Unreduced gametes through chromosome doubling play a major role in the process of plant polyploidization.Our previous work confirmed that Camellia oleifera can produce natural 2n pollen,and it is possible to induce th...Unreduced gametes through chromosome doubling play a major role in the process of plant polyploidization.Our previous work confirmed that Camellia oleifera can produce natural 2n pollen,and it is possible to induce the 2n pollen formation by high temperature treatment.This study focused on the optimization of the 2n pollen induction technique and the mechanisms of high temperature-induced2n pollen formation in C.oleifera.We found that the optimal protocol for inducing 2n pollen via high temperature was to perform 45℃with4 h at the prophaseⅠstage of the pollen mother cells(PMCs).Meanwhile,high temperature significantly decreased the yield and fertility of2n pollen.Through the observation of meiosis,abnormal chromosome and cytological behaviour was discovered under high-temperature treatment,and we confirmed that the formation of 2n pollen is caused by abnormal cell plate.Based on weighted gene co-expression network analysis,fifteen hub genes related to cell cycle control were identified.After male flower buds were exposed to heat shock,polygalacturonase gene(CoPGX3)was significantly upregulated.We inferred that high temperature causes the CoPGX3 gene to be overexpressed and that CoPGX3 is redistributed into the cytosol where it degrades cytoplasmic pectin,which leads to an abnormal cell plate.Furthermore,abnormal cytokinesis resulted in the formation of dyads and triads,and PMCs divided to produce 2n pollen.Our findings provide new insights into the mechanism of 2n pollen induced by high temperature in a woody plant and lay a foundation for further ploidy breeding of C.oleifera.展开更多
Finesse is a critical parameter for describing the characteristics of an optical enhancement cavity(OEC). This paper first presents a review of finesse measurement techniques, including a comparative analysis of the a...Finesse is a critical parameter for describing the characteristics of an optical enhancement cavity(OEC). This paper first presents a review of finesse measurement techniques, including a comparative analysis of the advantages, disadvantages, and potential limitations of several main methods from both theoretical and practical perspectives. A variant of the existing method called the free spectral range(FSR) modulation method is proposed and compared with three other finesse measurement methods, i.e., the fast-switching cavity ring-down(CRD) method, the rapidly swept-frequency(SF) CRD method, and the ringing effect method. A high-power OEC platform with a high finesse of approximately 16000 is built and measured with the four methods. The performance of these methods is compared, and the results show that the FSR modulation method and the fast-switching CRD method are more suitable and accurate than the other two methods for high-finesse OEC measurements. The CRD method and the ringing effect method can be implemented in open loop using simple equipment and are easy to perform. Additionally, recommendations for selecting finesse measurement methods under different conditions are proposed, which benefit the development of OEC and its applications.展开更多
Aluminum(Al)toxicity poses a significant constraint on field crop yields in acid soils.Zinc finger protein36(ZFP36)is well-documented for its pivotal role in enhancing tolerance to both drought and oxidative stress in...Aluminum(Al)toxicity poses a significant constraint on field crop yields in acid soils.Zinc finger protein36(ZFP36)is well-documented for its pivotal role in enhancing tolerance to both drought and oxidative stress in rice.This study unveils a novel function of ZFP36 modulated by abscisic acid(ABA)-dependent mechanisms,specifically aimed at alleviating Al toxicity in rice.Under Al stress,the expression of ZFP36significantly increased through an ABA-dependent pathway.Knocking down ZFP36 heightened Al sensitivity,while overexpressing ZFP36 conferred increased resistance to Al stress.Additionally,our investigations revealed a physical interaction between ZFP36 and pyruvate dehydrogenase kinase 1 in rice(OsPDK1).Biochemical assays further elucidated that OsPDK1 phosphorylates ZFP36 at the amino acid site 73–161.Subsequent experiments demonstrated that ZFP36 positively regulates the expression of ascorbate peroxidases(OsAPX1)and OsALS1 by binding to specific elements in their upstream segments in rice.Through genetic and phenotypic analyses,we unveiled that OsPDK1 influences ABA-triggered antioxidant defense to alleviate Al toxicity by interacting with ZFP36.In summary,our study underscores that pyruvate dehydrogenase kinase 1(OsPDK1)phosphorylates ZFP36 to modulate the activities of antioxidant enzymes via an ABA-dependent pathway,influencing tolerance of rice to soil Al toxicity.展开更多
