Long-term Safety and Effectiveness of Hyaluronic Acid Fillers Correcting Nasolabial Folds in Chinese Patients.

Background: Soft-tissue fillers, specifically hyaluronic acid fillers, can reduce many signs of aging by treating the associated loss of subcutaneous fat and midfacial contour deficiencies. The objective of this study was to investigate whether the effectiveness and safety of Belotero Volume Lidocaine (BVL) compared with Restylane (RES, control) is noninferior in the treatment of severe nasolabial folds (NLFs) in Chinese patients. Methods: This was a prospective, randomized, controlled, split-face clinical study. Overall, 220 Chinese patients of both sexes with symmetrical NLFs of severe intensity (grade 4) on the Wrinkle Severity Rating Scale (WSRS) were treated with both fillers. Treatment outcomes were assessed by the WSRS, and other scales, at multiple time points up to 18 months postinjection. The co-primary effectiveness outcomes were based on the blinded evaluator ratings of NLFs according to the WSRS scale after 6 and 12 months. Adverse events were assessed during the whole study and patients' pain sensation at three time points after injection. Results: Noninferiority of BVL versus control based on the WSRS was demonstrated at month 6 and month 12. Response rates were slightly higher for BVL than control at all time points, and BVL had a sustained effect until month 18. Pain sensation scores were significantly lower for BVL compared with control. The incidence rates of treatment-related AEs were low and very similar for both treatments. Conclusions: This study demonstrates that BVL is a safe, long-lasting, and effective treatment to correct severe NLFs in Chinese patients while being noninferior to the control device.

Chlorinated polyhedral selenaboranes revisited by joint experimental/computational efforts: the formation of closo-1-SeB9Cl9 and the crystal structure of closo-SeB11Cl11.

The recent success in the formation of chlorinated telluraboranes and the reactivities of pnictogenaboranes prompted us to re-examine the vacuum co-pyrolysis of B2Cl4 with Se2Cl2 at various molar ratios and temperatures in order to search for the generation of other polyhedral selenaboranes than closo-SeB5Cl5 (1a) and closo-SeB11Cl11 (1b), the latter being observed earlier. Interestingly, a new compound with the elemental composition SeB9Cl9 (2) was detected, this time by high- and low-resolution mass spectrometry. Further characterization by 1- and 2-D 11B-NMR spectroscopy suggests that 2 should adopt a closed bicapped square-antiprismatic geometry with selenium at the apical position. Moreover, vacuum sublimation gave suitable crystals of 1b, which were subjected to single-crystal X-ray structure determination. Crystallographic data analysis confirmed that 1b, consistent with its 26 skeletal electron count, adopts a distorted icosahedral structure close to the symmetry of C5v. Computations at the DFT-D3 level have revealed that 33% of the total computed binding motifs in the grown 1b crystals are due to the very strong chalcogen bonding. Moreover, SAPT decomposition has shown that the bonding motifs in the crystals are stabilized mainly by dispersion and electrostatic terms. Homodecoupling and high resolution 11B NMR and 77Se NMR experiments have resolved both coupling constants 1J(11B11B) and 1J(77Se11B) as well as the 77Se chemical shift of 1a and 1b, which are in reasonable agreement with the corresponding computed values. The computed 11B chemical shifts of 2 were determined by the well-established DFT/GIAO/NMR structural tool based on its B3LYP/6-311+G** internal coordinates. They agree well with the experimental values and provide a good representation of the molecular structure of 2 in solution. The extraordinary downfield 11B NMR chemical shift of B(10) in 2 has been ascribed to the intensive paramagnetic contribution to the shielding tensor in this bicapped square-antiprismatic motif. Calculations of the synproportionation free energies of smaller (n - 1) closo-selenaboranes with larger-sized (n + 1) ones support the extraordinary stability of octahedral, bicapped square-antiprismatic and icosahedral closo motifs in the SeBnCln family (n = 4-12).

Norwegian hourly residential electricity demand data with consumer characteristics during the European energy crisis.

This dataset was collected to understand how Norwegian households responded to the electricity price shock due to the European energy crisis. It consists of consumer characteristics and their self-reported responses to the extraordinarily high electricity prices which were collected with a survey of 4,446 consumers. The consumer characteristics contain socio-demographic information, such as income, age, education, number of residents, residence type, residence size, and how conscious the respondents were about their electricity consumption. Furthermore, major electricity-consuming appliances were identified, such as whether the residents had an electric vehicle and how they heated their homes, and if they had a dynamic electricity price contract. In addition, the dataset includes hourly metered electricity consumption data covering October 2020 to March 2022 from a subset of 1,136 residential consumers of the surveyed households, the total hourly residential electricity consumption per Norwegian bidding area from July 2019 to July 2022, and the hourly day-ahead electricity prices. These data are interesting to researchers that aim to gain insight into the electricity consumption behaviour of the residential sector and the impact of different socio-demographic variables.

