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1.
Azaperone alone and combined with ketamine were evaluated as sedative and anesthetic agents in outbred rats and mice. Using azaperone alone the duration of immobility was 1.9 to 10.8 hours for mice and 0.9 to 2.4 hours for rats. The withdrawal reflex was not eliminated from mice receiving azaperone alone; however, the withdrawal reflex was eliminated from 0.9 to 2.4 hours in rats receiving azaperone. Azaperone produced a tachypnea in rats and male mice while a depressed respiratory rate was observed in female mice. Using azaperone combined with ketamine, the duration of immobilization was 1.1 to 8.8 hours for mice and 1.3 to 6.0 hours for rats. The duration loss of the withdrawal reflex, which was used as an indication of surgical anesthesia, was 0.9 to 1.8 hours for mice and 1.0 to 6.0 hours for rats. An increase in respiratory rate was observed in rats given the combination while mice given the combination showed transient tachypnea followed by bradypnea. Overall, azaperone alone was shown to provide sedation in mice as compared to a dose dependent anesthesia in rats. The azaperone-ketamine combination produced a surgical plane of anesthesia in both rats and mice. Azaperone and the azaperone-ketamine combination appear to be a suitable alternative to sedatives and anesthetics currently used in rats and mice. 相似文献
2.
Soil and wastewater treatment sludge are commonly brought together in mixtures for a variety of beneficial purposes. The mixtures contain bioacidifying (i.e., sulfur-oxidizing) microorganisms that can easily be activated through providing the appropriate substrate and environmental conditions. In this study, contaminated soil and sludge mixtures were subjected to controlled bio-acidification and the impacts of the process on the partitioning of heavy metals, nitrogen, and phosphorus were examined. Three successive bio-acidification cycles resulted in significant leaching of metals from sludge. The leaching results, expressed as fraction of total mass of metals in the sludge, averaged 67% for Cr, 96% for Ni, 24% for Zn; 16% for Cu; 23% for Cd; and 96% for Pb. Bio-acidification of the sludge also converted 28 to 45% of the organic nitrogen into ammonia and increased the soluble orthophosphates fraction of total phosphorus by approximately 18 to 20%. Bio-acidification also resulted in significant metals leaching from the contaminated soils in the soil/sludge mixtures. Soil/sludge mixtures were prepared using six soil particle sizes (less than 0.075?mm to 2.38?mm) contaminated with 22,500?mg/kg Zn, 14,000?mg/kg Pb, 1500?mg/kg Cr, 9500?mg/kg Cu, 1000?mg/kg Ni, and 1000?mg/kg Cd. The addition of metals to the soil inhibited the sulfur-oxidizing microorganisms, preventing bio-acidification in the mixtures containing 4 to 50?g soil in 130?ml sludge, and considerably slowing bio-acidification in the mixtures containing 1 to 3?g soil. Using a mixture that contained 2-g soil samples, three successive bio-acidification cycles resulted in significant cumulative metals leaching results. The leaching results, expressed as percentage of the mass of metals added to the soil, were in the range of 56 to 98% for Cr, 77 to 95% for Zn, 33 to 66% for Ni, 64 to 82% for Cu, and 10 to 33% for Pb, with the higher results in each range belonging to the larger size soil particles. On the other hand, only Cr was leached in neutralized soil samples. The results confirmed the potential for inhibition of the sulfur-oxidizing microorganisms and bio-acidification in contaminated soil/sludge mixtures, and the significant impacts of bio-acidification on the mobility of metals, nitrogen, and phosphorus. In addition, the results confirmed the potential for using controlled bioacidification for removing heavy metals from contaminated soil using the indigenous sulfur oxidizing microorganisms in sludge. 相似文献
3.
