bluuebunny/crossref_metadata_2025 huggingface dataset:
Go with the Flow: Particle Systems for Program Modeling in High-Rise Buildings
Authors: (Junno) Yaniv Ophir
Published: September 2008

This paper revisits the particle flow system, a time-based computational tool, which has received a lot of attention from the early pioneers of digital architecture. The use of particle flow systems in architecture enables designers to materialize what they term as site forces which can later be formalized into a building. The methods offered by various designers for using particle flow systems in architecture have kept the discourse purely formal by focusing on the exterior and neglecting the interior. This paper offers a different way of using and conceptualizing particle flow systems in architecture. Shifting the emphasis from the formal, the paper aims to show the potential of using particle flow systems as a parametric model for exploring the spatial organization of an architectural program. This paper also illustrates the application of the proposed computational model, i.e., the particle flow system, by using a case study – the design of a high-rise building in downtown Tel Aviv, Israel.
Insulin resistance and obesity in childhood
Authors: Chiarelli Francesco , Marcovecchio Maria Loredana
Published: September 2008

Childhood obesity is a significant health problem that has reached epidemic proportions around the world and is associated with several metabolic and cardiovascular complications. Insulin resistance is a common feature of childhood obesity and is considered to be an important link between adiposity and the associated risk of type 2 diabetes and cardiovascular disease. Insulin resistance is also a key component of the metabolic syndrome, and its prevalence in the paediatric population is increasing, particularly among obese children and adolescents. Several factors are implicated in the pathogenesis of obesity-related insulin resistance, such as increased free fatty acids and many hormones and cytokines released by adipose tissue.

Valid and reliable methods are essential to assess the presence and the extent of insulin resistance, the associated risk factors and the effect of pharmacological and lifestyle interventions. The two most common tests to assess insulin resistance are the hyperinsulinemic euglycemic clamp and the frequently sampled i.v. glucose tolerance test utilizing the minimal model. However, both these tests are not easily accomplished, are time consuming, expensive and invasive. Simpler methods to assess insulin resistance based on surrogate markers derived from an oral glucose tolerance test or from fasting insulin and glucose levels have been validated in children and adolescents and widely used.

Given the strong association between obesity, insulin resistance and the development of metabolic syndrome and cardiovascular disease, prevention and treatment of childhood obesity appear to be essential to prevent the development of insulin resistance and the associated complications.
Multiple endocrine neoplasia type 2A in two families with the familial medullary thyroid carcinoma associated G533C mutation of the RET proto-oncogene
Authors: Peppa Melpomeni , Boutati Eleni , Kamakari Smaragda , Pikounis Vasilios , Peros George , Panayiotides Ioannis G , Economopoulos Theofanis , Raptis Sotirios A , Hadjidakis Dimitrios
Published: September 2008

Introduction

Multiple endocrine neoplasia type 2A (MEN2A) is an autosomal dominant hereditary disorder, associated with a cluster of germline gain-of-function mutations of the RET proto-oncogene (RET), mainly in exons 10–15. The G533C mutation in exon 8 of the RET is rare and has been mainly related to the familial medullary thyroid carcinoma.

Patients-methods

We describe the RET G533C mutation in exon 8 of the RET in two unrelated female index patients, with MEN2A phenotype, consisting of pheochromocytoma which was the presenting feature and medullary thyroid carcinoma. In addition, 12 family members were also studied. DNA extraction, PCR, and sequencing of RET was performed in exons 7–19 and 21, following standard procedures.

Results

The mutation was found in both index patients and in 6 out of 12 family members (50%). Three of them were biochemically affected with histologically proven medullary thyroid carcinoma in two of them while there are no certain clues regarding the other three members as they declined further evaluation.

Conclusion

Patients with MEN2A should be also searched in exon 8 while positive carriers of this mutation should be screened annually for pheochromocytoma or other components of the syndrome.
Spatiotemporal expression of transcriptional regulators in concert with the maternal-to-embryonic transition during bovine in vitro embryogenesis
Authors: Vigneault Christian , McGraw Serge , Sirard Marc-Andre
Published: September 2008

Cleavage-stage bovine embryos are transcriptionally quiescent until they reach the 8- to 16-cell stage, and thus rely on the reserves provided by the stored maternal mRNAs and proteins found in the oocytes to achieve their first cell divisions. The objective of this study was to characterize the expression and localization of the transcriptional and translational regulators, Y box binding protein 2 (YBX2), TATA box-binding protein (TBP), and activating transcription factor 2 (ATF2), during bovine early embryo development. Germinal vesicle (GV)- and metaphase II (MII)-stage oocytes, as well as 2-, 4-, 8-, 16-cell-stage embryos, morula, and blastocysts, producedin vitrowere analyzed for temporal and spatial protein expression. Using Q-PCR,ATF2mRNA expression was shown to remain constant from the GV-stage oocyte to the four-cell embryo, and then decreased through to the blastocyst stage. By contrast, the protein levels of ATF2 remained constant throughout embryo development and were found in both the cytoplasm and the nucleus. Both TBP and YBX2 showed opposite protein expression patterns, as YBX2 protein levels decreased throughout development, while TBP levels increased through to the blastocyst stage. Immunolocalization studies revealed that TBP protein was localized in the nucleus of 8- to 16-cell-stage embryos, whereas the translational regulator YBX2 was exclusively cytoplasmic and disappeared from the 16-cell stage onward. This study shows that YBX2, TBP, and ATF2 are differentially regulated through embryo development, and provides insight into the molecular events occurring during the activation of the bovine genome during embryo developmentin vitro.
New results in the research of the biomechanics of the venous system
Authors: Molnár Andrea Ágnes , Apor Asztrid , Kiss Róbert Gábor , Préda István , Monos Emil , Bérczi Viktor , Nádasy György László
Published: September 2008

