The estimation of body fluids is a useful and common practice in the status assessment of diseasemechanisms and treatments. Electrical bioimpedance spectroscopy (EBIS) methods are non-invasive,inexpensive, and efficient alternatives for the estimation of body fluids. However, these methods areindirect, and their robustness and validity are unclear.Regarding the recording of measurements, a controversy developed regarding a spectrum deviationin the impedance plane, which is caused by capacitive leakage. This deviation is frequentlycompensated for by the extended Cole model, which lacks a theoretical basis; however, there is nomethod published to estimate the parameters. In this thesis, a simplified model to correct thedeviation was proposed and tested. The model consists of an equivalent capacitance in parallel withthe load.Subsequently, two other measurement artefacts were considered. Both artefacts were frequentlydisregarded with regard to total body and segmental EBIS measurements as their influence isinsignificant with suitable skin-electrode contact. However, this case is not always valid, particularlyfrom a textile-enabled measurement system perspective. In the estimation of body fluids, EBIS dataare fitted to a model to obtain resistances at low and high frequencies. These resistances can berelated to body fluid volumes. In order to minimise the influence of all three artefacts on theestimation of body fluids and improve the robustness and suitability of the model fitting the differentdomains of immittance were used and tested. The conductance in a reduced frequency spectrum wasproposed as the most robust domain against the artefacts considered.The robustness and accuracy of the method did not increase, even though resistances at low and highfrequencies can be robustly estimated against measurement artefacts. Thus, there is likely error in therelation between the resistances and volumes. Based on a theoretical analysis, state of the artmethods were reviewed and their limitations were identified. New methods were also proposed. Allmethods were tested using a clinical database of patients involved in growth hormone replacementtherapy. The results indicated EBIS are accurate methods to estimate body fluids, however they haverobustness limits. It is hypothesized that those limits in extra-cellular fluid are primarily due toanisotropy, in total body fluid they are primarily due to the uncertainty ρi, and errors in intra-cellularfluid are primarily due to the addition of errors in extracellular and total body fluid. Currently, theseerrors cannot be prevented or minimised. Thus, the limitations for robustness must be predicted priorto applying EBIS to estimate body fluids. / <p>QC 20130917</p>

No description available.

No description available.

Thesis (Ph. D.)--University of Missouri-Columbia, 2005. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on October 19, 2007) Vita. Includes bibliographical references.

AIM: To contrast the effects of various modifications of body fluid volumes on thirst as reported by healthy volunteers. METHODS: Ten male volunteers aged between 19 and 37 years (mean 22 years) underwent four experiments each, which comprised infusion of 400-800 mL of acetated Ringer’s solution and intake of 600 mL of tap water. Half of the experiments were preceded by volume depletion (median 1.7 L) with furosemide. A visual analogue scale (0-100 mm) was used to assess perceived thirst during each experiment. RESULTS: Volume depletion (P &lt; 0.001) and tap water (P &lt; 0.03) both affected thirst by 13 mm per L of fluid, whereas spontaneous diuresis and infusion of Ringer’s acetate did not significantly change the thirst rating (multiple regressions). More detailed analyses showed that the volume depletion increased the median (25th-75th percentiles) thirst rating from 28 mm (21-43) to 59 mm (46-72, P &lt; 0.001) while no change occurred in those who were only slightly thirsty (&lt; 30 mm) before the volume depletion began. Ringer’s solution alleviated thirst in those who were very thirsty, but tended to increase thirst in the volunteers who were not thirsty before the infusion. Similarly, hydration with tap water decreased thirst (by 24 mm, P &lt; 0.04) in those who were thirsty (&gt; 60 mm) while the others reported no change. CONCLUSION: The change in thirst rating during volume depletion, administration of Ringer’s acetate, and ingestion of tap water were all dependent on the thirst rating obtained when the manipulation of the body fluid volume was initiated.

published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

No description available.

