Dark Spots Research Articles

Synchrotron XAS study of Mn and Fe in Chinese blue-and-white Ming porcelains from the second half of the 15th century

The XAS analysis of a blue-and-white Ming porcelain's decorations has been used to elucidate the porcelain's production technology. The porcelain exhibits the typical blue decorations with dark spots that are constituted by dendritic aggregates enriched in Mn and Fe. The XAS revealed that during firing Mn2+ and Fe2+ ions diffused into the glaze and started to crystallize at 900 °C as rhodonite and hausmannite-jacobsite intermediate compounds. The study of the Fe XAS pre-edges provided to be a powerful tool to assess the redox record from the porcelain. The natural basalt calibration determined the Fe3+/ƩFe × 100 in the glaze and confirmed the oxidizing conditions during its production. Hence, the obtained XAS helped to elucidate the temperatures at which the wares were produced by identifying the porcelain's pigments and the redox conditions during their production. This novel approach can also be applied on a broad range of modern and archaeological ceramics to elucidate their production technology.

Heteroleptic Tin-Antimony Sulfoiodide for Stable and Lead-free Solar Cells

Summary The quaternary chalcogenide halides of group IV and V elements have attracted much attention due to their interesting semiconducting properties as well as a suitable band gap for solar cells. Here, for the first time, we report on solar cells using tin-antimony sulfoiodide (Sn2SbS2I3). Sn2SbS2I3 solar cells were fabricated using a chemical single-step deposition process with a solution containing a SbCl3-thiourea complex and SnI2 with the configuration of TiO2 and poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt-4,7-(2,1,3-enzothiadiazole)] as the electron- and hole-transporting layers, respectively. The best-performing cell exhibits a power conversion efficiency of 4.04% under the illumination of standard AM 1.5G conditions (100 mW cm−2). These unencapsulated cells exhibited good stabilities at 80% relative humidity, 85°C in air, and under illumination, respectively. These results provide guidelines for fabrication of lead-free heteroleptic perovskite solar cells by hosting divalent or combinations of monovalent and trivalent metal cations.

Superoscillatory metalens for an azimuthally polarized wave with different orbital angular momentum

Light beams with helical phase-fronts are attractive for many optical applications, such as optical tweezers, particle manipulation, and other optical applications. A superoscillatory metalens has been designed for an azimuthally polarized wave at a wavelength λ = 632.8 nm. Numerical simulation demonstrates that a superoscillation hollow dark spot is generated. The transverse inner FWHM is 0.358λ overcoming the diffraction limit, while the sidelobe ratio can be compressed to 18.3%. More importantly, for such incidence with different orbital angular momentum (OAM) l = 1, 2, and 3, the proposed metalens also presents elegant subwavelength tight focusing performances (the FWHMs are 0.469λ, 0.352λ, and 0.737λ, respectively). Extensive investigations have been made to present the unique characteristics of the generated foci, the phase distribution patterns are given for different OAM values. Small size and ultrathin thickness make such lenses suitable for various optical applications.

Taxonomic study of Moenkhausia cotinho Eigenmann, 1908 and Hemigrammus newboldi (Fernández-Yépez, 1949) with the description of two new speciesof Moenkhausia (Teleostei: Characiformes: Characidae).

Moenkhausia cotinho is redescribed based on the examination of meristic and morphometric data and external morphological characters of specimens from the Amazon and Orinoco basins and from rivers in the Guyana. The species is distinguished from congeners based on the combination of a reticulate color pattern, the presence of dark spots on the posterior edge of scales of the longitudinal rows dorsal to the lateral line, the presence of a dark blotch on the caudal-fin base failing to reach the posterior tip of the middle caudal-fin rays; the dorsal region of the eyes red to orange in life; 5/3 longitudinal series of scales, above and below the lateral line, respectively; and the tips of the pectoral-fin rays not extending beyond the base of the pelvic fin. All specimens of M. cotinho have a completely pored literal line except for a few specimens from drainages in the Guyana. The redefinition of the taxonomic limits and geographic distribution of M. cotinho allowed us to reevaluate the taxonomic limits and geographic distribution of Hemigrammus newboldi, the identity of which has been previously questioned, but which is clearly diagnosed from M. cotinho based on the relatively longer pectoral fin, the presence of conical teeth in the posterior portion of the dentary, the absence of a reticulate color pattern of body and in the shorter longitudinal dark stripe on body. In addition, two new species of Moenkhausia are described: Moenkhausia rondoni sp n. from the rio Madeira basin, Brazil and Moenkhausia pirahan sp n. from the lower rio Madeira and rio Trombetas and rio Tapajós basins, Brazil.

