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Alginate is a natural polysaccharide resource abundant in brown algae and it can be cleaved into alginate oligosaccharides by alginate lyase. Alginate lyases and the bioactive alginate oligosaccharides have been applied in diverse fields such as pharmaceutical therapy and nutraceutical supplementation. Immobilized enzymes greatly facilitate their industrial application owing to their reusability, stability, and tunability. In this study, magnetic Fe3O4 nanoparticles were synthesized and used to immobilize an exolytic alginate lyase AlgL17 that was characterized previously. The immobilized AlgL17 demonstrated enhanced thermal and pH tolerance, extended storage stability, and moderate reusability. The mass spectrum indicated the specific activity of the immobilized AlgL17 to release alginate oligosaccharides (AOS) from alginate polysaccharide. The produced AOS exhibited their antioxidant and antiapoptotic activities in H2O2-stressed human umbilical vein endothelial cells by upregulation of reactive oxygen species scavenging activities and attenuation of the caspase-mediated apoptosis pathway.

During a survey of plant parasitic nematodes in 2019, at Gansu Province, China, the stunt nematode Tylenchorhynchus zeae was found parasitizing corn seedlings. Females, males and juveniles of T. zeae were observed on soil and roots samples of corn after processing and extraction. This population of stunt nematodes was identified based on morphological and by sequencing the ITS1 region of rDNA and D2/D3 fragments of the 28 S rRNA. The ITS1 and the D2/D3 sequences of this population, shared 99.00 to 99.05% and 99.43 to 99.73% of similarity with sequences corresponding to T. zeae in GenBank, respectively. This is the first report of T. zeae infecting corn in Gansu Province, northwest China. During a survey of plant parasitic nematodes in 2019, at Gansu Province, China, the stunt nematode Tylenchorhynchus zeae was found parasitizing corn seedlings. Females, males and juveniles of T. zeae were observed on soil and roots samples of corn after processing and extraction. This population of stunt nematodes was identified based on morphological and by sequencing the ITS1 region of rDNA and D2/D3 fragments of the 28 S rRNA. The ITS1 and the D2/D3 sequences of this population, shared 99.00 to 99.05% and 99.43 to 99.73% of similarity with sequences corresponding to T. zeae in GenBank, respectively. This is the first report of T. zeae infecting corn in Gansu Province, northwest China.

Background Oral squamous cell carcinoma (OSCC) is a major lethal malignant cancer of the head and neck region, yet its molecular mechanisms of tumourigenesis are still unclear. Patients and methods We performed weighted gene co-expression network analysis (WGCNA) on RNA-sequencing data with clinical information obtained from The Cancer Genome Atlas (TCGA) database. The relationship between co-expression modules and clinical traits was investigated by Pearson correlation analysis. Furthermore, the prognostic value and expression level of the hub genes of these modules were validated based on data from the TCGA database and other independent datasets from the Gene Expression Omnibus (GEO) database and the Human Protein Atlas database. The significant modules and hub genes were also assessed by functional analysis and gene set enrichment analysis (GSEA). Results We found that the turquoise module was strongly correlated with pathologic T stage and significantly enriched in critical functions and pathways related to tumourigenesis. PPP1R12B, CFD, CRYAB, FAM189A2 and ANGPTL1 were identified and statistically validated as hub genes in the turquoise module and were closely implicated in the prognosis of OSCC. GSEA indicated that five hub genes were significantly involved in many well-known cancer-related biological functions and signaling pathways. Conclusion In brief, we systematically discovered a co-expressed turquoise module and five hub genes associated with the pathologic T stage for the first time, which provided further insight that WGCNA may reveal the molecular regulatory mechanism involved in the carcinogenesis and progression of OSCC. In addition, the five hub genes may be considered candidate prognostic biomarkers and potential therapeutic targets for the precise early diagnosis, clinical treatment and prognosis of OSCC in the future.

Pomelo fruitlets have the potential for extracting cellulose. This study aimed to investigate characterization and functionality of cellulose extracted from pomelo fruitlets by different extraction methods. Cellulose extracted by acidic-alkaline hydrogen peroxide hydrolysis (CAA), alkaline hydrogen peroxide hydrolysis (CA), and ultrasonic assisted alkaline hydrogen peroxide hydrolysis (CUA) were prepared from pomelo fruitlets. The results showed that cellulose CUA had higher yield and purity with higher crystallinity and smaller particle size than those of CAA or CA (p < 0.05). Specifically, the yield of CUA was 82.75% higher than that of CAA, and purity was increased by 26.42%. Additionally, water- and oil-holding capacities of CUA were superior to those of CAA or CA, increasing by 13–23% and 10–18%, respectively. The improvement of water- and oil-holding capacities were highly related to its smaller particle size with increased surface area. The results suggested that ultrasonic assisted alkaline hydrogen peroxide hydrolysis is a promising and efficient method to prepare high-purity cellulose from pomelo fruitlets, and this cellulose is expected to be a food stabilizer and pharmaceutical additive.

