We investigate packet discarding schemes for TCP over ATM with GFR service. We test the throughput, fairness and goodput of two existing schemes, EPD and DFBA. In the simulation, we find that goodput is low when the network is incongestion. To provide a solution for this problem, we propose the SWFA(Selective Weighted Fair Allocation), which discards packets from selected sessions rather than by probability. Our results shows that SWFA achieves throughput and goodput enhancement over other schemes.

Objective of work: the aim of this study was to conduct a retrospective, quantitative, descriptive survey accompanied with a comparative statistical research, in which cases of patients with augmented renal clearance were examined and analyzed regarding the similarities and differences between them and their relevance for possible under-dosage of predominantly renally excreted drugs. Tasks: 1. to detect all cases of lower than 50 µmol/L Scr measurements and calculate possible ARC using Cockcroft-Gault equation in a defined period of time in a Lithuanian hospital in Kaunas. 2. To compare the performance of 3 different equations to distinguish the ARC as assessed by Cockcroft-Gault equation from non-ARC cases. 3. To analyze possible reasons associated with these ARC cases. 4. To search for the cases when predominantly renally excreted drugs were prescribed to these patients. / Tikslas darbo: Šio tyrimo tikslas buvo atlikti a posteriori, kiekybinį aprašomąjį tyrimą Kartu su lyginamosios statistinių tyrimų, kuriais atvejais pacientai, sergantys inkstų papildyta klirensas buvo išnagrinėti ir išanalizuoti apie panašumus ir skirtumus tarp jų ir jų svarbą galimo nepakankamo dozę daugiausia išsiskiria pro inkstus narkotikų. Uždaviniai: 1. Aptikti bet mažesnis negu 50 mmol / l SCR matavimų bylas ir apskaičiuoti galimą ARC naudojant Kokrofto-Gault lygtis nustatytą laiką, Lietuvos ligoninę Kaune. 2. Norėdami palyginti iš 3 skirtingų lygčių atskirti ARC, įvertintas Kokrofto-Gault lygtį kokybės iš ne ARC atvejais. 3. Išanalizuoti galimas priežastis, susijusias su šių ARC atvejais. 4. Norėdami ieškoti atvejai, kai daugiausia išsiskiria pro inkstus narkotikų buvo nustatyta, kad šiems pacientams.

Adefovir, an acyclic nucleotide reverse transcriptase inhibitor used to treat hepatitis B viral infection, is primarily eliminated renally through cooperation of glomerular filtration with active tubular transport. Nonalcoholic steatohepatitis is a variable in drug disposition, yet the impact on renal transport processes has yet to be fully understood. The goal of this study was to determine the effect of nonalcoholic steatohepatitis on the pharmacokinetics of adefovir in rats given a control or methionine and choline deficient diet to induce nonalcoholic steatohepatitis.

Worldwide, multiple countries are investing a great deal of time and energy towards developing a new class of technologically advanced nuclear reactors. These new reactors have come to be known as the Generation IV (Gen IV) class of nuclear reactors. Similarly to the other designs, the Gas Fast Reactor (GFR) has many advantages, such as electricity production at high efficiency, hydrogen production, minor actinide burning capabilities, etc. However, there are currently no immediate plans to build a GFR due to uncertainties regarding safety issues. The study conducted herein contains input techniques for the development of new neutronic and thermal hydraulic input decks for the United States (US) Department of Energy (DOE) GFR design. The Monte Carlo N-Particle (MCNP) and MELCOR codes are used to model neutronic and thermal hydraulic characteristics, respectively. These codes are used with the intention of gaining further insight into GFR design and steady state operating characteristics of the US DOE GFR. Descriptions of inputs for all input decks, along with the results of the execution of both input decks can be found in this thesis. Although many alterations are made to original design specifications, results found in this thesis support the design modifications that have been made. Results suggest that steady-state operation of the GFR is a plausible possibility, given the right conditions. The lack of design criteria for both the reflector and borated shield regions imposes a necessity of invention upon all those who seek to clarify design criteria for the US DOE GFR. Furthermore, resulting temperature profiles for the fuel, cladding and coolant give rise to the possibility of the design of a system, based on thermionic principles, that converts core thermal energy directly to electricity. Such a system is envisioned to provide electricity to a decay heat removal system and possibly increase plant efficiency.

