bluuebunny/crossref_metadata_2025 huggingface dataset:
A linearized Euler finite-difference time-domain sound propagation model with terrain-following coordinates
Authors: Heimann Dietrich , Karle Regina
Published: June 2006

The equations of a linearized Euler finite-difference time-domain model for sound propagation through an inhomogeneous and moving atmosphere above absorbing ground are adapted to terrain-following coordinates. With the transformed numerical grid the effect of gentle orography is fully considered and the shortcomings of the representation of the orography by blocked-out grid cells in an untransformed grid are avoided. Comparisons with an analytical method to predict the interference patterns of a monochromic sound field above an idealized hill with rigid ground show good agreement. Further applications include absorbing ground and wind. A three-dimensional application also is discussed.
Effect of masker-frequency variability on the detection performance of infants and adults
Authors: Leibold Lori J. , Werner Lynne A.
Published: June 2006

The effect of masker-frequency variability on the detection performance of 7–9 month-old infants and adults was examined. Listeners detected a 300-ms 1000-Hz pure tone masked by: (1) A random-frequency two-tone complex; (2) a fixed-frequency two-tone complex; or (3) a broadband noise. Maskers repeated at 300-ms intervals throughout testing at 60dB SPL. The signal was presented simultaneously with one presentation of the masker. Thresholds were determined adaptively using an observer-based method. Infants’ thresholds were higher than adults’ in all conditions, but infants’ and adults’ thresholds changed with masker condition in qualitatively similar ways. The fixed two-tone complex produced masking for both age groups, but more masking for infants than for adults. For infants and adults, the random two-tone complex produced more masking than broadband noise, but the difference was greater for infants than for adults. For infants and adults, the random two-tone complex produced more masking than the fixed two-tone complex, and the difference between these conditions was similar for both age groups. These results suggest that infants are more susceptible to informational masking than adults in the absence of spectral variability. Whether infants are more susceptible to the effects of masker-frequency variability than adults remains to be clarified.
Acousto-mechanical and thermal properties of clotted blood
Authors: Nahirnyak Volodymyr M. , Yoon Suk Wang , Holland Christy K.
Published: June 2006

The efficacy of ultrasound-assisted thrombolysis as an adjunct treatment of ischemic stroke is being widely investigated. To determine the role of ultrasound hyperthermia in the process of blood clot disruption, the acousto-mechanical and thermal properties of clotted blood were measured in vitro, namely, density, speed of sound, frequency-dependent attenuation, specific heat, and thermal conductivity. The amplitude coefficient of attenuation of the clots was determined for 120kHz, 1.0MHz, and 3.5MHz ultrasound at room temperature (20±2°C). The attenuation coefficient ranged from 0.10to0.30Np∕cm in porcine clots and from 0.09to0.23Np∕cm in human clots. The experimentally determined values of specific heat and thermal conductivity for porcine clotted blood are (3.2±0.5)×103J∕kg∙K and 0.55±0.13W∕m∙K, respectively, and for human clotted blood are (3.5±0.8)×103J∕kg∙K and 0.59±0.11W∕m∙K, respectively. Measurements of the acousto-mechanical and thermal properties of clotted blood can be helpful in theoretical modeling of ultrasound hyperthermia in ultrasound-assisted thrombolysis and other high-intensity focused ultrasound applications.
Chronic exercise and skeletal muscle power in older men
Authors: Dreyer Hans C , Schroeder E Todd , Hawkins Steven A , Marcell Taylor J , Tarpenning Kyle M , Vallejo Alberto F , Jensky Nicole E , Shaibi Gabriel Q , Spears Stefany , Yamada Ryan , Wiswell Robert A
Published: June 2006

We sought to determine the effects of age and chronic exercise on muscle power in older males. We examined 32 older males 60-74 years of age and grouped as sedentary (CON, n = 11), chronic endurance trained (ET, n = 10), and chronic endurance trained + resistance training (ET + RT, n = 11). Exercise history was obtained by questionnaire. Absolute strength and power measures were obtained by the one-repetition maximum method. Relative strength and power were determined by dividing the absolute measure by the muscle mass involved in the exercise. Total and regional muscle mass was measured by DXA. Absolute and relative leg power were not significantly different among the 3 groups. In contrast, absolute leg press strength was greater in ET + RT compared with CON, and relative leg press strength was greater in ET and ET + RT compared with CON. Chronic running combined with resistance training may therefore enhance absolute and relative muscle strength in older adults, but does not influence muscle power. Endurance exercise may inhibit the ability of resistance exercise to positively influence skeletal muscle power.Key words: aging, strength, running, resistance training.
Effect of resistance and aerobic training on regional body composition in previously recreationally trained middle-aged women
Authors: Fleck Steven J , Mattie Cora , Martensen III Henry C
Published: June 2006

Twelve middle-aged women (mean age 41.9 ± 1.6 y) performed variable-cam resistance training and aerobic training 3 times/week for 14 weeks. One repetition maximum (1 RM) significantly increased between pre-training and training week 7 (13.1%-17.8%), between training week 7 and post-training (10.8%-14.1%), and between pre-training and post-training (25.5%-30.9%). Total-body lean soft tissue and total % body fat determined by duel-energy X-ray absorptiometry (DEXA) significantly increased (2.2%) and decreased (1.4%), respectively. Arm, trunk, and total upper-body (arm + trunk) lean soft tissue significantly increased (0.7%-4.6%). Total body fat tissue and all regional measures of fat tissue and % fat showed no significant changes. Significant correlations were shown between pre-testing and post-testing 1 RM in the bench press, lat pull down, and overhead press in all instances, except for post-training bench press and total upper-body lean soft tissue (r = 0.58-0.90). In contrast, non-significant correlations were shown between pre- and post-testing 1 RM of the leg press, with the exception of pre-training and total lean soft tissue and pre-training and leg lean soft tissue. In conclusion, resistance training resulted in consistent strength gains in middle-aged women, which were accompanied by regional changes in upper-body composition, whereas lower-body composition moved in the hypothesized direction, but did not achieve significance.Key words: body composition, dual-energy X-ray absorptiometry, strength training, variable cam.
Are the relationships between early activation of lymphocytes and cortisol or testosterone influenced by intensified cycling training in men?
Authors: Smith Carine , Myburgh Kathryn H
Published: June 2006

