Black Dots Research Articles

Point-defect engineering on phosphorene quantum dots for DNA bases adsorption and sensor performance

We have performed density functional theory (DFT) calculations to understand the interaction of DNA bases with pristine and point-defective black phosphorus quantum dots (BPQDs). The point-defect BPQDs show improved affinity for guanine molecule, and therefore are beneficial for guanine adsorption. More interestingly, the point defects in BPQDs can enhance the sensitivity to some extent for guanine, because the significant energy gap changes have occurred after the adsorption. The orbital hybridization near the Fermi energy level leads to significant energy gap changes in the point-defect BPQDs. Electron density topological analyses indicate that the electrostatic interactions play an important role in the stabilizing between base molecules and substrates. • DNA bases can be adsorbed on SV and DV BPQDs through physisorption state. • The electronic structures of SV and DV BPQDs are significantly altered upon guanine adsorption. • The electrostatic interactions were revealed by QTAIM and IGM. • The orbital interaction between guanine and defect BPQDs is significant.

FORCED ANALYSIS POCESS OF REED ROLL THREAD FOR SPARK PLUG

Spark plug is component or device of internal combustion engine (ICE) for make a compression and transfer energy to vehicle. Component of spark plug is center electrode, gasket, hexagon, insulator, corrugation, and terminal nut, the all component will assembly for internal combustion engine component. Thread is a critical component for connection spark plug and engine. the key of perfect thread is reed roll process when the motor makes a shell of part, the forced and rpm should be stable and do not over force for eliminate failure part. This study will discuss of forced analysis on thread and structure analyze from material spark plug after process. The result show in this case useing 2000 rpm and force 197,8N. Based on spot test material after threading, no any crack finding, only black dot due processing. Tortion test after assemblu 5 Kgf, for the lowest sample 1 is 8 Kgf, middle is sample 2 is 12 Kgf, and the bigger is 13 Kgf for sampling test. Igintion on sprak plug are normaly for ignition voltage lower is 13,3 kV, middle 15,3 kV, high 17,5 kV, and average is 15,3kV.

Arginine-modified black phosphorus quantum dots with dual excited states for enhanced electrochemiluminescence in bioanalysis

The electrochemiluminescence (ECL) is generally emitted via radiative transition of singlet or triplet excited state (S1 or T1). Herein, an ECL mechanism with the transitions of both S1 and T1 of black phosphorus quantum dots (BPQDs) is found, and an arginine (Arg) modification strategy is proposed to passivate the surface oxidation defects of BPQDs, which could modulate the excited states for enhancing the ECL efficiency of BPQDs. The Arg modification leads to greater spatial overlap of highest and lowest occupied molecular orbitals, and spectral shift of radiative transitions, and improves the stability of anion radical of BPQDs. To verify the application of the proposed mechanism, it is used to construct a sensitive method for conveniently evaluating the inhibiting efficiency of cyclo-arginine-glycine-aspartic acid-d-tyrosine-lysine to cell surface integrin by using Arg containing peptide modified BPQDs as signal tag. The dual excited states mediated ECL emitters provide a paradigm for adjustable ECL generation and extend the application of ECL analysis.

Tricoscopia en la alopecia areata: descripción de 10 casos

IntroductionAlopecia areata is a non-scarring alopecia of the autoimmune type characterized by an abrupt arrest of the follicular cycle, which can affect any hairy area. The diagnosis is clinical and trichoscopic, the latter with a fundamental role not only in diagnosing the disease, but also in determining its evolutionary stage, assessing signs of activity, remission, or chronicity, which makes it a fundamental tool in follow-up of our patients. Materials and methodsThe study includes 10 patients diagnosed with alopecia areata (AA) based on clinical history, physical examination, and trichoscopic findings. All trichoscopic images were obtained using a x10 magnification handheld dermatoscope (DermLite DL4) and an attached cell phone that increased magnification to x15 (Iphone 12, apple). They were reviewed retrospectively, the elements identified in each case were highlighted and a descriptive statistical analysis was performed. ResultsThe following elements were observed: black dots (80%), yellow dots (60%), exclamation mark hair (60%), broken hairs (60%), pigtail or circular hairs (40%), gray hairs (40%), repopulation straight hairs (30%), tapered hairs (10%), Pohl-Pinkus constrictions (10%), and white dots (10%). ConclusionsBlack dots, exclamation mark hairs, and yellow dots were the most frequent findings in our series. Blackheads, broken hairs, and exclamation point hairs were positively correlated with active disease.

