Millisecond dynamics of colloidal suspension studied by X-ray photon correlation spectroscopy at the Shanghai Synchrotron Radiation Facility

X-ray photon correlation spectroscopy(XPCS)has emerged as a powerful tool for probing the nanoscale dynamics of soft condensed matter and strongly correlated materials owing to its high spatial resolution and penetration capabilities.This technique requires high brilliance and beam coherence,which are not directly available at modern synchrotron beamlines in China.To facilitate future XPCS experiments,we modified the optical setup of the newly commissioned BL10U1 USAXS beamline at the Shanghai Synchrotron Radiation Facility(SSRF).Subsequently,we performed XPCS measurements on silica suspensions in glycerol,which were opaque owing to their high concentrations.Images were collected using a high frame rate area detector.A comprehensive analysis was performed,yielding correlation functions and several key dynamic parameters.All the results were consistent with the theory of Brownian motion and demonstrated the feasibility of XPCS at SSRF.Finally,by carefully optimizing the setup and analyzing the algorithms,we achieved a time resolution of 2 ms,which enabled the characterization of millisecond dynamics in opaque systems.

Time-resolved ultra-small-angle X-ray scattering beamline(BL10U1)at SSRF

The construction of a new beamline,BL10U1,was completed at the Shanghai synchrotron radiation facility in 2020.This multipurpose beamline was designed to provide X-ray scattering techniques such as ultra-small-angle X-ray scattering(USAXS),small-angle X-ray scattering(SAXS),wide-angle X-ray scattering,and microfocus SAXS(μSAXS)for a broad user community.To realize fast time-resolved USAXS experiments,the beamline adopted an in-vacuum undulator with a total length of 1.6 m as the photon source.An in-house cryogenic-cooled double multilayer monochromator was installed to deliver a photon flux of approximately 10^(13) photons/s at a photon energy of 10 keV.The three-year successful operation of this beamline demonstrated that the monochromator operated smoothly,as expected.BL10U1 has three end stations in succession:USAXS end station,μSAXS end station,and end station for industrial applications.The minimum scattering vector q~0.0042 nm^(-1) at 10 keV can be achieved at the USAXS end station equipped with a 28 m-long and 1.8 m-diameter vacuum flight tube.At theμSAXS end station,a beam spot of less than 10×8μm was achieved for micro-SAXS experiments.In contrast,in situ experimental instruments up to 5 m high and 8 m wide can be mounted at the industrial application end station,which offers industrial scientists the opportunity to use their large industrial equipment.BL10U1 opens up a new capability to investigate phenomena such as non-equilibrium and dynamic processes of materials with a wide length scale from angstroms to micrometers with millisecond time resolution.In this paper,we also report beamline design considerations and commissioning results.

Adherence to 24-hour movement guidelines in children with mental,behavioral,and developmental disorders:Data from the 2016-2020 National Survey of Children's Health

Background:Adopting a healthy lifestyle during childhood could improve physical and mental health outcomes in adulthood and reduce relevant disease burdens.However,the lifestyles of children with mental,behavioral,and developmental disorders(MBDDs)remains under-described within the literature of public health field.This study aimed to examine adherence to 24-hour movement guidelines among children with MBDDs compared to population norms and whether these differences are affected by demographic characteristics.Methods:Data were from the 2016-2020 National Survey of Children’s Health—A national,population-based,cross-sectional study.We used the data of 119,406 children aged 6-17 years,which included 38,571 participants with at least 1 MBDD and 80,835 without.Adherence to the 24-hour movement guidelines was measured using parent-reported physical activity,screen time,and sleep duration.Results:Among children with MBDDs,20.3%,37.0%,60.7%,and 77.3%met the physical activity,screen time,sleep,and at least 1 of the 24-hour movement guidelines.These rates were lower than those in children without MBDDs(22.8%,46.2%,66.7%,and 83.4%,respectively;all p<0.001).Children with MBDDs were less likely to meet these guidelines(odds ratio(OR)=1.21,95%confidence interval(95%CI):1.13-1.30;OR=1.37,95%CI:1.29-1.45;OR=1.29,95%CI:1.21-1.37;OR=1.45,95%CI:1.35-1.56)than children without MBDDs.Children with emotional disorders had the highest odds of not meeting these guidelines(OR=1.43,95%CI:1.29-1.57;OR=1.48,95%CI:1.37-1.60;OR=1.49,95%CI:1.39-1.61;OR=1.72,95%CI:1.57-1.88)in comparison to children with other MBDDs.Among children aged12-17 years,the difference in proportion of meeting physical activity and screen time guidelines for children with vs.children without MBDD was larger than that among children aged 6-11 years.Furthermore,the above difference of meeting physical activity guidelines in ethnic minority children was smaller than that in white children.Conclusion:Children with MBDDs were less likely to meet individual or combined 24-hour movement guidelines than children without MBDDs.In educational and clinical settings,the primary focus should be on increasing physical activity and limiting screen time in children aged 12-17 years who have MBDDs;and specifically for white children who have MBDDs,increasing physical activity may help.

