Prognostic Utility of Cardiac MRI Myocardial Strain Parameters in Patients With Ischemic and Nonischemic Dilated Cardiomyopathy: A Multicenter Study.

BACKGROUND. Prior small single-center studies have yielded conflicting results regarding the prognostic significance of myocardial strain parameters derived from feature tracking (FT) on cardiac MRI in patients with dilated cardiomyopathy (DCM). OBJECTIVE. The purpose of this study was to evaluate the prognostic utility of FT parameters on cardiac MRI in patients with ischemic and nonischemic DCM and to determine the optimal strain parameter for outcome prediction. METHODS. This retrospective study included 471 patients (median age, 61 years; 365 men, 106 women) with ischemic (n = 233) or nonischemic (n = 238) DCM and left ventricular (LV) ejection fraction (EF) less than 50% who underwent cardiac MRI at any of four centers from January 2011 to December 2019. Cardiac MRI parameters were determined by manual contouring. In addition, software-based FT was used to calculate six myocardial strain parameters (LV and right ventricular [RV] global radial strain, global circumferential strain, and global longitudinal strain [GLS]). Late gadolinium enhancement (LGE) was also evaluated. Patients were assessed for a composite outcome of all-cause mortality and/or heart-failure hospitalization. Cox regression models were used to determine associations between strain parameters and the composite outcome. RESULTS. Mean LV EF was 27.5% and mean LV GLS was -6.9%. The median follow-up period was 1328 days. The composite outcome occurred in 220 patients (125 deaths, 95 heart-failure hospitalizations). All six myocardial strain parameters were significant independent predictors of the composite outcome (hazard ratio [HR] = 0.92-1.16; all p < .05). In multivariable models that included age, corrected LV and RV end-diastolic volume, LV and RV EF, and presence of LGE, the only strain parameter that was a significant independent predictor of the composite outcome was LV GLS (HR = 1.13, p = .006); LV EF and presence of LGE were not independent predictors of the composite outcome in the models (p > .05). A LV GLS threshold of -6.8% had sensitivity of 62.6% and specificity of 62.6% in predicting the composite outcome rate at 4.0 years. CONCLUSION. LV GLS, derived from FT on cardiac MRI, is a significant independent predictor of adverse outcomes in patients with DCM. CLINICAL IMPACT. This study strengthens the body of evidence supporting the clinical implementation of FT when performing cardiac MRI in patients with DCM.

CT differential diagnosis of COVID-19 and non-COVID-19 in symptomatic suspects: a practical scoring method.

BACKGROUND: Although typical and atypical CT image findings of COVID-19 are reported in current studies, the CT image features of COVID-19 overlap with those of viral pneumonia and other respiratory diseases. Hence, it is difficult to make an exclusive diagnosis. METHODS: Thirty confirmed cases of COVID-19 and forty-three cases of other aetiology or clinically confirmed non-COVID-19 in a general hospital were included. The clinical data including age, sex, exposure history, laboratory parameters and aetiological diagnosis of all patients were collected. Seven positive signs (posterior part/lower lobe predilection, bilateral involvement, rounded GGO, subpleural bandlike GGO, crazy-paving pattern, peripheral distribution, and GGO +/- consolidation) from significant COVID-19 CT image features and four negative signs (only one lobe involvement, only central distribution, tree-in-bud sign, and bronchial wall thickening) from other non-COVID-19 pneumonia were used. The scoring analysis of CT features was compared between the two groups (COVID-19 and non-COVID-19). RESULTS: Older age, symptoms of diarrhoea, exposure history related to Wuhan, and a lower white blood cell and lymphocyte count were significantly suggestive of COVID-19 rather than non-COVID-19 (p < 0.05). The receiver operating characteristic (ROC) curve of the combined CT image features analysis revealed that the area under the curve (AUC) of the scoring system was 0.854. These cut-off values yielded a sensitivity of 56.67% and a specificity of 95.35% for a score > 4, a sensitivity of 100% and a specificity of 23.26% for a score > 0, and a sensitivity of 86.67% and a specificity of 67.44% for a score >  2. CONCLUSIONS: With a simple and practical scoring system based on CT imaging features, we can make a hierarchical diagnosis of COVID-19 and non-COVID-19 with different management suggestions.

