Coherent stepped-frequency waveform generation based on recirculating microwave photonic frequency conversion.

We propose a novel method for generating coherent and wideband stepped-frequency waveforms using recirculating microwave photonic frequency conversion (MWP-FC). By injecting a narrowband signal into an MWP-FC loop utilizing a dual-parallel Mach-Zehnder modulator (DPMZM), the signal frequency is continuously converted to produce a stepped-frequency waveform with a wide bandwidth. Within the MWP-FC loop, photo-electric conversion is achieved based on self-mixing detection, where the optical phase noise can be suppressed, guaranteeing stability and coherence of the generated signal. In a proof-of-concept experiment, a stepped-frequency signal with a frequency interval of 2 GHz and a bandwidth of about 16 GHz and a stepped-frequency chirp signal with a frequency interval of 3 GHz and a bandwidth of about 15 GHz are generated. In addition, coherence of the generated signals is verified by coherent integration and de-chirping.

The centralspindlin complex regulates cytokinesis and morphogenesis in the C. elegans spermatheca.

Organ morphogenesis needs orchestration of a series of cellular events, including cell division, cell shape change, cell rearrangement and cell death. Cytokinesis, the final step of cell division, is involved in the control of organ size, shape and function. Mechanistically, it is unclear how the molecules involved in cytokinesis regulate organ size and shape. Here, we demonstrate that the centralspindlin complex coordinates cell division and epithelial morphogenesis by regulating cytokinesis. Loss of the centralspindlin components CYK-4 and ZEN-4 disrupts cell division, resulting in altered cell arrangement and malformation of the Caenorhabditis elegans spermatheca. Further investigation revealed that most spermathecal cells undergo nuclear division without completion of cytokinesis. Germline mutant-based analyses suggest that CYK-4 regulates cytokinesis of spermathecal cells in a GTPase activator activity-independent manner. Spermathecal morphology defects can be enhanced by double knockdown of rho-1 and cyk-4, and partially suppressed by double knockdown of cdc-42 and cyk-4. Thus, the centralspindlin components CYK-4 and ZEN-4, together with RHO-1 and CDC-42, are central players of a signaling network that guides spermathecal morphogenesis by enabling completion of cytokinesis.

From primordial germ cells to spermatids in Caenorhabditis elegans.

Development of a syncytial germline for gamete formation requires complex regulation of cytokinesis and cytoplasmic remodeling. Recently, several uncovered cellular events have been investigated in the Caenorhabditis elegans (C. elegans) germline. In these cellular processes, the factors involved in contractility are highly conserved with those of mitosis and meiosis. However, the underlying regulatory mechanisms are far more complicated than previously thought, likely due to the single syncytial germline structure. In this review, we highlight how the proteins involved in contractility ensure faithful cell division in different cellular contexts and how they contribute to maintaining intercellular bridge stability. In addition, we discuss the current understanding of the cellular events of cytokinesis and cytoplasmic remodeling during the development of the C. elegans germline, including progenitor germ cells, germ cells, and spermatocytes. Comparisons are made with relevant systems in Drosophila melanogaster (D. melanogaster) and other animal models.

The Enhancement of Antiviral Activity of Chloroinconazide by Aglinate-based Nanogel and Its Plant Growth Promotion Effect.

Improving the efficiency and prolonging the duration of pesticides are of great significance in agricultural production. In this work, based on the antiviral compound chloroinconazide (CHI) synthesized previously, the improvement of the fabricated CHI-loaded alginate-based nanogel (CHI@ALGNP) was studied. It was found that CHI@ALGNP showed higher foliar adhesion than CHI and exhibited a sustained release for up to 7 days. CHI@ALGNP could also continuously activate the reactive oxygen species and antioxidant levels and induce the increase of salicylic acid content and the expression of its responsive gene PR2 for a long time, thus achieving sustained resistance to tobacco mosaic virus infection in Nicotiana benthamiana. Strikingly, CHI@ALGNP could release Ca2+ and Mg2+ to promote the growth of N. benthamiana. Taken together, for the first time, we have shown the improvement of a nanogel carrier to the antiviral activity and growth promotion of small molecular pesticides. As the alginate-based nanogel can be easily applied to the spray-based pesticide delivery technology, our study provides a new strategy for the development of new pesticide preparations and the application of multifunctional pesticides.

Cortical recruitment of centralspindlin and RhoA effectors during meiosis I of Caenorhabditiselegans primary spermatocytes.

Haploid male gametes are produced through meiosis during gametogenesis. Whereas the cell biology of mitosis and meiosis is well studied in the nematode Caenorhabditis elegans, comparatively little is known regarding the physical division of primary spermatocytes during meiosis I. Here, we investigated this process using high-resolution time-lapse confocal microscopy and examined the spatiotemporal regulation of contractile ring assembly in C. elegans primary spermatocytes. We found that centralspindlin and RhoA effectors were recruited to the equatorial cortex of dividing primary spermatocytes for contractile ring assembly before segregation of homologous chromosomes. We also observed that perturbations shown to promote centralspindlin oligomerization regulated the cortical recruitment of NMY-2 and impacted the order in which primary spermatocytes along the proximal-distal axis of the gonad enter meiosis I. These results expand our understanding of the cellular division of primary spermatocytes into secondary spermatocytes during meiosis I.This article has an associated First Person interview with the first author of the paper.

Epidemiological investigation for chronic kidney disease in freshmen from a university in Hunan Province. / æ¹–å—çœæŸé«˜æ ¡æ–°ç”Ÿæ ¢æ€§è‚¾è„ç— æµè¡Œç— å­¦è°ƒæŸ¥.

OBJECTIVES: To understand the prevalence and risk factors for chronic kidney disease (CKD) among freshmen from a university in Hunan Province in 2018. METHODS: A cross-sectional survey was conducted on 1 685 freshmen from a university in Hunan Province in 2018. Height, weight, body mass index (BMI), blood pressure, creatinine, uric acid, fasting blood glucose, triglyceride, total cholesterol, blood urea nitrogen, and other laboratory indicators were measured. The risk factors of hematuria, proteinuria, and CKD were analyzed by logistic regression. RESULTS: Among the 1 685 students, the detection rates of proteinuria, hematuria, and renal dysfunction were 2.14%, 6.65%, and 0.95%, respectively. The prevalence of CKD was 10.86%, mainly at stage 1 and 2. The awareness rate in the patients was 6.56%. The detection rate of proteinuria was not significantly correlated with gender, and the detection rate of hematuria and renal dysfunction was higher in women than in men, and the prevalence of CKD was higher in women than in men. Independent risk factors associated with CKD were hypertension and diabetes. CONCLUSIONS: In 2018, the prevalence of CKD among freshmen in this university is roughly the same as the national level. CKD patients and people with hypertension and diabetes should be checked regularly, and early intervention should be performed to delay the occurrence and development of the disease.

A Deep-Red to Near Infrared (NIR) Fluorescent Probe Based on a Sulfur-Modified Rhodamine Derivative with Two Spirolactone Rings.

We report the synthesis, characterization, and photophysical and ion-binding properties of deep-red to near-infrared (NIR) fluorescent rhodamine derivatives, bearing two spirolactone rings and substitution of the oxygen atoms in the xanthene ring with sulfur atoms (1-S). The diastereoisomeric cis- and trans-forms of the rhodamine derivative were separated and the cis-form (cis-1-S) was structurally characterized by X-ray crystallography. Upon treatment with Hg2+ ion, cis-1-S was converted into the dual spirolactone ring-opened species, resulting in significant color change and fluorescence enhancement. Substitution of the oxygen atoms with sulfur and extended π-conjugation across the fused six-membered rings upon the two rings-opening processes in the presence of Hg2+ ion led to a significant red-shift of absorption (623 nm) and fluorescence (706 nm) peaks, compared to the ordinary rhodamine. Furthermore, the intracellular Hg2+ -sensing properties of the cis-1-S have been studied by confocal microscopy.

Synthetic chloroinconazide compound exhibits highly efficient antiviral activity against tobacco mosaic virus.

BACKGROUND: Development of anti-plant-virus compounds and improvement of biosafety remain hot research topics in controlling plant viral disease. Tobacco mosaic virus (TMV) infects all tobacco species as well as many other plants worldwide and causes severe losses in tobacco production. To date, no efficient chemical treatments are known to protect plants from virus infection. Therefore, the search for a highly active antiviral compound with high efficacy in field application is required. RESULTS: We reported the synthesis of a novel antiviral halogenated acyl compound Chloroinconazide (CHI) using tryptophan as a substrate and examined its anti-TMV activity. We found that CHI displayed the ability to strongly inhibit the infection of TMV on Nicotiana benthamiana via multiple mechanisms. We observed that CHI was able to impair the virulence of TMV by directly altering the morphological structure of virions and increasing the activity of anti-oxidative enzymes, resulting in reduced TMV-induced ROS production during infection of the plant. In addition, the expression of salicylic acid-responsive genes was significantly increased after CHI application. However, after application of CHI on SA-deficient NahG plants no obvious anti-TMV activity was observed, suggesting that the SA signaling pathway was required for CHI-induced anti-TMV activity associated with reduced infection of TMV. CHI exhibited no effects on plant growth and development. CONCLUSION: The easily synthesized CHI can actively induce plant resistance against TMV as well as act on virus particles and exhibits high biosafety, which provides a potential for commercial application of CHI in controlling plant virus disease in the future. © 2020 Society of Chemical Industry.

[An epidemiological investigation of chronic kidney disease in children with hearing disorder in Hunan province, China].

OBJECTIVE: To investigate the prevalence of chronic kidney disease (CKD) among the children with hearing disorder in Hunan province, China. METHODS: In this cross-sectional study, the multi-stage cluster sampling method was used to select 1 500 children as subjects. Questionnaire surveys, physical examinations, and laboratory examinations were performed on the spot. RESULTS: Among the 1 500 children, 1 459 with complete data were included in analysis. Among the 1 459 children, 43 had CKD, with a prevalence rate of 2.95%. The <7 years group had a significantly higher prevalence rate than the 7-14 years group [5.8% (35/604) vs 0.9% (8/855); P<0.05]. Among the 43 children with CKD, 31 (72%) had proteinuria, 27 (63%) had hematuria, and 11 (26%) had a decreased glomerular filtration rate. Among the 43 children with CKD, stage 1, 2, 3a, 3b, 4, and 5 CKD accounted for 30% (13 cases), 44% (19 cases), 12% (5 cases), 7% (3 cases), 7% (3 cases), and 0% (0 case) respectively. The prevalence rate of CKD increased with the severity of hearing disorder (P<0.01). CONCLUSIONS: The prevalence rate of CKD is higher among the children with hearing disorder in Hunan province. Most children have early-stage CKD. CKD is commonly seen in preschool children. Severity of hearing disorder is associated with the prevalence of CKD.

Multi-vibration detection by probe pulses with ergodic SOPs in a POTDR system.

Polarization optical time domain reflectometers (POTDR) can detect vibration of fiber via the change of the state of polarization (SOP) of the Rayleigh backscattered light. For traditional POTDR systems, one key problem is the high misdiagnosis rate when multiple vibrations are simultaneously applied on the sensing fiber due to the random birefringence along the fiber. To solve this problem, we propose in this paper a novel implementation of the POTDR using probe pulses with ergodic SOPs. A series of vibration spectra along the fiber are obtained by sweeping the SOP of the probe pulse. The sum of these vibration spectra, which should be immune to the birefringence of the sensing fiber, is used to analyze the vibration information. Numerical simulation and experiments are carried out to analyze the performance of the proposed system when the input SOPs are traversed with uniform distribution and random distribution. Results show that the misdiagnosis rate of detecting multi-vibration with different frequencies is greatly reduced. In addition, detection of more-than-two vibrations with the same frequency based on POTDR is successfully performed for the first time to the best of our knowledge.

Clinical and pathological analysis of the kidney in patients with hypertensive nephropathy.

The aim of the present study was to identify the association between pathological types of kidney and clinical manifestations in patients with hypertensive nephropathy. The blood pressure, fundus, urinalysis test results and renal function changes were analysed in patients who were treated for hypertensive nephropathy. Downward kidney puncture biopsy was performed using a 16G ejection needle with the aid of B ultrasound in 47 cases. The specimens were observed using light microscopy and immunofluorescence. The pathological changes observed in the patients exhibiting symptoms of hypertensive nephropathy varied. The majority of clinical manifestations were benign arteriolar nephrosclerosis, hyaline degeneration of the renal artery and the appearance of a thickened wall of a thickened renal artery wall. Severe cases showed malignant arteriolar nephrosclerosis characterised by fibrinoid necrosis of renal arterioles and intimal hyperplasia. In addition, in the severe cases, fibrinoid necrosis of the afferent arteriole and arcuate artery wall was observed, with severe interlobular artery and arcuate artery myointimal thickening. Renal biopsy in patients with hypertensive nephropathy is safe and feasible. The prognosis and treatment of pathological and clinical disease related to renal pathology is necessary.

Distributed fiber strain and vibration sensor based on Brillouin optical time-domain reflectometry and polarization optical time-domain reflectometry.

A distributed fiber strain and vibration sensor which effectively combines Brillouin optical time-domain reflectometry and polarization optical time-domain reflectometry is proposed. Two reference beams with orthogonal polarization states are, respectively, used to perform the measurement. By using the signal obtained from either reference beam, the vibration of fiber can be measured from the polarization effect. After combining the signals obtained by both reference beams, the strain can be measured from the Brillouin effect. In the experiment, 10 m spatial resolution, 0.6 kHz frequency measurement range, 2.5 Hz frequency resolution, and 0.2 MHz uncertainty of Brillouin frequency measurement are realized for a 4 km sensing distance.

Influence of optical pulse width on the perturbation detection performance of polarization-optical time domain reflectometer.

The influence to the sensing performance of polarization optical time domain reflectometer (POTDR) by increasing the optical pulse width is analyzed based on wave-plate model and Muller matrices. Simulation and experimental results show that the ability of POTDR to sense external perturbation can be improved by increasing the pulse width of probe light, although the backscattered signal would be temporally depolarized. The depolarization effect is not a limitation to increase the pulse width to improve the signal-to-noise ratio for POTDR. The beat length of fiber can be taken as the critical value for the increase of pulse width.

Synthesis of tetrasubstituted cyclopentadienes via palladium-catalyzed reaction of (Z)-2-en-4-yn acetates and N-methyl indoles.

An efficient approach for the synthesis of tetrasubstituted cyclopentadienes through Pd-catalyzed reactions of (Z)-2-en-4-yn acetates with substituted indoles was developed. This methodology has the advantages of broad scope, simple conditions and easily accessible starting materials.

One pot synthesis of indene through copper(I)-catalyzed three-components coupling and cyclization reaction.

A new and efficient synthesis of substituted indene has been achieved via copper(I)-catalyzed domino three-component coupling and cyclization reaction in moderate to good yield.

Bi(III)-catalyzed intermolecular reactions of (Z)-pent-2-en-4-yl acetates with ethynylarenes for the construction of multisubstituted fluorene skeletons through a cascade electrophilic addition/cycloisomerization sequence.

A Bi(III)-catalyzed method for the synthesis of highly conjugated aromatic multisubstituted fluorene with (Z)-pent-2-en-4-yl acetates and ethynylarenes via domino reaction is described. In this process, the reaction appears to be very general and suitable for a variety of multisubstituted fluorene.

Copper-catalyzed dimerization fragmentation cyclization reactions of (E)-1-en-4-yn-3-ols as a versatile approach for the synthesis of multisubstituted 1H-cyclopenta[b]naphthalenes.

An intermolecular condensation reaction of 1,3,5-triarylenynols catalyzed by copper is developed. This reaction is a straightforward method for the synthesis of highly conjugated 1H-cyclopenta[b]naphthalene. Fluorescent properties have been determined for some of the products.

Palladium-catalyzed aryl C-H bonds activation/acetoxylation utilizing a bidentate system.

A palladium-catalyzed aryl C-H bonds activation/acetoxylation reaction utilizing a bidentate system has been explored. This transformation has been applied to a wide array of pyridine and 8-aminoquinoline derivatives and it exhibits excellent functional group tolerance.