bluuebunny/crossref_metadata_2025 huggingface dataset:
Splenic reflex modulation of central cardiovascular regulatory pathways
Authors: Moncrief Karli , Hamza Shereen , Kaufman Susan
Published: March 2007

The splenorenal reflex induces changes in mean arterial pressure (MAP) and renal function. We hypothesized that, in addition to spinal pathways previously identified, these effects are also mediated through central pathways. We investigated the effect of elevated splenic venous pressure on central neural activation in intact, renal-denervated, and renal + splenic-denervated rats. Fos-labeled neurons were quantified in the nucleus of the tractus solitarius (NTS), paraventricular nucleus (PVN), supraoptic nucleus (SON), and subfornical organ (SFO) after 1-h partial splenic vein occlusion (SVO) in conscious rats bearing balloon occluders around the splenic vein, telemetric pressure transducers in the gastric vein (splenic venous pressure), and abdominal aorta catheters (MAP). SVO stimulated Fos expression in the PVN and SON, but not NTS or SFO of intact rats. Renal denervation abolished this response in the parvocellular PVN, while renal + splenic denervation abolished activation in the magnocellular PVN and the SON. In renal-denervated animals, SVO depressed Fos expression in the NTS and increased expression in the SFO, responses that were abolished by renal + splenic denervation. In intact rats, SVO also induced a fall in right atrial pressure, an increase in renal afferent nerve activity, and an increase in MAP. We conclude that elevated splenic venous pressure does induce hypothalamic activation and that this is mediated through both splenic and renal afferent nerves. However, in the absence of renal afferent input, SVO depressed NTS activation, probably as a result of the accompanying fall in cardiac preload and reduced afferent signaling from the cardiopulmonary receptors.
LBNP treadmill exercise maintains spine function and muscle strength in identical twins during 28-day simulated microgravity
Authors: Macias Brandon R. , Cao Peihong , Watenpaugh Donald E. , Hargens Alan R.
Published: March 2007

The purpose of this study was to determine whether lower body negative pressure (LBNP) treadmill exercise maintains lumbar spinal compressive properties, curvature, and back muscle strength after 28 days of 6° head-down tilt (HDT) bed rest (BR). We hypothesize that LBNP treadmill exercise will maintain lumbar spine compressibility, lumbar lordosis and back muscle strength after 28 days of 6° HDT bed rest. Fifteen healthy identical twin pairs (14 women and 16 men) participated in this study. One identical twin was randomly assigned to the nonexercise control (Con) group, and their sibling was assigned to the exercise (Ex) group. The lumbar spine was significantly more compressible Post-BR compared with Pre-BR in the Con ( P = 0.01). Lumbar spine compressibility Post-BR was not significantly different compared with Pre-BR in the Ex group ( P = 0.89). In both the Con and Ex groups, there were no significant changes Post-BR in lumbar lordosis compared with Pre-BR. Back muscle strength significantly decreased in the Con group Post-BR ( P = 0.002), whereas in the Ex group back muscle strength was not significantly different from Pre-BR values. A significant increase in lumbar spine compressibility in the Con group suggests that spinal deconditioning to gravity occurs during 28-day bed rest. Changes in the mechanical properties of the lumbar spine may be an early indicator of lumbar intervertebral disk degeneration. Supine LBNP treadmill exercise provides axial loads to the lumbar spine and may prevent lumbar spine deconditioning associated with HDT bed rest.
Context-Dependent Effects of Substantia Nigra Stimulation on Eye Movements
Authors: Basso Michele A. , Liu Ping
Published: March 2007

In a series of now classic experiments, an output structure of the basal ganglia (BG)—the substantia nigra pars reticulata (SNr)—was shown to be involved in the generation of saccades made in particular behavioral contexts, such as when memory was required for guidance. Recent electrophysiological experiments, however, call this original hypothesis into question. Here we test the hypothesis that the SNr is involved preferentially in nonvisually guided saccades using electrical stimulation. Monkeys performed visually guided and memory-guided saccades to locations throughout the visual field. On 50% of the trials, electrical stimulation of the SNr occurred. Stimulation of the SNr altered the direction, amplitude, latency, and probability of saccades. Visually guided saccades tended to be rotated toward the field contralateral to the side of stimulation, whereas memory-guided saccades tended to be rotated toward the hemifield ipsilateral to the side of stimulation. Overall, the changes in saccade vector direction were larger for memory-guided than for visually guided saccades. Both memory- and visually guided saccades were hypometric during stimulation trials, but the stimulation preferentially affected the length of memory-guided saccades. Electrical stimulation of the SNr produced decreases in visually guided saccades bilaterally. In contrast, memory-guided saccades often had increases in saccade latency bilaterally. Finally, we found approximately 10% reduction in the probability of memory-guided saccades bilaterally. Visually guided saccade probability was unaltered. Taken together the results are consistent with the hypothesis that SNr primarily influences nonvisually guided saccades. The pattern of stimulation effects suggests that SNr influence is widespread, altering the pattern of activity bilaterally across the superior colliculus map of saccades.
Temporal Integration by Stochastic Recurrent Network Dynamics With Bimodal Neurons
Authors: Okamoto Hiroshi , Isomura Yoshikazu , Takada Masahiko , Fukai Tomoki
Published: March 2007

