Longitudinal Elongation Research Articles

Functional conservation of Arabidopsis LNG1 in tobacco relating to leaf shape change by increasing longitudinal cell elongation by overexpression.

The LONGIFOLIA1 (LNG1) gene of Arabidopsis regulates leaf shape by polar cell elongation independent of ROTUNDAFOLIA3 (ROT3). To expand our knowledge on the function of this gens in plant systems, Arabidopsis LNG1 (AtLNG1) was introduced both sense and antisense orientation under the control of 35S CaMV promoter into tobacco plants that lack AtLNG1 homolog. Resulting transgenic tobacco plants were analyzed by their phenotype, anatomy and transcript levels. AtLNG1-overexpressing tobacco lines showed increase in the leaf petiole and leaf blade compared with wild type tobacco line. The overexpressors also showed elongated palisade cells as well as epidermal cells in the leaf length direction, but no increase in cell number. Ectopic expression of AtLNG1 in tobacco plants also increased the expression of cell wall modification-related genes, such as NT_XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE9 (NT_XTH9), NT_XTH15 and NT_XTH33, indicating that these genes appear to be target of AtLNG1. As results of molecular and cellular examination, AtLNG1 seemed to have a conserved functional role in shaping leaf morphology in both Arabidopsis and tobacco.

Do adult trees increase conspecific juvenile resilience to recurrent droughts? Implications for forest regeneration

AbstractRecruitment is a bottleneck for forest regeneration especially in semi‐arid Mediterranean environments. Ensuring natural forest regeneration is vital for preserving ecosystem function under climate warming and increased frequency and intensity of extreme droughts. Interspecific positive interactions are of paramount importance in these ecosystems. The net outcome of conspecific plant interactions in semi‐arid forests, however, has been less explored, particularly the range of environmental conditions for which juveniles benefit from nursing effects. We evaluated the direction and magnitude of intraspecific relationships between adults and juveniles of Pinus pinaster in a dry continental Mediterranean forest in the Iberian Peninsula. We measured the longitudinal shoot elongation of the last 15 yr and foliar functional traits in pine saplings growing under the canopy of adult pines and in open habitats. We examined the growth response to precipitation and the resilience and resistance of growth to two extreme drought events in 2005 and 2012. Our results show likely facilitation of saplings by adult conspecifics. Nursed saplings had a greater size relative to age, longer needles, and faster shoot elongation than saplings in open habitats. In addition, saplings under the canopy were more resistant and resilient to the first severe drought event. However, saplings grown in open habitats were more resilient to the second drought event, which might suggest a shift in the net balance of conspecific interactions with increased drought frequency and with tree ontogeny. These results have a direct application for the adaptation and restoration of semi‐arid forest ecosystems under climate change. Currently, adults are used as nurse plants to enhance survival and growth of juveniles. However, this positive effect on sapling performance might shift to negative under scenarios of increasing frequency and intensity of drought events.

Effect of micromechanical parameters of composites with wavy fibers on their effective response under large deformations

The large deformation response of composites reinforced by continuous wavy fibers is investigated using three-dimensional Finite Element Analysis. The focus is placed on in-phase fibers with circular cross-sections following sinusoidal paths. The effects of the following micromechanical parameters are analyzed – relative fiber radius, fiber crimp ratio, fiber arrangement and matrix material compressibility. In addition, the responses predicted by three-dimensional and two-dimensional plane strain models are compared. The considered composite is modeled as a fully periodic wavy unit cell subjected to periodic boundary conditions and three load cases – elongations in the x1 (longitudinal) and x2 (transverse) directions, and simple shear in the x1–x2 plane. Both constituents of the composite, the fibers and the matrix, are modeled using an isotropic hyperelastic material formulation. The results are presented as plots of macroscopic Cauchy stress components versus applied stretch (or strain in the case of the shear loading) and of fiber undulation versus applied stretch for the longitudinal elongation.

Functionally redundant LNG3 and LNG4 genes regulate turgor-driven polar cell elongation through activation of XTH17 and XTH24.

