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  1. Periodontal Treatment Reduces Matrix Metalloproteinase Levels in Localized Aggressive Periodontitis

    PubMed Central

    Gonçalves, Patricia Furtado; Huang, Hong; McAninley, Suzanna; Alfant, Barnett; Harrison, Peter; Aukhil, Ikramuddin; Walker, Clay; Shaddox, Luciana Macchion

    2015-01-01

    Background Matrix metalloproteinases (MMPs) are a family of host-derived proteinases reported to mediate multiple functions associated with periodontal destruction and inflammation. We have previously reported high MMP levels in African-American children with localized aggressive periodontitis (LAP). However, little is known about MMP reductions in gingival crevicular fluid (GCF) after therapy. This study aimed to evaluate MMP levels in the GCF following treatment of LAP and to correlate these levels with clinical response. Methods GCF samples were collected from 29 African-American individuals diagnosed with LAP. GCF was collected from one diseased site (pocket depth [PD]>4mm, bleeding on probing [BoP] and clinical attachment level [CAL] ≥2mm) and one healthy site (PD≤3mm, no BoP) from each individual at baseline, 3 and 6 months after periodontal treatment, which consisted of full-mouth SRP and systemic antibiotics. The volume of GCF was controlled using a calibrated gingival fluid meter and levels of MMP-1, 2, 3, 8, 9, 12 and 13 were assessed using fluorometric kits. Results MMP-1, 8, 9 12, and 13 levels were reduced significantly up to 6 months, at which point were comparable with healthy sites. Significant correlations were noted between MMP-2, 3, 8, 9, 12 and 13 levels and % of sites with PD>4mm. MMP-3, 12 and 13 levels also correlated with mean pocket depth of affected sites. Conclusion Treatment of LAP with SRP and systemic antibiotics was effective in reducing the local levels specific MMPs in African-American individuals, which correlated positively with some clinical parameters. PMID:23537121

  2. Orthodontic Management in Aggressive Periodontitis.

    PubMed

    Gyawali, Rajesh; Bhattarai, Bhagabat

    2017-01-01

    Aggressive periodontitis is a type of periodontitis with early onset and rapid progression and mostly affecting young adults who occupy a large percentage of orthodontic patients. The role of the orthodontist is important in screening the disease, making a provisional diagnosis, and referring it to a periodontist for immediate treatment. The orthodontist should be aware of the disease not only before starting the appliance therapy, but also during and after the active mechanotherapy. The orthodontic treatment plan, biomechanics, and appliance system may need to be modified to deal with the teeth having reduced periodontal support. With proper force application and oral hygiene maintenance, orthodontic tooth movement is possible without any deleterious effect in the tooth with reduced bone support. With proper motivation and interdisciplinary approach, orthodontic treatment is possible in patients with controlled aggressive periodontitis.

  3. Orthodontic Management in Aggressive Periodontitis

    PubMed Central

    Bhattarai, Bhagabat

    2017-01-01

    Aggressive periodontitis is a type of periodontitis with early onset and rapid progression and mostly affecting young adults who occupy a large percentage of orthodontic patients. The role of the orthodontist is important in screening the disease, making a provisional diagnosis, and referring it to a periodontist for immediate treatment. The orthodontist should be aware of the disease not only before starting the appliance therapy, but also during and after the active mechanotherapy. The orthodontic treatment plan, biomechanics, and appliance system may need to be modified to deal with the teeth having reduced periodontal support. With proper force application and oral hygiene maintenance, orthodontic tooth movement is possible without any deleterious effect in the tooth with reduced bone support. With proper motivation and interdisciplinary approach, orthodontic treatment is possible in patients with controlled aggressive periodontitis. PMID:28299350

  4. Aggressive periodontitis: The unsolved mystery.

    PubMed

    Clark, Danielle; Febbraio, Maria; Levin, Liran

    2017-01-01

    Aggressive periodontal disease is an oral health mystery. Our current understanding of this disease is that specific bacteria invade the oral cavity and the host reacts with an inflammatory response leading to mass destruction of the alveolar bone. Aggressive periodontal disease is typically observed in a population under the age of 30 and occurs so rapidly that it is difficult to treat. Unfortunately, the consequence of this disease frequently involves tooth extractions. As a result, the aftermath is chewing disability and damage to self-esteem due to an altered self-image. Furthermore, patients are encumbered by frequent dental appointments which have an economic impact in regards to both personal financial strain and absent days in the workplace. Aggressive periodontal disease has a tremendous effect on patients' overall quality of life and needs to be investigated more extensively in order to develop methods for earlier definitive diagnosis and effective treatments. One of the mysteries of aggressive periodontal disease is the relatively nominal amount of plaque present on the tooth surface in relation to the large amount of bone loss. There seems to be a hidden factor that lies between the response by the patient's immune system and the bacterial threat that is present. A better mechanistic understanding of this disease is essential to provide meaningful care and better outcomes for patients.

  5. Trends in Susceptibility to Aggressive Periodontal Disease

    PubMed Central

    Shahabuddin, Nishat; Boesze-Battaglia, Kathleen; Lally, Edward T

    2016-01-01

    Aggregatibacter actinomycetemcomitans is a gram-negative microbe involved in periodontitis. Strains with varying degrees of virulence have been identified, in healthy and periodontally compromised individuals alike. Hosts mount differential immune responses to its various serotypes and virulence factors. Studies have explored host immune response in terms of antibody titers, leukocyte responses, and specific inflammatory mediators, questioning the ways in which the infectious microorganism survives. This mini-review will identify the key themes in immune response patterns of individuals both affected by and free from aggressive periodontal disease, thereby using it to understand various forms of periodontitis. PMID:28008419

  6. Isolated cleft lip with generalized aggressive periodontitis: A rare entity

    PubMed Central

    Metgud, Renuka; Kumar, Ajay; Bhat, Kishore

    2015-01-01

    Oro-facial clefts are one of the most common birth defects and may be associated with other genetic anomalies. Aggressive periodontitis is a rare condition that progresses rapidly, but affects only a small percentage of the population. Most of the cases of aggressive periodontitis are familial. Even though, literature has documented the association of various genetic disorders with aggressive periodontitis, the aggressive periodontitis in patients with isolated cleft lip (CL) have never been addressed. Here, we report a rare case of isolated CL with generalized aggressive periodontitis. The concomitant presentation of isolated CL with aggressive periodontitis in an individual has clinical significance for multi-disciplinary care. PMID:25810600

  7. Collaborative management of a young patient with generalized aggressive periodontitis.

    PubMed

    Sivakumar, Arunachalam; Raju, M A K V; Sunny, James; Cyriac, Rajesh; Bhat, Subraya; Mohandas, Ashil A; Divya, Beemavarapu

    2014-01-01

    What are the orthodontic treatment possibilities, limitations and risks inherent in patients with periodontal disorders, particularly active periodontal disease? This case report describes the interface between orthodontics, periodontics and restorative dentistry in the management of a 25-year-old young man with generalized aggressive periodontitis.

  8. Prosthodontic rehabilitation of a patient with aggressive periodontitis

    PubMed Central

    Livingstone, David; Murthy, Varsha; Reddy, Vineela Katam; Pillai, Ajay

    2015-01-01

    Aggressive periodontitis previously termed as juvenile periodontitis is characterised by rapid destruction of the periodontium at a relatively young age. Rehabilitation of these patients is often challenging and difficult. Controlling the disease and restoring periodontal health is essential for successful prosthodontic rehabilitation. This clinical report describes an interdisciplinary approach in the rehabilitation of a young adult patient with generalised aggressive periodontitis. Treatment objectives included plaque control, prevention of further attachment loss, reduction/elimination of pockets, and prosthetic rehabilitation to enhance aesthetics and restore masticatory function. One year recall evaluation revealed stable periodontal support with no further loss of attachment and no other complications. PMID:25743856

  9. Amelogenesis imperfecta and localised aggressive periodontitis: A rare clinical entity.

    PubMed

    Gundannavar, Gayatri; Rosh, Radhika M; Chandrasekaran, Shoba; Hussain, Ahad M

    2013-01-01

    This case report presents two female patients whose chief complaint was discoloration of teeth. On careful clinical examination it was found that the patients had features of amelogenesis imperfecta and localised aggressive periodontitis. This article will give an insight of clinical and radiographic features of amelogenesis imperfecta with localised aggressive periodontitis, which is a rare clinical entity.

  10. Parameter on aggressive periodontitis. American Academy of Periodontology.

    PubMed

    2000-05-01

    The American Academy of Periodontology has developed the following parameter on the treatment of aggressive periodontitis. Patients should be informed of the disease process, therapeutic alternatives, potential complications, expected results, and their responsibility in treatment. Consequences of no treatment should be explained. Failure to treat aggressive periodontitis appropriately can result in progressive and often rapid loss of periodontal supporting tissues. This may have an adverse effect upon prognosis and could result in tooth loss. Given this information, patients (or their parents or guardians, as appropriate) should then be able to make informed decisions regarding their periodontal therapy.

  11. Treatment of a Periodontic-Endodontic Lesion in a Patient with Aggressive Periodontitis

    PubMed Central

    2016-01-01

    Case Description. This case report describes the successful management of a left mandibular first molar with a combined periodontic-endodontic lesion in a 35-year-old Caucasian woman with aggressive periodontitis using a concerted approach including endodontic treatment, periodontal therapy, and a periodontal regenerative procedure using an enamel matrix derivate. In spite of anticipated poor prognosis, the tooth lesion healed. This case report also discusses the rationale behind different treatment interventions. Practical Implication. Periodontic-endodontic lesions can be successfully treated if dental professionals follow a concerted treatment protocol that integrates endodontic and periodontic specialties. General dentists can be the gatekeepers in managing these cases. PMID:27418983

  12. Molecular Differences between Chronic and Aggressive Periodontitis

    PubMed Central

    Kebschull, M.; Guarnieri, P.; Demmer, R.T.; Boulesteix, A.L.; Pavlidis, P.; Papapanou, P.N.

    2013-01-01

    The 2 major forms of periodontitis, chronic (CP) and aggressive (AgP), do not display sufficiently distinct histopathological characteristics or microbiological/immunological features. We used molecular profiling to explore biological differences between CP and AgP and subsequently carried out supervised classification using machine-learning algorithms including an internal validation. We used whole-genome gene expression profiles from 310 ‘healthy’ or ‘diseased’ gingival tissue biopsies from 120 systemically healthy non-smokers, 65 with CP and 55 with AgP, each contributing with ≥ 2 ‘diseased’ gingival papillae (n = 241; with bleeding-on-probing, probing depth ≥ 4 mm, and clinical attachment loss ≥ 3 mm), and, when available, a ‘healthy’ papilla (n = 69; no bleeding-on-probing, probing depth ≤ 4 mm, and clinical attachment loss ≤ 4 mm). Our analyses revealed limited differences between the gingival tissue transcriptional profiles of AgP and CP, with genes related to immune responses, apoptosis, and signal transduction overexpressed in AgP, and genes related to epithelial integrity and metabolism overexpressed in CP. Different classifying algorithms discriminated CP from AgP with an area under the curve ranging from 0.63 to 0.99. The small differences in gene expression and the highly variable classifier performance suggest limited dissimilarities between established AgP and CP lesions. Future analyses may facilitate the development of a novel, ‘intrinsic’ classification of periodontitis based on molecular profiling. PMID:24122488

  13. From alveolar diffuse atrophy to aggressive periodontitis: a brief history.

    PubMed

    Guzeldemir, Esra; Toygar, Hilal Uslu

    2006-01-01

    Technologic advances in mechanics, electronics, physics, chemistry, and computer science have contributed to advances in dental medicine. Periodontology is not only a clinical science but is also directly related to the basic sciences. Research is conducted in laboratories rather than in clinics now. During the last century, aggressive periodontitis has received attention from numerous researchers because of its multifactorial features. This paper explores the long scientific journey of aggressive periodontitis, beginning with its first definition as alveolar diffuse atrophy. Perhaps in the future, "alveolar diffuse atrophy" will be referred to by another name or term. However, this journey will never end.

  14. Combined periodontal and orthodontic treatment in a patient with aggressive periodontitis: a 9-year follow-up report.

    PubMed

    Closs, Luciane Quadrado; Gomes, Sabrina Carvalho; Oppermann, Rui Vicente; Bertoglio, Vivian

    2010-01-01

    A combined periodontal and orthodontic treatment demands a detailed evaluation in both specialties, particularly when the periodontium is reduced. This is especially true for adult patients, but young patients can also suffer from advanced periodontitis. This article describes combined periodontal and orthodontic therapy in a young patient with severe localized and aggressive periodontitis, tooth crown abnormalities, and missing maxillary second premolars. Periodontal treatment was carried out. Once attachment gain and bone stability were confirmed, orthodontic therapy commenced. It lasted 32 months, during which segmented mechanics and only light forces were used. The result of this intervention was satisfactory, and long-term stability (9 years) with periodontal maintenance was achieved.

  15. Occurrence of aggressive periodontitis in patients at a dental school in southern Brazil.

    PubMed

    Hermes, Chirley Roberta; Baumhardt, Simone Glesse; Rösing, Cassiano Kuchenbecker

    2013-01-01

    Aggressive periodontitis is a rare, severe and rapidly progressing periodontal disease. Early diagnosis is of utmost importance for establishing treatment in order to stop periodontal destruction and prevent tooth loss. The aim of this study is to describe the occurrence of aggressive periodontitis in patients at a Dental School in Brazil by means of a cross-sectional study. First, records from patients aged 15-36 years were consecutively scrutinized. Patients should not have systemic diseases. The search went up to 383 valid records. By means of periapical radiographs, the distance between the cement-enamel junction and the bone crest was measured. Records in which there was severe bone loss or periodontal destruction incompatible with the age of the patient were selected. Patients with bone loss > or = 3mm were called to answer a questionnaire and undergo periodontal examination, in order to confirm or dismiss the diagnosis of aggressive periodontitis. From a total 383 records, 55.1% (211) were female and 44.9% (172) were male. In 3.9% (15) of the records, presumed diagnosis was aggressive periodontitis, and 12 out of those 15 eligible patients (80%) came in for clinical examination and confirmation or dismissal of the diagnosis. Aggressive periodontitis was diagnosed in 7 patients, corresponding to 1.8% of the total. Of these, 4 (1% of the total) presented generalized aggressive periodontitis and 3 (0.8% of the total) presented localized aggressive periodontitis. In 5 patients (1.3%) chronic periodontitis was diagnosed. It may be concluded, within the limits of the study, that aggressive periodontitis at this Dental School is compatible with world prevalence values, suggesting the need for periodontal diagnosis as from adolescence, considering the possible damage caused by this disease.

  16. Idiopathic gingival enlargement associated with generalized aggressive periodontitis in a 19-year-old female

    PubMed Central

    Shetty, Arvind; Gupta, Neha; Shetty, Devanand; Kadakia, Rukshit

    2014-01-01

    Gingival enlargement, one of the manifestations of gingival and periodontal disease, is also known as gingival overgrowth. Idiopathic gingival enlargement is a rare gingival overgrowth, which is of an undetermined cause. This unknown etiology has now been linked to specific genes and idiopathic gingival enlargement is at times referred to as hereditary gingival enlargement. This condition is a benign, slow growing proliferation of gingival tissues. Aggressive periodontitis is the rapid form of periodontal disease which is characterized by extensive periodontal tissue destruction, increased host-susceptibility toward periodontal disease progress and a genetic predilection toward disease occurrence. We present a rare case of idiopathic gingival fibromatosis associated with generalized aggressive periodontitis in a young female. The patient presented with classic clinical and radiographic presentation associated with gingival enlargement and aggressive periodontitis. The diagnosis was then confirmed by histopathological and neutrophil functions tests. PMID:24872638

  17. Aggressive Periodontitis: microbes and host response, who to blame?

    PubMed Central

    Nibali, Luigi

    2015-01-01

    A paradigm shift several decades ago elucidated that aggressive periodontitis (AgP) was not a degenerative disorder but a rapid progressive form of plaque-induced inflammatory periodontal disease. Ensuing years of research have led to linkage analysis identification of specific genetic defects responsible for AgP in some families and to the finding that subgingival detection of A. actinomycet-emcomitans JP2 clone is a predictive factor for disease onset and progression. However, rather disappointingly, these ‘proven’ risk factors are only detected in a small subset of AgP cases. Recent advances are leading to a new paradigm shift, with the realization that genetically-driven dysbiotic changes in the subgingival microbiota may predispose to a cascade of events leading to the rapid periodontal tissue destruction seen in AgP. This review tries to dissect the existing literature on the host response-microbial axis of AgP and to propose possible pathogenic pathways in line with current theories. PMID:25654663

  18. Relationships between subgingival microbiota and GCF biomarkers in generalized aggressive periodontitis

    PubMed Central

    Teles, R.P.; Gursky, L.C.; Faveri, M.; Rosa, E.A.; Teles, F. R. F.; Feres, M.; Socransky, S.S.; Haffajee, A.D.

    2010-01-01

    Aim To examine relationships between subgingival biofilm composition and levels of gingival crevicular fluid (GCF) cytokines in periodontal health and generalized aggressive periodontitis (GAP). Materials and methods Periodontal parameters were measured in 25 periodontally healthy and 31 GAP subjects. Subgingival plaque and GCF samples were obtained from 14 sites from each subject. 40 subgingival taxa were quantified using checkerboard DNA-DNA hybridization and the concentrations of 8 GCF cytokines measured using Luminex. Cluster analysis was used to define sites with similar subgingival microbiotas in each clinical group. Significance of differences in clinical, microbiological and immunological parameters among clusters was determined using the Kruskal-Wallis test. Results GAP subjects had statistically significantly higher GCF levels of interleukin-1β (IL-1β) (p<0.001), granulocyte-macrophage colony-stimulating factor (GM-CSF) (p<0.01), and IL-1β/IL-10 ratio (p<0.001) and higher proportions of Red and Orange complex species than periodontally healthy subjects. There were no statistically significant differences in the mean proportion of cytokines among clusters in the periodontally healthy subjects, while the ratio IL-1β/IL-10 (p<0.05) differed significantly among clusters in the aggressive periodontitis group. Conclusions Different subgingival biofilm profiles are associated with distinct patterns of GCF cytokine expression. Aggressive periodontitis subjects were characterized by a higher IL-1β/IL-10 ratio than periodontally healthy subjects, suggesting an imbalance between pro- and anti-inflammatory cytokines in aggressive periodontitis. PMID:20447254

  19. A consortium of Aggregatibacter actinomycetemcomitans, Streptococcus parasanguinis, and Filifactor alocis is present in sites prior to bone loss in a longitudinal study of localized aggressive periodontitis.

    PubMed

    Fine, Daniel H; Markowitz, Kenneth; Fairlie, Karen; Tischio-Bereski, Debbie; Ferrendiz, Javier; Furgang, David; Paster, Bruce J; Dewhirst, Floyd E

    2013-09-01

    Aggregatibacter actinomycetemcomitans-induced localized aggressive periodontitis (LAP) in African-American adolescents has been documented but is poorly understood. Two thousand fifty-eight adolescents aged 11 to 17 years were screened for their periodontal status and the presence of A. actinomycetemcomitans in their oral cavity. Seventy-one A. actinomycetemcomitans-negative and 63 A. actinomycetemcomitans-positive periodontally healthy subjects were enrolled, sampled, examined, and radiographed yearly for 3 years. Gingival and periodontal pocket depth and attachment levels were recorded. Disease presentation was characterized by bone loss (BL). Subgingival sites were sampled every 6 months to assess (i) the role of A. actinomycetemcomitans in BL and (ii) the association of A. actinomycetemcomitans and other microbes in their relationships to BL. Sixteen of 63 subjects with A. actinomycetemcomitans developed BL (the other 47 subjects with A. actinomycetemcomitans had no BL). No A. actinomycetemcomitans-negative subjects developed BL. Human oral microbe identification microarray (HOMIM) was used for subgingival microbial assessment. On a subject level, pooled data from A. actinomycetemcomitans-positive subjects who remained healthy had higher prevalences of Streptococcus and Actinomyces species, while A. actinomycetemcomitans-positive subjects with BL had higher prevalences of Parvimonas micra, Filifactor alocis, A. actinomycetemcomitans, and Peptostreptococcus sp. human oral taxon 113 (HOT-113). At vulnerable sites, A. actinomycetemcomitans, Streptococcus parasanguinis, and F. alocis levels were elevated prior to BL. In cases where the three-organism consortium (versus A. actinomycetemcomitans alone) was detected, the specificity for detecting sites of future BL increased from 62% to 99%, with a sensitivity of 89%. We conclude that detecting the presence of A. actinomycetemcomitans, S. parasanguinis, and F. alocis together indicates sites of future BL in LAP. A

  20. A Consortium of Aggregatibacter actinomycetemcomitans, Streptococcus parasanguinis, and Filifactor alocis Is Present in Sites Prior to Bone Loss in a Longitudinal Study of Localized Aggressive Periodontitis

    PubMed Central

    Markowitz, Kenneth; Fairlie, Karen; Tischio-Bereski, Debbie; Ferrendiz, Javier; Furgang, David; Paster, Bruce J.; Dewhirst, Floyd E.

    2013-01-01

    Aggregatibacter actinomycetemcomitans-induced localized aggressive periodontitis (LAP) in African-American adolescents has been documented but is poorly understood. Two thousand fifty-eight adolescents aged 11 to 17 years were screened for their periodontal status and the presence of A. actinomycetemcomitans in their oral cavity. Seventy-one A. actinomycetemcomitans-negative and 63 A. actinomycetemcomitans-positive periodontally healthy subjects were enrolled, sampled, examined, and radiographed yearly for 3 years. Gingival and periodontal pocket depth and attachment levels were recorded. Disease presentation was characterized by bone loss (BL). Subgingival sites were sampled every 6 months to assess (i) the role of A. actinomycetemcomitans in BL and (ii) the association of A. actinomycetemcomitans and other microbes in their relationships to BL. Sixteen of 63 subjects with A. actinomycetemcomitans developed BL (the other 47 subjects with A. actinomycetemcomitans had no BL). No A. actinomycetemcomitans-negative subjects developed BL. Human oral microbe identification microarray (HOMIM) was used for subgingival microbial assessment. On a subject level, pooled data from A. actinomycetemcomitans-positive subjects who remained healthy had higher prevalences of Streptococcus and Actinomyces species, while A. actinomycetemcomitans-positive subjects with BL had higher prevalences of Parvimonas micra, Filifactor alocis, A. actinomycetemcomitans, and Peptostreptococcus sp. human oral taxon 113 (HOT-113). At vulnerable sites, A. actinomycetemcomitans, Streptococcus parasanguinis, and F. alocis levels were elevated prior to BL. In cases where the three-organism consortium (versus A. actinomycetemcomitans alone) was detected, the specificity for detecting sites of future BL increased from 62% to 99%, with a sensitivity of 89%. We conclude that detecting the presence of A. actinomycetemcomitans, S. parasanguinis, and F. alocis together indicates sites of future BL in LAP. A

  1. Localized severe aggressive periodontitis. Disease progression and tooth preservation: a short case report over 14 years.

    PubMed

    Pelka, Matthias; Petschelt, Anselm

    2009-04-01

    A case of a 31-year-old female with aggressive periodontitis over 14 years is presented. From 1993 to 2000, no periodontal therapy occurred; disease development and progression could be reconstructed upon radiographic findings. In 2000, full-mouth disinfection therapy and antibiotic therapy was performed, as well as regenerative surgical treatments. Seven years after surgical treatment, stable periodontal conditions and clear bone regeneration in the surgical areas was evident.

  2. Subgingival microbial profiles of Sudanese patients with aggressive periodontitis

    PubMed Central

    Elabdeen, H. R. Z.; Mustafa, M.; Hasturk, H.; Klepac-Ceraj, V.; Ali, R. W.; Paster, B. J.; Dyke, T. Van; Bolstad, A. I.

    2015-01-01

    Background and Objective Aggressive periodontitis (AgP) is prevalent and shows a rapid course in African individuals. Although a strong focus has been placed on Aggregatibacter actinomycetemcomitans, new methods support the existence of a complex subgingival microflora in AgP. The purpose of the present study was to map the subgingival microbiota as well as explore the presence of A. actinomycetemcomitans and the JP2 clone in a group of Sudanese individuals with AgP, using different analytical methods. Material and Methods A study population consisting of 19 patients with AgP was recruited from patients seeking treatment at University of Science and Technology (UST) in Khartoum. Fifteen healthy subjects were included as controls. Plaque samples were analyzed for 272 taxa using human oral microbe identification microarrays and for 26 periodontal taxa using DNA-DNA hybridization checkerboard. Conventional polymerase chain reaction (PCR) was applied for the detection of A. actinomycetemcomitans and the JP2 clone in plaque. Saliva from patients with AgP was analyzed using quantitative PCR (qPCR) for the detection of A. actinomycetemcomitans. Results Eubacterium yurii was detected more frequently in patients with AgP than in controls, and E. nodatum was found in patients with AgP only. A. actinomycetemcomitans was found in plaque samples of two (12%) patients by human oral microbe identification microarrays and in five (29%) patients with AgP by conventional PCR, as well as in six (32%) of the AgP saliva samples by qPCR. The JP2 clone was identified in only one patient. Conclusion The classical periodontal pathogens were not present in high amounts in AgP in the population studied here. Species of Eubacterium, which are not typically associated with AgP, were often detected in individuals with disease. Using laboratory methods with different sensitivities and detection levels allowed identification of variances in microbial communities. The findings reported in this

  3. Gingival Crevicular Fluid and Salivary Periostin Levels in Non-Smoker Subjects With Chronic and Aggressive Periodontitis : Periostin Levels in Chronic and Aggressive Periodontitis.

    PubMed

    Aral, Cüneyt A; Köseoğlu, Serhat; Sağlam, Mehmet; Pekbağrıyanık, Tuğba; Savran, Levent

    2016-06-01

    Periostin, an extracellular matrix protein functioning as an important structural mediator and adhesion molecule, has been shown to be an important regulator of connective tissue integrity. This study aimed to evaluate the levels of periostin in chronic periodontitis (CP) and aggressive periodontitis (AgP) compared to non-periodontitis (NP). Individuals were submitted to gingival crevicular fluid (GCF) and saliva sampling. Periodontal examination consisted of plaque index (PI), gingival index (GI), probing depth (PD), bleeding on probing (BOP), and clinical attachment level (CAL) measurements. Assays for periostin were performed by an enzyme-linked immunosorbent assay. Periodontitis patients presented more severe clinical indices compared to the NP group (p < 0.001). The mean GCF level of periostin was lowest in the AgP group as compared to the other groups and was lower in the CP group as compared to the NP group (p < 0.001). Increased levels of periostin were observed in the saliva of patients with AgP as compared to the CP and NP groups (p < 0.05). There was a negative relationship between GCF periostin levels and clinical parameters (p < 0.01), whereas a positive correlation was observed between salivary periostin levels and full-mouth GI and CAL scores (p < 0.01). To our knowledge, this is the first report investigating periostin levels in GCF and saliva in aggressive periodontitis. The results suggest that subjects with CP and AgP exhibit a different periostin profile. Periostin in GCF may have a protective role against periodontal disease. Furthermore, salivary periostin concentrations may have a promising diagnostic potential for the aggressive forms of periodontal disease.

  4. The novel role of HtrA1 in gingivitis, chronic and aggressive periodontitis.

    PubMed

    Lorenzi, Teresa; Niţulescu, Elena Annabel; Zizzi, Antonio; Lorenzi, Maria; Paolinelli, Francesca; Aspriello, Simone Domenico; Baniţă, Monica; Crăiţoiu, Stefania; Goteri, Gaia; Barbatelli, Giorgio; Lombardi, Tommaso; Di Felice, Roberto; Marzioni, Daniela; Rubini, Corrado; Castellucci, Mario

    2014-01-01

    Proteolytic tissue degradation is a typical phenomenon in inflammatory periodontal diseases. HtrA1 (High temperature requirement A 1) has a serine protease activity and is able to degrade fibronectin whose fragments induce the expression and secretion of several matrix metalloproteinases (MMPs). The aim of this study was to investigate for the first time if HtrA1 has a role in gingivitis and in generalized forms of chronic and aggressive periodontitis. Expression of HtrA1 was investigated in 16 clinically healthy gingiva, 16 gingivitis, 14 generalized chronic periodontitis and 10 generalized aggressive periodontitis by immunohistochemistry and real-time PCR. Statistical comparisons were performed by the Kruskall-Wallis test. Significantly higher levels of HtrA1 mRNA and protein expression were observed in pathological respect to healthy tissues. In particular, we detected an increase of plasma cell HtrA1 immunostaining from gingivitis to chronic and aggressive periodontitis, with the higher intensity in aggressive disease. In addition, we observed the presence of HtrA1 in normal and pathological epithelium, with an increased expression, particularly in its superficial layer, associated with increasingly severe forms of periodontal disease. We can affirm that HtrA1 expression in plasma cells could be correlated with the destruction of pathological periodontal tissue, probably due to its ability to trigger the overproduction of MMPs and to increase the inflammatory mediators TNF-α and IL-1β by inhibition of TGF-β. Moreover, epithelial HtrA1 immunostaining suggests a participation of the molecule in the host inflammatory immune responses necessary for the control of periodontal infection.

  5. Interdisciplinary orthodontic treatment for a patient with generalized aggressive periodontitis: Assessment of IgG antibodies to identify type of periodontitis and correct timing of treatment.

    PubMed

    Ishihara, Yoshihito; Tomikawa, Kazuya; Deguchi, Toru; Honjo, Tadashi; Suzuki, Koji; Kono, Takayuki; Kuboki, Takuo; Kamioka, Hiroshi; Takashiba, Shogo; Yamashiro, Takashi

    2015-06-01

    Aggressive periodontitis is a great challenge to clinicians when providing orthodontic treatment because of the potential for progression of periodontal disease. In this article, we report the successful comprehensive orthodontic treatment of bimaxillary protrusion and severe crowding in an adult with generalized aggressive periodontitis. A woman, aged 22 years 7 months, with a chief complaint of incisal crowding was diagnosed with a skeletal Class I malocclusion associated with severe anterior crowding, possibly worsened by generalized aggressive periodontitis. In addition to a periodontal examination, a blood IgG antibody titer analysis and microbiologic examination for periodontal pathogens were used to diagnose the type of periodontal disease and determine the proper timing to initiate orthodontic treatment. The total active treatment period was 28 months, followed by periodontal prostheses and regeneration therapy. Consequently, satisfactory facial profile, occlusion, and periodontal health were maintained for at least 36 months. These results indicate that efficient screening is important for providing successful orthodontic treatment in patients with advanced periodontal disease. This report also demonstrates the diagnostic importance of blood IgG antibody titer assays and microbiologic examinations to detect periodontal pathogens.

  6. Implant Rehabilitation in Advanced Generalized Aggressive Periodontitis: A Case Report and Literature Review

    PubMed Central

    Rasaeipour, Sasan; Siadat, Hakimeh; Rasouli, Amiralireza; Sajedinejadd, Neda

    2015-01-01

    Dental implants have provided exceptional rehabilitative options for edentulous and partially edentulous patients. However, as more implants come into play, the more the clinicians come across problems where specific considerations must be taken into account to meet expectations. The Toronto Bridge is a treatment modality proposed for restoring several teeth lost in patients with increased crown height (interarch) space. Herein, we applied the Toronto Bridge to rehabilitate a patient with generalized aggressive periodontitis; this article suggests that an implant-supported Toronto Bridge can be a reliable and acceptable treatment modality for patients suffering from tooth loss and vertical bone loss as the result of generalized aggressive periodontal disease. PMID:27123022

  7. Correlation of Aggregatibacter actinomycetemcomitans Detection with Clinical/Immunoinflammatory Profile of Localized Aggressive Periodontitis Using a 16S rRNA Microarray Method: A Cross-Sectional Study

    PubMed Central

    Gonçalves, Patricia F.; Klepac-Ceraj, Vanja; Huang, Hong; Paster, Bruce J.; Aukhil, Ikramuddin; Wallet, Shannon M.; Shaddox, Luciana M.

    2013-01-01

    Objective The objective of this study was to determine whether the detection of Aggregatibacter actinomycetemcomitans (Aa) correlates with the clinical and immunoinflammatory profile of Localized Aggressive Periodontitis (LAP), as determined by by 16S rRNA gene-based microarray. Subjects and Methods Subgingival plaque samples from the deepest diseased site of 30 LAP patients [PD ≥ 5 mm, BoP and bone loss] were analyzed by 16S rRNA gene-based microarrays. Gingival crevicular fluid (GCF) samples were analyzed for 14 cyto/chemokines. Peripheral blood was obtained and stimulated in vitro with P.gingivalis and E.coli to evaluate inflammatory response profiles. Plasma lipopolysaccharide (LPS) levels were also measured. Results Aa was detected in 56% of LAP patients and was shown to be an indicator for different bacterial community structures (p<0.01). Elevated levels of pro-inflammatory cyto/chemokines were detected in LPS-stimulated blood samples in both Aa-detected and Aa-non-detected groups (p>0.05). Clinical parameters and serum LPS levels were similar between groups. However, Aa-non-detected GCF contained higher concentration of IL-8 than Aa-detected sites (p<0.05). TNFα and IL1β were elevated upon E.coli LPS stimulation of peripheral blood cells derived from patients with Aa-detected sites. Conclusions Our findings demonstrate that the detection of Aa in LAP affected sites, did not correlate with clinical severity of the disease at the time of sampling in this cross-sectional study, although it did associate with lower local levels of IL-8, a different subgingival bacterial profile and elevated LPS-induced levels of TNFα and IL1β. PMID:24376864

  8. Association of Interleukin-17 polymorphism (-197G/A) in chronic and localized aggressive periodontitis.

    PubMed

    Chaudhari, Harshal Liladhar; Warad, Shivaraj; Ashok, Nipun; Baroudi, Kusai; Tarakji, Bassel

    2016-01-01

    Interleukin 17(IL-17) is a pro-inflammatory cytokine produced mainly by Th17 cells. The present study was undertaken to investigate a possible association between IL-17 A genetic polymorphism at (-197A/G) and susceptibility to chronic and localized aggressive periodontitis (LAgP) in an Indian population. The study was carried out on 105 subjects, which included 35 LAgP patients, 35 chronic periodontitis patients and 35 healthy controls. Blood samples were drawn from the subjects and analyzed for IL-17 genetic polymorphism at (-197A/G), by using the polymerase chain reaction-restriction fragment length polymorphism method. A statistically significant difference was seen in the genotype distribution among chronic periodontitis patients, LAgP patients and healthy subjects. There was a significant difference in the distribution of alleles among chronic periodontitis patients, LAgP patients and healthy subjects. The odds ratio for A allele versus G allele was 5.1 between chronic periodontitis patients and healthy controls, and 5.1 between LAgp patients and healthy controls. Our study concluded that IL-17 A gene polymorphism at (-197A/G) is linked to chronic periodontitis and LAgP in Indian population. The presence of allele A in the IL-17 gene polymorphism (-197A/G) can be considered a risk factor for chronic periodontitis and LAgP.

