bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Manganese and Cobalt Doping on Chromium Deposition at Pt/YSZ Cathode Interfaces
Authors: Wang Kangli , Fergus Jeffrey
Published: December 2008

The performance of solid oxide fuel cells (SOFCs) can be degraded by chromium deposition, the amount and location of which can be affected by the compositions of the electrolyte and electrodes. Understanding compositional effects, especially at SOFC operating conditions, is important for the selection of materials that will minimize the impact of chromium deposition. In this study, the effect of YSZ doping on Cr deposition at a Pt-electrode/YSZ-electrolyte interface was investigated. Comparison between undoped and doped YSZ electrolyte surfaces after cathodic polarization for 25 hours in moist air at 800 ºC in the presence of chromia indicated that the presence of Mn or Co in the electrolyte significantly promotes Cr deposition at the electrode/electrolyte interface. The SEM micrographs of the Co-doped YSZ electrolyte surface after cathodic polarization for 10 to 45 hours clearly showed that with Co doping, deposition of Cr preferentially occurs at YSZ grain boundary.
Electrochemical Characterization of Planar Anode Supported SOFC with Strontium-Doped Lanthanum Cobalt Oxide Cathodes
Authors: Hjelm Johan , Soegaard Martin , Knibbe Ruth , Hagen Anke , Mogensen Mogens
Published: December 2008

The electrochemical performance of anode supported cells with screen-printed Sr-doped lanthanum cobalt oxide cathodes was studied using electrochemical impedance spectroscopy and polarization measurements. In order to obtain information on the resistance contribution from the cathode alone symmetrical cell measurements were carried out. Analysis of the symmetrical cell data in term of a distribution of relaxation times aided in the selection of an appropriate equivalent circuit for the cathode. Cell performance was dependent on the interdiffusion barrier layer and it was shown that the concentration polarization losses were strongly overlapped with the cathode losses, which complicates the deconvolution of the impedance spectra into individual process and / or electrode specific contributions.
Onsager Transport Coefficients of Mixed Ionic Electronic Conduction in CeO2-δ
Authors: Park Woo-Seok , Yang Inseok , Yoo Han-Ill
Published: December 2008

For the system of CeO2-d with oxygen vacancies and electrons as majority charge carriers, a flux of oxygen vacancy should be driven, in principle, not only directly by its own electrochemical potential gradient, but also indirectly by that of electrons, and vice versa for the flux of electrons. It has, however, been routinely presumed that the two types of carriers migrate independently of each other or Lie=0, whence the effective charge of oxygen vacancy is +2. We have been trying to measure experimentally all the Onsager L-coefficients on the system CeO2-d in its entire stability region. It has been found that the as-measured coefficient ratio, Lie/Lii takes a value in the range of 0.7 to 1.6 depending on nonstoichiometry(d). Therefore, the effective charge of oxygen vacancy is not fixed at 2+, but in the range of 1.3 to 0.4. We will report the interim results together with the experimental details.
Oxygen Permeation and Electrical Transport Properties of 70 vol. % Bi1.6Y0.4O3 and 30 vol. % Ag Composite
Authors: Kobayashi Kiyoshi , Nishimura Mutsuki , Yamaguchi Shu
Published: December 2008

Oxygen permeability and electrical conductivity of a composite material constituted of 70 volume% of Bi1.6Y0.4O3 and 30 volume% of Ag (70BYO) have been measured as functions of temperature and normalized oxygen partial pressure difference. Different conduction paths of oxide ions and electrons were found to be formed in the composite ceramics by the Bi1.6Y0.4O3 and metallic silver, respectively from the combined results of total conductivity and oxygen permeability. The oxygen permeation flux is limited by the migration of oxide ions in Bi1.6Y0.4O3 paths with the sample thickness. The effective oxide ion conductivity calculated from the oxygen permeation flux shows the same temperature dependence of the oxide ion conductivity of non-composite Bi1.6Y0.4O3, and the values of 70BYO are almost the same with those for 60 vol. % Bi1.6Y0.4O3 - 40 vol. % Ag composite, regardless of the difference in the volume fraction of the oxide ion conduction paths.
Model for Water Transport in a Polymer Electrolyte Fuel Cell after Shutdown
Authors: Khandelwal Manish , Mench Matthew M. , Lee Sungho , Son Youngjin
Published: December 2008

To mitigate potential freeze-damage, enhance durability and cold start performance of polymer electrolyte fuel cell (PEFC), residual water in the fuel cell components must be minimized. Ideally, we would like to achieve complete liquid removal with minimal parasitic losses. A transient two-phase mathematical model has been formulated to predict the water redistribution in the fuel cell components, after the PEFC shutdown. The novel feature of the model is inclusion of a directly measured thermo-osmosis relationship in the electrolyte membrane, and also the phase change related transport (heat-pipe effect) in the porous media. A preliminary scale analysis found that thermo-osmotic flux in the membrane is almost same order of magnitude of diffusion flux and the heat pipe effect can enhance the thermal transport out of the porous media by 200-300%. Ultimately, this model will be used as a tool to help understand and minimize the residual water saturation in the fuel cell components under different shutdown conditions.
Two PKC consensus sites on human acid-sensing ion channel 1b differentially regulate its function
Authors: Bashari Edlira , Qadri Yawar J. , Zhou Zhen-Hong , Kapoor Niren , Anderson Susan J. , Meltzer Robert H. , Fuller Catherine M. , Benos Dale J.
Published: December 2008

