| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Li, Peng, et al.
(författare)
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Transcriptional reactivation of OTX2, RX1 and SIX3 during reprogramming contributes to the generation of RPE cells from human iPSCs
- 2016
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Ingår i: International Journal of Biological Sciences. - : Ivyspring International Publisher. - 1449-2288. ; 12:5, s. 505-517
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Tidskriftsartikel (refereegranskat)abstract
- Directed differentiation of human induced pluripotent stem cells (iPSCs) into retinal pigmented epithelium (RPE) holds great promise in cell replacement therapy for patients suffering from degenerative eye diseases, including age-related macular degeneration (AMD). In this study, we generated iPSCs from human dermal fibroblasts (HDFs) by electroporation with episomal plasmid vectors encoding OCT4, SOX2, KLF4, L-MYC together with p53 suppression. Intriguingly, cell reprogramming resulted in a metastable transcriptional activation and selective demethylation of neural and retinal specification-associated genes, such as OTX2, RX1 and SIX3. In contrast, RPE progenitor genes were transcriptionally silent in HDFs and descendant iPSCs. Overexpression of OCT4 and SOX2 directly stimulated the expression of OTX2, RX1 and SIX3 in HDFs and iPSCs. Luciferase and chromatin immunoprecipitation (ChIP) assays further identified an OCT4- and two SOX2-binding sites located in the proximal promoter of OTX2. Histone acetylation and methylation on the local promoter also participated in the reactivation of OTX2. The transcriptional conversion of RX1 and SIX3 genes partially attributed to DNA demethylation. Subsequently, iPSCs were induced into the RPE cells displaying the characteristics of polygonal shapes and pigments, and expressing typical RPE cell markers. Taken together, our results establish readily efficient and safe protocols to produce iPSCs and iPSC-derived RPE cells, and underline that the reactivation of anterior neural transcription factor OTX2, eye field transcription factor RX1 and SIX3 in iPSCs is a feature of pluripotency acquisition and predetermines the potential of RPE differentiation.
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| 3. |
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| 4. |
- Joffrin, E., et al.
(författare)
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Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall
- 2019
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:11
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Forskningsöversikt (refereegranskat)abstract
- For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des. 82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T, leading up to 2020 and the first experiments with 50%/50% D-T mixtures since 1997 and the first ever D-T plasmas with the ITER mix of plasma-facing component materials. For this purpose, a concerted physics and technology programme was launched with a view to prepare the D-T campaign (DTE2). This paper addresses the key elements developed by the JET programme directly contributing to the D-T preparation. This intense preparation includes the review of the physics basis for the D-T operational scenarios, including the fusion power predictions through first principle and integrated modelling, and the impact of isotopes in the operation and physics of D-T plasmas (thermal and particle transport, high confinement mode (H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving several aspects of plasma operation for DTE2, such as real time control schemes, heat load control, disruption avoidance and a mitigation system (including the installation of a new shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the three-ions scheme), new diagnostics (neutron camera and spectrometer, active Alfven eigenmode antennas, neutral gauges, radiation hard imaging systems...) and the calibration of the JET neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation of JET for the 2020 D-T campaign provides an incomparable source of information and a basis for the future D-T operation of ITER, and it is also foreseen that a large number of key physics issues will be addressed in support of burning plasmas.
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| 5. |
- Murari, A., et al.
(författare)
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A control oriented strategy of disruption prediction to avoid the configuration collapse of tokamak reactors
- 2024
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Ingår i: Nature Communications. - 2041-1723 .- 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- The objective of thermonuclear fusion consists of producing electricity from the coalescence of light nuclei in high temperature plasmas. The most promising route to fusion envisages the confinement of such plasmas with magnetic fields, whose most studied configuration is the tokamak. Disruptions are catastrophic collapses affecting all tokamak devices and one of the main potential showstoppers on the route to a commercial reactor. In this work we report how, deploying innovative analysis methods on thousands of JET experiments covering the isotopic compositions from hydrogen to full tritium and including the major D-T campaign, the nature of the various forms of collapse is investigated in all phases of the discharges. An original approach to proximity detection has been developed, which allows determining both the probability of and the time interval remaining before an incoming disruption, with adaptive, from scratch, real time compatible techniques. The results indicate that physics based prediction and control tools can be developed, to deploy realistic strategies of disruption avoidance and prevention, meeting the requirements of the next generation of devices.
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| 6. |
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| 7. |
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| 8. |
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| 9. |
- Wen, Wanqing, et al.
(författare)
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Genome-wide association studies in East Asians identify new loci for waist-hip ratio and waist circumference
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Sixty genetic loci associated with abdominal obesity, measured by waist circumference (WC) and waist-hip ratio (WHR), have been previously identified, primarily from studies conducted in Europeanancestry populations. We conducted a meta-analysis of associations of abdominal obesity with approximately 2.5 million single nucleotide polymorphisms (SNPs) among 53,052 (for WC) and 48,312 (for WHR) individuals of Asian descent, and replicated 33 selected SNPs among 3,762 to 17,110 additional individuals. We identified four novel loci near the EFEMP1, ADAMTSL3, CNPY2, and GNAS genes that were associated with WC after adjustment for body mass index (BMI); two loci near the NID2 and HLA-DRB5 genes associated with WHR after adjustment for BMI, and three loci near the CEP120, TSC22D2, and SLC22A2 genes associated with WC without adjustment for BMI. Functional enrichment analyses revealed enrichment of corticotropin-releasing hormone signaling, GNRH signaling, and/or CDK5 signaling pathways for those newly-identified loci. Our study provides additional insight on genetic contribution to abdominal obesity.
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| 10. |
- Li, Li, et al.
(författare)
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Characterization of residential household dust from Shanghai by particle size and analysis of organophosphorus flame retardants and metals
- 2019
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Ingår i: Environmental Sciences Europe. - : Springer. - 2190-4707 .- 2190-4715. ; 31:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Physical and biological properties of dust particles might affect the availability and distribution of chemicals associated to indoor dust; however it has not been adequately examined. In this study, household dust from Shanghai was fractionated into five particle sizes and size distribution, morphology, surface area, organic matter, microorganisms, elemental composition, metals and organophosphorus flame retardants (OPFRs) compositions were characterized. Also, household dust samples from Stockholm that has previously been characterized were included in the analysis of OPFRs for comparison.Results: The respirable fraction had a yield of 3.3% in mass percentage, with a particle size of 2.22 +/- 2.04 mu m. As expected, both metals and OPFRs concentrations increased with decreased particle size. Al and Fe dominated (66-87%) followed by the concentrations of Zn (5-14%) and Ga (1.8-5%) of the sum of 16 metals in the dust. The concentrations of OPFRs in Shanghai dust ranged from 5.34 to 13.7 mu g/g (median: 7.21 mu g/g), compared to household dust from Stockholm that ranged from 16.0 to 28.3 mu g/g (median: 26.6 mu g/g). Tris(2-chloroisopropyl) phosphate (TCIPP) and tris(2-chloroethyl) phosphate (TCEP) dominated in Shanghai dust samples while tris(2-butoxyethyl) phosphate (TBOEP) dominated in dust from Stockholm homes.Conclusion: The results showed that mass percentage for each particle size fraction was not evenly distributed. Furthermore, the particle-bound microorganisms and OPFRs increased with decreased particle size, whereas metals had the highest concentrations at specific dust sizes. Therefore, it is essential to select the proper particle size in order to assess any specific human exposure study to indoor pollutants.
