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1.
Proc Natl Acad Sci U S A ; 118(30)2021 07 27.
Artículo en Inglés | MEDLINE | ID: mdl-34234013

RESUMEN

Development of effective vaccines against coronavirus disease 2019 (COVID-19) is a global imperative. Rapid immunization of the entire human population against a widespread, continually evolving, and highly pathogenic virus is an unprecedented challenge, and different vaccine approaches are being pursued. Engineered filamentous bacteriophage (phage) particles have unique potential in vaccine development due to their inherent immunogenicity, genetic plasticity, stability, cost-effectiveness for large-scale production, and proven safety profile in humans. Herein we report the development and initial evaluation of two targeted phage-based vaccination approaches against SARS-CoV-2: dual ligand peptide-targeted phage and adeno-associated virus/phage (AAVP) particles. For peptide-targeted phage, we performed structure-guided antigen design to select six solvent-exposed epitopes of the SARS-CoV-2 spike (S) protein. One of these epitopes displayed on the major capsid protein pVIII of phage induced a specific and sustained humoral response when injected in mice. These phage were further engineered to simultaneously display the peptide CAKSMGDIVC on the minor capsid protein pIII to enable their transport from the lung epithelium into the systemic circulation. Aerosolization of these "dual-display" phage into the lungs of mice generated a systemic and specific antibody response. In the second approach, targeted AAVP particles were engineered to deliver the entire S protein gene under the control of a constitutive CMV promoter. This induced tissue-specific transgene expression, stimulating a systemic S protein-specific antibody response in mice. With these proof-of-concept preclinical experiments, we show that both targeted phage- and AAVP-based particles serve as robust yet versatile platforms that can promptly yield COVID-19 vaccine prototypes for translational development.


Asunto(s)
Bacteriófagos/genética , Vacunas contra la COVID-19/administración & dosificación , COVID-19/prevención & control , Programas de Inmunización , Administración por Inhalación , Animales , Vacunas contra la COVID-19/química , Vacunas contra la COVID-19/inmunología , Dependovirus/genética , Almacenaje de Medicamentos , Femenino , Programas de Inmunización/métodos , Inmunogenicidad Vacunal , Ratones , Ratones Endogámicos BALB C , Prueba de Estudio Conceptual , Temperatura
2.
Environ Microbiol ; 25(12): 3207-3224, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37732569

RESUMEN

The sponge microbiome underpins host function through provision and recycling of essential nutrients in a nutrient poor environment. Genomic data suggest that carbohydrate degradation, carbon fixation, nitrogen metabolism, sulphur metabolism and supplementation of B-vitamins are central microbial functions. However, validation beyond the genomic potential of sponge symbiont pathways is rarely explored. To evaluate metagenomic predictions, we sequenced the metagenomes and metatranscriptomes of three common coral reef sponges: Ircinia ramosa, Ircinia microconulosa and Phyllospongia foliascens. Multiple carbohydrate active enzymes were expressed by Poribacteria, Bacteroidota and Cyanobacteria symbionts, suggesting these lineages have a central role in assimilating dissolved organic matter. Expression of entire pathways for carbon fixation and multiple sulphur compound transformations were observed in all sponges. Gene expression for anaerobic nitrogen metabolism (denitrification and nitrate reduction) were more common than aerobic metabolism (nitrification), where only the I. ramosa microbiome expressed the nitrification pathway. Finally, while expression of the biosynthetic pathways for B-vitamins was common, the expression of additional transporter genes was far more limited. Overall, we highlight consistencies and disparities between metagenomic and metatranscriptomic results when inferring microbial activity, while uncovering new microbial taxa that contribute to the health of their sponge host via nutrient exchange.


Asunto(s)
Cianobacterias , Microbiota , Poríferos , Animales , Filogenia , Cianobacterias/genética , Microbiota/genética , Vitaminas/metabolismo , Carbohidratos , Simbiosis
3.
Diabetes Obes Metab ; 25(6): 1464-1472, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36700392