Temporal integration of externally or internally driven information is required for a variety of cognitive processes. This computation is generally linked with graded rate changes in cortical neurons, which typically appear during a delay period of cognitive task in the prefrontal and other cortical areas. Here, we present a neural network model to produce graded (climbing or descending) neuronal activity. Model neurons are interconnected randomly by AMPA-receptor–mediated fast excitatory synapses and are subject to noisy background excitatory and inhibitory synaptic inputs. In each neuron, a prolonged afterdepolarizing potential follows every spike generation. Then, driven by an external input, the individual neurons display bimodal rate changes between a baseline state and an elevated firing state, with the latter being sustained by regenerated afterdepolarizing potentials. When the variance of background input and the uniform weight of recurrent synapses are adequately tuned, we show that stochastic noise and reverberating synaptic input organize these bimodal changes into a sequence that exhibits graded population activity with a nearly constant slope. To test the validity of the proposed mechanism, we analyzed the graded activity of anterior cingulate cortex neurons in monkeys performing delayed conditional Go/No-go discrimination tasks. The delay-period activities of cingulate neurons exhibited bimodal activity patterns and trial-to-trial variability that are similar to those predicted by the proposed model.
Existence and Multiplicity of Positive Solutions for Dirichlet Problems in Unbounded Domains
Authors: Wu Tsung-Fang
Published: March 2007

We consider the elliptic problem−Δu+u=b(x)|u|p−2u+h(x)inΩ,u∈H01(Ω), where2
0as|x|→∞andb(x)≥cfor some suitable constantsc∈(0,b∞), andh(x)≡0. Furthermore, we prove that the above elliptic problem has multiple positive solutions if the coefficientb(x)also satisfies the above conditions,h(x)≥0and0<‖h‖H−1<(p−2)(1/(p−1))(p−1)/(p−2)[bsupSp(Ω)]1/(2−p), whereS(Ω)is the best Sobolev constant of subcritical operator inH01(Ω)andbsup=supx∈Ωb(x).
Generalized Stability ofC*-Ternary Quadratic Mappings
Authors: Park Choonkil , Cui Jianlian
Published: March 2007

We prove the generalized stability ofC*-ternary quadratic mappings inC*-ternary rings for the quadratic functional equationf(x+y)+f(x−y)=2f(x)+2f(y).
On Weighted Hadamard-Type Singular Integrals and Their Applications
Authors: Xu Yong Jia
Published: March 2007

By means of an expression with a kind of integral operators, some properties of the weighted Hadamard-type singular integrals are revealed. As applications, the solution for certain strongly singular integral equations is discussed and illustrated.
Permanence for a Generalized Discrete Neural Network System
Authors: Stevic Stevo
Published: March 2007

We prove that the system of difference equationsxn+1(i)=λixn(i)+fi(αixn(i+1)−βixn−1(i+1)),i∈{1,2,…,k},n∈ℕ, (we regard thatxn(k+1)=xn(1)) is permanent, provided thatαi≥βi,λi+1∈[0,βi/αi),i∈{1,2,…,k},fi:ℝ→ℝ,i∈{1,2,…,k}, are nondecreasing functions bounded from below and such that there areδi∈(0,1)andM>0such thatfi(αix)≤δix,i∈{1,2,…,k}, for allx≥M. This result considerably extends the results existing in the literature. The above system is an extension of a two-dimensional discrete neural network system.
Distinction of Neurochemistry between the Cores and Their Shells of Auditory Nuclei in Tetrapod Species
Authors: Zeng ShaoJu , Li Jia , Zhang XinWen , Zuo MingXue
Published: March 2007

The distribution of Met-enkephalin (ENK), substance P (SP) and serotonin (5-HT) differs between the core and shell regions of the mesencephalic and diencephalic auditory nuclei of the turtle [Belekhova et al., 2002]. These neurochemical distinctions are also found in other tetrapods (mammals, birds and amphibians). The distribution of ENK, SP and 5-HT was examined in the core and shell regions of both mesencephalic and diencephalic auditory nuclei, and in the telencephalic auditory areas of Bengalese finches (Lonchura striata) and mice (Mus musculus), as well as in corresponding auditory areas in toads (Bufo bufo). ENK, SP and 5-HT immunoreactive fibers and perikarya were largely absent from the core regions of both mesencephalic and diencephalic auditory nuclei, in comparison with the shell regions of mice and Bengalese finches. In the toad, however, this pattern was observed in the mesencephalic auditory nucleus, but not in the diencephalic auditory areas. ENK and SP immunoreactive perikarya were detected in the telencephalic auditory area of mice, whereas no ENK, SP or 5-HT immunolabeling was observed in the telencephalic auditory area (Field L) of Bengalese finches. These findings are discussed in terms of the evolution of the core-and-shell organization of auditory nuclei of tetrapods.
Effects of Maturation on Parameters Used for Pass/Fail Criteria in Neonatal Hearing Screening Programmes Using Evoked Otoacoustic Emissions
Authors: Sadri Maziar , Thornton A. Roger D. , Kennedy Colin R.
Published: March 2007

