bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacogenetics of Epilepsy: One Step Forward?
Authors: Sills Graeme J.
Published: November 2005

Genetic Predictors of the Maximum Doses Patients Receive during Clinical Use of the Antieileptic Drugs Carbamazepine and Phenytoin

Tate SK, Depondt C, Sisodiya SM, Cavalleri GL, Schorge S, Soranzo N, Thom M, Sen A, Shorvon SD, Sander JW, Wood NW, Goldstein DB

Proc Natl Acad Sci USA 2005;102:5507–5512.

Phenytoin and carbamazepine are effective and inexpensive antiepileptic drugs (AEDs). As with many AEDs, a broad range of doses is used, with the final “maintenance” dose normally determined by trial and error. Although many genes could influence response to these medicines, obvious candidates are known. Both drugs target the α-subunit of the sodium channel, encoded by the SCN family of genes. Phenytoin is principally metabolized by CYP2C9, and both are probable substrates of the drug transporter P-glycoprotein. We therefore assessed whether variation in these genes associates with the clinical use of carbamazepine and phenytoin in cohorts of 425 and 281 patients, respectively. We report that a known functional polymorphism in CYP2C9 is highly associated with the maximum dose of phenytoin ( P = 0.0066). We also show that an intronic polymorphism in the SCN1A gene shows significant association with maximum doses in regular use of both carbamazepine and phenytoin ( P = 0.0051, and P = 0.014, respectively). This polymorphism disrupts the consensus sequence of the 5′ splice donor site of a highly conserved alternative exon (5N), and it significantly affects the proportions of the alternative transcripts in individuals with a history of epilepsy. These results provide evidence of a drug-target polymorphism associated with the clinical use of AEDs and set the stage for a prospective evaluation of how pharmacogenetic diagnostics can be used to improve dosing decisions in the use of phenytoin and carbamazepine. Although the case made here is compelling, our results cannot be considered definitive or ready for clinical application until they are confirmed by independent replication.
A Possible Causative Role for Blood–Brain Barrier Failure and Reactive Astrocytosis in Acquired Epilepsy
Authors: D'Ambrosio Raimondo
Published: November 2005

Lasting Blood–Brain Barrier Disruption Induces Epileptic Focus in the Rat Somatosensory Cortex

Seiffert E, Dreier JP, Ivens S, Bechmann I, Tomkins O, Heinemann U, Friedman A

J Neurosci 2004;24:7829–7836

Perturbations in the integrity of the blood–brain barrier have been reported in both humans and animals under numerous pathologic conditions. Although the blood– brain barrier prevents the penetration of many blood constituents into the brain extracellular space, the effect of such perturbations on the brain function and their roles in the pathogenesis of cortical diseases are unknown.

In this study, we established a model for focal disruption of the blood–brain barrier in the rat cortex by direct application of bile salts. Exposure of the cerebral cortex in vivo to bile salts resulted in long-lasting extravasation of serum albumin to the brain extracellular space and was associated with a prominent activation of astrocytes with no inflammatory response or marked cell loss. By using electrophysiological recordings in brain slices, we found that a focus of epileptiform discharges developed within 4 to 7 days after treatment and could be recorded up to 49 days postoperatively in more than 60% of slices from treated animals but only rarely (10%) in sham-operated controls. Epileptiform activity involved both glutamatergic and GABAergic neurotransmission. Epileptiform activity also was induced by direct cortical application of native serum, denatured serum, or albumin-containing solution. In contrast, perfusion with serum-adapted electrolyte solution did not induce abnormal activity, thereby suggesting that the exposure of the serum-devoid brain environment to serum proteins underlies epileptogenesis in the blood–brain barrier–disrupted cortex. Although many neuropathologies entail a compromised blood–brain barrier, this is the first direct evidence that it may have a role in the pathogenesis of focal cortical epilepsy, a common neurologic disease.
Contrast Material‐Induced Renal Failure: An Overview
Authors: SCHRÄDER RAINER
Published: November 2005

The administration of iodinated contrast media (CM) is integral to many cardiovascular procedures. While it is clear that CM provide significant diagnostic benefit, there is some risk of contrast medium‐related adverse events in a small percentage of patients. Potentially the most serious complication associated with the use of iodinated contrast agents is contrast‐induced nephropathy (CIN). Most patients undergoing contrast‐enhanced radiographic procedures are not at risk for CIN, however subjects with pre‐existing renal insufficiency, diabetes mellitus, or cardiovascular disease receiving intra‐arterial administrations of contrast material are at increased risk. Typically, patients with CIN will experience changes in serum creatinine 1–5 days following contrast exposure. While decrements in renal function are generally small and transient, some patients experience a more prolonged decrease and, in rare cases, require dialysis. More importantly, there is substantial literature documenting that patients with CIN after cardiac intervention experience greater morbidity (including prolonged hospitalization) and acute and 1‐year mortality. The present article aims to briefly review the pathogenesis of CIN and reviews current opinion on how best to prevent CIN and manage at‐risk patients.
Microvessels in Chronic Total Occlusions: Pathways for Successful Guidewire Crossing?
Authors: STRAUSS BRADLEY H. , SEGEV AMIT , WRIGHT GRAHAM A. , QIANG BEIPING , MUNCE NIGEL , ANDERSON KEVAN J. T. , LEUNG GENERAL , DICK ALEXANDER J. , VIRMANI RENU , BUTANY JAGDISH
Published: November 2005

