Showing papers on "Ultraviolet light published in 2015"
TL;DR: Across 234 biopsies of sun-exposed eyelid epidermis from four individuals, the burden of somatic mutations averaged two to six mutations per megabase per cell, similar to that seen in many cancers, and exhibited characteristic signatures of exposure to ultraviolet light.
Abstract: How somatic mutations accumulate in normal cells is central to understanding cancer development but is poorly understood. We performed ultradeep sequencing of 74 cancer genes in small (0.8 to 4.7 square millimeters) biopsies of normal skin. Across 234 biopsies of sun-exposed eyelid epidermis from four individuals, the burden of somatic mutations averaged two to six mutations per megabase per cell, similar to that seen in many cancers, and exhibited characteristic signatures of exposure to ultraviolet light. Remarkably, multiple cancer genes are under strong positive selection even in physiologically normal skin, including most of the key drivers of cutaneous squamous cell carcinomas. Positively selected mutations were found in 18 to 32% of normal skin cells at a density of ~140 driver mutations per square centimeter. We observed variability in the driver landscape among individuals and variability in the sizes of clonal expansions across genes. Thus, aged sun-exposed skin is a patchwork of thousands of evolving clones with over a quarter of cells carrying cancer-causing mutations while maintaining the physiological functions of epidermis.
1,312 citations
TL;DR: A fundamental understanding of energy transfer in lanthanide-supported photon upconversion is presented and the emerging progress in excitation selection based on the energy transfer within lanthanides ions or activation from antennae is introduced.
Abstract: Lanthanide pairs, which can upconvert low energy photons into higher energy photons, are promising for efficient upconversion emission. A typical system with Yb3+ as a sensitizer can convert short NIR into visible/ultraviolet light via energy transfer between lanthanide ions. Such upconverting nanocrystals doped with lanthanide ions have found significant potential in bioimaging, photochemical reactions and energy conversion. This review presents a fundamental understanding of energy transfer in lanthanide-supported photon upconversion. We introduce the emerging progress in excitation selection based on the energy transfer within lanthanide ions or activation from antennae, with an outlook in the development and applications of the lanthanide upconversion emissions.
809 citations
TL;DR: Specific monomer compositions give polymers that are robust and effective photocatalysts for the evolution of hydrogen from water in the presence of a sacrificial electron donor, without the apparent need for an added metal cocatalyst.
Abstract: Photocatalytic hydrogen production from water offers an abundant, clean fuel source, but it is challenging to produce photocatalysts that use the solar spectrum effectively. Many hydrogen-evolving photocatalysts are active in the ultraviolet range, but ultraviolet light accounts for only 3% of the energy available in the solar spectrum at ground level. Solid-state crystalline photocatalysts have light absorption profiles that are a discrete function of their crystalline phase and that are not always tunable. Here, we prepare a series of amorphous, microporous organic polymers with exquisite synthetic control over the optical gap in the range 1.94-2.95 eV. Specific monomer compositions give polymers that are robust and effective photocatalysts for the evolution of hydrogen from water in the presence of a sacrificial electron donor, without the apparent need for an added metal cocatalyst. Remarkably, unlike other organic systems, the best performing polymer is only photoactive under visible rather than ultraviolet irradiation.
685 citations
TL;DR: It is shown that precursors of ribonucleotides, amino acids and lipids can all be derived by the reductive homologation of hydrogen cyanide and some of its derivatives, and thus that all the cellular subsystems could have arisen simultaneously through common chemistry.
Abstract: A minimal cell can be thought of as comprising informational, compartment-forming and metabolic subsystems. To imagine the abiotic assembly of such an overall system, however, places great demands on hypothetical prebiotic chemistry. The perceived differences and incompatibilities between these subsystems have led to the widely held assumption that one or other subsystem must have preceded the others. Here we experimentally investigate the validity of this assumption by examining the assembly of various biomolecular building blocks from prebiotically plausible intermediates and one-carbon feedstock molecules. We show that precursors of ribonucleotides, amino acids and lipids can all be derived by the reductive homologation of hydrogen cyanide and some of its derivatives, and thus that all the cellular subsystems could have arisen simultaneously through common chemistry. The key reaction steps are driven by ultraviolet light, use hydrogen sulfide as the reductant and can be accelerated by Cu(I)–Cu(II) photoredox cycling. A minimal cell — one that has all the minimum requirements for life — is still a complex entity comprising informational, compartment-forming and metabolic subsystems. Here it is shown that, contrary to previous assumptions, a common prebiotically plausible chemistry can give rise to building blocks for all the subsystems.
