Publications by authors named "Juanjuan Zhang"

203 Publications

Rapid and cost-effective screening of CRISPR/Cas9-induced mutants by DNA-guided Argonaute nuclease.

Biotechnol Lett 2021 Sep 17. Epub 2021 Sep 17.

National Clinical Research Center for Infectious Diseases, Southern University of Science and Technology, Shenzhen Third People's Hospital, Shenzhen, China.

Objective: With the widespread application of CRISPR/Cas9 gene editing technology, new methods are needed to screen mutants quickly and effectively. Here, we aimed to develop a simple and cost-effective method to screen CRISPR/Cas9-induced mutants.

Result: We report a novel method to identify CRISPR/Cas9-induced mutants through a DNA-guided Argonaute nuclease derived from the archaeon Pyrococcus furiosus. We demonstrated that the Pyrococcus furiosus Argonaute (PfAgo)-based method could distinguish among biallelic mutants, monoallelic mutants and wild type (WT). Furthermore, this method was able to identify 1 bp indel mutations.

Conclusion: The PfAgo-based method is simple to implement and can be applied to screen biallelic mutants and mosaic mutants generated by CRISPR-Cas9 or other kinds of gene editing tools.
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http://dx.doi.org/10.1007/s10529-021-03177-zDOI Listing
September 2021

Effect of NTN and Lmx1 on the Notch Signaling Pathway during the Differentiation of Human Bone Marrow Mesenchymal Stem Cells into Dopaminergic Neuron-Like Cells.

Parkinsons Dis 2021 31;2021:6676709. Epub 2021 Jul 31.

Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, China.

Human bone marrow mesenchymal stem cells (h-BMSCs) have the potential to differentiate into dopaminergic neuron-like cells to treat Parkinson's disease. The Notch signaling pathway has been implicated in the regulation of cell fate decisions such as differentiation of BMSCs. This study investigated changes in the expression of Notch-related genes in the differentiation of BMSCs in vitro into dopaminergic (DA) neuron-like cells. BMSCs transfected with empty lentiviral vectors served as the control group and those transfected with NTN and Lmx1 recombinant lentiviral vectors served as the experimental group. After induction and culture of NTN and Lmx1-transfected h-BMSCs for 21 days, the cells exhibited features of dopaminergic neuron-like cells, which were observed by transmission and scanning electron microscopy and verified by immunofluorescence of tyrosine hydroxylase (TH) and dopamine transporter (DAT). These induced cells could secrete dopamine and had basic action potentials. Expression of the neural stem cell (NSC) markers, including octamer-binding protein (), paired box gene 6 (), and sex determining region Y-box 1 (), increased on day 14 of induction and decreased on day 21 of induction during differentiation. The human Notch signaling pathway PCR array showed a differential expression of Notch-related genes during the differentiation of h-BMSCs into DA neuron-like cells in vitro relative to that in the control group. In conclusion, h-BMSCs overexpressing NTN and Lmx1 can successfully be induced to differentiate into dopaminergic neuron-like cells with a neuronal phenotype exhibiting fundamental biological functions in vitro, and NTN and Lmx1 may affect the expression of Notch-related genes during differentiation.
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http://dx.doi.org/10.1155/2021/6676709DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8349261PMC
July 2021

Time-varying optimization of COVID-19 vaccine prioritization in the context of limited vaccination capacity.

Nat Commun 2021 08 3;12(1):4673. Epub 2021 Aug 3.

School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China.

Dynamically adapting the allocation of COVID-19 vaccines to the evolving epidemiological situation could be key to reduce COVID-19 burden. Here we developed a data-driven mechanistic model of SARS-CoV-2 transmission to explore optimal vaccine prioritization strategies in China. We found that a time-varying vaccination program (i.e., allocating vaccines to different target groups as the epidemic evolves) can be highly beneficial as it is capable of simultaneously achieving different objectives (e.g., minimizing the number of deaths and of infections). Our findings suggest that boosting the vaccination capacity up to 2.5 million first doses per day (0.17% rollout speed) or higher could greatly reduce COVID-19 burden, should a new wave start to unfold in China with reproduction number ≤1.5. The highest priority categories are consistent under a broad range of assumptions. Finally, a high vaccination capacity in the early phase of the vaccination campaign is key to achieve large gains of strategic prioritizations.
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http://dx.doi.org/10.1038/s41467-021-24872-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8333090PMC
August 2021

Herd immunity induced by COVID-19 vaccination programs to suppress epidemics caused by SARS-CoV-2 wild type and variants in China.

medRxiv 2021 Jul 23. Epub 2021 Jul 23.

To allow a return to a pre-COVID-19 lifestyle, virtually every country has initiated a vaccination program to mitigate severe disease burden and control transmission; over 3.6 billion vaccine doses have been administered as of July 2021. However, it remains to be seen whether herd immunity will be within reach of these programs, especially as more transmissible SARS-CoV-2 variants continue to emerge. To address this question, we developed a data-driven model of SARS-CoV-2 transmission for Shanghai, China, a population with low prior immunity from natural infection. We found that extending the vaccination program to individuals aged 3-17 years plays a key role to reach herd immunity for the original SARS-CoV-2 lineages. With a vaccine efficacy 74% against infection, vaccine-induced herd immunity would require coverages of 93% or higher. Herd immunity for new variants, such as Alpha or Delta, can only be achieved with more efficacious vaccines and coverages above 80-90%. A continuation of the current pace of vaccination in China would reach 72% coverage by September 2021; although this program would fail to reach herd immunity it would reduce deaths by 95-100% in case of an outbreak. Efforts should be taken to increase population's confidence and willingness to be vaccinated and to guarantee highly efficacious vaccines against more transmissible variants of concern.
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http://dx.doi.org/10.1101/2021.07.23.21261013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8328074PMC
July 2021

Association between dietary onion intake and subclinical hypothyroidism in adults: a population-based study from an iodine-replete area.

Endocrine 2021 Jul 31. Epub 2021 Jul 31.

Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, Tianjin, China.

Purpose: The protective effect of onion against thyroid hypofunction has been reported in animal studies. However, in humans, the association between onion consumption and subclinical hypothyroidism (SCH) are unclear. The study sought to explore the association between habitual onion intake and SCH among adult population from an iodine-replete area.

