Element Stress Research Articles

Comprehensive Analysis of BR Receptor Expression under Hormone Treatment in the Rubber Tree (Hevea brasiliensis Muell. Arg.).

Brassinosteroids (BRs) are important for plant growth and development, with BRI1 and BAK1 kinases playing an important role in BR signal transduction. Latex from rubber trees is crucial for industry, medicine and defense use. Therefore, it is beneficial to characterize and analyze HbBRI1 and HbBAK1 genes to improve the quality of the resources obtained from Hevea brasiliensis (rubber tree). Based on bioinformatics predictions and rubber tree database, five HbBRI1s with four HbBAK1s were identified and named HbBRI1~HbBRL3 and HbBAK1a~HbBAK1d, respectively, which were clustered in two groups. HbBRI1 genes, except for HbBRL3, exclusively contain introns, which is convenient for responding to external factors, whereas HbBAK1b/c/d contain 10 introns and 11 exons, and HbBAK1a contains eight introns. Multiple sequence analysis showed that HbBRI1s include typical domains of the BRI1 kinase, indicating that HbBRI1s belong to BRI1. HbBAK1s that possess LRR and STK_BAK1_like domains illustrate that HbBAK1s belong to the BAK1 kinase. BRI1 and BAK1 play an important role in regulating plant hormone signal transduction. Analysis of the cis-element of all HbBRI1 and HbBAK1 genes identified hormone response, light regulation and abiotic stress elements in the promoters of HbBRI1s and HbBAK1s. The results of tissue expression patterns indicate that HbBRL1/2/3/4 and HbBAK1a/b/c are highly expressed in the flower, especially HbBRL2-1. The expression of HbBRL3 is extremely high in the stem, and the expression of HbBAK1d is extremely high in the root. Expression profiles with different hormones show that HbBRI1 and HbBAK1 genes are extremely induced by different hormone stimulates. These results provide theoretical foundations for further research on the functions of BR receptors, especially in response to hormone signals in the rubber tree.

Genome-Wide Analysis, Characterization, Expression and Function of SERK Gene Family in Phyllostachys edulis

Somatic mmbryogenesis receptor-like kinase (SERK) is a kind of protein kinase widely distributed in plants. It plays a vital role in regulating plant immunity and responses to abiotic stress. The SERK gene family has not been systematically studied in moso bamboo (Phyllostachys edulis). In this study, we identified six PeSERK genes and classified them into four groups in moso bamboo. PeSERKs of each group shared a highly similar distribution of conserved domains. Cis-element analysis indicated that many stress and hormone response elements are distributed on the promoters of PeSERKs. Moreover, we analyzed the chromosomal locations and synteny of PeSERKs. A collinear gene pair, PeSERK1 and PeSERK3, shared a high similarity, 93%, and the expression analysis showed similar expression patterns. Compared to PeSERK3, PeSERK1 had a higher expression in all tissues examined and all stages of shoot development. PeSERK3 was expressed mainly in leaf sheaths but with a low expression in other tissues. The expressions of PeSERKs were analyzed in seedlings under abiotic and hormone treatments using qRT-PCR. Except for PeSERK1 and PeSERK3, the expressions of most genes were downregulated or had no big difference at 0 h of drought treatment. Under drought treatment, PeSERK1 and PeSERK3 had a similar expression trend of increasing first and then decreasing. However, the expression level of PeSERK3 was higher than PeSERK1 after 3 h of drought treatment. PeSERK3 might play a more vital role in the drought stress response than PeSERK1. This study provides a theoretical basis for the further study of the SERK response to stress conditions in moso bamboo.

Exploring relationships between physician stress, burnout, and diagnostic elements in clinician notes.

