Molecular Architecture of the SARS-CoV-2 Virus.

SARS-CoV-2 is an enveloped virus responsible for the COVID-19 pandemic. Despite recent advances in the structural elucidation of SARS-CoV-2 proteins, the detailed architecture of the intact virus remains to be unveiled. Here we report the molecular assembly of the authentic SARS-CoV-2 virus using cryoelectron tomography (cryo-ET) and subtomogram averaging (STA). Native structures of the S proteins in pre- and postfusion conformations were determined to average resolutions of 8.7-11 Å. Compositions of the N-linked glycans from the native spikes were analyzed by mass spectrometry, which revealed overall processing states of the native glycans highly similar to that of the recombinant glycoprotein glycans. The native conformation of the ribonucleoproteins (RNPs) and their higher-order assemblies were revealed. Overall, these characterizations revealed the architecture of the SARS-CoV-2 virus in exceptional detail and shed light on how the virus packs its ∼30-kb-long single-segmented RNA in the ∼80-nm-diameter lumen.

Honey bees switch mechanisms to drink deep nectar efficiently.

The feeding mechanisms of animals constrain the spectrum of resources that they can exploit profitably. For floral nectar eaters, both corolla depth and nectar properties have marked influence on foraging choices. We report the multiple strategies used by honey bees to efficiently extract nectar at the range of sugar concentrations and corolla depths they face in nature. Honey bees can collect nectar by dipping their hairy tongues or capillary loading when lapping it, or they can attach the tongue to the wall of long corollas and directly suck the nectar along the tongue sides. The honey bee feeding apparatus is unveiled as a multifunctional tool that can switch between lapping and sucking nectar according to the instantaneous ingesting efficiency, which is determined by the interplay of nectar-mouth distance and sugar concentration. These versatile feeding mechanisms allow honey bees to extract nectar efficiently from a wider range of floral resources than previously appreciated and endow them with remarkable adaptability to diverse foraging environments.

Effect of M2-macrophage treated lymphatic endothelial cells on angiogenesis that promoted osteointegration.

Early vascularization plays an essential role during the whole process in bone regeneration because of the function of secreting cytokines, transporting nutrients and metabolic wastes. As the preliminary basis of bone repair, angiogenesis is regulated by immune cells represented by macrophages to a great extent. However, with the discovery of the endolymphatic circulation system inside bone tissue, the role of vascularization became complicated and confusing. Herein, we developed a macrophage/lymphatic endothelial cells (LECs)/human umbilical vein endothelial cells (HUVECs) co-culture system to evaluate the effect of macrophage treated lymphatic endothelial cells on angiogenesis in vitro and in vivo. In this study, we collected the medium from macrophage (CM) for LECs culture. We found that CM2 could promote the expression of LECs markers and migration ability, which indicated the enhanced lymphogenesis. In addition, the medium from LECs was collected for culturing HUVECs. The CM2-treated LECs showed superior angiogenesis property including the migration capacity and expression of angiogenetic markers, which suggested the superior vascularization. Rat femoral condyle defect model was applied to confirm the hypothesis in vivo. Generally, M2-macrophage treated LECs showed prominent angiogenetic potential coupling with osteogenesis.

Highly active repeat-mediated recombination in the mitogenome of the aquatic grass Hygroryza aristata.

