Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 123
Filtrar
Más filtros

Bases de datos
Tipo del documento
Intervalo de año de publicación
1.
J Am Chem Soc ; 146(25): 16977-16981, 2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38874381

RESUMEN

In metal-organic frameworks (MOFs) the interplay between the dynamics of individual components and how these are constrained by the extended lattice can yield unusual emergent phenomena. For the archetypal Zr-MOF, UiO-66, we explore the cooperative dynamics of a Zr-node transformation that gives rise to negative thermal expansion (NTE). Using in situ synchrotron X-ray scattering, with powder diffraction and pair distribution function (PDF) analyses, we identify lattice hysteresis and a thermal ramp-rate-dependence of the thermal expansion. Specifically, kinetic trapping of distorted node states formed at high temperature, leads to broad variability in the apparent thermal expansion which ranges from large positive to large negative thermal expansion with coefficients of thermal expansion (CTE) from +45 to -80 × 10-6K-1. Time-resolved relaxation studies at selected temperatures suggest that when equilibrated UiO-66 is intrinsically NTE, with a CTE of -35 × 10-6K-1. Kinetic trapping of the node-distorted state following high temperature activation has broad implications for characterization and applications of these Zr-MOFs; the nonequilibrium node state depends on the thermal history of the sample with quench vs slow cooling likely to impact gas binding, pore volume, and accessible catalytic sites.

2.
J Am Chem Soc ; 146(10): 6557-6565, 2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38271670

RESUMEN

Despite global efforts to reduce carbon dioxide (CO2) emissions, continued industrialization threatens to exacerbate climate change. This work investigates methods to capture CO2, with a focus on the SIFSIX-3-Ni metal-organic framework (MOF) as a direct air capture (DAC) sorbent. SIFSIX-3-Ni exhibits promising CO2 adsorption properties but suffers from degradation processes under accelerated aging, which are akin to column regeneration conditions. Herein, we have grown the largest SIFSIX-3-Ni single crystals to date, facilitating single crystal X-ray diffraction analyses that enabled direct observation of the H2O and CO2 dynamics through adsorption and desorption. In addition, a novel space group (I4/mcm) for the SIFSIX-3-Ni is identified, which provided insights into structural transitions within the framework and elucidated water's role in degrading CO2 uptake performance as the material ages. In situ X-ray scattering methods revealed long-range and local structural transformations associated with CO2 adsorption in the framework pores as well as a temperature-dependent desorption mechanism. Pair distribution function analysis revealed a partial decomposition to form nonporous single-layer nanosheets of edge-sharing nickel oxide octahedra upon aging. The formation of these nanosheets is irreversible and reduces the amount of active material for the CO2 sorption. These findings provide crucial insights for the development of efficient and stable DAC sorbents, effectively reducing greenhouse gases, and suggest avenues for enhancing MOF stability under practical DAC conditions.

3.
Chemistry ; : e202401339, 2024 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-38872486

RESUMEN

Sustainable alternatives for the energy intensive synthesis of H2O2 are necessary. Molecular cobalt catalysts show potential but are typically restricted by undesired bimolecular pathways leading to the breakdown of both H2O2 and the catalyst. The confinement of cobalt porphyrins in the PCN-224 metal-organic framework leads to an enhanced selectivity towards H2O2 and stability of the catalyst. Consequently, oxygen can now be selectively reduced to hydrogen peroxide with a stable conversion for at least 5 h, illustrating the potential of catalysts confined in MOFs to increase the selectivity and stability of electrocatalytic conversions.