We aimed to investigate the incidence of false alarms that occurred with the pass/fail criteria used in a published series of neonatal hearing screening programmes, as a function of age. We analysed the database of 19137 normally hearing babies (38274 ears) tested in the Wessex Universal Neonatal Hearing Screening Project. Otoacoustic emissions were recorded prior to discharge from maternity units, using IL088 equipment. We assessed the pass/fail rate using the Wessex criteria and 10 other pass/fail criteria published in the literature. Using Pearson’s correlation coefficient, a statistically significant correlation between signal-to-noise ratio at each of the frequency bands 1, 2, 3, 4 and 5 kHz and babies’ age in hours at the 0.01 level was identified. The correlation was also significant (0.01 level) between age and frequency reproducibility in each of the bands at 1, 2, 3, 4 and 5 kHz as well as the whole reproducibility. The number of false alarms reduced significantly after the first 24 h of life with all the criteria examined. We conclude that in the first hours after birth due to insufficient maturation of the otoacoustic emission, there is a high rate of false alarms. This increase in the false alarm rate, whilst dependent on the criteria used, occurs with all criteria. This leads to the consideration of whether the establishment of age-dependent pass/fail criteria could reduce the false alarm rate and the subsequent strain on diagnostic centres.
Effects of Hearing Aid Amplification and Stimulus Intensity on Cortical Auditory Evoked Potentials
Authors: Billings Curtis J. , Tremblay Kelly L. , Souza Pamela E. , Binns Malcolm A.
Published: March 2007

Hearing aid amplification can be used as a model for studying the effects of auditory stimulation on the central auditory system (CAS). We examined the effects of stimulus presentation level on the physiological detection of sound in unaided and aided conditions. P1, N1, P2, and N2 cortical evoked potentials were recorded in sound field from 13 normal-hearing young adults in response to a 1000-Hz tone presented at seven stimulus intensity levels. As expected, peak amplitudes increased and peak latencies decreased with increasing intensity for unaided and aided conditions. However, there was no significant effect of amplification on latencies or amplitudes. Taken together, these results demonstrate that 20 dB of hearing aid gain affects neural responses differently than 20 dB of stimulus intensity change. Hearing aid signal processing is discussed as a possible contributor to these results. This study demonstrates (1) the importance of controlling for stimulus intensity when evoking responses in aided conditions, and (2) the need to better understand the interaction between the hearing aid and the CAS.
Age-Related Changes in Vestibular Evoked Myogenic Potentials
Authors: Brantberg Krister , Granath Kerstin , Schart Nadine
Published: March 2007

Vestibular evoked myogenic potentials (VEMP) in response to sound stimulation (500 Hz tone burst, 129 dB SPL) were studied in 1000 consecutive patients. VEMP from the ear with the larger amplitude were evaluated based on the assumption that the majority of the tested patients probably had normal vestibular function in that ear. Patients with known bilateral conductive hearing loss, with known bilateral vestibular disease and those with Tullio phenomenon were not included in the evaluation. It was found that there was an age-related decrease in VEMP amplitude and an increase in VEMP latency that appeared to be rather constant throughout the whole age span. The VEMP data were also compared to an additional group of 10 patients with Tullio phenomenon. Although these 10 patients did have rather large VEMP, equally large VEMP amplitudes were observed in a proportion of unaffected subjects of a similar age group. Thus, the finding of a large VEMP amplitude in response to a high-intensity sound stimulation is not, per se, distinctive for a significant vestibular hypersensitivity to sounds.
Differential Cross-Sectional and Longitudinal Impact of APOE Genotype on Hippocampal Volumes in Nondemented Older Adults
Authors: Jak Amy J. , Houston Wes S. , Nagel Bonnie J. , Corey-Bloom Jody , Bondi Mark W.
Published: March 2007

Background/Aims: Because of conflicting findings across studies, we sought to better determine the relationship between apolipoprotein E (APOE) genotype, hippocampal volume, and cognitive performance in nondemented older adults. Methods: Two groups ofolder adults, as determined by their APOE Ε4 allele status, received structural MRI and comprehensive neuropsychological testing on two occasions separated on average by 17 months. Results: Cross-sectional comparisons by APOE group revealed no differences in hippocampal volumes, although longitudinal percent reduction in hippocampal volume was significantly greater for those possessing the APOE Ε4 allele. Relationship between hippocampal volumes and memory performance was strongly impacted by diagnosis of mild cognitive impairment. Conclusions: APOE Ε4 allele appears to significantly impact rate of volume loss over time in the hippocampus in nondemented older adults, and detailed cognitive characterization of the sample is necessary to reliably interpret the relationship between cognition and brain structure.
Electron-Beam Computerized Tomography Correlates with Coronary Angiogram in Chronic Kidney Disease Patients
Authors: Robinson Janelle , Tan Ainah U. , Wilensky Robert L. , Matthai William , Munoz Maura , Rosas Sylvia E.
Published: March 2007

