Lipopolysaccharide inhibits or accelerates biomedical titanium corrosion depending on environmental acidity

Titanium and its alloys are routinely used as biomedical implants and are usually considered to be corrosion resistant under physiological conditions. However, during inflammation, chemical modifications of the peri-implant environment including acidification occur. In addition certain biomolecules including lipopolysaccharide (LPS), a component of Gram-negative bacterial cell walls and driver of inflammation have been shown to interact strongly with Ti and modify its corrosion resistance. Gram-negative microbes are abundant in biofilms which form on dental implants. The objective was to investigate the influence of LPS on the corrosion properties of relevant biomedical Ti substrates as a function of environmental acidity. Inductively coupled plasma mass spectrometry was used to quantify Ti dissolution following immersion testing in physiological saline for three common biomedical grades of Ti (ASTM Grade 2, Grade 4 and Grade 5). Complementary electrochemical tests including anodic and cathodic polarisation experiments and potentiostatic measurements were also conducted. All three Ti alloys were observed to behave similarly and ion release was sensitive to pH of the immersion solution. However, LPS significantly inhibited Ti release under the most acidic conditions (pH 2), which may develop in localized corrosion sites, but promoted dissolution at pH 4–7, which would be more commonly encountered physiologically. The observed pattern of sensitivity to environmental acidity of the effect of LPS on Ti corrosion has not previously been reported. LPS is found extensively on the surfaces of skin and mucosal penetrating Ti implants and the findings are therefore relevant when considering the chemical stability of Ti implant surfaces in vivo

Simulation for (sustainable) building design: Czech experiences

This paper attempts to outline the current state-of-the-art in the Czech Republic regarding the use of integrated building performance simulation as a design tool. Integrated performance simulation for reducing the environmental impact of buildings is illustrated by means of three recent HVAC selection and design studies for the new "Indonesian Jungle" pavilion in the Prague Zoo, for conversion of a historical building (water mill) into a museum, and for a city center office with thermal comfort complaints. The paper elaborates the modeling and simulation work that was carried out to support the design teams of the above projects. This includes a discussion on how the simulation results were transformed in relevant design information. The paper finishes by indicating directions for future work that is needed to be better equipped in order to address design problems such as the one indicated above

Simulation to support sustainable HVAC design for two historical buildings in Prague

This paper attempts to outline the current state-of-the-art in the Czech Republic regarding the use of integrated building performance simulation as a design tool. Integrated modeling and simulation of buildings is illustrated by means of two recent studies for conversion of historical buildings (a water mill and a former church; both dated back to the 14th century) into a museum and a concert hall respectively. The paper elaborates the modeling and simulation work that was carried out to support the design teams of the two projects. This includes a discussion on how the simulation results were transformed in relevant design information. The paper finishes by indicating directions for future work that is needed to be better equipped in order to address design problems in the field of construction or restoration of buildings and their heating, ventilation and air-conditioning systems

Simulation for (sustainable) building design: Czech experiences

This paper attempts to outline the current state-of-the-art in the Czech Republic regarding the use of integrated building performance simulation as a design tool. Integrated performance simulation for reducing the environmental impact of buildings is illustrated by means of three recent HVAC selection and design studies for the new "Indonesian Jungle" pavilion in the Prague Zoo, for conversion of a historical building (water mill) into a museum, and for a city center office with thermal comfort complaints. The paper elaborates the modeling and simulation work that was carried out to support the design teams of the above projects. This includes a discussion on how the simulation results were transformed in relevant design information. The paper finishes by indicating directions for future work that is needed to be better equipped in order to address design problems such as the one indicated above

ESP-r: integrated simulation tool for design of buildings and systems

The paper attempts to outline the capabilities of the ESP-r simulation software used as a design tool for buildings and HVAC systems. This state-of-the-art application of building performance simulation is illustrated by means of three recent studies concerning a new office building development, conversion of historical building into a concert hall, and a special zoo pavilion. The paper elaborates the modelling and simulation work that was carried out to support the design teams of the three projects. This includes a discussion on how the simulation results were transformed in relevant design information

An approach to teaching and research of simulation for environmental engineering design

This paper starts out by elaborating why computer modeling and simulation is such an important technique/ tool for modern state-of-the-art environmental engineering. It then continues with how this is currently integrated in engineering analysis and design. The paper continues with describing what we do in this field in terms of teaching and research. The paper finishes with indications for (our) future work in this area

Building performance simulation as a design tool for refurbishment of buildings

This paper attempts to outline the current state-of-the-art regarding the use of building performance simulation as a design tool for refurbishment of buildings. This is illus-trated by means of three recent studies for conversion of historical buildings (an early 20th century factory, and a water mill and a former church both dating back to the 14th century) into an office development, a museum gallery and a concert hall respectively. The paper elaborates the modeling and simulation work that was carried out to support the design teams of the three projects. This includes a discussion on how the simula-tion results were transformed in relevant design information. The paper finishes by indicating directions for future work that is needed to be better equipped in order to address design problems in the field of construction or restoration of buildings and their heating, ventilation and air-conditioning systems