bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deep-water erosional remnants in eastern offshore Trinidad as terrestrial analogs for teardrop-shaped islands on Mars: Implications for outflow channel formation
Authors: Moscardelli Lorena , Wood Lesli 
Published: May 2011

AbstractDiscovery of geomorphological elements such as valleys and channel-like features on the surface of Mars has prompted debate over alternative origins for these morphologies, including erosion by lava, liquid CO2, glaciation, and mass wasting events. Similarities between Martian geomorphological elements and those of certain terrestrial environments suggest that water processes were involved in the formation of some visible Martian landscapes. Recent advances in three-dimensional seismic reflectivity imaging techniques, drawn mainly from oil and gas exploration activities in deep-water regions of the world, have allowed us to describe a variety of internal stratigraphic architectures that resemble some geomorphological features observed in the circum–Chryse Planitia region of Mars. For example, erosional shadow remnants that have been described as components of deep-water mass transport deposits in the eastern offshore margin of Trinidad closely resemble teardrop-shaped islands that have been described at the downstream end of outflow channels within the circum–Chryse Planitia region. These observations suggest that the teardrop-shaped islands might have been formed as a result of catastrophic submarine mass movements similar to those documented within continental margins on Earth.
Quartz flakes in lakes: Microdebitage evidence for submerged Great Lakes prehistoric (Late Paleoindian–Early Archaic) tool-making sites
Authors: Sonnenburg Elizabeth P. , Boyce Joseph I. , Reinhardt Eduard G. 
Published: May 2011

AbstractExploration for submerged prehistoric archaeological sites in the Great Lakes (North America) is a major challenge due to difficulties in locating scant cultural artifacts in lake-bottom sediments. Stone tool microfragments (microdebitage, &lt;1 mm) can be abundant (&gt;106 per tool) and more dispersed around tool-making sites, but have not been identified previously in an underwater context. To evaluate their use as a submerged site indicator, microdebitage analysis was conducted on five lake sediment cores from a shallow lagoon adjacent to a long-occupied prehistoric site (McIntyre site, Rice Lake, Ontario). We identified 155 microdebitage fragments within a distinctive muddy peat horizon (2–2.5 m depth) using light microscopy and scanning electron microscopy methods. The microdebitage consisted of angular to very angular quartz fragments (400–1000 μm) with characteristic conchoidal fractures and flake scars produced by mechanical percussion. The microdebitage horizon had a distinctive bimodal particle size peak and contained a low-diversity soil thecamoebian assemblage (Phryaginella, Bullinularia sp.) indicative of a wetland environment that formed during an early Holocene shoreline transgression. Accelerator mass spectrometry 14C dating of wood fragments yielded ages of 9470–8760 ± 50 yr B.P. (11,070–9560 cal [calibrated] yr B.P.), indicating a Late Paleoindian–Early Archaic age for the deposit. Results demonstrate that coring and microdebitage analysis are effective tools in the search for underwater prehistoric sites and can be employed more broadly in exploration of submerged landscapes in the Great Lakes basins.
Polygonal sandcracks: Unique sedimentary desiccation structures in Bahamian ooid grainstone
Authors: Glumac Bosiljka , Curran H. Allen , Motti Sarah A. , Weigner Madeline M. , Pruss Sara B. 
Published: May 2011

AbstractSandcracks, which are ubiquitous in Holocene eolian and beach backshore carbonate grainstone on Alligator Point, Cat Island, Bahamas, resemble polygonal mudcracks, but formed in ooid sand without muddy matrix. In experiments on Cat Island beach sand, sediment surfaces cracked polygonally in the absence of mud or biofilms while drying at room temperature due to contraction generated by capillary effects related to surface tension attraction of interstitial water. Gravitational collapse of irregular open pores and repacking of sand grains due to loss of cohesion between particles caused by evaporation of water enhance the cracking process and appearance of polygons by providing space for cracks to expand. The polygons are held together by any remaining capillary moisture and associated meniscus cement, which precipitates as the sand dries. Polygonal sandcracks can be preserved by rapid lithification of carbonate sand, but have been documented only rarely from other localities because their formation requires well-sorted, well-rounded spherical grains rather than those making up the more common, heterogeneous skeletal and peloidal sediment in carbonate settings. Interpretation of this primary sedimentary desiccation structure provides new insights into sedimentation and diagenesis of ooid-rich deposits and can aid in recognizing ancient subaerial exposure horizons.
Enhanced nitrogen fixation in the immediate aftermath of the latest Permian marine mass extinction
Authors: Luo Genming , Wang Yongbiao , Algeo Thomas J. , Kump Lee R. , Bai Xiao , Yang Hao , Yao Le , Xie Shucheng 
Published: May 2011

