bluuebunny/crossref_metadata_2025 huggingface dataset:
GeoFree BrandComms
Authors: Devasagayam P. Raj , Heuvel Dana A. VanDen
Published: June 2013

Marketing literature has established the strategic importance of building communities centered around strong brands—brand communities. Our research adds to the current understanding of brand communities by extending the notion of brand community being non-geographically bound. While prior research acknowledges this characteristic of brand community, it fails to, firstly, illustrate the strategic importance of such freedom, and secondly, provide directions for an operational, tactical, or strategic tool to truly build and sustain non-geographically bound brand communities. We refer to such communities as geographically free brand communities (GeoFree BrandComms). This research presents the conceptual underpinnings and characteristics of GeoFree BrandComms. Further, the use of Weblogs (Blogs) and related technologies such as video blogs, podcasts, and RSS as strategic tools in building GeoFreeBrandComms is explored. We then proceed to posit the applications of GeoFree BrandComms in Web-based marketing strategies that find their basis in strong brands and loyal customers.
Elucidating pheromone and host volatile components attractive to the spruce beetle, Dendroctonus rufipennis (Coleoptera: Curculionidae), in eastern Canada
Authors: Ryall K.L. , Silk P. , Thurston G.S. , Scarr T.A. , de Groot P.
Published: June 2013

Frontalin, seudenol, and a spruce terpene blend are key components of a lure for monitoring spruce beetle, Dendroctonus rufipennis (Kirby) (Coleoptera: Curculionidae: Scolytinae) in eastern Canada, catching the highest number of beetles in several field trials. The standard two-component commercial lure for this species, developed from populations in western North America and composed of 95%:5% (±)-α-pinene and frontalin, failed to elicit attraction to traps in Atlantic Canada; thus a series of trapping experiments were conducted to identify an improved combination of pheromone and host volatiles for this region. Analysis of volatiles from D. rufipennis collected from Newfoundland and Nova Scotia, Canada detected seudenol as an additional female-produced component. Laboratory analysis of the eastern host (Picea glauca (Moench) Voss; Pinaceae) detected the presence of 75%:25% (±)-α-pinene; however, a two-component lure comprised of 75%:25% (±)-α-pinene and frontalin caught no more beetles than an unbaited control. Frontalin and seudenol alone or spruce terpene blend and ethanol alone typically had among the lowest trap catches, but when combined they caught the highest numbers of D. rufipennis, supporting the hypothesis that host volatiles synergise attraction to pheromones. Our results highlight the importance of geographic variation in the response to pheromones and kairomones in this bark beetle.
Critical Role of the Tumor Suppressor Tuberous Sclerosis Complex 1 in Dendritic Cell Activation of CD4 T Cells by Promoting MHC Class II Expression via IRF4 and CIITA
Authors: Pan Hongjie , O’Brien Thomas F. , Wright Gabriela , Yang Jialong , Shin Jinwook , Wright Kenneth L. , Zhong Xiao-Ping
Published: June 2013

Dendritic cell (DC) maturation is characterized by upregulation of cell-surface MHC class II (MHC-II) and costimulatory molecules, and production of a variety of cytokines that can shape both innate and adaptive immunity. Paradoxically, transcription of the MHC-II genes, as well as its activator, CIITA, is rapidly silenced during DC maturation. The mechanisms that control CIITA/MHC-II expression and silencing have not been fully understood. We report in this article that the tumor suppressor tuberous sclerosis complex 1 (TSC1) is a critical regulator of DC function for both innate and adaptive immunity. Its deficiency in DCs results in increased mammalian target of rapamycin (mTOR) complex 1 but decreased mTORC2 signaling, altered cytokine production, impaired CIITA/MHC-II expression, and defective Ag presentation to CD4 T cells after TLR4 stimulation. We demonstrate further that IFN regulatory factor 4 can directly bind to CIITA promoters, and decreased IFN regulatory factor 4 expression is partially responsible for decreased CIITA/MHC-II expression in TSC1-deficient DCs. Moreover, we identify that CIITA/MHC-II silencing during DC maturation requires mTOR complex 1 activity. Together, our data reveal unexpected roles of TSC1/mTOR that control multifaceted functions of DCs.
β-Defensin 2 and 3 Promote the Uptake of Self or CpG DNA, Enhance IFN-α Production by Human Plasmacytoid Dendritic Cells, and Promote Inflammation
Authors: Tewary Poonam , de la Rosa Gonzalo , Sharma Neeraj , Rodriguez Luis G. , Tarasov Sergey G. , Howard O. M. Zack , Shirota Hidekazu , Steinhagen Folkert , Klinman Dennis M. , Yang De , Oppenheim Joost J.
Published: June 2013

