| 1. |
- Guan, Ruicong, et al.
(författare)
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Dexmedetomidine alleviates oxygen and glucose deprivation-induced apoptosis in mesenchymal stem cell via downregulation of MKP-1
- 2022
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Ingår i: Biocell (Mendoza). - : Tech Science Press. - 0327-9545 .- 1667-5746. ; 46:11, s. 2455-2463
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Tidskriftsartikel (refereegranskat)abstract
- Bone marrow mesenchymal stem cell (MSC)-based therapy is a novel candidate for heart repair. But ischemia-reperfusion injury leads to low viability of MSC. Dexmedetomidine (Dex) has been found to protect neurons against ischemia-reperfusion injury. It remains unknown if Dex could increase the viability of MSCs under ischemia. The present study is to observe the potential protective effect of Dex on MSCs under ischemia and its underlying mechanisms. Specific mRNAs related to myocardial ischemia in the GEO database were selected from the mRNA profiles assessed in a previous study using microarray. The most dysregulated mRNAs of the specific ones from the above study were subject to bioinformatics analysis at our laboratory. These dysregulated mRNAs possibly regulated apoptosis of cardiomyocytes and were validated in vitro for their protective effect on MSCs under ischemia. MSCs were pre-treated with Dex at 10 mu M concentration for 24 h under oxygen-glucose deprivation (OGD). Flow cytometry and TUNEL assay were carried out to detect apoptosis in Dex-pretreated MSCs under OGD. The relative expressions of mitogen-activated protein kinase phosphatase 1 (MKP-1) and related genes were detected by quantitative polymerase chain reaction and western blotting. Microarray data analysis revealed that Dex regulates MAPK phosphatase activity. Dex significantly reduced in vitro apoptosis of MSCs under OGD, which suppressed the synthesis level of Beclin1 and light chain 3 proteins. Dex down-regulated MKP-1 expression and attenuated an OGD-induced change in the mitogen activated protein kinase 3 (MAPK3) signaling pathway. Dex increases the viability of MSC and improves its tolerance to OGD in association with the MKP-1 signaling pathway, thus suggesting the potential of Dex as a novel strategy for promoting MSCs efficacy under ischemia.
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| 2. |
- Li, Jingwen, et al.
(författare)
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Emerging Food Packaging Applications of Cellulose Nanocomposites : A Review
- 2022
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 14:19
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Forskningsöversikt (refereegranskat)abstract
- Cellulose is the most abundant biopolymer on Earth, which is synthesized by plants, bacteria, and animals, with source-dependent properties. Cellulose containing beta-1,4-linked D-glucoses further assembles into hierarchical structures in microfibrils, which can be processed to nanocellulose with length or width in the nanoscale after a variety of pretreatments including enzymatic hydrolysis, TEMPO-oxidation, and carboxymethylation. Nanocellulose can be mainly categorized into cellulose nanocrystal (CNC) produced by acid hydrolysis, cellulose nanofibrils (CNF) prepared by refining, homogenization, microfluidization, sonification, ball milling, and the aqueous counter collision (ACC) method, and bacterial cellulose (BC) biosynthesized by the Acetobacter species. Due to nontoxicity, good biodegradability and biocompatibility, high aspect ratio, low thermal expansion coefficient, excellent mechanical strength, and unique optical properties, nanocellulose is utilized to develop various cellulose nanocomposites through solution casting, Layer-by-Layer (LBL) assembly, extrusion, coating, gel-forming, spray drying, electrostatic spinning, adsorption, nanoemulsion, and other techniques, and has been widely used as food packaging material with excellent barrier and mechanical properties, antibacterial activity, and stimuli-responsive performance to improve the food quality and shelf life. Under the driving force of the increasing green food packaging market, nanocellulose production has gradually developed from lab-scale to pilot- or even industrial-scale, mainly in Europe, Africa, and Asia, though developing cost-effective preparation techniques and precisely tuning the physicochemical properties are key to the commercialization. We expect this review to summarise the recent literature in the nanocellulose-based food packaging field and provide the readers with the state-of-the-art of this research area.
