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Inhalation toxicity testing of particulate materials is mandated for classification. According to CLP, particulate materials should be tested as marketed and many particulate materials are marketed as non-respirable particles. However, OECD TG 413 requires exposure to particle sizes that are respirable and reach the alveoli. The requirement for exposure of rats to respirable particles is thus in contrast to CLP and requires the application of high shear forces. The exposure to artificially small particles causes a number of issues that hamper the interpretation of the results of the testing. These issues are aerosol altering in the exposure system, assessment of the adversity of the inflammatory lung responses, inclusion of recovery groups, and extrapolation of the results to humans exposed under occupational condition. In addition, effects of many particulate materials after testing according to OECD 413 are not intrinsic properties, but a general reaction of the lung to the deposited material, show very similar NOAECs for chemical diverse materials, and often are completely reversible.

In a subchronic (13-week) inhalation toxicity study with a terminal sacrifice (after 13 weeks inhalation) and several recovery period sacrifices (13, 26, 39, and 52 weeks), the effects of AEROSIL® 200 (pyrogenic synthetic amorphous silica (SAS)), AEROSIL® R 974 (surface-treated pyrogenic SAS), and SIPERNAT® 22 S (precipitated SAS) were tested in rats at multiple dose levels. The aforementioned materials are all SAS products. A comparative group of animals was exposed to quartz dust. This study attempts to reexamine the lung tissues originally evaluated in a study published by Reuzel et al. using the current standards. To reach a high level of credibility, the results of the reevaluation were subsequently examined by a pathology working group (PWG). In particular, the reevaluating pathologist and the PWG concluded that, even though quartz (crystalline silica) persisted, induced alterations in the lungs following 13 weeks of exposure to amorphous silicas were reversible following 52 weeks of recovery. A long-term adversity has not been established with SAS products. However, quartz dust damages lungs significantly by causing pulmonary fibrosis.

Volume loss in facial adipose tissue plays a critical role in the aesthetics of facial aging. Furthermore, the facial adipose system is a complex network of distinct compartments, and a detailed understanding of these compartments is essential for optimal facial volume restoration.To review the facial adipose system, age-related changes, and the role of volume restoration products for facial rejuvenation.Publications including deceased donors' dissection studies and more recent studies using computed tomography were reviewed to provide an up-to-date understanding of the facial adipose system anatomy and age-related changes. Current volume restoration treatment options including hyaluronic acid, calcium hydroxylapatite, and poly-L-lactic acid are discussed.Facial aging is associated with volume loss in superficial and deep adipose compartments, including those of the forehead, cheek, lip, chin, and jowl areas. Volume restoration products can be used to address the age-related changes of the facial adipose compartments.Understanding the complex network of facial adipose compartments and their age-related changes allows for the optimal use of injectable volume restoration products for facial rejuvenation that can be customized to the anatomical needs of each patient.

BACKGROUND Botulinum toxins are used for facial rejuvenation. OBJECTIVE To investigate the efficacy, patient satisfaction, and skin physiology after incobotulinumtoxinA treatment of the upper face. MATERIALS AND METHODS Thirty women aged 35 to 55 were enrolled in this single-center prospective 16-week study. Patients and an investigator blinded to visit number assessed wrinkle severity after incobotulinumtoxinA treatment of glabellar, periorbital, and forehead lines using Validated Assessment Scales at Days 0 (baseline), 2, 7, 14, 28, and 112. Responder rates (for each region) and mean wrinkle scores (whole upper face) were calculated. Treatment satisfaction was self-assessed by questionnaire. Transepidermal water loss (TEWL), stratum corneum hydration, and skin pH were measured to assess skin barrier function. RESULTS Wrinkle severity decreased rapidly after treatment. Responder rates generally peaked at Days 7 to 14. At 112 days, mean scores remained significantly lower than baseline (p < .05). Patients were significantly more satisfied with their appearance after treatment; most felt "younger" and "more attractive" (p < .05). Transepidermal water loss decreased significantly throughout (p < .05), and stratum corneum hydration increased. No treatment-related adverse events occurred. CONCLUSION IncobotulinumtoxinA rapidly improved wrinkle severity, and improvements were maintained for up to 112 days. Increased stratum corneum hydration and reduced TEWL may improve skin quality. IncobotulinumtoxinA was well tolerated and improved patients' self-perception.

