, the phase information of the signal has to be “retrieved” from the data modulus only. Phase retrieval is an ill-posed non-linear problem and regularization techniques including a priori knowledge are necessary to obtain stable solutions. Several linear phase recovery methods have been proposed and it is expected that some limitations resulting from the linearization of the direct problem will be overcome by taking into account the non-linearity of the phase problem. To achieve this goal, we propose and evaluate a non-linear algorithm for in-line phase micro-tomography based on an iterative Landweber method with an analytic calculation of the Fréchet derivative of the phase-intensity relationship and of its adjoint. The algorithm was applied in the projection space using as initialization the linear mixed solution. The efficacy of the regularization scheme was evaluated on simulated objects with a slowly and a strongly varying phase. Experimental data were also acquired at ESRF using a propagation-based X-ray imaging technique for the given pixel size 0.68 μm. Two regularization scheme were considered: first the initialization was obtained without any prior on the ratio of the real and imaginary parts of the complex refractive index and secondly a constant a priori value was assumed on ?. The tomographic central slices of the refractive index decrement were compared and numerical evaluation was performed. The non-linear method globally decreases the reconstruction errors compared to the linear algorithm and is achieving better reconstruction results if no prior is introduced in the initialization solution. For in-line phase micro-tomography, this non-linear approach is a new and interesting method in biomedical studies where the exact value of the a priori ratio is not known.展开更多
The plant steroid hormones, brassinosteroids （BRs）, and their precursors, phytosterols, play major roles in plant growth, development, and stress tolerance. Here, we review the impressive progress made during recent...The plant steroid hormones, brassinosteroids （BRs）, and their precursors, phytosterols, play major roles in plant growth, development, and stress tolerance. Here, we review the impressive progress made during recent years in elucidating the components of the sterol and BR metabolic and signaling pathways, and in understanding their mecha- nism of action in both model plants and crops, such as Arabidopsis and rice. We also discuss emerging insights into the regulations of these pathways, their interactions with other hormonal pathways and multiple environmental signals, and the putative nature of sterols as signaling molecules.展开更多
Mouse B1 B cells originate in the embryonic liver and are the major B-cell population in the peritoneal and pleural cavities.1–5 By contrast,mouse B2 B cells originate in the bone marrow and are the major B-cell popu...Mouse B1 B cells originate in the embryonic liver and are the major B-cell population in the peritoneal and pleural cavities.1–5 By contrast,mouse B2 B cells originate in the bone marrow and are the major B-cell population in the bone marrow,spleen,and blood.B1 and B2 B cells differ not only in their origin and locations,but also in their antigen specificity,cell surface markers,capacities for class-switch recombination(CSR)and somatic hypermutation(SHM).IgH cis-regulatory regions and,particularly,transcriptional super-enhancers are major locus regulators under both normal and pathological conditions.6,7 Important differences have been found regarding the ability of the IgH 3′regulatory region(3′RR)super-enhancer to control the B1 and B2 B-cell fate.展开更多
The laboratory rat is a valuable mammalian model organism for basic research and drug discovery. Here we demonstrate an efficient methodology by applying transcription activator-like effector nucleases(TALENs) technol...The laboratory rat is a valuable mammalian model organism for basic research and drug discovery. Here we demonstrate an efficient methodology by applying transcription activator-like effector nucleases(TALENs) technology to generate Leptin receptor(Lepr) knockout rats on the Sprague Dawley(SD) genetic background. Through direct injection of in vitro transcribed m RNA of TALEN pairs into SD rat zygotes, somatic mutations were induced in two of three resulting pups. One of the founders carrying bi-allelic mutation exhibited early onset of obesity and infertility. The other founder carried a chimeric mutation which was efficiently transmitted to the progenies. Through phenotyping of the resulting three lines of rats bearing distinct mutations in the Lepr locus, we found that the strains with a frame-shifted or premature stop codon mutation led to obesity and metabolic disorders. However, no obvious defect was observed in a strain with an in-frame 57 bp deletion in the extracellular domain of Lepr. This suggests the deleted amino acids do not significantly affect Lepr structure and function. This is the first report of generating the Lepr mutant obese rat model in SD strain through a reverse genetic approach. This suggests that TALEN is an efficient and powerful gene editing technology for the generation of disease models.展开更多
This article presents a new numerical method for facial reconstruction.The problem is the following:given a dry skull,reconstruct a virtual face that would help in the identification of the subject.The approach combin...This article presents a new numerical method for facial reconstruction.The problem is the following:given a dry skull,reconstruct a virtual face that would help in the identification of the subject.The approach combines classical features as the use of a skulls/faces database and more original aspects:(1)an original shape matching method is used to link the unknown skull to the database templates;(2)the final face is seen as an elastic 3D mask that is deformed and adapted onto the unknown skull.In this method,the skull is considered as a whole surface and not restricted to some anatomical landmarks,allowing a dense description of the skull/face relationship.Also,the approach is fully automated.Various results are presented to show its efficiency.展开更多
