Density Functional Calculations on a Double Hydrogen-bonded Dimer

Density functional theory (DFT) calculations on a double hydrogen-bonded dimer of o-hydroxybenzoic acid were carried out at the B3LYP/6-31G* level. The optimized geometry of the dimer closely resembles that of the crystal. The calculated results show that the total energy of the dimer is much lower than the sum energies of the two monomers, and the average strength of the double hydrogen bonds is about 38.37 kJ/mol. In order to probe the origin of the interactions in the dimer, natural bond orbital analyses were performed. The thermodynamic properties of the title compound at different temperatures have also been calculated on the basis of vibrational analyses and ?GT, the change of Gibbs free energy for the aggregation from monomer to the dimmer, is 26.47 kJ/mol at 298.15 K and 0.1 MPa, implying the spontaneous process of forming the dimer. The correlation graphics of S0m, H0m and temperatures is depicted.

A Theoretical Study on the Hydrogen-bonded Dimers of HNCO Molecules

Ab initio method has been employed to investigate the hydrogenbond between two HNCO molecules. Two types of hydrogen-bondings in HNCO dimers have been found, one type is N-H…O, the other is N-H…N. The latter is a little stabler than that of the former. The stabilization energies of the two types of dimers are estimated to be 13KJ/mol-21KJ/mol.

Hydrogen-bonded organic framework modified separator for simultaneously enhancing the safety and electrochemical performance of Ni-rich lithium-ion battery

Nickel-rich layered oxide cathode(LiNi_(x)Co_(y)Mn_(1−x−y)O_(2),x>0.5,NCM)shows substantial potential for applications in longer-range electrical vehicles.However,the rapid capacity decay and serious safety concerns impede its practical viability.This work provides a hydrogen-bonded organic framework(HOF)modification strategy to simultaneously improve the electrochemical performance,thermal stability and incombustibility of separator.Melamine cyanurate(MCA),as a low-cost and reliable flame-retardant HOF,was implemented in the separator modification layer,which can prevent the battery short circuit even at a high temperature.In addition,the supermolecule properties of MCA provide unique physical and chemical microenvironment for regulating ion-transport behavior in electrolyte.The MCA coating layer enabled the nickel-rich layered oxide cathode with a high-capacity retention of 90.3%after 300 cycles at 1.0 C.Collectively,the usage of MCA in lithium-ion batteries(LIBs)affords a simple,low-cost and efficient strategy to improve the security and service life of nickel-rich layered cathodes.

High-throughput mechanistic study of highly selective hydrogen-bonded organic frameworks for electrochemical nitrate reduction to ammonia

Hydrogen-bonded organic frameworks(HOFs),an emerging porous macrocyclic materials linked by hydrogen-bond,hold potential for gas separation and storage,sensors,optical,and electrocatalysts.Here,HOF-based electrocatalysts are rationally developed for nitrates reduction to ammonia,allowing not only to regulate wastewater pollution but also to accomplish carbon-neutral ammonia(NH_(3))synthesis.We preform high-throughput computational screening of thirty-six HOFs with various metals as active sites,denoted as HOF-M1,for nitrate reduction reaction(NO_(3)RR)toward NH_(3).We have implemented a hierarchical four-step screening strategy,and ultimately,HOF-Ti1 was selected based on its exceptional catalytic activity and selectivity in the NO_(3)RR process.Through additional analysis,we discovered that the d band center of the active metal sites serves as an effective parameter for designing and predicting the performance of HOFs in NO_(3)RR.This research not only showcases the immense potential of electrocatalysis in transforming NO_(3)RR into NH_(3)but also provides researchers with a compelling incentive to undertake further experimental investigations.

