Hasil untuk "physics.med-ph"

H. Birks, J. Line, S. Juggins et al.

Y. Ohno, K. Maehashi, Y. Yamashiro et al.

R. Cardone, V. Casavola, S. Reshkin

Eun Seong Lee, Zhong-gao Gao, Y. Bae

Y. Urano, D. Asanuma, Y. Hama et al.

H. Lambers, S. Piessens, A. Bloem et al.

T. D. Brock, K. M. Brock, R. Belly et al.

S. Duncan, P. Louis, J. Thomson et al.

M. Schmid-Wendtner, H. Korting

The ‘acid mantle’ of the stratum corneum seems to be important for both permeability barrier formation and cutaneous antimicrobial defense. However, the origin of the acidic pH, measurable on the skin surface, remains conjectural. Passive and active influencing factors have been proposed, e.g. eccrine and sebaceous secretions as well as proton pumps. In recent years, numerous investigations have been published focusing on the changes in the pH of the deeper layers of the stratum corneum, as well as on the influence of physiological and pathological factors. The pH of the skin follows a sharp gradient across the stratum corneum, which is suspected to be important in controlling enzymatic activities and skin renewal. The skin pH is affected by a great number of endogenous factors, e.g. skin moisture, sweat, sebum, anatomic site, genetic predisposition and age. In addition, exogenous factors like detergents, application of cosmetic products, occlusive dressings as well as topical antibiotics may influence the skin pH. Changes in the pH are reported to play a role in the pathogenesis of skin diseases like irritant contact dermatitis, atopic dermatitis, ichthyosis, acne vulgaris and Candida albicans infections. Therefore, the use of skin cleansing agents, especially synthetic detergents with a pH of about 5.5, may be of relevance in the prevention and treatment of those skin diseases.

R. Feely, S. Alin, J. Newton et al.

H. Bai, Chun Xing Li, Xiaolin Wang et al.

Faheem Muhammad, Mingyi Guo, Wenxiu Qi et al.

Xiaomeng Zhang, Yuxiang Lin, R. Gillies

Xu Zhang, M. Servos, Juewen Liu

I. Robey, B. Baggett, N. Kirkpatrick et al.

Dhammika Weerakkody, A. Moshnikova, Mak S. Thakur et al.

T. H. Nguyen, Thillainathan Venugopala, Shuying Chen et al.

The design, development and evaluation of an optical fibre pH sensor for monitoring pH in the alkaline region are discussed in detail in this paper. The design of this specific pH sensor is based on the pH induced change in fluorescence intensity of a coumarin imidazole dye which is covalently attached to a polymer network and then fixed to the distal end of an optical fibre. The sensor provides a response over a pH range of 10.0–13.2 with an acceptable response rate of around 50 min, having shown a very good stability over a period of longer than 20 months thus far. The sensor has also demonstrated little cross-sensitivity to ionic strength (IS) and also excellent photostability through a series of laboratory tests. These features make this type of sensor potentially well suited for in situ long term monitoring of pH in concrete structures, to enhance structural monitoring in the civil engineering sector.

A. Martinière, E. Bassil, É. Jublanc et al.

J. Beattie, Alex M. Djerdjev, Angus A Gray-Weale et al.

S. Jha, Jessica M. Snell, S. R. Sheftic et al.