bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differentiating past events on a cone influenced by debris‐flow and snow avalanche activity – a dendrogeomorphological approach
Authors: Stoffel Markus , Bollschweiler Michelle , Hassler Gion‐Reto 
Published: May 2006

AbstractDendrogeomorphology was used to investigate past events on a cone affected by both debris flows and snow avalanches. We report on results of 520 cores from 251 injured Larix decidua Mill. and Picea abies (L.) Karst. trees sampled on the Birchbach cone (Swiss Alps). Detailed analysis of tree‐ring sequences allowed dating of 561 growth disturbances in individual trees for a 252 yr period, extending from 1750 to 2002, which could be attributed to 30 different event years. We then localized the position of rows of traumatic resin ducts (TRDs) within the tree ring so as to assess the intra‐seasonal position of damage. In agreement with data on the local growth period, TRDs located at the beginning of the new growth ring were considered the result of avalanche impacts that occurred during the dormant season or in earliest earlywood between late October and early May. In contrast, TRD found in late earlywood or within latewood were considered the result of periglacial debris‐flow activity, as these layers of the tree ring are locally formed between July and early October.For nine out of the 30 reconstructed event years, the intra‐seasonal timing of TRDs indicated that reactions must be the result of past snow avalanche activity. In 19 other event years, TRDs showed that damage has been caused between July and early October and, thus, through debris flows in the Birchbach torrent. Finally, the spatial patterns of trees showing reactions as a result of particular events were assessed so as to approximate the extent of past debris flows and snow avalanches. Copyright © 2006 John Wiley & Sons, Ltd.
Morphodynamics and climate controls of two aeolian blowouts on the northern Great Plains, Canada
Authors: Hugenholtz C. H. , Wolfe S. A. 
Published: May 2006

AbstractBlowouts are the most regionally pervasive active aeolian landform on the northern Great Plains of North America. This study reports a long‐term investigation into the morphological development of two adjacent blowouts in a continental dune field. The blowouts were monitored for a decade in the Bigstick Sand Hills of southwestern Saskatchewan, Canada. Topographic changes were determined from dense arrays of erosion pins in each blowout (1 per 4 m2, n = 171; and 1 per 16 m2, n = 150). Pin measurements were made 16 times between May 1994 and May 2004. Over the decade both blowouts expanded and more than doubled in volume. Differences in form–flow interactions have caused the larger of the two blowouts to deposit more than a metre of sediment within the deflation basin, and the smaller blowout to erode by more than a metre. A negative feedback effect was triggered when the larger blowout reached a critical size around 1994 (60 m × 36 m × 8·1 m, length × width × height) when sediment was no longer eroded from the deflation basin. A positive feedback in the smaller blowout continues to facilitate erosion from the deflation basin. Monthly observations since 2002 indicate that aspect plays an important role in the development of these blowouts by creating a spatial asymmetry in sediment availability. Sediment is more readily available throughout the year on south‐facing slopes, which receive greater insolation than north‐facing slopes and are often drier and more frequently thawed in this cold‐climate environment. Comparisons between climate data from a remote meteorological station 45 km to the southwest and sediment transport indices developed from the erosion pin data produced very few correlations significant at the 95 per cent confidence level. Nevertheless, the signs of the correlation coefficients indicate that sediment erosion and deposition in both blowouts respond similarly to the following climate variables recorded at the remote station: (i) the amount of precipitation, (ii) the transport capacity of the wind and (iii) transporting winds from a directional wedge between 180 and 330°. Taken altogether, the results from this study highlight the importance of climate and feedback effects in blowout development that may be extended to other blowouts in continental and coastal settings. Copyright © 2006 John Wiley & Sons, Ltd.
Physical modelling of fault scarp degradation under freeze–thaw cycles
Authors: Font M. , Lagarde J.‐L. , Amorese D. , Coutard J.‐P. , Dubois A. , Guillemet G. , Ozouf J.‐C. , Vedie E. 
Published: May 2006