The aim of this study was to investigate the synergistic antitumor activity of rhein and doxorubicin (DOX) and to elucidate the underlying mechanisms in hepatocellular SMMC-7721 and HepG2 cells. Cell growth curves, caspase-3 activity, and intracellular DOX accumulation were observed using an IncuCyte real-time video imaging system. Combination index was used to calculate synergistic potential of rhein and DOX. Cell apoptosis was detected by the Annexin V-FITC/PI apoptosis kit. Lactate dehydrogenase and adenosine triphosphate (ATP) levels were assessed using an assay kit. Oxygen consumption rates (OCR) and extracellular acidification rates were assessed by the Seahorse XFe96 Extracellular Flux Analyzer. Mitochondrial inner membrane potential (ΔΨm) was monitored with JC-1 fluorescence. Western blot analysis was used to detect the level of P-glycoprotein. Synergistic antiproliferative and proapoptotic effects were exerted by the combination of rhein at 10 μM and DOX at 2 μM in SMMC-7721 and HepG2 cells. Rhein could influenced the accumulation of DOX in both cells, which was associated with remarkably decreased mitochondrial energy metabolism and ATP levels. Rhein could reduce ΔΨm in both cells. mPTP, opener atractyloside (ATR) could accelerate the loss of ΔΨm, and further suppress the OCR induced by rhein. In contrast, the mPTP blocker cyclosporin A (Cs A) inhibited the loss of ΔΨm and the OCR induced by rhein. Our data indicate that a decline in mitochondrial energy metabolism was responsible for the synergistic antitumor effects of rhein and DOX in hepatocellular carcinoma cells. Reduction of ΔΨm and opening of mPTP inhibited the exchange of ATP/adenosine diphosphate between mitochondrial matrix and cytoplasm is the important mechanism.

Ziziphus jujuba Mill. has been used as both an edible fruit and Chinese medicine for a long time. In this study, the chemical profiles in terms of reducing sugars, organic acids, and minerals of 15 cultivars of jujube were analyzed. The reducing sugars and organic acids were measured by HPLC-UV (high performance liquid chromatography with ultraviolet detection). Minerals were detected by ICP-OES (inductively coupled plasma-optical emission spectrometry). Glucose (85.9–1005 mg/100 g FW), malic acid (120–509 mg/100 g FW), citric acid (29.4–181 mg/100 g FW), iron (5.27–12.5 mg/100 g DW), calcium (16.2–30.2 mg/100 g DW) and magnesium (51.2–70.0 mg/100 g DW) were found to be the major components in the fruits. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used, in order to classify these cultivars based on the aforementioned chemical profiles. According to the PCA, classification based on the content of reducing sugars is more reasonable and reliable than other parameters. In this classification, 15 cultivars were categorized into 6 groups.

Astaxanthin is a natural pigment that possesses benefit potentials to prevent obesity, however, its underlying mechanism is not clarified. In the current study, Phaffia rhodozyma astaxanthin was prepared and its inhibitory effect on pancreatic lipase was evaluated. The results showed that astaxanthin significantly inhibited the activity of pancreatic lipase in a dose-dependent manner within the tested concentration ranges. The kinetic analysis demonstrated that astaxanthin noncompetitively inhibited pancreatic lipase activity. In addition, astaxanthin induced secondary structure changes which resulted in decreased enzyme activities. Furthermore, the molecular docking analysis revealed that astaxanthin blocked the channel of catalytic site to delay substrate entrance or prevent product diffusion through changing the catalytic site conformation. These findings not only shed light on the underlying inhibitory mechanism of astaxanthin on pancreatic lipase, but also provide scientific evidence for extending the application of astaxanthin in functional food industries.

The central cholinergic nervous system plays an important role in cognition, with acetylcholine hypofunction considered to be a major factor of dementia. Botulinum toxin type A (BoNT/A), a potent poison secreted by Clostridium botulinum, is used widely for dystonia treatment and facial cosmesis. BoNT/A injection inhibits acetylcholine release in the neuromuscular junction through cleavage of synaptosomal-associated protein of 25 kDa in cholinergic terminals. Furthermore, beyond the injection site, BoNT/A undergoes retrograde transport and transcytosis to the central nervous system from peripheral cholinergic terminals. However, whether peripheral BoNT/A injection affects the function of the central nervous system and induces learning deficits remains unclear. We injected mice with different doses of BoNT/A (2, 10, and 50 U/kg) or sterile saline (control) into the left whisker pad to test spatial learning performance at different times after injection using the Morris water maze. At 3 days and 4 weeks after injection, the spatial learning ability of the control and BoNT/A-treated mice showed no significant differences. Surprisingly, however, rather than spatial learning impairment at 6 weeks after injection, BoNT/A-treated mice spent less time than control mice in locating the experimental platform, indicating that BoNT/A facial injection might promote spatial learning. Furthermore, our study suggests that facial application of BoNT/A is safe and could play a positive role in ameliorating the spatial learning deficits associated with neurodegenerative diseases.

