Transcriptomic and physiological analysis of the response of Spirodela polyrrhiza to sodium nitroprusside.

BACKGROUND: Spirodela polyrrhiza is a simple floating aquatic plant with great potential in synthetic biology. Sodium nitroprusside (SNP) stimulates plant development and increases the biomass and flavonoid content in some plants. However, the molecular mechanism of SNP action is still unclear. RESULTS: To determine the effect of SNP on growth and metabolic flux in S. polyrrhiza, the plants were treated with different concentrations of SNP. Our results showed an inhibition of growth, an increase in starch, soluble protein, and flavonoid contents, and enhanced antioxidant enzyme activity in plants after 0.025 mM SNP treatment. Differentially expressed transcripts were analysed in S. polyrrhiza after 0.025 mM SNP treatment. A total of 2776 differentially expressed genes (1425 upregulated and 1351 downregulated) were identified. The expression of some genes related to flavonoid biosynthesis and NO biosynthesis was upregulated, while the expression of some photosynthesis-related genes was downregulated. Moreover, SNP stress also significantly influenced the expression of transcription factors (TFs), such as ERF, BHLH, NAC, and WRKY TFs. CONCLUSIONS: Taken together, these findings provide novel insights into the mechanisms of underlying the SNP stress response in S. polyrrhiza and show that the metabolic flux of fixed CO2 is redirected into the starch synthesis and flavonoid biosynthesis pathways after SNP treatment.

A rapid multi-parametric quantitative MR imaging method to assess Parkinson's disease: a feasibility study.

BACKGROUND: MULTIPLEX is a single-scan three-dimensional multi-parametric MRI technique that provides 1 mm isotropic T1-, T2*-, proton density- and susceptibility-weighted images and the corresponding quantitative maps. This study aimed to investigate its feasibility of clinical application in Parkinson's disease (PD). METHODS: 27 PD patients and 23 healthy control (HC) were recruited and underwent a MULTIPLEX scanning. All image reconstruction and processing were automatically performed with in-house C + + programs on the Automatic Differentiation using Expression Template platform. According to the HybraPD atlas consisting of 12 human brain subcortical nuclei, the region-of-interest (ROI) based analysis was conducted to extract quantitative parameters, then identify PD-related abnormalities from the T1, T2* and proton density maps and quantitative susceptibility mapping (QSM), by comparing patients and HCs. RESULTS: The ROI-based analysis revealed significantly decreased mean T1 values in substantia nigra pars compacta and habenular nuclei, mean T2* value in subthalamic nucleus and increased mean QSM value in subthalamic nucleus in PD patients, compared to HCs (all p values < 0.05 after FDR correction). The receiver operating characteristic analysis showed all these four quantitative parameters significantly contributed to PD diagnosis (all p values < 0.01 after FDR correction). Furthermore, the two quantitative parameters in subthalamic nucleus showed hemicerebral differences in regard to the clinically dominant side among PD patients. CONCLUSIONS: MULTIPLEX might be feasible for clinical application to assist in PD diagnosis and provide possible pathological information of PD patients' subcortical nucleus and dopaminergic midbrain regions.

miR-18a-5p shuttled by mesenchymal stem cell-derived extracellular vesicles alleviates early brain injury following subarachnoid hemorrhage through blockade of the ENC1/p62 axis.

