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1.
Artigo em Inglês | MEDLINE | ID: mdl-33522787

RESUMO

The large-area preparation of excellent lubricating materials with good resistance to leakage and an oxidation atmosphere and ease of replenishment has remained a challenge. Here, inspired by the Nepenthes pitcher slippery surface, we have fabricated multifunctional lubricant-infused surfaces (LISs) via a scalable technique, in which the solid lubricants and the lubricant oil are reciprocally well-combined to overcome their respective weakness. The designed LIS coating exhibits a multiple lubrication ability with a coefficient of friction of 0.022 and ball wear rate of 2.62 × 10-18 m3·N-1·m-1 in air, which are 21 times and three orders of magnitude lower than those of the steel-steel contact under macroscale test conditions (10 N, 5 Hz), respectively. In addition, the outstanding water-repellent and self-cleaning LIS coating enables the resistance to the strong acid or base corrosion even after 30 days of immersion, and the excellent anticorrosion performance during the electrochemical corrosion test. With the exceptional lubrication, multifunctionality performance, and large-scale fabrication capacity, the prepared LIS coating should find potential applications in machines, pipelines, navigation, infrastructures, outdoor equipment, and so on.

2.
Parasit Vectors ; 14(1): 41, 2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-33430945

RESUMO

BACKGROUND: Despite the licensure of the world's first dengue vaccine and the current development of additional vaccine candidates, successful Aedes control remains critical to the reduction of dengue virus transmission. To date, there is still limited literature that attempts to explain the spatio-temporal population dynamics of Aedes mosquitoes within a single city, which hinders the development of more effective citywide vector control strategies. Narrowing this knowledge gap requires consistent and longitudinal measurement of Aedes abundance across the city as well as examination of relationships between variables on a much finer scale. METHODS: We utilized a high-resolution longitudinal dataset generated from Singapore's islandwide Gravitrap surveillance system over a 2-year period and built a Bayesian hierarchical model to explain the spatio-temporal dynamics of Aedes aegypti and Aedes albopictus in relation to a wide range of environmental and anthropogenic variables. We also created a baseline during our model assessment to serve as a benchmark to be compared with the model's out-of-sample prediction/forecast accuracy as measured by the mean absolute error. RESULTS: For both Aedes species, building age and nearby managed vegetation cover were found to have a significant positive association with the mean mosquito abundance, with the former being the strongest predictor. We also observed substantial evidence of a nonlinear effect of weekly maximum temperature on the Aedes abundance. Our models generally yielded modest but statistically significant reductions in the out-of-sample prediction/forecast error relative to the baseline. CONCLUSIONS: Our findings suggest that public residential estates with older buildings and more nearby managed vegetation should be prioritized for vector control inspections and community advocacy to reduce the abundance of Aedes mosquitoes and the risk of dengue transmission.

3.
BMC Med ; 18(1): 399, 2020 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-33327961

RESUMO

BACKGROUND: Zika virus (ZIKV) emerged as a global epidemic in 2015-2016 from Latin America with its true geographical extent remaining unclear due to widely presumed underreporting. The identification of locations with potential and unknown spread of ZIKV is a key yet understudied component for outbreak preparedness. Here, we aim to identify locations at a high risk of cryptic ZIKV spread during 2015-2016 to further the understanding of the global ZIKV epidemiology, which is critical for the mitigation of the risk of future epidemics. METHODS: We developed an importation simulation model to estimate the weekly number of ZIKV infections imported in each susceptible spatial unit (i.e. location that did not report any autochthonous Zika cases during 2015-2016), integrating epidemiological, demographic, and travel data as model inputs. Thereafter, a global risk model was applied to estimate the weekly ZIKV transmissibility during 2015-2016 for each location. Finally, we assessed the risk of onward ZIKV spread following importation in each susceptible spatial unit to identify locations with a high potential for cryptic ZIKV spread during 2015-2016. RESULTS: We have found 24 susceptible spatial units that were likely to have experienced cryptic ZIKV spread during 2015-2016, of which 10 continue to have a high risk estimate within a highly conservative scenario, namely, Luanda in Angola, Banten in Indonesia, Maharashtra in India, Lagos in Nigeria, Taiwan and Guangdong in China, Dakar in Senegal, Maputo in Mozambique, Kinshasa in Congo DRC, and Pool in Congo. Notably, among the 24 susceptible spatial units identified, some have reported their first ZIKV outbreaks since 2017, thus adding to the credibility of our results (derived using 2015-2016 data only). CONCLUSION: Our study has provided valuable insights into the potentially high-risk locations for cryptic ZIKV circulation during the 2015-2016 pandemic and has also laid a foundation for future studies that attempt to further narrow this key knowledge gap. Our modelling framework can be adapted to identify areas with likely unknown spread of other emerging vector-borne diseases, which has important implications for public health readiness especially in resource-limited settings.

