[Effect of intestinal nitrate on growth of Klebsiella pneumoniae and its regulatory mechanism]

OBJECTIVE

To explore the effect of intestinal nitrates on the growth of Klebsiella pneumoniae and its regulatory mechanisms.

METHODS

K. pneumoniae strains with nitrate reductase narG and narZ single or double gene knockout or with NarXL gene knockout were constructed and observed for both aerobic and anaerobic growth in the presence of KNO3 using an automated bacterial growth analyzer and a spectrophotometer, respectively. The mRNA expressions of narG and narZ in K. pneumoniae in anaerobic cultures in the presence of KNO3 and the effect of the binary regulatory system NarXL on their expresisons were detected using qRT-PCR. Electrophoretic mobility shift assays (EMSA) and MST analysis were performed to explore the specific regulatory mechanisms of NarXL in sensing and utilizing nitrates. Competitive experiments were conducted to examine anaerobic growth advantages of narG and narZ gene knockout strains of K. pneumoniae in the presence of KNO3.

RESULTS

The presence of KNO3 in anaerobic conditions, but not in aerobic conditions, promoted bacterial growth more effectively in the wild-type K. pneumoniae strain than in the narXL gene knockout strain. In anaerobic conditions, the narXL gene knockout strain showed significantly lowered mRNA expressions of narG and narZ (P < 0.0001). EMSA and MST experiments demonstrated that the NarXL regulator could directly bind to narG and narZ promoter regions. The wild-type K. pneumoniae strain in anaerobic cultures showed significantly increased expressions of narG and narZ mRNAs in the presence of KNO3 (P < 0.01), and narG gene knockout resulted in significantly attenuated anaerobic growth and competitive growth abilities of K. pneumoniae in the presence of KNO3 (P < 0.01).

CONCLUSION

The binary regulatory system NarXL of K. pneumoniae can sense changes in intestinal nitrate concentration and directly regulate the expression of nitrate reductase genes narG and narZ to promote bacterial growth.

Dryness stress weakens the sustainability of global vegetation cooling

Dryness stress can limit vegetation growth, and the cooling potential of vegetation will also be strongly influenced. However, it is still unclear how dryness stress feedback weakens the sustainability of vegetation-based cooling. Based on the long-time series of multi-source remote sensing product data for the period 2001-2020, the relative contribution rate, and the method of decoupling and boxing, we determined that greening will likely mitigate global warming by 0.065 ± 0.009 °C/a, but nearly 47 % of the area is unsustainable. This phenomenon is strongly related to dryness stress. The restricted area of soil moisture (SM: 68.35 %) to vegetation is larger than that of the atmospheric vapor pressure deficit (VPD: 34.19 %). With the decrease in SM, vegetation will decrease by an average of 14.9 %, and with the increase in VPD, vegetation will decrease by 3.8 %. With the continuous increase in the dryness stress area, the sustainability of the vegetation cooling effect will be threatened in an area of about 21.03 million km2, which is equivalent to the area of North America. Specifically, we found that with the decrease in SM and the increase in VPD, the contribution of vegetation to the cooling effect has been weakened by 10.8 %. This conclusion confirms that dryness stress will threaten the sustainability of vegetation-based climate cooling and provides further insight into the effect of dryness stress on vegetation cooling.

Removal of Fermentation Inhibitors from Sugarcane Bagasse Hydrolysate via Post-cross-linked Hydrophilic-Hydrophobic Interpenetrating Polymer Networks

The efficient and economical removal of fermentation inhibitors from the complex system of biomass hydrolysate was one of the basics and keys in bio-chemical transformation. In this work, post-cross-linked hydrophilic-hydrophobic interpenetrating polymer networks (PMA/PS_pc IPNs and PAM/PS_pc IPNs) were proposed to remove fermentation inhibitors from sugarcane bagasse hydrolysate for the first time. PMA/PS_pc and PAM/PS_pc IPNs can obviously enhance the adsorption performance towards fermentation inhibitors due to their higher surface area and hydrophilic-hydrophobic synergetic surface properties, especially PMA/PS_pc IPNs has higher selectivity coefficients of 4.57, 4.63, 4.85, 16.0, 49.43, and 22.69, and higher adsorption capacity of 24.7 mg/g, 39.2 mg/g, 52.4 mg/g, 9.1 mg/g, 13.2 mg/g, and 144.9 mg/g towards formic acid, acetic acid, levulinic acid (LA), 5-hydroxymethylfurfural (HMF), furfural, and acid-soluble lignin (ASL), respectively, in a lower total sugar loss of 2.03%. The adsorption kinetics and isotherm of PMA/PS_pc IPNs were studied to elucidate its adsorption behavior towards fermentation inhibitors. In addition, the cyclic utilization property of PMA/PS_pc IPNs was stable. Synthesizing PMA/PS_pc IPNs is a new strategy to provide an efficient adsorbent for the removal of fermentation inhibitors from lignocellulosic hydrolysate.

