Purpose: This study aims to investigate the predictive value of blood calcium in the prognosis of traumatic fracture. Methods: A retrospective experimental design was employed, 112 cases (52 non-fracture and 60 trauma...Purpose: This study aims to investigate the predictive value of blood calcium in the prognosis of traumatic fracture. Methods: A retrospective experimental design was employed, 112 cases (52 non-fracture and 60 traumatic fracture) were randomly selected. The type of fracture complies with WHO-recommended (2019) diagnostic criteria for osteoporosis combined with fracture. The blood pressure (BP) was measured by OMRON’s HEM-7136 model electronic blood pressure monitor. Blood calcium (Ca<sup>2+</sup>), and blood phosphorus (P) values were measured using Colorimetric Roche kits on a Roche/Hitachi fully automated biochemical analyzer. Data collection and analysis followed. Results: Higher levels of age, systolic and diastolic blood pressures were found in the traumatic fracture group compared to the control group, whereas weight, height, and blood phosphorus did not differ significantly (P adjusting for age, systolic blood pressure, diastolic blood pressure, and blood phosphorus, binary logistic regression analysis revealed that blood calcium was a protective factor against traumatic fracture (β = -26.85, OR = 0.00, 95% CI = 0.00 -0.02, P = 0.022). Conclusion: The findings suggest that high and low blood calcium levels may serve as useful indicators in predicting the prognosis of fractures resulting from trauma.展开更多
BACKGROUND Patients with Parkinson's disease(PD)exhibit symptoms such as antecollis(AC)and camptocormia(CC).The pathology of these two conditions is unclear.Additionally,standard treatment methods have not been es...BACKGROUND Patients with Parkinson's disease(PD)exhibit symptoms such as antecollis(AC)and camptocormia(CC).The pathology of these two conditions is unclear.Additionally,standard treatment methods have not been established.The article reports the case of a 65-year-old female patient with AC and CC who was treated with central and peripheral interventions to alleviate symptoms.CASE SUMMARY We present the case of a 65-year-old female PD patient with AC and CC.The course of the disease was 5 years.She was treated with rehabilitation strategies such as sensory tricks and trunk strength training.During the inpatient period,we compared and analyzed the patient's gait,rehabilitation assessment scale score,and angles of her abnormal trunk posture in the first week,the third week,and the fifth week.The patient's stride length increased,indicating that the patient's walking ability was improved.The Unified Parkinson's Disease Scale Part Three score and CC severity score decreased.Furthermore,the score of the other scale increased.In addition,the patient showed significant improvements in AC,upper CC,and lower CC angles.CONCLUSION This case study suggested that sensory tricks and trunk strength training are beneficial and safe for patients with AC and CC.展开更多
Objective:This study aimed to estimate the incidence rate and clinical characteristics of inflammatory bowel disease(IBD)in the Chinese population,specially comparing the North and South regions.Methods:We designed a ...Objective:This study aimed to estimate the incidence rate and clinical characteristics of inflammatory bowel disease(IBD)in the Chinese population,specially comparing the North and South regions.Methods:We designed a questionnaire survey for patients diagnosed with IBD and conducted a systematic literature search in PubMed,China National Knowledge Internet,and Wanfang digital database,covering studies published between 2012 and 2022.Meta-analysis was performed to determine the overall incidence rate and prevalence of clinical manifestations of Crohn's disease(CD)and ulcerative colitis(UC)in China's Mainland.Clinical phenotypes and demographic characteristics were calculated with 95%confidence intervals(CI).A comparison between the northern and southern regions was also conducted.Results:The