Black Dots Research Articles

Ultrasmall Black Phosphorus Quantum Dots with Robust Antioxidative Properties for Acute Kidney and Liver Injury Therapy.

Acute organ injuries, such as acute kidney injury (AKI) and acute liver injury (ALI), usually present high morbidity and mortality in patients. However, the current clinical treatments remain limited, especially the lack of effective drug-based treatment. Since these acute injuries are often associated with reactive oxygen species (ROS) overproduction, it is a promising strategy to develop therapeutic agents with potent ROS scavenging ability and excellent biocompatibility for efficient antioxidation therapy. Black phosphorus quantum dots (BPQDs), low-dimensional nanomaterials prepared through a straightforward one-step method and capable of complete controllable biodegradation, offer significant potential. This study comprehensively explores the extensive free-radical scavenging capabilities of BPQDs, underscoring their immense potential in treating ROS-related organ injuries. BPQDs could simultaneously achieve radical scavenging of DPPH, ABTS·, OH·, and O2 -· and exhibit excellent cytoprotective effects against ROS-mediated damage even at extremely low dosages. Besides, the ultrasmall size of BPQDs (≈3-5nm) allows them to effectively penetrate the glomerular filtration barrier (≈6nm), significantly improving the symptoms of AKI and ALI in vivo. The therapeutic efficacy and great biocompatibility of BPQDs facilitate the clinical management of ROS-related diseases, which will broaden the applications of QDs in the field of biomedicine.

Effects of Cold Rolling–Induced Defects on Proton Irradiation Response in Nb-1Zr-0.1C Alloy

This work highlights the effect of proton irradiation in the presence of preexisting defects in the Nb-1Zr-0.1C alloy. To introduce the initial defects, the Nb-1Zr-0.1C alloy was subjected to cold rolling (10% and 20%) prior to irradiation. Characterization of the irradiated material was performed using detailed X-ray diffraction line profile analyses. The results, in terms of various microstructural parameters, revealed that the preexisting defects in these materials act as effective sinks for irradiation-induced defects during the initial irradiation. Electron backscattered diffraction analyses suggested that the fraction of low-angle grain boundaries plays a crucial role during irradiation and determines the outcome of the competing process between defect annihilation and defect production. Transmission electron microscopy analyses revealed that the black dots were coexisting with carbide precipitate in the cold-rolled Nb alloy after irradiation. Mechanical properties were also assessed by measuring microhardness to correlate with the changes in microstructure after irradiation. The change in yield strength calculated from the change in the microhardness value as a function of dose indicated that the 20% cold-rolled Nb alloy was more radiation resistant than the 10% cold-rolled Nb alloy at ambient temperature and a low-dose regime. To see the effect of alloying elements, similar studies were also carried out on pure Nb, and the results were compared with that of the Nb-1Zr-0.1C alloy. All these findings help to develop a better understanding of the behavior of the proton-irradiated Nb-1Zr-0.1C alloy in the presence of preexisting defects introduced by means of cold rolling prior to irradiation.

Electrochemical reconfiguration of NiFe layered double hydroxide on BiVO4 induced by black phosphorus quantum dots for promoting photoelectrochemical water splitting

Electrochemical reconfiguration of NiFe layered double hydroxide on BiVO4 induced by black phosphorus quantum dots for promoting photoelectrochemical water splitting