A carbon-neutrality-capactiy index for evaluating carbon sink contributions

The accurate determination of the carbon-neutrality capacity (CNC) of a region is crucial for developing policies related to emissions and climate change. However, a systematic diagnostic method for determining the CNC that considers the rock chemical weathering carbon sink (RCS) is lacking. Moreover, it is challenging but indispensable to establish a fast and practical index model to determine the CNC. Here, we selected Guizhou as the study area, used the methods for different types of carbon sinks, and constructed a CNC index (CNCI) model. We found that: (1) the carbonate rock chemical weathering carbon sink flux was 30.3 t CO₂ km^-2 yr^-1. Guizhou accounted for 1.8% of the land area and contributed 5.4% of the carbonate chemical weathering carbon sink; (2) the silicate rock chemical weathering carbon sink and its flux were 1.44 × 10³ t CO₂ and 2.43 t CO₂ km^-2 yr^-1, respectively; (3) the vegetation-soil ecosystem carbon sink and its flux were 1.37 × 10⁸ t CO₂ and 831.70 t CO₂ km^-2 yr^-1, respectively; (4) the carbon emissions (CEs) were 280 Tg CO₂, about 2.8% of the total for China; and (5) the total carbon sinks in Guizhou were 160 Tg CO₂, with a CNCI of 57%, which is 4.8 times of China and 2.1 times of the world. In summary, we conducted a systematic diagnosis of the CNC considering the RCS and established a CNCI model. The results of this study have a strong implication and significance for national and global CNC determination and gap analysis.

Extraction of Eucommia ulmoides gum and microbial lipid from Eucommia ulmoides Oliver leaves by dilute acid hydrolysis

OBJECTIVES

Eucommia ulmoides gum (EUG) is an important natural biomass rubber material, which is usually extracted from Eucommia ulmoides Oliver (EUO). In the extraction process of EUG, pretreatment is the most important step which can efficiently damage EUG-containing cell wall and improve yield of EUG.

RESULTS

The FT-IR, XRD, DSC and TG results showed that the thermal properties and structure of the EUG from the dilute acids hydrolysis residue are similar with that of the EUG directly extracted from EUO leaves (EUGD). EUO leaves hydrolysis with AA had the highest EUG yield (16.1%), which was higher than the EUGD yield (9.5%). In the case of the EUO leaves hydrolysis with 0.33 ~ 0.67 wt% of acetic acid (AA), the total sugar was stable in the range of 26.82-27.67 g/L. Furthermore, the EUO leaves acid hydrolysate (AA as reagent) was used as carbon sources for lipid-producing fermentation by Rhodosporidium toruloides. After 120 h of fermentation, the biomass, lipid content and lipid yield were 12.13 g/L, 30.16% and 3.64 g/L, respectively. The fermentation results indicated organic acids were no toxic for Rhodosporidium toruloides and the AA also could be used as carbon source for fermentation.

Fermentation performance of oleaginous yeasts on Eucommia ulmoides Oliver hydrolysate: Impacts of the mixed strains fermentation

This present study mainly focused on the investigation and optimization of the fermentation performance of oleaginous yeasts on Eucommia ulmoides Oliver hydrolysate (EUOH), which contains abundant and diverse sugars. More importantly, the impacts of the mixed strains fermentation compared with the single strain fermentation were analyzed and evaluated, through systematic investigations of substrate metabolism, cell growth, polysaccharide and lipid production, COD and ammonia-nitrogen removals. It was found that the mixed strains fermentation could effectively promote a more comprehensive and thorough utilization of the various sugars in EUOH, greatly improve COD removal effect, biomass and yeast polysaccharide production, but could not significantly improve the overall lipid content and ammonia nitrogen removal effect. In this study, when the two strains with the highest lipid content (i.e. L. starkeyi and R. toruloides) were mixed-cultured, the maximum lipid yield of 3.82 g/L was achieved, and the yeast polysaccharide yield, COD and ammonia-nitrogen removal rates of the fermentation (LS+RT) were 1.64 g/L, 67.4% and 74.9% respectively. When the strain with the highest polysaccharide content (i.e. R. toruloides) was mixed-cultured with the strains with strong growth activity (i.e. T. cutaneum and T. dermatis), a large amount of yeast polysaccharides could be obtained, which were 2.33 g/L (RT+TC) and 2.38 g/L (RT+TD) respectively. And the lipid yield, COD and ammonia-nitrogen removal rates of the fermentation (RT+TC), (RT+TD) were 3.09 g/L, 77.7%, 81.4% and 2.54 g/L, 74.9%, 80.4%, respectively.

Synthesis of Hyper-cross-linked Nonpolar Polystyrene Divinylbenzene Resins by Pendent Vinyl Groups and Application to the Decolorization of Cane Molasses

Cane molasses is a by-product of sugar industry. It is widely used in fermentation field, but pigment compounds affect its further application. In this study, nonpolar hyper-cross-linked adsorption resins (HCARs) were synthesized by pendent vinyl groups cross-linking reaction, and were applied to decolorization of molasses. The correlation between the structure and the decolorization performance of HCARs was studied, and the results showed that the Brunauer-Emmett-Teller (BET) surface area and the pore volume of the resin significantly increased to 574.4 m²·g^-1 and 1.40 cm³·g^-1 after the Friedel-Crafts alkylation reaction with a catalyst dosage of 2.25% at 343 K for 7 h. Furthermore, the decolorization rate of molasses by the HCAR was 74%, and recycle decolorization performance of the resin was stable. The adsorption kinetics results showed that the pseudo-second-order dynamic model could more realistically reflect the decolorization mechanism of molasses on HCARs, and liquid film diffusion is the main rate-limiting step. The results of fixed-bed experiments show that D-ST-DVB resin has a good decolorization effect and recycling ability. Therefore, it is a feasible strategy for the decolorization of molasses with nonpolar HCAR.

