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1.
Chempluschem ; 88(12): e202300413, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37796663

RESUMO

5-hydroxymethylfurfural represents a key chemical in the drive towards a sustainable circular economy within the chemical industry. The final step in 5-hydroxymethylfurfural production is the acid catalysed dehydration of fructose, for which supported organoacids are excellent potential catalyst candidates. Here we report a range of solid acid catalysis based on sulphonic acid grafted onto different porous silica nanosphere architectures, as confirmed by TEM, N2 porosimetry, XPS and ATR-IR. All four catalysts display enhanced active site normalised activity and productivity, relative to alternative silica supported equivalent systems in the literature, with in-pore diffusion of both substrate and product key to both performance and humin formation pathway. An increase in-pore diffusion coefficient of 5-hydroxymethylfurfural within wormlike and stellate structures results in optimal productivity. In contrast, poor diffusion within a raspberry-like morphology decreases rates of 5-hydroxymethylfurfural production and increases its consumption within humin formation.

2.
JACC Case Rep ; 15: 101867, 2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37283823

RESUMO

A toddler presented with hematemesis a few weeks after ingesting a penny. Workup revealed an esophageal lesion communicating with an aortic pseudoaneurysm in the setting of Actinomyces odontolyticus bacteremia. A. odontolytica is an oropharyngeal bacteria known to cause fistulas when introduced into tissue planes. (Level of Difficulty: Intermediate.).

3.
Dev Psychopathol ; : 1-11, 2023 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-36744532

RESUMO

Children who have experienced maltreatment are more likely to have disrupted attachments, fewer psychosocial strengths, and poorer long-term psychosocial outcomes. However, few studies have examined the interplay between attachment security and psychosocial strengths among children involved in therapeutic services in the context of the child welfare system. The present longitudinal study examines the insecure attachment behaviors and psychosocial strengths of 555 children referred to the Therapeutic Family Care program (TFCP) in Cobourg, Ontario between 2000 and 2019. The children were assessed by their caregivers on a regular basis using the Assessment Checklist for Children (ACC) and the complementary strengths-focused ACC+ measure. Average age of children at baseline was 9.57 years (SD = 3.51) and 229 (41.26%) were female. We conducted growth curve and random intercepts cross-lagged panel models to test the longitudinal interplay between insecure attachment behaviors and strengths. Results suggest that females' attachment security improved, males' attachment security worsened, and both males and females developed strengths over time. Further, analyses revealed a directional effect, whereby fewer insecure attachment behaviors predicted more psychosocial strengths approximately 6 months later. Implications for attachment-oriented and strengths-based services in the context of child welfare are discussed.

4.
Chem Soc Rev ; 51(24): 10083-10119, 2022 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-36416191

RESUMO

Inspired by natural mobile microorganisms, researchers have developed micro/nanomotors (MNMs) that can autonomously move by transducing different kinds of energies into kinetic energy. The rapid development of MNMs has created tremendous opportunities for biomedical fields including diagnostics, therapeutics, and theranostics. Although the great progress has been made in MNM research, at a fundamental level, the accepted propulsion mechanisms are still a controversial matter. In practical applications such as precision nanomedicine, the precise control of the motion, including the speed and directionality, of MNMs is also important, which makes advanced motion manipulation desirable. Very recently, diverse MNMs with different propulsion strategies, morphologies, sizes, porosities and chemical structures have been fabricated and applied for various uses. Herein, we thoroughly summarize the physical principles behind propulsion strategies, as well as the recent advances in motion manipulation methods and relevant biomedical applications of these MNMs. The current challenges in MNM research are also discussed. We hope this review can provide a bird's eye overview of the MNM research and inspire researchers to create novel and more powerful MNMs.


Assuntos
Nanoestruturas , Nanotecnologia , Nanoestruturas/química , Nanomedicina , Movimento (Física)
5.
Adv Mater ; 34(43): e2205153, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35999183

RESUMO

Hollow nanostructures with fascinating properties have inspired numerous interests in broad research fields. Cell-mimicking complex hollow architectures with precise active components distributions are particularly important, while their synthesis remains highly challenging. Herein, a "top-down" chemical surgery strategy is introduced to engrave the 3-aminophenol formaldehyde resin (APF) spheres at nanoscale. Undergoing the cleavage of (Ar)CN bonds with ethanol as chemical scissors and subsequent repolymerization process, the Solid APF transform to multilevel hollow architecture with precise nanospatial distribution of organic functional groups (e.g., hydroxymethyl and amine). The transformation is tracked by electron microscopy and solid-state nuclear magnetic resonance techniques, the category and dosage of alcohol are pivotal for constructing multilevel hollow structures. Moreover, it is demonstrated the evolution of nanostructures accompanied with unique organic microenvironments is able to accurately confine multiple gold (Au) nanoparticles, leading to the formation of pomegranate-like particles. Through selectively depositing palladium (Pd) nanoparticles onto the outer shell, bimetallic Au@APF@Pd catalysts are formed, which exhibit excellent hydrogenation performance with turnover frequency (TOF) value up to 11257 h-1 . This work provides an effective method for precisely manipulating the nanostructure and composition of polymers at nanoscale and sheds light on the design of catalysts with precise spatial active components.

