Development and testing of a two-phase flow pressure drop calculation tool

Öljynjalostusteollisuudessa kaasun ja nesteen kaksifaasivirtausta esiintyy todennäköisimmin tarkasteltaessa lauhduttimia, tislauskolonnien kiehuttimia, prosessiuuneja sekä erityisesti näiden yhteyteen rakennettuja putkilinjoja. Koska kaksifaasivirtaus on fysikaalisesti yksifaasivirtausta huomattavasti monimutkaisempi ilmiö, ei jälkimmäisen kohdalla käytettyjä putkiston ja laitteiden mitoitusmetodeja voida suoraan soveltaa kaksifaasivirtaukselle. Kaksifaasivirtauksen painehäviön riittävän tarkka laskenta on kuitenkin edellytyksenä sitä käsittelevien prosessiyksiköiden turvalliselle ja tehokkaalle toiminnalle. Painehäviön lisäksi prosessisuunnittelijaa kiinnostaa kaksifaasivirtauksen virtaustyyppi, sillä sopivissa olosuhteissa kaksifaasivirtaukseen voi muodostua virtaustyyppejä, jotka nopeuttavat laitteen tai putkilinjan kulumista sekä voivat pahimmillaan johtaa laite- ja putkistovaurioihin. Kirjallisen osan ensimmäisessä luvussa tarkastellaan kaksifaasivirtauksen virtaustyyppejä sekä kulloinkin vallitsevan virtaustyypin selvittämiseen käytettäviä työkaluja, virtausaluekarttoja. Seuraavissa luvuissa käydään läpi eroosion ja korroosion esiintymistä kaksifaasivirtauksen yhteydessä sekä näiden ilmiöiden vaikutusta putkilinjojen ja laitteiden mitoitukseen, sekä tarkastellaan kaksifaasivirtauksen tukehtumista ilmiönä sekä erilaisia menetelmiä tukehtumisnopeuden laskentaan. Viimeisessä osiossa käydään läpi Lockahartin ja Martinellin sekä Beggsin ja Brillin painehäviölaskentametodit. Lopussa luodaan vielä katsaus painehäviölaskentametodien tarkkuutta vertaileviin artikkeleihin, joiden perusteella tarkimpia olisivat Friedelin sekä Beggsin ja Brillin painehäviölaskentametodit. Soveltavan osan alkupuolella tarkastellaan laskentatyökalun kehitystä sekä siinä tehtyjä ratkaisuja. Laskentatyökaluun sisällytettiin Beggsin ja Brillin sekä H.T.F.S.:n painehäviölaskentamenetelmät vapaalle putkivirtaukselle, minkä lisäksi paikallisvastusten laskenta toteutettiin pääasiassa H.T.F.S.:n menetelmien pohjalta. Toisessa vaiheessa tarkastellaan työkalun toimintaa vertailemalla sillä laskettuja arvoja kahdesta erillisestä prosessiteollisuuden yksiköstä saatuihin virtaustietoihin. Kummankin yksikön kohdalla havaittiin lasketun painehäviön olleen 30 – 50 % erisuuruinen mittaustuloksiin verrattuna. Beggsin ja Brillin metodi arvioi painehäviön 10 – 20 % H.T.F.S.:n vastaavaa suuremmaksi, suuremmasta kitkahäviöstä johtuen. Näiden tulosten pohjalta voidaan todeta, että kaksifaasivirtauksen painehäviön ennustaminen on huomattavan vaikeaa. Toisaalta mallien absoluuttisesta tarkkuudesta ei näin vähäisellä laskentatapausten määrällä voida tehdä kunnollisia johtopäätöksiä.In oil refining industry gas-liquid two-phase flow occurs most likely in condensers, distillation column reboilers, process furnaces and especially in the connecting pipelines. As two-phase flow is physically much more complicated phenomenon than single-phase flow, the same methods used to design single-phase flow piping and equipment cannot be directly applied to two-phase flow. Sufficiently accurate estimation of two-phase flow pressure drop is, however, a prerequisite for safe and effective operation of the equipment handling two-phase flow. In addition to the pressure drop, process engineer is interested in the flow pattern of two-phase flow, as in suitable conditions two-phase flow can comprise of flow patterns, which can speed up erosion of equipment or pipeline or can even result in damage to equipment or piping. First chapter of the literature part examines the flow patterns which can occur in two-phase flow, as well as the tools used to determine the prevailing flow pattern, known as flow regime maps. The following chapters investigate erosion and corrosion occurring in equipment and pipelines handling two-phase flow. Following that, the choking phenomenon of two-phase flow and the methods to calculate the choking flow rate are introduced. Last section of the literature part examines Lockhart and Martinelli and Beggs and Brill pressure drop calculation methods. In the end of the literature part, articles concerning the accuracy of different pressure drop methods are reviewed. According to those articles methods of Friedel and Beggs and Brill seem to be the most accurate. In the beginning of the applied part, development of the pressure drop calculation tool is examined. Pressure drop methods incorporated in the calculation tool were Beggs and Brill and H.T.F.S. In addition, pressure drops for bends and fittings were set to be calculated with H.T.F.S. correlations. Following chapter of the applied part concerns operation of the pressure drop calculation tool by comparing the calculated pressure drop values to information derived from two separate process units. Calculated pressure drops were found to differ 30 – 50 % compared to information derived from process units. Beggs and Brill method estimated the pressure drop to be 10 – 20 % higher than the equivalent H.T.F.S. value, due to higher frictional pressure drop. Due to these results, it can be concluded that it is difficult to reliably estimate two-phase flow pressure drops. On the other hand, proper conclusions about the absolute accuracy of the pressure drop models cannot be done, due to low amount of calculation cases

Metaforia, piirroksia ja akronyymeja – työkaluja kieltenopettajan käyttöteorian rakentamiseen ja vahvistamiseen ohjatussa harjottelussa

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A 96-well format for a high-throughput baculovirus generation, fast titering and recombinant protein production in insect and mammalian cells

<p>Abstract</p> <p>Background</p> <p>Baculovirus expression vector system (BEVS) has become a standard in recombinant protein production and virus-like particle preparation for numerous applications.</p> <p>Findings</p> <p>We describe here protocols which adapt baculovirus generation into 96-well format.</p> <p>Conclusion</p> <p>The established methodology allows simple baculovirus generation, fast virus titering within 18 h and efficient recombinant protein production in a high-throughput format. Furthermore, the produced baculovirus vectors are compatible with gene expression in vertebrate cells <it>in vitro </it>and <it>in vivo</it>.</p

Structure and characterization of a novel chicken biotin-binding protein A (BBP-A)

BACKGROUND: The chicken genome contains a BBP-A gene showing similar characteristics to avidin family genes. In a previous study we reported that the BBP-A gene may encode a biotin-binding protein due to the high sequence similarity with chicken avidin, especially at regions encoding residues known to be located at the ligand-binding site of avidin. RESULTS: Here, we expand the repertoire of known macromolecular biotin binders by reporting a novel biotin-binding protein A (BBP-A) from chicken. The BBP-A recombinant protein was expressed using two different expression systems and purified with affinity chromatography, biochemically characterized and two X-ray structures were solved – in complex with D-biotin (BTN) and in complex with D-biotin D-sulfoxide (BSO). The BBP-A protein binds free biotin with high, "streptavidin-like" affinity (K(d )~ 10(-13 )M), which is about 50 times lower than that of chicken avidin. Surprisingly, the affinity of BBP-A for BSO is even higher than the affinity for BTN. Furthermore, the solved structures of the BBP-A – BTN and BBP-A – BSO complexes, which share the fold with the members of the avidin and lipocalin protein families, are extremely similar to each other. CONCLUSION: BBP-A is an avidin-like protein having a β-barrel fold and high affinity towards BTN. However, BBP-A differs from the other known members of the avidin protein family in thermal stability and immunological properties. BBP-A also has a unique ligand-binding property, the ability to bind BTN and BSO at comparable affinities. BBP-A may have use as a novel material in, e.g. modern bio(nano)technological applications

Structure and characterization of a novel chicken biotin-binding protein A (BBP-A)

Background. The chicken genome contains a BBP-A gene showing similar characteristics to avidin family genes. In a previous study we reported that the BBP-A gene may encode a biotin-binding protein due to the high sequence similarity with chicken avidin, especially at regions encoding residues known to be located at the ligand-binding site of avidin. Results. Here, we expand the repertoire of known macromolecular biotin binders by reporting a novel biotin-binding protein A (BBP-A) from chicken. The BBP-A recombinant protein was expressed using two different expression systems and purified with affinity chromatography, biochemically characterized and two X-ray structures were solved – in complex with D-biotin (BTN) and in complex with D-biotin D-sulfoxide (BSO). The BBP-A protein binds free biotin with high, "streptavidin-like" affinity (Kd ~ 10-¹³ M), which is about 50 times lower than that of chicken avidin. Surprisingly, the affinity of BBP-A for BSO is even higher than the affinity for BTN. Furthermore, the solved structures of the BBP-A – BTN and BBP-A – BSO complexes, which share the fold with the members of the avidin and lipocalin protein families, are extremely similar to each other. Conclusion. BBP-A is an avidin-like protein having a β-barrel fold and high affinity towards BTN. However, BBP-A differs from the other known members of the avidin protein family in thermal stability and immunological properties. BBP-A also has a unique ligand-binding property, the ability to bind BTN and BSO at comparable affinities. BBP-A may have use as a novel material in, e.g. modern bio(nano)technological applications.peerReviewe