Depinning phase transition of antiferromagnetic skyrmions with quenched disorder

Antiferromagnetic skyrmions are considered to be promising information carriers due to their attractive properties. Therefore, the pinning phenomenon of antiferromagnetic skyrmions is of great significance. With the Landau-Lifshitz-Gilbert equation, we simulate the nonstationary dynamic behaviors of skyrmions driven by currents in a chiral antiferromagnetic thin film with quenched disorder. Based on the dynamic scaling forms, the critical current and static and dynamic critical exponents of the depinning phase transition are accurately determined. A theoretical analysis using Thiele's approach is presented in comparison with the numerical simulation. Unlike the ferromagnetic skyrmions, the critical current of the antiferromagnetic skyrmions is very sensitive to a small nonadiabatic coefficient. This is important for manipulating antiferromagnetic skyrmions and designing novel information processing devices.

High-resolution mapping of the global silicate weathering carbon sink and its long-term changes

Climatic and non-climatic factors affect the chemical weathering of silicate rocks, which in turn affects the CO₂ concentration in the atmosphere on a long-term scale. However, the coupling effects of these factors prevent us from clearly understanding of the global weathering carbon sink of silicate rocks. Here, using the improved first-order model with correlated factors and non-parametric methods, we produced spatiotemporal data sets (0.25° × 0.25°) of the global silicate weathering carbon-sink flux (SCSF_α ) under different scenarios (SSPs) in present (1950-2014) and future (2015-2100) periods based on the Global River Chemistry Database and CMIP6 data sets. Then, we analyzed and identified the key regions in space where climatic and non-climatic factors affect the SCSF_α . We found that the total SCSF_α was 155.80 ± 90 Tg C yr^-1 in present period, which was expected to increase by 18.90 ± 11 Tg C yr^-1 (12.13%) by the end of this century. Although the SCSF_α in more than half of the world was showing an upward trend, about 43% of the regions were still showing a clear downward trend, especially under the SSP2-4.5 scenario. Among the main factors related to this, the relative contribution rate of runoff to the global SCSF_α was close to 1/3 (32.11%), and the main control regions of runoff and precipitation factors in space accounted for about 49% of the area. There was a significant negative partial correlation between leaf area index and silicate weathering carbon sink flux due to the difference between the vegetation types. We have emphasized quantitative analysis the sensitivity of SCSF_α to critical factors on a spatial grid scale, which is valuable for understanding the role of silicate chemical weathering in the global carbon cycle.

The impact of avoidant attachment on marital satisfaction of Chinese married people: Multiple mediating effect of spousal support and coping tendency

In this study, the relationship between attachment avoidance and marital satisfaction of Chinese married people as well as the multiple mediating role of spousal support and coping tendency were explored. A model was developed using data of a sample of 510 Chinese married people. Four scales (the Experience of Close Relationships Scale, the Support Scale in Intimate Relationships, the Simple Coping Style Scale, and the Olson Marital Quality Questionnaire) were used to assess attachment avoidance, spousal support, coping tendency, and marital satisfaction, respectively. The results of correlation analysis showed that attachment avoidance was significantly negatively correlated with spousal support, coping tendency, and marital satisfaction. Spousal support was significantly positively correlated with both coping tendency and marital satisfaction. Coping tendency was significantly positively correlated with marital satisfaction. The mediation model indicated significant mediating effects of spousal support and coping tendency between attachment avoidance and marital satisfaction, respectively, where the mediating path of spousal support exerted the largest effect. The multiple mediating effect of attachment avoidance → spousal support → coping tendency → marital satisfaction was also significant. Chinese married people with high levels of attachment avoidance might perceive lower levels of spousal support and are therefore more inclined to employ negative coping when handling conflicts, which lowers marital satisfaction.

Selective hydrogenation of butyl levulinate to γ-valerolactone over sulfonated activated carbon-supported SnRuB bifunctional catalysts

The sulfonated activated carbon (SAC) supported SnRuB catalyst was developed through the co-impregnation followed by a chemical reduction process and applied for BL hydrogenation to GVL for the first time.

