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https://www.readbyqxmd.com/read/28806693/persistence-of-urban-organic-aerosols-composition-decoding-their-structural-complexity-and-seasonal-variability
#1
João T V Matos, Regina M B O Duarte, Sónia P Lopes, Artur M S Silva, Armando C Duarte
Organic Aerosols (OAs) are typically defined as highly complex matrices whose composition changes in time and space. Focusing on time vector, this work uses two-dimensional nuclear magnetic resonance (2D NMR) techniques to examine the structural features of water-soluble (WSOM) and alkaline-soluble organic matter (ASOM) sequentially extracted from fine atmospheric aerosols collected in an urban setting during cold and warm seasons. This study reveals molecular signatures not previously decoded in NMR-related studies of OAs as meaningful source markers...
August 11, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28806068/in-situ-atomic-scale-studies-of-the-formation-of-epitaxial-pt-nanocrystals-on-monolayer-molybdenum-disulfide
#2
Shanshan Wang, Hidetaka Sawada, Qu Chen, Grace G D Han, Christopher Allen, Angus I Kirkland, Jamie H Warner
Pt-nanocrystal:MoS2 hybrid materials have promising catalytic properties for hydrogen evolution, and understanding their detailed structures at the atomic scale is crucial to further development. Here, we use an in situ heating holder in an aberration-corrected transmission electron microscope to study the formation of Pt nanocrystals directly on the surface of monolayer MoS2 from a precursor on heating to 800 °C. Isolated single Pt atoms and small nanoclusters are observed after in situ heating, with two types of preferential alignment between the Pt nanocrystals and the underlying monolayer MoS2...
August 14, 2017: ACS Nano
https://www.readbyqxmd.com/read/28805940/new-and-current-preventive-treatment-options-in-actinic-keratosis
#3
REVIEW
P Arenberger, M Arenbergerova
Actinic keratosis (AK) is a characteristic skin lesion on skin areas of subjects with mainly phototype I and phototype II, or with specific genetic factors and who are exposed to prolonged ultraviolet radiation. AK may be considered a precursor of in situ squamous cell carcinoma (SCC), a type of non-melanoma skin cancer (NMSC). However, it is still not possible to predict which AK lesions will develop into SCC. Early treatment of AK is therefore recommended. Despite the increasing number of patients with AK developing into SCC, to date, there is still no clear suggestion of therapeutic strategy for AK...
September 2017: Journal of the European Academy of Dermatology and Venereology: JEADV
https://www.readbyqxmd.com/read/28805876/few-layered-mos2-c-with-expanding-d-spacing-as-a-high-performance-anode-for-sodium-ion-batteries
#4
Peng Zhang, Furong Qin, Lei Zou, Mengran Wang, Kai Zhang, Yanqing Lai, Jie Li
Sodium-ion batteries (SIBs) show great potential as alternative energy storage devices for next generation energy storage systems due to the deficiency of lithium resources. MoS2 is a promising anode material for SIBs due to its high theoretical sodium storage capability and large interspace for accommodating sodium ions with a larger ionic radius than lithium ions. However, bulk MoS2 exhibits a sluggish kinetics for the intercalation-deintercalation of sodium ions and large volume expansion, which result in poor cyclability and rate performance...
August 14, 2017: Nanoscale
https://www.readbyqxmd.com/read/28805845/total-syntheses-of-gerberinol-i-and-the-pterophyllins-2-and-4-using-the-casnati-skatteb%C3%A3-l-reaction-under-different-conditions
#5
Jorgelina L Pergomet, Andrea B J Bracca, Teodoro S Kaufman
The concise and efficient total syntheses of the naturally-occurring coumarin derivatives gerberinol I, and the pterophyllins 2 and 4, from 5-methyl-4-hydroxycoumarin as a common precursor employing different Casnati-Skattebøl reaction conditions, are reported. The synthesis of the key intermediate coumarin was achieved by the organocatalytic condensation of acetylacetone and crotonaldehyde followed by a LiCl-assisted cyclization, CuCl2-promoted aromatization and a final Et2CO3-mediated cyclization. A Casnati-Skattebøl formylation under high-temperature conditions afforded gerberinol I, whereas milder conditions resulted in an unstable 3-formyl-4-hydroxycoumarin derivative, which was subjected to a basic alumina-mediated one pot O-alkylation with chloroacetone and intramolecular aldolization to furnish pterophyllin 4...