AbstractPhysical modelling has been developed in order to simulate the effects of periglacial erosion processes on the degradation of slopes and scarps. Data from 41 experimental freeze–thaw cycles are presented. They attest to the efficiency of periglacial processes that control both erosion and changes in scarp morphology: (i) cryoexpulsion leads to an increase of scarp surface roughness and modifies significantly the internal structure of the active layer; (ii) combined effects of frost creep and gelifluction lead to slow and gradual downslope displacements of the active layer (0·3 cm/cycle); (iii) debris flows are associated with the most significant changes in scarp morphology and are responsible for the highest rate of scarp erosion; (iv) quantification of the erosion rate gives values close to 1 cm3 cm−2 for 41 freeze–thaw cycles. These experimental results are consistent with field data acquired along the La Hague fault scarp (Normandy, France) where an erosion rate of 4·6 ± 1 m3 m−2 per glacial stage has been computed from the volume of natural slope deposits stored during the Weichselian glacial stage. These results show that moist periglacial erosion processes could lead to an underestimation of Plio‐Quaternary deformation in the mid‐latitudes. Copyright © 2006 John Wiley & Sons, Ltd.
Experimental determination of saltating glass particle dispersion in a turbulent boundary layer
Authors: Wang H. T. , Zhang X. H. , Dong Z. B. , Ayrault M. 
Published: May 2006

AbstractA horizontal saltation layer of glass particles in air is investigated experimentally over a flat bed and also over a triangular ridge in a wind tunnel. Particle concentrations are measured by light scattering diffusion (LSD) and digital image processing, and velocities using particle image velocimetry (PIV). All the statistical moments of the particle concentration are determined such as mean concentration, root mean square concentration fluctuations, skewness and flatness coefficients. Over the flat bed, it is confirmed that the mean concentration decreases exponentially with height, the mean dispersion height being a significant length scale. It is shown that the concentration distribution follows quite well a lognormal distribution. Over the ridge, measurements were made at the top of the ridge and in the cavity region and are compared with measurements without the ridge. On the hill crest, particles are retarded, the saltation layer decreases in thickness and concentration is increased. Downwind of the ridge, particle flow behaves like a jet, in particular no particle return flow is observed. Copyright © 2006 John Wiley & Sons, Ltd.
Erosion in northwest Tibet from in‐situ‐produced cosmogenic 10Be and 26Al in bedrock
Authors: Kong Ping , Na Chunguang , Fink David , Ding Lin , Huang Feixin 
Published: May 2006

AbstractConcentrations of in‐situ‐produced cosmogenic nuclides 10Be and 26Al in quartz were measured by accelerator mass spectrometry for bedrock basalts and sandstones located in northwest Tibet. The effective exposure ages range between 23 and 134 ka (10Be) and erosion rates between 4·0 and 24 mm ka−1. The erosion rates are significantly higher than those in similarly arid Antarctica and Australia, ranging between 0·1 and 1 mm ka−1, suggesting that precipitation is not the major control of erosion of landforms. Comparison of erosion rates in arid regions with contrasting tectonic activities suggests that tectonic activity plays a more important role in controlling long‐term erosion rates. The obtained erosion rates are, however, significantly lower than the denudation rate of 3000–6000 mm ka−1 beginning at c. 5‐3 Ma in the nearby Godwin Austen (K2) determined by apatite fission‐track thermochronology. It appears that the difference in erosion rates within different time intervals is indicative of increased tectonic activity at c. 5–3 Ma in northwest Tibet. We explain the low erosion rates determined in this study as reflecting reduced tectonic activity in the last million years. A model of localized thinning of the mantle beneath northwest Tibet may account for the sudden increased tectonic activity at c. 5–3 Ma and the later decrease. Copyright © 2006 John Wiley & Sons, Ltd.
Essential oil composition of Pimpinella affinis Ledeb. from two localities in Iran
Authors: Askari F. , Sefidkon F. 
Published: May 2006

AbstractEssential oils were isolated by hydrodistillation from the stems plus leaves, inflorescences and seeds of Pimpinella affinis Ledeb. individually. The plants were collected from Khojir and Chaloos (north‐east and north of Tehran province, respectively). The yields of stem plus leaf, inflorescence and seed oils for the Khojir samples were 0.04%, 1.98% and 5.33% w/w and for the Chalous samples were 0.37%, 1.74% and 4.05% w/w, respectively. Limonene is a major constituent in the inflorescence and seed oils of the Khojir (47.9% and 90.5%, respectively) and Chalous samples (37.8% and 70.8%, respectively), whereas it was found in the stem plus leaf oil of the Khojir and the Chalous samples in low amounts (1.4% and 0.8%, respectively). γ‐Terpinen‐7‐al is the major constituent in the stem plus leaf and inflorescence oils of the Khojir (69.9% and 37.6%) and Chalous samples (72.8% and 49.1%), but was not found at all in the seed oils. Caryophyllene oxide (9.1%) was found in the stem plus leaf oil of the Khojir sample, and methyl eugenol (9.7%) and (E)‐nerolidol acetate (9.1%) in the seed oil of the Chalous sample. Copyright © 2006 John Wiley & Sons, Ltd.
RNA interference‐based functional dissection of the 17q12 amplicon in breast cancer reveals contribution of coamplified genes
Authors: Kao Jessica , Pollack Jonathan R. 
Published: May 2006

