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An extreme dependence of the softening temperature of polycomplexes of p-phenylenediamine and low-molecular-weight polycondensation products of boric acid on the ratio thereof is revealed. The stoichiometric ratio of the BA/ p-PDA complex is 75/25 wt %, which corresponds to a molar ratio of BA trimer/ p-PDA = 1: 1. At a higher content of the amine, the softening temperature of the polycomplex decreases sharply, from 250 to 60°C, which is explained by the complexation of boric acid with the amine, a factor that prevents its dehydration. The energies of the intermolecular interaction between the components of the complex in a vacuum are calculated, and quantum-chemical calculations of the energy of interaction between the components of the complex are performed. The resulting products exhibit paramagnetic and fluorescent properties. [ABSTRACT FROM AUTHOR]

A rapid colorimetric method for detection of p-phenylenediamine ( PPD) in various biological samples is developed. The o-cresol test for acetaminophen detection has been modified to detect PPD in blood, urine, gastric contents, and liver. After precipitating protein with trichloroacetic acid solution (2 mL, 10% w/v), biological specimens were required to convert PPD metabolites to PPD by acid hydrolysis. Finally, o-cresol solution (1 mL, 1% w/v), hydrogen peroxide (200 μL, 3%v/v), and concentrated ammonium hydroxide (0.5 mL) were added in the biological samples. The presence of PPD was indicated by formation of violet color which was turned to bluish green color within 10-15 min. The limit of detection was found to be 2 mg/L in blood, urine, and gastric contents and 2 mg/Kg in liver. This method is also free from any potential interference by p-aminophenol, acetaminophen, and other amine drugs under test conditions. This method was successfully employed to thirteen fatal cases of PPD poisoning. [ABSTRACT FROM AUTHOR]

ABSTRACT In this thesis, two novel porous hyperbranched poly(1,3,5-tris(4-carboxyphenyl) benzene p-phenylenediamine) amides with different terminal functional groups are synthesized through an A2 + B3 approach using 1,3,5-tri(4-carboxyl phenyl) benzene (H3BTB) and p-phenylenediamine as raw material, N-methyl-pyrrolidone as solvent, triphenyl phosphite and pyridine as dehydrating agent, by means of regulating the mole ratio of the monomers. The chemical structures of the prepared hyperbranched polymers are characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance (1H-NMR and 13C-NMR) analysis. These two polymers can be soluble in dimethyl sulfoxide (DMSO) and N, N-dimethyl formamide (DMF). Their DMSO solutions exhibit strong blue fluorescence, especially for the amino terminated polymer HP-NH2. While in DMF solution, the two polymers emit strong green fluorescence. These two polymers are porous polymers with the Brunauer−Emmett−Teller surface areas of 4.53 and 24.52 m2/g for HP-COOH and HP-NH2, respectively. They are potential useful in the areas of storage, separation, catalysis, and light emitting. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44505. [ABSTRACT FROM AUTHOR]

Background Contact allergy to linalool hydroperoxides (Lin- OOHs) and limonene hydroperoxides (Lim- OOHs) is common. Similarly to what occurs with the terpene hydroperoxides, reactive intermediates formed from p-phenylenediamine ( PPD) can cause oxidative modifications of tryptophan residues on proteins in mechanistic studies. Objectives To test the hypothesis that patients sensitized to PPD are at increased risk of concomitant reactivity to either of the terpene hydroperoxides, owing to a 'common pathway' of skin protein oxidation. Methods A database study of consecutively patch tested eczema patients (n = 3843) from 2012 to 2015, tested concomitantly with PPD, Lim- OOHs and Lin- OOHs, was performed. Associations were examined by level of concordance and odds ratios ( ORs) adjusted for age, sex, and contact allergy to fragrance mix I and fragrance mix II. Results Concomitant reactions to PPD were seen in 2.2% of Lim- OOH-positive patients and in 4.9% of Lin- OOH-positive patients. Neither proportion was higher than expected by chance. No association existed between PPD and Lim- OOH patch test reactivity. In a multiple logistic regression analysis, PPD allergy was associated with an insignificantly increased risk ( OR 2.11, 95% CI:0.92-4.80) of a positive patch test reaction to Lin- OOHs. Conclusions PPD sensitization cannot explain the high rates of sensitization to Lin- OOHs and/or Lim- OOHs. Contact allergy to oxidized linalool is more strongly associated with fragrance allergy than with PPD allergy. [ABSTRACT FROM AUTHOR]

