Displaying publications 1 - 20 of 23 in total

  1. Wan Abas WA
    Biomed Mater Eng, 1995;5(2):59-63.
    PMID: 7655319
    The response of human skin to "stress relaxation" tests at low loads in vitro was investigated. A number of behaviours, other than those already well established and documented, were observed. The significant behaviours are pure recovery and relaxation-recovery. Other behaviours observed are temporary stress recovery during the relaxation process, and momentary sudden non-linear drop in stress value followed by a second relaxation. The pure recovery and relaxation-recovery responses are repeatable. The latter represents the transitional response between the well-known behaviour of stress relaxation and the behaviour of stress recovery.
    Matched MeSH terms: Skin Physiological Phenomena*
  2. Wan Abas WA
    Biomed Mater Eng, 1994;4(7):473-86.
    PMID: 7881331
    The response of human skin to biaxial stretch tests in vivo was investigated and compared to the response to uniaxial tension. The results obtained illustrate the nonlinear, anisotropic, and viscoelastic (time-dependent) properties of skin under biaxial stretch. Preconditioning in the load-extension response was found not to be prominent. The results also suggest that the response of skin to a biaxial stretch in vivo is qualitatively similar to that in vitro. Values of the terminal stiffness and limit strain of skin under a biaxial stretch are found.
    Matched MeSH terms: Skin Physiological Phenomena*
  3. Wan Abas WA, Asseli MR
    Biomed Mater Eng, 1994;4(7):463-71.
    PMID: 7881330
    Local strains acting across an area of skin loaded uniaxially in vivo are converted to stresses using the standard elastic formulae. The stress values are compared to those obtained using the classical Bossinesq and Michell stress functions. The results indicate that these functions are capable of describing the response of the skin, both in the low load and the high load regions.
    Matched MeSH terms: Skin Physiological Phenomena*
  4. Omam S, Babini MH, Sim S, Tee R, Nathan V, Namazi H
    Comput Methods Programs Biomed, 2020 Feb;184:105293.
    PMID: 31887618 DOI: 10.1016/j.cmpb.2019.105293
    BACKGROUND AND OBJECTIVE: Human body is covered with skin in different parts. In fact, skin reacts to different changes around human. For instance, when the surrounding temperature changes, human skin will react differently. It is known that the activity of skin is regulated by human brain. In this research, for the first time we investigate the relation between the activities of human skin and brain by mathematical analysis of Galvanic Skin Response (GSR) and Electroencephalography (EEG) signals.

    METHOD: For this purpose, we employ fractal theory and analyze the variations of fractal dimension of GSR and EEG signals when subjects are exposed to different olfactory stimuli in the form of pleasant odors.

    RESULTS: Based on the obtained results, the complexity of GSR signal changes with the complexity of EEG signal in case of different stimuli, where by increasing the molecular complexity of olfactory stimuli, the complexity of EEG and GSR signals increases. The results of statistical analysis showed the significant effect of stimulation on variations of complexity of GSR signal. In addition, based on effect size analysis, fourth odor with greatest molecular complexity had the greatest effect on variations of complexity of EEG and GSR signals.

    CONCLUSION: Therefore, it can be said that human skin reaction changes with the variations in the activity of human brain. The result of analysis in this research can be further used to make a model between the activities of human skin and brain that will enable us to predict skin reaction to different stimuli.

    Matched MeSH terms: Skin Physiological Phenomena*
  5. Yasin ZAM, Ibrahim F, Rashid NN, Razif MFM, Yusof R
    Curr Pharm Biotechnol, 2017;18(11):864-876.
    PMID: 29256348 DOI: 10.2174/1389201019666171219105920
    BACKGROUND: Skin is the largest and most visible organ of the body. Many of its functions include temperature regulation, immunity from microorganisms, maintaining electrolyte balance, and protection from physical injuries, chemical agents and ultraviolet (UV) radiation. Aging occurs in every layer of the skin, primarily due to the degradation of its components. Induction of degradative enzymes and the abundant production of reactive oxygen species lead to skin aging. Understanding the complexity of skin structure and factors contributing to the skin aging will help us impede the aging process. Applications of anti-aging products are a common method to prevent or repair damages that lead to aging.

    CONCLUSION: This review will provide information on the causes and indicators of skin aging as well as examine studies that have used plants to produce anti-aging products.

