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result(s) for
"Groves, James R."
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Probing carrier lifetimes in photovoltaic materials using subsurface two-photon microscopy
by
Connor, Stephen T.
,
Aloni, Shaul
,
Hardin, Brian E.
in
639/301/299/946
,
639/301/930/12
,
639/624/1111/1116
2013
Accurately measuring the bulk minority carrier lifetime is one of the greatest challenges in evaluating photoactive materials used in photovoltaic cells. One-photon time-resolved photoluminescence decay measurements are commonly used to measure lifetimes of direct bandgap materials. However, because the incident photons have energies higher than the bandgap of the semiconductor, most carriers are generated close to the surface, where surface defects cause inaccurate lifetime measurements. Here we show that two-photon absorption permits sub-surface optical excitation, which allows us to decouple surface and bulk recombination processes even in unpassivated samples. Thus with two-photon microscopy we probe the bulk minority carrier lifetime of photovoltaic semiconductors. We demonstrate how the traditional one-photon technique can underestimate the bulk lifetime in a CdTe crystal by 10× and show that two-photon excitation more accurately measures the bulk lifetime. Finally, we generate multi-dimensional spatial maps of optoelectronic properties in the bulk of these materials using two-photon excitation.
Journal Article
Imaging biomarker roadmap for cancer studies
by
Aerts, Hugo J. W. L.
,
Jayson, Gordon C.
,
Punwani, Shonit
in
631/154/309/2144
,
692/308/53
,
692/4028/67/2321
2017
Imaging biomarkers (IBs) are used extensively in drug development and cancer research, but important differences exist between IBs and biospecimen-derived biomarkers. A tailored 'roadmap' is required for the development of new IBs to be used either in clinical research or for decision-making in healthcare. In this Consensus statement, a group of experts assembled by CRUK and the EORTC present 14 key recommendations for accelerating the clinical translation of IBs.
Imaging biomarkers (IBs) are integral to the routine management of patients with cancer. IBs used daily in oncology include clinical TNM stage, objective response and left ventricular ejection fraction. Other CT, MRI, PET and ultrasonography biomarkers are used extensively in cancer research and drug development. New IBs need to be established either as useful tools for testing research hypotheses in clinical trials and research studies, or as clinical decision-making tools for use in healthcare, by crossing 'translational gaps' through validation and qualification. Important differences exist between IBs and biospecimen-derived biomarkers and, therefore, the development of IBs requires a tailored 'roadmap'. Recognizing this need, Cancer Research UK (CRUK) and the European Organisation for Research and Treatment of Cancer (EORTC) assembled experts to review, debate and summarize the challenges of IB validation and qualification. This consensus group has produced 14 key recommendations for accelerating the clinical translation of IBs, which highlight the role of parallel (rather than sequential) tracks of technical (assay) validation, biological/clinical validation and assessment of cost-effectiveness; the need for IB standardization and accreditation systems; the need to continually revisit IB precision; an alternative framework for biological/clinical validation of IBs; and the essential requirements for multicentre studies to qualify IBs for clinical use.
Journal Article
Metabolic potential of uncultured bacteria and archaea associated with petroleum seepage in deep-sea sediments
by
Chuvochina, Maria
,
Bernard, Bernie B.
,
Brooks, James M.
in
631/158/855
,
631/326/2565/2142
,
631/326/26
2019
The lack of microbial genomes and isolates from the deep seabed means that very little is known about the ecology of this vast habitat. Here, we investigate energy and carbon acquisition strategies of microbial communities from three deep seabed petroleum seeps (3 km water depth) in the Eastern Gulf of Mexico. Shotgun metagenomic analysis reveals that each sediment harbors diverse communities of chemoheterotrophs and chemolithotrophs. We recovered 82 metagenome-assembled genomes affiliated with 21 different archaeal and bacterial phyla. Multiple genomes encode enzymes for anaerobic oxidation of aliphatic and aromatic compounds, including those of candidate phyla Aerophobetes, Aminicenantes, TA06 and Bathyarchaeota. Microbial interactions are predicted to be driven by acetate and molecular hydrogen. These findings are supported by sediment geochemistry, metabolomics, and thermodynamic modelling. Overall, we infer that deep-sea sediments experiencing thermogenic hydrocarbon inputs harbor phylogenetically and functionally diverse communities potentially sustained through anaerobic hydrocarbon, acetate and hydrogen metabolism.
Little is known about the microbial ecology of the deep seabed. Here, Dong et al. predict metabolic capabilities and microbial interactions in deep seabed petroleum seeps using shotgun metagenomics, sediment geochemistry, metabolomics, and thermodynamic modelling.
Journal Article
Resilience of the Eastern African electricity sector to climate driven changes in hydropower generation
by
Rogner, H-Holger
,
Neumann, James E.
