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A fluorescent and colorimetric dual-mode strategy based on carbon dots (CDs) was rationally designed for sensitive determination of Cu2+. Green fluorescent CDs with high absolute quantum yield of 72.9% were synthesized by facile one-step hydrothermal treatment of triethylenetetramine and Rose Bengal. Cu2+ could trigger the oxidative and chromogenic reaction of p-phenylenediamine (PPD) to generate chromogenic PPDox, accompanied by the fluorescence quenching of the CDs. The quenching mechanism was identified as the inner filter effect between PPDox and CDs. Therefore, a colorimetric/fluorescent dual-mode detection method for Cu2+ recognition was constructed. The limits of detection for Cu2+ were 4.14 μM and 1.28 μM for colorimetric and fluorescent mode, respectively. In addition, this method had achieved satisfactory results in the detection of Cu2+ in real serum samples. [ABSTRACT FROM AUTHOR]

A ratiometric fluorescence probe based on carbon quantum dots with 420 nm emission (bCQDs) and a p-phenylenediamine-derived fluorescence probe with 550 nm emission (yprobe) is constructed for the detection of Mn2+. The presence of Mn2+ results in the enhanced absorption band at 400 nm of yprobe, and the fluorescence of yprobe is significantly enhanced based on the chelation-enhanced fluorescence mechanism. The fluorescence of bCQDs is then quenched based on the inner filtration effect. The ratio (I550/I420) linearly increases with the increase of Mn2+ concentration within 2.00 × 10−7–1.50 × 10−6 M, and the limit of detection is 1.76 × 10−9 M. Given the fluorescence color changing from blue to yellow, the visual sensing of Mn2+ is feasible based on bCQDs/yprobe coupled with RGB value analysis. The practicability of the proposed method has been verified in tap water, lake water, and sparkling water beverage, indicating that bCQDs/yprobe has promising application in Mn2+ monitoring. [ABSTRACT FROM AUTHOR]

Background: Previous studies reported a low‐to‐moderate benefit from patch testing regarding allergen recall and avoidance. Objectives: To determine the allergen recall and avoidance rates of patients with allergic contact dermatitis (ACD) in Turkey. Methods: This was a retrospective cohort study based on a phone questionnaire of 465 patients diagnosed with ACD from major allergen groups, that is, metals, preservatives, rubber, fragrances (ubiquitous allergens) and hair dye/black henna, topical drug and resins (nonubiquitous allergens), at our tertiary referral centre between 1996 and 2018. Results: Among 176 responders, allergen groups were remembered better (53.4%) than the individual allergens (36.9%). Age <40 years and keeping the allergy pass had a significantly positive impact on the recall rate of methylchloroisothiazolinone/methylisothiazolinone and nickel, particularly non‐occupational nickel allergy from metal jewellery in females, respectively. Exacerbations of ACD (56.3%) were mainly due to reexposures to ubiquitous allergens. 42.9% of patients with occupational ACD changed or quit their job, most of them being construction workers and hairdressers, showing a high share (83.3%) of benefit. Conclusions: The overall rates of allergen recall and avoidance were moderate. New strategies are needed to improve the recall and avoidance rates of contact allergens, such as increased use of allergy pass, smartphone applications and legal precautions. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) doped with heteroatoms have garnered significant interest due to their chemically modifiable luminescence properties. Herein, nitrogen- and sulfur-codoped carbon dots (NS-CDs) were successfully prepared using p-phenylenediamine and thioacetamide via a facile process. The as-developed NS-CDs had high photostability against photobleaching, good water dispersibility, and excitation-independent spectral emission properties due to the abundant amino and sulfur functional groups on their surface. The wine-red-colored NS-CDs exhibited strong green emission with a large Stokes shift of up to 125 nm upon the excitation wavelength of 375 nm, with a high quantum yield (QY) of 28%. The novel NS-CDs revealed excellent sensitivity for quercetin (QT) detection via the fluorescence quenching effect, with a low detection limit of 17.3 nM within the linear range of 0–29.7 μM. The fluorescence was quenched only when QT was brought near the NS-CDs. This QT-induced quenching occurred through the strong inner filter effect (IFE) and the complex bound state formed between the ground-state QT and excited-state NS-CDs. The quenching-based detection strategies also demonstrated good specificity for QT over various interferents (phenols, biomolecules, amino acids, metal ions, and flavonoids). Moreover, this approach could be effectively applied to the quantitative detection of QT (with good sensing recovery) in real food samples such as red wine and onion samples. The present work, consequently, suggests that NS-CDs may open the door to the sensitive and specific detection of QT in food samples in a cost-effective and straightforward manner. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The crimping and aggregation of graphene in the matrix often affect the properties of the composites. Herein, we successfully constructed the fluorinated graphene oxide (FGO) with interlayer support structure to improve the properties of epoxy composites. We employed diamine as a spacer and investigated the effects of three diamines with different structures on the modification of FGO in detail. FGO modified by p-phenylenediamine (PPD-FGO) had maximum interlayer spacing, presenting good stability and antiaggregation properties. Moreover, the addition of PPD-FGO makes epoxy resin composite transform from brittle material to ductile material, and the impact strength was significantly improved at both room temperature and 77 K. Meanwhile, the thermal properties were maintained very well, showing a slight increase. In addition, PPD-FGO/epoxy composite coating displayed good anti-corrosion performance for carbon steel. This work not only provides a new method to improve the properties of epoxy resin but also gives a new direction for the application of FGO. [ABSTRACT FROM AUTHOR]

Polycarbonate is a commonly used plastic, particularly for making glasses lenses. Polycarbonate is prone to fogging, making hydrophilic modification desirable. In this work, polycarbonate is treated with p-phenylenediamine (PPD) to improve its hydrophilicity. The influence of treating conditions, such as solvent, PPD concentration, heating temperature, and heating time, are studied to reveal their impacts on the water contact angle of polycarbonate. For example, the water contact angle of polycarbonate is reduced to 33° from 83° after treated in water with 0.1 wt% PPD at 80°C for 120 minutes. The improvement of the hydrophilicity of polycarbonate by PPD is explained based on the introduction of polar groups by PPD or poly-PPD (p-PPD), in terms of polyurethane, benzyl hydroxyl, or amine centers, which can interact with water to have a better affinity to spread water on the surface due to the like-like principle. The possible mechanisms are supported with infrared spectroscopy measurements. [ABSTRACT FROM AUTHOR]

