Covering: 2013 to June 2018
Heterologous expression of natural product biosynthetic pathways is of increasing interest in microbial biotechnology, drug discovery and optimization. It empowers not ...only the robust production of valuable biomolecules in more amenable heterologous hosts but also permits the generation of novel analogs through biosynthetic engineering. This strategy also facilitates the discovery of novel bioactive compounds following the functional expression of cryptic biosynthetic gene clusters (BGCs) from fastidious original producers or metagenomic DNA in surrogate hosts, thus facilitating genome mining in the post-genomic era. This review discusses recent advances and trends pertaining to the heterologous production of bacterial natural products, with an emphasis on new techniques, heterologous hosts, and novel chemistry since 2013.
The review highlights the 2013-2018 literature on the heterologous expression of bacterial natural product biosynthetic pathways and emphasises new techniques, heterologous hosts, and novel chemistry.
On Biometrics With Eye Movements Youming Zhang; Juhola, Martti
IEEE journal of biomedical and health informatics,
2017-Sept., 2017-09-00, 2017-9-00, 20170901, Volume:
21, Issue:
5
Journal Article
Peer reviewed
Open access
Eye movements are a relatively novel data source for biometric identification. When video cameras applied to eye tracking become smaller and more efficient, this data source could offer interesting ...opportunities for the development of eye movement biometrics. In this paper, we study primarily biometric identification as seen as a classification task of multiple classes, and secondarily biometric verification considered as binary classification. Our research is based on the saccadic eye movement signal measurements from 109 young subjects. In order to test the data measured, we use a procedure of biometric identification according to the one-versus-one (subject) principle. In a development from our previous research, which also involved biometric verification based on saccadic eye movements, we now apply another eye movement tracker device with a higher sampling frequency of 250 Hz. The results obtained are good, with correct identification rates at 80-90% at their best.
As a highly stable band gap semiconductor, antimonene is an intriguing two‐dimensional (2D) material in optoelectronics. However, its short layer distance and strong binding energy make it ...challenging to prepare high‐quality large 2D antimonene; therefore, its predicted tunable band gap has not been experimentally confirmed. Now, an approach to prepare smooth and large 2D antimonene with uniform layers that uses a pregrinding and subsequent sonication‐assisted liquid‐phase exfoliation process has been established. Mortar pregrinding provides a shear force along the layer surfaces, forming large, thin antimony plates, which can then easily be exfoliated into smooth, large antimonene, avoiding long sonication times and antimonene destruction. The resulting antimonene also enabled verification of the tunable band gap from 0.8 eV to 1.44 eV. Hole extraction and current enhancement by about 30 % occurred when the antimonene was used as a hole transport layer in perovskite solar cells.
Chasing antimonene: The Group 15 2D material antimonene was successfully prepared by pregrinding and a subsequent liquid‐phase exfoliation process. The uniform antimonene thus obtained provided an opportunity for an experimental study of the band gap dependence on the antimonene thickness, indicating that the band gap is finely tunable between 0.8 eV and 1.44 eV.
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Leaf chlorophyll content (LCC) is one of the most important factors affecting photosynthetic capacity and nitrogen status, both of which influence crop harvest. However, the development of rapid and ...nondestructive methods for leaf chlorophyll estimation is a topic of much interest. Hence, this study explored the use of the machine learning approach to enhance the estimation of leaf chlorophyll from spectral reflectance data. The objective of this study was to evaluate four different approaches for estimating the LCC of apple tree leaves at five growth stages (the 1st, 2nd, 3rd, 4th and 5th growth stages): (1) univariate linear regression (ULR); (2) multivariate linear regression (MLR); (3) support vector regression (SVR); and (4) random forest (RF) regression. Samples were collected from the leaves on the eastern, western, southern and northern sides of apple trees five times (1st, 2nd, 3rd, 4th and 5th growth stages) over three consecutive years (2016–2018), and experiments were conducted in 10–20-year-old apple tree orchards. Correlation analysis results showed that LCC and ST, LCC and vegetation indices (VIs), and LCC and three edge parameters (TEP) had high correlations with the first-order differential spectrum (FODS) (0.86), leaf chlorophyll index (LCI) (0.87), and (SDr − SDb)/ (SDr + SDb) (0.88) at the 3rd, 3rd, and 4th growth stages, respectively. The prediction models of different growth stages were relatively good. The MLR and SVR models in the LCC assessment of different growth stages only reached the highest R2 values of 0.79 and 0.82, and the lowest RMSEs were 2.27 and 2.02, respectively. However, the RF model evaluation was significantly better than above models. The R2 value was greater than 0.94 and RMSE was less than 1.37 at different growth stages. The prediction accuracy of the 1st growth stage (R2 = 0.96, RMSE = 0.95) was best with the RF model. This result could provide a theoretical basis for orchard management. In the future, more models based on machine learning techniques should be developed using the growth information and physiological parameters of orchards that provide technical support for intelligent orchard management.
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The three primary colour model, i.e., red, green, and blue model, based on the colour perception of the human eye, has been widely used in colour imaging. The most common approach for obtaining ...colour information is to use a Bayer colour filter, which filters colour light with four pixels of an imaging sensor to form an effective colour pixel. However, its energy utilization efficiency and colour collection efficiency are limited to a low level due to the three-channel filtering nature. Here, by employing an inverse-design method, we demonstrate a pixel-level metasurface-based Bayer-type colour router that presents peak colour collection efficiencies of 58%, 59%, and 49% for red, green and blue light, and an average energy utilization efficiency as high as 84% over the visible region (400 nm-700 nm), which is twice as high as that of a commercial Bayer colour filter. Furthermore, by using a 200 µm × 200 µm metasurface-based colour router sample working with a monochromatic imaging sensor, colour imaging is further realized, obtaining an image intensity twice that achieved by a commercial Bayer colour filter. Our work innovates the mechanism of high-efficiency spectrum information acquisition, which is expected to have promising applications in the development of next-generation imaging systems.
Near‐infrared (NIR) emitting materials have attracted considerable attention because of their potential applications in organic light emitting diodes, bioimaging, military, etc. The research on ...NIR‐emitting materials and devices is motivated by fundamental and practical application demands. In these developed NIR‐emitting materials, transition metal complexes, and thermally activated delayed fluorescence (TADF) molecules, which can harvest triplet excitons, have exhibited significant potential because their theoretical internal quantum efficiency can reach 100%. Herein, the development of these NIR‐emitting materials of transition metal complexes and TADF molecules is reviewed and, furthermore, a clear outlook for a broad range of applications in many disciplinary areas is provided.
Recent development of the near‐infrared (NIR) emitting materials of transition metal complexes and thermally activated delayed fluorescence molecules is reviewed here. Furthermore, a clear outlook for a broad range of applications in different areas is provided.
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