Trichoscopic Evaluation of Focal Non-Cicatricial Alopecia in Egyptian Children

Introduction: Dermoscopy is a noninvasive diagnostic tool that allows the recognition of morphologic structures not visible to the naked eye. Trichoscopy is useful for the diagnosis and follow-up of hair and scalp disorders. Objective: The aim of the present study is to evaluate the causes of focal non-cicatricial alopecia in Egyptian children and to assess the importance of the trichoscope in the diagnosis of each disease. Methods: This study was done with 200 Egyptian children patients aged from 2 to 18 years who suffered from focal non-cicatricial alopecia. Clinical and dermoscopic evaluations were performed for all patients, and informed consent was obtained from their parents. Results: The most prevalent diagnoses were alopecia areata (42%) and tinea capitis (40.5%), followed by trichotillomania (8%) and tractional alopecia (7%). Congenital triangular alopecia (1.5%) and patchy androgenetic alopecia (1%) were less common. Trichoscopy revealed distinct features in alopecia areata cases, such as short vellus hair, exclamation mark hair, black dots, broken hair, pigtail hair and upright regrowing hair. The most common trichoscopic features of tinea capitis were comma hair, corkscrew hair, broken hair, bent hair, zigzag hair, morse code hair, perifollicular scaling, and diffuse scaling. These findings contribute to understanding the etiology and clinical presentation of childhood alopecia, facilitating accurate diagnosis and appropriate management. Conclusion: The routine use of dermoscopy in the clinical evaluation of scalp and hair disorders enhances diagnostic capabilities beyond simple clinical inspection. Dermoscopy reveals disease features that contribute to accurate diagnosis and improved management.

First Report of Alternaria alternata Causing Alternaria Leaf Spot of Black Nightshade in China.

Black nightshade (Solanum nigrum L.) belongs to Solanaceae family, which is distributed all over China and has become one of the malignant weeds in cotton field in Xinjiang (Zhang et al., 2020; Zhang et al., 2021). During July 2016 to August 2023, leaf spot was observed on black nightshade in Hami and Shihezi city, Xinjiang, China. The spots appeared as brown circular or irregular, with some small black dots surrounded with yellow halos. Twenty five black nightshade plants were collected from a cotton field (100 m2) for pathogen isolation in Shihezi, July 2023. Leaf samples (2×2 mm) from the boundary between diseased tissue and healthy tissue, sterilized in 70% ethanol for 45 s, dipped in 2% NaClO for 30 s, rinsed three times with sterile distilled water, placed on potato dextrose agar (PDA) after dried and cultivated at 25°C in the dark for 4 days. Twenty-five fungal isolates were obtained and purified by using the single-spore isolation method, and all isolates were found to be similar in morphology, appeared as dark brown and produced dark brown pigmentation on PDA. Conidiophores were black brown, 8 to 58 × 10 to 20 μm, with 1 to 5 transverse septa and 0 to 3 longitudinal septa, the results similar to those of Alternaria alternata isolated from buckwheat (Li et al., 2021). To confirm this identification, total genomic DNA of the isolates were extracted by CTAB method (Doyle et al., 1987). The internal transcribed spacer (rDNA-ITS), Alternaria major allergen gene (Alt α1) and glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH) of the A. alternata 26 were amplified using the primers ITS1/ITS4 (Glass et al., 1995), Altα1-F/Altα1-R (Li et al., 2024) and gpd-F/gpd-R (5'-CAACGGCTTCGGTCGCAT- TG-3' / 5'-GCCAAGCAGTTGGTTGTG-3'), respectively. The rDNA-ITS, Altα1 and GAPDH gene sequences were deposited in GenBank (KX904867, PP263361, PP263360), and showed 100% identity (rDNA-ITS: 572 out of 609 bp; Alt α1: 514 out of 516 bp; GAPDH: 619 out of 619 bp) to A. alternata (KU179665; MW522975; MK451977), respectively. The multi-gene phylogenetic tree showed that the representative isolate was grouped with A. alternata and identified as A. alternata. Black nightshade was used for pathogenicity assay. Fifteen plants at 3 to 4-leaf stage were selected and sprayed with the conidial suspension (1.0×106 spores/mL) of A. alternata 26 after wound the underside of leaves (2 mm length) with inoculating needle. Five plants were sprayed with sterilized water as control. After inoculation, placed the plants in a plastic box and covered with plastic wrap to keep 80% relative humidity for 3 days at 25℃ in the greenhouse, then removed the plastic box. Symptoms of leaf spots appeared within 12 - 15 days that were similar to the symptoms observed in the field, and the fungal pathogen that was re-isolated from symptomatic leaves was identical to original pathogen on the basis of morphological and molecular analysis to fulfill Koch's postulates. This experiment was repeated three times, and the disease incidence was above 80% after inoculation at each time. To our knowledge, this is the first report of A. alternata causing leaf spot of black nightshade in China. This report will help us to monitoring distribution of the disease and providing theoretical basis for disease prevention and control.

