bluuebunny/crossref_metadata_2025 huggingface dataset:
The Smoking Patterns of Women in Their Forties: Their Relationship to Later Osteoporosis
Authors: Brook Judith S. , Balka Elinor B. , Zhang Chenshu
Published: April 2012

Osteoporosis is prevalent among women 50 years of age and older and accounts for numerous fractures and the related deaths of many sufferers. In this study, 22.4% of the women reported having osteoporosis. Smoking contributes substantially to osteoporotic fractures. This study assessed how different trajectories of women's smoking, covering the ages 40 to 48 years, relate to osteoporosis at age 65. Trajectory analysis of tobacco use data reveals smoking patterns which may have differing relationships to osteoporosis. Logistic regression analyses revealed the varying relationships of different smoking patterns to osteoporosis. As hypothesized, the chronic/heavy smokers were significantly more likely than the non-smokers to report having osteoporosis. Quitters and moderate smokers did not differ significantly from non-smokers on the osteoporosis measure. Chronic/heavy smokers should not be the only focus of public health efforts to reduce smoking and the associated risks of osteoporosis. The findings also highlight the efficacy of women smokers quitting in their 40s in order to reduce their likelihood of contracting osteoporosis.
Realization of a fuzzy controller with fuzzy dynamic correction
Authors: Vichuzhanin Vladimir
Published: April 2012

This article features results from a fuzzy controller with fuzzy dynamic correction for the non-linear control of objects with variable parameters. The methods described herein have been used on a fuzzy proportional-differential (PD) controller, and our results show that fuzzy dynamic correction can reduce overshoot and shorten the settling time of the controlled parameters.
Health-Related Quality of Life of Australians with Parkinson Disease: A Comparison with International Studies
Authors: Soh Sze-Ee , McGinley Jennifer L. , Watts Jennifer J. , Iansek Robert , Morris Meg E.
Published: April 2012

Purpose: This study describes the health-related quality of life (HRQOL) of Australians living with Parkinson disease (PD) and compares the findings to international reports. Methods: The Parkinson's Disease Questionnaire-39 (PDQ-39) was used to measure HRQOL in 210 individuals with PD living in Australia. In parallel, a tailored literature search identified previous studies on HROQL in people with PD. A quantitative meta-analysis with a random-effects model was used to compare the HRQOL of individuals with PD living in Australia and other countries. Results: The mean PDQ-39 summary index (SI) score for this sample of Australians with PD was 20.9 (SD 12.7). Ratings for the dimension of social support and stigma were significantly lower than ratings for bodily discomfort, mobility, activities of daily living, cognition, and emotional well-being. Comparing the Australian and international PD samples revealed a significant heterogeneity in overall HRQOL (I2=97%). The mean PDQ-39 SI scores for Australians were lower, indicating better HRQOL relative to samples from other countries. Conclusions: This Australian sample with PD perceived their HRQOL as poor, although it was less severely compromised than that of international samples. While further research is required, these findings can inform the clinical decision-making processes of physiotherapists.
Dual regeneration of muscle and nerve by intravenous administration of human amniotic fluid–derived mesenchymal stem cells regulated by stromal cell–derived factor-1α in a sciatic nerve injury model
Authors: Yang Dar-Yu , Sheu Meei-Ling , Su Hong-Lin , Cheng Fu-Chou , Chen Ying-Ju , Chen Chun-Jung , Chiu Wen-Ta , Yiin Jia-Jean , Sheehan Jason , Pan Hung-Chuan
Published: April 2012

Object

Human amniotic fluid–derived mesenchymal stem cells (AFMSCs) have been shown to promote peripheral nerve regeneration. The expression of stromal cell–derived factor-1α (SDF-1α) in the injured nerve exerts a trophic effect by recruiting progenitor cells that promote nerve regeneration. In this study, the authors investigated the feasibility of intravenous administration of AFMSCs according to SDF-1α expression time profiles to facilitate neural regeneration in a sciatic nerve crush injury model.

Methods

Peripheral nerve injury was induced in 63 Sprague-Dawley rats by crushing the left sciatic nerve using a vessel clamp. The animals were randomized into 1 of 3 groups: Group I, crush injury as the control; Group II, crush injury and intravenous administration of AFMSCs (5 × 106 cells for 3 days) immediately after injury (early administration); and Group III, crush injury and intravenous administration of AFMSCs (5 × 106 cells for 3 days) 7 days after injury (late administration). Evaluation of neurobehavior, electrophysiological study, and assessment of regeneration markers were conducted every week after injury. The expression of SDF-1α and neurotrophic factors and the distribution of AFMSCs in various time profiles were also assessed.

Results

Stromal cell–derived factor-1α increased the migration and wound healing of AFMSCs in vitro, and the migration ability was dose dependent. Crush injury induced the expression of SDF-1α at a peak of 10–14 days either in nerve or muscle, and this increased expression paralleled the expression of its receptor, chemokine receptor type-4 (CXCR-4). Most AFMSCs were distributed to the lung during early or late administration. Significant deposition of AFMSCs in nerve and muscle only occurred in the late administration group. Significantly enhanced neurobehavior, electrophysiological function, nerve myelination, and expression of neurotrophic factors and acetylcholine receptor were demonstrated in the late administration group.