655 citations
TL;DR: It is concluded that TNT-mediated transfer of functional mitochondria reverse stressed cells in the early stages of apoptosis provides new insights into the survival mechanisms of damaged cells in a multicellular context.
Abstract: Tunneling nanotubes (TNTs) are F-actin-based membrane tubes that form between cells in culture and in tissues. They mediate intercellular communication ranging from electrical signalling to the transfer of organelles. Here, we studied the role of TNTs in the interaction between apoptotic and healthy cells. We found that pheochromocytoma (PC) 12 cells treated with ultraviolet light (UV) were rescued when cocultured with untreated PC12 cells. UV-treated cells formed a different type of TNT with untreated PC12 cells, which was characterized by continuous microtubule localized inside these TNTs. The dynamic behaviour of mCherry-tagged end-binding protein 3 and the accumulation of detyrosinated tubulin in these TNTs indicate that they are regulated structures. In addition, these TNTs show different biophysical properties, for example, increased diameter allowing dye entry, prolonged lifetime and decreased membrane fluidity. Further studies demonstrated that microtubule-containing TNTs were formed by stressed cells, which had lost cytochrome c but did not enter into the execution phase of apoptosis characterized by caspase-3 activation. Moreover, mitochondria colocalized with microtubules in TNTs and transited along these structures from healthy to stressed cells. Importantly, impaired formation of TNTs and untreated cells carrying defective mitochondria were unable to rescue UV-treated cells in the coculture. We conclude that TNT-mediated transfer of functional mitochondria reverse stressed cells in the early stages of apoptosis. This provides new insights into the survival mechanisms of damaged cells in a multicellular context.
319 citations
TL;DR: A new route to form anti-fouling steel surfaces by electrodeposition of nanoporous tungsten oxide (TO) films is reported, which is as mechanically durable as bare steel and highly tolerant to compressive and tensile stresses due to chemical bonding to the substrate and island-like morphology.
Abstract: Formation of unwanted deposits on steels during their interaction with liquids is an inherent problem that often leads to corrosion, biofouling and results in reduction in durability and function. Here we report a new route to form anti-fouling steel surfaces by electrodeposition of nanoporous tungsten oxide (TO) films. TO-modified steels are as mechanically durable as bare steel and highly tolerant to compressive and tensile stresses due to chemical bonding to the substrate and island-like morphology. When inherently superhydrophilic TO coatings are converted to superhydrophobic, they remain non-wetting even after impingement with yttria-stabilized-zirconia particles, or exposure to ultraviolet light and extreme temperatures. Upon lubrication, these surfaces display omniphobicity against highly contaminating media retaining hitherto unseen mechanical durability. To illustrate the applicability of such a durable coating in biofouling conditions, we modified naval construction steels and surgical instruments and demonstrated significantly reduced marine algal film adhesion, Escherichia coli attachment and blood staining.
310 citations
TL;DR: It is shown that photothermal effect of H‐TiO2 NPs can be attributed to their dramatically enhanced nonradiative recombination, and they exhibit low toxicity, high efficiency as a photothermal agent for cancer therapy, and are promising for further biomedical applications.
Abstract: White TiO2 nanoparticles (NPs) have been widely used for cancer photodynamic therapy based on their ultraviolet light-triggered properties. To date, biomedical applications using white TiO2 NPs have been limited, since ultraviolet light is a well-known mutagen and shallow penetration. This work is the first report about hydrogenated black TiO2 (H-TiO2 ) NPs with near infrared absorption explored as photothermal agent for cancer photothermal therapy to circumvent the obstacle of ultraviolet light excitation. Here, it is shown that photothermal effect of H-TiO2 NPs can be attributed to their dramatically enhanced nonradiative recombination. After polyethylene glycol (PEG) coating, H-TiO2 -PEG NPs exhibit high photothermal conversion efficiency of 40.8%, and stable size distribution in serum solution. The toxicity and cancer therapy effect of H-TiO2 -PEG NPs are relative systemically evaluated in vitro and in vivo. The findings herein demonstrate that infrared-irradiated H-TiO2 -PEG NPs exhibit low toxicity, high efficiency as a photothermal agent for cancer therapy, and are promising for further biomedical applications.