4.
Br J Anaesth ; 132(1): 66-75, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37953199

RESUMEN

BACKGROUND: Preoperative fasting reduces the risk of pulmonary aspiration during anaesthesia, and 2-h fasting for clear fluids has commonly been recommended. Based on recent evidence of shorter fasting times being safe, the Swiss Society of Paediatric Anaesthesia began recommending 1-h fasting for clear fluids in 2018. This prospective, observational, multi-institutional cohort study aimed to investigate the incidence of adverse respiratory events after implementing the new national recommendation. METHODS: Eleven Swiss anaesthesia institutions joined this cohort study and included patients aged 0-15 yr undergoing anaesthesia for elective procedures after implementation of the 1-h fasting instruction. The primary outcome was the perioperative (defined as the time from anaesthesia induction to emergence) incidence of pulmonary aspiration, gastric regurgitation, and vomiting. Data are presented as median (inter-quartile range; minimum-maximum) or count (percentage). RESULTS: From June 2019 to July 2021, 22 766 anaesthetics were recorded with pulmonary aspiration occurring in 25 (0.11%), gastric regurgitation in 34 (0.15%), and vomiting in 85 (0.37%) cases. No major morbidity or mortality was associated with pulmonary aspiration. Subgroup analysis by effective fasting times (<2 h [n=7306] vs ≥2 h [n=14 660]) showed no significant difference for pulmonary aspiration between these two groups (9 [0.12%] vs 16 [0.11%], P=0.678). Median effective fasting time for clear fluids was 157 [104-314; 2-2385] min. CONCLUSIONS: Implementing a national recommendation of 1-h clear fluid fasting was not associated with a higher incidence of pulmonary aspiration compared with previously reported data.


Asunto(s)
Reflujo Laringofaríngeo , Neumonía por Aspiración , Niño , Humanos , Incidencia , Estudios de Cohortes , Estudios Prospectivos , Ayuno , Cuidados Preoperatorios/métodos , Aspiración Respiratoria , Vómitos
5.
J Adolesc ; 96(4): 720-731, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38235977

RESUMEN

INTRODUCTION: The effort adolescents make determines the risk for dropping out of vocational education and training (VET) early and their chances of graduating upper secondary education. Studies have shown that adolescents' efforts decrease during the transition to upper secondary general education and increases for the transition to VET. In this study, we examined adolescent self-efficacy in lower secondary education, adolescent-instructor relationship (AIR) in VET and general education, and perceived person-environment fit (PEF) as predictors of adolescent effort. METHOD: We calculated two longitudinal multigroup structural equation models. Group 1 comprised 1266 (mean age in T1 = 15.7 years; female: 44%) lower secondary education graduates who moved on to VET with two learning contexts, company and vocational school in Switzerland. Group 2 included 517 (mean age in T1 = 15.7 years; female: 44%) lower secondary education graduates who moved on to upper secondary general education and thus stayed in a school. Adolescents' survey data was collected in 2016 and 2017. RESULTS: Self-efficacy in lower secondary education and AIR in upper secondary education indirectly predicted effort in upper secondary education via PEF, controlling for effort in lower secondary education. Findings were similar for general education and vocational school. However, the effects differed between company and general education (moderation). The positive effect of AIR on PEF was statistically significantly weaker for adolescents in general education than for adolescents in VET and their company learning context. CONCLUSION: We discuss strategies to enhance adolescents' efforts in upper secondary education.


Asunto(s)
Autoeficacia , Educación Vocacional , Humanos , Femenino , Adolescente , Masculino , Suiza , Estudios Longitudinales , Encuestas y Cuestionarios , Instituciones Académicas , Abandono Escolar/estadística & datos numéricos , Abandono Escolar/psicología
6.
Angew Chem Int Ed Engl ; : e202408443, 2024 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-38976771

