bluuebunny/crossref_metadata_2025 huggingface dataset:
Regrowth Dynamics of ‘Tifton 85’ Bermudagrass as Affected by Nitrogen Fertilization
Authors: Alderman PD. , Boote KJ. , Sollenberger LE.
Published: June 2011

‘Tifton 85’ bermudagrass (Cynodon spp.) has been widely adopted as a forage and hay crop and is being considered as a cellulosic ethanol feedstock. The objective of this study was to evaluate the effects of N fertilization rate on Tifton 85 regrowth dynamics. A field study was conducted near Gainesville, FL, on established Tifton 85 in 2006 and 2007. The treatments were N rates of 0, 45, 90, and 135 kg N ha−1 regrowth period−1. Tissue mass, leaf:stem ratio, and tiller number and mass were measured weekly during 28‐d regrowth periods. Leaf mass followed logistic time trends with the upper asymptote varying between 50 and 225 g m−2 depending on N rate and season (summer and autumn). Stem mass lagged behind leaf mass for 7 to 14 d, subsequently following linear or quadratic time trends to reach between 75 and 300 g m−2 by 28 d. Increasing N rate from 0 to 135 kg ha−1 period−1 increased tiller mass at 28 d from 1.5 to 3 g tiller−1 in summer and 1 to 1.5 g tiller−1 in autumn. Leaf:stem ratio increased to 1.0 within 14 to 21 d, followed by a subsequent decrease. Rhizome and root mass were not affected by N fertilization. Increasing N rate primarily affected mass and proportion of above‐ground plant parts, with little effect on mass of below‐ground parts. Nitrogen nutrition index values were similar whether calculated from samples taken to a 10‐cm stubble height or from samples taken to the soil surface. Regrowth was not enhanced by N rate beyond 90 kg N ha−1 regrowth period−1.
Soybean Plastidal Omega‐3 Fatty Acid Desaturase Genes GmFAD7 and GmFAD8: Structure and Expression
Authors: Upchurch Robert G. , Ramirez Martha E.
Published: June 2011

We characterized soybean [Glycine max (L.) Merr.] FAD7 and FAD8 gene structure and expression responses to temperature and pathogen stress to compare and contrast these features to those reported for higher plant plastidal omega‐3 (ω‐3) desaturases. We found that the genomic structure and deduced amino acid sequence of soybean FAD7 and FAD8 are similar to other higher plant plastidal ω‐3 desaturases: eight exons and seven introns, predicted proteins of 453 amino acid residues containing three conserved histidine motifs, amino terminal chloroplast transit peptides, and molecular masses of 51.3 and 51.4 kDa, respectively. GmFAD7 has 76% amino acid sequence identity to GmFAD8. Two complete copies of GmFAD7, one on chromosome 18 and one on chromosome 7, and two complete copies of GmFAD8, one on chromosome 3 and one on chromosome 1 of the ‘Williams 82’ soybean genome, were found with strong sequence similarity to GmFAD7 and GmFAD8 of cultivar Dare. Dare GmFAD7 transcript expression in leaves remained at a relatively low level and was unaffected by any of the temperature treatments we imposed, but GmFAD8 transcript accumulation was sharply upregulated by a cool temperature (20/16°C day/night) after a 12 h exposure and total linolenic acid as a percent of total leaf fatty acids increased from 60 to about 68% after 48 h at the cool temperature. Inoculation of soybean leaves with the fungal pathogen Cercospora kikuchii differentially upregulated the level of GmFAD7 transcripts to twice that of GmFAD8 by 12 h postinoculation. The response of soybean foliar FAD8 expression and linolenic acid levels to cool temperature was similar to observations in other plants. On the other hand, despite increased soybean FAD7 expression in response to foliar pathogen stress the expected associated increase in foliar linolenic acid was not detected.
Maturity and Regrowth Influences on Quality of Caucasian Bluestem Hay
Authors: Burns J.C.
Published: June 2011

Caucasian bluestem [CBS; Bothriochloa caucasica (Trin.) C.E. Hubbard ‘Caucasian’] appears adapted to the mid‐Atlantic region. Three experiments, one with sheep and two with steers, were conducted to assess hay quality. In Experiment (Exp.) 1, initial growth was cut at early boot, anthesis, and postanthesis and regrowth cut at early boot and anthesis (five treatments) and evaluated by wether sheep. All treatments, except regrowth anthesis were also evaluated in a preliminary experiment with steers. In Exp. 2, regrowth was cut at the same three initial growth stages as in Exp. 1 and evaluated by steers. Sheep readily ate CBS hay, consuming 1.88 kg 100 kg−1 body weight (BW) when the hay was cut at early boot, with apparent dry matter digestion (DMD) of 647 g kg−1. Intake decreased linearly by postanthesis to 1.45 kg 100 kg−1 BW with DMD of 548 g kg−1. Steers also readily ate early‐boot CBS hay, averaging 2.49 kg 100 kg−1 BW with DMD of 661 g kg−1. Intake decreased linearly by postanthesis to 1.48 kg 100 kg−1 BW with a DMD of 589 g kg−1. Sheep and steer intake was well correlated (r = 0.951; P = 0.05) as was DMD (r = 0.939; P = 0.06). In Exp. 2, steers readily consumed regrowth hay, averaging 2.73 kg 100 kg−1 BW for the early‐boot cut with a DMD of 670 g kg−1. Intake declined linearly by postanthesis to 1.57 kg 100 kg−1 BW with a DMD of 517 g kg−1. Hays of CBS can provide desirable quality for animal production systems if it is cut by the early‐boot stage in the mid‐Atlantic region of the United States.
Instability of the Greens‐Type Phenotype in Poa annua L.
Authors: La Mantia Jonathan M. , Huff David R.
Published: June 2011