  9. Congenital adrenal hyperplasia with localized aggressive periodontitis and amelogenesis imperfecta.

    PubMed

    Ajlan, Sumaiah Abdulbaqi

    2015-11-01

    Congenital adrenal hyperplasia (CAH) is an inherited medical condition that implies defects in steroid biosynthesis. The dental findings of a female patient with CAH are reported. The patient suffered from severe periodontal tissue destruction, obvious enamel defects, as well as some occlusal problems. The management approach is presented and the possibility of interrelation of her dental findings with her medical condition is discussed.

  10. Maintenance periodontal therapy after systemic antibiotic and regenerative therapy of generalized aggressive periodontitis. A case report with 10-year follow-up.

    PubMed

    Siqueira, Sergio Júnior; Ribeiro, Fernanda Vieira; Villalpando, Karina Teixeira; Cirano, Fabiano Ribeiro; Pimentel, Suzana Peres

    2015-05-01

    Aggressive periodontitis (AgP) is an inflammatory disease characterized by rapid attachment loss and bone destruction. This case report presents the 10-year results in a subject with generalized AgP treated by a regenerative periodontal therapeutic approach and the adjunctive use of antibiotics, following a systematic maintenance periodontal therapy. The use of enamel matrix derivatives (EMD) and adjunctive antibiotic therapy to treat AgP yielded improvements in clinical parameters and radiographic bony fill. This combined therapeutic approach following a systematic supportive periodontal therapy supports the long-term maintenance of teeth with previous advanced periodontal defects, demonstrating successful stability after 10-years follow-up. Clinical Relevance: The combined treatment protocol using EMD plus adjunctive antibiotic therapy, associated with a systematic supportive periodontal therapy, benefits the long-term maintenance of teeth with previous advanced periodontal defects in subjects presenting AgP, supporting this approach as an alternative in the treatment of AgP.

  11. Tannerella forsythia and the HLA-DQB1 allele are associated with susceptibility to periodontal disease in Japanese adolescents.

    PubMed

    Shimomura-Kuroki, Junko; Yamashita, Kie; Shimooka, Shohachi

    2009-01-01

    Periodontal disease is a multiple factor disease caused by genetic factors, environmental factors, and periodontal bacteria (periodontal pathogens). The present study aimed to elucidate the risk factors for periodontal disease in Japanese adolescents. Subjects (11-16 years old) were classified into three groups: localized aggressive periodontitis (LAP), periodontal attachment loss (PAL), and periodontally healthy (PH) groups. Genomic DNA isolated from the buccal mucosa was used for single-nucleotide polymorphism analyses of the candidate genes (interleukin-1alpha-889; interleukin-1alpha +4845; interleukin-1beta +3954; an immunoglobulin G Fc gamma receptor, FcgammaRIIa-R/H131; and a human leukocyte antigen class II allele, HLA-DQB1) of aggressive periodontitis. Subgingival plaque samples obtained from the same subjects were used for 16S rRNAbased polymerase chain reaction analysis of five important periodontal pathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola, and Tannerella forsythia). Tannerella forsythia was detected in the deepest periodontal pockets in all subjects in the LAP and PAL groups. The prevalence of an atypical BamHI restriction site in HLA-DQB1 of the LAP group was significantly higher than that in the PH and PAL groups. Furthermore, all subjects who had the atypical BamHI restriction site in HLA-DQB1 had T. forsythia infection. These results suggested that T. forsythia is associated with periodontal disease in Japanese adolescents and also suggested that HLA-DQB1 is related to LAP and is associated with T. forsythia infection.

  12. Comparison of Cone Beam Computed Tomography-Derived Alveolar Bone Density Between Subjects with and without Aggressive Periodontitis

    PubMed Central

    Al-Zahrani, Mohammad S.; Elfirt, Eman Y.; Al-Ahmari, Manea M.; Yamany, Ibrahim A.; Alabdulkarim, Maher A.

    2017-01-01

    Introduction Understanding the changes in bone density of patients affected by aggressive periodontitis could be useful in early disease detection and proper treatment planning. Aim The aim of this study was to compare alveolar bone density in patients affected with aggressive periodontitis and periodontally healthy individuals using Cone Beam Computed Tomography (CBCT). Materials and Methods This cross-sectional study was conducted on 20 patients with a confirmed diagnosis of aggressive periodontitis. Twenty periodontally healthy patients attending the dental clinics for implant placement or extraction of impacted third molars served as controls. Alveolar bone density was measured using CBCT scanning. Comparisons between aggressive periodontitis group and controls for age and alveolar bone density of the anterior and posterior regions were performed using an independent sample t-test. Multivariable linear regression models were also performed. Results The differences between groups in regard to age, anterior and posterior alveolar bone density was not statistically significant (p<0.05). In the posterior region, the multivariable regression model showed that bone density was not associated with age, gender or the study groups. Whereas, in the anterior region, patient’s age was found to be significantly associated with bone density, p=0.014. Conclusion Alveolar bone density as measured by CBCT in aggressive periodontitis patients was not different from periodontally healthy individuals. Further studies are needed to confirm these findings. PMID:28274060

  13. Systemic moxifloxacin vs amoxicillin/metronidazole adjunct to non-surgical treatment in generalized aggressive periodontitis

    PubMed Central

    Gurgan, Cem-Abdulkadir

    2015-01-01

    Background The objective of this randomized clinical study was to evaluate the effect of systemic administration of moxifloxacin compared to amoxicillin and metronidazole, combined with non-surgical treatment in patients with generalized aggressive periodontitis (GAgP) in a 6-month follow-up. Material and Methods A total of 39 systemically healthy patients with GAgP were evaluated in this randomized clinical trial. Periodontal parameters were recorded at the baseline during the 1st, 3rd and 6th month. Patients received either 400 mg of moxifloxacin per os once daily or 500 mg of metronidazole and 500 mg amoxicillin per os three times daily for 7 days consecutively. Results No significant differences between groups were found in any parameters at the baseline. Both groups led to a statistically significant decrease in all clinical periodontal parameters compared to the baseline (PI, p<0.001 and GI, PD, BOP, CAL, p<0.01). There were no differences between the 1st and 3rd months or the 3rd and 6th months for clinical parameters in the groups. Also, no intergroup difference was observed in any parameters at any time, except the gingival index at 6th months. Conclusions Systemic administration of moxifloxacin as an adjunct to non-surgical treatment significantly improves clinical outcomes and provides comparable clinical improvement with less adverse events to that of combination of amoxicillin and metronidazole in the treatment of GAgP. Key words: Aggressive periodontitis, amoxicillin, metronidazole, moxifloxacin, nonsurgical periodontal debridement. PMID:26034931

  14. Generalized Aggressive Periodontitis and Its Treatment Options: Case Reports and Review of the Literature

    PubMed Central

    Roshna, T.; Nandakumar, K.

    2012-01-01

    Generalized aggressive periodontitis results in rapid destruction of the periodontium and can lead to early tooth loss in the affected individuals if not diagnosed early and treated appropriately. The diagnostic features of the disease are characteristic, but the clinical presentation and patterns of destructions may vary between patients. Successful management of the disease is challenging especially if diagnosed at advanced stages of the disease, but not impossible with the current therapeutic choices for the disease. A vast array of treatment modalities is available which can be employed in the treatment of generalized aggressive periodontitis with varying success rates, but a definite guideline for the management is yet to be formulated. However, with the exponential rate of developments in periodontal research, regenerative therapy, tissue engineering, and genetic technologies, the future seems promising in regard to options at managing the disease. This paper attempts to describe the clinical and radiographic diagnostic features and the current treatment options along with a suggested protocol for comprehensive management of generalized aggressive periodontitis patients with case reports and a brief review. PMID:22291715

  15. Are herpes virus associated to aggressive periodontitis? A review of literature

    PubMed Central

    Rodrigues, Patrícia Maria de Sousa; Teixeira, Ana Luísa; Kustner, Eduardo Chimenos; Medeiros, Rui

    2015-01-01

    Periodontal Disease includes a wide variety of infectious entities with various clinical manifestations in the oral cavity and responses to treatment. The determinants of clinical manifestations of periodontal disease include the type of infectious agent, the host immune response and environmental factors. Aggressive periodontitis (AP) is defined as a type of inflammation with specific clinical and laboratory features, which distinguish it from other types of periodontitis, with high incidence rates in a sub-group of individuals. Bacteria have been frequently mentioned as the agent inciting gingival inflammation and tissue destruction that underlies the pathogenesis of periodontitis. However, recent studies, with some controversial results, have suggested that the herpes family of viruses, including CMV and EBV-1 as well as papillomaviruses, HIV, Human T-lymphotropic virus type 1, Torquetenovirus and hepatitis B and C occur with high frequency in active periodontal lesions. There is a lack of information about this disease and the role of herpesviruses in its pathophysiology. This review provides a critical analysis of the scientific evidence linking bacteria and viruses with AP and their potential impact on clinical characteristics, prognosis and therapy. PMID:26980964

  16. Nonsyndromic localized aggressive periodontitis of primary dentition: A rare case report

    PubMed Central

    Muppa, Radhika; Nallanchakrava, Srinivas; Chinta, Mahesh; Manthena, Ravi Teja

    2016-01-01

    Periodontitis is an inflammatory disease of the gingiva and tissues of the periodontium. It is characterized by pocket formation and destruction of supporting alveolar bone. Periodontal diseases of aggressive nature are not very common in children. They are usually associated with systemic conditions. The present case report is of a 5-year-old male child who reported with rapid attachment loss and bony defects of the gingiva and supporting structures. His family and medical history gave no contribution for the diagnosis. Blood investigations did not reveal any abnormality. The microbial examination of culture revealed the presence of periodontal pathogen Aggregatibacter actinomycetemcomitans. The treatment objective in the present case was to prevent the further progress of the condition, restore esthetic and function in the child which would psychologically benefit the child. PMID:27307682

  17. Investigation of dental pulp stem cells isolated from discarded human teeth extracted due to aggressive periodontitis.

    PubMed

    Sun, Hai-Hua; Chen, Bo; Zhu, Qing-Lin; Kong, Hui; Li, Qi-Hong; Gao, Li-Na; Xiao, Min; Chen, Fa-Ming; Yu, Qing

    2014-11-01

    Recently, human dental pulp stem cells (DPSCs) isolated from inflamed dental pulp tissue have been demonstrated to retain some of their pluripotency and regenerative potential. However, the effects of periodontal inflammation due to periodontitis and its progression on the properties of DPSCs within periodontally compromised teeth remain unknown. In this study, DPSCs were isolated from discarded human teeth that were extracted due to aggressive periodontitis (AgP) and divided into three experimental groups (Groups A, B and C) based on the degree of inflammation-induced bone resorption approaching the apex of the tooth root before tooth extraction. DPSCs derived from impacted or non-functional third molars of matched patients were used as a control. Mesenchymal stem cell (MSC)-like characteristics, including colony-forming ability, proliferation, cell cycle, cell surface antigens, multi-lineage differentiation capability and in vivo tissue regeneration potential, were all evaluated in a patient-matched comparison. It was found that STRO-1- and CD146-positive DPSCs can be isolated from human teeth, even in very severe cases of AgP. Periodontal inflammation and its progression had an obvious impact on the characteristics of DPSCs isolated from periodontally affected teeth. Although all the isolated DPSCs in Groups A, B and C showed decreased colony-forming ability and proliferation rate (P < 0.05), the decreases were not consistent with the degree of periodontitis. Furthermore, the cells did not necessarily show significantly diminished in vitro multi-differentiation potential. Only DPSCs from Group A and the Control group formed dentin-like matrix in vivo when cell-seeded biomaterials were transplanted directly into an ectopic transplantation model. However, when cell-seeded scaffolds were placed in the root fragments of human teeth, all the cells formed significant dentin- and pulp-like tissues. The ability of DPSCs to generate dental tissues decreased when the

  18. Generalized aggressive periodontitis: microbiological composition and clinical parameters in non-surgical therapy.

    PubMed

    Usin, María M; Tabares, Sandra M; Menso, Julieta; de Albera, Estela R; Sembaj, Adela

    2016-12-01

    The aim of this study was to determine the variations in periodontal parameters and microbiological composition in periodontal pockets at the baseline and 3 and 6 months post treatmentin patients with Generalized Aggressive Periodontitis(GAP) undergoing non surgical periodontal treatment combined with chlorhexidine and systemic antibiotics. Medical and dental history was taken from 10 subjects, average age 30.6±2.7 years, diagnosed with GAP. A non surgical periodontal treatment combined with 0.12% chlorhexidine, 875 mg amoxicillin and 500 mg metronidazole every 12 hours for ten days was conducted. At each visit, the following measurements wererecorded: bacterial plaque (BP), bleeding on probing (BOP), probing depth (PD), clinical attachment level (CAL), hypermobility, and furcation lesions, and a sample of subgingivalplaque was taken from the site of the deepest probing depth of each sextant to identify Porphyromonas gingivalis, Treponemadenticola, Tannerella forsythia, Prevotella intermedia and Aggregatibacter actinomycetemcomitans using molecular biology techniques. After 6 months, the Wilcoxon test showed an increase of 0.97 mm in CAL (p=0.0047) and 2.54 mm in PD(p=0.009). A healthy site was defined as having a PD <5 mm, negative BOP and no pathogenic bacteria detected at 6 months, indicating significant improvement (p=0.008), with OR (95%CI) =4.7 (1.102220.11).With the treatment protocol used in this study, 6 months after treatment, patients had an approximately 4- fold higher possibility of presenting PD <5 mm and periodontal pockets without periodontal pathogenic bacteria.

  19. Revelation of Viral – Bacterial Interrelationship in Aggressive Periodontitis via Polymerase Chain Reaction: A Microbiological Study

    PubMed Central

    Sharma, Sumit; Tapashetti, Roopali P; Patil, Sudhir R; Kalra, Sonali Medsinge; Bhat, Geetha K; Guvva, Sowjanya

    2015-01-01

    Background: Periodontal disease is one of the most common and complex disease affecting mankind. Being multifactorial in etiology it encompasses a variety of infectious entities with various unique microbial constellations and immune responses. A bacteriologic cause alone seems insufficient in explaining several clinical features of the periodontal disease. Recent studies suggest that periodontal herpes viruses comprise an important source of triggering periodontal tissue destruction. The following study aims to assess human cytomegalovirus (HCMV), Epstein-Barr virus (EBV-I) interaction with the established periodontopathic bacteriae, Porphyromonas gingivalis (Pg) and Aggregatibacter actinomycetemcomitans (Aa) in pathogenesis of aggressive periodontitis (AgP) using Hotstart polymerase chain reaction (PCR). Materials and Methods: A total of 30 subjects, 15 with AgP and 15 healthy controls contributed random subgingival plaque samples. PCR methodology was used to identify the subgingival herpesviruses, Pg, and Aa. Yates corrected Chi-square test was employed to identify a statistical association between herpesviruses and periodontopathic bacteriae. Results: Findings suggested that viruses may be pertinent to disease progression. The prevalence of the periodontopathic bacteria Aa was found in 53.33% (P = 0.0168, S) and Pg in 40% (P = 0.2155, NS) of the AgP patients. Herpesviruses, HCMV and EBV-I were found to have a prevalence of 46.67% (P = 0.039, S) and 40% (P = 0.084, NS). The viral and bacterial co-infection was found to be 77.78% (P = 0.0002, S) with Aa and HCMV. Conclusion: The present data reveals, viruses may exert periodontopathic effect by causing local immunosupression which may set a stage for the subgingival colonization and multiplication of periodontal bacteriae. Further studies are needed to develop an understanding into the significance of herpesviruses in human periodontitis which, may allow for improved diagnosis, more specific therapy and

  20. Photodynamic therapy in the treatment of aggressive periodontitis: A systematic review

    PubMed Central

    Doufexi, Aikaterini-Ellisavet

    2016-01-01

    Background Aggressive periodontitis (AgP) is a severe form of periodontal diseases with rapid destruction of the supporting bone around teeth. The efficacy of PDT in suppressing periodontal pathogens may be crucial in adopting new protocols for the treatment of AgP. Thus, the aim of this systematic review was to investigate the possible role of PDT in the treatment of AgP as an adjunctive therapy or monotherapy. Material and Methods A systematic search of the literature was performed. Additionally, the references from all the selected full-text studies were searched for relevant articles. Two reviewers screened independently titles and abstracts or full text copies. Quality assessment of all the included studies was held. Results Initial screening of electronic databases yielded 418 potentially relevant publications. After screening of the titles and full-text examination, five studies were included in the systematic review. Four publications evaluated the effects of PDT adjunctive to SRP in patients with AgP: two of them compared the clinical outcomes of SRP and PDT with a control group that received therapy with SRP and antibiotics (metronidazole and amoxicillin); two publications included SRP and PDT in the test group, and SRP alone in the control group. In one study, PDT was tested as a monotherapy compared with SRP alone. Conclusions Within the limitations of this review, PDT may exhibit a beneficial role in the therapy of aggressive periodontitis after repeated applications. In the future, more methodologically sound, long-term randomized clinical trials are needed to be conducted. Key words:Photodynamic therapy, periodontitis, systematic review. PMID:26595837

  1. Effect of Surgical Periodontal Therapy on Serum C-reactive Protein Levels Using ELISA in Both Chronic and Aggressive Periodontitis Patient

    PubMed Central

    Gupta, Bharat; Patil, Neha; Yadav, Manoj; Tripathi, Shashank; Sinha, Saurabh; Sharma, Saurabh; Gupta, Saurabh

    2015-01-01

    Background Periodontitis can be defined as a local inflammatory process which mediates destruction of periodontal tissues & is triggered by bacterial insult. In periodontal infections, the levels of C reactive proteins are elevated as compared to the levels in a periodontally healthy individual. The study was done to determine the relative levels of serum CRP in aggressive, chronic and periodontally healthy subjects and to evaluate the effect of surgical periodontal therapy on serum C-reactive protein levels. Materials and Methods Serum samples were collected from 150 participants (50 healthy control patients (non-periodontitis), 50 patients with chronic periodontitis and aggressive periodontitis. Serum C- reactive protein levels were assessed by means of immunoturbidimetric assay at baseline for subjects in all the 3 groups and 3 months after completion of surgical therapy. Results The mean baseline C-reactive protein (CRP) concentrations in the Groups I, II and III were 1.65±0.57 mg/L, 3.03±2.14 mg/L and 3.09±2.27 mg/L respectively. After treatment, the mean C-reactive protein (CRP) levels in Groups II and III reduced from 3.03±1.67 mg/L to 1.46±1.67 mg/L and from 3.09±1.21 to 1.43±1.21 mg/L respectively. Similar results were found for probing depth and all indexes in Group II and III after treatment. Also, the mean attachment loss in Groups II and III reduced, so the results were highly significant. Conclusion Successful periodontal treatment results in significant decrease in serum C-reactive protein (CRP) levels in otherwise healthy subjects. PMID:26557605

  2. Lack of association between the TNF-α-1031genotypes and generalized aggressive periodontitis disease.

    PubMed

    Darvishi, E; Aziziaram, Z; Yari, K; Bagheri Dehbaghi, M; Kahrizi, D; Karim, H; Vaziri, S; Zargooshi, J; Ghadiri, K; Muhammadi, S; Kazemi, E; Moradi, M T; Shokrinia, M; Mohammadi, N

    2016-09-30

    Periodontal disease is one of the most prevalent inflammatory illnesses and is a main cause of tooth loss in human population. Tumor necrosis factor-α (TNF-α) gene is one of pro-inflammatory cytokines which has important role in pathogenesis of periodontal disease. The main purpose of this study is to determine genotype abundance of TNF-α-1031 gene in both groups of patients and controls, and also investigation of relation of single nucleotide polymorphism (SNP) these genotypes with periodontal disease risk. DNA was extracted from blood tissue of 31 patients and 54 controls. The TNF-α-1031 polymorphism was evaluated by polymerase chain reaction- confronting two-pair primer (PCR-CTPP) method. In the GAP group, the frequencies of TT, TC and CC genotypes were 35.48%, 61.29 and 3.23%, respectively. In controls the frequencies of TT, TC and CC genotypes were 22.22%, 72.22%, and 5.56%, respectively. Results of this study showed that there was no significant association between TNF-α (-1031 T/C promoter) gene polymorphisms and the risk of generalized aggressive periodontitis disease.

  3. Aggregatibacter actinomycetemcomitans: virulence of its leukotoxin and association with aggressive periodontitis.

    PubMed

    Åberg, Carola Höglund; Kelk, Peyman; Johansson, Anders

    2015-01-01

    Periodontitis is an infection-induced inflammatory disease that causes loss of the tooth supporting tissues. Much focus has been put on comparison of the microbial biofilm in the healthy periodontium with the diseased one. The information arising from such studies is limited due to difficulties to compare the microbial composition in these two completely different ecological niches. A few longitudinal studies have contributed with information that makes it possible to predict which individuals who might have an increased risk of developing aggressive forms of periodontitis, and the predictors are either microbial or/and host-derived factors. The most conspicuous condition that is associated with disease risk is the presence of Aggregatibacter actinomycetemcomitans at the individual level. This Gram-negative bacterium has a great genetic variation with a number of virulence factors. In this review we focus in particular on the leukotoxin that, based on resent knowledge, might be one of the most important virulence factors of A. actinomycetemcomitans.

  4. Pathogenicity of the highly leukotoxic JP2 clone of Aggregatibacter actinomycetemcomitans and its geographic dissemination and role in aggressive periodontitis

    PubMed Central

    Haubek, Dorte; Johansson, Anders

    2014-01-01

    For decades, Aggregatibacter actinomycetemcomitans has been associated with aggressive forms of periodontitis in adolescents. In the middle of the 1990s, a specific JP2 clone of A. actinomycetemcomitans, belonging to the cluster of serotype b strains of A. actinomycetemcomitans and having a number of other characteristics, was found to be strongly associated with aggressive forms of periodontitis, particularly in North Africa. Although several longitudinal studies still point to the bacterial species, A. actinomycetemcomitans as a risk factor of aggressive periodontitis, it is now also widely accepted that the highly leukotoxic JP2 clone of A. actinomycetemcomitans is implicated in rapidly progressing forms of aggressive periodontitis. The JP2 clone strains are highly prevalent in human populations living in Northern and Western parts of Africa. These strains are also prevalent in geographically widespread populations that have originated from the Northwest Africa. Only sporadic signs of a dissemination of the JP2 clone strains to non-African populations have been found despite Africans living geographically widespread for hundreds of years. It remains an unanswered question if a particular host tropism exists as a possible explanation for the frequent colonization of the Northwest African population with the JP2 clone. Two exotoxins of A. actinomycetemcomitans are known, leukotoxin (LtxA) and cytolethal distending toxin (Cdt). LtxA is able to kill human immune cells, and Cdt can block cell cycle progression in eukaryotic cells and thus induce cell cycle arrest. Whereas the leukotoxin production is enhanced in JP2 clone strains thus increasing the virulence potential of A. actinomycetemcomitans, it has not been possible so far to demonstrate such a role for Cdt. Lines of evidence have led to the understanding of the highly leukotoxic JP2 clone of A. actinomycetemcomitans as an aetiological factor of aggressive periodontitis. Patients, who are colonized with the JP2

  5. Pathogenicity of the highly leukotoxic JP2 clone of Aggregatibacter actinomycetemcomitans and its geographic dissemination and role in aggressive periodontitis.

    PubMed

    Haubek, Dorte; Johansson, Anders

    2014-01-01

    For decades, Aggregatibacter actinomycetemcomitans has been associated with aggressive forms of periodontitis in adolescents. In the middle of the 1990s, a specific JP2 clone of A. actinomycetemcomitans, belonging to the cluster of serotype b strains of A. actinomycetemcomitans and having a number of other characteristics, was found to be strongly associated with aggressive forms of periodontitis, particularly in North Africa. Although several longitudinal studies still point to the bacterial species, A. actinomycetemcomitans as a risk factor of aggressive periodontitis, it is now also widely accepted that the highly leukotoxic JP2 clone of A. actinomycetemcomitans is implicated in rapidly progressing forms of aggressive periodontitis. The JP2 clone strains are highly prevalent in human populations living in Northern and Western parts of Africa. These strains are also prevalent in geographically widespread populations that have originated from the Northwest Africa. Only sporadic signs of a dissemination of the JP2 clone strains to non-African populations have been found despite Africans living geographically widespread for hundreds of years. It remains an unanswered question if a particular host tropism exists as a possible explanation for the frequent colonization of the Northwest African population with the JP2 clone. Two exotoxins of A. actinomycetemcomitans are known, leukotoxin (LtxA) and cytolethal distending toxin (Cdt). LtxA is able to kill human immune cells, and Cdt can block cell cycle progression in eukaryotic cells and thus induce cell cycle arrest. Whereas the leukotoxin production is enhanced in JP2 clone strains thus increasing the virulence potential of A. actinomycetemcomitans, it has not been possible so far to demonstrate such a role for Cdt. Lines of evidence have led to the understanding of the highly leukotoxic JP2 clone of A. actinomycetemcomitans as an aetiological factor of aggressive periodontitis. Patients, who are colonized with the JP2

  6. GC Gene Polymorphisms and Vitamin D-Binding Protein Levels Are Related to the Risk of Generalized Aggressive Periodontitis

    PubMed Central

    Song, Wenli; Wang, Xian'e; Tian, Yu; Zhang, Xin; Lu, Ruifang

    2016-01-01

    Objective. To explore whether GC (group-specific component) rs17467825, rs4588, and rs7041 polymorphisms are associated with generalized aggressive periodontitis. Methods. This case-control study recruited 372 patients with generalized aggressive periodontitis (group AgP) and 133 periodontal healthy subjects (group HP). GC rs17467825, rs4588, and rs7041 genotypes and plasmatic vitamin D-binding protein (DBP) were measured. Analysis of single SNP and multiple SNPs was performed and relevance between plasmatic DBP and haplotypes was analyzed. Results. GC rs17467825 GG genotype was statistically associated with lower risk for generalized aggressive periodontitis under the recessive model (OR = 0.52, 95% CI: 0.30–0.92, p = 0.028). GC rs17467825 and rs4588 had strong linkage disequilibrium with r2 ≥ 0.8 and D′ ≥ 0.8. Haplotype (GC rs17467825, rs4588) GC was associated with the less risk for generalized aggressive periodontitis (OR = 0.29, 95% CI: 0.09–0.96, p = 0.043). In group AgP, individuals with combined genotype (GC rs17467825, rs4588) AG+CA had significantly lower plasmatic DBP level than those with the other two combined genotypes (AG+CA versus AA+CC p = 0.007; AG+CA versus GG+AA p = 0.026). Conclusions. GC rs17467825 genotype GG and haplotype (GC rs17467825, rs4588) GC are associated with generalized aggressive periodontitis. The association may be acquired through regulating DBP levels. The functions of GC gene and DBP in inflammatory disease need to be further studied. PMID:28018430

  7. Artificial Neural Networks for the Diagnosis of Aggressive Periodontitis Trained by Immunologic Parameters

    PubMed Central

    Papantonopoulos, Georgios; Takahashi, Keiso; Bountis, Tasos; Loos, Bruno G.

    2014-01-01

    There is neither a single clinical, microbiological, histopathological or genetic test, nor combinations of them, to discriminate aggressive periodontitis (AgP) from chronic periodontitis (CP) patients. We aimed to estimate probability density functions of clinical and immunologic datasets derived from periodontitis patients and construct artificial neural networks (ANNs) to correctly classify patients into AgP or CP class. The fit of probability distributions on the datasets was tested by the Akaike information criterion (AIC). ANNs were trained by cross entropy (CE) values estimated between probabilities of showing certain levels of immunologic parameters and a reference mode probability proposed by kernel density estimation (KDE). The weight decay regularization parameter of the ANNs was determined by 10-fold cross-validation. Possible evidence for 2 clusters of patients on cross-sectional and longitudinal bone loss measurements were revealed by KDE. Two to 7 clusters were shown on datasets of CD4/CD8 ratio, CD3, monocyte, eosinophil, neutrophil and lymphocyte counts, IL-1, IL-2, IL-4, INF-γ and TNF-α level from monocytes, antibody levels against A. actinomycetemcomitans (A.a.) and P.gingivalis (P.g.). ANNs gave 90%–98% accuracy in classifying patients into either AgP or CP. The best overall prediction was given by an ANN with CE of monocyte, eosinophil, neutrophil counts and CD4/CD8 ratio as inputs. ANNs can be powerful in classifying periodontitis patients into AgP or CP, when fed by CE values based on KDE. Therefore ANNs can be employed for accurate diagnosis of AgP or CP by using relatively simple and conveniently obtained parameters, like leukocyte counts in peripheral blood. This will allow clinicians to better adapt specific treatment protocols for their AgP and CP patients. PMID:24603408

  8. Comparison of various risk indicators among patients with chronic and aggressive periodontitis in davangere population

    PubMed Central

    Vandana, Kharidhi Laxman; Nadkarni, Rahul Dilip; Guddada, Kaveri

    2015-01-01

    Background: The aim of the present study was to compare various risk indicators of chronic periodontitis (CP) and aggressive periodontitis (AP) among patients of Davangere population. Materials and Methods: Totally, 89 CP and 90 AP patients were selected from outpatient Department of Periodontics, College of Dental Sciences, Davangere. Various clinical parameters proven to be risk indicators were determined for each patient such as age, gender, occupation, oral hygiene habits, personal habits, income, level of education, place of residence, frequency of dental visits, various oral hygiene indices, gingival status, wasting diseases, malocclusion, laboratory investigations, and the results were subjected to statistical analysis. Results: This study demonstrated that AP is manifested early in life in susceptible individuals. Proven risk indicators for AP and CP in the present study population included young age, place of residence, income and education levels, frequency of dental visits. Patients with AP had better oral hygiene habits and oral hygiene index results than patients with CP. Paan chewing and smoking could be considered as risk factors, both in CP and AP cases. The similar association of plaque scores but higher bleeding tendency in AP patients supported the fact of higher susceptibility of AP patients to periodontal breakdown. Malocclusion being present in the majority of cases could also be put forth as a risk factor for AP and CP. Conclusion: This study identifies the different risk indicators for CP and AP and demonstrates the need for constructing nationwide oral health promotion programs to improve the level of oral health awareness and standards in Indian population. PMID:26392693

  9. Association between Manganese Superoxide Dismutase (MnSOD Val-9Ala) genotypes with the risk of generalized aggressive periodontitis disease.

    PubMed

    Kazemi, E; Moradi, M-T; Yari, K; Mousavi, S A R; Kahrizi, D

    2015-12-19

    Generalized aggressive periodontitis (GAP) is a subtype of periodontal diseases that characterized by rapid destruction of periodontal supporting tissues. The MnSOD Val-9Ala mutation of manganese superoxide dismutase gene (MnSOD Val-9Ala) and its correlation with periodontal diseases has been studied in different populations. The purpose of this study was to investigate the possible association of MnSODVal-9Ala polymorphism with periodontitis disease in sample of GAP patients in Iran for the first time. Following a GAP examination, 50 GAP patients and 100 healthy individuals were recruited. Genomic DNA was extracted from peripheral blood leukocytes and the MnSODVal-9Ala polymorphismwas detected using PCR-RFLP method. The frequency of Ala/Ala, Ala/Val and Val/Val genotypes in healthy individuals were 25, 66 and 9%, respectively. In periodontitis patients, frequencies were as Ala/Ala (12%), Ala/Val (50%) and Val/Val (38%) genotypes. There was a significant positive association between distribution of MnSOD Val-9Ala genotypes and the risk of periodontitis disease (p<0.05). Our results indicated that MnSOD Val-9Ala gene polymorphism has a positive association with the risk of periodontitis disease.

  10. Abernathy's Lap

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A lap in this instance is not a midriff but a tool for presision.polishing and grinding. During the Saturn V moonbooster program, Marshall Space Flight Center found a need for a better lap. The need arose from the exquisitely precise tolerances required for parts of the launch vehicle's guidance,and control system. So William J. Abernathy, a former Marshall employee, built a better lap; he invented a method for charging aluminum lap plates with diamond powder, then hard-anodizing them. The resulting lap produces a high polish on materials ranging from the softest aluminum to the hardest ceramics. It operates faster, wears longer and requires less reworking. Abernathy got NASA's permission to obtain a personal patent and he formed the one-man Abernathy Laps Co. in Huntsville, which produces a variety of laps. One of Abernathy's customers is Bell Aerospace Textron, Buffalo, which uses the laps to finish polish delicate instrument parts produced for NASA's Viking and other space programs. Says a Bell official: "Time needed (with the Abernathy lap) is a fraction of that required by conventional methods. The result is extremely accurate flatness and surface finish." Abernathy is providing laps for other manufacturing applications and for preparation of metallurgical specimens. The business is small but steady, and Abernathy plans expansion into other markets.