The low temperature atmospheric plasma are kinds of advanced oxidation processes (AOPs) reactors and have potential applications on gas cleaning and water treatment; however, the underlying reaction mechanisms of organic compounds degradation are not well understood. In this study, the gas phase multistep OH‐initiated dehydrogenations of p‐, m‐, and o‐phenylenediamine with C2h, C2, and C2 point groups were investigated using density functional theory. Intrinsic reaction calculations were performed for transition states at the M062X/Def2TZVPP level of theory. The distinct directed graphs of the predominant pathways are presented to elucidate the dehydrogenation processes of three isomers of phenylenediamines. The information reported in this paper reveals the AOPs of phenylenediamines. [ABSTRACT FROM AUTHOR]

Chemistry laboratory training is an integral part of chemistry teaching. However, outdated experimental protocols present limitations and can hinder students’ initiative and innate inclination toward exploration. In this study, novel scientific concepts were translated into experimental chemistry teaching. Small fluorescent molecules with aggregation-induced emission and excited-state intramolecular proton transfer properties were prepared using a carbonyl nucleophile addition reaction. The basic photophysical properties of the molecules and their fluorescence response to acid-base stimulation were evaluated experimentally. The non-toxic and non-noxious reagents used for the experiments were refluxed in ethanol for 0.5 h to implement green organic synthesis principles. The experiment was compact and the fluorescence and color changes of the as-synthesized molecules were conspicuous and remarkable. This can stimulate students’ enthusiasm for experimental chemistry. In addition to the basic organic synthesis reaction, this experiment included several modern analysis and characterization methods, such as nuclear magnetic resonance, Fourier-transform infrared spectroscopy, ultraviolet-visible absorption spectroscopy, and fluorescence spectroscopy. We are confident that this intuitive and effective basic experiment can effectively stimulate and cultivate the innate curiosity of students. [ABSTRACT FROM AUTHOR]

Automobiles use compression-ignition (CI) engines because they have more pulling power, are more dependable and use less fuel than spark-ignition (SI) engines. Both CI and SI engines use petroleum-based oils, contributing to environmental pollution like acid rain, ozone depletion and climate change. The cost of petroleum-based fuel is increasing daily due to demographic growth and the development of manufacturing industries. There are four phases to the experiments. The first stage involves mixing diesel with 20% of ALME, the outcomes showed that engine operation and combustion are comparable to conventional diesel fuel. In the second stage, an LHR engine tests 20% of ALME and the results showed that BTE of LHR engine had significantly increased. In comparison, NOx increases in LHRoperated CI engine, CO, HC and smoke emissions are significantly lower than with a conventional engine. The third stage looks at how NA interacts with biodiesel to affect conventional engine's combustion, emission and engine performance. The prepared algae biodiesel is blended with NA in various ratios of 500ppm, 1000ppm, 1500ppm and 2000ppm. At 1000ppm concentration, NOx emission from conventional and LHR engines has been effectively minimized under load conditions. Concerning diesel fuel, emissions like CO, HC and smoke are significantly reduced for all loads. In the fourth stage, tests on the LHR engine are carried out using the SBME with NA in various proportions. When compared to base fuel, it has been found that NOx emission has decreased significantly at 1000ppm compared to conventional engines and other emissions have decreased. [ABSTRACT FROM AUTHOR]

In contrast to standard fuel, biodiesel continues to burn cleaner. However, repeated studies have revealed that when compared to conventional diesel fuel, biodiesel generates more NOx formation. In this research, methyl ester of Annona (AOME) oil is applied to produce biodiesel by a transesterification process. The antioxidant is administered in varying quantities in w/w basis ranging from 0.010 to 0.040%. Without altering the engine, the findings suggest that the antioxidant additive mixture AOME+P200 is effective in lowering NOx and HC emissions of AOME fuelled engines. [ABSTRACT FROM AUTHOR]

Background: This study investigated cases diagnosed as allergic contact dermatitis (ACD) in emergency departments (EDs) and management. Methods: A multisite retrospective study of patients attending EDs in metropolitan Melbourne between July 2017 and June 2018 was performed. Using International Statistical Classification of Disease‐10 (ICD‐10) codes, the Victorian Agency for Health Information generated a list of cases of contact dermatitis (CD). Demographic and clinical data were analysed. Results: Two hundred twenty‐eighty patients from 14 different sites were diagnosed with ACD. Hair dyes caused the most cases, and one such case was admitted to hospital. It was apparent from the specified causes that cases of irritant CD were misdiagnosed as ACD. There were significant differences in management with dermatology input, with dermatologists more often advising oral corticosteroids (33.3% vs. 14.5%, P = 0.004) topical corticosteroids (92.9% vs. 38.7%, P < 0.01), emollients (38.1% vs. 20.4%, P = 0.01) and less often advising antihistamines (16.7% vs. 44.6%, P < 0.001). With dermatology input, potent or very potent steroids were more likely to be prescribed (69.3% vs. 11.1%, P < 0.001); without, a mild potency steroid was more likely to be prescribed (63.9% vs. 4%, P = 0.01). Conclusion: Improved understanding, diagnosis and management of CD are needed in EDs. [ABSTRACT FROM AUTHOR]

Red phosphorus (RP) is a promising electrochemical sensing material owing to its abundant surface groups and reactive sites. In this study, a sodium dodecyl sulfate‐assisted phosphorus‐amine approach is employed to tune surface chemistry of RP nanoparticles. During the transition of the polyphosphorus‐amine anion to RP, the cleavage of POP bond and the formation of POC bond are monitored by in situ attenuated total reflection surface‐enhanced infrared absorption spectroscopy. The formed POC bonds that are originated from the PO reactive sites are theoretically revealed with the density functional theory calculations, charge density difference, and X‐ray photoelectron spectroscopy. The energies of optimized aromatic and aliphatic POC bonds are −2.51 and −2.65 eV, respectively. To explore electrochemical sensing applications, RP nanoparticles are in situ grown on single‐walled carbon nanotube (SWCNT). Such a stable RP/SWCNT suspension is applied to fabricate the RP/SWCNT integrated arrays via a template‐filtration method. Such an array is efficient for sensitive and selective monitoring of p‐phenylenediamine on hair dyes. This study provides insights into surface chemistry of RP, its roles in electrochemical sensing applications, and an approach to produce high‐performance RP sensors at large scales. [ABSTRACT FROM AUTHOR]