Conclusions

Amniotic fluid–derived mesenchymal stem cells can be recruited by expression of SDF-1α in muscle and nerve after nerve crush injury. The increased deposition of AFMSCs paralleled the expression profiles of SDF-1α and its receptor CXCR-4 in either muscle or nerve. Administration of AFMSCs led to improvements in neurobehavior and expression of regeneration markers. Intravenous administration of AFMSCs may be a promising alternative treatment strategy in peripheral nerve disorder.
Cenozoic Mammals and Climate Change: The Contrast between Coarse-Scale versus High-Resolution Studies Explained by Species Sorting
Authors: Prothero Donald
Published: April 2012

Many paleontologists have noticed the broadly similar patterns between the changes in Cenozoic mammalian diversity and taxonomic dominance and climate changes. Yet detailed studies of fossil population samples with fine-scale temporal resolution during episodes of climate change like the Eocene-Oligocene transition in the White River Group, and the late Pleistocene at Rancho La Brea tar pits, demonstrates that most fossil mammal species are static and show no significant microevolutionary response to major climate changes. This mismatch between patterns seems best explained by species sorting. As the punctuated equilibrium model demonstrated, over long time spans most fossil species are stable and do not respond to climate change. Instead, change occurs at the next hierarchical level, with species sorting adding and subtracting to the total diversity pattern revealed by coarse-scale taxon counting, apparently responding to longer-term changes in climate as revealed by proxies like the oxygen isotope record.
What is Jewish (If Anything) about Isaiah Berlin’s Philosophy?
Authors: Dubnov Arie M.
Published: April 2012

This paper has two central aims: First, to reappraise Isaiah Berlin’s political thought in a historically contextualized way, and in particular: to pay attention to a central conceptual tensions which animates it between, on the one hand, his famous definition of liberalism as resting on a negative concept of liberty and, on the other, his defense of cultural nationalism in general and Zionism in particular. Second, to see what do we gain and what do we lose by dubbing his philosophy Jewish. The discussion will proceed as follows: after describing the conceptual tension (Section 1), I will examine Berlin’s discussion of nationalism and explain why comparisons between him and Hans Kohn as well as communitarian interpretations of him are incomplete and have limited merit. I will continue with a brief discussion of Berlin’s Jewishness and Zionism (Section 3) and explain why I define this position “Diaspora Zionism”. The two concluding sections will discuss Berlin’s place within a larger Cold War liberal discourse (Section 5) and why I find it problematic to see his political writings as part of a Jewish political tradition (Section 6).
Transformation of Ground Vibration Signal for Debris-Flow Monitoring and Detection in Alarm Systems
Authors: Abancó Clàudia , Hürlimann Marcel , Fritschi Bruno , Graf Christoph , Moya José
Published: April 2012

Debris flows are fast mass movements formed by a mix of water and solid materials, which occur in steep torrents, and are a source of high risks for human settlements. Geophones are widely used to detect the ground vibration induced by passing debris flows. However, the recording of geophone signals usually requires storing a huge amount of data, which leads to problems in storage capacity and power consumption. This paper presents a method to transform and simplify the signals measured by geophones. The key input parameter is the ground velocity threshold, which removes the seismic noise that is not related to debris flows. A signal conditioner was developed to implement the transformation and the ground velocity threshold was set by electrical resistors. The signal conditioner was installed at various European monitoring sites to test the method. Results show that data amount and power consumption can be greatly reduced without losing much information on the main features of the debris flows. However, the outcome stresses the importance of choosing a ground vibration threshold, which must be accurately calibrated. The transformation is also suitable to detect other rapid mass movements and to distinguish among different processes, which points to a possible implementation in alarm systems.
Microbiological and clinical characteristics of diabetic foot infections in northern India
Authors: Tiwari Shalbha , Pratyush Daliparthy D , Dwivedi Awanindra , Gupta Sanjiv K , Rai Madhukar , Singh Surya K
Published: April 2012

Introduction:  India has the largest diabetic population of 50.8 million that could reach an epidemic proportion by 2030. Diabetic foot infection is one of the dreaded complications of diabetes.  Only a few studies that focus on patterns of diabetic foot infection in our region, where diabetic foot care is inadequate, are available. This study evaluated microbial and clinical characteristics of diabetic foot infections that will be helpful in taking appropriate measures for their management. Methodology: In this prospective study conducted during 2008-2009, sixty-two diabetic foot patients underwent detailed history, clinical examination, and laboratory investigations including parameters of systemic infections. Microbial culture and sensitivity were performed at the time of presentation. Results: Among 62 cases, 43.5% had mono-microbial infection, 35.5% had poly-microbial infections, and 21% had sterile culture. Among 82 bacteria isolated, 68% were Gram negative and 32% were Gram positive. Leukocyte counts were higher (16928±9642 versus 14593±6687 cells/mm3) and haemoglobin (7.9±2.4 versus 9.2±2.2 mg/dl) lower in poly-microbial compared to mono-microbial infections. Haemoglobin counts were lower and leukocyte counts higher in Gram-negative compared to Gram-positive infections. Patients with sterile cultures also had clinical evidence of persistent infection. Escherichia coli were the most common isolate and piperacillin/tazobactam showed highest sensitivity. Conclusions: Gram-negative bacteria were most prevalent in diabetic foot infection. It is not uncommon to have culture reports negative despite clinical evidence of infection. This study suggests that piperacillin/tazobactam should be the treatment of choice on an empirical basis prior to a definitive bacteriological study and in cases with negative culture reports.
Astrocytes, but Not Microglia, Rapidly Sense H2O2 via STAT6 Phosphorylation, Resulting in Cyclooxygenase-2 Expression and Prostaglandin Release
Authors: Park Soo Jung , Lee Jee Hoon , Kim Hee Young , Choi Youn Hee , Park Jung Sup , Suh Young Ho , Park Sang Myun , Joe Eun-hye , Jou Ilo
Published: April 2012

