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Experimental techniques

F Riboli, F Uccheddu, G Monaco, N Caselli, F Intonti, M Gurioli, S E Skipetrov
We present experimental evidence for the different mechanisms driving the fluctuations of the local density of states (LDOS) in disordered photonic systems. We establish a clear link between the microscopic structure of the material and the frequency correlation function of LDOS accessed by a near-field hyperspectral imaging technique. We show, in particular, that short- and long-range frequency correlations of LDOS are controlled by different physical processes (multiple or single scattering processes, respectively) that can be-to some extent-manipulated independently...
July 28, 2017: Physical Review Letters
Blanca Lizarbe, Antoine Cherix, Rolf Gruetter
Magnetic Resonance Spectroscopy is a technique that has the capability of measuring metabolites in vivo and, in appropriate conditions, to infer its metabolic rates. The success of MRS depends a lot on its sensitivity, which limits the usage of X-nuclei MRS. However, technological developments and refinements in methods have made in vivo heteronuclear MRS possible in humans and in small animals. This chapter provides detailed descriptions of the main procedures needed to perform successful in vivo heteronuclear MRS experiments, with a particular focus on experimental setup in 13C MRS experiments in rodents...
2018: Methods in Molecular Biology
Laura Pérez-Cervera, José María Caramés, Luis Miguel Fernández-Mollá, Andrea Moreno, Begoña Fernández, Elena Pérez-Montoyo, David Moratal, Santiago Canals, Jesús Pacheco-Torres
Since its discovery in the early 90s, BOLD signal-based functional Magnetic Resonance Imaging (fMRI) has become a fundamental technique for the study of brain activity in basic and clinical research. Functional MRI signals provide an indirect but robust and quantitative readout of brain activity through the tight coupling between cerebral blood flow and neuronal activation, the so-called neurovascular coupling. Combined with experimental techniques only available in animal models, such as intracerebral micro-stimulation, optogenetics or pharmacogenetics, provides a powerful framework to investigate the impact of specific circuit manipulations on overall brain dynamics...
2018: Methods in Molecular Biology
Hongyu Guo, Gheorghe Stan, Yun Liu
Nanoparticles typically have an inherent wide size distribution that may affect the performance and reliability of many nanomaterials. Because the synthesis and purification of nanoparticles with desirable sizes are crucial to the applications of nanoparticles in various fields including medicine, biology, health care, and energy, there is a great need to search for more efficient and generic methods for size-selective nanoparticle purification/separation. Here we propose and conclusively demonstrate the effectiveness of a size-selective particle purification/separation method based on the critical Casimir force...
January 17, 2018: Soft Matter
Asma Aid, Samira Amokrane, Djamel Nibou, Elhadj Mekatel, Mohamed Trari, Vasile Hulea
The marine biomass Ulva compressa L. (ECL) was used as a low-cost biosorbent for the removal of Cr(VI) from contaminated aqueous solutions. The operating variables were optimized: pH ∼ 2, initial concentration of 25 mg/L, solid/liquid ratio of 6 g/L and a temperature of 50 °C, leading to an uptake elimination of 96%. A full factorial experimental design technique enabled us to obtain a mathematical model describing the Cr(VI) biosorption and to study the main effects and interactions among operational parameters...
January 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Laurie J Points, James Ward Taylor, Jonathan Grizou, Kevin Donkers, Leroy Cronin
Protocell models are used to investigate how cells might have first assembled on Earth. Some, like oil-in-water droplets, can be seemingly simple models, while able to exhibit complex and unpredictable behaviors. How such simple oil-in-water systems can come together to yield complex and life-like behaviors remains a key question. Herein, we illustrate how the combination of automated experimentation and image processing, physicochemical analysis, and machine learning allows significant advances to be made in understanding the driving forces behind oil-in-water droplet behaviors...
January 16, 2018: Proceedings of the National Academy of Sciences of the United States of America
Shazia Ahad, Syed Tanveer, Tauseef Ahmad Malik, Irshad Ahmad Nawchoo
In the interests of food safety and public health, plants and their compounds are now re-emerging as an alternative approach to treat parasitic diseases. Here, we studied the anticoccidial effect of different solvent extracts of the fruit peel of Punica granatum-a commercial waste from pomegranate juice industries. The hope underlying these experiments was to find a sustainable natural product for controlling coccidiosis. The plant extracts were prepared using solvents of different polarity. Acute oral toxicity study was first carried out to see the safety of crude extracts...