In recent years, a number of modalities have become available for the noninvasive reduction of adipose tissue, including cryolipolysis, radiofrequency, low-level laser, and high-intensity focused ultrasound. Each technology employs a different mechanism of action to cause apoptosis or necrosis of the targeted adipocytes. Among these technologies, cryolipolysis has not only been commercially available for the longest time, but has also been best researched including in vitro and animal models and randomized controlled clinical trials in humans. The principle behind cryolipolysis exploits the premise that adipocytes are more susceptible to cooling than other skin cells. The precise application of cold temperatures triggers apoptosis of the adipocytes, which invokes an inflammatory response and leads to slow digestion by surrounding macrophages. In clinical studies, cryolipolysis was shown to reduce subcutaneous fat at the treatment site by up to 25% after one treatment. Improvements were seen in 86% of treated subjects. At 73%, the patient satisfaction rate is higher than with other technologies used for noninvasive lipolysis. Cryolipolysis has been proven to be a very safe method for body contouring, and is accomplished with only minimal discomfort. Expected side effects are temporary erythema, bruising, and transient numbness that usually resolve within 14 days after treatment. With a prevalence of 0.1%, the most common complaint is late-onset pain, occurring 2 weeks post-procedure, which resolves without intervention. Although no procedure has been accepted as the gold standard for noninvasive body contouring as yet, cryolipolysis is considered to be both safe and efficient with a high patient satisfaction rate.

The cosmetic use of botulinum toxin (BoNT) is the most common cosmetic procedure performed in the world today. Common adverse events seen in the aesthetic use of the BoNT include swelling, localized bruising, headaches, injection site discomfort, excessive muscle weakness, and unintended paresis of adjacent muscles. BoNT has a wide array of cosmetic uses, including treatment of glabellar lines, chemical browlift, forehead wrinkles, periorbital, and perioral lines. The future formulations and applications of BoNT type A will be plentiful, and are exciting to consider.

An article titled "Current issues in dermatologic office-based surgery" was published in the JAAD in October 1999 (volume 41, issue 4, pp. 624-634). The article was developed by the Joint American Academy of Dermatology/American Society for Dermatologic Surgery Liaison Committee. A number of subjects were addressed in the article including surgical training program requirements for dermatology residents and selected advances in dermatologic surgery that had been pioneered by dermatologists. The article concluded with sections on credentialing, privileging, and accreditation of office-based surgical facilities. Much has changed since 1999, including more stringent requirements for surgical training during dermatology residency, and the establishment of 57 accredited Procedural Dermatology Fellowship Training Programs. All of these changes have been overseen and approved by the Residency Review Committee for Dermatology and the Accreditation Committee for Graduate Medical Education. The fertile academic environment of academic training programs with interaction between established dermatologic surgeons and fellows, as well as the inquisitive nature of many of our colleagues, has led to the numerous major advances in dermatologic surgery, which are described herein.

Background/Purpose: Modern men have changed their beauty and grooming habits, which has resulted in an increasing demand for cosmetics for men. However, very little information is available about the dermatological needs of male skin. Therefore, the aim of this present clinical study was to conduct the first systematic assessment of the skin physiology of men with special attention to lifetime changes. Methods: A total of 150 healthy male subjects (aged 20-70 years) were selected following strict criteria, including age, sun behavior and smoking habits. Transepidermal water loss (TEWL), hydration level, sebum production and pH values were measured with worldwide-acknowledged biophysical measuring methods at the forehead, cheek, neck, volar forearm and dorsum of hand. Results: TEWL and sebum production vary by localization, but generally not with increasing age, whereas stratum corneum (SC) hydration decreases significantly at the face and neck. The greatest decrease was assessed at the forehead. Skin surface pH significantly increases with aging in the face. Conclusion: The present study assigns for the first time systematic reference values for standardized biophysical measuring methods and localizations reflecting the skin physiology of men in relation to age. The results show that the physiology of male skin partly changes with aging. While SC hydration and skin surface pH are affected by the subject's age, TEWL and sebum production show only minor variations.