    Matched MeSH terms: Skin Physiological Phenomena/drug effects
  6. Ali F, Khan I, Shafie S
    PLoS One, 2014;9(2):e85099.
    PMID: 24551033 DOI: 10.1371/journal.pone.0085099
    Closed form solutions for unsteady free convection flows of a second grade fluid near an isothermal vertical plate oscillating in its plane using the Laplace transform technique are established. Expressions for velocity and temperature are obtained and displayed graphically for different values of Prandtl number Pr, thermal Grashof number Gr, viscoelastic parameter α, phase angle ωτ and time τ. Numerical values of skin friction τ 0 and Nusselt number Nu are shown in tables. Some well-known solutions in literature are reduced as the limiting cases of the present solutions.
    Matched MeSH terms: Skin Physiological Phenomena
  7. Goh CF, Mohamed Faisal N, Ismail FN
    Skin Pharmacol Physiol, 2021;34(6):351-362.
    PMID: 33853085 DOI: 10.1159/000514995
    INTRODUCTION: At present, there is a lack of baseline data on the facial skin biophysical profile of women in Malaysia. The implications related to the daily habits and facial skincare product use on the skin biophysical condition are, thus, unknown. In this study, we aim to evaluate facial skin biophysical parameters of Malaysian women and examine the influence of demographic characteristics, daily habits, and facial skincare product use on these parameters.

    METHODS: Four skin biophysical parameters - transepidermal water loss (TEWL), melanin content, elasticity, and collagen intensity - were assessed on the cheek of the subjects (20-60 years). Demographic background, daily habits, and skincare product use were gauged through a survey. Only 197 from the 213 subjects recruited initially were used for analysis after the data were screened for normality.

    RESULTS: The biophysical parameters were similar in different races, except a higher melanin content in Indian female individuals. Elasticity and collagen intensity reduced with age, while melanin content increased in the older age-groups. But no difference was observed in TEWL at different ages. Evaluating the influence of daily habits, we observed that exercise significantly lowered TEWL and increased melanin content, which may be associated with UV radiation exposure. Facial skincare products are popular among the female subjects (>85% users). Products with moisturizing, sunscreening, and other skincare functions (astringent, antiaging, and anti-wrinkle) were preferred by subjects of all ages. These product functions significantly improve skin elasticity and reduce melanin content in the young adults. While aged women recognized the importance of having an additional skin-lightening function in their skincare routine. Although the influence of individual skincare function on skin biophysical parameters was mostly positive, the alteration of these parameters varied at different ages.

    CONCLUSION: This is the first report of facial skin biophysical profile of Malaysian women. There is no difference among 3 major races saved for melanin content. This work demonstrated age-dependent influences on the biophysical parameters, except TEWL. The significance of skincare product use is well reflected in the improvement of these parameters at different age-groups based on individual skincare functions.

