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Saito N, Matsumori K, Kazama T, Sakaguchi S, Okazaki R, Arakawa N, Okamoto S. Skin quality sensor to evaluate vibration and friction generated when sliding over skins. Int J Cosmet Sci 2023; 45:851-861. [PMID: 37565335 DOI: 10.1111/ics.12892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/10/2023] [Accepted: 08/04/2023] [Indexed: 08/12/2023]
Abstract
OBJECTIVE The mechanical condition and tactile evaluation of skin are essential for the development of skin care products. Most of the existing commercial instruments and studies aim to evaluate the skin surface by pressing it for hardness or by using imaging sensors, but there have been few instrumental measurements employing rubbing motion. Here, we have developed a sensor specialized for tactile sensation and the contact phenomenon during skin rubbing. METHODS The developed sensor has three features: It can measure body parts including cheeks and arms, automate the rubbing motion of the probe and measure vibration and friction simultaneously. It is hand-held, with metal probes that rub the skin surface while rotating under a motor drive; it has an accelerometer and a force sensor beneath the probe measuring vibration and friction forces. To evaluate the validity of the sensor's measurements, artificial skin models were measured using the developed sensor and commercially available sensors and the results were compared. The relationship between the sensor output, surface roughness measurement and sensory evaluation was also investigated. Additionally, we evaluated the inter-rater reliability when measuring actual skin. RESULTS The measurements of five artificial skin models with different surface shapes showed a high correlation (r = 0.99) between the vibration intensity values evaluated by the developed sensor and those measured by a tri-axial acceleration sensor attached to a fingernail. The correlation coefficient between the vibration intensity values and surface roughness was r = 0.91, and the correlation with the sensory evaluation score of roughness was r = 0.99. The friction coefficients measured by the developed sensor and the force plate had r = 0.93, based on measurements of five artificial skin models with different friction conditions. The inter-rater correlation coefficients between the three participants of the developed sensor were as high as 0.92 and 0.94 for the vibration and friction measurements respectively. CONCLUSION The vibration intensities and friction coefficients from the sensor were highly correlated with those of the conventional sensor. The inter-rater reliability was also high. The developed sensor can be useful for tactile evaluation in skin-care product development.
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Affiliation(s)
- Naoki Saito
- MIRAI Technology Institute, Shiseido Co., Ltd., Yokohama, Japan
| | - Kohei Matsumori
- MIRAI Technology Institute, Shiseido Co., Ltd., Yokohama, Japan
| | - Taiki Kazama
- MIRAI Technology Institute, Shiseido Co., Ltd., Yokohama, Japan
| | - Saito Sakaguchi
- MIRAI Technology Institute, Shiseido Co., Ltd., Yokohama, Japan
| | - Ryuta Okazaki
- MIRAI Technology Institute, Shiseido Co., Ltd., Yokohama, Japan
| | - Naomi Arakawa
- MIRAI Technology Institute, Shiseido Co., Ltd., Yokohama, Japan
| | - Shogo Okamoto
- Department of Computer Sciences, Tokyo Metropolitan University, Hino, Japan
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Garita-Alvarado CA. Courtship behavior in the knife livebearer Alfaro cultratus (Cyprinodontiformes: Poeciliidae). J Fish Biol 2023; 103:1221-1225. [PMID: 37415430 DOI: 10.1111/jfb.15494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/08/2023]
Abstract
The mating behavior of the knife livebearer Alfaro cultratus is described in detail. During "rubbing," the male swims to a position above the female and gently moves down repeatedly touching the dorsal part of female head with the pelvic fin tips. This courtship behavior constitutes the first report of a pelvic fin male-female contact during mating in poecilids. Based on preliminary evidence, I propose that a sensory bias mechanism could mediate the evolution of signal design/mate choice in this species, which should be tested in further studies.
