Phantom study of a self-shielded X-ray bone age assessment instrument against scattered radiation in children.

Hand-wrist radiography is the most common and accurate method for evaluating children's bone age. To reduce the scattered radiation of radiosensitive organs in bone age assessment, we designed a small X-ray instrument with radioprotection function by adding metal enclosure for X-ray shielding. We used a phantom operator to compare the scattered radiation doses received by sensitive organs under three different protection scenarios (proposed instrument, radiation personal protective equipment, no protection). The proposed instrument showed greater reduction in the mean dose of a single exposure compared with radiation personal protective equipment especially on the left side which was proximal to the X-ray machine (≥80.0% in eye and thyroid, ≥99.9% in breast and gonad). The proposed instrument provides a new pathway towards more convenient and efficient radioprotection.

A phantom study of a protective trolley for neonatal radiographic imaging: new equipment to protect the operator from scatter radiation.

Chest radiography is commonly performed as a diagnostic tool of neonatal diseases. Contact-based radiation personal protective equipment (RPPE) has been widely used for radiation protection, but it does not provide full body protection and it is often shared between users, which has become a major concern during the coronavirus disease 2019 (COVID-19) pandemic. To address these issues, we developed a novel trolley to protect radiographers against X-ray radiation by reducing scatter radiation during neonatal radiographic examinations. We measured the scatter radiation doses from a standard neonatal chest radiograph to the radiosensitive organs using a phantom operator in three protection scenarios (trolley, radiation personal protective equipment [RPPE], no protection) and at three distances. The results showed that the scatter radiation surface doses were significantly reduced when using the trolley compared with RPPE and with no protection at a short distance (P<0.05 for both scenarios in all radiosensitive organs). The novel protective trolley provides a non-contact protective tool for radiographers against the hazard of scatter radiation during neonatal radiography examinations.

Efficacy assessment of superficial temporal artery-middle cerebral artery bypass surgery in treating moyamoya disease from a hemodynamic perspective: a pilot study using computational modeling and perfusion imaging.

BACKGROUND: Superficial temporal artery-middle cerebral artery (STA-MCA) bypass is a common surgery in treating moyamoya disease (MMD) with occluded MCA. Computational fluid dynamics (CFD) simulation might provide a simple, non-invasive, and low-cost tool to evaluate the efficacy of STA-MCA surgery. AIM: We aim to quantitatively investigate the treatment efficacy of STA-MCA surgery in improving the blood flow of MMD patients using CFD simulation. METHODS: This retrospective study included 11 MMD patients with occlusion around proximal MCA who underwent STA-MCA bypass surgery. CFD simulation was performed using patient-specific blood pressure and postoperative artery geometry. The volumetric flow rates of STA and the bypass, average flow velocity in the proximal segment of transcranial bypass, transcranial pressure drop, and transcranial flow resistance were measured and compared with a postoperative increment of cerebral blood flow (CBF) in MCA territories derived from perfusion imaging. Per-branch pressure drop from model inlet to bypass branch outlet was calculated. RESULTS: The volumetric flow rates of STA and the bypass were 80.84 ± 14.54 mL/min and 46.03 ± 4.21 mL/min. Average flow velocity in proximal bypass, transcranial pressure drop, and transcranial flow resistance were 0.19 ± 0.07 m/s, 3.72 ± 3.10 mmHg, and 6.54 ± 5.65 10-8 Pa s m-3. Postoperative mean increment of CBF in MCA territories was 16.03 ± 11.72 mL·100 g-1·min-1. Per-branch pressure drop was 10.96 ± 5.59 mmHg and 7.26 ± 4.25 mmHg in branches with and without stenosis. CONCLUSIONS: CFD simulation results are consistent with CBF observation in verifying the efficacy of STA-MCA bypass, where postoperative stenosis may influence the hemodynamics.

Jasmonate Signaling Pathway Modulates Plant Defense, Growth, and Their Trade-Offs.

