395 research outputs found
Concomitant ipsilateral intracapsular and extracapsular femoral neck fracture: a case report
<p>Abstract</p> <p>Introduction</p> <p>Intracapsular and extracapsular hip fractures are common amongst elderly patients but simultaneous intracapsular and extracapsular hip fractures are rare.</p> <p>Case presentation</p> <p>We present the case of an elderly woman who sustained simultaneous intracapsular and extracapsular hip fractures and describe the complications which ensued following fixation.</p> <p>Conclusion</p> <p>Concomitant ipsilateral intracapsular and extracapsular femoral neck fracture is an uncommon injury pattern. It occurs most commonly in osteoporotic patients with low energy falls. Close examination of radiographs must be made to ensure that more subtle fractures are not overlooked and the injury managed appropriately. If doubt exists on initial radiographs further imaging should be considered.</p
Engineering ligand-responsive RNA controllers in yeast through the assembly of RNase III tuning modules
The programming of cellular networks to achieve new biological functions depends on the development of genetic tools that link the presence of a molecular signal to gene-regulatory activity. Recently, a set of engineered RNA controllers was described that enabled predictable tuning of gene expression in the yeast Saccharomyces cerevisiae through directed cleavage of transcripts by an RNase III enzyme, Rnt1p. Here, we describe a strategy for building a new class of RNA sensing-actuation devices based on direct integration of RNA aptamers into a region of the Rnt1p hairpin that modulates Rnt1p cleavage rates. We demonstrate that ligand binding to the integrated aptamer domain is associated with a structural change sufficient to inhibit Rnt1p processing. Three tuning strategies based on the incorporation of different functional modules into the Rnt1p switch platform were demonstrated to optimize switch dynamics and ligand responsiveness. We further demonstrated that these tuning modules can be implemented combinatorially in a predictable manner to further improve the regulatory response properties of the switch. The modularity and tunability of the Rnt1p switch platform will allow for rapid optimization and tailoring of this gene control device, thus providing a useful tool for the design of complex genetic networks in yeast
Design principles for riboswitch function
Scientific and technological advances that enable the tuning of integrated regulatory components to match network and system requirements are critical to reliably control the function of biological systems. RNA provides a promising building block for the construction of tunable regulatory components based on its rich regulatory capacity and our current understanding of the sequence–function relationship. One prominent example of RNA-based regulatory components is riboswitches, genetic elements that mediate ligand control of gene expression through diverse regulatory mechanisms. While characterization of natural and synthetic riboswitches has revealed that riboswitch function can be modulated through sequence alteration, no quantitative frameworks exist to investigate or guide riboswitch tuning. Here, we combined mathematical modeling and experimental approaches to investigate the relationship between riboswitch function and performance. Model results demonstrated that the competition between reversible and irreversible rate constants dictates performance for different regulatory mechanisms. We also found that practical system restrictions, such as an upper limit on ligand concentration, can significantly alter the requirements for riboswitch performance, necessitating alternative tuning strategies. Previous experimental data for natural and synthetic riboswitches as well as experiments conducted in this work support model predictions. From our results, we developed a set of general design principles for synthetic riboswitches. Our results also provide a foundation from which to investigate how natural riboswitches are tuned to meet systems-level regulatory demands
Logic integration of mRNA signals by an RNAi-based molecular computer
Synthetic in vivo molecular ‘computers’ could rewire biological processes by establishing programmable, non-native pathways between molecular signals and biological responses. Multiple molecular computer prototypes have been shown to work in simple buffered solutions. Many of those prototypes were made of DNA strands and performed computations using cycles of annealing-digestion or strand displacement. We have previously introduced RNA interference (RNAi)-based computing as a way of implementing complex molecular logic in vivo. Because it also relies on nucleic acids for its operation, RNAi computing could benefit from the tools developed for DNA systems. However, these tools must be harnessed to produce bioactive components and be adapted for harsh operating environments that reflect in vivo conditions. In a step toward this goal, we report the construction and implementation of biosensors that ‘transduce’ mRNA levels into bioactive, small interfering RNA molecules via RNA strand exchange in a cell-free Drosophila embryo lysate, a step beyond simple buffered environments. We further integrate the sensors with our RNAi ‘computational’ module to evaluate two-input logic functions on mRNA concentrations. Our results show how RNA strand exchange can expand the utility of RNAi computing and point toward the possibility of using strand exchange in a native biological setting