In the deep-sea environment, it is difficult to enhance the anti-corrosion properties of a metal substrate of epoxy coating (EP) on Ti 3 C 2 T x nanosheets by a single physical barrier mechanism. Thus, to reduce the corrosion on the metal surface, Ti 3 C 2 T x -embodying epoxy coatings with superior barrier performance along with self-healing function can be quite desirable. In this study, p-phenylenediamine (PPD) functionalized Ti 3 C 2 T x was synthesized, and then PPD-Ti 3 C 2 T x nanohybrids used as filler to engraft the epoxy coating using superior physical barrier along with self-healing ability. This anti-corrosion property of PPD-Ti 3 C 2 T x /EP coating was investigated by the electrochemistry test in the saline solution (NaCl, 3.5 wt %). The cross-sectional structure of the compound coating confirmed that 0.5PPD-Ti 3 C 2 T x significantly enhanced the tightness of EP coating, and the adhesion intensity of the 0.5PPD-Ti 3 C 2 T x /EP coating was four times than that of the blank epoxy coating after immersing for 10 days by alternating hydrostatic pressure (AHP). The impedance modulus of 0.5PPD-Ti 3 C 2 T x was four orders of magnitude higher than that of absolute epoxy coating after 10 days of immersing in AHP, which was attributed to the effective shielding performances of well-dispersed PPD-Ti 3 C 2 T x and self-healing ability of PPD inhibitor. The analysis of corrosion products clarified that PPD could facilitate formation of passive film consisting of Fe 2 O 3 along with Fe 3 O 4 , indicating superior self-healing capacity. [Display omitted] • We synthesized a novel PPD-Ti 3 C 2 T x hybrids. • Barrier/self-healing dual-function PPD-Ti 3 C 2 T x /EP coating application in deep-sea. • The anticorrosion properties of 0.5PDD-Ti 3 C 2 T x keep well under AHP for 10 days. • PPD promoted the formation of passive film (composed of Fe 2 O 3 and Fe 3 O 4) on steel. [ABSTRACT FROM AUTHOR]

Keywords: allergic contact dermatitis; Alopecia areata; case report; hair dye; hair loss; henna tattoos; multiple sclerosis; non-scarring alopecia; PPD; p-phenylenediamine EN allergic contact dermatitis Alopecia areata case report hair dye hair loss henna tattoos multiple sclerosis non-scarring alopecia PPD p-phenylenediamine 536 539 4 11/11/22 20221201 NES 221201 Several types of alopecia may be triggered by scalp allergic contact dermatitis (ACD) including telogen effluvium1 and scarring alopecia.2 We hereby describe an unusual case of alopecia areata (AA) activated by severe ACD to a permanent hair dye. Two years after the events of ACD and AA, the patient was subsequently diagnosed with multiple sclerosis (MS). In predisposed individuals, MS may be diagnosed prior to or after AA.10 AA may also be triggered by alemtuzumab, a therapy used in MS. [Extracted from the article]

To investigate whether p-Phenylenediamine (PPD) could triggered EMT inSV-40 immortalized human urothelial cells (SV-HUC-1), and the regulation role of ERK5/AP-1 during this process. SV-HUC-1 cells were treated with different concentrations of PPD. MTT assay was employed to detect cell viability. Wound healing and transwell assay were performed to detect migrative and invasive capacity. Western blot and qRT-PCR were utilized for detecting molecular changes. ERK5 specific inhibitor was used to suppress ERK5 signaling. Migration and invasion capacity of SV-HUC-1cells were enhanced after PPD exposure. Expression of epithelial markers E-cadherin and ZO-1 was decreased and expression of mesenchymal markers N-cadherin and vimentin was increased after being cultured with low concentrations of PPD, indicating that PPD induced EMT in PPD-cultured SV-HUC-1 cells. Meanwhile, PPD triggered activation of ERK5signaling and downstream AP-1 was activated, but no obvious influence of PPD on other sub-families of MAPK was detected. After inhibition of ERK5/AP-1, PPD-induced enhancement of migrative and invasive abilities were attenuated and expression of EMT markers was also reversed. PPD may be a carcinogen, which could induce EMT in SV-40 immortalized human urothelial cells (SV-HUC-1) via activating ERK5/AP-1 signaling. • PPD induces EMT in SV-40 immortalized human urothelial cells. • PPD activates ERK5 rather ran other member of MAPK families. • ERK5 positively regulates PPD related EMT in SV cells. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A novel synergistic effect of TiO2 and ZnO incorporation in the PES-based thin-film nanocomposite nanofiltration membranes was developed for the treatment of common effluent treatment plant (CETP) textile wastewater. PES@TiO2 membranes were developed by phase inversion via the immersion precipitation method followed by the addition of zinc oxide nanoparticles prepared by the rapid microwave-assisted hydrothermal process via interfacial polymerization. p-Phenylenediamine was used as a monomer for the IP process that was coated on the PES@TiO2 support layer. Various techniques have been applied to characterize the developed thin-film nanocomposite membranes such as Fourier transform infrared (FTIR) microscopy, field emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD), and contact angle measurement to examine the presence of vibrational modes, surface morphology, the crystal structure of nanoparticles, and hydrophilicity of the membrane, respectively. Membrane properties include porosity, salt rejection, mean pore radius, pure water flux, and industrial effluent rejection efficiency that were studied. The thin-film nanocomposite membrane T5-PES@TiO2(2%)-ZnO(0.3%) was prepared with a combination of 17 wt% PES, 78 wt% DMF, 3 wt% PVP K30, 2% TiO2, 2.5 wt% PPD, 0.3 wt% ZnO, and 1.0 wt% TMC that exhibited high water permeability, porosity, higher industrial effluent rejection, and salt rejection efficiency compared to the neat PES membrane. [ABSTRACT FROM AUTHOR]

Background. Hemoglobin is a hemoprotein which in the presence of oxidative equivalents, such as H2O2, can act as peroxidase with a very high oxidative potential. Hemoglobin oxidation is accompanied by generation of highly oxidized forms of iron and globin radicals that have high oxidative activity and are toxic to cells. In addition, peroxidase activity may indicate structural changes that occur in the hemoglobin molecule as a result of chemical modification. Materials and Methods. Erythrocyte suspension was subjected to vibration for 3 h within the frequency range from 8 to 32 Hz with amplitudes of 0.5 ± 0.04 and 0.9 ± 0.08 mm. At certain intervals, hemoglobin peroxidase activity was determined together with the content of its ligand forms in the hemolysates of cells. Additionally, experiments were performed to investigate the mechanism and calculate the kinetic parameters of peroxidase reaction. Results and Discussion. Experimental data on low-frequency vibrations effect on erythrocyte hemoglobin peroxidase activity were analyzed. The kinetics of the oxidation reaction of p-phenylenediamine by hemoglobin in erythrocytes was studied. It was found that peroxidase oxidation has a ping-pong mechanism. The kinetic parameters of the peroxidase reaction involving hemoglobin were determined. The change of kinetic parameters after two-hour exposure to the incubation medium and low-frequency vibration was studied. A possible mechanism of action of hemoglobin in oxidation reactions involving H2O2 was proposed. Conclusion. Any effect that initiates the formation of methemoglobin leads to an increase in the peroxidase activity of hemoglobin due to the involvement of the latter in the pseudoperoxidase cycle and the formation of toxic reactive globin radicals. The high content of oxyhemoglobin in the cell, observed under vibrations within the frequency range of 16–32 Hz with an amplitude of 0.9 ± 0.08 mm, can prevent its oxidation and involvement in the pseudoperoxidase cycle.

