Short UV Research Articles

Application research on the development of latent fingermarks using color tunable LiZnPO4:Eu3+ phosphors

High brightness LiZnPO4:Eu3+(LZP:Eu3+)phosphors were prepared using state reaction, the emission of this phosphor at 592 nm is dominant due to there being symmetric center in the crystal structure of LiZnPO4, which corresponds to the 5D0→7F1 transition of Eu3+. The emission intensity is up to maximum when Eu3+ content is 12at. %. The excitation spectrum consists of a broad band extending 200∼280 nm and a series of sharp peaks extending 310∼500 nm, centered at 395 nm, corresponding to the charge transfer band of O2-→Eu3+ and f→f transition of Eu3+, respectively. The phosphor is excitable efficiently by 395 nm UV and short wave UV, and then was applied in the detection and imaging of lipid fingermarks on common non-porous and semi-porous substrates such as colored paper, glass, porcelain, leather, etc. All results illustrated that LZP:Eu3+ phosphor was an ideal detection powder for reduction of background interferences due to its high fluorescence brightness, offered high contrast images and applicable to the development of fingermarks on the common non-porous and semi-porous substrates

Prevention of Ocular Tenon Adhesion to Sclera by a PDMAA Polymer to Improve Results after Glaucoma Surgery.

The authors describe a process that may eventually reduce the risk of scar formation after glaucoma surgery. For this, a thin hydrogel coating is photochemically generated and linked to the sclera surface at the surgical site. This coating is generated from a photoreactive prepolymer containing anthraquinone groups, which is administered as a thin pad to the sclera surface. Short UV irradiation leads to a reaction of the photogroups with neighboring chains via C-H insertion crosslinking, thus transforming the precursor polymer into a hydrogel. Simultaneously, a reaction between the photogroups and the underlying sclera tissue occurs, so that the hydrogel patch becomes covalently linked to the tissue. The authors show that the resulting thin coating is strongly cell repellent and hinders tenon fibroblasts to form tenon tissue at the site of the coating and is suitable for inclusion into a surgical procedure.

PbSrSiO4: a new ultraviolet nonlinear optical material with a strong second harmonic generation response and moderate birefringence.

Introduction of Pb2+ cations in silicate systems generates a new compound, PbSrSiO4, which exhibits excellent properties, including a strong second harmonic generation response (∼5.8 × KDP), a short UV cut-off edge (240 nm) and moderate birefringence (0.053@1064 nm). These results suggest that PbSrSiO4 is a promising UV NLO material.

Investigation on the gemological, physical and compositional properties of some green opals from Eastern Rhodopes, Bulgaria

The physical and compositional properties of some common opals from Eastern Rhodopes, Bulgaria have been investigated through several methodologies such as optical and gemological equipments, X-Ray Powder Diffraction (XRPD), Scanning Electron Microscopy (SEM), Raman Spectroscopy and Laser Ablation Microprobe (LA-ICP-MS). The investigated opals show different colors such as light-apple and yellowish green; the diaphaneity is opaque or opaque/translucent with luster waxy/dull/greasy. They are inert to the long and short wavelength UV radiation (366–254 nm). Refractive index and specific gravity values are between 1.445–1.470 and 1.96–2.09 g/cm3, respectively. XRPD analyses show the opals are CT type and in some cases contain quartz and clay minerals (saponite). Fe and, subordinately, V appear the main chromophores that determine the green-yellowish color, while Ni is responsible for the apple and light green. Other detected trace elements are Al, Ca, K, Mg, Na, B, Zn, Rb. SEM analysis shows three types of structures already observed in the CT opals like randomly distributed nanograins and lepispheres, mammillary structure, channels structure made up by bundles of fibers. Raman spectra confirm the samples are made up by para-crystalline CT-opal, generally considered of volcanic origin, with significative content of saponite.

Rb4Li2TiOGe4O12: A Titanyl Nonlinear Optical Material with the Widest Transparency Range

AbstractPractical mid‐infrared (MIR) coherent light beams generated by frequency conversion in nonlinear optical (NLO) crystals are indispensable in time‐resolved infrared vibrational spectroscopy, remote light detection and ranging, and free‐space communications. Herein, a new titanyl germanate Rb4Li2TiOGe4O12 (RLTG) MIR NLO crystal was obtained by heavier element substitution. It features a complicated structure network composed of compressed TiO5 square pyramids and distorted GeO4 tetrahedra, separated by Rb+ and Li+ cations. More importantly, RLTG exhibits concurrently short ultraviolet (0.28 μm) and long IR (5.58 μm) transmittance cutoffs, fully covering the atmospheric transparent window of 3–5 μm. Related to the short UV cutoff, it shows a higher laser‐induced damage threshold in comparison to commercial MIR NLO crystals, about twice that of KTiOPO4 (KTP) and 50 times that of AgGaS2 (AGS).

