Use of dual-grating sensors formed by different types of fiber Bragg gratings for simultaneous temperature and strain measurements

We report on a systematic investigation of the dependence of both temperature and strain sensitivities on the fiber Bragg grating type, including the well-known Type I, Type IIA, and a new type that we have designated Type IA, using both hydrogen-free and hydrogenated B/Ge codoped fibres. We have identified distinct sensitivity characteristics for each grating type, and we have used them to implement a novel dual-grating, dual-parameter sensor device. Three dual-grating sensing schemes with different combinations of grating type have been constructed and compared, and that of a Type IA-Type IIA combination exhibits the best performance, which is also superior to that of previously reported grating-based structures. The characteristics of the measurement errors in such dual-grating sensor systems is also presented in detail. © 2004 Optical Society of America.

Impact of high microwave power on hydrogen impurity trapping in nanocrystalline diamond films grown with simultaneous nitrogen and oxygen addition into methane/hydrogen plasma

In this work, we study for the first time the influence of microwave power higher than 2.0 kW on bonded hydrogen impurity incorporation (form and content) in nanocrystalline diamond (NCD) films grown in a 5 kW MPCVD reactor. The NCD samples of different thickness ranging from 25 to 205 μm were obtained through a small amount of simultaneous nitrogen and oxygen addition into conventional about 4% methane in hydrogen reactants by keeping the other operating parameters in the same range as that typically used for the growth of large-grained polycrystalline diamond films. Specific hydrogen point defect in the NCD films is analyzed by using Fourier-transform infrared (FTIR) spectroscopy. When the other operating parameters are kept constant (mainly the input gases), with increasing of microwave power from 2.0 to 3.2 kW (the pressure was increased slightly in order to stabilize the plasma ball of the same size), which simultaneously resulting in the rise of substrate temperature more than 100 °C, the growth rate of the NCD films increases one order of magnitude from 0.3 to 3.0 μm/h, while the content of hydrogen impurity trapped in the NCD films during the growth process decreases with power. It has also been found that a new H related infrared absorption peak appears at 2834 cm-1 in the NCD films grown with a small amount of nitrogen and oxygen addition at power higher than 2.0 kW and increases with power higher than 3.0 kW. According to these new experimental results, the role of high microwave power on diamond growth and hydrogen impurity incorporation is discussed based on the standard growth mechanism of CVD diamonds using CH4/H2 gas mixtures. Our current experimental findings shed light into the incorporation mechanism of hydrogen impurity in NCD films grown with a small amount of nitrogen and oxygen addition into methane/hydrogen plasma.

A new rapidly absorbed paracetamol tablet containing sodium bicarbonate. II. Dissolution studies and in vitro/in vivo correlation

The objective of this study was to compare the in vitro dissolution profile of a new rapidly absorbed paracetamol tablet containing sodium bicarbonate (PS) with that of a conventional paracetamol tablet (P), and to relate these by deconvolution and mapping to in vivo release. The dissolution methods used include the standard procedure described in the USP monograph for paracetamol tablets, employing buffer at pH5.8 or 0.05 M HCl at stirrer speeds between 10 and 50 rpm. The mapping process was developed and implemented in Microsoft Excel® worksheets that iteratively calculated the optimal values of scale and shape factors which linked in vivo time to in vitro time. The in vitro-in vivo correlation (IVIVC) was carried out simultaneously for both formulations to produce common mapping factors. The USP method, using buffer at pH5.8, demonstrated no difference between the two products. However, using an acidic medium the rate of dissolution of P but not of PS decreased with decreasing stirrer speed. A significant correlation (r=0.773; p<.00001) was established between in vivo release and in vitro dissolution using the profiles obtained with 0.05 M HCl and a stirrer speed of 30 rpm. The scale factor for optimal simultaneous IVIVC in the fasting state was 2.54 and the shape factor was 0.16; corresponding values for mapping in the fed state were 3.37 and 0.13 (implying a larger in vitro-in vivo time difference but reduced shape difference in the fed state). The current IVIVC explains, in part, the observed in vivo variability of the two products. The approach to mapping may also be extended to different batches of these products, to predict the impact of any changes of in vitro dissolution on in vivo release and plasma drug concentration-time profiles.