Human acid-sensing ion channel 1b (hASIC1b) is a H+-gated amiloride-sensitive cation channel. We have previously shown that glioma cells exhibit an amiloride-sensitive cation conductance. Amiloride and the ASIC1 blocker psalmotoxin-1 decrease the migration and proliferation of glioma cells. PKC also abolishes the amiloride-sensitive conductance of glioma cells and inhibits hASIC1b open probability in planar lipid bilayers. In addition, hASIC1b's COOH terminus has been shown to interact with protein interacting with C kinase (PICK)1, which targets PKC to the plasma membrane. Therefore, we tested the hypothesis that PKC regulation of hASIC1b at specific PKC consensus sites inhibits hASIC1b function. We mutated three consensus PKC phosphorylation sites (T26, S40, and S499) in hASIC1b to alanine, to prevent phosphorylation, and to glutamic acid or aspartic acid, to mimic phosphorylation. Our data suggest that S40 and S499 are critical sites mediating the modulation of hASIC1b by PKC. We expressed mutant hASIC1b constructs in Xenopus oocytes and measured acid-activated currents by two-electrode voltage clamp. T26A and T26E did not exhibit acid-activated currents. S40A was indistinguishable from wild type (WT), whereas S40E, S499A, and S499D currents were decreased. The PKC activators PMA and phorbol 12,13-dibutyrate inhibited WT hASIC1b and S499A, and PMA had no effect on S40A or on WT hASIC1b in oocytes pretreated with the PKC inhibitor chelerythrine. Chelerythrine inhibited WT hASIC1b and S40A but had no effect on S499A or S40A/S499A. PKC activators or the inhibitor did not affect the surface expression of WT hASIC1b. These data show that the two PKC consensus sites S40 and S499 differentially regulate hASIC1b and mediate the effects of PKC activation or PKC inhibition on hASIC1b. This will result in a deeper understanding of PKC regulation of this channel in glioma cells, information that may help in designing potentially beneficial therapies in their treatment.
Sphingosine-1-phosphate inhibits high glucose-mediated ERK1/2 action in endothelium through induction of MAP kinase phosphatase-3
Authors: Whetzel Angela M. , Bolick David T. , Hedrick Catherine C.
Published: December 2008

Endothelial activation is a key early event in vascular complications of Type 1 diabetes. The nonobese diabetic (NOD) mouse is a well-characterized model of Type 1 diabetes. We previously reported that Type 1 diabetic NOD mice have increased endothelial activation, with increased production of monocyte chemoattractant protein (MCP)-1 and IL-6, and a 30% increase of surface VCAM-1 expression leading to a fourfold increase in monocyte adhesion to the endothelium. Sphingosine-1-phosphate (S1P) prevents monocyte:endothelial interactions in these diabetic NOD mice. Incubation of diabetic NOD endothelial cells (EC) with S1P (100 nmol/l) reduced ERK1/2 phosphorylation by 90%, with no significant changes in total ERK1/2 protein. In the current study, we investigated the mechanism of S1P action on ERK1/2 to reduce activation of diabetic endothelium. S1P caused a significant threefold increase in mitogen-activated kinase phosphatase-3 (MKP-3) expression in EC. MKP-3 selectively regulates ERK1/2 activity through dephosphorylation. Incubation of diabetic NOD EC with S1P and the S1P1-selective agonist SEW2871 significantly increased expression of MKP-3 and reduced ERK1/2 phosphorylation, while incubation with the S1P1/S1P3 antagonist VPC23019 decreased the expression of MKP-3, both results supporting a role for S1P1 in MKP-3 regulation. To mimic the S1P-mediated induction of MKP-3 diabetic NOD EC, we overexpressed MKP-3 in human aortic endothelial cells (HAEC) cultured in elevated glucose (25 mmol/l). Overexpression of MKP-3 in glucose-cultured HAEC decreased ERK1/2 phosphorylation and resulted in decreased monocyte:endothelial interactions in a static monocyte adhesion assay. Finally, we used small interfering RNA to MKP-3 and observed increased monocyte adhesion. Moreover, S1P was unable to inhibit monocyte adhesion in the absence of MKP-3. Thus, one mechanism for the anti-inflammatory action of S1P in diabetic EC is inhibition of ERK1/2 phosphorylation through induction of MKP-3 expression via the S1P-S1P1 receptor axis.
Altered central TRPV4 expression and lipid raft association related to inappropriate vasopressin secretion in cirrhotic rats
Authors: Carreño Flávia Regina , Ji Lisa L. , Cunningham J. Thomas
Published: December 2008

Inappropriate vasopressin (AVP) release causes dilutional hyponatremia in many pathophysiological states such as cirrhosis. The central molecular mechanisms that mediate inappropriate AVP release are unknown. We tested the hypothesis that changes in the expression or trafficking of TRPV4 in the central nervous system may contribute to inappropriate AVP release in the bile duct ligation (BDL) model of cirrhosis in the rat. Four weeks after surgery, BDL rats demonstrated significantly increased plasma vasopressin and plasma renin activity (PRA), hypervolemia, and decreased plasma osmolality. These effects were blocked by providing BDL rats with 2% saline to drink for 15 days. TRPV4 protein expression was significantly increased in brain punches from BDL rats containing the supraoptic nucleus (SON) of the hypothalamus (100% ± 11 to 157% ± 4.8), and this effect was blocked in BDL rats given saline. Immunohistochemistry demonstrated a significant increase in TRPV4-positive cells and the percentage of AVP neurons that also were TRPV4-positive in the SON of BDL rats. In the hypothalamus of BDL rats, TRPV4 lipid raft association increased compared with sham (from 100% ± 2.1 to 326.1% ± 16). This effect was significantly attenuated in BDL rats given 2% saline to drink (174% ± 11). In the brain stem, TRPV4 lipid raft association was reduced by BDL and inversely related to plasma AVP and PRA. We speculate that changes in TRPV4 expression and compartmentalization within lipid rafts could contribute to a feed-forward mechanism related to AVP release in cirrhosis.
Differential Involvement of the Anterior Cingulate and Primary Sensorimotor Cortices in Sensory and Affective Functions of Pain
Authors: Kuo Chung-Chih , Chiou Ruei-Jen , Liang Keng-Chen , Yen Chen-Tung
Published: December 2008