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| 3. |
- Yu, Wenjin, et al.
(författare)
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Deep Learning-Based Classification of Cancer Cell in Leptomeningeal Metastasis on Cytomorphologic Features of Cerebrospinal Fluid
- 2022
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Ingår i: Frontiers in Oncology. - : Frontiers Media SA. - 2234-943X. ; 12, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- Background: It is a critical challenge to diagnose leptomeningeal metastasis (LM), given its technical difficulty and the lack of typical symptoms. The existing gold standard of diagnosing LM is to use positive cerebrospinal fluid (CSF) cytology, which consumes significantly more time to classify cells under a microscope.Objective: This study aims to establish a deep learning model to classify cancer cells in CSF, thus facilitating doctors to achieve an accurate and fast diagnosis of LM in an early stage.Method: The cerebrospinal fluid laboratory of Xijing Hospital provides 53,255 cells from 90 LM patients in the research. We used two deep convolutional neural networks (CNN) models to classify cells in the CSF. A five-way cell classification model (CNN1) consists of lymphocytes, monocytes, neutrophils, erythrocytes, and cancer cells. A four-way cancer cell classification model (CNN2) consists of lung cancer cells, gastric cancer cells, breast cancer cells, and pancreatic cancer cells. Here, the CNN models were constructed by Resnet-inception-V2. We evaluated the performance of the proposed models on two external datasets and compared them with the results from 42 doctors of various levels of experience in the human-machine tests. Furthermore, we develop a computer-aided diagnosis (CAD) software to generate cytology diagnosis reports in the research rapidly.Results: With respect to the validation set, the mean average precision (mAP) of CNN1 is over 95% and that of CNN2 is close to 80%. Hence, the proposed deep learning model effectively classifies cells in CSF to facilitate the screening of cancer cells. In the human-machine tests, the accuracy of CNN1 is similar to the results from experts, with higher accuracy than doctors in other levels. Moreover, the overall accuracy of CNN2 is 10% higher than that of experts, with a time consumption of only one-third of that consumed by an expert. Using the CAD software saves 90% working time of cytologists.Conclusion: A deep learning method has been developed to assist the LM diagnosis with high accuracy and low time consumption effectively. Thanks to labeled data and step-by-step training, our proposed method can successfully classify cancer cells in the CSF to assist LM diagnosis early. In addition, this unique research can predict cancer’s primary source of LM, which relies on cytomorphologic features without immunohistochemistry. Our results show that deep learning can be widely used in medical images to classify cerebrospinal fluid cells. For complex cancer classification tasks, the accuracy of the proposed method is significantly higher than that of specialist doctors, and its performance is better than that of junior doctors and interns. The application of CNNs and CAD software may ultimately aid in expediting the diagnosis and overcoming the shortage of experienced cytologists, thereby facilitating earlier treatment and improving the prognosis of LM.
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| 4. |
- Diesend, Jan, et al.
(författare)
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Fractional 2 '-O-methylation in the ribosomal RNA of Dictyostelium discoideum supports ribosome heterogeneity in Amoebozoa
- 2022
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- A hallmark of ribosomal RNA (rRNA) are 2 '-O-methyl groups that are introduced sequence specifically by box C/D small nucleolar RNAs (snoRNAs) in ribonucleoprotein particles. Most data on this chemical modification and its impact on RNA folding and stability are derived from organisms of the Opisthokonta supergroup. Using bioinformatics and RNA-seq data, we identify 30 novel box C/D snoRNAs in Dictyostelium discoideum, many of which are differentially expressed during the multicellular development of the amoeba. By applying RiboMeth-seq, we find 49 positions in the 17S and 26S rRNA 2 '-O-methylated. Several of these nucleotides are substoichiometrically modified, with one displaying dynamic modification levels during development. Using homology-based models for the D. discoideum rRNA secondary structures, we localize many modified nucleotides in the vicinity of the ribosomal A, P and E sites. For most modified positions, a guiding box C/D snoRNA could be identified, allowing to determine idiosyncratic features of the snoRNA/rRNA interactions in the amoeba. Our data from D. discoideum represents the first evidence for ribosome heterogeneity in the Amoebozoa supergroup, allowing to suggest that it is a common feature of all eukaryotes.
