The organization of the higher order structure of chromatin in chicken erythrocytes has been examined withtapping-mode scanning force microscopy under conditionsclose to their native environment. Reproducible highreso...The organization of the higher order structure of chromatin in chicken erythrocytes has been examined withtapping-mode scanning force microscopy under conditionsclose to their native environment. Reproducible highresolution AFM images of chromatin compaction at several levels can be demonstrated. An extended beads-on-astring (width of ～ 15-20nm, height of ～ 2-3nm for eachindividual nucleosome) can be consistently observed. Furthermore, superbeads (width of ～ 40nm, height of ～ 7nm)are demonstrated. Visualization of the solenoid conformation at the level of 30nm chromatin fiber is attained eitherby using AFM or by using electron microscopy. In addition, tightly coiled chromatin fibers (～ 50-60nm and ～90-110nm) can be revealed. Our data suggest that the chromatin in the interphase nucleus of chicken erythrocyte represents a high-order conformation and AFM provides useful high-resolution structural information concerning thefolding pattern of interphase chromatin fibers.展开更多
The mechanisms for rock bursts occurrences in fold zones are complex, and the redistribution of in-situ stresses is closely related to the complexity of the structures. Analysis of the geomorphology of fold structures...The mechanisms for rock bursts occurrences in fold zones are complex, and the redistribution of in-situ stresses is closely related to the complexity of the structures. Analysis of the geomorphology of fold structures and changes of coal thickness can help identify zones prone to rock bursts to improve safety and productivity in coal mines. This study investigated the distribution characteristics of fold structures in coal seams in fold zones in four mines in northwest China. Geometrical characteristics of fold structures in coal seams and changes of coal thickness were analysed, based on comprehensive evaluation indexes,such as the length–width ratio of folds, interlimb angle, ratio P1 of projected width of fold limbs to that of the hinge zone, curvature ratio P2, the maximum curvature and amplitude. The statistical analysis of the four coal mines shows that the length–width ratio of folds changed from 0.78 to 2.03 and the maximum curvature of cross sections of folds was less than 0.04. The curvature ratio of cross section of a fold in the structure was no more than 1.4 and the interlimb angles of cross sections of 89% of folds were larger than 150°. Gentle fold structures were dominant and the specific geological morphologies were domes or basins. The isopleth of coal thickness above the coal mines showed a fluctuation trend similar to the contour line of the floor of coal seams. The coal thickness in an anticline area was smaller than that in the neighboring syncline area. Therefore, the overall variation of coal thickness in the mining areas was likely to have a relation with the direction of the regional principal stress.展开更多
Flasher origami pattern has been widely utilized to improve the stowage efficiency of deployable structures.Nevertheless,flasher origami cannot be folded fully flat,and they still have great potential for optimization...Flasher origami pattern has been widely utilized to improve the stowage efficiency of deployable structures.Nevertheless,flasher origami cannot be folded fully flat,and they still have great potential for optimization in terms of storage volume and folding creases.In this paper,a flat foldable equiangular spiral folding pattern inspired by the sunflower disk is introduced.Then,a parametric design method for this equiangular spiral crease diagram is introduced in detail.Subsequently,a kinematic model of the equiangular spiral folding pattern is established based on the kinematic equivalence between rigid origami and spherical linkages.A simulation of the developed model demonstrates that the equiangular spiral folding pattern can be folded flat.Using the folded ratio as an evaluation index,the calculated results and experiments show that the equiangular spiral crease pattern can yield fewer creases and improve stowage efficiency in comparison to flasher origami pattern.Equiangular spiral folding pattern can save a considerable amount of space and provide a new approach to spatially deployable structures.展开更多
The chromatin folding patterns in air and liquid were studied by atomicforce microscopy (AFM). A gentle water-air interface method was adopted to spreadchromatin from interphase nucleus of chicken erythrocyte. The chr...The chromatin folding patterns in air and liquid were studied by atomicforce microscopy (AFM). A gentle water-air interface method was adopted to spreadchromatin from interphase nucleus of chicken erythrocyte. The chromatin was ah-sorbed on APS-Inica surfaCe and studied with AFM. Beads-on-a-string were observedand many higher-order structures such as superbeads with dimensions 40-60urn indiameter and 4-7 urn in height were found to string together to make chromatin fibers.When sample spreading and absorbing time were shortened, higher-order chromatinfibers with 60-120 urn in width were observed in air as well as under water environment. These chromatin structures may reflect chromatin folding patterns in the livingcells.展开更多