Simultaneous refractive index and temperature measurement using cascaded long-period grating in double-cladding fibre

A compact scheme for simultaneous temperature and surrounding refractive index (SRI) measurement using two long-period gratings (LPGs) of different periods inscribed side-by-side in a single piece of a double-cladding fibre is presented. One of the LPGs is sensitive to both SRI and temperature, whilst the second is sensitive to temperature only.

Simultaneous refractive index and temperature measurement using a cascaded long-period grating device

We present a compact scheme for simultaneous temperature and surrounding refractive index (SRI) measurement using two long period gratings (LPGs) of different periods inscribed side-by-side in a single piece of a double-cladding fibre. One of the LPGs is sensitive to both SRI and temperature changes whilst the second is SRI-insensitive but shows spectral shift with temperature changes. In addition, we show that a resonance peak of the SRI-insensitive LPG can be designed to appear in the EDFA wavelength region with potential use for gain flattening applications.

Simultaneous refractive index and temperature measurement using cascaded long-period grating in double-cladding fibre

A compact scheme for simultaneous temperature and surrounding refractive index (SRI) measurement using two long-period gratings (LPGs) of different periods inscribed side-by-side in a single piece of a double-cladding fibre is presented. One of the LPGs is sensitive to both SRI and temperature, whilst the second is sensitive to temperature only.

Simultaneous refractive index and temperature measurement using a cascaded long-period grating device

We present a compact scheme for simultaneous temperature and surrounding refractive index (SRI) measurement using two long period gratings (LPGs) of different periods inscribed side-by-side in a single piece of a double-cladding fibre. One of the LPGs is sensitive to both SRI and temperature changes whilst the second is SRI-insensitive but shows spectral shift with temperature changes. In addition, we show that a resonance peak of the SRI-insensitive LPG can be designed to appear in the EDFA wavelength region with potential use for gain flattening applications.

Mutations of beta-arrestin 2 that limit self-association also interfere with interactions with the beta2-adrenoceptor and the ERK1/2 MAPKs:implications for beta2-adrenoceptor signalling via the ERK1/2 MAPKs

FRET (fluorescence resonance energy transfer) and co-immunoprecipitation studies confirmed the capacity of beta-arrestin 2 to self-associate. Amino acids potentially involved in direct protein-protein interaction were identified via combinations of spot-immobilized peptide arrays and mapping of surface exposure. Among potential key amino acids, Lys(285), Arg(286) and Lys(295) are part of a continuous surface epitope located in the polar core between the N- and C-terminal domains. Introduction of K285A/R286A mutations into beta-arrestin 2-eCFP (where eCFP is enhanced cyan fluorescent protein) and beta-arrestin 2-eYFP (where eYFP is enhanced yellow fluorescent protein) constructs substantially reduced FRET, whereas introduction of a K295A mutation had a more limited effect. Neither of these mutants was able to promote beta2-adrenoceptor-mediated phosphorylation of the ERK1/2 (extracellular-signal-regulated kinase 1/2) MAPKs (mitogen-activated protein kinases). Both beta-arrestin 2 mutants displayed limited capacity to co-immunoprecipitate ERK1/2 and further spot-immobilized peptide arrays indicated each of Lys(285), Arg(286) and particularly Lys(295) to be important for this interaction. Direct interactions between beta-arrestin 2 and the beta2-adrenoceptor were also compromised by both K285A/R286A and K295A mutations of beta-arrestin 2. These were not non-specific effects linked to improper folding of beta-arrestin 2 as limited proteolysis was unable to distinguish the K285A/R286A or K295A mutants from wild-type beta-arrestin 2, and the interaction of beta-arrestin 2 with JNK3 (c-Jun N-terminal kinase 3) was unaffected by the K285A/R286A or L295A mutations. These results suggest that amino acids important for self-association of beta-arrestin 2 also play an important role in the interaction with both the beta2-adrenoceptor and the ERK1/2 MAPKs. Regulation of beta-arrestin 2 self-association may therefore control beta-arrestin 2-mediated beta2-adrenoceptor-ERK1/2 MAPK signalling.

