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Christoph F Gfeller,1 Rita Wanser,2 Harish Mahalingam,2 David J Moore,3 Xuying Wang,4 Connie B Lin,4 Gilbert Shanga,5 Gary Grove,6 Anthony V Rawlings7 1GlaxoSmithKline Consumer Healthcare, Medical Affairs Skin Health, Weybridge, Surrey, UK; 2GlaxoSmithKline Consumer Healthcare, Medical Affairs Skin Health, Warren, NJ, USA; 3GlaxoSmithKline Consumer Healthcare, R&D Innovation Skin Health, Weybridge, Surrey, UK; 4GlaxoSmithKline Consumer Healthcare, R&D Innovation Skin Health, Collegeville, PA, USA; 5GSK Consumer Healthcare, Biostatistics, Warren, NJ, USA; 6cyberDERM, Inc., Broomall, PA, USA; 7AVR Consulting, Ltd., Cheshire, UK Purpose: These studies describe the testing of a novel, daily-use lip cream designed for individuals with lips prone to recurrent herpes labialis (RHL) that protects against environmental triggers.Subjects and methods: In vitro occlusive and in vitro and in vivo photoprotection analyses, a characterization of normal vs dry lips, and a randomized, evaluator-blinded, clinical trial that assessed the lip cream in healthy subjects with dry lips were conducted. In the clinical trial, subjects applied the lip cream or were untreated and evaluated using transepidermal water loss (TEWL), corneometry, visual assessments of lip dryness, expert photographic evaluations, and subject-rated outcomes.Results: The lip cream’s in vitro water vapor transmission rate (84.1 g/(m2 h)) indicated moderate occlusivity. The lip cream, but not placebo or control (water), reduced ultraviolet A (UVA)- and UVB-induced DNA damage, and tumor necrosis factor-α (EpiDermFT) and prostaglandin E2 release (EpiDermFT and EpiGingival™). The lip cream’s in vivo sun protection factor (SPF) was 12.2 (lower confidence limit, 11.3) and SPF/UVA protection factor ratio was 0.9. The characterization of dry vs normal lips identified differences in moisturization. In the clinical trial, the lip cream significantly decreased TEWL (difference: –7.19 [95% CI: −11.41, –2.98]; P

A floating polymer-supported photocatalyst based on polystyrene impregnated with titanium dioxide particles was developed using a facile solvent-cast method at ambient temperature. The prepared photocatalysts were characterized by X-ray diffraction, scanning electron microscopy and fourier transform infrared spectroscopy. The photocatalytic activity of the developed photocatalysts was investigated using methylene blue dye. The prepared polystyrene-supported titanium dioxide photocatalysts successfully removed color from the aqueous solution without any additional pH adjustment under ultraviolet (254 nm) irradiation and non-stirred, non-anchored conditions. The maximum color removal achieved by the optimized photocatalyst (10 weight percent loading of Degussa P25 with respect to amount of polystyrene) was around 93% after 7.5 h of ultraviolet light exposure. Further, the photocatalyst sheets were also tested for recovery and reuse. The efficiency of color removal achieved by the optimized photocatalyst on reuse was in the range of 99-100%. The developed photocatalyst seems to be a promising candidate that can be further investigated for large scale commercial applications. [ABSTRACT FROM AUTHOR]

Effective logistics is the key to improving supply chain performance. Tank containers are attractive from the viewpoints of safety, cost, and environment, and are widely used for transporting fluid chemicals. Minimizing the logistics costs arising from the container flow imbalances across the globe and container cleaning is a major issue that chemical companies and affiliated third-party logistics firms face routinely. In contrast to dry containers, this important problem of managing tank containers in global chemical logistics has received no attention. An innovative, event-based, "pull" approach is presented for the minimum-cost or the maximum-profit scheduling of the transport and cleaning of multiproduct tank containers (loaded and empty) given a set of projected shipment orders. A novel linear programming formulation is developed and illustrated through examples that successfully solves large, industrially relevant problems with key practical considerations such as alternate ship schedules, delivery time windows, and intermodal transport routes. [ABSTRACT FROM AUTHOR]

