Search

This work details the synthesis of paramagnetic upconversion nanoparticles doped with Fe3+ in various morphologies via the thermal decomposition method, followed by comprehensive characterization of their structures, optical properties and magnetism using diverse analytical techniques. Our findings demonstrate that by precisely modulating the ratio of oleic acid to octadecene in the solvent, one can successfully obtain hexagonal nanodiscs with a consistent and well-defined morphology. Further adjustments in the oleic acid to octadecene ratio, coupled with fine-tuning of the Na+/F− ratio, led to the production of small-sized nanorods with uniform morphology. Significantly, all Fe3+-doped nanoparticles displayed pronounced paramagnetism, with magnetic susceptibility measurements at 1 T and room temperature of 0.15 emu g−1 and 0.14 emu g−1 for the nanodiscs and nanorods, respectively. To further enhance their magnetic properties, we replaced the Y-matrix with a Gd-matrix, and by fine-tuning the oleic acid/octadecene and Na+/F− ratios, we achieved nanoparticles with uniform morphology. The magnetic susceptibility was 0.82 emu g−1 at 1 T and room temperature. Simultaneously, we could control the nanoparticle size by altering the synthesis temperature. These upconversion nanostructures, characterized by both paramagnetic properties and regular morphology, represent promising dual-mode nanoprobe candidates for optical biological imaging and magnetic resonance imaging., QC 20240223

Reversible dark state transitions in fluorophores represent a limiting factor in fluorescence-based ultrasensitive spectroscopy, are a necessary basis for fluorescence-based super-resolution imaging, but may also offer additional, largely orthogonal fluorescence-based readout parameters. In this work, we analyzed the blinking kinetics of Cyanine5 (Cy5) as a bar-coding feature distinguishing Cy5 from rhodamine fluorophores having largely overlapping emission spectra. First, fluorescence correlation spectroscopy (FCS) solution measurements on mixtures of free fluorophores and fluorophore-labeled small unilamellar vesicles (SUVs) showed that Cy5 could be readily distinguished from the rhodamines by its reversible, largely excitation-driven trans-cis isomerization. This was next confirmed by transient state (TRAST) spectroscopy measurements, determining the fluorophore dark state kinetics in a more robust manner, from how the time-averaged fluorescence intensity varies upon modulation of the applied excitation light. TRAST was then combined with wide-field imaging of live cells, whereby Cy5 and rhodamine fluorophores could be distinguished on a whole cell level as well as in spatially resolved, multiplexed images of the cells. Finally, we established a microfluidic TRAST concept and showed how different mixtures of free Cy5 and rhodamine fluorophores and corresponding fluorophore-labeled SUVs could be distinguished on-the-fly when passing through a microfluidic channel. In contrast to FCS, TRAST does not rely on single-molecule detection conditions or a high time resolution and is thus broadly applicable to different biological samples. Therefore, we expect that the bar-coding concept presented in this work can offer an additional useful strategy for fluorescence-based multiplexing that can be implemented on a broad range of both stationary and moving samples., QC 20240206

The N = 34 isotope Sc-55 has been investigated using in-beam gamma-ray spectroscopy at the RIKEN Radioactive Isotope Beam Factory. Spectra from the direct (p, pn) reaction as well as indirect reaction channels have been investigated. gamma rays with energies 496(10), 570(12), 682(14), 1510(30), 1780(36), 2345(57) and 2470(50) keV have been observed. A level scheme was constructed based on gamma gamma coincidence analysis and relative intensities. The results have been compared to the level scheme already reported in literature, as well as to large-scale shell model calculations in the sd - pf model space. A new level at 1510keV, decaying directly to the ground state, has been proposed and spin-parity J(pi) = 7/2(-) was tentatively assigned. The effect of including the nu g(9/2) orbital is discussed. It can be concluded that the main low-energy properties of Sc-55 seem to be included in the original sd - pf model space., QC 20240708