Arterial chronic total occlusions (CTO) are a common and clinically relevant problem in patients with coronary artery disease. Percutaneous coronary intervention (PCI) success rates in a wide range of CTO are low, primarily due to inability of guidewire crossing. The pathophysiology of CTO is poorly understood and limits our ability to introduce innovative therapies. Recent studies from our laboratory have suggested that microvessel formation within arterial CTO is a complex process with temporal and regional differences. Moreover, there is evidence from pilot studies that the presence of either microvessels or the particular extracellular matrix environment in the adjacent perivascular tissue can facilitate guidewire crossing and successful PCI. Currently, studies are underway in our experimental CTO model to delineate the pathophysiology of microvessel formation in CTO and its potential role in PCI.
One‐Year Clinical Outcomes After Complete Arterial Coronary Revascularization
Authors: OSTER HARTMUT , SCHWARZ FRANZ , STÖRGER HANS , HOFMANN MANFRED , PIANCATELLI CLAUDIA , THOMAS JULE , HAASE JÜRGEN
Published: November 2005

Background: Conventional coronary bypass surgery applies single internal mammary arteries and saphenous vein graft conduits for revascularization of occluded coronary arteries. While the use of saphenous vein grafts is limited by early graft occlusion, little data exist on clinical experiences with complete arterial revascularization.

Patients and Method: From January 2003 to July 2004, 390 patients were transferred from Red Cross Hospital Cardiology Center to the Rotenburg Cardiovascular Center for coronary bypass operation. From these patients, 200 were selected for complete arterial revascularization. Mean age of the patients was 66.7 ± 8.0 years; 80.5% were male; 68.5% had triple‐vessel disease, 31% had two‐vessel disease, and 0.5% had single‐vessel disease; 32% were diabetic; and 6.5% had a previous bypass operation. Left ventricular ejection fraction was >50% in 85.5% and 30–50% in 14.5%. Double internal mammary artery grafts were used in 98% and single internal mammary artery grafts in 2%. In 51%, the right internal mammary artery was connected with the left internal mammary artery as a T‐graft and in 17%, it was used as a free aortocoronary graft. Radial artery grafts were used in 4%. The average number of anastomoses per patient was 3.4.

Results: During the primary in‐hospital stay, 1.5% of the patients had to undergo reoperation, 3.5% had myocardial infarctions, 3.5% had wound healing complications, 1.0% experienced an ischemic stroke, and 1 patient died following an acute myocardial infarction. At 12 months, 1.0% underwent percutaneous reinterventions, 0.5% had to be reoperated, 0.5% had a myocardial infarction, and 1.0% died. The actuarial survival rate at 12 months was 99%.

Conclusion: When both the internal mammary arteries are used as the preferred surgical strategy, complete arterial revascularization can be performed with excellent clinical results over 12 months.
Cypher Versus Taxus: Are There Differences?
Authors: SILBER SIGMUND
Published: November 2005

Today, drug‐eluting stents (DES) are the standard stenting procedure in the USA and in Switzerland. The objective of this analysis is to answer the two questions: what clinically relevant data regarding DES have been published, and is there a clinically relevant difference between the Cypher and the Taxus stents? Twenty‐two randomized, controlled studies with a total of 11,118 patients were identified: 18 randomized studies compared a DES to a bare metal stent of identical design in 8,301 patients, and 4 randomized studies compared the Cypher and the Taxus stents in 2,817 patients. Three studies regarding Paclitaxel‐releasing stents without polymer (1,235 pats) and five studies regarding Paclitaxel released from a polymer (3,513 pats) were analyzed. Sirolimus released from a polymer was investigated in five studies (2,070 pats). Everolimus released from a polymer was investigated in three studies (166 pats), Biolimus A9 released from a polymer in one (120 pats), and Zotarolimus (ABT‐578) released from a polymer in also one (1,197 pats) trial. Thirteen studies chose either a surrogate primary endpoint (angiographic or IVUS) or a clinical endpoint insufficient for a power calculation. A primary clinical endpoint with an adequate sample size for a power calculation was chosen in three trials for the Taxus stent (TAXUS‐IV, TAXUS‐V, TAXUS‐VI; 2,916 patients), in one trial for the Cypher stent (SIRIUS; 1,058 patients), and in one trial for the Endeavor stent (ENDEAVOR‐II; 1,197 patients). In all these trials, the primary clinical endpoint was reached. Of the four studies comparing Cypher stents to Taxus stents, one did not define the primary endpoint (TAXi), two assumed superiority of the Cypher stent (REALITY with a surrogate endpoint and SIRTAX, a single‐center study), and one was designed as a non‐inferiority trial (ISAR‐Diabetes, single‐center study with a surrogate endpoint). Based on the European Society of Cardiology established strict criteria with a clinical primary endpoint as a prerequisite to recommend a DES, only three DES have thus far had proven positive effects on clinical outcome: the Cypher‐stents, Taxus‐stents, and Endeavor‐stents. A trial proving the superiority of one DES over another would require a multicenter study with a clinical primary endpoint at an adequate power. As long as such a trial does not exist, Cypher and Taxus are regarded as being equivalent.
Percutaneous Saphenous Vein Graft Interventions with and without Distal Filter Wire Protection
Authors: HOFMANN MANFRED , STÖRGER HANS , SCHWARZ FRANZ , SCHWARZ CLAUS‐EBERHARD , REINEMER HARALD , RUEF JOHANNES , SCHÖPF JOSEF , HAASE JÜRGEN
Published: November 2005

Background: Embolic protection during SVG interventions using distal balloon occlusion and aspiration has shown to reduce periprocedural complications compared to unprotected SVG interventions. A similar effect is expected from filter wires.