Az ember nem feltételezett fölegyenesedése jelentős evolúciós kihívást jelenthetett a földi gravitációs térben. Az ortosztatikus toleranciáért felelős mechanizmusok jelentős része a vénás rendszerhez kapcsolódik. Munkánkban az ezzel kapcsolatos, újabban feltárt biomechanikai jelenségek élettani és kórélettani jelentőségét tárgyaljuk. Kiemelten foglalkozunk egy viszonylag elhanyagolt területtel, a vénák falának biomechanikai tulajdonságaival. Ezek érterületenként eltérőek, de változnak a kor, a nem, a testtömeg és talán még egyéb antropológiai szempontok függvényében is. A vénák antigravitációs adaptív viselkedése többszintű, a vénafal mindhárom rétegét érintő szabályozómechanizmusok összehangolt működésének eredménye, amelyek rövid távú és hosszú távú alkalmazkodást biztosítanak. Lokális miogén és humorális mechanizmusok, a távolabbi szervek-szövetek felől pedig hormonális és idegi mechanizmusok együttesen szabályozzák a vénák adaptív viselkedését. Ezek hosszabb távon hatva a vénafal strukturális és funkcionális átépüléséhez (újabban használatos szakkifejezéssel: remodelingjéhez) vezetnek. A vénák patológiás elváltozásainak jelentős része kóros vénafal-átépüléssel jár. Hemodinamikai tényezők (nyomás és áramlás) indukálta adaptív mechanizmusok, de gyulladásos folyamatok is részt vehetnek a vénafal kóros átépülésében, megváltoztatva ezáltal a vénafal biomechanikai viselkedését. Ez circulus vitiosusként hozzájárul a vénás kórfolyamat fenntartásához, illetve progressziójához. Az újabb noninvazív humán biomechanikai technikák lehetőségeit jelzi, hogy vénás betegség szempontjából klinikailag már, illetve még aszimptomatikus személyek vizsgálatával munkacsoportunk is ki tudott mutatni kóros vascularis biomechanikai viselkedést. Így a vénák biomechanikájának diagnosztikus célú vizsgálata nemcsak a patomechanizmus feltárásához nyújthat segítséget, hanem a vénás betegségek korai felismerésében és következményeinek objektív követésében is szerepet játszhat. A kóros jelek korai felismerése lehetőséget ad arra, hogy a vénák biomechanikai adaptációs folyamataira ható preventív és terápiás eljárásokkal csökkentsük ennek a ma még igen elterjedt népbetegségcsoportnak az előfordulási gyakoriságát, valamint az általa okozott emberi szenvedést és anyagi kárt.
Selenium deficiency and infertility. Andrological aspects
Authors: Szöllősi János , Závaczki Zoltán , Pál Attila
Published: September 2008

A szelén abszolút hiánya az emberi szervezetben igen ritkán következik be, de a szuboptimális napi szelénbevitel miatt kialakuló relatív szelénhiány észrevétlenül is kialakulhat. A szelénhiány számos ismert következménye közül a jelen közleményben a szerzők a férfifertilitásra gyakorolt hatásokat emelik ki, összefoglalva a legfontosabb biokémiai, állatkísérletes és humán vonatkozásokat.
Haplogroup analysis of vitamin-K epoxide reductase (VKORC1) gene: novel element in the optimization of anticoagulant therapy
Authors: Sipeky Csilla , Melegh Béla
Published: September 2008

A warfarin és az acenokumarolok a leggyakrabban alkalmazott antikoagulánsok, amelyek szűk terápiás tartománnyal rendelkeznek, a hatásos dózis pedig populáción belül és egyénenként is nagy változatosságot mutat. A kumarinok a K-vitamin-epoxidreduktáz enzim (VKOR) gátlásán keresztül akadályozzák meg a koagulációt. Az enzimet kódoló VKORC1 gén mutációi jelentősen befolyásolják a kumarinok iránti érzékenységet. A VKORC1 gén genetikai variabilitását a *2, *3 és a *4 haplotípusok fedik le a kaukázusi populációban. Antikoaguláns kezelésben részesülő betegek bemutatásán keresztül összefoglaló tanulmányban ismertetjük a VKORC1 gén haplotípusának variabilitását. Munkánkban 28, klinikailag nem szokványos antikoaguláns választ produkáló beteget karakterizáltunk a VKORC1 G-1639A, G9041A és C6009T polimorfizmusokra. Molekuláris módszerként PCR-RFLP technikát és direkt szekvenálást alkalmaztunk. Betegpopulációnkban sikerült kimutatni VKORC1 *1*2, *2*2, *2*3, *1*4, *2*4 és *3*4 haplotípusokat. Vizsgált betegeink körében előfordult a VKORC1 gén haplotípusa alapján közepes dózisigényű (4,9±0,2 mg/nap) A/B haplocsoportú (a vizsgált betegek 61%-a) és magas dózisigényű (6,2±0,3 mg/nap) B haplocsoportú (25%) beteg is. Az antikoaguláns terápia vérzéses szövődményeinek megelőzésében fontos az alacsony warfarindózisú (2,7±0,2 mg/nap) A haplocsoportba tartozó betegek (esetünkben 14%) diagnosztizálása. Eredményeink mutatják, hogy a haplocsoport-vizsgálat segíti a megfelelő szintű véralvadásgátláshoz szükséges gyógyszerdózis meghatározását és a végzetes vérzési epizódok elkerülését.
The combined antihypertensive and antilipid treatment as a polypill therapeutic preventive strategy is a mean column of hypertensive patients with high cardiovascular risk
Authors: Kékes Ede
Published: September 2008

