Dark Lines Research Articles

Study of Illuminating the Future Exploring the Possibilities of Glow in the Dark Roads

As part of its $245 million road safety program, the Australian government is installing some innovative new techniques to keep not just drivers safe, but cyclists and pedestrians too. The country plans to install photo-luminescent road markings that glow in the dark. The lines on the road will appear normal in the daytime, but in the night, they will glow just like the stars. In the part of Smart Highways with Glowing Lines the road glow in the dark lines is installed, called Glowing Lines. These lines collect energy during the day and give light in the evening. Here the landscape becomes an experience of light and information. As a result, this increases visibility and safety.

Electrostatic discharge induced degradation of optical-electrical properties and defect evolution of GaAs-based oxide-confined VCSELs.

GaAs-based oxide-confined vertical-cavity surface-emitting lasers (VCSELs) exhibit relatively low resistance against reliability-related damage. In order to gain a deeper understanding of the degradation and failure mechanism in oxide-confined VCSELs caused by electrostatic discharge (ESD)-induced defect proliferation, we investigated the effects of ESD stress on the degradation of optical-electrical characteristics and the evolution of defects in VCSELs under human body model test condition. The degradation threshold values for forward and reverse ESD pulse amplitudes were estimated to be 200 V and -50 V, respectively. Notably, VCSELs demonstrated greater sensitivity to reverse bias ESD compared to forward bias ESD. Analysis of optical emission and microstructure provided evidence that the device failure is attributed to an increase in ESD current density, leading to the multiplication of dark line defects (DLDs) originating from the edge of the device's oxide aperture. The formation of defects occurred suddenly in discrete events within small regions, rather than progressing gradually and uniformly. These defects propagated and led to damage across the entire active region. We believe that our results would be meaningful for improving the reliability of VCSEL in the future.

Spontaneous emission spectrum from a V-type artificial atom in a strong-coupling regime: Dark lines and line narrowing

Spontaneous emission spectrum from a V-type artificial atom in a strong-coupling regime: Dark lines and line narrowing

Neuroprotective Activity of 5-ethoxy-2-ethylthiobenzimidazole (Etomerzol) and 2-ethylthiobenzimidazole (Bemitil) in a Model of Middle Cerebral Artery Occlusion