In this work, we genetically characterized the function of Arabidopsis thaliana, LONGIFOLIA (LNG1), LNG2, LNG3, LNG4, their contribution to regulate vegetative architecture in plant. We used molecular and biophysical approaches to elucidate a gene function that regulates vegetative architecture, as revealed by the leaf phenotype and later effects on flowering patterns in Arabidopsis loss-of-function mutants. As a result, LNG genes play an important role in polar cell elongation by turgor pressure controlling the activation of XTH17 and XTH24. Plant vegetative architecture is related to important traits that later influence the floral architecture involved in seed production. Leaf morphology is the primary key trait to compose plant vegetative architecture. However, molecular mechanism on leaf shape determination is not fully understood even in the model plant A. thaliana. We previously showed that LONGIFOLIA (LNG1) and LONGIFOLIA2 (LNG2) genes regulate leaf morphology by promoting longitudinal cell elongation in Arabidopsis. In this study, we further characterized two homologs of LNG1, LNG3, and LNG4, using genetic, biophysical, and molecular approaches. Single loss-of-function mutants, lng3 and lng4, do not show any phenotypic difference, but mutants of lng quadruple (lngq), and lng1/2/3 and lng1/2/4 triples, display reduced leaf length, compared to wild type. Using the paradermal analysis, we conclude that the reduced leaf size of lngq is due to decreased cell elongation in the direction of longitudinal leaf growth, and not decreased cell proliferation. This data indicate that LNG1/2/3/4 are functionally redundant, and are involved in polar cell elongation in Arabidopsis leaf. Using a biophysical approach, we show that the LNGs contribute to maintain high turgor pressure, thus regulating turgor pressure-dependent polar cell elongation. In addition, gene expression analysis showed that LNGs positively regulate the expression of the cell wall modifying enzyme encoded by a multi-gene family, xyloglucan endotransglucosylase/hydrolase (XTH). Taking all of these together, we propose that LNG related genes play an important role in polar cell elongation by changing turgor pressure and controlling the activation of XTH17 and XTH24.

A study of the effect of fiber orientation on the torsional behavior of RC beams strengthened with PBO-FRCM composite

Repair and rehabilitation of reinforced concrete (RC) structures with different types of external reinforcement has been investigated widely. Fiber reinforced cementitious matrix (FRCM) is a new type of composite system that contains continuous fibers embedded in inorganic matrix. This system has been proven to be effective for strengthening RC members under flexure, shear, and axial loadings. However, studies on the use of FRCM composite for torsional strengthening are very limited. This study investigated experimentally the torsional behavior of solid rectangular RC beams strengthened with externally bonded PBO-FRCM composite in different wrapping configurations. The study focused on the effect of fiber orientation as well as other parameters that influence the torsional strength, torsional moment-twist per unit length response, and mode of failure including fiber continuity and number of composite layers. The strains in the internal and external reinforcement and the longitudinal elongation of the strengthened beams were examined, and a comparison with other types of fiber reinforced composite was also discussed. The 90° fiber orientation (perpendicular to the beam longitudinal axis) was more effective in increasing the torsional strength than the 45° fiber orientation since premature debonding of the fibers occurred at the ends of the 45° strips, which contrasted the potential benefits from optimizing the fiber orientation and led to the underutilization of the composite. The 90° fiber orientation was also more effective than the 0° fiber orientation.

System organization of disjunctive tectonics of consolidated basement in Dnipro-Donets paleorift. Part 3. Structural-cinematic parageneses of horizontal-shear dislocations zones