Patterning antidots, which are regions of potential hills that repel electrons, into well-defined antidot lattices creates fascinating artificial periodic structures, leading to anomalous transport properties and exotic quantum phenomena in two-dimensional systems. Although nanolithography has brought conventional antidots from the semiclassical regime to the quantum regime, achieving precise control over the size of each antidot and its spatial period at the atomic scale has remained challenging. However, attaining such control opens the door to a new paradigm, enabling the creation of quantum antidots with discrete quantum hole states, which, in turn, offer a fertile platform to explore novel quantum phenomena and hot electron dynamics in previously inaccessible regimes. Here we report an atomically precise bottom-up fabrication of a series of atomic-scale quantum antidots through a thermal-induced assembly of a chalcogenide single vacancy in PtTe 2 . Such quantum antidots consist of highly ordered single-vacancy lattices, spaced by a single Te atom, reaching the ultimate downscaling limit of antidot lattices. Increasing the number of single vacancies in quantum antidots strengthens the cumulative repulsive potential and consequently enhances the collective interference of multiple-pocket scattered quasiparticles inside quantum antidots, creating multilevel quantum hole states with a tunable gap from the telecom to far-infrared regime. Moreover, precisely engineered quantum hole states of quantum antidots are geometry protected and thus survive on oxygen substitutional doping. Therefore, single-vacancy-assembled quantum antidots exhibit unprecedented robustness and property tunability, positioning them as highly promising candidates for advancing quantum information and photocatalysis technologies., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Objective: To determine the association between medial femoral condyle hypoplasia and trochlear dysplasia by analyzing the knee magnetic resonance imaging scans of young patients with or without trochlear dysplasia., Materials and Methods: This was a retrospective analysis of magnetic resonance imaging scans of the knees of young individuals (16-35 years of age): 30 patients with trochlear dysplasia and 30 individuals with no signs of patellofemoral instability. The ratios between the depth, width, and height of the medial and lateral femoral condyles (dLC/dMC, wLC/wMC, and hLC/hMC, respectively) were calculated, as was the ratio between the width of the medial condyle and the total width of the femur (wMC/FW). All of the values were determined in consensus by two radiologists., Results: We evaluated 60 patients: 30 with trochlear dysplasia and 30 without. The mean dLC/dMC, wLC/wMC, and hLC/hMC ratios were higher in the patients than in the controls ( p < 0.05), whereas the mean wMC/FW ratio was lower in the patients ( p < 0.05). The optimal cutoff values, obtained by calculating the areas under the receiver operating characteristic curves, were 1.0465 for the dLC/dMC ratio (76% sensitivity and 63.3% specificity), 0.958 for the wLC/wMC ratio (80% sensitivity and 73.3% specificity), and 1.080 for the hLC/hMC ratio (93.3% sensitivity and 93.3% specificity)., Conclusion: Our findings confirm our hypothesis that trochlear dysplasia is associated with medial condyle hypoplasia.

The emerging global problem of antimicrobial resistance needs immediate attention. In this regard, this work demonstrates the use of expanded polystyrene waste in the synthesis of immobilized photocatalytic films for the treatment of antibiotics as well as for bacterial disinfection. A boron-cerium codoped TiO 2 catalyst (of specific composition: B 0.8 Ce 0.2 TiO 2 ) was immobilized in an expanded polystyrene (EPS) film prepared from waste EPS beads. These films were studied for the degradation of ciprofloxacin (CIP) and disinfection of E. coli under sunlight. The film with a catalyst loading of 20 wt% showed a maximum degradation of 89% in 240 min with a corresponding TOC reduction of 84%. A 7.4 and 6.3 log reduction from the bacterial inactivation studies in the presence and absence of antibiotics, respectively, was obtained. The EPS film was stable after five times of reuse, and no significant chemical changes in the used film were observed from FTIR analysis. The average thickness of the prepared film was found from FESEM analysis to be 1.09 mm. These EPS films were also tested for degradation of other antibiotics, such as norfloxacin, levofloxacin and moxifloxacin. The EPS films were tested in two different reactor volumes at optimum conditions. Also, the effectiveness of B 0.8 Ce 0.2 TiO 2 /EPS film in real water samples indicates its potential in large-scale and real-world applications. Thus, these B 0.8 Ce 0.2 TiO 2 /EPS films can be effectively employed for both degradation of ciprofloxacin and the disinfection of E. coli under solar light to solve the increasing problem of antimicrobial resistance., (© 2023. Springer Nature Limited.)