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have therapeutic potential in various diseases due to their capacity to transfer bioactive cargoes such as microRNAs (miRNAs or miRs) to recipient cells. The present study isolated EVs from rat MSCs and aimed to delineate their functions and molecular mechanisms in early brain injury following subarachnoid hemorrhage (SAH). We initially determined the expression of miR-18a-5p and ENC1 in hypoxia/reoxygenation (H/R)-induced brain cortical neurons and rat models of SAH induced by the endovascular perforation method. Accordingly, increased ENC1 and decreased miR-18a-5p were detected in H/R-induced brain cortical neurons and SAH rats. After MSC-EVs were co-cultured with cortical neurons, the effects of miR-18a-5p on neuron damage, inflammatory response, endoplasmic reticulum (ER) stress, and oxidative stress markers were evaluated based on ectopic expression and depletion experiments. miR-18a-5p overexpression in brain cortical neurons co-cultured with MSC-EVs was shown to impede neuron apoptosis, ER stress and oxidative stress while augmenting neuron viability. Mechanistically, miR-18a-5p bound to the 3'UTR of ENC1 and reduced its expression, weakening the interaction between ENC1 and p62. Through this mechanism, transfer of miR-18a-5p by MSC-EVs contributed to the eventual inhibition of early brain injury and neurological impairment following SAH. Overall, miR-18a-5p/ENC1/p62 may be a possible mechanism underlying the cerebral protective effects of MSC-EVs against early brain injury following SAH.

Photonic distributed compressive sampling of multi-node wideband sparse radio frequency signals.

A photonic distributed compressive sampling (PDCS) approach for identifying the spectra of multi-node wideband sparse signals is proposed. The scheme utilizes wavelength division multiplexing (WDM) technology to transmit multi-node signals to a central station, where distributed compressive sampling (DCS) based on the random demodulator (RD) model is employed to simultaneously identify the signal spectrum. By exploiting signal correlations among nodes, DCS achieves a higher compression ratio of the sampling rate than single-node compressive sampling (CS). In a semi-physical simulation experiment, we demonstrate the feasibility of the approach by recovering the spectra of two wideband sparse signals from nodes located 20 km and 10 km away. The spectra of two signals with a mixed support-set sparsity of 2 and 4 are recovered with a compression ratio of 8 and 4, respectively. We further investigate the impact of common parts and the number of nodes on PDCS performance through numerical simulation. The proposed system takes advantage of the ultra-high bandwidth of photonic technology and the low loss of optical fiber transmission, making it suitable for long-distance, multi-node, and large-coverage electromagnetic spectrum identification.

Optical pulse interharmonic extraction and repetition rate division based on a microwave photonic phase detector.

Microwave photonic phase detectors (MPPDs) can extract ultrastable microwaves from a mode-locked laser (MLL), but their frequencies are often limited by the pulse repetition rate. Few works studied methods to break the frequency limitation. Here, a setup based on an MPPD and an optical switch is proposed to synchronize an RF signal from a voltage-controlled oscillator (VCO) to an interharmonic of an MLL and to realize the pulse repetition rate division. The optical switch is employed to realize pulse repetition rate division, and the MPPD is followed to detect the phase difference between the frequency-divided optical pulse and the microwave signal from the VCO, which is then fed back to the VCO via a proportional-integral (PI) controller. Both the optical switch and the MPPD are driven by the signal from the VCO. When the system reaches its steady state, the synchronization and repetition rate division are achieved simultaneously. An experiment is conducted to verify the feasibility. The 80½th, 80⅓rd, and 80⅔rd interharmonics are extracted, and pulse repetition rate division factors of two and three are realized. The phase noises at offset frequency of 10 kHz are improved by more than 20 dB.

Anti-Ferroptotic Effects of bone Marrow Mesenchymal Stem Cell-Derived Extracellular Vesicles Loaded with Ferrostatin-1 in Cerebral ischemia-reperfusion Injury Associate with the GPX4/COX-2 Axis.