The current geometric and thermodynamic approaches in protein folding studies do not provide a definite solution to understanding mechanisms of folding of biological proteins. A major problem is that the protein is fi...The current geometric and thermodynamic approaches in protein folding studies do not provide a definite solution to understanding mechanisms of folding of biological proteins. A major problem is that the protein is first synthesized as a linear molecule that subsequently must reach its native configuration in an extremely short time. Hydrophobicity-hydrophilicity models and random search mechanism cannot explain folding to the 3-D functional form in less than 1 second, as it occurs in the intact cell. We propose an integral approach, based on the embedding of proteins in the whole cellular context under the postulate: a life protein is never alone. In this concept the protein molecule is influenced by various long and short distance force fields of nature such as coherent electromagnetic waves and zero-point energy. In particular, the role of solitons is reviewed in relation to a novel GM-scale biophysical principle, revealed by us. This recent finding of a set of discrete EM frequency bands, that either promote or endanger life conditions, could be a key in further studies directed at the morphogenetic aspects of protein folding in a biological evolutionary context. In addition, an alternative hypothesis is presented in which each individual cell may store integral 3-D information holographically at the virtual border of a 4-D hypersphere that surrounds each living cell, providing a field receptive memory structure that is instrumental in guiding the folding process towards coherently oscillating protein networks that are crucial for cell survival.展开更多
Background: Microcirculation is affected in diabetes mellitus and Microvascular abnormalities cause persistent diabetic complications. The aim of this study was nailfold capillaroscopic assessment to describe the path...Background: Microcirculation is affected in diabetes mellitus and Microvascular abnormalities cause persistent diabetic complications. The aim of this study was nailfold capillaroscopic assessment to describe the pathological changes (morphological and structural) in capillary of a large series of patients with type 1 and 2 diabetes. Methods: A cross-sectional study was carried out in a Nailfold Capillaroscopy Center (Tehran-Iran) between 2011 and 2014. The study included 235 types 1, 2 diabetic patients. All patients underwent 10 nailfolds capillaroscopy examinations. Microvascular architecture, disturbances capillary distribution, capillary morphology, capillary density, efferent/afferent limb ratio, subpapillary venular plexus, and morphological abnormalities were evaluated. Conclusions were stated as normalor scleroderma pattern. Results of patients’ capillaroscopic images were recorded and analyzed quantitatively and qualitatively. P value < 0.05 was considered as statistical significance. Results: of all participants with mean age 59.91 ± 12.39, 183 cases (77.9%) were female and 52 (22.1%) were male. Tortuosity of capillaries was more often observed in our subjects (235 cases) followed by angiogenesis (171 cases). Normal and early scleroderma patterns were observed in 195 (83.0%) and 40 cases (17.0%). Based on P values, altered micro vascular architecture, capillary distribution and capillary morphology were more frequent in patients with scleroderma pattern in comparison to patients with normal pattern (P value < 0.05). Morphological abnormalities except from neo formation capillary and mega capillary were also significantly more common in patients with scleroderma pattern than patients in counterpart group (P value < 0.05). Conclusion: Nailfold capillaroscopy as a non-invasive, diagnostic and prognostic method may potentially affect on diabetes outcome and control.展开更多
This paper presents the design and the experimental characterization of a new multi-band antenna consisting of three folded monopoles dedicated to mobile communication systems. The originality of this paper is to get ...This paper presents the design and the experimental characterization of a new multi-band antenna consisting of three folded monopoles dedicated to mobile communication systems. The originality of this paper is to get the PMR (Professional or Private Mobile Radio) band with the GSM (Global System for Mobile Communications), DCS (Digital Cellular System) and UMTS (Universal Mobile Telecommunications System) bands. The main lobe of the antenna radiates in the zenith direction with a linear polarization over all bands. It is interesting to design the proposed antenna in order to obtain better performances in terms of directive radiation pattern (especially in the PMR band) in comparison with the already existing antenna systems in the wireless market for similar purposes. The prototype was studied with the software CST-MWS (Micro wave studio 2012). The antenna has been designed and successfully measured.展开更多
We have measured the angular distributions for 12C ion beam elastically scattered from 12C target of thickness 17.4 μg/cm2 at energies 15, 18 and 21 MeV which is close to the Coulomb barrier energy for 12C + 12C nucl...We have measured the angular distributions for 12C ion beam elastically scattered from 12C target of thickness 17.4 μg/cm2 at energies 15, 18 and 21 MeV which is close to the Coulomb barrier energy for 12C + 12C nuclear system. The elastic scattering of 12C beam on 12C was analysed also at different energies (139.5, 158.8, 180, 240, 288.6, 300, 360 and 420 MeV) from literature in order to obtain the global optical potential parameters, which could fairly reproduce the experimental data. The experimental results were analysed within the framework of both the optical model and the double folding potential obtained with different density-dependent NN interactions which give the corresponding values of the nuclear incompressibility K in the Hartree-Fock calculation of nuclear matter. The agreement between the experimental results and the theoretical predictions in the whole angular range is fairly good.展开更多