By the hydrothermal technique, two new organic–inorganic hybrids, tetra-Zr-substituted sandwich-type germanotungstate clusters functionalized by different organic amines H10K4[Zr4(μ3-O)2(μ-OH)2(enMe)2(B-α-GeW10O37)2]·6DMF·18H2O (1) and H10K2Na2[Zr4(μ3-O)2(μ-OH)2(en)2(B-α-GeW10O37)2]·4 DMF·22H2O (2) (enMe = 1,2-diaminopropane, en = ethylenediamine, DMF = N,N-dimethylformamide) have been obtained, which have been characterized by single-crystal X-ray structure analysis, powder X-ray diffraction (PXRD), elemental analysis, FT-IR spectra and thermogravimetric analysis (TGA), respectively. The structure analysis reveals that 1 and 2 exhibit similar sandwich-type polyoxoanion built by two [Zr2(μ3-O)(μ-OH)(enMe)(B-α-GeW10O37)] or [Zr2(μ3-O)(μ-OH)(en)(B-α-GeW10O37)] clusters, showing the first germanotungstate clusters with Zr-containing 5-membered ring formed from the chelation coordination pattern of Zr4+ and organic amine. To compounds 1 and 2, the cluster units, [Zr4(μ3-O)2(μ-OH)2(enMe)2(B-α-GeW10O37)2] and [Zr4(μ3-O)2(μ-OH)2(en)2(B-α-GeW10O37)2], are linked by K+ cations to form 1-D chains, respectively.

Ethnopharmacological relevance Dahuang zhechong pill (DHZCP) is a famous traditional Chinese medicinal prescription from the “Synopsis of Prescriptions of the Golden Chamber (Jin Kui Yao Lue)”,Lue)”, an ancient Chinese medical classic. DHZCP is commonly used for clinical treatment of liver cancer by promoting blood circulation to dissolve blood stasis and by removing pathogenic vegetations.vegetations. DHZCP-based treatment has been derived from Traditional Chinese Medicine (TCM) and is officially recorded in the Chinese Pharmacopoeia. Aim of the study The aim of this study was to investigate the ability of DHZCP to reverse doxorubicin (DOX) resistance of SMMC-7721 cells in a xenograft mouse model, and to explore the underlying mechanisms. Materials and methods Liquid chromatography–mass spectrometry was used to verify the composition of DHZCP. H&E staining was used to observe the pathological changes in hepatocellular carcinoma samples. Intracellular DOX accumulation was observed as intrinsic fluorescence by microscopy. Cell apoptosis was detected by the TUNEL assay. Human antibody arrays were used to analyze the expression of apoptotic- and angiogenic-related proteins. ATP levels were assessed and western blots were used to detect the protein expression of key enzymes of energy metabolism. Results DHZCP significantly reduced the tumor volume and weight of subcutaneous xenografts of drug-resistant hepatoma cells, and combining DHZCP with lower doses of DOX significantly increased the content of DOX in tumor tissue, increased the apoptosis of hepatoma cells, and reversed Dox resistance. With respect to 43 apoptosis-associated proteins, DHZCP regulated the expression of 5 of them. When combined with low-dose DOX, the expression of 40 apoptosis-related proteins was significantly altered. With respect to 23 angiogenesis-associated proteins, DHZCP upregulated the expression of endostatin and inhibited the expression of matrix metallopeptidase 9. When combined with low-dose DOX, DHZCP significantly downregulated protein expression of urokinase receptor, as well as vascular endothelial growth factor receptors 2 and 3. Especially, DHZCP significantly inhibited the expression of key enzymes of the tricarboxylic acid cycle and of oxidative phosphorylation, reducing the level of ATP in tumor tissue. Conclusions DHZCP inhibited the growth of DOX-resistant hepatocellular carcinoma subcutaneous xenografts in nude mice and promoted increased apoptosis caused by DOX, thus reversing DOX resistance. This was associated with a decline in energy metabolism and regulated expression of pro-apoptotic proteins.

Coptidis Rhizoma (CR), the dried rhizome of three perennial Coptis specices, was widely used as a famous herbal medicine in China. Although the quantification of main alkaloids in CR has been extensively conducted, the existing analytical methods suffer from some flaws that restrict the general applicability in the routine quality assessment. In this work, we constructed an optimized method for quality evaluation and species discrimination of CR by ion-pairing high performance liquid chromatography (IP-HPLC) combined with response surface methodology (RSM). By employing Box-Behnken designs (BBD), 30 sets of experimental runs were performed to build the response surface models, and Derringer's desirability was used to optimize the IP-HPLC separation conditions by simultaneously taking resolutions between two pairs of hardly - separated alkaloids and the retention time of the last eluted analyte as optimization criteria. Meanwhile, a single standard to determine multi-components (SSDMC) method based on the optimized IP-HPLC was set up and fully validated, to simultaneously determine six alkaloids including jatrorrhizine (JAT), columbamine (COL), epiberberine (EPI), coptisine (COP), palmatine (PAL) and berberine (BER), using BER as internal standard. Finally, the quantitative data from 33 batches of CR samples were comparatively analyzed, and the ratios of JAT/COL and EPI/JAT were discovered for species classification. Collectively, the established IP-HPLC method can be adopted for comprehensive quality evaluation and species discrimination of CR due to its general applicability.