Alarmins are a group of structurally diverse host defense antimicrobial peptides that are important immune activators. In this article, we present a novel role for two potent alarmins, human β-defensin 2 and 3 (HBD2 and 3), in promoting IFN-α production by human plasmacytoid dendritic cells. We demonstrate that HBD2 and 3 activate pDCs by enhancing the intracellular uptake of CpG and self DNA and promote DNA-induced IFN-α production in a TLR9-dependent manner. Both CpG and host DNA form aggregates that resemble DNA nets when combined with HBD2 and 3. Isothermal titration calorimetry studies to elucidate the nature of HBD3/CpG complexes demonstrate involvement of enthalpy-driven interactions, in addition to hydrophobic interactions, with the formation of complexes at a molar ratio of 2:1 defensin/CpG. The i.v. administration of HBD3/CpG complexes induced proinflammatory cytokines like IL-12, IFN-γ, IL-6, IFN-α, and IL-10 in serum, associated with an increased recruitment of APCs in the spleen. Subcutaneous injections of these complexes showed enhanced infiltration of inflammatory cells at the injection site, indicating a potential pathophysiological role for alarmin/DNA complexes in contributing to inflammation. Intraperitoneal immunization of HBD3/CpG complexes with OVA enhanced both cellular and humoral responses to OVA, compared with OVA/HBD3 or OVA/CPG alone, indicative of a much more potent adjuvant effect of the HBD3/CpG complexes. Thus, the ability of defensins to enhance cellular uptake of nucleic acids can lead to improved vaccine formulations by promoting their uptake by various cells, resulting in an enhanced immune response.
IL-4 Upregulates Igα and Igβ Protein, Resulting in Augmented IgM Maturation and B Cell Receptor–Triggered B Cell Activation
Authors: Guo Benchang , Rothstein Thomas L.
Published: June 2013

IL-4 is critical for optimal B cell activation and germinal center B cell expansion in T-dependent immune responses; however, the underlying mechanism remains elusive. In the current study, we found that primary B cells express little Igα and Igβ protein despite substantial levels of mRNA. IL-4 markedly upregulates Igα and Igβ protein expression that requires STAT6. Elevated Igα and Igβ protein form heterodimers that associate with IgM and significantly promote IgM maturation and surface IgM expression, resulting in amplified BCR-initiated signaling that is Lyn dependent. In vivo, we found that pregerminal center B cells express upregulated Igα, Igβ, and surface IgM expression, in conjunction with elevated BCR-triggered phosphorylated ERK ex vivo, that are dependent on IL-4 and reversed by in vivo administration of neutralizing anti–IL-4 Ab. Thus, this study elucidates a novel mechanism for cross-talk between the IL-4 and BCRs that programs enhancement of subsequent BCR signaling.
Erythrocyte-Binding Antigens of Plasmodium falciparum Are Targets of Human Inhibitory Antibodies and Function To Evade Naturally Acquired Immunity
Authors: Persson Kristina E. M. , Fowkes Freya J. I. , McCallum Fiona J. , Gicheru Nimmo , Reiling Linda , Richards Jack S. , Wilson Danny W. , Lopaticki Sash , Cowman Alan F. , Marsh Kevin , Beeson James G.
Published: June 2013

Abs that inhibit Plasmodium falciparum invasion of erythrocytes form an important component of human immunity against malaria, but key target Ags are largely unknown. Phenotypic variation by P. falciparum mediates the evasion of inhibitory Abs, contributing to the capacity of P. falciparum to cause repeat and chronic infections. However, Ags involved in mediating immune evasion have not been defined, and studies of the function of human Abs are limited. In this study, we used novel approaches to determine the importance of P. falciparum erythrocyte-binding Ags (EBAs), which are important invasion ligands, as targets of human invasion-inhibitory Abs and define their role in contributing to immune evasion through variation in function. We evaluated the invasion-inhibitory activity of acquired Abs from malaria-exposed children and adults from Kenya, using P. falciparum with disruption of genes encoding EBA140, EBA175, and EBA181, either individually or combined as EBA140/EBA175 or EBA175/EBA181 double knockouts. Our findings provide important new evidence that variation in the expression and function of the EBAs plays an important role in evasion of acquired Abs and that a substantial amount of phenotypic diversity results from variation in expression of different EBAs that contributes to immune evasion by P. falciparum. All three EBAs were identified as important targets of naturally acquired inhibitory Abs demonstrated by differential inhibition of parental parasites greater than EBA knockout lines. This knowledge will help to advance malaria vaccine development and suggests that multiple invasion ligands need to be targeted to overcome the capacity of P. falciparum for immune evasion.
Identification and Prioritization of Merozoite Antigens as Targets of Protective Human Immunity to Plasmodium falciparum Malaria for Vaccine and Biomarker Development
Authors: Richards Jack S. , Arumugam Thangavelu U. , Reiling Linda , Healer Julie , Hodder Anthony N. , Fowkes Freya J. I. , Cross Nadia , Langer Christine , Takeo Satoru , Uboldi Alex D. , Thompson Jennifer K. , Gilson Paul R. , Coppel Ross L. , Siba Peter M. , King Christopher L. , Torii Motomi , Chitnis Chetan E. , Narum David L. , Mueller Ivo , Crabb Brendan S. , Cowman Alan F. , Tsuboi Takafumi , Beeson James G.
Published: June 2013