Naturalization and evaluation of synthetic random stripes pattern for digital image correlation

Abstract The morphology of speckle patterns commonly used in the Digital Image Correlation (DIC) community can be categorized into artificially generated free shapes and computer-synthesized circular dots. Due to the non-repeatability of manually sprayed patterns, researchers tend to favour code-controlled dot patterns, which exist in two forms: “white dots on a black background” and “black dots on a white background”. However, from the perspective of biological evolution, these two dot patterns can be hybridized “in silico” using the Turing model to create an intermediate form—the “striped-like” pattern. This hybridization significantly improves species identification and environmental adaptability. Although there have been reports on producing stripe patterns based on the kernel-based Turing model, there is no specific speckle pattern generation specification or comprehensive evaluation research for DIC applications. This paper naturalizes a novel striped speckle pattern and a corresponding generation approach. The pattern quality was assessed and compared with circular dots and hand-sprayed speckles. The stripes pattern outperformed the other two forms regarding Mean Intensity Gradient (MIG), q-factor, systematic bias, and random error. Sub-pixel displacement simulation and actual translation test results demonstrate that the proposed striped pattern offers higher precision and robustness in displacement and static strain measurements. Therefore, this striped pattern provides a preferred alternative for DIC technicians.

Deep Fungal Infections of Skin and Role of Histopathology in Diagnosis

Abstract Introduction: Deep mycoses acquired by penetrating trauma to the skin can have varied and sometimes atypical morphological presentations resulting in diagnostic dilemmas and delay in treatment onset. Histopathology can be a useful tool in not only diagnosing but also differentiating various deep mycoses. Aims and Objectives: To observe various morphological presentations and histopathological features of deep fungal infections. Materials and Methods: A retrospective multi-centric study was conducted from 2010 to 2020 at 16 centres. The cases with diagnoses of various deep mycoses were included in the study. The patients presenting with cutaneous manifestations were included in the study. Their demographic details, history, presenting signs and symptoms, morphological presentations, histopathological features and treatment details were collected from the case sheets. Results: A total of 124 cases were found from the case records. The most common type was chromoblastomycosis (42) followed by mycetoma (28) and rhinosporidiosis (17). The mean age was 43.76 ± 5.44 years. The average duration of symptoms before presentation was between 2 months to 10 years (average 2.5 ± 1.33 years). Male to female ratio was 1:0.7. Prior history of trauma was recorded in 36% of cases. Chromoblastomycosis cases presented with verrucous to atrophic plaques with black dots on the surface and histopathology findings included pesudoepitheliomatous hyperplasia, epithelioid cell granulomas, copper penny bodies within granulomas and abscesses. Rhinosporidiosis cases had polypoid grape-like lesions in the nose and eyes most commonly with histopathology findings of abundant thick-walled sporangia in dermis packed with thousands of spores. Eumycetoma patients had pigmented, indurated swelling with multiple sinuses discharging black granules and histopathology showed dermal abscesses and foreign body granulomatous reaction with PAS-positive hyphae. Histoplasmosis patients presented with few to multiple nodulo-pustular lesions on skin and palatal ulcers while small basophilic bodies packed in the cytoplasm of histiocytes were noted in histopathology. Phaeohyphomycosis cases presented as deep-seated cystic lesions and biopsy revealed deepithelialized cysts in the dermis or hypodermis with lumen showing necro inflammatory debris and fungal hyphae. Sporotrichosis cases had erythematous, tender nodules and papules either as single lesions or as multiple lesions arranged in a linear fashion and histopathology showed pseudoepitheliomatous hyperplasia of epidermis, loose to well-defined epithelioid cell granulomas and microabscesses. Spores were found in two cases. Cryptococcosis patient had multiple umbilicated lesions resembling giant molluscum contagiosum loose epithelioid cell granulomas and medium-sized spores lying in both intra and extracellularly on histopathology. Penicilliosis patients had nodulo-pustular lesions and histopathology showed an admixture of histiocytes, epithelioid cells, plasma cells, lymphocytes and polymorphs in the dermis with the presence of yeast-like spores in the cytoplasm of histiocytes and epithelioid cells. Entomophthoromycosis cases presented with asymptomatic subcutaneous firm swelling with loss of skin pinchability. Conclusion: Though clinical findings of deep fungal infections are characteristic similar morphology and atypical presentations can be sometimes confusing. Histopathology is useful for confirming the diagnosis.

