Dynamic tidal power is a new way of capturing tidal energy by building a water head using a dike perpendicular to the coast. This study explored the hydrodynamic mechanism of the water head across an intended dynamic ...Dynamic tidal power is a new way of capturing tidal energy by building a water head using a dike perpendicular to the coast. This study explored the hydrodynamic mechanism of the water head across an intended dynamic tidal power dike system using the Delft3 D-FLOW software module. The propagating wave was simulated in a rectangular domain with a horizontal sea bottom at a 30-m depth. A significant water head was created across the dike by blocking the water. The water head increased with increasing dike length and increasing undisturbed tidal current acceleration. The maximum water head for the dike with a length of 50 km, located 900 km from the western boundary, was 2.15 m,which exceeded the undisturbed tidal range. The time series of the water head behaved in a manner identical to the undisturbed tidal current acceleration. The distribution of the water head over the dike assumed an elliptical shape. A parasitic wave was generated at the attachment and scattered outward. The phase lag across the dike did not behave as a linear function of the detour distance.展开更多
Well-crystalline CeO_2 nanowires were prepared via a surfactant-assisted hydrothermal process.Reaction temperature and reaction time were changed for the determination of optimal synthesis parameters.The as-obtained p...Well-crystalline CeO_2 nanowires were prepared via a surfactant-assisted hydrothermal process.Reaction temperature and reaction time were changed for the determination of optimal synthesis parameters.The as-obtained products were characterized by X-ray diffraction （XRD）,high-resolution transmission electron microscopy（HRTEM）,and field emission scanning electron microscopy（FESEM）.The results show that single crystal CeO_2 nanowires with high yield and good uniformity can be obtained hydrothermally at 180℃for 12 h with the aid of 2.0 g surfactant（polyvinyl pyrrolidone,PVP）.The role of PVP was then discussed and a possible growth mechanism was proposed. Moreover,room temperature photoluminescence（PL） spectra were obtained for these CeO2 nanowires,which are believed to be related to the abundant defects in these nanostructures.展开更多
An Asparagus officinalis L. cultivar NJ978 was used to study the growing rate, salt ion content and mineral ion uptake and distribution in plants under salt stress. The results showed that salt stress significantly in...An Asparagus officinalis L. cultivar NJ978 was used to study the growing rate, salt ion content and mineral ion uptake and distribution in plants under salt stress. The results showed that salt stress significantly inhibited seedling growth and there was a negative relationship between seedling growth and salt concentration. The seedlings growth showed no significant decrease under low salt stress （NaCl≤50 mmol/L）, while high concentrations of NaCl led to detrimental effects on the growth of A. officinalis L.. With the increase of NaCl concentration, the Na ＋ content increased gradually in A. officinalis L. roots, stems and leaves while the K^＋ and Ca^2＋ contents had slow decreases. Under low salt stress, the seedlings of A. officinalis L. could prevent Na ＋ from transporting to aerial part by withholding Na ＋ in root, which could keep the balance of ions in aerial part, but under high salt stress （NaCl 〉 100 mmol/L）, the aerial part of seedlings accumulated superabundance of Na ＋, which limited the uptake of K^＋ and Ca^2＋ , so seedlings were damaged heavily, which manifested as the gradual decrease of K^＋/Na ＋ and Ca^2＋ /Na ＋ in the roots and aerial part of the seedlings. The selective absorption of K^＋, Ca^2＋ and Na ＋ （AS K,Na and AS Ca,Na ） was significantly increased with increased salinity, while the selective transportation （TS K,Na and TS Ca,Na ） increased at first and then decreased with the increased salinity. Therefore, the strong ability of salt exclusion and the regionalized distribution of ions in roots, stems and leaves could be one of the salt tolerance mechanisms of A. officinalis L.展开更多
Cytosine base editing achieves C·G-to-T·A substitutions and can convert four codons(CAA/CAG/CGA/TGG)into STOP-codons(induction of STOP-codons,iSTOP)to knock out genes with reduced mosaicism.iSTOP enables dir...Cytosine base editing achieves C·G-to-T·A substitutions and can convert four codons(CAA/CAG/CGA/TGG)into STOP-codons(induction of STOP-codons,iSTOP)to knock out genes with reduced mosaicism.iSTOP enables direct phenotyping in founders’somatic cells,but it remains unknown whether this works in founders’germ cells so as to rapidly reveal novel genes for fertility.Here,we initially establish that iSTOP in mouse zygotes enables functional characterization of known genes in founders’germ cells:Cfap43-iSTOP male founders manifest expected sperm features resembling human“multiple morphological abnormalities of the flagella”syndrome(i.e.,MMAF-like features),while oocytes of Zp3-iSTOP female founders have no zona pellucida.We further illustrate iSTOP’s utility for dissecting the functions of unknown genes with Ccdc183,observing MMAF-like features and male infertility in Ccdc183-iSTOP founders,phenotypes concordant with those of Ccdc183-KO offspring.We ultimately establish that CCDC183 is essential for sperm morphogenesis through regulating the assembly of outer dynein arms and participating in the intra-flagellar transport.Our study demonstrates iSTOP as an efficient tool for direct reproductive disease modeling and phenotyping in germ cells of the founder generation,and rapidly reveals the essentiality of Ccdc183 in fertility,thus providing a time-saving approach for validating genetic defects(like nonsense mutations)for human infertility.展开更多
