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Physical Chemistry

Elena Benito-Peña, Mayra Granda Valdés, Bettina Glahn-Martínez, Maria C Moreno-Bondi
The application of optical biosensors, specifically those that use optical fibers and planar waveguides, has escalated throughout the years in many fields, including environmental analysis, food safety and clinical diagnosis. Fluorescence is, without doubt, the most popular transducer signal used in these devices because of its higher selectivity and sensitivity, but most of all due to its wide versatility. This paper focuses on the working principles and configurations of fluorescence-based fiber optic and planar waveguide biosensors and will review biological recognition elements, sensing schemes, as well as some major and recent applications, published in the last ten years...
November 2, 2016: Analytica Chimica Acta
Alexander N Shikov, Olga N Pozharitskaya, Valery G Makarov
PURPOSE: Aralia elata var. mandshurica (Rupr. & Maxim.) J.Wen syn. A. mandshurica Rupr. & Maxim is evaluated for its medicinal application. The aim of this study is to analyze pharmacological studies on A. elata var. mandshurica published until December 2015. METHODS: The information regarding the chemistry, safety, effectiveness, and pharmacological and clinical effects of A. elata was systematically collected from the scientific literature through library catalogs; online services such as E-library...
November 15, 2016: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
Tiantian Zhang, Ti-Hsuan Ku, Yuanyuan Han, Ramkumar Subramanian, Iftikhar Ahmad Niaz, Hua Luo, Derrick Chang, Jian-Jang Huang, Yu-Hwa Lo
We present a method, Transient Induced Molecular Electronic Spectroscopy (TIMES), to detect protein-ligand interactions without any protein engineering or chemical modification. We developed a physics model for the TIMES signal and mathematically formulated the problem to attain physical insight of protein-ligand interactions without any disturbances by molecular probes, fluorescent labels, or immobilization of molecules. To demonstrate the functionality of this method, we have used the TIMES signals to find the dissociation constants for the affinity of reactions, the shear-stress dependent adsorption time of molecules on surface, and other interesting features of protein-ligand interaction in native conditions...
October 19, 2016: Scientific Reports
Andrea Fiorani, Filbert Totsingan, Antonio Pollicino, Yifeng Peng, Maria Letizia Focarete, Richard A Gross, Mariastella Scandola
Oligo(Glu70 -co-Leu30 ), a peptide synthesized by protease catalysis, is functionalized at the N-terminus with a 4-pentenoyl unit and grafted to polyLSL[6'Ac,6″Ac], a glycopolymer prepared by ring-opening metathesis polymerization of lactonic sophorolipid diacetate. First, polyLSL[6'Ac,6"Ac] fiber mats are fabricated by electrospinning. Oxidation of the fiber mats and subsequent reaction with cysteamine lead to thiol-functionalized fiber mats with no significant morphology changes. Grafting of the alkene-modified oligopeptide to thiol-functionalized polyLSL[6'Ac,6″Ac] fiber mats is achieved via "thiol-ene" click reaction...
October 18, 2016: Macromolecular Bioscience
Keren Turjeman, Yechezkel Barenholz
BACKGROUND: Steroids are the most efficacious anti-inflammatory agents. However, their toxicities and side-effects compromise their clinical application. Various strategies and major efforts were dedicated for formulating viable liposomal glucocorticosteroids (GCs), so far none of these were approved. OBJECTIVES: To evaluate these approaches for formulating GC-delivery systems, especially liposomes, and with focus on the Barenholz Lab experience. METHODS: We developed PEGylated nano-liposomes (NSSL) remotely loaded with water-soluble amphipathic weak acid GC-prodrugs...
October 18, 2016: Journal of Drug Targeting
Sarwar Beg, Mahfoozur Rahman, Atul Jain, Sumant Saini, Patrick Midoux, Chantal Pichon, Farhan Jalees Ahmad, Sohail Akhter
Metal organic frameworks (MOFs), porous hybrid polymer-metal composites at the nanoscale, are recent innovations in the field of chemistry; they are novel polymeric materials with diverse biomedical applications. MOFs are nanoporous materials, consisting of metal ions linked together by organic bridging ligands. The unique physical and chemical characteristics of MOFs have attracted wider attention from the scientific community, exploring their utility in the field of material science, biology, nanotechnology and drug delivery...