The present study examined the role of neurons in different pain-related functions of the anterior cingulate cortex (ACC) and primary sensorimotor cortex (SmI) by assessing their abilities to code different levels of noxious heat and activity changes evoked by classical fear conditioning involving electric shocks. Multiple single-unit activity was recorded with microwires implanted in the SmI and ACC of each rat. In the first set of experiments, the middle segment of the tail in each rat was irradiated with laser-heat pulses of various intensities. Neuronal responses in both the SmI and ACC increased with the intensity of the laser heat, although there was a significantly higher percentage of intensity-related units in the SmI. Furthermore, the stimulus–response curve of SmI ensemble activity had a steeper slope than that of the ACC. In the second set of experiments, rats were trained and tested on a conditioned fear-potentiated startle task in which a light was paired with an electric shock and, later, the startle response was elicited by a burst of noise in the presence or absence of light. A higher percentage of ACC units changed their neuronal responses to the conditioned stimulus after the light–shock pairing and the average activity change was also significantly stronger. Our results suggest that SmI neurons are better at coding laser-heat intensity than ACC neurons, whereas more ACC neurons are involved in conditioned fear associated with an electric shock than SmI neurons. These data provide evidence for differential contributions of the SmI and ACC to sensory and affective dimensions of pain.
Force–EMG Changes During Sustained Contractions of a Human Upper Airway Muscle
Authors: Schmitt Kori , DelloRusso Christiana , Fregosi Ralph F.
Published: December 2008

Human upper airway and facial muscles support breathing, swallowing, speech, mastication, and facial expression, but their endurance performance in sustained contractions is poorly understood. The muscular fatigue typically associated with task failure during sustained contractions has both central and intramuscular causes, with the contribution of each believed to be task dependent. Previously we failed to show central fatigue in the nasal dilator muscles of subjects that performed intermittent maximal voluntary contractions (MVCs). Here we test the hypothesis that central mechanisms contribute to the fatigue of submaximal, sustained contractions in nasal dilator muscles. Nasal dilator muscle force and EMG activities were recorded in 11 subjects that performed submaximal contractions (20, 35, and 65% MVC) until force dropped to ≤90% of the target force for ≥3 s, which we defined as task failure. MVC and twitch forces (the latter obtained by applying supramaximal shocks to the facial nerve) were recorded before the trial and at several time points over the first 10 min of recovery. The time to task failure was inversely related to contraction intensity. MVC force was depressed by roughly 30% at task failure in all three trials, but recovered within 2 min. Twitch force fell by 30–44% depending on contraction intensity and remained depressed after 10 min of recovery, consistent with low-frequency fatigue. Average EMG activity increased with time, but never exceeded 75% of the maximal, pretrial level despite task failure. EMG mean power frequency declined by 20–25% in all trials, suggesting reduced action potential conduction velocity at task failure. In contrast, the maximal evoked potential did not change significantly in any of the tasks, indicating that the EMG deficit at task failure was due largely to mechanisms proximal to the neuromuscular junction. Additional experiments using the interpolated twitch technique suggest that subjects can produce about 92% of the maximal evocable force with this muscle, which is not a large enough deficit to explain the entire shortfall in the EMG at task failure. These data show that the nervous system fails to fully activate the nasal dilator muscles during sustained, submaximal contractions; putative mechanisms are discussed.
Analysis of MAP/PH(1), PH(2)/2 Queue with Bernoulli Vacations
Authors: Kumar B. Krishna , Rukmani R. , Thangaraj V.
Published: December 2008

We consider a
two‐heterogeneous‐server queueing system with
Bernoulli vacation in which customers arrive according to a Markovian arrival
process (MAP). Servers returning from vacation immediately take another vacation
if no customer is waiting. Using matrix‐geometric method, the steady‐state
probability of the number of customers in the system is investigated. Some important
performance measures are obtained. The waiting time distribution and
the mean waiting time are also discussed. Finally, some numerical illustrations
are provided.
A Multidisciplinary Investigation to Determine the Structure and Source of Dimeric Impurities in AMG 517 Drug Substance
Authors: Silva Elipe Maria Victoria , Tan Zhixin Jessica , Ronk Michael , Bostick Tracy
Published: December 2008

