Fluorescent brighteners in thiol-acrylate polymerizations: Sunlight-cured coatings and LED-assisted multifuctional intelligent nanoparticles synthesis

Fluorescent-brightener-mediated thiol-ene reactions under visible-light LED: A green and facile synthesis route to hyperbranched polymers and stimuli-sensitive nanoemulsions

The objective of this study was to determine the sublethal toxicity of TiO 2 nanoparticles (TiO 2 -NPs) on common carp ( Cyprinus carpio ) under visible light and dark conditions. Blood sampled was collected after 21 days and biochemical parameters, including glucose, total protein, albumin, globulin, creatinine, triglyceride and cholesterol levels, and aspartate aminotransferase (AST), alanine aminotransferase (ALT), γ-glutamyl transferase (GGT), lactate dehydrogenase (LDH), creatine kinase (CK), and alkaline phosphatase (ALP) activities were measured. The results showed that TiO 2 -NPs is caused a significant effect on blood biochemical parameters of C. carpio . By changing lighting conditions from darkness to light, significant differences were observed in certain blood biochemical parameters, including AST, ALT, LDH, ALP and CK activities, glucose, cholesterol and triglyceride levels in fish exposed to TiO 2 -NPs under light conditions as compared with fish exposed to TiO 2 -NPs under dark conditions. Cholesterol and triglyceride levels in fish exposed to 0.0 mg L -1 TiO 2 -NPs under darkness conditions were significantly higher than the control. The results revealed that toxicity of TiO 2 -NPs under visible light conditions was more than darkness conditions.

The ubiquitous presence of TiO2 nanoparticles (nTiO2) and microplastics (MPs) in marine ecosystems has raised serious concerns about their combined impact on marine biota. This study investigated the combined toxic effect of nTiO2 (1 mg/L) and NH2 and COOH surface functionalized polystyrene MPs (PSMPs) (2.5 and 10 mg/L) on Chlorella sp. All the experiments were carried out under both visible light and UV-A radiation conditions to elucidate the impact of light on the combined toxicity of these pollutants. Growth inhibition results indicated that pristine nTiO2 exhibited a more toxic effect (38%) under UV-A radiation when compared to visible light conditions (27%). However, no significant change in the growth inhibitory effects of pristine PSMPs was observed between visible light and UVA radiation conditions. The combined pollutants (nTiO2 + 10 mg/L PSMPs) under UV-A radiation exhibited more growth inhibition (nTiO2 + NH2 PSMPs 66%; nTiO2 + COOH PSMPs 50%) than under visible light conditions (nTiO2 + NH2 PSMPs 55%; TiO2 + COOH PSMPs 44%). Independent action modeling indicated that the mixture of nTiO2 with PSMPs (10 mg/L) exhibited an additive effect on the algal growth inhibition under both the light conditions. The photoactive nTiO2 promoted increased production of reactive oxygen species under UV-A exposure, resulting in cellular damage, lipid peroxidation, and impaired photosynthesis. The effects were more pronounced in case of the mixtures where PSMPs added to the oxidative stress. The toxic effects of the binary mixtures of nTiO2 and PSMPs were further confirmed through the field emission electron microscopy, revealing specific morphological abnormalities. This study provides valuable insights into the potential risks associated with the combination of nTiO2 and MPs in marine environments, considering the influence of environmentally relevant light conditions and the test medium.