Accumulating evidence of the critical role of Ferrostatin-1 (Fer-1, ferroptosis inhibitor) in cerebral ischemia has intrigued us to explore the molecular mechanistic actions of Fer-1 delivery by bone marrow mesenchymal stem cells-derived extracellular vesicles (MSCs-EVs) in cerebral ischemia-reperfusion (I/R) injury. In vivo middle cerebral artery occlusion (MCAO) in mice and in vitro oxygen-glucose deprivation/reperfusion (OGD/R) in hippocampal neurons were developed to simulate cerebral I/R injury. After Fer-1 was confirmed to be successfully delivered by MSCs-EVs to neurons, we found that MSCs-EVs loaded with Fer-1 (MSCs-EVs/Fer-1) reduced neuron apoptosis and enhanced viability, along with curtailed inflammation and ferroptosis. The regulation of Fer-1 on GPX4/COX2 axis was predicted by bioinformatics study and validated by functional experiments. The in vivo experiments further confirmed that MSCs-EVs/Fer-1 ameliorated cerebral I/R injury in mice. Furthermore, poor expression of GPX4 and high expression of COX-2 were witnessed in cerebral I/R injury models. MSCs-EVs/Fer-1 exerted its protective effects against cerebral I/R injury by upregulating GPX4 expression and inhibiting COX-2 expression. Taken together, our study indicates that MSCs-EVs/Fer-1 may be an attractive therapeutic target for the treatment of cerebral I/R injury due to its anti-ferroptotic properties.

Integrative phosphatidylcholine metabolism through phospholipase A2 in rats with chronic kidney disease.

Dysregulation in lipid metabolism is the leading cause of chronic kidney disease (CKD) and also the important risk factors for high morbidity and mortality. Although lipid abnormalities were identified in CKD, integral metabolic pathways for specific individual lipid species remain to be clarified. We conducted ultra-high-performance liquid chromatography-high-definition mass spectrometry-based lipidomics and identified plasma lipid species and therapeutic effects of Rheum officinale in CKD rats. Adenine-induced CKD rats were administered Rheum officinale. Urine, blood and kidney tissues were collected for analyses. We showed that exogenous adenine consumption led to declining kidney function in rats. Compared with control rats, a panel of differential plasma lipid species in CKD rats was identified in both positive and negative ion modes. Among the 50 lipid species, phosphatidylcholine (PC), lysophosphatidylcholine (LysoPC) and lysophosphatidic acid (LysoPA) accounted for the largest number of identified metabolites. We revealed that six PCs had integral metabolic pathways, in which PC was hydrolysed into LysoPC, and then converted to LysoPA, which was associated with increased cytosolic phospholipase A2 protein expression in CKD rats. The lower levels of six PCs and their corresponding metabolites could discriminate CKD rats from control rats. Receiver operating characteristic curves showed that each individual lipid species had high values of area under curve, sensitivity and specificity. Administration of Rheum officinale significantly improved impaired kidney function and aberrant PC metabolism in CKD rats. Taken together, this study demonstrates that CKD leads to PC metabolism disorders and that the dysregulation of PC metabolism is involved in CKD pathology.

C, F co-doping Ag/TiO2 with visible light photocatalytic performance toward degrading Rhodamine B.

The organic pollutants in industrial wastewater continuously endanger human health. Therefore, effective treatment of organic pollutants is very urgent. Photocatalytic degradation technology is an excellent solution to remove it. TiO2 photocatalysts are easy to prepare and have high catalytic activity, unfortunately, TiO2 only absorbs ultraviolet light limiting its utilization of visible light. In this study, a facile environmentally friendly synthesis of Ag-coated on micro-wrinkled TiO2-based catalysts in order to extend the absorption of Visible light. Firstly, a fluorinated titanium dioxide precursor was prepared by a one-step solvothermal method, and the precursor was calcined at high temperature in a nitrogen atmosphere to form a carbon dopant, and then a surface silver-deposited carbon/fluorine co-doped TiO2 photocatalyst C/F-Ag-TiO2 was prepared by a hydrothermal method The results showed that the Ag was coated on the wrinkled TiO2 layer and C/F-Ag-TiO2 photocatalyst was synthetized successfully. Benefit from the synergistic effect of doped carbon and fluorine atoms in combination with the quantum size effect of the surface silver nanoparticles, the band gap energy of C/F-Ag-TiO2 (2.56 eV) is obviously lower than anatase (3.2eV). The photocatalyst achieved an impressive degradation rate of 84.2% for Rhodamine B in 4 h, with a degradation rate constant of 0.367 h-1, which was 17 times higher than that of P25 under visible light. Therefore, the C/F-Ag-TiO2 composite is a promising candidate as a highly efficient photocatalyst for environmental remediation.

