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Laser o2 generation

Arpit Bhargava, Vikram Pareek, Subhasree Roy Choudhury, Jitendra Panwar, Surajit Karmakar
Pseudomonas aeruginosa, a gram-negative rod-shaped bacterium is a notorious pathogen causing chronic infections. Its ability to form antibiotic resistant biofilm has raised the need for the development of alternative treatment approaches. An ideal alternate can be silver nanoparticles known for their strong yet tuneable bactericidal activity. However, their use in the commercial in vivo medicine could not see the light of the day because of the unwanted toxicity of silver in the host cells at higher concentrations...
August 10, 2018: ACS Applied Materials & Interfaces
Michelle L Duquette, Justine Kim, Linda Z Shi, Michael W Berns
The redox state of the cell can be affected by many cellular conditions. In this study we show that detectable reactive oxygen species (ROS) are also generated in response to DNA damage by the chromatin remodeling factor and monoamine oxidase LSD1/KDM1A. This raised the possibility that the localized generation of hydrogen peroxide produced by LSD1 may affect the function of proximally located DNA repair proteins. The two major pathways for repair of DNA double-strand breaks (DSBs) are homologous recombination (HR) and non-homologous end joining (NHEJ)...
2018: PloS One
Lihua Zhou, Yayun Wu, Xiaoqing Meng, Sanpeng Li, Jiali Zhang, Ping Gong, Pengfei Zhang, Tao Jiang, Guanjun Deng, Wenjun Li, Zhihong Sun, Lintao Cai
Phototherapy is a promising treatment method for cancer therapy. However, the various factors have greatly restricted phototherapy development, including the poor accumulation of photosensitizer in tumor, hypoxia in solid tumor tissue and systemic phototoxicity. Herein, a mitochondrial-targeted multifunctional dye-anchored manganese oxide nanoparticle (IR808@MnO NP) is developed for enhancing phototherapy of cancer. In this nanoplatform, IR808 as a small molecule dye acts as a tumor targeting ligand to make IR808@MnO NPs with capacity to actively target tumor cells and relocate finally in the mitochondria...
August 10, 2018: Small
Thomas S Wilhelm, Zihao Wang, Mohadeseh A Baboli, Jian Yan, Stefan F Preble, Parsian K Mohseni
The ternary III-V semiconductor compound, Al x Ga1 -x As, is an important material that serves a central role within a variety of nanoelectronic, optoelectronic, and photovoltaic devices. With all of its uses, the material itself poses a host of fabrication difficulties stemming from conventional top-down processing, including standard wet-chemical etching and reactive-ion etching (RIE). Metal-assisted chemical etching (MacEtch) techniques provide low-cost and benchtop methods that combine many of the advantages of RIE and wet-chemical etching, without being hindered by many of their disadvantages...
August 6, 2018: ACS Applied Materials & Interfaces
Victoria P Barber, Shubhrangshu Pandit, Amy M Green, Nisalak Trongsiriwat, Patrick J Walsh, Stephen J Klippenstein, Marsha I Lester
The reaction of ozone with isoprene, one of the most abundant volatile organic compounds in the atmosphere, produces three distinct carbonyl oxide species (RR'COO) known as Criegee intermediates: formaldehyde oxide (CH2OO), methyl vinyl ketone oxide (MVK-OO), and methacrolein oxide (MACR-OO). The nature of the substituents (R,R' = H, CH3, CH=CH2) and conformations of the Criegee intermediates control their subsequent chemistry in the atmosphere. In particular, unimolecular decay of MVK-OO is predicted to be the major source of hydroxyl radicals (OH) in isoprene ozonolysis...
August 3, 2018: Journal of the American Chemical Society
David Kingsley, Robinson Kuis, Rafael Perez, Isaac Basaldua, Paul Burkins, Aristides Marcano, Anthony Johnson
BACKGROUND: Previous work indicated that an ultrashort pulse (USP) 425 nm laser is capable of inactivating murine norovirus (MNV: Virol. J. 11:20), perhaps via an impulsive stimulated Raman scattering (ISRS) mechanism, and does not substantially damage human plasma proteins (PLOS One 9:11). Here, further investigation of virus inactivation by laser light is performed. METHODS: In this study, we evaluate whether inactivation of MNV is specific to the USP wavelength of 425 nm, or if it occurs at other visible wavelengths, using a tunable mode-locked Ti-Sapphire laser that has been frequency doubled to generate femtosecond pulses at wavelengths of 400, 408, 425, 450, 465, and 510 nm...