August 14, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28805830/in-vitro-and-in-vivo-analysis-of-visible-light-crosslinkable-gelatin-methacryloyl-gelma-hydrogels
#6
Iman Noshadi, Seonki Hong, Kelly E Sullivan, Ehsan Shirzaei Sani, Roberto Portillo-Lara, Ali Tamayol, Su Ryon Shin, Albert E Gao, Whitney L Stoppel, Lauren D Black Iii, Ali Khademhosseini, Nasim Annabi
Photocrosslinkable materials have been frequently used for constructing soft and biomimetic hydrogels for tissue engineering. Although ultraviolet (UV) light is commonly used for photocrosslinking such materials, its use has been associated with several biosafety concerns such as DNA damage, accelerated aging of tissues, and cancer. Here we report an injectable visible light crosslinked gelatin-based hydrogel for myocardium regeneration. Mechanical characterization revealed that the compressive moduli of the engineered hydrogels could be tuned in the range of 5-56 kPa by changing the concentrations of the initiator, co-initiator and co-monomer in the precursor formulation...
August 14, 2017: Biomaterials Science
https://www.readbyqxmd.com/read/28805740/adp-ribosyl-n%C3%A2-a-versatile-precursor-for-divergent-syntheses-of-adp-ribosylated-compounds
#7
Lingjun Li, Qianqian Li, Shengqiang Ding, Pengyang Xin, Yuqin Zhang, Shenlong Huang, Guisheng Zhang
Adenosine diphosphate-ribose (ADP-ribose) and its derivatives play important roles in a series of complex physiological procedures. The design and synthesis of artificial ADP-ribosylated compounds is an efficient way to develop valuable chemical biology tools and discover new drug candidates. However, the synthesis of ADP-ribosylated compounds is currently difficult due to structural complexity, easily broken pyrophosphate bond and high hydrophilicity. In this paper, ADP-ribosyl-N₃ was designed and synthesized for the first time...
August 14, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28805722/estrogen-repression-of-micrornas-is-associated-with-high-guanine-content-in-the-terminal-loop-sequences-of-their-precursors
#8
Amit Cohen, Mario Alberto Burgos-Aceves, Tamar Kahan, Yoav Smith
Widespread microRNA (miRNA) repression is a phenomenon observed in mammals after exposure to cigarette smoke and in many types of cancer. A comprehensive reduction in miRNA expression after treatment with the hormone estrogen has also previously been described. Here, we reveal a conserved association of miRNA downregulation after estrogen exposure in zebrafish, mouse, and human breast cancer cell line, with a high guanine content in the terminal loop sequences of their precursors, and offer a possible link between estrogen-related miRNA-adducts formation and carcinogenesis...
August 14, 2017: Biomedicines
https://www.readbyqxmd.com/read/28805690/preparation-of-magnetic-nanoparticles-via-a-chemically-induced-transition-role-of-treating-solution-s-temperature
#9
Ting Zhang, Xiangshen Meng, Zhenghong He, Yueqiang Lin, Xiaodong Liu, Decai Li, Jian Li, Xiaoyan Qiu
Using FeOOH/Mg(OH)₂ as precursor and FeCl₂ as the treating solution, we prepared γ-Fe₂O₃ based nanoparticles. The FeCl₂ treating solution catalyzes the chemical reactions, dismutation and oxygenation, leading to the formation of products FeCl₃ and Fe₂O₃, respectively. The treating solution (FeCl₂) accelerates dehydration of the FeOOH compound in the precursor and transforms it into the initial seed crystallite γ-Fe₂O₃. Fe₂O₃ grows epitaxially on the initial seed crystallite γ-Fe₂O₃...
August 12, 2017: Nanomaterials
https://www.readbyqxmd.com/read/28805658/nanofibrous-photocatalysts-from-electrospun-nanocapsules
#10
Shuai Jiang, Ingo Lieberwirth, Katharina Landfester, Rafael Munoz-Espi, Daniel Crespy
We present the design of multicompartment metal oxide/silica nanofibrous photocatalysts by colloid-electrospinning and subsequent calcination. During the calcination process, silica nanomaterials are cemented to form the fibrous framework and metal oxide precursors are crystallized inside and onto the fibers. This multicompartment nanofibrous structure, constructed with nanoparticles and core-shell nanocapsules, is therefore beneficial for the separation of the materials and the light utilization due to the multiple reflections and scattering of incident light in the cavities...