RESUMEN

AIM: Randomized trials reporting 5-year outcomes have shown bariatric surgery  to induce diabetes remission and improve cardiovascular risk. However, the longer-term effects of surgery are uncertain, with only one randomized trial reporting 10-year diabetes outcomes in people with obesity. We aimed to compare 10-year diabetes outcomes of people who are overweight but not obese, randomly assigned to receive either multidisciplinary diabetes care, or multidisciplinary diabetes care combined with gastric band (GB) surgery. METHODS: Between 2009 and 2011, 51 adults were randomized. After 5 years, they were discharged to receive community care and reassessed after 10 years. The primary outcome was diabetes remission, defined as glycated haemoglobin (HbA1c) <6.5% (48 mmol/mol) without glucose-lowering medication. RESULTS: Forty-one participants (20 medical and 21 GB) completed the 10-year assessment. The median (Q1, Q3) weight loss in the GB group was 9.8 (6.7, 16.3)% at 10 years compared with 5.6 (3.4, 7.6)% in the medical group (median difference 4.2%; p = .008). Diabetes remission occurred in five GB participants and no medical participants (relative risk 0.76, 95% CI: 0.55-0.93, p = .048). GB participants used fewer glucose-lowering medications at 10 years but HbA1c, fasting glucose, calculated cardiovascular risk, quality-of-life and incident diabetes complications did not differ significantly between the groups. CONCLUSION: When compared with medical care, GB surgery achieved greater weight loss and modestly increased the likelihood of diabetes remission. However, it did not improve HbA1c, cardiovascular risk or quality of life.


Asunto(s)
Cirugía Bariátrica , Diabetes Mellitus Tipo 2 , Adulto , Humanos , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/epidemiología , Diabetes Mellitus Tipo 2/terapia , Sobrepeso/complicaciones , Sobrepeso/terapia , Hemoglobina Glucada , Calidad de Vida , Resultado del Tratamiento , Obesidad/complicaciones , Obesidad/epidemiología , Obesidad/cirugía , Glucosa , Pérdida de Peso
4.
Clin Infect Dis ; 73(10): 1906-1908, 2021 11 16.
Artículo en Inglés | MEDLINE | ID: mdl-33893480

RESUMEN

Over the first 2 months of 2021, vaccination coverage of staff at Hull Teaching Hospitals with BNT162b2 increased from 8.3% to 82.5% and was associated with a significant reduction in symptomatic and asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases. The proportion of positive lateral flow tests from asymptomatic screening was maintained over this period.


Asunto(s)
COVID-19 , Vacunas , Vacuna BNT162 , Vacunas contra la COVID-19 , Personal de Salud , Humanos , ARN Mensajero , SARS-CoV-2
5.
Eur J Immunol ; 50(6): 858-872, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32130727

RESUMEN

Host protective immunity against pathogenic Mycobacterium tuberculosis (Mtb) infection is variable and poorly understood. Both prior Mtb infection and BCG vaccination have been reported to confer some protection against subsequent infection and/or disease. However, the immune correlates of host protection with or without BCG vaccination remain poorly understood. Similarly, the host response to concomitant infection with mixed Mtb strains is unclear. In this study, we used the rabbit model to examine the host response to various infectious doses of virulent Mtb HN878 with and without prior BCG vaccination, as well as simultaneous infection with a mixture of two Mtb clinical isolates HN878 and CDC1551. We demonstrate that both the ability of host immunity to control pulmonary Mtb infection and the protective efficacy of BCG vaccination against the progression of Mtb infection to disease is dependent on the infectious inoculum. The host response to infection with mixed Mtb strains mirrors the differential responses seen during infection with each of the strains alone. The protective response mounted against a hyperimmunogenic Mtb strain has a limited impact on the control of disease caused by a hypervirulent strain. This preclinical study will aid in predicting the success of any vaccination strategy and in optimizing TB vaccines.


Asunto(s)
Vacuna BCG/inmunología , Mycobacterium tuberculosis/inmunología , Tuberculosis Pulmonar/prevención & control , Animales , Modelos Animales de Enfermedad , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/patogenicidad , Conejos , Especificidad de la Especie , Tuberculosis Pulmonar/genética , Tuberculosis Pulmonar/inmunología
6.
Mol Ecol ; 30(15): 3768-3782, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34060182

RESUMEN

Marine invertebrates harbour a complex suite of bacterial and archaeal symbionts, a subset of which are probably linked to host health and homeostasis. Within a complex microbiome it can be difficult to tease apart beneficial or parasitic symbionts from nonessential commensal or transient microorganisms; however, one approach is to detect strong cophylogenetic patterns between microbial lineages and their respective hosts. We employed the Procrustean approach to cophylogeny (PACo) on 16S rRNA gene derived microbial community profiles paired with COI, 18S rRNA and ITS1 host phylogenies. Second, we undertook a network analysis to identify groups of microbes that were co-occurring within our host species. Across 12 coral, 10 octocoral and five sponge species, each host group and their core microbiota (50% prevalence within host species replicates) had a significant fit to the cophylogenetic model. Independent assessment of each microbial genus and family found that bacteria and archaea affiliated to Endozoicomonadaceae, Spirochaetaceae and Nitrosopumilaceae have the strongest cophylogenetic signals. Further, local Moran's I measure of spatial autocorrelation identified 14 ASVs, including Endozoicomonadaceae and Spirochaetaceae, whose distributions were significantly clustered by host phylogeny. Four co-occurring subnetworks were identified, each of which was dominant in a different host group. Endozoicomonadaceae and Spirochaetaceae ASVs were abundant among the subnetworks, particularly one subnetwork that was exclusively comprised of these two bacterial families and dominated the octocoral microbiota. Our results disentangle key microbial interactions that occur within complex microbiomes and reveal long-standing, essential microbial symbioses in coral reef invertebrates.