    Matched MeSH terms: Skin Physiological Phenomena
  8. Mutashar S, Hannan MA, Samad SA, Hussain A
    Sensors (Basel), 2014;14(7):11522-41.
    PMID: 24984057 DOI: 10.3390/s140711522
    The use of wireless communication using inductive links to transfer data and power to implantable microsystems to stimulate and monitor nerves and muscles is increasing. This paper deals with the development of the theoretical analysis and optimization of an inductive link based on coupling and on spiral circular coil geometry. The coil dimensions offer 22 mm of mutual distance in air. However, at 6 mm of distance, the coils offer a power transmission efficiency of 80% in the optimum case and 73% in the worst case via low input impedance, whereas, transmission efficiency is 45% and 32%, respectively, via high input impedance. The simulations were performed in air and with two types of simulated human biological tissues such as dry and wet-skin using a depth of 6 mm. The performance results expound that the combined magnitude of the electric field components surrounding the external coil is approximately 98% of that in air, and for an internal coil, it is approximately 50%, respectively. It can be seen that the gain surrounding coils is almost constant and confirms the omnidirectional pattern associated with such loop antennas which reduces the effect of non-alignment between the two coils. The results also show that the specific absorption rate (SAR) and power loss within the tissue are lower than that of the standard level. Thus, the tissue will not be damaged anymore.
    Matched MeSH terms: Skin Physiological Phenomena*
  9. Ying CK, Kandaiya S
    J Radiol Prot, 2010 Sep;30(3):585-96.
    PMID: 20826892 DOI: 10.1088/0952-4746/30/3/012
    Interventional cardiology (IC) procedures are known to give high radiation doses to patients and cardiologists as they involve long fluoroscopy times and several cine runs. Patients' dose measurements were carried out at the cardiology department in a local hospital in Penang, Malaysia, using Gafchromic XR-RV2 films. The dosimetric properties of the Gafchromic film were first characterised. The film was energy and dose rate independent but dose dependent for the clinically used values. The film had reproducibility within ± 3% when irradiated on three different days and hence the same XR-RV2 dose-response calibration curve can be used to obtain patient entrance skin dose on different days. The increase in the response of the film post-irradiation was less than 4% over a period of 35 days. For patient dose measurements, the films were placed on the table underneath the patient for an under-couch tube position. This study included a total of 44 patients. Values of 35-2442 mGy for peak skin dose (PSD) and 10.9-344.4 Gy cm(2) for dose-area product (DAP) were obtained. DAP was found to be a poor indicator of PSD for PTCA procedures but there was a better correlation (R(2) = 0.7344) for CA + PTCA procedures. The highest PSD value in this study exceeded the threshold dose value of 2 Gy for early transient skin injury recommended by the Food and Drug Administration.
    Matched MeSH terms: Skin Physiological Phenomena*
  10. Zainuddin A, Makpol S, Chua KH, Abdul Rahim N, Yusof YA, Ngah WZ
    Med J Malaysia, 2008 Jul;63 Suppl A:73-4.
    PMID: 19024990
    Validation of housekeeping gene is important for accurate quantitation of RNA in real time RT-PCR technique. The purpose of this study was to determine the validity of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as a housekeeping gene for quantitative real time RT-PCR assessment in human skin fibroblast senescent model. The cells were divided into different treatment groups; young (passage 4), senescent (passage 30), treatment with H2O2 and treatment with A-tocotrienol prior to H2O2 treatment. Our results showed that the expression level of GAPDH was constant with different treatment groups. Therefore, we concluded that GAPDH was suitable to be used as housekeeping gene in human skin fibroblast senescent model.
    Matched MeSH terms: Skin Physiological Phenomena*
  11. Manssor NA, Radzi Z, Yahya NA, Mohamad Yusof L, Hariri F, Khairuddin NH, et al.
    Skin Pharmacol Physiol, 2016;29(2):55-62.
    PMID: 26836267 DOI: 10.1159/000431328
    Mechanical properties of expanded skin tissue are different from normal skin, which is dependent mainly on the structural and functional integrity of dermal collagen fibrils. In the present study, mechanical properties and surface topography of both expanded and nonexpanded skin collagen fibrils were evaluated. Anisotropic controlled rate self-inflating tissue expanders were placed beneath the skin of sheep's forelimbs. The tissue expanders gradually increased in height and reached equilibrium in 2 weeks. They were left in situ for another 2 weeks before explantation. Expanded and normal skin samples were surgically harvested from the sheep (n = 5). Young's modulus and surface topography of collagen fibrils were measured using an atomic force microscope. A surface topographic scan showed organized hierarchical structural levels: collagen molecules, fibrils and fibers. No significant difference was detected for the D-banding pattern: 63.5 ± 2.6 nm (normal skin) and 63.7 ± 2.7 nm (expanded skin). Fibrils from expanded tissues consisted of loosely packed collagen fibrils and the width of the fibrils was significantly narrower compared to those from normal skin: 153.9 ± 25.3 and 106.7 ± 28.5 nm, respectively. Young's modulus of the collagen fibrils in the expanded and normal skin was not statistically significant: 46.5 ± 19.4 and 35.2 ± 27.0 MPa, respectively. In conclusion, the anisotropic controlled rate self-inflating tissue expander produced a loosely packed collagen network and the fibrils exhibited similar D-banding characteristics as the control group in a sheep model. However, the fibrils from the expanded skin were significantly narrower. The stiffness of the fibrils from the expanded skin was higher but it was not statistically different.