questionnaire survey included 440 patients,and 64 publications were included for Meta-analysis.The overall incidence rates of IBD,CD,and UC were 1.36(95%CI:0.79-2.33)per 100,000 person-years,0.23(95%CI:0.09-0.58)per 100,000 person-years,and 1.12(95%CI:0.69-1.80)per 100,000 person-years,respectively.The incidence rates of IBD,CD,and UC were all higher in southern China compared to the North.Clinical characteristics of 440 IBD patients from the questionnaire and 2,821 CD patients and 12,809 UC patients from the literature were analyzed.There were more male patients compared to female patients.CD cases in the North exhibited earlier disease diagnosis(P<0.01),more upper gastrointestinal lesions(P<0.01),and higher hospitalizations rates(P<0.01)compared to the South.UC cases in the North had higher severity(P<0.01),anemia rates(P<0.01),and weight loss(P<0.01)compared to the South.Conclusions:The incidence rates of IBD,CD,and UC were higher in southern China than in the North.Northern patients exhibited more severe symptoms compared to their southern counterparts.展开更多
Metal halide perovskite solar cells(PSCs)have shown great potential to become the next generation of photovoltaic devices due to their simple fabrication techniques,low cost,and soaring power conversion efficiency(PCE...Metal halide perovskite solar cells(PSCs)have shown great potential to become the next generation of photovoltaic devices due to their simple fabrication techniques,low cost,and soaring power conversion efficiency(PCE).However,mismatched with the quickly updated PCEs,the improvement of device stability is challenging and still remains a critical hurdle in the path to commercialization.Recently,ionic liquids(ILs)have been found to play multiple roles in obtaining efficient and stable PSCs.These ILs usually consist of large organic cations and organic or inorganic anions,which have weak electrostatic attraction and are generally liquid at around 100℃.ILs are almost non-volatile,non-flammable,with high ionic conductivity and excellent thermal and electrochemical stability.The roles of ILs in PSCs vary with their composition,that is,the types of anions and cations.In this review,we summarize the roles of anions and cations in terms of precursor solutions,additives,perovskite/charge transport layer interface engineering,and charge transport layers.This article aims to set up a structure–property-stability-performance correlations conferred by the IL in PSC and provide assistance for the anion and cation selection for improving the quality of perovskite film,optimizing interface contact,reducing defect states,and improving charge extraction and transport characteristics.Finally,the application of IL in PSCs is discussed and prospected.展开更多
Lithium-sulfur batteries(LSBs)have been regarded as one of the promising candidates for the next-generation“lithium-ion battery beyond”owing to their high energy density and due to the low cost of sulfur.However,the...Lithium-sulfur batteries(LSBs)have been regarded as one of the promising candidates for the next-generation“lithium-ion battery beyond”owing to their high energy density and due to the low cost of sulfur.However,the main obstacles encountered in the commercial implementation of LSBs are the notorious shuttle effect,retarded sulfur redox kinetics,and uncontrolled dendrite growth.Accordingly,single-atom catalysts(SACs),which have ultrahigh catalytic efficiency,tunable coordination configuration,and light weight,have shown huge potential in the field of LSBs to date.This review summarizes the recent research progress of SACs applied as multifunctional components in LSBs.The design principles and typical synthetic strategies of SACs toward effective Li–S chemistry as well as the working mechanism promoting sulfur conversion reactions,inhibiting the lithium polysulfide shuttle effect,and regulating Li+nucleation are comprehensively illustrated.Potential future directions in terms of research on SACs for the realization of commercially viable LSBs are also outlined.展开更多