Patients and Methods: A total of 174 SVG interventions carried out with (group A; n = 87) or without distal filter wire protection (group B; n = 87) were retrospectively matched for the location of distal graft anastomosis and analyzed for baseline and procedural characteristics, for TIMI flow grade before and after PCI, for the postprocedural CK elevation, and for major adverse cardiac events at 30 days and 6 months (primary end point). Location of distal graft anastomosis was the left anterior descending artery in 19.6%, the left diagonal branch in 6.9%, the left marginal branch in 17.2%, the left posterolateral branch in 24.2%, the mid‐segment of the right coronary artery in 28.7%, and the posterior descending artery in 3.4%.

Results: Baseline clinical demographics showed no relevant differences between both the groups. Mean age of vein grafts was 11.7 ± 4.3 years in group A versus 10.6 ± 4.9 years in group B (P = 0.15). The number of stents per lesion was 1.4 ± 0.8 in group A versus 1.0 ± 0.8 in group B (P < 0.01). The total length of stents was 32.2 ± 16.2 mm in group A versus 20.9 ± 12.1 mm in group B (P < 0.01). TIMI flow grade pre was 2.5 ± 0.8 in group A versus 2.7 ± 0.6 in group B (P < 0.05). TIMI flow grade post was 2.9 ± 0.3 versus 2.9 ± 0.2. Improvement of TIMI flow grade after SVG intervention was 0.4 ± 0.7 in group A versus 0.2 ± 0.6 in group B (P < 0.05). Postprocedural CK‐MB elevations were observed in 17 patients of group A versus 14 patients of group B (P = 0.18). At 30 days, there were no myocardial infarctions (MIs) and no deaths in either group. One patient of group A had to be reoperated and four patients of group A underwent repeat PCI (4.6%) versus one patient of group B (1.2%). At 6 months, there were again no MIs and no deaths in either group. Target lesion revascularization rate was 17.3% in group A versus 11.5% in group B (P <0.02).

Conclusion: When distal filter wire protection is used in high risk SVG lesions, the clinical outcome of percutaneous interventions may be equal to low risk SVG lesions without filter wire protection.
Distal Embolic Protection for SVG Interventions: Can We Afford Not to Use It?
Authors: SHAIA NORMAN , HEUSER RICHARD R.
Published: November 2005

The development of atherosclerosis in saphenous vein grafts (SVGs) is one of the limiting factors in coronary artery bypass surgery. Approximately one half of vein conduits are significantly diseased or occluded at 10 years. A surgical revascularization strategy is often not pursued secondary to the incremental risks associated with a repeat bypass procedure. For this reason, percutaneous treatment of SVG disease is often the first option for a majority of patients. However, catheter‐based treatment of SVG disease is associated with increased morbidity and mortality compared with native coronary arterial percutaneous intervention. This is often the result of distal embolization of atherothrombotic disease, leading to the phenomenon of “no‐reflow.” Intraprocedural pharmacological therapy has historically been the mainstay of treatment for these patients. However, more recently, the development of a mechanical embolic protection device has shown to be beneficial for the prevention of these complications. This article will review the types of embolic protection devices and the clinical studies that have proven their necessity in percutaneous SVG intervention.
Percutaneous In Situ Coronary Venous Arterialization: A Catheter‐Based Procedure for Coronary Artery Bypass
Authors: REIFART NICOLAUS
Published: November 2005

Diffuse coronary artery disease is frequently untreatable by coronary artery bypass or angioplasty. Open chest surgical arterialization of the coronary venous system was successfully performed before the widespread use of coronary artery bypass grafting and has been applied in ungraftable patients thereafter. Percutaneous in situ coronary venous arterialization (PICVA™) follows this surgical experience, using a series of unique catheter‐based devices to arterialize isolated segments of coronary vein, forcing retroperfusion of severely ischemic myocardium. In a series of animals, this procedure had been shown to reduce ischemia and myocardial damage in an infarction model. In the PICVA European Safety trial, the first 11 percutaneous applications of catheter‐based coronary bypass in humans revealed feasibility of the technique in highly symptomatic “no‐option” patients. Despite two deaths and six failures to create the bypass, we continue to believe that on further development, the catheter‐based coronary bypass can become a broad‐based interventional application.
Perimembranous and Muscular Ventricular Septal Defects—Morphology Revisited in the Era of Device Closure
Authors: McCARTHY KAREN P. , CHING LEUNG PETER KAI , HO SIEW YEN
Published: November 2005

