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Background Lichen Planus Pigmentosus (LPP), a disorder with stubborn treatment-refractory hyperpigmentation predominantly affects the darker skin. Deep dermal pigmentary incontinence of LPP renders the condition treatment-refractory. Objectives Lack of a consistently effective depigmenting treatment protocol of inactive LPP mandates exploration of novel approaches. We analyzed the effect of six sessions of modified phenol peel on reduction of pigmentation of LPP in Indian patients. Methods The results of a retrospective analysis of the efficacy and safety of six sessions of Croton oil free phenol combination (CFPC) peel done every 3 weeks, for inactive LPP-associated hyperpigmentation in 17 patients are presented. Efficacy evaluation was done with patient-reported improvement, physician-evaluated improvement (photographic comparison of baseline and post-treatment clinical images), and pre- and posttreatment comparison of dermoscopic images using a simple scale. Results Out of 17, 5 (29%) patients sustained excellent improvement with >75% reduction of pigmentation. Overall 13 (76%) patients had moderate to excellent improvement, that is, at least 25% or more reduction in pigmentation. The patient-reported improvement, physician-graded improvement, and dermoscopic changes-all three measures showed harmonious overlap. Lightening of the background color and reduction in density and color intensity of pigmented structures was observed on dermoscopy in majority of patients. The treatment was well tolerated with no serious local/systemic adverse effects. Conclusions Modified phenol peels seem effective in reduction of hyperpigmentation of LPP. They are safe and well tolerated. Thorough priming, stringent sun protection and use of post-peel adjuvant topicals boost the peel effect and aid in maintaining the effect for up to a year.

The influence of the temperature of storage on the proceeding polycondensationof commercial resol resin solutions was analyzed and it was found that results derived from a simple gel time measurements can provide the necessary information. It could be shown that resol resin solutions can be fitted into Arrhenius like models, which allow an extrapolation of the temperature-dependent changes of the material over arbitrary temperature ranges and hence estimation of the prolongation or reduction of declared shelf-life. High-performance liquid chromatographic analyses of the content of free phenol and free formaldehyde during storage could confirm and widely explain the observations from gel time measurements.

Toe nail onychomycosis (ONM) is a common problem in elderly patients. Treatment in diabetic patients with associated comorbidities such as congestive heart failure becomes a challenge. Oral antifungals are best avoided owing to most of them being contraindicated or unsafe due to comorbidities and/or risk of drug interactions stemming from polypharmacy. Topical agents alone are not effective. Unlike isolated ONM in healthy and younger patients, ONM involving multiple nails in geriatric and diabetic patients warrants treatment as it serves as a source of recurrent tinea of the feet and other sites, and even contributes to formation of diabetic foot ulcers. Long-pulsed Nd:YAG and fractional CO2 laser (in addition to antifungals) have been reported to provide gratifying results in toe nail ONM. But high treatment cost is a major limitation. Nail peeling with glycolic acid (GA) and low-concentration croton-oil free phenol (CFP) peels have been used in different nail conditions but not specifically for ONM. We report the successful use of Black peel (a superficial-to-medium depth peel used typically for anti-acne and cosmetic indications), a combination of 50% black acetic acid, 0.5% salicylic acid, 6% tetrahydrojasmonic acid, 10% bio sulphur, and 0.1% potassium iodide, in two difficult cases with ONM of multiple nails, the rationale of use being the additional anti-fungal effects of all the peel components.

The hydroxybenzene molecules can act as hydrogen bond donors and the acetonitrile molecules as hydrogen bond acceptors. Therefore, solute-solvent hydrogen bonds are the strongest solute-solvent interactions for hydroxybenzenes in acetonitrile solutions. The current study considers adducts of hydroxybenzene molecules with explicit acetonitrile molecules to investigate these interactions. The results show that acetonitrile molecules can be H-bond acceptors both to free phenol OHs and to OHs engaged in intramolecular hydrogen bonds. They also highlight the preferred arrangements of acetonitrile molecules around the central hydroxybenzene molecule, approximating the first solvation layer. Finally, they show that the acetonitrile molecules tend to interact also with each other within the adduct, and this tendency influences their arrangements around the central hydroxybenzene molecule.