In the initial scale‐up batches of the experimental drug substance AMG 517, a pair of unexpected impurities was observed by HPLC. Analysis of data from initial LC‐MS experiments indicated the presence of two dimer‐like molecules. One impurity had an additional sulfur atom incorporated into its structure relative to the other impurity. Isolation of the impurities was performed, and further structural elucidation experiments were conducted with high‐resolution LC‐MS and 2D NMR. The dimeric structures were confirmed, with one of the impurities having an unexpected C‐S‐C linkage. Based on the synthetic route of AMG 517, it was unlikely that these impurities were generated during the last two steps of the process. Stress studies on the enriched impurities were carried out to further confirm the existence of the C‐S‐C linkage in the benzothiazole portion of AMG 517. Further investigation revealed that these two dimeric impurities originated from existing impurities in the AMG 517 starting material, N‐acetyl benzothiazole. The characterization of these two dimeric impurities allowed for better quality control of new batches of the N‐acetyl benzothiazole starting material. As a result, subsequent batches of AMG 517 contained no reportable levels of these two impurities
Karyotype evolution of giraffes (Giraffa camelopardalis) revealed by cross-species chromosome painting with Chinese muntjac (Muntiacus reevesi) and human (Homo sapiens) paints
Authors: Huang L. , Nesterenko A. , Nie W. , Wang J. , Su W. , Graphodatsky A.S. , Yang F.
Published: December 2008

Considering the giraffe (Giraffa camelopardalis, GCA, 2n = 30) as a primitive species, its comparative genomic data are critical for our understanding of the karyotype evolution of pecorans. Here, we have established genome-wide chromosomal homologies between giraffe, Chinese muntjac (Muntiacus reevesi, MRE, 2n = 46) and human (Homo sapiens, HSA, 2n = 46) with whole sets of chromosome-specific paints from Chinese muntjac and human, in addition to providing a high-resolution G-banding karyotype of giraffe. Chinese muntjac and human chromosome paints detected 32 and 45 autosomal homologs in the genome of giraffe, respectively. Our results suggest that it would require at least thirteen fissions, six fusions and three intrachromosomal rearrangements to ‘transform’ the 2n = 44 eutherian ancestral karyotype to the 2n = 58 pecoran ancestral karyotype. During giraffe evolution, some ancestral eutherian syntenies (i.e. association of HSA3/21, 4/8, 7/16, 14/15, 16/19 and two forms of 12/22) have been retained, while several derived syntenies (i.e. associations of human homologous segments 2/1, 2/9, 5/19, 4/12/22, 8/9, and 10/20) have been produced. The reduction of chromosome number in giraffe from the 2n = 58 pecoran ancestral karyotype could be primarily attributed to extensive Robertsonian translocations of ancestral chromosomal segments. More complex chromosomal rearrangements (including tandem fusion, centromere repositioning and pericentric inversion) have happened during the evolution of GCA2 and GCA8.
Magnetic Resonance Imaging of Hepatocellular Carcinoma Using Contrast Media
Authors: Kim Myeong-Jin , Choi Jin-Young , Chung Yong Eun , Choi Sun Young
Published: December 2008

Magnetic resonance imaging (MRI) has been widely used for evaluation of focal lesions associated with hepatic carcinogenesis including hepatocellular carcinoma (HCC). By providing better tissue contrast compared to ultrasonography and computed tomography, MRI is considered the most sensitive modality for diagnosis of HCC. Dynamic MRI using gadolinium-based extracellular fluid (ECF) agents is useful for detection of hypervascular tumors and lesion characterization but has limitations in the diagnosis of hypovascular HCCs and lesion characterization of nonhypervascular tumors. MRI using superparamagnetic iron oxide agents may be useful for detecting and characterizing lesions that were not seen on dynamic MRI using ECF agents, but finding well-differentiated HCC and differentiating it from a dysplastic nodule can be difficult in some cases. Hepatobiliary agents that can be used in both dynamic MRI and delayed hepatobiliary phase imaging have great potential for improving characterization of focal lesions associated with hepatic carcinogenesis. Further studies are necessary to determine their roles in evaluation and management of HCCs.
Response Evaluation of Transcatheter Arterial Chemoembolization in Hepatocellular Carcinomas: The Usefulness of Sonazoid-Enhanced Harmonic Sonography
Authors: Xia Yu , Kudo Masatoshi , Minami Yasunori , Hatanaka Kinuyo , Ueshima Kazuomi , Chung Hobyung , Hagiwara Satoru , Inoue Tatsuo , Ishikawa Emi , Kitai Satoshi , Takahashi Shunsuke , Tatsumi Chie , Ueda Taisuke , Hayaishi Sosuke , Maekawa Kiyoshi
Published: December 2008

Background: The purpose of this study was to investigate if Sonazoid-enhanced harmonic ultrasonography (US) could be used to evaluate the responses of hepatocellular carcinomas (HCCs) to treatment with transcatheter arterial chemoembolization (TACE). Patients and Methods: Forty-three HCCs that had been treated by TACE were evaluated by Sonazoid-enhanced harmonic US and dynamic computed tomography (CT) approximately 1 week after their treatment. The detection rates of residual tumor blood supply using the two modalities were compared. Two months after chemoembolization, 16 of the 43 HCCs, which had no additional local treatment, were followed up with dynamic CT. The results of contrast-enhanced harmonic US and dynamic CT 1 week after chemoembolization were analyzed and compared with follow-up dynamic CT results. Results: The detection rates of positive enhancement with Sonazoid-enhanced harmonic US and dynamic CT 1 week after TACE were 25 (58.1%) of 43 lesions and 17 (39.5%) of 43 lesions, respectively. Sonazoid-enhanced harmonic US was significantly more sensitive than dynamic CT in depicting the residual tumor blood supply to HCCs 1 week after TACE (p < 0.01; χ2 test). The Sonazoid-enhanced harmonic US results of the 16 lesions 1 week after chemoembolization were consistent with the follow-up results of dynamic CT 2 months after chemoembolization. Conclusions: Sonazoid-enhanced harmonic US appears to be a highly sensitive and accurate modality for evaluating responses of HCCs shortly after TACE.
Surgical Treatment of Hepatocellular Carcinoma: Comparison of Resection and Transplantation
Authors: Sugawara Yasuhiko , Kokudo Norihiro
Published: December 2008

