Fate of cadmium in rat renal tubules: a micropuncture study.

Free-flow micropuncture was carried out in superficial nephrons of Munich-Wistar type rats infused acutely with Cd acetate (CdA) or Cd-DTPA (141 microM Cd). Fluid obtained from Bowman's space (BS) or end-proximal tubule sites was analyzed for Cd and inulin. The fluid/plasma Cd concentration ratio in BS averaged 0.2 and 1.0 during CdA and Cd-DTPA infusions, respectively. End-proximal tubule fractional excretion of Cd during CdA infusion averaged 0.34. Previous administration of CdA (1.0 mg/kg, 48 hr before micropuncture) increased the level of circulating Cd-metallothioneins, as measured by radioimmunoassay, but did not affect the luminal tubular uptake of Cd during CdA infusion. No net transepithelial movement of Cd-DTPA was measured. It is concluded that Cd ultrafiltered during inorganic Cd administration is taken up to a large extent by the convoluted part of proximal tubules.

Supplier Energy Audits in Thermal Power Plants

This master’s thesis handles an operating model for an electric equipment supplier conducted sale oriented energy audit for pumping, fan and other motor applications at power plants. The study goes through the largest factors affecting internal electricity use at a power plant, finds an energy audit –like approach for the basis of information gathering and presents the information needed for conducting the analysis. The model is tested in practice at a kraft recovery boiler of a chemical pulping mill. Targets chosen represent some of the largest electric motor applications in the boiler itself and in its fuel handling. The energy saving potential of the chosen targets is calculated by simulating the energy consumption of the alternatives for controlling the targets, and thereafter combining the information with the volume flow duration curve. Results of the research are somewhat divaricated, as all the information needed is not available in the automation system. Some of the targets could be simulated and their energy saving potential calculated quite easily. At some of the targets chosen the monitoring was not sufficient enough for this and additional measurements would have been needed to base the calculations on. In traditional energy audits, energy efficiency of pump and fan applications is not necessarily examined. This means that there are good possibilities for developing the now presented targeted energy audit procedure basis further.

Energiaa säästävä uusi viemäriveden pumppausteknologia

Pumppaaminen kuluttaa teollisuudessa huomattavan osan energiasta, joten siellä on myös merkittäviä säästömahdollisuuksia. Maailmanlaajuisesti pumppaus kuluttaa noin viidenneksen sähkömoottorien energiantarpeesta, ja tietyillä teollisuudentoimialoilla jopa yli 50%. Jätevedenpumppaus perustuu edelleenkin pääosin 50- ja 60- luvuilla kehitettyyn tekniikkaan, merkittäviä energiansäästöjä on mahdollista saavuttaa suhteellisen pienillä investoinneilla. Työn teoriaosassa käsitellään perusteet jätevedenkäsittelystä, ja viemäriputkiston rakenteesta. Pumppuja, sähkömoottoreita ja taajuusmuuttajia käsitellään laajemmin keskittyen niiden toimintaan ja toimintaa ohjaaviin teorioihin. Empiirisessä osassa tutkitaan uuden teknologian energiansäästöpotentiaalia erilaisilla mittauksilla, sekä mittausten pohjalta tehdyillä case-analyyseillä. Näitä analyysejä varten työn aikana kehiteltiin laskin, jolla voidaan arvioida energian kulutusta tunnetulle pumpulle, kun tiedetään haluttu toimintapiste. Työssä käsitelty uusi teknologia on mahdollisesti merkittävin uudistus viemäriveden pumppausteknologiaan taajuusmuuttajien käyttöönoton jälkeen. Teknologialla päästään eroon imukaivoista liki täysin, ja sitä kautta saadaan paremmin hallittua monia ongelmia kuten hajuhaittoja. Teknologian merkittävin hyöty on kuitenkin energiansäästö. Perinteisessä teknologiassa taajuusmuuttajat ovat olleet kannattavia, mikäli geodeettisen nostokorkeuden osuus on mahdollisimman pieni. Tyypillisessä uuden teknologian sovelluskohteissa geodeettinen nostokorkeus tulee yleensä olemaan pieni, joten uuden teknologian käyttöönoton kannattavuus on näissä kohteissa erityisen hyvä.