6.
ACS Nano ; 16(2): 2852-2865, 2022 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-35099942

RESUMO

Chemotherapy is a primary cancer treatment strategy, the monitoring of which is critical to enhancing the survival rate and quality of life of cancer patients. However, current chemotherapy monitoring mainly relies on imaging tools with inefficient sensitivity and radiation invasiveness. Herein, we develop the bowl-shaped submicroreactor chip of Au-loaded 3-aminophenol formaldehyde resin (denoted as APF-bowl&Au) with a specifically designed structure and Au loading content. The obtained APF-bowl&Au, used as the matrix of laser desorption/ionization mass spectrometry (LDI MS), possesses an enhanced localized electromagnetic field for strengthened small metabolite detection. The APF-bowl&Au enables the extraction of serum metabolic fingerprints (SMFs), and machine learning of the SMFs achieves chemotherapy monitoring of ovarian cancer with area-under-the-curve (AUC) of 0.81-0.98. Furthermore, a serum metabolic biomarker panel is preliminarily identified, exhibiting gradual changes as the chemotherapy cycles proceed. This work provides insights into the development of nanochips and contributes to a universal detection platform for chemotherapy monitoring.


Assuntos
Qualidade de Vida , Soro , Humanos , Lasers , Polímeros , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos
7.
Small ; 17(49): e2103224, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34611983

RESUMO

Photocatalysis offers a sustainable strategy for hydrogen peroxide (H2 O2 ) production, which is an essential oxidant and emerging energy carrier in modern chemical industry. The development of polymer-based photocatalysts to produce H2 O2 has great potential but is limited by lower efficiency due to the limitation of light utilization and the low charge separation efficiency. Herein, a series of monodispersed mesoporous resorcinol-formaldehyde resin spheres (MRFS) are reported with a rational designed spatial charge distribution, exhibiting wide light absorption with a solar-to-chemical conversion (SCC) efficiency of 1.1%. Surface photovoltage microscopy (SPVM) measurements unraveled the charge separation in nanospace with uneven distribution of donor (D) and acceptor (A) sites. A density functional theory (DFT) calculation elucidated the origin of photogenerated electrons and holes. Moreover, MRFS demonstrates photocatalytic water oxidation ability. The findings in this work open a new avenue for the development of porous polymeric photocatalysts toward highly efficient solar energy conversion.

8.
Small ; 17(33): e2101271, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34254441

RESUMO

Nitrogen-doped nanocarbons are widely used as supports for metal-heterogeneous catalytic conversions. When nitrogen-doped nanocarbon supports are used to disperse metallic nanoparticles (MNPs), the nitrogen dopant can enhance MNPs electron density to reach higher catalytic activity and promote MNPs stability through anchoring effects. However, the precise identification of active nitrogen species between N-dopants and reactants is rarely reported. Herein, a proof-of-concept study on the active N species for levulinic acid hydrogenation is reported. A double-shell structured carbon catalyst (DSC) is designed with selectively locating ultrafine Ru NPs only on inner carbon shell, specifically, different N species on the external carbon shell. Through the design of such a nanostructure, it is demonstrated that the alkaline pyridinic N species on the outer shell serves as an anchor point for the spontaneous binding of the acidic reactant. The pyridinic N content can be modulated from 7.4 to 29.2 mg gcat-1 by selecting different precursors. Finally, the Ru-DSC-CTS (using chitosan as the precursor) catalyst achieves a 99% conversion of levulinic acid under 70 °C and 4 MPa hydrogen pressure for 1 h. This work sheds light on the design of nanoreactors at the atomic scale and investigates heterogeneous catalysis at the molecular level.


Assuntos
Ácidos Levulínicos , Nitrogênio , Hidrogenação , Nanotecnologia
9.
Small ; 17(9): e1906250, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32406190

RESUMO

Heterogeneous hydrogenation reactions are of great importance for chemical upgrading and synthesis, but still face the challenges of controlling selectivity and long-term stability. To improve the catalytic performance, many hydrogenation reactions utilize special yolk/core-shell nanoreactors (YCSNs) with unique architectures and advantageous properties. This work presents the developmental and technological challenges in the preparation of YCSNs that are potentially useful for hydrogenation reactions, and provides a summary of the properties of these materials. The work also addresses the scientific challenges in applications of these YCSNs in various gas and liquid-phase hydrogenation reactions. The catalyst structures, catalytic performance, structure-performance relationships, reaction mechanisms, and unsolved problems are discussed too. Also, a brief outlook and opportunities for future research in this field are presented. This work on the advancements in YCSNs might inspire the creation of new materials with desired structures for achieving maximal hydrogenation performances.