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| 11. |
- Niu, Dong, et al.
(författare)
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Novel brominated flame retardants in house dust from Shanghai, China : levels, temporal variation, and human exposure
- 2019
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Ingår i: Environmental Sciences Europe. - : Springer London. - 2190-4707 .- 2190-4715. ; 31:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Novel brominated flame retardants (NBFRs) have been increasingly used as alternatives to legacy BFRs (e.g., PBDEs and HBCDs) in consumer products, but are liable to emigrate and contaminate indoor dust. In this study, a total of 154 house dust samples including floor dust (FD) and elevated surface dust (ESD) were collected in the biggest metropolitan area (Shanghai) of East China in 2016. Limited information about temporal variation of NBFRs indoors is available, while the period of sampling is influential in human exposure estimates. Levels, temporal variation, and human exposure of seven target NBFRs such as decabromodiphenylethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EHTBB), and bis(2-ethylhexyl) tetrabromophthalate (BEHTEBP) were investigated in indoor house dust.Results: Concentrations of Sigma(7)NBFRs ranged from 19.11 to 3099ng/g with a geomean of 295.1ng/g in FD, and from 34.74 to 404.6ng/g with a geomean of 117.9ng/g in ESD. The geomeans of DBDPE were 219.6ng/g in FD and 76.89ng/g in ESD, accounting for 90.5% and 80.5% of Sigma(7)NBFRs. Levels of EHTBB, BTBPE, and DBDPE in FD exceeded significantly those in ESD. The temporal variation in Sigma(7)NBFRs in FD was ranked as summer>winter>autumn>spring. The daily exposure doses (DEDs) of Sigma(7)NBFRs via dust ingestion decreased as: infants>toddlers>children>teenagers>adults. Infants showed the highest DED in FD, 9.1ng/kg bw/day.Conclusions: DBDPE clearly dominated the NBFRs in both FD and ESD, but the concentrations of DBDPE in this study were generally moderate compared with the other international studies. Dust ingestion was the major pathway of human exposure to NBFRs indoors. About eightfold difference in exposure estimates between infants and adults showed that infants faced elevated exposure risks in FD. This study highlighted the necessity to estimate human exposure of NBFRs for different age groups using FD and ESD, respectively.
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| 12. |
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- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:1
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Forskningsöversikt (refereegranskat)
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| 13. |
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| 14. |
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| 15. |
- Bombarda, F., et al.
(författare)
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Runaway electron beam control
- 2019
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 61:1
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Tidskriftsartikel (refereegranskat)
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| 16. |
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| 17. |
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| 18. |
- Chen, Huijing, et al.
(författare)
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Application of olfactory ensheathing cells in clinical treatment of spinal cord injury : meta-analysis and prospect
- 2019
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Ingår i: JOURNAL OF NEURORESTORATOLOGY. - 2324-2426. ; 7:2, s. 70-81
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Tidskriftsartikel (refereegranskat)abstract
- Background:A number of clinical trials of olfactory ensheathing cells (OECs) for the treatment of chronic spinal cord injury (SCI) have been carried out all over the world. However, their safety and efficacy have not been basically evaluated. Moreover, there are no uniform standards laid out for the use of optimal source, transplantation method and the dosage of OECs.Objective:This study evaluated the source, dose, and route of transplantation of OECs for the treatment of chronic SCI.Methods: PubMed, Cochrane Library, EMBASE, CNKI, and Wanfang Data were searched for the clinical studies of OECs in the treatment of chronic SCI on July 2018.Results:A total of 30 articles on OECs transplantation for chronic SCI were selected for comprehensive evaluation of OECs sources, doses, and transplantation methods. The efficacy of OECs in the treatment of chronic SCI was evaluated using Review Manager 5.3.Conclusion:Fetal OECs are the primary source of cells for the treatment of chronic SCI in OECs, with standardized cell-culture and quality-control processes. Fetal OECs can significantly improve the neurological function of patients with chronic SCI. It is an ideal cell therapy for neurorestoration. However to explore more precise and minimally invasive treatment options are required in the future.
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| 19. |
- Chen, Liangkai, et al.
(författare)
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Physical frailty, adherence to ideal cardiovascular health and risk of cardiovascular disease : a prospective cohort study
- 2023
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Ingår i: Age and Ageing. - : Oxford University Press. - 0002-0729 .- 1468-2834. ; 52:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: longitudinal evidence concerning frailty phenotype and the risk of cardiovascular disease (CVD) remained insufficient, and whether CVD preventive strategies exert low CVD risk on frail adults is unclear.Objectives: we aimed to prospectively evaluate the association of frailty phenotype, adherence to ideal cardiovascular health (CVH) and their joint associations with the risk of CVD.Methods: a total of 314,093 participants from the UK Biobank were included. Frailty phenotype was assessed according to the five criteria of Fried et al.: weight loss, exhaustion, low physical activity, slow gait speed and low grip strength. CVH included four core health behaviours (smoking, physical activity and diet) and three health factors (weight, cholesterol, blood pressure and glycaemic control). The outcome of interest was incident CVD, including coronary heart disease, heart failure and stroke.Results: compared with the non-frail people whose incident rate of overall CVD was 6.54 per 1,000 person-years, the absolute rate difference per 1,000 person-years was 1.67 (95% confidence interval, CI: 1.33, 2.02) for pre-frail and 5.00 (95% CI: 4.03, 5.97) for frail. The ideal CVH was significantly associated with a lower risk of all CVD outcomes. For the joint association of frailty and CVH level with incident CVD, the highest risk was observed among frailty accompanied by poor CVH with an HR of 2.92 (95% CI: 2.68, 3.18).Conclusions: our findings indicate that physical frailty is associated with CVD incidence. Improving CVH was significantly associated with a considerable decrease in CVD risk, and such cardiovascular benefits remain for the frailty population.
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| 20. |
- Deng, Wenjun, et al.