Usefulness of the Japan narrow-band imaging expert team classification system for the diagnosis of sessile serrated lesion with dysplasia/carcinoma.

Sessile serrated lesion (SSL) is a colorectal polyp that has malignant potential. However, the dysplastic components within an SSL can be difficult to diagnose with conventional endoscopy, because most SSLs with dysplasia/carcinoma have subtle mucosal features. Many studies have indicated that narrow-band imaging (NBI) observations of colorectal polyps are very useful, accurate predictors of histology. We aimed to verify the usefulness of the Japan NBI Expert Team (JNET) classification system for the diagnosis of SSLs with dysplasia/carcinoma. We examined 709 endoscopically or surgically resected lesions that were pathologically diagnosed as SSL, including 647 with no dysplasia, 37 with low-grade dysplasia, 15 with high-grade dysplasia, and 10 with submucosal invasive carcinoma. We retrospectively evaluated their clinicopathologic characteristics and conventional endoscopic and magnifying NBI endoscopic findings using the JNET system. Cases in all groups were more frequently located in the proximal colon. Submucosal invasive carcinomas were significantly larger than no dysplasia and low-grade dysplasia lesions. Almost all studied lesions (96.3%) were covered with a mucus cap. Five hundred and eighty (81.8%) lesions exhibited dark spots inside the crypts, which are NBI findings' characteristic of SSL. As for the JNET classification of magnifying NBI endoscopic findings, all 709 lesions showed Type 1. Six hundred and eighteen (95.5%) SSLs with no dysplasia lesions exhibited Type 1 only, whereas 52 (83.9%) SSLs with dysplasia/carcinoma had a combination of Type 1 and Type 2A, 2B, or 3, corresponding to SSL and dysplasia/carcinoma, respectively. The JNET classification had high sensitivity (83.9%), specificity (95.5%), and overall diagnostic accuracy (94.5%) for diagnosing SSLs with dysplasia/carcinoma. Use of magnifying NBI endoscopy with the JNET classification might be useful for diagnosing SSLs with dysplasia/carcinoma. This increased awareness may also improve the recognition of SSLs with dysplasia/carcinoma.

Inhibition of hexose oxidase on the dark spots in fresh wet noodle sheets: A feasible prevention of dark spots

Hexose oxidase was a feasible prevention for the dark spots in the fresh wet noodle sheets (FWNS). The chemical mechanism that hexose oxidase recucing the melanins of dark spots was discussed basis on the UPLC-TOF-MS analysis of the polyphenol oxidase (PPO)-catechol system. In the process of PPO browning, hexose oxidase catalyzed the oxidation of o-benzoquinone derivatives and their oligomers, hindering the formation of melanins. Hexose oxidase was efficient in FWNS with low ash content when water addition was 24%~44% or pH range was 4 ~ 7.5. Hexose oxidase could inhubit dark spots in the presence of 10 metal ions. The recommended addition amount was 40 ~ 60 ppm, by which the dark spots could be compolitely inhibited. Hexose oxidase was also suitable for wholewheat and oat FWNS, ΔL6d of wholewheat and oat FWNS were reduced by 4 and 7.98, respectively.

Correcting for chromatic stellar activity effects in transits with multiband photometric monitoring: application to WASP-52

