Calcium chloride improve ethanol production in recombinant Zymomonas mobilis

The T7-expression system has been very useful for protein expression in Escherichia coli. Here, a T7- expression transposon was constructed, which allowed simple construction of T7-expression Zymomonas mobilis. This transposon contained the T7 RNA polymerase being driven by the gap promoter from Z. mobilis. The T7-expression fadK genomes were introduced into Z. mobilis ATCC 31821 in order to increase ethanol production. The recombinant bacteria were named as Z.M.F-1, Z.M.F-2, Z.M.F-3, and Z.M.F-4. However, Z.M.F-4 had the highest ability of producing ethanol by selection. Compared with Z. mobilis ATCC 3182, there was 7% increase in ethanol production for Z.M.F-4 with corn hydrolyaztes as fermentation medium. The 16 mmolL-1 supplement of calcium chloride could significantly improve the ethanol production. This was also clearly demonstrated by a variety of kinetic parameter values over time in Z.M.F-4 under high sugar osmotic stress. Calcium chloride not only increased the fermentation ability but also improved the stability of cell membrane.Key words: Calcium chloride, fadK, fermentation, Zymomonas mobilis

A toolbox of Cre-dependent optogenetic transgenic mice for light-induced activation and silencing

We report on wide-field optically detected magnetic resonance imaging of nitrogen-vacancy centers (NVs) in type IIa polycrystalline diamond. These studies reveal a heterogeneous crystalline environment that produces a varied density of NV centers, including preferential orientation within some individual crystal grains, but preserves long spin coherence times. Using the native NVs as nanoscale sensors, we introduce a three-dimensional strain imaging technique with high sensitivity (<10[superscript -5] Hz[superscript –1/2]) and diffraction-limited resolution across a wide field of view.Allen Institute for Brain ScienceHoward Hughes Medical Institut

Atomic Structure Evolution of Pt–Co Binary Catalysts: Single Metal Sites versus Intermetallic Nanocrystals

Due to their exceptional catalytic properties for the oxygen reduction reaction (ORR) and other crucial electrochemical reactions, PtCo intermetallic nanoparticle (NP) and single atomic (SA) Pt metal site catalysts have received considerable attention. However, their formation mechanisms at the atomic level during high-temperature annealing processes remain elusive. Here, the thermally driven structure evolution of Pt–Co binary catalyst systems is investigated using advanced in situ electron microscopy, including PtCo intermetallic alloys and single Pt/Co metal sites. The pre-doping of CoN4 sites in carbon supports and the initial Pt NP sizes play essential roles in forming either Pt3Co intermetallics or single Pt/Co metal sites. Importantly, the initial Pt NP loadings against the carbon support are critical to whether alloying to L12-ordered Pt3Co NPs or atomizing to SA Pt sites at high temperatures. High Pt NP loadings (e.g., 20%) tend to lead to the formation of highly ordered Pt3Co intermetallic NPs with excellent activity and enhanced stability toward the ORR. In contrast, at a relatively low Pt loading (<6 wt%), the formation of single Pt sites in the form of PtC3N is thermodynamically favorable, in which a synergy between the PtC3N and the CoN4 sites could enhance the catalytic activity for the ORR, but showing insufficient stability

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

How Fencing Affects the Soil Quality and Plant Biomass in the Grassland of the Loess Plateau

Overgrazing is a severe problem in several regions in Northwestern China and has caused serious land degradation. Secondary natural succession plays an important role in the accumulation of soil carbon and nitrogen contents. Estimating the effects of grazing exclusion on soil quality and plant diversity will improve our understanding of the succession process after overgrazing and promote judicious management of degraded pastures. This experiment was designed to measure soil properties and plant diversity following an age chronosequence of grasslands (ages ranged from one year, 12 years, 20 years, and 30 years) in Northwestern China. The results showed that continuous fencing resulted in a considerable increase in plant coverage, plant biomass (above- and below-ground biomass), and plant diversity, which can directly or indirectly improve the accumulation of soil organic carbon and total nitrogen content. The plant coverage and the above- and below-ground biomass linearly increased along the succession time, whereas soil organic C and N contents showed a significant decline in the first 12 years and, subsequently, a significant increase. The increased plant biomass caused an increase in soil organic carbon and soil total nitrogen. These results suggested that soil restoration and plant cover were an incongruous process. Generally, soil restoration is a slow process and falls behind vegetation recovery after grazing exclusion. Although the accumulation of soil C and N stocks needed a long term, vegetation restoration was a considerable option for the degraded grassland due to the significant increase of plant biomass, diversity, and soil C and N stocks. Therefore, fencing with natural succession should be considered in the design of future degraded pastures

Generation and Transmission Expansion Planning Based on Game Theory in Power Engineering

AbstractThe unbundling of power generation and transmission in the restructured power system makes the coordinated planning of power generation and transmission a new challenge for both generation and transmission enterprises. In this paper, a single-stage deterministic model is proposed to study the interaction of strategies between both enterprises, based on the game analysis of generation and transmission planning. Then, Cournot model is used to simulate the expansion strategies of generation and transmission enterprises. The equilibrium is obtained by using the Mixed Complementarity Problem approach. In addition, the proposed model is applied to a three-bus system, which verifies the feasibility of this model

Ultrathin Zincophilic Interphase Regulated Electric Double Layer Enabling Highly Stable Aqueous Zinc-Ion Batteries

Highlights Electric double-layer regulation enabled by an ultrathin multifunctional solid electrolyte interphase layer with zincophilicity and rapid transport kinetics. Lowered potential drop over the Helmholtz layer and suppressed diffuse layer. Inhibited side reactions and uniform zinc deposition

Factors associated with oral health service utilization among young people in southern China

Abstract Objectives To identify the patterns and influencing factors of oral health service utilization among college students, and further to provide scientific evidence for policy making on oral health education and behavioral interventions for the college population. Methods The study population was college students in Southern China. Totally 678 students participated in the survey. A self-designed questionnaire based on Anderson’s model (predisposing factors, enabling factors, need factors) was used to survey college students. Descriptive statistics, χ2 test, and logistic regression were used to analyze influence factors of oral health service utilization among college students. Results The utilization rate of oral health service in the past 12 months was 30.2%. The primary type of oral health service was treatment (59.6%), and only 12.8% were for prevention. There were 39% of the participants having oral health diseases, of which dental caries (25.7%) and oral bleeding (22.2%) were the main problems. The results from logistic regression analysis revealed that students with better beliefs (OR = 1.84, 95% CI:=1.02–3.43), frequent consumption of sugary drinks (OR = 2.90, 95% CI:=1.90–4.47), teeth brushing frequency > = 2 times per day (OR = 2.09, 95% CI = 1.24–3.61), frequent floss utilization (OR = 2.63, 95% CI = 1.21–5.76), dental caries (OR = 2.07, 95% CI = 1.35–3.17) used oral health services higher, while those lived in rural areas (OR:0.52, 95% CI = 0.34–0.80), and had only a fair concern (OR = 0.48, 95% CI = 0.31–0.74) or no concern (OR = 0.26, 95% CI = 0.08–0.67) on oral health utilized oral health services lower. Conclusions Chinese college students demonstrate some knowledge and attitudes towards oral health. However, they tend to neglect oral hygiene and have limited understanding of their own oral issues. Furthermore, the utilization of oral services, such as treatment, remains remarkably low, despite the availability of long-term and favorable health insurance policies. The utilization of oral health services among college students is influenced by various factors, including residing in rural areas, consuming sugary beverages on a daily basis, brushing teeth at least twice a day, and practicing flossing