  11. Periodontitis

    MedlinePlus

    ... This is called gingivitis, the mildest form of periodontal disease. Ongoing inflammation eventually causes pockets to develop between ... you to a specialist in the treatment of periodontal disease (periodontist). Diagnosis of periodontitis is generally simple. Diagnosis ...

  12. Prevalence of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythia in Japanese patients with generalized chronic and aggressive periodontitis.

    PubMed

    Tomita, Sachiyo; Komiya-Ito, Akiyo; Imamura, Kentaro; Kita, Daichi; Ota, Koki; Takayama, Saori; Makino-Oi, Asako; Kinumatsu, Takashi; Ota, Mikio; Saito, Atsushi

    2013-01-01

    This study aimed to investigate the prevalence and levels of major periodontal pathogens, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythia in subgingival plaque samples of a group of Japanese patients with aggressive periodontitis (AgP) and chronic periodontitis (CP). A total of 40 patients with clinical diagnosis of AgP or CP and 10 periodontally healthy volunteers were subjected to clinical and microbiological analysis. Subgingival plaque samples were analyzed for A. actinomycetemcomitans, P. gingivalis and T. forsythia with a real-time polymerase chain reaction (PCR) technique. The prevalence of P. gingivalis and T. forsythia was relatively high in patients with periodontitis: over 60% of AgP or CP patients harbored these pathogens whereas they were not detected in the subgingival plaque samples from periodontally healthy individuals. P. gingivalis and T. forsythia were relatively frequently detected together in AgP and CP patients. No significant differences in the prevalence or level of the 3 pathogens were found between periodontitis groups. The proportion of T. forsythia was approximately 4-fold higher in CP group than in AgP group (P = 0.02). In periodontitis patients, a significant positive correlation was found between periodontal parameters (probing depth and clinical attachment level) and the numbers of total bacteria, P. gingivalis and T. forsythia. No distinct pattern of the subgingival profile of these pathogens was discerned between the two disease entities, except for the difference in the proportion of T. forsythia. The red complex bacteria, P. gingivalis and T. forsythia were highly prevalent in this population of Japanese AgP and CP patients, collaborating their roles in periodontitis.

  13. 16S rRNA based microarray analysis of ten periodontal bacteria in patients with different forms of periodontitis.

    PubMed

    Topcuoglu, Nursen; Kulekci, Guven

    2015-10-01

    DNA microarray analysis is a computer based technology, that a reverse capture, which targets 10 periodontal bacteria (ParoCheck) is available for rapid semi-quantitative determination. The aim of this three-year retrospective study was to display the microarray analysis results for the subgingival biofilm samples taken from patient cases diagnosed with different forms of periodontitis. A total of 84 patients with generalized aggressive periodontitis (GAP,n:29), generalized chronic periodontitis (GCP, n:25), peri-implantitis (PI,n:14), localized aggressive periodontitis (LAP,n:8) and refractory chronic periodontitis (RP,n:8) were consecutively selected from the archives of the Oral Microbiological Diagnostic Laboratory. The subgingival biofilm samples were analyzed by the microarray-based identification of 10 selected species. All the tested species were detected in the samples. The red complex bacteria were the most prevalent with very high levels in all groups. Fusobacterium nucleatum was detected in all samples at high levels. The green and blue complex bacteria were less prevalent compared with red and orange complex, except Aggregatibacter actinomycetemcomitas was detected in all LAP group. Positive correlations were found within all the red complex bacteria and between red and orange complex bacteria especially in GCP and GAP groups. Parocheck enables to monitoring of periodontal pathogens in all forms of periodontal disease and can be alternative to other guiding and reliable microbiologic tests.

  14. Detection of Porphyromonas gingivalis and Treponema denticola in chronic and aggressive periodontitis patients: A comparative polymerase chain reaction study

    PubMed Central

    Kumawat, Ramniwas M.; Ganvir, Sindhu M.; Hazarey, Vinay K.; Qureshi, Asifa; Purohit, Hemant J.

    2016-01-01

    Background: The detection frequency of Porphyromonas gingivalis and Treponema denticola in chronic periodontitis (CP) and aggressive periodontitis (AgP) is not explored well in Indian population. Aim: The study was undertaken to detect P. gingivalis and T. denticola in CP as well as in AgP patients using polymerase chain reaction (PCR), and to determine the relationship between the frequency of these two microorganisms and the severity of clinical periodontal parameters. Materials and Methods: Subgingival plaque samples were collected from ninety participants (thirty CP patients, thirty AgP patients, and thirty healthy participants) and the aforementioned two microorganisms were detected using PCR. Results: However, when CP and AgP were compared for the detection frequency of two microorganisms, no statistically significant difference was noted. A statistically significant increase in the number of bacteria-positive sites increased as the score of plaque index (PI), gingival index (GI), and clinical attachment level of CP and AgP patients increased. Coexistence of P. gingivalis and T. denticola was frequently observed in deep periodontal pockets. Conclusions: Study findings suggest that P. gingivalis and T. denticola are significantly associated with the severity of periodontal tissue destruction. Statistically significant association exists between clinical periodontal parameters such as PI, GI, periodontal pocket depth (PPD), and clinical attachment loss and presence of both the microorganisms. PMID:27994415

  15. Use of Emdogain enamel matrix proteins in the surgical treatment of aggressive periodontitis.

    PubMed

    Kiernicka, Małgorzata; Owczarek, Barbara; Gałkowska, Ewa; Wysokińska-Miszczuk, Joanna

    2003-01-01

    One of the ways of treating of the aggressive forms of periodontitis is the method of guided tissue regeneration using enamel matrix proteins included in Emdogain preparation. The aim of work was clinical evaluation of the complex treatment of those periodontolyses using the above mentioned material as the implant material. 35 intrabony pockets were operated in 11 patients aged 17-50. The treatment results were described with the use of clinical indices of API and SBI, indices of pockets depth PPD and the loss of the attachment CAL indices before and within the period of 8 to 12 months after the surgeries. The values of the examined features were submitted to statistical analysis using Shapiro-Wilks and Wilcoxon's tests. The treatment that was applied led to extremely statistically significant improvement of the examined parameters.

  16. Aggregatibacter actinomycetemcomitans: Virulence of its leukotoxin and association with aggressive periodontitis

    PubMed Central

    Åberg, Carola Höglund; Kelk, Peyman; Johansson, Anders

    2015-01-01

    Periodontitis is an infection-induced inflammatory disease that causes loss of the tooth supporting tissues. Much focus has been put on comparison of the microbial biofilm in the healthy periodontium with the diseased one. The information arising from such studies is limited due to difficulties to compare the microbial composition in these two completely different ecological niches. A few longitudinal studies have contributed with information that makes it possible to predict which individuals who might have an increased risk of developing aggressive forms of periodontitis, and the predictors are either microbial or/and host-derived factors. The most conspicuous condition that is associated with disease risk is the presence of Aggregatibacter actinomycetemcomitans at the individual level. This Gram-negative bacterium has a great genetic variation with a number of virulence factors. In this review we focus in particular on the leukotoxin that, based on resent knowledge, might be one of the most important virulence factors of A. actinomycetemcomitans. PMID:25494963

  17. The microbial community shifts of subgingival plaque in patients with generalized aggressive periodontitis following non-surgical periodontal therapy: a pilot study.

    PubMed

    Han, Jing; Wang, Peng; Ge, Shaohua

    2017-02-07

    The object of this study is to characterize the bacterial community of subgingival plaque of two subjects with generalized aggressive periodontitis (GAgP) pre- and post-treatment. We picked two patients with GAgP and used high-throughput 16S rDNA sequencing. V4 hypervariable region was picked for PCR amplification of subgingival samples. Then, the PCR products were sequenced through Illumina MiSeq platform. One month after therapy, both the clinical features and periodontal parameters improved obviously. Moreover, the composition and structure of subgingival bacterial community changed after initial periodontal therapy. Also, the composition of the subgingival microbiota was highly individualized among different patients. Bacteroidetes, Spirochaetes and Fusobacteria were related to pathogenicity of GAgP while Actinobacteria and Proteobacteria seemed associated with clinical symptoms resolution. In this study, we found the subgingival bacterial community was high in species richness but dominated by a few species or phylotypes, with significant shifts of microbiota that occurred after treatment. This study demonstrated the shift of the subgingival bacterial community before and after treatment by high-throughput 16S rDNA sequencing, and provided a concise method for analysis of microbial community for periodontal diseases.

  18. A Putative Association of a Single Nucleotide Polymorphism in GPR126 with Aggressive Periodontitis in a Japanese Population

    PubMed Central

    Asano, Yoshihiro; Imai, Atsuko; Kawai, Shinji; Michikami, Ikumi; Yamashita, Motozo; Yamada, Satoru; Kitamura, Masahiro; Murakami, Shinya

    2016-01-01

    Periodontitis is an inflammatory disease causing loss of tooth-supporting periodontal tissue. Disease susceptibility to the rapidly progressive form of periodontitis, aggressive periodontitis (AgP), appears to be influenced by genetic risk factors. To identify these in a Japanese population, we performed whole exome sequencing of 41 unrelated generalized or localized AgP patients. We found that AgP is putatively associated with single nucleotide polymorphism (SNP) rs536714306 in the G-protein coupled receptor 126 gene, GPR126 [c.3086 G>A (p.Arg1029Gln)]. Since GPR126 activates the cAMP/PKA signaling pathway, we performed cAMP ELISA analysis of cAMP concentrations, and found that rs536714306 impaired the signal transactivation of GPR126. Moreover, transfection of human periodontal ligament (HPDL) cells with wild-type or mutant GPR126 containing rs536714306 showed that wild-type GPR126 significantly increased the mRNA expression of bone sialoprotein, osteopontin, and Runx2 genes, while mutant GPR126 had no effect on the expression of these calcification-related genes. The increase in expression of these genes was through the GPR126-induced increase of bone morphogenic protein-2, inhibitor of DNA binding (ID) 2, and ID4 expression. These data indicate that GPR126 might be important in maintaining the homeostasis of periodontal ligament tissues through regulating the cytodifferentiation of HPDL cells. The GPR126 SNP rs536714306 negatively influences this homeostasis, leading to the development of AgP, suggesting that it is a candidate genetic risk factor for AgP in the Japanese population. PMID:27509131

  19. A combined regenerative approach for the treatment of aggressive periodontitis: long-term follow-up of a familial case.

    PubMed

    Sant'Ana, Adriana Campos Passanezi; Passanezi, Euloir; Todescan, Sylvia Maria Correia; de Rezende, Maria Lúcia Rubo; Greghi, Sebastião Luiz Aguiar; Ribeiro, Mônica Garcia

    2009-02-01

    This article reports the longitudinal follow-up of a familial case of aggressive periodontitis treated by a combined regenerative approach that consisted of root conditioning, bone grafting, and membrane positioning. Treatment resulted in attachment level gain, reduction of probing depth, absence of bleeding on probing, and complete bone filling of the defect. The short-term results obtained after surgery were maintained after 6 years, suggesting that the combined regenerative approach is able to completely arrest the disease with long-term stability.

  20. Periodontitis

    MedlinePlus

    ... your dentist if you have signs of gum disease. Prevention Good oral hygiene is the best way to prevent periodontitis. This includes thorough tooth brushing and flossing, and regular professional dental cleaning. Preventing and treating ... References Amsterdam JT. ...

  1. Treatment of intrabony defects with anorganic bone matrix/p-15 or guided tissue regeneration in patients with aggressive periodontitis.

    PubMed

    Queiroz, Adriana C; Nóbrega, Priscila Brasil da; Oliveira, Fabíola S; Novaes, Arthur B; Taba, Mário; Palioto, Daniela B; Grisi, Márcio F M; Souza, Sergio L S

    2013-01-01

    Intrabony periodontal defects present a particular treatment problem, especially in patients with generalized aggressive periodontitis (G-AgP). Regenerative procedures have been indicated for this clinical situation. The aim of this study was to compare treatment outcomes of intrabony periodontal defects with either anorganic bone matrix/cell binding peptide (ABM/P-15) or guided tissue regeneration (GTR) in patients with G-AgP. Fifteen patients, with two intrabony defects ≥3 mm deep, were selected. Patients were randomly allocated to be treated with ABM/P-15 or GTR. At baseline and at 3 and 6 months after surgery, clinical and radiographic parameters and IL-1β and IL-6 gingival fluid concentrations were recorded. There was a significant probing pocket depth reduction (p<0.001) for both groups (2.27 ± 0.96 mm for ABM/P-15 group and 2.57 ± 1.06 mm for GTR group). Clinical attachment level gain (1.87 ± 0.94 mm for ABM/P-15 group and 2.09 ± 0.88 mm for GTR group) was also observed. There were no statistically significant differences in clinical parameters between the groups. The radiographic bone fill was more expressive in ABM/P-15 group (2.49 mm) than in GTR group (0.73 mm). In subtraction radiographs, the areas representing gain in density were 93.16% of the baseline defect for ABM/P-15 group versus 62.03% in GRT group. There were no statistically significant differences in inter-group and intra-group comparisons with regards to IL-1β and IL-6 quantification. Treatment of intrabony periodontal defects in patients with G-AgP with ABM/P-15 and GTR improved significantly the clinical outcomes. The use of ABM/P-15 promoted a better radiographic bone fill.

  2. Long-term evaluation of the antimicrobial susceptibility and microbial profile of subgingival biofilms in individuals with aggressive periodontitis

    PubMed Central

    Lourenço, Talita Gomes Baêta; Heller, Débora; do Souto, Renata Martins; Silva-Senem, Mayra Xavier e; Varela, Victor Macedo; Torres, Maria Cynesia Barros; Feres-Filho, Eduardo Jorge; Colombo, Ana Paula Vieira

    2015-01-01

    This study evaluates the antimicrobial susceptibility and composition of subgingival biofilms in generalized aggressive periodontitis (GAP) patients treated using mechanical/antimicrobial therapies, including chlorhexidine (CHX), amoxicillin (AMX) and metronidazole (MET). GAP patients allocated to the placebo (C, n = 15) or test group (T, n = 16) received full-mouth disinfection with CHX, scaling and root planning, and systemic AMX (500 mg)/MET (250 mg) or placebos. Subgingival plaque samples were obtained at baseline, 3, 6, 9 and 12 months post-therapy from 3–4 periodontal pockets, and the samples were pooled and cultivated under anaerobic conditions. The minimum inhibitory concentrations (MICs) of AMX, MET and CHX were assessed using the microdilution method. Bacterial species present in the cultivated biofilm were identified by checkerboard DNA-DNA hybridization. At baseline, no differences in the MICs between groups were observed for the 3 antimicrobials. In the T group, significant increases in the MICs of CHX (p < 0.05) and AMX (p < 0.01) were detected during the first 3 months; however, the MIC of MET decreased at 12 months (p < 0.05). For several species, the MICs significantly changed over time in both groups, i.e., Streptococci MICs tended to increase, while for several periodontal pathogens, the MICs diminished. A transitory increase in the MIC of the subgingival biofilm to AMX and CHX was observed in GAP patients treated using enhanced mechanical therapy with topical CHX and systemic AMX/MET. Both protocols presented limited effects on the cultivable subgingival microbiota. PMID:26273264

  3. Increased systemic elastase and C-reactive protein in aggressive periodontitis (CLOI-D-00160R2).

    PubMed

    Wohlfeil, Martin; Scharf, Susanne; Siegelin, Yasemin; Schacher, Beate; Oremek, Gerhard M; Sauer-Eppel, Hildegund; Schubert, Ralf; Eickholz, Peter

    2012-08-01

    The inflammatory mediators, serum elastase and C-reactive protein (CRP), are associated with an increased risk for coronary heart disease. Thus, the aim of this study is to compare systemic inflammatory mediators in periodontally healthy controls (C), patients with untreated aggressive (AgP) and chronic (ChP) periodontitis. C [periodontal pocket probing depth (PPD)  <3.6 or <5 mm without bleeding (BOP), BOP < 10%], ChP (PDD ≥ 3.6 mm and probing attachment loss ≥5 mm at >30% of sites; age >35 years), and AgP (clinically healthy; PDD ≥ 3.6 mm at >30% of sites, bone loss ≥50% at ≥2 teeth; age ≤35 years) were examined clinically, and the body mass index was assessed. Blood was sampled for assessment of serum levels of elastase, CRP, lipopolysaccharide binding protein (LBP), interleukin (IL) 6, 8, and leukocyte counts. Thirty C, 31 ChP, and 29 AgP were analyzed. Elastase, CRP, LBP, and IL-6 levels were elevated in AgP compared to C (p < 0.013), whereas leukocyte counts and IL-8 were similar. Multiple regression analysis identified AgP (p < 0.001) and education level (p < 0.001) to explain 47% of the variation of elastase. AgP (p = 0.003), African origin (p = 0.006), female sex (p = 0.002), and BMI (p < 0.001) explained 39% of the variation of CRP. Serum elastase and CRP are significantly elevated in AgP compared to C. AgP patients exhibit a stronger systemic inflammatory burden than C patients.

  4. Efficacy of Photodynamic Therapy and Lasers as an Adjunct to Scaling and Root Planing in the Treatment of Aggressive Periodontitis – A Clinical and Microbiologic Short Term Study

    PubMed Central

    Sarkar, Indranil; Rajan, Padma; Pai, Jagdish; Malagi, Sachin; Bharmappa, Radhika; Kamath, Vinesh

    2016-01-01

    Introduction Aggressive periodontitis comprises a group of rare, severe, rapidly progressive form of periodontitis. Conventional treatment includes mechanical debridement augmented with adjunctive antimicrobial therapy. Development of antibiotic resistance has led to use of lasers. Photodynamic therapy (PDT) is a novel non-invasive therapeutic approach with increased site and pathogen specificity. This study compares PDT and Lasers as an adjunct to conventional Scaling in the treatment of patients with aggressive periodontitis. Materials and Methods Fifteen untreated aggressive periodo-ntitis patients were randomly assigned in a split mouth design for one of the following treatment modalities: 1) SRP alone; (2) SRP + Diode Laser irradiation with 810 nm at 1W, continuous mode for 30 sec per tooth; (3) SRP + PDT on “0” day; (4) SRP + PDT on “0”, 7th and 21st day. The clinical parameters included PI, BOP, PPD, CAL recorded at the baseline & 3rd month. The site with greatest probing pocket depth (PPD) was selected from each quadrant for bacterial sampling and cultured for Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis & Prevotella intermedia. Results Statistically significant reduction in clinical & microbial parameters was seen. Sites 4 showed a greater reduction compared to other groups. Conclusion Photodynamic therapy is a valuable treatment modality adjunctive to conventional scaling and root planing. PMID:27042576

  5. Clinical and radiographic evaluation of Emdogain as a regenerative material in the treatment of interproximal vertical defects in chronic and aggressive periodontitis patients.

    PubMed

    Vandana, K L; Shah, Kinnari; Prakash, Shobha

    2004-04-01

    This study evaluated the efficacy of Emdogain enamel matrix proteins as a regenerative material in interproximal vertical defects both clinically and radiographically. Patients aged 18 to 45 years and diagnosed with chronic or aggressive periodontitis were included. Sixteen intrabony defects in eight patients were surgically treated using a split-mouth design. Emdogain placement was done at experimental sites. Since both chronic and aggressive periodontitis patients were included, an attempt was made to interpret results between the two types of cases. Postsurgical measurements at 9 months revealed no significant difference in mean pocket depth reduction, clinical attachment level gain, amount of defect fill, or defect resolution between control and experimental groups. Mean pocket depth reduction and amount of defect fill were significant in both groups. The results were interpreted separately for chronic and aggressive periodontitis cases. This study demonstrated no added advantage of using Emdogain compared to surgical debridement alone. Further long-term and large-sample-size evaluation is required to prove Emdogain's consistent efficacy.

  6. How cats lap

    NASA Astrophysics Data System (ADS)

    Stocker, Roman; Reis, Pedro; Jung, Sunghwan; Aristoff, Jeffrey

    2010-11-01

    We studied the lapping of the domestic cat (Felis catus) by combining high-speed photography with a laboratory model of lapping. We found that Felis catus laps by a subtle mechanism based on water adhesion to the dorsal side of the tongue and the creation of a liquid column, exploiting inertia to defeat gravity and pull liquid into the mouth. The competition between inertia and gravity controls the pinch-off time of the column, determining the optimal lapping frequency, f. Felis catus was found to operate near the optimum and theoretical analysis yielded a scaling, f ˜M-1/6, of lapping frequency with animal mass, M. This prediction was verified by measuring lapping frequency across felids, from ocelots to lions, suggesting that the lapping mechanism is conserved among felines.

  7. The Outcome of a Preventive Dental Care Programme on the Prevalence of Localized Aggressive Periodontitis in Down's Syndrome Individuals

    ERIC Educational Resources Information Center

    Zigmond, Maora; Stabholz, A.; Shapira, J.; Bachrach, G.; Chaushu, G.; Becker, A.; Yefenof, E.; Merrick, J.; Chaushu, S.

    2006-01-01

    Background: Periodontal disease in Down's syndrome (DS) individuals develops earlier and is more rapid and extensive than in age-matched normal individuals. The present study evaluated a group of DS patients, who had been participating in a 10-year preventive dental programme, for the impact of the programme on their periodontal status. Methods:…

  8. Treating aggressive periodontitis.

    PubMed

    Bowen, Denise M

    2011-01-01

    The purpose of Linking Research to Clinical Practice is to present evidence based information to clinical dental hygienists so that they can make informed decisions regarding patient treatment and recommendations. Each issue will feature a different topic area of importance to clinical dental hygienists with A BOTTOM LINE to translate the research findings into clinical application.

  9. Impact of metronidazole and amoxicillin combination on matrix metalloproteinases-1 and tissue inhibitors of matrix metalloproteinases balance in generalized aggressive periodontitis

    PubMed Central

    Cifcibasi, Emine; Kantarci, Alpdogan; Badur, Selim; Issever, Halim; Cintan, Serdar

    2015-01-01

    Objective: Generalized aggressive periodontitis (GAgP) is a complex periodontal disease affecting the entire dentition with a rapid destruction of the periodontium and resulting in loss of teeth. We hypothesized that better clinical healing of adjunctive use of amoxicillin plus metronidazole combination may be related to the effect of this combination therapy to restore imbalance between matrix metalloproteinases (MMP) and their tissue inhibitors (TIMP) which is associated with connective tissue and alveolar bone destruction in patients with GAgP. Materials and Methods: Twenty-eight subjects diagnosed with GAgP were recruited. Patients were randomly assigned to test or control groups. MMP-1/TIMP-1 ratio was compared between groups receiving scaling and root planning (SRP) alone (control) or in combination with amoxicillin plus metronidazole (test). Clinical periodontal variables were measured. Gingival crevicular fluid samples were obtained and analyzed for MMP-1 and TIMP-1. Measurements were taken at baseline and repeated at 3 and 6 months after therapy. Results: Total MMP-1 levels were significantly decreased in both groups (P < 0.05) at 3 and 6 months. MMP-1 concentration levels showed a similar pattern to MMP-1 total levels decreasing significantly at 3 months (P < 0.05). TIMP-1 concentration levels increased in the test group throughout the study period, while the difference did not reach statistical significance (P > 0.05). TIMP-1/MMP-1 balance was restored in test group at 6 months significantly better than the control group (P < 0.05). Conclusion: The results of this study suggest that metronidazole and amoxicillin combination as an adjunct to SRP results in better clinical healing through restoring TIMP-1/MMP-1 balance. PMID:25713485

  10. Replication of the association of chromosomal region 9p21.3 with generalized aggressive periodontitis (gAgP) using an independent case-control cohort

    PubMed Central

    2010-01-01

    Background The human chromosomal region 9p21.3 has been shown to be strongly associated with Coronary Heart Disease (CHD) in several Genome-wide Association Studies (GWAS). Recently, this region has also been shown to be associated with Aggressive Periodontitis (AgP), strengthening the hypothesis that the established epidemiological association between periodontitis and CHD is caused by a shared genetic background, in addition to common environmental and behavioural risk factors. However, the size of the analyzed cohorts in this primary analysis was small compared to other association studies on complex diseases. Using our own AgP cohort, we attempted to confirm the described associations for the chromosomal region 9p21.3. Methods We analyzed our cohort consisting of patients suffering from the most severe form of AgP, generalized AgP (gAgP) (n = 130) and appropriate periodontally healthy control individuals (n = 339) by genotyping four tagging SNPs (rs2891168, rs1333042, rs1333048 and rs496892), located in the chromosomal region 9p21.3, that have been associated with AgP. Results The results confirmed significant associations between three of the four SNPs and gAgP. The combination of our results with those from the study which described this association for the first time in a meta-analysis of the four tagging SNPs produced clearly lower p-values compared with the results of each individual study. According to these results, the most plausible genetic model for the association of all four tested SNPs with gAgP seems to be the multiplicative one. Conclusion We positively replicated the finding of an association between the chromosomal region 9p21.3 and gAgP. This result strengthens support for the hypothesis that shared susceptibility genes within this chromosomal locus might be involved in the pathogenesis of both CHD and gAgP. PMID:20696043

  11. [Sample German LAPS.

    ERIC Educational Resources Information Center

    Rosenthal, Bianca

    Four learning activity packages (LAPS) for use in secondary school German programs contain instructional materials which enable students to improve their basic linguistic skills. The units include: (1) "Grusse," (2) "Ich Heisse...Namen," (3) "Tune into Your Career: Business Correspondence 'Auf Deutch'," and (4) "Understanding German Culture."…

  12. Macrophage Inflammatory Protein-1α Shows Predictive Value as a Risk Marker for Subjects and Sites Vulnerable to Bone Loss in a Longitudinal Model of Aggressive Periodontitis

    PubMed Central

    Fine, Daniel H.; Markowitz, Kenneth; Fairlie, Karen; Tischio-Bereski, Debbie; Ferrandiz, Javier; Godboley, Dipti; Furgang, David; Gunsolley, John; Best, Al

    2014-01-01

    Improved diagnostics remains a fundamental goal of biomedical research. This study was designed to assess cytokine biomarkers that could predict bone loss (BL) in localized aggressive periodontitis. 2,058 adolescents were screened. Two groups of 50 periodontally healthy adolescents were enrolled in the longitudinal study. One group had Aggregatibacter actinomycetemcomitans (Aa), the putative pathogen, while the matched cohort did not. Cytokine levels were assessed in saliva and gingival crevicular fluid (GCF). Participants were sampled, examined, and radiographed every 6 months for 2–3 years. Disease was defined as radiographic evidence of BL. Saliva and GCF was collected at each visit, frozen, and then tested retrospectively after detection of BL. Sixteen subjects with Aa developed BL. Saliva from Aa-positive and Aa-negative healthy subjects was compared to subjects who developed BL. GCF was collected from 16 subjects with BL and from another 38 subjects who remained healthy. GCF from BL sites in the 16 subjects was compared to healthy sites in these same subjects and to healthy sites in subjects who remained healthy. Results showed that cytokines in saliva associated with acute inflammation were elevated in subjects who developed BL (i.e., MIP-1α MIP-1β IL-α, IL-1β and IL-8; p<0.01). MIP-1α was elevated 13-fold, 6 months prior to BL. When MIP-1α levels were set at 40 pg/ml, 98% of healthy sites were below that level (Specificity); whereas, 93% of sites with BL were higher (Sensitivity), with comparable Predictive Values of 98%; p<0.0001; 95% C.I. = 42.5–52.7). MIP-1α consistently showed elevated levels as a biomarker for BL in both saliva and GCF, 6 months prior to BL. MIP-1α continues to demonstrate its strong candidacy as a diagnostic biomarker for both subject and site vulnerability to BL. PMID:24901458

  13. Rubicon swaps autophagy for LAP.

    PubMed

    Boyle, Keith B; Randow, Felix

    2015-07-01

    Phagocytic cells engulf their prey into vesicular structures called phagosomes, of which a certain proportion becomes demarcated for enhanced maturation by a process called LC3-associated phagocytosis (LAP). Light has now been shed on the molecular requirements of LAP, establishing a central role for the protein Rubicon in the immune response to Aspergillus fumigatus.

  14. Tumor necrosis factor-α G-308A (rs1800629) polymorphism and aggressive periodontitis susceptibility: a meta-analysis of 16 case-control studies.

    PubMed

    Wei, Xue-Mei; Chen, Yong-Ji; Wu, Lan; Cui, Li-Jun; Hu, Ding-Wei; Zeng, Xian-Tao

    2016-01-11

    Association between tumor necrosis factor-α (TNF-α) G-308A (rs1800629) polymorphism and susceptibility to aggressive periodontitis (AgP) were inconsistent, hence we performed this meta-analysis to clarify the association between them using Comprehensive Meta-Analysis v2.2 software. 16 case-control studies were searched from the PubMed, Embase and CNKI databases up to February 2, 2015. The meta-analysis showed a significantly increased risk in A vs. G (OR = 1.23, 95%CI = 1.04-1.44), AA vs. GG (OR = 2.07, 95%CI = 1.11-3.87), and AA vs. AG+GG genetic models (OR = 2.09, 95%CI = 1.13-3.86); however, the non-significantly increased risk was shown in AG vs. GG (OR = 1.06, 95%CI = 0.85-1.32) and AA+AG vs. GG genetic models (OR = 1.06, 95%CI = 0.85-1.31). Cumulative analysis showed that the association changed from non-significant to significant with new studies accumulated and the CIs became more and more narrow, sensitivity analysis indicated results were statistically robust. Stratified analyses of confirmed of HWE, Asians, Caucasians, and population-based controls obtained results similar to that of overall analysis. There was no evidence of publication bias. In summary, current evidence demonstrates that TNF-a G-308A polymorphism might be associated with AgP susceptibility, especially in Asians and Caucasians.

  15. Cashier/Checker Learning Activity Packets (LAPs).

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    Twenty-four learning activity packets (LAPs) are provided for six areas of instruction in a cashier/checker program. Section A, Orientation, contains an LAP on exploring the job of cashier-checker. Section B, Operations, has nine LAPs, including those on operating the cash register, issuing trading stamps, and completing the cash register balance…

  16. Periodontal Diseases

    MedlinePlus

    ... Diseases Small Text Medium Text Large Text Periodontal Diseases Periodontal diseases are disorders of the gums, or gingiva, and other tissues around the teeth. Periodontal diseases vary in severity, from the reversible, recurring mild ...

  17. Additive manufacturing of tools for lapping glass

    NASA Astrophysics Data System (ADS)

    Williams, Wesley B.

    2013-09-01

    Additive manufacturing technologies have the ability to directly produce parts with complex geometries without the need for secondary processes, tooling or fixtures. This ability was used to produce concave lapping tools with a VFlash 3D printer from 3D Systems. The lapping tools were first designed in Creo Parametric with a defined constant radius and radial groove pattern. The models were converted to stereolithography files which the VFlash used in building the parts, layer by layer, from a UV curable resin. The tools were rotated at 60 rpm and used with 120 grit and 220 grit silicon carbide lapping paste to lap 0.750" diameter fused silica workpieces. The samples developed a matte appearance on the lapped surface that started as a ring at the edge of the workpiece and expanded to the center. This indicated that as material was removed, the workpiece radius was beginning to match the tool radius. The workpieces were then cleaned and lapped on a second tool (with equivalent geometry) using a 3000 grit corundum aluminum oxide lapping paste, until a near specular surface was achieved. By using lapping tools that have been additively manufactured, fused silica workpieces can be lapped to approach a specified convex geometry. This approach may enable more rapid lapping of near net shape workpieces that minimize the material removal required by subsequent polishing. This research may also enable development of new lapping tool geometry and groove patterns for improved loose abrasive finishing.

  18. How Tongue Size and Roughness Affect Lapping

    NASA Astrophysics Data System (ADS)

    Hubbard, M. J.; Hay, K. M.

    2012-10-01

    The biomechanics of domestic cat lapping (Felis catus) and domestic dog lapping (Canis familiaris) is currently under debate. Lapping mechanics in vertebrates with incomplete cheeks, such as cats and dogs, is a balance of inertia and the force of gravity likely optimized for ingestion and physical necessities. Physiology dictates vertebrate mass, which dictates vertebrate tongue size, which dictates lapping mechanics to achieve optimum liquid ingestion; with either touch lapping, scooping, or a hybrid lapping method. The physics of this optimized system then determines how high a column of liquid can be raised before it collapses due to gravity, and therefore, lapping frequency. Through tongue roughness model variation experiments it was found that pore-scale geometrical roughness does not appear to affect lapping or liquid uptake. Through tongue size model variation experiments it was found that there is a critical tongue radius in the range of 25 mm to 35 mm above which touch lapping is no longer an efficient way to uptake liquid. Vertebrates with incomplete cheeks may use a touch lapping method to ingest water if their tongue radius is less than this critical radius and use an alternative ingestion method if their tongue radius is larger.

  19. Quadruple Lap Shear Processing Evaluation

    NASA Technical Reports Server (NTRS)

    Thornton, Tony N.; McCool, A. (Technical Monitor)

    2000-01-01

    The Thiokol, Science and Engineering Huntsville Operations (SEHO) Laboratory has previously experienced significant levels of variation in testing Quadruple Lap Shear (QLS) specimens. The QLS test is used at Thiokol / Utah for the qualification of Reusable Solid Rocket Motor (RSRM) nozzle flex bearing materials. A test was conducted to verify that process changes instituted by SEHO personnel effectively reduced variability, even with normal processing variables introduced. A test matrix was designed to progress in a series of steps; the first establishing a baseline, then introducing additional solvents or other variables. Variables included normal test plan delay times, pre-bond solvent hand-wipes and contaminants. Each condition tested utilized standard QLS hardware bonded with natural rubber, two separate technicians and three replicates. This paper will report the results and conclusions of this investigation.