Evaluation and validation of the prognostic value of anti-MDA5 IgG subclasses in dermatomyositis-associated interstitial lung disease.

OBJECTIVE: To investigate the association between the anti-melanoma differentiation associated gene 5 (MDA5) IgG subclasses and prognosis of patients with dermatomyositis (DM)-associated interstitial lung disease (ILD). METHODS: This retrospective study included 122 anti-MDA5 positive DM-ILD patients admitted from October 2017 to October 2020 as training cohort, and additional 68 patients from August 2014 to September 2017 as validation cohort. The levels of anti-MDA5 total IgG and IgG subclasses were measured using in-house enzyme-linked immunosorbent assays, and analysed in association with the patient prognosis. RESULTS: In the training cohort, the concentrations of anti-MDA5 IgG1 and IgG3 in non-survivors were significantly higher than in survivors (P < 0.05), whereas there were no significant differences in the IgG2 and IgG4 levels. Kaplan-Meier survival analysis revealed that the levels of anti-MDA5 total IgG, IgG1 and IgG3 were associated with mortality (P < 0.05). Multivariate analysis revealed anti-MDA5 IgG1 >13 U/ml and anti-MDA5 IgG3 >11 U/ml were independent risk factors for death of DM-ILD patients (P < 0.05). Anti-MDA5 IgG1 was confirmed as an independent risk factor in the validation cohort, while anti-MDA5 IgG3 was not. Anti-MDA5 IgG1 showed greater discriminable power for patient prognosis (Youden index 0.494) than anti-MDA5 total IgG, IgG3, or the combination of IgG1 and IgG3 (Youden index 0.356, 0.32 and 0.447, respectively). CONCLUSION: Anti-MDA5 IgG1 and IgG3 are significantly associated with poor prognosis in DM-ILD patients, and anti-MDA5 IgG1 is more efficient as a prognostic biomarker in DM-ILD patients.

Terahertz liquid crystal programmable metasurface based on resonance switching.

A programmable metasurface based on liquid crystal is of great significance to versatile dynamic wave manipulation such as beamforming and beam steering. One of the biggest obstacles currently is the lack of a simple way to multi-bit programming scheme for massive electrically addressable arrays, which limits its application and magnifies drawbacks like unavoidable symmetrical beam diffraction. Here, we put forward the concept of a liquid crystal metasurface based on a resonance switching mechanism for quasi-2-bit coding control, which is established upon interdigital structure electrodes. This enables a more elaborate control of meta-unit and a quasi-2-bit modulation based on a universal binary coding system to be realized. Our design could suppress unwanted -1 diffraction order with a maximum single-beam scanning angle of ± 21° under active beam manipulation. This concept paves the way for a feasible and robust multi-bit coding scheme of a liquid crystal metasurface, which is promising for THz applications such as spatial light modulators and wireless communication.

Young Children Allergic Rhinitis Questionnaire is a novel tool for allergy screening in children.

BACKGROUND: There are a limited number of validated questionnaires available for use in the clinical screening for allergic rhinitis (AR) in children ≤3 years old. We developed a novel self-reported questionnaire and assessed its accuracy and reliability. METHODS: After establishing a pool of items, which were screened by experts, the Young Children Allergic Rhinitis Questionnaire (YCAR-Q) was administered to a birth cohort in the Shunyi District (Beijing, China). The electronic version of the YCAR-Q was distributed through the online community. Children were invited to visit a physician for examination. The diagnostic criteria included symptoms, physical examination findings, and specific serum immunoglobulin E tests. Each item on the questionnaire was evaluated, and the questionnaire's internal consistency, content validity, criterion-related validity, and diagnostic accuracy were assessed. RESULTS: The six-item YCAR-Q was distributed to 7423 parents, and 3037 valid questionnaires were recovered. In total, 1521 children visited a physician for examination, of which 82 were found to have AR. In terms of internal consistency, Cronbach's coefficient was 0.777 and all six questionnaire items were retained. The average scale-level content validity index value was 1. The area under the curve was 0.759. The total scores ranged from 0 to 6, and the cutoff value for diagnosing AR was 3, with a sensitivity of 68.29% and a specificity of 76.58%. CONCLUSIONS: This cross-sectional study indicated that the YCAR-Q could detect AR in children ≤3 years old. This brief and simple test may be used effectively in clinical practice.