The development of effective malaria vaccines and immune biomarkers of malaria is a high priority for malaria control and elimination. Ags expressed by merozoites of Plasmodium falciparum are likely to be important targets of human immunity and are promising vaccine candidates, but very few Ags have been studied. We developed an approach to assess Ab responses to a comprehensive repertoire of merozoite proteins and investigate whether they are targets of protective Abs. We expressed 91 recombinant proteins, located on the merozoite surface or within invasion organelles, and screened them for quality and reactivity to human Abs. Subsequently, Abs to 46 proteins were studied in a longitudinal cohort of 206 Papua New Guinean children to define Ab acquisition and associations with protective immunity. Ab responses were higher among older children and those with active parasitemia. High-level Ab responses to rhoptry and microneme proteins that function in erythrocyte invasion were identified as being most strongly associated with protective immunity compared with other Ags. Additionally, Abs to new or understudied Ags were more strongly associated with protection than were Abs to current vaccine candidates that have progressed to phase 1 or 2 vaccine trials. Combinations of Ab responses were identified that were more strongly associated with protective immunity than responses to their single-Ag components. This study identifies Ags that are likely to be key targets of protective human immunity and facilitates the prioritization of Ags for further evaluation as vaccine candidates and/or for use as biomarkers of immunity in malaria surveillance and control.
A Transgenic TCR Directs the Development of IL-4+ and PLZF+ Innate CD4 T Cells
Authors: Zhu Lingqiao , Qiao Yu , Choi Esther S. , Das Joy , Sant’Angelo Derek B. , Chang Cheong-Hee
Published: June 2013

MHC class II–expressing thymocytes can efficiently mediate positive selection of CD4 T cells in mice. Thymocyte-selected CD4 (T-CD4) T cells have an innate-like phenotype similar to invariant NKT cells. To investigate the development and function of T-CD4 T cells in-depth, we cloned TCR genes from T-CD4 T cells and generated transgenic mice. Remarkably, positive selection of T-CD4 TCR transgenic (T3) thymocytes occurred more efficiently when MHC class II was expressed by thymocytes than by thymic epithelial cells. Similar to polyclonal T-CD4 T cells and also invariant NKT cells, T3 CD4 T cell development is controlled by signaling lymphocyte activation molecule/signaling lymphocyte activation molecule–associated protein signaling, and the cells expressed both IL-4 and promyelocytic leukemia zinc finger (PLZF). Surprisingly, the selected T3 CD4 T cells were heterogeneous in that only half expressed IL-4 and only half expressed PLZF. IL-4– and PLZF-expressing cells were first found at the double-positive cell stage. Thus, the expression of IL-4 and PLZF seems to be determined by an unidentified event that occurs postselection and is not solely dependent on TCR specificity or the selection process, per se. Taken together, our data show for the first time, to our knowledge, that the TCR specificity regulates but does not determine the development of innate CD4 T cells by thymocytes.
The significance of buried valleys to groundwater systems in the Oak Ridges Moraine region, Ontario: extent, architecture, sedimentary facies and origin of valley settings in the ORM region
Authors: Sharpe D R , Russell H A J , Pugin A
Published: June 2013

The fieldtrip traverses the glaciated landscape of southeastern Ontario from the Niagara Escarpment to the Ottawa Valley. The focus of the trip is on the glacial geology of a continental basin and tunnel valleys hosted within the glacial stratigraphy of the Oak
Ridges Moraine region. Using digital elevation models, and detailed geological mapping, a system of anabraching valleys has been classified on the basis of length, width and depth. The valleys have been traced beneath the Oak Ridges Moraine using high-quality shallow reflection seismic and
continuous borehole data. The trip presents a suite of subsurface data with outcrop sedimentology in support of meltwater process models and depositional environments. Process models are considered to relate to regional subglacial landscapes and are used to explain the origin of regional
unconformities and the formation of tunnel valleys. Depositional process models, such as the jet-efflux model, will be discussed to interpret key sedimentary facies and evidence for hydraulic jumps where rapid flow meets standing bodies of water.
The trip starts at the famous Scaborough Bluffs on Lake Ontario, with a discussion of the regional glacial stratigraphy and units beneath the late glacial Newmarket Till, truncated by regional unconformities. Subsequent stops on day one highlight inter-valley sediments beneath the Oak Ridges Moraine
and outcrop sediments of the ORM interpreted within a subaqueous fan setting. Day two reviews the surface expression of tunnel valleys, seismic mapping of buried valleys and regional meltwater concepts for tunnel valley formation. It will also visit an outstanding outcrop site that reveals
depositional elements (jet- model and hydraulic jump processes) beyond the inferred tunnel channel depression. On day three, the trip traverses the length of the Oak Ridges Moraine and beyond, to view tunnel valleys, sediments of the ORM, drumlin fields and eskers. The final day of the trip offers a
hands-on inspection of continuous cores, highlighting the sedimentary facies, downhole geophysics and geochemistry of key basin stratigraphic units that frame channel complexes.
The principal objective of the fieldtrip is to assess a 200 m thick glacial basin with tunnel valleys and fills with respect to its reservoir analogue potential for similar Paleozoic glaciogenic deposits. Such deposits represent important hydrocarbon reservoirs in North Africa and the Middle East.
The secondary trip objective is to demonstrate the field support for a range of methods and process-based sedimentary models for tunnel valley formation and deposition of related channel-fill facies.
Aqueous geochemistry of the Englishman River Watershed, Parksville, British Columbia for use in assessment of potential surface water-groundwater interaction
Authors: Provencher S K , Mayer B , Grasby S E
Published: June 2013