294 citations
TL;DR: In this article, the authors show that UV-caused chlamydia trachomatis infection induces a long-lived protection in conventional and humanized mice, using charge switching synthetic adjuvant particles (cSAPs).
Abstract: Genital Chlamydia trachomatis (Ct) infection induces protective immunity that depends on interferon-γ-producing CD4 T cells. By contrast, we report that mucosal exposure to ultraviolet light (UV)-inactivated Ct (UV-Ct) generated regulatory T cells that exacerbated subsequent Ct infection. We show that mucosal immunization with UV-Ct complexed with charge-switching synthetic adjuvant particles (cSAPs) elicited long-lived protection in conventional and humanized mice. UV-Ct-cSAP targeted immunogenic uterine CD11b(+)CD103(-) dendritic cells (DCs), whereas UV-Ct accumulated in tolerogenic CD11b(-)CD103(+) DCs. Regardless of vaccination route, UV-Ct-cSAP induced systemic memory T cells, but only mucosal vaccination induced effector T cells that rapidly seeded uterine mucosa with resident memory T cells (T(RM) cells). Optimal Ct clearance required both T(RM) seeding and subsequent infection-induced recruitment of circulating memory T cells. Thus, UV-Ct-cSAP vaccination generated two synergistic memory T cell subsets with distinct migratory properties.
288 citations
TL;DR: In this article, the microstructure and phase composition of these composites were characterized by field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD).
205 citations
TL;DR: Solid-state luminescent properties of the new solvent-induced metal-organic frameworks showed high selectivity and sensitivity for Cu(2+) ions and nitrobenzene because of the quenching effect, which thus could make it a potential crystalline material for detecting these substances.
Abstract: Three new solvent-induced metal–organic frameworks (MOFs)—[Cd(H2L)(H2O)3]·NMP (1), [Cd3(L)(H2O)4(OH)2] (2) and [Cd(L)0.5(H2O)]·H2O (3)—were designed and successfully prepared via solvothermal reaction by multidentate phenyltetracarboxylic acid [1,1′:4′,1′′-terphenyl]-2′,3,3′′,5′-tetracarboxylic acid (H4L) and Cd(II) salts in various solvent systems. Structural analyses indicated that the H2L/L ligands took three different coordination fashions in 1–3, and thus resulted in diversity of the targeted MOFs. Solid-state luminescent properties of the three MOFs were studied under ultraviolet light irradiation at ambient temperature; 3 in particular showed high selectivity and sensitivity for Cu2+ ions and nitrobenzene because of the quenching effect, which thus could make it a potential crystalline material for detecting these substances. The mechanisms of the quenching effect and sensing properties of 3 are discussed in detail.
199 citations
TL;DR: It is demonstrated that the chia mucilage hydrocolloid has important properties and potential as an edible film, or coating.
TL;DR: By carefully tuning the synthesis conditions, a record IQE of 80% can be realized with N-polar AlN nanowire LEDs with emission wavelengths covering the UV-B/C bands, which is nearly ten times higher compared to high quality planar AlN.
Abstract: Despite broad interest in aluminum gallium nitride (AlGaN) optoelectronic devices for deep ultraviolet (DUV) applications, the performance of conventional Al(Ga)N planar devices drastically decays when approaching the AlN end, including low internal quantum efficiencies (IQEs) and high device operation voltages. Here we show that these challenges can be addressed by utilizing nitrogen (N) polar Al(Ga)N nanowires grown directly on Si substrate. By carefully tuning the synthesis conditions, a record IQE of 80% can be realized with N-polar AlN nanowires, which is nearly ten times higher compared to high quality planar AlN. The first 210 nm emitting AlN nanowire light emitting diodes (LEDs) were achieved, with a turn on voltage of about 6 V, which is significantly lower than the commonly observed 20 – 40 V. This can be ascribed to both efficient Mg doping by controlling the nanowire growth rate and N-polarity induced internal electrical field that favors hole injection. In the end, high performance N-polar AlGaN nanowire LEDs with emission wavelengths covering the UV-B/C bands were also demonstrated.
TL;DR: Genetic alterations in specific pathways in MF were identified that may be viable, effective new targets for treatment and identified 2 other potential contributing factors to MF, ultraviolet light, and a polymorphism in the tumor suppressor p53.
