Topology of pocket formation in turbulent premixed flames

© 2018 The Combustion Institute. In turbulent premixed flame propagation, the formation of isolated pockets of reactants or products is associated with flame pinch-off events which cause rapid changes in the flame surface area. Previous topological analysis of these phenomena has been carried out based on Morse theory and Direct Numerical Simulation (DNS) in two spatial dimensions. The present work extends the topological analysis to three dimensions with emphasis on the formation and subsequent burnout of reactant pockets. Singular behaviour observed previously for terms of the Surface Density Function (SDF) transport equation in the two-dimensional case is shown to occur also in three dimensions. Further singular behaviour is observed in the displacement speed close to reactant pocket burnout. The theory is compared against DNS data from hydrogen-air flames and good agreement is obtained

Toxic epidermal necrolysis following treatment of pseudotumour cerebri: a case report

Toxic Epidermal Necrolysis and Steven-Johnson syndrome are entities on a spectrum of cutaneous reactions that usually occur as an idiosyncratic reaction to certain drugs. The distinction between TEN and SJS is based on the percentage of skin involved with SJS being less than 10% and TEN being more than 30%. They exhibit severe skin blistering and sloughing with mucosal involvement and can be fatal in many cases. Discontinuation of the offending agent is mandatory together with reduction of skin manipulation and avoiding infection. Plasmapharesis, intravenous immunoglobulins and immunosuppressants have been used with conflicting results. In this manuscript we are describing a 22 year old female patient from Egypt who presented with severe skin sloughing with mucosal involvement following carbamazepine therapy. The incriminated drug was discontinued and urgent life saving therapy in the form of broad spectrum antibiotic, immunosuppression with cyclophosphamide, Intensive Care Unit admission and nursing care was started followed by dramatic response. The clinical presentation, pathogenesis and modalities of treatment will be described in details

Attention Deficit Hyperactivity Disorder, other mental health problems, substance use and driving: Examination of a population-based, representative Canadian sample

Purpose: The purpose of this study is to examine the relationships among self-reported screening measures of ADHD, other psychiatric problems, and driving-related outcomes in a provincially representative sample of adults 18 years and older living in the province of Ontario, Canada. Methods: The study examined the results of the Centre for Addictions and Mental Health (CAMH) Ontario Monitor, an ongoing repeated cross-sectional telephone survey of Ontario adults over a two year period. Measures: ADHD measures (Adult ADHD Self-Report Scale-V1.1 (ASRS-V1.1), previous ADHD diagnosis, ADHD medication use); psychiatric distress measures (General Health Questionnaire (GHQ12), pain, anxiety and depression medication use); antisocial behaviour measure (The Antisocial Personality Disorder Scale from the Mini-International Neuropsychiatric Interview (APD)); substance use and abuse measures (alcohol, cannabis and cocaine), Alcohol Use Disorders Identification Test (AUDIT), Alcohol, Smoking and Substance Involvement Screening Test (ASSIST)); driving-related outcomes (driving after drinking, driving after cannabis use, street racing, collisions in past year) and socio-demographics (gender, age, vehicle km travelled). Results: A total of 4014 Ontario residents were sampled, of which 3485 reported having a valid driver’s licence. Overall, 3.22% screened positively for ADHD symptoms on the ASRS-V1.1 screening tool. A greater percent of those who screened positively were younger, reported previous ADHD diagnosis and medication use, distress, antisocial behaviour, anti-anxiety and anti-depressant medication use, substance use and social problems compared to those who screened negatively. However, there were no statistically significant differences between those who screened positively or negatively for ADHD symptoms on self-reported driving after having two or more drinks in the previous hour, within an hour of using cannabis, marijuana or hash, in a street race or collision involvement as a driver in the past year. When a sequential regression was conducted to predict self-reported collisions, younger age, higher weekly kilometres driven showed higher odds of collision involvement, while the odds ratio for cannabis use ever, approached statistical significance. Discussion: This study is the first population-based study of a representative sample of adults 18 years and older living in Ontario, Canada. These results showed no relationship between the ADHD screen and collision when age, sex and kilometers driven are controlled for. However, these analyses are based on self-report screeners and not psychiatric diagnoses and a limited sample of ADHD respondents. Thus, these results should be interpreted with caution

Comparison of push-out bond strength of bioceramic sealer with bioceramic coated and non-bioceramic coated Guttapercha: an in vitro study

