Yellow Orange Research Articles

UV–Vis-NIR and micro Raman spectroscopies for the non destructive identification of Cd1 − xZnxS solid solutions in cadmium yellow pigments

Commercially available since the 1840s, cadmium zinc sulfides were extensively employed by the nineteenth and twentieth century artists. The term cadmium sulfide refers to a number of yellow–orange–red compounds sharing a common structure based on CdS where various elements including Zn, Hg, Se, may substitute for Cd or S, producing a variety of hues. In fact, their chromatic properties are linked to the fact that CdS is a semiconductor with a direct band gap of 2.42eV that can be modulated by the progressive substitution of Cd e.g. with Zn to give pale yellow cadmium zinc sulfide pigments. The aim of this paper was to develop an analytical methodology based on the combination of electronic and vibrational spectroscopies for the non destructive identification of different forms of yellow Cd1−xZnxS solid solutions. The methodology was optimized on six commercial CdS-based pigments and then applied and tested on four historical pigments from the early twentieth century. The complete set of commercial and historical samples has been investigated through X-ray fluorescence, microRaman, UV–Vis-NIR reflection, Vis-NIR emission spectroscopies and X-ray diffraction. The optical properties were investigated exploring i) the reflection behavior in the visible range and ii) the emission profiles in the visible and near infrared ranges correlating the results with the pigment composition. On the other hand, microRaman spectroscopy proved to be a sensitive probe of the short range disorder generated by Zn substitution. The availability of different Raman laser excitations (488, 514, 633 and 785nm) permitted, depending on the optical band gap value of each pigment, to record both on- and off-resonance Raman spectra giving information on the stoichiometry of the solid solutions and on their local structure in fairly good agreement with XRD analysis.

Hypericum: An antidepressant traditional Western herb

Hypericum's complete botanical name is Hypericum perforatum. Perforatum is Latin for perforated. The flowers are a bright yellow orange. It has served as a sedative, painkiller, and analgesic. The blossoms have been added to sweek oil (a refined olive oil used medicinally) for a soothing dressing for cuts. Herbalists credit it with increasing and inducing a sense of well-being. Hypericum is available in tablets, capsules, drops and teas. It is also available as an oil for external use. The oil cannot be recommended for internal use as an antidepressant. In a study of 3,250 patients taking hypericum, only 2.4 percent experienced any side effects at all. The side effects reported tended to be mild. Gastrointestinal irritations accounted for 0.6 percent, allergic reactions for 0.5 percent, tiredness for 0.4 percent, and restlessness for 0.3 percent. It is a rhizomatous perennial herb upto 3 ft.high, distributed in the western Himalayas at altitudes of 3000-10500 ft.

Synthesis and luminescence characterization of Sr0.5Ca0.5TiO3:Sm3+ phosphor

The spectroscopic properties of trivalent samarium doped Sr0.5Ca0.5TiO3 perovskite phosphor material (Sr0.5Ca0.5TiO3:xSm3+, x=0.05, 0.1, 0.5, 1, 1.5) synthesized by the solid state method have been studied. The X-Ray Diffraction profile confirms the orthorhombic perovskite Sr0.5Ca0.5TiO3 structure of the prepared samples. The SEM study reveals the surface morphology. The Judd–Ofelt intensity parameters were calculated for 0.5wt% Sm3+ doped Sr0.5Ca0.5TiO3. Transition probabilities, branching ratios and radiative lifetime were evaluated by using Judd–Ofelt analysis. The emission spectra under 405nm excitation shows five emission peaks at 564nm, 599nm, 645nm, 707nm and 776nm corresponding to the transitions 4G5/2→6Hj (j=5/2, 7/2, 9/2, 11/2 and 13/2) respectively. The higher values of branching ratio and stimulated emission cross-section for 4G5/2→6H7/2 transition of Sr0.5Ca0.5TiO3:0.5wt% Sm3+ shows its suitability in the field of visible lasers and optical fiber amplifiers. The experimental lifetimes of Sm3+ doped samples were estimated using the decay curves corresponding to 4G5/2→6H7/2 transition upon 405nm excitation. Concentration dependence on emission intensity and experimental lifetime were also studied. From the CIE diagram we can see that as the concentration of Sm3+ ions increases from 0.05wt% to 1.5wt% the CIE color co-ordinates changes from greenish yellow to yellowish orange.