Lipid-derived jasmonates (JAs) play a crucial role in a variety of plant development and defense mechanisms. In recent years, significant progress has been made toward understanding the JA signaling pathway. In this review, we discuss JA biosynthesis, as well as its core signaling pathway, termination mechanisms, and the evolutionary origin of JA signaling. JA regulates not only plant regeneration, reproductive growth, and vegetative growth but also the responses of plants to stresses, including pathogen as well as virus infection, herbivore attack, and abiotic stresses. We also focus on the JA signaling pathway, considering its crosstalk with the gibberellin (GA), auxin, and phytochrome signaling pathways for mediation of the trade-offs between growth and defense. In summary, JA signals regulate multiple outputs of plant defense and growth and act to balance growth and defense in order to adapt to complex environments.

Collaborative Low-Rank Matrix Approximation-Assisted Fast Hyperspectral Raman Imaging and Tip-Enhanced Raman Spectroscopic Imaging.

Fast acquisition of Raman images is essential for accurately characterizing the analytes' information. In this paper, we developed a collaborative low-rank matrix approximation method for fast hyperspectral Raman imaging as well as tip-enhanced Raman spectroscopy (TERS) imaging. This method combines high signal-to-noise ratio (SNR) data with the target data to perform collaborative singular value decomposition. The high-quality reference data can impose constraints on factorization, which will force its components to approximate the true signal or noise components. The simulation demonstrated that this method offers state-of-the-art signal extraction performance and, thus, can be used to accelerate data acquisition. Specifically, the results indicate that the CLRMA can largely decrease the root-mean-square error by 20.92-54.12% compared with the baseline method of our previous study. We then applied this method to the fast TERS imaging of a Au/Pd bimetallic surface and significantly decreased the integration time down to 0.1 s/pixel, which is about 10 times faster than that of conventional experiments. High-SNR TERS spectra and clear TERS images that are well consistent with scanning tunneling microscopy (STM) images can be obtained even under such a weak signal condition. We further applied this method to the fast Raman imaging of HeLa cells and obtained clear Raman images at a short integration time of 2 s/line, which is about 5 times faster than that of conventional experiments. This method offers a promising tool for TERS imaging as well as conventional Raman imaging where fast data acquisition is required.

Deep Learning for Biospectroscopy and Biospectral Imaging: State-of-the-Art and Perspectives.

With the advances in instrumentation and sampling techniques, there is an explosive growth of data from molecular and cellular samples. The call to extract more information from the large data sets has greatly challenged the conventional chemometrics method. Deep learning, which utilizes very large data sets for finding hidden features therein and for making accurate predictions for a wide range of applications, has been applied in an unbelievable pace in biospectroscopy and biospectral imaging in the recent 3 years. In this Feature, we first introduce the background and basic knowledge of deep learning. We then focus on the emerging applications of deep learning in the data preprocessing, feature detection, and modeling of the biological samples for spectral analysis and spectroscopic imaging. Finally, we highlight the challenges and limitations in deep learning and the outlook for future directions.

Interplay between Müller cells and microglia aggravates retinal inflammatory response in experimental glaucoma.

BACKGROUND: Glaucoma, the leading cause of irreversible blindness, is a retinal neurodegenerative disease, which results from progressive apoptotic death of retinal ganglion cells (RGCs). Although the mechanisms underlying RGC apoptosis in glaucoma are extremely complicated, an abnormal cross-talk between retinal glial cells and RGCs is generally thought to be involved. However, how interaction of Müller cells and microglia, two types of glial cells, contributes to RGC injury is largely unknown. METHODS: A mouse chronic ocular hypertension (COH) experimental glaucoma model was produced. Western blotting, immunofluorescence, quantitative real-time polymerase chain reaction (q-PCR), transwell co-culture of glial cells, flow cytometry assay, ELISA, Ca2+ image, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) techniques were employed to investigate the interaction of Müller cells and microglia, and its underlying mechanisms in COH retina. RESULTS: We first showed that Müller cell activation in mice with COH induced microglia activation through the ATP/P2X7 receptor pathway. The activation of microglia resulted in a significant increase in mRNA and protein levels of pro-inflammatory factors, such as tumor necrosis factor-α and interleukin-6. These inflammatory factors in turn caused the up-regulation of mRNA expression of pro-inflammatory factors in Müller cells through a positive feedback manner. CONCLUSIONS: These findings provide robust evidence, for the first time, that retinal inflammatory response may be aggravated by an interplay between activated two types of glial cells. These results also suggest that to reduce the interplay between Müller cells and microglia could be a potential effective strategy for preventing the loss of RGCs in glaucoma.

