•For the ongoing novel coronavirus disease (CODID-19) outbreak in Wuhan, China, the Chinese government has implemented control measures such as city lockdown to mitigate the impact of the ...epidemic.•We model the outbreak in Wuhan with individual reaction and governmental action (holiday extension, city lockdown, hospitalisation and quarantine) based on some parameters of the 1918 influenza pandemic in London, United Kingdom.•We show the different effects of individual reaction and governmental action and preliminarily estimate the magnitude of these effects.•We also preliminarily estimate the time-varying reporting ratio.
The ongoing coronavirus disease 2019 (COVID-19) outbreak, emerged in Wuhan, China in the end of 2019, has claimed more than 2600 lives as of 24 February 2020 and posed a huge threat to global public health. The Chinese government has implemented control measures including setting up special hospitals and travel restriction to mitigate the spread. We propose conceptual models for the COVID-19 outbreak in Wuhan with the consideration of individual behavioural reaction and governmental actions, e.g., holiday extension, travel restriction, hospitalisation and quarantine. We employe the estimates of these two key components from the 1918 influenza pandemic in London, United Kingdom, incorporated zoonotic introductions and the emigration, and then compute future trends and the reporting ratio. The model is concise in structure, and it successfully captures the course of the COVID-19 outbreak, and thus sheds light on understanding the trends of the outbreak.
Organic framework polymers have attracted much interest due to the enormous potential design space offered by the atomically precise spatial assembly of organic molecular building blocks. The ...morphology control of organic frameworks is a complex issue that hinders the development of organic frameworks for practical applications. Biomimetic self‐assembly is a promising approach for designing and fabricating multiple‐functional nanoarchitectures. A bioinspired hollow flower‐like organic framework nanosphere heterostructure comprised of carbon nitride and polydopamine (g‐C3N4@PDA) is successfully synthesized via a mild and green method. This heterostructure can effectively avoid the agglomeration of nanosheets to better access the hollow nanospheres with high open‐up specific surface area. The electron delocalization of g‐C3N4 and PDA under visible light can largely promote photoelectron transfer and enhance the photocatalytic activity of the g‐C3N4@PDA. Furthermore, the g‐C3N4@PDA can effectively enhance the generation of reactive oxygen species under irradiation, which can lead to cell apoptosis and enhance the performance for cancer therapy. Therefore, the as‐prepared g‐C3N4@PDA provides a paradigm of highly efficient photocatalyst that can be used as nanomedicine toward cancer therapy. This study could open up a new avenue for exploiting more other potential hollow nanosphere organic frameworks.
Bioinspired hollow flower‐like g‐C3N4@PDA organic framework nanospheres are successfully synthesized via a mild and green method. This strategy opens up a new avenue for exploiting more potential hollow organic framework nanospheres. Significantly, the g‐C3N4@PDA provides a paradigm of a highly efficient photo‐catalyst that can be used as nano‐medicine toward cancer therapy.
•As of March 1, 2020, Iran had reported 987 COVID-19 cases, including 54 associated deaths.•At least six neighboring countries (Bahrain, Iraq, Kuwait, Oman, Afghanistan, and Pakistan) had reported ...imported COVID-19 cases from Iran.•We estimated that 16 533 (95% confidence interval 5925–35 538) COVID-19 cases had occurred in Iran by February 25, 2020.•Iran’s ascertainment rate could have been at a level of 0.6% on February 25, 2020.
As of March 1, 2020, Iran had reported 987 novel coronavirus disease (COVID-19) cases, including 54 associated deaths. At least six neighboring countries (Bahrain, Iraq, Kuwait, Oman, Afghanistan, and Pakistan) had reported imported COVID-19 cases from Iran. In this study, air travel data and the numbers of cases from Iran imported into other Middle Eastern countries were used to estimate the number of COVID-19 cases in Iran. It was estimated that the total number of cases in Iran was 16 533 (95% confidence interval: 5925–35 538) by February 25, 2020, before the UAE and other Gulf Cooperation Council countries suspended inbound and outbound flights from Iran.
In December 2019, an outbreak of respiratory illness caused by a novel coronavirus (2019-nCoV) emerged in Wuhan, China and has swiftly spread to other parts of China and a number of foreign ...countries. The 2019-nCoV cases might have been under-reported roughly from 1 to 15 January 2020, and thus we estimated the number of unreported cases and the basic reproduction number,
, of 2019-nCoV.
We modelled the epidemic curve of 2019-nCoV cases, in mainland China from 1 December 2019 to 24 January 2020 through the exponential growth. The number of unreported cases was determined by the maximum likelihood estimation. We used the serial intervals (SI) of infection caused by two other well-known coronaviruses (CoV), Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) CoVs, as approximations of the unknown SI for 2019-nCoV to estimate
.
We confirmed that the initial growth phase followed an exponential growth pattern. The under-reporting was likely to have resulted in 469 (95% CI: 403-540) unreported cases from 1 to 15 January 2020. The reporting rate after 17 January 2020 was likely to have increased 21-fold (95% CI: 18-25) in comparison to the situation from 1 to 17 January 2020 on average. We estimated the
of 2019-nCoV at 2.56 (95% CI: 2.49-2.63).
The under-reporting was likely to have occurred during the first half of January 2020 and should be considered in future investigation.
The novel coronavirus disease 2019 (COVID-19) outbreak has caused 6088 cases and 41 deaths in Republic of Korea, and 3144 cases and 107 death in Italy by 5 March 2020, respectively. We modelled the ...transmission process in the Republic of Korea and Italy with a stochastic model, and estimated the basic reproduction number R0 as 2.6 (95% CI: 2.3–2.9) or 3.2 (95% CI: 2.9–3.5) in the Republic of Korea, under the assumption that the exponential growth starting on 31 January or 5 February 2020, and 2.6 (95% CI: 2.3–2.9) or 3.3 (95% CI: 3.0–3.6) in Italy, under the assumption that the exponential growth starting on 5 February or 10 February 2020, respectively.
