Synthesis and modification of Alumina nanofibres and its applications

This thesis is a forward study of alumina nanofiber material in developing its applications biology field. It demonstrates that by applying proper modification strategy, alumina nanofiber is a promising material in protein purification and enzyme immobilization. The hydrophobic modification has dramatically improved the rejecting of protein molecular in purification system. On the other hand, utilisation of cross-linking agent firmly combined alumina nanofiber and target enzyme for immobilisation purpose. This step of progress could lead to inspiration of alumina nanofiber’s application in various area.

SERS based detection of barcoded gold nanoparticle assemblies from within animal tissue

We have explored the potential of deep Raman spectroscopy, specifically surface enhanced spatially offset Raman spectroscopy (SESORS), for non-invasive detection from within animal tissue, by employing SERS-barcoded nanoparticle (NP) assemblies as the diagnostic agent. This concept has been experimentally verified in a clinic-relevant backscattered Raman system with an excitation line of 785 nm under ex vivo conditions. We have shown that our SORS system, with a fixed offset of 2-3 mm, offered sensitive probing of injected QTH-barcoded NP assemblies through animal tissue containing both protein and lipid. In comparison to that of non-aggregated SERS-barcoded gold NPs, we have demonstrated that the tailored SERS-barcoded aggregated NP assemblies have significantly higher detection sensitivity. We report that these NP assemblies can be readily detected at depths of 7-8 mm from within animal proteinaceous tissue with high signal-to-noise (S/N) ratio. In addition they could also be detected from beneath 1-2 mm of animal tissue with high lipid content, which generally poses a challenge due to high absorption of lipids in the near-infrared region. We have also shown that the signal intensity and S/N ratio at a particular depth is a function of the SERS tag concentration used and that our SORS system has a QTH detection limit of 10-6 M. Higher detection depths may possibly be obtained with optimization of the NP assemblies, along with improvements in the instrumentation. Such NP assemblies offer prospects for in vivo, non-invasive detection of tumours along with scope for incorporation of drugs and their targeted and controlled release at tumour sites. These diagnostic agents combined with drug delivery systems could serve as a “theranostic agent”, an integration of diagnostics and therapeutics into a single platform.

GEF-H1-RhoA signaling pathway mediates LPS-induced NF-κB transactivation and IL-8 synthesis in endothelial cells

Secretion of proinflammatory cytokines by LPS activated endothelial cells contributes substantially to the pathogenesis of sepsis. However, the mechanism involved in this process is not well understood. In the present study, we determined the roles of GEF-H1 (Guanine-nucleotide exchange factor-H1)-RhoA signalling in LPS-induced interleukin-8 (IL-8, CXCL8) production in endothelial cells. First, we observed that GEF-H1 expression was upregulated in a dose- and time-dependent manner as consistent with TLR4 (Toll-like receptor 4) expression after LPS stimulation. Afterwards, Clostridium difficile toxin B-10463 (TcdB-10463), an inhibitor of Rho activities, reduced LPS-induced NF-κB phosphorylation. Inhibition of GEF-H1 and RhoA expression reduced LPS-induced NF-κB and p38 phosphorylation. TLR4 knockout blocked LPS-induced activity of RhoA, however, MyD88 knockout did not impair the LPS-induced activity of RhoA. Nevertheless, TLR4 and MyD88 knockout both significantly inhibited transactivation of NF-κB. GEF-H1-RhoA and MyD88 both induced significant changes in NF-κB transactivation and IL-8 synthesis. Co-inhibition of GEF-H1-RhoA and p38 expression produced similar inhibitory effects on LPS-induced NF-κB transactivation and IL-8 synthesis as inhibition of p38 expression alone, thus confirming that activation of p38 was essential for the GEF-H1-RhoA signalling pathway to induce NF-κB transactivation and IL-8 synthesis. Taken together, these results demonstrate that LPS-induced NF-κB activation and IL-8 synthesis in endothelial cells are regulated by the MyD88 pathway and GEF-H1-RhoA pathway.

Three-phase model of consumers' behaviours : a synthesis of the theory of planned behaviour, self-determination theory and planning

Using a longitudinal study, an overall behavioural model with three related phases (cognitive, motivational and volitional phase) across three studies was examined to identify the factors that most prominently drive consumer environmental behaviour. This thesis provides empirical evidence to support the behavioural model in an environmental consumption context and shows a new avenue for promoting consumer environmental behaviour.