Background/Aim: Electron-beam computerized tomography (EBCT) is able to noninvasively quantify coronary artery calcification (CAC). Chronic kidney disease (CKD) patients frequently have CAC, and clinicians are puzzled regarding the clinical significance of this finding and the diagnostic accuracy of coronary EBCT in CKD. The aim of this study was to determine the correlation in CKD patients between CAC measured by EBCT and 50% stenosis determined by coronary angiography (CA), the gold standard to identify atherosclerotic lesions. Method: We recruited 37 patients with CKD from a single institution and compared their coronary EBCT and CA results using standard statistical analysis. Results: Patients with at least one vessel with ≧50% stenosis by CA had higher mean CAC scores [2,407.9 ± (SD) 3,165.3 vs. 227 ± 443.4; p < 0.001] and higher median CAC scores (1,052 vs. 25.8; p < 0.001) as compared with those having no stenosis ≧50%. The sensitivity was 85.7%, and the specificity 82.6% using 50% stenosis as the definition for coronary artery disease and using a CAC score of 400 as a cutoff value for the EBCT results. The area under the receiver operating characteristic curve was 0.84. The diagnostic accuracy (proportion of correct results) was 83.8%. The negative predictive value was 90.5%. The receiver operating characteristic curve suggests that the optimal cutoff value for CAC scores in our cohort is 315.9, increasing the area under the receiver operating characteristic curve to 0.91. The total coronary artery stenosis was significantly associated with the CAC score (p = 0.01). Conclusions: EBCT has a very good predictive value for obstructive coronary artery disease. EBCT could be used as a screening tool in CKD patients with a low-to-intermediate risk for coronary artery disease.
Do Glucose and Lipids Exert Independent Effects on Atherosclerotic Lesion Initiation or Progression to Advanced Plaques?
Authors: Kanter Jenny E. , Johansson Fredrik , LeBoeuf Renee C. , Bornfeldt Karin E.
Published: March 2007

It is becoming increasingly clear that suboptimal blood glucose control results in adverse effects on large blood vessels, thereby accelerating atherosclerosis and cardiovascular disease, manifested as myocardial infarction, stroke, and peripheral vascular disease. Cardiovascular disease is accelerated by both type 1 and type 2 diabetes. In type 1 diabetes, hyperglycemia generally occurs in the absence of elevated blood lipid levels, whereas type 2 diabetes is frequently associated with dyslipidemia. In this review article, we discuss hyperglycemia versus hyperlipidemia as culprits in diabetes-accelerated atherosclerosis and cardiovascular disease, with emphasis on studies in mouse models and isolated vascular cells. Recent studies on LDL receptor–deficient mice that are hyperglycemic, but exhibit no marked dyslipidemia compared with nondiabetic controls, show that diabetes in the absence of diabetes-induced hyperlipidemia is associated with an accelerated formation of atherosclerotic lesions, similar to what is seen in fat-fed nondiabetic mice. These effects of diabetes are masked in severely dyslipidemic mice, suggesting that the effects of glucose and lipids on lesion initiation might be mediated by similar mechanisms. Recent evidence from isolated endothelial cells demonstrates that glucose and lipids can induce endothelial dysfunction through similar intracellular mechanisms. Analogous effects of glucose and lipids are also seen in macrophages. Furthermore, glucose exerts many of its cellular effects through lipid mediators. We propose that diabetes without associated dyslipidemia accelerates atherosclerosis by mechanisms that can also be activated by hyperlipidemia.
Endothelial Cell Migration During Angiogenesis
Authors: Lamalice Laurent , Le Boeuf Fabrice , Huot Jacques
Published: March 2007

Endothelial cell migration is essential to angiogenesis. This motile process is directionally regulated by chemotactic, haptotactic, and mechanotactic stimuli and further involves degradation of the extracellular matrix to enable progression of the migrating cells. It requires the activation of several signaling pathways that converge on cytoskeletal remodeling. Then, it follows a series of events in which the endothelial cells extend, contract, and throw their rear toward the front and progress forward. The aim of this review is to give an integrative view of the signaling mechanisms that govern endothelial cell migration in the context of angiogenesis.
What European Union Strategy for Integrating Migrants? The Role of OMC Soft Mechanisms in the Development of an EU Immigration Policy
Authors: Velluti Samantha
Published: March 2007

The paper maintains that OMC mechanisms, if adequately designed and used, as policy instruments which combine the use of soft and hard law at all levels of decision-making, could help promote the adoption of a human rights model in immigration policies and foster the protection and strengthening of TCNs human rights. In particular, OMC mechanisms could help revisit the philosophy underpinning EU immigration policy and foster a process which entails a shift from a central focus on securitization of immigration towards a more inclusive and proactive immigration policy and, consequently, provide the basis for a more coherent EU framework.
'She Came to Test Him with Hard Questions': Foreign Women and their View on Israel
Authors: Gillmayr-Bucher Susanne
Published: March 2007

Focusing on two foreign women, the queen of Sheba (1 Kings 10) and Rahab the prostitute (Joshua 2), this article shows how their otherness is shaped and used as a literary tool. Both women are introduced as strangers, but simultaneously they are portrayed with characteristic traits of good Israelites. The multifarious literary image of these women are used as a mirror for Israel. Hence inside and outside, self and other, and also superiority and inferiority are intermingled. Whereas the women themselves vanish from the stories, the interwoven aspects of their literary otherness cast a new light on Israel and its self-perception.
Contagion in Theology and Law: Ethical Considerations in the Writings of Two 14th Century Scholars of Nasrid Granada
Authors: Stearns Justin
Published: March 2007

The Black Death, which struck al-Andalus in the second half of the 8th/14th century, was an unprecedented natural disaster. In this essay I examine the legal and ethical responses of two Granadan scholars to the social and intellectual challenge posed by this event. Whereas previous scholarship has almost universally lauded the stridently critical stance of the wazir Ibn al-Khatīb as an exceptional example of rational empiricism, I argue that his stance is more productively understood when compared to that of his teacher Ibn Lubb. Both scholars articulated an ethical response to an insurmountable challenge from within a medical and legal framework. Their interpretive choices and conclusions were based not so much on one scholar's privileging of empirical evidence over legal dogma, or vice versa, as they were on both scholars' grounding their respective statements in differing understandings of the nature of the evidence at hand.
Ties of Labour and Ties of Commerce: Corvée among Seoul Merchants in the Late 19th Century
Authors: Miller Owen
Published: March 2007

