家 庭 防 盜 系 統

[[abstract]]在本篇專題中我們是利用8051單晶片配合光敏電阻及蜂鳴器組成兩大功能。首先，是隨機燈光開啟系統，當光敏電阻感測天色變暗時，屋內的隨機燈光系統便會啟動，此時隨著時間的推移，屋內的電燈亦會隨時間開啟、關閉。同時我們採用的是隨機模式，每次燈光開啟的模式都不相同，避免被人觀察到異樣。第二項功能為警報器，此功能由安裝在大門的磁簧開關控制，當大門受外力開啟時，警報器就會開始啟動，且大門如馬上關上警報器也不會關閉，而是持續一段時間後才停止。透過這兩個保全裝置，可以讓使用者安心出外旅遊或是出

Pigmentation+in+the+Skin+of+Silky+Chickens

黑色素(melanin)為脊椎動物之主要生物色素，通常存在於皮膚或是毛髮，它是由黑色素細胞(melanocytes)中的特殊胞器－黑色素體(melanosomes)所合成。哺乳動物之黑色素細胞存在於表皮和毛囊，而禽類通常位於羽毛中。絲羽烏骨雞為禽類的自然突變種，黑色素會堆積在真皮以及結締組織中。因此，本文之目的在探討絲羽烏骨雞色素過度沉積的過程和原因。在烏骨雞胚胎發育過程中，由神經管衍生的神經嵴細胞(neural crest cells)會分化成黑色素母細胞(melanoblasts)，黑色素母細胞會隨著神經細胞的遷徙，經由神經管的背側和腹部到達胚的腹部。絲羽烏骨雞的黑色素母細胞之所以可以移動至腹部是由於其缺少了神經阻礙物分子，而此神經阻礙物分子在棕色來航雞的胚胎發育過程中，會明顯地形成一道障壁以抑制神經嵴細胞和黑色素母細胞入侵胚胎腹部。在絲羽烏骨雞胚胎發育第6至第19天，拉長的黑色素細胞其細胞質會彼此連接並在真皮表面的纖維層下形成網狀物。綜合上述，絲羽烏骨雞之黑色皮膚是源自於缺少神經阻礙物分子，導致黑色素母細胞遷徙至胚的腹部並入侵中胚層，在真皮中，黑色素母細胞會分化形成黑色素細胞，黑色素母細胞會存在於真皮深處及真皮表面的纖維層而形成皮膚的顏色。In vertebrates, melanin is the major factor causing pigmentation in skin or hair follicles. Melanin is produced by melanosomes, the special organelles in melanoctyes, and secreted to adjacent keratinocytes. In birds, epidermal melanocytes are usually located only in the feathers, while they are found in the epidermis and hair follicles in mammals. The Silky chickens show extensive pigmentation in the dermis and connective tissues of internal organs. Due to this unusual pattern of pigmentation, the Silky fowl has been useful for investigation of the processes related to pigmentation. In Silky chickens, melanoblasts derived from neural crest cells would emigrate from the neural tube through dorsolateral and ventral paths and then reach visceral regions of the embryo. The ability of melanoblasts in the Silkie embryos to migrate ventrally is correlated with a lack of peanut agglutinin binding barrier tissues, which are present in the Lightbrown Leghorn embryos. At later stages of development (on Day 6-19), fully differentiated melanocytes are elongated with many long cytoplasmic processes and formed a meshwork underneath a layer of collagen and elastic fibers which are constructed in the superficial dermis. In conclusion, black skin of Silky chickens is generated by the atypical migration of melanoblasts, and this unusual migratory pattern might be caused by a loss of barrier molecules. Thus the melanoblasts are differentiated and distributed below the collagen layer in dermis and then causing the skin pigmentation