172 research outputs found
Effect of ambient gases and soil moisture regimes on carbohydrate translocation in kidneybean plants grown in pots in Riyadh, KSA
This study designated to examine the effect of elevated gases in four localities of Riyadh City on carbohydrate for parts of kidneybean plants (Phaseolous vulgaris L.) grown in pots under two soil moisture regimes (well-watered vs. restricted water). Carbohydrate analysis results showed increases in kidneybean samples under well-watered conditions compared to restricted soil moisture. Most kidneybean samples at Embasses site exhibited higher soluble, insoluble and total carbohydrateconcentrations while the Batha site samples have lower values of these fractions. Batha site reduced the flux of carbohydrates from source to the sinks of both soil moisture regimes. This study concluded that there was a good relation between the effect of highly polluted localities and kidneybean leaves carbohydrate content and its translocation
Vortex pinning and critical current control and enhancement by magnetic structure and artificial arrays in YBa2Cu3O7-δ superconductor thin films
Superconductivity provides revolutionary solutions to practical applications, such as magnetic resonance imaging, fault current limiters, and unsurpassable sensitivity and characteristic for electronics and quantum computing, which to date are unattainable by more conventional technologies. The is still a lot can be improved in making superconductors cheaper, more reproducible and robust to enable even easier and broader paths into our everyday lives.
One of the most versatile superconductor with strong potential for many types of technologies and corresponding applications is YBa2Cu3O7-δ (YBCO), a high temperature superconductor (HTS) ceramic material. This material can be manufactured in the form of high quality single-crystalline epitaxial films, not only on small chips for electronic devices, but also on large area wafers and tapes over a hundred meters long for cellular communication filters and electric power generation, handling and transmission. They suffer, however from the relatively low degree of reproducibility of their functional characteristics, especially for devices required for electronics and quantum computation, for which highly accurate and reproducible functionalities are required. This reproducibility problem stems from the fact that YBCO has four elements in its crystal structure, which are rather difficult to grow in a perfectly ordered fashion
Application of inter simple sequence repeat (ISSR marker) to detect genotoxic effect of heavy metals on Eruca sativa (L.)
As an influence of the Mediterranean diet, Eruca sativa (rocket salad) is eaten all over the world in salads and soups. It belongs to plant order Capparales (glucosinolate-containing species) and it is from the family Brassicaceae. Predominantly, the leaves of this species is eaten raw or cooked, although flowers are also consumed. Assessment of environmental contamination on ecology (plant) at molecular and population levels is important in risk quantification and remediation study. Heavy metal toxicity in plants is to induce oxidative stress linked to oxidation of proteins and membrane lipids but also to alterations of DNA damage response. E. sativa has been investigated in our study which is ofagronomical importance and widely used in European countries. We studied three heavy metals Zn, Pb and Cd which showed a dose-dependent effect on radicle and coleoptile lengths of E. sativa. Theradicle length was more affected than the coleoptiles length under all concentration tested plant. The ranking of genotoxic potencies in all three heavy metals was in the descending order: Cd2+ > Pb2+ Zn2+.Among these heavy metals, high concentration of Cd (150 mg/l) and Pb (150 mg/l) generated mutations along with changed morphology of seedlings. The radicle and coleoptile lengths (cm) under high concentration of Cd were decreased as compared to low, medium and high  concentrations treated seedlings with Pb and Zn. 20 ISSR primers were used, of which four did not amplify, three gave single band and the rest of thirteen primers generated upto six bands (an average of 4 bands per primer). Sixteen primers exhibiting amplified products gave monomorphic; only two primers (OPC-5 and OPC-7) gave unique extra band in seedlings treated with medium and high concentrations of heavy metals Cdand Pb, respectively. The dendrogram was constructed to evaluate the genetic distance generated among the seedling treated with various heavy metals at various concentrations. The similarity matrix values were found from 42.8 to 100% and these values showed the genetic divergence among the seedlings treated with various concentrations of heavy metals
Temperature Effects on Liquid Crystal Nonlinearity
The effect of temperature variation on nonlinear refractive indices of several types of liquid crystal (LC) compounds has been reported. Five samples have been investigated: two pure components (E7, MLC 6241-000) and three mixtures are obtained by mixing the previous two in different proportions. Birefringence, the average refractive index and the temperature gradients of refractive indices of the LCs are determined. The variations in refractive indices and birefringence were fitted theoretically using the modified Vuks equation. Excellent agreement is obtained between the fitted values and experimental data. Finally, the bistability of nonlinear refractive indices with temperature of liquid crystal (LC) compounds has been studied. The bistability of liquid crystals based on temperature is clearly observed for all samples. Also, the extraordinary refractive index has larger bistability than the ordinary refractive index. The measurements are performed at 1550Â nm wavelength using wedged cell refractometer method
