Influence of Anisotropy on Optical Bistability in Plasmonic Nanoparticles with Cylindrical Symmetry

In this paper, the effect of radial anisotropy on optical bistability in the cylindrical nanoshells is theoretically investigated within the quasi-static approximation. We consider two cases: when the shell is anisotropic and the core is nonlinear metal and when the core is anisotropic and the shell is a nonlinear metal. The dependence of optical bistability on the size of the nonlinear/anisotropic shell or core, the embedding medium, the anisotropy parameter, and the type of noble metals as candidates for plasmonics is studied and demonstrated. We show that by changing the type of the plasmonic metal, the switching threshold field changes can be used to design nanoparticle-based all-optical sensors. It is also shown that significant optical bistability and all-optical switching behavior can be obtained in the cylindrical nanoshells due to nonlinearity enhancement via the plasmonic structure.     

Evaluating cytotoxic effect of nanoliposomes encapsulated with umbelliprenin on 4T1 cell line

Cytotoxicity of umbelliprenin has been found in various cancer cell lines such as, prostate, breast, CLL, and skin. Encapsulating chemotherapeutic agents with nanoliposomes have been resulted in improved cytotoxicity effects than their free forms. However, whether nanoliposomal form of umbelliprenin could have higher cytotoxic effect than free umbelliprenin is not clarified yet. After synthesizing umbelliprenin, different concentrations (3, 6, 12, 25, 50, 100, 200 μg/ml) applied on the mouse mammary carcinoma cell line (4T1) for 24, 48, and 72 h at 37°C. Afterwards, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was performed to analyze cytotoxicity. MTT assay results showed that IC₅₀ of umbelliprenin in dimethyl sulfoxide (DMSO) (30.92, 30.64, and 62.23 for 24, 48, 72 h incubation, respectively) decreased (5.8, 5.0, 3.5 for 24, 48, 72 h incubation, respectively) when encapsulated with nanoliposomes. Nanoliposomal umbelliprenin cytotoxicity affected cell viability in concentration and time-dependent manner. Our study recommended nanoliposomal umbelliprenin as the most effective chemotherapeutic agent against the mouse mammary carcinoma cell line viability. Future in vivo studies and clinical trials are needed.     

Facile Supermolecular Aptamer Inhibitors of L-Selectin

Multivalent interactions occur frequently in nature, where they mediate high-affinity interactions between cells, proteins, or molecules. Here, we report on a method to generate multivalent aptamers (Multi-Aptamers) that target L-selectin function using rolling circle amplification (RCA). We find that the L-selectin Multi-Aptamers have increased affinity compared to the monovalent aptamer, are specific to L-selectin, and are capable of inhibiting interactions with endogenous ligands. In addition, the Multi-Aptamers efficiently inhibit L-selectin mediated dynamic adhesion in vitro and homing to secondary lymphoid tissues in vivo. Importantly, our method of generating multivalent materials using RCA avoids many of the challenges associated with current multivalent materials in that the Multi-Aptamers are high affinity, easily produced and modified, and biocompatible. We anticipate that the Multi-Aptamers can serve as a platform technology to modulate diverse cellular processes.     

Three new species of the genus Caesarodispus (Acari: Microdispidae) associated with ants (Hymenoptera: Formicidae), with a key to species

Three new species of the genus Caesarodispus (Acari: Heterostigmatina: Microdispidae) phoretic on ants are described from Iran: C. khaustovi Rahiminejad & Hajiqanbar sp. nov. , C. pheidolei Rahiminejad & Hajiqanbar sp. nov. and C. nodijensis Rahiminejad & Hajiqanbar sp. nov. All species were associated with alate ants of the subfamily Myrmicinae (Hymenoptera: Formicidae) from northern Iran. A key to all species of Caesarodispus is provided.     

Anti-Inflammatory Effects of Lactobacillus Rahmnosus and Bifidobacterium Breve on Cigarette Smoke Activated Human Macrophages

Background

Chronic obstructive pulmonary disease (COPD) is a major global health problem with cigarette smoke (CS) as the main risk factor for its development. Airway inflammation in COPD involves the increased expression of inflammatory mediators such as CXCL-8 and IL-1β which are important mediators for neutrophil recruitment. Macrophages are an important source of these mediators in COPD. Lactobacillus rhamnosus (L. rhamnosus) and Befidobacterium breve (B. breve) attenuate the development of ‘allergic asthma’ in animals but their effects in COPD are unknown.