The turfgrass species Poa annua L. is most prevalent as an invasive, annual weed in managed turfs. Conversely, the dwarf perennial greens‐type biotype produces a high turf quality with great utility to the golf‐course industry. In the past 60 yr, several attempts have been made to breed a commercial cultivar of the greens‐type biotype with little sustained success. Here, we characterize the morphological traits of the greens‐type phenotype and investigate its inheritance and stability through genetic crosses. The results indicate that the greens‐type phenotype links single‐branching inflorescences with reductions in culm length, tiller length, leaf length, and panicle length to a single genetic mechanism. However, in advanced‐generation progeny, the segregation of the greens‐type phenotype does not conform to the disomic single‐gene inheritance model. Tetrasomic inheritance, gene complementation, and quantitative inheritance models are also presented. These results, along with the observation of somatic reversions, suggest that the greens‐type phenotype is unstable and may be regulated by an epigenetic mechanism.
Environment and Hybrid Influences on Rapid‐Visco‐Analysis Flour Properties of Food‐Grade Grain Sorghum
Authors: Griess Joni K. , Mason Stephen C. , Jackson David S. , Galusha Tomie D. , Pedersen Jeffrey F. , Yaseen Muhammad
Published: June 2011

Grain processors would benefit from information about the production environment and the influences of the sorghum [Sorghum bicolor (L.) Moench] hybrid on food‐grade flour properties. The objective of this study was to determine the effects of environment and hybrid on rapid‐visco‐analysis (RVA) flour properties of commercially available food‐grade sorghum. A randomized complete block experiment was planted in 12 environments, which included the 2004 and 2005 growing seasons and irrigated and dryland water regimes in eastern, central, and west central Nebraska, and a dryland, low‐N environment in eastern Nebraska. The environment accounted for 71–85% of the total variation in RVA parameters, while the hybrid accounted for 11–23% and the environment‐by‐hybrid interaction, 1–3%. Unfortunately, the results of this experiment suggest that it is difficult to predict the effect that environment will have on resulting sorghum‐flour parameters. Although of secondary importance in terms of total variation in sorghum‐flour RVA properties, the choice of hybrid predictably and significantly contributes to sorghum‐starch viscosity properties. Food‐grade hybrids were grouped based on viscosity properties into those best suited for dry‐mill and alkaline‐cooked products (Asgrow Orbit; Sorghum Partners NK1486) and those best suited for porridge, consumable alcohol, and ethanol production (Kelly Green Seeds KG6902; NC+ Hybrids 7W92; Asgrow Eclipse; and Fontanelle W‐1000). These results were consistent with those previously reported for grain density.
Ensuring Genetic Purity of Pigeonpea Hybrids by Incorporating a Naked‐Eye Polymorphic Marker in A and B Lines
Authors: Saxena K. B. , Vales M. I. , Kumar R. V. , Sultana R. , Srivastava R. K.
Published: June 2011

To enhance the productivity of pigeonpea [Cajanus cajan (L.) Millspaugh] a hybrid breeding technology, based on the cytoplasmic nuclear male‐sterility (CMS) system and partial natural outcrossing, is currently been used. However, there are difficulties to maintain genetic purity of the hybrids and their parents. The incorporation of an easily identifiable morphological marker (naked eye polymorphism [NEP]) could be used to determine seed purity. The morphological marker selected for this study, obcordate leaf, is not present in cultivated pigeonpea; it is inherited as a single recessive gene and can be observed soon after planting (approx. 6 wk). To incorporate the obcordate leaf shape into hybrid parents, the trait was transferred from the germplasm accession ICP 5529 into male‐sterile (A lines) and the corresponding maintainers (B lines). The hybrids derived from crosses involving obcordate leaf A lines and normal leaf fertility restorers (R lines) were fully fertile and had normal lanceolate leaves; thus the difference between A line and hybrids was clear. The use of obcordate leaf as a NEP marker in pigeonpea would contribute to preserve parental line purity and confirm hybrid status.
The effectiveness and sustainability of two demand-driven sanitation and hygiene approaches in Zimbabwe
Authors: Whaley L. , Webster J.
Published: June 2011

Since 2000 a number of community-driven sanitation approaches have emerged that counter a historical trend to subsidise the provision of latrines to the poor. This study reports on a set of findings and conclusions concerning the effectiveness and sustainability of two such approaches operating in Zimbabwe, the community health club (CHC) approach and community-led total sanitation (CLTS). Surveys, interviews and focus groups were conducted in a total of ten project communities from three districts. Results show that, despite little resistance to the idea, a household's ability to own a latrine depends heavily on its ability to afford one. Affordability is also key in moving up the ‘sanitation ladder’, which is necessary if behaviour change is to be sustained in the long term. Whilst both approaches effectively encouraged measures that combat open defecation, only health clubs witnessed a significant increase in the adoption of hand washing. However, CLTS proved more effective in promoting latrine construction, suggesting that the emphasis the CHCs place on hygiene practices such as hand washing needs to be coupled with an even stronger focus on the issue of sanitation brought by CLTS.
A solution of an open problem concerning Lagrangian mean-type mappings
Authors: Głazowska Dorota
Published: June 2011