The population in the Englishman River Watershed (ERW) in Parksville, BC is over 50% reliant on groundwater. Increasing development pressures have raised local, provincial and federal government concerns over sustainability of water resources. The Englishman
River is viewed as a significant water source to support future growth and economic development. Managing long-term sustainable use of water resources of this watershed is imperative for both ecologic health and economic prosperity. As water demand pressures grow, sustainable water management
requires knowledge of the degree of surface water-groundwater (SW/GW) interaction within a watershed. Geochemical methods can provide valuable information on seasonal aquifer contribution and SW/GW interactions. Developing geochemical tools that can place constraints on these complex systems will
aid development of hydrogeological models, which can be used to support decision makers in water allocation.
This open file provides initial geochemical results from a groundwater well and river sampling program in the Englishman River watershed carried out in 2010-2011.
Biomedical laboratory science education: standardising teaching content in resource-limited countries
Authors: Arneson Wendy , Robinson Cathy , Nyary Bryan
Published: June 2013

Background: There is a worldwide shortage of qualified laboratory personnel to provide adequate testing for the detection and monitoring of diseases. In an effort to increase laboratory capacity in developing countries, new skills have been introduced into laboratory services. Curriculum revision with a focus on good laboratory practice is an important aspect of supplying entry-level graduates with the competencies needed to meet the current needs.Objectives: Gaps in application and problem-solving competencies of newly graduated laboratory personnel were discovered in Ethiopia, Tanzania and Kenya. New medical laboratory teaching content was developed in Ethiopia, Tanzania and Kenya using national instructors, tutors, and experts and consulting medical laboratory educators from the United States of America (USA).Method: Workshops were held in Ethiopia to create standardised biomedical laboratory science (BMLS) lessons based on recently-revised course objectives with an emphasis on application of skills. In Tanzania, course-module teaching guides with objectives were developed based on established competency outcomes and tasks. In Kenya, example interactive presentations and lesson plans were developed by the USA medical laboratory educators prior to the workshop to serve as resources and templates for the development of lessons within the country itself.Results: The new teaching materials were implemented and faculty, students and other stakeholders reported successful outcomes.Conclusions: These approaches to updating curricula may be helpful as biomedical laboratory schools in other countries address gaps in the competencies of entry-level graduates.
Inadvertent chest tube insertion in congenital cystic adenomatoid malformation and congenital lobar emphysema-highlighting an important problem
Authors: Prabhu Shailesh M , Choudhury Subhasis Roy , Solanki Ravi S , Shetty Gurucharan S , Agarwala Surender kumar
Published: June 2013

Background: Chest tube insertion in congenital cystic lung lesions is an important problem in children with acute respiratory distress having a cystic lucent lesion on chest radiograph. Objective: To evaluate the imaging findings and complications in cases of congenital cystic lung lesions with chest tube insertion and suggest the role of appropriate imaging for management of these patients. Materials and Methods: Chest radiographs and CT scans of children with congenital cystic lung lesions who had inadvertent chest tube insertion preoperatively were retrospectively reviewed for imaging appearances and complications. Results: Fifteen patients comprising 10 cases of congenital cystic adenomatoid malformation (CCAM) and 5 cases of congenital lobar emphysema (CLE) were included. Majority of the cases were infants. CCAM was misdiagnosed as complicated pneumatocele (n = 5) and pneumothorax (n = 5), while CLE was misdiagnosed as tension pneumothorax (n = 5) on the chest radiograph findings. Final diagnosis was made on CT and operative findings with histopathology. Complications noted were pneumothorax, hydropneumothorax, and infection in cases of CCAM, and change in imaging appearance and pneumothorax in cases of CLE. Conclusion: Chest tube insertion in congenital cystic lesions increases the rate of associated complications. Chest CT has a definite role in early diagnosis and deciding appropriate management in these cases.
Dendriform pulmonary ossification: Report of two cases
Authors: Jamjoom Lamia , Meziane Moulay , Renapurkar Rahul D
Published: June 2013

Dendriform pulmonary ossification is a rare form of diffuse pulmonary ossification that is usually detected incidentally on chest radiographs or chest computed tomography (CT) imaging. In this article, we present two patients who were incidentally found to have dendriform pulmonary ossification on chest imaging. The article will present the history and imaging findings of these two cases and then review the clinical, histological, and radiographic manifestations of dendriform pulmonary ossification.
Role of quantitative pharmacokinetic parameter (transfer constant: Ktrans) in the characterization of breast lesions on MRI
Authors: Amarnath Jena , Sangeeta Taneja , Mehta Shashi Bhushan
Published: June 2013

Background: The semi-quantitative analysis of the time-intensity curves in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has a limited specificity due to overlapping enhancement patterns after gadolinium administration. With the advances in technology and faster sequences, imaging of the entire breast can be done in a few seconds, which allows measuring the transit of contrast (transfer constant: Ktrans) through the vascular bed at capillary level that reflects quantitative measure of porosity/permeability of tumor vessels. Aim: Our study aims to evaluate the pharmacokinetic parameter Ktrans for enhancing breast lesions and correlate it with histopathology, and assess accuracy, sensitivity, and specificity of this parameter in discriminating benign and malignant breast lesions. Materials and Methods: One hundred and fifty-one women with 216 histologically proved enhancing breast lesions underwent high temporal resolution DCE-MRI for the early dynamic analysis for calculation of pharmacokinetic parameters (Ktrans) using standard two compartment model. The calculated values of Ktrans were correlated with histopathology to calculate the sensitivity, specificity, and accuracy. Results: Receiver operating characteristic (ROC) curve analysis revealed a mean Ktrans value of 0.56, which reliably distinguished benign and malignant breast lesions with a sensitivity of 91.1% and specificity of 90.3% with an overall accuracy of 89.3%. The area under curve (AUC) was 0.907. Conclusion: Ktrans is a reliable quantitative parameter for characterizing benign and malignant lesions in routine DCE-MRI of breasts.
Tuberculosis of the genitourinary system-Urinary tract tuberculosis: Renal tuberculosis-Part I
Authors: Merchant Suleman , Bharati Alpa , Merchant Neesha
Published: June 2013