Introduction. Cerebrovascular diseases (CVD) are one of the most pressing medical and social problems due to the high rate of mortality and disability. Stroke is the leading cause of CVD. About 15 million strokes are registered annually in the world according to the World Federation of Neurological Societies. It should be noted that CVD of ischemic origin has a tendency to rejuvenation and growth. Traditionally, in clinical practice, antihypoxic, antioxidant agents, as well as drugs with neuroprotective and neurorehabilitation effects are used to treat CVD. In connection with the increase in the incidence of CVD, there is an urgent need to search for promising neuroprotectors.Aim. To study the neuroprotective activity of 5-ethoxy-2-ethylthiobenzimidazole (etomerzol) and 2-ethylthiobenzimidazole (bemityl) in a model of middle cerebral artery occlusion.Materials and methods. Occlusion of the middle cerebral artery (ОMCA) was used as a model. The object of the study was inbred male rats of the Dark Agouti line, randomized into five groups: a group of intact animals and four groups with OSMA: a control group, a group with the introduction of 5-ethoxy-2-ethylthiobenzimidazole (etomerzole, 25 mg/kg), a group with the introduction 2-ethylthiobenzimidazole (bemityl, 25 mg/kg) and a group with the reference drug dimethyl fumarate (DMF, 100 mg/kg). On the 1st, 3rd, and 7th days after the operation, the "Limb Stimulation" (SC) test was performed. On the 7th day, the tests "Open field" (OP) and "Elevated plus maze" (EPM) were performed. Euthanasia was performed on the 7th day in an induction chamber (Bioscape GmbH, CO2 box for euthanasia, Germany).Results and discussion. The study showed a pronounced pharmacological effect of etomerzole in a model of acute ischemic stroke. The introduction of bemitil, etomerzol and DMF significantly reduced the neurological deficit 24 hours after OSMA and improved the psycho-functional state on the 7th day. Thus, in the etomerzol group on the first day after surgery, the neurological deficit was reduced by 1.9 times (p < 0.05), and by 3 and 2.0 times (p < 0.05) compared with the control group. While bemityl and DMF reduced the index by 1.3 (p < 0.05) and 1.4 times (p < 0.05) on the 3rd day and by 1.5 times (p < 0.05) on the 7th day. In the OP test in the etomerzol group, an increase in HDA by 2.7 times (p < 0.05) was observed compared with the control. The rate of peering into minks in the etomersol and bemitil groups was higher than in the control group by 2.6 (p < 0.05) and 3.4 times (p < 0.05), respectively. Search and research activity was increased in the same groups by 2.0 (p < 0.05) and 2.2 times (p < 0.05) compared to control animals. In the PCL test, the etomerzol and DMF groups showed an increase in the number of uprights in the sleeves compared to the control group by 2.7 (p < 0.05) and 3.8 times (p < 0.05), respectively. In the etomerzol and bemityl groups, there was an increase in the number of overhangs by 3.4 (p < 0.05) and 6.2 times (p < 0.05).Conclusion. The data obtained during the study of the activity of benzimidazoles after ischemic stroke indicate a significant increase in the motor activity of animals in the OP tests, which may indicate a psychostimulating and potential nootropic effect of etomerzole and bemitil, and an increase in the number of racks and hangings in the PCL test can be regarded as manifestation of anxiolytic activity. In our study, the severity of the pharmacological effects of DMF was inferior to benzimidazoles. However, a significant decrease in neurological deficit in the SC test and an increase in the number of uprights in the sleeves in the PCL may indicate the presence of anxiolytic activity in the drug. The results obtained underline the importance of conducting additional studies to evaluate the effectiveness of DMF in OSMA.

Day and Night, Light and Darkness in the Bacchae of Euripides

In my paper, I am following the theme of light and darkness in the Bacchae of Euripides. Light and darkness is one of many threads of meaning in the Bacchae. It runs alongside the overall interpretation of the play. Light and darkness are present in the characterisations of Dionysus and Pentheus. More than that, the characterisations through light and darkness change in accordance with the story of the play. A close reading of Bacchae along the lines of light and darkness can, thus, help to determine which evaluations of Pentheus and Dionysus are inscribed in the play. The drama of light and darkness suggests an interpretation of the sparagmos as an expiating sacrifice and the restoration of harmony at the end of the play.

Principle Operation of a Line Follower Robot

A rudimentary autonomously guided robot called a "Line Follower Robot" (LFR) follows a line written on the ground to either find a white line on a dark surface or a dark line on a white surface. Working on the LFR is quite interesting. We will discover how to construct a black line follower robot in this study utilizing an Arduino Uno and a few readily available parts.

Formation of the hydrogen line 21-cm in Dark Ages and Cosmic Dawn: dependences on cosmology and first light

ABSTRACT We analyse the formation of the redshifted hyperfine structure line 21-cm of hydrogen atom in the Dark Ages, Cosmic Dawn, and Reionization epochs. The evolution of the global differential brightness temperature in this line was computed to study its dependence on the values of cosmological parameters and physical conditions in the intergalactic medium. Variations of the depth of the Dark Ages absorption line at z ∼ 80 with variations of the cosmological parameters Ωb, Ωcdm, ΩΛ, ΩK, and H0 are studied. The standard model with post-Planck parameters predicts a value of the differential brightness temperature in the centre of the absorption line ∼30–50 mK. The profile of this line can be quite another in the non-standard cosmological models, which include the annihilating or decaying dark matter, a primordial stochastic magnetic field, etc. It can be shallower or be an emission bump instead of an absorption trough. It is also shown that the position and depth of the Cosmic Dawn absorption line formed at 10 < z < 30, due to the Wouthuysen–Field effect, is mainly defined by the spectral energy distribution of the first sources of light. If reionization occurs at zri = 7 ± 1, then the differential brightness temperature in the centre of this line is ∼80 mK. During the reionization, the emission with an amplitude of ∼20 mK is possible. It is also shown that the temperature, density, and degree of ionization of the baryonic component are decisive in calculating the intensity of the 21-cm absorption/emission line from these epochs.

