Biological upgrading of heavy crude oil

Heavy crudes (bitumen) are extremely viscous and contain high concentrations of asphaltene, resins, nitrogen and sulfur containing heteroaromatics and several metals, particularly nickel and vanadium. These properties of heavy crude oil present serious operational problems in heavy oil production and downstream processing. There are vast deposits of heavy crude oils in many parts of the world. In fact, these reserves are estimated at more than seven times the known remaining reserves of conventional crude oils. It has been proven that reserves of conventional crude oil are being depleted, thus there is a growing interest in the utilization of these vast resources of unconventional oils to produce refined fuels and petrochemicals by upgrading. Presently, the methods used for reducing viscosity and upgradation is cost intensive, less selective and environmentally reactive. Biological processing of heavy crudes may provide an ecofriendly alternative or complementary process with less severe process conditions and higher selectivity to specific reactions to upgrade heavy crude oil. This review describes the prospects and strengths of biological processes for upgrading of heavy crude oil.     

Biological imaging software tools

Few technologies are more widespread in modern biological laboratories than imaging. Recent advances in optical technologies and instrumentation are providing hitherto unimagined capabilities. Almost all these advances have required the development of software to enable the acquisition, management, analysis and visualization of the imaging data. We review each computational step that biologists encounter when dealing with digital images, the inherent challenges and the overall status of available software for bioimage informatics, focusing on open-source options.     

Biological verification of heavy ion treatment planning

Chinese hamster ovary (CHO) cells and thermoluminescent detectors (TLD-700) were used for physical and biological verification of heavy ion treatment planning. Experiments were performed in a cylindrical water phantom, in some cases with lung and bone equivalent material in front of the target volume. The results confirm the possibility of using thermoluminescent detectors for a quantitative verification of dose distributions. CHO cells can be used at least for qualitative dose verification. Received: 15 December 1997 / Accepted in revised form: 6 February 1998     

Biological applications of second harmonic imaging

Second Harmonic Generation (SHG) microscopy dates back to 1974, but effective biological use of the technique has a history of barely 10 years. It is now widely used to image collagen in many different applications, and is becoming useful for imaging myosin and some polysaccharides. A separate line on research has focussed on SHG dyes, which can provide high-speed indication of membrane potential and are now in use in neurobiology. This review looks at the progress to date in these different fields.     

Biological methods for speciation of heavy metals: different approaches

Heavy metals are found in their different forms in the environment. The distribution, mobility, and toxicity of metals are strongly related to these different forms. This necessitates the exploration of different methods for the remediation and speciation of heavy metals. Some direct and indirect physico-chemical methods such as filtration, chemical precipitation, ion-exchange, electro deposition, and membrane systems have been used for the last four decades. However, it is only in last few years that reliable biological methods have also been used. The biological methods include the use of microorganisms (fungi, algae, bacteria), plants (live or dead) and biopolymers. The use of these methods for the speciation of heavy metals is reviewed here.     

Following tracks of hemichannels

It has been suggested that plasma membrane-bound hemichannels perform physiological and pathophysiological functions per se. Such functions require the presence of hemichannels on the cell surface and their accessibility to the extracellular environment for at least some limited period of time. We have previously shown that hemichannels can be labeled by means of antibodies directed to an external loop domain of connexin (Cx) 43. We now provide evidence that trafficking of hemichannel vesicles can be visualized upon binding of a labeled homophilic peptide corresponding to a region of the first extracellular loop (EL1) of Cx43. In vivo imaging was performed after labeling hemichannels from the extracellular site with a mimetic peptide tagged with a fluorochrome (Alexa-546). Using a Cx43-CFP transfected HeLa cell line for incubation with the mimetic peptide, a significant number of double-labeled vesicles were found inside the cells. This double labeling indicates that a portion of Cx43 within the cell had accessed the cell surface as hemichannels where it bound to the peptide and was subsequently endocytosed. Pulse labeling with the peptide showed a decrease in the number of dual-labeled vesicles over time, indicating degradation and/or concurrent recycling of hemichannel vesicles.     

