211 research outputs found
Multi-energy X-ray linear-array detector enabled by the side-illuminated metal halide scintillator
Conventional scintillator-based X-ray imaging typically captures the full
spectral of X-ray photons without distinguishing their energy. However, the
absence of X-ray spectral information often results in insufficient image
contrast, particularly for substances possessing similar atomic numbers and
densities. In this study, we present an innovative multi-energy X-ray
linear-array detector that leverages side-illuminated X-ray scintillation using
emerging metal halide Cs3Cu2I5. The negligible self-absorption characteristic
not only improves the scintillation output but is also beneficial for improving
the energy resolution for the side-illuminated scintillation scenarios. By
exploiting Beer's law, which governs the absorption of X-ray photons with
different energies, the incident X-ray spectral can be reconstructed by
analyzing the distribution of scintillation intensity when the scintillator is
illuminated from the side. The relative error between the reconstructed and
measured X-ray spectral was less than 5.63 %. Our method offers an additional
energy-resolving capability for X-ray linear-array detectors commonly used in
computed tomography (CT) imaging setups, surpassing the capabilities of
conventional energy-integration approaches, all without requiring extra
hardware components. A proof-of-concept multi-energy CT imaging system
featuring eight energy channels was successfully implemented. This study
presents a simple and efficient strategy for achieving multi-energy X-ray
detection and CT imaging based on emerging metal halides
Thermal properties and kinetic analysis of pyrolysis products of nicotine salts from e-cigarettes using pyrolysis-gas chromatography/mass spectrometry
Volatile organic chemicals (VOCs) released from e-cigarettes are a special source of air pollutants. In this work, we investigated the VOCs released from six nicotine salts (namely, nicotine benzoate, nicotine tartrate, nicotine citrate, nicotine malate, nicotine lactate, and nicotine levulinate) that are commonly used in e-cigarettes. The pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetric methods were used to analyze the thermogravimetric characteristics and product release behavior of different nicotine salts. Moreover, the kinetic models and thermodynamic parameters of nicotine salts during the thermal decomposition process were obtained. Thermogravimetric characteristic parameters of six nicotine salts showed significant differences. By the use of Py-GC/MS, our data showed that the pyrolysis products of nicotine salts were mainly from nicotine, acid anhydrides, carboxylic acids, and N-heterocycles, while more than 90% of the nicotine of citrate, tartrate, and malate was transferred to smoke. The result revealed that activation energies of the nicotine salts range from 21.26 to 74.10Â kJÂ mol-1, indicating that the pyrolysis of the nicotine salts is a non-spontaneous heat absorption process, and the organic acid was the key factor affecting the release of nicotine into the ambient air
Application of Permutation Entropy and Permutation Min-Entropy in Multiple Emotional States Analysis of RRI Time Series
This study’s aim was to apply permutation entropy (PE) and permutation min-entropy (PME) over an RR interval time series to quantify the changes in cardiac activity among multiple emotional states. Electrocardiogram (ECG) signals were recorded under six emotional states (neutral, happiness, sadness, anger, fear, and disgust) in 60 healthy subjects at a rate of 1000 Hz. For each emotional state, ECGs were recorded for 5 min and the RR interval time series was extracted from these ECGs. The obtained results confirm that PE and PME increase significantly during the emotional states of happiness, sadness, anger, and disgust. Both symbolic quantifiers also increase but not in a significant way for the emotional state of fear. Moreover, it is found that PME is more sensitive than PE for discriminating non-neutral from neutral emotional states.Facultad de IngenierÃ
Case report: Neglected subacute thyroiditis: a case following COVID-19 vaccination
We report a case of overlooked Subacute Thyroiditis (SAT) potentially induced by the administration of a COVID-19 vaccine. This case prompted a thorough review of the existing literature to elucidate possible mechanisms by which immune responses to the COVID-19 vaccine might precipitate thyroid damage. The primary objective is to enhance the clinical understanding and awareness of SAT among healthcare professionals. Subacute thyroiditis is a prevalent form of self-limiting thyroid disorder characterized by fever, neck pain or tenderness, and palpitations subsequent to viral infection. The development of numerous SARS-CoV-2 vaccines during the COVID-19 pandemic was intended to mitigate the spread of the virus. Nevertheless, there have been documented instances of adverse reactions arising from SARS-CoV-2 vaccines, such as the infrequent occurrence of subacute thyroiditis. While the majority of medical practitioners can discern classic subacute thyroiditis, not all cases exhibit typical characteristics, and not all systematic treatments yield positive responses. In this study, we present a rare case of subacute thyroiditis linked to the administration of the SARS-CoV-2 vaccine. A previously healthy middle-aged female developed fever and sore throat 72 h post-inoculation with the inactivated SARS-CoV-2 vaccine. Initially attributing these symptoms to a common cold, she self-administered ibuprofen, which normalized her body temperature but failed to alleviate persistent sore throat. Suspecting a laryngopharyngeal disorder, she sought treatment from an otolaryngologist. However, the pain persisted, accompanied by intermittent fever over several days. After an endocrinology consultation, despite the absence of typical neck pain, her examination revealed abnormal thyroid function, normal thyroid antibodies, heterogeneous echogenicity on thyroid ultrasonography, and elevated levels of Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP). These findings led to a consideration of the diagnosis of SAT. Initially, she was treated with non-steroidal anti-inflammatory drugs (NSAIDs) for her fever, which proved effective, but her neck pain remained uncontrolled. This suggested a poor response to NSAIDs. Consequently, steroid therapy was initiated, after which her symptoms of fever and neck pain rapidly resolved
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