Hylotelephium maximum from Coastal Drift Lines Is a Promising Zn and Mn Accumulator with a High Tolerance against Biogenous Heavy Metals

Heavy metal tolerance and accumulation potential are the two characteristics most important for plant use in phytoremediation technologies. Therefore, the aim of the present study was to characterize the tolerance of Hylotelephium maximum from coastal drift line vegetation against the biogenous heavy metals Cu, Zn, and Mn and its metal accumulation potential in controlled conditions. Plants were propagated vegetatively and cultivated in an automated greenhouse in a vegetative state (Experiment 1; Cu, Zn, and Mn) and in flowering-inducing conditions (Experiment 2; Mn gradient). In Experiment 1, total shoot biomass was negatively affected only by Mn at 1.0 g L−1, but root growth was significantly inhibited by all metals at this concentration. Plants accumulated 250 mg kg−1 Cu, 3200 mg kg−1 Zn, and >11,000 mg kg Mn−1 in their leaves. In Experiment 2, only new shoot growth was significantly suppressed at 0.5 g L−1 Mn. At the highest concentrations, shoot biomass progressively declined at the level of inhibition of flower and stem growth. Visual toxicity symptoms of Mn appeared 2 weeks after full treatment on leaves of 2.0 g L−1 treated plants as black dots along the main veins and spread over the leaf surface with time. The maximum Mn accumulation capacity was reached in leaves (15,000 mg kg−1), together with a high translocation factor and bioconcentration factor. The obtained results suggest that the particular accession of H. maximum has very good potential for practical phytoremediation purposes.

Elucidating the Effectiveness of Antibiotic Treatments in Eliminating the Black Dots Contamination from Vero Cell Line Culture

The present study was conducted to identify the effectiveness of various antibiotics and antibiotic combinations in eliminating the black dots contamination in cell culture and to identify its effect on cell growth kinetics. Isolation of contaminant organism (Black dots) observed in our laboratory, was attempted by inoculation of harvested cell supernatant and pellet into Nutrient broth, Luria broth, and Pleuropneumonia-like organisms’ broth but no visible growth was observed. To analyze the effect of antibiotics in elimination of contamination, the cell monolayer was incubated with different antibiotics and combination of antibiotics till 120 hrs. Withdrawal effect of antibiotics was observed by further incubation cells in maintenance media for another 48 hrs. To investigate the effect of different antibiotics on cell growth kinetics, cell seeding was done in media containing antibiotics. A subset of cells was harvested every 24 hrs and counted till 120 hrs. Among all antibiotics, Ampicillin reduced the contamination, the Piperacillin and Tazobactam combination diminished the contamination to a great extent. At the studied concentrations of the antibiotic trio of piperacillin, tazobactam, and ampicillin, black dot contamination was eliminated and found 100% effective in inhibiting contamination within 120 hrs of the study period; but, after 48 hrs of antibiotic withdrawal, contamination reappears in cell culture. The growth kinetics showed no significant impact of antibiotics treatment on the cell growth curve. The growth kinetics showed that cell growth was not interfering significantly by individual or combination of antibiotics. Therefore, in the presence of black dot, a combination of three antibiotics (piperacillin, tazobactam, and ampicillin) should be effective in cell culture.

