Violet Light Research Articles

Hydraulic fracturing as unconventional production potential for the organic-rich carbonate reservoir rocks in the Abu El Gharadig Field, north western Desert (Egypt): Evidence from combined organic geochemical, petrophysical and bulk kinetics modeling results

This paper systematically analyzes the organic geochemical, petrophysical, and petrographical properties combined with bulk kinetics modeling of the Abu Roash (F) organic-rich carbonate rocks in the Abu El Gharadig Field. The Abu Roash (F) carbonate-rich samples exhibit high organic content with total organic matter (TOC) values up to 3.04 wt%, and mainly Type II kerogen, with a slight gradient to Type II/III and III kerogens, reaching good to very good oil generation potential. This finding of hydrogen-rich kerogen and oil generation potential was also demonstrated by the abundance of fluorescent alginite, amorphous organic matter (AOM), and bituminite organic matter (OM) as established via ultra violet (UV) light microscopy. The maturity indicators demonstrate that most of the examined Abu Roash (F) carbonate-rich samples from the studied wells, with a deep burial depth of more than 3000 m, are thermally mature, thus defining an early mature to moderate-mature stage. The kinetic models suggest that the Abu Roash (F) carbonate-rich rocks in the deepest burial depth, with calculated vitrinite reflectance (%VRo) values in the range of 0.72–0.83 %, have reached kerogen transformation ratio (TR) in the range of 10–55 %, indicating a high probability of oil production. This finding is confirmed by the presence of the oil crossover in these rocks with an oil saturation index (OSI) of more than 100 mg HC/ g rock. The Abu Roash (F) organic-rich carbonates are intractable rocks as implied by low porosities (up to 2.33 %) and poor permeability in the range of 0.0017–0.0039 mD. The pores in these rocks have a wide range in size, including interparticle, fracture, and organic matter (OM) pores, as recognized in the thin section and scanning electron microscopy (SEM). The development of these pore types and their quality is mainly controlled by high mineralogical brittleness (i.e., carbonates) together with the high OM inputs. Based on the above characteristics, the Abu Roash (F) carbonate-rich rocks in the Abu El Gharadig Field are a candidate for unconventional tight oil reservoir potential, which typically require a form of hydraulic fracturing for possible oil production at deeper burial depths.

Utilization from ultraviolet to infrared light for CO2 reduction with P4O10/TiO2 photocatalyst

This study aims to extend the light spectrum which could be absorbed by TiO2 to infrared ray light (IR) by loading P4O10 in order to promote the CO2 reduction performance of TiO2 photocatalyst. Three ranges of light with P4O10/TiO2 film are studied, which are ultra violet light (UV) + visible light (VIS) + IR, VIS + IR, and IR only. This study also investigates the impact of molar ratio of CO2/H2O or CO2/NH3 on the CO2 reduction characteristics of P4O10/TiO2 film. The largest CO2 reduction performance in case of CO2/H2O and CO2/NH3 is obtained at CO2:H2O = 1:1 and CO2:NH3 = 3:2 respectively, irrespective of light illumination condition. With IR light illumination only, the largest molar quantity of CO per unit weight of photocatalyst for P4P10/TiO2 film in case of CO2/H2O and CO2/NH3 is 2.36 mmol/g and 33.4 mmol/g, respectively.

Visible light photochemical synthesis of ultrasmall palladium/copper bimetallic particles at room temperature and its catalytic application in degradation of p-NP

Pt-based metals are very effective catalysts widely adopted in many fields. But the high cost prevents its further industrial application. One of the effective ways to solve the problem is to replace platinum with relatively cheap palladium and its alloy with copper. However, producing Pd/Cu bimetallic catalysts efficiently and economically with controllable particle size and uniform distribution is still challenging, especially when trying to reduce the consumption of precious metals. In this paper, ultrasmall palladium/copper (Pd/Cu) bimetallic catalysts with even dispersion were prepared on multi-walled carbon nanotubes (MWCNTs) by adding polyethylene glycol 400 (PEG 400) as a reducing agent and stabilizer under visible light irradiation at room temperature. The catalytic performance was studied in the catalysis of p-nitrophenol (p-NP) reduction. Of all the bimetallic catalysts produced in different conditions, the best one was obtained under the reaction condition of pH = 7 and violet light irradiation (wavelength 380–435 nm). The average particle size of 0.85 nm, and the apparent rate constant in the catalysis is 1.47 min−1. This research probes the role of visible light as a key kinetic controlling method in the formation of ultrasmall particles (UPs). It proves the effectiveness of using visible light irradiation as an effective and more “green chemistry” approach to get precious metal UPs as catalysts beyond the traditional ultraviolet or laser photochemistry methods.