Tuberculosis (TB) remains a worldwide scourge and its incidence appears to be increasing due to various factors, such as the spread of human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS). The insidious onset and non-specific constitutional symptoms of genitourinary tuberculosis (GUTB) often lead to delayed diagnosis and rapid progression to a non-functioning kidney. Due to hematogenous dissemination of TB, there is a potential risk of involvement of the contralateral kidney too. Imaging plays an important role in the making of a timely diagnosis and in the planning of treatment, and thus helps to avoid complications such as renal failure. Imaging of GUTB still remains a challenge, mainly on account of the dearth of literature, especially related to the use of the newer modalities such as magnetic resonance imaging (MRI). This two-part article is a comprehensive review of the epidemiology, pathophysiology, and imaging findings in renal TB. Various imaging features of GUTB are outlined, from the pathognomonic lobar calcification on plain film, to finer early changes such as loss of calyceal sharpness and papillary necrosis on intravenous urography (IVU); to uneven caliectasis and urothelial thickening, in the absence of renal pelvic dilatation, as well as the hitherto unreported ′lobar caseation′ on ultrasonography (USG). Well-known complications of GUTB such as sinus tracts, fistulae and amyloidosis are described, along with the relatively less well-known complications such as tuberculous interstitial nephritis (TIN), which may remain hidden because of its ′culture negative′ nature and thus lead to renal failure. The second part of the article reviews the computed tomography (CT) and MRI features of GUTB and touches upon future imaging techniques along with imaging of TB in transplant recipients and in immunocompromised patients.
Congenital duplication of mastoid segment of facial nerve: A rare case report
Authors: Jakkani Ravi Kanth , KI Ragavendra , Karnawat Aruna , Vittal R , Kumar Anjani D
Published: June 2013

Congenital duplication of facial nerve is a very rare anomaly commonly associated with inner and middle ear anomalies. There can be duplication of mastoid, tympanic, or labyrinthine segments. We describe duplication of mastoid segment of facial nerve in a young female who also showed middle ear anomalies and external auditory canal atresia.
Comparing percutaneous primary and secondary biliary stenting for malignant biliary obstruction: A retrospective clinical analysis
Authors: Chatzis Nikolaos , Pfiffner Roger , Glenck Michael , Stolzmann Paul , Pfammatter Thomas , Sharma Pankaj
Published: June 2013

Purpose: Percutaneous transhepatic primary biliary stenting (PS) is an alternative to the widely used staged procedure (secondary biliary stenting, SS) for treating obstructive jaundice in cancer patients. To evaluate the efficacy and safety of PS and SS, a retrospective analysis was carried out. Materials and Methods: The percutaneous biliary stenting procedures performed between January 2000 and December 2007 at one hepatobiliary center were retrospectively analyzed, comparing the technical success rates, complications, and length of hospitalization of the two procedures. Of 61 patients (mean age 65.5 ± 13.1 years; range 31.1-92.7 years) suffering from obstructive jaundice caused by primary or metastatic tumors, 30 received PS and 31 received SS. The groups were comparable in the anatomical level of the obstruction, stent configuration, or the concurrent presence of cholangitis. Placement of metallic stents required one session for patients in the PS group and an average of 2.6 ± 1.1 sessions for patients in the SS group. Results: The overall technical success rate was 98.4% with 1 (1/61) failed approach to transcend the occlusion in the SS group. The rate of minor complications was 10% in the PS group and 6.5% in the SS group. The corresponding rates of major complications were 23.3% and 54.8%, respectively. SS patients had a higher rate of complications in general ( P < 0.05), as well as a higher rate of severe complications in particular ( P < 0.05). Procedural mortality was 0% for both the groups. The mean overall length of hospitalization was 7.7 ± 9.6 days for PS and 20.6 ± 19.6 days for SS ( P < 0.001). Conclusion: Primary percutaneous biliary stenting of malignant biliary obstructions is as efficacious and safer than a staged procedure with secondary stenting. By virtue of requiring shorter hospital stays, primary stenting is likely to be more cost-effective.
MRI enterography with divided dose oral preparation: Effect on bowel distension and diagnostic quality
Authors: Sinha Rakesh , Rawat Sudarshan
Published: June 2013

