371 research outputs found
Zai ji yu da xing qiang zi dui zhuang ji shang de ATLAS tan ce qi de Xigesi bo se zi de si qing zi shuai bian dao zhong yan jiu Xigesi bo se zi de ou he xing zhi
No full textPh.D.Higgs boson couplings to Standard Model vector bosons are studied in the framework of an effective-field theory approach. The analysis is based on up to 25 fb⁻¹ integrated luminosity of pp collision data at a centre-of-mass energy of 7 TeV and 8 TeV, and up to 36.5 fb⁻¹ integrated luminosity of pp collision data at a centre-of-mass energy of 13 TeV, collected by the ATLAS experiment at the Large Hadron Collider. The scaling coefficients corresponding to the Beyond Standard Model CP-even and CP-odd couplings to Z bosons are investigated. No significant deviations from the Standard Model predictions are observed. The upper limits on these Be-yond Standard Model couplings at 95% confidence level are also reported.本論文主要討論了在有效場論方法的框架下，研究希格斯玻色子與標準模型矢量玻色子的耦合。使用的是由ATLAS探測器在大型強子對撞機的質子-質子對撞實驗中所收集的數據，分別是對撞能量為7 TeV和8 TeV的總積分亮度為25 fb⁻¹的數據以及對撞能量為13 TeV的總積分亮度為36.5 fb⁻¹的數據。測量了希格斯色子的超出標準模型之外的奇宇稱和偶宇稱成分與Z矢量玻色子的耦合常數。這些超出標準模型之外的耦合常數的測量結果與標準模型的預計結果沒有顯著的偏差。此外，本論文還給出了這些耦合常數的測量結果的95%置信區間。Lu, Haonan = 在基於大型強子對撞機上的ATLAS探測器的希格斯玻色子的四輕子衰變道中研究希格斯玻色子的耦合性質 / 魯浩楠 .Thesis Ph.D. Chinese University of Hong Kong 2017.Includes bibliographical references (leaves 141-147).Abstracts also in Chinese.Title from PDF title page (viewed on …).Lu, Haonan = Zai ji yu da xing qiang zi dui zhuang ji shang de ATLAS tan ce qi de Xigesi bo se zi de si qing zi shuai bian dao zhong yan jiu Xigesi bo se zi de ou he xing zhi / Lu Haonan
A Non-Invasive Blood Pressure Estimation Method Based on Mamba-UNet and PPG Signals
Get PDFAbstract—Continuous blood pressure monitoring is of great
significance for the early diagnosis of cardiovascular diseases. To
address the limitations of current machine learning and deep
learning-based blood pressure (BP) prediction methods, which
rely on manual feature extraction and struggle to reconstruct
complete BP waveforms, this paper employs a continuous noninvasive
arterial BP detection model named Mamba-UNet based
on photoplethysmography (PPG) signals. The model deeply
integrates the selective state space model (Selective SSM) with the
U-Net architecture, achieving direct mapping from PPG signals
to arterial blood pressure (ABP) waveforms through end-to-end
modeling. In the encoder, the MambaConvBlock module captures
long-term temporal dependencies and individual vascular characteristics
of PPG signals by dynamically adjusting parameters
(Δ, B, C). The decoder employs a hybrid Mamba-convolution
structure, combining the global dynamic modeling capability of
SSM with the local feature extraction ability of convolution to
accurately reconstruct BP waveform details. The model design
balances the multi-scale feature integration advantages of U-Net
with the efficient long-sequence processing capability of Mamba.
Evaluated on the Sensors dataset (derived from MIMIC-III,
containing 1,131 ICU patient records), Mamba-UNet achieved
a mean absolute error (MAE) of 6.06 mmHg for diastolic blood
pressure (DBP) and 13.11 mmHg for systolic blood pressure
(SBP), outperforming models such as MLP, ResNet, and U-Net.
Index Terms—Arterial blood pressure (ABP), photoplethysmography
(PPG), Mamba, U-Net, non-invasive
Stimulated Raman spectroscopic imaging: data science driven innovations & applications
Get PDFStimulated Raman scattering (SRS) imaging is a chemical imaging scheme that can visualize cellular content based on intrinsic chemical bond vibrations. To resolve chemicals with overlapping Raman bands, spectroscopic SRS platforms have been developed. To date, endeavors on high-speed instrumentation have achieved spectral acquisition at the microsecond level, enabling in vivo imaging of cells and tissues. Nevertheless, due to the extremely small Raman cross-sections, the current performance of SRS is bounded by a design space that trades off speed, signal fidelity, and spectral bandwidth. The lack of tailored data mining algorithms further limits the chemical information one can extract from the spectroscopic images.