Metal-organic frameworks (MOFs) have attracted extensive attention as precursors for the preparation of carbon-based materials due to their highly controllable composition, structure, and pore size distribution. However, there are few reports of MOFs using p-phenylenediamine (pPD) as the organic ligand. In this work, we report the preparation of a bimetallic MOF (CoCu-pPD) with pPD as the organic ligand, and its derived hollow carbon spheres (BMHCS). CoCu-pPD exhibits a hollow spherical structure assembled by nanosheets. BMHCS inherits the unique hollow spherical structure of CoCu-pPD, which also shows a large specific surface area and heteroatom doping. When using as the anode of sodium-ion batteries (SIBs), BMHCS exhibits excellent cycling stability (the capacity of 306 mA h g−1 after 300 cycles at a current density of 1 A g−1 and the capacity retention rate of 90%) and rate capability (the sodium storage capacity of 240 mA h g−1 at 5 A g−1). This work not only provides a strategy for the preparation of pPD-based bimetallic-MOFs, but also enhances the thermal stability of the pPD-based MOFs. In addition, this work also offers a new case for the morphology control of assembled carbon materials and has achieved excellent performance in the field of SIBs. [ABSTRACT FROM AUTHOR]

Aluminum is a kind of metal that we often encounter. It can also be absorbed by the human body invisibly and will affect our bodies to a certain extent, e.g., by causing symptoms associated with Alzheimer's disease. Therefore, the detection of aluminum is particularly important. The methods to detect metal ions include precipitation methods and electrochemical methods, which are cumbersome and costly. Fluorescence detection is a fast and sensitive method with a low cost and non-toxicity. Traditional fluorescent nanomaterials have a high cost, high toxicity, and cause harm to the human body. Graphene quantum dots are a new type of fluorescent nanomaterials with a low cost and non-toxicity that can compensate for the defects of traditional fluorescent nanomaterials. In this paper, c-GQDs and o-GQDs with good performance were prepared by a bottom-up hydrothermal method using o-phenylenediamine as a precursor and citric acid or boric acid as modulators. They have very good optical properties: o-GQDs exhibit orange fluorescence under UV irradiation, while c-GQDs exhibits cyan fluorescence. Then, different metal ions were used for ion detection, and it was found that Al3+ had a good quenching effect on the fluorescence of the o-GQDs. The reason for this phenomenon may be related to the strong binding of Al3+ ions to the N and O functional groups of the o-GQDs and the rapid chelation kinetics. During the chelation process, the separation of o-GQDs' photoexcited electron hole pairs leads to their rapid electron transfer to Al3+, in turn leading to the occurrence of a fluorescence-quenching phenomenon. In addition, there was a good linear relationship between the concentration of the Al3+ ions and the fluorescence intensity, and the correlation coefficient of the linear regression equation was 0.9937. This illustrates the potential for the wide application of GQDs in sensing systems, while also demonstrating that Al3+ sensors can be used to detect Al3+ ions. [ABSTRACT FROM AUTHOR]

In this study, p-Phenylenediamine supported on nanocellulose (PDA@CNC) was designed. The prepared nanocatalyst was characterized with various analytical techniques such as FT-IR, XRD, TGA, SEM, and CHN. Nanocatalyst used for the synthesis of spiropyran oxide derivatives by designing a simple and efficient method using a three-part reaction between the Isatin derivatives, Malononitrile or Ethyl cyanoacetate and 1,3-dicarbonyl compound. Simple procedure, high yields, short reaction time and environmentally benign method are advantages of this protocol. The nanocatalyst was readily separated by filter and reusable without significant loss of its catalytic efficiency. [ABSTRACT FROM AUTHOR]

Thermal management has become an important requirement for many types of electrical equipment due to the development of integrated circuits. In this study, modified and reduced graphene fillers were synthesized in two steps, and then epoxy resin was filled through the evaporation of the solvent. The interfacial thermal resistance between the filler and matrix material was lowered by including amino groups to improve graphene compatibility in the epoxy resin. Furthermore, the reduction procedure was shown to have the potential to fix graphene oxide flaws, thereby improving thermal stability, electrical conductivity, and thermal conductivity of the composites. As a result, the thermal conductivity of the composite reached 1.7 W/mK, which is 750% higher than that of pure epoxy resin, and it was still insulated. [ABSTRACT FROM AUTHOR]

Antimicrobial textiles have played an increasingly important protection role in the medical field. With this aim, Schiff bases and nanometal complexes on the cotton fabric were in situ synthesized for achieving the conventional cotton fabric's highly efficient and durable UV protection and antibacterial properties. Herein, a new Schiff base derived from the condensation reaction of 2,4-dihyroxybenzaldehyde with p-amino aniline was synthesized. Co, Ni, Cu, and Zn complexes of the Schiff base were also prepared and characterized by UV-Vis, Fourier-transform infrared spectroscopy, 1HNMR, 13CNMR, elemental analysis, and thermal analysis. The modified cotton fabric was also characterized via X-ray diffraction, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transition electron microscope (TEM), and Energy Dispersive X-Ray Analysis (EDX). Moreover, the microbial, UV protection, and tensile strength of the samples were investigated. The antimicrobial was studied against Gram-positive bacteria, Gram-negative bacteria, and fungal strains. Modified cotton fabric exhibited highly antibacterial activity in contrast with fungal activity. These results depended on the Schiff base and the type of metal complex. The results also show that the cotton fabric modified by in situ nanometal complexes provides excellent UV protection. [ABSTRACT FROM AUTHOR]

p‐Phenylenediamine (p‐PDA) is a monomer of many important polymers such as kevlar, twaron, poly‐p‐PDA. Most of the noticed polymers formation is initiated by a free‐radical, but their polymerization mechanism is not elucidated computationally. The proposed study helps to fully understand the frequently utilized initiator/oxidant, potassium persulfate (K2S2O8) role in the aromatic diamines polymerization, which support experimental protocols, and a polymer scope. The formation of the poly‐p‐PDA is studied with the density functional theory (DFT) B3LYP‐D3 functional using experimental polymerization parameters (0°C and aqueous media). K2S2O8 initiated free‐radical polymerization of p‐PDA is studied in detail, taking into account sulfate free‐radical (SO4−)·, SFR, persulfate anion (S2O8)2−, PA and K2S2O8 cluster, PP. The reaction mechanism is calculated as the conversion of p‐PDA to free‐radical, the p‐PDA free‐radical attack to the next p‐PDA (dimerization), ammonia extrusion from the dimer adduct, the dimer adduct conversion to the free‐radical (completion of p‐PDA polymerization cycle) for the polymer chain elongation. Calculations show that the dimerization step is the rate‐limiting step with a 29.2 kcal/mol energy barrier when SFR initiates polymerization. In contrast, the PA‐assisted dimerization energy barrier is only 12.7 kcal/mol. PP supported polymerization is calculated to have very shallow energy barriers completing the polymerization cycle, i.e., dimerization (TS2K, ∆G‡ = 11.6 kcal/mol) and ammonia extrusion (TS3K, ∆G‡ = 6.7 kcal/mol). [ABSTRACT FROM AUTHOR]