Developing of the Variable Speed Drive -control in simulated parallel pumping systems

This thesis presents briefly the basic operation and use of centrifugal pumps and parallel pumping applications. The characteristics of parallel pumping applications are compared to circuitry, in order to search analogy between these technical fields. The purpose of studying circuitry is to find out if common software tools for solving circuit performance could be used to observe parallel pumping applications. The empirical part of the thesis introduces a simulation environment for parallel pumping systems, which is based on circuit components of Matlab Simulink —software. The created simulation environment ensures the observation of variable speed controlled parallel pumping systems in case of different controlling methods. The introduced simulation environment was evaluated by building a simulation model for actual parallel pumping system at Lappeenranta University of Technology. The simulated performance of the parallel pumps was compared to measured values of the actual system. The gathered information shows, that if the initial data of the system and pump perfonnance is adequate, the circuitry based simulation environment can be exploited to observe parallel pumping systems. The introduced simulation environment can represent the actual operation of parallel pumps in reasonably accuracy. There by the circuitry based simulation can be used as a researching tool to develop new controlling ways for parallel pumps.

Mechanical circulatory support for destination therapy.

Patients with chronic heart failure who are not eligible for heart transplant and whose life expectancy depends mainly on the heart disease may benefit from mechanical circulatory support. Mechanical circulatory support restores adequate cardiac output and organ perfusion and eventually improves patients' clinical condition, quality of life and life expectancy. This treatment is called destination therapy (DT) and we estimate that in Switzerland more than 120 patients per year could benefit from it. In the last 10 years, design of the devices, implantation techniques and prognoses have changed dramatically. The key to successful therapy with a left ventricular assist device is appropriate patient selection, although we are still working on the definition of reliable inclusion and exclusion criteria and optimal timing for surgical implantation. Devices providing best long-term results are continuous flow, rotary or axial blood pumps implanted using minimally invasive techniques on a beating heart. These new devices (Thoratec HeartMate II and HeartWare HVAD) have only a single moving part, and have improved durability with virtually 10 years freedom from mechanical failure. In selected patients, the overall actuarial survival of DT patients is 75% at 1 year and 62% at 2 years, with a clear improvement in quality of life compared with medical management only. Complications include bleeding and infections; their overall incidence is significantly lower than with previous devices and their management is well defined. DT is evolving into an effective and reasonably cost-effective treatment option for a growing population of patients not eligible for heart transplant, showing encouraging survival rates at 2 years and providing clear improvement in quality of life. The future is bright for people suffering from chronic heart failure.

Evidence for hypothalamic ketone body sensing: impact on food intake and peripheral metabolic responses in mice.

Monocarboxylates have been implicated in the control of energy homeostasis. Among them, the putative role of ketone bodies produced notably during high-fat diet (HFD) has not been thoroughly explored. In this study, we aimed to determine the impact of a specific rise in cerebral ketone bodies on food intake and energy homeostasis regulation. A carotid infusion of ketone bodies was performed on mice to stimulate sensitive brain areas for 6 or 12 h. At each time point, food intake and different markers of energy homeostasis were analyzed to reveal the consequences of cerebral increase in ketone body level detection. First, an increase in food intake appeared over a 12-h period of brain ketone body perfusion. This stimulated food intake was associated with an increased expression of the hypothalamic neuropeptides NPY and AgRP as well as phosphorylated AMPK and is due to ketone bodies sensed by the brain, as blood ketone body levels did not change at that time. In parallel, gluconeogenesis and insulin sensitivity were transiently altered. Indeed, a dysregulation of glucose production and insulin secretion was observed after 6 h of ketone body perfusion, which reversed to normal at 12 h of perfusion. Altogether, these results suggest that an increase in brain ketone body concentration leads to hyperphagia and a transient perturbation of peripheral metabolic homeostasis.

Construção de equipamentos de refrigeração que permitem trabalhar com temperaturas de -40ºC ou -60ºC

In this article we describe the construction of two cooling systems with an immersion probe which will allow one to work at temperatures of either -40ºC or -60ºC. The two systems were constructed with readily available components and have been used daily for the last year in our laboratory to carry out reactions at low temperature or to cool down traps of vacuum pumps, reducing our need of dry-ice or liquid nitrogen.

