bluuebunny/crossref_metadata_2025 huggingface dataset:
Oscillations in the Olfactory Bulb Carry Information About Odorant History
Authors: Zochowski Michal R. , Cohen Lawrence B.
Published: June 2005

While odorant-evoked oscillations in the vertebrate olfactory bulb have been studied extensively, information about their possible cognitive role has been missing. Using voltage-sensitive dye imaging, we show that repeated odorant presentations with interstimulus intervals of 2–12 s had dramatic and diverse effects on the three oscillations that occur in the turtle olfactory bulb. Two of the oscillations are strikingly depressed in response to the second stimulation even of a new odorant was presented. The third oscillation is enhanced if the odorant is the same but suppressed if the odorant is new. The effects suggest that the oscillations carry information about odorant novelty and consistency.
Functional Heterogeneity Among Neurons in the Nucleus Retroambiguus With Lumbosacral Projections in Female Cats
Authors: Boers J. , Ford T. W. , Holstege G. , Kirkwood P. A.
Published: June 2005

Nucleus retroambiguus (NRA), in the caudal medulla, projects to all spinal levels. One physiological role is abdominal pressure control, evidenced by projections to intercostal and abdominal motoneurons from expiratory bulbospinal neurons (EBSNs) within NRA. The roles of NRA projections to the lumbosacral cord are less certain, although those to limb motoneurons may relate to mating behavior and those to Onuf's nucleus (ON) to maintaining continence. To clarify this we physiologically characterized NRA projections to the lumbosacral cord. Extracellular recordings were made in NRA under anesthesia and paralysis in estrus cats. Administered CO2gave a strong respiratory drive. Antidromic unit responses were recorded to stimulation of the contralateral ventrolateral funiculus of L6, L7, or sacral segments and to microstimulation in the region of semimembranosus motor nucleus or ON. All units were found at sites showing expiratory discharges. Units that showed collisions between antidromic and spontaneous spikes (all in late expiration) were identified as EBSNs. These were common from the ventrolateral funiculus (VLF) of L6(42.5%) or L7(32.9%), but rare from the sacral VLF or the motor nuclei. Antidromic latencies revealed a subthreshold respiratory drive in some non-EBSNs. This group had lower conduction velocities than the EBSNs. The remainder, with a negligible respiratory drive, had even lower conduction velocities. A new population of NRA neurons has thus been defined. They are not active even with a strong respiratory drive, but may provide most of the synaptic input from NRA to lower lumbar and sacral segments and could subserve functions related to mating behavior.
Heterogeneity of Voltage- and Chemosignal-Activated Response Profiles in Vomeronasal Sensory Neurons
Authors: Labra Antonieta , Brann Jessica H. , Fadool Debra A.
Published: June 2005

Liolaemus lizards were explored to ascertain whether they would make an amenable model to study single-cell electrophysiology of neurons in the vomeronasal organ (VNO). Despite a rich array of chemosensory-related behaviors chronicled for this genus, no anatomical or functional data exist for the VNO, the organ mediating these types of behaviors. Two Liolaemus species ( L. bellii and L. nigroviridis) were collected in Central Chile in the Farellones Mountains and transported to the United States. Lizards were subjected to hypothermia and then a lethal injection of sodium pentabarbitol prior to all experiments described in the following text. Retrograde dye perfusion combined with histological techniques demonstrated a compartmentalization of the proportionally large VNO from the main olfactory epithelium (MOE) in cryosections of L. bellii. SDS-PAGE analysis of the VNO of both species demonstrated the expression of three G protein subunits, namely, Gαo, Gαi2, and Gβ, and the absence of Gαolf, Gα11, and Gq, the latter of which are traditionally found in the MOE. Vomeronasal (VN) neurons were enzymatically isolated for whole cell voltage-clamp electrophysiology of single neurons. Both species demonstrated a tetrodotoxin (TTX)-sensitive, rapidly inactivating sodium current and a tetraethylammonium (TEA)-sensitive potassium current that had a transient and sustained component. VN neurons were classified into two types dependent on the ratio of sodium over sustained potassium current. VN neurons exhibited outward and inward chemosignal-evoked currents when stimulated with pheromone-containing secretions taken from the feces, skin, and precloacal pores. Fifty-nine percent of the neurons were responsive to at least one compound when presented with a battery of five different secretions. The breadth of responsiveness (H metric) demonstrated a heterogeneous population of tuning with a mean of 0.29.
Neuromuscular Adaptation During Skill Acquisition on a Two Degree-of-Freedom Target-Acquisition Task: Dynamic Movement
Authors: Shemmell Jonathan , Tresilian James R. , Riek Stephan , Barry Benjamin K. , Carson Richard G.
Published: June 2005

