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1.
Artigo em Inglês | MEDLINE | ID: mdl-33444481

RESUMO

We report an electrochemical method for coupling biomass-derived C5/C6 compounds to value-added fuel precursors. Using only 2 % of equivalent charges, 2-methylfuran (2-MF) was oxidized to yield a cation radical, which readily reacted with 3-hexene-2,5-dione, a derivate of 2,5-dimethylfuran, to produce 3-(5-methylfuran-2-yl)hexane-2,5-dione. The product was converted to 4-ethylnonane (a component of biodiesel/jet fuel) in a single step in excellent yield. Importantly, the reaction was not sensitive to oxygen, and a trace amount of water was found to promote the reaction. Detailed mechanistic studies confirmed the proposed reaction pathways. Key to the mechanism is the radical generation that is enabled by electrochemistry. The radical is regenerated at the end of a reaction cycle to ensure chain propagation for an average of ca. 47 times, resulting in an apparent Faradaic efficiency of 4700 %.

2.
Mol Ther Oncolytics ; 19: 163-177, 2020 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-33209976

RESUMO

This study aimed to expand the competing endogenous RNA network in osteosarcoma (OS) involving hsa_circ_0085539 and its downstream target miR-526b-5p. The expression levels of circ_0085539, miR-526b-5p, and stress-associated endoplasmic reticulum protein 1 (SERP1) mRNA in OS tissues and cells were detected and analyzed by qRT-PCR. After that, the interrelationships between these three genetic materials were validated with a luciferase reporter assay system. The effect of the circ_0085539/miR-526b-5p/SERP1 axis on OS cell malignancy phenotypes was further assessed using in vitro assays, including cell counting kit-8 (CCK-8) assays, colony foci formation assays, wound-healing migration assays, and transwell invasion assays. To determine the function of circ_0085539 on OS tumor growth in vivo, a xenograft formation assay was performed. In OS tissues and cells, the expression of circ_0085539 and SERP1 was upregulated, while that of miR-526b-5p was downregulated. After experimental analyses, it was found that silencing circ_0085539 inhibited the aggression of OS in vivo and in vitro. Mechanistic investigations also revealed that circ_0085539 could sponge miR-526b-5p and that miR526b-5p could directly target SERP1. The cytological experiments in vitro demonstrated that miR-526b-5p could restore the effect of circ_0085539 in terms of promoting OS malignancy phenotypes by suppressing SERP1. Overall, the present study validated that hsa_circ_0085539 could promote the progression of OS by regulating miR-526b-5p/SERP1.

3.
Sci Rep ; 10(1): 17900, 2020 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-33087797

RESUMO

This study aimed to explore the association of tumor sidedness with the prognosis of patients with colon signet ring cell carcinoma (SRCC). Eligible patients were retrieved from the Surveillance, Epidemiology, and End Results database between 2004 and 2015. Cancer-specific survival (CSS) and overall survival (OS) were compared between patients with left-sided colon SRCC and those with right-sided lesions. A total of 2660 patients were included, among them, 1983 (74.5%) had right-sided colon SRCC. Compared to patients with left-sided colon SRCC, those who had the right-sided colon SRCC showed higher proportion of white race, female, aged ≥ 65 years, receiving total colectomy and ≥ 4 regional lymph node dissection; while had lower proportion of advanced AJCC stage. Besides, right-sided patients exhibited superior 5-year CSS (32.74% vs. 25.89%, P = 0.001) and OS (27.38% vs. 23.02%, P = 0.024) rates compared with left-sided ones. Multivariate analysis revealed that tumor sidedness was an independent prognostic factor. To be specific, patients with right-sided colon SRCC showed better CSS (HR: 0.873; 95% CI 0.777-0.981; P = 0.023) and OS (HR: 0.838; 95% CI 0.753-0.965; P = 0.002). Moreover, subgroup analysis demonstrated superior CSS and OS for right-sided patients in most subgroups. Tumor sidedness was an independent prognostic indicator for colon SRCC. Besides, patients with right-sided colon SRCC have superior prognosis than those with left-sided lesions.

4.
Cancer Cell Int ; 20: 485, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33041666

RESUMO

[This retracts the article DOI: 10.1186/s12935-019-1055-z.].