Semen Quality of Captive Fishing Cats (Prionailurus viverrinus) Obtained by Electroejaculation

Fishing cat (Prionailurus viverrinus) is categorized in a group of small cats. The cat has brownish grey fur with dark brown spots and lines running across the length of body. It is wildlife conserved (IUCN) and protected as wildlife animal in Thailand. It is also in the CITES Appendix II. The aim of this study was to study semen quality of this cat by electroejaculation. Five male fishing cats aging approximately 13 years old and body weighed between 9-16 kg were employed in this study. Anesthetic by dexmedetomidine (0.02 mg/kg) and ketamine (4 mg/kg)) was used before semen collection. Stimulation patterns for electrical stimuli using 0.5-5 volts by autonomous program were applied into the rectum of each fishing cat using the rectal probe (r=1.27 cm). Semen was successfully collected from sixteen out of twenty attempts. Semen volume and sperm motility were much variable. Average semen volume was 43.13 µl (range between 5-200 µl). Average pH was 5.81 (range from 5-7). Average sperm motility was 28.25 % (range from 1-90 %). Average sperm concentration was 207.44 million/ml (range from 12-860 million/ml). The semen collection method developed in this study proved to be a useful technique for frozen semen preservation and planning of artificial insemination in order to propagate and conserve the threatened and endangered fishing cat species in the future.

Sustainable Synthesis and Characterizationof Corncob‐Derived Graphene Oxide

AbstractRecently, though graphene oxide (GO) has shown promising applications in many fields, there have not been many studies focusing on exploiting the source of synthetic precursors of GO. Herein, GO was synthesized from the cellulose of corncob by corncob alkalization, bleaching cellulose, pyrolysis, and improved Hummer's method. It was found that pyrolysis plays an important role in the graphitization of cellulose precursors with the catalyst Fe(NO3)3 to form Gi‐Fe(NO3)3. The GO material synthesized from Gi‐Fe(NO3)3 was characterized by advanced analytical methods. The X‐ray diffraction pattern of Gi‐Fe(NO3)3 shows the formation of a diffraction peak at the crystal plane (002), which is characteristic of the graphite material. The synthesized GO underwent a series of changes in material structure and morphology, which are confirmed via transmission electron microscopy images showing a plate‐like structure with folds represented by the dark line. This study demonstrates a sustainable approach that directly utilizes abundant biomass resources for the synthesis of GO material.

Large-area WS2 Deposited on Sapphire and Its In-Plane Raman and PL Spectral Distributions

Large-area and high-quality WS2 monolayer has been fabricated on the Al2O3 substrate. Three typical WS2 configurations were adopted to examine the in-plane spectral properties. For the triangle WS2 monolayer, the PL light region exhibits a large peak wavelength and could be deduced to be the relaxation of the compressed strain of the WS2 monolayer and the low defect density. For triangle WS2 monolayer with multilayer WS2 on center, combining the peak intensity and position results of PL and Raman spectra, the line traces near the side of the center triangle can be demonstrated to be the defects or dislocations due to the exist of the central multilayer WS2. For large-area WS2 monolayer with crystal domain, PL area integrated mapping shows a uniform light region across the whole surface, except the existing dark crystal domain boundary. The dark line traces could be attributed to compressed strain in the WS2 monolayer due to the formation of the WS2/Al2O3 hybrid structure. The in-plane PL and Raman spectra and mapping exhibited in this work reveal the distribution of stress and defects in this system and further clarify the effects of stress and defects on the optoelectronic properties of WS2 monolayer on Al2O3.

