Ultraviolet Excess Research Articles

Non-denatured yak type I collagen accelerates sunburned skin healing by stimulating and replenishing dermal collagen

Sunburn is one of the most common skin lesions caused by excessive UV exposure, and its incidence is highly correlated with the risks of skin cancer. A variety of drugs including corticosteroids and NSAIDs have been developed to treat acute sunburn, however, they have raised severe concerns such as poor healing efficacy and long recovery time. We have for the first time extracted non-denatured type I collagen from yak hide, which displays a canonical triple helical structure with melting temperature of 42.7 °C. The highly pure yak collagen type I (YCI) self-assembles to form well-ordered nanofibers with periodic d-bands. YCI is highly biocompatible, and it significantly promotes the proliferation and adhesion of HFF-1 cells. The sunburn healing effects of YCI has been investigated using acute skin injury mouse model. Histological analysis shows that 4 days’ treatment of YCI has resulted in the recovery of sunburned mice skin to a healthy state, indicated by pronounced acceleration of epithelization and collagen deposition. The collagen volume fraction as well as the hydroxyproline (Hyp) content of YCI-treated sunburned skin have been found to be greatly increased, confirming the enhanced regeneration of collagen. YCI creams and dressings have also shown superior healing capacity of sunburn by remarkably shortening the recovery time. Notably, the denatured collagen-targeted staining results indicated a large quantity of denatured collagen in sunburned mice, which became substantially reduced after the YCI treatment. FITC-labeled YCI has been further found to penetrate into the dermis of sunburned mice. The highly biocompatible and bioactive non-denatured YCI provides an improved treatment of sunburn, indicating very promising applications of YCI in cosmetics and dermatology.

The disappearances of six supernova progenitors

ABSTRACT As part of a larger completed Hubble Space Telescope (HST) Snapshot program, we observed the sites of six nearby core-collapse supernovae (SNe) at high spatial resolution: SN 2012A, SN 2013ej, SN 2016gkg, SN 2017eaw, SN 2018zd, and SN 2018aoq. These observations were all conducted at sufficiently late times in each SN’s evolution to demonstrate that the massive-star progenitor candidate identified in each case in pre-explosion imaging data had indeed vanished and was therefore most likely the actual progenitor. However, we have determined for SN 2016gkg that the progenitor candidate was most likely a blend of two objects: the progenitor, which itself has likely vanished, and another closely neighbouring star. We thus provide a revised estimate of that progenitor’s properties: a binary system with a hydrogen-stripped primary star at explosion with effective temperature ≈6300–7900 K, bolometric luminosity ≈104.65 L⊙, radius ≈118–154 R⊙, and initial mass 9.5–11 M⊙. Utilizing late-time additional archival HST data nearly contemporaneous with our Snapshots, we also show that SN 2017eaw had a luminous ultraviolet excess, which is best explained as a result of ongoing interaction of the SN shock with pre-existing circumstellar matter. We offer the caveat, particularly in the case of SN 2013ej, that obscuration from SN dust may be compromising our conclusions. This sample adds to the growing list of confirmed or likely core-collapse SN progenitors.