Association between Cardiac Outcomes and Indoxyl Sulfate Levels in Hemodialysis Patients: A Cross-Sectional Study.

OBJECTIVE: Indoxyl sulfate (IS) is a protein-bound uremic toxin that is associated with cardiovascular events and mortality in hemodialysis (HD) patients. However, the factors affecting the levels of IS are currently unclear. This study aimed to investigate the factors influencing serum IS concentrations in HD patients. METHODS: We included 100 HD patients from Guangdong Provincial People's Hospital. Baseline characteristics, including sex, age, clinical features, duration of HD, echocardiography findings, electrocardiogram results, and biochemical indicators, were collected and analyzed in relation to serum total-form IS levels. RESULTS: Among all 100 patients, serum IS levels were significantly higher in patients aged ≥60 years, males, and patients with mitral regurgitation and inadequate dialysis. Among patients aged <60 years, IS levels were significantly higher among patients with mitral regurgitation compared with those without. Furthermore, multiple linear regression analysis identified sex, age, ventricular septal thickness, and mitral regurgitation as factors independently associated with serum IS (STDß = -0.475, 0.162, -0.153, 0.142, and 0.136, respectively; all p < 0.05) adjusted for body mass index, smoking, and fasting plasma glucose. CONCLUSIONS: Male sex, age ≥60 years, ventricular septal thickness, and mitral regurgitation are factors associated with high total serum IS concentrations in Chinese HD patients. Elevated IS levels may play a role in the process of mitral regurgitation in HD patients <60 years of age.

Three new cassane-type diterpenoids from Caesalpinia sinensis.

Three new cassane-type diterpenoids, namely, (4S)-6ß,12α,19-trihydroxy-cass-13(15)-en-16,12-olide (1), cass-13(15)-en-​16,12-olide (2), and 12α-hydroxy-cass-13(15)-en-16,12-olide (3), were isolated from the seeds of Caesalpinia sinensis. The structures of 1-3 were established by extensive spectroscopic analysis, and their absolute configurations were assigned by electronic circular dichroism (ECD) calculations. The inhibitory activities against PTP1B of the isolated compounds were evaluated. The results showed that compound 2 possessed PTP1B inhibitory activity with an IC50 value of 217.45 ± 36.4 µM.

Schisandrin B ameliorates non-alcoholic liver disease through anti-inflammation activation in diabetic mice.

Type 2 diabetes mellitus (T2DM) is a metabolic risk factor associated with non-alcoholic liver disease (NAFLD). Schisandrin B (Sch B) is a promising agent for NAFLD. However, the actions of Sch B on diabetes-associated NAFLD and the underlying mechanisms are not characterized. This study aimed to assess whether Sch B has beneficial effects on T2DM-associated NAFLD. Sch B (50 mg/kg, gavage) was administrated to C57BL/KSJ db/db mice for 2 weeks. Body weight, liver weight, blood glucose, and insulin resistance were measured. Serum lipid level and liver function were detected using the biochemistry analyzer. Quantitative Real-Time PCR assay was used to evaluate mRNA levers of lipid metabolism genes. Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling (TUNEL) staining was performed to measure apoptosis in the liver. Pathological analysis and immunohistochemistry assessment were used to analyze hepatic steatosis and inflammatory infiltration. Sch B supplementation significantly decrease body weight, related liver weight, blood glucose, and serum insulin, and improved insulin resistance in db/db mice. Sch B obviously corrected NAFLD phenotypes including lipid deposition, steatohepatitis, and high levels of hepatic enzymes and serum lipid. In addition, mRNA levels of Sterol response element-bind protein 1c (SREBP-1c), fatty acid synthetase (Fasn), and acetyl-CoA carboxylase (ACC) were markedly downregulated by Sch B treatment. TUNEL-positive cells were also decreased by Sch B. Furthermore, Sch B inhibited the Kupffer cells, IL-1ß, and TNF-α infiltration to the liver. Sch B ameliorated insulin resistance and lipid accumulation under high glucose conditions, which was partly associated with its inhibition of apoptosis and anti-inflammatory actions.