AbstractDNA amplification is a frequent occurrence in cancer genomes. While tumor amplicons may harbor known oncogenes “driving” amplification, amplicons rarely comprise only single genes. The potential functional contribution of coamplified genes remains largely unexplored. In breast cancer, 20–30% of tumors exhibit amplification within chromosome band 17q12, containing the ERBB2 oncogene. Analysis of array‐based comparative genomic hybridization and expression profiling data indicate that the minimum region of recurrent amplification (i.e., the amplicon “core”) at 17q12 includes two other genes, GRB7 and STARD3, which exhibit elevated expression when amplified. Western blot analysis confirms overexpression of each at the protein level in breast cancer cell lines SKBR3 and BT474 harboring amplification. In these cell lines (but not in control MCF7 breast cancer cells lacking 17q12 amplification), targeted knockdown of ERBB2 expression using RNA interference (RNAi) methods results in decreased cell proliferation, decreased cell‐cycle progression, and increased apoptosis. Notably, targeted knockdown of either GRB7 or STARD3 also leads to decreased cell proliferation and cell‐cycle progression, albeit to a lesser extent compared with ERBB2 knockdown. We conclude that the amplification and resultant overexpression of genes coamplified with ERBB2 at 17q12 can contribute to proliferation levels of breast cancer cells. Our findings validate the utility of RNAi in the functional interrogation of tumor amplicons, and provide evidence for a contribution of coamplified genes to tumor phenotypes. © 2006 Wiley‐Liss, Inc.
CpG island methylation of genes accumulates during the adenoma progression step of the multistep pathogenesis of colorectal cancer
Authors: Kim Young‐Ho , Petko Zsolt , Dzieciatkowski Slavomir , Lin Li , Ghiassi Mahan , Stain Steve , Chapman William C. , Washington Mary Kay , Willis Joseph , Markowitz Sanford D. , Grady William M. 
Published: May 2006

AbstractGenetic alterations occur during the adenoma‐carcinoma sequence of colon cancer formation and drive the initiation and progression of colon cancer formation. The aberrant methylation of genes is an alternate, epigenetic mechanism for silencing tumor suppressor genes in colon cancer. The aim of this study was to determine on a global and gene‐specific level the role of CpG island methylation in the initiation and progression of colon cancer. Consequently, we assessed the frequency of gene methylation in tumors representative of the commonly recognized histological steps of the adenoma‐carcinoma progression sequence through the analysis of eight genes previously identified to be methylated in colon cancer, MGMT, HLTF, MLH1, p14ARF, CDKN2A, TIMP3, THBS1, and CDH1. We observed that the proportion of tumors carrying methylated alleles increased from adenomas to adenocarcinomas but that the proportion of tumors with methylated alleles was not different between adenocarcinomas and metastases (69% versus 90%, P = 0.01 and 90% versus 81%, P > 0.05). The most substantial difference occurred between early and advanced adenomas (47% versus 84%, P = 0.018). Furthermore, we observed that the frequency of gene methylation at the different steps of the progression sequence varied between genes. Thus, the aberrant methylation of genes appears to increase most significantly during the progression of early adenomas to advanced adenomas, and the frequency of specific gene methylation at the different steps of the adenoma‐carcinoma progression sequence varies in a gene‐specific fashion. © 2006 Wiley‐Liss, Inc.
Neuropathologic and neuroinflammatory activities of HIV‐1‐infected human astrocytes in murine brain
Authors: Dou Huanyu , Morehead Justin , Bradley Jennifer , Gorantla Santhi , Ellison Brent , Kingsley Jeff , Smith Lynette M. , Chao Wei , Bentsman Galina , Volsky David J. , Gendelman Howard E. 
Published: May 2006