Factors Affecting the Catalytic Efficiency and Synergism of Xylanase and Cellulase During Enzymatic Hydrolysis of Birch Wood

Understanding factors that affect the catalytic efficiency and synergism of enzymes is helpful to enhance the process of bioconversion. In this study, birch wood (BW) was sequentially treated by delignification (DL), deacetylation (DA), and decrystallization (DC) treatments. The physiochemical structures of treated BW were characterized. Moreover, the influences of sequential treatments on the catalytic efficiency and synergism of xylanase and cellulase were studied. DL treatments efficiently improved the conversion of cellulose and xylan. A high degree of synergy (DS) between xylanase and cellulase was produced during hydrolysis of DL-treated BW. DA treatments enhanced xylan conversion but reduced the DS between xylanase and cellulase for xylan hydrolysis, whereas DC treatments enhanced cellulose conversion but reduced the DS between xylanase and cellulase for cellulose hydrolysis. The cellulose conversion of lithium chloride/N,N-dimethylacetamide (LiCl/DMAc)-treated BW (89.69%) was higher than the cellulose conversion of ball milling (BM)-treated BW (81.63%), whereas the xylan conversion of LiCl/DMAc-treated BW (83.77%) was lower than the xylan conversion of BM-treated BW (87.21%). This study showed that the catalytic efficiency and synergism of xylanase and cellulase are markedly affected by lignin hindrance, hemicellulose acetylation, and cellulose crystallization.

Fizeau drag in graphene plasmonics

Dragging of light by moving media was predicted by Fresnel¹ and verified by Fizeau's celebrated experiments² with flowing water. This momentous discovery is among the experimental cornerstones of Einstein's special relativity theory and is well understood^3,4 in the context of relativistic kinematics. By contrast, experiments on dragging photons by an electron flow in solids are riddled with inconsistencies and have so far eluded agreement with the theory^5-7. Here we report on the electron flow dragging surface plasmon polaritons^8,9 (SPPs): hybrid quasiparticles of infrared photons and electrons in graphene. The drag is visualized directly through infrared nano-imaging of propagating plasmonic waves in the presence of a high-density current. The polaritons in graphene shorten their wavelength when propagating against the drifting carriers. Unlike the Fizeau effect for light, the SPP drag by electrical currents defies explanation by simple kinematics and is linked to the nonlinear electrodynamics of Dirac electrons in graphene. The observed plasmonic Fizeau drag enables breaking of time-reversal symmetry and reciprocity¹⁰ at infrared frequencies without resorting to magnetic fields^11,12 or chiral optical pumping^13,14. The Fizeau drag also provides a tool with which to study interactions and nonequilibrium effects in electron liquids.

Universality classes of the domain-wall creep motion driven by spin-transfer torques

With the stochastic Landau-Lifshitz-Gilbert equation, we numerically simulate the creep motion of a magnetic domain wall driven by the adiabatic and nonadiabatic spin-transfer torques induced by the electric current. The creep exponent μ and the roughness exponent ζ are accurately determined from the scaling behaviors. The creep motions driven by the adiabatic and nonadiabatic spin-transfer torques belong to different universality classes. The scaling relation between μ and ζ based on certain simplified assumptions is valid for the nonadiabatic spin-transfer torque, while invalid for the adiabatic one. Our results are compatible with the experimental ones, but go beyond the existing theoretical prediction. Our investigation reveals that the disorder-induced pinning effect on the domain-wall rotation alters the universality class of the creep motion.

Efficacy of Chinese Herbal Injections for Elderly Patients With pneumonia-A Bayesian Network Meta-analysis of Randomized Control Trials

Background: Pneumonia is a prevalent and complicated disease among adults, elderly people in particular, and the debate on the optimal Chinese herbal injections (CHIs) is ongoing. Our objective is to investigate the comparative effectiveness of various CHIs strategies for elderly patients with pneumonia. Methods: A comprehensive search strategy was executed to identify relevant randomized controlled trials (RCTs) by browsing through several databases from their inception to first, Feb 2020; All of the direct and indirect evidence included was rated by Network meta-analysis under a Bayesian framework. Results: We ultimately identified 34 eligible randomized controlled trials that involved 3,111 elderly participants and investigated 4 CHIs combined with Western medicine (WM) (Xiyanping injection [XYP]+WM, Yanhuning injection [YHN]+WM, Tanreqing injection [TRQ]+WM, Reduning injection [RDN]+WM), contributing 34 direct comparisons between CHIs. Seen from the outcome of Clinical effective rate and time for defervescence, patients taking medicine added with CHIs [Clinical effective rate, XYP + WM(Odd ratio (OR): 0.74, 95%Credible intervals (CrIs):0.55-0.98), YHN + WM(OR: 0.66, 95%CrI: 0.45-0.95), TRQ + WM(OR: 0.65, 95%CrI: 0.50-0.83), RDN + WM(OR: 0.60, 95%CrI: 0.40-0.89); Time for defervescence, YHN + WM(Mean difference (MD): -2.11, 95%CrI: -3.26 to -0.98), XYP + WM(MD: -2.06, 95%CrI: -3.08 to -1.09), RDN + WM(MD: -1.97, 95%CrI: -3.61 to -0.35), TRQ + WM(MD: -1.69, 95%CrI: -2.27 to -1.04)] showed statistically better effect compared with participants in the Control group (CG) who only took WM. Meanwhile, based on the time for disappearance of cough, 3 out of 4 CHIs [TRQ + WM(MD: -2.56, 95%CrI: -3.38 to -1.54), YHN + WM(MD: -2.36, 95%CrI: -3.86 to -1.00) and XYP + WM(MD: -2.21, 95%CrI: -3.72 to -1.10)] strategies indicated improvement of clinical symptoms. Only XYP + WM(MD -1.78, 95%CrI: -3.29 to -0.27) and TRQ + WM (MD: -1.71, 95%CrI: -2.71 to -0.73) could significantly shorten the time for disappearance of pulmonary rales. Conclusion: According to the statistical effect size (The surface under the cumulative ranking), we found that XYP + WM was presumably to be the preferable treatment for treating elderly patients with pneumonia compared with WM alone in terms of clinical effective rate. Our findings were based on very limited evidence and thus should be interpreted with caution. The application of the findings requires further research.