RESUMEN

We incorporate Se into the 3D halide perovskite framework using the zwitterionic ligand: SeCYS (+NH3(CH2)2Se-), which occupies both the X- and A+ sites in the prototypical ABX3 perovskite. The new organoselenide-halide perovskites: (SeCYS)PbX2 (X = Cl, Br) expand upon the recently discovered organosulfide-halide perovskites. Single-crystal X-ray diffraction and pair distribution function analysis reveal the average structures of the organoselenide-halide perovskites, whereas the local lead coordination environments and their distributions were probed through solid-state 77Se and 207Pb NMR, complemented by theoretical simulations. Density functional theory calculations illustrate that the band structures of (SeCYS)PbX2 largely resemble those of their S analogs, with similar band dispersion patterns, yet with a considerable bandgap decrease. Optical absorbance measurements indeed show bandgaps of 2.07 and 1.86 eV for (SeCYS)PbX2 with X = Cl and Br, respectively. We further demonstrate routes to alloying the halides (Cl, Br) and chalcogenides (S, Se) continuously tuning the bandgap from 1.86 to 2.31 eV-straddling the ideal range for tandem solar cells or visible-light photocatalysis. The comprehensive description of the average and local structures, and how they can fine-tune the bandgap and potential trap states, respectively, establishes the foundation for understanding this new perovskite family, which combines solid-state and organo-main-group chemistry.

7.
Small ; 19(14): e2205412, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36653934

RESUMEN

The novel material class of high entropy oxides with their unique and unexpected physicochemical properties is a candidate for energy applications. Herein, it is reported for the first time about the physico- and (photo-) electrochemical properties of ordered mesoporous (CoNiCuZnMg)Fe2 O4 thin films synthesized by a soft-templating and dip-coating approach. The A-site high entropy ferrites (HEF) are composed of periodically ordered mesopores building a highly accessible inorganic nanoarchitecture with large specific surface areas. The mesoporous spinel HEF thin films are found to be phase-pure and crack-free on the meso- and macroscale. The formation of the spinel structure hosting six distinct cations is verified by X-ray-based characterization techniques. Photoelectron spectroscopy gives insight into the chemical state of the implemented transition metals supporting the structural characterization data. Applied as photoanode for photoelectrochemical water splitting, the HEFs are photostable over several hours but show only low photoconductivity owing to fast surface recombination, as evidenced by intensity-modulated photocurrent spectroscopy. When applied as oxygen evolution reaction electrocatalyst, the HEF thin films possess overpotentials of 420 mV at 10 mA cm-2 in 1 m KOH. The results imply that the increase of the compositional disorder enhances the electronic transport properties, which are beneficial for both energy applications.

8.
Chemistry ; 29(24): e202300277, 2023 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-36823437

RESUMEN

Metal oxide-based photoelectrodes for solar water splitting often utilize nanostructures to increase the solid-liquid interface area. This reduces charge transport distances and increases the photocurrent for materials with short minority charge carrier diffusion lengths. While the merits of nanostructuring are well established, the effect of surface order on the photocurrent and carrier recombination has not yet received much attention in the literature. To evaluate the impact of pore ordering on the photoelectrochemical properties, mesoporous CuFe2 O4 (CFO) thin film photoanodes were prepared by dip-coating and soft-templating. Here, the pore order and geometry can be controlled by addition of copolymer surfactants poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic® F-127), polyisobutylene-block-poly(ethylene oxide) (PIB-PEO) and poly(ethylene-co-butylene)-block-poly(ethylene oxide) (Kraton liquid™-PEO, KLE). The non-ordered CFO showed the highest photocurrent density of 0.2 mA/cm2 at 1.3 V vs. RHE for sulfite oxidation, but the least photocurrent density for water oxidation. Conversely, the ordered CFO presented the best photoelectrochemical water oxidation performance. These differences can be understood on the basis of the high surface area, which promotes hole transfer to sulfite (a fast hole acceptor), but retards oxidation of water (a slow hole acceptor) due to electron-hole recombination at the defective surface. This interpretation is confirmed by intensity-modulated photocurrent (IMPS) and vibrating Kelvin probe surface photovoltage spectroscopy (VKP-SPS). The lowest surface recombination rate was observed for the ordered KLE-based mesoporous CFO, which retains spherical pore shapes at the surface resulting in fewer surface defects. Overall, this work shows that the photoelectrochemical energy conversion efficiency of copper ferrite thin films is not just controlled by the surface area, but also by surface order.