Formulation of the problem. Getting knowledge of the processes and mechanisms of the rocks tectonic flow is important both for geotectonics and for oil and gas geology as horizontal displacements and rotation of geological blocks in creep dislocations form secondary deformation structures. Zones of both raised and reduced tectonic stresses are formed in the structural and kinematic parageneses - the so-called shadow geodynamic zones, in which active fluid-dynamic processes contributing to traps formation and accumulation of hydrocarbons in them, are formed. Objects of research are secondary deformation structures of tectonic flow (STF). Their newest structural-kinematic parageneses and structured drawings on the surface of Precambrian crystalline basement were studied. Horizontal strike-slip dislocations create their modern architectural structure together with relics of the riftogenic structure. The purpose of the article. The aim of the research is to study structural manifestation of collisional post-tectonic tectogenesis processes in the architectural structure of the DDP crystalline basement. The research tasks are: - To study the types of tectonic movements and mechanisms of tectonic flow deformations in the foundation and identification of the structural patterns; - To diagnose morphogenetic types of strike-slip deformation structures of the basement and structural-kinematic parageneses of tectonic flow. Methods. According to Plates tectonics theory the tectonic-physics method of structural drawings analysis was used to study the basement tectonics. It allows us to diagnose tectonic movements and deformations of geomass, in particular, its longitudinal, transverse and rotational displacement relative to the extension of the paleoriff structure in various kinematic forms of bending in the horizontal plane, extrusion and injection, as well as the adjoining movements of domains - groups of horizontal strike-slip faults ensembles and their created geological blocks. Results. According to the results of regional tectonophysical studies: It is established that considerable internal tectonic mobility of the Precambrian foundation at the newest stage of the DDP evolution is manifested in the formation of horizontal strike-slip dislocations zones in the regional system of faults activated in the latest geodynamic stress field. The processes and mechanisms of collision tectonics, which caused formation in the knot zones of the deformation structures of the tectonic flow and the formation of strike-slip structural and kinematic parageneses, have been studied. They are reflected in the tectonic plan of the foundation in the form of characteristic structural elements of the structure and determine its modern architectural structure. The three basic tectonophysical mechanisms of horizontal strike-slip islocations, which differ in kinematics and directions of joint horizontal displacements of block domains, relative to the axis of the paleorief strike, are distinguished: - longitudinal elongation under the mechanism of joint antithyroid rotations of blocks on systems of diagonal strike-slip faults; - transverse extension of the mechanism of joint synthetic rotation of blocks on systems of orthogonal and diagonal shifts, as well as their complex combination without the rotation of the duplex blocks; - tectonic megabout by means of coordinated reciprocating movements without rotational component of adjacent blocks along kinematically identical sub-parallel strike-slip faults. Scientific novelty and practical significance . In the framework of the newest zones of horizontal strike-slip dislocations, three genesic types of structurally-kinematic parageneses, which correspond to the main geodynamic conditions, are established: – contractional duplexes that form ensembles of longitudinal and transverse to reach the paleiorief of positive forms-«palm tree» on the surface of the foundation -structural-tectonic and embrio-tectonic arcs; – extensional duplexes of the sprawl, forming the negative forms- «flower structures» or pull-apart basine - lens-like minigrabens; geological blocks - megabodies of oval form, forming local depressions in the relief of the foun-dation.

Wide-band Electrical Impedance Spectroscopy (EIS) Measures S. pombe Cell Growth in vivo.

This chapter describes a microfluidic device that enables immobilization and culturing of single rod-shaped S. pombe cells in a stand-up mode. The wide-band electrical impedance spectroscopy (EIS) has been integrated in the microfluidic device to continuously measure cell growth of single S. pombe cells. Cell growth curves showing cellular and intracellular features at high spatiotemporal resolution can be obtained from EIS signals. The features include longitudinal cell elongation in the G2 phase, mitosis, and cell division during an entire cell cycle of S. pombe cells. Microfluidics-based EIS systems provide, hence, a tool for dynamic single-cell studies.

Impact of post-dilatation on longitudinal stent elongation: An in vitro study

ObjectivesTo evaluate whether balloon inflation for post-dilatation causes longitudinal stent deformation (LSD). Methods and resultsTwo stents, sized 2.5mm×28mm and 3.5mm×28mm (Nobori®, biodegradable polymer biolimus-eluting stent; Ultimaster®, biodegradable polymer sirolimus-eluting stent; Terumo Co., Tokyo, Japan), were deployed at nominal pressure in straight and tapered silicon vessel models. Then, post-dilatation was performed in two ways: dilatation from the distal (D-P group) or proximal (P-D group) side of the stent. Microscopic findings showed that the stents were elongated during every step of the procedure regardless of the post-dilatation method and type of vessel model. The D-P group showed linear elongation during each step of post-dilatation (straight model: 28.7±0.3mm vs. 29.9±0.3mm, p=0.002; tapered model: 28.0±0.1mm vs. 29.9±0.1mm, p<0.001). In contrast, in the P-D group, the most significant change was observed in the first step of post-dilatation and only slight changes were observed thereafter (straight model: 28.6±0.1mm vs. 29.5±0.1mm, p<0.001; tapered model: 28.2±0.1mm vs. 29.5±0.1mm, p<0.001). Optical frequency domain imaging analysis showed that the frequency of stent strut malapposition was positively correlated with the percentage change in stent length (r=0.74, p<0.0001). ConclusionLSD was observed during every step of post-dilatation in both the straight and tapered vessel models. However, some differences were observed between the D-P and P-D groups. Minimizing stent strut malapposition may reduce the risk of LSD.

