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pH mapping

Mohammed Albatany, Alex Li, Susan Meakin, Robert Bartha
Intracellular pH (pHi) plays an important role in the maintenance of normal cell function, and is maintained within a narrow range by the activity of transporters located at the plasma membrane. Modulation of tumor pHi may influence proliferation, apoptosis, chemotherapy resistance, and thermosensitivity. Chemical exchange saturation transfer (CEST) is a novel MRI contrast mechanism that is dependent on cellular pH. Amine and amide concentration-independent detection (AACID) is a recently developed CEST contrast method that is intracellular pH (pHi) weighted...
November 16, 2017: Journal of Neuro-oncology
Naveen Kumar, Martin Peter Andersson, Dirk van den Ende, Frieder Mugele, Igor Siretanu
High resolution Atomic Force Microscopy is used to map the surface charge on the basal planes of kaolinite nanoparticles in an ambient solution of variable pH and NaCl or CaCl2 concentration. Using DLVO theory with charge regulation we determine from the measured force-distance curves the surface charge distribution on both the silica-like and the gibbsite-like basal plane of the kaolinite particles. We observe that both basal planes do carry charge that varies with pH and salt concentration. The silica facet was found to be negatively charged at pH 4 and above, whereas the gibbsite facet is positively charged at pH below 7, and negatively charged at pH above 7...
November 15, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Sujeet Verma, Jason D Zurn, Natalia Salinas, Megan M Mathey, Beatrice Denoyes, James F Hancock, Chad E Finn, Nahla V Bassil, Vance M Whitaker
The cultivated strawberry (Fragaria×ananassa) is consumed worldwide for its flavor and nutritional benefits. Genetic analysis of commercially important traits in strawberry are important for the development of breeding methods and tools for this species. Although several quantitative trait loci (QTL) have been previously detected for fruit quality and flowering traits using low-density genetic maps, clarity on the sub-genomic locations of these QTLs was missing. Recent discoveries in allo-octoploid strawberry genomics led to the development of the IStraw90 single-nucleotide polymorphism (SNP) array, enabling high-density genetic maps and finer resolution QTL analysis...
2017: Horticulture Research
Alireza Khataee, Ramin Hassandoost, Shima Rahim Pouran
The present paper reports the sonocatalytic activity of cerium-substituted-magnetite for removal of oxytetracycline (OTC). The catalyst was prepared through a chemical route (co-precipitation, Fe3-xCexO4) and a mechanical procedure (CeO2/Fe3O4). Subsequently, the physico-chemical characteristics of both samples were determined using XRD, BET, SEM, EDX, TEM, Dot-mapping, FT-IR, DRS, and VSM analysis and compared to pristine magnetite and ceria. Afterwards, the effects of various operational conditions were assessed on sonocatalytic performance of Fe2...
March 2018: Ultrasonics Sonochemistry
Meng-Chan Xia, Lesi Cai, Sichun Zhang, Xinrong Zhang
A new ratiometric fluorescent probe based on cell-penetrating peptides (CPPs) was constructed for whole-cell pH mapping and simultaneous measurement of pH changes in the cytoplasm and lysosomes. The arginine-rich CPP, R12K worked as linker, carrier and part of the fluorophore. Benefiting from R12K, the fluorescent probe is completely water soluble, membrane permeable and well biocompatible. It shows high selectivity, sensitivity and reversibility to pH fluctuations. The ratio of fluorescence intensities F519/F582 increased from 0...
February 1, 2018: Talanta
Zhongbo Zhou, Guocheng Huang, Yi Xiong, Minghao Zhou, Shaoqing Zhang, Chuyang Y Tang, Fangang Meng
A clear understanding of membrane ageing process is essential for the optimization of chemical cleaning in membrane-based facilities. In this study, two-dimensional (2D) Fourier transformation infrared (FTIR) correlation spectroscopy (COS) analysis was firstly used to decipher the sequential order of functional group changes of NaOCl-aged polyethersulfone/polyvinylpyrrolidone (PES/PVP) membranes. The synchronous maps showed twelve major autopeaks in total. Based on the asynchronous maps, a similar ageing sequence of membrane groups was clearly identified at three pH (i...
November 14, 2017: Environmental Science & Technology
Anja Wacker, Fabio Carniato, Carlos Platas-Iglesias, David Esteban-Gomez, Hans-Jürgen Wester, Lorenzo Tei, Johannes Notni
Gadolinium(iii) complexes with pH-dependent relaxivities have been proposed as responsive magnetic resonance imaging (MRI) contrast agents (CA) for mapping of pH value in living subjects. The latter is clinically relevant because hypoxia-induced reduction of interstitial pH (acidosis) is a hallmark of tumor progression and resistance against chemotherapy. In order to obtain versatile building blocks for integration of a pH-responsive MRI-CA functionality into larger molecular assemblies, such as bioconjugates, micelles or nanoparticles, we equipped the structural motif GdDO3A-ethylene(arylsulfonic acid) with additional carboxylic acid moieties in the aromatic para-position...
