Publications by authors named "Feng Rao"

77 Publications

Phase-Change-Memory Process at the Limit: A Proposal for Utilizing Monolayer SbTe.

Adv Sci (Weinh) 2021 Jul 14;8(13):2004185. Epub 2021 May 14.

Department of Physics, Applied Physics, and Astronomy Rensselaer Polytechnic Institute Troy NY 12180 USA.

One central task of developing nonvolatile phase change memory (PCM) is to improve its scalability for high-density data integration. In this work, by first-principles molecular dynamics, to date the thinnest PCM material possible (0.8 nm), namely, a monolayer SbTe, is proposed. Importantly, its SET (crystallization) process is a fast one-step transition from amorphous to hexagonal phase without the usual intermediate cubic phase. An increased spatial localization of electrons due to geometrical confinement is found to be beneficial for keeping the data nonvolatile in the amorphous phase at the 2D limit. The substrate and superstrate can be utilized to control the phase change behavior: e.g., with passivated SiO (001) surfaces or hexagonal Boron Nitride, the monolayer SbTe can reach SET recrystallization in 0.54 ns or even as fast as 0.12 ns, but with unpassivated SiO (001), this would not be possible. Besides, working with small volume PCM materials is also a natural way to lower power consumption. Therefore, the proposed PCM working process at the 2D limit will be an important potential strategy of scaling the current PCM materials for ultrahigh-density data storage.
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http://dx.doi.org/10.1002/advs.202004185DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8261487PMC
July 2021

Solidification of municipal solid waste incineration fly ash and immobilization of heavy metals using waste glass in alkaline activation system.

Chemosphere 2021 Jun 18;283:131240. Epub 2021 Jun 18.

School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, Hubei, 430070, China.

Hazardous heavy metals in Municipal Solid Waste Incineration (MSWI) fly ash are a threat to the environment and ecosystems. The objective of the work is to investigate the solidification of MSWI fly ash and the immobilization of the heavy metals through alkaline activation reaction with waste glass as an additive. Compressive strength measurement, X-ray diffraction (XRD), Si nuclear magnetic resonance spectroscopy (Si NMR) and scanning electron microscope (SEM) were performed to evaluate the solidification effect and characterize the microstructure of alkali-activated MSWI fly ash-based mortars. The leaching test, back-scattered electron microscopy (BSE) and X-ray photoelectron spectroscopy (XPS) were conducted to determine the heavy metals' immobilization effect and their immobilization forms. It was found that waste glass addition effectively reinforced the solidification of MSWI fly ash and immobilized the heavy metals. With 40% addition of waste glass, the compressive strength reached a maximum of 3.55 MPa. The immobilization efficiency of Cr increased with the addition of waste glass, while that of Cu, Pb, Zn and Cd is dependent on the eluant final pH, which decreased with the decrease of eluant final pH. The main immobilization forms include physical encapsulation, the formation of alkaline environment and the generation of silicate compounds.
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http://dx.doi.org/10.1016/j.chemosphere.2021.131240DOI Listing
June 2021

Time series prediction of COVID-19 transmission in America using LSTM and XGBoost algorithms.

Results Phys 2021 Aug 22;27:104462. Epub 2021 Jun 22.

School of Physical and Mathematical Sciences, Nanjing Tech University, Nanjing, Jiangsu 211816, China.

In this paper, we establish daily confirmed infected cases prediction models for the time series data of America by applying both the long short-term memory (LSTM) and extreme gradient boosting (XGBoost) algorithms, and employ four performance parameters as MAE, MSE, RMSE, and MAPE to evaluate the effect of model fitting. LSTM is applied to reliably estimate accuracy due to the long-term attribute and diversity of COVID-19 epidemic data. Using XGBoost model, we conduct a sensitivity analysis to determine the robustness of predictive model to parameter features. Our results reveal that achieving a reduction in the contact rate between susceptible and infected individuals by isolated the uninfected individuals, can effectively reduce the number of daily confirmed cases. By combining the restrictive social distancing and contact tracing, the elimination of ongoing COVID-19 pandemic is possible. Our predictions are based on real time series data with reasonable assumptions, whereas the accurate course of epidemic heavily depends on how and when quarantine, isolation and precautionary measures are enforced.
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http://dx.doi.org/10.1016/j.rinp.2021.104462DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8216863PMC
August 2021

IP-assisted CSN-COP1 competition regulates a CRL4-ETV5 proteolytic checkpoint to safeguard glucose-induced insulin secretion.

Nat Commun 2021 04 28;12(1):2461. Epub 2021 Apr 28.

School of Life Sciences, Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China.

