Accurate and early diagnosis of orthopedic device-related infection by microbial heat production and sonication.

Proper and rapid diagnosis of orthopedic device-related infection is important for successful treatment. Sonication has been shown to improve the diagnostic performance. We hypothesized that the combination of sonication with a novel method called microcalorimetry will further improve and accelerate the diagnosis of implant infection. We prospectively included 39 consecutive patients (mean age 59 years, 62% males) at our institution from whom 29 orthopedic prostheses and 10 osteosynthesis material were explanted. The explanted device was sonicated. The resulting sonication fluid was analyzed using microcalorimetry. Using standardized criteria to define orthopedic device-related infection, 12 cases (31%) were defined as infected. In all, positive periprosthetic tissue cultures were found. The sensitivity and specificity of microcalorimetry of sonication fluid were 100% and 97%, respectively. Mean time to detection, defined as time to reach a rising heat flow signal of 20 µW measured after equilibiration needed to get accurate measurement, was 10.9 h. In summary, microcalorimetry of sonication fluid is a reliable and a fast method in detecting the presence of microorganisms in orthopedic device-related infection. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1700-1703, 2013.

Decreased thermal conductance during the luteal phase of the menstrual cycle in women.

To study the influence of the menstrual cycle on whole body thermal balance and on thermoregulatory mechanisms, metabolic heat production (M) was measured by indirect calorimetry and total heat losses (H) were measured by direct calorimetry in nine women during the follicular (F) and the luteal (L) phases of the menstrual cycle. The subjects were studied while exposed for 90 min to neutral environmental conditions (ambient temperature 28 degrees C, relative humidity 40%) in a direct calorimeter. The values of M and H were not modified by the phase of the menstrual cycle. Furthermore, in both phases the subjects were in thermal equilibrium because M was similar to H (69.7 +/- 1.8 and 72.1 +/- 1.8 W in F and 70.4 +/- 1.9 and 71.4 +/- 1.7 W in L phases, respectively). Tympanic temperature (Tty) was 0.24 +/- 0.07 degrees C higher in the L than in the F phase (P less than 0.05), whereas mean skin temperature (Tsk) was unchanged. Calculated skin thermal conductance (Ksk) was lower in the L (17.9 +/- 0.6 W.m-2.degrees C-1) than in the F phase (20.1 +/- 1.1 W.m-2.degrees C-1; P less than 0.05). Calculated skin blood flow (Fsk) was also lower in the L (0.101 +/- 0.008 l.min-1.m-2) than in the F phase (0.131 +/- 0.015 l.min-1.m-2; P less than 0.05). Differences in Tty, Ksk, and Fsk were not correlated with changes in plasma progesterone concentration. It is concluded that, during the L phase, a decreased thermal conductance in women exposed to a neutral environment allows the maintenance of a higher internal temperature.

Physical interaction between bacterial heat shock protein (Hsp) 90 and Hsp70 chaperones mediates their cooperative action to refold denatured proteins.

In eukaryotes, heat shock protein 90 (Hsp90) is an essential ATP-dependent molecular chaperone that associates with numerous client proteins. HtpG, a prokaryotic homolog of Hsp90, is essential for thermotolerance in cyanobacteria, and in vitro it suppresses the aggregation of denatured proteins efficiently. Understanding how the non-native client proteins bound to HtpG refold is of central importance to comprehend the essential role of HtpG under stress. Here, we demonstrate by yeast two-hybrid method, immunoprecipitation assays, and surface plasmon resonance techniques that HtpG physically interacts with DnaJ2 and DnaK2. DnaJ2, which belongs to the type II J-protein family, bound DnaK2 or HtpG with submicromolar affinity, and HtpG bound DnaK2 with micromolar affinity. Not only DnaJ2 but also HtpG enhanced the ATP hydrolysis by DnaK2. Although assisted by the DnaK2 chaperone system, HtpG enhanced native refolding of urea-denatured lactate dehydrogenase and heat-denatured glucose-6-phosphate dehydrogenase. HtpG did not substitute for DnaJ2 or GrpE in the DnaK2-assisted refolding of the denatured substrates. The heat-denatured malate dehydrogenase that did not refold by the assistance of the DnaK2 chaperone system alone was trapped by HtpG first and then transferred to DnaK2 where it refolded. Dissociation of substrates from HtpG was either ATP-dependent or -independent depending on the substrate, indicating the presence of two mechanisms of cooperative action between the HtpG and the DnaK2 chaperone system.