The wealthiest guilds of the Choson Dynasty (1392-1910) capital, Seoul, formed part of the government's provisioning system, providing mainly luxury goods for royal palaces, government offices and tribute gifts to China and Japan. The guild merchants were also expected to provide corvée labour to the government on a regular basis, although by the late nineteenth century much of this labour was commuted to cash payments. Using a collection of surviving documents from the guildhall of the Myonjujon (Guild of Domestic Silk Merchants), this paper looks in detail at the burden of corvée labour, particularly during the politically and economically tumultuous years between 1884 and 1894. It finds that the merchants' corvée reflected the close relationship between guilds and government and also the two-sided nature of this relationship for the merchants. Thus, while they received certain protections and privileges from the government, the guild merchants were also particularly vulnerable to official corruption, which found a damaging outlet in the corvée system. Les guildes les plus riches de la dynastie de Chosaon (1392-1910) Séoul ont fait partie du système de l'approvisionnement du gouvernement, fournissant principalement des marchandises de luxe pour les palais royaux, les bureaux du gouvernement et les cadeaux d'hommage pour la Chine et le Japon. Les guildes était aussi obligés à fournir au gouvernement la corvée régulière, bien que par la fin du dix-neuvième siècle beaucoup de ce travail ait été commuté aux paiements en espèces. En utilisant une collection de documents extant dansla maison de la guilde des marchands en soie domestiques (Myaonjujaon), cet article regarde en détail le fardeau de la corvée, en particulier pendant des années tumultueuses, politiquement et économiquement, entre 1884 et 1894. Il constate que la corvée des marchands reflétait la relation étroite entre les guildes et le gouvernement et également le caractère double de cette relation pour les marchands. Ainsi, alors qu'ils recevaient de certains protections et privilèges du gouvernement, les marchands de guilde étaient particulièrement vulnérables à la corruption officielle qui menait à l'abus du système de la corvée.
Modification of the Atmospheric Boundary Layer by a Small Island: Observations from Nauru
Authors: Matthews Stuart , Hacker Jörg M. , Cole Jason , Hare Jeffrey , Long Charles N. , Reynolds R. Michael
Published: March 2007

Nauru, a small island in the tropical Pacific, generates cloud plumes that may grow to over 100-km lengths. This study uses observations to examine the mesoscale disturbance of the marine atmospheric boundary layer by the island that produces these cloud plumes. Observations of the surface layer were made from two ships in the vicinity of Nauru and from instruments on the island. The structure of the atmospheric boundary layer over the island was investigated using aircraft flights. Cloud production over Nauru was examined using remote sensing instruments. The diurnal cycles of surface meteorology and radiation are characterized at a point near the west (downwind) coast of Nauru. The spatial variation of surface meteorology and radiation are also examined using surface and aircraft measurements. During the day, the island surface layer is warmer than the marine surface layer and wind speed is lower than over the ocean. Surface heating forces the growth of a thermal internal boundary layer, within which a plume of cumulus clouds forms. Cloud production begins early in the morning over the ocean near the island’s lee shore; as heating intensifies during the day, cloud production moves upwind over Nauru. These clouds form a plume that may extend over 100 km downwind of Nauru. Aircraft observations showed that a plume of warm, dry air develops over the island that extends 15–20 km downwind before dissipating. Limited observations suggest that the cloud plume may be sustained farther downwind of Nauru by a pair of convective rolls. Suggestions for further investigation of the cloud plume are made.
Observations of Vertical Wind Shear Heterogeneity in Convective Boundary Layers
Authors: Markowski Paul , Richardson Yvette
Published: March 2007

Dual-Doppler wind syntheses from mobile radar observations obtained during the International H2O Project document some of the spatial variability of vertical wind profiles in convective boundary layers. Much of the variability of popular forecasting parameters such as vertical wind shear magnitude and storm-relative helicity is thought to result from pressure and temperature gradients associated with mesoscale boundaries (e.g., drylines, outflow boundaries, fronts). These analyses also reveal substantial heterogeneity even in the absence of obvious mesoscale wind shifts—in regions many might have classified as “horizontally homogeneous” with respect to these parameters in the past. This heterogeneity is closely linked to kinematic perturbations associated with boundary layer convection. When a mean wind is present, the large spatial variability implies significant temporal variability in the vertical wind profiles observed at fixed locations, with the temporal variability increasing with mean wind speed. Significant differences also can arise between true hodographs and “pseudohodographs” obtained from rawinsondes that are advected horizontally as they ascend. Some possible implications of the observed heterogeneity with respect to forecasting and simulating convective storms also are discussed.
Rapamycin Prevents Thyroid Hormone-Induced Cardiac Hypertrophy
Authors: Kuzman James A. , O’Connell Timothy D. , Gerdes A. Martin
Published: March 2007