Developing the environmental marketing of an industrial company

The objective of this study was to examine how the customers of Larox Flowsys value environmental issues and how environmental issues affect their purchasing behaviour. A comparison between Larox peristaltic pumps and competing pump brands and types was also made in order to find out whether LPP pumps possess some more environmentally beneficial features that other pumps do not have. Finally, if the answers to the first two research questions show that a need for a new marketing message does exist, then the final stage is to select the most appropriate environmental arguments for Larox Flowsys. The empirical data in the study was collected from several different sources, but the main sources were the customer interviews and the outsourced market research. The data was analysed mainly by using content analysis, but theme formation and quantification were also utilized. The results showed that the customers do not consider environmental issues as a main purchasing criterion, but they may well be the criterion that differentiates the product from competing ones. The comparison proved that LPP pumps do possess some significant environmental benefits over competing pumps and therefore, the prerequisite for the use of environmental arguments exists. The final stage in the study was to select the proper environmental arguments for Larox Flowsys.

Syrjäytystilavuuspumpun toiminnallisen välyksen säätömekanismin kehitys

Syrjäytystilavuuspumppua käytetään kuluttavien, syövyttävien, jähmeiden ja kiteytyvien väliaineiden pumppaukseen. Sähkömoottorin pyörittämä akseli puristaa rullan välityksellä letkun tiiviisti rungon sisäpintaa vasten työntäen samalla väliainetta edellään kulkiessaan letkua pitkin. Puristuksen jälkeen letku palautuu pyöreään muotoonsa muodostaen alipaineen pumpun imupuolelle. Nykyisen konstruktion iskunsäätö on toteutettu ruuvi-epäkeskomekanismilla, jolle haetaan vaihtoehtoja. Tässä työssä on tavoitteena kehittää syrjäytystilavuuspumpun iskunsäätömekanismista nykyistä konstruktiota yksinkertaisempi ja halvempi vaihtoehto. Työssä ideoidaan koneensuunnittelun perinteisin keinoin uusia ratkaisuvaihtoehtoja, joista kaksi valitaan jatkokehitykseen. Näistä kahdesta valitaan nykyiseen konstruktioon tehdyn vertailun jälkeen toinen lopulliseksi vaihtoehdoksi.

Role of Membrane Transporters, P-Glycoprotein and Mrp1, in The Placental Transfer of Drugs With Special Reference to Saquinavir and Quetiapine

Drug transporting membrane proteins are expressed in various human tissues and blood-tissue barriers, regulating the transfer of drugs, toxins and endogenous compounds into or out of the cells. Various in vitro and animal experiments suggest that P-glycoprotein (P-gp) forms a functional barrier between maternal and fetal blood circulation in the placenta thereby protecting the fetus from exposure to xenobiotics during pregnancy. The multidrug resistance-associated protein 1 (MRP1) is a relatively less studied transporter protein in the human placenta. The aim of this study series was to study the role of placental transporters, apical P-gp and basal MRP1, using saquinavir as a probe drug, and to study transfer of quetiapine and the role of P-gp in its transfer in the dually perfused human placenta/cotyledon. Furthermore, two ABCB1 (encoding P-gp) polymorphisms (c.3435C>T, p.Ile1145Ile and c.2677G>T/A, p.Ala893Ser/Thr) were studied to determine their impact on P-gp protein expression level and on the transfer of the study drugs. Also, the influence of the P-gp protein expression level on the transfer of the study drugs was addressed. Because P-gp and MRP1 are ATP-dependent drug-efflux pumps, it was studied whether exogenous ATP is needed for the function of ATP-dependent transporter in the present experimental model. The present results indicated that the addition of exogenous ATP was not necessary for transporter function in the perfused human placental cotyledon. Saquinavir and quetiapine were both found to cross the human placenta; transplacental transfer (TPTAUC %) for saquinavir was <0.5% and for quetiapine 3.7%. Pharmacologic blocking of P-gp led to disruption of the blood-placental barrier (BPB) and increased the placental transfer of P-gp substrate, saquinavir, into the fetal circulation by 6- to 8-fold. In reversed perfusions P-gp, MRP1 and possibly OATP2B1 had a negligible role in the fetal-to-maternal transfer of saquinavir. The TPTAUC % of saquinavir was about 100-fold greater from the fetal side to the maternal side compared with the maternal-to-fetal transfer. P-gp activity is not likely to modify the placental transfer of quetiapine. Higher P-gp protein expression levels were associated with the variant allele 3435T, but no correlation was found between the TPTAUC % of saquinavir and placental P-gp protein expression. The present results indicate that P-gp activity drastically affects the fetal exposure to saquinavir, and suggest that pharmacological blockade of the P-gp activity during pregnancy may pose an increased risk for adverse fetal outcome. The blockade of P-gp activity could be used in purpose to obtain higher drug concentration to the fetal side, for example, in prevention (to decrease virus transfer to fetal side) or in treating sick fetus.

Propulsor pneumático versátil e isento de pulsação para sistemas de análise em fluxo

Aquarium air pumps are proposed and evaluated as pneumatic liquid propulsion devices for flow injection and continuos flow analysis (FIA and CFA) systems. This kind of pump is widely available at a very low cost and it can sustain a pressure around of 4 psi (0.28 bar) indefinitely. By applying this air pressure onto a solution contained in a reservoir flask, it is possible to reach flow rates of up to 12.5 mL min-1 for circuits comprising reactors, made from 0.8 i.d. tubing with a length of 100 cm. The precise adjustment of flow rate below the maximum one can be made with a simplified needle valve or inserting in series a short length of capillary tube. The absence of flow pulsation is a definite advantage in comparison with peristaltic pumps, especially when amperometric detection is elected, as confirmed experimentally in FIA and CF applications.

Pientalojen ilmalämpöpumput sähköverkossa

Työssä tutkitaan ilmalämpöpumppujen kokonaisvaltaista vaikutusta sähköverkkoon. Tarkastelu aloitetaan lämpöpumppujen toiminnasta ja rakenteesta, josta jatketaan laitteen käytettävyyteen ja muiden lämmitysmenetelmien vertailuun. Sähköisten ominaisuuksien tarkastelussa pohditaan ilmalämpöpumppujen vaikutusta suomalaiseen sähköverkkoon muun muassa yleissähkötekniikan, taloudellisuuden ja energiatehokkuuden sekä häiriöiden kannalta. Tämä tutkielma rajoittuu pientaloihin, ja niihin asennettuihin ilma-ilmalämpöpumppuihin. Työn loppupäätelmänä on, että ilmalämpöpumppujen käytöstä ei juuri aiheudu vaikutuksia suomalaiseen sähköverkkoon. Suurimmat ilmalämpöpumppujen käytöstä syntyvät seuraukset kohdistuvat sähköverkkoyhtiöihin, joihin ilmalämpöpumput aiheuttavat taloudellisia menetyksiä. Suuret ja tulevaisuudessa kasvavat ilmalämpöpumppumäärät aiheuttavat sähköntuotantoon lisätehontarvetta huippukuorman aikaan. Toisaalta välitehoalueella tehontarve sekä energiankulutus pienenevät. Sähköverkoissa ei ole toistaiseksi havaittu ilmalämpöpumpuista johtuvia häiriöitä.

Sistema de alimentação gás-líquido para medidas de atividade catalítica

This note has as objective to present the advantages of the use of syringe-type pumps for the feeding of liquid reactants, together with mass flow controllers for gases, instead of the saturators, as it is generally accomplished. Among the advantages, the system with syringe pumps presents a greater flexibility in flow control as well as in composition compared with the system that uses saturator. In addition, the flow of the liquid reactants is known with precision in the syringe pump system.

Energy efficiency parameters in variable speed drives

The main purpose of this thesis is to measure and evaluate how accurately the current energy saving calculation in ABB’s new variable speed drive ACS850 works. The main topic of this thesis is energy-efficiency parameters. At the beginning of this thesis centrifugal pump, squirrel cage motor and variable speed drive, including some equations related to them, are being introduced. Also methods of throttling control and variable speed drive control of centrifugal pumps are being introduced. These subjects are introduced because the energy saving calculation in ACS850 is related to the centrifugal pumps usually driven by squirrel cage motors. The theory also includes short section about specific energy of pumping. Before measurements the current energy saving calculation of ACS850 is being introduced and analyzed. The measurements part includes introduction of measuring equipment, measurement results, summary and analysis of the measurements. At the end of this thesis a proposal for an improvement to the current energy saving calculation is being introduced and few proposals are made for new energy-efficiency parameters, which could be added to variable speed drives. At the end are also thoughts