Monitoring Enzymatic Reaction Kinetics and Activity Assays in Confined Nanospace.

Enzyme-mediating biotransformations commonly occur in micro- and nanospace, which is crucial to maintain the essential biochemical processes and physiological functions in living systems. Probing enzyme-catalytic reactions in a biomimetic fashion remains challenging due to the lack of competent tools and methodology. Here, we show that studying enzymatic reaction kinetics can be readily achieved by a well-designed solid-state nanopore. Using tyrosine as a classical substrate, we quantitatively characterize the catalytic activity of tyrosinase (TYR) and tyrosine decarboxylase (TDC) in a nanoconfined space. Tyrosine was first immobilized in the nanopipette, wherein the active sites of tyrosine were left unoccupied. When successively exposed to TYR and TDC, a two-step cascade reaction can spontaneously take place. In this process, the surface wettability and charge of the nanopipette stemming from the catalytic products can sensitively regulate ion transport and ionic current rectification behavior, which were monitored by ionic current signal. In this biomimetic scenario, we obtained the enzymatic reaction kinetics of monophenyl oxidase that were not previously actualized in the conventional macroenvironment. Significantly, TYR showed higher enzyme activity, with a Km value of 1.59 mM, which was lower than that measured in a free and open space (with a Km of 3.01 mM). This suggests that tyrosine should be the most appropriate substrate of TYR, thus improving our understanding of tyrosine-associated biochemical reactions. This work offers an applicable technical platform to mimic enzyme-mediated biotransformations and biometabolisms.

Adsorption of LIBs Thermal Runaway Gases on TM-Decorated HfS2 Surface: A DFT Study.

With the wide application of lithium-ion batteries (LIBs) in different fields, safety accidents occur frequently. Therefore, it is necessary to monitor the thermal runaway gas for an early warning. In this article, the adsorption properties of the characteristic gases of LIBs thermal runaway gases are studied by density functional theory (DFT). The adsorption structure of TM (Co/Rh/Ir)-decorated HfS2 (TM@HfS2) is established, and its adsorption properties for C2H4, CH4, and CO are studied. The adsorption energy, charge transfer, band, DOS, charge difference density, work function, and recovery time are discussed in detail. The results show that Ir@HfS2 has the strongest adsorption performance for C2H4 and CO, so C2H4 and CO can be stably adsorbed on the surface of the Ir@HfS2 monolayer. The adsorption energy of CH4 on Co@HfS2 is stronger than those of Rh@HfS2 and Ir@HfS2, but the adsorption energy is still very small. By applying biaxial strain to Co@HfS2, we found that the adsorption energy increases with the increase in negative strain. This study provides a theoretical basis for the regulation of the adsorption properties of HfS2 by different transition metals.

Identification of host gene regulation and resistance pathway dynamics at diverse infection stages of Rhizoctonia solani AG3-TB.

Rhizoctonia solani is a fungal pathogen that causes significant losses in agricultural production. Because of its rapid transmission and broad host range, the exploration of genes involved in defense responses to the infection of R. solani has become an important task. Here, we performed a time-course RNA-Seq experiment to explore crucial genes or pathways involved in host responses to R. solani AG3-TB infection at 6, 12, 24, 36, 48, and 72 hours post inoculation (hpi). GO and KEGG enrichment analysis revealed that most DEGs were enriched in the basal metabolism pathways, including carbohydrate metabolic processes and the biosynthesis of amino acids. Moreover, catalase (CAT) and superoxide dismutase (SOD) were up-regulated, and transcription factors (TFs) such as WRKY, AP2, and MYB were increased significantly compared to the control (0 hpi). Silencing of WRKY70 and catalase-3 exhibited elevated susceptibility to the fungal infection. To summarize, the TFs WRKY70 and WRKY75, genes involved in jasmonic acid (JA), salicylic acid (SA), and brassinosteroids (BR) signaling pathways, and defense-related enzymes may play crucial roles in the host responses to R. solani AG3-TB infection.

A data-driven combined prediction method for the demand for intensive care unit healthcare resources in public health emergencies.