Methods: A cross-sectional study (6515 men and 5290 women) was performed in Tianjin, China. Frequency of onion consumption was assessed using a valid self-administered food frequency questionnaire. Serum free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) were determined by chemiluminescence immunoassay. SCH was diagnosed with TSH > 4.78 mIU/L. Multiple logistic regression was used to evaluate the association of onion intake with SCH.

Results: The prevalence of SCH was 2.56% in men and 7.18% in women, respectively. In women, the fully adjusted odds ratios [95% confidence interval (CI)] of having SCH across increasing frequency of onion intake were 1.00 (reference) for <1 time/week, 0.99 (0.73, 1.34) for 1-3 times/week, 0.74 (0.53, 1.03) for 4-6 times/week, and 0.67 (0.47, 0.97) for ≥7 times/week (P for trend <0.01). However, we observed no significant association between onion intake and SCH in men. Stratified analyses suggested a potential effect modification by age: the odds ratios (95% CI) across extreme quartiles was 0.37 (0.17, 0.80) in <40 women and 1.11 (0.51, 2.47) in >60 women.

Conclusions: Frequent consumption of onion is inversely associated with SCH in adult women from an iodine-replete area. Further studies are needed to explore the casual relationship. TRIAL REGISTRATION WEBSITE: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000031137.
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http://dx.doi.org/10.1007/s12020-021-02790-2DOI Listing
July 2021

Assocation Between Leber's Hereditary Optic Neuropathy and MT-ND1 3460G>A Mutation-Induced Alterations in Mitochondrial Function, Apoptosis, and Mitophagy.

Invest Ophthalmol Vis Sci 2021 Jul;62(9):38

Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China.

Purpose: To investigate the molecular mechanism underlying the Leber's hereditary optic neuropathy (LHON)-linked MT-ND1 3460G>A mutation.

Methods: Cybrid cell models were generated by fusing mitochondrial DNA-less ρ0 cells with enucleated cells from a patient carrying the m.3460G>A mutation and a control subject. The impact of m.3460G>A mutations on oxidative phosphorylation was evaluated using Blue Native gel electrophoresis, and measurements of oxygen consumption were made with an extracellular flux analyzer. Assessment of reactive oxygen species (ROS) production in cell lines was performed by flow cytometry with MitoSOX Red reagent. Assays for apoptosis and mitophagy were undertaken via immunofluorescence analysis.

Results: Nineteen Chinese Han pedigrees bearing the m.3460G>A mutation exhibited variable penetrance and expression of LHON. The m.3460G>A mutation altered the structure and function of MT-ND1, as evidenced by reduced MT-ND1 levels in mutant cybrids bearing the mutation. The instability of mutated MT-ND1 manifested as defects in the assembly and activity of complex I, respiratory deficiency, diminished mitochondrial adenosine triphosphate production, and decreased membrane potential, in addition to increased production of mitochondrial ROS in the mutant cybrids carrying the m.3460G>A mutation. The m.3460G>A mutation mediated apoptosis, as evidenced by the elevated release of cytochrome c into the cytosol and increasing levels of the apoptotic-associated proteins BAK, BAX, and PARP, as well as cleaved caspases 3, 7, and 9, in the mutant cybrids. The cybrids bearing the m.3460G>A mutation exhibited reduced levels of autophagy protein light chain 3, accumulation of autophagic substrate P62, and impaired PTEN-induced kinase 1/parkin-dependent mitophagy.

Conclusions: Our findings highlight the critical role of m.3460G>A mutation in the pathogenesis of LHON, manifested by mitochondrial dysfunction and alterations in apoptosis and mitophagy.
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http://dx.doi.org/10.1167/iovs.62.9.38DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8322717PMC
July 2021

Progressive cortical and sub-cortical alterations in patients with anti-N-methyl-D-aspartate receptor encephalitis.

J Neurol 2021 Jul 23. Epub 2021 Jul 23.

Department of Neurology, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei, Anhui Province, China.

Background: Advanced structural analyses are increasingly being highly valued to uncover pathophysiological understanding of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. Therefore, we aimed to explore whether and how antibody-mediated NMDAR dysfunction affected cortical and sub-cortical brain morphology and their relationship with clinical symptoms.

Methods: We performed surface-based morphometry analyses, hippocampal segmentation, and correlational analyses in 24 patients with anti-NMDAR encephalitis after acute disease stage and 30 normal controls (NC) in this case-control study.

Results: Patients showed significantly decreased cortical alterations mainly in language network (LN) and default mode network (DMN), as well as decreased gray matter volume in left cornu ammonis 1 (CA1) body of hippocampus. Further correlation analyses showed that the decreased cortical thickness in the right superior frontier gyrus was associated with decreased cognitive scores, the decreased cortical volume in the right pars triangulari and decreased surface area in the right pars operculari were associated with decreased memory scores, whereas decreased gray matter volume in the left CA1 body was significantly correlated with longer time between first symptom and imaging in the patients.

Conclusion: These results suggested that cognitive impairments resulted from long-term sequelae of the encephalitis were mainly associated with cortical alterations in LN and DMN and sub-cortical atrophy of left CA1 body, which can be served as effective features to assess disease progression in clinical routine examination.
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http://dx.doi.org/10.1007/s00415-021-10643-1DOI Listing
July 2021

Quantitative label-free optical technique to analyze the ultrastructure changes and spatiotemporal relationship of enamel induced by Msx2 deletion.

J Biophotonics 2021 Jul 9:e202100165. Epub 2021 Jul 9.

SATCM Third Grade Laboratory of Chinese Medicine and Photonics Technology and Guangdong Provincial Key Laboratory of Laser Life Science, GuangzhouKey Laboratory of Spectral Analysis and Functional Probes, College of Biophotonics, South China Normal University, Guangzhou, China.