Conception rate of artificially inseminated Holstein cows affected by cloudy vaginal mucus, under intense heat conditions

The objective of this work was to obtain prevalence estimates of cloudy vaginal mucus in artificially inseminated Holstein cows raised under intense heat, in order to assess the effect of meteorological conditions on its occurrence during estrus and to determine its effect on conception rate. In a first study, an association was established between the occurrence of cloudy vaginal mucus during estrus and the conception rate of inseminated cows (18,620 services), raised under intense heat (mean annual temperature of 22°C), at highly technified farms, in the arid region of northern Mexico. In a second study, data from these large dairy operations were used to assess the effect of meteorological conditions throughout the year on the occurrence of cloudy vaginal mucus during artificial insemination (76,899 estruses). The overall rate of estruses with cloudy vaginal mucus was 21.4% (16,470/76,899; 95% confidence interval = 21.1-21.7%). The conception rate of cows with clean vaginal mucus was higher than that of cows with abnormal mucus (30.6 vs. 22%). Prevalence of estruses with cloudy vaginal mucus was strongly dependent on high ambient temperature and markedly higher in May and June. Acceptable conception rates in high milk-yielding Holstein cows can only be obtained with cows showing clear and translucid mucus at artificial insemination.

Water, energy and early postnatal growth in preterm infants.

Non-invasive methods, including stable isotope techniques, indirect calorimetry, nutritional balance and skinfold thickness, have given a new insight into early postnatal growth in neonates. Neonates and premature infants in particular, create an unusual opportunity to study the fluid and metabolic adaptation to extrauterine life because their physical environment can be controlled, fluid and energy balance can be measured and the link between metabolism and the energetics of their postnatal growth can be assessed accurately. Thus the postnatal time course of total body water, heat production, energy cost of growth and composition of weight gain have been quantified in a series of "healthy" low-birth-weight premature infants. These results show that total body water is remarkably stable between postnatal days 3-21. Energy expenditure and heat production rates increase postnatally from mean values of 40 kcal/kg/day during the first week to 60 kcal/kg/day in the third week. An apparent energy balance deficit of 180 kcal/kg can be ascribed to premature delivery. The cost of protein metabolism is the highest energy demanding process related to growth. The fact that nitrogen balance becomes positive within 72 h after birth places the newborn in a transitional situation of dissociated balance between energy and protein metabolism during early postnatal growth: skinfold thickness, dry body mass and fat decrease, while there is a gain in protein and increase in supine length. This particular situation ends during the second postnatal week and soon thereafter the rate of weight gain matches statural growth. The goals of the following review are to summarize data on total body water and energy metabolism in premature infants and to discuss how they correlate with physiological aspects of early postnatal growth.