Background: The goal of the endodontic treatment is to achieve a fluid-tight impervious seal to prevent the ingress of bacteria and the occurrence of any pathology in future. The endodontic sealer plays a crucial role in obtaining the hermetic seal by filling all the spaces and by binding to the root dentin and to the core obturating material, which is usually gutta-percha. Aim: This study aimed to compare the push-out bond strength of Endosequence BC sealer with bioceramic coated gutta-percha and non-bioceramic coated gutta-percha. Materials and methods: A total of 36 extracted human maxillary central incisors were decoronated to standardize the root length of 15mm. Working length was determined and Biomechanical preparation for all the samples was done with a Mtwo (VDW Company) rotary file till 40/.06. Samples were randomly divided into three groups containing 12 teeth in each group based on the obturation procedure, namely Group 1: Endosequence BC sealer along with Endosequence bioceramic coated gutta-percha (n=12), Group 2: Endosequence BC sealer along with normal gutta-percha (n=12), Group 3: AH Plus sealer along with normal gutta-percha. All the samples were obturated using single cone technique. The specimens were sectioned orthogonally at middle third to obtain three sections of 1mm thick. All the samples were subjected to the push-out bond strength test with the universal testing machine. The data were subjected to one-way Analysis of Variance (ANOVA) followed by post hoc analysis. Results: Samples obturated with Endosequence BC sealer with Endosequence bioceramic coated gutta-percha showed the maximum push-out bond strength followed by Group 3 and Group 2.  One-way Anova showed significant differences (p=0.021) among the groups. In posthoc analysis, the specimens from group 1 exhibited significant differences (p=0.016) with the group 2 specimens. Conclusion: The push-out bond strength of Endosequence Bioceramic sealer with Endosequence Bioceramic coated gutta-percha was significantly higher than that of Endosequence Bioceramic sealer with normal gutta-percha and AH Plus sealer with normal gutta-percha

Apical microleakage assessment of teeth obturated with single-cone gutta-percha using two calcium silicate sealers and a resin sealer: an in vitro study.

Background: Achieving a fluid-tight seal of the root canal space is the most desirable outcome for the success of endodontic treatment. Root canal sealers are used in combination with core filling materials to fill the irregularities in the root canal, thereby obtaining a three-dimensional seal, which results in the inhibition of bacterial regrowth. Aim: This study was aimed to compare the apical sealing ability of three root canal sealers AH Plus, Endosequence BC, and Endoseal MTA, using a single cone gutta-percha obturation technique. Methodology: Forty extracted human single-rooted mandibular premolar teeth were decoronated to a standardized length of 15 mm and instrumented using crown down technique with the ProTaper gold rotary file system to apical file size F3. The roots were randomly allocated into three experimental groups (n=10) and two control groups (n=5). All the samples in experimental groups were obturated with a matched taper single cone: Group 1, Group 2 and Group 3 were obturated using AH Plus, Endosequence BC and Endoseal MTA sealers respectively. Samples were immersed in 1% Methylene blue dye solution for 72 hours, and then the roots were split longitudinally and observed under a stereomicroscope. Apical microleakage was measured from the apex to the most coronal level of dye penetration. The data obtained were subjected to statistical analysis. Results: Samples in all the groups showed evidence of leakage, except in the negative control group. Group I did not show significant differences with  Group 2 and Group 3 (p = 0.446 and p= 0.147, respectively). Whereas, statistically significant differences were observed between Group 2 and Group 3. Conclusion:  Endosequence BC showed a superior seal and less microleakage compared to the two other sealers used in this study using a single cone gutta-percha obturation technique

Anteroposterior chest radiograph vs. chest CT scan in early detection of pneumothorax in trauma patients

Pneumothorax is a common complication following blunt chest wall trauma. In these patients, because of the restrictions regarding immobilization of the cervical spine, Anteroposterior (AP) chest radiograph is usually the most feasible initial study which is not as sensitive as the erect chest X-ray or CT chest for detection of a pneumothorax. We will present 3 case reports which serve for better understanding of the entity of occult pneumothorax. The first case is an example of a true occult pneumothorax where an initial AP chest X-ray revealed no evidence of pneumothorax and a CT chest immediately performed revealed evidence of pneumothorax. The second case represents an example of a missed rather than a truly occult pneumothorax where the initial chest radiograph revealed clues suggesting the presence of pneumothorax which were missed by the reading radiologist. The third case emphasizes the fact that "occult pneumothorax is predictable". The presence of subcutaneous emphesema and pulmonary contusion should call for further imaging with CT chest to rule out pneumothorax. Thoracic CT scan is therefore the "gold standard" for early detection of a pneumothorax in trauma patients. This report aims to sensitize readers to the entity of occult pneumothorax and create awareness among intensivists and ER physicians regarding the proper diagnosis and management

