1,991 research outputs found
Effects of Drought Stress on Photosynthesis Factors in Wheat Genotypes during Anthesis
Drought is one of most important environmental factors inhibiting photosynthesis and decreasing growth and productivity of plants. The sensitivity of crop plants such as wheat to soil drought is particularly serious during reproductive phase is extremely sensitive to plant water status. The aim of this work was to study the effects of drought stress on photosynthesis, photosynthetic pigments, soluble proteins, a-tocopherol and abscisic acid content in six wheat genotypes, two tolerant (Daric and 92 Zhong), two moderately tolerant (Sabalan and DH-2049-3) and two sensitive (Shark and Teveeâsâ). Total chlorophyll content, relative water content and chlorophyll a/b ratio decreased after long-time drought stress, that decrease in sensitive genotypes was higher than others. Net photosynthesis and stomatal conductance decreased significantly (P < 0.05) in flag leaves of our genotypes under drought stress after pollination, that decrease in sensitive genotypes was higher, too. Abscisic acid content, soluble protein content and a-tocopherol increased under drought stress, that increase in tolerant genotypes was higher. There was a significant negative correlation (P < 0.05) between photosynthesis factors and abscisic acid content in flag leaves of all genotypes. It can be concluded that Daric and 92 Zhong had a better photosynthesis factors compared to other genotypes and showed a higher capacity to tolerate drought stress
Reduced Phagocytic Capacity of Blood Monocyte/Macrophages in Tuberculosis Patients Is Further Reduced by Smoking.
Tuberculosis (TB) and tobacco use are two major alarming global health issues posing immense threats to human populations. Mycobacterium tuberculosis (MTB) by activation of macrophages could induce the sequences of cells activation and releases of inflammatory cytokines such as CXCL-8, Il-12 and TNF-α which in turn induces the immune system network. However no information is available on other activity of cells by MTB and smoking. In the current study we aimed to investigate the serum levels TNF-a, CXCL-8 and phagocytosis capacity in tuberculosis patients with and without smoking. 103 subjects entered the study including 61 new diagnosed pulmonary TB patients (23 smokers and 38 nonsmokers) and 42 control healthy subjects. The phagocytosis of fluorescein isothiocyanate dextran (FITC-dextran) in blood monocytes/macrophages through flowcytometry was assessed. Serum levels of TNF-a and CXCL-8 were analyzed by ELISA methods. A lower percentage of cells from TB patients who smoked [50.29% (43.4-57.2), p<0.01] took up FITC-dextran after 2h compared to non-smoking TB subjects [71.62% (69.2-74.1)] and healthy cases [97.45% (95.9-99.1). Phagocytic capacity was inversely correlated with cigarette smoking as measured by pack years (r=-0.73, p<0.001). The serum levels of TNF-a and CXCL-8 were significantly higher in the TB patients who smoked compared to the TB non-smoker group (p<0.001, p<0.01 respectively). Blood monocytes/macrophages from TB patients have reduced phagocytic capacity which is further reduced in TB patients who smoke. Smoking enhanced serum levels of TNF-a and CXCL-8 suggesting a greater imbalance between the proinflammatory and anti-inflammatory factors in these patients
Green synthesis of silver nanoparticles (AgNPs) by Lallemantia royleana leaf Extract: Their Bio-Pharmaceutical and catalytic properties
The study of the silver nanoparticles (AgNPs) synthesis based-green methods become more interesting recently due to their low-cost preparation, eco-friendly and non-toxic precursors. The present study approved the ability of the Lallemantia royleana (Benth. in Wall.) Benth. leaf extract for the synthesis of AgNPs for the first time. The synthesized AgNPs were physico-chemical characterized using ultravioletâvisible spectroscopy (UVâVis), X-ray diffraction (XRD), Fourier Transform-Infrared Spectroscopy (FT-IR), zeta potential and transmission electron microscopy (TEM) analysis. The total phenols, flavonoids, anthocyanin, tannin contents, antioxidant, antimicrobial, anti-inflammatory, anti-arthritic and cytotoxic activities of L. royleana leaf extract and the synthesized AgNPs were investigated. The biocatalytic activity of prepared AgNPs was assessed on methylene blue as a pollutant organic dye. The TEM examination showed that the synthesized AgNPs were predominantly spherical with some mixed shapes and crystalline with average size 34.47 ± 1.6 nm, and showed a localized surface plasmon resonance (LSPR) peak at 425 nm. The zeta potential value was â24.1 mV indicating the stability of produced AgNPs. The new prepared AgNPs have lower total phenols, flavonoids, anthocyanin, tannin contents than L. royleana leaf extract. In addition, the new prepared AgNPs demonstrated the higher DPPH radical scavenging activity (87 %) and the ABTS radical scavenging activity (77 %) at the maximum prepared concentration of 250 ÎŒg mLâ1 as compared to the L. royleana leaf extract (62 % and 58 %, respectively). The produced AgNPs also exhibited the higher antimicrobial activity against both the Gram-positive (Staphylococcus aureus and Bacillus cereus) and the Gram-negative (Escherichia coli and Shigella flexneri) bacteria and the Candida strains (Candida glabrata and Candida albicans) as compared to the L. royleana leaf extract. The resulting AgNPs indicated a dose-dependent anti-inflammatory effect on human red-blood cell (RBC) membrane stabilization assay and had more activity (72 %) compared to the L. royleana leaf extract (61 %) at 250 ”g mLâ1. The prepared AgNPs showed promising in vitro anti-arthritic activity evaluated by 73 % compared to 58 % in case of L. royleana leaf extract. The new produced AgNPs showed the higher cytotoxic effect against the human hepatoma (Hep-G2) and the human breast (MCF-7) cancer cells compared to the L. royleana leaf extract with 79.3 % and 77.2 % at 250 ”g/mL, respectively. The obtained results revealed also that the green synthesized AgNPs were capable to catalyze MB dye. Therefore, the obtained results provide a promising route of the green synthesis of AgNPs using L. royleana leaf extract with considerable biopharmaceuticals and catalytic applications
Antioxidants: Positive or Negative Actors?