BACKGROUND: Public health emergencies are characterized by uncertainty, rapid transmission, a large number of cases, a high rate of critical illness, and a high case fatality rate. The intensive care unit (ICU) is the "last line of defense" for saving lives. And ICU resources play a critical role in the treatment of critical illness and combating public health emergencies. OBJECTIVE: This study estimates the demand for ICU healthcare resources based on an accurate prediction of the surge in the number of critically ill patients in the short term. The aim is to provide hospitals with a basis for scientific decision-making, to improve rescue efficiency, and to avoid excessive costs due to overly large resource reserves. METHODS: A demand forecasting method for ICU healthcare resources is proposed based on the number of current confirmed cases. The number of current confirmed cases is estimated using a bilateral long-short-term memory and genetic algorithm support vector regression (BILSTM-GASVR) combined prediction model. Based on this, this paper constructs demand forecasting models for ICU healthcare workers and healthcare material resources to more accurately understand the patterns of changes in the demand for ICU healthcare resources and more precisely meet the treatment needs of critically ill patients. RESULTS: Data on the number of COVID-19-infected cases in Shanghai between January 20, 2020, and September 24, 2022, is used to perform a numerical example analysis. Compared to individual prediction models (GASVR, LSTM, BILSTM and Informer), the combined prediction model BILSTM-GASVR produced results that are closer to the real values. The demand forecasting results for ICU healthcare resources showed that the first (ICU human resources) and third (medical equipment resources) categories did not require replenishment during the early stages but experienced a lag in replenishment when shortages occurred during the peak period. The second category (drug resources) is consumed rapidly in the early stages and required earlier replenishment, but replenishment is timelier compared to the first and third categories. However, replenishment is needed throughout the course of the epidemic. CONCLUSION: The first category of resources (human resources) requires long-term planning and the deployment of emergency expansion measures. The second category of resources (drugs) is suitable for the combination of dynamic physical reserves in healthcare institutions with the production capacity reserves of corporations. The third category of resources (medical equipment) is more dependent on the physical reserves in healthcare institutions, but care must be taken to strike a balance between normalcy and emergencies.

First Report of Rhizoctonia solani AG1-IB Causing Tobacco Target Spot in China.

Tobacco target spot, caused by Rhizoctonia solani Kühn, induces shot-hole lesions on leaves that that significantly reduce yield and quality of tobacco. In July 2022, samples (n=5) with target spot were collected from three tobacco fields, one each in Puer (22.63°N, 100.72°E, cv. Yunyan87) and Mengzi (23.26°N, 103.36°E, cv. Yunyan87) of Yunnan province and one in Dandong (40.63°N, 124.18°E, cv. Liaoyan17) of Liaoning province, China; disease incidence in these fields was approximately 30%~40%. Initial symptoms (2- to 3-mm-diameter lesions) appeared on the middle to lower leaves, then expanded to 2 to 3 cm in diameter and developed the shot-hole appearance. Pieces of tissue (5×5 mm) were cut from the edge of lesions, surface sterilized, rinsed in sterile water, then placed on the surface of water agar (WA) and incubated at 25℃ for 2 days in the dark. Single hyphal tips were taken from fungal isolates identified as R. solani based on the morphological traits (Tsror 2010), then transferred onto potato dextrose agar (PDA) and cultured for 3 d as described above. A total of 15 pure cultures were obtained. With the exception of YN-3 (isolated from Puer), YN-62 (isolated from Mengzi) and LN-95(isolated from Dandong) strains, which exhibited hyphal fusion reaction with AG1-IB standard strain, all the other strains demonstrated hyphal fusion with AG-3 standard strain (Ogoshi 1987). Genomic DNA of these three strains were extracted by the CTAB method and ITS regions of rDNA were sequenced (White et al. 1990). The sequences were deposited in GenBank with accession No. OR770079, OR770080 and OR770082. All the three rDNA-ITS sequences exhibited 99.85% similar to AG1-IB found in GenBank, and a phylogenetic tree using a neighbor-joining method grouped the three strains within the R. solani AG-1 IB clade. Therefore, based on the hyphal fusion reaction and molecular methods, these isolates were identified as R. solani AG1-IB. To determine pathogenicity of the isolates, the healthy leaves of tobacco plants (cv. Yunyan 87) were used. Five-mm-diameter mycelial plugs of the strain on PDA were inoculated on leaves that had been previously wounded with a sterile needle, and cotton balls moistened with sterile water were used for moisturizing the inoculation sites. Ten leaves were inoculated for each strain and leaves inoculated with PDA plugs were as control. The experiment was conducted twice. All plants were incubated for 2 d at 15℃ to 25℃ and 90% relative humidity with a 12 h photoperiod/day. Irregularly shaped lesions appeared on the leaves around each of the inoculated sites, but not on control leaves. The pathogens were reisolated and confirmed be R. solani AG1-IB by hyphal fusion and molecular identification tests as previously described, thereby fulfilling Koch's postulates. It has been reported that AG-3, AG-2 (Mercado Cardenas et al. 2012), AG-5 (Wang et al. 2023) and AG-6 (Sun et al. 2022) of R. solani could cause tobacco target spot, but AG-3 is considered the main causal agent (Marleny Gonzalez et al. 2011). To our knowledge, this is the first report of AG1-IB causing tobacco target spot in China and worldwide. The AG1-IB strain has a wide host range including cabbage, mint, lettuce, beans, and rice (Gonzalez et al. 2006). The discovery poses a new challenge for the prevention and control of tobacco target spot, especially when contemplating disease management strategies such as crop rotation and fungicide treatments.