A three-dimensional, two-temperature(2T) model of a lamellar cathode arc is constructed,drawing upon the conservation equations for mass, momentum, electron energy, and heavy particle energy, in addition to Maxwell...A three-dimensional, two-temperature(2T) model of a lamellar cathode arc is constructed,drawing upon the conservation equations for mass, momentum, electron energy, and heavy particle energy, in addition to Maxwell's equations. The model aims to elucidate how the physical properties of electrons and heavy particles affect heat transfer and fluid flow in a lamellar cathode arc. This is achieved by solving and comparing the fields of electron temperature,heavy particle temperature, fluid flow, current density, and Lorentz force distribution under varying welding currents. The results show that the guiding effect of the lamellar cathode on current density, the inertial drag effect of moving arc, and the attraction effect of Lorentz force at the lamellar cathode tip primarily govern the distribution of the arc's physical fields. The guiding effect localizes the current density to the front end of the lamellar cathode, particularly where the discharge gap is minimal. Both the inertial drag effect and the attraction effect of Lorentz force direct arc flow toward its periphery. Under the influence of the aforementioned factors, the physical fields of the lamellar cathode arc undergo expansion and shift counter to the arc's direction of motion. A reduction in welding current substantially weakens the guiding effect,causing the arc's physical fields to deviate further in the direction opposite to the arc motion. In comparison with a cylindrical cathode arc, the physical fields of the lamellar cathode arc are markedly expanded, leading to a reduction in current density, electron temperature, heavy particle temperature, cathode jet flow velocity, and Lorentz force.展开更多
BACKGROUND Chronic renal failure(CRF) patients are predisposed to arrhythmias, while the detailed mechanisms are unclear. We hypothesized the chronic inflammatory state of CRF patients may lead to cardiac sympathetic ...BACKGROUND Chronic renal failure(CRF) patients are predisposed to arrhythmias, while the detailed mechanisms are unclear. We hypothesized the chronic inflammatory state of CRF patients may lead to cardiac sympathetic remodeling, increasing the incidence of ventricular arrhythmia(VA) and sudden cardiac death. And explored the role of atorvastatin and etanercept in this process.METHODS A total of 48 rats were randomly divided into sham operation group(Sham group), CRF group, CRF + atorvastatin group(CRF + statin group), and CRF + etanercept group(CRF + rhTNFR-Fcgroup). Sympathetic nerve remodeling was assessed by immunofluorescence of growth-associated protein 43(GAP-43) and tyrosine hydroxylase positive area fraction. Electrophysiological testing was performed to assess the incidence of VA by assessing the ventricular effective refractory period and ventricular fibrillation threshold. The levels of tumor necrosis factor-alpha(TNF-α) and interleukin-1beta were determined by Western blotting and enzyme-linked immunosorbent assay.RESULTS Echocardiogram showed that compared with the Sham group, left ventricular end-systolic diameter and ventricular weight/body weight ratio were significantly higher in the CRF group. Hematoxylin-eosin and Masson staining indicated that myocardial fibers were broken, disordered, and fibrotic in the CRF group. Western blotting, enzyme-linked immunosorbent assay,immunofluorescence and electrophysiological examination suggested that compared with the Sham group, GAP-43 and TNF-α proteins were significantly upregulated, GAP-43 and tyrosine hydroxylase positive nerve fiber area was increased, and ventricular fibrillation threshold was significantly decreased in the CRF group. The above effects were inhibited in the CRF + statin group and the CRF + rhTNFR-Fcgroup.CONCLUSIONS In CRF rats, TNF-α was upregulated, cardiac sympathetic remodeling was more severe, and the nephrogenic cardiac sympathetic remodeling existed. Atorvastatin and etanercept could downregulate the expression of TNF-α or inhibit its activity, thus inhibited the above effects, and reduced the occurrence of VA and sudden cardiac death.展开更多
Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S...Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S_(4) heterostructures with strong hetero-interface interaction and abundant contact were constructed via an impregnation-annealing strategy.Efficient charge transfer from ZnIn_(2)S_(4) to WSe_(2)was evidenced by transient absorption spectroscopy in crafted heterostructures owing to the tight and2D face-to-face contact.As a result,the prepared WSe_(2)/ZnIn_(2)S_(4) heterostructures exhibited boosted photocatalytic performance and a highest hydrogen evolution rate of 3.377 mmol/(g h)was achieved with an apparent quantum yield of 45.7%at 420 nm.The work not only provides new strategies to achieve efficient 2D/2D heterostructures but also paves the way for the development of green hydrogen in the future.展开更多
