Isolating conifer DNA: a superior polysaccharide elimination method

Genomic DNA was isolated from frozen needles of maturePinus radiata clones using a modified extraction technique incorporating cetyltrimethylammonium bromide (CTAB) for cell lysis. A high sodium chloride concentration (2 M) was used at 2 stages of the extraction procedure to eradicate polysaccharides, yielding pure genomic DNA suitable for restriction enzyme digestion and PCR amplification. Extractions were scaled down to suit 1.5-mL Eppendorf tubes, allowing easier handling and enhanced sterility.

The charge effect of cationic surfactants on the elimination of fibre beads in the electrospinning of polystyrene

Polystyrene nanofibres were electrospun with the inclusion of cationic surfactants, dodecyltrimethylammonium bromide (DTAB) or tetrabutylammonium chloride (TBAC), in the polymer solution. A small amount of cationic surfactant effectively stopped the formation of beaded fibres during the electrospinning. The cationic surfactants were also found to improve the solution conductivity, but had no effect on the viscosity. Only DTAB had an effect on the surface tension of the polymer solution, the surface tension decreasing slightly with an increase in the concentration of DTAB.

The formation of beaded fibres was attributed to an insufficient stretch of the filaments during the whipping of the jet, due to a low charge density. Adding the cationic surfactants improved the net charge density that enhanced the whipping instability. The jet was stretched under stronger charge repulsion and at a higher speed, resulting in an exhaustion of the bead structure. In addition, a polymer/surfactant interaction was found in the polystyrene–DTAB solution system, while this interaction was not found in the polystyrene–TBAC system. The polymer/surfactant interaction led to the formation of thinner fibres than those formed in the absence of the interaction.

The effects of a non-ionic surfactant, Triton X-405, on the electrospun fibres were also studied. The addition of Triton X-405 did not eliminate the fibre beads, but reduced the bead numbers and changed the morphology. Triton X-405 slightly improved the solution conductivity, and had a minor effect on the surface tension, but no effect on the viscosity.

Use of pineapple juice for elimination of egg stickiness of common carp (Cyprinus carpio L.)

Four treatments including three different concentrations of pineapple solution (I %, 3%, 5%) and the traditional method (salt/urea/tannin solutions) were used to eliminate egg stickiness of common carp. With the traditional method, fertilization and hatching rates were 74.5% ± 1.2 and 70.2% ± 1.1, respectively. The highest fertilization rate (89.3% ± 0.7) and hatching rate (86.6% ± 1.4) were found with treatment of 1% pineapple juice solution and was significantly different from those obtained with other treatments (P<0.05). Using pineapple juice for desticking common carp eggs also reduced the time of egg handling from almost one hour required with the traditional method, to about three minutes, as well as increasing fertilization and hatching rate under hatchery conditions.

Single transferable vote with Borda elimination: proportional representation, moderation, quasi-chaos and stability

Modifying single transferable vote (STV) by removing candidates according to their Borda scores creates a new vote counting system (STV-B) that is not quasi-chaotic, results in proportional representation, and promotes the election of moderate candidates. Dummett, M.A.E. [1997. Principles of Electoral Reform. Oxford University, New York] noted quasi-chaos in STV and proposed the “Quota/Borda system” (QBS) as a solution. STV-B and QBS retain proportional representation from STV, permit some influence on candidate selection to occur between voting blocks thereby promoting moderate results, and are much more stable than STV when subjected to small changes in voter preferences. Under STV-B, and not QBS, a minority that shares some preferences may elect a candidate even if the minority is not a solid coalition.

Bitterness suppression with zinc sulfate and na-cyclamate: a model of combined peripheral and central neural approaches to flavor modification

Purpose Zinc sulfate is known to inhibit the bitterness of the antimalarial agent quinine [R. S. J. Keast. The effect of zinc on human taste perception. J. Food Sci. 68:1871–1877 (2003)]. In the present work, we investigated whether zinc sulfate would inhibit other bitter-tasting compounds and pharmaceuticals. The utility of zinc as a general bitterness inhibitor is compromised, however, by the fact that it is also a good sweetness inhibitor [R. S. J. Keast, T. Canty, and P. A. S. Breslin. Oral zinc sulfate solutions inhibit sweet taste perception. Chem. Senses 29:513–521 (2004)] and would interfere with the taste of complex formulations. Yet, zinc sulfate does not inhibit the sweetener Na-cyclamate. Thus, we determined whether a mixture of zinc sulfate and Na-cyclamate would be a particularly effective combination for bitterness inhibition (Zn) and masking (cyclamate).