Background Cross-reactions and co-sensitizations are of great importance in understanding contact allergy and exposure sources. Objectives To investigate common cross-reactions and co-sensitizations in p -phenylenediamine ( PPD)-sensitized and toluene-2,5-diamine ( TDA)-sensitized individuals. Methods From our patch test population, 8036 patients patch tested with the European baseline series were extracted. Readings had to be performed at least on day 3 according to ICDRG guidelines. Results Two hundred and fifty-one patients were sensitized to PPD and/or TDA; 231 patients were sensitized to PPD, and 109 to TDA. Significant differences were observed regarding the strengths of patch test reactions to PPD and number of cross-reactions. For TDA, a difference was found between all reaction strengths, except between + and ++ strengths. PPD-sensitized individuals were more likely to be sensitized to carba mix, cobalt chloride, colophonium, p- tert-butyl phenolformaldehyde resin, paraben mix, and methylisothiazolinone. TDA-sensitized individuals were more often sensitized to carba mix. Conclusions Cross-reactivity was commonly found among individuals sensitized to PPD or TDA, and was strongly related to the strength of the patch test reaction. Regarding co-sensitizations, a frequently appearing or common exposure source could not be determined. However, modification of the allergen by, for example, the skin microbiota may have caused the formation of molecules that are, for the human immune system, indistinguishable from PPD. [ABSTRACT FROM AUTHOR]

Background Henna has a very low allergic potential, and severe allergenic contact dermatitis is mainly caused by p-phenylenediamine ( PPD), which is added to temporary black 'henna tattoos', and potentially also by some heavy metals. Objective To determine the presence of, and quantify, Lawsone, PPD and heavy metal contaminants (cobalt, nickel, lead, and chromium) in commercial temporary black henna tattoo mixtures (n = 25) sold in Turkey. Methods Lawsone and PPD concentrations were analysed with high-performance liquid chromatography, and heavy metal quantification was performed with inductively coupled plasma mass spectrometry. Results PPD was found in all 25 black henna tattoo samples purchased from tattoo shops; levels varied between 3.37% and 51.6%. Lawsone was detected (0.002-88.2%) in 21 of the 25 temporary black henna tattoo samples analysed. Heavy metal contaminant levels were 0.44-3.11 ppm for Co, 1.13-2.20 ppm for Ni, 1.59-17.7 ppm for Pb, and 35.0-76.9 ppm for Cr. Conclusions Our results suggest that commercial temporary black henna mixtures containing PPD levels up to 51.6% pose a risk of contact sensitization and severe allergic contact dermatitis among users. It is important to identify both the additives and metallic contaminants of black henna tattoo products; the significance of metal contaminants has still to be assessed. [ABSTRACT FROM AUTHOR]

2-Aryl isatogens and their 3-imino derivatives have been extensively studied but to date there have been no reported variants carrying pyrrolyl substituents at the 2-position. This study describes the unexpected synthesis of two novel 3-imino-2-(pyrrol-2-yl) isatogen derivatives upon attempted amide couplings with (E)- or (Z)-3-(3,5-dimethyl-1H-pyrrol-2-yl)-2-(2-nitrophenyl)acrylic acids andp-phenylenediamines in the presence of uronium-based coupling reagents. Imine hydrolysis of one derivative under mild acid conditions afforded a 2-pyrrolyl isatogen in high yield. The compound showed potent in vitro antiplasmodial activity againstPlasmodium falciparum. [ABSTRACT FROM PUBLISHER]