Bacterial outer membrane vesicles-clothed nanoparticles delivered by live macrophages for potentiating antitumor photoimmunotherapy

Tumor-associated macrophage (TAM) plays an important role in tumor immune regulation. Reprogramming TAMs to reshape immunosuppressive tumor microenvironment (TME) is a promising antitumor strategy. Herein, imiquimod (R837) and black phosphorus quantum dots (BPQDs) are encapsulated in bacterial outer membrane vesicles (OMVs)-clothed liposomes to obtain RB@OL nanoparticles, which are further delivered by M1-type macrophages through phagocytic loading (RB-OL@M). Owing to the natural homing ability of macrophages to tumor sites, RB-OL@M actively targets cancerous region after intravenous injection. Meanwhile, upon laser irradiation, RB@OL is released from macrophages to exert combinational photoimmunotherapy due to the excellent phototherapeutic property of BPQDs and TAM regulating potential of R837. Benefiting from this versatile strategy, RB-OL@M effectively delays the growth of 4 T1 breast tumors and prevents the occurrence of their dreadful lung metastasis, largely prolonging the survival of 4 T1 tumor-bearing mice. Overall, this work offers a promising antitumor approach based on live cell-mediated multirole nanoplatform.

Zeolite-decorated black TiOx quantum dots for photocatalytic degradation of organic cationic dyes under LED light irradiation

Defect engineering is a promising strategy to reduce the band gap of semiconductors, enhancing their photocatalytic activity under visible light by introducing intra-bandgap energy states. Among the materials studied, oxygen-deficient black TiOx stands out due to its potential in photocatalytic reduction and hydrogen evolution. However, the valence band edge maximum (VBM) of TiOx is not thermodynamically favorable for the direct oxidation of water to hydroxyl radicals (H2O/•OH). Although the formation of extensive oxygen vacancies is necessary to extend the light absorption of black TiOx to longer wavelengths, a high density of oxygen vacancies (Ov) significantly shortens the diffusion length of charge carriers within the TiOx, leading to increased recombination of electrons and holes (e-/h+), thereby suppressing photocatalytic activity. To overcome these limitations, confining TiOx particles to the quantum dot (QD) size range and constructing heterojunctions with a secondary phase can substantially improve charge carrier separation and photocatalytic performance. In addition to engineering the electronic structure of composite photocatalysts, the preaccumulation of pollutants and their subsequent degradation is an effective strategy. This method decreases the distance between the adsorbed pollutant and the active sites for reactive oxygen species (ROSs) generation, enhancing the efficiency of the photocatalytic degradation process. In this study, we confined TiOx particles to the quantum dot size range by constructing a heterojunction with H-Beta zeolite, which contains defect-induced energy states within its wide band gap. This type of zeolite is particularly effective in adsorbing cationic azo dyes, facilitating pre-accumulation and degradation. The synthesized catalysts were extensively characterized using HRTEM to determine the average size of the TiOx particles and photoluminescence (PL) analysis to investigate charge carrier separation. Our results demonstrated that while TiOx alone showed negligible degradation efficiency, and no •OH were detected, the QD TiOx/Z4 composite achieved complete oxidation of CV by •OH, as confirmed by TOC analysis. The photocatalytic degradation mechanism was proposed based on these experimental findings. These insights could be of significant interest to researchers exploring defective semiconductors for photocatalytic oxidation of organic pollutants in the liquid phase under visible light (LED) irradiation.

