Continuous Acetone–Butanol–Ethanol (ABE) Fermentation with in Situ Solvent Recovery by Silicalite-1 Filled PDMS/PAN Composite Membrane

The pervaporation (PV) performance of a thin-film silicalite-1 filled PDMS/PAN composite membrane was investigated in the continuous acetone–butanol–ethanol (ABE) production by a fermentation–PV coupled process. Results showed that continuous removal of ABE from the broth at three different dilution rates greatly increased both the solvent productivity and the glucose utilization rate, in comparison to the control batch fermentation. The high solvent productivity reduced the acid accumulation in the broths because most acids were reassimilated by cells for ABE production. Therefore, a higher total solvent yield of 0.37 g/g was obtained in the fermentation–PV coupled process, with a highly concentrated condensate containing 89.11–160.00 g/L ABE. During 268 h of the fermentation–PV coupled process, the PV membrane showed a high ABE separation factor of more than 30 and a total flux of 486–710 g/m2h. Membrane fouling was negligible for the three different dilution rates. The solution-diffusion model, especially the mass transfer equation, was proved to be applicable to this coupled process.<br/

Ionic Liquids as Bifunctional Cosolvents Enhanced CO₂ Conversion Catalysed by NADH-Dependent Formate Dehydrogenase

Efficient CO2 conversion by formate dehydrogenase is limited by the low CO2 concentrations that can be reached in traditional buffers. The use of ionic liquids was proposed as a manner to increase CO2 concentration in the reaction system. It has been found, however, that the required cofactor (NADH) heavily degraded during the enzymatic reaction and that acidity was the main reason. Acidity, indeed, resulted in reduction of the conversion of CO2 into formic acid and contributed to overestimate the amount of formic acid produced when the progression of the reaction was followed by a decrease in NADH absorbance (method N). Stability of NADH and the mechanism of NADH degradation was investigated by UV, NMR and by DFT calculations. It was found that by selecting neutral-basic ionic liquids and by adjusting the concentration of the ionic liquid in the buffer, the concentration of NADH can be maintained in the reaction system with little loss. Conversion of CO2 to methanol in BmimBF(4) (67.1%) was more than twice as compared with the conversion attained by the enzymatic reaction in phosphate buffer (24.3%)

Power optimization control of VSC-HVDC system for electromechanical oscillation suppression and grid frequency control

The voltage source converter (VSC) based high-voltage DC (HVDC) transmission system usually adopts damping and inertia control to quickly and independently adjust the active- and reactive- power, to improve the frequency stability and suppress the electromechanical oscillations of the power grid. This paper first analyzes the effect of the proportional-derivative (PD) controller parameter on the HVDC output power. The study shows that when the proportional-derivative controller parameter is increased to the limit value, HVDC will operate in the rapid power compensation (RPC) mode. Namely, according to the positive or negative polarities of the rotor speed deviation and the grid frequency deviation, the active- and reactive- power limits are used as the reference to rapidly control the output power, thereby minimizing the system’s unbalanced power, the rotor oscillation, and the frequency fluctuation. To this end, this paper proposes a coordinated active-/reactive- power control strategy for the VSC-HVDC system based on the RPC mode to suppress the grid electromechanical and frequency oscillations. The RPC mode enables HVDC to quickly release/absorb power, to compensate for system’s required power shortage or suppress excess power. When the speed deviation, the frequency deviation, and their rates of change meet the requirements, the damping control is used to make HVDC exit the RPC mode and further enhance the ability of the VSC-HVDC system. Simulation results prove the effectiveness of the proposed power optimization control strategy

Contribution of cysteine residues in the extracellular domain of the F protein of human respiratory syncytial virus to its function

The mature F protein of all known isolates of human respiratory syncytial virus (HRSV) contains fifteen absolutely conserved cysteine (C) residues that are highly conserved among the F proteins of other pneumoviruses as well as the paramyxoviruses. To explore the contribution of the cysteines in the extracellular domain to the fusion activity of HRSV F protein, each cysteine was changed to serine. Mutation of cysteines 37, 313, 322, 333, 343, 358, 367, 393, 416, and 439 abolished or greatly reduced cell surface expression suggesting these residues are critical for proper protein folding and transport to the cell surface. As expected, the fusion activity of these mutations was greatly reduced or abolished. Mutation of cysteine residues 212, 382, and 422 had little to no effect upon cell surface expression or fusion activity at 32°C, 37°C, or 39.5°C. Mutation of C37 and C69 in the F2 subunit either abolished or reduced cell surface expression by 75% respectively. None of the mutations displayed a temperature sensitive phenotype

Chasing ghosts : allopolyploid origin of Oxyria sinensis (Polygonaceae) from its only diploid congener and an unknown ancestor

This work was supported by grants from National Natural Science Foundation of China (31590821), National Key Project for Basic Research (2014CB954100), Ministry of Science and Technology of the People's Republic of China (2010DFA34610) and International Collaboration 111 Projects of China.Reconstructing the origin of a polyploid species is particularly challenging when an ancestor has become extinct. Under such circumstances the extinct donor of a genome found in the polyploid may be treated as a ‘ghost’ species in that its prior existence is recognised through the presence of its genome in the polyploid. In this study, we aimed to determine the polyploid origin of Oxyria sinensis (2n=40) for which only one congeneric species is known, i.e. diploid O. digyna (2n=14). Genomic in situ hybridization (GISH), transcriptome, phylogenetic and demographic analyses, and ecological niche modeling were conducted for this purpose. GISH revealed that O. sinensis comprised 14 chromosomes from O. digyna and 26 chromosomes from an unknown ancestor. Transcriptome analysis indicated that following divergence from O. digyna, involving genome duplication around 12 million years ago (Ma), a second genome duplication occurred approximately 6 Ma to give rise to O. sinensis. Oxyria sinensis was shown to contain homologous gene sequences divergent from those present in O. digyna in addition to a set that clustered with those in O. digyna. Coalescent simulations indicated that O. sinensis expanded its distribution approximately 6-7 Ma, possibly following the second polyploidization event, whereas O. digyna expanded its range much later. It was also indicated that the distributions of both species contracted and re-expanded during the Pleistocene climatic oscillations. Ecological niche modeling similarly suggested that both species experienced changes in their distributional ranges in response to Quaternary climatic changes. The extinction of the unknown ‘ghost’ tetraploid species implicated in the origin of O. sinensis could have resulted from superior adaptation of O. sinensis to repeated climatic changes in the region where it now occurs.PostprintPeer reviewe