In this experiment, we examined the extent to which the spatiotemporal reorganization of muscle synergies mediates skill acquisition on a two degree-of-freedom (df) target-acquisition task. Eight participants completed five practice sessions on consecutive days. During each session they practiced movements to eight target positions presented by a visual display. The movements required combinations of flexion/extension and pronation/supination of the elbow joint complex. During practice sessions, eight targets displaced 5.4 cm from the start position (representing joint excursions of 54°) were presented 16 times. During pre- and posttests, participants acquired the targets at two distances (3.6 cm [36°] and 7.2 cm [72°]). EMG data were recorded from eight muscles contributing to the movements during the pre- and posttests. Most targets were acquired more rapidly after the practice period. Performance improvements were, in most target directions, accompanied by increases in the smoothness of the movement trajectories. When target acquisition required movement in both dfs, there were also practice-related decreases in the extent to which the trajectories deviated from a direct path to the target. The contribution of monofunctional muscles (those producing torque in a single df) increased with practice during movements in which they acted as agonists. The activity in bifunctional muscles (those contributing torque in both dfs) remained at pretest levels in most movements. The results suggest that performance gains were mediated primarily by changes in the spatial organization of muscles synergies. These changes were expressed most prominently in terms of the magnitude of activation of the monofunctional muscles.
Presynaptic Modulation of Synaptic Transmission by Pregnenolone Sulfate as Studied by Optical Recordings
Authors: Chen Ling , Sokabe Masahiro
Published: June 2005

The effects of pregnenolone sulfate (PREGS), a putative neurosteroid, on the transmission of perforant path–granule cell synapses were investigated with an optical recording technique in rat hippocampal slices stained with voltage-sensitive dyes. Application of PREGS to the bath solution resulted in an acute augmentation of EPSP in a dose-dependent manner. The PREGS effect was dependent on the extracellular Ca2+ concentration ([Ca2+]o), but independent of NMDA receptor activation. PREGS caused a decrease in paired-pulse facilitation, which implies that PREGS positively modulates presynaptic neurotransmitter releases. Firmer support for this mechanism was that PREGS augmented the synaptically induced glial depolarization (SIGD) that reflects the activity of electrogenic glutamate transporters in glial cells during the uptake of released glutamate. The selective α7nAChR antagonist α-BGT or MLA prevented the SIGD increase by PREGS. Furthermore DMXB, a selective α7nAChR agonist, mimicked the PREGS effect on SIGD and antagonized the effect of PREGS. The presynaptic effect of PREGS was partially attenuated by the L-type Ca2+ channel (VGCC) blocker nifedipine. Based on these findings, we proposed a novel mechanism underlying the facilitated synaptic transmission by PREGS: this neurosteroid sensitizes presynaptic α7nAChR that is followed by an activation of L-type VGCC to increase the presynaptic glutamate release.
Solution of Volterra‐type integro‐differential equations with ageneralized Lauricella confluent hypergeometric function in the kernels
Authors: Saxena R. K. , Kalla S. L.
Published: June 2005

The object of this paper is to solve a fractional integro‐differential equation involving a generalized Lauricella confluent hypergeometric function in several complex variables and the free term contains a continuous function f(τ). The method is based on certain properties of fractional calculus and the classical Laplace transform. A Cauchy‐type problem involving the Caputo fractional derivatives and a generalized Volterra integral equation are also considered. Several special cases are mentioned. A number of results given recently by various authors follow as particular cases of formulas established here.
On the generalized Roper‐Suffridge extension operator in Banach spaces
Authors: Liu Ming-Sheng , Zhu Yu-Can
Published: June 2005

The generalized Roper‐Suffridge extension operator in Banach spaces is introduced. We prove that this operator preserves the starlikeness on some domains in Banach spaces and does not preserve convexity in some cases. Furthermore, the growth theorem and covering theorem of the corresponding mappings are given. Some results of Roper and Suffridge and Graham et al. in ℂn are extended to Banach spaces.
Cobalancing numbers and cobalancers
Authors: Panda G. K. , Ray P. K.
Published: June 2005

Cobalancing numbers and cobalancers are defined and
introduced. Many properties of cobalancing numbers are explored.
A link between the Pythagorean triplets and the cobalancing
numbers is also established.
The integral equation methods for the perturbed Helmholtz eigenvalue problems
Authors: Khelifi Abdessatar
Published: June 2005

It is well known that the main difficulty in solving eigenvalue problems under shape deformation relates to the continuation of multiple eigenvalues of the unperturbed configuration. These
eigenvalues may evolve, under shape deformation, as separated, distinct eigenvalues. In this paper, we address the integral equation method in the evaluation of eigenfunctions and the corresponding eigenvalues of the two‐dimensional Laplacian operator under boundary variations of the domain. Using surface
potentials, we show that the eigenvalues are the characteristic values of meromorphic operator‐valued functions.
Optimal Tikhonov approximation for a sideways parabolic equation
Authors: Fu Chu-Li , Li Hong-Fang , Xiong Xiang-Tuan , Fu Peng
Published: June 2005

We consider an inverse heat conduction problem with convection term which appears in some applied subjects. This problem is ill posed in the sense that the solution (if it exists) does not depend
continuously on the data. A generalized Tikhonov regularization method for this problem is given, which realizes the best possible accuracy.
Commutants of the Pommiez operator
Authors: Dimovski Ivan H. , Hristov Valentin Z.
Published: June 2005

The Pommiez operator (Δf)(z) = (f(z) − f(0))/z is considered in the space ℋ(G) of the holomorphic functions in an arbitrary finite Runge domain G. A new proof of a representation formula of Linchuk of the commutant of Δ in ℋ(G) is given. The main result is a representation formula of
the commutant of the Pommiez operator in an arbitrary invariant
hyperplane of ℋ(G). It uses an explicit convolution
product for an arbitrary right inverse operator of Δ or of
a perturbation Δ − λI of it. A relation between these
two types of commutants is found.
Generalized (𝔉, b, ϕ, ρ, θ)‐univex n‐set functions and global parametric sufficient optimality conditions in minmax fractional subset programming
Authors: Zalmai G. J.
Published: June 2005