We investigate the single-pulse emission variations of two pulsars,PSRs J0211+4235 and J0553+4111,observed with the Five-hundred-meter Aperture Spherical radio Telescope at the 1.25 GHz central frequency.The observati...We investigate the single-pulse emission variations of two pulsars,PSRs J0211+4235 and J0553+4111,observed with the Five-hundred-meter Aperture Spherical radio Telescope at the 1.25 GHz central frequency.The observation sessions span from 2020 December to 2021 July,with 21 and 22 observations for them respectively.The integrated pulse profile of PSR J0211+4235 shows that there is a weak pulse component following the main component,and PSR J0553+4111 displays a bimodal profile with a bridge component in the middle.PSR J0211+4235 presents significant nulling phenomenon with nulling duration lasting from 2 to 115 pulses and burst duration lasting from 2 to 113 pulses.The NF of each observation is determined to be 45%-55%.No emission greater than threeσis found in the mean integrated profile of all nulling pulses.In most cases,the pulse energy changes abruptly during the transition from null to burst,while in the transition from burst to null there are two trends:abrupt and gradual.We find that the nulling phenomenon of PSR J0211+4235 is periodic by the Fourier transform of the null and burst state.In addition,the single-pulse modulation characteristics of these two pulsars are investigated,and the distributions of modulation index,LRFS and 2DFS are analyzed with PSRSALSA.The left peak of PSR J0553+4111 has intensity modulation.Finally,the polarization properties of these two pulsars are obtained through polarization calibration,and their characteristics are analyzed.The possible physical mechanisms of these phenomena are discussed.展开更多
The inert carbon–carbon(C–C) bonds cleavage is a main bottleneck in the chemical upcycling of recalcitrant polyolefin plastics waste. Here we develop an efficient strategy to catalyze the complete cleavage of C–C b...The inert carbon–carbon(C–C) bonds cleavage is a main bottleneck in the chemical upcycling of recalcitrant polyolefin plastics waste. Here we develop an efficient strategy to catalyze the complete cleavage of C–C bonds in mixed polyolefin plastics over non-noble metal catalysts under mild conditions. The nickelbased catalyst involving Ni_(2)Al_(3) phase enables the direct transformation of mixed polyolefin plastics into natural gas, and the gas carbon yield reaches up to 89.6%. Reaction pathway investigation reveals that natural gas comes from the stepwise catalytic cleavage of C–C bonds in polypropylene, and the catalyst prefers catalytic cleavage of terminal C–C bond in the side-chain with the low energy barrier.Additionally, our developed approach is evaluated by the technical economic analysis for an economically competitive production process.展开更多
Rheumatoid arthritis imposes a huge disease burden.Existing practice guidelines do not meet the needs of integrated traditional Chinese medicine and Western medicine in the treatment of rheumatoid arthritis.We establi...Rheumatoid arthritis imposes a huge disease burden.Existing practice guidelines do not meet the needs of integrated traditional Chinese medicine and Western medicine in the treatment of rheumatoid arthritis.We established a guideline working group consists of a steering committee,a secretary group,an evidence evaluation group,a consensus group and a review group and developed a guideline following the guidance of the World Health Organization Handbook and the Chinese Medical Association.The guideline includes 35 recommendations which reached consensus by the two rounds Delphi surveys.These recommendations were formulated to address the following themes of most concern to clinician:diagnostic imaging,disease staging,traditional Chinese medicine syndromes,effectiveness and toxicity of integrated traditional Chinese medicine and Western medicine.展开更多