Background: With the development of high quality nursing service, hospitals put forward higher requirements for nurses’ service level. In recent years, the number and quality of specialized nurses remain to be improv...Background: With the development of high quality nursing service, hospitals put forward higher requirements for nurses’ service level. In recent years, the number and quality of specialized nurses remain to be improved despite the remarkable achievements in the construction of specialized nurses. Objective: This study intended to explore a standardized training mode for nurses oriented by training and assessment of nursespecialty knowledge and to summarize the practical experience of this mode. Methods: The training and assessment program was formulated by starting from the objectives of training clinical front-line nursing staff in our hospital, and the standard training and assessment were carried out from four aspects: the specialized disease knowledge, the condition observation and reporting ability, emergency and severe disease nursing, and perioperative accelerated rehabilitation guidance. These four items are hereinafter referred to as “Four Passes” training and assessment, and it was practiced in the assessment and training of nurses in our hospital from 2020 to 2022. Results: A total of 915 front-line caregivers were surveyed in our study, including 772 nurses and 143 doctors. After two years of implementation, the self-evaluation of nurses increased from (2.96 ± 0.79) points to (3.64 ± 0.78) points, and the evaluation score by doctors increased from (3.94 ± 0.74) points to (4.26 ± 0.72) points. The core competence of specialty increased from (69.22 ± 16.53) points to (85.42 ± 14.44) points. The scores of all dimensions after training were higher than those before training, with statistical significances. Conclusion: The “Four Passes” training and assessment of nurse specialty knowledge can fully mobilize the enthusiasm of managers and nurses in all departments, ensure solid specialty knowledge, improve nurses’ core competence, improve nursing quality, and create a harmonious relationship between nurses and patients as well as between doctors and patients.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.32101489)Forestry Science and Technology Innovation Program of Hunan Province(Grant No.XLK202101-2)Science and Technology Innovation Platform and Talent Program of Hunan Province(Grant Nos.2023RC3164,2021NK1007)。
文摘Unreduced gametes through chromosome doubling play a major role in the process of plant polyploidization.Our previous work confirmed that Camellia oleifera can produce natural 2n pollen,and it is possible to induce the 2n pollen formation by high temperature treatment.This study focused on the optimization of the 2n pollen induction technique and the mechanisms of high temperature-induced2n pollen formation in C.oleifera.We found that the optimal protocol for inducing 2n pollen via high temperature was to perform 45℃with4 h at the prophaseⅠstage of the pollen mother cells(PMCs).Meanwhile,high temperature significantly decreased the yield and fertility of2n pollen.Through the observation of meiosis,abnormal chromosome and cytological behaviour was discovered under high-temperature treatment,and we confirmed that the formation of 2n pollen is caused by abnormal cell plate.Based on weighted gene co-expression network analysis,fifteen hub genes related to cell cycle control were identified.After male flower buds were exposed to heat shock,polygalacturonase gene(CoPGX3)was significantly upregulated.We inferred that high temperature causes the CoPGX3 gene to be overexpressed and that CoPGX3 is redistributed into the cytosol where it degrades cytoplasmic pectin,which leads to an abnormal cell plate.Furthermore,abnormal cytokinesis resulted in the formation of dyads and triads,and PMCs divided to produce 2n pollen.Our findings provide new insights into the mechanism of 2n pollen induced by high temperature in a woody plant and lay a foundation for further ploidy breeding of C.oleifera.
基金Project supported by National Key Research and Development Program of China (Grant No.2022YFA1603403)。
文摘Finesse is a critical parameter for describing the characteristics of an optical enhancement cavity(OEC). This paper first presents a review of finesse measurement techniques, including a comparative analysis of the advantages, disadvantages, and potential limitations of several main methods from both theoretical and practical perspectives. A variant of the existing method called the free spectral range(FSR) modulation method is proposed and compared with three other finesse measurement methods, i.e., the fast-switching cavity ring-down(CRD) method, the rapidly swept-frequency(SF) CRD method, and the ringing effect method. A high-power OEC platform with a high finesse of approximately 16000 is built and measured with the four methods. The performance of these methods is compared, and the results show that the FSR modulation method and the fast-switching CRD method are more suitable and accurate than the other two methods for high-finesse OEC measurements. The CRD method and the ringing effect method can be implemented in open loop using simple equipment and are easy to perform. Additionally, recommendations for selecting finesse measurement methods under different conditions are proposed, which benefit the development of OEC and its applications.