New advances in the molecular mechanism of enamel mineralization reveal the practical significance of regenerative medicine in clinical transformation. Muscle segment homeobox 2 (MSX2), a transcription factor, is recently reported to be closely associated with the amelogenesis imperfecta (AI). To elucidate the biomineralization framework of AI enamel, herein, Msx2 gene mutant mice are investigated by dual-mode noninvasive spectroscopic analytical techniques for the first time. Optical coherence tomography (OCT) records the depth-resolved structural information of mice teeth, where a dramatic decrease in enamel thickness and quality occurred in Msx2 deficient (Msx2 ) enamel. And it has the advantages of fast, noninvasive and low cost. Raman spectroscopy, a powerful molecular fingerprint tool, further witnesses an imbalance of inorganic and organic contents in Msx2 enamel. In addition, abnormal expression of MSX2 also influences the spatial distribution of phosphate in enamel according to the Raman spectral imaging. Therefore, OCT integrated with Raman spectroscopy provides the quantitative label-free optical parameters of both the physical structure and chemical component in mice enamel, which strengthens the understanding of the biomineralization process underlying the Msx2-related amelogenesis imperfect.
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http://dx.doi.org/10.1002/jbio.202100165DOI Listing
July 2021

Social Contact Patterns and Implications for Infectious Disease Transmission: A Systematic Review and Meta-Analysis of Contact Surveys.

medRxiv 2021 Jun 15. Epub 2021 Jun 15.

Background: Transmission of respiratory pathogens such as SARS-CoV-2 depends on patterns of contact and mixing across populations. Understanding this is crucial to predict pathogen spread and the effectiveness of control efforts. Most analyses of contact patterns to date have focussed on high-income settings.

Methods: Here, we conduct a systematic review and individual-participant meta-analysis of surveys carried out in low- and middle-income countries and compare patterns of contact in these settings to surveys previously carried out in high-income countries. Using individual-level data from 28,503 participants and 413,069 contacts across 27 surveys we explored how contact characteristics (number, location, duration and whether physical) vary across income settings.

Results: Contact rates declined with age in high- and upper-middle-income settings, but not in low-income settings, where adults aged 65+ made similar numbers of contacts as younger individuals and mixed with all age-groups. Across all settings, increasing household size was a key determinant of contact frequency and characteristics, but low-income settings were characterised by the largest, most intergenerational households. A higher proportion of contacts were made at home in low-income settings, and work/school contacts were more frequent in high-income strata. We also observed contrasting effects of gender across income-strata on the frequency, duration and type of contacts individuals made.

Conclusions: These differences in contact patterns between settings have material consequences for both spread of respiratory pathogens, as well as the effectiveness of different non-pharmaceutical interventions.

Funding: This work is primarily being funded by joint Centre funding from the UK Medical Research Council and DFID (MR/R015600/1).
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http://dx.doi.org/10.1101/2021.06.10.21258720DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8219108PMC
June 2021

Despite vaccination, China needs non-pharmaceutical interventions to prevent widespread outbreaks of COVID-19 in 2021.

Nat Hum Behav 2021 08 22;5(8):1009-1020. Epub 2021 Jun 22.

Shanghai Institute of Infectious Disease and Biosecurity, School of Public Health, Fudan University, Shanghai, China.

COVID-19 vaccination is being conducted in over 200 countries and regions to control SARS-CoV-2 transmission and return to a pre-pandemic lifestyle. However, understanding when non-pharmaceutical interventions (NPIs) can be lifted as immunity builds up remains a key question for policy makers. To address this, we built a data-driven model of SARS-CoV-2 transmission for China. We estimated that, to prevent the escalation of local outbreaks to widespread epidemics, stringent NPIs need to remain in place at least one year after the start of vaccination. Should NPIs alone be capable of keeping the reproduction number (R) around 1.3, the synergetic effect of NPIs and vaccination could reduce the COVID-19 burden by up to 99% and bring R below the epidemic threshold in about 9 months. Maintaining strict NPIs throughout 2021 is of paramount importance to reduce COVID-19 burden while vaccines are distributed to the population, especially in large populations with little natural immunity.
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http://dx.doi.org/10.1038/s41562-021-01155-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8373613PMC
August 2021

Leber's Hereditary Optic Neuropathy Arising From the Synergy Between ND1 3635G>A Mutation and Mitochondrial YARS2 Mutations.

Invest Ophthalmol Vis Sci 2021 Jun;62(7):22

Key Laboratory of Reproductive Genetics, Ministry of Education of PRC, The Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.

Purpose: To investigate the mechanism underlying the synergic interaction between Leber's hereditary optic neuropathy (LHON)-associated ND1 and mitochondrial tyrosyl-tRNA synthetase (YARS2) mutations.

Methods: Molecular dynamics simulation and differential scanning fluorimetry were used to evaluate the structure and stability of proteins. The impact of ND1 3635G>A and YARS2 p.G191V mutations on the oxidative phosphorylation machinery was evaluated using blue native gel electrophoresis and enzymatic activities assays. Assessment of reactive oxygen species (ROS) production in cell lines was performed by flow cytometry with MitoSOX Red reagent. Analysis of effect of mutations on autophagy was undertaken via flow cytometry for autophagic flux.

Results: Members of one Chinese family bearing both the YARS2 p.191Gly>Val and m.3635G>A mutations exhibited much higher penetrance of optic neuropathy than those pedigrees carrying only the m.3635G>A mutation. The m.3635G>A (p.Ser110Asn) mutation altered the ND1 structure and function, whereas the p.191Gly>Val mutation affected the stability of YARS2. Lymphoblastoid cell lines harboring both m.3635G>A and p.191Gly>Val mutations revealed more reductions in the levels of mitochondrion-encoding ND1 and CO2 than cells bearing only the m.3635G>A mutation. Strikingly, both m.3635G>A and p.191Gly>Val mutations exhibited decreases in the nucleus-encoding subunits of complex I and IV. These deficiencies manifested greater defects in the stability and activities of complex I and complex IV and overproduction of ROS and promoted greater autophagy in cell lines harboring both m.3635G>A and p.191Gly>Val mutations compared with cells bearing only the m.3635G>A mutation.

Conclusions: Our findings provide new insights into the pathophysiology of LHON arising from the synergy between ND1 3635G>A mutation and mitochondrial YARS2 mutations.
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http://dx.doi.org/10.1167/iovs.62.7.22DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8237128PMC
June 2021

Analysis of the current status and associated factors of tuberculosis knowledge, attitudes, and practices among elderly people in Shenzhen: a cross-sectional study.

BMC Public Health 2021 06 17;21(1):1163. Epub 2021 Jun 17.

Shenzhen Bao'an Center for Chronic Disease Control, NO. 332 Yu'an 2nd Road, Shenzhen, 518101, China.

