Investigation of the Photochromism of WO3, TiO2, and Composite WO3-TiO2 Nanoparticles

We report the synthesis of WO3, TiO2, and TiO2-WO3 nanoparticles by a polyol route, with the objective of studying the influence of the preparation method on their photochromic properties. By combining transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and diffuse reflectance experiments, we show that low W6+ concentrations and high ripening temperatures allow the preparation of WO3 nanoparticles with high photochromic efficiency. WO3-TiO2 nanocomposites (NCs) prepared by the introduction of a TiO2+ solution in a WO3 nanoparticle suspension exhibit a strong coloring photochromism, which is attributed to the TiO2 coating of the WO3 nanoparticles as it involves the formation of W-O-Ti oxo-bonds in place of W5+-νO defects. Especially, after an oxidative treatment in order to obtain an initial pale-yellow material, such WO3-TiO2 NCs exhibit a fully reversible photochromism with a large contrast between the colored and bleached state. They could therefore be incorporated in hybrid smart films for solar control on building window glasses. On the other hand, while the WO3-TiO2 NCs are functionalized with DPA (n-dodecyl phosphonic acid), the as-prepared nanocomposites exhibit exacerbated coloring contrast but with a nearly nonreversible photochromism (very limited bleaching), which makes them good candidates for the fabrication of smart UV-sensor devices that can indicate the cumulative UV dose which is received.

Silver Nanowire-Based Transparent Electrodes for V2O5 Thin Films with Electrochromic Properties

The development of electrochromic systems, known for the modulation of their optical properties under an applied voltage, depends on the replacement of the state-of-the-art ITO (In2O3:Sn) transparent electrode (TE) as well as the improvement of electrochromic films. This study presents an innovative ITO-free electrochromic film architecture utilizing oxide-coated silver nanowire (AgNW) networks as a TE and V2O5 as an electrochromic oxide layer. The TE was prepared by simple spray deposition of AgNWs that allowed for tuning different densities of the network and hence the resistance and transparency of the film. The conformal oxide coating (SnO2 or ZnO) on AgNWs was deposited by atmospheric-pressure spatial atomic layer deposition, an open-air fast and scalable process yielding a highly stable electrode. V2O5 thin films were then deposited by radio frequency magnetron sputtering on the AgNW-based TE. Independent of the oxide's nature, a 20 nm protective layer thickness was insufficient to prevent the deterioration of the AgNW network during V2O5 deposition. On the contrary, crystalline V2O5 films were grown on 30 nm thick ZnO or SnO2-coated AgNWs, exhibiting a typical orange color. Electrochromic characterization demonstrated that only V2O5 films deposited on 30 nm thick SnO2-coated AgNW showed characteristic oxidation-reduction peaks in the Li+-based liquid electrolyte associated with a reversible orange-to-blue color switch for at least 500 cycles. The electrochromic key properties of AgNW/SnO2 (30 nm)/V2O5 films are discussed in terms of structural and morphological changes due to the AgNW network and the nature and thickness of the two protective oxide coatings.

Insight into the generation of near infra-red (NIR) absorbing species in electrochromic surface-anchored metal-organic frameworks

Due to their versatility and easy processing, Surface-Anchored Metal-Organic Frameworks (SurMOFs) have gained interest in recent times as promising electrochromic thin films. Herein a step forward in their use and characterization was achieved thanks to the integration of {Zn2(PDICl4)2} SurMOFs in a multi-layer electrochromic device (ECD), based on a membrane-like electrolyte. The optical and electrochemical properties of the ECD were fully characterized, revealing a two-step reduction process localized on the organic ligand and involving subsequent near infra-red (NIR) and cyan absorbing states, leading to optical modulation of the films. The species responsible for this absorption were isolated and identified in the reduced states. In parallel to experimental characterization, quantum chemistry was successfully used to investigate the structure-property relationship of the SurMOF, revealing additional information regarding the structure and the local environment of the electrochromic ligand.

Toward the Prediction of Electrochromic Properties of WO3 Films: Combination of Experimental and Machine Learning Approaches

WO₃ is the state of the art of electrochromic oxide materials finding technological application in smart windows. In this work, a set of WO₃ thin films were deposited by magnetron sputtering by varying total pressure, oxygen partial pressure, and power. On each film two properties were measured, the electrochemical reversibility and the blue color persistence of Li_xWO₃ films in simulated ambient conditions. With the help of machine learning, prediction maps for such electrochromic properties, namely, color persistence and reversibility, were designed. High-performance WO₃ films were targeted by a global score which is the product of these two properties. The combined approach of experimental measurements and machine learning led to a complete picture of electrochromic properties depending of sputtering parameters providing an efficient tool in regards to time saving.