In 2021, Hawaii will permanently ban the use and sale of octinoxate-based sunscreens as studies have shown serious impacts of such UV filters on the coral reef. This ban, which could be generalized to other countries, highlights the extreme need to offer alternative UV filters that are not only effective in terms of sun protection, but also healthy with regards to human health and the environment. In this context, a wide library of p-hydroxycinnamic esters deriving from naturally occurring sinapic acid has been synthesized using a Knoevenagel&ndash, Doebner condensation. The UV filtering activities as well as the antioxidant properties of these sinapic acid esters were then investigated. The results showed promising UVB protection and antioxidant efficacy. A Structure&ndash, Activity Relationship (SAR) study on the sinapic acid esters highlighted the need of a free phenol to, as expected, observe antioxidant activity, but also to obtain a higher intensity of protection. Moreover, the nature of the ester moiety also proved to be a key structural feature for the UV absorbance, as higher steric hindrance on the ester moiety leads to more active compounds. The judicious structural design of sinapic esters thus provides promising compounds combining UV protection and antioxidant activity.

“Structural” AlMe2(bht) was found to be an integral building block of the “TMA-free” olefin polymerization cocatalyst MAO/BHT (TMA = trimethylaluminum, MAO = methylaluminoxane, BHT = 2,6-di-tert-butyl-4-methylphenol). NMR studies show that treatment of MAO/BHT with the neutral N-donor pyridine (py) leads to selective generation of neutral AlMe2(bht)(py). The reaction of MAO/BHT with 2,2'-bipyridine (bipy) generates cationic [AlMe(bht)(bipy)]+ fragments (bht = BHT phenolate), analogously to what happens when unmodified MAO is treated with bipy, causing [AlMe2(bipy)]+ formation. This suggests that the activation of an olefin polymerization precatalyst LnMX2 (X = Me or Cl) can occur via an indirect pathway involving [AlMeR]+ (R = Me or bht) transient species (rather than direct Cl/Me abstraction by the Al-cages) not only when unmodified MAO is exploited but also in the case of “TMA-free” BHT-modified MAO. The high chemoselectivity of py for neutral Al adducts however presents a distinct difference to unmodified MAO. These observations indicate that a) “structural” TMA is converted into “structural” AlMe2(bht) upon reaction of MAO with BHT and that b) MAO/BHT is harder to ionize than unmodified MAO. A refined formula and cluster size estimation [(AlOMe)0.87(AlMe2bht)0.13]n (n = 57–84) is proposed for MAO/BHT based on this new experimental evidence, accounting for the presence of “structural” AlMe2(bht) units.

A large number of archaeological wooden building poles have been excavated from the Hai Menkou site (Yunnan province, China). Lignin can be transformed and altered accompanied with significant loss of carbohydrates during this process. Elucidation of chemical and structural transformations of lignin is of primary importance for understanding both the nature of degradation processes and the structure of waterlogged archaeological wood, and crucial for developing proper consolidation technology and restoring artifacts of historical and cultural value. In this study, state-of-the-art analytical techniques, including SEM, FT-IR, XRD, CP-MAS 13C NMR, 2D-HSQC NMR, 31P-NMR, CRM, GPC and TG analysis, were all employed to elucidate the structural characteristics of lignin in waterlogged and reference Pinus wood. The results interpreted by NMR analysis demonstrated the depolymerization of lignin via cleavage of β-O-4, β-5, −OCH3 and some LCC linkages, leading to a higher amount of free phenol OH groups in the lignin from the ancient waterlogged wood as compared to that of the reference wood. Microscopically, it was found that extensive degradation of carbohydrates in cell walls was mainly occurred in secondary cell walls, while the lignin concentrations were relatively increased in CCML and S regions in the plant cell wall of the ancient wood.

This paper considers problems of developing a technology for producing low-toxicity formaldehyde resins used in the woodworking industry. It is shown that application 5% fusel alcohol as a modifier at the stage of SFZh-3014 resin synthesis reduces the content of free phenol, formaldehyde, and alkali in the resin and shortens its curing time, as well as increases the strength and water resistance of adhesive joints in woodworking products.

Rh-catalyzed ortho-selective arylation of free phenol with diaryliodonium triflates to widely existed phenol-containing biaryls have been developed. The use of P(NMe2)3, tBuOLi and CH3CN proved to be critical for the ortho-selectivity of this reaction.