(författare)
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Difference between Supine and Upright Blood Pressure Associates to the Efficacy of Midodrine on Postural Orthostatic Tachycardia Syndrome (POTS) in Children
- 2014
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Ingår i: Pediatric Cardiology. - : Springer Verlag (Germany). - 0172-0643 .- 1432-1971. ; 35:4, s. 719-725
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Tidskriftsartikel (refereegranskat)abstract
- Postural orthostatic tachycardia syndrome (POTS) is common, and has a serious impact on childrens quality of life. Midodrine hydrochloride, an alpha 1-adrenoreceptor agonist, is an effective treatment. The study was designed to examine the therapeutic efficacy of midodrine hydrochloride by quantifying changes in blood pressure during the head-up test (HUT), in children with POTS. Overall, 104 out of 110 children with POTS were treated with midodrine hydrochloride and successfully followed-up. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) changes were analyzed during the HUT. In a retrospective analysis, a receiver operating characteristic (ROC) curve was used to analyze the therapeutic predictive value of pre-treatment changes in SBP, DBP, and a combination of both, from the supine position to standing, in the subjects. The increase of SBP and DBP from the supine position to standing in responders were significantly lower than that of the non-responders. The ROC curve showed that midodrine hydrochloride for children with POTS would be predicted to be effective when the pre-treatment increase of SBP was a parts per thousand currency sign0 mmHg, or when the pre-treatment increase of DBP was a parts per thousand currency sign6.5 mmHg (from the supine position to standing), yielding a sensitivity of 72 % and specificity of 88 %. The area under the curve was 0.744 and 0.809, respectively. Hence, the results suggested that looking at the changes in blood pressure during the HUT was useful in predicting the response to midodrine hydrochloride in children with POTS.
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| 21. |
- Du, Xinyu, et al.
(författare)
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Distribution, behavior, and risk assessment of chlorinated paraffins in paddy plants throughout whole growth cycle
- 2022
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 167
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Tidskriftsartikel (refereegranskat)abstract
- Paddy plants provide staple food for 3 billion people worldwide. This study explores the environmental fate and behavior of a high-volume production emerging contaminants chlorinated paraffins (CPs) in the paddy ecosystem. Very-short-, short-, medium-, and long-chain CPs (vSCCPs, SCCPs, MCCPs, and LCCPs, respectively) were analyzed in specific tissue of paddy plants at four main growth stages and soils from the Yangtze River Delta, China throughout a full rice growing season. The total CP concentrations in the paddy roots, stalks, leaves, panicles, hulls, rice, and soils ranged from 181 to 1.74 × 103, 21.7–383, 19.6–585, 108–332, 245–470, 59.6–130, and 99.6–400 ng/g dry weight, respectively. The distribution profile indicated the translocation of SCCPs and MCCPs from soils to paddy tissue, highlighting their elevated bioaccumulative potential. The evolution of CP level/mass/pattern during the whole growth cycle suggested atmospheric CPs deposition on leaves and hulls, as well as stalk-rice transfer. CSOIL plant uptake model well predicted the level, distribution pattern, and bioconcentration factors (BCFs) of SCCPs and MCCPs in paddy shoot and recognized the soil-air-shoot pathway as the major contributor. Moreover, risk evaluation indicated that MCCPs intake and subsequent risks dominated the total exposure to CPs via rice ingestion. This is the first report on the occurrence, fate and risk assessment of all CPs classes in paddy ecosystems, and the results underline the potential health effects caused by the in-use MCCPs via rice ingestion.
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| 22. |
- Du, Xinyu, et al.
(författare)
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Evaluating oral and inhalation bioaccessibility of indoor dust-borne short- and median-chain chlorinated paraffins using in vitro Tenax-assisted physiologically based method
- 2021
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Ingår i: Journal of Hazardous Materials. - : Elsevier. - 0304-3894 .- 1873-3336. ; 402
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Tidskriftsartikel (refereegranskat)abstract
- Though ingestion and inhalation of dust have been suggested as important exposure routes contributing chlorinated paraffins (CPs) build-up in humans, the bioaccessibility of dust-borne CPs in the organ environment has not been well-studied, which may hinder an accurate estimation of exposure risks. In this study, the ingestion and inhalation bioaccessibility of dust-borne shortand median-chain CPs (SCCPs and MCCPs) was assessed using (colon-extended) physiologically based extraction test with the addition of Tenax. The ingestion bioaccessibility of SCCPs 51.5 %Cl, SCCPs 63 %Cl, MCCPs 42 %Cl, and MCCPs 57 %Cl was in ranges of 21.1-44.0 %, 11.7-45.8 %, 21.9-36.6 %, and 7.9-32.9 %, respectively. Multiple linear regression analysis demonstrated statistically significant associations of ingestion bioaccessibility with carbon chain length and chlorine substitution. The ingestion bioaccessibility of CPs also increased with co-existence of carbohydrate/protein. The inhalation bioaccessibility of SCCPs (16.7-38.7 % in artificial lysosomal fluid and 15.5-34.1 % in modified Gamble solution) was significantly higher than MCCPs (< 5 %), and varied with dust particle size/total organic carbon content. Our study indicates that modest bioaccessible fractions of CPs in dust should be taken into account to refine the estimation of human exposure, and their bioaccessibility may be affected by CP molecular size, nutritional content and dust property.
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| 23. |
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| 24. |
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| 25. |
- Fu, Xi, et al.
(författare)
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Association between indoor microbiome exposure and sick building syndrome (SBS) in junior high schools of Johor Bahru, Malaysia
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 753
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Tidskriftsartikel (refereegranskat)abstract
- Sick building syndrome (SBS) is a collection of nonspecific syndromes linked with the built environment. The occurrence of SBS is associated with humidity, ventilation, moulds and microbial compounds exposure. However, no study has reported the association between indoor microbiome and SBS. In this study, 308 students were surveyed for SBS symptoms from 21 classrooms of 7 junior high schools from Johor Bahru, Malaysia, and vacuum dust from floor, desks and chairs was collected. High throughput amplicon sequencing (16S rRNA gene and ITS region) and quantitative PCR were conducted to characterize the absolute concentration of bacteria and fungi taxa. In total, 326 bacterial and 255 fungal genera were detected in dust with large compositional variation among classrooms. Also, half of these samples showed low compositional similarity to microbiome data deposited in the public database. The number of observed OTUs in Gammaproteobacteria was positively associated with SBS (p = 0.004). Eight microbial genera were associated with SBS (p < 0.01). Bacterial genera, Rhodomicrobium, Scytonema and Microcoleus, were protectively (negatively) associated with ocular and throat symptoms and tiredness, and Izhakiella and an unclassified genus from Euzebyaceae were positively associated with the throat and ocular symptoms. Three fungal genera, Polychaeton, Gympopus and an unclassified genus from Microbotryaceae, were mainly positively associated with tiredness. The associations differed with our previous study in microbial compounds (endotoxin and ergosterol) and SBS in the same population, in which nasal and dermal symptoms were affected. A higher indoor relative humidity and visible dampness or mould in classrooms were associated with a higher concentration of potential risk bacteria and a lower concentration of potential protective bacteria (p < 0.01). This is the first study to characterize the SBS-associated microorganisms in the indoor environment, revealing complex interactions between microbiome, SBS symptoms and environmental characteristics.