October 11, 2016: Drug Discovery Today
Eugene Stephane Mananga, Bingwen Hu
The importance of the average Hamiltonian theory and its antecedent the Magnus expansion are discussed. The investigation of its convergence in different situations is very important. In this paper, we introduced a well-established approach to minimize the zeroth order average Hamiltonian for modified composite pulse sequence in quadrupolar spectroscopy of spin-1. We designed two modified composite pulse sequences constructed by modifying the timing sequence in the original composite pulse sequences17. We tested various configurations of times associated with the free evolution of spin system in the modified composite pulses...
October 14, 2016: Journal of Physical Chemistry. A
Sasanka Dalapati, Cheng Gu, Donglin Jiang
Enormous research efforts are focusing on the design and synthesis of advanced luminescent systems, owing to their diverse capability in scientific studies and technological developments. In particular, fluorescence systems based on aggregation-induced emission (AIE) have emerged to show great potential for sensing, bio-imaging, and optoelectronic applications. Among them, integrating AIE mechanisms to design porous polymers is unique because it enables the combination of porosity and luminescence activity in one molecular skeleton for functional design...
October 14, 2016: Small
(no author information available yet)
No abstract text is available yet for this article.
October 14, 2016: Angewandte Chemie
Sapna Cheryan, Sianna A Ziegler, Amanda K Montoya, Lily Jiang
Women obtain more than half of U.S. undergraduate degrees in biology, chemistry, and mathematics, yet they earn less than 20% of computer science, engineering, and physics undergraduate degrees (National Science Foundation, 2014a). Gender differences in interest in computer science, engineering, and physics appear even before college. Why are women represented in some science, technology, engineering, and mathematics (STEM) fields more than others? We conduct a critical review of the most commonly cited factors explaining gender disparities in STEM participation and investigate whether these factors explain differential gender participation across STEM fields...
October 10, 2016: Psychological Bulletin
Junsheng Li, Barbara Kwiatkowska, Hao Lu, Maren Voglstätter, Erika Ueda, Michael Grunze, Jonathan Sleeman, Pavel A Levkin, Irina Nazarenko
Malignant transformation is associated with enhancement of cell plasticity, which allows cancer cells to survive under different conditions by adapting to their microenvironment during growth and metastatic spread. Much effort has been devoted to understanding the molecular mechanisms of these processes. Although the importance of the extracellular matrix and of surface properties in these mechanisms is evident, the direct impact of distinct physical and chemical surfaces characteristics on cell fate remains unclear...
October 12, 2016: ACS Applied Materials & Interfaces
Bingbing Wang, Daniel A Knopf, Swarup China, Bruce W Arey, Tristan H Harder, Mary K Gilles, Alexander Laskin
Heterogeneous ice nucleation is a physical chemistry process of critical relevance to a range of topics in the fundamental and applied sciences and technologies. Heterogeneous ice nucleation remains insufficiently understood, partially due to the lack of experimental methods capable of obtaining in situ microscopic details of ice formation over nucleating substrates or particles. We present microscopic observations of ice nucleation events on kaolinite particles at the nanoscale and demonstrate the capability of direct tracking and micro-spectroscopic characterization of individual ice nucleating particles (INPs) in an authentic atmospheric sample...
September 21, 2016: Physical Chemistry Chemical Physics: PCCP
Gabriele Cazzoli, Valerio Lattanzi, Till Kirsch, Jürgen Gauss, Belén Tercero, José Cernicharo, Cristina Puzzarini
CONTEXT: Despite the fact that many sulfur-bearing molecules, ranging from simple diatomic species up to astronomical complex molecules, have been detected in the interstellar medium, the sulfur chemistry in space is largely unknown and a depletion in the abundance of S-containing species has been observed in the cold, dense interstellar medium (ISM). The chemical form of the missing sulfur has yet to be identified. AIMS: For these reasons, in view of the fact that there is a large abundance of triatomic species harbouring sulfur, oxygen, and hydrogen, we decided to investigate the HSO radical in the laboratory to try its astronomical detection...