Thyroid hormones (THs) have many effects on the cardiovascular system including cardiac hypertrophy. Although THs induce cardiac hypertrophy, the mechanism through which they exert this effect is unknown. We previously found that THs activate signaling related to increased protein synthesis [mammalian target of rapamycin (mTOR) and p70 S6 kinase] in the heart. It is unknown whether this activation contributes to TH-induced hypertrophy or whether it is merely incidental. In this study, we used rapamycin to inhibit mTOR function in mice and neonatal cardiomyocyte cultures treated with THs to test whether mTOR/S6 kinase signaling is involved in TH-mediated cardiac hypertrophy. C57 mice were treated with T4 for 3 d, 1 wk, 2 wk, or 1 month with either placebo, T4 (50 μg/100 g body weight·d), rapamycin (200 μg/100 g body weight·d) or T4/rapamycin by sc slow-release pellets. At the end of the treatment period, hemodynamics and physical data were collected and hearts were frozen for Western blot analysis or myocytes were isolated. The effects of T3 and rapamycin were also investigated using neonatal cardiomyocytes. THs activated specific components of the AKT signaling pathway in vivo and in vitro. THs induced cardiac hypertrophy, which was completely inhibited by rapamycin. Our results suggest that TH-induced hypertrophy is mediated by AKT/mTOR/S6 kinase signaling, which is important in the regulation of protein synthesis, a hallmark of cardiac hypertrophy.
Oxidative Degradation of Organic Pollutants by Hydrogen Peroxide in the Presence of FePz(dtnCl2)4 under Visible Irradiation
Authors: Sun Jie , Sun Yuping , Deng Kejian , Hou Haobo , Wang Duoyuan
Published: March 2007

A novel photocatalyst of iron(II)–tetra(5,6-dichloro-1,4-dithin)porphyrazine (abbreviated as FePz(dtnCl2)4) has been found to exhibit high catalytic activity to activate hydrogen peroxide for oxidative degradation of organic pollutants under visible light irradiation (λ > 420 nm) and wide pH range, in which Rhodamine B(RhB) and 4-nitro benzoic acid (NBA) were efficiently degraded and mineralized, while degraded residues and active oxygen species were also identified.
Dehydration of Concentrated Acetic Acid Solutions by Pervaporation Using Novel MER Zeolite Membranes
Authors: Nagase Takako , Kiyozumi Yoshimichi , Hasegawa Yasuhisa , Inoue Tomoya , Ikeda Takuji , Mizukami Fujio
Published: March 2007

The dehydration for the 90 wt % acetic acid (AcOH) solution was successfully performed for the first time using novel merlinoite (MER) zeolite membranes. The water selectivity was greater than 8000 by the pervaporation (PV) method. The permeation flux at 40 °C was 0.1 kg m−2 h−1. Furthermore, the membranes were stable more than 100 h under acidic conditions of pH 3.4.
A Good Linear Relationship between the Logarithms of Formation Constants and the Stabilization Energies of α- and β-Cyclodextrin Complexes of Several Phenol and Benzoic Derivatives
Authors: Wang Hai Ming , Song Le Xin
Published: March 2007

Semiempirical PM3 calculations in vacuo were performed on the inclusion complexation of α- and β-cyclodextrin (CD) with several phenol and benzoic acid derivatives. Those inclusion complexes with a higher negative value of stabilization energy (ΔEs) in vacuo should lead to a larger positive value of formation constant (Kf) in aqueous solution. A proposed mathematical expression was firstly given to assess the negative linear relationship between log Kf and ΔEs.
Size exclusion chromatographic and UV-VIS absorption analyses of unbleached and bleached softwood kraft pulps using LiCl/1,3-dimethyl-2-imidazolidinone as a solvent
Authors: Yanagisawa Masahiro , Isogai Akira
Published: March 2007

Unbleached and bleached kraft pulps and holocellulose prepared from softwood were totally soluble in 8% LiCl/1,3-dimethyl-2-imidazolidinone (LiCl/DMI). The solutions were analyzed by size exclusion chromatography with photodiode array and multi-angle laser light scattering detection (SEC-PDA-MALLS). The mobile phase consisted of 1% LiCl/DMI. The degree of polymerization (DP) and DP distribution of the softwood kraft pulps were determined, as well as the DP distribution of residual lignins based on their UV-VIS absorption patterns. Changes in DP for kraft pulps after a conventional bleaching sequence were evaluated, and the residual lignins were analyzed in the same way. Approximately half of the residual lignin in unbleached and bleached kraft pulps was present in polysaccharide fractions with high DP, which represented approximately 90% of the total yield. Some characteristic differences in the UV-VIS absorption pattern were observed between kraft pulps bleached with oxygen and chlorine. DP, DP distribution of polysaccharides, and distribution of residual lignin were clearly different for unbleached kraft pulp, unbleached sulfite pulp, and holocellulose. An unbleached kraft pulp prepared from hardwood showed different properties to the corresponding softwood preparation. The UV-VIS absorption patterns due to residual lignins were also very characteristic for the various pulps and holocellulose.
Improved quantitative determination of benzalkonium chloride in treated wood by liquid chromatography
Authors: Miyauchi Teruhisa , Mori Mitsunori
Published: March 2007