AbstractThe balance between astrocyte and microglia neuroprotection and neurotoxicity defines the tempo of neuronal dysfunction during HIV‐1‐associated dementia (HAD). Astrocytes maintain brain homeostasis and respond actively to brain damage by providing functional and nutritive neuronal support. In HAD, low‐level, continuous infection of astrocytes occurs, but the functional consequences of thisinfection are poorly understood. To this end, human fetal astrocytes (HFA) and monocyte‐derived macrophages (MDM) were infected with HIV‐1DJV and HIV‐1NL4‐3 (neurotropic and lymphotropic strains respectively) and a pseudotyped Vesicular Stomatitis Virus (VSV/HIV‐1NL4‐3) prior to intracranial injection into the basal ganglia of severe combined immunodeficient mice. Neuropathological and immunohistochemical comparisons for inflammatory and neurotoxic activities were performed amongst the infected cell types at 7 or 14 days. HIV‐1‐infected MDM induced significant increases in Mac‐1, glial fibrillary acidic protein, ionized calcium‐binding adapter molecule 1, and proinflammatory cytokine RNA and/or protein expression when compared with HSV/HIV‐1‐ and HIV‐1‐infected HFA and sham‐operated mice. Levels of neuron‐specific nuclear protein, microtubule‐associated protein 2, and neurofilament antigens were reduced significantly in the brain regions injected with human MDM infected with HIV‐1DJV or VSV/HIV‐1. We conclude that HIV‐1 infection of astrocytes leads to limited neurodegeneration, underscoring the early and active role of macrophage‐driven neurotoxicity in disease. © 2006 Wiley‐Liss, Inc.
Tobacco smoking, NAT2 acetylation genotype and breast cancer risk
Authors: Lissowska Jolanta , Brinton Louise A. , Zatonski Witold , Blair Aaron , Bardin‐Mikolajczak Alicja , Peplonska Beata , Sherman Mark E. , Szeszenia‐Da̧browska Neonila , Chanock Stephen , García‐Closas Montserrat 
Published: May 2006

AbstractThe role of active and passive cigarette smoking in breast cancer etiology remains controversial. Using data from a large population‐based case‐control study in Poland (2386 cases, 2502 controls) conducted during 2000–2003, we examined the associations between active and passive smoking overall and for different age categories. We also evaluated differences in risk by estrogen receptor (ER) and progesterone receptor (PR) status in tumors, and the potential modification of the smoking association by N‐acetyl transferase 2 (NAT2) genotype. Women ever exposed to passive smoking at home or at work had a risk of breast cancer similar to those never exposed to active or passive smoking (OR (95%CI) = 1.11 (0.85–1.46), and no trends were observed with increasing hours/day‐years of passive smoking exposure. Active smoking was associated with a significant increase in risk only among women younger than 45 years of age (OR (95%CI) = 1.95 (1.38–2.76); 1.15 (0.93–1.40); 0.91 (0.77–1.09) for <45, 45–55 and >55 years of age, respectively; p‐heterogeneity <0.001 for <45 vs. >55 years) and prevailed for both ER+ and ER− tumors. The smoking association among women <45 years was stronger for current than former smokers, and a significant trend was observed with duration of smoking (p = 0.04). NAT2 slow vs. rapid/intermediate acetylation genotype was not related to breast cancer risk (0.99 (0.87–1.13)), and did not significantly modify the smoking relationships. In conclusion, our data indicate that passive smoking is not associated with breast cancer risk; however, active smoking might be associated with an increased risk for early onset breast cancers. © 2006 Wiley‐Liss, Inc.
Mutations within Wnt pathway genes in sporadic colorectal cancers and cell lines
Authors: Suraweera Nirosha , Robinson James , Volikos Emmanuoil , Guenther Thomas , Talbot Ian , Tomlinson Ian , Silver Andrew 
Published: May 2006

AbstractWnt signaling pathway activation via mutation of genetic components, commonly adenomatous polyposis coli (APC), has a major role in colorectal cancer (CRC). Most components have not been assessed for mutation in sporadic CRC. We have analyzed AXIN2, CK1α, DKK1, GSK‐3β, SOX17, LRP6 and PPP2R1B, β‐catenin and APC in a collection of sporadic CRCs (n = 47) and CRC cell lines (CLs; n = 26). The CRC set was enriched for microsatellite unstable cancers (MSI+, 30%, 14/47). Somatic mutation was not found in CK1α, DKK1, LRP6, β‐catenin or GSK‐3β; but heterozygous frame‐shift mutations, and an in‐frame deletion mutation were detected in exon 7 of AXIN2 (CRCs, 11%, 5/47; CLs, 8%, 2/26). Our data refute a previous suggestion that a CRC‐related mutational hot‐spot occurred in the Huntington elongation A subunit TOR (HEAT) repeat 2 of PPP2R1B; this “hotspot” is, more likely, a rare germline polymorphism. An early investigation proposing a high mutational frequency in HEAT repeat 13 was not substantiated. A heterozygous SOX17 mutation (L194P) was also found in a cell line. APC gene mutations were identified in 64% (30/47) of cancers and 7% of these (2/30) had an additional mutation in another Wnt gene. Overall, 70% (33/47) of CRCs had a somatic mutation in a Wnt pathway gene. The number of tumors containing such a mutation was not significantly higher in MSI+ (57%, 8/14) compared to MSI− (76%, 25/33) cancers (p = 0.3, Fisher's exact test); APC mutation was significantly increased in the MSI− subgroup (p = 0.02, Fisher's exact test). Further, mutational screening of other Wnt pathway genes is warranted. © 2006 Wiley‐Liss, Inc.
Enhanced antitumor effect against human telomerase reverse transcriptase (hTERT) by vaccination with chemotactic‐hTERT gene‐modified tumor cell and the combination with anti‐4‐1BB monoclonal antibodies
Authors: Lin Xiaoyan , Zhou Chunxia , Wang Shengdian , Wang Dongmei , Ma Wenbo , Liang Xiao , Lin Chen , Wang Zheng , Li Jie , Guo Sujuan , Zhang Youhui , Zhang Shuren 
Published: May 2006

