bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating forest biomass components with hemispherical photography for Douglas-fir stands in northwest Oregon
Authors: Clark Joshua , Murphy Glen 
Published: May 2011

Accurately and quickly identifying inventories of forest biomass has become increasingly important for a variety of reasons. Current allometric equations require time-consuming tree-level measurements, but ground-based remote sensing could lead to faster estimates of forest biomass. Hemispherical photography (HP) is one potential technology that could estimate forest biomass quickly and efficiently. This analysis is based on a study in northwest Oregon where 15 Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) plots were destructively sampled, and 60 HPs (four per plot) were taken. One photograph was taken after removing each quartile of a plot (by basal area). Two subsets of bone-dry biomass were measured and estimated: (i) crown and branch biomass (CBB) and (ii) total aboveground biomass (AGB). AGB ranged from 136 to 423 Mg/ha, and CBB ranged from 26 to 68 Mg/ha. A regression analysis between actual and HP estimated biomass showed that the average of the top two and top three 18° zenith angles resulted in the highest correlation and lowest RMSE for both CBB and AGB, while an estimate of plant area index over the top three zenith angles had the lowest correlation. HP estimates are compared with two allometric equations: one based on a regional study and one based on a national compilation of studies.
Tree growth and disturbance dynamics in old-growth subalpine spruce forests of the Western Carpathians
Authors: Szewczyk Janusz , Szwagrzyk Jerzy , Muter Elżbieta 
Published: May 2011

Are the dynamics of natural subalpine spruce ( Picea abies (L.) Karst.) forests of central Europe governed by stand-replacing disturbances caused mostly by winds or by moderate disturbances resulting from bark beetle outbreaks? We analyzed tree-ring series from subalpine spruce forests in two mountain ranges of the Western Carpathians to determine the frequency and severity of disturbances and their effects on tree recruitment. The boundary-line method was employed to identify significant growth releases, interpreted as results of disturbances. In both study areas, major releases were not numerous but were regularly distributed over time. We found no evidence for stand-replacing disturbances. This result contrasts sharply with earlier findings from the Western Carpathians. The age structure of the forests studied indicates that the amount of tree recruitment was greater 150–200 years ago than in the subsequent 150 years. Our results suggest that stand dynamics in the forests analyzed are driven by numerous events of limited spatial extent and that stand-replacing disturbances are not necessary for the development of unimodal age structure.
Amelioration of doxorubicin-induced cardiotoxicity by deferiprone in rats
Authors: Ammar El-Sayed M. , Said Shehta A. , Suddek Ghada M. , El-Damarawy Sally L. 
Published: May 2011

The therapeutic usefulness of doxorubicin (Dox), an anthracycline antibiotic used as an anticancer agent, is limited by its cardiotoxicity. Dox-induced cardiotoxicity is mainly attributed to accumulation of reactive oxygen species and interaction of Dox with cellular iron metabolism. The present study investigated the effects of the iron chelator deferiprone (Def) against Dox-induced cardiotoxicity in rats. Dox (15 mg/kg) was injected intraperitoneally as a single dose, and Def (10 mg/kg) was administered orally for 10 days. Dox showed cardiotoxicity as evidenced by increased heart rate, elevated ST segment, prolonged QTc interval, and increased T wave amplitude. In addition, Dox enhanced aconitine cardiotoxicity by decreasing its dose, producing ventricular tachycardia. Administration of Def significantly attenuated Dox-induced electrocardiographic changes. Cardiotoxicity of Dox was confirmed biochemically by a significant elevation in serum creatine kinase-MB and lactate dehydrogenase activities as well as by myocardial malondialdehyde and reduced glutathione contents. Moreover, Dox caused a significant decrease in myocardial superoxide dismutase activity. Administration of Def significantly attenuated the biochemical changes. These results suggest that Def might be a potential cardioprotective agent against Dox-induced cardiotoxicity.
Orchidectomy attenuates impaired endothelial effects of a high-salt diet in Sprague–Dawley rats
Authors: Oloyo A.K. , Sofola O.A. , Anigbogu C.N. 
Published: May 2011

