Read by QxMD icon Read

Charge screening

Abbas Tanhaeian, Mahmoud Reza Jaafari, Farajollah Shahriari Ahmadi, Roghayyeh Vakili-Ghartavol, Mohammad Hadi Sekhavati
Nowadays, cancer remains a major cause of death affecting millions of people. Currently, the antimicrobial peptides (AMPs) as potent anticancer therapeutic agents offer specificity and low levels of side effects in cancer therapy. In the present study, a cationic chimeric peptide (cLFchimera), derived from camel lactoferrin, was expressed as a secretory peptide using P170 expression system in L. lactis. Peptide purification was carried out using Ni-NTA agarose column from culture medium with 21 μ/mL concentration...
December 14, 2018: Probiotics and Antimicrobial Proteins
Michael McCullagh, Kevin Giles, Keith Richardson, Sara Stead, Martin Palmer
Fluoroquinolones (FLQs) are a class of antimicrobial agents which have been administered to livestock for infection prevention/control and growth promotion. In this work blank porcine muscle extract (fortified with FLQs) has been screened for the FLQ protomer species (resulting from different sites of protonation) using the cumulative specificity of Ultra High Performance Liquid Chromatography coupled with Ion Mobility - Mass Spectrometry (UHPLC-IM-MS) and collision induced dissociation (CID). Collision cross sections (CCSs) and product ion spectra have been generated for the protomeric species with ΔCCS values between protomers ranging between 10-15 Å2 ...
December 14, 2018: Rapid Communications in Mass Spectrometry: RCM
Byung Chul Lee, Junhong Na, Jun Hee Choi, Hyunjin Ji, Gyu-Tae Kim, Min-Kyu Joo
Charge carrier transport in multilayer van der Waals (vdW) materials, which comprise multiple conducting layers, is well described using Thomas-Fermi charge screening (λTF ) and interlayer resistance (Rint ). When both effects occur in carrier transport, a channel centroid migrates along the c-axis according to a vertical electrostatic force, causing redistribution of the conduction centroid in a multilayer system, unlike a conventional bulk material. Thus far, numerous unique properties of vdW materials are discovered, but direct evidence for distinctive charge transport behavior in 2D layered materials is not demonstrated...
December 13, 2018: Advanced Materials
Junli Chang, Hongkuan Yuan, Biao Wang, Yuhong Huang, Xiaorui Chen, Hong Chen
Organometal halide perovskites have been outstanding from enormous amount of functional materials thanks to their highly cost-effective processability and prominent light harvesting capacity. Unfortunately, poor long-term stability seriously hinders their further development. The recent experimental observations suggest that Cesium is a promising candidate to enhance the stability of MAPbI$_3$. To explore the inherent mechanism, a first-principles investigation based on density functional theory, including hybrid functional, has been performed to analyze the electronic and optical properties of perovskite series MA$_{0...
December 12, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Di Xu, Hujiang Shen, Wei Wang, Junjie Xie, Tao Zhang, Huihui Yuan, Yuyu Li, Xinyu Chen, Yunlong He, Yumei Zhang
Post-treatment was performed for poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films screen-printed on fluorine-doped tin oxide (FTO) substrates, to improve their charge transfer efficiency. Different H₂SO₄ solutions including concentrated H₂SO₄ and H₂SO₄ diluted with H₂O or dimethyl sulfoxide (DMSO) were adopted during the post-treatment. The adhesion of the as-treated films was evaluated by adhesive tape peeling tests, the surface morphology and vertical charge transfer from the films to the substrates were investigated by current-sensing atomic force microscopy, and the catalytic activities toward I₃- reduction of PEDOT:PSS films were characterized via electrochemical measurements...
December 12, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Flavio S Nogueira, Zohar Nussinov, Jeroen van den Brink
Recently, two fundamental topological properties of a magnetic vortex at the interface of a superconductor (SC) and a strong topological insulator (TI) have been established: The vortex carries both a Majorana zero mode relevant for topological quantum computation and, for a time-reversal invariant TI, a charge of e/4. This fractional charge is caused by the axion term in the electromagnetic Lagrangian of the TI. Here we determine the angular momentum J of the vortices, which in turn determines their mutual statistics...
November 30, 2018: Physical Review Letters
Sunny Gupta, Ji-Hui Yang, Boris I Yakobson
Single photon emission (SPE) by a solid state source requires presence of a distinct two-level quantum system, usually provided by point defects. Here we note that a number of qualities offered by novel, two dimensional materials-their all-surface openness and optical transparence, tighter quantum confinement, and reduced charge screening-are advantageous for achieving an ideal SPE. Based on first principles calculations and point-group symmetry analysis, a strategy is proposed to design paramagnetic defect complex with reduced symmetry, meeting all the requirements for SPE: its electronic states are well isolated from the host material bands, belong to a majority spin eigenstate, and can be controllably excited by polarized light...
