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Sufficient Quantities (sufficient + quantity)
Selected AbstractsCryogenic extinguishment of liquid pool firesPROCESS SAFETY PROGRESS, Issue 1 2010Yiannis Levendis Abstract Results on fire extinguishment using direct application of liquid nitrogen are presented in this article. This technique targets challenging fires, such as burning hazardous chemicals or fuels, in which cases prompt suppression or extinguishment is paramount to prevent explosions, avoid release of toxic fumes and avert environmental catastrophes. Liquid nitrogen is a rather environmentally benign extinguishing agent that does not cause property damage or groundwater contamination. Application of this cryogen onto a hot pyrolyzing/burning surface induces abrupt vaporization, spread and expansion. The pyrolyzing gases are inerted, the surface is cooled and hence its pyrolysis rate is reduced, air is separated from the fuel, and the fire extinguishes. To demonstrate this technique, experiments were conducted with pool fires of ethanol, propanol, and diesel fuel. To examine the underlying principles, analysis of the results was conducted based on simplified calculations. Sufficient quantities of the cryogen extinguished the fires nearly instantaneously. Half-liter quantities were sufficient to extinguish 1 m2 pool fires. The method of dispensing and distributing the cryogen on the pool fires proved to be of considerable importance. The existence of wind, which disturbed the flame, was not found to prevent extinguishment. © 2009 American Institute of Chemical Engineers Process Saf Prog 2010 [source] Released nucleotides amplify the cilium-dependent, flow-induced [Ca2+]i response in MDCK cellsACTA PHYSIOLOGICA, Issue 3 2009H. A. Praetorius Abstract Aim:, Changes in perfusate flow produce increases in [Ca2+]i in renal epithelial cells. Cultured renal epithelia require primary cilia to sense subtle changes in flow. In perfused kidney tubules this flow response is caused by nucleotide signalling via P2Y2 receptors. It is, however, not known whether nucleotides are released by mechanical stress applied to renal primary cilia. Here we investigate whether nucleotides are released during the cilium-dependent flow response and contribute to the flow-induced, cilium-dependent [Ca2+]i signal. Methods:, MDCK cells loaded with Fluo-4-AM were observed at 37 °C in semi-open single or closed-double perfusion chambers. Results:, Our data suggest a purinergic component of the cilium-dependent flow-response: (1) ATP scavengers and P2 receptor antagonists reduced (55%) the cilium-dependent flow-response; (2) ATP added at subthreshold concentration sensitized the renal epithelia to flow changes; (3) increases in fluid flow transiently enhanced the ATP concentration in the superfusate (measured by biosensor-cells). To test if nucleotides were released in sufficient quantities to stimulate renal epithelia we used non-confluent MDCK cells without cilia as reporter cells. We confirmed that non-confluent cells do not respond to changes in fluid flow. Placing confluent, ciliated cells upstream in the in-flow path of the non-confluent cells made them responsive to fluid flow changes. This phenomenon was not observed if either non-confluent or de-ciliated confluent cells were placed upstream. The [Ca2+]i -response in the non-confluent cells with ciliated cells upstream was abolished by apyrase and suramin. Conclusion:, This suggests that subtle flow changes sensed by the primary cilium induces nucleotide release, which amplifies the epithelial [Ca2+]i -response. [source] Glucose-responsive insulin-producing cells from stem cellsDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 6 2002David J. Kaczorowski Abstract Recent success with immunosuppression following islet cell transplantation offers hope that a cell transplantation treatment for type 1 (juvenile) diabetes may be possible if sufficient quantities of safe and effective cells can be produced. For the treatment of type 1 diabetes, the two therapeutically essential functions are the ability to monitor blood glucose levels and the production of corresponding and sufficient levels of mature insulin to maintain glycemic control. Stem cells can replicate themselves and produce cells that take on more specialized functions. If a source of stem cells capable of yielding glucose-responsive insulin-producing (GRIP) cells can be identified, then transplantation-based treatment for type 1 diabetes may become widely available. Currently, stem cells from embryonic and adult sources are being investigated for their ability to proliferate and differentiate into cells with GRIP function. Human embryonic pluripotent stem cells, commonly referred to as embryonic stem (ES) cells and embryonic germ (EG) cells, have received significant attention owing to their broad capacity to differentiate and ability to proliferate well in culture. Their application to diabetes research is of particular promise, as it has been demonstrated that mouse ES cells are capable of producing cells able to normalize glucose levels of diabetic mice, and human ES cells can differentiate into cells capable of insulin production. Cells with GRIP function have also been derived from stem cells residing in adult organisms, here referred to as endogenous stem cell sources. Independent of source, stem cells capable of producing cells with GRIP function may provide a widely available cell transplantation treatment for type 1 diabetes. Copyright © 2002 John Wiley & Sons, Ltd. [source] Measurement of specific radioactivity in proteins separated by two-dimensional gel electrophoresisELECTROPHORESIS, Issue 5-6 2006Shaobo Zhou Abstract We report a method to quantify the specific radioactivity of proteins that have been separated by 2-DE. Gels are stained with SyproRuby, and protein spots are excised. The SyproRuby dye is extracted from each spot using DMSO, and the fluorescence is quantified automatically using a plate reader. The extracted gel piece is then dissolved in hydrogen peroxide and radioactivity is quantified by liquid scintillation counting. Gentle agitation with DMSO for 24,h was found to extract all the SyproRuby dye from gel fragments. The fluorescence of the extract was linearly related to the amount of BSA loaded onto a series of 1-D gels. When rat muscle samples were run on 2-DE gels, the fluorescence extracted from 54,protein spots showed a good correlation (r = 0.79, p < 0.001) with the corresponding spot intensity measured by conventional scanning and image analysis. DMSO extraction was found not to affect the amount of radioactive protein left in the gel. When a series of BSA solutions of known specific radioactivity were run on 2-DE gels, the specific radioactivity measured by the new method showed a good correlation (r = 0.98, p < 0.01, n = 5) with the specific radioactivity measured directly before loading. Reproducibility of the method was measured in a series of 2-DE gels containing proteins from the livers of rats and mice that had been injected with [35S]methionine. Variability tended to increase when the amount of radioactivity in the protein spot was low, but for samples containing at least 10,dpm above background the CV was around 30%, which is comparable to that obtained when measuring protein expression by conventional image analysis of SyproRuby-stained 2-DE gels. Similar results were obtained whether spots were excised manually or using a spot excision robot. This method offers a high-throughput, cost-effective and reliable method of quantifying the specific radioactivity of proteins from metabolic labelling experiments carried out in,vivo, so long as sufficient quantities of radioactive tracer are used. [source] Effects of maternally transferred organochlorine contaminants on early life survival in a freshwater fishENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2005Thomas A. Johnston Abstract Laboratory research has shown that female fish can pass toxic organochlorines (OCs) from their bodies to their eggs, killing their offspring if sufficient quantities are transferred. We conducted a controlled incubation study using gametes from a wild, OC-contaminated walleye (Sander vitreus) population (Bay of Quinte, Lake Ontario, Canada) in order to assess among-female variation in offspring early life survival in relation to ova concentrations of planar OCs (polychlorinated dibenzo- p -dioxins and furans and planar polychlorinated biphenyls) and a suite of other maternal and ova characteristics. Equal volumes of ova from each female were fertilized, pooled, and incubated together as an experimental cohort. Relative survival of each female's offspring was estimated as the proportion of surviving larvae (at ,5 d posthatch) that she contributed to the cohort as determined by microsatellite DNA parentage assignment. Total planar OC concentration (expressed as toxic equivalency of 2,3,7,8-tetrachloro-dibenzo- p -dioxin) of ova was positively related to maternal age and size and to ova lipid content. However, early life survival did not decline with increasing ova planar OC concentrations. Similarly, we observed no significant relationships between early life survival and ova thiamine content, ova fatty acid composition, or maternal age or size. Early life survival was more strongly correlated with date of spawn collection, thyroid hormone status of the ova, and ovum size. Maternally transferred planar OCs do not appear to negatively influence female reproductive success in this walleye population. [source] C-terminal truncated cannabinoid receptor 1 coexpressed with G protein trimer in Sf9 cells exists in a precoupled state and shows constitutive activityFEBS JOURNAL, Issue 23 2007Chandramouli Reddy Chillakuri We have investigated the existence of a precoupled form of the distal C-terminal truncated cannabinoid receptor 1 (CB1-417) and heterotrimeric G proteins in a heterologous insect cell expression system. CB1-417 showed higher production levels than the full-length receptor. The production levels obtained in our expression system were double the values reported in the literature. We also observed that at least the distal C-terminus of the receptor was not involved in receptor dimerization, as was predicted in the literature. Using fluorescence resonance energy transfer, we found that CB1-417 and G,i1,1,2 proteins were colocalized in the cells. GTP,S binding assays with the Sf9 cell membranes containing CB1-417 and the G protein trimer showed that the receptor could constitutively activate the G,i1 protein in the absence of agonists. A CB1-specific antagonist (SR 141716A) inhibited this constitutive activity of the truncated receptor. We found that the CB1-417/G,i1,1,2 complex could be solubilized from Sf9 cell membranes and coimmunoprecipitated. In this study, we have proven that the receptor and G proteins can be coexpressed in higher yields using Sf9 cells, and that the protein complex is stable in detergent solution. Thus, our system can be used to produce sufficient quantities of the protein complex to start structural studies. [source] Donor site morbidity after harvesting of proximal tibia boneHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 6 2006Yuan-Chien Chen DDS Abstract Background. Bone-grafting procedures are common in head and neck surgery. Donor site morbidity is an important factor in deciding the site for harvest of cancellous bone. The tibia has been recommended as a harvest site. Use of the proximal tibia as a donor site is associated with few complications. Our present study used proximal tibia bone grafts to reconstruct maxillofacial defects and augment bone volume for implantation. Methods. A retrospective study was undertaken to analyze 40 proximal tibia bone grafts in maxillofacial reconstruction. Minimal follow-up was 6 months. Results. There were no major complications during the follow-up period. Early minor complications (15%) included temporary sensory loss and ecchymosis. Late minor complication (2.5%) was gait disturbance for 2 months. Long-term minor complication (2.5%) was an unsightly scar. Conclusion. The procedure for proximal tibia bone graft is easy, has less operative risk, and results in a lower postoperative morbidity rate. Based on our findings, we believe the proximal tibia offers a reliable site for harvest of sufficient quantities of good-quality cancellous bone. © 2006 Wiley Periodicals, Inc. Head Neck 28:496,500, 2006 [source] Uniform Nonspherical Colloidal Particles with Tunable Shapes,ADVANCED MATERIALS, Issue 15 2007J.-W. Kim A framework for large-scale synthesis of a variety of uniform nonspherical particle types (see figure) is introduced. The technique involves controlling the directionality of phase separations in the seeded-polymerization technique by manipulating the crosslinking density gradients of the dimer seed particles, thus allowing the obtainment of novel nonspherical particle shapes and the production of sufficient quantities to characterize their bulk properties. [source] Catalytic Asymmetric Synthesis of Oxindoles Bearing a Tetrasubstituted Stereocenter at the C-3 PositionADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2010Feng Zhou Abstract The 3,3,-disubstituted oxindole structural motif is a prominent feature in many alkaloid natural products, which include all kinds of tetrasubstituted carbon stereocenters, spirocyclic or not, all-carbon or heteroatom-containing. The catalytic asymmetric synthesis of the tetrasubstituted carbon stereocenter at the C-3 position of the oxindole framework integrates new synthetic methods and chiral catalysts, reflects the latest achievements