We first define a new class of generalized convex n‐set functions, called (𝔉, b, ϕ, ρ, θ)‐univex functions, and then establish a fairly large number of global parametric sufficient optimality conditions under a variety of generalized (𝔉, b, ϕ, ρ, θ)‐univexity assumptions for a discrete minmax fractional subset programming problem.
Canonical equivariant extensions using classical Hodge theory
Authors: Allday Christopher
Published: June 2005

Lin and Sjamaar have used symplectic Hodge theory to obtain canonical equivariant extensions for
Hamiltonian actions on closed symplectic manifolds that have the strong Lefschetz property. Here we
obtain canonical equivariant extensions much more generally by means of classical Hodge theory.
Stability in a ball‐partition problem
Authors: Vogel Thomas I.
Published: June 2005

Stability for a capillary problem with surfaces meeting along a singular curve is analyzed using
eigenvalue methods.
On horizontal and complete lifts from a manifold withfλ(7, 1)‐structure to its cotangent bundle
Authors: Das Lovejoy S. , Nivas Ram , Pathak Virendra Nath
Published: June 2005

The horizontal and complete lifts from a manifold Mn to its cotangent bundles were studied by Yano and Ishihara, Yano and Patterson, Nivas and Gupta,
Dambrowski, and many others. The purpose of this paper is to use
certain methods by which fλ(7, 1)‐structure in Mn can be extended to . In particular, we have studied horizontal and complete lifts of fλ(7, 1)‐structure from a manifold to its cotangent bundle.
Explicit geodesic flow‐invariant distributions using SL2(ℝ)‐representation ladders
Authors: Alvarez-Parrilla Alvaro
Published: June 2005

An explicit construction of a geodesic flow‐invariant distribution lying in the
discrete series of weight 2k isotopic component is found, using
techniques from representation theory of SL2(ℝ). It is found that the distribution represents an AC measure on the unit tangent bundle
of the hyperbolic plane minus an explicit singular set. Finally, via an averaging argument, a geodesic flow‐invariant distribution on a closed hyperbolic surface is obtained.
On the LP‐convergence for multidimensional arrays of random variables
Authors: Van Thanh Le
Published: June 2005

For a d‐dimensional array of random variables
such that is uniformly integrable
for some 0 < p < 2, the Lp‐convergence is established for the sums (1/|n|1/p) (∑j≺n(Xj − aj)), where aj = 0 if 0 < p < 1, and aj = EXj if 1 ≤ p < 2.
Generalizations of the standard Artin representation are unitary
Authors: Abdulrahim Mohammad N.
Published: June 2005

We consider the Magnus representation of the image of the braid group under the generalizations of the standard Artin representation discovered by M. Wada. We show that the images of the generators of the braid group under the Magnus representation are unitary relative to a Hermitian matrix. As a special case,
we get that the Burau representation is unitary, which was known and proved by C. C. Squier.
History of Surfactant up to 1980
Authors: Obladen Michael
Published: June 2005

Remarkable insight into disturbed lung mechanics of preterm infants was gained in the 18th and 19th century by the founders of obstetrics and neonatology who not only observed respiratory failure but also designed devices to treat it. Surfactant research followed a splendid and largely logical growth curve. Pathological changes in the immature lung were characterized in Germany by Virchow in 1854 and by Hochheim in 1903. The Swiss physiologist von Neergard fully understood surfactant function in 1929, but his paper was ignored for 25 years. The physical properties of surfactant were recognized in the early 1950s from research on warfare chemicals by Pattle in Britain and by Radford and Clements in the United States. The causal relationship of respiratory distress syndrome (RDS) and surfactant deficiency was established in the USA by Avery and Mead in 1959. The Australian obstetrician Liggins induced lung maturity with glucocorticoids in 1972, but his discovery was not fully believed for another 20 years. A century of basic research was rewarded when Fujiwara introduced surfactant substitution in Japan in 1980 for treatment and prevention of RDS.
Age-Dependent Change of Uric Acid Level in the Dermis Using Cutaneous Microdialysis
Authors: Lee Yong Suk , Yang Jeong Hoon , Choi Jung Chul , Eun Hee Chul
Published: June 2005

Background: We had proposed the usefulness of cutaneous microdialysis for the study of antioxidants in the skin. Objective: We designed a study analyzing the level of uric acid in the skin, one of the major antioxidants, for an age-dependent change. Methods: 16 healthy male volunteers were divided into two groups according to age. Eleven subjects were in their 3rd decade, under 30 years of age (young group) and the others were their 8th decade (old group), over 70 years of age. Dialysate samples were analyzed using high-performance liquid chromatography analysis. Results: In the young group the mean level of uric acid was 31.9 ± 16.1 µg/ml, while in old group it was 13.4 ± 5.2 µg/ml. Conclusion: This result demonstrated an in vivo state of antioxidant level in the human skin and the age-dependent difference was concordant with other in vitro or ex vivo studies; therefore, cutaneous microdialysis could be used in analysis and monitoring studies including human antioxidants and anti-aging.
Clinical Outcome of Salmon Calcitonin Nasal Spray Treatment in Postmenopausal Women after Total Hip Arthroplasty
Authors: Peichl P. , Griesmacher A. , Kumpan W. , Schedl R. , Prosquil E. , Bröll H.
Published: June 2005