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| 26. |
- Fu, Xi, et al.
(författare)
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Associations between environmental characteristics, high-resolution indoor microbiome, metabolome and allergic and non-allergic rhinitis symptoms for junior high school students
- 2023
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Ingår i: Environmental Science. - : Royal Society of Chemistry. - 2050-7887 .- 2050-7895. ; 25:4, s. 791-804
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Tidskriftsartikel (refereegranskat)abstract
- Rhinitis is one of the most prevalent chronic diseases globally. Microbiome exposure affects the occurrence of rhinitis. However, previous studies did not differentiate allergic rhinitis (AR) and non-allergic rhinitis (NAR) in the microbial association analysis. In this study, we investigate 347 students in 8 junior high schools, Terengganu, Malaysia, who were categorized as healthy (70.9%), AR (13.8%) and NAR (15.3%) based on a self-administered questionnaire and skin prick tests of pollen, pet, mould and house dust mite allergens. Classroom microbial and metabolite exposure in vacuumed dust was characterized by PacBio long-read amplicon sequencing, quantitative PCR and LC-MS-based untargeted metabolomics. Our findings indicate a similar microbial association pattern between AR and NAR. The richness in Gammaproteobacteria was negatively associated with AR and NAR symptoms, whereas total fungal richness was positively associated with AR and NAR symptoms (p < 0.05). Brasilonema bromeliae and Aeromonas enteropelogenes were negatively associated with AR and NAR, and Deinococcus was positively associated with AR and NAR (p < 0.01). Pipecolic acid was protectively associated with AR and NAR symptoms (OR = 0.06 and 0.13, p = 0.009 and 0.045). A neural network analysis showed that B. bromeliae was co-occurring with pipecolic acid, suggesting that the protective role of this species may be mediated by releasing pipecolic acid. Indoor relative humidity and the weight of vacuum dust were associated with AR and NAR, respectively (p < 0.05), but the health effects were mediated by two protective bacterial species, Aliinostoc morphoplasticum and Ilumatobacter fluminis. Overall, our study reported a similar microbial association pattern between AR and NAR and also revealed the complex interactions between microbial species, environmental characteristics, and rhinitis symptoms.
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| 27. |
- Fu, Xi, et al.
(författare)
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Associations between respiratory infections and bacterial microbiome in student dormitories in Northern China.
- 2020
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Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947 .- 1600-0668. ; 30:5, s. 816-826
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies reveal that the microbial diversity and composition in the respiratory tract are related to the susceptibility, development, and progression of respiratory infections. Indoor microorganisms can transmit into the respiratory tract through breathing, but their role in infections is unclear. Here, we present the first association study between the indoor microbiome and respiratory infections. In total, 357 students living in 86 dormitory rooms in Shanxi University were randomly selected to survey symptoms of infections. Settled air dust was collected to characterize bacterial compositions by 16S rRNA sequencing. The overall microbial richness was not associated with respiratory infections, but microorganisms from specific phylogenetic classes showed various associations. Taxa richness and abundance of Actinobacteria were protectively associated with infections (P < .05). The abundance of several genera in Gammaproteobacteria, including Haemophilus, Klebsiella, Buttiauxella, and Raoultella, was positively associated with infections (P < .005). The role of these microorganisms was consistent with previous human microbiota studies. Building age was associated with the overall microbial composition variation in dormitories and negatively associated with three potential risk genera in Proteobacteria (P < .05). The weight of vacuum dust was positively associated with a protective genus, Micrococcus in Actinobacteria (P < .05).
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| 28. |
- Fu, Xi, et al.
(författare)
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Associations between species-level indoor microbiome, environmental characteristics, and asthma in junior high schools of Terengganu, Malaysia
- 2022
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Ingår i: Air quality, atmosphere and health. - : Springer Nature. - 1873-9318 .- 1873-9326. ; 15:6, s. 1043-1055
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Tidskriftsartikel (refereegranskat)abstract
- Indoor microbiome exposure is important for asthma development, but current studies characterize the microbiome at the genus or above levels due to technical limitations. We aim to profile bacterial and fungal composition and concentration at the species level and assess its potential health effects. Four hundred sixty-three students from 8 junior high schools in Terengganu, Malaysia, were surveyed for asthma symptoms. Full-length PacBio amplicon sequencing and qPCR were conducted to quantify the absolute microbial concentration in the vacuum dust of the selected classroom. In total, 1358 bacterial and 358 fungal species were characterized, and drastic compositional variation was observed among classrooms. Three-level linear regression analyses revealed that taxa richness in Cyanobacteria were negatively associated with asthma (FDR < 0.001). The absolute concentration of Nocardioides exalbidus was protectively associated with asthma, and four bacteria species were positively associated with asthma (FDR < 0.1). Interestingly, all five species were recently isolated and characterized in Asian countries and never reported to associate with asthma. Indoor NO2 and formaldehyde concentration were associated with the overall bacterial community variation and fungal richness, respectively (p < 0.05). No environmental characteristics were directly associated with asthma, but indoor relative humidity, CO2 concentration, and weight of vacuum dust were associated with the asthma-related species (p < 0.05), suggesting a potential indirect health effect on students. This is the first study to characterize indoor microbiome and asthma-associated microorganisms at the species level, representing a region-specific microbiome exposure pattern in a tropical Asian country.
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| 29. |
- Fu, Xi, et al.
(författare)
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Associations between the indoor microbiome, environmental characteristics and respiratory infections in junior high school students of Johor Bahru, Malaysia.
