A synthesis strategy for the preparation of ultrathin free‐standing ternary‐alloy nanosheets is reported. Ultrathin Pd‐Pt‐Ag nanosheets with a thickness of approximately 3 nm were successfully ...prepared by co‐reduction of the metal precursors in an appropriate molar ratio in the presence of CO. Both the presence of CO and the interplay between the constituent metals provide fine control over the anisotropic two‐dimensional growth of the ternary‐alloy nanostructure. The prepared Pd‐Pt‐Ag nanosheets were superior catalysts of ethanol electrooxidation owing to their specific structural and compositional characteristics. This approach will pave the way for the design of multicomponent 2D nanomaterials with unprecedented functions.
Ultrathin Pd‐Pt‐Ag nanosheets with a thickness of approximately 3 nm were successfully prepared by the co‐reduction of suitable metal precursors in an appropriate molar ratio in the presence of CO. These nanosheets are superior catalysts of ethanol electrooxidation owing to their specific structural and compositional characteristics.
Abstract
Nanomaterials with core-shell architectures are prominent examples of strain-engineered materials. The lattice mismatch between the core and shell materials can cause strong interface ...strain, which affects the surface structures. Therefore, surface functional properties such as catalytic activities can be designed by fine-tuning the misfit strain at the interface. To precisely control the core-shell effect, it is essential to understand how the surface and interface strains are related at the atomic scale. Here, we elucidate the surface-interface strain relations by determining the full 3D atomic structure of Pd@Pt core-shell nanoparticles at the single-atom level via atomic electron tomography. Full 3D displacement fields and strain profiles of core-shell nanoparticles were obtained, which revealed a direct correlation between the surface and interface strain. The strain distributions show a strong shape-dependent anisotropy, whose nature was further corroborated by molecular statics simulations. From the observed surface strains, the surface oxygen reduction reaction activities were predicted. These findings give a deep understanding of structure-property relationships in strain-engineerable core-shell systems, which can lead to direct control over the resulting catalytic properties.
Developing sensitive and stable hydrogen sensors is of great importance for sustainable energy development. Here, a novel hydrogen sensing platform is described based on colloidal clusters of Au@Pd ...core–shell nanoparticles (Au@Pd NPCs) with characteristic localized surface plasmon resonance (LSPR) properties. Au@Pd NPCs with well‐controlled topologies exhibit highly pronounced sensitivity for LSPR‐based hydrogen sensing in aqueous solution in comparison to their nanoparticle counterparts and previously reported Au–Pd bimetallic nanostructures, which can be attributed to highly promoted plasmonic field resulting from the cluster formation. Furthermore, Au@Pd NPCs show stable sensing capability for repeated hydrogen sensing cycles. The present strategy for devising high‐performance LSPR‐based hydrogen sensors via the controlled assembly of bimetallic nanoparticles can be applied to the development of efficient plasmonic platforms for various sensing applications.
Colloidal clusters of core–shell nanoparticles consisting of plasmonic Au cores and Pd shells with controlled topologies exhibit pronounced sensitivity for localized surface plasmon resonance‐based hydrogen sensing in aqueous solution due to a highly promoted plasmonic field, resulting from the cluster formation of Au@Pd bimetallic nanoparticles.
Previous studies have shown that an elevated prehospital National Early Warning Score (preNEWS) is associated with increased levels of adverse outcomes in patients with trauma. However, whether ...preNEWS is a predictor of massive transfusion (MT) in patients with trauma is currently unknown. This study investigated the accuracy of preNEWS in predicting MT and hospital mortality among trauma patients.
We analyzed adult trauma patients who were treated and transported by emergency medical services (EMS) between January 2018 and December 2019. The main exposure was the preNEWS calculated for the scene. The primary outcome was the predictive ability for MT, and the secondary outcome was 24 h mortality. We compared the prognostic performance of preNEWS with the shock index, modified shock index, and reverse shock index, and reverse shock index multiplied by Glasgow Coma Scale in the prehospital setting.
In total, 41,852 patients were included, and 1456 (3.5%) received MT. preNEWS showed the highest area under the receiver operating characteristic (AUROC) curve for predicting MT (0.8504; 95% confidence interval CI, 0.840–0.860) and 24 h mortality (AUROC 0.873; 95% CI, 0.863–0.883). The sensitivity of preNEWS for MT was 0.755, and the specificity of preNEWS for MT was 0.793. All indicies had a high negative predictive value and low positive predictive value.
preNEWS is a useful, rapid predictor for MT and 24 h mortality. Calculation of preNEWS would be helpful for making the decision at the scene such as transfer straightforward to trauma center and advanced treatment.
Incorporation of catalytically active materials into plasmonic metal nanostructures can efficiently merge the reactivity and energy-harvesting abilities of both types of materials for visible light ...photocatalysis. Herein, we explore the influence of electromagnetic hotspots in the ability of plasmonic core–shell colloidal structures to induce chemical transformations. For this study, we developed a synthetic strategy for the fabrication of Au nanoparticle (NP) trimers in aqueous solution through fine controlled galvanic replacement between Ag nanoprisms and Au precursors. Core–shell Au@M NP trimers with catalytically active metals (M = Pd, Pt) were subsequently synthesized using Au NP trimers as templates. Our experimental and computational results highlight the synergy of geometry and composition in plasmonic catalysts for plasmon-driven chemical reactions.