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Affiliation(s)
- Carlos A Garita-Alvarado
- Museo de Zoología, Escuela de Biología, Universidad de Costa Rica, San José, Costa Rica
- Unidad Multidisciplinaria de Docencia e Investigación, Facultad de Ciencias, Universidad Nacional Autónoma de México, Querétaro, Mexico
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3
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Erdogan G, Yucel S, Bilisik K. Textured Polyester Fiber in Three-Dimensional (3D) Carpet Structure Application: Experimental Characterizations under Compression-Bending-Abrasion- Rubbing Loading. Polymers (Basel) 2023; 15:3006. [PMID: 37514396 PMCID: PMC10383248 DOI: 10.3390/polym15143006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 06/26/2023] [Accepted: 07/03/2023] [Indexed: 07/30/2023] Open
Abstract
In this article, textured polyester fiber was used as pile yarn in three-dimensional woven carpet structures. The properties of developed polyester carpets under various mechanical loading were studied. A statistical method was used to analyze the experimental data. Regression models were proposed to explain the relationships between carpet pile height and density. The study showed that the bending rigidity and curvature of dry and wet polyester pile fiber carpets were influenced by pile height and pile density (indirectly weft density) in that the downward concave large bending curvature was obtained from very dense carpet structures. In addition, the average dry bending rigidity of the carpet was over eight times higher than the average wet bending rigidity of the carpet. The thickness loss (%) and resilience (%) for each recovery period of various polyester carpets were proportional depending on the pile density. It was broadly decreased when the pile density was increased due to the compression load carrying capacity per polyester fiber knot, which was higher in carpets having dense knots compared to sparse knots per area. On the other hand, the polyester pile density and height largely affected the carpet mass losses (%) of all textured polyester carpets under an abrasion load. The number of strokes received after completely fractured polyester pile yarns during a rubbing test were increased when the pile heights for each pile density were increased. Findings from the study can be useful for polyester carpet designers and three-dimensional dry or impregnate polyester fiber-based preform designers in particularly complex shape molding part manufacturing.
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Affiliation(s)
- Gulhan Erdogan
- Department of Textile Engineering, Faculty of Engineering, Erciyes University, Talas, Kayseri 38039, Turkey
| | - Sinem Yucel
- Uniteks Tekstil, Atatürk Organize Sanayi Bölgesi, 10039 sokak, No. 26, Çiğli, İzmir 35620, Turkey
| | - Kadir Bilisik
- Department of Textile Engineering, Faculty of Engineering, Erciyes University, Talas, Kayseri 38039, Turkey
- Nanotechnology Application and Research Centre (ERNAM), Erciyes University, Talas9, Kayseri 3803, Turkey
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Sakpuwadol N, Harnchoowong S, Suchonwanit P. Pretibial Pruritic Papular Dermatitis: A Case Report and Emphasis on Effective Treatment with Pentoxifylline. Clin Cosmet Investig Dermatol 2023; 16:1589-1593. [PMID: 37366429 PMCID: PMC10290853 DOI: 10.2147/ccid.s420726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 06/16/2023] [Indexed: 06/28/2023]
Abstract
Pretibial pruritic papular dermatitis (PPPD) is a distinctive skin disorder in response to persistent pretibial manipulation. Clinically, it manifests as multiple discrete, pruritic, flesh-colored-to-erythematous papules and plaques confined to the pretibial area. The histological hallmark of PPPD comprises irregular epidermal psoriasiform hyperplasia with parakeratosis and spongiosis, dermal fibrosis, and lymphohistiocytic infiltration. Due to its rarity and underrecognition, the prevalence and standard treatment of the disease have yet to be well elucidated. Here, we present a case of PPPD in a 60-year-old female presenting with numerous pruritic, erythematous-to-brownish papules and plaques on bilateral pretibial areas for 1.5 years. The lesions were significantly improved after 1 month of additional treatment with oral pentoxifylline. In this report, we aim to raise awareness in recognizing PPPD since it manifests unique clinical, dermoscopic, and histological features, representing pretibial skin's response to chronic rubbing. In addition, we proposed a novel effective therapy for the disease using pentoxifylline.
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Affiliation(s)
- Nawara Sakpuwadol
- Division of Dermatology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Sarawin Harnchoowong
- Division of Dermatology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Poonkiat Suchonwanit
- Division of Dermatology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
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Su CY, Yeh LK, Tsao YF, Lin WP, Hou CH, Huang HF, Lai CC, Fang HW. The Effect of Different Cleaning Methods on Protein Deposition and Optical Characteristics of Orthokeratology Lenses. Polymers (Basel) 2021; 13:4318. [PMID: 34960869 DOI: 10.3390/polym13244318] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 11/29/2022] Open
Abstract
Orthokeratology lenses are commonly used for myopia control, especially in children. Tear lipids and proteins are immediately adsorbed when the lens is put on the cornea, and protein deposition may cause discomfort or infection. Therefore, we established an in vitro protein deposition analysis by mimicking the current cleaning methods for orthokeratology lens wearers for both short-term and long-term period. The results showed that the amounts of tear proteins accumulated daily and achieved a balance after 14 days when the lens was rubbed to clean or not. Protein deposition also affected the optical characteristics of the lens regardless of cleaning methods. Our results provided an in vitro analysis for protein deposition on the lens, and they may provide a potential effective method for developing care solutions or methods that can more effectively remove tear components from orthokeratology lenses.