XiaoLiang Wang,1,* XiaoDong Ni,1,* YanYan Wei,1 LiHua Xu,1 XiaoChen Tang,1 HaiChun Liu,2 ZiXuan Wang,3 Tao Chen,4,5 JiJun Wang,1 Qing Zhang,1 TianHong Zhang1 1Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai Engineering Research Center of Intelligent Psychological Evaluation and Intervention, Shanghai Key Laboratory of Psychotic Disorders, Shanghai, People’s Republic of China; 2Department of Automation, Shanghai Jiao Tong University, Shanghai, People’s Republic of China; 3Department of Psychology, Shanghai Xinlianxin Psychological Counseling Center, Shanghai, People’s Republic of China; 4Big Data Research Lab, University of Waterloo, Waterloo, Ontario, Canada; 5Labor and Worklife Program, Harvard University, Cambridge, MA, USA*These authors contributed equally to this workCorrespondence: TianHong Zhang; Qing Zhang, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, 600 Wanping Nan Road, Shanghai, 200030, People’s Republic of China, Tel +86-21-34773065, Fax +86-21-64387986, Email zhang_tianhong@126.com; qing.zhang@smhc.org.cnIntroduction: Despite numerous studies investigating personality disorder (PD) and childhood maltreatment (CM) characteristics in individuals with schizophrenia (SZ), there remains a scarcity of research focusing on sex differences in PD and CM within large samples of SZ patients.Methods: A total of 592 participants (257 males, 335 females) were consecutively sampled from patients diagnosed with SZ at the psychiatric and psycho-counseling clinics at Shanghai Mental Health Center. PDs were assessed using a self-reported personality diagnostic questionnaire and a structured clinical interview, while CMs were evaluated using the Chinese version of the Child Trauma Questionnaire Short Form.Results: Male patients exhibited a prominent self-reported trait of antisocial PD (t=1.972, p=0.049), while female patients demonstrated a notable emphasis on histr

Cyanine fluorophores are extensively used in fluorescence spectroscopy and imaging. Upon continuous excitation, especially at excitation conditions used in single-molecule and super-resolution experiments, photo-isomerized states of cyanines easily reach population probabilities of around 50%. Still, effects of photo-isomerization are largely ignored in such experiments. Here, we studied the photo-isomerization of the pentamethine cyanine 5 (Cy5) by two similar, yet complementary means to follow fluorophore blinking dynamics: fluorescence correlation spectroscopy (FCS) and transient-state (TRAST) excitation-modulation spectroscopy. Additionally, we combined TRAST and spectrofluorimetry (spectral-TRAST), whereby the emission spectra of Cy5 were recorded upon different rectangular pulse-train excitations. We also developed a framework for analyzing transitions between multiple emissive states in FCS and TRAST experiments, how the brightness of the different states is weighted, and what initial conditions that apply. Our FCS, TRAST, and spectral-TRAST experiments showed significant differences in dark-state relaxation amplitudes for different spectral detection ranges, which we attribute to an additional red-shifted, emissive photo-isomerized state of Cy5, not previously considered in FCS and single-molecule experiments. The photo-isomerization kinetics of this state indicate that it is formed under moderate excitation conditions, and its population and emission may thus deserve also more general consideration in fluorescence imaging and spectroscopy experiments., QC 20230307

Lanthanide-doped upconversion nanoparticles (UCNPs) have been widely exploited as nanoprobes or energy transducers in traditional as well as emerging biological applications, such as bioimaging, photodynamic ther-apy, optogenetics, gene editing. However, the breadth and depth of their utility in the biomedical areas are still not comparable to conventional luminescent probes, such as fluorescent dyes and semiconductor quantum dots. Their application is largely limited by their large size, typically > 20 nm, to ensure a sufficient luminescence brightness. In order to enhance the brightness of UCNPs without exceeding the critical size limitations for biomedical applications, we employ here a transient energy trapping effect as a nanoprobe surface passivation strategy to prevent deleterious distant energy migration in the host lattice, which is particularly prevalent in ultrasmall UCNPs and leads to luminescence quenching. We demonstrate this strategy by incorporating Tm3+ ions as energy trapping centers near the surface of sub-10 nm NaYF4: Yb, Er UCNPs and obtain an emission enhancement by almost one order of magnitude without any increment on the nanoparticle size. Our work presents a promising strategy for the preparation of ultrasmall and bright upconversion nanoprobes that are less vulnerable to surface quenching and that potentially minimize the interference with the object. This facilitates their biomedical applications as here demonstrated by unprecedented high-quality cell labeling and imaging, featured with very uniform nanoparticle distribution in the outer nuclear region., QC 20230118

