16 research outputs found
Homoclinic puzzles and chaos in a nonlinear laser model
We present a case study elaborating on the multiplicity and self-similarity
of homoclinic and heteroclinic bifurcation structures in the 2D and 3D
parameter spaces of a nonlinear laser model with a Lorenz-like chaotic
attractor. In a symbiotic approach combining the traditional parameter
continuation methods using MatCont and a newly developed technique called the
Deterministic Chaos Prospector (DCP) utilizing symbolic dynamics on fast
parallel computing hardware with graphics processing units (GPUs), we exhibit
how specific codimension-two bifurcations originate and pattern regions of
chaotic and simple dynamics in this classical model. We show detailed
computational reconstructions of key bifurcation structures such as Bykov
T-point spirals and inclination flips in 2D parameter space, as well as the
spatial organization and 3D embedding of bifurcation surfaces, parametric
saddles, and isolated closed curves (isolas).Comment: 28 pages, 23 figure
Genetic Variation for Nitrogen Use Efficiency Traits in Global Diversity Panel and Parents of Mapping Populations in Pearl Millet
Nitrogen (N) is one of the primary macronutrients required for crop growth and yield.
This nutrient is especially limiting in the dry and low fertility soils where pearl millet
[Pennisetum glaucum (L.) R. Br] is typically grown. Globally, pearl millet is the sixth most
important cereal grown by subsistence farmers in the arid and semi-arid regions of
sub-Saharan Africa and the Indian subcontinent. Most of these agro-ecologies have
low N in the root zone soil strata. Therefore, there is an immense need to identify lines
that use nitrogen efficiently. A set of 380 diverse pearl millet lines consisting of a global
diversity panel (345), parents of mapping populations (20), and standard checks (15)
were evaluated in an alpha-lattice design with two replications, 25 blocks, a three-row
plot for 11 nitrogen use efficiency (NUE) related traits across three growing seasons
(Summer 2017, Rainy 2017, and Summer 2018) in an N-depleted precision field under
three different N levels (0%-N0, 50%-N50, 100%-N100 of recommended N, i.e., 100 kg
h
Deep sequencing of small RNAs reveals ribosomal origin of microRNAs in Oryza sativa and their regulatory role in high temperature
MicroRNAs are small noncoding regulatory RNAs which control gene expression by mRNA degradation or translational repression. They are significant molecular players regulating important biological processes such as developmental timing and stress response. We report here the discovery of miRNAs derived from ribosomal DNA using the small RNA datasets of 16 deep sequencing libraries of rice. Twelve putative miRNAs were identified based on highly stringent criteria of novel miRNA prediction. Surprisingly, 10 putative miRNAs (mi_7403, mi_8435, mi_12675, mi_4266, mi_4758, mi_4218, mi_8200, mi_4644, mi_14291, mi_16235) originated from rDNA of rice chromosome 9. Expression analysis of putative miRNAs and their target genes in heat tolerant and susceptible rice cultivars in control and high temperature treated seedlings revealed differential regulation of rDNA derived miRNAs. This is the first report of rDNA derived miRNAs in rice which indicates their role in gene regulation during high temperature stress in plants. Further studies in this area will open new research challenges and opportunities to broaden our knowledge on gene regulation mechanisms
Prehospital transdermal glyceryl trinitrate in patients with ultra-acute presumed stroke (RIGHT-2): an ambulance-based, randomised, sham-controlled, blinded, phase 3 trial
Background
High blood pressure is common in acute stroke and is a predictor of poor outcome; however, large trials of lowering blood pressure have given variable results, and the management of high blood pressure in ultra-acute stroke remains unclear. We investigated whether transdermal glyceryl trinitrate (GTN; also known as nitroglycerin), a nitric oxide donor, might improve outcome when administered very early after stroke onset.
Methods
We did a multicentre, paramedic-delivered, ambulance-based, prospective, randomised, sham-controlled, blinded-endpoint, phase 3 trial in adults with presumed stroke within 4 h of onset, face-arm-speech-time score of 2 or 3, and systolic blood pressure 120 mm Hg or higher. Participants were randomly assigned (1:1) to receive transdermal GTN (5 mg once daily for 4 days; the GTN group) or a similar sham dressing (the sham group) in UK based ambulances by paramedics, with treatment continued in hospital. Paramedics were unmasked to treatment,
whereas participants were masked. The primary outcome was the 7-level modified Rankin Scale (mRS; a measure of functional outcome) at 90 days, assessed by central telephone follow-up with masking to treatment. Analysis was hierarchical, first in participants with a confirmed stroke or transient ischaemic attack (cohort 1), and then in all participants who were randomly assigned (intention to treat, cohort 2) according to the statistical analysis plan. This trial is registered with ISRCTN, number ISRCTN26986053.
