Publications by authors named "Xijie Wang"

Purpose: The 2021 WHO classification of central nervous system tumors introduced molecular criteria to stratify Grade 4 gliomas, which remain heterogeneous. This study aims to elucidate the clinical, radiological, and molecular characteristics of WHO Grade 4 gliomas, focusing on their prognostic implications and the development of a predictive model for astrocytoma IDH-mutant WHO Grade 4 (A4).

Methods: A retrospective cohort of 223 patients from Beijing Tiantan Hospital was analyzed.

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Photonic manipulation of large-capacity data with the advantages of high speed and low power consumption is a promising solution for explosive growth demands in the era of post-Moore. A well-developed lithium-niobate-on-insulator (LNOI) platform has been widely explored for high-performance electro-optic (EO) modulators to bridge electrical and optical signals. However, the photonic waveguides on the x-cut LNOI platform suffer serious polarization-mode conversion/coupling issues because of strong birefringence, making it hard to realize large-scale integration.

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Background: To investigate the joint associations between various body fat distribution parameters and high blood pressure (HBP) using the Bayesian Kernel Machine Regression (BKMR) model in school-aged children.

Methods: A diverse sample of 7 ∼ 17 years old (N = 1423; 50.25% boys) was recruited for this study.

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Conjugated diene molecules are highly reactive upon photoexcitation and can relax through multiple reaction channels that depend on the position of the double bonds and the degree of molecular rigidity. Understanding the photoinduced dynamics of these molecules is crucial for establishing general rules governing the relaxation and product formation. Here, we investigate the femtosecond time-resolved photoinduced excited-state structural dynamics of ,-1,3-cyclooctadiene, a large-flexible cyclic conjugated diene molecule, upon excitation with 200 nm using mega-electron-volt ultrafast electron diffraction and trajectory surface hopping dynamics simulations.

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Integrated miniature spectrometers have impacts in industry, agriculture, and aerospace applications due to their unique advantages in portability and energy consumption. Although existing on-chip spectrometers have achieved breakthroughs in key performance metrics, such as, a high resolution and a large bandwidth, their scanning speed and energy consumption still hinder practical applications of such devices. Here, a stationary Fourier transform spectrometer is introduced based on a Mach-Zehnder interferometer structure on thin-film lithium niobate.

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Introduction: Rapid growth has been found in the market of dietary supplements (DSs) in China. However, studies about the knowledge level, intentions, and behavior related to DS remained limited in the Chinese population. This study aimed to explore the knowledge level, perception, and practice toward DS among Chinese adults.

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Light-matter interaction at the nanoscale in magnetic alloys and heterostructures is a topic of intense research in view of potential applications in high-density magnetic recording. While the element-specific dynamics of electron spins is directly accessible to resonant x-ray pulses with femtosecond time structure, the possible element-specific atomic motion remains largely unexplored. We use ultrafast electron diffraction (UED) to probe the temporal evolution of lattice Bragg peaks of FePt nanoparticles embedded in a carbon matrix following excitation by an optical femtosecond laser pulse.

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The study shows that plant growth regulators (PGRs) have estrogenic effects, which may disrupt the normal physiological functions of endogenous estrogen in organisms. This study used electrochemical methods to investigate the electrochemical behavior and estrogenic effects of PGRs gibberellic acid (GA), ethylene (ETH), and naphthalene acetic acid (NAA) on estrogen-free human breast cancer cells (MCF-7) cells when exposed individually or in combination. The results indicate that GA, ETH, and NAA, whether used alone or in combination, exhibit estrogenic effects on MCF-7 cells.

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Background: The causal connection between morning diurnal preference and psychiatric disorders remains enigmatic. Using bidirectional two-sample Mendelian randomization (MR), we aim to explore the potential causal associations between morning diurnal preference and seven prominent psychiatric disorders.

Methods: MR is a genetic epidemiological method that leverages genetic variants as instrumental variables to infer causal associations between exposures and outcomes.

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For many chemical reactions, it remains notoriously difficult to predict and experimentally determine the rates and branching ratios between different reaction channels. This is particularly the case for reactions involving short-lived intermediates, whose observation requires ultrafast methods. The UV photochemistry of bromoform (CHBr) is among the most intensely studied photoreactions.

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Article Synopsis
  • Gliomas are "immune-desert" tumors with limited immune response, making them resistant to immunotherapies; the study investigates ways to create lymphoid structures within the glioma microenvironment to boost immunity.
  • Researchers induced the formation of these structures using TLR agonists and glioma antigens, employing various scientific techniques to understand how this promotes anti-glioma immunity.
  • Results showed that inducing these structures led to increased immune cell activity and better outcomes in glioma-bearing mice, implying that targeting the microenvironment could enhance treatment strategies for glioma in humans.
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  • This study looked at the differences in MGMTp methylation in grade 2-3 gliomas and how it affects treatment outcomes, particularly chemotherapy sensitivity and surgical resection*.
  • A total of 668 newly diagnosed glioma patients were analyzed, revealing that the extent of tumor resection (GTR vs. STR vs. PR) significantly influenced prognosis, especially for astrocytomas but less so for oligodendrogliomas*.
  • Findings showed that oligodendrogliomas had the highest MGMTp methylation levels, while astrocytomas and IDH wild-type gliomas had lower levels, indicating different responses to treatment and the importance of aggressive resection for better outcomes*.
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Ultrafast electron diffraction using MeV energy beams(MeV-UED) has enabled unprecedented scientific opportunities in the study of ultrafast structural dynamics in a variety of gas, liquid and solid state systems. Broad scientific applications usually pose different requirements for electron probe properties. Due to the complex, nonlinear and correlated nature of accelerator systems, electron beam property optimization is a time-taking process and often relies on extensive hand-tuning by experienced human operators.