Scaling-up Strategy as an Appropriate Approach for Sustainable New Town Development? Lessons from Wujin, Changzhou, China

China has achieved rapid urbanization and unprecedented economic booming over the past three decades. Numerous cities and towns dreamed of cloning the miracles of Shenzhen and Pudong, Shanghai, in terms of their international development. However, inappropriate development strategies have meant that the majority of fast expanding urban suburbs or newly developed towns suffer a high ratio of vacant dwellings in real estate markets and a massive loss of farmland. The frequent exposure of these empty cities to mass media or the public has urged urban governments to impose fiscal austerity. These unexpected and negative consequences of urban development have explicit conflicts with sustainability. This paper aims to provide a political economy view of these unsustainable outcomes of new development. To achieve this, the processes and agendas of new city or town planning in Wujin District, Changzhou City, are analyzed and evaluated from the perspective of scale theory. Extensive interviews conducted with local politicians at different levels, planners, real estate agents and local residents facilitate the interpretation of these processes and agendas. It is argued that the legends of Shenzhen and Pudong, Shanghai originate from a modified neoliberal capitalism intervention at the right time and place, with which other peer cities are not comparable. It is concluded that the scaling-up strategy is not appropriate for the local new town development of Wujin, which has led to unsustainable outcomes—empty cities and towns—and created important lessons for the sustainable development of Chinese cities

Comparative genomics reveals the hybrid origin of a macaque group

Although species can arise through hybridization, compelling evidence for hybrid speciation has been reported only rarely in animals. Here, we present phylogenomic analyses on genomes from 12 macaque species and show that the fascicularis group originated from an ancient hybridization between the sinica and silenus groups ~3.45 to 3.56 million years ago. The X chromosomes and low-recombination regions exhibited equal contributions from each parental lineage, suggesting that they were less affected by subsequent backcrossing and hence could have played an important role in maintaining hybrid integrity. We identified many reproduction-associated genes that could have contributed to the development of the mixed sexual phenotypes characteristic of the fascicularis group. The phylogeny within the silenus group was also resolved, and functional experimentation confirmed that all extant Western silenus species are susceptible to HIV-1 infection. Our study provides novel insights into macaque evolution and reveals a hybrid speciation event that has occurred only very rarely in primates

NTIRE 2024 Quality Assessment of AI-Generated Content Challenge

This paper reports on the NTIRE 2024 Quality Assessment of AI-Generated Content Challenge, which will be held in conjunction with the New Trends in Image Restoration and Enhancement Workshop (NTIRE) at CVPR 2024. This challenge is to address a major challenge in the field of image and video processing, namely, Image Quality Assessment (IQA) and Video Quality Assessment (VQA) for AI-Generated Content (AIGC). The challenge is divided into the image track and the video track. The image track uses the AIGIQA-20K, which contains 20,000 AI-Generated Images (AIGIs) generated by 15 popular generative models. The image track has a total of 318 registered participants. A total of 1,646 submissions are received in the development phase, and 221 submissions are received in the test phase. Finally, 16 participating teams submitted their models and fact sheets. The video track uses the T2VQA-DB, which contains 10,000 AI-Generated Videos (AIGVs) generated by 9 popular Text-to-Video (T2V) models. A total of 196 participants have registered in the video track. A total of 991 submissions are received in the development phase, and 185 submissions are received in the test phase. Finally, 12 participating teams submitted their models and fact sheets. Some methods have achieved better results than baseline methods, and the winning methods in both tracks have demonstrated superior prediction performance on AIGC

Desalination of effluents with highly concentrated salt by nanofiltration: From laboratory to pilot-plant

Nanofiltration (NF) has been widely used for treatment of industrial effluents, but very few work concerns NF process in concentrated saline solution, especially for NF-desalination aiming at permeation of monovalent salts and retention of organic solutes. In this study, NF270 membrane was chosen to treat model solutions and three industrial effluents with highly concentrated salt (crude iron dextran solution, iminodiacetic acid mother liquor, and raw soy sauce), showing that with increase of salt concentration, the retention of all the solutes decreased while concentration polarization was increased. In the presence of charged organic solutes, inorganic salt retention would decline, even negative retention of monovalent salt was found. Increasing pH would induce membrane swelling in saline solution, which might be caused by the higher local salt concentration around the membrane polymers at higher pH. As NF-desalination of industrial effluents with highly concentrated salt was scaled up from laboratory to pilot-plant, the dead-end stirred filtration at constant flux could provide some important information for pilot-plant tests, such as membrane selection, optimum operating parameters and mechanism analysis, but it was necessary to re-optimize operating mode and method for crossflow filtration at constant pressure, in order to control the concentration polarization at high salt concentration. (C) 2013 Elsevier B.V. All rights reserved