746 results match your criteria: "Biomedical Imaging Center[Affiliation]"

Geometric Antibody Engineering Reveals the Spatial Factor on the Efficacy of Bispecific T Cell Engagers.

ACS Chem Biol

April 2024

College of Future Technology, Institute of Molecular Medicine, National Biomedical Imaging Center, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing 100871, China.

Bispecific antibodies (BsAbs) represent an emerging class of biologics that can recognize two different antigens or epitopes. T-cell engagers (TcEs) bind two targets in trans on the cell surface of the effector and target cell to induce proximal immune effects, opening exciting windows for immunotherapies. To date, the engineering of BsAbs has been mainly focused on tuning the molecular weight and valency.

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Breakdown of Ohm's Law in Molecular Junctions with Electrodes of Single-Layer Graphene.

J Phys Chem Lett

March 2024

Department of Materials Science and Engineering, MATEC, Guangdong Technion - Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, P. R. China.

For sufficiently low biases, Ohm's law, the cornerstone of electricity, stating that current and voltage are proportional, is satisfied at low biases for all known systems ranging from macroscopic conductors to nanojunctions. In this study, we predict theoretically and demonstrate experimentally that in single-molecule junctions fabricated with single-layer graphene as electrodes the current at low scales as the cube of , thereby invalidating Ohm's law. The absence of the ohmic regime is a direct consequence of the unique band structure of the single-layer graphene, whose vanishing density of states at the Dirac points precludes electron transfer from and to the electrodes at low biases.

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Article Synopsis
  • Spectral computed tomography (CT) is an advanced version of conventional CT that enhances imaging capabilities through dual-energy and photon-counting methods.
  • These methods offer benefits like improved image quality, better material analysis, and enhanced feature measurement compared to traditional CT.
  • Despite these advancements, spectral CT faces challenges like data and image artifacts, leading to a growing use of machine learning techniques to resolve these issues in clinical settings.
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Genetically encoded sensors for in vivo detection of neurochemicals relevant to depression.

J Neurochem

September 2024

State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China.

Depressive disorders are a common and debilitating form of mental illness with significant impacts on individuals and society. Despite the high prevalence, the underlying causes and mechanisms of depressive disorders are still poorly understood. Neurochemical systems, including serotonin, norepinephrine, and dopamine, have been implicated in the development and perpetuation of depressive symptoms.

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Transient stimulated Raman scattering spectroscopy and imaging.

Light Sci Appl

March 2024

National Biomedical Imaging Center, College of Future Technology, Peking University, Beijing, 100871, China.

Article Synopsis
  • Recent advancements in stimulated Raman scattering (SRS) improve chemical imaging, yet traditional methods face limitations in spectral resolution and sensitivity due to spectral broadening and time-energy constraints.* -
  • The newly introduced transient stimulated Raman scattering (T-SRS) utilizes quantum coherence to enable simultaneous and impulsive excitation of Raman modes, achieving higher sensitivity and the natural linewidth limit in spectral shapes.* -
  • With the use of ~150-fs laser pulses, T-SRS demonstrates enhanced performance in hyperspectral imaging of live cells and multiplexed imaging, promising significant advancements in Raman imaging applications.*
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Phase-Dislocation-Mediated High-Dimensional Fractional Acoustic-Vortex Communication.

Research (Wash D C)

December 2023

School of Computer and Electronic Information, Nanjing Normal University, Nanjing 210023, China.

With unlimited topological modes in mathematics, the fractional orbital angular momentum (FOAM) demonstrates the potential to infinitely increase the channel capacity in acoustic-vortex (AV) communications. However, the accuracy and stability of FOAM recognition are still limited by the nonorthogonality and poor anti-interference of fractional AV beams. The popular machine learning, widely used in optics based on large datasets of images, does not work in acoustics because of the huge engineering of the 2-dimensional point-by-point measurement.

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Lumos maxima - How robust fluorophores resist photobleaching?

Curr Opin Chem Biol

April 2024

College of Future Technology, Institute of Molecular Medicine, National Biomedical Imaging Center, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Science, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China; PKU-Nanjing Institute of Translational Medicine, Nanjing 211800, China. Electronic address:

Article Synopsis
  • Fluorescent dyes, used in advanced microscopy, help researchers study biomacromolecules' locations and dynamics with great detail but suffer from issues like photobleaching and photoconversion.
  • This review highlights recent developments aimed at improving the photostability of these dyes, particularly focusing on cyanine and rhodamine types.
  • The discussion includes how microenvironments and labeling methods impact dye stability and aims to encourage the creation of stronger, more reliable fluorophores for effective live cell imaging.
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Changes in Cognitive Function After Kidney Transplantation: A Longitudinal Cohort Study.

