By numerically solving the two-dimensional time-dependent Schr¨odinger equation under the frozen-nuclei approximation, we are able to study the molecular photoelectron-momentum distribution(MPMD) of H^+_2 with di...By numerically solving the two-dimensional time-dependent Schr¨odinger equation under the frozen-nuclei approximation, we are able to study the molecular photoelectron-momentum distribution(MPMD) of H^+_2 with different orientation angles driven by elliptically polarized laser pulse with varying ellipticities. Our numerical results show that the MPMD is sensitive to the orientation angle and the laser ellipticity, which can be explained by the attosecond perturbation ionization theory and the exactly solvable photoionization model. When the ellipticity ε = 0, the final MPMD of x-oriented H^+_2 shows a distinct six-lobe pattern that is different from that with ε = 0.5 and ε = 1. The evolutions of electron wave packet(EWP)and MPMD with x-oriented H^+_2 are presented to interpret this distinct pattern.展开更多
First-principles calculations are performed to investigate the relaxation and electronic properties of sulfide minerals surfaces(MoS2, Sb2S3, Cu2 S, ZnS, PbS and FeS2) in presence of H2 O molecule. The calculated resu...First-principles calculations are performed to investigate the relaxation and electronic properties of sulfide minerals surfaces(MoS2, Sb2S3, Cu2 S, ZnS, PbS and FeS2) in presence of H2 O molecule. The calculated results show that the structure and electronic properties of sulfide minerals surfaces have been influenced in presence of H2 O molecule. The adsorption of the flotation reagent at the interface of mineral-water would be different from that of mineral surface due to the changes of surface structures and electronic properties caused by H2 O molecule. Hence, the influence of H2 O molecule on the reaction of flotation reagent with sulfide mineral surface will attract more attention.展开更多
In this study,the benign target double terpyridine parts based amphiphilic ionic molecules(AIMs 1,2)and the reference single terpyridine segment included AIMs(AIMs 3,4)were synthesized through a multi-step method,and ...In this study,the benign target double terpyridine parts based amphiphilic ionic molecules(AIMs 1,2)and the reference single terpyridine segment included AIMs(AIMs 3,4)were synthesized through a multi-step method,and the molecular structures were fully characterized.The excellent anticorrosion of the target AIMs for copper surface in H_(2)SO_(4) solution was demonstrated by the electrochemistry analysis,which was more superior over those of the reference AIMs.The standard adsorption free energy changes of the target AIMs calculated by the adsorption isotherms were lower than -40 kJ·mol^(-1),suggesting an intensified chemical adsorption on metal surface.The molecular modeling and molecular dynamic computation of the studied AIMs were performed,demonstrating that the target AIMs exhibited lower highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps and greater adsorption energies than the reference ones.The chemical adsorption of the AIMs on metal surface was revealed by various spectroscopic methods including scanning electron microscopy,atomic force microscopy,Fourier transform infrared spectroscopy,attenuated total reflection infrared spectroscopy,Raman and X-ray diffraction.展开更多
Lattice defects induced by ion implantation into SiC have been widely investigated in the decades by various techniques.One of the non-destructive techniques suitable to study the lattice defects in SiC is the optical...Lattice defects induced by ion implantation into SiC have been widely investigated in the decades by various techniques.One of the non-destructive techniques suitable to study the lattice defects in SiC is the optical characterization.In this work,confocal Raman scattering spectroscopy and photoluminescence spectrum have been used to study the effects of 134-keV H_(2)^(+)implantation and thermal treatment in the microstructure of 6H-SiC single crystal.The radiation-induced changes in the microstructure were assessed by integrating Raman-scattering peaks intensity and considering the asymmetry of Raman-scattering peaks.The integrated intensities of Raman scattering spectroscopy and photoluminescence spectrum decrease with increasing the fluence.The recovery of the optical intensities depends on the combination of the implantation temperature and the annealing temperature with the thermal treatment from 700℃to 1100℃.The different characterizations of Raman scattering spectroscopy and photoluminescence spectrum are compared and discussed in this study.展开更多
