Small auxin-up RNA gene OsSAUR33 promotes seed aging tolerance in rice

Seed aging tolerance during storage is generally an important trait for crop production, yet the role of small auxin-up RNA genes in conferring seed aging tolerance is largely unknown in rice. In this study, one small auxin-up RNA gene, OsSAUR33, was found to be involved in the regulation of seed aging tolerance in rice. The expression of OsSAUR33 was significantly induced in aged seeds compared with unaged seeds during the seed germination phase. Accordingly, the disruption of OsSAUR33 significantly reduced seed vigor compared to the wild type(WT) in response to natural storage or artificial aging treatments. The rice OsSAUR33 gene promotes the vigor of aged seeds by enhancing their reactive oxygen species(ROS) level during seed germination, and the accumulation of ROS was significantly delayed in the aged seeds of Ossaur33 mutants in comparison with WT during seed germination. Hydrogen peroxide(H_(2)O_(2)) treatments promoted the vigor of aged seeds in various rice varieties. Our results provide timely theoretical and technical insights for the trait improvement of seed aging tolerance in rice.

Influence of Trace Oxygen on the Mechanical Properties of High Pure Silver during Natural Aging

Two kinds of high pure silver materials with 5.3 ppm oxygen and 32.7 ppm oxygen were prepared by various melting processes, both samples were subjected to accumulative rolling with 95% thickness reduction. Their mechanical properties were tested during long natural aging. Results showed that the Ag sheet with 5.3 ppm oxygen is at full annealed state when natural aging 58 days or kept at 150℃ for 30 minutes, and the Ag sheet with 32.7 ppm oxygen is a little of recovery when natural aging a year. It is suggested that appropriate oxygen interstitial solute in Ag solid solution and a few of Ag2O particles at Ag grain boundaries impede the recovery and recrystallization of Ag sheets.

Regulation of Nitric Oxide on the Aging Process of Wheat Leaves

When the first fully expanded leaf of wheat ( Triticum aestivum L.) seedlings with two leaves were treated with different concentrations (0.05, 0.10, 0.20 and 0.50 mmol/L) of nitric oxide donor, sodium nitroprusside (SNP), the contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA) were reduced by the lower concentrations (0.05, 0.10 and 0.20 mmol/L), but enhanced by the higher concentration of SNP (0.50 mmol/L). The protective effect of 0.10 mmol/L SNP was the most obvious. Furthermore, the treatment with 0.10 mmol/L SNP on the above seedlings until the fourth leaves were fully expanded attenuated the accumulation of H2O2, superoxide anion radical (O-2(-)) and MDA, also counteracted the degradation of chlorophyll and soluble proteins, especally Rubisco, both leading to the effective delay of aging process in wheat leaves. The effects of different SNP concentrations (0.05, 0.10, 0.20, 0.50, 1.00 and 5.00 mmol/L) also displayed a dual role in an aging experiment of chloroplasts in vitro, one of which, 0.2 mmol/L SNP treatment, protected the membrane structure and attenuated the degradation of Rubisco effectively. Based on the present results, it was inferred that lower concentrations of nitric oxide (NO) might play a role in delaying aging process in wheat leaves, i.e., might attribute to decrease the level of reactive oxygen species (ROS) and the alleviation of further oxidative damage caused by ROS.

Mitochondria and the aging heart

The average human life span has markedly increased in modem society largely attributed to advances in medical and therapeutic sciences that have successfully reduced important health risks. However, advanced age results in numerous alterations to cellular and subcellular components that can impact the overall health and function of an individual. Not surprisingly, advanced age is a major risk factor for the development of heart disease in which elderly populations observe increased morbidity and mortality. Even healthy individuals that appear to have normal heart function under resting conditions, actually have an increased susceptibility and vulnerability to stress. This is confounded by the impact that stress and disease can have over time to both the heart and vessels. Although, there is a rapidly growing body of literature investigating the effects of aging on the heart and how age-related alterations affect cardiac function, the biology of aging and underlying mechanisms remain unclear. In this review, we summarize effects of aging on the heart and discuss potential theories of cellular aging with special emphasis on mitoehondrial dysfunction.