Photoisomerization kinetics of the near-infrared (NIR) fluorophore Sulfo-Cyanine7 (SCy7) was studied by a combination of fluorescence correlation spectroscopy (FCS) and transient state (TRAST) excitation modulation spectroscopy. A photoisomerized state with redshifted emission was identified, with kinetics consistent with a three-state photoisomerization model. Combining TRAST excitation modulation with spectrofluorimetry (spectral-TRAST) further confirmed an excitation-induced redshift in the emission spectrum of SCy7. We show how this red-emissive photoisomerized state contributes to the blinking kinetics in different emission bands of NIR cyanine dyes, and how it can influence single-molecule, super-resolution, as well as Forster resonance energy transfer (FRET) and multicolor readouts. Since this state can also be populated at moderate excitation intensities, it can also more broadly influence fluorescence readouts, also readouts not relying on high excitation conditions. However, this additional red-emissive state and its photodynamics, as identified and characterized in this work, can also be used as a strategy to push the emission of NIR cyanine dyes further into the NIR and to enhance photosensitization of nanoparticles with absorption spectra further into the NIR. Finally, we show that the photoisomerization kinetics of SCy7 and the formation of its redshifted photoisomer depend strongly on local environmental conditions, such as viscosity, polarity, and steric constraints, which suggests the use of SCy7 and other NIR cyanine dyes as environmental sensors. Such environmental information can be monitored by TRAST, in the NIR, with low autofluorescence and scattering conditions and on a broad range of samples and experimental conditions., Funding Agencies|Swedish Foundation for Strategic Research (SSF) [ITM17-0491, RMX18-0041]; Swedish Research Council [VR 2017-04057, VR OQS 2016-06122]; Knut and Alice Wallenberg Foundation (KAW); European Union [101017180]

Lanthanide upconversion nanoparticles (UCNPs) have beenextensivelyexplored as biomarkers, energy transducers, and information carriersin wide-ranging applications in areas from healthcare and energy toinformation technology. In promoting the brightness and enrichingthe functionalities of UCNPs, core-shell structural engineeringhas been well-established as an important approach. Despite its importance,a strong limiting issue has been identified, namely, cation intermixingin the interfacial region of the synthesized core-shell nanoparticles.Currently, there still exists confusion regarding this destructivephenomenon and there is a lack of facile means to reach a delicatecontrol of it. By means of a new set of experiments, we identify andprovide in this work a comprehensive picture for the major physicalmechanism of cation intermixing occurring in synthesis of core-shellUCNPs, i.e., partial or substantial core nanoparticle dissolutionfollowed by epitaxial growth of the outer layer and ripening of theentire particle. Based on this picture, we provide an easy but effectiveapproach to tackle this issue that enables us to produce UCNPs withhighly boosted optical properties., QC 20230824

Microspheres can modulate the light field and focus the incident beam into an extremely narrow area on the back of the microsphere, so that the incident beam's full width at half maxima is smaller than the optical diffraction limit, and the focused intensity is considerably higher than the incident one. In addition, the microspheres have high numerical aperture characteristics, which can improve the collection efficiency of detection signals. Based on these benefits, microspheres offer a novel concept and method for realizing optical super-resolution imaging and fluorescence enhancement. Super-resolution imaging and fluorescence enhancement technologies based on optical microspheres are simpler, more direct, and easier to implement than traditional technologies. Their imaging and enhancement effects are comparable to those of traditional technologies. They have significant research value and application prospects in biological imaging and medical detection. Although the studies on microsphere-modulated light field to achieve fluorescence enhancement has made significant progress in recent years, review papers focusing on this topic are still limited. A systematic summary of microsphere-enhanced fluorescence and microsphere-modulated light field is critical for future studies and developments in this field. First, microsphere-based optical super-resolution imaging, including bright field super-resolution imaging and fluorescence super resolution imaging, is introduced. Subsequently, the microspheres-based fluorescence enhancement research is described, including phenomenon research, mechanism exploration, and discussion of influencing factors. Finally, the progress and applications of microsphere-based super-resolution imaging and fluorescence enhancement are summarized, and the future development challenges and trends in this field are discussed and prospected., QC 20230626

The frequency-domain (FD) method provides an alternative to the commonly used time-domain (TD) approach in characterizing the luminescence kinetics of luminophores, with its own strengths, e.g., the capability to decouple multiple lifetime components with higher reliability and accuracy. While extensively explored for characterizing luminophores with down-shifted emission, this method has not been investigated for studying nonlinear luminescent materials such as lanthanide-doped upconversion nanoparticles (UCNPs), featuring more complicated kinetics. In this work, employing a simplified rate-equation model representing a standard two-photon energy-transfer upconversion process, we thoroughly analyzed the response of the luminescence of UCNPs in the FD method. We found that the FD method can potentially obtain from a single experiment the effective decay rates of three critical energy states of the sensitizer/activator ions involved in the upconversion process. The validity of the FD method is demonstrated by experimental data, agreeing reasonably well with the results obtained by TD methods., QC 20230529