Synthesis and Characterization of Micro/Nanoscale VO2(M) through Vanadylethylene Glycolate Decomposition

Thanks to a homemade dynamic vacuum system, fully crystallized VO₂ (M) is successfully synthesized in a merged step of vanadyl ethylene glycolate (VEG) decomposition and crystallization of VO₂ at high temperatures (>500 °C). During the whole process, vanadium valence (+4) is well maintained, and VEG microstructure plays an important role in the end-product size and shape. Finally, the suggested route appears well suitable for the mass production of VO₂ nanoparticles.

Doubling of the Phase Transition Temperature of VO2 by Fe Doping

Vanadium dioxide (VO₂) undergoes a fully reversible first-order metal-insulator transition from the M1 monoclinic phase (P2₁/c) to a high-temperature tetragonal phase (P4₂/mnm) at around 68 °C. Modulation of the phase transition of VO₂ by chemical doping is of fundamental and technological interest. Here, we report the synthesis of highly crystallized Fe-doped VO₂ powders by a carbo-thermal reduction process. The impact of Fe doping on the structural and phase transition of VO₂ is studied. The as-prepared Fe-doped VO₂ samples crystallize in the M2 monoclinic form (C2/m), which is linked to segregation of the doping ions in the V2 zigzag chains. A large increase in the transition temperature to 134 °C is observed, which does correspond to a breakthrough in VO₂-type thermochromic materials.

Influence of Quenching on the Opto-Electronic Properties of F:SnO2 Layers

For many opto-electronic applications, F:SnO₂ materials must benefit from high transparency, high conductivity, and high mechanical strength even after quenching. The purpose of this study was to investigate the influence of quenching on the opto-electronic properties of the F:SnO₂ layers synthesized at high temperature on Si _x C _y O-coated soda-lime glass by atmospheric chemical vapor deposition. The morphology, structure, and composition of the layers were studied before and after quenching in air- and oxygen-rich atmospheres at 670 °C. The free carrier concentration was reduced by oxygen vacancy (V_O) passivation, as well as by F and Na diffusion, with all effects scaling up with quenching time in air. The transmittance also decreased with quenching time as Na impurities acted as absorption and electron recombination centers. In an oxygen-rich atmosphere, the V_O passivation was even more emphasized, with however a moderate contribution to conductivity loss. The F:SnO₂ layer microstructure and composition were rather fringed through high-temperature deposition. The almost invariable free carrier concentration and transmittance of the F:SnO₂ samples quenched in O₂ versus air were related to a moderation in Na diffusion. For long quenching times (>20 min) in air, Na and F diffusion prevailed explaining the conductivity drop.

Toward Simplified Electrochromic Devices Using Silver as Counter Electrode Material

Novel design of electrochromic devices (ECDs) known for their ability to modify optical properties under an applied voltage, based on a minimization of the number of layers is reported. The use of a metallic electrode, playing the role of both the conductive layer and the counter electrode, allows us to simplify the assembly of a commonly five-layer battery-type device to four-layer ECD. Further minimization of the number of layers is achieved using a conductive and electrochromic material. The novelty of the device configuration is illustrated using poly(3,4-ethylenedioxythiophene) (PEDOT)-based materials as EC layer, lithium-based ionic liquid as electrolyte, and Ag as counter electrode. Such a four- or three-layer ECD deposited on paper substrate switches from light to deep blue in a narrow 0.7 V voltage window. Preliminary investigations of the mechanism indicate traces of Ag on the PEDOT layer upon cycling. Finally, the printed ECD is successfully activated using a mobile phone.