Background: The incidence and risk of tuberculosis (TB) among the elderly population have increased with the ageing population in China. This study aimed to assess the current status and associated factors of TB knowledge, attitudes, and practices among elderly people in Shenzhen City, China, which may provide references for the development of TB prevention and treatment policies targeting elderly people.

Methods: A multistage random sampling method was used to collect data with a self-designed questionnaire from 1078 elderly people (response rate, 90.66%) living in Bao'an District of Shenzhen between September and October 2019. Univariate and multiple linear regression analyses were used to analyse factors associated with TB knowledge, attitudes, and practices among elderly people.

Results: Among the respondents, 3.13% had previously been treated for TB, and 3.09% of respondents had family members or friends with a previous TB history. The percentages of elderly people who were aware of TB and had positive attitudes and practices regarding TB were 69.23%, 48.87%, and 42.62%, respectively. Multiple linear stepwise regression analysis showed that elderly people with a junior high school education or higher, a family annual income per capita of less than 100,000 RMB, a better self-perceived health status, and family members or friends with a previous TB history had higher TB knowledge scores (P < 0.05). Elderly people with medical insurance, a junior high school or higher education, a family annual income per capita of less than 100,000 RMB, and family members and friends with a previous TB history had higher TB attitude scores (P < 0.05). In addition, elderly people who were older, had medical insurance, had a junior high school education or higher, and had a family annual income per capita less than 100,000 RMB had higher TB practice scores (P < 0.05).

Conclusions: Elderly people were aware of TB, but their positive attitudes and practices were at a low level. Corresponding prevention and treatment policies should be developed according to these influencing factors to reduce the incidence of TB among elderly people and improve their quality of life.
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http://dx.doi.org/10.1186/s12889-021-11240-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8210368PMC
June 2021

The Iterative Learning Gain That Optimizes Real-Time Torque Tracking for Ankle Exoskeletons in Human Walking Under Gait Variations.

Front Neurorobot 2021 28;15:653409. Epub 2021 May 28.

Department of Mechanical Engineering, Carneigie Mellon University, Pittsburgh, PA, United States.

Lower-limb exoskeletons often use torque control to manipulate energy flow and ensure human safety. The accuracy of the applied torque greatly affects how well the motion is assisted and therefore improving it is always of interest. Feed-forward iterative learning, which is similar to predictive stride-wise integral control, has proven an effective compensation to feedback control for torque tracking in exoskeletons with complicated dynamics during human walking. Although the intention of iterative learning was initially to benefit average tracking performance over multiple strides, we found that, after proper gain tuning, it can also help improve real-time torque tracking. We used theoretical analysis to predict an optimal iterative-learning gain as the inverse of the passive actuator stiffness. Walking experiments resulted in an optimum gain equal to 0.99 ± 0.38 times the predicted value, confirming our hypothesis. The results of this study provide guidance for the design of torque controllers in robotic legged locomotion systems and will help improve the performance of robots that assist gait.
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http://dx.doi.org/10.3389/fnbot.2021.653409DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8192972PMC
May 2021

Reducing the metabolic energy of walking and running using an unpowered hip exoskeleton.

J Neuroeng Rehabil 2021 06 6;18(1):95. Epub 2021 Jun 6.

Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China.

Background: Walking and running are the most common means of locomotion in human daily life. People have made advances in developing separate exoskeletons to reduce the metabolic rate of walking or running. However, the combined requirements of overcoming the fundamental biomechanical differences between the two gaits and minimizing the metabolic penalty of the exoskeleton mass make it challenging to develop an exoskeleton that can reduce the metabolic energy during both gaits. Here we show that the metabolic energy of both walking and running can be reduced by regulating the metabolic energy of hip flexion during the common energy consumption period of the two gaits using an unpowered hip exoskeleton.

Methods: We analyzed the metabolic rates, muscle activities and spatiotemporal parameters of 9 healthy subjects (mean ± s.t.d; 24.9 ± 3.7 years, 66.9 ± 8.7 kg, 1.76 ± 0.05 m) walking on a treadmill at a speed of 1.5 m s and running at a speed of 2.5 m s with different spring stiffnesses. After obtaining the optimal spring stiffness, we recruited the participants to walk and run with the assistance from a spring with optimal stiffness at different speeds to demonstrate the generality of the proposed approach.

Results: We found that the common optimal exoskeleton spring stiffness for walking and running was 83 Nm Rad, corresponding to 7.2% ± 1.2% (mean ± s.e.m, paired t-test p < 0.01) and 6.8% ± 1.0% (p < 0.01) metabolic reductions compared to walking and running without exoskeleton. The metabolic energy within the tested speed range can be reduced with the assistance except for low-speed walking (1.0 m s). Participants showed different changes in muscle activities with the assistance of the proposed exoskeleton.

Conclusions: This paper first demonstrates that the metabolic cost of walking and running can be reduced using an unpowered hip exoskeleton to regulate the metabolic energy of hip flexion. The design method based on analyzing the common energy consumption characteristics between gaits may inspire future exoskeletons that assist multiple gaits. The results of different changes in muscle activities provide new insight into human response to the same assistive principle for different gaits (walking and running).
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http://dx.doi.org/10.1186/s12984-021-00893-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8182901PMC
June 2021

Consumption of Preserved Egg Is Associated with Modestly Increased Risk of Nonalcoholic Fatty Liver Disease in Chinese Adults.

J Nutr 2021 Sep;151(9):2741-2748

Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, Tianjin, China.

Background: Although preserved egg is a traditional Chinese delicacy widely consumed in China and Southeast Asian countries, whether habitual preserved egg consumption is associated with nonalcoholic fatty liver disease (NAFLD) remains unknown.

Objectives: This study aimed to examine the association between preserved egg consumption and risk of NAFLD in a cohort of Chinese adults.

Methods: This prospective cohort study included 15,883 participants aged 19-88 y (58% women) from the TCLSIH (Tianjin Chronic Low-grade Systemic Inflammation and Health) cohort study who were free of liver diseases, cancer, and cardiovascular disease at baseline. Preserved egg consumption was assessed using an FFQ at baseline. NAFLD was diagnosed by transabdominal sonography during an annual health examination. Multivariable Cox proportional hazards regression models were used to calculate HRs and 95% CIs across categories of preserved egg consumption.