Isolation and Characterization of a Novel Cold-Active, Halotolerant Endoxylanase from Echinicola rosea sp. Nov. JL3085T.

We cloned a xylanase gene (xynT) from marine bacterium Echinicola rosea sp. nov. JL3085T and recombinantly expressed it in Escherichia coli BL21. This gene encoded a polypeptide with 379 amino acid residues and a molecular weight of ~43 kDa. Its amino acid sequence shared 45.3% similarity with an endoxylanase from Cellvibrio mixtus that belongs to glycoside hydrolases family 10 (GH10). The XynT showed maximum activity at 40 °C and pH 7.0, and a maximum velocity of 62 µmoL min-1 mg-1. The XynT retained its maximum activity by more than 69%, 51%, and 26% at 10 °C, 5 °C, and 0 °C, respectively. It also exhibited the highest activity of 135% in the presence of 4 M NaCl and retained 76% of its activity after 24 h incubation with 4 M NaCl. This novel xylanase, XynT, is a cold-active and halotolerant enzyme that may have promising applications in drug, food, feed, and bioremediation industries.

Dynamic growth models for Caragana korshinskii shrub biomass in China.

The Caragana korshinskii shrub is a widely distributed plant found in arid regions and plays an important role in ecological environment protection. Accurate estimations of shrub biomass are particularly important for natural resource management decision making. 114 individual C. korshinskii shrubs from three regions were collected in northwest China in this study. With regions as fixed (dummy variables) and random effects, the nonlinear least square (NLS) regression approach, nonlinear fixed effects (NLFE) approach and nonlinear mixed effects (NLME) approach were developed to predict dynamic growth of total, aboveground, stem, foliage, and root biomass values of C. korshinskii shrub based on logistic function. Results revealed that both NLFE and NLME models performed better than NLS, which indicated that regions were important factors influenced shrub biomass dynamic growth. Additionally, NLME models had a smaller Bayesian information criterion (BIC) than NLFE models. For NLME models, the random effects of regions mainly influenced the growth rate and asymptotic value of the dynamic growth curve, and there was no significant influence on the values associated with the curve shape. Moreover, the modified NLME models with heteroscedasticity exhibited extremely significant differences (p < 0.0001) when compared to NLME models by the likelihood ratio (LR) test. The NLME models were proved to be an efficient approach for considering the random effects on shrub biomass dynamic growth and accounted for the heteroscedasticity of shrub biomass data.

Effect of Hydroxyapatite Nanorods on the Fate of Human Adipose-Derived Stem Cells Assessed In Situ at the Single Cell Level with a High-Throughput, Real-Time Microfluidic Chip.

The fate of stem cells at the single cell level with limited communication with other cells is still unknown due to the lack of an efficient tool for highly accurate molecular detection. Moreover, the conditional sensitivity of biological experiments requires a sufficient number of parallel experiments to support a conclusion. In this work, a microfluidic single cell chip is designed for use with a protein chip to investigate the effect of hydroxyapatite (HAp) on the osteogenic differentiation of human adipose-derived stem cells (hADSCs) in situ at the single cell level. By successfully detecting secretory proteins in situ, it is found that the HAp nanorods enhance osteogenic differentiation at the single cell level. In the chip, the single cell seeding approach confirms the osteogenic differentiation of the hADSCs, which endocytoses HAp, by reducing the influence of the factors secreted by neighboring differentiating cells. Most importantly, more than 7000 microchambers provide a sufficient number of parallel experiments for statistical analysis, which ensure a high level of repeatability of the HAp nanorod-induced osteogenic differentiation. The microfluidic chip comprising single cell culture microchambers with in situ detection capability is a promising tool for research on cell behavior or cell fate at the single cell level.

Third-generation D-lactic acid production using red macroalgae Gelidium amansii by co-fermentation of galactose, glucose and xylose.