CRISPR/dCas9-Mediated Specific Molecular Assembly Facilitates Genotyping of Mutant Circulating Tumor DNA.

Breakthroughs in circulating tumor DNA (ctDNA) analysis are critical in tumor liquid biopsies but remain a technical challenge due to the double-stranded structure, extremely low abundance, and short half-life of ctDNA. Here, we report an electrochemical CRISPR/dCas9 sensor (E-dCas9) for sensitive and specific detection of ctDNA at a single-nucleotide resolution. The E-dCas9 design harnesses the specific capture and unzipping of target ctDNA by dCas9 to introduce a complementary reporter probe for specific molecular assembly and signal amplification. By efficient homogeneous assembly and interfacial click reaction, the assay demonstrates superior sensitivity (up to 2.86 fM) in detecting single-base mutant ctDNA and a broad dynamic range spanning 6 orders of magnitude. The sensor is also capable of measuring 10 fg/µL of a mutated target in excess of wild-type ones (1 ng/µL), equivalent to probing 0.001% of the mutation relative to the wild type. In addition, our sensor can monitor the dynamic expression of cellular genomic DNA and allows accurate analysis of blood samples from patients with nonsmall cell lung cancer, suggesting the potential of E-dCas9 as a promising tool in ctDNA-based cancer diagnosis.

Adsorption and Sensing of NO2, SO2, and NH3 on a Janus MoSeTe Monolayer Decorated with Transition Metals (Fe, Co, and Ni): A First-Principles Study.

This paper reports the adsorption of toxic gases (NO2, SO2, and NH3) on a MoSeTe structure based on first principles. It was found that the gas (NO2, SO2, and NH3) adsorption on a pure MoSeTe monolayer was weak; however, the adsorption performance of these gas molecules on transition-metal-atom-supported MoSeTe monolayers (TM-MoSeTe) was better than that on pure MoSeTe monolayers. In addition, there was more charge transfer between gas molecules and TM-MoSeTe. By comparing the adsorption energy and charge transfer values, the trend of adsorption energy and charge transfer in the adsorption of NO2 and SO2 was determined to be Fe-MoSeTe > Co-MoSeTe > Ni-MoSeTe. For the adsorption of NH3, the effect trend was as follows: Co-MoSeTe > Ni-MoSeTe > Fe-MoSeTe. Finally, by comparing their response times, the better gas sensor was selected. The Ni-MoSeTe system is suitable for NO2 gas sensors, and the Fe-MoSeTe and Co-MoSeTe systems are suitable for SO2 gas sensors. The Fe-MoSeTe, Co-MoSeTe, and Ni-MoSeTe systems are all suitable for NH3 gas sensors. Janus transition-metal dichalcogenides have the potential to be used as gas-sensing and scavenging materials.

Adsorption of NO2, SO2, H2S, and NH3 on Os-Doped WSe2 Monolayers: A First-Principles Study.

In this study, DFT calculations are used to analyze the adsorption of industrial waste gases (NO2, SO2, H2S, and NH3) on WSe2 monolayers. The adsorption energy, energy band, density of states, charge transfer, and recovery time of the adsorption structures between the target gas molecules and the Os-doped WSe2 are studied. Compared with pure WSe2 monolayer, Os surface bonding doping WSe2 (Os-modified WSe2) and Os doping with Se vacancy of WSe2 (Os-embedded WSe2) exhibit improved gas molecule adsorption ability. Among them, the adsorption energy of the Os-modified WSe2 monolayer on NO2, SO2, H2S, and NH3 is greater than that of the WSe2 monolayer. At the same time, it is proved that the Os-embedded WSe2 can be used as a gas sensor for H2S and NH3 gas molecules at a high temperature.

