In this review we present new concepts and recent progress in the application of semiconductor quantum dots (QD) as labels in two important areas of biology, bioimaging and biosensing. We analyze the ...biologically relevant properties of QDs focusing on the following topics: QD surface treatment and stability, labeling of cellular structures and receptors with QDs, incorporation of QDs in living cells, cytotoxicity of QDs and influence of the biological environment on the biological and optical properties of QDs. Initially, we consider utilization of QDs as agents in high-resolution bioimaging techniques that can provide information at the molecular levels. The diverse range of modern live-cell QD-based imaging techniques with resolution far beyond the diffraction limit of light is examined. In each technique, we discuss the pros and cons of QD use and deliberate how QDs can be further engineered to facilitate their application in the respective imaging techniques and to produce significant improvements in resolution. Then we review QD-based point-of-care bioassays, bioprobes, and biosensors designed in different formats ranging from analytic biochemistry assays and ELISA, to novel point-of-care smartphone integrated QD-based biotests. Here, a wide range of QD-based fluorescence bioassays with optical transduction, elecrochemiluminescence and photoelectrochemical assays are discussed. Finally, this review provides an analysis of the prospects of application of QDs in selected important areas of biology.
In this review we present new concepts and recent progress in the application of semiconductor quantum dots (QD) as labels in two important areas of biology, bioimaging and biosensing.
Genetic decoding is not 'frozen' as was earlier thought, but dynamic. One facet of this is frameshifting that often results in synthesis of a C-terminal region encoded by a new frame. Ribosomal ...frameshifting is utilized for the synthesis of additional products, for regulatory purposes and for translational 'correction' of problem or 'savior' indels. Utilization for synthesis of additional products occurs prominently in the decoding of mobile chromosomal element and viral genomes. One class of regulatory frameshifting of stable chromosomal genes governs cellular polyamine levels from yeasts to humans. In many cases of productively utilized frameshifting, the proportion of ribosomes that frameshift at a shift-prone site is enhanced by specific nascent peptide or mRNA context features. Such mRNA signals, which can be 5' or 3' of the shift site or both, can act by pairing with ribosomal RNA or as stem loops or pseudoknots even with one component being 4 kb 3' from the shift site. Transcriptional realignment at slippage-prone sequences also generates productively utilized products encoded trans-frame with respect to the genomic sequence. This too can be enhanced by nucleic acid structure. Together with dynamic codon redefinition, frameshifting is one of the forms of recoding that enriches gene expression.
Colloidal quantum dots for optoelectronics Litvin, A. P; Martynenko, I. V; Purcell-Milton, F ...
Journal of materials chemistry. A, Materials for energy and sustainability,
2017, Letnik:
5, Številka:
26
Journal Article
Recenzirano
This review is focused on new concepts and recent progress in the development of three major quantum dot (QD) based optoelectronic devices: photovoltaic cells, photodetectors and LEDs. In each ...application, we discuss recent champion devices with a range of architectures and discuss in detail the chronological steps taken to produce significant improvements in efficiency. We consider this relative to developments in colloidal quantum dots and their effects on these devices, covering alloyed, doped and core/shell QDs, quaternary Cu-Zn-In-S QDs, graphene and silicon QDs, and the wide range of highly promising NIR QDs. The diverse range of novel device designs is examined, including all-quantum dot devices, ternary hybrid compounds, plasmonic enhancements, and nano-heterojunction architectures. In addition, we analyse recent advances in charge transport layers, blocking layers, nanostructured photoanode fabrication and the importance of QD surface treatments. Throughout, we emphasise the use of hybrid composite materials including combinations of QDs with metal oxides, plasmonic nanoparticles, graphene and others. Finally, this review provides an analysis of prospects of these important selected quantum dot-based optoelectronic devices.
This review is focused on new concepts and recent progress in the development of three major quantum dot (QD) based optoelectronic devices: photovoltaic cells, photodetectors and LEDs.
The immune system has to cope with a wide range of irregularly shaped pathogens that can actively move (e.g., by flagella) and also dynamically remodel their shape (e.g., transition from yeast-shaped ...to hyphal fungi). The goal of this review is to draw general conclusions of how the size and geometry of a pathogen affect its uptake and processing by phagocytes of the immune system. We compared both theoretical and experimental studies with different cells, model particles, and pathogenic microbes (particularly fungi) showing that particle size, shape, rigidity, and surface roughness are important parameters for cellular uptake and subsequent immune responses, particularly inflammasome activation and T cell activation. Understanding how the physical properties of particles affect immune responses can aid the design of better vaccines.