Competing Interests: None

A novel BiOY (Y = Br/Cl) heterojunction nanocatalyst was synthesised chemically and compared with three different BiOX (X = Br/Cl/I) nanocatalysts as well as a physical admixture of BiOBr/BiOCl catalysts in the photocatalytic degradation of malachite green dye wastewater under solar irradiation in both suspended and immobilised forms using polysulfone as the substrate. Catalyst characterisation was done by a particle size analyser, SEM/EDX, XRD, FTIR, and DRS. In the suspended form, BiOBr showed 100% degradation within 70 min, BiOCl showed 99.3%, and BiOI showed 11.2% degradation within 120 min, and it is found to follow pseudo-first-order kinetics. In the immobilised form, BiOBr showed 89.1%, and BiOCl showed 83.4% degradation within 180 min under sunlight. The degradation measured by TOC reduction for these catalysts in suspended form was 67.4%, 57%, and 40%, affirming BiOBr as the best among these catalysts. The performance of the immobilised chemically synthesised BiOY and physical admixture catalysts were 88% and 14%, respectively. The enhanced activity in the chemically synthesised immobilised BiOBr/Cl catalyst can be attributed to the effective charge separation at the heterojunction interface. These photocatalysts are very active under solar light and hence suitable for the efficient degradation of other recalcitrant organic contaminants., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

We introduce a computationally efficient method based on the path integral formalism to describe defect-modified graphene. By taking into account the entire Brillouin zone, our approach respects the lattice symmetry and can be used to investigate both short-range and long-range effects. The proposed method's key advantage is that the computational complexity does not increase with the system size, scaling, instead, with the number of defects. Our aim is to make the quantum-field calculations in graphene accessible to the experimental community. We demonstrate our method's capabilities by exploring the well-known graphene-mediated Ruderman-Kittel-Kasuya-Yoshida interaction and by performing a detailed study of the atomic collapse in the presence of defects., (© 2022 IOP Publishing Ltd.)

Since its use for photochemical water splitting reported first in 1972, TiO 2 is one of the most extensively studied photocatalysts for a diverse range of applications. Monodoping or codoping of the catalyst is a proven strategy to enhance the functionality of TiO 2 under solar or visible light. However, the use of three or more dopants in the development of more efficient and visible light active photocatalysts has not been investigated widely, especially for microbial disinfection. Boron/cerium/silver tridoped TiO 2 photocatalysts with curated amounts of the dopants (B = 1, 2 at.%, Ce = 0.1 at.%, Ag = 0.06 at.%), synthesized by the ecofriendly EDTA-citrate method, were evaluated for the disinfection of water using Enterococcus faecalis under UV-A irradiation and degradation of levofloxacin antibiotic under solar light. The catalyst characterization revealed that the spherical nanoparticles had a crystallite size of ~ 13 nm and bandgap energy values of 2.8-2.9 eV. 2B-0.1Ce-0.06Ag-TiO 2 is the best catalyst for microbial disinfection with a log reduction and kinetic rate constant ~ 30 and ~ 4.5 times higher than those values determined for the other codoped or monodoped catalysts, confirming an enhanced performance. Regarding levofloxacin degradation, the best performing catalyst is 1B-0.1Ce-0.06Ag-TiO 2 with degradation of 99% and 83% COD reduction in 100 min. The tridoped photocatalysts are very effective in the inactivation of Enterococcus faecalis, thus solving the problem of antimicrobial resistance in waters containing antibiotic residues., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

We report that monoelemental black phosphorus presents a new electronic self-passivation scheme of single vacancy (SV). By means of low-temperature scanning tunneling microscopy and noncontact atomic force microscopy, we demonstrate that the local reconstruction and ionization of SV into negatively charged SV^{-} leads to the passivation of dangling bonds and, thus, the quenching of in-gap states, which can be achieved by mild thermal annealing or STM tip manipulation. SV exhibits a strong and symmetric Friedel oscillation (FO) pattern, while SV^{-} shows an asymmetric FO pattern with local perturbation amplitude reduced by one order of magnitude and a faster decay rate. The enhanced passivation by forming SV^{-} can be attributed to its weak dipolelike perturbation, consistent with density-functional theory numerical calculations. Therefore, self-passivated SV^{-} is electrically benign and acts as a much weaker scattering center, which may hold the key to further enhance the charge mobility of black phosphorus and its analogs.