生物多样性与生态系统服务——关系、权衡与管理 总被引:4,自引:0,他引:4
生物多样性和生态系统服务是人类生存和社会经济可持续发展的物质基础,应对生物多样性丧失和生态系统服务退化问题已经成为继气候变化之后的又一个全球性环境热点问题。生物多样性是生态系统生产力、稳定性、抵抗生物入侵以及养分动态的主要决定因素,生物多样性越高,生态系统功能性状的范围越广,生态系统服务质量就越高越稳定。目的是探讨生物多样性和生态系统服务之间的关系:(1)明确了生物多样性与生态系统过程、功能、服务之间的关系;(2)生物多样性在生态系统服务中的角色:生物多样性在不同的空间尺度通过各种形式的运行机制与生态系统服务产生联系,生物多样性是生态系统过程的调节者,是巩固生态系统服务的一个重要因素,生物多样性也是一种终极的生态系统服务,并在遗传和物种水平上直接贡献了其利益和价值;(3)生物多样性与生态系统服务权衡和协同关系的研究可以更好的帮助管理人员做出有利的决策和保护工作,也是制定规划和适应策略以减少生物多样性危机带来的不利影响的基础;(4)生物多样性与生态系统服务的关系在不同的时间和空间尺度上是不恒定的,有必要共同确定生态系统服务和生物多样性的空间格局,以有效和可持续的进行生态系统管理;(5)虽然生物多样性保护和生态系统管理还存在许多不确定性,但相关理论应该在管理、保护和恢复生态系统中发挥重要作用。研究提出了进一步研究的领域,以促进生物多样性保护和生态系统服务提供之间的协同作用。希望对相关领域的研究有所帮助。 相似文献
4.
5.
The available power tables for use in experimental design only serve for limited practical purposes, since they are restricted to very few levels of significance such as .01, .05, and .10. With these values, however, usually no correction for cumulating error probabilities, for example, by the Dunn-Bonferroni method, can be achieved, because (very) low values of a and sometimes even of α are necessary. Therefore, power tables are presented that encompass a wide range of different values for a (.0005 to .40), for power (.50 to .9995), and for 45 different values of the degrees of freedom for the numerator of the F ratio (u = 1 to 150). Four of the 16 tables are printed. Their use is demonstrated for some paradigmatic problems in univariate and multivariate analyses of variance and regression. 相似文献
6.
J Szymas 《Analytical cellular pathology》2000,21(3-4):183-191
Our experience in creating and using telepathology system and multimedia database for education is described. This program packet currently works in the Department of Pathology of University Medical School in Poznan. It is used for self-education, tests, services and for the examinations in pathology, i.e., for dental students and for medical students in terms of self-education and individual examination services. The system is implemented on microcomputers compatible with IBM PC and works in the network system Netware 5.1. Some modules are available through the Internet. The program packet described here accomplishes the TELEMIC system for telepathology, ASSISTANT, which is the administrator for the databases, and EXAMINATOR, which is the executive program. The realization of multi-user module allows students to work on several working areas, on random be chosen different sets of problems contemporary. The possibility to work in the exercise mode will image files and questions is an attractive way for self-education. The standard format of the notation files enables to elaborate the results by commercial statistic packets in order to estimate the scale of answers and to find correlation between the obtained results. The method of multi-criterion grading excludes unlimited mutual compensation of the criteria, differentiates the importance of particular courses and introduces the quality criteria. The packet is part of the integrated management information system of the department of pathology. Applications for other telepathological systems are presented. 相似文献
7.