Ether-based electrolytes with relatively high stability are widely used in Li-O_(2) batteries (LOBs) with high energy density.However,they are still prone to be attacked by reactive oxygen species.Understanding the de...Ether-based electrolytes with relatively high stability are widely used in Li-O_(2) batteries (LOBs) with high energy density.However,they are still prone to be attacked by reactive oxygen species.Understanding the degradation chemistry of ether-based solvent induced by reactive oxygen species is significant importance toward selection of stable electrolytes for LOBs.Herein,we demonstrate that a great amount of H_(2) gas evolves on the Li anode during the long-term discharge process of LOBs,which is due to the electrolyte decomposition at the oxygen cathode.By coupling with in-situ and ex-situ characterization techniques,it is demonstrated that O_(2)^(-) induces the H-abstraction of tetraethylene glycol dimethyl ether(TEGDME) to produce a large amount of H_(2)O at cathode,and this H_(2)O migrates to Li anode and produce H_(2) gas.Based on the established experiments and spectra,a possible decomposition pathway of TEGDME caused by O_(2)^(-)at the discharge process is proposed.And moreover,three types of strategies are discussed to inhibit the decomposition of ether-based electrolytes,which should be highly important for the fundamental and technical advancement for LOBs.展开更多
Atomic sites co-catalyst (ASC) on photocatalytic materials possesses an attractive prospect to promote charge carrier separation and tune surface reaction kinetics,yet the synthesis of earth-abundant ASC under low tem...Atomic sites co-catalyst (ASC) on photocatalytic materials possesses an attractive prospect to promote charge carrier separation and tune surface reaction kinetics,yet the synthesis of earth-abundant ASC under low temperature remains a great challenge.Here,a novel in-situ NH_(4)^(+)-etched strategy to anchor atomic Mo sites on ZnIn_(2)S_(4)hierarchical nanotubes (HNTs) with abundant mesopores under mild conditions for promoting charge carrier separation and enhancing light multi-reflections is developed for efficient photocatalytic H_(2) evolution.Density functional theory calculations and linear sweep voltammetry demonstrate that the well-defined Mo-S_(2)O_(1) sites with distinctive coordination configuration and electronic property contribute to the enhanced separation of photo-generated charge carriers and reduced Gibbs free energy for H_(2) evolution.Consequently,the well-defined MoSA-ZIS HNTs present an excellent photocatalytic activity with a rate of 29.9μmol h^(-1)(5.98 mmol g^(-1)h^(-1)),which is 7.3 times higher than that of ZnIn_(2)S_(4)nanosheets (NSs),to be among the best ZnIn_(2)S_(4)-based photocatalysts.The present strategy breaks the high-temperature limitation of conventional top-down thermal dissociation/emitting approach for anchoring non-noble metal atomic sites on catalyst support.展开更多
Molybdenum trioxide(MoO_(3))can be employed as an excellent host for intercalation due to its 2D lay-ered structure that connected by van der Waals interactions.Herein,a series of polyoxometalate-based MoO_(3) composi...Molybdenum trioxide(MoO_(3))can be employed as an excellent host for intercalation due to its 2D lay-ered structure that connected by van der Waals interactions.Herein,a series of polyoxometalate-based MoO_(3) composites(Al_(13)@MoO_(3))were successfully prepared by interpolating the Keggin-type polycationic AlO_(4)Al_(12)(OH)_(24)H_(2)O_(12)^(7+)(Al_(13))into MoO_(3)gallery.These composites can be applied to rapidly adsorb the anionic dye methyl orange(MO)through strong electrostatic interactions lead to compact and sta-ble gathering in the surrounding of the numerous charged Al_(13).Adsorption behaviors of composites with the different amount of Al_(13) were determined,these results revealed that Al_(13)-3.34%@MoO_(3)exhibited the most remarkable adsorption capacity.More importantly,the composite maintains superior adsorption capacity for five consecutive adsorption/desorption cycles,suggesting that Al_(13)@MoO_(3)can be an efficient and durable adsorbent.展开更多