COP1 and COP9 signalosome (CSN) are the substrate receptor and deneddylase of CRL4 E3 ligase, respectively. How they functionally interact remains unclear. Here, we uncover COP1-CSN antagonism during glucose-induced insulin secretion. Heterozygous Csn2 mice with partially disrupted binding of IP, a CSN cofactor, display congenital hyperinsulinism and insulin resistance. This is due to increased Cul4 neddylation, CRL4 E3 assembly, and ubiquitylation of ETV5, an obesity-associated transcriptional suppressor of insulin secretion. Hyperglycemia reciprocally regulates CRL4-CSN versus CRL4 assembly to promote ETV5 degradation. Excessive ETV5 degradation is a hallmark of Csn2, high-fat diet-treated, and ob/ob mice. The CRL neddylation inhibitor Pevonedistat/MLN4924 stabilizes ETV5 and remediates the hyperinsulinemia and obesity/diabetes phenotypes of these mice. These observations were extended to human islets and EndoC-βH1 cells. Thus, a CRL4-ETV5 proteolytic checkpoint licensing GSIS is safeguarded by IP-assisted CSN-COP1 competition. Deregulation of the IP-CSN-CRL4-ETV5 axis underlies hyperinsulinemia and can be intervened to reduce obesity and diabetic risk.
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http://dx.doi.org/10.1038/s41467-021-22941-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8080631PMC
April 2021

Corrigendum to "A PLK1 kinase inhibitor enhances the chemosensitivity of cisplatin by inducing pyroptosis in oesophageal squamous cell carcinoma" [EBioMedicine 41 (2019) 244-255].

EBioMedicine 2021 Jan 6;63:103041. Epub 2021 Jan 6.

Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, Beijing 100142, China. Electronic address:

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http://dx.doi.org/10.1016/j.ebiom.2020.103041DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7804599PMC
January 2021

Study on the fabrication and characterization of tip-loaded dissolving microneedles for transdermal drug delivery.

Eur J Pharm Biopharm 2020 Dec 12;157:66-73. Epub 2020 Oct 12.

College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China. Electronic address:

In order to increase the utilization rate of drug carried by microneedles and reduce waste, a two-step casting method was proposed to fabricate tip-loaded dissolving microneedles in this paper. The tip-loaded dissolving microneedles, also named layered microneedles, was consisted of two layers. The tip layer of the microneedles carried model drug, while the backing layer was fabricated with pure dissolving material. Polyvinyl alcohol, polyvinylpyrrolidone and hyaluronic acid were used as the base materials to fabricate the dissolving layers of the microneedle patches. Rhodamine B was chosen as the model drug to show the layered structure of tip-loaded microneedles. The material formulation and fabricating conditions of the tip-loaded dissolving microneedles and their transdermal insulin delivery efficiency were systematically studied. Nanoindentation testing showed that the tips of all three kinds of dissolving microneedles can bear the maximum loading of 50 mN with no damages, indicated sufficient mechanical strength for smooth skin puncturing as the minimum pressure required was 10 mN only. Moreover, our fabricated tip-loaded dissolving microneedles can greatly reduce the drug waste cause by unused backing layer in normal microneedles and realize a 30% enhancement of drug delivery efficiency after puncture treatment.
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http://dx.doi.org/10.1016/j.ejpb.2020.10.002DOI Listing
December 2020

Nutritional regulation influencing colony dynamics and task allocations in social insect colonies.

J Biol Dyn 2021 May 7;15(sup1):S35-S61. Epub 2020 Jul 7.

College of Integrative Sciences and Arts, USA Science and Mathematics Faculty, Arizona State University, Mesa, AZ, USA.

In this paper, we use an adaptive modeling framework to model and study how nutritional status (measured by the protein to carbohydrate ratio) may regulate population dynamics and foraging task allocation of social insect colonies. Mathematical analysis of our model shows that both investment to brood rearing and brood nutrition are important for colony survival and dynamics. When division of labour and/or nutrition are in an intermediate value range, the model undergoes a backward bifurcation and creates multiple attractors due to bistability. This bistability implies that there is a threshold population size required for colony survival. When the investment in brood is large enough or nutritional requirements are less strict, the colony tends to survive, otherwise the colony faces collapse. Our model suggests that the needs of colony survival are shaped by the brood survival probability, which requires good nutritional status. As a consequence, better nutritional status can lead to a better survival rate of larvae and thus a larger worker population.
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http://dx.doi.org/10.1080/17513758.2020.1786859DOI Listing
May 2021

Persistent oppression and simple decompression both exacerbate spinal cord ascorbate levels.

Int J Med Sci 2020 18;17(9):1167-1176. Epub 2020 May 18.

Department of Orthopaedics, Peking University Third Hospital, Beijing, China.