Event Abstract Back to Event Biodegradable polyanhydrides from thiol-ene polymerizations: fast, robust and reliable curing yields surface eroding materials Katie L. Poetz1, Halimatu S. Mohammed1, Lina Bian1, Sergii Domanskyi2, Vladimir Privman2, Paul J. Goulet1 and Devon Shipp1 1 Clarkson University, Department of Chemistry and Biomolecular Science, United States 2 Clarkson University, Department of Physics, United States Introduction: Polyanhydrides have long been known as surface-eroding biomaterials, and thus have realized their potential in drug-release devices such as the Gliadel Wafer™. However, despite extensive efforts there have been several significant roadblocks to the further application of these materials in the biomedical arena. One of the primary problems is the demanding curing process of the monomers used in the majority of studies since these monomers are often diacids (or their acyl chloride derivatives). Therefore, such reactions need high vacuum and temperatures, rendering in situ curing impossible. We have recently[1][2] shown that thiol-ene radical polymerization is ideally suited for the polymerization of polyanhydrides (Scheme 1). Here we discuss the synthesis, characterization and erosion characteristics of these materials. Materials: 4-Pentenoic anhydride (PNA), 1,6-hexanedithiol (HDT), pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), 1-hydroxycyclohexyl phenyl ketone were purchased from Sigma-Aldrich. Methods: Example synthesis using PNA:HDT:PETMP = 100:70:30 (mole ratios of functional groups): 1-hydroxycyclohexyl phenyl ketone (1.4 mg, 0.0069 mmol, 0.1 wt%), PETMP (0.22 mL, 0.57 mmol), HDT (0.41 mL, 2.68 mmol) and PNA (0.7 mL, 3.83 mmol) were weighed into a small vial. After mixing to establish a homogenous solution it was transferred to a mold for polymerization and irradiated by UV light for 15 minutes. Samples were degraded by placing them into 100 mL of aqueous PBS solution at 37°C. At select time intervals, the polymer was removed from the buffered solution, the surface quickly dried and polymer weighed and new buffer solution added. Results: Thiol-ene polymerizations were photoinitiated using to yield crosslinked polyanhydrides with essentially 100% conversion of thiol and ene groups. The inclusion of HDT at amounts of >60% thiol groups (but <100%) yielded semicrystalline crosslinked polyanhydrides, as determined by differential scanning calorimetry (DSC), which showed crystalline melt temperatures of approximately 60oC, and wide-angle x-ray diffraction. Erosion of these materials showed qualitative surface erosion behavior; with mass-loss curves exhibiting a short induction period (~24 hours) before erosion being compete in around 10 days (Figure 1). Discussion: In comparison with traditional approaches to polyanhydride synthesis, thiol-ene ‘click’ chemistry has many advantages: many monomers are simple and readily available, and there is low susceptibility to oxygen, low shrinkage, and uniform cross-link density. Furthermore, because thiol-ene polymerization occurs via a step-growth mechanism, the degradable anhydride functionality resides in the main chain, rather than a side chain, which reduces the molecular weight of the degradation products compared to biomaterials synthesized by chain growth polymerizations. Initiation can be achieved using purely thermal, redox, or photochemical methods, or some combination of these. We have also found that surface erosion occurs, [1][3] and the materials have very high cytocompatibility, even at elevated concentrations [2][4]. Conclusions: Thiol-ene chemistry can be reliably applied to the rapid production of polyanhydrides that are surface-eroding in aqueous environments, and presents significant opportunities for potentially broad use of these materials in many applications, including biomedical devices, adaptable surfaces, shape memory materials, drug delivery, erodible/resorbable adhesives, self-cleaning surfaces, adaptable and patternable surfaces, functionalized surfaces/particles, hierarchical structures, and scaffolds for cell growth.

Pd/CC catalyst was synthesized from readily available biomass-derived d-glucose. The catalyst was characterized using various techniques such as Fourier transform infrared spectroscopy, powder X-ray diffraction, energy dispersive X-ray analysis, scanning electron microscopy, 13C cross polarization NMR, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller (BET) surface area analysis. This catalyst showed excellent catalytic activity toward the synthesis of industrially important 2,5-furandicarboxylic acid (FDCA) from 5-hydroxymethylfurfural (HMF) and fructose. The process is simple, efficient, green, and industrially feasible. Oxidation of HMF proceeded in 85% yield, and dehydration of fructose followed by oxidation gave 64% yield of FDCA with 100% purity using Pd/CC catalyst and molecular O2 as an oxidizing agent under aqueous reaction conditions. The one pot two step procedure is highly efficient for synthesis of FDCA from fructose as it avoids isolation of HMF a...

