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The Neglected Importance of Sleep on the Formation and Aggravation of Facial Wrinkles and Their Prevention  [PDF]
Borut Poljsak, Aleksandar Godic, Andrej Starc, Raja Dahmane
Journal of Cosmetics, Dermatological Sciences and Applications (JCDSA) , 2016, DOI: 10.4236/jcdsa.2016.63012
Abstract: The duration of sleep and the position of the face while resting on a pillow have a negative impact on the facial skin appearance and may lead to the formation of sleep wrinkles. Sleep lines occur when there is repetitive, long-term tension on the facial skin, which pushes or pulls the skin in a direction that is perpendicular to the direction of the muscles of the face. These lines tend to be more vertically oriented than expression lines and can be found on the forehead, around the eyebrows, the eyes, the cheeks, the chin, and the nasolabial folds. Our studies revealed that the average reduction of wrinkles in total investigated area of the face (expressed as the density of wrinkle per surface skin) was approximately 12% after 28 days of sleep on a specially-designed pillow. The specially designed anti-wrinkle pillows eliminate the pressure on the cheeks, the eyes and the mouth during sleep. Many such pillows have been designed to reduce the aging process and to encourage users to sleep in specific positions. Evidence supporting the claim that a special pillow prevents wrinkles was presented. Nevertheless, prolonged human studies are required to further elucidate the role of sleeping on appearance of facial wrinkles.
Estimating the Position, Number and Length of Forehead Wrinkles Using Neural Network  [cached]
Ayman AbuBaker,Ali Mehdi
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: A novel approach towards 2D Facial Aging (FA) techniques using Neural Network (NN) is proposed in this study. This approach is proposed to automatically predicate the position, number and length of wrinkles on the forehead area. The method is divided into three main stages; the first stage is the preprocessing stage, where the forehead area is manually cropped then filtered to gain sharpness. After that, the wrinkles segmentation process is carried out using row-by-row threshold, morphological erosion and connected component labeling to accurately extract the wrinkles form the image. Finally, the NN is used to convert the detected wrinkle lengths from 2D to 3D curvature shape. The proposed method is objectively compared with other techniques and can accurately predict the position, number and length of the forehead wrinkles in different ages.
Formation and control of wrinkles in graphene by the wedging transfer method  [PDF]
V. E. Calado,G. F. Schneider,A. M. M. G. Theulings,C. Dekker,L. M. K. Vandersypen
Physics , 2012, DOI: 10.1063/1.4751982
Abstract: We study the formation of wrinkles in graphene upon wet transfer onto a target substrate, whereby draining of water appears to play an important role. We are able to control the orientation of the wrinkles by tuning the surface morphology. Wrinkles are absent in flakes transferred to strongly hydrophobic substrates, a further indication of the role of the interaction of water with the substrate in wrinkle formation. The electrical and structural integrity of the graphene is not affected by the wrinkles, as inferred from Raman measurements and electrical conductivity measurements.
REVIEW OF METHODS OF WRINKLE STUDIES BASED ON TENSION FIELD THEORY
基于张力场理论的薄膜褶皱研究评述