Low-temperature synthesis of freudenbergite-type titanate bronzes from metal halides, crystal growth from molybdate flux, and crystal structure determination of Na1.84Zn0.92Ti7.08O16

A new precipitation method to synthesize freudenbergite-type phases from metal halides has been developed, and titanate bronzes of the general formula NaxMyTi8−yO16 with M=Fe, Zn were obtained as micro-crystalline powders (Fe: orange–yellow, Zn: colorless). The crystal structures were refined based on synchrotron X-ray data using the Rietveld method. Single crystals of the new compound Na1.848(8)Zn0.924(3)Ti7.076(3)O16 were grown from molybdate flux, and its crystal structure was determined (s.g. C2/m, No. 12, a=1230.2(2)pm, b=381.94(4)pm, c=650.2(2)pm, and β=107.09(2)°). It is isostructural to the Fe-containing freudenbergite-type phase. Absorption spectra from diffuse reflection measurements are shown.

Chryseobacterium shandongense sp. nov., isolated from soil.

YF-3T is a Gram-stain-negative, non-motile, non-spore-forming, yellow-orange, rod-shaped bacterium. Optimal growth conditions were at 30 °C, pH 7.0 and 1 % (w/v) NaCl. Phylogenetic analysis, on the basis of the 16S rRNA gene sequence, showed that strain YF-3T was closely related to the strains Chryseobacterium hispalense AG13T and Chryseobacterium taiwanense Soil-3-27T with 98.71 % and 96.93 % sequence similarity, respectively. Strain YF-3T contained MK-6 as the main menaquinone and had a polyamine pattern with sym-homospermidine as the major component. Its major polar lipid was phosphatidylethanolamine. The dominant fatty acids of strain YF-3T were iso-C15 : 0, iso-C17 : 0 3-OH, summed feature 9 (comprising iso-C17 : 1ω9c and/or C16 : 0 10-methyl) and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c). The DNA G+C content of strain YF-3T was 37 mol%. The DNA-DNA relatedness levels between strain YF-3T and the most closely related strains, C. hispalense AG13T and C. taiwanense Soil-3-27T, were 31.7 ± 2.1 % and 28.4 ± 5.4 %, respectively. Based on these results, a novel species named Chryseobacterium shandongense sp. nov. is proposed. The type strain is YF-3T ( = CCTCC AB 2014060T = JCM 30154T).

Pigmentation of Serratia marcescens and spectral properties of prodigiosin

Pigmentation of Serratia marcescens depends on the composition of the cultivation medium. The cultures grown on glycerol-peptone medium and on the medium with acetate are red and yellow (yellowish orange), respectively, with the color depending on the ambient pH. S. marcescens cells growth on glycerol-peptone medium (visually of red color) contain two forms of prodigiosin: the "red" and "yellow" ones with absorption maxima at 535 and 460-470 nm, respectively. The absorption spectrum of prodigiosin in the native pigment-protein complex was different from the spectrum of the pigment dissolved in ethanol and resembled that of the cell suspension in the presence of an additional absorption maximum at 500 nm.