A population-based analysis of clinical features and lymph node dissection in head and neck malignant neurogenic tumors.

BACKGROUND: The influence of lymph node dissection (LND) on survival in patients with head and neck neurogenic tumors remains unclear. We aimed to determine the effect of LND on the outcomes of patients with head and neck neurogenic tumors. METHODS: Data of patients with surgically treated head and neck neurogenic tumors were identified from the Surveillance, Epidemiology, and End Results (SEER) database (1975-2016) to investigate the relationship between LND and clinical outcomes by survival analysis. Subgroup analysis was performed in IVa and IVb group. RESULTS: In total, 662 head and neck neurogenic tumor patients (median age: 49.0 [0-91.0] years) met the inclusion criteria, of whom 13.1% were in the IVa group and 86.9% were in the IVb group. The median follow-up time was 76.0 months (range: 6.0-336.0 months), and the 5-year and 10-year overall survival was 82.4% (95% CI, 0.79-0.85) and 69.0% (95% CI, 0.64-0.73). Cox regression analysis revealed older age (P < .001), advanced stage (P = .037), African American race (P = .002), diagnosis before 2004 (P < .001), and chemotherapy administration (P < .001) to be independent negative predictors of overall survival. Kaplan-Meier analysis demonstrated that LND was not a predictor of clinical nodal negativity (cN0) in either IVa or IVb patients. CONCLUSIONS: In head and neck neurogenic patients, LND may not impact the outcome of cN0 in either IVa or IVb group. These data can be recommended in guiding surgical plan and future studies.

Intranasal fluticasone furoate in pediatric allergic rhinitis: randomized controlled study.

BACKGROUND: Intranasal corticosteroids are the most efficacious anti-inflammatory medications for allergic rhinitis (AR). However, the efficacy and safety of intranasal corticosteroids in children have not yet been subject to specific research in China. The aim of this study was to investigate the efficacy and safety of fluticasone furoate nasal spray (FFNS) in a Chinese pediatric population. METHODS: In this phase 4 randomized, double-blind, placebo-controlled, multicenter study, pediatric AR patients aged 2-12 years were randomized 1:1:1, receiving either FFNS 55 µg or 110 µg or placebo. Electronic diary cards were completed to record symptoms, rescue medication use, and treatment compliance. Anterior rhinoscopy and overall response to therapy were evaluated and recorded. RESULTS: Patients treated with FFNS at either dose experienced a significantly greater reduction in daily reflective total nasal symptom score compared with placebo. This was maintained in a younger subset of patients (2-6 years). Drug-related adverse events occurred in <20% of patients in all groups. FFNS was well tolerated at both doses. CONCLUSIONS: This study demonstrates favorable efficacy and safety profiles for FFNS 55 µg or 110 µg in Chinese pediatric populations (2-12 years), supporting its use in clinical treatment for AR children, including younger children aged 2-6 years. IMPACT: The aim of this study was to investigate the efficacy and safety of intranasal fluticasone furoate in Chinese pediatric allergic rhinitis. This research not only addresses the deficiency in efficacy and safety data for intranasal corticosteroids in very young patients (aged 2-6 years) worldwide but also demonstrates that fluticasone furoate nasal spray shows a favorable benefit/risk profile at different dose levels. Our data will be of interest to the broad readership of Pediatric Research and will positively contribute to the dialog regarding the treatment of allergic rhinitis in children aged 2-6 years.