August 14, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28805657/noble-metal-free-tungsten-oxide-carbon-wox-c-hybrid-nanowires-for-highly-efficient-hydrogen-evolution
#11
Changhai Liu, Yangyang Qiu, Yujian Xia, Fang Wang, Xiaocun Liu, Xuhui Jeff Sun, Qian Liang, Zhidong Chen
Developing active, stable, and low-cost electrocatalysts to generate hydrogen is a great challenge in the fields of chemistry and energy. The nonprecious metal catalysts comprised of inexpensive and earth-abundant transition metals, regarded as promising substitute for noble metal catalysts used in hydrogen evolution reaction (HER), are still practically unfeasible mainly due to unsatisfactory activity and durability. Here we report the facile two-step preparation method for WOx nanowires with high concentration of oxygen vacancies (OVs) via calcination of W-polydopamine compound precursors...
August 14, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28805652/alloy-multilayers-and-ternary-nanostructures-by-direct-write-approach
#12
Fabrizio Porrati, Roland Sachser, Gian Carlo Gazzadi, Stefano Frabboni, Andreas Terfort, Michael Huth
The fabrication of nanopatterned multilayers, as used in optical and magnetic applications, is usually achieved by two independent steps, which consist in the preparation of multilayer films and in the successive patterning by means of lithography and etching processes. Here we show that multilayer nanostructures can be fabricated by using focused electron beam induced deposition (FEBID), which allows the direct writing of nanostructures of any desired shape with nanoscale resolution. In particular, [Co2Fe=Si]n multilayers are prepared by the alternating deposition from the metal carbonyl precursors, HFeCo3(CO)12 and Fe(CO)5, and neopentasilane, Si5H12...
August 14, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28805615/prenatal-diagnosis-of-holoprosencephaly-associated-with-smith-lemli-opitz-syndrome-slos-in-a-46-xx-fetus
#13
André Travessa, Patrícia Dias, Pedro Rocha, Ana Berta Sousa
OBJECTIVE: To show the importance of measuring cholesterol precursor levels in amniotic fluid in all pregnancies with ultrasound features (such as holoprosencephaly) suggestive of Smith-Lemli-Opitz syndrome (SLOS), after exclusion of chromosomal anomalies. CASE REPORT: A 28-year-old woman, gravida 1 para 0, performed chorionic villus sampling for fetal karyotyping at 13 weeks of gestation due to positive combined first trimester screening in a fetus with increased nuchal translucency and suspected holoprosencephaly...
August 2017: Taiwanese Journal of Obstetrics & Gynecology
https://www.readbyqxmd.com/read/28805558/oxytocin-modulates-expression-of-neuron-and-glial-markers-in-the-rat-hippocampus
#14
T Havránek, Z Lešťanová, B Mravec, V Štrbák, J Bakoš, Z Bačová
Neuropeptides including oxytocin belong to the group of factors that may play a role in the control of neuronal cell survival, proliferation and differentiation. The aim of the present study was to investigate potential contribution of oxytocin to neuronal differentiation by measuring gene and protein expression of specific neuron and glial markers in the brain. Neonatal and adult oxytocin administration was used to reveal developmental and/or acute effects of oxytocin in Wistar rats. Gene and protein expression of neuron-specific enolase (NSE) in the hippocampus was increased in 21-day and 2-month old rats in response to neonatal oxytocin administration...
2017: Folia Biologica (Praha)
https://www.readbyqxmd.com/read/28805394/high-efficiently-delaminated-single-layered-mxene-nanosheets-with-large-lateral-size
#15
Gengnan Li, Li Tan, Yumeng Zhang, Binghan Wu, Liang Li
Single layered Ti3C2(OH)2 nanosheets have been successfully fabricated by etching its Ti3AlC2 precursor with KOH in the presence of small amount of water. The OH group replaced the Al layer within Ti3AlC2 structure during etching process and Ti3C2(OH)2 nanosheets could be easily and efficiently achieved through a simple washing process. The delaminated single layered nanosheets are clearly revealed by atomic force microscopy to have several micrometers in lateral size. Interestingly, the exfoliated Ti3C2(OH)2 nanosheets could be restacked to form a new layer-structured material during drying process...