Macroalgae biomass has been considered as a promising renewable feedstock for lactic acid production owing to its lignin-free, high carbohydrate content and high productivity. Herein, the D-lactic acid production from red macroalgae Gelidium amansii by Pediococcus acidilactici was investigated. The fermentable sugars in G. amansii acid-prehydrolysate were mainly galactose and glucose with a small amounts of xylose. P. acidilactici could simultaneously ferment the mixed sugars of galactose, glucose and xylose into D-lactic acid at high yield (0.90 g/g), without carbon catabolite repression (CCR). The assimilating pathways of these sugars in P. acidilactici were proposed based on the whole genome sequences. Simultaneous saccharification and co-fermentation (SSCF) of the pretreated and biodetoxified G. amansii was also conducted, a record high of D-lactic acid (41.4 g/L) from macroalgae biomass with the yield of 0.34 g/g dry feedstock was achieved. This study provided an important biorefinery strain for D-lactic acid production from macroalgae biomass.

Efficiency and ecological safety of herbicide haloxyfop-R-methyl on removal of coastal invasive plant Spartina alterniflora.

Spartina alterniflora is a global invasive plant and has caused considerable damage to coastal wetland ecosystem. This study evaluated the efficiency and ecological safety of herbicide haloxyfop-R-methyl (HPME) in removing S alterniflora in Laizhou Bay. The results showed that the density of regenerated S. alterniflora after 10 months of application of 0.01, 0.02 and 0.03 g/m2 HPME decreased by 86.67 %, 99.16 % and 99.31 %, respectively. Moreover, seed abortion rates were 62.25 %, 92.24 % and 94.82 %, and weight of roots in HPME groups were 56.63 %, 59.99 %, and 40.10 % of those in the control group. After 4 days of application, HPME could not be detected in S. alterniflora and sediments. In addition, HPME did not change sediment physicochemical properties, macrozoobenthos community and microbial community structure during 16 days, but increased the density of native macrozoobenthos after 1 year. Therefore, HPME might be an effective and ecologically safe chemical for the eradication of S. alterniflora.

Co-expression of Xylose Transporter and Fructose-Bisphosphate Aldolase Enhances the Utilization of Xylose by Lactococcus lactis IO-1.

The raw material cost of lactic acid fermentation accounts for the main part of the production cost, and this necessitates the exploration of the efficient use of cheap raw materials in lactic acid production. We compared the outcomes of the homologous expressions of xylose transporters (xylFGH, xylE, araE, and xylT), 6-phosphofructokinase (pfkA), fructose-bisphosphate aldolase (fbaA), and their co-expression in Lactococcus lactis IO-1 on lactic acid production using xylose as the raw material. We found that the production rate of lactic acid on xylose fermentation by L. lactis IO-1 overexpressing fbaA was the highest (14.42%). Among the xylose transporters investigated, XylT had the strongest xylose transport capacity in L. lactis IO-1, with an increase in the lactic acid production rate by 10.38%. The genes near the overexpression of fbaA or xylT in the metabolic pathway were more upregulated than the distant genes. The co-expression of fbaA and xylT increased the production rate of lactic acid by 27.84% on xylose fermentation by L. lactis IO-1. This work presents a novel strategy for the simultaneous enhancement of the expression of important genes at the beginning and midway of the xylose metabolic pathway of L. lactis IO-1, which could greatly improve the target production.

Enhanced cellulosic d-lactic acid production from sugarcane bagasse by pre-fermentation of water-soluble carbohydrates before acid pretreatment.

After several rounds of milling process for sugars extraction from sugarcane, certain amounts of water-soluble carbohydrates (WSC) still remain in sugarcane bagasse. It is a bottleneck to utilize WSC in sugarcane bagasse biorefinery, since these sugars are easily degraded into inhibitors during pretreatment. Herein, a simple pre-fermentation step before pretreatment was conducted, and 98 % of WSC in bagasse was fermented into d-lactic acid. The obtained d-lactic acid was stably preserved in bagasse and 5-hydroxymethylfurfural (HMF) generation was sharply reduced from 46.0 mg/g to 6.2 mg/g of dry bagasse, after dilute acid pretreatment. Consequently, a higher d-lactic acid titer (57.0 g/L vs 33.2 g/L) was achieved from the whole slurry of the undetoxified and pretreated sugarcane bagasse by one-pot simultaneous saccharification and co-fermentation (SSCF), with the overall yield of 0.58 g/g dry bagasse. This study gave an efficient strategy for enhancing lactic acid production using the lignocellulosic waste from sugar industry.