Method We used human taste psychophysical procedures with chemical solutions to assess bitterness blocking.

Results Zinc sulfate significantly inhibited the bitterness of quinine–HCl, Tetralone, and denatonium benzoate (DB) (p < 0.05), but had no significant effect on the bitterness of sucrose octa-acetate, pseudoephedrine (PSE), and dextromethorphan. A second experiment examined the influence of zinc sulfate on bittersweet mixtures. The bitter compounds were DB and PSE, and the sweeteners were sucrose (inhibited by 25 mM zinc sulfate) and Na-cyclamate (not inhibited by zinc sulfate). The combination of zinc sulfate and Na-cyclamate most effectively inhibited DB bitterness (86%) (p < 0.0016), whereas the mixture's inhibition of PSE bitterness was not different from that of Na-cyclamate alone.

Conclusion A combination of Na-cyclamate and zinc sulfate was most effective at inhibiting bitterness. Thus, the combined use of peripheral oral and central cognitive bitterness reduction strategies should be particularly effective for improving the flavor profile of bitter-tasting foods and pharmaceutical formulations.

Cross-adaptation and bitterness inhibition of L-Tryptophan, L-Phenylalanine and urea : further support for shared peripheral physiology

A previous study investigating individuals' bitterness sensitivities found a close association among three compounds: L-tryptophan (L-trp), L-phenylalanine (L-phe) and urea (Delwiche et al., 2001, Percept. Psychophys. 63, 761-776). In the present experiment, psychophysical cross-adaptation and bitterness inhibition experiments were performed on these three compounds to determine whether the bitterness could be differentially affected by either technique. If the two experimental approaches failed to differentiate L-trp, L-phe and urea's bitterness, then we may infer they share peripheral physiological mechanisms involved in bitter taste. All compounds were intensity matched in each of 13 subjects, so the judgments of adaptation or bitterness inhibition would be based on equal initial magnitudes and, therefore, directly comparable. In the first experiment, cross-adaptation of bitterness between the amino acids was high (>80%) and reciprocal. Urea and quinine-HCl (control) did not cross-adapt with the amino acids symmetrically. In a second experiment, the sodium salts, NaCl and Na gluconate, did not differentially inhibit the bitterness of L-trp, L-phe and urea, but the control compound, MgSO4, was differentially affected. The bitter inhibition experiment supports the hypothesis that L-trp, L-phe and urea share peripheral bitter taste mechanisms, while the adaptation experiment revealed subtle differences between urea and the amino acids indicating that urea and the amino acids activate only partially overlapping bitter taste mechanisms.

c-Cbl-deficient mice have reduced adiposity, higher energy expenditure, and improved peripheral insulin action

Casitas b-lineage lymphoma (c-Cbl) is an E3 ubiquitin ligase that has an important role in regulating the degradation of cell surface receptors. In the present study we have examined the role of c-Cbl in whole-body energy homeostasis. c-Cb^-/- mice exhibited a profound increase in whole-body energy expenditure as determined by increased core temperature and whole-body oxygen consumption. As a consequence, these mice displayed a decrease in adiposity, primarily due to a reduction in cell size despite an increase in food intake. These changes were accompanied by a significant
increase in activity (2- to 3-fold). In addition, cc-Cb-/- mice displayed a marked improvement in whole-body insulin action, primarily due to changes in muscle metabolism. We observed increased protein levels of the insulin receptor (4-fold) and uncoupling protein-3 (2-fold) in skeletal muscle and a significant increase in the phosphorylation of AMP-activated protein kinase and acetyl-CoA carboxylase. These fmdings suggest that c-Cbl plays an integral role in whole-body fuel homeostasis by regulating whole-body energy expenditure and insulin action.

Peripheral insulin resistance develops in transgenic rats overexpressing phosphoenolpyruvate carboxykinase in the kidney