Objective: The increasing rate of hip fractures is giving rise to a number of socio-economic problems for the aging community. In addition to being unable to resume their previous living habits, many patients fail to achieve full functional recovery after the fractures. Total hip arthroplasty (THA) is a successful operation for the majority of patients with all forms of hip fractures, being performed increasingly often throughout the world. Revision rates for THA range up to 20% per year. Aseptic loosening is the reason for 75% of the revisions. An additional problem post-THA is the rate of heterotopic soft tissue calcification after THA, resulting in severely impaired function, pain, and a reduced range of hip movement. Subjects: In an open study, 37 women who had undergone cementless THA after accidental hip fractures were treated twice daily with 200 IU of salmon calcitonin nasal spray for 12 months. Simultaneously the patients received one bag of 1,000 mg calcium plus 880 IU vitamin D daily throughout the treatment period of 1 year. A parallel group of 38 women with a similar clinical status in terms of hip fractures and cementless THA were treated with only one bag of 1,000 mg calcium plus 880 IU vitamin D daily through the treatment period. Results: The results of this 12-month clinical trial show that 200 IU of salmon calcitonin nasal spray per day significantly improves the clinical outcome of postmenopausal elderly women following THA. Treatment with a salmon calcitonin nasal spray significantly reduces bone turnover, loss of bone density, and pain. The functional status of the patients was improved and the risk of falling reduced by rehabilitation during the observation period of 12 months. Additionally, calcitonin promoted the repair of hip fractures and was associated with a significantly lesser rate of refractures as well as periprosthetic ossifications. Conclusion: The increasing revision rate for THA during the first year and the patient’s problem of resuming their previous living habits are the main foci of our study. Calcitonin nasal spray seems to cause few side effects. The additive treatment appears to improve the clinical outcome of THA in elderly postmenopausal women.
Forgetting Numbers in Old Age: Strategy and Learning Speed Matter
Authors: Derwinger Anna , Stigsdotter Neely Anna , MacDonald Stuart , Bäckman Lars
Published: June 2005

Background: Memory intervention research with older adults has primarily focused on immediate effects of training. Little is known about whether memory training can prevent forgetting of a learned material over time. Objective: The main purpose of this study was to investigate the effects of memory training on forgetting of numerical information in old age. In addition, the effect of speed of learning on forgetting rate was examined. Methods: Two training programs were employed contrasting a number-consonant mnemonic strategy with a self-generated strategy. A non-practice control group was also included. There were 20 participants in each group (age range = 60–83 years). Following completion of training, participants memorized six 4-digit numbers to perfection. Retention was tested after 30 min, 24 h, 7 weeks, and 8 months. Results: The three groups showed equal rates of forgetting across the first two follow-up assessments. A different picture emerged for the last two occasions, with the self-generated strategy group remembering more items relative to the two other groups. Moreover, participants reaching the criterion in few trials exhibited less forgetting than slow learners. Conclusions: These data indicate that self-generated strategy training may have advantages over learning a classical mnemonic for preventing long-term forgetting of numeric materials in old age.
Hair Shaft Abnormalities – Clues to Diagnosis and Treatment
Authors: Itin Peter H. , Fistarol Susanna K.
Published: June 2005

Hair dysplasias are congenital or acquired alterations which often involve the hair shaft. Hair shaft abnormalities are characterized by changes in color, density, length and structure. Hair shaft alterations often result from structural changes within the hair fibers and cuticles which may lead to brittle and uncombable hair. The hair of patients with hair shaft diseases feels dry and looks lusterless. Hair shaft diseases may occur as localized or generalized disorders. Genetic predisposition or exogenous factors produce and maintain hair shaft abnormalities. Hair shaft diseases are separated into those with and those without increased hair fragility. In general, optic microscopy and polarized light microscopy of hair shafts provide important clues to the diagnosis of isolated hair shaft abnormalities or complex syndromes. To establish an exact diagnosis of dysplastic hair shafts, a structured history and physical examination of the whole patient are needed which emphasizes other skin appendages such as the nails, sweat and sebaceous glands. Profound knowledge on hair biology and embryology is necessary to understand the different symptom complexes. Therapy of hair shaft disorders should focus on the cause. In addition, minimizing traumatic influences to hair shafts, such as drying hair with an electric dryer or permanent waves and dyes, is important. A short hairstyle is more suitable for patients with hair shaft disorders.
A DNA Sequence Polymorphism in the Endoglin Gene Is Not Associated with Intracranial Aneurysm or Aneurysmal Subarachnoid Hemorrhage
Authors: Peters David G. , Kassam Amin B. , Chang Yue-Fang
Published: June 2005