4.
J Travel Med ; 2020 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-32841354

RESUMO

BACKGROUND: With more countries exiting lockdown, public health safety requires screening measures at international travel entry points which can prevent the reintroduction or importation of the SARS-CoV-2 virus. Here, we estimate the number of cases captured, quarantining days averted and secondary cases expected to occur with screening interventions. METHODS: To estimate active case exportation risk from 153 countries with recorded COVID-19 cases and deaths, we created a simple data-driven framework to calculate the number of infectious and upcoming infectious individuals out of 100 000 000 potential travellers from each country, and assessed six importation risk reduction strategies; Strategy 1 (S1) has no screening on entry, S2 tests all travellers and isolates test positives where those who test negative at 7 days are permitted entry, S3 the equivalent but for a 14 day period, S4 quarantines all travellers for 7 days where all are subsequently permitted entry, S5 the equivalent for 14 days and S6 the testing of all travellers and prevention of entry for those who test positive. RESULTS: The average reduction in case importation across countries relative to S1 is 90.2% for S2, 91.7% for S3, 55.4% for S4, 91.2% for S5 and 77.2% for S6. An average of 79.6% of infected travellers are infectious upon arrival. For the top 100 exporting countries, an 88.2% average reduction in secondary cases is expected through S2 with the 7-day isolation of test positives, increasing to 92.1% for S3 for 14-day isolation. A substantially smaller reduction of 30.0% is expected for 7-day all traveller quarantining, increasing to 84.3% for 14-day all traveller quarantining. CONCLUSIONS: The testing and isolation of test positives should be implemented provided good testing practices are in place. If testing is not feasible, quarantining for a minimum of 14 days is recommended with strict adherence measures in place.

5.
BMC Infect Dis ; 20(1): 598, 2020 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-32791999

RESUMO

BACKGROUND: The emergence of a novel coronavirus (SARS-CoV-2) in Wuhan, China, at the end of 2019 has caused widespread transmission around the world. As new epicentres in Europe and America have arisen, of particular concern is the increased number of imported coronavirus disease 2019 (COVID-19) cases in Africa, where the impact of the pandemic could be more severe. We aim to estimate the number of COVID-19 cases imported from 12 major epicentres in Europe and America to each African country, as well as the probability of reaching 10,000 cases in total by the end of March, April, May, and June following viral introduction. METHODS: We used the reported number of cases imported from the 12 major epicentres in Europe and America to Singapore, as well as flight data, to estimate the number of imported cases in each African country. Under the assumption that Singapore has detected all the imported cases, the estimates for Africa were thus conservative. We then propagated the uncertainty in the imported case count estimates to simulate the onward spread of the virus, until 10,000 cases are reached or the end of June, whichever is earlier. Specifically, 1,000 simulations were run separately under four different combinations of parameter values to test the sensitivity of our results. RESULTS: We estimated Morocco, Algeria, South Africa, Egypt, Tunisia, and Nigeria as having the largest number of COVID-19 cases imported from the 12 major epicentres. Based on our 1,000 simulation runs, Morocco and Algeria's estimated probability of reaching 10,000 cases by end of March was close to 100% under all scenarios. In particular, we identified countries with less than 1,000 cases in total reported by end of June whilst the estimated probability of reaching 10,000 cases by then was higher than 50% even under the most optimistic scenario. CONCLUSIONS: Our study highlights particular countries that are likely to reach (or have reached) 10,000 cases far earlier than the reported data suggest, calling for the prioritization of resources to mitigate the further spread of the epidemic.


