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151.
152.
A method is described for determining the relationship between primary production and respiration (P/R) in rapidly flowing waters. The Bliznec, Medveak and ernomerec Brooks near Zagreb-Jugoslavia, were taken as examples. The method evolved is based on the determination of oxygen at equally spaced time intervals during day and night (Table 1).Finally the formula % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0dh9WrFfpC0xh9vqqj-hEeeu0xXdbba9frFj0-OqFf% ea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs0dXdbPYxe9vr0-vr% 0-vqpWqaaeaabaGaciaacaqabeaadaqaaqaaaOqaamaalaaabaGaai% ikaiaadseadaWgaaWcbaGaaGOmaaqabaGccqGHsislcaWGebWaaSba% aSqaaiaaigdaaeqaaOGaaiykaiabgUcaRiaacIcacaWGobWaaSbaaS% qaaiaaigdaaeqaaOGaeyOeI0IaamOtamaaBaaaleaacaaIYaaabeaa% kiaacMcacqGHRaWkcaGGOaGaeuiLdqKaamizaiabgkHiTiabfs5aej% aad6gacaGGPaaabaGaamOtamaaBaaaleaacaaIXaaabeaakiabgkHi% Tiaad6eadaWgaaWcbaGaaGOmaaqabaGccqGHsislcqqHuoarcaWGUb% aaaaaa!5366!\[\frac{{(D_2 - D_1 ) + (N_1 - N_2 ) + (\Delta d - \Delta n)}}{{N_1 - N_2 - \Delta n}}\]% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0dh9WrFfpC0xh9vqqj-hEeeu0xXdbba9frFj0-OqFf% ea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs0dXdbPYxe9vr0-vr% 0-vqpWqaaeaabaGaciaacaqabeaadaqaaqaaaOqaaiaadcfacaGGVa% GaamOuaiabg2da9aaa!3AC3!\[P/R = \].is mentioned, where D1 denotes the average oxygen amount measured in the morning at the onset of the photosynthetic activity, D2 the average oxygen amount at the end of the photosynthetic activity, N1 the average oxygen deficiency at the beginning and at the end of dark period.For the purpose of checking, the values of saprobity determined after Zelinka & Marvan's method in a direct ecological way, in the same brook sections, are compared with the P/R values obtained (Table 2).Institute for Botany, University of Zagreb 相似文献
153.
Slađana Todorović Zlatko Giba Goran Bačić Miroslav Nikolic Dragoljub Grubišić 《Environmental and Experimental Botany》2008,64(3):322-324
The effect of high Mn2+ content on Centaurium pulchellum seed germination has been investigated. Seeds containing extremely high Mn2+ content were produced by culturing single-node flowering explants for 2 months in the MS-media, supplemented with Mn in concentrations ranging from 1 to 10,000 μM. Although the seeds displayed the capacity to accumulate high amount of Mn, their germination was undisturbed. EPR spectroscopy was used to measure the ratio of free (aqueous) Mn to bound Mn and it was found that over 97% of total Mn was in the bound form. With elevating the external Mn supply, seed Mn concentration also increased, but the proportion of free Mn2+ fraction decreased from 3% in the control (1 μM Mn) to 0.35% and 0.15% in high Mn supply (1000 μM and 10,000 μM, respectively). These results suggest that an elevation of internal Mn concentration in seeds is associated with increased Mn binding pools, hence Mn remains bound during germination. Consequently, the action of potentially harmful Mn2+ ions, which may generate ROS and affect seed viability, is alleviated. 相似文献
154.
Adams DH Strudwick XL Kopecki Z Hooper-Jones JA Matthaei KI Campbell HD Powell BC Cowin AJ 《The international journal of biochemistry & cell biology》2008,40(8):1555-1569
Impaired wound healing in the elderly presents a major clinical challenge. Understanding the cellular mechanisms behind age-related impaired healing is vital for developing new wound therapies. Here we show that the actin-remodelling protein, Flightless I (FliI) is a contributing factor to the poor healing observed in elderly skin and that gender plays a major role in this process. Using young and aged, wild-type and FliI overexpressing mice we found that aging significantly elevated FliI expression in the epidermis and wound matrix. Aging exacerbated the negative effect of FliI on wound repair and wounds in aged FliI transgenic mice were larger with delayed reepithelialisation. When the effect of gender was further analysed, despite increased FliI expression in young and aged male and female mice, female FliI transgenic mice had the most severe wound healing phenotype suggesting that male mice were refractory to FliI gene expression. Of potential importance, males, but not females, up-regulated transforming growth factor-β1 and this was most pronounced in aged male FliI overexpressing wounds. As FliI also functions as a co-activator of the estrogen nuclear receptor, increasing concentrations of β-estradiol were added to skin fibroblasts and keratinocytes and significantly enhanced FliI expression and translocation of FliI from the cytoplasm to the nucleus was observed. FliI further inhibited estrogen-mediated collagen I secretion suggesting a mechanism via which FliI may directly affect provisional matrix synthesis. In summary, FliI is a contributing factor to impaired healing and strategies aimed at decreasing FliI levels in elderly skin may improve wound repair. 相似文献
155.
