6 resultados para Non contact measurement

em Brock University, Canada


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Whiplash injuries are common yet enigmatic to substantiate clinically. Trigeminal somatosensory evoked potentials (TSEPs) were posited as an indicator of trigeminal nerve conduction damage resulting from whiplash. Alternating polarity square-wave current stimuli were applied transcutaneously in the facial region. 379 recorded pilot trials from 27 participants (8 male and 19 female) were utilized to develop a non-invasive recording capability for TSEPs. Stimulus intensity and artifact, cortical recording sites, stimulation electrode design and placement were explored. Statistically significant differences in amplitude of TSEP waveform components at 13, 19 and 27 ms between uninjured and whiplashed participants were noted. Increased stimulus intensity in whiplashed participants was observed to increase TSEP amplitude. The present methodology and hardware are discussed and directions for future advancement of the current process are outlined.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Infrared thermography is a non-invasive technique that measures mid to long-wave infrared radiation emanating from all objects and converts this to temperature. As an imaging technique, the value of modern infrared thermography is its ability to produce a digitized image or high speed video rendering a thermal map of the scene in false colour. Since temperature is an important environmental parameter influencing animal physiology and metabolic heat production an energetically expensive process, measuring temperature and energy exchange in animals is critical to understanding physiology, especially under field conditions. As a non-contact approach, infrared thermography provides a non-invasive complement to physiological data gathering. One caveat, however, is that only surface temperatures are measured, which guides much research to those thermal events occurring at the skin and insulating regions of the body. As an imaging technique, infrared thermal imaging is also subject to certain uncertainties that require physical modeling, which is typically done via built-in software approaches. Infrared thermal imaging has enabled different insights into the comparative physiology of phenomena ranging from thermogenesis, peripheral blood flow adjustments, evaporative cooling, and to respiratory physiology. In this review, I provide background and guidelines for the use of thermal imaging, primarily aimed at field physiologists and biologists interested in thermal biology. I also discuss some of the better known approaches and discoveries revealed from using thermal imaging with the objective of encouraging more quantitative assessment.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Higher plants have evolved a well-conserved set of photoprotective mechanisms, collectively designated Non-Photochemical Quenching of chlorophyll fluorescence (qN), to deal with the inhibitory absorption of excess light energy by the photosystems. Their main contribution originates from safe thermal deactivation of excited states promoted by a highly-energized thylakoid membrane, detected via lumen acidification. The precise origins of this energy- or LlpH-dependent quenching (qE), arising from either decreased energy transfer efficiency in PSII antennae (~ Young & Frank, 1996; Gilmore & Yamamoto, 1992; Ruban et aI., 1992), from alternative electron transfer pathways in PSII reaction centres (~ Schreiber & Neubauer, 1990; Thompson &Brudvig, 1988; Klimov et aI., 1977), or from both (Wagner et aI., 1996; Walters & Horton, 1993), are a source of considerable controversy. In this study, the origins of qE were investigated in spinach thylakoids using a combination of fluorescence spectroscopic techniques: Pulse Amplitude Modulated (PAM) fluorimetry, pump-probe fluorimetry for the measurement of PSII absorption crosssections, and picosecond fluorescence decay curves fit to a kinetic model for PSII. Quenching by qE (,..,600/0 of maximal fluorescence, Fm) was light-induced in circulating samples and the resulting pH gradient maintained during a dark delay by the lumenacidifying capabilities of thylakoid membrane H+ ATPases. Results for qE were compared to those for the addition of a known antenna quencher, 5-hydroxy-1,4naphthoquinone (5-0H-NQ), titrated to achieve the same degree of Fm quenching as for qE. Quenching of the minimal fluorescence yield, F0' was