The problem of invariance of the geometric mean in the class of Lagrangian means was considered in [Głazowska D., Matkowski J., An invariance of geometric mean with respect to Lagrangian means, J. Math. Anal. Appl., 2007, 331(2), 1187–1199], where some necessary conditions for the generators of Lagrangian means have been established. The question if all necessary conditions are also sufficient remained open. In this paper we solve this problem.
Modern approaches to modeling user requirements on resource and task allocation in hierarchical computational grids
Authors: Kołodziej Joanna , Xhafa Fatos
Published: June 2011

Modern approaches to modeling user requirements on resource and task allocation in hierarchical computational grids

Tasks scheduling and resource allocation are among crucial issues in any large scale distributed system, including Computational Grids (CGs). These issues are commonly investigated using traditional computational models and resolution methods that yield near-optimal scheduling strategies. One drawback of such approaches is that they cannot effectively tackle the complex nature of CGs. On the one hand, such systems account for many administrative domains with their own access policies, user privileges, etc. On the other, CGs have hierarchical nature and therefore any computational model should be able to effectively express the hierarchical architecture in the optimization model. Recently, researchers have been investigating the use of game theory for modeling user requirements regarding task and resource allocation in grid scheduling problems. In this paper we present two general non-cooperative game approaches, namely, the symmetric non-zero sum game and the asymmetric Stackelberg game for modeling grid user behavior defined as user requirements. In our game-theoretic approaches we are able to cast new requirements arising in allocation problems, such as asymmetric users relations, security and reliability restrictions in CGs. For solving the games, we designed and implemented GA-based hybrid schedulers for approximating the equilibrium points for both games. The proposed hybrid resolution methods are experimentally evaluated through the grid simulator under heterogeneity, and large-scale and dynamics conditions. The relative performance of the schedulers is measured in terms of the makespan and flowtime metrics. The experimental analysis showed high efficiency of meta-heuristics in solving the game-based models, especially in the case of an additional cost of secure task scheduling to be paid by the users.
Resource and service discovery in SOAs: A P2P oriented semantic approach
Authors: Di Modica Giuseppe , Tomarchio Orazio , Vita Lorenzo
Published: June 2011

Resource and service discovery in SOAs: A P2P oriented semantic approach

An intense standardization process is favouring the convergence of grids and Service Oriented Architectures (SOAs). One of the benefits of such technological convergence is that grid resources and applications can be virtualized by services and offered through the SOA paradigm. In the broad and interoperable scenarios enabled by the SOA, involving the participation of several grid infrastructures across many administrative domains, service discovery can be a serious issue. In this paper we present a P2P-based infrastructure that leverages semantic technologies to support a scalable and accurate service discovery process. The key concept of the presented idea is the creation of an overlay network organized in several semantic groups of peers, each specialized in answering queries pertaining to specific applicative domains. Groups are formed by clustering together peers offering services that are semantically related. The architecture details of the proposed solution are presented. A system prototype has also been implemented and validated through a case study deployed on the PlanetLab testbed.
P2P video streaming combining SVC and MDC
Authors: de Asís López-Fuentes Francisco
Published: June 2011

P2P video streaming combining SVC and MDC

In this paper we propose and evaluate a combined SVC-MDC (Scalable Video Coding & Multiple Description Video Coding) video coding scheme for Peer-to-Peer (P2P) video multicast. The proposed scheme is based on a full cooperation established between the peer sites, which contribute their upload capacity during video distribution. The source site splits the video content into many small blocks and assigns each block to a single peer for redistribution. Our solution is implemented in a fully meshed P2P network in which peers are connected to each other via UDP (User Datagram Protocol) links. The video content is encoded by using the Scalable Video Coding (SVC) method. We present a flow control mechanism that allows us to optimize dynamically the overall throughput and to automatically adjust video quality for each peer. Thus, peers with different upload capacity receive different video quality. We also combine the SVC method with Multiple Description Coding (MDC) to alleviate the packet loss problem. We implemented and tested this approach in the PlanetLab infrastructure. The obtained results show that our solution achieves good performance and remarkable video quality in the presence of packet loss.
Random perturbation of the projected variable metric method for nonsmooth nonconvex optimization problems with linear constraints
Authors: El Mouatasim Abdelkrim , Ellaia Rachid , de Cursi Eduardo
Published: June 2011

Random perturbation of the projected variable metric method for nonsmooth nonconvex optimization problems with linear constraints

We present a random perturbation of the projected variable metric method for solving linearly constrained nonsmooth (i.e., nondifferentiable) nonconvex optimization problems, and we establish the convergence to a global minimum for a locally Lipschitz continuous objective function which may be nondifferentiable on a countable set of points. Numerical results show the effectiveness of the proposed approach.
Akt-Mediated Proinflammatory Response of Mononuclear Phagocytes Infected with Burkholderia cenocepacia Occurs by a Novel GSK3β-Dependent, IκB Kinase-Independent Mechanism
Authors: Cremer Thomas J. , Shah Prexy , Cormet-Boyaka Estelle , Valvano Miguel A. , Butchar Jonathan P. , Tridandapani Susheela
Published: June 2011