During spermiogenesis,haploid spermatids undergo dramatic morphological changes to form slender sperm flagella and cap-like acrosomes,which are required for successful fertilization.Severe deformities in flagella caus...During spermiogenesis,haploid spermatids undergo dramatic morphological changes to form slender sperm flagella and cap-like acrosomes,which are required for successful fertilization.Severe deformities in flagella cause a male infertility syndrome,multiple morphological abnormalities of the flagella(MMAF),while acrosomal hypoplasia in some cases leads to sub-optimal embryonic developmental potential.However,evidence regarding the occurrence of acrosomal hypoplasia in MMAF is limited.Here,we report the generation of base-edited mice knocked out for coiled-coil domain-containing 38(Ccdc38)via inducing a nonsense mutation and find that the males are infertile.The Ccdc38-KO sperm display acrosomal hypoplasia and typical MMAF phenotypes.We find that the acrosomal membrane is loosely anchored to the nucleus and fibrous sheaths are disorganized in Ccdc38-KO sperm.Further analyses reveal that Ccdc38 knockout causes a decreased level of TEKT3,a protein associated with acrosome biogenesis,in testes and an aberrant distribution of TEKT3 in sperm.We finally show that intracytoplasmic sperm injection overcomes Ccdc38-related infertility.Our study thus reveals a previously unknown role for CCDC38 in acrosome biogenesis and provides additional evidence for the occurrence of acrosomal hypoplasia in MMAF.展开更多
Renewable energy technologies are central to emissions reduction and essential to achieve net-zero emission.Segmented thermoelectric generators(STEG)facilitate more efficient thermal energy recovery over a large tempe...Renewable energy technologies are central to emissions reduction and essential to achieve net-zero emission.Segmented thermoelectric generators(STEG)facilitate more efficient thermal energy recovery over a large temperature gradient.However,the additional design complexity has introduced challenges in the modelling and optimization of its performance.In this work,an artificial neural network(ANN)has been applied to build accurate and fast forward modelling of the STEG.More importantly,we adopt an iterative method in the ANN training process to improve accuracy without increasing the dataset size.This approach strengthens the proportion of the high-power performance in the STEG training dataset.Without increasing the size of the training dataset,the relative prediction error over high-power STEG designs decreases from 0.06 to 0.02,representing a threefold improvement.Coupling with a genetic algorithm,the trained artificial neural networks can perform design optimization within 10 s for each operating condition.It is over 5,000 times faster than the optimization performed by the conventional finite element method.Such an accurate and fast modeller also allows mapping of the STEG power against different parameters.The modelling approach demonstrated in this work indicates its future application in designing and optimizing complex energy harvesting technologies.展开更多
Hydrogen peroxide （H2O2） is generated in many metabolic processes. As a signaling molecule, H2O2 plays important roles in plant growth and development, as well as environmental stress response. In Arabidopsis, there...Hydrogen peroxide （H2O2） is generated in many metabolic processes. As a signaling molecule, H2O2 plays important roles in plant growth and development, as well as environmental stress response. In Arabidopsis, there are three catalase genes, CAT1, CAT2, and CAT3. The encoded catalases are predominately peroxisomal pro- teins and are critical for scavenging H2O2. Since CAT1 and CAT3 are linked on chromosome 1, it has been almost impossible to generate cat1/3 and cats1/2/3 mutants by traditional genetic tools. In this study, we constructed cat1/3 double mutants and cat1/22/3 triple mutants by CRISPR/Cas9 to investigate the role of catalases. The cat1/ 2/3 triple mutants displayed severe redox disturbance and growth defects under physiological conditionscompared with wild-type and the cat2/3 double mutants. Transcriptome analysis showed a more profound tran- scriptional response in the cat1/2/3 triple mutants compared to the cat2/3 mutants. These differentially expressed genes are involved in plant growth regulation as well as abiotic and biotic stress responses. In addition, expression of OXI1 （OXIDATIVE SIGNAL INDUCIBLE 1） and several MAPK cascade genes were changed dramatically in the catalase triple mutant, suggesting that H2O2 produced in peroxisomes could serve as a peroxisomal retrograde signal.展开更多
基金supported by the National Key R&D Program of China(Grant No.2017YFC1404200)the National Natural Science Foundation of China(Grants No.51520105014 and 51509168)the National Special Funds for Basic Scientific Research for Research Institutes(Grant No.Y218008)
文摘Dynamic tidal power is a new way of capturing tidal energy by building a water head using a dike perpendicular to the coast. This study explored the hydrodynamic mechanism of the water head across an intended dynamic tidal power dike system using the Delft3 D-FLOW software module. The propagating wave was simulated in a rectangular domain with a horizontal sea bottom at a 30-m depth. A significant water head was created across the dike by blocking the water. The water head increased with increasing dike length and increasing undisturbed tidal current acceleration. The maximum water head for the dike with a length of 50 km, located 900 km from the western boundary, was 2.15 m,which exceeded the undisturbed tidal range. The time series of the water head behaved in a manner identical to the undisturbed tidal current acceleration. The distribution of the water head over the dike assumed an elliptical shape. A parasitic wave was generated at the attachment and scattered outward. The phase lag across the dike did not behave as a linear function of the detour distance.