A rich dataset of hourly residential electricity consumption data and survey answers from the iFlex dynamic pricing experiment.

The iFlex field experiment was conducted to understand if and how households change their power consumption in response to variable hourly electricity prices. This experiment was conducted in several Norwegian regions, and various price signals were tested over two winter periods from early 2020 to spring 2021. The resulting dataset includes hourly electricity consumption data of all participating households and answers to three surveys about household characteristics such as electric appliances, living conditions, socio-demographic variables, and their willingness to be flexible. In addition, temperature data are added to the dataset from public sources. This rich dataset can be used to analyse households' demand flexibility potential in-depth. Furthermore, subgroups, such as low-income households or highly electrified households with electricity as a primary heating source, can be investigated to enhance the understanding of how these are affected by variable power prices.

Management of psoriatic arthritis by dermatologists - a German nationwide survey.

BACKGROUND AND OBJECTIVES: Psoriatic arthritis (PsA) warrants early diagnosis and treatment for optimal results. This study aimed to elucidate routine monitoring activities for PsA with concurrent psoriasis (PsO) by dermatologists to gather data on how conditions for optimal treatment are ensured. PATIENTS AND METHODS: This non-interventional, prospective, epidemiological, cross-sectional study (2016-2019) included patients with confirmed PsA from dermatologists. Descriptive statistics were conducted for center and patient characteristics as well as for data of PsA monitoring and treatment stratified by different center types. RESULTS: 212 patients from 34 office-based physicians, five non-university hospitals, and nine university hospitals were included. The majority of the PsA patients were diagnosed by a rheumatologist (> 55% in each center type) at an early or intermediate stage (> 59%). Treatment was initiated most frequently by a dermatologist (office-based physicians: 69.6%, hospitals: 60.9%, university hospitals: 82.9%). Patients were treated with biologics more frequently in university hospitals (single therapy: 43.9%, in combination with systemic therapy: 26.8%) compared to private practices (single: 44.6%, combination: 13.5%) and non-university hospitals (single: 34.8%, combination: 8.7%). CONCLUSIONS: As PsA diagnosis was performed most frequently by rheumatologists whereas treatment was primarily initiated by dermatologists, an optimal collaboration between these specialists is crucial.

Earth beyond six of nine planetary boundaries.

This planetary boundaries framework update finds that six of the nine boundaries are transgressed, suggesting that Earth is now well outside of the safe operating space for humanity. Ocean acidification is close to being breached, while aerosol loading regionally exceeds the boundary. Stratospheric ozone levels have slightly recovered. The transgression level has increased for all boundaries earlier identified as overstepped. As primary production drives Earth system biosphere functions, human appropriation of net primary production is proposed as a control variable for functional biosphere integrity. This boundary is also transgressed. Earth system modeling of different levels of the transgression of the climate and land system change boundaries illustrates that these anthropogenic impacts on Earth system must be considered in a systemic context.

A Multicenter Noninferiority Study Comparing Safety and Effectiveness of Hyaluronic Acid Fillers for Correction of Nasolabial Folds in Chinese Subjects.

Hyaluronic acid fillers are the preferred choice for minimally invasive facial volume restoration. In this study, a split-face design was used to compare the effectiveness and safety results of Belotero Balance Lidocaine (BEL) and Restylane (RES, control) to investigate whether BEL is noninferior compared with RES in nasolabial fold (NLF) correction. Methods: This was a prospective, controlled clinical study in Chinese subjects. Subjects with symmetrical moderate NLFs according to the Wrinkle Severity Rating Scale were randomized to receive BEL in one NLF and RES in the other. The primary objective was to investigate whether BEL is noninferior compared with RES after being injected mid-dermally in moderate NLFs after 6 months. Secondary objectives included responses at other visits and pain sensation. Treatment-emergent adverse events (TEAEs) were assessed. Results: A total of 220 subjects were enrolled. The Wrinkle Severity Rating Scale response rates at month 6 were 62.9% for BEL versus 64.9% for RES, demonstrating noninferiority. The secondary endpoints supported this. Significantly reduced pain scores were observed for BEL versus RES. For both products, injection site nodule and bruising were the most frequent treatment-emergent adverse events at the injection site. All treatment-related treatment-emergent adverse events were mild. Conclusions: The study showed that BEL is effective and well tolerated for correction of moderate NLFs in Chinese subjects. Noninferiority of BEL was demonstrated compared with RES, and regardless of applied pain treatment, a further reduction in injection pain was observed in BEL.

