Multicomponent supramolecular gels have great potential for optoelectronics. Ideally, we could control the self-assembly of multiple components across many length scales, from the primary assembled ...structures to how these are arranged in space. This would allow energy transfer between p-type and n-type fibers to be controlled. Usually, a single network is formed and analyzed. It is not clear how most networks could be modified, and certainly not how these might be differentiated. Here, we address both of these issues. We show how the different components in a multicomponent gel can be differentiated by small-angle neutron scattering using contrast-matching experiments. The rate of self-assembly can be used to vary the networks that are formed, leading directly to changes in the efficiency of electron transfer. The assembly kinetics can therefore be used to prepare different networks from the same primary building blocks and primary self-assembled structures. We expect that these advances will allow multicomponent systems to become effective electronic materials.
Low-molecular-weight gels are formed by the self-assembly of small molecules into fibrous networks that can immobilize a significant amount of solvent. Here, we focus on our work with a specific ...class of gelator, the functionalized dipeptide. We discuss the current state of the art in the area, focusing on how these materials can be controlled. We also highlight interesting and unusual observations and unanswered questions in the field.
Photoresponsive gelators Draper, Emily R; Adams, Dave J
Chemical communications,
01/2016, Letnik:
52, Številka:
53
Journal Article
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Low molecular weight gels can be responsive to a range of external stimuli. The use of light as an external stimulus to modify gels is of particular interest for a number of reasons. Light is a ...non-invasive trigger. For example, using light it is possible to spatially target a specific area of the gel leading to patterned gel surfaces. Here, we review the different approaches that have been used to form low molecular weight gels that respond to light.
We review the different approaches that have been used to form low molecular weight gels that respond to light.
Low molecular weight gels, or supramolecular gels, are formed when small molecules self-assemble into fibrous structures. Above a critical concentration, the entanglement and cross-linking of these ...structures leads to the formation of a self-supporting gel. There are many examples where a single component is used to form such gels. There is however an ever-increasing interest in using multiple components. Here, if each component is able to form a gel by itself, a range of fibre types are possible, formed by either random or specific associations between the low molecular weight gelators (LMWG). The properties of the networks will depend on how the LMWG assemble into the primary fibrous structures and then how these primary structures entangle. As such, to understand these gels, it is necessary to understand the networks across multiple length scales. Here, we discuss the current state of the art, the effectiveness of the different techniques that have been used, and hopefully provide the impetus for the field to move away from the cartoon-level discussion of assembly.
We discuss the current state of characterising multicomponent low molecular weight gels across all length scales, and the effectiveness of the different techniques that have been used.
Low-molecular-weight gels are currently a hugely important class of materials that are attracting significant interest. These gels are formed when small molecules self-assemble into one-dimensional ...structures that entangle and cross-link to form a network that is capable of immobilizing the solvent. Here, we critically discuss the current state of the art and highlight two key areas where we believe there is significant untapped potential. The first is the observation that the properties of the gels are highly process dependent, which means that it is possible to access materials with very different properties from a single gelator. Second, using multiple gelators offers the opportunity to prepare materials with a high degree of information content and with a wider range of properties. We aim to spark thought and discussion on these aspects.
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Gels are ubiquitous soft solids that are widely used in everyday life. Most gels are based on polymeric materials, as either entangled biopolymers or covalently cross-linked networks. Low-molecular-weight gels, or supramolecular gels, are another fascinating and useful class of gel. Here, the assembly of small molecules into a network immobilizes the solvent. These materials are becoming increasingly common and offer an opportunity to prepare interesting, designed, and responsive systems. Specific areas where we believe that there will be advances include exploiting the process-dependent nature of gelation and systems that utilize multiple gelators to access new properties.
Low-molecular-weight gelators are molecules that can self-assemble under specific conditions to form a network. This network immobilizes the solvent. Here, we discuss the state of the art and focus on the importance of formulation on the final gel properties as well as the opportunities that using multicomponent systems can provide.
We report a peptide-based multichromophoric hydrogelator system, wherein π-electron units with different inherent spectral energies are spatially controlled within peptidic 1-D nanostructures to ...create localized energy gradients in aqueous environments. This is accomplished by mixing different π-conjugated peptides prior to initiating self-assembly through solution acidification. We can vary the kinetics of the assembly and the degree of self-sorting through the choice of the assembly trigger, which changes the kinetics of acidification. The hydrolysis of glucono-δ-lactone (GdL) provides a slow pH drop that allows for stepwise triggering of peptide components into essentially self-sorted nanostructures based on subtle pK a differences, whereas HCl addition leads to a rapid formation of mixed components within a nanostructure. Using 1H NMR spectroscopy and fiber X-ray diffraction, we determine the conditions and peptide mixtures that favor self-sorting or intimate comixing. Photophysical investigations in the solution phase provide insight into the correlation of energy-transport processes occurring within the assemblies to the structural organization of the π-systems.