Background The assessment of wrinkle severity is an important evaluation criterion to determine the efficacy of aesthetic treatments. Aim of the present study was to compare Validated Assessment Scales (VAS) and 3D fringe projection (PRIMOS®) for the evaluation of facial wrinkles in men and to determine standard values for each level of the VAS. Methods 150 male subjects (20 to 70 years) were selected following strict criteria. Wrinkle severity at periorbital, glabella and forehead lines was evaluated using the 3D fringe projection and 5-point photonumeric VAS. The results of both methods were matched by determining quantitative values for each level of the clinical rating scale. Results High average correlation with age was found for VAS, Wd, maxWd, lWd, Wv, aWa and pWa. With a Wd of 60 to 70μm crow's feet and forehead lines are pronounced first, whereas glabella lines develop in subject's mid-forties, by an Wd of 180μm. Wrinkle severity increases at all locations every 10 years of age by one level of the VAS. This increase corresponds to an increase of Wd about 100 μm at glabella and forehead lines, and about 50 μm at crow's feet. Conclusion The presented reference values for the Validated Assessment Scale are an important step towards an optimized assessment of skin aging and aesthetic dermatological treatments. The data helps to combine the precession of a biophysical measurement with the practical relevance of a clinical rating.

Improved understanding of the anatomy and physiology of the aging face has laid the foundation for adopting an earlier and more comprehensive approach to facial rejuvenation, shifting the focus from individual wrinkle treatment and lift procedures to a holistic paradigm that considers the entire face and its structural framework. This article presents an overview of a comprehensive method to address facial aging. The key components to the reported strategy for improving facial cosmesis include, in addition to augmentation of volume loss, protection with sunscreens and antioxidants; promotion of epidermal cell turnover with techniques such as superficial chemical peels; microlaser peels and microdermabrasion; collagen stimulation and remodeling via light, ultrasound, or radiofrequency (RF)-based methods; and muscle control with botulinum toxin. For the treatment of wrinkles and for the augmentation of pan-facial dermal lipoatrophy, several types of fillers and volumizers including hyaluronic acid (HA), autologous fat, and calcium hydroxylapatite (CaHA) or injectable poly-l-lactic acid (PLLA) are available. A novel bimodal, trivector technique to restore structural facial volume loss that combines supraperiosteal depot injections of volume-depleted fat pads and dermal/subcutaneous injections for panfacial lipoatrophy with PLLA is presented. The combination of treatments with fillers; toxins; light-, sound-, and RF-based technologies; and surgical procedures may help to forestall the facial aging process and provide more natural results than are possible with any of these techniques alone. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

BACKGROUND: Skin and hair appearance is important to body image. Oily skin and oily impaired hair quality which can develop in women taking certain types of hormonal contraceptives may cause psychosocial stress. OBJECTIVES: The aim of the current study was to investigate the effects of an oral monophasic contraceptive (0.03 mg ethinylestradiol/2 mg chlormadinone acetate) for 12 treatment cycles on the pathophysiology of oily skin and oily impaired hair quality in healthy women. METHODS: We assessed changes in hair and skin parameters at baseline 12 24 and 48 weeks in 60 women aged 18-45 years. Psychological well-being was verified by two subject self-assessments (Hair quality Hairdex). RESULTS: Data from 31 subjects showed that treatment significantly improved sebum excretion at capillitium and forehead and the number of terminal hairs. Visual haptic scores revealed significant decreases in capillitium seborrhoea hair condition/density capillitium dandruff and irritation/redness. Subject self-assessment confirmed improvements in hair quality. Treatment was well tolerated. CONCLUSION: Chlormadinone acetate in hormonal contraception provides excellent cosmetic and dermatological benefits which can improve psychosocial well-being. (c) 2012 The Authors. Journal of the European Academy of Dermatology and Venereology (c) 2012 European Academy of Dermatology and Venereology.