Prognostic implication of lactic dehydrogenase-to-albumin ratio in critically ill patients with acute kidney injury.

BACKGROUND: No studies have been published on the correlation between lactic dehydrogenase-to-albumin ratio (LAR) and poor prognosis of acute kidney injury (AKI) patients, warranting further research. This analysis sought to investigate the prognostic implication of LAR in critically ill patients with AKI. METHODS: The present study enrolled 11,046 and 5180 adults with AKI from the Medical Information Mart for Intensive Care III (MIMIC III) and MIMIC IV, respectively. Data from MIMIC IV were identified as the training cohort, and those from MIMIC III were identified as the validation cohort. We applied multivariate regression analysis to identify the link between LAR and all-cause mortality. Restricted cubic spline (RCS) was conducted to figure out the correlation between LAR and in-hospital mortality. Furthermore, we carried out stratification analyses to examine if the effects of LAR on in-hospital mortality were consistent across various subclasses. RESULTS: The level of LAR was remarkably higher in the in-hospital non-survivor group (p < 0.001). Furthermore, the increased LAR group presented a remarkably higher rate of in-hospital mortality at AKI stages 1, 2, and 3 compared with the decreased LAR group (all p < 0.001). Multivariate regression analyses exhibited the independent prognostic significance of LAR for all-cause mortality (all p < 0.001). MIMIC III observed concordant results. RCS indicated a non-linear correlation between LAR and in-hospital death (P for non-linearity < 0.001). The relationship between LAR and in-hospital mortality was still significant in patients with various subclasses. CONCLUSIONS: Elevated LAR at admission is a prognostic risk factor for critically ill patients with AKI.

Diagnostic performance of diffusion-weighted imaging versus 18F-FDG PET/CT in differentiating pulmonary lesions: an updated meta-analysis of comparative studies.

OBJECTIVE: To compare the diagnostic accuracy of diffusion-weighted imaging (DWI) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for differentiating pulmonary nodules and masses. METHODS: We systematically searched six databases, including PubMed, EMBASE, the Cochrane Library, and three Chinese databases, to identify studies that used both DWI and PET/CT to differentiate pulmonary nodules. The diagnostic performance of DWI and PET/CT was compared and pooled sensitivity and specificity were calculated along with 95% confidence intervals (CIs). The Quality Assessment of Diagnostic Accuracy Studies 2 was used to assess the quality of the included studies, and STATA 16.0 software was utilized to perform statistical analysis. RESULTS: Overall, 10 studies that enrolled a total of 871 patients with 948 pulmonary nodules were included in this meta-analysis. DWI had greater pooled sensitivity (0.85 [95% CI 0.77-0.90]) and specificity (0.91 [95% CI 0.82-0.96]) than PET/CT (sensitivity, 0.82 [95% CI 0.70-0.90]); specificity, (0.81, [95% CI 0.72-0.87]). The area under the curve of DWI and PET/CT were 0.94 (95% CI 0.91-0.96) and 0.87 (95% CI 0.84-0.90) (Z = 1.58, P > 0.05), respectively. The diagnostic odds ratio of DWI (54.46, [95% CI 17.98-164.99]) was superior to that of PET/CT (15.77, [95% CI 8.19-30.37]). The Deeks' funnel plot asymmetry test showed no publication bias. The Spearman correlation coefficient test revealed no significant threshold effect. Lesion diameter and reference standard could be potential causes for the heterogeneity of both DWI and PET/CT studies, and quantitative or semi-quantitative parameters used would be a potential source of bias for PET/CT studies. CONCLUSION: As a radiation-free technique, DWI may have similar performance compare with PET/CT in differentiating malignant pulmonary nodules or masses from benign ones.

Identification of 3-Methoxyphenylacetic Acid as a Phytotoxin, Produced by Rhizoctonia solani AG-3 TB.