JiaYi Ye,1,* YanYan Wei,1,* JiaHui Zeng,1 YuQing Gao,1 XiaoChen Tang,1 LiHua Xu,1 YeGang Hu,1 XiaoHua Liu,1 HaiChun Liu,2 Tao Chen,3,4 ChunBo Li,1 LingYun Zeng,5,* JiJun Wang,1,6,7 TianHong Zhang1 1Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai Engineering Research Center of Intelligent Psychological Evaluation and Intervention, Shanghai Key Laboratory of Psychotic Disorders, Shanghai, 200030, People’s Republic of China; 2Department of Automation, Shanghai Jiao Tong University, Shanghai, 200240, People’s Republic of China; 3Big Data Research Lab, University of Waterloo, Ontario, Canada; 4Labor and Worklife Program, Harvard University, Cambridge, MA, USA; 5Department of Psychiatric Rehabilitation, Shenzhen Kangning Hospital, ShenZhen, GuangDong, People’s Republic of China; 6Center for Excellence in Brain Science and Intelligence Technology (CEBSIT), Chinese Academy of Science, Shanghai, People’s Republic of China; 7Institute of Psychology and Behavioral Science, Shanghai Jiao Tong University, Shanghai, People’s Republic of China*These authors contributed equally to this workCorrespondence: TianHong Zhang; JiJun Wang, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai Engineering Research Center of Intelligent Psychological Evaluation and Intervention, Shanghai Key Laboratory of Psychotic Disorders, Shanghai, 200030, People’s Republic of China, Email zhang_tianhong@126.com; jijunwang27@163.comIntroduction: Numerous studies have established the roles of inflammation and angioneurins in the pathogenesis of schizophrenia (SCZ). This study aimed to compare the serum levels of tumour necrosis factor (TNF)-α and vascular endothelial growth factor (VEGF) in patients at clinical high risk (CHR) for psychosis or SCZ at baseline and one year after treatment.Methods: A total of 289 CHR participants from the Shanghai At Risk for Psychosis Extended Program (

The electromagnetic character of the Delta I = 1 transitions connecting the 1- to 0-phonon and the 2- to 1-phonon wobbling bands should be dominated by an E2 component, due to the collective motion of the entire nuclear charge. In the present work it is shown, based on combined angular correlation and linear polarization measurements, that the mixing ratios of all analyzed connecting transitions between low-lying bands in Pr-135 interpreted as 0-, 1-, and 2-phonon wobbling bands, have absolute values smaller than one. This indicates predominant M1 magnetic character, which is incompatible with the proposed wobbling nature. All experimental observables are instead in good agreement with quasiparticle-plus-triaxial-rotor model calculations, which describe the bands as resulting from a rapid re-alignment of the total angular momentum from the short to the intermediate nuclear axis., QC 20220110

Lanthanide-doped upconversion nanoparticles (UCNPs) have rich photophysics exhibiting complex luminescence kinetics. In this work, we thoroughly investigated the luminescence response of UCNPs to excitation pulse durations. Analyzing this response opens new opportunities in optical encoding/decoding and the assignment of transitions to emission peaks and provides advantages in applications of UCNPs, e.g., for better optical sectioning and improved luminescence nanothermometry. Our work shows that monitoring the UCNP luminescence response to excitation pulse durations (while keeping the duty cycle constant) by recording the average luminescence intensity using a low-time resolution detector such as a spectrometer offers a powerful approach for significantly extending the utility of UCNPs.

Metal halide perovskite materials have been extensively explored in modern photonic devices. Photonic crystals (PCs) are periodic structures with specific optical properties, such as photonic stop bands and "slow photon " effects, which can tailor the propagation and distribution of photons in photoelectric devices. PCs have in recent years been widely explored to significantly improve the performance of perovskite luminescent materials and/or photoelectric devices. Therefore, a full understanding of the key role of PCs and a further learning of the correct use of PCs in perovskite photonic/photoelectric devices are essential for realizing the inherent potential of the superior performance of such devices. By means of this first review, we aim at offering a comprehensive framework description for PCs suitable for high-performance perovskite photoelectric devices. We start with a brief introduction to the basic aspects of PCs. Then, we summarize the influences of PCs on emission/absorption for perovskite luminescent materials. Subsequently, we systematically discuss concepts like light extraction, light trapping, slow-light effects, and structural effects of PCs for perovskite devices, with a particular emphasis on their theoretical descriptions. We argue that the marriage of perovskite materials with PCs can open up a novel frontier in photoelectric devices that potentially can spawn many exciting new fields.