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1.
Small ; : e2401230, 2024 May 02.
Article in English | MEDLINE | ID: mdl-38698589

ABSTRACT

Control over the morphology of nanomaterials to have a 2D structure and manipulating the surface strain of nanostructures through defect control have proved to be promising for developing efficient catalysts for sustainable chemical and energy conversion. Here a one-pot aqueous synthesis route of freestanding Pd nanosheets with a penta-twinned structure (PdPT NSs) is presented. The generation of the penta-twinned nanosheet structure can be succeeded by directing the anisotropic growth of Pd under the controlled reduction kinetics of Pd precursors. Experimental and computational investigations showed that the surface atoms of the PdPT NSs are effectively under a compressive environment due to the strain imposed by their twin boundary defects. Due to the twin boundary-induced surface strain as well as the 2D structure of the PdPT NSs, they exhibited highly enhanced electrocatalytic activity for oxygen reduction reaction compared to Pd nanosheets without a twin boundary, 3D Pd nanocrystals, and commercial Pd/C and Pt/C catalysts.

2.
J Am Chem Soc ; 145(43): 23639-23650, 2023 Nov 01.
Article in English | MEDLINE | ID: mdl-37850865

ABSTRACT

Photoanodes used in a water-splitting photoelectrochemical cell are almost always paired with an oxygen evolution catalyst (OEC) to efficiently utilize photon-generated holes for water oxidation because the surfaces of photoanodes are typically not catalytic for the water oxidation reaction. Suppressing electron-hole recombination at the photoanode/OEC interface is critical for the OEC to maximally utilize the holes reaching the interface for water oxidation. In order to explicitly demonstrate and investigate how the detailed features of the photoanode/OEC interface affect interfacial charge transfer and photocurrent generation for water oxidation, we prepared two BiVO4(010)/FeOOH photoanodes with different Bi:V ratios at the outermost layer of the BiVO4 interface (close to stoichiometric vs Bi-rich) while keeping all other factors in the bulk BiVO4 and FeOOH layers identical. The resulting two photoanodes show striking differences in the photocurrent onset potential and photocurrent density for water oxidation. The ambient pressure X-ray photoelectron spectroscopy results show that these two BiVO4(010)/FeOOH photoanodes show drastically different Fe2+:Fe3+ ratios in FeOOH both in the dark and under illumination with water, demonstrating the immense impact of the interfacial composition and structure on interfacial charge transfer. Using computational studies, we reveal the effect of the surface Bi:V ratio on the hydration of the BiVO4 surface and bonding with the FeOOH layer, which in turn affect the band alignments between BiVO4 and FeOOH. These results explain the atomic origin of the experimentally observed differences in electron and hole transfer and solar water oxidation performance of the two photoanodes having different interfacial compositions.

3.
ACS Nano ; 17(18): 18641-18651, 2023 Sep 26.
Article in English | MEDLINE | ID: mdl-37702701

ABSTRACT

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.

4.
Am J Emerg Med ; 73: 125-130, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37651762

ABSTRACT

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

5.
Nat Commun ; 13(1): 5957, 2022 Oct 10.
Article in English | MEDLINE | ID: mdl-36216798

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.

6.
Afr J Emerg Med ; 12(1): 77-84, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35116221

ABSTRACT

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.

7.
ACS Nano ; 15(3): 4066-4076, 2021 Mar 23.
Article in English | MEDLINE | ID: mdl-33506675

ABSTRACT

The structures as building blocks for designing functional nanomaterials have fueled the development of versatile nanoprobes to understand local structures of noncrystalline specimens. Progress in analyzing structures of individual specimens with atomic scale accuracy has been notable recently. In most cases, however, only a limited number of specimens are inspected lacking statistics to represent the systems with structural inhomogeneity. Here, by employing single-particle imaging with X-ray free electron lasers and algorithms for multiple-model 3D imaging, we succeeded in investigating several thousand specimens in a couple of hours and identified intrinsic heterogeneities with 3D structures. Quantitative analysis has unveiled 3D morphology, facet indices, and elastic strain. The 3D elastic energy distribution is further corroborated by molecular dynamics simulations to gain mechanical insight at the atomic level. This work establishes a route to high-throughput characterization of individual specimens in large ensembles, hence overcoming statistical deficiency while providing quantitative information at the nanoscale.