Er3 +/Sm3 +- and Tb3 +/Sm3 +-doped glass phosphors for application in warm white light-emitting diode

Tunable polychromatic light emission within the low correlated color temperature range was produced using terbium- and/or erbium–samarium co-doped PbGeO3:PbF2:CdF2 glass phosphor. The phosphors were synthesized, and their luminescence characteristics were examined under UV–blue light-emitting-diode laser excitation. Luminescence emissions around 490, 545, 600, and 645nm in Tb3+/Sm3+ co-doped phosphor and 525, 545, 600, and 645nm in Er3+/Sm3+ co-doped phosphor were obtained and analyzed as a function of the active ion concentration and excitation wavelength. Color tunability in the red–orange–yellow–green region was achieved combining the Tb3+, Er3+, and Sm3+ active ion contents. Results suggest that the color-tunable polychromatic light emitter herein reported is a promising candidate for application in warm white-light emission.

Gold Nanoparticles Loaded on Activated Carbon as Novel Adsorbent for Kinetic and Isotherm Studies of Methyl Orange and Sunset Yellow Adsorption

In this research, a novel adsorbent gold nanoparticle loaded on activated carbon (Au-NP-AC) was synthesized by a low cost in a routine protocol. Subsequently, this novel material characterization and identification are followed by different techniques such as th eBruner–Emmet–Teller (BET) theory, scanning electron microcopy, and transmission electron microscopy analysis. Unique properties such as high BET surface area (>1229.55 m2/g) and low pore size (<22.46 Å) and average particle size lower than 48.798 Å in addition to high reactive atom and presence of various functional groups make it possible for efficient removal of sunset yellow (SY) and methyl orange (MO). Generally, the influence of variables including amount of adsorbent, initial dyes concentration, contact time, temperature on dyes removal percentage has great effect on removal percentage that their influence was optimized. The kinetic of proposed adsorption processes efficiently followed, pseudo-second-order and intra-particle diffusion approach. The equilibrium data of the removal strongly follow the Langmuir monolayer adsorption with high adsorption capacity in a short amount of time. This novel adsorbent by small amount (0.01 g) really is applicable for removal of high amount of both dyes (MO and SY) in short time (<18 minutes). Equilibrium data fitted well with the Langmuir model at all amount of adsorbent, while maximum adsorption capacity for MO 161.29 mg g−1 and for SY 227.27 for 0.005 g of Au-NP-AC.

Biodiversity and Landscape Use of Sea Buckthorn (Hippophae rhamnoides L.) in the Coruh Valley of Turkey

The Sea buckthorn, one of the most important wild edible fruits widely grown in Northeastern part of Turkey, is characterized by resistance to hard environmental conditions and looks spectacular, especially in autumn and winter when it is decorated with orange berries. Climatic conditions in Northern Anatolia are suitable for the growing of the Sea buckthorn, which can be encountered in various dry areas as well as by riversides. Local people traditionally processed or preserved sea buckthorn fruits (berries). The decorative sea buckthorn shrubs/trees and berries are an important element of natural landscape in Northeastern Anatolia. The aim of the study was to define the biodiversity among trees/shrubs, berries and leaves of the Sea buckthorn accessions based on morphological and biochemical data. Results showed a high diversity among accessions in terms of plant, leaf and berry characteristics. Berry diameter, length and 100 berry weight ranged from 5.48 to 7.18 mm; 6.64 to 9.14 mm and 15 to 26 g, respectively. A wide variability of berry skin colour was observed to be yellow, light yellow, dark yellow, yellow orange, orange and dark orange. The anthocyanin content varied from 7 to 38 mg/l berry juice.

Screening of African marigold (Tagetes erecta L.) for novelty

An investigation was carried out to screen the African marigold genotypes for novel characters such as different flower form, colour intensity, flower compactness, plant stature and presence of gynomonoecious sex from. Among the 28 African marigold genotypes one pure double, ten semi double, one single flower form and sixteen mixture of double, semi double and single flower forms were noticed. Among the genotypes, flower colour intensity of marigold genotypes varied from yellow, greenish yellow, yellow orange and orange. Siracole produced highly firm, compact, round flowers with high score of 5.00 followed by Double Orange while least flower compactness and loose flower head was recorded in Sathy Local Orange. Plant stature was classified into three categories and among the 28 genotypes one dwarf, eleven semi tall and sixteen tall genotypes were recorded. The variation in plant stature is due to the inherent genetic character. Gynomonoecy is the sexual system in which individual plants bear both female and bisexual flowers was noticed in the genotype Siracole. Wide variation and novelty noticed in the African marigold germplasm may be utilized for further improvement programmes.

