Publications by authors named "Siwei Xie"

Background: Gamma-ray detection plays a crucial role in the fields of biomedicine, space exploration, national defense, and security. High-precision gamma photon detection relies on scintillation crystals, which attenuate gamma rays through mechanisms such as photoelectric effect and Compton scattering. These interactions generate light signals within the scintillation crystal, which are subsequently converted into electronic signals using photodetectors, enabling accurate readout, and analysis.

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To develop and validate a novel multidimensional readout method that significantly reduces the number of readout channels (NRC) in PET detectors while maintaining high spatial and energy performance.We arranged a3×3×4SiPM array in multiple dimensions and employed row/column/layer summation with a resistor-based splitting circuit. We then applied denoising methods to enhance the peak-to-valley ratio in the decoding map, ensuring accurate crystal-position determination.

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Background: Development assistance for health (DAH) plays a vital role in supporting health programmes in low- and middle-income countries. While DAH has historically focused on infectious diseases and maternal and child health, there is a lack of comprehensive analysis of DAH trends, strategic shifts and their impact on health systems and outcomes. This study aims to provide a comprehensive review of DAH from 1990 to 2022, examining its evolution and funding allocation shifts.

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Objective: Gap balancing is a vital process during mobile-bearing unicompartmental knee arthroplasty (MB-UKA). However, this process commonly depends on the surgeon's experience and lacks specific unified standards. This study aimed to propose and evaluate a novel "measured resection" method for gap balance in MB-UKA.

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Objective: This study aims to identify the risk factors for systemic inflammatory response syndrome (SIRS) after minimally invasive percutaneous nephrolithotomy (PCNL) with a controlled irrigation pressure and to find which patients undergoing PCNL are likely to develop SIRS under the pressure-controlled condition.

Methods: A total of 303 consecutive patients who underwent first-stage PCNL in our institute between July 2016 and June 2018 were retrospectively reviewed. All the procedures were performed with an 18 F tract using an irrigation pump setting the irrigation fluid pressure at 110 mmHg and the flow rate of irrigation at 0.

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Background: Corona virus disease 2019 (COVID-19) reinfection, particularly short-term reinfection, poses challenges to the management of rheumatic diseases and may increase adverse clinical outcomes. This study aims to develop machine learning models to predict and identify the risk of short-term COVID-19 reinfection in patients with rheumatic diseases.

Methods: We developed four prediction models using explainable machine learning to assess the risk of short-term COVID-19 reinfection in 543 patients with rheumatic diseases.

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Article Synopsis
  • An organ-specific PET scanner can achieve similar sensitivity and higher spatial resolution than whole-body PET scanners by using fewer detectors, which helps to lower costs and improve image clarity.
  • The development focuses on creating high-resolution depth encoding PET detectors with better timing and fewer signal processing channels, allowing for affordable scanners tailored for specific organs.
  • The study employs a combination of silicon photomultiplier (SiPM) arrays and lutetium yttrium orthosilicate (LYSO) arrays to optimize crystal identification, measure interaction depth, and enhance coincidence timing resolutions for improved imaging accuracy.
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Article Synopsis
  • The study focuses on enhancing the performance of PET detectors by developing new algorithms to improve crystal identification and reduce edge effects.
  • The PET detectors consist of pixelated scintillator arrays read out by a SiPM array, and a novel center of gravity (COG) algorithm using six signals is tested against traditional methods that use fewer signals.
  • Results show that the new algorithm improves crystal identification at key junctions, and the raised-to-the-power (RTP) method enhances overall flood histogram quality, especially at a power of 1.5.
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  • Analysis of lipid profiles in yak ghee samples from various elevations is essential but underexplored, with this study focusing on three specific altitudes: 2986 m, 3671 m, and 4508 m.
  • The study discovered 176 lipids in total, with 147 increased and 29 decreased at different altitudes, suggesting that these lipids could be used as biomarkers for ghee differentiation based on altitude.
  • Notable findings included specific fatty acids and glycerophospholipids varying by elevation, highlighting the complexities of yak ghee's composition and its potential applications in product development.
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Article Synopsis
  • Bats have a long history and have different body functions that affect their gut bacteria.
  • A study looked at the gut bacteria of 18 bat species and found that certain types of bacteria were common in all of them.
  • The research showed that bats that eat both insects and fish have different gut bacteria compared to those that only eat insects, and their genetics related to food processing also differs.
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Biology-guided radiotherapy (BgRT) is a novel technique of external beam radiotherapy, combining positron emission tomography-computed tomography (PET-CT) with a linear accelerator (LINAC). The key innovation is to utilize PET signals from tracers in tumor tissues for real-time tracking and guiding beamlets. Compared with a traditional LINAC system, a BgRT system is more complex in hardware design, software algorithm, system integration and clinical workflow.

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Changes in soil micronutrient availability may have adverse consequences on grassland productivity, yet it’s still largely unclear how concurrent human practices, such as fertilization and mowing, affect micronutrient cycling in the plant-soil systems. Here, we measured six essential micronutrient (Fe, Mn, Cu, Zn, Co and Mo) contents in both plant pool (separated as aboveground plant parts, litter, and belowground roots) at the community level and soil pool (0−10 cm depth) after 12-year consecutive nitrogen (N) addition (0, 2, 10, and 50 g N m−2 year−1) and mowing in a typical steppe of the Mongolian Plateau. The results show that (i) medium-N (10 g m−2 year−1) and high-N (50 g m−2 year−1) addition rates significantly increased contents of soil-available Fe (+310.

