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61.
Thore J. Bergman Abebaw Azanaw Haile Jacinta C. Beehner 《International journal of primatology》2018,39(6):1005-1008
The term “baboon” is the common name used for a subset of terrestrial Cercopithecines with large bodies and protruding snouts. Although the application of the term has changed considerably over the years, we argue that common names, such as “baboon,” should reflect the current state of phylogenetic knowledge. This practice promotes a broader understanding of taxonomic diversity that can impact decisions related to ecotourism, wildlife management, and conservation. Thus, we argue that “baboon” should be used only for members of the genus Papio. 相似文献
62.
Chronic peptic ulceration is a disease process in transition. During the past two decades, the disease has changed in its incidence, in its presentation and in its medical consequences. The pathogenesis of acid-peptic disease has been the major focus of numerous investigations, and major advances in understanding basic gastric physiology have led to specific and increasingly effective therapeutic approaches. With the introduction of H2-receptor antagonists, the treatment of peptic ulceration has been radically altered, and many new therapies await clinical trial. Surgeons treating gastroduodenal ulceration will require greater knowledge of gastric physiology and an increasingly refined appreciation of both the power and limitations of various medical and surgical therapies. 相似文献
63.
Regulation of interaction of the iron-responsive element binding protein with iron-responsive RNA elements. 总被引:34,自引:3,他引:31 下载免费PDF全文
D J Haile M W Hentze T A Rouault J B Harford R D Klausner 《Molecular and cellular biology》1989,9(11):5055-5061
The 5' untranslated region of the ferritin heavy-chain mRNA contains a stem-loop structure called an iron-responsive element (IRE), that is solely responsible for the iron-mediated control of ferritin translation. A 90-kilodalton protein, called the IRE binding protein (IRE-BP), binds to the IRE and acts as a translational repressor. IREs also explain the iron-dependent control of the degradation of the mRNA encoding the transferrin receptor. Scatchard analysis reveals that the IRE-BP exists in two states, each of which is able to specifically interact with the IRE. The higher-affinity state has a Kd of 10 to 30 pM, and the lower affinity state has a Kd of 2 to 5 nM. The reversible oxidation or reduction of a sulfhydryl is critical to this switching, and the reduced form is of the higher affinity while the oxidized form is of lower affinity. The in vivo rate of ferritin synthesis is correlated with the abundance of the high-affinity form of the IRE-BP. In lysates of cells treated with iron chelators, which decrease ferritin biosynthesis, a four- to fivefold increase in the binding activity is seen and this increase is entirely caused by an increase in high-affinity binding sites. In desferrioxamine-treated cells, the high-affinity form makes up about 50% of the total IRE-BP, whereas in hemin-treated cells, the high-affinity form makes up less than 1%. The total amount of IRE-BP in the cytosol of cells is the same regardless of the prior iron treatment of the cell. Furthermore, a mutated IRE is not able to interact with the IRE-BP in a high-affinity form but only at a single lower affinity Kd of 0.7 nM. Its interaction with the IRE-BP is insensitive to the sulfhydryl status of the protein. 相似文献
64.
选择容量价值:一个新的生态系统服务价值指标 总被引:1,自引:0,他引:1
对生态系统服务进行价值评估有助于落实生态系统的科学管理和推动生态补偿的科学实施。然而,传统的生态系统服务价值评估方法在管理实践应用中存在明显的局限性。为了规避这些局限性,另辟一条对生态系统服务价值评估的新思路,提出了描述生态系统服务价值的新指标——"选择容量价值"。选择容量价值以两个事实为基本依据:1)如果失去了任何一项生存所必需的生态系统服务(比如氧气、水),那么人类就无法生存,亦即人类经济社会活动所产生的价值是建立在消费该生态系统服务的基础上的;2)如果没有人类活动的存在,那么生态系统就给人类提供不了任何价值,亦即生态系统服务价值的度量是建立在生态系统服务所支持的人类经济社会活动所产生的价值上的。选择容量价值是指,一项人类生存生产所必需的生态系统服务,其总量为消费该生态系统服务的消费活动所提供的选择自由度(即选择容量)与该消费活动所产生的经济社会活动总价值的乘积,用非货币单位来计量。通过一个案例——对珠江流域的水资源供应的选择容量价值的估算,揭示选择容量价值对理解和量化生态系统服务价值的新洞察。结果显示,选择容量价值能够直观而综合地反映生态系统服务总量、生态系统服务消费量、社会经济活动总价值之间的关系,为理解和量化生态系统服务价值提供新视角,也为理解和量化上下游间的生态系统服务输移的价值核算提供新思路。这对当前的生态系统服务价值研究范式具有补充作用。 相似文献
65.
