The appendix for dynamic model of respiratory infectious disease transmission by population mobility based on city network

In modern societies, newly emerging infectious diseases spread rapidly between regions owing to frequent contact between people, causing considerable social and economic impacts. In this study, first, a scale-free city network was established, and then the shortest path between any two nodes was determined. Second, the movement path of tourists was designed based on the shortest path. Subsequently, every infected person's information, such as the city, infection time, onset and hospitalization, was confirmed based on their movement path. Third, the features of the transmission path and time distribution of the epidemic were characterized after summarizing the information. Finally, the reliability of the model was verified. The number of citizens and tourists in every city remained stable during this time. The results indicated that a larger basic reproduction number (R0) and population outflow rate signify a faster growth rate of infected people in each city in the network. Compared with small and medium-sized cities, the epidemic spread faster in central cities. Population mobility was the decisive factor causing the spread of the epidemic to other areas. Therefore, the rapid spread of epidemics can be prevented by swiftly reducing the flow of people between cities

Pattern Investigation and Quantitative Analysis of Lithium Plating under Subzero Operation of Lithium-Ion Batteries

Safety hazards arising from lithium (Li) plating during the operation of lithium-ion batteries (LIBs) are a constant concern. Herein, this work explores the coaction of low temperatures and current rates (C rates) on Li plating in LIBs by electrochemical tests, material characterization, and numerical analysis. With a decrease in temperature and an increase in C rate, the battery charging process shifts from normal intercalation to Li plating and even ultimately fails at −20 °C and 0.5C. The morphology observations reveal the detailed growth process of individual plated Li through sand-like Li, whisker Li, dendritic Li, mossy Li, and finally bulk Li, as well as aggregated Li from sparse to dense. Through quantitative analysis, the dynamic pattern under long-term cycles is revealed. The low temperature and high C rate will lead to an increase in Li plating capacity and irreversibility, which are further deteriorated with the cycles. In addition, a critical condition of high Li plating and high reversibility at −10 °C and 0.2C is found, and further studies are needed to reveal the competition between kinetics and thermodynamics in the Li plating process. This work provides detailed information on the range and growth process of Li plating and quantifies Li plating, which can be used for practical Li plating prediction and regulation

Pattern Investigation and Quantitative Analysis of Lithium Plating under Subzero Operation of Lithium-Ion Batteries

Safety hazards arising from lithium (Li) plating during the operation of lithium-ion batteries (LIBs) are a constant concern. Herein, this work explores the coaction of low temperatures and current rates (C rates) on Li plating in LIBs by electrochemical tests, material characterization, and numerical analysis. With a decrease in temperature and an increase in C rate, the battery charging process shifts from normal intercalation to Li plating and even ultimately fails at −20 °C and 0.5C. The morphology observations reveal the detailed growth process of individual plated Li through sand-like Li, whisker Li, dendritic Li, mossy Li, and finally bulk Li, as well as aggregated Li from sparse to dense. Through quantitative analysis, the dynamic pattern under long-term cycles is revealed. The low temperature and high C rate will lead to an increase in Li plating capacity and irreversibility, which are further deteriorated with the cycles. In addition, a critical condition of high Li plating and high reversibility at −10 °C and 0.2C is found, and further studies are needed to reveal the competition between kinetics and thermodynamics in the Li plating process. This work provides detailed information on the range and growth process of Li plating and quantifies Li plating, which can be used for practical Li plating prediction and regulation

Photocurrent Response in Multiwalled Carbon Nanotube Core–Molybdenum Disulfide Shell Heterostructures

In this report, a few-layer molybdenum disulfide (MoS₂) shell was coated on core multiwalled carbon nanotube (CNT) by a facile solvothermal method. The morphology and high crystallinity of this structure were demonstrated and verified by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). After being integrated into a planar device, the CNT–MoS₂ core–shell structure exhibits clear photoresponse and a wide response range upon laser illumination. In addition, the device shows a bias-dependent and position-sensitive photocurrent effect. Further experiments show that larger photocurrent was obtained under laser illumination with longer wavelength. Both the photocurrent and response speed are enhanced when the device is placed under vacuum condition. The simple material synthesis and device fabrication method used in this work may provide a practical strategy for low-cost and large-scale optical applications

Monodispersed Ru Nanoparticles Functionalized Graphene Nanosheets as Efficient Cathode Catalysts for O₂‑Assisted Li–CO₂ Battery