Carbon-reduction as an easy route for the synthesis of VO2 (M1) and further Al, Ti doping

A low-cost and facile method to synthesize highly crystallized VO2 (M1) particles is proposed, using carbon black as the reducing agent mixed with V2O5 nanopowders comparing two types of vacuum systems for the thermal activation. In a sealed vacuum system, CO gas is generated in the first reductive step, and continues to reduce the new born VO2, until all the V (+4) is reduced to V (+3), resulting in V2O3 formation at 1000 °C. In contrast, in a dynamic vacuum system, CO gas is ejected through pumping as soon as it is generated, leading to the formation of pure VO2 (M1) at high temperatures (i.e. in the range 700 °C ≤ T ≤ 1000 °C). The evolution of the carbon content, determined by CHNS, of each sample versus the synthesis conditions, namely temperature and type of vacuum system, confirms that the transformation of V (+5) into V (+4) or V (+3) can be controlled. The characterization of the morphologies and crystal structures of two synthesized VO2 (M1) at 700 °C and 1000 °C shows the possibility to tune the crystallite size from 1.8 to more than 5 μm, with a uniform size distribution and highly crystallized powders. High purity VO2 (M1) leads to strong physical properties illustrated by a high latent energy (∼55 J g-1) during the phase transition obtained from DSC as well as high resistivity changes. In addition, with this method, dopants such as Ti4+ or Al3+ can be successfully introduced into VO2 (M1) thanks to the preparation of Al or Ti-doped nano-V2O5 by co-precipitation in polyol medium before carbon-reduction.

Color Tuning by Oxide Addition in PEDOT:PSS-Based Electrochromic Devices

Poly(3,4-ethylenedi-oxythiophene) (PEDOT) derivatives conducting polymers are known for their great electrochromic (EC) properties offering a reversible blue switch under an applied voltage. Characterizations of symmetrical EC devices, built on combinations of PEDOT thin films, deposited with a bar coater from commercial inks, and separated by a lithium-based ionic membrane, show highest performance for 800 nm thickness. Tuning of the color is further achieved by mixing the PEDOT film with oxides. Taking, in particular, the example of optically inactive iron oxide Fe₂O₃, a dark blue to reddish switch, of which intensity depends on the oxide content, is reported. Careful evaluation of the chromaticity parameters L*, a*, and b*, with oxidizing/reducing potentials, evidences a possible monitoring of the bluish tint.

Structural transformations of the La2−xPrxNiO4+δ system probed by high-resolution synchrotron and neutron powder diffraction

Subtle structural distortions in the La_2−xPr_xNiO_4+δ system are investigated using high resolution X-ray powder diffraction and neutron powder diffraction, analyzed by combined Rietveld refinements.

Geometric considerations of the monoclinic–rutile structural transition in VO2

Geometrical and experimental examinations of VO₂ show how hysteretic phase transition phenomena across the MIT can be driven by positive crystal energy effects of increasing unit cell volume.

Life-cycling and uncovering cation-trapping evidence of a monolithic inorganic electrochromic device: glass/ITO/WO3/LiTaO3/NiO/ITO

The visualization of the microstructure change and of the depth of lithium transport inside a monolithic ElectroChromic Device (ECD) is realized using an innovative combined approach of Focused Ion Beam (FIB), Secondary Ion Mass Spectrometry (SIMS) and Glow Discharge Optical Emission Spectroscopy (GDOES). The electrochemical and optical properties of the all-thin-film inorganic ECD glass/ITO/WO3/LiTaO3/NiO/ITO, deposited by magnetron sputtering, are measured by cycling voltammetry and in situ transmittance analysis up to 11 270 cycles. A significant degradation corresponding to a decrease in the capacity of 71% after 2500 cycles and of 94% after 11 270 cycles is reported. The depth resolved microstructure evolution within the device, investigated by cross-sectional cutting with FIB, points out a progressive densification of the NiO layer upon cycling. The existence of irreversible Li ion trapping in NiO is illustrated through the comparison of the compositional distribution of the device after various cycles 0, 100, 1000, 5000 and 11 270. SIMS and GDOES depth profiles confirm an increase in the trapped Li content in NiO as the number of cycles increases. Therefore, the combination of lithium trapping and apparent morphological densification evolution in NiO is believed to account for the degradation of the ECD properties upon long term cycling of the ECD.