Exploring the private universe of Henri Matisse in The Red Studio

The exhibition Matisse: The Red Studio allowed for an in-depth study of The Red Studio (1911) and six of the works featured in the painting by Henri Matisse (1869–1954) of his studio in Issy-les-Moulineaux near Paris. The grouping includes three paintings from the collection of the Statens Museum for Kunst (Le Luxe II, 1907, Nude with White Scarf, c. 1909, and Bathers, c. 1909), one painting from the collection of The Metropolitan Museum of Art (Young Sailor II, 1906), a painting from a private collection (Cyclamen, c. 1911), and a glazed and hand-painted earthenware plate from the collection of the Museum of Modern Art (Untitled (Female Nude), 1907). The six paintings were investigated using technical (X-radiography, ultraviolet-induced fluorescence, infrared reflectography) and chemical imaging (MA-XRF) and, in some cases, spectroscopic techniques (FORS, SEM–EDS, Raman, SERS, and μ-FTIR), to better elucidate Matisse’s materials and working techniques for this selection of paintings; the plate was also analyzed using MA-XRF. New findings revealed the full extent to which Matisse had completed The Red Studio before applying its hallmark color, referred to as Venetian red in his correspondence, over the original palette of blue, pink, and ochre that dominated the composition. Particular attention was given to identifying the wide range of pigment choices made by Matisse in the execution of the works from 1906 and 1911 that are depicted in The Red Studio. These pigments include lead white, zinc white, bone black, earth reds, madder lake, carmine lake, vermilion, cadmium yellow, yellow ochre, aureolin (cobalt) yellow, orpiment, viridian green, chromium-oxide green, cobalt blue, ultramarine blue, Prussian blue, cobalt violet (deep and light), and other cobalt violets, as well as possibly manganese violet and eosin red lake. The results of these analyses allowed for a direct comparison between the original works and their depictions and revealed that Matisse, unsurprisingly given his strong association with color, often translated the pigment choices faithfully between the actual works and their depictions in The Red Studio.

Short-Term Exposure to Violet Light Emitted from Eyeglass Frames in Myopic Children: A Randomized Pilot Clinical Trial.

Violet light (VL), 360–400 nm wavelength, is contained in the sunlight and is an effective element for myopia suppression. This study is to investigate the safety and efficacy of novel eyeglasses that emit VL from the frames. This is a double-masked, randomized, pilot clinical trial conducted in a clinic in Japan. Forty-three children with myopia were enrolled. Participants were randomly assigned to two groups, wearing VL-emitting eyeglass frames (VLf) that emitted VL of 310 μW/cm2 (VLf group, n = 22) or pseudo-placebo eyeglass frames with a minimal emission of VL (<10 μW/cm2) (control group, n = 21). The exposure time was 3 h per day. The primary outcomes were visual acuity, tear film break-up time, corneal endothelial cell density, and the slit-lamp/fundus examinations. The secondary outcome was the 6-month changes in the axial lengths and cycloplegic refractions. Forty-one (95%) participants were included; twenty-one in the VLf group and twenty in the control group. No significant differences were seen in any safety evaluation. Significant changes were seen in axial elongation, choroidal thickness, and cycloplegic refractions in the subgroup analysis of 8- to 10-year-old children (p < 0.05), but otherwise no significant differences were seen. The VLf showed short-term safety and effectiveness against myopia progression.