Synthesis, characterisation and application of organic surfactants modified clays for water purification

This thesis offered a step forward in the development of cheap and effective materials for water treatment. It described the modification of naturally abundant clay minerals with organic molecules, and used the modified clays as effective adsorbents for the removal of recalcitrant organic water pollutants. The outcome of the study greatly extended our understanding of the synthesis and characteristic properties of clay and modified clay minerals, provided optimistic evaluation of the modified clays for environmental remediation and offered potential utility for clay minerals in the industry and environment.

Supported gold nanoparticles as photocatalysts utilising the full solar spectrum for organic synthesis

This thesis is an innovative study for organic synthesis using supported gold nanoparticles as photocatalysts under visible light irradiation. It especially examines a novel green process for efficient hydroamination of alkynes with amines. The investigation of other traditional reduction and oxidation reactions also adds significantly to the knowledge of gold nanoparticles and titania nanofibres as photocatalysts for organic synthesis.

Controlled synthesis of inorganic semiconductor nanocrystals and their applications

This thesis is a comprehensive study of the synthesis of nanomaterials. It explores the synthetic methods on the control of the size, shape and phase of semiconductor nanocrystals. A number of important conclusions, including the mechanism behind crystal growth and the structure-relationship, have been drawn through the experimental and theoretical investigation. The synthesized nanocrystals have been tested for applications in gas sensing, photocatalysis and solar cells, which exhibit considerable commercialization potential.

Synthesis and evaluation of resveratrol-based nitroxides as potential treatments for hypertension

The synthesis and evaluation of novel resveratrol-based nitroxides have been explored for the potential treatment of hypertension. New methodology for the direct aryl iodination of isoindoline and isoindoline nitroxide using periodic acid and potassium iodide in concentrated sulphuric acid was developed. Diiodinated tetramethyl and tetraethyl isoindolines and a tetramethyl isoindoline nitroxide were prepared in excellent yields (70 – 82%). A diiodinated tetraethyl isoindoline nitroxide was generated from the corresponding nitroxide in modest yield (37%) alongside iodinated nitrones. The mono-iodinated species were also generated in modest yields (34 – 48%). Incorporation of the nitroxide unit into the structure of resveratrol was achieved using palladium-catalysed Heck coupling. Use of the previously prepared iodo products 5-iodo-1,1,3,3-tetramethylisoindolin-2-yloyl 18 and 5,6-diiodo-1,1,3,3-tetramethylisoindolin-2-yloyl 22 gave resveratrol nitroxides 12 and 13 in yields of 50% (optimized) and 1.6% respectively. Preliminary evaluation of the resveratrol analogue 12 as a treatment for hypertension was undertaken in the DOCA-salt rat model. A reduction in systolic blood pressure as well as alleviation of ventricular hypertrophy was observed. A larger study involving the DOCA salt rats is currently in progress.

Production of metal oxide nanoparticles

Particles having at least regions of at least one metal oxide having nano-sized grains are produced by providing particles of a material having an initial, nonequiaxed particle shape, prepg. a mixt. of these particles and at last one metal oxide precursor, and treating the mixt. such that the precursor reacts with the particles. The process can be a co-pptn. process, sol-gel synthesis, micro-emulsion method, surfactant-based process, or a process that uses polymers. Complex metal oxide nanoparticles are produced by (a) prepg. a soln. contg. metal cations, (b) mixing the soln. with a surfactant to form micelles within the soln., and (c) heating the micellar liq. to form metal oxide and to remove the surfactant. The formed metal oxide particles have essentially the same morphol. (particle size and shape) as the initial morphol. of the material particles provided. [on SciFinder(R)]

Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis

Quantity and timing of protein ingestion are major factors regulating myofibrillar protein synthesis (MPS). However, the effect of specific ingestion patterns on MPS throughout a 12 h period is unknown. We determined how different distributions of protein feeding during 12 h recovery after resistance exercise affects anabolic responses in skeletal muscle. Twenty-four healthy trained males were assigned to three groups (n = 8/group) and undertook a bout of resistance exercise followed by ingestion of 80 g of whey protein throughout 12 h recovery in one of the following protocols: 8 × 10 g every 1.5 h (PULSE); 4 × 20 g every 3 h (intermediate: INT); or 2 × 40 g every 6 h (BOLUS). Muscle biopsies were obtained at rest and after 1, 4, 6, 7 and 12 h post exercise. Resting and post-exercise MPS (l-[ring-(13)C6] phenylalanine), and muscle mRNA abundance and cell signalling were assessed. All ingestion protocols increased MPS above rest throughout 1-12 h recovery (88-148%, P < 0.02), but INT elicited greater MPS than PULSE and BOLUS (31-48%, P < 0.02). In general signalling showed a BOLUS>INT>PULSE hierarchy in magnitude of phosphorylation. MuRF-1 and SLC38A2 mRNA were differentially expressed with BOLUS. In conclusion, 20 g of whey protein consumed every 3 h was superior to either PULSE or BOLUS feeding patterns for stimulating MPS throughout the day. This study provides novel information on the effect of modulating the distribution of protein intake on anabolic responses in skeletal muscle and has the potential to maximize outcomes of resistance training for attaining peak muscle mass.

Preexercise aminoacidemia and muscle protein synthesis after resistance exercise

PURPOSE We have previously shown that the aminoacidemia caused by the consumption of a rapidly digested protein after resistance exercise enhances muscle protein synthesis (MPS) more than the amino acid (AA) profile associated with a slowly digested protein. Here, we investigated whether differential feeding patterns of a whey protein mixture commencing before exercise affect postexercise intracellular signaling and MPS. METHODS Twelve resistance-trained males performed leg resistance exercise 45 min after commencing each of three volume-matched nutrition protocols: placebo (PLAC, artificially sweetened water), BOLUS (25 g of whey protein + 5 g of leucine dissolved in artificially sweetened water; 1× 500 mL), or PULSE (15× 33-mL aliquots of BOLUS drink every 15 min). RESULTS The preexercise rise in plasma AA concentration with PULSE was attenuated compared with BOLUS (P < 0.05); this effect was reversed after exercise, with two-fold greater leucine concentrations in PULSE compared with BOLUS (P < 0.05). One-hour postexercise, phosphorylation of p70 S6K and rpS6 was increased above baseline with BOLUS and PULSE, but not PLAC (P < 0.05); furthermore, PULSE > BOLUS (P < 0.05). MPS throughout 5 h of recovery was higher with protein ingestion compared with PLAC (0.037 ± 0.007), with no differences between BOLUS or PULSE (0.085 ± 0.013 vs. 0.095 ± 0.010%•h, respectively, P = 0.56). CONCLUSIONS Manipulation of aminoacidemia before resistance exercise via different patterns of intake of protein altered plasma AA profiles and postexercise intracellular signaling. However, there was no difference in the enhancement of the muscle protein synthetic response after exercise. Protein sources producing a slow AA release, when consumed before resistance exercise in sufficient amounts, are as effective as rapidly digested proteins in promoting postexercise MPS.

Sex-based comparisons of myofibrillar protein synthesis after resistance exercise in the fed state

Sex-based comparisons of myofibrillar protein synthesis after resistance exercise in the fed state. J Appl Physiol 112: 1805-1813, 2012. First published March 1, 2012; doi:10.1152/japplphysiol.00170.2012.- We made sex-based comparisons of rates of myofibrillar protein synthesis (MPS) and anabolic signaling after a single bout of high-intensity resistance exercise. Eight men (20 ± 10 yr, BMI = 24.3 ± 2.4) and eight women (22 ± 1.8 yr, BMI = 23.0 ± 1.9) underwent primed constant infusions of L-[ring-13C6]phenylalanine on consecutive days with serial muscle biopsies. Biopsies were taken from the vastus lateralis at rest and 1, 3, 5, 24, 26, and 28 h after exercise. Twenty-five grams of whey protein was ingested immediately and 26 h after exercise. We also measured exercise-induced serum testosterone because it is purported to contribute to increases in myofibrillar protein synthesis (MPS) postexercise and its absence has been hypothesized to attenuate adaptative responses to resistance exercise in women. The exercise-induced area under the testosterone curve was 45-fold greater in men than women in the early (1 h) recovery period following exercise (P < 0.001). MPS was elevated similarly in men and women (2.3- and 2.7-fold, respectively) 1-5 h postexercise and after protein ingestion following 24 h recovery. Phosphorylation of mTORSer2448 was elevated to a greater extent in men than women acutely after exercise (P = 0.003), whereas increased phosphorylation of p70S6K1Thr389 was not different between sexes. Androgen receptor content was greater in men (main effect for sex, P = 0.049). Atrogin-1 mRNA abundance was decreased after 5 h recovery in both men and women (P < 0.001), and MuRF-1 expression was elevated in men after protein ingestion following 24 h recovery (P = 0.003). These results demonstrate minor sex-based differences in signaling responses and no difference in the MPS response to resistance exercise in the fed state. Interestingly, our data demonstrate that exerciseinduced increases in MPS are dissociated from postexercise testosteronemia and that stimulation of MPS occurs effectively with low systemic testosterone concentrations in women.