in asymmetric catalysis, and facilitates the synthesis of sufficient quantities of related compounds as potential medicinal agents and biological probes. This review summarizes the recent progress in this area, and applications in the total synthesis of related bioactive compounds. [source] Efficacy of a standardized echinacea preparation (EchinilinTM) for the treatment of the common cold: a randomized, double-blind, placebo-controlled trialJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 1 2004V. Goel PhD Summary Background:, Recently, echinacea has regained popularity as one of the treatments chosen most commonly by consumers with the expectation that it will reduce the severity and duration of the common cold. However, the results from a limited number of clinical trials for this application have thus far been inconclusive. This incongruity may be the result of investigators utilizing poorly standardized echinacea products, likely devoid of sufficient quantities of active constituents necessary to exert a definitive clinical effect. Therefore, a formulation containing alkamides, cichoric acid, and polysaccharides at concentrations of 0·25, 2·5, and 25 mg/mL, respectively, was prepared from freshly harvested Echinacea purpurea plants (commercially available as Echinilin, Natural Factors Nutritional Products, Inc., Vancouver, BC, Canada). The objective of this study was to test the efficacy of this highly standardized formulation in reducing the severity and duration of symptoms of a naturally acquired common cold. Methods:, In a randomized, double-blind, placebo-controlled trial, 282 subjects aged 18,65 years with a history of two or more colds in the previous year, but otherwise in good health, were recruited. The subjects were randomized to receive either echinacea or placebo. They were instructed to start the echinacea or placebo at the onset of the first symptom related to a cold, consuming 10 doses the first day and four doses per day on subsequent days for 7 days. Severity of symptoms (10-point scale: 0, minimum; 9, maximum) and dosing were recorded daily. A nurse examined the subjects on the mornings of days 3 and 8 of their cold. Results:, A total of 128 subjects contracted a common cold (59 echinacea, 69 placebo). The total daily symptom scores were found to be 23·1% lower in the echinacea group than in placebo in those who followed all elements of the study protocol (P < 0·01). Throughout the treatment period, the response rate to treatments was greater in the echinacea group. A few adverse event profiles were observed in both groups. Conclusions:, Early intervention with a standardized formulation of echinacea resulted in reduced symptom severity in subjects with naturally acquired upper respiratory tract infection. Further studies with larger patient populations appear to be warranted. [source] MACROALGAL TISSUE NUTRIENTS AS INDICATORS OF NITROGEN AND PHOSPHORUS STATUS IN THE FLORIDA KEYSJOURNAL OF PHYCOLOGY, Issue 2000Hanisak M. D. This study used the tremendous biochemical and ecological diversity of macroalgae to assess nitrogen and phosphorus availability at a broad, ecosystem-level scale in the Florida Keys and nearby waters. Spatial variation in tissue nutrients (carbon, C; nitrogen, N; phosphorus, P) of dominant macroalgae were assessed, both as ratios and absolute values, along 12 inshore-offshore transects in the Florida Keys and at 10 stations in nearby Florida Bay. The resulting detailed analysis demonstrated spatial and temporal patterns in macroalgal tissue nutrients. The transect data revealed no universal inshore-offshore patterns in tissue nutrients and no obvious "hotspots" of nutrient enrichment. Similarly, when data were compared among segments, there was no universal geographical pattern in tissue nutrients for all species. The most striking result was that the N and P status of macroalgae in Florida Bay was significantly different than other locations. Macroalgae collected from Florida Bay generally had higher N and lower P levels than algae collected elsewhere. The most common inshore-offshore pattern was higher %N and lower %P availability inshore; however, limited inshore-offshore differences in N:P ratio suggests that both nutrients were generally readily available in proportional amounts required by the various species. Most species in this study had higher %N, and to a lesser extent, higher %P and %C in March than in July. Based on the published literature on other species of macroalgae, it appears that N and P are generally available in sufficient quantities that most macroalgal growth is not limited by either nutrient. [source] Plate-out in PVC extrusion.JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 1 2008Samples of extruder plate-out from industrial rigid PVC production lines were investigated by using a number of analytical techniques. The combined use of SEM-EDX (scanning electron microscopy , energy dispersive X-ray analysis), thermal analysis, FTIR (Fourier transform infrared spectrophotometry), and LIMA (laser-induced mass analysis) enabled most plate-out components to be identified and linked to likely formulation ingredients. The FTIR and thermal analyses were used to identify organic components. The FTIR analysis was also useful for identifying some inorganic compounds present in sufficient quantities, while EDX detected the elements present. The LIMA was the most sensitive technique, detecting trace quantities of both cations and anions. Calcium carbonate, titanium dioxide, and lead stabilizers were found in all die plate-out samples studied, together with small amounts of lubricants. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers. [source] Steller sea lions Eumetopias jubatus and nutritional stress: evidence from captive studiesMAMMAL REVIEW, Issue 4 2009DAVID A. S. ROSEN ABSTRACT 1Numbers of Steller sea lions Eumetopias jubatus in the North Pacific have declined. According to the nutritional stress hypothesis, this decline is due to reduced food availability. Data from studies conducted on pinnipeds in the laboratory are used here to test if the nutritional stress hypothesis can explain the decline of Steller sea lions. 2Overall, there is strong evidence for biologically meaningful differences in the nutritional quality of major prey species. Steller sea lions can partly compensate for low-quality prey by increasing their food consumption. 3There appear to be no detrimental effects of low-lipid prey on sea lion growth or body composition when sea lions can consume sufficient quantities of prey. However, the ability to increase consumption is physiologically limited, particularly in young animals. Overall, it is more difficult to maintain energy intake on a diet of low-quality prey than on a normal diet. 4Under conditions of inadequate food intake (either due to decreased prey availability or quality, or increased energy requirements) the overall impacts of nutritional stress are complex, and are dependent upon season, prey quality, age and the duration and intensity of the nutritional stress event. 