To understand the relationship between stressful work environments and patient care by assessing work conditions, burnout, and elements of the diagnostic process. Notes and transcripts of audiotaped encounters were assessed for verbal and written documentation related to psychosocial data, differential diagnosis, acknowledgement of uncertainty, and other diagnosis-relevant contextual elements using 5-point Likert scales in seven primary care physicians (PCPs) and 28 patients in urgent care settings. Encounter time spent vs time needed (time pressure) was collected from time stamps and clinician surveys. Study physicians completed surveys on stress, burnout, and work conditions using the Mini-Z survey. Physicians with high stress or burnout were less likely to record psychosocial information in transcripts and notes (psychosocial information noted in 0% of encounters in 4 high stress/burned-out physicians), whereas low stress physicians (n=3) recorded psychosocial information consistently in 67% of encounters. Burned-out physicians discussed a differential diagnosis in only 31% of encounters (low counts concentrated in two physicians) vs. in 73% of non-burned-out doctors' encounters. Burned-out and non-burned-out doctors spent comparable amounts of time with patients (about 25min). Key diagnostic elements were seen less often in encounter transcripts and notes in burned-out urgent care physicians.

Experimental Research and Numerical Simulation of Laser Welding of 303Cu/440C-Nb Stainless-Steel Thin-Walled Natural-Gas Injector for Vehicles.

This paper presents the results of research on laser lap welding technology of heterogeneous materials and a laser post-heat treatment method to enhance welding performance. The purpose of this study is to reveal the welding principle of austenitic/martensitic dissimilar stainless-steel materials (3030Cu/440C-Nb) and to further obtain welded joints with good mechanical and sealing properties. A natural-gas injector valve is taken as the study case where its valve pipe (303Cu) and valve seat (440C-Nb) are welded. Experiments and numerical simulations were conducted where the welded joints' temperature and stress fields, microstructure, element distribution, and microhardness were studied. The results showed that the residual equivalent stresses and uneven fusion zone tend to concentrate at the joint of two materials within the welded joint. The hardness of the 303Cu side (181.8 HV) is less than the 440C-Nb side (266 HV) in the center of the welded joint. The laser post-heat treatment can reduce the residual equivalent stress in the welded joint and improve the mechanical and sealing properties. The results of the press-off force test and the helium leakage test showed that the press-off force increased from 9640 N to 10,046 N and the helium leakage rate decreased from 3.34 × 10-4 to 3.96 × 10-6.

An Assessment of Stress in an Intensive Care Unit (ICU): An Exploratory Study Utilising Self-Assessment, Physiological, and Salivary Cortisol Measures

The study investigates exposure to stress by respondents working in an Intensive Care Unit (ICU) and differences in using three instruments to measure stress. The survey was conducted from September to October 2018 in Dubrava Clinical Hospital in the ICU unit, with forty-one (41) healthcare professionals. Three forms of testing were set up: self-evaluation of stress, measurements of physiological indicators, and cortisol levels. The results show a statistically significant difference in mean cortisol levels, with the first sample much higher than other samples. There were significant interactions between skin conduction (SC) and stress levels, where all participants exhibited increases in SC. Heart rate variability (HRV) shows a slight correlation with stress levels in the group possessing substantially more stress experience. Although some differences were observed, all stress elements for professionals working in ICUs indicates that they cope well with stressful situations.

Artificial instabilities of finite elements for nonlinear elasticity: Analysis and remedies

SummaryWithin the framework of plane strain nonlinear elasticity, we present a discussion on the stability properties of various Enhanced Assumed Strain (EAS) finite element formulations with respect to physical and artificial (hourglassing) instabilities. By means of a linearized buckling analysis we analyze the influence of element formulations on the geometric stiffness and provide new mechanical insights into the hourglassing phenomenon. Based on these findings, a simple strategy to avoid hourglassing for compression problems is proposed. It is based on a modification of the discrete Green‐Lagrange strain, simple to implement and generally applicable. The stabilization concept is tested for various popular element formulations (namely EAS elements and the assumed stress element by Pian and Sumihara). A further aspect of the present contribution is a discussion on proper benchmarking of finite elements in the context of hourglassing. We propose a simple bifurcation problem for which analytical solutions are readily available in the literature. It is tailored for an in‐depth stability analysis of finite elements and allows a reliable assessment of its stability properties.