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Epure EL, Stoica I, Albu RM, Hulubei C, Barzic AI. New Strategy for Inducing Surface Anisotropy in Polyimide Films for Nematics Orientation in Display Applications. Nanomaterials (Basel) 2021; 11:3107. [PMID: 34835871 DOI: 10.3390/nano11113107] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/10/2021] [Accepted: 11/15/2021] [Indexed: 01/04/2023]
Abstract
The operability of liquid crystal displays is strongly impacted by the orientation aspects of nematics, which in turn are affected by the alignment layer surface features. In this work, two polyimide (PI) structures are obtained based on a cycloaliphatic dianhydride and aromatic or aliphatic diamines with distinct flexibility. The attained PI films have high transmittance (T) for visible radiations, i.e., at 550 nm T > 80%. Here, a novel strategy for creating surface anisotropy in the samples that combines rubbing with a cloth and stretching via pressing is reported. Birefringence and atomic force microscopy (AFM) scans reveal that the generated orientation of the chains is affected by the chemical structure of the polymer and order of the steps involved in the surface treatment. Molecular modeling computations and wettability tests show that the PI structure and produced surface topography are competitive factors, which are impacting the intensity of the interactions with the nematic liquid crystals. The achieved results are of great relevance for designing of reliable display devices with improved uniform orientation of liquid crystals.
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Rogóż M, Haberko J, Wasylczyk P. Light-Driven Linear Inchworm Motor Based on Liquid Crystal Elastomer Actuators Fabricated with Rubbing Overwriting. Materials (Basel) 2021; 14:6688. [PMID: 34772214 DOI: 10.3390/ma14216688] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/27/2021] [Accepted: 11/03/2021] [Indexed: 11/23/2022]
Abstract
Linear displacement is used for positioning and scanning, e.g., in robotics at different scales or in scientific instrumentation. Most linear motors are either powered by rotary drives or are driven directly by pressure, electromagnetic forces or a shape change in a medium, such as piezoelectrics or shape-memory materials. Here, we present a centimeter-scale light-powered linear inchworm motor, driven by two liquid crystal elastomer (LCE) accordion-like actuators. The rubbing overwriting technique was used to fabricate the LCE actuators, made of elastomer film with patterned alignment. In the linear motor, a scanned green laser beam induces a sequence of travelling deformations in a pair of actuators that move a gripper, which couples to a shaft via friction moving it with an average speed in the order of millimeters per second. The prototype linear motor demonstrates how LCE light-driven actuators with a limited stroke can be used to drive more complex mechanisms, where large displacements can be achieved, defined only by the technical constrains (the shaft length in our case), and not by the limited strain of the material. Inchworm motors driven by LCE actuators may be scaled down to sub-millimeter size and can be used in applications where remote control and power supply with light, either delivered in free space beams or via fibers, is an advantage.
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Manyo EY, Picoux B, Reynaud P, Tautou R, Nelias D, Allou F, Petit C. Approach of Pavement Surface Layer Degradation Caused by Tire Contact Using Semi-Analytical Model. Materials (Basel) 2021; 14:2117. [PMID: 33922051 DOI: 10.3390/ma14092117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/11/2021] [Accepted: 04/19/2021] [Indexed: 11/23/2022]
Abstract
New methods of degradations on the pavement’s surface, such as top-down cracking and delamination, caused by the repeated passage of heavy vehicles led to questions about the impact of the contact between the tire and the pavement. In fact, to increase the service life of the structures, future road design methods must have a precise knowledge of the consequences of the contact parameters on the state of stress and deformation in the pavement. In this paper, tractive rolling contact under the effect of friction is modeled by Kalker’s theory using a semi-analytical method (SAM). A tire profile is performed thanks to a digitization by fringes or a photogrammetry technique. The effect of rolling on the main surface extension deformations is then highlighted to study top cracking. At the end of the SAM calculation, contact areas are closed to 200 μdef, exceeding the allowable micro-deformation limit for the initiation of cracking. In addition, results on the main strain directions also give information on the direction of cracking (initiation of longitudinal or transverse cracks). The cracking then becomes evident, leading to a reduced service life.