The effects of exercise training on lymphocyte responses, as well as changes in circulating endocrine parameters at rest, were investigated. Seven male cyclists participated in a 4 week high-intensity (HI) cycling training intervention. Training improved performance significantly (peak power output (PPO): 1.4%, p < 0.05; 5 km time trial: 3.8%, p < 0.01; 40 km time trial: 0.4%, p < 0.05). Resting hormone concentrations (testosterone, sex hormone binding globulin (SHBG), cortisol, corticosteroid-binding globulin (CBG), and dehydroepiandrosterone-sulphate (DHEA-S)) were unchanged, with the exception of a 20% decrease in testosterone post-HI training (p < 0.067). Subjects' CD3+cell counts decreased by 15% (p < 0.05), owing to significantly decreased CD4+cell counts and slightly lower CD8+and natural killer (NK) cell counts. Spontaneous in vitro CD69 expression increased in CD4+cells (mean ± SD, pre: 12 ± 6 cells·µL-1; post: 35 ± 37 cells·µL-1; p < 0.05), but not in CD8+cells (pre: 20 ± 29 cells·µL-1; post: 33 ± 16 cells·µL-1). Mitogen-induced CD69 expression decreased in both CD4+(pre: 1570 ± 1258 cells·µL-1; post: 596 ± 597 cells·µL-1; p < 0.05) and CD8+lymphocytes (pre: 676 ± 434 cells·µL-1; post: 412 ± 235 cells·µL-1; p < 0.05). Testosterone correlated positively with several immune parameters at baseline, whereas cortisol correlated negatively with parameters of the innate immune system post-HI training. We conclude that the stress of unaccustomed exercise is evident in resting lymphocytes, but not in resting endocrine parameters. However, correlations between testosterone and cortisol and immune parameters suggest that these 2 hormones play a role in modulating immune status. Our results indicate the importance of assessing both spontaneous and mitogen-induced aspects of immune-cell activation.Key words: CD69, DHEA, lymphocytes, exercise.
Exercise intensity during repeated days of racing in professional triathletes
Authors: Hue Olivier , Galy Olivier , Gallais Daniel Le
Published: June 2006

The purpose of this study was to estimate the exercise intensity from the competition heart rate (HR) of professional triathletes during a multi-triathlon race. Five internationally ranked professional triathletes completed incremental cycling and running tests to assess the first and second ventilatory thresholds (i.e., VT and RCT) and the HR at VT and RCT. HR was then monitored during a 5 d multi-triathlon race: a prologue time trial (PTT, 0.2 km swim - 5 km cycle - 1.2 km run) that opened the race; short-distance triathlons (SHD; 1.3 km swim - 36 km cycle - 8.4 km run) performed on the 2nd and 5th days; and sprint-distance triathlons (SPD; 0.75 km swim - 20 km cycle - 5 km run) performed on the 3rd and 4th days. All trials except the last (i.e., the second SHD) were performed above HR corresponding to RCT. PTT elicited significantly higher mean HR than the other trials (except for the first SPD trial). In contrast, the last SHD elicited significantly lower HR than the other trials. These responses were globally similar in the 3 segments (i.e., swim, cycle, and run). This study demonstrates that the triathletes performed at very high intensity during a drafting-permitted multi-triathlon race. However, as shown for multi-day cycling distances, the HR responses depended on (i) the distance covered and (ii) group behavior.Key words: heart rate, ventilatory thresholds, swim, cycle, run.
Can body weight supported treadmill training increase bone mass and reverse muscle atrophy in individuals with chronic incomplete spinal cord injury?
Authors: Giangregorio Lora M , Webber Colin E , Phillips Stuart M , Hicks Audrey L , Craven B Catherine , Bugaresti Joanne M , McCartney Neil
Published: June 2006

This study evaluates the impact of 12 months of body weight supported treadmill training (BWSTT) on muscle and bone in individuals with spinal cord injury (SCI). Fourteen individuals who sustained an incomplete SCI at least 12 months before the study were recruited to participate in BWSTT 3 times/week for a total of 144 sessions. Thirteen individuals completed the study. The average age of subjects was 29 y, average time post-injury was 7.70 y (range: 1-24 y). Areal bone densities of the proximal and distal femur, proximal tibia, spine, and whole body were measured using dual-energy X-ray absorptiometry. Muscle cross-sectional area (CSA), volumetric bone density, and bone geometry at mid-femur and proximal tibia were measured using computed tomography. Serum osteocalcin and urinary deoxypyridinoline were measured at baseline and after 6 and 12 months of training. All other measures were made before and after training. Participants experienced significant increases in whole-body lean mass, from 45.9 ± 8.7 kg to 47.8 ± 8.9 kg (mean ± SD; p < 0.003). Muscle CSAs increased by an average of 4.9% and 8.2% at the thigh and lower leg sites, respectively. No significant changes occurred in bone density or bone geometry at any site, or in bone biochemical markers. Whole-body bone density exhibited a small but statistically significant decrease (p < 0.006). BWSTT may therefore be a promising intervention for increasing muscle mass. Although 12 months of BWSTT did not increase bone density in individuals with chronic incomplete SCI, it did not appear to decrease bone density at fracture-prone sites.Key words: spinal cord injury, bone density, muscle mass, osteoporosis, body weight support.
Longitudinal and radial systolic myocardial tissue velocities after prolonged exercise
Authors: George Keith , Shave Rob , Oxborough David , Whyte Greg , Dawson Ellen
Published: June 2006