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| 5. |
- Du, J., et al.
(författare)
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Aberrant elevated microRNA-146a in dendritic cells (DC) induced by human pancreatic cancer cell line BxPC-3-conditioned medium inhibits DC maturation and activation
- 2012
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Ingår i: Medical Oncology. - : Springer Science and Business Media LLC. - 1357-0560 .- 1559-131X. ; 29:4, s. 2814-2823
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Tidskriftsartikel (refereegranskat)abstract
- It has been shown that the function of dendritic cell (DC) is suppressed in pancreatic cancer patients; however, the detailed mechanism involved in it remains unclear. Here, we used medium conditioned by a highly metastatic human pancreatic cancer cell line BxPC-3 [BxPC-3-conditioned medium (BxCM)] to culture human CD14 + monocyte-derived DCs in vitro. Both DC differentiation and antigen presentation function were inhibited by BxCM. The microRNA-146a (miRNA-146a) expression is aberrantly up-regulated in BxCM-treated DCs. In addition, inhibition of aberrant miRNA-146a expression partly rescues the BxCM-induced defects in differentiation and function of DCs, which may be through regulation of Smad4 expression. Taken together, our findings indicate that aberrant miRNA-146a expression is one of main factors responsible for inhibition of DC maturation and antigen presentation function, and this inhibitory effect on DCs may be due to the repression of Smad4 mediated signal pathway by BxCM.
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| 6. |
- Guan, Ruicong, et al.
(författare)
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Plasma Exosome miRNAs Profile in Patients With ST-Segment Elevation Myocardial Infarction
- 2022
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Ingår i: Frontiers in Cardiovascular Medicine. - : Frontiers Media SA. - 2297-055X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundCirculating microRNAs (miRNAs) have been found to have different expressions in different phases of acute myocardial infarction. The profiles of plasma exosome miRNAs in patients with ST-segment elevation myocardial infarction (STEMI) at 3-6 months postinfarction are unknown. ObjectiveThe aim of this study was to assess the profiles of plasma exosome miRNAs in patients with STEMI in comparison with healthy volunteers and to select specific exosome miRNAs related to pathophysiological changes post-STEMI. MethodsPlasma and echocardiography parameters were collected from 30 patients 3-6 months after STEMI and 30 healthy volunteers. Plasma exosome miRNAs were assessed by using high-throughput sequence (Illumina HiSeq 2500) and profile of the plasma exosome miRNAs was established in 10 patients and 6 healthy volunteers. The specific exosome miRNAs related to heart diseases were selected according to the TargetScan database. The specificity of the selected exosome miRNAs was evaluated in additional 20 post-STEMI patients and 24 healthy volunteers by using quantitative PCR (qPCR). Left ventricular remodeling (LVR) was defined using the European Association of Cardiovascular Imaging criteria according to echocardiography examination. Correlations between expression of the specific miRNAs and echocardiography parameters of LVR were assessed using the Spearman correlation analysis. ResultsTwenty eight upregulated miRNAs and 49 downregulated miRNAs were found in patients 3-6 months after STEMI (p < 0.01) in comparison with the healthy volunteers. The two least expressed and heart-related exosome miRNAs were hsa-miR-181a-3p (0.64-fold, p < 0.01) and hsa-miR-874-3p (0.50-fold, p < 0.01), which were further confirmed by using qPCR and demonstrated significant specificity in another 20 patients with post-STEMI comparing to 24 healthy volunteers [area under the curve (AUC) = 0.68, p < 0.05; AUC = 0.74, p < 0.05]. The expression of hsa-miR-181a-3p was downregulated in patients with LV adverse remodeling in comparison with patients without LV adverse remodeling and healthy volunteers. ConclusionCirculating exosome miR-874-3p and miR-181a-3p were downregulated in patients with STEMI postinfarction. Exosome hsa-miR-181a-3p might play a potential role in the development of LVR in patients with post-STEMI.