Findings
Between Oct 22, 2015, and May 23, 2018, 516 paramedics from eight UK ambulance services recruited 1149 participants (n=568 in the GTN group, n=581 in the sham group). The median time to randomisation was 71 min (IQR 45ā116). 597 (52%) patients had ischaemic stroke, 145 (13%) had intracerebral haemorrhage, 109 (9%) had transient ischaemic attack, and 297 (26%) had a non-stroke mimic at the final diagnosis of the index event. In the GTN group, participantsā systolic blood pressure was lowered by 5Ā·8 mm Hg compared with the sham group (p<0Ā·0001), and diastolic blood pressure was lowered by 2Ā·6 mm Hg (p=0Ā·0026) at hospital admission. We found no difference in mRS between the groups in participants with a final diagnosis of stroke or transient ischaemic stroke (cohort 1): 3 (IQR 2ā5; n=420) in the GTN group versus 3 (2ā5; n=408) in the sham group, adjusted common odds ratio for poor outcome 1Ā·25 (95% CI 0Ā·97ā1Ā·60; p=0Ā·083); we also found no difference in mRS between all patients (cohort 2: 3 [2ā5]; n=544, in the GTN group vs 3 [2ā5]; n=558, in the sham group; 1Ā·04 [0Ā·84ā1Ā·29]; p=0Ā·69). We found no difference in secondary outcomes, death (treatment-related deaths: 36 in the GTN group vs 23 in the sham group [p=0Ā·091]), or serious adverse events (188 in the GTN group vs 170 in the sham group [p=0Ā·16]) between treatment groups.
Interpretation
Prehospital treatment with transdermal GTN does not seem to improve functional outcome in patients with presumed stroke. It is feasible for UK paramedics to obtain consent and treat patients with stroke in the ultraacute prehospital setting.
Funding British Heart Foundation
2D Node-Based Finite Element Method on Linear Accelerator Cavity for Radiation Therapy
This paper deals with the Electromagnetic (EM) field characterization of an S-band Linear Accelerator (LA) Cavity, which is extensively used in cancer treatment. The analysis of the proposed cavity is carried out using an Eigen-mode full-wave EM solver. Mathematical formulation of cavity parameters using the Finite Element Method up to the system of equations is presented. The EM formulization uses a simple 2D square box as segmentation element and also node-based basis functions are used inside the cavity than the edge-based functions. The proposed numerical analysis of a single cavity of LA system is also applicable for a system with multiple numbers of cavities. The cavity has a resonance of 3.0474 GHz and a Q-factor of 17181.6 with finite conducting boundaries at the ends of the drift tube. The nose cone structure in the cavity is essential to have a stronger E-field at the center where the beam passes. Further, the particle acceleration is not constant along the axis of the cavity, which may have severe consequences for beam dynamics. Proper beam dynamics in LA plays a key role in reducing the mortality rate in cancer therapy applications
Not Available
Not AvailableMicroRNAs are small noncoding regulatory RNAs which control gene expression by mRNA degradation or
translational repression. They are signiļ¬cant molecular players regulating important biological processes such as
developmental timing and stress response. We report here the discovery of miRNAs derived from ribosomal DNA
using the small RNA datasets of 16 deep sequencing libraries of rice. Twelve putative miRNAs were identiļ¬ed
based on highly stringent criteria of novel miRNA prediction. Surprisingly, 10 putative miRNAs (mi_7403,
mi_8435, mi_12675, mi_4266, mi_4758, mi_4218, mi_8200, mi_4644, mi_14291, mi_16235) originated from
rDNA of rice chromosome 9. Expression analysis of putative miRNAs and their target genes in heat tolerant and
susceptible rice cultivars in control and high temperature treated seedlings revealed diļ¬erential regulation of
rDNA derived miRNAs. This is the ļ¬rst report of rDNA derived miRNAs in rice which indicates their role in gene
regulation during high temperature stress in plants. Further studies in this area will open new research challenges
and opportunities to broaden our knowledge on gene regulation mechanisms.Not Availabl
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Click-particle display for base-modified aptamer discovery
Base-modified aptamers that incorporate non-natural chemical moieties can achieve greatly improved affinity and specificity relative to natural DNA or RNA aptamers. However, conventional methods for generating base-modified aptamers require considerable expertise and resources. In this work, we have accelerated and generalized the process of generating base-modified aptamers by combining a click-chemistry strategy with a fluorescence-activated cell sorting (FACS)-based screening methodology that measures the affinity and specificity of individual aptamers at a throughput of ā¼10 per hour. Our "click-particle display (PD)" strategy offers many advantages. First, almost any chemical modification can be introduced with a commercially available polymerase. Second, click-PD can screen vast numbers of individual aptamers on the basis of quantitative on- and off-target binding measurements to simultaneously achieve high affinity and specificity. Finally, the increasing availability of FACS instrumentation in academia and industry allows for easy adoption of click-PD in a broader scientific community. Using click-PD, we generated a boronic acid-modified aptamer with ā¼1 Ī¼M affinity for epinephrine, a target for which no aptamer has been reported to date. We subsequently generated a mannose-modified aptamer with nanomolar affinity for the lectin concanavalin A (Con A). The strong affinity of both aptamers is fundamentally dependent upon the presence of chemical modifications, and we show that their removal essentially eliminates aptamer binding. Importantly, our Con A aptamer exhibited exceptional specificity, with minimal binding to other structurally similar lectins. Finally, we show that our aptamer has remarkable biological activity. Indeed, this aptamer is the most potent inhibitor of Con A-mediated hemagglutination reported to date