Asunto(s)
Antozoos , Arrecifes de Coral , Animales , Antozoos/genética , Archaea/genética , Bacterias/genética , Humanos , Invertebrados , Filogenia , ARN Ribosómico 16S/genética , Simbiosis/genética
7.
Inorg Chem ; 60(10): 7573-7583, 2021 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-33949858

RESUMEN

This work investigates tuning of the molecular structure of a series of O-alkylxanthato zinc and cadmium precursor complexes to enhance production of ZnS and CdS materials. The structures of several bis(O-alkylxanthato) cadmium(II) complexes (8-13) and bis(O-alkyl xanthato)zinc(II) complexes (18 and 19) are reported based on single crystal X-ray diffraction data. CdS and ZnS films were produced by the spin-coating of these metal complexes followed by their thermal decomposition to the corresponding metal sulfides. Thin films of CdS were deposited by spin-coating the bis(O-alkylxanthato) cadmium(II) precursors (7-13) on glass substrates, followed by annealing at 300 °C for 60 min. Thin films of ZnS were deposited by spin-coating bis(O-alkylxanthato) zinc(II) (14-20), followed by annealing at 200 °C for 60 min. The molecular complexes and solid state materials are characterized using a range of techniques including single-crystal X-ray diffraction, pXRD, EDS and XPS, DSC and TGA, UV-vis and PL spectroscopies, and electron microscopy. These techniques provided information on the influence of alkyl chain length on the thermal conditions required to fabricate metal sulfide films as well as film properties such as film quality, and morphology. For example, the obtained crystallite size of metal sulfide films formed is correlated to the hydrocarbon chain length of xanthate ligands in the precursor. The behavior of the complexes under thermal stress was therefore studied in detail. DTA and TGA profiles explain the relationship between hydrocarbon chain length, decomposition temperatures, and the energies required for decomposition. A higher decomposition temperature for complexes with longer hydrocarbon chains is observed compared to complexes with shorter hydrocarbon chains. Band-gap energies calculated from the optical absorption spectra alongside steady state and time-resolved photoluminescence studies are reported for CdS films.

8.
Nature ; 526(7574): 542-5, 2015 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-26490619

RESUMEN

Tidal forces close to massive black holes can violently disrupt stars that make a close approach. These extreme events are discovered via bright X-ray and optical/ultraviolet flares in galactic centres. Prior studies based on modelling decaying flux trends have been able to estimate broad properties, such as the mass accretion rate. Here we report the detection of flows of hot, ionized gas in high-resolution X-ray spectra of a nearby tidal disruption event, ASASSN-14li in the galaxy PGC 043234. Variability within the absorption-dominated spectra indicates that the gas is relatively close to the black hole. Narrow linewidths indicate that the gas does not stretch over a large range of radii, giving a low volume filling factor. Modest outflow speeds of a few hundred kilometres per second are observed; these are below the escape speed from the radius set by variability. The gas flow is consistent with a rotating wind from the inner, super-Eddington region of a nascent accretion disk, or with a filament of disrupted stellar gas near to the apocentre of an elliptical orbit. Flows of this sort are predicted by fundamental analytical theory and more recent numerical simulations.

9.
BMC Genomics ; 21(1): 862, 2020 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-33276723

RESUMEN

BACKGROUND: Over the last decade, the rapid development of high-throughput sequencing platforms has accelerated species description and assisted morphological classification through DNA barcoding. However, the current high-throughput DNA barcoding methods cannot obtain full-length barcode sequences due to read length limitations (e.g. a maximum read length of 300 bp for the Illumina's MiSeq system), or are hindered by a relatively high cost or low sequencing output (e.g. a maximum number of eight million reads per cell for the PacBio's SEQUEL II system). RESULTS: Pooled cytochrome c oxidase subunit I (COI) barcodes from individual specimens were sequenced on the MGISEQ-2000 platform using the single-end 400 bp (SE400) module. We present a bioinformatic pipeline, HIFI-SE, that takes reads generated from the 5' and 3' ends of the COI barcode region and assembles them into full-length barcodes. HIFI-SE is written in Python and includes four function modules of filter, assign, assembly and taxonomy. We applied the HIFI-SE to a set of 845 samples (30 marine invertebrates, 815 insects) and delivered a total of 747 fully assembled COI barcodes as well as 70 Wolbachia and fungi symbionts. Compared to their corresponding Sanger sequences (72 sequences available), nearly all samples (71/72) were correctly and accurately assembled, including 46 samples that had a similarity score of 100% and 25 of ca. 99%. CONCLUSIONS: The HIFI-SE pipeline represents an efficient way to produce standard full-length barcodes, while the reasonable cost and high sensitivity of our method can contribute considerably more DNA barcodes under the same budget. Our method thereby advances DNA-based species identification from diverse ecosystems and increases the number of relevant applications.