Rb4 Li2 TiOGe4 O12 : A Titanyl Nonlinear Optical Material with the Widest Transparency Range.

Practical mid-infrared (MIR) coherent light beams generated by frequency conversion in nonlinear optical (NLO) crystals are indispensable in time-resolved infrared vibrational spectroscopy, remote light detection and ranging, and free-space communications. Herein, a new titanyl germanate Rb4 Li2 TiOGe4 O12 (RLTG) MIR NLO crystal was obtained by heavier element substitution. It features a complicated structure network composed of compressed TiO5 square pyramids and distorted GeO4 tetrahedra, separated by Rb+ and Li+ cations. More importantly, RLTG exhibits concurrently short ultraviolet (0.28 μm) and long IR (5.58 μm) transmittance cutoffs, fully covering the atmospheric transparent window of 3-5 μm. Related to the short UV cutoff, it shows a higher laser-induced damage threshold in comparison to commercial MIR NLO crystals, about twice that of KTiOPO4 (KTP) and 50 times that of AgGaS2 (AGS).

Amorphous hybrid TiO2 thin films: The role of organic ligands and UV irradiation

The development of a simple, economic and low-temperature synthesis procedure for titanium oxide thin films is an important challenge, due to their diffusion and to the limitations imposed by high temperature annealing. The knowledge on the properties of amorphous TiO2 films, as well as on the effect of their functionalization by organic compounds, is still inadequate. Here we describe a hydrolytic sol-gel procedure to prepare TiO2-based hybrid (inorganic-organic) thin films containing four different complexing agents in their structure (acetylacetone, dibenzoylmethane, citric acid and diethanolamine). The process variables were explored in order to attain stable sols and to tune the features of the amorphous films resulting by drying at 80 °C. Their structural, morphological, optical and electrical properties were studied by SEM, AFM, XRD, ellipsometry, FT-IR and UV–vis-NIR spectroscopy and resistivity measurements. The effect of the organic component, precursors concentration, deposition parameters and annealing temperature was considered. Moreover, the modifications induced by the exposure of the hybrid films to UV light were deeply investigated. A short UV treatment has a strong impact on the microstructure and wettability of the films and promotes a striking increase in their electrical conductivity.

Development of highly sensitive and low-cost DNA agarose gel electrophoresis detection systems, and evaluation of non-mutagenic and loading dye-type DNA-staining reagents.

Highly sensitive and low-cost DNA agarose gel detection systems were developed using non-mutagenic and loading dye-type DNA-staining reagents. The DNA detection system that used Midori Green Direct and Safelook Load-Green, both with an optimum excitation wavelength at ~490 nm, could detect DNA-fragments at the same sensitivity to that of the UV (312 nm)-transilluminator system combined with ethidium bromide, after it was excited by a combination of cyan LED light and a shortpass filter (510 nm). The cyan LED system can be also applied to SYBR Safe that is widely used as a non-toxic dye for post-DNA-staining. Another DNA-detection system excited by black light was also developed. Black light used in this system had a peak emission at 360 nm and caused less damage to DNA due to lower energy of UV rays with longer wavelength when compared to those of short UV rays. Moreover, hardware costs of the black light system were ~$100, less than 1/10 of the commercially available UV (365 nm) transilluminator (>$1,000). EZ-Vision and Safelook Load-White can be used as non-mutagenic and loading dye-type DNA-staining reagents in this system. The black light system had a greater detection sensitivity for DNA fragments stained by EZ-Vision and Safelook Load-White compared with the commercially available imaging system using UV (365 nm) transilluminator.

Eco-friendly green synthesis of silver nanoparticles and their potential applications as antioxidant and anticancer agents