5.
Adv Mater ; 32(46): e2002853, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33020998

RESUMO

Mixing multimetallic elements in hollow-structured nanoparticles is a promising strategy for the synthesis of highly efficient and cost-effective catalysts. However, the synthesis of multimetallic hollow nanoparticles is limited to two or three elements due to the difficulties in morphology control under the harsh alloying conditions. Herein, the rapid and continuous synthesis of hollow high-entropy-alloy (HEA) nanoparticles using a continuous "droplet-to-particle" method is reported. The formation of these hollow HEA nanoparticles is enabled through the decomposition of a gas-blowing agent in which a large amount of gas is produced in situ to "puff" the droplet during heating, followed by decomposition of the metal salt precursors and nucleation/growth of multimetallic particles. The high active sites per mass ratio of such hollow HEA nanoparticles makes them promising candidates for energy and electrocatalysis applications. As a proof-of-concept, it is demonstrated that these materials can be applied as the cathode catalyst for Li-O2 battery operations with a record-high current density per catalyst mass loading of 2000 mA gcat. -1 , as well as good stability and durable catalytic activity. This work offers a viable strategy for the continuous manufacturing of hollow HEA nanomaterials that can find broad applications in energy and catalysis.

6.
Neurosurg Rev ; 2020 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-32918635

RESUMO

Postoperative cognitive dysfunction (POCD) involves patient memory and learning decline after surgery. POCD not only presents challenges for postoperative nursing and recovery but may also cause permanent brain damage for patients, including children and the aged, with vulnerable central nervous systems. Its occurrence is mainly influenced by surgical trauma, anesthetics, and the health condition of the patient. There is a lack of imaging and experimental diagnosis; therefore, patients can only be diagnosed by clinical observation, which may underestimate the morbidity, resulting in decreased treatment efficacy. Except for symptomatic support therapy, there is a relative lack of effective drugs specific for the treatment of POCD, because the precise mechanism of POCD remains to be determined. One current hypothesis is that postoperative inflammation promotes the progression of POCD. Accumulating research has indicated that overactivation of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasomes contribute to the POCD progression, suggesting that targeting NLRP3 inflammasomes may be an effective therapy to treat POCD. In this review, we summarize recent studies and systematically describe the pathogenesis, treatment progression, and potential treatment options of targeting NLRP3 inflammasomes in POCD patients.

7.
Sci Rep ; 10(1): 14126, 2020 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-32839528

RESUMO

This study aimed to assess the benefit of postoperative adjuvant chemotherapy in stage II-III colorectal signet ring cell carcinoma (SRCC). Qualified postoperative patients were extracted from Surveillance, Epidemiology, and End Results (SEER) database from 2004 until 2015. We collected 1675 patients in the research, and 936 patients were subjected to adjuvant chemotherapy group. The proportions of married status, male, rectal cancer, grade III/IV, AJCC stage III and radiotherapy were higher; While, the rates of white race, ≥ 65 years old and located in cecum-transverse colon were lower in patients of chemotherapy group compared to no chemotherapy group (all P < 0.05). K-M plots revealed significantly better OS of adjuvant chemotherapy group than no chemotherapy group (P < 0.001). Meanwhile, there was no significantly different in CSS between the two groups (P = 0.93). However, after adjusting for confounding factors by multivariable Cox regression analysis, receipt of postoperative chemotherapy was still associated with better CSS and OS (CSS: hazard ratio [HR] = 0.719, 95% CI 0.612-0.844, P < 0.001) ; (OS: HR = 0.618, 95% CI 0.537-0.713, P < 0.001). Patients with stage II/III colorectal SRCC could receive survival benefit from postoperative adjuvant chemotherapy.