Creating atomically precise quantum architectures with high digital fidelity and desired quantum states is an important goal in a new era of quantum technology. The strategy of creating these quantum nanostructures mainly relies on atom-by-atom, molecule-by-molecule manipulation or molecular assembly through non-covalent interactions, which thus lack sufficient chemical robustness required for on-chip quantum device operation at elevated temperature. Here, we report a bottom-up synthesis of covalently linked organic quantum corrals (OQCs) with atomic precision to induce the formation of topology-controlled quantum resonance states, arising from a collective interference of scattered electron waves inside the quantum nanocavities. Individual OQCs host a series of atomic orbital-like resonance states whose orbital hybridization into artificial homo-diatomic and hetero-diatomic molecular-like resonance states can be constructed in Cassini oval-shaped OQCs with desired topologies corroborated by joint ab initio and analytic calculations. Our studies open up a new avenue to fabricate covalently linked large-sized OQCs with atomic precision to engineer desired quantum states with high chemical robustness and digital fidelity for future practical applications., (© 2021. The Author(s).)

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is a clinico-radiological syndrome in children secondary to viral or bacterial infections. The causes include viral (influenza, human herpes virus-6, adenovirus, rota) as well as bacterial infections. However, AESD with dengue infection has not been reported earlier. Here, we present an infant with dengue infection and AESD which recovered completely following treatment with intravenous human immunoglobulin therapy. A 9-month-old girl presented with seizures following fever and loose stools. Seizures recurred after 2 days of seizure-free interval. Cerebrospinal fluid analysis was not contributory. Dengue infection was confirmed by lab tests. Magnetic resonance imaging brain after the second seizure revealed diffusion restriction involving the bilateral frontal and parietal white matter, both hemispheres with a typical central perisylvian sparing lesion suggestive of AESD. This case report expands the reported spectrum of neurological manifestations of dengue infection., (© The Author(s) [2020]. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Facial chemical exfoliation (peeling) involves using a chemical agent to insult the skin and damage the cutaneous barrier, to reduce the signs of aging. The use of a moisturizer is advised postprocedure to promote repair of the epidermis. Biomimic moisturizer formulations may be effective treatment options for repair following facial peeling., Aims: The aim of this study was to assess the local tolerance and cosmetic efficacy of three topical moisturizers (Physiogel® moisturizing creams), used after a 70% glycolic acid facial peel., Methods: Three randomized, evaluator-blind, parallel group studies were performed. Subjects were healthy females aged 30-60 years with moderate to advanced photoaged skin (Glogau photoaging type II-III). All included a screening visit, a 7-day washout period, a 70% glycolic acid facial peeling procedure, and randomization to a 14-day treatment period with one of the three test products vs control., Results: The primary endpoint was reached in all three studies; all completed subjects in the test groups received a favorable dermatologist global assessment score for tolerance at Day 14 (postchemical peel). Secondary assessments of local tolerance based on dermatologist and subject self-assessment scores demonstrated improvements from baseline. No treatment-related adverse events were reported in any study. Benefits for the test products were also observed in secondary efficacy analyses of transepidermal water loss and moisturization., Conclusions: These studies have demonstrated the local tolerance and cosmetic efficacy of three moisturizing skin care products, when used for skin recovery after superficial chemical peeling on the face., (© 2019 Wiley Periodicals, Inc.)

Reduced graphene oxide (rGO) as well as graphitic carbon nitride (g-C 3 N 4 ) catalysts were synthesized and a physical admixture of rGO and g-C 3 N 4 along with TiO 2 in the ratio of 1:1:1 by weight was immobilized in a polystyrene film using the facile solvent casting method. An internal loop airlift reactor with a working volume of 1.2 litres incorporating the prepared polymer-based photocatalytic film was designed and tested for the photocatalytic degradation of remazol turquoise blue dye synthetic wastewater. The reactor parameters affecting the photocatalytic activity such as airflow rate and D i /D o (ratio of draft tube diameter to outer tube diameter) were evaluated. The successful operation of the reactor obtained using the ternary immobilized catalyst mixture film gave 92.25% total organic carbon reduction and 94% decolourization within 140 min, compared to 91% decolourization by the slurry form within 40 min. Complete and quicker decolourization of the dye was also demonstrated under the influence of O 3 or H 2 O 2 . The immobilized catalyst was successfully reused four times. The ternary catalyst admixture employed in this work and the unique design of the photocatalytic reactor helps to increase the degradation rate of toxic textile effluents thus making it suitable for larger scales of treatment., (Copyright © 2019 Elsevier B.V. All rights reserved.)