Context.The properties, distribution, and evolution of inhomogeneities on the surface of active stars, such as dark spots and bright faculae, significantly influence the determination of the parameters of an orbiting exoplanet. The chromatic effect they have on transmission spectroscopy, for example, could affect the analysis of data from future space missions such asJames WebbSpace Telescope and Ariel.Aims.To quantify and mitigate the effects of those surface phenomena, we developed a modelling approach to derive the surface distribution and properties of active regions by modelling simultaneous multi-wavelength time-series observables.Methods.We present an upgraded version of theStarSimcode, now featuring the capability to solve the inverse problem and derive the properties of the stars and their active regions by modelling time-series data. As a test case, we analyse ~600 days ofBV RImultiband photometry from the 0.8-mJoan Oró(TJO) and 1.2-m STELLA telescopes of the K2 V exoplanet host star WASP-52. From the results, we further simulated the chromatic contribution of surface phenomena on the observables of its transiting planet.Results.UsingStarSimwe are able to determine the relevant activity parameters of WASP-52 and reconstruct the time-evolving longitudinal map of active regions. The star shows a heterogeneous surface composed of dark spots with a mean temperature of 575 ± 150 K lower than the photospheric value, with filling factors ranging from 3 to 14%. We used the results to study the chromatic effects on the depths of exoplanet transits obtained at different epochs and corresponding to different stellar spot distributions. In the case of WASP-52, which has peak-to-peak photometric variations of ~7% in the visible, the residual effects of dark spots on the measured transit depth of its giant planet, after applying the calculated corrections, are about 10−4at 550 nm and 3 × 10−5at 6μm.Conclusions.We demonstrate that by using contemporaneous ground-based multiband photometry of an active star, it is possible to reconstruct the parameters and distribution of active regions over time, thus making it feasible to quantify the chromatic effects on the planetary radii measured with transit spectroscopy and mitigate them by about an order of magnitude.

The Information Content in Analytic Spot Models of Broadband Precision Light Curves. II. Spot Distributions and Lifetimes and Global and Differential Rotation

Abstract With the advent of space-based precision photometry missions, the quantity and quality of starspot light curves has greatly increased. This paper presents a large number of starspot models and their resulting light curves to (1) better determine light-curve metrics and methods that convey useful physical information and (2) understand how the underlying degeneracies of the translation from physical starspot distributions to the resulting light curves obscure that information. We explore models of relatively active stars at several inclinations while varying the number of (dark) spots, random spot distributions in position and time, timescales of growth and decay, and differential rotation. We examine the behavior of absolute and differential variations of individual intensity dips and overall light curves and demonstrate how complex spot distributions and behaviors result in light curves that typically exhibit only one or two dips per rotation. Unfortunately, simplistic “one- or two-spot” or “active longitude” descriptions or modeling of light curves can often be highly misleading. We also show that short “activity cycles” can easily be simply due to random processes. It turns out to be quite difficult to disentangle the competing effects of spot lifetime and differential rotation, but under most circumstances, spot lifetime is the more influential of the two. Many of the techniques tried to date only work when spots live for many rotations. These include autocorrelation degradation for spot lifetimes and periodograms for both global and differential rotation. Differential rotation may be nearly impossible to accurately infer from light curves alone unless spots live for many rotations. The Sun and solar-type stars its age or older are unfortunately the most difficult type of case. Further work is needed to have increased confidence in light-curve inferences.

PIGMENTED ORAL LICHEN PLANUS: A CASE REPORT

Oral lichen planus (OLP) is a mucocutaneous disease affecting up to 4% of the world population. Essentially there are 2 forms of oral lesions: reticular and erosive. Mucosal pigmentation is common in dark-skinned individuals, often associated with inflammatory conditions such as active OLP. A 67-year-old female ex-smoker with hypertension and diabetes was referred for evaluation of mouth spots with 10 years of duration. During skin examination dark spots scattered throughout the legs were observed. Intraoral examination revealed interlacing white lines and papules in a melanocytic-pigmented background located bilaterally in the buccal mucosa, lateral border, and dorsum of tongue, symmetric and painless. Pigmented-OLP clinical diagnosis was confirmed by histopathology. The patient has been followed up and continues without complaints. This case illustrates a common association with oral melanocytic-pigmentation such as that indicative of inflammatory behavior of OLP and the importance of patient follow-up because of OLP exacerbation. Oral lichen planus (OLP) is a mucocutaneous disease affecting up to 4% of the world population. Essentially there are 2 forms of oral lesions: reticular and erosive. Mucosal pigmentation is common in dark-skinned individuals, often associated with inflammatory conditions such as active OLP. A 67-year-old female ex-smoker with hypertension and diabetes was referred for evaluation of mouth spots with 10 years of duration. During skin examination dark spots scattered throughout the legs were observed. Intraoral examination revealed interlacing white lines and papules in a melanocytic-pigmented background located bilaterally in the buccal mucosa, lateral border, and dorsum of tongue, symmetric and painless. Pigmented-OLP clinical diagnosis was confirmed by histopathology. The patient has been followed up and continues without complaints. This case illustrates a common association with oral melanocytic-pigmentation such as that indicative of inflammatory behavior of OLP and the importance of patient follow-up because of OLP exacerbation.

