Sedimentation and Stratigraphy of the Rome Formation in East Tennessee

The late Early Cambrian Rome Formation is the oldest formation that is exposed widely across the Valley and Ridge Province. It is brought to the surface by major thrust faults, and in many cases is topographically the highest exposed formation; consequently, the bottom and the top of the Rome are usually missing. Nowhere is a complete section of the Rome formation exposed except in northeast Tennessee. The Rome is a heterogeneous formation of red, maroon, brown and green colored sandstone, siltstone and shale and local beds of gray limestone and dolomite, all of which vary greatly in proportion and distribution throughout the formation. Sandstone and siltstone predominate in the northwestern belts of the Appalachian Valley with lesser amounts of shale and carbonates, while to the southeast shales predominate and carbonates make up approximately half of the formation, thus indicating a western source for the Rome sediments. This is confirmed by elastic ratios, and paleocurrent measurements of cross-bedding and ripple marks in the study area. A striking feature of the Rome Formation is the abundance of primary sedimentary and organic structures. Sedimentary structures which point to a tidal flat type of environment are: mud cracks, halite crystal casts, ripple marks, rain prints, tidal balls, current lamination, ripple lamination, flaser and lenticular bedding. Biogenic sedimentary structures are found throughout the formation of which the most important environmental indicators are Scoyenia (supratidal), Skolithos (beach) and Cruziana (Supratidal to subtidal). Cruziana in the Rome Formation does not fit Seilacher\u27s ichnofacies model in which Cruziana is confined to the subtidal zone. Evidence from the Rome sediments indicates that they were deposited in the following environments: supratidal, mud flat, mixed flat, sand flat, tidal flat gullies, lagoon and oolite shoals. The general coarsening upward in the Rome indicates a general transgressive sequence. The transgressive and regressive phases within the Rome sections can be correlated across strike. Previous studies of the Rome have indicated that the formation is difficult to correlate due to the scarcity of fossils and absence of marker beds. The present study indicates that there are marker beds at the top of the formation and that the Rome can be correlated easily for a distance of 40 km along Pine Ridge and for lesser distances along other ridges. Across strike the formation can be correlated with difficulty over a palinspastic distance of 105 km by utilizing the oolite and Skolithos zones as markers. The Pumpkin Valley Shale which is Middle Cambrian in age is a facies equivalent of the upper Rome, while the top of the Shady Dolomite is a facies equivalent of the lower part of the Rome. Thus the Rome is of late Early Cambrian age in the Appalachian Valley and probably Middle Cambrian in the subsurface in central Tennessee where it lies non-conformably over the Precambrian basement. The sea advanced over the craton in the present position of the Appalachian Valley during Rome time. The craton had been previously peneplained and deeply weathered in a tropical to subtropical climate. The weathered products were transported and deposited in the Rome sea and tidal flats

Interaction of hope and optimism with anxiety and depression in a specific group of cancer survivors: a preliminary study

<p>Abstract</p> <p>Background</p> <p>Anxiety and depression have been identified as a common psychological distress faced by the majority of cancer patients. With the increasing number of cancer cases, increasing demands will be placed on health systems to address effective psychosocial care and therapy. The objective of this study was to assess the possible role of hope and optimism on anxiety and depression. We also wanted to investigate if there is a specific component of hope that could play a role in buffering anxiety and depression amongst cancer patients.</p> <p>Methods</p> <p>A retrospective cross sectional study was conducted in the outpatient station of the Oral and Maxillofacial Surgery at the University of Hong Kong, Hong Kong SAR, PR-China. Fifty patients successfully treated for OC cancer were recruited after their informed consents had been obtained during the review clinic. During their regular follow-up controls in the outpatient clinic the patients compiled the hospital anxiety and depression scale (HADS), hope scale (HS) and the life orientation scale-revised (LOT-R).</p> <p>Results</p> <p>Hope was negatively correlated with depression (<it>r </it>= -.55, <it>p </it>< .001) and anxiety (r = -.38, <it>p </it>< .05). Similar pattern was found between optimism and the latter adjustment outcomes (depression: <it>r </it>= -.55, <it>p </it>< .001; anxiety: <it>r </it>= -.35, <it>p </it>< .05). Regression analyses indentified that both hope and optimism were significant predictors of depression. Hope and optimism had equal association with depression (hope: <it>β </it>= .40 versus optimism: <it>β </it>= .38). Hope and optimism together were significantly predictive of anxiety, whereas neither hope nor optimism alone was significant individual predictors of anxiety.</p> <p>Conclusions</p> <p>Hope and optimism both negatively correlated with patients' level of anxiety and depression. Besides theoretical implications, this study brings forward relevant findings related to developing specific clinical psychological care in the field of oncology that to date has not been researched specifically in the field of oncology. The results of this study will help guide the direction of future prospective studies in the field of oncology. This will contribute significantly to increasing patients quality of life as well enabling health care facilities to provide all cancer patients a more holistic cancer care.</p