9.
J Clin Apher ; 38(2): 77-278, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37017433

RESUMEN

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. In the Ninth Edition, the JCA Special Issue Writing Committee has incorporated systematic review and evidence-based approaches in the grading of evidence and categorization of apheresis indications to make recommendations on the use of apheresis in a wide variety of diseases and conditions. This edition has largely maintained the general layout and concept of a fact sheet introduced in the Fourth Edition (2007). Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease or medical condition. The Ninth Edition of the JCA Special Issue comprises 91 fact sheets and 166 graded and categorized indications. This includes seven new fact sheets, nine new indications on existing fact sheets, and eight changes in the category for existing indications. The Ninth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.


Asunto(s)
Eliminación de Componentes Sanguíneos , Medicina Basada en la Evidencia , Humanos , Estados Unidos , Escritura
10.
Angew Chem Int Ed Engl ; 62(12): e202218039, 2023 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-36656994

RESUMEN

The chemical selectivity and faradaic efficiency of high-index Cu facets for the CO2 reduction reaction (CO2 RR) is investigated. More specifically, shape-controlled nanoparticles enclosed by Cu {hk0} facets are fabricated using Cu multilayer deposition at three distinct layer thicknesses on the surface facets of Au truncated ditetragonal nanoprisms (Au DTPs). Au DTPs are shapes enclosed by 12 high-index {310} facets. Facet angle analysis confirms DTP geometry. Elemental mapping analysis shows Cu surface layers are uniformly distributed on the Au {310} facets of the DTPs. The 7 nm Au@Cu DTPs high-index {hk0} facets exhibit a CH4 : CO product ratio of almost 10 : 1 compared to a 1 : 1 ratio for the reference 7 nm Au@Cu nanoparticles (NPs). Operando Fourier transform infrared spectroscopy spectra disclose reactive adsorbed *CO as the main intermediate, whereas CO stripping experiments reveal the high-index facets enhance the *CO formation followed by rapid desorption or hydrogenation.

11.
Small ; 18(42): e2204116, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36114151

RESUMEN

The electrochemical nitrogen reduction reaction (NRR) to ammonia (NH3 ) is a potentially carbon-neutral and decentralized supplement to the established Haber-Bosch process. Catalytic activation of the highly stable dinitrogen molecules remains a great challenge. Especially metal-free nitrogen-doped carbon catalysts do not often reach the desired selectivity and ammonia production rates due to their low concentration of NRR active sites and possible instability of heteroatoms under electrochemical potential, which can even contribute to false positive results. In this context, the electrochemical activation of nitrogen-doped carbon electrocatalysts is an attractive, but not yet established method to create NRR catalytic sites. Herein, a metal-free C2 N material (HAT-700) is electrochemically etched prior to application in NRR to form active edge-sites originating from the removal of terminal nitrile groups. Resulting activated metal-free HAT-700-A shows remarkable catalytic activity in electrochemical nitrogen fixation with a maximum Faradaic efficiency of 11.4% and NH3 yield of 5.86 µg mg-1 cat h-1 . Experimental results and theoretical calculations are combined, and it is proposed that carbon radicals formed during activation together with adjacent pyridinic nitrogen atoms play a crucial role in nitrogen adsorption and activation. The results demonstrate the possibility to create catalytically active sites on purpose by etching labile functional groups prior to NRR.