clear (8 to 130/0) during formation of qE, indicative of classical antenna quenching (Butler, 1984), although the degree was significantly less than that achieved by addition of 5-0H-NQ. Although qE induction resulted in an overall increase in absorption cross-section, unlike the decrease expected for antenna quenchers like the quinone, a larger increase in crosssection was observed when qE induction was attempted in thylakoids with collapsed pH gradients (uncoupled by nigericin), in the absence of xanthophyll cycle operation (inhibited by DTT), or in the absence of quenching (LlpH not maintained in the dark due to omission of ATP). Fluorescence decay curves exhibited a similar disparity between qE-quenched and 5-0H-NQ-quenched thylakoids, although both sets showed accelerated kinetics in the fastest decay components at both F0 and Fm. In addition, the kinetics of dark-adapted thylakoids were nearly identical to those in qEquenched samples at F0' both accelerated in comparison with thylakoids in which the redox poise of the Oxygen-Evolving Complex was randomized by exposure to low levels of background light (which allowed appropriate comparison with F0 yields from quenched samples). When modelled with the Reversible Radical Pair model for PSII (Schatz et aI., 1988), quinone quenching could be sufficiently described by increasing only the rate constant for decay in the antenna (as in Vasil'ev et aI., 1998), whereas modelling of data from qE-quenched thylakoids required changes in both the antenna rate constant and in rate constants for the reaction centre. The clear differences between qE and 5-0H-NQ quenching demonstrated that qE could not have its origins in the antenna alone, but is rather accompanied by reaction centre quenching. Defined mechanisms of reaction centre quenching are discussed, also in relation to the observed post-quenching depression in Fm associated with photoinhibition.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Phospholipids in water form lamellar phases made up of alternating layers of water and bimolecular lipid leaflets. Three complementary methods, osmotic, mechanical, and vapour pressures, were used to measure the work of removing water from lamellar phases composed of frozen dipalmitoylphosphatidylcholine ( DPPC ), melted DPPC, egg phosphatidylethanolamine or equimolar mixtures of DPPC and cholesterol ( DPPC/CHOL ), Concurrently the structural changes that resulted from this water removal were measured using X-ray diffraction. The work was divided into that which forces the bilayers together ( F ) and that which compresses the molecules together within the bilayers ( F )# A large repulsive force exists between bilayers composed of each of the lipids studied and this force increases exponentially as bilayer separation is decreased. F is affected by the nature of the head groups, conformation of the acyl chains and heterogeneity of these chains. In general all of the melted phosphatidylcholines ( melted DPPC, egg lecithin and DPPC/CHOL ) have large equilibrium separations in excess water resulting from large repulsive hydration forces between these bilayers. By comparison, egg PE has an increased attractive force, and frozen DPPC has a decreased hydration force; each results in smaller separations in water for these two lipids. The chemical potentials of the water between the bilayers for all these lipids lie on a continuum, indicating that interbilayer water cannot be characterized by two discrete states, usually referred to as "bound" or "non**bound". For all lipids studied a maximum of 25 % of the total work done on the system goes into deforming the bilayers. The method used here viii to separate repulsion from deformation, developed for us by v. A. Parsegian, provides a unique method for the measurement of lateral pressure of a bilayer and its modulus of deformability ( Y ). Lateral pressure is affected by the nature of the head group, conformation and heterogeneity of the acyl chains. For small changes in molecular surface area ( A ) near equilibrium, both melted and frozen DPPC have similar values for the deformability modulus. Thus in this regime it requires about the same force to change the angle of tilt of frozen chains as it does to compress the fluid bilayer. The introduction of cholesterol into bilayers of DPPC reduces dramatically the lateral pressure of the bilayers over a large range of molecular surface areas ( A ). The variation in the magnitude of bilayer repulsion with different phospholipids provides a basis for the mechanism of lipid segregation in mixed lipid systems and suggests that interacting heterogeneous membranes may influence or modulate the composition of the opposing membrane. The measurements of deformabilities of bilayers provides a direct comparison of them with the properties of monolayers.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