The glycoside hydrolase, α-l-rhamnosidase, could remove the bitter taste of naringin from citrus juices. However, most α-l-rhamnosidases are easily deactivated at high temperatures, limiting the practice in debittering citrus juices. The V529A mutant of the α-l-rhamnosidase r-Rha1 from Aspergillus niger JMU-TS528 was developed with improved thermostability using directed evolution technology and site-directed mutagenesis. The enzyme mutant had a half-live of thermal inactivation T(1/2) of 1.92 h, 25.00 min, and 2 min at 60, 65, and 70 °C, respectively. In addition, it had improved substrate affinity and better resistance to the inhibition of glucose. The improved substrate affinity was related to its lowered binding energy. Most significantly, the naringin content was reduced to below the bitter taste threshold by treatment with 75 U/mL of the mutant during the preheating process of orange juice production. The comprehensive results indicate that thermostability improvement could promote the practical value of α-l-rhamnosidase in citrus juice processing.

Background High amounts of insoluble substrates exist in the traditional solid-state fermentation (SSF) system. The presence of these substrates complicates the determination of microbial biomass. Thus, enzyme activity is used as the sole index for the optimization of the traditional SSF system, and the relationship between microbial growth and enzyme synthesis is always ignored. This study was conducted to address this deficiency. All soluble nutrients from tea stalk were extracted using water. The aqueous extract was then mixed with polyurethane sponge to establish a modified SSF system, which was then used to conduct tannase production. With this system, biomass, enzyme activity, and enzyme productivity could be measured rationally and accurately. Thus, the association between biomass and enzyme activity could be easily identified, and the shortcomings of traditional SSF could be addressed. Results Different carbon and nitrogen sources exerted different effects on microbial growth and enzyme production. Single-factor experiments showed that glucose and yeast extract greatly improved microbial biomass accumulation and that tannin and (NH4)2SO4 efficiently promoted enzyme productivity. Then, these four factors were optimized through response surface methodology. Tannase activity reached 19.22 U/gds when the added amounts of tannin, glucose, (NH4)2SO4, and yeast extract were 7.49, 8.11, 9.26, and 2.25%, respectively. Tannase activity under the optimized process conditions was 6.36 times higher than that under the initial process conditions. The optimized parameters were directly applied to the traditional tea stalk SSF system. Tannase activity reached 245 U/gds, which is 2.9 times higher than our previously reported value. Conclusions In this study, a modified SSF system was established to address the shortcomings of the traditional SSF system. Analysis revealed that enzymatic activity and microbial biomass are closely related, and different carbon and nitrogen sources have different effects on microbial growth and enzyme production. The maximal tannase activity was obtained under the optimal combination of nutrient sources that enhances cell growth and tannase accumulation. Moreover, tannase production through the traditional tea stalk SSF was markedly improved when the optimized parameters were applied. This work provides an innovative approach to bioproduction research through SSF. Electronic supplementary material The online version of this article (10.1186/s13068-018-1093-0) contains supplementary material, which is available to authorized users.

Background: A new ι-carrageenase-producing strain was screened from mangroves and authenticated as Pseudoalteromonas carrageenovora ASY5 in our laboratory. The potential application of this new strain was evaluated. Results: Medium compositions and culturing conditions in shaking flask fermentation were firstly optimized by single-factor experiment. ι-Carrageenase activity increased from 0.34 U/mL to 1.08 U/mL after test optimization. Optimal fermentation conditions were 20°C, pH 7.0, incubation time of 40 h, 15 g/L NaCl, 1.5% (w/v) yeast extract as nitrogen source, and 0.9% (w/v) ι-carrageenan as carbon source. Then, the crude ι-carrageenase was characterized. The optimum temperature and pH of the ι-carrageenase were 40°C and 8.0, respectively. The enzymatic activity at 35–40°C for 45 min retained more than 40% of the maximum activity. Meanwhile, The ι-carrageenase was inhibited by the addition of 1 mmol/L Cd2+ and Fe3+ but increased by the addition of 1 mmol/L Ag+, Ba2+, Ca2+, Co2+, Mn2+, Zn2+, Fe2+, and Al3+. The structure of oligosaccharides derived from ι-carrageenan was detected using electrospray ionization mass spectrometry (ESI-MS). The ι-carrageenase degraded ι-carrageenan, yielding disaccharides and tetrasaccharides as main products. Conclusions: The discovery and study of new ι-carrageenases are beneficial not only for the production of ι-carrageenan oligosaccharides but also for the further utilization in industrial production. Keywords: Disaccharides, Electrospray ionization mass spectrometry (ESI-MS), Enzyme properties, Fermentation optimization, Galactans, Pseudoalteromonas carrageenovora, Sulfated linear polysaccharides, Tetrasaccharides, ι-Carrageenan oligosaccharides, ι-Carrageenan, ι-Carrageenase-producing strain

