Background: Since December 2019, acute respiratory disease (ARD) due to 2019 novel coronavirus (2019-nCoV) emerged in Wuhan city and rapidly spread throughout China. We sought to delineate the clinical characteristics of these cases. Methods:We extracted the data on 1,099 patients with laboratory-confirmed 2019-nCoV ARD from 552 hospitals in 31 provinces/provincial municipalities through January 29 th , 2020. Results:The median age was 47.0 years, and 41.90% were females. Only 1.18% of patients had a direct contact with wildlife, whereas 31.30% had been to Wuhan and 71.80% had contacted with people from Wuhan. Fever (87.9%) and cough (67.7%) were the most common symptoms. Diarrhea is uncommon. The median incubation period was 3.0 days (range, 0 to 24.0 days). On admission, ground-glass opacity was the typical radiological finding on chest computed tomography (50.00%).Significantly more severe cases were diagnosed by symptoms plus reverse-transcriptase polymerase-chain-reaction without abnormal radiological findings than non-severe cases (23.87% vs. 5.20%, P<0.001). Lymphopenia was observed in 82.1% of patients. 55 patients (5.00%) were . CC-BY-NC-ND 4.0 International license It is made available under a author/funder, who has granted medRxiv a license to display the preprint in perpetuity.is the (which was not peer-reviewed) The copyright holder for this preprint . https://doi.org/10. 1101 /2020 admitted to intensive care unit and 15 (1.36%) succumbed. Severe pneumonia was independently associated with either the admission to intensive care unit, mechanical ventilation, or death in multivariate competing-risk model (sub-distribution hazards ratio, 9.80; 95% confidence interval, 4.06 to 23.67). Conclusions:The 2019-nCoV epidemic spreads rapidly by human-to-human transmission. Normal radiologic findings are present among some patients with 2019-nCoV infection. The disease severity (including oxygen saturation, respiratory rate, blood leukocyte/lymphocyte count and chest X-ray/CT manifestations) predict poor clinical outcomes. Abstract: 249 words; main text: 2677 words : medRxiv preprint Clinical outcomesThe percentages of patients being admitted to the ICU, requiring invasive ventilation and death were 5.00%, 2.18% and 1.36%, respectively. This corresponded to 67 (6.10%) of patients having reached to the composite endpoint ( Table 3).Results of the univariate competing risk model are shown in Table E1 in Supplementary Appendix. Severe pneumonia cases (SDHR, 9.803; 95%CI, 4.06 to 23.67), leukocyte count greater than 4,000/mm 3 (SDHR, 4.01; 95%CI, 1.53 to 10.55) and interstitial abnormality on chest X-ray (SDHR, 4.31; 95%CI, 1.73 to 10.75) were associated with the composite endpoint (Fig. 2, see Table E2 in Supplementary Appendix). Sensitivity analyses are shown in Figure E2 in Supplementary Appendix. DiscussionThis study has shown that fever occurred in only 43.8% of patients with 2019-nCoV ARD on presentation but developed in 87.9% following hospitalization. Severe pneumonia occurred in 15.7% of cases. No radiolo...

High particle uniformity, high photoluminescence quantum yields, narrow and symmetric emission spectral lineshapes and minimal single dot emission intermittency (known as blinking) have been recognized as universal requirements for the successful use of colloidal quantum dots (QDs) in nearly all optical applications. However, synthesizing samples that simultaneously meet all these four criteria has proven challenging. Here, we report the synthesis of such high-quality CdSe/CdS core/shell QDs in an optimized process which maintains a slow growth rate of the shell through the use of octanethiol and cadmium oleate as precursors. In contrast with previous observations, single-QD blinking is significantly suppressed with only a relatively thin shell. In addition, we demonstrate the elimination of the ensemble luminescence photodarkening that is an intrinsic consequence of QD blinking statistical aging. Furthermore, the small size and high photoluminescence quantum yields of these novel QDs render them superior in vivo imaging agents compared to conventional QDs. We anticipate that this new generation of QDs will also result in significant improvement in the performance of QDs in other applications such as solid-state lighting and illumination.

The blood vessels of cancerous tumours are leaky1–3 and poorly organized4–7. This can increase the interstitial fluid pressure (IFP) inside tumours and reduce blood supply to them, which impairs drug delivery8–9. Anti-angiogenic therapies – which “normalize” the abnormal blood vessels in tumours by making them less leaky – have been shown to improve the delivery and effectiveness of chemotherapeutics with low molecular-weights10, but it remains unclear whether normalizing tumour vessels can improve the delivery of nanomedicines. Here we show that repairing the abnormal vessels in mammary tumours, by blocking vascular endothelial growth factor (VEGF) receptor-2, improves the delivery of small nanoparticles (12nm diameter) while hindering the delivery of large nanoparticles (125nm diameter). We utilize a mathematical model to show that reducing vessel wall pore sizes through normalization decreases IFP in tumours, allowing small nanoparticles to enter them more rapidly. However, increased steric and hydrodynamic hindrances, also associated with smaller pores, make it more difficult for large nanoparticles to enter tumours. Our results further suggest that smaller (~12nm) nanomedicines are ideal for cancer therapy, owing to superior tumour penetration.

