219 research outputs found

    NAVEX: A space shuttle experiment with atomic clocks

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    A navigation and time transfer experiment (NAVEX) to be flown within the payload of the first German Spacelab mission D-1 is discussed. The objectives of the experiment are to synchronize distant ground stations with an accuracy of better than 10 nsec and to demonstrate one way ranging with an accuracy of better than 30 m. Spread spectrum signals are used and the related technique is tested. On board a Cs and a Rb clock is used. The relativistic effect of these clocks is about -25 microsec per day. On the ground at least two receiving stations and one transmitting-receiving station will be installed. The synchronization of the ground clocks by shuttle signals is compared to those achieved with clock transportations and with GPS measurements. A system description of this experiment is given containing details on the technical concept, the hardware and the planned data evaluation. The present state of the preparatory work is briefly reviewed

    Genome Editing for Crop Improvement – Applications in Clonally Propagated Polyploids With a Focus on Potato (Solanum tuberosum L.)

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    Genome-editing has revolutionized biology. When coupled with a recently streamlined regulatory process by the U.S. Department of Agriculture and the potential to generate transgene-free varieties, genome-editing provides a new avenue for crop improvement. For heterozygous, polyploid and vegetatively propagated crops such as cultivated potato, Solanum tuberosum Group Tuberosum L., genome-editing presents tremendous opportunities for trait improvement. In potato, traits such as improved resistance to cold-induced sweetening, processing efficiency, herbicide tolerance, modified starch quality and self-incompatibility have been targeted utilizing CRISPR/Cas9 and TALEN reagents in diploid and tetraploid clones. However, limited progress has been made in other such crops including sweetpotato, strawberry, grapes, citrus, banana etc., In this review we summarize the developments in genome-editing platforms, delivery mechanisms applicable to plants and then discuss the recent developments in regulation of genome-edited crops in the United States and The European Union. Next, we provide insight into the challenges of genome-editing in clonally propagated polyploid crops, their current status for trait improvement with future prospects focused on potato, a global food security crop

    A controlled evaluation of an enhanced self-directed behavioural family intervention for parents of children with conduct problems in rural and remote areas.

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    Few studies have examined the impact of parenting interventions for families in rural and isolated areas who have children with conduct problems, where-access to professional services can be difficult. The present investigation compared the effects of three conditions, two levels of self-directed behavioral family intervention: an enhanced self-directed program that combined a self-help program using written materials and a weekly telephone consultation (ESD), a self-help program (SD) and a waitlist control group (WL). At postintervention the ESD group reported significantly lower levels of disruptive behaviour, and lower levels of dysfunctional parenting than the SD and WL controls, and higher levels of consumer satisfaction. At 6 months follow-up the main effects for the ESD group had been maintained. The SD group continued to evidence improvement from postintervention to follow-up such that 65% of children in the ESD condition and 57% of children in the SD condition showed clinical reliable change on measures of disruptive behaviour. Implications of findings and directions for future research are discussed

    Evaluation of Methods to Assess in vivo Activity of Engineered Genome-Editing Nucleases in Protoplasts

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    Genome-editing is being implemented in increasing number of plant species using engineered sequence specific nucleases (SSNs) such as Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated systems (CRISPR/Cas9), Transcription activator like effector nucleases (TALENs), and more recently CRISPR/Cas12a. As the tissue culture and regeneration procedures to generate gene-edited events are time consuming, large-scale screening methodologies that rapidly facilitate validation of genome-editing reagents are critical. Plant protoplast cells provide a rapid platform to validate genome-editing reagents. Protoplast transfection with plasmids expressing genome-editing reagents represents an efficient and cost-effective method to screen for in vivo activity of genome-editing constructs and resulting targeted mutagenesis. In this study, we compared three existing methods for detection of editing activity, the T7 endonuclease I assay (T7EI), PCR/restriction enzyme (PCR/RE) digestion, and amplicon-sequencing, with an alternative method which involves tagging a double-stranded oligodeoxynucleotide (dsODN) into the SSN-induced double stranded break and detection of on-target activity of gene-editing reagents by PCR and agarose gel electrophoresis. To validate these methods, multiple reagents including TALENs, CRISPR/Cas9 and Cas9 variants, eCas9(1.1) (enhanced specificity) and Cas9-HF1 (high-fidelity1) were engineered for targeted mutagenesis of Acetolactate synthase1 (ALS1), 5-Enolpyruvylshikimate- 3-phosphate synthase1 (EPSPS1) and their paralogs in potato. While all methods detected editing activity, the PCR detection of dsODN integration provided the most straightforward and easiest method to assess on-target activity of the SSN as well as a method for initial qualitative evaluation of the functionality of genome-editing constructs. Quantitative data on mutagenesis frequencies obtained by amplicon-sequencing of ALS1 revealed that the mutagenesis frequency of CRISPR/Cas9 reagents is better than TALENs. Context-based choice of method for evaluation of gene-editing reagents in protoplast systems, along with advantages and limitations associated with each method, are discussed