: Surgical decompression after acute spinal cord injury has become the consensus of orthopaedic surgeons. However, the choice of surgical decompression time window after acute spinal cord injury has been one of the most controversial topics in orthopaedics. : We apply an online electrochemical system (OECS) for continuously monitoring the ascorbate of the rats' spinal cord to determine the extent to which ascorbate levels were influenced by contusion or sustained compression. : Adult Sprague-Dawley rats (n=10) were instrumented for ascorbate concentration recording and received T11 drop spinal cord injury (SCI). The Group A (n=5) were treated with immediately decompression after SCI. The Group B (n=5) were contused and oppressed until 1 h after the injury to decompress. : The ascorbate level of spinal cord increased immediately by contusion injury and reached to 1.62 μmol/L ± 0.61 μmol/L (217.30% ± 95.09% of the basal level) at the time point of 60 min after the injury. Compared with the Group A, the ascorbate level in Group B increased more significantly at 1 h after the injury, reaching to 3.76 μmol/L ± 1.75 μmol/L (430.25% ± 101.30% of the basal level). Meanwhile, we also found that the decompression after 1 hour of continuous compression will cause delayed peaks of ascorbate reaching to 5.71 μmol/L ± 2.69 μmol/L (627.73% ± 188.11% of the basal level). : Our study provides first-hand direct experimental evidence indicating ascorbate is directly involved in secondary spinal cord injury and exhibits the dynamic time course of microenvironment changes after continuous compression injury of the spinal cord.
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http://dx.doi.org/10.7150/ijms.41289DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7294922PMC
March 2021

Suramin and NF449 are IP5K inhibitors that disrupt inositol hexakisphosphate-mediated regulation of cullin-RING ligase and sensitize cancer cells to MLN4924/pevonedistat.

J Biol Chem 2020 07 3;295(30):10281-10292. Epub 2020 Jun 3.

Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China

Inositol hexakisphosphate (IP) is an abundant metabolite synthesized from inositol 1,3,4,5,6-pentakisphosphate (IP) by the single IP 2-kinase (IP5K). Genetic and biochemical studies have shown that IP usually functions as a structural cofactor in protein(s) mediating mRNA export, DNA repair, necroptosis, 3D genome organization, HIV infection, and cullin-RING ligase (CRL) deneddylation. However, it remains unknown whether pharmacological perturbation of cellular IP levels affects any of these processes. Here, we performed screening for small molecules that regulate human IP5K activity, revealing that the antiparasitic drug and polysulfonic compound suramin efficiently inhibits IP5K and The results from docking experiments and biochemical validations suggested that the suramin targets IP5K in a distinct bidentate manner by concurrently binding to the ATP- and IP-binding pockets, thereby inhibiting both IP phosphorylation and ATP hydrolysis. NF449, a suramin analog with additional sulfonate moieties, more potently inhibited IP5K. Both suramin and NF449 disrupted IP-dependent sequestration of CRL by the deneddylase COP9 signalosome, thereby affecting CRL activity cycle and component dynamics in an IP5K-dependent manner. Finally, nontoxic doses of suramin, NF449, or NF110 exacerbate the loss of cell viability elicited by the neddylation inhibitor and clinical trial drug MLN4924/pevonedistat, suggesting synergistic ef-fects. Suramin and its analogs provide structural templates for designing potent and specific IP5K inhibitors, which could be used in combination therapy along with MLN4924/pevonedistat. IP5K is a potential mechanistic target of suramin, accounting for suramin's therapeutic effects.
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http://dx.doi.org/10.1074/jbc.RA120.014375DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7383383PMC
July 2020

Isothermal Coal-Based Reduction Kinetics of Fayalite in Copper Slag.

ACS Omega 2020 Apr 9;5(15):8605-8612. Epub 2020 Apr 9.

College of Zijin Mining, Fuzhou University, Fuzhou 350116, Fujian, PR China.

The coal-based reduction of fayalite was characterized using thermogravimetric (TG) and differential TG methods with reduction temperatures from 1123 to 1273 K. The results of fayalite isothermal reduction indicate that the reduction process is divided two stages. The corresponding apparent activation energy was gained using the isoconversional and model-fitting methods. At the first stage, the effect of temperature on the reduction degree was not clear, and the phase boundary chemical reaction was the controlling step, with an apparent activation energy value of 175.32-202.37 kJ·mol. At the second stage, when the temperature was more than 1123 K, the conversion degree and the reaction rate increased nonlinearly with increasing temperature, and two-dimensional diffusion, three-dimensional diffusion, one-dimensional diffusion, and phase boundary-controlled reaction were the controlling stages, with an apparent activation energy ranging from 194.81 to 248.96 kJ·mol. For the whole reduction process, the average activation energy and pre-exponential factor were 185.07-225.67 kJ·mol and 0.796-0.797 min, respectively.
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http://dx.doi.org/10.1021/acsomega.9b04497DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7178331PMC
April 2020

Effects of curing temperature on the compressive strength and microstructure of copper tailing-based geopolymers.

Chemosphere 2020 Aug 11;253:126754. Epub 2020 Apr 11.

Hubei Key Laboratory of Mineral Resources Processing and Environment, Luoshi Road 122, Wuhan, Hubei, 430070, China.