Padua评分联合D-dimer对呼吸内科住院患者VTE的风险评估价值研究

目的 探讨Padua评分联合D-dimer对呼吸内科住院患者静脉血栓栓塞症(VTE)的风险评估价值。方法 纳入179例高度疑似VTE的呼吸内科住院患者。以CTPA和/或V/Q或双下(上)肢加压静脉彩超的阳性结果作为确诊VTE的金标准,采集所有纳入患者的一般资料,包括性别、年龄、现病史、吸烟史、体重指数,均行Padua评分并收集D-dimer检测值,运用受试者工作特征曲线(ROC)分析比较Padua评分、D-dimer及二者联合对呼吸内科住院患者中VTE的风险评估价值。结果 179例呼吸内科高度疑似VTE住院患者中有83例确诊,确诊率为46.4%。一般资料中VTE组和非VTE组的Padua评分和D-dimer检测相比,差异有显著统计学意义(P<0.01)。Padua评分对其预测的ROC曲线下面积(AUC)为0.784[95%CI(0.710~0.858)],最佳临界值为3.5分,≥3.5分时灵敏度为69.9%,特异度为86.5%,Youden指数为0.563;D-dimer检测对其预测的AUC为0.898[95%CI(0.852~0.943)],最佳临界值为553μg/L,≥553μg/L时灵敏度为85.5%,特异度为82.3%,Youden指数为0.678;当Padua评分≥3.5分且D-dimer≥553μg/L对其预测的AUC为0.931[95%CI(0.895~0.967)],灵敏度为86.7%,特异度为86.5%,Youden指数为0.732。Padua评分联合D-dimer对呼吸内科疑诊VTE住院患者的灵敏度、特异度、Youden指数及AUC均较Padua评分和D-dimer有显著提高,总体预测价值明显优于两种方法单独使用时。结论 Padua评分联合D-dimer对呼吸内科住院高度疑似VTE患者的风险评估的灵敏度、特异度和诊断效能方面均优于单独使用Padua评分或D-dimer检测,能够更准确的预测VTE的发生风险,有助于临床医师早期高效的筛查出VTE患者并采取相应的治疗措施。

π-Extended giant dimeric acceptor as a third component enables highly efficient ternary organic solar cells with efficiency over 19.2%

Ternary strategy with a suitable third component is a successful strategy to improve the photovoltaic performance of organic solar cells(OSCs).Very recently,Y-series based giant molecule acceptors or oligomerized acceptors have emerged as promising materials for achieving highly efficient and stable binary OSCs,while application as third component for ternary OSCs is limited.Here a novelπ-extended giant dimeric acceptor,GDF,is developed based on central Y series core fusion and rigid BDT as linker,and then incorporated into the state-of-the-art PM1:PC6 system to construct ternary OSCs.The GDF has a near planar backbone,resulting in increasedπ-conjugation,excellent crystallinity,and good electron transport capacity.When GDF is introduced into the PM1:PC6 system,it ensues in a cascade like the lowest unoccupied molecular orbitals(LUMO)energy level alignment,a complementary absorption band with PM1 and PC6,higher and balanced hole and electron mobility,slightly smaller domain size,and a higher exciton dissociation probability for PM1:PC6:GDF(1:1.1:0.1)blend film.As a consequence,the PM1:PC6:GDF(1:1.1:0.1)ternary OSC achieves a champion PCE of 19.22%,with a significantly higher open-circuit voltage and short-circuit current density,compared to 18.45%for the PM1:PC6(1:1.2)binary OSC.Our findings show that employing aπ-extended giant dimeric acceptor as a third component significantly improves the photovoltaic performance of ternary OSCs.

Catalytic Reaction Kinetics of Propylene Dimerization to 4-Methyl-1-Pentene Using Cu-K/K_(2)CO_(3) Solid Base Catalyst

The catalysis technology of propylene dimerization to form 4-methyl-1-pentene(4MP1)using a Cu-K/K_(2)CO_(3) solid base catalyst is a well-known heterogeneous catalytic reaction.In this study,the intrinsic kinetics of propylene dimerization were studied in a fixed-bed continuous reactor.Internal and external diffusion during the dimerization reaction experiments were eliminated by adjusting the flow rate of the carrier gas and the particle size of the catalyst support.Then,the concentration changes of each substance at the outlet of the catalyst bed under different residence times were investigated.Moreover,the suitable reaction kinetics equations was derived using the Langmuir Hinshelwood-Hougen-Watson kinetic model.Finally,the activation energy for each reaction involved in the dimerization reaction was calculated.The activation energies of 4MP1,branched by-products,and 1-hexene were 115.0,150.8,and 177.4 kJ/mol,respectively.The effect of process conditions on propylene dimerization with solid base catalysts was studied through kinetic model simulation.By comparing the theoretical values obtained from the simulation with the experimental results,the applicability and accuracy of the kinetic model were verified.