The environmental bacterium Burkholderia cenocepacia causes opportunistic lung infections in immunocompromised individuals, particularly in patients with cystic fibrosis. Infections in these patients are associated with exacerbated inflammation leading to rapid decay of lung function, and in some cases resulting in cepacia syndrome, which is characterized by a fatal acute necrotizing pneumonia and sepsis. B. cenocepacia can survive intracellularly in macrophages by altering the maturation of the phagosome, but very little is known on macrophage responses to the intracellular infection. In this study, we have examined the role of the PI3K/Akt signaling pathway in B. cenocepacia-infected monocytes and macrophages. We show that PI3K/Akt activity was required for NF-κB activity and the secretion of proinflammatory cytokines during infection with B. cenocepacia. In contrast to previous observations in epithelial cells infected with other Gram-negative bacteria, Akt did not enhance IκB kinase or NF-κB p65 phosphorylation, but rather inhibited GSK3β, a negative regulator of NF-κB transcriptional activity. This novel mechanism of modulation of NF-κB activity may provide a unique therapeutic target for controlling excessive inflammation upon B. cenocepacia infection.
The Programmed Death-1 Ligand 1:B7-1 Pathway Restrains Diabetogenic Effector T Cells In Vivo
Authors: Paterson Alison M. , Brown Keturah E. , Keir Mary E. , Vanguri Vijay K. , Riella Leonardo V. , Chandraker Anil , Sayegh Mohamed H. , Blazar Bruce R. , Freeman Gordon J. , Sharpe Arlene H.
Published: June 2011

Programmed death-1 ligand 1 (PD-L1) is a coinhibitory molecule that negatively regulates multiple tolerance checkpoints. In the NOD mouse model, PD-L1 regulates the development of diabetes. PD-L1 has two binding partners, programmed death-1 and B7-1, but the significance of the PD-L1:B7-1 interaction in regulating self-reactive T cell responses is not yet clear. To investigate this issue in NOD mice, we have compared the effects of two anti–PD-L1 Abs that have different blocking activities. Anti–PD-L1 mAb 10F.2H11 sterically and functionally blocks only PD-L1:B7-1 interactions, whereas anti–PD-L1 mAb 10F.9G2 blocks both PD-L1:B7-1 and PD-L1:programmed death-1 interactions. Both Abs had potent, yet distinct effects in accelerating diabetes in NOD mice: the single-blocker 10F.2H11 mAb was more effective at precipitating diabetes in older (13-wk-old) than in younger (6- to 7-wk-old) mice, whereas the dual-blocker 10F.9G2 mAb rapidly induced diabetes in NOD mice of both ages. Similarly, 10F.2H11 accelerated diabetes in recipients of T cells from diabetic, but not prediabetic mice, whereas 10F.9G2 was effective in both settings. Both anti–PD-L1 mAbs precipitated diabetes in adoptive transfer models of CD4+ and CD8+ T cell-driven diabetes. Taken together, these data demonstrate that the PD-L1:B7-1 pathway inhibits potentially pathogenic self-reactive effector CD4+ and CD8+ T cell responses in vivo, and suggest that the immunoinhibitory functions of this pathway may be particularly important during the later phases of diabetogenesis.
Recognition of Dual or Multiple Pathology in Skin Biopsies from Patients with HIV/AIDS
Authors: Grayson Wayne
Published: June 2011

A large percentage of patients with HIV/AIDS will develop dermatological complications. Consequently, all practising clinicians and pathologists in regions with a high prevalence of HIV/AIDS must be familiar with the diverse cutaneous manifestations of the disease. This paper highlights the fact that biopsy material in this clinical context may occasionally reveal more than one pathological process. The potential spectrum includes two or more infections in a single skin biopsy (e.g., herpes simplex and cytomegalovirus infection), neoplastic lesions containing infective organisms (Kaposi sarcoma (KS) and cryptococcosis), dermatoses in association with neoplastic lesions (e.g., KS and interface dermatitis), or more than one dermatosis in a given specimen (e.g., papulopruritic eruption and nodular prurigo). Rare biopsies may even demonstrate triple pathology. The importance of careful examination of skin biopsies in this clinical context is emphasised. Failure to recognise an undiagnosed concomitant opportunistic infective pathogen could have potentially disastrous consequences for the patient.
Management of employee wellness in South Africa: Employer, service provider and union perspectives
Authors: Sieberhagen Charlotte , Pienaar Jaco , Els Crizelle
Published: June 2011

Orientation: This article focuses on how South African organisations manage their employees’ wellness through their Employee Wellness Programmes (EWPs). Research purpose: The objective of this research is to describe employee wellness in South Africa by investigating the types, foci and perceived success of EWPs.Motivation for the study: Despite the growing awareness of the importance of EWPs in South Africa, the nature, content, context, participants, role-players and anticipated benefits as well as the possible drawbacks of these programmes in the South African context are unclear.Research design, approach and method: The researchers used a cross-sectional design. The first author developed the Employee Wellness Survey, consisting of quantitative and qualitative questions, to collect data from 16 organisations, four service providers and seven labour unions in South Africa.Main findings: The results showed that organisations, service providers and labour unions define employee wellness differently and that these role players give different reasons for introducing EWPs. Almost half of the participating organisations have no baseline measurement with which to compare the effectiveness of their EWPs. Generally, all the organisations present the results of their programmes reasonably. However, the programmes involve little overall expenditure to the organisations.Practical/managerial implications: Organisations should monitor the state of their employees’ wellness in order to manage it effectively. This will only become possible when information about employee wellness improves.Contribution/value-add: This study provides new information about the nature, content, context, participants, role-players, anticipated benefits and possible drawbacks of EWPs in the South-African context.
Case report: MRI of decubital ischemic fasciitis
Authors: Ulus Ozden Sila , Karaarslan Ercan , Saglican Yesim , Yakupoglu Abdullah
Published: June 2011