МЕТОД ПІДТВЕРДЖЕННЯ РЕСУРСНИХ ХАРАКТЕРИСТИК МЕТАЛЕВОЇ ЛОПАТІ НЕСУЧОГО ГВИНТА ВЕРТОЛЬОТА ЗА РЕЗУЛЬТАТАМИ ВИПРОБУВАНЬ

The helicopter main rotor blade is the basic product that determines the reliability and service life of the helicopter as a whole. The problem of predicting and ensuring the specified blade life is an urgent problem considered at the stage of its design. The analysis of the design, structural materials and design and technological solutions of the main rotor blade (RB) of the Mi-8 helicopter has been carried out. A brief description of the main rotor blade of the Mi-8 helicopter is presented. The analysis was carried out and a standard flight cycle (SFC) of the helicopter was developed. The type of bench equipment for carrying out bench fatigue tests of the blade has been selected and justified. The loads on the main rotor blade for the SFC are determined. To determine the fatigue life of a blade, it is necessary to know the characteristics of the stress-strain state. The calculation of the stress-strain state (SSS) of a blade by the finite element method (FEM) using the ANSYS system is presented. The characteristics of the stress-strain state of the spar of the regular and irregular parts of the rotor blade of a helicopter are determined using the ANSYS system. The use of numerical methods for calculating the characteristics of the stress-strain state can significantly reduce the time and cost of designing a blade. The paper presents the results of calculating the regular part of the main rotor blade of the Mi-8 helicopter in the hover mode in the case of its loading with aerodynamic and inertial load from rotation, as well as the force from its own weight. With the help of the ANSYS system, a finite element model of the regular part of the blade was developed, consisting of a set of beam elements of variable section, a calculation was carried out taking into account the geometric nonlinearity of the structure's behavior, and an analysis of the results obtained was carried out. To describe the response of materials to an external action, a model of an elastically deformable isotropic body was used with the assignment of the corresponding elastic constants of the material. The analysis of the calculation results includes the determination of reactions at the attachment points, the values of the maximum displacements of structural elements and stresses in dangerous sections. Dangerous sections are determined and the values of the longitudinal force and bending moment in these sections are calculated. The assessment of the static strength of the blade by the safety factor was carried out. When evaluating the static strength, the equivalent stresses according to Mises were considered as the maximum design stresses. To assess the fatigue strength, we analyzed the distribution of the main tensile stresses in the power elements over typical stress concentrators. The maximum level of the main tensile stresses in the dangerous section indicates that the blade material operates in the zone of high-cycle fatigue. A technique for calibrating strain gauge channels has been developed. The calculation of the characteristics of the rotor blade of a helicopter is based on the requirements set forth in the technical literature, regulatory documents. When performing work, the requirements of the Aviation Rules, Part 29 (AP - 29) were taken into account. These studies were the basis for the development of a method for confirming the resource characteristics of a helicopter main rotor blade based on the results of flight and bench tests.

An evaluation of trace elements and oxidative stress in patients with benign paroxysmal positional vertigo.

Vertigo and Dizziness are a common complaint among the reasons for applying to the ear nose throat clinic. Benign Paroxysmal Positional Vertigo (BPPV) is the most common cause of perpheric vertigo. Oxidative stress is caused by the formation of hydroxyl radicals, superoxide anions and hydrogen peroxide, which are reactive oxygen derivatives (ROS). The aim of this study is to investigate the relationship between complaints and serum trace element and oxidative stress levels in patients with BPPV. This study was conducted with 66 adult patients who presented to the ENT policlinic with the complaint of vertigo and were diagnosed with BPPV between May 2020 and September 2020. Blood samples were taken from patients diagnosed with BPPV to measure serum Zn and Cu levels and oxidative stress levels during an attack. The mean ages of the study patients and healthy controls were 45.7 ± 15.1 and 44.7±13.2. Female / Male ratio were 28(42.5%)/38(57.5%) and 32(48.5%)/34(51.5%) in study and control group. We found serum Cu levels were lower in the patient group (p <0.05). Serum Total Thiol and Native Thiol values were lower in patients with BPPV. Total Thiol results were statistically significant.(p<0.05) Disulfide values were significantly higher in the disease group. (P <0.05). Thiol Oxidized / Thiol Reduced ratio (2243.6±6.7/343.8±125.3) was higher in control group. (p<0.05). Serum oxidative stress and trace elements play a role in the pathophysiology of BPPV. We present the cut-off values for Cu and Zn in vertigo patients for the first time in the literature. We think that these cut-off values of the trace elements and thiol/disulfide hemostasis can be used clinically by physicians in the etiology, diagnosis and treatment of vertigo.

