Parametric exploration of the liver by magnetic resonance methods

MRI, as a completely noninvasive technique, can provide quantitative assessment of perfusion, diffusion, viscoelasticity and metabolism, yielding diverse information about liver function. Furthermore, pathological accumulations of iron and lipids can be quantified. Perfusion MRI with various contrast agents is commonly used for the detection and characterization of focal liver disease and the quantification of blood flow parameters. An extended new application is the evaluation of the therapeutic effect of antiangiogenic drugs on liver tumours. Novel, but already widespread, is a histologically validated relaxometry method using five gradient echo sequences for quantifying liver iron content elevation, a measure of inflammation, liver disease and cancer. Because of the high perfusion fraction in the liver, the apparent diffusion coefficients strongly depend on the gradient factors used in diffusion-weighted MRI. While complicating analysis, this offers the opportunity to study perfusion without contrast injection. Another novel method, MR elastography, has already been established as the only technique able to stage fibrosis or diagnose mild disease. Liver fat content is accurately determined with multivoxel MR spectroscopy (MRS) or by faster MRI methods that are, despite their widespread use, prone to systematic error. Focal liver disease characterisation will be of great benefit once multivoxel methods with fat suppression are implemented in proton MRS, in particular on high-field MR systems providing gains in signal-to-noise ratio and spectral resolution

Potential of carbonic anhydrase and urease bacteria for sequestration of CO

The present study aimed to investigate the potential of bacterial strains from cement kiln dust (CKD) to sequestrate atmospheric CO2 into aerated concrete as a functional for carbonic anhydrase (CA) and urease enzymes. Five samples of CKD was collected from Cement Industries of Malaysia Berhad (CIMA). The most potent bacterial isolates were selected and adapted to grow in 5% of CO2 and in bio-aerated concrete medium. CA enzyme was detected by using a solution of 1.8 g of p-NPA (p-nitrophenyl acetate) and 25 mg of ampicillin at 7-pH. The results of thioglycolate broth medium assay indicated that the bacterial isolates were facultative anaerobic. Furthermore, the results of candle jar test reflected that the bacterial isolates have the ability to survive with 5% of CO2 concentrations. Two bacterial isolates distinctly grow in bio-aerated concrete simulation medium, while only one bacterial isolate was the most potent and has produced in a powder form using freeze dryer to be ready to apply in bio-aerated concrete

Potential of carbonic anhydrase and urease bacteria for sequestration of CO2 into aerated concrete

The present study aimed to investigate the potential of bacterial strains from cement kiln dust (CKD) to sequestrate atmospheric CO2 into aerated concrete as a functional for carbonic anhydrase (CA) and urease enzymes. Five samples of CKD was collected from Cement Industries of Malaysia Berhad (CIMA). The most potent bacterial isolates were selected and adapted to grow in 5% of CO2 and in bio-aerated concrete medium. CA enzyme was detected by using a solution of 1.8 g of p-NPA (p-nitrophenyl acetate) and 25 mg of ampicillin at 7-pH. The results of thioglycolate broth medium assay indicated that the bacterial isolates were facultative anaerobic. Furthermore, the results of candle jar test reflected that the bacterial isolates have the ability to survive with 5% of CO2 concentrations. Two bacterial isolates distinctly grow in bio-aerated concrete simulation medium, while only one bacterial isolate was the most potent and has produced in a powder form using freeze dryer to be ready to apply in bio-aerated concrete

Alkaliphiles : The Emerging Biological Tools Enhancing Concrete Durability

Concrete is one of the most commonly used building materials ever used. Despite it is a very important and common construction material, concrete is very sensitive to crack formation and requires repair. A variety of chemical-based techniques and materials have been developed to repair concrete cracks. Although the use of these chemical-based repair systems are the best commercially available choices, there have also been concerns related to their use. These repair agents suffer from inefficiency and unsustainability. Most of the products are expensive and susceptible to degradation, exhibit poor bonding to the cracked concrete surfaces, and are characterized by different physical properties such as thermal expansion coefficients which are different to that of concrete. Moreover, many of these repair agents contain chemicals that pose environmental and health hazards. Thus, there has been interest in developing concrete crack repair agents that are efficient, long lasting, safe, and benign to the environment and exhibit physical properties which resemble that of the concrete. The search initiated by these desires brought the use of biomineralization processes as tools in mending concrete cracks. Among biomineralization processes, microbially initiated calcite precipitation has emerged as an interesting alternative to the existing chemical-based concrete crack repairing system. Indeed, results of several studies on the use of microbial-based concrete repair agents revealed the remarkable potential of this approach in the fight against concrete deterioration. In addition to repairing existing concrete cracks, microorganisms have also been considered to make protective surface coating (biodeposition) on concrete structures and in making self-healing concrete. Even though a wide variety of microorganisms can precipitate calcite, the nature of concrete determines their applicability. One of the important factors that determine the applicability of microbes in concrete is pH. Concrete is highly alkaline in nature, and hence the microbes envisioned for this application are alkaliphilic or alkali-tolerant. This work reviews the available information on applications of microbes in concrete: repairing existing cracks, biodeposition, and self-healing. Moreover, an effort is made to discuss biomineralization processes that are relevant to extend the durability of concrete structures