Posts Tagged ‘biology’

Monomelic Amyotrophy

Monomelic Amyotrophy  单肢肌肉萎缩


Monomelic amyotrophy (also known as MMA, Hirayama’s disease, Sobue diease or Juvenile nonprogressive amyotrophy) is an untreatable, focal, motor neuron disease that primarily affects young (15 – 25 year-old) males in India and Japan. MMA is marked by insidious onset of muscular atrophy, which stabilizes at a plateau after two to five years from which it neither improves nor worsens. There is no pain or sensory loss associated with MMA. Unlike other lower motor neuron diseases, MMA is not believed to be hereditary and fasciculations (involuntary muscle twitches) are rare.

Monomelic单肌萎缩 (又称MMA甲基丙烯酸甲酯平山郁夫症祖父江症少年无动态肌肉萎缩)是不治之症,这种聚焦的运动神经细胞疾病主要是影响印度和日本的青年男性(15 – 25岁)。甲基丙烯酸甲酯(MMA)的特点是隐匿性的肌肉萎缩发难,在二至五年后到了某一个高点就稳定下来,不再提高也不恶化。与甲基丙烯酸甲酯(MMA)相关的病症没有疼痛或丧失感觉,不像其他的较轻微运动神经元疾病,MMA不是遗传的,肌束颤动(不自主的肌肉抽搐)是罕见的。

EMG tests reveal loss of the nerve supply, or denervation, in the affected limb without conduction block (nerve blockage restricted to a small segment of the nerve). Increased sweating, coldness and cyanosis have been reported for a few patients, indicating involvement of the sympathetic nervous system.


While MMA will cause weakness and/or wasting in only one limb, EMG and NCV tests often show signs of reinnervation in the unaffected limbs.



Contents  目录

·      Treatment 治疗处理

·      Prognosis 病症诊断

·      Epidemiology 流行病学

·      External links 外部链接


Treatment  治疗处理

There is no cure for MMA. Treatment consists of muscle strengthening exercises and training in hand coordination.



Prognosis  病症诊断

The symptoms of MMA usually progress slowly for one to two years before reaching a plateau, and then remain stable for many years. Disability is generally slight. Rarely, the weakness progresses to the opposite limb. There is also a slowly progressive variant of MMA known as O’Sullivan-McLeod syndrome, which only affects the small muscles of the hand and forearm and has a slowly progressive course.



Epidemiology  流行病学

MMA occurs in males between the ages of 15 and 25. Onset and progression are slow. MMA is seen most frequently in Asia, particularly in Japan and India; it is much less common in North America.



External links  外部链接

monomelic_amyotrophy at NINDS。NINDS的单肢肌肉萎缩

MND Association。MND协会

Overview at Washington University  华盛顿大学的概况


Categories  分类

  • Motor neurone disease  运动神经元疾病

—— END ——


Source > Wikipedia at

Translated by > BlogHost

Word Count > approx. 350 words in English



April 21, 2012 Leave a comment

Osteology  骨骼学


Osteology is the scientific study of bones, practiced by osteologists. A subdiscipline of anatomy, anthropology, and archeology, osteology is a detailed study of the structure of bones, skeletal elements, teeth, morphology, function, disease, pathology, the process of ossification (from cartilaginous molds), the resistance and hardness of bones (biophysics), etc. often used by scientists with identification of human remains with regard to age, death, sex, growth, and development in a biocultural context.


Osteology and osteologists should not be confused with the alternative medical practice known as osteopathy and its practitioners, osteopaths.



Methods 方法

A typical analysis will include:

  • an inventory of the skeletal elements present
  • a dental inventory
  • aging data, based upon epiphyseal fusion and dental eruption (for subadults) and deterioration of the pubic symphysis or sternal end of ribs (for adults)
  • stature and other metric data
  • ancestry
  • non-metric traits
  • pathology and/or cultural modifications


  • 现成的骨骼元素清单
  • 牙科清单
  • 根据(未成年)骨骺融合和牙齿突长,以及(成人)耻骨愈合或肋骨的胸骨尾端的恶化得来的老化数据。
  • 身材和其他度量数据
  • 祖先族谱
  • 非度量的特征
  • 病理亦或文化


Applications 应用

Osteological approaches are frequently applied to investigations in disciplines such as forensic science, physical anthropology and archaeology, and has a place in research on topics including:


  • Health  健康
  • Demography  人口
  • Diet  饮食
  • Disease  疾病
  • activity patterns  活动模式
  • physique  体质
  • genetics of early populations  早期人口的遗传
  • population migration  人口迁徙
  • Ancient warfare  古代战争
  • social inequality  社会不平等
  • identification of unknown remains  鉴定不明的遗骸
  • criminal investigations  刑事侦查
  • war crimes  战争罪