Nitrate induction of root hair density is mediated by TGA1/TGA4 and CPC transcription factors in Arabidopsis thaliana.

Root hairs are specialized cells that are important for nutrient uptake. It is well established that nutrients such as phosphate have a great influence on root hair development in many plant species. Here we investigated the role of nitrate on root hair development at a physiological and molecular level. We showed that nitrate increases root hair density in Arabidopsis thaliana. We found that two different root hair defective mutants have significantly less nitrate than wild-type plants, suggesting that in A.thaliana root hairs have an important role in the capacity to acquire nitrate. Nitrate reductase-null mutants exhibited nitrate-dependent root hair phenotypes comparable with wild-type plants, indicating that nitrate is the signal that leads to increased formation of root hairs. We examined the role of two key regulators of root hair cell fate, CPC and WER, in response to nitrate treatments. Phenotypic analyses of these mutants showed that CPC is essential for nitrate-induced responses of root hair development. Moreover, we showed that NRT1.1 and TGA1/TGA4 are required for pathways that induce root hair development by suppression of longitudinal elongation of trichoblast cells in response to nitrate treatments. Our results prompted a model where nitrate signaling via TGA1/TGA4 directly regulates the CPC root hair cell fate specification gene to increase formation of root hairs in A.thaliana.

Non-linear stress-orientation behavior of flexible chain polymers under fast elongational flow

Closed-form analytical formulas are proposed for non-linear stress-orientation relation valid in the entire range of tensile stresses, intermediate and high, basing on the inverse Langevin chain statistics. Tensile force and orientation characteristics for single, flexible chain macromolecule are reconsidered in a closed-form Padè approximation of the inverse Langevin function in the entire range of chain extensions, as well as the dynamics of molecular deformation and orientation for systems of chains subjected to uniaxial elongational flow. Average stress and orientation tensors, not collinear in the non-linear range, as well as the tensile stress and axial orientation factor of the chain segments in the system are calculated. For the intermediate tensile stresses, the closed-form formula is derived in the first non-Gaussian term approximation of the inverse Langevin function with the assumption of dominating longitudinal elongation of the chains. The high-stress non-linearity formula is derived with the Padè and Peterlin modulus approximations and aligned chain end-to-end vectors by the flow. Both formulas are validated by exact numerical calculations without the assumptions and influence of the approximations is estimated. Ranges of applicability of the formulas are illustrated and examples of their application are presented.

Wet-spinning fabrication of shear-patterned alginate hydrogel microfibers and the guidance of cell alignment.

Native tissue is naturally comprised of highly-ordered cell-matrix assemblies in a multi-hierarchical way, and the nano/submicron alignment of fibrous matrix is found to be significant in supporting cellular functionalization. In this study, a self-designed wet-spinning device appended with a rotary receiving pool was used to continuously produce shear-patterned hydrogel microfibers with aligned submicron topography. The process that the flow-induced shear force reshapes the surface of hydrogel fiber into aligned submicron topography was systematically analysed. Afterwards, the effect of fiber topography on cellular longitudinal spread and elongation was investigated by culturing rat neuron-like PC12 cells and human osteosarcoma MG63 cells with the spun hydrogel microfibers, respectively. The results suggested that the stronger shear flow force would lead to more distinct aligned submicron topography on fiber surface, which could induce cell orientation along with fiber axis and therefore form the cell-matrix dual-alignment. Finally, a multi-hierarchical tissue-like structure constructed by dual-oriented cell-matrix assemblies was fabricated based on this wet-spinning method. This work is believed to be a potentially novel biofabrication scheme for bottom-up constructing of engineered linear tissue, such as nerve bundle, cortical bone, muscle and hepatic cord.

