Genome Writing:Current Progress and Related Applications

The ultimate goal of synthetic biology is to build customized cells or organisms to meet specific industrial or medical needs. The most important part of the customized cell is a synthetic genome. Advanced genomic writing technologies are required to build such an artificial genome. Recently, the partially-completed synthetic yeast genome project represents a milestone in this field. In this mini review, we briefly introduce the techniques for de novo genome synthesis and genome editing. Furthermore, we summarize recent research progresses and highlight several applications in the synthetic genome field. Finally, we discuss current challenges and future prospects. Keywords: Synthetic biology, Genome writing, Genome editing, Bioethics, Biosafet

Multifocal laser direct writing through spatial light modulation guided by scalable vector graphics

Multifocal laser direct writing (LDW) based on phase-only spatial light modulator (SLM) can realize flexible and parallel nanofabrication with high throughput potential. In this investigation, a novel approach of combining two-photon absorption, SLM and vector path guided by scalable vector graphics (SVG) has been developed and tested preliminarily, for fast, flexible and parallel nanofabrication. Three laser focuses are independently controlled with different paths, which are according to SVG, to optimize fabrication and promote time efficiency. The minimum structure width can be as low as 74 nm. Accompanied with a translation stage, a carp structure of 18.16 $\mu$m by 24.35 $\mu$m has been fabricated. This method shows the possibility of developing LDW techniques towards full-electrical system, and provides a potential way to efficiently engrave complex structures on nanoscales

A Simulation Method Based on Material-Drying Oven Integration for Hot Air Drying of Lentinus edodes and Its Application

In this paper, a simulation method based on material-drying oven integration was developed for the hot air-drying process of Lentinus edodes. First of all, the drying characteristics were investigated under different drying conditions, and drying kinetic models were obtained at different air temperatures, relative humidities (RHs) and air flow rates. Then, drying kinetic derivative models to predict the drying process under different working conditions were obtained and used to calculate water evaporation rate, and the rate of water evaporation was introduced into the heat and mass transfer equations to develop mathematical models based on material-drying oven integration. Using the models, the pattern of temporal changes in air temperature, RH and air flow rate at any position inside the oven and moisture ratio (MR) was obtained. Finally, the drying characteristics were worked out using the integrated models. Overall, significant non-uniformity occurred during the drying process. As drying proceeded, non-uniformity decreased. In the direction of air flow, non-uniformity was more significant at positions closer to the oven’s top and bottom. In the transverse direction, non-uniformity was more significant at positions closer to the middle. In summary, the simulation method for hot air-drying of Lentinus edodes is meaningful for guiding the structural design of the drying chamber, the optimization of the drying process and the improvement of the product quality

Genome-Wide Analysis of Lung Adenocarcinoma Identifies Novel Prognostic Factors and a Prognostic Score

Background and ObjectiveLung adenocarcinoma (LUAD) is the most common histological type of all lung cancers and is associated with genetic and epigenetic aberrations. The tumor, node, and metastasis (TNM) stage is the most authoritative indicator of the clinical outcome in LUAD patients in current clinical practice. In this study, we attempted to identify novel genetic and epigenetic modifications and integrate them as a predictor of the prognosis for LUAD, to supplement the TNM stage with additional information.MethodsA dataset of 445 patients with LUAD was obtained from The Cancer Genome Atlas database. Both genetic and epigenetic aberrations were screened for their prognostic impact on overall survival (OS). A prognostic score (PS) integrating all the candidate prognostic factors was then developed and its prognostic value validated.ResultsA total of two micro-RNAs, two mRNAs and two DNA methylation sites were identified as prognostic factors associated with OS. The low- and high-risk patient groups, divided by their PS level, showed significantly different OS (p < 0.001) and recurrence-free survival (RFS; p = 0.005). Patients in the early stages (stages I/II) and advanced stages (stages III/IV) of LUAD could be further subdivided by PS into four subgroups. PS remained efficient in stratifying patients into different OS (p < 0.001) and RFS (p = 0.005) when the low- and high-risk subgroups were in the early stages of the disease. However, there was only a significant difference in OS (p = 0.04) but not RFS (p = 0.2), between the low-risk and high-risk subgroups when both were in advanced stages.ConclusionPS, in combination with the TNM stage, provides additional precision in stratifying patients with significantly different OS and RFS prognoses. Further studies are warranted to assess the efficiency of PS and to explain the effects of the genetic and epigenetic aberrations observed in LUAD

Fractional variational problems depending on indefinite integrals and with delay

The aim of this paper is to exhibit a necessary and sufficient condition of optimality for functionals depending on fractional integrals and derivatives, on indefinite integrals and on presence of time delay. We exemplify with one example, where we nd analytically the minimizer

Study of half harmonic plasma waves in CO laser-plasma interactions

Half harmonic plasma waves, which can be generated by the two plasmon decay (TPD) and stimulated Raman scattering (SRS) instabilities in the regions with plasma density near nc/4, are studied experimentally in the interactions of an intense (I l≤10¹⁴W/cm²) CO₂ laser beam with an underdense plasma. The plasma is produced by focusing the CO₂ laser pulse (2 ns FWHM) onto a stabilized laminar nitrogen gas jet flowing from a Laval nozzle into low pressure helium. The plasma waves were investigated with ruby laser Thomson scattering. The absolute TPD and SRS instabilities were observed at pump intensities greater than 1.3 x 10¹³ W/cm² for a plasma with a density scale length of 2400 µm and an electron temperature of 300 eV. The difference predicted by the theory between plasma waves generated by the two plasma decay instability and those due to the stimulated Raman scattering deduced from theory are experimentally confirmed. Two plasmon decay is found to dominate the generation of half harmonic plasma waves. The TPD plasma waves appear in series of up to 8 bursts. The intensity distribution of the unsaturated TPD plasma waves is determined to be well described by linear theory. The intensity distribution of the saturated TPD plasma waves is shown to be governed by the saturation and quenching mechanisms. The angular distribution of ( 3/2)ω₀ emission deduced from the intensity distribution of the saturated TPD plasmons agrees well with the experimental results. The experimental evidence shows that the coupling of plasma waves to ion acoustic waves and the steepening of the density profile are the dominant saturation and quenching mechanism for the TPD instability.Science, Faculty ofPhysics and Astronomy, Department ofGraduat

Measurement of harmonics in a underdense CO₂ laser produced plasma

Second harmonic(2ω₀) and three halves harmonic(3/2ω₀) are studied in the interaction of CO₂ laser of frequency ω₀, with an underdense plasma. It is shown theoretically that filamentation can lead to sizable second harmonic generation. The 2ω₀-radiation is emitted into a forward directed cone, its angle determined by the wavelength of the fundamental radiation in the plasma filament. Experimental observations confirm the theoretical predications. Aside from the forward directed emission cone, non negligable 2ω₀ power is detected over a broad angular range in the backward direction showing a broadened red shifted spectrum. The dependence of the backward emitted 2ω₀-radiation on the plasma density, and the red shifted spectrum strongly support the argument that the backward emitted 2ω₀-radiation is related to the SBS(Stimulated Brillouin scattering) instability. Based on the wave vector matching conditions, the angular distribution of 3/2ω₀-radiation is predicted. The experimental results confirm the prediction. It is shown experimentally that the fusion of three plasma waves produced in the TPD(Two Plasma Decay) instability dominates the generation of 3/2ω₀-radiation when the incident beam energy is high.Science, Faculty ofPhysics and Astronomy, Department ofGraduat