This study sought to analyze the effect of curing temperature on mechanical strength and microstructure of a copper tailing-based geopolymer via scanning electron microscopy (SEM), HCl extraction, nuclear magnetic resonance (NMR), and X-ray diffraction (XRD). The distribution of gel formed in geopolymers tended to be uniform with increasing curing temperature from 25 to 80 °C. Moreover, the percentage of Si sites in C-S-H and N-A-S-H gels increased from 62.08% to 78.94% and more tetrahedral [AlO] was incorporated into the tetrahedron [SiO] backbone, leading to an increase of compressive strength from 10.2 to 39.6 MPa. When the curing temperature was increased to 120 °C, the percentage of Si sites in C-S-H and N-A-S-H gel decreased to 69.52%, and the compressive strength decreased to 27.5 MPa. Moderately elevated curing temperature promoted the dissolution of aluminosilicate while curing temperatures above 80 °C hindered it. Excessive curing temperature led to a decrease in the geopolymer alkaline medium.
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http://dx.doi.org/10.1016/j.chemosphere.2020.126754DOI Listing
August 2020

Mechanical property and structural evolution of alkali-activated slag-phosphate mine tailings mortars.

Chemosphere 2020 Jul 27;251:126367. Epub 2020 Feb 27.

School of Zijin Mining, Fuzhou University, Fuzhou, Fujian, 350108, China; Fuzhou University-Zijin Mining Group Joint Research Center for Comprehensive Utilization of Mineral Resources, Fuzhou, Fujian, 350108, China. Electronic address:

The present work studies consolidation of phosphate mine tailings through alkaline activation process with the addition of slag for adjusting the gel structure. As increasing slag contents in the raw materials, more (Na,K)O-CaO-AlO-SiO-HO (C-A-S-H) and (Na,K)O-AlO-SiO-HO (N-A-S-H) gels were formed in the mine tailings-based mortars. Compressive strength of the mortars increased as increasing the slag contents from 0 to 40%, and then it kept a plateau. Evolution in microstructure of these mortars were characterized through scanning electron microscopy (SEM), X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) measurements. The study provides fundamentals for the co-disposal of phosphate mine tailings with blast furnace slag through alkaline activation process.
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http://dx.doi.org/10.1016/j.chemosphere.2020.126367DOI Listing
July 2020

Basis for metabolite-dependent Cullin-RING ligase deneddylation by the COP9 signalosome.

Proc Natl Acad Sci U S A 2020 02 11;117(8):4117-4124. Epub 2020 Feb 11.

Department of Biology, Southern University of Science and Technology, Shenzhen, 518055 Guangdong, China;

The Cullin-RING ligases (CRLs) are the largest family of ubiquitin E3s activated by neddylation and regulated by the deneddylase COP9 signalosome (CSN). The inositol polyphosphate metabolites promote the formation of CRL-CSN complexes, but with unclear mechanism of action. Here, we provide structural and genetic evidence supporting inositol hexakisphosphate (IP) as a general CSN cofactor recruiting CRLs. We determined the crystal structure of IP in complex with CSN subunit 2 (CSN2), based on which we identified the IP-corresponding electron density in the cryoelectron microscopy map of a CRL4A-CSN complex. IP binds to a cognate pocket formed by conserved lysine residues from CSN2 and Rbx1/Roc1, thereby strengthening CRL-CSN interactions to dislodge the E2 CDC34/UBE2R from CRL and to promote CRL deneddylation. IP binding-deficient knockin mice are embryonic lethal. The same mutation disabled Csn2 from rescuing UV-hypersensitivity of -null yeast. These data suggest that CRL transition from the E2-bound active state to the CSN-bound sequestered state is critically assisted by an interfacial IP small molecule, whose metabolism may be coupled to CRL-CSN complex dynamics.
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http://dx.doi.org/10.1073/pnas.1911998117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7049131PMC
February 2020

Aligned chitosan nanofiber hydrogel grafted with peptides mimicking bioactive brain-derived neurotrophic factor and vascular endothelial growth factor repair long-distance sciatic nerve defects in rats.

Theranostics 2020 1;10(4):1590-1603. Epub 2020 Jan 1.

Department of Orthopedics and Trauma, Peking University People's Hospital, Beijing100044, China.

Autologous nerve transplantation, which is the gold standard for clinical treatment of peripheral nerve injury, still has many limitations. In this study, aligned chitosan fiber hydrogel (ACG) grafted with a bioactive peptide mixture consisting of RGI (Ac-RGIDKRHWNSQGG) and KLT (Ac-KLTWQELYQLKYKGIGG), designated as ACG-RGI/KLT, was used as nerve conduit filler to repair sciatic nerve defects in rats. : Chitosan nanofiber hydrogel was prepared by a combination of electrospinning and mechanical stretching methods, and was then grafted with RGI and KLT, which are peptides mimicking brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF), respectively. The physicochemical properties of ACG-RGI/KLT were fully characterized. , the distribution, proliferation, and secretory activity of Schwann cells were analyzed. Next, the repair potential for 15-mm rat sciatic nerve defects was examined. The recovery of regenerated nerve, muscle, and motor function was evaluated by neuromuscular histology, electrophysiology, and catwalk gait analysis. : We first constructed directionally aligned chitosan nanofiber hydrogel grafted with RGI/KLT peptide mixture (ACG-RGI/KLT). ACG-RGI/KLT oriented the Schwann cells, and promoted the proliferation and secretion of neurotrophic factors by Schwann cells. At an early injury stage, ACG-RGI/KLT not only enhanced nerve regeneration, but also promoted vascular penetration. At 12 weeks, ACG-RGI/KLT facilitated nerve regeneration and functional recovery in rats. : Aligned chitosan nanofiber hydrogel grafted with RGI/KLT peptide provides an effective means of repairing sciatic nerve defects and shows great potential for clinical application.
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http://dx.doi.org/10.7150/thno.36272DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6993237PMC
April 2021

Cullin-RING Ligase Regulation by the COP9 Signalosome: Structural Mechanisms and New Physiologic Players.