In situ observation of tensile behavior in a single silicon nano-helix grown by glancing angle deposition

In order to investigate the mechanical properties of amorphous silicon helical nanoelements (nano-helices), grown by the glancing angle deposition (GLAD) technique, we conducted tensile testing experiments on single nano-helices, which focused on the proof-of-principle. Three isolated nano-helices were prepared from the same GLAD layer by the removal of adjacent nano-helices using a nano-probe, and the top end was adhered to the loading tip with an electron beam curing adhesive. In situ observation by scanning electron microscopy revealed that the single nano-helix underwent a large longitudinal elastic elongation until fracture (about 40% of the fracture displacement) owing to its helical shape. In the early stage of deformation, there was a jump in the load-displacement relationship, due to partial breaking of the connecting leg at the root of the nano-helix. The tension induced plastic deformation and fracture in the bottom zone where the wire diameter was smaller. Examination based on element geometry at local zones indicated that deformation in the elastic stage was governed by the element shape. The yield stress of the amorphous silicon for the nano-helix was estimated to be approximately 0.8GPa.

Behaviour of continuous concrete filled steel tubular columns loaded concentrically in fire

Design recommendations for concrete filled steel tubular (CFST) columns in fire are based on the results of experimental standard fire testing of CFST members where the same temperature is applied to the column over the full column height. However, this is not representative of a CFST column in a typical building, which is continuous between floors and which, in fire, is subjected to severe fire conditions on one floor at a time while the floors above and below remain cooler. In the experimental tests described in this paper, the columns are of 3.2m height with the fire applied only to the central 2m. Significant differences are observed between these tests and those previously conducted due to the partial length heating. In total, ten tests are conducted; the tests cover three different types of infill: plain concrete; bar reinforced concrete; and steel fibre reinforced concrete. End restraint conditions of fixed-fixed (F-F) and pinned-fixed (P-F) are considered; the axial load levels are between 0.33 to 0.38 of the squash load. The longitudinal elongation of the steel tube was less than 3mm. Using the experimentally measured structural fire resistance (R), the axial capacity in fire was calculated in accordance with the codes of practice and are Compared with the experimentally tested structural fire resistance, showing that in some instances current design practice can be un-conservative.

A single-nucleotide polymorphism causes smaller grain size and loss of seed shattering during African rice domestication.

Grain size is one of the most important components of grain yield and selecting large seeds has been a main target during plant domestication. Surprisingly, the grain of African cultivated rice (Oryza glaberrima Steud.) typically is smaller than that of its progenitor, Oryza barthii. Here we report the cloning and characterization of a quantitative trait locus, GL4, controlling the grain length on chromosome 4 in African rice, which regulates longitudinal cell elongation of the outer and inner glumes. Interestingly, GL4 also controls the seed shattering phenotype like its orthologue SH4 gene in Asian rice. Our data show that a single-nucleotide polymorphism (SNP) mutation in the GL4 gene resulted in a premature stop codon and led to small seeds and loss of seed shattering during African rice domestication. These results provide new insights into diverse domestication practices in African rice, and also pave the way for enhancing crop yield to meeting the challenge of cereal demand in West Africa.

TCTAP C-262 Acute Coronary Syndrome Resulted in Longitudinal Stent Elongation During Post-dilatation with Semi-compliant Balloon and Subsequent Thrombus-shift Derived from Culprit Lesion

TCTAP C-262 Acute Coronary Syndrome Resulted in Longitudinal Stent Elongation During Post-dilatation with Semi-compliant Balloon and Subsequent Thrombus-shift Derived from Culprit Lesion

Stability of electrical properties for mechanically exposed thick- and thin-film resistors on flexible substrates

PurposeThe paper aims to verify the influence of mechanical factors (longitudinal elongation at constant stretching velocity, constant elongation strain and cyclic compressive and tensile stresses) on the electrical properties of thin-film and polymer thick-film resistors on flexible substrates.Design/methodology/approachKapton foil was used as a substrate for all test samples. Designed resistive structures were made with the aid of two polymer thick-film resistive inks or OhmegaPly Ni-P resistive foil. Two different topologies – the horseshoe and triangular – were used. These topologies should have the opposite stability parameters.FindingsAlmost all presented data confirm the influence of the topology of resistors on stability of their electrical properties. The resistive materials applied for test structures also affect the stability under various mechanical exposures.Originality/valueIn general, the largest changes were caused by longitudinal elongation at constant stretching velocity, whereas other tests caused smaller changes of electrical properties. The measurements confirm the influence of topology on stability of electric properties.