This paper analyzes the problems in image encryption and decryption based on chaos theory. This article introduces the application of the two-stage Logistic algorithm in image encryption and decryption, then by inform...This paper analyzes the problems in image encryption and decryption based on chaos theory. This article introduces the application of the two-stage Logistic algorithm in image encryption and decryption, then by information entropy analysis it is concluded that the security of this algorithm is higher compared with the original image;And a new image encryption and decryption algorithm based on the combination of two-stage Logistic mapping and <i>M</i> sequence is proposed. This new algorithm is very sensitive to keys;the key space is large and its security is higher than two-stage Logistic mapping of image encryption and decryption technology.展开更多
大气中CO_(2)含量的增加已对气候和环境造成巨大影响,要实现碳中和的目标,目前迫切需要开发CO_(2)高效利用技术.太阳能热化学循环CO_(2)裂解可充分利用太阳全光谱能量将CO_(2)转化为CO,从而实现太阳能到化学能的存储.进一步引入CH_(4)...大气中CO_(2)含量的增加已对气候和环境造成巨大影响,要实现碳中和的目标,目前迫切需要开发CO_(2)高效利用技术.太阳能热化学循环CO_(2)裂解可充分利用太阳全光谱能量将CO_(2)转化为CO,从而实现太阳能到化学能的存储.进一步引入CH_(4)作为氧载体的还原气体,不仅能有效降低反应温度、提高氧载体供氧能力,还能联产高质量合成气,为生产甲醇和乙酸及费托合成提供原料,达到一举多得的效果.铁基材料因其成本低、环境友好等优点受到广泛关注,但普通铁氧化物(如Fe_(3)O_(4),FeO)催化甲烷活化性能差,且受热力学限制,CO_(2)分解转化率较低.本文制备了一种FeNi合金修饰的钙钛矿复合材料为氧载体(FeNi-LFA),其在两步法太阳能热化学CO_(2)裂解反应中展现出较好的反应活性和循环稳定性.在反应温度为850℃时,CO_(2)分解速率达到381 mL g^(-1)min^(-1)(STP),转化率达到99%,氧化后材料可在恒温条件下经甲烷还原再生,合成气收率达96%以上,30次循环性能无明显下降.本文还结合高分辨透射电子显微镜(HRTEM),原位X射线衍射(XRD),原位扫描透射电镜(STEM)和57Fe穆斯堡尔谱等表征深入研究了热化学循环反应中氧载体的结构演变,并借助密度泛函理论(DFT)计算,研究其构效关系.HRTEM及EDS结果表明,FeNi-LFA中FeNi合金颗粒尺寸为20~50 nm,且合金颗粒部分嵌入到钙钛矿基体中,从而显著增强了金属-载体间相互作用.为了研究FeNi-LFA氧载体动态构造演化过程,采用XRD对氧载体反应中衍射峰变化进行研究.当FeNi-LFA暴露于CO_(2)中,FeNi合金的特征衍射峰向高角度偏移,同时,La_(2)O_(3)衍射峰减弱.钙钛矿衍射峰增强,说明氧化气氛中,FeNi合金发生Fe脱合金过程,而氧化后的铁离子能与La_(2)O_(3)快速反应生成钙钛矿氧化物.当反应气氛切换成CH_(4)后,钙钛矿衍射峰强度降低,La_(2)O_(3)信号相应增强,说明钙钛矿中铁离子脱溶析出,使材料在恒温条件下完成再生.进一步利用STEM对FeNi-LFA的结构演变中的元素迁移进行研究发现,新鲜样品中,FeNi合金与钙钛矿载体接触密切,FeNi合金周围仅有少量铁分布,在FeNi合金与氧化物载体的界面处,Fe信号强度有所下降,表明FeNi合金嵌入在富含La_(2)O_(3)的钙钛矿载体中,这与HRTEM表征结果一致.在CO_(2)裂解过程中,FeNi合金中的Fe信号明显降低,并出现金属Ni颗粒,说明Fe原子从合金中脱出.此外,在Ni颗粒表面没有出现FeO_(x)等钝化层,说明氧化后的Fe可与载体快速反应,抑制了钝化层的形成,从而有利于提高CO_(2)裂解转化率.相应^(57)Fe穆斯堡尔谱结果表明,FeNi合金中的Fe与La_(2)O_(3)反应转化为LaFeO_(3),与XRD结果一致.对反应过程进行DFT计算,发现FeNi/La_(2)O_(3)界面很容易发生CO_(2)吸附和活化,其反应活性远高于FeNi合金.同样地,氧化后形成的Ni/LaFeO_(3)(110)界面有利于CH_(4)吸附和C‒H键解离,有利于Fe离子还原和FeNi合金再生.两步法太阳能热化学CO_(2)裂解工艺经济可行性的一个关键指标是太阳能利用效率,热力学分析结果表明,即使在没有热回收的情况下,该过程的理论太阳能利用效率可达58%,当显热回收效率为90%时,太阳能利用效率可达78%.综上,本文发展了一种新型高效CO_(2)热化学裂解氧载体,实现铁在钙钛矿-合金中的定向可逆迁移,通过勒沙特列原理显著提高了CO_(2)分解转化率及反应活性,同时可产生高质量合成气.通过构建复合氧载体,实现Fe离子的原位稳定作为一种新型的氧载体设计策略,可推广应用至其他氧载体的设计开发,从而有效提高太阳能燃料生产效率.展开更多
Breviscapine,extracted from the herb Erigeron breviscapus,is widely used for the treatment of cardiovascular diseases,cerebral infarct,and stroke,but its mechanism of action remains unclear.This study established a ra...Breviscapine,extracted from the herb Erigeron breviscapus,is widely used for the treatment of cardiovascular diseases,cerebral infarct,and stroke,but its mechanism of action remains unclear.This study established a rat model of traumatic brain injury induced by controlled cortical impact,and injected 75 μg breviscapine via the right lateral ventricle.We found that breviscapine significantly improved neurobehavioral dysfunction at 6 and 9 days after injection.Meanwhile,interleukin-6 expression was markedly down-regulated following breviscapine treatment.Our results suggest that breviscapine is effective in promoting neurological behavior after traumatic brain injury and the underlying molecular mechanism may be associated with the suppression of interleukin-6.展开更多