A magasvérnyomás-betegség az egyik leggyakoribb betegségforma, amely önmagában is cardiovascularis rizikófaktor Európa és Amerika civilizált országaiban. A hypertoniás betegek 40–50%-ában egyéb rizikófaktorok is társulnak a betegséghez, mint dohányzás, dyslipidaemia, szénhidrátanyagcsere-zavar, metabolikus szindróma vagy éppen 2-es típusú diabetes mellitus. Ezeknél a magas rizikójú betegeknél az optimális kezelés megoldása nem egyszerű feladat, és a célérték elérése monoterápiával csaknem lehetetlen. Az utóbbi években kiderült, hogy a vérnyomáscsökkentés és a kóros lipidprofil-normalizálás együttes megvalósítása igen nagy jelentőségű az atheroscleroticus szövődmények megelőzése terén. Ehhez két-három vagy több gyógyszer együttes adására van szükség.Mi elindítottunk egy nyitott vizsgálatot mintegy 1000, nagy rizikójú hypertoniás betegnél, akiknél a magas vérnyomás mellett dyslipidaemiát, visceralis obesitast, metabolikus szindrómát vagy 2-es típusú diabetest igazoltak. A polipill típusú kezelési stratégiánk során ACE-inhibitort (lisinopril), kalciumantagonistát (amlodipin), statint (atorvastatin) és szükség szerint antithrombocyta-kezelést adtunk.
Intracardiac echocardiography guided cardiac tumormass biopsy
Authors: Kutyifa Valentina , Merkely Béla , Pozsonyi Zoltán , Hosszú Krisztina , Szilágyi Szabolcs , Balázs György , Tóth Attila , Sármán Pál , Gellér László
Published: September 2008

A primer cardialis tumorok ritka kórképek, amelyek sokszor sokáig tünetmentesek maradhatnak. Az áttétet még nem adó tumor kuratív terápiája a reszekció és a kombinált célzott kemoterápiás kezelés. A legtöbb olyan esetben azonban, amikor a terime már nem reszekálható, szükséges lehet a biopszia elvégzése a pontos szövettani diagnózis felállításához, valamint a terápiás terv kidolgozásához. A következőkben egy 56 éves nőbeteg esetét ismertetjük, akinél ismétlődő pericardialis fluidum kivizsgálása során derült fény az intracardialis tumormassza jelenlétére. Az elváltozás nonreszekábilisnak bizonyult, így biopsziát és célzott kemoterápiás kezelést terveztünk. A beteg kisebb megterhelése érdekében a tumormassza-biopsziát nem thoracotomiából, hanem percutan katéteres módszerrel végeztük el. A biopszia pontosságát egy új módszer, az intracardialis ultrahang biztosította. Esetünk jól mutatja, hogy az intracardialis ultrahang vezérelte biopszia hatékony, biztonságos módszer, amely segíti a pontos mintavételt, és a beavatkozás biztonságosságát is növelheti.
Efficacy of the emergency unit’s filter function in patients with psychiatric symptoms
Authors: Ekler Katalin , Magos Mária , Szélig György , Gazdag Gábor
Published: September 2008

Az utóbbi években egyre több kórházban létrehozott sürgősségi részlegeknek/osztályoknak alapvető funkciója a kórházba érkező betegek elsődleges vizsgálata, szükség esetén sürgősségi ellátása, majd – amennyiben a beteg kórházi kezelést igényel – a megfelelő osztályra irányítása.
Célkitűzés:
Munkánkban arra kerestük a választ, hogy a sürgősségi részlegen végzett elsődleges vizsgálatok közül pszichiátriai sürgősséginek véleményezett esetekben a későbbi vizsgálatok milyen arányban erősítették meg az elsődleges diagnózist. Az eltérően diagnosztizált esetek dokumentációjának elemzésével igyekeztünk a különbségek okait feltárni, valamint kerestük ezeknek az eseteknek azon jellemzőit is, amelyek megnehezíthették a helyes diagnózis felállítását.
Módszer:
A 2006-os évben a Mohács Város Kórházának Sürgősségi Betegellátó Részlegén vizsgált betegek adatainak retrospektív vizsgálatát végeztük. A sürgősségi ellátásra vonatkozó főbb adatokat (azonosító, a bekerülés indoka, az ellátó orvos pecsétje, a páciens távozási helye) a sürgősségi részleg naplóiból nyertük. A pszichiátriai sürgősségnek véleményezett esetek további sorsát, azt, hogy a beteg melyik osztályra került felvételre, illetve hogy milyen végleges diagnózis került felállításra, a kórház elektronikus betegnyilvántartó rendszerének, valamint a betegek kórrajzainak áttekintése alapján állapítottuk meg.
Eredmények:
Ötszázkilencvenhat pszichiátriai sürgősségi esetnek véleményezett páciensből 289 (49%) bizonyult a későbbi vizsgálatok alapján pszichiátriai osztályos felvételt igénylő sürgősségnek. Az 596 eset 30%-a osztályos felvételt nem igénylő pszichiátriai sürgősségi megjelenés volt, ezek a páciensek ambuláns ellátásban részesültek. A pszichiátriai sürgősségnek véleményezett esetek közül 125-nél (21%) viszont a további vizsgálatok során nem pszichiátriai sürgősség igazolódott, és végül szomatikus osztályra (75 fő a belgyógyászatra, 20 a neurológiára, 12 az intenzívre, 18 pedig egyéb osztályra) kerültek felvételre.
Következtetés:
Eredményeink alapján megállapíthattuk, hogy a pszichiátriai tüneteket mutató betegek 80%-ánál a sürgősségi részleg diagnosztikus és betegirányító funkciója jól működött. Figyelemre méltó ugyanakkor egyes kórképek, tünetek (atípusos pneumonia, szenzoros afázia) diagnosztikus csapdaként való változatlan ismétlődése. Konklúzióként hangsúlyozzuk az átfogó szemlélet és a sürgősségben megjelenő orvosi „szakmák” közös munkájának szükségességét.
Allocation of Sampling Effort to Optimize Efficiency of Watershed‐Level Ichthyofaunal Inventories
Authors: Smith Katherine L. , Jones Michael L.
Published: September 2008