Reactivity of Perhalogenated Octahedral Phospha- and Arsaboranes toward THF: A Joint Experimental/Computational Study.

Reactions of the perhalogenated polyhedral pnictogenaboranes closo-1,2-Pn2B4Hal4 (Pn = P, As; Hal = Cl, Br) with Lewis bases are presently being studied with a focus on rationalizing the sites of nucleophilic attacks on clusters bearing σ-holes. These σ-holes are localized both on pnictogens and, for Hal = Br, on bromine atoms, as revealed by electrostatic potential (ESP) and intrinsic bond orbital (IBO) analyses. Surprisingly, the attack of the cyclic ether THF on closo-1,2-Pn2B4Br4 does not occur on the site with the largest positive partial charge, centered in the middle of the pnictogen-pnictogen vector. Instead, presumably promoted by the positivated bromine substituents, THF inserts into the boron-bromine bonds of the negatively charged boron atoms opposite to the pnictogen atoms to form 4-(4-bromobut-1-oxy)-closo-1,2-Pn2B4Br3 (1-PB and 1-AsB) and 4,6-(4-bromobut-1-oxy)2-closo-1,2-Pn2B4Br2 (2-PB and 2-AsB). 11B and 31P chemical shift computations at various levels support the assignments of the signals, which reflect the correctness of the molecular geometries in solutions. The Lewis-acidic perchlorinated analogues closo-1,2-P2B4Cl4, closo-1,2-As2B4Cl4, and the mixed closo-1,2-AsPB4Cl4 bear negative charges. These negative charges are revealed by the Vs,max values when computing the electrostatic potentials both on the boron and the chlorine atoms. Due to this negative charge, the analogues do not react with THF unless they are heated above 66 °C, where they slowly decompose to borate esters B(OR)3 without the formation of concrete intermediates. The evaluation of 31P NMR data of 1-PB has allowed the experimental determination of the coupling constant 1J(31P(1), 31P(2)) = |143| Hz in a closo-diphosphaborane for the first time, which agrees well with the computed value of -178 Hz. The pioneering joint experimental vs computational interpretation of 31P NMR spectra in the area of boron cluster chemistry was decisive for the structural characterization of 1-PB and 2-PB.

Microinjections with hyaluronic acid in combination with glycerol: How do they influence biophysical viscoelastic skin properties?

BACKGROUND: Skin quality improvement with hyaluronic acid microinjections is increasing as a clinical treatment indication and as a scientific issue. This present study assessed changes in biomechanical viscoelastic skin properties after microinjections with the skin quality booster CPM-HA20G (Belotero Revive). MATERIALS AND METHODS: Fifteen subjects have been randomized in a 2:1 ratio to receive either three treatments (total 3 ml per side) or a single-dose treatment (total 1.5 ml per side) with CPM-HA20G at dermal level into the lower cheeks via microinjections. Treatments were provided 4 weeks apart. Biophysical measurements were performed describing the viscoelastic skin properties and the underlying skin structure. The measurements were performed before injection (week 0) and on follow-up visits 4, 8, 16, 24, and 36 weeks after the last injection treatment. RESULTS: One (p = 0.028) as well as three (p = 0.003) consecutive treatments with CPM-HA20G improved statistically significant skin firmness (R0). For the multiple-treatment group improved significant differences were observed for skin fatigue (R3; p = 0.007) and skin density (p = 0.017) with stable skin thickness levels (p > 0.05), too. There were zero-to-weak correlations between skin thickness and biomechanical skin properties (R0, rs  = 0.084; R3, rs  = 0.093). CONCLUSION: Overall, microinjections with CPM-HA20G improved biomechanical viscoelastic skin properties with a stronger and more pronounced effect in the multiple-treatment group. The observed changes may explain some of the skin quality improvements observed after treatment with CPM-HA20G.

Safety of Cohesive Polydensified Matrix Cross-Linked Hyaluronic Acid Volumizing Gel in Temporal Hollows and Cheeks: A Prospective, Open-Label, Postmarket Study.