Tumor necrosis factor-alpha aggravates gliosis and inflammation of activated retinal Müller cells.

Tumor necrosis factor-alpha (TNF-α), a major inflammatory factor released from activated retinal glial cells, is implicated in the pathogenesis of glaucoma. In this study, we investigated whether and how TNF-α may affect functional conditions of activated retinal Müller cells. Our results showed that in the group I metabotropic glutamate receptor (mGluR I) agonist DHPG-activated cultured Müller cells, TNF-α treatment aggravated cell gliosis, as evidenced by significantly increased expression of glial fibrillary acidic protein (GFAP). TNF-α treatment of the DHPG-activated Müller cells decreased cell proliferation and induced cell apoptosis. In normal Müller cells, TNF-α treatment increased the mRNA levels of leukocyte inhibitory factor (LIF), intercellular cell adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), and chemokine C-C-motif ligand 2 (CCL2), which could be significantly attenuated when Müller cells were pre-activated. However, TNF-α-induced elevation in mRNA levels of inflammatory factors, such as TNF-α, inducible nitric oxide synthase (iNOS), and interleukin-6 (IL-6), in normal Müller cells still kept higher levels when Müller cells were pre-activated. Furthermore, the TNF-α-induced changes of cytokines were partially mediated by NF-κB signaling pathway. Our results suggest that TNF-α may promote gliosis and inflammatory response of activated Müller cells, thus aggravating RGC injury in glaucoma.

Surface-Enhanced Raman Spectroscopy for Bioanalysis: Reliability and Challenges.

Surface-enhanced Raman spectroscopy (SERS) inherits the rich chemical fingerprint information on Raman spectroscopy and gains sensitivity by plasmon-enhanced excitation and scattering. In particular, most Raman peaks have a narrow width suitable for multiplex analysis, and the measurements can be conveniently made under ambient and aqueous conditions. These merits make SERS a very promising technique for studying complex biological systems, and SERS has attracted increasing interest in biorelated analysis. However, there are still great challenges that need to be addressed until it can be widely accepted by the biorelated communities, answer interesting biological questions, and solve fatal clinical problems. SERS applications in bioanalysis involve the complex interactions of plasmonic nanomaterials with biological systems and their environments. The reliability becomes the key issue of bioanalytical SERS in order to extract meaningful information from SERS data. This review provides a comprehensive overview of bioanalytical SERS with the main focus on the reliability issue. We first introduce the mechanism of SERS to guide the design of reliable SERS experiments with high detection sensitivity. We then introduce the current understanding of the interaction of nanomaterials with biological systems, mainly living cells, to guide the design of functionalized SERS nanoparticles for target detection. We further introduce the current status of label-free (direct) and labeled (indirect) SERS detections, for systems from biomolecules, to pathogens, to living cells, and we discuss the potential interferences from experimental design, measurement conditions, and data analysis. In the end, we give an outlook of the key challenges in bioanalytical SERS, including reproducibility, sensitivity, and spatial and time resolution.

Development of Weak Signal Recognition and an Extraction Algorithm for Raman Imaging.

Improving time resolution of Raman imaging is essential for the observation of dynamic processes involved in interfacial catalysis and biological systems. The crucial step is how to recognize and extract weak Raman signals overwhelmed in the strong noise under the low signal-to-noise ratio (SNR) condition. Here, by exploring the relationship between the SNR of a single Raman spectrum and the structural similarity (SSIM; the key parameter evaluating the image quality) of the whole image, we determined a semiempirical threshold with SNR = 0 dB for clear imaging for the first time. Therefore, we proposed one signal processing algorithm for fast Raman imaging by reconstructing the Raman spectrum with the aid of weak signal processing: extracting the reliable Raman signal of the target under the low SNR and then determining the suitable scanning time to obtain the Raman image with a trustworthy image quality. In the first step, fast Fourier transform (FFT), least squares, and 2-D median filter are sequentially applied to improve the SNR of each raw Raman spectrum. In the second step, a local SNR evaluation strategy is developed to predict image quality as well as the determination of clear imaging. The proposed method was successfully applied to the fast imaging of the cell under the low SNR condition.