5Studies on pinnipeds in the laboratory have been instrumental in identifying the conditions under which changes in sea lion prey can result in nutritional stress and the nature of the physiological impacts of nutritional stress events. [source] Can radical cations of the constituents of nucleic acids be formed in the gas phase using ternary transition metal complexes?,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 13 2005Sheena Wee Electrospray ionization (ESI) tandem mass spectrometry (MS/MS) of ternary transition metal complexes of [M(L3)(N)]2+ (where M,=,copper(II) or platinum(II); L3,=,diethylenetriamine (dien) or 2,2,:6,,2,-terpyridine (tpy); N,=,the nucleobases: adenine, guanine, thymine and cytosine; the nucleosides: 2,deoxyadenosine, 2,deoxyguanosine, 2,deoxythymine, 2,deoxycytidine; the nucleotides: 2,deoxyadenosine 5,-monophosphate, 2,deoxyguanosine 5,-monophosphate, 2,deoxythymine 5,-monophosphate, 2,deoxycytidine 5,-monophosphate) was examined as a means of forming radical cations of the constituents of nucleic acids in the gas phase. In general, sufficient quantities of the ternary complexes [M(L3)(N)]2+ could be formed for MS/MS studies by subjecting methanolic solutions of mixtures of a metal salt [M(L3)X2] (where M,=,Cu(II) or Pt(II); L3,=,dien or tpy; X,=,Cl or NO3) and N to ESI. The only exceptions were thymine and its derivatives, which failed to form sufficient abundances of [M(L3)(N)]2+ ions when: (a) M,=,Pt(II) and L3,=,dien or tpy; (b) M,=,Cu(II) and L3,=,dien. In some instances higher oligomeric complexes were formed; e.g., [Pt(tpy)(dG)n]2+ (n,=,1,13). Each of the ternary complexes [M(L3)(N)]2+ was mass-selected and then subjected to collision-induced dissociation (CID) in a quadrupole ion trap. The types of fragmentation reactions observed for these complexes depend on the nature of all three components (metal, auxiliary ligand and nucleic acid constituent) and can be classified into: (i) a redox reaction which results in the formation of the radical cation of the nucleic acid constituent, N+.; (ii) loss of the nucleic acid constituent in its protonated form; and (iii) fragmentation of the nucleic acid constituent. Only the copper complexes yielded radical cations of the nucleic acid constituent, with [Cu(tpy)(N)]2+ being the preferred complex due to suppression, in this case, of the loss of the nucleobase in its protonated form. The yields of the radical cations of the nucleobases from the copper complexes follow the order of their ionization potentials (IPs): G (lowest IP),>,A,>,C,>,T (highest IP). Sufficient yields of the radical cations of each of the nucleobases allowed their CID reactions (in MS3 experiments) to be compared to their even-electron counterparts. Copyright © 2005 John Wiley & Sons, Ltd. [source] Toward mechanistic elucidation of iron acquisition in barley: efficient synthesis of mugineic acids and their transport activitiesTHE CHEMICAL RECORD, Issue 2 2010Kosuke Namba Iron acquisition of graminaceous plants is characterized by the synthesis and secretion of iron-chelating compounds, mugineic acids (MAs), and by a specific uptake system for MAs-iron(III) complexes. We identified a transporter, HvYS1 (Hordeum vulgare L. yellow stripe 1), that is highly specific for MAs-iron(III) in barley roots. In this article we outline the characterization of HvYS1, and our recent work on the practical syntheses of MAs and investigations into the molecular basis of the specific transport of their iron(III) complexes by HvYS1. 2,-Deoxymugineic acid (DMA) was synthesized in a good overall yield from commercially available Boc-l-allylglycine using a minimal number of short simple operations with minimal protecting groups and work-up/purification procedures. The same strategy was also successfully applied to , -hydroxy-l-allylglycine, which was obtained by an allylic oxidation of l-allylglycine derivatives, to give MA and 2,-epi-MA efficiently. HvYS1 transported the iron(III) complexes of all three synthetic specimens with efficiency similar to that of a natural mugineic acid complex. With sufficient quantities of MAs in hand, we analyzed the function of HvYS1 and revealed by preparing chimeric transporters that the sixth outer membrane loop of the transporter plays a vital role in substrate specificity. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 140,150; 2010: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.200900028 [source] The problem of meeting dietary protein requirements in intensive aquaculture of marine fish larvae, with emphasis on Atlantic halibut (Hippoglossus hippoglossus L.)AQUACULTURE NUTRITION, Issue 3 2007A. KVÅLE Abstract Atlantic halibut (Hippoglossus hippoglossus) achieve a mature gastrointestinal tract approximately 2 months after first feeding (12 °C). The immature digestion may be the reason that compound diets fail to sustain growth and survival in first feeding halibut larvae and in larvae of other marine fish species. On the other hand, larvae fed with live feeds are capable of extraction of sufficient quantities of nutrients to sustain high growth rates. A lower availability of the protein in formulated diets compared with live prey is considered to be an important reason for the low performance of formulated diets. One approach to increase dietary protein availability is supplementation of pre-digested proteins. Experiments using tube fed individual larvae show that halibut larvae are able to utilize hydrolysed protein more efficiently than intact protein. However, Atlantic halibut in culture did not respond well to dietary supplementation of hydrolysed protein, in contrast to some other species. One reason may be extensive leaching of pre-hydrolysed proteins from the microparticulate feed. Atlantic halibut are slow feeders and may thus suffer more from nutrient leaching than species eating more rapidly. Feed formulation techniques affect dietary protein leaching, and in this paper, different techniques and their impact on feed properties are described. Microbound diets are most widely used in larval rearing, but show high rates of nutrient leaching. Lipid-based capsules seem to have the best potential to prevent leaching, however, they are not able to deliver a complete diet. The high need for improvements in larval feed formulation techniques are clearly stated, and some suggestions are given. Among these are production of complex particles, where small lipid-based capsules or liposomes containing the low molecular weight water-soluble nutrients are embedded. In such feed particles the water-soluble molecules are protected