BACKGROUND: Facial aging is characterized by volume loss and progressive hollowing of temples and cheeks. Biodegradable filler materials are preferred over nonabsorbable materials; of these, hyaluronic acid (HA) fillers are the most often used because of their favorable effectiveness and safety profile. OBJECTIVE: To confirm the safety and effectiveness of Cohesive Polydensified Matrix (CPM)-HA26 gel in the treatment of volume deficiency. METHODS: Subjects received up to 2 treatments in the temples and/or cheeks. A blinded investigator assessed improvement according to the Merz Temple Volume Scale (MTVS) and Merz Cheek Fullness Assessment Scale (MCFAS). Subjects were followed for 48 weeks after the last treatment. RESULTS: In total, 87 healthy subjects were enrolled. The proportion of subjects achieving at least a 1-grade improvement on MTVS and/or MCFAS was above 70% for each (MTVS: Weeks 4, 24, and 48 = 95.4%, 94.2%, and 77.0%; MCFAS: Weeks 4, 24, and 48 = 92.3%, 83.1%, and 71.8%). Based on MTVS and MCFAS scores at Visit 5, improvement remained visible at up to 48 weeks. No treatment-related serious AEs occurred. CONCLUSION: CPM-HA26 demonstrated both a favorable safety and effectiveness profile, with improvement in facial volume evident for up to 48 weeks. It was well tolerated and had a positive, long-lasting effect.

Unraveling the Way Acetaldehyde is Formed from Acetylene: A Study Based on DFT.

Acetylene hydratase (AH) of Pelobacter acetylenicus is a tungsten (W)-containing iron-sulfur enzyme that catalyzes the transformation of acetylene to acetaldehyde, the exact/true reaction mechanism of which is still in question. Scientists utilized different computational approaches to understand the reaction mechanism of acetylene hydration. Some identified it as a multistep (4-16) process that starts with the displacement of a water molecule present at the active site of AH with acetylene. However, some said that there is no need to displace water with acetylene at the active site of AH. As the reaction mechanism for the conversion of acetylene to acetaldehyde is still controversial and needs to be investigated further, DFT studies were performed on the model complexes derived from the native protein X-ray crystal structure of AH. Based on the computational results, here we are proposing the nucleophilic reaction mechanism where the water (Wat1424) molecule is coordinated to the W center and Asp13 is assumed to be in an anionic form. The Wat1424 molecule is activated by W and then donates one of its protons to the anionic Asp13, forming the W-bound hydroxide and protonated Asp13. The W-bound hydroxide then attacks the C1 atom of acetylene together with the transfer of a proton from Asp13 to its C2 atom, resulting in the formation of a vinyl alcohol intermediate complex. The energy barrier associated with this step is 14.4 kcal/mol. The final, rate-limiting, step corresponds to the tautomerization of the vinyl alcohol intermediate to acetaldehyde via intermolecular assistance of two water molecules, associated with an energy barrier of 18.9 kcal/mol. Also, the influence of the metal on the hydration of acetylene is studied when W is replaced with Mo.

Facial Skin Revitalization with Cohesive Polydensified Matrix-HA20G: Results from a Randomized Multicenter Clinical Study.

BACKGROUND: There is a growing interest in the application of hyaluronic acid (HA) derivatives in skin quality improvement. The aim of this study was to confirm safety and effectiveness of cohesive polydensified matrix-hyaluronic acid + glycerol (CPM-HA20G; Belotero Revive) in revitalization of early-onset photodamaged facial skin. METHODS: A total of 159 subjects with early signs of facial photodamaged skin were randomized in a 2:1 ratio to multiple- or single-dose treatment with CPMHA20G. Effectiveness assessments included biophysical measurements of skin hydration; elasticity, firmness, and roughness; investigator- and subject-assessed Global Aesthetic Improvement Scales; and FACE-Q Skin Changes and Treatment Satisfaction questionnaires. RESULTS: In both treatment groups, skin hydration improved from baseline to all follow-up visits in subjects with dry or very dry skin. This improvement was significant at week 16 after initial treatment in the multiple-dose group (P = 0.0013). Investigator- and subject-reported outcomes showed that the majority of subjects across all skin hydration types benefited from treatment, with higher satisfaction rates observed in the multiple-dose group. According to investigator-assessed Global Aesthetic Improvement Scale, 90.7% of subjects at week 12 in the multiple-dose and 74.6% of subjects at week 4 in the single-dose group were rated as at least "improved." All related treatment-emergent adverse events were transient, expected injection-site reactions of mild to moderate intensity. CONCLUSIONS: Effectiveness of CPM-HA20G for skin hydration in subjects with dry or very dry skin was demonstrated up to 9 months after last injection. Overall, CPM-HA20G demonstrated effective and safe use in facial skin revitalization among subjects with early-onset photodamaged skin.