AbstractThe carbon (δ13Corg) and nitrogen (δ15N) isotopic compositions of bulk organic matter were analyzed in two high-resolution Permian-Triassic transitional sections containing microbialite in south China. The results from these shallow-marine sections show that an abrupt negative shift in δ15N, from ∼+3‰ to ∼0‰, occurred immediately after the latest Permian mass extinction (LPE) in both sections, concurrent with a distinct negative shift in δ13Corg. The persistently low values of δ15N suggest that, following the LPE, microbial nitrogen fixation became the main source of biologically available nitrogen in the Nanpanjiang Basin and perhaps over a broader region of the eastern Paleotethys Ocean. Enhanced N fixation is probably indicative of the prevalence of stratified anoxic water masses characterized by intense denitrification and/or anaerobic ammonium oxidation at the time. Perturbation of the marine nitrogen cycle might have contributed to high temperatures following the main marine mass extinction through the release of the greenhouse gas N2O. The sharp declines in δ15N and δ13Corg may be ascribed to an abrupt change in shallow-water microbial communities, which differed in composition from contemporaneous deep-water communities.
Yoga respiratory training improves respiratory function and cardiac sympathovagal balance in elderly subjects: a randomised controlled trial
Authors: Santaella Danilo F , Devesa Cesar R S , Rojo Marcos R , Amato Marcelo B P , Drager Luciano F , Casali Karina R , Montano Nicola , Lorenzi-Filho Geraldo 
Published: May 2011

ObjectivesSince ageing is associated with a decline in pulmonary function, heart rate variability and spontaneous baroreflex, and recent studies suggest that yoga respiratory exercises may improve respiratory and cardiovascular function, we hypothesised that yoga respiratory training may improve respiratory function and cardiac autonomic modulation in healthy elderly subjects.Design76 healthy elderly subjects were enrolled in a randomised control trial in Brazil and 29 completed the study (age 68±6 years, 34% males, body mass index 25±3 kg/m2). Subjects were randomised into a 4-month training program (2 classes/week plus home exercises) of either stretching (control, n=14) or respiratory exercises (yoga, n=15). Yoga respiratory exercises (Bhastrika) consisted of rapid forced expirations followed by inspiration through the right nostril, inspiratory apnoea with generation of intrathoracic negative pressure, and expiration through the left nostril. Pulmonary function, maximum expiratory and inspiratory pressures (PEmaxand PImax, respectively), heart rate variability and blood pressure variability for spontaneous baroreflex determination were determined at baseline and after 4 months.ResultsSubjects in both groups had similar demographic parameters. Physiological variables did not change after 4 months in the control group. However, in the yoga group, there were significant increases in PEmax(34%, p<0.0001) and PImax(26%, p<0.0001) and a significant decrease in the low frequency component (a marker of cardiac sympathetic modulation) and low frequency/high frequency ratio (marker of sympathovagal balance) of heart rate variability (40%, p<0.001). Spontaneous baroreflex did not change, and quality of life only marginally increased in the yoga group.ConclusionRespiratory yoga training may be beneficial for the elderly healthy population by improving respiratory function and sympathovagal balance.Trial RegistrationCinicalTrials.gov identifier:NCT00969345; trial registry name: Effects of respiratory yoga training (Bhastrika) on heart rate variability and baroreflex, and quality of life of healthy elderly subjects.
Population-based trends in pregnancy hypertension and pre-eclampsia: an international comparative study
Authors: Roberts Christine L , Ford Jane B , Algert Charles S , Antonsen Sussie , Chalmers James , Cnattingius Sven , Gokhale Manjusha , Kotelchuck Milton , Melve Kari K , Langridge Amanda , Morris Carole , Morris Jonathan M , Nassar Natasha , Norman Jane E , Norrie John , Sørensen Henrik Toft , Walker Robin , Weir Christopher J 
Published: May 2011