from leaching. Techniques for delivery of water-soluble nutrients that are needed in large quantities, i.e. free amino acids or hydrolysed and water-soluble protein, remain to be developed. [source] Environmental challenges in the energy sector: a chemical engineering perspective,ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2010Philippe A. Tanguy Abstract The supply of energy in sufficient quantities and the access to clean water are among the most significant global challenges to address in the decades to come, as these are key elements of human well-being and further development. These challenges are of course related, and future practices must consider their connectivity. As the present energy system is clearly reaching its limits in terms of sustainability, new approaches have been proposed based on much improved energy efficiency, development of renewable and new energy sources, and the use of carbon capture and storage for fossil resources. The industrial deployment of these alternate scenarios is intrinsically related to the availability of water on a large scale. Because the access to freshwater is becoming scarce in many countries, better water practices and the exploitation of new water resources must be developed for the supply of industrial water. This paper begins with a brief description of our present energy system based on fossil resources, this being a legacy of the industrial revolution. We then review the main drivers supporting the energy and water demand, and the constraints they are facing. The final section considers several chemical engineering challenges that arise when proposing ways of dealing with the energy-environment nexus in the future. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Framework for the Rapid Optimization of Soluble Protein Expression in Escherichia coli Combining Microscale Experiments and Statistical Experimental DesignBIOTECHNOLOGY PROGRESS, Issue 4 2007R. S. Islam A major bottleneck in drug discovery is the production of soluble human recombinant protein in sufficient quantities for analysis. This problem is compounded by the complex relationship between protein yield and the large number of variables which affect it. Here, we describe a generic framework for the rapid identification and optimization of factors affecting soluble protein yield in microwell plate fermentations as a prelude to the predictive and reliable scaleup of optimized culture conditions. Recombinant expression of firefly luciferase in Escherichia coli was used as a model system. Two rounds of statistical design of experiments (DoE) were employed to first screen (D-optimal design) and then optimize (central composite face design) the yield of soluble protein. Biological variables from the initial screening experiments included medium type and growth and induction conditions. To provide insight into the impact of the engineering environment on cell growth and expression, plate geometry, shaking speed, and liquid fill volume were included as factors since these strongly influence oxygen transfer into the wells. Compared to standard reference conditions, both the screening and optimization designs gave up to 3-fold increases in the soluble protein yield, i.e., a 9-fold increase overall. In general the highest protein yields were obtained when cells were induced at a relatively low biomass concentration and then allowed to grow slowly up to a high final biomass concentration, >8 g·L,1. Consideration and analysis of the model results showed 6 of the original 10 variables to be important at the screening stage and 3 after optimization. The latter included the microwell plate shaking speeds pre- and postinduction, indicating the importance of oxygen transfer into the microwells and identifying this as a critical parameter for subsequent scale translation studies. The optimization process, also known as response surface methodology (RSM), predicted there to be a distinct optimum set of conditions for protein expression which could be verified experimentally. This work provides a generic approach to protein expression optimization in which both biological and engineering variables are investigated from the initial screening stage. The application of DoE reduces the total number of experiments needed to be performed, while experimentation at the microwell scale increases experimental throughput and reduces cost. [source] The physician,patient relationship: the impact of patient-obtained medical informationHEALTH ECONOMICS, Issue 8 2006Bin Xie Abstract We investigate the impact of patient-obtained medical information (POMI) on the physician,patient relationship when patients, as a group, are heterogeneously informed and a physician's interests do not coincide with those of her patients. Introducing additional well-informed patients to the population discontinuously affects the physician's strategy, having no effect unless a sufficient quantity is added. When few patients are well informed, increasing the precision of their information level has no effect on the physician's strategy. Alternately, when a sufficient number of well-informed patients exists, increasing the precision of their information allows all patients to free-ride by receiving more appropriate treatment recommendations. Counterintuitively, we also identify circumstances under which increasing the general level of information may potentially harm patients. Copyright © 2006 John Wiley & Sons, Ltd. [source] Development of a minimally invasive epidermal abrasion device for clinical skin sampling and its applications in molecular biologyINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2009J.-M. Lee Synopsis A new abrasion tool (US patent US7087063 B2) has been developed for collecting skin epidermal samples. This device includes a central shaft that holds the probe in a split chuck. Of the variety of probe designs tested, the laser-cut hollow tube (HT) probe abraded the basal layer of the epidermis most consistently, resulting in representative epidermal skin samples. Compared with traditional clinical methods, the abrasion method allows for high-throughput epidermal skin collection with minimal invasiveness to the volunteer subjects. A large number of abrasion samples have been collected in various clinical studies with no adverse effects observed. Epidermal abrasion, when used appropriately and with the optimized probes, can yield high quality tissue samples that are representative of the epidermis. A sufficient quantity of RNA and protein can be obtained for many subsequent molecular and biochemical applications. Because of its minimal invasiveness and high-throughput nature, the abrasion method can be a valuable tool used to investigate the efficacy of topical applications of skin care products. Resume Un nouvel outil d'abrasion (US Patent US 7 087 