Safety and Performance of Etermis 3 and 4 in Wrinkles/Folds Treatment and Facial Volume Enhancement: A Prospective, Evaluator-Blinded, Open-Label Study.

BACKGROUND: Facial aging is characterized by increased prominence of nasolabial folds (NLFs), marionette lines, and thinning of the lips. Cross-linked hyaluronic acid injection is a very effective method for the temporary correction of these areas. OBJECTIVE: To confirm the clinical performance and the safety of Etermis 3 (ET3) and/or Etermis 4 (ET4) in the treatment of moderate and severe wrinkles/folds, as well as lip volume enhancement. METHODS: Subjects were treated in at least two facial areas (NLFs, marionette lines, lips). ET3 was used in facial moderate wrinkles while ET4 was used in severe facial skin volume loss. An optional touch-up 1 month after treatment was possible. A blinded investigator assessed improvement on Merz Aesthetic Scales (MAS). Subjects were followed-up for 12 months after the last treatment. RESULTS: In total, 154 healthy subjects were enrolled. The proportion of subjects achieving ≥1 score improvement in MAS after treatment was above 60% for ET4 (Month 6/7: NLFs 94.9% and marionette lines 81.4%, p≤0.0004; Month 3/4: lips 63.0%, p=0.39) and ET3 (Month 6/7: marionette lines 79.4%, p=0.0005; Month 3/4: lips 65.5%, p=0.31). Facial improvement was still visible at Month 12/13 for ET4 (NLFs ≥76.6%, marionette lines ≥61%, lips ≥36%) and ET3 (marionette lines ≥50% and lips ≥21.9%). No treatment-related serious AEs occurred. The most frequent AEs were injection-site reactions. CONCLUSION: Etermis 3 and Etermis 4 demonstrated good clinical performance and safety for NLFs and marionette lines volume enhancement for up to 12 months. Both products can also be used safely to treat lips for volume augmentation.

Probing Trions at Chemically Tailored Trapping Defects.

Trions, charged excitons that are reminiscent of hydrogen and positronium ions, have been intensively studied for energy harvesting, light-emitting diodes, lasing, and quantum computing applications because of their inherent connection with electron spin and dark excitons. However, these quasi-particles are typically present as a minority species at room temperature making it difficult for quantitative experimental measurements. Here, we show that by chemically engineering the well depth of sp3 quantum defects through a series of alkyl functional groups covalently attached to semiconducting carbon nanotube hosts, trions can be efficiently generated and localized at the trapping chemical defects. The exciton-electron binding energy of the trapped trion approaches 119 meV, which more than doubles that of "free" trions in the same host material (54 meV) and other nanoscale systems (2-45 meV). Magnetoluminescence spectroscopy suggests the absence of dark states in the energetic vicinity of trapped trions. Unexpectedly, the trapped trions are approximately 7.3-fold brighter than the brightest previously reported and 16 times as bright as native nanotube excitons, with a photoluminescence lifetime that is more than 100 times larger than that of free trions. These intriguing observations are understood by an efficient conversion of dark excitons to bright trions at the defect sites. This work makes trions synthetically accessible and uncovers the rich photophysics of these tricarrier quasi-particles, which may find broad implications in bioimaging, chemical sensing, energy harvesting, and light emitting in the short-wave infrared.

Facial skin revitalization with CPM®-HA20G: an effective and safe early intervention treatment.