Results: During 56,002 person-years of follow-up, 3683 first incident cases of NAFLD were recorded. After adjustment for sociodemographic characteristics, lifestyle risk factors, total energy intake, egg intake, and eating patterns, the multivariable HRs (95% CIs) of incident NAFLD according to categories of preserved egg consumption were 1.00 (reference) for never, 1.05 (0.98, 1.14) for <1 time/wk, 1.09 (0.96, 1.24) for 1 time/wk, and 1.26 (1.09, 1.46) for ≥2 times/wk (P-trend < 0.01). The results were robust to a series of sensitivity analyses.

Conclusions: Habitual preserved egg consumption is associated with a modestly higher risk of NAFLD among the Chinese adult population. The mechanism underlying this association warrants further research.This trial was registered at www.umin.ac.jp/ctr/ as UMIN000027174.
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http://dx.doi.org/10.1093/jn/nxab163DOI Listing
September 2021

The absence of muscle segment homeobox 2 leads to the pyroptosis of ameloblasts by inducing squamous epithelial hyperplasia in the enamel organ.

J Cell Mol Med 2021 May 26. Epub 2021 May 26.

Department of Oral Biology, School of Bioscience and Technology, Weifang Medical University, Weifang, China.

Muscle segment homeobox 2 (MSX2) has been confirmed to be involved in the regulation of early tooth development. However, the role of MSX2 has not been fully elucidated in enamel development. To research the functions of MSX2 in enamel formation, we used a Msx2 (KO) mouse model with no full Msx2 gene. In the present study, the dental appearance and enamel microstructure were detected by scanning electron microscopy and micro-computed tomography. The results showed that the absence of Msx2 resulted in enamel defects, leading to severe tooth wear in KO mice. To further investigate the mechanism behind the phenotype, we performed detailed histological analyses of the enamel organ in KO mice. We discovered that ameloblasts without Msx2 could secrete a small amount of enamel matrix protein in the early stage. However, the enamel epithelium occurred squamous epithelial hyperplasia and partial keratinization in the enamel organ during subsequent developmental stages. Ameloblasts depolarized and underwent pyroptosis. Overall, during the development of enamel, MSX2 affects the formation of enamel by regulating the function of epithelial cells in the enamel organ.
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http://dx.doi.org/10.1111/jcmm.16646DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8256348PMC
May 2021

Mechanistic insights into mitochondrial tRNA 3'-end metabolism deficiency.

J Biol Chem 2021 07 21;297(1):100816. Epub 2021 May 21.

Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, Zhejiang, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Center for Mitochondrial Genetics, Zhejiang Provincial Key Laboratory of Genetic & Developmental Disorders, Zhejiang Univesity, Hangzhou, Zhejiang, China; Division of Mitochondrial Biomedicine, Joint Institute of Genetics and Genome Medicine between Zhejiang University and University of Toronto, Hangzhou, Zhejiang, China. Electronic address:

Mitochondrial tRNA 3'-end metabolism is critical for the formation of functional tRNAs. Deficient mitochondrial tRNA 3'-end metabolism is linked to an array of human diseases, including optic neuropathy, but their pathophysiology remains poorly understood. In this report, we investigated the molecular mechanism underlying the Leber's hereditary optic neuropathy (LHON)-associated tRNA 5587A>G mutation, which changes a highly conserved adenosine at position 73 (A73) to guanine (G73) on the 3'-end of the tRNA acceptor stem. The m.5587A>G mutation was identified in three Han Chinese families with suggested maternal inheritance of LHON. We hypothesized that the m.5587A>G mutation altered tRNA 3'-end metabolism and mitochondrial function. In vitro processing experiments showed that the m.5587A>G mutation impaired the 3'-end processing of tRNA precursors by RNase Z and inhibited the addition of CCA by tRNA nucleotidyltransferase (TRNT1). Northern blot analysis revealed that the m.5587A>G mutation perturbed tRNA aminoacylation, as evidenced by decreased efficiency of aminoacylation and faster electrophoretic mobility of mutated tRNA in these cells. The impact of m.5587A>G mutation on tRNA function was further supported by increased melting temperature, conformational changes, and reduced levels of this tRNA. Failures in tRNA metabolism impaired mitochondrial translation, perturbed assembly and activity of oxidative phosphorylation complexes, diminished ATP production and membrane potential, and increased production of reactive oxygen species. These pleiotropic defects elevated apoptotic cell death and promoted mitophagy in cells carrying the m.5587A>G mutation, thereby contributing to visual impairment. Our findings may provide new insights into the pathophysiology of LHON arising from mitochondrial tRNA 3'-end metabolism deficiency.
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http://dx.doi.org/10.1016/j.jbc.2021.100816DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8212662PMC
July 2021

Selection of Muscle-Activity-Based Cost Function in Human-in-the-Loop Optimization of Multi-Gait Ankle Exoskeleton Assistance.

IEEE Trans Neural Syst Rehabil Eng 2021 28;29:944-952. Epub 2021 May 28.

Using "human-in-the-loop" (HIL) optimization can obtain suitable exoskeleton assistance patterns to improve walking economy. However, there are differences in these patterns under different gait conditions, and currently most HIL optimizations use metabolic cost, which requires long periods to be estimated for each control law, as the physiological objective to minimize. We aimed to construct a muscle-activity-based cost function and to find the appropriate initial assistance patterns in HIL optimization of multi-gait ankle exoskeleton assistance. One healthy subject walked assisted by an ankle exoskeleton under nine gait conditions and each condition was the combination of different walking speeds, ground slopes and load weights. Ten assistance patterns were provided for the subject under each gait condition. Then we constructed a cost function based on surface electromyography signals of four lower leg muscles and select the muscle weight combination by using particle swarm optimization algorithm to compose the cost function with maximum differences between different assistance patterns. The mean weights of medial gastrocnemius, lateral gastrocnemius, soleus and tibialis anterior activity under all gait conditions are 0.153, 0.104, 0.953 and 0.145, respectively. Then we verified the effectiveness of this cost function by optimization and validation experiments conducted on four subjects. Our results are expected to guide the selection of muscle-activity-based cost functions and improve the time efficiency of HIL optimization.
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http://dx.doi.org/10.1109/TNSRE.2021.3082198DOI Listing
June 2021

Screening and potential role of tRFs and tiRNAs derived from tRNAs in the carcinogenesis and development of lung adenocarcinoma.

Oncol Lett 2021 Jul 2;22(1):506. Epub 2021 May 2.

Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, Yunnan 650118, P.R. China.

Accumulating evidence has indicated that a group of novel molecules, known as transfer RNA (tRNA)-derived fragments (tRFs) and tRNA halves (tiRNAs), which are derived from tRNAs, serve an essential role in numerous types of human disease, in particular solid tumors. However, to the best of our knowledge, the underlying mechanisms of the effect of tRFs and tiRNAs in lung adenocarcinoma have not been reported. The present study aimed to determine the differential expression levels of tRFs and tiRNAs in lung adenocarcinoma and adjacent tissues using a NextSeq system, and further investigated their potential target genes via bioinformatics analysis. Kyoto Encyclopedia of Genes and Genomes signaling pathway and Gene Ontology functional term enrichment analyses were performed to investigate the function of these target genes in the occurrence and development of lung adenocarcinoma. In patients with lung adenocarcinoma, 338 types of tRFs and tiRNAs were detected via sequencing, 284 of which were not previously reported in the tRF database. Compared with the adjacent tissues, 17 types of tRFs and tiRNAs comprising 34 subtypes were found to be abnormally expressed in lung adenocarcinoma tissues, 20 of which were upregulated and 14 downregulated. Reverse transcription-quantitative PCR verification revealed that the expression levels of tiRNA-Lys-CTT-002, tRF-Val-CAC-010 and tRF-Val-CAC-011 were significantly upregulated, while those of tRF-Ser-TGA-005 were downregulated in lung adenocarcinoma tissues. Bioinformatics analysis identified that tRF-Ser-TGA-005 participated in the 'cellular response to transforming growth factor β stimulus' and tRF-Val-CAC-010 and tRF-Val-CAC-011 participated in the 'Hedgehog signaling pathway'. In conclusion, the results of the present study suggested that tRFs and tiRNAs may be closely associated with the pathogenesis and development of lung adenocarcinoma, providing a novel insight for further studies into lung adenocarcinoma.
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http://dx.doi.org/10.3892/ol.2021.12767DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8114470PMC
July 2021

Key Characteristics of Nitrous Oxide-Induced Neurological Disorders and Differences Between Populations.

Front Neurol 2021 27;12:627183. Epub 2021 Apr 27.

Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, China.

Nitrous oxide (NO), commonly known as laughing gas, is inhaled recreationally because it produces the feelings of euphoria and freedom from pain. The risk of neurological dysfunction secondary to NO abuse and its clinical diagnosis are, however, not yet sufficiently recognized, especially in China. Here, we have summarized the key clinical characteristics of NO-induced neurological disorders. We recruited 20 patients with NO-induced neurological disorders and analyzed their clinical features, laboratory data, magnetic resonance imaging and electromyography. We also carried out a literature review and compared 99 previously reported patients with our case series to confirm our results. Subgroup analysis was performed to explore the difference in demographical and clinical characteristics of NO abuse between Asian and non-Asian patients. The most common initial symptoms of NO-induced neurological disorders were weakness and/or paresthesia. Most patients presented with myelopathy and/or peripheral neuropathy. The most commonly involved segment of the spinal cord was the cervical spinal cord, extending over 4-6 vertebral levels, but more than half of the patients with myelopathy had no sensory change at the corresponding spinal level. Homocysteine was found to be the most sensitive and practical indicator for diagnosis. Subgroup analysis showed that the Asian patients (median: 22.0 years old, Q1-Q3:19.0-26.0 years old) with NO abuse were younger than non-Asian patients [26.0 (22.3-31.0) years old, = 2.8 × 10]. The incidence of myelopathy combined with peripheral neuropathy was significantly higher in Asian patients than in non-Asian patients, who had myelopathy or peripheral neuropathy ( = 2 × 10). Key clinical characteristics of NO abuse are longitudinally extensive cervical myelopathy and peripheral neuropathy. Recognition of these traits in young people in the age group of 20-30 years will provide important guidance for accurate diagnosis of neurological disease associated with NO abuse. The clinical manifestations differ in Asian patients and non-Asian patients.
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http://dx.doi.org/10.3389/fneur.2021.627183DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8110825PMC
April 2021

Hydrazine-Containing Heterocycle Cytochalasan Derivatives From Hydrazinolysis of Extracts of a Desert Soil-Derived Fungus 375.

Front Chem 2021 21;9:620589. Epub 2021 Apr 21.

Zhengzhou Key Laboratory of Synthetic Biology of Natural Products, Zhengzhou Key Laboratory of Medicinal Resources Research, Comprehensive Utilization of Edible and Medicinal Plant Resources Engineering Technology Research Center, Huanghe Science and Technology College, Zhengzhou, China.

"Diversity-enhanced extracts" is an effective method of producing chemical libraries for the purpose of drug discovery. Three rare new cytochalasan derivative chaetoglobosins B-B (-) were obtained from chemically engineered crude broth extracts of 375 prepared by reacting with hydrazine monohydrate and four known metabolite chaetoglobosins () were also identified from the fungus. The structures were identified by NMR and MS analysis and electronic circular dichroism simulation. In addition, the antiproliferative activities of these compounds were also evaluated, and the drug-resistant activities of cytochalasans were evaluated for the first time. Compound possessed potent activity against four human cancer cells (A549, HCC827, SW620, and MDA-MB-231), and two drug-resistant HCC827 cells (Gefitinib-resistant, Osimertinib-resistant) compared with the positive controls.
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http://dx.doi.org/10.3389/fchem.2021.620589DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8097171PMC
April 2021

The impact of relaxing interventions on human contact patterns and SARS-CoV-2 transmission in China.

Sci Adv 2021 05 7;7(19). Epub 2021 May 7.

School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China.