Estimation of the glomerular filtration rate (GFR), accepted as one of the earliest and most sensitive indicators of renal dysfunction, can be determined in horses using standard techniques In adult horses and foals, renal dysfunction can occur as a secondary complication to gastrointestinal disorders, dehydration, septicemia, endotoxemia and nephrotoxic drug administration. Measurement of renal function is an important feature not only in the diagnosis, but also in the prognosis and management of renal disease. Commonly used drugs such as phenylbutazone and gentamicin can be highly nephrotoxic under certain conditions. Of particular concern are those drugs, including the aminoglycoside antibiotics, that are eliminated almost exclusively by the kidney. Knowledge of a patients renal status prior to treatment would direct efforts at; 1) restoring kidney function prior to protracted therapy with potentially damaging drugs, 2) adjusting the dose of a life-saving drug based on the magnitude of dysfunction, or 3) selecting a drug that is not dependant on renal function for elimination. such as endogenous or exogenous renal creatinine clearance. Unfortunately, these techniques can be time consuming, dangerous to perform on fractious patients, require trained personnel and are subject to errors most often associated with improper or incomplete urine collection. Recently, tests using iohexol, a radiographic contrast agent, have been developed to estimate the GFR in human beings, dogs and cats with results that have been validated by traditional standards. Most testing protocols require a single bolus injection of iohexol, followed by 2 or 3 blood samples obtained over a few hours. Compared to traditional testing methods, samples are easily and rapidly obtained making the testing procedure less stressful for the patient. A simple method to measure GFR in horses that does not require urine collection, would allow veterinarians in a clinical setting the ability to determine a patient's renal status easily and safely. The objectives of this study were; 1) model the pharmacokinetic profile of iohexol in horse foals, 2) compare creatinine clearance, an accepted standard for GFR determination in patients, with iohexol clearance, and 3) develop sampling parameters and calculation methods for a practical test, based on iohexol clearance, that compares favorably with creatinine clearance in horse foals. Iohexol concentration time data were best described using a 3-compartment open model. Mean creatinine clearance (2.17 ml/min/kg) and mean iohexol clearance (2.15 ml/min/kg) showed good agreement. In addition, GFR values for all foals using either method were within published reference ranges for this species. The results of this study indicate that a single intravenous injection of iohexol at a dose of 150 mg/kg, followed by collection of 2 serum samples at 4 and 6 hours post injection can be used to estimate the GFR in healthy horse foals. Mean corrected GFR value (CLpredicted) for 10 foals in this study was 2.15 ml/min/kg. / Master of Science

The glial cell-line derived neurotrophic factor (GDNF) and neurturin (NTN) belong to a structurally related family of neurotrophic factors. NTN exerts its effect through a multi-component receptor system consisting of the GDNF family receptor alpha 2 (GFRα2), proto-oncogene RET and/or NCAM. GFRα2 is spliced into at least three isoforms, GFRα2a, GFRα2b and GFRα2c. The present study investigated the expression and functional differences of GFRα2 isoforms. These receptor isoforms are differentially expressed in specific human brain regions. Using Neuro2A model, GDNF and NTN promote neurite outgrowth via GFRα2a and GFRα2c, but not GFRα2b. These GFRα2 isoforms regulate different early response genes when stimulated with GDNF and NTN. Interestingly, using co-expression models, GFRα2b inhibits ligand induced neurites outgrowth of GFRα2a and GFRα2c, and also the related receptor, GFRα1a. More intriguingly, ligands activated GFRα2b was also able to attenuate neurite extension induced by an unrelated stimulation using retinoic acid. MAPK activation induced by GDNF was not attenuated by GFRα2b in a co-expression model, while the early response genes expression profile (up-regulation of FosB) was similar to that induced by GFRα2b alone. This study suggest that GFRα2b is not merely a dominant negative isoform, but signals through a yet to be determined mechanism to antagonize and inhibit neuritogenesis. Together, these data suggest a new paradigm for the regulation of growth factor signaling and neurite outgrowth via an inhibitory splice variant of the receptor. / Singapore-MIT Alliance (SMA)

In adult horses and foals, renal dysfunction can occur as a secondary complication to gastrointestinal disorders, dehydration, septicemia, endotoxemia and nephrotoxic drug administration. Measurement of renal function is an important feature not only in the diagnosis, but also in the prognosis and management of renal disease. Commonly used drugs such as phenylbutazone and gentamicin can be highly nephrotoxic under certain conditions. Estimation of the glomerular filtration rate (GFR), accepted as one of the earliest and most sensitive assessments of renal function, can be determined in horses using standard techniques such as endogenous or exogenous renal creatinine clearance. These techniques can be time consuming, dangerous to perform on fractious patients, require trained personnel and are subject to errors most often associated with improper or incomplete urine collection. Recently, tests using iohexol, a radiographic contrast agent, have been developed to estimate the GFR in human beings, pigs, sheep, dogs, cats and horse foals with results that have been validated by traditional standards. Serum clearance of a substance that is freely filtered by the kidneys without tubular secretion or reabsorption, that is not protein bound, and that is not metabolized, is a measurement of glomerular filtration rate. Iohexol meets all of these requirements and thus its clearance from serum should accurately estimate GFR. Utilization of serum clearance studies for estimation of GFR provides a clinically feasible and reproducible method in order to measure GFR in horses. Other commonly used methods to assess renal function in horses are fraught with inherent and operator error. Serum clearance of iohexol does not necessitate collection of urine and has been shown to be a safe, reproducible method using collection of timed blood samples to assess renal function in humans and animals. The objectives of this project were 1) to determine a method of estimation of GFR based on serum clearance of a substance that meets the requirements of a marker for GFR, and 2) to make the method clinically applicable by developing a method using two blood samples to derive clearance and thus GFR in normal adult horses. Results of this study showed good agreement between GFR derived by exogenous creatinine clearance and serum clearance of iohexol. In addition, GFR values for all horses using either method were within published reference ranges for this species. The results of this study indicate that a single intravenous injection of iohexol at a dose of 150 mg/kg, followed by collection of 2 serum samples at 3 and 4 hours post injection can be used to estimate the GFR in healthy horses. / Master of Science