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9
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Shin MJ, Yoon DK. Role of Stimuli on Liquid Crystalline Defects: From Defect Engineering to Switchable Functional Materials. Materials (Basel) 2020; 13:E5466. [PMID: 33266312 DOI: 10.3390/ma13235466] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 11/27/2020] [Accepted: 11/27/2020] [Indexed: 11/17/2022]
Abstract
Achieving tunable physical properties is currently one of the most exciting research topics. In order to realize this goal, a medium that is responsive to external stimuli and can undergo a change in its physical property is required. Liquid crystal (LC) is a prominent candidate, as its physical and optical properties can be easily manipulated with various stimuli, such as surface anchoring, rubbing, geometric confinement, and external fields. Having broken away from the past devotion to obtaining a uniform domain of LCs, people are now putting significant efforts toward forming and manipulating ordered and oriented defect structures with a unique arrangement within. The complicated molecular order with tunability would benefit the interdisciplinary research fields of optics, physics, photonics, and materials science. In this review, the recent progress toward defect engineering in the nematic and smectic phases by controlling the surface environment and electric field and their combinational methods is introduced. We close the review with a discussion of the possible applications enabled using LC defect structures as switchable materials.
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Elbaklish KH, Saleh SM, Gomaa WA. Lamellar Tarsectomy Procedure In Major Trichiasis Of The Upper Lid. Clin Ophthalmol 2019; 13:2251-2259. [PMID: 31819349 PMCID: PMC6877448 DOI: 10.2147/opth.s210038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 10/15/2019] [Indexed: 11/30/2022] Open
Abstract
Aims Evaluation of failure rate and outcomes between skin and muscle surgery and lamellar tarsectomy procedure in major trichiasis of the upper lid. Design Quasi-randomized clinical study. Methods and subjects One hundred individuals with major trichiasis of the upper lid were enrolled and assigned to either skin and muscle surgery (group A) or a lamellar tarsectomy procedure (group B). Participants were examined at 6 and 12 months. The primary outcome measure (failure rate) was the percentage of participants having five or more eyelashes touching the globe or having surgery performed at any follow-up time in both groups. The secondary outcomes included failure time and changes in both visual acuity and corneal opacity. Results Risk failure over 6 months was 40% in group A and 10% in group B. Absolute risk reduction was 30% (95% CI=14.08–45.92%). Cumulative risk failure over 12 months was 20% in group A and 0.00% in group B after the second intervention. Absolute risk reduction was 20% (95% CI=8.58–31.42%). The number needed to treat (NNT) was 3.3 patients (95% CI=2.2–7.1). The mean number of rubbing lashes was greater in the skin and muscle group than in the lamellar tarsectomy group for 6 and 12 month examinations (0.002, 0.005). The change in visual acuity between the two groups was not significant. Recurrent trichiasis was noticed earlier, 6 weeks after surgery, in the skin and muscle group participants, and later, 3 months after surgery, in the lamellar tarsectomy group participants. Conclusion The lamellar tarsectomy procedure is a good choice for management of major trichiasis of the upper lid. The subjective symptoms and lid margin conjunctivalization were improved in lamellar tarsectomy participants. Absence of new corneal opacity or a change in existing corneal opacification was noticed at the 12 months follow-up study.
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Affiliation(s)
| | - Safaa M Saleh
- Ophthalmology Department, Ain Shams University, Cairo, Egypt
| | - Wael Adel Gomaa
- Ophthalmology Department, Ain Shams University, Cairo, Egypt
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Li Z, Zhang F, Luo X, Guo X, Cai Y, Chang W, Sun J. A New Grinding Force Model for Micro Grinding RB-SiC Ceramic with Grinding Wheel Topography as an Input. Micromachines (Basel) 2018; 9:mi9080368. [PMID: 30424301 PMCID: PMC6187268 DOI: 10.3390/mi9080368] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 07/21/2018] [Accepted: 07/23/2018] [Indexed: 11/16/2022]
Abstract
The ability to predict the grinding force for hard and brittle materials is important to optimize and control the grinding process. However, it is a difficult task to establish a comprehensive grinding force model that takes into account the brittle fracture, grinding conditions, and random distribution of the grinding wheel topography. Therefore, this study developed a new grinding force model for micro-grinding of reaction-bonded silicon carbide (RB-SiC) ceramics. First, the grinding force components and grinding trajectory were analysed based on the critical depth of rubbing, ploughing, and brittle fracture. Afterwards, the corresponding individual grain force were established and the total grinding force was derived through incorporating the single grain force with dynamic cutting grains. Finally, a series of calibration and validation experiments were conducted to obtain the empirical coefficient and verify the accuracy of the model. It was found that ploughing and fracture were the dominate removal modes, which illustrate that the force components decomposed are correct. Furthermore, the values predicted according to the proposed model are consistent with the experimental data, with the average deviation of 6.793% and 8.926% for the normal and tangential force, respectively. This suggests that the proposed model is acceptable and can be used to simulate the grinding force for RB-SiC ceramics in practice.
