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https://www.readbyqxmd.com/read/28821110/unraveling-the-reaction-mechanism-of-silver-ions-reduction-by-chitosan-from-so-far-neglected-spectroscopic-features
#1
Ana Patrícia Carapeto, Ana Maria Ferraria, Ana Maria Botelho do Rego
Metallic silver nanoparticles were synthesized in aqueous solution using chitosan, as both reducing and stabilizing agent, and AgNO3 as silver precursor aiming the production of solid ultra-thin films. A systematic characterization of the resulting system as a function of the initial concentrations was performed. The combination of UV-vis absorption - and its quantitative analysis - with X-ray photoelectron spectra, light scattering measurements and atomic force microscopy allowed obtaining a rational picture of silver reduction mechanism through the identification of the nature of the formed reduced/oxidized species...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821089/preparation-and-evaluation-of-chitosan-alginate-porous-microspheres-bletilla-striata-polysaccharide-composite-hemostatic-sponges
#2
Chao Wang, Wenfeng Luo, Puwang Li, Sidong Li, Ziming Yang, Zhang Hu, Yangyang Liu, Ningjian Ao
We prepared a novel hemostatic material using chitosan (CS), alginate, and Bletilla striata, which showed good biocompatibility and hemostatic properties. Alginate-calcium porous microspheres (Alg) were prepared by emulsification/cross-linking methods, and Bletilla striata polysaccharide (Bsp) was extracted from the tubers by water extraction and alcohol precipitation. To improve the water absorption and accelerate the blood coagulation, Alg and Bsp were mixed with chitosan solution to form CS/Alg and CS/Alg/Bsp composite sponges by lyophilization...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821035/barley-and-yeast-%C3%AE-glucans-as-new-emulsifier-agents-for-the-development-of-aqueous-natural-antifungal-formulations
#3
Marta Salgado, Soraya Rodríguez-Rojo, María José Cocero
Barley and yeast β-glucans were selected, together with lecithin, to encapsulate resveratrol by emulsification-evaporation method to develop new and safer antifungal formulations. Different emulsification techniques were used: high-shear, high pressure and high pressure and temperature emulsification. Morphology, crystallinity, encapsulation efficiency and in vitro antifungal activity against Botrytis cinerea of the different formulations were evaluated. No significant differences between each emulsification procedure in particle size (below 90nm) and in encapsulation efficiency (70-100%) were observed; only barley β-glucan emulsions showed lower efficiency due to the formation of a gel that retained most of the active compound...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821031/surface-deacetylated-chitin-nanofibers-reinforced-with-a-sulfobutyl-ether-%C3%AE-cyclodextrin-gel-loaded-with-prednisolone-as-potential-therapy-for-inflammatory-bowel-disease
#4
Ryo Tabuchi, Makoto Anraku, Daisuke Iohara, Takako Ishiguro, Shinsuke Ifuku, Tomone Nagae, Kaneto Uekama, Shoko Okazaki, Keizo Takeshita, Masaki Otagiri, Fumitoshi Hirayama
Surface-deacetylated chitin nanofibers (SDACNFs) reinforced with a sulfobutyl ether β-cyclodextrin (SBE-β-CD) (NFs-CDs) gel were developed to obtain a controlled release carrier of prednisolone (PD) for the treatment of colitis. PD was released slowly from the gel at both pH 1.2 and 6.8. The in vitro slow release of PD from the NFs-CDs gel was reflected in the in vivo absorption of the drug after oral administration to rats. These results suggest that a simple gel composed of a mixture of SDACNFs and SBE-β-CD has the potential for use in the controlled release of PD...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28820999/absorption-tissue-distribution-metabolism-and-elimination-of-decabrominated-diphenyl-ether-bde-209-in-rats-after-multi-dose-oral-exposure
#5
Xiu-Bo Mi, Lian-Jun Bao, Chen-Chou Wu, Charles S Wong, Eddy Y Zeng
Human and ecological risks of BDE-209 have drawn much attention, particularly with growing e-waste recycling activities in developing countries. To further address the issue of BDE-209 biotransformation, a laboratory-controlled study was conducted. Female Sprague-Dawley rats were dosed orally by gavage at a daily dose of 1 mg kg(-1) body weight for 7 d and a depuration period of 22 d, to characterize absorption, distribution, metabolism, and elimination dynamics of BDE-209 during multi-dose exposures simulating short-term oral exposure of e-waste workers...