Emerging evidence has established that astrocytes, once considered passive supporting cells that maintained extracellular ion levels and served as a component of the blood–brain barrier, play active regulatory roles during neurogenesis and in brain pathology. In the current study, we demonstrated that astrocytes sense H2O2 by rapidly phosphorylating the transcription factor STAT6, a response not observed in microglia. STAT6 phosphorylation was induced by generators of other reactive oxygen species (ROS) and reactive nitrogen species, as well as in the reoxygenation phase of hypoxia/reoxygenation, during which ROS are generated. Src–JAK pathways mediated STAT6 phosphorylation upstream. Experiments using lipid raft disruptors and analyses of detergent-fractionated cells demonstrated that H2O2-induced STAT6 phosphorylation occurred in lipid rafts. Under experimental conditions in which H2O2 did not affect astrocyte viability, H2O2-induced STAT6 phosphorylation resulted in STAT6-dependent cyclooxygenase-2 expression and subsequent release of PGE2 and prostacyclin, an effect also observed in hypoxia/reoxygenation. Finally, PGs released from H2O2-stimulated astrocytes inhibited microglial TNF-α expression. Accordingly, our results indicate that ROS-induced STAT6 phosphorylation in astrocytes can modulate the functions of neighboring cells, including microglia, through cyclooxygenase-2 induction and subsequent release of PGs. Differences in the sensitivity of STAT6 in astrocytes (highly sensitive) and microglia (insensitive) to phosphorylation following brief exposure to H2O2 suggest that astrocytes can act as sentinels for certain stimuli, including H2O2 and ROS, refining the canonical notion that microglia are the first line of defense against external stimuli.
Autocrine TNF Is Critical for the Survival of Human Dendritic Cells by Regulating BAK, BCL-2, and FLIPL
Authors: Lehner Manfred , Kellert Beate , Proff Julia , Schmid Martina A. , Diessenbacher Philip , Ensser Armin , Dörrie Jan , Schaft Niels , Leverkus Martin , Kämpgen Eckhart , Holter Wolfgang
Published: April 2012

The life span of dendritic cells (DCs) is determined by the balance of pro- and antiapoptotic proteins. In this study, we report that serum-free cultured human monocyte-derived DCs after TLR stimulation with polyinosinic acid-polycytidylic acid or LPS underwent apoptosis, which was correlated with low TNF production. Apoptosis was prevented by the addition of exogenous TNF or by concomitant stimulation with R-848, which strongly amplified endogenous TNF production. Neutralization of TNF confirmed that DC survival was mediated by autocrine TNF induced either by stimulation with R-848 or by ligation of CD40. DCs stimulated by polyinosinic acid-polycytidylic acid or IFN-β, another known inducer of DC apoptosis, were characterized by high levels and activation of the proapoptotic protein BAK. The ratio of antiapoptotic BCL-2 to BAK correlated best with the survival of activated DCs. Addition of TNF increased this ratio but had little effect on BAX and XIAP. Knockdown experiments using small interfering RNAs confirmed that the survival of activated and also of immature DCs was regulated by BAK and showed that TNF was protective only in the presence of FLIPL. Together, our data demonstrate that the survival of DCs during differentiation and activation depends on autocrine TNF and that the inhibition of BAK plays an important role in this process.
Antigen-Specific IL-2 Secretion Correlates with NK Cell Responses after Immunization of Tanzanian Children with the RTS,S/AS01 Malaria Vaccine
Authors: Horowitz Amir , Hafalla Julius C. R. , King Elizabeth , Lusingu John , Dekker Denise , Leach Amanda , Moris Philippe , Cohen Joe , Vekemans Johan , Villafana Tonya , Corran Patrick H. , Bejon Philip , Drakeley Chris J. , von Seidlein Lorenz , Riley Eleanor M.
Published: April 2012

RTS,S/AS01, a vaccine targeting pre-erythrocytic stages of Plasmodium falciparum, is undergoing clinical trials. We report an analysis of cellular immune response to component Ags of RTS,S—hepatitis B surface Ag (HBs) and P. falciparum circumsporozoite (CS) protein—among Tanzanian children in a phase IIb RTS,S/AS01E trial. RTS,S/AS01 E vaccinees make stronger T cell IFN-γ, CD69, and CD25 responses to HBs peptides than do controls, indicating that RTS,S boosts pre-existing HBs responses. T cell CD69 and CD25 responses to CS and CS-specific secreted IL-2 were augmented by RTS,S vaccination. Importantly, more than 50% of peptide-induced IFN-γ+ lymphocytes were NK cells, and the magnitude of the NK cell CD69 response to HBs peptides correlated with secreted IL-2 concentration. CD69 and CD25 expression and IL-2 secretion may represent sensitive markers of RTS,S-induced, CS-specific T cells. The potential for T cell-derived IL-2 to augment NK cell activation in RTS,S-vaccinated individuals, and the relevance of this for protection, needs to be explored further.
Synchronization of Dendritic Cell Activation and Antigen Exposure Is Required for the Induction of Th1/Th17 Responses
Authors: Kamath Arun T. , Mastelic Béatris , Christensen Dennis , Rochat Anne-Françoise , Agger Else Marie , Pinschewer Daniel D. , Andersen Peter , Lambert Paul-Henri , Siegrist Claire-Anne
Published: April 2012