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This study aimed to examine the effects of steam explosion (SE) pretreatment on the structural characteristics and immunostimulatory activity of polysaccharide from Poria cocos. Results showed that the average molecular weights of native polysaccharide (PCP) and SE-pretreated polysaccharide (SEPCP) were 18.67 and 6.

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Objective: To determine the effect of laser needle-knife on vertebroarterial morphology, fibrinogen and blood viscosity in a rabbit model of cervical spondylotic arteriopathy (CSA) and the mechanism of action involved.

Methods: A number of 40 healthy common grade rabbits were divided into four groups: normal control, model, acupuncture, and laser needle knife group. The normal control group does not establish a CSA rabbit model, and the other groups all establish a CSA rabbit model, but they are treated in different ways.

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Extracellular β-amyloid plaques and intracellular neurofibrillary tau tangles are the primary hallmarks of Alzheimer's disease. β-Amyloid pathology can be directly quantified by positron emission tomography imaging or indirectly by measuring the decrease of cerebrospinal fluid β-amyloid/β-amyloid ratio. Although these two β-amyloid biomarkers may be considered interchangeable, they sometimes show discordance, particularly in early stage of Alzheimer's disease.

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Including apolipoprotein E-ε4 (APOE-ε4) status and older age into consideration may increase the accuracy of plasma Aβ/Aβ detecting Aβ+ individuals, but the rationale behind this remains to be fully understood. Besides, both Aβ pathology and vascular diseases are related to neurodegeneration and cognitive decline, but it is still not fully understood how APOE-ε4 modulates these relationships. In this study, we examined 241 non-demented Alzheimer's Disease Neuroimaging Initiative participants to investigate the associations among age, white matter hyperintensities (WMH), hypertension, hyperlipidemia, body mass index (BMI), plasma Aβ/Aβ measured by liquid chromatography tandem mass spectrometry, and F-florbetapir Aβ PET as well as their prediction of longitudinal adjusted hippocampal volume (aHCV) and cognition in APOE-ε4 carriers and non-carriers.

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As a commonly used solution, the multi-ended readout can measure the depth-of-interaction (DOI) for positron emission tomography (PET) detectors. In the present study, the effects of the multi-ended readout design were investigated using the leading-edge discriminator (LED) triggers on the timing performance of time-of-flight (TOF) PET detectors. At the very first, the photon transmission model of the four detectors, namely, single-ended readout, dual-ended readout, side dual-ended readout, and triple-ended readout, was established in Tracepro.

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Preclinical positron emission tomography (PET) is a sensitive and quantitative molecule imaging modality widely used in characterizing the biological processes and diseases in small animals. The purpose of this study is to investigate the methods to optimize a PET detector for high-resolution preclinical imaging. The PET detector proposed in this study consists of a 28 × 28 array of LYSO crystals 0.

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Portable radiation detectors are widely used in environmental radiation detection and medical imaging due to their portability feature, high detection efficiency, and large field of view. Lutetium-yttrium oxyorthosilicate (LYSO) is a widely used scintillator in gamma radiation detection. However, the structure and the arrangement of scintillators limit the sensitivity and detection accuracy of these radiation detectors.

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We present a nonuniform multiphase (NUMP) method to construct a high-resolution time-to-digital converter (TDC) for low-cost field-programmable gate array (FPGA) devices. The NUMP method involves a system clock being passed through a series of delay elements to generate multiple clocks with different phase shifts. The phases of the rising and falling edges of all the clocks are sorted in order and the states of all the clocks are latched when a hit signal arrives.

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A practical wearable brain PET scanner capable of dynamic neuroimaging during free bodily movement will enable potential breakthrough basic neuroscience studies and help develop imaging-based neurological diagnoses and treatments. Weight, brain coverage, and sensitivity are three fundamental technical obstacles in the development of Fully Wearable High-Performance (FWHP) brain PET scanners. The purpose of this study is to investigate the feasibility of building a FWHP brain PET using a limited volume of lutetium-yttrium oxyorthosilicate (LYSO) scintillator crystals.

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This paper presented a non-uniform multiphase (NUMP) time-to-digital converter (TDC) implemented in a field-programmable gate array (FPGA) with real-time automatic temperature compensation. NUMP-TDC is a novel, low-cost, high-performance TDC that has achieved an excellent performance in Altera Cyclone V FPGA. The root mean square (RMS) for the intrinsic timing resolution was 2.

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Mitotic slippage involves cells exiting mitosis without proper chromosome segregation. Although degradation of cyclin B1 during prolonged mitotic arrest is believed to trigger mitotic slippage, its upstream regulation remains obscure. Whether mitotic slippage is caused by APC/C activity that is able to escape spindle-assembly checkpoint (SAC)-mediated inhibition, or is actively promoted by a change in SAC activity remains an outstanding issue.

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Reading out from large-scale silicon photomultiplier (SiPM) arrays is a fundamental technical obstacle blocking the application of revolutionary SiPM technologies in nuclear imaging systems. Typically, it requires using dedicated application-specific integrated circuits (ASICs) that need a long iterative process, special expertise, and tools to develop. The pico-positron emission tomography (Pico-PET) electronics system is an advanced 100-channel readout system based on 1-bit sigma-delta modulation and a field-programmable gate array (FPGA).

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