The MRI findings in a case of decubital ischemic fasciitis located posterolateral to the right greater trochanter, in a 72-year-old woman, are presented. Decubital ischemic fasciitis is an uncommon entity encountered mostly in debilitated, elderly patients, in the deep subcutaneous tissue, at pressure points or bony prominences. It can simulate soft-tissue sarcomas. Recognition of this lesion radiologically is important to prevent unnecessary interventions.
Technical note: Radiofrequency ablation of hepatocellular carcinoma with contrast-enhanced ultrasound guidance: First Indian experience
Authors: Kapoor Atul , Kapoor Aprajita , Mahajan Goldaa
Published: June 2011

Radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) is an established alternative treatment to surgery and intra-arterial chemotherapy, usually performed under contrast-enhanced CT scan guidance. We describe our experience with the use of contrast-enhanced ultrasound and contrast dynamics analysis for planning and monitoring RFA in a patient with HCC.
Utility of magnetic resonance imaging in the evaluation of patients with ST segment elevation on an electrocardiogram
Authors: Rajiah Prabhakar
Published: June 2011

ST segment elevation is an important electrocardiographic (ECG) change that is typically found in acute myocardial infarction, but may also be seen in a variety of other conditions. MRI plays an important role in the evaluation of these patients. MRI not only establishes the diagnosis, which is essential for appropriate management, but also helps in the assessment of other factors that are important for risk stratification. In this review, we discuss the common and uncommon causes of ST segment elevation and the role of MRI in the evaluation of these disease processes.
Imaging of serous psammomacarcinoma of ovary with subcutaneous deposits: A case report
Authors: Diwakar Nagaraj , Kamble Ravindra B , Dixit Jagannath , Gangadhara Dashavara Sreekantaiah , Shetty Roshan V
Published: June 2011

Serous psammomacarcinoma of ovary is a rare ovarian carcinoma. We present the imaging features of this condition in a patient with a probable metastatic subcutaneous nodule.
Topiramate: Safety and Efficacy of its Use in the Prevention and Treatment of Migraine
Authors: Minton Ginger C. , Miller April D. , Bookstaver P. Brandon , Love Bryan L.
Published: June 2011

Migraine headaches are typically episodic in nature and may affect nearly 10% of the population. In addition to treatment, prevention of subsequent episodes or progression to a chronic migraine state is an important therapeutic area. Topiramate is a centrally acting medication approved for both the prevention of seizures and migraine headache. At this time, the exact mechanism of how topiramate assists in migraine prevention is unknown. Several large randomized, controlled trials have aided in establishing topiramate's role in migraine prevention. Despite a favorable pharmacokinetic and adverse effect profile established in clinical trials, several additional studies, case reports and toxicology reports have demonstrated topiramate as a cause of cognitive and behavioural changes. The use of topiramate in migraine prevention can improve a patient's quality of life and is a cost-effective option for migraine prevention.
Effect of Four Different Placement Techniques on Marginal Microleakage in Class II Composite Restorations: An in vitro Study
Authors: Bugalia Anupriya , Usha G , Karthik J , Rao Raghoothama , Vedhavathi B
Published: June 2011

Background and objectives

This study was undertaken to evaluate the effect of different placement techniques (bulk, oblique incremental, centripetal and split horizontal) on marginal microleakage in class II composite restoration.

Method

Standardized class II preparations were made in 40 caries-free extracted molars and randomly assigned to four groups (n = 10): (1) Bulk technique (2) oblique incremental insertion technique,(3) centripetal incremental insertion technique and (4) split horizontal incremental insertion. The teeth were restored with a total-etch adhesive and nanocomposite resin. The specimens were immersed in a solution of 2% methylene blue for 24 hours, and subsequently evaluated for leakage. The microleakage scores (0 to 4) obtained from the occlusal and cervical walls were analyzed with Kruskal-Wallis and Mann-Whitney tests (p < 0.05).

Results

Microleakage scores indicated that incremental technique was better than bulk for composite placement and among incremental techniques split incremental technique showed best results.