XERODERMA PIGMENTOSUM: A CASE REPORT OF AN INTERESTING GENETIC CONDITION

A 14-year-old female patient was referred to the oral diagnostic service in 2018 for evaluation of a dark spot on the gingiva between teeth 41 and 42. The medical report from a clinical genetics service described in detail the medical history of the girl and her sister, daughters of parents who are cousins of each other. The girls have xeroderma pigmentosum, a rare and incurable genetic disease with autosomal recessive etiology. It is characterized by solar hypersensitivity associated with the development of numerous cutaneous pigmentations on the face and arms. Both sisters have other characteristics common in 25% of affected patients, such as photophobia and progressive cognitive deficit. Intraoral biopsy was performed immediately because of increased risk for development of cutaneous neoplasms, including melanoma. The result indicated melanocytic macula. After evidence of benign lesion in the gingiva, the sisters are monitored and protect themselves with use of sunscreen and few exits from home. A 14-year-old female patient was referred to the oral diagnostic service in 2018 for evaluation of a dark spot on the gingiva between teeth 41 and 42. The medical report from a clinical genetics service described in detail the medical history of the girl and her sister, daughters of parents who are cousins of each other. The girls have xeroderma pigmentosum, a rare and incurable genetic disease with autosomal recessive etiology. It is characterized by solar hypersensitivity associated with the development of numerous cutaneous pigmentations on the face and arms. Both sisters have other characteristics common in 25% of affected patients, such as photophobia and progressive cognitive deficit. Intraoral biopsy was performed immediately because of increased risk for development of cutaneous neoplasms, including melanoma. The result indicated melanocytic macula. After evidence of benign lesion in the gingiva, the sisters are monitored and protect themselves with use of sunscreen and few exits from home.

Enhanced monoterpene emission in transgenic orange mint (Mentha × piperita f. citrata) overexpressing a tobacco lipid transfer protein (NtLTP1).

Overexpression of the tobacco lipid transfer protein (NtLTP1) gene in transgenic orange mint resulted in enhanced accumulation of monoterpenes in the cavity of head cells of glandular trichomes, which resulted in enhanced emission of monoterpenes from transgenic orange mints. Plants in the genus Mentha (Lamiaceae) produce volatile oils that accumulate in peltate glandular trichomes in the aerial parts of plants. A lipid transfer protein (NtLTP1) in tobacco showed glandular trichome-specific expression and supported the secretion of diterpenoid lipids from head cells of glandular trichomes (Choi et al., Plant J 70:480-491,2012). Here, we constructed transgenic orange mint (Mentha × piperita f. citrata) overexpressing the tobacco NtLTP1 gene via Agrobacterium-mediated transformation. Transgenic lines of orange mint overexpressing NtLTP1 were confirmed by genomic PCR and RT-PCR. Immunoblotting analysis using an NtLTP1 polyclonal antibody showed clear dark spots at the position of the lipid exudates from tobacco glandular trichomes and the squeezed out lipids from the glandular trichomes of transgenic orange mint. Heads of glandular trichomes in transgenic plants overexpressing the NtLTP1 gene showed a larger diameter than those of the wild-type control. The enhanced size of trichome heads in transgenic orange mint was confirmed by scanning electron microscopy. Volatile components were extracted from wild-type and transgenic orange mint by solid-phase microextraction (SPME) and analyzed by headspace-gas chromatography-mass spectrometry (HS/GC/MS). Linalyl acetate was the most abundant component among the eleven identified monoterpenes in the volatile compounds extracted from both the wild-type and transgenic lines of orange mint. Overexpression of NtLTP1 in transgenic orange mint plants resulted in enhanced emission of volatile monoterpenoids compared with that of volatile monoterpenoids in the wild-type control plants.