Effect of cooling rate on the order degree, residual stress, and room temperature mechanical properties of Fe-6.5wt.%Si alloy

The top side-pouring twin-roll casting (TSTRC) process was used to prepare a 100 × 1.7 mm non-oriented Fe-6.5 wt% Si alloy as-cast strip. The as-cast strip is directly rolled at 700 °C into 0.4 mm without the intermediate hot rolling step. This paper discusses the effects of different cooling rates in furnace cooling, air cooling, oil quenching, and water quenching on the order degree, residual stress, room temperature mechanical properties, and cold-rolled processing properties of Fe-6.5wt.%Si alloy after annealing of warm-rolled sheets are systematically investigated. Meanwhile, the effects of order degree, residual stress, and grain boundary element segregation on the mechanical properties were analyzed. The results show that as the cooling rate increases, the order degree of the Fe-6.5 wt% Si alloy decreases and the maximum residual tensile stress increases. The fracture modes of the furnace cooling, air cooling, and oil quenching samples are through-crystal disintegration fracture, and the fracture mode of the water quenching samples is an along-crystal fracture. The oil-quenched samples exhibit good room temperature plasticity due to the relatively low order degree and residual tensile stresses in the Fe-6.5wt.%Si alloy. Oil quenching improves the room temperature plasticity and cold rolling properties of Fe-6.5wt.%Si alloy warm rolled sheets, reduces edge cracks, and offers greater room temperature cold rolling processibility of the Fe-6.5wt.%Si alloy warm rolled sheets.

Genome-wide investigation of Cytochrome P450 superfamily of Aquilaria agallocha: Association with terpenoids and phenylpropanoids biosynthesis

Agarwood is a dark resinous wood, produced when Aquilaria tree responds to wounding and microbial infection resulting in the accumulation of fragrant metabolites. Sesquiterpenoids and 2-(2-phenylethyl) chromones are the major phytochemicals in agarwood and Cytochrome P450s (CYPs) are one of the important enzymes in the biosynthesis of these fragrant chemicals. Thus, understanding the repertoire of CYP superfamily in Aquilaria can not only give insights into the fundamentals of agarwood formation, but can also provide a tool for the overproduction of the aroma chemicals. Therefore, current study was designed to investigate CYPs of an agarwood producing plant, Aquilaria agallocha. We identified 136 CYP genes from A. agallocha genome (AaCYPs) and classified them into 8 clans and 38 families. The promoter regions had stress and hormone-related cis-regulatory elements which indicate their participation in the stress response. Duplication and synteny analysis revealed segmental and tandem duplicated and evolutionary related CYP members in other plants. Potential members involved in the biosynthesis of sesquiterpenoids and phenylpropanoids were identified and found to be upregulated in methyl jasmonate-induced callus and infected Aquilaria trees by real-time quantitative PCR analyses. This study highlights the possible involvement of AaCYPs in agarwood resin development and their complex regulation during stress exposure.

