Structure of bottle-brush brushes under good solvent conditions. A molecular dynamics study

We report a simulation study for bottle-brush polymers grafted on a rigid backbone. Using a standard coarse-grained bead-spring model extensive molecular dynamics simulations for such macromolecules under good solvent conditions are performed. We consider a broad range of parameters and present numerical results for the monomer density profile, density of the untethered ends of the grafted flexible backbones and the correlation function describing the range that neighboring grafted bottle-brushes are affected by the presence of the others due to the excluded volume interactions. The end beads of the flexible backbones of the grafted bottle-brushes do not access the region close to the rigid backbone due to the presence of the side chains of the grafted bottle-brush polymers, which stretch further the chains in the radial directions. Although a number of different correlation lengths exist as a result of the complex structure of these macromolecules, their properties can be tuned with high accuracy in good solvents. Moreover, qualitative differences with "typical" bottle-brushes are discussed. Our results provide a first approach to characterizing such complex macromolecules with a standard bead spring model.Comment: To appear in Journal of Physics Condensed Matter (2011

Electrospinning of continuous poly (L-lactide) yarns:Effect of twist on the morphology, thermal properties and mechanical behavior

Electrospinning PLLA solutions from two oppositely charged nozzles gives a triangle of fibers, also called E-triangle, that assemble into yarns at the convergence point. The formed yarn at the E-triangle was taken up by a unit comprising a take up roller and coupled twister plate, which twist rate can be varied. At all twist rates, uniform and smooth fibers without any beads were formed. The apex angle of the deposited fibers at the E-triangle was larger at higher twist rates. By increasing the twist rate from 80 rpm to 320 rpm the orientation angle of fibers in the yarn changes from 18.8° to 41.5°. Increasing the twist rate revealed a higher polymer crystallinity likely due to the polymer orientation by the applied tension to the fibers. The ultimate strength and modulus of electrospun yarns were higher when prepared at higher twist rates. However, at the highest twist rates, the strength and modulus of electrospun yarns leveled off and even decreased slightly. The results revealed that the mechanical properties not only depend on the polymer crystallinity but also on the alignment of the fibers in the yarn and the angle at which they were deposited. These biodegradable materials are promising materials to be used in a wide range of applications where environmentally friendly products are required

PIWI-interacting RNAs: New biomarkers for diagnosis and treatment of breast cancer

Cancer is one of the most important reasons of mortality in the world. However, there are several therapeutic platforms to treat patients who suffering from cancer common treatments such as surgery, chemotherapy and etc. The current therapeutic approaches are related to some limitations. Hence, more understanding about molecular mechanisms that involved in cancer particularly in breast cancer pathogenesis, could contribute to provide better therapeutic platforms. Recently, non-coding RNAs such as microRNAs have attracted researchers' attention in the field of cancer due to their functions in gene expression's regulation and functional interactions with other molecules. Interestingly, great advances in next-generation sequencing lead to considering other roles for another non-coding RNAs subgroup called PIWI-interacting RNAs (piRNAs) in addition to their functions in the germline. Novel studies investigated the role of piRNAs in several cancers including lung cancer, hepatocellular carcinoma, gastric cancer, multiple myeloma and colorectal cancer. Hopefully, based on new findings, piRNAs may be a potential biomarker which can be used as a tool to diagnose or treat breast cancer. Thus, this review aimed to discuss the role of piRNAs in breast cancer progression and metastasis as well as its molecular mechanisms. © 2020 The Author(s)

The Impact of Digital Technologies and Sustainable Practices on Circular Supply Chain Management