The treatment of hepatocellular carcinoma (HCC) has progressed remarkably over the last years. In patients with good hepatic functional reserve, liver resection should be considered as the therapeutic modality for local control of primary HCC, including a large tumor, or multiple HCCs with vascular invasion. Anatomic resection involves systematic elimination of the main tumor and its minute metastases. In cases with poor hepatic functional reserve, however, liver transplantation may be a better therapeutic option depending on patient age and tumor-related factors. Patients with tumors satisfying the Milan criteria (or its extended criteria) are good candidates for liver transplantation. We analyzed the findings from 100 patients with HCC who underwent living donor liver transplantation. The overall survival at 3 and 5 years after liver transplantation was 79 and 78%, respectively, with a median follow-up of 45 months. The treatment algorithm, based on evidence accrued from published papers, is now available and is useful for determining the therapeutic choice based on the tumor- and liver function-related conditions.
Expression Pattern of Aquaporin 1 in the Middle Ear of the Guinea Pig with Secretory Otitis Media
Authors: Zhang Qian , Liu Changjian , Gao Xia , Hu Yingyan , Guo Wei , Sun Jianhe , Li Xingqi
Published: December 2008

Objective: To explore the pathological change of water homeostasis in the secretory otitis media (SOM) middle ear, we observed the expression and regulation of aquaporin 1 (AQP1) in the SOM middle ear cavity. Methods: Reverse transcriptase polymerase chain reaction (RT-PCR), Western blotting and immunohistochemical staining were used to detect AQP1 in the bullae of SOM models and normal animals. The expression patterns of AQP1 in the SOM group were compared with those in the normal animal group. Results: RT-PCR and immunoblot analyses revealed that mRNAs encoding AQP1 were expressed in the middle ear membrane of the guinea pigs of both groups; AQP1 was also detected as 28-kDa proteins in both groups. Immunohistochemical analysis showed that AQP1 was localized on capillary endothelial cells and fibroblasts in the lamina propria mucosae as well as on flat and cubical epithelial cells. Quantitative analysis of RT-PCR and Western blotting revealed that AQP1 expression was higher in the SOM group than in the control group. The cellular expression of AQP1 was somewhat altered in the SOM middle ear. Conclusions: Our study suggests that AQP1 in the middle ear cavity may play a vital role in the accumulation of the effusion. It might work on the vessel-caused hydrops in the middle ear cavity.
A Population-Based Study of the Association between Trypanosoma cruzi Infection and Cognitive Impairment in Old Age (The Bambuí Study)
Authors: Lima-Costa M. Fernanda , Castro-Costa Erico , Uchôa Elizabeth , Firmo Joselia , Ribeiro Antonio Luiz P. , Ferri Cleusa P. , Prince Martin
Published: December 2008

Background: Limited clinical data suggest that chronic Trypanosoma cruzi infection, which causes Chagas’ disease (ChD), is associated with cognitive impairment. This study investigated this association in a large population-based sample of older adults. Methods: Participants in this cross-sectional study comprised 1,449 persons aged ≥60 years from a Brazilian endemic area (Bambuí). Cognitive functioning was ascertained by the Mini-Mental State Examination (MMSE), considering its score in percentiles [≤14 (<5th percentile), 15–22 (5th to <25th) and ≥23]. Hypothesized risk factors were T. cruzi infection, ChD-related electrocardiographic (ECG) abnormalities and use of digoxin medication. Potential confounders included depressive symptoms, smoking, stroke, hemoglobin, HDL cholesterol, blood glucose, systolic blood pressure, and use of psychoactive medication. Results: The prevalence of T. cruzi infection was 37.6%. There was a graded and independent association between infection and the MMSE score (adjusted odds ratios estimated by ordinal logistic regression = 1.99; 95% CI 1.43–2.76). No significant associations between the MMSE score and ECG abnormalities or digoxin medication use were found. Conclusions: This study provides for the first time epidemiological evidence of an association between T. cruzi infection and cognitive impairment which was not mediated by either ChD-related ECG abnormalities or digoxin medication use.
Impact of Gene-Gender Effects of Adrenergic Polymorphisms on Hypothalamic-Pituitary-Adrenal Axis Activity in Depressed Patients
Authors: Haefner S. , Baghai T.C. , Schule C. , Eser D. , Spraul M. , Zill P. , Rupprecht R. , Bondy B.
Published: December 2008