文摘The organization of the higher order structure of chromatin in chicken erythrocytes has been examined withtapping-mode scanning force microscopy under conditionsclose to their native environment. Reproducible highresolution AFM images of chromatin compaction at several levels can be demonstrated. An extended beads-on-astring (width of ～ 15-20nm, height of ～ 2-3nm for eachindividual nucleosome) can be consistently observed. Furthermore, superbeads (width of ～ 40nm, height of ～ 7nm)are demonstrated. Visualization of the solenoid conformation at the level of 30nm chromatin fiber is attained eitherby using AFM or by using electron microscopy. In addition, tightly coiled chromatin fibers (～ 50-60nm and ～90-110nm) can be revealed. Our data suggest that the chromatin in the interphase nucleus of chicken erythrocyte represents a high-order conformation and AFM provides useful high-resolution structural information concerning thefolding pattern of interphase chromatin fibers.
基金the financial support provided by the State Key Research Development Program of China (No.2016YFC0801406)the Natural Science Foundation of Jiangsu Province of China (No.BK20171191)National Natural Science Foundation of China(Nos.51674253,51734009)
文摘The mechanisms for rock bursts occurrences in fold zones are complex, and the redistribution of in-situ stresses is closely related to the complexity of the structures. Analysis of the geomorphology of fold structures and changes of coal thickness can help identify zones prone to rock bursts to improve safety and productivity in coal mines. This study investigated the distribution characteristics of fold structures in coal seams in fold zones in four mines in northwest China. Geometrical characteristics of fold structures in coal seams and changes of coal thickness were analysed, based on comprehensive evaluation indexes,such as the length–width ratio of folds, interlimb angle, ratio P1 of projected width of fold limbs to that of the hinge zone, curvature ratio P2, the maximum curvature and amplitude. The statistical analysis of the four coal mines shows that the length–width ratio of folds changed from 0.78 to 2.03 and the maximum curvature of cross sections of folds was less than 0.04. The curvature ratio of cross section of a fold in the structure was no more than 1.4 and the interlimb angles of cross sections of 89% of folds were larger than 150°. Gentle fold structures were dominant and the specific geological morphologies were domes or basins. The isopleth of coal thickness above the coal mines showed a fluctuation trend similar to the contour line of the floor of coal seams. The coal thickness in an anticline area was smaller than that in the neighboring syncline area. Therefore, the overall variation of coal thickness in the mining areas was likely to have a relation with the direction of the regional principal stress.
基金supported in part by National Key R&D Program of China(Grant No.2018YFB1304600)CAS Interdisciplinary Innovation Team(Grant No.JCTD-2018-11)the Natural Science Foundation of China(Grant No.51775541).
文摘Flasher origami pattern has been widely utilized to improve the stowage efficiency of deployable structures.Nevertheless,flasher origami cannot be folded fully flat,and they still have great potential for optimization in terms of storage volume and folding creases.In this paper,a flat foldable equiangular spiral folding pattern inspired by the sunflower disk is introduced.Then,a parametric design method for this equiangular spiral crease diagram is introduced in detail.Subsequently,a kinematic model of the equiangular spiral folding pattern is established based on the kinematic equivalence between rigid origami and spherical linkages.A simulation of the developed model demonstrates that the equiangular spiral folding pattern can be folded flat.Using the folded ratio as an evaluation index,the calculated results and experiments show that the equiangular spiral crease pattern can yield fewer creases and improve stowage efficiency in comparison to flasher origami pattern.Equiangular spiral folding pattern can save a considerable amount of space and provide a new approach to spatially deployable structures.
文摘The chromatin folding patterns in air and liquid were studied by atomicforce microscopy (AFM). A gentle water-air interface method was adopted to spreadchromatin from interphase nucleus of chicken erythrocyte. The chromatin was ah-sorbed on APS-Inica surfaCe and studied with AFM. Beads-on-a-string were observedand many higher-order structures such as superbeads with dimensions 40-60urn indiameter and 4-7 urn in height were found to string together to make chromatin fibers.When sample spreading and absorbing time were shortened, higher-order chromatinfibers with 60-120 urn in width were observed in air as well as under water environment. These chromatin structures may reflect chromatin folding patterns in the livingcells.
