1,216 research outputs found
Activation of pluripotency genes in human fibroblast cells by a novel mRNA based approach
Background: Several methods have been used to induce somatic cells to re-enter the pluripotent state. Viral transduction of reprogramming genes yields higher efficiency but involves random insertions of viral sequences into the human genome. Although induced pluripotent stem (iPS) cells can be obtained with the removable PiggyBac transposon system or an episomal system, both approaches still use DNA constructs so that resulting cell lines need to be thoroughly analyzed to confirm they are free of harmful genetic modification. Thus a method to change cell fate without using DNA will be very useful in regenerative medicine.
Methodology/Principal Findings: In this study, we synthesized mRNAs encoding OCT4, SOX2, cMYC, KLF4 and SV40 large T (LT) and electroporated them into human fibroblast cells. Upon transfection, fibroblasts expressed these factors at levels comparable to, or higher than those in human embryonic stem (ES) cells. Ectopically expressed OCT4 localized to the cell nucleus within 4 hours after mRNA introduction. Transfecting fibroblasts with a mixture of mRNAs encoding all five factors significantly increased the expression of endogenous OCT4, NANOG, DNMT3 beta, REX1 and SALL4. When such transfected fibroblasts were also exposed to several small molecules (valproic acid, BIX01294 and 5'-aza-2'-deoxycytidine) and cultured in human embryonic stem cell (ES) medium they formed small aggregates positive for alkaline phosphatase activity and OCT4 protein within 30 days.
Conclusion/Significance: Our results demonstrate that mRNA transfection can be a useful approach to precisely control the protein expression level and short-term expression of reprogramming factors is sufficient to activate pluripotency genes in differentiated cells
INSTRUMENTED START BLOCKS: A QUANTITATIVE COACHING AID
To effect improvement in a skill such as the block start in sprinting, immediate quantitative feedback pertaining to the forces generated during the start is invaluable to both the coach and athlete. The purpose of the present study was to design a set of instrumented starting blocks, appropriate for use in the field, which would provide immediate feedback pertaining to the kinetics of a block start. Design considerations included: resolution of orthogonal force components for right and left foot pedals independently; adjustability to enable and athlete's normal foot and block placement; and adhering to standard international starting block design specifications in terms of dimensions and rigidity. The starting blocks consisted of two standard adjustable stadium starting block pedals suspended clear of the ground via two instrumented axles. The mild steel rod axles were milled to dimensions which allowed the axles to deflect minimally under expected loads. Each axle was attached laterally (and directed medially) from a 230 mm wide mild steel parallel flange channel. This base plate was firmly affixed to the synthetic track surface by six 12 mm commercial shoe spikes. Eight 3 mm student strain gauges were adhered to each axle with 4 gauges aligned to each orthogonal axis. The gauges were incorporated into a Wheatstone Bridge circuitry and arranged to measure the shear force on the axle by utilising the bending moment difference method. Using this bending moment difference method, the magnitude of the force signal recorded was unaffected by the position of force application across the block pedal. Each of the 4 orthogonal channels contained a separate amplifier to magnify the differential signal from the gauges. Calibration was accomplished via static loading of each axle in the orthogonal plane with known loads. The differential signal developed from the strain gauge circuitry under load was amplified and sampled (1000 Hz) by a personal computer using a WIN 30-D A-D converter card. From this data useful variables such as maximum horizontal and vertical force, impulse, block time, block velocity and block acceleration were quantified using custom software and were immediately available to the athlete and coach. Analysis of data obtained from the blocks for state level, national level and the current male 100 m world champion indicated the instrumented blocks were able to provide immediate relevant kinetic data for use by sprint coaches in the field
Auroral Cluster: A Space Physics Mission for Multiple, Electronically Tethered Small Satellites
Auroral Cluster is a space physics mission that has been identified by the NASA Space Physics Strategic Implementation Study as a candidate for flight in the next decade. Auroral Cluster will employ multiple spacecraft outfitted with similar complements of science instruments allowing simultaneous multipoint plasma measurements in the Earth\u27s auroral regions. Co-orbiting small satellites (mass \u3c 400 kg each) that are electronically tethered to share distributed spacecraft systems represent an efficient approach for achieving the science goals of the Auroral Cluster mission. Multisatellite missions represent a new trend in gathering space science data and pose many new and difficult challenges for the space systems engineer. The results of an Auroral Cluster feasibility study, which discusses a variety of mission trade-offs, are presented. A discussion of the science background and mission goals is used to identify the technical drivers for the design of the multiple spacecraft system. A mission plan and some considerations for a Auroral Cluster satellite design are presented. Special consideration is given to the spacecraft subsystems that will allow the system to be operated as a network of electronically tethered interdependent small satellites. These subsystems include attitude determination, spatial separation knowledge and control, data storage, and intersatellite communication