Objective

To determine the anti-inflammatory effects of L. rhamnosus and B. breve on CS and Toll-like receptor (TLR) activation.

Design

We stimulated the human macrophage cell line THP-1 with CS extract in the presence and absence of L. rhamnosus and B. breve and measured the expression and release of inflammatory mediators by RT-qPCR and ELISA respectively. An activity assay and Western blotting were used to examine NF-κB activation.

Results

Both L. rhamnosus and B. breve were efficiently phagocytized by human macrophages. L. rhamnosus and B. breve significantly suppressed the ability of CS to induce the expression of IL-1β, IL-6, IL-10, IL-23, TNFα, CXCL-8 and HMGB1 release (all p<0.05) in human THP-1 macrophages. Similar suppression of TLR4- and TLR9-induced CXCL8 expression was also observed (p<0.05). The effect of L. rhamnosus and B. breve on inflammatory mediator release was associated with the suppression of CS-induced NF-κB activation (p<0.05).

Conclusions

This data indicate that these probiotics may be useful anti-inflammatory agents in CS-associated disease such as COPD.     

Rethinking Colour Constancy

Colour constancy needs to be reconsidered in light of the limits imposed by metamer mismatching. Metamer mismatching refers to the fact that two objects reflecting metameric light under one illumination may reflect non-metameric light under a second; so two objects appearing as having the same colour under one illuminant can appear as having different colours under a second. Yet since Helmholtz, object colour has generally been believed to remain relatively constant. The deviations from colour constancy registered in experiments are usually thought to be small enough that they do not contradict the notion of colour constancy. However, it is important to determine how the deviations from colour constancy relate to the limits metamer mismatching imposes on constancy. Hence, we calculated metamer mismatching’s effect for the 20 Munsell papers and 8 pairs of illuminants employed in the colour constancy study by Logvinenko and Tokunaga and found it to be so extensive that the two notions—metamer mismatching and colour constancy—must be mutually exclusive. In particular, the notion of colour constancy leads to some paradoxical phenomena such as the possibility of 20 objects having the same colour under chromatic light dispersing into a hue circle of colours under neutral light. Thus, colour constancy refers to a phenomenon, which because of metamer mismatching, simply cannot exist. Moreover, it obscures the really important visual phenomenon; namely, the alteration of object colours induced by illumination change. We show that colour is not an independent, intrinsic attribute of an object, but rather an attribute of an object/light pair, and then define a concept of material colour in terms of equivalence classes of such object/light pairs. We suggest that studying the shift in material colour under a change in illuminant will be more fruitful than pursuing colour constancy’s false premise that colour is an intrinsic attribute of an object.     

Generic Raman‐based calibration models enabling real‐time monitoring of cell culture bioreactors

Raman‐based multivariate calibration models have been developed for real‐time in situ monitoring of multiple process parameters within cell culture bioreactors. Developed models are generic, in the sense that they are applicable to various products, media, and cell lines based on Chinese Hamster Ovarian (CHO) host cells, and are scalable to large pilot and manufacturing scales. Several batches using different CHO‐based cell lines and corresponding proprietary media and process conditions have been used to generate calibration datasets, and models have been validated using independent datasets from separate batch runs. All models have been validated to be generic and capable of predicting process parameters with acceptable accuracy. The developed models allow monitoring multiple key bioprocess metabolic variables, and hence can be utilized as an important enabling tool for Quality by Design approaches which are strongly supported by the U.S. Food and Drug Administration. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:1004–1013, 2015     

Imbalanced serum levels of resolvin E1 (RvE1) and leukotriene B4 (LTB4) in patients with allergic rhinitis

Molecular Biology Reports - Timely and successful resolution of acute inflammation plays a crucial role in preventing the development of chronic airway inflammation in allergic rhinitis (AR). This...