29 research outputs found

    Wavepacket insights into the photoprotection mechanism of the UV filter methyl anthranilate

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    Meradimate is a broad-spectrum ultraviolet absorber used as a chemical filter in commercial sunscreens. Herein, we explore the ultrafast photodynamics occurring in methyl anthranilate (precursor to Meradimate) immediately after photoexcitation with ultraviolet radiation to understand the mechanisms underpinning Meradimate photoprotection. Using time-resolved photoelectron spectroscopy, signal from the first singlet excited state of methyl anthranilate shows an oscillatory behavior, i.e. quantum beats. Our studies reveal a dependence of the observed beating frequencies on photoexcitation wavelength and photoelectron kinetic energy, unveiling the different Franck-Condon overlaps between the vibrational levels of the ground electronic, first electronic excited, and ground cationic states of methyl anthranilate. By evaluating the behavior of these beats with increasing photon energy, we find evidence for intramolecular vibrational energy redistribution on the first electronic excited state. Such energy redistribution hinders efficient relaxation of the electronic excited state, making methyl anthranilate a poor choice for an efficient, efficacious sunscreen chemical filter

    Derivation of Vertical Profiles of Droplet Size in Cumulus Clouds from Passive Remote Sensing Observations by the Research Scanning Polarimeter

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    The Research Scanning Polarimeter (RSP) is an airborne along-track scanner measuring the polarized and total reflectance in 9 spectral channels. Its uniquely high angular resolution allows for characterization of liquid water cloud droplet sizes using the rainbow structure observed in the polarized reflectance over the scattering angle range from 135 to 165 degrees. Such an angular resolution coupled with high frequency of the RSP measurements also allows for geometric constraint of the cumulus cloud's 2D cross section between a number of tangent lines of view, thus, providing estimates of the macroscopic parameters of the cloud, such as its geometric shape, dimensions, and height above the ground

    Development and characterization of biocomposite films using banana pseudostem, cassava starch and poly(vinyl alcohol): A sustainable packaging alternative

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    To meet the need for sustainable packaging, we introduce a novel biocomposite film consisting of banana pseudostem, cassava starch, and poly(vinyl alcohol). We aimed to evaluate the optimal biocomposite film composition, which is characteristic for packaging materials. Using the solvent casting method, we produced biocomposite films with varying proportions (10–40 % w/w) of the lignocellulosic component from both Sour and Ash Plantain banana pseudostems. The resulting biocomposite films were characterized for mechanical, chemical, thermal, water absorption, gas permeability, and morphological properties. At the 25 % lignocellulosic level, a notable drop (P < 0.05) in tensile strength and elongation was observed, while water absorption increased, and gas permeability decreased. Fourier Transform Infrared Spectroscopy analysis revealed insights into the structural attributes of lignocellulosic composites. Thermogravimetric analysis indicated an onset temperature of 120 °C for thermal degradation, confirming the biocomposite's thermal stability. A fundamental discovery emerged with the optimal composition at a 30 % pseudostem powder inclusion, offering an exceptional balance of tensile strength, elongation at break, water absorption, and gas permeability. This breakthrough holds significant implications for eco-friendly biocomposite films, particularly in food packaging. Future work may be undertaken to further explore banana pseudostems' potential in creating biocomposite films with advanced functionalities and their broader applications, including characterizations

    TOTAL POLYPHENOL CONTENT AND ANTIOXIDANT AND CYTOTOXIC ACTIVITIES OF THE SRI LANKAN ENDEMIC PLANT GENUS SCHUMACHERIA

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    Objective: Schumacheriais a genus endemic to Sri Lanka distributed in lowland rain forests and mountain rain forests. The total polyphenol content and antioxidant and cytotoxic activities of hexane, dichloromethane and methanol extracts of stem-bark, root-bark, leaves and flowers of the three representative plant speciesS. castaneifolia, S. alnifolia and S. angustifolia belonging to the endemic genus Schumacheriaare reported. Methods: Antioxidant activity was determined using the DPPH (1,1-diphenyl-2-picrylhydrazine) radical scavenging assay. The total polyphenol content, expressed as the gallic acid equivalent, was determined using theFolin-Ciocaltue method and the cytotoxic activity was determined using the brine shrimp (Artemiasalina) assay.Results: The methanol extract of S. castaneifolia flowers (IC50 = 6.8 ± 0.1 ppm)and the methanol extracts of S. alnifolia stem-bark (IC50 =7.1 ± 0.4 ppm) and leaves (IC50 =8.3 ± 0.3 ppm) showed antioxidant activity higher than that of α-tocopherol(IC50 = 10.9 ± 4.3 ppm). The methanol extracts of S. alnifolia stem-bark (69.3 ± 6.9 mg g-1) and leaf (57.7 ± 0.0 mg g-1) extracts showed the highest polyphenol content closely followed by the methanol extracts of S. castaneifolia flowers (71.2 ± 0.6 mg g-1). The highest cytotoxic activity was exhibited by the methanol extract of S. castaneifolia flowers (LC50 = 1.3 ± 0.7 ppm), and all the other extracts showed comparatively less cytotoxic activity.Conclusion: S. castaneifolia and S. alnifolia exhibit potent bioactivitiesvalidating the ethnomedical claims where the former has been used for oral aphthous.Â