Objective: There is overwhelming evidence that activation of the hypothalamic-pituitary-adrenal (HPA) system plays a major role in depression and cardiovascular disease in genetically susceptible individuals. We hypothesized that due to the multiple interactions between the sympathetic and the HPA systems via adrenoceptors, polymorphisms in these genes could have an impact on HPA axis activity in major depression. Methods: Using the dexamethasone/corticotrophin-releasing hormone (DEX/CRH) test, we investigated the association of α2-adrenoceptor (ADRA2A –1291C→G) and the β2-adrenoceptor gene (ADRB2 Arg16Gly) in 189 patients with major depression during the acute state of the disease and after remission. Results: Male ADRA2A –1291G allele homozygotes showed significant pretreatment HPA axis hyperactivity, with increased adrenocorticotropin (ACTH; F = 4.9, d.f. = 2, p = 0.009) and cortisol responses (F = 6.4, d.f. = 2, p = 0.003). In contrast, female ADRB2 Arg/Arg homozygotes had increased pretreatment ACTH (F = 7.17, d.f. = 2, p = 0.001) and cortisol (F = 8.95, d.f. = 2, p = 0.000) levels. Interestingly, in the respective genotypes, the stress hormones remained elevated in the second DEX/CRH test, despite a reduction in depressive symptoms. Conclusions: This study provides evidence that, depending on gender and polymorphisms, there is continuous HPA axis overdrive in a proportion of patients irrespective of the status of depression. Considering the importance of stress hormones for cardiovascular disorders, our data might suggest that these patients are at high risk of comorbidity between depression and cardiovascular disorders.
Meta-Analysis of the Brain-Derived Neurotrophic Factor Gene (BDNF) Val66Met Polymorphism in Anxiety Disorders and Anxiety-Related Personality Traits
Authors: Frustaci Alessandra , Pozzi Gino , Gianfagna Francesco , Manzoli Lamberto , Boccia Stefania
Published: December 2008

Objective: Brain-derived neurotrophic factor (BDNF) is potentially involved in the pathogenesis of anxiety. We carried out meta-analyses to evaluate the relationship between the BDNF Val66Met (valine, methionine) polymorphism and anxiety disorders (AD) or anxiety-related personality traits (ARPT). Methods: Medline, Embase and PsycINFO were searched up to December 2007. We investigated 3 outcomes related to BDNF Val66Met polymorphisms: (1) clinically diagnosed cases of AD; (2) ARPT in subjects without psychiatric diagnoses, assessed either by the Neuroticism scale of NEO-Personality Inventory forms (NEO-PI, NEO-PI-R, NEO-FFI), or by (3) the Harm Avoidance (HA) scale of Tridimensional Personality Questionnaire (TPQ) or its extended version Temperament and Character Inventory (TCI). Results: Seven case-control studies were selected for AD, including 1,092 cases and 8,394 controls, while 5 cross-sectional studies for Neuroticism (n = 1,633) and 4 for HA (n = 607). Both Met/Met and Val/Met individuals, as compared to Val/Val, showed a statistically significant lower Neuroticism score [SMD = –0.24 (95% CI: –0.44, –0.04), and –0.11 (95% CI: –0.22, –0.01), respectively]. No significant association was found between BDNF Val66Met polymorphism and AD [OR = 1.13 (95% CI: 0.85–1.52) for Met/Met versus Val/Val] or HA [SMD = 0.11 (95% CI: –0.19, 0.42) for Met/Met vs. Val/Val]. Conclusions: The low number of studies on this topic and their limited sample size, along with the inner limits in the definition of anxiety phenotypes, suggest caution in the interpretation of these results. Larger additional studies possibly investigating the interaction with other genes and environmental exposures are required to confirm these results.
Noncanalized Horns of Uterus Didelphys with Prolapse: A Unique Case in a Young Woman
Authors: Christopoulos P. , Deligeoroglou E. , Liapis A. , Agapitos E. , Papadias K. , Creatsas G.
Published: December 2008

The authors report the unique case of a 20-year-old patient with prolapsed uterus didelphys with noncanalized horns, who complained of primary amenorrhea. Clinical examination revealed a rudimentary noncanalized cervix with a third degree prolapse and no palpable uterus. A small prolapsing remnant of a uterus didelphys with 2 noncanalized uterine horns was excised by laparotomy. Ultrastructural examination of subepithelial cervical connective tissue revealed collagen of normal structure, but of low concentration. The etiologies of both the Müllerian ducts anomalies and the genital prolapse are probably multifactorial. Low collagen concentration indicates a constitutional tissue weakness contributing to the development of genital prolapse.
New Components of ‘Basal Laminar Deposits’ in Age-Related Macular Degeneration
Authors: Reale Enrico , Groos Stephanie , Eckardt Ute , Eckardt Claus , Luciano Liliana
Published: December 2008

Two new components of basal laminar deposit (BlamD) occurring in samples of submacular neovascular membranes surgically removed from patients with a wet (exudative) form of age-related macular degeneration are described. They are: (1) minute ribbon-like structures which occur singly and/or in a bunch and extend from the inner surface of the BlamD layer into the extracellular matrix (ECM) beneath the retinal pigment epithelium (RPE). The ribbons are composed of polarized molecules, aggregating in parallel, aligned transversally in register, morphologically similar to isolated collagen molecules of the short-chain type. Deeper in the BlamD but always close to its inner surface, aspects suggesting a transition between ribbons and (2) long-spacing collagen (LSC)-like aggregates characterized by periods bordered by a single dense band were observed. This band could arise from the globular domains of the polarized monomers, which assemble in parallel and display all their terminal extensions at the same end of each period resulting in the single dense band. The presence of ribbons and of LSC-like aggregates in the BlamD layer and the concomitant choroidal neovascularization (CNV) suggest that the events might be correlated. The newly formed vessels crossing Bruch’s membrane and invading the BlamD layer could induce physicochemical changes in the ECM of the RPE, providing the required environmental conditions for the polymerization of collagen molecules into aggregates with the LSC-like pattern. With the deposition of new components, the thickness of BlamD increases and further impairs the supply of nutrients and oxygen, thus sustaining CNV.
Osteogenic and Adipogenic Cell Fractions Isolated from Postnatal Mouse Calvaria
Authors: Steenhuis P. , Carr K.M. , Pettway G.J. , Ignelzi, Jr. M.A.
Published: December 2008