My thesis work focuses on developing computational SRS imaging approaches to break the physical tradeoffs and novel data analytical tools to decipher essential chemical information from stimulated Raman spectroscopic images. Utilizing data redundancy of spectroscopic images, we developed two compressive sensing schemes to improve the imaging speed by one order of magnitude without information loss. To break the sensitivity limit, we proposed an ultrafast spectroscopic SRS system and further integrated it with a deep neural network to synergistically achieve microsecond level imaging in the fingerprint region. To improve the chemical specificity and content levels, we implemented a sparsity-regularized spectral unmixing algorithm, realizing multiplexed imaging of up to six major metabolites in a cell. Finally, enabled by advances in low-exposure imaging and spectral unmixing, longitudinal imaging of biofuel synthesis in live cells with sophisticated chemical information is demonstrated.2022-09-24T00:00:00
Wide-field mid-infrared photothermal microscopy
Get PDFInfrared (IR) imaging has been a widely used method for chemical imaging of a variety of samples. Traditional infrared imaging method that is directly measuring IR absorption such as Fourier transform infrared (FTIR) microscopy has limited resolution due to the intrinsic long wavelength of the IR beam. Atomic force microscope-infrared (AFM-IR) spectroscopy was developed to break the IR diffraction-limited resolution of FTIR. However, it has limited speed and is only applicable for dry and flat samples. In recent years, mid-infrared photothermal (MIP) microscopy was invented to overcome the limitations of FTIR and AFM-IR. The first developed point-scanning-based MIP achieved sub-micron resolution and depth-resolved IR imaging of live biological samples. Later, wide-field-based MIP schemes were developed and dramatically improved the imaging speed of MIP. In Chapter One, this dissertation introduces the MIP development background and the MIP signal formation mechanism for general samples. In Chapters Two, Three, and Four, this dissertation further developed wide-field MIP and achieved optimal detection of three different specific types of samples by three different methodologies, which are described as follows. (1) Chapter Two, bond-selective interferometric scattering microscopy. (2) Chapter Three, back-ground suppressed high-throughput mid-infrared photothermal microscopy via pupil engineering. (3) Chapter Four, bond-selective full-field optical coherence tomography. In Chapter Five, this dissertation summarizes the work and provides an outlook of future work on video-rate bond-selective intensity diffraction tomography.
In the first methodology, we describe a bond-selective interferometric scattering microscope where the mid-IR induced photothermal signal is detected by a visible beam in a wide-field common-path interferometry configuration. Single-particle interferometric reflectance imaging sensor (SP-IRIS) has been a very promising technology for highly sensitive label-free imaging of a broad spectrum of biological nanoparticles from proteins to viruses in a high-throughput manner. Although it can reveal the specimen's size and shape information, the chemical composition is inaccessible in interferometric measurements. IR spectroscopic imaging provides chemical specificity based on inherent chemical bond vibrations of specimens but lacks the ability to image and resolve individual nanoparticles due to long IR wavelengths. Here, a bond-selective interferometric scattering microscope is achieved by detecting the mid-IR-induced photothermal modulation of a visible beam in a wide-field common-path interferometry configuration. A thin film layered substrate is utilized to reduce the reflected light and provide a reference field for the interferometric detection of the weakly scattered field. A pulsed mid-IR laser is employed to modulate the interferometric signal. Subsequent demodulation via a virtual lock-in camera offers simultaneous chemical information about tens of micro- or nano-particles. The chemical contrast arises from a minute change in the particle's scattered field as a consequence of the vibrational absorption at the target molecule. We characterize the system with sub-wavelength polymer beads and highlight biological applications by chemically imaging several microorganisms including Staphylococcus aureus, Escherichia coli, and Candida albicans. A theoretical framework is established to extend bond-selective interferometric scattering microscopy to a broad range of biological micro- and nano-particles.
In the second methodology, we demonstrate a back-ground suppressed high-throughput mid-infrared photothermal microscopy via pupil engineering. MIP microscopy has been a promising label-free chemical imaging technique for functional characterization of specimens owing to its enhanced spatial resolution and high specificity. Recently developed wide-field MIP imaging modalities have drastically improved speed and enabled high-throughput imaging of micron-scale subjects. However, the weakly scattered signal from subwavelength particles becomes indistinguishable from the shot-noise as a consequence of the strong background light, leading to limited sensitivity. Here, we demonstrate background-suppressed chemical fingerprinting at a single nanoparticle level by selectively attenuating the reflected light through pupil engineering in the collection path. Our technique provides over 3 orders of magnitude background suppression by quasi-darkfield illumination in the epi-configuration without sacrificing lateral resolution. We demonstrate 6-fold signal-to-background noise ratio improvement, allowing for simultaneous detection and discrimination of hundreds of nanoparticles across a field of view of 70 μm × 70 μm. A comprehensive theoretical framework for photothermal image formation is provided and experimentally validated with 300 and 500 nm PMMA beads. The versatility and utility of our technique are demonstrated via hyperspectral dark-field MIP imaging of S. aureus and E. coli bacteria and MIP imaging of subcellular lipid droplets inside C. albicans and cancer cells.