Conclusion

Incremental placement technique showed lower microleakage compared to bulk, and lower microleakage was seen at occlusal margin compared to gingival margin. Split horizontal incremental technique showed the least microleakage scores among incremental techniques
Morphological Evaluation of the Bovine Dentin prepared with High-speed Turbine or Er:YAG Laser and submitted to Different Adhesive Systems after Laser Etching
Authors: Torres Carlos Rocha Gomes , Huhtala Maria Filomena Rocha Lima , Teixeira Simone Cristina , Araujo Maria Amélia Máximo de
Published: June 2011

This study evaluated the effect of the Er:YAG laser at different settings on the surface of bovine dentin as well as adhesive systems. A total of 21 bovine teeth had their apexes embedded in chemically activated acrylic resin to allow sectioning of a dentin slice parallel to the buccal aspect of each tooth. Thus, group A (12 slices), prepared with the high-speed turbine, being four for analysis of the dentin surface, four for analysis of the interface and four for analysis of resin tags. Group B (9 slices) prepared with the Er:YAG laser, being three for analysis of the surface, three for analysis of the interface and three for analysis of resin tags. Each slice received a different treatment: etching with phosphoric acid, Er:YAG laser (60 mJ/10 Hz), conventional adhesive Excite (Vivadent) and self-etching adhesive One-Up Bond F (Tokuyama). For analysis of the interface, all slices were fractured for exposure of the resin/dentin bond. All slices were processed to allow evaluation by scanning electron microscopy. The results revealed that the Er:YAG laser employed both for preparation and dentin etching removed the smear layer, opened the dentinal tubules and yielded surface cracks; there was formation of a large amount and deep tags in the study groups, except for the slice prepared with diamond bur at high-speed and self-etching adhesive systems; the interfaces revealed adequate adaptation of the adhesive system/composite resin to the dentin, with little evidence of hybrid layer; also, the slice prepared with diamond bur, etched with phosphoric acid and receiving the Excite adhesive system displayed a porous hybrid layer.
Reattachment of an Autogenous Tooth Fragment in Complicated Crown Fracture
Authors: Kore Preeti , Kumar Shikhar
Published: June 2011

The occurrence of dental traumas in children is on the rise, according to the literature, and require correct and adequate treatment specific to each fracture in order to preserve the remaining tooth. This article reports a case of a complicated crown fracture of maxillary right central incisor. It describes the reattachment of the original tooth fragment to the fractured tooth, provides benefits of maintaining the tooth's shape, color texture and translucency of the restoration.
Investigating the use of secondary organic aerosol as seed particles in simulation chamber experiments
Authors: Hamilton J. F. , Rami Alfarra M. , Wyche K. P. , Ward M. W. , Lewis A. C. , McFiggans G. B. , Good N. , Monks P. S. , Carr T. , White I. R. , Purvis R. M.
Published: June 2011

Abstract. The use of β-caryophyllene secondary organic aerosol particles as seeds for smog chamber simulations has been investigated. A series of experiments were carried out in the Manchester photochemical chamber as part of the Aerosol Coupling in the Earth System (ACES) project to study the effect of seed particles on the formation of secondary organic aerosol (SOA) from limonene photo-oxidation. Rather than use a conventional seed aerosol containing ammonium sulfate or diesel particles, a method was developed to use in-situ chamber generated seed particles from β-caryophyllene photo-oxidation, which were then diluted to a desired mass loading (in this case 4–13 μg m−3). Limonene was then introduced into the chamber and oxidised, with the formation of SOA seen as a growth in the size of oxidised organic seed particles from 150 to 325 nm mean diameter. The effect of the partitioning of limonene oxidation products onto the seed aerosol was assessed using aerosol mass spectrometry during the experiment and the percentage of m/z 44, an indicator of degree of oxidation, increased from around 5 to 8 %. The hygroscopicity of the aerosol also changed, with the growth factor for 200 nm particles increasing from less than 1.05 to 1.25 at 90 % RH. The detailed chemical composition of the limonene SOA could be extracted from the complex β-caryophyllene matrix using two-dimensional gas chromatography (GC × GC) and liquid chromatography coupled to mass spectrometry. High resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS) was used to determine exact molecular formulae of the seed and the limonene modified aerosol. The average O:C ratio was seen to increase from 0.32 to 0.37 after limonene oxidation products had condensed onto the organic seed.
Aerosol climatology and planetary boundary influence at the Jungfraujoch analyzed by synoptic weather types
Authors: Collaud Coen M. , Weingartner E. , Furger M. , Nyeki S. , Prévôt A. S. H. , Steinbacher M. , Baltensperger U.
Published: June 2011

Abstract. Fourteen years of meteorological parameters, aerosol variables (absorption and scattering coefficients, aerosol number concentration) and trace gases (CO, NOx, SO2) measured at the Jungfraujoch (JFJ, 3580 m a.s.l.) have been analyzed as a function of different synoptic weather types. The Schüepp synoptic weather type of the Alps (SYNALP) classification from the Alpine Weather Statistics (AWS) was used to define the synoptic meteorology over the whole Swiss region. The seasonal contribution of each synoptic weather type to the aerosol concentration was deduced from the aerosol annual cycles while the planetary boundary layer (PBL) influence was estimated by means of the diurnal cycles. Since aerosols are scavenged by precipitation, the diurnal cycle of the CO concentration was also used to identify polluted air masses. SO2 and NOx concentrations were used as precursor tracers for new particle formation and growth, respectively. The aerosol optical parameters and number concentration show elevated loadings during advective weather types during the December–March period and for the convective anticyclonic and convective indifferent weather types during the April–September period. This study confirms the consensus view that the JFJ is mainly influenced by the free troposphere during winter and by injection of air parcels from the PBL during summer. A more detailed picture is, however, drawn where the JFJ is completely influenced by free tropospheric air masses in winter during advective weather types and largely influenced by the PBL also during the night in summer during the subsidence weather type. Between these two extreme situations, the PBL influence at the JFJ depends on both the time of year and the synoptic weather type. The fraction of PBL air transported to the JFJ was estimated by the relative increase of the specific humidity and CO.
Investigations of primary and secondary particulate matter of different wood combustion appliances with a high-resolution time-of-flight aerosol mass spectrometer
Authors: Heringa M. F. , DeCarlo P. F. , Chirico R. , Tritscher T. , Dommen J. , Weingartner E. , Richter R. , Wehrle G. , Prévôt A. S. H. , Baltensperger U.
Published: June 2011

