18F-FDG PET/CT Radiomics-Based Multimodality Fusion Model for Preoperative Individualized Noninvasive Prediction of Peritoneal Metastasis in Advanced Gastric Cancer.

PURPOSE: This study was designed to develop and validate a machine learning-based, multimodality fusion (MMF) model using 18F-fluorodeoxyglucose (FDG) PET/CT radiomics and kernelled support tensor machine (KSTM), integrated with clinical factors and nuclear medicine experts' diagnoses to individually predict peritoneal metastasis (PM) in advanced gastric cancer (AGC). METHODS: A total of 167 patients receiving preoperative PET/CT and subsequent surgery were included between November 2006 and September 2020 and were divided into a training and testing cohort. The PM status was confirmed via laparoscopic exploration and postoperative pathology. The PET/CT signatures were constructed by classic radiomic, handcrafted-feature-based model and KSTM self-learning-based model. The clinical nomogram was constructed by independent risk factors for PM. Lastly, the PET/CT signatures, clinical nomogram, and experts' diagnoses were fused using evidential reasoning to establish the MMF model. RESULTS: The MMF model showed excellent performance in both cohorts (area under the curve [AUC] 94.16% and 90.84% in training and testing), and demonstrated better prediction accuracy than clinical nomogram or experts' diagnoses (net reclassification improvement p < 0.05). The MMF model also had satisfactory generalization ability, even in mucinous adenocarcinoma and signet ring cell carcinoma which have poor uptake of 18F-FDG (AUC 97.98% and 89.71% in training and testing). CONCLUSIONS: The 18F-FDG PET/CT radiomics-based MMF model may have significant clinical implications in predicting PM in AGC, revealing that it is necessary to combine the information from different modalities for comprehensive prediction of PM.

[Mechanism Research of lncRNA miR143HG on Regulating the Biological Behavior 
of Lung Squamous Cell Carcinoma H520 Cells].

BACKGROUND: There is a high morbidity, mortality, and poor clinical prognosis of lung squamous cell carcinoma (LUSC). However, there is currently no effective targeted treatment plan for LUSC. As a long non-coding RNA (lncRNA), lncRNA miR143HG has been proven to play an important role in the occurrence and development of various tumors. However, the biological role played by lncRNA miR143HG in LUSC cells is still unclear. Therefore, this study aimed to investigate the mechanism of lncRNA miR143HG on regulating the biological behavior of LUSC H520 cells. METHODS: Pan-cancer analysis and differential expression analysis of lncRNA miR143HG were performed based on The Cancer Genome Atlas (TCGA) database. The predictive effect of lncRNA miR143HG on the diagnosis and prognosis of LUSC was evaluated by adopting the receiver operating characteristic (ROC) curve and timeROC curve. The enrichment degree of each pathway to lncRNA miR143HG was determined. The expression of lncRNA miR143HG and miR-155 in BEAS-2B cells and H520 cells was detected using quantitative real-time polymerase chain reaction (qRT-PCR). H520 cells were randomly divided into blank control group (without any treatment), negative control group (transfected with lncRNA-NC), lncRNA miR143HG group (transfected with lncRNA miR143HG), and lncRNA miR143HG+miR-155 group (co-transfected with lncRNA miR143HG and miR-155). The approaches of CCK-8, wound healing test, Transwell assay, flow cytometry, qRT-PCR, and Western blot were respectively employed to detect the cell proliferation ability, cell migration ability, cell invasion ability, cell apoptosis rate, and expression level of related genes and proteins of the Wnt/ß-Catenin pathway. RESULTS: The results of pan-cancer analysis and differential analysis collectively showed that except for renal clear cell carcinoma, the expression of lncRNA miR143HG in other cancer tissues was higher than that in healthy tissues, and the differences were significant in LUSC. The evaluation results of the ROC curve and timeROC curve suggested that lncRNA miR143HG was of great significance in the prediction of diagnosis and prognosis of LUSC. The pathways enriched in high expression of lncRNA miR143HG mainly included focal adhesion, vascular smooth muscle contraction, calcium signaling pathways, and so on; the pathways enriched in the low expression of lncRNA miR143HG embraced oxidative phosphorylation, cell cycle, basic transcription factors, etc. The qRT-PCR results showed that lncRNA miR143HG was low expressed but miR-155 was highly expressed in H520 cells when compared to BEAS-2B cells (P<0.05). Compared with the negative control group, the expression levels of the gene of lncRNA miR143HG, the gene and protein of Wnt, as well as the gene and protein of ß-Catenin were significantly increased, while the gene expression of miR-155, the ability of cell proliferation, cell migration, and cell invasion were significantly reduced, but the cell apoptosis rate was dominantly elevated in cells of lncRNA miR143HG group (P<0.05). In addition, compared with the lncRNA miR143HG group, overexpression of miR-155 could reverse the biological behavior mediated by lncRNA miR143HG, and the difference was statistically significant (P<0.05). CONCLUSIONS: LncRNA miR143HG was of great significance for the biological behavior of H520 cells. LncRNA miR143HG inhibited the ability of proliferation, migration, and invasion, as well as enhanced the apoptosis of H520 cells by downregulating miR-155 expression, which may be related to the Wnt/ß-Catenin pathway.
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Li isotopic seasonality in a small catchment at the northeastern Tibetan Plateau: Roles of hydrology and temperature dependency.