文摘The current geometric and thermodynamic approaches in protein folding studies do not provide a definite solution to understanding mechanisms of folding of biological proteins. A major problem is that the protein is first synthesized as a linear molecule that subsequently must reach its native configuration in an extremely short time. Hydrophobicity-hydrophilicity models and random search mechanism cannot explain folding to the 3-D functional form in less than 1 second, as it occurs in the intact cell. We propose an integral approach, based on the embedding of proteins in the whole cellular context under the postulate: a life protein is never alone. In this concept the protein molecule is influenced by various long and short distance force fields of nature such as coherent electromagnetic waves and zero-point energy. In particular, the role of solitons is reviewed in relation to a novel GM-scale biophysical principle, revealed by us. This recent finding of a set of discrete EM frequency bands, that either promote or endanger life conditions, could be a key in further studies directed at the morphogenetic aspects of protein folding in a biological evolutionary context. In addition, an alternative hypothesis is presented in which each individual cell may store integral 3-D information holographically at the virtual border of a 4-D hypersphere that surrounds each living cell, providing a field receptive memory structure that is instrumental in guiding the folding process towards coherently oscillating protein networks that are crucial for cell survival.
文摘Background: Microcirculation is affected in diabetes mellitus and Microvascular abnormalities cause persistent diabetic complications. The aim of this study was nailfold capillaroscopic assessment to describe the pathological changes (morphological and structural) in capillary of a large series of patients with type 1 and 2 diabetes. Methods: A cross-sectional study was carried out in a Nailfold Capillaroscopy Center (Tehran-Iran) between 2011 and 2014. The study included 235 types 1, 2 diabetic patients. All patients underwent 10 nailfolds capillaroscopy examinations. Microvascular architecture, disturbances capillary distribution, capillary morphology, capillary density, efferent/afferent limb ratio, subpapillary venular plexus, and morphological abnormalities were evaluated. Conclusions were stated as normalor scleroderma pattern. Results of patients’ capillaroscopic images were recorded and analyzed quantitatively and qualitatively. P value < 0.05 was considered as statistical significance. Results: of all participants with mean age 59.91 ± 12.39, 183 cases (77.9%) were female and 52 (22.1%) were male. Tortuosity of capillaries was more often observed in our subjects (235 cases) followed by angiogenesis (171 cases). Normal and early scleroderma patterns were observed in 195 (83.0%) and 40 cases (17.0%). Based on P values, altered micro vascular architecture, capillary distribution and capillary morphology were more frequent in patients with scleroderma pattern in comparison to patients with normal pattern (P value < 0.05). Morphological abnormalities except from neo formation capillary and mega capillary were also significantly more common in patients with scleroderma pattern than patients in counterpart group (P value < 0.05). Conclusion: Nailfold capillaroscopy as a non-invasive, diagnostic and prognostic method may potentially affect on diabetes outcome and control.
文摘This paper presents the design and the experimental characterization of a new multi-band antenna consisting of three folded monopoles dedicated to mobile communication systems. The originality of this paper is to get the PMR (Professional or Private Mobile Radio) band with the GSM (Global System for Mobile Communications), DCS (Digital Cellular System) and UMTS (Universal Mobile Telecommunications System) bands. The main lobe of the antenna radiates in the zenith direction with a linear polarization over all bands. It is interesting to design the proposed antenna in order to obtain better performances in terms of directive radiation pattern (especially in the PMR band) in comparison with the already existing antenna systems in the wireless market for similar purposes. The prototype was studied with the software CST-MWS (Micro wave studio 2012). The antenna has been designed and successfully measured.
文摘We have measured the angular distributions for 12C ion beam elastically scattered from 12C target of thickness 17.4 μg/cm2 at energies 15, 18 and 21 MeV which is close to the Coulomb barrier energy for 12C + 12C nuclear system. The elastic scattering of 12C beam on 12C was analysed also at different energies (139.5, 158.8, 180, 240, 288.6, 300, 360 and 420 MeV) from literature in order to obtain the global optical potential parameters, which could fairly reproduce the experimental data. The experimental results were analysed within the framework of both the optical model and the double folding potential obtained with different density-dependent NN interactions which give the corresponding values of the nuclear incompressibility K in the Hartree-Fock calculation of nuclear matter. The agreement between the experimental results and the theoretical predictions in the whole angular range is fairly good.
