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JINDŘIŠKA BOJKOVÁ KLÁRA KOMPRDOVÁ TOMÁŠ SOLDÁN SVĚTLANA ZAHRÁDKOVÁ 《Freshwater Biology》2012,57(12):2550-2567
1. Rapid expansion and intensification of anthropogenic activities in the 20th century has caused profound changes in freshwater assemblages. Unfortunately, knowledge of the extent and causes of species loss (SL) is limited due to the lack of reliable historical data. An unusual data set allows us to compare changes in the most sensitive of aquatic insect orders, the Plecoptera, at some 170 locations in the Czech Republic between two time periods, 1955–1960 and 2006–2010. Historical data (1890–1911) on assemblages of six lowland rivers allow us to infer even earlier changes. 2. Regional stonefly diversity decreased in the first half of the 20th century. Streams at lower altitudes lost a substantial number of species, which were never recovered. In the second half of the century, large‐scale anthropogenic pressure caused SL in all habitats, leading to a dissimilarity of contemporary and previous assemblages. The greatest changes were found at sites affected by organic pollution and a mixture of organic pollution and channelisation or impoundment. Colonisation of new habitats was observed in only three of the 80 species evaluated. 3. Species of moderate habitat specialisation and tolerance to organic pollution were most likely to be lost. Those with narrow specialisations in protected habitats were present in both historical and contemporary collections. 4. Contemporary assemblages are the consequence of more than a 100 years of anthropogenic impacts. In particular, streams at lower altitude and draining intensively exploited landscapes host a mere fragment of the original species complement. Most stonefly species are less frequently present than before, although their assemblages remain almost intact in near‐natural mountain streams. Our analyses demonstrate dramatic restriction of species ranges and, in some cases, apparent changes in altitudinal preference throughout the area. 相似文献
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目的:研究铼.188标记生物分子在肿瘤治疗中的应用。方法:选取小白鼠作为实验的研究对象,将荷瘤鼠的肉瘤切成小块接种到小白鼠身上,达到试验条件时使用,即将没有明显差异的小白鼠16只随机分为4组,每组4只,注射含有铼一188的药物后分别在不同的时间将其处死,之后取出重要器官进行测量分析,进而得出铼一188的应用效果。结果:瘤内注射的要去在不同时间放射性在瘤内的保持率分别为(90.5±7.7)D%(1h),(92.2±8.6)D%(24h),(88.3±10.9)D%(48h)和(91.5±7.6)D%(72h),在荷瘤鼠内注入生理盐水、非放硫化铼和188Re.硫化铼混悬液,肿瘤质量分别为2885.3±1241.3、2839.9±1965.2和98.4±45.5mg。188Re-硫化铼混悬液在生理盐水、磷酸盐缓冲液和小牛血清中均可稳定72h,而且188W-188Re发生器的应用还可以降低188Re-硫化铼混悬液的价格。随着处死时间的延迟,小鼠肿瘤质量和体积逐渐减小,相临两组比较,后组测定值均明显小于前组,数据经统计学比较具有显著差异(P〈0.05)。结论:188Re-硫化铼混悬液是一种适宜的肿瘤治疗剂。 相似文献
35.
Background
In August 2006 a major epidemic of bluetongue virus serotype 8 (BTV8) started off in North-West Europe. In the course of 2007 it became evident that BTV8 had survived the winter in North-West Europe, re-emerged and spread exponentially. Recently, the European Union decided to start vaccination against BTV8. In order to improve the understanding of the epidemiological situation, it was necessary to execute a cross-sectional serological study at the end of the BT vector season. Cattle were the target species for cross-sectional serological studies in Europe at the end of 2006 and 2007. However, there was no information on the BTV8-seroprevalence in sheep and goats. 相似文献36.