Background and Purpose: Endoglin is a member of the transforming growth factor β family of proteins and plays a central role in vascular growth and development. There have been conflicting reports that polymorphic variation in the endoglin gene is a risk factor for intracranial aneurysms (IAs). We sought to further investigate the intron 7 5′-TCCCCC-3′ endoglin polymorphism as a risk factor for IA and subarachnoid hemorrhage (SAH) in a population of patients from western Pennsylvania. Methods: We genotyped 98 IA patients and 191 unaffected controls for a length polymorphism in intron 7 using PCR-based methods. Results: The endoglin polymorphism was not associated with IA or the incidence of aneurysm rupture and SAH. No association was found when data were stratified by smoking and hypertension. Conclusion: These data, from a population recruited in western Pennsylvania, support recent findings in Japanese and German populations that, despite earlier observation to the contrary, endoglin is not associated with IA. Furthermore, our study extends previous observations by demonstrating no association between endoglin and either IA or SAH regardless of whether data were stratified for modifiable risk factors such as smoking and hypertension.
Efficacy of Telithromycin in Community-Acquired Pneumonia Caused by Pneumococci with Reduced Susceptibility to Penicillin and/or Erythromycin
Authors: van Rensburg D.J. , Fogarty C. , Kohno S. , Dunbar L. , Rangaraju M. , Nusrat R.
Published: June 2005

Background: The efficacy of oral telithromycin was assessed in patients with community-acquired pneumonia (CAP) caused by Streptococcus pneumoniae with reduced susceptibility to penicillin and/or erythromycin. Methods: Patients with CAP who had received telithromycin 800 mg once daily for 5 or 7–10 days (n = 2,289) in eight phase III clinical trials, or telithromycin 800 mg once daily for 7 days (n = 50) in a phase II study were included in this pooled analysis. Patients with S. pneumoniae as the cause of infection were identified, with particular focus on those infected with strains with reduced susceptibility to penicillin (intermediate, minimal inhibitory concentration (MIC) 0.12–1.0 mg/l; resistant, MIC ≧2.0 mg/l) and/or resistance to erythromycin (MIC ≧1.0 mg/l). Per-protocol clinical and bacteriological outcomes were assessed 7–14 days post-therapy in the phase III studies, and at 7–21 days post-therapy or at the end of therapy in the phase II study. Results: Of the 327 telithromycin-treated patients with S. pneumoniae infection, 61 (19%) were infected with strains with reduced susceptibility to penicillin and/or erythromycin. Clinical cure and bacterial eradication rates in these patients were 91.8% (56/61) and 93.4% (57/61), respectively. Corresponding clinical cure and bacterial eradication rates overall for all isolates of pneumococci were 94.5% (309/327) and 96.0% (314/327), respectively. All isolates with reduced susceptibility to penicillin and/or erythromycin were susceptible to telithromycin (MIC ≤1.0 mg/l). Conclusion: These results indicate that telithromycin is an effective oral antibacterial for the treatment of CAP caused by pneumococci with reduced susceptibility to penicillin and/or erythromycin.
Adipose Tissue Metabolism and CD11b Expression on Monocytes in Obese Hypertensives
Authors: Boschmann Michael , Engeli Stefan , Adams Frauke , Gorzelniak Kerstin , Franke Gabriele , Klaua Susanne , Kreuzberg Ursula , Luedtke Susanne , Kettritz Ralph , Sharma Arya M. , Luft Friedrich C. , Jordan Jens
Published: June 2005

At a given degree of adiposity, metabolic and cardiovascular risk varies markedly between individuals. Animal studies suggest that differentially expressed systemic activation of monocytes contributes to the obesity-associated risk variability. We tested the hypothesis that systemic monocyte activation is associated with changes in adipose tissue and skeletal muscle metabolism. In 17 obese hypertensive patients, we assessed CD11b expression on circulating monocytes, gene expression in adipose tissue biopsies, and obtained blood samples and adipose tissue and skeletal muscle microdialysis samples in the fasted state and during a glucose load. Patients were stratified into groups with higher and lower CD11b expression on monocytes. Expression of the macrophage marker CD68 was increased markedly in adipose tissue of subjects with higher CD11b expression. Although no differences in systemic insulin sensitivity were found between both groups, patients with higher peripheral CD11b expression showed a markedly augmented increase in dialysate glucose in adipose tissue during oral glucose tolerance testing and increased adipose tissue lipolysis as well. Our data demonstrate that human monocyte activation is associated with tissue-specific changes in glucose and lipid metabolism. These findings may be explained in part by monocyte/macrophage infiltration of adipose tissue, which appears to interfere with insulin responsiveness.
New Insights Into the Regulation of HDL Metabolism and Reverse Cholesterol Transport
Authors: Lewis Gary F. , Rader Daniel J.
Published: June 2005