The use of stem/progenitor cells represents a promising approach to treat craniofacial bone defects, but successful treatments will rely on the availability of cells that can be expanded in vitroand which will differentiate appropriately in vivo. The calvaria may represent a source of autologous cells for such purposes. We demonstrate expression of stem cell antigen-1 (Sca-1) in mouse calvaria. We isolated Sca-1+ and Sca-1– cells at high purity and tested the ability of these cells to differentiate into adipose and bone. We show that the Sca-1+ cell fraction has adipogenic differentiation potential and that the cell Sca-1– fraction has osteogenic differentiation potential. The Sca-1+ cell fraction partially retains its adipogenic differentiation potential and the Sca-1– cell fraction partially retains its osteogenic differentiation potential after in vitroexpansion. These data suggest that the calvaria may be used as a source of stem/progenitor cells that can be expanded in vitroand transplanted in vivofor craniofacial tissue regeneration.
Route of Epoetin Administration Influences Hemoglobin Variability in Hemodialysis Patients
Authors: Patel Tejas , Hirter Angie , Kaufman James , Keithi-Reddy Sai Ram , Reda Domenic , Singh Ajay
Published: December 2008

Background: Compared to the intravenous route, subcutaneous administration of epoetin requires lower dose and will be an attractive option for cost containment when bundling for dialysis is implemented. Hemoglobin variability defined as fluctuation of hemoglobin over time has not been well studied with respect to the route of administration. Methods: 157 prevalent-hemodialysis subjects were analyzed from an open-label, randomized study that compared the intravenous to the subcutaneous route of epoetin with identical weight-based dosing algorithm. Hemoglobin variability was defined as the number of weeks hemoglobin is outside the target range of 10–11 g/dl. Sensitivity analysis was performed. Results: 78 subjects in the intravenous and 79 in the subcutaneous group entered the 24-week dose maintenance phase. Baseline covariates were similar in both groups except for the dose of epoetin (lower in subcutaneous) and dialysis vintage (longer in intravenous). Patients on subcutaneous epoetin were outside the target range more weeks (p = 0.04) and had higher standard deviation of hemoglobin (p = 0.01) compared to the intravenous group. Conclusions: The subcutaneous route of epoetin was associated with modestly higher hemoglobin variability, probably reflecting greater sensitivity of the subcutaneous route and/or identical epoetin-dosing algorithm employed in both the arms. This study could serve as an important guide when bundling for dialysis services is implemented as switching from intravenous to subcutaneous administration is likely to occur.
Lake-Effect Thunderstorms in the Lower Great Lakes
Authors: Steiger Scott M. , Hamilton Robert , Keeler Jason , Orville Richard E.
Published: December 2008

Cloud-to-ground (CG) lightning, radar, and radiosonde data were examined to determine how frequently lake-effect storms (rain/snow) with lightning occurred over and near the lower Great Lakes region (Lakes Erie and Ontario) from September 1995 through March 2007. On average, lake-effect lightning occurred on 7.9 days and with 5.8 storm events during a particular cool season (September–March). The CG lightning with these storms had little inland extent and was usually limited to a few flashes per storm. Some storms had considerably more, with the most intense storm (based on National Lightning Detection Network observations) producing 1551 CG flashes over a 4-day period. Thundersnow events were examined in more detail because of the rarity of this phenomenon across the United States. Most lake-effect thundersnow events (75%) occurred in November and December. An analysis of model sounding data using the Buffalo Toolkit for Lake Effect Snow (BUFKIT) software package in which lower boundary conditions can be modified by lake surfaces showed that thundersnow events had an 82% increase in the mean height of the −10°C level when compared with nonelectrified lake-effect snowstorms (1.2 vs 0.7 km AGL), had higher lake-induced equilibrium levels (EL; above 3.6 km AGL) and convective available potential energy (CAPE; >500 J kg−1), had low wind shear environments, and were intense, single-band storms. A nomogram of the altitude of the −10°C isotherm and EL proved to be useful in predicting lake-effect thundersnowstorms.
Simulation of a Serial Upstream-Propagating Mesoscale Convective System Event over Southeastern South America Using Composite Initial Conditions
Authors: Anabor Vagner , Stensrud David J. , de Moraes Osvaldo L. L.
Published: December 2008

Serial upstream-propagating mesoscale convective system (MCS) events over southeastern South America are important contributors to the local hydrologic cycle as they can provide roughly half of the total monthly summer precipitation. However, the mechanisms of upstream propagation for these events have not been explored. To remedy this situation, a numerical simulation of the composite environmental conditions from 10 observed serial MCS events is conducted. Results indicate that the 3-day simulation from the composite yields a reasonable evolution of the large-scale environment and produces a large region of organized convection in the warm sector over an extended period as seen in observations. Upstream propagation of the convective region is produced and is tied initially to the development and evolution of untrapped internal gravity waves. However, as convective downdrafts develop and begin to merge and form a surface cold pool in the simulation, the cold pool and its interaction with the environmental low-level flow also begins to play a role in convective evolution. While the internal gravity waves and cold pool interact over a several hour period to control the convective development, the cold pool eventually dominates and determines the propagation of the convective region by the end of the simulation. This upstream propagation of a South American convective region resembles the southward burst convective events described over the United States and highlights the complex interactions and feedbacks that challenge accurate forecasts of convective system evolution.
An Empirical Model for Surface Wind Stress Response to SST Forcing Induced by Tropical Instability Waves (TIWs) in the Eastern Equatorial Pacific
Authors: Zhang Rong-Hua , Busalacchi Antonio J.
Published: December 2008

