Oxygen uptake rate (OUR) control strategy for improving avermectin B1a production during fed-batch fermentation on industrial scale (150 m3)

Glucose metabolism plays a crucial role in the process of avermectin B1a biosynthesis. Controlling glucose feeding based on oxygen uptake rate (OUR) was established to improve the efficiency of avermectin B1a  production. The result showed that avermectin B1a production was greatly enhanced by OUR control strategy. In the glucose feeding phase, OUR was maintained at approximate 12 mmol/L/h, which was conducive to avermectin B1a biosynthesis. Using this OUR control strategy, an adequate supply of organic acid precursors produced avermectin B1a 5228 U/mL, which was 22.8% higher than that of the control (batch fermentation, 4256 U/mL) on industrial scale.Key words: Avermectin B1a, glucose feeding, oxygen uptake rate, industrial scale

Quasiatomic orbitals for ab initio tight-binding analysis

Wave functions obtained from plane-wave density-functional theory (DFT) calculations using norm-conserving pseudopotential, ultrasoft pseudopotential, or projector augmented-wave method are efficiently and robustly transformed into a set of spatially localized nonorthogonal quasiatomic orbitals (QOs) with pseudoangular momentum quantum numbers. We demonstrate that these minimal-basis orbitals can exactly reproduce all the electronic structure information below an energy threshold represented in the form of environment-dependent tight-binding Hamiltonian and overlap matrices. Band structure, density of states, and the Fermi surface are calculated from this real-space tight-binding representation for various extended systems (Si, SiC, Fe, and Mo) and compared with plane-wave DFT results. The Mulliken charge and bond order analyses are performed under QO basis set, which satisfy sum rules. The present work validates the general applicability of Slater and Koster\u27s scheme of linear combinations of atomic orbitals and points to future ab initio tight-binding parametrizations and linear-scaling DFT development

Efficient Multi-Pair IoT Communication with Holographically Enhanced Meta-Surfaces Leveraging OAM Beams: Bridging Theory and Prototype

Meta-surfaces, also known as Reconfigurable Intelligent Surfaces (RIS), have emerged as a cost-effective, low power consumption, and flexible solution for enabling multiple applications in Internet of Things (IoT). However, in the context of meta-surface-assisted multi-pair IoT communications, significant interference issues often arise amount multiple channels. This issue is particularly pronounced in scenarios characterized by Line-of-Sight (LoS) conditions, where the channels exhibit low rank due to the significant correlation in propagation paths. These challenges pose a considerable threat to the quality of communication when multiplexing data streams. In this paper, we introduce a meta-surface-aided communication scheme for multi-pair interactions in IoT environments. Inspired by holographic technology, a novel compensation method on the whole meta-surface has been proposed, which allows for independent multi-pair direct data streams transmission with low interference. To further reduce correlation under LoS channel conditions, we propose a vortex beam-based solution that leverages the low correlation property between distinct topological modes. We use different vortex beams to carry distinct data streams, thereby enabling distinct receivers to capture their intended signal with low interference, aided by holographic meta-surfaces. Moreover, a prototype has been performed successfully to demonstrate two-pair multi-node communication scenario operating at 10 GHz with QPSK/16-QAM modulation.Comment: Meta-surface, RIS, Internet-of-Things (IoT), Line-of-Sight (LoS), Orbital Angular Momentum (OAM), holographic communications, multi-use

Poly[[μ-aqua-bis­(μ-4,4′-bipyridine-κ2 N:N′)bis­(μ-3-hy­droxy­adamantane-1-carboxyl­ato-κ2 O:O′)bis­(3-hy­droxy­adamantane-1-carboxyl­ato-κO)dicobalt(II)] hepta­hydrate]

The title coordination compound, {[Co(C11H15O3)4(C10H8N2)2(H2O)]·7H2O}n, consists of a pair of CoII atoms, four 3-hy­droxy­adamantane-1-carboxyl­ate anions (L), one water mol­ecule, two bridging 4,4′-bipyridine (4,4′-bpy) ligands and seven uncoordinated water mol­ecules. Both of the CoII ions are coordinated in a distorted octa­hedral geometry. Four L ligands bind to each pair of CoII atoms in a plane, two of which bridge the two CoII atoms as bidentate groups while the other two coordinate to a single CoII atom in a monodentate mode. Two half-mol­ecules of 4,4′-bipyridine coordinate the CoII atoms from the upside and underside. The packing features extensice O—H⋯O hydrogen bonding

Flavonoids from Saussurea stella Maxim as superoxide scavengers and antioxidants

1201-120

Anthracenedione Derivatives as Anticancer Agents Isolated from Secondary Metabolites of the Mangrove Endophytic Fungi

In this article, we report anticancer activity of 14 anthracenedione derivatives separated from the secondary metabolites of the mangrove endophytic fungi Halorosellinia sp. (No. 1403) and Guignardia sp. (No. 4382). Some of them inhibited potently the growth of KB and KBv200 cells, among which compound 6 displayed strong cytotoxicity with IC50 values of 3.17 and 3.21 μM to KB and KBv200 cells, respectively. Furthermore, we demonstrate that the mechanism involved in the apoptosis induced by compound 6 is probably related to mitochondrial dysfunction. Additionally, the structure-activity relationships of these compounds are discussed

The thermodynamic and kinetic properties of hydrogen dimers on graphene

The thermodynamic and kinetic properties of hydrogen adatoms on graphene are important to the materials and devices based on hydrogenated graphene. Hydrogen dimers on graphene with coverages varying from 0.040 to 0.111 ML (1.0 ML $= 3.8\times10^{15}$cm$^{-2}$) were considered in this report. The thermodynamic and kinetic properties of H, D and T dimers were studied by ab initio simulations. The vibrational zero-point energy corrections were found to be not negligible in kinetics, varying from 0.038 (0.028, 0.017) to 0.257 (0.187, 0.157) eV for H (D, T) dimers. The isotope effect exhibits as that the kinetic mobility of a hydrogen dimer decreases with increasing the hydrogen mass. The simulated thermal desorption spectra with the heating rate $\alpha = 1.0$ K/s were quite close to experimental measurements. The effect of the interaction between hydrogen dimers on their thermodynamic and kinetic properties were analyzed in detail.Comment: submitted to Surface Scienc