Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
1.
Chemistry ; 30(18): e202304097, 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38161190

RESUMO

Recently, several ternary phosphidotrielates and -tetrelates have been investigated with respect to their very good ionic conductivity, while less focus was pointed towards their electronic structures. Here, we report on a novel series of compounds, in which several members possess direct band gaps. We investigated the known compounds Li3AlP2, Li3GaP2, Li3InP2, and Na3InP2 and describe the synthesis and the crystal structure of novel Na3In2P3. For all mentioned phosphidotrielates reflectance UV-Vis measurements reveal direct band gaps in the visible light region with decreasing band gaps in the series: Li3AlP2 (2.45 eV), Li3GaP2 (2.18 eV), Li3InP2 (1.99 eV), Na3InP2 (1.37 eV), and Na3In2P3 (1.27 eV). All direct band gaps are confirmed by quantum chemical calculations. The unexpected property occurs despite different structure types. As a common feature all compounds contain EP4 tetrahedra, which share exclusively vertices for E=In and vertices as well as edges for E=Al and Ga. The structure of the novel Na3In2P3 is built up by a polyanionic framework of six-membered rings of corner-sharing InP4 tetrahedra. As a result, the newly designed semiconductors with direct band gaps are suitable for optoelectronic applications, and they can provide significant guidance for the design of new functional semiconductors.

2.
Adv Mater ; 35(1): e2207280, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36217842

RESUMO

Materials enabling solar energy conversion and long-term storage for readily available electrical and chemical energy are key for off-grid energy distribution. Herein, the specific confinement of a rhenium coordination complex in a metal-organic framework (MOF) unlocks a unique electron accumulating property under visible-light irradiation. About 15 C gMOF -1 of electric charges can be concentrated and stored for over four weeks without loss. Decoupled, on-demand discharge for electrochemical reactions and H2 evolution catalysis is shown and light-driven recharging can be conducted for >10 cycles with ≈90% of the initial charging capacity retained. Experimental investigations and theoretical calculations link electron trapping to MOF-induced geometry constraints as well as the coordination environment of the Re-center, highlighting the key role of MOF confinement on molecular guests. This study serves as the seminal report on 3D porous colloids achieving photoaccumulation of long-lived electrons, unlocking dark photocatalysis, and a path toward solar capacitor and solar battery systems.

3.
Adv Mater ; 35(6): e2207380, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36394175

RESUMO

Syngas, a mixture of CO and H2 , is a high-priority intermediate for producing several commodity chemicals, e.g., ammonia, methanol, and synthetic hydrocarbon fuels. Accordingly, parallel sunlight-driven catalytic conversion of CO2 and protons to syngas is a key step toward a sustainable energy cycle. State-of-the-art catalytic systems and materials often fall short as application-oriented concurrent CO and H2 evolution requires challenging reaction conditions which can hamper stability, selectivity, and efficiency. Here a light-harvesting metal-organic framework hosting two molecular catalysts is engineered to yield colloidal, water-stable, versatile nanoreactors for photocatalytic syngas generation with highly controllable product ratios. In-depth fluorescence, X-ray, and microscopic studies paired with kinetic analysis show that the host delivers energy efficiently to active sites, conceptually yielding nanozymes. This unlocked sustained CO2 reduction and H2 evolution with benchmark turnover numbers and record incident photon conversions up to 36%, showcasing a highly active and durable all-in-one material toward application in solar energy-driven syngas generation.

4.
Chem Sci ; 13(41): 12164-12174, 2022 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-36349115

RESUMO

Optimising catalyst materials for visible light-driven fuel production requires understanding complex and intertwined processes including light absorption and catalyst stability, as well as mass, charge, and energy transport. These phenomena can be uniquely combined (and ideally controlled) in porous host-guest systems. Towards this goal we designed model systems consisting of molecular complexes as catalysts and porphyrin metal-organic frameworks (MOFs) as light-harvesting and hosting porous matrices. Two MOF-rhenium molecule hybrids with identical building units but differing topologies (PCN-222 and PCN-224) were prepared including photosensitiser-catalyst dyad-like systems integrated via self-assembled molecular recognition. This allowed us to investigate the impact of MOF topology on solar fuel production, with PCN-222 assemblies yielding a 9-fold turnover number enhancement for solar CO2-to-CO reduction over PCN-224 hybrids as well as a 10-fold increase compared to the homogeneous catalyst-porphyrin dyad. Catalytic, spectroscopic and computational investigations identified larger pores and efficient exciton hopping as performance boosters, and further unveiled a MOF-specific, wavelength-dependent catalytic behaviour. Accordingly, CO2 reduction product selectivity is governed by selective activation of two independent, circumscribed or delocalised, energy/electron transfer channels from the porphyrin excited state to either formate-producing MOF nodes or the CO-producing molecular catalysts.

