Abstract: The present invention relates to optimized nucleotide sequence encoding SARS-COV-2 antigens. These sequences are particularly suitable for use in vaccine compositions for the treatment or prevention of infections caused by a ?-coronaviruses, including COVID-19 infections, in a human or animal subject in need of such treatment.

Abstract: The invention relates to a method of quantifying capping efficiency in a sample from an in vitro transcription reaction mixture comprising a plurality of mRNA transcript, characterized by a step of contacting the mRNA transcripts with an oligonucleotide complementary to a sequence of nucleotides in the 5? untranslated region of the mRNA transcripts to form an mRNA:DNA hybrid between the oligonucleotide and the sequence of nucleotides of the mRNA transcripts in order to release the first five, six, or seven nucleotides of the mRNA transcripts using nuclease (e.g., RNAse H) digestion.

Abstract: The present invention provides methods for preparing optimized DNA sequences as templates for in vitro transcription of mRNA. These DNA sequences are optimized to avoid premature termination of transcription by RNA polymerase. The invention also provides methods for preparing optimized DNA sequences that include one or more termination signal at their 3? end to reduce or prevent non-templated “runoff” transcription.

Abstract: The present disclosure discloses a Beidou signal tracking system with a nonlinear phase-locked loop. A nonlinear element and a low-pass filter are added behind a loop filter to adapt to an output from control of the loop filter, and then to control a phase of an output signal. An in-phase branch pre-filtering link is added before the loop filter to smoothly processing an input signal, and a loop filter of a third-order phase-locked loop assisted by a second-order frequency-locked loop is selected to ensure basic performance index of an algorithm. The in-phase branch pre-filtering link controls signal change of an in-phase branch signal within a reasonable range. The nonlinear element and the low-pass filter behind the loop filter, after proper selection of parameters, can make the phase-locked loop quickly lock within the range where the phase-locked loop could not be locked originally.

Abstract: Provided is a BeiDou navigation satellite B1C signal capturing method, including: mixing a digital intermediate frequency signal with a local intermediate frequency carrier signal to obtain a baseband signal; obtaining a local BOC-like signal on a data channel and a local BOC-like signal on a pilot channel; processing the local BOC-like signal on the data channel and the local BOC-like signal on the pilot channel to obtain a cross-correlation result of the data channel and a cross-correlation result of the pilot channel; performing a linear operation on the cross-correlation result of each of the two channels through a pseudo-correlation function generator to eliminate a secondary peak in the cross-correlation result of each of the two channels, and obtain an optimized cross-correlation result of each of the two channels; and capturing a satellite signal based on the optimized cross-correlation result of each of the two channels.