Two-Step Synthesis of VO2 (M) with Tuned Crystallinity

Highly crystallized monoclinic vanadium dioxide, VO₂ (M), is successfully synthesized by a two-step thermal treatment: thermolysis of vanadyl ethylene glycolate (VEG) and postannealing of the poorly crystallized VO₂ powder. In the first thermolysis step, the decomposition of VEG at 300 °C is investigated by X-ray diffraction and scanning electron microscopy (SEM). A poorly crystallized VO₂ powder is obtained at a strict time of 3 min, and it is found that the residual carbon content in the powder played a critical role in the post crystallization of VO₂ (M). After postannealing at 500 and 700 °C in an oxygen-free atmosphere, VO₂ particles of various morphologies, of which the crystallite size increases with increasing temperature, are observed by SEM and transmission electron microscopy. The weight percent of crystalline VO₂, calculated using the Fullprof program, increases from 44% to 79% and 100% after postannealing. The improved crystallinity leads to an improvement in metal-insulator transition behaviors demonstrated by sharper and more intense differential scanning calorimetry peaks. Moreover, V₂O₃ and V₂O₅ with novel and particular microstructures are also successfully prepared with a similar two-step method using postannealing treatment under reductive or oxidizing atmospheres, respectively.

Double-Sided Electrochromic Device Based on Metal-Organic Frameworks

Devices displaying controllably tunable optical properties through an applied voltage are attractive for smart glass, mirrors, and displays. Electrochromic material development aims to decrease power consumption while increasing the variety of attainable colors, their brilliance, and their longevity. We report the first electrochromic device constructed from metal organic frameworks (MOFs). Two MOF films, HKUST-1 and ZnMOF-74, are assembled so that the oxidation of one corresponds to the reduction of the other, allowing the two sides of the device to simultaneously change color. These MOF films exhibit cycling stability unrivaled by other MOFs and a significant optical contrast in a lithium-based electrolyte. HKUST-1 reversibly changed from bright blue to light blue and ZnMOF-74 from yellow to brown. The electrochromic device associates the two MOF films via a PMMA-lithium based electrolyte membrane. The color-switching of these MOFs does not arise from an organic-linker redox reaction, signaling unexplored possibilities for electrochromic MOF-based materials.

Low-Cost and Facile Synthesis of the Vanadium Oxides V2O3, VO2, and V2O5 and Their Magnetic, Thermochromic and Electrochromic Properties

In this study, vanadium sesquioxide (V₂O₃), dioxide (VO₂), and pentoxide (V₂O₅) were all synthesized from a single polyol route through the precipitation of an intermediate precursor: vanadium ethylene glycolate (VEG). Various annealing treatments of the VEG precursor, under controlled atmosphere and temperature, led to the successful synthesis of the three pure oxides, with sub-micrometer crystallite size. To the best of our knowledge, the synthesis of the three oxides V₂O₅, VO₂, and V₂O₃ from a single polyol batch has never been reported in the literature. In a second part of the study, the potentialities brought about by the successful preparation of sub-micrometer V₂O₅, VO₂, and V₂O₃ are illustrated by the characterization of the electrochromic properties of V₂O₅ films, a discussion about the metal to insulator transition of VO₂ on the basis of in situ measurements versus temperature of its electrical and optical properties, and the characterization of the magnetic transition of V₂O₃ powder from SQUID measurements. For the latter compound, the influence of the crystallite size on the magnetic properties is discussed.

Structure and reactivity with oxygen of Pr2NiO4+δ: an in situ synchrotron X-ray powder diffraction study

The high temperature behaviour of the SOFC cathode material Pr₂NiO_4.22 was revisited in situ as function of O₂ partial pressure.

Algorithm for dermocosmetic use in the management of cutaneous side-effects associated with targeted therapy in oncology

Currently, numerous patients who receive targeted chemotherapy for cancer suffer from disabling skin reactions due to cutaneous toxicity, which is a significant problem for an increasing number of patients and their treating physicians. In addition, using inappropriate personal hygiene products often worsens these otherwise manageable side-effects. Cosmetic products for personal hygiene and lesion camouflage are part of a patients’ well-being and an increasing number of physicians feel that they do not have adequate information to provide effective advice on concomitant cosmetic therapy. Although ample information is available in the literature on pharmaceutical treatment for cutaneous side-effects of chemotherapy, little is available for the concomitant use of dermatological skin-care products with medical treatments. The objective of this consensus study is to provide an algorithm for the appropriate use of dermatological cosmetics in the management of cutaneous toxicities associated with targeted chemotherapy such as epidermal growth factor receptor inhibitors and other monoclonal antibodies. These guidelines were developed by a French and German expert group of dermatologists and an oncologist for oncologists and primary care physicians who manage oncology patients. The information in this report is based on published data and the expert group’s opinion. Due to the current lack of clinical evidence, only a review of published recommendations including suggestions for concomitant cosmetic use was conducted.