AbstractHuman telomerase reverse transcriptase (hTERT) represents an attractive target for cancer immunotherapy because hTERT is reactivated in most human tumors. In an attempt to develop an effective vaccine against most human cancers, we constructed chemotactic‐hTERT vaccine. Two hTERT fragments encoding multiple cytotoxic T lymphocyte and T helper cell epitopes were fused as a tumor antigen (named Te). The plasmid based DNA vaccine (pCCL21‐Te‐Fc) was constructed by linking human CCL21 and IgG Fc gene sequences to each end of Te. In poorly immunogenic B16F10 mouse melanoma model, DNA (pCCL21‐Te‐Fc) vaccination significantly inhibited tumor growth and all of the mice were dead by day 52. The immunization with pCCL21‐Te‐Fc‐modified tumor cells (B16/CCL21‐Te‐Fc) resulted in a higher antitumor effect than DNA vaccination and 25% of tumor‐bearing mice achieved long‐term survival (>120 days). The combined therapy of B16/CCL21‐Te‐Fc plus anti‐4‐1BB MAbs further enhanced the immune response, resulting in 75% of tumor‐bearing mice achieved long‐term survival (>120 days) in subcutaneous model and few lung nodules in pulmonary metastasis model. Rechallenge experiment showed that a persistent memory response was successfully induced by the combined therapy. In vivo depletion of lymphocytes indicated that CD8+ T cells were essential in the antitumor activity induced by B16/CCL21‐Te‐Fc plus anti‐4‐1BB MAbs, whereas NK cells and CD4+ T cells played substantial roles. The CTL activity induced by pCCL21‐Te‐Fc‐transfected PBMCs specifically lysed a variety of human leukocyte antigen‐matched and hTERT‐positive human tumor cells, suggesting pCCL21‐Te‐Fc could serve as a vaccine against most human cancers. © 2006 Wiley‐Liss, Inc.
Epigenetic inactivation of the SFRP genes is associated with drinking, smoking and HPV in head and neck squamous cell carcinoma
Authors: Marsit Carmen J. , McClean Michael D. , Furniss Constance Sloane , Kelsey Karl T. 
Published: May 2006

AbstractThe soluble frizzled receptor protein (SFRP) family encodes antagonists of the WNT pathway, and silencing of these genes, through promoter hypermethylation, leads to constitutive WNT signaling. In bladder cancers, hypermethylation of the SFRP genes occurs more often in current and former smokers and is a strong predictor of poor patient survival. Hence, we examined methylation of these genes in another tobacco‐related epithelial cancer, head and neck squamous cell carcinoma (HNSCC), to determine if the pattern of tobacco exposure again predicts the epigenetic alteration of these genes. Using methylation‐specific PCR, the prevalence of methylation of SFRP1, SFRP2, SFRP4 and SFRP5 was 35, 32, 35 and 29%, respectively among 350 HNSCC cases. Promoter methylation of SFRP1 occurred more often in both heavy (OR 3.5, 95% CI 0.9–13.7) and light drinkers (OR 3.7, 95% CI 1.0–14.3) compared to nondrinkers. SFRP4 promoter methylation, on the other hand, occurred at a higher prevalence in never smokers and former smokers than in current smokers, and also was independently associated with HPV16 viral DNA. A joint effects model of SFRP4 promoter methylation demonstrated that smoking status and HPV virus significantly interacted (p < 0.04) such that never smokers with HPV16 had an OR of SFRP4 methylation of 9.0 (95% CI 2.1–38.6). These results suggest that epigenetic alterations of the SFRP genes are highly prevalent in HNSCC, and that the clonal selection for these alterations is complex and may be related to the carcinogenic exposures that are known risk factors for this disease. © 2006 Wiley‐Liss, Inc.