文摘Purpose: This study aims to investigate the predictive value of blood calcium in the prognosis of traumatic fracture. Methods: A retrospective experimental design was employed, 112 cases (52 non-fracture and 60 traumatic fracture) were randomly selected. The type of fracture complies with WHO-recommended (2019) diagnostic criteria for osteoporosis combined with fracture. The blood pressure (BP) was measured by OMRON’s HEM-7136 model electronic blood pressure monitor. Blood calcium (Ca<sup>2+</sup>), and blood phosphorus (P) values were measured using Colorimetric Roche kits on a Roche/Hitachi fully automated biochemical analyzer. Data collection and analysis followed. Results: Higher levels of age, systolic and diastolic blood pressures were found in the traumatic fracture group compared to the control group, whereas weight, height, and blood phosphorus did not differ significantly (P adjusting for age, systolic blood pressure, diastolic blood pressure, and blood phosphorus, binary logistic regression analysis revealed that blood calcium was a protective factor against traumatic fracture (β = -26.85, OR = 0.00, 95% CI = 0.00 -0.02, P = 0.022). Conclusion: The findings suggest that high and low blood calcium levels may serve as useful indicators in predicting the prognosis of fractures resulting from trauma.
文摘BACKGROUND Patients with Parkinson's disease(PD)exhibit symptoms such as antecollis(AC)and camptocormia(CC).The pathology of these two conditions is unclear.Additionally,standard treatment methods have not been established.The article reports the case of a 65-year-old female patient with AC and CC who was treated with central and peripheral interventions to alleviate symptoms.CASE SUMMARY We present the case of a 65-year-old female PD patient with AC and CC.The course of the disease was 5 years.She was treated with rehabilitation strategies such as sensory tricks and trunk strength training.During the inpatient period,we compared and analyzed the patient's gait,rehabilitation assessment scale score,and angles of her abnormal trunk posture in the first week,the third week,and the fifth week.The patient's stride length increased,indicating that the patient's walking ability was improved.The Unified Parkinson's Disease Scale Part Three score and CC severity score decreased.Furthermore,the score of the other scale increased.In addition,the patient showed significant improvements in AC,upper CC,and lower CC angles.CONCLUSION This case study suggested that sensory tricks and trunk strength training are beneficial and safe for patients with AC and CC.
基金This study is approved by the Institutional Ethics Committee of The Second Affiliated Hospital of Harbin Medical University(KY2021-049).
文摘Objective:This study aimed to estimate the incidence rate and clinical characteristics of inflammatory bowel disease(IBD)in the Chinese population,specially comparing the North and South regions.Methods:We designed a questionnaire survey for patients diagnosed with IBD and conducted a systematic literature search in PubMed,China National Knowledge Internet,and Wanfang digital database,covering studies published between 2012 and 2022.Meta-analysis was performed to determine the overall incidence rate and prevalence of clinical manifestations of Crohn's disease(CD)and ulcerative colitis(UC)in China's Mainland.Clinical phenotypes and demographic characteristics were calculated with 95%confidence intervals(CI).A comparison between the northern and southern regions was also conducted.Results:The questionnaire survey included 440 patients,and 64 publications were included for Meta-analysis.The overall incidence rates of IBD,CD,and UC were 1.36(95%CI:0.79-2.33)per 100,000 person-years,0.23(95%CI:0.09-0.58)per 100,000 person-years,and 1.12(95%CI:0.69-1.80)per 100,000 person-years,respectively.The incidence rates of IBD,CD,and UC were all higher in southern China compared to the North.Clinical characteristics of 440 IBD patients from the questionnaire and 2,821 CD patients and 12,809 UC patients from the literature were analyzed.There were more male patients compared to female patients.CD cases in the North exhibited earlier disease diagnosis(P<0.01),more upper gastrointestinal lesions(P<0.01),and higher hospitalizations rates(P<0.01)compared to the South.UC cases in the North had higher severity(P<0.01),anemia rates(P<0.01),and weight loss(P<0.01)compared to the South.Conclusions:The incidence rates of IBD,CD,and UC were higher in southern China than in the North.Northern patients exhibited more severe symptoms compared to their southern counterparts.