- 2021
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Ingår i: Environmental Science. - : Royal Society of Chemistry. - 2050-7887 .- 2050-7895. ; 23:8, s. 1171-1181
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Tidskriftsartikel (refereegranskat)abstract
- Pathogens are commonly present in the human respiratory tract, but symptoms are varied among individuals. The interactions between pathogens, commensal microorganisms and host immune systems are important in shaping the susceptibility, development and severity of respiratory diseases. Compared to the extensive studies on the human microbiota, few studies reported the association between indoor microbiome exposure and respiratory infections. In this study, 308 students from 21 classrooms were randomly selected to survey the occurrence of respiratory infections in junior high schools of Johor Bahru, Malaysia. Vacuum dust was collected from the floor, chairs and desks of these classrooms, and high-throughput amplicon sequencing (16S rRNA and ITS) and quantitative PCR were conducted to characterize the absolute concentration of the indoor microorganisms. Fifteen bacterial genera in the classes Actinobacteria, Alphaproteobacteria, and Cyanobacteria were protectively associated with respiratory infections (p < 0.01), and these bacteria were mainly derived from the outdoor environment. Previous studies also reported that outdoor environmental bacteria were protectively associated with chronic respiratory diseases, such as asthma, but the genera identified were different between acute and chronic respiratory diseases. Four fungal genera from Ascomycota, including Devriesia, Endocarpon, Sarcinomyces and an unclassified genus from Herpotrichillaceae, were protectively associated with respiratory infections (p < 0.01). House dust mite (HDM) allergens and outdoor NO2 concentration were associated with respiratory infections and infection-related microorganisms. A causal mediation analysis revealed that the health effects of HDM and NO2 were partially or fully mediated by the indoor microorganisms. This is the first study to explore the association between environmental characteristics, microbiome exposure and respiratory infections in a public indoor environment, expanding our understanding of the complex interactions among these factors.
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| 30. |
- Fu, Xi, et al.
(författare)
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Classroom microbiome, functional pathways and sick-building syndrome (SBS) in urban and rural schools-Potential roles of indoor microbial amino acids and vitamin metabolites
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 795
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Tidskriftsartikel (refereegranskat)abstract
- Sick building symptoms (SBS) are defined as non-specific symptoms related to indoor exposures, including mucosal symptoms in eye, nose, throat, and skin, and general symptoms as headache and tiredness. Indoor microbial composition is associated with SBS symptoms, but the impact of microbial functional genes and potential metabolic products has not been characterized. We conducted a shotgun microbial metagenomic sequencing for vacuum dust collected in urban and rural schools in Shanxi province, China. SBS symptoms in students were surveyed, and microbial taxa and functional pathways related to the symptoms were identified using a multilevel linear regression model. SBS symptoms were common in students, and the prevalence of ocular and throat symptoms, headache, and tiredness was higher in urban than in rural areas (p < 0.05). A significant higher microbial alpha-diversity was found in rural areas than in urban areas (Chao1, p = 0.001; ACE, p = 0.002). Also, significant variation in microbial taxonomic and functional composition (beta-diversity) was observed between urban and rural areas (p < 0.005). Five potential risk Actinobacteria species were associated with SBS symptoms (p < 0.01); students in the classrooms with a higher abundance of an unclassified Geodermatophilaceae, Geodermatophilus, Fridmanniella luteola, Microlunatus phosphovorus and Mycetocola reported more nasal and throat symptoms and tiredness. Students with a higher abundance of an unclassified flavobacteriaceae reported fewer throat symptoms and tiredness. The abundance of microbial metabolic pathways related to the synthesis of B vitamins (biotin and folate), gamma-aminobutyric acid (GABA), short-chain fatty acids (SCFAs), and peptidoglycan and were protectively (negatively) associated with SBS symptoms (FDR < 0.05). The result is consistent with human microbiota studies, which reported that these microbial products are extensively involved in immunological processes and anti-inflammatory effects. This is the first study to report the functional potential of the indoor microbiome and the occurrence of SBS, providing new insights into the potential etiologic mechanisms in chronic inflammatory diseases.
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| 31. |
- Fu, Xi, et al.
(författare)
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Continental-Scale Microbiome Study Reveals Different Environmental Characteristics Determining Microbial Richness, Composition, and Quantity in Hotel Rooms
- 2020
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Ingår i: mSystems. - : AMER SOC MICROBIOLOGY. - 2379-5077. ; 5:3
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Tidskriftsartikel (refereegranskat)abstract
- Culture-independent microbiome surveys have been conducted in homes, hospitals, schools, kindergartens and vehicles for public transport, revealing diverse microbial distributions in built environments. However, microbiome composition and the associated environmental characteristics have not been characterized in hotel environments. We presented here the first continental-scale microbiome study of hotel rooms (n = 68) spanning Asia and Europe. Bacterial and fungal communities were described by amplicon sequencing of the 16S rRNA gene and internal transcribed spacer (ITS) region and quantitative PCR. Similar numbers of bacterial (4,344) and fungal (4,555) operational taxonomic units were identified in the same sequencing depth, but most fungal taxa showed a restricted distribution compared to bacterial taxa. Aerobic, ubiquitous bacteria dominated the hotel microbiome with compositional similarity to previous samples from building and human nasopharynx environments. The abundance of Aspergillus was negatively correlated with latitude and accounted for -80% of the total fungal load in seven low-latitude hotels. We calculated the association between hotel microbiome and 16 indoor and outdoor environmental characteristics. Fungal composition and absolute quantity showed concordant associations with the same environmental characteristics, including latitude, quality of the interior, proximity to the sea, and visible mold, while fungal richness was negatively associated with heavy traffic (95% confidence interval [CI] = -127.05 to -0.25) and wall-to-wall carpet (95% CI = -47.60 to -3.82). Bacterial compositional variation was associated with latitude, quality of the interior, and floor type, while bacterial richness was negatively associated with recent redecoration (95% CI -179.00 to -44.55) and mechanical ventilation (95% CI = -136.71 to -5.12). IMPORTANCE This is the first microbiome study to characterize the microbiome data and associated environmental characteristics in hotel environments. In this study, we found concordant variation between fungal compositional variation and absolute quantity and discordant variation between community variation/quantity and richness. Our study can be used to promote hotel hygiene standards and provide resource information for future microbiome and exposure studies associated with health effects in hotel rooms.
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| 32. |
- Fu, Xi, et al.
(författare)
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Derived habitats of indoor microbes are associated with asthma symptoms in Chinese university dormitories
- 2021
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Ingår i: Environmental Research. - : Elsevier. - 0013-9351 .- 1096-0953. ; 194
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Tidskriftsartikel (refereegranskat)abstract
- Increasing evidence from the home environment indicates that indoor microbiome exposure is associated with asthma development. However, indoor microbiome composition can be highly diverse and dynamic, and thus current studies fail to produce consistent results. Chinese university dormitories are special high-density dwellings with similar building and occupants characteristics, which facilitate to disentangle the complex interactions between microbes, environmental characteristics and asthma. Settled air dust and floor dust was collected from 87 dormitory rooms in Shanxi University. Bacterial communities were characterized by 16 S rRNA amplicon sequencing. Students (n = 357) were surveyed for asthma symptoms and measured for fractional exhaled nitric oxide (FeNO). Asthma was not associated with the overall bacterial richness but associated with specific phylogenetic classes. Taxa richness and abundance in Clostridia, including Ruminococcus, Blautia, Clostridium and Subdoligranulum, were positively associated with asthma (p < 0.05), and these taxa were mainly derived from the human gut. Taxa richness in Alphaproteobacteria and Actinobacteria were marginally protectively associated with asthma, and these taxa were mainly derived from the outdoor environment. Bacterial richness and abundance were not associated with FeNO levels. Building age was associated with overall bacterial community variation in air and floor dust (p < 0.05), but not associated with the asthma-related microorganisms. Our data shows that taxa from different phylogenetic classes and derived habitats have different health effects, indicating the importance of incorporating phylogenetic and ecological concepts in revealing patterns in the microbiome asthma association analysis.