The effect of sex hormones on vascular reactivity is considered one of the underlying factors contributing to gender differences in cardiovascular functions and diseases. Experiments were designed to investigate the role of androgens in salt-induced hypertension by assessing the relaxation response of isolated aortic rings to acetylcholine and sodium nitroprusside in the presence or absence of l-nitroarginine methyl ester in Sprague–Dawley rats. The rats were either orchidectomized or sham-operated, with or without testosterone replacement, and were placed on a normal or high-salt diet for 6 weeks. The results indicate a significant increase (p < 0.001) in the mean arterial blood pressure of rats on the high-salt diet, when compared with control or orchidectomized rats. Orchidectomy elicited a reduction in mean arterial blood pressure (p < 0.01), while testosterone replacement normalized mean arterial blood pressure to values seen in intact rats on the high-salt diet. The high-salt diet reduced the relaxation response to acetylcholine both in the presence and absence of inhibition of endothelial nitric oxide synthase with l-nitroarginine methyl ester. Bilateral orchidectomy attenuated the impaired endothelial function induced by the high-salt diet in rats, but this was reversed by concomitant administration of testosterone, suggesting a role for androgens in enhancing long-term vascular smooth muscle tone and hence maintenance of high blood pressure in salt-induced hypertension.
Impact of random failures and attacks on Poisson and power-law random networks
Authors: Magnien Clémence , Latapy Matthieu , Guillaume Jean-Loup 
Published: May 2011

It has appeared recently that the underlying degree distribution of networks may play a crucial role concerning their robustness. Previous work insisted on the fact that power-law degree distributions induce high resilience to random failures but high sensitivity to attack strategies, while Poisson degree distributions are quite sensitive in both cases. Then much work has been done to extend these results.
We aim here at studying in depth these results, their origin, and limitations. We review in detail previous contributions in a unified framework, and identify the approximations on which these results rely. We then present new results aimed at clarifying some important aspects. We also provide extensive rigorous experiments which help evaluate the relevance of the analytic results.
We reach the conclusion that, even if the basic results are clearly important, they are in practice much less striking than generally thought. The differences between random failures and attacks are not so huge and can be explained with simple facts. Likewise, the differences in the behaviors induced by power-law and Poisson distributions are not as striking as often claimed.
Designing mobile interfaces for novice and low-literacy users
Authors: Medhi Indrani , Patnaik Somani , Brunskill Emma , Gautama S.N. Nagasena , Thies William , Toyama Kentaro 
Published: May 2011

While mobile phones have found broad application in bringing health, financial, and other services to the developing world, usability remains a major hurdle for novice and low-literacy populations. In this article, we take two steps to evaluate and improve the usability of mobile interfaces for such users. First, we offer an ethnographic study of the usability barriers facing 90 low-literacy subjects in India, Kenya, the Philippines, and South Africa. Then, via two studies involving over 70 subjects in India, we quantitatively compare the usability of different points in the mobile design space. In addition to text interfaces such as electronic forms, SMS, and USSD, we consider three text-free interfaces: a spoken dialog system, a graphical interface, and a live operator.
Our results confirm that textual interfaces are unusable by first-time low-literacy users, and error prone for literate but novice users. In the context of healthcare, we find that a live operator is up to ten times more accurate than text-based interfaces, and can also be cost effective in countries such as India. In the context of mobile banking, we find that task completion is highest with a graphical interface, but those who understand the spoken dialog system can use it more quickly due to their comfort and familiarity with speech. We synthesize our findings into a set of design recommendations.
High-throughput RNAi Screening Identifies a Role for TNK1 in Growth and Survival of Pancreatic Cancer Cells
Authors: Henderson Meredith C. , Gonzales Irma M. , Arora Shilpi , Choudhary Ashish , Trent Jeffrey M. , Von Hoff Daniel D. , Mousses Spyro , Azorsa David O. 
Published: May 2011