In Li–CO₂ battery, due to the highly insulating nature of the discharge product of Li₂CO₃, the battery needs to be charged at a high charge overpotential, leading to severe cathode and electrolyte instability and hence poor battery cycle performance. Developing efficient cathode catalysts to effectively reduce the charge overpotential represents one of key challenges to realize practical Li–CO₂ batteries. Here, we report the use of monodispersed Ru nanoparticles functionalized graphene nanosheets as cathode catalysts in Li–CO₂ battery to significantly lower the charge overpotential for the electrochemical decomposition of Li₂CO₃. In our battery, a low charge voltage of 4.02 V, a high Coulomb efficiency of 89.2%, and a good cycle stability (67 cycles at a 500 mA h/g limited capacity) are achieved. It is also found that O₂ plays an essential role in the discharge process of the rechargeable Li–CO₂ battery. Under the pure CO₂ environment, Li–CO₂ battery exhibits negligible discharge capacity; however, after introducing 2% O₂ (volume ratio) into CO₂, the O₂-assisted Li–CO₂ battery can deliver a high capacity of 4742 mA h/g. Through an in situ quantitative differential electrochemical mass spectrometry investigation, the final discharge product Li₂CO₃ is proposed to form via the reaction 4Li⁺ + 2CO₂ + O₂ + 4e^– → 2Li₂CO₃. Our results validate the essential role of O₂ and can help deepen the understanding of the discharge and charge reaction mechanisms of the Li–CO₂ battery

Nuclear PTEN tumor-suppressor functions through maintaining heterochromatin structure

<p>The tumor suppressor, PTEN, is one of the most commonly mutated genes in cancer. Recently, PTEN has been shown to localize in the nucleus and is required to maintain genomic stability. Here, we show that nuclear PTEN, independent of its phosphatase activity, is essential for maintaining heterochromatin structure. Depletion of PTEN leads to loss of heterochromatic foci, decreased chromatin compaction, overexpression of heterochromatic genes, and reduced protein stability of heterochromatin protein 1 α. We found that the C-terminus of PTEN is required to maintain heterochromatin structure. Additionally, cancer-associated PTEN mutants lost their tumor-suppressor function when their heterochromatin structure was compromised. We propose that this novel role of PTEN accounts for its function in guarding genomic stability and suppressing tumor development.</p

ChIP assays to demonstrate that ETS-1, CREB, AP-2α and SP-1 bind to PP-2α promoter.

<p>ChIP assays were conducted as we recently described <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007019#pone.0007019-Qin1" target="_blank">[34]</a>. The oligos used for ChIP assays were described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007019#s2" target="_blank">Materials and Methods</a>. A. ChIP assays to show that ETS-1 and CREB bind to PP-2Aα promoter. Lane 1, DNA marker; lane 2, PCR product derived from 1/50 DNA template immunoprecipitated by anti-CREB antibody; Lane 3, PCR product derived from DNA template immunoprecipitated by normal IgG; lane 4, PCR product derived from 1/50 DNA template immunoprecipitated by anti-ETS-1 antibody; Lane 5, PCR product derived from DNA template immunoprecipitated by normal IgG; lane 6, PCR product derived from direct input DNA template without immunoprecipitation. A band of 189 bp containing both CREB and ETS-1 binding sites in the PP2A-Aα promoter gene was amplified. ChIP assay confirms that CREB and ETS-1 bind to PP2A-Aα gene. B. ChIP assays to show that AP-2α and SP-1 bind to PP-2Aα promoter. Lane 1, DNA marker; lane 2, PCR product derived from 1/50 DNA template immunoprecipitated by anti-SP-1 antibody; Lane 3, PCR product derived from DNA template immunoprecipitated by normal IgG; lane 4, PCR product derived from 1/50 DNA template immunoprecipitated by anti-AP-2α antibody; Lane 5, PCR product derived from DNA template immunoprecipitated by normal IgG; lane 6, PCR product derived from direct input DNA template without immunoprecipitation. A band of 168 bp containing both AP-2α and SP-1 binding sites in the PP2A-Aα promoter gene was amplified. ChIP assays confirm that AP-2α and SP-1 bind to PP2A-Aα gene.</p

Identification of the major <i>cis</i>-elements in the proximal promoter of the PP2A-Aα gene.

<p>A. Identification of the four putative <i>cis</i>-elements: ETS-1, CREB, AP-2α and SP-1 in the proximal promoter of the PP2A-Aα gene. The 677 bp DNA sequence (from +52 to −625) was analyzed with TFSEARCH and TESS two softwares. Four conserved <i>cis</i>-elements (marked below the sequence) were discovered. In the core promoter region of the PP2A-Aα gene, a putative TFIIB recognition element (BRE) and a putative downstream promoter element (DPE) are observed. However, the core promoter of the PP2A-Aα gene lacks TATA-box. The transcription initiation site was assigned according to the reported results. B. Western blot analysis of PP2A-Aα and the four cognate transcriptional factors (ETS-1, CREB, AP-2α and SP-1) in two ocular cell lines, retinal epithelial cells (ARPE-19) and the embryonic lens epithelial cells (FHL124).</p

Identification of the proximal PP2A-Aα promoter.