Enhancing Quality and Impact of Early Phase Dose-Finding Clinical Trial Protocols:The SPIRIT DoseFinding Extension (SPIRIT-DEFINE) Guidance The SPIRIT-DEFINE Statement
Large-scale features of Last Interglacial climate: Results from evaluating the lig127k simulations for the Coupled Model Intercomparison Project (CMIP6)-Paleoclimate Modeling Intercomparison Project (PMIP4)
Abstract. The modeling of paleoclimate, using physically based tools, is
increasingly seen as a strong out-of-sample test of the models that are used
for the projection of future climate changes. New to the Coupled Model
Intercomparison Project (CMIP6) is the Tier 1
Last Interglacial experiment for 127 000 years ago (lig127k), designed to
address the climate responses to stronger orbital forcing than the
midHolocene experiment, using the same state-of-the-art models as for the future and
following a common experimental protocol. Here we present a first analysis
of a multi-model ensemble of 17 climate models, all of which have completed
the CMIP6 DECK (Diagnostic, Evaluation and Characterization of Klima) experiments. The equilibrium climate sensitivity (ECS) of
these models varies from 1.8 to 5.6 ∘C. The seasonal character of
the insolation anomalies results in strong summer warming over the Northern
Hemisphere continents in the lig127k ensemble as compared to the CMIP6 piControl and
much-reduced minimum sea ice in the Arctic. The multi-model results indicate
enhanced summer monsoonal precipitation in the Northern Hemisphere and
reductions in the Southern Hemisphere. These responses are greater in the
lig127k than the CMIP6 midHolocene simulations as expected from the larger insolation anomalies
at 127 than 6 ka. New synthesis for surface temperature and precipitation, targeted for 127 ka, have been developed for comparison to the multi-model ensemble. The
lig127k model ensemble and data reconstructions are in good agreement for summer
temperature anomalies over Canada, Scandinavia, and the North Atlantic and
for precipitation over the Northern Hemisphere continents. The model–data
comparisons and mismatches point to further study of the sensitivity of the
simulations to uncertainties in the boundary conditions and of the
uncertainties and sparse coverage in current proxy reconstructions. The CMIP6–Paleoclimate Modeling Intercomparison
Project (PMIP4) lig127k simulations, in combination with the proxy record, improve
our confidence in future projections of monsoons, surface temperature, and
Arctic sea ice, thus providing a key target for model evaluation and
optimization.
</jats:p
Enhancing Quality and Impact of Early Phase Dose-Finding Clinical Trial Protocols:The SPIRIT DoseFinding Extension (SPIRIT-DEFINE) Guidance The SPIRIT-DEFINE Statement
International audienc
Enhancing Reporting Quality and Impact of Early Phase Dose-Finding Clinical Trials:The CONSORT Dose-Finding Extension (CONSORT-DEFINE) Guidance The CONSORT-DEFINE Statement
Enhancing Reporting Quality and Impact of Early Phase Dose-Finding Clinical Trials:The CONSORT Dose-Finding Extension (CONSORT-DEFINE) Guidance The CONSORT-DEFINE Statement
International audienceThe CONSORT (CONsolidated Standards Of Reporting Trials) 2010 statement is the standard guideline for reporting completed randomised trials. The CONSORT Dose-finding Extension (DEFINE) extends the guidance (with 21 new items and 19 modified items) to early phase dose-finding trials with interim dose escalation or de-escalation strategies. Such trials generally focus on safety, tolerability, activity, and recommending dosing and scheduling regimens for further clinical development. These trials are often inadequately reported, hampering their informativeness and making evidence informed decisions difficult. The CONSORT-DEFINE guidance aims to develop an international, consensus driven guideline for reporting early phase dose-finding trials to promote transparency, completeness, reproducibility, and facilitate the interpretation of the results. The CONSORT-DEFINE guidance provides recommendations for essential items that should be reported in early phase dose-finding trials to promote greater clarity, reproducibility, informativeness, and usefulness of results
- …