Asunto(s)
Código de Barras del ADN Taxonómico , Ecosistema , Animales , ADN , Secuenciación de Nucleótidos de Alto Rendimiento , Insectos
10.
PLoS Pathog ; 14(8): e1007223, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-30161232

RESUMEN

Foam cells are lipid-laden macrophages that contribute to the inflammation and tissue damage associated with many chronic inflammatory disorders. Although foam cell biogenesis has been extensively studied in atherosclerosis, how these cells form during a chronic infectious disease such as tuberculosis is unknown. Here we report that, unlike the cholesterol-laden cells of atherosclerosis, foam cells in tuberculous lung lesions accumulate triglycerides. Consequently, the biogenesis of foam cells varies with the underlying disease. In vitro mechanistic studies showed that triglyceride accumulation in human macrophages infected with Mycobacterium tuberculosis is mediated by TNF receptor signaling through downstream activation of the caspase cascade and the mammalian target of rapamycin complex 1 (mTORC1). These features are distinct from the known biogenesis of atherogenic foam cells and establish a new paradigm for non-atherogenic foam cell formation. Moreover, they reveal novel targets for disease-specific pharmacological interventions against maladaptive macrophage responses.


Asunto(s)
Aterosclerosis/patología , Células Espumosas/metabolismo , Células Espumosas/patología , Metabolismo de los Lípidos/fisiología , Tuberculosis/inmunología , Tuberculosis/metabolismo , Animales , Aterosclerosis/metabolismo , Callithrix , Células Cultivadas , Humanos , Inflamación/metabolismo , Inflamación/patología , Macrófagos/metabolismo , Macrófagos/patología , Conejos
11.
Inorg Chem ; 59(21): 15796-15806, 2020 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-33044071

RESUMEN

Four 3d-4f hetero-polymetallic complexes [Fe2Ln2((OCH2)3CR)2(O2CtBu)6(H2O)4] (where Ln = La (1 and 2) and Gd (3 and 4); and R = Me (1 and 3) and Et (2 and 4)) are synthesized and analyzed using elemental analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis, and SQUID magnetometry. Crystal structures are obtained for both methyl derivatives and show that the complexes are isostructural and adopt a defective dicubane topology. The four heavy metals are connected with two alkoxide bridges. These four precursors are used as single-source precursors to prepare rare-earth orthoferrite pervoskites of the form LnFeO3. Thermal decomposition in a ceramic boat in a tube furnace gives orthorhombic LnFeO3 powders using optimized temperatures and decomposition times: LaFeO3 formed at 650 °C over 30 min, whereas GdFeO3 formed at 750 °C over 18 h. These materials are structurally characterized using powder X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray map spectroscopy, and SQUID magnetometry. EDX spectroscopy mapping reveals a homogeneous spatial distribution of elements for all four materials consistent with LnFeO3. Magnetic measurements on complexes 1-4 confirm the presence of weak antiferromagnetic coupling between the central Fe(III) ions of the clusters and negligible ferromagnetic interaction with peripheral Gd(III) ions in 3 and 4. Zero-field-cooled and field-cooled measurements of magnetization of LaFeO3 and GdFeO3 in the solid-state suggest that both materials are ferromagnetic, and both materials show open magnetic hysteresis loops at 5 and 300 K, with Msat higher than previously reported for these nanomaterials. We conclude that this is a new and facile low temperature route to these important magnetic materials that is potentially universal, limited only by what metals can be programmed into the precursor complexes.