Although the modern biological systems are by large based on DNA genomes and protein enzymes, RNA plays important roles in many fundamental processes in cells, including regulation of protein biosynthesis, RNA splicing, and retroviral replication, with remarkable features. From this point of view, site-specific substitution and derivatization of RNA can provide powerful tools for elucidating RNA structures and functions. The modification of either the 3'and 5'-termini or an internal position of the oligonucleotides with a primary alkylamine group is a widely used method for introducing additional functional groups to the RNA. In particular, several 5'-modifications of RNA molecules such as sulfhydryl modification for functionalizing the 5'-terminus of RNA by a transcription or kinase reaction have been shown to have broad applications in studying RNA structures, mapping RNA-protein interactions, and in vitro selection of catalytic RNAs, since a unique functional group incorporated into the RNA can be subsequently conjugated to the desired molecule by a selective chemical reaction. However, there is still a need to develop coupling chemistry with high stability and yield to modify RNA and other biomolecules. In addition, the coupling functional groups are ideally required to be stable under aqueous reaction conditions, and the coupling reaction should be highly chemoselective. In this regard, Cu-catalyzed azide-alkyne cycloaddition (CuAAC or click chemistry) to form the triazole version of Huisgen’s [2+3] cycloaddition family may be the best choice, because this reaction only occurs between alkynyl and azido functional groups with high yield, and because the resulting 1,2,3-triazoles are stable at aqueous conditions and high temperature. Indeed, the azide group is one of the most utilized bioorthogonal chemical tags for biomolecule-conjugate experiments because of its small size and inertness to most components in a biological environment. We recently reported a two-step synthetic method for 5'azido-5'-deoxyguanosine (azido-G) by adapting literature procedures (Scheme 1) and its efficiency for click chemistry using 6-heptynoyl p-nitroaniline, in consideration that the click chemistry with rapid reaction between the azide and alkyne groups to form a covalent triazole linkage without cross reacting with other functional groups could be used in bioconjugation chemistry. In the present study, we sought enzymatic methods to incorporate azido groups in RNA and measured incorporation efficiency of azido-G into the 5'terminus of RNA by in vitro transcription using T7 RNA polymerase that requires guanosine to efficiently initiate transcription. This is important in consideration that a terminal azido group is able to be introduced to the 5'termini of RNA molecules, and that azides are unstable under solid-phase synthesis conditions. A 97-mer single-stranded DNA containing a T7 promoter at the 3'-end (5'CAG GAC TGC TCT CAC TCT CAC GCA CCA AGA AGC TGC CAT TGA TCC CGC TGC

Generation of reactive intermediates and interception of these fleeting species under physiological conditions is a common strategy employed by Nature to build molecular complexity. However, selective formation of these species under mild conditions using classical synthetic techniques is an outstanding challenge. Here, we demonstrate the utility of biocatalysis in generating o-quinone methide intermediates with precise chemoselectivity under mild, aqueous conditions. Specifically, α-ketoglutarate-dependent non-heme iron enzymes, CitB and ClaD, are employed to selectively modify benzylic C-H bonds of o-cresol substrates. In this transformation, biocatalytic hydroxylation of a benzylic C-H bond affords a benzylic alcohol product which, under the aqueous reaction conditions, is in equilibrium with the corresponding o-quinone methide. o-Quinone methide interception by a nucleophile or a dienophile allows for one-pot conversion of benzylic C-H bonds into C-C, C-N, C-O, and C-S bonds in chemoenzymatic cascades on preparative scale. The chemoselectivity and mild nature of this platform is showcased here by the selective modification of peptides and chemoenzymatic synthesis of the chroman natural product (-)-xyloketal D.

