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1.
Water Resources Management - This paper aims to evaluate the possibility of using non-utilized hydraulic energy in urban water distribution systems. For this purpose, the viability and possible...  相似文献   
2.
Recent research has found that family caregivers do not discuss their caregiving in terms of tasks but instead describe their care as shaped by concerns, commitments and goals. The purpose of this paper is to challenge the ways in which nurses approach the family caregiving process and to explore possibilities for evolving nursing knowledge by questioning existing practice in the light of developing insight into the ways in which being a family caregiver is meaningful. A critique of the philosophical orientations of rationalism and empiricism provides a platform to discuss the merits of a Heideggerian phenomenological approach in assisting nurses to better understand family caring experience. Such critique serves to support the notion of displacing the traditional scientific view as the prime means of disclosing truth, acknowledging alternative ways of knowing.  相似文献   
3.
Economic ideas and processes are becoming increasingly integrated with more traditional engineering and hydrologic models of water management problems. Combining economic management concepts and performance indicators with an engineering-level of understanding of a hydrologic system can provide results and insights more directly relevant for water management decisions and policies. When such models are developed and used with involvement of stakeholders, they can become a basis for shared understanding of water problems as a foundation for negotiated management and policy solutions. When implemented with optimization software, integrated hydro-economic models also can suggest promising innovative solutions for policy-makers to consider. Their applications to river basin management problems are reviewed. Economic and integrated economic-engineering-hydrologic modeling is then discussed in the context of the evolving European Water Framework Directive. Relevant items are cost recovery and water pricing, cost-effectiveness of water management measures, and public participation in decision processes.  相似文献   
4.
This paper explores current applications for handheld devices and questions which of these make full use of the unique attributes of handheld devices in order to facilitate learning in a pedagogically sensible manner. In order to do so, the paper presents a functional framework which analyses handheld application in relation to their use as well as the pedagogical underpinning, if any, that informs their development. Our framework currently consists of seven distinct categories of application, which we term: administrative, referential, interactive, microworld, data collection, location aware and collaborative. We argue that three categories, namely data collection, location aware and collaborative, are particularly suited to learning with handheld devices when they are informed by collaborative, contextual and constructionist learning theories. Furthermore, we contend that applications of the type just outlined deserve further research since they are not attempting to replicate, or even augment, existing learning scenarios but rather they try to create new learning opportunities which would not be possible without (mobile) technology. Finally, the authors introduce a number of applications and learning scenarios that they have developed for handheld devices and explain their position within the framework.  相似文献   
5.
The expression of p16 is a good surrogate of human papillomavirus (HPV) infection in HPV-associated cancers. The significance of p16 expression, HPV genotype and genera in the outcome of patients with HPV-associated cervical cancer (CC) is unclear. Our aim is to ascertain the prognostic significance of these factors. Data from 348 patients (median age: 47.5 years old) with CC, diagnosed in two referral centers, were retrospectively collected. Advanced disease (FIGO2018 IB2-IV) was present in 68% of patients. A single HPV genotype was identified in 82.8% of patients. The most common HPVs were HPV16 (69%) and HPV18 (14%). HPV genera reflected this distribution. HPV16 tumors presented at an earlier stage. P16 was negative in 18 cases (5.2%), 83.3% of which were squamous cell carcinomas. These cases occurred in older patients who tended to have advanced disease. In the univariate analysis, HPV16 (HR: 0.58; p = 0.0198), α-9 genera (HR: 0.37; p = 0.0106) and p16 overexpression (HR: 0.54; p = 0.032) were associated with better survival. HPV16 (HR: 0.63; p = 0.0174) and α-9 genera (HR: 0.57; p = 0.0286) were associated with less relapse. In the multivariate analysis, only the International Federation of Gynecology and Obstetrics (FIGO) stage retained an independent prognostic value. HPV16, α-9 genera and p16 overexpression were associated with better survival, although not as independent prognostic factors. Patients with p16-negative HPV-associated CC were older, presented with advanced disease and had worse prognosis.  相似文献   
6.
7.
The temperature dependence of both the permeability and diffusion coefficients of carbon dioxide, oxygen and nitrogen in annealed LLDPE films are studied. It is found that the values of the permeability coefficient through the annealed membranes are nearly four times larger than those through the non-annealed ones. The fact that annealing slightly diminishes the values of the diffusion coefficient leads to the conclusion that the rise in permeability detected in the films by effect of annealing should be attributed to an increase in solubility. The permeability characteristics of the films are interpreted in terms of the free volume theory.  相似文献   
8.