5.
Br J Pharmacol ; 179(14): 3645-3650, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35481868

RESUMO

Commonly employed methods for reducing unwanted variation in pharmacology studies, such as data normalisation to baseline or control values, are suboptimal and potentially detrimental. This article highlights the value of using a technique called analysis of covariance (ANCOVA) to incorporate supplementary measurements in the analysis to improve the precision of the treatment comparisons and reduce the required sample size. This technique is not new, but unfortunately, it has been under-utilised in the statistical analysis of pharmacological data. ANCOVA is an extension of the methods of analysis of variance (ANOVA) and simply requires that we take additional measurements that are statistically related to the response measurements but which are themselves unaffected by the treatments being studied. Most often, in pharmacological studies, these additional measurements would be the baseline or pre-dose reading corresponding to the response measurement. As many pharmacologists routinely make use of baseline readings in their analysis through normalisation, this article describes a more appropriate method to account for the variation in the baseline readings.


Assuntos
Modelos Estatísticos , Projetos de Pesquisa , Análise de Variância , Animais
6.
Angew Chem Int Ed Engl ; 61(8): e202115100, 2022 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-34825766

RESUMO

Vectorial catalysis-controlling multi-step reactions in a programmed sequence and by defined spatial localization in a microscale device-is an enticing goal in bio-inspired catalysis research. However, translating concepts from natural cascade biocatalysis into artificial hierarchical chemical systems remains a challenge. Herein, we demonstrate integration of two different surface-anchored nanometer-sized metal-organic frameworks (MOFs) in a microfluidic device for modelling vectorial catalysis. Catalyst immobilization at defined sections along the microchannel and a two-step cascade reaction was conducted with full conversion after 30 seconds and high turnover frequencies (TOF≈105  h-1 ).

8.
Am J Ophthalmol Case Rep ; 23: 101181, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34401602

RESUMO

PURPOSE: To report a case of retained anterior chamber graphite foreign body with subsequent inflammation 20 years later. OBSERVATIONS: A 29-year-old female who presented with first episode of acute blurring of vision and eye redness was noted to have a retained intraocular graphite foreign body in her anterior chamber. She recalled being accidently hit by a mechanical pencil 20 years ago. CONCLUSIONS AND IMPORTANCE: Retained intraocular graphite foreign bodies are inert and generally do not cause inflammation. This is the longest reported duration of retained anterior chamber graphite foreign body that developed subsequent inflammation and corneal endothelial damage only 20 years later.

9.
Faraday Discuss ; 231(0): 281-297, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34240093

RESUMO

Artificial photosystems assembled from molecular complexes, such as the photocatalyst fac-ReBr(CO)3(4,4'-dcbpy) (dcbpy = dicarboxy-2,2'-bipyridine) and the photosensitiser Ru(bpy)2(5,5'-dcbpy)Cl2 (bpy = 2,2'-bipyridine), are a wide-spread approach for solar fuel production. Recently metal-organic framework (MOF) entrapping of such complexes was demonstrated as a promising concept for catalyst stabilisation and reaction environment optimisation in colloidal-based CO2 reduction. Building on this strategy, here we examined the influence of MIL-101-NH2(Al) MOF particle size, the electron donor source, and the presence of an organic base on the photocatalytic CO2-to-CO reduction performance, and the differences to homogeneous systems. A linear relation between smaller scaffold particle size and higher photocatalytic activity, longer system lifetimes for benign electron donors, and increased turnover numbers (TONs) with certain additive organic bases, were determined. This enabled understanding of key molecular catalysis phenomena and synergies in the nanoreactor-like host-guest assembly, and yielded TONs of ∼4300 over 96 h of photocatalysis under optimised conditions, surpassing homogeneous TON values and lifetimes.