Growth of laser diode structures with emission wavelength beyond 1100 nm for yellow–green emission by frequency conversion

Laser structures for emission wavelengths of 1120nm and 1180nm, suitable for non-linear frequency conversion to yellow–green and yellow–orange, were developed. At 1120nm emission wavelength different active regions and structures were investigated. The introduction of a GaAs spacer layer between GaAsP barriers and InGaAs QWs reduces threshold and transparency current density significantly. Lifetime measurements were done successfully over 1700h for broad area and 10000h for ridge waveguide tapered lasers.Broad area laser diodes with a partly strain-compensated 6nm InGaAs QW, emitting at 1180nm, show lifetimes above 1000h at an output power of 1.5W. The required beam quality was achieved by processing a ridge waveguide laser with an included distributed Bragg reflector. Such a laser emits up to 200mW in single mode output power.

Rapid adsorption of binary dye pollutants onto the nanostructred mesoporous alumina

In this study ordered mesoporous alumina (OMA) with pore size of about 5nm has been used for removal of dye pollutants from binary systems including methyl orange+bromothymol blue, methyl orange+reactive yellow and methyl orange+methyl violet. Derivative spectrophotometry was used for simultaneous determination of the dyes concentrations. The results show that OMA is a good adsorbent for rapid removal of dyes (especially anionic ones) from aqueous solution. Characterization of OMA has been performed by TEM and XRD techniques. The adsorption kinetic data of binary dye mixtures follows the competitive statistical rate theory (SRT) model well.

Controlled hydrothermal growth and tunable luminescence properties of β-NaYF4:Yb3+/Er3+ microcrystals

Using a facile hydrothermal method, hexagonal β-NaYF4:Yb3+ 20mol%, Er3+ 1mol% crystals with predictable size and morphology were synthesized and the upconversion (UC) luminescence properties were investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectra were used to characterize the samples. The results indicated that the size and morphology of the crystals can be precisely controlled by tuning the pH values of the initial reaction solution and the molar ratio of NaNO3 to RE3+ (RE=Y+Yb+Er), and the mechanism was proposed. The UC luminescence properties of β-NaYF4:Yb3+/Er3+ crystals were found to strongly depend on the crystal morphologies and sizes. The peak area ratio of green to red (R/G) increased from 0.29 to 1.03 with pH values increasing from 3 to 10, and increased from 1.03 to 1.26 with the increase of molar ratio of NaNO3 to RE3+ from 0 to 90. The emission colors were tuned from pure green to orange yellow. This study provides a facile way to synthesize β-NaYF4:Yb3+/Er3+ crystals with predictable morphology and size, and tunable luminescence properties, which can be applicable for other rare earth fluoride compounds.

Two new genera of Arthoniales from New Caledonia and the Solomon Islands, with the description of eight further species