TL;DR: The whole genome mutation profiles of mouse embryo fibroblasts immortalised following exposure to benzo[a]pyrene (BaP), ultraviolet light (UV) and aristolochic acid (AA) reveal that each mutagen induces a characteristic mutation signature.
Abstract: Whole genome sequencing of human tumours has revealed distinct patterns of mutation that hint at the causative origins of cancer. Experimental investigations of the mutations and mutation spectra induced by environmental mutagens have traditionally focused on single genes. With the advent of faster cheaper sequencing platforms, it is now possible to assess mutation spectra in experimental models across the whole genome. As a proof of principle, we have examined the whole genome mutation profiles of mouse embryo fibroblasts immortalised following exposure to benzo[a]pyrene (BaP), ultraviolet light (UV) and aristolochic acid (AA). The results reveal that each mutagen induces a characteristic mutation signature: predominantly G→T mutations for BaP, C→T and CC→TT for UV and A→T for AA. The data are not only consistent with existing knowledge but also provide additional information at higher levels of genomic organisation. The approach holds promise for identifying agents responsible for mutations in human tumours and for shedding light on the aetiology of human cancer.
TL;DR: Main mechanisms of actions of these compounds in the chemoprevention of these cancers include suppression of cell proliferation, induction of apoptosis, stimulation of antimetastatic and antiangiogenic responses and increased antioxidant and anti-inflammatory activity.
Abstract: The risk of onset of cancer is influenced by poorly controlled chronic inflammatory processes. Inflammatory diseases related to cancer development include inflammatory bowel disease, which can lead to colon cancer, or actinic keratosis, associated with chronic exposure to ultraviolet light, which can progress to squamous cell carcinoma. Chronic inflammatory states expose these patients to a number of signals with tumorigenic effects, including nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPK) activation, pro-inflammatory cytokines and prostaglandins release and ROS production. In addition, the participation of inflammasomes, autophagy and sirtuins has been demonstrated in pathological processes such as inflammation and cancer. Chemoprevention consists in the use of drugs, vitamins, or nutritional supplements to reduce the risk of developing or having a recurrence of cancer. Numerous in vitro and animal studies have established the potential colon and skin cancer chemopreventive properties of substances from marine environment, including microalgae species and their products (carotenoids, fatty acids, glycolipids, polysaccharides and proteins). This review summarizes the main mechanisms of actions of these compounds in the chemoprevention of these cancers. These actions include suppression of cell proliferation, induction of apoptosis, stimulation of antimetastatic and antiangiogenic responses and increased antioxidant and anti-inflammatory activity.
TL;DR: In this article, the first successful attempt for the synthesis of nanocrystalline praseodymium oxide by using poly ethylene glycol (PEG) via a simple precipitation route in the presence of Trien was made.
Abstract: Nanocrystalline praseodymium oxide was prepared by a novel facile precipitation route via reaction of praseodymium nitrate and triethylenetetramine (Trien) as a new precipitating agent in the presence of poly ethylene glycol (PEG). To the best of our knowledge, this work is the first successful attempt for the synthesis of nanocrystalline praseodymium oxide by using PEG via a simple precipitation route in the presence of Trien. To investigate the effect of the amount of Trien on the morphology and particle size of praseodymium oxide, several experiments were carried out. Based on the experimental findings of this research, it was found that this parameter has an important impact on the morphology and particle size of the products. The structural, morphological and optical properties of the as-obtained products were characterized by techniques such as Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray microanalysis (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) spectroscopy, and photoluminescence (PL) spectroscopy. To evaluate the catalytic properties of nanocrystalline praseodymium oxide, the photocatalytic degradation of 2-naphthol under ultraviolet light irradiation was carried out.
TL;DR: In this article, the first demonstration of high-conversion-rate photochemical reduction of carbon dioxide (CO2) on gallium nitride (GaN) nanowire arrays into methane (CH4) and carbon monoxide (CO).