Assuntos
Estruturas Metalorgânicas , Catálise , Compostos Orgânicos , Oxirredução , Fármacos Fotossensibilizantes
10.
J Trauma Acute Care Surg ; 91(3): 566-570, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34137741

RESUMO

BACKGROUND: When head injured children undergo head computed tomography (CT), radiation dosing can vary considerably between institutions, potentially exposing children to excess radiation, increasing risk for malignancies later in life. We compared radiation delivery from head CTs at a level 1 pediatric trauma center (PTC) versus scans performed at referring adult general hospitals (AGHs). We hypothesized that children at our PTC receive a significantly lower radiation dose than children who underwent CT at AGHs for similar injury profiles. METHODS: We retrospectively reviewed the charts of all patients younger than 18 years who underwent CT for head injury at our PTC or at an AGH before transfer between January 1 and December 31, 2019. We analyzed demographic and clinical data. Our primary outcome was head CT radiation dose, as calculated by volumetric CT dose index (CTDIvol) and dose-length product (DLP; the product of CTDIvol and scan length). We used unadjusted bivariate and multivariable linear regression (adjusting for age, weight, sex) to compare doses between Children's Hospital Los Angeles and AGHs. RESULTS: Of 429 scans reviewed, 193 were performed at our PTC, while 236 were performed at AGHs. Mean radiation dose administered was significantly lower at our PTC compared with AGHs (CTDIvol 20.3/DLP 408.7 vs. CTDIvol 30.6/DLP 533, p < 0.0001). This was true whether the AGH was a trauma center or not. After adjusting for covariates, findings were similar for both CTDIvol and DLP. Patients who underwent initial CT at an AGH and then underwent a second CT at our PTC received less radiation for the second CT (CTDIvol 25.6 vs. 36.5, p < 0.0001). CONCLUSIONS: Head-injured children consistently receive a lower radiation dose when undergoing initial head CT at a PTC compared with AGHs. This provides a basis for programs aimed at establishing protocols to deliver only as much radiation as necessary to children undergoing head CT. LEVEL OF EVIDENCE: Care Management/Therapeutic, level IV.


Assuntos
Cabeça/diagnóstico por imagem , Doses de Radiação , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Adolescente , Fatores Etários , Criança , Pré-Escolar , Feminino , Hospitais Gerais , Hospitais Pediátricos , Humanos , Lactente , Modelos Lineares , Los Angeles , Masculino , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , Centros de Traumatologia
11.
Case Rep Ophthalmol ; 12(1): 214-218, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33976685

RESUMO

PURPOSE: To report a case of recalcitrant pseudomonas keratitis with a rare presentation of hyphaema. OBSERVATION: A 45-year-old female was noted to have contact lens-related pseudomonas keratitis with hyphaema. The organism was refractory to multiple antibiotics and only responded to Tazocin eye drops. CONCLUSION AND IMPORTANCE: Hyphaema is a rare presentation in bacterial keratitis and could represent infection with an especially virulent organism. Use of Aspirin could precipitate hyphaema in infective keratitis. Alternative antibiotic choices such as Tazocin, colistin, meropenem, and imipenem can be considered when standard therapy is ineffective for multidrug-resistant Pseudomonas keratitis.

12.
Angew Chem Int Ed Engl ; 60(33): 17854-17860, 2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34014024

RESUMO

A strategy to improve homogeneous molecular catalyst stability, efficiency, and selectivity is the immobilization on supporting surfaces or within host matrices. Herein, we examine the co-immobilization of a CO2 reduction catalyst [ReBr(CO)3 (4,4'-dcbpy)] and a photosensitizer [Ru(bpy)2 (5,5'-dcbpy)]Cl2 using the isoreticular series of metal-organic frameworks (MOFs) UiO-66, -67, and -68. Specific host pore size choice enables distinct catalyst and photosensitizer spatial location-either at the outer MOF particle surface or inside the MOF cavities-affecting catalyst stability, electronic communication between reaction center and photosensitizer, and consequently the apparent catalytic rates. These results allow for a rational understanding of an optimized supramolecular layout of catalyst, photosensitizer, and host matrix.

13.
Biotechnol Adv ; 45: 107639, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33002583

RESUMO

While DNA's perpetual role in biology and life science is well documented, its burgeoning digital applications are beginning to garner significant interest. As the development of novel technologies requires continuous research, product development, startup creation, and financing, this work provides an overview of each respective area and highlights current trends, challenges, and opportunities. These are supported by numerous interviews with key opinion leaders from across academia, government agencies and the commercial sector, as well as investment data analysis. Our findings illustrate the societal and economic need for technological innovation and disruption in data storage, paving the way for nature's own time-tested, advantageous, and unrivaled solution. We anticipate a significant increase in available investment capital and continuous scientific progress, creating a ripe environment on which DNA data storage-enabling startups can capitalize to bring DNA data storage into daily life.