Light-induced ZnO/Ag/rGO bactericidal photocatalyst with synergistic effect of sustained release of silver ions and enhanced reactive oxygen species

Silver nanoparticles (Ag NPs) can effectively address the issue of antibiotic-resistant bacterial infections to reduce the potential toxicity of Ag NPs. Although challenging, it is, therefore, necessary to achieve the sustainable release of Ag+ ions from a finite amount of Ag NPs. This study aims at designing an efficient and benign antimicrobial silver-based ternary composite composed of photocatalysis zinc oxide (ZnO) and reduced graphene oxide (rGO) as a carrier, in which the reactive oxygen species (ROS) excited from ZnO and Ag+ ions released from the Ag NPs cooperate to realize an effective antibacterial activity against E. coli and S. aureus. The constant effective bacterial performance of the ternary photocatalyst with minimum Ag content can be attributed to the increase in the available quantity of ROS, which results from the enhanced separation efficiency of the photogenerated carriers. The proposed system notably realized the long-term sustainable release of Ag+ ions with low concentration for 30 days when compared with an equivalent amount of silver nitrate. Moreover, the use of the composite prevents biotoxicity and silver wastage, and imparts enhanced stability to the long-lasting antibacterial efficacy.

Aging:A mitochondrial DNA perspective,critical analysis and an update

The mitochondrial theory of aging, a mainstream theory of aging which once included accumulation of mitochondrial DNA(mt DNA) damage by reactive oxygen species(ROS) as its cornerstone, has been increasingly losing ground and is undergoing extensive revision due to its inability to explain a growing body of emerging data. Concurrently, the notion of the central role for mtDNA in the aging process is being met with increased skepticism. Our progress in understanding the processes of mtDNA maintenance, repair, damage, and degradation in response to damage has largely refuted the view of mt DNA as being particularly susceptible to ROS-mediated mutagenesis due to its lack of "protective" histones and reduced complement of available DNA repair pathways. Recent research on mitochondrial ROS production has led to the appreciation that mitochondria, even in vitro, produce much less ROS than previously thought, automatically leading to a decreased expectation of physiologically achievable levels of mtDNA damage. New evidence suggests that both experimentally induced oxidative stress and radiation therapy result in very low levels of mtDNA mutagenesis. Recent advances provide evidence against the existence of the "vicious" cycle of mtDNA damage and ROS production. Meta-studies reveal no longevity benefit of increased antioxidant defenses. Simultaneously, exciting new observations from both comparative biology and experimental systems indicate that increased ROS production and oxidative damage to cellular macromolecules, including mtDNA, can be associated with extended longevity. A novel paradigm suggests that increased ROS production in aging may be the result of adaptive signaling rather than a detrimental byproduct of normal respiration that drives aging. Here, we review issues pertaining to the role of mtDNA in aging.

VARIATION OF SUBSTRUCTURES OF PEARLITIC HEAT RESISTANT STEEL AFTER HIGH TEMPERATURE AGING

The observations of dislocations, substructures and other microstructural details were conducted mainly by means of transmission electron microscope (TEM) and scanning electron microscope (SEM) for 12CrlMoV pearlitic heat-resistant steel. It is shown that during the high temperature long-term aging, the disordered and jumbled phase-transformed dislocations caused by normalized cooling are recovered and rearranged into cell substructures, and then the dislocation density is reduced gradually. Finally a low density linear dislocation configuration and a stabler dislocation network are formed and ferritic grains grow considerably.