Eco-friendly green synthesis of nanoparticles using medicinal plants gained immense importance due to its potential therapeutic uses. In the current study, silver nanoparticles (AgNPs) were synthesized using water extract of Jurinea dolomiaea leaf and root at room temperature. MTT assay was used to study anticancer potential of AgNPs against cervical cancer cell line (HeLa), breast cancer cell lines (MCF-7), and mouse embryonic fibroblast (NIH-3 T3) cell line for toxicity evaluation. The antioxidant potential was evaluated using stable DPPH radicals. In addition, the apoptotic nuclear changes prompted by AgNPs in more susceptible HeLa cells were observed using fluorescence microscope through DAPI and PI staining. Physiochemical properties of biosynthesized AgNPs were characterized using various techniques. AgNPs were formed in very short time and UV–vis spectra showed characteristic absorption peak of AgNPs. SEM and TEM showed spherical shape of AgNPs and XRD revealed their crystalline nature. EDX analysis revealed high percentage of silver in green synthesized AgNPs. FTIR analysis indicated involvement of secondary metabolites in fabrication of AgNPs. In vitro cytotoxic and antioxidant study revealed that herb and biosynthesized AgNPs exhibited significant dose-dependent and time-dependent anticancer and antioxidant potential. Furthermore, study on normal cell line and microscopic analysis of apoptosis revealed that AgNPs exhibited good safety profile as compared to cisplatin and induces significant apoptosis effect. Based on the current findings, it is strongly believe that use of J. dolomiaea offers large scale production of biocompatible AgNPs that can be used as alternative anticancer agents against cancer cell lines tested.

Unravelling Degradation Mechanisms and Atomic Structure of Organic-Inorganic Halide Perovskites by Cryo-EM

Despite rapid progress of hybrid organic-inorganic halide perovskite solar cells, using transmission electron microscopy to study their atomic structures has not been possible because of their extreme sensitivity to electron beam irradiation and environmental exposure. Here, we develop cryogenic-electron microscopy (cryo-EM) protocols to preserve an extremely sensitive perovskite, methylammonium lead iodide (MAPbI3) under various operating conditions for atomic-resolution imaging. We discover the precipitation of lead iodide nanoparticles on MAPbI3 nanowire's surface after short UV illumination and surface roughening after only 10 s exposure to air, while these effects remain undetected in conventional x-ray diffraction. We establish a definition for critical electron dose, and find this value for MAPbI3 at cryogenic condition to be 12 e-/Å2 at 1.49 Å spatial resolution. Our results highlight the importance of cryo-EM since traditional techniques cannot capture important nanoscale changes in morphology and structure that have important implications for perovskite solar cell stability and performance.

β-CsB9 O14 : A Triple-Layered Borate with Edge-Sharing BO4 Tetrahedra Exhibiting a Short Cutoff Edge and a Large Birefringence.

The first triple-layered borate with edge-sharing BO4 tetrahedra, β-CsB9 O14 was obtained under vacuum-sealed condition. It represents a new structure type and enriches the structural diversity of borates. Moreover, β-CsB9 O14 exhibits a short UV cutoff edge and a large birefringence, indicating that it could be regarded as a DUV birefringent crystal.

Assessment of Photocatalytic Hydrogen Production from Biomass or Wastewaters Depending on the Metal Co-Catalyst and Its Deposition Method on TiO2

A systematic study on the solar photocatalytic hydrogen production (photoreforming) performance of M/TiO2 (M = Au, Ag, Cu or Pt) using glucose as a model substrate, and further extended to lignocellulose hydrolysates and wastewaters, is herein presented. Three metal (M) co-catalyst loading methods were tested. Variation of the type of metal results in significantly dissimilar H2 production rates, albeit the loading method exerts an even greater effect in most cases. Deposition-precipitation (followed by hydrogenation) or photodeposition provided better results than classical impregnation (followed by calcination). Interestingly, copper as a co-catalyst performed satisfactorily as compared to Au, and slightly below Pt, thus representing a realistic inexpensive alternative to noble metals. Hydrolysates of either α-cellulose or rice husks, obtained under mild conditions (short thermal cycles at 160 °C), were rich in saccharides and thus suitable as feedstocks. Nonetheless, the presence of inhibiting byproducts hindered H2 production. A novel photocatalytic UV pre-treatment method was successful to initially remove the most recalcitrant portion of these minor products along with H2 production (17 µmol gcat−1 h−1 on Cu/TiO2). After a short UV step, simulated sunlight photoreforming was orders of magnitude more efficient than without the pre-treatment. Hydrogen production was also directly tested on two different wastewater streams, that is, a municipal influent and samples from operations in a fruit juice producing plant, with remarkable results obtained for the latter (up to 115 µmol gcat−1 h−1 using Au/TiO2).

Characterization of Pharmacognostical and Preliminary Phytochemical Features of Tubers of Dioscorea oppositifolica L.