Silicate weathering is critical to sustain our habitable planet. Lithium (Li) isotopes enable us to investigate the nature of silicate weathering. A number of riverine Li isotope (δ7Lirw) investigations have been made from polar to equatorial terrains, but there remains no consensus about the controlling mechanisms of both weathering and δ7Lirw. Here we investigated δ7Lirw response to climate by collecting weekly river water samples in a small catchment (the Buha River within the Lake Qinghai basin) on the northeastern Tibetan Plateau, with stable tectonic, lithology, and topography. In the hydrology year of 2007 of the Buha River, we find that during the dry seasons, δ7Lirw ratios show temperature dependency typically, when the groundwater fed the river. During the monsoon seasons, δ7Lirw were obviously lower than the temperature dependency predicted values, when abundant rock dissolved and thereby fresh Li release into rivers. We propose that the hydrology and temperature dependency together play important roles in regulating δ7Lirw ratios in such an alpine small catchment. The mechanism is that long residence time facilitates the equilibrium chemical and Li isotopic fractionation during the dry seasons, so a temperature dependency of δ7Lirw is achieved. In contrast, rapid erosion and weathering contribution of fresh rock-like δ7Li to river water would significantly decrease δ7Lirw ratios during the monsoon seasons. This hypothesis can better interpret previously reported data of seasonal δ7Lirw variation, as a superposition between temperature dependency and hydrology regulation on silicates weathering in the small catchments besides tectonics.

Quantifying the impact of recovery during chromatographic purification on the accuracy of lithium isotopic determination by multi-collector inductively coupled plasma mass spectrometry.

RATIONALE: Lithium (Li) isotopes have increasingly been applied as tracers in Earth and planetary sciences and their effectiveness relies upon accurate and precise Li isotopic data. Nowadays, multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) combined with chromatographic purification is the most common strategy for obtaining Li isotopic ratios in natural samples, with a long-term internal precision better than 0.3‰ in most laboratories. However, there is a large discrepancy in the Li isotopic compositions of the same reference materials determined by MC-ICP-MS among international laboratories (e.g. ca 3.5‰ difference for measurements of homogeneous seawater), which has been attributed to insufficient recovery of Li during chromatographic purification. Despite this recognition, the exact impact of Li recovery during purification on Li isotopic determinations by MC-ICP-MS has never been quantified. METHODS: We employed a normal distribution function to model Li elution curves and quantified the Li isotopic fractionation resulting from Li recovery during chromatographic purification. Furthermore, we compared the calculated and measured relative recovery (R) with the Li isotopic ratios determined by ICP-MS to validate our theoretical calculation. RESULTS: The theoretical calculations showed that R should be higher than 99.8% in order to avoid observable Li isotopic fractionation during chromatographic purification at IEECAS. This idea is further supported by the better long-term external precisions for data with R ≥ 99.8% compared with previous values of 99.5% ≤ R < 99.8%. Our results indicated that the large differences in the reported Li isotopic ratios for homogeneous seawater among international laboratories are probably attributable to Li isotopic fractionation occurring during ion exchange chromatography. CONCLUSIONS: Our theoretical calculation via R is the first quantitative and convenient approach for monitoring Li isotopic fractionation during sample purification, ensuring that R ≥ 99.8% can avoid observable Li isotopic fractionation during purification, which will improve the accuracy of Li isotopic measurements by MC-ICP-MS and the comparability among laboratories.

Monsoonal control on a delayed response of sedimentation to the 2008 Wenchuan earthquake.