BACKGROUND: Floating bamboo (Hygroryza aristata) is an endangered species with a narrow native distribution and is renowned for its unique aesthetic qualities, which holds significant ecological and ornamental value. However, the lack of genetic information research, with only one complete plastome available, significantly hampers conservation efforts and further research for this species. RESULTS: In this research, we sequenced and assembled the organelle genomes of floating bamboo, including the mitogenome (587,847 bp) and plastome (135,675 bp). The mitogenome can recombine into various configurations, which are mediated by 25 repeat pairs (13 SRs, 6 MRs, 1 LR, and 5 CRs). LR1 and SR5 are particularly notable as they have the ability to combine with other contigs, forming complex repeat units that facilitate further homologous recombination. The rate of homologous recombination varies significantly among species, yet there is still a pronounced positive correlation observed between the length of these repeat pairs and the rate of recombination they mediate. The mitogenome integrates seven intact protein-coding genes from the chloroplast. The codon usage patterns in both organelles are similar, with a noticeable bias towards C and T on the third codon. The gene map of Poales shows the entire loss of rpl6, succinate dehydrogenase subunits (sdh3 and sdh4). Additionally, the BOP clade retained more variable genes compared to the PACMAD clade. CONCLUSIONS: We provided a high-quality and well-annotated mitogenome for floating bamboo and demonstrated the presence of diverse configurations. Our study has revealed the correlation between repeat length and their corresponding recombination rate despite variations among species. Although the mitogenome can potentially exist in the form of a unicircular in vivo, this occurrence is rare and may not be stable.

CwJAZ4/9 negatively regulates jasmonate-mediated biosynthesis of terpenoids through interacting with CwMYC2 and confers salt tolerance in Curcuma wenyujin.

Plant JASMONATE ZIM-DOMAIN (JAZ) genes play crucial roles in regulating the biosynthesis of specialized metabolites and stressful responses. However, understanding of JAZs controlling these biological processes lags due to numerous JAZ copies. Here, we found that two leaf-specific CwJAZ4/9 genes from Curcuma wenyujin are strongly induced by methyl-jasmonate (MeJA) and negatively correlated with terpenoid biosynthesis. Yeast two-hybrid, luciferase complementation imaging and in vitro pull-down assays confirmed that CwJAZ4/9 proteins interact with CwMYC2 to form the CwJAZ4/9-CwMYC2 regulatory cascade. Furthermore, transgenic hairy roots showed that CwJAZ4/9 acts as repressors of MeJA-induced terpenoid biosynthesis by inhibiting the terpenoid pathway and jasmonate response, thus reducing terpenoid accumulation. In addition, we revealed that CwJAZ4/9 decreases salt sensitivity and sustains the growth of hairy roots under salt stress by suppressing the salt-mediated jasmonate responses. Transcriptome analysis for MeJA-mediated transgenic hairy root lines further confirmed that CwJAZ4/9 negatively regulates the terpenoid pathway genes and massively alters the expression of genes related to salt stress signaling and responses, and crosstalks of multiple phytohormones. Altogether, our results establish a genetic framework to understand how CwJAZ4/9 inhibits terpenoid biosynthesis and confers salt tolerance, which provides a potential strategy for producing high-value pharmaceutical terpenoids and improving resistant C. wenyujin varieties by a genetic approach.

Association between atherogenic index of plasma control level and incident cardiovascular disease in middle-aged and elderly Chinese individuals with abnormal glucose metabolism.

BACKGROUND: The atherogenic index of plasma (AIP) and cardiovascular disease (CVD) in participants with abnormal glucose metabolism have been linked in previous studies. However, it was unclear whether AIP control level affects the further CVD incidence among with diabetes and pre-diabetes. Therefore, our study aimed to investigate the association between AIP control level with risk of CVD in individuals with abnormal glucose metabolism. METHODS: Participants with abnormal glucose metabolism were included from the China Health and Retirement Longitudinal Study. CVD was defined as self-reporting heart disease and/or stroke. Using k-means clustering analysis, AIP control level, which was the log-transformed ratio of triglyceride to high-density lipoprotein cholesterol in molar concentration, was divided into five classes. The association between AIP control level and incident CVD among individuals with abnormal glucose metabolism was investigated multivariable logistic regression analysis and application of restricted cubic spline analysis. RESULTS: 398 (14.97%) of 2,659 participants eventually progressed to CVD within 3 years. After adjusting for various confounding factors, comparing to class 1 with the best control of the AIP, the OR for class 2 with good control was 1.31 (95% CI, 0.90-1.90), the OR for class 3 with moderate control was 1.38 (95% CI, 0.99-1.93), the OR for class 4 with worse control was 1.46 (95% CI, 1.01-2.10), and the OR for class 5 with consistently high levels was 1.56 (95% CI, 1.03-2.37). In restricted cubic spline regression, the relationship between cumulative AIP index and CVD is linear. Further subgroup analysis demonstrated that the similar results were observed in the individuals with agricultural Hukou, history of smoking, diastolic blood pressure ≥ 80mmHg, and normal body mass index. In addition, there was no interaction between the AIP control level and the subgroup variables. CONCLUSIONS: In middle-aged and elderly participants with abnormal glucose metabolism, constant higher AIP with worst control may have a higher incidence of CVD. Monitoring long-term AIP change will contribute to early identification of high risk of CVD among individuals with abnormal glucose metabolism.