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| 33. |
- Fu, Xi, et al.
(författare)
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Indoor bacterial, fungal and viral species and functional genes in urban and rural schools in Shanxi Province, China : association with asthma, rhinitis and rhinoconjunctivitis in high school students
- 2021
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Ingår i: Microbiome. - : Springer Nature. - 2049-2618. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundStudies in developed countries have reported that the prevalence of asthma and rhinitis is higher in urban areas than in rural areas, and this phenomenon is associated with urbanization and changing indoor microbiome exposure. Developing countries such as China have experienced rapid urbanization in past years, but no study has investigated microbiome exposure and urban-rural health effects in these countries.MethodsNine high schools from urban and rural areas were randomly selected in Shanxi Province, China, and classroom vacuum dust was collected for shotgun metagenomic sequencing. A self-administered questionnaire was collected from 1332 students for personal information and health data. Three-level logistic regression was performed between microbial richness/abundance/functional pathways and the occurrence of asthma and rhinitis symptoms.ResultsConsistent with developed countries, the prevalence of wheeze and rhinitis was higher in urban areas than in rural areas (p < 0.05). Metagenomic profiling revealed 8302 bacterial, 395 archaeal, 744 fungal, 524 protist and 1103 viral species in classroom dust. Actinobacteria (mean relative abundance 49.7%), Gammaproteobacteria (18.4%) and Alphaproteobacteria (10.0%) were the most abundant bacterial classes. The overall microbiome composition was significantly different between urban and rural schools (p = 0.001, Adonis). Species from Betaproteobactera, Gammaproteobacteria and Bacilli were enriched in urban schools, and species from Actinobacteria and Cyanobacteria were enriched in rural schools. Potential pathogens were present in higher abundance in urban schools than in rural schools (p < 0.05). Pseudoalteromonas, Neospora caninum and Microbacterium foliorum were positively associated with the occurrence of wheeze, rhinitis and rhinoconjunctivitis, and Brachybacterium was protectively (negatively) associated with rhinitis (p < 0.01). The abundance of human endocrine and metabolic disease pathways was positively associated with rhinitis (p = 0.008), and butyrate and propionate metabolic genes and pathways were significantly enriched in rural schools (p < 0.005), in line with previous findings that these short-chain fatty acids protect against inflammatory diseases in the human gut.ConclusionsWe conducted the first indoor microbiome survey in urban/rural environments with shotgun metagenomics, and the results revealed high-resolution microbial taxonomic and functional profiling and potential health effects.
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| 34. |
- Fu, Xi, et al.
(författare)
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Indoor microbiome, environmental characteristics and asthma among junior high school students in Johor Bahru, Malaysia
- 2020
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 138
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Tidskriftsartikel (refereegranskat)abstract
- Indoor microbial diversity and composition are suggested to affect the prevalence and severity of asthma by previous home microbiome studies, but no microbiome-health association study has been conducted in a school environment, especially in tropical countries. In this study, we collected floor dust and environmental characteristics from 21 classrooms, and health data related to asthma symptoms from 309 students, in junior high schools in Johor Bahru, Malaysia. The bacterial and fungal composition was characterized by sequencing 16s rRNA gene and internal transcribed spacer (ITS) region, and the absolute microbial concentration was quantified by qPCR. In total, 326 bacterial and 255 fungal genera were characterized. Five bacterial (Sphingobium, Rhodomicrobium, Shimwellia, Solirubrobacter, Pleurocapsa) and two fungal (Torulaspora and Leptosphaeriaceae) taxa were protective for asthma severity. Two bacterial taxa, Izhakiella and Robinsoniella, were positively associated with asthma severity. Several protective bacterial taxa including Rhodomicrobium, Shimwellia and Sphingobium have been reported as protective microbes in previous studies, whereas other taxa were first time reported. Environmental characteristics, such as age of building, size of textile curtain per room volume, occurrence of cockroaches, concentration of house dust mite allergens transferred from homes by the occupants, were involved in shaping the overall microbial community but not asthma-associated taxa; whereas visible dampness and mold, which did not change the overall microbial community for floor dust, was negatively associated with the concentration of protective bacteria Rhodomicrobium (beta =-2.86, p = 0.021) of asthma. The result indicates complex interactions between microbes, environmental characteristics and asthma symptoms. Overall, this is the first indoor microbiome study to characterize the asthma-associated microbes and their environmental determinant in the tropical area, promoting the understanding of microbial exposure and respiratory health in this region.
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| 35. |
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| 36. |
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| 37. |
- Granskog, Viktor, et al.
(författare)
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Linear Dendritic Block Copolymers as Promising Biomaterials for the Manufacturing of Soft Tissue Adhesive Patches Using Visible Light Initiated Thiol-Ene Coupling Chemistry
- 2015
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Ingår i: Advanced Functional Materials. - : Wiley-VCH Verlagsgesellschaft. - 1616-301X .- 1616-3028. ; 25:42, s. 6596-6605
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Tidskriftsartikel (refereegranskat)abstract
- A library of dendritic-linear-dendritic (DLD) materials comprising linear poly(ethylene glycol) and hyperbranched dendritic blocks based on 2,2-bis(hydroxymethyl) propionic acid is successfully synthesized and post-functionalized with peripheral allyl groups. Reactive DLDs with pseudo-generations of 3 to 6 (G3-G6) are isolated in large scale allowing their thorough evaluation as important components for the development of biomedical adhesives. Due to their branched nature and inherent degradable ester-bonds, promising biomaterial resins are accomplished with suitable viscosity, eliminating the excessive use of co-solvents. By utilizing benign high-energy visible light initiated thiol-ene coupling chemistry, DLDs together with tris[2-(3-mercaptopropionyloxy) ethyl] isocyanurate and surgical mesh enable the fabrication of soft tissue adhesive patches (STAPs) within a total irradiation time of 30 s. The STAPs display the ability to create good adhesion to wet soft tissue and encouraging results in cytotoxicity tests. All crosslinked materials are also found to degrade after being stored in human blood plasma and phosphate buffered saline. The proposed benign methodology coupled with the promising features of the crosslinked materials is herein envisioned as a soft tissue adhesive with properties that do not exist in currently available tissue adhesives.