Speeding Up the Line-Scan Raman Imaging of Living Cells by Deep Convolutional Neural Network.

Raman imaging is a promising technique that allows the spatial distribution of different components in the sample to be obtained using the molecular fingerprint information on individual species. However, the imaging speed is the bottleneck for the current Raman imaging methods to monitor the dynamic process of living cells. In this paper, we developed an artificial intelligence assisted fast Raman imaging method over the already fast line scan Raman imaging method. The reduced imaging time is realized by widening the slit and laser beam, and scanning the sample with a large scan step. The imaging quality is improved by a data-driven approach to train a deep convolutional neural network, which statistically learns to transform low-resolution images acquired at a high speed into high-resolution ones that previously were only possible with a low imaging speed. Accompanied with the improvement of the image resolution, the deteriorated spectral resolution as a consequence of a wide slit is also restored, thereby the fidelity of the spectral information is retained. The imaging time can be reduced to within 1 min, which is about five times faster than the state-of-the-art line scan Raman imaging techniques without sacrificing spectral and spatial resolution. We then demonstrated the reliability of the current method using fixed cells. We finally used the method to monitor the dynamic evolution process of living cells. Such an imaging speed opens a door to the label-free observation of cellular events with conventional Raman microscopy.

In Situ Imaging of Live-Cell Extracellular pH during Cell Apoptosis with Surface-Enhanced Raman Spectroscopy.

Extracellular pH (pHe) is an important regulating factor that determines many cellular processes, including proliferation, differentiation, and apoptosis. In our previous work, we developed 4-MPy (4-mercaptopyridine) modified Au nanoparticles as intracellular pH sensors based on surface-enhanced Raman spectroscopy (SERS). We herein modified a Au-nanoparticle-assembled solid SERS substrate with 4-MPy molecules for in situ pHe sensing during apoptosis. We found a more acidic extracellular environment of cancer cells than that of normal cells from the pH imaging. We then in situ investigated the temporal and spatial evolution of pHe of cancer cells after addition of transforming growth factor-ß (TGF-ß). The pHe showed a fast decrease at the beginning, followed by a slow decrease until the complete loss of cellular functions, and the pH values in and out of the cells became similar. This work shows that our SERS substrate combined with an in situ cell culture system is well suitable for in situ pHe sensing during cell processes and will be a promising technique for understanding more pHe-related biological and pathological issues.

Identification of the constituents and metabolites in rats after oral administration of Zi Shen Formula by UPLC-Q-TOF/MS combined pattern recognition analysis.

An ultra-high-performance liquid chromatography mass spectrometry method was established to detect and identify the chemical constituents of Zi Shen Formula (ZSF) and its metabolites in serum, urine and feces, after oral administration to rats. A total of 68 compounds were characterized in ZSF extracts. In vivo, 38 prototype components and 32 metabolites of ZSF were tentatively identified in rat serum, urine and feces. Seven metabolic pathways including demethylation, hydroxylation, oxidation, sulfation, glucuronidation, methylation and de-caffeoyl were proposed to be involved in the generation of these metabolites. It was found that glucuronidation, methylation and demethylation were the major metabolic processes of alkaloids, while demethylation, methylation, sulfation and de-caffeoyl were the major metabolic pathways of phenylethanoid glycosides. The main metabolic pathways of steroidal saponins were oxidation and isotype reactions. These findings are significant for our understanding of the metabolism of ZSF. The proposed metabolic pathways of bioactive components might be crucial for further studies of the mechanisms of action and pharmacokinetic evaluations of ZSF.

[Effect of Qishen Yiqi droplet on adenylate contents in myocardium of cor pulmonale rats].