Gas-phase epoxidation of propylene by molecular oxygen over Ag-Cu-Cl/BaCO_3 catalyst:Effects of Cu and Cl loadings

Ag‐Cu‐Cl/BaCO3 catalysts with different Cl and Cu loadings, prepared by the reduction deposition impregnation method, were investigated for gas‐phase epoxidation of propylene by molecular oxygen and characterized by X‐ray diffraction, X‐ray photoelectron spectroscopy and O2 temperatureprogrammed desorption. Ag‐Cu‐Cl/BaCO3 catalyst with 0.036 wt% Cu and 0.060 wt% Cl exhibitedthe highest catalytic performance for gas‐phase epoxidation of propylene by molecular oxygen. Apropylene oxide selectivity of 83.7% and propylene conversion of 1.2% were achieved under thereaction conditions of 20% C3H6‐10% O2‐70% N2, 200 °C, 0.1 MPa and 3000 h?1. Increasing the Clloading allowed Ag to ensemble easier, whereas changing the Cu loading showed little effect on Agcrystallite size. The appropriate Cl loading of Ag‐Cu‐Cl/BaCO3 catalyst can reduce the dissociationadsorption of oxygen to atomic oxygen species leading to the combustion of propylene to CO2, whichbenefits epoxidation of propylene by molecular oxygen. Excessive Cl loading of Ag‐Cu‐Cl/BaCO3catalyst decreases propylene conversion and propylene oxide selectivity remarkably because of Clpoisoning. The appropriate Cu loading of Ag‐Cu‐Cl/BaCO3 catalyst is efficient for the epoxidation ofpropylene by molecular oxygen, and an excess Cu loading decreases propylene oxide selectivitybecause the aggregation of Cu species increases the exposed surfaces of Ag nanoparticles, whichwas shown by slight increases in atomic oxygen species adsorbed. The appropriate loadings of Cu and Cl of Ag‐Cu‐Cl/BaCO3 catalyst are important to strike the balance between molecular oxygen and atomic oxygen species to create a favorable epoxidation of propylene by molecular oxygen.

Functional magnetic resonance imaging and the brain: A brief review

Functional magnetic resonance imaging(fMRI) is em-ployed in many behavior analysis studies, with blood oxygen level dependent-(BOLD-) contrast imaging being the main method used to generate images. The use of BOLD-contrast imaging in f MRI has been refined over the years, for example, the inclusion of a spin echo pulse and increased magnetic strength were shown to produce better recorded images. Taking careful precautions to control variables during measurement, comparisons between different specimen groups can be illustrated by f MRI imaging using both quantitative and qualitative methods. Differences have been observed in comparisons of active and resting, developing and aging, and defective and damaged brains in various studies. However, cognitive studies using f MRI still face a number of challenges in interpretation that can only be overcome by imaging large numbers of samples. Furthermore, f MRI studies of brain cancer, lesions and other brain pathologies of both humans and animals are still to be explored.

Mitochondrial redox metabolism in aging:Effect of exercise interventions

Mitochondrial redox metabolism has long been recognized as being central to the effects of aging and the development of age-related pathologies in the major oxidative organs. Consistent evidence has shown that exercise is able to retard the onset and impede the progression of aging by modifying mitochondrial oxidant--antioxidant homeostasis. Here we provide a broad overview of the research evidence showing the relationship between mitochondrial redox metabolism, aging and exercise. We address part aspects of mitochondrial reactive oxygen species （ROS） metabolism, from superoxide production to ROS detoxification, especially antioxidant enzymes and uncoupling protein. Furthermore, we describe mitochondrial remodeling response to aging and exercise, which is accompanied by bioenergetics and redox regulation. In addition, potential mechanisms for redox signaling involved in mitochondrial remodeling and redox metabolism regulation are also reviewed.

Molecular mechanisms of cardiac aging

Age-associated changes in cardiovascular structure/ function are implicated in the markedly increased risk for cardiovascular disease in older persons. Aging not only prolongs exposure to several other cardiovascular risks, but also leads to intrinsic cardiac changes, which reduces cardiac functional reserve, predisposes the heart to stress and contributes to increased cardiovascular mortality in the elderly. Intrinsic cardiac aging in the murine model closely recapitulates age-related cardiac changes in humans, includ- ing left ventricular hypertrophy, fibrosis and diastolic dysfunction. Cardiac aging in mice is accompanied by accumulation of mitochondrial protein oxidation, increased mitochondrial DNA mutations, increased mitochondrial biogenesis, as well as decreased cardiac SERCA2 protein. All of these age-related changes are significantly attenu- ated in mice overexpressing catalase targeted to mitochondria （mCAT）. These findings demonstrate the critical role of rnitochondrial reactive oxygen species （ROS） in cardiac ag ing and support the potential antioxidants to cardiac aging lar diseases. application of mitochondrial and age-related cardiovascular diseases.