In situ studies on the positive and negative effects of 1,8-diiodoctane on the device performance and morphology evolution of organic solar cells

The introduction of solvent additives is one of the most common approaches for enhancing the power conversion efficiency of organic solar cells(OSCs).However,the use of solvent additives has some negative effects,and an understanding of how solvent additives affect OSCs is currently limited.In this study,we developed an in situ grazing incidence wide-angle X-ray scattering(GIWAXS)technique in the SAXS beamline(BL16 B1)at the Shanghai Synchrotron Radiation Facility,and the additive effects of1,8-diiodoctane(DIO)on the performance and morphology evolution of the PTB7-Th/PC71 BM device was investigated in depth.The results revealed that the crystal size increased with the volume ratio of DIO,and a drastic evolution of lattice space and crystal coherence length was observed during thermal annealing for the first time,to our knowledge.The discrete PC71BM molecules dissolved by DIO have an effect similar to that of the nucleating agent for PTB7-Th,boosting the crystallization of PTB7-Th,reducing phase separation,and inducing more drastic morphological evolution during thermal annealing.Our results provide a deep perspective for the mechanism of solvent additives,while also showing the significance and feasibility of the in situ GIWAXS technique we developed at BL16 B1.

Crystallization and Phase Behavior in Block Copolymer Solution:An in Situ Small Angle X-ray Scattering Study

Amphiphilic diblock copolymers self-assemble into a variety of micellar structures with diverse shapes in selective solvents. Here, we study the concentration and temperature dependence of the packing structure of spherical micelles of a polyisoprene-b-poly(2- vinylpyridine)(PI-b-P2VP) diblock copolymer in toluene using synchrotron radiation small angle X-ray scattering (SR-SAXS) and atomic force microscopy (AFM) techniques. Randomly packed spherical micelles are detected in dilute solutions, while in concentrated solutions, face-centered cubic (FCC), body-centered cubic (BCC) mixed crystal structures, and pure BCC crystal structures are observed with an increase in concentration. In situ SAXS experiments on the FCC/BCC mixed crystal structures reveal a novel FCC/BCC → BCC → Disorder → BCC phase behavior during the thermal annealing process. These results demonstrated that the BCC phase is apparently more stable than the FCC phase in the current sphere-packing system and FCC/BCC is a metastable state. The incompatibility of the PI and P2VP blocks decreases at a higher temperature and renders the variation of domain spacing.

Pre-conceptional and prenatal exposure to secondhand smoke and autism spectrum disorder:a national multi-center study in China

Background Despite extensive research evaluating the association between prenatal exposure to secondhand smoke(SHS)and the development of autism spectrum disorders(ASD),no study has investigated the association by considering the pre-conceptional period.This study aimed to investigate the associations of pre-conceptional and prenatal SHS exposure and the development of ASD among toddlers.Methods In this cross-sectional study,parents of 6049 toddlers aged 16–30 months were recruited from 7 tertiary hospitals,21 communities,and 7 kindergartens located in seven cities in six provinces from five geographical regions of China.We analyzed the associations of SHS exposure and the odds of ASD among toddlers in different exposure windows(pre-conceptional and/or prenatal periods).Data were analyzed from November 2021 to January 2022.Results Among the 6049 toddlers included in the analysis[22.7(4.1)months;44.8%girls],71 were identified and diagnosed with ASD.Compared with the unexposed toddlers,toddlers with pre-conceptional SHS exposure had higher odds of ASD(OR 2.30,95%CI 1.36–3.84),while we observed a non-significantly positive association regarding prenatal SHS exposure.When considering both pre-conceptional and prenatal periods,toddlers who were continuously exposed to SHS during these two periods had higher odds than those without SHS exposure(OR 2.32,95%CI 1.24–4.14).Conclusion We reported positive SHS–ASD associations when exposed during the pre-conceptional period and continuously exposed during pre-conceptional and prenatal periods,emphasizing the critical window of pre-conception for targeted intervention on smoking.