It has been previously shown that SERS provides a rapid, confirmatory technique for the detection of blood, one of the most commonly found body fluids at a crime scene, from samples extracted with 1 µL of 50% acetic acid and placed on Au nanoparticle substrates developed by this laboratory. In recent results, the SERS spectra of blood extracted using a 50% acetic acid procedure is distinguished from 30 other reddish-brown stains (RBS) that do not contain blood, with 100% sensitivity and specificity using a partial least squares discriminant analysis (PLS-DA). A blind study was performed and 12 blinded samples were tested using the statistical method. All stains were identified as blood or non-blood with 100% accuracy. While peripheral blood and menstrual blood share many components, the complexity of menstrual blood is further enhanced by the addition of vaginal secretions. Further demonstrating SERS specificity, differential extraction procedures using water and acetic acid allow peripheral and menstrual blood to be distinguished. Given the sensitivity of SERS to identify bloodstains invisible to the naked eye, it is important to establish what limitations luminol might impose for SERS identification of bloodstains. SERS sensitivity allows blood diluted by a factor of at least 100 to be detected in the presence of undiluted luminol when using the acetic acid procedure. Current results demonstrate that the SERS detection limit is at least 103 diluted bloodstains when 1% luminol solutions, capable of producing the bright blue glow, are employed. In sexual assault cases, it may be necessary to identify the presence of semen prior to DNA analysis. Sexual assault cases may also require the identification of the presence of vaginal fluid in certain scenarios. A stain extraction method prior to SERS analysis was optimized for both semen and vaginal fluid by testing different extraction procedures with water and acetic acid. In semen, the acetic acid procedure was found to produce a signal intensity 4 times that of the water extraction procedure. Preliminary results show that for vaginal fluid, the water procedure was found to produce a SERS signal intensity more than 3 times that of the acetic acid procedure. Using differing solubilities of the chemical components of these body fluids, mixture deconvolution has been shown to be possible. The analysis of four swab types for SERS acquisition are compared in order to determine the optimal swab types for field collection of various trace body fluids. SERS analysis of trace body fluids for forensic work is a minimally destructive technique that can be applied for rapid and easy examination of evidence. The high sensitivity and specificity of SERS provides a robust spectroscopic technique for the rapid detection and identification of trace body fluids.

In theory, RNA expression patterns, including the presence and relative abundance of particular RNA species, provide cell and tissue specific information that could be of use to forensic scientists. An mRNA based approach could allow the facile identification of the tissue components present in a body fluid stain and conceivably could supplant the battery of serological and biochemical tests currently employed in the forensic serology laboratory. Some of the potential advantages include greater test specificity, and the ability to perform simultaneous analysis using a common assay format for the presence of all body fluids of forensic interest. In this report, the recovery and stability of RNA in forensic samples was evaluated by conducting an in-depth study on the persistence of RNA in biological stains. Stains were prepared from blood, saliva, semen, and vaginal secretions, and were exposed to a range of environmental conditions so that the affects of different light sources, temperatures, and environments could be assessed. Using the results from quantitation and sensitivity studies performed with pristine forensic stains, the RNA stability of samples which were collected over a period of 1 day to 1 year for blood, saliva, and vaginal secretion stains and for up to 6 months for semen stains were analyzed. The extent of RNA degradation within each type of body fluid stain was determined using quantitation of total RNA and reverse transcriptase polymerase chain reaction (RT-PCR) with selected housekeeping and tissue-specific genes. The results show that RNA can be recovered from biological stains in sufficient quantity and quality for mRNA analysis. The results also show that mRNA is detectable in samples stored at room temperature for at least one year, but that heat and humidity appear to be very detrimental to the stability of RNA.

Thesis (MCur)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Motivation. Homeostasis is a dynamic and balanced process that must be maintained in order to for health to be sustained (Scales & Pilsworth, 2008:50-57). In critically illness, homeostasis is disrupted and along with inadequate tissue perfusion potentially leads to multiple organ failure (Elliot, Aitken & Chaboyer, 2007:437). The fluid balance of a patient is essential for preserving homeostasis and to maintain optimal tissue perfusion, thus monitoring fluid balance plays an important role in the managing a critically ill patient. Current literature and best nursing practice emphasise the importance of accurate and correct fluid balance monitoring in critically ill patients including recording fluid intake and output on a purpose designed fluid balance sheet. Research has shown that the patient’s outcome after critical illness is influenced by the fluid balance management including fluid balance monitoring (Vincent, Sakr, Sprung, Ranieri, Reinhart, Gerlach, Moreno, Carlet, Le Gall & Payen, 2006:344-353), while several studies have questioned accuracy of fluid balance calculation in various acute care settings (Johnson & Monkhouse, 2009:291; Smith, Fraser, Plowright, Dennington, Seymour, Oliver & MacLellan, 2008:28-29). In an informal audit performed in a local critical care unit, seven out of ten fluid balances were incorrectly calculated. Clinical experience of nurses’ inattention to fluid balance monitoring, together with the informal audit data, reveals that fluid balance monitoring is generally not performed correctly or accurately by nurses working in critical care units. The aim of the study was to describe the perspectives and practices of registered nurses in critical care units with regard to fluid balance monitoring. Methods. A quantitative approach in the form of an audit was applied to establish the current practice of fluid balance monitoring. A survey was conducted among registered nurses to gain insight into their perspectives and knowledge of fluid balance monitoring. The sample for the audit was drawn from fluid balance records, which met the study inclusion criteria. The survey was conducted with a sample of participants from registered nurses in critical care units from a particular hospital group, in compliance with the inclusion criteria. The researcher collected the data using a purpose designed audit tool and questionnaire. Results. The audit revealed that 90 % of the sampled fluid balance records were inaccurate (tolerated deviation 0-10ml) and 79% were inaccurate if a deviation of 50ml would be tolerated. Furthermore the inaccuracy in calculation was larger in patients whoreceived diuretics. The questionnaire data revealed that registered nurses considered fluid balance monitoring as an important part of patient nursing care and were aware that inaccuracy can pose a risk to the patient. The nurses feel responsible for performing fluid balance monitoring. In addition the nurses gave recommendations for the practice. Discussion. The results of this study are similar to other studies done internationally. The nurses are aware of the importance of the fluid balance, and recognise the inaccuracies. With our limited resources, both financial and in terms of nursing staff, the solutions have to be very basic and practical. Key words: fluid balance, critical care, accuracy and auditing, best practice / AFRIKAANSE OPSOMMING: Motivering. Homeostase is ’n dinamiese en gebalanseerde proses wat onderhou moet word vir gesondheid om handhaaf te word (Scales & Pilsworth, 2008:50-57). Onder toestande van kritieke siekte, word homeostase onderbreek en kan dit saam met onvoldoende weefselperfusie moontlik tot veelvuldige orgaanmislukking lei (Elliot, Aitken & Chaboyer, 2007:437). Die vloeistofbalans van ’n pasiënt is van die uiterste belang vir die preservering van homeostase en om optimale weefselperfusie te onderhou, en dus speel die monitering van vloeistofbalans ’n belangrike rol in die bestuur van die pasiënt wat kritiek siek is. Die huidige literatuur en beste verpleegkundige praktyk beklemtoon die belangrikheid van akkurate en korrekte vloeistofbalansmonitering in pasiënte wat kritiek siek is, insluitend die aantekening van vloeistofinname en -afskeiding op ’n vorm wat vir die doel pasgemaak is. Navorsing het getoon dat die pasiënt se uitkoms ná kritiese siekte deur vloeistofbalansbestuur, insluitend vloeistofbalansmonitering, beïnvloed word (Vincent, Sakr, Sprung, Ranieri, Reinhart, Gerlach, Moreno, Carlet, Le Gall & Payen, 2006:344-353), terwyl verskeie studies die akkuraatheid van die vloeistofbalansberekening in ’n verskeidenheid kritiekesorgeenhede bevraagteken het (Johnson & Monkhouse, 2009:291; Smith, Fraser, Plowright, Dennington, Seymour, Oliver & MacLellan, 2008:28-29). In ’n informele oudit wat in ’n plaaslike kritiekesorgeenheid uitgevoer is, is daar gevind dat sewe uit tien vloeistofbalanse verkeerdelik bereken is. Kliniese ervaring van verpleërs se agtelosigheid met betrekking tot vloeistofbalansmonitering, tesame met die data vanuit die informele oudit, wys dat vloeistofbalansmonitering oor die algemeen nie korrek of akkuraat deur verpleërs in die kritiekesorgeenheid uitgevoer word nie. Die doelwit van hierdie studie was om die perspektiewe en praktyke van geregistreerde verpleërs in kritiekesorgeenhede met betrekking tot vloeistofbalansmonitering te beskryf. Metodes. ’n Kwantitatiewe benadering in die vorm van ’n oudit is gebruik om die huidige praktyk van vloeistofbalansmonitering te bepaal. ’n Opname is onder geregistreerde verpleërs gedoen om insig te bekom oor hulle perspektiewe oor en kennis van vloeistofbalansmonitering. Die steekproef vir die oudit is geneem uit vloeistofbalansrekords wat aan die studiekriteria voldoen het. Die opname is gedoen onder ’n steekproef van geregistreerde verpleërs in ’n kritiekesorgeenheid van ’n spesifieke hospitaalgroep, in ooreenstemming met die insluitingskriteria. Die navorser het die data met ’n pasgemaakte ouditinstrument en vraelys versamel. Resultate. Die oudit het gewys dat 90% van die vloeistofbalansrekords in die steekproef onakkuraat was (toleransie verskil 0-50ml) en 79% was onakkuraat als een verskil van 50 ml was tolereer. Verder was die onakkuraatheid in die berekenings groter in pasiënte wat urineermiddels ontvang het. Die data vanaf die vraelys het gewys dat geregistreerde verpleërs vloeistofbalansmonitering as ’n belangrike deel van die verpleging van ’n pasiënt beskou en daarvan bewus is dat onakkuraatheid ’n risiko vir die pasiënt kan inhou. Die verpleërs voel daarvoor verantwoordelik om die vloeistofbalansmonitering uit te voer. Hulle het ook aanbevelings vir die praktyk gemaak. Bespreking. Die resultate van hierdie studie is baie soortgelyk aan dié van ander internasionale studies. Die verpleërs is bewus van die belangrikheid van die vloeistofbalans en is bewus van die onakkuraathede. Met ons beperkte hulpbronne, beide finansieel en in terme van verpleegpersoneel, is dit noodsaaklik dat die oplossings baie basies en prakties is. Sleutelwoorde: vloeistofbalans, kritieke sorg, akkuraatheid en ouditering, beste praktyk