• The semiconducting polymer with visible light was designed for photocatalysis. • The sensor exhibited high performance for p-phenylenediamine detection. • The photoelectrochemical sensor could be used in complex matrix. Herein, this paper reports a simple and label-free photoelectrochemical (PEC) sensor based on the organic semiconducting conjugated polymer-polyfluorene derivative, poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(6-{4-ethyl-piperazin-1-yl}-2-phenyl-benzo{de}isoquinoline-1,3-dione)] (PFNA). The PFNA was designed and obtained the lowest unoccupied molecular orbital (LUMO)/highest occupied molecular orbital (HOMO) values via spectral characterizations. The PFNA modified electrode produced a stable and enhanced photocurrent signal under white light irradiation at a bias of −0.1 V in phosphate buffer solution. A sensitive increment of the photocurrent was observed with the addition of p -phenylenediamine (p -PD). A possible mechanism for this photoelectrochemical process including the photoexcitation of the polymer, electron injection from polymer toward the electrode, and the hole-scavenging process by the reductants were studied. The π bond in the polymer might facilitate the photoelectrochemical process owing to the enhanced electronic coupling between the polymer and the reductants. A PEC analysis on p -PD has been carried out to evaluate the photoelectrochemical performances of the modified electrode, which presents the wide linear ranges of 0.2–400 μM, with a lower detection limit of 0.13 μM. This work reports the PEC performance of organic semiconducting conjugated polymer-polyfluorene derivative, which would promote more efficient photoelectrochemical design of sensors and devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • A "turn off" fluorescence and colorimetric dual-reading sensor detection of glucose and H 2 O 2 was constructed. • A strategy for detection glucose based on IFE without distance restriction between UCNPs and accepters. • Compared with other chromogenic substrates, the water solubility and stability of PPD were relatively better. • The LODs of H 2 O 2 and glucose were 0.32 and 0.83 μmol/L, which were lower than reported in the literature. • The results of detection glucose in serum by this method were consistent with those of other methods. Here, the inner filter effect (IFE) was applied to construct a "turn off" mode up-conversion fluorescence and colorimetric dual-reading detection platform consisting of the chromogenic substance p-phenylenediamine (PPD) and NaYF 4 :Yb/Er@NaYF 4 core–shell up-conversion nanoparticles (UCNPs) for the detection of glucose and hydrogen peroxide (H 2 O 2) with high sensitivity and selectivity. In this strategy, hydrogen peroxide is produced in the process of glucose oxidation by catalyzing glucose oxidase (GOx). PPD is oxidized by H 2 O 2 under the action of horseradish peroxidase (HRP), resulting in the transformation into its oxidation product PPDox, whose absorption peak coincides with the emission peak of UCNP at 540 nm, which can significantly quench the fluorescence of UCNP. The quenching efficiency is related to PPDox production, so the relationship between the glucose content and the fluorescence changes of UCNP can be established to realize the sensitive detection of glucose. UCNPs modified by –COOH and the oxidation product of PPD were negatively charged, which increased the distance between donor and recipient due to electrostatic repulsion. It was not conducive to the occurrence of distance-dependent fluorescence resonance energy transfer (FRET), which was also verified by fluorescence lifetime test. Under the optimal experimental conditions, the linear ranges of hydrogen peroxide and glucose were 2.5 ∼ 50 and 5 ∼ 80 μmol/L with the detection limit (LOD) of 0.32 and 0.83 μmol/L, respectively, which were lower than of some reported approaches. Furthermore, the system could be applied to the detection of glucose in actual serum sample and the results were consistency of commercial glucose meters which indicated that the protocol was reliable and potential applications for clinical diagnosis. [ABSTRACT FROM AUTHOR]