Dear Editor,Microscopic techniques allow either a global mobility analysis of proteins with fluorescence recovery after photobleaching （FRAP） or single-protein mobility characterization with single-particle or quant...Dear Editor,Microscopic techniques allow either a global mobility analysis of proteins with fluorescence recovery after photobleaching （FRAP） or single-protein mobility characterization with single-particle or quantum dot tracking. For instance, total internal reflection fluo- rescence microscopy allowed single-particle tracking （SPT） of Arabidopsis plasma membrane （PM） proteins, revealing their heterogeneous distribution, low lateral diffusion, and dynamic properties in response to salt stress （Li et al., 2011）. Studies of SPT based on green fluorescent protein are unfortunately restricted by the density of proteins at the surface, since diffracted emission fluorescence prevents tracking of individual proteins separated by less than 1 μm. The recent emergence of high-density SPT techniques based on temporal emission decorrelation, such as single-particle tracking with photoactivated localization microscopy （sptPALM）, allowed the diffraction limit of classic light microscopy to be broken and reach nanometerlevel spatial resolutions （Manley et al., 2008）. Application of these techniques has rendered possible the characterization of the structural and dynamic heterogeneity of PM proteins with an accuracy of -20-80 nm （Rossier et al., 2012）. Such super-resolved dynamic imaging of membrane proteins has not yet been applied to any plant system. Here, we report the first use in plants of the live-cell sptPALM technique, providing a high-density super-resolved nanoscale map of individual membrane-protein motions.展开更多
文摘In this work, we study the influence of the annealing treatment on the behaviour of titanium dioxide nanotube layers. The heat treatment protocol is actually the key parameter to induce stable oxide layers and needs to be better understood. Nanotube layers were prepared by electrochemical anodization of Ti foil in 0.4 wt% hydrofluoric acid solution during 20 minutes and then annealed in air atmosphere. In-situ X-ray diffraction analysis, coupled with thermogravimetry, gives us an inside on the oxidation behaviour of titanium dioxide nanotube layers compared to bulk reference samples. Structural studies were performed at 700°C for 12 h in order to follow the time consequences on the oxidation of the material, in sufficient stability conditions. In-situ XRD brought to light that the amorphous oxide layer induced by anodization is responsible for the simultaneous growths of anatase and rutile phase during the first 30 minutes of annealing while the bulk sample oxidation leads to the nucleation of a small amount of anatase TiO<sub>2</sub>. The initial amorphous oxide layer created by anodization is also responsible for the delay in crystallization compared to the bulk sample. Thermogravimetric analysis exhibits parabolic shape of the mass gain for both anodized and bulk sample;this kinetics is caused by the formation of a rutile external protective layer, as depicted by the associated in-situ XRD diffractograms. We recorded that titanium dioxide nanotube layers exhibit a lower mean mass gain than the bulk, because of the presence of an initial amorphous oxide layer on anodized samples. In-situ XRD results also provide accurate information concerning the sub-layers behavior during the annealing treatment for the bulk and nanostructured layer. Anatase crystallites are mainly localized at the interface oxide layer-metal and the rutile is at the external interface. Sample surface topography was characterized using scanning electron microscopy (SEM). As a probe of the photoactivity of the annealed TiO<sub>2</sub> nanotube layers, degradation of an acid orange 7 (AO7) dye solution and 4-chlorophenol under UV irradiation (at 365 nm) were performed. Such titanium dioxide nanotube layers show an efficient photocatalytic activity and the analytical results confirm the degradation mechanism of the 4-chlorophenol reported elsewhere.
文摘BACKGROUND In their everyday life,clinicians face an overabundance of biological indicators potentially helpful during a disease therapy.In this context,to be able to reliably identify a reduced number of those markers showing the ability of optimising the classification of treatment outcomes becomes a factor of vital importance to medical prognosis.In this work,we focus our interest in inflammatory bowel disease(IBD),a long-life threaten with a continuous increasing prevalence worldwide.In particular,IBD can be described as a set of autoimmune conditions affecting the gastrointestinal tract whose two main types are Crohn’s disease and ulcerative colitis.AIM To identify the minimal signature of microRNA(miRNA)associated with colorectal cancer(CRC)in patients with one chronic IBD.METHODS We provide a framework of well-established statistical and computational learning methods wisely adapted to reconstructing a CRC network leveraged to stratify these patients.RESULTS Our strategy resulted in an adjusted signature of 5 miRNAs out of approximately 2600 in Crohn’s Disease(resp.8 in Ulcerative Colitis)with a percentage of success in patient classification of 82%(resp.81%).CONCLUSION Importantly,these two signatures optimally balance the proportion between the number of significant miRNAs and their percentage of success in patients’stratification.