We assessed segmental and global left ventricular (LV) systolic function using tissue Doppler imaging (TDI) in 30 subjects (age: 18-62 y) before and after a marathon race. Longitudinal plane systolic (S′) TDI velocities were assessed at 5 sites on the mitral annulus and radial plane S' velocities were assessed at the LV septal and free wall in a subsample (n = 9). Heart rate (HR) and LV diastolic internal dimension were also assessed before (pre) and immediately after (post) the race. Pre-post changes in all variables were analysed by repeated measures analysis of variance (ANOVA). Delta scores for TDI data were correlated with alterations in indices of LV loading, as well as with age and finishing time. Segmental longitudinal and radial TDI velocities were not significantly different pre to post race (p > 0.05), which resulted in no change in mean S′ velocities (longitudinal: pre 17.0 ± 3.4 cm·s-1, post 17.4 ± 4.0 cm·s-1; radial: pre 13.0 ± 5.4 cm·s-1, post 14.2 ± 7.1 cm·s-1; p > 0.05). Any pre-post changes in TDI data were not related to an elevated post race HR (r = 0.15, p > 0.05), a decreased post race LV internal dimension in diastole (r = 0.10, p > 0.05), age (r = -0.25, p > 0.05), or finishing time (r = -0.13, p > 0.05). Our data suggest that marathon running does not induce any segmental or global depression in LV systolic function.Key words: tissue Doppler imaging, cardiac fatigue, echocardiography, marathon.
Reduced glycogen availability is associated with increased AMPKα2 activity, nuclear AMPKα2 protein abundance, and GLUT4 mRNA expression in contracting human skeletal muscle
Authors: Steinberg Gregory R , Watt Matthew J , McGee Sean L , Chan Stanley , Hargreaves Mark , Febbraio Mark A , Stapleton David , Kemp Bruce E
Published: June 2006

Glycogen availability can influence glucose transporter 4 (GLUT4) expression in skeletal muscle through unknown mechanisms. The multisubstrate enzyme AMP-activated protein kinase (AMPK) has also been shown to play an important role in the regulation of GLUT4 expression in skeletal muscle. During contraction, AMPK α2 translocates to the nucleus and the activity of this AMPK isoform is enhanced when skeletal muscle glycogen is low. In this study, we investigated if decreased pre-exercise muscle glycogen levels and increased AMPK α2 activity reduced the association of AMPK with glycogen and increased AMPK α2 translocation to the nucleus and GLUT4 mRNA expression following exercise. Seven males performed 60 min of exercise at ~70% VO2 peak on 2 occasions: either with normal (control) or low (LG) carbohydrate pre-exercise muscle glycogen content. Muscle samples were obtained by needle biopsy before and after exercise. Low muscle glycogen was associated with elevated AMPK α2 activity and acetyl-CoA carboxylase β phosphorylation, increased translocation of AMPK α2 to the nucleus, and increased GLUT4 mRNA. Transfection of primary human myotubes with a constitutively active AMPK adenovirus also stimulated GLUT4 mRNA, providing direct evidence of a role of AMPK in regulating GLUT4 expression. We suggest that increased activation of AMPK α2 under conditions of low muscle glycogen enhances AMPK α2 nuclear translocation and increases GLUT4 mRNA expression in response to exercise in human skeletal muscle.Key words: exercise, subcellular localization, glycogen binding domain, AMP-activated protein kinase.
Urine specific gravity in exercisers prior to physical training
Authors: Stover Elizabeth A , Petrie Heather J , Passe Dennis , Horswill Craig A , Murray Bob , Wildman Robert
Published: June 2006

Urine specific gravity (USG) is used as an index of hydration status. Many studies have used USG to estimate pre-exercise hydration in athletes. However, very little is known about the pre-exercise hydration status of recreational exercisers. The purpose of the present study was to measure the pre-exercise USG in a large sample of recreational exercisers who attended 2 different fitness centers in the United States. In addition, we wanted to determine if factors such as time of day, geographic location, and gender influenced USG. We tested 166 subjects in Chicago and 163 subjects in Los Angeles. Subjects completed a survey on their typical training regimen and fluid-replacement habits, and thereafter voided and delivered a urine sample to the investigators prior to beginning exercise. Samples were measured on site for USG using a hand-held refractometer. The mean (SD) USG was 1.018 (± 0.007) for all subjects. Males had a higher average USG (1.020 ± 0.007) when compared with females (1.017 ± 0.008; p = 0.001). Despite differences in climate, no difference in mean USG occurred based on location or time of day. Based on standards used for athletes (USG >= 1.020), 46% of the exercisers were likely to be dehydrated.Key words: dehydration, exercise, hydration.
Physiological profile of professional hockey players - a longitudinal comparison
Authors: Montgomery David L
Published: June 2006