Assuntos
Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/transmissão , Pneumonia Viral/epidemiologia , Pneumonia Viral/transmissão , África/epidemiologia , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/virologia , Humanos , Modelos Estatísticos , Pandemias , Pneumonia Viral/virologia , Probabilidade
6.
Adv Mater ; 32(25): e1907227, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32402131

RESUMO

Polymer-based dielectric materials play a key role in advanced electronic devices and electric power systems. Although extensive research has been devoted to improve their energy-storage performances, it is a great challenge to increase the breakdown strength of polymer nanocomposites in terms of achieving high energy density and good reliability under high voltages. Here, a general strategy is proposed to significantly improve their breakdown strength and energy storage by adding negatively charged Ca2 Nb3 O10 nanosheets. A dramatically enhanced breakdown strength (792 MV m-1 ) and the highest energy density (36.2 J cm-3 ) among all flexible polymer-based dielectrics are observed in poly(vinylidene fluoride)-based nanocomposite capacitors. The strategy generalizability is verified by the similar substantial enhancements of breakdown strength and energy density in polystyrene-based nanocomposites. Phase-field simulations demonstrate that the further enhanced breakdown strength is ascribed to the local electric field, produced by the negatively charged Ca2 Nb3 O10 nanosheets sandwiched with the positively charged polyethyleneimine, which suppresses the secondary impact-ionized electrons and blocks the breakdown path in nanocomposites. The results demonstrate a new horizon of high-energy-density flexible capacitors.

7.
Rev Sci Instrum ; 91(2): 026105, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32113384

RESUMO

We report on a novel dielectric barrier discharge (DBD) instrument with asymmetrical electrodes. It consists of three water electrodes, one big electrode faces to two small electrodes placed side by side, any one of two small electrodes connects with a high-voltage diode which can control on or off of applied power. Using this DBD experimental setup, the phenomenon of forming two kinds of different patterns at the different parts of discharge gap simultaneously is investigated for the first time. The spatio-temporal characteristic of these different patterns limited by the boundary which contains two connected same circles is studied. It is shown that although the power source is applied on one part of the discharge gap at a half period because of existence of high voltage photodiode, the discharge occurs at both areas in each half period of the applied voltage. Results have prospective applications for studying the discharge mechanism and different characteristic of positive and negative charges in forming of pattern.

8.
Nat Commun ; 11(1): 1439, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32188861

RESUMO

Next-generation non-volatile memories with ultrafast speed, low power consumption, and high density are highly desired in the era of big data. Here, we report a high performance memristor based on a Ag/BaTiO3/Nb:SrTiO3 ferroelectric tunnel junction (FTJ) with the fastest operation speed (600 ps) and the highest number of states (32 states or 5 bits) per cell among the reported FTJs. The sub-nanosecond resistive switching maintains up to 358 K, and the write current density is as low as 4 × 103 A cm-2. The functionality of spike-timing-dependent plasticity served as a solid synaptic device is also obtained with ultrafast operation. Furthermore, it is demonstrated that a Nb:SrTiO3 electrode with a higher carrier concentration and a metal electrode with lower work function tend to improve the operation speed. These results may throw light on the way for overcoming the storage performance gap between different levels of the memory hierarchy and developing ultrafast neuromorphic computing systems.