See also 另见

  • Osteometric points  骨量点


External Links 外部链接

  • British Association for Biological Anthropology and Osteoarchaeology



Categories 分类

  • Osteology  骨骼学
  • Physical anthropology  体质人类学
  • Musculoskeletal system  肌肉骨骼
  • Anthropology  人类学

—— END ——


Source > Wikipedia at

Translated by > BlogHost

Word Count > approx.300 words in English



February 29, 2012 1 comment

Baleen   鲸须


Baleen or whalebone is a filter-feeder system inside the mouths of baleen whales. The baleen system works when a whale opens its mouth underwater and then water pours into the whale’s mouth. The whale then pushes the water out, and animals such as krill are filtered by the baleen and remain as food source for the whale. Baleen is similar to bristles and is made of keratin, the same substance found in human fingernails and hair. Some whales, such as the bowhead whale, have longer baleen than others. Others whales, such as the gray whale, only use one side of their baleen. These baleen bristles are arranged in plates across the upper jaw of the whale.


Depending on the species, a baleen plate can be 0.5 to 3.5 metres (1.6 to 11 ft) long, and weigh up to 90 kilograms (200 lb). Its hairy fringes are called baleen hair or whalebone-hair. They are also called baleen bristles, which in sei whales are highly calcified, calcification functioning to increase their stiffness. Baleen plates are broader at the gumline (base). The plates have been compared to sieves or Venetian blinds.



Contents  目录

  • Etymology  词源
  • Evolution  进化
  • Filter feeding  滤食性能
  • Human uses  人类用途
  • As a habitat  栖息地
  • References  参考资料
  • Further reading  其他读物


Etymology  词源

The word “baleen” derives from Early Modern English word meaning “whale”. This in turn derives from the Latin balaena, related to the Greek phalaina – both of these also mean “whale”.

“鲸须”一词源自于早期的现代英语单词,意思是“ 鲸鱼 ”,也是出自拉丁文的balaena,跟希腊文的phalaina有关,两者的意思都是”鲸鱼”.


Evolution  进化

The oldest true fossils of baleen are only 15 million years old, but baleen rarely fossilizes, and scientists believe it originated considerably earlier than that. This is indicated by baleen-related skull modifications being found in fossils from considerably earlier, including a buttress of bone in the upper jaw beneath the eyes, and loose lower jaw bones at the chin. Baleen is believed to have evolved around thirty million years ago, possibly from a hard, gummy upper jaw, like the one a Dall’s porpoise has. In fact, it resembles baleen closely at the microscopic level.

鲸须最古老的化石只有1千5百万年,但鲸须很少变成化石,因此科学家相信它的起源更早。这一点可以从更早以前发现的有鲸须的鲸鱼头骨化石看出来,尤其是眼睛下方上颚骨里的一排骨头,以及下巴松动的下颚骨。科学家相信鲸须在大约三千万年前进化而成,有可能是从硬的上颚骨牙龈那里长出来,像达尔江豚也有的。 事实上,在微观层面上它更像鲸须。

Many early baleen whales also had teeth, but these were probably used only peripherally, or perhaps not at all (again like Dall’s porpoise, which catches squid and fish by gripping them against its hard upper jaw).



Filter Feeding  滤食性能

A whale’s baleen plates play the most important role in its filter-feeding process. In order to feed, a baleen whale opens its mouth widely and scoops in dense shoals of prey (such as krill, copepods, small fish and sometimes birds that happen to be near the shoals), together with large volumes of water. It then partly shuts its mouth and presses its tongue against its upper jaw, forcing the water to pass out sideways through the baleen, thus sieving out the prey which it then swallows.



Human Uses  人类用途

People formerly used baleen for making numerous items where flexibility and strength were required, including collar stiffeners, buggy whips and parasol ribs, and as corset stays. It was commonly used to crease paper; its flexibility kept it from damaging the paper. It was also occasionally used in cable-backed bows. Synthetic materials are now usually used for similar purposes, especially plastic and fibre glass. Baleen was frequently used in the 18th and early 19th centuries as the handle for silver punch or toddy ladles. It was chosen for this use because of its insulating qualities. Baleen plates are also used by indigenous people to create fine crafts.



As a Habitat  栖息地

Baleen serves as a habitat for some species from the gastropod families Pyropeltidae, Cocculinidae, Osteopeltidae and Neolepetopsidae.



See Also  另见

  • John Henry Devereux South Carolina architect who used whale jaw bones to adorn the largest mansion on Sullivan’s Island.

南卡罗来纳州的建筑师John Henry Devereux约翰亨利德弗罗用鲸鱼颚骨来装饰Sullivan苏里曼岛上最大的豪宅。

  • Cetaceans   鲸类动物
  • Whale Products  鲸鱼产品


—— END ——


Source > Wikipedia at

Translated by > BlogHost

Word Count > approx. 630 words in English

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