LI Yunliang,TIAN Zhenhui,TAN Huifeng,
李云良
,田振辉,谭惠丰

力学与实践 , 2008,
Abstract: Tension field theory has been used to study membrane wrinkle for a long time. This theory ignores membrane's bending rigidity, and assumes that wrinkling region is in an uniaxial stress condition. Wrinkles are oriented in the direction of the local major principal stress, and the minor principal stress, in the direction perpendicular to the wrinkle direction, is zero. Many wrinkle models are based on this method. They modify the constitutive relation or deformation gradient, then through numerical method, obtain the stress distribution and the direction of wrinkle. The main disadvantage is that it can not obtain some information of wrinkles such as wavelength, amplitude and number. Wrinkle analysis based on energy method first assumes the deforming pattern, and then obtain the expression of wrinkle's amplitude and wavelength through energy relations. This paper compares different models of membrane wrinkle, and discusses development trends of membrane wrinkle research.
Structure and electronic transport in graphene wrinkles  [PDF]
Wenjuan Zhu,Tony Low,Vasili Perebeinos,Ageeth A. Bol,Yu Zhu,Hugen Yan,Jerry Tersoff,Phaedon Avouris
Physics , 2012, DOI: 10.1021/nl300563h
Abstract: Wrinkling is a ubiquitous phenomenon in two-dimensional membranes. In particular, in the large-scale growth of graphene on metallic substrates, high densities of wrinkles are commonly observed. Despite their prevalence and potential impact on large-scale graphene electronics, relatively little is known about their structural morphology and electronic properties. Surveying the graphene landscape using atomic force microscopy, we found that wrinkles reach a certain maximum height before folding over. Calculations of the energetics explain the morphological transition, and indicate that the tall ripples are collapsed into narrow standing wrinkles by van der Waals forces, analogous to large-diameter nanotubes. Quantum transport calculations show that conductance through these collapsed wrinkle structures is limited mainly by a density-of-states bottleneck and by interlayer tunneling across the collapsed bilayer region. Also through systematic measurements across large numbers of devices with wide folded wrinkles, we find a distinct anisotropy in their electrical resistivity, consistent with our transport simulations. These results highlight the coupling between morphology and electronic properties, which has important practical implications for large-scale high-speed graphene electronics.
Dynamics of wrinkles on a vesicle in external flow  [PDF]
K. S. Turitsyn,S. S. Vergeles
Physics , 2007, DOI: 10.1103/PhysRevLett.100.028103
Abstract: Recent experiments by Kantsler et. al. (2007) have shown that the relaxational dynamics of a vesicle in external elongation flow is accompanied by the formation of wrinkles on a membrane. Motivated by these experiments we present a theory describing the dynamics of a wrinkled membrane. Formation of wrinkles is related to the dynamical instability induced by negative surface tension of the membrane. For quasi-spherical vesicles we perform analytical study of the wrinkle structure dynamics. We derive the expression for the instability threshold and identify three stages of the dynamics. The scaling laws for the temporal evolution of wrinkling wavelength and surface tension are established and confirmed numerically.
PREDICTION OF WRINKLE DEFORMATIONS IN THE SPACE MEMBRANE STRUCTURES
空间薄膜结构的褶皱形变预测