Sampling protocols for ichthyofaunal inventories have received considerable study at the stream reach level; however, no studies have examined the optimal allocation of sampling effort for watershed‐level inventories. To address this question, we used data from surveys of four Great Lakes watersheds to compare rates of species accumulation among several watershed‐level scenarios of sampling effort allocation (sampling strategies). To allow for quantitative comparisons among strategies, we (1) divided each sampling site into smaller sampling units and separately recorded fish capture data at the smallest unit; (2) stratified the allocation of sampling effort throughout each watershed by stream order; and (3) recorded all sampling and travel costs (i.e., time spent on different tasks). We used a Monte Carlo simulation program to resample the data from each of the four watershed surveys and calculated rates of species accumulation. This technique allowed us to quantitatively compare sampling strategies. Using this program, we determined the optimal values for (1) the length of stream to sample at each reach; (2) the allocation of sampling effort (time) among stream order strata; and (3) the allocation of effort between seasons (spring and summer) for each of the four watersheds. On average, sampling 15, 9, and 9 stream widths per reach in first‐, second‐, and third‐order reaches, respectively, maximized the rates of species accumulation across watersheds. Allocating 50‐70% of the sampling effort to third‐order strata of each watershed yielded the highest rates of species accumulation without increasing the number of species systematically missed in either the lower or upper portions of the watershed. Focusing sampling effort in only one season, either spring or summer, did not consistently increase the rates of species accumulation. Our results provide useful guidance for the design of watershed‐scale ichthyofaunal surveys in Great Lakes basin watersheds. We recommend similar assessments in other regions with contrasting patterns of fish diversity.
Effects of Salinity, Temperature, and Weight on the Survival of Young‐of‐Year Shortnose Sturgeon
Authors: Ziegeweid Jeffrey R. , Jennings Cecil A. , Peterson Douglas L. , Black Marsha C.
Published: September 2008

Anthropogenic modifications of rivers and estuarine habitats have reduced the growth and recruitment of shortnose sturgeon Acipenser brevirostrum throughout its native range. This study used data from laboratory experiments to examine the individual and interactive effects of salinity, temperature, and fish weight on the survival of young‐of‐year shortnose sturgeon. The shortnose sturgeon in these experiments ranged from 56 to 187 mm in total length, from 0.4 to 42.8 g in weight, and from 66 to 144 d posthatch in age. Survival in 23°C water declined as salinity increased, but salinity tolerance increased with body size. The salinity lethal to 50% of the test fish after 48 h ranged from 14.8‰ to 20.9‰. Survival in freshwater declined as temperature increased, but temperature tolerance increased with body size. The temperature lethal to 50% of the test fish after 48 h ranged from 28.2°C to 30.7°C. In factorial experiments, salinity and temperature interacted significantly to affect young‐of‐year survival. The results of the factorial experiments were used to generate a predictive model in which the probability of survival was dependent on salinity, temperature, fish weight, and all interactions among the variables. The results of this study can be used to identify suitable habitats for young‐of‐year shortnose sturgeon. The results of this study also can be used to predict the recruitment bottlenecks that may result from additional anthropogenic disturbances to rivers in the southeastern United States.
Reliability of Bioelectrical Impedance Analysis for Estimating Whole‐Fish Energy Density and Percent Lipids
Authors: Pothoven Steven A. , Ludsin Stuart A. , Höök Tomas O. , Fanslow David L. , Mason Doran M. , Collingsworth Paris D. , Van Tassell Jason J.
Published: September 2008

We evaluated bioelectrical impedance analysis (BIA) as a nonlethal means of predicting energy density and percent lipids for three fish species: Yellow perch Perca flavescens, walleye Sander vitreus, and lake whitefish Coregonus clupeaformis. Although models that combined BIA measures with fish wet mass provided strong predictions of total energy, total lipids, and total dry mass for whole fish, including BIA provided only slightly better predictions than using fish mass alone. Regression models that used BIA measures to directly predict the energy density or percent lipids of whole fish were generally better than those using body mass alone (based on Akaike's information criterion). However, the goodness of fit of models that used BIA measures varied widely across species and at best explained only slightly more than one‐half the variation observed in fish energy density or percent lipids. Models that combined BIA measures with body mass for prediction had the strongest correlations between predicted and observed energy density or percent lipids for a validation group of fish, but there were significant biases in these predictions. For example, the models underestimated energy density and percent lipids for lipid‐rich fish and overestimated energy density and percent lipids for lipid‐poor fish. A comparison of observed versus predicted whole‐fish energy densities and percent lipids demonstrated that models that incorporated BIA measures had lower maximum percent error than models without BIA measures in them, although the errors for the BIA models were still generally high (energy density: 15‐18%; percent lipids: 82‐89%). Considerable work is still required before BIA can provide reliable predictions of whole‐fish energy density and percent lipids, including understanding how temperature, electrode placement, and the variation in lipid distribution within a fish affect BIA measures.
Patterns of Ultraviolet Radiation Exposure in Bluegill Nests over the Course of the Spawning Season
Authors: Olson Mark H. , Adams‐Deutsch Tristan , Cassels Kelly J. , Oliver Amy E. , Mitchell David L.
Published: September 2008

Ultraviolet radiation (UVR; wave length, 280‐400 nm) can be an important source of mortality for fish, particularly during early life history stages. Because UVR exposure varies seasonally owing to solar angle, climatic conditions, and changes in the UV transparency of water, UVR‐induced mortality among temperate fishes may vary as a function of spawning time. We examined patterns of UVR exposure in nests of bluegill Lepomis macrochirus over the course of a spawning season in a highly transparent lake in northeastern Pennsylvania. At the beginning, middle, and end of the spawning season, we measured nest depth and estimated the cumulative UVR exposure of all bluegill nests along three 250‐m transects. Cumulative exposure was then used to predict the UVR‐induced mortality for bluegill larvae in each nest. The median UVR exposure in bluegill nests was highest at the start of the spawning season, and the predicted UVR‐induced larval mortality was at least 10% in 38% of the nests. As the season progressed, the median UVR exposure decreased, and only 4% of the nests were predicted to have larval mortality of at least 10% by the middle and end of the spawning season. This decrease in exposure was partly due to a seasonal decline in UVR transparency. In addition, mean nest depth increased over the course of the spawning season, as bluegills increasingly nested at depths of 4 m or more. Because UVR attenuates with depth, deeper nests received less UVR exposure than did nests closer to the surface. For many species, reproductive success is strongly dependent on spawning time. Our results suggest that in some systems a consequence of early spawning may be an increased risk of UVR‐induced mortality.
Clonal variation in physiological responses of Daphnia magna to the strobilurin fungicide azoxystrobin
Authors: Warming Trine Perlt , Mulderij Gabi , Christoffersen Kirsten Seestern
Published: September 2008

Because of its high grazing potential, Daphnia magna is an ecologically important species in aquatic food webs. This is especially true in small, shallow ponds lacking fish, where grazing by D. magna may have a relatively higher impact on water clarity as compared to larger lakes. Thus, a reduction in daphnid abundance may have dramatic ecological consequences for shallow ponds. At the same time, shallow ponds in close proximity to agricultural areas likely experience higher concentrations of pesticides because of runoff, spray drift, and drain flow. In the present study, the acute and chronic physiological effects of the strobilurin fungicide azoxystrobin on three clones of D. magna originating from different Danish lakes were evaluated. Significant clonal variation in the sensitivity of D. magna toward azoxystrobin was demonstrated. One clone had a 48-h median lethal concentration (LC50) of 0.277 mg/L (95% confidence limits [CL], 0.145 and 0.427 mg/L), which is comparable to the value widely used in risk assessments (0.259 mg/L). The two remaining clones were far more sensitive, however, and had LC50s of 0.071 mg/L (95% CL, 0.034 and 0.126 mg/L) and 0.098 mg/L (95% CL, 0.066 and 0.139 mg/L), respectively. Furthermore, through respiration measurements and life-table experiments, sublethal stress was shown to exist at exposure to an ecologically relevant concentration (0.026 μg/L). Based on these results, we may expect changes in daphnid populations at azoxystrobin concentrations much lower than previously thought. Thus, ponds in the agricultural areas may experience changes in food-web structure even at very low concentrations of azoxystrobin.
Peroxidase-mediated degradation of perfluorooctanoic acid
Authors: Colosi Lisa M. , Pinto Roger A. , Huang Qingguo , Weber Walter J. Jr.
Published: September 2008

Concentrations of aqueous-phase perfluorooctanoic acid (PFOA), a representative perfluorinated aliphatic (PFA) compound, are shown to be reduced effectively via reaction with horseradish peroxidase (HRP), hydrogen peroxide, and a phenolic cosubstrate (4-methoxyphenol). Reaction rate profiles are pseudo–first order, yielding an apparent best-fit removal rate constant of k1 = 0.003/min (r2 = 0.96, n = 14). Approximately 68% depletion of the parent compound and 98% depletion of its related acute aquatic toxicity are achieved in 6 h. Because no PFOA removal is observed in the absence of cosubstrate and/or following consumption thereof, we conclude that radical intermediate species generated during reaction between HRP and 4-methoxyphenol mediate nonspecific depletion of PFOA and that these intermediates may be sufficiently reactive to sever the extremely stable C–F bonds of PFOA. These results are consistent with measurements of reaction by-products, including fluoride ion and various aliphatic species of shortened chain length. Based on these findings, we conclude that PFA degradation may occur via one of two mechanisms: Kolbe decarboxylation followed by stepwise conversion of–CF2 units to CO2 and fluoride ion, or radical abstraction from a double bond with subsequent fragmentation. Our results indicate that under appropriate conditions, enzymatic degradation may comprise a natural transformation pathway for PFAs. Moreover, we anticipate that appropriately engineered enzymatic processes may hold promise for treatment of PFOA-contaminated waters. This, to the best of our knowledge, is the first report to substantiate the efficacy of HRP-catalyzed reactions for contaminant removal via degradative reactions versus polymerization reactions.
State-of-the-Art in Coalbed Methane Drilling Fluids
Authors: Baltoiu Len V. , Warren Brent K. , Natras Thanos A.
Published: September 2008

The production of methane from wet coalbeds is often associated with the production of significant amounts of water. While producing water is necessary to desorb the methane from the coal, the damage from the drilling fluids used is difficult to assess, because the gas production follows weeks to months after the well is drilled. Commonly asked questions include the following:

What are the important parameters for drilling an organic reservoir rock that is both the source and the trap for the methane? Has the drilling fluid affected the gas production? Are the cleats plugged? Does the "filtercake" have an impact on the flow of water and gas? Are stimulation techniques compatible with the drilling fluids used?