(Invited) Advancing Human-Centric Lighting

The concept of human-centric lighting stems from the evolution of sunlight’s intensity and color temperature throughout the course of a day. This natural progression of bright cold-white light during the middle of the day to a softer warm-white light in the evening stimulates intrinsic photosensitive retinal ganglion cells that control our circadian rhythm. The blue-hue of daylight activates these cells to produce dopamine and cortisol while suppressing melatonin, the sleep hormone, to keep humans awake and alert. The current generation of energy-efficient LED lights reproduce daylight by converting a blue-emitting LED into a broad-spectrum white light using inorganic phosphors. Unfortunately, the resulting intense blue-hue generated by cheap LED bulbs and the underlying blue light from even the most expensive bulbs have been shown to cause macular degeneration, cataract formation, mood disorders, and circadian disruption, resulting in insomnia and fatigue. This talk will investigate the production of a ‘human-centric’ light that minimizes blue light by using a violet LED chip and inorganic phosphors. We report a new phosphor, Na2MgPO4F:Eu2+, which can be readily excited by violet light to produce a bright blue emission. This material possesses all the necessary requirements for LED lighting, including a high quantum yield, thermally robust emission, and impressive chemical stability. Incorporating this material into a prototype device demonstrates our ability produce a warm-white light with a higher color rendering index than a commercially purchased LED light bulb while significantly reducing the blue component.

Radiofrequency thermal balloon angioplasty of vulnerable atherosclerotic plaque accompanied by delta-aminolevulinic acid photodynamic therapy and catheter-based samarium-153 brachytherapy

Abstract Background The balloon angioplasty methods that are currently in use, cause to inflammation and subsequent neoatherosclerosis. Purpose The aim of this study was to evaluate the effect of combined photodynamic therapy and brachytherapy on inflammation and intimal hyperplasia reduction after radiofrequency thermal balloon angioplasty of carotid artery in an animal model of thin fibrous cap atheromatous plaque, wherein a high resolution diagnostic ultrasound is adjuncted with angioplasty and combination therapy system, with a goal of increased safety. Methods Briefly, New Zealand white rabbits were submitted to carotid artery vulnerable atherosclerotic plaque by primary intravascular balloon injury followed by a 1.5% cholesterol-rich diet for eight weeks. Histopathology results showed the formation of advanced atherosclerosis with a foam cell-rich atheromatous plaque, resulted in severe stenosis (&amp;gt;70%) in all of the rabbits' arteries. Then treatment group underwent B-mode ultrasound-guided radiofrequency thermal balloon angioplasty followed by catheter-based samarium-153 brachytherapy (153Sm, 18 Gy, β particles) and photosensitizer delta-aminolevulinic acid (delta-ALA)-mediated fiber optic catheter-based polarized light-emitting diodes (LEDs) violet light (λ±Δλ = 405±5 nm, E/A = 120 J/cm2) photodynamic therapy. Results Results from ultrasonography and histopathology showed a significant reduction in the mean value for macrophages, lymphocytes, mast cells, foam cells and hyperplastic vascular smooth muscle cells density after angioplasty in the treatment group compared with the other groups (p&amp;lt;0.05). Conclusion Apoptotic effect of brachytherapy in combination with cytotoxic and anti-inflammatory effect of delta-ALA photodynamic therapy on immune cells and hyperplastic vascular smooth muscle cells, can cause to reduce the neoatherosclerosis in the intimal layer. These findings provide the basis for developing of combined brachytherapy and photodynamic therapy for a successful clinical application in the inhibition of neoatherosclerosis after radiofrequency thermal balloon angioplasty. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Mehrad Research Lab

Double-Layered Strategy for Broadband Photomultiplication-Type Organic Photodetectors and Achieving Narrowband Response in Violet, Red, and Near-Infrared Light.