Association of optical, ultraviolet, and soft X-ray excess emissions in AGNs

ABSTRACT Soft X-ray emission (0.5–2.0 keV) plays a pivotal role in regulating the optical and ultraviolet (UV) emission in the active galactic nuclei (AGNs). We collected a sample of 1811 AGNs from the SDSS database and obtained various parameters of Balmer lines, optical continuum, Mg ii line & UV continuum and studied their dependencies on soft X-ray luminosity. Based on the linear regression analysis, we found that FWHM$_{\rm {Mg\,\,\small {II}}}$ ∝ FWHM$_{\text{H}\beta }^{0.554}$ suggesting that UV emission is arising from a region relatively outside the broad-line region (BLR) associated to the Hβ emission and found a strong correlation between optical and UV luminosities (L$_{\rm {Mg\,\,\small {II}}}$ ∝ $L_{\rm {H}\beta }^{0.822}$). It was noticed that the dependency of optical continuum luminosities on soft excess changes with the redshift (LX ∝ L$^{0.596}_{5100\, \mathring{\rm A}}$ for z < 0.5 and LX ∝ L$^{0.429}_{5100\, \mathring{\rm A}}$ for z > 0.5). The full width at half-maximum components of Hβ and Mg ii core components were found to be virialized and is not affected by the soft excess emission whereas the wings of Mg ii display a dependency. We estimated a relation viz. LX ∝L$^{0.520}_{3000\, \mathring{\rm A}}$ FWHM$^{0.525}_{\rm {Mg\,\,\small {II}}}$ and found to be well in agreement with a proposed physical scenario. All the derived relations were used to understand the intermodulating association of the BLR and disc in the AGNs.

In silico design, synthesis and evaluation of a less toxic octinoxate alternative with suitable photoprotection properties

Excessive UV exposure leads to several skin pathologies such as sunburns, photoaging and carcinogenesis. Currently, sunscreen use is the most important factor in protecting skin from photoinduced damage. Octinoxate is a commonly used UV filter, but its use has become controversial because it acts as an endocrine disruptor in both humans, and marine animals. Research has relied on biotechnology, structure activity relationship (SAR) studies and combinatorial chemistry to find new and less toxic UV filters. However, there are no current examples that describe the possible applications of in silico techniques for obtaining these compounds. Thus, this project sought to design an octinoxate analog that could be used as a less toxic, but equally effective, photoprotective alternative through ligand based virtual screening (LBVS). We designed 213 novel molecules based on the (E)-cinnamoyl moiety of octinoxate, but only 23 were found to be less toxic than the parent compound. Then, an artificial neural network (ANN) based model was built to predict the molar absorptivity of those 23 molecules, and the molecule that presented a similar molar absorptivity to that of octinoxate was chosen for synthesis (analog 4, 3-phenylpropyl (E)-3-(4-methoxyphenyl)acrylate).Synthesis for analog 4 resulted in a 90% yield, and its photoprotective properties, lipophilicity and cytotoxicity were then evaluated. Analog 4 absorbed UV radiation in the range of 250–340 nm, and it presented a molar absorptivity of 36,155 M − 1cm−1. Its lipophilicity was evaluated with RP-HPLC resulting in a logkw of 2.49 and its LC50 was greater than octinoxate's (67.41 nM vs. 45.67 nM). Therefore, results showed that ligand based virtual screening is an effective strategy for the development of new organic UV filters, because it guided the design of less toxic analogs and pinpointed the most likely analog to exhibit UV properties similar to those of octinoxate. In this case, analog 4 is a promising alternative to its parent compound since it proved to be more effective and less toxic.

Herbal microsponge incorporated sunscreen gel: A novel strategy

Different dermatological disorders have different effects on the lives of patients. Recently microsponge formulations have been used to treat several dermatological complications. Microsponges are basically tiny sponge like spherical particles with porous surface having valuable and attractive effect on topical delivery. The side effect of the used drug can be reduced, bioavailability can be increased, and the drug release can be modified. Microsponges can be used in different bases like gel, lotion, ointment and even in powder form. Microsponges used in sunscreen gel are now very popular. Excessive UV exposure leads to different pathological conditions like skin burns, erythema, skin carcinogenesis, etc., The microsponge sunscreen gel protects our skin from all these skin problems and most importantly, with a very less amount of side effects compared to others. Moreover, microsponges are very much cost effective, easy to handle, can deliver minimum dose of drug and enhance the stability.