This paper describes the development of a unique drilling fluid to drill coalbed methane wells with a special emphasis on horizontal applications. The fluid design incorporates products to match the delicate surface chemistry on the coal, a matting system to provide both borehole stability and minimize fluid losses to the cleats, and a breaker method of removing the matting system once drilling is completed.

This paper also discusses how coal geology impacts drilling planning, drilling practices, the choice of drilling fluid, and completion/stimulation techniques for Upper Cretaceous Mannville-type coals drilled within the Western Canadian Sedimentary Basin. A focus on horizontal coalbed methane (CBM) wells is presented.

Field results from three horizontal wells are discussed, two of which were drilled with the new drilling fluid system. The wells demonstrated exceptional stability in coal for lengths to 1000 m, controlled drilling rates and ease of running slotted liners. Methods for, and results of, placing the breaker in the horizontal wells are covered in depth.
An Alternative to Sand-Control Screens: Is Permeable Cement a Viable Option?
Authors: Vidick Benoit , James Simon , Drochon Bruno
Published: September 2008

The search for a cost-effective alternative to screens has been intensive in the sand-control field. Different systems have been proposed in the past, including various solutions based on permeable cement, but none of them have made a real breakthrough.

This paper presents a new permeable-cement system that has significant advantages over previous systems. In particular, this permeable cement was formed in a one-stage process, eliminating the need for a subsequent treatment to generate permeability. This permeable-cement system also has adequate strength and sufficient permeability for several sand-control applications. However, the durability of the permeable cement was evaluated and found to be poor. Some suggestions are made for possible applications of the permeable cement for both primary and remedial sand-control applications.
Kikeh Batch Setting: Case Study
Authors: Flannery Chris , Choo Benjamin
Published: September 2008

The semisubmersible rig Ocean Rover was used by Murphy Sabah Oil Company to batch-set 23 wellheads in 4,350-ft-deep water with zero health, safety, and environment (HSE) incidents.

The batch-set team worked to maintain safety and performance and to overcome numerous logistical and operational challenges. Implementing lessons learned and development of recommended practices resulted in continuous improvement throughout the project.

The program was completed in 63 days. The average installation time for conductor and surface casing was 3.36 days from start to finish. Total materials used were 50,000 ft of casing, 3,060 tonnes of cement, and 78,000 bbl of 16.6 lbm/gal dynamic kill drilling (DKD) mud.
Improving Formation-Strength Tests and Their Interpretation
Authors: van Oort Eric , Vargo Richard
Published: September 2008

Verifying pressure integrity of a casing string and the adjacent formation is an important requirement during drilling of a well. Crucial decisions on mud weight, kick tolerance, and the setting depth of the next casing string are based on the outcome of formation-strength tests (FSTs) such as leakoff tests (LOTs) or formation-integrity tests (FITs). Moreover, government regulations usually require that a minimum integrity is guaranteed before a well may be deepened.

Yet the majority of FSTs and their interpretations currently carried out in the field can only be characterized as inadequate. Commonly, FSTs lack quality and accuracy because of insensitivity in the hydraulic system to subtle pressure effects in the wellbore, use of highly compressible synthetic or oil muds, nonlinear thermal profiles, poorly understood formation-stress and -strength behavior, or simply because of poor data capturing (e.g., by using hand-generated plots). This may have a significant negative impact on the drilling operation. For instance, when mud-weight windows are assessed incorrectly after testing, lost circulation or well-control problems may ensue on wells with tight drilling margins.

Here, we highlight several of the problems underlying current FSTs and their interpretations, illustrating them with actual field examples [such as the discrepancy often observed between surface readings and downhole pressure-while-drilling (PWD) readings obtained while testing], and show how test artifacts can be either avoided or accounted for. A case is made for the use of downhole recorded pressure data to determine casing-shoe strength correctly.
A New Skin-Factor Model for Perforated Horizontal Wells
Authors: Furui K. , Zhu D. , Hill A. D.
Published: September 2008

Using a combination of analytical calculations and 3D finite-element simulation, we have developed a comprehensive skin-factor model for perforated horizontal wells. In this paper, we present the mathematical model development and validation by comparison with finite-element simulation results. With the new perforation skin model, we then show how to optimize horizontal well perforating to maximize well productivity.

A cased, perforated well may have lower productivity (as characterized by a positive skin factor) relative to the equivalent open-hole completion because of two factors: the convergence of the flow to the perforations, and the blockage of the flow by the wellbore itself. Because of the orientation of a horizontal well relative to the anisotropic permeability field, perforation skin models for vertical wells that consider these effects, notably the Karakas and Tariq model (1991), are not directly applicable to perforated horizontal completions. Using appropriate variable transformations, we derived a skin-factor model for a horizontal perforated completion that is analogous to the Karakas and Tariq (1991) vertical-well model. The empirical parameters in the model were determined from an extensive 3D finite-element simulation study.