Episkin: An in vitro model for the evaluation of phototoxicity and sunscreen photoprotective properties

Exposure to UV radiation has been shown to induce cutaneous biological changes and chemical modifications of exogenous compounds. The application of sunscreen limits UV-induced cutaneous injury. Besides damages can also be elicited by some chemicals following UV irradiation (phototoxic agents). The effects of UVA and UVB irradiation have been studied in vitro on a reconstituted epidermis (EPISKIN) for cytotoxicity (MTT conversion test) and release of a proinflammatory mediator, interleukin 1alpha. When compared with irradiated human keratinocyte monolayers, the results obtained with EPISKIN showed the protective function of the stratum corneum to UVB. Topical application of a UVB sunscreen directly on EPISKIN stratum corneum showed a concentration-dependent relationship between the active ingredients and UVB-induced damages evaluated by both parameters. When chlorpromazine was tested on EPISKIN, an increase in cytotoxicity and release of interleukin 1alpha followed UVA irradiation. A non-cytotoxic dose of 10 J/cm(2) of UVA induced a 20-fold decrease in the chlorpromazine IC50. The chlorpromazine-induced inflammatory reaction was also reflected by a more intense release of interleukin 1alpha in the underlying media of EPISKIN. Thus this proinflammatory mediator seems to be relevant as a phototoxic marker. The EPISKIN model may be a useful tool in the study of UV-induced cutaneous damage. The design of this study represents an advance in non-animal test development and could be of great interest in the determination of phototoxic or photoprotective effects of compounds in vitro.

Interest of corrective makeup in the management of patients in dermatology

BACKGROUND

Disfiguring dermatoses may have a significant impact on patients' quality of life, namely on their relationship with others, self image, and self esteem. Some previous studies have suggested that corrective foundation can improve the quality of life (QOL) of patients with facial dermatoses; in particular, in patients with acne vulgaris or pigmentary disorders.

OBJECTIVE

The aim of this prospective study was to evaluate the impact of the skin conditions of patients with various skin diseases affecting their face (scars, acne, rosacea, melasma, vitiligo, hypo or hyperpigmentation, lentigines, etc) on their QOL and the improvement afforded by the use of corrective makeup for 1 month after being instructed on how to use it by a medical cosmetician during an initial medical consultation.

METHODS

One hundred and twenty-nine patients with various skin diseases affecting the patients' face were investigated. The patients were instructed by a cosmetician on how to use corrective makeup (complexion, eyes, and lips) and applied it for 1 month. The safety of the makeup application was evaluated and the QOL was assessed via a questionnaire (DLQI) and using a 10-cm visual analog scale (VAS) completed before the first application and at the final visit. The amelioration of their appearance was documented by standardized photography.

RESULTS

No side effects occurred during the course of the study. A comparison of the standardized photographs taken at each visit showed the patients' significant improvement in appearance due to the application of corrective makeup. The mean DLQI score dropped significantly from 9.90 ± 0.73 to 3.49 ± 0.40 (P < 0.0001).

CONCLUSION

Our results suggest that dermatologists should encourage patients with disfiguring dermatoses to utilize appropriate and safe makeup to improve their appearance and their QOL. Corrective makeup can also complement the treatment of face dermatological diseases in order to improve patient's adherence.

Importance of treatment of skin xerosis in diabetes

BACKGROUND

Cutaneous complications are common in diabetes patients and previous studies have shown that diabetes can affect some biophysical skin characteristics. However, the interest of emollients in diabetes has never been clearly demonstrated; i.e. whether they are able to limit skin complications in diabetes patients.

OBJECTIVE

The aim of this study was to evaluate the tolerance and the effect of an emollient on patient with diabetes.

METHOD

Forty patients with diabetes applied the emollient twice daily for 1 month on one arm and one leg, in normal conditions.

RESULTS

A 1-month treatment with an emollient allows a similar skin hydration rate in diabetics to that in healthy people. This dry skin improvement is accompanied by a significant reduction in pruritus and desquamation, and a significant improvement in the skin barrier function.

CONCLUSION

Emollient treatment can be useful in the management of diabetes by limiting skin complications associated with elevated blood sugar.