December 11, 2018: Nano Letters
Yoshio Okiyama, Chiduru Watanabe, Kaori Fukuzawa, Yuji Mochizuki, Tatsuya Nakano, Shigenori Tanaka
In this study, the electronic properties of bioactive proteins were analyzed using an ab initio fragment molecular orbital (FMO) methodology in solution: coupling with an implicit solvent model based on the Poisson-Boltzmann surface area called as FMO-PBSA. We investigated the solvent effects on practical and heterogeneous targets with uneven exposure to solvents unlike deoxyribonucleic acid analyzed in our recent study. Interfragment interaction energy (IFIE) and its decomposition analyses by FMO-PBSA revealed solvent-screening mechanisms that affect local stability inside ubiquitin protein: The screening suppresses excessiveness in bare charge-charge interactions and enables an intuitive IFIE analysis...
December 11, 2018: Journal of Physical Chemistry. B
Sami Mnif, Marwa Jardak, Imen Grait, Salwa Abid, Dorra Abdelmalek, Najla Kharrat
A cationic cell-penetrating peptide PEP-NJSM was identified in human virus proteomes by a screening of charge clusters in protein sequences generating cell penetrating peptides (CPP). PEP-NJSM was selectively active against Gram positive Staphylococcus epidermidis as antibacterial agent with MIC value of 128 μM compared to the Gram-negative Pseudomonas aeruginosa strain with MIC value exceeded 512 μM. The selected peptide exhibited an important anti-biofilm activity even at sub-MIC levels. PEP-NJSM could prevent biofilm formation and increase the mortality of cells inside mature S...
December 3, 2018: International Journal of Biological Macromolecules
Xin He, David J Singh, Patsorn Boon-On, Ming-Way Lee, Lijun Zhang
Dielectric screening plays an important role in reducing the strength of carrier scattering and trapping by point defects for many semiconductors such as the halide perovskite solar materials. However, it was rarely considered as a screen to find new electronic semiconductors. We performed a material search study using the dielectric properties as a screen to identify potential electronic materials in the class of metal-pnictide ternary sulfosalts, containing Bi or Sb. These salts are basically ionic due to the electronegativity difference between both the S and both the metal and pnictogen elements...
December 5, 2018: Journal of the American Chemical Society
Un Jeong Kim, Jun Suk Kim, Noejung Park, Sanghyub Lee, Ukjae Lee, Yeonsang Park, Jinbong Seok, Sungwoo Hwang, Hyungbin Son, Young Hee Lee
Metal/graphene interface has been one of the most important research topics with regard to charge screening, charge transfer, contact resistance, and solar cells. Chemical bond formation of metal/graphene can be deduced from the defect induced D-band and its second-order mode, 2D band, measured by Raman spectroscopy, as a simple and non-destructive method. However, a phonon mode located at ~ 1350 cm-1 , which is normally known as the defect-induced D-band, is intriguing for graphene deposited with noble metals (Ag, Au, and Cu)...
December 5, 2018: ACS Nano
Mingsong Shi, Dingguo Xu, Jun Zeng
Quantum mechanical approaches for the massive computation on large biological system such as virtual screening in drug design and development have presented a challenge to computational chemists for many years. In this study, we demonstrated that by taking advantage of rapid growth of GPU-based hardware and software (i.e., teraChem), it is feasible to perform virtual screening of a refined chemical library at quantum mechanical level in order to identify the lead compounds with improved accuracy, especially for the drug targets such as metalloproteins in which significant charge transfer and polarization occur amongst the metal ions and their coordinated amino acids...
2018: Frontiers in Chemistry
Yanping Sun, Hui Liu, Tianzhi Yang, Lang Lang, Lin Cheng, Haonan Xing, Li Yang, Pingtian Ding
In order to balance transfection efficiency and cytotoxicity as well as screen the optimal polymers for gene delivery, a series of amphoteric copolymers (poly(CBA-AGM/GABA)s) composed of different ratios between agmatine (AGM) and γ-aminobutyric acid (GABA) monomers were synthesized. The AGM containing positively charged guanidinium groups was used to improve transfection efficiency, while the GABA containing negatively charged carboxyl groups was used to decrease cytotoxicity. It is hypothesized that the amphoteric poly(CBA-AGM/GABA)s synthesized at the optimal ratio of both components would well balance transfection efficiency and cytotoxicity...