Abstract: We report on the first demonstration of high-conversion-rate photochemical reduction of carbon dioxide (CO2) on gallium nitride (GaN) nanowire arrays into methane (CH4) and carbon monoxide (CO). It was observed that the reduction of CO2 to CO dominates on as-grown GaN nanowires under ultraviolet light irradiation. However, the production of CH4 is significantly increased by using the Rh/Cr2O3 core/shell cocatalyst, with an average rate of ∼3.5 μmol gcat–1 h–1 in 24 h. In this process, the rate of CO2 to CO conversion is suppressed by nearly an order of magnitude. The rate of photoreduction of CO2 to CH4 can be further enhanced and can reach ∼14.8 μmol gcat–1 h–1 by promoting Pt nanoparticles on the lateral m-plane surfaces of GaN nanowires, which is nearly an order of magnitude higher than that measured on as-grown GaN nanowire arrays. This work establishes the potential use of metal-nitride nanowire arrays as a highly efficient photocatalyst for the direct photoreduction of CO2 into chemical fuels. It al...
TL;DR: Overexpression of MYB182 in hairy root culture and whole poplar plants led to reduced PA and anthocyanin levels as well as a reduction in the expression of key flavonoid genes, which shows that MyB182 plays an important role in the fine-tuning of MyB134-mediated flavonoids metabolism.
Abstract: Trees in the genus Populus (poplar) contain phenolic secondary metabolites including the proanthocyanidins (PAs), which help to adapt these widespread trees to diverse environments. The transcriptional activation of PA biosynthesis in response to herbivory and ultraviolet light stress has been documented in poplar leaves, and a regulator of this process, the R2R3-MYB transcription factor MYB134, has been identified. MYB134-overexpressing transgenic plants show a strong high-PA phenotype. Analysis of these transgenic plants suggested the involvement of additional MYB transcription factors, including repressor-like MYB factors. Here, MYB182, a subgroup 4 MYB factor, was found to act as a negative regulator of the flavonoid pathway. Overexpression of MYB182 in hairy root culture and whole poplar plants led to reduced PA and anthocyanin levels as well as a reduction in the expression of key flavonoid genes. Similarly, a reduced accumulation of transcripts of a MYB PA activator and a basic helix-loop-helix cofactor was observed in MYB182-overexpressing hairy roots. Transient promoter activation assays in poplar cell culture demonstrated that MYB182 can disrupt transcriptional activation by MYB134 and that the basic helix-loop-helix-binding motif of MYB182 was essential for repression. Microarray analysis of transgenic plants demonstrated that down-regulated targets of MYB182 also include shikimate pathway genes. This work shows that MYB182 plays an important role in the fine-tuning of MYB134-mediated flavonoid metabolism.
TL;DR: This work describes a hemithioindigo-based molecular motor, which is powered exclusively by nondestructive visible light and rotates completely directionally with kHz frequency at 20 °C, and is the fastest directional motion of a synthetic system driven by visible light to date.
Abstract: Photodriven molecular motors are able to convert light energy into directional motion and hold great promise as miniaturized powering units for future nanomachines. In the current state of the art, considerable efforts have still to be made to increase the efficiency of energy transduction and devise systems that allow operation in ambient and non-damaging conditions with high rates of directional motions. The need for ultraviolet light to induce the motion of virtually all available light-driven motors especially hampers the broad applicability of these systems. We describe here a hemithioindigo-based molecular motor, which is powered exclusively by nondestructive visible light (up to 500 nm) and rotates completely directionally with kHz frequency at 20 °C. This is the fastest directional motion of a synthetic system driven by visible light to date permitting materials and biocompatible irradiation conditions to establish similarly high speeds as natural molecular motors. Although photodriven molecular motors—capable of converting light into unidirectional motion—hold promise for many applications, these typically require ultraviolet light. Here, the authors design and analyse a motor that can operate at high speeds (kHz) under visible light at ambient temperature.
TL;DR: Reducing the function of PAL, the first enzyme in the phenylpropanoid pathway, in Brachypodium distachyon alters cell wall composition, increases fungal susceptibility, but minimally affects caterpillar herbivory and abiotic stress tolerance.