Enhanced ammonia sensing performance based on MXene-Ti3C2Tx multilayer nanoflakes functionalized by tungsten trioxide nanoparticles

Low-power consumption and high sensitivity are highly desirable for a vast range of NH₃ sensing applications. As a new type of two-dimension (2D) material, Ti₃C₂T_x is extensively studied for room temperature NH₃ sensors recently. However, the Ti₃C₂T_x MXene based gas sensors suffer mainly from low sensitivity. Herein, we report a sensitive Ti₃C₂T_x/WO₃ composite resistive sensor for NH₃ detection. The Ti₃C₂T_x/WO₃ composite consisting of WO₃ nanoparticles anchored on Ti₃C₂T_x nanoflakes were synthesized successfully with a facile ultra-sonication technique. The composite sensor with optimized components exhibits a high sensitivity of 22.3% for 1 ppm NH₃ at room temperature, which is 15.4 times higher than the pure Ti₃C₂T_x sensor. Furthermore, the composite sensor has excellent reproducibility, good long-term stability, and high selectivity to NH₃. The relative humidity influence on NH₃ gas sensing properties of the sensors was systematically studied. This research provides an efficient route for the preparation of novel MXene-based sensitive materials for high-performance NH₃ sensors.

Peak Width of Skeletonized Mean Diffusivity as Neuroimaging Biomarker in Cerebral Amyloid Angiopathy

BACKGROUND AND PURPOSE

Whole-brain network connectivity has been shown to be a useful biomarker of cerebral amyloid angiopathy and related cognitive impairment. We evaluated an automated DTI-based method, peak width of skeletonized mean diffusivity, in cerebral amyloid angiopathy, together with its association with conventional MRI markers and cognitive functions.

MATERIALS AND METHODS

We included 24 subjects (mean age, 74.7 [SD, 6.0] years) with probable cerebral amyloid angiopathy and mild cognitive impairment and 62 patients with MCI not attributable to cerebral amyloid angiopathy (non-cerebral amyloid angiopathy-mild cognitive impairment). We compared peak width of skeletonized mean diffusivity between subjects with cerebral amyloid angiopathy-mild cognitive impairment and non-cerebral amyloid angiopathy-mild cognitive impairment and explored its associations with cognitive functions and conventional markers of cerebral small-vessel disease, using linear regression models.

RESULTS

Subjects with Cerebral amyloid angiopathy-mild cognitive impairment showed increased peak width of skeletonized mean diffusivity in comparison to those with non-cerebral amyloid angiopathy-mild cognitive impairment (P < .001). Peak width of skeletonized mean diffusivity values were correlated with the volume of white matter hyperintensities in both groups. Higher peak width of skeletonized mean diffusivity was associated with worse performance in processing speed among patients with cerebral amyloid angiopathy, after adjusting for other MRI markers of cerebral small vessel disease. The peak width of skeletonized mean diffusivity did not correlate with cognitive functions among those with non-cerebral amyloid angiopathy-mild cognitive impairment.

CONCLUSIONS

Peak width of skeletonized mean diffusivity is altered in cerebral amyloid angiopathy and is associated with performance in processing speed. This DTI-based method may reflect the degree of white matter structural disruption in cerebral amyloid angiopathy and could be a useful biomarker for cognition in this population.

Clinical utility of expanded non-invasive prenatal screening and chromosomal microarray analysis in high-risk pregnancy

OBJECTIVE

To evaluate the utility of expanded non-invasive prenatal screening (NIPS), compared with chromosomal microarray analysis (CMA), for the detection of chromosomal abnormalities in high-risk pregnancies.

METHODS

This was a multicenter retrospective study of singleton pregnancies at high risk for chromosomal abnormality. Patients who underwent expanded NIPS and CMA sequentially during pregnancy from 2015 to 2019 were included in the analysis. Pregnancies with a positive result for sex chromosome aneuploidy were excluded as the full details could not be retrieved. The utility of expanded NIPS and CMA for detection of chromosomal abnormalities in this cohort was compared by assessing the concordance between the results.

RESULTS

Of the 774 included high-risk pregnancies, 550 (71.1%) had a positive NIPS result, while a positive CMA result was detected in 308 (39.8%) cases. The rate of full or partial concordance between NIPS and CMA was 82.2%, 59.6% and 25.0% for trisomies 21, 18 and 13, respectively. For rare aneuploidies and segmental imbalances, NIPS and CMA results were fully or partially concordant in 7.5% and 33.3% of cases, respectively. Copy-number variants < 5 Mb were detected more often by CMA, with an incidence of 7.9% (61/774) compared with 3.1% (24/774) by NIPS. A genetic aberration was detected by CMA in 1 in 17 (5.8%) high-risk pregnancies that had a negative or non-reportable NIPS result.