,
Broad, Oliver
in
704/106/694/2739
,
704/844/2739
,
704/844/841
2019
Notwithstanding current heavy dependence on gas-fired electricity generation in the Eastern African Power Pool (EAPP), hydropower is expected to play an essential role in improving electricity access in the region. Expansion planning of electricity infrastructure is critical to support investment and maintaining balanced consumer electricity prices. Variations in water availability due to a changing climate could leave hydro infrastructure stranded or result in underutilization of available resources. In this study, we develop a framework consisting of long-term models for electricity supply and water systems management, to assess the vulnerability of potential expansion plans to the effects of climate change. We find that the most resilient EAPP rollout strategy corresponds to a plan optimised for a slightly wetter climate compared to historical trends. This study demonstrates that failing to climate-proof infrastructure investments can result in significant electricity price fluctuations in selected countries (Uganda & Tanzania) while others, such as Egypt, are less vulnerable.
Hydropower generation in the Nile River Basin is vulnerable to climatic changes. Here, the authors assess infrastructure resilience of the Eastern African power pool (EAPP) to the effects of a changing climate and suggest that failing to climate-proof infrastructure investments can result in significant electricity price fluctuations.
Journal Article
common brain network links development, aging, and vulnerability to disease
2014
Significance Many evolutionary–developmental models have attempted to relate development and aging, with one popular hypothesis proposing that healthy age-related brain decline mirrors developmental maturation. But this elegant hypothesis has so far lacked clear and direct data to support it. Here, we describe intrinsic, entirely data-driven evidence that healthy brain degeneration and developmental process mirror one another in certain brain regions. Specifically, a data-driven decomposition of structural brain images in 484 healthy participants reveals a network of mainly higher-order regions that develop relatively late during adolescence, demonstrate accelerated degeneration in old age, and show heightened vulnerability to disorders that impact on brain structure during adolescence and aging. These results provide a fundamental link between development, aging, and disease processes in the brain.
Several theories link processes of development and aging in humans. In neuroscience, one model posits for instance that healthy age-related brain degeneration mirrors development, with the areas of the brain thought to develop later also degenerating earlier. However, intrinsic evidence for such a link between healthy aging and development in brain structure remains elusive. Here, we show that a data-driven analysis of brain structural variation across 484 healthy participants (8–85 y) reveals a largely—but not only—transmodal network whose lifespan pattern of age-related change intrinsically supports this model of mirroring development and aging. We further demonstrate that this network of brain regions, which develops relatively late during adolescence and shows accelerated degeneration in old age compared with the rest of the brain, characterizes areas of heightened vulnerability to unhealthy developmental and aging processes, as exemplified by schizophrenia and Alzheimer’s disease, respectively. Specifically, this network, while derived solely from healthy subjects, spatially recapitulates the pattern of brain abnormalities observed in both schizophrenia and Alzheimer’s disease. This network is further associated in our large-scale healthy population with intellectual ability and episodic memory, whose impairment contributes to key symptoms of schizophrenia and Alzheimer’s disease. Taken together, our results suggest that the common spatial pattern of abnormalities observed in these two disorders, which emerge at opposite ends of the life spectrum, might be influenced by the timing of their separate and distinct pathological processes in disrupting healthy cerebral development and aging, respectively.
Journal Article
Updating the study protocol: Insight 46 – a longitudinal neuroscience sub-study of the MRC National Survey of Health and Development – phases 2 and 3
2024
Background
Although age is the biggest known risk factor for dementia, there remains uncertainty about other factors over the life course that contribute to a person’s risk for cognitive decline later in life. Furthermore, the pathological processes leading to dementia are not fully understood. The main goals of Insight 46—a multi-phase longitudinal observational study—are to collect detailed cognitive, neurological, physical, cardiovascular, and sensory data; to combine those data with genetic and life-course information collected from the MRC National Survey of Health and Development (NSHD; 1946 British birth cohort); and thereby contribute to a better understanding of healthy ageing and dementia.
Methods/Design
Phase 1 of Insight 46 (2015–2018) involved the recruitment of 502 members of the NSHD (median age = 70.7 years; 49% female) and has been described in detail by Lane and Parker et al
.
2017. The present paper describes phase 2 (2018–2021) and phase 3 (2021–ongoing). Of the 502 phase 1 study members who were invited to a phase 2 research visit, 413 were willing to return for a clinic visit in London and 29 participated in a remote research assessment due to COVID-19 restrictions. Phase 3 aims to recruit 250 study members who previously participated in both phases 1 and 2 of Insight 46 (providing a third data time point) and 500 additional members of the NSHD who have not previously participated in Insight 46.
Discussion
The NSHD is the oldest and longest continuously running British birth cohort. Members of the NSHD are now at a critical point in their lives for us to investigate successful ageing and key age-related brain morbidities. Data collected from Insight 46 have the potential to greatly contribute to and impact the field of healthy ageing and dementia by combining unique life course data with longitudinal multiparametric clinical, imaging, and biomarker measurements. Further protocol enhancements are planned, including in-home sleep measurements and the engagement of participants through remote online cognitive testing. Data collected are and will continue to be made available to the scientific community.