Shaded places for skin cancer prevention in kindergartens and schools

HintergrundÜbermäßige UV-Strahlung der Sonne kann zu Hautkrebs führen, der häufigsten Krebsart in Deutschland. Daher wird unter anderem von der Weltgesundheitsorganisation empfohlen, ab einem UV-Index von 3 (3–5 = „mittel“) während der Mittagsstunden Schatten aufzusuchen. Diese wichtige präventive Maßnahme kann jedoch nur ergriffen werden, wenn ausreichend Schattenplätze zur Verfügung stehen. Ziel der Untersuchung ist die bundesweite Erfassung von Schattenplätzen in Kindertagesstätten und Schulen.MethodikEs wurde eine epidemiologische Querschnittstudie mit 2 Stichproben realisiert. Leitungen von Kindertagesstätten und Schulen wurden zwischen Mai und August 2020 bzw. April und Juli 2021 mittels Online-Fragebogen zur Ausstattung ihrer Bildungseinrichtung mit Beschattungsmaßnahmen befragt. Primärer Endpunkt war das Vorhandensein verschiedener struktureller Beschattungsmaßnahmen im Außenbereich der Bildungsstätten. Sekundärer Endpunkt war die Schätzung des Umfangs der beschatteten Außenfläche.ErgebnisseAus der bundesweiten Grundgesamtheit beteiligten sich 1042 Kindertagesstätten (1,9 %) und 713 Schulen (2,3 %). Im Vergleich zu Schulen verfügten Kindertagesstätten signifikant häufiger über strukturelle Sonnenschutzmaßnahmen im Außenbereich (99 % vs. 82 %; p < 0,001) und konnten eine signifikant größere Außenfläche beschatten (43 % vs. 26 %; p < 0,001). Nimmt man eine minimal benötigte beschattete Außenfläche von 1 m2 je Person an, verfügten 45 % der Schulen und 10 % der Kindertagestätten nicht über ausreichende Schattenplätze im Außenbereich (p < 0,001).SchlussfolgerungFast jede fünfte Schule Deutschlands verfügte nicht über Schattenplätze im Außenbereich. Auch vor dem Hintergrund klimatischer Veränderungen wird ein hoher Handlungsbedarf deutlich.Zusatzmaterial onlineZusätzliche Informationen sind in der Online-Version dieses Artikels (10.1007/s00103-022-03616-w) enthalten.

Monitoring accretion rate variability in the Orion Nebula Cluster with the Wendelstein Wide Field Imager

Context. The understanding of the accretion process has a central role in the understanding of star and planet formation. Aims. We aim to test how accretion variability influences previous correlation analyses of the relation between X-ray activity and accretion rates, which is important for understanding the evolution of circumstellar disks and disk photoevaporation. Methods. We monitored accreting stars in the Orion Nebula Cluster from November 24, 2014, until February 17, 2019, for 42 epochs with the Wendelstein Wide Field Imager in the Sloan Digital Sky Survey u′g′r′ filters on the 2 m Fraunhofer Telescope on Mount Wendelstein. Mass accretion rates were determined from the measured ultraviolet excess. The influence of the mass accretion rate variability on the relation between X-ray luminosities and mass accretion rates was analyzed statistically. Results. We find a typical interquartile range of ∼0.3 dex for the mass accretion rate variability on timescales from weeks to ∼2 yr. The variability has likely no significant influence on a correlation analysis of the X-ray luminosity and the mass accretion rate observed at different times when the sample size is large enough. Conclusions. The observed anticorrelation between the X-ray luminosity and the mass accretion rate predicted by models of photoevaporation-starved accretion is likely not due to a bias introduced by different observing times.

The Effects of a Magnetar Engine on the Gamma-Ray Burst-associated Supernovae: Application to Double-peaked SN 2006aj

A millisecond magnetar engine has been widely suggested to exist in gamma-ray burst (GRB) phenomena, in view of its substantial influences on the GRB afterglow emission. In this paper, we investigate the effects of the magnetar engine on the supernova (SN) emission, which is associated with long GRBs and, specifically, confront the model with the observational data of SN 2006aj/GRB 060218. SN 2006aj is featured by its remarkable double-peaked ultraviolet-optical (UV-opt) light curves. By fitting these light curves, we demonstrate that the first peak can be well accounted for by the breakout emission of the shock driven by the magnetar wind, while the primary supernova emission is also partly powered by the energy injection from the magnetar. The magnetic field strength of the magnetar is constrained to be ∼1015 G, which is in good agreement with the common results inferred from the afterglow emission of long GRBs. In more detail, it is further suggested that the UV excess in the late emission of the supernova could also be due to the leakage of the nonthermal emission of the pulsar wind nebula, if some ad hoc conditions can be satisfied. The consistency between the model and the SN 2006aj observation indicates that the magnetar engine is likely to be ubiquitous in the GRB phenomena and even further intensify their connection with the phenomena of superluminous supernovae.

