Widespread use of oxidative hair dyes during the past decades has raised questions on the potential allergy reactions and their management, as well as prevention measures for both professionals and ...consumers. Allergic contact dermatitis can be elicited by various hair dye-related allergens, though the main problem remains with
-phenylenediamine and related aromatic amines. If allergy is suspected, patch testing identifies the responsible hapten. Individuals sensitized to specific permanent hair dyes substances should avoid the exposure to these chemicals, but also be aware of possible cross-sensitization to other similar compounds. Cross-reactions detected in patch-tested populations indicate that one cannot safely use alternatives, although cross-reactivity is not always clinically relevant. An open application hair dye allergy self-test is recommended by manufacturers for early detection of allergy predisposition in consumers, although the lack of standardized conditions makes the efficacy of this process doubtful. Appropriate use of hand gloves, especially nitrile, is the most efficient prevention measure for professional hand eczema. In this systematic review, we focus on cross-reactions among hair dye-related allergens and make an attempt to answer some, frequently encountered by physicians, questions, while presenting the prevalence of the hair dye-related allergens.
Molecular tweezers are artificial receptors that have an open cavity generated by two recognition units pre-organized by a spacer. Switchable molecular tweezers, using a stimuli-responsive spacer, ...are particularly appealing as prototypes of the molecular machines that combine mechanical motion and allosteric recognition properties. In this present study, the synthesis of switchable molecular tweezers composed of a central terpyridine unit substituted in 4,4″ positions by two Pt(II)-salphen complexes is reported. The terpyridine ligand can be reversibly converted upon Zn(II) coordination from a free ‘U’-shaped closed form to a coordinated ‘W’ open form. This new substitution pattern enables a reverse control of the mechanical motion compared to the previously reported 6,6″ substituted terpyridine-based tweezers. Guest binding studies with aromatic guests showed an intercalation of coronene in the cavity created by the Pt-salphen moieties in the closed conformation. The formation of 1:1 host-guest complex was investigated by a combination of NMR studies and DFT calculations.
Conventional methods using o-tolidine and N,N-diethyl-p-phenylenediamine as colorimetric reagents have been extensively applied worldwide in residual chlorine measurement for water quality and ...environmental management. Different types of interferences resulting in erroneous measurements while using colorimetry have been previously reported. In this study, we experimentally demonstrated micro-particles as interfering substances in selected inorganic (five metal oxidants) and organic (microalgae) particles. The results indicated erroneous measurements (viz. colour development) for three of the selected particles. These erroneous measurement levels were evaluated with reference to the chlorine concentration (in mg-Cl2/L, hereafter represented as mg/L) in relation to both representative colorimetric reagents in terms of the amount of particles and time variations. A novel viewpoint that filtration could be a possible solution to the erroneous measurement caused by such micro-particles was proposed.
•Micro-particles classified as interfering substances in residual chlorine measurement.•Erroneous measurement caused by selected inorganic particles was investigated.•Characteristics of erroneous measurement caused by an organic bio-particle were investigated.•Filtration proposed as a solution to erroneous measurement caused by micro-particles.
The ligand tppda has been designed and synthesized as molecular leverage for helicity control when reacted with Cd(2+) ions. The guests MeOH or DMF preferentially stabilize the P-helical isomer, ...while the guest H2O causes a helix inversion to give the M-helical isomer as the major isomer without any chiral auxiliary.
Foodborne pathogens have a substantial bearing on food safety and environmental health. The development of automated, portable and compact devices is essential for the on-site and rapid point-of-care ...testing (POCT) of bacteria. Here, this work developed a micro-automated microfluidic device for detecting bacteria, such as Escherichia coli (E. coli) O157:H7, using a seashell-like microfluidic chip (SMC) as an analysis and mixing platform. The automated device integrates a colorimetric/fluorescent system for the metabolism of copper (Cu2+) by E. coli affecting o-phenylenediamine (OPD) for concentration analysis. A smartphone was used to read the RGB data of the chip reaction reservoir to detect colorimetric and fluorescence patterns in the concentration range of 102–106 CFU mL−1. The automated device overcomes the low efficiency and tedious steps of traditional detection and enables high-precision automated detection that can be applied to POCT in the field, providing an ideal solution for broadening the application of E. coli detection.
Nitric oxide (NO) has been proven to be a key regulator in the mammalian immune response, such as the innate and adaptive immune responses to tumors. The messenger NO involves T helper cell ...differentiation and lymphocyte biofunctions. In this study, we employed N,N'-di-sec-butyl-N,N'-dinitroso-1,4-phenylenediamine as NO donor and released NO around tumor infiltrating lymphocytes in vitro by short-time blue light irradiation. The interferon-γ secretion of tumor infiltrating lymphocytes was investigated to study the functional changes caused by the accurate spatio-temporal delivery of NO. The downregulation of interferon-γ in tumor infiltrating lymphocytes after NO treatment indicates promising biological applications to potentially play a role in the treatment of autoimmune diseases. The study was approved by the Medical Ethics Committee of the Shenzhen Second People's Hospital, the First Affiliated Hospital of Shenzhen University, China (approved No. 065) on February 12, 2018.
In this paper, Au/CuS composites were fabricated by a two-step method based on a facile solvothermal approach combined with the in situ reduction. It was demonstrated that the Au/CuS composite not ...only exhibited excellent peroxidase-like catalytic activity in the oxidation of the typical peroxidases (o-phenylenediamine and diaminobenzidine), but also showed promising SERS performance with remarkable sensitivity and high reproducibility. Based on these properties, the bi-functional Au/CuS composite was employed both as a catalyst for degrading a pollutant (Rhodamine 6G) and a SERS substrate for real-time monitoring of the degradation process quantitatively.
Increasingly globally prevalent obesity and related metabolic disorders have underscored the demand for safe and natural therapeutic approaches, given the limitations of weight loss drugs and ...surgeries. This study compared the phytochemical composition and antioxidant activity of five different varieties of citrus physiological premature fruit drop (CPFD). Untargeted metabolomics was employed to identify variations in metabolites among different CPFDs, and their antilipidemic effects in vitro were assessed. The results showed that
L. '
' physiological premature fruit drop (DDPD) and
'
' physiological premature fruit drop (HYPD) exhibited higher levels of phytochemicals and stronger antioxidant activity. There were 97 differential metabolites identified in DDPD and HYPD, including phenylpropanoids, flavonoids, alkaloids, organic acids, terpenes, and lipids. Additionally, DDPD and HYPD demonstrated potential antilipidemic effects against oleic acid (OA)-induced steatosis in HepG2 hepatocytes and 3T3-L1 adipocytes. In conclusion, our findings reveal the outstanding antioxidant activity and antilipidemic effects of CPFD, indicating its potential use as a natural antioxidant and health supplement and promoting the high-value utilization of this resource.
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