Characterization of irradiation-induced dislocation loops in Vanadium at 25-500 °C

Vanadium-based alloys have emerged as promising candidates for structural materials in fusion applications. However, as its base metal, the response of V to irradiation has received limited attention in prior studies. To gain a fundamental understanding of the irradiation damage in V, its microstructure evolution under 6 MeV Ti ion irradiation at 25–500 °C is investigated in the present study, with the focus on the detailed and comprehensive characterization of the behavior of the irradiation-introduced dislocation loops. Under room temperature irradiation, the “black dot” dislocation loops agglomerate linearly into rafts, during which their Burgers vectors are well aligned. With the temperature increases to 300 °C, the size of rafts increases and the density decreases, while the size of small loops maintains similar to the room temperature irradiation condition. As the irradiation temperature reaches 500 °C, the defects become highly mobile, resulting in the formation of extended dislocation loops or lines with hundreds of nanometers in size, with the rafts vanishing. All the observable loops under this irradiation temperature range exhibit the Burgers vectors of a/2 < 111>. All the loops observed in the displacement region are identified to be interstitial-type, while a small portion of loops observed in the diffusion region under elevated temperatures are vacancy-type.

Site-Specific Location of Black Phosphorus Quantum Dot Cluster-Based Nanocomplexes for Synergistic Ion Channel Therapy and Hypoxic Microenvironment Activated Chemotherapy.

The spatiotemporal regulation of ion transport in living cell membrane channels has immense potential for providing novel therapeutic approaches for the treatment of currently intractable diseases. So far, most strategies suffer from uncontrolled ion transport and limited tumor therapy effects. On the premise of low toxicity to healthy tissues, enhancing the degree of ion overloading and the effect of tumor treatment still remains a challenging concern. Herein, an innovative strategy for synergistic ion channel therapy and hypoxic microenvironment activated chemotherapy is proposed. Biocompatible AQ4N/black phosphorus quantum dot clusters@liposomes (AQ4N/BPCs@Lip) nanocomplexes are site-specifically immobilized on the living cell membrane by a metabolic labeling strategy, eliminating the need for modifying or genetically encoding channel structures. Ascribing to the localized temperature increase of BPCs under NIR light irradiation, Ca2+ overinflux can be remotely controlled and the overloading degree was increased; moreover, the local released AQ4N can only be activated in the tumor cell, while it has no toxicity to normal cells. Compared with single intracellular Ca2+ overloading, the tumor cell viabilities decrease 2-fold with synergetic Ca2+ overloading-induced ion channel therapy and hypoxic microenvironment activated chemotherapeutics. Our study demonstrates the example of a remote-controlled ion influx and drug delivery system for tumor therapy.

From Hair-Pulling to Trichobezoars and Rapunzel Syndrome: A Comprehensive Review of Trichotillomania

Introduction: Trichotillomania (TTM) is an obsessive-compulsive disorder characterized by the uncontrollable pulling of hair from various parts of the body, most commonly from the scalp, eyebrows, and eyelashes. Clinical manifestations of TTM include patchy alopecia, uneven hair shaft growth, and characteristic changes visible in trichoscopy, such as the presence of black dots, twisted hairs, split ends, and hairs shaped like exclamation marks. The etiology of TTM is complex and involves genetic, neurological, and psychological factors. In some patients, TTM co-occurs with trichophagia, leading to the formation of trichobezoars in the gastrointestinal tract. In extreme cases, such as Rapunzel Syndrome, bezoars can lead to intestinal obstruction. Treatment for TTM is multifaceted and includes both psychotherapeutic and pharmacological interventions. Objective: The objective of this study is to provide a comprehensive review of trichotillomania (TTM), with a particular focus on its clinical symptoms, etiology, diagnostics, and treatment methods. The aim is to understand this obsessive-compulsive disorder, its impact on patients' lives, and its connections to serious complications such as trichobezoars and Rapunzel Syndrome. Materials and Methods: The study utilized analyses of scientific research, review articles, and reports concerning trichotillomania (TTM), trichobezoars, trichophagia, and Rapunzel Syndrome. It is primarily based on data from PubMed, Google Scholar, Cochrane Library, and studies published between 2000 and 2024, focusing on the diagnostics, etiology, and treatment of TTM and related disorders. Conclusions: The purpose of this study is to provide a comprehensive review of the current knowledge on trichotillomania, including its clinical symptoms, etiology, diagnostics, and treatment methods, while considering serious complications such as trichobezoars and Rapunzel Syndrome.

Real-life effectiveness and safety of baricitinib in patients with severe alopecia areata: A 24-week Italian study.