Brain structure underlying the empathizing–systemizing difference in children with autism spectrum disorder

Background Behavioral research has shown that children with autism spectrum disorder(ASD)have a higher empathizing–systemizing difference(D score)than normal children.However,there is no research about the neuroanatomical mechanisms of the empathizing–systemizing difference in children with ASD.Methods Participants comprised 41 children with ASD and 39 typically developing(TD)children aged 6‒12 years.Empathizing–systemizing difference was estimated using the D score from the Chinese version of Children’s Empathy Quotient and Systemizing Quotient.We quantified brain morphometry,including global and regional brain volumes and surface-based cortical measures(cortical thickness,surface area,and gyrification)via structural magnetic resonance imaging.Results We found that the D score was significantly negatively associated with amygdala gray matter volume[β=−0.16;95%confidence interval(CI):−0.30,−0.02;P value=0.030]in children with ASD.There was a significantly negative association between D score and gyrification in the left lateral occipital cortex(LOC)in children with ASD(B=−0.10;SE=0.03;cluster-wise P value=0.006)and a significantly positive association between D score and gyrification in the right fusiform in TD children(B=0.10;SE=0.03;cluster-wise P value=0.022).Moderation analyses demonstrated significant interactions between D score and diagnosed group in amygdala gray matter volume(β=0.19;95%CI 0.04,0.35;P value=0.013)and left LOC gyrification(β=0.11;95%CI 0.05,0.17;P value=0.001)but not in right fusiform gyrification(β=0.08;95%CI−0.02,0.17;P value=0.105).Conclusions Neuroanatomical variation in amygdala volume and gyrification of LOC could be potential biomarkers for the empathizing–systemizing difference in children with ASD but not in TD children.Large-scale neuroimaging studies are necessary to test the replicability of our findings.

Violence-related behaviors among adolescents and its association with cognitive emotion regulation strategies

Background:Adolescent violence is now regarded as a major public health concern.Despite growing interest in psychographic risk factors for violent behavior,few studies have explored the role of strategies to regulate cognitive emotion in adolescents.This study aimed to investigate the prevalence of adolescent violence behaviors and to identify the relationship between specific strategies to regulate cognitive emotion and forms of violent behavior.Methods:We cross-sectionally surveyed 3315 students in grades 7 to 10 using anonymous,self-reporting questionnaires to examine strategies to regulate cognitive emotion and violence-related behaviors in young adolescents.A logistic regression model was used to identify the relationship between specific violent behaviors and strategies to regulate cognitive emotion.Results:The most commonly reported type of violent behavior was verbal attack(48.6%),while 7.1%of students were involved in fi ghts and 2.4%had been injured in fights.Boys were involved in all forms of violent behavior studied,and did so significantly more often than girls(P<0.05).Logistic regression revealed that six cognitive emotion strategies(self-blame,rumination,planning,reappraisal,catastrophisizing,and blaming others)were associated with violent behaviors,of which catastrophisizing was the most significant factor of all violent behaviors examined that were infl uenced by this strategy.Conclusions:Violence-related behaviors,especially verbal attacks,were common among adolescents.Several cognitive emotion regulation strategies were positively associated with specific violent behaviors,but catastrophisizing was strongly related to all forms of violent behavior.Thus,programs targeting adolescent violence must address this and other maladaptive cognitive emotion regulation strategies.

Deformation Temperature and Lamellar Thickness Dependency of FormⅠto Form Ⅲ Phase Transition in Syndiotactic Polypropylene during Tensile Stretching

Phase transition from form Ⅰ to form Ⅲ in syndiotactic polypropylene crystallized at different conditions during tensile deformation at different temperatures was investigated by using in situ synchrotron wide angle X-ray diffraction technique. In all cases, the occurrence of this phase transition was observed. The onset strain of this transition was found to be crystalline thickness decided by crystallization temperature and drawing temperature dependent. The effect of drawing temperature on this phase transition is understood by the changes in mechanical properties with temperature. Moreover, crystalline thickness dependency of the phase transition reveals that this form Ⅰ to from Ⅲ phase transition occurs first in those lamellae with their normal along the stretching direction which have not experienced stress induced melting and recrystallization.