This study contributes to the growing research on everyday cosmopolitanism in diverse societies. We employ a cosmopolitan encounters framework to explore the reflexive openness people perform and the ethical reasoning they draw on to get along with each other. In particular, we look beyond pleasurable cosmopolitan pursuits to consider encounters that cause frictions or require notable efforts to bridge differences as an occasion for cosmopolitan conviviality. Based on qualitative interviews conducted in Australia, we aim to sharpen the demarcation between cosmopolitan encounters and those in which diversity is strategically negotiated by enacting practices of civility. We argue that cosmopolitanism emerges from interactions in encounters between individuals when they reflect on their positionality within unequal power relationships and their actions are guided by a cosmopolitan ethics. The ethical framework we propose is grounded in reflexive acts of sharing going beyond notions of giving and performing hospitality within a host/guest dyad. 相似文献
156.
Ovarian cancer identification based on dimensionality reduction for high-throughput mass spectrometry data 总被引:9,自引:0,他引:9
Yu JS Ongarello S Fiedler R Chen XW Toffolo G Cobelli C Trajanoski Z 《Bioinformatics (Oxford, England)》2005,21(10):2200-2209
MOTIVATION: High-throughput and high-resolution mass spectrometry instruments are increasingly used for disease classification and therapeutic guidance. However, the analysis of immense amount of data poses considerable challenges. We have therefore developed a novel method for dimensionality reduction and tested on a published ovarian high-resolution SELDI-TOF dataset. RESULTS: We have developed a four-step strategy for data preprocessing based on: (1) binning, (2) Kolmogorov-Smirnov test, (3) restriction of coefficient of variation and (4) wavelet analysis. Subsequently, support vector machines were used for classification. The developed method achieves an average sensitivity of 97.38% (sd = 0.0125) and an average specificity of 93.30% (sd = 0.0174) in 1000 independent k-fold cross-validations, where k = 2, ..., 10. AVAILABILITY: The software is available for academic and non-commercial institutions. 相似文献
157.
158.
To assess local differentiation in host preference, a two-choice test was performed on first-instar gypsy moth larvae originating from an oak and locust-tree forest. More than 40 generations feeding on locust-tree leaves, rich in alkaloids, led to non-efficient discrimination of host leaves in larvae from a locust-tree forest. Possible causes of observed population differences are discussed in the present paper. 相似文献
159.
Regittnig W Ellmerer M Fauler G Sendlhofer G Trajanoski Z Leis HJ Schaupp L Wach P Pieber TR 《American journal of physiology. Endocrinology and metabolism》2003,285(2):E241-E251
We studied the kinetics of glucose exchange between plasma and interstitial fluid (ISF) in human skeletal muscle and adipose tissue under fasting conditions. Five normal human subjects received an intravenous [6,6-2H2]glucose infusion in a prime-continuous fashion. During the tracer infusion, the open-flow microperfusion technique was employed to frequently sample ISF from quadriceps muscle and subcutaneous adipose tissue. The tracer glucose kinetics observed in muscle and adipose tissue ISF were found to be well described by a capillary-tissue exchange model. As a measure of transcapillary glucose exchange efficiency, the 95% equilibrium time was calculated from the identified model parameters. This time constant was similar for skeletal muscle and adipose tissue (28.6 +/- 3.2 vs. 26.8 +/- 3.6 min; P = 0.60). Furthermore, we found that the (total) interstitial glucose concentration was significantly lower (P < 0.01) in muscle (3.32 +/- 0.46 mmol/l) and adipose tissue (3.51 +/- 0.17 mmol/l) compared with arterialized plasma levels (5.56 +/- 0.13 mmol/l). Thus the observed gradients and dynamic relationships between plasma and ISF glucose in muscle and adipose tissue provide evidence that transcapillary exchange of glucose is limited in these two tissues under fasting conditions. 相似文献
160.
Immunotherapy in multiple myeloma: Id-specific strategies suggested by studies in animal models 总被引:4,自引:2,他引:2
Corthay A Lundin KU Munthe LA Frøyland M Gedde-Dahl T Dembic Z Bogen B 《Cancer immunology, immunotherapy : CII》2004,53(9):759-769
Multiple myeloma (MM) cells produce monoclonal immunoglobulin (Ig) which serves as a truly tumor-specific antigen. The tumor-specific antigenic determinants are localized in the variable (V)-regions of the monoclonal Ig and are called idiotopes (Id). We review here the evidence obtained in a T-cell receptor (TCR) transgenic mouse model that Id-specific, MHC class II–restricted CD4+ T cells play a pivotal role in immunosurveillance and eradication of MHC class II-negative MM cells. In brief, monoclonal Ig secreted by MM cells is endocytosed and processed by antigen-presenting cells (APCs) in the tumor. Such tumor-resident dendritic cell APCs in turn present Id peptide on their class II molecules to Id-specific CD4+ T cells which become activated and indirectly kill the MHC class II-negative myeloma cells. However, if the Id-specific CD4+ cells fail to eliminate the MM cells during their initial encounter, the increasing number of tumor cells secretes so much monoclonal Ig that T-cell tolerance to Id is induced. Extending these findings to MM patients, Id-specific immunotherapy should be applied at a time of minimal residual disease and when new Id-specific T cells have been educated in the thymus, like after high-dose chemotherapy and autologous stem cell transplantation.Abbreviations APC antigen-presenting cell - ASCT autologous stem cell transplantation - CDR complementarity-determining region - CFA complete Freunds adjuvant - DC dendritic cell - GM-CSF granulocyte-macrophage colony-stimulating factor - H heavy - Id idiotope or idiotype - Ig immunoglobulin - IL interleukin - L light - M-component monoclonal component - MGUS monoclonal gammopathy of undetermined significance - MHC major histocompatibility complex - MM multiple myeloma - MOPC mineral oil–induced plasmacytoma - TCR T-cell antigen receptor - V variableA. Corthay and B. Bogen are joint corresponding authors for this article. 相似文献