锌电积用Pb-Ag阳极MnO_(2)镀膜的电化学性能

锌电积用Pb-Ag阳极存在析氧过电位高、表面铅易电化学氧化溶解,造成阴极电锌品质低等突出问题,如何减少阳极的溶铅污染并提升其催化析氧活性、降低反应能耗,成为亟待解决的难题。本文在Pb-Ag阳极表面电沉积一层均匀、致密的MnO_(2)薄膜,采用SEM、XRD和ICP等对MnO_(2)催化层的表面微观形貌、晶体结构和溶液含铅量进行分析;采用CV、LSV、EIS和Tafel等对Pb-Ag/MnO_(2)阳极的析氧催化活性和耐腐蚀性能进行分析。结果表明:在MnSO_(4)-H_(2)SO_(4)溶液中,当循环速率为200 mL/min、温度为80℃时,以4 mA/cm^(2)电沉积120 min制备的Pb-Ag/MnO_(2)镀膜电极具有最佳的催化析氧和耐蚀性能;PbAg阳极经优化镀膜后,50 mA/cm^(2)时其析氧过电位由936 mV降低为648 mV,腐蚀电流密度由7.03μA/cm^(2)降低至0.66μA/cm^(2);相较于Pb-Ag阳极,基于Pb-Ag/MnO_(2)阳极的15 d长周期电锌体系中溶铅量由0.61 mg/L降至0.29 mg/L。

Review of Major Theories of Skin Aging

Here we aim to describe each factor that leads to skin aging and describe their mechanisms. A PubMed database searches (from January 2004 to March 2014) using aging and skin as searched terms. There are substantial evidences showing that aging is associated with damage from free radicals represented by various reactive oxygen species (ROS). Mitochondria are producers and also targets of oxidative stress. The cycle of mitochondrial dysfunction can trigger the aging process. In the cellular senescence and telomeres theory, the diploid cells exhibit a limited proliferation potential. After a finite number of divisions, they enter a state of senescence with a stop replication in cell proliferation. It is suggested that aging is associated mainly with hyper-regulation of apoptosis. Obesity presumably accelerates the process of aging, which is aggravated by smoking. And the influence of the environment, called solar UV irradiation is of considerable importance to skin aging. There are several mechanisms that trigger the natural aging process and contribute to age-related changes, including oxidative stress theory of free radicals, the mitochondrial dysfunction, telomere shortening, UV radiation and other mechanisms that taken together or alone may or not accelerate the change in skin.

One-pot synthesis of Ag-rich AgPd alloy nanoactiniae and their enhanced electrocatalytic activity toward oxygen reduction

The electro-catalytic properties can be effectively optimized by designing bimetallic alloy nanoparticles with high-content less-active metal to enhance the competence of more-active noble metal. Herein, a one-pot hydrothermal approach is demonstrated for the controllable synthesis of Ag-rich Ag_9Pd_1 alloy nanoactiniae with obviously enhanced electro-catalytic activity(2.23 mA cm^(-2) at 0.85 V) and stability for oxygen reduction reaction. In alkaline solution, the ORR onset potential and half-wave potential of the Ag_9Pd_1 alloy nanoactiniae can reach a value of 1.02 V and 0.89 V, respectively, which origin from strong ligand and ensemble effects between Pd element and Ag element. The nanocrystals are uniformly alloyed, displaying a Ag_9Pd_1 combination, as displayed by an assembly of X-ray diffraction(XRD) spectrum,energy dispersive X-ray(EDX) analysis, and cyclic voltammetry(CV). This concept of tuning bimetallic alloy nanocrystals with low concentrations of more precious metal may be a promising approach to be applicable to a wide range of alloy nanocrystals.