Journal of Ayurveda Medical Sciences,2018,3,3,413-419.DOI:10.5530/jams.2018.3.21Published:April 2019Type:Original ArticleAuthors:Ravikrishna Sagri, Shrikanth Padigar, Tantrady Shridhara Bairy, and Suchitra Narayan Prabhu Author(s) affiliations:Ravikrishna Sagri *, Shrikanth Padigar, Tantrady Shridhara Bairy, Suchitra Narayan Prabhu1 Department of Dravyaguna, Sri Dharmasthala Manjunatheshwara College of Ayurveda and Hospital, 1Department of Pharmacognosy and Phytochemistry, Sri Dharmathala Manjunatheshara Centre for Research in Ayurveda and Allied Sciences, Kuthpady, Udupi 574118, India. Abstract:Introduction: Ayurveda opines that the plants which are grown in one’s own vicinity should be used for food and medicinal needs, though beneficial either as food or as medicine there are many less explored plants. Rare knowledge on folklore plants is passed on from generations to generations traditionally. One such plant is Dioscorea oppositifolia L. (Dioscoreaceae) found frequently in and around Udupi locally known as Kaadu genasu. The plant is large climber with numerous cylindrical tubers which are consumed as food as it is very nutritive and used as food during famine. On account of these utilities of this less explored plant material, a detailed pharmacognostical study including macro and microscopy was conducted. Methods: Tubers of D. oppositifolia L. was subjected to organoleptic, macro microscopic, physicochemical, HPTLC , nutritional values assessment, characterization employing standard methodology mentioned in pharmacopoeia and other herbal analysis protocols. Results: The matured tubers of D. oppositifolia L. is on an average 25 cm in length 3 to 4 cm in diameter; cylindrically elongated; outer surface is off white with lot of rootlets and cut inner surface is white and mucilaginous. TS of tuber consists of 3 to 5 layers of thin-walled cork cells, followed by cortex formed from thin-walled parenchyma having lot of starch grains; ground tissue consists of parenchyma cells consisting of cells with contents, starch grains and acicular crystals; endodermis layer which is distinct is present following cortex; groups of scattered vascular bindles, comprising of vessels with crown of phloem patches occur towards the inner regions. Preliminary phytochemical study revealed the presence of alkaloids, steroids, carbohydrates and saponins. HPTLC photo documentation showed. No spot under short UV, 4 bands under long UV and 5 bands under white light after derivatisation with vanillin sulphuric acid reagent. Conclusion: Results of this study can be utilized for identification of the drug as well as systematic document on purity standards of this extra pharmacopoeial drug. Keywords:Dioscoreaceae, Folklore, Kaadu genasu, Pharmacopoeia, StandardizationView:PDF (2.92 MB)

Photocatalytic Lithography with Atomic Layer–Deposited TiO2 Films to Tailor Biointerface Properties

AbstractIn this article, the use of thin, photocatalytically active TiO2 films deposited using atomic layer deposition (ALD) and a conventional lithography mask are explored for the fabrication of a patterned biointerface. Hereto, a pattern of self‐assembled monolayers (SAMs) with different functional groups is created using ALD TiO2 films, anatase‐rich as‐deposited, with a thickness of 20 nm and a short UV exposure time of 5 min. More specifically, azido‐containing SAMs are locally removed upon UV exposure (λ = 308 nm) and the created gaps are filled with a polyethylene glycol (PEG) SAM, hereby creating a surface with areas for the selective coupling of biomolecules via the azide groups and antifouling areas due to the presence of the PEG. To demonstrate the effectiveness of this approach, fluorescent‐labeled antibodies are immobilized on the well‐defined patterns with a resolution in the µm range.

Two Deep Ultraviolet Hydrated Borate Crystals: Centrosymmetric LiRbB5O8(OH)·H2O and Non-Centrosymmetric K2B5O8(OH)·2H2O

Two hydrated borate crystals, namely, centrosymmetric LiRbB5O8(OH)·H2O (LRB) and non-centrosymmetric K2B5O8(OH)·2H2O (K2B5), were successfully synthesized by a solvothermal technique. Although two titled compounds have the same fundamental building block B5O10(OH), the distinct linkage modes make them exhibit completely different structures. Compounds LRB and K2B5 crystallize in the nonpolar space group of P21/n and polar space group Pna21, respectively. Thermal analyses of both compounds were performed. Besides, they had short UV cutoff edge (<200 nm) according to UV–vis-NIR diffuse reflectance spectroscopy. Significantly, compound K2B5 exhibited a high laser damage threshold and moderate second harmonic generation intensity (0.84 × KDP). Furthermore, the optical properties and electronic structures of both compounds have been well studied by the density functional theory method.

NaCa5BO3(SiO4)2 with Interesting Isolated [BO3] and [SiO4] Units in Alkali- and Alkaline-Earth-Metal Borosilicates.