D-Dimer: Predictor of Postpartum Hemorrhage among Pre-Eclampsia at Kilimanjaro Christian Medical Centre

Background: Postpartum hemorrhage (PPH) is the major contributor to maternal mortality and morbidity worldwide as well as in Tanzania. Studies have shown Pre-eclampsia as a risk indicator for Postpartum hemorrhage and D-dimer tends to rise in women with pre-eclampsia. Few studies that have shown the association between D-dimer and PPH have been controversial and differ according to ethnicity and lifestyle. Hence there is no suitable reference interval for D-dimer in predicting Postpartum hemorrhage among women with pre-eclampsia. Broad Objective: This study aimed to assess the association, sensitivity, and specificity of D-dimer as a laboratory predictor of postpartum hemorrhage among women with pre-eclampsia at KCMC hospital. Methodology: This was a hospital-based analytical cross-sectional study conducted at KCMC Hospital in Northern Tanzania from September 2022 to March 2023. A total of 195 women with pre-eclampsia were included in this study. Plasma D-dimer levels were taken from women with pre-eclampsia pre-delivery. Haematocrit was compared before and after delivery, and a fall of 10% was considered as Postpartum hemorrhage together with clinical assessment of the patient. Participants were divided among those who had severe features and those who did not have severe features and were further categorized into those who had PPH and those who did not have PPH. Logistic regression was used to determine the association between D-dimer and PPH adjusting for other factors. The Receiver Operating Curve (ROC) was used to evaluate the predictive value. Results: Higher median D-dimer levels were seen among women who had PPH compared to those who had no PPH. D-dimer was seen to be associated with PPH, thus for every unit increase of µg/ml of D-dimer among women who had pre-eclampsia without severe features there was a 14% significant increase in the odds of having postpartum hemorrhage and a 45% significant increase of having postpartum hemorrhage among those who had pre-eclampsia with severe features. Furthermore, the cut-off point of a D-dimer level of 0.66 µg/ml significantly predicts postpartum hemorrhage with a sensitivity of 75% and specificity of 55%. For those who had no severe features the cut-off point was 0.53 µg/ml with a sensitivity of 95% and specificity of 53%, and for those who had severe features the cut-off point was 3.58 µg/ml with a sensitivity of 50% and specificity of 96%. Conclusion: D-dimer can be used to predict postpartum hemorrhage among pre-eclampsia, especially among those who have severe features. This shows that D-dimer has specificity in predicting PPH in women with pre-eclampsia and can be applied in clinical services to save women from maternal morbidity and mortality. Blood products such as fresh frozen plasma, platelets, and whole blood together with tranexamic acid should be readily available in women with pre-eclampsia especially those with severe features with a D-dimer level of 3.58 µg/ml and above during delivery as they are at high risk of developing PPH.

血清D-dimer、SDC-1、sTLT-1水平对多发伤合并多器官功能障碍综合征患者预后的预测价值

目的探讨血清D-二聚体(D-dimer)、多配体蛋白聚糖-1(SDC-1)和可溶性髓样细胞触发受体样转录因子-1(sTLT-1)表达水平对多发伤合并多器官功能障碍综合征(MODS)患者预后的预测价值。方法选取2022年2月至2023年2月石家庄长城中西医结合医院收治的165例急诊多发伤患者,根据是否合并MODS将其分为MODS组(66例)和无MODS组(99例),根据入院第28天MODS组患者的生存结局将多发伤合并MODS患者为死亡组(32例)和存活组(34例)。比较各组血清D-dimer、SDC-1和sTLT-1表达水平。采用多因素Logistic回归分析影响多发伤合并MODS患者预后不良的影响因素。绘制受试者工作特征(ROC)曲线分析D-dimer、SDC-1、sTLT-1对多发伤合并MODS患者预后的预测价值。结果多发伤合并MODS患者血清D-dimer、SDC-1及sTLT-1水平明显高于无MODS组,差异有统计学意义(P<0.05);多发伤合并MODS患者中死亡组血清D-dimer、SDC-1和sTLT-1水平均明显高于存活组,差异有统计学意义(P<0.05);血清D-dimer、SDC-1及sTLT-1水平升高均是多发伤合并MODS患者预后不良的危险因素(P<0.05);D-dimer、SDC-1和sTLT-1联合预测多发伤合并MODS患者预后的效能优于D-dimer、SDC-1和sTLT-1各自单独预测(P<0.05)。结论血清D-dimer、SDC-1及sTLT-1水平在多发伤合并MODS患者中明显升高,三者联合检测可评估多发伤合并MODS患者的预后。