8.
Sci Rep ; 10(1): 13310, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32764626

RESUMO

To compare the clinicopathological characteristics and survival outcomes of children and adult diagnosed with medullary thyroid carcinoma (MTC). MTC patients were extracted from the Surveillance, Epidemiology and End Results (SEER) database from 1998 to 2016, followed by stratification into pediatric (< 20 years) or adult (≥ 20 years) groups. In total, 2,197 patients (110 pediatric and 2087 adult) with MTC were identified. Pediatric patients were more likely to have localized stage (70.0% vs. 51.6%), negative regional nodes (48.2% vs. 30.8%) and receive total/subtotal thyroidectomy surgery (97.3% vs. 85.3%). Moreover, CSS and OS rates were significantly higher in pediatric patients (both P < 0.001). Multivariable Cox regression analysis revealed that adult patients were significantly correlated with worse CSS and OS rates [(CSS: HR 11.60, 95% CI 1.62-83.02, P = 0.015); (OS: HR 5.63, 95% CI 2.08-15.25, P = 0.001)]. Further stratified analysis indicated that pediatric group might have significant better CSS and OS for patients with more advanced stage. Patients in the pediatric group were more likely to have earlier stage. Moreover, the prognosis of pediatric MTC patients was significantly better than that in adult patients.

9.
Sci Adv ; 6(25): eaba3809, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32596455

RESUMO

The preferential oxidation of CO (PROX) in hydrogen-rich fuel gas streams is an attractive option to remove CO while effectively conserving energy and H2. However, high CO conversion with concomitant high selectivity to CO2 but not H2O is challenging. Here, we report the synthesis of high-loading single Pt atom (2.0 weight %) catalysts with oxygen-bonded alkaline ions that stabilize the cationic Pt. The synthesis is performed in aqueous solution and achieves high Pt atom loadings in a single-step incipient wetness impregnation of alumina or silica. Promisingly, these catalysts have high CO PROX selectivity even at high CO conversion (~99.8% conversion, 70% selectivity at 110°C) and good stability under reaction conditions. These findings pave the way for the design of highly efficient single-atom catalysts, elucidate the role of ─OH species in CO oxidation, and confirm the absence of a support effect for our case.

10.
J Plast Surg Hand Surg ; 54(4): 195-199, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32530351

RESUMO

Background: Nerve block shows some potential in alleviating pain after mammaplasty. This systematic review and meta-analysis aims to investigate the efficacy of nerve block for pain control after mammaplasty.Methods: The databases including PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases are systematically searched for collecting the randomized controlled trials (RCTs) regarding the impact of nerve block on pain intensity after mammaplasty.Results: This meta-analysis has included four RCTs. Compared with the control group after mammaplasty, nerve block results in remarkably reduced pain scores. At 1, 3, and 6 h, the scores are -1.84; -2.49 to -1.20 (mean difference (MD; 95% confidence interval (CI)); p < .00001, -1.04; -1.47 to -0.62; p < .00001; and -0.96; -1.48 to -0.43; p = .0004, respectively. At 24 h, nerve block shows no significant impact on pain scores: 0.31; -1.05 to 0.43; p = .41. The standard MD of analgesic consumption is significantly reduced after nerve block: -1.27; -1.73 to -0.82; p < .00001.Conclusions: Nerve block is associated with substantially reduced pain intensity at 1 h, 3 h, and 6 h, as well as decreased analgesic consumption after mammaplasty. Therefore, a nerve block is a valuable tool for postoperative care after mammaplasty and should be recommended for the surgery.

11.
PeerJ ; 8: e8512, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32117621

RESUMO

Objectives: The survival benefit of postmastectomy radiotherapy (PMRT) has not been fully proven in inflammatory breast cancer (IBC). Thus, in the present research, we aimed at elucidating the effects of PMRT on the survival of IBC patients. Methods: Eligible patients were collected from the Surveillance, Epidemiology, and End Results (SEER) dataset between 2010 and 2013. The Kaplan-Meier method along with the log-rank test was utilized for the comparison of both the overall survival (OS) andthe cancer-specific survival (CSS) in patients undergoing PMRT or not. Additionally, multivariate survival analysis of CSS and OS were performed using the Cox proportional hazard model. Results: In total, 293 eligible cases were identified, with the median follow-up time of 27 months (range: 5-59 months). After propensity score matching (PSM), 188 patients (94 for each) were classified intothe No-PMRT and the PMRT group. Consequently, significantly higher OS rates were detected in the PMRT group compared with the No-PMRT group prior to PSM (P = 0.034), and significantly higher CSS (P = 0.013) and OS (P = 0.0063) rates were observed following PSM. Furthermore, multivariate analysis revealed thatPMRT [CSS (HR: 0.519, 95% CI [0.287-0.939], P = 0.030); OS (HR: 0.480, 95% CI [0.269-0.859], P = 0.013)], as well as Her2+/HR+ subtype, was independent favorable prognostic factors.Besides, black ethnicity, AJCC stage IV and triple-negative subtype were independent unfavorable prognostic factors. Further subgroup analysis revealed that most of the study population could benefit from PMRT, no matter OS or CSS. Conclusions: Our findings support that PMRT could improve the survival of IBC patients.