8.
Clin Exp Emerg Med ; 6(3): 242-249, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31571440

ABSTRACT

OBJECTIVE: High cholesterol level is a risk factor for coronary artery disease, and coronary artery disease is a major risk factor for out-of-hospital cardiac arrest (OHCA). However, the effect of cholesterol level on outcomes of OHCA has been poorly studied. This study aimed to determine the effect of cholesterol level on outcomes of OHCA. METHODS: This cross-sectional study used the CAPTURES (Cardiac Arrest Pursuit Trial with Unique Registration and Epidemiologic Surveillance) project database in Korea. Multivariable conditional logistic regression analysis was performed to estimate the effect of cholesterol level on outcomes in OHCA. RESULTS: In all, 584 cases of OHCA were analyzed; those with cholesterol levels <120 mg/dL were classified as having low total cholesterol (TC) (n=197), those with levels ranging from 120-199 mg/dL as middle TC (n=322), and those with ≥200 mg/dL as high TC (n=65). Compared to low TC, more patients with middle TC and high TC survived to discharge (9.1% vs. 22.0% and 26.2%, respectively, P=0.001). The good cerebral performance category also increased in that order (4.1 % vs. 14.6% and 23.1%, respectively, P≤0.001). Comparing middle TC and high TC with low TC, adjusted odds ratios (95% confidence intervals) were 1.97 (1.06 to 3.64) and 2.53 (1.08 to 5.92) for survival to discharge, respectively, and 2.53 (1.07 to 5.98) and 4.73 (1.63 to 13.71) for good neurological recovery, respectively. CONCLUSION: Higher cholesterol is associated with better outcomes in OHCA; cholesterol level is a good predictor of outcomes of OHCA.

9.
PLoS One ; 14(2): e0211777, 2019.
Article in English | MEDLINE | ID: mdl-30735533

ABSTRACT

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.


Subject(s)
Delivery of Health Care , Emergency Medical Services , Emergency Service, Hospital , Hospitalization , Patient Acceptance of Health Care , Adolescent , Adult , Aged , Cameroon , Child , Child, Preschool , Cross-Sectional Studies , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged
10.
Clin Exp Emerg Med ; 6(4): 321-329, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31910503

ABSTRACT

OBJECTIVE: This study aimed to compare the demographic characteristics and trauma service structures and processes of hospitals in 15 countries across the Asia Pacific, and to provide baseline data for the integrated trauma database: the Pan-Asian Trauma Outcomes Study (PATOS). METHODS: Medical directors and emergency physicians at PATOS-participating hospitals in countries across the Asia Pacific were surveyed through a standardized questionnaire. General information, trauma care system data, and trauma emergency department (ED) outcomes at each hospital were collected by email and analyzed using descriptive statistics. RESULTS: Survey data from 35 hospitals across 15 countries were collected from archived data between June 2014 and July 2015. Designated trauma centers were identified as the highest hospital level for trauma patients in 70% of surveyed countries. Half of the hospitals surveyed had special teams for trauma care, and almost all prepared activation protocol documents for these teams. Most hospitals offered specialized trauma education programs, and 72.7% of hospitals had a hospital-based trauma registry. The total number of trauma patients visiting the ED across 25 of the hospitals was 300,376. The overall survival-to-discharge rate was 97.2%; however, it varied greatly between 85.1% and 99.7%. The difference between survival-to-discharge rates of moderate and severe injury groups was highest in Taiwan (41.8%) and lowest in Thailand (18.6%). CONCLUSION: Trauma care systems and ED outcomes vary widely among surveyed hospitals and countries. This information is useful to build further detailed, systematic platforms for trauma surveillance and evidence-based trauma care policies.

11.
Sensors (Basel) ; 18(8)2018 Aug 17.
Article in English | MEDLINE | ID: mdl-30126095

ABSTRACT

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.