CONCLUSION

CMA allows for comprehensive detection of genome-wide chromosomal abnormalities in high-risk pregnancies. CMA should be offered instead of expanded NIPS for high-risk pregnancies. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Comparative study of lipid production from cellulosic ethanol fermentation wastewaters by four oleaginous yeasts

The biochemical treatment of cellulosic ethanol wastewater (CEW) is considered to be an ideal green process. To screen out the best oleaginous yeastfor the utilization of cellulosic ethanol wastewater, four oleaginous yeasts (Trichosporon cutaneum, Rhorosporidium toruloides, Cryptococcus albidus and T. coremiiforme) were compared to assess their abilities for lipid production in terms of biomass production, lipid content and lipid yield. Furthermore, thechemical oxygen demand (COD) conversion rate, COD degradation and fatty acid composition were calculated to analyze the effect of wastewaters treatment. According to the fermentation results, the highest biomass and lipid yield of T. cutaneum in CEW were 20.945 and 1.56 g/L, respectively, while the R. toruloides reached the highest lipid content (17.32%). The maximum conversion rates of T. cutaneum are 73.64 and 6.06%, respectively, in terms of conversion yield of biomass/COD and lipids/COD. The content of fatty acids showed that after six days' fermentation, T. coremiiforme obtained the highest unsaturated fatty acid content, the content of C18:1 and C18:2 was 57.64%. This study suggests that T. cutaneum has great potential for lipid production and wastewaters treatment from cellulosic ethanol fermentation.

Synthesis of polyacrylamide/polystyrene interpenetrating polymer networks and the effect of textural properties on adsorption performance of fermentation inhibitors from sugarcane bagasse hydrolysate

Economical removal of fermentation inhibitors from lignocellulosic hydrolysate plays a considerable role in bioconversion of lignocellulose biomass. In this work, the textural properties of polyacrylamide/polystyrene interpenetrating polymer networks (PAM/PS IPNs) on adsorption of fermentation inhibitors from sugarcane bagasse hydrolysate (SCBH) were investigated for the first time. The results showed that, the specific surface area, pore diameter and surface polarity had important influence on its adsorption performance towards sugars, organic acids, furans and acid-soluble lignin. The PAM/PS IPNs under the optimal copolymerization situation achieved the high selectivity coefficients of 4.07, 14.9, 21.2 and 25.8 with respective to levulinic acid, furfural, hydroxymethylfurfural (HMF) and acid-soluble lignin, and had a low total sugar loss of 2.09%. Overall, this research puts forward a design and synthetic strategy for adsorbent to remove fermentation inhibitors from lignocellulosic hydrolysate.

MicroRNA-1286 inhibits osteogenic differentiation of mesenchymal stem cells to promote the progression of osteoporosis via regulating FZD4 expression

OBJECTIVE

The aim of this study was to investigate whether microRNA-1286 could inhibit the osteogenic differentiation of human marrow mesenchymal stem cells (hMSCs) by regulating FZD4 expression and promoting the progression of osteoporosis.

PATIENTS AND METHODS

Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was used to detect the expression of microRNA-1286 in the serum of patients with osteoporosis. Meanwhile, microRNA-1286 expression in different stages of osteogenic differentiation of hMSCs was measured by qRT-PCR as well. After overexpression of microRNA-1286 and FZD4 in hMSCs, the mRNA expression levels of microRNA-1286, alkaline phosphatase (ALP), RUNX2 and osteocalcin (OCN) were detected by qRT-PCR. The protein expression levels of RUNX2 and OCN were detected by Western blot. Meanwhile, alkaline phosphatase (ALP) activity and expression in cells were examined using ALP assay kit and ALP staining method, respectively. Cell mineralized nodules were detected through the alizarin red staining test. Bioinformatics method was used to predict the binding site of microRNA-1286 to FZD4. Subsequent luciferase reporter gene assay was performed to verify whether microRNA-1286 could combine with FZD4. After overexpression or knockdown of microRNA-1286, the mRNA and protein expressions of FZD4 were analyzed using qRT-PCR and Western blot assay, respectively. After the simultaneous overexpression of microRNA-1286 and FZD4 in hMSCs, the mRNA expression levels of ALP, RUNX2 and OCN, ALP activity and content, and cell mineralization ability were successively examined.

RESULTS

The expression of microRNA-1286 in the serum of patients with osteoporosis was significantly higher than that of the normal population. Meanwhile, microRNA-1286 expression decreased with the increase of osteogenic differentiation days of hAMSCs. After the overexpression of microRNA-1286, ALP, RUNX2, and OCN levels, ALP activity, RUNX2, and OCN protein levels, as well as mineralized nodule formation were significantly reduced. However, results were reversed when FZD4 was simultaneously up-regulated. Luciferase reporter gene assay results verified that microRNA-1286 could bind to FZD4. After the overexpression of microRNA-1286, the mRNA and protein expressions of FZD4 were found significantly down-regulated. However, results were reversed after knocking down microRNA-1286. Furthermore, the simultaneous overexpression of microRNA-1286 and FZD4 could counteract the inhibitory effect of over-expression of microRNA-1286 on osteogenic differentiation of hMSCs.

