20,485 research outputs found
Characteristics of Precession Electron Diffraction Intensities from Dynamical Simulations
Precession Electron Diffraction (PED) offers a number of advantages for
crystal structure analysis and solving unknown structures using electron
diffraction. The current article uses many-beam simulations of PED intensities,
in combination with model structures, to arrive at a better understanding of
how PED differs from standard unprecessed electron diffraction. It is shown
that precession reduces the chaotic oscillatory behavior of electron
diffraction intensities as a function of thickness. An additional
characteristic of PED which is revealed by simulations is reduced sensitivity
to structure factor phases. This is shown to be a general feature of dynami-cal
intensities collected under conditions in which patterns with multiple incident
beam orienta-tions are averaged together. A new and significantly faster method
is demonstrated for dynami-cal calculations of PED intensities, based on using
information contained in off-central columns of the scattering matrix.Comment: 20 pages, 7 Figure
Does use of touch screen computer technology improve classroom engagement in children?
Many studies have shown that the use of technology in the classroom may influence pupil
engagement. Despite the recent widespread use of tablet technology, however, very little research has
been carried out into their use in a primary school setting. We investigated the use of tablet computers,
specifically Apple’s ‘iPad’, in an upper primary school setting with regard to children’s engagement.
Cognitive, emotional and general engagement was higher in lessons based on iPads than those which
were not. There was no difference in behavioral engagement. Of particular significance was the increase
in engagement seen in boys, which resulted in their engagement levels increasing to levels comparable
to those seen in girls. These findings suggest that tablet technology has potential as a tool in the
classroom setting
Therapeutic antibodies: current state and future trends--is a paradigm change coming soon?
Antibody-based therapeutics currently enjoy unprecedented success, growth in research and revenues, and recognition of their potential. It appears that the promise of the "magic bullet" has largely been realized. There are currently 22 monoclonal antibodies (mAbs) approved by the United States Food and Drug Administration (FDA) for clinical use and hundreds are in clinical trials for treatment of various diseases including cancers, immune disorders, and infections. The revenues from the top five therapeutic antibodies (Rituxan, Remicade, Herceptin, Humira, and Avastin) nearly doubled from 11.7 billion in 2006. During the last several years major pharmaceutical companies raced to acquire antibody companies, with a recent example of MedImmune being purchased for $15.6 billion by AstraZeneca. These therapeutic and business successes reflect the major advances in antibody engineering which have resulted in the generation of safe, specific, high-affinity, and non-immunogenic antibodies during the last three decades. Currently, second and third generations of antibodies are under development, mostly to improve already existing antibody specificities. However, although the refinement of already known methodologies is certainly of great importance for potential clinical use, there are no conceptually new developments in the last decade comparable, for example, to the development of antibody libraries, phage display, domain antibodies (dAbs), and antibody humanization to name a few. A fundamental question is then whether there will be another change in the paradigm of research as happened 1-2 decades ago or the current trend of gradual improvement of already developed methodologies and therapeutic antibodies will continue. Although any prediction could prove incorrect, it appears that conceptually new methodologies are needed to overcome the fundamental problems of drug (antibody) resistance due to genetic or/and epigenetic alterations in cancer and chronic infections, as well as problems related to access to targets and complexity of biological systems. If new methodologies are not developed, it is likely that gradual saturation will occur in the pipeline of conceptually new antibody therapeutics. In this scenario we will witness an increase in combination of targets and antibodies, and further attempts to personalize targeted treatments by using appropriate biomarkers as well as to develop novel scaffolds with properties that are superior to those of the antibodies now in clinical use
SUMOylation of NaV1.2 channels mediates the early response to acute hypoxia in central neurons.
The mechanism for the earliest response of central neurons to hypoxia-an increase in voltage-gated sodium current (INa)-has been unknown. Here, we show that hypoxia activates the Small Ubiquitin-like Modifier (SUMO) pathway in rat cerebellar granule neurons (CGN) and that SUMOylation of NaV1.2 channels increases INa. The time-course for SUMOylation of single NaV1.2 channels at the cell surface and changes in INa coincide, and both are prevented by mutation of NaV1.2-Lys38 or application of a deSUMOylating enzyme. Within 40 s, hypoxia-induced linkage of SUMO1 to the channels is complete, shifting the voltage-dependence of channel activation so that depolarizing steps evoke larger sodium currents. Given the recognized role of INa in hypoxic brain damage, the SUMO pathway and NaV1.2 are identified as potential targets for neuroprotective interventions
Cost effectiveness analysis of different approaches of screening for familial hypercholesterolaemia
Objectives To assess the cost effectiveness of
strategies to screen for and treat familial
hypercholesterolaemia.
Design Cost effectiveness analysis. A care pathway for
each patient was delineated and the associated
probabilities, benefits, and costs were calculated.
Participants Simulated population aged 1654 years
in England and Wales.
Interventions Identification and treatment of patients
with familial hypercholesterolaemia by universal
screening, opportunistic screening in primary care,
screening of people admitted to hospital with
premature myocardial infarction, or tracing family
members of affected patients.
Main outcome measure Cost effectiveness calculated
as cost per life year gained (extension of life
expectancy resulting from intervention) including
estimated costs of screening and treatment.
Results Tracing of family members was the most cost
effective strategy (£3097 (&5066, $4479) per life year
gained) as 2.6 individuals need to be screened to
identify one case at a cost of £133 per case detected. If
the genetic mutation was known within the family
then the cost per life year gained (£4914) was only
slightly increased by genetic confirmation of the
diagnosis. Universal population screening was least
cost effective (£13 029 per life year gained) as 1365
individuals need to be screened at a cost of £9754 per
case detected. For each strategy it was more cost
effective to screen younger people and women.
Targeted strategies were more expensive per person
screened, but the cost per case detected was lower.
Population screening of 16 year olds only was as cost
effective as family tracing (£2777 with a clinical
confirmation).
Conclusions Screening family members of people
with familial hypercholesterolaemia is the most cost
effective option for detecting cases across the whole
population
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