August 13, 2017: Chemosphere
https://www.readbyqxmd.com/read/28820994/relative-bioavailability-and-bioaccessibility-of-pcbs-in-soils-based-on-a-mouse-model-and-tenax-improved-physiologically-based-extraction-test
#6
Chao Li, Ruirui Zhang, Yunzi Li, Shujun Zhang, Peng Gao, Xinyi Cui, Lena Q Ma
In this study, bioavailability of polychlorinated biphenyls (PCBs) in soil samples aged for various time intervals (7 days, 1 and 5 months) was assessed by in vivo tests using mice. The in vivo bioavailability of PCBs in soil ranged from 45% (PCB180 in soil aging for 5 month) to 119% (PCB52 in soil aging for 1 month), indicating that not all PCBs was available for absorption after ingestion of soil samples. The bioaccessibility was assessed using both physiologically-based extraction test (PBET) and Tenax improved PBET (TI-PBET)...
August 8, 2017: Chemosphere
https://www.readbyqxmd.com/read/28820977/a-newly-validated-and-characterized-spectrophotometric-method-for-determination-of-a-three-water-pollutants-metal-ions
#7
Marwa E Mohamed, Eman Y Z Frag, Mona A Mohamed
A simple, fast and accurate spectrophotometric method had been developed to determine lead (II), chromium (III) and barium (II) ions in pure forms and in spiked water samples using thoron (THO) as a reagent forming colored complexes. It was found that the formed complexes absorbed maximally at 539, 540 and 538nm for Pb(II)-THO, Cr(III)-THO and Ba(II)-THO complexes, respectively. The optimum experimental conditions for these complexes had been studied carefully. Beer's law was obeyed in the range 1-35, 1-70, and 1-45μgmL(-1) for Pb (II), Cr(III) and Ba(II) ions with THO reagent, respectively...
August 9, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28820596/processing-solvent-dependent-electronic-and-structural-properties-of-cesium-lead-triiodide-thin-films
#8
Alexandra J Ramadan, Luke A Rochford, Sarah Fearn, Henry J Snaith
Cesium lead triiodide (CsPbI3) is an attractive material for photovoltaic applications due to its appropriate band gap, strong optical absorption and high thermal stability. However, the perovskite phase suffers from moisture induced structural instability. Previous studies have utilized a range of solvent systems to establish the role of solvent choice in structural instabilities. Despite this, effects of different solvents on the electronic structure of this material have not been compared. We report substantial chemical and compositional differences in thin films of CsPbI3 prepared from a range of solvent systems...
August 18, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28820595/vibronic-origin-of-the-qy-absorption-tail-of-bacteriochlorophyll-a-verified-by-fluorescence-excitation-spectroscopy-and-quantum-chemical-simulations
#9
Kristjan Leiger, Juha Matti Linnanto, Arvi Freiberg
The long-wavelength tail of the lowest-energy Qy singlet absorption band of bacteriochlorophyll a in triethylamine peaking at 768.6 nm was examined by means of fluorescence excitation spectroscopy at ambient temperature of 22±1°C. The tail, usually considered a Gaussian, is in fact weakening quasi-exponentially, being clearly evident as far as 940 nm, nearly 2400 cm(-1) (~12 kBT) away from the absorption peak. Quantum chemical simulations identified vibronic transitions from the thermally populated normal modes and their overtones in the ground electronic state as the origin of this tail...
August 18, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28820573/magnetically-aligned-co-c-mwcnts-composite-derived-from-mwcnts-interconnected-zeolitic-imidazolate-frameworks-for-lightweight-and-highly-efficient-electromagnetic-wave-absorber
#10
Yichao Yin, Xiaofang Liu, Xiaojun Wei, Ya Li, Xiaoyu Nie, Ronghai Yu, Jianglan Shui
Developing lightweight and highly efficient electromagnetic wave (EMW) absorbing materials is crucial but challenging for anti-electromagnetic irradiation and interference. Herein, we used MWCNTs as templates for growth of Co-based zeolitic imidazolate frameworks (ZIFs), and obtained Co-C/MWCNTs composite by post pyrolysis. The MWCNTs interconnected the ZIF-derived Co-C porous particles, constructing a conductive network for electron hopping and migration. Moreover, the Co-C/MWCNTs composite was aligned in paraffin matrix under an external magnetic field, which led to the stretch of MWCNTs along the magnetic field direction...