Strongly Interacting Bose-Fermi Mixtures: Mediated Interaction, Phase Diagram, and Sound Propagation.

Motivated by recent surprising experimental findings, we develop a strong-coupling theory for Bose-Fermi mixtures capable of treating resonant interspecies interactions while satisfying the compressibility sum rule. We show that the mixture can be stable at large interaction strengths close to resonance, in agreement with the experiment, but at odds with the widely used perturbation theory. We also calculate the sound velocity of the Bose gas in the ^{133}Cs-^{6}Li mixture, again finding good agreement with the experimental observations both at weak and strong interactions. A central ingredient of our theory is the generalization of a fermion mediated interaction to strong Bose-Fermi scatterings and to finite frequencies. This further leads to a predicted hybridization of the sound modes of the Bose and Fermi gases, which can be directly observed using Bragg spectroscopy.

Impact of treatment interval between neoadjuvant immunochemotherapy and surgery in lung squamous cell carcinoma.

OBJECTIVE: The optimal timing for surgery following neoadjuvant immunochemotherapy for lung squamous cell carcinoma appears to be a topic of limited data. Many clinical studies lack stringent guidelines regarding this timing. The objective of this study is to explore the effect of the interval between neoadjuvant immunochemotherapy and surgery on survival outcomes in patients with lung squamous cell carcinoma. METHODS: This study conducted a retrospective analysis of patients with lung squamous cell carcinoma who underwent neoadjuvant immunochemotherapy between January 2019 and October 2022 at The First Affiliated Hospital, Zhejiang University School of Medicine. Patients were divided into two groups based on the treatment interval: ≤33 days and > 33 days. The primary observational endpoints of the study were Disease-Free Survival (DFS) and Overall Survival (OS). Secondary observational endpoints included Objective response rate (ORR), Major Pathological Response (MPR), and Pathological Complete Remission (pCR). RESULTS: Using the Kaplan-Meier methods, the ≤ 33d group demonstrated a superior DFS curve compared to the > 33d group (p = 0.0015). The median DFS for the two groups was 952 days and 590 days, respectively. There was no statistical difference in the OS curves between the groups (p = 0.66), and the median OS was not reached for either group. The treatment interval did not influence the pathologic response of the tumor or lymph nodes. CONCLUSIONS: The study observed that shorter treatment intervals were associated with improved DFS, without influencing OS, pathologic response, or surgical safety. Patients should avoid having a prolonged treatment interval between neoadjuvant immunochemotherapy and surgery.

Second-Order Motion-Compensated Echo-Planar Cardiac Diffusion-Weighted MRI: Usefulness of Compressed Sensitivity Encoding.