9.
Lancet Infect Dis ; 20(6): 678-688, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32213332

RESUMO

BACKGROUND: Since the coronavirus disease 2019 outbreak began in the Chinese city of Wuhan on Dec 31, 2019, 68 imported cases and 175 locally acquired infections have been reported in Singapore. We aimed to investigate options for early intervention in Singapore should local containment (eg, preventing disease spread through contact tracing efforts) be unsuccessful. METHODS: We adapted an influenza epidemic simulation model to estimate the likelihood of human-to-human transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a simulated Singaporean population. Using this model, we estimated the cumulative number of SARS-CoV-2 infections at 80 days, after detection of 100 cases of community transmission, under three infectivity scenarios (basic reproduction number [R0] of 1·5, 2·0, or 2·5) and assuming 7·5% of infections are asymptomatic. We first ran the model assuming no intervention was in place (baseline scenario), and then assessed the effect of four intervention scenarios compared with a baseline scenario on the size and progression of the outbreak for each R0 value. These scenarios included isolation measures for infected individuals and quarantining of family members (hereafter referred to as quarantine); quarantine plus school closure; quarantine plus workplace distancing; and quarantine, school closure, and workplace distancing (hereafter referred to as the combined intervention). We also did sensitivity analyses by altering the asymptomatic fraction of infections (22·7%, 30·0%, 40·0%, and 50·0%) to compare outbreak sizes under the same control measures. FINDINGS: For the baseline scenario, when R0 was 1·5, the median cumulative number of infections at day 80 was 279 000 (IQR 245 000-320 000), corresponding to 7·4% (IQR 6·5-8·5) of the resident population of Singapore. The median number of infections increased with higher infectivity: 727 000 cases (670 000-776 000) when R0 was 2·0, corresponding to 19·3% (17·8-20·6) of the Singaporean population, and 1 207 000 cases (1 164 000-1 249 000) when R0 was 2·5, corresponding to 32% (30·9-33·1) of the Singaporean population. Compared with the baseline scenario, the combined intervention was the most effective, reducing the estimated median number of infections by 99·3% (IQR 92·6-99·9) when R0 was 1·5, by 93·0% (81·5-99·7) when R0 was 2·0, and by 78·2% (59·0 -94·4) when R0 was 2·5. Assuming increasing asymptomatic fractions up to 50·0%, up to 277 000 infections were estimated to occur at day 80 with the combined intervention relative to 1800 for the baseline at R0 of 1·5. INTERPRETATION: Implementing the combined intervention of quarantining infected individuals and their family members, workplace distancing, and school closure once community transmission has been detected could substantially reduce the number of SARS-CoV-2 infections. We therefore recommend immediate deployment of this strategy if local secondary transmission is confirmed within Singapore. However, quarantine and workplace distancing should be prioritised over school closure because at this early stage, symptomatic children have higher withdrawal rates from school than do symptomatic adults from work. At higher asymptomatic proportions, intervention effectiveness might be substantially reduced requiring the need for effective case management and treatments, and preventive measures such as vaccines. FUNDING: Singapore Ministry of Health, Singapore Population Health Improvement Centre.


Assuntos
Controle de Doenças Transmissíveis/métodos , Infecções por Coronavirus/prevenção & controle , Modelos Estatísticos , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Número Básico de Reprodução , Betacoronavirus , Simulação por Computador , Infecções por Coronavirus/transmissão , Humanos , Influenza Humana/prevenção & controle , Pneumonia Viral/transmissão , Quarentena , Instituições Acadêmicas , Singapura/epidemiologia , Local de Trabalho
11.
Am J Epidemiol ; 188(8): 1529-1538, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31062837

RESUMO

National data on dengue notifications do not capture all dengue infections and do not reflect the true intensity of disease transmission. To assess the true dengue infection rate and disease control efforts in Singapore, we conducted age-stratified serosurveys among residents after a 2013 outbreak that was the largest dengue outbreak on record. The age-weighted prevalence of dengue immunoglobulin G among residents was 49.8% (95% confidence interval: 48.4, 51.1) in 2013 and 48.6% (95% confidence interval: 47.0, 50.0) in 2017; prevalence increased with age. Combining these data with those from previous serosurveys, the year-on-year estimates of the dengue force of infection from 1930 to 2017 revealed a significant decrease from the late 1960s to the mid-1990s, after which the force of infection remained stable at approximately 10 per 1,000 persons per year. The reproduction number (R0) had also declined since the 1960s. The reduction in dengue transmission may be attributed to the sustained national vector program and partly to a change in the age structure of the population. The improved estimated ratio of notified cases to true infections, from 1:14 in 2005-2009 to 1:6 in 2014-2017, signifies that the national notification system, which relies on diagnosed cases, has improved over time. The data also suggest that the magnitudes of dengue epidemics cannot be fairly compared across calendar years and that the current disease control program remains applicable.


Assuntos
Controle de Doenças Transmissíveis/organização & administração , Dengue/epidemiologia , Dengue/prevenção & controle , Adolescente , Adulto , Idoso , Teorema de Bayes , Feminino , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Estudos Soroepidemiológicos , Singapura/epidemiologia
12.
J Poult Sci ; 56(2): 140-147, 2019 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-32055208