12.
Resuscitation ; 131: 29-35, 2018 10.
Article in English | MEDLINE | ID: mdl-30063962

ABSTRACT

OBJECTIVES: We aimed to evaluate the associations between the centralization of dispatch centers and dispatcher-assisted bystander cardiopulmonary resuscitation (DA-BCPR) for out-of-hospital cardiac arrest (OHCA) patients. METHODS: All emergency medical services (EMS)-treated adults in Gyeonggi province (34 fire departments covering 43 counties, with a population of 12.6 million) with OHCAs of cardiac etiology were enrolled between 2013 and 2016, excluding cases witnessed by EMS providers. In Gyeonggi province, 34 agency-based dispatch centers were sequentially integrated into two province-based central dispatch centers (north and south) between November 2013 and May 2016. Exposure was the centralization of the dispatch centers. Endpoint variables were BCPR and dispatcher-provided CPR instructions. Generalized linear mixed models for multilevel regression analyses were performed. RESULTS: Overall, 11,616 patients (5060 before centralization and 6556 after centralization) were included in the final analysis. The OHCAs that occurred during the after-centralization period were more likely to receive BCPR (62.6%, 50.6% BCPR-with-DA and 12.0% BCPR-without-DA) than were those that occurred before-centralization period (44.6%, 16.6% BCPR-with-DA and 28.1% BCPR-without-DA) (p < 0.01, adjusted OR: 1.59 (1.38-1.83), adjusted rate difference: 9.1% (5.0-13.2)). For dispatcher-provided CPR instructions, OHCAs diagnosed at a higher rate during the after-centralization period than during the before-centralization period (67.4% vs. 23.1%, p < 0.01, adjusted OR: 4.57 (3.26-6.42), adjusted rate difference: 30.3% (26.4-34.2)). The EMS response time was not different between the groups (p=0.26). CONCLUSIONS: The centralization of dispatch centers was associated with an improved bystander CPR rate and dispatcher-provided CPR instructions for OHCA patients.


Subject(s)
Cardiopulmonary Resuscitation/methods , Emergency Medical Dispatch/organization & administration , Emergency Medical Dispatcher/statistics & numerical data , Out-of-Hospital Cardiac Arrest/therapy , Aged , Cardiopulmonary Resuscitation/statistics & numerical data , Female , Humans , Male , Middle Aged , Out-of-Hospital Cardiac Arrest/diagnosis , Out-of-Hospital Cardiac Arrest/mortality , Prospective Studies , Registries
13.
Nanoscale ; 10(23): 10835-10843, 2018 Jun 14.
Article in English | MEDLINE | ID: mdl-29694476

ABSTRACT

The intrinsic correlation between an enhancement of catalytic activity and the flow of hot electrons generated at metal-oxide interfaces suggests an intriguing way to control catalytic reactions and is a significant subject in heterogeneous catalysis. Here, we show surface plasmon-induced catalytic enhancement by the peculiar nanocatalyst design of hexoctahedral (HOH) Au nanocrystals (NCs) with Cu2O clusters. We found that this inverse catalyst comprising a reactive oxide for the catalytic portion and a metal as the source of electrons by localized surface plasmon resonance (localized SPR) exhibits a change in catalytic activity by direct hot electron transfer or plasmon-induced resonance energy transfer (PIRET) when exposed to light. We prepared two types of inverse catalysts, Cu2O at the vertex sites of HOH Au NCs (Cu2O/Au vertex site) and a HOH Au NC-Cu2O core-shell structure (HOH Au@Cu2O), to test the structural effect on surface plasmons. Under broadband light illumination, the Cu2O/Au vertex site catalyst showed 30-90% higher catalytic activity and the HOH Au@Cu2O catalyst showed 10-30% higher catalytic activity than when in the dark. Embedding thin SiO2 layers between the HOH Au NCs and the Cu2O verified that the dominant mechanism for the catalytic enhancement is direct hot electron transfer from the HOH Au to the Cu2O. Finite-difference time domain calculations show that a much stronger electric field was formed on the vertex sites after growing the Cu2O on the HOH Au NCs. These results imply that the catalytic activity is enhanced when hot electrons, created from photon absorption on the HOH Au metal and amplified by the presence of surface plasmons, are transferred to the reactive Cu2O.