K. K. Bhandary T. D. Sakore Henry M. Sobell Dalton King Edword J. Gabbay 《Journal of biomolecular structure & dynamics》2013,31(5):1195-1217
Abstract This paper describes two complexes containing N,N-dimethylproflavine and the dinucleoside monophosphate, 5-iodocytidylyl(3′-5′)guanosine (iodoCpG). The first complex is triclinic, space group PI, with unit cell dimensions a = 11.78 Å, b = 14.55 Å, c = 15.50 Å, a = 89.2°, β = 86.2°, γ = 96.4°. The second complex is monoclinic, space group P21, with a = 14.20 Å, b = 19.00 Å, c = 20.73 Å, β = 103.6°. Both structures have been solved to atomic resolution and refined by Fourier and least squares methods. The first structure has been refined anisotropically to a residual of 0.09 on 5,025 observed reflections using block diagonal least squares, while the second structure has been refined isotropically to a residual of 0.13 on 2,888 reflections with full matrix least squares. The asymmetric unit in both structures contains two dimethylproflavine molecules and two iodoCpG molecules; the first structure has 16 water molecules (a total of 134 non-hydrogen atoms), while the second structure has 18 water molecules (a total of 136 non-hydrogen atoms). Both structures demonstrate intercalation of dimethylproflavine between base-paired iodoCpG dimers. In addition, dimethylproflavine molecules stack on either side of the intercalated duplex, being related by a unit cell translation along b and a axes, respectively. The basic structural feature of the sugar-phosphate chains accompanying dimethylproflavine intercalation in both structures is the mixed sugar puckering pattern: C3′ endo (3′-5′) C2′ endo. This same structural information is again demonstrated in the accompanying paper, which describes a complex containing dimethylproflavine with deoxyribo-CpG. Similar information has already appeared for other “simple” intercalators such as ethidium, acridine orange, ellipticine, 9-aminoacridine, N-methyl-tetramethylphenanthrolinium and terpyridine platinum. “Complex” intercalators, however, such as proflavine and daunomycin, have given different structural information in model studies. We discuss the possible reasons for these differences in this paper and in the accompanying paper. 相似文献
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Further identification of the nature and linkage of the carbohydrate in hemoglobin A1c. 总被引:24,自引:0,他引:24
H F Bunn D N Haney K H Gabbay P M Gallop 《Biochemical and biophysical research communications》1975,67(1):103-109
We have found that Hb A1c contains neutral sugars which are only partially hydrolyzed from the N-termini of β chains. In both normal and diabetic Hb A1c, 0.2–0.3 equivalents of hexose were released, composed primarily of glucose and mannose in a 3:1 ratio. When Hb A1c was reduced with 3HNa BH4 and then treated with periodic acid, most of the radioactivity was recovered as 3H-formic acid with much lesser amounts of 3H-formaldehyde. From these results, we propose that in the red cell, glucose binds to the α-amino position of hemoglobin β-chains (valine) in an aldimine (Schiff base) linkage. This aldimine can then partially rearrange in a reversible manner to form a ketoamine linkage which is stable to acid hydrolysis. This Amadori-type rearrangement accounts for the formation of mannose, the C-2 epimer of glucose, as well as the inability to demonstrate 3HNa BH4 reduction at the C-1 position. 相似文献
39.
Lucas R Lopes Vitor AR Miranda Rodrigo A Goes Gabriel GA Souza Giuliana R Souza Jessica CS Rocha Victor RA Cossich Jamila A Perini 《Biology of sport / Institute of Sport》2021,38(4):703
The COVID-19 pandemic has presented significant challenges and implications for the sports community. Thus, this study aimed to describe the prevalence of COVID-19 in Brazilian athletes and identify the epidemiological, clinical, athletic, life and health factors associated with the disease in these individuals. A cross-sectional study was performed involving 414 athletes from 22 different sports using an online questionnaire from August to November 2020. The association between the athletes’ characteristics and COVID-19 was evaluated using a logistic regression model. The prevalence of COVID-19 was 8.5%, although only 40% of athletes reported having been tested. Being under 27 years of age (3-fold), having children (~5-fold), having a teammate test positive for COVID-19 (2.5-fold), and smoking (14-fold) were associated with a possible higher risk of disease. Almost 20% of athletes self-reported musculoskeletal injuries during the period of the pandemic that was studied. Athletes with a university education (P = 0.02), a profession other than sports (P < 0.001), those from a low-income family (P = 0.01), and public health system users (P = 0.04) were significantly less frequently tested for COVID-19, whereas international competitors, athletes who received a wage, and athletes who had a teammate who tested positive for COVID-19 were 2-, 3-, and 15-fold more likely to be tested for COVID-19, respectively. Approximately 26% of the athletes who tested negative or were untested reported more than three characteristic COVID-19 symptoms, and 11% of athletes who tested positive for COVID-19 were asymptomatic. The identification of modifiable (have children, smoking, and teammates positively tested) and non-modifiable (age under 27 years) factors related to COVID-19 in athletes can contribute to implementing surveillance programmes to decrease the incidence of COVID-19 in athletes and its negative impacts in sports. 相似文献
40.
JF Yuan SJ Zhang O Jafer RA Furlong OE Chausiaux CA Sargent GH Zhang NA Affara 《BMC microbiology》2009,9(1):246