Mechanical and Electrical Properties of Y-containing Al-Zr Heat-resistant Alloy Produced by Dynamic ECAE Process

The influence of rare earth Y on the microstructure and mechanical properties of Al-Zr alloy produced by dynamic ECAE was studied by OLYMPUS-BX51M optical microscope(OM),S4800 energy disperse spectroscopy(EDS)and SANS CMT5105 electronic universal material testing machine,and the corresponding equivalent conductivity was also investigated by using QJ48 DC electric bridge.The results show that the tensile strength of Al-Zr conductor first increases and then decreases with the increase of the aging time and temperature,and the highest tensile value can be obtained under the aging temperature of 160°C for 4 h.The ductility and the resistivity of the Al-Zr alloy have inverse proportion to the aging time.The rare earth Y has significantly improved the electrical and mechanical properties of Al-0.3%Zr heat-resistant alloy.In this study,the tensile strength and the elongation of the Al-0.3%Zr-0.2%Y alloy,after aging treatment at 220°C for 14 h,are about 278.49 MPa and 6.7%,respectively,and the equivalent conductivity is about 59.6 IACS.Hence the synthetical properties of the Y-containing alloy are significantly improved compared with traditional Al-0.3%Zr alloy.

Ag2-xO with highly exposed{111}crystal facets for efficient electrochemical oxygen evolution:Activity and mechanism

A series of Ag2–xO/FTO-i electrodes(where i denotes the current density during the electrodeposition, and i = 0.5, 1, 2, 3, 4, or 7) was fabricated in 0.1 M K2B4O7 electrolyte containing Ag+ ions by galvanostatic electrocrystallization. The electrode composition and morphology were characterized using X-ray powder diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The results reveal that the electrode films consist of Ag2O, but some of the Ag+ ions on the {111} crystal facets are oxidized into Ag2+ ions. Furthermore, the Ag2–xO/FTO-1 electrode shows a triangular slice shape of a parallel matrix with a larger exposed area of {111} crystal facets than other Ag2–xO/FTO-i(i = 0.5, 2, 3, 4, or 7) electrodes. Electrocatalytic experiments prove that the Ag2–xO/FTO-1 electrode produces the highest oxidative current density, has an overpotential of 417 m V at 10 m A cm–2, and has a Tafel slope of 47 m V dec–1 in 0.1 M K2B4O7. Electrochemical impedance spectra indicate that Ag2–xO/FTO-1 electrodes have the best ability for charge transfer. In addition, in the I-t test over 10 h, the current density decreased 4%. Fortunately, both O–O and Ag2+ species were detected after electrocatalysis and a possible mechanism for the oxygen evolution reaction is proposed in which the formation of Ag2+ and O–O species on {111} facets plays a critical role.

Antioxidant mechanism of modified Qiongyu paste against aging based on network pharmacology and experimental validation

Objective:To provide a possible basis for the anti-aging effect of modified Qiongyu paste(MQP).Methods:Ultra-high-performance liquid chromatography-Q-Orbitrap mass spectrometry was applied to confirm the effective components of MQP that we had identified from databases and research literature.Then,network pharmacology was employed to predict the possible underlying mechanism of MQP against aging.According to the overlap with age-related gene targets,we obtained key targets of MQP against aging using protein-protein interaction analyses.Superoxide dismutase(SOD)tests were performed in vitro and in vivo.Western blotting of P62 and LC3B and quantitative polymerase chain reaction of the expression of the P62,LC3B,HO-1,Keap1,and Nrf2 genes were conducted on H_(2)O_(2) -induced PC12 cells.Enzyme-linked immunosorbent assays of tumor necrosis factor-a and interleukin-6 were conducted on a D-galactose-induced aging mice model.Results:A total of 44 compounds in MQP were finally identified,and 48 gene targets were considered related to anti-aging.Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment analyses linked the principal anti-aging mechanisms of MQP to oxidative resistance,genomic stabilization,and growth hormone regulation.In vitro,H_(2)O_(2)-induced PC12 cells showed that MQP was able to activate SOD,prolong telomeres,and enhance the expression levels of P62,LC3B,HO-1,Keap1,and Nrf2.The quantitative polymerase chain reaction results were affirmed with the reactive oxygen species inhibitor N-acetylcysteine and the reactive oxygen species agonist diallyl-tetrasulfide.In vivo,the D-gal-induced aging mice showed that MQP increased SOD in the brain and reduced tumor necrosis factor-α and interleukin-6 in the serum.Thus,our results suggest that the mechanism of the anti-aging effect of MQP primarily involves antagonizing oxidative stress.Conclusion:From the analyses and experimental validation,we may conclude that oxidative stress resistance may be a potential mechanism of the MQP anti-aging effect.