Cor pulmonale rat models were induced by a single intraperitoneal injection of monocrotaline(MCT), and the sham group received a single intraperitioneal injection of normal saline. After the model rats received intragastric administration of Qishen Yiqi droplet(QS) for 6 weeks, the contents of adenylate(ATP, ADP and AMP) in right myocardial tissues were measured by HPLC, and then the metabolism changes in myocardium of cor pulmonale rats with QS were investigated. The results showed that ATP, ADP, and AMP were well separated, with a good linearity within a certain range of concentration; and the recovery rates were within the range of 90%-108%. As compared with model group, the level of ATP was significantly elevated in high-dose treatment group; ADP contents showed an increasing trend and AMP contents showed a decreasing trend, indicating that QS could significantly improve energy metabolism system in myocardium. By using the HPLC, a qualitative and quantitative analysis method was given for the determination of ATP, ADP and AMP contents in myocardium, providing a method for energy metabolism measurement in biological samples.

Raman Imaging from Microscopy to Nanoscopy, and to Macroscopy.

Raman spectroscopy can not only provide intrinsic fingerprint information about a sample, but also utilize the merits of the narrow bandwidth and low background of Raman spectra, offering itself as a promising multiplex analytical technique. Raman microscopy has become particularly attractive recently because it has demonstrated itself as an important imaging technique for various samples, from biological samples and chemical systems to industrially important silicon-based wafers. In this Concept article, some of the most recent advances in Raman imaging techniques are critically reviewed, and the advantages and problems associated with the current techniques are discussed. Particular emphasis is placed on its future directions, from both the technical and application sides.

Sequential recovery of copper and nickel from wastewater without net energy input.

A novel bioelectrochemical system (BES) was designed to recover copper and nickel from wastewater sequentially. The BES has two chambers separated by a bipolar membrane and two cathodes. Firstly, the copper ions were reduced on a graphite cathode with electricity output, and then with an additional bias-potential applied, the nickel ions were recovered sequentially on a copper sheet with electricity input. In this design, nickel and copper can be recovered and separated sequentially on two cathodes. By adjusting the molar ratio of copper and nickel ions to 2.99:1 in wastewater, 1.40 mmol Cu²âº could be recovered with 143.78 J electricity outputs, while 50.68 J electricity was input for 0.32 mmol nickel reduction. The total energy output of copper recovery was far more than the electricity input of nickel reduction. The present technology provides a potential method for heavy metal ion separation and recovery.

Hemodynamic Effects of Tortuosity and Stenosis in Superficial Temporal Artery-Middle Cerebral Artery Bypass for Moyamoya Disease.

BACKGROUND: Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery has been widely adopted in treating moyamoya disease (MMD). Geometric variations including high tortuosity and stenosis exist in many cases, but the hemodynamic effects have not been comprehensively evaluated. We aim to evaluate the hemodynamic effects of bypass geometry variations based on patient-specific data. METHODS: In total, 17 patients with MMD who underwent STA-MCA bypass surgery with highly tortuous bypass geometry were included. For each patient, the original 3-dimensional structure of STA-MCA bypass was reconstructed from clinical imaging data. The bypass structure was virtually improved by removing the tortuosity and stenosis. Computational fluid dynamics simulation was performed on both bypass structures under identical patient-specific condition. The simulated hemodynamic parameters of the bypass and its distal branches were compared between the original and virtually improved bypass geometries in all cases using paired t-test or Wilcoxon signed-rank test. The changes of hemodynamic parameters were compared between the cases with and without mild-to-moderate stenosis (44.0-70.3% in diameter) in the bypass using t-test or Mann-Whitney U test. RESULTS: The virtual improvement of bypass geometry significantly increased the flow rate of the bypass and its distal branches (P < 0.05) and decreased the transcranial flow resistance (P < 0.05). The hemodynamic changes in cases with stenosis removal were significantly greater than those without stenosis (P < 0.05). CONCLUSIONS: High tortuosity and stenosis can significantly change the hemodynamics of STA-MCA bypass, and the optimization of bypass geometry deserves further consideration.

Diagnostic Performance of Angiography-Derived Quantitative Flow Ratio in Complex Coronary Lesions.