<p>A. Diagrams of 6 different constructs of the PP2A-Aα promoter linked to the luciferase reporter gene. Genomic DNA was extracted from mouse muscle and used for PCR amplification of the PP2A-Aα promoter fragments (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007019#s2" target="_blank">methods</a> for details). To identify the proximal promoter, 7 oligo primers (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007019#pone-0007019-t001" target="_blank">Table 1</a>) were designed, synthesized and used for PCR. The amplified 6 DNA fragments were digested and then inserted into the basic luciferase reporter construct to generate A1 to A6 constructs. B. Relative luciferase activities derived from 6 different PP2A-Aα gene promoter constructs. Two µg of A1 A2, A3, A4, A5 or A6 construct of the luciferase reporter gene and 20 ng internal control plasmid PhRL-sv40 were introduced into mouse lens epithelial αTN4-1 cells (Open bars) and human lens epithelial FHL124 cells (solid bars) in 12-well culture plates using lipofectamine 2000. After 24 hours, the luciferase activities from each testing construct and also from the internal control plasmid were measured using dual-luciferase reporter assay system from Promega Inc. The relative luciferase activity was determined by dividing the luciferase activity from the testing construct by that from the control plasmid. The ratio of A1 activity is assumed as 100%, then the activity of each of the five constructs were calculated using A1 as reference. Note that the construct A5 displays similar luciferase activity to A3 and A4, suggesting that this construct contains the proximal promoter of the PP2A-Aα gene.</p

Demonstration that ETS-1 regulates the PP2A-Aα promoter.

<p>A. Wild type or mutant ETS-1 oligos used for gel mobility shifting assays described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007019#pone-0007019-g003" target="_blank">Fig. 3B</a>. B. Gel mobility shifting demonstrates that ETS-1 from both ARPE-19 (Lane 1 to 5) and FHL124 (Lane 6 to 10) binds to the oligo containing the wild type ETS-1 binding site. Nuclear extracts prepared from both types of cells were incubated with γ-³²P-ATP-labeled oligos containing wild-type ETS-1 binding site under various conditions shown in the figure. The reaction mixtures were then separated with 5% native PAGE. The gel was dried and exposed to X-ray film for overnight. Lane 1, gel mobility shifting assays with labeled oligo containing wild-type ETS-1 binding site and ARPE-19 nuclear extract. Lane 2, the same assay as in lane 1 except that 50-fold of non-labeled wild-type ETS-1 oligos was added into the reaction. Note that the ETS-1 complex was competed off. Lane 3, the same assay as in lane 1 except that the non-labeled competing oligo contains a mutated ETS-1 binding site (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007019#pone-0007019-g003" target="_blank">Fig. 3A</a>, bottom), which showed only slight competition ability. Lane 4, the same assay as in lane 1 except that normal IgG was used for mock supershifting assay. Lane 5, the same assay as in lane 1 except that anti-ETS-1 antibody was added for supershifting assay. Note that addition of anti-ETS-1 antibody into the reaction led to formation of the supershifting ETS-1 complex. Lane 6 to Lane 10, the same order as in Lane 1 to Lane 5 except that the nuclear extracts were from the FHL124 cells. C to E. Demonstration of the relative importance of the ETS-1 binding site in regulating the PP2A-Aα promoter. C. Mutation of the ETS-1 binding site in the PP2A-Aα promoter causes an approximately 60% loss of the luciferase reporter gene activity in both types of ocular cells. The P value was calculated by comparing the activity difference between the mutant promoter with the wild type promoter in the same type of cell. D. Expression of the exogenous ETS-1 in both types of ocular cells induces dose-dependent increase in the luciferase reporter gene activity within 0 to 500 ng of the pCMV-ETS-1 plasmid. The P value was calculated by comparing the luciferase difference between the vector (pCI-Neo) co-expression and the co-expression of each concentration of exogenous Ets-1 plasmid (50, 100 and 500 ng) with the wild type promoter in the same type of cell. E. Expression of the exogenous ETS-1 in both types of ocular cells enhanced expression of the endogenous gene coding for PP2A-Aα. Transfection and luciferase activity assays were conducted as previously described <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007019#pone.0007019-Yan2" target="_blank">[29]</a>.</p