August 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28820482/in-situ-synthesis-of-silver-nanoparticles-on-the-polyelectrolyte-coated-sericin-pva-film-for-enhanced-antibacterial-application
#11
Rui Cai, Gang Tao, Huawei He, Pengchao Guo, Meirong Yang, Chaoxiang Ding, Hua Zuo, Lingyan Wang, Ping Zhao, Yejing Wang
To develop silk sericin (SS) as a potential antibacterial biomaterial, a novel composite of polyelectrolyte multilayers (PEMs) coated sericin/poly(vinyl alcohol) (SS/PVA) film modified with silver nanoparticles (AgNPs) has been developed using a layer-by-layer assembly technique and ultraviolet-assisted AgNPs synthesis method. Ag ions were enriched by PEMs via the electrostatic attraction between Ag ions and PEMs, and then reduced to AgNPs in situ with the assistance of ultraviolet irradiation. PEMs facilitated the high-density growth of AgNPs and protected the synthesized AgNPs due to the formation of a 3D matrix, and thus endowed SS/PVA film with highly effective and durable antibacterial activity...
August 18, 2017: Materials
https://www.readbyqxmd.com/read/28820481/studies-on-the-presence-of-mycotoxins-in-biological-samples-an-overview
#12
REVIEW
Laura Escrivá, Guillermina Font, Lara Manyes, Houda Berrada
Mycotoxins are fungal secondary metabolites with bioaccumulation levels leading to their carry-over into animal fluids, organs, and tissues. As a consequence, mycotoxin determination in biological samples from humans and animals has been reported worldwide. Since most mycotoxins show toxic effects at low concentrations and considering the extremely low levels present in biological samples, the application of reliable detection methods is required. This review summarizes the information regarding the studies involving mycotoxin determination in biological samples over the last 10 years...
August 18, 2017: Toxins
https://www.readbyqxmd.com/read/28820474/significance-of-resveratrol-in-clinical-management-of-chronic-diseases
#13
REVIEW
Awais Wahab, Kuo Gao, Caixia Jia, Feilong Zhang, Guihua Tian, Ghulam Murtaza, Jianxin Chen
Resveratrol could be beneficial to health and provides protection against a wide array of pathologies and age-associated problems, as evident from preclinical studies. However, a comparison of animal and human studies reveals that this dietary polyphenol cannot protect against metabolic diseases and their associated complications. The clinical outcomes are affected by many factors such as sample size. This article not only presents a comprehensive review of the current advances concerning the dose, the extent of absorption, interaction and toxicity of resveratrol in human studies, but also describes its therapeutic effects against several chronic diseases such as diabetes mellitus, obesity, cardiovascular diseases, cancer and aging and the related diseases...
August 18, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28820442/tuning-properties-of-iron-oxide-nanoparticles-in-aqueous-synthesis-without-ligands-to-improve-mri-relaxivity-and-sar
#14
Debora Bonvin, Duncan T L Alexander, Angel Millán, Rafael Piñol, Beatriz Sanz, Gerardo F Goya, Abelardo Martínez, Jessica A M Bastiaansen, Matthias Stuber, Kurt J Schenk, Heinrich Hofmann, Marijana Mionić Ebersold
Aqueous synthesis without ligands of iron oxide nanoparticles (IONPs) with exceptional properties still remains an open issue, because of the challenge to control simultaneously numerous properties of the IONPs in these rigorous settings. To solve this, it is necessary to correlate the synthesis process with their properties, but this correlation is until now not well understood. Here, we study and correlate the structure, crystallinity, morphology, as well as magnetic, relaxometric and heating properties of IONPs obtained for different durations of the hydrothermal treatment that correspond to the different growth stages of IONPs upon initial co-precipitation in aqueous environment without ligands...
August 18, 2017: Nanomaterials
https://www.readbyqxmd.com/read/28820428/pharmacokinetic-analysis-of-an-oral-multicomponent-joint-dietary-supplement-phycox-%C3%A2-in-dogs
#15
Stephanie E Martinez, Ryan Lillico, Ted M Lakowski, Steven A Martinez, Neal M Davies
Despite the lack of safety, efficacy and pharmacokinetic (PK) studies, multicomponent dietary supplements (nutraceuticals) have become increasingly popular as primary or adjunct therapies for clinical osteoarthritis in veterinary medicine. Phycox(®) is a line of multicomponent joint support supplements marketed for joint health in dogs and horses. Many of the active constituents are recognized anti-inflammatory and antioxidant agents. Due to a lack of PK studies in the literature for the product, a pilot PK study of select constituents in Phycox(®) was performed in healthy dogs...