14.
Prehosp Emerg Care ; 22(1): 58-83, 2018.
Article in English | MEDLINE | ID: mdl-28792281

ABSTRACT

BACKGROUND: Trauma is a major health burden and a time-dependent critical emergency condition among developing and developed countries. In Asia, trauma has become a rapidly expanding epidemic and has spread out to many underdeveloped and developing countries through rapid urbanization and industrialization. Most casualties of severe trauma, which results in significant mortality and disability are assessed and transported by prehospital providers including physicians, professional providers, and volunteer providers. Trauma registries have been developed in mostly developed countries and measure care quality, process, and outcomes. In general, existing registries tend to focus on inhospital care rather than prehospital care. METHODS: The Pan-Asia Trauma Outcomes Study (PATOS) was proposed in 2013 and initiated in November, 2015 in order to establish a collaborative standardized study to measure the capabilities, processes and outcomes of trauma care throughout Asia. The PATOS is an international, multicenter, and observational research network to collect trauma cases transported by emergency medical services (EMS) providers. Data are collected from the participating hospital emergency departments in various countries in Asia which receive trauma patients from EMS. Data variables collected include 1) injury epidemiologic factors, 2) EMS factors, 3) emergency department care factors, 4) hospital care factors, and 5) trauma system factors. The authors expect to achieve a sample size of 67,230 cases over the next 2 years of data collection to analyze the association between potential risks and outcomes of trauma. CONCLUSION: The PATOS network is expected to provide comparison of the trauma EMS systems and to benchmark best practice with participating communities.


Subject(s)
Emergency Medical Services/statistics & numerical data , Emergency Service, Hospital/statistics & numerical data , Registries/statistics & numerical data , Wounds and Injuries/epidemiology , Asia/epidemiology , Data Collection/methods , Delivery of Health Care/statistics & numerical data , Female , Humans , Male , Quality of Health Care , Survival Rate , Wounds and Injuries/therapy
15.
J Korean Med Sci ; 32(12): 1931-1937, 2017 Dec.
Article in English | MEDLINE | ID: mdl-29115073

ABSTRACT

Development of a competence-based curriculum is important. This study aimed to develop competence assessment tools in emergency medicine and use it to assess competence of Cameroonian healthcare professionals. This was a cross-sectional, descriptive study. Through literature review, expert survey, and discrimination tests, we developed a self-survey questionnaire and a scenario-based competence assessment tool for assessing clinical knowledge and self-confidence to perform clinical practices or procedures. The self-survey consisted of 23 domains and 94 questionnaires on a 5-point Likert scale. Objective scenario-based competence assessment tool was used to validate the self-survey results for five life-threatening diseases presenting frequently in emergency rooms of Cameroon. Response rate of the self-survey was 82.6%. In this first half of competence assessment, knowledge of infectious disease had the highest score (4.6 ± 0.4) followed by obstetrics and gynecology (4.2 ± 0.6) and hematology and oncology (4.2 ± 0.5); in contrast, respondents rated the lowest score in the domains of disaster, abuse and assault, and psychiatric and behavior disorder (all of mean 2.8). In the scenario-based test, knowledge of multiple trauma had the highest score (4.3 ± 1.2) followed by anaphylaxis (3.4 ± 1.4), diabetic ketoacidosis (3.3 ± 1.0), ST-elevation myocardial infarction (2.5 ± 1.4), and septic shock (2.2 ± 1.1). Mean difference between the self-survey and scenario-based test was statistically insignificant (mean, -0.02; 95% confidence interval, -0.41 to 0.36), and agreement rate was 58.3%. Both evaluation tools showed a moderate correlation, and the study population had relatively low competence for specific aspects of emergency medicine and clinical procedures and skills.


Subject(s)
Clinical Competence , Emergency Medicine/education , Health Personnel/psychology , Area Under Curve , Cameroon , Cross-Sectional Studies , Humans , Program Evaluation , ROC Curve , Surveys and Questionnaires
16.
Prehosp Emerg Care ; 21(2): 242-251, 2017.
Article in English | MEDLINE | ID: mdl-27918864