Surface modification of p-phenylenediamine-derived carbon dots using 4-morpholinoaniline with an electron-donating and rigid structure followed by purification using silica gel column chromatography increased the photoluminescence quantum yield from 28.3 to 41.8% in chloroform. The improved photoluminescence quantum yield was observed for the surface modification by postaddition of the surface modifier after the formation of the π-conjugated structure of the carbon dot core but was not observed for the carbon dots prepared from a mixture of p-phenylenediamine and 4-morpholinoaniline. The finding of this work gives us an idea to design carbon dots with high photoluminescence quantum yield for application of color conversion in white-light-emitting diodes. [ABSTRACT FROM AUTHOR]

p -Phenylenediamine (PPD) serves as an important intermediate in materials chemistry and is widely used in the preparation of azo dyes and high polymers. However, the discharge of wastewater from industries containing PPD can pose significant threats to both the environment and human health. Herein, a sensitive and reversible β-ketoenamine-based covalent organic framework (TD-COF) fluorescent probe was fabricated with ketoamine-substituted monomers for detection and facile removal of PPD. Abundant carbonyl groups, the regular pores, and the π-conjugated structure of TD-COF are the key features that help facilitate TD-COF interaction with the analyte. Based on these advantages, TD-COF displayed a low detection limit (0.35 μM), high sensitivity, easy visibility, real-time response, and selective interaction with PPD. Simultaneously, the effective removal of PPD and the circulating utilization of TD-COF provide the potential for practical production applications. Regeneration experimental studies indicated that TD-COF retained satisfactory structural stability after five cycles. Furthermore, based on solid-state NMR, X-ray photoelectron spectroscopy, and density functional theory calculations, these studies verified that hydrogen bonding and π-π interaction mechanisms contribute to fluorescence quenching between PPD and the carbonyl of TD-COF. The research demonstrated the utilization of fluorescent COFs for the sensing and removal of PPD, with the potential for extension to the detection of other pollutants. [Display omitted] • TD-COF has realized the selective detection of p -phenylenediamine. • The fluorescence quenching of TD-COF can be attributed to the formation of hydrogen bonds and π-π interaction between p -phenylenediamine and TD-COF. • The mechanism's contribution to fluorescence quenching has been confirmed through 13 C CP/MAS NMR, XPS, FT-IR, and DFT calculations. [ABSTRACT FROM AUTHOR]

41 Fragneaud, B., Masenelli-Varlot, K., Gonzalez-Montiel, A., Terrones, M., Cavaille, J. Y. Electrical behavior of polymer grafted nanotubes/polymer nanocomposites using N-doped carbon nanotubes. Keywords: electrical conductivity; multiwalled carbon nanotubes; nanocomposite; P-phenylenediamine; polysulfone EN electrical conductivity multiwalled carbon nanotubes; nanocomposite P-phenylenediamine polysulfone 418 427 10 05/09/22 20220501 NES 220501 1 Introduction Polysulfone (PSU) is a widespread polymeric material applied in various implementations. Carbon nanotubes (CNTs) have a role in boosting the performance of polysulfone. The diameter of the carbon nanotubes ranges between 6 and 13 nm with average length of 10 m. 2.2 Methods 2.2.1 Functionalization of multiwalled carbon nanotubes Multiwalled carbon nanotubes (MWCNTs) were functionalized upon being introduced to a concentrated solution of H SB 2 sb SO SB 4 sb and HNO SB 3 sb (3:1). [Extracted from the article]

One of the most industrially-prominent fibers, polyacrylonitrile (PAN), was chemically modified with the two specific steps to gain new functional groups that enable the surface chemically attractive. First, the chemically-susceptible epoxy groups were introduced to the PAN through graft copolymerization of glycidyl methacrylate using benzoyl peroxide (Bz2O2) as an initiator. Secondly, the surface of GMA grafted-PAN fibers (PAN-g-GMA) was decorated by the poly(p-phenylenediamine) (PFDA) and Ag nanoparticles through the in-situ oxidative polymerization of p-phenylenediamine (p-FDA) using AgNO3. The changes in the PAN fiber's weights were monitored by changing the experimental conditions such as Bz2O2 and GMA concentrations, polymerization temperature-time, and AgNO3/p-FDA mol ratio. The usage of 5×10−3 M of Bz2O2 and 0.5 M of GMA at 85 °C for 1 h ensured over 95 % of GMA graft yields to the PAN-g-GMA fibers. Structural, thermal, and morphological changes that occurred in the PAN fiber were examined in detail using ATR-FTIR, XRD, TGA, Optical Microscope, and SEM techniques, respectively. A grey metallic shine was detected by optic microscopy on the composite surface after the PFDA/Ag nanoparticles deposition. Finally, the antibacterial activity performance of the Ag particles anchored-composite fiber was determined against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) by the zone inhibition test. The Ag particles decorated-composite showed high antibacterial activity, especially against E. coli (16.5 cm inhibition) compared to Ag-unloaded one. A suitable methodology was presented to develop a fiber composite that will potentially be used as an antibacterial textile in the various material preparation fields. [ABSTRACT FROM AUTHOR]

In order to obtain high specific capacitance of the electrode used for supercapacitors based on new carbon materials,graphene oxide(GO),from graphite oxidized by chemicals,was modified by oligomers of p-phenylenediamine in an autoclave.The changes of molecular structure of p-phenylenediamine oligomers in ethanol solution under different heating processes were tested by UV-vis spectroscopy.The structure,morphology,electrical storage performance and cycle stability of the composite were characterized by X-ray diffraction,field emission scanning electron microscopy,and cyclic voltammetry.The results imply that oligomers of p-phenylenediamine can effectively expand the layer spacing of GO,and the composite shows a random stacking manner.Oligomers of p-phenylenediamine,heated at 60℃ for 48 h,have the greatest effect on the modification of GO.Specific capacitance of the composite is 453 F/g,and the retention is above 98% after 600 cycles.Furthermore,a prototype supercapacitor was fabricated in a CR2032 cell case.Calculated by the active substance,the energy density of the cell is 6.8 W·h/kg,and the power density is 516.3 W/kg.And the retention is 90% of its original charging/discharging process after 1000 cycles.The results imply that graphene oxide modified by oligomers of p-phenylenediamine will have a good potential application in energy storage.