Broadband photomultiplication-type organic photodetectors (PM-OPDs) were prepared with PMBBDT:PY3Se-2V (1:1, wt/wt) as the absorbing layer (AL) and PC71BM:P3HT (100:5, wt/wt) as the photomultiplication layer (PML) on the basis of the sandwich structure. The incident photons from ultraviolet light to the near-infrared region can be harvested by AL. The rather less P3HT in PML can produce plenty of isolated hole traps with P3HT surrounded by PC71BM; the electron tunneling injection induced by trapped holes near the Ag electrode can lead to the photomultiplication (PM) phenomenon. The performance of PM-OPDs can be effectively improved by optimizing the AL thickness. The optimal PM-OPDs exhibit a broad spectral response from 300 to 1050 nm as well as an external quantum efficiency (EQE) of 5800% at 340 nm at 10 V bias, along with a specific detectivity (D*) of 3.78 × 1013 Jones. The spectral response of PM-OPDs is controlled by the trapped-hole distribution near the Ag electrode, primarily originating from the photogenerated holes in AL. To further optimize the spectral response of PM-OPDs, the optical filter layer (OFL) was used to manipulate light field distribution in AL. The violet, red, and near-infrared-light PM-OPDs were developed by employing different OFLs.

New Possibilities on the Application of Violet Light in Dentistry Combining Aesthetics and Microbiological Control: Report of Two Clinical Cases

Dental bleaching performed in a dental office is considered among the bleaching techniques one of the most safety avoiding damages to the mucous membranes and to the gastrointestinal tract of the patient. The application of violet light appears as an innovative reality in dental bleaching with effective results. The aim of this study was to show the new possibilities of violet LED light (405 nm, 165 mW/cm2) with liquid peroxide solution used during the dental bleaching in two clinical cases. Dental bleaching was done using a violet LED light source and simultaneous irrigation used hydrogen peroxide liquid on the dental arches with the aim of also promoting oral decontamination in the patient. Based on the results, it was possible to show that violet light has real applicability in tooth whitening and potential to be used in oral decontamination. In addition, the violet light accelerates the whitening process allowing excellent results and minimizing the aggressiveness of this procedure to the patients. Thus, violet light is a new tool for tooth whitening with the advantage of combining the control and prevention of diseases initiated by microorganisms in the oral cavity.

Highly Active Rutile TiO2 for Photocatalysis under Violet Light Irradiation at 405 nm

Anatase TiO2 is a widely investigated photocatalyst; however, it can only work under ultraviolet (UV) light with wavelengths less than 390 nm (band gap 3.2 eV). Rutile TiO2 can absorb visible light at wavelengths less than 410 nm (band gap 3.0 eV); however, its photocatalytic activity is not high. Herein, we activated rutile TiO2, which was prepared from Evonik TiO2 P 25 through calcination at 800 °C using hydrogen reduction treatment at 700 °C. The photocatalytic activity of the hydrogen-treated TiO2 was as high as P 25 under UV irradiation at 380 nm, which was significantly higher than P 25 under violet light irradiation at 405 nm for the oxidative decomposition of acetic acid in water. Electron spin resonance studies indicate that charge separation is enhanced in reduced TiO2, and their oxygen reduction pathways differ between anatase and rutile. The formation of H2O2 was observed on rutile TiO2; however, it was consumed during photocatalysis to accelerate acetic acid decomposition.

Effect of azobenzene composition ratio on the degree of photosoftening: Experimental and molecular dynamics simulation studies

Azobenzene-incorporated liquid crystalline polymer (azo-LCP), which undergo property change and deformation upon Ultra violet and visible light stimulation, are promising materials in various fields. This study investigated the effect of azobenzene concentration on photosoftening based on the photoisomerization of an azo-LCP. The experimental results confirmed that as the azobenzene concentration increased, the order parameter decreased and mechanical properties deteriorated. Photoisomerization and photosoftening was also conducted on an azo-LCP unit cell constructed by molecular dynamics simulation. The simulation results showed that changes in the order parameter, length contraction and elastic modulus due to the photosoftening, in alignment with the experimental results.