The Impact of Childhood Symptoms of Conduct Disorder on Driver Aggression in Adulthood

Background: Despite limited empirical investigation, existing scientific literature suggests that individuals with a history or current diagnosis of conduct disorder (CD) may be more likely to demonstrate reckless and aggressive driving. Much of the limited research in this field examines the impact of childhood CD on driver behaviour and collision risk in young adults. Few, if any, studies assess the impact of this disorder on driver behaviour beyond age 21 years. The current research is a population-based study of the impact of CD symptoms during childhood on the risk of engaging in driver aggression during adulthood. Methods: Data are based on telephone interviews with 5,230 respondents who reported having driven in the past year. Data are derived from the 2011-2013 cycles of the CAMH Monitor, an ongoing cross-sectional survey of adults inOntario,Canada aged 18 years and older. A binary logistic regression analysis of self-reported driver aggression in the previous 12 months was conducted, consisting of measures of demographic characteristics, driving exposure, problem substance use, alcohol- and drug-impaired driving, symptoms of attention deficit hyperactivity disorder, and childhood (before age 15) symptoms of CD. Results: When entered with demographic characteristics, driving exposure, and other potential confounders, childhood symptoms of CD increased the odds of reporting driver aggression more than two-fold (adjusted OR=2.12). Exploratory analyses of the interaction between childhood symptoms of CD and age was not a significant predictor of driver aggression. Conclusions: Results suggest that symptoms of CD during childhood are associated with significantly increased odds of self-reported driver aggression during adulthood. Limitations and future directions of the research are discussed

Anatomy and origin of authochthonous late Pleistocene forced regression deposits, east Coromandel inner shelf, New Zealand: implications for the development and definition of the regressive systems tract

High-resolution seismic reflection data from the east Coromandel coast, New Zealand, provide details of the sequence stratigraphy beneath an autochthonous, wave dominated inner shelf margin during the late Quaternary (0-140 ka). Since c. 1 Ma, the shelf has experienced limited subsidence and fluvial sediment input, producing a depositional regime characterised by extensive reworking of coastal and shelf sediments during glacio-eustatic sea-level fluctuations. It appears that only one complete fifth-order (c. 100 000 yr) depositional sequence is preserved beneath the inner shelf, the late Pleistocene Waihi Sequence, suggesting any earlier Quaternary sequences were mainly cannibalised into successively younger sequences. The predominantly Holocene-age Whangamata Sequence is also evident in seismic data and modern coastal deposits, and represents an incomplete depositional sequence in its early stages of formation. A prominent aspect of the sequence stratigraphy off parts of the east Coromandel coast is the presence of forced regressive deposits (FRDs) within the regressive systems tract (RST) of the late Pleistocene Waihi Sequence. The FRDs are interpreted to represent regressive barrier-shoreface sands that were sourced from erosion and onshore reworking of underlying Pleistocene sediments during the period of slow falling sea level from isotope stages 5 to 2 (c. 112-18 ka). The RST is volumetrically the most significant depositional component of the Waihi Sequence; the regressive deposits form a 15-20 m thick, sharp-based, tabular seismic unit that downsteps and progrades continuously across the inner shelf. The sequence boundary for the Waihi Sequence is placed at the most prominent, regionally correlative, and chronostratigraphically significant surface, namely an erosional unconformity characterised in many areas by large incised valleys that was generated above the RST. This unconformity is interpreted as a surface of maximum subaerial erosion generated during the last glacial lowstand (c. 18 ka). Although the base of the RST is associated with a prominent regressive surface of erosion, this is not used as the sequence boundary as it is highly diachronous and difficult to identify and correlate where FRDs are not developed. The previous highstand deposits are limited to subaerial barrier deposits preserved behind several modern Holocene barriers along the coast, while the transgressive systems tract is preserved locally as incised-valley fill deposits beneath the regressive surface of erosion at the base of the RST. Many documented late Pleistocene RSTs have been actively sourced from fluvial systems feeding the shelf and building basinward-thickening, often stacked wedges of FRDs, for which the name allochthonous FRDs is suggested. The Waihi Sequence RST is unusual in that it appears to have been sourced predominantly from reworking of underlying shelf sediments, and thus represents an autochthonous FRD. Autochthonous FRDs are also present on the Forster-Tuncurry shelf in southeast Australia, and may be a common feature in other shelf settings with low subsidence and low sediment supply rates, provided shelf gradients are not too steep, and an underlying source of unconsolidated shelf sediments is available to source FRDs. The preservation potential of such autochthonous FRDs in ancient deposits is probably low given that they are likely to be cannibalised during subsequent sea-level falls