Cobalt and antimony: genotoxicity and carcinogenicity 总被引:6,自引:0,他引:6
The purpose of this review is to summarise the data concerning genotoxicity and carcinogenicity of Co and Sb. Both metals have multiple industrial and/or therapeutical applications, depending on the considered species. Cobalt is used for the production of alloys and hard metal (cemented carbide), diamond polishing, drying agents, pigments and catalysts. Occupational exposure to cobalt may result in adverse health effects in different organs or tissues. Antimony trioxide is primarily used as a flame retardant in rubber, plastics, pigments, adhesives, textiles, and paper. Antimony potassium tartrate has been used worldwide as an anti-shistosomal drug. Pentavalent antimony compounds have been used for the treatment of leishmaniasis. Co(II) ions are genotoxic in vitro and in vivo, and carcinogenic in rodents. Co metal is genotoxic in vitro. Hard metal dust, of which occupational exposure is linked to an increased lung cancer risk, is proven to be genotoxic in vitro and in vivo. Possibly, production of active oxygen species and/or DNA repair inhibition are mechanisms involved. Given the recently provided proof for in vitro and in vivo genotoxic potential of hard metal dust, the mechanistic evidence of elevated production of active oxygen species and the epidemiological data on increased cancer risk, it may be advisable to consider the possibility of a new evaluation by IARC. Both trivalent and pentavalent antimony compounds are generally negative in non-mammalian genotoxicity tests, while mammalian test systems usually give positive results for Sb(III) and negative results for Sb(V) compounds. Assessment of the in vivo potential of Sb2O3 to induce chromosome aberrations (CA) gave conflicting results. Animal carcinogenicity data were concluded sufficient for Sb2O3 by IARC. Human carcinogenicity data is difficult to evaluate given the frequent co-exposure to arsenic. Possible mechanisms of action, including potential to produce active oxygen species and to interfere with DNA repair systems, still need further investigation. 相似文献
8.
Astrocytes transport the monocarboxylate acetate, but synaptosomes do not. The reason for this is unknown, because both preparations express monocarboxylate transporters (MCT). The transport and metabolism of lactate, another monocarboxylate, was examined in these two preparations, and the results were compared to those for acetate. Lactate transport is more rapid in astrocytes than in synaptosomes, but of lower affinity (Kms of 17 and 4 mM, respectively). Lactate (0.2 mM) is metabolized to CO2 more rapidly in synaptosomes than in astrocytes (rates of 0.37 and 0.07 nmol x mg protein(-1) x min(-1), respectively). The reason for this is unclear, but cellular differences in lactate dehydrogenase isotype expression may be involved. Acetate is metabolized to CO2 more rapidly in astrocytes than in synaptosomes (rates of 0.43 and 0.02 nmol x mg protein(-1) x min(-1), respectively). This is likely due to cellular differences in the expression of monocarboxylate transporter subtypes. 相似文献
9.
Handler AM 《Insect biochemistry and molecular biology》2004,34(2):121-130
Genetically transformed insect pests provide significant opportunities to create strains for improved sterile insect technique and new strategies based on conditional lethality. A major concern for programs that rely on the release of transgenic insects is the stability of the transgene, and maintenance of consistent expression of genes of interest within the transgene. Transgene instability would influence the integrity of the transformant strain upon which the effectiveness of the biological control program depends. Loss or intra-genomic transgene movement would result in strain attributes important to the program being lost or diminished, and the mass-release of such insects could significantly exacerbate the insect pest problem. Instability resulting in intra-genomic movement may also be a prelude to inter-genomic transgene movement between species resulting in ecological risks. This is less of a concern for short-term releases, where transgenic insects are not expected to survive in the environment beyond two or three generations. Transgene movement may occur, however, into infectious agents during mass-rearing, and the potential for movement after release is a possibility for programs using many millions of insects. The primary methods of addressing potential transgene instability relate to an understanding of the vector system used for gene transfer, the potential for its mobilization by the same or a related vector system, and methods required to identify transformants and determine if unexpected transgene movement has occurred. Methods also exist for preventing transposon-mediated mobilization, by deleting or rearranging vector sequences required for transposition using recombination systems. Stability of transgene expression is also a critical concern, especially in terms of potential epigenetic interactions with host genomes resulting in gene silencing that have been observed in plants and fungi, and it must be determined if this or related phenomena can occur in insects. 相似文献
10.