WANG Changguo,DU Xingwen,WAN Zhimin,
王长国
,杜星文,万志敏

力学与实践 , 2006,
Abstract: The space inflatable structure is a new construction technology and is the main demanding object in the future space activities. The inflatable structure is mainly made up of membrane; therefore, the maintenance of the structural surface accuracy is one of the most important problems. Wrinkling is the unique characteristic of the flexible membranes, and the wrinkles degrade the surface accuracy and the structural performance, so, the study on wrinkles in membrane structures is desirable and essential. In this paper, a prediction model of wrinkles is proposed, based on the buckling theory, and the wrinkles, including the wrinkle amplitude, wrinkle wavelength and the critical compressive stress, in a rectangular membrane subjected to in-plane horizontal shearing loads are predicted using the method proposed in the present paper. The predicted results show good agreement with our recent experiments and the reported data.
Evaluation of Safety and Efficacy of the MaximusTM System for Facial Wrinkles  [PDF]
Nikolay Potekaev,Olga Zhukova
Journal of Cosmetics, Dermatological Sciences and Applications (JCDSA) , 2013, DOI: 10.4236/jcdsa.2013.32024
Abstract: Introduction: There is a growing demand for non-invasive methods with no down time and minimal risk for facial skin rejuvenation and treatment of wrinkles. The Maximus system, based on TriLipo technology, combines radiofrequency and Dynamic Muscle Activation (DMA). We evaluated the safety and efficacy of the MaximusTM system for the treatment of facial wrinkles. Methods: Twenty women received 8 weekly treatments for facial wrinkles using the Maximus system. Treatment efficacy was assessed by comparing pre- and post-treatment photographs, assessing skin characteristics using the 3D Visioscan system, assessing skin microtopography using the DUB ultrasonic scanning system, assessing microcirculation conditions of facial skin using Laser Doppler Flowmetry (LDF) and subjective evaluation of skin improvement. Results: No adverse events were observed. Following the treatments, positive changes in skin flakiness (scaliness), roughness, smoothness and wrinkles were demonstrated using Visioscan. A thickening of the epidermal-dermal layer and increased structural homogeneity were observed by ultrasound, hyperechogenicity was increased and areas of hypoechogenicity reduced. Microcirculation was improved, corresponding with a positive trend for improved skin characteristics. Conclusions: The Maximus system powered by the TriLipo technology is a non-invasive, effective, safe, and virtually painless treatment for reduction of wrinkles and facial skin rejuvenation.
Pillow use: the behavior of cervical stiffness, headache and scapular/arm pain  [cached]
Susan J Gordon,Karen A Grimmer-Somers,Patricia H Trott
Journal of Pain Research , 2010,
Abstract: Susan J Gordon1,2, Karen A Grimmer-Somers3, Patricia H Trott41Associate Professor, School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Townsville, Australia; 2Member, International Centre for Allied Health Evidence, University of South Australia, Australia; 3Professor of Allied Health, School of Health Sciences, University of South Australia, Director, International Centre for Allied Health Evidence, University of South Australia, Australia; 4Associate Professor, School of Health Sciences, University of South AustraliaBackground: Pillows are intended to support the head and neck in a neutral position to minimize biomechanical stresses on cervical structures whilst sleeping. Biomechanical stresses are associated with waking cervical symptoms. This paper adds to the scant body of research investigating whether different pillow types produce different types and frequencies of waking symptoms in asymptomatic subjects.Methods: A random-allocation block-design blinded field trial was conducted in a large South Australian regional town. Subjects were side-sleepers using one pillow only, and not receiving treatment for cervicothoracic problems. Waking cervical stiffness, headache and scapular/arm pain were recorded daily. Five experimental pillows (polyester, foam regular, foam contour, feather, and latex) were each trialed for a week. Subjects’ ‘own’ pillow was the control (a baseline week, and a washout week between each experimental pillow trial week). Subjects reported waking symptoms related to known factors (other than the pillow), and subjects could ‘drop out’ of any trial pillow week.Results: Disturbed sleep unrelated to the pillow was common. Waking symptoms occurring at least once in the baseline week were reported by approximately 20% of the subjects on their ‘own’ pillow. The feather trial pillow performed least well, producing the highest frequency of waking symptoms, while the latex pillow performed best. The greatest number of ‘drop outs’ occurred on the feather pillow. The foam contour pillow performed no better than the foam regular pillow.Conclusion: ‘Own’ pillows did not guarantee symptom-free waking, and thus were a questionable control. The trial pillows had different waking symptom profiles. Latex pillows can be recommended over any other type for control of waking headache and scapular/arm pain.Keywords: pillow type, cervical stiffness, arm pain, headache
Experimental Study of the Wrinkle of Space Planar Film Reflect-jarray
空间薄膜阵面结构褶皱的实验研究

XIAO Wei-wei,CHEN Wu-jun,FU Gong-yi,
肖薇薇
,陈务军,付功义

实验力学 , 2011,
Abstract: The presence of wrinkle in film array may significantly influence the performance of aerospace craft. Wrinkling control is thus difficulty to develop membrane aerospace structure. White-jlight scanning technology was used to test the wrinkle characteristics of a square planar film reflect-jarray subjected to the action of a pure shear force. Test results show that as shear force increases, the wrinkle quantity in the membrane increases, the amplitude of the wrinkles also increases, and the flatness of the membrane surface decreases. With the pre-jstress in the membrane increasing, the wrinkle quantity increases, but the wrinkle amplitude drops. The flatness of the membrane surface increases a little. Results also show that the existence of glue seam on membrane, the direction of seam with respect to the shear make the wrinkling more complex. Above results are valuable in the design of space planar film reflect-jarray structure.
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