Background/purpose The most commonly used method to determine the mechanical ability of skin is the creep test using suction chamber devices. Until now, there is no scientific consensus upon which skin deformation parameters and which body sites are particularly suitable to describe age-related changes in human skin mechanics. The aim of this study was to find those mechanical skin parameters best representing influence of aging at five different body sites. Methods A total of 120 healthy women aged 18-65, divided into four similar age groups, were included in this study. The biomechanical properties of the skin were measured using the Cutometer® MPA 580 on five body sites: cheek, neck, cleavage, volar forearm and back of the hand. In order to analyze parameters referred to 1 mm skin thickness, we also used 20 MHz sonography (DUB 20). Results A high average correlation with age was found for the parameters U(a)/U(f), U(r)/U(e), U(r), U(r)/U(f) and U(a). Only low correlation with age was found for the parameters U(v)/U(e), U(f)-U(a), U(f5)/U(f), U(d)/U(f) and U(a5). The localizations cheek, forearm and neck showed the highest correlation with age, while cleavage showed only low correlation. Conclusion According to the results of our study, we recommend the parameter ratio of elastic recovery to distensibility (U(r)/U(f) ) as well as the gross elasticity (U(a)/U(f)) for evaluation of aging effects on the mechanical properties of skin. Their high correlation with age makes them particularly applicable to represent the influence of aging onto skin mechanical properties. Most suitable localizations to evaluate skin aging are cheek, forearm and neck.

It is generally stated that drinking plenty of water has a positive influence on skin condition. However, there is no published scientific study that has investigated this matter. The aim of our exploratory 'before-after' study was to evaluate the in vivo influence of drinking more than 2 L of mineral water or ordinary tap water per day on skin physiology. Ninety-three healthy subjects were included in our prospective study. After an initial run-in phase of 2 weeks to monitor individual drinking habits, subjects had to drink 2.25 L day(-1) of either mineral water (n = 53) or tap water (n = 40) for 4 weeks. Bioengineering in vivo measurements on the volar forearm included sonographic evaluation of skin thickness and density, determination of skin surface pH, assessment of skin surface morphology, and measurement of finger circumference. Eighty-six subjects completed the study. In the mineral water group measurements revealed a statistically significant decrease in skin density. Skin thickness increased slightly, albeit not at a statistically significant level. However, when separately analysing those individuals from the mineral water group, who had routinely drunken comparably little before the start of the study, their skin thickness increased at a statistically significant level. Skin surface pH remained almost unchanged in the physiologically optimal range. In the tap water group, skin density increased significantly, while skin thickness decreased significantly. Skin surface pH decreased at a statistically significant level. While in the mineral water group finger circumference decreased significantly, measurements in the tap water group revealed a statistically significant increase. Objective skin surface morphology did not change in any group. In summary, drinking more than 2 L of water per day can have a significant impact on skin physiology. The exact effects within the skin seem to differ depending on the nature of the water ingested. Randomized, controlled, double-blind follow-up trials are warranted to confirm the findings of our exploratory pilot study.

Cellulite is a multifactorial condition that is present in 80–90 % of post-pubertal women. Despite its high prevalence, it remains a major cosmetic concern for women. A wide range of products and treatments for cellulite reduction is available; however, no systematic review has been performed so far to evaluate the efficacy of the available treatment options for cellulite. The objective of this review is to provide a systematic evaluation of the scientific evidence of the efficacy of treatments for cellulite reduction. This systematic review followed the PRISMA guidelines for reporting systematic reviews and meta-analyses. Only original articles in English or German reporting data on the efficacy of cellulite treatments from in vivo human studies were considered. In total, 67 articles were analyzed for the following information: therapy, presence of a control group, randomization, blinding, sample size, description of statistical methods, results, and level of evidence. Most of the evaluated studies, including laser- and light-based modalities, radiofrequency, and others had important methodological flaws; some did not use cellulite severity as an endpoint or did not provide sufficient statistical analyses. Of the 67 studies analyzed in this review, only 19 were placebo-controlled studies with randomization. Some evidence for potential benefit was only seen for acoustic wave therapy (AWT) and the 1440 nm Nd:YAG minimally invasive laser. This article provides a systematic evaluation of the scientific evidence of the efficacy of treatment for cellulite reduction. No clear evidence of good efficacy could be identified in any of the evaluated cellulite treatments.