Investigation of the light output of 3D-printed plastic scintillators for dosimetry applications

Three-dimensional (3D) printing, specifically digital light processing (DLP) technique, can be used to manufacture plastic scintillators of any shape. The purpose of this study was to determine the light output of DLP 3D-printed scintillators for dosimetry applications. Two types of plastic scintillators with dimensions 10 mm × 10 mm × 10 mm were fabricated using DLP 3D-printing at Hanyang University, South Korea. The light output of these DLP 3D-printed samples was measured and compared to that of a commercial plastic scintillator of the same dimensions, RP-408, produced by casting. The 3D-printed scintillators emitting violet and blue light had a lower relative light output by 49% and 43%, respectively, compared to the RP-408 reference scintillator. We also investigated three types of scintillator surface finishing methods: the original surface made by the 3D printer, a sanded surface, and a polished surface. Furthermore, three wrapping configurations were tested: bare scintillator, diffuse-type polytetrafluoroethylene tape, and specular-type enhanced specular reflector foil. Both reflector types, diffuse and specular, reflected blue light with comparable efficiency. Additionally, emission and transmission spectra of the samples were measured. Emission maxima were located at 430 nm for RP-408, and 438 and 475 nm for two 3D-printed samples. Transmittance at the wavelength of maximum emission was equal to 89% for RP-408, and 73% and 66% for the two DLP-printed samples. Although the light output of the 3D-printed scintillators was about 50% lower than that of the commercial plastic scintillator, due to characteristics of 3D-printed plastic scintillators, i.e. fast, low-cost production, and easy customization of the printed shape, they are promising as an active part of dosimeters for use in high intensity gamma radiation fields produced by medical linear accelerators with acceptable signal-to-noise ratio level.

Light-Driven Hydrodefluorination of Electron-Rich Aryl Fluorides by an Anionic Rhodium-Gallium Photoredox Catalyst.

An anionic Rh-Ga complex catalyzed the hydrodefluorination of challenging C-F bonds in electron-rich aryl fluorides and trifluoromethylarenes when irradiated with violet light in the presence of H2 , a stoichiometric alkoxide base, and a crown-ether additive. Based on theoretical calculations, the lowest unoccupied molecular orbital (LUMO), which is delocalized across both the Rh and Ga atoms, becomes singly occupied upon excitation, thereby poising the Rh-Ga complex for photoinduced single-electron transfer (SET). Stoichiometric and control reactions support that the C-F activation is mediated by the excited anionic Rh-Ga complex. After SET, the proposed neutral Rh0 intermediate was detected by EPR spectroscopy, which matched the spectrum of an independently synthesized sample. Deuterium-labeling studies corroborate the generation of aryl radicals during catalysis and their subsequent hydrogen-atom abstraction from the THF solvent to generate the hydrodefluorinated arene products. Altogether, the combined experimental and theoretical data support an unconventional bimetallic excitation that achieves the activation of strong C-F bonds and uses H2 and base as the terminal reductant.

Light‐Driven Hydrodefluorination of Electron‐Rich Aryl Fluorides by an Anionic Rhodium‐Gallium Photoredox Catalyst

AbstractAn anionic Rh−Ga complex catalyzed the hydrodefluorination of challenging C−F bonds in electron‐rich aryl fluorides and trifluoromethylarenes when irradiated with violet light in the presence of H2, a stoichiometric alkoxide base, and a crown‐ether additive. Based on theoretical calculations, the lowest unoccupied molecular orbital (LUMO), which is delocalized across both the Rh and Ga atoms, becomes singly occupied upon excitation, thereby poising the Rh−Ga complex for photoinduced single‐electron transfer (SET). Stoichiometric and control reactions support that the C−F activation is mediated by the excited anionic Rh−Ga complex. After SET, the proposed neutral Rh0 intermediate was detected by EPR spectroscopy, which matched the spectrum of an independently synthesized sample. Deuterium‐labeling studies corroborate the generation of aryl radicals during catalysis and their subsequent hydrogen‐atom abstraction from the THF solvent to generate the hydrodefluorinated arene products. Altogether, the combined experimental and theoretical data support an unconventional bimetallic excitation that achieves the activation of strong C−F bonds and uses H2 and base as the terminal reductant.

