1,276 research outputs found
Structural, optical and magnetic properties of nanostructured Cr-substituted Ni-Zn spinel ferrites synthesized by a microwave combustion method
Nanoparticles of Cr3+-substituted Ni-Zn ferrites with a general formula
Ni0.4Zn0.6-xCrxFe2O4 (x = 0.0 - 0.6) have been synthesized via a facile
microwave combustion route. The crystalline phase has been characterized by
XRD, TEM, FT-I and XPS revealing the spinel ferrite structure without extra
phases. Crystallite sizes of 23 - 32 nm as estimated by XRD analyses, after
corrections for crystal stains by Williamson-Hall method, are comparable to the
average particle sizes observed by TEM which indicates successfully synthesized
nanocrystals. Rietveld refinement analyses of the XRD patterns have inferred a
monotonic decrease behavior of the lattice parameter with Cr doping in
agreement with Vegard's law of solid solution series. Furthermore, cations
distribution with an increased inversion factor indicate the B-site preference
of Cr3+ ions. The oxidation states and cations distribution indicated by XPS
results imply the Cr3+ doping on the account of Zn2+ ions and a partial
reduction of Fe3+ to Fe2+ to keep the charge balance in a composition series of
(Ni2+)0.4(Zn2+, Cr3+)0.6(Fe2+, Fe3+)2(O2-)4. The optical properties were
explored by optical UV-Vis spectroscopy indicating allowed direct transitions
with band gap energy that decreases from 3.9 eV to 3.7 eV with Cr doping.
Furthermore, the photocatalytic activity for the degradation of methyl orange
(MO) dye was investigated showing largely enhanced photodecomposition up to 30%
of MO dye over Ni0.4Cr0.6Fe2O4 for 6 hours. A vibrating sample magnetometry
(VSM) measurements at room temperature show further enhancement in the
saturation magnetization of Ni0.4Zn0.6Fe2O4 , the highest in Ni-Zn ferrites,
from about 60 to 70 emu/g with the increase of Cr concentration up to x = 0.1,
while the coercivity shows a general increase in the whole range of Cr doping.Comment: 21 page, 9 figure
Effect of Vermicompost Supplemented by Foliar Application of Silicate on Marjoram Plants Grown in Saline Soil
This study aimed to reduce the negative effects of soil salinity on marjoram plants by adding vermicompost to the saline soil complemented by foliar application of silicate (Si+2) to their leaves. To achieve this purpose in field, the experiment was arranged as a factorial experiment. (Two way) Based on randomized complete block design with four replications. The first factor was vermicompost which was added at four rates (0, 3, 4 and 5 ton fed-1). The second factor was silicon which was used at four rates (0, 2.5, 3.75 and 5 mM). Results revealed that the single application of either vermicompost or silicon reduced Na and proline concentration in plant shoot and enhanced plant growth, nutrient content, carbohydrate percentage and essential oil yield in plant shoots. This increase remained constant and not correlated with the rates of application. The combined application of vermicompost and foliar spraying of silicon resulted in noticeable increase in plant growth, nutrient content (N, P, K and Ca), carbohydrate percentage and essential oil yield in marjoram plants; the highest values of all parameters were recorded by using vermicompost at rate 3 or 4-ton fed-1 coupled with spraying 3.75 mM of silicon solution on plant leaves. These results proved that amendment of saline soil by adding vermicompost and spraying silicon solution on plant leaves directly is a good strategy for the reclamation of saline soil and mitigation of salt stress within plant tissues.Â
Identifying leaf rust resistance gene Lr19 in durum wheat using simple sequence repeat (SSR) marker
Leaf rust, caused by Puccinia triticina Eriks., is an important disease affecting durum wheat (Triticum turgidum ssp. durum) worldwide, particularly in the Mediterranean region. The disease can be controlled through the use of plant host resistance. Based on seedling resistance tests of 103 durum genotypes against a bulk of P. triticina, urediniospores were previously collected from Syria and Lebanon during 2007/08 and 2008/09 growing seasons. Percentage of resistance in the durum set tested was up to 52%. The resistant genotypes might have one of the following resistance gene(s): Lr15, Lr 19, Lr 24, Lr 25, Lr 27 +31, Lr 28 and Lr 29. Results revealed that the Gb/130-bp polymorphic band was linked to Lr19 and Sr25. In this study, twelve genotypes carrying resistance to Lr19 and Sr25 have been identified (Azeghar2, Rutucha1, Ammar9/Azeghar2, Ammar9/Terbol97-4, T.polonicum9/Ch1//Icamor-TA04-68/3/Icamor-TA04-69//(Lahn/ Ch1)2519, Arislahn5//Icamor-TA04- 63/Icasyr1, T.dicoccum1/Ch1//Ammar8/3/Bonadur/Icamor-TA04-63, Mrb3/ T. urartu500651/4/Icamor- TA04-63/3/Bcr/Gro1// Mgnl1, SwAlg/Gd1-81 //Ch1-48, Icamor-TA04-1//Mgnl3/Ainzen1, 319-ADDO/5/D68-1- 93A-1A//Ruff/Fg/3/Mtl5/4/Lahn, and Mrf1/Stj2/3/1718/BT24//Karim). Promising results on Gb/130-bp and genotypes carrying Lr19 and Sr25 will be used in a marker assisted selection of the durum breeding programs in the Mediterranean region.Key words: Puccinia triticina, durum genotypes, Syria, Lebanon, Lr19, Sr25, Gb primer
Role of Kinins in Hypertension and Heart Failure