BACKGROUND: Cardiac diffusion-weighted imaging (DWI) using second-order motion-compensated spin echo (M2C) can provide noninvasive in-vivo microstructural assessment, but limited by relatively low signal-to-noise ratio (SNR). Echo-planar imaging (EPI) with compressed sensitivity encoding (EPICS) could address these issues. PURPOSE: To combine M2C DWI and EPCIS (M2C EPICS DWI), and compare image quality for M2C DWI. STUDY TYPE: Prospective. POPULATION: Ten ex-vivo hearts, 10 healthy volunteers (females, 5 [50%]; mean ± SD of age, 25 ± 4 years), and 12 patients with diseased hearts (female, 1 [8.3%]; mean ± SD of age, 44 ± 16 years; including coronary artery heart disease, congenital heart disease, dilated cardiomyopathy, amyloidosis, and myocarditis). FIELD STRENGTH/SEQUENCE: 3-T, M2C EPICS DWI, and M2C DWI. ASSESSMENT: The apparent SNR (aSNR) and the rating scores were used to evaluate and compared image quality of all three groups. The aSNR was calculated using aSNR = Mean intensity myocardium / Standard deviation myocardium $$ \mathrm{aSNR}={\mathrm{Mean}\ \mathrm{intensity}}_{\mathrm{myocardium}}/{\mathrm{Standard}\ \mathrm{deviation}}_{\mathrm{myocardium}} $$ , and the myocardium was segmented manually. Three observers independently rated subjective image quality using a 5-point Likert scale. STATISTICAL TESTS: Bland-Altman analysis and paired t-tests. The threshold for statistical significance was set at P < 0.05. RESULTS: In healthy volunteers, the aSNR with a b-value of 450 s/mm2 acquired by M2C EPICS DWI was significantly higher than M2C DWI at in-plane resolutions of 3.0 × 3.0, 2.5 × 2.5, and 2.0 × 2.0 mm2. In patients with diseased hearts, the aSNR ofM2C EPICS DWI was also significantly higher than that for M2C DWI (bias of M2C EPICS-M2C = 1.999, 95% limits of agreement, 0.362 to 3.636; mean ± SD, 7.80 ± 1.37 vs. 5.80 ± 0.81). The ADC values of M2C EPICS was significantly higher than M2C DWI in in-vivo hearts. Over 80% of the images with rating scores for M2C EPICS DWI were higher than M2C DWI in in-vivo hearts. DATA CONCLUSION: Cardiac imaging by M2C EPICS DWI may demonstrate better overall image quality and higher aSNR than M2C DWI. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 1.

Digital exclusion and cognitive impairment in older people: findings from five longitudinal studies.

OBJECTIVES: Older people are more likely to have digital exclusion, which is associated with poor health. This study investigated the relationship between digital exclusion and cognitive impairment in older adults from 23 countries across five longitudinal surveys. DESIGN AND MEASUREMENTS: Digital exclusion is defined as self-reported non-use of the Internet. We assessed cognitive impairment on three dimensions: orientation, memory, and executive function. We used generalized estimation equations fitting binary logistic regression with exchangeable correlations to study the relationship between digital exclusion and cognitive impairment, and apply the minimum sufficiently adjusted set of causally directed acyclic graphs as the adjusted variable. SETTING AND PARTICIPANTS: We pooled a nationally representative sample of older adults from five longitudinal studies, including the China Health and Retirement Longitudinal study (CHARLS), the English Longitudinal Study of Ageing (ELSA), the Health and Retirement Study (HRS), the Mexican Health and Ageing Study (MHAS) and the Survey of Health, Ageing and Retirement in European (SHARE). RESULTS: We included 62,413 participants from five longitudinal studies. Digital exclusion varied by country, ranging from 21.69% (SHARE) in Denmark to 97.15% (CHARLS) in China. In the original model, digital exclusion was significantly associated with cognitive impairment in all five studies. In the adjusted model, these associations remained statistically significant: CHARLS (Odds ratio [OR] = 2.81, 95% confidence interval [CI] 1.84-4.28, ELSA (1.92 [1.70-2.18]), HRS(2.48[2.28-2.71), MHAS (1.92 [1.74-2.12]), and SHARE (2.60 [2.34-2.88]). CONCLUSION: Our research shows that a significant proportion of older people suffer from digital exclusion, especially in China. Digital exclusion was positively correlated with cognitive impairment. These findings suggest that digital inclusion could be an important strategy to improve cognitive function and reduce the risk of cognitive impairment in older adults.