Principle Operation of a Line Follower Robot

A rudimentary autonomously guided robot called a "Line Follower Robot" (LFR) follows a line written on the ground to either find a white line on a dark surface or a dark line on a white surface. Working on the LFR is quite interesting. We will discover how to construct a black line follower robot in this study utilizing an Arduino Uno and a few readily available parts.

Reading Teeth

While artifacts made of ivory fill the shelves and storage rooms of museum collections across the world, ever more stringent legal measures restricting or banning the ivory trade have turned these objects into troublesome treasures. Ivory is a biological material derived from the tusks and teeth of several extant and extinct animals. The physical and aesthetic properties of elephantine ivory in relation to its use and symbolic significance shaped the material cultures of classed whiteness at the turn of the twentieth century. Ivory from elephant tusks displays a characteristic macroscopic motif known as the Schreger pattern, which is often used by conservators and forensic researchers as an identifying characteristic. First described by German odontologist Bernhard Schreger in 1800, this pattern of crossing dark and bright lines is attributed to an optical phenomenon of light refraction. By proposing a refractive reading of ivory, this article explores the role of animal-derived materials in the construction of human identities. This method of analysis allows the properties of ivory—luster, brilliance, whiteness, and toughness—to be seen as agentive material properties that historically co-produced human racial and classed ideals. Analyzing nineteenth- and early twentieth-century sources in dental anatomy, ivory commerce, and technical microscopy permits an unraveling of this animal material’s ties to specific colonial regimes of trade and resource extraction, and its technical role in precursors to materials science. This paper is part of a special issue entitled “Making Animal Materials in Time,” edited by Laurence Douny and Lisa Onaga.

Search for dark matter lines at the Galactic Center with 14 years of Fermi data

Dark matter (DM) in the Milky Way halo may annihilate or decay to photons, producing monochromatic gamma rays. We search for DM-induced spectral lines using 14 years of data from the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope ($\textit{Fermi}$-LAT) between $10\,\mathrm{GeV}$ and $2\,\mathrm{TeV}$ in the inner Milky Way leveraging both the spatial and spectral morphology of an expected signal. We present new constraints as strong as $\langle \sigma v \rangle \lesssim 6\times 10^{-30}\, \mathrm{cm}^3/\mathrm{s}$ for the two-to-two annihilations and $\tau \gtrsim 10^{30}\,\mathrm{s}$ for one-to-two decays, representing leading sensitivity between $10\,\mathrm{GeV}$ and $\sim$$500\,\mathrm{GeV}$. We consider the implications of our line-constraints on the Galactic Center Excess (GCE), which is a previously-observed excess of continuum $\sim$GeV gamma-rays that may be explained by DM annihilation. The Higgs portal and neutralino-like DM scenarios, which have been extensively discussed as possible origins of the GCE, are constrained by our work because of the lack of observed one-loop decays to two photons. More generally, we interpret our null results in a variety of annihilating and decaying DM models, such as neutralinos, gravitinos, and glueballs, showing that in many cases the line search is more powerful than the continuum, despite the continuum annihilation being at tree level.