Wooden structures in China&rsquo, s ancient buildings hold highly historical and cultural values. There is an urgent need to repair and replace the damaged wooden structures after hundreds and thousands of years of exposure to weather. Unfortunately, to date there is still a lack of insightful understanding on how the chemical structure, composition, and micro-morphology evolve over the long-term natural aging before artificial ancient timbers can be developed. This work aims to systematically examine the outer surface, middle layer, and inner surface of the same piece of Chinese fir (Cunninghamia lanceolate) collected from an ancient Chinese building. Based on qualitative and quantitative analysis, both cellulose and hemicellulose in aged woods are found to experience significant degrees of degradation. The crystalline regions of cellulose are also determined to undergo moderate degradation as compared to the control fresh wood. In comparison, the lignin basically remains unchanged and its content in the inner layer slightly increases, as evidenced by more free phenol groups determined. Relative to the outer and inner layer, the middle layer of the ancient wood shows the lowest degree of degradation close to that of the fresh wood. This work offers guidelines for fabricating artificial ancient woods to repair the destroyed ones in China&rsquo, s ancient architectures.

Aminobismethylenephosphonic acids on a platform of p-tert-butylthiacalix[4]arene were obtained by reacting macrocyclic amines with phosphorous acid and formaldehyde under acid catalysis. Free phenol hydroxy groups on the lower rim of p-tert-butylthiacalix[4]arene were found to inhibit the interaction with the amino moieties of the macrocycle. In the case of amino derivatives of thiacalix[4]arene containing no hydroxy groups the reaction led to the formation of target compounds in good yields.

Steam explosion lignin phenol formaldehyde (SEL–PF) adhesives were prepared by ternary gradual copolymerization. The parameters for the phenolate of steam explosion lignin (SEL) and preparation of SEL–PF adhesives were optimized. Under the optimum phenolate conditions, the phenolic hydroxyl content of lignin increased by 130%, whilst the methoxyl content was reduced by 68%. The SEL–PF adhesives were used to prepare plywoods by hot-pressing. The pH value, viscosity, solid content, free phenol content and free formaldehyde content of SEL–PF adhesives were investigated. The bonding strengths of the plywoods glued with SEL–PF adhesives were determined. The maximum SEL replacement percentage of phenol reached 70 wt%, and the properties of adhesives and plywoods met the Chinese National Standard (GB/T 14732-2006) for first grade plywood.

PhenAll: Recent breakthroughs in site-selective and direct functionalization of free phenols by transition-metal-catalyzed C-O or C-H bond activation are highlighted here as role models for the complete and switchable positional control of transformations of important core structures.

Field trials and laboratory experiments were undertaken for monitoring the relative susceptibility of four potato varieties namely; Atlas, Spunta, Simone and Nicola to potato tuber moth (PTM) Phthorimaea operculella (Zeller) infestations. Ex-periments were carried out for two summer planta-tions during 2006 and 2007. Results obtained indi-cate that Nicola potato variety was the least sus-ceptible one among the four tested varieties. The least infestation (5.5 & 7.17) as average number of larvae/100 leaves, percentages of tuber infestation (5% & 18%) and number of larve/100 tubers (5 & 20) was recorded for Nicola variety in the two sea-sons, respectively. The analysis of variance yield-ed significant differences among the four tested varieties. Positive and highly significant relation-ships were recorded between plant age and the corresponding infestation (r = +0.91 for 2006 and +0.93 for 2007). Chemical analysis for tubers showed a positive relationship between lowest sap content of free phenol and the least level of PTM infestations. That will explain why Nicola variety is considered as least susceptible to PTM infestation where it had the least concentration of free phe-nols (19.507 ppm.). The other verities which demonstrated high concentrations of free phenols harboured the highest levels of infestation with PTM. Positive and highly significant correlation were detected between free phenols content and both tuber infestation & larval content (r=+0.80 and +0.96) respectively.

p-(3-Amino-1-adamantyl)calix[4]arenes with free and alkylated lower rim, representing conjugates of the aminoadamantane pharmacophore fragment and the calixarene platform, were synthesized for the first time by the Curtius rearrangement route starting from p-(3-carboxy-1-adamantyl)calix[4]arenes. The synthesized compounds were evaluated for activity against herpes simplex virus 2 (HSV-2). The nonalkylated compound with free phenol hydroxy groups is the first aminoadamantylcalixarene reported to possess antiviral properties (chemotherapeutic safety index, SI ≈ 12.5). Alkylation at the lower rim of the calixarene platform leads to an increase in cytotoxicity and to the disappearance of anti-HSV activity.