In late 2022, China transitioned from a strict 'zero-COVID' policy to rapidly abandoning nearly all interventions and data reporting. This raised great concern about the presumably-rapid but ...unreported spread of the SARS-CoV-2 Omicron variant in a very large population of very low pre-existing immunity. By modeling a combination of case count and survey data, we show that Omicron spread extremely rapidly, at a rate of 0.42/day (95% credibility interval: 0.35, 0.51/day), translating to an epidemic doubling time of 1.6 days (1.6, 2.0 days) after the full exit from zero-COVID on Dec. 7, 2022. Consequently, we estimate that the vast majority of the population (97% 95%, 99%, sensitivity analysis lower limit of 90%) was infected during December, with the nation-wide epidemic peaking on Dec. 23. Overall, our results highlight the extremely high transmissibility of the variant and the importance of proper design of intervention exit strategies to avoid large infection waves.
Middle East respiratory syndrome coronavirus has been persistent in the Middle East region since 2012. Abundant scientific evidence showed that dromedary camels are the primary host of the virus. ...Majority of human cases (i.e., 75% or 88%) are due to human-to-human transmission, while the others are due to camel-to-human transmission. Mathematical modeling of Middle East respiratory syndrome coronavirus camel-to-camel transmission was lacking. Using the plug-and-play likelihood-based inference framework, we fitted a susceptible-exposed-infectious-recovered-susceptible model of camels to the reported human cases with a constant proportion of human cases from camels (i.e., either 25% or 12%). We considered two scenarios: (i) the transmission rate among camels is time-varying with a constant spill-over rate from camels to human or (ii) the spill-over rate is time-varying with a constant transmission rate among camels. Our estimated loss-of-immunity rate and prevalence of Middle East respiratory syndrome coronavirus infections among camels largely matched with previous serological or virological studies, shedding light on this issue. We recommended including dromedary camels in animal surveillance and control of Middle East respiratory syndrome coronavirus in Saudi Arabia which could help reduce their sporadic introductions to humans.
Ebola virus disease (EVD) is a rare but fatal disease of humans and other primates caused by Ebola viruses. Study shows that the 2014–2015 EVD outbreak causes more than 10,000 deaths. In this paper, ...we propose and analyze a deterministic model to study the transmission dynamics of EVD in Sierra Leone, Guinea, and Liberia. Our analyses show that the model has two equilibria: (1) the disease-free equilibrium (DFE) which is locally asymptotically stable when the basic reproduction number (
R
0
) is less than unity and unstable if it is greater than one, and (2) an endemic equilibrium (EE) which is globally asymptotically stable when
R
0
is greater than unity. Furthermore, the backward bifurcation occurs, a coexistence between a stale DFE and a stable EE even if the
R
0
is less than unity, which makes the disease control more strenuous and would depend on the initial size of subpopulation. By fitting to reported Ebola cases from Sierra Leone, Guinea, and Liberia in 2014–2015, our model has captured the epidemic patterns in all three countries and shed light on future Ebola control and prevention strategies.
The 1918 influenza pandemic was characterized by multiple epidemic waves. We investigated reactive social distancing, a form of behavioral response where individuals avoid potentially infectious ...contacts in response to available information on an ongoing epidemic or pandemic. We modelled its effects on the three influenza waves in the United Kingdom. In previous studies, human behavioral response was modelled by a Power function of the proportion of recent influenza mortality in a population, and by a Hill function, which is a function of the number of recent influenza mortality. Using a simple epidemic model with a Power function and one common set of parameters, we provided a good model fit for the observed multiple epidemic waves in London boroughs, Birmingham and Liverpool. We further applied the model parameters from these three cities to all 334 administrative units in England and Wales and including the population sizes of individual administrative units. We computed the Pearson's correlation between the observed and simulated for each administrative unit. We found a median correlation of 0.636, indicating that our model predictions are performing reasonably well. Our modelling approach is an improvement from previous studies where separate models are fitted to each city. With the reduced number of model parameters used, we achieved computational efficiency gain without over-fitting the model. We also showed the importance of reactive behavioral distancing as a potential non-pharmaceutical intervention during an influenza pandemic. Our work has both scientific and public health significance.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Oral dihydroxyphenylalanine (Dopa) administration to replenish neuronal dopamine remains the most effective treatment for Parkinson's disease (PD). However, unlike the continuous and steady dopamine ...signaling in normal neurons, oral Dopa induces dramatic fluctuations in plasma Dopa levels, leading to Dopa-induced dyskinesia. Herein, we report a functional nucleic acid-based responsive artificial enzyme (FNA-Fe
O
) for in situ continuous Dopa production. FNA-Fe
O
can cross the blood-brain barrier and target diseased neurons relying on transferrin receptor aptamer. Then, FNA-Fe
O
responds to overexpressed α-synuclein mRNA in diseased neurons for antisense oligonucleotide treatment and fluorescence imaging, while converting to tyrosine aptamer-based artificial enzyme (Apt-Fe
O
) that mimics tyrosine hydroxylase for in situ continuous Dopa production. In vivo FNA-Fe
O
treatment results in recovery of Dopa and dopamine levels and decrease of pathological overexpressed α-synuclein in PD mice model, thus ameliorating motor symptoms and memory deficits. The presented functional nucleic acid-based responsive artificial enzyme strategy provides a more neuron friendly approach for the diagnosis and treatment of PD.
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