Black phosphorus quantum dots: Nonlinear optical modulation material with ultraviolet saturable absorption

Black phosphorus has attracted great interest for optical modulation and optoelectronic devices because of its ultrathin layer structure, tunable band gap, and high in-plane anisotropy. In particular, in the near-infrared and mid-infrared bands, proof-of-concept applications, including saturable absorber resonators, photodetectors, and optical modulators based on 2D black phosphorus nanosheets, have been reported one after another. However, relatively few studies about black phosphorus have been reported in the ultraviolet band. Moreover, the poor stability of black phosphorus has also limited its development in practical applications. Here, we successfully prepared ultra-small black phosphorus quantum dots (BPQDs) with an average thickness of 2.0 ± 0.4 nm and a diameter of 2.2 ± 0.6 nm. Furthermore, we also fabricated BPQD-Ormosil gel glasses. Through an open-aperture Z-scan experiment, BPQD-Ormosil gel glasses demonstrated excellent nonlinear optical modulation in the ultraviolet band, which proposes a new idea for ultraviolet optical modulation elements such as saturable absorption devices.

En1 and Lmx1b do not recapitulate embryonic dorsal-ventral limb patterning functions during mouse digit tip regeneration.

The mouse digit tip regenerates following amputation. How the regenerate is patterned is unknown, but a long-standing hypothesis proposes developmental patterning mechanisms are re-used during regeneration. The digit tip bone exhibits dorsal-ventral (DV) polarity, so we focus on En1 and Lmx1b, two factors necessary for DV patterning during limb development. We investigate whether they are re-expressed during regeneration in a developmental-like pattern and whether they direct DV morphology of the regenerate. We find that both En1 and Lmx1b are expressed in the regenerating digit tip epithelium and mesenchyme, respectively, but without DV polarity. Conditional genetics and quantitative analysis of digit tip bone morphology determine that genetic deletion of En1 or Lmx1b in adult digit tip regeneration modestly reduces bone regeneration but does not affect DV patterning. Collectively, our data suggest that, while En1 and Lmx1b are re-expressed during mouse digit tip regeneration, they do not define the DV axis during regeneration.

Transepidermal Delivery of Triamcinolone Acetonide or Platelet Rich Plasma Using Either Fractional Carbon Dioxide Laser or Micro-needling in Treatment of Alopecia Areata.

Trans-epidermal drug delivery, using "laser-assisted drug delivery", or micro-needling, are new treatment modalities, that can improve drug penetration into skin in treatment of alopecia areata patients. To evaluate the use of fractional carbon dioxide laser versus micro-needling in trans-epidermal delivery of triamcinolone acetonide and platelet rich plasma in alopecia areata treatment. Interventional comparative study carried out on 60 patients, randomly divided into four equal groups. Group I: Fractional Carbon dioxide laser and triamcinolone acetonide. Group II: micro-needling with Dermapen and triamcinolone acetonide. Group III: fractional carbon dioxide laser and platelet-rich plasma. Group IV: micro-needling with Dermapen and platelet-rich plasma. Patients were evaluated clinically, using Severity of Alopecia Tool score and hair regrowth scale, and dermoscopically. In all treatment groups, there was improvement in the Regrowth scale, with statistical significance between the different groups at fourth (P = 0.001) and last (P = 0.008) visits, with highest, most significant changes in Pen-Steroid group. Comparing Regrowth scale at last visit, results were in favor of Dermapen, compared to Carbon dioxide laser for trans-epidermal drug delivery (P = 0.023); and in favor of triamcinolone acetonide, compared to platelet-rich plasma as topical medication (P = 0.015). Dermoscopic signs of improvement included decrease in black dots, and appearance of Upright regrowing hairs (P < 0.001). Micro-needling and fractional carbon dioxide laser are effective tools for trans-epidermal drug delivery for Alopecia areata treatment. Micro-needling for delivery of Triamcinolone acetonide showed best treatment outcomes. Dermoscopy is highly beneficial in evaluating treatment response in alopecia areata.