Background: Exposure to arsenic (As) or  p ‑phenylenediamine (PPD) can lead to dysfunction, or even cancer, in various types of organs, including the urinary bladder, yet the underlying mechanisms remain unclear. Aquaporins (AQPs) are widely expressed small water channel proteins that provide the major route for the transport of water and other small molecules across plasma membranes in diverse cell types. Altered expression of AQPs has been associated with pathologies in all major organs, including the urinary bladder., Objective: The present in vitro study was performed as a first step towards exploring the possible involvement of AQPs in As- and PPD‑induced bladder diseases., Methods: An immortalized normal human urothelial cell line was employed. Cells were exposed to different concentrations of sodium arsenate (0‑20 μM) or PPD (0‑200 μM) for 48 h. Cell viability was subsequently assessed. The mRNA and protein expression levels of AQPs (specifically, AQP3, 4, 7, 9, and 11) were analyzed using reverse transcription‑quantitative polymerase chain reaction and Western blot analyses, respectively., Results: The viability of the cells was decreased in a concentration-dependent manner upon exposure to arsenate. The mRNA and protein expression levels of AQP3, 4, 7, and 9 were substantially reduced, whereas the expression of AQP11 was largely unchanged. As for the experiments with PPD, treatment with increasing concentrations of PPD induced a gradual decrease in cell viability. The mRNA and protein expression levels of AQP3, 4, and 11 were generally unaltered; however, a marked reduction in the expression levels of AQP7 was observed, contrasting with a gradual concentration-dependent decrease in the expression of AQP9., Conclusion: The importance of the differential expression profiles of the AQPs induced by arsenate and PPD requires further investigation; nevertheless, the findings of the present study suggest that AQPs have a role in As‑ and PPD‑induced bladder diseases., Competing Interests: The authors have declared financial relationships, which are detailed in the next section., (Copyright © 2023, Wu et al.)

Cases of poisoning by p-phenylenediamine (PPD) are detected sporadically. Recently an article on the development and validation of an LC-MS/MS method for the detection of PPD and its metabolites, N-acetyl- p-phenylenediamine (MAPPD) and N, N-diacetyl- p-phenylenediamine (DAPPD) in blood was published. In the current study this method for detection of these compounds was validated and applied to urine samples. The analytes were extracted from urine samples with methylene chloride and ammonium hydroxide as alkaline medium. Detection was performed by LC-MS/MS using electrospray positive ionization under multiple reaction-monitoring mode. Calibration curves were linear in the range 5-2000 ng/mL for all analytes. Intra- and inter-assay imprecisions were within 1.58-9.52 and 5.43-9.45%, respectively, for PPD, MAPPD and DAPPD. Inter-assay accuracies were within −7.43 and 7.36 for all compounds. The lower limit of quantification was 5 ng/mL for all analytes. The method, which complies with the validation criteria, was successfully applied to the analysis of PPD, MAPPD and DAPPD in human urine samples collected from clinical and postmortem cases. [ABSTRACT FROM AUTHOR]

The thermal stability of microporous networks of Pt nanoparticles interlinked by p-Phenylenediamine (PDA) was investigated by temperature-programmed desorption spectroscopy (TPD) and transmission electron microscopy (TEM). The detection of aniline, benzene, and NH 3 as major desorbing fragments in TPD revealed cleavage of the C-N bonds in PDA as a major route of thermally induced decomposition, probably via hydrogenolysis assisted by dehydrogenation reactions of PDA running alongside. Varying the Pt:PDA ratio in the networks demonstrated that the Pt nanoparticles catalytically promote the decomposition of their PDA links. A quantitative analysis of the TPD spectra indicated that the thermal stability of PDA strongly correlates with the number of bonds (0, 1 or 2) formed by the amino groups of an individual PDA molecule with Pt. Only the most stable PDA species appears to be of relevance for the structural stability of the nanoparticle network, as heating experiments with in situ TEM showed. The results have strong implications for the application of PDA-linked Pt nanoparticles as heterogeneous catalysts in hydrogen gas microsensors where the choice of operating temperature has to balance maximization of signal-to-noise ratio and maintenance of structural stability. An anealing step up to 450–500 K after synthesis of the catalyst is suggested in order to optimize its catalytic activity by removing PDA species that are not essential for structural stabilty. [Display omitted] • Pt nanoparticles linked by p-Phenylenediamine form microporous nanocatalyst. • Temperature-programmed desorption spectroscopy used to analyze thermal stability. • Diamine is decomposed by Pt-promoted hydrogenolysis at elevated temperature. • Diamine with two dative Pt bonds is more stable than diamine with one Pt bond. • Ligand-linked Pt nanoparticle networks in hydrogen pellistors are stable up to 450 K. [ABSTRACT FROM AUTHOR]