Ammoniacal copper quaternary (ACQ) wood preservatives contain benzalkonium chloride (BAC) as the active ingredient. BACs in commercial ACQ products comprise mainly benzyldimethyldodecyl ammonium chloride (C12 homologue) and benzyldimethyltetradecyl ammonium chloride (C14 homologue). Previously, we developed solid-phase extraction (SPE) on Oasis MCX as a strong cation exchanger, followed by liquid chromatography with UV detection (LC-UV) for the quantitative determination of C12 and C14 homologues in treated wood. In this study, the previous method was modified. Samples were cleaned up before analysis, and a weak cation exchanger, Oasis WCX, was employed. C12 and C14 homologues were added to 500 mg of powdered wood samples of Japanese cedar (Cryptomeria japonica), Japanese larch (Larix leptolepis), Sakhalin fir (Abies sachalinensis), and Yezo spruce (Picea jezoensis) at levels of 10, 1, and 0.1 mg g-1 wood. Treated wood samples were then extracted with HCl/EtOH, and the extracts were filtered and subjected to SPE with Oasis MCX and Oasis WCX, followed by LC-UV analysis. Recovery rates ranging from 90% to 111% were achieved for SPE using both cation exchangers for active ingredient concentrations of 0.1–10 mg g-1.
Detection of β-1-4-galactan in compression wood of Sitka spruce [Picea sitchensis (Bong.) Carrière] by immunofluorescence
Authors: Altaner Clemens , Hapca Adrian I. , Knox J. Paul , Jarvis Michael C.
Published: March 2007

β-1-4-Galactan has been detected in Sitka spruce [Picea sitchensis (Bong.) Carrière] by an immunofluorescence procedure. The anti-β-1-4-galactan monoclonal antibody LM5 was found to bind to compression wood (CW) tissue as identified by cell morphology features. In cross-sections, year rings with very fine bands of galactan-containing tissue were found. Cells in these bands expressed no morphological CW features. This finding was interpreted to imply that β-1-4-galactan synthesis is one of the first physiological reactions of CW formation. In cases where the CW character was pronounced, galactan was exclusively located in the outer cell-wall layers and was absent from the majority of the inner S2 layer.
Dynamic behaviour of cork and cork-filled aluminium tubes: Numerical simulation and innovative applications
Authors: Gameiro Celina Pires , Cirne José , Miranda Victor , Pinho-da-Cruz Joaquim , Teixeira-Dias Filipe
Published: March 2007

Cork is a unique and complex natural cellular material with many industrial applications. The purpose of this paper is to explore a new application field for the use of micro-agglomerate cork as an energy-absorbing medium. A numerical study on the energy absorption capabilities of square and circular cork-filled aluminium tubes with a width or diameter of 80 mm, length of 300 mm and variable thickness was performed with the finite element method code LS-DYNA™. The tubes were impacted uniaxially at 10 and 15 m s-1. The same analysis was carried out on aluminium foam-filled tubes. The results demonstrate that cork filling leads to a considerable increase in the energy absorbed for both section geometries, and that tube thickness plays an important role in the deformation modes and energy absorption. The investigation revealed better results for aluminium foam-filled structures, but demonstrated that micro-agglomerate cork has high potential as an energy-absorbing medium in crash protection applications.
Material point method simulations of transverse fracture in wood with realistic morphologies
Authors: Nairn John A.
Published: March 2007

A new numerical method called the material point method (MPM) is well suited for modeling problems with complex geometries and with crack propagation in arbitrary directions. In this paper, these features of MPM were used to simulate transverse fracture in solid wood. The simulations were run on the scale of growth rings. The ease with which MPM handles complex geometries was helpful for modeling realistic morphologies of earlywood and latewood. Because MPM discretizes a body into material points, it was possible to go directly from a digital image of wood to a numerical model by assigning the location and properties of material points based on the intensity or color of pixels in an image. Because the description of cracks in MPM is meshless, it can handle a variety of crack propagation and direction criteria and can simulate complex crack paths that are a consequence of the morphology of the specimen. MPM simulations were run for cracks in the radial direction, the tangential direction, and at two angles to the radial direction. The specimens were loaded by axial displacement or by wedge opening. The MPM simulations fully included contact effects during wedge loading. Finally, the potential for coupling such simulations to new experiments as a tool for characterization of wood is discussed.
Engineering Nanostructures for Single‐Molecule Surface‐Enhanced Raman Spectroscopy
Authors: Moskovits Martin , Jeong Dae‐Hong , Livneh Tsachi , Wu Yiying , Stucky Galen D.
Published: March 2007

Surface‐enhanced Raman spectroscopy (SERS), an effect discovered in the 1970s and studied systematically in the 1980s, received a significant “second wind” with the report (primarily by Nie and by Kneipp) of enhancements large enough to allow the Raman spectrum of single molecules to be obtained. It is now understood that this occurs as a result of the extremely high electromagnetic fields that can exist at appropriately configured gaps and interstices between nanoparticles and other nanostructures composed of suitable materials (such as silver). With this insight one is now in a position to fabricate structures that will dependably and repeatably produce single‐molecule SERS. We describe three such strategies: using molecular linkers to self‐assemble silver clusters possessing the correct geometry; fabricating nanowire rafts in which the gaps between nanowires are “hot”; and structuring the interior of nanopores so as to produce finely‐architectured nanostructured arrays.
Surface‐Enhanced Raman Scattering on Silver Nanoparticles in Different Aggregation Stages
Authors: Kneipp Katrin , Kneipp Harald
Published: March 2007

Enhancement factors of surface‐enhanced Raman scattering (SERS) are compared for crystal violet attached to 15–60‐nm‐sized colloidal silver particles in various aggregation stages using 830 nm and 407 nm laser excitation. Enhancement factors on the order of 106–107 have been measured at 407 nm excitation for molecules adsorbed on spatially‐isolated silver spheres exhibiting strong, sharp, single‐sphere plasmon resonance at 395 nm. Extremely large SERS enhancement factors on the order of 1014 are obtained at near infrared excitation for molecules on clusters built from colloidal particles. The SERS enhancement factor is demonstrated to be independent of the size of the clusters. The increase of SERS enhancement factors by 7–8 orders of magnitude by the formation of aggregates, as well as the extremely small density of “hot sites” exhibiting this high level of enhancement, provide further strong arguments for the electromagnetic origin of the hot spots and for strongly enhanced local optical fields as a key effect in SERS at an extremely high enhancement level.
Feasts of Becoming: Imagining a Literacy Classroom Based on Dialogic Beliefs
Authors: Fecho Bob , Botzakis Stergios
Published: March 2007

Bakhtin's language theories give educators a view into how people develop and communicate with language through dialogue. These conceptions can be applied to teaching in a variety of positive ways.