Abstract: The phenylpropanoid pathway in plants synthesizes a variety of structural and defence compounds, and is an important target in efforts to reduce cell wall lignin for improved biomass conversion to biofuels. Little is known concerning the trade-offs in grasses when perturbing the function of the first gene family in the pathway, PHENYLALANINE AMMONIA LYASE (PAL). Therefore, PAL isoforms in the model grass Brachypodium distachyon were targeted, by RNA interference (RNAi), and large reductions (up to 85%) in stem tissue transcript abundance for two of the eight putative BdPAL genes were identified. The cell walls of stems of BdPAL-knockdown plants had reductions of 43% in lignin and 57% in cell wall-bound ferulate, and a nearly 2-fold increase in the amounts of polysaccharide-derived carbohydrates released by thermochemical and hydrolytic enzymic partial digestion. PAL-knockdown plants exhibited delayed development and reduced root growth, along with increased susceptibilities to the fungal pathogens Fusarium culmorum and Magnaporthe oryzae. Surprisingly, these plants generally had wild-type (WT) resistances to caterpillar herbivory, drought, and ultraviolet light. RNA sequencing analyses revealed that the expression of genes associated with stress responses including ethylene biosynthesis and signalling were significantly altered in PAL knocked-down plants under non-challenging conditions. These data reveal that, although an attenuation of the phenylpropanoid pathway increases carbohydrate availability for biofuel, it can adversely affect plant growth and disease resistance to fungal pathogens. The data identify notable differences between the stress responses of these monocot pal mutants versus Arabidopsis (a dicot) pal mutants and provide insights into the challenges that may arise when deploying phenylpropanoid pathway-altered bioenergy crops.
TL;DR: The amplitude and the sinusoid-like shape of the variability of the light curve of PG 1302-102 can be fitted by relativistic Doppler boosting of emission from a compact, steadily accreting, unequal-mass binary, and it is predicted that brightness variations in the ultraviolet light curve track those in the optical, but with a two to three times larger amplitude.
Abstract: Because most large galaxies contain a central black hole, and galaxies often merge, black-hole binaries are expected to be common in galactic nuclei. Although they cannot be imaged, periodicities in the light curves of quasars have been interpreted as evidence for binaries, most recently in PG 1302-102, which has a short rest-frame optical period of four years (ref. 6). If the orbital period of the black-hole binary matches this value, then for the range of estimated black-hole masses, the components would be separated by 0.007-0.017 parsecs, implying relativistic orbital speeds. There has been much debate over whether black-hole orbits could be smaller than one parsec (ref. 7). Here we report that the amplitude and the sinusoid-like shape of the variability of the light curve of PG 1302-102 can be fitted by relativistic Doppler boosting of emission from a compact, steadily accreting, unequal-mass binary. We predict that brightness variations in the ultraviolet light curve track those in the optical, but with a two to three times larger amplitude. This prediction is relatively insensitive to the details of the emission process, and is consistent with archival ultraviolet data. Follow-up ultraviolet and optical observations in the next few years can further test this prediction and confirm the existence of a binary black hole in the relativistic regime.
TL;DR: A potent, inducible, broad-spectrum and vector-based mutagenesis system in E. coli that enhances mutation 322,000-fold over basal levels, surpassing the mutational efficiency and spectra of widely used in vivo and in vitro methods is created.
Abstract: Methods to enhance random mutagenesis in cells offer advantages over in vitro mutagenesis, but current in vivo methods suffer from a lack of control, genomic instability, low efficiency and narrow mutational spectra. Using a mechanism-driven approach, we created a potent, inducible, broad-spectrum and vector-based mutagenesis system in E. coli that enhances mutation 322,000-fold over basal levels, surpassing the mutational efficiency and spectra of widely used in vivo and in vitro methods. We demonstrate that this system can be used to evolve antibiotic resistance in wild-type E. coli in <24 h, outperforming chemical mutagens, ultraviolet light and the mutator strain XL1-Red under similar conditions. This system also enables the continuous evolution of T7 RNA polymerase variants capable of initiating transcription using the T3 promoter in <10 h. Our findings enable broad-spectrum mutagenesis of chromosomes, episomes and viruses in vivo, and are applicable to both bacterial and bacteriophage-mediated laboratory evolution platforms.
TL;DR: In this article, a new simple solvent-less route was used to synthesize Pr6O11 nanostructures via a heat treatment in air at 600 °C for 5 h, using [Pr L(NO3)2]NO3 (L = bis-(2-hydroxy phenyl methyl ketone)-dipropylene triamin Schiff base ligand), as a precursor, which was obtained by a solvent-free solid-solid reaction from different molar ratios of praseodymium nitrate and a Schiff bases ligand.