Nonpharmaceutical interventions to control SARS-CoV-2 spread have been implemented with different intensity, timing, and impact on transmission. As a result, post-lockdown COVID-19 dynamics are heterogeneous and difficult to interpret. We describe a set of contact surveys performed in four Chinese cities (Wuhan, Shanghai, Shenzhen, and Changsha) during the pre-pandemic, lockdown and post-lockdown periods to quantify changes in contact patterns. In the post-lockdown period, the mean number of contacts increased by 5 to 17% as compared to the lockdown period. However, it remains three to seven times lower than its pre-pandemic level sufficient to control SARS-CoV-2 transmission. We find that the impact of school interventions depends nonlinearly on the intensity of other activities. When most community activities are halted, school closure leads to a 77% decrease in the reproduction number; in contrast, when social mixing outside of schools is at pre-pandemic level, school closure leads to a 5% reduction in transmission.
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http://dx.doi.org/10.1126/sciadv.abe2584DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8104862PMC
May 2021

Leaf area index estimation model for UAV image hyperspectral data based on wavelength variable selection and machine learning methods.

Plant Methods 2021 May 3;17(1):49. Epub 2021 May 3.

Science College of Information and Management, Henan Agricultural University, #63 Nongye Road, Zhengzhou, 450002, Henan, China.

Background: To accurately estimate winter wheat leaf area index (LAI) using unmanned aerial vehicle (UAV) hyperspectral imagery is crucial for crop growth monitoring, fertilization management, and development of precision agriculture.

Methods: The UAV hyperspectral imaging data, Analytical Spectral Devices (ASD) data, and LAI were simultaneously obtained at main growth stages (jointing stage, booting stage, and filling stage) of various winter wheat varieties under various nitrogen fertilizer treatments. The characteristic bands related to LAI were extracted from UAV hyperspectral data with different algorithms including first derivative (FD), successive projections algorithm (SPA), competitive adaptive reweighed sampling (CARS), and competitive adaptive reweighed sampling combined with successive projections algorithm (CARS_SPA). Furthermore, three modeling machine learning methods including partial least squares regression (PLSR), support vector machine regression (SVR), and extreme gradient boosting (Xgboost) were used to build LAI estimation models.

Results: The results show that the correlation coefficient between UAV and ASD hyperspectral data is greater than 0.99, indicating the UAV data can be used for estimation of wheat growth information. The LAI bands selected by using different algorithms were slightly different among the 15 models built in this study. The Xgboost model using nine consecutive characteristic bands selected by CARS_SPA algorithm as input was proved to have the best performance. This model yielded identical results of coefficient of determination (0.89) for both calibration set and validation set, indicating a high accuracy of this model.

Conclusions: The Xgboost modeling method in combine with CARS_SPA algorithm can reduce input variables and improve the efficiency of model operation. The results provide reference and technical support for nondestructive and rapid estimation of winter wheat LAI by using UAV.
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http://dx.doi.org/10.1186/s13007-021-00750-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8094481PMC
May 2021

The consumption of wholegrain is related to depressive symptoms among Chinese adults: a cross-sectional study.

Eur J Clin Nutr 2021 Apr 30. Epub 2021 Apr 30.

Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, Tianjin, China.

Background: Wholegrains contribute a range of beneficial nutrients, such as dietary fiber and several minerals and vitamins, that are beneficial to depressive symptoms. However, there are a few studies aimed at exploring whether a wholegrain diet is related to depressive symptoms. We conducted this study to investigate the relationship between wholegrains consumption and depressive symptoms.

Methods: This cross-sectional study included a total of 24,776 (mean age: 39.9 years, age range: 18.1-91.3 years; males, 54.1%) inhabitants living in Tianjin, China. Wholegrains consumption was assessed using a valid self-administered food frequency questionnaire. Depressive symptoms were evaluated using the Chinese version of Zung Self-Rating Depression Scale (SDS) and the cutoff point was set at 45. Multiple logistic regression analysis was used to estimate the relationship between wholegrains consumption and depressive symptoms.

Results: The prevalence of depressive symptoms was 19.1% and 22.4% in males and females, respectively. After adjustments for potential confounding factors, the odds ratios (95% confidence intervals) of depressive symptoms across wholegrains consumption were 0.77 (0.65-0.91) for <1 time/week, 0.73 (0.62-0.86) for 1 time/week and 0.68 (0.59-0.79) for ≥2 time/week in males compared with the control group (almost never). In females, the odds ratios (95% confidence intervals) were 0.86 (0.71-1.04) for <1 time/week, 0.94 (0.78-1.13) for 1 time/week, and 0.76 (0.65-0.91) for ≥2 time/week. Similar results were observed when we use other cut-offs (SDS ≥ 40 and 50) to define depressive symptoms.

Conclusion: This study first demonstrated that the higher consumption of wholegrains might have effects on the prevention and improvement of depressive symptoms. Prospective or intervention studies are needed to confirm these findings.
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http://dx.doi.org/10.1038/s41430-021-00917-2DOI Listing
April 2021

Model-based evaluation of alternative reactive class closure strategies against COVID-19.

medRxiv 2021 Apr 23. Epub 2021 Apr 23.

There are contrasting results concerning the effect of reactive school closure on SARS-CoV-2 transmission. To shed light on this controversy, here we develop a data-driven computational model of SARS-CoV-2 transmission to investigate mechanistically the effect on COVID-19 outbreaks of school closure strategies based on syndromic surveillance and antigen screening of students. We found that by reactively closing classes based on syndromic surveillance, SARS-CoV-2 infections are reduced by no more than 13.1% (95%CI: 8.6%-20.2 %), due to the low probability of timely symptomatic case identification among the young population. We thus investigated an alternative triggering mechanism based on repeated screening of students using antigen tests. Should population-level social distancing measures unrelated to schools enable maintaining the reproduction number ( ) at 1.3 or lower, an antigen-based screening strategy is estimated to fully prevent COVID-19 outbreaks in the general population. Depending on the contribution of schools to transmission, this strategy can either prevent COVID-19 outbreaks for up to 1.9 or to at least greatly reduce outbreak size in very conservative scenarios about school contribution to transmission. Moving forward, the adoption of antigen-based screenings in schools could be instrumental to limit COVID-19 burden while vaccines continue to roll out through 2021, especially in light of possible continued emergence of SARS-CoV-2 variants.
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http://dx.doi.org/10.1101/2021.04.18.21255683DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8077629PMC
April 2021

A non-invasive model for predicting liver fibrosis in HBeAg-positive patients with normal or slightly elevated alanine aminotransferase.

Medicine (Baltimore) 2021 Apr;100(17):e25581

Department of Hepatology, Beijing University of Chinese Medicine Affiliated Shenzhen Hospital.