July 31, 2018: Virology Journal
Aaron M Chalifoux, Georgia C Boles, Giel Berden, Jos Oomens, P B Armentrout
Arginine (Arg) complexes with Zn2+ and Cd2+ were examined by infrared multiple photon dissociation (IRMPD) action spectroscopy using light from a free electron laser. Electrospray ionization generated complexes of deprotonated Arg with Zn2+, [Zn(Arg-H)]+, and Arg with CdCl+, CdCl+(Arg). Possible low-energy conformers of these species were found using quantum chemical calculations, and their calculated IR spectra were compared to experimentally measured IRMPD spectra. Calculations were performed at the B3LYP/6-311+G(d,p) level for Zn2+ complexes and B3LYP/def2-TZVP with an SDD effective core potential on cadmium for CdCl+ complexes...
July 31, 2018: Physical Chemistry Chemical Physics: PCCP
Xinhong Gan, Ying Teng, Ling Zhao, Wenjie Ren, Wei Chen, Jialong Hao, Peter Christie, Yongming Luo
Iron oxides are reactive inorganic soil components that play an important role in the fate and transport of organic pollutants. Here, hematite was selected to investigate its effect on the biodegradation of benzo[a]pyrene (BaP) by Paracoccus sp. strain HPD-2. Approximately 60% of the total BaP was degraded in the absence of hematite after 7 days but only 30.8 and 20.8% of that was degraded after the addition of 10 and 20 mg  mL-1 hematite, respectively, indicating that the addition of hematite could significantly inhibit the biodegradation of BaP (P < 0...
July 18, 2018: Journal of Hazardous Materials
Vinay Idikuda, Weihua Gao, Khade Grant, Zhuocheng Su, Qinglian Liu, Lei Zhou
Photochemically or metabolically generated singlet oxygen (1 O2 ) reacts broadly with macromolecules in the cell. Because of its short lifetime and working distance, 1 O2 holds potential as an effective and precise nanoscale tool for basic research and clinical practice. Here we investigate the modification of the spHCN channel that results from photochemically and chemically generated 1 O2 The spHCN channel shows strong voltage-dependent inactivation in the absence of cAMP. In the presence of photosensitizers, short laser pulses transform the gating properties of spHCN by abolishing inactivation and increasing the macroscopic current amplitude...
July 24, 2018: Journal of General Physiology
N Shahemi, S Liza, A A Abbas, A M Merican
A revision of a metal-on-ultra high molecular weight (UHMWPE) bearing couple for total hip replacement was performed due to aseptic loosening after 23 years in-vivo. It is a major long-term failure identified from wear generation. This study includes performing failure analysis of retrieved polyethylene acetabular cup from Zimmer Trilogy® Acetabular system. The UHMWPE acetabular cup was retrieved from a 61 years old male patient with ability to walk but limited leg movement when he presented to hospital in early 2016 with complaint left thigh pain...
July 11, 2018: Journal of the Mechanical Behavior of Biomedical Materials
Andreas Looft, Michael Pfitzner, Annegret Preuß, Beate Róder
BACKGROUND: Direct singlet molecular oxygen detection is known to be a valuable tool for understanding photodynamic action. It could become useful for optimizing illumination schedules in photodynamic therapy. The method of time resolved singlet molecular oxygen luminescence detection can give insights into generation of singlet oxygen and its interaction with the environment and therefore possibly allows monitoring the treatments efficacy. Due to high requirements for sensitivity as well as time resolution it has not yet been used in situ...
July 16, 2018: Photodiagnosis and Photodynamic Therapy
Rui Gao, Xuan Mei, Dongpeng Yan, Ruizheng Liang, Min Wei
Singlet oxygen has won a great deal of attention to catalysis and biological studies due to its strong oxidizing properties. However, the photosensitizers which require for the generation of singlet oxygen remain inadequate because of their lack of long-wavelength absorption, weak hydrophilicity, and poor biocompatibility. Here, we develop near-infrared laser activated supramolecular photosensitizers (isophthalic acid/layered double hydroxide nanohybrids) for efficient two-photon photodynamic therapy. The singlet oxygen quantum yield of nanohybrid is up to 0...
July 18, 2018: Nature Communications
Richard Daubriac, Emmanuel Scheid, Hiba Rizk, Richard Monflier, Sylvain Joblot, Rémi Beneyton, Pablo Acosta Alba, Sébastien Kerdilès, Filadelfo Cristiano
In this paper, we present an enhanced differential Hall effect measurement method (DHE) for ultrathin Si and SiGe layers for the investigation of dopant activation in the surface region with sub-nanometre resolution. In the case of SiGe, which constitutes the most challenging process, we show the reliability of the SC1 chemical solution (NH4 OH/H2 O2 /H2 O) with its slow etch rate, stoichiometry conservation and low roughness generation. The reliability of a complete DHE procedure, with an etching step as small as 0...