基金supported by the National Natural Science Foundation of China(Nos.50901074 and 50672001)the Young Teacher Natural Science Fund of Anhui Province,China(No.2008jq1002).
文摘Well-crystalline CeO_2 nanowires were prepared via a surfactant-assisted hydrothermal process.Reaction temperature and reaction time were changed for the determination of optimal synthesis parameters.The as-obtained products were characterized by X-ray diffraction （XRD）,high-resolution transmission electron microscopy（HRTEM）,and field emission scanning electron microscopy（FESEM）.The results show that single crystal CeO_2 nanowires with high yield and good uniformity can be obtained hydrothermally at 180℃for 12 h with the aid of 2.0 g surfactant（polyvinyl pyrrolidone,PVP）.The role of PVP was then discussed and a possible growth mechanism was proposed. Moreover,room temperature photoluminescence（PL） spectra were obtained for these CeO2 nanowires,which are believed to be related to the abundant defects in these nanostructures.
基金Supported by the Science and Technology Support Program of Hebei Province(17226913D)the Project for Innovation of Hebei Province(F17R07)
文摘An Asparagus officinalis L. cultivar NJ978 was used to study the growing rate, salt ion content and mineral ion uptake and distribution in plants under salt stress. The results showed that salt stress significantly inhibited seedling growth and there was a negative relationship between seedling growth and salt concentration. The seedlings growth showed no significant decrease under low salt stress （NaCl≤50 mmol/L）, while high concentrations of NaCl led to detrimental effects on the growth of A. officinalis L.. With the increase of NaCl concentration, the Na ＋ content increased gradually in A. officinalis L. roots, stems and leaves while the K^＋ and Ca^2＋ contents had slow decreases. Under low salt stress, the seedlings of A. officinalis L. could prevent Na ＋ from transporting to aerial part by withholding Na ＋ in root, which could keep the balance of ions in aerial part, but under high salt stress （NaCl 〉 100 mmol/L）, the aerial part of seedlings accumulated superabundance of Na ＋, which limited the uptake of K^＋ and Ca^2＋ , so seedlings were damaged heavily, which manifested as the gradual decrease of K^＋/Na ＋ and Ca^2＋ /Na ＋ in the roots and aerial part of the seedlings. The selective absorption of K^＋, Ca^2＋ and Na ＋ （AS K,Na and AS Ca,Na ） was significantly increased with increased salinity, while the selective transportation （TS K,Na and TS Ca,Na ） increased at first and then decreased with the increased salinity. Therefore, the strong ability of salt exclusion and the regionalized distribution of ions in roots, stems and leaves could be one of the salt tolerance mechanisms of A. officinalis L.
基金supported by the National Key Research and Development Program of China(2021YFC2701400)the National Natural Science Foundation of China(32000393,32322017,32288101)。
文摘Cytosine base editing achieves C·G-to-T·A substitutions and can convert four codons(CAA/CAG/CGA/TGG)into STOP-codons(induction of STOP-codons,iSTOP)to knock out genes with reduced mosaicism.iSTOP enables direct phenotyping in founders’somatic cells,but it remains unknown whether this works in founders’germ cells so as to rapidly reveal novel genes for fertility.Here,we initially establish that iSTOP in mouse zygotes enables functional characterization of known genes in founders’germ cells:Cfap43-iSTOP male founders manifest expected sperm features resembling human“multiple morphological abnormalities of the flagella”syndrome(i.e.,MMAF-like features),while oocytes of Zp3-iSTOP female founders have no zona pellucida.We further illustrate iSTOP’s utility for dissecting the functions of unknown genes with Ccdc183,observing MMAF-like features and male infertility in Ccdc183-iSTOP founders,phenotypes concordant with those of Ccdc183-KO offspring.We ultimately establish that CCDC183 is essential for sperm morphogenesis through regulating the assembly of outer dynein arms and participating in the intra-flagellar transport.Our study demonstrates iSTOP as an efficient tool for direct reproductive disease modeling and phenotyping in germ cells of the founder generation,and rapidly reveals the essentiality of Ccdc183 in fertility,thus providing a time-saving approach for validating genetic defects(like nonsense mutations)for human infertility.