Cruz-Neto AP Andrade DV Abe AS 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2001,128(3):515-533
In this review, we summarize the energetic and physiological correlates of prey handling and ingestion in lizards and snakes. There were marked differences in the magnitude of aerobic metabolism during prey handling and ingestion between these two groups, although they show a similar pattern of variation as a function of relative prey mass. For lizards, the magnitude of aerobic metabolism during prey handling and ingestion also varied as a function of morphological specializations for a particular habitat, prey type, and behavior. For snakes, interspecific differences in aerobic metabolism during prey handling seem to be correlated with adaptations for prey capture (venom injection vs. constriction). During ingestion by snakes, differences in aerobic metabolism might be due to differences in cranial morphology, although allometric effects might be a potentially confounded effect. Anaerobic metabolism is used for prey handling and ingestion, but its relative contribution to total ATP production seems to be more pronounced in snakes than in lizards. The energetic costs of prey handling and ingestion are trivial for both groups and cannot be used to predict patterns of prey-size selection. For lizards, it seems that morphological and ecological factors set the constraints on prey handling and ingestion. For snakes, besides these two factors, the capacity of the cardio-respiratory system may also be an important factor constraining the capacity for prey handling and ingestion. 相似文献
11.
Glucose is widely accepted as the primary nutrient for maintenance and promotion of cell function. However, we propose that the 5-carbon amino acids, glutamine and glutamate, should be considered to be equally important for maintenance and promotion of cell function. The functions of glutamine are many and include: substrate for protein synthesis, anabolic precursor for muscle growth, acid-base balance in the kidney, substrate for ureogenesis in the liver, substrate for hepatic and renal gluconeogenesis, an oxidative fuel for intestine and cells of the immune system, inter-organ nitrogen transport, precursor for neurotransmitter synthesis, precursor for nucleotide and nucleic acid synthesis and precursor for glutathione production. Many of these functions are connected to the formation of glutamate from glutamine. We propose that the unique properties regarding concentration and routes of metabolism of these amino acids allow them to be used for a diverse array of processes related to the specialized function of each of the glutamine utilizing cells. In this review we highlight the specialized aspects of glutamine/glutamate metabolism of different glutamine-utilizing cells and in each case relate key aspects of metabolism to cell function. 相似文献
12.
The use of nanotechnology in medicine and more specifically drug delivery is set to spread rapidly. Currently many substances are under investigation for drug delivery and more specifically for cancer therapy. Interestingly pharmaceutical sciences are using nanoparticles to reduce toxicity and side effects of drugs and up to recently did not realize that carrier systems themselves may impose risks to the patient. The kind of hazards that are introduced by using nanoparticles for drug delivery are beyond that posed by conventional hazards imposed by chemicals in classical delivery matrices. For nanoparticles the knowledge on particle toxicity as obtained in inhalation toxicity shows the way how to investigate the potential hazards of nanoparticles. The toxicology of particulate matter differs from toxicology of substances as the composing chemical(s) may or may not be soluble in biological matrices, thus influencing greatly the potential exposure of various internal organs. This may vary from a rather high local exposure in the lungs and a low or neglectable exposure for other organ systems after inhalation. However, absorbed species may also influence the potential toxicity of the inhaled particles. For nanoparticles the situation is different as their size opens the potential for crossing the various biological barriers within the body. From a positive viewpoint, especially the potential to cross the blood brain barrier may open new ways for drug delivery into the brain. In addition, the nanosize also allows for access into the cell and various cellular compartments including the nucleus. A multitude of substances are currently under investigation for the preparation of nanoparticles for drug delivery, varying from biological substances like albumin, gelatine and phospholipids for liposomes, and more substances of a chemical nature like various polymers and solid metal containing nanoparticles. It is obvious that the potential interaction with tissues and cells, and the potential toxicity, greatly depends on the actual composition of the nanoparticle formulation. This paper provides an overview on some of the currently used systems for drug delivery. Besides the potential beneficial use also attention is drawn to the questions how we should proceed with the safety evaluation of the nanoparticle formulations for drug delivery. For such testing the lessons learned from particle toxicity as applied in inhalation toxicology may be of use. Although for pharmaceutical use the current requirements seem to be adequate to detect most of the adverse effects of nanoparticle formulations, it can not be expected that all aspects of nanoparticle toxicology will be detected. So, probably additional more specific testing would be needed. 相似文献
13.