August 14, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28805371/wavelength-resolved-photon-fluxes-of-indoor-light-sources-implications-for-hox-production
#16
Shawn Finley Kowal, Seth Robert Allen, Tara F Kahan
Photochemistry is a largely-unconsidered potential source of reactive species such as hydroxyl and peroxy radicals (OH and HO2, "HOx") indoors. We present measured wavelength-resolved photon fluxes and distance dependences of indoor light sources including halogen, incandescent, and compact fluorescent lights (CFL) commonly used in residential buildings; fluorescent tubes common in industrial and commercial settings; and sunlight entering buildings through windows. We use these measurements to predict indoor HOx production rates from the photolysis of nitrous acid (HONO), hydrogen peroxide (H2O2), ozone (O3), formaldehyde (HCHO) and acetaldehyde (CH3CHO)...
August 14, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28805260/determination-of-carbon-isotope-enrichment-factors-of-cis-dce-after-precursor-amendment
#17
Simon Leitner, Thomas G Reichenauer, Andrea Watzinger
RATIONALE: Bacterial reductive dechlorination of the groundwater contaminant tetrachloroethene (PCE) involves the formation of lower chlorinated metabolites. Metabolites can be instantaneously formed and consumed in this sequential process; quantification and validation of their isotopic effects conventionally rely on separate laboratory microcosm studies. Here, we present an evaluation method enabling the determination of the carbon isotope enrichment factor (ε) for the intermediate cis-dichloroethene (cis-DCE) by a single laboratory microcosm study initially amending the precursor PCE only...
August 14, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28805227/landscape-of-the-structure-o-h-bond-dissociation-energy-relationship-of-oximes-and-hydroxylamines
#18
Rina Dao, Xinyu Wang, Kexian Chen, Chenxuan Zhao, Jia Yao, Haoran Li
The relationship between the homolytic O-H bond dissociation enthalpies (BDEs) and the structures of N-oxyl radical precursors (i.e. hydroxylamines and oximes) is important to predict their reactivity. Yet several crucial facts remain hidden to complete the picture such as the substituent electronic effects on the BDEs of oximes. In this work, the O-H BDEs of 120 hydroxylamines and 120 oximes have been calculated. It was found that the majority of the iminoxyl radicals are σ radicals, except for some π radicals...
August 14, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28805217/mixed-emulsion-of-liquid-crystal-microresonators-towards-white-laser-systems
#19
Gia Petriashvili, Maria Penelope De Santo, Raul Josue Hernandez, Riccardo Barberi, Gabriella Cipparrone
Microdroplet systems have attracted great interest because of their wide range of applications, easiness in processing and handling, feasibility in developing miniaturized devices with high performances and large flexibility. In this study, a stable emulsion based on different dye-doped chiral liquid crystal droplets has been engineered in order to achieve simultaneous omnidirectional lasing at different wavelengths. To obtain the mixed emulsion of dye doped Bragg onion-type microresonators the twofold action, as a surfactant and a droplet stabilizer, of the polyvinyl alcohol dissolved in water has been exploited...
August 14, 2017: Soft Matter
https://www.readbyqxmd.com/read/28805092/a-review-of-bf-200-ala-for-the-photodynamic-treatment-of-mild-to-moderate-actinic-keratosis
#20
Uwe Reinhold
BF-200 ALA is a combination of a nanoscale-lipid vesicle formulation and the prodrug 5-aminolevulinic acid (5-ALA). The nanoemulsion stabilizes the prodrug and enhances its penetration through the stratum corneum. It has shown excellent therapeutic results in both lesion and field-directed photodynamic therapy of actinic keratosis (AK). AK is an early form of epidermal neoplasia and a precursor of invasive cutaneous squamous cell carcinoma. It is characterized by the combination of visible neoplastic lesions and surrounding tissue also harboring tumorigenic UV-induced mutations: a concept called field cancerization...
August 14, 2017: Future Oncology
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