Geographic and sectoral characteristics of academic knowledge externalities

This note implements a novel approach to formalizing spatial externalities by employing spatial econometric methods that combine spatial dependence in the form of spatial autoregressive processes and spatial heterogeneity in the form of spatial regimes. The results confirm earlier findings that academic externalities are not uniform across sectors but also indicate important differences across sectors in terms of agglomeration effects. Received: 18 April 2000 / Accepted: 26 July 2000     

Effects of partially replacing dietary starch with dry glycerol in a lactating cow diet on ruminal fermentation during continuous culture

The effects of dry glycerol as a partial replacement for dietary starch in a lactating cow diet on ruminal fermentation and bacterial protein synthesis were evaluated using 4 single-flow, continuous-culture fermentors (ranging from 1,015 to 1,040 mL in volume). The basal lactating cow diet was formulated to have partial contents of dietary starch provided from a corn starch supplement [at 12.37% diet dry matter (DM)], which was partially or completely replaced by a dry glycerol product. Both the corn starch supplement and dry glycerol product contained 65% of pure corn starch or glycerol, respectively. The final inclusion rate for pure glycerol was at 0, 3, 5, or 8% of DM in the basal diet. The experiment was conducted using a 4 × 4 Latin square design with four 9-d periods, with the first 6 d for adaptation and last 3 d for sampling. Fermentors were inoculated with 1L of ruminal fluid and 25 g of ruminal digesta from a ruminally cannulated cow receiving a lactation total mixed ration (16% crude protein, 32% neutral detergent fiber, and 25% starch; DM basis). Each fermentor was fed 75 g of DM of its respective experimental diet daily in 3 equal portions (at 0800, 1400, and 2000 h). Liquid dilution rate of the fermentors was maintained at 10%/h and solids retention time was set at 24 h. Fermentation fluid and the effluent from each fermentor were sampled once daily (at 1330 h) from d 7 to 9 of each period and pooled by period. Postprandial ruminal fermentation was studied by sampling the fermentors hourly for 5 h after the 0800 h feeding on d 9 of each period. The total fermentation contents were harvested at the end of the period for estimations of bacterial protein synthesis. Replacing corn starch with dry glycerol linearly increased the proportions of propionate and valerate at the expense of acetate in the fermentation fluid measured daily or for the first 5h after feeding. Replacing corn starch with dry glycerol also linearly increased the digestibility of dietary neutral detergent fiber without a change on the flow or efficiency of bacterial protein synthesis during continuous culture. Results indicate that glycerol as a dry product can replace dietary starch as corn starch at a level of up to 8% of DM in the diet without negatively affecting ruminal fermentation and digestibility during continuous culture.     

Experimental assessment of heat storage properties and heat transfer characteristics of a phase change material slurry for air conditioning applications

A new microencapsulated phase change material slurry based on microencapsulated Rubitherm RT6 at high concentration (45% w/w) was tested. Some heat storage properties and heat transfer characteristics have been experimentally investigated in order to assess its suitability for the integration into a low temperature heat storage system for solar air conditioning applications. DSC tests were conducted to evaluate the cold storage capacity and phase change temperature range. A phase change interval of approximately 3 °C and a hysteresis behaviour of the enthalpy were identified. An experimental set-up was built in order to quantify the natural convection heat transfer occurring from a vertical helically coiled tube immersed in the phase change material slurry. First, tests were carried out using water in order to obtain natural convection heat transfer correlations. Then a comparison was conducted with the results obtained for the phase change material slurry. It was found that the values of the heat transfer coefficient for the phase change material slurry were higher than for water, under identical temperature conditions inside the phase change interval.     

Hemorheological and Microcirculatory Factors in Liver Ischemia-Reperfusion Injury—An Update on Pathophysiology,Molecular Mechanisms and Protective Strategies

Hepatic ischemia-reperfusion injury (IRI) is a multifactorial phenomenon which has been associated with adverse clinical outcomes. IRI related tissue damage is characterized by various chronological events depending on the experimental model or clinical setting. Despite the fact that IRI research has been in the spotlight of scientific interest for over three decades with a significant and continuous increase in publication activity over the years and the large number of pharmacological and surgical therapeutic attempts introduced, not many of these strategies have made their way into everyday clinical practice. Furthermore, the pathomechanism of hepatic IRI has not been fully elucidated yet. In the complex process of the IRI, flow properties of blood are not neglectable. Hemorheological factors play an important role in determining tissue perfusion and orchestrating mechanical shear stress-dependent endothelial functions. Antioxidant and anti-inflammatory agents, ischemic conditioning protocols, dynamic organ preservation techniques may improve rheological properties of the post-reperfusion hepatic blood flow and target endothelial cells, exerting a potent protection against hepatic IRI. In this review paper we give a comprehensive overview of microcirculatory, rheological and molecular–pathophysiological aspects of hepatic circulation in the context of IRI and hepatoprotective approaches.     

Adiponectin Deregulation in Systemic Autoimmune Rheumatic Diseases

Deregulation of adiponectin is found in systemic autoimmune rheumatic diseases (SARDs). Its expression is downregulated by various inflammatory mediators, but paradoxically, elevated serum levels are present in SARDs with high inflammatory components, such as rheumatoid arthritis and systemic lupus erythematosus. Circulating adiponectin is positively associated with radiographic progression in rheumatoid arthritis as well as with cardiovascular risks and lupus nephritis in systemic lupus erythematosus. However, in SARDs with less prominent inflammation, such as systemic sclerosis, adiponectin levels are low and correlate negatively with disease activity. Regulators of adiponectin gene expression (PPAR-γ, Id3, ATF3, and SIRT1) and inflammatory cytokines (interleukin 6 and tumor necrosis factor α) are differentially expressed in SARDs and could therefore influence total adiponectin levels. In addition, anti-inflammatory therapy could also have an impact, as tocilizumab treatment is associated with increased serum adiponectin. However, anti-tumor necrosis factor α treatment does not seem to affect its levels. Our review provides an overview of studies on adiponectin levels in the bloodstream and other biological samples from SARD patients and presents some possible explanations why adiponectin is deregulated in the context of therapy and gene regulation.