    Incidentalomas during imaging for primary hyperparathyroidism—incidence and clinical outcomes

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    Background: Imaging for pre-operative localisation of parathyroid glands in primary hyperparathyroidism is now routine. This has led to the detection of incidental lesions (incidentalomas) in other organs, the nature of which is not well characterised. The aim of this study was to determine the incidence, characteristics and outcomes in patients who had incidental findings on parathyroid imaging. Methods: Records of patients who underwent imaging for primary hyperparathyroidism over 2 years were reviewed to identify incidental lesions detected on parathyroid imaging. Patients with persistent or renal hyperparathyroidism were excluded. Details on the management of detected incidentalomas were obtained from patient records. Results: Incidentalomas were identified in 17 of 170 patients (10 %) undergoing parathyroid imaging. Incidentalomas included thyroid (n = 11), breast (n = 3), lateral compartment of the neck (n = 1), lung (n = 1) and clavicle (n = 1). However, no disease of clinical significance needing treatment was detected on further investigation. Conclusions: Although a significant proportion of patients undergoing parathyroid imaging had incidental lesions detected, these seem to be of little clinical significance. The morbidity and cost of further interventions on these incidentalomas need to be weighed against the benefits of routine imaging in improving outcomes of first-time surgery in patients with primary hyperparathyroidism. Keywords: Parathyroid gland, Primary hyperparathyroidism, Imaging, Incidentaloma

    Use of fluorescence imaging and indocyanine green during colorectal surgery: Results of an intercontinental Delphi survey

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    BACKGROUND: Fluorescence imaging with indocyanine green is increasingly being used in colorectal surgery to assess anastomotic perfusion, and to detect sentinel lymph nodes. METHODS: In this 2-round, online, Delphi survey, 35 international experts were asked to vote on 69 statements pertaining to patient preparation and contraindications to fluorescence imaging during colorectal surgery, indications, technical aspects, potential advantages/disadvantages, and effectiveness versus limitations, and training and research. Methodological steps were adopted during survey design to minimize risk of bias. RESULTS: More than 70% consensus was reached on 60 of 69 statements, including moderate-strong consensus regarding fluorescence imaging's value assessing anastomotic perfusion and leak risk, but not on its value mapping sentinel nodes. Similarly, although consensus was reached regarding most technical aspects of its use assessing anastomoses, little consensus was achieved for lymph-node assessments. Evaluating anastomoses, experts agreed that the optimum total indocyanine green dose and timing are 5 to 10 mg and 30 to 60 seconds pre-evaluation, indocyanine green should be dosed milligram/kilogram, lines should be flushed with saline, and indocyanine green can be readministered if bright perfusion is not achieved, although how long surgeons should wait remains unknown. The only consensus achieved for lymph-node assessments was that 2 to 4 injection points are needed. Ninety-six percent and 100% consensus were reached that fluorescence imaging will increase in practice and research over the next decade, respectively. CONCLUSION: Although further research remains necessary, fluorescence imaging appears to have value assessing anastomotic perfusion, but its value for lymph-node mapping remains questionable

    Self-directed behavioral family intervention: Do therapists matter?

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    Behavioral family intervention is an effective form of intervention for the prevention and treatment of a wide range of emotional and behavioral problems in children. There is a growing need to address the accessibility of these services. This paper reviews the literature on self-directed interventions designed to help parents manage difficult child behaviors. Evidence regarding the efficacy of interventions is reviewed, and some of the difficulties associated with self-directed programs are discussed. The Self-directed Triple P and Teen Triple P-Positive Parenting Programs are highlighted as examples of efficacious and effective behavioral family interventions fitting into a larger multi-level model of family intervention. The discussion of the efficacy and effectiveness of self-directed Triple P has implications for service delivery of parenting programs
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