摘要 :
Agrotourism is an entrepreneurial initiative in the agricultural sector hampered by its uncertain legal status. The fact that agrotourism is an integrated investment associated with other activities, makes it a very attractive opt...
展开
Agrotourism is an entrepreneurial initiative in the agricultural sector hampered by its uncertain legal status. The fact that agrotourism is an integrated investment associated with other activities, makes it a very attractive option, especially inmarginal areas where tourism and agricultural activities are complementary and agrotourism may make a significant socioeconomic contribution to regional development. Growth in agrotourism is, however, heavily dependent on past and present development policies in individual regions. Although policies introduced after the CAP reform favour multi-functional establishments, in some areas old policies continue to hamper growth or limit the potential benefits. Other problems, such as training of personnel, finance and unregulated activities along with a lack of appropriate land development policies also have a negative effect on potential growth. A proposal for overcoming these problems is put forward.
收起
摘要 :
The paper deals with the photocatalytic transformation of two antibacterial agents, ofloxacin and ciprofloxacin, under simulated solar irradiation using titanium dioxide as photocatalyst. The investigation involved monitoring deco...
展开
The paper deals with the photocatalytic transformation of two antibacterial agents, ofloxacin and ciprofloxacin, under simulated solar irradiation using titanium dioxide as photocatalyst. The investigation involved monitoring decomposition of the drugs, identifying intermediate compounds, assessing mineralization, and evaluating the toxicity of drug derivatives. High-resolution mass spectrometry was employed to assess evolution of the photocatalyzed process over time. Respectively 15 and 8 main species were identified after transformation of ofloxacin and ciprofloxacin. Through the full analysis of MS and MS' spectra and a comparison with parent drug fragmentation pathways, the different isomers were characterized. In the ofloxacin molecule, the initial transformation attacks are confined to the piperazine moiety and to the methyl groups, while the fluoroquinolone core is unmodified. Conversely, ciprofloxacin degradation involves two parts of the molecule: the piper-azinic moiety and the quinolone moiety. All these intermediates are easily degraded and by 4h mineralization is complete. Toxicity assays using Vibrio fischeri prove that neither ciprofloxacin nor its intermediates exhibit acute toxicity. In ofloxacin the secondary degradation products exhibit toxicity; a correlation exists between the evolution of the intermediate compounds and the toxicity connected to them. Copyright (C) 2008 John Wiley & Sons, Ltd.
收起
摘要 :
The electronic structure of the magnetic refrigerant Gd5Ge2Si2 has been experimentally investigated by photoemission and x-ray absorption spectroscopy. The resonant photoemission and x-ray absorption measurements performed across ...
展开
The electronic structure of the magnetic refrigerant Gd5Ge2Si2 has been experimentally investigated by photoemission and x-ray absorption spectroscopy. The resonant photoemission and x-ray absorption measurements performed across the Gd N-4,N-5 and Gd M-4,M-5 edges identify the position of Gd 4f multiplet lines, and assess the 4f occupancy (4f(7)) and the character of the states close to the Fermi edge. The presence of Gd 5d states in the valence band suggests that an indirect 5d exchange mechanism underlies the magnetic interactions between Gd 4f moments in Gd5Ge2Si2. From 175 to 300 K the first 4 eV of the valence band and the Gd partial density of states do not display clear variations. A significant change is instead detected in the photoemission spectra at higher binding energy, around 5.5 eV, likely associated to the variation of the bonding and antibonding Ge( Si) s bands across the phase transition.
收起
摘要 :
We present novel infrared optical conductivity data on the three layer high T-c superconductor Bi2Sr2Ca2CU3O10 at optimal doping. We extend the analysis of an earlier publication, providing a universal scaling function sigma(omega...
展开
We present novel infrared optical conductivity data on the three layer high T-c superconductor Bi2Sr2Ca2CU3O10 at optimal doping. We extend the analysis of an earlier publication, providing a universal scaling function sigma(omega, T) = T(-1)g(omega/T) for the optical conductivity. In the present manuscript, we obtain a good scaling collapse of the experimental curves on the g(omega/T) over a wide range of values of omega/T (at least in range 0-10), if we assume that g(omega/T) is superimposed on a non-universal background which is temperature independent. We obtain the same result, if in our analysis we allow this background to have a T-2 temperature dependent correction. The most striking property of g(omega/T) is, that it corresponds to a scattering rate which varies linearly as a function of temperature, but which is independent of the frequency. (c) 2006 Elsevier Inc. All rights reserved.