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Effect of CST ion exchange loading on the volume of glass produced during the vitrification demonstration at SRTC
ORNL and SRTC have a joint project in which 25,000 gallons of supernate waste from the Melton Valley Storage Tanks at Oak Ridge will be treated by passage through a crystalline silicotitanate (CST) ion exchange medium. The CST was designed to sorb cesium, the primary radionuclide (Cs-137) in the supernate of the Melton Valley tanks. A smaller amount of strontium will also be sorbed. At least one drum of the loaded sorbent will then be shipped to SRTC where it will be mixed with glass formers and fed as an aqueous slurry to an 1,150 C joule-heated melter within the SRTC Shielded Cells. The molten glass will be poured into 500 ml stainless steel beakers. The original plan was to place the 500 ml beakers in 30 gallon drums for shipment to and disposal at the Nevada Test Site (NTS). A recent scope change included provisions to dispose of the vitrified waste at SRS. This report addresses requirements for disposal at either NTS or SRS. Current efforts in formulation experimentation will define the CST loading for the demonstration. The glass waste form must meet durability requirements, RCRA metal release limits, and viscosity. Liquidus, and redox requirements for processing. As indicated, higher waste loadings will reduce the processing time required, thus, reducing the overall costs. An added benefit, of course, is the reduction of total waste volume provided by higher loadings, leading to less waste disposal
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Compliance with the Nevada Test Site`s waste acceptance criteria for vitrified cesium-loaded crystalline silicotitanates
As part of a joint project between the Oak Ridge National Laboratory (ORNL) and the Savannah River Technology Center (SRTC), Cs-137 loaded crystalline silicotitanate (CST) sorbent will be vitrified in a joule-heated melter. Glass formulation development for this CST sorbent is discussed in an accompanying abstract for this conference. One of the objectives for this project was to ensure that the vitrified waste form could be disposed of at the Nevada Test Site (NTS). To accomplish this objective, the waste form must meet the NTS Waste Acceptance Criteria (WAC). This paper presents SRTC`s efforts at ensuring that the glass waste form produced as a result of vitrification of CST will meet all of the criteria of the WAC. The producer must demonstrate that the waste is neither TRU nor mixed, and that the glass has a radionuclide content which is less than the Class C limit of 4,600 Ci/m{sup 3}. The impact of this requirement on the CST loading in the glass is discussed along with the benefits to the producer which result if greater than Class C waste is accepted by NTS since this limit may be relaxed in the near future. This paper demonstrates that vitrification leads to a waste form which meets all of the criteria of the NTS WAC
In-situ velocity imaging of ultracold atoms using slow--light
The optical response of a moving medium suitably driven into a slow-light
propagation regime strongly depends on its velocity. This effect can be used to
devise a novel scheme for imaging ultraslow velocity fields. The scheme turns
out to be particularly amenable to study in-situ the dynamics of collective and
topological excitations of a trapped Bose-Einstein condensate. We illustrate
the advantages of using slow-light imaging specifically for sloshing
oscillations and bent vortices in a stirred condensate
Assessment of Discordance Between Physicians and Family Members Regarding Prognosis in Patients With Severe Acute Brain Injury.
Shared decision-making requires key stakeholders to align in perceptions of prognosis and likely treatment outcomes.
For patients with severe acute brain injury, the objective of this study was to better understand prognosis discordance between physicians and families by determining prevalence and associated factors.
This mixed-methods cross-sectional study analyzed a cohort collected from January 4, 2018, to July 22, 2020. This study was conducted in the medical and cardiac intensive care units of a single neuroscience center. Participants included families, physicians, and nurses of patients admitted with severe acute brain injury.
Severe acute brain injury was defined as stroke, traumatic brain injury, or hypoxic ischemic encephalopathy with a Glasgow Coma Scale score less than or equal to 12 points after hospital day 2.
Prognosis discordance was defined as a 20% or greater difference between family and physician prognosis predictions; misunderstanding was defined as a 20% or greater difference between physician prediction and the family's estimate of physician prediction; and optimistic belief difference was defined as any difference (>0%) between family prediction and their estimate of physician prediction. Logistic regression was used to identify associations with discordance. Optimistic belief differences were analyzed as a subgroup of prognosis discordance.