The authors explore how teaching based on Bakhtinian concepts might function in the classroom, paying particular attention to the concepts of dialogue, heteroglossia, carnival, and hybridity. Although they do not provide a specific model, they refer to five pedagogical practices that might take place:

Raising questions and authoring responses by and among all participants

Embracing the importance of context and the non‐neutrality of language

Encouraging multiples perspectives

Flattening or creating disturbance within existing hierarchies

Agreeing that learning is under construction and evolving rather than reified and static

The authors argue that a dialogic classroom is one where language is central to a meaning‐making process that, in turn, informs us about language. By opening up dialogue within classroom contexts by reference to Bakhtinian theories, the authors see opportunities for increased student engagement, more voices within classrooms, and more invigorating academic activities.
Maximizing the Effectiveness of Reading Aloud
Authors: Lane Holly B. , Wright Tyran L.
Published: March 2007

Reading aloud makes important contributions to young children's literacy development, but some methods of reading aloud are much more beneficial than others. Researchers have investigated ways to make read‐aloud sessions more meaningful for children, and several methods have emerged as particularly effective. This article examines the role of reading aloud to children and suggests ways for both teachers and parents to maximize the effectiveness of read‐aloud sessions with children.
Early versus delayed endocrine therapy for prostate cancer
Authors: Schröder Fritz H
Published: March 2007

Endocrine treatment (ET) has in the past been shown to be beneficial in delaying clinical progression in all stages of prostate cancer, leading to an improvement of progression free survival in virtually all trials ever conducted. The first observations on this issue date back to the studies of the Veterans Administration Cooperative Urological Research Group in the 1960s. The period of time during which ET and the resulting side effects can be avoided is strongly dependent on the clinical stage of the disease. This treatment period is long in men who have minimal disease, such as a rising prostate-specific antigen after potentially curative management; however, it is considerably shorter in men who initially present with metastatic disease. In these situations, the potential benefit in quality of life, and avoidance of adverse events must be matched against the benefit in terms of gaining progression free time for the individual patient. This difficult task is supported by information supplied in this review. Locally advanced and regional (lymph node positive; stage T3N0-1M0Gx) disease is the domain of adjuvant ET. In this field, important progress has recently been made due to trials, which combine aggressive treatment of the primary tumor with adjuvant ET initiated at the same time. Therefore, in locally advanced and regional disease, radiotherapy or surgery combined with adjuvant ET must be considered state-of-the-art.
Pasireotide, a multiple somatostatin receptor subtypes ligand, reduces cell viability in non-functioning pituitary adenomas by inhibiting vascular endothelial growth factor secretion
Authors: Zatelli Maria Chiara , Piccin Daniela , Vignali Cristina , Tagliati Federico , Ambrosio Maria Rosaria , Bondanelli Marta , Cimino Vincenzo , Bianchi Antonio , Schmid Herbert A , Scanarini Massimo , Pontecorvi Alfredo , De Marinis Laura , Maira Giulio , Uberti Ettore C degli
Published: March 2007

Somatostatin (SRIF) analogs have been employed in medical therapy of non-functioning pituitary adenomas (NFA), with contrasting results. Previous evidence showed that SRIF can exert its antiproliferative effects by reducing vascular endothelial growth factor (VEGF) secretion and action, and that VEGF expression may be related to pituitary tumor growth. The aim of our study was to clarify the possible effects of a multireceptor SRIF ligand on VEGF secretion and cell proliferation in human NFA primary cultures. We assessed the expression of SRIF receptors (SSTR1–5), the in vitro effects on VEGF secretion, and on cell viability of SRIF and of the stable SRIF analog pasireotide (SOM230), which activates SSTR1, 2, 3, and 5. Twenty-five NFA were examined by RT-PCR for expression of α-subunit, SSTR, VEGF, and VEGF receptors 1 (VEGF-R1) and 2 (VEGF-R2). Primary cultures were tested with SRIF and with pasireotide. All NFA samples expressed α-sub, VEGF and VEGFR-1 and 2, while SSTR expression pattern was highly variable. Two different groups were identified according to VEGF secretion inhibition by SRIF. VEGF secretion and cell viability were reduced by SRIF and pasireotide in the ‘responder’ group, but not in the ‘non-responder’ group, including NFA expressing SSTR5. SRIF and pasireotide completely blocked forskolin-induced VEGF secretion. In addition, SRIF and pasireotide completely abrogated the promoting effects of VEGF on NFA cell viability. Our data demonstrate that pasireotide can inhibit NFA cell viability by inhibiting VEGF secretion, and suggest that the multireceptor-SSTR agonist pasireotide might be useful in medical therapy of selected NFA.