Rapid aminoacidemia enhances myofibrillar protein synthesis and anabolic intramuscular signaling responses after resistance exercise

Background: Ingestion of whey or casein yields divergent patterns of aminoacidemia that influence whole-body and skeletal muscle myofibrillar protein synthesis (MPS) after exercise. Direct comparisons of the effects of contrasting absorption rates exhibited by these proteins are confounded by their differing amino acid contents. Objective: Our objective was to determine the effect of divergent aminoacidemia by manipulating ingestion patterns of whey protein alone on MPS and anabolic signaling after resistance exercise. Design: In separate trials, 8 healthy men consumed whey protein either as a single bolus (BOLUS; 25-g dose) or as repeated, small, "pulsed" drinks (PULSE; ten 2.5-g drinks every 20 min) to mimic a more slowly digested protein. MPS and phosphorylation of signaling proteins involved in protein synthesis were measured at rest and after resistance exercise. Results: BOLUS increased blood essential amino acid (EAA) concentrations above those of PULSE (162% compared with 53%, P < 0.001) 60 min after exercise, whereas PULSE resulted in a smaller but sustained increase in aminoacidemia that remained elevated above BOLUS amounts later (180-220 min after exercise, P < 0.05). Despite an identical net area under the EAA curve, MPS was elevated to a greater extent after BOLUS than after PULSE early (1-3 h: 95% compared with 42%) and later (3-5 h: 193% compared with 121%) (both P < 0.05). There were greater changes in the phosphorylation of the Akt-mammalian target of rapamycin pathway after BOLUS than after PULSE. Conclusions: Rapid aminoacidemia in the postexercise period enhances MPS and anabolic signaling to a greater extent than an identical amount of protein fed in small pulses that mimic a more slowly digested protein. A pronounced peak aminoacidemia after exercise enhances protein synthesis.

Nutrient provision increases signalling and protein synthesis in human skeletal muscle after repeated sprints

The effect of nutrient availability on the acute molecular responses following repeated sprint exercise is unknown. The aim of this study was to determine skeletal muscle cellular and protein synthetic responses following repeated sprint exercise with nutrient provision. Eight healthy young male subjects undertook two sprint cycling sessions (10 × 6 s, 0.75 N m torque kg -1, 54 s recovery) with either pre-exercise nutrient (24 g whey, 4.8 g leucine, 50 g maltodextrin) or non-caloric placebo ingestion. Muscle biopsies were taken from vastus lateralis at rest, and after 15 and 240 min post-exercise recovery to determine muscle cell signalling responses and protein synthesis by primed constant infusion of L-[ring- 13C 6] phenylalanine. Peak and mean power outputs were similar between nutrient and placebo trials. Post-exercise myofibrillar protein synthetic rate was greater with nutrient ingestion compared with placebo ( ? 48%, P<0.05) but the rate of mitochondrial protein synthesis was similar between treatments. The increased myofibrillar protein synthesis following sprints with nutrient ingestion was associated with coordinated increases in Akt-mTOR-S6KrpS6 phosphorylation 15 min post-exercise (?200-600%, P<0.05), while there was no effect on these signalling molecules when exercise was undertaken in the fasted state. For the first time we report a beneficial effect of nutrient provision on anabolic signalling and muscle myofibrillar protein synthesis following repeated sprint exercise. Ingestion of protein/carbohydrate in close proximity to high-intensity sprint exercise provides an environment that increases cell signalling and protein synthesis.

Fabrication and electrocatalytic properties of polyaniline/Pt nanoparticle composites

Polyaniline (PANI)/Pt nanoparticle composites can be prepared by the spontaneous redox reaction of K2PtCl4 with PANI, to yield thin films that show electrocatalytic properties in both acidic and neutral aqueous media.