Two new genera in the Arthoniales are described from the Pacific Islands. Glyphopsis, with the new species G. aurantiodisca from New Caledonia is characterized by a thallus containing divaricatic acid and zeorin and sessile grouped ascomata with bright orange discs and raised lecanorine margins, and the ascospores hyaline and muriform. Gossypiothallon, with the new species G. appendisporum from the Solomon Islands is characterized by a byssoid thallus containing zeorin and pedicillate, simple ascomata with pale pink discs, without differentiated margins and hyaline, bacillar, 3-septate ascospores with two polar, usually curved gelatinous appendages. Eight further corticolous crustose lichens are described from either New Caledonia or the Solomon Islands. Byssoloma xanthonicum is characterized by a thallus containing norstictic acid and lichexanthone and 3-septate ascospores. Cliostomum ovocarpum has orange yellow, convex apothecia and 1-septate ascospores. Crocynia minutiloba has palmately branched lobes on a thick whitish byssoid hypothallus and flat lecideoid apothecia. Megalotremis dolabarata has superficial cylindrical grey pycnidia and simple ellipsoid conidia. Pyrenula filiformis has a thallus with pseudocyphellae covering most part of the ascomata and 11–17-septate, slender fusiform to slightly clavate ascospores. Pyrenula mastigophora has 5-septate ascospores with an up to 25 µm long tail at the lower end. Pyrenula spissitunicata has a thallus with lichexanthone, fused ascomata with common ostioles covered by thallus and ascospores resembling a Pyrgillus. The lichenicolous fungus Pyrenidium coccineum (parasitic on Siphula decumbens) has red ascomata which stain herbarium boxes blue.

Loktanella variabilis sp. nov., isolated from a tidal flat.

Two Gram-negative, aerobic and rod-shaped or ovoid bacterial strains with different colony colours (greyish yellow and moderate orange), designated J-MR2-Y(T) and J-MR2-O, were isolated from a tidal flat in the South Sea of South Korea. The two novel strains grew optimally at 35-37 °C. Strains J-MR2-Y(T) and J-MR2-O showed no difference in their 16S rRNA gene sequences, and the mean DNA-DNA relatedness between them was 94%. Phylogenetic trees based on 16S rRNA gene sequences revealed that strains J-MR2-Y(T) and J-MR2-O clustered consistently with the type strains of Loktanella soesokkakensis, L. hongkongensis and L. cinnabarina, with which it exhibited 97.83-99.06% sequence similarity. Sequence similarities to the type strains of the other recognized species of the genus Loktanella were 94.01-96.26%. Both strains contained Q-10 as the predominant ubiquinone, C(18 : 1)ω7c as the major fatty acid and phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified glycolipid and one unidentified aminolipid as the major polar lipids. The DNA G+C contents of strains J-MR2-Y(T) and J-MR2-O were 68.1 and 68.4 mol%, respectively, and DNA-DNA relatedness values with the type strains of L. soesokkakensis, L. hongkongensis and L. cinnabarina were 19-37%. Differential phenotypic properties, together with their phylogenetic and genetic distinctiveness, revealed that the two novel strains are separated from other species of the genus Loktanella. On the basis of the data presented, strains J-MR2-Y(T) and J-MR2-O are proposed to represent a novel species of the genus Loktanella, for which the name Loktanella variabilis sp. nov. is proposed. The type strain is J-MR2-Y(T) ( = KCTC 42074(T) = CECT 8572(T)).

Synthesis and photoluminescence enhancement of PVA capped Mn2+ doped ZnS nanoparticles and observation of tunable dual emission: A new approach

This paper reports the enhanced photoluminescence (PL) property of polyvinyl alcohol (PVA) capped Mn2+ doped ZnS nanocrystals prepared by chemical precipitation method. The surface-modified Mn2+ doped ZnS nanocrystals resulted in the multi-color property. The morphology and crystallite size were characterized by field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) techniques. The crystallite size was estimated to be 5nm from HRTEM and calculated as 2–4nm from peak broadening of the X-ray diffraction (XRD) pattern with cubic zincblende structure. Increase in the band gap with decrease in the crystallite size was observed from the UV–visible absorption spectrum, which confirms the quantum confinement effect. The room temperature photoluminescence (PL) emission measurements revealed the presence of blue (427nm) and near IR reddish–orange (752nm) emission bands in addition to the typical yellow–orange (585nm) bands in all the Mn2+ doped samples, which were attributed due to transition within the 3ds configuration of Mn2+ ions incorporation in ZnS host under UV excitation at 320nm. As far as we know, the reddish–orange bands at 752nm near IR region along with the blue and yellow–orange colored PL are reported for the first time. In this way, the PL color from these ZnS nanocrystals can be tuned from UV to near infrared region (IR). The synthesized ZnS:Mn NPs can be further functionalized for using them as biolabels.