D-dimer及hsCRP变化与主动脉夹层患者结局关系

目的探讨D-dimer及超敏C-反应蛋白(hs-CRP)变化趋势与主动脉夹层患者结局之间关系。方法收集2019年1月到2020年6月急诊科就诊并确诊为主动脉夹层的患者50例,记录其年龄、性别、结局,以及入院时和入院48 h后的D-dimer及hsCRP水平,分析其变化趋势与结局之间的关系。结果共有50患者纳入研究,其中10例患者死亡,死亡组与存活组入院时的D-dimer水平比较,差异无统计学意义(P>0.05),而入院时的死亡组hs-CRP水平、入院48 h后的D-dimer及hsCRP水平均显著高于存活组(P<0.05);死亡组患者入院48 h后的D-dimer及hsCRP水平均较入院时显著升高(P<0.05);而存活组入院48 h后的D-dimer水平较入院时明显下降(P<0.01)。结论死亡组患者的D-dimer及hsCRP均呈上升趋势,临床应注意动态监测患者的D-dimer及CRP变化,以早期分辨高危患者,及时采取相应治疗措施。

子痫前期患者血清VEGF、PLGF及血浆D-dimer水平与妊娠结局关系的研究

目的探讨子痫前期(PE)患者血清血管内皮生长因子(VEGF)、胎盘生长因子(PLGF)及血浆D-二聚体(D-dimer)水平与妊娠结局的关系。方法选取2020年8月至2022年8月宝鸡市中心医院产科收治的PE患者116例作为研究对象,根据病情严重程度分为轻度PE组(38例)和重度PE组(78例)。另选取同期住院待产正常妊娠产妇50例作为对照组。检测各组VEGF、PLGF和D-dimer水平,采用Spearman相关分析VEGF、PLGF和D-dimer与妊娠结局的相关性。结果3组年龄、体质量指数、采血孕周、孕次比较,差异均无统计学意义(P>0.05);与对照组比较,重度PE组和轻度PE组收缩压(SBP)、舒张压(DBP)、24 h尿蛋白定量均上升,且重度PE组高于轻度PE组,差异均有统计学意义(P<0.05)。与对照组比较,重度PE组和轻度PE组血清VEGF水平、血浆D-dimer水平均上升,且重度PE组高于轻度PE组,差异均有统计学意义(P<0.05)。与对照组比较,重度PE组和轻度PE组血清PLGF水平均下降,且重度PE组低于轻度PE组;差异均有统计学意义(P<0.05)。Spearman相关分析结果显示,PE患者血清VEGF水平和血浆D-dimer水平与SBP、DBP、24 h尿蛋白定量均呈正相关(P<0.05),PLGF水平与SBP、DBP、24 h尿蛋白定量均呈负相关(P<0.05)。VEGF与PE病情呈正相关(r=0.712,P=0.001),PLGF与PE病情呈负相关(r=-0.412,P=0.001),D-dimer与PE病情呈正相关(r=0.783,P=0.001)。PE患者妊娠结局包括胎盘早剥、围生儿死亡、早产、极低体质量儿、新生儿肺炎等,轻度PE组妊娠结局不良情况均少于重度PE组,差异均有统计学意义(P<0.05)。结论妊娠妇女血清VEGF和血浆D-dimer水平升高、血清PLGF水平降低与PE的发生和发展密切相关,血清VEGF、PLGF和血浆D-dimer水平可作为筛查PE及评估妊娠结局的指标。