Colloidal superparticles are nanoparticle assemblies in the form of colloidal particles. The assembly of nanoscopic objects into mesoscopic or macroscopic complex architectures allows bottom-up fabrication of functional materials. We report that the self-assembly of cadmium selenide-cadmium sulfide (CdSe-CdS) core-shell semiconductor nanorods, mediated by shape and structural anisotropy, produces mesoscopic colloidal superparticles having multiple well-defined supercrystalline domains. Moreover, functionality-based anisotropic interactions between these CdSe-CdS nanorods can be kinetically introduced during the self-assembly and, in turn, yield single-domain, needle-like superparticles with parallel alignment of constituent nanorods. Unidirectional patterning of these mesoscopic needle-like superparticles gives rise to the lateral alignment of CdSe-CdS nanorods into macroscopic, uniform, freestanding polymer films that exhibit strong photoluminescence with a striking anisotropy, enabling their use as downconversion phosphors to create polarized light-emitting diodes.

In this paper, we report a new doping approach using a three-step synthesis to make high-quality Mn-doped CdS/ZnS core/shell nanocrystals. This approach allows precise control of the Mn radial position and doping level in the core/shell nanocrystals. On the basis of this synthetic advance, we have demonstrated the first example in which optical properties of Mn-doped nanocrystals strongly depend on Mn radial positions inside the nanocrystals. In addition, we have synthesized nanocrystals with a room-temperature Mn-emission quantum yield of 56%, which is nearly twice as high as that of the best Mn-doped nanocrystals reported previously. Nanocrystals with such a high-emission quantum yield are very important to applications such as nanocrystal-based biomedical diagnosis.

For in vivo imaging, the short-wavelength infrared region (SWIR; 1000–2000 nm) provides several advantages over the visible and near-infrared regions: general lack of autofluorescence, low light absorption by blood and tissue, and reduced scattering. However, the lack of versatile and functional SWIR emitters has prevented the general adoption of SWIR imaging by the biomedical research community. Here, we introduce a class of high-quality SWIR-emissive indium-arsenide-based quantum dots (QDs) that are readily modifiable for various functional imaging applications, and that exhibit narrow and size-tunable emission and a dramatically higher emission quantum yield than previously described SWIR probes. To demonstrate the unprecedented combination of deep penetration, high spatial resolution, multicolor imaging and fast-acquisition-speed afforded by the SWIR QDs, we quantified, in mice, the metabolic turnover rates of lipoproteins in several organs simultaneously and in real time as well as heartbeat and breathing rates in awake and unrestrained animals, and generated detailed three-dimensional quantitative flow maps of the mouse brain vasculature.

Shape dependent: Fluorescent quantum‐dot‐based nanospheres and nanorods with identical hydrodynamic size and surface properties but different aspect ratios were developed for real‐time in vivo tumor imaging. The nanorods exhibited superior transport and distribution into mammary tumors in vivo versus nanospheres of similar plasma half‐life.

Background: Ethical challenges are common in clinical nursing practice, and an infectious environment could put nurses under ethical challenges more easily, which may cause nurses to submit to negative emotions and psychological pressure, damaging their mental health. Purpose: To examine the ethical challenges encountered by nurses caring for patients with the novel coronavirus pneumonia (COVID-19) and to provide nurses with suggestions and support regarding promotion of their mental health. Research design and method: A qualitative study was carried out using a qualitative content analysis. The participants were 18 nurses who agreed to attend an interview and describe their own experiences of providing care to COVID-19 patients in China. They were purposively sampled, and structured, in-depth interviews were performed. Data were iteratively collected and analyzed from February to March 2020. Ethical considerations: The proposal was approved by the Research Ethics Committee of the Second Hospital of Shandong University, China. Findings: The findings revealed three main themes and 10 categories. The themes were the following: (1) ethical challenges (people with COVID-19, inequality, professional ethics, and job competency); (2) coping styles (active control and planning, seeking support as well as catharsis, and staying focused); and (3) impacts on career (specialized nursing skills, scientific research ability, and management skills). Conclusion: Nurses faced ethical challenges on multiple fronts in caring for COVID-19 patients. The results may help nurses with more safety, ethics, and humanistic care in nursing practice.