Assuntos
Nanotecnologia , Catálise , Hidrogenação
10.
ISA Trans ; 105: 256-268, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32487423

RESUMO

When drilling an oil or gas well, well pressures may be controlled using a technology called managed pressure drilling. This technology often relies on model predictive control schemes; however, practical limitations have generally led to the use of simplified controller models that do not optimally handle certain perturbations in the physical system. The present work reports on the first implementation of a highly accurate system model that has been adapted for real-time use in a controller. This real-time high-fidelity model approximates the results of offline high-fidelity models without requiring operation by model experts. The effectiveness of the model is demonstrated through simulation studies of controller behavior under various drilling conditions, including an evaluation of the impact of sparse downhole feedback measurements.

11.
Front Chem ; 7: 691, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31709225

RESUMO

Gold has long held the fascination of mankind. For millennia it has found use in art, cosmetic metallurgy and architecture; this element is seen as the ultimate statement of prosperity and beauty. This myriad of uses is made possible by the characteristic inertness of bulk gold; allowing it to appear long lasting and above the tarnishing experienced by other metals, in part providing its status as the most noble metal.

12.
Adv Sci (Weinh) ; 6(22): 1900807, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31763134

RESUMO

It is desirable to design nonprecious metal nanocatalysts with high stability and catalytic performance for fine chemicals production. Here, a method is reported for the preparation of cobalt metal and cobalt oxide cores confined within nanoporous nitrogen-doped hollow carbon capsules. Core-shell structured Zn/Co-ZIF@polymer materials are fabricated through a facile coating polymer strategy on the surface of zeolitic imidazolate frameworks (ZIF). A series of hollow carbon capsules with cobalt metal and cobalt oxide are derived from a facile confined pyrolysis of Zn/Co-ZIF@polymer. The hollow Co-CoOx@N-C capsules can prevent sintering and agglomeration of the cobalt nanoparticles and the nanoporous shell allows for efficient mass transport. The specific surface area and Co particle size are optimized through finely tuning the original Zn content in ZIF particles, thus enhancing overall catalytic activity. The yolk-shell structured Zn4Co1Ox@carbon hollow capsules are shown to be a highly active and selective catalyst (selectivity >99%) for hydrogenation of nitrobenzene to aniline. Furthermore, Zn4Co1Ox@carbon hollow particles show superior catalytic stability, and no deactivation after 8 cycles of reaction. The hollow Co-CoOx@N-C capsules may shed light on a green and sustainable catalytic process for fine chemicals production.

13.
Respir Res ; 14: 129, 2013 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-24251912

RESUMO

BACKGROUND: Cardiovascular disease, osteoporosis and emphysema are associated with COPD. Associations between these factors and whether they predict all-cause mortality in COPD patients are not well understood. Therefore, we examined associations between markers of cardiovascular disease (coronary artery calcification [CAC], thoracic aortic calcification [TAC] and arterial stiffness), bone density (bone attenuation of the thoracic vertebrae), emphysema (PI-950 and 15th percentile) and all-cause mortality in a COPD cohort. METHODS: We assessed CAC, TAC, bone attenuation of the thoracic vertebrae, PI-950 and 15th percentile on low-dose chest computed tomography in COPD subjects. We measured arterial stiffness as carotid-radial pulse wave velocity (PWV), and identified deaths from the national register. RESULTS: We studied 119 COPD subjects; aged 67.8 ±7.3, 66% were males and mean FEV1% predicted was 46.0 ±17.5. Subjects were classified into three pre-specificed groups: CAC = 0 (n = 14), 0 < CAC ≤ 400 (n = 41) and CAC > 400 (n = 64). Subjects with higher CAC were more likely to be older (p < 0.001) and male (p = 0.03), and more likely to have higher systolic blood pressure (p = 0.001) and a history of hypertension (p = 0.002) or ischemic heart disease (p = 0.003). Higher CAC was associated with higher PWV (OR 1.62, p = 0.04) and lower bone attenuation (OR 0.32, p = 0.02), but not with 15th percentile, after adjustment for age, sex and pack-years of smoking. In a Cox proportional hazards model, CAC, TAC and 15th percentile predicted all-cause mortality (HR 2.01, 2.09 and 0.66, respectively). CONCLUSIONS: Increased CAC was associated with increased arterial stiffness and lower bone density in a COPD cohort. In addition, CAC, TAC and extent of emphysema predicted all-cause mortality. TRIAL REGISTRATION: Lothian NHS Board, Lothian Research Ethics Committee, LREC/2003/8/28.


Assuntos
Doenças Cardiovasculares/epidemiologia , Enfisema/epidemiologia , Osteoporose/epidemiologia , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Doença Pulmonar Obstrutiva Crônica/mortalidade , Idoso , Densidade Óssea/fisiologia , Calcinose/fisiopatologia , Doenças Cardiovasculares/fisiopatologia , Comorbidade , Estudos Transversais , Enfisema/fisiopatologia , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Osteoporose/fisiopatologia , Modelos de Riscos Proporcionais , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Taxa de Sobrevida , Rigidez Vascular/fisiologia
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