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24999号 / 医博第5033号 / 新制||医||1070(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 長船 健二, 教授 小林 恭, 教授 尾野 亘 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Bakgrund: Inom yrket som röntgensjuksköterska används dagligen kontrastmedel i samband med undersökningar. För att räkna ut hur mycket kontrastmedel som patienter ska erhålla för att förebygga kontrastinducerade njurskador används ekvationsformler för att räkna ut njurfunktionens glomerulära filtrationshastighet. Två formler som jämfördes var CKD-EPI och MDRD. Syfte: I denna litteraturstudie var syftet att jämföra vilken av de två mest förekommande ekvationsformler är mest optimal att använda för att räkna ut estimerat GFR. Metod: Denna studie genomfördes i form av en litteraturstudie där 11 artiklar kvalitetsgranskades och sammanställdes. Resultat: CKD-EPI-formeln uppvisade generellt bättre prestationsförmåga för noggrannhet, precision och avvikelse än MDRD-formeln för estimering av GFR. Dock hade båda ekvationerna svagheter och är inte universella då MDRD och CKD-EPI-formlerna inte är lämpliga att använda på alla individer. Slutsats: I dagsläget är CKD-EPI-formeln den som ter sig vara mest användbar, dock behövs det mer forskning för att kunna utveckla ekvationsformler som passar för alla typer av patienter. / Background: In the profession as radiology nurse contrast media is used daily in radiologic examinations. In order to determine the volume of contrast media that patients should be administered and to prevent contrast-induced nephropathy equation formulas are applied to calculate the kidney function glomerular filtration rate. Two formulas were compared the CKD-EPI and MDRD. Aim: In this literature study the aim was to compare which of the two most commonly used equation formulas is the most optimal for calculating estimated GFR. Methods: This study was conducted as a literature study, where 11 articles were quality assessed and compiled. Results: The CKD-EPI formula generally showed better performance for estimating GFR in accuracy, precision and bias than the MDRD formula. However, both equation formulas present inadequacies and are not universal as they are not applicable to all individuals. Conclusions: At the moment the CKD-EPI formula appears to be the most applicable, although more research is required in order to develop equation formulas which cater to all types of patients.

Bakgrund: För estimering av glomerulär filtrationshastighet (eGFR) behövs ett blodprov, såsom kreatinin eller cystatin C. En av röntgensjuksköterskans arbetsuppgifter är skattning av GFR innan jodkontrastmedel administreras, på grund av risken för njurbiverkningar. Hos äldre patienter är känsligheten för läkemedel påtaglig på grund av förändrad farmakokinetik. Osäkerhet råder om vilket blodprov som ger noggrannast eGFR.  Syfte: Syftet med studien var att genom litteraturgenomgång undersöka hur markörerna kreatinin respektive cystatin C skattar eGFR hos äldre patienter. Metod: Syftet besvarades av en litteraturstudie med resultat från åtta kvantitativa studier. De ingående studierna analyserades och sammanställdes. Databassökningarna utfördes i PubMed och Cinahl. Resultat: Resultatet visade att skattningarna av eGFR kunde skilja sig signifikant mellan kreatinin och cystatin C, medan andra gånger var de mer liknande. Vid stigande ålder ökade skillnaden mellan skattningarna av eGFR med de två markörerna. Konklusion:  Varken kreatinin eller cystatin C är optimalt. Delar av resultatet pekade mot att kombinationen kan vara en fördel. Mer forskning behövs inom området. / Background: When estimating glomerular filtration rate (eGFR), a blood test is required, such as creatinine or cystatin C. One of the radiographers' assignments is to estimate GFR before administering iodinated contrast agents, due to the risk of renal side effects. In elderly patients, the sensitivity to drugs is palpable due to altered pharmacokinetics. There is uncertainty about which blood test produces the most accurate eGFR. Aim: The aim was to investigate through a literature review how the markers creatinine and cystatin C estimate eGFR in elderly patients. Methods: The aim was answered by a literature study with results from eight quantitative studies, that were found in the databases PubMed and Cinahl. All included studies were analyzed and compiled. Results: The results showed that the estimates of eGFR could differ significantly between creatinine and cystatin C, while other times they were more similar. With an increasing age the two markers showed a larger difference in estimation of GFR. Conclusion: Neither creatinine nor cystatin C is optimal. Parts of the results indicated that the combination may be an advantage. More research is needed in this area.