基金provided by the National Natural Science Foundation of China (31901202,31672228)National Distinguished Expert Project (WQ20174400441)+2 种基金the Higher Education Department of Guangdong province (2020KCXTD025)Key Laboratory Project of Guangdong Province (2022B1212010015)the Australian Research Council (DP150101663)。
文摘Aluminum(Al)toxicity poses a significant constraint on field crop yields in acid soils.Zinc finger protein36(ZFP36)is well-documented for its pivotal role in enhancing tolerance to both drought and oxidative stress in rice.This study unveils a novel function of ZFP36 modulated by abscisic acid(ABA)-dependent mechanisms,specifically aimed at alleviating Al toxicity in rice.Under Al stress,the expression of ZFP36significantly increased through an ABA-dependent pathway.Knocking down ZFP36 heightened Al sensitivity,while overexpressing ZFP36 conferred increased resistance to Al stress.Additionally,our investigations revealed a physical interaction between ZFP36 and pyruvate dehydrogenase kinase 1 in rice(OsPDK1).Biochemical assays further elucidated that OsPDK1 phosphorylates ZFP36 at the amino acid site 73–161.Subsequent experiments demonstrated that ZFP36 positively regulates the expression of ascorbate peroxidases(OsAPX1)and OsALS1 by binding to specific elements in their upstream segments in rice.Through genetic and phenotypic analyses,we unveiled that OsPDK1 influences ABA-triggered antioxidant defense to alleviate Al toxicity by interacting with ZFP36.In summary,our study underscores that pyruvate dehydrogenase kinase 1(OsPDK1)phosphorylates ZFP36 to modulate the activities of antioxidant enzymes via an ABA-dependent pathway,influencing tolerance of rice to soil Al toxicity.
基金National Natural Science Foundation of China (No. 51605384)the Natural Science Foundation of Gansu Province,China (No. 21JR7RA308)。
文摘A three-dimensional, two-temperature(2T) model of a lamellar cathode arc is constructed,drawing upon the conservation equations for mass, momentum, electron energy, and heavy particle energy, in addition to Maxwell's equations. The model aims to elucidate how the physical properties of electrons and heavy particles affect heat transfer and fluid flow in a lamellar cathode arc. This is achieved by solving and comparing the fields of electron temperature,heavy particle temperature, fluid flow, current density, and Lorentz force distribution under varying welding currents. The results show that the guiding effect of the lamellar cathode on current density, the inertial drag effect of moving arc, and the attraction effect of Lorentz force at the lamellar cathode tip primarily govern the distribution of the arc's physical fields. The guiding effect localizes the current density to the front end of the lamellar cathode, particularly where the discharge gap is minimal. Both the inertial drag effect and the attraction effect of Lorentz force direct arc flow toward its periphery. Under the influence of the aforementioned factors, the physical fields of the lamellar cathode arc undergo expansion and shift counter to the arc's direction of motion. A reduction in welding current substantially weakens the guiding effect,causing the arc's physical fields to deviate further in the direction opposite to the arc motion. In comparison with a cylindrical cathode arc, the physical fields of the lamellar cathode arc are markedly expanded, leading to a reduction in current density, electron temperature, heavy particle temperature, cathode jet flow velocity, and Lorentz force.