Synthesis, Structure, Lattice Dynamics and Electrochemistry of Lithiated Manganese Spinel, LiMn2O4

We report synthesis, crystal structure, lattice dynamics, and electrochemical features of the lithiated manganese oxide spinel prepared through solid state reaction by careful selection of precursors and synthesis conditions. Elemental analysis shows that the material is a lithium-rich spinel phase. X-ray diffraction data and Rietveld refinement indicate formation of a single phase, impurity free, normal spinel of LiMn2O4. Lattice dynamics have been investigated by vibrational spectroscopy and group theoretical analysis has been carried out. Electrochemical performances of the lithiated spinel manganese oxide have been investigated, and the voltage profile of the cathode during lithium intercalation-deintercalation processes, close to equilibrium, has been obtained. The upper 4-volt plateau provides over 130 mA h/g with an excellent cyclability.

Synthesis, Characterization, and Electrochemical Performances of Substituted Layered Transition Metal Oxides. LiM1-yM'yO2. (M=Ni and Co. M'= B and AI)

The synthesis, characterization and electrochemical performances of lithiated nickelate and cobaltate doped with Al and B are reported. The synthesis involves solid state reaction between lithium hydroxide, nickel or cobalt oxides and several sources of aluminum and boron. Careful selection of precursors and heat treatment conditions are required to prepare single phase impurity free samples. X-ray diffraction and Rietveld refinement analysis indicate that the layered structure is preserved upon considerable substitution of aluminum and boron. X-ray diffraction line intensities and positions remained in good agreement with the space group. The IR spectra of the samples indicate formation of compressed CoO6 and NiO6, and elongated LiO6 octahedra. The IR vibrational mode of the LiO6 remains in the 200–300 cm-1 and the vibrational modes of the MO6 expand over 400–650 cm-1. Results of long charge-discharge cycling of the samples as cathode materials in lithium cells showed long cycle life. The capacity of the electrodes upon substitution were reduced almost linearly as the concentration of substitution was increased. The solubility limit for the formation of solid solutions upon substitution of Al and B in LiNiO2 and LiCoO2 was found to be around 25%. Specific capacities of the samples were between 120 to 160 mAh/g depending on the amount of substitution.

Vibrational Spectroscopic Studies of the Local Environment in 4-Volt Cathode Materials

We report the vibrational spectra of numerous 4-volt cathode materials, the transition metal oxides which are potential materials for advanced Li-ion batteries. They provide high specific energy density, high voltage, and remarkable reversibility for lithium intercalation-deintercalation process. Studied were carried out by Raman and FTIR spectroscopies. Oxides such as LiMn2O4, LiNiVO4, LiCoVO4 spinels, LiMeO2 (Me=Co, Ni, Cr) layered compounds and their mixed compounds have been investigated. The local environment of cations against oxygen neighboring atoms has been determined by considering tetrahedral and octahedral units building the lattice. Structural modifications induced by the intercalation-deintercalation process, by the cation substitution, or by the low-temperature preparation route are also examined. The results are compared with those of end members.

Photoprotection in moisturizers and daily-care products

During usual daily activities, an appropriate protection against solar UV exposure should prevent clinical, cellular and molecular changes potentially leading to photoaging. In skin areas regularly exposed to sun, UV-damage is superimposed to tissue degeneration resulting from chronological aging. It is, therefore, important to know if moisturizers and daily-care products containing UVA absorbers combined with UVB ones are able to prevent these skin damages. This review will summarize clinical studies evaluating this topic. These studies demonstrate that broad-spectrum protection in moisturizers or daily-care products can prevent the "silent" sub-erythemal cumulative effects of UVR from inadvertent sun exposure.

Randomized study comparing the efficacy and tolerance of a lipophillic hydroxy acid derivative of salicylic acid and 5% benzoyl peroxide in the treatment of facial acne vulgaris

BACKGROUND

New topical treatments for acne vulgaris are needed for patients who have tolerance problems with current treatments.

AIMS

To compare the efficacy and tolerance of a lipophillic derivative of salicylic acid (lipo hydroxy acid or LHA) containing formulation and 5% benzoyl peroxide in subjects with acne vulgaris.

METHODS

Eighty subjects with mild to moderate facial acne were randomized to receive either the LHA formulation twice a day or benzoyl peroxide once a day for 12 weeks. Efficacy and tolerance were evaluated at days 0, 28, 56 and 87. Results LHA formulation and benzoyl peroxide decreased the number of inflammatory lesions from baseline to week 12 by 44% and 47% and noninflammatory lesions by 19% and 23%, respectively. There was no statistically significant difference between the two treatments (P = 0.748; P = 0.445).