Tris(pentafluorophenyl)gallium (3) and aluminum (7) are active coinitiators for the production of medium‐high molecular weight (MW) polymers of styrene and isobutene (IB) under aqueous reaction conditions. Strong Brønsted acids formed in situ by reaction of these coinitiators with background moisture present in the monomer droplet (5 and 8, respectively) are believed to be responsible for inducing cationic polymerization of these monomers. Of the two, 7 is the most active for IB polymerization in both aqueous media and anhydrous aliphatic solvents. These results are in contradistinction to tris(pentafluorophenyl)boron (2), which is incapable of polymerizing IB in aqueous or aliphatic media. The MWs of the polyisobutenes (PIBs) produced under aqueous conditions by either coinitiator greatly exceed those formed under similar reaction conditions by the strongly acidic chelating diborane (1,2‐C6F4[B(C6F5)2]2, 1) or diborole (1,2‐C6F4[9‐BC12F8]2, 6). Both 3 and 7 are readily synthesized from the corresponding Group 13 halide compounds in conjunction with bis(pentafluorophenyl)zinc (4). Aqueous polymerization of IB dissolved in aliphatic solvents with 3 or 7 can yield PIBs with relatively narrow polydispersities. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

This study evaluated the toxicity potential of ZnO and TiO2 nanoparticles under pre-UV-A irradiation and visible light condition on Artemia salina. The nanoparticle suspension was prepared in seawater medium and exposed under pre-UV-A (0.23mW/cm2) and visible light (0.18mW/cm2) conditions. The aggregation profiles of both nanoparticles (NPs) and dissolution of ZnO NPs under both irradiation conditions at various kinetic intervals (1, 24, 48h) were studied. The 48-h LC50 values were found to be 27.62 and 71.63mg/L for ZnO NPs and 117 and 120.9mg/L for TiO2 NPs under pre-UV-A and visible light conditions. ZnO NPs were found to be more toxic to A. salina as compared to TiO2 NPs. The enhanced toxicity was observed under pre-UV-A-irradiated ZnO NPs, signifying its phototoxicity. Accumulation of ZnO and TiO2 NPs into A. salina depends on the concentration of particles and type irradiations. Elimination of accumulated nanoparticles was also evident under both irradiation conditions. Other than ZnO NPs, the dissolved Zn2+ also had a significant effect on toxicity and accumulation in A. salina. Increased catalase (CAT) activity in A. salina indicates the generation of oxidative stress due to NP interaction. Thus, this study provides an understanding of the toxicity of photoreactive ZnO and TiO2 NPs as related to the effects of pre-UV-A and visible light irradiation.

Thiol-ene polymerizations are shown to be possible in a water-borne suspension-like photopolymerization and yield spherical particles that have diameters in the range of submicrometers to hundreds of micrometers. This is the first report of such colloidal thiol-ene polymerizations. Thiol-ene polymerization offers unique conditions not commonly associated with a water-borne polymerization including a step-growth polymerization mechanism along with photoinitiation under ambient conditions. Example polymerizations of a triene, 3,5-triallyl-1,3,5-triazine-2,4,6 (1N,3H,5H)-trione (TTT), and a tetrathiol, pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), with the photoinitiator 1-hydroxycyclohexyl phenyl ketone, surfactant sodium dodecyl sulfate (SDS), and a cosolvent (chloroform or toluene) are discussed. Various experimental parameters were examined such as surfactant concentration, homogenization energy, cosolvent species, and cosolvent amount in order to develop an understanding of the mechanism of microsphere formation. It is demonstrated that particle size is dependent on homogenization energy, with greater mechanical shear yielding smaller particles. In addition, higher concentrations of surfactant or solvent also produced smaller spherical particles. These observations lead to the conclusion that the particles are formed via a suspension-like polymerization.

Fasciolosis is a parasitic disease caused by Fasciola gigantica. The freshwater snail Lymnaea acuminata is the intermediate host of F. gigantica which cause endemic fasciolosis in the northern part of India. To investigate larvicidal activity of pure and laboratory extracted pheophorbide a (Pa) against cercaria larvae of F. gigantica, data were analyzed in different spectra of visible light, sunlight, and laboratory conditions. Photostimulation of chlorophyll derivative pheophorbide a (Pa) caused time and concentration dependent larvicidal activity against cercaria larvae of F. gigantica. Larvicidal activity of pure Pa under 650 nm and 400–650 nm (8 h LC50 0.006 mg/10 mL) was more pronounced than extracted Pa under same irradiations (650 nm LC50 0.12 mg/10 mL, 400–650 nm LC50 0.14 mg/10 mL). Lowest toxicity of pure (8 h LC50 0.14 mg/10 mL) and extracted Pa (8 h LC50 1.25 mg/10 mL) was noted under 400 nm. Pa was found to be toxic in laboratory conditions also. The results presented in this paper indicate that pheophorbide a possess potential larvicidal activity against Fasciola gigantica larvae in different wavelengths of visible light, sunlight, and laboratory conditions.