063 B2) a été développé pour collecter des échantillons de peaux épidermiques. Cet instrument est constitué d'une tige centrale qui tient la sonde dans un mandrin fendu. Parmi tous les modèles de sondes testées, celle constituée d'un tube creux (HT) coupé au laser, abrase la couche basale de l'épiderme le plus régulièrement, conduisant ainsi à des échantillons de peaux épidermiques représentatifs. Comparée aux méthodes classiques, la méthode d'abrasion permet un prélèvement de peaux épidermiques haut débit avec un minimum d'invasion des sujets volontaires. Un grand nombre d'échantillons a été collecté dans diverses études cliniques sans qu'aucun effet adverse n'ait été observé. L'abrasion épidermique, quand elle est utilisée de façon appropriée et avec une sonde appropriée, peut conduire à des échantillons de haute qualité qui sont représentatifs de l'épiderme. Une quantité suffisante d'ARN et de protéines peut être obtenue en vue de tests moléculaires et biochimiques. Du fait de sa faible agressivité et de sa nature haut débit, la méthode d'abrasion peut être un outil précieux utilisé pour étudier l'efficacité des applications topiques de produits de soins cutanés. [source] Influences of climate on fire regimes in montane forests of north-western MexicoJOURNAL OF BIOGEOGRAPHY, Issue 8 2008Carl N. Skinner Abstract Aim, To identify the influence of interannual and interdecadal climate variation on the occurrence and extent of fires in montane conifer forests of north-western Mexico. Location, This study was conducted in Jeffrey pine (Pinus jeffreyi Grev. & Balf.)-dominated mixed-conifer forests in the central and northern plateau of the Sierra San Pedro Mártir, Baja California, Mexico. Methods, Fire occurrence was reconstructed for 12 dispersed sites for a 290-year period (1700,1990) from cross-dated fire-scarred samples extracted from live trees, snags and logs. Superposed epoch analysis was used to examine the relationships of tree-ring reconstructions of drought, the El Niño/Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) with fire occurrence and extent. Results, Years with no recorded fire scars were wetter than average. In contrast, years of widespread fires were dry and associated with phase changes of the PDO, usually from positive (warm) to negative (cold). The influence of the PDO was most evident during the La Niña phase of the ENSO. Widespread fires were also associated with warm/wet conditions 5 years before the fire. We hypothesize that the 5-year lag between warm/wet conditions and widespread fires may be associated with the time necessary to build up sufficient quantity and continuity of needle litter to support widespread fires. Two periods of unusually high fire activity (1770,1800 and 1920,1950) were each followed by several decades of unusually low fire activity. The switch in each case was associated with strong phase changes in both PDO and ENSO. Main conclusions, Climate strongly influences fire regimes in the mountains of north-western Mexico. Wet/warm years are associated with little fire activity. However, these years may contribute to subsequent fire years by encouraging the production of sufficient needle litter to support more widespread fires that occur in dry/cool years. [source] Oxidative metabolism by Thalassiosira weissflogii (Bacillariophyceae) of a diol-ester of okadaic acid, the diarrhetic shellfish poisoningJOURNAL OF PHYCOLOGY, Issue 2 2000Anthony J. Windust Previous investigations into the comparative toxicity of the diarrhetic shellfish poisoning (DSP) toxins to Thalassiosira weissflogii (Grun.) Fryxell et Hasle found that this diatom oxidatively metabolized okadaic acid diol-ester (OA diol-ester) to a more water-soluble product. This oxidative transformation of OA diol-ester by the diatom is significant for two reasons. First, it is known that dinophysistoxin-4 (DTX-4), the primary DSP toxin produced by the dinoflagellate Exuviaella lima (Ehr.) Butschli, will be hydrolyzed to the diol-ester following cell rupture (e.g. ingestion by a predator). Second, it implies that the ester, an uncharged, lipophilic intermediate, can easily enter cells and therefore may play an important role in the uptake and transfer of DSP toxins through the food web. It has been suggested that the water soluble DTX-4 may also be the form in which DSP toxins are excreted from the producing cell. Therefore, the stability of DTX-4 was examined when incubated either in fresh seawater medium into which washed cells of E. lima were introduced or in seawater medium conditioned by E. lima cells. Rapid hydrolysis of DTX-4 to the diol-ester took place in both cases. Thus, regardless of the route by which DTX-4 is liberated from the cell, either by cell disruption or excretion, the diol-ester will be the dominant form of the toxin to challenge associated organisms. To examine the metabolism of OA diol-ester by T. weissflogii in more detail, serial cultures of the diatom were challenged with OA diol-ester at a concentration of 2.0 ,g·mL,1. The metabolism and fate of the diol-ester in both cellular and medium fractions were monitored over 3 days using liquid chromatography with either ultraviolet (LC-UV) or mass spectrometric (LC-MS) detection. During the course of the experiment, all of the diol-ester was metabolized. LC-MS analysis revealed the presence of multiple oxidative products of OA diol-ester in the medium fraction, including a carboxylic acid derivative. The major metabolites were isolated in sufficient quantity to permit structural elucidation by NMR and MS. All the metabolites identified resulted from oxidation of the diol-ester side chain with the primary sites of attack at the terminal, subterminal, and unsaturated carbons. OA was found in both cellular and medium fractions, and its production was directly correlated with the metabolism of the diol-ester. The relative partitioning of both OA diol-ester and its oxidation products between cells and medium supports the contention that OA diol-ester can readily enter cells, be metabolized, and then excreted in more water-soluble forms. [source] Assessing the taxonomic status of dingoes Canis familiaris dingo for conservationMAMMAL REVIEW, Issue 2 2006AMANDA E. ELLEDGE ABSTRACT 1The conservation status of the dingo Canis familiaris dingo is threatened by hybridization with the domestic dog C. familiaris familiaris. A practical method that can estimate the different levels of hybridization in the field is urgently required so that animals below a specific threshold of dingo ancestry (e.g. 1/4 or 1/2 dingoes) can reliably be identified and removed from dingo populations. 2Skull morphology has been traditionally used to assess dingo purity, but this method does not discriminate between the different levels of dingo ancestry in hybrids. Furthermore, measurements can only be reliably taken from the skulls of dead animals. 