The reactions of poly(benzoquinone-1,4-diimine-N,N′-diyl-1,4-phenylene) and N,N′-di-(4-aminophenyl)benzoquinone-1,4-diimine with sulfuric acid proceeded as 1,4-addition of sulfuric acid and water to quinonediimine groups. Relative rates of these reactions depend on concentration of sulfuric acid. Electrical conductivities of both synthesized and doped with acids compounds were determined. Maximum value of conductivity 10–7 S/cm for doped polymers was achieved in case of doping level approximately 30%. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) have attracted extensive attention as precursors for the preparation of carbon-based materials due to their highly controllable composition, structure, and pore size distribution. However, there are few reports of MOFs using p-phenylenediamine (pPD) as the organic ligand. In this work, we report the preparation of a bimetallic MOF (CoCu-pPD) with pPD as the organic ligand, and its derived hollow carbon spheres (BMHCS). CoCu-pPD exhibits a hollow spherical structure assembled by nanosheets. BMHCS inherits the unique hollow spherical structure of CoCu-pPD, which also shows a large specific surface area and heteroatom doping. When using as the anode of sodium-ion batteries (SIBs), BMHCS exhibits excellent cycling stability (the capacity of 306 mA h g−1 after 300 cycles at a current density of 1 A g−1 and the capacity retention rate of 90%) and rate capability (the sodium storage capacity of 240 mA h g−1 at 5 A g−1). This work not only provides a strategy for the preparation of pPD-based bimetallic-MOFs, but also enhances the thermal stability of the pPD-based MOFs. In addition, this work also offers a new case for the morphology control of assembled carbon materials and has achieved excellent performance in the field of SIBs.

Aluminum is a kind of metal that we often encounter. It can also be absorbed by the human body invisibly and will affect our bodies to a certain extent, e.g., by causing symptoms associated with Alzheimer’s disease. Therefore, the detection of aluminum is particularly important. The methods to detect metal ions include precipitation methods and electrochemical methods, which are cumbersome and costly. Fluorescence detection is a fast and sensitive method with a low cost and non-toxicity. Traditional fluorescent nanomaterials have a high cost, high toxicity, and cause harm to the human body. Graphene quantum dots are a new type of fluorescent nanomaterials with a low cost and non-toxicity that can compensate for the defects of traditional fluorescent nanomaterials. In this paper, c-GQDs and o-GQDs with good performance were prepared by a bottom-up hydrothermal method using o-phenylenediamine as a precursor and citric acid or boric acid as modulators. They have very good optical properties: o-GQDs exhibit orange fluorescence under UV irradiation, while c-GQDs exhibits cyan fluorescence. Then, different metal ions were used for ion detection, and it was found that Al3+ had a good quenching effect on the fluorescence of the o-GQDs. The reason for this phenomenon may be related to the strong binding of Al3+ ions to the N and O functional groups of the o-GQDs and the rapid chelation kinetics. During the chelation process, the separation of o-GQDs’ photoexcited electron hole pairs leads to their rapid electron transfer to Al3+, in turn leading to the occurrence of a fluorescence-quenching phenomenon. In addition, there was a good linear relationship between the concentration of the Al3+ ions and the fluorescence intensity, and the correlation coefficient of the linear regression equation was 0.9937. This illustrates the potential for the wide application of GQDs in sensing systems, while also demonstrating that Al3+ sensors can be used to detect Al3+ ions.

Background: A European pediatric patch test series was suggested recently. Objectives: To evaluate the patch test results in children (<10-years-old) and adolescents (10- to 18-years-old) in Turkey, focusing on the clinical/occupational relevance and the diagnostic value of the recently suggested series. Patients and Methods: A retrospective cohort study on 317 consecutively patch tested patients ≤18 years of age, between 1996 and 2017. Results: The contact sensitization rate was 46.1%. Allergic contact dermatitis (ACD) was diagnosed in 30.9%, comprising non-occupational (84.7%) and occupational (15.3%) ACD. Nickel was the leading allergen in almost every age group. Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) was the clinically most relevant allergen, followed by p-phenylenediamine (PPD), ammonium persulfate, fragrance mix I, nickel sulfate, and mercury/mercury(II)amidochloride. Occupational ACD was most frequently seen in hairdresser apprentices (adolescents only) who were sensitized with PPD ± ammonium persulfate. ACD from MCI/MI increased to 5-fold, ammonium persulfate and mercurial compounds to 2-fold, and PPD to 1.7-fold after 2007. Almost one third of patients would be missed by testing only with the recommended allergens. Conclusions: For patch testing in Turkish children and adolescents, we suggest additionally testing with ammonium persulfate, mercury/mercury(II)amidochloride, toluenesulfonamide formaldehyde resin, and polyethylene glycol, the latter as a marker for nitrofurazone allergy, in appropriate patients. [ABSTRACT FROM AUTHOR]

Background: N‐acetyltransferase 1 (NAT1) is an enzyme expressed among others in keratinocytes in human skin. NAT1 is important in the biotransformation of aromatic amines, an important example being p‐phenylenediamine (PPD), a hair dye molecule. Unoxidized PPD penetrates the skin and is N‐acetylated by NAT1. Objectives: To investigate in detail the expression pattern of NAT1 in human skin. Materials and Methods: Cryosections obtained from healthy human skin were stained for NAT1 and expression patterns were observed. NAT1 double stainings were performed with antibodies against different cellular organelles to determine expression patterns. Result: A speckled, granular expression of NAT1 was seen predominantly in the stratum basale. NAT1 was expressed in a cytoplasmic pattern, perinuclear, and in the nucleus. No co‐localisation was seen with the selected cellular organelles. Local differences in NAT1 expression patterns were observed between donors and between different biopsies obtained from the same donor. Conclusions: NAT1 is expressed predominantly in the stratum basale and can be found in the cytoplasm, nucleus, and perinuclear in human skin. Further studies should be performed to investigate expression of NAT1 in a larger sample size. [ABSTRACT FROM AUTHOR]