The dendritic cell (DC) targeting/activation patterns required to elicit Th1/Th17 responses remain undefined. One postulated requirement was that of a physical linkage between Ags and immunomodulators. Accordingly, the separate same-site administration of Ag85B–ESAT-6 (hybrid-1 protein; H1), a mycobacterial fusion Ag, and the CAF01 liposome-based adjuvant induced similar Ab and weak Th2 responses as those of coformulated H1/CAF01 but failed to elicit Th1/Th17 responses. Yet, this separate same-site injection generated the same type and number of activated Ag+/adjuvant+ DCs in the draining lymph nodes (LN) as that of protective H1/CAF01 immunization. Thus, targeting/activating the same DC population by Ag and adjuvant is not sufficient to elicit Th1/Th17 responses. To identify the determinants of Th1/Th17 adjuvanticity, in vivo tracking experiments using fluorescently labeled Ag and adjuvant identified that a separate same-site administration elicits an additional early Ag+/adjuvant− DC population with a nonactivated phenotype, resulting from the earlier targeting of LN DCs by H1 than by CAF01 molecules. This asynchronous targeting pattern was mimicked by the injection of free H1 prior to or with, but not after, H1/CAF01 or H1/CpG/ aluminum hydroxide immunization. The injection of soluble OVA similarly prevented the induction of Th1 responses by OVA/CAF01. Using adoptively transferred OT-2 cells, we show that the Ag targeting of LN DCs prior to their activation generates nonactivated Ag-pulsed DCs that recruit Ag-specific T cells, trigger their initial proliferation, but interfere with Th1 induction in a dose-dependent manner. Thus, the synchronization of DC targeting and activation is a critical determinant for Th1/Th17 adjuvanticity.
Immunoglobulin Fc Fragment Tagging Allows Strong Activation of Endogenous CD4 T Cells To Reshape the Tumor Milieu and Enhance the Antitumor Effect of Lentivector Immunization
Authors: Hong Yuan , Peng Yibing , Xiao Haiyan , Mi Michael , Munn David , He Yukai
Published: April 2012

A major problem with current cancer vaccines is that the induction of CD8 immune responses is rarely associated with antitumor benefits, mainly owing to multiple immune suppressions in established tumor lesions. In this study, we investigated if and how activation of endogenous CD4 T cells could be achieved to influence the suppressive tumor milieu and antitumor effect. We engineered a lentivector (lv) to express a nominal fusion Ag composed of hepatitis B surface protein and IgG2a Fc fragment (HBS-Fc-lv) to increase the magnitude of CD8 response but, more importantly, to induce effective coactivation of CD4 T cells. We found that, remarkably, immunization with HBS-Fc-lv caused significant regression of established tumors. Immunologic analysis revealed that, compared with HBS-lv without Fc fragment, immunization with HBS-Fc-lv markedly increased the number of functional CD8 and CD4 T cells and the level of Th1/Tc1-like cytokines in the tumor while substantially decreasing the regulatory T cell ratio. The favorable immunologic changes in tumor lesions and the improvement of antitumor effects from HBS-Fc-lv immunization were dependent on the CD4 activation, which was Fc receptor mediated. Adoptive transfer of CD4 T cells from the HBS-Fc-lv–immunized mice could activate endogenous CD8 T cells in an IFN-γ–dependent manner. We conclude that endogenous CD4 T cells can be activated by lv expressing Fc-tagged Ag to provide another layer of help—that is, creating a Th1/Tc1-like proinflammatory milieu within the tumor lesion to boost the effector phase of immune responses in enhancing the antitumor effect.
Dissecting Mechanisms of Immunodominance to the Common Tuberculosis Antigens ESAT-6, CFP10, Rv2031c (hspX), Rv2654c (TB7.7), and Rv1038c (EsxJ)
Authors: Lindestam Arlehamn Cecilia S. , Sidney John , Henderson Ryan , Greenbaum Jason A. , James Eddie A. , Moutaftsi Magdalini , Coler Rhea , McKinney Denise M. , Park Daniel , Taplitz Randy , Kwok William W. , Grey Howard , Peters Bjoern , Sette Alessandro
Published: April 2012

Diagnosis of tuberculosis often relies on the ex vivo IFN-γ release assays QuantiFERON-TB Gold In-Tube and T-SPOT.TB. However, understanding of the immunological mechanisms underlying their diagnostic use is still incomplete. Accordingly, we investigated T cell responses for the TB Ags included in the these assays and other commonly studied Ags: early secreted antigenic target 6 kDa, culture filtrate protein 10 kDa, Rv2031c, Rv2654c, and Rv1038c. PBMC from latently infected individuals were tested in ex vivo ELISPOT assays with overlapping peptides spanning the entirety of these Ags. We found striking variations in prevalence and magnitude of ex vivo reactivity, with culture filtrate protein 10 kDa being most dominant, followed by early secreted antigenic target 6 kDa and Rv2654c being virtually inactive. Rv2031c and Rv1038c were associated with intermediate patterns of reactivity. Further studies showed that low reactivity was not due to lack of HLA binding peptides, and high reactivity was associated with recognition of a few discrete dominant antigenic regions. Different donors recognized the same core sequence in a given epitope. In some cases, the identified epitopes were restricted by a single specific common HLA molecule (selective restriction), whereas in other cases, promiscuous restriction of the same epitope by multiple HLA molecules was apparent. Definition of the specific restricting HLA allowed to produce tetrameric reagents and showed that epitope-specific T cells recognizing either selectively or promiscuously restricted epitopes were predominantly T effector memory. In conclusion, these results highlight the feasibility of more clearly defined TB diagnostic reagent.
Mesenchymal Cells Regulate Retinoic Acid Receptor-Dependent Cortical Thymic Epithelial Cell Homeostasis
Authors: Sitnik Katarzyna M. , Kotarsky Knut , White Andrea J. , Jenkinson William E. , Anderson Graham , Agace William W.
Published: April 2012