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| 7. |
- Hon, Marc, et al.
(författare)
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A close-in giant planet escapes engulfment by its star
- 2023
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Ingår i: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 618:7967, s. 917-920
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Tidskriftsartikel (refereegranskat)abstract
- When main-sequence stars expand into red giants, they are expected to engulf close-in planets(1-5). Until now, the absence of planets with short orbital periods around post-expansion, core-helium-burning red giants(6-8) has been interpreted as evidence that short-period planets around Sun-like stars do not survive the giant expansion phase of their host stars(9). Here we present the discovery that the giant planet 8 Ursae Minoris b(10) orbits a core-helium-burning red giant. At a distance of only 0.5 au from its host star, the planet would have been engulfed by its host star, which is predicted by standard single-star evolution to have previously expanded to a radius of 0.7 au. Given the brief lifetime of helium-burning giants, the nearly circular orbit of the planet is challenging to reconcile with scenarios in which the planet survives by having a distant orbit initially. Instead, the planet may have avoided engulfment through a stellar merger that either altered the evolution of the host star or produced 8 Ursae Minoris b as a second-generation planet(11). This system shows that core-helium-burning red giants can harbour close planets and provides evidence for the role of non-canonical stellar evolution in the extended survival of late-stage exoplanetary systems.
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| 8. |
- Huo, Jingwen, et al.
(författare)
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Drivers of fluctuating embodied carbon emissions in international services trade
- 2021
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Ingår i: One Earth. - : ELSEVIER. - 2590-3330 .- 2590-3322. ; 4:9, s. 1322-1332
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Tidskriftsartikel (refereegranskat)abstract
- Service industries are generally considered "green'' because of their marginal direct emissions; however, they account for 65% of the world gross domestic product and over 20% of total global trade in 2019. Here, we quantify the evolution of carbon emissions embodied in services trade from 2010 to 2018 and identify the driving factors of emission change at the global and regional scales. The annual growth rate of embodied emissions exported from the Global South (2.0%) is double that of the Global North (1.0%), with a different trade structure. We further identify three trade patterns of service export in the Global South based on the bilateral trade partnership and annual growth rate. Three kinds of specific emission mitigation policies are proposed based on the characters of services trade and different trade structures between different regions. The results provide quantitative evidence currently lacking and critical to policy decision making.
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| 9. |
- Li, Jingwen, et al.
(författare)
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Nisin electroadsorption-enabled multifunctional bacterial cellulose membranes for highly efficient removal of organic and microbial pollutants in water
- 2022
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 440, s. 135922-
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Tidskriftsartikel (refereegranskat)abstract
- Membranes fabricated from bacteria-produced cellulose have many practical and technological advantages over other means of cellulose fiber production, however, their functionality for targeted applications is limited and requires complex, multi-stage processing, while the mechanisms underpinned the optimum improvements remain largely unknown. Focusing on one of the highest-demand applications in wastewater treatment, here we resolve the three persistent issues in bacterial cellulose membranes (BCMs), namely poor fibrillar network quality, insufficient functionality and unsatisfactory performance, and discover the counterintuitive, yet most effective mechanism of imparting the multifunctional properties. First, innovative application of the Hestrin-Shramm medium instead of the CM0986 medium stimulated Taonella mepensis to produce BCMs with higher yields, more uniform fibrils and developed fibrillar networks, higher crystallinity indexes, better mechanical and thermal properties. Second, a novel but facile electroadsorption method was developed to enhance BCM functionality via bonding a natural bactericidal peptide-Nisin to the deliberately activated terminals on the BCM surface, achieving great antibacterial activity, good durability, well-preserved nanoporous network, outstanding water retention and low toxicity. Third, due to the synergetic effects of surface adsorption, ionic bonding, physical retention and active microbial killing, the Nisin-decorated BCMs enabled outstanding organic dye removal and excellent disinfection performance, among the best in the available reports. Collectively, this study demonstrates that electroadsorption is a promising and potentially generic strategy to fabricate Nisin-decorated and functionalized BCMs for next-generation membrane filters toward water purification.