12.
J Emerg Nurs ; 46(5): 682-692, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31955924

RESUMEN

INTRODUCTION: ED crowding is a complex phenomenon that presents many challenges to patients, hospitals, and staff. Using Lewin's change model, we implemented an ED improvement plan, including an innovative bed traffic control and improved flow system. We hypothesized that this plan would reduce door-to-provider time and emergency medical service-offloading time, decrease the length of stay and number of patients leaving without being seen by a physician, and increase overall patient satisfaction. METHODS: We examined the ED improvement plan's impact on institutional throughput metrics over a 4-year period (2015-2019). Data on door-to-provider time, door-to-discharge time, patient volume, leaving without being seen by a physician, and patient satisfaction by Press Ganey were analyzed. RESULTS: Between 2015 and 2018, the median door-to-provider time decreased 56.9% and the median door-to-discharge time decreased 29.6%. Percentage of patients who left without being seen by a physician decreased 73.8%. In 2018, the patient satisfaction rank increased by 16 points (84.2% increase). Emergency medical services-offloading time decreased significantly, prompting a change of the 30-minute cutoff to 20 minutes. In 2018, 0.84% of patients had an offloading time of more than 20 minutes. Preliminary 2019 data show maintenance of this trend for all hospital metrics. DISCUSSION: Implementing a pod system, with flow and bed placement managed by bed traffic control, reduced door-to-provider time, door-to-discharge time, leaving without being seen by a physician, emergency medical service-offload time, and increased patient satisfaction. Our results may provide a model for other emergency departments to effectively manage the challenges of crowding.


Asunto(s)
Ocupación de Camas , Aglomeración , Servicio de Urgencia en Hospital/organización & administración , Mejoramiento de la Calidad , Femenino , Hospitales Urbanos , Humanos , Tiempo de Internación/estadística & datos numéricos , Masculino , Pacientes Desistentes del Tratamiento/estadística & datos numéricos , Satisfacción del Paciente , Tiempo de Tratamiento/estadística & datos numéricos , Triaje
13.
Artículo en Inglés | MEDLINE | ID: mdl-30803965

RESUMEN

Fluoroquinolones represent the pillar of multidrug-resistant tuberculosis (MDR-TB) treatment, with moxifloxacin, levofloxacin, or gatifloxacin being prescribed to MDR-TB patients. Recently, several clinical trials of "universal" drug regimens, aiming to treat drug-susceptible and drug-resistant TB, have included a fluoroquinolone. In the absence of clinical data comparing their side-by-side efficacies in controlled MDR-TB trials, a pharmacological rationale is needed to guide the selection of the most efficacious fluoroquinolone. The present studies were designed to test the hypothesis that fluoroquinolone concentrations (pharmacokinetics) and activity (pharmacodynamics) at the site of infection are better predictors of efficacy than the plasma concentrations and potency measured in standard growth inhibition assays and are better suited to determinations of whether one of the fluoroquinolones outperforms the others in rabbits with active TB. We first measured the penetration of these fluoroquinolones in lung lesion compartments, and their potency against bacterial populations that reside in each compartment, to compute lesion-centric pharmacokinetic-pharmacodynamic (PK/PD) parameters. PK modeling methods were used to quantify drug penetration from plasma to tissues at human-equivalent doses. On the basis of these metrics, moxifloxacin emerged with a clear advantage, whereas plasma-based PK/PD favored levofloxacin (the ranges of the plasma AUC/MIC ratio [i.e., the area under the concentration-time curve over 24 h in the steady state divided by the MIC] are 46 to 86 for moxifloxacin and 74 to 258 for levofloxacin). A comparative efficacy trial in the rabbit model of active TB demonstrated the superiority of moxifloxacin in reducing bacterial burden at the lesion level and in sterilizing cellular and necrotic lesions. Collectively, these results show that PK/PD data obtained at the site of infection represent an adequate predictor of drug efficacy against TB and constitute the baseline required to explore synergies, antagonism, and drug-drug interactions in fluoroquinolone-containing regimens.


Asunto(s)
Antituberculosos/uso terapéutico , Fluoroquinolonas/uso terapéutico , Animales , Levofloxacino/uso terapéutico , Pruebas de Sensibilidad Microbiana , Moxifloxacino/uso terapéutico , Conejos , Espectrometría de Masas en Tándem , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico
14.
Methods ; 138-139: 76-84, 2018 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-29288801

RESUMEN

Quadrupolar relaxation of 2H (D) nuclear spins is a powerful probe of conformational dynamics in biological macromolecules. Deuterium relaxation rate constants are determined by the spectral density function for reorientation of the C-D bond vector at zero, single-quantum, and double-quantum 2H frequencies. In the present work, 2H relaxation rate constants were measured for an E. coli ribonuclease H [U-2H, 15N] ILV-[13CH2D] sample using 400, 500, 800, and 900 MHz NMR spectrometers and analyzed by three approaches to determine spectral density values. First, data recorded at each static magnetic field were analyzed independently. Second, data recorded at 400 and 800 MHz were analyzed jointly and data recorded at other fields were analyzed independently. Third, data recorded at 400 and 500 MHz were interpolated to 450 MHz, and the resulting two pairs of data, corresponding to 400 MHz/800 MHz and 450 MHz/900 MHz, were analyzed jointly. The second and third approaches rely on the identity between the double quantum frequency at the lower field and the single quantum frequency at the higher field. Spectral density values for 32 of the 48 resolvable ILV methyl resonances were fit by the Lipari-Szabo model-free formalism and used to validate the three methods. The three spectral density mapping methods performed equally well in cross validation with data recorded at 700 MHz. However, the third method yielded approximately 10-15% more precise estimates of model-free parameters and consequently provides a general strategy for analysis of 2H spin relaxation data in biological macromolecules.