人类演化的痕迹

从形态学、胚胎学和分子生物学等3个方面系统的论述了人类在演化过程中所留下的具有动物特征的痕迹,并在胚胎发育、智齿、肌肉、婚姻、性别、身高等多方面对人类未来的演化趋势进行了合理的推断。     

Biological removal of pyridine in heavy oil byRhodococcus sp. KCTC 3218

The removal of organic nitrogen compounds present in crude perroleum and shale oils poses a challenging problem in petroleum industries. The deleterious effect of nitrogen compounds on cracking catalysts and the indication that they contribute to gum formation in gasolines are some of these aspects. Pyridine, a representative nitrogen compound in gaavy oil—was degraded byRhodoccus sp. KCTC 3218 in a water-heavy oil two-phase system. The pyridine degradation rate was affected by the presence of hydrocarbons such as n-hexadecane. This microorganism formed flocs which could be a barrier to mass transfer between the cells in flocs and the pyridine dissolved in water. This problem could be overcome by the addition of a surfactant such as Triton X-100. The ratio of water to heavy oil was important to separate the heavy oil phase from the water phase after treating the heavy oil. The culture medium was emulsified by a sort of biosurfactant secreted by this microorganism. The emulsified oil phase returned to its natural state when the ratio of water to heavy oil was 1.5. Above this ratio, the emulsified oil phase remained an emulsion after decantation. Pyridine in heavy oil was completely degraded in 15 hr at this water to heavy oil ratio of 1.5 when the concentration of pyridine in heavy oil was 700 ppm and the cell concentration was 0.32 g DCW/L.     

Life on two tracks

There are,I think,several factors that contribute to wisdom.Of these I should put first a sense of proportion: the capacity to take account of all the important factors in a problem and to attach to each its due weight.This has become more difficult than it used to be owing to the extent and complexity of the specialized knowledge     

Managing heavy metal toxicity stress in plants: Biological and biotechnological tools

The maintenance of ion homeostasis in plant cells is a fundamental physiological requirement for sustainable plant growth, development and production. Plants exposed to high concentrations of heavy metals must respond in order to avoid the deleterious effects of heavy metal toxicity at the structural, physiological and molecular levels. Plant strategies for coping with heavy metal toxicity are genotype-specific and, at least to some extent, modulated by environmental conditions. There is considerable interest in the mechanisms underpinning plant metal tolerance, a complex process that enables plants to survive metal ion stress and adapt to maintain growth and development without exhibiting symptoms of toxicity. This review briefly summarizes some recent cell biological, molecular and proteomic findings concerning the responses of plant roots to heavy metal ions in the rhizosphere, metal ion-induced reactions at the cell wall-plasma membrane interface, and various aspects of heavy metal ion uptake and transport in plants via membrane transporters. The molecular and genetic approaches that are discussed are analyzed in the context of their potential practical applications in biotechnological approaches for engineering increased heavy metal tolerance in crops and other useful plants.     

Stopping ras in its tracks

Ras interacts with many downstream effectors that regulate complex cytoplasmic signaling networks. In this issue, Gupta et al. (2007) use mouse models of Ras-mediated tumorigenesis to show that the interaction of Ras with a single isoform of phosphatidylinositol 3-kinase (PI3K), called p110alpha (PIK3CA), is critical for tumor formation. This result will stimulate re-evaluation of pharmacological approaches to target Ras for cancer treatment.     

Biological effects of exposure to magnetic resonance imaging: an overview

The literature on biological effects of magnetic and electromagnetic fields commonly utilized in magnetic resonance imaging systems is surveyed here. After an introduction on the basic principles of magnetic resonance imaging and the electric and magnetic properties of biological tissues, the basic phenomena to understand the bio-effects are described in classical terms. Values of field strengths and frequencies commonly utilized in these diagnostic systems are reported in order to allow the integration of the specific literature on the bio-effects produced by magnetic resonance systems with the vast literature concerning the bio-effects produced by electromagnetic fields. This work gives an overview of the findings about the safety concerns of exposure to static magnetic fields, radio-frequency fields, and time varying magnetic field gradients, focusing primarily on the physics of the interactions between these electromagnetic fields and biological matter. The scientific literature is summarized, integrated, and critically analyzed with the help of authoritative reviews by recognized experts, international safety guidelines are also cited.