    The Frequency and Spectrum of Chromosomal Translocations in a Cohort of Sri Lankans

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    Translocations are the most common type of structural chromosomal abnormalities. Unbalanced translocations are usually found in children who present with congenital abnormalities, developmental delay, or intellectual disability. Balanced translocations are usually found in adults who frequently present with reproductive failure; either subfertility, or recurrent pregnancy loss. Herein, we report the spectrum and frequency of translocations in a Sri Lankan cohort. A database of patients undergoing cytogenetic testing was maintained prospectively from January 2007 to December 2016 and analyzed, retrospectively. A total of 15,864 individuals were tested. Among them, 277 (1.7%) had translocations. There were 142 (51.3%) unbalanced translocations and 135 (48.7%) balanced translocations. Majority (160; 57.8%) were Robertsonian translocations. There were 145 (52.3%) children and adolescents aged less than 18 years with translocations, and 142 (97.9%) were unbalanced translocations. Majority [138 (95.2%)] were referred due to congenital abnormalities, developmental delay, or intellectual disability, and 91 were children with translocation Down syndrome. All adults aged 18 years or above (132) had balanced translocations. Subfertility and recurrent pregnancy loss [84 (63.6%)] and offspring(s) with congenital abnormalities [48 (36.4%)] were the most common indications in this group. Majority (68.2%) in this group were females with reciprocal translocations (55.3%). Chromosomes 21, 14, and 13 were the most commonly involved with rob(14q21q) [72 (26%)], rob(21q21q) [30 (13.7%)], and rob(13q14q) [34 (12.3%)] accounting for 52% of the translocations. Chromosomes 1, 8, 11, and 18 were most commonly involved in reciprocal translocations. The observed high frequency of chromosomal translocations in our cohort highlights the importance of undertaking cytogenetic evaluation and providing appropriate genetic counseling for individuals with the phenotypes associated with these translocations

    Double Flutter in an Aeroelastic System

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    Selected hazards and ways of their minimization in the steel industry

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    W artykule przedstawiono wybrane zagrożenia występujące w przemyśle hutniczym. Szczególną uwagę zwrócono na zagrożenia związane z obecnością substancji niebezpiecznych, w tym pyłów i gazów procesowych, gazów palnych, jak również niepożądanych produktów ich spalania: CO2, CO czy NOx. Niewłaściwe postępowanie z nimi może być przyczyną niekontrolowanego uwalniania się ww. gazów, a w konsekwencji pożaru lub wybuchu. Odpowiednio szybka identyfikacja zagrożenia może zminimalizować, a nawet wyeliminować ryzyko jego wystąpienia. Dlatego też w artykule, jako istotny element bezpieczeństwa każdego zakładu przemysłowego, wskazano odpowiedni system detekcji gazów. Opisany system może nie tylko zmniejszyć ryzyko związane z wystąpieniem poważnej awarii, ale przede wszystkim ograniczyć skutki bezpośredniego zagrożenia zatruciem lub utratą życia ludzi znajdujących się w pobliżu miejsca uwalniania się gazów.The article presents the selected hazards that may exist in the steel industry. Particular attention was paid to the risks associated with the hazardous substances, including particular matters and process gases, combustible gases such as coal gas or natural gas, as well as the unwanted products of combustion: CO2, CO and NOx. Improper handling of them can cause uncontrolled release, and consequently can lead to fire or explosion. Accordingly fast hazard identification can minimize or even eliminate the risk of its occurrence. Therefore, in the article a suitable gas detection system, as an important element of the safety of each industrial plant was pointed out. The system described in the article can not only reduce the risk of suffering a major accident, but firstly to minimize the effects of direct danger of poisoning or loss of life of people in the vicinity of the gases release
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