Organo-metal halide perovskites (OMHPs) are materials with attractive properties for optoelectronics. They made a recent introduction in the photovoltaics world by methylammonium (MA) lead triiodide ...and show remarkably improved charge separation capabilities when chloride and bromide are added. Here we show how halide substitution in OMHPs with the nominal composition CH3NH3PbI2X, where X is I, Br, or Cl, influences the morphology, charge quantum yield, and local interaction with the organic MA cation. X-ray diffraction and photoluminescence data demonstrate that halide substitution affects the local structure in the OMHPs with separate MAPbI3 and MAPbCl3 phases. Raman spectroscopies as well as theoretical vibration calculations reveal that this at the same time delocalizes the charge to the MA cation, which can liberate the vibrational movement of the MA cation, leading to a more adaptive organic phase. The resonance Raman effect together with quantum chemical calculations is utilized to analyze the change in charge transfer mechanism upon electronic excitation and gives important clues for the mechanism of the much improved photovoltage and photocurrent also seen in the solar cell performance for the materials when chloride compounds are included in the preparation.
Duchenne Muscular Dystrophy (DMD) is a rapidly progressive, lethal neuromuscular disorder, present from birth, which occurs almost exclusively in males. We have reviewed contemporary evidence of ...burden, epidemiology, illness costs and treatment patterns of DMD. This systematic review adhered to published methods with information also sought from the web and contacting registries. Searches were carried out from 2005 to June 2015. The population of interest was individuals with clearly defined DMD or their carers.
Nine thousand eight hundred fifty titles were retrieved from searches. Fifty-eight studies were reviewed with three assessed as high, 33 as medium and 22 as low quality. We found two studies reporting birth and four reporting point prevalence, three reporting mortality, 41 reporting severity and/or progression, 18 reporting treatment patterns, 12 reporting quality of life, two reporting utility measures, three reporting costs of illness and three treatment guidelines. Birth prevalence ranged from 15.9 to 19.5 per 100,000 live births. Point prevalence per 100,000 males was for France, USA, UK and Canada, 10.9, 1.9, 2.2 and 6.1 respectively. A study of adult DMD patients at a centre in France found median survival for those born between 1970 and 1994 was 40.95 years compared to 25.77 years for those born between 1955 and 1969. Loss of ambulation occurred at a median age of 12 and ventilation starts at about 20 years. There was international variation in use of corticosteroids, scoliosis surgery, ventilation and physiotherapy. The economic cost of DMD climbs dramatically with disease progression - rising as much as 5.7 fold from the early ambulatory phase to the non-ambulatory phase in Germany.
This is the first systematic review of treatment, progression, severity and quality of life in DMD. It also provides the most recent description of the burden, epidemiology, illness costs and treatment patterns in DMD. There are evidence gaps, particularly in prevalence and mortality. People with DMD seem to be living longer, possibly due to corticosteroid use, cardiac medical management and ventilation. Future research should incorporate registry data to improve comparability across time and between countries and to investigate the quality of life impact as the condition progresses.
Next-generation sequencing (NGS) provides a better approach to gene expression profiling with several advantages. The power of NGS along with novel molecular techniques and computational tools allow ...the researchers to perform the gene expression profiling to reveal transcriptional complexity of an organism and answering several biological questions. Although many studies for gene expression profiling related to various aspects have been performed in animal systems revealing unprecedented levels of complexity of transcriptomes, their use is still limited in plant biology. This review describes the use of NGS technologies with respect to gene expression profiling, bioinformatics challenges associated with data analysis and advances made so far in the plant biology research. We anticipate many more studies in recent future, which will surely advance our understanding of the complexity of plant genomes.
Feldspars are an attractive alternative to quartz for extending the dose range, and for dating volcanic terrains such as on Mars and Iceland. Unfortunately, charge stored in the feldspar lattice ...undergoes anomalous fading leading to an underestimation in the dose estimates. In this paper we use the time-resolved optically stimulated luminescence (TR-OSL) technique to investigate the processes that give rise to the signal following infrared (IR), green and blue stimulation, with an objective to understand tunnelling and charge transport during thermo-optical excitations. We show that the TR-OSL shape is governed by the energy of excitation and the subsequent charge recombination route through the excited state of the trap, the band tail states or the conduction band. The role of band tail states in charge recombination is specifically examined using the signal shown to decay over several ms; we identify two dominant recombination routes, viz., phonon (0.05–0.06 eV) assisted diffusion, and quantum mechanical tunnelling, depending on the energy state of the detrapped electron. As would be expected, diffusion in the band tails is identical for both resonant and non-resonant excitations, where in the latter case the band tail state occupancy likely arises from thermalisation of conduction band electrons. The important outcome of this study is a comprehensive physical model based on a single dosimetric trap that successfully explains wide-ranging luminescence phenomena in feldspars, in particular, the luminescence efficiency and thermal partitioning of charge in different energy states and the subsequent recombination routes. The model predicts three different systematic approaches to preferentially sampling the most stable signal. We finally present evidence for a non-fading signal using one of these methods based on pulsed IR stimulation.
The effect of martensite morphology and distribution in a ferrite matrix on the mechanical properties and the damage accumulation in uniaxial tension was investigated in two different ...automotive-grade dual phase DP600 steels. The two sheet steels had roughly 20% volume fraction of martensite but dissimilar chemical composition. A detailed analysis of microstructure and damage accumulation has been conducted as a function of strain. SEM analysis revealed that voids nucleation occurs by martensite cracking, separation of adjacent martensite regions, or by decohesion at the ferrite/martensite interface. Martensite morphology and distribution had a significant influence in the accumulation of damage. The steel with a more uniform distribution of martensite showed a slower rate of damage growth and a continuous void nucleation during the deformation process, which resulted in a higher void density before fracture. On the other hand, the steel with a centre-line of martensite through the sheet thickness exhibited accelerated void growth and catastrophic coalescence in the transverse orientation to the applied load.
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