12.
PeerJ ; 7: e7837, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31632852

RESUMO

Objective: The study was designed to construct and validate a nomogram for predicting overall survival (OS) of male breast cancer (MBC) patients with infiltrating duct carcinoma (IDC). Methods: The cohort was selected from the Surveillance, Epidemiology, and End Results (SEER) database between January 1, 2004 and December 31, 2013. Univariate and multivariate Cox proportional hazard (PH) regression models were performed. A nomogram was developed based on the significant prognostic indicators of OS. The discriminatory and predictive capacities of nomogram were assessed by Harrell's concordance index (C-index), calibration plots, area under the curve (AUC) and the decision curve analysis (DCA). Results: The median and maximal survival time of 1862 eligible patients were 49 and 131 months, respectively. Multivariate analysis showed that age (P < 0.0001), marital status (P = 0.002), T stage (P < 0.0001), N stage (P = 0.021), M stage (P < 0.0001), progesterone receptor (PR) (P = 0.046), human epidermal growth factor receptor-2 (HER2) (P = 0.009), and chemotherapy (P = 0.003) were independent prognostic indicators of IDC of MBC. The eight variables were then combined to construct a 3-and 5-year nomogram. The C-indexes of the nomogram were0.740 (95% confidence interval [CI] [0.709-0.771]) and 0.718 (95% CI [0.672-0.764]) for the internal validation and external validation, respectively. A better discriminatory capacity was observed in the nomogram compared with the SEER summary stage (P < 0.001) and AJCC TNM staging systems (6th edition; P < 0.001) with respect to OS prediction. Good consistency was detected between the nomogram prediction and actual findings, as indicated by calibration curves. The AUC for 3-and 5-year OS was 0.739 (95% CI [0.693-0.786]) and 0.764 (95% CI [0.725-0.803]) in the training cohort and 0.737 (95% CI [0.671-0.803]) and 0.735 (95% CI [0.678-0.793]) in the validation cohort, respectively. The DCA demonstrated that the survival nomogram was clinically useful. Conclusions: The nomogram was able to more accurately predict 3-and 5-year OS of MBC patients with IDC histology than were existing models.

13.
J Chem Phys ; 151(13): 130902, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31594326

RESUMO

Solar water splitting promises a solution to challenges associated with the intermittent nature of solar energy. Of different implementations, photoelectrochemical water splitting, where one or more photoelectrodes harvest light and catalyze water splitting, represents a convenient platform to understand the governing principles of charge behaviors, especially at the light absorber|H2O interface. This Perspective recognizes and discusses the importance of the photoelectrode surface to solar water splitting performance. It presents discussions within the context of a prototypical water splitting material, Ta3N5, which has gained growing attention lately for its outstanding initial performance. Insights into the mechanisms by which Ta3N5 functions are presented, followed by examples of recent efforts to circumvent the issues that Ta3N5 decays rapidly under solar water splitting conditions. Our visions on the future directions of semiconductor-based solar water splitting will be presented at the end.

14.
Angew Chem Int Ed Engl ; 58(43): 15313-15317, 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31478284

RESUMO

The incompatibility between the anode and the cathode chemistry limits the used of Mg as an anode. This issue may be addressed by separating the anolyte and the catholyte with a membrane that only allows for Mg2+ transport. Mg-MOF-74 thin films were used as the separator for this purpose. It was shown to meet the needs of low-resistance, selective Mg2+ transport. The uniform MOF thin films supported on Au substrate with thicknesses down to ca. 202 nm showed an intrinsic resistance as low as 6.4â€…Ω cm2 , with the normalized room-temperature ionic conductivity of ca. 3.17×10-6  S cm-1 . When synthesized directly onto a porous anodized aluminum oxide (AAO) support, the resulting films were used as a standalone membrane to permit stable, low-overpotential Mg striping and plating for over 100 cycles at a current density of 0.05 mA cm-2 . The film was effective in blocking solvent molecules and counterions from crossing over for extended period of time.

