The Effect of Carrier Distribution on Performance of ENZ-Based Electro-Absorption Modulator

Recently, epsilon-near-zero (ENZ) has been emerging as an important field of research which is the study of light-matter interactions in the presence of materials with zero permittivity. Since in many scientific works the uniform model of carrier distribution of Indium tin oxide (ITO) has been utilized, we want to investigate ENZ effect in ITO material and the effect of accurate carrier distribution on the performance of a modulator. For this reason, an electro-absorption (EA) modulators with a new configuration based on silicon slot modulator with indium thin oxide material is proposed. To study the effect of ENZ effect in ITO, the semiconductor model (realistic model) is utilized to model the carrier distribution in the ITO material. In this model, there is not any assumption. As a result, by applying the gate voltage, the insertion loss is increased 1.61 dB/μm in comparison with unbiased conditions. Also, the uniform model is used. Compared with the realistic model, the extinction ratio and figure-of-merit significantly enhance based on the uniform model, but the trends of results like insertion loss are so far from the realistic model. It can be found that the realistic model is reliable and the results are closer to reality.

     

Collagen organization in canine myxomatous mitral valve disease: an x-ray diffraction study

Collagen fibrils, a major component of mitral valve leaflets, play an important role in defining shape and providing mechanical strength and flexibility. Histopathological studies show that collagen fibrils undergo dramatic changes in the course of myxomatous mitral valve disease in both dogs and humans. However, little is known about the detailed organization of collagen in this disease. This study was designed to analyze and compare collagen fibril organization in healthy and lesional areas of myxomatous mitral valves of dogs, using synchrotron small-angle x-ray diffraction. The orientation, density, and alignment of collagen fibrils were mapped across six different valves. The findings reveal a preferred collagen alignment in the main body of the leaflets between two commissures. Qualitative and quantitative analysis of the data showed significant differences between affected and lesion-free areas in terms of collagen content, fibril alignment, and total tissue volume. Regression analysis of the amount of collagen compared to the total tissue content at each point revealed a significant relationship between these two parameters in lesion-free but not in affected areas. This is the first time this technique has been used to map collagen fibrils in cardiac tissue; the findings have important applications to human cardiology.     

First Report of Curtobacterium flaccumfaciens pv. flaccumfaciens Causing Cowpea Bacterial Wilt in Iran

During surveys in cowpea fields of Marand County, East Azerbaijan province, Iran, in the summer of 2013, a suspected bacterial disease was observed on cowpea leaves as tan spots and interveinal necrotic lesions surrounded by chlorotic margins. The disease was of high incidence where some fields had been fully destroyed and severity of the disease in some fields had reached up to 70%. Gram‐positive, yellow‐pigmented, coryneform bacteria were isolated from infected leaves. Pathogenicity of isolates was confirmed on 20‐day‐old cowpea (cv. Khoy) plants, and they were identified as Curtobacterium flaccumfaciens pv. flaccumfaciens based on biochemical test results confirmed using specific PCR primers. This is the first report of C. flaccumfaciens pv. flaccumfaciens, the causal agent of cowpea bacterial wilt in Iran.     

Phytochemical and morphological characterization of Satureja khuzistanica Jamzad populations from Iran

Satureja khuzistanica is an endemic herb growing wild in Iran with interesting pharmacological and biological properties. Here, as an initial step of the domestication process, the variability of phytochemical and morphological traits among 69 individuals of eight natural populations of the plant was studied. The investigated characteristics were the essential oil content and composition, the rosmarinic acid (RA) content, and the leaf and flower morphologies. The Abdanan and Kaver populations showed the highest oil contents. The characterization by GC-FID and GC/MS analyses of the oils revealed that all 69 sampled individuals had carvacrol as the main component with very high contents (89.59-95.41%). The content of RA of the MeOH extracts of S. khuzistanica showed a high level of variability (coefficient of variation (CV) 50.0%) ranging from 0.59% (w/w) in the Paalam population to 1.81% (w/w) in the Abdanan population. The peduncle length and the leaf surface area (CVs of 47.39 and 47.21%, resp.) were the most variable morphological characteristics among the examined populations. The high level of phytochemical and morphological variability among the studied populations suggests a breeding approach during the domestication, to gain new, promising, and homogenous cultivars, attractive for the industry and agriculture.     