基金supported by the Institut National de la Santéet de la Recherche Médicale and the Centre National de la Recherche Scientifique
文摘The retinoid receptor-related orphan receptor alpha（RORα） is thought to act as a constitutive activator of transcription by binding to the ROR response element（RORE） of target genes. Several mouse models in which RORα is defective have revealed the decisive roles of RORα on the development, maturation and neuroprotection of various cerebral regions including the cerebellar and somatosensory systems. We have recently shown that RORα is needed for accurate thalamic sensory system organization and somatosensory cortex development. The phenotype of various RORα deficient mice models（staggerer mutant or mouse lacking RORα in specific somatosensory regions） is, in part, reminiscent of what has been described in mice lacking thyroid hormone triiodothyronine（T3）. As in in vitro studies or in other models, our studies strongly suggest that the T3/RORα-pathway, among others, is in part responsible for the staggerer phenotype. We have indeed identified some genes that were both regulated by T3 and RORα and that are known to be implicated in the cerebellar or somatosensory system development. Moreover, several groups have shown that RORα is at the crossroad of many biological processes and pathologies, including psychiatric and degenerative disorders. In particular, defective RORα-signalling has been demonstrated in humans to be associated with the emergence of autistic-like disorders. We believe that determining the appropriate amount of RORα activity could be crucial in detecting and preventing the emergence of specific brain diseases.
基金Supported by William Stamps Farish FundDonald D.Hammill Foundation
文摘The classical view of signaling between cells of immune system includes two major routes of intercellular communication:Through the release of extracellular molecules or a direct interaction between membrane bound receptor and its membrane bound ligand,which initiate a cascade of signaling in target cell.However,recent studies indicate that besides these canonical modes of signaling there are also noncanonical routs of intercellular communications through membrane stripping/membrane exchange/trogocytosis,extracellular traps,exosomes and ectososmes/microparticles.In this review we discuss what are the components of noncanonical pathways of signaling and what role they play in immune cells interactions.
文摘Phase imaging coupled to micro-tomography acquisition has emerged as a powerful tool to investigate specimens in a non-destructive manner. While the intensity data can be acquired and recorded, the phase information of the signal has to be “retrieved” from the data modulus only. Phase retrieval is an ill-posed non-linear problem and regularization techniques including a priori knowledge are necessary to obtain stable solutions. Several linear phase recovery methods have been proposed and it is expected that some limitations resulting from the linearization of the direct problem will be overcome by taking into account the non-linearity of the phase problem. To achieve this goal, we propose and evaluate a non-linear algorithm for in-line phase micro-tomography based on an iterative Landweber method with an analytic calculation of the Fréchet derivative of the phase-intensity relationship and of its adjoint. The algorithm was applied in the projection space using as initialization the linear mixed solution. The efficacy of the regularization scheme was evaluated on simulated objects with a slowly and a strongly varying phase. Experimental data were also acquired at ESRF using a propagation-based X-ray imaging technique for the given pixel size 0.68 μm. Two regularization scheme were considered: first the initialization was obtained without any prior on the ratio of the real and imaginary parts of the complex refractive index and secondly a constant a priori value was assumed on ?. The tomographic central slices of the refractive index decrement were compared and numerical evaluation was performed. The non-linear method globally decreases the reconstruction errors compared to the linear algorithm and is achieving better reconstruction results if no prior is introduced in the initialization solution. For in-line phase micro-tomography, this non-linear approach is a new and interesting method in biomedical studies where the exact value of the a priori ratio is not known.
文摘The plant steroid hormones, brassinosteroids （BRs）, and their precursors, phytosterols, play major roles in plant growth, development, and stress tolerance. Here, we review the impressive progress made during recent years in elucidating the components of the sterol and BR metabolic and signaling pathways, and in understanding their mecha- nism of action in both model plants and crops, such as Arabidopsis and rice. We also discuss emerging insights into the regulations of these pathways, their interactions with other hormonal pathways and multiple environmental signals, and the putative nature of sterols as signaling molecules.