  20. Risk factors for periodontal disease.

    PubMed

    Genco, Robert J; Borgnakke, Wenche S

    2013-06-01

    Risk factors play an important role in an individual's response to periodontal infection. Identification of these risk factors helps to target patients for prevention and treatment, with modification of risk factors critical to the control of periodontal disease. Shifts in our understanding of periodontal disease prevalence, and advances in scientific methodology and statistical analysis in the last few decades, have allowed identification of several major systemic risk factors for periodontal disease. The first change in our thinking was the understanding that periodontal disease is not universal, but that severe forms are found only in a portion of the adult population who show abnormal susceptibility. Analysis of risk factors and the ability to statistically adjust and stratify populations to eliminate the effects of confounding factors have allowed identification of independent risk factors. These independent but modifiable, risk factors for periodontal disease include lifestyle factors, such as smoking and alcohol consumption. They also include diseases and unhealthy conditions such as diabetes mellitus, obesity, metabolic syndrome, osteoporosis, and low dietary calcium and vitamin D. These risk factors are modifiable and their management is a major component of the contemporary care of many periodontal patients. Genetic factors also play a role in periodontal disease and allow one to target individuals for prevention and early detection. The role of genetic factors in aggressive periodontitis is clear. However, although genetic factors (i.e., specific genes) are strongly suspected to have an association with chronic adult periodontitis, there is as yet no clear evidence for this in the general population. It is important to pursue efforts to identify genetic factors associated with chronic periodontitis because such factors have potential in identifying patients who have a high susceptibility for development of this disease. Many of the systemic risk factors

  1. CrossLaps and beta-glucuronidase in peri-implant and gingival crevicular fluid.

    PubMed

    Schubert, U; Kleber, B M; Strietzel, F P; Dörfling, P

    2001-01-01

    Collagen degradation products of the carboxyterminal region possibly reflect bone and attachment loss. In the present study, the Serum CrossLaps One-Step enzyme-linked immunosorbent assay was used to determine a specific part of the carboxyterminal region of type I collagen, the CrossLaps. Samples of peri-implant and gingival crevicular fluid of 111 implants and 53 teeth from 47 partially or completely edentulous patients were examined in reference to levels of CrossLaps and beta-glucuronidase (beta G), an established marker of periodontal disease. Clinical probing pocket depth (PPD), bleeding on probing (BOP), plaque accumulation, mobility, radiographic bone loss, and the occurrence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia were assessed. The mean values were: for PPD at implants 3.76 +/- 1.41 mm, at teeth 3.44 +/- 0.88 mm; for beta G at implants 0.364 +/- 0.392 pU/min, at teeth 0.314 +/- 0.209 pU/min; for CrossLaps at implants 0.069 +/- 0.059 pmol/min, at teeth 0.082 +/- 0.053 pmol/min. Bleeding on probing was significantly higher on implants than on teeth (McNemar test, P = .004). No significant difference of beta G levels was found between teeth and implants (Wilcoxon test). A negative correlation was found between beta G levels and CrossLaps levels at teeth (Pearson-rank correlation, P = .002). On implants, no significant correlation of these 2 parameters was seen, but significant correlations were found between sulcus fluid flow rate and PPD (P = .012), beta G levels and bone loss (P < 0.0005), and CrossLaps levels and PPD (P = .011). CrossLaps can be detected in both gingival and peri-implant crevicular fluid. While rising levels of beta G may indicate acute peri-implantitis, CrossLaps may not, but could play a role as a marker of ongoing attachment loss.

  2. The Effect of Surface Irregularities on Wing Drag. II - Lap Joints. 2; Lap Joints

    NASA Technical Reports Server (NTRS)

    Hood, Manley J.

    1938-01-01

    Tests have been made in the NACA 8-foot high-speed wind tunnel of the drag caused by four types of lap joint. The tests were made on an airfoil of NACA 23012 section and 5-foot chord and covered in a range of speeds from 80 to 500 miles per hour and lift coefficients from 0 to 0.30. The increases in profile drag caused by representative arrangements of laps varied from 4 to 9%. When there were protruding rivet heads on the surface, the addition of laps increased the drag only slightly. Laps on the forward part of a wing increased the drag considerably more than those farther back.

  3. Iatrogenic Damage to the Periodontium Caused by Periodontal Treatment Procedures

    PubMed Central

    Latheef, P; Sirajuddin, Syed; Gundapaneni, Veenadharini; MN, Kumuda; Apine, Ashwini

    2015-01-01

    Periodontitis is an inflammatory disease affecting the periodontium i.e. the tissues that surround and support the teeth. Periodontitis manifests as progressive loss of the alveolar bone around the teeth, and if left untreated, can cause loosening and subsequent loss of teeth. Periodontitis is initiated by microorganisms that adhere to and grow on the tooth's surfaces, besides an over -aggressive immune response against these microorganisms. The primary goal of periodontal therapy is to preserve the natural dentition by accomplishing and preserving a healthy functional periodontium. Many treatment modalities have been introduced to improve the therapeutic result of periodontal treatment which may also damage the periodontiumiatrogenically. PMID:26312087

  4. LAPS Grid generation and adaptation

    NASA Astrophysics Data System (ADS)

    Pagliantini, Cecilia; Delzanno, Gia Luca; Guo, Zehua; Srinivasan, Bhuvana; Tang, Xianzhu; Chacon, Luis

    2011-10-01

    LAPS uses a common-data framework in which a general purpose grid generation and adaptation package in toroidal and simply connected domains is implemented. The initial focus is on implementing the Winslow/Laplace-Beltrami method for generating non-overlapping block structured grids. This is to be followed by a grid adaptation scheme based on Monge-Kantorovich optimal transport method [Delzanno et al., J. Comput. Phys,227 (2008), 9841-9864], that equidistributes application-specified error. As an initial set of applications, we will lay out grids for an axisymmetric mirror, a field reversed configuration, and an entire poloidal cross section of a tokamak plasma reconstructed from a CMOD experimental shot. These grids will then be used for computing the plasma equilibrium and transport in accompanying presentations. A key issue for Monge-Kantorovich grid optimization is the choice of error or monitor function for equi-distribution. We will compare the Operator Recovery Error Source Detector (ORESD) [Lapenta, Int. J. Num. Meth. Eng,59 (2004) 2065-2087], the Tau method and a strategy based on the grid coarsening [Zhang et al., AIAA J,39 (2001) 1706-1715] to find an ``optimal'' grid. Work supported by DOE OFES.

  5. Periodontal Microbiology.

    PubMed

    Harvey, John D

    2017-04-01

    This article provides a review of current information about periodontal bacteria, their activities within dental plaque biofilm, their interactions with the host immune system, and the infections with which they are associated. Periodontal disease, plaque formation, and the host immune response are also discussed, as are antimicrobial measures used to control the bacteria and the disease.

  6. Automated system for periodontal disease diagnosis

    NASA Astrophysics Data System (ADS)

    Albalat, Salvador E.; Alcaniz-Raya, Mariano L.; Juan, M. Carmen; Grau Colomer, Vincente; Monserrat, Carlos

    1997-04-01

    Evolution of periodontal disease is one of the most important data for the clinicians in order to achieve correct planning and treatment. Clinical measure of the periodontal sulcus depth is the most important datum to know the exact state of periodontal disease. These measures must be done periodically study bone resorption evolution around teeth. Time factor of resorption indicates aggressiveness of periodontitis. Manual probes are commonly used with direct reading. Mechanical probes give automatic signal but this method uses complicated and heavy probes that are only limited for University researchers. Probe position must be the same to have right diagnosis. Digital image analysis of periodontal probing provides practical, accurate and easy tool. Gum and plaque index could also be digitally measured with this method.

  7. Periodontal diseases of children and adolescents.

    PubMed

    Califano, Joseph V

    Children and adolescents are subject to several periodontal diseases. Although there is a much lower prevalence of destructive periodontal diseases in children than in adults, children can develop severe forms of periodontitis. In some cases, this destructive disease is a manifestation of a known underlying systemic disease. In other young patients, the underlying cause for increased susceptibility and early onset of disease is unknown. These diseases are often familial, suggesting a genetic predisposition for aggressive disease. Current modalities for managing periodontal diseases of children and adolescents may include antibiotic therapy in combination with non-surgical and/or surgical therapy. Since early diagnosis ensures the greatest chance for successful treatment, it is important that children receive a periodontal examination as part of their routine dental visits.

  8. Scope of photodynamic therapy in periodontics.

    PubMed

    Kumar, Vivek; Sinha, Jolly; Verma, Neelu; Nayan, Kamal; Saimbi, C S; Tripathi, Amitandra K

    2015-01-01

    Periodontal disease results from inflammation of the supporting structure of the teeth and in response to chronic infection caused by various periodontopathic bacteria. The mechanical removal of this biofilm and adjunctive use of antibacterial disinfectants and antibiotics have been the conventional methods of periodontal therapy. However, the removal of plaque and the reduction in the number of infectious organisms can be impaired in sites with difficult access. Photodynamic therapy (PDT) is a powerful laser-initiated photochemical reaction, involving the use of a photoactive dye (photosensitizer) activated by light of a specific wavelength in the presence of oxygen. Application of PDT in periodontics such as pocket debridement, gingivitis, and aggressive periodontitis continue to evolve into a mature clinical treatment modality and is considered as a promising novel approach for eradicating pathogenic bacteria in periodontitis.

  9. Periodontal regeneration.

    PubMed

    Wang, Hom-Lay; Greenwell, Henry; Fiorellini, Joseph; Giannobile, William; Offenbacher, Steven; Salkin, Leslie; Townsend, Cheryl; Sheridan, Phillip; Genco, Robert J

    2005-09-01

    Untreated periodontal disease leads to tooth loss through destruction of the attachment apparatus and tooth-supporting structures. The goals of periodontal therapy include not only the arrest of periodontal disease progression,but also the regeneration of structures lost to disease where appropriate. Conventional surgical approaches (e.g., flap debridement) continue to offer time-tested and reliable methods to access root surfaces,reduce periodontal pockets, and attain improved periodontal form/architecture. However, these techniques offer only limited potential towards recovering tissues destroyed during earlier disease phases. Recently, surgical procedures aimed at greater and more predictable regeneration of periodontal tissues and functional attachment close to their original level have been developed, analyzed, and employed in clinical practice. This paper provides a review of the current understanding of the mechanisms, cells, and factors required for regeneration of the periodontium and of procedures used to restore periodontal tissues around natural teeth. Targeted audiences for this paper are periodontists and/or researchers with an interest in improving the predictability of regenerative procedures. This paper replaces the version published in 1993.

  10. Periodontal maintenance.

    PubMed

    Tan, A E S

    2009-09-01

    The main goal of periodontal therapy is to establish an oral environment compatible with periodontal health by the physical disruption of the plaque biofilm and adjunctive chemical means if required. Implicit in this objective is the ongoing requirement of detection and interception of new and recurrent disease, which continues at selected intervals for the life of the dentition after the initial ("active") phase of periodontal treatment. This concept of ongoing periodontal maintenance therapy has been embraced as the mandatory requirement for favourable periodontal outcomes based on institutional clinical trials and in practice-based studies in various parts of the world. This review examines the ramifications of periodontal maintenance therapy based upon a multi-level assessment of logistic issues and risk factors at three levels: (1) The patient level - treatment time; patient attendance compliance; and homecare measures, antiseptics/antibiotics and smoking. (2) The level of the individual tooth - tooth loss; and evaluation of success versus survival. (3) The level of each tooth surface ("site") - probing depth, loss of attachment and bleeding on probing; and changes in clinical attachment levels. In spite of the diversity of studies conducted, there is agreement on the efficacy of periodontal maintenance therapy when compared with studies on untreated populations and in treated cases that were not maintained.

  11. LAPS discretization and solution of plasma equilibrium

    NASA Astrophysics Data System (ADS)

    Missanelli, Maria; Delzanno, Gian Luca; Guo, Zehua; Srinivasan, Bhuvana; Tang, Xianzhu

    2011-10-01

    LAPS provides spectral element discretization for solving steady state plasma profiles. Our initial focus is on its implementation for two dimensional open magnetic field equilibria in linear and toroidal geometries. The linear geometry is an axisymmetric magnetic mirror with anisotropic pressure. The toroidal case is a tokamak scrape-off layer plasma. Structured grids are produced by the grid generation package in LAPS. The spectral element discretization uses modal bases over quadrilateral elements. A Newton-Krylov solver implemented with the Portable, Extensible Toolkits for Scientific Computing PETSc is applied to iteratively converge the solution. Care has been taken in the code design to separate the grid generation, spectral element discretization, and (non)linear solver from the user-specified equilibrium equations, so the LAPS infrastructure can be easily used for different applications. Work supported by DOE OFES.

  12. An orientation-selective orthogonal lapped transform.

    PubMed

    Kunz, Dietmar

    2008-08-01

    A novel critically sampled orientation-selective orthogonal lapped transform called the lapped Hartley transform (LHT) is derived. In a first step, overlapping basis functions are generated by modulating basis functions of a 2-D block Hartley transform by a cosine wave. To achieve invertibility and orthogonality, an iterative filter is applied as prefilter in the analysis and as postfilter in the synthesis operation, respectively. Alternatively, filtering can be restricted to analysis or synthesis, ending up with a biorthogonal transform (LHT-PR, LHT-PO). A statistical analysis based on a 4000-image data base shows that the LHT and LHT-PO have better redundancy removal properties than other block or lapped transforms. Finally, image compression and noise removal examples are given, showing the advantages of the LHT especially in images containing oriented textures.

  13. Experimental study of lap splice bolted connection

    NASA Astrophysics Data System (ADS)

    Zhao, Dehui; Tian, Lishan; Jiang, Wenqiang; An, Liqiang; Zhang, Ziyang

    2017-01-01

    The bolted connection is prone to slip under external load in the lattice transmission tower, which will affect the internal forces and deformation of tower. In order to better simulate the effect of bolt connection slippage on transmission tower, the load deformation relationship should be established. In this paper, the single lap splice bolt connection under tension load is tested and the load displacement curve is obtained. Furthermore, the existing model of single lap splice bolted connection is modified, which will plays an important role in the influence of the bolt slippage of the transmission lines towers more accurately and reasonably.

  14. Periodontal materials.

    PubMed

    Darby, I

    2011-06-01

    Periodontics is more associated with debridement of periodontal pockets and not generally thought of as using dental materials in the treatment of patients. However, the last 30 years have seen the development of materials used in regeneration of the periodontal tissues following periodontal disease, guided tissue regeneration, and the use of these materials in bone regeneration more recently, guided bone regeneration. The materials used include bone grafts and membranes, but also growth factors and cells-based therapies. This review provides an overview of the materials currently used and looks at contemporary research with a view to what may be used in the future. It also looks at the clinical effectiveness of these regenerative therapies with an emphasis on what is available in Australia.

  15. Nonsurgical periodontal therapy.

    PubMed

    Drisko, C H

    2001-01-01

    reports, however, would indicate that, when daily irrigation with water was added to a regular oral hygiene home regimen, a significant reduction in probing depth, bleeding on probing and Gingival Index was observed. A significant reduction in cytokine levels (interleukin-1beta and prostaglandin E2, which are associated with destructive changes in inflamed tissues and bone resorption also occurs. If patient-applied antimicrobial therapy is insufficient in preventing, arresting, or reversing the disease progression, then professionally applied antimicrobial agents should be considered including sustained local drug delivery products. Other, more broadly based pharmacotherapeutic agents may be indicated for multiple failing sites. Such agents would include systemic antibiotics or host modulating drugs used in conjunction with periodontal debridement. More aggressive types of juvenile periodontitis or severe rapidly advancing adult periodontitis usually require a combination of surgical intervention in conjunction with systemic antibiotics and generally are not controlled with nonsurgical anti-infective therapy alone. It should be noted, however, that, to date, no home care products or devices currently available can completely control or eliminate the pathogenic plaques associated with periodontal diseases for extended periods of time. Daily home care and frequent recall are still paramount for long-term success. Nonsurgical therapy remains the cornerstone of periodontal treatment. Attention to detail, patient compliance and proper selection of adjunctive antimicrobial agents for sustained plaque control are important elements in achieving successful long-term results. Frequent re-evaluation and careful monitoring allows the practitioner the opportunity to intervene early in the disease state, to reverse or arrest the progression of periodontal disease with meticulous nonsurgical anti-infective therapy.

  16. 49 CFR 230.30 - Lap-joint seam boilers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Lap-joint seam boilers. 230.30 Section 230.30..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Inspection and Repair § 230.30 Lap-joint seam boilers. Every boiler having lap-joint longitudinal...

  17. 49 CFR 230.30 - Lap-joint seam boilers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Lap-joint seam boilers. 230.30 Section 230.30..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Inspection and Repair § 230.30 Lap-joint seam boilers. Every boiler having lap-joint longitudinal...

  18. 49 CFR 230.30 - Lap-joint seam boilers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Lap-joint seam boilers. 230.30 Section 230.30..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Inspection and Repair § 230.30 Lap-joint seam boilers. Every boiler having lap-joint longitudinal...

  19. 49 CFR 230.30 - Lap-joint seam boilers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Lap-joint seam boilers. 230.30 Section 230.30..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Inspection and Repair § 230.30 Lap-joint seam boilers. Every boiler having lap-joint longitudinal...

  20. 49 CFR 230.30 - Lap-joint seam boilers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Lap-joint seam boilers. 230.30 Section 230.30..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Inspection and Repair § 230.30 Lap-joint seam boilers. Every boiler having lap-joint longitudinal...

  1. Periodontal health status in a colony of 109 cats.

    PubMed

    Girard, Nicolas; Servet, Eric; Biourge, Vincent; Hennet, Philippe

    2009-01-01

    Periodontal disease has not been well characterized in the cat, and it is not known if feline tooth resorptions (TR) are equivalent to those observed in humans and dogs. The aim of this study was to investigate the different patterns of periodontal inflammation in cats, and to evaluate their prevalence in a standardized healthy population (n = 109). Particular emphasis was placed on the potential associations between TR and periodontal parameters, as well as the influence of potential risk factors (including breed, sex, and age). A single complete periodontal examination was performed, including periodontal probing of each tooth and exploration of the tooth surface using a dental explorer; at least 10 radiographs were taken for each cat. Missing teeth with radiographic evidence of root apices were present in 34.0% of cats. Periodontal disease was common, and 13.0% of cats had aggressive periodontitis. All of the cats had some form of periodontal inflammation, and only 4.0% of cats were free from gingival inflammation. Moderate to severe gingivitis was present in 13.0% of teeth. Dental furcation exposure was present in 18.0% of all multi-rooted teeth. Periodontal bone loss was observed in 31.2% of teeth, with the majority (98.2%) of all cats having some form of periodontal bone loss. Breed effects were identified for some variables. Eight of 14 periodontal variables were statistically correlated with Type 1 TR. Two of 14 variables (and age) were statistically correlated with Type 2 TR. In conclusion, the cats of this colony had a wide range of periodontal inflammation, including aggressive periodontitis. Type 1 TR and Type 2 TR were identified to be two significantly different manifestations of TR, with a strong association between Type 1 TR and periodontal disease.

  2. Nucleation kinetics, growth and characterization of dLAP, dLAP:KF and dLAP:NaN 3 crystals

    NASA Astrophysics Data System (ADS)

    Hameed, A. S. Haja; Ravi, G.; Jayavel, R.; Ramasamy, P.

    2003-03-01

    The nucleation parameters, such as interfacial tension, radius of the critical nucleus and critical free energy change have been estimated for deuterated L-arginine phosphate (dLAP), potassium fluoride mixed dLAP and sodium azide mixed dLAP single crystals. Pure and additive mixed dLAP single crystals are grown by slow cooling technique. The effect of microbial contamination and colouration on the growth solutions has been studied. The crystalline powder of the grown crystals has been examined by X-ray diffraction and thermal analyses in order to estimate the lattice parameters and study thermal properties respectively.

  3. Large-scale Advanced Propfan (LAP) program

    NASA Technical Reports Server (NTRS)

    Sagerser, D. A.; Ludemann, S. G.

    1985-01-01

    The propfan is an advanced propeller concept which maintains the high efficiencies traditionally associated with conventional propellers at the higher aircraft cruise speeds associated with jet transports. The large-scale advanced propfan (LAP) program extends the research done on 2 ft diameter propfan models to a 9 ft diameter article. The program includes design, fabrication, and testing of both an eight bladed, 9 ft diameter propfan, designated SR-7L, and a 2 ft diameter aeroelastically scaled model, SR-7A. The LAP program is complemented by the propfan test assessment (PTA) program, which takes the large-scale propfan and mates it with a gas generator and gearbox to form a propfan propulsion system and then flight tests this system on the wing of a Gulfstream 2 testbed aircraft.

  4. C-reactive protein as a marker of periodontal disease.

    PubMed

    Kanaparthy, Rosaiah; Kanaparthy, Aruna; Mahendra, Muktishree

    2012-01-01

    Periodontal subgingival pathogens affect local and systemic immune and inflammatory response and cause the release of cytokines; this results in periodontal destruction and initiation of an acute phase systemic inflammatory response characterized by the release of C-reactive proteins (CRP). This study set out to evaluate the serum concentration of CRP that can be used as a marker of periodontal disease as well as a risk indicator for cardiovascular disease. Based on their periodontal status, 45 patients were divided into three groups. The following clinical parameters were recorded: plaque index, gingival index, bleeding index, probing pocket depth, and clinical attachment levels. Scoring was done on six tooth surfaces for all teeth. For the CRP assessment, blood samples were collected from subjects at the time of clinical examination. The results indicated an increase in serum CRP levels in patients with generalized aggressive periodontitis and chronic periodontitis as compared to controls.

  5. Gum (Periodontal) Disease

    MedlinePlus

    ... of this page please turn Javascript on. Gum (Periodontal) Disease What Is Gum (Periodontal) Disease? An Infection of the Gums and Surrounding Tissues Gum (periodontal) disease is an infection of the gums and surrounding ...

  6. Homologs of the LapD-LapG c-di-GMP Effector System Control Biofilm Formation by Bordetella bronchiseptica

    PubMed Central

    Ambrosis, Nicolás; Boyd, Chelsea D.; O´Toole, George A.; Fernández, Julieta; Sisti, Federico

    2016-01-01

    Biofilm formation is important for infection by many pathogens. Bordetella bronchiseptica causes respiratory tract infections in mammals and forms biofilm structures in nasal epithelium of infected mice. We previously demonstrated that cyclic di-GMP is involved in biofilm formation in B. bronchiseptica. In the present work, based on their previously reported function in Pseudomonas fluorescens, we identified three genes in the B. bronchiseptica genome likely involved in c-di-GMP-dependent biofilm formation: brtA, lapD and lapG. Genetic analysis confirmed a role for BrtA, LapD and LapG in biofilm formation using microtiter plate assays, as well as scanning electron and fluorescent microscopy to analyze the phenotypes of mutants lacking these proteins. In vitro and in vivo studies showed that the protease LapG of B. bronchiseptica cleaves the N-terminal domain of BrtA, as well as the LapA protein of P. fluorescens, indicating functional conservation between these species. Furthermore, while BrtA and LapG appear to have little or no impact on colonization in a mouse model of infection, a B. bronchiseptica strain lacking the LapG protease has a significantly higher rate of inducing a severe disease outcome compared to the wild type. These findings support a role for c-di-GMP acting through BrtA/LapD/LapG to modulate biofilm formation, as well as impact pathogenesis, by B. bronchiseptica PMID:27380521

  7. Dogs lap using acceleration-driven open pumping

    PubMed Central

    Gart, Sean; Socha, John J.; Vlachos, Pavlos P.; Jung, Sunghwan

    2015-01-01

    Dogs lap because they have incomplete cheeks and cannot suck. When lapping, a dog’s tongue pulls a liquid column from the bath, suggesting that the hydrodynamics of column formation are critical to understanding how dogs drink. We measured lapping in 19 dogs and used the results to generate a physical model of the tongue’s interaction with the air–fluid interface. These experiments help to explain how dogs exploit the fluid dynamics of the generated column. The results demonstrate that effects of acceleration govern lapping frequency, which suggests that dogs curl the tongue to create a larger liquid column. Comparing lapping in dogs and cats reveals that, despite similar morphology, these carnivores lap in different physical regimes: an unsteady inertial regime for dogs and steady inertial regime for cats. PMID:26668382

  8. Dogs lap using acceleration-driven open pumping.

    PubMed

    Gart, Sean; Socha, John J; Vlachos, Pavlos P; Jung, Sunghwan

    2015-12-29

    Dogs lap because they have incomplete cheeks and cannot suck. When lapping, a dog's tongue pulls a liquid column from the bath, suggesting that the hydrodynamics of column formation are critical to understanding how dogs drink. We measured lapping in 19 dogs and used the results to generate a physical model of the tongue's interaction with the air-fluid interface. These experiments help to explain how dogs exploit the fluid dynamics of the generated column. The results demonstrate that effects of acceleration govern lapping frequency, which suggests that dogs curl the tongue to create a larger liquid column. Comparing lapping in dogs and cats reveals that, despite similar morphology, these carnivores lap in different physical regimes: an unsteady inertial regime for dogs and steady inertial regime for cats.

  9. Systematic Construction of Real Lapped Tight Frame Transforms

    PubMed Central

    Sandryhaila, Aliaksei; Chebira, Amina; Milo, Christina; Kovčcević, Jelena; Püschel, Markus

    2010-01-01

    We present a constructive algorithm for the design of real lapped equal-norm tight frame transforms. These transforms can be efficiently implemented through filter banks and have recently been proposed as a redundant counterpart to lapped orthogonal transforms, as well as an infinite-dimensional counterpart to harmonic tight frames. The proposed construction consists of two parts: First, we design a large class of new real lapped orthogonal transforms derived from submatrices of the discrete Fourier transform. Then, we seed these to obtain real lapped tight frame transforms corresponding to tight, equal-norm frames. We identify those frames that are maximally robust to erasures, and show that our construction leads to a large class of new lapped orthogonal transforms as well as new lapped tight frame transforms. PMID:20607116

  10. Familial periodontal disease in the Cayo Santiago rhesus macaques.

    PubMed

    Gonzalez, Octavio A; Orraca, Luis; Kensler, Terry B; Gonzalez-Martinez, Janis; Maldonado, Elizabeth; Ebersole, Jeffrey L

    2016-01-01

    Substantial ongoing research continues to explore the contribution of genetics and environment to the onset, extent and severity of periodontal disease(s). Existing evidence supports that periodontal disease appears to have an increased prevalence in family units with a member having aggressive periodontitis. We have been using the nonhuman primate as a model of periodontal disease for over 25 years with these species demonstrating naturally occurring periodontal disease that increases with age. This report details our findings from evaluation of periodontal disease in skulls from 97 animals (5-31 years of age) derived from the skeletons of the rhesus monkeys (Macaca mulatta) on Cayo Santiago. Periodontal disease was evaluated by determining the distance from the base of the alveolar bone defect to the cemento-enamel junction on 1st/2nd premolars and 1st/2nd molars from all four quadrants. The results demonstrated an increasing extent and severity of periodontitis with aging across the population of animals beyond only compensatory eruption. Importantly, irrespective of age, extensive heterogeneity in disease expression was observed among the animals. Linking these variations to multi-generational matriarchal family units supported familial susceptibility of periodontitis. As the current generations of animals that are descendants from these matrilines are alive, studies can be conducted to explore an array of underlying factors that could account for susceptibility or resistance to periodontal disease.

  11. Computer Controller Optical Surfacing (CCOS) lap pressure control system

    NASA Astrophysics Data System (ADS)

    Greenleaf

    1985-09-01

    A rotary lapping system and process is disclosed for producing a controlled pressure gradient, including positive and negative lift, when lapping a workpiece coated with an abrasive slurry liquid with a plurality of grinding pads mounted beneath a rotating lap substrate. To obtain positive and negative lift, the grinding pads are tilted with respectively a positive and negative angle of attack, which hydrodynamically reacts with the abrasive slurry liquid to produce the desired lift. The controlled pressure gradient is further varied by decentering the rotation of lap substrate.

  12. Al-to-Cu Friction Stir Lap Welding

    NASA Astrophysics Data System (ADS)

    Firouzdor, Vahid; Kou, Sindo

    2012-01-01

    Recently, friction stir welding (FSW) has been used frequently to join dissimilar metals, for instance, Al to Mg, Cu, and steel. The formation of brittle intermetallic compounds often severely limits the strength and ductility of the resultant welds. In the present study, Al-to-Cu lap FSW was studied by welding 6061 Al to commercially pure Cu. Conventional lap FSW was modified by butt welding a small piece of Al to the top of Cu, with a slight pin penetration into the bottom of Al. At travel speeds up to 127 mm/min (5 ipm), the modified welds were about twice the joint strength and five to nine times the ductility of the conventional lap welds. In the conventional lap welds, voids were present along the Al-Cu interface, and fracture occurred along the interface in tensile testing. No such voids were observed in the modified lap welds, and fracture occurred through Cu. Thus, as in the case of Al-to-Mg lap FSW recently studied by the authors, modified lap FSW significantly improved the weld quality in Al-to-Cu lap FSW. At the relatively high travel speed of 203 mm/min (8 ipm), however, modified lap FSW was no longer superior because of channel formation.

  13. Aggressive Behavior

    MedlinePlus

    ... Listen Español Text Size Email Print Share Aggressive Behavior Page Content Article Body My child is sometimes very aggressive. What is the best ... once they are quiet and still reinforces this behavior, so your child learns that time out means “quiet and still.” ...

  14. Periodontal regeneration.

    PubMed

    Ivanovski, S

    2009-09-01

    The ultimate goal of periodontal therapy is the regeneration of the tissues destroyed as a result of periodontal disease. Currently, two clinical techniques, based on the principles of "guided tissue regeneration" (GTR) or utilization of the biologically active agent "enamel matrix derivative" (EMD), can be used for the regeneration of intrabony and Class II mandibular furcation periodontal defects. In cases where additional support and space-making requirements are necessary, both of these procedures can be combined with a bone replacement graft. There is no evidence that the combined use of GTR and EMD results in superior clinical results compared to the use of each material in isolation. Great variability in clinical outcomes has been reported in relation to the use of both EMD and GTR, and these procedures can be generally considered to be unpredictable. Careful case selection and treatment planning, including consideration of patient, tooth, site and surgical factors, is required in order to optimize the outcomes of treatment. There are limited data available for the clinical effectiveness of other biologically active molecules, such as growth factors and platelet concentrates, and although promising results have been reported, further clinical trials are required in order to confirm their effectiveness. Current active areas of research are centred on tissue engineering and gene therapy strategies which may result in more predictable regenerative outcomes in the future.

  15. Signaling aggression.

    PubMed

    van Staaden, Moira J; Searcy, William A; Hanlon, Roger T

    2011-01-01

    From psychological and sociological standpoints, aggression is regarded as intentional behavior aimed at inflicting pain and manifested by hostility and attacking behaviors. In contrast, biologists define aggression as behavior associated with attack or escalation toward attack, omitting any stipulation about intentions and goals. Certain animal signals are strongly associated with escalation toward attack and have the same function as physical attack in intimidating opponents and winning contests, and ethologists therefore consider them an integral part of aggressive behavior. Aggressive signals have been molded by evolution to make them ever more effective in mediating interactions between the contestants. Early theoretical analyses of aggressive signaling suggested that signals could never be honest about fighting ability or aggressive intentions because weak individuals would exaggerate such signals whenever they were effective in influencing the behavior of opponents. More recent game theory models, however, demonstrate that given the right costs and constraints, aggressive signals are both reliable about strength and intentions and effective in influencing contest outcomes. Here, we review the role of signaling in lieu of physical violence, considering threat displays from an ethological perspective as an adaptive outcome of evolutionary selection pressures. Fighting prowess is conveyed by performance signals whose production is constrained by physical ability and thus limited to just some individuals, whereas aggressive intent is encoded in strategic signals that all signalers are able to produce. We illustrate recent advances in the study of aggressive signaling with case studies of charismatic taxa that employ a range of sensory modalities, viz. visual and chemical signaling in cephalopod behavior, and indicators of aggressive intent in the territorial calls of songbirds.

  16. Diamond machine tool face lapping machine

    DOEpatents

    Yetter, H.H.

    1985-05-06

    An apparatus for shaping, sharpening and polishing diamond-tipped single-point machine tools. The isolation of a rotating grinding wheel from its driving apparatus using an air bearing and causing the tool to be shaped, polished or sharpened to be moved across the surface of the grinding wheel so that it does not remain at one radius for more than a single rotation of the grinding wheel has been found to readily result in machine tools of a quality which can only be obtained by the most tedious and costly processing procedures, and previously unattainable by simple lapping techniques.

  17. Gingival Tissue Transcriptomes Identify Distinct Periodontitis Phenotypes

    PubMed Central

    Kebschull, M.; Demmer, R.T.; Grün, B.; Guarnieri, P.; Pavlidis, P.; Papapanou, P.N.