Protective Effect of Ectoin on UVA/H2O2-Induced Oxidative Damage in Human Skin Fibroblast Cells

Ectoin is an amino acid derivative that can create a balance between the osmotic pressure of cells and can protect enzymes, DNA proteins, and nucleic acids under extreme conditions. Ectoin has also been reported to slow skin aging. However, there are few reports on the protective effect of Ectoin on oxidative damage, especially on the regulation of PI3K/AKT-pathway-related genes at the mRNA level. UVA-induced oxidative stress injury and H2O2-induced oxidative stress injury are two common oxidative stress injury models. Skin fibroblasts produce a large number of ROS following excessive UV radiation or oxidative stimulation by H2O2, which further inhibits cell proliferation and causes cell apoptosis. In this study, UVA- and H2O2-induced oxidation models of human skin fibroblasts were established separately to investigate the protective effect of Ectoin. Further studies on the mechanisms involved, for example, the expression levels of genes associated with the PI3K/AKT signaling pathway and levels of antioxidant enzymes in cells, were determined. We found that Ectoin upregulated genes associated with the PI3K/AKT signaling pathway, including COL1A1, COL1A2, FN1, IGF2, NR4A1, and PIK3R1, but decreased intracellular ROS levels and malondialdehyde (MDA), while increasing the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). In conclusion, our results indicate that Ectoin exerts protective properties by the upregulated genes COL1A1, COL1A2, FN1, IGF2, NR4A1, and PIK3R1 and upregulating antioxidative enzyme levels.

Cancer Prevention Prioritized at AACR Annual Meeting and a New Working Group.

Scientific advances in the late 19th century set the stage for progress in understanding and treating cancer, a disease that was previously considered almost hopeless. One hundred years later, cancer prevention is becoming an increasingly important focus for oncology research. New tools and ideas bring to the field some extremely promising molecular, organizational, social, and political approaches, which were a focus of the American Association for Cancer Research 2022 Annual Meeting and of the newly launched AACR Cancer Prevention Working Group (CPWG). We are moving toward precision prevention, better tools for early detection and for risk assessment, the use of a Precancer Atlas, unveiling of new biomarkers. Besides improving lifestyle, by avoiding risk factors such as tobacco use, excessive UV exposure, infectious agents, as well as poor dietary habits, lack of exercise, overweight, and obesity, many other factors can impact cancer risk, which is a warning to consider a multifaceted molecular but also social approach. Gender, ethnicity, geographic, and economic lines are associated with disparities in prevention, which we want to overcome. Here we summarize some challenges and priorities in cancer prevention emerging from the work of AACR and CPWG.

Progress in health effects and measurement standards of ultraviolet radiation in the workplace

Ultraviolet radiation affects human health. On the one hand, moderate amounts of UV radiation can promote human health and have the effect of promoting vitamin D production; but on the other hand, excessive UV radiation can also cause adverse effects on human skin and eyes, such as causing skin photoaging, skin cancer, electrophthalmia and cataracts to occur. Therefore, the measurement of ultraviolet radiation is extremely important. This paper mainly reviews the health effects of ultraviolet radiation and the progress of measurement standards in the workplace, and puts forward suggestions on the revision of the existing standards from five aspects including use new measuring instruments and methods, improve the existing measuring instruments, specify the number of measurements, expand the scope of application of the standards and consider the influence of the sun on the measurement of artificial ultraviolet radiation, so as to provide reference for the revision of new standards.