This study aimed to improve the thermostability of arylsulfatase from Pseudoalteromonas carrageenovora. A total of 10 single-site mutants were chosen using the PoPMuSiC program, and two mutants of K253N and P314T showed enhanced thermal stability. By saturation mutagenesis and thermostability analysis, K253H and P314T were the best mutants at the two sites. Combinational mutations of K253H, P314T and H260L were subsequently introduced, and the best mutant of K253H/H260L was selected. Thermal inactivation analysis showed the half-life (t1/2) value at 55°C for K253H/H260L was 7.7-fold that of the wild-type enzyme (WT), meanwhile this mutant maintained the specific enzyme activity. Structure modeling demonstrated that the additional hydrogen bonds, optimization of surface charge-charge interactions, and increasing of hydrophobic interaction could account for the improved thermostability imparted by K253H/H260L.

Background: Automated peritoneal dialysis (APD) can cater to individual needs, provide treatment while asleep, take into account the adequacy of dialysis, and improve the quality of life. Currently, independent research and development of APD machines made in China are more conducive to patients. A randomized, multicenter, crossover study was conducted by comparing an APD machine made in China with an imported machine. The safety, effectiveness, and manipulability of the two machines were compared. Methods: Two hundred and sixty patients who underwent peritoneal dialysis (PD) on a regular basis in 18 centers between August 2015 and February 2016 were included. The inclusion criteria include age ≥18 years and PD ≥30 days. The exclusion criteria were as follows: hemodialysis; exit site or tunnel infection; and peritonitis ≤30 days. The patients were randomly divided into Group A, who were first treated with a FM machine made in China, then changed to an imported machine; and Group B, who were treated using the reverse sequence. APD treatment was performed with 10 L/10 h and 5 cycles of exchange. After 72 h, the daily peritoneal Kt/V, the accuracy of the injection rate, accuracy of the injection temperature, safety, and manipulability of the machine were assessed. Noninferiority test was conducted between the two groups. Results: The daily peritoneal Kt/V in the APD machine made in China and the imported APD machine were 0.17 (0.14, 0.25) and 0.16 (0.13, 0.23), respectively. There was no significant difference between the groups (Z = 0.15, P = 0.703). The lower limit of the daily Kt/V difference between the two groups was 0.0069, which was greater than the noninferiority value of −0.07 in this study. The accuracy of the injection rate and injection temperature was 89.7% and 91.5%, respectively, in the domestic APD machine, which were both slightly better than the accuracy rates of 84.0% and 86.8% in the imported APD machine (89.7% vs. 84.0%, P = 0.2466; 91.5% vs. 86.8%, P = 0.0954). Therefore, the APD machine made in China was not inferior to the imported APD machine. The fuselage of the imported APD machine was space-saving, while the APD machine made in China was superior with respect to body mobility, man-machine dialog operation, alarm control, and patient information recognition. Conclusions: The FM machine made in China was not inferior to the imported APD machine. In addition, the FM machine made in China had better operability. Trial Registration: Clinicaltrials.gov, NCT02525497; https://clinicaltrials.gov/ct2/results?cond=&term=NCT02525497&cntry=& state=&city=&dist=.

Background estimation is essential in many computer vision applications with video frames. It refers to two important issues: accuracy and efficiency. There are mainly two challenges: how to recover the background image from as few frames as possible, and how to get a background image as fast as possible from a long video sequence. This Letter proposed a fast background estimation approach based on matrix completion to solve the second issue. Considering that matrix completions set all frames to be column vectors in a big matrix. While sequential images are to some extent related and redundant frames exist, the authors' approach implements a frame selection step to decrease the number of frames before using fast robust principal component analysis (RPCA) to deal with matrix completion problem. Their experiments selected long video sequences from scene background initialisation (SBI) dataset. Results show that compared with existing RPCA matrix completion algorithms and other state-of-the-art methods, their method is much better in processing efficiency while still keeps the same good performance.

Docosahexaenoic acid (DHA), a member of ω−3 polyunsaturated fatty acids (PUFAs), plays an essential effect in the amelioration of human health. Schizochytrium limacinum SR21 is considered as a potential microalgae for DHA production. The carbon source regulates cell metabolism and PUFAs synthesis in S. limacinum. Flask and fed-batch cultivations were conducted to explore the influence of glycerol and glucose on the biomass, growth rate, and DHA content of S. limacinum SR21. In flask cultivation, the highest cell growth rate (12.2 g/L/day) was obtained when glucose was employed as the sole carbon source, whereas the DHA content reached the maximum value (46.88%) in the medium with glycerol as the sole carbon source. Fed-batch fermentation showed that glycerol had comparable biomass 171 g/L, higher DHA yield (40.7 g/L), and higher DHA production rate (223.8 mg/L/h) compared with glucose as the sole carbon source. We combined the advantages of the two carbon sources and developed a new two-stage fed-batch fermentation strategy using mixed carbon sources (glucose and glycerol). This strategy showed an increase in DHA production rate (229.8 mg/L/h) in comparison with the sole carbon sources. Comparative metabolomics analysis indicated that glycerol added in the medium up-regulated the pentose phosphate and glycolysis pathways. Moreover, tricarboxylic acid cycle and mevalonate pathway were dampened. These outcomes provide metabolic basis for enhancing DHA production rate by S. limacinum SR21.