[Display omitted] • The positive-charged GO has been acquired to achieve the cathodic EDP. • The reduction of GO based on potential difference has been employed. • Excellent performance of common battery systems are achieved. • A versatile and innovative approach for electrode surface protection is developed. Electrode material surface protection via the two-dimensional structured graphene oxide (GO) is studied in our work for rechargeable batteries by the electrophoretic deposition (EPD). However, the large number of oxygen-containing groups on the surface and edge makes GO sheets negatively charged, which EPD can only be used for anode process. Thus, we apply p-phenylenediamine (PPD) to convert the surface of GO sheets to positive electricity and successfully achieve the cathodic EPD with modified GO. When, the cathode (eg. S, LiFePO 4) and anode (eg. Li, Si) with the newfangled GO coating layers are employed in a working battery, the GO can be transformed into reduced graphene oxide (rGO) due to the in-situ electrochemical reduction. Fortunately, the rGO coating layers are acquired on the electrode surfaces, which the stability, adhesion, corrosion resistance, impact resistance have been greatly improved compared to other coating methods. Ultimately, taking advantage of this rGO coating by EDP to simultaneously realize the coating protections of the electrodes can provide alternative strategies to optimize the properties of rechargeable batteries. [ABSTRACT FROM AUTHOR]

Paraphenylenediamine (PPD) represents the main active substance in the color of hair dyes. In Tunisia, PPD poisoning is very common, especially in rural areas where the consequences linked to this toxic substance are still unknown. In this paper, we report a case of PPD poisoning and confirm the diagnosis by a qualitative method of analysis. We discuss the clinical manifestations and study the kinetics of biological parameters during the monitoring of the poisoning. The main complication was renal failure and the treatment was basically symptomatic.

Abstrat In this work, a novel sandwich-structured graphene-based composite (PPD-GO) was prepared. The graphene-based composite was prepared by amination of graphene oxide (GO) with p -phenylenediamine (PPD) with the aid of the coupling reagents. And PPD was introduced into the interlayers of graphene nanosheets. The morphology, composition, and grafted functional groups of the composite were investigated by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. And PPD-GO was used as a highly efficient adsorbent for removal of Congo red from used from aqueous solutions. The whole adsorption process was studied in depth and elucidated systematically. A maximum Congo red adsorption capacity of 892.8 mg/g was obtained for PPD-GO composite at an initial temperature of 298 K and pH of 3.0. The second-order kinetic equation could well describe the sorption kinetics. The equilibrium data were perfectly fitted by the Langmuir isotherm. The thermodynamic analysis indicated that the adsorption of Congo red onto the PPD-GO composite was a spontaneous and endothermic process. [ABSTRACT FROM AUTHOR]

In this present study, biodiesel is a cleaner burning alternative fuel to the Neat diesel fuel. However, several studies are pointed out that increase in NOx emission for biodiesel when compared with the Neat dieselfuel. The aim ofthe present study is to analyze the effect of antioxidant (p-phenylenediamine) on engine emissions of a Diesel engine fuelled with methyl ester of annona oil. The antioxidant is mixed in various concentrations (0.010 to 0.040% (w/w)) with methyl ester of annona oil. Result shows that antioxidant additive mixture (MEAO + P200) is effective in control of NOx and HC emission of methyl ester of annona oil fuelled engine without doing any engine modification. [ABSTRACT FROM AUTHOR]

The whole molecule of the title compound, C32H34N2O2, is generated by inversion symmetry; the central benzene ring being situated about the crystallographic inversion center. The aromatic ring of the julolidine moiety is inclined to the central benzene ring by 33.70 (12)°. There are two intramolecular O--H...N hydrogen bonds in the molecule, generating S(6) ring motifs. The conformation about the C＝N bonds is E. The fused non-aromatic rings of the julolidine moiety adopt half-chair conformations. In the crystal, adjacent molecules are linked by pairs of C--H...π interactions, forming a ladder-like structure propagating along the a-axis direction. [ABSTRACT FROM AUTHOR]