D. C. Whitehead 《Plant and Soil》1987,97(1):47-56
Summary White clover and perennial ryegrass were grown separately, in pots maintained under controlled environment conditions, for a period of 7 months on ten soils. The proportion of the total soil content of each element taken up by the ryegrass, including that in roots, ranged from 0.88 to 2.18% for Cu, from 0.82 to 2.80% for Zn and from 0.25 to 3.15% for Mn. Uptake by the clover was within these ranges for Cu and Zn, but ranged from 0.10 to 1.71% for Mn.After adjustment for the effects of soil contamination, the ratio of root concentration: shoot concentration was always greater than 1 for both Cu and Zn, and for Cu, though not for Zn, it was considerably greater with ryegrass than with clover. For Mn, the ratio of root:shoot concentration was often greater than 1, and differences between clover and grass were not consistent.Concentrations of Cu and Zn in the shoots were always greater in the clover than in the grass, but concentrations of Mn were generally greater in the grass than the clover. 相似文献
14.
Selkoe DJ 《Current opinion in neurobiology》2000,10(1):50-57
Recent progress in elucidating the biology of Notch and presenilin has revealed a close functional relationship between these two proteins during cell fate determination in worms, flies and humans. Presenilins are required for the putatively intramembranous proteolysis of Notch to release its intracellular domain to the nucleus. This finding establishes a specific biochemical role for presenilins in Notch signaling and interfaces with emerging evidence about how frizzled, disheveled and numerous other genes regulate the highly complex Notch pathway. Advances in understanding Notch and presenilin functions in the differentiation of neurons and non-neural cells have important implications not only for development but also for late-life degenerative disorders such as Alzheimer's disease. 相似文献
15.
Norman P. Li April R. Smith Vladas Griskevicius Margaret J. Cason Angela Bryan 《Evolution and human behavior》2010,31(5):365-372
Restrictive eating attitudes and behaviors have been hypothesized to be related to processes of intrasexual competition. According to this perspective, within-sex competition for status serves the adaptive purpose of attracting mates. As such, status competition salience may lead to concerns of mating desirability. For heterosexual women and gay men, such concerns revolve around appearing youthful and, thus, thinner. Following this logic, we examined how exposure to high-status and competitive (but not thin or highly attractive) same-sex individuals would influence body image and eating attitudes in heterosexual and in gay/lesbian individuals. Results indicated that for heterosexuals, intrasexual competition cues led to greater body image dissatisfaction and more restrictive eating attitudes for women, but not for men. In contrast, for homosexual individuals, intrasexual competition cues led to worse body image and eating attitudes for gay men, but not for lesbian women. These findings support the idea that the ultimate explanation for eating disorders is related to intrasexual competition. 相似文献
16.
M Ali C J Gubler J Al Saleh F Abu Farsak 《Comparative biochemistry and physiology. B, Comparative biochemistry》1987,87(4):833-835
1. A study was made of transketolase activity in red and white blood cells and of conditions for assay for transketolase activity and for assessment of the "TPP effect" in human and rat blood. 2. The ratio of the transketolase activity in white cells to that in red cells varied between 23 and 93. 3. Red cells or white cells can both be used for assessment of transketolase activity and the "TPP effect", but the best source for evaluation of transketolase activity and the percent change on addition of thiamin diphosphate appears to be whole blood. 相似文献
17.