3Methods based on the analysis of variation in DNA are able to discriminate between the different levels of hybridization, but the validity of this method has been questioned because the materials currently used as a reference for dingoes are from captive animals of unproven genetic purity. The use of pre-European materials would improve the accuracy of this method, but suitable material has not been found in sufficient quantity to develop a reliable reference population. Furthermore, current methods based on DNA are impractical for the field-based discrimination of hybrids because samples require laboratory analysis. 4Coat colour has also been used to estimate the extent of hybridization and is possibly the most practical method to apply in the field. However, this method may not be as powerful as genetic or morphological analyses because some hybrids (e.g. Australian cattle dog × dingo) are similar to dingoes in coat colour and body form. This problem may be alleviated by using additional visual characteristics such as the presence/absence of ticking and white markings. [source] Impact of changing diet regimes on Steller sea lion body conditionMARINE MAMMAL SCIENCE, Issue 2 2008Shannon Atkinson Abstract A leading theory for the cause of the decline of Steller sea lions is nutritional stress, which led to chronic high juvenile mortality and possibly episodic adult mortality. Nutritional stress may have resulted from either poor quality or low abundance of prey. The objective of this study was to determine whether we could predict shifts in body condition (i.e., body mass or body fat content) over different seasons associated with a change in diet (i.e., toward lower quality prey). Captive Steller sea lions (n= 3) were fed three different diet regimes, where Diet 1 approximated the diet in the Kodiak area in the 1970s prior to the documented decline in that area, Diet 2 approximated the species composition in the Kodiak area after the decline had begun, and Diet 3 approximated the diet in southeast Alaska where the Steller sea lion population has been increasing for over 25 yr. All the animals used in this study were still growing and gained mass regardless of diet. Body fat (%) varied between 13% and 28%, but was not consistently high or low for any diet regime or season. Mean intake (in kg) of Diet 2 was significantly greater for all sea lions during all seasons. All animals did, however, tend to gain less body mass on Diets 2 and 3, as well as during the breeding and postbreeding seasons. They also tended to gain more mass during the winter and on Diet 1, though these differences were not statistically significant. Thus, changing seasonal physiology of Steller sea lions appears to have more impact on body condition than quality of prey, provided sufficient quantity of prey is available. Steller sea lions are opportunistic predators and are evidently able to thrive on a variety of prey. Our results indicate that Steller sea lions are capable of compensating for prey of low quality. [source] Universal access to water and sanitation: Why the private sector must participateNATURAL RESOURCES FORUM, Issue 4 2003Terence Lee Abstract Against the background of the current state of provision of drinking water and sanitation in the world , with one billion lacking safe water, and 2.2 billion not having adequate sanitation , this article argues that private participation is necessary. The most important issues for the management of water utilities in the 21st century are identified as mobilizing investment for the highly capital intensive operation of water supply and sanitation infrastructure, and achieving efficiency in the delivery of services. The article highlights the issues that need to be raised if private investment is to be seriously considered as an alternative. Case studies, especially from Latin America (Argentina, Chile, Peru, Bolivia), illustrate different modes of private participation, and possible reasons for successes and failures are discussed. The article stresses that regardless of the modality of private sector involvement, on-going government regulatory responsibility in the water sector is crucial. It suggests that regulatory policy must go beyond just setting tariffs, to develop standards for drinking water quality and waste treatment, as well as other standards. In conclusion, the article recognizes that numerous and increasingly difficult challenges face utilities in fulfilling their responsibility to deliver drinking water of adequate quality, in sufficient quantity, and at affordable prices, as well as safe and sustainable disposal of wastewaters for members of urban and rural communities. [source] Nonadherence as a predictor of antidiabetic drug therapy intensification (augmentation),PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 9 2004Dr Stephen J. Kogut MBA Abstract Purpose To determine if nonadherence with antidiabetic drug therapy is predictive of subsequent antidiabetic drug therapy intensification. Methods We conducted a retrospective cohort study examining retail pharmacy dispensings of sulfonylureas or metformin to 1067 patients having diabetes. Patients that did not receive a sufficient quantity of medication to cover at least 80% of days during the evaluation period were classified as nonadherent. Outcomes identified were increase in the dose of antidiabetic medication utilized, the addition of a second antidiabetic agent to the regimen or either. Results Among users of sulfonylurea monotherapy, those classified as nonadherent were 45% more likely to intensify therapy in subsequent months as compared with those classified as adherent (age-adjusted odds ratio (OR) 1.45; 95% confidence interval (CI) 1.06,2.00). This finding was largely driven by observed increases in dosage, which were more likely among patients classified as nonadherent (age-adjusted OR 1.48, 95%CI 1.07,2.05). Nonadherence was not found to be predictive of the subsequent addition of a second antidiabetic agent (OR 1.02; 95%CI 0.64,1.63). Overall findings were similar for the smaller sample of patients receiving metformin monotherapy, though observed differences did not achieve statistical significance. Conclusions Patients who were poorly adherent to oral antidiabetic drug therapy more frequently experienced an increase in the dose of medication prescribed, as compared to patients that were classified as adherent. This finding underscores the need for prescribers to consider nonadherence as a root cause when patients fail to achieve therapeutic goals. Copyright © 2004 John Wiley & Sons, Ltd. [source] Overexpression and Characterization of the Rhodobacter sphaeroides PufX Membrane Protein in Escherichia coli,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2007Shiho Onodera Heterologous