January 12, 2018: Microbial Pathogenesis
Antonio Carta, Giuseppina Sanna, Irene Briguglio, Silvia Madeddu, Gabriella Vitale, Sandra Piras, Paola Corona, Alessandra Tiziana Peana, Erik Laurini, Maurizio Fermeglia, Sabrina Pricl, Alessandra Serra, Elisa Carta, Roberta Loddo, Gabriele Giliberti
Enteroviruses are among the most common and important human pathogens for which there are no specific antiviral agents approved by the US Food and Drug Administration so far. Particularly, coxsackievirus infections have a worldwide distribution and can cause many important diseases. We here report the synthesis of new 14 quinoxaline derivatives and the evaluation of their cytotoxicity and antiviral activity against representatives of ssRNA, dsRNA and dsDNA viruses. Promisingly, three compounds showed a very potent and selective antiviral activity against coxsackievirus B5, with EC50 in the sub-micromolar range (0...
December 27, 2017: European Journal of Medicinal Chemistry
Esteban M Schenfeld, Sergio R Ribone, Mario A Quevedo
Despite its vastly demonstrated clinical efficacy, zidovudine (AZT) exhibits several suboptimal pharmacokinetic properties. In particular, its short plasmatic half-life (t1/2 ~ 1 h) is related to its low bound fraction to whole plasmatic proteins and in particular to human serum albumin (HSA). The design of prodrugs constitutes a promising strategy to enhance AZT pharmacokinetic properties, including its affinity for HSA. Recently, we reported the synthesis and chemical stability evaluation of three novel prodrugs of AZT obtained by derivatization with dicarboxylic acids (1-3)...
January 12, 2018: European Journal of Pharmaceutical Sciences
Guanjian Zhao, Qin Huang, Feng Wang, Xiang Zhang, Jiangang Hu, Ying Tan, Ning Huang, Zhigang Wang, Zhibiao Wang, Yuan Cheng
Our previous studies have demonstrated that focused ultrasound (FUS) combined with DNA-loaded microbubbles (MBs) can induce noninvasive, reversible, local disruption of the blood brain barrier (BBB) and enable targeted exogenous gene transfer into the central nervous system. However, due to low gene loading or the absence of positive targeting, to date, there has been no therapeutic effect of MBs combined with FUS in tumor treatment. In the current study, we adopted a phospholipid complex that exhibited sufficient gene loading and peptide-mediated targeting to delay glioma growth...
January 12, 2018: Cancer Letters
Bo Zhang, Junyi Gu, Ming Qian, Lili Niu, Dhanjoo Ghista
OBJECTIVE: This paper presents the use of the texture matching method to measure the rabbit carotid artery elasticity value of the experimental group and control group respectively. It compares the experimental rabbits, when they are prompted by pathological histology to be at the period of carotid atherosclerosis fatty streaks and fiber plaques, with the control group. METHODS: We have used ultrasound linear array probe for scanning the rabbit carotid arteries...
January 16, 2018: Biomedical Engineering Online
Niloufar Shakibapour, Farzad Dehghani Sani, Sima Beigoli, Hamid Sadeghian, Jamshidkhan Chamani
DNA is the primary target of many anticancer drugs involved in important intercellular processes, especially in transcriptional regulation, and histone is known to inhibit gene expression. Small molecules can bind to histone-DNA and impair the cell division, growth, inhibition and apoptosis in cancer cells. In this research, the interaction of a histone H1-calf thymus DNA (ct DNA) complex and propyl acridone (PA) was investigated in Tris-HCl buffer, pH=6.8, using multi-spectroscopic, viscosity and molecular modeling techniques...
January 17, 2018: Journal of Biomolecular Structure & Dynamics
David S Goodsell, Ludovic Autin, Arthur J Olson
Mesoscale molecular modeling is providing a new window on the inner workings of living cells. Modeling of genomes, however, remains a technical challenge, due to their large size and complexity. We describe a lattice method for rapid generation of bacterial nucleoid models that integrates experimental data from a variety of biophysical techniques and provides a starting point for simulation and hypothesis generation. The current method builds models of a circular bacterial genome with supercoiled plectonemes, packed within the small space of the bacterial cell...