A novel univariate dimension‐reduction based interval finite element method for static response prediction of uncertain structures

AbstractTo eliminate the errors caused by the conventional interval perturbation finite element method due to classic interval arithmetic and neglect of higher‐order terms, we propose a novel univariate dimension‐reduction based interval finite element method to predict the static response bounds of structures with uncertain but bounded parameters. First, a univariate dimension‐reduction algorithm is derived using the generalized Taylor expansion. The global stiffness matrix is expressed as the sum of the median and the univariate disturbance radius. Compared with Taylor expansion approximation, the univariate dimension‐reduction approximation has higher accuracy and does not increase the amount of calculation. Then the inverse of the interval global stiffness matrix is approximated as an improved Neumann series. Higher‐ order terms are included by summing up the geometric terms in the Neumann series. Finally, the improved interval algorithm is used to solve the upper and lower bounds of the structural displacement response and the element stress response. The dependence between the interval parameters is accounted in comparison with the classic interval algorithm. The accuracy and effectiveness of the new method are validated by numerical cases on 2D truss, 3D frame and truck frame with multiple interval parameters.

Standardized RC beam tests for modeling the fiber bridging effect in SFRC

Fiber reinforcement is a promising solution to cracking problems and improving the concrete’s structural performance. The residual strength of the cracked concrete can characterize the reinforcement efficiency. However, quantifying the residual performance of steel fiber-reinforced concrete (SFRC) is challenging. The existing methodologies provide empirical formulas for estimating the residual strength using test results of SFRC elements in which a predominant crack governs the mechanical resistance. For instance, the 0.5 mm crack width determines the minimum value considered in the RILEM standard formulas. Thus, the SFRC strength evolution at earlier cracking stages remains unknown. At the same time, such a crack approximation is irrelevant to structural cases when reinforcement bars stimulate the formation of multiple cracks, and the 0.1–0.2 mm crack typically corresponds to the yielding of the steel bars. This study describes an alternative approach for quantifying the average residual stresses in SFRC elements with multiple cracks. It hypothesizes the possibility of separating the mechanical resistance components, corresponding to tension stiffening and fiber bridging effects characteristic of SFRC elements with bar reinforcement, using standardized small-scale specimens to estimate the fiber contribution. The laboratory tests of the plain concrete and SFRC beams with bar reinforcement illustrate the proposed technique. The Rilem standard three-point bending tests and the numerical simulation of full-scale beams verify the analysis’s adequacy. The developed model is suitable for finite element simulations (employing the smeared crack model); the capability of separating the tension stiffening and fiber bridging effects ensures its versatility.

Hardened Enhancement Investigation of Al-Zr-N Coating by EBM Technique: A review

The purpose of this research is to examine the Al-Zr-N coating applied to the E19 steel alloy by physical vapour deposition using an electron beam. The physical vapour deposition processes used to create layered [Al-Zr-N] coatings and the structures, wear resistances, and corrosion behaviours of these materials. In order to examine the coating structures, surface roughness, micro-hardness, micro-abrasion, and pin on disc were used. One of the residual stress elements that can lead to failure mechanisms for suitable coatings is thermal stress. The mechanical characteristics of the coating, including its deposition temperature, young's modulus, thermal expansion coefficient, and substrate and coating thickness, were investigated using a validated computational simulation in this paper.

Genome-Wide Identification and Expression Analysis of HSP70 Gene Family in Chrysanthemum lavandulifolium under Heat Stress

As a molecular chaperone, HSP70 is widely involved in complex activities in plants. Under high temperature, drought, high salt, low temperature, heavy metals, and other stresses, HSP70 is rapidly synthesizes, stabilizes protein and biological macromolecular structures, and improves the stress resistance of plants. In this study, 83 ClHSP70 genes in Chrysanthemum lavandulifolium were identified based on the published Chrysanthemum lavandulifolium genome database. The genes were divided into six clusters based on a phylogenetic analysis, and the gene structures, conserved motifs, and functional domains were relatively conserved. Only two collinear genes were observed, and they formed a pair of duplicating genes. Multiple abiotic stress and phytohormone response elements were observed on the ClHSP70 promoter, such as temperature, drought, methyl jasmonate, abscisic acid, and other stress-related elements, and CpG islands were found on some ClHSP70 promoters, suggesting that they may be related to methylation modifications. Tissue expression analysis showed that the ClHSP70 genes were highly expressed in the roots. In addition, the gene expression changed significantly after 1 h of heat treatment and plays an important role in plant responses to temperature stress. The results of this study provide insights on the ClHSP70 gene family members and a theoretical basis for further research on functional analyses of the ClHSP70 gene family.