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Affiliation(s)
- Zhipeng Li
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, China.
- Centre for Precision Manufacturing, Design, Manufacture & Engineering Management, University of Strathclyde, Glasgow G1 1XJ, UK.
| | - Feihu Zhang
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, China.
| | - Xichun Luo
- Centre for Precision Manufacturing, Design, Manufacture & Engineering Management, University of Strathclyde, Glasgow G1 1XJ, UK.
| | - Xiaoguang Guo
- Key Laboratory for Precision and Non-Traditional Machining Technology, Dalian University of Technology, Dalian 116024, China.
| | - Yukui Cai
- Centre for Precision Manufacturing, Design, Manufacture & Engineering Management, University of Strathclyde, Glasgow G1 1XJ, UK.
| | - Wenlong Chang
- Centre for Precision Manufacturing, Design, Manufacture & Engineering Management, University of Strathclyde, Glasgow G1 1XJ, UK.
| | - Jining Sun
- School of Engineering and Physical Science, Heriot Wat University, Edinburgh EH14 4AS, UK.
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Men S, Wong JM, Welch EJ, Xu J, Song S, Deegan AJ, Ravichander A, Casavant B, Berthier E, Wang RK. OCT-based angiography of human dermal microvascular reactions to local stimuli: Implications for increasing capillary blood collection volumes. Lasers Surg Med 2018; 50:908-916. [PMID: 29799134 DOI: 10.1002/lsm.22944] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2018] [Indexed: 12/22/2022]
Abstract
OBJECTIVES To measure and compare microvascular responses within the skin of the upper arm to local stimuli, such as heating or rubbing, through the use of optical coherence tomography angiography (OCTA), and to investigate its impact on blood volume collection. MATERIALS AND METHODS With the use of heat packs or rubbing, local stimulation was applied to the skin of either the left or right upper arm. Data from the stimulated sites were obtained using OCTA comparing pre- and post-stimulation microvascular parameters, such as vessel density, mean vessel diameter, and mean avascular pore size. Additionally, blood was collected using a newly designed collection device and volume was recorded to evaluate the effect of the skin stimulation. RESULTS Nineteen subjects were recruited for local stimulation study (including rubbing and heating) and 21 subjects for blood drawn study. Of these subjects, 14 agreed to participate in both studies. OCTA was successful in monitoring and measuring minute changes in the microvasculature of the stimulated skin. Compared to baseline, significant changes after local heating and rubbing were respectively found in vessel density (16% [P = 0.0004] and 33% [P < 0.0001] increase), mean vessel diameter (14% and 11% increase) and mean avascular pore size (5% [P = 0.0068] and 8% [P = 0.0005] decrease) after stimulations. A gradual recovery was recorded for each parameter, with no difference being measured after 30 minutes. Blood collection volumes significantly increased after stimulations of heating (48% increase; P = 0.049) and rubbing (78% increase; P = 0.048). Significant correlations were found between blood volume and microvascular parameters except mean avascular pore size under the heating condition. CONCLUSIONS OCTA can provide important information regarding microvascular adaptations to local stimuli. With that, both heating and rubbing of the skin have positive effects on blood collection capacity, with rubbing having the most significant effect. Lasers Surg. Med. 50:908-916, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Shaojie Men
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | - Jennifer Manyu Wong
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | - Emily J Welch
- Tasso, Inc., 1631 15th Ave. W., Suite 105, Seattle 98119, Washington
| | - Jingjiang Xu
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | - Anthony J Deegan
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | | | - Benjamin Casavant
- Tasso, Inc., 1631 15th Ave. W., Suite 105, Seattle 98119, Washington
| | - Erwin Berthier
- Tasso, Inc., 1631 15th Ave. W., Suite 105, Seattle 98119, Washington
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
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Abstract
Liquid-liquid transition (LLT) in single-component liquids is one of the most mysterious phenomena in condensed matter. So far, this problem has attracted attention mainly from the fundamental viewpoint. We report the first experimental study on an impact of surface nanostructuring on LLT by using a surface treatment called rubbing, which is the key technology for the production of liquid crystal displays. We find that this rubbing treatment has a significant impact on the kinetics of LLT of an isotropic molecular liquid, triphenyl phosphite. For a liquid confined between rubbed surfaces, surface-induced barrierless formation of the liquid II phase is observed even in a metastable state, where there should be a barrier for nucleation of the liquid II phase in bulk. Thus, surface rubbing of substrates not only changes the ordering behavior but also significantly accelerates the kinetics. This spatiotemporal pattern modulation of LLT can be explained by a wedge-filling transition and the resulting drastic reduction of the nucleation barrier. However, this effect completely disappears in the unstable (spinodal) regime, indicating the absence of the activation barrier even for bulk LLT. This confirms the presence of nucleation-growth- and spinodal decomposition-type LLT, supporting the conclusion that LLT is truly a first-order transition with criticality. Our finding also opens up a new way to control the kinetics of LLT of a liquid confined in a solid cell by structuring its surface on a mesoscopic length scale, which may contribute to making LLT useful for microfluidics and other industrial applications.