2018: Beilstein Journal of Nanotechnology
H Akbar, X Duan, R Piatt, S Saleem, A K Davis, N N Tandon, W Bergmeier, Y Zheng
BACKGROUND: Platelets from patients with X-linked chronic granulomatous disease or mice deficient in NADPH oxidase isoform NOX2 exhibit diminished reactive oxygen species (ROS) generation and platelet activation. Binding of Rac1 GTPase to p67phox plays a critical role in NOX2 activation by facilitating the assembly of the NOX2 enzyme complex. OBJECTIVE: We tested the hypothesis that Phox-I, a rationally designed small molecule inhibitor of Rac-p67phox interaction, may serve as an anti-thrombosis agent by suppressing ROS production and platelet activation...
July 14, 2018: Journal of Thrombosis and Haemostasis: JTH
Jian Xu, Zhuang Wu, Huabin Wan, Guohai Deng, Bo Lu, André K Eckhardt, Peter R Schreiner, Tarek Trabelsi, Joseph S Francisco, Xiaoqing Zeng
Arylsulfinyl radicals are key intermediates in sulfoxide chemistry. The parent molecule, phenylsulfinyl radical PhSO•, has been generated for the first time in the gas phase through high-vacuum flash pyrolysis of PhS(O)R (R = CF3 and Cl) at about 1000 K. Upon UV light irradiation (365 nm), PhSO• isomerizes to novel oxathiyl radical PhOS• in cryogenic matrices (2.8 K). Prolonged irradiation causes further isomerization of PhOS• to 2-hydroxyphenylthiyl radical, the formation of which has been also observed in the 193 nm laser photolysis of matrix-isolated 2-hydroxybenzenethiol...
July 25, 2018: Journal of the American Chemical Society
Mihaela Balas, Florian Dumitrache, Madalina Andreea Badea, Claudiu Fleaca, Anca Badoi, Eugenia Tanasa, Anca Dinischiotu
Magnetic nanoparticles offer multiple utilization possibilities in biomedicine. In this context, the interaction with cellular structures and their biological effects need to be understood and controlled for clinical safety. New magnetic nanoparticles containing metallic/carbidic iron and elemental silicon phases were synthesized by laser pyrolysis using Fe(CO)₅ vapors and SiH₄ gas as Fe and Si precursors, then passivated and coated with biocompatible agents, such as l-3,4-dihydroxyphenylalanine (l-DOPA) and sodium carboxymethyl cellulose (CMC-Na)...
July 5, 2018: Nanomaterials
Daniel Subervie, Bernadette Graff, Swapnil Nerkar, Dennis P Curran, Jacques Lalevée, Emmanuel Lacôte
1,3-Dimethylimidazol-2-ylidene difluoroborane (NHC-BF2 H) was prepared in a one-pot, two-step reaction from the parent ligated borane (NHC-BH3 ). The derived difluoroboryl radical (NHC-BF2 . ) was generated by laser flash photolysis experiments and characterized by UV spectroscopy and rate-constant measurements. It is transient and reacts quickly with O2 . Unusually, it also reacts more rapidly with ethyl vinyl ether than with methyl acrylate. By this measure, it is the first electrophilic ligated boryl radical...
June 21, 2018: Angewandte Chemie
Juan Paolo S Bermundo, Yasuaki Ishikawa, Mami N Fujii, Hiroshi Ikenoue, Yukiharu Uraoka
The emphasis on ubiquitous technology means that future technological applications will depend heavily on transparent conducting materials. To facilitate truly ubiquitous applications, transparent conductors should be fabricated at low temperatures (<50 °C). Here, we demonstrate an instantaneous (<100 ns) and low-temperature (<45 °C at the substrate) method, excimer laser irradiation, for the transformation of an a-InGaZnO semiconductor into a transparent highly conductive oxide with performance rivaling traditional and emerging transparent conductors...
July 25, 2018: ACS Applied Materials & Interfaces
Ruquan Ye, Dustin K James, James M Tour
Research on graphene abounds, from fundamental science to device applications. In pursuit of complementary morphologies, formation of graphene foams is often preferred over the native two-dimensional (2D) forms due to the higher available area. Graphene foams have been successfully prepared by several routes including chemical vapor deposition (CVD) methods and by wet-chemical approaches. For these methods, one often needs either high temperature furnaces and highly pure gases or large amounts of strong acids and oxidants...
July 17, 2018: Accounts of Chemical Research
Xiangling Tian, Hongyu Luo, Rongfei Wei, Chunhui Zhu, Qianyi Guo, Dandan Yang, Fengqiu Wang, Jianfeng Li, Jianrong Qiu
Pulsed lasers operating in the mid-infrared (3-25 µm) are increasingly becoming the light source of choice for a wide range of industrial and scientific applications such as spectroscopy, biomedical research, sensing, imaging, and communication. Up to now, one of the factors limiting the mid-infrared pulsed lasers is the lack of optical switch with a capability of pulse generation, especially for those with wideband response. Here, a semiconductor material of bismuth oxyselenide (Bi2 O2 Se) with a facile processibility, constituting an ultrabroadband saturable absorber for the mid-infrared (actually from the near-infrared to mid-infrared: 0...
June 19, 2018: Advanced Materials
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