Background Allergic contact dermatitis caused by p-phenylenediamine ( PPD) is common among all age groups and both sexes. Monitoring of prevalence and intensity of sensitization is important. Objective To evaluate contact allergy to PPD in Europe, and to compare reaction intensities in different European regions. Methods Data collected by the European Surveillance System on Contact Allergies ( ESSCA) network between 2002 and 2012 from 12 European countries were analysed regarding prevalence, grading of positive reactions to PPD, and relevance. Results A total of 99 926 PPD-positive patients from 63 departments were included for analysis. The overall (2002-2012) prevalence of PPD sensitization in Europe is ∼4%. Stratified for country, the highest overall standardized prevalence was found in Lithuania, and the lowest in Slovenia. The prevalence of PPD sensitization did not decline over the years. In the southern European countries, higher numbers of strong and extremely strong reactions were registered. The clinical relevance of PPD sensitization varied from half to three-quarters. Conclusion The prevalence of PPD sensitization has not changed over time. Strong and extremely strong patch test reactions are seen more often in the South, probably because of the higher number of PPD-containing hair dye products. [ABSTRACT FROM AUTHOR]

In this work, cross-linked graphene aerogel (CL-GA) and its composite with Fe 2 O 3 nanoparticles (NPs) were synthesized through a one-step hydrothermal procedure by using p-phenylenediamine (PPD). Structural characterizations revealed that in the preparation of the composite PPD acts as a cross-liker and provides high surface area by decreasing restacking of graphene sheets and functions as nitrogen source simultaneously. The electrochemical characteristics of the nanocomposite were investigated by cyclic voltammetry (CV), galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS) and Fast Fourier transform continues cyclic voltammetry (FFTCCV). The results show that cross-linked graphene aerogel/Fe 2 O 3 (CL-GA/Fe 2 O 3 ) nanocomposite displays enhanced supercapacitive performance, where it has capacitance of 445 at 1 A g −1 , high energy density of 63 W h Kg −1 , and 89% capacitance retention after 5000 cycles in 3 M KOH. Presence of PPD considerably improved supercapacitive performance of nanocomposite as a result it could be promising material in synthesis of efficient graphene/metal oxide-based electrode material for high performance supercapacitors. [ABSTRACT FROM AUTHOR]

Nowadays, antimicrobial N-halamine polymers and coatings are extensively studied thanks to their qualities such as effectiveness toward a broad spectrum of microorganisms and regenerability. An N-halamine organic polymer contains nitrogen-halogen covalent bonds. Its antimicrobial properties are due to the oxidizing power of the halide atoms, which are at the oxidation state + I in chloramine (>N-Cl) or bromamine (>N-Br) groups. The aim of the present work was to generate a new N-halamine coating in a two-step route. First, we have synthesized by electroreduction of in situ generated aminophenyl diazonium cations polyaminophenyl films because these films contain numerous amino functions. Electrochemical quartz crystal microbalance (EQCM) allowed us to determine the mass of the film formed by cyclic voltammetry and to estimate its thickness; the highest one is about 1 µm. Then, the second step of the process was the formation of haloamine functions into the polyaminophenyl film by substitution of H atoms of the amine functions by Br or Cl atoms. The films were observed by SEM, and their composition was determined by Energy-dispersive X-ray spectroscopy (EDS). Finally, the EQCM experiments allowed us to estimate that the N-halamine films that we have prepared contain one Cl atom or one Br atom for 4 or 4.5 phenyl groups, respectively. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A series of copolyimides were prepared by thermal imidization of poly(amic acid)s (PAAs) derived from 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3',3,4'-biphenyltetracarboxylic dianhydride (a-BPDA), p-phenylenediamine (PDA) and 4,4'-oxydialinine (4,4'-ODA) commonly used for the production of commercial polyimides. The flexible copolyimide films were obtained from that the molar ratio of s-BPDA, a-BPDA, PDA and 4,4'-ODA was 9:1:8:2 (Co-PIs-3), 8:2:9:1 (Co-PIs-5) and 8:2:8:2 (Co-PIs-6). These obtained copolyimide films were characterized by Fourier transform-infrared spectroscopy(FTIR), wide angle X-ray (WAXD), Thermogravimetric (TG), dynamic mechanical thermal analysis (DMA), thermomechanical analysis (TMA), field-emission scanning electron microscopy (FE-SEM) and mechanical properties measurement. The results showed that three copolyimides remained semi-crystalline and exhibited high glass transition temperature (Tg), high thermal stability, great ultimate tensile strength and low coefficient of thermal expansion (CTE). The Co-PIs-5 had lower crystallinity, lower CTE, greater elongation at break, higher Tg and thermal stability and the greater dense extent, compared with Co-PIs-3 and Co-PIs-6. Structure and property relations of the prepared polyimides were also briefly discussed. The results revealed that the copolymerization of s-BPDA/PDA with a small number of 4,4'-ODA/a-BPDA was a useful means for enhancing flexibility without sacrificing low CTE. [ABSTRACT FROM AUTHOR]