Asunto(s)
Carbono , Fijación del Nitrógeno , Carbono/química , Amoníaco , Dominio Catalítico , Nitrógeno/química , Metales , Nitrilos
12.
PLoS Comput Biol ; 17(8): e1008904, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34339413

RESUMEN

The killer-cell immunoglobulin-like receptor (KIR) complex on chromosome 19 encodes receptors that modulate the activity of natural killer cells, and variation in these genes has been linked to infectious and autoimmune disease, as well as having bearing on pregnancy and transplant outcomes. The medical relevance and high variability of KIR genes makes short-read sequencing an attractive technology for interrogating the region, providing a high-throughput, high-fidelity sequencing method that is cost-effective. However, because this gene complex is characterized by extensive nucleotide polymorphism, structural variation including gene fusions and deletions, and a high level of homology between genes, its interrogation at high resolution has been thwarted by bioinformatic challenges, with most studies limited to examining presence or absence of specific genes. Here, we present the PING (Pushing Immunogenetics to the Next Generation) pipeline, which incorporates empirical data, novel alignment strategies and a custom alignment processing workflow to enable high-throughput KIR sequence analysis from short-read data. PING provides KIR gene copy number classification functionality for all KIR genes through use of a comprehensive alignment reference. The gene copy number determined per individual enables an innovative genotype determination workflow using genotype-matched references. Together, these methods address the challenges imposed by the structural complexity and overall homology of the KIR complex. To determine copy number and genotype determination accuracy, we applied PING to European and African validation cohorts and a synthetic dataset. PING demonstrated exceptional copy number determination performance across all datasets and robust genotype determination performance. Finally, an investigation into discordant genotypes for the synthetic dataset provides insight into misaligned reads, advancing our understanding in interpretation of short-read sequencing data in complex genomic regions. PING promises to support a new era of studies of KIR polymorphism, delivering high-resolution KIR genotypes that are highly accurate, enabling high-quality, high-throughput KIR genotyping for disease and population studies.


Asunto(s)
Inmunogenética/estadística & datos numéricos , Receptores KIR/genética , África Austral , Alelos , Biología Computacional , Simulación por Computador , Bases de Datos de Ácidos Nucleicos/estadística & datos numéricos , Europa (Continente) , Dosificación de Gen , Genética de Población/estadística & datos numéricos , Genotipo , Secuenciación de Nucleótidos de Alto Rendimiento/estadística & datos numéricos , Humanos , Polimorfismo Genético , Receptores KIR/clasificación , Alineación de Secuencia/estadística & datos numéricos , Diseño de Software
13.
Eur J Anaesthesiol ; 39(1): 4-25, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34857683

RESUMEN

Current paediatric anaesthetic fasting guidelines have recommended conservative fasting regimes for many years and have not altered much in the last decades. Recent publications have employed more liberal fasting regimes with no evidence of increased aspiration or regurgitation rates. In this first solely paediatric European Society of Anaesthesiology and Intensive Care (ESAIC) pre-operative fasting guideline, we aim to present aggregated and evidence-based summary recommendations to assist clinicians, healthcare providers, patients and parents. We identified six main topics for the literature search: studies comparing liberal with conservative regimens; impact of food composition; impact of comorbidity; the use of gastric ultrasound as a clinical tool; validation of gastric ultrasound for gastric content and gastric emptying studies; and early postoperative feeding. The literature search was performed by a professional librarian in collaboration with the ESAIC task force. Recommendations for reducing clear fluid fasting to 1 h, reducing breast milk fasting to 3 h, and allowing early postoperative feeding were the main results, with GRADE 1C or 1B evidence. The available evidence suggests that gastric ultrasound may be useful for clinical decision-making, and that allowing a 'light breakfast' may be well tolerated if the intake is well controlled. More research is needed in these areas as well as evaluation of how specific patient or treatment-related factors influence gastric emptying.


Asunto(s)
Anestesiología , Ayuno , Niño , Cuidados Críticos , Femenino , Vaciamiento Gástrico , Humanos , Cuidados Preoperatorios , Ultrasonografía
14.
Small ; 17(18): e2007702, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33738928