This report explores dry-skin models to assess the potential of a new lip balm formulation to hydrate dry skin or lips, and presents sun protection factor (SPF) values for five new lip balm formulations. Evaporimeter [for transepidermal water loss (TEWL)], Skicon ® , and Corneometer ® were used to measure hydrating effects of lip balm formulations in a dry-skin leg model, and TEWL, DermaLab ® Moisture Meter, Corneometer ® , and visual assessments were used with a dry-lip model. SPF studies were conducted in accordance with either the U.S. Food and Drug Administration monograph final rule or international standard ISO 24444. Data from dry-skin leg model demonstrate that a new lip balm formulation significantly improves skin hydration compared with untreated leg skin and four comparator products. Data obtained from a dry-lip model proved unreliable. Five new lip balm formulations exhibited sunscreen capability; however, they did not meet the intended SPF. There were no product-related adverse events with the formulations. Although the new lip balm formulation improved hydration, data from a novel dry-lip model proved unreliable therefore further testing is required to confirm these benefits. Five new lip balm formulations provided sunscreen capability but did not meet the intended SPF, and will undergo reformulation and retesting.

Context: The pattern of myocardial nulling in the inversion scout sequence [time of inversion scout (TIS)] of cardiac magnetic resonance imaging (MRI) is an accurate tool to detect cardiac amyloidosis. The pattern of nulling of myocardium and blood at varying times post gadolinium injection and its relationship with left ventricular mass (LVM) in amyloidosis have not been described previously., Aims: The aim is to study the nulling pattern of myocardium and blood at varying times in TIS and assess its relationship with LVM and late gadolinium enhancement (LGE) in amyloidosis., Materials and Methods: This was a retrospective study of 109 patients with clinical suspicion of cardiac amyloidosis who underwent MRI. Of these, 30 had MRI features of amyloidosis. The nulling pattern was assessed at 5 (TIS 5min ) and 10 (TIS 10min ) minutes (min) post contrast injection. Nulling pattern was also assessed at 3min (TIS 3min ) in four patients and 7min (TIS 7min ) in five patients. Myocardial mass index was calculated. Mann-Whitney U test was done to assess statistical difference in the myocardial mass index between patients with and without reversed nulling pattern (RNP) at TIS 5min ., Results: RNP was observed in 58% at TIS 5min and 89.6% at TIS 10min . Myocardial mass index was significantly higher in patients with RNP at TIS 5min [mean = 94.87 g/m 2 ; standard deviation (SD) =17.63) when compared with patients with normal pattern (mean = 77.61 g/m 2 ; SD = 17.21) ( U = 18; P = 0.0351)., Conclusion: In cardiac amyloidosis, TIS sequence shows temporal variability in nulling pattern. Earlier onset of reverse nulling pattern shows a trend toward more LVM and possibly more severe amyloid load., Competing Interests: There are no conflicts of interest.

Competing Interests: Compliance with Ethical StandardsThere is no conflict of interest between the authors.Informed signed written consent was taken from the patient involved.All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.No animals were involved in the study.