The metabolism of high-density lipoproteins (HDL), which are inversely related to risk of atherosclerotic cardiovascular disease, involves a complex interplay of factors regulating HDL synthesis, intravascular remodeling, and catabolism. The individual lipid and apolipoprotein components of HDL are mostly assembled after secretion, are frequently exchanged with or transferred to other lipoproteins, are actively remodeled within the plasma compartment, and are often cleared separately from one another. HDL is believed to play a key role in the process of reverse cholesterol transport (RCT), in which it promotes the efflux of excess cholesterol from peripheral tissues and returns it to the liver for biliary excretion. This review will emphasize 3 major evolving themes regarding HDL metabolism and RCT. The first theme is that HDL is a universal plasma acceptor lipoprotein for cholesterol efflux from not only peripheral tissues but also hepatocytes, which are a major source of cholesterol efflux to HDL. Furthermore, although efflux of cholesterol from macrophages represents only a tiny fraction of overall cellular cholesterol efflux, it is the most important with regard to atherosclerosis, suggesting that it be specifically termed macrophage RCT. The second theme is the critical role that intravascular remodeling of HDL by lipid transfer factors, lipases, cell surface receptors, and non-HDL lipoproteins play in determining the ultimate metabolic fate of HDL and plasma HDL-c concentrations. The third theme is the growing appreciation that insulin resistance underlies the majority of cases of low HDL-c in humans and the mechanisms by which insulin resistance influences HDL metabolism. Progress in our understanding of HDL metabolism and macrophage reverse cholesterol transport will increase the likelihood of developing novel therapies to raise plasma HDL concentrations and promote macrophage RCT and in proving that these new therapeutic interventions prevent or cause regression of atherosclerosis in humans.
In Vivo and In Vitro Studies Support That a New Splicing Isoform of
OLR1
Gene Is Protective Against Acute Myocardial Infarction
Authors: Mango Ruggiero , Biocca Silvia , del Vecchio Francesca , Clementi Fabrizio , Sangiuolo Federica , Amati Francesca , Filareto Antonio , Grelli Sandro , Spitalieri Paola , Filesi Ilaria , Favalli Cartesio , Lauro Renato , Mehta Jawahar L. , Romeo Francesco , Novelli Giuseppe
Published: June 2005

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), encoded by the
OLR1
gene, is a scavenger receptor that plays a fundamental role in the pathogenesis of atherosclerosis. LOX-1 activation is associated with apoptosis of endothelial cells, smooth muscle cells (SMCs), and macrophages. This process is an important underlying mechanism that contributes to plaque instability and subsequent development of acute coronary syndromes. Independent association genetic studies have implicated
OLR1
gene variants in myocardial infarction (MI) susceptibility. Because single nucleotide polymorphisms (SNPs) linked to MI are located in intronic sequences of the gene, it remains unclear as to how they determine their biological effects. Using quantitative real-time PCR and minigene approach, we show that intronic SNPs, linked to MI, regulate the expression of a new functional splicing isoform of the
OLR1
gene, LOXIN, which lacks exon 5. Macrophages from subjects carrying the “non-risk” disease haplotype at
OLR1
gene have an increased expression of LOXIN at mRNA and protein level, which results in a significant reduction of apoptosis in response to oxLDL. Expression of LOXIN in different cell types results in loss of surface staining, indicating that truncation of the C-terminal portion of the protein has a profound effect on its cellular trafficking. Furthermore, the proapoptotic effect of LOX-1 receptor in cell culture is specifically rescued by the coexpression of LOXIN in a dose-dependent manner. The demonstration that increasing levels of LOXIN protect cells from LOX-1 induced apoptosis sets a groundwork for developing therapeutic approaches for prevention of plaque instability.
Intracranial Bleeding in Patients With Vertebrobasilar Dolichoectasia
Authors: Passero Stefano G. , Calchetti Benedetta , Bartalini Sabina
Published: June 2005

Background and Purpose—

Intracranial bleeding in patients with vertebrobasilar dolichoectasia (VBD) is considered uncommon, but there are no precise data to support this opinion. The purpose of this study was to examine the incidence and characteristics of intracranial hemorrhage in patients with VBD and to evaluate factors that may promote bleeding.

Methods—

We conducted a prospective study of 156 consecutive VDB patients followed-up for an average 9.35 years. The association of demographic, clinical, and imaging features with occurrence of intracranial bleeding was evaluated by multivariate analysis. Survival analysis was used to evaluate rates of incidence.

Results—

32 hemorrhagic strokes were observed in 28 patients either as a diagnostic event (n=10) or during follow-up (n=22). Of the 32 hemorrhagic events, 6 were subarachnoid hemorrhage and 26 intraparenchymal hemorrhage. Multivariate analysis found an association between intracranial bleeding and maximum diameter of the basilar artery (OR, 4.29;
P
=0.009), degree of lateral displacement of the basilar artery (OR, 4.53;
P
=0.004), hypertension (OR, 4.74;
P
=0.024), use of antiplatelet or anticoagulant agents (OR, 3.07;
P
=0.033), and female sex (OR 6.33;
P
=0.001). The cumulative proportion of survivors free of hemorrhagic stroke was 88.6 at 5 years and 84.4 at 10 years.

Conclusions—

Our study showed that intracranial bleeding in patients with VBD is not as uncommon as usually believed. Its occurrence is associated with the degree of ectasia and elongation of the basilar artery and may be favored by hypertension and use of antiplatelet or anticoagulant agents.
Historical Droughts in Central Mexico and Their Relation with El Niño
Authors: Mendoza Blanca , Jáuregui Ernesto , Diaz-Sandoval Rosa , García-Acosta Virginia , Velasco Victor , Cordero Guadalupe
Published: June 2005