15.
ACS Cent Sci ; 5(8): 1461-1467, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31482129

RESUMO

CO2 electrochemical reduction is of great interest not only for its technological implications but also for the scientific challenges it represents. How to suppress the kinetically favored hydrogen evolution in the presence of H2O, for instance, has attracted significant attention. Here we report a new way of achieving such a goal. Our strategy involves a unique water-in-salt electrolyte system, where the H2O concentration can be greatly suppressed due to the strong solvation of the high-concentration salt. More importantly, the water-in-salt electrolyte offers an opportunity to tune the H2O concentration for electrokinetic studies of CO2 reduction, a parameter of critical importance to the understanding of the detailed mechanisms but difficult to vary previously. Using Au as a model catalyst platform, we observed a zeroth-order dependence of the reaction rate on the H2O concentration, strongly suggesting that electron transfer, rather than concerted proton electron transfer, from the electrode to the adsorbed CO2 is the rate-determining step. The results shed new light on the mechanistic understanding of CO2 electrochemical reduction. Our approach is expected to be applicable to other catalyst systems, as well, which will offer a new dimension to mechanistic studies by tuning H2O concentrations.

16.
Phys Chem Chem Phys ; 21(32): 17517-17520, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31380550

RESUMO

Kinetic studies of photo- and photoelectro-catalysis fixation of CO2 are rare. Herein, a typical CO2 reduction addition to trans-stilbene is studied. Through Tafel analyses, the reaction rate-determining step (RDS) is identified as the first step of an anion free radical generation from the substrate, and the reaction order is 0.5.

17.
Breast Cancer Res Treat ; 178(2): 379-388, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31414242

RESUMO

OBJECTIVES: The aim of this analysis was to study the impact of marital status on inflammatory breast cancer (IBC) patients, as the prognostic impact is yet to be studied in detail. METHODS: Data of IBC patients from 2004 to 2010 were sorted out from the database of surveillance, epidemiology, and end results (SEER), and overall survival (OS) rates and breast cancer-specific survival (CSS) rates were compared between a group of married and unmarried patients. The comparison was performed by Kaplan-Meier method with log-rank test, and multivariate survival analysis of CSS and OS was performed using the Cox proportional hazard model. RESULTS: Data of 1342 patients were collected from the SEER database, on an average 52% of married patients (n = 698, 52.01%) and 48% of unmarried patients (n = 644, 47.99%) for this analysis. Married patients were more likely to be more younger (aged ≤ 56) (52.44% vs. 43.94%), white ethnicity (83.24% vs. 71.58%), HoR positive (48.28% vs. 41.61%), more patients received surgery (78.51% vs. 64.60%), chemotherapy (90.69% vs. 80.12%) and radiotherapy (53.44% vs. 44.41%) compared to unmarried group, and less likely to be AJCC stage IV (26.22% vs. 35.40%) (All P ˂ 0.05). Married patients had better 5-year CSS (74.90% vs. 65.55%, P < 0.0001) and OS rates (45.43% vs. 33.11%, P < 0.0001). The multivariate analysis revealed that marital status is an independent prognostic factor, whereas the data of unmarried patients showed worse CSS (HR 1.188; 95% CI 1.033-1.367; P = 0.016) and OS rates (HR 1.245; 95% CI 1.090-1.421; P = 0.001).The subgroup analysis further revealed that the OS and CSS rates in the married group were better than the unmarried group, regardless of different AJCC stages. CONCLUSION: Marital status was an independent prognostic indicator in IBC patients. As the study reveals, the CSS and OS rates of the married patients were better than those of the unmarried patients.