Removal of cell surface heparan sulfate increases TACE activity and cleavage of ErbB4 receptor

<p>Abstract</p> <p>Background</p> <p>Nuclear localization of proteolytically formed intracellular fragment of ErbB4 receptor tyrosine kinase has been shown to promote cell survival, and nuclear localization of ErbB4 receptor has been described in human breast cancer. Tumor necrosis factor alpha converting enzyme (TACE) initiates the proteolytic cascade leading to ErbB4 intracellular domain formation. Interactions between matrix metalloproteases and heparan sulfate have been described, but the effect of cell surface heparan sulfate on TACE activity has not been previously described.</p> <p>Results</p> <p>As indicated by immunodetection of increased ErbB4 intracellular domain formation and direct enzyme activity analysis, TACE activity was substantially amplified by enzymatic removal of cell surface heparan sulfate but not chondroitin sulfate.</p> <p>Conclusion</p> <p>In this communication, we suggest a novel role for cell surface heparan sulfate. Removal of cell surface heparan sulfate led to increased formation of ErbB4 intracellular domain. As ErbB4 intracellular domain has previously been shown to promote cell survival this finding may indicate a novel mechanism how HS degradation active in tumor tissue may favor cell survival.</p

Human breast cancer cells educate macrophages toward the M2 activation status

Abstract Introduction The immune system plays a major role in cancer progression. In solid tumors, 5-40 % of the tumor mass consists of tumor-associated macrophages (TAMs) and there is usually a correlation between the number of TAMs and poor prognosis, depending on the tumor type. TAMs usually resemble M2 macrophages. Unlike M1-macrophages which have pro-inflammatory and anti-cancer functions, M2-macrophages are immunosuppressive, contribute to the matrix-remodeling, and hence favor tumor growth. The role of TAMs is not fully understood in breast cancer progression. Methods Macrophage infiltration (CD68) and activation status (HLA-DRIIα, CD163) were evaluated in a large cohort of human primary breast tumors (562 tissue microarray samples), by immunohistochemistry and scored by automated image analysis algorithms. Survival between groups was compared using the Kaplan-Meier life-table method and a Cox multivariate proportional hazards model. Macrophage education by breast cancer cells was assessed by ex vivo differentiation of peripheral blood mononuclear cells (PBMCs) in the presence or absence of breast cancer cell conditioned media (MDA-MB231, MCF-7 or T47D cell lines) and M1 or M2 inducing cytokines (respectively IFN-γ, IL-4 and IL-10). Obtained macrophages were analyzed by flow cytometry (CD14, CD16, CD64, CD86, CD200R and CD163), ELISA (IL-6, IL-8, IL-10, monocyte colony stimulating factor M-CSF) and zymography (matrix metalloproteinase 9, MMP-9). Results Clinically, we found that high numbers of CD163+ M2-macrophages were strongly associated with fast proliferation, poor differentiation, estrogen receptor negativity and histological ductal type (p<0.001) in the studied cohort of human primary breast tumors. We demonstrated ex vivo that breast cancer cell-secreted factors modulate macrophage differentiation toward the M2 phenotype. Furthermore, the more aggressive mesenchymal-like cell line MDA-MB231, which secretes high levels of M-CSF, skews macrophages toward the more immunosuppressive M2c subtype. Conclusions This study demonstrates that human breast cancer cells influence macrophage differentiation and that TAM differentiation status correlates with recurrence free survival, thus further emphasizing that TAMs can similarly affect therapy efficacy and patient outcome

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Immunohistochemical analysis conditions. (PDF 273 kb

Effect of remdesivir post hospitalization for COVID-19 infection from the randomized SOLIDARITY Finland trial

We report the first long-term follow-up of a randomized trial (NCT04978259) addressing the effects of remdesivir on recovery (primary outcome) and other patient-important outcomes one year after hospitalization resulting from COVID-19. Of the 208 patients recruited from 11 Finnish hospitals, 198 survived, of whom 181 (92%) completed follow-up. At one year, self-reported recovery occurred in 85% in remdesivir and 86% in standard of care (SoC) (RR 0.94, 95% CI 0.47-1.90). We infer no convincing difference between remdesivir and SoC in quality of life or symptom outcomes (p > 0.05). Of the 21 potential long-COVID symptoms, patients reported moderate/major bother from fatigue (26%), joint pain (22%), and problems with memory (19%) and attention/concentration (18%). In conclusion, after a one-year follow-up of hospitalized patients, one in six reported they had not recovered well from COVID-19. Our results provide no convincing evidence of remdesivir benefit, but wide confidence intervals included possible benefit and harm.Peer reviewe