expression of the PufX membrane protein from purple photosynthetic bacterium Rhodobacter sphaeroides was attempted by using Escherichia (E.) coli cells. The PufX was overexpressed as a recombinant protein with a histidine tag added to the carboxyl terminus, and can be extracted from the cell membrane by various detergents. Circular dichroism measurements showed that the expressed PufX protein had ,-helix contents of 29% in organic solvents and 22,26% in 0.8,2.0% (w/v) n -octyl ,- d -glucopyranoside solutions, suggesting that the PufX contains a substantial ,-helical region composed of 18,22 amino acids. The PufX expressed in E. coli was examined by reconstitution experiments with LH1 ,- and ,-polypeptides and bacteriochlorophyll a. It was shown that the PufX inhibited not only the reconstitution of the LH1 complex, but also the formation of the B820 subunit type complex at high concentrations, indicating that the expressed PufX is biologically active. Large-scale expression of the functional PufX membrane protein provides sufficient quantity for further biophysical and structural analyses of its biological function, and adds another example for producing highly hydrophobic integral membrane proteins using the E. coli expression system. [source] Effects of bottom substrate and presence of shelter in experimental tanks on growth and survival of signal crayfish, Pacifastacus leniusculus (Dana) juvenilesAQUACULTURE RESEARCH, Issue 4 2003R Savolainen Abstract The effects of tank bottom substrates and presence of shelter on growth, survival and condition of cheliped in the juvenile (stage 2) signal crayfish, Pacifastacus leniusculus (Dana), with an initial stocking density of 200 individuals m,2 were investigated. In the first trial, three different tank bottom substrates with or without shelter were used. The three bottom types were loose gravel, glued gravel and bare bottom. The fastest growth both in terms of wet weight and carapace length was observed on loose gravel bottom. Also survival (range 30.1% to 49.8%) was affected by bottom type being higher on gravel bottoms than on bare bottom. Shelter improved survival only on loose gravel bottom. Bottom type influenced also the number of animals with cheliped injuries. The highest proportion of animals with no injuries (59.5%) was found on bare bottom and the proportion was about 12% and 13% units less on loose gravel and on glued gravel bottom. The presence of shelter had a marginal probability in increasing the number of animals without injuries. In the second trial, the substitution of ordinary gravel as tank bottom substrate with crushed limestone was studied. The mean final wet weights were 0.517 g on ordinary gravel bottom and 0.481 g on limestone bottom. The survivals were about 74% and 80% respectively. Limestone bottom decreased marginally final wet weight, and increased survival but did not affect the final carapace length that had a mean value of 13.6 mm. We conclude from the present experiments that the type of tanks and the rearing system used supported good growth of juvenile signal crayfish. The best growth results could be obtained by using loose gravel (or loose limestone) on the bottom of the tanks with a sufficient quantity of hiding places. However, there appears to be an increased risk for cheliped injuries on bottoms with loose materials. [source] Film-forming process and biocide assessment of high-molecular-weight chitosan as determined by combined ATR-FTIR spectroscopy and antimicrobial assaysBIOPOLYMERS, Issue 6 2006P. Fernandez-Saiz Abstract This pioneering study reported about the film-forming properties of high-molecular-weight chitosan as followed in situ by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, and has implications in fields such as biomedical, pharmaceutical, packaging, and coating applications. From the results, it was observed that immediately after dissolution in an acetic acid aqueous solution and subsequent casting over the ATR crystal, the formed carboxylate antimicrobial (NH,OOCH) species are not stable in the film formulation and become reduced over time; further assays confirmed previous research, which suggested that the presence and stability of these groups is strongly dependent, among other factors, on storage conditions. As-received chitosan and chitosan neutralized in NaOH films did not exhibit biocide performance towards Staphylococcus aureus. The antimicrobial tests were also found to strongly relate the presence of a sufficient quantity of these carboxylate groups to the chitosan activity as a biocide agent. Moreover, a novel methodology based on the use of a normalized infrared band centered at 1405 cm,1 is proposed which can be correlated with the antimicrobial character of the biopolymer. © 2006 Wiley Periodicals, Inc. Biopolymers 83: 577,583, 2006 This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] Differentiation and lineage selection of mouse embryonic stem cells in a stirred bench scale bioreactor with automated process controlBIOTECHNOLOGY & BIOENGINEERING, Issue 7 2005Magnus Schroeder Abstract It is well established that embryonic stem (ES) cells can differentiate into functional cardiomyocytes in vitro. ES-derived cardiomyocytes could be used for pharmaceutical and therapeutic applications, provided that they can be generated in sufficient quantity and with sufficient purity. To enable large-scale culture of ES-derived cells, we have developed a robust and scalable bioprocess that allows direct embryoid body (EB) formation in a fully controlled, stirred 2 L bioreactor following inoculation with a single cell suspension of mouse ES cells. Utilizing a pitched-blade-turbine, parameters for optimal cell expansion as well as efficient ES cell differentiation were established. Optimization of stirring conditions resulted in the generation of high-density suspension cultures containing 12.5,×,106 cells/mL after 9 days of differentiation. Approximately 30%,40% of the EBs formed in this process vigorously contracted, indicating robust cardiomyogenic induction. An ES cell clone carrying a recombinant DNA molecule comprised of the cardiomyocyte-restricted alpha myosin heavy chain (,MHC) promoter and a neomycin resistance gene was used to establish the utility of this bioprocess to efficiently generate ES-derived cardiomyocytes. The genetically engineered ES cells were cultured directly in the stirred bioreactor for 9 days, followed by antibiotic treatment for another 9 days. The protocol resulted in the generation of essentially pure cardiomyocyte cultures, with a total yield of 1.28,×,109 cells in a single 2 L bioreactor run. This study thus provides an important step towards the large-scale generation of ES-derived cells for therapeutic and industrial applications. © 2005 Wiley Periodicals, Inc. [source] | ||||||||||||||||||||||