The vitamin A metabolite and transcriptional modulator retinoic acid (RA) is recognized as an important regulator of epithelial cell homeostasis in several tissues. Despite the known importance of the epithelial compartment of the thymus in T cell development and selection, the potential role of RA in the regulation of thymic cortical and medullary epithelial cell homeostasis has yet to be addressed. In this study, using fetal thymus organ cultures, we demonstrate that endogenous RA signaling promotes thymic epithelial cell (TEC) cell-cycle exit and restricts TEC cellularity preferentially in the cortical TEC compartment. Combined gene expression, biochemical, and functional analyses identified mesenchymal cells as the major source of RA in the embryonic thymus. In reaggregate culture experiments, thymic mesenchyme was required for RA-dependent regulation of TEC expansion, highlighting the importance of mesenchyme-derived RA in modulating TEC turnover. The RA-generating potential of mesenchymal cells was selectively maintained within a discrete Ly51intgp38+ subset of Ly51+ mesenchyme in the adult thymus, suggesting a continual role for mesenchymal cell-derived RA in postnatal TEC homeostasis. These findings identify RA signaling as a novel mechanism by which thymic mesenchyme influences TEC development.
Antigen-Independent Differentiation and Maintenance of Effector-like Resident Memory T Cells in Tissues
Authors: Casey Kerry A. , Fraser Kathryn A. , Schenkel Jason M. , Moran Amy , Abt Michael C. , Beura Lalit K. , Lucas Philip J. , Artis David , Wherry E. John , Hogquist Kristin , Vezys Vaiva , Masopust David
Published: April 2012

Differentiation and maintenance of recirculating effector memory CD8 T cells (TEM) depends on prolonged cognate Ag stimulation. Whether similar pathways of differentiation exist for recently identified tissue-resident effector memory T cells (TRM), which contribute to rapid local protection upon pathogen re-exposure, is unknown. Memory CD8αβ+ T cells within small intestine epithelium are well-characterized examples of TRM, and they maintain a long-lived effector-like phenotype that is highly suggestive of persistent Ag stimulation. This study sought to define the sources and requirements for prolonged Ag stimulation in programming this differentiation state, including local stimulation via cognate or cross-reactive Ags derived from pathogens, microbial flora, or dietary proteins. Contrary to expectations, we found that prolonged cognate Ag stimulation was dispensable for intestinal TRM ontogeny. In fact, chronic antigenic stimulation skewed differentiation away from the canonical intestinal T cell phenotype. Resident memory signatures, CD69 and CD103, were expressed in many nonlymphoid tissues including intestine, stomach, kidney, reproductive tract, pancreas, brain, heart, and salivary gland and could be driven by cytokines. Moreover, TGF-β–driven CD103 expression was required for TRM maintenance within intestinal epithelium in vivo. Thus, induction and maintenance of long-lived effector-like intestinal TRM differed from classic models of TEM ontogeny and were programmed through a novel location-dependent pathway that was required for the persistence of local immunological memory.
Endoscopic therapy for Barrett′s esophagus
Authors: Shaheen Nicholas J.
Published: April 2012

Barrett’s esophagus (BE) is the precursor lesion to esophageal adenocarcinoma. This cancer has undergone a rapid increase in incidence in Western societies in the last 30 years. Current practices seek to lower the risk of death from this cancer by performing screening upper endoscopy on those with chronic reflux symptoms, and then surveillance upper endoscopy on those found to have BE at periodic intervals. While this approach is intuitively appealing, no data substantiate a decreased cancer risk with these practices, and substantial issues limit the effectiveness of this approach. This article outlines the current approaches to BE, their shortcomings, and presents data supporting the use of endoscopic therapy for subjects with BE and dysplasia. A significant and growing literature supports the use of endoscopic therapy in BE, and this approach, combined with improved risk stratification, may improve our care of subjects with BE.
Endoscopic management of benign biliary strictures: Possibility or exercise in futility?
Authors: Deprez Pierre H.
Published: April 2012

Benign biliary strictures for which endoscopic treatment is proposed are mostly related to liver transplantation or chronic pancreatitis (one third of cases each) and, less frequently, to other causes (e. g., cholecystectomy, sphincterotomy). The question of futility of exercise may therefore be of importance before embarking in these techniques. Endoscopic treatment of iatrogenic (post-operative) benign strictures may be considered as the gold standard since 90% of success is achieved with multiple stent placement. In strictures due to chronic pancreatitis, success rates are lower and surgery may be an appropriate alternative, although it may not be futile to propose an endoscopic try, especially when strictures are related to acute pancreatitis, pseudocyst obstruction or any reversible pancreatic cause of obstruction. In sclerosing cholangitis, endoscopic management is also focused on detection of malignancy. It should therefore not be considered as a futile exercise, but indications and aims of endotherapy should be discussed in a multidisciplinary team involving gastroenterologists, radiologists, and surgical specialists.
Reconstruction of the carbon isotopic composition of methane over the last 50 yr based on firn air measurements at 11 polar sites
Authors: Sapart C. J. , Martinerie P. , Chappellaz J. , van de Wal R. S. W. , Sperlich P. , van der Veen C. , Bernard S. , Sturges W. T. , Blunier T. , Witrant E. , Schwander J. , Etheridge D. , Röckmann T.
Published: April 2012