    Matched MeSH terms: Skin Physiological Phenomena*
  12. Jong WL, Wong JH, Ung NM, Ng KH, Ho GF, Cutajar DL, et al.
    J Appl Clin Med Phys, 2014 Sep 08;15(5):4869.
    PMID: 25207573 DOI: 10.1120/jacmp.v15i5.4869
    In vivo dosimetry is important during radiotherapy to ensure the accuracy of the dose delivered to the treatment volume. A dosimeter should be characterized based on its application before it is used for in vivo dosimetry. In this study, we characterize a new MOSFET-based detector, the MOSkin detector, on surface for in vivo skin dosimetry. The advantages of the MOSkin detector are its water equivalent depth of measurement of 0.07 mm, small physical size with submicron dosimetric volume, and the ability to provide real-time readout. A MOSkin detector was calibrated and the reproducibility, linearity, and response over a large dose range to different threshold voltages were determined. Surface dose on solid water phantom was measured using MOSkin detector and compared with Markus ionization chamber and GAFCHROMIC EBT2 film measurements. Dependence in the response of the MOSkin detector on the surface of solid water phantom was also tested for different (i) source to surface distances (SSDs); (ii) field sizes; (iii) surface dose; (iv) radiation incident angles; and (v) wedges. The MOSkin detector showed excellent reproducibility and linearity for dose range of 50 cGy to 300 cGy. The MOSkin detector showed reliable response to different SSDs, field sizes, surface, radiation incident angles, and wedges. The MOSkin detector is suitable for in vivo skin dosimetry.
    Matched MeSH terms: Skin Physiological Phenomena*
  13. Nour S, Imani R, Chaudhry GR, Sharifi AM
    J Biomed Mater Res A, 2021 04;109(4):453-478.
    PMID: 32985051 DOI: 10.1002/jbm.a.37105
    Skin injuries and in particular, chronic wounds, are one of the major prevalent medical problems, worldwide. Due to the pivotal role of angiogenesis in tissue regeneration, impaired angiogenesis can cause several complications during the wound healing process and skin regeneration. Therefore, induction or promotion of angiogenesis can be considered as a promising approach to accelerate wound healing. This article presents a comprehensive overview of current and emerging angiogenesis induction methods applied in several studies for skin regeneration, which are classified into the cell, growth factor, scaffold, and biological/chemical compound-based strategies. In addition, the advantages and disadvantages of these angiogenic strategies along with related research examples are discussed in order to demonstrate their potential in the treatment of wounds.
    Matched MeSH terms: Skin Physiological Phenomena/drug effects
  14. Tan HT, Ellis JA, Koplin JJ, Martino D, Dang TD, Suaini N, et al.
    Pediatr Allergy Immunol, 2014 Oct;25(6):608-10.
    PMID: 24912553 DOI: 10.1111/pai.12245
    Matched MeSH terms: Skin Physiological Phenomena*
  15. Abdul Rahim N, Makpol S, Chua KH, Yusof YA, Top GM, Ngah WZ
    Med J Malaysia, 2008 Jul;63 Suppl A:71-2.
    PMID: 19024989
    Stress-induced premature senescence (SIPS) model is in vitro model of cellular aging. In this study, apoptosis was evaluated in SIPS model and in replicative senescent fibroblasts. We also compared the activity of senescence-associated beta-galactosidase (SA-beta gal) as a biomarker of cellular aging. Our results suggested that SIPS model and senescent fibroblasts might share similar mechanism of aging and apoptosis pathway.
    Matched MeSH terms: Skin Physiological Phenomena/drug effects*
  16. Ebisawa K, Kato R, Okada M, Kamei Y, Mazlyzam AL, Narita Y, et al.
    Med J Malaysia, 2008 Jul;63 Suppl A:41.
    PMID: 19024974
    Two types of cell therapy for facial anti-aging in my clinical experience are introduced in this presentation. One therapy is cultured gingival fibroblasts injection. This procedure lasts for at least one year, making it a good option for patients. The other is platelet rich plasma injection. The results of the preliminary data are promising, but not yet well understood. More clinical data and long-term follow-up is needed.
    Matched MeSH terms: Skin Physiological Phenomena*
  17. Fatimah SS, Chua K, Tan GC, Azmi TI, Tan AE, Abdul Rahman H
    Cytotherapy, 2013 Aug;15(8):1030-41.
    PMID: 23830235 DOI: 10.1016/j.jcyt.2013.05.003
    The aim of the present study was to evaluate the effects of air-liquid interface on the differentiation potential of human amnion epithelial cells (HAECs) to skin-like substitute in organotypic culture.
    Matched MeSH terms: Skin Physiological Phenomena*
  18. Lai CCK, Md Nor N, Kamaruddin NA, Jamil A, Safian N
    Clin Exp Dermatol, 2021 Jan;46(1):58-64.
    PMID: 32619023 DOI: 10.1111/ced.14363
    BACKGROUND: Pruritus is common in patients with diabetes mellitus (DM), and may lead to complex dermatological conditions if left untreated. Pruritus can be caused by increased transepidermal water loss (TEWL) and reduced skin hydration.