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| 10. |
- Li, Yuchen, et al.
(författare)
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Psychological distress among health professional students during the COVID-19 outbreak
- 2021
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Ingår i: Psychological Medicine. - : Cambridge University Press. - 0033-2917 .- 1469-8978. ; 51:11, s. 1952-1954
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Tidskriftsartikel (refereegranskat)abstract
- Background: Due to the drastic surge of COVID-19 patients, many countries are considering or already graduating health professional students early to aid professional resources. We aimed to assess outbreak-related psychological distress and symptoms of acute stress reaction (ASR) in health professional students and to characterize individuals with potential need for interventions.Methods: We conducted a prospective cohort study of 1442 health professional students at Sichuan University, China. At baseline (October 2019), participants were assessed for childhood adversity, stressful life events, internet addiction, and family functioning. Using multivariable logistic regression, we examined associations of the above exposures with subsequent psychological distress and ASR in response to the outbreak.Results: Three hundred and eighty-four (26.63%) participants demonstrated clinically significant psychological distress, while 160 (11.10%) met the criterion for a probable ASR. Individuals who scored high on both childhood adversity and stressful life event experiences during the past year were at increased risks of both distress (ORs 2.00-2.66) and probable ASR (ORs 2.23-3.10), respectively. Moreover, internet addiction was associated with elevated risks of distress (OR 2.05, 95% CI 1.60-2.64) and probable ASR (OR 2.15, 95% CI 1.50-3.10). By contrast, good family functioning was associated with decreased risks of distress (OR 0.43, 95% CI 0.33-0.55) and probable ASR (OR 0.48, 95% CI 0.33-0.69). All associations were independent of baseline psychological distress.Conclusions: Our findings suggest that COVID-19 related psychological distress and high symptoms burden of ASR are common among health professional students. Extended family and professional support should be considered for vulnerable individuals during these unprecedented times.
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| 11. |
- Lin, Zhaowei, et al.
(författare)
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Effects of BMP2 and VEGF165 on the osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells.
- 2014
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Ingår i: Experimental and Therapeutic Medicine. - : Spandidos Publications. - 1792-1015 .- 1792-0981. ; 7:3, s. 625-629
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Tidskriftsartikel (refereegranskat)abstract
- Bone marrow-derived mesenchymal stem cells (MSCs) are dominant seed cell sources for bone regeneration. Bone morphogenetic proteins (BMPs) initiate cartilage and bone formation in a sequential cascade. Vascular endothelial growth factor (VEGF) is an essential coordinator of extracellular matrix remodeling, angiogenesis and bone formation. In the present study, the effects of the vascular endothelial growth factor 165 (VEGF165) and bone morphogenetic protein 2 (BMP2) genes on bone regeneration were investigated by the lentivirus-mediated cotransfection of the two genes into rat bone marrow-derived MSCs. The successful co-expression of the two genes in the MSCs was confirmed using quantitative polymerase chain reaction (qPCR) and western blot analysis. The results of alizarin red and alkaline phosphatase (ALP) staining at 14 days subsequent to transfection showed that the area of staining in cells transfected with BMP2 alone was higher than that in cells transfected with BMP2 and VEGF165 or untransfected control cells, while the BMP2 + VEGF165 group showed significantly more staining than the untransfected control. This indicated that BMP2 alone exhibited a stronger effect in bone regeneration than BMP2 in combination with VEGF165. Similarly, in inducing culture medium, the ALP activity of the BMP2 + VEGF165 group was notably suppressed compared with that of the BMP2 group. The overexpression of VEGF165 inhibited BMP2-induced MSC differentiation and osteogenesis in vitro. Whether or not local VEGF gene therapy is likely to affect bone regeneration in vivo requires further investigation.
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| 12. |
- Murray, Christopher J. L., et al.