This paper examines the size, strength, and aerobic fitness of players from a professional hockey team. Beginning in 1917, data on body size were obtained from historical records of the Montreal Canadiens. Body composition, strength, and VO2 max were obtained through physiological testing of Canadiens players between 1981 and 2003. Compared with players in the 1920s and 1930s, current players were an average of 17 kg heavier and 10 cm taller, with BMI increased by 2.3 kg/m2. The gain in BMI was not attributed to added fat mass, since percent body fat remained unchanged over the past 22 years. From 1992 to 2003, upper body strength was assessed using a bench press test. Predicted 1 repetition maximum (1 RM) for the 17- to 19-year-old group was 107.0 kg with the highest values attained by the 25- to 29-year-old age group (128.1 kg). Gains in body mass were associated with an increase in upper body strength. VO2 max was measured annually on a treadmill between 1992 and 2003 with annual mean values ranging between 54.6 and 59.2 mL·(kg·min)-1. Compared with values from players in the early 1980s, VO2 max has increased with the improvements independent of body mass; however, given the variability in the data, we are hesitant to infer that VO2 max has increased significantly during the 1990s.Key words: physiological assessment, strength, aerobic power, professional hockey players.
ACCURACY OF PROTON CHARGE DETERMINATION BY AR YIELD MEASUREMENTS AT IN-AIR PIXE
Authors: BUDNAR M. , SIMČIČ J. , PELICON P. , RUPNIK Z.
Published: June 2006

Determination of proton charge during in-air PIXE experiments can be hampered when analysing thick non-conductive samples. Several arrangements may be used for overcoming this problem, while in studies of historical documents a variant employing X-ray yield measurements on Ar in air is often used. At compact geometry, with a small distance from the exit foil to the sample (10 mm or less), and also with close location of the X-ray detector to the sample to increase the detector solid angle, the uncertainties in the experimental geometry directly influence the accuracy of the PIXE analysis. The factors affecting the accuracy when using Ar yields are estimated. The advantage of the other technique, measuring X-ray radiation from the exit foil, is elaborated.
PIXE STUDIES OF SOME HUMAN STONES
Authors: SHARAT SINGH N. K. , SARMA H. N. K. , SUDARSHAN M. , CHAKRABORTY A.
Published: June 2006

Stones removed from different patients of different ages were collected at Regional Institute of Medical Sciences, Imphal, North-eastern India. The stones were analyzed by PIXE with 3MeV protons. Ca was found to be the major constituent element. Light elements present in minor concentration were S , Cl and K . Again, Fe , Ni , Cu , Zn , Sr were observed in low concentration and most of them were detected in trace levels.
PIXE ANALYSIS OF TRACE ELEMENTS IN HUMAN HAIR OF PATIENTS WITH LIVER DISORDERS
Authors: BOLORMAA O. , TSUJI M. , KAWASAKI K. , NARANTSETSEG S. , HATTORI T.
Published: June 2006

Human hairs of cirrhosis, acute viral hepatitis patients and healthy people in Ulaanbaatar, capital city of Mongolia, were analyzed for the presence of heavy elements by PIXE spectrometry using 2.5 MeV proton beam at the Tokyo Institute of Technology Van de Graaff Laboratory. The samples were dissolved in a mixture of nitric acid and hydrogen peroxide. Then a 20μl aliquot was dropped on a Nuclepore Track-etch Membrane. The IAEA Reference Hair IAEA-086 certified reference material was used in order to verify accuracy of the method and the results were in good agreement with the certified values. To determine the interaction among nine elements in hair, correlation coefficients were evaluated for several pairs of elements. In the group of healthy control, no correlation between elements was identified. Opposite to this, the strong positive correlations were observed for Zn and Ca or Fe ; Mn and Ca or Ti ; Sr and Zn or Fe in the patients hair. In the present study, the mean concentrations of Ca , Ti , As and Sr in Mongolian patients were higher than those in the hair of normal people in Japan, Mongolia, Iran and Indonesia. The levels of Cu , Zn and Mn concentration in hair of normal people were almost the same for all the cohorts.
PIXE ANALYSIS OF SPOT SAMPLES ON NEW TYPE OF PTFE ULTRA-MEMBRANE FILTER-TAPE MOUNTED IN AN AUTOMATED BETA-RAY ABSORPTION MASS MONITOR
Authors: SAITOH KATSUMI , SERA KOICHIRO , IMASEKI HITOSHI , SHINOHARA MASYASHI , FUJIWARA MASAHIKO
Published: June 2006

In order to obtain high time-resolution, i.e., chemical data of atmospheric particulate matter (PM) at one-hour intervals, we carried out direct analysis of suspended particulate matter (SPM) on hourly spot samples on a new type of PTFE ultra-membrane filter-tape mounted in an automated beta-ray absorption mass monitor by conventional PIXE. Analysis of hourly SPM spot samples revealed 20 elements ( Na , Mg , Al , Si , S , Cl , K , Ca , Mn , Fe , Co , Ni , Cu , Zn , Ga , As , Se , Br , Sr and Pb ) in total. Therefore, we are convinced that the chemical information that is obtained from high time-resolution PM spot samples on a PTFE membrane filter-tape mounted in an automated beta-ray absorption mass monitor will lead to new developments in PM research. Furthermore, elemental data obtained by the high time-resolution along with data for ionic species compositions, and SO 2, NO X and other gaseous air pollutants at the same level, will make possible the analysis of detailed air pollution phenomenon.
PIXE ANALYSIS OF BIOLOGICAL SAMPLES FOR ASSESSING AIRBORNE ELEMENTS AT GROUND LEVEL
Authors: PACHECO ADRIANO M. G. , DO CARMO FREITAS MARIA
Published: June 2006