Sustainability has become a major focus of the cement industry, largely due to the carbon dioxide emissions associated with Portland cement production. In grouting engineering, ordinary cement slurry has high viscosity, poor fluidity and groutability and is prone to blockage. In this study, a cement slurry was designed using superfine cement (SC). Fine-grained ultrafine fly ash (UFA) waste was used, part of which is used to replace cement, and a certain amount of nontoxic mSiO2·nH2O (SH) is extracted from limestone waste and mixed with the commonly used admixture polycarboxylic acid water reducer (PAWR) to ensure its physical properties in practical engineering applications while reducing its viscosity, increasing its fluidity, and reducing the occurrence of clogging. To determine the optimal mix ratio of the cement slurries mixed with various materials, the characteristics of each material were analyzed through the single-factor test of the multiperformance test, and the orthogonal test mix ratio was designed based on the single-factor test results. Through the Taguchi grey correlation analysis method, the orthogonal test data were analyzed to find the optimal mix ratio. A performance test of the cement slurry with the optimal mix ratio was carried out, and its sustainability was analyzed. Combined with the Discrete Element Method (DEM) and the Voronoi Calculation Method (VCM) methods, UDEC numerical simulation software is used to simulate and analyze the general laws of cement slurry fluidity. The results show that the cement slurry with the optimal mix ratio of SH, SC, PAWR and UFA materials has good fluidity and groutability, has the characteristics of sustainable development, and can be applied to practical projects.

Fifteen individual perfluoroalkyl substances (PFASs) were analyzed in 22 sediment samples collected from Anqing urban lakes (Anhui province, China) by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS). Total PFAS concentration was between 0.61 and 26 ng g− 1 dry weight. Perfluorooctane sulfonate (PFOS) was the dominant PFAS contaminant, with a concentration range of

Limonin is a bioactive compound that is traditionally extracted from citrus seeds using organic solvents or alkaline/metal ion solutions. In the present study, pummelo [Citrus grandis] peel was investigated for limonin preparation using a novel process consisting of water extraction, ammonium sulfate precipitation and resin adsorption. The pummelo peel was determined to have 4.7mg/g limonin, which could be extracted by water and further recovered by ammonium sulfate precipitation with a yield of 2.4mg/g, which was similar to that of traditional process using ethanol extraction and vacuumed evaporation. The precipitated limonin was purified by resin adsorption and crystallization with a purity of 96.4%. In addition, the limonin was identified via the analyses of retention time, infrared spectrum and nuclear magnetic resonance. This study indicates a novel and eco-friendly process for recovering limonin, providing a new candidate for limonin preparation.

The paper aims at investigating the shear creep property and creep model of marble with structural plane. Marble specimens were taken from diversion tunnel engineering of Jinping II hydropower stat...

Background Inferior Tieguanyin oolong tea leaves were treated with tannase. The content and bioactivity of catechins in extracts from the treated tea leaves were investigated to assess the improvement in the quality of inferior Tieguanyin oolong tea. Results Analysis showed that after treatment, the esterified catechin content decreased by 23.5%, whereas non-galloylated catechin and gallic acid contents increased by 15.3% and 182%, respectively. The extracts from tannase-treated tea leaves showed reduced ability to bind to BSA and decreased tea cream levels. The extracts also exhibited increased antioxidant ability to scavenge OH and DPPH radicals, increased ferric reducing power, and decreased inhibitory effects on pancreatic α-amylase and lipase activities. Conclusions These results suggested that tannase treatment could improve the quality of inferior Tieguanyin oolong tea leaves.

A library of Pseudoalteromonas carrageenovora arylsulfatase mutants was constructed by introducing random mutagenesis using error-prone PCR. After screening, one mutant strain was obtained whose arylsulfatase had improved thermal stability. Protein sequence analysis revealed one amino acid substitution of H260L. The mutant arylsulfatase (named H260L) retained higher residual activity than wild-type enzyme (named WT) after incubation at 45, 50, 55 and 60°C for 60min. Thermal inactivation analysis showed that the half-life (t1/2) value at 55°C for H260L was 40.6min, while that of WT was 9.1min. When p-nitrophenyl sulfate was used as a substrate, the optimal reaction temperature and pH for the mutant enzyme were 55°C and pH 8.0, respectively. H260L was stable over the pH range of 6.0-9.0. Inhibition assay with EDTA indicated that metal ions play an important role during the catalytic process of the mutant enzyme. The desulfation ratio against agar of Gracilaria lemaneiformis was 82%.