Transcatheter closure of ventricular septal defects has advanced rapidly with improvements in device designs. We review the morphology of ventricular septal defects in heart specimens for a closer look at the shapes, sizes, and proximity to important structures. The three main types of defects, perimembranous, muscular, doubly committed and juxtaarterial, all have variable morphologies within each group. Oval rather than round shapes are more common. The shapes of muscular defects, in particular, can change from one side of the septum to the other. Perimembranous defects are close to the aortic and tricuspid valves and adjacent to the atrioventricular conduction bundle. Ventricular septal defects are three‐dimensional and require careful assessment of proximity to important structures in their vicinity when assessing suitability for interventional closure.
Function and Mechanism of Action of Dictyostelium Nramp1 (Slc11a1) in Bacterial Infection
Authors: Peracino Barbara , Wagner Carina , Balest Alessandra , Balbo Alessandra , Pergolizzi Barbara , Noegel Angelika A. , Steinert Michael , Bozzaro Salvatore
Published: November 2005

Dictyostelium amoebae are professional phagocytes, which ingest bacteria as the principal source of food. We have cloned the Dictyostelium homologue of human natural resistance‐associated membrane protein 1 (Nramp1) [solute carrier family 11 member 1 (Slc11a1)], an endo‐lysosomal membrane protein that confers on macrophages resistance to infection by a variety of intracellular bacteria and protozoa. The Dictyostelium Nramp1 gene encodes a protein of 53 kDa with 11 putative transmembrane domains. The Nramp1 gene is transcribed during the growth‐phase and downregulated to barely detectable levels upon starvation. To gain insights into their intracellular localization, we fused Nramp1 or the vatB subunit of the V‐H+ATPase with green fluorescent protein and expressed in cells. Green fluorescent protein‐vatB was inserted in membranes of all acidic compartments and the contractile vacuole network and decorated macropinosomes and phagosomes. Green fluorescent protein‐Nramp1 decorated macropinosomes and phagosomes, in addition to intracellular vesicular compartments positive for endosomal SNARE protein Vti1 or vacuolin, a marker of the exocytic pathway. Nramp1 disruption generated mutants that were more permissive hosts than wild‐type cells for intracellular growth of Legionella pneumophila and Micobacterium avium. Nramp1 overexpression protected cells from L. pneumophila infection. Evidence is provided that Nramp1 transports metal cations out of the phagolysosome in an ATP‐dependent process and that L. pneumophila and M. avium use different mechanisms to neutralize Nramp1 activity.
Structure and mechanism of the ThDP‐dependent benzaldehyde lyase from Pseudomonas fluorescens
Authors: Mosbacher Tanja G. , Mueller Michael , Schulz Georg E.
Published: November 2005

Pseudomonas fluorescens is able to grow on R‐benzoin as the sole carbon and energy source because it harbours the enzyme benzaldehyde lyase that cleaves the acyloin linkage using thiamine diphosphate (ThDP) as a cofactor. In the reverse reaction, this lyase catalyses the carboligation of two aldehydes with high substrate and stereospecificity. The enzyme structure was determined by X‐ray diffraction at 2.6 Å resolution. A structure‐based comparison with other proteins showed that benzaldehyde lyase belongs to a group of closely related ThDP‐dependent enzymes. The ThDP cofactors of these enzymes are fixed at their two ends in separate domains, suspending a comparatively mobile thiazolium ring between them. While the residues binding the two ends of ThDP are well conserved, the lining of the active centre pocket around the thiazolium moiety varies greatly within the group. Accounting for the known reaction chemistry, the natural substrate R‐benzoin was modelled unambiguously into the active centre of the reported benzaldehyde lyase. Due to its substrate spectrum and stereospecificity, the enzyme extends the synthetic potential for carboligations appreciably.
The hyperfluidization of mammalian cell membranes acts as a signal to initiate the heat shock protein response
Authors: Balogh Gábor , Horváth Ibolya , Nagy Enikõ , Hoyk Zsófia , Benkõ Sándor , Bensaude Olivier , Vígh László
Published: November 2005

The concentrations of two structurally distinct membrane fluidizers, the local anesthetic benzyl alcohol (BA) and heptanol (HE), were used at concentrations so that their addition to K562 cells caused identical increases in the level of plasma membrane fluidity as tested by 1,6‐diphenyl‐1,3,5‐hexatriene (DPH) anisotropy. The level of membrane fluidization induced by the chemical agents on isolated membranes at such concentrations corresponded to the membrane fluidity increase seen during a thermal shift up to 42 °C. The formation of isofluid membrane states in response to the administration of BA or HE resulted in almost identical downshifts in the temperature thresholds of the heat shock response, accompanied by increases in the expression of genes for stress proteins such as heat shock protein (HSP)‐70 at the physiological temperature. Similarly to thermal stress, the exposure of the cells to these membrane fluidizers elicited nearly identical increases of cytosolic Ca2+ concentration in both Ca2+‐containing and Ca2+‐free media and also closely similar extents of increase in mitochondrial hyperpolarization. We obtained no evidence that the activation of heat shock protein expression by membrane fluidizers is induced by a protein‐unfolding signal. We suggest, that the increase of fluidity in specific membrane domains, together with subsequent alterations in key cellular events are converted into signal(s) leading to activation of heat shock genes.
Evaluation of detergents for the soluble expression of α‐helical and β‐barrel‐type integral membrane proteins by a preparative scale individual cell‐free expression system
Authors: Klammt Christian , Schwarz Daniel , Fendler Klaus , Haase Winfried , Dötsch Volker , Bernhard Frank
Published: November 2005