RESUMO

This study aimed to evaluate the effect of dietary supplementation of a mixed yeast culture (MYC; Saccharomyces cerevisiae YJM1592 and Kluyveromyces maxianus TB7258 in a 1:1 ratio) on growth performance, nutrient digestibility, meat quality, blood parameters, and gut health of broiler chickens. In total, 576 one-day-old male broilers (Ross 308) with an average initial bodyweight (BW) of 37±0.51 g were used in a 35-day experiment with a completely randomized design. The broilers were randomly assigned to 3 dietary treatments: CON, basal diet; TRT1, CON + 0.1% MYC; and TRT 2, CON + 0.2% MYC. From days 8 to 21, the feed conversion rate (FCR) was significantly decreased in broilers fed MYC-supplemented diets. From days 22 to 35, BW gain (BWG) significantly increased with increasing MYC concentration. Throughout the experiment, BWG increased (linear effect, P=0.002) and FCR decreased with increasing MYC in the diet. MYC supplementation increased the digestibility of dry matter (DM) in broilers in a dose-dependent manner. Relative organ weight of the bursa of Fabricius linearly increased in broilers fed MYC-supplemented diets. The white blood cell count showed linear and quadratic increases in broilers fed increasing concentrations of MYC. The population of Lactobacillus in the excreta linearly increased P=0.033, whereas that of Escherichia coli tended to linearly decrease (P=0.064) in the MYC groups. This study provides a basis for future research on MYC as a growth promoter in broilers.

13.
BMJ Glob Health ; 3(4): e000801, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30233829

RESUMO

Background: Responsible for considerable global human morbidity and mortality, Aedes aegypti and Ae. albopictus are the primary vectors of several important human diseases, including dengue and yellow fever. Although numerous variables that affect mosquito survival and reproduction have been recorded at the local and regional scales, many remain untested at the global level, potentially confounding mapping efforts to date. Methods: We develop a modelling ensemble of boosted regression trees and maximum entropy models using sets of variables previously untested at the global level to examine their performance in predicting the global distribution of these two vectors. The results show that accessibility, absolute humidity and annual minimum temperature are consistently the strongest predictors of mosquito presence. Both vectors are similar in their response to accessibility and humidity, but exhibit individual profiles for temperature. Their mapped ranges are therefore similar except at peripheral latitudes, where the range of Ae. albopictus extends further, a finding consistent with ongoing trapping studies. We show that variables previously identified as being relevant, including maximum and mean temperatures, enhanced vegetation index, relative humidity and population density, are comparatively weak performers. Results: The variables identified represent three key biological mechanisms. Cold tolerance is a critical biological parameter, controlling both species' distribution northwards, and to a lesser degree for Ae. albopictus which has consequent greater inland suitability in North America, Europe and East Asia. Absolute humidity restricts the distribution of both vectors from drier areas, where moisture availability is very low, and increases their suitability in coastal areas. The latter is exacerbated by accessibility with increased likelihood of vector importation due to greater potential for human and trade movement. Conclusion: Accessibility, absolute humidity and annual minimum temperatures were the strongest and most robust global predictors of Ae. aegypti and Ae. albopictus presence, which should be considered in control efforts and future distribution projections.

14.
Soft Matter ; 14(11): 2059-2067, 2018 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-29480304

RESUMO

In the wide application of aqueous foam, creating abundant foam and processing appropriate foaming control are both essential, depending upon the actual situation; the latter process is not only harder to achieve, but also more complicated to comprehensively understand on the molecular level. In this paper, a type of natural flavor oil, carvone, was solubilized in a micelle solution of sodium dodecyl sulfate (SDS) to study the effect on the foaming properties. The foamability and foam stability of the swollen micelle solutions were experimentally characterized, and the molecular behavior of the surfactant and oil molecules before, during and after the foaming process were investigated. It was found that the solubilized carvone co-adsorbed with SDS at the gas/water interface and caused a prominent effect on the foam film stability in several approaches, thereby making the flavor oil a possible foam controller that would not inhibit foam formation, but could eliminate foam efficiently once foam was undesired. Interestingly, it was found that the release of flavor in the foaming process was promoted. Detailed discussion of the interfacial behavior of carvone and the effect on the foaming properties of surfactants in different stages of foam may provide a theoretical foundation for exploring green and smart approaches in achieving foaming control.

