不一样的旅游

13年前,我第一次拜谒水洞沟,为的是开发一种不一样的旅游。当时,久富盛名的同心化石产地因盗采滥挖而破坏严重。宁夏回族自治区地质部门希望在当地建立化石保护区对化石资源和化石产地进行有效的保护,同时建设相关的博物馆,开展古生物科普和旅游,以使化石资源得到更合理、可持续的利用。受其邀请,我们古脊椎所(全称是"中国科学院古脊椎动物与古人类研究所")委派叶     

Identification of Immunoreactive Material in Mammoth Fossils

The fossil record represents a history of life on this planet. Attempts to obtain molecular information from this record by analysis of nucleic acids found within fossils of extreme age have been unsuccessful or called into question. However, previous studies have demonstrated the long-term persistence of peptides within fossils and have used antibodies to extant proteins to demonstrate antigenic material. In this study we address two questions: Do immunogenic/antigenic materials persist in fossils? and; Can fossil material be used to raise antibodies that will cross-react with extant proteins? We have used material extracted from a well-preserved 100000-300000-year-old mammoth skull to produce antisera. The specificity of the antisera was tested by ELISA, western blotting, and immunohistochemistry. It was demonstrated that antisera reacted specifically with the fossils and not the surrounding sediments. Reactivity of antisera with modern proteins and tissues was also demonstrated, as was the ability to detect evolutionary relationships via antibody-antigen interactions. Mass spectrometry demonstrated the presence of amino acids and specific peptides within the fossil. Peptides were purified by anion-exchange chromatography and sequenced by tandem mass spectrometry. The collagen-derived peptides may have been the source of at least some of the immunologic reactivity, but the antisera identified molecules that were not observed by mass spectrometry, indicating that immunologic methods may have greater sensitivity. Although the presence of peptides and amino acids was demonstrated, the exact nature of the antigenic material was not fully clarified. This report demonstrates that antibodies may be used to obtain information from the fossil record.     

Mammoth interatrial septal aneurysm in the ICE age

Background

Subaortic and midventricular hypertrophic cardiomyopathy in a patient with extreme segmental hypertrophy exceeding the usual maximum wall thickness reported in the literature is a rare phenomenon.

Case Presentation

A 19-year-old man with recently diagnosed hypertrophic cardiomyopathy (HCM) was referred for sudden death risk assessment. The patient had mild exertional dyspnea (New York Heart Association functional class II), but without syncope or chest pain. There was no family history of HCM or sudden death. A two dimensional echocardiogram revealed an asymmetric type of LV hypertrophy; anterior ventricular septum = 49 mm; posterior ventricular septum = 20 mm; anterolateral free wall = 12 mm; and posterior free wall = 6 mm. The patient had 2 types of obstruction; a LV outflow obstruction due to systolic anterior motion of both mitral leaflets (Doppler-estimated 38 mm Hg gradient at rest); and a midventricular obstruction (Doppler-estimated 43 mm Hg gradient), but without apical aneurysm or dyskinesia. The patient had a normal blood pressure response on exercise test and no episodes of non-sustained ventricular tachycardia in 24-h ECG recording. Cardiac MRI showed a gross late enhancement at the hypertrophied septum. Based on the extreme degree of LV hypertrophy and the myocardial hyperenhancement, an implantation of a cardioverter-defibrillator was recommended prophylactically for primary prevention of sudden death.

Conclusion

Midventricular HCM is an infrequent phenotype, but may be associated with an apical aneurysm and progression to systolic dysfunction (end-stage HCM).     

支撑美丽的是和谐

眼前的老荷叶寨,不也是一个本底吗?它记录着人与自然之间不可失去的和谐得到保护区管理局的特殊许可,我来到荷叶坝背后山上的老寨子。踏出车门,诗画一般的村寨风光一下子就惊呆了每一个人:雪山森林环抱着分散在山坡上的几个小小村寨,每个寨子都是由错落有致的藏式木楼和随风飘扬着的红、黄、蓝、白、绿色的经幡彩     

经历了大山大水震撼的男人才完美

“对抗自然，等于搬起石头打天”，摄影师的眼光和想法总是浪漫的，就算是在川藏线上摸爬滚打了这么多年的戴成华也不例外。除了军人的身份，他还用相机记录了这条让人又爱又恨的路。在雅安兵站部，我们见到了他。他的房间里满是放大了的川藏线的照片，摆放着一路捡回来的各色石头透出对自然的眷恋。和跑了多年的战士们一样，川藏线弄坏了他的身体。拔掉输液针头，他接受我们的访问，却没有抱怨，只是十分平淡地说，“经历了川藏线，经历了大山大水震撼的男人才算是完美了”。[编者按]     

不同自然地带杉木林的生物生产力

本文对不同自然地带杉木林的生物生产力进行了比较,结果表明：中带(相当于中亚热带)生产力最高,其后依次为南带(相当于南亚热带)和北带(相当于北亚热带)。     

Dynamics of Self-Thinning Plant Stands

The growth of plants in even-aged, pure stands and the declinein the number of these plants are represented with a set ofS-system differential equations. The S-system representationcaptures the observed interdependence between average size andnumber of plants, demonstrates how a plant stand approachesthe well-established 3/2 power relationship between number andsize, and also accounts for the observation that in stands ofperennial species, old plants usually remain smaller than predictedby the relationship. The model includes, as special cases, earliermodels that only partially represent the mutual dependence betweennumber and average size. The S-system model incorporates well-knowngrowth laws, and thus circumvents the problem of identifyingthe most appropriate growth and decline functions in the analysisof actual data. For particular parameter settings, the S-systemcan be solved analytically to yield explicit closed-form relationshipsbetween the numbers and sizes of plants, not only in the rangewhere the stand dynamics moves along the size-limiting relationship,but also for large numbers of small plants and small numbersof large plants. Growth, plant stands, self-thinning, 3/2 power rule, S-system model