The results of the new model show that the azimuth of a perforation (the angle between the perforation tunnel and the maximum permeability direction, usually thought to be in the horizontal direction) affects the performance of perforated completions in anisotropic reservoirs. When perforations are normal to the maximum-permeability direction, perforations will enhance horizontal-well flow compared with an openhole completion (a negative skin factor). But if perforations are in the same direction as the maximum permeability, significant positive skin will result. The new skin-factor model provides a clear guide to the shot density, perforation orientation, and level of perforation damage that is tolerable to create high-productivity perforated completions in horizontal wells.
Geomechanics Aspects of Multiple Fracturing of Horizontal and Vertical Wells
Authors: Soliman M. Y. , East Loyd , Adams David
Published: September 2008

Although unstimulated horizontal wells have1 been successful in naturally fractured reservoirs and in reservoirs with gas- or water-coning problems, fracturing a horizontal well may be a viable option in certain situations. Because of the dependence of fracture orientation on well direction with respect to the stress field, the possibility of fracturing a horizontal well must be considered before the well is drilled. The appropriate contingency plans should be made to anticipate the possible low production from an unstimulated well. It should be remembered that fracturing a horizontal well may also dictate how the wellbore may be completed or oriented. Fracturing a horizontal well may take place in one of the following situations:

Restricted vertical flow caused by low vertical permeability or the presence of shale streaks. Low formation productivity because of low formation permeability. The presence of natural fractures in a direction different from that of induced fractures. Thus, induced fractures have a high chance of intercepting the natural fractures. Low stress contrast between the pay zone and the surrounding layers. In this case, a large fracturing treatment of a vertical well would not be an acceptable option because the fracture would grow in height as well as length. Drilling a horizontal well and creating either several transverse or longitudinal fractures would allow rapid depletion of the reservoir through the fractures.

Although fundamentally similar to fracturing vertical wells, fracturing horizontal wells has its unique aspects that require special attention to secure successful treatment. Differences between horizontal and vertical wells exist in areas of rock mechanics, reservoir engineering, and operational aspects. To start with, the basic rock-mechanics aspects are examined.
Hole Cleaning During Underbalanced Drilling in Horizontal and Inclined Wellbore
Authors: Zhou L.
Published: September 2008

This paper is an extended work of SPE 90038. An aerated non-Newtonian flow and an inclined wellbore section were added to the previous model to study the hole-cleaning problem while drilling an underbalanced well. This new mechanistic model for cuttings transport was developed by combining two-phase hydraulic equations, turbulent boundary layer theory, and particle transport mechanism. It is shown that the model is useful for predicting minimum annular velocity and cuttings bed thickness in horizontal and inclined wellbore geometry. Effects of temperature, bottom hole pressure, liquid flow rate, gas injection rate, cuttings size and density, inclination angle, and rheological properties of drilling mud on hole cleaning are analyzed using this mechanistic model. The model is validated by available experimental data. Computer simulation indicates that cuttings bed thickness is very sensitive to the liquid phase flow rate. It dominates cuttings transport efficiency. However, during underbalanced drilling, increase of liquid phase fraction may not always be feasible while trying to keep a low equivalent circulating density (ECD). Meanwhile, injection of gas has positive effects on cuttings transportation depending on the flow patterns and drilling mud viscosity. Elevated temperature causes a significant increase of bed thickness, and it is important to recognize this negative effect, especially when drilling high-pressure/high-temperature (HPHT) wells. The effect of pressure on cuttings concentration is negative. Larger size and heavier cuttings make hole cleaning more difficult and require higher pump rates for low-viscosity fluids. Increases of liquid phase density result in better hole cleaning. The range of hole angles from approximately 35° to 60° (from vertical) is the most difficult for cuttings transport. Frictional pressure losses in a deviated wellbore highly depend on cutting bed thickness. Simulation results are compared to available experiment data and show good agreement. In summary, this paper presents a model that is useful for practical hole cleaning during underbalanced drilling (UBD).
A New Method of Producing Laterally Stable PDC Drill Bits
Authors: Johnson S.
Published: September 2008

Bit whirl is well documented as a major cause of damage to polycrystalline-diamond-compact (PDC) drill bits and results in short runs, low rate of penetration (ROP), high cost per foot, poor hole quality, and downhole-tool damage. Hence, consistent lateral stability is highly desirable in PDC bits.

This paper presents a new method of producing PDC drill bits that reduce or eliminate bit whirl. Traditionally, attempts to design laterally stable PDC bits have assumed that the forces generated by the bit during stable drilling cause it to begin whirling. The new approach assumes that it is the response of the bit to forced motion off its center that causes whirl.

The new approach has been validated theoretically, in the laboratory, and in the field. Test results from a full-scale drilling rig indicate that this method is superior to existing methods at minimizing bit whirl.

This new method was validated successfully through an extensive field-test program undertaken in the northwest USA, involving high-speed downhole measurements from both conventional 7⅞-in.-diameter PDC drill bits and bits designed using this new method. The results demonstrated that the conventional PDC drill bits exhibited bit whirl throughout the run. The bits designed using the new method eliminated bit whirl completely.

The performance benefits of this new method were demonstrated in a 16-in.-bit section in a Middle Eastern field, where lateral vibrations are a significant problem. Before testing the new-method PDC bit, bit optimization led to the use of high imbalance force designs to minimize lateral vibration. The first test of the new method laterally stable PDC bit set field records for ROP, footage, and cost per foot compared with more than 50 runs with "antiwhirl" (Warren et al. 1990) designs, resulting in savings of more than USD 50,000 per run.

This paper demonstrates how use of the new method can eliminate whirl in both laboratory and field environments and deliver significant performance improvements over existing stability techniques.

