Long-Range Surface Plasmon Resonance–Based Sensitivity Study on D-shaped Ag-MgF2-Coated Models with Analyte Variations

In this report, a novel D-shaped long-range surface plasmon resonance (LRSPR) fiber base sensor has been introduced. The demonstration of proposed sensor involves two D-shaped silver-coated models to study the sensitivity responses. The entire study with the constructed models is based on a single-mode fiber. The models are multilayered consisting of metal, dielectric, and analyte as separate layers. Silver (Ag) and magnesium fluoride (MgF2) strips are used as metal and dielectric layers respectively. The constituency of analyte as an interface excellently standardized the models for sensitivity detection. In this report, a large range of analyte refractive indices (RI) which varies from 1.33 to 1.38 is appraised for the proposed models to characterize the sensitivity. The entire context is encompassed by the wavelength region from 450 to 850 nm with an interval of 20 nm. Sensitivities in this report are measured based on the analyte position from the core and metal for both models. For each of the two models, the analyte is placed as the top layer. RIs of the applied metal (Ag) are measured using the Drude-Lorentz formula. The simulated sensitivities for model-1 and model-2 vary from 6.3?×?10³ nm/RIU to 8.7?×?10³ nm/RIU.

     

Application of linear models for estimation of leaf area in soybean [<Emphasis Type="Italic">Glycine max</Emphasis> (L.) Merr]

Leaf area estimation is an important measurement for comparing plant growth in field and pot experiments. In this study, determination of the leaf area (LA, cm²) in soybean [Glycine max (L.) Merr] involves measurements of leaf parameters such as maximum terminal leaflet length (L, cm), width (W, cm), product of length and width (LW), green leaf dry matter (GLDM) and the total number of green leaflets per plant (TNLP) as independent variables. A two-year study was carried out during 2009 (three cultivars) and 2010 (four cultivars) under field conditions to build a model for estimation of LA across soybean cultivars. Regression analysis of LA vs. L and W revealed several functions that could be used to estimate the area of individual leaflet (LE), trifoliate (T) and total leaf area (TLA). Results showed that the LW-based models were better (highest R ² and smallest RMSE) than models based on L or W and models that used GLDM and TNLP as independent variables. The proposed linear models are: LE = 0.754 + 0.655 LW, (R ² = 0.98), T = −4.869 + 1.923 LW, (R ² = 0.97), and TLA = 6.876 + 1.813 ΣLW (summed product of L and W terminal leaflets per plant), (R ² = 0.99). The validation of the models based on LW and developed on cv. DPX showed that the correlation between calculated and measured LA was strong. Therefore, the proposed models can estimate accurately and massively the LA in soybeans without the use of expensive instrumentation.     

Effects of neem leaf extract on production of aflatoxins and activities of fatty acid synthetase,isocitrate dehydrogenase and glutathione S-transferase in Aspergillus parasiticus

The relationship between the activities of 3 cytosolic enzymes with aflatoxin biosynthesis in Aspergillus parasiticus cultured under different conditions has been investigated in order to find out the role of each enzyme in aflatoxin biosynthesis. Basically the activity of isocitrate dehydrogenase (IDH) was higher in non-toxigenic strains as compared to its counterpart toxigenic fungi (p < 0.05). In contrast, the activities of fatty acid synthase (FAS) as well as glutathione S-transferase (GST) were higher (P < 0.05) in toxigenic strains than that of the non-toxigenic fungi. Aflatoxin production was inhibited in fungi grown in presence of various concentrations of neem leaf extract. Aflatoxin was at its lowest level (>90% inhibition) when the concentration of neem extract was adjusted to 50% (v/v). No significant changes in FAS and IDH activities were observed when aflatoxin synthesis was under restraints by neem (Azadirachta indica) leaf extract. During a certain period of time of culture growth, when aflatoxin production reached to its maximum level, the activity of FAS was slightly induced in the toxigenic strains fed with a low concentration (1.56% v/v) of the neem leaf extract. At the time (96 h) when aflatoxin concentration reached to its maximum levels, the activity of GST in the toxigenic fungi was significantly higher (i.e., 7–11 folds) than that of non-toxigenic strains. The difference was highest in mycelial samples collected after 120 h. However unlike FAS and IDH, GST was readily inhibited (67%) in mycelia fed with 1.56% v/v of the neem extract. The inhibition reached to maximum of 80% in samples exposed to 6.25–12.5% of the extract. These results further substantiate previous finding that there is a positive correlation between GST activity and aflatoxin production in fungi.This revised version was published online in October 2005 with corrections to the Cover Date.     

The relationship between sperm DNA fragmentation,free radicals and antioxidant capacity with idiopathic repeated pregnancy loss

More than two consecutive miscarriages in less than 20 weeks of gestation is defined as recurrent spontaneous miscarriage. Various causes such as uterine anatomical anomalies, genetic factors, and infectious and endocrine disorders have been reported for RPL. However, approximately 50% of the causes are unknown, which can be due to male factors. Several studies have been done on semen parameters to determine the unknown causes and risk factors for miscarriages, however, only studying common semen parameters have not been sufficient. In this study, the relationship between sperm DNA fragmentation, the amount of free radicals, and total antioxidant capacity (TAC) in semen have been considered as a risk factor for spontaneous miscarriage. Semen samples were collected from 42 men whose partners had a history of spontaneous miscarriage and 42 fertile men as the control group. Volume, pH, viscosity, concentration, and motility of semen, as well as sperm morphology were measured. Sperm DNA fragmentation was analyzed by the sperm chromatin structure assay (SCSA) and TUNEL methods, the amount of sperm free radicals was measured by the luminescence method and the total amount of semen antioxidant was measured using the TAC kit. The results have shown that sperm motility in the experimental group was significantly less than the control group (P?=?0.001). The percentage of sperm DNA fragmentation and the amount of free radicals in the experimental group were significantly higher than the control group (P?<?0.001). The total amount of antioxidant was lower in the experimental group compared to the control. Spouses of men with lower sperm motility and higher DNA fragmentation had a higher chance of spontaneous miscarriage when compared to the control group. The results of this study support the hypothesis that sperm DNA fragmentation is a major contributor to spontaneous miscarriage.The relationship between SDF, ROS and TAC with RPL.     

Effect of Piriformospora indica and Sebacina vermifera on plant growth and essential oil yield in Thymus vulgaris in vitro and in vivo experiments

Thymus vulgaris of family Lamiaceae is one of the most plants in pharmacy industries. In this study effect of Piriformospora indica and Sebacina vermifera on growth and development plant, yield and composition of the essential oil in a completely randomized design were evaluated in vitro and in pot culture experiments. Plants were studied by means of plant height, shoot fresh and dry weights, number of shoots, root length, root fresh and dry weights and essential oil analyses. The oil was extracted from the dry matter of shoots by hydro distillation, and their composition was determined by GC/MS. In vitro and in vivo cultures showed that plant height and root length increased in pots inoculated with S. vermifera and P. indica. Maximum fresh and dry weight (shoot and root), number of shoots were observed in pots inoculated with P. indica. In thyme inoculated with S. vermifera and P. indica oil yield increased as compared to non-inoculated control plants. GC and GC/MS revealed that the level of thymol was enhanced as the effect of S. vermifera and P. indica.