15.
Polymers (Basel) ; 10(3)2018 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30966303

RESUMO

Vinyl Benzoate/Heptadecafluorodecyl acrylate (VBe/HFDA) co-polymers were synthesized and characterized as thickening agents for supercritical carbon dioxide (SC-CO2). The solubility and thickening capability of the co-polymer samples in SC-CO2 were evaluated by measuring cloud point pressure and relative viscosity. The molecular dynamics (MD) simulation for all atoms was employed to simulate the microscopic molecular behavior and the intermolecular interaction of co-polymer⁻CO2 systems. We found that the introduction of VBe group decreased the polymer⁻CO2 interaction and increased the polymer⁻polymer interaction, leading to a reduction in solubility of the co-polymers in SC-CO2. However, the co-polymer could generate more effective inter-chain interaction and generate more viscosity enhancement compared to the Poly(Heptadecafluorodecyl) (PHFDA) homopolymer due to the driving force provided by π-π stacking of the VBe groups. The optimum molar ratio value for VBe in co-polymers for the viscosity enhancement of SC-CO2 was found to be 0.33 in this work. The P(HFDA0.67-co-VBe0.33) was able to enhance the viscosity of SC-CO2 by 438 times at 5 wt. %. Less VBe content would result in a lack of intermolecular interaction, although excessive VBe content would generate more intramolecular π-π stacking and less intermolecular π-π stacking. Both conditions reduce the thickening capability of the P(HFDA-co-VBe) co-polymer. This work presented the relationship between structure and performance of the co-polymers in SC-CO2 by combining experiment and molecular simulations.

16.
ACS Omega ; 2(11): 7600-7608, 2017 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31457320

RESUMO

Molecular dynamics simulation studies were employed to investigate the microscopic behaviors of CH4 and CO2 molecules in slit-nanopores (SNPs) with various surfaces and different compositions. Three kinds of SNPs were constructed by a pair-wise combination of graphene, silica, and the calcite surface. The grand canonical Monte Carlo and molecular dynamics simulation methods were used to investigate the adsorption and self-diffusion of the gases in the nanopores. It is found that in all three cases, the CH4 molecules prefer to adsorb onto the graphene surface, whereas the CO2 molecules prefer to adsorb onto the calcite surface. The adsorption intensity of gases adsorbed onto various surfaces, the adsorption distances, along with the details of adsorption orientations of CH4 and CO2 molecules on various surfaces are calculated. The surface characteristics, such as surface roughness and charge distribution, are analyzed to help understand the microscopic adsorption behaviors of the gases on the specific surface. It was found that competitive adsorptions of CO2 over CH4 broadly occurred, especially in the SNPs containing calcite, because of the strong adsorption interactions between the CO2 molecules and the calcite surface. This work provides the microbehaviors of CH4 and CO2 in SNPs with various surfaces in different compositions to provide useful guidance for better understanding about the microstate of gases in complex nanoporous shale formation and to give out useful guidance for enhancing shale gas recovery by injecting CO2.

17.
Lancet Planet Health ; 1(5): e180-e187, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29851639

RESUMO

BACKGROUND: Potential synergies between public health and environmental protection that offer new opportunities for achieving health and sustainable development targets have been postulated. However, empirical evidence of the effect of ecosystem degradation and protection on public health outcomes is scarce, which restricts policy makers' ability to assess the net health effects of land-use change. METHODS: We used generalised linear mixed-effects models to analyse data for 35 547 households in 1766 communities from the Cambodian Demographic Health Surveys to investigate the relation between health and protected areas across deforestation gradients in Cambodia between Feb 1, 2005, and April 30, 2014. Diarrhoea, acute respiratory infection, and fever in children younger than 5 years were used as population health indicators. Dense and mixed forest coverage were derived from Open Development Cambodia, and forest loss was calculated from 2000 to 2004, 2004 to 2009, and 2009 to 2014. The incidence of non-specific illness and injury in people older than 15 years was used as a negative control. Our analyses included rich pseudo-panel data (combining cross-sectional datasets from 2005, 2010, and 2014) that accounted for socioeconomic, demographic, and behavioural characteristics, and had a negative control, approximating a quasi-experimental study design. FINDINGS: Deforestation of dense forest was associated with an increased incidence of diarrhoea (p=0·007), fever (p=0·0495), and acute respiratory infection in children (p=0·003). For example, a 10 percentage point increase in loss of dense forest was estimated to be associated with an increase of 14·1% (95% CI 2·6-35·8) in the incidence of diarrhoea in children younger than 5 years per household in the 2 weeks before the Cambodian Demographic Health Surveys. Protected area coverage, but not type, was associated with decreased incidences of diarrhoea (p=0·028) and acute respiratory infection (p=0·030). Apart from an association between mixed forest coverage and increased incidence of diarrhoea, forest coverage was not associated with any health outcomes. INTERPRETATION: Deforestation is associated with increased risk of several major sources of global childhood morbidity and mortality. Although causal mechanisms are unclear, our findings suggest that protected areas could help to alleviate the global health burden, presenting new possibilities for simultaneous achievement of public health and conservation goals. FUNDING: Ministry of Education of Singapore.