Relative Motion Estimation Algorithm for Noncooperative Targets Considering Multiple Solutions of Rotational Parameters.

On-orbit servicing using a space robot is gaining popularity among the space community for both economic and safety aspects. In particular, the estimation of the relative motion of a noncooperative target is a challenging problem. This study presents a relative motion estimation scheme based on stereovision for noncooperative targets considering multiple solutions of rotational parameters. Specifically, the mass distribution of the target is identified based on the least-square method and the principle of conservation of angular momentum. Then, the determination of a unique principal axis coordinate frame of the target is employed to resolve the multiple-solution problem. In addition, an EKF (extended Kalman filter)-based filter with global observability is designed to estimate the full motion states and inertia parameters of the target. The convergence performance of the proposed method is verified by numerical simulation. The results also demonstrate that the method is robust to occlusion.

Optical Control of Protein Functions via Genetically Encoded Photocaged Aspartic Acids.

Site-specific protein decaging by light has become an effective approach for in situ manipulation of protein activities in a gain-of-function fashion. Although successful decaging of amino acid side chains of Lys, Tyr, Cys, and Glu has been demonstrated, this strategy has not been extended to aspartic acid (Asp), an essential amino acid residue with a range of protein functions and protein-protein interactions. We herein reported a genetically encoded photocaged Asp and applied it to the photocontrolled manipulation of a panel of proteins including firefly luciferase, kinases (e.g., BRAF), and GTPase (e.g., KRAS) as well as mimicking the in situ phosphorylation event on kinases. As a new member of the increasingly expanded amino acid-decaging toolbox, photocaged Asp may find broad applications for gain-of-function study of diverse proteins as well as biological processes in living cells.

IMPULSED model based cytological feature estimation with U-Net: Application to human brain tumor at 3T.

PURPOSE: This work introduces and validates a deep-learning-based fitting method, which can rapidly provide accurate and robust estimation of cytological features of brain tumor based on the IMPULSED (imaging microstructural parameters using limited spectrally edited diffusion) model fitting with diffusion-weighted MRI data. METHODS: The U-Net was applied to rapidly quantify extracellular diffusion coefficient (Dex ), cell size (d), and intracellular volume fraction (vin ) of brain tumor. At the training stage, the image-based training data, synthesized by randomizing quantifiable microstructural parameters within specific ranges, was used to train U-Net. At the test stage, the pre-trained U-Net was applied to estimate the microstructural parameters from simulated data and the in vivo data acquired on patients at 3T. The U-Net was compared with conventional non-linear least-squares (NLLS) fitting in simulations in terms of estimation accuracy and precision. RESULTS: Our results confirm that the proposed method yields better fidelity in simulations and is more robust to noise than the NLLS fitting. For in vivo data, the U-Net yields obvious quality improvement in parameter maps, and the estimations of all parameters are in good agreement with the NLLS fitting. Moreover, our method is several orders of magnitude faster than the NLLS fitting (from about 5 min to <1 s). CONCLUSION: The image-based training scheme proposed herein helps to improve the quality of the estimated parameters. Our deep-learning-based fitting method can estimate the cell microstructural parameters fast and accurately.

Development of a multi-recombinase polymerase amplification assay for rapid identification of COVID-19, influenza A and B.