Biological monitoring through higher plants should be more than just a second choice for air-quality assessment in polluted or dry areas that happen to be devoid of lichens and/or bryophytes. Provided that some of their specifics are accounted for, vascular plants could indeed stand for an actual alternative to lower epiphytes, if not featuring some real advantages – technical, economical and ecological – over them. As a contribution to an evaluation of such an alternative, olive trees (Olea europaea Linn.) have been sampled for their outer bark across two separate areas of mainland Portugal, in a total of 53 collection locations. After suitable procedures, bark samples were put through proton-induced X-ray emission (PIXE) and analyzed for their elemental contents. Nonparametric coefficients (Kendall's) for the spatial variation of S , Ni , Cu and Pb are significant beyond any reasonable, statistical level. There is also a good spatial agreement – sometimes, an excellent one – with lichen trends as an external reference, but for lead, that may suffer from spectral interference though. Further research on material cleansing and pelletising procedures is advisable, especially in what concerns the homogeneity of bark samples for PIXE analysis.
STUDY OF THE PUREPECHA METALS BY PIXE AND METALLOGRAPHY TECHNIQUES
Authors: MÉNDEZ U. , TENORIO D. , MURILLO G. , MÉNDEZ-GARRIDO B. , LONGORIA LUIS C. , LÓPEZ J. A.
Published: June 2006

Proton-Induced-X-Ray-Emission (PIXE) is a suitable technique for the elemental analysis of ancient metallic artifacts, without any deterioration of the samples. Metallography was used to determine the manufacture technique of ancient metallic artifacts. These techniques were applied to study 12 copper artifacts collected, from burial offerings of a "Señor Tarasco", discovered by Eduardo Pareyon, in "El Portal de Matamoros", Uruapan, Michoacán, in 1957.
THE FULL BROWNIAN WEB AS SCALING LIMIT OF STOCHASTIC FLOWS
Authors: FONTES LUIZ RENATO , NEWMAN CHARLES M.
Published: June 2006

In this paper we construct an object which we call the full Brownian web (FBW) and prove that the collection of all spacetime trajectories of a class of one-dimensional stochastic flows converges weakly, under diffusive rescaling, to the FBW. The (forward) paths of the FBW include the coalescing Brownian motions of the ordinary Brownian web along with bifurcating paths. Convergence of rescaled stochastic flows to the FBW follows from general characterization and convergence theorems that we present here combined with earlier results of Piterbarg.
STOCHASTIC CAHN–HILLIARD PARTIAL DIFFERENTIAL EQUATIONS WITH LÉVY SPACETIME WHITE NOISES
Authors: BO LIJUN , WANG YONGJIN
Published: June 2006

In this paper, we consider a class of stochastic Cahn–Hilliard partial differential equations driven by Lévy spacetime white noises with Neumann boundary conditions. By a dedicate construction we prove that a (unique) local solution exists for the SPDE under some mild assumptions on the coefficients.
ISOMORPHISMS BETWEEN QUANTUM GENERALIZED WEYL ALGEBRAS
Authors: RICHARD LIONEL , SOLOTAR ANDREA
Published: June 2006

We study isomorphisms between generalized Weyl algebras, giving a complete answer to the quantum case of this problem for R = k[h].
ARTICULATIONS OF ALGEBRAS AND THEIR HOMOLOGICAL PROPERTIES
Authors: DIONNE JULIE , SMITH DAVID
Published: June 2006

We give a construction of algebras, called articulation, which is a specific gluing of two non-simple algebras. Then, we describe the Auslander–Reiten theory of an algebra obtained in this way. This allows us to characterize the articulated algebras which are laura, left (or right) glued, weakly shod, shod, quasi-tilted or tilted.
NON-COMMUTATIVE DUPLICATES OF FINITE SETS
Authors: CIBILS CLAUDE
Published: June 2006

We classify the twisted tensor products of a finite set algebra with a two elements set algebra using colored quivers obtained through considerations analogous to Ore extensions. This provides also a classification of entwining structures between a finite set algebra and the grouplike coalgebra on two elements. The resulting 2-nilpotent algebras have particular features with respect to Hochschild (co)homology and cyclic homology.
Virus Counterdefense: Diverse Strategies for Evading the RNA-Silencing Immunity
Authors: Li Feng , Ding Shou-Wei
Published: June 2006

Viruses are obligate, intracellular pathogens that must manipulate and exploit host molecular mechanisms to prosper in the hostile cellular environment. Here we review the strategies used by viruses to evade the immunity controlled by 21- to 26-nt small RNAs. Viral suppressors of RNA silencing (VSRs) are encoded by genetically diverse viruses infecting plants, invertebrates, and vertebrates. VSRs target key steps in the small RNA pathways by inhibiting small RNA production, sequestering small RNAs, or preventing short- and long-distance spread of RNA silencing. However, although VSRs are required for infection, explicit data demonstrating a role of silencing suppression in virus infection are available only for a few VSRs. A subset of VSRs bind double-stranded RNA, but a distinct protein fold is revealed for each of the four VSRs examined. We propose that VSR families are evolved independently as a viral adaptation to immunity. Unresolved issues on the role of RNA silencing in virus-host interactions are highlighted.
ADAMs as mediators of EGF receptor transactivation by G protein-coupled receptors
Authors: Ohtsu Haruhiko , Dempsey Peter J. , Eguchi Satoru
Published: June 2006