ObjectiveThe objective of this study was to compare international trends in pre-eclampsia rates and in overall pregnancy hypertension rates (including gestational hypertension, pre-eclampsia and eclampsia).DesignPopulation data (from birth and/or hospital records) on all women giving birth were available from Australia (two states), Canada (Alberta), Denmark, Norway, Scotland, Sweden and the USA (Massachusetts) for a minimum of 6 years from 1997 to 2007. All countries used the 10th revision of theInternational Classification of Diseases, except Massachusetts which used the 9th revision. There were no major changes to the diagnostic criteria or methods of data collection in any country during the study period. Population characteristics as well as rates of pregnancy hypertension and pre-eclampsia were compared.ResultsAbsolute rates varied across the populations as follows: pregnancy hypertension (3.6% to 9.1%), pre-eclampsia (1.4% to 4.0%) and early-onset pre-eclampsia (0.3% to 0.7%). Pregnancy hypertension and/or pre-eclampsia rates declined over time in most populations. This was unexpected given that factors associated with pregnancy hypertension such as pre-pregnancy obesity and maternal age are generally increasing. However, there was also a downward shift in gestational age with fewer pregnancies reaching 40 weeks.ConclusionThe rate of pregnancy hypertension and pre-eclampsia decreased in northern Europe and Australia from 1997 to 2007, but increased in Massachusetts. The use of a different International Classification of Diseases coding version in Massachusetts may contribute to the difference in trend. Elective delivery prior to the due date is the most likely explanation for the decrease observed in Europe and Australia. Also, the use of interventions that reduce the risk of pregnancy hypertension and/or progression to pre-eclampsia (low-dose aspirin, calcium supplementation and early delivery for mild hypertension) may have contributed to the decline.
A Multistage Association Study Identifies a Breast Cancer Genetic Locus atNCOA7
Authors: Higginbotham Kathryn S.P. , Breyer Joan P. , Bradley Kevin M. , Schuyler Peggy A. , Plummer W. Dale , Freudenthal Marcia E. , Trentham-Dietz Amy , Newcomb Polly A. , Sanders Melinda E. , Page David L. , Parl Fritz F. , Egan Kathleen M. , Dupont William D. , Smith Jeffrey R. 
Published: May 2011

AbstractEstrogen metabolism and growth factor signaling pathway genes play key roles in breast cancer development. We evaluated associations between breast cancer and tagging single-nucleotide polymorphisms (SNP) of 107 candidate genes of these pathways using single allele- and haplotype-based tests. We first sought concordance of associations between two study populations: the Nashville Breast Cohort (NBC; 510 cases, 988 controls), and the Cancer Genetic Markers of Susceptibility (CGEMS) breast cancer study (1,145 cases, 1,142 controls). Findings across the two study populations were concordant at tagging SNPs of six genes, and at previously published SNPs of FGFR2. We sought further replication of results for EGFR, NCOA7, and FGFR2 in the independent Collaborative Breast Cancer Study (CBCS; 1,552 cases, 1,185 controls). Associations at NCOA7 and FGFR2 replicated across all three studies. The association at NCOA7 on 6q22.32, detected by a haplotype spanning the initial protein-coding exon (5′-rs9375411, rs11967627, rs549438, rs529858, rs490361, rs17708107-3′), has not been previously reported. The haplotype had a significant inverse association with breast cancer in each study [ORHet: 0.69 (NBC), 0.76 (CGEMS), 0.79 (CBCS)], and a meta-analysis ORHet of 0.75 (95% CI, 0.65–0.87, P = 1.4 × 10−4) in the combined study populations. The haplotype frequency was 0.07 among cases, and 0.09 among controls; homozygotes were infrequent and each ORHom was not significant. NCOA7 encodes a nuclear receptor coactivator that interacts with estrogen receptor α to modulate its activity. These observations provide consistent evidence that genetic variants at the NCOA7 locus may confer a reduced risk of breast cancer. Cancer Res; 71(11); 3881–8. ©2011 AACR.
Physical Activity after Diagnosis and Risk of Prostate Cancer Progression: Data from the Cancer of the Prostate Strategic Urologic Research Endeavor
Authors: Richman Erin L. , Kenfield Stacey A. , Stampfer Meir J. , Paciorek Alan , Carroll Peter R. , Chan June M. 
Published: May 2011