The kallikrein-kinin system (KKS) is proposed to act as a counter regulatory system against the vasopressor hormonal systems such as the renin-angiotensin system (RAS), aldosterone, and catecholamines. Evidence exists that supports the idea that the KKS is not only critical to blood pressure but may also oppose target organ damage. Kinins are generated from kininogens by tissue and plasma kallikreins. The putative role of kinins in the pathogenesis of hypertension is discussed based on human mutation cases on the KKS or rats with spontaneous mutation in the kininogen gene sequence and mouse models in which the gene expressing only one of the components of the KKS has been deleted or over-expressed. Some of the effects of kinins are mediated via activation of the B(2) and/or B(1) receptor and downstream signaling such as eicosanoids, nitric oxide (NO), endothelium-derived hyperpolarizing factor (EDHF) and/or tissue plasminogen activator (T-PA). The role of kinins in blood pressure regulation at normal or under hypertension conditions remains debatable due to contradictory reports from various laboratories. Nevertheless, published reports are consistent on the protective and mediating roles of kinins against ischemia and cardiac preconditioning; reports also demonstrate the roles of kinins in the cardiovascular protective effects of the angiotensin-converting enzyme (ACE) and angiotensin type 1 receptor blockers (ARBs)
Transgelin is a TGFβ-inducible gene that regulates osteoblastic and adipogenic differentiation of human skeletal stem cells through actin cytoskeleston organization
Regenerative medicine is a novel approach for treating conditions in which
enhanced bone regeneration is required. We identified transgelin (TAGLN), a
transforming growth factor beta (TGFβ)-inducible gene, as an upregulated gene
during in vitro osteoblastic and adipocytic differentiation of human bone
marrow-derived stromal (skeletal) stem cells (hMSC). siRNA-mediated gene
silencing of TAGLN impaired lineage differentiation into osteoblasts and
adipocytes but enhanced cell proliferation. Additional functional studies
revealed that TAGLN deficiency impaired hMSC cell motility and in vitro
transwell cell migration. On the other hand, TAGLN overexpression reduced hMSC
cell proliferation, but enhanced cell migration, osteoblastic and adipocytic
differentiation, and in vivo bone formation. In addition, deficiency or
overexpression of TAGLN in hMSC was associated with significant changes in
cellular and nuclear morphology and cytoplasmic organelle composition as
demonstrated by high content imaging and transmission electron microscopy that
revealed pronounced alterations in the distribution of the actin filament and
changes in cytoskeletal organization. Molecular signature of TAGLN-deficient
hMSC showed that several genes and genetic pathways associated with cell
differentiation, including regulation of actin cytoskeleton and focal adhesion
pathways, were downregulated. Our data demonstrate that TAGLN has a role in
generating committed progenitor cells from undifferentiated hMSC by regulating
cytoskeleton organization. Targeting TAGLN is a plausible approach to enrich
for committed hMSC cells needed for regenerative medicine application
Genotype diet interaction in Fayoumi and Rhode Island Red layers and their crosses
Fayoumi and Rhode Island Red (R.I.R.) layers and their two reciprocal crosses were distributed into 2 groups which received different diets in the laying period. The diets had the same calculated energy level and their total protein content differed by less than 1 p. 100, but one of them contained 40 p. 100 barley and the other contained none. With the barley-containing diet, feed consumption, egg mass, egg number and mean egg weight per hen were reduced, but the effects were more marked in the R.LR. line and one of the reciprocal crosses, with a significant genotype x diet interaction for egg mass, average clutch length, total feed intake and its residual component.Des poules Fayoumi et Rhode Island (R.LR.) et leurs 2 croisements réciproques ont été répartis en 2 groupes recevant un régime alimentaire différent en période de ponte. Les 2 régimes avaient la même teneur énergétique et un taux protéique différant de moins de 1 p. 100 mais l’un contenait 40 p. 100 d’orge, l’autre n’en contenait pas. En présence de la ration à base d’orge, la consommation alimentaire et la masse d’oeufs produite par poule, ainsi que le nombre et le poids moyen des oeufs, étaient abaissés, mais les effets étaient plus marqués dans la lignée R.LR. et dans l’un des croisements réciproques, avec une interaction régime x type génétique significative pour la masse d’oeufs, la longueur moyenne des séries de ponte, la consommation alimentaire totale et sa composante « résiduelle »
Locus Interactions Underlie Seed Yield In Soybeans Resistant to Heterodera glycines
In soybean (Glycine max L. Merr.) combining resistance to cyst nematode (SCN; Heterodera glycines I.) with high seed yieldremains problematic. Molecular markers linked to quantitative trait loci (QTL) have not provided a solution. Sets of markers describing a collection of favorable alleles (linkats) may assist plant breeders seeking to combine both traits. The objective of this analysis was to identify linkats in genomic regions underlying seed yield and root SCN resistance QTL. Used were groups of cultivars selected from a single recombinant inbred (RIL) population derived from \u27Essex\u27 by \u27Forrest\u27 (ExF). The yield was measured at four locations. SCN resistance was determined in greenhouse assays. The mean seed yield was used to define 3 groups (each n = 30), high, medium and low. SCN resistance formed 2 groups (SCN resistant (n = 21) and SCN susceptible (n = 69)). Microsatellite markers (213) alleles were compared with seed yield and root SCN (Hetrodera glycines) resistance using mean analysis. The number, size and position of potential linkats were determined. Loci, genomic regions and linkats associated with seed yield were identified on linkage group (LG) K and with root resistance to SCN e on LG E, G, and D1b+W. A method to identify co-localized genomic regions is presented
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