An intravenous clarithromycin lipid emulsion with a high drug loading, H-bonding and a hydrogen-bonded ion pair complex exhibiting excellent antibacterial activity

The aim of this study was to develop an intravenous clarithromycin lipid emulsion(CLE)with good stability and excellent antibacterial activity. The CLE was prepared by the thinfilm dispersed homogenization method. The interaction between clarithromycin(CLA) and cholesteryl hemisuccinate(CHEMS) was confirmed by DSC, FT-IR and^1H NMR analysis. The interfacial drug loading, thermal sterilization, freeze–thaw stability, and in vitro and in vivo antibacterial activity were investigated systematically. DSC, FT-IR and^1H NMR spectra showed that CHEMS(CLA: CHEMS, M ratio 1:2) could interact with CLA through H-bonding and a hydrogen-bonded ion pair. The CHEMS was found necessary to maintain the stability of CLE.Ultracentrifugation showed that almost 88% CLA could be loaded into the interfacial layer.The optimized CLE formulation could withstand autoclaving at 121 °C for 10 min and remain stable after three freeze–thaw cycles. The in vitro susceptibility test revealed that the CLA–CHEMS ion-pair and CLE have similar activity to the parent drug against many different bacterial strains. The in vivo antibacterial activity showed that the ED50 of intravenous CLE was markedly lower than that of CLA solution administrated orally. CLE exhibited pronounced antibacterial activity and might be a candidate for a new nanocarrier for CLA with potential advantages over the current commercial formulation.

A Novel Hydrogen-bonded Three-dimensional Network Complex Containing Nickel

A novel complex, (H 3O) 2[Ni(2,6-pydc) 2]·2H 2O was synthesized in an aqueous solution and characterized by means of single-crystal X-ray diffraction, elemental analyses and IR spectra. The X-ray structural analysis revealed that the novel compound forms three-dimensional(3D) networks by both π-π stacking and hydrogen-bonding interactions. The crystal data for the complex are a=13.853(3) nm, b=9.6892(19) nm, c=13.732(3) nm, α=90.00°, β=115.52(3)°, γ=90.00°, Z=3, R 1=0.0786, wR 2=0.1522.

Hydrogen-bonded 1D and 2D Assemblies of Tetraiso-butyl-resorcin[4]arene in the Crystalline State

X-ray crystal structures of co-crystals involving tetra-iso-butyl-resorcin[4]arene 1 with both acetone and acetonitrile solvents were reported. The component 1?2(CH3)2CO 2 assembles such that the resorcin[4]arene adopts a C2v conformation and the acetone serves as hydrogen bond acceptors, forming a 1D hydrogen-bonded polymer. 2 (C50H68O10) crystallizes in the triclinic, space group P1 with a = 10.0440(7), b = 13.7498(9), c = 17.6374(12) ?, α = 77.726(2), β = 86.733(2), γ = 88.634(2)o, V = 2376.1(3) ?3, Dc = 1.159 g/cm3, and Z = 2. The assembly process of component 1?2CH3CN?H2O 3 yields a 2D hydrogen-bonded polymer formed by intermolecular hydrogen bonds between resorcin[4]arene and water molecules. In the case of component 3, the acetonitrile molecule serves as guest inside the bowl of resorcin[4]arene host. 3 (C48H64N2O9) crystallizes in the monoclinic, space group P2/n with a = 13.7570(18), b = 9.0961(12), c = 19.453(3) ?, β = 103.017(3)o, V = 2371.7(5) ?3, Dc = 1.138 g/cm3, and Z = 2.