Synthesis of infrared Stokes spectra in an evolving solar chromospheric jet

ABSTRACT Chromospheric jets are plausible agents of energy and mass transport in the solar chromosphere, although their driving mechanisms have not yet been elucidated. Magnetic field measurements are key for distinguishing the driving mechanisms of chromospheric jets. We performed a full Stokes synthesis in the infrared range with a realistic radiative magnetohydrodynamics simulation that generated a chromospheric jet to predict spectropolarimetric observations from the Sunrise Chromospheric Infrared spectro-Polarimeter (SCIP) onboard the SUNRISE III balloon telescope. The jet was launched by the collision between the transition region and an upflow driven by the ascending motion of the twisted magnetic field at the envelope of the flux tube. This motion is consistent with upwardly propagating non-linear Alfvénic waves. The upflow could be detected as continuous Doppler signals in the Ca ii 849.8 nm line at the envelope where the dark line core intensity and strong linear polarization coexist. The axis of the flux tube was bright in both Fe i 846.8 nm and Ca ii 849.8 nm lines with downflowing plasma inside it. The structure, time evolution, and Stokes signals predicted in our study will improve the physical interpretation of future spectropolarimetric observations with SUNRISE III/SCIP.

Postmortem Tanning: An Unusual Postmortem Event.

A variety of changes, many predictable and others more aberrant, occur during the postmortem interval. A number of these changes are largely influenced by various environmental conditions. We describe 3 cases of an unusual postmortem change associated with prolonged sunlight exposure in both frozen and nonfrozen individuals. In each case, very well-delineated, dark tanning lines were present where clothing or another object blocked sunlight. This change appears distinct from mummification and scant literature references that describe a tanned skin transformation in cases associated with burials in high salt-containing bogs. Collectively, the cases highlight a novel postmortem phenomenon known as postmortem tanning. The potential mechanism(s) of this change is discussed within the context of known observations. Increased recognition and knowledge of postmortem tanning are exceedingly important in assessing how this change may assist in postmortem scene analysis.

Divide and focus: generating novel focal polarization modalities by symmetry-based phase tailoring in one dimension.

Symmetry-based tailoring of photonic systems recently heralded the advent of novel concepts, such as photonic topological insulators and bound states in the continuum. In optical microscopy systems, similar tailoring was shown to result in tighter focusing, spawning the field of phase- and polarization-tailored light. Here, we show that even in the fundamental case of 1D focusing using a cylindrical lens, symmetry-based phase tailoring of the input field can result in novel features. Dividing the beam or utilizing a π phase shift for half the input light along the non-invariant focusing direction, these features include a transverse dark focal line and a longitudinally polarized on-axis sheet. While the former can be used in dark-field light-sheet microscopy, the latter, similar to the case of a radially polarized beam focused by a spherical lens, results in a z polarized sheet with reduced lateral size when compared with the thickness of a transversely polarized sheet produced by focusing a non-tailored beam. Moreover, the switching between these two modalities is achieved by a direct 90° rotation of the incoming linear polarization. We interpret these findings in terms of the requirement to adapt the symmetry of the incoming polarization state to match the symmetry of the focusing element. The proposed scheme may find application in microscopy, probing anisotropic media, laser machining, particle manipulation, and novel sensor concepts.

PECULIARITIES OF REVEALING AND ESTIMATION OF AUSTENITIC GRAIN IN STRUCTURAL ALLOYED STEELS

Purpose. Establishing effective and correct techniques for detecting the grain structure in structural medium-carbon steels taking into account the recommendations of modern standards (ДСТУ ISO, ASTM, ГОСТ) with the aim of reliably determining the austenitic grain size and putting into operation of metal with the well-known and required, according to the normative technical documentation (technical requirements, drawings) quality.
 Research methods. Metallographic analysis of microstructure and evaluation of the austenitic grain size were carried out by comparing the image revealed on polished and etched using various chemical reagents microsections of heat-treatable steel 40KHN2МА-Ш with etalon of scale of standard.
 Results. Studies of structural alloyed steel 40ХН2МА-Ш found that the most effective etchant reagent, which best detects initial austenitic grain boundaries in medium-carbon alloyed steels, is a standard reagent - a saturated aqueous solution of picric acid. As a result of etching in this reagent, a visible image of the grain structure is formed in the form of a clear contrast of light areas of the grain body and dark lines of the grain boundaries, which allows a correct comparison of the structure with the images of the standards on the scales.
 Scientific novelty. On the example of heat- treatable steel 40ХН2МА-Ш, the ways of further development of ideas regarding the choice of an effective chemical reagent are considered for the purpose of detecting and forming a visible grain structure in accordance with the requirements of methodical standards in structural medium-carbon steels, proper and reliable estimation of austenitіс grain size using standard scale.
 Practical value. A correct procedure for detecting the initial austenite grain is proposed, which allows to reliably determine the grain size and quality from this parameter of various structural steels including for the production of responsible parts of aircraft and spacecraft.