A long wavelength emission fluorescent(612 nm)chemosensor with high selectivity for H_(2)PO_(4)^(−)ions was designed and synthesized according to the excited state intramolecular proton transfer(ESIPT).The sensor can ...A long wavelength emission fluorescent(612 nm)chemosensor with high selectivity for H_(2)PO_(4)^(−)ions was designed and synthesized according to the excited state intramolecular proton transfer(ESIPT).The sensor can exist in two tautomeric forms(‘keto’and‘enol’)in the presence of Fe^(3+)ion,Fe^(3+)may bind with the‘keto’form of the sensor.Furthermore,the in situ generated GY-Fe^(3+)ensemble could recover the quenched fluorescence upon the addition of H_(2)PO_(4)^(−)anion resulting in an off-on-type sensing with a detection limit of micromolar range in the same medium,and other anions,including F^(−),Cl^(−),Br^(−),I^(−),AcO^(−),HSO^(−)_(4),ClO^(−)_(4)and CN−had nearly no influence on the probing behavior.The test strips based on 2-[2-hydroxy-4-(diethylamino)phenyl]-1H-imidazo[4,5-b]phenazine and Fe^(3+)metal complex(GY-Fe^(3+))were fabricated,which could act as convenient and efficient H_(2)PO_(4)^(−)test kits.展开更多
Local cerebral perfusion pressure (CPP) is a primary factor controlling cerebral circulation and previous studies have indicated that the ratio of cerebral blood flow (CBF) to cerebral blood volume (CBV) can be ...Local cerebral perfusion pressure (CPP) is a primary factor controlling cerebral circulation and previous studies have indicated that the ratio of cerebral blood flow (CBF) to cerebral blood volume (CBV) can be used as an index of the local CPP. In this study, we investigated whether the CBF/CBV ratio differs among different brain structures under physiological conditions, by means of (15)O positron emission tomography. Nine healthy volunteers (5 men and 4 women; mean age, 47.0 ± 1.2 years) were studied by H2(15)O bolus injection for CBF measurement and by C(15)O inhalation for CBV measurement. The CBF/CBV ratio maps were created by dividing the CBF images by the CBV images after anatomical normalization. Regions of interest were placed on the CBF/CBV maps and comparing the regions. The mean CBF/ CBV ratio was highest in the cerebellum (19.3 + 5.2/ min), followed by the putamen (18.2 ± 3.9), pons (16.4 ±4.6), thalamus (14.5:1: 3.3), cerebral cortices (13.2 ±2.4), and centrum semiovale (1115 ± 2.1). The cerebellum and putamen showed significantly higher CBF/CBV ratios than the cerebral cortices and centrum semiovale. We created maps of the CBF/ CBV ratio in normal volunteers and demonstrated higher CBF/CBV ratios in the cerebellum and putamen than in the cerebral cortices and deep cerebral white matter. The CBF/CBV may reflect the local CPP and should be studied in hemodynamicallycompromised patients and in patients with risk factors for small-artery diseases of the brain. Keywords: cerebral perfusion pressure; cerebra blood flow; cerebral blood volume; H2(15)O; C(15)O展开更多
Chloroplasts overproduce reactive oxygen species(ROS)under unfavorable environmental conditions,and these ROS are implicated in both signaling and oxidative damage.There is mounting evidence for their roles in transla...Chloroplasts overproduce reactive oxygen species(ROS)under unfavorable environmental conditions,and these ROS are implicated in both signaling and oxidative damage.There is mounting evidence for their roles in translating environmental fluctuations into distinct physiological responses,but their targets,signaling cascades,and mutualism and antagonism with other stress signaling cascades and within ROS signaling remain poorly understood.Great efforts made in recent years have shed new light on chloroplast ROS-directed plant stress responses,from ROS perception to plant responses,in conditional mutants of Arabidopsis thaliana or under various stress conditions.Some articles have also reported the mechanisms underlying the complexity of ROS signaling pathways,with an emphasis on spatiotemporal regulation.ROS and oxidative modification of affected target proteins appear to induce retrograde signaling pathways to maintain chloroplast protein quality control and signaling at a whole-cell level using stress hormones.This review focuses on these seemingly interconnected chloroplast-to-nucleus retrograde signaling pathways initiated by ROS and ROS-modified target molecules.We also discuss future directions in chloroplast stress research to pave the way for discovering new signaling molecules and identifying intersectional signaling components that interact in multiple chloroplast signaling pathways.展开更多
基金This work is supported by the National Natural Science Foundation of China(No.22103075,No.21827804,and No.22173089)the National Key R&D Program of China(No.2021YFA0716801andNo.2017YFA0303502).