Journal Article
Trans-ancestry meta-analyses identify rare and common variants associated with blood pressure and hypertension
by
Spector, Timothy D
,
Mohlke, Karen L
,
Vasan, Ramachandran S
in
45/43
,
631/208/205/2138
,
631/208/457
2016
Patricia Munroe, Joanna Howson and colleagues genotype ∼350,000 individuals and identify 30 new blood pressure– or hypertension-associated risk loci. Their analyses provide insights into the pathophysiology of hypertension and highlight new potential targets for clinical intervention.
High blood pressure is a major risk factor for cardiovascular disease and premature death. However, there is limited knowledge on specific causal genes and pathways. To better understand the genetics of blood pressure, we genotyped 242,296 rare, low-frequency and common genetic variants in up to 192,763 individuals and used ∼155,063 samples for independent replication. We identified 30 new blood pressure– or hypertension-associated genetic regions in the general population, including 3 rare missense variants in
RBM47
,
COL21A1
and
RRAS
with larger effects (>1.5 mm Hg/allele) than common variants. Multiple rare nonsense and missense variant associations were found in
A2ML1
, and a low-frequency nonsense variant in
ENPEP
was identified. Our data extend the spectrum of allelic variation underlying blood pressure traits and hypertension, provide new insights into the pathophysiology of hypertension and indicate new targets for clinical intervention.
Journal Article
Neural network-based study of structural, chemical and electronic properties of doped MoO3
by
Neupane, Mahesh R.
,
Weil, James D.
,
Cruz, Jenille
in
Adsorption
,
Applied and Technical Physics
,
Biomaterials
2021
Molybdenum trioxide (
MoO
3
) is a commonly implemented acceptor layer for the surface-doped diamond devices. This work proposes an approach to engineer the intrinsic electrochemical properties of the
MoO
3
surface through a substitutional doping technique to enhance the surface conductivity of the interfacing diamond surface. A neural network (NN) technique was used to identify the stable location of the dopants within the surface. The acidic properties of these doped surfaces were analyzed by evaluating the surface adsorption potential energy (APE). An analysis of the electronic properties of the doped
MoO
3
systems reveals that the dopants with the lower electronegativity contributed to the relatively enhanced p-type conductivity. Our atom-projected density of states (pDOS) reveals that the density of oxygen states around the valence band states not only increases the p-type conductivity, but also increases the acidic behavior in the doped
MoO
3
surface. In summary, our study on the doped
MoO
3
surface provides a new design space in the field of acceptor layer technology for the surface-doped diamond devices.
Graphical abstract
Journal Article
Conserving Biodiversity: Practical Guidance about Climate Change Adaptation Approaches in Support of Land-use Planning
by
Johnston, Kevin M.
,
Strittholt, James R.
,
Schmitz, Oswald J.
in
biodiversity
,
case studies
,
climate
2015
As species' geographic ranges and ecosystem functions are altered in response to climate change, there is a need to integrate biodiversity conservation approaches that promote natural adaptation into land use planning. Successful conservation will need to embrace multiple climate adaptation approaches, but to date they have not been conveyed in an integrated way to help support immediate conservation planning and action in the face of inherent spatial uncertainty about future conditions. Instead, these multiple approaches are often conveyed as competing or contradictory alternatives, when in fact, they are complementary. We present a framework that synthesizes six promising spatially explicit adaptation approaches for conserving biodiversity. We provide guidance on implementing these adaptation approaches and include case studies that highlight how biodiversity conservation can be used in planning. We conclude with general guidance on choosing appropriate climate adaptation approaches to amend for conservation planning.
Journal Article
International Consensus Statement on the diagnosis, multidisciplinary management and lifelong care of individuals with achondroplasia
by
Raggio Cathleen
,
Rossiter, Judith
,
Powell, Steven
in
Achondroplasia
,
Bone dysplasia
,
Children
2022
Achondroplasia, the most common skeletal dysplasia, is characterized by a variety of medical, functional and psychosocial challenges across the lifespan. The condition is caused by a common, recurring, gain-of-function mutation in FGFR3, the gene that encodes fibroblast growth factor receptor 3. This mutation leads to impaired endochondral ossification of the human skeleton. The clinical and radiographic hallmarks of achondroplasia make accurate diagnosis possible in most patients. However, marked variability exists in the clinical care pathways and protocols practised by clinicians who manage children and adults with this condition. A group of 55 international experts from 16 countries and 5 continents have developed consensus statements and recommendations that aim to capture the key challenges and optimal management of achondroplasia across each major life stage and sub-specialty area, using a modified Delphi process. The primary purpose of this first International Consensus Statement is to facilitate the improvement and standardization of care for children and adults with achondroplasia worldwide in order to optimize their clinical outcomes and quality of life.Achondroplasia is the most common skeletal dysplasia and is characterized by various lifelong clinical, functional and psychosocial challenges for affected individuals. This first International Consensus Statement on the care of children and adults with achondroplasia aims to facilitate the global standardization and improvement of achondroplasia clinical care.
Journal Article