Strobilanthes sripadensis, a new species of Acanthaceae from Sri Lanka

Strobilanthes sripadensis, a new species of Acanthaceae from Peak Wilderness Nature Reserve, Sri Lanka is described and illustrated. Both morphological and palynological evidence clearly indicate that S. sripadensis is a distinct species. The new species is closely related to S. pentandra, but differs by having short acuminate leaf apex, entire or slightly sinuate leaf margin, 5–7 pairs of lateral veins, outermost bract longer than the inner one, bract, bracteole, and calyx pubescent, white corolla with prominent dark purple lines at throat and fertile stamens 4.The full description, line drawings, photographs, and information on habitat and ecology, distribution, phenology are also provided. It is accessed to be Critically Endangered according to the IUCN Red List categories and criteria.

Transillumination facilitates coccygeal arterial cannulation in anaesthetised small-breed dogs.

Arterial access in small-breed dogs is challenging, but arterial visualisation may facilitate the procedure, as evidenced in human medicine. This prospective, randomised study investigated the result of using transillumination to guide coccygeal artery cannulation in small-breed dogs. Coccygeal artery cannulation was attempted in dogs anaesthetised with butorphanol, midazolam, propofol and sevoflurane. In 70 dogs (standard technique group [STECHNIQUE group]), arterial cannulation was performed using pulse palpation. In 71 dogs (transilluminating-standard technique group [TSTECHNIQUE group]), a transilluminating device was utilised. The device was placed on the dorsal tail, and the cannula was advanced towards the dark line visible against the bright background. If the artery was not well visualised due to pigmentation, pulse palpation was used. The success rate of arterial cannulation was compared between the groups using the chi-squared test. Arterial cannulation was significantly more successful (p < 0.001) in the TSTECHNIQUE group (63/71 [88.7%]) than in the STECHNIQUE group (43/70 [61.4%]). The number of punctures attempted and the time to cannulation were not assessed, and the procedure was only performed by veterinarians experienced in arterial cannulation. The transillumination allows for a more accurate approach to the coccygeal artery, improving the success of arterial cannulation when combined with pulse palpation.

Drosophilids with darker cuticle have higher body temperature under light

Cuticle pigmentation was shown to be associated with body temperature for several relatively large species of insects, but it was questioned for small insects. Here we used a thermal camera to assess the association between drosophilid cuticle pigmentation and body temperature increase when individuals are exposed to light. We compared mutants of large effects within species (Drosophila melanogaster ebony and yellow mutants). Then we analyzed the impact of naturally occurring pigmentation variation within species complexes (Drosophila americana/Drosophila novamexicana and Drosophila yakuba/Drosophila santomea). Finally we analyzed lines of D. melanogaster with moderate differences in pigmentation. We found significant differences in temperatures for each of the four pairs we analyzed. The temperature differences appeared to be proportional to the differently pigmented area: between Drosophila melanogaster ebony and yellow mutants or between Drosophila americana and Drosophila novamexicana, for which the whole body is differently pigmented, the temperature difference was around 0.6 °C ± 0.2 °C. By contrast, between D. yakuba and D. santomea or between Drosophila melanogaster Dark and Pale lines, for which only the posterior abdomen is differentially pigmented, we detected a temperature difference of about 0.14 °C ± 0.10 °C. This strongly suggests that cuticle pigmentation has ecological implications in drosophilids regarding adaptation to environmental temperature.