ABSTRACTAspergillus oryzae is a safe filamentous fungus widely used in the food, medicine, and feed industries, but there is currently not enough research on the light response of A. oryzae. In this study, 12 different light conditions were set and A. oryzae GDMCC 3.31 was continuously irradiated for 72 h to investigate the effect of light on mycelial growth and conidium production. Specifically, each light condition was the combination of one light wavelength (475, 520, or 630 nm) and one light intensity (20, 40, 60, or 80 μmol photon m−2 s−1). The results show that mycelium growth was inhibited significantly by green light (wavelength of 520 nm and intensities of 20 and 60 μmol photon m−2 s−1) and blue light (wavelength of 475 nm and intensity of 80 μmol photon m−2 s−1). The production of conidia was suppressed only by blue light (wavelength of 475 nm and intensities of 40, 60, and 80 μmol photon m−2 s−1), and those levels of inhibition increased when the intensity of blue light increased. When the strain was irradiated by blue light (80 μmol photon m−2 s−1), the number of conidia was 57.4% less than that of the darkness group. However, within our set range of light intensities, A. oryzae GDMCC 3.31 was insensitive to red light (wavelength of 630 nm) in terms of mycelium growth and conidium production. Moreover, interaction effects between light wavelength and intensity were found to exist in terms of colony diameter and the number of conidia. This research investigated the light response of A. oryzae, which may provide a new method to regulate mixed strains in fermented foods by light.IMPORTANCE Studies on the monochromatic light response of Aspergillus nidulans and Neurospora crassa have gone deep into the molecular mechanism. However, research methods for the light response of A. oryzae remain in the use of white light sources. In this study, we first demonstrated that A. oryzae GDMCC 3.31 was sensitive to light wavelength and intensity. We have observed that blue light inhibited its growth and sporulation and the inhibitory effect increased with intensity. This research not only adds new content to the study of the photoreaction of Aspergillus but also brings new possibilities for the use of light to regulate mixed strains and ultimately improve the flavor quality of fermented foods.