Among 222 enrolled patients, prognostic predictions were available for 193 patients (mean [SD] age, 57 [19] years; 106 men [55%]). Prognosis discordance occurred for 118 patients (61%) and was significantly more common among families who identified with minoritized racial groups compared with White families (odds ratio [OR], 3.14; CI, 1.40-7.07, P = .006); among siblings (OR, 4.93; 95% CI, 1.35-17.93, P = .02) and adult children (OR, 2.43; 95% CI, 1.10-5.37; P = .03) compared with spouses; and when nurses perceived family understanding as poor compared with good (OR, 3.73; 95% CI, 1.88-7.40; P < .001). Misunderstanding was present for 80 of 173 patients (46%) evaluated for this type of prognosis discordance, and optimistic belief difference was present for 94 of 173 patients (54%). In qualitative analysis, faith and uncertainty emerged as themes underlying belief differences. Nurse perception of poor family understanding was significantly associated with misunderstanding (OR, 2.06; 95% CI, 1.07-3.94; P = .03), and physician perception with optimistic belief differences (OR, 2.32; 95% CI, 1.10-4.88; P = .03).
Results of this cross-sectional study suggest that for patients with severe acute brain injury, prognosis discordance between physicians and families was common. Efforts to improve communication and decision-making should aim to reduce this discordance and find ways to target both misunderstanding and optimistic belief differences
The effect of adolescent inhalant abuse on energy balance and growth
The abuse of volatile solvents such as toluene is a significant public health concern, predominantly affecting adolescents. To date, inhalant abuse research has primarily focused on the central nervous system; however, inhalants also exert effects on other organ systems and processes, including metabolic function and energy balance. Adolescent inhalant abuse is characterized by a negative energy balance phenotype, with the peak period of abuse overlapping with the adolescent growth spurt. There are multiple components within the central and peripheral regulation of energy balance that may be affected by adolescent inhalant abuse, such as impaired metabolic signaling, decreased food intake, altered dietary preferences, disrupted glucose tolerance and insulin release, reduced adiposity and skeletal density, and adrenal hypertrophy. These effects may persist into abstinence and adulthood, and the long-term consequences of inhalant-induced metabolic dysfunction are currently unknown. The signs and symptoms resulting from chronic adolescent inhalant abuse may result in a propensity for the development of adult-onset metabolic disorders such as type 2 diabetes, however, further research investigating the long-term effects of inhalant abuse upon energy balance and metabolism are needed. This review addresses several aspects of the short- and long-term effects of inhalant abuse relating to energy and metabolic processes, including energy balance, intake and expenditure; dietary preferences and glycemic control; and the dysfunction of metabolic homeostasis through altered adipose tissue, bone, and hypothalamic-pituitary-adrenal axis function.Rose Crossin, Ashleigh Qama, Zane B. Andrews, Andrew J. Lawrence, Jhodie R. Dunca
Interferometric detection of a single vortex in a dilute Bose-Einstein condensate
Using two radio frequency pulses separated in time we perform an amplitude
division interference experiment on a rubidium Bose-Einstein condensate. The
presence of a quantized vortex, which is nucleated by stirring the condensate
with a laser beam, is revealed by a dislocation in the fringe pattern.Comment: 4 pages, 4 figure
[Accepted Manuscript] A call to strengthen the global strategy against schistosomiasis and soil-transmitted helminthiasis: the time is now.
In 2001, the World Health Assembly (WHA) passed the landmark WHA 54.19 resolution for global scale-up of mass administration of anthelmintic drugs for morbidity control of schistosomiasis and soil-transmitted helminthiasis, which affect more than 1·5 billion of the world's poorest people. Since then, more than a decade of research and experience has yielded crucial knowledge on the control and elimination of these helminthiases. However, the global strategy has remained largely unchanged since the original 2001 WHA resolution and associated WHO guidelines on preventive chemotherapy. In this Personal View, we highlight recent advances that, taken together, support a call to revise the global strategy and guidelines for preventive chemotherapy and complementary interventions against schistosomiasis and soil-transmitted helminthiasis. These advances include the development of guidance that is specific to goals of morbidity control and elimination of transmission. We quantify the result of forgoing this opportunity by computing the yearly disease burden, mortality, and lost economic productivity associated with maintaining the status quo. Without change, we estimate that the population of sub-Saharan Africa will probably lose 2·3 million disability-adjusted life-years and US$3·5 billion of economic productivity every year, which is comparable to recent acute epidemics, including the 2014 Ebola and 2015 Zika epidemics. We propose that the time is now to strengthen the global strategy to address the substantial disease burden of schistosomiasis and soil-transmitted helminthiasis
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