Abstract
Vigorous activity after diagnosis was recently reported to be inversely associated with prostate cancer–specific mortality. However, men with metastatic disease may decrease their activity due to their disease; thus, a causal interpretation is uncertain. We therefore prospectively examined vigorous activity and brisk walking after diagnosis in relation to risk of prostate cancer progression, an outcome less susceptible to reverse causation, among 1,455 men diagnosed with clinically localized prostate cancer. Cox proportional hazards regression was used to examine vigorous activity, nonvigorous activity, walking duration, and walking pace after diagnosis and risk of prostate cancer progression. We observed 117 events (45 biochemical recurrences, 66 secondary treatments, 3 bone metastases, 3 prostate cancer deaths) during 2,750 person-years. Walking accounted for nearly half of all activity. Men who walked briskly for 3 h/wk or more had a 57% lower rate of progression than men who walked at an easy pace for less than 3 h/wk (HR = 0.43; 95% CI: 0.21–0.91; P = 0.03). Walking pace was associated with decreased risk of progression independent of duration (HR brisk vs. easy pace = 0.52; 95% CI: 0.29–0.91; Ptrend = 0.01). Few men engaged in vigorous activity, but there was a suggestive inverse association (HR ≥3 h/wk vs. none = 0.63; 95% CI: 0.32–1.23; Ptrend = 0.17). Walking duration and total nonvigorous activity were not associated with risk of progression independent of pace or vigorous activity, respectively. Brisk walking after diagnosis may inhibit or delay prostate cancer progression among men diagnosed with clinically localized prostate cancer. Cancer Res; 71(11); 3889–95. ©2011 AACR.
Evolved Tumor Suppression: Why Are We So Good at Not Getting Cancer?
Authors: DeGregori James 
Published: May 2011

Abstract
The law of natural selection can be used to understand cancer development at the level of species as well as at the level of cells and tissues. Through this perspective, I seek to explain: (i) Why the lack of sufficient selective pressure to prevent cancers in old age helps explain the exponential increase in cancer incidence in the elderly. (ii) Why the evolution of long-lived animals necessitated the acquisition of potent tumor suppressive mechanisms. (iii) How the requirement to prevent inappropriate somatic cell expansion and cancer has constrained developmental and tissue architectural modalities. (iv) How the evolution of well-adapted stem cells with complex niche requirements has conferred resistance to oncogenic mutations, as phenotype-altering genetic change is almost always disadvantageous within a well-adapted cell population. (v) How the impairment of stem cell fitness, as occurs in old age, can promote selection for adaptive mutations and cancer initiation. (vi) Why differential maintenance of stem cell fitness may explain how different vertebrate species with enormous differences in life span and body size similarly avoid cancer through reproductive years. Cancer Res; 71(11); 3739–44. ©2011 AACR.
Roles of Sildenafil in Enhancing Drug Sensitivity in Cancer
Authors: Shi Zhi , Tiwari Amit K. , Patel Atish S. , Fu Li-Wu , Chen Zhe-Sheng 
Published: May 2011

Abstract
The phenomenon of multidrug resistance (MDR) has decreased the hope for successful cancer chemotherapy. The ATP-binding cassette (ABC) transporter superfamily is the largest transmembrane family. The overexpression of ABC transporters is a major determinant of MDR in cancer cells both in vitro and in vivo. Unfortunately, until recently, most of the strategies used to surmount ABC-transporter–mediated MDR have had limited success. An ideal modulator of MDR would be one that has a low liability to induce toxicity and alter the pharmacokinetic profile of antineoplastic drugs. Sildenafil, an inhibitor of cGMP-specific phosphodiesterase type 5, was found to significantly reverse ABC-transporter–mediated MDR. Our results indicate that sildenafil has differential inhibitory effects on ABC transporters: It significantly decreases the efflux activity of ABCB1 and ABCG2, but has no significant effects on ABCC1. Emerging evidence indicates that sildenafil and other phosphodiesterase type 5 inhibitors may enhance the sensitivity of certain types of cancer to standard chemotherapeutic drugs. Cancer Res; 71(11); 3735–8. ©2011 AACR.
An Epigenetic Marker Panel for Detection of Lung Cancer Using Cell-Free Serum DNA
Authors: Begum Shahnaz , Brait Mariana , Dasgupta Santanu , Ostrow Kimberly L. , Zahurak Marianna , Carvalho André L. , Califano Joseph A. , Goodman Steven N. , Westra William H. , Hoque Mohammad Obaidul , Sidransky David 
Published: May 2011