Background Hair dyes represent one of the most important causes of allergic contact dermatitis resulting from the use of cosmetic products. The principal causative chemistry is associated with oxidation products of p-phenylenediamine ( PPD) and closely related substances. Objectives To examine whether prior application of the antioxidant vitamin C to the skin was able to reduce the cutaneous allergic response to PPD. Methods Twenty eight volunteers with a proven history of contact allergy to PPD were recruited. Each was tested with a range of PPD doses and PPD-containing hair dye on untreated skin and skin pretreated for 10 min with a vitamin C formulation. Results Pretreatment of skin sites with vitamin C led to a reduction in the intensity, or even ablation, of the cutaneous allergic reaction to PPD in ∼75% of cases as compared with untreated skin. Conclusions The results suggest that treatment of the skin adjacent to the hair-bearing area with antioxidant could form part of a strategy to reduce the burden of cosmetic allergic contact dermatitis caused by hair dyeing. [ABSTRACT FROM AUTHOR]

Background An allergic contact reaction is accompanied by high oxidative stress in the skin. Pretreatment of the skin with antioxidative substances could reduce the elicitation reaction. Objectives To investigate, in a proof-of-principle study, whether pretreatment of the skin with the antioxidant ascorbic acid reduces the elicitation reaction to a p-phenylenediamine ( PPD)-containing hair dye in sensitized subjects. Methods Twelve subjects with contact allergy to PPD, a documented skin reaction to a hair dye simulation exposure model and a history of hair dye-related skin complaints were included in this study. Skin areas on the forearms were, in a left versus right design, exposed to an emulsion with ascorbic acid and an emulsion without ascorbic acid, and then to a 2% PPD-containing hair dye testing formulation. In addition, control areas were exposed to the emulsions and to the PPD-containing hair dye formulation without pretreatment. Skin reactions were graded on day (D)2 and D3. Results Pretreatment with ascorbic acid emulsion resulted in a reduction in the elicitation reaction in 7 of 12 subjects at D3 ( p = 0.046). No statistically significant difference was observed at D2. Conclusions Pretreatment of the skin with the antioxidant ascorbic acid had an attenuating effect on the elicitation reaction to PPD in sensitized individuals. [ABSTRACT FROM AUTHOR]

Background Hair dyes are known to contain potent contact allergens for which sensitization rates have increased over the last decade. Objective To examine the type and frequency of potent contact sensitizers labelled on hair dyes sold in metropolitan Bangkok, Thailand. Methods During the 2013-2014 study period, labelled ingredient information from home use and professional hair dye products was collected. Results Two hundred and fifty-two hair dye products were evaluated. One hundred and forty-nine products from 48 brands were domestically produced in Thailand, and 103 products were from 23 multinational brands produced in countries other than Thailand. Two hundred and fourteen of 252 (84.9%) hair dye products were found to contain strong skin sensitizers, with 118 (46.8%) being found in domestically produced products, and 96 (38.1%) being found in multinational brand products. Thirty-eight hair dye products (15.1%) were free of potent skin sensitizers. The number of domestically produced products (31, 20.8%) that were free of potent skin sensitizers was significantly higher ( p = 0.002) than the number of multinational brand products (7, 6.8%). Conclusions p- Phenylenediamine was the most prevalent potent sensitizer found among domestically produced hair dyes available on the market. Our findings indicate regional differences in hair dye allergen exposure. [ABSTRACT FROM AUTHOR]