Asunto(s)
Escherichia coli/enzimología , Resonancia Magnética Nuclear Biomolecular/métodos , Ribonucleasas/metabolismo , Deuterio , Conformación Proteica , Ribonucleasas/análisis , Ribonucleasas/química
15.
J Biomol NMR ; 70(4): 205-209, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29663108

RESUMEN

A TROSY-based NMR experiment is described for simultaneous measurement of the 15N longitudinal relaxation rate constant R1 and the {1H}-15N nuclear Overhauser enhancement. The experiment is based on the observation that the TROSY mixing pulse sequence element symmetrically exchanges 1H and 15N magnetizations. The accuracy of the proposed technique is validated by comparison to independent measurements of both relaxation parameters for the protein ubiquitin. The simultaneous experiment is approximately 20-33% shorter than conventional sequential measurements.


Asunto(s)
Isótopos de Nitrógeno , Resonancia Magnética Nuclear Biomolecular/métodos , Proteínas/química , Protones , Deuterio , Fenómenos Magnéticos , Ubiquitina/química
16.
Phys Chem Chem Phys ; 20(21): 14818-14827, 2018 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-29780991

RESUMEN

Electromotive force of photovoltaics is a key to define the output power density of photovoltaics. Multiple exciton generation (MEG) exhibited by semiconductor quantum dots (QDs) has great potential to enhance photovoltaic performance owing to the ability to generate more than one electron-hole pairs when absorbing a single photon. However, even in MEG-based photovoltaics, limitation of modifying the electromotive force exists due to the intrinsic electrochemical potential of the conduction band-edges of QDs. Here we report a pronouncedly improved photovoltaic performance by constructing a PbS QD-sensitized electrode that comprises plasmon-active Au nanoparticles embedded in a titanium dioxide thin film. Significant enhancement on electromotive force is characterized by the onset potential of photocurrent generation using MEG-effective PbS QDs with a narrow bandgap energy (Eg = 0.9 eV). By coupling with localized surface plasmon resonance (LSPR), such QDs exhibit improved photoresponses and the highest output power density over the other QDs with larger bandgap energies (Eg = 1.1 and 1.7 eV) under visible light irradiation. The wavelength-dependent onset potential and the output power density suggest effective electron injection owing to the enhanced density of electrons excited by energy overlapping between MEG and LSPR.

17.
Phys Chem Chem Phys ; 20(17): 12260-12271, 2018 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-29687131

RESUMEN

Blends of semiconducting nanocrystals and conjugated polymers continue to attract major research interest because of their potential applications in optoelectronic devices, such as solar cells, photodetectors and light-emitting diodes. In this study we investigate the surface structure, morphological and optoelectronic properties of multilayer films constructed from ZnO nanocrystals (NCs) and poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV). The effects of layer number and ZnO concentration (CZnO) used on the multilayer film properties are investigated. An optimised solvent blend enabled well-controlled layers to be sequentially spin coated and the construction of multilayer films containing six ZnO NC (Z) and MDMO-PPV (M) layers (denoted as (ZM)6). Contact angle data showed a strong dependence on CZnO and indicated distinct differences in the coverage of MDMO-PPV by the ZnO NCs. UV-visible spectroscopy showed that the MDMO-PPV absorption increased linearly with the number of layers in the films and demonstrates highly tuneable light absorption. Photoluminescence spectra showed reversible quenching as well as a surprising red-shift of the MDMO-PPV emission peak. Solar cells were constructed to probe vertical photo-generated charge transport. The measurements showed that (ZM)6 devices prepared using CZnO = 14.0 mg mL-1 had a remarkably high open circuit voltage of ∼800 mV. The device power conversion efficiency was similar to that of a control bilayer device prepared using a much thicker MDMO-PPV layer. The results of this study provide insight into the structure-optoelectronic property relationships of new semiconducting multilayer films which should also apply to other semiconducting NC/polymer combinations.