基金financial support from the National Natural Science Foundation of China(22075094)the Fundamental Research Funds for the Central Universities。
文摘Metal halide perovskite solar cells(PSCs)have shown great potential to become the next generation of photovoltaic devices due to their simple fabrication techniques,low cost,and soaring power conversion efficiency(PCE).However,mismatched with the quickly updated PCEs,the improvement of device stability is challenging and still remains a critical hurdle in the path to commercialization.Recently,ionic liquids(ILs)have been found to play multiple roles in obtaining efficient and stable PSCs.These ILs usually consist of large organic cations and organic or inorganic anions,which have weak electrostatic attraction and are generally liquid at around 100℃.ILs are almost non-volatile,non-flammable,with high ionic conductivity and excellent thermal and electrochemical stability.The roles of ILs in PSCs vary with their composition,that is,the types of anions and cations.In this review,we summarize the roles of anions and cations in terms of precursor solutions,additives,perovskite/charge transport layer interface engineering,and charge transport layers.This article aims to set up a structure–property-stability-performance correlations conferred by the IL in PSC and provide assistance for the anion and cation selection for improving the quality of perovskite film,optimizing interface contact,reducing defect states,and improving charge extraction and transport characteristics.Finally,the application of IL in PSCs is discussed and prospected.
基金Science and Technology Innovation Program of Hunan Province,Grant/Award Number:2021RC3021Project of State Key Laboratory of Environment‐Friendly Energy Materials,Grant/Award Numbers:18ZD320304,21fksy24+2 种基金Natural Science Foundation of Hunan Province,Grant/Award Number:2021JJ40780National Natural Science Foundation of China,Grant/Award Numbers:51902346,52172239Start‐up Funding of Yangtze Region Institute(Huzhou),University of Electronic Science and Technology,Grant/Award Number:U03220102。
文摘Lithium-sulfur batteries(LSBs)have been regarded as one of the promising candidates for the next-generation“lithium-ion battery beyond”owing to their high energy density and due to the low cost of sulfur.However,the main obstacles encountered in the commercial implementation of LSBs are the notorious shuttle effect,retarded sulfur redox kinetics,and uncontrolled dendrite growth.Accordingly,single-atom catalysts(SACs),which have ultrahigh catalytic efficiency,tunable coordination configuration,and light weight,have shown huge potential in the field of LSBs to date.This review summarizes the recent research progress of SACs applied as multifunctional components in LSBs.The design principles and typical synthetic strategies of SACs toward effective Li–S chemistry as well as the working mechanism promoting sulfur conversion reactions,inhibiting the lithium polysulfide shuttle effect,and regulating Li+nucleation are comprehensively illustrated.Potential future directions in terms of research on SACs for the realization of commercially viable LSBs are also outlined.
基金financially supported by the State Key Laboratory from Structural Chemistry, Chinese Academy of Sciences (20190008)the Basic Science and Technology Research Project of Wenzhou (G20190007, ZG2017027)financial support from BUCT-WZU Joint Fund
基金supported by National Key Research and Development Program of China(2022YFC2205203)the Major Science and Technology Program of Xinjiang Uygur Autonomous Region(No.2022A03013-1)+3 种基金the National Natural Science Foundation of China(NSFC,Grant Nos.U1838109,12041304)supported by the 2021 project Xinjiang Uygur autonomous region of China for Tianshan elitesthe Youth Innovation Promotion Association of CAS under No.2023069support from the Natural Science Foundation of Shanghai(Grant No.20ZR1467600)。
文摘We investigate the single-pulse emission variations of two pulsars,PSRs J0211+4235 and J0553+4111,observed with the Five-hundred-meter Aperture Spherical radio Telescope at the 1.25 GHz central frequency.The observation sessions span from 2020 December to 2021 July,with 21 and 22 observations for them respectively.The integrated pulse profile of PSR J0211+4235 shows that there is a weak pulse component following the main component,and PSR J0553+4111 displays a bimodal profile with a bridge component in the middle.PSR J0211+4235 presents significant nulling phenomenon with nulling duration lasting from 2 to 115 pulses and burst duration lasting from 2 to 113 pulses.The NF of each observation is determined to be 45%-55%.No emission greater than threeσis found in the mean integrated profile of all nulling pulses.In most cases,the pulse energy changes abruptly during the transition from null to burst,while in the transition from burst to null there are two trends:abrupt and gradual.We find that the nulling phenomenon of PSR J0211+4235 is periodic by the Fourier transform of the null and burst state.In addition,the single-pulse modulation characteristics of these two pulsars are investigated,and the distributions of modulation index,LRFS and 2DFS are analyzed with PSRSALSA.The left peak of PSR J0553+4111 has intensity modulation.Finally,the polarization properties of these two pulsars are obtained through polarization calibration,and their characteristics are analyzed.The possible physical mechanisms of these phenomena are discussed.