Background: A simple and efficient strategy for agarase immobilization was developed with carboxyl-functionalized magnetic nanoparticles (CMNPs) as support. The CMNPs and immobilized agarase (agarase-CMNPs) were characterized by transmission electron microscopy, dynamic light scattering, vibrating sample magnetometry, scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and zeta-potential analysis. The hydrolyzed products were separated and detected by ESI-TOF-MS. Results: The agarase-CMNPs exhibited a regular spherical shape with a mean diameter of 12 nm, whereas their average size in the aqueous solution was 43.7 nm as measured by dynamic light scattering. These results indicated that agarase-CMNPs had water swelling properties. Saturation magnetizations were 44 and 29 emu/g for the carriers and agarase-CMNPs, respectively. Thus, the particles had superparamagnetic characteristics, and agarase was successfully immobilized onto the supports. Agaro-oligosaccharides were prepared with agar as substrate using agarase-CMNPs as biocatalyst. The catalytic activity of agarase-CMNPs was unchanged after six reuses. The ESI-TOF mass spectrogram showed that the major products hydrolyzed by agarase-CMNPs after six recycle uses were neoagarotetraose, neoagarohexaose, and neoagarooctaose. Meanwhile, the end-products after 90 min of enzymatic treatment by agarase-CMNPs were neoagarobiose and neoagarotetraose. Conclusions: The enhanced agarase properties upon immobilization suggested that CMNPs can be effective carriers for agarase immobilization. Agarase-CMNPs can be remarkably used in developing systems for repeated batch production of agar-derived oligosaccharides. Normal 0 21 false false false ES-MX JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Cambria","serif"; mso-ansi-language:ES-MX;}

Carboxyl functioned magnetic nanoparticles (CMNPs) were prepared by a simple co-precipitation method and characterized by Fourier transform infrared spedtroscopy and scanning electron microscope. The prepared CMNPs were used for covalent immobilization of the arylsulfatase which could be applied in desulfation of agar. The optimal immobilizaion conditions were obtained as follows: glutaraldehyde concentration 1.0% (v/v), cross-linking time 3h, immobilization time 3h, immobilization temperature 5°C and enzyme dose 0.62U. Increase in properties of the arylsulfatase such as optimum temperature and pH was observed after immobilization. Immobilization led to increased tolerance of enzyme to some metal ions, inhibitors and detergents. The Km and kcat of the immobilized enzyme for hydrolysis of p-NPS at pH 7.5 and at 50°C were determined to be 0.89mmol/L and 256.91s-1, respectively. The relative desulfuration rates of immobilized arylsulfatase maintained 61.7% of its initial desulfuration rates after seven cycles. After the reaction of agar with immobilized arylsulfatase for 90min at 50°C, 46% of the sulfate in the agar was removed. These results showed that the immobilization of arylsulfatase onto CMNPs is an efficient and simple way for preparation of stable arylsulfatase and have a great potential for application in enzymatic desulfation of agar.

Two-dimensional (2D) reduced graphene oxide–carbon dot (rGO–CD) hybrids were synthesized via a green one-pot method, in which the reduction of GO is accompanied by in situ generation of CDs with ultra-small sizes of 3–8 nm on its surface. The introduction of CDs enhanced the gas sensing properties by ∼3.3 times compared to bare rGO, and the rGO–CD hybrids could detect an extremely low NO2 concentration (10 ppb) at room temperature. Upon exposure to 25 ppm NO2 at room temperature, the as-prepared rGO–CDs show a sensitivity of ∼120% and exhibit excellent selectivity for NO2. After six consecutive gas sensing tests or unencapsulated storage for 90 days, the rGO–CD hybrids still retained their sensing characteristics. The enhanced gas sensing properties of the rGO–CDs can be attributed to the increased hole density on the surfaces of rGO due to the introduction of CDs as well as the formation of all-carbon nanoscale heterojunctions with few residual N atoms, significantly promoting charge transfer. It is believed that this low-cost and environmental strategy provides a facile route to design and fabricate a high sensitivity, stability and repeatability NO2 gas sensor based on 2D materials.

During a survey of plant parasitic nematodes in 2019, at Gansu Province, China, the stunt nematode Tylenchorhynchus zeae was found parasitizing corn seedlings. Females, males and juveniles of T. zeae were observed on soil and roots samples of corn after processing and extraction. This population of stunt nematodes was identified based on morphological and by sequencing the ITS1 region of rDNA and D2/D3 fragments of the 28 S rRNA. The ITS1 and the D2/D3 sequences of this population, shared 99.00 to 99.05% and 99.43 to 99.73% of similarity with sequences corresponding to T. zeae in GenBank, respectively. This is the first report of T. zeae infecting corn in Gansu Province, northwest China.