Design and implementation of an Internet-Based cancer risk assessment tool: Use over 10 years.

Prevention and early intervention can improve survival and quality of life across all cancers. Patient understanding of risk factors and associated actionable lifestyle changes and screening programs is not well understood by clinicians METHODS: An Internet-based tool, Reduce My Risk, was created in 2009 and made available on oncolink.org. Users voluntarily completed a survey regarding demographics and cancer risk factors, and received information about their cancer risk RESULTS: Twenty eight thousand and one surveys were completed from 2009 to 2019. Median age was 26 years (18-101); 60% were females, 87% lived in North America, and 37% had at least a bachelor's degree. Users reported on behavioral/ modifiable risk factors: 13% were current smokers, 52% were current consumers of alcohol, and 8% of those had ≥14 drinks/week. Body mass index (BMI) was ≥30 in 19%; 74% of all surveys reported dietary risks and 36% reported infrequent exercise. Excess UV exposure was reported by 19%. Among women, 36% reported performing breast self-examinations monthly, and 50% reported receiving clinician breast examinations at least once every 3 years. Sixty seven percent of men 55-75 years reported screening prostate specific antigen testing, with 50% receiving annual digital rectal examinations. Nonmodifiable risk factors included family cancer history (64%), genetic syndrome (3%), and cancer-predisposing health conditions (26%) CONCLUSIONS: Ninety-seven percent of users reported modifiable risk factors, and 60% reported ≥4 of these risk factors. Understanding detailed characteristics of a large number of respondents has the potential to improve educational interventions to reduce cancer risk through behavioral modification and cancer screening across the general public.

Optical and Near-infrared Excesses are Correlated in T Tauri Stars

Abstract Accretion is one of the defining characteristics of classical T Tauri stars, fueled by the presence of a circumstellar disk comprised of dust and gas. Accretion produces a UV and optical excess, while re-radiated emission at the inner edge of the dust component of the disk produces a near-infrared (NIR) excess. The interplay between stars and their disks helps regulate protoplanetary disk evolution and dispersal, which is key to a full understanding of planet formation. To investigate the relations between NIR excess and optical excess in both single and binary stars, we used an archival sample of spectroscopically characterized members of the Taurus star-forming region (τ ∼ 1–2 Myr) with measured luminosities, spectral types, and optical veiling. We combined the archival sample with the Two Micron All Sky Survey and Wide-field Infrared Survey Explorer NIR photometry and high-resolution imaging surveys. We found that NIR and optical excesses are correlated in multiple NIR photometric bands, suggesting that they are closely related, likely because more massive disks have higher inner dust disk walls and are also associated with higher accretion rates. We also found that multiplicity has no impact on accretion or inner disk properties in a sample with a wide range of separations, but the sample was too small to specifically investigate close binaries, where the effects of multiplicity on disk properties should be most significant.

YY Hya and its interstellar environment

Context. During a search for previously unknown Galactic emission nebulae, we discovered a faint 36′ diameter Hα emission nebula centered around the periodic variable YY Hya. Although this star has been classified as an RR-Lyr variable, such a classification is inconsistent with a Gaia distance of ≃450 pc. The GALEX image data also show YY Hya as having a strong UV excess, suggesting the existence of a hot and compact binary companion. Aims. We aim to clarify the nature of YY Hya and its nebula. Methods. In addition to our discovery image data, we obtained a 2.°5 × 2.°5 image mosaic of the whole region with CHILESCOPE facilities and time-series spectroscopy at MDM observatory. Also, we used data from various space missions to derive an exact orbital period and a spectral energy distribution. Results. We find that YY Hya is a compact binary system containing a K dwarf star that is strongly irradiated by a hot white dwarf companion. The spectral characteristics of the emission lines that are visible only during the maximum light of the perfectly sinusoidal optical light curve show signatures resembling those of members of the BE UMa variable family. These are post-common-envelope pre-cataclysmic variables. However, the companion star here is more massive than that found in other group members and, thus, the progenitor of the white dwarf must have been a star between 3 and 4 M⊙. The nebula appears to be an ejected common-envelope shell with a mass on the order of one M⊙ and an age of 500 000 yr. This makes it the biggest such shell known thus far. The alignment of neighboring nebulosities some 45′ to the northeast and southwest of YY Hya suggests that the system has had strong bipolar outflows. We also briefly speculate that it might be related to the 1065 BP “guest-star” reported in ancient Chinese records.