Abstract
In the context of the coronavirus disease 2019 (COVID-19) pandemic there has been an increase of the use of antigen-detection rapid diagnostic tests (Ag-RDT). The performance of Ag-RDT vary ...greatly between manufacturers and evaluating their analytical limit of detection (LOD) has become high priority. Here we describe a manufacturer-independent evaluation of the LOD of 19 marketed Ag-RDT using live SARS-CoV-2 spiked in different matrices: direct culture supernatant, a dry swab, and a swab in Amies. Additionally, the LOD using dry swab was investigated after 7 days’ storage at − 80 °C of the SARS-CoV-2 serial dilutions. An LOD of ≈ 5.0 × 10
2
pfu/ml (1.0 × 10
6
genome copies/ml) in culture media is defined as acceptable by the World Health Organization. Fourteen of 19 Ag-RDTs (ActiveXpress, Espline, Excalibur, Innova, Joysbio, Mologic, NowCheck, Orient, PanBio, RespiStrip, Roche, Standard-F, Standard-Q and Sure-Status) exceeded this performance criteria using direct culture supernatant applied to the Ag-RDT. Six Ag-RDT were not compatible with Amies media and a decreased sensitivity of 2 to 20-fold was observed for eleven tests on the stored dilutions at − 80 °C for 7 days. Here, we provide analytical sensitivity data to guide appropriate test and sample type selection for use and for future Ag-RDT evaluations.
We show here the first example of a hydrogel formed from a symmetrically functionalised diketopyrrolopyrrole aromatic core. Gelation is triggered by change in pH. Not only does this gelator form ...aggregated, entangled structures at low pH, but it also forms worm-like micelles at high pH. The structures at high pH can be aligned using shear to provide conductive materials.
Major depressive disorder (MDD) associated with chronic neglected tropical diseases (NTDs) has been identified as a significant and overlooked contributor to overall disease burden. Cutaneous ...leishmaniasis (CL) is one of the most prevalent and stigmatising NTDs, with an incidence of around 1 million new cases of active CL infection annually. However, the characteristic residual scarring (inactive CL) following almost all cases of active CL has only recently been recognised as part of the CL disease spectrum due to its lasting psychosocial impact.
We performed a multi-language systematic review of the psychosocial impact of active and inactive CL. We estimated inactive CL (iCL) prevalence for the first time using reported WHO active CL (aCL) incidence data that were adjusted for life expectancy and underreporting. We then quantified the disability (YLD) burden of co-morbid MDD in CL using MDD disability weights at three severity levels. Overall, we identified 29 studies of CL psychological impact from 5 WHO regions, representing 11 of the 50 highest burden countries for CL. We conservatively calculated the disability burden of co-morbid MDD in CL to be 1.9 million YLDs, which equalled the overall (DALY) disease burden (assuming no excess mortality in depressed CL patients). Thus, upon inclusion of co-morbid MDD alone in both active and inactive CL, the DALY burden was seven times higher than the latest 2016 Global Burden of Disease study estimates, which notably omitted both psychological impact and inactive CL.
Failure to include co-morbid MDD and the lasting sequelae of chronic NTDs, as exemplified by CL, leads to large underestimates of overall disease burden.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked enzymopathy caused by mutations in the G6PD gene. A medical concern associated with G6PD deficiency is acute hemolytic anemia ...induced by certain foods, drugs, and infections. Although phenotypic tests can correctly identify hemizygous males, as well as homozygous and compound heterozygous females, heterozygous females with a wide range of G6PD activity may be misclassified as normal. This study aimed to develop multiplex high-resolution melting (HRM) analyses to enable the accurate detection of G6PD mutations, especially among females with heterozygous deficiency. Multiplex HRM assays were developed to detect six G6PD variants, i.e., G6PD Gaohe (c.95A>G), G6PD Chinese-4 (c.392G>T), G6PD Mahidol (c.487G>A), G6PD Viangchan (c.871G>A), G6PD Chinese-5 (c.1024C>T), and G6PD Union (c.1360C>T) in two reactions. The assays were validated and then applied to genotype G6PD mutations in 248 Thai females. The sensitivity of the HRM assays developed was 100% 95% confidence interval (CI): 94.40%-100% with a specificity of 100% (95% CI: 88.78%-100%) for detecting these six mutations. The prevalence of G6PD deficiency was estimated as 3.63% (9/248) for G6PD deficiency and 31.05% (77/248) for intermediate deficiency by phenotypic assay. The developed HRM assays identified three participants with normal enzyme activity as heterozygous for G6PD Viangchan. Interestingly, a deletion in intron 5 nucleotide position 637/638 (c.486-34delT) was also detected by the developed HRM assays. G6PD genotyping revealed a total of 12 G6PD genotypes, with a high prevalence of intronic variants. Our results suggested that HRM analysis-based genotyping is a simple and reliable approach for detecting G6PD mutations, and could be used to prevent the misdiagnosis of heterozygous females by phenotypic assay. This study also sheds light on the possibility of overlooking intronic variants, which could affect G6PD expression and contribute to enzyme deficiency.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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