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Weiye Song, Lei Zhang, Steve Ness, Ji Yi
In this paper, we present the first numerical study on full metrics of wavelength-dependent optical properties of melanosomes in retinal pigmented epithelial (RPE) cells. T-matrix method was used to simulate the spheroidal shapes of mature melanosomes, and the complex refractive index was calculated by a subtractive Kramers-Kronig relation for melanin. The validity of the method was first confirmed by Mie theory, and corroborated by a comparison between visible light and near infrared (NIR) optical coherence tomography (OCT) on human retinal imaging...
September 1, 2017: Biomedical Optics Express
Takeharu Wada, Kei Iwasaki, Yasushi Minobe, Mitsuhiro Wada, Shigeo Imai, Satoko Ishii
To determine the amounts and chemical forms of chlorine compounds in elemental chlorine-free (ECF) bleached pulp for sanitary products, a chemical-form-based quantitative analysis flow scheme was created. The scheme involves quantitative determination of compounds eluted in elution tests assuming dermal exposure. The results indicated that most of the chlorine compounds in pulp used for sanitary products were insoluble organically bound chlorine and water-soluble chlorides consisting of chloride ions. The total amount of chlorine obtained by analysis of the total chlorine in the pulp products was close to the sum of the amounts of water-soluble chlorides, residual chlorine, chloroacetic acids, and insoluble organically bound chlorine...
October 9, 2017: Regulatory Toxicology and Pharmacology: RTP
J P Lewis, W F Patterson, J K Carlson
Key methodological assumptions regarding the degree of natural variability and influence of sample handling and storage of elasmobranch vertebral chemistry were assessed using laser-ablation inductively coupled plasma mass spectrometry. Vertebral chemistry of juvenile blacktip sharks Carcharhinus limbatus was examined to identify whether differences existed among different regions of the vertebral column, between thoracic vertebrae of individual fish or within individual vertebrae. Additionally, the effects of bleach exposure and storage in ethanol on vertebral chemistry were compared...
October 10, 2017: Journal of Fish Biology
Tzu-Hsien Lin, Chih-Chieh Chen, Sheng-Hsiu Huang, Chung-Wen Kuo, Chane-Yu Lai, Wen-Yinn Lin
This study investigates the effects of five decontamination methods on the filter quality (qf) of three commercially available electret masks-N95, Gauze and Spunlace nonwoven masks. Newly developed evaluation methods, the overall filter quality (qf,o) and the qf ratio were applied to evaluate the effectiveness of decontamination methods for respirators. A scanning mobility particle sizer is utilized to measure the concentration of polydispersed particles with diameter 14.6-594 nm. The penetration of particles and pressure drop (Δp) through the mask are used to determine qf and qf,o...
2017: PloS One
Robert H Ong, Andrew J C King, Jaap A Kaandorp, Benjamin J Mullins, M Julian Caley
A long-standing interest in marine science is in the degree to which environmental conditions of flow and irradiance, combined with optical, thermal and morphological characteristics of individual coral colonies, affects their sensitivity of thermal microenvironments and susceptibility to stress-induced bleaching within and/or among colonies. The physiological processes in Scleractinian corals tend to scale allometrically as a result of physical and geometric constraints on body size and shape. There is a direct relationship between scaling to thermal stress, thus, the relationship between allometric scaling and rates of heating and cooling in coral microenvironments is a subject of great interest...
2017: PloS One
Masahito Tanaka, Takeomi Kikuchi, Hiroyuki Uno, Keisuke Okita, Toshiko Kitanishi-Yumura, Shigehiko Yumura
The role of cell membrane dynamics in cell migration is unclear. To examine whether total cell surface area changes are required for cell migration, Dictyostelium cells were flattened by agar-overlay. Scanning electron microscopy demonstrated that flattened migrating cells have no membrane reservoirs such as projections and membrane folds. Similarly, optical sectioning fluorescence microscopy showed that the cell surface area does not change during migration. Interestingly, staining of the cell membrane with a fluorescent lipid analogue demonstrated that the turnover rate of cell membrane is closely related to the cell migration velocity...
October 11, 2017: Scientific Reports
Paul R Muir, Paul A Marshall, Ameer Abdulla, J David Aguirre
Mass bleaching associated with unusually high sea temperatures represents one of the greatest threats to corals and coral reef ecosystems. Deeper reef areas are hypothesized as potential refugia, but the susceptibility of Scleractinian species over depth has not been quantified. During the most severe bleaching event on record, we found up to 83% of coral cover severely affected on Maldivian reefs at a depth of 3-5 m, but significantly reduced effects at 24-30 m. Analysis of 153 species' responses showed depth, shading and species identity had strong, significant effects on susceptibility...
