304 research outputs found

    The Effect of 2, 4-Dichlorophenoxy Acetic Acid (2, 4-D) Concentration on Callus Induction in Sugarcane (Saccharum officinarum)

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    Experiment was designed and conducted to determine the most appropriate concentration of 2, 4-Dichlorophenoxy Acetic Acid suitable for callus induction in sugarcane. Explants were obtained from apical meristems of two sugarcane cultivars (SP726180 and CO-001) and cultured in a modified MS medium supplemented with varying concentrations of 2,4-D. After sterilization, the explants were incubated in the growth chamber at 270C and monitored for callus induction for four Weeks. The resulting calli were sub cultured on a media with a reduced 2,4-D concentration to induce somatic embryogenesis. Percentages of callus formation, embryogenic callus as well as growth coefficient were the parameters monitored. Data generated were analyzed using Chi-square and showed a significant difference among the different 2,4-D concentrations (P≤0.05). Swelling of the explants was observed one week after inoculation while callus initiation begun after two weeks. The calli were found to be yellowish, compact and nodular. Callus induction was found to increase with increase in the concentration of 2,4-D.Keywords: Saccharum officinarum, Explants, Callus Induction, 2,4-Dichlorophenoxy Acetic AcidNigerian Journal of Basic and Applied Science (2011), 19 (2): 213-21

    Micro propagation of wormwood ( Artemisia annua l.) using leaf primordia

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    A study was carried out to determine the effect of varying concentrations of some plant growth hormones on the in vitro propagation of Artemisiaannua from leaf primordial in the Biotechnology Laboratory of Plant Science Department of Ahmadu Bello University, Zaria. Leaf primordial from aChinyong variety were sterilized, excised and inoculated on a full and half strengths Murashige & Skoog basal media supplemented with differentconcentrations of GA3, BAP and NAA. Highest regeneration percent was observed using full strength MS media supplemented with a combination of 1.5µm/l GA3 and 0.5µm/l BAP. However, a combination of 0.5µm/l GA3  and 0.5µm/l NAA had the fewer days to regeneration. Highest height wasobserved at 1.0µm/l GA3 and 0.5µm/l BAP. Similarly, 2.0µm/l GA3 and 0.5µm/l BAP followed by 0.5µm/l GA3 and 0.1µm/l BAP produced the best vigor with no response from half strength MS media. Results of Analysis of Variance indicated significant difference among the treatments compared  with the control which did not respond (P.0.05). Regeneration of Artemisia through leaf primordial provides a biomass of leaf material needed for Artemisinin production. Therefore, this is a viable approach to the supply ofthe raw materials needed for the production of anti malaria drugs for the fight against malaria fever.Key Words: Artemisia annua, Plant growth hormones, in vitro propagation, leaf primordia

    Effect of Varying Concentrations of Auxin (2,4-D) on In vitro Callus Initiation Using Leaf of Artemisia annua (L)

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    Study was carried out to determine the effect of varying concentrations of auxin on callus initiation using the leaves Artemisia annua as explants which were sterilized and inoculated into Murashig and Skoog basal medium supplemented with varying concentrations of 2,4-Dichlorophenoxy acetic acid (2,4-D) and incubated in the growth chamber for 4 weeks at 27ºc. Best results were obtained with 1.0 μm/l and 1.5 μm/l concentrations. Analysis of variance (ANOVA) indicated significant difference among all the treatments (P<0.05) on the parameters studied compared with the control. Consequently, 1.0 μm/l and 1.5 μm/l concentrations of 2,4-D are ideal for callus initiation in A. annua. This provides the means to mass propagation of A. annua through callus initiation and subsequent provision of raw materials required for artemisinin extraction.Keywords: Artemisia annua, Callus, Auxin, In vitro, 2,4- Dichlorophenoxy acetic acid (2,4-D

    Inheritance of fresh seed dormancy in Spanish-type peanut (Arachis hypogaea L.): bias introduced by inadvertent selfed flowers as revealed by microsatellite markers control