July 2016: Astronomy and Astrophysics
Sara Houlihan, Diane Decarie, Cindy Benes, Richard Cleve, Marianne Vidler, Laura A Magee, Mary H H Ensom, Peter von Dadelszen
OBJECTIVE: To evaluate the physical compatibility and chemical stability of mixtures of magnesium sulphate and lidocaine in order to determine the feasibility of manufacturing a prefilled syringe combining these two drugs for use as an intramuscular (IM) loading dose for eclampsia prevention and/or treatment. This ready-to-use mixture will provide a more tolerable and accessible route of administration appropriate for widespread use. METHODS: Physical compatibility (pH, colour, and formation of precipitate) and chemical stability (maintaining > 90% of initial concentrations) of mixtures of MgSO4, using both commercially available MgSO4 (50%) and MgSO4 reconstituted from salt (61%), with lidocaine hydrochloride (2%) were evaluated every 14 days over six months...
October 2016: Journal of Obstetrics and Gynaecology Canada: JOGC, Journal D'obstétrique et Gynécologie du Canada: JOGC
E F Silva, R F Bazoni, E B Ramos, M S Rocha
We have investigated the interaction of the DNA molecule with the anticancer drug doxorubicin (doxo) by using three different experimental techniques: single molecule stretching, single molecule imaging and dynamic light scattering. Such techniques allowed us to get new insights on the mechanical behavior of the DNA-doxo complexes as well as on the physical chemistry of the interaction. Firstly, the contour length data obtained from single molecule stretching were used to extract the physicochemical parameters of the DNA-doxo interaction under different buffer conditions...
October 7, 2016: Biopolymers
Christoph Schlaich, Luis Cuellar Camacho, Leixiao Yu, Katharina Achazi, Qiang Wei, Rainer Haag
Facile approaches for the fabrication of substrate independent superamphiphobic surfaces that can repel both water and organic liquids have been limited. The design of such super-repellent surfaces is still a major challenge of surface chemistry and physics. Herein, we describe a simple and efficient dip coating approach for the fabrication of highly hierarchical surface coatings with superamphiphobic properties for a broad range of materials based on a mussel inspired dendritic polymer (MI-dPG). The MI-dPG coating process provides a precise roughness control and the construction of highly hierarchical structures was achieved either directly by pH controlled aggregation or in combination with nanoparticles (NP)...
October 7, 2016: ACS Applied Materials & Interfaces
Alberto Garcia, Jose F Rodriguez Matas, Manuela T Raimondi
Recent evidence suggests that mechanical deformation of the cell nucleus regulates the nuclear import of the transcriptional activators of genes involved in primary physiological cell responses such as stem cell differentiation. In addition, this nuclear mechanosensing response is de-regulated in pathological states, such as cancer and neurodegeneration. One hypothesis that could greatly advance the field is that the deformation of the nuclear envelope activates nuclear pore complexes through a direct mechanical link...
October 10, 2016: Integrative Biology: Quantitative Biosciences From Nano to Macro
Jonathan Tennyson, Laura K McKemmish, Tom Rivlin
Techniques for producing cold and ultracold molecules are enabling the study of chemical reactions and scattering at the quantum scattering limit, with only a few partial waves contributing to the incident channel, leading to the observation and even full control of state-to-state collisions in this regime. A new R-matrix formalism is presented for tackling problems involving low- and ultra-low energy collisions. This general formalism is particularly appropriate for slow collisions occurring on potential energy surfaces with deep wells...
October 4, 2016: Faraday Discussions
Aron Walsh, Nitin P Padure, Sang Il Seok
No abstract text is available yet for this article.
October 5, 2016: Physical Chemistry Chemical Physics: PCCP
Christopher D Jones, Jonathan W Steed
Advances in the field of supramolecular chemistry have made it possible, in many situations, to reliably engineer soft materials to address a specific technological problem. Particularly exciting are "smart" gels that undergo reversible physical changes on exposure to remote, non-invasive environmental stimuli. This review explores the development of gels which are transformed by heat, light and ultrasound, as well as other mechanical inputs, applied voltages and magnetic fields. Focusing on small-molecule gelators, but with reference to organic polymers and metal-organic systems, we examine how the structures of gelator assemblies influence the physical and chemical mechanisms leading to thermo-, photo- and mechano-switchable behaviour...
September 20, 2016: Chemical Society Reviews
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