ROS-responsive hollow mesoporous silica nanoparticles loaded with Glabridin for anti-pigmentation properties

Excessive UV irradiation induces photoaging and overproduction of melanin, which darkens the skin and affects appearance. To efficiently enhance transdermal delivery and anti-pigmentation, a novel ROS-responsive transdermal nanocarrier for the whitening agent Glabridin by integrating the cell-penetrating peptide polyarginine R8 and borate ester bond into hollow mesoporous silica nanoparticles (HMSNs) has been designed, in which beta-cyclodextrin (β-CD) was grafted onto the surfaces of HMSNs via boronic ester bond to avoid premature release of Glabridin, and R8 conjugated adamantane (Ada) was anchored on HMSN-β-CD via host-gust interaction to enhance the drug delivery efficiency. The ROS-responsive HMSN-β-CD/Ada-R8 nanocarrier was characterized by TEM, FTIR, TGA, Zeta potential, N2 adsorption, stability, and other parameters. The nanocarrier rapidly penetrated through the epidermis into the keratinocytes and melanocytes and released Glabridin in a controlled ROS-responsive manner. Glabridin released from nanocarriers reversed UV-induced oxidative damage and phototoxicity and reduced hyperpigmentation. Taken together, our study provides a guidance for the design and fabrication of functional transdermal drug nanocarriers for cosmetic applications.

A Bright Ultraviolet Excess in the Transitional 02es-like Type Ia Supernova 2019yvq

Abstract We present photometric and spectroscopic observations of the nearby Type Ia SN 2019yvq, from its discovery ∼1 day after explosion to ∼100 days after its peak brightness. This SN exhibits several unusual features, most notably an extremely bright UV excess seen within ∼5 days of its explosion. As seen in Swift UV data, this early excess outshines its “peak” brightness, making this object more extreme than other supernovae (SNe) with early UV/blue excesses (e.g., iPTF14atg and SN 2017cbv). In addition, it was underluminous M B = −18.4, relatively quickly declining (Δm 15(B) = 1.37), and shows red colors past its early blue bump. Unusual (although not unprecedented) spectral features include extremely broad-lined and high-velocity Si absorption. Despite obvious differences in peak spectra, we classify SN 2019yvq as a transitional member of the 02es-like subclass due to its similarities in several respects (e.g., color, peak luminosity, peak Ti, and nebular [Ca ii]). We model this data set with a variety of published models, including SN ejecta–companion shock interaction and sub-Chandrasekhar-mass white dwarf (WD) double-detonation models. Radio constraints from the VLA place an upper limit of (4.5–20) × 10−8 M ⊙ yr−1 on the mass-loss rate from a symbiotic progenitor, which does not exclude a red giant or main-sequence companion. Ultimately, we find that no one model can accurately replicate all aspects of the data set, and further we find that the ubiquity of early excesses in 02es-like SNe Ia requires a progenitor system that is capable of producing isotropic UV flux, ruling out some models for this class of objects.

291 In vitro efficacy of a sunscreen (50+) and octatrienoic acid 0.1% in actinic keratosis and UVs damages

Actinic keratosis (AK) is a form of dysplastic epidermal lesions resulting from chronic and excessive UV exposure with a certain risk to become cancerous. The use of sunscreens to prevent photodamages is advocated by the current guidelines on AK treatment. To be efficient a photoprotection has to involve UV filters but also secondary factors such as antioxidants and anti-inflammatory agents able to counteract the photochemical and genetic cascade triggered by UVs. In the present work we used an in vitro model of human skin (Phenion® Ft) in order to assess the photoprotective potential of a sunscreen containing inorganic sun-filters (50+ SPF) and 0.1% octatrienoic acid (KERA’+) after UVA (10J/cm2) and UVB (25mJ/cm2) by mean of evaluation of the number of sunburn cells and apoptotic keratinocytes.