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Manipulating the polarization of light at the nanoscale is key to the development of next-generation optoelectronic devices. This is typically done via waveplates using optically anisotropic crystals, with thicknesses on the order of the wavelength. Here, using a novel ultrafast electron-beam-based technique sensitive to transient near fields at THz frequencies, we observe a giant anisotropy in the linear optical response in the semimetal WTe and demonstrate that one can tune the THz polarization using a 50 nm thick film, acting as a broadband wave plate with thickness 3 orders of magnitude smaller than the wavelength.

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Article Synopsis
  • - The study demonstrates ultrafast electron diffraction (UED) techniques that utilize THz-driven bunch compression, enhancing temporal resolution for probing materials.
  • - A compression factor of about four is achieved, while time-of-arrival jitter with a pump laser is reduced by a factor of three, improving measurement accuracy.
  • - This advanced method is applied to single-crystal gold nanofilms, successfully capturing transient oscillations in THz near fields with a temporal resolution of 50 femtoseconds, which were not observable before.
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Phonon scattering in metals is one of the most fundamental processes in materials science. However, understanding such processes has remained challenging and requires detailed information on interactions between phonons and electrons. We use an ultrafast electron diffuse scattering technique to resolve the nonequilibrium phonon dynamics in femtosecond-laser-excited tungsten in both time and momentum.

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Identifying multiple rival reaction products and transient species formed during ultrafast photochemical reactions and determining their time-evolving relative populations are key steps toward understanding and predicting photochemical outcomes. Yet, most contemporary ultrafast studies struggle with clearly identifying and quantifying competing molecular structures/species among the emerging reaction products. Here, we show that mega-electronvolt ultrafast electron diffraction in combination with molecular dynamics calculations offer a powerful route to determining populations of the various isomeric products formed after UV (266 nm) excitation of the five-membered heterocyclic molecule 2(5)-thiophenone.

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Understanding the origin of electron-phonon coupling in lead halide perovskites is key to interpreting and leveraging their optical and electronic properties. Here we show that photoexcitation drives a reduction of the lead-halide-lead bond angles, a result of deformation potential coupling to low-energy optical phonons. We accomplish this by performing femtosecond-resolved, optical-pump-electron-diffraction-probe measurements to quantify the lattice reorganization occurring as a result of photoexcitation in nanocrystals of FAPbBr.

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Background: Numerous observational studies have documented an association between the circadian rhythm and the composition of the gut microbiota. However, the bidirectional causal effect of the morning chronotype on the gut microbiota is unknown.

Methods: A two-sample Mendelian randomization study was performed, using the summary statistics of the morning chronotype from the European Consortium and those of the gut microbiota from the largest available genome-wide association study meta-analysis, conducted by the MiBioGen consortium.

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Molecular ions are ubiquitous and play pivotal roles in many reactions, particularly in the context of atmospheric and interstellar chemistry. However, their structures and conformational transitions, particularly in the gas phase, are less explored than those of neutral molecules owing to experimental difficulties. A case in point is the halonium ions, whose highly reactive nature and ring strain make them short-lived intermediates that are readily attacked even by weak nucleophiles and thus challenging to isolate or capture before they undergo further reaction.

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Article Synopsis
  • The study looked at two ways to fix broken tibia and fibula bones: using an intramedullary nail (IMN) and a minimally invasive method (MIPPO).
  • 105 patients were divided into two groups to compare how well each method worked, including their recovery times and any side effects.
  • The MIPPO method turned out to have a shorter surgery time and fewer complications, but both methods helped improve ankle function in the end.
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Background: Despite the release of updated metrics for Life's Essential 8 (LE8), key indicators for assessing cardiovascular health (CVH) status, there is currently no report on their distribution among Chinese children.

Objective: This study aimed to assess the nationwide distribution of CVH in Chinese school-aged children using LE8 scores and analyze temporal changes in these scores over time.

Methods: Participants aged 7 to 19 years from 11 waves (between 1989 and 2018) of the China Health and Nutrition Survey were included in this study.

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Directly imaging structural dynamics involving hydrogen atoms by ultrafast diffraction methods is complicated by their low scattering cross sections. Here we demonstrate that megaelectronvolt ultrafast electron diffraction is sufficiently sensitive to follow hydrogen dynamics in isolated molecules. In a study of the photodissociation of gas phase ammonia, we simultaneously observe signatures of the nuclear and corresponding electronic structure changes resulting from the dissociation dynamics in the time-dependent diffraction.

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Dendrimers are a family of polymers with highly branched structure, well-defined composition, and extensive functional groups, which have attracted great attention in biomedical applications. Micelles formed by dendrimers are ideal nanocarriers for delivering anticancer agents due to the explicit study of their characteristics of particle size, charge, and biological properties such as toxicity, blood circulation time, biodistribution, and cellular internalization. Here, the classification, preparation, and structure of dendrimer micelles are reviewed, and the specific functional groups modified on the surface of dendrimers for tumor active targeting, stimuli-responsive drug release, reduced toxicity, and prolonged blood circulation time are discussed.

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