Cell‐free expression has become a highly promising tool for the fast and efficient production of integral membrane proteins. The proteins can be produced as precipitates that solubilize in mild detergents usually without any prior denaturation sttif. Alternatively, membrane proteins can be synthesized in a soluble form by adding detergents to the cell‐free system. However, the effects of a representative variety of detergents on the production, solubility and activity of a wider range of membrane proteins upon cell‐free expression are currently unknown. We therefore analyzed the cell‐free expression of three structurally very different membrane proteins, namely the bacterial α‐helical multidrug transporter, EmrE, the β‐barrel nucleoside transporter, Tsx, and the porcine vasopressin receptor of the eukaryotic superfamily of G‐protein coupled receptors. All three membrane proteins could be produced in amounts of several mg per one ml of reaction mixture. In general, the detergent 1‐myristoyl‐2‐hydroxy‐sn‐glycero‐3‐[phospho‐rac‐(1‐glycerol)] was found to be most effective for the resolubilization of membrane protein precipitates, while long chain polyoxyethylene‐alkyl‐ethers proved to be most suitable for the soluble expression of all three types of membrane proteins. The yield of soluble expressed membrane protein remained relatively stable above a certain threshold concentration of the detergents. We report, for the first time, the high‐level cell‐free expression of a β‐barrel type membrane protein in a functional form. Structural and functional variations of the analyzed membrane proteins are evident that correspond with the mode of expression and that depend on the supplied detergent.
The influence of heterodimer partner ultraspiracle/retinoid X receptor on the function of ecdysone receptor
Authors: Palli Subba R. , Kapitskaya Mariana Z. , Potter David W.
Published: November 2005

A pair of nuclear receptors, ecdysone receptor (EcR) and ultraspiracle (USP), heterodimerize and transduce ecdysteroid signals. The EcR and its nonsteroidal ligands are being developed for regulation of transgene expression in humans, animals and plants. In mammalian cells, EcR:USP heterodimers can function in the absence of ligand, but EcR/retinoid X receptor (EcR:RXR) heterodimers require the presence of ligand for activation. The heterodimer partner of EcR can influence ligand sensitivity of EcR so that the EcR/Locusta migratoria RXR (EcR:LmRXR) heterodimers are activated at lower concentrations of ligand when compared with the concentrations of ligand required for the activation of EcR/Homo sapiens RXR (EcR:HsRXR) heterodimers. Analysis of chimeric RXRs containing regions of LmRXR and HsRXR and point mutants of HsRXR showed that the amino acid residues present in helix 9 and in the two loops on either end of helix 9 are responsible for improved activity of LmRXR. The EcR:Lm‐HsRXR chimera heterodimer induced reporter genes with nanomolar concentration of ligand compared with the micromolar concentration of ligand required for activating the EcR:HsRXR heterodimer. The EcR:Lm‐HsRXR chimera heterodimer, but not the EcR:HsRXR heterodimer, supported ligand‐dependent induction of reporter gene in a C57BL/6 mouse model.
Purification, cDNA cloning, and expression profiles of the cyclobutane pyrimidine dimer photolyase of Xenopus laevis
Authors: Tanida Hiroaki , Tahara Eiji , Mochizuki Miwa , Yamane Yukiko , Ryoji Masaru
Published: November 2005

Photolyase is a light‐dependent enzyme that repairs pyrimidine dimers in DNA. Two types of photolyases have been found in frog Xenopus laevis, one for repairing cyclobutane pyrimidine dimers (CPD photolyase) and the other for pyrimidine–pyrimidone (6–4)photoproduct [(6–4)photolyase]. However, little is known about the former type of the Xenopus photolyases. To characterize this enzyme and its expression profiles, we isolated the entire coding region of a putative CPD photolyase cDNA by extending an EST (expressed sequence tag) sequence obtained from the Xenopus database. Nucleotide sequence analysis of the cDNA revealed a protein of 557 amino acids with close similarity to CPD photolyase of rat kangaroo. The identity of this cDNA was further established by the molecular mass (65 kDa) and the partial amino acid sequences of the major CPD photolyase that we purified from Xenopus ovaries. The gene of this enzyme is expressed in various tissues of Xenopus. Even internal organs like heart express relatively high levels of mRNA. A much smaller amount was found in skin, although UV damage is thought to occur most frequently in this tissue. Such expression profiles suggest that CPD photolyase may have roles in addition to the photorepair function.
Contrary food requirements of the larvae of twoCurtonotus(Coleoptera: Carabidae:Amara) species
Authors: Saska P.
Published: November 2005

The larvae of carabids that are granivorous as adults can be granivorous, omnivorous or carnivorous. The differences in larval food preferences ofAmara aulicaandAmara convexiuscula, two closely related species of the subgenusCurtonotus, were studied. Survival and duration of development of non‐diapausing first and second instar larvae were compared. The third instar larvae were not studied because they go into diapause prior to pupation. The larvae were fed diets consisting of insect larvae (Tenebrio molitor), seeds ofArtemisia vulgaris, Tripleurospermum inodorum, Urtica dioicaorCirsium arvenseand a mixed diet consisting of insect larvae and seed. Larvae ofA. aulicarequired seeds for successful development, whereas those ofA. convexiusculadeveloped on both an insect diet and seeds ofArtemisia. The difference in larval food requirements facilitates the coexistence of these closely related species, which frequently share the same habitat.
Effects of Nitrogen fertilisation and regrowth period on fatty acid concentrations in perennial ryegrass (Lolium perenne L.)
Authors: Elgersma A. , Maudet P. , Witkowska I.M. , Wever A.C.
Published: November 2005