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11271158,11574117,and 61575077)the Natural Science Foundation of Jilin Province of China(Grants No.20180101225JC)
文摘By numerically solving the two-dimensional time-dependent Schr¨odinger equation under the frozen-nuclei approximation, we are able to study the molecular photoelectron-momentum distribution(MPMD) of H^+_2 with different orientation angles driven by elliptically polarized laser pulse with varying ellipticities. Our numerical results show that the MPMD is sensitive to the orientation angle and the laser ellipticity, which can be explained by the attosecond perturbation ionization theory and the exactly solvable photoionization model. When the ellipticity ε = 0, the final MPMD of x-oriented H^+_2 shows a distinct six-lobe pattern that is different from that with ε = 0.5 and ε = 1. The evolutions of electron wave packet(EWP)and MPMD with x-oriented H^+_2 are presented to interpret this distinct pattern.
基金Project(51164001)supported by the National Natural Science Foundation of China
文摘First-principles calculations are performed to investigate the relaxation and electronic properties of sulfide minerals surfaces(MoS2, Sb2S3, Cu2 S, ZnS, PbS and FeS2) in presence of H2 O molecule. The calculated results show that the structure and electronic properties of sulfide minerals surfaces have been influenced in presence of H2 O molecule. The adsorption of the flotation reagent at the interface of mineral-water would be different from that of mineral surface due to the changes of surface structures and electronic properties caused by H2 O molecule. Hence, the influence of H2 O molecule on the reaction of flotation reagent with sulfide mineral surface will attract more attention.
基金the National Natural Science Foundation of China (21376282,21676035,21878029)Chongqing Science and Technology Commission (cstc2018jcyjAX0668)+2 种基金Shandong Province Natural Science Foundation (ZR2020QB18)China Postdoctoral Science Foundation (22012 T50762&2011 M501388)Graduate Student Research Innovation Project,Chongqing University (CYB18046)。
文摘In this study,the benign target double terpyridine parts based amphiphilic ionic molecules(AIMs 1,2)and the reference single terpyridine segment included AIMs(AIMs 3,4)were synthesized through a multi-step method,and the molecular structures were fully characterized.The excellent anticorrosion of the target AIMs for copper surface in H_(2)SO_(4) solution was demonstrated by the electrochemistry analysis,which was more superior over those of the reference AIMs.The standard adsorption free energy changes of the target AIMs calculated by the adsorption isotherms were lower than -40 kJ·mol^(-1),suggesting an intensified chemical adsorption on metal surface.The molecular modeling and molecular dynamic computation of the studied AIMs were performed,demonstrating that the target AIMs exhibited lower highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps and greater adsorption energies than the reference ones.The chemical adsorption of the AIMs on metal surface was revealed by various spectroscopic methods including scanning electron microscopy,atomic force microscopy,Fourier transform infrared spectroscopy,attenuated total reflection infrared spectroscopy,Raman and X-ray diffraction.
基金the National Natural Science Foundation of China(Grant No.12075194)the Sichuan Provincial Science and Technology Program,China(Grant No.2020ZYD055)the National Key Research and Development Program of China(Grant No.2017YFE0301306).
文摘Lattice defects induced by ion implantation into SiC have been widely investigated in the decades by various techniques.One of the non-destructive techniques suitable to study the lattice defects in SiC is the optical characterization.In this work,confocal Raman scattering spectroscopy and photoluminescence spectrum have been used to study the effects of 134-keV H_(2)^(+)implantation and thermal treatment in the microstructure of 6H-SiC single crystal.The radiation-induced changes in the microstructure were assessed by integrating Raman-scattering peaks intensity and considering the asymmetry of Raman-scattering peaks.The integrated intensities of Raman scattering spectroscopy and photoluminescence spectrum decrease with increasing the fluence.The recovery of the optical intensities depends on the combination of the implantation temperature and the annealing temperature with the thermal treatment from 700℃to 1100℃.The different characterizations of Raman scattering spectroscopy and photoluminescence spectrum are compared and discussed in this study.