Zhenbin Wang Lin Wang Shiman Lin Qiufang Liang Zhujun Shi Junmin Xu Haile Ma 《Biotechnology and Bioprocess Engineering》2014,19(5):935-941
The collagen in Amur sturgeon muscle was isolated using sodium chloride (salt-solubilized collagen, SSC, 3.02%), followed by acetic acid (acid-solubilized collagen, ASC, 31.56%) and then pepsin (pepsin-solubilized collagen, PSC, 58.49%). The collagens appeared to be dense sheet-like film linked by random-coiled filaments under SEM. There was no obvious difference in denaturation temperature (about 33°C) assessed by CD, while the melting temperature of SSC (115.82°C) was significantly lower than ASC and PSC (120.23 and 118.80°C, respectively) determined by DSC. SDS-PAGE showed that the collagens were mainly type I with similar amino acid profiles. FTIR confirmed the triple helical structure of the collagens, and indicated more hydrogen bond in PSC and more intermolecular crosslinks in ASC. These results provide some basis for elucidating the function of collagen in the development of meat texture during postmortem aging and processing. 相似文献
66.
67.
Li CH Irmer H Gudjonsdottir-Planck D Freese S Salm H Haile S Estévez AM Clayton C 《RNA (New York, N.Y.)》2006,12(12):2171-2186
The genome of the kinetoplastid parasite Trypanosoma brucei encodes four homologs of the Saccharomyces cerevisiae 5'-->3' exoribonucleases Xrn1p and Xrn2p/Rat1p, XRNA, XRNB, XRNC, and XRND. In S. cerevisiae, Xrn1p is a cytosolic enzyme involved in degradation of mRNA, whereas Xrn2p is involved in RNA processing in the nucleus. Trypanosome XRND was found in the nucleus, XRNB and XRNC were found in the cytoplasm, and XRNA appeared to be in both compartments. XRND and XRNA were essential for parasite growth. Depletion of XRNA increased the abundances of highly unstable developmentally regulated mRNAs, perhaps by delaying a deadenylation-independent decay pathway. Degradation of more stable or unregulated mRNAs was not affected by XRNA depletion although a slight decrease in average poly(A) tail length was observed. We conclude that in trypanosomes 5'-->3' exonuclease activity is important in degradation of highly unstable, regulated mRNAs, but that for other mRNAs another step is more important in determining the decay rate. 相似文献
68.