Lämmöntalteenotto kosteasta poistoilmasta prosessiteollisuudessa

Tämän diplomityön päämääränä on tehdä prosessiteollisuuden tarpeisiin Excel-taulukkolaskentaohjelmassa toimiva putkilämmönsiirtimen mitoitusohjelma. Prosessiteollisuudessa lämmönvaihtimien toimintaympäristöt ja olosuhteet vaihtelevat merkittävästi ja niinpä jokaisen vaihtimen suunnittelu ja mitoitus on toteutettava tapauskohtaisesti. Työssä käsitellään rekuperatiivisen ristivirtaputkilämmönvaihtimen yleinen lämpötekninen mitoitus sisältäen putken sisäpinnalle tapahtuvan mahdollisen lauhtumisen. Mitoitettava vaihdinkoostuu pystysuorista putkista, joissa lämmin ja kostea ilma virtaa putkien sisäpuolella ja kylmä kuiva ilma vaippapuolella vaakasuoraan. Vaihdinmateriaalina käytetään ruostumatonta AISI 304 -tai haponkestävää AISI 316 terästä. Kuuman ilman tila vaihtelee tarkasteltavan kohteen mukaan. Paperiteollisuuden kuivausyksiköiltä poistuva ilma on usein lämmintä ja kosteaa, ja infrakuivaimilta poistuva ilma on kuumaa. Mitoitettavalle lämmönvaihtimelle tulevan kuuman ilman lämpötila tapauksesta riippuen voi vaihdella 30°C, maksimissaan +300°C:een saakka, vesisisällön ollessa välillä 0,010...0,200 kg/kg ki tai jopa tämän ylikin. Vaihtimen mitoitus perustuu energiataseyhtälöiden käyttöön. Laskennassa määritetään vaihtimen pintalämpötila sekä mahdollinen kostean ilman lauhtuminen putken sisäpinnalle. Lisäksi teoria käsittää molempien virtausten tilanmuutosten laskennan. Työssä on esitetty esimerkkilaskelma, jossa on laskettu ilma- kostea ilma lämmönsiirrinkonstruktio. Esimerkissä on tarkasteltu vaihtimen hyötysuhdetta, virtausten lämpö- ja kosteuskäyttäytymistä ulkoilman lämpötilan funktiona. Ohjelmasta saadaan tulostettua mitoitettavanvaihtimen dimensiot; putkien lukumäärät syvyys- ja pituussuunnassa sekä kokonaisputkilukumäärä, putkien väliset etäisyydet toisiinsa nähden sekä syvyys, että pituussuunnassa, putkipituus ja putken sisä- ja ulkohalkaisijat. Nämä tiedot suunnittelija itse syöttää ohjelmalle alkuarvoina. Laskettuna tietona ohjelma antaa molempien virtausten poistolämpötilat, kuuman ilman poistuvan absoluuttisen kosteuden, kondenssivesimäärän, vaihtimen tehon ja painehäviöt vaippa- ja putkipuolelle. Lisäksi ohjelma laskee kuuman ilman ominaisentalpiat vaihtimen sisään- ja ulostulossa. Tämä mahdollistaa ilman tilapisteiden piirtämisen Mollier-piirrokseen.

The epithelial sodium channel and the control of sodium balance.

Studies aiming at the elucidation of the genetic basis of rare monogenic forms of hypertension have identified mutations in genes coding for the epithelial sodium channel ENaC, for the mineralocorticoid receptor, or for enzymes crucial for the synthesis of aldosterone. These genetic studies clearly demonstrate the importance of the regulation of Na(+) absorption in the aldosterone-sensitive distal nephron (ASDN), for the maintenance of the extracellular fluid volume and blood pressure. Recent studies aiming at a better understanding of the cellular and molecular basis of ENaC-mediated Na(+) absorption in the distal part of nephron, have essentially focused on the regulation ENaC activity and on the aldosterone-signaling cascade. ENaC is a constitutively open channel, and factors controlling the number of active channels at the cell surface are likely to have profound effects on Na(+) absorption in the ASDN, and in the amount of Na(+) that is excreted in the final urine. A number of membrane-bound proteases, kinases, have recently been identified that increase ENaC activity at the cell surface in heterologous expressions systems. Ubiquitylation is a general process that regulates the stability of a variety of target proteins that include ENaC. Recently, deubiquitylating enzymes have been shown to increase ENaC activity in heterologous expressions systems. These regulatory mechanisms are likely to be nephron specific, since in vivo studies indicate that the adaptation of the renal excretion of Na(+) in response to Na(+) diet occurs predominantly in the early part (the connecting tubule) of the ASDN. An important work is presently done to determine in vivo the physiological relevance of these cellular and molecular mechanisms in regulation of ENaC activity. The contribution of the protease-dependent ENaC regulation in mediating Na(+) absorption in the ASDN is still not clearly understood. The signaling pathway that involves ubiquitylation of ENaC does not seem to be absolutely required for the aldosterone-mediated control of ENaC. These in vivo physiological studies presently constitute a major challenge for our understanding of the regulation of ENaC to maintain the Na(+) balance.

Simulation of Boundary Layers and Heat Transfer in the Entrance Region of Pipes

The study of fluid flow in pipes is one of the main topic of interest for engineers in industries. In this thesis, an effort is made to study the boundary layers formed near the wall of the pipe and how it behaves as a resistance to heat transfer. Before few decades, the scientists used to derive the analytical and empirical results by hand as there were limited means available to solve the complex fluid flow phenomena. Due to the increase in technology, now it has been practically possible to understand and analyze the actual fluid flow in any type of geometry. Several methodologies have been used in the past to analyze the boundary layer equations and to derive the expression for heat transfer. An integral relation approach is used for the analytical solution of the boundary layer equations and is compared with the FLUENT simulations for the laminar case. Law of the wall approach is used to derive the empirical correlation between dimensionless numbers and is then compared with the results from FLUENT for the turbulent case. In this thesis, different approaches like analytical, empirical and numerical are compared for the same set of fluid flow equations.