电积锌用Pb-Ag/MnO_(2)涂层阳极制备及电化学性能

铅银合金(Pb-Ag)是锌电积及其它冶金工艺中应用最广泛的阳极材料。随着节能环保要求的逐渐提高,由于存在过电位低和稳定性差等缺点,Pb-Ag阳极难以适用于绿色工业体系的发展。如何提升其析氧催化活性、降低能耗并提高其耐腐蚀性能,成为亟待解决的工业难题。采用恒电流电沉积法在Pb-Ag阳极上制备了纳米二氧化锰薄膜涂层,测试了阳极的组织和电化学性能。研究表明:MnO_(2)涂层表面疏松裂纹结构不仅提高了催化活性,还促进了传质过程的进行,使得Pb-Ag/MnO_(2)阳极的析氧反应活性和稳定性均优于Pb-Ag阳极。其中,Pb-Ag/MnO_(2)阳极的析氧过电位为555 mV,塔菲尔斜率为208.5 mV/dec,优于Pb-Ag阳极的析氧过电位和塔菲尔斜率。同时,Pb-Ag/MnO_(2)阳极在长周期的电解锌实验中表现出良好的析氧反应活性和耐腐蚀性能,其槽电压比Pb-Ag阳极槽电压小0.1 V左右,能耗低于Pb-Ag阳极。

Ground-based investigation of atomic oxygen effects on naked Ag and Ag with protective organic coatings

Protective behavior of organic coatings of alkyd, epoxy, urethane and siloxane applied to silver solar cell interconnects and erosion of Ag were investigated by exposure experiments to ground simulation atomic oxygen (AO). Evaluations of their protective properties were made through assessing their mass change characteristics, chemical and physical changes to AO attack. The specimens after exposure were analyzed with SEM/EDAX and XPS. The results indicated that the silver is heavily etched, some coatings such as epoxy, alkyd, urethane are seriously degraded or removed as volatile oxides and the morphology of coatings changed. It is evident that siloxane coatings have excellent properties for anti-AO attack. The erosion product consists of silicon dioxide layer of compact texture and is left on the surface to provide adequate protection from further attack by the energetic AO.

SEA SURFACE SALINITY AND BOTTOM WATER OXYGENATED CONDITIONS IN WESTERN EQUATORIAL PACIFIC MARGINAL SEAS DURING THE LAST GLACLAL AGE

Based on Core GGC-6 from the South China Sea (SCS) and Core GGC-29 from the Sulu Sea,planktonic and benthic foraminifera and organic carbon measurements were used to evaluate the Water mass conditions in these sea areas during the last glacial age. The results show that the higher organic carbon contents in the SCS and Sulu Sea during the last glacial period were mainly caused by low dissolved oxygen concentrations in bottom waters and that in the last glacial to Holocene, the fluctuation of dissolvd oxygen in the bottom weters was large in the SCS and reatively stable in the Sulu Sea. In addition, increased precipitation reduced surface water salinities, which at the water column to be more stratified in the SCS and Sulu Sea during the last glacial period. This process lowered dissolved oxygen concentrations in bottom waters, which resulted in better preservation of organic matter in both basins.