Alteration of renal functional, oxidative stress and inflammatory indices following hepatic ischemia-reperfusion

Liver ischemia/reperfusion (IR) injury is a complex phenomenon that may cause local as well as remote organ injuries. Reactive oxygen species (ROS) along with many pro- and anti- inflammatory cytokines are implicated in the development of organ injury. The renal functional, histological, oxidative stress and inflammatory indices were studied during a short and a longer period of liver IR. Rats were subjected to either sham operation or 90 min partial liver ischemia followed by 4 or 24 h of reperfusion. Serum ALT, AST, ALK and LDH levels, BUN and creatinine, renal MDA level, SOD and catalase activities were evaluated as well as serum IL-6 and IL-10 concentrations along with renal histological evaluation. Ninety minutes liver ischemia /4 h reperfusion caused an increase in BUN and renal MDA levels and a decrease in SOD and catalase activities. It also caused an increase in serum IL-6 and IL-10 levels. 24 h liver reperfusion resulted in a reduction in BUN levels and lower oxidative damages demonstrated by a decrease in renal MDA levels and an increase in renal SOD and catalase activities comparing to 4 h reperfusion group. Evaluations indicated improvement in histology such as less cytoplasmic vacuolation and lower tubular debris. Serum inflammatory indices (IL-6 and IL-10 levels) were also reduced. This study showed that liver IR damage causes renal injury including functional, inflammatory and oxidative status changes. The remote kidney damage was then improved by continuing reperfusion from 4 to 24 h.     

Docosahexaenoic acid sensitizes Ramos cells to Gamma-irradiation-induced apoptosis through involvement of PPAR-γ activation and NF-κB suppression

The aim of the present study was to characterize the effects of chronic nitric oxide synthase (NOS) inhibition on the alterations of regulatory myocardial proteins of intracellular signaling pathways (mitogen-activated protein kinase (MAPK) and Akt kinase cascades) and matrix metalloproteinases (MMP). Chronic NO deficiency (NOD) was induced by N^G-nitro-L-arginine methyl ester (L-NAME, 40mg/kg/day, 4 weeks). Protein levels and activation of protein kinases were determined using specific antibodies, activities of MMP were analyzed by zymography in gels containing gelatin as a substrate. The development of NOD was associated with decreased activation of endothelial NOS (eNOS) and down-regulation of protein level of inducible NOS (iNOS). Investigation of kinase pathways revealed that the activation of extracellular signal-regulated kinases (ERK) and the levels of upstream activators of ERK (aFGF, H-Ras) were decreased after L-NAME treatment. Western blot analysis revealed that chronic application of L-NAME also decreased the activation of Akt kinase as compared with control hearts. Study of MMPs showed that in L-NAME-treated rat hearts activities of tissue MMP-2 were decreased. It is concluded that development of NOD resulted in inhibition of ERK and Akt kinase pathways and these changes suggest the involvement of these cascades in responses of myocardium to NOD. The results also point to the possible relationship between ERK and Akt kinase pathways and activation of eNOS and/or MMP-2. Anna Špániková and Petra Šimončíková have contributed equally to the study.     