Aims/hypothesis: To study the secondary consequences of impaired suppression of endogenous glucose production (EGP) we have created a transgenic rat overexpressing the gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PEPCK) in the kidney. The aim of this study was to determine whether peripheral insulin resistance develops in these transgenic rats.
Methods: Whole body rate of glucose disappearance (Rd) and endogenous glucose production were measured basally and during a euglycaemic/hyperinsulinaemic clamp in phosphoenolpyruvate carboxykinase transgenic and control rats using [6-3H]-glucose. Glucose uptake into individual tissues was measured in vivo using 2-[1-14C]-deoxyglucose.
Results: Phosphoenolpyruvate carboxykinase transgenic rats were heavier and had increased gonadal and infrarenal fat pad weights. Under basal conditions, endogenous glucose production was similar in phosphoenolpyruvate carboxykinase transgenic and control rats (37.4±1.1 vs 34.6±2.6 µmol/kg/min). Moderate hyperinsulinaemia (810 pmol/l) completely suppressed EGP in control rats (–0.6±5.5 µmol/kg/min, p<0.05) while there was no suppression in phosphoenolpyruvate carboxykinase rats (45.2±7.9 µmol/kg/min). Basal Rd was comparable between PEPCK transgenic and control rats (37.4±1.1 vs 34.6±2.6 µmol/kg/min) but under insulin-stimulated conditions the increase in Rd was greater in control compared to phosphoenolpyruvate carboxykinase transgenic rats indicative of insulin resistance (73.4±11.2 vs 112.0±8.0 µmol/kg/min, p<0.05). Basal glucose uptake was reduced in white and brown adipose tissue, heart and soleus while insulin-stimulated transport was reduced in white and brown adipose tissue, white quadriceps, white gastrocnemius and soleus in phosphoenolpyruvate carboxykinase transgenic compared to control rats. The impairment in both white and brown adipose tissue glucose uptake in phosphoenolpyruvate carboxykinase transgenic rats was associated with a decrease in GLUT4 protein content. In contrast, muscle GLUT4 protein, triglyceride and long-chain acylCoA levels were comparable between PEPCK transgenic and control rats.
Conclusions/interpretation: A primary defect in suppression of EGP caused adipose tissue and muscle insulin resistance.

Routine replacement of short peripheral intravenous cannulae in children: evidence of an unnecessary practice

Short peripheral intravenous cannulae (pIVC) are prone to specific problems such as thrombophlebitis, infiltration and bacterial colonisation. This paper presents data from a study of 80 polyurethane pIVC in 59 children within a general paediatric population. There was no significant colonisation of any cannula by bacterial or fungal organisms. This study provides evidence that it is safe not to routinely replace pIVC in this population. It supports the Centers for Disease Control and Prevention (CDC) guidelines for intravenous cannula (IVC) management in children.

Single transferable vote with Borda elimination : a new vote counting system

Dummett (1997) notes particular difficulties with single transferable vote (STV) and proposes an alternative vote counting system called "Quota/Borda system" (QBS) to remedy specific difficulties. I propose an alternative system, structurally related to QBS, which accomplishes similar solutions but has some significant differences. This alternative system is identical to STV in all aspects except one. It eliminates candidates in reverse order of their Borda scores rather than by their current ranking of first-place votes. I designate this system STV with Borda elimination (STV-B). STV-B and QBS share general features. They retain proportional representation from STV. However, they differ from STV is two critical manners. First, both permit some influence on candidate selection to occur between voting blocks. Second, they are much more stable than STV when subjected to small changes in voter preferences. Outcomes from STV-B differ from QBS outcomes in two ways. Under STV-B, a minority that shares some preferences may elect a candidate even if the minority is not a solid coalition, as is required for minorities under QBS. Further, QBS always selects Borda winners, either for a minority or overall. STV-B may reject a Borda winner through emphasis on each voter's most preferred candidates.

Peripheral quantitative computed tomography in children and adolescents : the 2007 ISCD pediatric official positions

Peripheral quantitative computed tomography (pQCT) has mainly been used as a research tool in children. To evaluate the clinical utility of pQCT and formulate recommendations for its use in children, the International Society
of Clinical Densitometry (ISCD) convened a task force to review the literature and propose areas of consensus and future research. The types of pQCT technology available, the clinical application of pQCT for bone health assessment in children, the important elements to be included in a pQCT report, and quality control monitoring techniques were evaluated. The review revealed a lack of standardization of pQCT techniques, and a paucity of data regarding differences between pQCT manufacturers, models and software versions and their impact in pediatric assessment. Measurement sites varied across studies. Adequate reference data, a critical element for interpretation of pQCT results, were entirely lacking, although some comparative data on healthy children were available. The elements of the
pQCT clinical report and quality control procedures are similar to those recommended for dual-energy X-ray absorptiometry. Future research is needed to establish evidence-based criteria for the selection of the measurement site, scan acquisition and analysis parameters, and outcome measures. Reference data that sufficiently characterize the normal range of variability in the population also need to be established.