Acquired tolerance to oxidative stress in Bifidobacterium longum 105-A via expression of a catalase gene.

For improvement of tolerance to oxidative stress in Bifidobacterium longum 105-A, we introduced the Bacillus subtilis catalase gene (katE) into it. The transformant showed catalase activity (39 U/mg crude protein) in the intracellular fraction, which increased survival by ∼100-fold after a 1-h exposure to 4.4 mM H(2)O(2), decreased de novo H(2)O(2) accumulation, and increased survival in aerated cultures by 10(5)-fold at 24 h. The protection level was better than that conferred by exogenously added catalase.

A targeted gene knockout method using a newly constructed temperature-sensitive plasmid mediated homologous recombination in Bifidobacterium longum.

Bifidobacteria are the main component of the human microflora. We constructed a temperature-sensitive (Ts) plasmid by random mutagenesis of the Bifidobacterium-Escherichia coli shuttle vector pKKT427 using error-prone PCR. Mutant plasmids were introduced into Bifidobacterium longum 105-A and, after screening approximately 3,000 colonies, candidate clones that grew at 30 °C but not at 42 °C were selected. According to DNA sequence analysis of the Ts plasmid, five silent and one missense mutations were found in the repB region. The site-directed mutagenesis showed only the missense mutation to be relevant to the Ts phenotype. We designated this plasmid pKO403. The Ts phenotype was also observed in B. longum NCC2705 and Bifidobacterium adolescentis ATCC15703. Single-crossover homologous-recombination experiments were carried out to determine the relationship between the length of homologous sequences encoded on the plasmid and recombination frequency: fragments greater than 1 kb gave an efficiency of more than 10(3) integrations per cell. We performed gene knockout experiments using this Ts plasmid. We obtained gene knockout mutants of the pyrE region of B. longum 105-A, and determined that double-crossover homologous recombination occurred at an efficiency of 1.8 %. This knockout method also worked for the BL0033 gene in B. longum NCC2705.

Eelgrass (Zostera marina) and its epiphytic bacteria facilitate the sinking of microplastics in the seawater.

Marine microplastics have received considerable attention as a global environmental issue. However, despite the constant accumulation of microplastics in the ocean, their transport processes and mechanisms remain poorly understood. This study investigated microplastics in the sediments of seagrass meadows and nearby regions without seagrass along the Shandong coast and found that the sediment in the seagrass meadows was a sink for microplastics. Subsequently, we evaluated the influence of eelgrass (Zostera marina), a common coastal seagrass, on the sedimentation of suspended polystyrene microplastics. The results showed that 0.5, 1.0, and 2.0 g/L eelgrass leaves decreased the abundance of microplastics in seawater in a dose-dependent manner over a period of 3-48 h under shaking conditions at 120 rpm at 22 °C. After 48 h of shaking, microplastic abundances in the 0.5, 1.0, and 2.0 g/L eelgrass groups significantly decreased by 46.9%, 53.1%, and 88.4%, respectively. Microplastics can adhere to eelgrass leaves and form biofilms, which promoted the formation of white floc that traps the suspended microplastics, causing them to sink. Furthermore, two epiphytic bacteria (Vibrio and Exiguobacterium) isolated from the eelgrass leaves decreased the abundances of suspended microplastics by 95.7% and 94.5%, respectively, in 48 h by accelerating the formation of biofilms on the microplastics. Therefore, eelgrass and its epiphytic bacteria facilitated the sinking of microplastics and increased the accumulation of microplastics in the sediments of seagrass meadows in coastal regions.

One-pot fermentation for erythritol production from distillers grains by the co-cultivation of Yarrowia lipolytica and Trichoderma reesei.

A co-fermentation process involving Yarrowia lipolytica and Trichoderma reesei was studied, using distillers grains (DGS) as feedstocks for erythritol production. DGS can be effectively hydrolyzed by cellulase in the single-strain culture of T. reesei. One-pot solid state fermentation for erythritol production was then established by co-cultivating Y. lipolytica M53-S with the 12 h delay inoculated T. reesei Rut C-30, in which efficient saccharification of DGS and improved production of erythritol were simultaneously achieved. The 10:1 inoculation proportion of Y. lipolytica and T. reesei contributed to the maximum erythritol production of 267.1 mg/gds under the optimal conditions including initial moisture of 55%, pH of 5.0, NaCl addition of 0.02 g/gds and DGS mass of 200 g in 144 h co-cultivation. Being compared with the attempts to produce erythritol from other raw materials, the one-pot SSF with DGS is proposed to be a potential strategy for efficient and economical erythritol production.

