A double rare earth doped CD nanoplatform for nanocatalytic/starving-like synergistic therapy with GSH-depletion and enhanced reactive oxygen species generation.

Cancer has been one of the principal diseases threatening human health in the world. Traditional chemotherapy, radiotherapy and surgery in clinical applications have some disadvantages, such as inefficiency, low specificity, and serious side effects. Therefore, some emerging synergistic therapies have been developed for more accurate diagnosis and more efficient treatment of cancer. Herein, novel Ce-Gd@CDs-GOx nanozymes were obtained by combining magnetic resonance/fluorescence (MR/FL) imaging and nanocatalytic/starving-like synergistic therapy for tumor tissue imaging and efficient cancer treatment. The as-prepared Ce-Gd@CDs-GOx nanozymes with a diameter of 25.0 ± 0.8 nm exhibited favorable physiological stability, negligible toxicity, bright fluorescence and strong T1-weighted MR imaging (MRI) performance (10.97 mM-1 s-1). Moreover, the nanozymes could not only cut off the nutrient supply of tumor cells, but also generate ROS to synergistically enhance antitumor efficacy. The coexistence of Ce3+/Ce4+ in Ce-Gd@CDs-GOx endowed them with attractive capacity for alleviating hypoxia and enhancing GSH consumption to induce the apoptosis of tumor cells. Furthermore, most of the 4T1 cells treated with Ce-Gd@CDs-GOx nanozymes were damaged in the CCK-8 and Calcein-AM/PI staining assays, indicating the excellent efficiency of intracellular synergistic therapy. In summary, this study offered a promising strategy to design a nanoplatform for MR/FL imaging-guided nanocatalytic and starvation-like synergistic therapy of cancer.

Gadolinium (III) doped carbon dots as dual-mode sensor for the recognition of dopamine hydrochloride and glutamate enantiomers with logic gate operation.

Dopamine hydrochloride (DH) and D-Glutamic acid (D-Glu) are important excitatory neurotransmitters, which are closely relative to central nervous system diseases. Therefore, it is critical to develop the sensitive and facile sensor to precisely monitor the changes of these neurotransmitters. Herein, the gadolinium-doped carbon dots (Gd-CDs) were synthesized by a low-cost and effortless one-pot solvothermal method. These CDs exhibited rapid and reliable fluorescent and colorimetric response signals towards DH and D-Glu. Interestingly, the fluorescence of Gd-CDs could be selectively quenched by DH owing to the fact that the Gd-CDs could coordinate with phenolic hydroxyl groups of DH. Moreover, the quench process was effectively inhibited because the D-Glu competitively coordinated with Gd-CDs-DH system to form a more stable complex. In fluorescence mode, the designed fluorescence sensor possessed an excellent linear relationship for DH in the range from 1 to 10 µM with a low detection limit of 1.26 nM, and the fluorescence could be selectively recovered by D-Glu. In colorimetric manner, DH and D-Glu could be detected by UV-Vis absorption spectrum in the range of 1-15 µM and 1-1.50 mM, respectively. Moreover, the proposed method could not only easily monitor the DH and D-Glu in aqueous solutions as well as mouse serum and human urine samples, but also be employed for detecting DH and D-Glu in cells. Fortunately, the fluorescent and colorimetric dual readout AND logic operation was successfully demonstrated in all-aqueous media. Accordingly, the prepared Gd-CDs hold the potential to become a promising nano-sensor for DH and D-Glu sensing in disease diagnosis areas.

Epidemiological Characteristics and Transmissibility for SARS-CoV-2 of Population Level and Cluster Level in a Chinese City.