Background Phaffia rhodozyma is a potential industrial source for production of natural astaxanthin. The synthetic mechanism of astaxanthin in P. rhodozyma is complex and unclear that blocked its development. Results In this study, eight genes related to dicyclic and monocyclic pathway in three different strains of P. rhodozyma were analyzed, and the relationship between the expression and astaxanthin biosynthesis was explored. Among these genes, crtYB (R=0.75, Pasy genes (R=0.74, PcrtYB and asy genes were knocked out by homologous recombination. After crtYB knock-out, astaxanthin was decreased to be under detected line. It suggested crtYB played a role in dicyclic and monocyclic pathway. Meanwhile, the asy gene was in dicyclic pathway of astaxanthin biosynthesis, and its knock-out would promote the astaxanthin biosynthesis in monocyclic pathway, resulting in a 25.04% increase in astaxanthin production. Conclusion The possible rate-limiting enzymes were asy gene and crtYB illustrated by analysis of regression. Knock-out of asy and crtYB gene was great helpful to understand the synthetic pathway of astaxanthin, and significant to the industrial application of producing astaxanthin.

In this study, a low-molecular-weight saccharide fragment (LMWAs-L) was prepared from alginate lyase (EC 4.2.2.3) hydrolyzed ascophyllan by ultra-filtration separation method. LMWAs-L was a homogeneous saccharide fraction with an average molecular weight of 6.96 kDa. Enzymolysis process optimization experiments revealed that the optimum process parameters for preparing LMWAs-L were the enzyme concentration 0.02 U/mL, initial pH 6.8, and enzymolysis temperature 43 °C. After optimization, the yield of LMWAs-L was increased to 9.74% higher than that without optimization. Interestingly, LMWAs-L exhibited stronger enhancing activities on the proliferation and migration of human skin fibroblasts cells in vitro and better antibacterial activities as compared to native ascophyllan at the same mass concentration. Our study establishes a simple way to prepare low-molecular-weight saccharide with beneficial bioactivities from ascophyllan efficiently. This is the first report to reveal that ascophyllan and its low-molecular-weight saccharide have the potentials to be developed as natural biological dressing and antibacterial agents.

The unpleasant stale note is a negative factor hindering the consumption of instant ripened Pu-erh tea products. This study focused on investigating volatile chemicals in instant ripened Pu-erh tea that could mask the stale note via sensory evaluation, gas chromatography-mass spectrometry (GC-MS), and gas chromatography-olfactometry (GC-O) analyses. GC-MS and GC-O analyses showed that linalool, linalool oxides, trans-&beta, ionone, benzeneacetaldehyde, and methoxybenzenes were the major aroma contributors to the simultaneous distillation and extraction (SDE) extract of instant ripened Pu-erh tea. Sensory evaluation showed that the SDE extract had a strong stale note, which was due to methoxybenzenes. By investigating suppressive interaction among flavour components, the stale note from methoxybenzenes was shown to have reciprocal masking interactions with sweet, floral, and green notes. Moreover, the validation experiment showed that the addition of 40 &mu, g/mL of trans-&beta, ionone in the instant ripened Pu-erh tea completely masked the stale note and improved the overall aromatic acceptance. These results elucidate the volatile chemicals that could mask the stale note of instant ripened Pu-erh tea products, which might help to develop high quality products made from instant ripened Pu-erh tea.

The adverse effects of triphenyltin (TPT) on aquatic systems have attracted much attention because TPT is widely used and prevalent in aquatic environments. Here, zebrafish embryos/larvae were exposed to TPT (0, 0.039, 0.39, and 3.9 nM; 0, 15, 150 and 1500 ng/L) for 7 or 14 days to determine its toxic effects on the hypothalamic–pituitary–thyroid (HPT) axis. The results showed that whole-body total T4 and T3 levels were significantly decreased, which was accompanied by the significant upregulation of the expression of the dio1, dio2 and ugt1ab genes after exposure to TPT for 7 and 14 days. Genes related to thyroid hormone synthesis (crh, tshβ, nis, tpo and tg) were upregulated at both 7 and 14 days after TPT exposure. This might have been due to the positive feedback regulation of the HPT axis, which is caused by a decrease in thyroid hormone in the whole body in zebrafish. In addition, the survival rates and body lengths were reduced after treatment with TPT for 7 and 14 days. This indicated that TPT caused adverse effect on the development of zebrafish embryos/larvae. In summary, the results suggested that TPT caused thyroid disruption and developmental toxicity in zebrafish larvae.

α-L-Rhamnosidase has attracted lots of attention due to its industrial potential applications. The applicability of α-L-rhamnosidase, however, was limited by their low ligand affinity on the industrial scale. In order to improve the affinity of α-L-rhamnosidase for industrial use, we investigated the variation of its affinity by amino acid replacement. Particularly, the enzyme affinity of a α-L-rhamnosidase from Aspergillus niger JMU-TS528 (rRha1) was measured with the semi-conservative amino acid (homology between 30% -80%) replaced. As a result, the enzyme affinity of the two mutants, R404S and N578D, were increased by 1.45-fold and 2.3-fold, respectively, showing that these two mutants could be the promising candidates for industrial use. To test if these mutations bring negative effect on the enzyme properties, we also determined the other enzymatic properties of these mutants and showed no negative effect. To understand the improvement of enzyme affinity, the conformational flexibility of (α/α)