RESUMEN

Studying model nanoparticles is one approach to better understand the structural evolution of a catalyst during reactions. These nanoparticles feature well-defined faceting, offering the possibility to extract structural information as a function of facet orientation and compare it to theoretical simulations. Using Bragg Coherent X-ray Diffraction Imaging, the uniformity of electrochemically synthesized model catalysts is studied, here high-index faceted tetrahexahedral (THH) platinum nanoparticles at ambient conditions. 3D images of an individual nanoparticle are obtained, assessing not only its shape but also the specific components of the displacement and strain fields both at the surface of the nanocrystal and inside. The study reveals structural diversity of shapes and defects, and shows that the THH platinum nanoparticles present strain build-up close to facets and edges. A facet recognition algorithm is further applied to the imaged nanoparticles and provides facet-dependent structural information for all measured nanoparticles. In the context of strain engineering for model catalysts, this study provides insight into the shape-controlled synthesis of platinum nanoparticles with high-index facets.

15.
J Clin Apher ; 36(6): 878-881, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34510542

RESUMEN

Since vaccination for SARS-CoV-2 coronavirus started, the trajectory of patient numbers infected with the virus has improved once; however, variants of SARS-CoV-2 have emerged and more people have been infected; therefore, pandemic status is still far from resolution. Government and social efforts to prevent coronavirus infection continue in most states in the US and globally even after the Centers for Disease Control and Prevention declared some restriction relief for fully vaccinated people in March 2021. Healthcare institutions and various professional organizations have developed guidelines or policies to prevent the spread of these coronaviruses in the setting of apheresis. In this report, the issues that apheresis services may encounter under the current COVID-19 (SARS-CoV-2 coronavirus disease) pandemic will be discussed with potential strategies that can be adapted for efficient and optimum use of apheresis resources.


Asunto(s)
Eliminación de Componentes Sanguíneos , COVID-19/epidemiología , Pandemias , Eliminación de Componentes Sanguíneos/métodos , Eliminación de Componentes Sanguíneos/estadística & datos numéricos , Humanos , Guías de Práctica Clínica como Asunto , SARS-CoV-2 , Sociedades Médicas , Estados Unidos/epidemiología
16.
Angew Chem Int Ed Engl ; 60(11): 5898-5906, 2021 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-33497000

RESUMEN

A new strategy affords "non-nano" carbon materials as dehydrogenation catalysts that perform similarly to nanocarbons. Polymer-based carbon precursors that combine a soft-template approach with ion adsorption and catalytic graphitization are key to this synthesis strategy, thus offering control over macroscopic shape, texture, and crystallinity and resulting in a hybrid amorphous/graphitic carbon after pyrolysis. From this intermediate the active carbon catalyst is prepared by removing the amorphous parts of the hybrid carbon materials via selective oxidation. The oxidative dehydrogenation of ethanol was chosen as test reaction, which shows that fine-tuning the synthesis of the new carbon catalysts allows to obtain a catalytic material with an attractive high selectivity (82 %) similar to a carbon nanotube reference, while achieving 10 times higher space-time yields at 330 °C. This new class of carbon materials is accessible via a technically scalable, reproducible synthetic pathway and exhibits spherical particles with diameters around 100 µm, allowing unproblematic handling similar to classic non-nano catalysts.

17.
Chemistry ; 26(3): 691-698, 2020 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-31674083

RESUMEN

Metal-organic frameworks (MOFs) are a promising class of materials for many applications, due to their high chemical tunability and superb porosity. By growing MOFs as (thin-)films, additional properties and potential applications become available. Here, copper (II) 1,3,5-benzenetricarboxylate (Cu-BTC) metal-organic framework (MOF) thin-films are reported, which were synthesized by spin-coating, resulting in "nanowebs", that is, fiber-like structures. These surface-mounted MOFs (SURMOFs) were studied by using photoinduced force microscopy (PiFM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The optimal concentration of precursors (10 mm) was determined that resulted in chemically homogeneous, pure nanowebs. Furthermore, the morphology and (un)coordinated Cu sites in the web were tuned by varying the rotation speed of the spin-coating process. X-ray diffraction (XRD) analysis showed that rotation speeds ≥2000 rpm (with precursors in a water/ethanol solution) generate the catena-triaqua-µ-(1,3,5-benzenetricarboxylate)-copper(II), or Cu(BTC)(H2 O)3 coordination polymer. X-ray photoelectron spectroscopy (XPS) highlighted the strong decrease in number of (defective) Cu+ sites, as the nanowebs mainly consist of coordinated Cu2+ Lewis acid sites (LAS) and organic linker-linker, for example, hydrogen-bonding, interactions. Finally, the Lewis-acidic character of the Cu sites is illustrated by testing the films as catalysts in the isomerization of α-pinene oxide. The higher number of LAS (≥3000 rpm), result in higher campholenic aldehyde selectivity reaching up to 87.7 %. Furthermore, the strength of a combined micro- and spectroscopic approach in understanding the nature of MOF thin-films in a spatially resolved manner is highlighted.