18.
Cochrane Database Syst Rev ; 1: CD000317, 2018 01 25.
Artículo en Inglés | MEDLINE | ID: mdl-29368795

RESUMEN

BACKGROUND: The first-line treatment in donor sperm treatment consists of inseminations that can be done by intrauterine insemination (IUI) or by intracervical insemination (ICI). OBJECTIVES: To compare the effectiveness and safety of intrauterine insemination (IUI) and intracervical insemination (ICI) in women who start donor sperm treatment. SEARCH METHODS: We searched the Cochrane Gynaecology and Fertility Group Trials Register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL in October 2016, checked references of relevant studies, and contacted study authors and experts in the field to identify additional studies. We searched PubMed, Google Scholar, the Grey literature, and five trials registers on 15 December 2017. SELECTION CRITERIA: We included randomised controlled trials (RCTs) reporting on IUI versus ICI in natural cycles or with ovarian stimulation, and RCTs comparing different cointerventions in IUI and ICI. We included cross-over studies if pre-cross-over data were available. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures recommended by Cochrane. We collected data on primary outcomes of live birth and multiple pregnancy rates, and on secondary outcomes of clinical pregnancy, miscarriage, and cancellation rates. MAIN RESULTS: We included six RCTs (708 women analysed) on ICI and IUI in donor sperm treatment. Two studies compared IUI and ICI in natural cycles, two studies compared IUI and ICI in gonadotrophin-stimulated cycles, and two studies compared timing of IUI and ICI. There was very low-quality evidence; the main limitations were risk of bias due to poor reporting of study methods, and serious imprecision.IUI versus ICI in natural cyclesThere was insufficient evidence to determine whether there was any clear difference in live birth rate between IUI and ICI in natural cycles (odds ratio (OR) 3.24, 95% confidence interval (CI) 0.12 to 87.13; 1 RCT, 26 women; very low-quality evidence). There was only one live birth in this study (in the IUI group). IUI resulted in higher clinical pregnancy rates (OR 6.18, 95% CI 1.91 to 20.03; 2 RCTs, 76 women; I² = 48%; very low-quality evidence).No multiple pregnancies or miscarriages occurred in this study.IUI versus ICI in gonadotrophin-stimulated cyclesThere was insufficient evidence to determine whether there was any clear difference in live birth rate between IUI and ICI in gonadotrophin-stimulated cycles (OR 2.55, 95% CI 0.72 to 8.96; 1 RCT, 43 women; very low-quality evidence). This suggested that if the chance of a live birth following ICI in gonadotrophin-stimulated cycles was assumed to be 30%, the chance following IUI in gonadotrophin-stimulated cycles would be between 24% and 80%. IUI may result in higher clinical pregnancy rates than ICI (OR 2.83, 95% CI 1.38 to 5.78; 2 RCTs, 131 women; I² = 0%; very low-quality evidence). IUI may be associated with higher multiple pregnancy rates than ICI (OR 2.77, 95% CI 1.00 to 7.69; 2 RCTs, 131 women; I² = 0%; very low-quality evidence). This suggested that if the risk of multiple pregnancy following ICI in gonadotrophin-stimulated cycles was assumed to be 10%, the risk following IUI would be between 10% and 46%.We found insufficient evidence to determine whether there was any clear difference between the groups in miscarriage rates in gonadotrophin-stimulated cycles (OR 1.97, 95% CI 0.43 to 9.04; 2 RCTs, overall 67 pregnancies; I² = 50%; very low-quality evidence).Timing of IUI and ICIWe found no studies that reported on live birth rates.We found a higher clinical pregnancy rate when IUI was timed one day after a rise in blood levels of luteinising hormone (LH) compared to IUI two days after a rise in blood levels of LH (OR 2.00, 95% CI 1.14 to 3.53; 1 RCT, 351 women; low-quality evidence). We found insufficient evidence to determine whether there was any clear difference in clinical pregnancy rates between ICI timed after a rise in urinary levels of LH versus a rise in basal temperature plus cervical mucus scores (OR 1.31, 95% CI 0.42 to 4.11; 1 RCT, 56 women; very low-quality evidence).Neither of these studies reported multiple pregnancy or miscarriage rates as outcomes. AUTHORS' CONCLUSIONS: There was insufficient evidence to determine whether there was a clear difference in live birth rates between IUI and ICI in natural or gonadotrophin-stimulated cycles in women who started with donor sperm treatment. There was insufficient evidence available for the effect of timing of IUI or ICI on live birth rates. Very low-quality data suggested that in gonadotrophin-stimulated cycles, ICI may be associated with a higher clinical pregnancy rate than IUI, but also with a higher risk of multiple pregnancy rate. We concluded that the current evidence was too limited to choose between IUI or ICI, in natural cycles or with ovarian stimulation, in donor sperm treatment.