Adv Exp Med Biol 2020 ;1217:47-60

Department of Biology, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Southern University of Science and Technology, Shenzhen, Guangdong, China.

The Cullin-RING E3 ligases (CRLs) are major ubiquitylation machineries regulated by reversible cycles of neddylation and deneddylation. The deneddylase COP9 Signalosome (CSN) terminates CRL catalytic cycle. CSN also provides a docking platform for several kinases and deubiquitinases that might play a role in regulating CRL. Recently, remarkable progress has been made in elucidating the biochemical principles and physiological implications of such exquisite regulation. The cryo-EM structures of CRL-CSN complexes provide the biochemical basis of their cognate interactions and reveal potential regulatory mechanisms during complex disassembly. Moreover, novel players beyond the canonical eight subunits of CSN were identified. This includes CSNAP, a potential 9th CSN subunit with regulatory functions, and the metabolite inositol hexakisphosphate (IP), which enhances CRL-CSN complex formation, with IP-metabolizing enzymes possibly instilling dynamics to the CRL-CSN system. Here, we review and summarize these new mechanistic insights along with progress in understanding CSN biology based on model organisms with genetically edited CSN subunits.
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http://dx.doi.org/10.1007/978-981-15-1025-0_4DOI Listing
February 2020

A persistent outbreak of varicella in a primary school in Dongguan City, Guangdong Province, China.

J Int Med Res 2020 Mar 27;48(3):300060519887847. Epub 2019 Nov 27.

Dongguan Municipal Center for Disease Control and Prevention, Dongguan City, Guangdong Province, People's Republic of China.

Objectives: To describe the epidemiological features of a school varicella outbreak in Dongguan City, China, to identify the reasons underlying persistent spread, and to assess the effectiveness of the varicella vaccine.

Methods: We identified all cases during the outbreak. We described the outbreak epidemic course and examined the influence of the following variables on the outbreak: sleeping in the dormitory, eating in school, taking school transportation, hand-washing habits, morning examinations, and effectiveness of case isolation. Logistic regression was used to estimate the odds ratio and 95% confidence interval (CI) of contracting varicella.

Results: A total of 92 varicella cases were reported, accounting for 5.53% (92/1663) of all students. Among cases, 64.13% (59/92) were vaccinated. The outbreak lasted for 93 days and occurred in six generations. Vaccination coverage was between 78.05% and 85.67%. The varicella vaccine was effective in 56.63% of recipients (95% CI: 35.49-70.84%). Vaccine effectiveness significantly decreased after 4-6 years.

Conclusions: The varicella vaccine was unable to prevent virus spread even with high vaccination coverage. Delayed and inefficient isolation of cases was the primary cause of the persistent outbreak.
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http://dx.doi.org/10.1177/0300060519887847DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7607272PMC
March 2020

Effects of aluminum on the expansion and microstructure of alkali-activated MSWI fly ash-based pastes.

Chemosphere 2020 Feb 27;240:124986. Epub 2019 Sep 27.

School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, Hubei, 430070, China. Electronic address:

Alkaline activation is of great potential in the solidification of municipal solid waste incineration (MSWI) fly ash, but the metallic aluminum in the ash inhibits its application. This work studies the effects of residual metallic aluminum on the expansion and microstructure of alkali-activated MSWI fly ash-based pastes. Based on the results obtained, an optimized preparation process is suggested. Characterizations of the pastes include expansion ratio, morphology (SEM), mechanical strength and microstructure (XRD and FTIR). It is confirmed that MSWI fly ash could be solidified through alkaline activation when using a small amount of coal fly ash to adjust the reactive silica and aluminum ratios. In the optimized preparation, sodium hydroxide was added separately, so that expansion in the pastes was significantly mitigated, the formation of geopolymer gel was improved and the compressive strength of the pastes increased.
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http://dx.doi.org/10.1016/j.chemosphere.2019.124986DOI Listing
February 2020

Enhanced removal of methyl orange on exfoliated montmorillonite/chitosan gel in presence of methylene blue.

Chemosphere 2020 Jan 27;238:124693. Epub 2019 Aug 27.

Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China.