Abstract
To identify novel targets in pancreatic cancer cells, we used high-throughput RNAi (HT-RNAi) to select genes that, when silenced, would decrease viability of pancreatic cancer cells. The HT-RNAi screen involved reverse transfecting the pancreatic cancer cell line BxPC3 with a siRNA library targeting 572 kinases. From replicate screens, approximately 32 kinases were designated as hits, of which 22 kinase targets were selected for confirmation and validation. One kinase identified as a hit from this screen was tyrosine kinase nonreceptor 1 (TNK1), a kinase previously identified as having tumor suppressor-like properties in embryonic stem cells. Silencing of TNK1 with siRNA showed reduced proliferation in a panel of pancreatic cancer cell lines. Furthermore, we showed that silencing of TNK1 led to increased apoptosis through a caspase-dependent pathway and that targeting TNK1 with siRNA can synergize with gemcitabine treatment. Despite previous reports that TNK1 affects Ras and NF-κB signaling, we did not find similar correlations with these pathways in pancreatic cancer cells. Our results suggest that TNK1 in pancreatic cancer cells does not possess the same tumor suppressor properties seen in embryonic cells but seems to be involved in growth and survival. The application of functional genomics by using HT-RNAi screens has allowed us to identify TNK1 as a growth-associated kinase in pancreatic cancer cells. Mol Cancer Res; 9(6); 724–32. ©2011 AACR.
Antenatal Sildenafil Treatment Attenuates Pulmonary Hypertension in Experimental Congenital Diaphragmatic Hernia
Authors: Luong Christina , Rey-Perra Juliana , Vadivel Arul , Gilmour Greg , Sauve Yves , Koonen Debby , Walker Don , Todd Kathryn G. , Gressens Pierre , Kassiri Zamaneh , Nadeem Khurram , Morgan Beverly , Eaton Farah , Dyck Jason R. , Archer Stephen L. , Thébaud Bernard 
Published: May 2011

Background—
Lung hypoplasia and persistent pulmonary hypertension of the newborn limit survival in congenital diaphragmatic hernia (CDH). Unlike other diseases resulting in persistent pulmonary hypertension of the newborn, infants with CDH are refractory to inhaled nitric oxide (NO). Nitric oxide mediates pulmonary vasodilatation at birth in part via cyclic GMP production. Phosphodiesterase type 5 (PDE5) limits the effects of NO by inactivation of cyclic GMP. Because of the limited success in postnatal management of CDH, we hypothesized that antenatal PDE5 inhibition would attenuate pulmonary artery remodeling in experimental nitrofen-induced CDH.

Methods and Results—

Nitrofen administered at embryonic day 9.5 to pregnant rats resulted in a 60% incidence of CDH in the offspring and recapitulated features seen in human CDH, including structural abnormalities (lung hypoplasia, decreased pulmonary vascular density, pulmonary artery remodeling, right ventricular hypertrophy), and functional abnormalities (decreased pulmonary artery relaxation in response to the NO donor 2-(
N
,
N
-diethylamino)-diazenolate-2-oxide). Antenatal sildenafil administered to the pregnant rat from embryonic day 11.5 to embryonic day 20.5 crossed the placenta, increased fetal lung cyclic GMP and decreased active PDE5 expression. Antenatal sildenafil improved lung structure, increased pulmonary vessel density, reduced right ventricular hypertrophy, and improved postnatal NO donor 2-(
N
,
N
-diethylamino)-diazenolate-2-oxide–induced pulmonary artery relaxation. This was associated with increased lung endothelial NO synthase and vascular endothelial growth factor protein expression. Antenatal sildenafil had no adverse effect on retinal structure/function and brain development.

Conclusions—
Antenatal sildenafil improves pathological features of persistent pulmonary hypertension of the newborn in experimental CDH and does not alter the development of other PDE5-expressing organs. Given the high mortality/morbidity of CDH, the potential benefit of prenatal PDE5 inhibition in improving the outcome for infants with CDH warrants further studies.
Mechanical Coupling Between Myofibroblasts and Cardiomyocytes Slows Electric Conduction in Fibrotic Cell Monolayers
Authors: Thompson Susan A. , Copeland Craig R. , Reich Daniel H. , Tung Leslie 
Published: May 2011

Background—
After cardiac injury, activated cardiac myofibroblasts can influence tissue electrophysiology. Because mechanical coupling through adherens junctions provides a route for intercellular communication, we tested the hypothesis that myofibroblasts exert tonic contractile forces on the cardiomyocytes and affect electric propagation via a process of mechanoelectric feedback.