CONCLUSIONS

MicroRNA-1286 can regulate FZD4 expression and inhibit osteogenic differentiation of hMSCs, thereby promoting the development of osteoporosis.

Coronavirus disease 2019: A new severe acute respiratory syndrome from Wuhan in China

An outbreak of new severe acute respiratory syndrome coronavirus disease, coronavirus disease 2019 (COVID-19), has emerged during December 2019. The ongoing outbreak in Wuhan City spread rapidly throughout China, where the fatality rate ranged from 2.1 to 4.9%. Due to its high transmissibility, the World Health Organization (WHO) declared a public health emergency of international concern on 30 January 2020. The current outbreak has the potential to become the first pandemic of the new millennium. Most patients who were first diagnosed with COVID-19 worked at or lived in the vicinity of the local Huanan Seafood Wholesale  Market, where live animals were also on sale. The concerted efforts of Chinese scientists led to the independent isolation from patients and identification of a novel coronavirus, SARS coronavirus 2 (SARS-CoV-2), on 6 January 2020; this has been an important step in the development of treatment. The purpose of this article is to overview the history, epidemiology, clinical characteristics, diagnosis, and treatment of COVID 2019 reported in recently published studies. Based on the results of virus genome sequencing and a model of the interaction between host cells and the virus, we propose several possible targets for antiviral drugs, which may provide new ideas for epidemic control and vaccine development. Keywords: 2019 novel coronavirus; pneumonia; SARS-CoV-2; Coronaviridae; COVID-19.

Production, separation, and characterization of high-purity xylobiose from enzymatic hydrolysis of alkaline oxidation pretreated sugarcane bagasse

The production of high-purity xylobiose from lignocellulose is an expensive and tedious process. In this work, the production of xylobiose from enzymatic hydrolysis of alkaline oxidation pretreated sugarcane bagasse was investigated. Furthermore, a simple process for the separation of xylobiose from enzymatic hydrolysate by activated carbon absorption, water washing, and ethanol-water desorption was developed. Under the optimized separation conditions, 96.77% xylobiose was adsorbed at 16% activated carbon loadings. Moreover, xylose and acetate could not be detected after washing by 3-fold volume of water. Xylobiose with 80.16% yield was eluted by 5-fold volume of 5% (v/v) ethanol-water. The reusability of activated carbon was evaluated by 5 cycles of adsorption-desorption process, suggesting that the activated carbon exhibited good reusability. The separated xylobiose sample with high-purity (97.29%) was confirmed by HPLC, ESI-MS, and NMR. Overall, this study provided a low-cost and robust technology for the production and separation of high-purity xylobiose from lignocellulose.

The Application of Non-linear Flow Resistance in Cerebral Artery: Compared with Windkessel Model based on Genetic Algorithm

Continuous blood pressure is measured from various extracranial body sites, with difference in amplitude and phase with intracranial blood pressure. Consequent influences on the accuracy of Windkessel model need further investigation. Between blood pressure and intracranial flow rate, a model with non-linear flow resistance (R-DT) was proposed and compared with the 3-element Windkessel (RCR) model. From the measured blood flow velocity in middle cerebral artery, the blood pressure was estimated by R-DT and RCR models respectively. The parameters in the models were optimized by genetic algorithm. The accuracies of R-DT and RCR models were compared based on their estimation errors to the measured blood pressure. The capacitance element in RCR model indicated limited ability to take the time shift into account. Compared with RCR model, R-DT model had less error (averaged relative error: 5.19% and 2.49% for RCR and RDT models). The non-linear flow resistance was applicable in simulating cerebral arteries.

MiR-93 blocks STAT3 to alleviate hepatic injury after ischemia-reperfusion

OBJECTIVE

Signal transducer and activator of transcription 3 (STAT3) is correlated with ischemia-reperfusion (I-R) injury. The previous studies showed a decreased miR-93 expression after I-R injury of heart or brain organs, but without knowledge in liver tissues. This study aims to investigate effects of MiR-93 on the hepatic injury after ischemia/reperfusion.

MATERIALS AND METHODS

Rat liver I-R model was generated. Liver function indexes including alanine transaminase (ALT) and aspartate aminotransferase (AST) were quantified, and serum tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) levels were quantified. Hepatic tissue apoptosis was measured by transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL), and expression of microRNA-93 (miR-93), STAT3, and phosphorylated STAT3 (p-STAT3) were measured. Dual luciferase reporter gene assay confirmed targeted relationship between miR-93 and STAT3. Agomir or miR-93 agomir was injected into the peritoneal cavity of I-R model, followed by ALT and AST assays. Serum levels of TNF-α, IL-1β, and IL-6 were measured, followed by TUNEL assay for comparing STAT3 and p-STAT3 expression.