Background Whereas the molecular mechanisms of skin aging are well understood, little information is available concerning the clinical onset and lifetime development of facial wrinkles. Objectives To perform the first systematic evaluation of the lifetime development of facial wrinkles and sex-specific differences using three-dimensional (3D) imaging and clinical rating. Methods 200 men and women aged 20 to 70 were selected. Wrinkle severity of periorbital, glabellar, and forehead lines was evaluated using 3D imaging and validated assessment scales. Results Wrinkle severity was greater at all assessed locations with older age. In men, wrinkles manifested earlier and were more severe than in women. In women, periorbital lines were the first visible wrinkles, in contrast to the forehead lines in men. In both sexes, glabellar lines did not clinically manifest before the age of 40. Conclusion The results of the present study confirm a progressive increase of crow's feet and forehead and glabellar lines in men and women. Although the development of facial wrinkles happens earlier and is more severe in men, perimenopause seems to particularly affect development in women. Clinical ratings and 3D measurements are suitable methods to assess facial wrinkle severity in men and women.

Mid-dermal injection of stabilized hyaluronic acid (HA) is well established as a treatment to reduce the effects of skin aging.To assess the efficacy and safety of a stabilized HA-based gel of non-animal origin manufactured using the patented NASHA® technology (Restylane® Vital Light, Q-Med AB, Uppsala, Sweden) administered using a pre-filled micropuncture injector device for rejuvenation of the skin.Three treatment sessions 4 weeks apart were performed on one side of the face, the dorsum of one of the hands and one side of the décolletage, leaving the other side untreated. Skin quality was assessed via blinded live evaluation and subject satisfaction by questionnaire. Aesthetic change was evaluated independently by the subject and a blinded evaluator. Subjects were followed up to week 36.Thirty subjects aged 40-65 years were enrolled. Overall skin quality across all three treatment areas was judged to be improved on the treated side in over 80% of subjects throughout the study. Significant aesthetic improvements on the treated sides were observed at all visits, with the exception of the décolletage at week 36.This was the first study that used a micropuncture injector device for injection of NASHA gel, and reveals that this is a promising treatment option for rejuvenation of the skin.

The history of beauty is as old as mankind itself--throughout history people have tried to improve their attractiveness and to enhance their beauty. The technical basis for many of nowadays procedures like lipoplasty, breast augmentation or rhinoplasty was thereby initiated more than a hundred years ago and evolved to the modern standards of today. The aim of this article is to recall the early days of aesthetic medicine and show the swift progress up to the highly specialized medical discipline of our modern time. Combining the past, present and future of aesthetic medicine, allows to incorporate this perspective and ultimately to delivery better patient care.

Background Previous studies have shown that the clinical genesis and onset of facial wrinkles as well as the morphology of the extracellular matrix differ between the sexes. The aim of this present clinical study was to do the first systematic assessment of gender-related differences in skin elasticity, with special focus on age-related changes. Material and Methods 300 healthy male and female subjects (20–74 years) were selected following strict criteria including age, sun behavior or smoking habits. Skin mechanical properties were assessed at the cheek, neck, volar forearm and dorsum of the hand using a non-invasive suction device. Results Data analysis shows a significant negative correlation for all parameters and subject's age. At young age results of the relative parameters are higher for women, whereas absolute parameters are higher for men. Parameters referring to the recovery phase change stronger with aging. Discussion The present study verifies the progressive decline of the skin mechanical properties with aging. However, the elastic ability of the skin to recover after stretching is more strongly affected by the aging process than the firmness of the skin. Further, the mechanical properties change differently in men and woman over lifetime.

