Nano silver entrapped in phospholipids membrane: synthesis, characteristics and antibacterial kinetics

The antimicrobial property of stabilized silver nanoparticles (AgNPs) with phospholipid membrane was investigated on both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacterial strains. The influence of phospholipid concentrations on antibacterial kinetics actions of AgNPs was studied with two different methodologies in order to understand the bactericidal and bacteriostatic effects. The bacterial inactivation of synthesized AgNPs fitted well to the Chick-Watson model with a high regression coefficient, R(2) > 0.91. The antibacterial properties of AgNPs depend on the particle size, stabilizer and lecithin concentrations. Only the stabilized AgNPs that have the K(lec/Ag) values of 1 and 2 presented the inhabitation zone, while unstabilized AgNPs agglomerated quickly, settled on the wells and did not diffuse in agar. In addition, the specific coefficient of lethality depends on the lecithin concentration. An increase in lecithin concentration caused multilayer creation on the AgNPs' surface and reduced the release of AgNPs which led to low bacterial killing rate.     

Real‐Time Investigation of Intercalation and Structure Evolution in Printed Polymer:Fullerene Bulk Heterojunction Thin Films

The complex intermixing morphology is critical for the performance of the nanostructured polymer:fullerene bulk heterojunction (BHJ) solar cells. Here, time resolved in situ grazing incidence X‐ray diffraction and grazing incidence small angle X‐ray scattering are used to track the structure formation of BHJ thin films formed from the donor polymer poly(2,5‐bis(3‐hexadecylthiophen‐2‐yl)thieno[3,2‐b]thiophene) with different fullerene derivative acceptors. The formation of stable bimolecular crystals through the intercalation of fullerene molecules between the side chains of polymer crystallites is investigated. Such systems exhibit more efficient exciton dissociation but lower photo‐conductance and faster decay of charges. On the basis of the experimental observations, intercalation obviously takes place before or with the formation of the crystalline polymer domains. It results in more stable structures whose volume remains constant upon further drying. Three distinct periods of drying are observed and the formation of unidimensional fullerene channels along the π‐stacking direction of polymer crystallites is confirmed.     

Genotyping of –374A/T, –429A/G,And 63 bp Ins/Del Polymorphisms of Rage By Rapid One-Step Hexaprimer Amplification Refractory Mutation System Polymerase Chain Reaction in Breast Cancer Patients

Several studies have focused on the RAGE genetic background and have demonstrated that its polymorphisms affect the receptor's activity, expression, and downstream signaling. However, there is only little information regarding RAGE polymorphism in breast cancer. In the present study, the authors studied RAGE polymorphisms in 71 patients with breast cancer and 93 healthy women. RAGE –374T/A, –429T/C, and 63 bp Ins/del polymorphisms were analyzed using a hexaprimer amplification refractory mutation system PCR (H-ARMS-PCR). The results showed that RAGE polymorphisms are not associated with breast cancer in the current study population. Larger studies are required to confirm these data in other populations.     

Bimetallic Core-Shell with Graphene Coating Nanoparticles: Enhanced Optical Properties and Slow Light Propagation

Plasmonics - In this paper, we study the optical properties and surface plasmon resonance of a bimetallic core-shell spherical nanoparticle exhibiting monolayer graphene coatings. The extinction...     

Variation of DAT1 VNTR alleles and genotypes among old ethnic groups in Mesopotamia to the Oxus region

Variation of a VNTR in the DAT1 gene in seven ethnic groups of the Middle East was used to infer the history and affinities of these groups. The populations consisted of Assyrian, Jewish, Zoroastrian, Armenian, Turkmen, and Arab peoples of Iran, Iraq, and Kuwait. Three hundred forty subjects from these seven ethnic groups were screened for DAT1. DAT1 VNTR genotyping showed 3, 6, 7, 8, 9, 10, 11, and 12 alleles in the samples. Analysis of these data revealed differentiation and relationship among the populations. In this region, which covers an area of 2-2.5 million km2, the influence of geography and especially of linguistic characteristics has had potentially major effects on differentiation. Religion also has played a major role in imposing restrictions on some ethnic groups, who as a consequence have maintained their community. Overall, these ethnic groups showed greater heterogeneity compared to other populations.     

Novel O-[11C]methylated derivatives of candesartan as angiotensin II AT1 receptor imaging ligands: Radiosynthesis and ex vivo evaluation in rats

[¹¹C]Methyl-candesartan and its desethyl derivative ([¹¹C]TH4) were developed as potential radiotracers for imaging angiotensin II (Ang II) type 1 (AT₁) receptors. These compounds were synthesized via methylation of tetrazole-protected candesartan using [¹¹C]methyl iodide followed by deprotection through HCl hydrolysis at 65 °C to produce [¹¹C]methyl-candesartan, and 90 °C for [¹¹C]TH4. Ex vivo biodistribution and competition studies were carried out for both [¹¹C]methyl-candesartan and [¹¹C]TH4 to assess tissue retention time course and binding selectivity. Besides the liver, [¹¹C]methyl-candesartan and [¹¹C]TH4 displayed highest tissue retention in the AT₁ receptor-rich renal cortex and outer medulla. At tracer doses 15 min post-injection, [¹¹C]methyl-candesartan demonstrated higher specific binding proportion for AT₁ receptors, and selectivity for AT₁ over Ang II AT₂, Mas, β-adrenergic, and α₂-adrenergic receptors in rat kidneys compared to [¹¹C]TH4. This study indicates that [¹¹C]methyl-candesartan has potential for in vivo imaging renal AT₁ receptors selectively using positron emission tomography.     