Pseudoxanthoma elasticum (PXE) is a genetic disorder associated to mutations in the ABCC6 gene; however, the pathogenetic mechanisms leading to elastic fibre calcifications and to clinical manifestations are still unknown. Dermal fibroblasts, directly involved in the production of the extracellular milieu, have been isolated from healthy subjects and from patients affected by PXE, cultured in vitro and characterized for their ability to produce reactive oxygen species, for structural and functional properties of their cell membranes, for changes in their protein profile. Data demonstrate that oxidative stress has profound and endurable consequences on PXE fibroblast phenotype being responsible for: reduced levels of global DNA methylation, increased amount of carbonylated proteins and of lipid peroxidation products, altered structural properties of cell membranes, modified protein expression. Data shed new light on the pathogenetic pathways in PXE, by identifying a network of proteins affecting elastic fibre calcification through inefficient vitamin K recycling, and highlight the role of differentially expressed proteins as targets for validating the efficacy of future therapeutic strategies aiming to delay and/or revert the pathologic phenotype of PXE fibroblasts. Moreover, data open new perspectives for investigating PXE-like phenotypes in the absence of ABCC6 mutations.  相似文献   
9.
Very few studies on recycled aggregate concretes (RC) have been extended to the use of recycled ceramic and mixed aggregates in relation with high strength concretes. In the main they concentrate only on the analysis of the physical and mechanical properties. This study deals with the investigation of the influence that different percentages (up to 30% substitution for natural aggregates) of high porous ceramic and mixed recycled aggregates have over the plastic, autogenous and drying shrinkage of the concretes. The physical and mechanical properties as well as the chloride resistance were also determine in order to assess the viability of the use of ceramic and mixed recycled aggregates in high strength concretes. The results revealed that the employment of highly porous recycled aggregates reduced the plastic and autogenous shrinkage values of the concrete with respect to those obtained by conventional concrete (CC). Although the total drying shrinkage of the recycled concrete proved to be 25% higher than that of the CC concrete, the CC concrete had in fact a higher shrinkage value than that of the RC from 7 to 150 days of drying. It can be concluded that the RC concrete produced employing up to 30% of fine ceramic aggregates (FCA, with 12% of absorption capacity) achieved the lowest shrinkage values and higher mechanical and chloride ion resistance. In addition, the concrete produced with low percentage (10–15%) of recycled mixed aggregates also had similar properties to conventional concrete.  相似文献   
10.
NSC 613862 (S)-(-) and NSC 613863 (R)-(+) are the two chiral isomers of ethyl-5-amino-2-methyl-1,2-dihydro-3-phenylpyrido[3, 4-b]pyrazin-7-yl carbamate. Both compounds bind to tubulin in a region that overlaps the colchicine site. They induce formation of abnormal polymers from purified GTP-Mg-tubulin, the active assembly form of tubulin, in glycerol-free buffer with magnesium [De Ines, C., Leynadier, D., Barasoain, I., Peyrot, V., Garcia, P., Briand, C., Rener, G. A., and Temple, C., Jr. (1994) Cancer Res. 54, 75-84]. In this study, we observed that the S-isomer can promote polymerization of GDP-tubulin, the inactive assembly-incompetent form of tubulin, into nonmicrotubular structures at a critical protein concentration of 1 mg/mL (12 mM MgCl2). Neither the R-isomer nor colchicine have this ability. By electron microscopy, these tubulin polymers showed the same poorly defined filamentous structure when GDP-tubulin or GTP-Mg-tubulin were used. By HPLC measurements, we demonstrated that a dissociated GTP hydrolysis and exchange of nucleotide occurred during the isomer-induced abnormal assembly. Both isomers inhibited the Mg2+-induced tubulin self-association leading to 42 S double ring formation from GTP-Mg-tubulin or GDP-tubulin. Measurement of their binding under nonassociation conditions revealed a 3-fold decrease in the apparent equilibrium binding constant of the R-isomer to GDP-tubulin relative to GTP-Mg-tubulin. For the S-isomer, the decrease in the binding constant was less pronounced. Binding data, analyzed in terms of a system of linked conformational and association equilibria, provide evidence that the active ("straight") rather than the inactive ("curved") conformation of tubulin differentially recognizes these ligands. Whereas binding of colchicine to tubulin is well-known to induce GTP hydrolysis, this is the first case in which the interaction of a ligand with the colchicine site is shown to be sensitive to the presence of GDP or GTP at the distant nucleotide binding site.  相似文献   
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