. The influence of vine water status was studied in commercial vineyard blocks of Vilis vinifera L. cv. Cabernet Franc in Niagara Peninsula, Ontario from 2005 to 2007. Vine performance, fruit composition and vine size of non-irrigated grapevines were compared within ten vineyard blocks containing different soil and vine water status. Results showed that within each vineyard block water status zones could be identified on GIS-generated maps using leaf water potential and soil moisture measurements. Some yield and fruit composition variables correlated with the intensity of vine water status. Chemical and descriptive sensory analysis was performed on nine (2005) and eight (2006) pairs of experimental wines to illustrate differences between wines made from high and low water status winegrapes at each vineyard block. Twelve trained judges evaluated six aroma and flavor (red fruit, black cherry, black current, black pepper, bell pepper, and green bean), thr~e mouthfeel (astringency, bitterness and acidity) sensory attributes as well as color intensity. Each pair of high and low water status wine was compared using t-test. In 2005, low water status (L WS) wines from Buis, Harbour Estate, Henry of Pelham (HOP), and Vieni had higher color intensity; those form Chateau des Charmes (CDC) had high black cherry flavor; those at RiefEstates were high in red fruit flavor and at those from George site was high in red fruit aroma. In 2006, low water status (L WS) wines from George, Cave Spring and Morrison sites were high in color intensity. L WS wines from CDC, George and Morrison were more intense in black cherry aroma; LWS wines from Hernder site were high in red fruit aroma and flavor. No significant differences were found from one year to the next between the wines produced from the same vineyard, indicating that the attributes of these wines were maintained almost constant despite markedly different conditions in 2005 and 2006 vintages. Partial ii Least Square (PLS) analysis showed that leaf \}' was associated with red fruit aroma and flavor, berry and wine color intensity, total phenols, Brix and anthocyanins while soil moisture was explained with acidity, green bean aroma and flavor as well as bell pepper aroma and flavor. In another study chemical and descriptive sensory analysis was conducted on nine (2005) and eight (2006) medium water status (MWS) experimental wines to illustrate differences that might support the sub-appellation system in Niagara. The judges evaluated the same aroma, flavor, and mouthfeel sensory attributes as well as color intensity. Data were analyzed using analysis of variance (ANOVA), principal component analysis (PCA) and discriminate analysis (DA). ANOV A of sensory data showed regional differences for all sensory attributes. In 2005, wines from CDC, HOP, and Hemder sites showed highest. r ed fruit aroma and flavor. Lakeshore and Niagara River sites (Harbour, Reif, George, and Buis) wines showed higher bell pepper and green bean aroma and flavor due to proximity to the large bodies of water and less heat unit accumulation. In 2006, all sensory attributes except black pepper aroma were different. PCA revealed that wines from HOP and CDC sites were higher in red fruit, black currant and black cherry aroma and flavor as well as black pepper flavor, while wines from Hemder, Morrison and George sites were high in green bean aroma and flavor. ANOV A of chemical data in 2005 indicated that hue, color intensity, and titratable acidity (TA) were different across the sites, while in 2006, hue, color intensity and ethanol were different across the sites. These data indicate that there is the likelihood of substantial chemical and sensory differences between clusters of sub-appellations within the Niagara Peninsula iii