Abstract. A series of photo-oxidation smog chamber experiments were performed to investigate the primary emissions and secondary aerosol formation from two different log wood burners and a residential pellet burner under different burning conditions: starting and flaming phase. Emissions were sampled from the chimney and injected into the smog chamber leading to primary organic aerosol (POA) concentrations comparable to ambient levels. The composition of the aerosol was measured by an Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) and black carbon (BC) instrumentation. The primary emissions were then exposed to xenon light to initiate photo-chemistry and subsequent secondary organic aerosol (SOA) production. After correcting for wall losses, the average increase in organic matter (OM) concentrations by SOA formation for the starting and flaming phase experiments with the two log wood burners was found to be a factor of 4.1±1.4 after five hours of aging. No SOA formation was observed for the stable burning phase of the pellet burner. The startup emissions of the pellet burner showed an increase in OM concentration by a factor of 3.3. Including the measured SOA formation potential, average emission factors of BC+POA+SOA, calculated from CO2 emission, were found to be in the range of 0.04 to 3.9 g/kg wood for the stable burning pellet burner and an old log wood burner during startup respectively. SOA contributed significantly to the ion C2H4O2+ at mass to charge ratio m/z 60, a commonly used marker for primary emissions of wood burning. This contribution at m/z 60 can overcompensate for the degradation of levoglucosan leading to an overestimation of the contribution of wood burning or biomass burning to the total OM. The primary organic emissions from the three different burners showed a wide range in O:C atomic ratio (0.19−0.60) for the starting and flaming conditions, which also increased during aging. Primary wood burning emissions have a rather low relative contribution at m/z 43 (f 43) to the total organic mass spectrum. The non-oxidized fragment C3H7+ has a considerable contribution at m/z 43 for the fresh OA with an increasing contribution of the oxygenated ion C2H3O+ during aging. After five hours of aging, the OA has a rather low C2H3O+ signal for a given CO2+ fraction, possibly indicating a higher ratio of acid to non-acid oxygenated compounds in wood burning OA compared to other oxygenated organic aerosol (OOA).
Predicting the relative humidities of liquid-liquid phase separation, efflorescence, and deliquescence of mixed particles of ammonium sulfate, organic material, and water using the organic-to-sulfate mass ratio of the particle and the oxygen-to-carbon elemental ratio of the organic component
Authors: Bertram A. K. , Martin S. T. , Hanna S. J. , Smith M. L. , Bodsworth A. , Chen Q. , Kuwata M. , Liu A. , You Y. , Zorn S. R.
Published: June 2011

Abstract. Individual particles that on a mass basis consist dominantly of the components ammonium sulfate, organic material, and water are a common class of submicron particles found in today's atmosphere. Here we use (1) the organic-to-sulfate (org:sulf) mass ratio of the overall particle and (2) the oxygen-to-carbon (O:C) elemental ratio of the organic component as input variables in parameterisations that predict the critical relative humidity of several different types of particle phase transitions. These transitions include liquid-liquid phase separation (SRH), efflorescence (ERH), and deliquescence (DRH). Experiments were conducted by optical microscopy for 11 different oxygenated organic-ammonium sulfate systems covering the range 0.1 < org:sulf <12.8 and 0.29 < O:C < 1.33. These new data, in conjunction with other data already available in the literature, were used to develop the parameterisations SRH(org:sulf, O:C), ERH(org:sulf, O:C), and DRH(org:sulf, O:C). The parameterisations correctly predicted SRH within 15 % RH for 86 % of the measurements, ERH within 5 % for 86 % of the measurements, and DRH within 5 % for 95 % of the measurements. The applicability of the derived parameterisations beyond the training data set was tested against observations for organic-sulfate particles produced in an environmental chamber. The organic component consisted of secondary organic material produced by the oxidation of isoprene, α-pinene, and β-caryophyllene. The predictions of the parameterisations were also tested against data from the Southern Great Plains, Oklahoma, USA. The observed ERH and DRH values for both the chamber and field data agreed within 5 % RH with the value predicted by the parameterisations using the measured org:sulf and O:C ratios as the input variables.
Accounting for non-linear chemistry of ship plumes in the GEOS-Chem global chemistry transport model
Authors: Vinken G. C. M. , Boersma K. F. , Jacob D. J. , Meijer E. W.
Published: June 2011