October 11, 2017: Proceedings. Biological Sciences
Jih-Terng Wang, Shashank Keshavmurthy, Tzu-Ying Chu, Chaolun Allen Chen
To understand the mechanism of photosynthetic inhibition and generation of reactive oxygen species (ROS) in Symbiodinium types under stress, chemicals such as dichlorophenyl dimethylurea (DCMU) are widely used. Moreover, DCMU and recently menthol were used to generate aposymbiotic cnidarian hosts. While the effects of DCMU on Symbiodinium cells have been extensively studied, no studies have shown the mechanism behind menthol-induced coral bleaching. Moreover, no study has compared the effects of DCMU and menthol treatments on photosystem II (PSII) activity and generation of ROS in different Symbiodinium types...
2017: PeerJ
Peter J Edmunds
The negative implications of the thermal sensitivity of reef corals became clear with coral bleaching throughout the Caribbean in the 1980's, and later globally, with the severe El Niño of 1998 and extensive seawater warming in 2005. These events have substantially contributed to declines in coral cover, and therefore the El Niño of 2016 raised concerns over the implications for coral reefs; on the Great Barrier Reef these concerns have been realized. A different outcome developed in Mo'orea, French Polynesia, where in situ seawater temperature from 15 March 2016 to 15 April 2016 was an average of 0...
2017: PloS One
Ricardo Beldade, Agathe Blandin, Rory O'Donnell, Suzanne C Mills
Organisms can behaviorally, physiologically, and morphologically adjust to environmental variation via integrative hormonal mechanisms, ultimately allowing animals to cope with environmental change. The stress response to environmental and social changes commonly promotes survival at the expense of reproduction. However, despite climate change impacts on population declines and diversity loss, few studies have attributed hormonal stress responses, or their regulatory effects, to climate change in the wild. Here, we report hormonal and fitness responses of individual wild fish to a recent large-scale sea warming event that caused widespread bleaching on coral reefs...
October 10, 2017: Nature Communications
Ahsan Hameed, Syed Ammar Hussain, Junhuan Yang, Muhammad Umair Ijaz, Qing Liu, Hafiz Ansar Rasul Suleria, Yuanda Song
Three important strains of Mucorcircinelloides grown in complete and minimal media for specified period (72 h, 120 h and 168 h) under submerged fermentation conditions were investigated for their potential antioxidants/secondary metabolite production. All mycelial extracts demonstrated effective antioxidant activities in terms of β-carotene/linoleic acid bleaching, radical scavenging, reduction of metal ions and chelating abilities against ferrous ions. Different extraction methods and solvent systems affected the recovery yield and antioxidant activities of the extracts significantly (p ≤ 0...
October 7, 2017: Nutrients
Eman H Ismail, Evren Kilinc, Patrick C Hardigan, James K Rothrock, Jeffrey Y Thompson, Cristina Garcia-Godoy
AIM: The aim of this study is to assess the effect of 35% sodium ascorbate on microtensile bond strength of dentin immediately after bleaching with 35% hydrogen peroxide. MATERIALS AND METHODS: A total of 25 sound human 3(rd) molars were collected. Teeth were randomly divided into five groups for different treatments: Group I [bleaching + immediate bonding (i.e., restoration)], group II (bleaching + delayed bonding), group III (bleaching + sodium ascorbate + immediate bonding), group IV (bleaching + sodium ascorbate + delayed bonding), and group V (bonding only)...
October 1, 2017: Journal of Contemporary Dental Practice
Th I Shaheen, Hossam E Emam
Cellulose nanocrystal (CNC) is a unique material obtained from naturally occurring cellulose fibers. Owing to their mechanical, optical, chemical, and rheological properties, CNC gained significant interest. Herein, we investigate the potential of commercially non-recyclable wood waste, in particular, sawdust as a new resource for CNC. Isolation of CNC from sawdust was conducted as per acid hydrolysis which induced by ultrasonication technique. Thus, sawdust after being alkali delignified prior sodium chlorite bleaching, was subjected to sulfuric acid with concentration of 65% (w/w) at 60(°)C for 60min...
October 6, 2017: International Journal of Biological Macromolecules
Hsiao-Fen Wang, Kuang-Hway Yih, Chao-Hsun Yang, Keh-Feng Huang
This study analyzed 26 commercially available essential oils and their major chemical components to determine their antioxidant activity levels by measuring their total phenolic content (TPC), reducing power (RP), β-carotene bleaching (BCB) activity, trolox equivalent antioxidant capacity (TEAC), and 1,1-diphenyl-2-picrylhydrazyl free radical scavenging (DFRS) ability. The clove bud and thyme borneol essential oils had the highest RP, BCB activity levels, and TPC values among the 26 commercial essential oils...