One-pot d-lactic acid production using undetoxified acid-pretreated corncob slurry by an adapted Pediococcus acidilactici.

Inhibitor tolerance is still a bottleneck for lactic acid bacteria in lignocellulose biorefinery, while it is hard to obtain one engineered strain with strong tolerance to all inhibitors. Herein, a robust adapted d-lactic acid producing strain Pediococcus acidilactici XH11 was obtained by 111 days' long-term adaptive evolution in undetoxified corncob prehydrolysates. The adapted strain had higher inhibitors tolerance compared to the parental strain, primarily due to its increased conversion capacities of four typical aldehyde inhibitors (furfural, HMF, vanillin, and 4-hydroxybenzaldehyde). One-pot simultaneous saccharification and co-fermentation was successfully achieved using the whole slurry of acid-pretreated corncob without solid-liquid separation and detoxification, by applying the adapted P. acidilactici XH11. Finally, 61.9 g/L of d-lactic acid was generated after 96 h' fermentation (xylose conversion of 89.9 %) with the overall yield of 0.48 g/g dry corncob. This study gave an important option for screening of industrial strains in cellulosic lactic acid production processes.

Alterations in whole-brain dynamic functional stability during memory tasks under dexmedetomidine sedation.

Purpose: This study aimed to explore the neurological effects of dexmedetomidine-induced sedation on memory using functional stability, a whole-brain voxel-wise dynamic functional connectivity approach. Methods: A total of 16 participants (10 men) underwent auditory memory task-related fMRI in the awake state and under dexmedetomidine sedation. Explicit and implicit memory tests were conducted 4 h after ceasing dexmedetomidine administration. One-sample Wilcoxon signed rank test was applied to determine the formation of explicit and implicit memory in the two states. Functional stability was calculated and compared voxel-wise between the awake and sedated states. The association between functional stability and memory performance was also assessed. Results: In the awake baseline tests, explicit and implicit memory scores were significantly different from zero (p < 0.05). In the tests under sedation, explicit and implicit memory scores were not significantly different from zero. Compared to that at wakeful baseline, functional stability during light sedation was reduced in the medial prefrontal cortex, left angular gyrus, and right hippocampus (all clusters, p < 0.05, GRF-corrected), whereas the left superior temporal gyrus exhibited higher functional stability (cluster p < 0.05, GRF-corrected). No significant associations were observed between functional stability and memory test scores. Conclusions: The distribution and patterns of alterations in functional stability during sedation illustrate the modulation of functional architecture by dexmedetomidine from a dynamic perspective. Our findings provide novel insight into the dynamic brain functional networks underlying consciousness and memory in humans.

[Characteristics and composition of vegetation carbon storage in natural grassland in Ning-xia, China.] / 宁夏天然草地植被碳储量特征及构成.

We measured the total vegetation carbon stock in the widely distributed natural grassland of meadow steppe (MS), warm steppe (WS), steppe desert (SD) and desert steppe (DS)] in Ningxia, using survey and sampling method. The results showed that the average carbon rate of vege-tation, shrubs and root were 0.40, and that of litter was 0.39. The total vegetation carbon density of meadow steppe, warm steppe, steppe desert and desert steppe (including aboveground vegetation, litter and roots) was 470.26, 192.23, 117.17 and 83.36 g·m-2, while that of aboveground vegetation was 87.35, 68.50, 59.32 and 40.05 g·m-2, and that of roots was 344.29, 108.83, 50.65 and 30.29 g·m-2, litter carbon storage was 38.62,14.91, 7.19 and 13.03 g·m-2, respectively. The order of those grassland types ranked as MS＞WS＞SD＞DS. Root carbon storage contributed the most to carbon storage in meadow steppe and warm steppe, and aboveground vegetation carbon storage contributed the most to steppe desert and desert steppe. Root carbon storage showed a decreasing trend with the increases of soil depth within 40 cm soil layer. For the spatial distribution of total carbon stock, the southern part of meadow steppe and temperate steppe had obviously higher carbon stock than the middle and north part of desert steppe and steppe desert.