Information on lipids in forages is scarce, and effects of nitrogen (N) application level and regrowth period on the fatty acid (FA) concentration and composition of perennial ryegrass (Lolium perenne L.) were studied. N was applied at 0, 45 and 100 kg ha−1, and swards were cut after various regrowth periods, resulting in six treatments designed as randomised blocks with three replicates. The stages of development ranged from vegetative to elongating swards, with herbage yield levels from 1.9 to 4.2 t dry matter (DM) ha−1. Concentrations of individual FA were determined by gas chromatography, and canopy characteristics and herbage quality were assessed. The treatments resulted in canopies with contrasting DM yields and protein concentrations. Five FAs, representing 98% of total FAs, were studied in detail. On an average, the concentration of these major FAs in fresh grass was 15.1 g kg−1 DM, and 69% of the major FAs consisted of C18:3. Regrowth period affected (P < 0.05) the total FA concentration, and significantly (P < 0.01) lower concentrations of C18:3 and C16:1 were found after a longer period of regrowth. N application resulted in higher (P < 0.001) concentrations of all FAs. The FA composition was not affected by N application, but a longer regrowth period significantly (P < 0.001) decreased the proportion of C18:3 and increased those of C18:2 and C16:0. A strong, positive overall linear relation was found between the concentrations of total FAs and C18:3 with the crude protein concentration in the herbage. These studies demonstrate opportunities to affect the FA concentration and composition of FA in herbage through management strategies, which could affect milk FA composition.
Simulations to Verify Horizontal Flow Measurements from a Borehole Flowmeter
Authors: James Scott C , Jepsen Richard A. , Beauheim Richard L. , Pedler William H. , Mandell Wayne A.
Published: November 2005

This paper reports on experiments and simulations of subsurface flow from a slotted acrylic tube deployed in a sand‐tank flow chamber for two different purposes. In the first instance, the slotted tube is used to represent a single fracture intersected by an uncased well. In the second instance, the slotted tube is used to represent a multislot well screen within a porous medium. In both cases, the scanning colloidal borescope flowmeter (SCBFM) measures ground water velocity within the well by imaging colloids traveling through a well to measure their speed and direction. Measurements are compared against model simulations. For the case of a slotted tube representing a single fracture, SCBFM and model results agree with respect to the flow direction and to within a factor of 1.5 for the speed near the well’s center. Model and experimental agreement lend confidence that for an uncased well drilled in a fractured‐rock medium, a calibrated SCBFM could be used to identify and quantify flowing features. Next, the SCBFM was deployed in a four‐column multislotted casing with slots aligned with the flow direction. Another numerical model was developed to estimate the flow field within this well screen to evaluate the potential usefulness of employing the SCBFM in a screened well to estimate flow speed and direction in the surrounding porous medium. Results indicate that if the slots are not aligned with the flow, the SCBFM may only provide order‐of‐magnitude speed measurements and direction measurements with an uncertainty of approximately ±25°.
Maximum Wave Height Distribution in a Sea State: Effects of Record Length and Spectral Peakedness
Authors: Rodríguez Germán , Pacheco Mercedes , Soares C. Guedes
Published: November 2005

The probability distribution of the maximum wave height in a sea state is examined in terms of the spectral peakedness and the sea state duration. The study is based on the analysis of numerically simulated Gaussian wave records with given target spectra to fulfill the long duration and stationarity jointly required conditions, seldom found in nature. Results indicate a clear dependence of the probability distribution structure and location on the record length and the spectral shape.
Nonlinear Model for Sub- and Superharmonic Motions of a MDOF Moored Structure, Part 2—Sensitivity Analysis and Comparison
Authors: Yim S. C. S. , Raman S. , Palo P. A.
Published: November 2005

The nonlinear R-MI/SO system identification procedure and the parameters of the MDOF system identified in Part 1 are examined in detail in this paper. A parametric study is conducted and the results are presented on the sensitivity of the system parameters for two key nonlinear responses—subharmonic and superharmonic resonances. The parameters are compared to determine the appropriateness of using a single set of system parameters for both response regions. A detailed comparison of the MDOF and the corresponding SDOF system results is performed. The knowledge gained from the SDOF and MDOF studies on the applicability of the R-MISO technique for the system identification of MDOF submerged moored structures is discussed. The results show that the MDOF extension of the R-MI/SO nonlinear system identification technique works well; the resulting system parameters are relatively constant and can be applied to the both the sub- and superharmonic regions.
Nonlinear Model for Sub- and Superharmonic Motions of a MDOF Moored Structure, Part 1—System Identification
Authors: Raman S. , Yim S. C. S. , Palo P. A.
Published: November 2005