Motivation: RNA editing is a phenomenon, which is responsible for the alteration of particular nucleotides in RNA sequences relative to their genomic templates. Recently, a large number of RNA ...editing instances in humans have been identified using bioinformatic screens and high-throughput experimental investigations utilizing next-generation sequencing technologies. However, the available data on RNA editing are not uniform and difficult to access. Results: Here, we describe a new database DARNED (DAtabase of RNa EDiting) that provides centralized access to available published data related to RNA editing. RNA editing locations are mapped on the reference human genome. The current release of the database contains information on approximately 42 000 human genome coordinates corresponding to RNA locations that undergo RNA editing, mostly involving adenosine-to-inosine (A-to-I) substitutions. The data can be queried using a range of genomic coordinates, their corresponding functional localization in RNA molecules Exons, Introns, CoDing Sequence (CDS) and UnTranslated Regions (UTRs) and information regarding tissue/organ/cell sources where RNA editing has been observed. It is also possible to obtain RNA editing information for a specific gene or an RNA molecule using corresponding accession numbers. Search results provide information on the number of expressed sequence tags (ESTs) supporting edited and genomic bases, functional localization of RNA editing and existence of known single nucleotide polymorphisms (SNPs). Editing data can be explored in UCSC and Ensembl genome browsers, in conjunction with additional data provided by these popular genome browsers. DARNED has been designed for researchers seeking information on RNA editing and for the developers of novel algorithms for its prediction. Availability: DARNED is accessible at http://darned.ucc.ie Contact: p.baranov@ucc.ie; brave.oval.pan@gmail.com
Acoustic Emission in Friction Baranov, Victor M; Kudryavtsev, Evgeny M; Sarychev, Gennady . A ...
2011, 2006, Letnik:
v.Volume 53
eBook
Acoustic Emission in Friction is devoted to acoustic, mainly ultrasonic, emission that occurs in friction of machine components. Its crucial novelty is in systematizing the advances in its use for ...monitoring technical systems, especially in the important nuclear power industry. Written by four well-known experts from the main nuclear research university in Russia, this book covers the following areas: * All the sources of acoustic emission in friction * The theory of acoustic emission * The effects of surface conditions, load and velocity on acoustic emission * The equipment for registration and monitoring of acoustic emission * Unique data from acoustic emission control under various testing conditions in friction units of machinery for nuclear industry machinery There is much emphasis on the comparatively new and rapidly developing tribology of nuclear power engineering. Although a substantial part of the experimental data relates to this specific field of engineering, the universality of the method is shown and its application is possible wherever the field inspection of friction units is necessary. * Calculation expressions describing main characteristics of AE registered in friction units * Describes new set-ups for studying the tribological behaviour of nuclear engineering materials * Presents the theory of the acoustic emission method in friction units
In healthy neurons, a mitochondrial membrane potential gradient exists whereby membrane potential is highest in the soma and decreases with distance from the nucleus. Correspondingly, distal ...mitochondria have more oxidative damage and slower protein import than somal mitochondria. Due to these differences, distal mitochondria have an intrinsic first stressor that somal mitochondria do not have, resulting in synaptic mitochondrial vulnerability.
A second stressor may result from mutant protein expression, situational stress, or aging, exacerbating vulnerable mitochondria activating stress responses. Under these conditions, distal mitochondria release cytochrome c and mitochondrial DNA, leading to compartmentalized sub-lethal caspase-3 activation and cytokine production.
In this two-hit mitochondrial-driven synaptic loss model, synapse vulnerability during neurodegeneration is explained as a superposition of pre-existing lower synaptic mitochondrial membrane potential (hit one) with additional mitochondrial stress (hit two). This two-hit mechanism occurs in synaptic mitochondria, activating signaling pathways leading to synaptic degeneration, as a potential preamble to neuronal death.
Free radicals are crucial indicators for stress and appear in all kinds of pathogenic conditions, including cancer, cardiovascular diseases, and infection. However, they are difficult to detect due ...to their reactivity and low abundance. We use relaxometry for the detection of radicals with subcellular resolution. This method is based on a fluorescent defect in a diamond, which changes its optical properties on the basis of the magnetic surroundings. This technique allows nanoscale MRI with unprecedented sensitivity and spatial resolution. Recently, this technique was used inside living cells from a cell line. Cell lines differ in terms of endocytic capability and radical production from primary cells derived from patients. Here we provide the first measurements of phagocytic radical production by the NADPH oxidase (NOX2) in primary dendritic cells from healthy donors. The radical production of these cells differs greatly between donors. We investigated the cell response to stimulation or inhibition.
Gas dynamic models of the interaction between the solar wind and cometary atmospheres are considered. Interest in the development of such models arose sharply after the beginning of the ...investigations of comets with the use of spacecraft launched at distances close to their surfaces. The instruments on this spacecraft gave the possibility to investigate experimentally the parameters of gas flow out from the cometary surfaces when the comets approach the Sun and its interaction with the solar wind plasma flow, which could not be made using only the spectral photometry. The beginning of such studies was started by almost instantaneous approaching of several space probes to Halley’s Comet on March 1986. Only after 28 years, the Rosetta spacecraft launched by the European Space Agency (ESA) along a complex trajectory have approached comet Churyumov–Gerasimenko and, maneuvering in the neighborhood of this comet during more than two years, it, in particular, have investigated the interaction of the cometary atmosphere and the solar wind.
Recent proteogenomic studies revealed extensive translation outside of annotated protein coding regions, such as non-coding RNAs and untranslated regions of mRNAs. This non-canonical translation is ...largely due to start codon plurality within the same RNA. This plurality is often due to the failure of some scanning ribosomes to recognize potential start codons leading to initiation downstream-a process termed leaky scanning. Codons other than AUG (non-AUG) are particularly leaky due to their inefficiency. Here we discuss our current understanding of non-AUG initiation. We argue for a near-ubiquitous role of non-AUG initiation in shaping the dynamic composition of mammalian proteomes.
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