Purpose: This study aimed to assess the accuracy of low-dose dual-energy computed tomography (DECT) in predicting the composition of urinary calculi., Materials and Methods: A total of 52 patients with urinary calculi were scanned with a 128-slice dual-source DECT scanner by use of a low-dose protocol. Dual-energy (DE) ratio, weighted average Hounsfield unit (HU) of calculi, radiation dose, and image noise levels were recorded. Two radiologists independently rated study quality. Stone composition was assessed after extraction by Fourier transform infrared spectroscopy (FTIRS). Analysis of variance was used to determine if the differences in HU values and DE ratios between the various calculus groups were significant. Threshold cutoff values to classify the calculi into separate groups were identified by receiver operating characteristic curve analysis., Results: A total of 137 calculi were detected. FTIRS analysis differentiated the calculi into five groups: uric acid (n=17), struvite (n=3), calcium oxalate monohydrate and dihydrate (COM-COD, n=84), calcium oxalate monohydrate (COM, n=28), and carbonate apatite (n=5). The HU value could differentiate only uric acid calculi from calcified calculi (p<0.001). The DE ratio could confidently differentiate uric acid, struvite, calcium oxalate, and carbonate apatite calculi (p<0.001) with cutoff values of 1.12, 1.34, and 1.66, respectively, giving >80% sensitivity and specificity to differentiate them. The DE ratio could not differentiate COM from COM-COD calculi. No study was rated poor in quality by either of the observers. The mean radiation dose was 1.8 mSv., Conclusions: Low-dose DECT accurately predicts urinary calculus composition in vivo while simultaneously reducing radiation exposure without compromising study quality.

A combination of techniques, including high-performance liquid chromatography (HPLC), spectrophotometric measurements, and a novel method for quantifying melanosome morphology, were applied to the analysis of melanin content and composition in highly pigmented (Fitzpatrick type V and VI) human skin. We found that total epidermal melanin content is significantly elevated in photoexposed type V and VI skin (approximately 1.6 x), while analysis of individual melanin components suggests that pheomelanin content increases only slightly, whereas 5,6-dihydroxyindole-2-carboxylic acid (DHICA)-eumelanin and to a greater extent 5,6-dihydroxyindole (DHI)-eumelanin content are both markedly elevated. Analysis of the relative composition of epidermal melanin in these subjects revealed that DHI-eumelanin is the largest single component (approximately 60-70%), followed by DHICA-eumelanin (25-35%), with pheomelanin being a relatively minor component (2-8%). Moreover, there was a comparative enrichment of DHI-eumelanin at photoexposed sites, with a corresponding decline in the relative contributions from DHICA-eumelanin and pheomelanin. There was also a good correlation and close agreement between the concentration of spheroidal melanosomes determined by morphological image analysis and the concentration of pheomelanin determined by a combination of HPLC and spectrophotometric analysis (r = 0.89, P < 0.02). This study demonstrates the usefulness of melanosome morphology analysis as a sensitive new method for the quantification of melanin composition in human skin. The data also suggest that DHI-eumelanin formation is the dominant pathway for melanin synthesis in heavily pigmented (Fitzpatrick V and VI) skin types in vivo, and is the favoured pathway when melanin production is increased in chronically photoexposed skin.

Melanogenesis is regulated by a variety of environmental and hormonal factors. In this study, we showed that protein kinase C (PKC) plays a major role in regulating melanogenesis in B16 mouse melanoma cells. Chronic treatment of B16 cells with phorbol dibutyrate resulted in a concentration-dependent loss of density-dependent induction of tyrosinase activity, which correlated positively with a concentration-dependent loss of PKC enzyme activity. In contrast, B16 clones overexpressing PKC alpha had increased tyrosinase activity. Different phorbol derivatives inhibited tyrosinase activity and depleted cellular PKC alpha in a manner that reflected their reported tumor-promoting activity. Western blotting analysis showed that phorbol dibutyrate decreased the amount of the brown locus gene product (TRP-1) by 50% and lowered the amount of the albino locus gene product (tyrosinase) to undetectable levels. None of the phorbol derivatives affected the level of the slaty locus protein (TRP-2). The decrease in tyrosinase and TRP-1 protein levels was found to be due to a decrease in the mRNA encoded by these genes. In addition to inhibiting the density-dependent increase in tyrosinase activity, phorbol dibutyrate inhibited some, but not all, of the 8-bromocyclic AMP-induced increase in tyrosinase activity. This was accompanied by a decrease in the amount of tyrosinase protein induced by 8-bromocyclic AMP. Although 8-bromocyclic AMP did not change the level of TRP-1, it did reverse the decrease in the amount of this protein induced by phorbol dibutyrate. The amount of TRP-2 was not altered by any of these agents. These data suggest that PKC regulates melanogenesis primarily by controlling the constitutive expression of tyrosinase and, to a lesser extent, TRP-1.