The Ophthalmological Consequences of Midfacial Trauma
Ocular injuries commonly occur in patients with facial fractures. A study was carried out of 363 patients presenting during a 2-year period with midfacial fractures. Patients underwent ophthalmological examination within one week of injury. The characteristics of the eye injuries sustained were related to the aetiology and type of fracture, and the sex and age of each patient. Ninety-one percent of patients sustained ocular injuries of various severities. Sixty-three percent sustained minor injuries, 16% suffered moderately severe injury and 12% experienced severe injuries. Road traffic accident was associated with the highest incidence of severe ocular disorder at 20% (9/45) followed by assaults at 11% (20/181). One third of all patients with comminuted malar fracture suffered a severe ocular disorder (9/27) whilst blow-out fracture came second at 16.7% (6/36). Fifty-six patients (15.4%) had a decrease in visual acuity and 9 (2.5%) sustained significant traumatic optic neuropathy. Decrease in visual acuity accompanied the majority of significant eye injuries. Road traffic accidents and assaults associated with alcohol abuse showed the highest incidence of major ocular dysfunction. Motility disorder was also common. Seventy-two patients (19.8%) developed diplopia which was most common following road traffic accidents (31%) and least common with simple falls (10%). Blow-out fractures of the orbit (n=36) led to double vision in 58% of cases (n=21). Eighty-two percent of patients recovered from diplopia within six months of injury, 11% recovered within 6-12 months and 7% of patients took more than one year to recover including one patient who required squint surgery for double vision. The principal risk factors for diplopia comprise road traffic accidents, blow-out fractures and comminuted malar fractures. Early surgical reconstruction with conservative management of ocular motility disorders has, in this series, resulted in very few patients having diplopia in the long term. Ocular injuries following facial trauma may be difficult to detect by the maxillofacial surgeon and may therefore be missed. Fifty-four parameters comprising maxillofacial, radiological and ophthalmic data were coded and recorded for each patient. These data were divided into predictors (the data potentially available to the maxillofacial surgeon) and outcome (the data potentially available to the ophthalmologist). Statistical methods of regression, and analysis of contingency tables, led to the identification of the principal predictors indicative of ophthalmic injury and thence to a scoring system which predicts the severity of such injuries. Impaired visual acuity was the principal predictor and when employed alone gave a sensitivity value of 80%. Pure blow-out fracture or comminuted facial fracture, double vision and amnesia, emerged as additional factors which yielded an efficient scoring system with a sensitivity of 89% and specificity of 90% for the population upon which it was based. This scoring system was tested in a pilot study upon a new population of 100 similar individuals. The sensitivity value was 94.4% and the specificity value was 89%. Only one patient, warranting ophthalmic referral, was missed by the system whilst nine were incorrectly classified as warranting referral. Defects of convergence and accommodation are common sequels of head injuries, the two functions failing usually to a commensurate degree although either may occasionally be separately deficient. A prospective evaluation of patients who have sustained midfacial trauma was carried out in order to determine the prevalence of impaired 23 convergence and accommodation and to establish the risk factors for such defects. Of 52 patients in this study, 11 suffered accommodation and/or convergence disturbances. They included 6 males (17% of the male population) and 5 females (29% of the female population) whose ages ranged from 13 to 72 years with a mean age value of 30.2 years. Nine of these 11 patients sustained their injuries due to alleged assaults (24.3% of all assaulted patients) and 2, following simple falls (25% of all fall victims). Five patients complained of diplopia at near (5/11=45.5%) and another 4 of blurred vision and/or difficulty with reading (4/11=36.4%). The remaining 2 patients were asymptomatic. Six patients were randomly selected to receive orthoptic exercises/treatment while the other five were monitored for signs of spontaneous recovery. Within six months of injury/surgery, 83% of the treated patients (n=5) and 80% of the non-treated patients (n=4) recovered to within the normal values of accommodation and convergence. No significant statistical relationship was found between the incidence of accommodation and/or convergence failure, and the cause or the type of fracture sustained. It may, however, be related to the severity of impact and the associated closed head trauma. (Abstract shortened by ProQuest.)