Abstract. Methane is a strong greenhouse gas and large uncertainties exist concerning the future evolution of its atmospheric abundance. Analyzing methane atmospheric mixing and stable isotope ratios in air trapped in polar ice sheets helps reconstructing the evolution of its sources and sinks in the past. This is important to improve predictions of atmospheric CH4 mixing ratios in the future under the influence of a changing climate. We present an attempt to reconcile methane carbon isotope records from 11 firn sites from both Greenland and Antarctica to reconstruct a consistent δ13C(CH4) history over the last 50 yr. In the firn, the atmospheric signal is altered mainly by diffusion and gravitation. These processes are taken into account by firn transport models. We show that isotope reconstructions from individual sites are not always mutually consistent among the different sites. Therefore we apply for the first time a multisite isotope inversion to reconstruct an atmospheric isotope history that is constrained by all individual sites, generating a multisite "best-estimate" scenario. This scenario is compared to ice core data, atmospheric air archive results and direct atmospheric monitoring data.
Global distributions of C2H6, C2H2, HCN, and PAN retrieved from MIPAS reduced spectral resolution measurements
Authors: Wiegele A. , Glatthor N. , Höpfner M. , Grabowski U. , Kellmann S. , Linden A. , Stiller G. , von Clarmann T.
Published: April 2012

Abstract. Vertical profiles of mixing ratios of C2H6, C2H2, HCN, and PAN were retrieved from MIPAS reduced spectral resolution nominal mode limb emission measurements. The retrieval strategy follows that of the analysis of MIPAS high resolution measurements, with occasional adjustments to cope with the reduced spectral resolution under which MIPAS is operated since 2005. MIPAS measurements from January 2005 to January 2010 have been analyzed with special emphasis on October 2007. Largest mixing ratios are found in the troposphere, and reach 1.2 ppbv for C2H6, 1 ppbv for HCN, 600 pptv for PAN, and 450 pptv for C2H2. The estimated precisions in case of significantly enhanced mixing ratios (including measurement noise and propagation of uncertain parameters randomly varying in the time domain) and altitude resolution are typically 10%, 3–4.5 km for C2H6, 15%, 4–6 km for HCN, 6%, 2.5–3.5 km for PAN, and 7%, 2.5–4 km for C2H2.
Past and recent trends in the western Black Sea storminess
Authors: Valchev N. N. , Trifonova E. V. , Andreeva N. K.
Published: April 2012

Abstract. Storms are one of the most important phenomena producing coastal hazards and endangering human life and activities. In recent decades storm climate has become a subject of increased public awareness and knowledge of this issue can help the society to meet future challenges related to extreme storm manifestation. Therefore, the goal of this study is to assess trends in past and recent storminess in the western Black Sea. The analysis of storm climate is based on a continuous hindcast dataset covering a substantial historical time-span of 63 yr (1948–2010). It was used to create a storm population and to estimate properties describing storminess (proxies). This was done by introduction of criteria allowing separation of events with low probability of occurrence and at the same time keeping the information on their pattern, i.e. properties of storm phases. Eleven storminess proxies were analysed and the most indicative appeared to be storm duration; integral, mean and specific storm wave energy; and wind velocity and direction, which were obtained for each storm season. While experiencing significant variability on a quasi-decadal scale, no significant upward or downward trends in storminess were detected. For almost all proxies, an increasing trend until the 1980s or the 1990s and a return to average or even calm conditions in the late 2000s are traceable. On this background, a steady although not significant increase of wind velocity was detected. Results also indicate an alteration of storm pattern, manifested as shortening of storm duration due to a shift of the prevailing direction of storm forcing winds to the north. Nevertheless, incident wave energy in the storms' most intense phase remains significant. The obtained results are discussed with regard to the influence of the North Atlantic Oscillation on the hydrometeorological pattern of the Black Sea region as a part of the European-Atlantic area, in particular with respect to the cyclonic activity.
A MODEL FOR PREDICTING THE SEDIMENTOLOGICAL FEATURES OF TURBIDITE DEPOSITS.
Authors: MULDER T. , SYVITSKI J.P.M.
Published: April 2012

A numerical model useful for the prediction of the runout distance, deposit dimensions, and internal properties of turbidity current deposits is proposed. The model uses an integrated formulation of the Chezy equation and includes geotechnical properties (shear strength) of seafloor sediments. The model is applied to a historical flood of the Saguenay River (Quebec, Canada) that created a month-long turbidity current that flowed along the seafloor of the Saguenay Fjord. Model simulation of plume acceleration includes the effects of fluid drag at both the bottom and top of the plume, and grain friction within the plume is modelled as a function of volumetric concentration. Entrainment of sea water is computed to increase the volume of the plume by a factor of five. The model also includes the effects of plume pushing as a function of the rising and the falling limbs of the flood event. Sediment deposition is assessed using removal rate values published by Syvitski and Lewis (1992). Deposition of sediment depends very much on the phase of the river flood event. Measured peaks in the thickness of the turbidite deposit are simulated by the model and correspond to a progressive shift seaward in the location where deposition begins. During the initial phase of the flood event, and until the peak discharge, the turbidite is inversely graded and coarse particles (sand and core silts) represents more than 75% of the weight of the sediment deposited. During the decreasing discharge phase, initial deposition progressively shifts landward and deposition of the finer size fractions (medium silts and finer) dominate. The simulated turbidite is then well graded and matches both core lithology and deposit thickness and runout distance. Our numerical model can also be applied to large ignitive turbidity current events and their deposits, providing a useful tool in the prediction of reservoir properties of submarine fans, e.g. porosity and permeability.
DETAILED STRATAL CORRELATION AND STACKING PATTERNS OF THE GREMIASCO AND LOWER CASTAGNOLA TURBIDITE SYSTEMS, TERTIARY PIEDMONT BASIN, NORTHWESTERN ITALY
Authors: BARUFFINI LUCA , CAVALLI CARLO , PAPANI LORENZO
Published: April 2012