(författare)
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Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - 1474-547X .- 0140-6736. ; 392:10159, s. 1995-2051
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Tidskriftsartikel (refereegranskat)abstract
- Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10–54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10–14 years and 50–54 years was estimated from data on fertility in women aged 15–19 years and 45–49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49·4% (95% uncertainty interval [UI] 46·4–52·0). The TFR decreased from 4·7 livebirths (4·5–4·9) to 2·4 livebirths (2·2–2·5), and the ASFR of mothers aged 10–19 years decreased from 37 livebirths (34–40) to 22 livebirths (19–24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83·8 million people per year since 1985. The global population increased by 197·2% (193·3–200·8) since 1950, from 2·6 billion (2·5–2·6) to 7·6 billion (7·4–7·9) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2·0%; this rate then remained nearly constant until 1970 and then decreased to 1·1% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2·5% in 1963 to 0·7% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2·7%. The global average age increased from 26·6 years in 1950 to 32·1 years in 2017, and the proportion of the population that is of working age (age 15–64 years) increased from 59·9% to 65·3%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1·0 livebirths (95% UI 0·9–1·2) in Cyprus to a high of 7·1 livebirths (6·8–7·4) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0·08 livebirths (0·07–0·09) in South Korea to 2·4 livebirths (2·2–2·6) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0·3 livebirths (0·3–0·4) in Puerto Rico to a high of 3·1 livebirths (3·0–3·2) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2·0% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress. Funding: Bill & Melinda Gates Foundation.
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| 13. |
- Ni, Jingwen, et al.
(författare)
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天山典型流域水文多要素模拟与气候变化影响预估
- 2023
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Ingår i: Journal of Glaciology and Geocryology. - 1000-0240. ; 45:6, s. 1875-1886
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Tidskriftsartikel (refereegranskat)abstract
- Because of varied topography and landscape heterogeneity，Tianshan Mountain has extremely complex hydrological processes. Considering that the climate change poses a great threat to the water security，it’s necessary to simulate the change of water elements quantitatively and systematically along with elevation. In this study，we applied the modified FLEXG-Δh model to four classic river basins in Tianshan Mountain in consideration of glacier area changes. The results suggested that：（1）FLEXG-Δh model has high simulation accuracy for the historical runoff process because the average Kling-Gupta coefficient（IKGE）in calibration is 0. 75 and IKGE in validation is 0. 60. （2）Precipitation increases along with elevation while runoff and evaporation increase first but then decreased，with the maximum values at 4 000 m and 2 000 m respectively. The height zone with the greatest runoff is mainly affected by the glacier cover，while it is the distribution of forest for the greatest evaporation. （3）By 2100，the glaciers at low altitudes will melt significantly，while there will be a little melting above 4 500 m. Under SSP1-RCP2. 6 and SSP5-RCP8. 5 scenarios，145 and 222 glaciers will completely melt and the volume of glaciers will decrease 1. 81×104 km3（54% of the existing glaciers）and 2. 44×104 km3（73% of the existing glaciers），respectively. In the SSP5-RCP8. 5 scenario，the rise of temperature will increase the evap⁃ oration but lead to the fact that the runoff depth will decrease 0. 16~1. 40 mm·a-1 below 4 000 m and increase 0. 20~0. 67 mm·a-1 above 4 000 m ，causing the height of peak value will go up by about 500 m. Under SSP1-RCP2. 6 scenario，there will be few obvious changes. This study presented the vertical zonal law of hydrology and vegetation，and predicted the impact of global changes on the Tianshan Mountains，which provided theoreti⁃ cal support for water utilization and sustainable development.
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| 14. |
- Semakula, Henry Musoke, et al.