基金supported by the National Natural Science Foundation of China (grant 22208339)the China Postdoctoral Science Foundation (2021M693132)+2 种基金the National Key R&D Program of China (2019YFC1905303)the Doctoral Scientific Research Foundation of Liaoning Province (2021-BS-006)the Youth Innovation Fund of Dalian Institute of Chemical Physics (DICP I202132)。
文摘The inert carbon–carbon(C–C) bonds cleavage is a main bottleneck in the chemical upcycling of recalcitrant polyolefin plastics waste. Here we develop an efficient strategy to catalyze the complete cleavage of C–C bonds in mixed polyolefin plastics over non-noble metal catalysts under mild conditions. The nickelbased catalyst involving Ni_(2)Al_(3) phase enables the direct transformation of mixed polyolefin plastics into natural gas, and the gas carbon yield reaches up to 89.6%. Reaction pathway investigation reveals that natural gas comes from the stepwise catalytic cleavage of C–C bonds in polypropylene, and the catalyst prefers catalytic cleavage of terminal C–C bond in the side-chain with the low energy barrier.Additionally, our developed approach is evaluated by the technical economic analysis for an economically competitive production process.
基金National Key Research and Development Program of China(No.2018YFC1705503).
文摘Rheumatoid arthritis imposes a huge disease burden.Existing practice guidelines do not meet the needs of integrated traditional Chinese medicine and Western medicine in the treatment of rheumatoid arthritis.We established a guideline working group consists of a steering committee,a secretary group,an evidence evaluation group,a consensus group and a review group and developed a guideline following the guidance of the World Health Organization Handbook and the Chinese Medical Association.The guideline includes 35 recommendations which reached consensus by the two rounds Delphi surveys.These recommendations were formulated to address the following themes of most concern to clinician:diagnostic imaging,disease staging,traditional Chinese medicine syndromes,effectiveness and toxicity of integrated traditional Chinese medicine and Western medicine.
文摘This paper analyzes the problems in image encryption and decryption based on chaos theory. This article introduces the application of the two-stage Logistic algorithm in image encryption and decryption, then by information entropy analysis it is concluded that the security of this algorithm is higher compared with the original image;And a new image encryption and decryption algorithm based on the combination of two-stage Logistic mapping and <i>M</i> sequence is proposed. This new algorithm is very sensitive to keys;the key space is large and its security is higher than two-stage Logistic mapping of image encryption and decryption technology.