Understanding the failure mechanisms of resin-coated proppants under extreme environments facilitates the development of stronger proppants for superior long-term performance in the oil and gas sector. In the current study, the leaching behavior of Novolac resin-coated proppants (RCPs) and that of polyurethane (PU) based RCPs with aqueous media under different pH conditions and at elevated temperatures have been critically examined, to assess their chemical stability and integrity. Our study indicates that Novolac-based RCPs are substantially more stable to leaching conditions at 250 °F compared to PU-based RCPs. An in-depth nuclear magnetic resonance analysis of the aqueous leachates from the RCP systems reveals that the averaged total levels of the leached components from the PU-based RCPs is five- to sevenfold higher than those of the Novolac RCPs at the higher temperature. In addition, a critical examination of the Novolac RCPs from a product safety and environmental health viewpoint is accomplished by ultraviolet–visible spectrophotometric analysis of the aqueous leachates. The findings reveal that the concentrations of the phenolics, including free phenol, are lower than the detectable limits (

To prepare a low-formaldehyde soy-based adhesive with good water resistance, phenol-formaldehyde modified with glutaraldehyde (PFG) with lower free phenol and free formaldehyde contents was used to cross-link the soy-based adhesive. The results showed that the mechanical properties and water resistance of plywood prepared with soy-based adhesive with PFG was better than that of plywood with the same amount of phenol-formaldehyde (PF). The reaction between phenol and glutaraldehyde was proved by 13C-NMR. Under the optimized preparation conditions for plywood, that is to say, press temperature 160 °C, press time 4 min and resin loading 320 g·m−2, type I plywood could be prepared with 9% PFG as a cross-linker of soy-based adhesive. The Differential Scanning Calorimetry (DSC) result confirmed the cross-linking reaction between soy-based adhesive and PFG or PF. The activation energy of soy-based adhesive with cross-linker PFG was higher than that with PF resin.

Review: recent breakthroughs in site-selective and direct functionalization of free phenols by transition-metal-catalyzed C—O or C—H bond activation; 22 refs.

Palladium-catalyzed hydroformylation of 3-iodo-L-tyrosine derivatives la,b followed by protection of the free phenol as its benzyl ether and Baeyer-Villiger oxidation of the 3-formyl group provided the desired L-Dopa derivatives 4b,c in 71 and 68% overall yields, respectively.

The authors review the literature sources and patents of foreign companies in the field of application of high-carbon organic binders for refractories, composites and technical ceramics. The review reveals the advantages of the new generation of binders with improved properties and describes binders meeting contemporary environmental requirements and not containing free phenol and other carcinogenic and toxic components.

Curing of novalak resin has been investigated by applying different thermal analysis methods and solvent extraction technique. Results revealed that cure can be optimized by finding the critical steps in cure and hold resin in these steps for appropriate time. Best results were also achieved by using resins which contained lower free phenol and hexamine amount. Application of pressure is necessary in initial stages of cure but found to be harmful in the final stages. It was also found that due to the defects produced in the final stages of curing, this process cannot be completed and long time post cure should be applied on these resins. By applying a special curing regime, it was proved that defects during pyrolysis stage could be decreased profoundly and a carbon residue of more than 67 percent expected. The results are explained by emphasis on carbon – carbon applications.

Determination of acid phosphatase (E.C. 3.1.3.2.) activity in meat and meat products Is based on spectrophotometric measurement of free phenol released from phenyl phosphate substrate during enzyme catalysis under prescribed conditions. Precision parameters of a new modified phosphatase assay, proposed for determination of extent of heating of canned picnics and hams, were evaluated in an interlaboratory study with 10 (1 German, 2 Italian, and 7 Hungarian) participating laboratories. The test materials were 5 lean meat batters subjected to different heat treatments (i.e., with different levels of phosphatase activity). The materials were presented to participants as 10 randomly coded samples (2 blind replicates of each material). The interlaboratory study was then repeated with 3 test materials and 2 blind replicates (3 × 2) prepared in the same way. The repeatability relative standard deviation (RSDr), outliers excluded, varied from 2.2 to 10.7%, and the reproducibility relative standard deviation (RSDR) varied from 12.6 to 25.3%. Results were compared with other data in the literature. The sensitivity of the new modified phosphatase assay was also compared with that of the original procedure described in USDA Chemistry Laboratory Guidebook. A higher sensitivity was observed for the method described in this paper. However, the method’s reproducibility was poorer than that of common analytical methods. Although high, the variability may still be acceptable for determining phosphatase activity to assess extent of heat treatment of canned picnics and hams.

A gas chromatography-mass spectrometry technique was used for the analysis of trace phenol in poly(vinyl chloride) products. A pre-concentration of samples was made by using a solid-phase extraction cartridge, previously developed for wastewater. The cartridge extraction of several samples yielded recoveries better than 90%. The relative standard deviation of overall recoveries for ten different samples was less than 7%. The detection limit achieved was less than 10 ppb (w/w) for free phenol measured in plastic materials.