Methods and Results—

The role of mechanoelectric feedback was examined in transforming growth factor-β–treated monolayers of cocultured myofibroblasts and neonatal rat ventricular cells by inhibiting myofibroblast contraction and blocking mechanosensitive channels. Untreated (control) and transforming growth factor-β–treated (fibrotic) anisotropic monolayers were optically mapped for electrophysiological comparison. Longitudinal conduction velocity, transverse conduction velocity, and normalized action potential upstroke velocity (dV/dt
max
) significantly decreased in fibrotic monolayers (14.4±0.7 cm/s [mean±SEM], 4.1±0.3 cm/s [n=53], and 3.1±0.2% per ms [n=14], respectively) compared with control monolayers (27.2±0.8 cm/s, 8.5±0.4 cm/s [n=40], and 4.9±0.1% per ms [n=12], respectively). Application of the excitation-contraction uncoupler blebbistatin or the mechanosensitive channel blocker gadolinium or streptomycin dramatically increased longitudinal conduction velocity, transverse conduction velocity, and dV/dt
max
in fibrotic monolayers (35.9±1.5 cm/s, 10.3±0.6 cm/s [n=17], and 4.5±0.1% per ms [n=14], respectively). Similar results were observed with connexin43–silenced cardiac myofibroblasts. Spiral-wave induction in fibrotic monolayers also decreased after the aforementioned treatments. Finally, traction force measurements of individual myofibroblasts showed a significant increase with transforming growth factor-β, a decrease with blebbistatin, and no change with mechanosensitive channel blockers.

Conclusions—
These observations suggest that myofibroblast-myocyte mechanical interactions develop during cardiac injury, and that cardiac conduction may be impaired as a result of increased mechanosensitive channel activation owing to tension applied to the myocyte by the myofibroblast.
Implantable Cardioverter-Defibrillator Registry Risk Score Models for Acute Procedural Complications or Death After Implantable Cardioverter-Defibrillator Implantation
Authors: Haines David E. , Wang Yongfei , Curtis Jeptha 
Published: May 2011

Background—
Patients undergoing implantable cardioverter-defibrillator (ICD) implantation are at risk of postprocedural complications. However, we do not have a risk stratification schema to identify patients at high and low risk of adverse events.

Methods and Results—
We analyzed data from 268 701 ICD implants submitted to the ICD Registry and developed logistic regression models to identify variables most strongly associated with the risk of acute complications and/or in-hospital death. Overall, 3.2% of the population experienced an adverse event. A simple risk score consisting of 10 readily available variables successfully identified patients at high and low risk of complications. The variables included in the score and assigned points included: age ≥70 years (1 point), female (2 points), New York Heart Association class III (1 point) or IV (3 points), atrial fibrillation (1 point), prior valve surgery (3 points), chronic lung disease (2 points), blood urea nitrogen >30 (2 points), reimplantation for reasons other than battery change (6 points), ICD type dual chamber (2 points) or biventricular (4 points), and nonelective ICD implant (3 points). The risk of any in-hospital complication increased from 0.6% among patients with a score of ≤5 (8.4% of the population) to 8.4% among patients with ≥19 risk points (3.9% of the population).

Conclusions—
A simple risk score consisting of readily available clinical variables can identify high- and low-risk subsets of patients undergoing ICD implantation. This information can guide the physician in patient selection and determining the intensity of care required post procedure.
Regional Climate Models Add Value to Global Model Data: A Review and Selected Examples
Authors: Feser Frauke , Rockel Burkhardt , von Storch Hans , Winterfeldt Jörg , Zahn Matthias 
Published: May 2011