CONCLUSION

These results suggest that the LHA formulation could be a treatment option to consider in mild to moderate acne vulgaris patients that are intolerant to benzoyl peroxide.

Metal hydrides for lithium-ion batteries

Classical electrodes for Li-ion technology operate via an insertion/de-insertion process. Recently, conversion electrodes have shown the capability of greater capacity, but have so far suffered from a marked hysteresis in voltage between charge and discharge, leading to poor energy efficiency and voltages. Here, we present the electrochemical reactivity of MgH(2) with Li that constitutes the first use of a metal-hydride electrode for Li-ion batteries. The MgH(2) electrode shows a large, reversible capacity of 1,480 mAh g(-1) at an average voltage of 0.5 V versus Li(+)/Li(o) which is suitable for the negative electrode. In addition, it shows the lowest polarization for conversion electrodes. The electrochemical reaction results in formation of a composite containing Mg embedded in a LiH matrix, which on charging converts back to MgH(2). Furthermore, the reaction is not specific to MgH(2), as other metal or intermetallic hydrides show similar reactivity towards Li. Equally promising, the reaction produces nanosized Mg and MgH(2), which show enhanced hydrogen sorption/desorption kinetics. We hope that such findings can pave the way for designing nanoscale active metal elements with applications in hydrogen storage and lithium-ion batteries.

Evaluation of the effectiveness of a broad-spectrum sunscreen in the prevention of chloasma in pregnant women

BACKGROUND

Chloasma, or melasma, is a pigmentary disorder that can affect between 50% and 70% of pregnant women. During pregnancy, chloasma does not require any particular treatment beside the use of an effective sunscreen and avoiding the use of any photosensitizing products or inappropriate skin care routine. However, there exist very few studies related to the benefits of sunscreens to prevent this dermatosis.

OBJECTIVE

The aim of this study was to assess the role of a broad-spectrum sunscreen in the prevention and treatment of chloasma in pregnant women.

METHODS

We tested the effectiveness and tolerance of a sunscreen composition (SPF 50+, UVA-PF 28) during a 12-month clinical trial on 200 parturients.

RESULTS

The 'excellent' tolerance of the sunscreen under evaluation was confirmed. Out of 185 patients who completed the study, only five new cases of chloasma were noted, an occurrence of 2.7%, which is much lower than the 53% previously observed in an usual condition study (same investigators, same geographical area and same time frame). In addition, the clinical effectiveness of the evaluated sunscreen was judged 'excellent' by the majority of parturients and by the research dermatologists during all the consultations. It is also worth noting that at 6 months, a clinical improvement was observed in 8 out of 12 volunteers who were affected by a pre-existing chloasma observed during their inclusion visit. Colorimetric measurements showed that, at the end of their pregnancy, the parturients' skin was, on average, significantly lightened (increase of parameter L* in 38% cases) and less pigmented (reduction of parameter b* in 50% cases); thus, resulting in a significantly lighter skin colour (increase of ITA degrees in 69% cases) compared to their inclusion visit.

CONCLUSIONS

This study clearly demonstrates the effectiveness of the well-tolerated broad-spectrum sunscreen evaluated, in the prevention of the development of chloasma in pregnant women.

Polysialylation of NCAM is upregulated by hyperthermia and participates in heat shock preconditioning-induced neuroprotection

"Brain tolerance"--a phenomenon in which a subtoxic challenge confers resistance to subsequent brain injuries--provides an ideal opportunity for investigating endogenous neuroprotective mechanisms. We investigated the potential role of the polysialylated (PSA) form of neural cell adhesion molecule (NCAM), which is thought to play a key role in plasticity. In a model where prior exposure to heat shock protects against kainate-induced cell damage in the hippocampus, we show that hyperthermia upregulates PSA-NCAM expression for at least 1 week, without affecting neurogenesis. Pharmacological manipulation of heat shock protein (HSP) expression demonstrates a tight positive link between HSP70 and PSA-NCAM. Finally, the presence of PSA was functionally linked to brain tolerance, as protection against kainate-induced cell death by heat shock pre-exposure was abolished in the absence of NCAM polysialylation. The upregulation of PSA-NCAM by hyperthermia may have a significant impact on hippocampal plasticity, permitting induction of the complex molecular cascade responsible for neuroprotection.