基金the National Natural Science Foundation of China (21773055, U1604122, 22005085)。
文摘Ether-based electrolytes with relatively high stability are widely used in Li-O_(2) batteries (LOBs) with high energy density.However,they are still prone to be attacked by reactive oxygen species.Understanding the degradation chemistry of ether-based solvent induced by reactive oxygen species is significant importance toward selection of stable electrolytes for LOBs.Herein,we demonstrate that a great amount of H_(2) gas evolves on the Li anode during the long-term discharge process of LOBs,which is due to the electrolyte decomposition at the oxygen cathode.By coupling with in-situ and ex-situ characterization techniques,it is demonstrated that O_(2)^(-) induces the H-abstraction of tetraethylene glycol dimethyl ether(TEGDME) to produce a large amount of H_(2)O at cathode,and this H_(2)O migrates to Li anode and produce H_(2) gas.Based on the established experiments and spectra,a possible decomposition pathway of TEGDME caused by O_(2)^(-)at the discharge process is proposed.And moreover,three types of strategies are discussed to inhibit the decomposition of ether-based electrolytes,which should be highly important for the fundamental and technical advancement for LOBs.
基金the Beijing Natural Science Foundation(JQ18005)the National Science Fund for Distinguished Young Scholars(52025133)+3 种基金the Tencent Foundation through the XPLORER PRIZEthe National Natural Science Foundation of China(22002003)China Postdoctoral Science Foundation(2019TQ0001,2020M670020)the Fund of the State Key Laboratory of Solidification Processing in Northwestern Polytechnic University(NWPU)(SKLSP202004)。
文摘Atomic sites co-catalyst (ASC) on photocatalytic materials possesses an attractive prospect to promote charge carrier separation and tune surface reaction kinetics,yet the synthesis of earth-abundant ASC under low temperature remains a great challenge.Here,a novel in-situ NH_(4)^(+)-etched strategy to anchor atomic Mo sites on ZnIn_(2)S_(4)hierarchical nanotubes (HNTs) with abundant mesopores under mild conditions for promoting charge carrier separation and enhancing light multi-reflections is developed for efficient photocatalytic H_(2) evolution.Density functional theory calculations and linear sweep voltammetry demonstrate that the well-defined Mo-S_(2)O_(1) sites with distinctive coordination configuration and electronic property contribute to the enhanced separation of photo-generated charge carriers and reduced Gibbs free energy for H_(2) evolution.Consequently,the well-defined MoSA-ZIS HNTs present an excellent photocatalytic activity with a rate of 29.9μmol h^(-1)(5.98 mmol g^(-1)h^(-1)),which is 7.3 times higher than that of ZnIn_(2)S_(4)nanosheets (NSs),to be among the best ZnIn_(2)S_(4)-based photocatalysts.The present strategy breaks the high-temperature limitation of conventional top-down thermal dissociation/emitting approach for anchoring non-noble metal atomic sites on catalyst support.
基金the National Natural Science Foundation of China(Nos.21872021,21671033,22172022 and 22071019).
文摘Molybdenum trioxide(MoO_(3))can be employed as an excellent host for intercalation due to its 2D lay-ered structure that connected by van der Waals interactions.Herein,a series of polyoxometalate-based MoO_(3) composites(Al_(13)@MoO_(3))were successfully prepared by interpolating the Keggin-type polycationic AlO_(4)Al_(12)(OH)_(24)H_(2)O_(12)^(7+)(Al_(13))into MoO_(3)gallery.These composites can be applied to rapidly adsorb the anionic dye methyl orange(MO)through strong electrostatic interactions lead to compact and sta-ble gathering in the surrounding of the numerous charged Al_(13).Adsorption behaviors of composites with the different amount of Al_(13) were determined,these results revealed that Al_(13)-3.34%@MoO_(3)exhibited the most remarkable adsorption capacity.More importantly,the composite maintains superior adsorption capacity for five consecutive adsorption/desorption cycles,suggesting that Al_(13)@MoO_(3)can be an efficient and durable adsorbent.
基金The Elementary Innovation Team Foundation supported by NORINCO Group in China(2021CXTD52)The Taishan Scholars Foundation supported by Shandong Provence in China。
基金This work was supported by the National Natural Science Foundation of China(Nos.21064006,21262032 and 21161018)the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China(No.IRT1177)+2 种基金the Natural Science Foundation of Gansu Province(No.1010RJZA018)the Youth Foundation of Gansu Province(No.2011GS04735)NWNU-LKQN-11-32.