In this first part of a two-part study, the general nonlinear system identification methodology developed earlier by the authors for a single-degree-of-freedom (SDOF) system using the reverse-multi-input/single-output (R-MI/SO) technique is extended to a multi-degree-of-freedom (MDOF), sub-merged, moored structure with surge and heave motions. The physical nonlinear MDOF system model and the formulation of the R-MI/SO system-identification technique are presented. The corresponding numerical algorithm is then developed and applied to the experimental data of the MDOF system using only the subharmonic motion responses to identify the system parameters. The resulting model is then employed in Part 2 for a detailed analysis of both the sub and superharmonic dynamic behavior of the MDOF experimental system and a comparison of the MDOF response results and observations with those of the corresponding SDOF system examined earlier by the authors.
On the Profile of Large Ocean Waves
Authors: Guedes Soares C. , Pascoal R.
Published: November 2005

Wave data obtained from simulations from an offshore basin and from field measurements were used to provide an assessment of the adequacy of describing the most likely time trace profile around large ocean wave crests based on the information provided by the autocorrelation function. It was concluded that the model is adequate in linear cases, but in high sea states, where nonlinear behavior is apparent, it starts becoming less appropriate.
Effects of Alcohol on the Vibrational Relaxation in Liquid CS2
Authors: Slie W. M. , Litovitz T. A.
Published: November 2005

Ultrasonic attenuation measurements were made in liquid carbon disulfide over a frequency range from 5 to 155 Mc at a temperature of −63°C. Further measurements were made when methyl, propyl, and butyl alcohol were added in concentrations up to 0.06 mole percent. In each case the relaxation frequency is increased linearly with the amount of alcohol added. The relaxation frequency for pure CS2 is 27.8 Mc. The shifts of relaxation frequency in liquid CS2 with alcohol added are:

methyl alcohol 24.7 Mc/mole percent

propyl alcohol 38.7 Mc/mole percent

butyl alcohol 50.7 Mc/mole percent.

The collision probabilities (P) of like and unlike molecules in the liquid as compared to the gas are unexpectedly close, (PAB/PAA)liq being approximately 0.65 (PAB/PAA)gas. Possible reasons for this will be considered.
Solution of Some Common Problems of Electroacoustics with the Aid of a Digital Computer
Authors: Brinkerhoff D. E.
Published: November 2005

Digital computers have proven themselves to be a useful tool in the solution of many scientific and engineering problems. To date, however, its use in the solution of electroacoustic problems has been very limited. A mathematical treatment of the equivalent electroacoustic networks often produces large systems of complex simultaneous equations which are time-consuming to solve by hand-calculations. As a result, the average electroacoustical engineer has developed a “feel” for the analog approach in preference to the classical methods. The ready facility of digital computers to perform innumerable arithmetic operations at high speed and without mistakes makes it now feasible to revive classical methods as a useful engineering tool. In this paper we will discuss the use of a computer to (1) calculate the gain-frequency characteristic of a transistorized audio amplifier, (2) to predict the low-frequency response and sensitivity of proposed loudspeaker designs. and (3) as an aid to predict the acoustic load characteristic of proposed loudspeaker locations.
Frequency Shift for Loud Tones of the Clarinet
Authors: Backus John
Published: November 2005

The theory outlined in the previous paper [J. Acoust. Sec. Am. 34, 1991 (1962)] develops an expression for the shift in playing frequency of the clarinet as a function of reed phase shifts, reed opening, and clarinet Q, when the instrument is played softly. This theory has now been extended to cover the frequency shift for loud tones. Use is made of the experimental observation that for loud tones the reed is in contact with the mouthpiece for very nearly one half-cycle, and that the maximum displacement of the reed from the mouthpiece during the other half-cycle is always less than the displacement with blowing pressure removed. The fundamental component of the air flow through the pulsating reed opening is obtained and evaluated to give a standing wave inside the clarinet, which in turn produces the assumed reed motion. The result is an expression for frequency shift for loud tones, which resembles closely the previously obtained expression for soft tones. [This work was supported by a grant from the National Science Fonndation.]
Mathematical Model for the Perception of Redundancy and Stability in Musical Scales
Authors: Rothenberg David
Published: November 2005

Composers of synthetic music, although no longer bound by the constraints of fixed-tuned instruments, must still reckon with the reference structures that listeners impose on musical tones. Indeed, acoustically identical intervals will be perceived differently when these structures are altered by variations either in interval size or in timbre. Existing musical scales appear to be characterized by minimum redundancy, in the sense that few tones can be predicted from a knowledge of those already present, and by maximum stability, in the sense that acoustically equivalent intervals tend to possess equal numbers of interpolated tones. A mathematical model is proposed to measure the redundancy and stability of any scale, and a computer program has been written to implement it. The input consists of a set of integers describing the acoustic distances between consecutive tones within an octave from which the program creates a combinatorial matrix. Redundancy is calculated from the occurrence of unique combinations and stability from a count of the different contexts in which each interval occurs. When applied to existing scales, the model accounts for many of the historical rules of composition. It also permits one to evaluate new scales and predict their perceptual properties.
Experimental Investigation of Acoustic Resonance in Solid-Propellant Combustion
Authors: Ryan Norman V.
Published: November 2005