The joy of connecting quantum black dots

The joy of connecting quantum black dots

Clinical cases of Darier-White follicular dyskeratosis

Follicular dyskeratosis (Darier-White disease) is a hereditary skin disease that is extremely rare in medical practice, so errors in its diagnosis can occur. It was first described in 1889 by two scientists (independently of each other), Ferdinand-Jean Darier and James White. The disease is inherited in an autosomal dominant pattern with variable gene penetrance. The main cause of this pathological process is a mutation of the ATP2A2 gene, located in the long arm of chromosome 12. Both men and women are affected with the same probability, but clinical manifestations are more severe in males. It appears, as a rule, at the age of 20; children under 10 rarely suffer from DAR; people who are over 30 years have very little chance of contracting this disease. Clinical manifestations slowly progress up to the age of 40-50, and gradually disappear in older age. Typical rashes are follicular papules, 0.2-0.5 cm in size, yellow-brown or dark brown in color, covered with dry or oily layers in the form of horny scales. On the surface layers, black dots are visible which are hair follicle funnels. Papules are rounded, dense, flat or spherical, initially isolated, eventually merging into plaques. They are mostly localized on the skin of the limbs, trunk, chest, in the interscapular area, large folds, less often on the neck, scalp, auricles, and in the ear canals. In 20-30 percent of patients, rashes are localized on the mucous membrane of the oral cavity next to the affected skin. More than 90 percent of patients have nail abnormalities, such as erythro- and leukonychia. Other possible manifestations are fragility, splinter hemor­rhages, marked subungual hyperkeratosis, which can be observed on 2-3 nails or affect all nail plates. The dermatoscopy of skin lesions is characterized by the presence of several polygonal, branched, star-shaped or rounded-oval yellow-orange-brown lumps of various sizes, surrounded by a thin whitish halo and pink small-structured areas. The prognosis for recovery is not favorable, the treatment is ineffective. Two cases of Darier-White disease are described in this article.

Design and synthesis of black phosphorus quantum dot sensitized inverse opal TiO2 photonic crystal with outstanding photocatalytic activities

Quantum dot sensitized photocatalyst is designed and applied in purification of dye wastewater, using black phosphorus nanoparticles (BPQDs) as the quantum dot and inverse opal (IO) TiO2 photonic crystal as the main photocatalyst. Due to electron density change within the composite, electrons can transfer from BPQDs to IO TiO2 directionally. Bandgap energies and relative energy band positions of BPQDs and IO TiO2 further provide efficient electronic transmission channels at the heterojunction interface. Therefore, interfacial resistance for charge transfer is reduced, the production of active oxidative species is promoted, and the photo induced charge transfer proceeds through a typical type-II route. Finally, excellent photocatalytic properties of BPQDs-IO TiO2 are achieved with the highest apparent kinetic constant (kapp) of 0.046 min−1, which is more than 3 times for bare IO TiO2 (0.014 min−1) and nearly 2 times for commercial P25 TiO2 (0.027 min−1). Furthermore, long-term stability and non-toxicity make the quantum dot sensitized photocatalyst have great applications in purifying environmental water pollution.

Kinetics-favorable heterojunctional CNTs@CuCo-LDH/BPQD electrode with boosted charge storage capability for supercapacitor

Component modulation and structure construction are the fundamental strategies in designing electrode materials for supercapacitors. Layered double hydroxide (LDH) is considered the promising electrode material, while with the drawback of low electron transmission efficiency and pulverization hinder. Herein, a novel kinetics-favorable heterojunctional self-supporting film electrode, composed of carbon nanotubes (CNTs), CuCo-LDH, and black phosphorus quantum dots (BPQD), is successfully prepared and directly utilized as electrodes in the supercapacitor. Highly conductive CNTs evenly and heavily entangled with CuCo-LDH hollow structures, resulting in robust mechanical property, enhanced electrical conductivity, and accelerated charge transfer during a redox reaction. Together with the surface decorated high-carrier-mobility BPQD, constructing heterojunction and acting as an electron donor to provide numerous active sites and facilitate energy storage behavior, a promoted pseudocapacitive performance was obtained and furtherly demonstrated by the density functional theory simulations based on the adsorption energies of OH–. The as-fabricated CNTs@CuCo-LDH/BPQD electrode presents a maximum capacitance of 1061.6 F g−1. The as-assembled hybrid supercapacitor device represents energy density up to 62.1 Wh kg−1 and remarkable cycling performance with 79.1% capacity retention after 10,000 cyclic tests. The prototype supercapacitor of this work shed light on the engineering of LDH-based materials for practical energy storage devices.

