CdS量子点表面巯基酸分子排列方式的宽带和频光谱研究

巯基酸是一种常用的量子点表面配体，对量子点的光电属性和催化活性具有重要影响。用宽带和频光谱（BB-SFG）研究巯基酸分子(HS-(CH2)n-COOH，n = 2，5，10)在金膜和硫化镉（CdS）量子点表面的排列方式。结果表明：在金表面上3种自组装巯基酸单分子膜，都可以检测到与巯基和羧基相连的两个亚甲基的C-H振动和频谱峰。而在CdS量子点表面，短链的HS-(CH2)2-COOH和HS-(CH2)5-COOH处于较无序的混乱包覆状态，检测不到C-H振动和频谱峰；但长链的HS-(CH2)10-COOH在CdS量子点表面是较有序的类似反胶束状的排列，可以检测到与羧基相连的亚甲基的C-H振动谱峰。国家重点研发计划项目(2017YFA0206500,2016YFA0200702)国家自然科学基金(21327901)

CO2浓度升高、干旱胁迫和氮沉降对白羊草光 响应曲线的影响

为揭示白羊草（Ｂｏｔｈｒｉｏｃｈｌｏａ ｉｓｃｈａｅｍｕｍ （Ｌ．）Ｋｅｎｇ．）对全球气候变化的光合生理特征响应规律，采用盆栽控 制试验，研究了白羊草在不同ＣＯ２ 浓度、水分条件和施氮水平下叶片的叶绿素含量和光响应曲线特征。结果表明： 随ＣＯ２ 浓度升高和施氮量增加，白羊草叶片ＳＰＡＤ 值，最大净光合速率（Ｐｍａｘ），表观量子效率（ＡＱＥ）和光饱和点 （ＬＳＰ）均呈增加趋势；干旱胁迫降低了ＳＰＡＤ 值，Ｐｍａｘ 和ＬＳＰ。多因素方差分析表明，ＣＯ２ 浓度，水分处理和施氮 水平对ＳＰＡＤ 值，Ｐｍａｘ 和ＬＳＰ 有极显著影响，施氮水平对ＡＱＥ 有极显著影响。ＣＯ２ 浓度和水分处理对Ｐｍａｘ，ＡＱＥ 和ＬＳＰ 有显著的交互作用；ＣＯ２ 浓度和施氮水平对Ｐｍａｘ，ＡＱＥ 和光补偿点（ＬＣＰ）有极显著的交互作用；水分处理 和施氮水平对Ｐｍａｘ，ＡＱＥ 和ＬＳＰ 有极显著的交互作用。ＲＤＡ分析表明氮素是影响白羊草光合特征的最重要因 素。全球ＣＯ２ 浓度升高和氮沉降增加对干旱胁迫引起的白羊草光合速率下降有显著的缓解作用。</p

ultrasensitivedetectionofhaircortisolbasedonportableramanspectrometeranddoublelayerpapermicrodevice

Cortisol in the human hair is a clinical biomarker of long-term social-and-work-related mental stress, which is of high morbidity rate in the current modern society. This study developed a sensitive hair cortisol assay, featuring surface- enhanced Raman spectroscopy, immunoreaction, and a double-layer paper microdevice. The first layer of the paper microdevice was used to remove the hair residue in the hair extract by filtration (sample pretreatment). The second layer was used for competitive immunoreaction and detection. Standard cortisol antigen immobilized in the second layer and the free cortisol in hair extract competed to bind the spiked Raman-active cortisol monoclonal antibody solution. The hair cortisol can be quantitated by the intensity of Raman signal of monoclonal antibody bound on the paper. We found the Raman signal decreased as the cortisol concentration increases in hair samples. The relative Raman intensity measured was linearly proportional to the logarithmic value of the cortisol concentration in hair samples we measured. The detection of limit (LOD) was 1 pg/mL with the portable Raman spectrometer. The RSD of measurement was 8.38% (n=6). In addition, we used LC-MS to measure two real samples as a comparison with our method as above. The results are 0.771 and 0.153 ng/mL by LC-MS method and 0.63 and 0.247 ng/mL by the proposed method. It can be observed that the results are in same order, demonstrating the validity of the proposed method. In addition, 48 samples can be measured in a single chip. These results showed that this method is sensitive, specific, and suitable for large-scale screening of hair cortisol samples

ultrasensitivedetectionofhaircortisolbasedonportableramanspectrometeranddoublelayerpapermicrodevice

Cortisol in the human hair is a clinical biomarker of long-term social-and-work-related mental stress, which is of high morbidity rate in the current modern society. This study developed a sensitive hair cortisol assay, featuring surface- enhanced Raman spectroscopy, immunoreaction, and a double-layer paper microdevice. The first layer of the paper microdevice was used to remove the hair residue in the hair extract by filtration (sample pretreatment). The second layer was used for competitive immunoreaction and detection. Standard cortisol antigen immobilized in the second layer and the free cortisol in hair extract competed to bind the spiked Raman-active cortisol monoclonal antibody solution. The hair cortisol can be quantitated by the intensity of Raman signal of monoclonal antibody bound on the paper. We found the Raman signal decreased as the cortisol concentration increases in hair samples. The relative Raman intensity measured was linearly proportional to the logarithmic value of the cortisol concentration in hair samples we measured. The detection of limit (LOD) was 1 pg/mL with the portable Raman spectrometer. The RSD of measurement was 8.38% (n=6). In addition, we used LC-MS to measure two real samples as a comparison with our method as above. The results are 0.771 and 0.153 ng/mL by LC-MS method and 0.63 and 0.247 ng/mL by the proposed method. It can be observed that the results are in same order, demonstrating the validity of the proposed method. In addition, 48 samples can be measured in a single chip. These results showed that this method is sensitive, specific, and suitable for large-scale screening of hair cortisol samples

Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements