Extending vaterite microviscometry to ex vivo blood vessels by serial calibration

The endothelial glycocalyx layer is a ~2 µm thick glycosaminoglycan rich pericellular matrix expressed on the luminal surface of vascular endothelial cells, which has implications in vessel mechanics and mechanotransduction. Despite its role in vascular physiology, no direct measurement has of yet been made of vessel glycocalyx material properties. Vaterite microviscometry is a laser tweezers based microrheological method, which has been previously utilized to measure the viscosity of linear and complex fluids under flow. This form of microrheology has until now relied on complete recollection of the forward scattered light. Here we present a novel method to extend vaterite microviscometry to relatively thick samples. We validate our method and its assumptions and measure the apparent viscosity as a function of distance from the vascular endothelium. We observe a differential response in conditions designed to preserve the EGL in comparison to those designed to collapse it

Hemorheology and Microvascular Disorders

The present review presents basic concepts of blood rheology related to vascular diseases. Blood flow in large arteries is dominated by inertial forces exhibited at high flow velocities, while viscous forces (i.e., blood rheology) play an almost negligible role. When high flow velocity is compromised by sudden deceleration as at a bifurcation, endothelial cell dysfunction can occur along the outer wall of the bifurcation, initiating inflammatory gene expression and, through mechanotransduction, the cascade of events associated with atherosclerosis. In sharp contrast, the flow of blood in microvessels is dominated by viscous shear forces since the inertial forces are negligible due to low flow velocities. Shear stress is a critical parameter in microvascular flow, and a force-balance approach is proposed for determining microvascular shear stress, accounting for the low Reynolds numbers and the dominance of viscous forces over inertial forces. Accordingly, when the attractive forces between erythrocytes (represented by the yield stress of blood) are greater than the shear force produced by microvascular flow, tissue perfusion itself cannot be sustained, leading to capillary loss. The yield stress parameter is presented as a diagnostic candidate for future clinical research, specifically, as a fluid dynamic biomarker for microvascular disorders. The relation between the yield stress and diastolic blood viscosity (DBV) is described using the Casson model for viscosity, from which one may be able determine thresholds of DBV where the risk of microvascular disorders is high

Letter from Julia M[errill] Moores to [John Muir], 1881 Jan12.

[4]it to say – that they succeeded admirably though sometimes a little impudent. On New Year’s eve – in my brother’s parlors – a company of some thirty or forty men assembled, The Authors read aloud chapter about to the characters – the story they had written. it was received with shouts of laughter & applause. There was as you may imagine a great taking down of Merrile Moores – and some others. But all disrespect and impudence was forgiven & counted for naught for we were well unpaid by the sprightliness of the story. Here I have written you no news – The family is well – Merrill hard at work – Charles & Charley in College doing well – The girls doing duty at home – or in school – as either teachers or scholars – and the mothers & fathers happy in well behaved children. Give much love to your dear wife - & believe me your true friend Julia M. Moores[1]Indianapolis Jan. 12th 1881 232 North Alabama St.My dear friend,Your letter of June I answer in January! I have often had you in my thoughts – and you may be sure that though I have been glad for you in your own home with its ‘snowy linen’ and its dear mistress. I have not felt any anxiety about you. I have thought of you as comfortable & so happy that you did not need my intermeddling. But we are still friends – and I think that as Dr. Johnsen says – ‘Any friendship needs repairs!’ And what repairs are better that what can be done by letter-writing?https://scholarlycommons.pacific.edu/jmcl/36360/thumbnail.jp

Letter from Julia M[errill] Moores to John Muir, 1905 Jun 19.

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Letter from Katharine M[errill] to John Muir, 1895 Apr 23.

[in margin: 808IndianapolisLetters][Apr 23 \u2795]2580 College Ave.Berkeley.Dear Mr. Muir,There is a young woman here, Mina Knapp, on the Call I believe, who wants so much to meet you and talk about birds & kindred things that I have asked her to go up with me some Sunday. Do you care, and may we come a week from Sunday, the 5th? Miss Knapp is01975https://scholarlycommons.pacific.edu/jmcl/26168/thumbnail.jp

Letter from Mary M[errill] Graydon to John Muir, 1901 Apr 26.

1425 Central Ave.,Indianapolis,April 26th, 1901.My dear Mr. Muir:I took your last letter over to Mrs. Victor Hendricks, for them to enjoy too. The last week of Miss Eliza\u27s life she was delirious and although they had a nurse Mrs. Hendricks was worn out - has been ill since. Mr. H. has taken her away. Before leaving she sent me a note, from which I quote, When you write to dear Mr. Muir please remember Mr. Hendricks and me to him most affectionately. His visit to our home was delightful to us. You say truly the Hendricks family show the best in human nature. The pure peculiar sweetness of that home, makes it a light in this community. The Mother\u27s room was the center of that home, and though the children were growing old how gladly they accepted her criticism and advice. I envy no one, but her relations might be envied. Mrs. Victor H.\u27s power lies in her consistency.So many have died this year. Gen. Harrison was a statesman, since Gov. Wallace the greatest honor the state has had. But never again will we see a Mr. Jackson. He was great in his honesty. For years he handled $l,000,000 to$1,500,000 a year without bond. In the civil war Gov. Morton depended on him. Yet his power did not lie in his charity, which ran like a net through all the town, nor in his sympathy, which was as genuine as Christ\u27s. With me it lay in that I could believe what he said. Have charity, but do not call a wrong right. Oh, he was firm. I thank you earnestly for your beautiful words about him. They are precious.You must come East soon, or the rest of us will be dead. Then I long to be refreshed by listening to you. We heard by telegraph Kate had reached Cal. She returns home by the South, stopping in the wilds of Louisiana to see her father. We are all well. Hot weather touched us to-day. Oh, do come in and see us. You are linked at different points along my life, and your talk is always an inspiration.Your friend,Mary M[errill] GraydonDon\u27t I waste a lot of ink?941https://scholarlycommons.pacific.edu/jmcl/40167/thumbnail.jp

Letter from Julia M[errill] Moores to John Muir, 1905 Jun 19.

1960 N.Pennsylvania.,June 19th, 1905.My dear Mr. Muir,I feel like writing to you this summer morning. You will pardon me, I know. I have been looking over old letters of my dear Janet\u27s, and among those treasured by her I find none sweeter or kinder than those written to her by her friend \u27John Muir\u27. You did much to make her happy and she loved you and yours, and I thank you gratefully. I miss her much, yet all of the time I am glad that she is freed from bondage, and in the presence of our Lord. I find many things among those she had kept which show me how loving and lovely her character was. Yet I do not need to be told. In a little memorandum book of hers I find written by her own hand, God has helped me today , I have heard children\u27s voices today , Go to God today . This life is oft perplexing \u27Tis much the wisest plan To brave all trials bravely And smile whene\u27er you can .In one of your letters you say to her, You must be very happy - * and I think you will be happy always . She is happy now.I enclose two little poems which I know you will love to read and will prize them because prized by her.My sons are very dear and are fine men. I thank God for them. My friends are very kind. While I am not at all strong I am glad to live for the sake of my children and grandchildren. The latter are two beautiful ones - I see them every day - they are Emily and Charles, seven and two years old. Merrill sends love. He is a working man, as is his brother. I should be glad to hear from you. My love to your wife and daughters. With love,Julia M. Moores Are we never to see you and yours again?[Envelope inscribed, in Muir\u27s handwriting, Mrs. Moores\u27 last letter about Janet, after the dear girl\u27s death .]03581https://scholarlycommons.pacific.edu/jmcl/28755/thumbnail.jp

Letter from Katharine M[errill] Graydon to John Muir, 1906 Nov 3.

[2]as soon as convenient I mean to make the change. For it I am working, and planning, and praying.It was a disappointment not to see you all as I came th[illegible]. in September, but my visiting was cut short and I did not linger - I could not It is a long while since I have heard of [illegible] from you such stretch of silence I with might not be. I hope you will write soon, and tell of yourself, of Helen\u27s health, of Wanda\u27s marriage, which, by chance, I have heard. Knew I her new have, I should,[3]write her. Oh, tell me everything! I never wander [beyond?] my interest in and affection for the Muirs. That you must know. When does your new book come out? What are you now working on?I bought a lot, while at home, and am pegging away now to accumulate enough to put up a home. Think of it, the Graydons to have their own home before they pass on to their eternal mansion! It seems to good too be true, I pan for that little home by day and by night, and am most eager to accomplish this[in margin: I must tell you that this [illegible] has on it 13 pres[illegible]]https://scholarlycommons.pacific.edu/jmcl/29515/thumbnail.jp

Letter from Katharine M[errill] Graydon to John Muir, 1906 Nov 3.

[2]as soon as convenient I mean to make the change. For it I am working, and planning, and praying.It was a disappointment not to see you all as I came th[illegible]. in September, but my visiting was cut short and I did not linger - I could not It is a long while since I have heard of [illegible] from you such stretch of silence I with might not be. I hope you will write soon, and tell of yourself, of Helen\u27s health, of Wanda\u27s marriage, which, by chance, I have heard. Knew I her new have, I should,[3]write her. Oh, tell me everything! I never wander [beyond?] my interest in and affection for the Muirs. That you must know. When does your new book come out? What are you now working on?I bought a lot, while at home, and am pegging away now to accumulate enough to put up a home. Think of it, the Graydons to have their own home before they pass on to their eternal mansion! It seems to good too be true, I pan for that little home by day and by night, and am most eager to accomplish this[in margin: I must tell you that this [illegible] has on it 13 pres[illegible]]https://scholarlycommons.pacific.edu/jmcl/29515/thumbnail.jp

Letter from Jullia M[errill] Moores to John Muir, 1900 Aug 22.

Aug 22 00[1]1960 N. Pa. St.My dear Mr Muir,Your kind letter of the 24th of July came to me in due time and I thank you for it. It did me good and I have read it again and again. That we may be able to comfort them which are in any trouble, by the comfort wherewith we are comforted of God. Thus you have done my dear friends. Yet I look around in vain for my dear sister. No one knew how much she was to me but myself - and I did not half know![in margin: Charles & Elizabeth are in England for vacation]02721https://scholarlycommons.pacific.edu/jmcl/39890/thumbnail.jp