VSe 2 is a promising anode material for Li-ion batteries (LIBs) due to its unique layered structure, and its metallic properties. However, further exploration to investigate the lithium storage performance of VSe 2 is limited by the synthesis difficulty of pure VSe 2. In this work, a novel nitrogen-doped carbon modified VSe 2 obtained by using p -phenylenediamine as the reducing agent is reported. This material delivers a reversible capacity of 738.25 mA h g−1 at 100 mA g−1 and after 50 cycles, it retains 772.15 mA h g−1. Using p -phenylenediamine as a reducing agent to obtain VSe 2 is demonstrated for the first time, and p -phenylenediamine also provides carbon and nitrogen sources for the heteroatom modification of VSe 2. This modification of nitrogen-doped carbon facilitates the generation of new active sites, and improve charge transfer. First-principle calculations show that the diffusion barrier for the Li + migration within the VSe 2 layers is low. The ex-situ X-ray diffraction (XRD) results verify that VSe 2 stores lithium through intercalation and conversion reactions. This work may provide a new solution for synthesizing high-performance transition metal dichalcogenide electrode materials. • The VSe 2 /C–N prepared using p -phenylenediamine as the reductant is first reported. • The p -phenylenediamine also provides C and N sources. • The obtained electrode achieves decent rate performance. • The Li + storage mechanism is the intercalation followed by the conversion. • The Li + diffusion barrier at the surface of VSe 2 is lower. [ABSTRACT FROM AUTHOR]

• The compatibility of different redox species with ZIF-67 electrodes was studied. • K₄[Fe(CN)₆], p-phenylenediamine (PPD), and KI were studied as active redox species. • The structure of ZIF-67 is decomposed at high potentials in an alkaline medium. • Ferrocyanides and halides promote large increases in capacitance but limit cycling. • PPD operates at low potential and promotes the greatest capacitance retention. The zeolitic imidazolate framework-67 (ZIF-67) is an attractive material as electrodes for energy storage applications due to its scalability, and high surface area. Although, its low electrical conductivity limits the specific capacitance and rate capabilities, properties which can be significantly increased when redox electrolytes are employed. Furthermore, the successful application of ZIF-67 electrodes depends on their cyclic stability. However, this material undergoes decomposition in alkaline electrolyte, which is the most commonly employed electrolyte in previously published studies, but this effect has not been taken into account. In this study the capacitance, efficiencies and stability of ZIF-67 electrodes was studied in conventional electrolyte (KOH) and with the addition of three different redox species: p -phenylenediamine (PPD), potassium hexacyanoferrate (II), and potassium iodide. Our results reveal that the addition of ferrocyanide and halides promote the greatest increases in capacitance, but their high oxidation potentials limit capacitance retention to 42% (10,000 cycles). With a lower formal potential, the use of PPD allows retentions of more than 80%. To the best of our knowledge, this is the first study that demonstrates the impact of formal potentials in the performance of ZIF-67 electrodes, highlighting the importance of a judicious selection of electrolytes to comprise this electrode. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: Scalp conditions are often multifactorial.Objective: To characterize patients with scalp involvement and patch-testing outcomes.Methods: Retrospective cross-sectional analysis of North American Contact Dermatitis Group data (1996-2016). Study groups included patients with scalp involvement (≤3 anatomic sites coded) with or without additional sites.Results: A total of 4.8% of patients (2331/48,753) had scalp identified as 1 of up to 3 affected anatomic sites. Approximately one-third of "scalp-only" individuals had a specific primary diagnosis of allergic contact dermatitis (38.6%), followed by seborrheic dermatitis (17.2%) and irritant contact dermatitis (9.3%). When adjacent anatomic sites were affected, allergic contact dermatitis was more frequently identified as the primary diagnosis (>50%). The top 5 currently clinically relevant allergens in scalp-only patients were p-phenylenediamine, fragrance mix I, nickel sulfate, balsam of Peru, and cinnamic aldehyde. Methylisothiazolinone sensitivity was notable when adjacent anatomic sites were involved. The top 3 specifically identified sources for scalp-only allergens were hair dyes, shampoo/conditioners, and consumer items (eg, hair appliances, glasses).Limitations: Tertiary referral population.Conclusion: Isolated scalp involvement was less likely to be associated with allergic contact dermatitis than when adjacent anatomic sites were involved. Overlap with multiple diagnoses was frequent, including seborrheic dermatitis, irritant dermatitis, other dermatoses, or all 3. p-Phenylenediamine was the most common allergen. [ABSTRACT FROM AUTHOR]

An Ag nanoparticles (NPs) layer was synthesized on Ag sheet by alloying/electrochemical dealloying method: X-ray diffraction confirmed that the new Ag phase appeared after removing Ga from Ag-Ga alloy, and scanning electron microscopy examination showed that the prepared Ag layer had a NPS structure. The fine microstructure of silver resulted in significant SERS enhancement effect, while the NPs layer was used as the SERS substrate: when the prepared NPs layer was used as a SERS substrate to detect p-phenylenediamine (PPD), it exhibited a strong SERS peak at 1590 cm−1. The result revealed that the intensity of SERS peaks was linear to the logarithm of PPD concentration in the range from 10−16 mol L−1 to 10−12 mol L−1 and the detection limit was 1.0 × 10−17 mol L−1. [ABSTRACT FROM AUTHOR]

Alpha-hemolysin (Hla) is a major virulence factor secreted by Staphylococcus aureus (S. aureus) , which can lyse a variety of mammalian cells and help bacteria evade the host immune system or antibiotics, posing a safety hazard to human health. Therefore, it is critical to establish a quick-responsive and sensitive method for Hla detection to ensure food safety. In this work, a dual-mode immunoassay was developed with both colorimetric and fluorescent readouts for discriminative detection of Hla. The proposed sensing system consists of p-phenylenediamine (PPD) and fluorescein, where fluorescein functions as a fluorescent reporter, and PPD serves a dual function as a colorimetric reporter and fluorescence quencher. Subsequently, the reaction system of this method was optimized, and the detection limit, sensitivity, and specificity were evaluated. Under optimal conditions, the proposed method possesses excellent analytical performance in the range from 0.5 to 500 ng/mL with a limit of detection as low as 0.5 ng/mL. Noteworthy, this method was successfully employed for the detection of Hla in milk with good selectivity and high accuracy. Overall, the dual-mode immunoassay provides a superior platform for the on-site, quantitative, and accurate detection of Hla in food samples.