Direct conversion of cheese whey to polymalic acid by mixed culture of Aureobasidium pullulans and permeabilized Kluyveromyces marxianus.

Cheese whey is an abundant and low-cost feedstock with lactose as its main component, but the inability to metabolize lactose prevents Aureobasidium pullulans from using cheese whey directly. In this study, Kluyveromyces marxianus was permeabilized to obtain nonviable but biocatalytic cells for lactose hydrolysis, and the mixed culture of A. pullulans and permeabilized K. marxianus was conducted for polymalic acid (PMA) production from cheese whey. In the mixed culture, PMA titer varied directly to ß-galactosidase activity of K. marxianus, but inversely to cell viability of K. marxianus, and ethanol permeabilized K. marxianus was the most compatible with A. pullulans for PMA production. 37.8 g/L PMA was produced in batch fermentation, and PMA titer was increased to 97.3 g/L in fed-batch fermentation, with a productivity of 0.51 g/(L·h) and a yield of 0.56 g/g. This study paved an economical and environmentally friendly way for PMA production from cheese whey.

Hydroxyapatite Nanorods Function as Safe and Effective Growth Factors Regulating Neural Differentiation and Neuron Development.

Neural stem cell (NSC) transplantation is one of the most promising therapeutic strategies for neurodegenerative diseases. However, the slow spontaneous differentiation of NSCs often hampers their application in neural repair. Although some biological growth factors accelerate the differentiation of NSCs, their high cost, short half-life, and unpredictable behavior in vivo, as well as the complexity of the operation, hinder their clinical use. In this study, it is demonstrated that hydroxyapatite (HAp), the main component of bone, in the form of nanorods, can regulate the neural differentiation of NSCs and maturation of the newly differentiated cells. Culturing NSCs with HAp nanorods leads to the differentiation of NSCs into mature neurons that exhibit well-defined electrophysiological behavior within 5 days. The state of these neurons is much better than when culturing the cells without HAp nanorods, which undergo a 2-week differentiation process. Furthermore, RNA-sequencing data reveal that the neuroactive ligand-receptor interaction pathway is dominant in the enriched differentiated neuronal population. Hence, inorganic growth factors like HAp act as a feasible, effective, safe, and practical tool for regulating the differentiation of NSCs and can potentially be used in the treatment of neurodegenerative diseases.

[Carbon sequestration characteristics of typical temperate natural grasslands in Ningxia, China]. / å®å¤å ¸åž‹æ¸©æ€§å¤©ç„¶è‰åœ°å›ºç¢³ç‰¹å¾.

To accurately estimate ecosystem carbon storage of natural grassland in Ningxia, we examined ecosystem carbon storage in four types of typical temperate natural grasslands, including meadow steppe, warm steppe, steppe desert, and desert steppe in Ningxia. The results showed that the total vegetation biomass of meadow steppe, warm steppe, steppe desert and desert steppe were 1178.91, 481.22, 292.80 and 209.09 g·m-2, respectively. Root biomass was the main component of total vegetation biomass of meadow steppe and warm steppe, with a contribution of 73.1% and 56.6%, respectively. Aboveground biomass was the main component of total vegetation biomass of steppe desert and desert steppe, accounting for 50.3% and 47.6%, respectively. Litter made low contribution, being 8.5%, 8.0%, 6.4% and 16.2%, respectively. Ecosystem carbon storage of four typical natural grassland was 13.90, 5.94, 2.69 and 2.37 kg·m-2, vegetation carbon storage was 470.26, 192.23, 117.17 and 83.36 g·m-2, and soil organic carbon storage in 0-40 cm layers were 13.43, 5.75, 2.58 and 2.29 kg·m-2, respectively. Soil organic carbon storage was the main body of the total carbon storage of four typical natural grassland in Ningxia, accounting for 96.6%, 96.8%, 95.6% and 96.5%, respectively. The total vegetation biomass, vegetation carbon storage, soil organic carbon storage and ecosystem carbon storage of four natural grassland types were in the order of meadow steppe＞warm steppe＞steppe desert＞desert steppe.