One-dimensional Hydrogen-bonded Polymer Based on Tetra-iso-butyl-resorcin[4]arene and 2,6-Diacetylpyridine

The co-crystallization of tetra-iso-butyl-resorcin[4]arene 1 and 2,6-diacetyl- pyridine (Ac2py) from MeCN/CH2Cl2 yielded a multi-component complex 1?Ac2py?2H2O?0.5Me- CN 2, in which the upper rim of 1 is extended supramolecularly by way of hydrogen bonds. Complex 2 (C52H66.5N1.5O14) crystallizes in monoclinic, space group P21/m with a = 10.845(9), b = 20.805(17), c = 12.881(11) ?, β = 103.884(19)o, V = 2821(4) ?3, Dc = 1.102 g/cm3 and Z = 2. The molecular structure shows that the two adjacent double-stranded arrays as well as linear and zigzag chains generated from Ac2py and water bridging to two resorcin[4] arene molecules, respectively, facilitate self-inclusion of one-dimensional hydrogen-bonded polymer.

Hydrogen-bonded Intramolecular Charge Transfer Excited State of Dimethylaminobenzophenone using Time Dependent Density Functional Theory

Density functional theory and time-dependent density-functional theory have been used to investigate the photophysical properties and relaxation dynamics of dimethylaminobenzophe- none （DMABP） and its hydrogen-bonded DMABP-MeOH dimer. It is found that, in non- polar aprotic solvent, the transitions from So to S1 and S2 states of DMABP have both n→π and π→π＊ characters, with the locally excited feature mainly located on the C=O group and the partial CT one characterized by electron transfer mainly from the dimethylaminophenyl group to the C=O group. But when the intermolecular hydrogen bond C=O…H-O is formed, the highly polar intramolecular charge transfer character switches over to the first excited state of DMABP-MeOH dimer and the energy difference between the two low- lying electronically excited states increases. To gain insight into the relaxation dynamics of DMABP and DMABP-MeOH dimer in the excited state, the potential energy curves for con- formational relaxation are calculated. The formation of twisted intramolecular charge trans- fer state via diffusive twisting motion of the dimethylamino/dimethylaminophenyl groups is found to be the major relaxation process. In addition, the decay of the Si state of DMABP-MeOH dimer to the ground state, through nonradiative intermolecular hydrogen bond stretching vibrations, is facilitated by the formation of the hydrogen bond between DMABP and alcohols.

Two New Inclusion 1,4-Butylenediphosphonates with 3D Hydrogen-bonded Frameworks

Two new inclusion 1,4-butylenediphosphonates with three-dimensional hydrogen- bonded frameworks have been synthesized and determined by single-crystal X-ray diffraction. In compound 1, the two-dimensional cationic substructures interpenetrate into the anionic framework, and in compound 2, the cations are encapsulated in the three-dimensional framework. Crystal 1 (C14H24N2O8P2) belongs to triclinic, space group P?with a = 9.4645(2), b = 9.6490(2), c = 11.9479(3) ? = 79.7420(10), b = 73.5650(10), = 63.8420(10), V = 937.55(4) 3, Z = 2, Mr = 410.29, Dc = 1.453 g/cm3, m(MoKa) = 0.276 mm-1, F(000) = 432, the final R = 0.0465 and wR = 0.1304 for 3274 independent reflections. Crystal 2 (C18H26N2O10P2) is of monoclinic, space group P21/c with a = 9.7069(12), b = 16.227(2), c = 6.9339(9) ? b = 98.834(3), V = 1079.2(2) ?, Z = 2, Mr = 492.35, Dc = 1.515 g/cm3, m(MoKa) = 0.261 mm-1, F(000) = 516, the final R = 0.0611 and wR = 0.1162 for 1871 independent reflections.

A Hydrogen-bonded Tubular Structure of Zinc(Ⅱ) and Methyl-3-pyridylcarbamate

A zinc（Ⅱ） compound [ZnCl2（mpcm）2]（1,mpcm = methyl-3-pyridylcarbamate） was prepared by solvothermal reaction and characterized by elemental analysis,IR spectroscopy,TGA and single-crystal X-ray diffraction.The crystal is of monoclinic system,space group P21/n,C14H16ZnCl2N4O4,Mr = 440.58,a = 8.7893（7）,b = 24.978（2）,c = 9.2510（8）,β = 109.318（1）°,V = 1916.6（3）3,Z = 4,θ = 1.63～25.20°,Dc = 1.527 g/cm3,μ = 1.585 mm-1,F（000） = 896,the final R = 0.0255 and wR = 0.0654 for 3080 observed reflections with Ⅰ 〉 2σ（Ⅰ）.The zinc atom is four-coordinated by the pyridyl groups of two mpcm ligands and two chloride ions with a tetrahedral geometry.Two [ZnCl2（mpcm）2] subunits are held together by a pair of hydrogen bonds,forming a 32-membered macrocyclic dimer,which is further extended into a 3D tubular structure via hydrogen bonding.