文摘A long wavelength emission fluorescent(612 nm)chemosensor with high selectivity for H_(2)PO_(4)^(−)ions was designed and synthesized according to the excited state intramolecular proton transfer(ESIPT).The sensor can exist in two tautomeric forms(‘keto’and‘enol’)in the presence of Fe^(3+)ion,Fe^(3+)may bind with the‘keto’form of the sensor.Furthermore,the in situ generated GY-Fe^(3+)ensemble could recover the quenched fluorescence upon the addition of H_(2)PO_(4)^(−)anion resulting in an off-on-type sensing with a detection limit of micromolar range in the same medium,and other anions,including F^(−),Cl^(−),Br^(−),I^(−),AcO^(−),HSO^(−)_(4),ClO^(−)_(4)and CN−had nearly no influence on the probing behavior.The test strips based on 2-[2-hydroxy-4-(diethylamino)phenyl]-1H-imidazo[4,5-b]phenazine and Fe^(3+)metal complex(GY-Fe^(3+))were fabricated,which could act as convenient and efficient H_(2)PO_(4)^(−)test kits.
基金partly supported by the Molecular Imaging Program,a grant(21591561) from the Ministry of Education,Culture,Sports,Science,and Technology and the Japan Science and Technology Agency,Japanby the Research Promotion Program on Health from the National Institute of Biomedical Innovation,Japana Grant-in-Aid(H21-019 and H21-5) from the Ministry of Health,Welfare,and Labour,Japan
文摘Local cerebral perfusion pressure (CPP) is a primary factor controlling cerebral circulation and previous studies have indicated that the ratio of cerebral blood flow (CBF) to cerebral blood volume (CBV) can be used as an index of the local CPP. In this study, we investigated whether the CBF/CBV ratio differs among different brain structures under physiological conditions, by means of (15)O positron emission tomography. Nine healthy volunteers (5 men and 4 women; mean age, 47.0 ± 1.2 years) were studied by H2(15)O bolus injection for CBF measurement and by C(15)O inhalation for CBV measurement. The CBF/CBV ratio maps were created by dividing the CBF images by the CBV images after anatomical normalization. Regions of interest were placed on the CBF/CBV maps and comparing the regions. The mean CBF/ CBV ratio was highest in the cerebellum (19.3 + 5.2/ min), followed by the putamen (18.2 ± 3.9), pons (16.4 ±4.6), thalamus (14.5:1: 3.3), cerebral cortices (13.2 ±2.4), and centrum semiovale (1115 ± 2.1). The cerebellum and putamen showed significantly higher CBF/CBV ratios than the cerebral cortices and centrum semiovale. We created maps of the CBF/ CBV ratio in normal volunteers and demonstrated higher CBF/CBV ratios in the cerebellum and putamen than in the cerebral cortices and deep cerebral white matter. The CBF/CBV may reflect the local CPP and should be studied in hemodynamicallycompromised patients and in patients with risk factors for small-artery diseases of the brain. Keywords: cerebral perfusion pressure; cerebra blood flow; cerebral blood volume; H2(15)O; C(15)O
基金Research in the Kim laboratory has been supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(grant XDB27040102)the 100-Talent Program of the Chinese Academy of Sciences,and the National Natural Science Foundation of China(grant 31871397 to C.K.).
文摘Chloroplasts overproduce reactive oxygen species(ROS)under unfavorable environmental conditions,and these ROS are implicated in both signaling and oxidative damage.There is mounting evidence for their roles in translating environmental fluctuations into distinct physiological responses,but their targets,signaling cascades,and mutualism and antagonism with other stress signaling cascades and within ROS signaling remain poorly understood.Great efforts made in recent years have shed new light on chloroplast ROS-directed plant stress responses,from ROS perception to plant responses,in conditional mutants of Arabidopsis thaliana or under various stress conditions.Some articles have also reported the mechanisms underlying the complexity of ROS signaling pathways,with an emphasis on spatiotemporal regulation.ROS and oxidative modification of affected target proteins appear to induce retrograde signaling pathways to maintain chloroplast protein quality control and signaling at a whole-cell level using stress hormones.This review focuses on these seemingly interconnected chloroplast-to-nucleus retrograde signaling pathways initiated by ROS and ROS-modified target molecules.We also discuss future directions in chloroplast stress research to pave the way for discovering new signaling molecules and identifying intersectional signaling components that interact in multiple chloroplast signaling pathways.