Black phosphorus quantum dots cause glucose metabolism disorder and insulin resistance in mice

Black phosphorus quantum dots (BPQDs) are considered to have wide application prospects due to their excellent properties. However, there is no study on the effect of BPQDs on glucose metabolism. In this study, blood glucose was significantly increased when mice were continuously intragastrically administered 0.1 and 1 mg/kg bw BPQDs. The blood glucose level of the mice was elevated from Day 7 to Day 28. BPQD exposure also decreased the area under the curve (AUC) of the oral glucose tolerance test (OGTT). After exposure, the pancreas somatic index was increased. Moreover, the serum insulin and glucagon levels were elevated and the relative area of islet β cells was increased in BPQD-exposed mice, while insulin signaling cascades were reduced in muscle tissues. In summary, our study demonstrated for the first time that BPQD exposure induces glucose disorder and insulin resistance in muscle, which is helpful to understand the biosafety of black phosphorus nanomaterials and promote the sustainable development of nanotechnology.

Anagen effluvium due to azathioprine in a patient with normal thiopurine S-methyltransferase levels: A videodermoscopic analysis

Introduction: Anagen effluvium (AE) is caused by impaired mitotic activity of matrix cells in the hair follicles. It presents with sudden loss of hair and myelosuppression. The diagnosis is based on the clinical history, trichoscopy, and trichogram. We herein report a case in which videodermoscopy revealed new trichoscopic features of AE caused by azathioprine in a patient with normal thiopurine S-methyltransferase levels. Case presentation: A 20-year-old woman presented with sudden loss of hair following treatment with oral azathioprine. Evaluation of the thiopurine S-methyltransferase (TPMT) were within normal limits both in genotype and phenotype levels. Hair pull test was positive. Trichoscopy revealed yellow dots and multiple black dots, empty yellow dots, dark lines, upright regrowing hairs, and circle hairs. Azathioprine was stopped, and minoxidil 5% and oral multivitamin were started. Post-treatment trichoscopic analysis revealed terminal hairs and upright regrowing hairs Discussion: AE is characterized by abrupt loss of anagen hairs due to impaired metabolic activity. Trichoscopy in AE shows coudability hairs, black dots, exclamation mark hairs, multiple broken shafts, and regrowing hairs. Empty yellow dots, yellow dots with black dots, pigtail hairs, and dark lines were additional features in this study. Conclusion: Trichoscopy assists in the accurate diagnosis of AE. Adverse effects of azathioprine can be observed even with normal TPMT levels. Weekly monitoring is therefore of prime importance.

The effects of high energy deuteron ion beam irradiation on the tensile behavior of HT-9

Ion beam implantations are widely performed to understand the effects of irradiation-induced displacement damage on nuclear structural materials. However, the volume of material that can be investigated is often limited by the maximum energies of accelerator facilitates, leading to a limitation in the thickness of samples whose mechanical properties can be evaluated. The Lawrence Berkeley National Laboratory’s 88-Inch Cyclotron offers a wide range of ions and energies, allowing for material ion implantations at larger scales than typical. Four HT-9 SS-J-geometry tensile specimens were polished and then irradiated with deuterons at the 88-Inch Cyclotron to doses of approximately 0.2 dpa prior to small scale tensile testing. The results from this study show irradiation hardening characterized by the tensile test results and black dot irradiation defects. Additionally, a comprehensive look at low temperature irradiations of high-Cr F/M steels is presented and our results show agreement with the available data.

Left atrial volume, function and B-lines at rest and during vasodilator stress echocardiography

