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Pass-back chain extension expands multimodular assembly line biosynthesis.
Modular nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) enzymatic assembly lines are large and dynamic protein machines that generally effect a linear sequence of catalytic cycles. Here, we report the heterologous reconstitution and comprehensive characterization of two hybrid NRPS-PKS assembly lines that defy many standard rules of assembly line biosynthesis to generate a large combinatorial library of cyclic lipodepsipeptide protease inhibitors called thalassospiramides. We generate a series of precise domain-inactivating mutations in thalassospiramide assembly lines, and present evidence for an unprecedented biosynthetic model that invokes intermodule substrate activation and tailoring, module skipping and pass-back chain extension, whereby the ability to pass the growing chain back to a preceding module is flexible and substrate driven. Expanding bidirectional intermodule domain interactions could represent a viable mechanism for generating chemical diversity without increasing the size of biosynthetic assembly lines and challenges our understanding of the potential elasticity of multimodular megaenzymes
Grey GERT Network Model of Equipment Lifetime Evaluation Based on Small Samples
The reliability evaluation of high reliability and long life equipment is widely concerned in recent decades. Enough failure samples of these kinds of equipment are not easy or economic to obtain in reliability test, in addition, experience information is sometimes inaccurate or uncertainty. To overcome the deficiency in traditional method which requires large numbers of samples, a quantitative analysis model of equipment reliability evaluation is proposed in this paper in view of the few failure data of equipment life tests. GERT network is introduced to describe the kinds of working states of the equipment system and random process of equipment state transition choice after stress impact of single component. Considering the uncertainty and inaccuracy of the statistical data and experience information, the parameters of GERT network are represented by interval grey number. The system equivalent transfer function could be obtained by GERT matrix solving algorithm, and the reliability evaluation of equipment system can be realized. The case study results show that the equipment reliability evaluation Grey-GERT model based on small samples would save much time with little accuracy losing. Besides, the study provides a new thinking for reliability accelerated life test
FUNCTIONAL LOCALIZATION OF PANIC PSYCHOLOGICAL TEST BASED ON FUNCTIONAL MAGNETIC RESONANCE LIE DETECTION
FUNCTIONAL LOCALIZATION OF PANIC PSYCHOLOGICAL TEST BASED ON FUNCTIONAL MAGNETIC RESONANCE LIE DETECTION
VLBA 24 and 43 GHz observations of massive binary black hole candidate PKS 1155+251
PKS 1155+251 is a radio-loud quasar source at z=0.203. Observations using
very long baseline interferometry (VLBI) at ~2, 5, 8 and 15 GHz show that the
structure of the radio source is quite complicated on parsec scales and that
the outer hot spots are apparently undergoing a significant contraction.
Because these results cannot be fully explained based on the compact symmetric
object (CSO) scenario with a radio core located between the northern and
southern complexes, we made observations with the Very Long Baseline Array
(VLBA) at 24 and 43 GHz to search for compact substructures and alternative
interpretations. The results show that the radio core revealed in the previous
VLBI observations remains compact with a flat spectrum in our
sub-milli-arcsecond--resolution images; the northern lobe emission becomes
faint at 24 GHz and is mostly resolving out at 43 GHz; the southern complex is
more bright but has been resolved into the brightest southern-end (S1) and jet
or tail alike components westwards. Explaining the southern components aligned
westward with a standard CSO scenario alone remains a challenge. As for the
flatter spectral index of the southern-end component S1 between 24 and 43 GHz
in our observations and the significant 15 GHz VLBA flux variability of S1, an
alternative scenario is that the southern complex may be powered by a secondary
black hole residing at S1. But more sensitive and high-resolution VLBI
monitoring is required to discriminate the CSO and the binary black hole
scenarios.Comment: 7 pages, 3 figures, accepted by MNRA
Ghost translation
Artificial intelligence has recently been widely used in computational
imaging. The deep neural network (DNN) improves the signal-to-noise ratio of
the retrieved images, whose quality is otherwise corrupted due to the low
sampling ratio or noisy environments. This work proposes a new computational
imaging scheme based on the sequence transduction mechanism with the
transformer network. The simulation database assists the network in achieving
signal translation ability. The experimental single-pixel detector's signal
will be `translated' into a 2D image in an end-to-end manner. High-quality
images with no background noise can be retrieved at a sampling ratio as low as
2%. The illumination patterns can be either well-designed speckle patterns for
sub-Nyquist imaging or random speckle patterns. Moreover, our method is robust
to noise interference. This translation mechanism opens a new direction for
DNN-assisted ghost imaging and can be used in various computational imaging
scenarios.Comment: 10 pages, 8 figure
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