A novel method was developed for the sensitive and visual detection of p-phenylenediamine (PPD) via immobilizing the target specie PPD on dialdehyde cellulose membrane (DCM) followed by the reaction with salicylaldehyde. The obtained solid fluorescent membrane (S-PPD-DCM) emitted yellow fluorescence under 365 nm UV light. DCM was not only used as a solid matrix but also played a vital role in the enrichment of PPD. Experimental variables influencing the fluorescence signal were investigated and optimized. Under the optimum conditions, a detection limit of 5.35 μg L−1 was obtained and two linear ranges were observed at 10–100 and 100–1000 μg L−1, respectively. Moreover, the fluorescence of the resultant membrane can still be visualized by naked eye when PPD concentration was 50 μg L−1. The detection of PPD was hardly affected by the coexistence of 1 mg L−1 of o-phenylenediamine, m-phenylenediamine or p henylamine , exhibiting good selectivity. The developed method involved in a two-step Schiff base reaction and enhanced the fluorescence emission via blocking nonradiative intramolecular rotation decay of the excited molecules. It was applied to determine the PPD in spiked hair dye with satisfactory results. Image 1 • A novel method was developed for the sensitive and visual detection of PPD. • DCM as a solid matrix played a vital role in the enrichment of PPD. • The proposed method gave two linear ranges at 0.01–0.1 and 0.1–1 mg L−1, respectively. • The detection limit of PPD was calculated to be 5.35 μg L−1. • Detection mechanism was involved in two-step Schiff base reaction and AIE effect. [ABSTRACT FROM AUTHOR]

Background: The textile dye mix (TDM) 6.6% pet. contains Disperse Blue (DB) 35, Disperse Yellow 3, Disperse Orange (DO) 1 and 3, Disperse Red 1 and 17, and DB 106 and 124. The most frequent allergen in TDM‐positive patients is DO 3. Around 85% of p‐phenylenediamine (PPD)‐allergic dermatitis patients have shown positive patch test reactions to DO 3. There has been a discussion to exclude DO 3 from TDM 6.6% because of frequent, strong reactions to TDM 6.6% and PPD. Objectives: To study if DO 3 can be omitted from a TDM. Methods: Patch tests were performed on 2250 dermatitis patients with TDM 6.6%, TDM 5.6% pet., TDM 7.0% pet., and PPD 1.0% pet.; 122 patients were also patch tested with DO 3 1.0% pet. Results: Among the 2250 patients patch tested, contact allergy prevalence to TDM 6.6% was 2.4%, to TDM 5.6% 1.8%, and to TDM 7.0% 2.0%. Of the 54 TDM 6.6%‐positive patients, 55.6% reacted to PPD; as much as 42.2% of PPD‐allergic women and 50% of PPD‐allergic men reacted to TDM 6.6%. Of the 17 DO 3‐positive patients, 94.1% showed a positive reaction to PPD. Conclusion: Results indicate that DO 3 can probably be omitted from TDM, but patch testing with TDM 6.6%, TDM 7.0%, DO 3 1.0%, and PPD 1.0% simultaneously is needed to finally decide whether it is possible or not. [ABSTRACT FROM AUTHOR]

Condensation of p-phenylenediamine and glyoxal at a molar ratio of 1: 1 made it possible to synthesize a new polyimine with chelating ability. The complexation of this polyimine with transition metals was studied and the composition and structure of the complexes obtained were explored by means of IR, electron spectroscopy, EPR, derivatography, and elemental analysis. [ABSTRACT FROM AUTHOR]

Background: Oxidative hair dyes are an important source of chemical exposure and a major risk factor for the development of occupational and non‐occupational allergic contact dermatitis (ACD) worldwide. Objective: To identify the frequency of common allergens associated with occupational and non‐occupational ACD to hair dyes during the last 10 years, in Greece. Methods: We retrospectively reviewed the medical records of patients with suspected ACD to hair dyes from 2010–2019. All patients with patch‐test‐confirmed ACD to hair dyes were evaluated. Results: Out of 501 patients with suspected ACD to hair dyes, 362 had at least one positive reaction to hair dye allergens (62.4% were customers and 37.6% were hairdressers). The mean age of customers and hairdressers was 43.8 years and 30.8 years, respectively. Of the customers, 58.9% were exposed to dyes for >10 years and 61% of hairdressers for <5 years. The most common site of ACD among customers was the scalp (85%) and among hairdressers the hands (90%). p‐Phenylenediamine (PPD) was the most common contact allergen (52.2%), followed by toluene‐2,5‐diamine, p‐aminophenol, m‐aminophenol, and ammonium persulfate. Conclusions: Sensitization prevalences for PPD and cross‐reacting allergens have increased in Greece during the last decade, regardless of occupational or non‐occupational exposure to hair dyes. [ABSTRACT FROM AUTHOR]

• Polymerization of p -phenylenediamine using chemical oxidative polymerization. • Environmentally friendly materials, Eggshell ground and nano (ESG, ESN), carbon nanotube (CNT) and eggshell/carbon nanotube (ESG/CNT, ESN/CNT) were used to prepare nanocomposites of poly (p -phenylenediamine). • The electrical conductivity and thermal stability were studied before and after adding the friendly materials. Eggshell is a bio-friendly substance containing by weight of 95% CaCO 3 and 5% the oxides (Mn, Si, Al, Fe, Cr, Cu and Ca) and organic substances. The oxidation was used to prepare the poly(p -phenylenediamine) in the presence of potassium persulphate as an oxidant. Poly (p -phenylenediamine) and their nanocomposites with nano eggshell (ESN), carbon nanotube (CNT), and nano eggshell/carbon nanotube were prepared and compared with ground eggshell (ESG). All prepared samples were confirmed via Fourier transforms infrared spectroscopy in addition to Raman spectra. The morphology has been studied by transmission electron microscopy. The thermal stability of the synthesized polymer nanocomposites was evaluated via thermogravimetric analyzer, the results proved that the addition of ESN and ESG to CNT gives better thermal stability than each compound. The addition of (2 wt%) 0.04 gm ESN + CNTs improved the thermal stability of polymer than (1 wt%) 0.02 gm ESN + CNTs. The electrical conductivity properties were studied, the results showed efficiency in the improvement of electrical properties σ = 10−5 ohm−1.cm−1, which form a better composite with higher conductivity, so it can be used as a semiconductor. [ABSTRACT FROM AUTHOR]

Supercapacitors are considered as one of the most efficient and reliable approaches to fulfill the specifications of the energy storage devices, owing to high-efficiency storage of energy, which makes supercapacitive electrode materials provoke large curiosity. In this work, we report the electropolymerization of poly(p-phenylenediamine) (PpPD) films on lightweight and inexpensive flexible carbon fiber fabrics by potentiostatic technique. The ladder structure of the electrochemically prepared PpPD was examined by Fourier transform infrared spectroscopy (FTIR). The surface characteristics and elemental composition studies were performed through field-emission scanning electron microscope (FESEM) and energy-dispersive X-ray spectroscopy (EDS), which confirmed the polymerization on the carbon fabrics. The electrochemical behavior of the fabricated supercapacitors was investigated by electrochemical analysis including cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The electrodes presented a good capacitive retention in a sweep rate range between 5 and 100 mV s−1 using cyclic voltammetry. The coated electrode exhibited good electrochemical property with a high specific capacitance of 80 F g−1 at the current density of 1 A g−1. The high electrochemical performance is associated to the outstanding conductivity, high electrochemical stability, and superior flexibility of the carbon fiber fabrics. The accomplishment of such superior performance, lightweight, and mechanically flexible supercapacitor can stimulate the use in energy storage applications and wearable electronics. [ABSTRACT FROM AUTHOR]