Expression and purification of an adenylation domain from a eukaryotic nonribosomal peptide synthetase: Using structural genomics tools for a challenging target

Nonribosomal peptide synthetases (NRPSs) are large multimodular and multidomain enzymes that are involved in synthesising an array of molecules that are important in human and animal health. NRPSs are found in both bacteria and fungi but most of the research to date has focused on the bacterial enzymes. This is largely due to the technical challenges in producing active fungal NRPSs, which stem from their large size and multidomain nature. In order to target fungal NRPS domains for biochemical and structural characterisation, we tackled this challenge by using the cloning and expression tools of structural genomics to screen the many variables that can influence the expression and purification of proteins. Using these tools we have screened 32 constructs containing 16 different fungal NRPS domains or domain combinations for expression and solubility. Two of these yielded soluble protein with one, the third adenylation domain of the SidN NRPS (SidNA3) from the grass endophyte Neotyphodium lolii, being tractable for purification using Ni-affinity resin. The initial purified protein exhibited poor solution behaviour but optimisation of the expression construct and the buffer conditions used for purification, resulted in stable recombinant protein suitable for biochemical characterisation, crystallisation and structure determination

Mechanical properties of cancellous bone

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76183/1/AIAA-1971-111-853.pd

Quantum simulation of multiple-exciton generation in a nanocrystal by a single photon

We have shown theoretically that efficient multiple exciton generation (MEG) by a single photon can be observed in small nanocrystals (NCs). Our quantum simulations that include hundreds of thousands of exciton and multi-exciton states demonstrate that the complex time-dependent dynamics of these states in a closed electronic system yields a saturated MEG effect on a picosecond timescale. Including phonon relaxation confirms that efficient MEG requires the exciton--biexciton coupling time to be faster than exciton relaxation time

1974 Preliminary Report of Kentucky Small Grain Variety Trials at Bowling Green and Lexington

Each year the small grain variety trials are conducted at Princeton, Murray, Bowling Green and Lexington. In 1974, the plots at Princeton and Murray were severely infected with a complex of diseases including Barley Yellow Dwarf, Septoria glume blotch, wheat scab and an unidentified disease in the wheat. As a result of the intensity of these diseases, the data obtained from these plots was very erratic and the results were not considered to be experimentally valid. The data obtained at Bowling Green and Lexington were quite valid and representative of the general situation in Kentucky

Particle dynamics of a cartoon dune

The spatio-temporal evolution of a downsized model for a desert dune is observed experimentally in a narrow water flow channel. A particle tracking method reveals that the migration speed of the model dune is one order of magnitude smaller than that of individual grains. In particular, the erosion rate consists of comparable contributions from creeping (low energy) and saltating (high energy) particles. The saltation flow rate is slightly larger, whereas the number of saltating particles is one order of magnitude lower than that of the creeping ones. The velocity field of the saltating particles is comparable to the velocity field of the driving fluid. It can be observed that the spatial profile of the shear stress reaches its maximum value upstream of the crest, while its minimum lies at the downstream foot of the dune. The particle tracking method reveals that the deposition of entrained particles occurs primarily in the region between these two extrema of the shear stress. Moreover, it is demonstrated that the initial triangular heap evolves to a steady state with constant mass, shape, velocity, and packing fraction after one turnover time has elapsed. Within that time the mean distance between particles initially in contact reaches a value of approximately one quarter of the dune basis length

Reversal of English trend towards hospital death in dementia:a population-based study of place of death and associated individual and regional factors, 2001-2010

BACKGROUND: England has one of the highest rates of hospital death in dementia in Europe. How this has changed over time is unknown. This study aimed to analyse temporal trends in place of death in dementia over a recent ten year period. METHODS: Population-based study linking Office for National Statistics mortality data with regional variables, in England 2001–2010. Participants were adults aged over 60 with a death certificate mention of dementia. Multivariable Poisson regression was used to determine the proportion ratio (PR) for death in care home (1) and home/hospice (1) compared to hospital (0). Explanatory variables included individual factors (age, gender, marital status, underlying cause of death), and regional variables derived at area level (deprivation, care home bed provision, urbanisation). RESULTS: 388,899 deaths were included. Most people died in care homes (55.3%) or hospitals (39.6%). A pattern of increasing hospital deaths reversed in 2006, with a subsequent decrease in hospital deaths (−0.93% per year, 95% CI −1.08 to −0.79 p < 0.001), and an increase in care home deaths (0.60% per year, 95% CI 0.45 to 0.75 p < 0.001). Care home death was more likely with older age (PR 1.11, 1.10 to 1.13), and in areas with greater care home bed provision (PR 1.82, 1.79 to 1.85) and affluence (PR 1.29, 1.26 to 1.31). Few patients died at home (4.8%) or hospice (0.3%). Home/hospice death was more likely in affluent areas (PR 1.23, 1.18 to 1.29), for women (PR 1.61, 1.56 to 1.65), and for those with cancer as underlying cause of death (PR 1.84, 1.77 to 1.91), and less likely in the unmarried (PRs 0.51 to 0.66). CONCLUSIONS: Two in five people with dementia die in hospital. However, the trend towards increasing hospital deaths has reversed, and care home bed provision is key to sustain this. Home and hospice deaths are rare. Initiatives which aim to support the end of life preferences for people with dementia should be investigated