High-resolution space-based observations reveal significant two-way air–sea interactions associated with tropical instability waves (TIWs); their roles in budgets of heat, salt, momentum, and biogeochemical fields in the tropical oceans have been recently demonstrated. However, dynamical model-based simulations of the atmospheric response to TIW-induced sea surface temperature (SSTTIW) perturbations remain a great challenge because of the limitation in spatial resolution and realistic representations of the related processes in the atmospheric planetary boundary layer (PBL) and their interactions with the overlying free troposphere. Using microwave remote sensing data, an empirical model is derived to depict wind stress perturbations induced by TIW-related SST forcing in the eastern tropical Pacific Ocean. Wind data are based on space–time blending of Quick Scatterometer (QuikSCAT) Direction Interval Retrieval with Thresholded Nudging (DIRTH) satellite observations and NCEP analysis fields; SST data are from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI). These daily data are first subject to a spatial filter of 12° moving average in the zonal direction to extract TIW-related wind stress (τTIW) and SSTTIW perturbations. A combined singular value decomposition (SVD) analysis is then applied to these zonal high-pass-filtered τTIW and SSTTIW fields. It is demonstrated that the SVD-based analysis technique can effectively extract TIW-induced covariability patterns in the atmosphere and ocean, acting as a filter by passing wind signals that are directly related with the SSTTIW forcing over the TIW active regions. As a result, the empirical model can well represent TIW-induced wind stress responses as revealed directly from satellite measurements (e.g., the structure and phase), but the amplitude can be underestimated significantly. Validation and sensitivity experiments are performed to illustrate the robustness of the empirical τTIW model. Further applications are discussed for taking into account the TIW-induced wind responses and feedback effects that are missing in large-scale climate models and atmospheric reanalysis data, as well as for uncoupled ocean and coupled mesoscale and large-scale air–sea modeling studies.
A Probabilistic Multimodel Ensemble Approach to Seasonal Prediction
Authors: Min Young-Mi , Kryjov Vladimir N. , Park Chung-Kyu
Published: December 2008

A probabilistic multimodel ensemble prediction system (PMME) has been developed to provide operational seasonal forecasts at the Asia–Pacific Economic Cooperation (APEC) Climate Center (APCC). This system is based on an uncalibrated multimodel ensemble, with model weights inversely proportional to the errors in forecast probability associated with the model sampling errors, and a parametric Gaussian fitting method for the estimate of tercile-based categorical probabilities.

It is shown that the suggested method is the most appropriate for use in an operational global prediction system that combines a large number of models, with individual model ensembles essentially differing in size and model weights in the forecast and hindcast datasets being inconsistent. Justification for the use of a Gaussian approximation of the precipitation probability distribution function for global forecasts is also provided.

PMME retrospective and real-time forecasts are assessed. For above normal and below normal categories, temperature forecasts outperform climatology for a large part of the globe. Precipitation forecasts are definitely more skillful than random guessing for the extratropics and climatological forecasts for the tropics. The skill of real-time forecasts lies within the range of the interannual variability of the historical forecasts.
The Smooth Signal Redundancy Hypothesis: A Functional Explanation for Relationships between Redundancy, Prosodic Prominence, and Duration in Spontaneous Speech
Authors: Aylett Matthew , Turk Alice
Published: December 2008

This paper explores two related factors which influence variation in duration, prosodic structure and redundancy in spontaneous speech. We argue that the constraint of producing robust communication while efficiently expending articulatory effort leads to an inverse relationship between language redundancy and duration. The inverse relationship improves communication robustness by spreading information more evenly across the speech signal, yielding a smoother signal redundancy profile.

We argue that prosodic prominence is a linguistic means of achieving smooth signal redundancy. Prosodic prominence increases syllable duration and coincides to a large extent with unpredictable sections of speech, and thus leads to a smoother signal redundancy.

The results of linear regressions carried out between measures of redundancy, syllable duration and prosodic structure in a large corpus of spontaneous speech confirm: (1) an inverse relationship between language redundancy and duration, and (2) a strong relationship between prosodic prominence and duration.

The fact that a large proportion of the variance predicted by language redundancy and prosodic prominence is nonunique suggests that, in English, prosodic prominence structure is the means with which constraints caused by a robust signal requirement are expressed in spontaneous speech.
Probability in the Grammar of German and Dutch: Interfixation in Triconstituent Compounds
Authors: Krott Andrea , Libben Gary , Jarema Gonia , Dressler Wolfgang , Schreuder Robert , Baayen Harald
Published: December 2008

This study addresses the possibility that interfixes in multiconstituent nominal compounds in German and Dutch are functional as markers of immediate constituent structure. We report a lexical statistical survey of interfixation in the lexicons of German and Dutch which shows that all interfixes of German and one interfix of Dutch are significantly more likely to appear at the major constituent boundary than expected under chance conditions. A series of experiments provides evidence that speakers of German and Dutch are sensitive to the probabilistic cues to constituent structure provided by the interfixes. Thus, our data provide evidence that probability is part and parcel of grammatical competence.