Abstract Background Left atrial volume index (LAVi), left atrial reservoir function assessed with global peak amplitude longitudinal strain (PALS), and B-lines at lung ultrasound are supplementary markers of left ventricular filling pressures. Aim To assess the relationship between LAVi, PALS and B-lines at rest and peak vasodilator stress. Methods A comprehensive dipyridamole stress echo was completed in 266 patients (187 male, 71%, age 65±10 years) with chronic coronary syndromes. LAVi was measured with the biplane disk summation method. PALS was measured from a single vendor with 2-dimensional speckle tracking echocardiography and expressed in % values as the mean of the 12 atrial segments from 4- and 2-chamber values. B-lines were assessed with the simplified 4-site scan in the third intercostal space, with global score from 0 to 40, and considered significant with global score ≥2 units. Results During dipyridamole, LAVi decreased (rest= 26±14 ml/m2 vs stress= 24±12 ml/m2, p&amp;lt;0.001), PALS increased (rest= 33±8 vs stress= 38±10%, p&amp;lt;0.001), and B-lines were more frequent (rest= 0.4, median interquartile range 0–30, vs stress= 0.7, median interquartile range 0–30, units, p&amp;lt;0.001). There was a significant, linear, inverse correlation between LAVi and PALS both at rest (r=−0.301, p&amp;lt;0.001) and at peak stress (r=−0.279, p&amp;lt;0.001, see figure). At group analysis, peak B-lines were directly correlated with peak LAVi (r=0.151, p=0.017) and inversely correlated with peak PALS (r=−0.234, p&amp;lt;0.001). At individual patient analysis, 4/93 patients (4.3%) showed stress B-lines (black dots in figure) with normal LAVi (&amp;lt;34 ml/m2) and preserved PALS (&amp;gt;42%). Conclusion Vasodilator stress echocardiography with combined assessment of left atrial volume, function and pulmonary congestion is feasible with high success rate in patients with chronic coronary syndromes. Pulmonary congestion is more frequent with dilated left atrium with reduced atrial contractile reserve, but it may occur in a minority of patients with normal LAVi and normal PALS. Funding Acknowledgement Type of funding sources: None.

Colletotrichum coccodes causing “black dot” of sugar beet in the Pacific Northwest of the USA

Sugar beet (Beta vulgaris) is an important sugar crop in temperate regions. In 2014, sugar beet roots in Washington and Oregon, U.S.A. were found with a shallow, firm, dark rot with minute black “dots” within the tissue (Figs. 1, 2), similar to “black dot” on potato (Davis & Johnson, 2001). Symptoms were observed in freshly harvested roots in the processing factory. Diseased tissue was surface disinfected with 10% bleach, plated on 2% water agar and incubated at room temperature with ambient lighting. All visible growth from ten tissue pieces (five per beet, one each from Washington and Oregon) was fungal, with hyaline mycelia and numerous dark, spherical sclerotia. Pure cultures were obtained by hyphal tip transfer to malt extract agar (MEA), incubated for seven days in the light at room temperature, and examined for morphological characteristics. Yellow spore clusters with dark setae were observed in culture. Conidia (20-25 × 3–4 µm) were hyaline and straight with evenly rounded ends (Fig. 3) matching those of Colletotrichum coccodes (Chesters & Hornby, 1965). For molecular characterisation, DNA was extracted from seven-day old cultures using a CTAB protocol (Anonymous, 2009). PCR amplification used an Invitrogen High Fidelity PCR mix (Thermo Fisher Scientific Inc., Waltham, USA) with primers ITS1 and ITS4 (White et al., 1990) and the resulting amplicons were sequenced by Sanger sequencing. A BLASTn search with the sequence of isolate Co14-1 (GenBank Accession No. KX011522) showed a 99% identity to CBS369.75 (HM171679), the type strain for C. coccodes (Cannon et al., 2012) as well as to additional C. coccodes isolates (JX294043, JX205194, JX205192, and KJ744346). As initial samples were found at harvest, healthy roots of two sugar beet germplasm (C869 and SR102) that had been grown in the field for five months at the Saginaw Valley Research and Education Center (Frankenmuth, Michigan, USA) were used for pathogenicity testing. After removal from the field, roots were kept at 7°C for one-two months then planted in potting mix and grown in a greenhouse at 22°C ±4°C. After growth of new leaves was visible, two plants of each germplasm were treated with a 10 ml drench of a 103 spores/ml suspension that was produced by growing isolate Co14-1 on MEA for seven-ten days, flooding the surface with sterile distilled water, and dislodging the spores with a sterile plastic cell spreader. Plants were grown for four weeks after inoculation and evaluated. Roots of inoculated plants showed shallow sunken lesions with minute black “dots” similar to those on the initial samples (Fig. 4). A fungus morphologically identified as C. coccodes was isolated from lesions on all inoculated beets, completing Koch's postulates. No Colletotrichum sp. was isolated from control beets. The trial was conducted twice with the same results. To our knowledge this is the first report of C. coccodes on sugar beet from the field. Although there was little root loss observed on beet, black dot infection can impact storage in potato (Davis & Johnson 2001). Therefore, testing the potential impact of black dot on storage of sugar beet is warranted. The authors would like to thank Tom Goodwill for his technical assistance.

