Analysis of symmetricity in the three different (sagittal, transverse and frontal) planes in generalized nonsegmental vitiligo.

BACKGROUND: Nonsegmental vitiligo is defined as being "often symmetrical", however, no work has tackled the point as to how valid it is to depend upon the concept of symmetricity in generalized nonsegmental vitiligo. AIMS: To investigate vitiligo symmetry, taking into account sites of predilection, the clinical characteristics of patients were studied. METHODS: This multicentric study included 712 nonsegmental vitiligo patients with 2876 examined lesions. Three models were drawn for each patient. Sagittal, transverse and frontal planes were drawn to divide the body into right/left, upper/lower and anterior/posterior halves respectively. Patients were examined by Wood's light and analyzed for symmetry. RESULTS: Bilateral involvement was present in 78% (P < 0.001). Studying the similarity of clinical involvement in the upper and lower body parts revealed that such similarity was present in 38%, with a significant positive association in some areas. Studying clinical similarity in the anteroposterior distribution pattern revealed a significant positive association in 11%. LIMITATIONS: Relatively low number of patients. CONCLUSIONS: We found significant bilateral symmetry in the lesions of 78% of vitiligo patients. Our work could aid in drawing the anticipated vitiligo map in patients with active disease, helping in increasing our understanding of the clinical behaviour of this disease.

Noise utilization as an approach for reducing energy consumption in street lighting.

Noise is considered as one of the challenging problems in big cities. However, this noise could be utilized in producing energy especially in dense urban areas. Sound as a form of mechanical energy, it can be converted to electric energy through many approaches including heating, by using the diaphragm and through using piezoelectric materials. This research aims at utilizing noise through using piezoelectric materials as an approach of conversion to produce green sustainable electric energy that can be used to decrease the energy consumption from non-renewable sources and utilizing this energy in street lighting. The study was carried in three bus stations in Alexandria by having measurements during weekdays and weekends in order to study the noise produced in the selected stations and the amount of electric energy that could be produced and utilized in street lighting. The noise level index LDEN was calculated for each of the three selected locations. The equivalent noise level values were always exceeding the limits through the day, evening and night. At daytime they ranged between 75-85 dB which is higher that the permissible limit by 10-20 dB, at evening they ranged from 80-85 dB which is also higher than the permissible limit with 20-25 dB and at the night they ranged from 75-80 dB which is higher by 20-25 dB than the permissible limit. The research concluded that utilizing noise using the piezoelectric material is successful. The electric energy produced from an area of 1.45 m2 containing 690 piezoelectric QB220-503YB transducers at each of the selected stations was about 0.024 watt hr. This amount of electric energy is too small to be used in an application. So the application area should be maximized to hundreds of square meters to produce beneficial electric energy that can be used in lighting 1 LED street lamp or it can be stored and used when needed in applications that use greater amount of electric energy and this would help in reducing the energy consumed.