SynopsisObjectives Evidence is given that differences in skin physiological properties exist between men and women. However, despite an assessable number of available publications, the results are still inconsistent. Therefore, the aim of this clinical study is the first systematic assessment of gender-related differences in skin physiology in men and women, with a special focus on changes over lifetime. Methods A total of 300 healthy male and female subjects (20–74 years) were selected following strict criteria including age, sun behaviour or smoking habits. TEWL, hydration level, sebum production and pH value were measured with worldwide-acknowledged biophysical measuring methods at forehead, cheek, neck, volar forearm and dorsum of hand. Results Until the age of 50 men's TEWL is significantly lower than the water loss of women of the same age, regardless of the location. With ageing gender-related differences in TEWL assimilate. Young men show higher SC hydration in comparison with women. But, whereas SC hydration is stable or even increasing in women over lifetime, the skin hydration in men is progressively decreasing, beginning at the age of 40. Sebum production in male skin is always higher and stays stable with increasing age, whereas sebum production in women progressively decreases over lifetime. Across all localizations and age groups, the pH value in men is below 5, the pH value of female subjects is, aside from limited expectations, higher than 5. Conclusion Skin physiological distinctions between the sexes exist and are particularly remarkable with regard to sebum production and pH value.

Radiofrequency (RF) technology has become a standard treatment in aesthetic medicine with many indications due to its versatility, efficacy, and safety. It is used worldwide for cellulite reduction; acne scar revision; and treatment of hypertrophic scars and keloids, rosacea, and inflammatory acne in all skin types. However, the most common indication for RF technology is the nonablative tightening of tissue to improve skin laxity and reduce wrinkles. Radiofrequency devices are classified as unipolar, bipolar, or multipolar depending on the number of electrodes used. Additional modalities include fractional RF; sublative RF; phase-controlled RF; and combination RF therapies that apply light, massage, or pulsed electromagnetic fields (PEMFs). This article reviews studies and case series on these devices. Radiofrequency technology for aesthetic medicine has seen rapid advancements since it was used for skin tightening in 2003. Future developments will continue to keep RF technology at the forefront of the dermatologist's armamentarium for skin tightening and rejuvenation.

A distinct trend in aesthetic medicine is the patient's demand for efficient, noninvasive treatments with no downtime. Ongoing with this, these so-called lunchtime procedures are expected to be as safe and painless as possible. A new technique based on a combination of radiofrequency (RF) and pulsed electromagnetic fields (PEMF) was recently introduced and is supposed to be effective in the treatment of facial wrinkles and virtually pain free. The objective of this study was to investigate the safety and efficacy of this technology for the treatment of facial rhytides.Thirty-one subjects with facial wrinkles and rhytides were entered into this study. Every subject received 10 treatments of the face with a device that combines 1 MHz radiofrequency with PEMF with a flux of 15 gauss. Patients rated the pain level immediately after the treatment by using a visual analog scale (VAS) for pain. Side effects were recorded at every visit. The study's efficacy end point was evaluated by 2 blinded physicians who rated the standardized pictures from baseline and 3-month follow-up using the Fitzpatrick Wrinkle and Elastosis Scale (FWES).No unexpected adverse side effects were detected or reported for the duration of the study. Both raters recognized improvements of at least 1 grade on the FWES in 30 of 31 subjects (97%). The score decreased from 5.2 before the first treatment to 3.6 at 3 months after the last treatment. Furthermore, all patients rated the treatment to be free of pain on the VAS pain scale.The results of this study show that the combination of multipolar RF with PEMF is a safe, effective, and painless approach to treat facial rhytides and is suitable to answer the demands of patients for safe treatments without pain or downtime.