    2014-01-01

    The currently recognized principal forms of periodontitis—chronic and aggressive—lack an unequivocal, pathobiology-based foundation. We explored whether gingival tissue transcriptomes can serve as the basis for an alternative classification of periodontitis. We used cross-sectional whole-genome gene expression data from 241 gingival tissue biopsies obtained from sites with periodontal pathology in 120 systemically healthy nonsmokers with periodontitis, with available data on clinical periodontal status, subgingival microbial profiles, and serum IgG antibodies to periodontal microbiota. Adjusted model-based clustering of transcriptomic data using finite mixtures generated two distinct clusters of patients that did not align with the current classification of chronic and aggressive periodontitis. Differential expression profiles primarily related to cell proliferation in cluster 1 and to lymphocyte activation and unfolded protein responses in cluster 2. Patients in the two clusters did not differ with respect to age but presented with distinct phenotypes (statistically significantly different whole-mouth clinical measures of extent/severity, subgingival microbial burden by several species, and selected serum antibody responses). Patients in cluster 2 showed more extensive/severe disease and were more often male. The findings suggest that distinct gene expression signatures in pathologic gingival tissues translate into phenotypic differences and can provide a basis for a novel classification. PMID:24646639

  18. How dogs lap: open pumping driven by acceleration

    NASA Astrophysics Data System (ADS)

    Gart, Sean; Socha, John; Vlachos, Pavlos; Jung, Sunghwan

    2015-11-01

    Dogs drink by lapping because they have incomplete cheeks and cannot suck fluids into the mouth. When lapping, a dog's tongue pulls a liquid column from a bath, which is then swallowed, suggesting that the hydrodynamics of column formation are critical to understanding how dogs drink. We measured the kinematics of lapping from nineteen dogs and used the results to generate a physical model of the tongue's interaction with the air-fluid interface. These experiments with an accelerating rod help to explain how dogs exploit the fluid dynamics of the generated column. The results suggest that effects of acceleration govern lapping frequency, and that dogs curl the tongue ventrally (backwards) and time their bite on the column to increase fluid intake per lap. Comparing lapping in dogs and cats reveals that though they both lap with the same frequency scaling with respect to body mass and have similar morphology, these carnivores lap in different physical regimes: a high-acceleration regime for dogs and a low-acceleration regime for cats.

  19. Learning Activity Package, Chemistry I, (LAP) Study 29.

    ERIC Educational Resources Information Center

    Jones, Naomi

    Presented is a Learning Activity Package (LAP) study concerned with carbon and its compounds. This LAP in chemistry includes a rationale for studying the chemical element of carbon, a list of student objectives (stated in behavioral terms), of activities (reading, laboratory experiments, model construction, etc.), a two-page worksheet, a…

  20. Lapping: Polishing and shear mode grinding

    SciTech Connect

    Brown, N.J.

    1990-02-01

    It is the thesis of this paper that shear mode grinding (SMG), (ductile grinding, nanogrinding, fractureless grinding) is just a particular form of polishing. It may be unique in that it can involve a hard wheel of very precise dimensions compared to the soft laps usually used in polishing. Such a wheel would permit the fabrication of a precision surface on a brittle material such as glass at a precisely located and oriented position on a part. The technological and economic consequences of such a process seem important but the technical obstacles to implementing the technique are for the moment formidable. It is in production in Japan. This paper provides a bit of understanding of that process obtained by making an end run around the obstacles to view the process from the vantage point of lapping. The paper will lay out some of the concepts and terminology necessary to understand the papers that have supplied the real labor to get us to this point. It will refer to parts of this work briefly in passing so the reader who needs the details knows where to look, and for what, in the bibliography appended. 32 refs., 5 figs.

  1. How cats lap: water uptake by Felis catus.

    PubMed

    Reis, Pedro M; Jung, Sunghwan; Aristoff, Jeffrey M; Stocker, Roman

    2010-11-26

    Animals have developed a range of drinking strategies depending on physiological and environmental constraints. Vertebrates with incomplete cheeks use their tongue to drink; the most common example is the lapping of cats and dogs. We show that the domestic cat (Felis catus) laps by a subtle mechanism based on water adhesion to the dorsal side of the tongue. A combined experimental and theoretical analysis reveals that Felis catus exploits fluid inertia to defeat gravity and pull liquid into the mouth. This competition between inertia and gravity sets the lapping frequency and yields a prediction for the dependence of frequency on animal mass. Measurements of lapping frequency across the family Felidae support this prediction, which suggests that the lapping mechanism is conserved among felines.

  2. Position paper: periodontal diseases of children and adolescents.

    PubMed

    Califano, Joseph V

    2003-11-01

    Children and adolescents are subject to several periodontal diseases. Although there is a much lower prevalence of destructive periodontal diseases in children than in adults, children can develop severe forms of periodontitis. In some cases, this destructive disease is a manifestation of a known underlying systemic disease. In other young patients, the underlying cause for increased susceptibility and early onset of disease is unknown. These diseases are often familial, suggesting a genetic predisposition for aggressive disease. Current modalities for managing periodontal diseases of children and adolescents may include antibiotic therapy in combination with non-surgical and/or surgical therapy. Since early diagnosis ensures the greatest chance for successful treatment, it is important that children receive a periodontal examination as part of their routine dental visits.

  3. Tubular lap joints for wind turbine applications

    SciTech Connect

    Reedy, E.D. Jr.; Guess, T.R.

    1990-01-01

    A combined analytical/experimental study of the strength of thick- walled, adhesively bonded PMMA-to-aluminum and E-glass/epoxy composite-to-aluminum tubular lap joints under axial load has been conducted. Test results include strength and failure mode data. Moreover, strain gages placed along the length of the outer tubular adherend characterize load transfer from one adherend to the other. The strain gage data indicate that load transfer is nonuniform and that the relatively compliant PMMA has the shorter load transfer length. Strains determined by a finite element analysis of the tested joints are in excellent agreement with those measured. Calculated bond stresses are highest in the region of observed failure, and extensive bond yielding is predicted in the E- glass/epoxy composite-to-aluminum joint prior to joint failure. 4 refs., 13 figs., 1 tab.

  4. Flaw Tolerance In Lap Shear Brazed Joints. Part 2

    NASA Technical Reports Server (NTRS)

    Wang, Len; Flom, Yury

    2003-01-01

    This paper presents results of the second part of an on-going effort to gain better understanding of defect tolerance in braze joints. In the first part of this three-part series, we mechanically tested and modeled the strength of the lap joints as a function of the overlap distance. A failure criterion was established based on the zone damage theory, which predicts the dependence of the lap joint shear strength on the overlap distance, based on the critical size of a finite damage zone or an overloaded region in the joint. In this second part of the study, we experimentally verified the applicability of the damage zone criterion on prediction of the shear strength of the lap joint and introduced controlled flaws into the lap joints. The purpose of the study was to evaluate the lap joint strength as a function of flaw size and its location through mechanical testing and nonlinear finite element analysis (FEA) employing damage zone criterion for definition of failure. The results obtained from the second part of the investigation confirmed that the failure of the ductile lap shear brazed joints occurs when the damage zone reaches approximately 10% of the overlap width. The same failure criterion was applicable to the lap joints containing flaws.

  5. Arterial Stiffness and Pulse Wave Reflection Are Increased in Patients Suffering from Severe Periodontitis

    PubMed Central

    Jockel-Schneider, Yvonne; Harks, Inga; Haubitz, Imme; Fickl, Stefan; Eigenthaler, Martin; Schlagenhauf, Ulrich; Baulmann, Johannes

    2014-01-01

    Aim This single blind cross-sectional study compared the vascular health of subjects suffering from severe chronic periodontitis, severe aggressive periodontitis and periodontal healthy controls by evaluating pulse wave velocity (PWV), augmentation index (AIx) and pulse pressure amplification (PPA). Material and Methods In a total of 158 subjects, 92 suffering from severe periodontitis and 66 matched periodontal healthy controls, PWV, AIx, central and peripheral blood pressure were recorded using an oscillometric device (Arteriograph). Results Subjects suffering from severe chronic or aggressive periodontitis exhibited significantly higher PWV (p = 0.00004), higher AIx (p = 0.0049) and lower PPA (p = 0.028) than matched periodontal healthy controls. Conclusions The results of this study confirm the association between periodontal inflammation and increased cardiovascular risk shown by impaired vascular health in case of severe periodontitis. As impaired vascular health is a common finding in patients suffering from severe periodontal disease a concomitant routine cardiovascular evaluation may be advised. PMID:25084111

  6. Effects of periodontal therapy on white blood cell count and levels of transforming growth factor beta in serum of subjects with severe periodontitis.

    PubMed

    Leite, A C E; Carneiro, V M A; Morandini, A C; Ramos-Junior, E S; Guimarães, M C M

    2015-03-28

    This study aimed to investigate the effects of nonsurgical periodontal therapy on white blood cell (WBC) count and levels of transforming growth factor beta (TGF—β) in serum from subjects with severe periodontitis. Serum from 28 subjects with periodontitis (mean age: 34.36±6.24; 32% men) and 27 healthy controls (mean age: 33.18±6.42; 33% men) were collected prior to therapy. Blood samples were obtained from 23 subjects who completed therapy (9—12 months). A well—controlled periodontal treatment protocol was established in three stages: mechanical periodontal therapy (scaling and root planning), reinstrumentation of dental sites, and supportive periodontal therapy. Periodontal and systemic parameters such as the total number of WBCs and TGF—β levels, accessed by enzyme—linked immunosorbent assay (ELISA), were included. After therapy, all clinical periodontal parameters decreased (p<0.0001). There were no statistical differences in WBC count between experimental and control groups before or after therapy. However, after therapy, the mean value of lymphocytes in patients with localized aggressive periodontitis (LAgP) was statistically higher than that of patients with generalized chronic periodontitis (GCP) (p<0.0357). Additionally, TGF—β levels in LAgP and GCP patients were higher compared to controls before therapy (p<0.05 and p<0.01, respectively). In LAgP patients, periodontal therapy was associated with increased number of lymphocytes.

  7. Periodontal disease in children and adolescents of Latin America.

    PubMed

    Botero, Javier E; Rösing, Cassiano Kuchenbecker; Duque, Andres; Jaramillo, Adriana; Contreras, Adolfo

    2015-02-01

    Periodontal diseases are a group of infectious diseases that mainly include gingivitis and periodontitis. Gingivitis is the most prevalent form of periodontal disease in subjects of all ages, including children and adolescents. Less frequent types of periodontal disease include aggressive periodontitis, acute necrotizing ulcerative gingivitis and various diseases of herpesviral and fungal origin. This review aimed to retrieve relevant information from Latin America on the prevalence of periodontal diseases among children and adolescents of the region. Gingivitis was detected in 35% of young Latin American subjects and showed the highest frequencies in Colombia (77%) and Bolivia (73%) and the lowest frequency in Mexico (23%). The frequency of gingivitis in subjects from other Latin American countries was between 31% and 56%. Periodontitis may affect <10% of the young population in Latin America, but the data are based on only a few studies. A more precise assessment of the distribution and severity of periodontal disease in children and adolescents of Latin America may help policy makers and dentists to institute more effective public health measures to prevent and treat the disease at an early age to avoid major damage to the permanent dentition.

  8. Identification of biomarkers for periodontal disease using the immunoproteomics approach

    PubMed Central

    Kerishnan, Jesinda P.; Mohammad, Sani; Alias, Muhamad Shaifunizam; Mu, Alan Kang-Wai; Vaithilingam, Rathna Devi; Baharuddin, Nor Adinar; Safii, Syarida H.; Abdul Rahman, Zainal Ariff; Chen, Yu Nieng

    2016-01-01

    Background Periodontitis is one of the most common oral diseases associated with the host’s immune response against periodontopathogenic infection. Failure to accurately diagnose the stage of periodontitis has limited the ability to predict disease status. Therefore, we aimed to look for reliable diagnostic markers for detection or differentiation of early stage periodontitis using the immunoprotemic approach. Method In the present study, patient serum samples from four distinct stages of periodontitis (i.e., mild chronic, moderate chronic, severe chronic, and aggressive) and healthy controls were subjected to two-dimensional gel electrophoresis (2-DE), followed by silver staining. Notably, we consistently identified 14 protein clusters in the sera of patients and normal controls. Results Overall, we found that protein levels were comparable between patients and controls, with the exception of the clusters corresponding to A1AT, HP, IGKC and KNG1 (p < 0.05). In addition, the immunogenicity of these proteins was analysed via immunoblotting, which revealed differential profiles for periodontal disease and controls. For this reason, IgM obtained from severe chronic periodontitis (CP) sera could be employed as a suitable autoantibody for the detection of periodontitis. Discussion Taken together, the present study suggests that differentially expressed host immune response proteins could be used as potential biomarkers for screening periodontitis. Future studies exploring the diagnostic potential of such factors are warranted. PMID:27635317

  9. Periodontal disease associated to systemic genetic disorders.

    PubMed

    Nualart Grollmus, Zacy Carola; Morales Chávez, Mariana Carolina; Silvestre Donat, Francisco Javier

    2007-05-01

    A number of systemic disorders increase patient susceptibility to periodontal disease, which moreover evolves more rapidly and more aggressively. The underlying factors are mainly related to alterations in immune, endocrine and connective tissue status. These alterations are associated with different pathologies and syndromes that generate periodontal disease either as a primary manifestation or by aggravating a pre-existing condition attributable to local factors. This is where the role of bacterial plaque is subject to debate. In the presence of qualitative or quantitative cellular immune alterations, periodontal disease may manifest early on a severe localized or generalized basis--in some cases related to the presence of plaque and/or specific bacteria (severe congenital neutropenia or infantile genetic agranulocytosis, Chediak-Higiashi syndrome, Down syndrome and Papillon-Lefévre syndrome). In the presence of humoral immune alterations, periodontal damage may result indirectly as a consequence of alterations in other systems. In connective tissue disorders, bacterial plaque and alterations of the periodontal tissues increase patient susceptibility to gingival inflammation and alveolar resorption (Marfan syndrome and Ehler-Danlos syndrome). The management of periodontal disease focuses on the control of infection and bacterial plaque by means of mechanical and chemical methods. Periodontal surgery and even extraction of the most seriously affected teeth have also been suggested. There are variable degrees of consensus regarding the background systemic disorder, as in the case of Chediak-Higiashi syndrome, where antibiotic treatment proves ineffective; in severe congenital neutropenia or infantile genetic agranulocytosis, where antibiotic prophylaxis is suggested; and in Papillon-Lefévre syndrome, where an established treatment protocol is available.

  10. INTERIOR OF WEST SPAN LOOKING WEST (SHADOW OF VERTICAL LAPS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR OF WEST SPAN LOOKING WEST (SHADOW OF VERTICAL LAPS PLACED ON ZONE III; ASPHALT ZONE IX) - Honey Run Bridge, Spanning Butte Creek, bypassed section of Honey Run Road (originally Carr Hill Road), Paradise, Butte County, CA

  11. 15 CFR 285.5 - Termination of a LAP.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... OF STANDARDS AND TECHNOLOGY, DEPARTMENT OF COMMERCE ACCREDITATION AND ASSESSMENT PROGRAMS NATIONAL VOLUNTARY LABORATORY ACCREDITATION PROGRAM § 285.5 Termination of a LAP. (a) The Chief of NVLAP...

  12. Mechanical properties of a lap joint under uniform clamping pressure

    NASA Technical Reports Server (NTRS)

    Diller, S. V.; Metherell, A. F.

    1969-01-01

    Equations were derived for the load deflection relations, the energy dissipation per cycle, and the instantaneous rate of dissipation for a lap joint idealized as two overlapping plates clamped together under a uniform clamping pressure.

  13. FRICTION STIR LAP WELDING OF ALUMINUM - POLYMER USING SCRIBE TECHNOLOGY

    SciTech Connect

    Upadhyay, Piyush; Hovanski, Yuri; Fifield, Leonard S.; Simmons, Kevin L.

    2015-02-16

    Friction Stir Scribe (FSS) technology is a relatively new variant of Friction Stir Welding (FSW) which enables lap joining of dissimilar material with very different melting points and different high temperature flow behaviors. The cutter scribe attached at the tip of FSW tool pin effectively cuts the high melting point material such that a mechanically interlocking feature is created between the dissimilar materials. The geometric shape of this interlocking feature determines the shear strength attained by the lap joint. This work presents first use of scribe technology in joining polymers to aluminum alloy. Details of the several runs of scribe welding performed in lap joining of ~3.175mm thick polymers including HDPE, filled and unfilled Nylon 66 to 2mm thick AA5182 are presented. The effect of scribe geometry and length on weld interlocking features is presented along with lap shear strength evaluations.

  14. 13. Detail closeup view of wooden peg fastenings; note lapped ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. Detail close-up view of wooden peg fastenings; note lapped joint fastened with iron bolts using washers fashioned from oxen shoes. - Mormon Tabernacle, Temple Square, Salt Lake City, Salt Lake County, UT

  15. Adhesive-bonded scarf and stepped-lap joints

    NASA Technical Reports Server (NTRS)

    Hart-Smith, L. J.

    1973-01-01

    Continuum mechanics solutions are derived for the static load-carrying capacity of scarf and stepped-lap adhesive-bonded joints. The analyses account for adhesive plasticity and adherend stiffness imbalance and thermal mismatch. The scarf joint solutions include a simple algebraic formula which serves as a close lower bound, within a small fraction of a per cent of the true answer for most practical geometries and materials. Digital computer programs were developed and, for the stepped-lap joints, the critical adherend and adhesive stresses are computed for each step. The scarf joint solutions exhibit grossly different behavior from that for double-lap joints for long overlaps inasmuch as that the potential bond shear strength continues to increase with indefinitely long overlaps on the scarf joints. The stepped-lap joint solutions exhibit some characteristics of both the scarf and double-lap joints. The stepped-lap computer program handles arbitrary (different) step lengths and thickness and the solutions obtained have clarified potentially weak design details and the remedies. The program has been used effectively to optimize the joint proportions.

  16. Periodontal Disease Part IV: Periodontal Infections

    PubMed Central

    Turnbull, Robert S.

    1988-01-01

    In Part IV of this article, the author describes two periodontal infections, acute necrotizing ulcerative gingivitis (trench mouth) and periodontal abscess, both acute painful conditions for which patients may seek advice from their family physician rather than their dentist. PMID:21253201

  17. Regenerative periodontal therapy.

    PubMed

    Hägi, Tobias T; Laugisch, Oliver; Ivanovic, Aleksandar; Sculean, Anton

    2014-03-01

    The goal of regenerative periodontal therapy is to completely restore the tooth's supporting apparatus that has been lost due to inflammatory periodontal disease or injury. It is characterized by formation of new cementum with inserting collagen fibers, new periodontal ligament, and new alveolar bone. Indeed conventional, nonsurgical, and surgical periodontal therapy usually result in clinical improvements evidenced by probing depth reduction and clinical attachment gain, but the healing occurs predominantly through formation of a long junctional epithelium and no or only unpredictable periodontal regeneration. Therefore, there is an ongoing search for new materials and improved surgical techniques, with the aim of predictably promoting periodontal wound healing/regeneration and improving the clinical outcome. This article attempts to provide the clinician with an overview of the most important biologic events involved in periodontal wound healing/ regeneration and on the criteria on how to select the appropriate regenerative material and surgical technique in order to optimize the clinical outcomes.

  18. Flaw Tolerance in Lap Shear Brazed Joints. Part 1

    NASA Technical Reports Server (NTRS)

    Flom, Yury; Wang, Li-Qin

    2003-01-01

    Furnace brazing is a joining process used in the aerospace and other industries to produce strong permanent and hermetic structural joints. As in any joining process, brazed joints have various imperfections and defects. At the present time, our understanding of the influence of the internal defects on the strength of the brazed joints is not adequate. The goal of this 3-part investigation is to better understand the properties and failure mechanisms of the brazed joints containing defects. This study focuses on the behavior of the brazed lap shear joints because of their importance in manufacturing aerospace structures. In Part 1, an average shear strength capability and failure modes of the single lap joints are explored. Stainless steel specimens brazed with pure silver are tested in accordance with the AWS C3.2 standard. Comparison of the failure loads and the ultimate shear strength with the Finite Element Analysis (FEA) of the same specimens as a function of the overlap widths shows excellent correlation between the experimental and calculated values for the defect-free lap joints. A damage zone criterion is shown to work quite well in understanding the failure of the braze joints. In Part 2, the findings of the Part 1 will be verified on the larger test specimens. Also, various flaws will be introduced in the test specimens to simulate lack of braze coverage in the lap joints. Mechanical testing and FEA will be performed on these joints to verify that behavior of the flawed ductile lap joints is similar to joints with a reduced braze area. Finally, in Part 3, the results obtained in Parts 1 and 2 will be applied to the actual brazed structure to evaluate the load-carrying capability of a structural lap joint containing discontinuities. In addition, a simplified engineering procedure will be offered for the laboratory testing of the lap shear specimens.

  19. Use of two-dimensional transmission photoelastic models to study stresses in double-lap bolted joints: Load transfer and stresses in the inner lap

    NASA Technical Reports Server (NTRS)

    Hyer, M. W.

    1980-01-01

    The determination of the stress distribution in the inner lap of double-lap, double-bolt joints using photoelastic models of the joint is discussed. The principal idea is to fabricate the inner lap of a photoelastic material and to use a photoelastically sensitive material for the two outer laps. With this setup, polarized light transmitted through the stressed model responds principally to the stressed inner lap. The model geometry, the procedures for making and testing the model, and test results are described.

  20. LAP5 and LAP6 Encode Anther-Specific Proteins with Similarity to Chalcone Synthase Essential for Pollen Exine Development in Arabidopsis1[W][OA

    PubMed Central

    Dobritsa, Anna A.; Lei, Zhentian; Nishikawa, Shuh-ichi; Urbanczyk-Wochniak, Ewa; Huhman, David V.; Preuss, Daphne; Sumner, Lloyd W.

    2010-01-01

    Pollen grains of land plants have evolved remarkably strong outer walls referred to as exine that protect pollen and interact with female stigma cells. Exine is composed of sporopollenin, and while the composition and synthesis of this biopolymer are not well understood, both fatty acids and phenolics are likely components. Here, we describe mutations in the Arabidopsis (Arabidopsis thaliana) LESS ADHESIVE POLLEN (LAP5) and LAP6 that affect exine development. Mutation of either gene results in abnormal exine patterning, whereas pollen of double mutants lacked exine deposition and subsequently collapsed, causing male sterility. LAP5 and LAP6 encode anther-specific proteins with homology to chalcone synthase, a key flavonoid biosynthesis enzyme. lap5 and lap6 mutations reduced the accumulation of flavonoid precursors and flavonoids in developing anthers, suggesting a role in the synthesis of phenolic constituents of sporopollenin. Our in vitro functional analysis of LAP5 and LAP6 using 4-coumaroyl-coenzyme A yielded bis-noryangonin (a commonly reported derailment product of chalcone synthase), while similar in vitro analyses using fatty acyl-coenzyme A as the substrate yielded medium-chain alkyl pyrones. Thus, in vitro assays indicate that LAP5 and LAP6 are multifunctional enzymes and may play a role in both the synthesis of pollen fatty acids and phenolics found in exine. Finally, the genetic interaction between LAP5 and an anther gene involved in fatty acid hydroxylation (CYP703A2) demonstrated that they act synergistically in exine production. PMID:20442277

  1. Flaw Tolerance in Lap Shear Brazed Joints. Part 1

    NASA Technical Reports Server (NTRS)

    Flom, Yury; Wang, Liqin; Obenschain, Arthur F. (Technical Monitor)

    2002-01-01

    Vacuum brazing is a viable process to achieve strong permanent and hermetic joints in space. As in any joining process, brazed Joints have various imperfections and defects. It is important to understand the impact that flaws have on the load carrying capacity and performance of the brazed joints. This study focuses on the behavior of lap shear joints due to their engineering importance in brazed aerospace structures. In Part 1 an average shear strength capabilitY and failure modes of the single lap joints are explored. Specimens comprised of 0.090 inch thick 347 stainless steel sheet brazed with pure silver are tested in accordance with the AWS C3.2 standard. Comparison of the measured loads and average shear stresses at failure with the Finite Element Analysis (FEA) of the same specimens as a function of the overlap lengths shows excellent correlation between the experimental and calculated values for the defect-free lap joints. In Part 2, various flaws will be introduced in the test specimens to simulate lack of braze coverage in the lap joints. Mechanical testing and FEA will be performed on these joints to verify if behavior of ductile ]appoints containing flaws is similar to the joints with the reduced braze area. Finally, in Part 3, the results obtained in Part 1 and 2 will be applied to the brazed assembly to evaluate a load carrying capability of the structural lap joint containing defects.

  2. Ozone therapy in periodontics.

    PubMed

    Gupta, G; Mansi, B

    2012-02-22

    Gingival and Periodontal diseases represent a major concern both in dentistry and medicine. The majority of the contributing factors and causes in the etiology of these diseases are reduced or treated with ozone in all its application forms (gas, water, oil). The beneficial biological effects of ozone, its anti-microbial activity, oxidation of bio-molecules precursors and microbial toxins implicated in periodontal diseases and its healing and tissue regeneration properties, make the use of ozone well indicated in all stages of gingival and periodontal diseases. The primary objective of this article is to provide a general review about the clinical applications of ozone in periodontics. The secondary objective is to summarize the available in vitro and in vivo studies in Periodontics in which ozone has been used. This objective would be of importance to future researchers in terms of what has been tried and what the potentials are for the clinical application of ozone in Periodontics.

  3. Ozone therapy in periodontics

    PubMed Central

    Gupta, G; Mansi, B

    2012-01-01

    Gingival and Periodontal diseases represent a major concern both in dentistry and medicine. The majority of the contributing factors and causes in the etiology of these diseases are reduced or treated with ozone in all its application forms (gas, water, oil). The beneficial biological effects of ozone, its anti-microbial activity, oxidation of bio-molecules precursors and microbial toxins implicated in periodontal diseases and its healing and tissue regeneration properties, make the use of ozone well indicated in all stages of gingival and periodontal diseases. The primary objective of this article is to provide a general review about the clinical applications of ozone in periodontics. The secondary objective is to summarize the available in vitro and in vivo studies in Periodontics in which ozone has been used. This objective would be of importance to future researchers in terms of what has been tried and what the potentials are for the clinical application of ozone in Periodontics. PMID:22574088

  4. Lap time optimisation of a racing go-kart

    NASA Astrophysics Data System (ADS)

    Lot, Roberto; Dal Bianco, Nicola

    2016-02-01

    The minimum lap time optimal control problem has been solved for a go-kart model. The symbolic algebra software Maple has been used to derive equations of motion and an indirect method has been adopted to solve the optimal control problem. Simulation has been successfully performed on a full track lap with a multibody model endowed with seven degrees of freedom. Geometrical and mechanical characteristics of a real kart have been measured by a lab test to feed the mathematical model. Telemetry recorded in an entire lap by a professional driver has been compared to simulation results in order to validate the model. After the reliability of the optimal control model was proved, the simulation has been used to study the peculiar dynamics of go-karts and focus to tyre slippage dynamics, which is highly affected by the lack of differential.

  5. Loose abrasive lapping hardness of optical glasses and its interpretation.

    PubMed

    Lambropoulos, J C; Xu, S; Fang, T

    1997-03-01

    We present an interpretation of the lapping hardness of commercially available optical glasses in terms of a micromechanics model of material removal by subsurface lateral cracking. We analyze data on loose abrasive microgrinding, or lapping at fixed nominal pressure, for many commercially available optical glasses in terms of this model. The Schott and Hoya data on lapping hardness are correlated with the results of such a model. Lapping hardness is a function of the mechanical properties of the glass: The volume removal rate increases approximately linearly with Young's modulus, and it decreases with fracture toughness and (approximately) the square of the Knoop hardness. The microroughness induced by lapping depends on the plastic and elastic properties of the glass, depending on abrasive shape. This is in contrast to deterministic microgrinding (fixed infeed rate), where it is determined from the plastic and fracture properties of the glass. We also show that Preston's coefficient has a similar dependence as lapping hardness on glass mechanical properties, as well as a linear dependence on abrasive size for the case of brittle material removal. These observations lead to the definition of an augmented Preston coefficient during brittle material removal. The augmented Preston coefficient does not depend on glass material properties or abrasive size and thus describes the interaction of the glass surface with the coolant-immersed abrasive grain and the backing plate. Numerical simulations of indentation are used to locate the origin of subsurface cracks and the distribution of residual surface and subsurface stresses, known to cause surface (radial) and subsurface (median, lateral) cracks.

  6. Periodontal disease and diabetes.

    PubMed

    Bascones-Martínez, Antonio; Arias-Herrera, Santiago; Criado-Cámara, Elena; Bascones-Ilundáin, Jaime; Bascones-Ilundáin, Cristina

    2012-01-01

    Diabetes is considered to be a genetically and environmentally based chronic metabolic and vascular syndrome caused by a partial or total insulin deficiency with alteration in the metabolism of lipids, carbohydrates and proteins culminating with different manifestations in different organisms. In humans hyperglycemia is the main consequence of defects in the secretion and/or action of insulin, and its deregulation can produce secondary lesions in various organs, especially kidneys, eyes, nerves, blood vessels and immune systems. Periodontal disease is an entity of localized infection that involves tooth-supporting tissues. The first clinical manifestation of periodontal disease is the appearance of periodontal pockets, which offer a favorable niche for bacterial colonization. The etiology of periodontal disease is multifactorial, being caused by interactions between multiple micro-organisms (necessary but not sufficient primary etiologic factors), a host with some degree of susceptibility and environmental factors. According to current scientific evidence, there is a symbiotic relationship between diabetes and periodontitis, such that diabetes is associated with an increased incidence and progression of periodontitis, and periodontal infection is associated with poor glycaemic control in diabetes due to poor immune systems. Hence, for a good periodontal control it is necessary to treat both periodontal disease and glycaemic control.

  7. Systemic antibiotics in periodontics.

    PubMed

    Slots, Jørgen

    2004-11-01

    This position paper addresses the role of systemic antibiotics in the treatment of periodontal disease. Topical antibiotic therapy is not discussed here. The paper was prepared by the Research, Science and Therapy Committee of the American Academy of Periodontology. The document consists of three sections: 1) concept of antibiotic periodontal therapy; 2) efficacy of antibiotic periodontal therapy; and 3) practical aspects of antibiotic periodontal therapy. The conclusions drawn in this paper represent the position of the American Academy of Periodontology and are intended for the information of the dental profession.

  8. Periodontal considerations for children.

    PubMed

    Song, H Jung

    2013-01-01

    This article reviews periodontal disease and gingival disease and also explores issues relating to mucogingival defects such as gingival hyperplasia, gingival recession, and exposure of impacted canines.

  9. Seam-Tracking for Friction Stir Welded Lap Joints

    NASA Astrophysics Data System (ADS)

    Fleming, Paul A.; Hendricks, Christopher E.; Cook, George E.; Wilkes, D. M.; Strauss, Alvin M.; Lammlein, David H.

    2010-11-01

    This article presents a method for automatic seam-tracking in friction stir welding (FSW) of lap joints. In this method, tracking is accomplished by weaving the FSW tool back-and-forth perpendicular to the direction of travel during welding and monitoring force and torque signals. Research demonstrates the ability of this method to automatically track weld seam positions. Additionally, tensile and S-bend test result comparisons demonstrate that weaving most likely does not reduce weld quality. Finally, benefits of this weave-based method to FSW of lap joints are discussed and methods for incorporating it into existing friction stir welding control algorithms (such as axial load control) are examined.

  10. 15 CFR 285.4 - Establishment of laboratory accreditation programs (LAPs) within NVLAP.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... ACCREDITATION AND ASSESSMENT PROGRAMS NATIONAL VOLUNTARY LABORATORY ACCREDITATION PROGRAM § 285.4 Establishment of laboratory accreditation programs (LAPs) within NVLAP. NVLAP establishes LAPs in response to... accreditation programs (LAPs) within NVLAP. 285.4 Section 285.4 Commerce and Foreign Trade Regulations...

  11. Auto Mechanics I. Learning Activity Packets (LAPs). Section D--Suspension.

    ERIC Educational Resources Information Center

    Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains six learning activity packets (LAPs) that outline the study activities for the "suspension" instructional area for an Auto Mechanics I course. The six LAPs cover the following topics: wheel bearings, tires and wheels, wheel balancing, suspension system, steering system, and wheel alignment. Each LAP contains a…

  12. Auto Mechanics I. Learning Activity Packets (LAPs). Section C--Engine.

    ERIC Educational Resources Information Center

    Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains five learning activity packets (LAPs) that outline the study activities for the "engine" instructional area for an Auto Mechanics I course. The five LAPs cover the following topics: basic engine principles, cooling system, engine lubrication system, exhaust system, and fuel system. Each LAP contains a cover sheet…

  13. Long-term effect on tooth vitality of regenerative therapy in deep periodontal bony defects: a retrospective study.

    PubMed

    de Sanctis, Massimo; Goracci, Cecilia; Zucchelli, Giovanni

    2013-01-01

    Over the last few decades, many authors have investigated the effect of periodontal disease and treatment on pulpal status with controversial results. This study was conducted to verify whether periodontal disease in a deep intrabony defect and complex therapy, including aggressive root planing such as in periodontal regeneration, have an influence on tooth vitality. One hundred thirty-seven patients who fulfilled the requirements were included. The collected data did not support the need for "preventive" root canal treatment in severely compromised teeth that are planned to undergo periodontal regenerative surgery.