This new method represents a significant step forward in the design of PDC bits to mitigate bit whirl, and it has been proved to reduce bit damage, increase run lengths, increase ROP, and deliver sizeable savings for operators.
Efficacy and Safety of the Dipeptidyl Peptidase-4 Inhibitor Alogliptin in Patients With Type 2 Diabetes and Inadequate Glycemic Control
Authors: DeFronzo Ralph A. , Fleck Penny R. , Wilson Craig A. , Mekki Qais ,   on behalf of the Alogliptin Study 010 Group
Published: September 2008

OBJECTIVE—To evaluate the dipeptidyl peptidase-4 (DPP-4) inhibitor alogliptin in drug-naïve patients with inadequately controlled type 2 diabetes.

RESEARCH DESIGN AND METHODS—This double-blind, placebo-controlled, multicenter study included 329 patients with poorly controlled diabetes randomized to once-daily treatment with 12.5 mg alogliptin (n = 133), 25 mg alogliptin (n = 131), or placebo (n = 65) for 26 weeks. Primary efficacy end point was mean change from baseline in A1C at the final visit.

RESULTS—At week 26, mean change in A1C was significantly greater (P < 0.001) for 12.5 mg (−0.56%) and 25 mg (−0.59%) alogliptin than placebo (−0.02%). Reductions in fasting plasma glucose were also greater (P < 0.001) in alogliptin-treated patients than in those receiving placebo. Overall, incidences of adverse events (67.4–70.3%) and hypoglycemia (1.5–3.0%) were similar across treatment groups.

CONCLUSIONS—Alogliptin monotherapy was well tolerated and significantly improved glycemic control in patients with type 2 diabetes, without raising the incidence of hypoglycemia.
Predictors of Suicide in New Generation Jails
Authors: Tartaro Christine , Levy Marissa P.
Published: September 2008

Podular direct supervision jails, also called new generation jails, have been credited by practitioners and some researchers with reducing violence, stress, and suicide among inmates. A recent national comparison of these facilities with more traditional jails revealed that the direct supervision institutions were no less likely than the other jails to experience inmate suicides. The current study involves a closer look at the podular direct supervision facilities. The purpose of this study is to determine which jail characteristics are predictors of suicide. Results indicate that the jail environment and the number of inmate-inmate assaults are predictors of jail suicides. Jails that provide an environment that allows inmates to control lighting, control entrance and exits of cells, and have materials that reduce echoes were less likely to report a suicide in 2003 than those that did not offer those features. Jails with a lower number of inmate-inmate assaults were also less likely to report a suicide in 2003.
Marijuana Treatment and Aggressive Arrest Policies: A Study of New York City
Authors: Sabet Kevin A. , Johnson Bruce D.
Published: September 2008

In the mid to late 1990s, Mayor Rudolph Giuliani and Police Chief William Bratton focused on arresting and detaining people for crimes that contributed to a lower “quality-of-life” in New York City. This aggressive arrest policy resulted in a record growth in marijuana arrests. In 1992, the number of marijuana arrests was around 5,000. By 2000, arrests hit an all time high of about 60,000 (in both years the large majority of these arrests were for misdemeanor arrests). Through a triangulation of data sources, including the Uniform Crime Reports and the Treatment Episode Data Set from 1992 to 2003, and other published accounts, this study shows that entries into treatment for marijuana dramatically increased in New York City at the same time that misdemeanor and felony arrests for marijuana rose. While it is unclear if these arrests caused the treatment increase (vis-à-vis criminal justice referral programs), the presence of these two phenomena shows that policy regimes of increased treatment and increased law enforcement actions can coexist. The oft-heard phrase “treatment versus law enforcement” may represent a false dichotomy in drug policy analysis.
MULTICOMPONENT ITERATIVE METHODS SOLVING STATIONARY PROBLEMS OF MATHEMATICAL PHYSICS
Authors: Abrashina-Zhadaeva Natali G. , Egorov Alexey A.
Published: September 2008

Additive iterative methods of complete approximation for stationary problems of mathematical physics are proposed. The convergence rate in the case of an arbitrary number of commutative and noncommutative partition operators is analysed. The optimal values of the iterative parameter are found and related estimates for the number of iterations are derived. Some applications of suggested iterative methods are discussed.
NUMERICAL ALGORITHMS FOR SIMULATION OF MULTISECTION LASERS BY USING TRAVELING WAVE MODEL
Authors: Čiegis Raimondas , Radziunas Mindaugas , Lichtner Mark
Published: September 2008

Sequential and parallel algorithms for the simulation of the dynamics of high‐power semiconductor lasers is presented. The model equations describing the multisection broad–area semiconductors lasers are solved by the finite difference scheme, which is constructed on staggered grids. This nonlinear scheme is linearized applying the predictor‐corrector method. The algorithm is implemented by using the ParSol tool of parallel linear algebra objects. For parallelization we adopt the domain partitioning method, the domain is split along the longitudinal axis. Results of computational experiments are presented, the obtained speed‐up and efficiency of the parallel algorithm agree well with the theoretical scalability analysis.
POSITIVE SOLUTIONS FOR SYSTEMS OF M‐POINT NONLINEAR BOUNDARY VALUE PROBLEMS
Authors: Henderson Johnny , Ntouyas Sotiris K. , Purnaras Ioannis K.
Published: September 2008

Positive solutions (u(t), v(t)) are sought for the nonlocal (m‐point) nonlinear system of boundary value problems, u” + λa(t)f(v) = 0, v” + λb(t)g(u) = 0, for 0 < t < 1, and satisfying, u(0) = 0, u(1) = . An application of a Guo‐Krasnosel'skii fixed point theorem yields sufficient values of λ for which such positive solutions exist.