Alopecia areata is an autoimmune condition characterized by rapid hair loss in the scalp, eyebrows and eyelashes, for which treatments are limited. Baricitinib, an oral inhibitor of Janus kinases 1 and 2, has been recently approved to treat alopecia areata. We conducted a retrospective study involving 23 medical centres across Italy, enrolling patients affected by severe alopecia areata (SALT >50), for more than 6 months. Clinical and trichoscopic assessment was performed at each visit and impact on quality of life, anxiety and depression were evaluated using the Skindex-16 and the Hospital Anxiety and Depression Scale (HADS), respectively. A total of 118 patients were enrolled, with a mean age of 39 years and a mean SALT >95. The mean value of the SALT score decreased from an average of 96.6 (±8.23 sd) to 48 (±35.2 sd) after 24 weeks of treatment and 42.3% of patients achieved a SALT 30, 31.3% a SALT 20 and 20.3% a SALT 10 by Week 24. Trichoscopic signs showed fewer yellow dots and black dots significantly earlier than hair regrowth. Adverse events during the treatment period (mild laboratory test abnormalities) were reported in 12.7% patients. No drop-out were registered. Data on the effectiveness and safety of baricitinib are promising and support the use of this drug in severe forms of AA, also in the early stages. We also suggest performing trichoscopy in order to reveal early response to therapy.

An Automated pre-Dilution Setup for Von Willebrand Factor Activity Assays.

Accurate quantification of von Willebrand factor ristocetin cofactor activity (VWF:RCo) is critical for the diagnosis and classification of von Willebrand disease, the most common hereditary and acquired bleeding disorder in humans. Moreover, it is important to accurately assess the function of von Willebrand factor (VWF) concentrates within the pharmaceutical industry to provide consistent and high-quality biopharmaceuticals. Although the performance of VWF:RCo assay has been improved by using coagulation analyzers, which are specialized devices for blood and blood plasma samples, scientists still report a high degree of intra- and inter-assay variation in clinical laboratories. Moreover, high, manual sample dilutions are required for VWF:RCo determination of VWF concentrates within the pharmaceutical industry, which are a major source for assay imprecision. For the first time, we present a precise and accurate method to determine VWF:RCo, where all critical pipetting and mixing steps are automated. A pre-dilution setup was established on CyBio FeliX (Analytik-Jena) liquid handling system, and an adapted VWF:RCo method on BCS-XP analyzer (Siemens) is used. The automated pre-dilution method was executed on three different, most frequently used coagulation analyzers and compared to manual pre-dilutions performed by an experienced operator. Comparative sample testing revealed a similar assay precision (coefficient of variation = 5.9% automated, 3.1% manual pre-dilution) and no significant differences between the automated approach and manual dilutions of an expert in this method. While no outliers were generated with the automated procedure, the manual pre-dilution resulted in an error rate of 8.3%. Overall, this operator-independent protocol enables standardization and offers an efficient way of fully automating VWF activity assays, while maintaining the precision and accuracy of an expert analyst. Key features • Automated pre-dilution setup for von Willebrand factor concentrates of various natures. • Combination of a liquid handling system (CyBio FeliX) with a coagulation analyzer (BCS-XP). • Simplifies method transfer to other laboratories. • Basic training for CyBio FeliX and BCS-XP is required. Graphical overview VWF:RCo assay principle and measurement setup. Platelets (yellow ellipsoids) with negative surface charge (- - -) are treated with formaldehyde, which partly denatures the cell surface and thus stabilizes platelets for use as assay reagents. Stabilized platelets (dark-yellow-framed yellow ellipsoids) are then brought in contact with ristocetin A (chemical structure shown; black dots), which binds to the platelet surface and facilitates binding of VWF (green circles). The graphs show an example of quantitative determination of platelet agglutination by measurement of light transmission, where increasing amounts of VWF increase light transmission over time. The photo in the left-bottom corner shows the CyBio FeliX setup for VWF sample dilution and the photo in the right-bottom corner displays the BCS-XP system, which is used for VWF:RCo measurements.

Self-Assembled Hybrid Halide Perovskite Quantum Wire Bundle/Dot for Multiband Applications.