Infrequent extreme events such as large earthquakes pose hazards and have lasting impacts on landscapes and biogeochemical cycles. Sediments provide valuable records of past events, but unambiguously identifying event deposits is challenging because of nonlinear sediment transport processes and poor age control. Here, we have been able to directly track the propagation of a tectonic signal into stratigraphy using reservoir sediments from before and after the 2008 Wenchuan earthquake. Cycles in magnetic susceptibility allow us to define a precise annual chronology and identify the timing and nature of the earthquake's sedimentary record. The grain size and Rb/Sr ratio of the sediments responded immediately to the earthquake. However, the changes were muted until 2 years after the event, when intense monsoonal runoff drove accumulation of coarser grains and lower Rb/Sr sediments. The delayed response provides insight into how climatic and tectonic agents interact to control sediment transfer and depositional processes.

Determination of Barium Isotopic Ratios in River Water on the Multiple Collector Inductively Coupled Plasma Mass Spectrometer.

Barium (Ba) isotopes have been booming while providing ubiquitous traceability to various geochemical/oceanographical processes in recent years. Accurate and precise determinations of Ba isotopes is the main precondition to apply them to tracing various processes. However, a particular determination method is lacking for Ba isotopic ratios in river water. Compared to the double-spike method which needs expensive spikes, intensive laboratory operation, and complex calibration, sample-standard bracketing (SSB) is an easier and more convenient method to obtain isotopic data on the multiple collector inductively coupled plasma mass spectrometer. In this study, to obtain the Ba isotopic ratio of river-water samples with a rather lower Ba concentration than igneous rock, we experimented with K, Ca, Na, Mg, and Ce doping tests. The acidity and concentration matches to explore suitable SSB method conditions for river water Ba isotopic determinations on an MC-ICP-MS. The results showed no obvious matrix effects to Ba isotopes when K/Ba, Ca/Ba, Na/Ba, and Mg/Ba <5, and Ce/Ba <0.2, indicating that the matrix effects are negligible after column purification of Ba. HNO3 concentration match tests showed that within a 25% acidity difference, there would be also no systematic effects to a Ba isotopic determination. However, Ba isotopic determinations are highly sensitive to the Ba concentration difference between the standard and the sample. We observed a mismatch between the Ba concentration and its isotopic ratios, even when the concentration was strictly within a 5% difference. Nevertheless, the on-peak zero strategy (i.e. subtraction of HNO3, gas, and instrumental blanks) worked well to solve the mismatch situation. With this easy strategy, the Ba isotopic ratios of batch natural rive-water samples with various Ba concentrations will become easily accessible.

Effects of cone combinations on accurate and precise Mg-isotopic determination using multi-collector inductively coupled plasma mass spectrometry.

RATIONALE: High-precision determination of magnesium (Mg) isotopes can now be routinely achieved by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The analytical sensitivity and instrumental mass discrimination behavior of this method are, however, sensitive to the types of sample and skimmer cones used in these measurements, so it is important that these parameters should be investigated. METHODS: Using the sample-standard-bracketing method in the wet-plasma mode, four available combinations of sample and skimmer cones [Jet sample cone + H skimmer cone (Jet + H), standard sample cone + H skimmer cone (Standard + H), standard sample cone + X skimmer cone (Standard + X), and Jet sample cone + X skimmer cone (Jet + X)] were systematically investigated for peak shape, sensitivity, mass discrimination, accuracy, and precision in Mg-isotopic ratio determination using a Neptune plus MC-ICP mass spectrometer. RESULTS: The results showed that different cone combinations do not affect peak shapes but would significantly change the sensitivities for Mg-isotopic determinations. Compared with using the Standard + H, the sensitivities of Mg-isotopic determinations were enhanced by approximately a factor of 1.3, 1.4, and 1.9 by using the Standard + X, the Jet + H, and the Jet + X combinations, with the most stable mass discrimination behaviors obtained by the Jet + H. The instrumental mass fractionation slope for any combination of a modified cone geometry (i.e. Standard + X, Jet + X, and Jet + H) is 0.500, while it is 0.510 for the Standard + H. In addition, the mass discrimination behavior is related to Mg concentrations once the combination is set, indicating the necessity of concentration match during Mg-isotopic determination. CONCLUSIONS: The precision and accuracy of the Jet + H combination are better than those of the other combinations, and this is further supported by the validation of the Mg-isotope data for four international reference materials: Cambridge-1, NASS-6, AGV-2, and BHVO-2. As the Jet + H combination also provides a high signal, this combination gives the most robust strategy for the highly precise and accurate determination of Mg isotopes.