文摘大气中CO_(2)含量的增加已对气候和环境造成巨大影响,要实现碳中和的目标,目前迫切需要开发CO_(2)高效利用技术.太阳能热化学循环CO_(2)裂解可充分利用太阳全光谱能量将CO_(2)转化为CO,从而实现太阳能到化学能的存储.进一步引入CH_(4)作为氧载体的还原气体,不仅能有效降低反应温度、提高氧载体供氧能力,还能联产高质量合成气,为生产甲醇和乙酸及费托合成提供原料,达到一举多得的效果.铁基材料因其成本低、环境友好等优点受到广泛关注,但普通铁氧化物(如Fe_(3)O_(4),FeO)催化甲烷活化性能差,且受热力学限制,CO_(2)分解转化率较低.本文制备了一种FeNi合金修饰的钙钛矿复合材料为氧载体(FeNi-LFA),其在两步法太阳能热化学CO_(2)裂解反应中展现出较好的反应活性和循环稳定性.在反应温度为850℃时,CO_(2)分解速率达到381 mL g^(-1)min^(-1)(STP),转化率达到99%,氧化后材料可在恒温条件下经甲烷还原再生,合成气收率达96%以上,30次循环性能无明显下降.本文还结合高分辨透射电子显微镜(HRTEM),原位X射线衍射(XRD),原位扫描透射电镜(STEM)和57Fe穆斯堡尔谱等表征深入研究了热化学循环反应中氧载体的结构演变,并借助密度泛函理论(DFT)计算,研究其构效关系.HRTEM及EDS结果表明,FeNi-LFA中FeNi合金颗粒尺寸为20~50 nm,且合金颗粒部分嵌入到钙钛矿基体中,从而显著增强了金属-载体间相互作用.为了研究FeNi-LFA氧载体动态构造演化过程,采用XRD对氧载体反应中衍射峰变化进行研究.当FeNi-LFA暴露于CO_(2)中,FeNi合金的特征衍射峰向高角度偏移,同时,La_(2)O_(3)衍射峰减弱.钙钛矿衍射峰增强,说明氧化气氛中,FeNi合金发生Fe脱合金过程,而氧化后的铁离子能与La_(2)O_(3)快速反应生成钙钛矿氧化物.当反应气氛切换成CH_(4)后,钙钛矿衍射峰强度降低,La_(2)O_(3)信号相应增强,说明钙钛矿中铁离子脱溶析出,使材料在恒温条件下完成再生.进一步利用STEM对FeNi-LFA的结构演变中的元素迁移进行研究发现,新鲜样品中,FeNi合金与钙钛矿载体接触密切,FeNi合金周围仅有少量铁分布,在FeNi合金与氧化物载体的界面处,Fe信号强度有所下降,表明FeNi合金嵌入在富含La_(2)O_(3)的钙钛矿载体中,这与HRTEM表征结果一致.在CO_(2)裂解过程中,FeNi合金中的Fe信号明显降低,并出现金属Ni颗粒,说明Fe原子从合金中脱出.此外,在Ni颗粒表面没有出现FeO_(x)等钝化层,说明氧化后的Fe可与载体快速反应,抑制了钝化层的形成,从而有利于提高CO_(2)裂解转化率.相应^(57)Fe穆斯堡尔谱结果表明,FeNi合金中的Fe与La_(2)O_(3)反应转化为LaFeO_(3),与XRD结果一致.对反应过程进行DFT计算,发现FeNi/La_(2)O_(3)界面很容易发生CO_(2)吸附和活化,其反应活性远高于FeNi合金.同样地,氧化后形成的Ni/LaFeO_(3)(110)界面有利于CH_(4)吸附和C‒H键解离,有利于Fe离子还原和FeNi合金再生.两步法太阳能热化学CO_(2)裂解工艺经济可行性的一个关键指标是太阳能利用效率,热力学分析结果表明,即使在没有热回收的情况下,该过程的理论太阳能利用效率可达58%,当显热回收效率为90%时,太阳能利用效率可达78%.综上,本文发展了一种新型高效CO_(2)热化学裂解氧载体,实现铁在钙钛矿-合金中的定向可逆迁移,通过勒沙特列原理显著提高了CO_(2)分解转化率及反应活性,同时可产生高质量合成气.通过构建复合氧载体,实现Fe离子的原位稳定作为一种新型的氧载体设计策略,可推广应用至其他氧载体的设计开发,从而有效提高太阳能燃料生产效率.
文摘Breviscapine,extracted from the herb Erigeron breviscapus,is widely used for the treatment of cardiovascular diseases,cerebral infarct,and stroke,but its mechanism of action remains unclear.This study established a rat model of traumatic brain injury induced by controlled cortical impact,and injected 75 μg breviscapine via the right lateral ventricle.We found that breviscapine significantly improved neurobehavioral dysfunction at 6 and 9 days after injection.Meanwhile,interleukin-6 expression was markedly down-regulated following breviscapine treatment.Our results suggest that breviscapine is effective in promoting neurological behavior after traumatic brain injury and the underlying molecular mechanism may be associated with the suppression of interleukin-6.