Background: This study investigates how firms can enhance the functionality of their circular supply chains (CSCs) by adopting a portfolio of sustainable practices as well as digital technologies to increase performance. It analyzes the benefits that firms can obtain when investing in specific technologies to boost the impact of technologies and sustainable practices on CSCs, and further increase performance. Methods: We test several hypotheses by using structural equation modeling as well as multi-group analysis to verify whether CSCs can be achieved through sustainable practices and technologies and improve the firms' performance. Results: The empirical results partially support the research hypotheses. While the main research hypotheses are fully supported, the analysis of single digital technologies reveals that only a few solutions can contribute to both the management and the improvement of the CSC. Conclusions: Our findings demonstrate that the identification of green suppliers and ad hoc environmental regulations, combined with attention to the origin and provenance of raw materials, can promote a CSC. Moreover, transportation management systems (TMS) and the internet of things (IoT) are efficient technologies for managing transportation and product flow in the CSC. Furthermore, machine learning (ML) is effective in making positive green decisions, and 3D printing can extend product life

Secretion of Food Allergen Proteins in Saliva

RATIONALE: Peanut proteins were found to be secreted in 50% of lactating women’s breast milk. We wanted to develop a testing method to predict the secretion of peanut protein in breast milk. The secretion of food protein in saliva was hypothesized to be a possible predictor of secretion of foods in breast milk following ingestion. METHODS: Non-allergic volunteers, some lactating, ingested 50 grams of either whole peanuts, peanut milk or cow’s milk and various immunoassays were utilized to analyze for the presence of peanut or cow’s milk proteins in saliva and breast milk. Saliva and breast milk samples were subjected to SDS-PAGE, Western blot and ELISA analysis with anti-raw and roasted peanut and anti-alpha-casein antibodies and pooled serum IgE from peanut allergic individuals. RESULTS: Peanut protein levels in breast milk were undetectable using Western blot analysis and inconsistent with ELISA analysis. However, peanut proteins around 20 and 30 kDa that reacted with anti-roasted peanut antibody were detected, 6-18 hours following ingestion, in saliva of different individuals. An 18 KDa band that reacts with anti-alpha casein antibody was also detected in saliva 6-18 hours following ingestion. CONCLUSIONS: Secretion of food allergen proteins or peptides in saliva several hours following ingestion may have important implications for delayed allergic reaction by sensitive patients. Also, due to the fact that these proteins or peptides survive digestive enzymes, become absorbed into the blood stream and are subsequently secreted in biological fluids may indicate that they are most likely the sensitizing or tolerizing agent within an allergic food. Funding: National Peanut Board, USD

A multi-period location-allocation model for nursing home network planning under uncertainty

This paper proposes a multi-period location- allocation problem arising in nursing home network planning. We present a strategic model in which the improvement of service accessibility through the planning horizon is appropriately addressed. Unlike previous research, the proposed model modifies the allocation pattern to prevent unacceptable deterioration of the accessibility criterion. In addition, the problem is formulated as a covering model in which the capacity of facilities as well as the demand elasticity are considered. The uncertainty in demands within each time period is captured by adopting a distributionally robust approach. The model is then applied to a real case study for nursing home planning network in Shiraz city, Iran

Estimation-based synthesis of H_∞-optimal adaptive equalizers over wireless channels

This paper presents a systematic synthesis procedure for H_∞-optimal adaptive FIR equalizers over a time-varying wireless channel. The channel is assumed to be frequency selective with Rayleigh fading. The proposed equalizer structure consists of the series connection of an adaptive FIR filter and a fixed equalizer (designed for the nominal channel). Adaptation of the weight vector of the adaptive FIR filter is achieved using the H_∞-optimal solution of an estimation-based interpretation of the channel equalization problem. Due to its H_∞-optimality, the proposed solution is robust to exogenous disturbances, and enables fast adaptation (i.e., a short training period) without compromising the steady-state performance of the equalization. Preliminary simulation are presented to support the above claims

Observation of light dragging in rubidium vapor cell

We report on the experimental demonstration of light dragging effect due to atomic motion in a rubidium vapor cell. We found that the minimum group velocity is achieved for light red-shifted from the center of the atomic resonance, and that the value of this shift increases with decreasing group velocity, in agreement with the theoretical predictions by Kocharovskaya, Rostovtsev, and Scully [Phys. Rev. Lett. {\bf 86}, 628 (2001)].Comment: 4 pages 4 figures, submitted to PR