Abstract: Praseodymium oxide (Pr6O11) nanostructures were prepared via a new simple solvent-less route. The nanostructures were synthesized by a heat treatment in air at 600 °C for 5 h, using [Pr L(NO3)2]NO3 (L = bis-(2-hydroxy phenyl methyl ketone)-dipropylene triamin Schiff base ligand), as a precursor, which was obtained by a solvent-free solid–solid reaction from different molar ratios of praseodymium nitrate and a Schiff base ligand. The as-prepared nanostructures were characterized by means of several techniques including X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray microanalysis (EDX), photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), nuclear magnetic resonance spectroscopy (1H NMR) analysis, UV-vis diffuse reflectance spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. The obtained results showed that the morphology and particle size of the final Pr6O11 could be dramatically affected via the molar ratio of praseodymium nitrate and the Schiff base ligand. The photocatalytic activity of the as-synthesized nanostructures was also investigated by the degradation of 2-naphthol as an organic contaminant under ultraviolet light irradiation.
TL;DR: UV/PS has the potential to minimize the formation of a range of N- DBPs in organic nitrogen-rich waters where N-DBP precursors are prevalent, however, these benefits should be weighed against the potential drawbacks of increased bromate and sulfate formation, particularly in high-bromide waters.
TL;DR: In this paper, pure holmium oxide ceramic nanostructures were synthesized by heat treatment in air at 600°C for 5h, utilizing [Ho L(NO3)2]NO3 (L=bis-(2-hydroxy-1-naphthaldehyde)-butanediamine Schiff base ligand), as a precursor, which was prepared via a solvent-free solid-solid reaction from different molar ratios of Holmium nitrate and Schiff base l ligand.
TL;DR: In this paper, Nb-doped TiO2 porous microspheres prepared by ultrasonic spray pyrolysis of peroxide precursor solution are yellow, and the yellow coloration becomes increasingly conspicuous with increasing Nb dopant concentration.
Abstract: Doping TiO2 photocatalysts with foreign ions has been deemed an effective method to enhance visible light absorption and thus increase their photocatalytic performance. Herein, we report that Nb-doped TiO2 porous microspheres prepared by ultrasonic spray pyrolysis of peroxide precursor solution are yellow, and the yellow coloration becomes increasingly conspicuous with increasing Nb dopant concentration. Comprehensive spectral analyses show that both surface peroxo species and bulk Ti3+ are introduced into TiO2 microsphere samples together by charge compensation with Nb5+ dopant and are responsible for the coloration of TiO2. The Nb-doped microspheres show higher photocatalytic rates than undoped TiO2 for the degradation of gaseous acetaldehyde under visible irradiation but slower rates under ultraviolet light. Moreover, the photocatalytic mineralization rates of acetaldehyde to CO2 are lowered with Nb doping under both visible and UV irradiation. Correlation between the results of surface photovoltage sp...
TL;DR: In this article, the authors investigate the variations of inkjet 3D printed structures by analyzing parameters of the whole process and determine and quantify the parameters that lead to the most accurate geometry and to the best mechanical properties.
TL;DR: The challenges facing UV-induced drug delivery are presented and some of the proposed solutions are presented.
TL;DR: In this article, a silver oxide nanoparticle aggregation with superb photocatalytic performance under artificial light source and sunlight was prepared and characterized, and the results showed that methyl orange (MO) was decomposed completely in 120 s under irradiation of artificial visible light, artificial ultraviolet light, and sunlight, and in 40 min under near infrared (NIR) light.
Abstract: Photocatalytic processes are an environmentally friendly technology for treatment of persistent organic pollutants. However, the majority of current photocatalysts cannot utilize sunlight sufficiently to realize fast decomposition of organic pollutants. In this research, a silver oxide nanoparticle aggregation with superb photocatalytic performance under artificial light source and sunlight was prepared and characterized. The results showed that methyl orange (MO) was decomposed completely in 120 s under irradiation of artificial visible light, artificial ultraviolet light, and sunlight, and in 40 min under near-infrared (NIR) light. The superb photocatalytic performance of as-prepared silver oxide remained almost constant after reuse or exposure under sunlight. It was confirmed that the co-working effect of photogenerated hole and ozone anion radicals did play an important role in the process of MO photodegradation with the existence of Ag2O. The narrow band gap of Ag2O, less than 1.3 eV, resulted in the...
TL;DR: DBP formation potential for THMs, HAAs, HANs, and AOX was observed to increase approximately to the same extent as was observed for pretreatment using the more common AOP of UV combined with hydrogen peroxide (UV/H2O2).