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Frank C. (Case) McCordick (1873-1946) was the son of William Henry (1849-1930) and Emily D. Howell (1851-1927) McCordick. William H. McCordick was in the coal business. The McCordick family included Frank Case, Mabel Gertrude, Ethel Howell and Arthur Stanley. Frank C. McCordick was educated in St. Catharines, and worked with his father in the coal business and eventually opened up a leather tanning operation. McCordick was active in the Lincoln Regiment and in 1906 was promoted to captain and in command of Company A, 19th Regiment. He was promoted to major and at the outbreak of war he was sent overseas as a commander of the 35th Battalion of the Canadian Expeditionary Forces (CEF). Upon arrival in France he was made officer commanding the 15th Battalion, King’s Own Yorkshire Light Infantry (KOYLI). After the war and his return to Canada he continued to play an active role in the local military units in the area as well as in Hamilton. After his retirement from the military in 1927 McCordick served as alderman and then mayor of St. Catharines from 1930 to 1931. He was a member of a large number of civic clubs, including St. Catharines Chamber of Commerce, Y.M.C.A., Lion’s Club, St. Catharines Golf Club, Detroit Boat Club, the St Catharines Club, as well as a member of several Masonic lodges. He continued to operate McCordick Tannery and other local investments. In 1903 Frank C. McCordick married May Beatrice Simson, daughter of Thomas E. Simson of Thorold. They had three children, E. (Edward) Frank McCordick, Bruce McCordick and (Margaret) Doris McCordick (m. Hubert Grigaut, d. 1977). The McCordick family resided at 82 Yates Street, near Adams Street. May Simson McCordick (b. 1873) was the daughter of Thomas Edward (1836-1908) and Julia Headlam (1844-1887) Simson of Thorold. Her siblings included: Edward, Frances, John, Augusta, Georgia and Gertrude. E. (Edward) Frank McCordick (1904-1980) was born in St. Catharines, Ont., attended Lake Lodge School in Grimsby, Ridley College in St. Catharines, Beechmont Preparatory School in England, Upper Canada College in Toronto and graduated from Royal Military College in Kingston, Ont. in 1925. Upon graduation he was made a lieutenant in the 10th (St. Catharines) Field Battery. In 1929 he married Helen Stanley Smith, daughter of Stanley George and Mary Walker Smith of St. Catharines. Col. McCordick, now promoted to Major, played an active role in the 10th (St. Catharines) Field Battery, being officer commanding the battery. In late 1939 McCordick headed to England for artillery tactical training and on December 6, 1939 the battery began the long trek overseas. McCordick saw action in Italy and in Holland. Upon his return to Canada at the end of the war he was the Liberal candidate in the federal election for Lincoln County. He remained active in the local military serving as honorary lieutenant-colonel of the 56th Field Regiment (ARCA) and in 1976 as the honorary colonel of the regiment. Col. McCordick held the Efficiency Decoration, the Order of the British Empire, granted in 1945 and was made an officer in the Order of St. John in 1978. He continued to serve his community in various capacities, including the Unemployment Insurance Canada Board, Royal Trust Company and the St. John Ambulance Society. He remained an active member of the alumni of Royal Military College, editing and compiling a newsletter and organizing reunion weekends. He kept in close contact with many of his classmates. Helen Stanley Smith McCordick lived in St. Catharines, Ont., attended Robertson School, and graduated from the University of Toronto in 1926 with a Bachelor of Arts degree in Modern Languages. During the war years (1939-1945) Helen was active in the Transport division of the local branch of the Canadian Red Cross and the Women’s Auxiliary of the 10th Field Battery. In 1932 E. Frank and Helen McCordick welcomed their only child, (Catharine) Anne McCordick. Helen continued to play an active role in her community until her passing in 1997. Stanley George Smith (1865-1960) was born in St. Catharines, Ont., the only child of William Smith (d. June 16, 1876) a native of Edinburgh, Scotland and his wife Hannah Louisa Maria Bulkeley a native of Fairfield, Connecticut. Stanley George Smith married Mary Walker of Guelph, Ont.(d. 1956) Mary was the daughter of Hugh and Elizabeth (d. 1924) Walker. Her siblings included Margaret, Agnes, Jessie, Isabella, Lorne, Ada, Alice, Eva, Alexander and George. Hugh Walker was a prominent fruit and vegetable merchant in Guelph. On 1904 their only child, Helen Stanley Smith was born. He was a post office clerk, and the treasurer for the James D. Tait Co. Ltd., a clothing and dry goods retailer in St. Catharines. The family lived at 39 Church Street in St. Catharines, Ont.