In the third methodology, we present a bond-selective full-field optical coherence tomography. Optical coherence tomography (OCT) is a label-free, non-invasive 3D imaging tool widely used in both biological research and clinical diagnosis. Conventional OCT modalities can only visualize specimen tomography without chemical information. Here, we report a bond-selective full-field OCT (BS-FF-OCT), in which a pulsed mid-infrared laser is used to modulate the OCT signal through the photothermal effect, achieving label-free bond-selective 3D sectioned imaging of highly scattering samples. We first demonstrate BS-FF-OCT imaging of 1 µm PMMA beads embedded in agarose gel. Next, we show 3D hyperspectral imaging of up to 75 µm of polypropylene fiber mattress from a standard surgical mask. We then demonstrate BS-FF-OCT imaging on biological samples, including cancer cell spheroids and C. elegans. Using an alternative pulse timing configuration, we finally demonstrate the capability of BS-FF-OCT on imaging a highly scattering myelinated axons region in a mouse brain tissue slice
RETRACTED ARTICLE: Effect of miR-181a-3p on osteogenic differentiation of human bone marrow-derived mesenchymal stem cells by targeting BMP10
No full textWe, the Editors and Publisher of the journal Artificial Cells, Nanomedicine, and Biotechnology, have retracted the following article:GuiLu Tao, Ping Mao, HaoNan Guan, MinFei Jiang, Tongbin Chu, CunDi Zhong & JiaZheng Liu (2019) Effect of miR-181a-3p on osteogenic differentiation of human bone marrow-derived mesenchymal stem cells by targeting BMP10. Artificial Cells, Nanomedicine, and Biotechnology, 47(1), 4159–4164, DOI: 10.1080/21691401.2019.1687494Since publication, concerns have been raised about the integrity of the data in the article. When approached for an explanation, the authors have been unable to verify their original data or answer our questions about research ethics and the informed consent process. It has also come to our attention that the full authorship list and affiliations for this manuscript were changed between submission and acceptance. As determining authorship is core to the integrity of published work and given our concerns regarding the data and ethics approvals, we are therefore retracting this article and the corresponding author listed in this publication has been informed.We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions.The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”
Test loan loss provisioning hypotheses for Chinese bank from 2011 to 2016
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The object of this dissertation is to investigate the loan loss provision behavior in Chinese bank from 2011 to 2016.This research is based on corresponding empirical literatures and 92 banks (includes: commercial and saving banks) in China. two models are used in this research, which is Stochastic frontier analysis and Generalized method of moments. X-efficiency is contained in this dissertation and the estimation variables of loan loss provision are estimated by GMM model. The consequence in this research strongly supports the pro-cyclical provision behavior in Chinese banking system. However, there is no significant variables sustain the capital management and earning management hypotheses in China banking system.
Keywords: Loan loss provision; Chinese bank; X-efficiency; GMM model; pro-cyclical provision behavio
Test loan loss provisioning hypotheses for Chinese bank from 2011 to 2016
No full textAbstract\ud
The object of this dissertation is to investigate the loan loss provision behavior in Chinese bank from 2011 to 2016.This research is based on corresponding empirical literatures and 92 banks (includes: commercial and saving banks) in China. two models are used in this research, which is Stochastic frontier analysis and Generalized method of moments. X-efficiency is contained in this dissertation and the estimation variables of loan loss provision are estimated by GMM model. The consequence in this research strongly supports the pro-cyclical provision behavior in Chinese banking system. However, there is no significant variables sustain the capital management and earning management hypotheses in China banking system.\ud
Keywords: Loan loss provision; Chinese bank; X-efficiency; GMM model; pro-cyclical provision behavio
Research on the negative externality of breeding wastewater in rural construction—Taking the large-scale breeding project of Tongnan in Chongqing as an example
No full textExperimental Investigation of Infrared Detection of Debonding in Concrete-Filled Steel Tubes via Cooling-Based Excitation
No full textDebonding in concrete-filled steel tubes (CFSTs) is a common defect that often occurs during the construction phase of CFST structures, significantly reducing their load-bearing capacity. Current methods for detecting debonding in CFSTs using infrared thermography primarily rely on heat excitation. However, applying this method during the exothermic hydration phase presents considerable challenges. This paper proposes the innovative use of spray cooling as an excitation method during the exothermic hydration phase, providing quantitative insights into the heat conduction dynamics on steel plates for infrared debonding detection in CFSTs. The effects of atomization level, excitation distance, excitation duration, and water temperature in the tank on infrared debonding detection performance were examined. The timing of the maximum temperature difference under cooling excitation was analyzed, and the heat conduction characteristics on the surface of the steel plate during the cooling process were explored. A highly efficient and stable cooling excitation method, suitable for practical engineering detection, is proposed, providing a foundation for quantitative infrared debonding detection in CFSTs. This method does not require additional energy sources, features a simple excitation process, and results in a five-times increase in temperature difference in the debonded region after excitation
Haptic Force Guided Sound Synthesis in Multisensory Virtual Reality (VR) Simulation for Rigid-Fluid Interaction
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