Comparative analysis of essential oil compositions in seven populations of Bakhtiarian savory in natural and field conditions

Bakhtiarian savory (Satureja bachtiarica Bunge) is an endemic herb growing wild in Iran with interesting pharmacological and biological properties. In this research, the variability of essential oil content and phytochemical compositions among seven populations of this species was studied in both natural and field conditions. There was a wide interpopulation variability in phytochemical variation of studied populations under both natural and field conditions, indicating the existence of different chemotypes. Six chemical compositions showed high value in studied plants so that carvacrol and thymol were known as major compounds and confirmed by principal component analysis. Ilam population had the highest thymol in both field (77.10 %) and natural (42.32 %) conditions and was known as a thymol chemotype. Beside, Yazd and Shahrekord populations, respectively, showed the highest carvacrol percentages in both field (84.83 and 63.81 %) and natural (72.50 and 58.05 %) conditions and were known as carvacrol chemotypes. In other populations, carvacrol and thymol were the main components and showed partly equal percentage and these populations were known as carvacrol/thymol chemotypes. According to Pearson correlation analysis, carvacrol was negatively correlated with p-cymene, γ-terpinene and thymol (r = ?0.61, ?0.70 and ?0.98, respectively), indicating very high reverse correlation between carvacrol and thymol. In conclusion, the high value of the essential oil compositions in studied S. bachtiarica populations could provide useful information for conservation and selection of cross parents in breeding programs to develop improved cultivars.     

Assessment of genetic and chemical variability in Thymus caramanicus

Thymus caramanicus is an endemic species grown in Iran with interesting pharmacological and biological properties. In the present work, essential oil compositions and inter-simple sequences repeat (ISSR) markers were used to estimate the relationships among and within seven populations of T. caramanicus, belonging to three provinces in Iran. The studied individuals were distinguished on the basis of ISSR markers and constituents of essential oil. A total of 127 band positions were produced by 12 ISSR primers, of which 105 were found polymorphic with 82.68 % polymorphism. Genetic similarity values among individuals ranged between 0.15 and 0.82 which was indicative of a high level of genetic variation. On the basis of their genetic similarities, ISSR analysis allowed to group the samples into two main clusters. One of these included populations originated from Kerman and Isfahan provinces, and the other cluster consists of populations from Semnan province. Chemical compounds of essential oils were found variable in the various individuals and all samples were principally composed of phenolic constituents (carvacrol and/or thymol). As a consequence, the plants were classified into two major chemotypes including carvacrol and thymol/carvacrol. A relationship between genetic and chemical variability and geographic distribution has been observed in studied populations of T. caramanicus.     

Genetic and Chemical Diversity in Perovskia abrotanoides Kar. (Lamiaceae) Populations Based on ISSRs Markers and Essential Oils Profile

Genetic and the essential oil composition variability among twelve Perovskia abrotanoides populations (PAbPs) growing wild in Iran were assessed by ISSR markers, GC‐FID and GC/MS, respectively. Nine selected ISSR primers produced 119 discernible bands, of them 96 (80.7%) being polymorphic. Genetic similarity values among populations ranged between 0.07 and 0.79 which indicated a high level of genetic variation. Polymorphic information content, resolving power and marker index generated by ISSR primers were, 0.31, 6.14, and 3.32, respectively. UPGMA grouped PAbPs into four main clusters. Altogether, 38 chemical compounds were identified in the oils, and a relatively high variation in their contents was found. Camphor (11.9 – 27.5%), 1,8‐cineole (11.3 – 21.3%), α‐bisabolol (0.0 – 13.1%), α‐pinene (5.9 – 10.8%), and δ‐3‐carene (0.1 – 10.5%) were the major compounds. Oxygenated monoterpenes (32.1 – 35.8%) and monoterpene hydrocarbons (25.7 – 30.4%) were the main groups of compounds in the oils studied. Cluster analysis and principal‐component analysis were used to characterize the samples according to oil components. Four main chemotypes were found to be Chemotype I (camphor/1,8‐cineol), Chemotype II (1,8‐cineole/camphor), Chemotype III (camphor/1,8‐cineol/α‐bisabolol), and Chemotype IV (camphor/δ‐3‐carene/α‐bisabolol). The information, provided here on P. abrotanoides populations, will be useful to introduce this plant into agricultural systems.