Am J Kidney Dis

July 2024

Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas; University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center, Kansas City, Kansas; Frontiers Clinical and Translational Science Institute, University of Kansas Medical Center, Kansas City, Kansas; Hoglund Biomedical Imaging Center, University of Kansas Medical Center, Kansas City, Kansas.

Rationale & Objective: Kidney disease negatively affects cognition. We assessed the effect of kidney transplantation (KT) on different cognitive domains.

Study Design: Prospective cohort study.

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Background: Osteoporosis is a bone disease related to increased bone loss and fracture-risk. The variability in bone strength is partially explained by bone mineral density (BMD), and the remainder is contributed by bone microstructure. Recently, clinical CT has emerged as a viable option for in vivo bone microstructural imaging.

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Background: Impaired brain bioenergetics is a pathological hallmark of Alzheimer's disease (AD) and is a compelling target for AD treatment. Patients with AD exhibit dysfunction in the brain creatine (Cr) system, which is integral in maintaining bioenergetic flux. Recent studies in AD mouse models suggest Cr supplementation improves brain mitochondrial function and may be protective of AD peptide pathology and cognition.

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Roles of RNA scaffolding in nanoscale Gag multimerization and selective protein sorting at HIV membranes.

Sci Adv

February 2024

Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing 100871, China.

HIV-1 Gag proteins can multimerize upon the viral genomic RNA or multiple random cellular messenger RNAs to form a virus particle or a virus-like particle, respectively. To date, whether the two types of particles form via the same Gag multimerization process has remained unclarified. Using photoactivated localization microscopy to illuminate Gag organizations and dynamics at the nanoscale, here, we showed that genomic RNA mediates Gag multimerization in a more cluster-centric, cooperative, and spatiotemporally coordinated fashion, with the ability to drive dense Gag clustering dependent on its ability to act as a long-stranded scaffold not easily attainable by cellular messenger RNAs.

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Flipover outperforms dropout in deep learning.

Vis Comput Ind Biomed Art

February 2024

Biomedical Imaging Center, Center for Biotechnology and Interdisciplinary Studies, Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.

Flipover, an enhanced dropout technique, is introduced to improve the robustness of artificial neural networks. In contrast to dropout, which involves randomly removing certain neurons and their connections, flipover randomly selects neurons and reverts their outputs using a negative multiplier during training. This approach offers stronger regularization than conventional dropout, refining model performance by (1) mitigating overfitting, matching or even exceeding the efficacy of dropout; (2) amplifying robustness to noise; and (3) enhancing resilience against adversarial attacks.

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Structure of human phagocyte NADPH oxidase in the activated state.

Nature

March 2024

State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China.

Phagocyte NADPH oxidase, a protein complex with a core made up of NOX2 and p22 subunits, is responsible for transferring electrons from intracellular NADPH to extracellular oxygen. This process generates superoxide anions that are vital for killing pathogens. The activation of phagocyte NADPH oxidase requires membrane translocation and the binding of several cytosolic factors.

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Reciprocal Copy Number Variants (CNVs) at the 16p11.2 locus confer high risk for autism spectrum disorder (ASD) and other neurodevelopmental disorders (NDDs). Morphometric MRI studies have revealed large and pervasive volumetric alterations in carriers of a 16p11.

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Real-time dual-modal photoacoustic and fluorescence small animal imaging.

Photoacoustics

April 2024

Department of Biomedical Engineering, School of Future Technology, Peking University, Beijing 100871, China.

By combining optical absorption contrast and acoustic resolution, photoacoustic imaging (PAI) has broken the barrier in depth for high-resolution optical imaging. Meanwhile, Fluorescence imaging (FLI), owing to advantages of high sensitivity and high specificity with abundant fluorescence agents and proteins, has always been playing a key role in live animal studies. Based on different optical contrast mechanisms, PAI and FLI can provide important complementary information to each other.

