TRLS: A Time Series Representation Learning Framework via Spectrogram for Medical Signal Processing

Representation learning frameworks in unlabeled time series have been proposed for medical signal processing. Despite the numerous excellent progresses have been made in previous works, we observe the representation extracted for the time series still does not generalize well. In this paper, we present a Time series (medical signal) Representation Learning framework via Spectrogram (TRLS) to get more informative representations. We transform the input time-domain medical signals into spectrograms and design a time-frequency encoder named Time Frequency RNN (TFRNN) to capture more robust multi-scale representations from the augmented spectrograms. Our TRLS takes spectrogram as input with two types of different data augmentations and maximizes the similarity between positive ones, which effectively circumvents the problem of designing negative samples. Our evaluation of four real-world medical signal datasets focusing on medical signal classification shows that TRLS is superior to the existing frameworks.Comment: This paper is accept by ICASSP 2024. This is a more detailed versio

Key defatting tissue pretreatment protocol for enhanced MALDI MS Imaging of peptide biomarkers visualization in the castor beans and their attribution applications

IntroductionCastor bean or ricin-induced intoxication or terror events have threatened public security and social safety. Potential resources or materials include beans, raw extraction products, crude toxins, and purified ricin. The traceability of the origins of castor beans is thus essential for forensic and anti-terror investigations. As a new imaging technique with label-free, rapid, and high throughput features, matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) has been gradually stressed in plant research. However, sample preparation approaches for plant tissues still face severe challenges, especially for some lipid-rich, water-rich, or fragile tissues. Proper tissue washing procedures would be pivotal, but little information is known until now.MethodsFor castor beans containing plenty of lipids that were fragile when handled, we developed a comprehensive tissue pretreatment protocol. Eight washing procedures aimed at removing lipids were discussed in detail. We then constructed a robust MALDI-MSI method to enhance the detection sensitivity of RCBs in castor beans.Results and DiscussionA modified six-step washing procedure was chosen as the most critical parameter regarding the MSI visualization of peptides. The method was further applied to visualize and quantify the defense peptides, Ricinus communis biomarkers (RCBs) in castor bean tissue sections from nine different geographic sources from China, Pakistan, and Ethiopia. Multivariate statistical models, including deep learning network, revealed a valuable classification clue concerning nationality and altitude

Incorporating MicroRNA into molecular phenotypes of circulating tumor cells enhances the prognostic accuracy for patients with metastatic breast cancer

Background. The molecular phenotype of circulating tumor cells (CTCs) was associated with clinical outcome of patients with breast cancer. CTCs isolated from patients with metastatic breast cancer (MBC) display a unique microRNA (miRNA) expression profile. The aim of this study was to enhance the prognostic accuracy of the CTC phenotype in patients with MBC, by incorporating miRNA into a combined prediction model. Subjects, Materials, and Methods. CTCs were detected by CellSearch and enriched by magnetic cell sorting. miRNA deep sequencing and quantitative polymerase chain reaction were used to screen and verify potentially CTC‐specific miRNA candidates. Patients with MBC were enrolled from two independent cohorts, and overall survival (OS) and chemotherapy response were analyzed. Results. We screened and identified that miR‐106b was an upregulated molecule in patients with MBC with CTC ≥5/7.5 mL (n = 16) compared with patients with CTC = 0/7.5 mL (n = 16) and healthy donors (n = 8). The expression of CTC‐specific miR‐106b correlated with vimentin and E‐cadherin in CTC and acted as an independent factor for predicting OS (hazard ratio 2.157, 95% confidence interval [CI] 1.098–4.239, p = .026). Although CTC‐specific miR‐106b, E‐cadherin, and vimentin showed a prognostic potential independently, the prognostic performance for OS based on the combination of three markers was significantly enhanced in Cohort 1 (area under the curve [AUC] 0.752, 95% CI 0.658–0.847, n = 128) and further validated in Cohort 2 (AUC 0.726, 95% CI 0.595–0.856, n = 91). Besides, a combined model incorporating miR‐106b was associated with therapy response. Conclusion. The phenotypic assemblies of CTC incorporating miR‐106b show enhanced prognostic accuracy of overall survival in patients with MBC

Assessment of health risks posed by toxicological elements of the food chain in a typical high geologic background

Enrichment of toxicological elements in soils of high geologic background has a significant effect on toxicity. The aim of this study was to assess the health risks associated with the transfer of toxicological elements in the food chain in a typical high geologic background. We systematically collected data on rocks, soils and food crops belonging to a typical black rock system geological body and at the same time belonging to the main grain-producing areas in Hunan Province, and analyzed the exposure and health threat of toxicological elements Cr, Cd, Pb, Hg, As and Se in cucumber, rape, soybean, peanut and ginger. Based on the JISEVM method to establish the spatial contamination constitutive relationship between rock-soil-food, we deduced the conclusions from the bioconcentration factor (BCF), integrated crop contamination index (P) and hazard index (HI). Our results showed that Cr, Cd, Pb, Hg, and Se were exceeded in agricultural soils, with Hg and Se levels severely exceeding the standard Se was most bioconcentrated in soybean (BCF = 0.5855), followed by Cd (BCF = 0.5603) and Se (BCF = 0.3800) in peanut and Se (BCF = 0.4255) in rape, and the BCFs of all the BCF of crops were less than 1, and the enrichment of these six elements in the food chain did not reach a dangerous level; the overall spatial distribution of radioactive contamination was centered on the black rocky geologic body; and the contamination and absorption levels of foods in the study area were: leafy vegetables (oilseed rape) > legumes (soybeans and peanuts) > stem vegetables (ginger) > fruit vegetables (cucumber). The intake of Cd and Se through consumption of oilseed rape was the most important source of health risk among foods in the study area. This study, since it can fill the gap in risk assessment due to endogenous factors in a high geologic background, can also guide studies in other specialized contexts or in a multi-media background