In this study, self-assembled halide perovskite quantum wire bundles (QWBs)/quantum dots (QDs) are fabricated using a room temperature-based formation method. The one-dimensional (1D) perovskite-based QWB structures incorporate zero-dimensional QDs within a composite quantum structure. Transmission electron microscopy reveals that quantum wires with diameters ranging from tens of nanometers to approximately 200 nm maintain a single-crystal atomic arrangement in a bundle form. Conversely, QDs are uniformly distributed within the single-phase wire and appear as black dots < 10 nm. Photoluminescence analysis identifies the multiband characteristics of the emissions. The 420-440 nm band is attributed to 1D QWB, whereas the peak appearing in the 530-550 nm range corresponds to lead halide PbBr2 QDs. Thus, the proposed self-assembled 1D QWB/QD composite structure exhibits novel multiband physical properties in the 420-440 and 530-550 nm bands; it offers new opportunities for designing materials with potential applications in optoelectronic devices.

Investigation of machining performance of waspaloy using copper-graphite composite electrodes in electric discharge machining

Abstract This study endeavoured to investigate the machining of Waspaloy using Electric Discharge Machining (EDM), utilizing copper-graphite composites as the tool material. Given the limited existing research on machining Waspaloy with composite tools, this study aims to address this gap by employing a copper-graphite composite tool. In this work, pure copper electrode and three composite electrodes with varying graphite percentages in copper, viz. copper containing 5%, 10%, and 15% graphite (CuGr-5, CuGr-10, and CuGr-15), are utilized for experimentation. Composite electrodes are fabricated by the stir-casting process. The scanning electron microscope reveals that the graphite specks are homogeneously disseminated over the matrix material. The Taguchi mixed orthogonal array was used for developing experimental runs. By varying the current, polarity, pulse on and off times, tool materials, and gap, machining performance was measured in terms of Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (Ra). It was observed that CuGr-5 provides an enhancement in MRR due to the improved electric conductivity, bridging effect, and increased energy concentration at the spark gap. Diverse characteristics witnessed on the surface morphology include black dots, globules, remelted layers, micro-cracks, and scratches. When machined with a CuGr5 electrode, the surface quality improved owing to the completed flushing and uniform distribution of generated heat as confirmed through worn surface morphology. The parameters were optimized utilizing the PROMETHEE optimization technique; it was found that the CuGr-5 electrode with the assessment value 0.02458 was optimal for machining of Waspaloy.

Influence of He injection amount on the microstructure of ion irradiated Cr0.8FeMnNi medium entropy alloy compared with 316L stainless steel

In recent years, medium and/or high-entropy alloys (M/HEAs) have attracted attention due to their excellent mechanical properties, positioning them as potential candidates for structural materials in advanced nuclear reactors. This study investigated the effect of He injection amount on the microstructural evolution in Cr0.8FeMnNi MEA and 316L stainless steel. Helium atoms were injected, followed by Fe2+ irradiation. Transmission electron microscopy was used to characterize the irradiation-induced defects. The primary irradiation-induced defects observed across all He injection amounts were black dots; no voids were seen under any irradiation conditions. In He-injected Cr0.8FeMnNi, the number density of black dots was significantly lower than in non-He-injected Cr0.8FeMnNi, while the average size of black dots increased with higher He injection rates. As the He injection amount increased, the binding energy of the self-interstitial atom (SIA) to the He-V complex decreased. This reduction facilitated the nucleation and growth of numerous SIA clusters within the matrix, consequently increasing the number density of black dots. The change in the number density of black dots in Cr0.8FeMnNi was much smaller than that observed in 316L. This could be ascribed to the enhanced self-healing process caused by the diversity of point defects and higher lattice distortion in Cr0.8FeMnNi.

Clinical and Dermoscopic Patterns of Basal Cell Carcinoma and Its Mimickers in Skin of Color: A Practical Summary.