Energiankäytön tehostamispotentiaalit UPM-Pelloksen vaneritehtailla

UPM-Pelloksen vaneritehtaat muodostavat Euroopan suurimman vanerintuotantoyksiköntuotantokapasiteetilla mitattuna. Pelloksen vaneritehtailla on kolme eri tehdasta yhdellä tehdasalueella. Vaneritehtaiden viilunkuivaus on hyvin merkittävä primäärienergian kuluttaja. Tehtaiden prosessienergian saannista huolehtii Järvi-Suomen Voiman voimalaitos. Viilunkuivaajien poistokaasuista jalauhteista saadaan talteen merkittävästi sekundäärienergiaa. Sekundäärienergia kulutetaan pääosin hautomoaltaalla tukkien haudontaan. Tukkien haudonta pyritäänhoitamaan lähes kokonaan sekundäärienergialla. Primäärihöyryä tarvitaan altaalle kuitenkin huoltoseisakkien aikana. Tässä diplomityössä tutustutaan vanerin valmistuksen prosessiin Pelloksen vaneritehtailla. Työssä kartoitetaan tehtaiden prosessien, hautomoaltaan ja voimalaitoksen välisiä energiavirtauksia. Työn tarkoituksena on saada selville mahdollisia hyödyntämättömiä potentiaaleja tehtaiden energiankäytössä. Työssä pohditaan myös mahdollisia eri tapoja energiankäytön tehostukselle. Voimalaitoksen höyrykuorma on kuivauskoneiden kulutuksesta riippuen ajoittain voimakkaasti vaihtelevaa. Höyrykuorman vaihtelu aiheuttaa ongelmia voimalaitoksen tuotannolle. Työssä pohditaan höyrykuorman tasausmahdollisuutta muun muassa höyryakun avulla.

Flow phenomena, heat and mass transfer in microchannel reactors

The studies of flow phenomena, heat and mass transfer in microchannel reactors are beneficial to estimate and evaluate the ability of microchannel reactors to be operated for a given process reaction such as Fischer-Tropsch synthesis. The flow phenomena, for example, the flow regimes and flow patterns in microchannel reactors for both single phase and multiphase flow are affected by the configuration of the flow channel. The reviews of the previous works about the analysis of related parameters that affect the flow phenomena are shown in this report. In order to predict the phenomena of Fischer-Tropsch synthesis in microchannel reactors, the 3-dimensional computational fluid dynamic simulation with commercial software package FLUENT was done to study the flow phenomena and heat transfer for gas phase Fischer-Tropsch products flow in rectangular microchannel with hydraulic diameter 500 ¿m and length 15 cm. Numerical solution with slip boundary condition was used in the simulation and the flowphenomena and heat transfer were determined.

Chemical chaperones regulate molecular chaperones in vitro and in cells under combined salt and heat stresses.

Salt and heat stresses, which are often combined in nature, induce complementing defense mechanisms. Organisms adapt to high external salinity by accumulating small organic compounds known as osmolytes, which equilibrate cellular osmotic pressure. Osmolytes can also act as "chemical chaperones" by increasing the stability of native proteins and assisting refolding of unfolded polypeptides. Adaptation to heat stress depends on the expression of heat-shock proteins, many of which are molecular chaperones, that prevent protein aggregation, disassemble protein aggregates, and assist protein refolding. We show here that Escherichia coli cells preadapted to high salinity contain increased levels of glycine betaine that prevent protein aggregation under thermal stress. After heat shock, the aggregated proteins, which escaped protection, were disaggregated in salt-adapted cells as efficiently as in low salt. Here we address the effects of four common osmolytes on chaperone activity in vitro. Systematic dose responses of glycine betaine, glycerol, proline, and trehalose revealed a regulatory effect on the folding activities of individual and combinations of chaperones GroEL, DnaK, and ClpB. With the exception of trehalose, low physiological concentrations of proline, glycerol, and especially glycine betaine activated the molecular chaperones, likely by assisting local folding in chaperone-bound polypeptides and stabilizing the native end product of the reaction. High osmolyte concentrations, especially trehalose, strongly inhibited DnaK-dependent chaperone networks, such as DnaK+GroEL and DnaK+ClpB, likely because high viscosity affects dynamic interactions between chaperones and folding substrates and stabilizes protein aggregates. Thus, during combined salt and heat stresses, cells can specifically control protein stability and chaperone-mediated disaggregation and refolding by modulating the intracellular levels of different osmolytes.

Heat Transfer Analysis of the EPR Core Catcher Test Facility Volley

Uusi EPR-reaktorikonsepti on suunniteltu selviytymään tapauksista, joissa reaktorinsydän sulaa ja sula puhkaisee paineastian. Suojarakennuksen sisälle on suunniteltu alue, jolle sula passiivisesti kerätään, pidätetään ja jäähdytetään. Alueelle laaditaan valurautaelementeistä ns.sydänsieppari, joka tulvitetaan vedellä. Sydänsulan tuottama jälkilämpö siirtyyveteen, mistä se poistetaan suojarakennuksen jälkilämmönpoistojärjestelmän kautta. Suuri osa lämmöstä poistuu sydänsulasta sen yläpuolella olevaan veteen, mutta lämmönsiirron tehostamiseksi myös sydänsiepparin alapuolelle on sijoitettu vedellä täytettävät jäähdytyskanavat. Jotta sydänsiepparin toiminta voitaisiin todentaa, on Lappeenrannan Teknillisellä Yliopistolla rakennettu Volley-koelaitteisto tätä tarkoitusta varten. Koelaitteisto koostuu kahdesta täysimittaisesta valuraudasta tehdystä jäähdytyskanavasta. Sydänsulan tuottamaa jälkilämpöä simuloidaan koelaitteistossa sähkövastuksilla. Tässä työssä kuvataan simulaatioiden suorittaminen ja vertaillaan saatuja arvoja mittaustuloksiin. Työ keskittyy sydänsiepparista jäähdytyskanaviin tapahtuvan lämmönsiirron teoriaan jamekanismeihin. Työssä esitetään kolme erilaista korrelaatiota lämmönsiirtokertoimille allaskiehumisen tapauksessa. Nämä korrelaatiot soveltuvat erityisesti tapauksiin, joissa vain muutamia mittausparametreja on tiedossa. Työn toinen osa onVolley 04 -kokeiden simulointi. Ensin käytettyä simulointitapaa on kelpoistettuvertaamalla tuloksia Volley 04 ja 05 -kokeisiin, joissa koetta voitiin jatkaa tasapainotilaan ja joissa jäähdytteen käyttäytyminen jäähdytyskanavassa on tallennettu myös videokameralla. Näiden simulaatioiden tulokset ovat hyvin samanlaisiakuin mittaustulokset. Korkeammilla lämmitystehoilla kokeissa esiintyi vesi-iskuja, jotka rikkoivat videoinnin mahdollistavia ikkunoita. Tämän johdosta osassa Volley 04 -kokeita ikkunat peitettiin metallilevyillä. Joitakin kokeita jouduttiin keskeyttämään laitteiston suurten lämpöjännitysten johdosta. Tällaisten testien simulaatiot eivät ole yksinkertaisia suorittaa. Veden pinnan korkeudesta ei ole visuaalista havaintoa. Myöskään jäähdytteen tasapainotilanlämpötiloista ei ole tarkkaa tietoa, mutta joitakin oletuksia voidaan tehdä samoilla parametreilla tehtyjen Volley 05 -kokeiden perusteella. Mittaustulokset Volley 04 ja 05 -kokeista, jotka on videoitu ja voitu ajaa tasapainotilaan saakka, antoivat simulaatioiden kanssa hyvin samankaltaisia lämpötilojen arvoja. Keskeytettyjen kokeiden ekstrapolointi tasapainotilaan ei onnistunut kovin hyvin. Kokeet jouduttiin keskeyttämään niin paljon ennen termohydraulista tasapainoa, ettei tasapainotilan reunaehtoja voitu ennustaa. Videonauhoituksen puuttuessa ei veden pinnan korkeudesta saatu lisätietoa. Tuloksista voidaan lähinnä esittää arvioita siitä, mitä suuruusluokkaa mittapisteiden lämpötilat tulevat olemaan. Nämä lämpötilat ovat kuitenkin selvästi alle sydänsiepparissa käytettävän valuraudan sulamislämpötilan. Joten simulaatioiden perusteella voidaan sanoa, etteivät jäähdytyskanavien rakenteet sula, mikäli niissä on pienikin jäähdytevirtaus, eikä useampia kuin muutama vierekkäinen kanava ole täysin kuivana.