Potential of Microalgae as Functional Foods Applied to Mitochondria Protection and Healthy Aging Promotion

The rapid aging of the Western countries’ populations makes increasingly necessary the promotion of healthy lifestyles in order to prevent/delay the onset of age-related diseases. The use of functional foods can significantly help to achieve this aim, thanks to the contribution of biologically active compounds suitable to protect cellular and metabolic homeostasis from damage caused by stress factors. Indeed, the excessive production of reactive oxygen species (ROS), favored by incorrect eating and behavioral habits, are considered causal elements of oxidative stress, which in turn favors tissue and organism aging. Microalgae represent a convenient and suitable functional food because of their extraordinary ability to concentrate various active compounds, comprising omega-3 polyunsaturated fatty acids, sterols, phenolic compounds, carotenoids and others. Within cells, mitochondria are the cellular organelles most affected by the accumulation of molecular damage produced by oxidative stress. Since, in addition to producing the chemical energy for cellular metabolism, mitochondria control numerous cell cycle regulation processes, including intrinsic apoptosis, responses to inflammatory signals and other biochemical pathways, their dysfunction is considered decisive for many pathologies. Among these, some degenerative diseases of the nervous system, cardiovascular system, kidney function and even cancer are found. From this viewpoint, bioactive compounds of microalgae, in addition to possessing high antioxidant properties, can enhance mitochondrial functionality by modulating the expression of numerous protective factors and enzymes, which in turn regulate some essential biochemical pathways for the preservation of the functional integrity of the cell. Here, we summarize the current knowledge on the role played by microalgal compounds in the regulation of the mitochondrial life cycle, expression of protective and reparative enzymes, regulation of intrinsic apoptosis and modulation of some key biochemical pathways. Special attention was paid to the composition of some cultivable microalgae strains selected for their high content of active compounds suitable to protect and improve mitochondrial functions.

Mesh‐size independent rigid‐body spring network for simulation of the dynamic fracture behavior of concrete

AbstractIn this study, a numerical approach is developed for simulating the rate‐dependent behaviors of concrete without mesh sensitivity. The rheological units (e.g., dashpot) are integrated with the six directional springs in the rigid‐body spring network (RBSN) elements to reflect the rate‐dependent behavior of concrete. Previously, the viscoplastic damage model was associated with the elemental degrees of freedom. However, in the present approach, a viscoelastic constitutive law is newly defined for the normal direction as a function of the strain rate, from which the internal forces can be updated from the regularized elemental stresses. Such improvements are validated through the numerical simulations of the direct tensile test and spalling test using the modified split‐Hopkinson pressure bar (SHPB). The simulated results show consistent structural responses without mesh dependence on the strain rate. In addition, the influences of the softening curve shapes on the crack localizations are examined. It is shown that the rheological parameters can be optimized and determined for consistent applications through virtual experiments. The proposed numerical approach enables the mesh construction procedure without concerning the mesh‐size sensitivity due to the strain rate, and various applications are expected for the simulations of detailed numerical models of concrete materials and structures under high loading rates.

INSTRUMENT FOR MEASURING PULSATION CHARACTERISTICS IN TURBULENT FLOWS

The paper considers the design of a two-component strain gauge construction for measuring pulsation characteristics in turbulent flows.&#x0D; The analysis is carried out and the shortcomings of the existing sensor models and their influence on the reliability and accuracy of the experimental results are shown. The limited frequency range of such sensors is also emphasized.&#x0D; The design of the previous types of sensors is based on a plate on which wire or film strain gauges are glued. In such models, the main part of the perceiving hydrodynamic pressure goes to the formation of stresses in the elastic plate, and only a small part (up to 4%) - to create stresses in the strain-sensitive elements. Such sensors require an increase in the size of sensitive elements, this causes an additional disturbance in the flow, which in turn also reduces the accuracy of the measurement.&#x0D; The use of glue in the design of the sensor is associated with adverse effects such as creep and aging of the glue.&#x0D; The proposed sensor used strain gauges in the form of constantan wires stretched parallel to each other, which helped to get rid of elastic plates and glue, and also reduced the size of the sensing element.&#x0D; A construction of the sensor is shown and its design is described.&#x0D; The sensor has a free vibration frequency in water of more than 300 Hz, which is more than an order of magnitude higher than the frequency of water flow oscillations. This allows a more accurate measurement of pulsation characteristics.&#x0D; The principle of operation of the strain gauge is considered.&#x0D; The presence in the construction of four correspondingly located tensile strands made it possible to measure the longitudinal and transverse components of the pulsation velocities in turbulent flows.