基金supported by the National Key Research and Development Program of China(2021YFC2701400)in part by the National Natural Science Foundation of China(32000393 and 32288101).
文摘During spermiogenesis,haploid spermatids undergo dramatic morphological changes to form slender sperm flagella and cap-like acrosomes,which are required for successful fertilization.Severe deformities in flagella cause a male infertility syndrome,multiple morphological abnormalities of the flagella(MMAF),while acrosomal hypoplasia in some cases leads to sub-optimal embryonic developmental potential.However,evidence regarding the occurrence of acrosomal hypoplasia in MMAF is limited.Here,we report the generation of base-edited mice knocked out for coiled-coil domain-containing 38(Ccdc38)via inducing a nonsense mutation and find that the males are infertile.The Ccdc38-KO sperm display acrosomal hypoplasia and typical MMAF phenotypes.We find that the acrosomal membrane is loosely anchored to the nucleus and fibrous sheaths are disorganized in Ccdc38-KO sperm.Further analyses reveal that Ccdc38 knockout causes a decreased level of TEKT3,a protein associated with acrosome biogenesis,in testes and an aberrant distribution of TEKT3 in sperm.We finally show that intracytoplasmic sperm injection overcomes Ccdc38-related infertility.Our study thus reveals a previously unknown role for CCDC38 in acrosome biogenesis and provides additional evidence for the occurrence of acrosomal hypoplasia in MMAF.
基金supported by an EPSRC IAA funding.The authors acknowledge using the IRIDIS High-Performance Computing Facility and associated support services at the University of Southampton to complete this work.All data supporting this study are available from the University of Southampton repository at DOI:https://doi.org/10.5258/SOTON/D2454.
文摘Renewable energy technologies are central to emissions reduction and essential to achieve net-zero emission.Segmented thermoelectric generators(STEG)facilitate more efficient thermal energy recovery over a large temperature gradient.However,the additional design complexity has introduced challenges in the modelling and optimization of its performance.In this work,an artificial neural network(ANN)has been applied to build accurate and fast forward modelling of the STEG.More importantly,we adopt an iterative method in the ANN training process to improve accuracy without increasing the dataset size.This approach strengthens the proportion of the high-power performance in the STEG training dataset.Without increasing the size of the training dataset,the relative prediction error over high-power STEG designs decreases from 0.06 to 0.02,representing a threefold improvement.Coupling with a genetic algorithm,the trained artificial neural networks can perform design optimization within 10 s for each operating condition.It is over 5,000 times faster than the optimization performed by the conventional finite element method.Such an accurate and fast modeller also allows mapping of the STEG power against different parameters.The modelling approach demonstrated in this work indicates its future application in designing and optimizing complex energy harvesting technologies.
基金funded by the Foundation for Taishan Scholar from the People’s Government of Shandong Province (tshw20130962)National Natural Science Foundation of China (31470352, 31670073, and 31600204)+2 种基金Natural Science Foundation of Shandong Province (ZR2014CM002 and ZR2016CB05)China Postdoctoral Science Foundation (2017M612333)Research in the Zhao Laboratory was supported by the National Science Foundation (IOS-0721192 and IOS-1322796)
文摘Hydrogen peroxide （H2O2） is generated in many metabolic processes. As a signaling molecule, H2O2 plays important roles in plant growth and development, as well as environmental stress response. In Arabidopsis, there are three catalase genes, CAT1, CAT2, and CAT3. The encoded catalases are predominately peroxisomal pro- teins and are critical for scavenging H2O2. Since CAT1 and CAT3 are linked on chromosome 1, it has been almost impossible to generate cat1/3 and cats1/2/3 mutants by traditional genetic tools. In this study, we constructed cat1/3 double mutants and cat1/22/3 triple mutants by CRISPR/Cas9 to investigate the role of catalases. The cat1/ 2/3 triple mutants displayed severe redox disturbance and growth defects under physiological conditionscompared with wild-type and the cat2/3 double mutants. Transcriptome analysis showed a more profound tran- scriptional response in the cat1/2/3 triple mutants compared to the cat2/3 mutants. These differentially expressed genes are involved in plant growth regulation as well as abiotic and biotic stress responses. In addition, expression of OXI1 （OXIDATIVE SIGNAL INDUCIBLE 1） and several MAPK cascade genes were changed dramatically in the catalase triple mutant, suggesting that H2O2 produced in peroxisomes could serve as a peroxisomal retrograde signal.