  14. Defining periodontal health

    PubMed Central

    2015-01-01

    Assessment of the periodontium has relied exclusively on a variety of physical measurements (e.g., attachment level, probing depth, bone loss, mobility, recession, degree of inflammation, etc.) in relation to various case definitions of periodontal disease. Periodontal health was often an afterthought and was simply defined as the absence of the signs and symptoms of a periodontal disease. Accordingly, these strict and sometimes disparate definitions of periodontal disease have resulted in an idealistic requirement of a pristine periodontium for periodontal health, which makes us all diseased in one way or another. Furthermore, the consequence of not having a realistic definition of health has resulted in potentially questionable recommendations. The aim of this manuscript was to assess the biological, environmental, sociological, economic, educational and psychological relationships that are germane to constructing a paradigm that defines periodontal health using a modified wellness model. The paradigm includes four cardinal characteristics, i.e., 1) a functional dentition, 2) the painless function of a dentition, 3) the stability of the periodontal attachment apparatus, and 4) the psychological and social well-being of the individual. Finally, strategies and policies that advocate periodontal health were appraised. I'm not sick but I'm not well, and it's a sin to live so well. Flagpole Sitta, Harvey Danger PMID:26390888

  15. Integrins in periodontal disease.

    PubMed

    Larjava, Hannu; Koivisto, Leeni; Heino, Jyrki; Häkkinen, Lari

    2014-07-15

    Cell surface integrin receptors mediate cell adhesion, migration and cellular signaling in all nucleated cells. They are activated by binding to extracellular ligands or by intracellular proteins, such as kindlins that engage with their cytoplasmic tails. Cells in the periodontal tissues express several integrins with overlapping ligand-binding capabilities. A distinct phenotype in the periodontium has only been described for knockouts or mutations of three integrin subunits, α11, β6 and β2. Integrin α11β1 appears to have some regulatory function in the periodontal ligament of continuously erupting incisors in mice. Integrin αvβ6 is expressed in the junctional epithelium (JE) of the gingiva. Animals deficient in this receptor develop classical signs of periodontal disease, including inflammation, apical migration of the JE and bone loss, suggesting that it plays a role in the regulation of periodontal inflmmation, likely through activation of transforming growth factor-β1. Lack of integrin activation in the JE is also associated with periodontitis. Patients with kindlin-1 mutations have severe early-onset periodontal disease. Finally, patients with mutations in the leukocyte-specific β2 integrin subunit have severe periodontal problems due to lack of transiting neutrophils in the periodontal tissues.

  16. Periodontitis and myocardial hypertrophy.

    PubMed

    Suzuki, Jun-Ichi; Sato, Hiroki; Kaneko, Makoto; Yoshida, Asuka; Aoyama, Norio; Akimoto, Shouta; Wakayama, Kouji; Kumagai, Hidetoshi; Ikeda, Yuichi; Akazawa, Hiroshi; Izumi, Yuichi; Isobe, Mitsuaki; Komuro, Issei

    2017-04-01

    There is a deep relationship between cardiovascular disease and periodontitis. It has been reported that myocardial hypertrophy may be affected by periodontitis in clinical settings. Although these clinical observations had some study limitations, they strongly suggest a direct association between severity of periodontitis and left ventricular hypertrophy. However, the detailed mechanisms between myocardial hypertrophy and periodontitis have not yet been elucidated. Recently, we demonstrated that periodontal bacteria infection is closely related to myocardial hypertrophy. In murine transverse aortic constriction models, a periodontal pathogen, Aggregatibacter actinomycetemcomitans markedly enhanced cardiac hypertrophy with matrix metalloproteinase-2 activation, while another pathogen Porphyromonas gingivalis (P.g.) did not accelerate these pathological changes. In the isoproterenol-induced myocardial hypertrophy model, P.g. induced myocardial hypertrophy through Toll-like receptor-2 signaling. From our results and other reports, regulation of chronic inflammation induced by periodontitis may have a key role in the treatment of myocardial hypertrophy. In this article, we review the pathophysiological mechanism between myocardial hypertrophy and periodontitis.

  17. Highly Porous and Compositionally Intermediate Ordinary Chondrite LAP 031047

    NASA Astrophysics Data System (ADS)

    Wittmann, A.; Kring, D. A.; Friedrich, J. M.; Troiano, J.; Macke, R. J.; Britt, D. T.; Swindle, T. D.; Weirich, J. R.; Rumble, D.

    2010-03-01

    LAP 031047 is a highly porous ordinary chondrite with a very young Ar-Ar age, and oxygen isotopic, and bulk and silicate mineral composition intermediate between H- and L-chondrites: Shock-lithified debris of a distinct ordinary chondrite asteroid?

  18. Learning Activity Package, Physical Science 92, LAPs 1-9.

    ERIC Educational Resources Information Center

    Williams, G. J.

    This set of nine teacher-prepared Learning Activity Packages (LAPs) for individualized instruction in physical science covers the topics of scientific equipment and procedures; measure of time, length, area, and volume; water; oxygen and oxidation; atmospheric pressure; motion; machines; carbon; and light and sound. Each unit contains a rationale…

  19. Learning Activity Package, Algebra 124, LAPs 46-55.

    ERIC Educational Resources Information Center

    Holland, Bill

    A series of 10 teacher-prepared Learning Activity Packages (LAPs) in advanced algebra and trigonometry, these units cover absolute value, inequalities, exponents, radicals, and complex numbers; functions; higher degree equations and the derivative; the trigonometric functions; graphs and applications of the trigonometric functions; sequences and…

  20. Insights: A LAP on Moles: Teaching an Important Concept.

    ERIC Educational Resources Information Center

    Ihde, John

    1985-01-01

    Describes a learning activity packet (LAP) designed to help students understand the basic concept of the mole as a chemical unit; know relationships between the mole and atomic weights in the periodic table; and solve basic conversion problems involving moles, atoms, and molecules. (JN)

  1. Occlusal trauma--periodontal concerns.

    PubMed

    Hallmon, W W

    2001-10-01

    While there is evidence that suggests that occlusal trauma is a risk factor for periodontal destruction, there is no evidence that indicates that occlusal trauma will initiate periodontal destruction. Effective plaque control and compliance with periodontal maintenance recommendations are key and essential factors necessary to assure successful treatment and control of periodontal disease.

  2. An Ultrasonographic Periodontal Probe

    NASA Astrophysics Data System (ADS)

    Bertoncini, C. A.; Hinders, M. K.

    2010-02-01

    Periodontal disease, commonly known as gum disease, affects millions of people. The current method of detecting periodontal pocket depth is painful, invasive, and inaccurate. As an alternative to manual probing, an ultrasonographic periodontal probe is being developed to use ultrasound echo waveforms to measure periodontal pocket depth, which is the main measure of periodontal disease. Wavelet transforms and pattern classification techniques are implemented in artificial intelligence routines that can automatically detect pocket depth. The main pattern classification technique used here, called a binary classification algorithm, compares test objects with only two possible pocket depth measurements at a time and relies on dimensionality reduction for the final determination. This method correctly identifies up to 90% of the ultrasonographic probe measurements within the manual probe's tolerance.

  3. Dynamic deformation measurement and analysis of active stressed lap using optical method

    NASA Astrophysics Data System (ADS)

    Zhang, Qican; Su, Xianyu; Liu, Yuankun; Xiang, Liqun

    2007-12-01

    The active stressed lap is the heart of polishing process. A novel non-contact optical method of dynamic deformation measurement and analysis of an active stressed lap is put forward. This method, based on structured illumination, is able to record full-field information of the bending and rotating stressed lap dynamically and continuously, while its profile is changed under computer control, and restore the whole process of lap deformation varied with time at different position and rotating angle. It has been verified by experiments that this proposed method will be helpful to the opticians to ensure the stressed lap as expected.

  4. [Orthodontic treatment in periodontal patients].

    PubMed

    Krausz, E; Einy, S; Aizenbud, D; Levin, L

    2011-07-01

    Orthodontic treatment poses a significant challenge in patients suffering from periodontal disease. Providing orthodontic treatment to periodontal patients should be carefully planned and performed in a tight collaboration between the orthodontist and periodontist. Resolution and stabilization of the periodontal condition is a pre-requisite for orthodontic treatment initiation. Careful oral hygiene performance and highly frequent recall periodontal visits are also crucial. Pre- or post- orthodontic periodontal surgery might help providing better treatment outcomes.

  5. Consensus training: an effective tool to minimize variations in periodontal diagnosis and treatment planning among dental faculty and students.

    PubMed

    John, Vanchit; Lee, Seung-Jun; Prakasam, Sivaraman; Eckert, George J; Maupome, Gerardo

    2013-08-01

    Considerable disagreements and variations exist in diagnosis and treatment planning of periodontal disease. Achieving high interrater periodontal diagnosis can prove challenging. The objectives of this study were to measure variations in periodontal diagnosis and treatment planning among predoctoral periodontics faculty members after consensus training and to compare such variation with those identified in third- and fourth-year dental students. Nine electronically stored case vignettes and survey instruments were made available to eighteen faculty members and twenty dental students under standardized conditions. A chi-square test was used to compare responses between groups, and multirater kappa tests were used to evaluate interrater agreement/reliability. Of the nine cases, only one differed between groups significantly in terms of treatment. Also, third-year students differed from fourth-year students on the diagnosis of aggressive periodontitis versus chronic periodontitis. Most respondents were able to distinguish clearly among diagnoses of chronic periodontitis, aggressive periodontitis, and gingivitis. This study established a baseline assessment of the current status of consensus after training. We will reassess variations after addressing the specific challenges identified. Programs designed and implemented to help decrease the variation in periodontal diagnosis and treatment planning among faculty members may ultimately translate into better agreement and better standardization of dental instruction.

  6. The Immediate Aesthetic and Functional Restoration of Maxillary Incisors Compromised by Periodontitis Using Short Implants with Single Crown Restorations: A Minimally Invasive Approach and Five-Year Follow-Up

    PubMed Central

    Marincola, Mauro; Lombardo, Giorgio; Pighi, Jacopo; Corrocher, Giovanni; Mascellaro, Anna; Lehrberg, Jeffrey; Nocini, Pier Francesco

    2015-01-01

    The functional and aesthetic restoration of teeth compromised due to aggressive periodontitis presents numerous challenges for the clinician. Horizontal bone loss and soft tissue destruction resulting from periodontitis can impede implant placement and the regeneration of an aesthetically pleasing gingival smile line, often requiring bone augmentation and mucogingival surgery, respectively. Conservative approaches to the treatment of aggressive periodontitis (i.e., treatments that use minimally invasive tools and techniques) have been purported to yield positive outcomes. Here, we report on the treatment and five-year follow-up of patient suffering from aggressive periodontitis using a minimally invasive surgical technique and implant system. By using the methods described herein, we were able to achieve the immediate aesthetic and functional restoration of the maxillary incisors in a case that would otherwise require bone augmentation and extensive mucogingival surgery. This technique represents a conservative and efficacious alternative to the aesthetic and functional replacement of teeth compromised due to aggressive periodontitis. PMID:26649207

  7. Periodontal diseases: microbiological considerations.

    PubMed

    Liébana, José; Castillo, Ana María; Alvarez, Marta

    2004-01-01

    The location of plaque-associated gingivitis at the gingival portion of the tooth plays an essential role in its genesis. However, at times local and other host response modifying factors also have an influence. The pathogeny of periodontitis is more complex. The microorganisms that comprise subgingival plaque are capable of acting directly on periodontal tissues or of modifying the host response, whereas the participation of the plaque per se (normal, decreased, or increased) is as decisive as the action of the bacteria themselves in the emergence of the disease. Different types of periodontitis are associated with specific microorganisms. The most periodontopathogenic are A. actinomycetemcomitans, P. gingivalis, and T. forsythensis. Periodontitis as a whole, represent the source of complications such as root caries, endoperiodontal processes and periodontal abscesses. They are associated with various illnesses such as atherosclerosis, diabetes, and respiratory infections, amongst others, as well as pathological oral halitosis. The different modalities of PCR are particularly important in the microbiological diagnosis of periodontitis, although on the negative side of things, it must be pointed out that in vitro sensitivity studies cannot be performed using this technique. First line antibiotic treatment of periodontitis includes amoxicillin/ clavulanic acid, metronidazole (associated or not with amoxicillin) and clindamycin.

  8. [Nutrition and periodontal disease].

    PubMed

    Indrei, L L

    2006-01-01

    It is difficult ro assess the role of nutrition in the etiology and progression of periodontal disease because many other factors besides the local effect of plaque affect periodontal tissue metabolism. It is clear that nutrition can affect host response to bacterial plaque and it is also apparent that there may be a need for the intake of greater amounts of certain nutrients (such as ascorbic acid, iron etc.). Inadequate nutrient intake or deficiency is significant because of the number of interactions that occur during the assimilation of foods and the effects of stress and medication. Periodontal health cannot be achieved unless nutrient deficiency is corrected along with the other phases of treatment.

  9. Detection of Periodontal Markers in Chronic Periodontitis

    PubMed Central

    Leonhardt, Åsa; Carlén, Anette; Bengtsson, Lisbeth; Dahlén, Gunnar

    2011-01-01

    The aim was to compare the detection frequency of periodontopathogens by using the Pado Test 4.5 and checkerboard DNA-DNA hybridization technique in chronic periodontitis patients. Thirty patients with chronic periodontitis were tested cross-sectionally with DNA/RNA oligogenomic probe method (IAI Pado Test 4.5) and DNA/DNA whole genomic probe (checkerboard) method. Samples were taken by two paper points at the deepest site in each of the four quadrants and pooled into one sample for each of the two methods. The samples were sent to the two laboratories (IAI, Zuchwil, Switzerland, and Oral Microbiology Laboratory, University of Gothenburg, Sweden) and were analyzed in a routine setting for the presence and amount of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola. While Pado Test 4.5 detected the four periodontal pathogens in 11 (36.7%) of the patients, the checkerboard method showed presence in all patients (100%) using the lower score (Score 1 corresponding to 104 bacterial cells) and 16 (53.3%) using a higher treshold (score 3 corresponding to between >105 and 106 cells). The results of the present study showed low agreement for a positive microbiological outcome using the two diagnostic methods. It was also concluded that microbiological analysis in practice should include a larger number of bacterial species to better serve as markers for a diseased associated flora in chronic periodontitis cases. PMID:21769304

  10. Inflammatory Myofibroblastic Tumor Mimicking Apical Periodontitis.

    PubMed

    Adachi, Makoto; Kiho, Kazuki; Sekine, Genta; Ohta, Takahisa; Matsubara, Makoto; Yoshida, Takakazu; Katsumata, Akitoshi; Tanuma, Jun-ichi; Sumitomo, Shinichiro

    2015-12-01

    Inflammatory myofibroblastic tumors (IMTs) are rare. IMTs of the head and neck occur in all age groups, from neonates to old age, with the highest incidence occurring in childhood and early adulthood. An IMT has been defined as a histologically distinctive lesion of uncertain behavior. This article describes an unusual case of IMT mimicking apical periodontitis in the mandible of a 42-year-old man. At first presentation, the patient showed spontaneous pain and percussion pain at teeth #28 to 30, which continued after initial endodontic treatment. Panoramic radiography revealed a radiolucent lesion at the site. Cone-beam computed tomographic imaging showed osteolytic lesions, suggesting an aggressive neoplasm requiring incisional biopsy. Histopathological examination indicated an IMT. The lesion was removed en bloc under general anesthesia, and the patient manifested no clinical evidence of recurrence for 24 months. Lesions of nonendodontic origin should be included in the differential diagnosis of apical periodontitis. Every available diagnostic tool should be used to confirm the diagnosis. Cone-beam computed tomographic imaging is very helpful for differential diagnosis in IMTs mimicking apical periodontitis.

  11. Material characterization of structural adhesives in the lap shear mode

    NASA Technical Reports Server (NTRS)

    Sancaktar, E.; Schenck, S. C.

    1983-01-01

    A general method for characterizing structual adhesives in the bonded lap shear mode is proposed. Two approaches in the form of semiempirical and theoretical approaches are used. The semiempirical approach includes Ludwik's and Zhurkov's equations to describe respectively, the failure stresses in the constant strain rate and constant stress loading modes with the inclusion of the temperature effects. The theoretical approach is used to describe adhesive shear stress-strain behavior with the use of viscoelastic or nonlinear elastic constitutive equations. Two different model adhesives are used in the single lap shear mode with titanium adherends. These adhesives (one of which was developed at NASA Langley Research Center) are currently considered by NASA for possible aerospace applications. Use of different model adhesives helps in assessment of the generality of the method.

  12. Analytical and experimental investigation of fatigue in lap joints

    NASA Astrophysics Data System (ADS)

    Swenson, Daniel V.; Chih-Chien, Chia; Derber, Thomas G.

    A finite element model is presented that can simulate crack growth in layered structures such as lap joints. The layers can be joined either by rivets or adhesives. The crack is represented discretely in the mesh, and automatic remeshing is performed as the crack grows. Because of the connections between the layers, load is transferred to the uncracked layer as the crack grows. This reduces the stress intensity and slows the crack growth rate. The model is used to analyze tests performed on a section of a wing spanwise lap joint. The crack was initiated at a rivet and grown under constant amplitude cyclic loads. Both experimentally observed crack growth rates and the analysis show the retardation that occurs as a result of load transfer between layers. A good correlation is obtained between predicted and observed crack growth rates for the fullly developed through-thickness crack.

  13. FRICTION-STIR-LAP-WELDS OF AA6111 ALUMINUM ALLOY

    SciTech Connect

    Yadava, Manasij; Mishra, Rajiv S.; Chen, Y. L.; Gayden, X.; Grant, Glenn J.

    2007-01-09

    Lap joints of 1 mm thick AA6111 aluminum sheets were made by friction stir welding, using robotic and conventional machines. Welds were made for advancing as well as retreating side loading. Thinning in welds was quantified. Lap shear test of welds was conducted in as-welded and paint-baked conditions. Conventional machine welds showed less thinning and better strength than robotic machine welds. Process forces in conventional machine welding were higher. Paint bake treatment improved the weld strength; but the improvement varied with process parameters. Advancing side loaded welds achieved higher strength than the retreating side loaded welds. Fracture location was found to occur on the loaded side of the weld and along the thinning defect.

  14. Periodontitis and osteoporosis.

    PubMed

    Straka, Michal; Straka-Trapezanlidis, Michaela; Deglovic, Juraj; Varga, Ivan

    2015-01-01

    Today's knowledge and studies show a firm correlation between osteoporosis and periodontitis, particularly in postmenopausal women. This review study deals with epidemiological and etiopathogenetic association between chronic periodontitis and an osteoporosis. A special emphasis is put on explanation of possible relations between a premature tooth loss and decrease of length and density of jaw bones, particularly their alveolar prolongations. The second part of the paper deals with principles of treatment in patients suffering of osteoporosis. Osteoporosis reduces density of jaw bones and decreases a number of teeth in jaws, but it does not affect other clinical signs and markers of periodontitis such as inflammation, bleeding and the depth of periodontal pockets and microbial plaque.

  15. Chronic Mammalian Toxicological Effects of LAP (Load, Assemble, and Pack).

    DTIC Science & Technology

    1980-09-01

    samples were extracted and cleaned up according to official AOAC methods .- The extracts were analyzed for chlorinated organic *; pesticides using glass...Weight Variation From Control Males . . .... 54 4. Percent Body Weight Variation From Control Females .. ...... 55 . 6 *%1% 6? LIST OF TABLES 1. Pesticides...corn oil with acetone added and removed in the same manner as for the LAP samples. Stability studies using this method showed that diets mixed once every

  16. Pharmacology of Periodontal Disease.

    DTIC Science & Technology

    2014-09-26

    k 7RD-A157 116 PHARMRCOLOGY’ OF PERIODONTAL DISEASE(U) UNIVERSITY OF i/ I HEALTH SCIENCES/CHICAGO MEDICAL SCHOOL DEPT OF I PHARMACOLOGY S F HOFF 24...University of Health Sciences/The Chicago Medical School Department of 3333 Green Bay Road Telephone Pharmacology North Chicago, Illinois 60064...Region Bethesda, MD 20814-5044 • .RE: Annual Letter Report , ONR Contract #N00014-84-K-0562 " Pharmacology of Periodontal Disease" Dear Capt. Hancock

  17. Physiological features of periodontal regeneration and approaches for periodontal tissue engineering utilizing periodontal ligament cells.

    PubMed

    Benatti, Bruno Braga; Silvério, Karina Gonzales; Casati, Márcio Zaffalon; Sallum, Enílson Antônio; Nociti, Francisco Humberto

    2007-01-01

    Experimental studies have shown that the potential of periodontal regeneration seems to be limited by the regenerative capacity of the cells involved. The regeneration of damaged periodontal tissues is mediated by various periodontal cells and is regulated by a vast array of extracellular matrix informational molecules that induce both selective and nonselective responses in different cell lineages and their precursors. In this paper, we first review periodontal ligament tissue and its different cell subpopulations including fibroblasts and paravascular stem cells, and their functions during the development and homeostasis of periodontal tissues. Because conventional periodontal regeneration methods remain insufficient to obtain a complete and reliable periodontal regeneration, the concept of periodontal tissue engineering has been based on the generation of the conditions necessary to improve the healing of periodontal tissues. Additionally, the potential of periodontal ligament cells for use in periodontal tissue engineering to overcome the limitations of conventional periodontal regenerative therapies is discussed, followed by an update of the recent progress and future directions of research utilizing periodontal ligament cells for predictable periodontal regeneration.

  18. Nonlinear Analysis of Bonded Composite Tubular Lap Joints

    NASA Technical Reports Server (NTRS)

    Oterkus, E.; Madenci, E.; Smeltzer, S. S., III; Ambur, D. R.

    2005-01-01

    The present study describes a semi-analytical solution method for predicting the geometrically nonlinear response of a bonded composite tubular single-lap joint subjected to general loading conditions. The transverse shear and normal stresses in the adhesive as well as membrane stress resultants and bending moments in the adherends are determined using this method. The method utilizes the principle of virtual work in conjunction with nonlinear thin-shell theory to model the adherends and a cylindrical shear lag model to represent the kinematics of the thin adhesive layer between the adherends. The kinematic boundary conditions are imposed by employing the Lagrange multiplier method. In the solution procedure, the displacement components for the tubular joint are approximated in terms of non-periodic and periodic B-Spline functions in the longitudinal and circumferential directions, respectively. The approach presented herein represents a rapid-solution alternative to the finite element method. The solution method was validated by comparison against a previously considered tubular single-lap joint. The steep variation of both peeling and shearing stresses near the adhesive edges was successfully captured. The applicability of the present method was also demonstrated by considering tubular bonded lap-joints subjected to pure bending and torsion.

  19. Residual Strength Analyses of Riveted Lap-Splice Joints

    NASA Technical Reports Server (NTRS)

    Seshadri, B. R.; Newman, J. C., Jr.

    2000-01-01

    The objective of this paper was to analyze the crack-linkup behavior in riveted-stiffened lap-splice joint panels with small multiple-site damage (MSD) cracks at several adjacent rivet holes. Analyses are based on the STAGS (STructural Analysis of General Shells) code with the critical crack-tip-opening angle (CTOA) fracture criterion. To account for high constraint around a crack front, the "plane strain core" option in STAGS was used. The importance of modeling rivet flexibility with fastener elements that accurately model load transfer across the joint is discussed. Fastener holes are not modeled but rivet connectivity is accounted for by attaching rivets to the sheet on one side of the cracks that simulated both the rivet diameter and MSD cracks. Residual strength analyses made on 2024-T3 alloy (1.6-mm thick) riveted-lap-splice joints with a lead crack and various size MSD cracks were compared with test data from Boeing Airplane Company. Analyses were conducted for both restrained and unrestrained buckling conditions. Comparison of results from these analyses and results from lap-splice-joint test panels, which were partially restrained against buckling indicate that the test results were bounded by the failure loads predicted by the analyses with restrained and unrestrained conditions.

  20. Investigation into Interface Lifting Within FSW Lap Welds

    SciTech Connect

    K. S. Miller; C. R. Tolle; D. E. Clark; C. I. Nichol; T. R. McJunkin; H. B. Smartt

    2008-06-01

    Friction stir welding (FSW) is rapidly penetrating the welding market in many materials and applications, particularly in aluminum alloys for transportation applications. As this expansion outside the research laboratory continues, fitness for service issues will arise, and process control and NDE methods will become important determinants of continued growth. The present paper describes research into FSW weld nugget flaw detection within aluminum alloy lap welds. We present results for two types of FSW tool designs: a smooth pin tool and a threaded pin tool. We show that under certain process parameters (as monitored during welding with a rotating dynamometer that measures x, y, z, and torque forces) and tooling designs, FSW lap welds allow significant nonbonded interface lifting of the lap joint, while forming a metallurgical bond only within the pin region of the weld nugget. These lifted joints are often held very tightly together even though unbonded, and might be expected to pass cursory NDE while representing a substantial compromise in joint mechanical properties. The phenomenon is investigated here via radiographic and ultrasonic NDE techniques, with a copper foil marking insert (as described elsewhere) and by the tensile testing of joints. As one would expect, these results show that tool design and process parameters significantly affect plactic flow and this lifted interface. NDE and mechanical strength ramifications of this defect are discussed.

  1. Biomaterials for periodontal regeneration

    PubMed Central

    Shue, Li; Yufeng, Zhang; Mony, Ullas

    2012-01-01

    Periodontal disease is characterized by the destruction of periodontal tissues. Various methods of regenerative periodontal therapy, including the use of barrier membranes, bone replacement grafts, growth factors and the combination of these procedures have been investigated. The development of biomaterials for tissue engineering has considerably improved the available treatment options above. They fall into two broad classes: ceramics and polymers. The available ceramic-based materials include calcium phosphate (eg, tricalcium phosphate and hydroxyapatite), calcium sulfate and bioactive glass. The bioactive glass bonds to the bone with the formation of a layer of carbonated hydroxyapatite in situ. The natural polymers include modified polysaccharides (eg, chitosan,) and polypeptides (collagen and gelatin). Synthetic polymers [eg, poly(glycolic acid), poly(L-lactic acid)] provide a platform for exhibiting the biomechanical properties of scaffolds in tissue engineering. The materials usually work as osteogenic, osteoconductive and osteoinductive scaffolds. Polymers are more widely used as a barrier material in guided tissue regeneration (GTR). They are shown to exclude epithelial downgrowth and allow periodontal ligament and alveolar bone cells to repopulate the defect. An attempt to overcome the problems related to a collapse of the barrier membrane in GTR or epithelial downgrowth is the use of a combination of barrier membranes and grafting materials. This article reviews various biomaterials including scaffolds and membranes used for periodontal treatment and their impacts on the experimental or clinical management of periodontal defect. PMID:23507891

  2. Stress increases periodontal inflammation

    PubMed Central

    RIVERA, CÉSAR; MONSALVE, FRANCISCO; SUAZO, IVÁN; BECERRA, JAVIERA

    2012-01-01

    This study aimed to examine the effect of chronic restraint stress (RS) on the severity of experimental periodontal disease in rats. A total of 32 male Sprague Dawley (SD) rats were divided into four groups: i) Rats receiving two treatment regimens, chronic stress induced by movement restriction in acrylic cylinders for 1–1.5 h daily and induction of experimental periodontal disease, using a nylon ligature which was placed around the first left mandibular molars (n=8); ii) induction of periodontal disease, without RS (n=8); iii) RS (n=8) and iv) control (n=8). After 15 days, blood samples were obtained, and blood glucose levels and the corticosterone concentration were measured as stress markers. The severity of periodontal disease was analyzed according to the level of gingival and bone inflammation, leading to compromise of the teeth involved. Chronic stress was induced with movement restriction (P≤0.05, Mann-Whitney U-test) and increased the severity (P≤0.05, Mann-Whitney U-test) of experimental perio dontal disease in rats, according to the level of gingival and bone inflammation around the first left mandibular molars. The results of the present study showed that RS modulates periodontal inflammation and that the rat model described herein is suitable for investigating the association between stress and periodontal disease. PMID:23226743

  3. Assembly of lipopolysaccharide in Escherichia coli requires the essential LapB heat shock protein.

    PubMed

    Klein, Gracjana; Kobylak, Natalia; Lindner, Buko; Stupak, Anna; Raina, Satish

    2014-05-23

    Here, we describe two new heat shock proteins involved in the assembly of LPS in Escherichia coli, LapA and LapB (lipopolysaccharide assembly protein A and B). lapB mutants were identified based on an increased envelope stress response. Envelope stress-responsive pathways control key steps in LPS biogenesis and respond to defects in the LPS assembly. Accordingly, the LPS content in ΔlapB or Δ(lapA lapB) mutants was elevated, with an enrichment of LPS derivatives with truncations in the core region, some of which were pentaacylated and exhibited carbon chain polymorphism. Further, the levels of LpxC, the enzyme that catalyzes the first committed step of lipid A synthesis, were highly elevated in the Δ(lapA lapB) mutant. Δ(lapA lapB) mutant accumulated extragenic suppressors that mapped either to lpxC, waaC, and gmhA, or to the waaQ operon (LPS biosynthesis) and lpp (Braun's lipoprotein). Increased synthesis of either FabZ (3-R-hydroxymyristoyl acyl carrier protein dehydratase), slrA (novel RpoE-regulated non-coding sRNA), lipoprotein YceK, toxin HicA, or MurA (UDP-N-acetylglucosamine 1-carboxyvinyltransferase) suppressed some of the Δ(lapA lapB) defects. LapB contains six tetratricopeptide repeats and, at the C-terminal end, a rubredoxin-like domain that was found to be essential for its activity. In pull-down experiments, LapA and LapB co-purified with LPS, Lpt proteins, FtsH (protease), DnaK, and DnaJ (chaperones). A specific interaction was also observed between WaaC and LapB. Our data suggest that LapB coordinates assembly of proteins involved in LPS synthesis at the plasma membrane and regulates turnover of LpxC, thereby ensuring balanced biosynthesis of LPS and phospholipids consistent with its essentiality.

  4. Crystal structure of XoLAP, a leucine aminopeptidase, from Xanthomonas oryzae pv. oryzae.

    PubMed

    Kim, Jin-Kwang; Natarajan, Sampath; Park, Hanseul; Huynh, Kim-Hung; Lee, Sang Hee; Kim, Jeong-Gu; Ahn, Yeh-Jin; Kang, Lin-Woo

    2013-10-01

    Aminopeptidases are metalloproteinases that degrade N-terminal residues from protein and play important roles in cell growth and development by controlling cell homeostasis and protein maturation. We determined the crystal structure of XoLAP, a leucyl aminopeptidase, at 2.6 Å resolution from Xanthomonas oryzae pv. oryzae, causing the destructive rice disease of bacterial blight. It is the first crystal structure of aminopeptidase from phytopathogens as a drug target. XoLAP existed as a hexamer and the monomer structure consisted of an N-terminal cap domain and a C-terminal peptidase domain with two divalent zinc ions. XoLAP structure was compared with BlLAP and EcLAP (EcPepA) structures. Based on the structural comparison, the molecular model of XoLAP in complex with the natural aminopeptidase inhibitor of microginin FR1 was proposed. The model structure will be useful to develop a novel antibacterial drug against Xoo.

  5. Apparatus and method for lapping an edge surface of an object

    NASA Technical Reports Server (NTRS)

    Rossi, Vito N. (Inventor)

    1989-01-01

    An apparatus for lapping an edge surface of an object comprises a block having a side adapted to engage a wide surface of an object, adjustable spacers disposed on the block and adapted to engage a lap plate, and a weighted spring disposed on the block for urging the spacers and the object edge surface towards the lap plate. A method for lapping comprises setting surfaces of adjustable spacers disposed on a block to be substantially the same distance from the block, affixing a wide surface of an object to the block, urging an edge surface of the object and the spacers towards a lap plate, lapping the edge of the object, inspecting the edge for parallelism to a reference line, resetting the spacers and relapping the edge surface.

  6. [Periodontitis and tissue regeneration].

    PubMed

    Yamazaki, Kazuhisa

    2005-08-01

    Chronic periodontitis is a destructive disease that affects the supporting structures of the teeth including periodontal ligament, cementum, and alveolar bone. If left untreated, patients may lose multiple teeth and extensive prosthetic treatment will be required. In order to re-engineer lost tooth-supporting tissues, various therapeutic modalities have been used clinically. Periodontal regeneration procedures including guided tissue regeneration have achieved substantial effects. However, there are several issues to be solved. They are highly technique-sensitive, applicable to limited cases which are susceptible to treatment, and supposed to have relatively low predictability. Therefore, it is necessary to develop new approaches to improve the predictability and effectiveness of regenerative therapies for periodontal tissues. Recently, the concept of tissue engineering has been introduced to restore lost tissues more effectively where the biological process of healing is mimicked. To achieve this, integration of three key elements is required: progenitor/stem cells, growth factors and the extracellular matrix scaffold. Although it has been shown that implantation of bone marrow-derived mesenchymal stem cells into periodontal osseous defects induced regeneration of cementum, periodontal ligament and alveolar bone in dogs, further extensive preclinical studies are required. On the other hand, application of growth factors, particularly basic fibroblast growth factor in the treatment of human periodontitis, is promising and is now in clinical trial. Furthermore, the rate of release of growth factor from the scaffold also can profoundly affect the results of tissue engineering strategies and the development of new materials is expected. In addition, as tissue regenerative potential is negatively regulated by aging, the effects of aging have to be clarified to gain complete regeneration.