Background: To date, there is a lack of sufficient evidence on the type of clusters in which severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is most likely to spread. Notably, the differences between cluster-level and population-level outbreaks in epidemiological characteristics and transmissibility remain unclear. Identifying the characteristics of these two levels, including epidemiology and transmission dynamics, allows us to develop better surveillance and control strategies following the current removal of suppression measures in China. Methods: We described the epidemiological characteristics of SARS-CoV-2 and calculated its transmissibility by taking a Chinese city as an example. We used descriptive analysis to characterize epidemiological features for coronavirus disease 2019 (COVID-19) incidence database from 1 Jan 2020 to 2 March 2020 in Chaoyang District, Beijing City, China. The susceptible-exposed-infected-asymptomatic-recovered (SEIAR) model was fitted with the dataset, and the effective reproduction number (Reff ) was calculated as the transmissibility of a single population. Also, the basic reproduction number (R0) was calculated by definition for three clusters, such as household, factory and community, as the transmissibility of subgroups. Results: The epidemic curve in Chaoyang District was divided into three stages. We included nine clusters (subgroups), which comprised of seven household-level and one factory-level and one community-level cluster, with sizes ranging from 2 to 17 cases. For the nine clusters, the median incubation period was 17.0 days [Interquartile range (IQR): 8.4-24.0 days (d)], and the average interval between date of onset (report date) and diagnosis date was 1.9 d (IQR: 1.7 to 6.4 d). At the population level, the transmissibility of the virus was high in the early stage of the epidemic (Reff = 4.81). The transmissibility was higher in factory-level clusters (R0 = 16) than in community-level clusters (R0 = 3), and household-level clusters (R0 = 1). Conclusions: In Chaoyang District, the epidemiological features of SARS-CoV-2 showed multi-stage pattern. Many clusters were reported to occur indoors, mostly from households and factories, and few from the community. The risk of transmission varies by setting, with indoor settings being more severe than outdoor settings. Reported household clusters were the predominant type, but the population size of the different types of clusters limited transmission. The transmissibility of SARS-CoV-2 was different between a single population and its subgroups, with cluster-level transmissibility higher than population-level transmissibility.

[The impact of antibiotic treatment in patients with influenza-like illness].

OBJECTIVE: To study the etiology of influenza-like illness (ILI) in Beijing, and to investigate the impact of antibiotic treatment on outcomes. METHODS: This was a prospective cohort study. Patients with diagnosis of influenza-like illness were prospectively enrolled for study of bacterial and viral pathogens. Demographic characteristics, underlying diseases, respiratory and extrapulmonary symptoms, laboratory tests were also collected for analysis of relationship between drug therapy and outcomes. RESULTS: A total of 476 cases were enrolled between Dec. 2006 and Apr. 2007, of whom 454 cases were used for analysis. Influenza virus was the most common pathogen( n = 197, 43.4%), with other pathogens rarely seen. The mean age of the patients was (33 +/- 13) years, and the ratio of male to female was 1.1:1. Twenty four patients (5.3% ) received influenza vaccine. The rate of antibiotic prescription after onset of illness was 63.4%, but none received antiviral drugs such as Oseltamivir and amantadine. Compared with influenza-negative patients, patients with influenza were older, had more underlying diseases and had greater severity of symptoms such as cough, sore throat, headache and myalgia (but with no statistical differences). The influenza syndrome (T > or = 39 degrees C plus cough, sore throat and headache or myalgia) was more common in the influenza group compared to the influenza-negative patients (P < 0.05). The ratio of antibiotic prescription was 67% in the influenza group, and the total white blood cell and platelet count, percentage of neutrophils were higher in antibiotic treatment patients compared with non-antibiotic treatment patients (P < 0.01). The cost in patients who received antibiotics was twice as much as non-antibiotic treatment patients (P < 0.05), but the defervescence time and respiratory symptom alleviation time did not differ. Cox regression analysis showed that the total white blood count and the differentials (OR value 1.049 and 1.014, respectively), but not antibiotic use were the independent risk factors for longer defervescence time. CONCLUSION: Influenza virus was the most common pathogen for adult patients with ILI in Beijing city during the winter and the spring seasons. Antibiotic treatment of adult patients with ILI did not improve illness resolution, while the cost was increased significantly.