The term "antioxidant" is one of the most confusing definitions in biological/medical sciences. In chemistry, "antioxidant" is simply conceived "a compound that removes reactive species, mainly those oxygen-derived", while in a cell context, the conceptual definition of an antioxidant is poorly understood. Indeed, non-clinically recommended antioxidants are often consumed in large amounts by the global population, based on the belief that cancer, inflammation and degenerative diseases are triggered by high oxygen levels (or reactive oxygen species) and that through blocking reactive species production, organic unbalances/disorders can be prevented and/or even treated. The popularity of these chemicals arises in part from the widespread public mistrust of allopathic medicine. In fact, reactive oxygen species play a dual role in dealing with different disorders, since they may contribute to disease onset and/or progression but may also play a key role in disease prevention. Further, the ability of the most commonly used supplements, such as vitamins C, E, selenium, and herbal supplements to decrease pathologic reactive oxygen species is not clearly established. Hence, the present review aims to provide a nuanced understanding of where current knowledge is and where it should go.Antoni Sureda acknowledges the support of Institute of Health Carlos III (Project CIBEROBNCB12/03/30038). NatĂĄlia Martins thank to Portuguese Foundation for Science and Technology (FCTâPortugal) for the Strategic project ref. UID/BIM/04293/2013 and âNORTE2020-Programa Operacional Regional do Norteâ (NORTE-01-0145-FEDER-000012)
Assessment of body mass index and hand anthropometric measurements as independent risk factors for carpal tunnel syndrome
The goal of this study was to clarify the role of body mass index (BMI) (weight
divided by square of height; kg/m2) and hand anthropometric measurements
as independent risk determinants in the development of carpal tunnel syndrome
(CTS) and their relationship to the severity of CTS. A total of 131 patients
with clinical symptoms of CTS and 131 normal subjects were enrolled, of
whom 121 were female both in the CTS cases and the controls. All cases were
electrodiagnostically confirmed and assigned to three severity groups. BMI,
wrist ratio, shape index, digit index and hand length/height ratio were measured
in all participants. Mean values for each item were compared between
cases and controls and severity subgroups. A logistic regression analysis was
performed to determine independent CTS risk factors. The mean values of BMI,
wrist ratio and shape index were significantly higher in all CTS patients and
females compared to controls, whereas in males only BMI and wrist ratio were
higher. The patients in the mild severity subgroup had a significantly lower age
and wrist ratio. BMI, wrist ratio and shape index were found to be independent
risk factors of CTS development in all patients and females. Our study showed
BMI, wrist ratio and shape index as independent risk factors for CTS. These
findings are of potential anatomical and clinical importance and outline the
risk factors of anatomical malfunction of the wrist in CTS.
(Folia Morphol 2008;
67: 36-42
Spatial Structures in a Generalized Ginzburg-Landau Free Energy
Searching for characteristic signatures of a higher order phase transition
(specifically of order three or four), we have calculated the spatial profiles
and the energies of a spatially varying order parameter in one dimension. In
the case of a order phase transition to a superconducting ground
state, the free energy density depends on temperature as , where is the reduced temperature. The energy of a domain wall between
two degenerate ground states is . We have also
investigated the effects of a supercurrent in a narrow wire. These effects are
limited by a critical current which has a temperature dependence . The phase slip center profiles and their energies are also
calculated. Given the suggestion that the superconducting transtion in \bkbox,
for , may be of order four, these predictions have relevance for
future experiments.Comment: 7 pages, 5 figure
Comment on "Quantum Phase Slips and Transport in Ultrathin Superconducting Wires"
In a recent Letter (Phys. Rev. Lett.78, 1552 (1997) ), Zaikin, Golubev, van
Otterlo, and Zimanyi criticized the phenomenological time-dependent
Ginzburg-Laudau model which I used to study the quantum phase-slippage rate for
superconducting wires. They claimed that they developed a "microscopic" model,
made qualitative improvement on my overestimate of the tunnelling barrier due
to electromagnetic field. In this comment, I want to point out that, i), ZGVZ's
result on EM barrier is expected in my paper; ii), their work is also
phenomenological; iii), their renormalization scheme is fundamentally flawed;
iv), they underestimated the barrier for ultrathin wires; v), their comparison
with experiments is incorrect.Comment: Substantial changes made. Zaikin et al's main result was expected
from my work. They underestimated tunneling barrier for ultrathin wires by
one order of magnitude in the exponen
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