Clinico-mycological profile and trichoscopic findings among pediatric tinea capitis patients: A cross-sectional study from northern India (Haryana)

Background: Tinea capitis (TC) is the most common cause of hair loss in pediatric patients leading to varied manifestations. Essentially, TC is a superficial infection which affects hair shaft, hair follicle, and the scalp. Aims and Objectives: The aims of this study were to describe the clinic-mycological characteristics and trichoscopic findings of TC among pediatric patients. Materials and Methods: This cross-sectional study was undertaken in Shaheed Hasan Khan Mewati, Government Medical College and Hospital after obtaining approval from the Institutional Ethics Committee. All the pediatric patients of TC enrolled during the study period of 1.5 year (between January, 2020 and June, 2021). Trichoscopy was performed and findings were recorded on a predesigned pro forma. All participants were clinically examined and sample of hair and scalp scrapping was taken for mycological investigation (potassium hydroxide [KOH] and Sabouraud Dextrose Agar culture). Results: Among 100 children of TC (M/F=2.2), gray patch type TC was most common, whereas pustular variant was least common. Trichoscopic findings were seen in all 100 cases with short broken hair being most common. Perifollicular scaling was statistically significant in gray patch TC, black dot, and comma shape in black dot TC and, crock screw hair and thick crust in kerion TC. By combining perifollicular scaling, comma hair, short-broken hair, black dot, and erythema, a sensitivity of 98.8% was achieved. KOH revealed fungal spore/hyphae in 79% patients with ectothrix pattern (56.9%) more commonly than endothrix pattern (34.2%). Trichophyton violaceum (25.9%) was the most common species isolated among culture positive patients. Conclusion: Trichoscopy could be a simple, valuable, non-invasive, rapid, and easy to perform method for diagnosing tinea capitis in resource poor settings, where mycological culture facility is not available and in situations where delay in treatment can be counterproductive.

Fabrication of black phosphorous quantum dots and Ag nanoparticles co-sensitized TiO2 nanorod arrays as powerful SERS substrate

Surface enhanced Raman scattering (SERS) substrate based on plasma metal nanoparticles and non-metal quantum dots co-sensitized semiconductor has been used in limit trace detection test. In this research, BPQDs (black phosphorus quantum dots) and Ag nanoparticles co-sensitized TiO 2 nanorod arrays were successfully fabricated as powerful SERS substrate. For BPQDs/Ag/TiO 2 , its detection limit of 4-mercaptobenzoic acid (4-MBA) molecules could achieve even at as low as 1.0 × 10 −12 M, and the enhancement factor (EF) is up to 2.5 × 10 5 , exhibiting an excellent SERS sensitivity. Furthermore, a good uniformity is also observed during the detection process, the relative standard deviation of 4-MBA Raman fingerprint peak intensity at 1587 cm −1 is only 7.3 %. Furthermore, BPQDs/Ag/TiO 2 substrate is demonstrated to have good repeatability and stability. The synergistic effect of BPQDs, Ag nanoparticles and TiO 2 nanorod array is mainly responsible for improved SERS activity, namely, high-density hot spot, optical capture expansion and enhanced charge transfer. • BPQDs/Ag/TiO 2 was firstly fabricated as powerful SERS substrate. • SERS detection limit of BPQDs/Ag/TiO 2 substrate toward 4-MBA could achieve 1.0 × 10 −12 M. • The study provides an efficient approach to extend the photocarriers lifetime of BPQDs. • The possible electron generation and transport modes of BPQDs/Ag/TiO 2 was investigated.