基金by grants from Ligue Contre le Cancer(Equipe labellisée LIGUE 2018)Agence Nationale de la Recherche(ANR:projet EpiSwitch-3′RR 2016)+3 种基金N.G.was supported by a grant from Association de Spécialisation et d’Orientation Scientifique(Lebanon)the municipality of Khiam(Lebanon)and the SociétéFrançaise d’HématologieH.I.is supported by a fellowship from the University of LimogesF.B.is supported by Fondation Partenariale de l′Universitéde Limoges and ALURAD.
文摘Mouse B1 B cells originate in the embryonic liver and are the major B-cell population in the peritoneal and pleural cavities.1–5 By contrast,mouse B2 B cells originate in the bone marrow and are the major B-cell population in the bone marrow,spleen,and blood.B1 and B2 B cells differ not only in their origin and locations,but also in their antigen specificity,cell surface markers,capacities for class-switch recombination(CSR)and somatic hypermutation(SHM).IgH cis-regulatory regions and,particularly,transcriptional super-enhancers are major locus regulators under both normal and pathological conditions.6,7 Important differences have been found regarding the ability of the IgH 3′regulatory region(3′RR)super-enhancer to control the B1 and B2 B-cell fate.
基金supported by the State Key Development Programs of China (2012CB910400 to Mingyao Liu)the National Natural Science Foundation of China (31371455, 31171318 and 81330049)the Science and Technology Commission of Shanghai Municipality (14140900300)
文摘The laboratory rat is a valuable mammalian model organism for basic research and drug discovery. Here we demonstrate an efficient methodology by applying transcription activator-like effector nucleases(TALENs) technology to generate Leptin receptor(Lepr) knockout rats on the Sprague Dawley(SD) genetic background. Through direct injection of in vitro transcribed m RNA of TALEN pairs into SD rat zygotes, somatic mutations were induced in two of three resulting pups. One of the founders carrying bi-allelic mutation exhibited early onset of obesity and infertility. The other founder carried a chimeric mutation which was efficiently transmitted to the progenies. Through phenotyping of the resulting three lines of rats bearing distinct mutations in the Lepr locus, we found that the strains with a frame-shifted or premature stop codon mutation led to obesity and metabolic disorders. However, no obvious defect was observed in a strain with an in-frame 57 bp deletion in the extracellular domain of Lepr. This suggests the deleted amino acids do not significantly affect Lepr structure and function. This is the first report of generating the Lepr mutant obese rat model in SD strain through a reverse genetic approach. This suggests that TALEN is an efficient and powerful gene editing technology for the generation of disease models.
基金support by Idex Sorbonne Universites under the French funds“Investissements d’Avenir”[grant number ANR-11-IDEX-0004-02].
文摘This article presents a new numerical method for facial reconstruction.The problem is the following:given a dry skull,reconstruct a virtual face that would help in the identification of the subject.The approach combines classical features as the use of a skulls/faces database and more original aspects:(1)an original shape matching method is used to link the unknown skull to the database templates;(2)the final face is seen as an elastic 3D mask that is deformed and adapted onto the unknown skull.In this method,the skull is considered as a whole surface and not restricted to some anatomical landmarks,allowing a dense description of the skull/face relationship.Also,the approach is fully automated.Various results are presented to show its efficiency.
文摘Dear Editor,Microscopic techniques allow either a global mobility analysis of proteins with fluorescence recovery after photobleaching （FRAP） or single-protein mobility characterization with single-particle or quantum dot tracking. For instance, total internal reflection fluo- rescence microscopy allowed single-particle tracking （SPT） of Arabidopsis plasma membrane （PM） proteins, revealing their heterogeneous distribution, low lateral diffusion, and dynamic properties in response to salt stress （Li et al., 2011）. Studies of SPT based on green fluorescent protein are unfortunately restricted by the density of proteins at the surface, since diffracted emission fluorescence prevents tracking of individual proteins separated by less than 1 μm. The recent emergence of high-density SPT techniques based on temporal emission decorrelation, such as single-particle tracking with photoactivated localization microscopy （sptPALM）, allowed the diffraction limit of classic light microscopy to be broken and reach nanometerlevel spatial resolutions （Manley et al., 2008）. Application of these techniques has rendered possible the characterization of the structural and dynamic heterogeneity of PM proteins with an accuracy of -20-80 nm （Rossier et al., 2012）. Such super-resolved dynamic imaging of membrane proteins has not yet been applied to any plant system. Here, we report the first use in plants of the live-cell sptPALM technique, providing a high-density super-resolved nanoscale map of individual membrane-protein motions.