Aim: To assess the impact of an extended oral preparation magnetic resonance (MR) enterography protocol on bowel distension, timing of imaging, and the quality of diagnostic images. Materials and Methods: An analysis of 52 patients who underwent divided oral preparation and 39 patients who underwent standard preparation for MR enterography examination was done. Distension was assessed by measuring the transverse diameters of the jejunum, ileum, and the ileocecal region. Diagnostic quality of the examination was assessed subjectively by two radiologists and graded as poor, diagnostic, and excellent (Grades 1-3). Correlation between bowel diameter and diagnostic quality was assessed using regression analysis. Results: The mean diameters of the jejunum, ileum, and colon in patients who underwent divided preparation were 1.90 ± 0.47, 2.14 ± 0.41, and 4.27 ± 0.96 cm, respectively, and the mean diameters in patients who underwent standard preparation were 1.46 ± 0.47, 2.02 ± 0.47, and 4.45 ± 0.90 cm, respectively. A total of 96.6% of patients on divided dose had diagnostic distension of the bowel (Grades 2 and 3). A total of 87.9% of the patients on standard dose had diagnostic distension of the bowel (Grades 2 and 3). A greater number of patients who underwent divided preparation had diagnostic quality examinations compared to those given standard preparation (96.6% vs. 87.9%). A greater number of patients who underwent divided preparation had Grade 3 quality examinations compared to those on standard preparation (75.5% vs. 68.5%). There was significant difference between diagnostic (Grades 2 and 3) and optimal grades (Grade 3) of the jejunal diameters in patients having divided or standard preparation (89.7% vs. 66.6%, P < 0.05; 40.8% vs. 25%, P < 0.05, respectively). Linear regression showed a positive correlation between increasing bowel diameter and diagnostic grade of the examination (ρ = 0.76). Conclusion: Using an extended oral preparation with divided dose resulted in the majority of patients being scanned in a single visit to the MRI suite. Dividing the oral contrast into aliquots can promote uniform distension of the entire small bowel and provide better bowel distension and improve the diagnostic quality.
"Flow comp off": An easy technique to confirm CSF flow within syrinx and aqueduct
Authors: Sen Anitha
Published: June 2013

Flow compensation, a gradient pulse used for artifact reduction, often used to suppress cerebrospinal fluid (CSF) flow artifacts in spinal magnetic resonance imaging (MRI), can be switched off to make the CSF flow voids within syrinx (syringomyelia) and within aqueduct [normal pressure hydrocephalus (NPH)] more obvious (thus confirming CSF flow). It is a simple method which does not require much time or expertise.
Coping in a calamity: Radiology during the cloudburst at Leh
Authors: Sen Debraj
Published: June 2013

The service hospital at Leh is a multispeciality hospital situated at an altitude of 11000 feet above mean sea level. On the nights of 4 and 5 Aug 2010, Leh was struck by a cloudburst leading to mudslides and consequently extensive damage to life and property. Being the only functional hospital, over a period of about 48 hours, 331 casualties were received. 549 casualties were received over the week with 108 admissions, 16 major surgeries and 138 minor surgeries. 178 radiographs, 17 CT scans and 09 ultrasound-colour Doppler examinations were performed on an urgent basis over 48 hours apart from the routine radiological investigations. Apart from chronicling the event, we hope that sharing the unique experience of the Radiology Department in dealing with the large influx of patients would provide an insight into the role of Radiology during the disaster and help in planning and developing management protocols during other calamities.
Biochemical Characteristics of Organic Matter in a Guano Concretion of Late Miocene or Pliocene Age from Manchester Parish in Jamaica
Authors: Spence Adrian , Hanson Richard E. , Johnson Toni , Robinson Claion , Annells Richard N.
Published: June 2013

The biogeochemical fate of organic matter (OM) entering soils is an important issue that must be examined to better understand its roles in nitrogen cycling and as a natural modulator of soil-atmospheric carbon fluxes. Despite these critical roles, there are uncertainties in estimating the contribution of this feedback mechanism due in part to a lack of molecular-level information regarding the origin and labile and refractory inventories of OM in soils. In this study, we used a multi-analytical approach to determine molecular-level information for the occurrence and stabilization of OM in a bird guano concretion of the Late Miocene or Pliocene age in Jamaica. We determined the specific organic structures persisting in the concretion and the possible contribution of fossil organic matter to the OM pool in modern environments. Our results indicate that aliphatic species, presumably of a highly polymethylenic nature [(CH2) n], may significantly contribute to the stable soil-C pool. Although not as significant, proteins and carbohydrates were also enriched in the sample, further suggesting that fossil organic matter may contribute to carbon and nitrogen pools in present day soil organic matter.
ZL-amenability Constants of Finite Groups with Two Character Degrees
Authors: Alaghmandan Mahmood , Choi Yemon , Samei Ebrahim
Published: June 2013

We calculate the exact amenability constant of the centre of ℓ1(G) when G is a finite group and is either dihedral, extraspecial, or Frobenius with abelian complement and kernel. This is done using a formula that applies to all finite groups with two character degrees. In passing, we answer in the negative a question raised in work of the third author with Azimifard and Spronk.
Experimental Study of Sour Top-of-the-Line Corrosion Using a Novel Experimental Setup
Authors: Singer M. , Al-Khamis J. , Nešić S.
Published: June 2013

Top-of-the-line corrosion (TLC) is a potential issue for carbon steel pipelines transporting natural gas. This type of corrosion is driven mostly by the gradient of temperature between the warm produced fluids and the outside environment, but also is affected strongly by the presence of corrosive species such as carbon dioxide (CO2), hydrogen sulfide (H2S), and organic acids. This paper presents an assessment of the corrosion risk of a specific sour offshore development: the Karan gas field (Arabian Gulf, Saudia Arabia). The study was performed through laboratory experiments in a large-scale flow loop as well as in a specially designed autoclave equipped for corrosion studies under dewing conditions. Corrosion rates were obtained using the weight-loss method and the surface layer was analyzed with x-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). The TLC rate was found to be low under all conditions tested, and no indications of localized corrosion were observed. Mackinawite, cubic iron sulfide, and troilite (stoichiometric pyrrhotite) were identified in the corrosion product layer.
Estimation of volatile organic compound emissions for Europe using data assimilation
Authors: Koohkan M. R. , Bocquet M. , Roustan Y. , Kim Y. , Seigneur C.
Published: June 2013