A disintegrin and metalloprotease (ADAM) is a membrane-anchored metalloprotease implicated in the ectodomain shedding of cell surface proteins, including the ligands for epidermal growth factor (EGF) receptors (EGFR)/ErbB. It has been well documented that the transactivation of the EGFR plays critical roles for many cellular functions, such as proliferation and migration mediated through multiple G protein-coupled receptors (GPCRs). Recent accumulating evidence has suggested that ADAMs are the key metalloproteases activated by several GPCR agonists to produce a mature EGFR ligand leading to the EGFR transactivation. In this review, we describe the current knowledge on ADAMs implicated in mediating EGFR transactivation. The major focus of the review will be on the possible upstream mechanisms of ADAM activation by GPCRs as well as downstream signal transduction and the pathophysiological significances of ADAM-dependent EGFR transactivation.
Local disruption of the celiac ganglion inhibits substance P release and ameliorates caerulein-induced pancreatitis in rats
Authors: Noble Marc D. , Romac Joelle , Wang Yu , Hsu Jay , Humphrey John E. , Liddle Rodger A.
Published: June 2006

Primary sensory neurons of the C and Aδ subtypes express the vanilloid capsaicin receptor TRPV1 and contain proinflammatory peptides such as substance P (SP) that mediate neurogenic inflammation. Pancreatic injury stimulates these neurons causing the release of SP in the pancreas resulting in pancreatic edema and neutrophil infiltration that contributes to pancreatitis. Axons of primary sensory neurons innervating the pancreas course through the celiac ganglion. We hypothesized that disruption of the celiac ganglion by surgical excision or inhibition of C and Aδ fibers through blockade of TRPV1 would reduce the severity of experimental pancreatitis by inhibiting neurogenic inflammation. Resiniferatoxin (RTX) is a specific TRPV1 agonist that, in high doses, selectively destroys C and Aδ fibers. Sprague-Dawley rats underwent surgical ganglionectomy or application of 10 μg RTX (vs. vehicle alone) to the celiac ganglion. One week later, pancreatitis was induced by six hourly intraperitoneal injections of caerulein (50 μg/kg). The severity of pancreatitis was assessed by serum amylase, pancreatic edema, and pancreatic myeloperoxidase (MPO) activity. SP receptor (neurokinin-1 receptor, NK-1R) internalization in acinar cells, used as an index of endogenous SP release, was assessed by immunocytochemical quantification of NK-1R endocytosis. Caerulein administration caused significant increases in pancreatic edema, serum amylase, MPO activity, and NK-1R internalization. RTX treatment and ganglionectomy significantly reduced pancreatic edema by 46% ( P < 0.001) and NK-1R internalization by 80% and 51% ( P < 0.001 and P < 0.05, respectively). RTX administration also significantly reduced MPO activity by 47% ( P < 0.05). Neither treatment affected serum amylase, consistent with a direct effect of caerulein. These results demonstrate that disruption of or local application of RTX to the celiac ganglion inhibits SP release in the pancreas and reduces the severity of acute secretagogue-induced pancreatitis. It is possible that selectively disrupting TRPV1-bearing neurons could be used to reduce pancreatitis severity.
Bone morphogenetic protein signaling and growth suppression in colon cancer
Authors: Beck Stayce E. , Jung Barbara H. , Fiorino Antonio , Gomez Jessica , Rosario Eunice Del , Cabrera Betty L. , Huang Sherry C. , Chow Jimmy Y. C. , Carethers John M.
Published: June 2006

Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-β superfamily, which utilize BMP receptors and intracellular SMADs to transduce their signals to regulate cell differentiation, proliferation, and apoptosis. Because mutations in BMP receptor type IA ( BMPRIA) and SMAD4 are found in the germline of patients with the colon cancer predisposition syndrome juvenile polyposis, and because the contribution of BMP in colon cancers is largely unknown, we examined colon cancer cells and tissues for evidence of BMP signaling and determined its growth effects. We determined the presence and functionality of BMPR1A by examining BMP-induced phosphorylation and nuclear translocation of SMAD1; transcriptional activity via a BMP-specific luciferase reporter; and growth characteristics by cell cycle analysis, cell growth, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide metabolic assays. These assays were also performed after transfection with a dominant negative (DN) BMPR1A construct. In SMAD4-null SW480 cells, we examined BMP effects on cellular wound assays as well as BMP-induced transcription in the presence of transfected SMAD4. We also determined the expression of BMPR1A, BMP ligands, and phospho-SMAD1 in primary human colon cancer specimens. We found intact BMP signaling and modest growth suppression in HCT116 and two derivative cell lines and, surprisingly, growth suppression in SMAD4-null SW480 cells. BMP-induced SMAD signaling and BMPR1A-mediated growth suppression were reversed with DN BMPR1A transfection. BMP2 slowed wound closure, and transfection of SMAD4 into SW480 cells did not change BMP-specific transcriptional activity over controls due to receptor stimulation by endogenously produced ligand. We found no cell cycle alterations with BMP treatment in the HCT116 and derivative cell lines, but there was an increased G1fraction in SW480 cells that was not due to increased p21 transcription. In human colon cancer specimens, BMP2 and BMP7 ligands, BMPRIA, and phospho-SMAD1 were expressed. In conclusion, BMP signaling is intact and growth suppressive in human colon cancer cells. In addition to SMADs, BMP may utilize SMAD4-independent pathways for growth suppression in colon cancers.
X-ray backscatter imaging: Photography through barriers
Authors: Callerame Joseph
Published: June 2006