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| 38. |
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| 39. |
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| 40. |
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| 41. |
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| 42. |
- Krasilnikov, A., et al.
(författare)
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Evidence of 9 Be + p nuclear reactions during 2ω CH and hydrogen minority ICRH in JET-ILW hydrogen and deuterium plasmas
- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:2
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Tidskriftsartikel (refereegranskat)abstract
- The intensity of 9Be + p nuclear fusion reactions was experimentally studied during second harmonic (2ω CH) ion-cyclotron resonance heating (ICRH) and further analyzed during fundamental hydrogen minority ICRH of JET-ILW hydrogen and deuterium plasmas. In relatively low-density plasmas with a high ICRH power, a population of fast H+ ions was created and measured by neutral particle analyzers. Primary and secondary nuclear reaction products, due to 9Be + p interaction, were observed with fast ion loss detectors, γ-ray spectrometers and neutron flux monitors and spectrometers. The possibility of using 9Be(p, d)2α and 9Be(p, α)6Li nuclear reactions to create a population of fast alpha particles and study their behaviour in non-active stage of ITER operation is discussed in the paper.
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| 43. |
- Li, Cong, et al.
(författare)
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Advanced multimodal imaging in differentiating glioma recurrence from post-radiotherapy changes
- 2020
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Ingår i: Novel therapeutic advances in glioblastoma. - LONDON ENGLAND : Elsevier. - 9780128211144 ; , s. 281-297
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Bokkapitel (refereegranskat)abstract
- Gliomas are the most common malignant primary brain tumor, and their prognosis is extremely poor. Radiotherapy is an important treatment for glioma patients, but the changes caused by radiotherapy have brought difficulties in clinical image evaluation because differentiating glioma recurrence from post-radiotherapy changes including pseudo-progression (PD) and radiation necrosis (RN) remains a challenge. Therefore, accurate and reliable imaging evaluation is very important for making clinical decisions. In recent years, advanced multimodal imaging techniques have been applied to achieve the goal of better differentiating glioma recurrence from post-radiotherapy changes for minimizing errors associated with interpretation of treatment effects. In this review, we discuss the recent applications of advanced multimodal imaging such as diffusion MRI sequences, amide proton transfer MRI sequences, perfusion MRI sequences, MR spectroscopy and multinuclides PET/CT in the evaluation of post-radiotherapy treatment response in glioma patients and highlight their potential role in differentiating post-radiotherapy changes from glioma recurrence.
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| 44. |
- Li, Cuiyan, et al.
(författare)
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Photocatalytic and antibacterial properties of Au-decorated Fe3O4@mTiO(2) core-shell microspheres
- 2014
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Ingår i: Applied Catalysis B. - : Elsevier BV. - 0926-3373 .- 1873-3883. ; 156, s. 314-322
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Tidskriftsartikel (refereegranskat)abstract
- A facile approach for the fabrication of Au-decorated mesoporous Fe3O4@TiO2 (Fe3O4@mTiO(2)) core-shell microspheres is demonstrated. The protocol involved the coating of a successive layer of TiO2 onto a magnetic Fe3O4 core via a sol-gel process, followed by TiO2 crystallization and mesopore-formation by a hydrothermal treatment, and then the deposition of Au nanoparticles onto Fe3O4@mTiO(2) microspheres through an in situ reduction of perchloric acid. The mesoporous microspheres (Fe3O4@mTiO(2)) showed stronger magnetic properties than the dense sample (Fe3O4@TiO2) before the hydrothermal treatment. The size and loading amount of Au nanoparticles were controlled by the reduction temperature and concentration of Au salt, respectively. Compared to unmodified Fe3O4@mTiO(2) microspheres, Fe3O4@mTiO(2)@Au microspheres showed higher photocatalytic activity for organic degradation and antibacterial action in water. These core-shell Fe3O4@mTiO(2)@Au microspheres can serve as efficient and recyclable photocatalysts, which have promising applications in environmental treatment.
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| 45. |
- Li, Cuiyan, et al.
(författare)
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Polyacrylamide-metal nanocomposites : one-pot synthesis, antibacterial properties, and thermal stability
- 2013
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Ingår i: Journal of nanoparticle research. - : Springer Science and Business Media LLC. - 1388-0764 .- 1572-896X. ; 15:9, s. UNSP 1922-
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Tidskriftsartikel (refereegranskat)abstract
- The incorporation of inorganic nanoparticles into polymers is a hot research spot, since it endows the nanocomposites with new or improved properties by exploiting synergistic effects. Here we report a facile one-pot synthesis of polyacrylamide (PAM)-metal (M = Au, Ag, or Pd) nanocomposites in ethylene glycol (EG). The simultaneous polymerization of the acylamide (AM) monomer and formation of metal nanoparticles lead to a homogeneous distribution of metal nanoparticles in the PAM matrix. The sizes of Au, Ag, and Pd nanoparticles are 55.50 +/- 10.6, 14.15 +/- 2.57, and 7.74 +/- 1.82 nm, respectively. The reaction system only includes EG, AM monomer, and corresponding metal salt. EG acts as both the solvent and the reducing reagent. Also, no initiator for AM polymerization and no surfactant for stabilization of metal nanoparticles are used. Furthermore, this simple synthetic route does not rely on any special or expensive equipment, thus can be exploited to the synthesis of similar polymer-inorganic nanocomposites. Compared to PAM, the PAM-metal nanocomposites showed enhanced thermal stability and antibacterial properties.
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| 46. |
- Li, Jie, et al.
(författare)
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Parentheses used as pragmatic strategies in Chinese online socialization
- 2023
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Ingår i: Pragmatics and Society. - : John Benjamins Publishing Company. - 1878-9714 .- 1878-9722. ; 14:3, s. 442-460
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Tidskriftsartikel (refereegranskat)abstract
- This paper details the use of parentheses as pragmatic strategies in Chinese network socialization. The data were collected from Weibo, Wechat, QQ and other online social platforms, and analyzed from the perspective of Cyberpragmatics. We consider the pragmatic features and functions of parentheses as an indivisible part of the whole unit in relation to emojis or graphicons. As pragmatic strategies, parentheses aid speakers in indirectly performing various pragmatic intentions, like adding supplementary information to the interaction, isolating different topics, and contrasting content between the text outside and within parentheses. Further pragmatic functions realized by parentheses include indirectly conveying intention, relieving communicative awkwardness and adjusting interlocutors expectations. We conclude that using parentheses as pragmatic strategies in network socialization is the result of the evolution of the Internet language, and varies from the use of other emojis, which directly convey intentions and meaning.
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| 47. |
- Li, Qian, et al.