Abstract. The emissions of non-methane volatile organic compounds (VOCs) over western Europe for the year 2005 are estimated via inverse modelling by assimilation of in situ observations of concentration and then subsequently compared to a standard emission inventory. The study focuses on 15 VOC species: five aromatics, six alkanes, two alkenes, one alkyne and one biogenic diene. The inversion relies on a validated fast adjoint of the chemical transport model used to simulate the fate and transport of these VOCs. The assimilated ground-based measurements over Europe are provided by the European Monitoring and Evaluation Programme (EMEP) network. The background emission errors and the prior observational errors are estimated by maximum-likelihood approaches. The positivity assumption on the VOC emission fluxes is pivotal for a successful inversion, and this maximum-likelihood approach consistently accounts for the positivity of the fluxes. For most species, the retrieved emissions lead to a significant reduction of the bias, which underlines the misfit between the standard inventories and the observed concentrations. The results are validated through a forecast test and a cross-validation test. An estimation of the posterior uncertainty is also provided. It is shown that the statistically consistent non-Gaussian approach based on a reliable estimation of the errors offers the best performance. The efficiency in correcting the inventory depends on the lifetime of the VOCs and the accuracy of the boundary conditions. In particular, it is shown that the use of in situ observations using a sparse monitoring network to estimate emissions of isoprene is inadequate because its short chemical lifetime significantly limits the spatial radius of influence of the monitoring data. For species with a longer lifetime (a few days), successful, albeit partial, emission corrections can reach regions hundreds of kilometres away from the stations. Domain-wide corrections of the emission inventories of some VOCs are significant, with underestimations of the order of a factor of 2 for propane, ethane, ethylene and acetylene.
A functional group oxidation model (FGOM) for SOA formation and aging
Authors: Zhang X. , Seinfeld J. H.
Published: June 2013

Abstract. Secondary organic aerosol (SOA) formation from a volatile organic compound (VOC) involves multiple generations of oxidation that include functionalization and fragmentation of the parent carbon backbone and likely particle-phase oxidation and/or accretion reactions. Despite the typical complexity of the detailed molecular mechanism of SOA formation and aging, a relatively small number of functional groups characterize the oxidized molecules that constitute SOA. Given the carbon number and set of functional groups, the volatility of the molecule can be estimated. We present here a functional group oxidation model (FGOM) that represents the process of SOA formation and aging. The FGOM contains a set of parameters that are to be determined by fitting of the model to laboratory chamber data: total organic aerosol concentration, and O : C and H : C atomic ratios. The sensitivity of the model prediction to variation of the adjustable parameters allows one to assess the relative importance of various pathways involved in SOA formation. An analysis of SOA formation from the high- and low-NOx photooxidation of four C12 alkanes (n-dodecane, 2-methylundecane, hexylcyclohexane, and cyclododecane) using the FGOM is presented, and comparison with the statistical oxidation model (SOM) of Cappa et al. (2013) is discussed.
Long-term nitrogen addition decreases carbon leaching in a nitrogen-rich forest ecosystem
Authors: Lu X. , Gilliam F. S. , Yu G. , Li L. , Mao Q. , Chen H. , Mo J.
Published: June 2013

Abstract. Dissolved organic carbon (DOC) plays a critical role in the carbon (C) cycle of forest soils, and has been recently connected with global increases in nitrogen (N) deposition. Most studies on effects of elevated N deposition on DOC have been carried out in N-limited temperate regions, with far fewer data available from N-rich ecosystems, especially in the context of chronically elevated N deposition. Furthermore, mechanisms for excess N-induced changes of DOC dynamics have been suggested to be different between the two kinds of ecosystems, because of the different ecosystem N status. The purpose of this study was to experimentally examine how long-term N addition affects DOC dynamics below the primary rooting zones (the upper 20 cm soils) in typically N-rich lowland tropical forests. We have a primary assumption that long-term continuous N addition minimally affects DOC concentrations and effluxes in N-rich tropical forests. Experimental N addition was administered at the following levels: 0, 50, 100 and 150 kg N ha−1 yr−1, respectively. Results showed that seven years of N addition significantly decreased DOC concentrations in soil solution, and chemo-physical controls (solution acidity change and soil sorption) rather than biological controls may mainly account for the decreases, in contrast to other forests. We further found that N addition greatly decreased annual DOC effluxes from the primary rooting zone and increased water-extractable DOC in soils. Our results suggest that long-term N deposition could increase soil C sequestration in the upper soils by decreasing DOC efflux from that layer in N-rich ecosystems, a novel mechanism for continued accumulation of soil C in old-growth forests.
Responses of soil respiration and its temperature/moisture sensitivity to precipitation in three subtropical forests in southern China
Authors: Jiang H. , Deng Q. , Zhou G. , Hui D. , Zhang D. , Liu S. , Chu G. , Li J.
Published: June 2013