Interaction mechanism between nanoparticles and ultra-smooth surface under effect of cavitation

During the nanoparticle colloid jet polishing process to obtain ultra-smooth surface, cavitation is easy to occur because of the intense fluid turbulence. Cavitation interacts with nanoparticles in the colloid solution, which has a great influence on the processing quality of the ultra-smooth surface. In this paper, the collision between nanoparticles and ultra-smooth surfaces under the micro-jet effect formed by cavitation is studied. Molecular dynamics simulation result shows that the collision of nanoparticles changes the atomic position of the collision region of workpiece, resulting in lattice distortion, coordination number and atomic potential energy increased. The ultrasonic cavitation system is used to prepare the monocrystalline silicon workpiece that effected by nanoparticle colloid cavitation. After the process, the dark spots could be observed on the surface of workpiece by SEM. The dark spots are the traces of the collision between the nanoparticle and workpiece, which verify the molecular dynamics simulation results. XPS detection of the surface of monocrystalline silicon workpiece processed by nanoparticle colloid cavitation has been done and the result is slightly different from the workpiece that have not been processed by cavitation. The difference illustrates that the chemical bonding between nanoparticles and monocrystalline silicon surfaces has formed. The simulation and experimental results show that the cavitation is beneficial to the removal of the material of the workpiece by nanoparticles, but it has an adverse effect on the formation of ultra-smooth surface.

Case report: the first case of unilateral retinal pigment epithelium dysgenesis in China

BackgroundUnilateral retinal pigment epithelium dysgenesis (URPED) is a rare condition and is characterized by a unilateral and solitary lesion in the peripapillary region. The lesion presents with central atrophy, peripheral fibrosis, and hyperplastic changes in the retinal pigment epithelium (RPE). Herein, we report the first case of URPED in a Chinese individual using multimodal imaging techniques such as en-face optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA).Case presentationA 10-year-old girl presented with 20/40 vision in her left eye. Presented as a solitary, unilateral, large and yellowish-white lesion, with fringe-like margins was observed in the posterior pole and lower middle periphery of the left eye continuous with the optic nerve, indicated URPED. Infrared fundal (IR) images showed that the fringe-like contour of the lesion was visible, with diffuse hyperreflective signals specifically in the fovea, while with peripheral dark spots, having a typical leopard-spot like appearance. Fundus autofluorescence (FAF) revealed a markedly scalloped lesion containing a hypoautofluorescence area mixed with an isoautofluorescence area. Spectral-domain optical coherence tomography (SD-OCT) revealed the outer segments of photoreceptors presented with an inhomogeneous signal in the fovea, with a weak local signal. The ellipsoid and interdigitation zones were thinner than normal, while the RPE/Bruch’s complex was not flat, with locally visible protrusions. En-face OCT image at the level of the RPE zone showed a mottled hyperreflective signal with peripheral hyporeflective spots, fringe-like margin lesions. OCTA of the avascular area of the fovea in the superficial, deep, and outer retinal layers appeared to be oval in shape, the choroid capillary layer revealed an increase in the density of the choroidal vasculature in the fovea.ConclusionsThis is the first report on URPED in China. Both en-face OCT and OCTA were essential in observing and studying the disease. Further investigation is required to better define the en-face OCT and OCTA features of URPED and clarify the disease characteristics and prognosis.

STM and STS studies of topological n-type (Bi, In)2(Te, Se, S)3 thermoelectrics

In topological n-type thermoelectrics based on Bi2Te3 with atomic substitutions Bi → In, Te → Se, S, the morphology and the surface states of Dirac fermions on the interlayer (0001) surface of van der Waals were studied by scanning tunneling microscopy and spectroscopy (STM/STS) techniques. By the STM method, the dark and light spots on the surface were found, which intensities depend on the composition and thermoelectric properties of solid solutions such as the Seebeck coefficient and thermoelectric power factor. The observed surface morphology features in the solid solutions are explained by distortions of surface electronic states originated from atomic substitutions, the influence of doping impurity, and formation mainly of substitutional impurity defects in thermoelectrics. The dips associated with substitutional impurities and antisite defects were found from the analysis of the height profiles obtained on the (0001) surface. Fast Fourier transform of the morphology STM images of the (0001) surface were used to obtain the interference patterns of the quasiparticles excitation caused by surface electrons scattering by defects. The Dirac point energy and its fluctuations, peak energies of surface defects, the positions of the valence and conduction band edges, and the energy gap were determined from an analysis of tunneling spectra. A correlation between the parameters of surface states of Dirac fermions and thermoelectric properties was found. Thus, a contribution of the fermions surface states increases with rise of the surface concentration in solid solutions with high power factor, and the largest concentration value was observed in the Bi1.98In0.02Te2.85Se0.15 composition. The dependences of Fermi energy on the wave vector for different solid solutions are described by a set of Dirac cone sections located within the limits of the fluctuations of the Dirac point energy that explained by weak changes of the Fermi velocity for studied atomic substitutions in sublattices of bismuth telluride.