Research into integrating the concept of the internet of things (IoT) into smart factories has accelerated, leading to the emergence of various smart factory solutions. Most ideas, however, focus on ...the automation and integration of processes in factory, rather than organic cooperation among mobile assets (e.g., the workers and manufactured products) and fixed manufacturing equipment (e.g., press molds, computer numerical controls, painting). Additionally, it is difficult to apply smart factory and IoT designs to analog factories, because such a factory would require the integration of mobile assets and smart manufacturing processes. Thus, existing analog factories remain intact and smart factories are newly constructed. To overcome this disparity and to make analog factories compatible with smart technologies and IoT, we propose the opportunistic and location-based collaboration architecture (OLCA) platform, which allows for smart devices to be attached to workers, products, and facilities to enable the collaboration of location and event information in devices. Using this system, we can monitor workers' positions and production processes in real-time to help prevent dangerous situations and better understand product movement. We evaluate the proposed OLCA platform's performance while using a simple smart factory scenario, thus confirming its suitability.
In effort to address the shortage of emergency medical care in Cameroon, the Yaoundé Emergency Center (CURY) was established in June, 2015 in Yaoundé, Cameroon. To evaluate its impact on the ...communities of Yaoundé, we assessed the changes in utilizations of emergency medical care since the establishment of the CURY. In 2014 the first survey was conducted on randomly selected 619 households (3,201 individuals) living in six health districts of Yaoundé. In 2017 the second quantitative survey was conducted on 622 households (3,472 individuals) using the same survey methods as the first survey. In both surveys, data on demographic information, socioeconomic status, and utilization of healthcare, including emergency care in the past year were collected on every member of the households via face-to-face interview. Data on two surveys were compared. Participants in the both surveys had similar age and gender distribution with mean age of 21-22 and 46% being male. In 2014 survey, healthcare utilization rates for emergency unit, outpatient, and hospitalization were 4.8%, 36.7%, and 10.0%, respectively. In 2017 survey, corresponding rates were 5.8%, 32.5%, and 9.2%%, respectively. The increase in the utilization of emergency unit between two surveys showed a marginal statistical significance (p = 0.08), while outpatient utilization showed statistically significant decrease from 2014 to 2017 survey (from 36.7% to 32.5%; p <0.001). After the establishment of a dedicated emergency medical center in Yaoundé, Cameroon, the utilization of emergency care was increased in the Yaoundé community. Further studies are warranted to examine the direct effect of the establishment of the CURY on healthcare utilization in Yaoundé.
Precise control over the topology of plasmonic metal–semiconductor heteronanostructures is essential for fully harnessing their plasmonic function and hence for designing innovative solar energy ...conversion platforms. Here, we present a rational synthesis strategy for the realization of plasmonic metal–semiconductor heteronanocrystals with intended configurations through the site-selective overgrowth of semiconductor Cu2O on desired sites of anisotropic Au nanocrystals. Both the exploitation of structural characteristics of Au nanocrystals and the selective stabilization of their surfaces are keys to the construction of heteronanocrystals with a specific configuration. Our approach can provide an opportunity to precisely explore the link between the solar energy conversion efficiency and the structure of heteronanocrystals as well as to obtain important insights into the underpinning mechanism. Heteronanocrystals produced by Cu2O overgrowth preferentially on the multiple high-curvature sites of Au nanocrystals exhibited prominent photocatalytic hydrogen production activity due to efficient charge separation by strong plasmon excitation at the Au–Cu2O interface and subsequent sustainable hot electron transfer from Au to Cu2O.
•Most Sub-Saharan African countries struggle with health information technology and thus lack accurate patient data.•Medical databases serve a critical function in assessing the quality of healthcare ...for a specific disease or within a specific healthcare delivery.•Healthcare data also provides a quantitative basis for the resource allocations, therefore, it is particularly essential to ensure the efficient management and delivery of health services in resource poor environments, like many African countries.
Most countries in Sub-Saharan Africa have struggled to utilize health information technology and thus lack in accurate patient data. This paper describes the method of collecting patient data and patient characteristics in an emergency centre in Yaoundé, Cameroon.
We developed an Epi InfoTM-based data entry form to collect data of the patients who visited the Centre des Urgences de Yaoundé (CURY) from January 2016 to June
2018. Demographic, clinical symptoms, treatments and outcome data were collected.
Additional data on the patients with multiple trauma, chest pain, sepsis/septic shock, and stroke were also collected.
During the study period, a total of 18,875 patients’ data were collected (44.5% women, median age of 36). Of the total patients, 2.4% had chest pain, 2.7% had stroke, 1.9% had sepsis/septic shock, and 1.6% had multiple trauma. About 6.0% patients received operation and majority of patients were discharged either normally (48.2%) or with continuity of care (26.3%). About 5.0% of patients were transferred to other hospital and 5.2% of patients were dead.
This study serves to broaden understanding of the emergency patients in Yaoundé, Cameroon.
Plasmonic metal–semiconductor hybrid photocatalysts have received much attention because of their wide light harvesting range and efficient charge carrier generation capability originating from ...plasmon energy transfer. Here, we introduce a plasmonic metal–semiconductor hybrid nanostructure consisting of a Au core–satellite assembly and crystalline TiO2. The formation of Au@TiO2–Au core–satellite assemblies using TiO2 as a spacer and the subsequent growth of outer TiO2 shells on the core–satellite assemblies, followed by calcination, successfully generated Au core–satellite assembly@TiO2 nanostructures. Exquisite control over the growth of the TiO2 interlayer enabled the regulation of the gap distance between the core and satellite Au nanocrystals within the same hybrid morphology. Due to the structural controllability of the present approach, the gap-distance-dependent plasmonic and photocatalytic properties of the hybrid nanostructures could be explored. The nanostructures possessing the most closely arranged Au nanocrystals showed high photocatalytic activity under visible to near-infrared light irradiation, which can be attributed to strong plasmon coupling between the core and satellite Au nanocrystals that can expedite the formation of intense plasmon energy and its transfer to TiO2.
PDF