KOKINOSITE, Na2Ca2(V10O28)*24H2O, A NEW DECAVANADATE MINERAL SPECIES FROM THE ST. JUDE MINE, COLORADO: CRYSTAL STRUCTURE AND DESCRIPTIVE MINERALOGY

Kokinosite, Na2Ca2(V 10O28)•24H2O, is a new mineral species from the St. Jude mine, Slick Rock district, San Miguel County, Colorado, USA. Kokinosite typically occurs as tablets or blades up to 0.05 mm thick, with stepped faces, and 1 mm in maximum dimension. Crystals are yellow orange, although sometimes they are tinted orange brown; the streak of the phase is yellow. The luster of kokinosite is subadamantine, and the mineral is transparent; it does not fluoresce in short- or long-wave radiation. The Mohs hardness is ca . 1½. Kokinosite possesses a brittle tenacity, and displays one good cleavage on {01 ![Formula][1] }. No parting was observed, and fracture is irregular. Density (calc.) = 2.353 g cm−3 on the basis of the empirical formula and the single-crystal cell data. Kokinosite is biaxial (−), with α 1.725(3), β 1.770(5), and γ 1.785(3). The 2 V was measured as 56.6(3)° from extinction data, and 2 V calc = 58.7°. Dispersion is r , with a 8.74899(19), b 10.9746(3), c 12.8216(9)A, α 114.492(8), β 105.093(7), γ 91.111(6)°, V 1070.25(11) A3, and Z = 1. The strongest four lines in the diffraction pattern are [ d in A(I)( hkl )]: 9.88(100)(010,0 ![Formula][3] 1), 7.92(36)( ![Formula][4] 01), 8.42(33)(100), and 6.01(31)(1 ![Formula][5] 1,110). The atomic arrangement of kokinosite was solved and refined to R 1 = 0.0379 for 3806 F o > 4σ F reflections. The structural unit is a decavanadate polyanion, (V10O28)6−; charge balance in the structure is maintained by the [Na2Ca2(H2O)24]6+ interstitial unit that exists as Na(H2O)6 octahedra and Ca(H2O)8 polyhedra that link into chains by edge- and corner-sharing. The linkage between the structural unit and the interstitial unit occurs solely by hydrogen bonding. The new mineral is named in honor of Michael Kokinos (b. 1927) of Shingle Springs, California, a well-known mineral collector and member of the Micromounters’ Hall of Fame. [1]: /embed/mml-math-1.gif [2]: /embed/mml-math-2.gif [3]: /embed/mml-math-3.gif [4]: /embed/mml-math-4.gif [5]: /embed/mml-math-5.gif

Thermoflavifilum aggregans gen. nov., sp. nov., a thermophilic and slightly halophilic filamentous bacterium from the phylum Bacteroidetes