收起
摘要 :
National legislation initiating projects for production of energy from renewable energy sources in protected areas of Italy is considered. The necessity to develop environmental policies preventing climate changes by reducing harm...
展开
National legislation initiating projects for production of energy from renewable energy sources in protected areas of Italy is considered. The necessity to develop environmental policies preventing climate changes by reducing harmful gases emissions accentuated in the Kyoto protocol through promotion of energy systems based on renewable energy sources is discussed. Investigations were conducted to study sustainability of a conventional energy system compared with one using renewable energy sources. Specific objectives included investigations of availability of local sources of biomass, availability of thermal energy produced, convenience of transition to the new form of heating, evaluation of social costs and benefits, and evaluation of finances and economy aspects of the new project. Part I of the article presents introductory concepts of cost benefit analysis, and Part II includes results of studies of economic aspects of the project. Methodological aspects of cost benefit analysis are outlined, and mathematical models used in calculations of costs and benefits are presented. Objectives of the forest-wood-energy project, i.e. production, preservation and storage of wood biomass, are considered. Data are tabulated on biomass requirements and the surface area of a forest used annually for biomass production. Diagrams are presented on costs of raw timber processed into biomass used for heating of a boiler, and comparative costs of thermal energy obtained with biomass and gas. Data are tabulated on the forest area, forest productivity and biomass production from forests in 7 municipalities of a protected area. Data are included on costs, benefits and cash flow analysis in euros. Data are provided on monetary and non-monetary social costs and benefits. It is concluded that the forest-wood-energy project improves the economic situation of the local communities, particularly through increasing employment. Positive effects of the project on control of carbon dioxide emissions and increase of the value of wood biomass are also considered..
收起
摘要 :
There is a discrepancy between the in vitro anergic state of CD4(+)CD25(hi)FoxP3(+) regulatory T (Treg) cells and their in vivo proliferative capability. The underlying mechanism of this paradox is unknown. Here we show that the a...
展开
There is a discrepancy between the in vitro anergic state of CD4(+)CD25(hi)FoxP3(+) regulatory T (Treg) cells and their in vivo proliferative capability. The underlying mechanism of this paradox is unknown. Here we show that the anergic state of Treg cells depends on the elevated activity of the mammalian target of rapamycin (mTOR) pathway induced by leptin: a transient inhibition of mTOR with rapamycin, before T cell receptor (TCR) stimulation, made Treg cells highly proliferative in the absence of exogenous interleukin-2 (IL-2). This was a dynamic and oscillatory phenomenon characterized by an early downregulation of the leptin-mTOR pathway followed by an increase in mTOR activation necessary for Treg cell expansion to occur. These data suggest that energy metabolism, through the leptin-mTOR-axis, sets responsiveness of Treg cells that use this information to control immune tolerance and autoimmunity.
收起
摘要 :
There is a discrepancy between the in vitro anergic state of CD4(+)CD25(hi)FoxP3(+) regulatory T (Treg) cells and their in vivo proliferative capability. The underlying mechanism of this paradox is unknown. Here we show that the a...
展开
There is a discrepancy between the in vitro anergic state of CD4(+)CD25(hi)FoxP3(+) regulatory T (Treg) cells and their in vivo proliferative capability. The underlying mechanism of this paradox is unknown. Here we show that the anergic state of Treg cells depends on the elevated activity of the mammalian target of rapamycin (mTOR) pathway induced by leptin: a transient inhibition of mTOR with rapamycin, before T cell receptor (TCR) stimulation, made Treg cells highly proliferative in the absence of exogenous interleukin-2 (IL-2). This was a dynamic and oscillatory phenomenon characterized by an early downregulation of the leptin-mTOR pathway followed by an increase in mTOR activation necessary for Treg cell expansion to occur. These data suggest that energy metabolism, through the leptin-mTOR-axis, sets responsiveness of Treg cells that use this information to control immune tolerance and autoimmunity.