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    Production and seed quality in peanut (Arachis hypogaea L.) can be reduced substantially by in situ germination under unpredictable rainfed environments. Inheritance of fresh seed dormancy in Spanish x Spanish crosses was studied with two sets of segregating populations, an F2 population derived from true F1 hybrids identified with peanut microsatellites markers and other populations (F2, BC1P1S and BC1P2S) from randomly-selected F1 individuals. In the F2 population developed with true F1 hybrids, the chi square test was not significant for the deviation from the expected 3:1 (dormant: non-dormant) ratio. In addition, the bimodal frequency distribution curve with the F2 population gave more evidence that fresh seed dormancy is controlled by a single dominant gene. The average frequency (48%) of true F1 hybrids give evidence that deviations from expected ratios in the populations (F2 and BC1P1S) developed from non-tested F1 individuals, is most likely due to inadvertent selfs. This study emphasized the need to identify with molecular markers the cross progenies in self-pollinated crops as peanutbefore testing for any trait

    Transcatheter and surgical intervention for secondary mitral regurgitation

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    Objectives: This is a protocol for a Cochrane Review (intervention). The objectives are as follows:. To assess the effects in secondary mitral regurgitation of:. Surgical mitral valve intervention and coronary artery bypass graft versus coronary artery bypass graft alone; and Transcatheter mitral valve intervention and medical therapy versus medical therapy alone

    Seizure and cognitive outcomes after resection of glioneuronal tumors in children

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    Objective: Glioneuronal tumors (GNTs) are well‐recognized causes of chronic drug‐resistant focal epilepsy in children. Our practice involves an initial period of radiological surveillance and antiepileptic medications, with surgery being reserved for those with radiological progression or refractory seizures. We planned to analyze the group of patients with low‐grade GNTs, aiming to identify factors affecting seizure and cognitive outcomes. / Methods: We retrospectively reviewed the medical records of 150 children presenting to Great Ormond Street Hospital with seizures secondary to GNTs. Analysis of clinical, neuroimaging, neuropsychological, and surgical factors was performed to determine predictors of outcome. Seizure outcome at final follow‐up was classified as either seizure‐free (group A) or not seizure‐free (group B) for patients with at least 12‐months follow‐up postsurgery. Full‐scale intelligence quotient (FSIQ) was used as a measure of cognitive outcome. / Results: Eighty‐six males and 64 females were identified. Median presurgical FSIQ was 81. One hundred twenty‐one patients (80.5%) underwent surgery. Median follow‐up after surgery was 2 years, with 92 patients (76%) having at least 12 months of follow‐up after surgery. Seventy‐four patients (80%) were seizure‐free, and 18 (20%) continued to have seizures. Radiologically demonstrated complete tumor resection was associated with higher rates of seizure freedom (P = .026). Higher presurgical FSIQ was related to shorter epilepsy duration until surgery (P = .012) and to older age at seizure onset (P = .043). / Significance: A high proportion of children who present with epilepsy and GNTs go on to have surgical tumor resection with excellent postoperative seizure control. Complete resection is associated with a higher chance of seizure freedom. Higher presurgical cognitive functioning is associated with shorter duration of epilepsy prior to surgery and with older age at seizure onset. Given the high rate of eventual surgery, early surgical intervention should be considered in children with continuing seizures associated with GNTs

    A Review of Supercapacitors: Materials Design, Modification, and Applications

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    This is the final version. Available on open access from MDPI via the DOI in this recordSupercapacitors (SCs) have received much interest due to their enhanced electrochemical performance, superior cycling life, excellent specific power, and fast charging–discharging rate. The energy density of SCs is comparable to batteries; however, their power density and cyclability are higher by several orders of magnitude relative to batteries, making them a flexible and compromis-ing energy storage alternative, provided a proper design and efficient materials are used. This review emphasizes various types of SCs, such as electrochemical double-layer capacitors, hybrid su-percapacitors, and pseudo-supercapacitors. Furthermore, various synthesis strategies, including sol-gel, electro-polymerization, hydrothermal, co-precipitation, chemical vapor deposition, direct coating, vacuum filtration, de-alloying, microwave auxiliary, in situ polymerization, electro-spin-ning, silar, carbonization, dipping, and drying methods, are discussed. Furthermore, various func-tionalizations of SC electrode materials are summarized. In addition to their potential applications, brief insights into the recent advances and associated problems are provided, along with conclu-sions. This review is a noteworthy addition because of its simplicity and conciseness with regard to SCs, which can be helpful for researchers who are not directly involved in electrochemical energy storage.Saudi Aramco Chair ProgrammeEngineering and Physical Sciences Research Council (EPSRC

    Surface Plasmon Resonance Sensing Detection of Mercury and Lead Ions Based on Conducting Polymer Composite