BACKGROUND: Hyaluronic acid (HA) fillers are popular for the treatment of signs of facial skin aging. OBJECTIVE: The objective of this study was to confirm the performance and safety of a new cohesive polydensified matrix HA filler ([CPM®-HA20G, Belotero Revive®, lidocaine-free], Merz Pharmaceuticals GmbH, Frankfurt, Germany) for the treatment of early signs of facial skin aging by use of biophysical measurements as well as subject and investigator satisfaction. METHODS: Twenty-five healthy female subjects with signs of facial skin aging were enrolled in this open-label, rater-blinded, observational post-market clinical follow-up study, and received 20 micropuncture treatments of 50 µL CPM®-HA20G each into the lower cheek area at three injection visits 4 weeks apart. Objective biophysical assessments were conducted to demonstrate effects on viscoelastic properties of the skin, surface roughness, tone and radiance, and hydration, at baseline and at all follow-up visits up to 36 weeks. RESULTS: CPM®-HA20G significantly increased gross elasticity of the skin (at weeks 9 and 12), skin firmness (up to week 24), skin tone and radiance and skin hydration (all up to 36 weeks). Significant reduction of skin fatigue (up to 9 weeks), skin roughness (up to 28 weeks), and redness (up to 36 weeks) was also observed. Subjects and blinded investigator were highly satisfied with the treatment outcomes. The treating investigator reported a high level of satisfaction with the ease of injection and the clinical performance of the device. Moreover, data demonstrated a good safety profile of the device. CONCLUSION: CPM®-HA20G is considered to be an effective and safe HA injectable for skin revitalization in patients suffering from signs of skin aging and loss of skin elasticity. It seems to be a perfect early intervention approach in patients that do not need volumizing treatment and a combination approach in older patients with more pronounced aging.

The influence of lanthanide-(III)-nitrates on adsorbed monolayers of dodecylphosphorylcholine at the air-water interface.

Adsorption layers at the air-water interface formed from the soluble zwitterionic surfactant dodecylphosphorylcholine (DPC) serving as a soluble model substance for phospho-lipids were characterized with respect to their equilibrium and dynamic surface properties. To clarify the effect of ionic interactions with electrolyte present in the bulk phase, surface rheological properties upon addition of Ce(NO3)3 and Yb(NO3)3 were determined. In order to account for the surface activity of the nitrate ion, comparative measurements using NaNO3 were carried out additionally. Further experimental information on the bulk hydration characteristics of the aqueous solutions was obtained using dielectric relaxation spectroscopy (DRS). A possible mechanism causing the deviating surface dilatational modulus E in terms of ion specificity is suggested.

Assessment of Melanogenesis in a Pigmented Human Tissue-Cultured Skin Equivalent.

BACKGROUND: Organotypic tissue-cultured skin equivalents are used for a broad range of applications either as possible substitute for animal tests or for transplantation in patient-centered care. AIMS: In this study, we implemented melanocytes in a tissue-cultured full-thickness skin equivalent, consisting of epidermis and dermis. The versatility of this skin-like model with respect to pigmentation and morphological criteria was tested. MATERIALS AND METHODS: Pigmented skin equivalents were morphologically characterized, and melanogenesis was evaluated after treatment with kojic acid - a tyrosinase inhibitor and forskolin - a well-known activator of the cyclic adenosine 3,5-monophosphate pathway. Pigmentation was measured either by determination of the extinction at 400 nm after melanin extraction with KOH correlated to a melanin standard curve or by reflectance colorimetric analysis, monitoring reflectance of 660 nm and 880 nm emitting diodes. RESULTS: The morphological analysis revealed characteristic epidermal stratification with melanocytes located at the basal layer. Stimulation with forskolin increased the pigmentation, whereas treatment with kojic acid caused bleaching. CONCLUSION: The present study demonstrates that the herein-introduced organotypic tissue-cultured skin equivalent is comparable to the normal human skin and its versatility in tests regarding skin pigmentation. Therefore, this model might help understand diseases with dysfunctional pigmentation such as melasma, vitiligo, and postinflammatory hyperpigmentation.

Simultaneous measurement of the thickness and the lifetime of a foam lamella.

Despite the important role of foams in industrial applications, few methods for determining the stability are present. By extending the existing light reflection-based apparatus, additional information about a single foam lamella can be obtained. Evaluation of these data delivers insight into the thinning process of the lamella. The potential of this technique is shown for the analysis of two surfactants with different head group lengths (Lutensol XP 100 and Lutensol XP 140).

The surface rheological signature of the geometric isomers of an azobenzene-surfactant.

The equilibrium and dynamic surface properties of a photosensitive azobenzene-surfactant subject to illumination with UV and Vis-light leading to the respective geometric cis- and trans-isomers were studied. The adsorption layers formed by the soluble surfactant were characterized by pendant drop tensiometry and surface rheology using the oscillating bubble technique. Aqueous solutions corresponding to the geometric isomers could clearly be distinguished in terms of both their equilibrium and dynamic surface properties. The frequency dependence of the surface dilatational modulus could be described by the extended Lucassen-van den Tempel (LvdT)-model. These findings can be interpreted in terms of the changes of the dipole moment. Furthermore, they shed some light on the relation between the molecular structure and macroscopic properties of the adsorption layer.