12 resultados para contact forces

em Brock University, Canada


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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.

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Electrostatic forces between membranes containing charged lipids were assumed to play an important role in influencing interactions between membranes long before quantitative measurements of such forces were available. ~ur measurements were designed to measure electrostatic forces between layers of lecithin charged with lipi~s carrying ionizable head groups. These experiments have shown that the interactions between charged lipid bila.yere are dominated by electrostatic forces only at separations greater than 30 A. At smaller separations the repulsion between charged bilayers is dominated by strong hydration forces. The net repulsive force between egg lecithin bilayers containing various amounts of cherged lipids (phosphatidylglycerol (PG) 5,10 ano 50 mole%, phosphatidyli. nosi tol (PI) 10 mole% and sodium oleate (Na-Ol) 3,5 and 10 mole%, where mole% gives the ratio of the number of moles' of .charged lipid to the total number of moles of all lipids present in the sample) was stuoied with the help ('If the osmotic streas technique described by LeNeveu et aI, (1977). Also, the forces between pure PG were j_nvestigated in the same manner. The results have been plotted showing variation of force as a function of bilay- _ er separation dw• All curVes 90 obtained called force curves, were found to be similar in sha.pe, showing two distinct regions, one when dw<.30 A is a region cf very rapid iiivariation of force with separation ( it is the region dominated by hydre,tion force) and second when dw> 40 A is a region of very slow variation of force with separB.tion ( it is the region dominated by the electrostatic force). Between these two regions there exists a transition area in which, in most systems studied, a phase separation of lipids into fractions containing different amounts of charged groups, was observed. A qualitative analysis showed that our results were v/ell described by the simple electrostatic double -le.yer theory. For quantitative agreement between measured and calculated force curves however, the charge density for the calculations had to be taken as half of that given by the number density of charged lipids present in the lecithin bilayers. It is not clear at the moment what causes such low apparent degree of ionization among the charged head groups, and further study is needed in this area.

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Various s e t s of single c rys t a l s and poly c rys t a l s of Cux TiSe2 were grown. X- r ay diffraction and ene rgy dispersive spe c t ros copy r e sul t s verified tha t the c rys t a l s were the cor r e c t compos i t ion and c rys t a l s t ruc tur e . Re s i s t ivi ty me a sur ement s and magne t i c sus c ept ibi l i ty me a sur ement s de t e rmined the supe r conduc t ing t r ans i t ion t empe r a tur e s for the c rys t a l s . The c rys t a l s in each growth had various supe r conduc t ing t r ans i t ion t empe r a tur e s . Also, the me a sur ement s indi c a t ed tha t the c rys t a l s were inhomogeneous. Point cont a c t spe c t ros copy expe r iment s were employed on various single c rys t a l s . Inspe c t ion of the da t a indi c a t ed tha t the ma t e r i a l ha s a single ene rgy gap . A progr am was bui l t ut i l i z ing the Levenbe rg-Ma rqua rdt me thod and theory on point cont a c t spe c t ros copy to de t e rmine the supe r conduc t ing ene rgy gap. Plot s of the supe r conduc t ing ene rgy gap a t various t empe r a tur e s were in di s agr e ement wi th wha t was expe c t ed for a convent iona l supe r conduc tor .

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Full Title: Report of the Committee appointed to inquire into the Present condition and distribution of the flags, standards and colors, which have been taken by the forces of the United States from their enemies, and whether it would be expedient to make any provision in relation to them Adam Seybet, Chairman. Exhibit folded at end of text. February 4, 1814. Read, and committed to a committee of the whole House on Monday next. Printed by A and G Way

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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.