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    A new sensing area for a sensor based on surface plasmon resonance (SPR) was fabricated to detect trace amounts of mercury and lead ions. The gold surface used for SPR measurements were modified with polypyrrole-chitosan (PPy-CHI) conducting polymer composite. The polymer layer was deposited on the gold surface by electrodeposition. This optical sensor was used for monitoring toxic metal ions with and without sensitivity enhancement by chitosan in water samples. The higher amounts of resonance angle unit (ΔRU) were obtained for PPy-CHI film due to a specific binding of chitosan with Pb2+ and Hg2+ ions. The Pb2+ ion bind to the polymer films most strongly, and the sensor was more sensitive to Pb2+ compared to Hg2+. The concentrations of ions in the parts per million range produced the changes in the SPR angle minimum in the region of 0.03 to 0.07. Data analysis was done by Matlab software using Fresnel formula for multilayer system

    Hidden magnetic excitation in the pseudogap phase of a model cuprate superconductor

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    The elucidation of the pseudogap phenomenon of the cuprates, a set of anomalous physical properties below the characteristic temperature T* and above the superconducting transition temperature Tc, has been a major challenge in condensed matter physics for the past two decades. Following initial indications of broken time-reversal symmetry in photoemission experiments, recent polarized neutron diffraction work demonstrated the universal existence of an unusual magnetic order below T*. These findings have the profound implication that the pseudogap regime constitutes a genuine new phase of matter rather than a mere crossover phenomenon. They are furthermore consistent with a particular type of order involving circulating orbital currents, and with the notion that the phase diagram is controlled by a quantum critical point. Here we report inelastic neutron scattering results for HgBa2CuO4+x (Hg1201) that reveal a fundamental collective magnetic mode associated with the unusual order, and that further support this picture. The mode's intensity rises below the same temperature T* and its dispersion is weak, as expected for an Ising-like order parameter. Its energy of 52-56 meV and its enormous integrated spectral weight render it a new candidate for the hitherto unexplained ubiquitous electron-boson coupling features observed in spectroscopic studies.Comment: 8 pages, 3 figures, with supplementary information and figure

    Fluoride content and recharge ability of five glassionomer dental materials

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    <p>Abstract</p> <p>Background</p> <p>The relationship between fluoride content and fluoride release for glass-ionomer cements is not well understood. The aim of this laboratory study was: to determine the fluoride concentrations at the surfaces of glass-ionomer materials with respect to different storage media and different pH environments; to examine the recharge ability of the materials after NaF immersion; and to assess the morphological changes at the material surfaces using scanning electron microscope and energy dispersive spectroscopic techniques (SEM/EDS).</p> <p>Methods</p> <p>Five glass-ionomer materials, Fuji Triage (FT), Fuji II LC (FII), Fuji VIII (FVIII), Fuji IX GP (FIX), and Ketac N100 (KN), were analyzed in this study. Resin-based fluoride releasing material Helioseal F (HSF) was used as a comparison material. The sample consisted of 120 cured cement disks (n = 20 disks of each tested material, 10 × 1.5 mm). Five disks of each material were stored in 4 different storage media (I- saline, II- acidic solution ph = 2.5, III- acid solution ph = 5.5, IV- NaF solution (c = 500/106). After 7 days, two disks of each material were transferred from media I, II and III to the NaF solution for 3 min. EDS analysis was conducted in 3 randomly selected spots of each experimental disk. SEM was used to determine morphological characteristics of the material surface. Differences between the experimental groups have been analyzed using Student's t-test with the level of significance set at p < 0.001.</p> <p>Results</p> <p>FT showed the highest fluoride content at the surface of the material. The lowest amounts of fluoride ions were detected at the surfaces of the FT disks stored at low pH environments, and this difference was statistically significant (p < 0.001). Glass-ionomers showed significantly higher fluoride concentrations when compared to the HSF (p < 0.001). After immersion in the NaF solution, fluoride concentrations at the surfaces of the disks increased when compared with previous storage media (FT>FVIII>KN>FII>FIX). SEM analysis of the surface morphology revealed numerous voids, cracks and microporosities in all experimental groups, except for KN and HSF. More homogenous material structure with more discrete cracks was observed in samples stored at neutral pH environment, compared to disks stored in acidic solutions.</p> <p>Conclusion</p> <p>The tested materials could be considered as promising dental materials with potential prophylactic characteristics due to their relatively high fluoride content, but also the ability to extensively reabsorb fluoride ions, especially in acidic environments.</p
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