November 20, 2018: Colloids and Surfaces. B, Biointerfaces
Shiyu Hu, Jun Gao
Charge injection at a metal/semiconductor interface is of paramount importance for many chemical and physical processes. The dual injection of electrons and holes, for example, is necessary for electroluminescence in organic light-emitting devices. In an electrochemical cell, charge transfer across the electrode interface is responsible for redox reactions and faradic current flow. In this work, we use polymer light-emitting electrochemical cells (PLECs) to visually assess the ability of metals to inject electronic charges into a luminescent polymer...
December 3, 2018: ACS Applied Materials & Interfaces
Kazunori Sasaki, Hitoshi Sagawa, Makoto Suzuki, Hiroyuki Yamamoto, Masaru Tomita, Tomoyoshi Soga, Yoshiaki Ohashi
Metabolome analysis using capillary electrophoresis (CE) coupled with high-resolution mass spectrometry (HRMS) has the potential to improve coverage of metabolite detection due to its high selectivity and sensitivity. Configuration of the interface between CE and HRMS to meet the ground connection is essential to enable independent regulation of the electrical currents in the CE and electrospray field. In the present study, we applied an electrospray ionization adapter equipped with a grounded nebulizer to CE-HRMS and tested the analytical performance for 34 charged compounds...
November 30, 2018: Analytical Chemistry
Yingying Yang, Yuelin Wang, Man Yao, Xudong Wang, Hao Huang
A series of early transition-metal carbides (TMCs) in the NaCl structure have been constructed to compare the catalytic activity in Li-O2 batteries by first-principles calculations. The reasonable interfacial models of LixO2 (x = 4, 2, and 1) molecules adsorbed on early TMCs surfaces were used to simulate oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) processes. Taking overpotentials as a merit parameter of catalytic activity, more relationships between material properties relative to the adsorption/desorption behavior of active molecules and catalytic activity are constructed for early TMCs...
November 30, 2018: Physical Chemistry Chemical Physics: PCCP
Maximilian Pleines, Werner Kunz, Thomas Zemb, Daniel Benczédi, Wolfgang Fieber
HYPOTHESIS: The formation of transient networks of giant micelles leads to a viscosity peak when salt is added to aqueous solutions of charged surfactants. It is the consequence of an increase of the packing parameter due to charge screening of the surfactant headgroups, leading to a continuous transformation of the aggregates from spherical to wormlike micelles, and finally to branched networks. It should therefore be possible to predict the macroscopic viscosity of entangled giant micelles by modelling the packing parameter at nanoscale...
November 19, 2018: Journal of Colloid and Interface Science
Phuong T Hoang, Dominic Hodgkin, John P Thomas, Grant Ritter, Jon Chilingerian
RATIONALE AND OBJECTIVE: To evaluate the relationship between receipt of annual physicals and the receipt of provider recommendation for preventive services, during a period when Medicare did not cover annual physicals (before 2011). METHODS: Electronic medical records of patients aged 65 years and older from a US health care system were extracted for the 2001 to 2007 period. A fixed-effects logistic model was used to assess the relationship between receipt of periodic health examination (PHE) and receipt of provider recommendation for mammogram screening for 6466 female Medicare beneficiaries...
November 29, 2018: Journal of Evaluation in Clinical Practice
Timothy Pham, R Chris Rathbun, Shellie Keast, Nancy Nesser, Kevin Farmer, Grant Skrepnek
RATIONALE, AIMS, AND OBJECTIVES: To assess inpatient clinical and economic outcomes for AIDS/HIV and Hepatitis C (HCV) co-infection in the United States from 2003 to 2014. METHOD: This historical cohort study utilized nationally representative hospital discharge data to investigate inpatient mortality, length of stay (LoS), and inflation-adjusted charges among adults (≥18 years). Outcomes were analysed via multivariable generalized linear models according to demographics, hospital and clinical characteristics, and AIDS/HIV or HCV sequelae...
November 28, 2018: Journal of Evaluation in Clinical Practice
Maryam Nikkhou, Igor Muševič
We demonstrate how the geometric shape of a rod in a nematic liquid crystal can stabilise a large number of oppositely charged topological defects. A rod is of the same shape as a sphere, both having genus g = 0, which means that the sum of all topological charges of defects on a rod has to be -1 according to the Gauss-Bonnet theorem. If the rod is straight, it usually shows only one hyperbolic hedgehog or a Saturn ring defect with negative unit charge. Multiple unit charges can be stabilised either by friction or large length, which screens the pair-interaction of unit charges...
November 28, 2018: Soft Matter
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"