The diagnosis of basal cell carcinoma (BCC) in dark phototypes can be a challenging task due to the lack of relevant clues and its variable presentation. In this regard, there is growing evidence that dermoscopy may benefit the recognition of BCC even for skin of color (SoC). The objective of this review is to provide an up-to-date overview on clinical and dermoscopic patterns of BCC in SoC, also comparing such findings with those of the main clinical mimickers reported in the literature. A comprehensive search of the literature through the PubMed electronic database was carried out in order to identify papers describing the clinical and dermoscopic features of BCC in dark phototypes (IV-VI). By finding macroscopic clinical presentations of BCCs in SoC patients and any possible clinical mimickers considered in the retrieved papers, we built a differential diagnosis list and analyzed the dermoscopic findings of such conditions to facilitate the diagnosis of BCC. BCC in darker skin may present as pigmented nodular lesions, pigmented patches or plaques, ulcers, erythematous nodular lesions, erythematous plaques or patches, or scar-like lesions, depending on its subtype and body site. The differential diagnosis for BCC in patients with SoC includes squamous cell carcinoma, melanoma, nevi, adnexal tumors and sebaceous keratosis. Additionally, it differs from that of Caucasians, as it also includes lesions less common in fair skin, such as dermatosis papulosa nigra, melanotrichoblastoma, and pigmented dermatofibrosarcoma protuberans, and excludes conditions like actinic keratosis and keratoacanthoma, which rarely appear in darker skin. The resulting differences also include infectious diseases such as deep cutaneous mycosis and inflammatory dermatoses. The most prevalent differentiating dermoscopic feature for BCC includes blue, black and gray dots, though arborizing vessels still remain the predominant BCC feature, even in dark phototypes. Diagnostic approach to BCC in dark-skinned patients varies due to the prevalence of dermoscopy findings associated with hyperpigmented structures. Clinicians should be aware of such points of differentiation for a proper management of this tumor in SoC.

Preparation of TiO2 nanotube array/black phosphorus hydrogel drug slow release system based on reactive oxygen response

Black phosphorus quantum dots (BPQDs) were prepared by liquid stripping method, combined with a gel with reactive oxygen species (ROS) decomposition property, and wrapped onto TiO2 nanotube arrays loaded with ibuprofen (IBU) to construct a drug delivery system with near-infrared light (NIR) stimulation response. The generated ROS due to the presence of BPQDs can not only break the dynamic covalent bonds in the gel structure, leading to the decomposition of the gel, achieving NIR-responsive release of IBU and accelerating the release rate of IBU, but at the same time, ROS can play an obvious antibacterial role.

Wear and neutron shielding resilience of titanium-hexagonal boron nitride coatings against extreme lunar radiation and thermal cycles

Ti6Al4V and Al6061 are aerospace alloys used in lunar structural components and rovers owing to their high specific strength. However, they deteriorate rapidly when subjected to demanding conditions of the lunar environment, such as extreme thermal cycles, solar particle radiation, and abrasive regolith. Cryo-milled powders were employed to deposit hBN-reinforced protective titanium coatings through plasma spray (atmospheric-APS and vacuum-VPS) with 2 and 10 vol% of hBN on Ti6Al4V and Al6061 substrates. These coatings were evaluated for durability under extreme lunar-like conditions, including thermal cycling, electron radiation, and synergistic (electron radiation-thermal cycle) exposure. The coatings exhibited radiation-induced hardening, resulting in a substantial increase in their microhardness ~20–40 % compared to virgin condition. Bright-field transmission electron microscopy (TEM) analysis reveals the presence of high dislocation densities, black dot defects, and dislocation clusters, providing evidence of the severe impact of synergistic environmental stresses. Ball-on-disk tribological tests were conducted in the presence of JSC-1 A lunar regolith simulant to evaluate the wear performance of coatings. Compared to conventional Ti6Al4V substrate, 50 %, 90 %, and 70 % reductions in wear volume were observed in the Ti/2 vol% hBN coatings in thermal-only, radiation-only, and synergistic environments. Neutron shielding tests indicate that the synergistic coatings offer higher neutron shielding performance by up to 28 % compared to virgin coatings, attributed to improved neutron capture by 10B isotopes. Upon a comprehensive assessment and ranking of multiple coatings under varying conditions, the VPS Ti/2 vol% hBN coating emerges as the top choice for protection against extreme radiation and thermal cycles for future lunar explorations.