A new species of Corcyrogobius (Teleostei: Gobiidae) from Île de Ngor, Senegal.

Corcyrogobius pulcher sp. nov. is described from off Île de Ngor, Dakar, Senegal. Corcyrogobius pulcher is distinguished from its two congeners by having the rear edge of the jaws ending posteriorly below mideye, second dorsal fin I/9, pectoral fin rays 17, pelvic fins oval or truncated posteriorly, scales in lateral series 26-27, anterior oculoscapular head canal with pore β, suborbital row b of sensory papillae anteriorly beginning below vertical of posterior edge of eye, dark vertical caudal bar, branchiostegal membrane without intense dark spot, cheek with two oblique whitish stripes, the first going from the eye downwards and forward to the posterior jaws, the second on the preopercular, alternating with brown oblique stripe going from behind the eye downwards and forward across the cheek. Furthermore, mitochondrial COI-barcoding data unambiguously support the species-level distinctiveness of the three Corcyrogobius species. A key to the species of Corcyrogobius is provided.

Egg spottiness reflects female condition, physiological stress, and ornament expression in a common rallid species

Lay Summary • There is equivocal support for direct associations between maternal quality and deposition of protoporphyrin pigmentation (dark spots and blotches) in avian eggshells. • Research on protoporphyrin eggshell pigmentation has primarily focused on a single avian order (Passeriformes). • We examined associations of protoporphyrin-based eggshell pigmentation with female phenotypic and genetic traits in a non-passerine species, the Eurasian Coot. • Deposition of protoporphyrin in eggshells (total number per area of egg spots) positively correlated with female condition and expression of a putative bare-part ornament (frontal shield), while it was negatively associated with the level of physiological stress. • Protoporphyrin-based eggshell pigmentation acts as a reliable signal of female phenotypic (but not genetic) traits in the Eurasian Coot. • Signaling properties of protoporphyrin-based egg coloration are likely to largely differ between different evolutionary lineages of birds.

Logging identification and evaluation of vertical zonation of buried hill in Cambrian dolomite reservoir: A study of Yingmai-Yaha buried hill structural belt, northern Tarim basin

Buried hill reservoir is indispensable part of karst reservoirs in northern Tarim basin, China, which is resulted from the long-term exposure of Cambrian carbonate rock due to meteoric freshwater. Four types of zones could be divided in the buried hill of Upper Cambrian Xiaqiulitage Formation in Yingmai-Yaha structure, including surface karst zone, vertical vadose zone, horizontal underflow zone and deep slow flow zone from up to bottom. Firstly, the conventional and image log response characteristics of different types of vertical karst zonation were summarized through cores, thin section and well log-calibration. The surface karst zone is close to the weathering crust, showing breccia and residual characteristics, and is recognized as bright spots appearances on the image logs. Due to the vertical movement of atmospheric fresh water, a large number of high-angle fractures and dissolution caves are developed in the vertical vadose zone, and the vertical vadose zones are characterized by high-angle sine curve appearances on the image logs. The horizontal under flow zone has a horizontally connected caves or vugs due to the horizontal movement of groundwater, and the image logs are recognized as dark bands. The conventional logs also show the decrease of resistivity and the increase of gamma ray (GR). The deep slow flow zone is less affected by karstification, and there are fewer dissolution caves and fractures, but there is also a certain weak dissolution and may contain small vugs. The image logs show isolated dark spots. The Vertical zonation of buried hill can be divided using well logs by calibrating cores, and thin sections. Finally, the core analysis, and the oil test data are used to determine the zoning of the high-quality reservoir. The results show that the four zones of the buried hills have obvious well log response characteristics. The karst zoning can be well divided by the image logs and conventional well logs when calibrated with cores. The data of core analysis and oil testing show that although the reservoir quality in the horizontal underflow zone is the best, the study area is a bottom-water reservoir, and the reservoirs in the horizontal underflow zone are mainly water-producing. On the contrary, in the vertical vadose zone, a large number of high-angle fractures communicated with small pores, which not only improved the quality of the reservoir, but also the oil test data proves that the reservoir is mainly producing oil and gas. Therefore, compared with the horizontal underflow zone and deep slow flow zone, the vertical vadose zone is favorable to the enrichment and preservation of oil and gas. The research results will provide important insights in the hydrocarbon exploration and exploitation in dolostone reservoirs of Tarim Basin.