(författare)
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Multiple biomarker responses in caged benthic gastropods Bellamya aeruginosa after in situ exposure to Taihu Lake in China
- 2018
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Ingår i: Environmental Sciences Europe. - : Springer Science and Business Media LLC. - 2190-4707 .- 2190-4715. ; 30
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Tidskriftsartikel (refereegranskat)abstract
- Background: Freshwater sediments have been recognized as a long-term sink and potential source for environmental pollutants released into the aquatic ecosystems. In this study, the sediment quality of Taihu Lake, which is susceptible to anthropogenic contamination, was assessed by a combination of chemical analytical and biological end points. Specifically, the snail Bellamya aeruginosa was caged in situ at two locations representing different pollution levels for different exposure times (7, 14 and 21 days). At each of these time points, biochemical parameters, i.e., phase I biotransformation enzymes ethoxyresorufin-O-deethylase (EROD), the antioxidant enzymes superoxide dismutase and catalase, reactive oxygen species, protein carbonyl content and lipid peroxidation, were evaluated in the hepato-pancreas of snails. In addition, surface sediments were collected for analysis of contaminants of concern, including inorganic pollutants, organochlorine pesticides, polychlorinated biphenyls and polybrominated diphenyl ethers.Results: Chemical analyses revealed that sediments from Taihu Lake were contaminated with trace elements and organic pollutants. Concentrations of trace elements (Cu, Ni and As) and organochlorinated pesticides (4,4'-DDE) exceeded their corresponding threshold effect level according to the sediment quality assessment values for freshwater ecosystems in Canada, indicating that adverse biological effects may occur. All biomarkers, except EROD activity, were induced in snails during all exposure times. The integrated biomarker response index (IBR) indicated that during the initial exposure phase (7 days), B. aeruginosa were subjected to significant environmental stress, which diminished during later sampling time points.Conclusions: Results showed that IBR correlated well with the levels of environmental contaminants, demonstrating the applicability of this biomonitoring approach to complex environmental exposure scenarios.
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| 48. |
- Li, Yanling, 1990, et al.
(författare)
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Evaluation of temperature controlled oedometer test apparatus
- 2016
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Ingår i: Energy Geotechnics. - : CRC Press. - 9781138032996 ; , s. 623-627
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Konferensbidrag (refereegranskat)abstract
- Internationally, geothermal foundations have started to become more common, and their thermal efficiency is being improved. In Sweden, however, energy piles have not been widely used. This is mainly due to the remaining uncertainties in the effect of the thermal cycles on the soft soil response. Under repeated generation and dissipation of excess pore pressures, the microstructure and consequently mechanical properties of soft soils, especially of sensitive (quick) clays that are common in Sweden are significantly alerted. Temperature controlled laboratory tests are required to study the thermal response of soft sensitive clay. This paper introduces a modified oedometer apparatus for the investigation of the temperature dependence of the mechanical properties of clay, with special focus on the creep rate of sensitive clay. © 2016 Taylor & Francis Group, London.
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| 49. |
- Li, Yanling, 1990
(författare)
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On the impact of temperature perturbations on the creep of sensitive clay
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Temperature affects the soil response, but is not fully understood and quantified and thus often ignored. The temperature fluctuations resulting from energy foundations and construction activities, such as excavations and soil stabilization, however, may lead to changes in the hydromechanical response of the clay. Especially, the sensitive clays that are abundant in Scandinavia, may be detrimentally affected. The fragile natural bonds between the clay platelets of sensitive clays are prone to disturbances from environmental changes, including temperature perturbations. The change in hydro-mechanical properties, such as the compressibility and the creep-rate, can affect the long-term stability of the geothermal structures. The aim of the Thesis is to study the impact of temperature perturbations on the creep of sensitive clay. A systematic series of temperature-controlled laboratory tests (5 to 25 ◦C), including oedometer tests with static and cyclic thermal loading steps, has been carried out on natural and remoulded samples of natural sensitive clay from the Utby test-site in Gothenburg, Sweden. An original time-saving test protocol is developed to obtain sufficient data within the duration of the project. The results demonstrate that the influence of the temperature on the creep rate of sensitive clays depends on the amount of natural bonding. Heating increments lead to larger changes in creep rate than cooling decrements. The thermal loading cycles lead to larger permanent strains when compared to the static heating and cooling paths. Thorough analyses of the results using the temperature-invariant rate-dependent model implemented in a multi-physics numerical framework indicates that the temperature dependency can be uniquely linked to the amount of natural bonding in the clay sample. Consequently, the temperature-invariant model is modified by correlating the apparent preconsolidation pressure with temperature and the amount of natural bonding in the clay samples. The temperature-dependent model, Creep-SCLAY1ST, improves the predictions of the mechanical response under static thermal loading considerably, whilst the modelling of the cyclic loading paths proved to be somewhat unsatisfactory. The latter is not a shortcoming of the proposed model modification, rather an intrinsic limitation of the underlying temperature-invariant model.
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| 50. |
- Li, Yuanzi, et al.
(författare)
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Optimization of the l-tyrosine metabolic pathway in Saccharomyces cerevisiae by analyzing p-coumaric acid production
- 2020
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Ingår i: 3 Biotech. - : Springer Science and Business Media LLC. - 2190-572X .- 2190-5738. ; 10:6
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we applied a series of genetic modifications to wild-type S. cerevisiae strain BY4741 to address the bottlenecks in the l-tyrosine pathway. A tyrosine ammonia-lyase (TAL) gene from Rhodobacter capsulatus, which can catalyze conversion of l-tyrosine into p-coumaric acid, was overexpressed to facilitate the analysis of l-tyrosine and test the strain's capability to synthesize heterologous derivatives. First, we enhanced the supply of precursors by overexpressing transaldolase gene TAL1, enolase II gene ENO2, and pentafunctional enzyme gene ARO1 resulting in a 1.55-fold increase in p-coumaric acid production. Second, feedback inhibition of 3-deoxy-d-arabino-heptulosonate-7-phosphate synthase and chorismate mutase was relieved by overexpressing the mutated feedback-resistant ARO4(K229L) and ARO7(G141S), and a 3.61-fold improvement of p-coumaric acid production was obtained. Finally, formation of byproducts was decreased by deleting pyruvate decarboxylase gene PDC5 and phenylpyruvate decarboxylase gene ARO10, and p-coumaric acid production was increased 2.52-fold. The best producer-when TAL1, ENO2, ARO1, ARO4(K229L), ARO7(G141S), and TAL were overexpressed, and PDC5 and ARO10 were deleted-increased p-coumaric acid production by 14.08-fold (from 1.4 to 19.71 mg L-1). Our study provided a valuable insight into the optimization of l-tyrosine metabolic pathway.
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