Oscillatory burning is a complicated phenomenon. The most fruitful and stimulating contribution to its understanding has been the acoustic theory of F. T. McClure, R. W. Hart, and their associates. The most important single concept of the theory is the recognition of the acoustic admittance as the key property of the combustion process. Of the several streams of research aimed at determining the acoustic admittance of burning surfaces, the most productive has been that employing the device known as the side-vented endburner. Work with this tool is proceeding in at least seven laboratories, the three that have been in the business longest being at the University of Utah (UU), at the Naval Ordnance Test Station (NOTS), and at the Ballistics Research Laboratory (BRL). This paper summarizes related aspects of the work at these three laboratories. Despite variations in burner design, experimental procedures, kinds of data, and data-processing methods, the three laboratories report acoustic admittances in good agreement. In addition to their common work, the three laboratories have branched into other aspects of the oscillatory-burning problem. Some of these aspects are investigation of burner characteristics (BRL), the quantitative influence of oscillatory-burning suppressants (NOTS), and the participation of the solid phase in acoustic oscillations (UU).
Utilization of Combustion-Driven Oscillations
Authors: Putnam Abbott A.
Published: November 2005

The possible applications of combustion-driven oscillations fall into two categories. The first category includes applications that are related to the combustion process itself, such as those concerned with the possibility of alterlog space heat-release rate, combustion efficiency, heat transfer to surfaces, and agglomeration of solid or liquid products of combustion. A consideration of available experimental and theoretical information indicates that none of these applications are too promising when compared with alternative methods of performing the same functions. The second category includes applications that use pulsatory phenomena to do a particular iob. Examples are the application of valveless pulse jets to (a) the propulsion of drones, (b) helicopter blade-tip propulsion, (c) cutting of Arctic ice, and (d) inducing pressure rises in through-flow combustion systems. For one reason or another, most of these ideas have been dropped. However, the use of the pulsating-combustion process to supply both the air at a high flow velocity to a combustor and the products of combustion at a high velocity to a heat exchanger, thereby making possible a compact self-contained unit, appears to have great promise. One such unit of residential boiler size is already available. Although this unit is valved as was the V-1, conversion to a valveless unit appears possible. The development of industrial-sized units appears equally feasible. Apparently the development of such units is contingent upon (a) adequate understanding of how to design effective aerodynamic valves, and (b) the collaboration of an inventor, experimentalist, analyst, and financier on a specific program.
Acoustic and Photographic Studies of Solid Rocket-Propellant Combustion Instability
Authors: Watermeier Leland A. , Strittmater Richard C.
Published: November 2005

Solid-propellant combustion-instability studies at the Ballistic Research Laboratories have been concerned with three main areas: namely, (1) a photographic investigation of aluminum-additive burning phenomena, (2) acoustic admittance measurements of the burning surface, and (3) measurement of acoustic erosivity effects on the burning rate. The first program, which was recently completed, was a photographic study of possible aluminum-additive contributions to low-frequency instability. In this investigation, propellant slabs were burned in a windowed and vented chamber. A rotating slotted wheel was pulled over the vent in some instances to provide pressure waves normal to the burning surface. A short film is shown of some of the test runs. The second program is concerned with the measurement of the acoustic admittance of a burning-propellant surface, using a resonant-tube technique. This work closely parallels that at the Naval Ordnance Test Station and the University of Utah. Recent studies have been aimed at evaluating experimentally some of the sources of acoustic losses in this system. The third program is a study of the dependence of the burning rate of a propellant on the frequency and magnitude of the fluctuating gas velocity parallel to the transpiring surface. A description of the apparatus and a summary of recent results are given.
Acoustic Energy Losses in Rocket-Engine Cavities
Authors: Cantrell R. H. , Hart R. W. , McClure F. T.
Published: November 2005

The presence of a mean-flow field, steady-state temperature gradients, and an exhaust port give the rocket-engine cavity somewhat different acoustic properties from the cavities usually encountered by acousticians. As a result, the gain-loss balance of acoustic energy in the cavity can be significantly changed from the usual case. For example, the cavity walls are often much cooler than the main body of gas, so that the wall losses must not be calculated in the usual way. We discuss some of the factors that affect the theoretical calculation of acoustic losses. [Work supported by Bureau of Naval Weapons, U. S. Department of the Navy, under NOw 62-0604-c.]
Reflection and Refraction of Magnetoacoustic Waves at an Interface
Authors: Pridmore-Brown David
Published: November 2005

The reflection and refraction of plane magnetohydrodynamic waves at an interface separating two different media are studied for various orientations of the external magnetic field. It is pointed out that, by making use of trace velocity plots, it is a simple matter to determine the nature and disposition of the reflected and refracted waves that are generated by an incident wave of any given species.
Microphone-Reciprocity Calibration
Authors: Bonk Basil A.
Published: November 2005

A simplified technique of performing a closed-coupler (cylindrical cavity) reciprocity calibration of microphones is discussed All three transducers needed in the calibration procedure remain as parts of the coupler throughout the measurement. A multiple-function switch is used to connect the circuits for the required operations in sequence, without physically interchanging transducers. The same switch operates an analog computer, which uses a logarithmic potentiometer to solve the necessary calculations. The auxiliary transducer is a piezoelectric ceramic ring, which makes up the cylindrical wall of the cavity; thus, difficulties associated with having all three transducers in the coupler at the same time are avoided. Considerations involved in using this piezoelectric ring are discussed. Additional features of the calibration technique are (1) use of a capacitor in the measurement of the driving current of the reciprocal transducer, and (2) use of a resistive-attenuator-insert technique in the measurement of open-circuit voltage ratios. The calibrator is designed for calibration of a front-damped piezoelectric-ceramic microphone, and the problems resulting from the front-damping are discussed.