Tobacco target spot disease is caused by Rhizoctonia solani AG-3 TB, which causes serious harm to the quality and yield of tobacco. In this study, thin layer chromatography (TLC), high performance liquid chromatography (HPLC), infrared absorption spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR) were used to purify and identify the potential phytotoxin produced by R. solani AG-3 TB. The result indicated that the purified toxin compound was 3-methoxyphenylacetic acid (3-MOPAA) (molecular formula: C9H10O3). The exogenous purified compound 3-MOPAA was tested, and the results revealed that 3-MOPAA can cause necrosis in tobacco leaves. 3-MOPAA is a derivative of phenylacetic acid (PAA), which should be produced by specific enzymes, such as hydroxylase or methylase, in the presence of PAA. These results enrich the research on the pathogenic phytotoxins of R. solani and provide valuable insights into the pathogenic mechanism of AG-3 TB.

Intravoxel Incoherent Motion Diffusion-Weighted Imaging for Predicting and Monitoring the Response of Anti-Angiogenic Treatment in the Orthotopic Nude Mouse Model of Lung Adenocarcinoma.

BACKGROUND: The treatment efficacy of angiogenesis inhibitor could be underestimated at an early stage based on tumor volume changes. Intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) can quantitatively assess tumors at the cellular level, but it is unclear whether it can provide useful information for assessing treatment response of anti-angiogenic treatment for lung adenocarcinoma. PURPOSE: To determine the use of IVIM-DWI for non-invasive monitoring of the early response to anti-angiogenic treatment in the orthotopic transplantation of lung adenocarcinoma model. STUDY TYPE: Prospective. POPULATION: Thirty-seven nude mice were randomized into two groups: treatment group (received bevacizumab + cisplatin, N = 20) and control group (received saline, N = 17). FIELD STRENGTH/SEQUENCE: Single-shot turbo spin-echo (TSE) IVIM-DWI, TSE T2-weighted imaging at 3.0 T. ASSESSMENT: Tumor volume, IVIM parameters (apparent diffusion coefficient [ADC], diffusivity [D], perfusion fraction [f], and pseudo-diffusion coefficient [D*]) were measured before and 2 hours, 3, 7, 10 and 14 days after treatment. Regions of interest were manually drawn along the inner edge of the tumor by two radiologists with 5 and 10-year experience in magnetic resonance imaging. Pathological examinations (hematoxylin and eosin stain, cluster of differentiation 34) were performed. STATISTICAL TESTS: Kolmogorov-Smirnov test, repeated-measure two-way analysis of variance test, Mann-Whitney U test, Pearson correlation analysis, receiver operating characteristic curve. P < 0.05 was considered statistically significant. RESULTS: The tumor volume of the two groups was significantly different only on day 14 (control group vs. treatment group, 43.15 ± 18.28 mm3 vs. 28.41 ± 1.71 mm3 ). ADC2h , ADC10d , D2h , D7d , D10d , and D14d were significantly higher, while f10d and f14d were significantly lower in the treatment group compared to those of the control group. Both the △ADC2h (r = -0.631) and △D2h (r = -0.700) showed moderate correlations with the relative tumor volume on day 14. DATA CONCLUSION: IVIM has the potential to predict and monitor the early response to anti-angiogenic treatment, earlier than size changes, for lung adenocarcinoma. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 4.

Metabolomics and Cytokine Analysis for Identification of Schizophrenia with Auditory Hallucination.

PURPOSE: To investigate the metabolic profile and biomarkers of schizophrenia with auditory hallucinations (AHs). METHODS: A total of 18 schizophrenic patients with the symptom of pure AHs (pAHs), 28 without AH (nAHs) and 43 age-matched healthy persons (Con) were enrolled in this study. Participants in pAHs and nAHs groups had relapsed into exacerbations of psychosis after self-discontinuing antipsychotics for at least one month; blood samples were drawn prior to restarting anti-psychotic treatment. Participants with history of recreational substance use were excluded. Positive and Negative Syndrome Scale (PANSS) and Auditory Hallucinations Rating Scale (AHRS) were used to assess the clinical mental state of all samples. Enzyme-linked immunosorbent assay (ELISA) was used to estimate the level of cytokines, and metabolomics analysis to identify potential biomarkers and pathways in the three groups. Graphpad 8.0 software was used to calculate the area under the receiver operating characteristic (ROC) curve. The relationship between metabolites and cytokines were determined using correlation analysis. RESULTS: Questionnaire scores showed significant differences in the positive symptom scale and PANSS total between nAHs and pAHs groups. Four cytokines (BDNF, IL-2, NGF-ß and TNF-α) differed significantly among the three groups. Six molecules in the nAHs group (phenylalanine, hippurate, serine, glutamate, valine and cystine) and four in the pAHs group (phenylalanine, serine, glutamate and cystine) were identified as potential biomarkers. In addition, phenylalanine was shown as a potential independent diagnostic biomarker for pAHs. Correlation analysis revealed that cystine and serine were significantly negatively correlated with IL-2 in the pAHs group. CONCLUSIONS: This study revealed the metabolic profile of patients with schizophrenia with AHs and provided new information to support the diagnosis. The identification of unique biomarkers would contribute to objective and reliable diagnoses of patients with schizophrenia with AH.