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Cancer treatment outcome is traditionally evaluated by tumor volume change in clinics, while tumor microvascular heterogeneity reflecting tumor response has not been fully explored due to technical limitations. We introduce a new paradigm in super-resolution ultrasound imaging, termed pattern recognition of microcirculation (PARM), which identifies both hemodynamic and morphological patterns of tumor microcirculation hidden in spatio-temporal space trajectories of microbubbles. PARM demonstrates the ability to distinguish different local blood flow velocities separated by a distance of 24 μm.

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As the emerging treatments that target grey matter pathology in Alzheimer's Disease have limited effectiveness, there is a critical need to identify new neural targets for treatments. White matter's (WM) metabolic vulnerability makes it a promising candidate for new interventions. This study examined the age and sex differences in estimates of axonal content, as well the associations of with highly prevalent modifiable health risk factors such as metabolic syndrome and adiposity.

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Making "CASES" for AI in Medicine.

BME Front

January 2024

Biomedical Imaging Center, Center for Computational Innovations, Center for Biotechnology and Interdisciplinary Studies, Department of Biomedical Engineering, School of Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.

In this perspective, "CASES" are made for AI in medicine. The CASES mean Confidence, Adaptability, Stability, Explainability, and Security of AI systems. We underline that these CASES can be addressed not only individually but also synergistically on the large model platform and using cutting-edge diffusion-type models.

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Readily releasable β cells with tight Ca-exocytosis coupling dictate biphasic glucose-stimulated insulin secretion.

Nat Metab

February 2024

New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China.

Biphasic glucose-stimulated insulin secretion (GSIS) is essential for blood glucose regulation, but a mechanistic model incorporating the recently identified islet β cell heterogeneity remains elusive. Here, we show that insulin secretion is spatially and dynamically heterogeneous across the islet. Using a zinc-based fluorophore with spinning-disc confocal microscopy, we reveal that approximately 40% of islet cells, which we call readily releasable β cells (RRβs), are responsible for 80% of insulin exocytosis events.

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Significance: Various peripheral vascular diseases (PVD) in extremities, such as arterial atherosclerosis or venous occlusion in arm or legs, are a serious global health threat. Noninvasive vascular imaging is of great value for both diagnosis and assessment of PVD.

Approach: By scanning a one-dimensional non-focusing linear array, an equivalent large two-dimensional (2D) matrix array with hundreds of thousands or more ultrasound elements is formed, thereby achieving a wide signal reception angle as well as large imaging area for three-dimensional (3D) imaging of peripheral extremities.

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Sulfonylurea receptor 2 (SUR2), intricate sensors for intracellular Mg-nucleotides.

Bioessays

March 2024

State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China.

SUR2, similar to SUR1, is a regulatory subunit of the ATP-sensitive potassium channel (KATP), which plays a key role in numerous important physiological processes and is implicated in various diseases. Recent structural studies have revealed that, like SUR1, SUR2 can undergo ligand-dependent dynamic conformational changes, transitioning between an inhibitory inward-facing conformation and an activating occluded conformation. In addition, SUR2 possesses a unique inhibitory Regulatory helix (R helix) that is absent in SUR1.

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A generalized QUCESOP method with evaluating CEST peak overlap.

NMR Biomed

May 2024

Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.

The overlapping peaks of the target chemical exchange saturation transfer (CEST) solutes and other unknown CEST solutes affect the quantification results and accuracy of the chemical exchange parameters-the fractional concentration, , exchange rate, , and transverse relaxation rate, -for the target solutes. However, to date, no method has been established for assessing the overlapping peaks. This study aimed to develop a method for quantifying the , , and values of a specific CEST solute, as well as assessing the overlap between the CEST peaks of the specific solute(s) and other unknown solutes.

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Computed tomography (CT) is one of the modalities for effective lung cancer screening, diagnosis, treatment, and prognosis. The features extracted from CT images are now used to quantify spatial and temporal variations in tumors. However, CT images obtained from various scanners with customized acquisition protocols may introduce considerable variations in texture features, even for the same patient.

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Background: Emerging evidence suggests that a number of factors can influence blood-based biomarker levels for Alzheimer's disease (AD) and Alzheimer's related dementias (ADRD). We examined the associations that demographic and clinical characteristics have with AD/ADRD blood-based biomarker levels in an observational continuation of a clinical trial cohort of older individuals with type 2 diabetes and overweight or obesity.

Methods: Participants aged 45-76 years were randomized to a 10-year Intensive Lifestyle Intervention (ILI) or a diabetes support and education (DSE) condition.

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