Incidence and prevention of osteoradionecrosis after dental extraction in irradiated patients: A systematic review

This systematic review aims to identify and review the best available evidence to answer the clinical question 'What are the incidence and the factors influencing the development of osteoradionecrosis after tooth extraction in irradiated patients?'. A systematic review of published articles on post-irradiation extraction was performed via electronic search of the Medline, Ovid, Embase and Cochrane Library databases. Additional studies were identified by manual reference list search. Evaluation and critical appraisal were done in 3 stages by two independent reviewers and any disagreement was resolved by discussion with a third party. 19 articles were selected for the final analysis. The total incidence of osteoradionecrosis after tooth extraction in irradiated patients was 7%. When extractions were performed in conjunction with prophylactic hyperbaric oxygen, the incidence was 4% while extraction in conjunction with antibiotics gave an incidence of 6%. This systematic review found that while the incidence of osteoradionecrosis after post-irradiation tooth extractions is low, the extraction of mandibular teeth within the radiation field in patients who received a radiation dose higher than 60 Gy represents the highest risk of developing osteoradionecrosis. Based on weak evidence, prophylactic hyperbaric oxygen is effective in reducing the risk of developing osteoradionecrosis after post-radiation extractions. © 2010 International Association of Oral and Maxillofacial Surgeons.link_to_subscribed_fulltex

The impact of case reports in oral and maxillofacial surgery

This review examines the effect of publishing case reports on journal impact factor and future research. All case reports published in the four major English language oral and maxillofacial surgery journals in the two year period, 2007-2008, were searched manually. The citation data of each case report were retrieved from the ISI online database. The number, percentage and mean citations received by case reports and their relation to the 2009 journal impact factor were analysed. Case reports which received more than 5 citations were also identified and all of the citing articles retrieved and analysed. Thirty-one percent of all articles published in major oral and maxillofacial journals in 2007-2008 were case reports. Case reports had a low citation rate with a mean citation of less than 1. There were 38 (7.2%) case reports with more than 5 citations and 30% of the citing articles were also case reports. The publication of case reports negatively affected journal impact factor which correlated directly with the percentage of case reports published within a journal. Case reports reporting recent topics, describing new treatment/diagnosis method and with a literature review were more likely to receive citations. © 2012 International Association of Oral and Maxillofacial Surgeons.link_to_subscribed_fulltex

Risk factors for osteoradionecrosis after head and neck radiation: a systematic review

OBJECTIVE: This systematic review aimed to answer the clinical question, 'What is the current risk of developing osteoradionecrosis of the jaws among irradiated head and neck cancer patients?' STUDY DESIGN: A systematic review of published English-language randomized controlled trials on the outcome of radiation therapy was performed via Medline and Embase databases. Data on osteoradionecrosis/bone toxicity were collected and analyzed. RESULTS: Twenty-two articles reporting on a total of 5,742 patients were selected for final review based on strict eligibility criteria. An estimated 2% of the head and neck-irradiated patients are at risk of developing osteoradionecrosis. Patients receiving adjunctive radiotherapy, accelerated fractionation without dose reduction, and chemoradiotherapy show no increase in osteoradionecrosis risk. Accelerated fractionation with dose reduction is associated with a reduced risk, whereas hyperfractionation shows elevated risk of developing osteoradionecrosis. CONCLUSIONS: The risk of developing osteoradionecrosis among the irradiated head and neck cancer patient has significantly declined in recent years.link_to_subscribed_fulltex