Brownification of freshwater promotes nitrogen-cycling microorganism growth following terrestrial material increase and ultraviolet radiation reduction

Brownification is an increasingly concerning phenomenon faced by aquatic ecosystems in the changing environments, and the microbiome plays an irreplaceable role in material circulation and food web construction. Insight into the influence of brownification on microbial communities is crucial from an ecological standpoint. In this study, we simulated brownification using a the mesocosm system and explored the relationship between the characteristics of microbial communities and brownification using excitation-emission matrix (EEM) fluorescence spectroscopy and ultraviolet (UV) spectroscopy combined with high-throughput amplicon sequencing techniques. The results showed that brownification reduced the richness of the microbial community and selectively promoted the growth of nitrogen-cycling microorganisms, including hgcI_clade, Microbacteriaceae, and Limnohabitans. Brownification affected microbial communities by altering the carbon source composition and underwater spectrum intensity; UV, blue, violet, and cyan light were significantly (p < 0.05) correlated with microbial community richness, and random forest analysis revealed that UV, C1 (microbial humic-like), and C3 (terrestrial humic-like) were the major factors significantly influencing microbiome variation. We found that brownification affected microorganisms in shallow lakes, especially nitrogen cycling microorganisms, and propose that controlling terrestrial material export is an effective strategy for managing freshwater brownification.

ARGET ATRP of Methyl Acrylate and Methyl Methacrylate with Diazocine-Derived Initiators

Diazocine-functionalized initiators for atom transfer radical polymerization (ATRP) were synthesized and tested for their efficiency in controlled radical polymerizations of methyl acrylate and methacrylate under reaction conditions for activators regenerated by electron transfer (ARGET). The α-bromoisobutyl condensates of anilide and benzyloxycarbonate required high amounts of reducing agents and catalysts for the initiation. On the other hand, violet light irradiation during ATRP caused severe retardation or termination during initiation of the anilide compound, in contrast to the previously reported photoinduced initiation under otherwise very similar conditions. The final linear elastomers obtained from optimized polymerization kinetics responded to light irradiation of 405 and 525 nm wavelengths by Z/E photoisomerization of diazocine in both solution and in the solid state. The E → Z thermal relaxation rate was highly influenced by electronic effects on the diazocine ring, the solvent, and the polymer matrix in the solid state. Our polymers find potential use as photonic materials in ultraviolet light sensors and optical waveguides.

3D-Printed Fluorescence Hyperspectral Lidar for Monitoring Tagged Insects

Insects play crucial roles in ecosystems, and how they disperse within their habitat has significant implications for our daily life. Examples include foraging ranges for pollinators, as well as the spread of disease vectors and pests. Despite technological advances with radio tags, isotopes, and genetic sequencing, insect dispersal and migration range remain challenging to study. The gold standard method of mark-recapture is tedious and inefficient. This paper demonstrates the construction of a compact, inexpensive hyperspectral fluorescence lidar. The system is based on off-the-shelf components and 3D printing. After evaluating the performance of the instrument in the laboratory, we demonstrate its efficient range-resolved fluorescence spectra in situ. We present daytime remote ranging and fluorescent identification of auto-powder-tagged honey bees. We also showcase range-, temporally- and spectrally-resolved free-flying mosquitoes, which were tagged through feeding on fluorescent-dyed sugar water. We conclude that violet light can efficiently excite administered sugar meals imbibed by flying insects. Our field experiences provide realistic expectations of signal-to-noise levels, which can be used in future studies. The technique is generally applicable and can efficiently monitor several tagged insect groups in parallel for comparative ecological analysis. This technique opens up a range of ecological experiments, which were previously unfeasible.

Safety-by-design using forward and inverse multi-target machine learning

The economic and social future of nanotechnology depends on our ability and manufacture nanomaterials that avoid potential toxicity, by identifying them before they are made, used and released into the environment. Safety-by-design is a framework for including these issues at an early stage of the development process, but balancing multiple nanoparticle properties and selection criteria remains challenging. Based on a synthetic data set of over 19,000 possible sunscreen product specifications, we have used multi-target machine learning to predict the corresponding size, shape, concentration and polytype of titania nanoparticle additives. The study considers the optical properties responsible for the sun protection factor and product transparency, including the extinction coefficients for ultra violet and visible light, and the potential for toxicity due to the generation of reactive oxygen species from the photocatalytically active facets of both anatase and rutile nanoparticles, as a function of the size and shape. We predict a number of conventional forward structure/property and property/product relationships, but show that a direct structure/product relationship provides superior performance when predicting multiple properties or product specifications simultaneously. These models are then inverted, re-optimized and re-trained to provide focused, high performing inverse design models that do not require additional optimization, and are capable of identifying nanoparticle configurations outside of the training set. The ability to directly predict suitable nanoparticle structures that conform to prerequisite sun protection, transparently and potential toxicity thresholds represents a new approach to safety-by-design that can be applied to other products and materials where multiple design criteria must be met at the same time.