Electroconducting hydrogels (EH) based on copoly(aniline – p-phenylenediamine) grafted to the polyacrylamide for the application as pseudo-supercapacitor's electrodes have been prepared. The influence of preparation conditions on the structure and capacitance properties of the systems were investigated: we determined the optimal amount of p-phenylenediamine to obtain the network of swollen interconnected nanofibrils inside the hydrogel which provides the formation of continuous conducting phase. Structure and morphology of the prepared samples were investigated with UV–VIS spectroscopy, scanning electron microscopy (SEM) and wide-angle X-ray diffraction (WAXD). The maximal value of capacitance was 364 F g −1 at 0.2 A g −1 . It was shown that the EH samples demonstrate the retention of 50% of their capacity at high current density 16 A g −1 . Cycle-life measurements show evidence that capacitance of EH electrodes after 1000 cycles is higher than its initial value for all prepared samples. Changes of the copolymer structure during swelling in water have been studied with WAXD. [ABSTRACT FROM AUTHOR]

The article presents the case of a 32-year-old woman with discoid lupus that was triggered by allergic contact dermatitis caused by a hair dye. She was presented at the dermatology department with itchy red inflammatory lesions in the retro-auricular area. The lesions appeared following the application of a hair dye, which she tolerated in the past.

Background Contact allergy in children is becoming increasingly recognized as a cause of eczema. The causal agents may change with time, but there are few comparative data for this age group. Objectives To compare data from the past 10 years with a similar study from the previous decade. Methods Between 2005 and 2014, 500 consecutive children who had been patch tested at Leeds Teaching Hospitals were identified, and the results were reviewed. Results Twenty-seven per cent (134 cases) of children had one or more positive patch test findings. The mean ± standard deviation age of patients with a positive test reaction was 11.9 ± 4.1 years, which was significantly higher than that of patients with a negative result (10.9 ± 4.0 years) ( p = 0.01; Mann-Whitney U-test). No significant relationship between sex and a positive patch test result was found ( p = 0.48, chi-squared). Allergy to nickel was the most frequent finding, although this accounted for 18%, rather than 33% (1995-2004), of all positive reactions. The next most common allergens included fragrance mix 1 (17%), p-phenylenediamine (16%), and methylchloroisothiazolinone/methylisothiazolinone (6%). Conclusions Although the overall incidence of contact allergy in our paediatric population is static, there has been a significant change in the allergens detected, probably as a result of changes in European legislation and cosmetic product use in children. [ABSTRACT FROM AUTHOR]

The redox-active materials based on the condensation product of cyclohexanehexone with p -phenylenediamine (PTDA) were synthesized. The effect of the reactant ratios (1: n, n = 1, 2, 3) on the morphology and electrochemical properties of the resulting polymers PTDA1-PTDA3 was analyzed. In the case of PTDA3, a regular network crosslinked by C N-C bonds is formed resulting in a significant increase in the practical capacity of this material from 160 to 285 mAh g−1 corresponding to a three-electron redox process. Quantum-chemical modeling was performed to clarify the peculiarities of the lithiation mechanism. It is shown that the best sites for lithium cation coordination are adjacent oxygen and nitrogen atoms or two nitrogen atoms. For all polymer structures, sequential redox lithiation-delithiation processes have been established. [Display omitted] • Redox-active polymers were synthesized from triquinoyl and p -phenylenediamine. • Material composition, structure and morphology is controlled by the reagent ratios. • Using an excess of amine produced PTDA3 featuring a regular 3D network morphology. • PTDA3 enables the best battery performance with a specific capacity of 285 mAh g−1. • DFT calculations were used to model the material redox transformations in batteries. [ABSTRACT FROM AUTHOR]