  7. Estimation and comparison of serum cortisol levels in periodontally diseased patients and periodontally healthy individuals: A clinical-biochemical study

    PubMed Central

    Rohini, G.; Kalaivani, S.; Kumar, Vipin; Rajasekar, S. A.; Tuckaram, Jaishree; Pandey, Vinisha

    2015-01-01

    Introduction: Psychological conditions, particularly psychosocial stress have been implicated as risk indicators of periodontal disease. Stress increases cortisol production from the adrenal cortex by stimulating an increase in the release of ACTH from the pituitary gland. Increased cortisol production suppresses the immune response and increases the potential of periodontal tissue destruction. Aim: The aim of the present study was to estimate and compare the serum cortisol levels in periodontally diseased patients and periodontally healthy individuals. Materials and Methods: Total of 45 subjects were recruited for this study and were categorized into three groups. Group I - Comprised of aggressive periodontitis patients (n = 15), Group II - Chronic periodontitis patients (n = 15), and Group III - Healthy controls (n = 15). Serum samples were collected from each of the groups and cortisol levels were determined using cortisol immunoassay kit. Clinical examination covered probing depth, gingival index (GI), gingival recession, plaque index, and clinical attachment level. The statistical analysis was done using nonparameteric t-test and Spearman's rank correlation coefficient. Results: With respect to cortisol, the levels were higher in Group-I compared to the other groups. On comparison of mean cortisol levels among the groups, the values were statistically significant between Group-I and Group-III. Group-I showed a significant negative correlation between cortisol levels and GI. Conclusion: Within the limits of the study serum cortisol levels was higher in the chronic periodontitis group compared to the other groups. Positive correlation was found between the cortisol levels and other clinical parameters except for the GI. PMID:26538897

  8. Alcohol and Aggression.

    ERIC Educational Resources Information Center

    Gustafson, Roland

    1994-01-01

    Reviews the acute effects of alcohol on aggressive responding. From experimental studies that use human subjects, it is concluded that a moderate dose of alcohol does not increase aggression if subjects are unprovoked. Under provocative situations, aggression is increased as a function of alcohol intoxication, provided that subjects are restricted…

  9. Periodontal therapy for severe chronic periodontitis with periodontal regeneration and different types of prosthesis.

    PubMed

    Kinumatsu, Takashi; Umehara, Kazuhiro; Nagano, Kyosuke; Saito, Atsushi

    2014-01-01

    We report a patient with severe chronic periodontitis requiring regenerative periodontal surgery and different types of prosthesis in the maxillary and mandibular regions. The patient was a 57-year-old woman who presented with the chief complaint of occlusal pain. An initial clinical examination revealed that 73% of sites had a probing depth of ≥4 mm, and 60% of sites exhibiting bleeding on probing. Radiographic examination revealed vertical bone defects in the molar region and widening of the periodontal ligament space around teeth #17 and 24. Initial periodontal therapy was implemented based on a clinical diagnosis of severe chronic periodontitis. Surgical periodontal therapy was subsequently performed at selected sites. Periodontal regenerative therapy using enamel matrix derivative was performed on #14, 15, and 35-37. Tunnel preparation was performed on #46 as it had a 2-wall vertical bony defect and Degree 3 furcation involvement. Other sites with residual periodontal pockets were treated by modified Widman flap surgery. After a re-evaluation, functional rehabilitation was implemented with a removable maxillary partial denture and a fixed mandibular bridge. No further deterioration was observed in the periodontal condition of most of the teeth during a 2-year period of supportive periodontal therapy (SPT). The patient is currently still undergoing SPT and some minor problems remain. However, the results suggest that treatment and subsequent maintenance for severe periodontitis with traumatic occlusion can be successful as long as the appropriate periodontal and prosthodontic treatment is planned and careful SPT carried out.

  10. Bilateral lateral periodontal cyst.

    PubMed

    Govil, Somya; Gupta, Vishesh; Misra, Neeta; Misra, Pradyumna

    2013-05-10

    The bilateral lateral periodontal cyst is a rare nasological entity, which despite clinical and radiological presentation is being diagnosed by histological characteristics. It is asymptomatic in nature and is observed in routine radiography. The aim and objective of this article is to present a rare case of bilateral lateral periodontal cyst in a 14-year-old child. The clinical and radiographical findings, along with its management have been discussed. Enucleation of bilateral cyst without extraction of the adjacent tooth was performed. Lesion samples were sent for histopathological analysis. The histopathological analysis revealed a thin, non keratinised stratified squamous epithelium resembling reduced enamel epithelium. Epithelial plaques were also seen. A clinicopathological correlation incorporating the surgical, radiographical and gold standard histopathological findings was obtained to suggest the final diagnosis of the bilateral lateral periodontal cyst.

  11. Hearing regulates Drosophila aggression.

    PubMed

    Versteven, Marijke; Vanden Broeck, Lies; Geurten, Bart; Zwarts, Liesbeth; Decraecker, Lisse; Beelen, Melissa; Göpfert, Martin C; Heinrich, Ralf; Callaerts, Patrick

    2017-02-21

    Aggression is a universal social behavior important for the acquisition of food, mates, territory, and social status. Aggression in Drosophila is context-dependent and can thus be expected to involve inputs from multiple sensory modalities. Here, we use mechanical disruption and genetic approaches in Drosophila melanogaster to identify hearing as an important sensory modality in the context of intermale aggressive behavior. We demonstrate that neuronal silencing and targeted knockdown of hearing genes in the fly's auditory organ elicit abnormal aggression. Further, we show that exposure to courtship or aggression song has opposite effects on aggression. Our data define the importance of hearing in the control of Drosophila intermale aggression and open perspectives to decipher how hearing and other sensory modalities are integrated at the neural circuit level.

  12. Progressive damage in single lap countersunk composite joints

    NASA Astrophysics Data System (ADS)

    Chishti, Maajid; Wang, Chun Hui; Thomson, Rodney S.; Orifici, Adrian

    2010-06-01

    This paper presents an experimental and computational investigation of the influences of countersink and bolt torque on the progressive failure of single-lap composite joint. Using the Abaqus® software, delamination damage and ply fracture are modelled using cohesive element approach and continuum damage mechanics method, respectively. The model is first validated against a filled-hole tension test to calibrate the composite damage model. Comparison with the experimental results indicates that the computational model is capable of accurately predicting the joint strength and the damage progression process.

  13. Periodontitis in Chronic Heart Failure

    PubMed Central

    Fröhlich, Hanna; Herrmann, Kristina; Franke, Jennifer; Karimi, Alamara; Täger, Tobias; Cebola, Rita; Katus, Hugo A.; Zugck, Christian

    2016-01-01

    Periodontal disease has been associated with an increased risk of cardiovascular events. The purpose of our study was to investigate whether a correlation between periodontitis and chronic heart failure exists, as well as the nature of the underlying cause. We enrolled 71 patients (mean age, 54 ± 13 yr; 56 men) who had stable chronic heart failure; all underwent complete cardiologic and dental evaluations. The periodontal screening index was used to quantify the degree of periodontal disease. We compared the findings to those in the general population with use of data from the 4th German Dental Health Survey. Gingivitis, moderate periodontitis, and severe periodontitis were present in 17 (24%), 17 (24%), and 37 (52%) patients, respectively. Severe periodontitis was more prevalent among chronic heart failure patients than in the general population. In contrast, moderate periodontitis was more prevalent in the general population (P <0.00001). The severity of periodontal disease was not associated with the cause of chronic heart failure or the severity of heart failure symptoms. Six-minute walking distance was the only independent predictor of severe periodontitis. Periodontal disease is highly prevalent in chronic heart failure patients regardless of the cause of heart failure. Prospective trials are warranted to clarify the causal relationship between both diseases. PMID:27547136

  14. Micro topography of different material surface by solid abrasive lapped at high speed

    NASA Astrophysics Data System (ADS)

    Tian, Chunlin; Yang, Jiandong; Fan, Jingfeng; Zhou, Huawen

    2007-12-01

    The principle of solid abrasives lapping is that the abrasives are fixed and made into a special lapping tool; the workpiece is lapped in high speed lapping machine tool. It possesses many advantages compared with traditional low speed lapping with particulate abrasives, e.g. high machining efficiency, low machining cost, high and stable machining accuracy. So the highly efficient lapping method has been paid close attention to. This paper made a study on surface micro topography of different material by solid abrasive lapped at high speed. In experiments the lapping technique parameter is fixed, and different workpiece which are made by T10 steel, carbide, ceramic glass and alumina ceramics are lapped. The surface micro topography is measured by SEM, from the measuring result, it can be known that there is some shallow scribe on the surface of T10 steel, and the obvious plastic deformation can be observed. The SEM pictures show that there is some scribe on the surface of ceramics glass after lapped, with more magnification times many micro cracking and some plastic hump can be observed on the scribe. These scribes and humps are first cause of depressing surface quality, and these micro cracking can result in a lot of diffuse reflection on workpiece surface, it decreases the glossiness of mirror surface. On the surface of alumina ceramics there are a lot of defects, the size of such defect is more than the scribe of abrasive, it can be sure that the defect is not produced by lapping, so the material quality is an important effect fact to surface macro topography. On the surface of carbide there are a little of scribe and air cavity, and the scribe is very shallow; the defect of powder metallurgy martial is the primary reason.

  15. Lasers in periodontics.

    PubMed

    Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie

    2012-08-01

    Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20(th) century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics.

  16. Functional differences of Porphyromonas gingivalis Fimbriae in determining periodontal disease pathogenesis: a literature review.

    PubMed

    Moreno, Sandra; Contreras, Adolfo

    2013-01-01

    Porphyromonas gingivalis is implicated in chronic and aggressive periodontitis. This bacterium has numerous virulence factors and one is the Fimbriae, which is quite important for bacterial colonization. Fimbriae are appendices that anchor to the bacterial wall and are comprised of the protein FimBriline encoded by the FimA gene. Thus far, six genotypes have been identified, FimA I to V and Ib. Genotypes II and IV are associated with periodontal disease, while genotype I is related to gingival health. Genotype identification of P. gingivalis FimA in periodontitis would be important to confirm the pathogenic genotypes and to establish risk at population level. This review is about the P. gingivalis FimA genotype prevalence worldwide. A systematic search using Pubmed, Hinary, and Science Direct within the following descriptors: Porphyromonas gingivalis, bacterial adhesion, periodontitis, Fimbriae, FimA, genotipification was performed to April 2011.

  17. Functional differences of Porphyromonas gingivalis Fimbriae in determining periodontal disease pathogenesis: a literature review

    PubMed Central

    Contreras, Adolfo

    2013-01-01

    Porphyromonas gingivalis is implicated in chronic and aggressive periodontitis. This bacterium has numerous virulence factors and one is the Fimbriae, which is quite important for bacterial colonization. Fimbriae are appendices that anchor to the bacterial wall and are comprised of the protein FimBriline encoded by the FimA gene. Thus far, six genotypes have been identified, FimA I to V and Ib. Genotypes II and IV are associated with periodontal disease, while genotype I is related to gingival health. Genotype identification of P. gingivalis FimA in periodontitis would be important to confirm the pathogenic genotypes and to establish risk at population level. This review is about the P. gingivalis FimA genotype prevalence worldwide. A systematic search using Pubmed, Hinary, and Science Direct within the following descriptors: Porphyromonas gingivalis, bacterial adhesion, periodontitis, Fimbriae, FimA, genotipification was performed to April 2011. PMID:24892323

  18. LAP (NF-IL-6), a tissue-specific transcriptional activator, is an inhibitor of hepatoma cell proliferation.

    PubMed Central

    Buck, M; Turler, H; Chojkier, M

    1994-01-01

    During postnatal liver development, LAP (NF-IL-6, C/EBP beta) expression and hepatocyte proliferation are mutually exclusive. In addition to transactivating liver-specific genes, LAP, but not C/EBP alpha, arrests the cell cycle before the G1/S boundary in hepatoma cells. LIP, a liver-inhibitory protein, which is translated from LAP mRNA lacking the activation domain of LAP, is not only ineffective in blocking hepatoma cell proliferation but also antagonizes the effect of LAP on the cell cycle. Deletion analysis indicated that this effect of LIP required only the DNA-binding and leucine zipper domains. In addition we found that integrity of the LAP dimerization and activation domains is indispensable for the arrest of cell proliferation induced by LAP. Thus, hepatocyte differentiation and its characteristic quiescent state may be modulated by the LAP/LIP ratio. Images PMID:7906646

  19. Analysis of the ’Joggle-Lap’ Joint for Automotive Applications.

    DTIC Science & Technology

    2007-11-02

    An analytical model is developed to describe the response of the ’ joggle -lap’ joint to both tensile and bending loads. The model consists of a non...8217 joggle -lap’ joint due to tensile loads was verified through experimental testing and ultimate loads were accurately predicted within experimental error

  20. Machine Shop I. Learning Activity Packets (LAPs). Section B--Basic and Related Technology.

    ERIC Educational Resources Information Center

    Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains eight learning activity packets (LAPs) for the "basic and related technology" instructional area of a Machine Shop I course. The eight LAPs cover the following topics: basic mathematics, blueprints, rules, micrometer measuring tools, Vernier measuring tools, dial indicators, gaging and inspection tools, and…

  1. Epstein–Barr virus is associated with periodontal diseases

    PubMed Central

    Gao, Zilong; Lv, Juan; Wang, Min

    2017-01-01

    Abstract Some controversies still exist between the detection of Epstein–Barr virus (EBV)'s DNA and risks of periodontal diseases. Hence, a comprehensive meta-analysis on all available literatures was performed to clarify the relationship between EBV and preidontitis. A comprehensive search was conducted within the PUBMED, EMBASE, and WANFANG databases up to October 10th, 2016 according to inclusion and exclusion criteria and finally 21 case–control literatures were obtained. The outcomes including odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. Publication bias was determined by Begg or Egger test. Sensitivity analysis was used to investigate reliability and stability of the results. According to the data from included trials, the association between overall increased risks of periodontitis and the detection of EBV was significant (OR = 6.199, 95% CI = 3.119–12.319, P < 0.001). In the disease-type analysis, the pooled ORs for chronic periodontitis and aggressive periodontitis were 6.586 (95% CI = 3.042–14.262, P < 0.001) and 8.361 (95% CI = 2.109–33.143, P = 0.003), respectively. In the subgroup analysis of ethnicity, our results suggested that high EBV-detecting frequencies were correlated with increased risks of periodontitis in Asians, Europeans, and Americans (P < 0.001). Subgroup analysis by the sample type showed that subgingival plaque (SgP) samples and tissue samples were available for EBV detecting (P < 0.001). Detecting EBV of samples in ≥5 (6) mm sites of periodontal pockets were easier than in ≤3-mm sites (P = 0.023). This meta-analysis indicates that high frequent detection of EBV correlates with increased risk of periodontal diseases. SgP and tissue are available for detecting EBV in patients of periodontitis. At last, our results suggest that detecting EBV of samples in =5 (6) mm sites of periodontal pockets are more sensitive than in ≤3

  2. Nonlinear Analysis of Bonded Composite Single-LAP Joints

    NASA Technical Reports Server (NTRS)

    Oterkus, E.; Barut, A.; Madenci, E.; Smeltzer, S. S.; Ambur, D. R.

    2004-01-01

    This study presents a semi-analytical solution method to analyze the geometrically nonlinear response of bonded composite single-lap joints with tapered adherend edges under uniaxial tension. The solution method provides the transverse shear and normal stresses in the adhesive and in-plane stress resultants and bending moments in the adherends. The method utilizes the principle of virtual work in conjunction with von Karman s nonlinear plate theory to model the adherends and the shear lag model to represent the kinematics of the thin adhesive layer between the adherends. Furthermore, the method accounts for the bilinear elastic material behavior of the adhesive while maintaining a linear stress-strain relationship in the adherends. In order to account for the stiffness changes due to thickness variation of the adherends along the tapered edges, their in-plane and bending stiffness matrices are varied as a function of thickness along the tapered region. The combination of these complexities results in a system of nonlinear governing equilibrium equations. This approach represents a computationally efficient alternative to finite element method. Comparisons are made with corresponding results obtained from finite-element analysis. The results confirm the validity of the solution method. The numerical results present the effects of taper angle, adherend overlap length, and the bilinear adhesive material on the stress fields in the adherends, as well as the adhesive, of a single-lap joint

  3. Ultrasonic guided wave inspection of Inconel 625 brazed lap joints

    NASA Astrophysics Data System (ADS)

    Comot, Pierre; Bocher, Philippe; Belanger, Pierre

    2016-04-01

    The aerospace industry has been investigating the use of brazing for structural joints, as a mean of reducing cost and weight. There therefore is a need for a rapid, robust, and cost-effective non-destructive testing method for evaluating the structural integrity of the joints. The mechanical strength of brazed joints depends mainly on the amount of brittle phases in their microstructure. Ultrasonic guided waves offer the possibility of detecting brittle phases in joints using spatio-temporal measurements. Moreover, they offer the opportunity to inspect complex shape joints. This study focused on the development of a technique based on ultrasonic guided waves for the inspection of Inconel 625 lap joints brazed with BNi-2 filler metal. A finite element model of a lap joint was used to optimize the inspection parameters and assess the feasibility of detecting the amount of brittle phases in the joint. A finite element parametric study simulating the input signal shape, the center frequency, and the excitation direction was performed. The simulations showed that the ultrasonic guided wave energy transmitted through, and reflected from, the joints was proportional to the amount of brittle phases in the joint.

  4. Edge effect modeling and experiments on active lap processing.

    PubMed

    Liu, Haitao; Wu, Fan; Zeng, Zhige; Fan, Bin; Wan, Yongjian

    2014-05-05

    Edge effect is regarded as one of the most difficult technical issues for fabricating large primary mirrors, especially for large polishing tools. Computer controlled active lap (CCAL) uses a large size pad (e.g., 1/3 to 1/5 workpiece diameters) to grind and polish the primary mirror. Edge effect also exists in the CCAL process in our previous fabrication. In this paper the material removal rules when edge effects happen (i.e. edge tool influence functions (TIFs)) are obtained through experiments, which are carried out on a Φ1090-mm circular flat mirror with a 375-mm-diameter lap. Two methods are proposed to model the edge TIFs for CCAL. One is adopting the pressure distribution which is calculated based on the finite element analysis method. The other is building up a parametric equivalent pressure model to fit the removed material curve directly. Experimental results show that these two methods both effectively model the edge TIF of CCAL.

  5. Multicrack growth monitoring at riveted lap joints using piezoelectric patches

    NASA Astrophysics Data System (ADS)

    Ihn, Jeong-Beom; Chang, Fu-Kuo

    2002-06-01

    A built-in cost-effective diagnostic system is being developed to monitor fatigue crack growth in aircraft structures. The proposed system consists of a SMART Layer by Acellent Technologies with an embedded network of distributed piezoelectric sensors/actuators, a diagnostic unit, and software. Multi-riveted aluminum lap joints (936 x 462 mm) were tested for a constant amplitude fatigue test under tensile loading to monitor crack growth at rivet holes. A SMART Layer was designed as a strip and surface-mounted to the critical area of lap joints where crack initiation and growth were suspected. The SMART Layer installed between the two rivet rows was used as an actuator strip and the other layer located below the rivets was used as a sensor strip. Using the software, pre-selected diagnostic signals from a designated piezoelectric actuator to its neighboring sensors were generated by the diagnostic unit. A corresponding sensor signals were recorded and compared to a previously recorded baseline reference. The signal processing technique and interpretation algorithm were developed and implemented for extracting features related to crack growth condition at the time of measurement. The results of estimates were compared with non-destructive testing (NDT) data taken from the experiments, which were conducted during the course of the investigation. The probability of damage detection, compared to conventional NDT techniques, was evaluated.

  6. Lap Shear Testing of Candidate Radiator Panel Adhesives

    NASA Technical Reports Server (NTRS)

    Ellis, David; Briggs, Maxwell; McGowan, Randy

    2013-01-01

    During testing of a subscale radiator section used to develop manufacturing techniques for a full-scale radiator panel, the adhesive bonds between the titanium heat pipes and the aluminum face sheets failed during installation and operation. Analysis revealed that the thermal expansion mismatch between the two metals resulted in relatively large shear stresses being developed even when operating the radiator at moderate temperatures. Lap shear testing of the adhesive used in the original joints demonstrated that the two-part epoxy adhesive fell far short of the strength required. A literature review resulted in several candidate adhesives being selected for lap shear joint testing at room temperature and 398 K, the nominal radiator operating temperature. The results showed that two-part epoxies cured at room and elevated temperatures generally did not perform well. Epoxy film adhesives cured at elevated temperatures, on the other hand, did very well with most being sufficiently strong to cause yielding in the titanium sheet used for the joints. The use of an epoxy primer generally improved the strength of the joint. Based upon these results, a new adhesive was selected for the second subscale radiator section.

  7. Chaotic and ambient vibration analysis of composite lap joint damage

    NASA Astrophysics Data System (ADS)

    Pecora, Lou; Nichols, Jon; Seaver, Mark; Trickey, Steve; Motley, Sara

    2007-04-01

    We examined strain time series from fiber Bragg gratings sensors located in various positions on a composite material beam attached to a steel plate by a lap joint. The beam was vibrated using both broad-band chaotic signals (Lorenz system), and a narrow band signal conforming to the Pierson-Moskowitz frequency distribution for wave height (ambient excitation). The system was damaged by decreasing the torque on instrumented bolts in the lap joint from very tight all the way through to a joint with a gap and slippage. We analyzed the strain data by reconstructing the attractor of the system in the case of chaotic forcing and a pseudo-attractor in the case of sea-wave forcing. Using the highest torque case as an "undamaged" baseline, we calculated the continuity statistic between the baseline attractor and the attractors of the various damage levels for both forcing cases. We show where one can and cannot say that the functional relationship between the attractors changes and how those changes are related to damage levels.

  8. Large-Scale Advanced Prop-Fan (LAP)

    NASA Technical Reports Server (NTRS)

    Degeorge, C. L.

    1988-01-01

    In recent years, considerable attention has been directed toward improving aircraft fuel efficiency. Analytical studies and research with wind tunnel models have demonstrated that the high inherent efficiency of low speed turboprop propulsion systems may now be extended to the Mach .8 flight regime of today's commercial airliners. This can be accomplished with a propeller, employing a large number of thin highly swept blades. The term Prop-Fan has been coined to describe such a propulsion system. In 1983 the NASA-Lewis Research Center contracted with Hamilton Standard to design, build and test a near full scale Prop-Fan, designated the Large Scale Advanced Prop-Fan (LAP). This report provides a detailed description of the LAP program. The assumptions and analytical procedures used in the design of Prop-Fan system components are discussed in detail. The manufacturing techniques used in the fabrication of the Prop-Fan are presented. Each of the tests run during the course of the program are also discussed and the major conclusions derived from them stated.

  9. Behavioral comparison of sucrose and l-2-amino-4-phosphonobutyrate (L-AP4) tastes in rats: does L-AP4 have a sweet taste?

    PubMed

    Eschle, B K; Eddy, M C; Spang, C H; Delay, E R

    2008-08-13

    Even though it is generally thought that umami stimuli such as monosodium glutamate (MSG) and sweet stimuli such as sucrose are detected by different taste receptors, these stimuli appear to share taste qualities when amiloride (a sodium channel blocker) is present to reduce the sodium taste. Single fiber recording studies of the facial and glossopharyngeal nerves have shown that encoding of L-2-amino-4-phosphonobutyrate (L-AP4), a potent mGluR4 agonist that elicits a taste quite similar to MSG, may occur in the same fibers that also encode sweet stimuli. This suggests that L-AP4 and sweet substances may activate common receptors or afferent signaling mechanisms. We report results of behavioral experiments that test this hypothesis. In the first study, rats conditioned to avoid sucrose or L-AP4 generalized the aversion to the opposite substance, indicating that both substances elicited similar tastes. However, two taste discrimination experiments showed that rats easily discriminated between sucrose and L-AP4 over a wide range of concentrations, even when the cue function of sodium associated with L-AP4 was reduced by amiloride and neutralized by adding equimolar concentrations of NaCl to sucrose. These data suggest that even though L-AP4 and sucrose elicit similar taste qualities, one or both substances also elicit other taste qualities not shared by the opposite substance. They also suggest that the taste-mGluR4 receptor and the signal pathway activated by L-AP4 are not the same as those activated by sucrose. These data, when combined with fiber recording data, suggest that there is convergence of L-AP4 and sucrose signals at some point early in the gustatory pathway.

  10. Periodontics II: Course Proposal.

    ERIC Educational Resources Information Center

    Dordick, Bruce

    A proposal is presented for Periodontics II, a course offered at the Community College of Philadelphia to give the dental hygiene/assisting student an understanding of the disease states of the periodontium and their treatment. A standardized course proposal cover form is given, followed by a statement of purpose for the course, a list of major…

  11. Lasers in periodontal therapy.

    PubMed

    Passanezi, Euloir; Damante, Carla Andreotti; de Rezende, Maria L Rubo; Greghi, Sebastião L Aguiar

    2015-02-01

    About 50 years ago, lasers started to be used in periodontal treatment following evidence that wounds produced in animals healed more quickly after being irradiated with low-intensity lasers. Increased production of growth factors, stimulated mainly by red and infrared lasers, may participate in this process by influencing the behavior of various types of cells. High-intensity lasers have been used as an alternative to nonsurgical periodontal therapy in root biomodification and to reduce dentin hypersensivity; low-intensity lasers are frequently employed to improve tissue repair in regenerative procedures and in antimicrobial photodynamic therapy. Despite the abundance of promising data on the advantages of their use, there is still controversy regarding the real benefits of lasers and antimicrobial photodynamic therapy in periodontal and peri-implant treatment. A huge variation in the parameters of laser application among studies makes comparisons very difficult. An overview of the current concepts and findings on lasers in periodontal therapy is presented with emphasis on data collected from Latin-American researchers.

  12. Role of LAP+CD4+ T cells in the tumor microenvironment of colorectal cancer

    PubMed Central

    Zhong, Wu; Jiang, Zhi-Yuan; Zhang, Lei; Huang, Jia-Hao; Wang, Shi-Jun; Liao, Cun; Cai, Bin; Chen, Li-Sheng; Zhang, Sen; Guo, Yun; Cao, Yun-Fei; Gao, Feng

    2017-01-01

    AIM To investigate the abundance and potential functions of LAP+CD4+ T cells in colorectal cancer (CRC). METHODS Proportions of LAP+CD4+ T cells were examined in peripheral blood and tumor/paratumor tissues of CRC patients and healthy controls using flow cytometry. Expression of phenotypic markers such as forkhead box (Fox)p3, cytotoxic T-lymphocyte-associated protein (CTLA)-4, chemokine CC receptor (CCR)4 and CCR5 was measured using flow cytometry. LAP-CD4+ and LAP+CD4+ T cells were isolated using a magnetic cell-sorting system and cell purity was analyzed by flow cytometry. Real-time quantitative polymerase chain reaction was used to measure expression of cytokines interleukin (IL)-10 and transforming growth factor (TGF)-β. RESULTS The proportion of LAP+CD4+ T cells was significantly higher in peripheral blood from patients (9.44% ± 3.18%) than healthy controls (1.49% ± 1.00%, P < 0.001). Among patients, the proportion of LAP+CD4+ T cells was significantly higher in tumor tissues (11.76% ± 3.74%) compared with paratumor tissues (3.87% ± 1.64%, P < 0.001). We also observed positive correlations between the proportion of LAP+CD4+ T cells and TNM stage (P < 0.001), distant metastasis (P < 0.001) and serum level of carcinoembryonic antigen (P < 0.05). Magnetic-activated cell sorting gave an overall enrichment of LAP+CD4+ T cells (95.02% ± 2.87%), which was similar for LAP-CD4+ T cells (94.75% ± 2.76%). In contrast to LAP-CD4+ T cells, LAP+CD4+ T cells showed lower Foxp3 expression but significantly higher levels of CTLA-4, CCR4 and CCR5 (P < 0.01). LAP+CD4+ T cells expressed significantly larger amounts of IL-10 and TGF-β but lower levels of IL-2, IL-4, IL-17 and interferon-γ, compared with LAP-CD4+ T cells. CONCLUSION LAP+CD4+ T cells accumulated in the tumor microenvironment of CRC patients and were involved in immune evasion mediated by IL-10 and TGF-β. PMID:28210081

  13. TNFA and IL10 Gene Polymorphisms are not Associated with Periodontitis in Brazilians

    PubMed Central

    Moreira, P. R; Costa, J. E; Gomez, R. S; Gollob, K. J; Dutra, W. O

    2009-01-01

    IL-10 and TNF-α are cytokines that have complex and opposing roles in the inflammatory responses. G/A polymorphisms at position –1082 of IL10 and –308 of TNFA genes have been reported to influence the expression of IL-10 and TNF-α, respectively. The aim of this study was to investigate the association between the IL10 (-1082) and TNFA (- 308) gene polymorphisms with different clinical forms or severity of periodontitis in a sample of Brazilian individuals. DNA was obtained from oral swabs of 165 Brazilian individuals, which were divided into three groups: individuals with chronic periodontitis, aggressive periodontitis and individuals without clinical evidence of periodontitis. Evaluation of IL10 and TNFA polymorphisms was performed by RFLP analysis. Statistical analysis of data was performed using the χ2 likelihood ratio and Fisher`s exact test. No significant differences in the genotype and allele distribution of either IL10 or TNFA were observed among individuals with different clinical forms or with different degrees of severity of periodontitis. Moreover, combined analysis of IL10 and TNFA polymorphisms did not show any association with periodontal status. As conclusion, the IL10 and TNFA gene promoter polymorphisms investigated are not associated with different clinical forms of periodontitis or with severity of the disease in the Brazilian population polymorphisms. PMID:19771178

  14. LapF and Its Regulation by Fis Affect the Cell Surface Hydrophobicity of Pseudomonas putida

    PubMed Central

    Lahesaare, Andrio; Ainelo, Hanna; Teppo, Annika; Kivisaar, Maia; Heipieper, Hermann J.; Teras, Riho

    2016-01-01

    The ability of bacteria to regulate cell surface hydrophobicity is important for the adaptation to different environmental conditions. The hydrophobicity of cell surface can be determined by several factors, including outer membrane and surface proteins. In this study, we report that an adhesin LapF influences cell surface hydrophobicity of Pseudomonas putida. Cells lacking LapF are less hydrophobic than wild-type cells in stationary growth phase. Moreover, the overexpression of the global regulator Fis decreases surface hydrophobicity by repressing the expression of lapF. Flow cytometry analysis revealed that bacteria producing LapF are more viable when confronted with methanol (a hydrophilic compound) but are more susceptible to 1-octanol (a hydrophobic compound). Thus, these results revealed that LapF is the hydrophobicity factor for the cell surface of P. putida. PMID:27812186

  15. The Teacher's Lap--A Site of Emotional Well-Being for the Younger Children in Day-Care Groups

    ERIC Educational Resources Information Center

    Hännikäinen, Maritta

    2015-01-01

    This study focuses on a particular relationship between teachers and one- to three-year-old children: the child in the teacher's lap. When, in what situations, does this happen? Who are the children in the teacher's lap? Why are they there? How do children express emotional well-being when in the teacher's lap? Relational, sociocultural and…

  16. Distribution of adipocyte-derived leucine aminopeptidase (A-LAP)/ER-aminopeptidase (ERAP)-1 in human uterine endometrium.

    PubMed

    Shibata, Daijiro; Ando, Hisao; Iwase, Akira; Nagasaka, Tetsuro; Hattori, Akira; Tsujimoto, Masafumi; Mizutani, Shigehiko

    2004-09-01

    Adipocyte-derived leucine aminopeptidase (A-LAP, endoplasmic reticulum aminopeptidase ERAP1) is specialized to produce peptides presented on the class I major histocompatibility complex (MHC) by trimming epitopes to eight or nine residues, in addition to its enzymatic activity to degrade angiotensin II. Previously we identified placental leucine aminopeptidase (P-LAP), another member of the oxytocinase subfamily of aminopeptidases, in human uterine endometrial epithelial cells. Here we analyzed the distribution of A-LAP in human cyclic endometrium. Western blotting analysis showed that A-LAP was present in the endometrial tissue throughout the menstrual cycle. Immunohistochemical (IHC) analysis of A-LAP showed a similar distribution to that of P-LAP. A-LAP was localized predominantly in the endometrial glands and the luminal surface epithelium. However, the intracellular localization change that accompanied apocrine secretion, which was observed in P-LAP, was not shown in A-LAP. Subcellular localization of A-LAP, demonstrated by immunofluorescence, was ER in the cultured glandular epithelial cells. Our results indicate that A-LAP may fit the endometrial localization as an antigen-presenting ER aminopeptidase. Further understanding of the function(s) of A-LAP in the endometrium appear likely to yield insights into the cyclic changes during the normal endometrial cycle.

  17. Periodontal regeneration using periodontal ligament stem cell-transferred amnion.

    PubMed

    Iwasaki, Kengo; Komaki, Motohiro; Yokoyama, Naoki; Tanaka, Yuichi; Taki, Atsuko; Honda, Izumi; Kimura, Yasuyuki; Takeda, Masaki; Akazawa, Keiko; Oda, Shigeru; Izumi, Yuichi; Morita, Ikuo

    2014-02-01

    Periodontal disease is characterized by the destruction of tooth supporting tissues. Regeneration of periodontal tissues using ex vivo expanded cells has been introduced and studied, although appropriate methodology has not yet been established. We developed a novel cell transplant method for periodontal regeneration using periodontal ligament stem cell (PDLSC)-transferred amniotic membrane (PDLSC-amnion). The aim of this study was to investigate the regenerative potential of PDLSC-amnion in a rat periodontal defect model. Cultured PDLSCs were transferred onto amniotic membranes using a glass substrate treated with polyethylene glycol and photolithography. The properties of PDLSCs were investigated by flow cytometry and in vitro differentiation. PDLSC-amnion was transplanted into surgically created periodontal defects in rat maxillary molars. Periodontal regeneration was evaluated by microcomputed tomography (micro-CT) and histological analysis. PDLSCs showed mesenchymal stem cell-like characteristics such as cell surface marker expression (CD90, CD44, CD73, CD105, CD146, and STRO-1) and trilineage differentiation ability (i.e., into osteoblasts, adipocytes, and chondrocytes). PDLSC-amnion exhibited a single layer of PDLSCs on the amniotic membrane and stability of the sheet even with movement and deformation caused by surgical instruments. We observed that the PDLSC-amnion enhanced periodontal tissue regeneration as determined by micro-CT and histology by 4 weeks after transplantation. These data suggest that PDLSC-amnion has therapeutic potential as a novel cell-based regenerative periodontal therapy.