The Gremiasco and lower Castagnola turbidite systems, in the syn-collisional Tertiary Piedmont Basin, northwestern Italy, are described and compared. Although belonging to the same basin-fill succession, these two systems show marked differences in terms of facies, stacking patterns, and geometries of sandstone bodies. The Gremiasco turbidite system was deposited by small-volume, sand-rich gravity flows that gave rise to thick sandstone beds showing rapid lateral facies changes. The system can be subdivided into three subunits, each characterized by its own geometry and stacking pattern: the differences observed between the subunits are mainly a function of local synsedimentary deformation. The lower Castagnola turbidite system was laid down by relatively large-volume gravity flows that generated thin to very thick sandstone beds showing no facies nor thickness variations over some kilometres. Based on their unusual thickness and features, most of these beds are intrepreted as seismoturbidites. The impressively isopachous geometry of the lower Castagnola system shows that synsedimentary structural deformation was virtually absent in the basin, whereas it played a major role in the initiation of gravity flows.
INTERNAL ARCHITECTURE OF A CHANNEL-LEVEE COMPLEX, CERRO TORO FORMATION, SOUTHERN CHILE
Authors: DEVRIES MICHAEL B. , LINDHOLM ROSANNE M.
Published: April 2012

Well tests have demonstrated that levee/overbank deposits in the Gulf of Mexico intraslope basins can be economically productive reservoirs with good flow rates. However, very little has been published on the internal reservoir geometry of deep-water levee deposits or on potential sources of reservoir heterogeneity on the interwell-scale. Depositional features that can affect estimates of hydrocarbon volume, production strategy, and reserves are best observed and explained from outcrop. Unfortunately, levee/overbank outcrops weather easily due to an abundance of shale and are typically poorly exposed. An exception is the Cerro Toro Formation of southern Chile.

A single channel-levee complex in the Cerro Silla syncline was studied in detail. Four main depositional facies are identified in the levee. These are blanket beds, lenticular beds, crevasse-fill, and mass movement facies. The major facies in the levee is composed of blanket beds that consist of thin-bedded sandstones and silty shales that are laterally continuous across the length of the outcrops. The change in thickness of the sandstone blanket beds was measured across the length of one outcrop. Thicker sandstone blanket beds (> 2”) thin at a higher initial rate than thinner blanket sandstone beds (≤ 2”) and are also more likely to pinch out entirely. Lenticular sandstone beds are common in the proximal levee outcrops and locally have a high sandstone to mudstone ratio but are prone to be laterally discontinuous over distances of a few hundred feet. The most laterally discontinuous sandstones occur as thick, relatively coarse-grained beds within the crevasses. Crevasse-fill deposits can potentially be recognized in core as thick-bedded sandstone that occurs above a debris flow or slump deposit. Erosional surfaces and mass movement deposits are most common in the proximal and lower portions of the levee. Erosional surfaces are draped by blanket beds and less common onlapping lenticular sandstone beds. Recognition of these types of erosional surfaces in seismic data or in core may be difficult because they are below seismic resolution and lack a diagnostic lithofacies fill.
UTILIZATION OF 3-D SEISMIC IN VISUALIZING AND REINTERPRETING AN UNSTABLE SHELF AREA AND ITS RELATIONSHIP TO TURBIDITE DEPOSITION DOWNDIP, OFFSHORE NIGERIA
Authors: KEAN ALLAN
Published: April 2012

Mobil’s largest 3D seismic survey undertaken to date lies offshore in the eastern portion of the Niger Delta. The geologic section of interest is located between 1.5–2.5 seconds. The seismic data quality is very good in the zone of interest. Previous interpretations of the area, based on 2D seismic defined the gross structural picture, and significant oil/gas fields were discovered based on these interpretations.

Seismically, the 3D coverage facilitated interpretation of all the data through the acquisition of closely spaced lines. The closely spaced seismic profiles used in conjunction with time slice views allowed for improved integration and visualization of the entire data set. Areas of instability were identified where large blocks of sediments appear to have been rotated and transported out and away from their original depositional locations. Areas where shelfal sand deposits become unstable are potential source areas for turbidile deposition. Missing section, up to several thousand feet in the Unam wells, is interpreted to have been transported (or redeposited) downdip, in west-east and north-south directions, from its original depositional location. Turbidite sands, interpreted as having been deposited as part of a channel-levee system in a Lowstand Systems Tract, were drilled approximately 20 km downdip. The genetic relationship of these younger turbidite sands to the older, shallow water beach sands was in question.