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Research on sexuality in Ghana has been scanty due to the nature of the Ghanaian society where sensitive issues like sexuality are not openly discussed and researched. This qualitative study examined how social contact with Canadian society has impacted the views of Ghanaian students living in Canada about sexuality. The data for this research study were gathered through in-depth interviews with 15 Ghanaian students between ages18 to 30 who had been living in Canada for more than one year. This study’s findings revealed that religion plays a central role in shaping views about sexuality among young Ghanaians living in Canada. The findings also highlighted the impact of cultural contact in shaping several aspects of sexuality including contraception and same-sex relations. The theoretical implications of this study’s results are discussed in terms of how they can help to clarify culturally informed models focusing on the role played by society, religion, family and peers in the development of adolescent perspectives about sexuality. The practical and educational implications of this study’s results are also discussed.

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A prisoner interrogation report dated 27 May 1918. The report reads: "I. PRISONER X. 1st. Battalion, 272 Res. Rogt., 82d Res. 1. CIRCUMSTANCES OF CAPTURE; Captured, while attempting to raid our trenches, at point 1719 at about 7A.M. 2. INFORMATION OBTAINED FROM PRISONER (a) Between point 1814 and point 175242 the German trenches appear to be held by three companies, each numbering 3 platoons, each platoon numbering about 40 men. Each company has 4 light machine guns in the first lines, these machine guns distributed along the first trench (one of them in particular is located at bond in hostile trench at point 17215 and another at about 17245. Each company, furthermore, has one platoon (weak in numbers) in support in the ravine north of Cantigny. These platoons are in dugouts dug into the side of the hill approximately between points 28215 and 2223. Each of these support platoons has two light machine guns at its disposal. Company commanders dugout is at some point along the line of dugouts occupied by the support platoons. Another company commander's dugout (Co.3) is at point 1815 about 15 meters behind the German trench which runs along the edge of the town of Cantigny. There is a communication trench between the cemetery at 2018 and the front line at 18179. It is believed that there is a machine gun at point 17245 kept in a dugout dug under the road. The reserve battalion is believed to be at a fairly great distance from the front (near Bouillancourt). The prisoner, on the other hand, states that it may have been moved up."

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This study was conducted to measure the degree of adherence by public health care providers to a policy that requires them to implement minimal contact intervention for tobacco cessation with their clients. This study also described what components of the intervention may have contributed to the adherence of the policy and how health care providers felt about adhering to the policy. The intervention consisted of a policy for implementation of minimal contact intervention, changes to documentation, a health care provider mentor trained, a training session for health care providers, and ongoing paper and people supports for implementation. Data for this study were collected through a health care provider questionnaire, focus group interviews, and a compliance protocol including a chart audit. The findings of this study showed a high degree of adherence to the policy, that health care providers thought minimal contact intervention was important to conduct with their clients, and that health care providers felt supported to implement the intervention. No statistically significant difference was found between new and experienced health care providers on 17 of the 18 questions on the health care provider questionnaire. However there was a statistically significant difference between new and experienced health care providers with respect to their perception that “clients often feel like they have to accept tobacco cessation information from me.” Changes could be made to the minimal contact intervention and to documentation of the intervention. Implications for future research include implementation within other programs within Hamilton Public Health Services and implementation of this model within other public health units and other types of health care providers within Ontario.

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There is a note in the front cover written to Mary from B. Johnston on April 22, 1942. He refers to page 73 of the book in which William Woodruff is listed as a Lieutenant and Richard Woodruff is listed as an Ensign in the Niagara District. A full text version is available at the following link: http://www.archive.org/details/officersbritish00instgoog

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Abstract It is recommended that all new mothers experience skin-to-skin contact (SSC) with their newborns immediately after birth. However, SSC is not commonly practiced after cesarean deliveries. To understand facilitators and barriers regarding SSC in the operating room (OR), a descriptive online and paper survey was conducted with 68 Registered Nurses from four hospitals in Ontario. The theory of planned behavior framed the study. Nurses had positive attitudes, and believed most health care team members supported SSC in the OR, but were uncertain about their control over the behavior. Nurses who had practiced the behavior in the past had more positive attitudinal and normative beliefs, and perceived some barriers as less difficult. Attitude and past behavior were the only significant multivariate predictors of intention to practice SSC in the future. Results suggest that shifting attitude and supporting more experience with the practice may increase nurses’ implementation of SSC in the OR.