Evaluation of peripheral nerve acute crush injury in rabbits: comparison among diffusion kurtosis imaging, diffusion tensor imaging and electromyography.

OBJECTIVE: Diffusion kurtosis imaging (DKI) has been proven to provide additional value for assessing many central nervous system diseases compared with conventional diffusion tensor imaging (DTI); however, whether it has the same value in peripheral nerve injury is unclear. This study aimed to investigate the performance of DKI, DTI, and electromyography (EMG) in evaluating peripheral nerve crush injury (PNCI) in rabbits. MATERIALS AND METHODS: A total of 27 New Zealand white rabbits were selected to establish a PNCI model. Longitudinal DTI, DKI, and EMG were evaluated before surgery and 1 day, 3 days, 1 week, 2 weeks, 4 weeks, 6 weeks, and 8 weeks after surgery. At each time point, two rabbits were randomly selected for pathological examination. RESULTS: The results showed that fractional anisotropy (FA) derived from both DKI and DTI demonstrated a significant difference between injured and control nerves at all time points (all P < 0.005) mean kurtosis of the injured nerve was lower than that on the control side after 2-8 weeks (all P < 0.05). No statistically significant difference was found in radial kurtosis, axial kurtosis, and apparent diffusion coefficient at almost every time point. The difference in compound muscle action potential (CMAP) of the bilateral gastrocnemius at each time point was statistically significant (all P < 0.001). CONCLUSIONS: CMAP was a sensitive and reliable method to assess acute PNCI without being affected by perineural edema. DKI may not be superior to DTI in evaluating peripheral nerves, DTI with a shorter scanning time was preferred as an effective choice for evaluating acute peripheral nerve traumatic injury.

Classification of pulmonary lesion based on multiparametric MRI: utility of radiomics and comparison of machine learning methods.

OBJECTIVES: We develop and validate a radiomics model based on multiparametric magnetic resonance imaging (MRI) in the classification of the pulmonary lesion and identify optimal machine learning methods. MATERIALS AND METHODS: This retrospective analysis included 201 patients (143 malignancies, 58 benign lesions). Radiomics features were extracted from multiparametric MRI, including T2-weighted imaging (T2WI), T1-weighted imaging (TIWI), and apparent diffusion coefficient (ADC) map. Three feature selection methods, including recursive feature elimination (RFE), t test, and least absolute shrinkage and selection operator (LASSO), and three classification methods, including linear discriminate analysis (LDA), support vector machine (SVM), and random forest (RF) were used to distinguish benign and malignant pulmonary lesions. Performance was compared by AUC, sensitivity, accuracy, precision, and specificity. Analysis of performance differences in three randomly drawn cross-validation sets verified the stability of the results. RESULTS: For most single MR sequences or combinations of multiple MR sequences, RFE feature selection method with SVM classifier had the best performance, followed by RFE with RF. The radiomics model based on multiple sequences showed a higher diagnostic accuracy than single sequence for every machine learning method. Using RFE with SVM, the joint model of T1WI, T2WI, and ADC showed the highest performance with AUC = 0.88 ± 0.02 (sensitivity 83%; accuracy 82%; precision 91%; specificity 79%) in test set. CONCLUSION: Quantitative radiomics features based on multiparametric MRI have good performance in differentiating lung malignancies and benign lesions. The machine learning method of RFE with SVM is superior to the combination of other feature selection and classifier methods. KEY POINTS: • Radiomics approach has the potential to distinguish between benign and malignant pulmonary lesions. • Radiomics model based on multiparametric MRI has better performance than single-sequence models. • The machine learning methods RFE with SVM perform best in the current cohort.