Molecular diagnostics and phylogenetic analysis of ‘Candidatus phytoplasma asteris’ (16SrI- Aster yellow group) infecting banana (Musa spp.)
The presence of phytoplasma in diseased banana plants exhibiting acute stunting symptoms was detected by the polymerase chain reaction using a primer set specific for the 16SrRNA gene of phytoplasma. The amplified DNA fragments of 1500 bp were cloned in pGEMT-Easy plasmid cloningvector and sequenced. The BLASTN and phylogenetic analyses revealed the infecting agents to be the closely related members of the ‘Candidatus phytoplasma asteris’ (16Sr I-Aster yellow) group
Regulation in some vital physiological attributes and antioxidative defense system in carrot (Daucus carota L.) under saline stress
Regulation of some key metabolic phenomena including antioxidative defense system involved in plant salt tolerance is of great concern. Changes in chlorophyll pigments, chlorophyll fl uorescence and leaf gas exchange characteristics, glycinebetaine and proline contents, and enzymatic and non-enzymatic antioxidants was assessed in two carrot (Daucus carota L.) cultivars, DC-4 and T-29 under saline stress in a greenhouse study. Application of different saline regimes (0, 50, 100 and 150 mM NaCl) to the growth medium considerably reduced the shoot and root fresh and dry weights, shoot and root lengths, chlorophyll b contents, leaf water potential (Ψw), leaf osmotic potential (Ψs), photosynthetic rate (A), water-use effi ciency, sub-stomatal CO2 concentration (Ci), stomatal conductance (gs), transpiration rate (E), Ci/Ca ratio, leaf and root K+ and Ca2+ contents, leaf MDA, total phenolics, total soluble proteins, and activities of CAT, SOD and POD enzymes, while a marked increase was observed in leaf turgor potential (Ψp), leaf and root Na+ and Cl- contents, leaf proline, glycinebetaine (GB), ascorbic acid (AsA) and H2O2 contents in both cultivars. Of both carrot cultivars, cultivar T-29 was relatively higher in shoot and root fresh weights, root Na+, leaf and root Ca2+, leaf proline, MDA, total phenolics, soluble proteins and activity of SOD enzyme. In contrast, cultivar DC-4 was relatively higher in leaf Ψw and Ψs, leaf K+, root Ca2+ and leaf GB as compared to those in the other cultivar. The relatively better growth of cultivar T-29 was found to be correlated with improved leaf water potential, leaf Ca2+, proline, phenolics, and activity of SOD enzyme under saline conditions
Identification of new SSR markers linked to leaf chlorophyll content, flag leaf senescence and cell membrane stability traits in wheat under water stressed condition
Segregating F4 families from the cross between drought sensitive (Yecora Rojo) and drought tolerant (Pavon 76) genotypes were made to identify SSR markers linked to leaf chlorophyll content, flag leaf senescence and cell membrane stability traits in wheat (Triticum aestivum L.) under water-stressed condition and to map quantitative trait locus (QTL) for the three physiological traits. The parents and 150 F4 families were evaluated phenotypically for drought tolerance using two irrigation treatments (2500 and 7500 m3/ha). Using 400 SSR primers tested for polymorphism in testing parental and F4 families genotypes, the results revealed that QTL for leaf chlorophyll content, flag leaf senescence and cell membrane stability traits were associated with 12, 5 and 12 SSR markers, respectively and explained phenotypic variation ranged from 6 to 42%. The SSR markers for physiological traits had genetic distances ranged from 12.5 to 25.5 cM. These SSR markers can be further used in breeding programs for drought tolerance in wheat
