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101.
Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} In 1968 and 1973 in southwestern Idaho, 275 Uta stansburiana were collected. Uta occupies low hills with rocky outcrops and flat sparse vegetation consisting of the following shrubs: Artemisia tridentata, Grayia spinosa, Atriplex confertifolia, Chrysothamnus nauseosus, and Atriplex canescens. Emergence from hibernation occurs from mid-March to early April and the first yolked follicles appear in early April, with oviducal eggs present in late April. Testicular cycle begins with the emergence of males, and spermatozoa are produced from April through July. Uta reaches sexual maturity in one year at a SVL of 40.0 mm in males and 43 mm in females. Overall clutch size is 3.75 eggs (1–2 clutches per year). Fat body size at emergence is not known, but what is present shows a decline in males and females until July, when a substantial increase occurs. Sex ratios are about 1:1 in all months and seasons except June 1968, according to chi-square analysis. 相似文献
102.
Coastal erosion at central Whidbey Island reveals a cross-section view of dune sands that contain the only known record of animals that inhabited the Pacific Northwest coast during the early Holocene. Mammal fossils include bones and teeth of deer, wolf, brown bear, and several species of rodents. A deer vertebra from basal beds yielded a 14 C age of 8840 ± 50 yr BP. The faunal diversity suggests that the region was repopulated relatively quickly following the final retreat of the Cordilleran sheet. This paleofauna was quite different from that of the late Pleistocene, when the region was inhabited by mammoth, musk oxen, giant sloth, and other large mammals. Avian remains include hawks, geese, and seabirds, 3 groups that occupied quite different ecological niches. Early Holocene bird fossils from Whidbey Island are dissimilar to late Pleistocene avifaunas from inland sites in California and Oregon, evidence that the coastal environment offered habitat conditions quite unlike those of interior wetlands. 相似文献
103.
AMOAKO George ZHOU Ming YE RiAn ZHUANG LiZhou YANG XiaoHong SHEN ZhiYong 《科学通报(英文版)》2013,58(24):3019-3022
For about three decades, DNA-based nanotechnology has been undergoing development as an assembly method for nanostructured materials. The DNA origami method pioneered by Rothemund paved the way for the formation of 3D structures using DNA self assembly. The origami approach uses a long scaffold strand as the input for the self assembly of a few hundred staple strands into desired shapes. Herein, we present a 3D origami "roller" (75 nm in length) designed using caDNAno software. This has the potential to be used as a template to assemble nanoparticles into different pre-defined shapes. The "roller" was characterized with agarose gel electrophoresis, atomic force microscopy (AFM) and transmission electron microscopy (TEM). 相似文献
104.
Svenja D. Steinbrink Carlo Pergola Ulrike Bühring Sven George Julia Metzner Astrid S. Fischer Ann-Kathrin Häfner Joanna M. Wisniewska Gerd Geisslinger Oliver Werz Dieter Steinhilber Thorsten J. Maier 《Cellular and molecular life sciences : CMLS》2010,67(5):797-806
Sulindac is a non-selective inhibitor of cyclooxygenases (COX) used to treat inflammation and pain. Additionally, non-COX targets may account for the drug’s chemo-preventive efficacy against colorectal cancer and reduced gastrointestinal toxicity. Here, we demonstrate that the pharmacologically active metabolite of sulindac, sulindac sulfide (SSi), targets 5-lipoxygenase (5-LO), the key enzyme in the biosynthesis of proinflammatory leukotrienes (LTs). SSi inhibited 5-LO in ionophore A23187- and LPS/fMLP-stimulated human polymorphonuclear leukocytes (IC50 ≈ 8–10 μM). Importantly, SSi efficiently suppressed 5-LO in human whole blood at clinically relevant plasma levels (IC50 = 18.7 μM). SSi was 5-LO-selective as no inhibition of related lipoxygenases (12-LO, 15-LO) was observed. The sulindac prodrug and the other metabolite, sulindac sulfone (SSo), failed to inhibit 5-LO. Mechanistic analysis demonstrated that SSi directly suppresses 5-LO with an IC50 of 20 μM. Together, these findings may provide a novel molecular basis to explain the COX-independent pharmacological effects of sulindac under therapy. 相似文献
105.
106.
The molten eutectic mixture of magnesium,sodium and potassium chlorides(Mg Cl2–Na Cl–KCl) has inappreciable solubility for oxide ions,and can help disengage a carbon anode from the oxide ions generated at a metal oxide cathode,and effectively avoid carbon dioxide formation.This "disengaging strategy" was successfully demonstrated in electro-reduction of solid oxides of zirconium and tantalum.It has led to significantly higher current efficiency(93%),and lower energy consumption(1.4 k W h kg 1) in electrolysis of tantalum oxide to tantalum metal compared to the conventional electrolysis in molten calcium chloride(e.g.78% and 2.4 k W h/kg-Ta). 相似文献
107.