RESULTS

Comparing to sham group, I-R group rat showed significantly elevated serum ALT, AST, TNF-α, IL-1β, and IL-6 contents, along with significantly elevated hepatic cell apoptosis, plus decreased miR-93 expression, whilst STAT3 and p-STAT3 expression was enhanced. Intraperitoneal injection of miR-93 agomir significantly decreased STAT3 or p-STAT3 expression, and decreased cell apoptotic rate. Serum levels of ALT, AST, TNF-α, IL-1β, and IL-6 were significantly decreased, accompanied by improved liver function.

CONCLUSIONS

Hepatic I-R injury is accompanied by miR-93 down-regulation, plus STAT3 up-regulation. Overexpression of miR-93 significantly depressed STAT3 expression in liver I-R injury, alleviated hepatic injury or apoptosis, decreased inflammatory response, and improved liver function.

Photonic crystal for graphene plasmons

Photonic crystals are commonly implemented in media with periodically varying optical properties. Photonic crystals enable exquisite control of light propagation in integrated optical circuits, and also emulate advanced physical concepts. However, common photonic crystals are unfit for in-operando on/off controls. We overcome this limitation and demonstrate a broadly tunable two-dimensional photonic crystal for surface plasmon polaritons. Our platform consists of a continuous graphene monolayer integrated in a back-gated platform with nano-structured gate insulators. Infrared nano-imaging reveals the formation of a photonic bandgap and strong modulation of the local plasmonic density of states that can be turned on/off or gradually tuned by the applied gate voltage. We also implement an artificial domain wall which supports highly confined one-dimensional plasmonic modes. Our electrostatically-tunable photonic crystals are derived from standard metal oxide semiconductor field effect transistor technology and pave a way for practical on-chip light manipulation.

Traditional photonic crystals consist of periodic media with a pre-defined optical response. Here, the authors combine nanostructured back-gate insulators with a continuous layer of graphene to demonstrate an electrically tunable two-dimensional photonic crystal suitable for controlling the propagation of surface plasmon polaritons.

Anaerobic digestion of elephant grass hydrolysate: Biogas production, substrate metabolism and outlet effluent treatment

Elephant grass (Pennisetum purpureum) acid hydrolysate was used as substrate for anaerobic digestion for the first time. Within short period (ten days), the organic materials (sugars and organic acids) in the elephant grass hydrolysate could be utilized efficiently for stable biogas production that the COD removal, biogas yield, and CH₄ content were 91.3 ± 2.0%, 0.561 ± 0.014 m³/kg _COD consumption, and 68.1 ± 4.6%, respectively throughout this bioprocess. During anaerobic digestion, almost no volatile fatty acids (VFAs) was accumulated (merely <0.1 g/L acetic acid was found) and the outlet pH was very stable (7.3 ± 0.1). Meanwhile, the furans including furfural and 5-hydroxymethylfurfural (HMF) existing in the inlet substrate could be degraded. After anaerobic digestion, the outlet effluent was treated by combination of Fe-C micro-electrolysis and Fenton reaction to remove 93.1% of residual COD and 98.6% of color. Considering the performance, cost, operation, and environmental influence, this technology is suitable for industrial treatment of waste elephant grass.

Introduction of one efficient industrial system for turpentine processing wastewater reuse and treatment

Wastewater treatment is one important issue for turpentine plant and more wastewater generated by greater turpentine processing will prevent its further development. To solve this issue without extra place and new equipment, one industrial system for reuse and treatment of turpentine processing wastewater was introduced for the first time. For wastewater reuse, the technology was simple and easy to control that after neutralization by lime and absorption with activated carbon (optional, mostly not necessary), the wastewater could be reused for turpentine processing. After reuse, the wastewater was further treated by a biological system. During long-term application of wastewater reuse in this plant, it showed little influence on the products performance (mainly acid value) and final wastewater COD. Base on above advantages, the plant could decide when for wastewater drainage, and thus the amount of wastewater was reduced greatly. For the biological treatment, the COD of wastewater could be degraded to suitable level stably and the wastewater after treatment could be applied for daily life in the plant. Overall, considering the cost, operation, and performance, the whole system shows great potential and possibility of industrial application and therefore can be applied widely in the turpentine processing industry.

Determining intracellular lipid content of different oleaginous yeasts by one simple and accurate Nile Red fluorescent method

A simple and accurate Nile Red fluorescent method was built to evaluate the lipid content of three different oleaginous yeasts by one standard curve. The staining of cells can be observed clearly by laser scanning confocal microscope, showing that Nile Red can enter into the cells of oleaginous yeasts easily. A series of conditions such as pretreating temperature, cell suspension concentration (OD₆₀₀), staining time, Nile Red concentration and the type of suspension solvent were learnt systematically to obtain the optimal process parameters for Nile Red staining. After optimization, the fitting curve of Nile Red fluorescent method was established under suitable conditions (pretreating temperature: 50 °C, OD₆₀₀: 1.0; staining time: 5 mins; Nile Red concentration: 1.0 μg/mL; suspension solvent: PBS) and it had a suitable correlation coefficient (R² = 0.95) for lipid content measurement of different oleaginous yeasts. By this study, the possibility of lipid content determination of different oleaginous yeasts by one fitting curve can be proven and this will improve the efficiency of researches related to microbial lipid production.