An important challenge in current climate modeling is to realistically describe small-scale weather statistics, such as topographic precipitation and coastal wind patterns, or regional phenomena like polar lows. Global climate models simulate atmospheric processes with increasingly higher resolutions, but still regional climate models have a lot of advantages. They consume less computation time because of their limited simulation area and thereby allow for higher resolution both in time and space as well as for longer integration times. Regional climate models can be used for dynamical down-scaling purposes because their output data can be processed to produce higher resolved atmospheric fields, allowing the representation of small-scale processes and a more detailed description of physiographic details (such as mountain ranges, coastal zones, and details of soil properties).
However, does higher resolution add value when compared to global model results? Most studies implicitly assume that dynamical downscaling leads to output fields that are superior to the driving global data, but little work has been carried out to substantiate these expectations. Here a series of articles is reviewed that evaluate the benefit of dynamical downscaling by explicitly comparing results of global and regional climate model data to the observations. These studies show that the regional climate model generally performs better for the medium spatial scales, but not always for the larger spatial scales.
Regional models can add value, but only for certain variables and locations—particularly those influenced by regional specifics, such as coasts, or mesoscale dynamics, such as polar lows. Therefore, the decision of whether a regional climate model simulation is required depends crucially on the scientific question being addressed.
Predicting the Seasonal Shift in Mosquito Populations Preceding the Onset of the West Nile Virus in Central Illinois
Authors: Westcott N. E. , Hilberg S. D. , Lampman R. L. , Alto B. W. , Bedel A. , Muturi E. J. , Glahn H. , Baker M. , Kunkel K. E. , Novak R. J. 
Published: May 2011

In the midwestern United States, the summertime rise in infection rate by the West Nile virus is associated with a seasonal shift in the abundance of two mosquito populations, Culex restuans and Culex pipiens. This seasonal shift usually precedes the time of the peak infection rate in mosquitoes by 2–3 weeks and generally occurs earlier in the summer with above normal temperatures and later in the summer with below-normal temperatures. Two empirical models were developed to predict this seasonal shift in mosquito species, or the “crossover,” and have been run operationally since 2004 by the Midwestern Regional Climate Center located at the Illinois State Water Survey. These models are based on daily temperature data and have been verified by use of a unique dataset of daily records of mosquito species abundance collected by the Illinois Natural History Survey. An unfortunate characteristic of the original temperature models was that the crossover date often was reached with little or no lead time. In 2009, the models were modified to incorporate National Weather Service (NWS) model output statistics (MOS) 10-day temperature forecasts. This paper evaluates the effectiveness of these models to predict the crossover date and thus the period of increased risk of West Nile virus in the Midwest.
For the 8-yr period from 2002 to 2009, 6 yr had at least one model predicting the crossover within one week of the actual crossover date, and for 7 yr at least one of the model predictions was within 2 weeks of the actual crossover date. Incorporation of MOS temperature forecasts for a 10-day period, although not substantially changing the predicted crossover date, greatly improved the forecast lead time by about 9 days. From a disease management point of view, this improvement in advanced notice is significant. In 2009, there was an unprecedented early crossover date and a failed forecast. The poor forecast was likely caused by an unusually early summer prolonged and intense heat wave, followed immediately by a record cold July.
Zonal Asymmetry of the Annular Mode and Its Downstream Subtropical Jet: An Idealized Model Study
Authors: Song Jie , Zhou Wen , Wang Xin , Li Chongyin 
Published: May 2011

AbstractThis study investigates linkages between the zonal asymmetry of the annular mode (AM) zonal pattern and the subtropical jet (STJ) over its downstream regions of the storm track by using an idealized model. Observational analyses show that the AM zonal patterns are more zonally asymmetric during days when the STJ downstream of the storm track is unusually strong, and vice versa. In the idealized model, the STJ downstream of the storm track is varied by introducing an additional zonally localized tropical heating. The model’s AM variability exhibits a nearly zonally uniform structure when there is no or only weak tropical heating. However, the signatures of the AM are locally strengthened in the heating sector; thus, the AM zonal pattern is zonally asymmetric when the tropical heating is large enough to create a strong STJ. The model results also show that the percentage of the variance explained by the AM, the persistence of the AM index, and the intensity of eddy feedback are also increased when the tropical heating becomes stronger. It is argued herein that the zonal asymmetry of the AM pattern is caused by the zonal asymmetry of the anomalous synoptic eddy forcing projecting on the AM, which is primarily due to the zonal asymmetry of the variations of the storm track between the nonheating and heating sectors.