基金supported by the Key Project of Tianjin Natural Science Foundation (No.21JCZDJC01080)the Tianjin Key Medical Discipline (Specialty) (TJYXZDX K-029A)+1 种基金the Academic Backbone of “Clinical Talent Training and Climbing Plan” of Tianjin Medical University and the Tianjin Health Research ProjectScience and Technology Development Fund of Nanjing Medical University (NMUB20210180)。
文摘BACKGROUND Chronic renal failure(CRF) patients are predisposed to arrhythmias, while the detailed mechanisms are unclear. We hypothesized the chronic inflammatory state of CRF patients may lead to cardiac sympathetic remodeling, increasing the incidence of ventricular arrhythmia(VA) and sudden cardiac death. And explored the role of atorvastatin and etanercept in this process.METHODS A total of 48 rats were randomly divided into sham operation group(Sham group), CRF group, CRF + atorvastatin group(CRF + statin group), and CRF + etanercept group(CRF + rhTNFR-Fcgroup). Sympathetic nerve remodeling was assessed by immunofluorescence of growth-associated protein 43(GAP-43) and tyrosine hydroxylase positive area fraction. Electrophysiological testing was performed to assess the incidence of VA by assessing the ventricular effective refractory period and ventricular fibrillation threshold. The levels of tumor necrosis factor-alpha(TNF-α) and interleukin-1beta were determined by Western blotting and enzyme-linked immunosorbent assay.RESULTS Echocardiogram showed that compared with the Sham group, left ventricular end-systolic diameter and ventricular weight/body weight ratio were significantly higher in the CRF group. Hematoxylin-eosin and Masson staining indicated that myocardial fibers were broken, disordered, and fibrotic in the CRF group. Western blotting, enzyme-linked immunosorbent assay,immunofluorescence and electrophysiological examination suggested that compared with the Sham group, GAP-43 and TNF-α proteins were significantly upregulated, GAP-43 and tyrosine hydroxylase positive nerve fiber area was increased, and ventricular fibrillation threshold was significantly decreased in the CRF group. The above effects were inhibited in the CRF + statin group and the CRF + rhTNFR-Fcgroup.CONCLUSIONS In CRF rats, TNF-α was upregulated, cardiac sympathetic remodeling was more severe, and the nephrogenic cardiac sympathetic remodeling existed. Atorvastatin and etanercept could downregulate the expression of TNF-α or inhibit its activity, thus inhibited the above effects, and reduced the occurrence of VA and sudden cardiac death.
基金financially supported by the National Natural Science Foundation of China (No.52106259)the Fundamental Research Funds for the Central Universities (2024MS013)Key Research and Development Program of Shaanxi (Program No.2022LL-JB-08)。
文摘Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S_(4) heterostructures with strong hetero-interface interaction and abundant contact were constructed via an impregnation-annealing strategy.Efficient charge transfer from ZnIn_(2)S_(4) to WSe_(2)was evidenced by transient absorption spectroscopy in crafted heterostructures owing to the tight and2D face-to-face contact.As a result,the prepared WSe_(2)/ZnIn_(2)S_(4) heterostructures exhibited boosted photocatalytic performance and a highest hydrogen evolution rate of 3.377 mmol/(g h)was achieved with an apparent quantum yield of 45.7%at 420 nm.The work not only provides new strategies to achieve efficient 2D/2D heterostructures but also paves the way for the development of green hydrogen in the future.
文摘Background: With the development of high quality nursing service, hospitals put forward higher requirements for nurses’ service level. In recent years, the number and quality of specialized nurses remain to be improved despite the remarkable achievements in the construction of specialized nurses. Objective: This study intended to explore a standardized training mode for nurses oriented by training and assessment of nursespecialty knowledge and to summarize the practical experience of this mode. Methods: The training and assessment program was formulated by starting from the objectives of training clinical front-line nursing staff in our hospital, and the standard training and assessment were carried out from four aspects: the specialized disease knowledge, the condition observation and reporting ability, emergency and severe disease nursing, and perioperative accelerated rehabilitation guidance. These four items are hereinafter referred to as “Four Passes” training and assessment, and it was practiced in the assessment and training of nurses in our hospital from 2020 to 2022. Results: A total of 915 front-line caregivers were surveyed in our study, including 772 nurses and 143 doctors. After two years of implementation, the self-evaluation of nurses increased from (2.96 ± 0.79) points to (3.64 ± 0.78) points, and the evaluation score by doctors increased from (3.94 ± 0.74) points to (4.26 ± 0.72) points. The core competence of specialty increased from (69.22 ± 16.53) points to (85.42 ± 14.44) points. The scores of all dimensions after training were higher than those before training, with statistical significances. Conclusion: The “Four Passes” training and assessment of nurse specialty knowledge can fully mobilize the enthusiasm of managers and nurses in all departments, ensure solid specialty knowledge, improve nurses’ core competence, improve nursing quality, and create a harmonious relationship between nurses and patients as well as between doctors and patients.