August 18, 2017: Pharmaceutics
https://www.readbyqxmd.com/read/28820347/association-between-eye-diagnosis-and-positive-syphilis-test-results-in-a-large-urban-sexually-transmitted-infection-primary-care-clinic-population
#16
Ann-Marie Lobo, Yan Gao, Laura Rusie, Magda Houlberg, Supriya D Mehta
In 2015, the Centers for Disease Control and Prevention (CDC) and the American Academy of Ophthalmology (AAO) released clinical advisories on rising cases of ocular syphilis. We examined the association between eye disease and syphilis infection among primary care and sexually transmitted infection (STI) clinic patients attending an urban lesbian, gay, bisexual, transgender (LGBT) health center. We conducted a retrospective medical record review of all patients who underwent syphilis testing at Howard Brown Health between 1 January 2010 and 31 December 2015...
January 1, 2017: International Journal of STD & AIDS
https://www.readbyqxmd.com/read/28820277/natural-phospholipids-occurrence-biosynthesis-separation-identification-and-beneficial-health-aspects
#17
Abdelmoneim H Ali, Xiaoqiang Zou, Sherif M Abed, Sameh A Korma, Qingzhe Jin, Xingguo Wang
During the last years, phospholipids (PLs) have attracted great attention because of their crucial roles in providing nutritional values, technological and medical applications. There are considerable proofs that PLs have unique nutritional benefits on human health, such as reducing cholesterol absorption, improving liver functions, and decreasing the risk of cardiovascular diseases. PLs are the main structural lipid components of cell and organelle membranes in all living organisms, and therefore, they occur in all organisms and the derived food products...
August 18, 2017: Critical Reviews in Food Science and Nutrition
https://www.readbyqxmd.com/read/28820223/a-dual-modal-silver-bumpy-nanoprobe-for-photoacoustic-imaging-and-sers-multiplexed-identification-of-in-vivo-lymph-nodes
#18
Myeong Geun Cha, Seunghyun Lee, Sungjo Park, Homan Kang, Sung Gun Lee, Cheolhwan Jeong, Yoon-Sik Lee, Chulhong Kim, Dae Hong Jeong
Multimodal imaging can provide complementary biomedical information which has huge potential in pre-clinical and clinical imaging and sensing. In this study, we introduce dual modal NIR silver bumpy nanoprobes for in vivo imaging and multiplexed detection of biomolecules by both photoacoustic imaging (PAI) and surface-enhanced Raman scattering (SERS) techniques. For this study, we used silica-coated silver bumpy nanoshell probes (AgNS@SiO2). AgNS@SiO2 have strong NIR-absorption and scattering properties compared with other nanostructures, and therefore, can be a good candidate for photoacoustic (PA) and SERS multimodal imaging...
August 18, 2017: Nanoscale
https://www.readbyqxmd.com/read/28820218/photophysical-characterization-and-time-resolved-spectroscopy-of-a-anthradithiophene-dimer-exploring-the-role-of-conformation-in-singlet-fission
#19
Jacob C Dean, Ruomeng Zhang, Rawad K Hallani, Ryan D Pensack, Samuel N Sanders, Daniel G Oblinsky, Sean R Parkin, Luis M Campos, John E Anthony, Gregory D Scholes
Quantitative singlet fission has been observed for a variety of acene derivatives such as tetracene and pentacene, and efforts to extend the library of singlet fission compounds is of current interest. Preliminary calculations suggest anthradithiophenes exhibit significant exothermicity between the first optically-allowed singlet state, S1, and 2 × T1 with an energy difference of >5000 cm(-1). Given the fulfillment of this ingredient for singlet fission, here we investigate the singlet fission capability of a difluorinated anthradithiophene dimer (2ADT) covalently linked by a (dimethylsilyl)ethane bridge and derivatized by triisobutylsilylethynyl (TIBS) groups...
August 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28820199/tuning-the-copper-ii-coordination-properties-of-cyclam-by-subtle-chemical-modifications
#20
Nathalie Camus, Nathalie Le Bris, Selbi Nuryyeva, Matthieu Chessé, David Esteban-Gómez, Carlos Platas-Iglesias, Raphaël Tripier, Mourad Elhabiri
The acid-base and copper(ii) coordination properties of three previously described cyclam derivatives are reported. Potentiometry, mass spectrometry, UV-vis absorption spectroscopy, electrochemistry and theoretical calculations were combined to investigate the protonation and binding properties of Bn-cyclam-EtOH (L1), oxo-cyclam-EtOH (L2) and oxo-Bn-cyclam-EtOH (L3). These three cyclams are C-functionalized by a hydroxyethyl pendant arm and display either one N-benzyl group and/or an amide replacing one macrocyclic secondary amine...
August 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
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