Assuntos
Armazenamento e Recuperação da Informação , Investimentos em Saúde , DNA/genética
14.
Am J Ophthalmol Case Rep ; 20: 100939, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33083632

RESUMO

PURPOSE: The finding of an anterior chamber cilium after small incision cataract surgery is rare, with only five prior cases being found on literature review. Strategies include observation if there is no evidence of inflammation or infection and prompt removal if the situation changes.1-5 This case adds to the number of case reports and highlights that unexpected findings such as this can be seen on the first postoperative day exam and the clinical decisions made to remove it promptly. OBSERVATIONS: A 69 year-old woman had uncomplicated phacoemulsification cataract extraction with posterior chamber intraocular lens implantation in the right eye using a superonasal corneal incision and inferotemporal paracentesis. Examination at 1 day noted a cilium in the anterior chamber. The cilium was removed the same day without complications. CONCLUSIONS AND IMPORTANCE: This case report shows that intraocular cilia can occasionally be seen following routine small incision sutureless cataract surgery even when there is no evidence of it immediately following surgery.

15.
J Perianesth Nurs ; 35(4): 403-406, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32178950

RESUMO

PURPOSE: To determine if lavender aromatherapy can reduce preoperative anxiety in cataract surgery patients. DESIGN: Single-center prospective randomized placebo-controlled trial. METHODS: Seventy-five patients awaiting cataract surgery were randomized to lavender essential oil or grape seed oil (control) and administered the State-Trait Anxiety Inventory. Vital signs were also recorded. FINDINGS: Patients in the lavender group showed greater improvements in self-reported anxiety using the State-Trait Anxiety Inventory (P = .023, two-sample t test). Compared with the control group, the effects of lavender on the reduction of anxiety were statistically significant when adjusting for age, gender, and baseline scores (P = .012, analysis of covariance). CONCLUSIONS: Lavender aromatherapy reduced anxiety in preoperative cataract surgery patients.


Assuntos
Ansiedade/terapia , Aromaterapia , Catarata , Lavandula , Ansiedade/prevenção & controle , Catarata/psicologia , Humanos , Estudos Prospectivos
17.
J Infect ; 75(1): 20-25, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28435086

RESUMO

OBJECTIVES: To establish risk factors for Clostridium difficile colonization among hospitalized patients in England. METHODS: Patients admitted to elderly medicine wards at three acute hospitals in England were recruited to a prospective observational study. Participants were asked to provide a stool sample as soon as possible after enrolment and then weekly during their hospital stay. Samples were cultured for C. difficile before ribotyping and toxin detection by PCR. A multivariable logistic regression model of risk factors for C. difficile colonization was fitted from univariable risk factors significant at the p < 0.05 level. RESULTS: 410/727 participants submitted ≥1 stool sample and 40 (9.8%) carried toxigenic C. difficile in the first sample taken. Ribotype 106 was identified three times and seven other ribotypes twice. No ribotype 027 strains were identified. Independent predictors of colonization were previous C. difficile infection (OR 4.53 (95% C.I. 1.33-15.48) and malnutrition (MUST score ≥2) (OR 3.29 (95% C.I. 1.47-7.35)). Although C. difficile colonised patients experienced higher 90-day mortality, colonization was not an independent risk for death. CONCLUSIONS: In a non-epidemic setting patients who have previously had CDI and have a MUST score of ≥2 are at increased risk of C. difficile colonization and could be targeted for active surveillance to prevent C. difficile transmission.