X-ray imaging techniques based on Compton backscatter permit inspection and screening of sea containers, a wide variety of vehicles, luggage, and even people. In contrast to more commonly used transmission images, backscatter imaging involves positioning both source and detection apparatus on only one side of a target object. This presents the user with inspection opportunities in situations that may be extremely difficult, if not impossible, for transmission systems that require access by the detector subsystem to the opposing side of the target. The backscatter image is somewhat akin to a photograph of the contents of a closed container, taken through the container walls. Techniques for producing X-ray images based on Compton scattering will be discussed, along with wide-ranging examples of how systems based on these principles are used to perform inspections for both security applications and for the detection of contraband materials at ports and borders. Potential applications in the area of nondestructive evaluation will also be considered. Differences in the type of information displayed by transmission and backscatter images will be highlighted, and tradeoffs between backscatter image quality and interpretability, scan speed, effective penetration, and X-ray tube voltage will also be discussed. The method used in scanning the target object results in an extremely low radiation dose, a result that significantly broadens the application spectrum for this imaging technique.
Characterizing process semiconductor thin films with a confocal micro X-ray fluorescence microscope
Authors: Sparks Chris M. , Hastings Elizabeth P. , Havrilla George J. , Beckstead Michael
Published: June 2006

The versatility of confocal micro X-ray fluorescence (MXRF) in analyzing thin films on semiconductor wafers is demonstrated. Unlike conventional MXRF, confocal MXRF can depth profile sample layers and reduce spectral background. Nondestructive quantification of the silicon dioxide concentration in hafnium silicate thin films is an example of one application demonstrating the advantage of confocal MXRF. Additionally, the growth of titanium nitride films on various high-k gate dielectric substrates was analyzed with confocal MXRF due to its ability to detect sub-nm film thickness changes.
Three-dimensional Interactive Data Language pole figure visualization
Authors: Frazer Colleen S. , Rodriguez Mark A. , Tissot Ralph G.
Published: June 2006

The Interactive Data Language has been used to produce a software program capable of advanced three-dimensional visualizations of pole figure and θ-2θ data. The data can also be used to calculate quantitative properties such as strain level and to minimize the peak-height texture effects in individual θ-2θ scans. The collection of the large data sets necessary for the analyses is facilitated by use of a position sensitive detector or area detector.
Developments in formulation analyses by powder diffraction analysis
Authors: Fawcett T. G. , Faber J. , Needham F. , Kabekkodu S. N. , Hubbard C. R. , Kaduk J. A.
Published: June 2006

Developments in X-ray analysis hardware and software have combined to dramatically improve the throughput, speed, and accuracy of formulation analyses. We will focus on a complimentary development, the growth and application of a comprehensive database based on the Powder Diffraction File™ (PDF®). The PDF is an edited and standardized combination of several crystallographic databases with ∼497 000 published entries. The comprehensive nature of this database, combined with phase identification and digital pattern simulations, was used to identify complex formulations with crystalline and noncrystalline ingredients. We will show how these parallel developments enhance the ability to correctly identify complex formularies.
Concordant Association of Lipid Gene Variation with a Combined HDL/LDL-Cholesterol Phenotype in Two European Populations
Authors: Bauerfeind Anja , Knoblauch Hans , Costanza Michael C. , Luganskaja Tatjana , Toliat Mohammad R. , Nürnberg Peter , Luft Friedrich C. , Reich Jens G. , Morabia Alfredo
Published: June 2006

Objective: SNP/phenotype associations are difficult to validate. This comparative study demonstrates significant contribution of candidate genes to the variation of a complex cholesterol phenotype, measured in two general populations by a gene-based approach. Methods: Independent samples of normolipidemic subjects from two Caucasian populations (371 Swiss and 157 Germans) were selected for a case-control-study (high LDL/low HDL versus low LDL/high HDL) with SNP genotypes as independent factors. We examined locus-specific common SNPs that densely cover the genomic regions of 10 lipid genes. Results: Genotype effects were concordant in both ethnic samples, showing that APOE, ABCA1, CETP, and to a lesser degree LDLR, LIPC, and PLTP explained a substantial part of the genetic variation, whereas LPL was associated in only one sample. APOA1, LCAT, and SRB1 exerted no measurable influence. Conclusion: This comparison showed that sets of common SNPs representing candidate regions reproducibly validate significant linkage disequilibrium association with a complex metabolic trait.
Thermometers: Something for Statistical Geneticists to Think about
Authors: Vieland Veronica J.
Published: June 2006

In human genetics, we measure the strength of statistical evidence using a variety of maximized likelihood ratios, LODs, and empirical p values. I argue here that these statistics have highly undesirable properties as evidence measures when applied to complex disorders. Among other deficiencies, I show that when following up on an interesting finding, they will tend to erroneously indicate diminished evidence as more data are considered (e.g., the LOD will tend to go down at a linked locus as the sample size increases). This violates a fundamental assumption underlying standard linkage and association designs in which we first scan the genome for our best signals, and then follow up at those genomic positions with additional data. I argue here for a coherent theoretical approach to formalizing statistical evidence measures, and derive a set of minimal requirements that any evidence measure should meet, drawing heavily on an analogy with the thermometer. I speculate that measures of evidence that come closer to meeting these requirements will do a better job of finding and characterizing genes, and I propose an alternative evidence metric as a step in this direction.
Memory for Choices in Alzheimer’s Disease
Authors: Budson Andrew E. , Mather Mara , Chong Hyemi
Published: June 2006

Despite their cognitive impairment, patients with mild Alzheimer’s disease (AD) often make important life choices. When making choices, people frequently attempt to directly compare the features of different options, rather than evaluating each option separately. Not every feature has an analogous (or alignable) feature in the other option, however. In 2005, Mather’s group found that both younger and older adults filled in such gaps when remembering, creating features in the other option to contrast with existing features. In the present study, such effects of alignability on recognition memory were not found in patients with mild AD. This finding suggests that patients with mild AD are less likely to engage in feature-by-feature comparison processes across choice options, a change that may lead them to make qualitatively different choices than healthy older adults.
Evaluating Spousal Abuse as a Potential Risk Factor for Alzheimer’s Disease: Rationale, Needs and Challenges
Authors: Leung Fok-Han , Thompson Kara , Weaver Donald F.
Published: June 2006

Background: Repetitive head trauma is an identified risk factor for Alzheimer’s disease (AD). The violence in wife assault is repetitive and targets the head. This association provides a rationale for studying the relationship between spousal abuse and AD. Design: To preliminarily evaluate the possibility of an increased susceptibility for AD in women subjected to spousal abuse and to identify challenges associated with such a study, we performed a pilot case-control study involving women with AD and compared the incidence of spousal abuse against two control groups. Forty consecutive women with AD referred to a Memory Disorders Clinic were enrolled. Individuals were evaluated at three visits (0, 3, 9 months) and were followed for an additional 12 months to ensure that no other diagnosis emerged. Two control groups were likewise assessed. Results: 17.5% (7/40) of the women (average age 71 years) with AD reported spousal abuse with head trauma. In control group 1, 5.0% (2/40) and in control group 2, 7.5% (3/40) of the women reported spousal abuse with head trauma. Conclusions: The development of AD may be a potential long-term consequence of wife assault. Our study suggests spousal abuse as a possible risk factor for AD, and supports the need for larger studies. However, there are practical challenges associated with the successful execution of such a study.
Critical Time Window for Intra-Arrest Cooling With Cold Saline Flush in a Dog Model of Cardiopulmonary Resuscitation
Authors: Nozari Ala , Safar Peter , Stezoski S. William , Wu Xianren , Kostelnik Scott , Radovsky Ann , Tisherman Samuel , Kochanek Patrick M.
Published: June 2006

Background—

Mild hypothermia improves outcome when induced after cardiac arrest in humans. Recent studies in both dogs and mice suggest that induction of mild hypothermia during cardiopulmonary resuscitation (CPR) greatly enhances its efficacy. In this study, we evaluate the time window for the beneficial effect of intra-arrest cooling in the setting of prolonged CPR in a clinically relevant large-animal model.

Methods and Results—

Seventeen dogs had ventricular fibrillation cardiac arrest no flow of 3 minutes, followed by 7 minutes of CPR basic life support and 50 minutes of advanced life support. In the early hypothermia group (n=9), mild hypothermia (34°C) was induced with an intravenous fluid bolus flush and venovenous blood shunt cooling after 10 minutes of ventricular fibrillation. In the delayed hypothermia group (n=8), hypothermia was induced at ventricular fibrillation 20 minutes. After 60 minutes of ventricular fibrillation, restoration of spontaneous circulation was achieved with cardiopulmonary bypass for 4 hours, and intensive care was given for 96 hours. In the early hypothermia group, 7 of 9 dogs survived to 96 hours, 5 with good neurological outcome. In contrast, 7 of 8 dogs in the delayed hypothermia group died within 37 hours with multiple organ failure (
P
=0.012).

Conclusions—

Early application of mild hypothermia with cold saline during prolonged CPR enables intact survival. Delay in the induction of mild hypothermia in this setting markedly reduces its efficacy. Our data suggest that if mild hypothermia is used during CPR, it should be applied as early as possible.
Explicitly Accounting for Observation Error in Categorical Verification of Forecasts
Authors: Bowler Neill E.
Published: June 2006

Given an accurate representation of errors in observations it is possible to remove the effect of those errors from categorical verification scores. The errors in the observations are treated as additive white noise that is statistically independent of the true value of the quantity being observed. This method can be applied to both probabilistic and deterministic verification where the verification method uses a categorical approach. In general this improves the apparent performance of a forecasting system, indicating that forecasting systems are often performing better than they might first appear.
Numerical Forecasts of the 15–16 June 2002 Southern Plains Mesoscale Convective System: Impact of Mesoscale Data and Cloud Analysis
Authors: Dawson Daniel T. , Xue Ming
Published: June 2006

High-resolution explicit forecasts using the Advanced Regional Prediction System (ARPS) of the 15–16 June 2002 mesoscale convective system (MCS) that occurred over the U.S. central and southern plains during the International H2O Project (IHOP_2002) field experiment period are performed. The forecasts are designed to investigate the impact of mesoscale and convective-scale data on the initialization and prediction of an organized convective system. Specifically, the forecasts test the impact of special mesoscale surface and upper-air data collected by, but not necessarily specific to, IHOP_2002 and of level-II data from multiple Weather Surveillance Radar-1988 Doppler radars. The effectiveness of using 30-min assimilation cycles with the use of a complex cloud-analysis procedure and high-temporal-resolution surface data is also examined. The analyses and forecasts employ doubly nested grids, with resolutions of 9 and 3 km. Emphasis is placed on the solutions of the 3-km grid. In all forecasts, a strong, well-defined bow-shaped MCS is produced with structure and behavior similar to those of the observed system. Verification of these forecasts through both regular and phase-shifted equitable threat scores of the instantaneous composite reflectivity fields indicate that the use of the complex cloud analysis has the greatest positive impact on the prediction of the MCS, primarily by removing the otherwise needed “spinup” time of convection in the model. The impact of additional data networks is smaller and is reflected mainly in reducing the spinup time of the MCS too. The use of intermittent assimilation cycles appears to be quite beneficial when the assimilation window covers a time period when the MCS is present. Difficulties with verifying weather systems with high spatial and temporal intermittency are also discussed, and the use of both regular and spatially shifted equitable threat scores is found to be very beneficial in assessing the quality of the forecasts.