Species composition and diversity of small Afromontane forest fragments in northern Ethiopia 总被引:1,自引:0,他引:1
Raf Aerts Koen Van Overtveld Mitiku Haile Martin Hermy Jozef Deckers Bart Muys 《Plant Ecology》2006,187(1):127-142
In the highlands of northern Ethiopia, remnants of the original Afromontane forest vegetation are largely restricted to church yards and other sacred groves in a matrix of cropland and semiarid degraded savanna. To assess the potential for natural forest regeneration, species composition and diversity of all forest fragments (10) in a study area of 13,000 ha were analyzed in relation to environmental and soil variables. Using a random design and a density of approximately one plot per 2 ha in all fragments, 31 20×20 m plots were sampled. Indicator species analysis and MRPP tests yielded five communities representing two forest types and one degraded savanna habitat. The forest fragments had a species-poor tree and shrub community in which plots were rather homogeneous and most species abundant. NMDS and analysis of variance indicated that a topographical gradient correlated to soil phosphorus, soil depth, stoniness and the proximity to the river system explained the major differences in species composition and separated moist and dry Afromontane forest communities. The grazing intensity further partitioned the habitats. Present communities and their environmental correlates indicate that the secondary climax forest in the area probably consisted of dry Afromontane forest interlaced by broad strips of moist Afromontane forest along rivers and streams and not a continuous, mono-dominant Juniperus forest as is often presumed. Negative effects of the degraded matrix on forest fragments increased with decreasing patch area and increasing shape irregularity. Nevertheless, all remaining fragments are important for their role in the landscape ecology of the region as refuges and species pools and should be protected and managed accordingly. If seed dispersal from forest fragments into exclosures and subsequent tree recruitment are both successful, the vegetation type most likely to establish is Afromontane savanna woodland, and if managed properly, eventually dry Afromontane forest may arise. Increasing the size of small patches and placing forest plantations and exclosures in the vicinity of small forest fragments is expected to yield the most immediate results. This approach may increase the likelihood of patch colonisation by frugivorous forest birds and thus foster the regeneration of native woody species. 相似文献
69.
Margaret E. Kruk Andreas Wladis Naboth Mbembati S. Khady Ndao-Brumblay Renee Y. Hsia Moses Galukande Sam Luboga Alphonsus Matovu Helder de Miranda Doruk Ozgediz Ana Romàn Qui?ones Peter C. Rockers Johan von Schreeb Fernando Vaz Haile T. Debas Sarah B. Macfarlane 《PLoS medicine》2010,7(3)
Background
There is a growing recognition that the provision of surgical services in low-income countries is inadequate to the need. While constrained health budgets and health worker shortages have been blamed for the low rates of surgery, there has been little empirical data on the providers of surgery and cost of surgical services in Africa. This study described the range of providers of surgical care and anesthesia and estimated the resources dedicated to surgery at district hospitals in three African countries.Methods and Findings
We conducted a retrospective cross-sectional survey of data from eight district hospitals in Mozambique, Tanzania, and Uganda. There were no specialist surgeons or anesthetists in any of the hospitals. Most of the health workers were nurses (77.5%), followed by mid-level providers (MLPs) not trained to provide surgical care (7.8%), and MLPs trained to perform surgical procedures (3.8%). There were one to six medical doctors per hospital (4.2% of clinical staff). Most major surgical procedures were performed by doctors (54.6%), however over one-third (35.9%) were done by MLPs. Anesthesia was mainly provided by nurses (39.4%). Most of the hospital expenditure was related to staffing. Of the total operating costs, only 7% to 14% was allocated to surgical care, the majority of which was for obstetric surgery. These costs represent a per capita expenditure on surgery ranging from US$0.05 to US$0.14 between the eight hospitals.Conclusion
African countries have adopted different policies to ensure the provision of surgical care in their respective district hospitals. Overall, the surgical output per capita was very low, reflecting low staffing ratios and limited expenditures for surgery. We found that most surgical and anesthesia services in the three countries in the study were provided by generalist doctors, MLPs, and nurses. Although more information is needed to estimate unmet need for surgery, increasing the funds allocated to surgery, and, in the absence of trained doctors and surgeons, formalizing the training of MLPs appears to be a pragmatic and cost-effective way to make basic surgical services available in underserved areas. Please see later in the article for the Editors'' Summary 相似文献70.
Hu Liu Cyrille Kuhn Frederic Feru Suzanne L. Jacques Gayatri D. Deshmukh Ping Ye Glen R. Rennie Theresa Johnson Steven Kazmirski Simon Low Rocco Coli Yuan-hua Ding Alan C. Cheng Haile Tecle Jessie M. English Robert Stanton Joe C. Wu 《Bioorganic & medicinal chemistry letters》2010,20(16):4885-4891
By targeting an extended region of the conventional ‘DFG-out’ pocket of p38α, while minimizing interactions with the specificity pocket and eliminating interactions with the adenine binding site, we are able to design and synthesize a number of pyrazole-urea based DFG-out p38α inhibitors with good potencies, and excellent selectivity. 相似文献