18.
Langmuir ; 32(30): 7503-11, 2016 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-27434752

RESUMO

In this paper, the detailed behaviors of all the molecules, especially the interfacial array behaviors of surfactants and diffusion behaviors of gas molecules, in foam systems with different gases (N2, O2, and CO2) being used as foaming agents were investigated by combining molecular dynamics simulation and experimental approaches for the purpose of interpreting how the molecular behaviors effect the properties of the foam and find out the key factors which fundamentally determine the foam stability. Sodium dodecyl sulfate SDS was used as the foam stabilizer. The foam decay and the drainage process were determined by Foamscan. A texture analyzer (TA) was utilized to measure the stiffness and viscoelasticity of the foam films. The experimental results agreed very well with the simulation results by which how the different gas components affect the interfacial behaviors of surfactant molecules and thereby bring influence on foam properties was described.

19.
Int J Mol Med ; 38(2): 594-600, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27314666

RESUMO

As integrins are mechanoresponsive, there exists an intimate relationship between integrins and mechanical strain. Integrin-ß1 mediates the impact of mechanical strain on bone. Mechanical strain induces bone formation through the activation of ß-catenin pathways, which suggests that integrin-ß1 mediates ß-catenin signaling in osteoblasts in response to mechanical strain. In the present study, we examined the role of integrin-ß1 in Wnt/ß-catenin signal transduction in mechanically strained osteoblasts. MC3T3-E1 osteoblastic cells were transfected with integrin-ß1 small interfering RNA (si-Itgß1), and exposed to mechanical tensile strain of 2,500 microstrain (µÎµ) using a four-point bending device. The mechanical strain enhanced the mRNA expression of integrin-ß1, the protein levels of phosphorylated (p-) glycogen synthase kinase-3ß (GSK­3ß) and ß-catenin, simultaneously increased the mRNA levels of runt-related transcriptional factor 2 (Runx2) and osteocalcin (OCN), the protein levels of bone morphogenetic protein (BMP)-2 and -4 and enhanced the alkaline phosphatase (ALP) activity of the ME3T3-E1 cells. The elevations were inhibited by si-Itgß1. Additionally, the mechanical strain induced the nuclear translocation of ß-catenin into the nucleus, which was also inhibited by si-Itgß1. These findings indicated that mechanical strain promoted osteoblastic differentiation through integrin­ß1­mediated ß-catenin signaling.


Assuntos
Diferenciação Celular , Integrina beta1/metabolismo , Osteoblastos/citologia , Osteoblastos/metabolismo , Transdução de Sinais , Estresse Mecânico , beta Catenina/metabolismo , Fosfatase Alcalina/metabolismo , Animais , Linhagem Celular , Núcleo Celular/metabolismo , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Técnicas de Silenciamento de Genes , Glicogênio Sintase Quinase 3 beta/metabolismo , Camundongos , Fosforilação , Transporte Proteico , Interferência de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo
20.
Colloids Surf B Biointerfaces ; 141: 206-212, 2016 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-26852104

RESUMO

The foam properties, such as the foamability, foam stability, drainage, coalescence and bulk rheology, of aqueous solutions containing an eco-friendly exopolysaccharide (EPS) secreted by a deep-sea mesophilic bacterium, Wangia profunda SM-A87, and an anionic surfactant, sodium fatty alcohol polyoxyethylene ether sulfate (AES), were studied. Both the foamability and foam stability of the EPS/AES solutions are considerably higher than those of single AES solutions, even at very low AES concentrations, although pure EPS solutions cannot foam. The improved foamability and foam stability arise from the formation of the EPS/AES complex via hydrogen bonds at the interfaces. The synergism between the EPS and AES decreases the surface tension, increases the interfacial elasticity and water-carrying capacity, and suppresses the coalescence and collapse of the foams. The EPS/AES foams are more salt-resistant than the AES foams. This work provides not only a new eco-friendly foam with great potential for use in enhanced oil recovery and health-care products but also useful guidance for designing other environmentally friendly foam systems that exhibit high performance.


Assuntos
Éteres/química , Álcoois Graxos/química , Polietilenoglicóis/química , Polissacarídeos Bacterianos/química , Tensoativos/química , Ligação de Hidrogênio , Modelos Moleculares , Estrutura Molecular , Reologia , Soluções/química , Tensão Superficial , Viscosidade , Água/química
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