18.
Nanotechnology ; 31(25): 255603, 2020 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-32056974

RESUMEN

The patterned growth of transition metal dichalcogenides (TMDs) and their lateral heterostructures is paramount for the fabrication of application-oriented electronics and optoelectronics devices. However, the large scale patterned growth of TMDs remains challenging. Here, we demonstrate the synthesis of patterned polycrystalline 2D MoS2 thin films on device ready SiO2/Si substrates, eliminating any etching and transfer steps using a combination of plasma enhanced atomic layer deposition (PEALD) and thermal sulfurization. As an inherent advantage of ALD, precise thickness control ranging from a monolayer to few-layered MoS2 has been achieved. Furthermore, uniform films with exceptional conformality over 3D structures are obtained. Finally, the approach has been leveraged to obtain in-plane lateral heterostructures of 2D MoS2 and WS2 thin films over a large area which opens up an avenue for their direct integration in future nano- and opto-electronic device applications.

19.
Int J Immunogenet ; 47(1): 13-23, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31903698

RESUMEN

Currently, stem cell donor registries include more than 35 million potential donors worldwide to provide HLA-matched stem cell products for patients in need of an unrelated donor transplant. DKMS is a leading stem cell donor registry with more than 9 million donors from Germany, Poland, the United States, the United Kingdom, India and Chile. DKMS donors have donated hematopoietic stem cells more than 80,000 times. Many aspects of donor registry work are closely related to topics from immunogenetics or population genetics. In this two-part review article, we describe, analyse and discuss these areas of donor registry work by using the example of DKMS. Part 1 of the review gives a general overview on DKMS and includes typical donor registry activities with special focus on the HLA system: high-throughput HLA typing of potential stem cell donors, HLA haplotype frequencies and resulting matching probabilities, and donor file optimization with regard to HLA diversity.


Asunto(s)
Trasplante de Células Madre Hematopoyéticas , Prueba de Histocompatibilidad/métodos , Sistema de Registros , Donante no Emparentado , Chile , Genética de Población , Alemania , Antígenos HLA/genética , Antígenos HLA/inmunología , Haplotipos , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Inmunogenética , India , Polonia , Reino Unido , Estados Unidos
20.
Int J Immunogenet ; 47(2): 139-148, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32034894

RESUMEN

DKMS is a leading stem cell donor registry with more than 9 million donors. Donor registry activities share many touch points with topics from immunogenetics or population genetics. In this two-part review article, we deal with these aspects of donor registry work by using the example of DKMS. In the second part of the review, we focus on donor typing of non-HLA genes, the impact of donor age, gender and CMV serostatus on donation probabilities, the identification of novel HLA, KIR and MIC alleles by high-throughput donor typing, the activities of the Collaborative Biobank and pharmacogenetics in the donor registry context.


Asunto(s)
Antígenos HLA/genética , Sistema de Registros , Células Madre/inmunología , Donantes de Tejidos , Alelos , Tipificación y Pruebas Cruzadas Sanguíneas , Genotipo , Trasplante de Células Madre Hematopoyéticas , Prueba de Histocompatibilidad , Inmunogenética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA