A Real-time SAR Echo Simulator Based on FPGA and Parallel Computing

This paper designs and implements a SAR (Synthetic Aperture Radar) real-time echo simulator based on multi-FPGA parallel computing. The one-dimensional frequency-domain Fourier transform algorithm is used in the simulator, and the echo signal model and the rapid calculation algorithm of impulse response function are introduced. The pipeline compute structure, multichannel parallel computing and procedure flow design are the key technologies of the simulator, which are also presented in details. And finally, the validity and correctness of the SAR echo simulator are verified through the imaging results of the point-array target and the nature scene target

Electrochemical Sensors for Food Safety

Food safety poses an increasing threat to human health worldwide. The development of analytical methods and techniques to ensure food safety is therefore of great importance. Electrochemical sensors provide unique opportunity to realize sensitive, accurate, rapid, and portable detection for food safety. They have the potential to overcome the restrictions and limitations of traditional methods. In this chapter, we review the progress of electrochemical sensors for the detection of food contaminants including heavy metals, illegal additives, pesticide residues, veterinary drug residues, biological toxins, and foodborne pathogen. Future perspectives and challenges are also discussed

"Ribopepzymes" are probably a link from ribozymes to protein enzymes

The evolutionary relationship between RNA- and protein-based biocatalysts was key to the evolution of living systems. This relationship is thought to have depended upon the transfer of both genetic information and catalytic function in living systems. We investigated whether ribozymes could transfer genetic information and catalytic function at the chemical level. We identified a family of peptides encoded by ribozymes: 13-residue peptide encoded by the hammerhead ribozyme, a 19-residue peptide encoded by the genomic hepatitis delta virus (HDV+) ribozyme, a 25-residue peptide encoded by the antigenomic HDV (HDV-) ribozyme, a 15-residue peptide encoded by the smallest trans-acting genomic HDV (SHDV) ribozyme, and a 22-residue peptide encoded by an open reading frame (ORF) of RNase P. We show that all these peptides possess the ability to cleave single-stranded RNA substrates. Furthermore, we expressed a 56-residue peptide encoded by an intact ORF (616-783) of the VS ribozyme, and found that it has single-stranded RNA cleavage activity as well. Because these catalytic peptides arise from a ribozyme-based code and their catalytic activity is ribonuclease-like, we have designated these peptides as "ribopepzymes". Ribopepzymes could be a link from ribozymes to protein enzymes in the early origin and evolution of enzymes. They also may provide a basis for designed, divergent evolution of enzyme function

Effects of Bi³⁺ Doping on the Optical and Electric-Induced Light Scattering Performance of PLZT (8.0/69/31) Transparent Ceramics

Lanthanum modified lead zirconate titanate (abbreviated as PLZT) Electro-Optical ceramics with various Bi concentration were prepared by a hot-press process. The PLZT ceramic samples all present a single perovskite structure with no second phase detected. Bi3+ ion was considered to mainly enter the A-site of perovskite ABO3 structure of PLZT ceramics by the X-Ray Diffractionanalysis. The maximum permittivity (εm) of the PLZT samples decreased obviously as Bi concentration increased, while their remnant polarization (Pr) decreased slightly. In particular, the PLZT sample with 0.14 wt% Bi doping presented a higher optical transmittance 61.8% (λ = 633 nm), and its electric-induced light scattering performance was found to be improved obviously, the maximum light deduction value of ~47.6% was obtained

Side‐effects of carbetocin to prevent postpartum hemorrhage: A systematic review and meta‐analysis of randomized controlled trials

Abstract Postpartum hemorrhage (PPH) increases the risk of maternal death worldwide. Heat‐stable carbetocin, a long‐acting oxytocin analog, is a newer uterotonic agent. Clinicians do not fully understand its side‐effects, particularly the unanticipated side‐effects. The aim of this study is to investigate the side‐effects of carbetocin to PPH. The Cochrane Library, Web of Science, PubMed, Elsevier ScienceDirect, Embase, and ClinicalTrials.gov were searched from the inception to September 2020. Randomized controlled trials (RCTs) that considered pregnant women who received carbetocin before delivery and provided at least one adverse event were included. Statistical analysis included random or fixed‐effect meta‐analyses using relative risk. Stratified analyses and sensitivity analyses were also performed. Begger's and Egger's test and funnel plots were used to assess the publication bias. Seventeen RCTs involving 32,702 women were included, and all these studies ranked as medium‐ to high‐quality. Twenty‐four side‐effects were reported. The use of carbetocin had a lower risk of vomiting in intravenously (0.53, 0.30 to 0.93) and cesarean birth (0.51, 0.32 to 0.81) women, and had a slightly higher risk of diarrhea (8.00, 1.02 to 62.79) compared with oxytocin intervention. No significant difference was found among other side‐effects. Evidence from our systematic review and meta‐analysis of 17 RCTs suggested that the risk of vomiting decreased with carbetocin use in the prevention of PPH after delivery

Morphology, phylogeny, and toxicity of Atama complex (Dinophyceae) from the Chukchi Sea

The "Atama complex", which consists of Alexandrium tamarense, A. fundyense, and A. catenella, is one of the most important groups within the dinoflagellate genus Alexandrium. Information of the biogeography of the Atama complex is limited in the Arctic Ocean. In the present study, we established 55 strains of the Atama complex by incubating ellipsoidal cysts collected from the Chukchi Sea. The vegetative cells are characterized by a prominent ventral pore, thereby fitting the description of A. tamarense morphotype. Large subunit (LSU) and/or internal transcribed spacer (ITS) region sequences of these strains were examined. Both sequences showed intragenomic polymorphism. The 708 bp of the LSU sequences from the strains differed from each other at 0-44 sites (0.0-6.2 %), and the ITS region sequences differed from one another at 0-28 sites (0.0-5.4 %). Phylogenetic analysis revealed that the Chukchi Sea strains were nested within Atama complex (Group I). Assessment of paralytic shellfish poisoning toxin production by four Chukchi Sea strains using high-performance liquid chromatography showed that total toxin per cell ranged from 9 to 41 fmol cell(-1). The toxin profile of the four strains from the Chukchi Sea is conserved, with the major toxins being N-sulfocarbamoyl toxin (C2), saxitoxin, and gonyautoxin-4. Our results support that dispersal of the Atama complex (Group I) from the Bering Sea to the Chukchi Sea might have occurred