LED light mediates phenolic accumulation and enhances antioxidant activity in Melissa officinalis L. under drought stress condition

The popularity of lemon balm in conventional medicine is suggested by the existence of two groups of compounds, namely essential oil and phenylpropanoids pathway derivatives. One of the promising approaches to improve tolerance to drought stress induced oxidative damage in seedlings grown in greenhouses and plant growth chambers is replacing the traditional and high-cost light technologies by recently developed light emitting diodes (LED). In this experiment, we analyzed the role of various LED lights including red (R), blue (B), red (70%) + blue (30%) (RB), and white (W) as well as normal greenhouse light (as control) to stimulate defense mechanisms against drought stress in two genotypes of Melissa officinalis L. The present study demonstrates that pre-treatment with LEDs with high-intensity output for 4 weeks alleviated harmful effects of drought stress in the two genotypes. Under drought stress, RB LED pre-treated plantlets of the two genotypes exhibited the highest relative growth index of shoot and root and total phenolic and anthocyanin content compared to those irradiated with other LEDs and greenhouse lights. The highest amount of malondialdehyde level was detected in R LED exposed plants. In response to drought, LED-exposed plants especially RB light-irradiated plants of the two genotypes maintained significantly higher antioxidant and phenylalanine ammonia-lyase (PAL) enzyme activities and higher expression level of the PAL1 and 4CL-1 genes compared to those irradiated with greenhouse light. We concluded that RB LED light provides a better growth condition and resistance to drought stress for the two genotypes of lemon balm by the highest antioxidant activity and the least amount of damage to the cell membranes. Our data suggest that LED light pre-treatments as moderate stress activate antioxidant systems, enhance the scavenging of ROS and induce drought stress tolerance in the two genotypes of lemon balm plants.

     

RAS/MAPK signaling functions in oxidative stress,DNA damage response and cancer progression

Mitogen-activated protein kinase (MAPK) signaling pathways organize a great constitution network that regulates several physiological processes, like cell growth, differentiation, and apoptotic cell death. Due to the crucial importance of this signaling pathway, dysregulation of the MAPK signaling cascades is involved in the pathogenesis of various human cancer types. Oxidative stress and DNA damage are two important factors which in common lead to carcinogenesis through dysregulation of this signaling pathway. Reactive oxygen species (ROS) are a common subproduct of oxidative energy metabolism and are considered to be a significant physiological modulator of several intracellular signaling pathways including the MAPK pathway. Studies demonstrated that the MAP kinases extracellular signal-regulated kinase (ERK) 1/2 and p38 were activated in response to oxidative stress. In addition, DNA damage is a partly common circumstance in cell life and may result in mutation, cancer, and even cell death. Recently, accumulating evidence illustrated that the MEK/ERK pathway is associated with the suitable performance of cellular DNA damage response (DDR), the main pathway of tumor suppression. During DDR, the MEK/ERK pathway is regularly activated, which contributes to the appropriate activation of DDR checkpoints to inhibit cell division. Therefore, the aim of this review is to comprehensively discuss the critical function of MAPK signaling in oxidative stress, DNA damage, and cancer progression.     

A Series of Pyrene‐Substituted Silicon Phthalocyanines as Near‐IR Sensitizers in Organic Ternary Solar Cells

An attractive method to broaden the absorption bandwidth of polymer/fullerene‐based bulk heterojunction (BHJ) solar cells is to blend near infrared (near‐IR) sensitizers into the host system. Axial substitution of silicon phthalocyanines (Pcs) opens a possibility to modify the chemical, thermodynamic, electronic, and optical properties. Different axial substitutions are already designed to modify the thermodynamic properties of Pcs, but the impact of extending the π‐conjugation of the axial ligand on the opto‐electronic properties, as a function of the length of the alkyl spacer, has not been investigated yet. For this purpose, a novel series of pyrene‐substituted silicon phthalocyanines (SiPc‐Pys) with varying lengths of alkyl chain tethers are synthesized. The UV–vis and external quantum efficiency (EQE) results exhibit an efficient near IR sensitization up to 800 nm, clearly establishing the impact of the pyrene substitution. This yields an increase of over 20% in the short circuit current density (J _SC) and over 50% in the power conversion efficiency (PCE) for the dye‐sensitized ternary device. Charge generation, transport properties, and microstructure are studied using different advanced technologies. Remarkably, these results provide guidance for the diverse and judicious selection of dye sensitizers to overcome the absorption limitation and achieve high efficiency ternary solar cells.