Van Heuverswyn F Li Y Neel C Bailes E Keele BF Liu W Loul S Butel C Liegeois F Bienvenue Y Ngolle EM Sharp PM Shaw GM Delaporte E Hahn BH Peeters M 《Nature》2006,444(7116):164
Chimpanzees (Pan troglodytes troglodytes) from west central Africa are recognized as the reservoir of simian immunodeficiency viruses (SIVcpzPtt) that have crossed at least twice to humans: this resulted in the AIDS pandemic (from human immunodeficiency virus HIV-1 group M) in one instance and infection of just a few individuals in Cameroon (by HIV-1 group N) in another. A third HIV-1 lineage (group O) from west central Africa also falls within the SIVcpzPtt radiation, but the primate reservoir of this virus has not been identified. Here we report the discovery of HIV-1 group O-like viruses in wild gorillas. 相似文献
108.
Many essential cellular processes are carried out by complex biological machines located in the cell membrane. The bacterial flagellar motor is a large membrane-spanning protein complex that functions as an ion-driven rotary motor to propel cells through liquid media. Within the motor, MotB is a component of the stator that couples ion flow to torque generation and anchors the stator to the cell wall. Here we have investigated the protein stoichiometry, dynamics and turnover of MotB with single-molecule precision in functioning bacterial flagellar motors in Escherichia coli. We monitored motor function by rotation of a tethered cell body, and simultaneously measured the number and dynamics of MotB molecules labelled with green fluorescent protein (GFP-MotB) in the motor by total internal reflection fluorescence microscopy. Counting fluorophores by the stepwise photobleaching of single GFP molecules showed that each motor contains approximately 22 copies of GFP-MotB, consistent with approximately 11 stators each containing two MotB molecules. We also observed a membrane pool of approximately 200 GFP-MotB molecules diffusing at approximately 0.008 microm2 s(-1). Fluorescence recovery after photobleaching and fluorescence loss in photobleaching showed turnover of GFP-MotB between the membrane pool and motor with a rate constant of the order of 0.04 s(-1): the dwell time of a given stator in the motor is only approximately 0.5 min. This is the first direct measurement of the number and rapid turnover of protein subunits within a functioning molecular machine. 相似文献
109.
The origins and the future of microfluidics 总被引:23,自引:0,他引:23
Whitesides GM 《Nature》2006,442(7101):368-373
The manipulation of fluids in channels with dimensions of tens of micrometres--microfluidics--has emerged as a distinct new field. Microfluidics has the potential to influence subject areas from chemical synthesis and biological analysis to optics and information technology. But the field is still at an early stage of development. Even as the basic science and technological demonstrations develop, other problems must be addressed: choosing and focusing on initial applications, and developing strategies to complete the cycle of development, including commercialization. The solutions to these problems will require imagination and ingenuity. 相似文献
110.
Muzny DM Scherer SE Kaul R Wang J Yu J Sudbrak R Buhay CJ Chen R Cree A Ding Y Dugan-Rocha S Gill R Gunaratne P Harris RA Hawes AC Hernandez J Hodgson AV Hume J Jackson A Khan ZM Kovar-Smith C Lewis LR Lozado RJ Metzker ML Milosavljevic A Miner GR Morgan MB Nazareth LV Scott G Sodergren E Song XZ Steffen D Wei S Wheeler DA Wright MW Worley KC Yuan Y Zhang Z Adams CQ Ansari-Lari MA Ayele M Brown MJ Chen G Chen Z Clendenning J Clerc-Blankenburg KP Chen R Chen Z Davis C Delgado O Dinh HH Dong W 《Nature》2006,440(7088):1194-1198
After the completion of a draft human genome sequence, the International Human Genome Sequencing Consortium has proceeded to finish and annotate each of the 24 chromosomes comprising the human genome. Here we describe the sequencing and analysis of human chromosome 3, one of the largest human chromosomes. Chromosome 3 comprises just four contigs, one of which currently represents the longest unbroken stretch of finished DNA sequence known so far. The chromosome is remarkable in having the lowest rate of segmental duplication in the genome. It also includes a chemokine receptor gene cluster as well as numerous loci involved in multiple human cancers such as the gene encoding FHIT, which contains the most common constitutive fragile site in the genome, FRA3B. Using genomic sequence from chimpanzee and rhesus macaque, we were able to characterize the breakpoints defining a large pericentric inversion that occurred some time after the split of Homininae from Ponginae, and propose an evolutionary history of the inversion. 相似文献