November 10, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Taruna Anand, Bidhan Ch Bera, Nitin Virmani, Rajesh Kumar Vaid, Medhavi Vashisth, Bhupendra Nath Tripathi
A virulent Aeromonas veronii biovar sobria and the corresponding novel, lytic bacteriophage (VTCCBPA5) were isolated from village pond water. The phage was found to belong to family Podoviridae. PCR analysis of major capsid protein gene confirmed its classification to T7-like genus. The protein profiling by SDS-PAGE indicated the major structural protein to be ~ 45 kDa. The phage (VTCCBPA5) is host specific and is stable over a range of pH (6-10) and temperatures (4-45 °C). On the basis of restriction endonuclease analysis combined with prediction mapping, it was observed to vary significantly from previously reported podophages of Aeromonas sp...
November 7, 2017: Virus Genes
Melody Zhifang Ni, Jeremy R Huddy, Oliver H Priest, Sisse Olsen, Lawrence D Phillips, Patrick M M Bossuyt, George B Hanna
OBJECTIVES: The existing British National Patient Safety Agency (NPSA) safety guideline recommends testing the pH of nasogastric (NG) tube aspirates. Feeding is considered safe if a pH of 5.5 or lower has been observed; otherwise chest X-rays are recommended. Our previous research found that at 5.5, the pH test lacks sensitivity towards oesophageal placements, a major risk identified by feeding experts. The aim of this research is to use a decision analytic modelling approach to systematically assess the safety of the pH test under cut-offs 1-9...
November 4, 2017: BMJ Open
Yanyun Zhao, Yong Ding, Xiangyang Hou, Frank Yonghong Li, Wenjun Han, Xiangjun Yun
Soil represents the largest terrestrial organic carbon pool. To address global climate change, it is essential to explore the soil organic carbon storage patterns and their controlling factors. We investigated the soil organic carbon density (SOCD) in 48 grassland sites along the Eurasian steppe eastern transect (ESET) region, which covers the Inner Mongolia grassland subregion and Mongolia grasslands subregion. Specifically, we analyzed the SOCD in the top 30 cm soil layer and its relationships with climatic variables, soil texture, grazing intensity and community biomass productivity...
2017: PloS One
L Chen, L Wu, J Yu, C-T Kuo, T Jian, I-C Wu, Y Rong, D T Chiu
One constraint of semiconducting polymer dots (Pdots), especially those with near-IR emission, is their low effective emitter ratio (∼1.5 mole percent), which limits their pH sensing performance. The other critical issue of existing Pdot-based pH sensors is their poor photostability. To address these issues, we developed a series of Pdots by dendronizing the squaraine-based pH responsive near-IR emitter, which is covalently incorporated into the polyfluorene (PFO) backbone. The fluorescence self-quenching of the NIR squaraine emitter was effectively suppressed at a high emitter concentration of 5 mole percent...
October 1, 2017: Chemical Science
Edson R A Oliveira, Ricardo B de Alencastro, Bruno A C Horta
Diseases caused by flaviviruses, such as dengue and zika, are globally recognized as major threats. During infection, a critical point in their replicative cycle is the maturation step, which occurs throughout the cellular exocytic pathway. This step is a pH-dependent process that involves the modification of the viral envelope by converting prM (pre-membrane) into M (membrane) proteins with the release of a "pr peptide". After this reaction, the pr peptides remain bound to the viral envelope while the virions cross the acidic trans-Golgi network, and are released only at neutral pH after secretion of the virus particles...
October 24, 2017: Journal of Computer-aided Molecular Design
Kristine T Siao, Bruno H Pypendop, Juhana Honkavaara, Jan E Ilkiw
OBJECTIVE: To characterize the hemodynamic effects of dexmedetomidine, with or without MK-467, following intramuscular (IM) administration in cats. STUDY DESIGN: Randomized, crossover, experimental study. ANIMALS: Six healthy adult male castrated purpose-bred cats. METHODS: Cats were anesthetized with isoflurane in oxygen and instrumented. Cats were administered dexmedetomidine (25 μg kg(-1)), with (DM) or without (D) MK-467 (600 μg kg(-1)), IM in the epaxial muscles...
May 4, 2017: Veterinary Anaesthesia and Analgesia
Leila R Lindeman, Edward A Randtke, Rachel A High, Kyle M Jones, Christine M Howison, Mark D Pagel
PURPOSE: Extracellular pH (pHe) is an important biomarker for cancer cell metabolism. Acido-chemical exchange saturation transfer (CEST) MRI uses the contrast agent iopamidol to create spatial maps of pHe. Measurements of amide proton transfer exchange rates (kex ) from endogenous CEST MRI were compared to pHe measurements by exogenous acido-CEST MRI to determine whether endogenous kex could be used as a proxy for pHe measurements. METHODS: Spatial maps of pHe and kex were obtained using exogenous acidoCEST MRI and an endogenous CEST MRI analyzed with the omega plot method, respectively, to evaluate mouse kidney, a flank tumor model, and a spontaneous lung tumor model...