Density functional study on chirospectra of hydrogen-bonded systems X^-(H_2O)_3(X=F,Cl,Br,I)

This paper calculates the molecular structures, infrared, Raman, circular dichroism spectra and optical rotatory powers of some hydrogen-bonded supramolecular systems as a cyclic water trimer, （H2O）3 and its pyramidal halide complexes, X- （H2O）3 （X= F, Cl, Br, I） with the gradient-corrected density functional theory method at the B3LYP/6- 311＋＋G（2d,2p） and B3LYP/Aug-cc-pVTZ levels. It finds that the complexation of halide anions with the water trimer can efficiently modulate the chirally optical behaviors. The calculated vibrational circular dichroism spectrum illuminates that the vibrational rotational strength of S（＋） （H2O）3 mostly originates from the O-H rocking modes, whereas chirality of S（-）-X-（H2O）3 （X = F, Cl, Br, I） has its important origin in the O-H stretching modes. The calculated optical rotatory power demonstrates that S（＋） （H2O）3 and S（＋）-F-（H2O）3 are positively chiral, whereas S（-）-X-（H2O）3 （X=Cl, Br, I） are negatively chiral. With the polarizable continuum model, calculated bulk solvent effect in the solvents water and carbontetrachloride and argon shows that the positive chirality of S（＋）-（H2O）3 is enhanced and the negative chirality of S（-）-X-（H2O）3 （X=Cl, Br, I） and the positive chirality of S（＋）-F-（H2O）3 are reduced with an augmentation of the solvent dielectric constant.

超声多模态评分及sFlt-1、D-Dimer对原因不明复发性流产妊娠结局的预测

目的探讨超声多模态评分及可溶性血管内皮生长因子受体-1(Soluble vascular endothelial growth factor receptor-1,sFlt-1)、D-二聚体(D-dimer,D-D)对原因不明复发性流产(Unexplained recurrent spontaneous abortion,URSA)妊娠结局的预测价值,并构建URSA不良妊娠结局的风险预测模型。方法选取2020年4月至2022年3月东莞市妇幼保健院收治的有URSA史的早孕患者136例,根据随访妊娠结局分为流产组和未流产组,比较两组超声多模态评分及sFlt-1、D-D水平,采用多因素Logistic回归分析法分析影响URSA妊娠再次流产的危险因素,建立风险预测模型并进行模型验证。结果136例孕妇保胎治疗后流产率为38.24%。流产组年龄≥35岁、饮酒史、URSA家族史、自然流产≥4次患者占比及血清sFlt-1、D-D水平均高于未流产组,孕酮及超声多模态评分均低于未流产组(P<0.05)。二元Logistic回归分析显示,自然流产≥4次、sFlt-1高水平、D-D高水平、超声多模态评分低是影响URSA妊娠再流产的独立危险因素(P<0.05)。预测模型方程:Logit(P)=-1.635+0.605×自然流产≥4次+1.332×sFlt-1+0.841×D-D+1.042×超声多模态评分;内部验证结果显示,预测模型的校正曲线与理想曲线拟合良好(Hosmer-Lemeshowχ^(2)=0.322,P=0.113)。受试者工作特征(Receiver operating characteristic,ROC)曲线结果显示,Logistic预测模型的AUC为0.933(95%CI:0.877~0.969),优于sFlt-1、D-D、超声多模态评分单项预测(P<0.05)。结论血清sFlt-1、D-D水平升高、超声多模态评分降低、自然流产≥4次是URSA妊娠再流产的高危因素,构建的风险预测模型区分度、拟合度好,能够直观准确预测URSA不良妊娠结局发生风险。