收起
摘要 :
We have studied the photocatalytic transformation of atenolol, 4-[2-hydroxy-3-[(l-methyl)amino] propoxyllbenzeneacetamide, a cardioselective beta-blocking agent used to treat cardiac arrhythmias and hypertension, under simulated s...
展开
We have studied the photocatalytic transformation of atenolol, 4-[2-hydroxy-3-[(l-methyl)amino] propoxyllbenzeneacetamide, a cardioselective beta-blocking agent used to treat cardiac arrhythmias and hypertension, under simulated solar irradiation using titanium dioxide as photocatalyst. The investigation involved monitoring drug decomposition, identifying intermediate compounds, assessing mineralization, and evaluating toxicity. High-performance liquid chromatography (HPLC) coupled to high-resolution mass spectrometry (HRMS) via an electrospray ionization (ESI) interface was a powerful tool for the identification and measurement of the degradation products; 23 main species were identified. Intermediates were characterized through their chromatographic behavior and evolution kinetics, coupled with accurate mass information. Through the full analysis of MS and MSn spectra and a comparison with parent drug fragmentation pathways, the diverse isomers were characterized. Neither atenolol nor the intermediates formed exhibit acute toxicity. All intermediates are easily degraded and no compound identified could withstand 2h irradiation. Photomineralization of the substrate in terms of carbon mineralization and nitrogen release was rapid and, within 4h of irradiation, organic nitrogen and carbon were completely mineralized. Copyright (c) 2008 John Wiley & Sons, Ltd.
收起
摘要 :
Understanding the risks deriving from protracted exposure to low doses of ionizing radiation has remarkable societal importance in view of the large number of work settings in which sources of IR are encountered. To address this q...
展开
Understanding the risks deriving from protracted exposure to low doses of ionizing radiation has remarkable societal importance in view of the large number of work settings in which sources of IR are encountered. To address this question, we studied the frequency of micronuclei (MN), which is an indicator of DNA damage, in a population exposed to low levels of ionizing radiation and in matched controls. In both exposed population and controls, the possible influence of single nucleotide polymorphisms in XRCC1, XRCC3 and XPD genes on the frequency of micronuclei was also evaluated. We also considered the effects of confounding factors, like smoking status, age and gender. The results indicated that MN frequency was significantly higher in the exposed workers than in the controls [8.62+/-2.80 versus 6.86+/-2.65; P=0.019]. Radiological workers with variant alleles for XRCC1 or XRCC3 polymorphisms or wild-type alleles for XPD exon 23 or 10 polymorphisms showed a significantly higher MN frequency than controls with the same genotypes. Smoking status did not affect micronuclei frequency either in exposed workers or controls, while age was associated with increased MN frequency in the exposed only. In the combined population, gender but not age exerted an influence on the yield of MN, being higher in females than in males. Even though there is a limitation in this study due to the small number of subjects, these results suggest that even exposures to low level of ionizing radiation could have genotoxic effects and that XRCC3, XRCC1 and XPD polymorphisms might contribute to the increased genetic damage in susceptible individuals occupationally exposed to chronic low levels of ionizing radiation. For a clear conclusion on the induction of DNA damage caused by protracted exposure to low doses of ionizing radiation and the possible influence of genetic polymorphism in DNA repair genes larger studies are needed.
收起
摘要 :
Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome, whose pathogenesis begins with the accumulation of liver fat and is followed by the development of necro-inflammation and fibrosis. R...
展开
Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome, whose pathogenesis begins with the accumulation of liver fat and is followed by the development of necro-inflammation and fibrosis. Recent evidence indicates that adipocytokines, polypeptides secreted by the adispose tissue, might play an important role in the pathogeneic process and progression of NAFLD. In this review, we explore the role of leptin, and in part of other adipocytokines, in the interference with hepatic injury associated with fatty infiltration, in the modulation of steatosis and fibrosis, in both experimental models of the disease and in the clinical practice. We also discuss the potential use of leptin as non-invasive marker for differentiating simple fatty liver from NAFLD, and the possible novel therapeutic strategies aimed at interfering with the leptin axis to dampen chronic liver inflammation and NAFLD.
收起
原文获取