October 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Ahmed Said Elgebaly
BACKGROUND: Respiratory failure is of concern in the postoperative period after cardiac surgeries. Invasive ventilation (intermittent positive pressure ventilation [IPPV]) carries the risks and complications of intubation and mechanical ventilation (MV). AIMS: Noninvasive positive pressure ventilation (NIPPV) is an alternative method and as effective as IPPV in treating insufficiency of respiration with less complications and minimal effects on respiratory and hemodynamic parameters next to open-heart surgery...
October 2017: Annals of Cardiac Anaesthesia
Nisha Saroj Devi, Rajasekar Shanmugam, Jayanta Ghorai, Meera Ramanan, Pazhamalai Anbarasan, Mukesh Doble
The single-target drugs against the arachidonic acid inflammatory pathway are associated with serious side effects, hence, as a first step towards multi-target drugs, we have studied the pharmacophoric features common to the inhibitors of 5-lipoxygenase-activating protein (FLAP), microsomal prostaglandin E-synthase 1 (mPGES-1) and leukotriene A4 hydrolase (LTA4H). FLAP and mPGES-1 shared subfamily-specific positions (SSPs) and four mPGES-1 inhibitors binding to them mapped onto the pharmacophore derived from FLAP inhibitors (Ph-FLAP)...
October 9, 2017: Molecular Informatics
Alessandro Lunghi, Federico Totti, Stefano Sanvito, Roberta Sessoli
We perform a systematic investigation of the spin-phonon coupling leading to spin relaxation in the prototypical mononuclear single molecule magnet [(tpa(Ph))Fe](-). In particular we analyze in detail the nature of the most relevant vibrational modes giving rise to the relaxation. Our fully ab initio calculations, where the phonon modes are evaluated at the level of density functional theory and the spin-phonon coupling by mapping post-Hartree-Fock electronic structures onto an effective spin Hamiltonian, reveal that acoustic phonons are not active in the spin-phonon relaxation process of dilute SMMs crystals...
September 1, 2017: Chemical Science
Seung-Chul Lee, Chang-Lyoul Lee, Jeongyun Heo, Chan-Uk Jeong, Gyeong-Hui Lee, Sehoon Kim, Woojin Yoon, Hoseop Yun, Sung O Park, Sang Kyu Kwak, Sung-Ha Park, O-Pil Kwon
We report on a series of fluorescent molecular rotors by introducing two rotational groups ("rotators"), which exhibit different rotational and electron-donating abilities. While the controlled molecular rotor, PH, includes a single rotator (the widely used phenyl group), the PO molecular rotors consist of two rotators, a phenyl group and an alkoxy group, which exhibits simultaneous strong electron-donating and easy rotational abilities. Compared to the controlled rotor PH, PO molecular rotors exhibited one order of magnitude higher quantum yield (fluorescence intensity) and simultaneously exhibited significantly higher fluorescence contrast...
October 7, 2017: Chemistry: a European Journal
Kriti Srivastava, Giuseppe Ferrauto, Victor G Young, Silvio Aime, Valérie C Pierre
Accurate mapping of small changes in pH is essential to the diagnosis of diseases such as cancer. The difficulty in mapping pH accurately in vivo resides in the need for the probe to have a ratiometric response so as to be able to independently determine the concentration of the probe in the body independently from its response to pH. The complex Fe(II)-DOTAm-F12 behaves as an MRI contrast agent with dual (19)F and CEST modality. The magnitude of its CEST response is dependent both on the concentration of the complex and on the pH, with a significant increase in saturation transfer between pH 6...
October 5, 2017: Inorganic Chemistry
Sophie Mavrogeni, Roser Pons, Ioannis Nikas, George Papadopoulos, Dimitrios A Verganelakis, Genovefa Kolovou, George P Chrousos
Duchenne muscular dystrophy (DMD) is an X-linked muscle disorder characterized by progressive and irreversible loss of muscular function. As muscular disease progresses, the repair mechanisms cannot compensate for cellular damage, leading inevitably to necrosis and progressive replacement by fibrous and fatty tissue. Cardiomyopathy and respiratory failure are the main causes of death in DMD. In addition to the well-described muscle and heart disease, cognitive dysfunction affects around 30% of DMD boys. Myocardial fibrosis, assessed by late gadolinium enhancement (LGE), using cardiovascular magnetic resonance imaging (CMR), is an early marker of heart involvement in both DMD patients and female carriers...
October 5, 2017: European Journal of Clinical Investigation
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