Catechol, a major component of smoke, influences primary root growth and root hair elongation through reactive oxygen species-mediated redox signaling.

Nicotiana attenuata germinates from long-lived seedbanks in native soils after fires. Although smoke signals have been known to break seed dormancy, whether they also affect seedling establishment and root development remains unclear. In order to test this, seedlings were treated with smoke solutions. Seedlings responded in a dose-dependent manner with significantly increased primary root lengths, due mainly to longitudinal cell elongation, increased numbers of lateral roots and impaired root hair development. Bioassay-driven fractionations and NMR were used to identify catechol as the main active compound for the smoke-induced root phenotype. The transcriptome analysis revealed that mainly genes related to auxin biosynthesis and redox homeostasis were altered after catechol treatment. However, histochemical analyses of reactive oxygen species (ROS) and the inability of auxin applications to rescue the phenotype clearly indicated that highly localized changes in the root's redox-status, rather than in levels of auxin, are the primary effector. Moreover, H2 O2 application rescued the phenotype in a dose-dependent manner. Chemical cues in smoke not only initiate seed germination, but also influence seedling root growth; understanding how these cues work provides new insights into the molecular mechanisms by which plants adapt to post-fire environments.

The influence of distortion on enhancing the registration accuracy in roll-to-roll printing processes

An empirical equation accurately predicting the distortion of a printed image on a plastic substrate was formulated. Experiments were performed to isolate parameters and evaluate each factor independently. An empirical equation that accounted for the tension, temperature and web speed was formulated. The substrate strain rate showed a linear dependency with the temperature and the tension, and increased exponentially with the web speed. Due to the differences between real image value and experimental error, a compensation factor was added to the empirical equation. In order to validate this empirical equation, we also performed experiments on substrates with different radial and longitudinal elongation rates. It was concluded that the elongation of the substrate does not affect the image strain rate. Experiments with a thicker substrate and a higher elongation rate confirmed that the image strain rate is more significantly affected by the thickness of the film than the elongation of the substrate. This empirical equation can be utilized to predict the image size at different conditions, and the registration accuracy can be improved by predicting the distortion during the processing.

Pattern analysis of a linear dune field on the northern margin of Qarhan Salt Lake, northwestern China

In terms of formation mechanisms of linear dunes, there are open arguments for their widespread distribution and multi-morphological diversities. In order to clarify the formation mechanism of linear dunes of Qarhan Salt Lake, we used pattern analysis method to analyze the statistical characteristics and spatial variation of their pattern parameters. Except at the west-northwest margin, the pattern parameters showed regular spatial variation from the up-middle part towards the downwind end of the dune field. Based on the cumulative probability plots for inter-crest spacing and crest length, we divided the linear dunes into three groups, which corresponding to the three evolution stages of these dunes. The first group comprises erosional relics, with shorter crests, smaller inter-crest spacing and more random dune orientation. The second group comprises dunes whose sand supply is just sufficient to maintain stability and these dunes are approaching the net erosion stage. The crest length and inter-crest spacing of these dunes are much larger than those of the first group, and dune orientation is closer to the resultant drift direction (RDD). The last group comprises linear dunes that are still undergoing vertical accretion and longitudinal elongation, which follows the RDD of the modern wind regime. The presence of regular spatial variation of pattern parameters and a similar geometry with the vegetated linear dunes suggest that deposition and erosion coexist in the development and evolution of linear dunes of Qarhan Salt Lake, i.e. deposition predominates at the downwind end of linear dunes in the vertical accretion and longitudinal elongation stage, whereas erosion mainly occurs at the upwind end of linear dunes in the degradation stage. Therefore, the formation mechanism of linear dunes in Qarhan Salt Lake can be reasonably explained by the combination of depositional and erosional theories.

TCTAP C-116 Longitudinal Stent Elongation from ‘LAD' to ‘LMCA' During Retraction of Entrapped Jailed Guidewire from Diagonal Side Branch

### Patient initials or identifier number PS ### Relevant clinical history and physical exam Mr. PS 37 years non-diabetic, non-hypertensive male presented with exertional chest pain (CCS-Class-II) for 3 months. He is smoker, dyslipidaemic and hyperuricaemic. His mother died suddenly at the age of