Abstract: Early and accurate diagnosis of liver fibrosis is necessary for HBeAg-positive chronic hepatitis B (CHB) patients with normal or slightly increased alanine aminotransferase (ALT), Liver biopsy and many non-invasive predicting markers have several application restrictions in grass-roots hospitals. We aimed to construct a non-invasive model based on routinely serum markers to predict liver fibrosis for this population.A total of 363 CHB patients with HBeAg-positive, ALT ≤2-fold the upper limit of normal and liver biopsy data were randomly divided into training (n = 266) and validation groups (n = 97). Two non-invasive models were established based on multivariable logistic regression analysis in the training group. Model 2 with a lower Akaike information criterion (AIC) was selected as a better predictive model. Receiver operating characteristic (ROC) was used to evaluate the model and was then independently validated in the validation group.The formula of Model 2 was logit (Model value) = 5.67+0.08 × Age -2.44 × log10 [the quantification of serum HBsAg (qHBsAg)] -0.60 × log10 [the quantification of serum HBeAg (qHBeAg)]+0.02 × ALT+0.03 ×  aspartate aminotransferase (AST). The area under the ROC curve (AUC) was 0.89 for the training group and 0.86 for the validation group. Using 2 cut-off points of -2.61 and 0.25, 59% of patients could be identified with liver fibrosis and antiviral treatment decisions were made without liver biopsies, and 149 patients were recommended to undergo liver biopsy for accurate diagnosis.In this study, the non-invasive model could predict liver fibrosis and may reduce the need for liver biopsy in HBeAg-positive CHB patients with normal or slightly increased ALT.
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http://dx.doi.org/10.1097/MD.0000000000025581DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8084058PMC
April 2021

Effects of polystyrene microplastic on uptake and toxicity of copper and cadmium in hydroponic wheat seedlings (Triticum aestivum L.).

Ecotoxicol Environ Saf 2021 Jul 13;217:112217. Epub 2021 Apr 13.

State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.

Microplastics are widespread in freshwater environments, their biological effects and combined effects of other pollutants have attracted extensive attention. In this study, we investigated the adsorption properties of heavy metals onto polystyrene (PS) microplastics as well as the bioavailability and toxicity of microplastics and heavy metals by hydroponic wheat seedlings experiment. Results showed that PS microplastics (0.5 µm, 100 mg/L) had no significant effect on wheat seedlings growth, photosynthesis, and reactive oxygen species (ROS) content. However, PS microplastics could adsorb copper and cadmium, with a predominantly chemisorption. The accumulation of copper and cadmium in wheat seedlings reduced in the presence of PS microplastics, which meant the toxic effect by heavy metals might be mitigated. Compared with single heavy metals treatments, the combination of PS microplastics and heavy metals increased chlorophyll content, enhanced photosynthesis and reduced the accumulation of ROS. These findings suggest that PS microplastics (0.5 µm, 100 mg/L) have a mitigating effect on the bioavailability and toxicity of copper and cadmium.
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http://dx.doi.org/10.1016/j.ecoenv.2021.112217DOI Listing
July 2021

Stock Market Liberalization and Corporate Green Innovation: Evidence from China.

Int J Environ Res Public Health 2021 03 25;18(7). Epub 2021 Mar 25.

The Center for Economic Research, Shandong University, Jinan 250100, China.

Corporate green innovation is an effective way to achieve energy conservation and emission reduction. Enterprises' willingness to pursue green innovation is increasingly affected by external factors. By using a quasi-natural experiment of China's Stock Connect program, we investigate the impact of stock market liberalization on corporate green innovation. We find that stock market liberalization increases enterprises' green innovation, especially for state-owned enterprises. We also find that stock market liberalization plays a stronger role in promoting the green invention patents of enterprises whose managers have overseas experience and enterprises in areas with a higher degree of openness. Our mechanism analysis suggests that stock market liberalization attracts the attention of securities analysts and increases managers' focus on environmental protection, thereby promoting corporate green innovation. Our findings show that stock market liberalization plays an important role in the governance of firms' non-financial behavior, which has important theoretical and practical implications.
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http://dx.doi.org/10.3390/ijerph18073412DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8037855PMC
March 2021

Comparison of new hyperspectral index and machine learning models for prediction of winter wheat leaf water content.

Plant Methods 2021 Mar 31;17(1):34. Epub 2021 Mar 31.

Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, #63 Nongye Road, Zhengzhou, 450002, Henan, People's Republic of China.

Background: The leaf water content estimation model is established by hyperspectral technology, which is crucial and provides technical reference for precision irrigation.

Methods: In this study, two consecutive years of field experiments (different irrigation times and seven wheat varieties) in 2018-2020 were performed to obtain the canopy spectra reflectance and leaf water content (LWC) data. The characteristic bands related to LWC were extracted from correlation coefficient method (CA) and x-Loading weight method (x-Lw). Five modeling methods, spectral index and four other methods (Partial Least-Squares Regression (PLSR), Random Forest Regression (RFR), Extreme Random Trees (ERT), and K-Nearest Neighbor (KNN)) based characteristic bands, were employed to construct LWC estimation models.

Results: The results showed that the canopy spectral reflectance increased with the increase of irrigation times, especially in the near-infrared band (750-1350 nm). The prediction accuracy of the newly developed differential spectral index DVI (R1185, R1307) was higher than that of the existing spectral index, with R of 0.85 and R of 0.78 for the calibration and validation, respectively. Due to a large amount of hyperspectral data, the correlation coefficient method (CA) and x-Loading weight (x-Lw) were used to select the water characteristic bands (100 and 28 characteristic bands, respectively) from the full spectrum. We found that the accuracy of the model based on the characteristic bands was not significantly lower than that of the full spectrum-based models. Among these models, the ERT- x-Lw model performed the best (R and RMSE of 0.88 and 1.46; 0.84 and 1.62 for the calibration and validation, respectively). In addition, the accuracy of the LWC estimation model constructed by ERT-x-Lw was higher than that of DVI (R1185, R1307).

Conclusion: The two models based on ERT-x-Lw and DVI (R1185, R1307) can effectively predict wheat leaf water content. The results provide a technical reference and a basis for crop water monitoring and diagnosis under similar production conditions.
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http://dx.doi.org/10.1186/s13007-021-00737-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8011113PMC
March 2021
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