Comparison of near visual acuity and reading metrics in presbyopia correction

PURPOSE: To provide a consistent standard for the evaluation of different types of presbyopic correction. SETTING: Eye Clinic, School of Life and Health Sciences, Aston University, Birmingham, United Kingdom. METHODS: Presbyopic corrections examined were accommodating intraocular lenses (IOLs), simultaneous multifocal and monovision contact lenses, and varifocal spectacles. Binocular near visual acuity measured with different optotypes (uppercase letters, lowercase letters, and words) and reading metrics assessed with the Minnesota Near Reading chart (reading acuity, critical print size [CPS], CPS reading speed) were intercorrelated (Pearson product moment correlations) and assessed for concordance (intraclass correlation coefficients [ICC]) and agreement (Bland-Altman analysis) for indication of clinical usefulness. RESULTS: Nineteen accommodating IOL cases, 40 simultaneous contact lens cases, and 38 varifocal spectacle cases were evaluated. Other than CPS reading speed, all near visual acuity and reading metrics correlated well with each other (r>0.70, P<.001). Near visual acuity measured with uppercase letters was highly concordant (ICC, 0.78) and in close agreement with lowercase letters (+/- 0.17 logMAR). Near word acuity agreed well with reading acuity (+/- 0.16 logMAR), which in turn agreed well with near visual acuity measured with uppercase letters 0.16 logMAR). Concordance (ICC, 0.18 to 0.46) and agreement (+/- 0.24 to 0.30 logMAR) of CPS with the other near metrics was moderate. CONCLUSION: Measurement of near visual ability in presbyopia should be standardized to include assessment of near visual acuity with logMAR uppercase-letter optotypes, smallest logMAR print size that maintains maximum reading speed (CPS), and reading speed. J Cataract Refract Surg 2009; 35:1401-1409 (C) 2009 ASCRS and ESCRS

Protein oxidation:role in signalling and detection by mass spectrometry

Proteins can undergo a wide variety of oxidative post-translational modifications (oxPTM); while reversible modifications are thought to be relevant in physiological processes, non-reversible oxPTM may contribute to pathological situations and disease. The oxidant is also important in determining the type of oxPTM, such as oxidation, chlorination or nitration. The best characterized oxPTMs involved in signalling modulation are partial oxidations of cysteine to disulfide, glutathionylated or sulfenic acid forms that can be reversed by thiol reductants. Proline hydroxylation in HIF signalling is also quite well characterized, and there is increasing evidence that specific oxidations of methionine and tyrosine may have some biological roles. For some proteins regulated by cysteine oxidation, the residues and molecular mechanism involved have been extensively studied and are well understood, such as the protein tyrosine phosphatase PTP1B and MAP3 kinase ASK1, as well as transcription factor complex Keap1-Nrf2. The advances in understanding of the role oxPTMs in signalling have been facilitated by advances in analytical technology, in particular tandem mass spectrometry techniques. Combinations of peptide sequencing by collisionally induced dissociation and precursor ion scanning or neutral loss to select for specific oxPTMs have proved very useful for identifying oxidatively modified proteins and mapping the sites of oxidation. The development of specific labelling and enrichment procedures for S-nitrosylation or disulfide formation has proved invaluable, and there is ongoing work to establish analogous methods for detection of nitrotyrosine and other modifications.