The protection against water loss and the prevention of substances and bacteria penetrating into the body rank as the most important functions of the skin. This so-called 'skin barrier function' is the natural frontier between the inner organism and the environment, and is primarily formed by the epidermis. An impairment of the skin barrier function is often found in diseased and damaged skin. An influence of ageing on skin barrier function is widely accepted, but has not been conclusively evaluated yet. Therefore, the aim of this clinical study was to assess the potential influence of ageing on skin barrier function, including transepidermal water loss (TEWL), stratum corneum hydration, sebum content and pH value. One hundred and fifty healthy women aged 18-80, divided into five age groups with 30 subjects each, were evaluated in this study. TEWL, hydration level, sebum secretion and pH value of hydro-lipid acid film were measured with worldwide acknowledged biophysical measuring methods at cheek, neck, decollete, volar forearm and dorsum of hand. Whereas TEWL and stratum corneum hydration showed only very low correlation with subject's age, the sebum production decreased significantly with age, resulting in the lowest skin surface lipids levels measured in subjects older than 70 years. The highest skin surface pH was measured in subjects between 50 and 60 years, whereas the eldest age group had the lowest mean pH. The dorsum of the hand was the location with the highest TEWL and lowest stratum corneum hydration in all age groups. The results show that only some parameters related to skin barrier function are influenced by ageing. Whereas sebum production decreases significantly over lifetime and skin surface pH is significantly increased in menopausal woman, TEWL and stratum corneum hydration show only minor variations with ageing.

Carbon black is an industrially produced particulate form of nearly pure elemental carbon. The basic building blocks of carbon black are (1) primary particles, minute pieces of matter with defined physical boundaries; (2) aggregates, collections of strongly bound or fused particles; and (3) agglomerates, collections of weakly bound aggregates. Industrial carbon black is produced within a closed reactor where the primary particles form aggregates, which become the indivisible entities of carbon black. These aggregates then form agglomerates, which are the typical form of carbon black in commerce. Carbon black is often used in in vitro and in vivo particle toxicology investigations as a reference nanoparticle. The toxicology studies often report the sizes of the primary particles but rarely the sizes of the aggregates or agglomerates. It appears in many cases that there is a limited understanding of the fact that carbon black typically does not exist as primary particles but instead exists as aggregates and agglomerates. Moreover, many toxicology studies manipulate carbon black particles in order to disperse them so that the form of carbon black used in these toxicology studies may be substantially different from the form that may be encountered in the workplace environment. Since the main exposure route for carbon black is inhalation, the question arose as to whether inhaled carbon black may deagglomerate or disaggregate to either smaller aggregates or primary particles when in contact with lung fluids. This question relates to the concern that there may be additional hazards of smaller particles, such as their ability to translocate to tissues and organs beyond the lung and the ability to pass through the blood-brain barrier. The purpose of this assessment is to review the existing literature for evidence as to whether carbon black deagglomerates or disaggregates into smaller aggregates or primary particles when in contact with lung fluid. On the basis of a review of the physical characteristics of commercial carbon black and various toxicology studies, it appears that commercially produced carbon black in contact with lung fluid is unlikely to deagglomerate or disaggregate into smaller aggregates or primary particles.

The most commonly used method to determine the mechanical ability of skin is the creep test using suction chamber devices. Until now, there is no scientific consensus upon which skin deformation parameters and which body sites are particularly suitable to describe age-related changes in human skin mechanics. The aim of this study was to find those mechanical skin parameters best representing influence of aging at five different body sites.A total of 120 healthy women aged 18-65, divided into four similar age groups, were included in this study. The biomechanical properties of the skin were measured using the Cutometer® MPA 580 on five body sites: cheek, neck, cleavage, volar forearm and back of the hand. In order to analyze parameters referred to 1 mm skin thickness, we also used 20 MHz sonography (DUB 20).A high average correlation with age was found for the parameters U(a)/U(f), U(r)/U(e), U(r), U(r)/U(f) and U(a). Only low correlation with age was found for the parameters U(v)/U(e), U(f)-U(a), U(f5)/U(f), U(d)/U(f) and U(a5). The localizations cheek, forearm and neck showed the highest correlation with age, while cleavage showed only low correlation.According to the results of our study, we recommend the parameter ratio of elastic recovery to distensibility (U(r)/U(f) ) as well as the gross elasticity (U(a)/U(f)) for evaluation of aging effects on the mechanical properties of skin. Their high correlation with age makes them particularly applicable to represent the influence of aging onto skin mechanical properties. Most suitable localizations to evaluate skin aging are cheek, forearm and neck.