Protective effects of sunscreen (50+) and octatrienoic acid 0.1% in actinic keratosis and UV damages

Actinic keratosis is a form of dysplastic epidermal lesion resulting from chronic and excessive UV exposure with a certain risk of becoming cancerous. Current guidelines advocated the use of sunscreens...

UOCS – VI. UVIT/AstroSat detection of low-mass white dwarf companions to four more blue stragglers in M67

ABSTRACTBlue straggler stars (BSSs) in M67 have attracted attention from observations and theory to unravel their formation mechanisms. In the series of Ultra Violet Imaging Telescope (UVIT on AstroSat) study of Open clusters (UOCS), here we report the detection of hot companions to 4 more BSSs (WOCS 2013, WOCS 3013, WOCS 4006, and WOCS 5005), using Far-UV photometry obtained in two epochs from UVIT. We characterize the hot companions to be low to extremely low mass (LM/ELM) white dwarfs (WDs) with Teff ∼ 13–23 kK, R/R⊙ ∼ 0.035–0.051, M/M⊙ ∼ 0.19–0.3, and age ∼25–300 Myr using WD models. Two BSSs (WOCS 1025 and WOCS 3005) showed UV excess, and may have a hot companion, but we are unable to confirm/characterize. 13 BSSs are detected by UVIT in the two epochs of data, of the total 14 present in M67. We have performed detailed analysis on 10 BSSs, including our previous studies. Five BSSs are found to have LM/ELM WD companions, suggesting Case-B mass-transfers (MT) to be prevalent in M67 (with a lower limit of 37.5 per cent, 5/14), along with other mechanisms. Three BS+WD systems have orbital parameters outside the limit for stable MT as per the models. We speculate the following three possibilities – their orbits are altered due to cluster dynamics, some may be in triple systems with LM/ELM WDs in an unknown closer orbit, or a modified MT mechanism may be required to enable their formation.

FORMULATION OF SOLAR CREAM EXTRACT ETHANOL GANGGANG GREEN (Ulva lactuca L.) AND IN VITRO TEST OF SPF VALUE (SUN PROTECTING FACTOR)

&lt;p&gt;Excessive ultraviolet radiation or UV rays will make the epidermal tissue in the skin unable to resist the harmful effects. Sunscreen is a cosmetic ingredient that functions as a physical or chemical function as a barrier to the penetration of UV rays into the skin. Plants that can function as sunscreens because they have phenolic compounds, one of which is green algae (&lt;em&gt;Ulva lactuca&lt;/em&gt; L).&lt;/p&gt;&lt;p&gt;This type of research is an experimental study using UV-Vis spectrophotometry to determine the ability of sun cream to inhibit UV radiation to the skin. The purpose of this study was to formulate sunscreen cream from ethanol extract of green algae (&lt;em&gt;Ulva lactuca&lt;/em&gt; L.) and measure the best SPF (&lt;em&gt;Sun Protecting Factor&lt;/em&gt;) value of various concentrations of green algae (Ulva lactuca L.) ethanol extract sunscreen cream.&lt;/p&gt;&lt;p&gt;The results of the study the SPF value of formula 1 (cream base) was 1.5077, which means formula 1 has no activity as sunscreen, formula 2 (3% green algae extract) with formula 2 (3% extract extract) with an SPF value of 7,311 which is classified as in the extra protection category, formula 3 (4% extract concentration) has an SPF value of 13,427 which is included in the maximum protection category and formula 4 with an SPF value of 19,282 which belongs to the ultra protection category. The cream formulation with the highest SPF value was formula 4. The higher the extract concentration, the higher the SPF value.&lt;/p&gt;