The coronavirus disease 2019 (COVID-19) pandemic caused extensive loss of life worldwide. Further, the COVID-19 and influenza mix-infection had caused great distress to the diagnosis of the disease. To control illness progression and limit viral spread within the population, a real-time reverse-transcription PCR (RT-PCR) assay for early diagnosis of COVID-19 was developed, but detection was time-consuming (4-6 h). To improve the diagnosis of COVID-19 and influenza, we herein developed a recombinase polymerase amplification (RPA) method for simple and rapid amplification of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19 and Influenza A (H1N1, H3N2) and B (influenza B). Genes encoding the matrix protein (M) for H1N1, and the hemagglutinin (HA) for H3N2, and the polymerase A (PA) for Influenza B, and the nucleocapsid protein (N), the RNA-dependent-RNA polymerase (RdRP) in the open reading frame 1ab (ORF1ab) region, and the envelope protein (E) for SARS-CoV-2 were selected, and specific primers were designed. We validated our method using SARS-CoV-2, H1N1, H3N2 and influenza B plasmid standards and RNA samples extracted from COVID-19 and Influenza A/B (RT-PCR-verified) positive patients. The method could detect SARS-CoV-2 plasmid standard DNA quantitatively between 102 and 105 copies/ml with a log linearity of 0.99 in 22 min. And this method also be very effective in simultaneous detection of H1N1, H3N2 and influenza B. Clinical validation of 100 cases revealed a sensitivity of 100% for differentiating COVID-19 patients from healthy controls when the specificity was set at 90%. These results demonstrate that this nucleic acid testing method is advantageous compared with traditional PCR and other isothermal nucleic acid amplification methods in terms of time and portability. This method could potentially be used for detection of SARS-CoV-2, H1N1, H3N2 and influenza B, and adapted for point-of-care (POC) detection of a broad range of infectious pathogens in resource-limited settings.

MR-Nucleomics: The study of pathological cellular processes with multinuclear magnetic resonance spectroscopy and imaging in vivo.

Clinical medicine has experienced a rapid development in recent decades, during which therapies targeting specific cellular signaling pathways, or specific cell surface receptors, have been increasingly adopted. While these developments in clinical medicine call for improved precision in diagnosis and treatment monitoring, modern medical imaging methods are restricted mainly to anatomical imaging, lagging behind the requirements of precision medicine. Although positron emission tomography and single photon emission computed tomography have been used clinically for studies of metabolism, their applications have been limited by the exposure risk to ionizing radiation, the subsequent limitation in repeated and longitudinal studies, and the incapability in assessing downstream metabolism. Magnetic resonance spectroscopy (MRS) or spectroscopic imaging (MRSI) are, in theory, capable of assessing molecular activities in vivo, although they are often limited by sensitivity. Here, we review some recent developments in MRS and MRSI of multiple nuclei that have potential as molecular imaging tools in the clinic.

Normal Values of Magnetic Resonance T1ρ Relaxation Times in the Adult Heart at 1.5 T MRI.

BACKGROUND: T1ρ mapping is a new quantitative MRI technique in recent years. In order to use T1ρ mapping as a noncontrast method to assess myocardial fibrosis, it is necessary to establish a range of normal values. PURPOSE: To establish a potential normal range of cardiac T1ρ values in healthy adults and to explore the influence of slice location and gender on T1ρ values. STUDY TYPE: Prospective. POPULATION: A total of 57 healthy volunteers without cardiovascular risk factors (age 26.7 ± 11.8 years; 29 males). FIELD STRENGTH/SEQUENCE: 1.5 T; modified Look-Locker inversion recovery (MOLLI) (T1 mapping), multiecho gradient-spin-echo (GraSE) (T2 mapping) and T1ρ -prepared steady-state free precession (T1ρ mapping) sequences. ASSESSMENT: Basal, mid, and apical short-axis left ventricular T1 , T2 , and T1ρ maps were acquired. T1ρ maps at spin-locking frequencies of 5 and 400 Hz were subtracted to create myocardial fibrosis index (mFI) maps. Slice-average and global average T1 , T2 , T1ρ , and mFI values were determined. STATISTICAL TESTS: Shapiro-Wilk test, Independent t-test, ANOVA test, Pearson correlation coefficient (r). SIGNIFICANCE: P value < 0.05. RESULTS: The global average values of T1 , T2 , T1ρ, and mFI were 1053 ± 34 msec, 51.9 ± 2.3 msec, 47.9 ± 2.8 msec, and 4.4 ± 1.6 msec. T1ρ values showed a significant gradual increase from the basal slice to the apical slice of the heart (basal 46.5 ± 2.7 msec, mid 48.0 ± 2.9 msec, apical 49.2 ± 3.3 msec). The T1ρ and mFI values of females (49.7 ± 2.4 msec and 5.1 ± 1.2 msec, respectively) were significantly higher than those of males (46.2 ± 1.9 msec and 3.7 ± 1.7 msec, respectively). In addition, there was a moderate positive correlation between global T1ρ values and global T1 values (r = 0.44, P < 0.05) and a moderate positive correlation between global T1ρ values and global T2 values (r = 0.42, P < 0.05). DATA CONCLUSION: In this study, the global T1ρ values of healthy adults' hearts were 47.9 ± 2.8 msec. This study found that gender and slice location of myocardium can affect the T1ρ values. EVIDENCE LEVEL: 4 TECHNICAL EFFICACY: Stage 1.