Bioreaction and separation in batch chromatographic columns

The objective of this work has been to study the behaviour and performance of a batch chromatographic column under simultaneous bioreaction and separation conditions for several carbohydrate feedstocks. Four bioreactions were chosen, namely the hydrolysis of sucrose to glucose and fructose using the enzyme invertase, the hydrolysis of inulin to fructose and glucose using inulinase, the hydrolysis of lactose to glucose and galactose using lactase and the isomerization of glucose to fructose using glucose isomerase. The chromatographic columns employed were jacketed glass columns ranging from 1 m to 2 m long and the internal diameter ranging from 0.97 cm to 1.97 cm. The stationary phase used was a cation exchange resin (PUROLITE PCR-833) in the Ca2+ form for the hydrolysis and the Mg2+ form for the isomerization reactions. The mobile phase used was a diluted enzyme solution which was continuously pumped through the chromatographic bed. The substrate was injected at the top of the bed as a pulse. The effect of the parameters pulse size, the amount of substrate solution introduced into the system corresponding to a percentage of the total empty column volume (% TECV), pulse concentration, eluent flowrate and the enzyme activity of the eluent were investigated. For the system sucrose-invertase complete conversions of substrate were achieved for pulse sizes and pulse concentrations of up to 20% TECV and 60% w/v, respectively. Products with purity above 90% were obtained. The enzyme consumption was 45% of the amount theoretically required to produce the same amount of product as in a conventional batch reactor. A value of 27 kg sucrose/m3 resin/h for the throughput of the system was achieved. The systematic investigation of the factors affecting the performance of the batch chromatographic bioreactor-separator was carried out by employing a factorial experimental procedure. The main factors affecting the performance of the system were the flowrate and enzyme activity. For the system inulin-inulinase total conversions were also obtained for pulses sizes of up to 20 % TECV and a pulse concentration of 10 % w/v. Fructose rich fractions with 100 % purity and representing up to 99.4 % of the total fructose generated were obtained with an enzyme consumption of 32 % of the amount theoretically required to produce the same amount of product in a conventional batch reactor. The hydrolysis of lactose by lactase was studied in the glass columns and also in an SCCR-S unit adapted for batch operation, in co-operation with Dr. Shieh, a fellow researcher in the Chemical Engineering and Applied Chemistry Department at Aston University. By operating at up to 30 % w/v lactose feed concentrations complete conversions were obtained and the purities of the products generated were above 90%. An enzyme consumption of 48 % of the amount theoretically required to produce the same amount of product in a conventional batch reactor was achieved. On working with the system glucose-glucose isomerase, which is a reversible reaction, the separation obtained with the stationary phase conditioned in the magnesium form was very poor although the conversion obtained was compatible with those for conventional batch reactors. By working with a mixed pulse of enzyme and substrate, up to 82.5 % of the fructose generated with a purity of 100 % was obtained. The mathematical modelling and computer simulation of the batch chromatographic bioreaction-separation has been performed on a personal computer. A finite difference method was used to solve the partial differential equations and the simulation results showed good agreement with the experimental results.

Biosynthesis and separation of dextran fructose mixtures in a chromatographic reactor