Electrostatically mediated layer-by-layer assembly of nitrogen-doped graphene/PDDA/gold nanoparticle composites for electrochemical detection of uric acid.

A layer-by-layer self-assembled nitrogen-doped graphene/PDDA/gold nanoparticle (NDG/PDDA/GNP) composite was described. Citrate-stabilizing gold nanoparticle colloids (GNPs) were electrostatically adsorbed onto NDG nanosheets using a cationic polyelectrolyte, polydiallyldimethylammonium (PDDA), as the linker, thereby creating a high-performance electrochemical interface. The morphology and chemical composition were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, infrared spectroscopy, and Raman spectroscopy. Analytical application was manifested by electrochemical sensing of uric acid (UA), a biomarker involved with a variety of clinical diseases. The prepared nanocomposite exhibited noticeable electroactivity to uric acid oxidation and can give effective peak separation with ascorbic acid and dopamine. Additionally, the nanocomposite practically averted from other potentially interferents including glucose, urea, and serotonin, thus allowing selective voltammetric detection of UA in the biological matrix. Under the optimal condition, peak currents measured by differential pulse voltammetry were proportional to UA concentrations in the range of 0.5~100 µM (R2 = 0.998), with the detection limit of 53 nM. The NDG/PDDA/GNP nanocomposite as presented herein holds potential for aiding the diagnosis of UA-associated diseases and should be a new opportunity for biochemical analysis and biosensing applications. Graphical abstract.

Intravoxel Incoherent Motion Diffusion-Weighted Imaging of Lung Cancer: Comparison Between Turbo Spin-Echo and Echo-Planar Imaging.

OBJECTIVE: The aim of the study was to compare intravoxel incoherent motion diffusion-weighted imaging (DWI) for evaluating lung cancer using single-shot turbo spin-echo (TSE) and single-shot echo-planar imaging (EPI) in a 3T MR system. METHODS: Both single-shot TSE-DWI and single-shot EPI-DWI were scanned twice respectively for 15 patients with lung cancer. Distortion ratio, signal-to-noise ratio, and contrast-to-noise ratio were compared between the 2 techniques. The Bland-Altman analysis was performed to analyze reproducibility between the parameters of TSE-DWI and EPI-DWI. Short-term test-retest repeatability, as well as interobserver agreement, was evaluated using the coefficient of variation (CV) and the intraclass correlation coefficient (ICC). RESULT: Turbo spin-echo DWI has lower signal-to-noise ratio and similar contrast-to-noise ratio compared with EPI-DWI. Distortion ratio of TSE-DWI was significantly smaller than that of EPI-DWI. The apparent diffusion coefficient (ADC) and true diffusivity (D) of TSE-DWI showed higher values than those of EPI-DWI. The Bland-Altman analysis showed unacceptable limits of agreement between these 2 sequences. Test-retest repeatability was good for ADC and D of EPI-DWI (CV, 14.11%-16.60% and 17.08%-19.53%) and excellent for ADC and D of TSE-DWI (CV, 4.8%-6.19% and 6.05%-8.71%), but relatively poor for perfusion fraction (f) and pseudo-diffusion coefficient (D*) (CV, 25.95%-27.70% and 56.92%-71.84% for EPI, 23.67%-28.67% and 60.85%-70.17% for TSE). For interobserver agreement, both techniques were good to excellent in ADC and D (The lower limit of 95% confidence interval for ICC was almost all greater than 0.75), whereas D* and f had higher interobserver variabilities with D* of TSE-DWI showing poorest reproducibility (ICC, -0.27 to 0.12). CONCLUSIONS: Lung DWI or IVIM using TSE could provide distortion-free images and improve the test-retest robustness of ADC and D as compared with EPI-DWI; however, it might exert a negative effect on perfusion parameter D*.

Ratiometric fluorescent nanoprobe based on CdTe/SiO2/folic acid/silver nanoparticles core-shell-satellite assembly for determination of 6-mercaptopurine.