BACKGROUND: Quantitative flow ratio derived from computed tomography angiography (CT-QFR) and invasive coronary angiography (Murray law-based quantitative flow ratio [µQFR]) are novel approaches enabling rapid computation of fractional flow reserve without the use of pressure guidewires and vasodilators. However, the feasibility and diagnostic performance of both CT-QFR and µQFR in evaluating complex coronary lesions remain unclear. METHODS: Between September 2014 and September 2021, 240 patients with 30% to 90% coronary diameter stenosis who underwent both coronary computed tomography angiography and invasive coronary angiography with fractional flow reserve within 60 days were retrospectively enrolled. The diagnostic performance of CT-QFR and µQFR in detecting functional ischemia among all lesions, especially complex coronary lesions, was analyzed using fractional flow reserve as the reference standard. RESULTS: CT-QFR and µQFR analyses were performed on 309 and 289 vessels, respectively. The diagnostic sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for CT-QFR in all lesions at the per-vessel level were 91% (with a 95% CI of 84%-96%), 92% (95% CI, 88%-95%), 83% (95% CI, 75%-90%), 96% (95% CI, 93%-98%), and 92% (95% CI, 88%-95%), with values for µQFR of 90% (95% CI, 81%-95%), 97% (95% CI, 93%-99%), 92% (95% CI, 84%-97%), 96% (95% CI, 92%-98%), and 94% (95% CI, 91%-97%), respectively. Among bifurcation, tandem, and moderate-to-severe calcified lesions, the diagnostic values of CT-QFR and µQFR showed great correlation and agreement with those of invasive fractional flow reserve, achieving an area under the receiver operating characteristic curve exceeding 0.9 for each complex lesion at the vessel level. Furthermore, the accuracies of CT-QFR and µQFR in the gray zone were 85% and 84%, respectively. CONCLUSIONS: Angiography-derived quantitative flow ratio (CT-QFR and µQFR) demonstrated remarkable diagnostic performance in complex coronary lesions, indicating its pivotal role in the management of patients with coronary artery disease.

Compare image quality of T2-weighted imaging with different phase acceleration factors.

Previous studies demonstrated that adjusting the phase acceleration (PA) factors could influence image quality. To improve image quality and decrease respiratory artifacts of lesions in the liver on T2-weighted image by adjusting PA factor and number of excitation (NEX). Sixty consecutive patients with hepatic lesions were enrolled in this prospective research between May 2020 and June 2020. All patients had 3.0T magnetic resonance imaging with 4 sequences (combining PA factors and NEXs, the former was 2 and 3, the latter were 1.5 and 2, respectively, with the same other scanning parameters). Two readers used 5-point quality scales to assess image quality. The signal intensity was measured by drawing regions of interest in the liver, spleen, and background on the T2-weighted imaging. Artifacts, overall image impression, and vascular conspicuity were better when the PA factor was 3 than 2. Artifacts and vascular conspicuity were better when NEX was 2 than 1.5. PA factor 3 and NEX 2 got a higher score in 5-point quality scales and less scan time than the other 3 sequences. Meanwhile, the signal-to-noise ratio of PA factor 3 and NEX 2 was best among these 4 sequences. PA factor and NEX could influence the imaging quality and lesion-to-hepatic contrast in detecting hepatic lesions on T2-weighted images. PA factor 3 and NEX 2 may have a positive effect in the clinic, especially for those with irregular respiration, as it decreased artifacts and reduced scan time.

P2X7/P2X4 Receptors Mediate Proliferation and Migration of Retinal Microglia in Experimental Glaucoma in Mice.

Microglia are involved in the inflammatory response and retinal ganglion cell damage in glaucoma. Here, we investigated how microglia proliferate and migrate in a mouse model of chronic ocular hypertension (COH). In COH retinas, the microglial proliferation that occurred was inhibited by the P2X7 receptor (P2X7R) blocker BBG or P2X7R knockout, but not by the P2X4R blocker 5-BDBD. Treatment of primary cultured microglia with BzATP, a P2X7R agonist, mimicked the effects of cell proliferation and migration in COH retinas through the intracellular MEK/ERK signaling pathway. Transwell migration assays showed that the P2X4R agonist CTP induced microglial migration, which was completely blocked by 5-BDBD. In vivo and in vitro experiments demonstrated that ATP, released from activated Müller cells through connexin43 hemichannels, acted on P2X7R to induce microglial proliferation, and acted on P2X4R/P2X7R (mainly P2X4R) to induce microglial migration. Our results suggest that inhibiting the interaction of Müller cells and microglia may attenuate microglial proliferation and migration in glaucoma.