A literature review of work carried out on batch and continuous chromatographic biochemical reactor-separators has been made. The major part of this work has involved the development of a batch chromatographic reactor-separator for the production of dextran and fructose by the enzymatic action of the enzyme dextransucrase on sucrose. In this reactor, simultaneous reaction and separation occurs thus reducing downstream processing and isolation of products as compared to the existing industrial process. The chromatographic reactor consisted of a glass column packed with a stationary phase consisting of cross linked polysytrene resin in the calcium form. The mobile phase consisted of diluted dextransucrase in deionised water. Initial experiments were carried out on a reactor separtor which had an internal diameter of 0.97cm and length of 1.5m. To study the effect of scale up the reactor diameter was doubled to 1.94cm and length increased to 1.75m. The results have shown that the chromatographic reactor uses more enzyme than a conventional batch reactor for a given conversion of sucrose and that an increase in void volume results in higher conversions of sucrose. A comparison of the molecular weight distribution of dextran produced by the chromatographic reactor was made with that from a conventional batch reactor. The results have shown that the chromatographic reactor produces 30% more dextran of molecular weight greater than 150,000 daltons at 20% w/v sucrose concentration than conventional reactors. This is because some of the fructose molecules are prevented as acting as acceptors in the chromatographic reactor due to their removal from the reaction zone. In the conventional reactor this is not possible and therefore a greater proportion of low molecular weight dextran is produced which does not have much clinical use. A theoretical model was developed to describe the behaviour of the reactor separator and this model was simulated using a computer. The simulation predictions showed good agreement with experimental results at high eluent flowrates and low conversions.

Strategy making process, its content and context in small professional football clubs

This thesis examines the phenomenon of strategy. Making as practised by small professional football clubs. The study was undertaken because football clubs were perceived to have problems with strategy-making and because it was believed that the specific circumstances of football clubs could be outside the range of views covered by conventional views of strategy-making. The characteristics of the club environment are its uncertainty and unpredictability, simultaneous competition and co--operation, strong regulations, and a not-for-profit orientation. Small clubs in particular face a constant struggle for financial viability and survival, due in part to split business and playing objectives. The study was designed to establish the extent and nature of the difficulties clubs experience with a view to preparing the way for creating practical guidance on ways to overcome them. Clearly, in order to survive in the long term, small professional football clubs require very effective strategic decisions. This study has addressed this issue by inquiring into the nature of strategy making for these organisations with the objective to establish the general direction in which the football clubs in question should be moving. As a result, the main research question to guide this investigation was determined as: Why do small professional football clubs have difficulties making strategies. The investigation was based on an analysis the concept of strategy and its elements, the strategic vision and objectives, the process by which strategic action comes about, the strategic action itself, and the context within which this action occurs. Data has been collected, analysed and interpreted in relation to each of these elements. Together with a wide variety of published material, 20 small football clubs have been sampled and personal interviews were conducted with board members of those clubs. The findings indicate that small football clubs do indeed experience considerable difficulties in making strategies, the reasons for which lie both in the characteristics of their competitive environment and their approaches to strategy-making. The competitive environment is characterised by a cartel-like structure with a high degree of regulation, high levels of uncertainty, little control over the core product or the production process, short-term business cycles and a close geographical link between a club with its local market. The management of clubs is characterised by the need to balance conflicting sporting and business objectives. Formal planning techniques are of little use in the small football club context as decision-making processes have a strong political character and the development of novel strategies is hindered by a strong conservative, industry paradigm and a lack of financial and managerial resources. It is concluded that there is no simple advice to be given to clubs, as they must re-examine the relationship between their playing and business objectives to create a unified and workable approach.

The retrograde delivery of adenovirus vector carrying the gene for brain-derived neurotrophic factor protects neurons and oligodendrocytes from apoptosis in the chronically compressed spinal cord of twy/twy mice