Dung mimicry: the function of volatile emissions and corolla patterning in fly-pollinated Wurmbea flowers.

It has been suggested that flowers of some angiosperms mimic vertebrate faeces (dung) in order to exploit insect pollinators that utilize faeces as a source of food and/or oviposition sites. We investigated a potential case of mimicry in Wurmbea elatior (Colchicaceae), a lily that exhibits a faecal odour and pattern of dark spots on the corolla. We found that W.elatior is pollinated by a broad assemblage of coprophagous flies and is dependent on pollinator visits for seed production. The flowers emit volatiles that are characteristic of vertebrate faeces, and three of these compounds - skatole, indole, and an unidentified compound - elicited electrophysiological antennal responses from flies. Artificial flowers laced with indole and skatole or skatole alone attracted the same assemblage of flies as was recorded on flowers of W.elatior. Spotted artificial flowers attracted twice as many flies as did those lacking spots. Experimental addition of indole and skatole to flowers of Wurmbea kraussii, a congener with unscented flowers pollinated by hoverflies, induced a shift to an insect visitor assemblage dominated by coprophagous flies. This study clarifies the roles of volatile emissions (particularly skatole) and visual signals in floral dung mimicry.

Mechanisms formation of systemic acquired resistance in spring barley plants (<i>Hordeum vulgare</i> L.) during infection by the pathway of dark brown spot

The physiological and biochemical responses in spring barley plants to infection with a hemibiotrophic phytopathogenic fungus B. sorokiniana was studied. It was found that these responses of the plant organism are regulated by signaling pathways with the participation of the salicylic acid mediator (SA) and are associated with oxidative stress-localized accumulation of reactive oxygen molecules (ROS) in infected cells and/or neighboring cells. The activation of the microsomal fraction of NADPH oxidase isolated from barley leaves on days 1 and 3 after fungal infection was revealed, which is known to be responsible for the rapid formation of ROS in plant cells under the influence of fungal infection. At the same time, an increase in the activity of the peroxidase enzyme detoxifying ROS, in particular Н 2 О 2 , was observed in relation to the control (uninfected plants) by 1.6 and 2.2 times on the 1st and 3rd day after exposure, respectively. The inclusion of antioxidant defense mechanisms led to the stabilization of lipid peroxidation processes several days after infection. A reliable increase in the total content of water-soluble phenolic substances in the infected plant tissues was shown to have a protective effect on plants under stress, as well as an increase in the free pool of endogenous SA by 9 and 30 % during the first 24 hours and the next 3 days after infection, respectively. The data obtained indicate that endogenous S А is involved in the responses to infection of B. sorokiniana barley seedlings and is a necessary factor for the activation of SAR (systemic acquired resistance), which manifests itself in the accumulation of free S А and a decrease in its conjugated form in response to infection.

Effect of fluoride agents on surface characteristics of NiTi wires. An ex vivo investigation

AimTo analyze the degree of corrosion of nickel titanium arch wires in patients with and without exposure to fluorides. Material and methodsThis was an ex vivo study comprising of 60 subjects undergoing fixed orthodontic treatment. Group 1(controls) comprised of 30 sets of new unused NiTi wires and unused 11, 15 brackets, Group 2(patients) comprised of 30 sets of non fluoridated NiTi wires and 11, 15 brackets and Group 3(patients) had 30 sets of fluoridated NiTi wires and 11, 15 brackets. NiTi wires were used over 6 months of treatment(0.014″,0.016″, 16 × 22”, each wire was used for 2 months and replaced with the next size). All wires were retrieved, stored and analyzed. At 6 months, brackets from 11 to 15 were debonded in both treatment groups. Archwires and brackets in 3 groups were subjected to SEM analysis at 500 and 1000X to observe differences. Additionally, EDX Spectroscopy was undertaken to evaluate surface elemental compositional differences in groups. ResultsSignificant differences among groups were evident in brackets and archwires tested. Maximum degradation, cracks and dark spots were seen in wires and brackets exposed to fluoride agents. EDX spectroscopy revealed least Ni% in fluoridated wires and brackets. ConclusionsIncreased leaching of metal ions was evident when wires and brackets are exposed to fluoride agents during treatment. Use of non fluoridated mouthwash and toothpastes may be considered in orthodontic patients without risk of caries to mitigate such effects