A catalog containing an unprecedented amount of historical data in central Mexico, covering almost six centuries (1450–1900), is used. This is a catalog of agricultural disasters that includes events associated with hydrometeorological phenomena, or hazards, whose effects were mainly felt in the agricultural sector, such as droughts. An analysis of the historical series of droughts in central Mexico for the period of 1450–1900 is performed. Periods of frequent drought centered at the years 1483, 1533, 1571, 1601, 1650, 1691, 1730, 1783, 1818, and 1860 have been identified. In particular, droughts in Mexico City and northwest Mexico that were identified through poor tree-ring growth are included in the frequent drought periods obtained in this work. Moreover, it was found that droughts occurred in El Niño years mainly for events of very strong and strong strengths, at a significant level. Also, most droughts lasted for 1 or 2 yr. Last, by analyzing the periodicities of the drought time series it was found that those that are the most conspicuous are the quasi-bidecadal frequencies of 18.9 and 21 yr.
Climatology of Mountain Venting–Induced Elevated Moisture Layers in the Lee of the Alps
Authors: Henne Stephan , Furger Markus , Prévôt AndréS. H.
Published: June 2005

Elevated moisture layers in the lower free troposphere (2000–6000 m MSL) in the lee of the Alps were investigated. Specific humidity was analyzed within a Lagrangian concept for fair-weather days during a 12-yr period at the windward and the leeward sides of the Alps for the sounding sites of Payerne, Switzerland, and Milan, Italy. During daytime fair-weather conditions (different criteria), specific humidity increased significantly in air masses that advected from Payerne to Milan in a layer ranging from ∼2500 to 4000 m MSL. The maximum relative increase of specific humidity in this layer was ∼0.3, meaning that ∼30% of the air in this layer originated from the Alpine atmospheric boundary layer. On average, ∼30% of the mass of the Alpine boundary layer was vented to altitudes higher than 2500 m MSL per hour during the daytime. The total precipitable water within a layer reaching from 2500 to 3500 m MSL increased by ∼1.3 mm. Similar elevated layers were observed for different selection methods of fair-weather days, and climatologically for the whole of June, July, and August. Average observations of the relative increase and boundary layer export rate agree with results from the local case studies. Daytime thermally driven flow systems seem to be the main source of additional water vapor in the observed elevated layers over the Alps. Subsequently, horizontal advection toward flat terrain where the average ABL top was well below the elevated layer bottom results in the export of ABL air to the free troposphere (mountain venting). Mountain venting was enhanced in situations with larger global radiation, lower atmospheric stability, and additional moist convection as was detected by lightning activity.
Flow around a Complex Building: Experimental and Large-Eddy Simulation Comparisons
Authors: Calhoun Ronald , Gouveia Frank , Shinn Joseph , Chan Stevens , Stevens Dave , Lee Robert , Leone John
Published: June 2005

A field program to study atmospheric releases around a complex building was performed in the summers of 1999 and 2000. The focus of this paper is to compare field data with a large-eddy simulation (LES) code to assess the ability of the LES approach to yield additional insight into atmospheric release scenarios. In particular, transient aspects of the velocity and concentration signals are studied. The simulation utilized the finite-element method with a high-fidelity representation of the complex building. Trees were represented with a canopy term in the momentum equation. Inflow and outflow conditions were used. The upwind velocity was constructed from a logarithmic law fitted to velocities obtained on two levels from a tower equipped with a 2D sonic anemometer. A number of different kinds of comparisons of the transient velocity and concentration signals are presented—direct signal versus time, spectral, Reynolds stresses, turbulent kinetic energy signals, and autocorrelations. It is concluded that the LES approach does provide additional insight, but the authors argue that the proper use of LES should include consideration of cost and may require an increased connection to field sensors; that is, higher-resolution boundary and initial conditions need to be provided to realize the full potential of LES.
Interepochal Changes in Summer Precipitation in the Southeastern United States: Evidence of Possible Urban Effects near Atlanta, Georgia
Authors: Diem Jeremy E. , Mote Thomas L.
Published: June 2005

Through modification of the planetary boundary layer, urbanization has the potential to have a significant impact on precipitation totals locally. Using daily summer-season precipitation data at 30 stations from 1953 to 2002, this study explores the possibility of urban effects as causes of spatial anomalies in precipitation in a zone within 180 km of Atlanta, Georgia. The time period is divided into consecutive epochs (e.g., 1953–77 and 1978–2002), and interepochal differences in precipitation totals, heavy-precipitation days, cumulative heavy precipitation, and atmospheric conditions are explored. The southern stations experienced significant decreases in precipitation, whereas significant precipitation increases occurred at central/west-central stations. The most striking increases occurred at Norcross, Georgia, which is ∼30 km northeast of downtown Atlanta; Norcross had the third smallest number of heavy-precipitation days during 1953–77, but, during 1978–2002, it had the most heavy-precipitation days. Not only did the amount of urban land cover upwind of Norcross increase substantially from the earlier to the later epochs, but regionwide dewpoint temperatures also increased significantly. Therefore, it is suspected that the increased precipitation at Norcross was caused by urban effects, and these effects may have been enhanced by increased atmospheric humidity.
Variability of Drop Size Distributions: Noise and Noise Filtering in Disdrometric Data
Authors: Lee Gyu Won , Zawadzki Isztar
Published: June 2005