    AIMS: To compare TEWL and skin hydration in patients with DM and controls, and to investigate associations between TEWL and skin hydration with glycated haemoglobin (HbA1c), fasting blood sugar (FBS), treatment, peripheral neuropathy (PN) and age in patients with diabetes.

    METHODS: This was a prospective, case-control study carried out at a tertiary medical centre in Kuala Lumpur, Malaysia. TEWL and skin hydration measurements were taken at six different body sites in both groups.

    RESULTS: In total, 146 patients (73 cases, 73 controls) were included (24 men and 49 women in each group). No significant difference in TEWL or skin hydration was seen between patients with DM and controls, but there were significant reductions in skin hydration in patients with DM who had FBS > 7 mmol/L (P  6.5% (P  1 U/kg/day (P  45 years old, there was a significant reduction in TEWL (P = 0.04) and hydration (P skin hydration in patients with DM compared with controls. In the DM group, reduction in skin hydration was associated with uncontrolled FBS and PN but not with HbA1c or DM treatment, whereas TEWL was lower in patients with FBS > 8 mmol/L and increased in patients with higher insulin requirement.

    Matched MeSH terms: Skin Physiological Phenomena*
  19. Kuze N, Malim TP, Kohshima S
    Am J Primatol, 2005 Apr;65(4):353-76.
    PMID: 15834889
    Orangutans display remarkable developmental changes and sexual differences in facial morphology, such as the flanges or cheek-pads that develop only on the face of dominant adult males. These changes suggest that facial morphology is an important factor in visual communication. However, developmental changes in facial morphology have not been examined in detail. We studied developmental changes in the facial morphology of the Borneo orangutan (Pongo pygmaeus) by observing 79 individuals of various ages living in the Sepilok Orangutan Rehabilitation Centre (SORC) in Malaysia and in Japanese zoos. We also analyzed photographs of one captive male that were taken over a period of more than 16 years. There were clear morphological changes that occurred with growth, and we identified previously unreported sexual and developmental differences in facial morphology. Light-colored skin around the eyes and mouth is most prominent in animals younger than 3 years, and rapidly decreases in area through the age of approximately 7 years. At the same time, the scattered, erect hairs on the head (infant hair) become thick, dense hairs lying on the head (adult hair) in both sexes. The results suggest that these features are infant signals, and that adult signals may include darkened face color, adult hair, whiskers, and a beard, which begin to develop after the age of approximately 7 years in both sexes. In females, the eyelids remain white even after 10 years, and turn black at around the age of 20; in males, the eyelids turn black before the age of 10. The whiskers and beards of adults are thicker in males than in females, and are fully developed before the age of 10 in males, while they begin to develop in females only after approximately 20 years. White eyelids and undeveloped whiskers and beards may be visual signals that are indicative of young adult females. Our results also show that the facial morphology of the unflanged male is similar to that of the adult female, although it has also been pointed out that unflanged males resemble younger individuals.
    Matched MeSH terms: Skin Physiological Phenomena
  20. Fadilah NIM, Rahman MBA, Yusof LM, Mustapha NM, Ahmad H
    Pharmaceutics, 2021 Feb 01;13(2).
    PMID: 33535623 DOI: 10.3390/pharmaceutics13020193
    The standard treatment of open wounds via the direct usage of therapeutic agents is not without limitations with respect to healing. Small peptides can create a favorable milieu for accelerating the healing of wounds. This study presents the potential of a novel fatty acid conjugated tetrapeptide (palmitic acid-glycine-aspartic acid-proline-histidine; Palmitoyl-GDPH) in alleviating wound healing. Tetracycline was employed as a standard control drug following its significance in wound healing including biologically active and antimicrobial effects. The peptide in liquid form was applied on to a 4 cm2 full thickness wound surgically induced at the dorsum of Sprague Dawley (SD) rats. The in vivo wound treatment with Palmitoyl-GDPH for eighteen days, histologically demonstrated an almost perfect healing exhibited by increased re-epithelialization, enhanced collagen deposition, and diminished scar formation compared to the controls. In addition, the well-developed epidermal-dermal junction and ultimate stimulation of hair follicle-growth in the Palmitoyl-GDPH treated group indicated the wound to have healed as functionally viable tissues. In general, the much lower hemogram values in the Palmitoyl-GDPH group indicated that the ongoing healing is en route to an earlier recovery. Additionally, the liver, kidney, and pancreas function biomarkers being within normal limits indicated the relatively non-toxic nature of Palmitoyl-GDPH at the used dosage. These results indisputably supported the great potential of this newly synthesized Palmitoyl-GDPH to be used as an effective therapeutic agent for wound healing (this actually means creating a new wound).
    Matched MeSH terms: Skin Physiological Phenomena
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