Conserving and managing biodiversity in the face of ongoing global change requires sufficient evidence to assess status and trends of species distributions. Here, we propose novel indicators of biodiversity data coverage and sampling effectiveness and analyze national trajectories in closing spatiotemporal knowledge gaps for terrestrial vertebrates (1950 to 2019). Despite a rapid rise in data coverage, particularly in the last 2 decades, strong geographic and taxonomic biases persist. For some taxa and regions, a tremendous growth in records failed to directly translate into newfound knowledge due to a sharp decline in sampling effectiveness. However, we found that a nation’s coverage was stronger for species for which it holds greater stewardship. As countries under the post-2020 Global Biodiversity Framework renew their commitments to an improved, rigorous biodiversity knowledge base, our findings highlight opportunities for international collaboration to close critical information gaps.Conserving and managing biodiversity in the face of ongoing global change requires sufficient evidence to assess status and trends of species distributions. This study analyzes national trajectories in closing spatiotemporal knowledge gaps for terrestrial vertebrates (1950-2019) based on novel indicators of data coverage and sampling effectiveness. 相似文献
18.
Luis A. Buatois M. Gabriela Mángano 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2013,46(3):281-292
Ichnodiversity has been used as a proxy for environmental stress and stability in facies interpretations and to reconstruct evolutionary radiations and colonization histories in evolutionary palaeoecology. The three components of global diversity are exported from ecology and adapted for ichnology. Alpha ichnodiversity is used for palaeoenvironmental characterization, being assessed for individual facies. Beta ichnodiversity is commonly overlooked, although it may provide information about degree of similarity between ichnofaunas formed along environmental gradients. Gamma ichnodiversity may provide clues to detect ichnofossil provincialism. The concept of disparity may also prove to be significant in ichnological studies. Whereas ichnodiversity refers to ichnotaxonomic richness, ichnodisparity provides a measure of the variability of morphological plans in biogenic structures. Changes in global ichnodiversity do not necessarily parallel changes in ichnodisparity. For example, while the Cambrian explosion involved a dramatic increase in both, the Ordovician radiation essentially reflects an increase only in the former. Ichnodiversity and ichnodisparity should be used with caution because they are both affected by taphonomic processes. High diversity of superficial to shallow‐tier trace fossils may result from enhanced preservation due a poorly developed mixed layer, rather than a true reflection of ecosystem performance, as shown by underexploited infaunal ecospace after biotic crises (e.g. end‐Permian mass extinction). 相似文献
19.
Dudley N Baldock D Nasi R Stolton S 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2005,360(1454):457-470
Most of the world's biodiversity will continue to exist outside protected areas and there are also managed lands within many protected areas. In the assessment of millennium targets, there is therefore a need for indicators to measure biodiversity and suitability of habitats for biodiversity both across the whole landscape/seascape and in specific managed habitats. The two predominant land uses in many inhabited areas are forestry and agriculture and these are examined. Many national-level criteria and indicator systems already exist that attempt to assess biodiversity in forests and the impacts of forest management, but there is generally less experience in measuring these values in agricultural landscapes. Existing systems are reviewed, both for their usefulness in providing indicators and to assess the extent to which they have been applied. This preliminary gap analysis is used in the development of a set of indicators suitable for measuring progress towards the conservation of biodiversity in managed forests and agriculture. The paper concludes with a draft set of indicators for discussion, with suggestions including proportion of land under sustainable management, amount of produce from such land, area of natural or high quality semi-natural land within landscapes under sustainable management and key indicator species. 相似文献
20.
This experiment investigated the effect of signal modality on time perception in 5- and 8-year-old children as well as young adults using a duration bisection task in which auditory and visual signals were presented in the same test session and shared common anchor durations. Durations were judged shorter for visual than for auditory signals by all age groups. However, the magnitude of this modality difference was larger in the children than in the adults. Sensitivity to time was also observed to increase with age for both modalities. Taken together, these two observations suggest that the greater modality effect on duration judgments for the children, for whom attentional abilities are considered limited, is the result of visual signals requiring more attentional resources than are needed for the processing of auditory signals. Within the framework of the information-processing model of Scalar Timing Theory, these effects are consistent with a developmental difference in the operation of the "attentional switch" used to transfer pulses from the pacemaker into the accumulator. Specifically, although timing is more automatic for auditory than visual signals in both children and young adults, children have greater difficulty in keeping the switch in the closed state during the timing of visual signals. 相似文献