Upon first look analysis of the 3D seismic volume, a different structural interpretation was envisioned, than previously existed. The new structural setting was one of contrattional overprinting on the extensional framework. A shale diapir became a shale mass. In cross-section, a rollover structure was determined to be related to a concave-convex-concave fault bend and lateral contractional stresses. Both the Eku and Unam field areas fit into this newly visualized tectonic framework.
RELATING DEPOSITIONAL FACIES TO SEISMIC-SCALE STRATAL GEOMETRIES, UPPER JURASSIC GREAT VALLEY SEQUENCE, CALIFORNIA
Authors: LYONS KEVIN T.
Published: April 2012

Stratal patterns identified from low-altitude aerial photographs have been integrated with the results of depositional facies mapping to document the two-dimensional lithologic heterogeneity of the Upper Jurassic Great Valley Sequence of the northern Sacramento Valley, California. This turbidite complex comprises the following depositional elements: (1) debris flow units, (2) channels and channel complexes, (3) channel-overbank systems, and (4) depositional lobe successions.

Vertical facies associations indicate that early phases of deposition within the turbidite complex were strongly influenced by local and regional tectonic instability. The Paskenta fault zone appears to have exerted a significant control on sedimentation patterns during this time. The resulting disorganized association of facies consists of (1) thick, amalgamated debris flow deposits, (2) broad, shallow, conglomerate and sandstone-filled channels, and thick intervals of mud-rich strata.

Upper portions of the turbidite complex are characterized by a more orderly association of facies consisting of laterally continuous coarse-grained intervals separated by thick successions of thin-bedded strata. Coarse-grained depositional elements include (1) isolated, conglomerate-filled channels, (2) associations of coarse-grained channelized and fine-grained unchannelized units interpreted as channel complexes, and (3) intervals of tabular sandstone units interpreted as depositional lobe successions.

Fine-grained channel-overbank intervals contain widely scattered sandstone-filled channels and sand-rich overbank deposits, but consist primarily of monotonous successions of mud-rich interchannel deposits. Taken together the observed facies associations suggest that the Great Valley turbidite complex was deposited in a lower slope to base of slope setting.
SEQUENCE STRATIGRAPHY OF NEOGENE STRATA IN OFFSHORE NIGERIA
Authors: Pacht Jory A. , Bowen Bruce E. , Hall David J. , Rosen Rachel , Shaffer Bernard L. , Choudhury Abu
Published: April 2012

The Dahomey Basin, located along the western portion of the Nigerian continental margin, is underlain by continental and transitional crust. It exhibits stable to moderately unstable progradation and is characterized by a well-developed shelf-slope break. Systems tracts are similar to those described for other stable progradational margins. In contrast, the Niger Delta Complex, located off the central and eastern portions of the Nigerian coast, exhibits highly unstable progradation. The shelf-slope break is commonly not well-developed. Instead, a ramp, characterized by relatively uniform dip, is present. Large growth faults cut the ramp and define the shelf margin. Systems tracts are similar to those in deep-water Neogene strata of the offshore Gulf of Mexico.

The basin floor fan and slope fan depositional systems comprise the lower lowstand systems tract. Basin-floor fans in both areas are defined by a prominent reflection along their upper boundary. This reflection downlaps along the sequence boundary or abuts against the down thrown side of a growth fault surface. The slope fan contains channel-fill complexes characterized by chaotic bedding and less common large channel-fills, which exhibit concave-upward reflections. Most slope-f an strata exhibit discontinuous lo semi-continuous subparallel reflections. In the Dahomey Basin, slope fan deposits commonly pinch out at or near the shelf margin. In contrast, contemporaneous shallow-water facies are developed in the Niger Delta Complex. Deposition occurred from multiple point sources.

Large amplitude anomalies in the upper lowstand (prograding wedge) suggest thick sheet sands are present in the Niger Delta Complex. These sands occur in both shallow-water (interpreted as delta front facies) and deep-water environments (interpreted as shingled turbidites). Water depths are constrained in areas in which well control is present by benthic foraminifera. Transgressive and highstand systems tracts are commonly very thin.

Different exploration strategies are appropriate for each systems tract off both the western and central portions of the Nigerian Coast. The best plays off the central portion of the Nigerian coast are probably structural traps and combination structural and stratigraphic traps (this includes updip pinchouts), whereas hydrocarbons may occur in smaller pure structural to pure stratigraphic traps along the west coast of Nigeria.
INTERPRETING FORMATION MICROSCANNER LOG IMAGES OF GULF OF MEXICO PLIOCENE TURBIDITES BY COMPARISON WITH PENNSYLVANIAN TURBIDITE OUTCROPS, ARKANSAS
Authors: SLATT ROGER M. , JORDAN DOUGLAS W. , DAVIS ROBERT J.
Published: April 2012

Sedimentair features observed in canyon-fill and basin floor turbidites in the Pennsylvanian Jackfork Formation, Ouachita Mountains of Arkansas have been compared with what we interpret as identical features observed on Formation MicroScanner (mark of Schlumberger) images from offshore Louisiana Pliocene turbidites.

Small-scale features displayed in outcrop and on the Formation MicroScanner images include slumps, erosional surfaces, thin sand-shale interbeds, mud-lined depressions/scours, isolated sandstone clasts in shaley debris flow beds, remnant bedding in various stages of disruption owing to flowage, and load structures. On a larger scale, thin-and thick-bedded sandstone-shale intervals are recognized, which are probably laterally continuous for some distance.

Based upon the outcrop criteria, recognition of these features on Formation MicroScanner images can lead to an improved interpretation of the images with respect to Gulf of Mexico (and elsewhere) deep-water deposilional processes, facies and their three-dimensional geometry, relative reservoir quality, and lateral and vertical continuity of beds. This improved interpretation can be valuable in resolving reservoir iramagement, development drilling, and exploration issues.