Abstract. Both long-term observation data and model simulations suggest an increasing chance of serious drought in the dry season and extreme flood in the wet season in southern China, yet little is known about how changes in precipitation pattern will affect soil respiration in the region. We conducted a field experiment to study the responses of soil respiration to precipitation manipulations – precipitation exclusion to mimic drought, double precipitation to simulate flood, and ambient precipitation as control (abbr. EP, DP and AP, respectively) – in three subtropical forests in southern China. The three forest sites include Masson pine forest (PF), coniferous and broad-leaved mixed forest (MF) and monsoon evergreen broad-leaved forest (BF). Our observations showed that altered precipitation strongly influenced soil respiration, not only through the well-known direct effects of soil moisture on plant and microbial activities, but also by modification of both moisture and temperature sensitivity of soil respiration. In the dry season, soil respiration and its temperature sensitivity, as well as fine root and soil microbial biomass, showed rising trends with precipitation increases in the three forest sites. Contrarily, the moisture sensitivity of soil respiration decreased with precipitation increases. In the wet season, different treatments showed different effects in three forest sites. The EP treatment decreased fine root biomass, soil microbial biomass, soil respiration and its temperature sensitivity, but enhanced soil moisture sensitivity in all three forest sites. The DP treatment significantly increased soil respiration, fine root and soil microbial biomass in the PF only, and no significant change was found for the soil temperature sensitivity. However, the DP treatment in the MF and BF reduced soil temperature sensitivity significantly in the wet season. Our results indicated that soil respiration would decrease in the three subtropical forests if soil moisture continues to decrease in the future. More rainfall in the wet season could have limited effect on the response of soil respiration to the rising of temperature in the BF and MF.
A reduced fraction of plant N derived from atmospheric N (%Ndfa) and reduced rhizobial nifH gene numbers indicate a lower capacity for nitrogen fixation in nodules of white clover exposed to long-term CO2 enrichment
Authors: Watanabe T. , Bowatte S. , Newton P. C. D.
Published: June 2013

Abstract. Using the δ15N natural abundance method, we found that the fraction of nitrogen derived from atmospheric N (%Ndfa) in field grown white clover (Trifolium repens L.) plants was significantly lower (72.0% vs. 89.5%, p = 0.047 in a grassland exposed to elevated CO2 for 13 yr using Free Air Carbon Dioxide Enrichment (FACE). Twelve months later we conducted an experiment to investigate the reasons behind the reduced N fixation. We took cuttings from white clover plants growing in the FACE and established individual plants in a glasshouse using soil from the appropriate ambient or elevated CO2 treatments. The established plants were then transplanted back into their "rings of origin" and sampled over a 6 week period. We used molecular ecological analyses targeting nifH genes and transcripts of rhizobia in symbiosis with white clover (Trifolium repens L.) to understand the potential mechanisms. Shoot biomass was significantly lower in eCO2 but there was no difference in nodule number or mass per plant. The numbers of nifH genes and gene transcripts per nodule were significantly reduced under eCO2 but the ratio of gene to transcript number and the strains of rhizobia present were the same in both treatments. We conclude that the capacity for biological nitrogen fixation was reduced by eCO2 in white clover and was related to the reduced rhizobia numbers in nodules. We discuss the finding of reduced gene number in relation to factors controlling bacteroid DNA amount which may imply an influence of nitrogen as well as phosphorus.
Implementation of dynamic crop growth processes into a land surface model: evaluation of energy, water and carbon fluxes under corn and soybean rotation
Authors: Song Y. , Jain A. K. , McIsaac G. F.
Published: June 2013

Abstract. Worldwide expansion of agriculture is impacting Earth's climate by altering the carbon, water and energy fluxes, but climate in turn is impacting crop production. To study this two-way interaction and its impact on seasonal dynamics of carbon, water and energy fluxes, we implemented dynamic crop growth processes into a land surface model, the Integrated Science Assessment Model (ISAM). In particular, we implement crop specific phenology schemes, which account for light, water, and nutrient stresses while allocating the assimilated carbon to leaf, root, stem and grain pools; dynamic vegetation structure growth, which better simulate the LAI and canopy height; dynamic root distribution processes in the soil layers, which better simulate the root response of soil water uptake and transpiration; and litter fall due to fresh and old dead leaves to better represent the water and energy interception by both stem and brown leaves of the canopy during leaf senescence. Observational data for LAI, above and below ground biomass, and carbon, water and energy fluxes were compiled from two Ameri-Flux sites, Mead, NE and Bondville, IL, to calibrate and evaluate the model performance under corn (C4)-soybean (C3) rotation system over the period 2001–2004. The calibrated model was able to capture the diurnal and seasonal patterns of carbon assimilation, water and energy fluxes under the corn-soybean rotation system at these two sites. Specifically, the calculated GPP, net radiation fluxes at the top of canopy and latent heat fluxes compared well with observations. The largest bias in model results is in sensible heat flux (H) for corn and soybean at both sites. With dynamic carbon allocation and root distribution processes, model simulated GPP and latent heat flux (LH) were in much better agreement with observation data than for the without dynamic case. Modeled latent heat improved by 12–27% during the growing season at both sites, leading to the improvement in modeled GPP by 13–61% compared to the without dynamic case.