(författare)
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Prediction of future malaria hotspots under climate change in sub-Saharan Africa
- 2017
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Ingår i: Climatic Change. - : Springer Science and Business Media LLC. - 0165-0009 .- 1573-1480. ; 143:3-4, s. 415-428
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Tidskriftsartikel (refereegranskat)abstract
- Malaria is a climate sensitive disease that is causing rampant deaths in sub-Saharan Africa (SSA) and its impact is expected to worsen under climate change. Thus, pre-emptive policies for future malaria control require projections based on integrated models that can accommodate complex interactions of both climatic and non-climatic factors that define malaria landscape. In this paper, we combined Geographical Information System (GIS) and Bayesian belief networks (BBN) to generate GIS-BBN models that predicted malaria hotspots in 2030, 2050 and 2100 under representative concentration pathways (RCPs) 4.5 and 8.5. We used malaria data of children of SSA, gridded environmental and social-economic data together with projected climate data from the 21 Coupled Model Inter-comparison Project Phase 5 models to compile the GIS-BBN models. Our model on which projections were made has an accuracy of 80.65% to predict the high, medium, low and no malaria prevalence categories correctly. The non-spatial BBN model projection shows a moderate variation in malaria reduction for the high prevalence category among RCPs. Under the low prevalence category, an increase in malaria is seen but with little variation ranging between 4.6 and 5.6 percentage points. Spatially, under RCP 4.5, most parts of SSA will have medium malaria prevalence in 2030, while under RCP 8.5, most parts will have no malaria except in the highlands. Our BBN-GIS models show an overall shift of malaria hotspots from West Africa to the eastern and southern parts of Africa especially under RCP 8.5. RCP 8.5 will not expand the high and medium malaria prevalence categories in all the projection years. The generated probabilistic maps highlight future malaria hotspots under climate change on which pre-emptive policies can be based.
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| 15. |
- Xiao, Zhiqiang, et al.
(författare)
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Systematic Engineering of Saccharomyces cerevisiae Chassis for Efficient Flavonoid-7-O-Disaccharide Biosynthesis
- 2023
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Ingår i: ACS Synthetic Biology. - 2161-5063. ; 12:9, s. 2740-2749
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Tidskriftsartikel (refereegranskat)abstract
- Flavonoids are an essential class of secondary metabolites found in plants and possess various nutritional, medicinal, and agricultural properties. However, the poor water solubility of flavonoid aglycones limits their potential applications. To overcome this issue, glycosylation is a promising approach for improving water solubility and bioavailability. In this study, we constructed a flavonoid-7-O-disaccharide biosynthetic pathway with flavonoid aglycones as substrates in Saccharomyces cerevisiae. Subsequently, through metabolic engineering and promoter strategies, we constructed a UDP-rhamnose regeneration system and optimized the UDP-glucose (UDPG) synthetic pathway. The optimized strain produced up to 131.3 mg/L eriocitrin. After this, the chassis cells were applied to other flavonoids, with substrates such as (2S)-naringenin, (2S)-hesperetin, diosmetin, and (2S)-eriodictyol, which resulted in the synthesis of 179.9 mg/L naringin, 276.6 mg/L hesperidin, 249.0 mg/L neohesperidin, 30.4 mg/L diosmin, and 100.7 mg/L neoeriocitrin. To the best of our knowledge, this is the first report on the biosynthesis of flavonoid-7-O-disaccharide.
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| 16. |
- Zhang, Chenbin, et al.
(författare)
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Data-driven lithium-ion battery states estimation using neural networks and particle filtering
- 2019
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Ingår i: International Journal of Energy Research. - : Hindawi Limited. - 1099-114X .- 0363-907X. ; 43:14, s. 8230-8241
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Tidskriftsartikel (refereegranskat)abstract
- The state of charge and state of health estimations are two of the most crucial functions of a battery management system, which are the quantified evaluation of driving mileage and remaining useful life of electric vehicles. This paper investigates a novel data-driven–enabled battery states estimation method by combining recurrent neural network modeling and particle-filtering–based errors redress. First, a recurrent neural network with long-short time memory is employed to learn the long-term nonlinear relation between batteries states and measurable signals of lithium-ion batteries, such as current, voltage, and temperature. Second, to denoise the estimation errors of the neural network model, particle filtering is employed to smooth the state of charge estimation results. Third, the terminal voltage difference of battery is highly related to the internal resistance of the battery, which is thus taken as a new input to track the internal resistance of the battery. The performance of the proposed method is verified by multiple comparisons with conventional techniques under randomized loading profiles and different temperatures.
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