A sensitive and robust fluorescent assay of 6-MP is described which relies on the facile assembly of a fluorescence nanoprobe by design of silica nanosphere encapsulated CdTe quantum dots (CdTe QDs) as scaffold, coupling with chemically tethered folic acid (FA)-protected silver nanoparticles (AgNPs) that function as responsive element. In this way a stable ternary core-shell-satellite nanostructure with dual-emission signals can be established. On binding to the target molecules, 6-MP, FA molecules initially occupied by AgNPs are liberated to give dose-dependent fluorescence emission, which can further form a self-calibration ratiometric fluorescence assay using CdTe QDs as an internal reference. The nanoprobe color vividly changes from red to blue, enabling the direct visual detection. The linear concentration range is 0.15~50 µM with the detection limit of 67 nM. By virtue of the favorable selectivity and robust assays, the nanoprobe was applied to 6-MP detection in urine samples, with recoveries from 97.3 to 106% and relative standard deviations (RSD) less than 5%. Graphical abstract.

Differentiating between malignant and benign solid solitary pulmonary lesions: are intravoxel incoherent motion and diffusion kurtosis imaging superior to conventional diffusion-weighted imaging?

OBJECTIVE: To quantitatively compare the diagnostic values of various diffusion parameters obtained from mono- and biexponential diffusion-weighted imaging (DWI) models and diffusion kurtosis imaging (DKI) in differentiating between benign and malignant solitary pulmonary lesions (SPLs). METHODS: Multiple b-value DWIs and DKIs were performed in 89 patients with SPL by using a 3-T magnetic resonance (MR) imaging unit. The apparent diffusion coefficient (ADC) of various b-value sets, true diffusivity (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), apparent diffusional kurtosis (Kapp), and kurtosis-corrected diffusion coefficient (Dapp) were calculated and compared between the malignant and benign groups using a Mann-Whitney U test. Receiver-operating characteristic analysis was performed for all parameters. RESULT: The ADC(0, 150) values of malignant tumors were lower than those of the benign group (p = 0.01). The ADC(0, 300), ADC(0, 500), ADC(0, 600), ADC(0, 800), ADC(0, 1000), ADCtotal, D, and Dapp of malignant tumors were significantly lower than those of benign lesions (all p < 0.001). D*, f, and Kapp showed no statistically significant differences between the two groups. ADCtotal showed the highest area under the curve (AUC = 0.862), followed by ADC(0, 800)(AUC = 0.844), ADC(0, 600)(AUC = 0.843), D(AUC = 0.834), ADC(0, 1000)(AUC = 0.834) and ADC(0, 500)(AUC = 0.824), Dapp(AUC = 0.796), and ADC(0, 300) (AUC = 0.773). However, the difference in diagnostic efficacy among these parameters was not statistically significant (p > 0.05). CONCLUSION: Intravoxel incoherent motion (IVIM) and DKI-derived parameters have similar performance compared with conventional ADC in differentiating SPLs. KEY POINTS: • Mono- and biexponential DWI and DKI are feasible for differentiating SPLs. • ADC (0, ≥500) has better performance than ADC (0, <500) in assessing SPLs. • IVIM and DKI have similar performance compared with conventional DWI in differentiating SPLs.

Exploring transcription factors reveals crucial members and regulatory networks involved in different abiotic stresses in Brassica napus L.

BACKGROUND: Brassica napus (B. napus) encompasses diverse transcription factors (TFs), but thorough identification and characterization of TF families, as well as their transcriptional responsiveness to multifarious stresses are still not clear. RESULTS: Totally 2167 TFs belonging to five families were genome-widely identified in B. napus, including 518 BnAP2/EREBPs, 252 BnbZIPs, 721 BnMYBs, 398 BnNACs and 278 BnWRKYs, which contained some novel members in comparison with existing results. Sub-genome distributions of BnAP2/EREBPs and BnMYBs indicated that the two families might have suffered from duplication and divergence during evolution. Synteny analysis revealed strong co-linearity between B. napus and its two ancestors, although chromosomal rearrangements have occurred and 85 TFs were lost. About 7.6% and 9.4% TFs of the five families in B. napus were novel genes and conserved genes, which both showed preference on the C sub-genome. RNA-Seq revealed that more than 80% TFs were abiotic stress inducible and 315 crucial differentially expressed genes (DEGs) were screened out. Network analysis revealed that the 315 DEGs are highly co-expressed. The homologous gene network in A. thaliana revealed that a considerable amount of TFs could trigger the differential expression of targeted genes, resulting in a complex clustered network with clusters of genes responsible for targeted stress responsiveness. CONCLUSIONS: We identified and characterized five TF families in B. napus. Some crucial members and regulatory networks involved in different abiotic stresses have been explored. The investigations deepen our understanding of TFs for stress tolerance in B. napus.