Asunto(s)
Inseminación Artificial Heteróloga/métodos , Temperatura Corporal , Moco del Cuello Uterino , Femenino , Gonadotropinas/uso terapéutico , Humanos , Nacimiento Vivo/epidemiología , Hormona Luteinizante/sangre , Ciclo Menstrual/efectos de los fármacos , Embarazo , Índice de Embarazo , Embarazo Múltiple , Ensayos Clínicos Controlados Aleatorios como Asunto
19.
Artículo en Inglés | MEDLINE | ID: mdl-28696241

RESUMEN

Clinical trials and practice have shown that ethambutol is an important component of the first-line tuberculosis (TB) regime. This contrasts the drug's rather modest potency and lack of activity against nongrowing persister mycobacteria. The standard plasma-based pharmacokinetic-pharmacodynamic profile of ethambutol suggests that the drug may be of limited clinical value. Here, we hypothesized that this apparent contradiction may be explained by favorable penetration of the drug into TB lesions. First, we utilized novel in vitro lesion pharmacokinetic assays and predicted good penetration of the drug into lesions. We then employed mass spectrometry imaging and laser capture microdissection coupled to liquid chromatography and tandem mass spectrometry (LCM and LC/MS-MS, respectively) to show that ethambutol, indeed, accumulates in diseased tissues and penetrates the major human-like lesion types represented in the rabbit model of TB disease with a lesion-to-plasma exposure ratio ranging from 9 to 12. In addition, ethambutol exhibits slow but sustained passive diffusion into caseum to reach concentrations markedly higher than those measured in plasma at steady state. The results explain why ethambutol has retained its place in the first-line regimen, validate our in vitro lesion penetration assays, and demonstrate the critical importance of effective lesion penetration for anti-TB drugs. Our findings suggest that in vitro and in vivo lesion penetration evaluation should be included in TB drug discovery programs. Finally, this is the first time that LCM with LC-MS/MS has been used to quantify a small molecule at high spatial resolution in infected tissues, a method that can easily be extended to other infectious diseases.


Asunto(s)
Antituberculosos/farmacología , Etambutol/farmacología , Tuberculosis Pulmonar/tratamiento farmacológico , Animales , Cromatografía Liquida/métodos , Femenino , Humanos , Ratones , Ratones Endogámicos C57BL , Mycobacterium tuberculosis/efectos de los fármacos , Conejos , Espectrometría de Masas en Tándem/métodos , Resultado del Tratamiento
20.
Bioconjug Chem ; 28(5): 1422-1433, 2017 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-28436674

RESUMEN

The development of methods for conjugating a range of molecules to primary amine functional groups has revolutionized the fields of chemistry, biology, and material science. The primary amine is a key functional group and one of the most important nucleophiles and bases used in all of synthetic chemistry. Therefore, tremendous interest in the synthesis of molecules containing primary amines and strategies to devise chemical reactions to react with primary amines has been at the core of chemical research. In particular, primary amines are a ubiquitous functional group found in biological systems as free amino acids, as key side chain lysines in proteins, and in signaling molecules and metabolites and are also present in many natural product classes. Due to its abundance, the primary amine is the most convenient functional group handle in molecules for ligation to other molecules for a broad range of applications that impact all scientific fields. Because of the primary amine's central importance in synthetic chemistry, acid-base chemistry, redox chemistry, and biology, many methods have been developed to efficiently react with primary amines, including activated carboxylic acids, isothiocyanates, Michael addition type systems, and reaction with ketones or aldehydes followed by in situ reductive amination. Herein, we introduce a new traceless, high-yield, fast click-chemistry method based on the rapid and efficient trapping of amine groups via a functionalized dialdehyde group. The click reaction occurs in mild conditions in organic solvents or aqueous media and proceeds in high yield, and the starting dialdehyde reagent and resulting dialdehyde click conjugates are stable. Moreover, no catalyst or dialdehyde-activating group is required, and the only byproduct is water. The initial dialdehyde and the resulting conjugate are both straightforward to characterize, and the reaction proceeds with high atom economy. To demonstrate the broad scope of this new click-conjugation strategy, we designed a straightforward scheme to synthesize a suite of dialdehyde reagents. The dialdehyde molecules were used for applications in cell-surface engineering and for tailoring surfaces for material science applications. We anticipate the broad utility of the general dialdehyde click chemistry to primary amines in all areas of chemical research, ranging from polymers and bioconjugation to material science and nanoscience.


Asunto(s)
Aldehídos/química , Aminas/química , Química Clic/métodos , Aminación , Catálisis , Estructura Molecular , Oxidación-Reducción
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