In this work, self-assembled gels were prepared with exfoliated montmorillonite and chitosan (EMCG) as the adsorbent for removing methyl orange (MO) from water in absence and presence of methylene blue (MB). Several techniques including scanning electron microscope (SEM), zeta potential, fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used for the characterization of the EMCG before and after removal of MO. The EMCG performed well in the removal of MO attributing to the electrostatic attraction, cation exchange and hydrogen bond. The adsorption behaviors were followed pseudo-second-order and Langmuir isotherm. More surprisingly, the maximum adsorption capacity of MO was obviously enhanced in the presence of MB that it increased from 545 mg g (absence of MB) to 1060 mg g with the shielding effect of MB on EMCG which allowed MO and MB to alternately arrange at the adsorption sites. This finding of the synergistic effect between the two dyes on the proposed composite opens up new vistas to imagine the enhanced purification of the wastewater with multiple dyes co-existed using the multifunctional adsorbents.
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http://dx.doi.org/10.1016/j.chemosphere.2019.124693DOI Listing
January 2020

Phase-change heterostructure enables ultralow noise and drift for memory operation.

Science 2019 10 22;366(6462):210-215. Epub 2019 Aug 22.

Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.

Artificial intelligence and other data-intensive applications have escalated the demand for data storage and processing. New computing devices, such as phase-change random access memory (PCRAM)-based neuro-inspired devices, are promising options for breaking the von Neumann barrier by unifying storage with computing in memory cells. However, current PCRAM devices have considerable noise and drift in electrical resistance that erodes the precision and consistency of these devices. We designed a phase-change heterostructure (PCH) that consists of alternately stacked phase-change and confinement nanolayers to suppress the noise and drift, allowing reliable iterative RESET and cumulative SET operations for high-performance neuro-inspired computing. Our PCH architecture is amenable to industrial production as an intrinsic materials solution, without complex manufacturing procedure or much increased fabrication cost.
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http://dx.doi.org/10.1126/science.aay0291DOI Listing
October 2019

Are Inositol Polyphosphates the Missing Link in Dynamic Cullin RING Ligase Regulation by the COP9 Signalosome?

Biomolecules 2019 08 7;9(8). Epub 2019 Aug 7.

Department of Biology, Institute of Neuroscience, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Southern University of Science and Technology, Shenzhen 518055, China.

The E3 ligase activity of Cullin RING Ligases (CRLs) is controlled by cycles of neddylation/deneddylation and intimately regulated by the deneddylase COP9 Signalosome (CSN), one of the proteasome lid-CSN-initiation factor 3 (PCI) domain-containing "Zomes" complex. Besides catalyzing the removal of stimulatory Cullin neddylation, CSN also provides a docking platform for other proteins that might play a role in regulating CRLs, notably protein kinases and deubiquitinases. During the CRL activity cycle, CRL-CSN complexes are dynamically assembled and disassembled. Mechanisms underlying complex dynamics remain incompletely understood. Recently, the inositol polyphosphate metabolites (IP6, IP7) and their metabolic enzymes (IP5K, IP6K) have been discovered to participate in CRL-CSN complex formation as well as stimulus-dependent dissociation. Here we discuss these mechanistic insights in light of recent advances in elucidating structural basis of CRL-CSN complexes.
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http://dx.doi.org/10.3390/biom9080349DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6722667PMC
August 2019

Conjugated System of PEDOT:PSS-Induced Self-Doped PANI for Flexible Zinc-Ion Batteries with Enhanced Capacity and Cyclability.

ACS Appl Mater Interfaces 2019 Aug 13;11(34):30943-30952. Epub 2019 Aug 13.

College of Materials Science and Engineering , Shenzhen University , Shenzhen 518055 , China.

Owing to its electronic conductivity and electrochemical reactivity, polyaniline (PANI) can serve as the cathode for rechargeable zinc-ion batteries (ZIBs). However, it suffers from fast deactivation and thus performance deterioration because of spontaneous deprotonation during charge/discharge. Here, we report an effective strategy to improve the electrochemical reactivity and stability of the PANI-based cathode by constructing a π-electron conjugated system between PANI and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) on carbon nanotubes (CNTs). The impressive performance of the post-treated CNTs-PANI-PEDOT:PSS (t-CNTs-PA-PE) cathode is largely attributed to the -SOH groups in PSS, which acts as an internal proton reservoir and provides enough H for PANI's protonation, thus promoting its electrochemical activity and reversibility. Besides, the strong interactions between PANI and PEDOT:PSS assist the stretching of π-π conjugation chains, bringing about enhanced electronic conductivity. Consequently, the t-CNTs-PA-PE cathode achieves a high capacity of 238 mA h g, together with good rate capability and long-term stability (over 1500 cycles with 100% Coulombic efficiency). Through exerting the freestanding t-CNTs-PA-PE, a flexible ZIB was further constructed with both outstanding electrochemical properties and superior high safety. This work demonstrates the availability of conducting polymer cathodes for high-performance ZIBs, fulfilling the need of flexible electronics.
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http://dx.doi.org/10.1021/acsami.9b09802DOI Listing
August 2019

Catching structural transitions in liquids.