January 16, 2018: Journal of Physical Chemistry. B
Ahmad Besaratinia, Albert Zheng, Steven E Bates, Stella Tommasi
To comply with guiding principles for the ethical use of animals for experimental research, the field of mutation research has witnessed a shift of interest from large-scale in vivo animal experiments to small-sized in vitro studies. Mutation assays in cultured cells of transgenic rodents constitute, in many ways, viable alternatives to in vivo mutagenicity experiments in the corresponding animals. A variety of transgenic rodent cell culture models and mutation detection systems have been developed for mutagenicity testing of carcinogens...
January 16, 2018: International Journal of Molecular Sciences
Mark Q Benedict, J Derek Charlwood, Laura C Harrington, L Philip Lounibos, William K Reisen, Walter J Tabachnick
Experimental releases of mosquitoes are performed to understand characteristics of populations related to the biology, ability to transmit pathogens, and ultimately their control. In this article, we discuss considerations related to the safety of experimental releases of living mosquitoes, applying principles of good practice in vector biology that protect human health and comfort. We describe specific factors of experimental releases of mosquitoes that we believe are critical to inform institutional biosafety committees and similar review boards to which proposals to conduct mosquito release experiments have been submitted...
January 2018: Vector Borne and Zoonotic Diseases
Patrick McCormack, Fei Han, Zijie Yan
Light-driven self-organization of metal nanoparticles (NPs) can lead to unique optical matter systems, yet simulation of such self-organization (i.e., optical binding) is a complex computational problem that increases non-linearly with system size. Here we show that a combined electrodynamics-molecular dynamics simulation technique can simulate the trajectories and predict stable configurations of silver NPs in optical fields. The simulated dynamic equilibrium of a two-NP system matches the probability density of oscillations for two optically bound NPs obtained experimentally...
January 16, 2018: Journal of Physical Chemistry Letters
Haibin Zhang, Chunlin Guan, Ning Song, Yuanyuan Zhang, Hong Liu, Jingzhong Fang
Herein, we present an effective bottom-up strategy to fabricate unprecedented macroscopic two-dimensional (2D) plasmonic gold superlattices composed of high-index faceted gold nanocrystal building blocks (NBBs) at the air-liquid interface. In this approach, a synergistic electrostatic and layered self-assembly technique was executed using unique icosidodecahedral gold nanocrystals. It showed that centimeter-squared areas of close-packed monolayer films were formed, and the interparticle spacing of neighbouring Au NBBs could be facilely manipulated from hundreds to several nanometers...
January 16, 2018: Physical Chemistry Chemical Physics: PCCP
Inderdip Shere, Ateeque Malani
Silica polymerization has been extensively used to synthesize various fascinating materials for industrial and technological applications. The polymerization protocol is modified by altering several parameters (such as the concentration of the precursor, temperature, pH) heuristically to obtain the desired end product. To properly understand the effect of such parameters, knowledge of molecular events occurring during the process of polymerization is essential. In this work, we developed algorithms to capture molecular events such as translation, rotation, and reactions using the reaction ensemble Monte Carlo (REMC) technique...
January 16, 2018: Physical Chemistry Chemical Physics: PCCP
Maryam Pourhajibagher, Reza Raoofian, Roghayeh Ghorbanzadeh, Abbas Bahador
BACKGROUND: The infected root canal system harbors one of the highest accumulations of polymicrobial infections. Since the eradication of endopathogenic microbiota is a major goal in endodontic infection therapy, photo-activated disinfection (PAD) can be used as an alternative therapeutic method in endodontic treatment. Compared to cultivation-based approaches, molecular techniques are more reliable for identifying microbial agents associated with endodontic infections. The purpose of this study was to evaluate the ability of designed multiplex real-time PCR protocol for the rapid detection and quantification of six common microorganisms involved in endodontic infection before and after the PAD...
January 11, 2018: Photodiagnosis and Photodynamic Therapy
Ahmed Gaafar Ahmed Gaafar, Basim Anwar Shehata Messiha, Ahmed Mohamed Labib Abdelkafy
Signaling pathways are interesting fields of study of pathogenesis and treatment trials. We elucidated the possible protective effects of nicorandil (15mg/kg/day) and theophylline (20mg/kg/day) on experimentally-induced RA, focusing on the role of JAK (Janus Kinase) / STAT (Signal Transducer and Activator of Transcription) / RANKL (Receptor Activator of Nuclear factor-Kappa B Ligand) / cytokine signaling pathway. Four sets of experiments were performed. First, effect of test agents on normal animals was evaluated...
January 11, 2018: European Journal of Pharmacology
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