A strictly aerobic, thermophilic, moderately acidophilic, non-spore-forming bacterium, strain P373(T), was isolated from geothermally heated soil at Waikite, New Zealand. Cells were filamentous rods, 0.2-0.4 µm in diameter and grew in chains up to 80 µm in length. On the basis of 16S rRNA gene sequence similarity, strain P373(T) was shown to belong to the family Chitinophagaceae (class Sphingobacteriia) of the phylum Bacteroidetes, with the most closely related cultivated strain, Chitinophaga pinensis UQM 2034(T), having 87.6 % sequence similarity. Cells stained Gram-negative, and were catalase- and oxidase-positive. The major fatty acids were i-15 : 0 (10.8 %), i-17 : 0 (24.5 %) and i-17 : 0 3-OH (35.2 %). Primary lipids were phosphatidylethanolamine, two unidentified aminolipids and three other unidentified polar lipids. The presence of sulfonolipids (N-acyl-capnines) was observed in the total lipid extract by mass spectrometry. The G+C content of the genomic DNA was 47.3 mol% and the primary respiratory quinone was MK-7. Strain P373(T) grew at 35-63 °C with an optimum temperature of 60 °C, and at pH 5.5-8.7 with an optimum growth pH of 7.3-7.4. NaCl tolerance was up to 5 % (w/v) with an optimum of 0.1-0.25 % (w/v). Cell colonies were non-translucent and pigmented vivid yellow-orange. Cells displayed an oxidative chemoheterotrophic metabolism. The distinct phylogenetic position and the phenotypic characteristics separate strain P373(T) from all other members of the phylum Bacteroidetes and indicate that it represents a novel species in a new genus, for which the name Thermoflavifilum aggregans gen. nov., sp. nov. is proposed. The type strain of the type species is P373(T) ( = ICMP 20041(T) = DSM 27268(T)).

Color of Corn Grains and Carotenoid Profile of Importance for Human Health

The increasing on the levels of carotenoids in staple foods of broad human consumption is one of the strategies of food biofortification programs, mainly due to the importance of these compounds to human health on the prevention of vitamin A deficiency. Maize is a major staple food due to its high consumption in regions where problems of Vitamin A deficiency are of great relevance. Maize biofortification programs have made progress in determining the amounts of carotenoids in grain of thousands of accesses. This work aimed at studying the influence of the color of the grains in the profile of carotenoids in four different Brazilian genotypes. The selection of ears within the same genotype was based on a color scale, considering the lighter (lightest yellow) in one group and the most colorful (darkest orange) in another group. Significant interactions (p 0.05) between the color of the grains and the genotypes for all the variables were detected in addition to genetic variability for both groups (lightest yellow and darkest orange). The colored ears of corn showed a high level of total carotenoids (TC) and fractions in RS 535 and RS 445, and the colorful ears of genotype RS 535 showed 300% more α + β carotenes (μg·g-1) in relation to lighter of this same material. The results of this study showed the influence of genotype on the grain color and content of carotenoids, indicating that breeders have the flexibility to make selection of some genotypes based on grain color, reducing cost and time compared to laboratory methods used for the screening of genetic materials.

The nature of collagen in oral submucous fibrosis: A systematic review of the literature

Background: The nature of collagen in the oral potentially malignant disorder of oral submucous fibrosis (OSF) has always been a subject of interest to researchers studying the condition. The type, constitution, and morphology of the collagen has been studied to understand the pathogenesis of the disorder. Aim: The present review attempts to collate literature to assess the changes reported on the nature of collagen in OSF. Materials and Methods: A systematic analysis of literature based on the PRISMA protocol was carried out on studies that analyzed the nature of collagen in OSF. A total of 30 articles were found acceptable for analysis. The reported literature was categorized into histological, immuno-histochemistry (IHC), electron microscopic (EM)/scanning electron microscopic (SEM), biochemical, culture, and genetic studies. Results: Light microscopic studies revealed increased collagen with compaction and condensation as the disease advanced. Polarising microscopy revealed presence of greenish yellow (type I) thick fibers replacing the yellowish orange (type III) thin fibers in the submucosa. Fibrosis originated in the submucosa and subsequently involved the lamina propria as the disease advanced. EM/SEM investigations revealed frayed ends, degeneration of collagen cores. Increased expression of collagen antibodies and total collagen content were observed in IHC and biochemical studies, respectively. Cultured fibroblasts from OSF tend to produce more collagen in comparison to normal fibroblasts indicating a phenotypic change. Increased expression and upregulation of collagen genes were consistent in OSF cases. Conclusion: The collagen deposition in OSF is biochemically normal but quantitatively more. Fibroblast phenotypic change, upregulation of collagen genes, and selective remodeling due to decreased degradation seem to contribute to the increased fibrosis in the disorder.