Science 2019 06;364(6445):1032-1033

Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.

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http://dx.doi.org/10.1126/science.aax6333DOI Listing
June 2019

Exosomes from Human Gingiva-Derived Mesenchymal Stem Cells Combined with Biodegradable Chitin Conduits Promote Rat Sciatic Nerve Regeneration.

Stem Cells Int 2019 2;2019:2546367. Epub 2019 May 2.

Department of Orthopedics and Trauma, Peking University People's Hospital, Beijing, China.

At present, repair methods for peripheral nerve injury often fail to get satisfactory result. Although various strategies have been adopted to investigate the microenvironment after peripheral nerve injury, the underlying molecular mechanisms of neurite outgrowth remain unclear. In this study, we evaluate the effects of exosomes from gingival mesenchymal stem cells (GMSCs) combined with biodegradable chitin conduits on peripheral nerve regeneration. GMSCs were isolated from human gingival tissue and characterized by surface antigen analysis and in vitro multipotent differentiation. The cell supernatant was collected to isolate the exosomes. The exosomes were characterized by transmission electron microscopy, Western blot, and size distribution analysis. The effects of exosomes on peripheral nerve regeneration in vitro were evaluated by coculture with Schwann cells and DRGs. The chitin conduit was prepared and combined with the exosomes to repair rat sciatic nerve defect. Histology, electrophysiology, and gait analysis were used to test the effects of exosomes on sciatic nerve function recovery in vivo. We have successfully cultured GMSCs and isolated exosomes. The exosomes from GMSCs could significantly promote Schwann cell proliferation and DRG axon growth. The in vivo studies showed that chitin conduit combined with exosomes from GMSCs could significantly increase the number and diameter of nerve fibers and promote myelin formation. In addition, muscle function, nerve conduction function, and motor function were also obviously recovered. In summary, this study suggests that GMSC-derived exosomes combined with biodegradable chitin conduits are a useful and novel therapeutic intervention in peripheral nerve repair.
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http://dx.doi.org/10.1155/2019/2546367DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6525800PMC
May 2019

Small-Molecule SB216763-Loaded Microspheres Repair Peripheral Nerve Injury in Small Gap Tubulization.

Front Neurosci 2019 15;13:489. Epub 2019 May 15.

Department of Orthopedics and Trauma, Peking University People's Hospital, Beijing, China.

Peripheral nerve injury has yet to be fully resolved because of its complicated pathological process. SB216763 is a small molecular compound that can enhance the remyelination of peripheral nerves by inhibiting glycogen synthase kinase-3β (GSK3β). GSK-3β inhibitor stimulates myelin gene expression and restores the myelin structure. Herein, we presented the effect of integrating small gap tubulization with SB216763-loaded microspheres by using a chitosan conduit. , SB216763 could promote neurite growth of dorsal root ganglia. studies showed that SB216763 increased the number of myelinated axons and the thickness of myelin sheaths. Electrophysiological examination and sciatic functional index results also indirectly indicated the role of SB216763 in repairing peripheral nerve injury. SB216763 promoted the recovery of muscle function. Therefore, combining SB216763-loaded PLGA microspheres with conduit small gap tubulization shows potential for applications in repairing peripheral nerve injury.
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http://dx.doi.org/10.3389/fnins.2019.00489DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6530511PMC
May 2019

Corrigendum to "A PLK1 kinase inhibitor enhances the chemosensitivity of cisplatin by inducing pyroptosis in oesophageal squamous cell carcinoma" [EBioMedicine 41 (2019) 244-255].

EBioMedicine 2019 05 14;43:650. Epub 2019 May 14.

Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, Beijing 100142, China. Electronic address:

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http://dx.doi.org/10.1016/j.ebiom.2019.05.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6558293PMC
May 2019

Expanded 3D nanofibre sponge scaffolds by gas-foaming technique enhance peripheral nerve regeneration.

Artif Cells Nanomed Biotechnol 2019 Dec;47(1):491-500

a Department of Orthopedics and Trauma , Peking University People's Hospital , Beijing , China.

Peripheral nerve injury has troubled clinical doctors for many years. To obtain better function recovery of peripheral nerve repair at the base of hollow nerve guidance conduit (NGC), many NGCs with fillers were developed in the application of tissue-engineered nerve graft. In this study, expanded 3D nanofibre sponge scaffolds with orientation and porosity were first fabricated by electrospinning and gas-foaming technique. Polylactic acid (PLA)/silk fibroin nanofibre sponge scaffolds were prepared as filler to construct 3D nanofibre sponges containing NGC (SNGC). SNGC could promote the proliferation of Schwann cells compared with the hollow NGC in vitro. The results of animal experiments confirm that SNGC can significantly promote peripheral nerve function recovery from histology and function evaluation. In conclusion, we design a new method to construct a 3D scaffold containing NGC with orientation and porosity. The application of this 3D scaffold material has good prospects in future peripheral nerve repair.
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http://dx.doi.org/10.1080/21691401.2018.1557669DOI Listing
December 2019

A PLK1 kinase inhibitor enhances the chemosensitivity of cisplatin by inducing pyroptosis in oesophageal squamous cell carcinoma.

EBioMedicine 2019 Mar 12;41:244-255. Epub 2019 Mar 12.

Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, Beijing 100142, China. Electronic address:

Background: Targeting PLK1 has recently been proven as a viable therapeutic strategy against oesophageal squamous cell carcinom (ESCC). Therefore, this study aimed to explore whether the PLK1 inhibitor BI2536 is able to sensitize ESCC cells to cisplatin (DDP) and determine the underlying mechanisms.

Methods: Viability, clonogenicity, cell cycle distribution and apoptosis were assessed in ESCC cells treated with BI2536 or DDP alone or in combination. Checkpoint activation was examined by immunoblotting and immunohistochemistry. Xenograft model was used to assess the efficacy of the co-treatment. The expression level of GSDME in tissue samples were examined by immunohistochemistry.

Findings: We found that the combination of BI2536 and DDP was synergistic in ESCC cells, which induced pyroptosis in ESCC cells at low doses. Mechanistic studies revealed that BI2536 significantly induced DNA damage and impaired the DNA damage repair pathway in DDP-treated cells both in vitro and in vivo. Interestingly, we found that co-treatment with BI2536 and DDP induced pyroptosis in ESCC cells depending on the caspase-3/GSDME pathway. Importantly, our study found that GSDME was more highly expressed in tumour tissue than that in normal adjacent tissues, and could serve as a prognostic factor.

Interpretation: BI2536 sensitizes ESCC cells to DDP by inhibiting the DNA damage repair pathway and inducing pyroptosis, which provides new information for understanding pyroptosis. Our study also reveals that the PLK1 inhibitor BI2536 may be an attractive candidate for ESCC targeted therapy, especially when combined with DDP for treating the GSDME overexpression subtype. FUND: National 973 Program and National Natural Science Fundation of China.
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http://dx.doi.org/10.1016/j.ebiom.2019.02.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6442225PMC
March 2019

Boosting the Yield of MXene 2D Sheets via a Facile Hydrothermal-Assisted Intercalation.

ACS Appl Mater Interfaces 2019 Feb 12;11(8):8443-8452. Epub 2019 Feb 12.

College of Materials Science and Engineering , Shenzhen University , Shenzhen 518055 , China.

TiCT (MXene) exhibits attractive properties in different applications. However, traditional synthesis leads to unsatisfactory yield of two-dimensional (2D) TiCT , e.g., lower than 20%, which stems from the strong interactions of potential Ti-Ti bonds and residual Ti-Al bonds between the adjacent TiC layers, hindering the effective intercalation and delamination. Herein, we propose a facile hydrothermal-assisted intercalation (HAI) strategy to boost the yield of 2D sheets, achieving a record high value of 74%. This HAI assists the diffusion and intercalation of reagent effectively, promoting the subsequent delamination; meanwhile, an antioxidant is applied to protect these TiCT from oxidation during the HAI process. Therefore, massive TiCT 2D sheets can be easily synthesized. Thanks to the synergistic effect of high conductivity and substantial terminated functionalities, these TiCT 2D sheets show promising application in supercapacitor, providing a high capacitance of 482 F g. Besides, the ultrafast carrier dynamics results of TiCT 2D sheets clearly imply the promising application in photocatalysis due to the relatively long bleaching relaxation time. Our work not only paves the way for the mass production of TiCT 2D sheets but also provides insights into their electronic and optical properties.
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http://dx.doi.org/10.1021/acsami.8b22339DOI Listing
February 2019

Pb(ΙΙ) removal from water using porous hydrogel of chitosan-2D montmorillonite.

Int J Biol Macromol 2019 May 23;128:85-93. Epub 2019 Jan 23.

School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070, China; Hubei Provincial Collaborative Innovation Center for High Efficient Utilization of Vanadium Resources, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070, China. Electronic address:

An eco-friendly chitosan-2D montmorillonite (CTS/2DMMT) hydrogel with the characteristics of high surface area, porous structure and easy separation as a new type of adsorbent was investigated. Hydrogel was prepared via self-assembling 2DMMT and CTS. 2DMMT and hydrogel were characterized by particle size analysis, SEM and AFM, respectively. The results showed the 2DMMT was well exfoliated and the porosity of hydrogel's structure could be adjusted by the CTS/2DMMT ratio. The effect of pH, adsorption kinetics and adsorption isotherm of Pb(ΙΙ) from aqueous solution onto hydrogels were investigated. Adsorption could proceed without the pH adjustment and hydrogel with a looser structure has better adsorption effectiveness. The Pseudo-first-order kinetics model and Freundlich isotherm model could fit well with the Pb(ΙΙ) adsorption process onto hydrogel. The adsorption mechanism was the ion-exchange according to the analysis of XPS and EDS.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.01.098DOI Listing
May 2019
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