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Abstract
CONTEXT At least 15 factors of percutaneous penetration exist that should be considered when investigating dermal absorption profiles of chemicals. Rubbing is one variable that has been understudied, but may play an important role in understanding overall exposure rates, chemical toxicity, dermal absorption and skin's barrier abilities. OBJECTIVE This reviews current data related to the role of massage in enhancing percutaneous penetration and skin decontamination as well as highlights the need for further investigation of its role. RESULTS An in vivo study in rhesus monkeys and guinea pigs measuring amount of drug excreted after being topically applied showed no effect with massage. However, studies measuring permeation rates directly through human and animal skin ex vivo showed rubbing increased flux, reduced skin impedance and increased drug retention in skin. Rubbing also increased effectiveness of reactive skin decontamination lotion (RSDL). CONCLUSION Massage sometimes influences chemical penetration rates and should be studied thoroughly to clarify the mechanisms and factors involved in the possible enhancing effect. This will also reveal more insight regarding the skin's ability to act as a barrier to exogenous substances and its role in risk assessment. How ex vivo results translate to in vivo behaviors still requires further investigation.
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Affiliation(s)
- Christina Phuong
- a Department of Dermatology , University of California-San Francisco (UCSF) , San Francisco , CA , USA
| | - Howard I Maibach
- a Department of Dermatology , University of California-San Francisco (UCSF) , San Francisco , CA , USA
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Vohra V, Arrighetti G, Barba L, Higashimine K, Porzio W, Murata H. Enhanced Vertical Concentration Gradient in Rubbed P3HT:PCBM Graded Bilayer Solar Cells. J Phys Chem Lett 2012; 3:1820-1823. [PMID: 26291866 DOI: 10.1021/jz300710a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Graded bilayer solar cells have proven to be at least as efficient as the bulk heterojunctions when it comes to the Poly(3-hexylthiophene) (P3HT) - [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) donor-acceptor system. However, control of the vertical concentration gradient using simple techniques has never been reported. We demonstrate that rubbing the P3HT layer prior to PCBM deposition induces major morphological changes in the active layer. Using the newly introduced energy-dispersive X-ray spectroscopy element mapping technique, we found that rubbing P3HT induces the formation of an ideal vertical donor-acceptor concentration gradient. Furthermore, the P3HT crystallites undergo a molecular reorientation from edge-on to face-on configuration inducing a better charge transport in the vertical direction. The combination of these two major morphological changes leads to the fabrication of high-performance solar cells that exhibit, to date, the record efficiencies for spin-coated graded bilayers solar cells.
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Affiliation(s)
- Varun Vohra
- †Japan Advanced Institute of Science and Technology (JAIST), School of Materials Science, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
| | - Gianmichele Arrighetti
- ‡Istituto di Cristallografia del CNR - c/o Sincrotrone Elettra, Strada Statale 14-Km 163,5 Area Science Park, 34012 Basovizza, Trieste, Italy
| | - Luisa Barba
- ‡Istituto di Cristallografia del CNR - c/o Sincrotrone Elettra, Strada Statale 14-Km 163,5 Area Science Park, 34012 Basovizza, Trieste, Italy
| | - Koichi Higashimine
- †Japan Advanced Institute of Science and Technology (JAIST), School of Materials Science, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
| | - William Porzio
- §Istituto per lo Studio delle Macromolecole (ISMAC) Via Bassini, 15, Milano, 20133, Italy
| | - Hideyuki Murata
- †Japan Advanced Institute of Science and Technology (JAIST), School of Materials Science, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
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