ABSTRACT

OBJECTIVE: Knowledge on the current trauma systems in Asian countries is limited. The objective of this study was to describe the emergency medical services (EMS) and trauma care systems among countries participating in the Pan-Asian Trauma Outcomes Study (PATOS) Clinical Research Network. METHODS: The PATOS network consists of 33 participating sites from 14 countries. Standardized data was collected from each site using an EMS survey form and included general information (population, population density, urbanization, EMS service fee, etc.), dispatcher system, trauma care practice, trauma education program, existence of a trauma registry, and data on EMS transfers. Data is described with simple descriptive statistics. RESULTS: All countries included urban sites. Nine countries included rural sites and only one country included wilderness site. Of the 33 sties, 18 sites had physician-based EMS systems. EMS services were free in 9 countries. Twelve sites had dispatch centers operated by government health departments. EMS dispatcher certification was required in 29 sites. Thirty-two sites had EMS documented protocols for trauma and 31 sites had field triage tools. Thirty sites had designated trauma centers. Twenty-one sites had helicopter EMS systems. Thirty-one sites require certification for trauma education programs. Only 23 sites maintained EMS-based trauma registries. In 20 sites, EMS medical directors reviewed and assured trauma registry quality. Of patients transported by EMS rate of injured patients ranged from 15% to 59%. CONCLUSION: Substantial variability exists in EMS systems in Asia, especially for injured patients. Futures studies are required to assess the impact of this variability on patient outcomes.


Subject(s)
Emergency Medical Services/statistics & numerical data , Trauma Centers/statistics & numerical data , Wounds and Injuries/epidemiology , Asia/epidemiology , Cost of Illness , Emergency Medical Services/organization & administration , Emergency Medical Services/standards , Internationality , Surveys and Questionnaires , Trauma Centers/organization & administration , Trauma Centers/standards , Wounds and Injuries/therapy
17.
J Am Chem Soc ; 138(48): 15766-15773, 2016 12 07.
Article in English | MEDLINE | ID: mdl-27933998

ABSTRACT

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.

18.
Angew Chem Int Ed Engl ; 55(8): 2753-8, 2016 Feb 18.
Article in English | MEDLINE | ID: mdl-26799639

ABSTRACT

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.

19.
Article in Korean | WPRIM (Western Pacific) | ID: wpr-760753

ABSTRACT

OBJECTIVES: New adjacent spinal compression fractures occur not only in patients with osteoporotic spinal compression fractures after vertebroplasty but also in untreated old spinal compression fractures. The objective was to analyze and compare the characteristics in a group who had untreated old osteoporotic spinal compression fractures with those who had adjacent spinal compression fractures, which occurred after a vertebroplasty. MATERIALS & METHODS: From April 2006 to April 2009, 103 patients who had undergone vertebroplasty were evaluated. Eighteen patients (22 cases) who had untreated old osteoporotic spinal compression fractures were in group I, and 12 patients (13 cases) who had adjacent spinal compression fractures, which occurred after a vertebroplasty were in group II. In each group, we measured age and gender, body mass index (BMI), lumbar bone marrow density (BMD), sagittal index, and compression rate at the initial fracture site.


Subject(s)
Aged , Humans , Body Mass Index , Bone Marrow , Fractures, Compression , Orthotic Devices , Osteoporosis , Vertebroplasty
20.
J Ethnopharmacol ; 88(1): 79-83, 2003 Sep.
Article in English | MEDLINE | ID: mdl-12902055

ABSTRACT

Paljin-Hangahmdan is an Oriental herbal formulation under intensive investigation for its ability to modulate growth and survival in cancer cells. This research was performed to study the anticancer effects of Paljin-Hangahmdan water extract (PHWE) in human promyelocytic leukemia (HL-60) cells. After HL-60 cells were routinely cultured, tetrazolium-based colorimetric assay was performed for cytotoxicity test. Cytotoxicity of PHWE (200-800 microg/ml) in HL-60 cells was increased in a dose- and time-dependent manner. However, PHWE (200-800 microg/ml) had less cytotoxicity in peripheral blood mononuclear cells isolated from a healthy subject. To explore the mechanism of cytotoxicity, we used several measures of apoptosis to determine whether these processes were involved in PHWE-induced leukemic cell death. Our results showed PHWE induced the cell shrinkage, cell membrane blebbing, apoptotic body, and DNA fragmentation. In addition, the flow cytometric analysis revealed PHWE (200-800 microg/ml) dose-dependently increased apoptotic cells with hypodiploid DNA contents. These results indicate that PHWE can control leukemic HL-60 cells through apoptosis and may have a possibility of potential anticancer activities.


Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Antineoplastic Agents, Phytogenic/therapeutic use , Apoptosis/drug effects , HL-60 Cells , Medicine, East Asian Traditional , Plant Extracts/toxicity , Plant Extracts/therapeutic use , Animals , Antineoplastic Agents, Phytogenic/toxicity , Cell Survival , Herbal Medicine , Humans , Korea
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