Rapid manoeuvre of fan worms (Annelida: Sabellidae) through tubes.

Multiple variables determine the success of an escape response of an animal, and the rapidity of the escape manoeuvre is often the most important. Fan worms (Annelida: Sabellidae) can rapidly withdraw their tentacles, which are covered in heavily ciliated ramifications called pinnules, into their tubes to protect them from approaching threats. Here, we explore the dynamic and mechanistic features behind this escape manoeuvre. The escape responses of fan worms were recorded by high-speed videography and quantified by computerized motion analysis, showing an ultrahigh retraction speed of 272±135 mm s-1 (8±4 body lengths s-1). We found that fan worms possess powerful muscle-driven systems, which can generate contractive forces up to 36 times their body weight. In order to achieve these rapid, forceful movements through seawater without damaging their tentacles, fan worms have developed functional morphological adaptations to reduce fluidic drag, including the flattening of their radiolar pinnules and the deformation of bodily segmental ridges. Our hydrodynamic models indicate that these mechanical processes can decrease fluidic drag by 47%, trapped mass by 75% and friction coefficient by 89%. These strategies allow fan worms to execute rapid escape responses and could inspire the design of fast in-pipe robots.

Multiparametric cardiovascular magnetic resonance characteristics and dynamic changes in asymptomatic heart-transplanted patients.

OBJECTIVES: To describe the dynamic changes in cardiac deformation and tissue characteristics using cardiac magnetic resonance (CMR) in asymptomatic patients during 12 months after heart transplantation (HT). METHODS: From April 2020 to January 2021, 21 consecutive HT patients without clinical symptoms were included in this prospective study. Multiparametric CMR was performed at 3, 6, and 12 months after HT. Twenty-five healthy volunteers served as controls. RESULTS: During follow-up, a decline in left ventricular (LV) global radial strain (GRS) (p = 0.020) and right ventricular (RV) global longitudinal strain (GLS) (p < 0.001) and an increase in post-contrast T1 (p = 0.024) and T2 (p < 0.001) in asymptomatic HT patients occurred at 3 months, which normalized at 6 months postoperatively, compared with those in healthy controls. A decline in LVGLS (p < 0.001) and LV global circumferential strain (GCS) (p < 0.001) and an increase in native T1 (p < 0.001), T2 (p < 0.001), and extracellular volume (ECV) (p < 0.001) occurred at 3 months. Although most parameters improved gradually, LVGLS, native T1, and ECV remained abnormal compared with those in healthy controls at 12 months; only T2 and LVGCS were normalized at 6 months and 12 months, respectively. ECV was significantly correlated with LVGLS, LVGCS, and LVGRS. CONCLUSION: Cardiac deformation and tissue characteristics were abnormal early after HT, although the patients were clinically asymptomatic. The dynamic changes in CMR characteristics demonstrate a gradual recovery of myocardial injury associated with transplantation during the first 12 months after HT. KEY POINTS: • Multiparametric CMR can detect the dynamic changes of transplantation-associated myocardial injury. • Post-contrast T1, T2, LVGRS, and RVGLS values are normalized at 6 months after HT. • Native T1, ECV, and LVGLS values remain abnormal compared with those in healthy controls at 12 months after HT.