光照条件是影响昆虫生长发育及生理行为变化的重要环境因子之一.以重要的捕食性天敌异色瓢虫为研究对象,借助动物行为自动观察系统对其在不同光照强度、光周期和光波长下的交配行为及繁殖力进行了分析研究.结果显示:(1)异色瓢虫的各交配行为和繁殖能力在有光和黑暗处理间具有显著差异;(2)异色瓢虫的求偶行为不受光照强度变化的影响,而交配持续时间及交配间隔时间在高光照强度下均显著短于低光照强度.尽管异色瓢虫的累积产卵量在不同光照强度间未见显著性差异,但是其幼虫孵化率随光照强度的增强显著降低;(3)异色瓢虫在光照时间较长的条件下表现出较高的交配求偶欲望,交配持续时间及交配间隔时间随光照时间的延长而缩短,其累积产卵量和幼虫孵化率均随光照时间的延长而显著增加;(4)不同环境颜色对异色瓢虫的求偶行为没有显著影响,但是其交配持续时间及交配间隔时间随照射光波长的增加而显著降低,雌虫的累积产卵量和幼虫孵化率均在黄色(575 nm)和绿色(510 nm)条件下最高,且显著大于其它处理.结果表明异色瓢虫的交配受光照条件影响极为显著,为进一步深入研究异色瓢虫环境适应性及提升其在生物防治中大规模饲养中的扩繁效率提供了重要的理论依据.;As one of the most important environmental factors, the light condition may influence the performance of development and physiological behavior in insect. The variation of light environment could induced many negative phenomenon, such as diapause, courtship inhibition and lower food consume. The intensive research on the light influences may promote the efficiency in massive rearing and population manipulation of the natural enemy. We focused on the key predacious natural enemy coccinellid<em> Harmonia axyridi</em>s, which has been utilized as efficacious biological control agent to suppress various arthropod herbivores at present study to reveal the influences of light intensity, photoperiod and wavelength to the copulatory behavior and fertility by using an animal behavior automatic observation monitoring system. Totally 3 illuminative factors and 17 treatments, included light intensity (600 lx、900 lx、1200 lx、1500 lx、1800 lx及2100 lx), photoperiod (light: dark=0:24、6:18、12:12、18:6 and 24:0), and light wavelength (violet (395 nm), blue (480 nm), green (510 nm), yellow (75 nm), orange (610 nm) and red (685 nm)) were set as different environment conditions respectively. By reviewing the video records, the results showed that: (1) There are significant differences of each copulatory behavior and fertility between light and dark conditions of <em>H. axyridis</em>; (2) the courtship behavior was not influenced by light intensity but showed significant shorter in high intensity (in 1800 lx and 2100 lx) of copulation and interval duration that darker conditions (600 lx and 900 lx). We also did not find some significant influences by the variation of light intensity on pre-duration of mating. The offspring hatchability decreased with the increasing of light intensity although we did not find some differences of accumulation fecundity; (3) Long photoperiod and full day-light environment may enhance the courtship frequency. The ladybird couples showed significantly shorter pre-duration of mating in full-dark and short photoperiod conditions. The copulation and interval duration decreased with the prolonging of photoperiod but showed increasing in accumulated fecundity and offspring hatchability; (4) The light wavelength did not show significant influences to the courtship of male. Similarly, all couples in all colored conditions represented no different in pre-duration of mating. The mating duration and intervals duration decreased with the increasing of light wavelength. Both accumulative fecundity and larvae hatchability were showed significant highest in yellow (575 nm) and green (510 nm) conditions than rest colored treatments. The results of present study indicated the significant influences of light variation to the mating process in <em>H. axyridis</em> and it provided theoretical values for our continuous work on the environmental fitness and enhancement of plasticity adaption in biological control processes of <em>H. axyridis</em>. It indicated high illuminative intensity, long day-light photoperiod and in moderate colored (light wavelength) conditions could benefit the predacious ladybird <em>H. axyridis</em> in both massive rearing or in inoculative releasing via augmentative biological control application in greenhouse or other agroecosystem. Our study have provided the empirical witness of the value in light manipulation in insect conservation and augmentation system.

The aim of the research was to investigate the possibility of using the methods of neural image analysis and neural modeling to determine the content of dry weight of compost based on photographs taken under mixed visible and UV-A light conditions. The research lead to the conclusion that the neural image analysis may be a useful tool in determining the quantity of dry matter in the compost. Generated neural model RBF 30:30-8-1:1 characterized by RMS error 0,076378 and this networks is more effective than RBF 19:19-2:1:1 which works in visible light conditions.

The main drawback of conventional palm oil mill effluent (POME) treatment is that the process is time and space-consuming. Besides, the treatment produces highly polluted wastewater that pollutes the environment if discharged directly. Photocatalytic process has significant potential to degrade recalcitrant organic pollutants and has recently attracted tremendous attention. However, current approaches mainly focus on visible light condition, which is still an ineffective treatment for POME. In this study, POME was successfully degraded using graphitic carbon nitride (g-C3N4) photocatalyst synthesised by calcination. The prepared photocatalyst was characterised by ultraviolet-visible diffuse reflectance (UV-Vis DRS) spectroscopy and scanning electron microscopy (SEM). The SEM results revealed the morphology of g-C3N4 photocatalyst. g-C3N4 could act as a visible-light-driven (VLD) photocatalyst with the highest photocatalytic efficiency of 71% under visible light. The present work highlights the potential of g-C3N4 towards the degradation of POME under visible light and dark condition. The highly enhanced photocatalytic performance is attributed to g-C3N4, but it does not work well in round-the-clock photocatalysis. However, g-C3N4 can work as the band alignment to drive separate photogenerated charge carriers, leading to effective photocatalytic degradation. g-C3N4 photocatalyst may be considered as an ideal candidate for treating POME.