Assuntos
Toxinas Bacterianas/biossíntese , Clostridioides difficile/isolamento & purificação , Infecções por Clostridium/epidemiologia , Infecção Hospitalar/epidemiologia , Enterotoxinas/biossíntese , Hospitalização , Idoso de 80 Anos ou mais , Antibacterianos/uso terapêutico , Clostridioides difficile/classificação , Clostridioides difficile/efeitos dos fármacos , Clostridioides difficile/genética , Infecções por Clostridium/tratamento farmacológico , Infecções por Clostridium/microbiologia , Infecções por Clostridium/mortalidade , Infecção Hospitalar/microbiologia , Diarreia/epidemiologia , Inglaterra/epidemiologia , Fezes/microbiologia , Feminino , Humanos , Modelos Logísticos , Masculino , Reação em Cadeia da Polimerase , Estudos Prospectivos , Ribotipagem , Fatores de Risco
18.
Sci Transl Med ; 8(335): 335ra56, 2016 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-27099175

RESUMO

In common with other chronic pain conditions, there is an unmet clinical need in the treatment of inherited erythromelalgia (IEM). TheSCN9Agene encoding the sodium channel Nav1.7 expressed in the peripheral nervous system plays a critical role in IEM. A gain-of-function mutation in this sodium channel leads to aberrant sensory neuronal activity and extreme pain, particularly in response to heat. Five patients with IEM were treated with a new potent and selective compound that blocked the Nav1.7 sodium channel resulting in a decrease in heat-induced pain in most of the patients. We derived induced pluripotent stem cell (iPSC) lines from four of five subjects and produced sensory neurons that emulated the clinical phenotype of hyperexcitability and aberrant responses to heat stimuli. When we compared the severity of the clinical phenotype with the hyperexcitability of the iPSC-derived sensory neurons, we saw a trend toward a correlation for individual mutations. The in vitro IEM phenotype was sensitive to Nav1.7 blockers, including the clinical test agent. Given the importance of peripherally expressed sodium channels in many pain conditions, our approach may have broader utility for a wide range of pain and sensory conditions.


Assuntos
Eritromelalgia/tratamento farmacológico , Células-Tronco Pluripotentes Induzidas/citologia , Dor/tratamento farmacológico , Dor/metabolismo , Éteres Fenílicos/uso terapêutico , Células Receptoras Sensoriais/efeitos dos fármacos , Células Receptoras Sensoriais/metabolismo , Sulfonamidas/uso terapêutico , Adulto , Eritromelalgia/genética , Feminino , Humanos , Masculino , Mutação/genética , Canal de Sódio Disparado por Voltagem NAV1.7/metabolismo , Células Receptoras Sensoriais/citologia
19.
Int J Pediatr Otorhinolaryngol ; 79(6): 883-887, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25887132

RESUMO

OBJECTIVES: Lymphatic malformations are congenital vascular anomalies that occur from abnormal development of the lymphatic channels. Studies have shown that sclerotherapy can be a reliable alternative to surgery. The purpose of this retrospective study is to evaluate the safety and efficacy of percutaneous sclerotherapy with doxycycline and 3% Sotradecol as primary treatment for pediatric head and neck LMs, and to assess outcomes based on lesion classification, location and sclerosant used. STUDY DESIGN: This study was a single center, retrospective, case series study. MATERIALS AND METHODS: The medical records of 38 children who underwent percutaneous sclerotherapy of LMs in the head and neck region at our tertiary care center between 1/1/2006 and 1/31/2011 were reviewed. A mean average of 2.9 (range 1-10) sclerotherapy sessions per child were performed. LMs involved primarily the face (61.3%), posterior neck (48.4%), submental area (45.2%), and anterior neck (35.5%). RESULTS: Twenty-nine subjects had adequate follow-up data, with 51.7% demonstrating complete resolution, 27.6% moderate improvement, and 20.7% no response. There was no significant difference in the outcome based on the sclerosant agent used or location of the lesion. Lesion type did affect outcome and macrocystic lesions were found to have a significantly higher resolution rate (95.2%) than microcystic or mixed lesions (p < 0.05). The total number of complications was similar between agents and all were minor. CONCLUSION: Our results indicate that percutaneous therapy with doxycycline and Sotradecol is safe and effective for children with LMs of the head and neck. Better outcomes were observed with macrocystic LMs. LEVEL OF EVIDENCE: 4.


Assuntos
Antibacterianos/uso terapêutico , Doxiciclina/uso terapêutico , Anormalidades Linfáticas/terapia , Soluções Esclerosantes/uso terapêutico , Escleroterapia , Tetradecilsulfato de Sódio/uso terapêutico , Adolescente , Criança , Pré-Escolar , Face , Feminino , Humanos , Lactente , Anormalidades Linfáticas/patologia , Masculino , Pescoço , Estudos Retrospectivos , Escleroterapia/métodos , Resultado do Tratamento
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...