STUDY DESIGN: The twy/twy mouse undergoes spontaneous chronic mechanical compression of the spinal cord; this in vivo model system was used to examine the effects of retrograde adenovirus (adenoviral vector [AdV])-mediated brain-derived neurotrophic factor (BDNF) gene delivery to spinal neural cells. OBJECTIVE: To investigate the targeting and potential neuroprotective effect of retrograde AdV-mediated BDNF gene transfection in the chronically compressed spinal cord in terms of prevention of apoptosis of neurons and oligodendrocytes. SUMMARY OF BACKGROUND DATA: Several studies have investigated the neuroprotective effects of neurotrophins, including BDNF, in spinal cord injury. However, no report has described the effects of retrograde neurotrophic factor gene delivery in compressed spinal cords, including gene targeting and the potential to prevent neural cell apoptosis. METHODS: AdV-BDNF or AdV-LacZ (as a control gene) was injected into the bilateral sternomastoid muscles of 18-week old twy/twy mice for retrograde gene delivery via the spinal accessory motor neurons. Heterozygous Institute of Cancer Research mice (+/twy), which do not undergo spontaneous spinal compression, were used as a control for the effects of such compression on gene delivery. The localization and cell specificity of ß-galactosidase expression (produced by LacZ gene transfection) and BDNF expression in the spinal cord were examined by coimmunofluorescence staining for neural cell markers (NeuN, neurons; reactive immunology protein, oligodendrocytes; glial fibrillary acidic protein, astrocytes; OX-42, microglia) 4 weeks after gene injection. The possible neuroprotection afforded by retrograde AdV-BDNF gene delivery versus AdV-LacZ-transfected control mice was assessed by scoring the prevalence of apoptotic cells (terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling-positive cells) and immunoreactivity to active caspases -3, -8, and -9, p75, neurofilament 200 kD (NF), and for the oligodendroglial progenitor marker, NG2. RESULTS.: Four weeks after injection, the retrograde delivery of the LacZ marker gene was identified in cervical spinal neurons and some glial cells, including oligodendrocytes in the white matter of the spinal cord, in both the twy/twy mouse and the heterozygous Institute of Cancer Research mouse (+/twy). In the compressed spinal cord of twy/twy mouse, AdV-BDNF gene transfection resulted in a significant decrease in the number of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling-positive cells present in the spinal cord and a downregulation in the caspase apoptotic pathway compared with AdV-LacZ (control) gene transfection. There was a marked and significant increase in the areas of the spinal cord of AdV-BDNF-injected mice that were NF- and NG2-immunopositive compared with AdV-LacZ-injected mice, indicating the increased presence of neurons and oligodendrocytes in response to BDNF transfection. CONCLUSION: Our results demonstrate that targeted retrograde BDNF gene delivery suppresses apoptosis in neurons and oligodendrocytes in the chronically compressed spinal cord of twy/twy mouse. Further work is required to establish whether this method of gene delivery may provide neuroprotective effects in other situations of compressive spinal cord injury.

Mass transfer and chemical reaction on a distillation plate

A multistage distillation column in which mass transfer and a reversible chemical reaction occurred simultaneously, has been investigated to formulate a technique by which this process can be analysed or predicted. A transesterification reaction between ethyl alcohol and butyl acetate, catalysed by concentrated sulphuric acid, was selected for the investigation and all the components were analysed on a gas liquid chromatograph. The transesterification reaction kinetics have been studied in a batch reactor for catalyst concentrations of 0.1 - 1.0 weight percent and temperatures between 21.4 and 85.0 °C. The reaction was found to be second order and dependent on the catalyst concentration at a given temperature. The vapour liquid equilibrium data for six binary, four ternary and one quaternary systems are measured at atmospheric pressure using a modified Cathala dynamic equilibrium still. The systems with the exception of ethyl alcohol - butyl alcohol mixtures, were found to be non-ideal. Multicomponent vapour liquid equilibrium compositions were predicted by a computer programme which utilised the Van Laar constants obtained from the binary data sets. Good agreement was obtained between the predicted and experimental quaternary equilibrium vapour compositions. Continuous transesterification experiments were carried out in a six stage sieve plate distillation column. The column was 3" in internal diameter and of unit construction in glass. The plates were 8" apart and had a free area of 7.7%. Both the liquid and vapour streams were analysed. The component conversion was dependent on the boilup rate and the reflux ratio. Because of the presence of the reaction, the concentration of one of the lighter components increased below the feed plate. In the same region a highly developed foam was formed due to the presence of the catalyst. The experimental results were analysed by the solution of a series of simultaneous enthalpy and mass equations. Good agreement was obtained between the experimental and calculated results.