Mutagenic Effect of Sodium Azide on Seed Germination of Eruca sativa (L
Abs tract: Eruca sa t i v a is a very important crop of M adeterranean region, and highly us ed as s alad 3 in European countries. Sodium azide (NaN ) is a chemic a l mutagen, and widely us ed in crops to 3 improve their yield and quality traits. W e studied the effect of various concentrations of NaN ranged (1mM , 2mM , 3 mM , 4 mM and 5 mM ) on germination and seedling growth of Eruca at various time 3 intervals . The seeds treated at 5 mM of NaN , the percent germination profoundly affe c t e d o n d a ys 9 and 12 following its application for 120 min and 180 min of time intervals . The h ig h e s t and lowest % germin a t io n was found for 30 min and 180 min of time intervals, whilst seeds were treated at same 3 3 concentration of NaN . The radicle and coleoptile length were decreased as the concentration of NaN increas ed, and highly affected at concentratio n s 3 mM, 4 mM and 5 mM res pectively. M ore variation was found on radicle length than that of coleoptile leng t h a t s a me c o n centrations and at same time intervals
5-aminolevulinic acid induces regulation in growth, yield and physio-biochemical characteristics of wheat under water stress
The production of wheat crop is below average in many regions of the world which is ascribed to adverse environmental
conditions including drought stress. The present study was conducted to appraise the beneficial role of exogenouslyapplied
5-aminolevulinic acid (ALA) on growth, yield and some key physio-biochemical characteristics of two commercially
important wheat cultivars (Shafaq-06 and Uqab-2000) under well watered [100% field capacity (FC)] and water-deficit
(60 and 80% FC) conditions. Imposition of varying water regimes significantly decreased fresh and dry weights of shoots,
photosynthetic pigments (a and b), non-photochemical quenching of chlorophyll fluorescence (NPQ), quenching coefficient
for non-photochemical (N) of chlorophyll fluorescence (qN), K+ (potassium ion), Ca2+ (calcium ion) and P (phosphorus)
accumulation in shoot and root and yield-related attributes. In contrast, water deficit regimes caused improvement in
Fv/Fm (chlorophyll fluorescence measurement), coefficient of photochemical quenching (qP), proline, glycinebetaine
(GB) and hydrogen peroxide (H2O2) contents. Foliar spray of ALA at the rate of 50, 100 and 150 mg/L along with control
(no spray (NS) and/or water spray (WS)) significantly enhanced chlorophyll a and b pigments, qN, NPQ, qP, K+, Ca2+
and P accumulation in both roots and shoots, proline, GB, total phenolics and malondialdehyde (MDA) contents and
yield. The wheat Shafaq-06 was better in shoot dry weight, qN, NPQ and Fv/Fm, shoot and root K+, root Ca2+, proline,
GB accumulation and yield attributes, while Uqab-2000 was better in chlorophyll a contents, root P and MDA contents.
Overall, better growth and yield of Shafaq-06 than Uqab-2000 under water deficit regimes was found to be associated
with ALA improved leaf fluorescence (qN, NPQ and Fv/Fm), shoot and root K+, root Ca2+, proline and GB accumulation
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