Assuntos
Neoplasias Inflamatórias Mamárias/epidemiologia , Estado Civil , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Bases de Dados Factuais , Modelos Animais de Doenças , Suscetibilidade a Doenças , Feminino , Humanos , Neoplasias Inflamatórias Mamárias/diagnóstico , Neoplasias Inflamatórias Mamárias/mortalidade , Neoplasias Inflamatórias Mamárias/terapia , Estimativa de Kaplan-Meier , Pessoa de Meia-Idade , Gradação de Tumores , Estadiamento de Neoplasias , Vigilância da População , Prognóstico , Modelos de Riscos Proporcionais , Medição de Risco , Fatores de Risco , Programa de SEER , Adulto Jovem
18.
Nano Lett ; 19(8): 5149-5158, 2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31313586

RESUMO

Nanostructured catalysts often face an important challenge: poor stability. Many factors contribute to catalytic degradation, including parasitic chemical reactions, phase separation, agglomeration, and dissolution, leading to activity loss especially during long-term catalytic reactions. This challenge is shared by a new family of catalysts, multimetallic nanoparticles, which have emerged owing to their broad tunability and high activity. While significant synthesis-based advances have been made, the stability of these nanostructured catalysts, especially during catalytic reactions, has not been well addressed. In this study, we reveal the critical influence of a synthetic method on the stability of nanostructured catalysts through aprotic oxygen catalysis (Li-O2 battery) demonstrations. In comparison to the conventional wet impregnation (WI) method, we show that the carbothermal shock (CTS) method dramatically improves the overall structural and chemical stability of the catalyst with the same elemental compositions. For multimetallic compositions (4- and 8-elements), the overall stability of the electrocatalysts as well as the battery lifetime can be further improved by incorporating additional noncatalytically active elements into the individual nanoparticles via CTS. The results offer a new synthetic path toward the stabilization of nanostructured catalysts, where additional reaction schemes beyond oxygen electrocatalysis are foreseeable.

19.
Medicine (Baltimore) ; 98(24): e15904, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31192924

RESUMO

RATIONALE: Classic laryngeal mask airway (LMA) has long been used for airway management. The LMA Supreme is a modified single-use version of the LMA Proseal, but it still remains some deficits such as the instable positioning that lead to easily sliding and the mask bowl full of air might lead to the reduced blood flow of the internal carotid artery. The carotid sinus is a baroreceptor that responds to the stretching of the arterial wall. Manual pressure of the carotid artery at the upper margin of the sternocleidomastoid muscle provoked bradycardia and hypotension. PATIENT CONCERNS: A previously fit and well 42-year-old woman presented with breast fibroma on the left side. No other disease history could be recorded. Her family history was negative for neuromuscular and autoimmune disease. DIAGNOSES: The patient suffered from a severe bradycardia and hypotension when the LMA showed a shift. We presented with a hypothetical that the dislocated LMA may cause carotid sinus syndrome (CSS). INTERVENTIONS: The patient's heart rate (HR) gradually rosed up as soon as the LMA adjusted back to the normal position. OUTCOMES: The patient was comfortable in the post anesthesia care unit (PACU) and had no adverse sequelae. LESSONS: The position of LMA Supreme should be confirmed throughout the surgery especially for the ones who has changed the position and the head was covered by surgical drapes.


Assuntos
Bradicardia/etiologia , Estenose das Carótidas/etiologia , Hipotensão/etiologia , Máscaras Laríngeas/efeitos adversos , Adulto , Feminino , Humanos
20.
ACS Appl Mater Interfaces ; 11(17): 15457-15466, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30964262

RESUMO

Tantalum nitride is a promising photoanode material for solar water splitting, but further study and practical use are constrained by the harsh conditions of the synthesis from Ta metal. Here, we report the direct deposition of crystalline Ta3N5 on fluorine-doped tin oxide (FTO) substrate via a custom-built atomic layer deposition (ALD) system. A combination of TaCl5 (Ta precursor) and ammonia (N source) was sequentially pulsed into the ALD reactor with the substrate heated to 550 °C to deposit compact and thin films of Ta3N5 with controllable thicknesses on FTO substrates. Importantly, it is shown that the FTO is chemically and structurally stable under the reducing conditions of ammonia at 550 °C. These electrodes produced an exceptional photocurrent onset potential of ∼0.3 V versus reversible hydrogen electrode (RHE) with a maximum photocurrent of ∼2.4 mA cm-2 at 1.23 V versus RHE. Results of photoelectrochemical investigations as a function of film thickness and illumination direction reveal that the performance of Ta3N5 is controlled by a hole diffusion length of ∼50 nm. These results are crucial for the successful integration of Ta3N5 in efficient unassisted water-splitting applications.

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