Potential toxic elements (PTEs) in rhizosphere soils and crops under a black shale high geological background: Pollution characteristics, distribution and risk assessment

The LouShao Basin in Hunan Province is covered with two sets of black rock series containing various potential toxic heavy metal elements. The rock series are rich in various potential toxic heavy metal elements, and the weathered black shale is the main formation of local farmland soil, making it a typical area with high geological background in China. The purpose of this study is to assess the regional ecological and health risks by studying the correlation between the content of heavy metal elements enriched in rhizosphere soil, non-rhizosphere soil, and crops, and the concentration of heavy metal elements in the main source, black shale rocks. The results show that the elements in the black shale far exceed the world average of rock, severely affecting soil element concentrations. Se element is the most severely polluted in rhizosphere soil, exceeding the background value by 7 times. The concentration of heavy metals between rock-non-rhizosphere soil-rhizosphere soil-crops decreases linearly. The distribution of pollution has strong spatial autocorrelation, and the high geological background is the main reason. Pollution index results show significant pollution of Se, Cr, Hg, and Cd in crops, with the pollution of heavy metal element Cr in corn being extremely serious with Igeo = 6.71. The ecological risk order is Se > Cd > Cr > As > Pb > Hg. Humans mainly contact elements through skin contact and food chain intake. The HI value of heavy metal element Cd is greater than 1, indicating a high carcinogenic risk. Human exposure to Cd through skin contact and food chain intake may lead to related diseases such as kidney stones, and pose greater harm to children

Resveratrol Preincubation Enhances the Therapeutic Efficacy of hUC-MSCs by Improving Cell Migration and Modulating Neuroinflammation Mediated by MAPK Signaling in a Mouse Model of Alzheimer’s Disease

<jats:p>Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) are promising for the treatment of Alzheimer’s disease (AD). However, their low rate of migration and survival in the brain limit their clinical applicability. This study is designed to improve the therapeutic potential of hUC-MSCs by preincubating them with resveratrol, a natural polyphenol capable of regulating cell destiny. Herein, we demonstrate that resveratrol preincubation enhances the migration of hUC-MSCs <jats:italic>in vitro</jats:italic>, as well as their survival and homing into the hippocampus of AD mice <jats:italic>in vivo</jats:italic>. Moreover, resveratrol-primed MSCs were better able to inhibit amyloid-β peptide (Aβ) deposition, Tau hyperphosphorylation, and oxidative stress, all while improving learning and memory. Notably, we found that hUC-MSCs inhibited neuroinflammation by reacting with astrocytes and microglial cells and suppressing mitogen-activated protein kinases (MAPKs), extracellular signal kinases (ERK), p38 kinases (p38), and c-Jun N-terminal kinases (JNK) signaling pathways in the hippocampus of AD mice. Furthermore, resveratrol pretreatment enhanced these effects. Conclusively, the current study revealed that resveratrol preconditioning protected hUC-MSCs against the hostile microenvironment characteristic of AD and enhanced their viability and homing into the brain of AD mice. The use of resveratrol-pretreated hUC-MSCs is thereby proposed to be a promising therapy for AD.</jats:p&gt

Cu₂ZnSnS₄ Nanoparticle Sensitized Metal–Organic Framework Derived Mesoporous TiO₂ as Photoanodes for High-Performance Dye-Sensitized Solar Cells

We present a facile hot injection and hydrothermal method to synthesize Cu₂ZnSnS₄ (CZTS) nanoparticles sensitized metal–organic frameworks (MOFs)-derived mesoporous TiO₂. The MOFs-derived TiO₂ inherits the large specific surface area and abundantly porous structures of the MOFs structure, which is of great benefit to effectively enhance the dye loading capacity, prolong the incident light traveling length by enhancing the multiple interparticle light-scattering process, and therefore improve the light absorption capacity. The sensitization of CZTS nanoparticles effectively enlarges the photoresponse range of TiO₂ to the visible light region and facilitates photoinduced carrier transport. The formed heterostructure between CZTS nanoparticles and MOFs-derived TiO₂ with matched band gap structure effectively suppresses the recombination rates of photogenerated electron/hole pairs and prolongs the lifespan of the carriers. Photoanodes based upon CZTS/MOFs-derived TiO₂ photoanodes can achieve the maximal photocurrent of 17.27 mA cm^–2 and photoelectric conversion performance of 8.10%, nearly 1.93 and 2.21 times higher than those of TiO₂-based photoanode. The related mechanism and model are investigated. The strikingly improved photoelectric properties are ascribed to a synergistic action between the MOFs-derived TiO₂ and the sensitization of CZTS nanoparticles

Rapid Separation of Enantiomeric Impurities in Chiral Molecules by a Self-Referential Weak Measurement System

We propose a self-referential fast detection scheme for a frequency domain weak measurement system for the detection of enantiomeric impurities in chiral molecules. In a transmissive weak measurement system, the optical rotation (OR) is used to modify the pre-selected polarization state and the post-selection polarization state. We obtained the sum and difference of the optical rotations produced by the sample and the standard by rotating the quarter wave plate in the system. Then, we estimate the ratio of chiral molecules to enantiomeric impurities using the ratio of the central wavelength shifts caused by the addition and subtraction states described above. In this paper, our system has an optical resolution of 1.88 × 10−5°. At the same time, we completed the detection of the ratio of the two substances in the mixture of L-proline and D-proline in different proportions, which proved that our system can quickly detect the content of enantiomeric impurities in chiral molecules