Abstract
Purpose: We investigated the feasibility of detecting aberrant DNA methylation of some novel and known genes in the serum of lung cancer patients.
Experimental Design: To determine the analytic sensitivity, we examined the tumor and the matched serum DNA for aberrant methylation of 15 gene promoters from 10 patients with primary lung tumors by using quantitative methylation-specific PCR. We then tested this 15-gene set to identify the more useful DNA methylation changes in the serum of a limited number of lung cancer patients and controls. In an independent set, we tested the six most promising genes (APC, CDH1, MGMT, DCC, RASSF1A, and AIM1) for further elucidation of the diagnostic application of this panel of markers.
Results: Promoter hypermethylation of at least one of the genes studied was detected in all 10 lung primary tumors. In majority of cases, aberrant methylation in serum DNA was accompanied by methylation in the matched tumor samples. In the independent set, using a single gene that had 100% specificity (DCC), 35.5% (95% CI: 25–47) of the 76 lung cancer patients were correctly identified. For patients without methylated DCC, addition of a logistic regression score that was based on the five remaining genes improved sensitivity from 35.5% to 75% (95% CI: 64–84) but decreased the specificity from 100% to 73% (95% CI: 54–88).
Conclusion: This approach needs to be evaluated in a larger test set to determine the role of this gene set in early detection and surveillance of lung cancer. Clin Cancer Res; 17(13); 4494–503. ©2011 AACR.
Genetic Aberrations Leading to MAPK Pathway Activation Mediate Oncogene-Induced Senescence in Sporadic Pilocytic Astrocytomas
Authors: Jacob Karine , Quang-Khuong Dongh-Anh , Jones David T.W. , Witt Hendrik , Lambert Sally , Albrecht Steffen , Witt Olaf , Vezina Catherine , Shirinian Margret , Faury Damien , Garami Miklos , Hauser Peter , Klekner Almos , Bognar Laszlo , Farmer Jean-Pierre , Montes Jose-Luis , Atkinson Jeffrey , Hawkins Cynthia , Korshunov Andrey , Collins V. Peter , Pfister Stefan M. , Tabori Uri , Jabado Nada 
Published: May 2011

AbstractPurpose: Oncogenic BRAF/Ras or NF1 loss can potentially trigger oncogene-induced senescence (OIS) through activation of the mitogen-activated protein kinase (MAPK) pathway. Somatic genetic abnormalities affecting this pathway occur in the majority of pilocytic astrocytomas (PA), the most prevalent brain neoplasm in children. We investigated whether OIS is induced in PA.Experimental Design: We tested expression of established senescence markers in three independent cohorts of sporadic PA. We also assessed for OIS in vitro, using forced expression of wild-type and V600E-mutant BRAF in two astrocytic cell lines: human telomerase reverse transcriptase (hTERT)-immortalized astrocytes and fetal astrocytes.Results: Our results indicate that PAs are senescent as evidenced by marked senescence-associated acidic β-galactosidase activity, low KI-67 index, and induction of p16INK4a but not p53 in the majority of 52 PA samples (46 of 52; 88.5%). Overexpression of a number of senescence-associated genes [CDKN2A (p16), CDKN1A (p21), CEBPB, GADD45A, and IGFBP7] was shown at the mRNA level in two independent PA tumor series. In vitro, sustained activation of wild-type or mutant BRAF induced OIS in both astrocytic cell lines. Loss of p16INK4a in immortalized astrocytes abrogated OIS, indicative of the role of this pathway in mediating this phenomenon in astrocytes. OIS is a mechanism of tumor suppression that restricts the progression of benign tumors. We show that it is triggered in PAs through p16INK4a pathway induction following aberrant MAPK activation.Conclusions: OIS may account for the slow growth pattern in PA, the lack of progression to higher-grade astrocytomas, and the high overall survival of affected patients. Clin Cancer Res; 17(14); 4650–60. ©2011 AACR.