Demographic Characteristics and Lifestyle Habits of Chinese Plasma Donors: A Multicenter Study.

BACKGROUND The demand for plasma and plasma products has increased in China, which has a short supply. Compared with whole blood donors, plasma donors and their donation behavior have received less attention. This study aimed to investigate the demographic characteristics and lifestyle habits of Chinese plasma donors. MATERIAL AND METHODS During 2018-2019, information on plasma donors was collected from blood product companies using a 25-item questionnaire, including sex, age, height, weight, blood group, donation frequency, occupation, smoking and drinking, and sleeping and dietary habits. RESULTS Among 15 497 plasma donors, 70.5% were women and 78.5% were aged 46-55 years. Among 4847 plasma donors, the average height of men was 169.5±6.2 cm and the average height of women was 157.0±4.6 cm. In addition, the average weight of men was 67.0±10.4 kg and the average weight of women was 60.0±8.3 kg. The prevalence of obesity (body mass index ≥30.0 kg/m²) of all donors was 14.8%; 14.7% of men were obese, and 15% of women were obese. Among all plasma donors, 88.8% were farmers and 60% were frequent donors with a donation history of at least 5 years. Among all donors, 84.0% did not smoke, 67.3% did not drink, and 95.1% reported good sleep quality. All respondents reported healthy dietary habits. CONCLUSIONS Healthy lifestyle habits considerably affect the health of plasma donors and the quality of source plasma. Chinese plasma donors in this study demonstrated imbalances in terms of characteristics, which became more marked with age.

Single-Molecule Imaging in Living Plant Cells: A Methodological Review.

Single-molecule imaging is emerging as a revolutionary approach to studying fundamental questions in plants. However, compared with its use in animals, the application of single-molecule imaging in plants is still underexplored. Here, we review the applications, advantages, and challenges of single-molecule fluorescence imaging in plant systems from the perspective of methodology. Firstly, we provide a general overview of single-molecule imaging methods and their principles. Next, we summarize the unprecedented quantitative details that can be obtained using single-molecule techniques compared to bulk assays. Finally, we discuss the main problems encountered at this stage and provide possible solutions.

Accelerated convergence extended ptychographical iterative engine using multiple axial intensity constraints.

The extended ptychographical iterative engine (ePIE) is widely applied in the field of ptychographic imaging due to its great flexibility and computational efficiency. A technique of ePIE with multiple axial intensity constraints, which is called MAIC-PIE, is proposed to drastically improve the convergence speed and reduce the calculation time. This technique requires that the diffracted light from the sample is propagated to the multiple individual axial planes, which can be achieved by using the beam splitter and multiple CCDs. In this technique, an additional intensity constraint is involved in the iterative process that makes for building the reasonable guesses of the probe and object in the first few iterations and accelerating the convergence. Simulations and experiments have verified that MAIC-PIE behaves good performance with fast convergence. The great performance and limited computational complexity make it a very attractive and promising technique for ptychographic imaging.

Multioctave and reconfigurable frequency-stepped radar waveform generation based on an optical frequency shifting loop.

A photonic method for multioctave and reconfigurable frequency-stepped radar waveform generation is proposed and experimentally demonstrated based on an optical frequency shifting loop (OFSL). When a rectangular optical pulse is applied to the OFSL, a frequency-stepped optical signal can be generated. Beating the signal with another continuous-wave optical carrier, an electrical frequency-stepped waveform can be obtained. By meticulously adjusting the relations between the time duration of the rectangular optical pulse and the loop delay of the OFSL, the frequency-hopping rate (or the frequency-hopping period) of the generated frequency-stepped signal can be reconfigured. An experiment is carried out. The generation of frequency-stepped signals with frequency intervals of 1 GHz, 3 GHz, 5 GHz, 8 GHz, and 10 GHz is realized. The reconfigurability of the frequency-hopping period is also investigated and different frequency-hopping periods of 189, 10.2, 5.1, and 2.42 ns are achieved.