Study on hybrid stress element of three-dimensional arbitrary polyhedron

In three-dimensional problems, regular tetrahedron, pentahedron, and hexahedron elements are used in standard finite element software. In practice, however, the three-dimensional model is irregular. Traditional regular elements cannot accurately describe model structure. The field function integral accuracy of traditional displacement finite elements is low, and the number of elements considerably affects the integral results. As the number of elements increases, the computational efficiency decreases as well. Therefore, based on the hybrid stress element method, this paper proposes a new numerical calculation element for three-dimensional problems–a three-dimensional arbitrary polyhedron element. The corresponding calculation scheme is the 3-Dimensional Voronoi Cell Finite Element Method (3DVCFEM). This paper first verifies the effectiveness of the scheme. The stress field model with a singular solution is further simulated, and the change rule of the number of stress terms is obtained. On this basis, 3DVCFEM is introduced into calculating octree elements to solve complex classification problems and difficult calculation of octree elements. Moreover, the efficiency of the octree elements is investigated.

Effect of Radionuclides and Trace Elements on Antioxidant System of Brown Seaweeds.

Ecological effects in marine living can be understood via the determination of antioxidant molecules in aquatic organisms against pollutants. This study aims to evaluate the radionuclides and trace element stress with response molecules. Cystoseira crinita and Halopteris scoparia have been chosen as study materials because of their susceptibility to pollution. The radionuclides 210Po, 238U, 232Th and 40K and trace elements Al, Fe, Mn, Cr, As, Zn and Pb levels were analysed as well as antioxidants and antioxidant enzymes in two brown algae, seasonally. Marine pollutants in terms of radionuclides and trace elements were correlated with antioxidant molecules in these species and may be used as biomarkers for assessing the radioactive stress. The 210Po and Mn concentrations in C. crinita seem to activate catalase (CAT) and superoxide dismutase (SOD) enzyme activities while 210Po concentrations inclined the proline amount in H. scoparia. This study demonstrated the radiation stress-induced the antioxidant defence system in macroalgae, the primary producers of the marine environment.

Characterization of the 1-Deoxy-D-xylulose 5-Phosphate synthase Genes in Toona ciliata Suggests Their Role in Insect Defense.

The first enzyme, 1-Deoxy-D-xylulose-5-phosphate synthase (DXS), in the 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway for isoprenoid precursor biosynthesis has been reported to function differently according to species. However, the current state of knowledge about this gene family in Toona ciliata is limited. The TcDXS gene family was identified from the whole genome of T. ciliata by firstly using bioinformatics analysis. Then, the phylogenetic tree was built and the promoter cis-elements were predicted. Six DXS genes were identified and divided into three groups, which had similar domains and gene structure. They are located on five different chromosomes and encode products that do not vary much in size. An analysis of the cis-acting elements revealed that TcDXS genes possessed light, abiotic stress, and hormone responsive elements. Ultimately, TcDXS1/2/5 was cloned for an in-depth analysis of their subcellular localization and expression patterns. The subcellular localization results of TcDXS1/2/5 showed that they were located in the chloroplast envelope membranes. Based on tissue-specific analyses, TcDXS1/2/5 had the highest expression in mature leaves. Under Hypsipyla robusta stress, their different expressions indicated that these genes may have insect-resistance functions. This research provides a theoretical basis for further functional verification of TcDXSs in the future, and a new concept for breeding pest-resistant T. ciliata.