October 2017: Journal of Food and Drug Analysis
Sara H Sohail, Peter D Dahlberg, Marco A Allodi, Sara C Massey, Po-Chieh Ting, Elizabeth C Martin, C Neil Hunter, Gregory S Engel
In photosynthetic organisms, the pigment-protein complexes that comprise the light-harvesting antenna exhibit complex electronic structures and ultrafast dynamics due to the coupling among the chromophores. Here, we present absorptive two-dimensional (2D) electronic spectra from living cultures of the purple bacterium, Rhodobacter sphaeroides, acquired using gradient assisted photon echo spectroscopy. Diagonal slices through the 2D lineshape of the LH1 stimulated emission/ground state bleach feature reveal a resolvable higher energy population within the B875 manifold...
October 7, 2017: Journal of Chemical Physics
Vandan Shah, Timothy Charlton, Jin Ryoun Kim
High xylanase activity and stability toward alkaline pH is strongly desired for pulping and bleaching processes. We previously enhanced thermal stability of Bacillus circulans xylanase (BCX) by inserting into a thermophilic maltodextrin-binding protein from Pyrococcus furiosus (PfMBP) (the resulting complex named as PfMBP-BCX165). In the present study, we aimed to evolve the inserted BCX domain within PfMBP-BCX165 for greater xylanase activity toward alkaline pH while maintaining enhanced thermal stability...
October 6, 2017: Applied Biochemistry and Biotechnology
Orianne Dumas, Aleta S Wiley, Catherine Quinot, Raphaëlle Varraso, Jan-Paul Zock, Paul K Henneberger, Frank E Speizer, Nicole Le Moual, Carlos A Camargo
Disinfectant use has been associated with adverse respiratory effects among healthcare workers. However, the specific harmful agents have not been elucidated. We examined the association between occupational exposure to disinfectants and asthma control in the Nurses' Health Study II, a large cohort of female nurses.Nurses with asthma were invited in 2014 to complete two questionnaires on their current occupation and asthma (response rate 80%). Asthma control was defined by the Asthma Control Test (ACT). Exposure to major disinfectants was evaluated by a job-task-exposure matrix (JTEM)...
October 2017: European Respiratory Journal: Official Journal of the European Society for Clinical Respiratory Physiology
Cristiane de Melo Alencar, Victor Feliz Pedrinha, Jesuína Lamartine Nogueira Araújo, Renata Antunes Esteves, Ana Daniela Silva da Silveira, Cecy Martins Silva
BACKGROUND: Dental whitening has been increasingly sought out to improve dental aesthetics, but may cause chemical and morphological changes in dental enamel surfaces. OBJECTIVE: This study evaluated in vitro the effect of 10% strontium chloride and 5% potassium nitrate with fluoride on bovine enamel, through tristimulus colorimetry, Knoop microhardness (KHN), and roughness after bleaching with 35% hydrogen peroxide (HP). METHODS: The specimens were divided into three groups (n=15): GControl received bleaching treatment with 35% HP; GNitrate received bleaching with 35% HP followed by the application of 5% potassium nitrate with 2% sodium fluoride; and GStrontium received bleaching with 35% HP followed by the application of 10% strontium chloride on the enamel...
2017: Open Dentistry Journal
I Wongpraparatana, O Matangkasombut, P Thanyasrisung, M Panich
OBJECTIVE: To compare the effect of simulated bleaching with a 10% carbamide peroxide (CP) or a 40% hydrogen peroxide (HP) system on surface roughness of resin composite and resin-modified glass ionomer cement (RMGI) and streptococcal biofilm formation on these surfaces. METHODS AND MATERIALS: Specimens of nanofilled resin composite and RMGI (n=108 each) were randomly divided into three groups (n=36 each): no treatment control, 10% CP, and 40% HP. The surface roughness values (Ra) were measured before and after treatments...
October 4, 2017: Operative Dentistry
Nikolay A Zorin, Alexey A Zabelin, Anatoly Ya Shkuropatov, Anatoly A Tsygankov
The effects of cyanide on enzymatic activity and absorption spectra in the visible and mid-IR (2150-1850cm(-1)) regions were characterized for purified HydSL hydrogenase from the purple sulfur bacterium Thiocapsa (T.) roseopersicina BBS. Prolonged incubation (over hours) of T. roseopersicina hydrogenase with exogenous cyanide was shown to result in an irreversible loss of activity of the enzyme in both the oxidized (as isolated) and H2-reduced states. The frequency position of the active site CO and CN(-) ligand stretching bands in the Fourier transform infrared (FTIR) spectrum of the oxidized form of hydrogenase was not influenced by cyanide treatment...
September 20, 2017: Journal of Inorganic Biochemistry
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