Abstract. We present a computationally efficient approach to account for the non-linear chemistry occurring during the dispersion of ship exhaust plumes in a global 3-D model of atmospheric chemistry (GEOS-Chem). We use a plume-in-grid formulation where ship emissions age chemically for 5 h before being released in the global model grid. Besides reducing the original ship NOx emissions in GEOS-Chem, our approach also releases the secondary compounds ozone and HNO3, produced in the 5 h after the original emissions, into the model. We applied our improved method and also the widely used "instant dilution" approach to a 1-yr GEOS-Chem simulation of global tropospheric ozone-NOx-VOC-aerosol chemistry. We also ran simulations with the standard model, and a model without any ship emissions at all. Our improved GEOS-Chem model simulates up to 0.1 ppbv (or 90 %) more NOx over the North Atlantic in July than GEOS-Chem versions without any ship NOx emissions at all. "Instant dilution" overestimates NOx concentrations by 50 % (0.1 ppbv) and ozone by 10–25 % (3–5 ppbv) over this region. These conclusions are supported by comparing simulated and observed NOx and ozone concentrations in the lower troposphere over the Pacific Ocean. The comparisons show that the improved GEOS-Chem model simulates NOx concentrations in between the instant diluting model and the model with no ship emissions, and results in lower O3 concentrations than the instant diluting model. The relative differences in simulated NOx and ozone between our improved approach and instant dilution are smallest over strongly polluted seas (e.g. North Sea), suggesting that accounting for in-plume chemistry is most relevant for pristine marine areas.
Variable lifetimes and loss mechanisms for NO3 and N2O5 during the DOMINO campaign: contrasts between marine, urban and continental air
Authors: Crowley J. N. , Thieser J. , Tang M. , Schuster G. , Bozem H. , Hosaynali Beygi Z. , Fischer H. , Diesch J. , Drewnick F. , Borrmann S. , Song W. , Yassaa N. , Williams J. , Pöhler D. , Platt U. , Lelieveld J.
Published: June 2011

Abstract. Nighttime mixing ratios of boundary layer N2O5 were determined using cavity-ring-down spectroscopy during the DOMINO campaign. Observation of N2O5 was intermittent, with mixing ratios ranging from below the detection limit (~5 ppt) to ~500 ppt. A steady-state analysis constrained by measured mixing ratios of NO2 and O3 was used to derive NO3 lifetimes and compare them to calculated rates of loss via gas-phase and heterogeneous reactions of both NO3 and N2O5. Three distinct types of air masses were encountered, which were largely marine (Atlantic), continental or urban-industrial in origin. NO3 lifetimes were longest in the Atlantic sector (up to ~30 min) but were very short (a few seconds) in polluted, air masses from the local city and petroleum-related industrial complex of Huelva. Air from the continental sector was an intermediate case. The high reactivity to NO3 of the urban air mass was not accounted for by gas-phase and heterogeneous reactions, rates of which were constrained by measurements of NO, volatile organic species and aerosol surface area. In general, high NO2 mixing ratios resulted in low NO3 lifetimes, though heterogeneous processes (e.g. reaction of N2O5 on aerosol) were generally less important than direct gas-phase losses of NO3. The presence of SO2 at levels above ~2 ppb in the urban air sector was always associated with very low N2O5 mixing ratios indicating either very short NO3 lifetimes in the presence of combustion-related emissions or an important role for reduced sulphur species in urban, nighttime chemistry. High production rates coupled with low lifetimes of NO3 imply an important contribution of nighttime chemistry to removal of both NOx and VOC.
Constraining global methane emissions and uptake by ecosystems
Authors: Spahni R. , Wania R. , Neef L. , van Weele M. , Pison I. , Bousquet P. , Frankenberg C. , Foster P. N. , Joos F. , Prentice I. C. , van Velthoven P.
Published: June 2011

Abstract. Natural methane (CH4) emissions from wet ecosystems are an important part of today's global CH4 budget. Climate affects the exchange of CH4 between ecosystems and the atmosphere by influencing CH4 production, oxidation, and transport in the soil. The net CH4 exchange depends on ecosystem hydrology, soil and vegetation characteristics. Here, the LPJ-WHyMe global dynamical vegetation model is used to simulate global net CH4 emissions for different ecosystems: northern peatlands (45°–90° N), naturally inundated wetlands (60° S–45° N), rice agriculture and wet mineral soils. Mineral soils are a potential CH4 sink, but can also be a source with the direction of the net exchange depending on soil moisture content. The geographical and seasonal distributions are evaluated against multi-dimensional atmospheric inversions for 2003–2005, using two independent four-dimensional variational assimilation systems. The atmospheric inversions are constrained by the atmospheric CH4 observations of the SCIAMACHY satellite instrument and global surface networks. Compared to LPJ-WHyMe the inversions result in a~significant reduction in the emissions from northern peatlands and suggest that LPJ-WHyMe maximum annual emissions peak about one month late. The inversions do not put strong constraints on the division of sources between inundated wetlands and wet mineral soils in the tropics. Based on the inversion results we diagnose model parameters in LPJ-WHyMe and simulate the surface exchange of CH4 over the period 1990–2008. Over the whole period we infer an increase of global ecosystem CH4 emissions of +1.11 Tg CH4 yr−1, not considering potential additional changes in wetland extent. The increase in simulated CH4 emissions is attributed to enhanced soil respiration resulting from the observed rise in land temperature and in atmospheric carbon dioxide that were used as input. The long-term decline of the atmospheric CH4 growth rate from 1990 to 2006 cannot be fully explained with the simulated ecosystem emissions. However, these emissions show an increasing trend of +3.62 Tg CH4 yr−1 over 2005–2008 which can partly explain the renewed increase in atmospheric CH4 concentration during recent years.