Effect of samarium oxide nanoparticles on virulence factors and motility of multi-drug resistant Pseudomonas aeruginosa.

Biofilm formation and quorum sensing (QS) dependent virulence factors are considered the major causes of the emergence of drug resistance, therapeutic failure and development of Pseudomonas aeruginosa infections. This study aimed to investigate the effects of samarium oxide nanoparticles (Sm2O3NPs) on biofilm, virulence factors, and motility of multidrug-resistant P. aeruginosa. Sm2O3NPs were synthesized using curcumin and characterized by Transmission Electron Microscopy, X-ray diffractometer, Field Emission Scanning Electron Microscopy, and Energy-dispersive X-ray spectroscopy. Minimum inhibitory concentration (MIC) was determined using broth microdilution method. The antibiofilm potential of Sm2O3NPs was also evaluated by crystal violet staining and light microscopy examination. Then, the effect of sub-MICs concentrations of Sm2O3NPs on the proteolytic and hemolytic activities of P. aeruginosa was investigated. Finally, the effect of Sm2O3NPs on various types of motility including swarming, swimming, and twitching was studied. Our results showed that Sm2O3NPs significantly inhibited biofilm formation of P. aeruginosa by 49-61%. Additionally, sub-MICs concentrations of Sm2O3NPs effectively decreased virulence factors including pyocyanin (33-55%), protease (24-45%), and hemolytic activity (22-41%). Moreover, swarming, swimming, and twitching motility remarkably was reduced after exposure to the NPs. The findings of this work showed that Sm2O3NPs have a high potential in inhibiting QS-dependent virulence of P. aeruginosa, which could be considered for antibacterial chemotherapy after further characterization.

Crystal Engineering and Photomagnetic Studies of CN-Bridged Coordination Polymers Based on Octacyanidometallates(IV) and [Ni(cyclam)]2.

A series of new CN-bridged coordination networks of different dimensionality and topology was obtained through the modification of reaction conditions between [Ni(cyclam)]2+ (cyclam = 1,4,8,11-tetraazacyclotetradecane) and [W(CN)8]4–. The factors determining the reaction pathway are temperature and addition of the LiCl electrolyte. The products include three negatively charged frameworks incorporating Li+ guests: the 1D Li2[Ni(cyclam)][W(CN)8]·6H2O (1) straight chain, the 1D Li2[Ni(cyclam)][W(CN)8]·2H2O (2) zigzag chain, and the 2D Li2[Ni(cyclam)]3[W(CN)8]2·24H2O (3) honeycomb-like network, as well as the 3D two-fold interpenetrating [Ni(cyclam)]5[Ni(CN)4][W(CN)8]2·11H2O (4) network and the 1D [Ni(cyclam)][Ni(CN)4]·2H2O (5) chain, which result from partial decomposition of the starting complexes. Together with the previously characterized 3D [Ni(cyclam)]2[W(CN)8]·16H2O (6) network, they constitute the largest family of CN-bridged coordination polymers obtained from the same pair of building blocks. All compounds exhibit paramagnetic behavior because of the separation of paramagnetic nickel(II) centers through the diamagnetic polycyanidometallates. However, the presence of the photomagnetically active octacyanidotungstate(IV) ions allowed observation of the magnetic superexchange after the violet light excitation (405 nm) for compound 3, which constitutes the first example of the photomagnetic effect in a NiII–[WIV(CN)8] system. The photomagnetic investigations for fully hydrated and dehydrated sample of 3, as well as for the isostructural octacyanidomolybdate(IV)-based network are discussed.