A new borosilicate, NaCa5BO3(SiO4)2, has been synthesized by a high-temperature solution method, which crystallizes in the centrosymmetric monoclinic space group P21/ c (No. 14), having a tangled three-dimensional (3D) network including isolated [BO3] triangles, isolated [SiO4] tetrahedra, and [CaO n] ( n = 7-9) and [NaO7] polyhedra. According to our surveys, it is the first compound containing both isolated [BO3] triangles and isolated [SiO4] tetrahedra in alkali- and alkaline-earth-metal borosilicates, which enriches the structure chemistry of borosilicates. The UV-vis-NIR diffuse reflectance spectrum shows that NaCa5BO3(SiO4)2 exhibits a wide transparent region which covers the near-IR, visible, and UV windows and displays a short UV cutoff edge at about 240 nm. Additionally, the thermal behavior (TG and DSC) and IR spectrum were also analyzed. For a deeper understanding of the relationships between the structure and properties, an analysis of theoretical calculations by density functional theory was also performed.

Responses of flavonoid profile and associated gene expression to solar blue and UV radiation in two accessions of Vicia faba L. from contrasting UV environments

Blue light and UV radiation shape a plant’s morphology and development, but accession-dependent responses under natural conditions are unclear. Here we tested the hypothesis that two faba bean (Vicia faba L.) accessions adapted to different latitudes and altitudes vary in their responses to solar blue and UV light. We measured growth, physiological traits, phenolic profiles and expression of associated genes in a factorial experiment combining two accessions (Aurora, a Swedish cultivar adapted to high latitude and low altitude; ILB938, from the Andean region of Colombia and Ecuador, adapted to low latitude and high altitude) and four filter treatments created with plastic sheets: 1. transparent as control; 2. attenuated short UV (290–350 nm); 3. attenuated UV (290–400 nm); 4. attenuated blue and UV light. In both accessions, the exclusion of blue and UV light increased plant height and leaf area, and decreased transcript abundance of ELONGATED HYPOCOTYL 5 (HY5) and TYROSINE AMINOTRANSFERASE 3 (TAT3). Blue light and short UV induced the accumulation of epidermal and whole-leaf flavonoids, mainly quercetins, and the responses in the two accessions were through different glycosides. Filter treatments did not affect kaempferol concentration, but there were more tri-glycosides in Aurora and di-glycosides in ILB938. Furthermore, fewer quercetin glycosides were identified in ILB938. The transcript abundance was consistently higher in Aurora than in ILB938 for all seven investigated genes: HY5, TAT3, CHALCONE SYNTHASE (CHS), CHALCONE ISOMERASE (CHI), DON-GLUCOSYLTRANSFERASE 1 (DOGT1), ABA INSENSITIVE 2 (ABI2), AUXIN-INDUCIBLE 2–27 (IAA5). The two largest differences in transcript abundance between the two accessions across treatments were 132-fold in CHS and 30-fold in DOGT1 which may explain the accession-dependent glycosylation patterns. Our findings suggest that agronomic selection for adaptation to high altitude may favour phenotypes with particular adaptations to the light environment, including solar UV and blue light.

Avian UV vision enhances leaf surface contrasts in forest environments

UV vision is prevalent, but we know little about its utility in common general tasks, as in resolving habitat structure. Here we visualize vegetated habitats using a multispectral camera with channels mimicking bird photoreceptor sensitivities across the UV-visible spectrum. We find that the contrast between upper and lower leaf surfaces is higher in a UV channel than in any visible channel, and that this makes leaf position and orientation stand out clearly. This was unexpected since both leaf surfaces reflect similarly small proportions (1–2%) of incident UV light. The strong UV-contrast can be explained by downwelling light being brighter than upwelling, and leaves transmitting < 0.06% of incident UV light. We also find that mirror-like specular reflections of the sky and overlying canopy, from the waxy leaf cuticle, often dwarf diffuse reflections. Specular reflections shift leaf color, such that maximum leaf-contrast is seen at short UV wavelengths under open canopies, and at long UV wavelengths under closed canopies.

Ca2GeB2O7 and Ca1.78Cd0.22GeB2O7: two acentric borogermanates with a melilite-like structure and short ultraviolet cutoff edge

Herein, two new borogermanates obtained by combining BO4 with the GeO4 tetrahedron exhibit short UV absorption edges and display second-harmonic generation signals.

Fluoroborophosphates: a family of potential deep ultraviolet NLO materials

A series of new fluoroborophosphates obtained by combining BO3F or BO2F2 with a PO4 tetrahedron exhibit short UV absorption edges and display second-harmonic generation signals.