Feasibility of accelerated non-contrast-enhanced whole-heart bSSFP coronary MR angiography by deep learning-constrained compressed sensing.

OBJECTIVES: To examine a compressed sensing artificial intelligence (CSAI) framework to accelerate image acquisition in non-contrast-enhanced whole-heart bSSFP coronary magnetic resonance (MR) angiography. METHODS: Thirty healthy volunteers and 20 patients with suspected coronary artery disease (CAD) scheduled for coronary computed tomography angiography (CCTA) were enrolled. Non-contrast-enhanced coronary MR angiography was performed with CSAI, compressed sensing (CS), and sensitivity encoding (SENSE) methods in healthy participants and with CSAI in patients. Acquisition time, subjective image quality score, and objective image quality measurement (blood pool homogeneity, signal-to-noise ratio [SNR], and contrast-to-noise ratio [CNR]) were compared among the three protocols. The diagnostic performance of CASI coronary MR angiography for predicting significant stenosis (≥ 50% diameter stenosis) on CCTA was evaluated. The Friedman test was performed to compare the three protocols. RESULTS: Acquisition time was significantly shorter in the CSAI and CS groups than in the SENSE group (10.2 ± 3.2 min vs. 10.9 ± 2.9 min vs. 13.0 ± 4.1 min, p < 0.001). However, the CSAI approach had the highest image quality scores, blood pool homogeneity, mean SNR value, and mean CNR value (all p < 0.001) compared with the CS and SENSE approaches. The sensitivity, specificity, and accuracy of CSAI coronary MR angiography per patient were 87.5% (7/8), 91.7% (11/12), and 90.0% (18/20); those per vessel were 81.8% (9/11), 93.9% (46/49), and 91.7% (55/60); and those per segment were 84.6% (11/13), 98.0% (244/249), and 97.3% (255/262), respectively. CONCLUSIONS: CSAI yielded superior image quality within a clinically feasible acquisition time in healthy participants and patients with suspected CAD. CLINICAL RELEVANCE STATEMENT: The non-invasive and radiation-free CSAI framework could be a promising tool for rapid screening and comprehensive examination of the coronary vasculature in patients with suspected CAD. KEY POINTS: • This prospective study showed that CSAI enables a reduction in acquisition time by 22% with superior diagnostic image quality compared with the SENSE protocol. • CSAI replaces the wavelet transform with a CNN as a sparsifying transform in the CS algorithm, achieving high coronary MR image quality with reduced noise. • CSAI achieved per-patient sensitivity of 87.5% (7/8) and specificity of 91.7% (11/12) respectively for detecting significant coronary stenosis.

Application of optical switching technology in a lunar laser ranging system based on a superconducting detector.

The TianQin laser ranging station has successfully obtained the effective echo signals of the all five corner-cube reflectors on the lunar surface by using a 1064 nm Nd:YAG laser with 100 Hz repetition frequency and a 2×2 array of superconducting nanowire single-photon detectors (SNSPDs). The application of the SNSPD in the lunar laser ranging system (LLRS) has demonstrated its detection ability, but it loses its superconducting state and cannot work under strong stray light conditions. In this paper, a high-speed optical switch experimental device based on 100 Hz is developed to solve the application problem of the SNSPD in the LLRS, and its main technical parameters are tested. The results show that the maximum running distance of the switch is 200 µm; the switching time is better than 2 ms; and the extinction ratio is better than 57 dB. Moreover, the application of the high-speed optical switch experimental device in the lunar laser ranging system is designed, and the effective detection time between two laser pulses (10 ms) is determined to be 6.1 ms.