Disdrometric measurements are affected by the spurious variability due to drop sorting, small sampling volume, and instrumental noise. As a result, analysis methods that use least squares regression to derive rainfall rate–radar reflectivity (R–Z) relationships or studies of drop size distributions can lead to erroneous conclusions. This paper explores the importance of this variability and develops a new approach, referred to as the sequential intensity filtering technique (SIFT), that minimizes the effect of the spurious variability on disdrometric data. A simple correction for drop sorting in stratiform rain illustrates that it generates a significant amount of spurious variability and is prominent in small drops. SIFT filters out this spurious variability while maintaining the physical variability, as evidenced by stable R–Z relationships that are independent of averaging size and by a drastic decrease of the scatter in R–Z plots. The presence of scatter causes various regression methods to yield different best-fitted R–Z equations, depending on whether the errors on R or Z are minimized. The weighted total least squares (WTLS) solves this problem by taking into account errors in both R and Z and provides the appropriate coefficient and exponent of Z = aRb. For example, with a simple R versus Z least squares regression, there is an average fractional difference in a and b of Z = aRb of 17% and 14%, respectively, when compared with those derived using WTLS. With Z versus R regression, the average fractional difference in a and b is 19% and 12%, respectively. This uncertainty in the R–Z parameters may explain 40% of the “natural variability” claimed in the literature but becomes negligible after applying SIFT, regardless of the regression methods used.
Study of Planar Ice Crystal Orientations in Ice Clouds from Scanning Polarization Lidar Observations
Authors: Noel Vincent , Sassen Kenneth
Published: June 2005

This paper presents a study of the orientation of ice crystals in cirrus and midlevel clouds, based on the analysis of several cases of scanning polarization lidar observations. The maximum angle that crystals deviate from the horizontal plane is inferred at consecutive altitude levels by fitting angle-dependent measurements of the linear depolarization ratio and backscattered intensities to a theoretical model with a Gaussian distribution of tilt angles. The average deviation angle is linked to the angular variation of backscatter. A rare observation of so-called Parry-oriented columns is also given to highlight the different backscattering behavior with lidar angle. For planar crystals, two orientation modes are found that depend on cloud temperature. High-level cold (<∼−30°C) clouds show a maximum deviation angle of ∼1.0°, whereas for warmer (>∼−20°C) midlevel clouds this angle averages ∼2.0°. This difference is caused by variations in particle shape and fall attitude that depend on temperature, likely involving a transition from simple plates to more widely fluttering dendrites at the warmer temperatures. Polarization lidar scans are clearly uniquely suited for the study of ice crystal orientations in clouds.
Spatial and Temporal Structure of the Urban Heat Island in Seoul
Authors: Kim Yeon-Hee , Baik Jong-Jin
Published: June 2005

The spatial and temporal structure of the urban heat island in Seoul, Korea, is investigated using near-surface temperature data measured at 31 automatic weather stations (AWSs) in the Seoul metropolitan area for the 1-yr period from March 2001 to February 2002. The urban heat island in Seoul deviates considerably from an idealized, concentric heat island structure, mainly because of the location of the main commercial and industrial sectors and the local topography. Relatively warm regions extend in the east–west direction and relatively cold regions are located near the northern and southern mountains. Several warm cores are observed whose intensity, size, and location are found to vary seasonally and diurnally. Similar to previous studies, the urban heat island in Seoul is stronger in the nighttime than in the daytime and decreases with increasing wind speed and cloud cover, but it is least developed in summer. The average maximum urban heat island intensity is 2.2°C over the 1-yr period and it is 3.4°C at 0300 local standard time (LST) and 0.6°C at 1500 LST. The reversed urban heat island is occasionally observed in the afternoon, but its intensity is very weak. An empirical orthogonal function (EOF) analysis is performed to find the dominant modes of variability in the Seoul urban heat island. In the analysis using temperature data that are averaged for each hour of the 1-yr period, the first EOF explains 80.6% of the total variance and is a major diurnal mode. The second EOF, whose horizontal structure is positive in the eastern part of Seoul and is negative in the western part, explains 16.0% of the total variance. This mode is related to the land use type and the diurnal pattern of anthropogenic heat release. In the analysis using temperature data at 0300 LST, the leading four modes explain 72.4% of the total variance. The first EOF reflects that the weakest urban heat island intensity is in summer. It is found that the urban heat island in Seoul is stronger on weekdays than weekends.
AERMOD: A Dispersion Model for Industrial Source Applications. Part I: General Model Formulation and Boundary Layer Characterization
Authors: Cimorelli Alan J. , Perry Steven G. , Venkatram Akula , Weil Jeffrey C. , Paine Robert J. , Wilson Robert B. , Lee Russell F. , Peters Warren D. , Brode Roger W.
Published: June 2005

The formulation of the American Meteorological Society (AMS) and U.S. Environmental Protection Agency (EPA) Regulatory Model (AERMOD) Improvement Committee’s applied air dispersion model is described. This is the first of two articles describing the model and its performance. Part I includes AERMOD’s characterization of the boundary layer with computation of the Monin–Obukhov length, surface friction velocity, surface roughness length, sensible heat flux, convective scaling velocity, and both the shear- and convection-driven mixing heights. These parameters are used in conjunction with meteorological measurements to characterize the vertical structure of the wind, temperature, and turbulence. AERMOD’s method for considering both the vertical inhomogeneity of the meteorological characteristics and the influence of terrain are explained. The model’s concentration estimates are based on a steady-state plume approach with significant improvements over commonly applied regulatory dispersion models. Complex terrain influences are provided by combining a horizontal plume state and a terrain-following state. Dispersion algorithms are specified for convective and stable conditions, urban and rural areas, and in the influence of buildings and other structures. Part II goes on to describe the performance of AERMOD against 17 field study databases.