  18. C/EBPβ-LAP*/LAP Expression Is Mediated by RSK/eIF4B-Dependent Signalling and Boosted by Increased Protein Stability in Models of Monocytic Differentiation

    PubMed Central

    Christmann, Martin; Friesenhagen, Judith; Westphal, Andreas; Pietsch, Daniel; Brand, Korbinian

    2015-01-01

    The transcription factor C/EBPβ plays a key role in monocytic differentiation and inflammation. Its small isoform LIP is associated with proliferation at early premonocytic developmental stages and regulated via mTOR-dependent signalling. During later stages of (pre)monocytic differentiation there is a considerable increase in the large C/EBPβ isoforms LAP*/LAP which inhibit proliferation thus supporting terminal differentiation. Here, we showed in different models of monocytic differentiation that this dramatic increase in the LAP*/LAP protein and LAP/LIP ratio was accompanied by an only modest/retarded mRNA increase suggesting an important role for (post)translational mechanisms. We found that LAP*/LAP formation was induced via MEK/RSK-dependent cascades, whereas mTOR/S6K1 were not involved. Remarkably, LAP*/LAP expression was dependent on phosphorylated eIF4B, an acceleratory protein of RNA helicase eIF4A. PKR inhibition reduced the expression of eIF4B and C/EBPβ in an eIF2α-independent manner. Furthermore, under our conditions a marked stabilisation of LAP*/LAP protein occurred, accompanied by reduced chymotrypsin-like proteasome/calpain activities and increased calpastatin levels. Our study elucidates new signalling pathways inducing LAP*/LAP expression and indicates new alternative PKR functions in monocytes. The switch from mTOR- to RSK-mediated signalling to orchestrate eIF4B-dependent LAP*/LAP translation, accompanied by increased protein stability but only small mRNA changes, may be a prototypical example for the regulation of protein expression during selected processes of differentiation/proliferation. PMID:26646662

  19. Comparative bacteriology of juvenile periodontitis.

    PubMed Central

    Moore, W E; Holdeman, L V; Cato, E P; Smibert, R M; Burmeister, J A; Palcanis, K G; Ranney, R R

    1985-01-01

    Statistical comparisons of the floras associated with juvenile periodontitis, severe periodontitis, and moderate periodontitis indicated that differences in the bacterial compositions of affected sites in these populations were not statistically significant. The subgingival flora of affected juvenile periodontitis sites was statistically significantly different from the adjacent supragingival flora and from the subgingival floras of people with healthy gingiva and of children with developing (experimental) gingivitis. However, the subgingival flora of affected juvenile periodontitis sites was not significantly different from the flora of sites with gingival index scores of 1 or 2 in adults with developing (experimental) gingivitis. Of 357 bacterial taxa among over 18,000 isolates, 54 non-treponemal species, 2 treponemal species, and mycoplasma were most associated with diseased periodontal sulci. These species comprised an increasing proportion of the flora during developing gingivitis and constituted over half of the cultivable flora of diseased sites. PMID:3988344

  20. An examination of faying surface fretting in single lap splices

    NASA Astrophysics Data System (ADS)

    Brown, Adam

    While fretting damage in mechanically fastened joints is widely acknowledged as a common source of crack nucleation, little work is available in the open literature on the role that fretting damage plays in the fatigue life of a riveted joint. To expand on the limited knowledge available, a study was undertaken on fretting fatigue in thin-sheet riveted fuselage lap joints. In joints constructed out of 1 mm thick 2024-T3 aluminum sheet the rivet forming load was found to have a significant effect on the location of fretting damage and crack nucleation. This effect was observed for splices riveted with machine countersunk and with universal rivets. The shift in the location of peak fretting damage and crack nucleation with changing rivet forming loads was investigated through numerical and experimental methods. A predictive model based on the critical plane Smith-Watson-Topper strain life equation was applied to the complex geometry of the single lap splice and was shown to be effective in predicting the fretting fatigue life as well as the location of fretting-induced crack nucleation. Basing this model on an explicit finite element simulation allowed for the inclusion of compressive residual stresses generated during rivet forming. Key to the proper functionality of the predictive model was to have a validated finite element model from which results for the stress and strain field in the loaded component could be obtained. In addition to the predictive model, a series of splice coupon and simplified geometry fretting fatigue tests were performed. The tests showed that, at higher rivet forming loads, crack nucleation is on the faying surface away from the hole edge and that the type of surface condition is important to the fretting fatigue life of the splice. The discovery of this variation with surface treatment at high rivet forming loads is important as more research is showing the benefit of using load-controlled rivet forming and higher rivet forming loads in

  1. Diabetes mellitus and periodontal disease.

    PubMed

    Nichols, C; Laster, L L; Bodak-Gyovai, L Z

    1978-02-01

    A sample of 54 patients with diabetes mellitus were subjects to detailed assessment of periodontal disease levels using standard indices. In order to determine whether the severity of periodontal disease was related to the severity of diabets mellitus, a series of parameters of the diabetes mellitus population was simultaneously studied. There were no significant relationships between the levels of periodontal disease and the duration of diabetes, the type of treatment and the frequency of systemic complications. Periodontal disease in the diabetic appeared to the affected by the same etiologic factors [plaque, calculus, neglect] as would be expected in nondiabetic patients. Further studies with larger population samples would be appropriate.

  2. Testosterone and Aggression.

    ERIC Educational Resources Information Center

    Archer, John

    1994-01-01

    Studies comparing aggressive and nonaggressive prisoners show higher testosterone levels among the former. While there is limited evidence for a strong association between aggressiveness and testosterone during adolescence, other studies indicate that testosterone levels are responsive to influences from the social environment, particularly those…

  3. Social Aggression among Girls.

    ERIC Educational Resources Information Center

    Underwood, Marion K.

    Noting recent interest in girls' social or "relational" aggression, this volume offers a balanced, scholarly analysis of scientific knowledge in this area. The book integrates current research on emotion regulation, gender, and peer relations, to examine how girls are socialized to experience and express anger and aggression from infancy…

  4. Neuropsychiatry of Aggression

    PubMed Central

    Lane, Scott D.; Kjome, Kimberly L.; Moeller, F. Gerard

    2010-01-01

    Synopsis Aggression is a serious medical problem that can place both the patient and the health care provider at risk. Aggression can result from medical, neurologic and or psychiatric disorders. A comprehensive patient evaluation is needed. Treatment options include pharmacotherapy as well as non-pharmacologic interventions, both need to be individualized to the patient. PMID:21172570

  5. Humor, Aggression, and Aging.

    ERIC Educational Resources Information Center

    Barrick, Ann Louise; And Others

    Although humor is an important phenomenon in human interactions, it has rarely been studied in the elderly. An understanding of responses to humor in aggressive cartoons as a function of advancing age would provide information regarding both the development of humor and the negative (aggressive) emotional experiences of the elderly. This study was…

  6. Serotonin and Aggression.

    ERIC Educational Resources Information Center

    Brown, Serena-Lynn; And Others

    1994-01-01

    Decreased serotonin function has consistently been shown to be highly correlated with impulsive aggression across a number of different experimental paradigms. Such lowered serotonergic indices appear to correlate with the dimension of aggression dyscontrol and/or impulsivity rather than with psychiatric diagnostic categories per se. Implications…

  7. Large-Scale Advanced Prop-Fan (LAP) blade design

    NASA Technical Reports Server (NTRS)

    Violette, John A.; Sullivan, William E.; Turnberg, Jay E.

    1984-01-01

    This report covers the design analysis of a very thin, highly swept, propeller blade to be used in the Large-Scale Advanced Prop-Fan (LAP) test program. The report includes: design requirements and goals, a description of the blade configuration which meets requirements, a description of the analytical methods utilized/developed to demonstrate compliance with the requirements, and the results of these analyses. The methods described include: finite element modeling, predicted aerodynamic loads and their application to the blade, steady state and vibratory response analyses, blade resonant frequencies and mode shapes, bird impact analysis, and predictions of stalled and unstalled flutter phenomena. Summarized results include deflections, retention loads, stress/strength comparisons, foreign object damage resistance, resonant frequencies and critical speed margins, resonant vibratory mode shapes, calculated boundaries of stalled and unstalled flutter, and aerodynamic and acoustic performance calculations.

  8. Volatile compounds in fruits of Peucedanum cervaria (Lap.) L.

    PubMed

    Skalicka-Wozniak, Krystyna; Los, Renata; Glowniak, Kazimierz; Malm, Anna

    2009-07-01

    The volatile compounds from Peucedanum cervaria (Lap.) L. were obtained by hydrodistillation (HD) and headspace solid-phase microextraction techniques (HS-SPME), and then analyzed by GC/MS methods. The composition of samples from a botanical garden was compared with plants collected in the wild. The main compounds of the essential oils of P. cervaria were identified as alpha-pinene, sabinene, and beta-pinene (more than 80% of oil). The content of beta-myrcene, limonene+beta-phellandrene, and germacrene D was higher than 1%. The in vitro antibacterial activity of the essential oil was evaluated by the agar dilution method against ten reference strains of Gram-positive and Gram-negative bacteria.

  9. Fatigue strength of a single lap joint SPR-bonded

    NASA Astrophysics Data System (ADS)

    Di Franco, G.; Fratini, L.; Pasta, A.

    2011-05-01

    In the last years, hybrid joints, meaning with this the joints which consist in combining a traditional mechanical joint to a layer of adhesive, are gradually attracting the attention of various sectors of the construction of vehicles and transportation industries, for their better performance compared to just mechanical joints (self-piercing riveting SPR, riveting, and so on) or just to bonded joints. The paper investigates the fatigue behavior of a single lap joint self-piercing riveted (SPR) and bonded throughout fatigue tests. The considered geometric configuration allowed the use of two rivets placed longitudinally; an epoxy resin was used as adhesive. In the first part of the work static characterization of the joints was carried out through tensile tests. Then fatigue tests were made with the application of different levels of load. The fatigue curves were also obtained at the varying the distance between the two rivets in order to better assess the joint strength for a given length of overlap.

  10. Testing composite-to-metal tubular lap joints

    SciTech Connect

    Guess, T.R.; Reedy, E.D. Jr.; Slavin, A.M.

    1993-11-01

    Procedures were developed to fabricate, nondestructively evaluate, and mechanically test composite-to-metal tubular joints. The axially loaded tubular lap joint specimen consisted of two metal tubes bonded within each end of a fiberglass composite tube. Joint specimens with both tapered and untapered aluminum adherends and a plain weave E-glass/epoxy composite were tested in tension, compression, and flexure. Other specimens with tapered and untapered steel adherends and a triaxially reinforced E-glass/epoxy composite were tested in tension and compression. Test results include joint strength and failure mode data. A finite element analysis of the axially loaded joints explains the effect of adherend geometry and material properties on measured joint strength. The flexural specimen was also analyzed; calculated surface strains are in good agreement with measured values, and joint failure occurs in the region of calculated peak peel stress.

  11. How dogs lap: ingestion and intraoral transport in Canis familiaris.

    PubMed

    Crompton, A W; Musinsky, Catherine

    2011-12-23

    It has recently been suggested that the mechanism for lifting liquid from a bowl into the oral cavity during lapping is fundamentally different in cats and dogs: cats use adhesion of liquid to the tongue tip while dogs 'scoop' with their backwardly curled tongue. High-speed light videos and X-ray videos show that on the contrary, both cats and dogs use the mechanism of adhesion. Liquid is transported through the oral cavity to the oesophagus, against gravity, on the surface of the tongue as it is drawn upwards, then a tight contact between the tongue surface and palatal rugae traps liquid and prevents its falling out as the tongue is protruded. At least three cycles are needed for intraoral transport of liquid in the dog.

  12. Mammalian Toxicological Evaluation of TNT Wastewaters. Volume II. Acute and Subacute Mammalian Toxicity of TNT and LAP Mixture

    DTIC Science & Technology

    1979-06-01

    synthesis assay ; UDS assay . 20 ABSTRACT (Continued) ,LAP and LAP(I) produced conjunctivitis, iritis, and/or corneal opacity In rabbit eyes; the...and 0.38 (mildly irritating) for LAP(I). j j: In the maximization ,egt, LAP ane LAP(I) produced mild reactions in 67 and 70%, respectively, of the sites...of guinea pigs challenged with the material; these •alues classify both as strong allergens. "’In in vitro microbial assays using microsomal

  13. Secondary bending effects in progressively damaged single-lap, single-bolt composite joints

    NASA Astrophysics Data System (ADS)

    Zhao, Libin; Xin, An; Liu, Fengrui; Zhang, Jianyu; Hu, Ning

    Static tensile experiments and progressive failure simulations of single-bolt, single- and double-lap joints were carried out to comparatively investigate secondary bending effects, which present significant eccentric-loading phenomena in single-lap joints but are almost non-existent in symmetric double-lap joints. Progressive damage models of single-lap and double-lap joints were established, from which the numerical predictions were found to be in good agreement with the experimental outcomes. Experimental macro-scope failure patterns and seven numerical micro-scope failure modes obtained from the progressive damage analyses were presented for the two types of joints. The effects of secondary bending on the mechanical degradation and failure mechanism of single-lap joints were revealed. Some characterizations of secondary bending in the joints, such as a characterized parameter on the AGARD points, joint deformations and contact states, were quantitatively traced during the total progressive damage process. All these characterizations increased the understanding of the effects of secondary bending on the failure process of a single-bolt, single-lap joint.

  14. Gene polymorphism of β-defensin-1 is associated with susceptibility to periodontitis in Japanese.

    PubMed

    Ikuta, Takahisa; Inagaki, Yuji; Tanaka, Kazuya; Saito, Tsuyoshi; Nakajima, Yukiko; Bando, Mika; Kido, Jun-Ichi; Nagata, Toshihiko

    2015-01-01

    Periodontitis is a multifactorial disease associated with genetic and environmental factors. Single-nucleotide polymorphisms (SNPs) are associated with susceptibility to common diseases such as diabetes and periodontitis. Although the oral cavity is exposed to various organisms, the conditions are well controlled by innate and acquired immune systems. Antimicrobial peptides (AMPs) play an important role in the innate immune system; however, the association of AMP-SNPs with periodontitis has not been fully elucidated. This study investigated the relationship between AMP-SNPs and periodontitis in Japanese. One hundred and five Japanese subjects were recruited, which included patients with aggressive, severe, moderate and mild periodontitis, and age-matched healthy controls. Genomic DNA was isolated from peripheral blood and genotypes of SNPs of β-defensin-1 and lactoferrin genes (DEFB1: rs1799946, rs1800972 and rs11362; and LTF: rs1126478) were investigated using the PCR-Invader assay. Protein level of AMPs in gingival crevicular fluid (GCF) was quantified by ELISA. Case-control studies revealed that the -44 CC genotype of DEFB1 (rs1800972) was associated with periodontitis (OR 2.51), particularly with severe chronic periodontitis (OR 4.15) and with combined severe and moderate chronic periodontitis (OR 4.04). No statistical differences were found in other genotypes. The β-defensin-1 concentrations in GCF were significantly lower in subjects with the -44 CC genotype of DEFB1 than in those without this genotype. No significant differences between GCF concentrations of AMPs and other genotypes were detected. The -44 CC genotype of the β-defensin-1 gene (DEFB1 rs1800972) may be associated with susceptibility to chronic periodontitis in Japanese.

  15. Mechanisms Involved in the Association between Periodontitis and Complications in Pregnancy

    PubMed Central

    Zi, Marcela Yang Hui; Longo, Priscila Larcher; Bueno-Silva, Bruno; Mayer, Marcia Pinto Alves

    2015-01-01

    The association between periodontitis and some of the problems with pregnancy such as premature delivery, low weight at birth, and preeclampsia (PE) has been suggested. Nevertheless, epidemiological data have shown contradictory data, mainly due to differences in clinical parameters of periodontitis assessment. Furthermore, differences in microbial composition and immune response between aggressive and chronic periodontitis are not addressed by these epidemiological studies. We aimed to review the current data on the association between some of these problems with pregnancy and periodontitis, and the mechanisms underlying this association. Shifts in the microbial composition of the subgingival biofilm may occur during pregnancy, leading to a potentially more hazardous microbial community. Pregnancy is characterized by physiological immune tolerance. However, the infection leads to a shift in maternal immune response to a pathogenic pro-inflammatory response, with production of inflammatory cytokines and toxic products. In women with periodontitis, the infected periodontal tissues may act as reservoirs of bacteria and their products that can disseminate to the fetus-placenta unit. In severe periodontitis patients, the infection agents and their products are able to activate inflammatory signaling pathways locally and in extra-oral sites, including the placenta-fetal unit, which may not only induce preterm labor but also lead to PE and restrict intrauterine growth. Despite these evidences, the effectiveness of periodontal treatment in preventing gestational complications was still not established since it may be influenced by several factors such as severity of disease, composition of microbial community, treatment strategy, and period of treatment throughout pregnancy. This lack of scientific evidence does not exclude the need to control infection and inflammation in periodontitis patients during pregnancy, and treatment protocols should be validated. PMID:25688342

  16. The influence of diabetes mellitus on periodontal tissues: a pilot study

    PubMed Central

    Um, Yoo-Jung; Jung, Ui-Won; Kim, Chang-Sung; Bak, Eun-Jung; Cha, Jeong-Heon; Yoo, Yun-Jung

    2010-01-01

    Purpose The purpose of this study was to preliminarily evaluate the influence of diabetes mellitus (DM) on periodontal tissue without establishment of periodontitis. Methods Seven-week-old db/db mice were used for the diabetic experimental group and systematically healthy mice of the same age were used as controls. After 1 week of acclimatization, the animals were sacrificed for hard and soft tissue evaluation. The pattern of bone destruction was evaluated by stereomicroscope evaluation with alizarin red staining and radiographic evaluation by microscopic computerized tomography images. Histological evaluation was performed with hematoxylin and eosin stain for evaluation of soft tissue changes. Results In both stereomicroscope evaluation and radiograph image analysis, aggressive form of bone destruction was observed in diabetic animals when compared to the systematically healthy controls. In histological evaluation, apical migration of junctional epithelium with slight inflammatory cell infiltration was observed with disarrangement of connective tissue fibers. Conclusions Within the limits of this study, diabetic animals presented distortion in periodontal attachment and an aggressive bone loss pattern when compared to the healthy controls, suggesting that DM has an independent effect on periodontal tissue destruction irrespective of the presence or absence of periodontal disease. PMID:20498760

  17. Regenerative periodontal therapy.

    PubMed

    Kao, Daniel W K; Fiorellini, Joseph P

    2012-01-01

    Traditional treatment for loss of bone and attachment due to periodontal disease has focused around repairing the damage induced. However, over the past few decades, clinicians have begun to utilize regenerative techniques to rebuild bone, cementum and the periodontal ligament. Conventional procedures most often involve the use of barrier membranes with bone grafts that foster selective cell repopulation and regrowth of osseous structures. Since the predictability of these techniques may be limited to certain case types, pharmacologically based efforts are underway to investigate the possibility of harnessing osseous regrowth potential. Clinical research has found that proteins are potent biological mediators that promote many of the events in wound healing, and have been shown to promote bone formation in human clinical studies.

  18. Laser therapy for periodontitis

    NASA Astrophysics Data System (ADS)

    Efanov, O. I.

    2001-04-01

    An investigation was made of applying pulsed (lambda) equals 0.89 micrometers laser radiation in the treatment for early diagnosed periodontitis. The investigation was made on 65 patients (47 patients constituted the experimental group and 18 patients constituted a control group) affected by periodontitis. Clinical and functional tests revealed that laser therapy produced a string effect on the course of the illness. It reduced bleeding, inflammation, and pruritus. However, it did not produce an affect on electroexcitation. Biomicroscopic examinations and periodontium rheography revealed that the gingival blood flow became normal after the course of laser therapy. The capillary permeability and venous congestion decreased, which was confirmed by the increased time of vacuum tests, raised gingival temperature, reduced tissue clearance, and increased oxygen tension. Apart from that, laser therapy subsided fibrinolysis, proteolytic tissue activity, and decreased the exudative inflammation of periodontium.

  19. Lasers in periodontics

    PubMed Central

    Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie

    2012-01-01

    Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20th century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics. PMID:23066266

  20. The Role of Activated Cytotoxic T Cells in Etiopathogenesis of Periodontal Disease: Does It Harm or Does It Heal?

    PubMed Central

    Cifcibasi, Emine; Ciblak, Meral; Kiran, Bayram; Badur, Selim; Firatli, Erhan; Issever, Halim; Cintan, Serdar

    2015-01-01

    The objective of this study was to determine the phenotypic profile of blood mononuclear cells, specifically CD8+/CD28+ cells, in patients with generalized aggressive periodontitis (GAgP) and chronic periodontitis (CP) in peripheral blood and in blood obtained from periodontal defect site which might contribute to tissue damage. 13 GAgP, 11 chronic periodontitis (CP) and 5 healthy controls (H) were included in the study. Plaque index (PI), bleeding on probing (BoP), periodontal probing depth (PPD) and clinical attachment level (CAL) were recorded. Blood from the base of periodontal defect site and peripheral blood from the antecubital vein were obtained. Relative counts of CD45+, CD3+, CD4+, CD8+/CD28+, CD8+/CD28−, CD19+, CD16+/CD56+/CD3, CD3+/CD16+/CD56+ receptors were determined with two color flow cytometry using monoclonal antibodies. BoP, PPD and CAL were significantly higher in both periodontitis groups than healthy controls (p <0.05). Activated cytotoxic T cells, CD8+/CD28+ cells, were significantly elevated in GAgP and CP groups compared to HC both in blood obtained from defect site and blood obtained from systemic circulation (p <0.05). GAgP and CP patients have an increased levels of activated cytotoxic T cells as a result of inflammation which may cause severe tissue damage that lead to severe and rapid loss of periodontal tissues. PMID:25788457

  1. Gene therapy in periodontics.

    PubMed

    Chatterjee, Anirban; Singh, Nidhi; Saluja, Mini

    2013-03-01

    GENES are made of DNA - the code of life. They are made up of two types of base pair from different number of hydrogen bonds AT, GC which can be turned into instruction. Everyone inherits genes from their parents and passes them on in turn to their children. Every person's genes are different, and the changes in sequence determine the inherited differences between each of us. Some changes, usually in a single gene, may cause serious diseases. Gene therapy is 'the use of genes as medicine'. It involves the transfer of a therapeutic or working gene copy into specific cells of an individual in order to repair a faulty gene copy. Thus it may be used to replace a faulty gene, or to introduce a new gene whose function is to cure or to favorably modify the clinical course of a condition. It has a promising era in the field of periodontics. Gene therapy has been used as a mode of tissue engineering in periodontics. The tissue engineering approach reconstructs the natural target tissue by combining four elements namely: Scaffold, signaling molecules, cells and blood supply and thus can help in the reconstruction of damaged periodontium including cementum, gingival, periodontal ligament and bone.

  2. Use of two-dimensional transmission photoelastic models to study stresses in double-lap bolted joints

    NASA Technical Reports Server (NTRS)

    Hyer, M. W.; Liu, D. H.

    1981-01-01

    The stress distribution in two hole connectors in a double lap joint configuration was studied. The following steps are described: (1) fabrication of photoelastic models of double lap double hole joints designed to determine the stresses in the inner lap; (2) assessment of the effects of joint geometry on the stresses in the inner lap; and (3) quantification of differences in the stresses near the two holes. The two holes were on the centerline of the joint and the joints were loaded in tension, parallel to the centerline. Acrylic slip fit pins through the holes served as fasteners. Two dimensional transmission photoelastic models were fabricated by using transparent acrylic outer laps and a photoelastic model material for the inner laps. It is concluded that the photoelastic fringe patterns which are visible when the models are loaded are due almost entirely to stresses in the inner lap.

  3. The effect of diamond powder characteristics on lapping of sintered silicon carbide

    NASA Astrophysics Data System (ADS)

    Rosczyk, Benjamin; Burkam, Eric; Titov, Artem; Onyenemezu, Clement; Benea, Ion C.

    2015-10-01

    In Automotive applications, sintered Silicon Carbide has been used in applications such as seal pump faces. The surface of sintered SiC, when lapped or polished for sealing to another surface, must be free of blemishes and mechanical defects. Lapping and polishing processes therefore must be well defined and controlled assuring minimal variation and production scrap. In this study, we related the characteristics of different diamond powders (particle size distribution, particle shape and surface) to their performance in lapping of sintered silicon carbide material, expressed as removal rate and surface finish.

  4. Machine imparting complex rotary motion for lapping a spherical inner diameter

    DOEpatents

    Carroll, Thomas A.; Yetter, Harold H.

    1986-01-01

    An apparatus for imparting complex rotary motion is used to lap an inner spherical diameter surface of a workpiece. A lapping tool consists of a dome and rod mounted along the dome's vertical axis. The workpiece containing the lapping tool is held in a gimbal which uses power derived from a secondary takeoff means to impart rotary motion about a horizontal axis. The gimbal is rotated about a vertical axis by a take means while mounted at a radially outward position on a rotating arm.

  5. Machine imparting complex rotary motion for lapping a spherical inner diameter

    DOEpatents

    Carroll, T.A.; Yetter, H.H.

    1985-01-30

    An apparatus for imparting complex rotary motion is used to lap an inner spherical diameter surface of a workpiece. A lapping tool consists of a dome and rod mounted along the dome's vertical axis. The workpiece containing the lapping tool is held in a gimbal which uses power derived from a secondary takeoff means to impart rotary motion about a horizontal axis. The gimbal is rotated about a vertical axis by a take means while mounted at a radially outward position on a rotating arm.

  6. Global-Local Finite Element Analysis of Bonded Single-Lap Joints

    NASA Technical Reports Server (NTRS)

    Kilic, Bahattin; Madenci, Erdogan; Ambur, Damodar R.

    2004-01-01

    Adhesively bonded lap joints involve dissimilar material junctions and sharp changes in geometry, possibly leading to premature failure. Although the finite element method is well suited to model the bonded lap joints, traditional finite elements are incapable of correctly resolving the stress state at junctions of dissimilar materials because of the unbounded nature of the stresses. In order to facilitate the use of bonded lap joints in future structures, this study presents a finite element technique utilizing a global (special) element coupled with traditional elements. The global element includes the singular behavior at the junction of dissimilar materials with or without traction-free surfaces.

  7. Bone Morphogenetic Proteins: Periodontal Regeneration

    PubMed Central

    Rao, Subramaniam M; Ugale, Gauri M; Warad, Shivaraj B

    2013-01-01

    Periodontitis is an infectious inflammatory disease that results in attachment loss and bone loss. Regeneration of the periodontal tissues entails de novo formation of cementum, periodontal ligament, and alveolar bone. Several different approaches are currently being explored to achieve complete, reliable, and reproducible regeneration of periodontal tissues. The therapeutic management of new bone formation is one of the key issues in successful periodontal regeneration. Bone morphogenetic proteins form a unique group of proteins within the transforming growth factor superfamily of genes and have a vital role in the regulation in the bone induction and maintenance. The activity of bone morphogenetic proteins was first identified in the 1960s, but the proteins responsible for bone induction were unknown until the purification and cloning of human bone morphogenetic proteins in the 1980s, because of their osteoinductive potential. Bone morphogenetic proteins have gained a lot of interest as therapeutic agents for treating periodontal defects. A systematic search for data related to the use of bone morphogenetic proteins for the regeneration of periodontal defects was performed to recognize studies on animals and human (PUBMED, MEDLINE, COCHRANE, and Google search). All the studies included showed noticeable regeneration of periodontal tissues with the use of BMP. PMID:23626951

  8. Aggression and sport.

    PubMed

    Burton, Robert W

    2005-10-01

    Viewing aggression in its healthy form, in contrast to its extreme and inappropriate versions, and sport as a health-promoting exercise in psychological development and maturation may allow participants and spectators alike to retain an interest in aggression and sport and derive further enjoyment from them. In addition, it will benefit all involved with sport to have a broader understanding of human aggression. Physicians, mental health professionals, and other health care providers can be influential in this process, and should be willing to get involved and speak out when issues and problems arise.

  9. Periodontal Dressing: A Review Article

    PubMed Central

    Baghani, Zahra; Kadkhodazadeh, Mahdi

    2013-01-01

    The purpose of this paper was to review the commercially available periodontal dressings, their physical and chemical properties, biocompatibility and therapeutic effects. Electronic search of scientific papers from 1956 to 2012 was carried out using PubMed, Scopus and Wiley InterScience search engines using the searched terms periodontal dressing, periodontal pack. Numerous in vitro and in vivo studies have evaluated various properties of periodontal dressings. Physical and chemical properties of dressings are directly related to their dimensional changes and adhesion properties. Their biocompatibility and therapeutic effect are among the other factors evaluated in the literature. Chlorhexidine is the most commonly used antibacterial agent in studies. In general, when comparing the advantages with the disadvantages, application of periodontal dressing seems to be beneficial. Numerous factors are involved in selection of an optimal dressing such as surgeon’s intention, required time for the dressing to remain on the surgery site and its dimensional changes. PMID:24578815

  10. [Treatment of localized intrabony periodontal defects with enamel matrix derivative (Emdogain). Case series].

    PubMed

    Szatmári, Péter; Gera, István

    2014-03-01

    The solitary vertical or horisonto-vertical bone lesions are mainly characteristic of aggressive periodontitis. Only a combined conservative-surgical approach can result in predictable healing. From the early 50's basically two surgical techniques were used for correcting vertical bony defects. The so called bone resective techniques combined with apically positioned flap resulted in the flattening of the bone contour by removing substantial amount of alveolar bone but compromising the periodontal support of the neighboring teeth. The other surgical approach was the facilitation of the reformation of new periodontal attachment and bone with or without bone grafting. Since the mid 80's the gold standard in the therapy of deep vertical bony defects is the guided tissue regeneration (GTR), although an alternative approach has also been developed using different growth and differentiation factors promoting periodontal wound healing. Today in the clinical practices both in periodontal osseous and mucogingival surgeries the most widely used biological factor is the amelogenin and its commercially available product the Enamel Matrix Derivative (Emdogain). With the presented five solitary horisonto-vertical bony defects of three patients the possibilities and the late results are presented that could have been achieved with the application of EMD and thorough postoperative follow-up. The clinical results were comparable to the current data presented by articles in peer reviewed periodontal journals.

  11. A characterization of the LAP Aquarius Phantom for external LAP laser alignment and magnetic resonance geometric distortion verification for stereotactic radiation surgery patient simulation

    NASA Astrophysics Data System (ADS)

    Vergara, Daniel

    The Thesis explores additional applications of LAP's Aquarius external laser alignment verification Phantom by examining geometric accuracy of magnetic resonance images commonly used for planning intracranial stereotactic radiation surgery (ICSRS) cases. The scans were performed with MRI protocols used for ICSRS, and head and neck diagnosis, and their images fused to computerized tomographic (CT) images. The geometric distortions (GDs) were measured against the CT in all axial, sagittal, and coronal directions at different levels. Using the Aquarius Phantom, one is able to detect GD in ICSRS planning MRI acquisitions, and align the external LAP patient alignment lasers, by following the LAP QA protocol. GDs up to about 2 mm are observed at the distal regions of the longitudinal axis in the SRS treatment planning MR images. Based on the results, one may recommend the use of the Aquarius Phantom to determine if margins should be included for SRS treatment planning.

  12. Alteration of Sulphides in the Rumuruti Chondrite La Paz Icefield (LAP) 031275

    NASA Astrophysics Data System (ADS)

    Steer, E. D.; Treiman, A. H.

    2014-09-01

    Pyrrhotite in LAP 03175 (R5) has altered to a fine-grained mineral mixture. New data (optical, chemical, and Raman) suggest the mixture includes violarite and tochilinite, but not (as suggested earlier) graphite, hematite, and/or jarosite.

  13. Aggression in Pretend Play and Aggressive Behavior in the Classroom

    ERIC Educational Resources Information Center

    Fehr, Karla K.; Russ, Sandra W.

    2013-01-01

    Research Findings: Pretend play is an essential part of child development and adjustment. However, parents, teachers, and researchers debate the function of aggression in pretend play. Different models of aggression predict that the expression of aggression in play could either increase or decrease actual aggressive behavior. The current study…

  14. Crystal structure, spectroscopic and thermal properties of [Zn(Lap)2(DMF)(H2O)] and isomorphous [M(Lap)2]n (M: Cd, Mn) complexes

    NASA Astrophysics Data System (ADS)

    Farfán, R. A.; Espíndola, J. A.; Gomez, M. I.; de Jiménez, M. C. L.; Piro, O. E.; Castellano, E. E.; Martínez, M. A.

    2015-05-01

    The solid state structure of the lapacholate (Lap-) complexes with Zn(II), Cd(II) and Mn(II) were determined by X-ray diffraction methods. [Zn(Lap)2(DMF)(H2O)] crystallizes in the triclinic space group P 1 bar with a = 10.5051(4), b = 12.8020(4), c = 13.0394(4) Å, α = 60.418(2), β = 83.904(2), γ = 86.206(2)°, and Z = 2 molecules per unit cell. The isomorphous complexes [M(Lap)2]n (M: Cd, Mn) crystallize in the tetragonal space group P43212 with a = b = 13.5770(6) Å, c = 14.5730(6) Å (Cd), and a = b = 13.3539(4), c = 14.7148(4) Å (Mn), and Z = 4. In [Zn(Lap)2(DMF)(H2O)] the Zn(II) ion is in a distorted octahedral environment coordinated to two different and nearly perpendicular Lap- molecules acting as bidentate ligands through their adjacent carbonyl and phenol oxygen atoms. The remaining two cis-coordination sites are occupied by water and DMF molecules. [M(Lap)2]n (M: Cd, Mn) isomorphous complexes are also octahedral and present a supra-molecular arrangement in the lattice. There is only one independent Lap- molecule that coordinates the metal through all three ligand binding sites, giving rise to a 3-D structure of [M(Lap)2]n complexes that extends throughout the crystal lattice. The lapachol binding to metal is also revealed by the IR spectra. In fact, the carbonyl Cdbnd O stretching frequency is appreciable red-shifted in the complexes as compared to uncoordinated lapachol ligand. As expected, the IR and UV-Vis spectra of the isomorphous pair of complexes closely resemble to each other. Up to above 300 °C there are significant differences in the TGA of the Zn complex when compared with the isomorphous pair: while the former shows the loss of the secondary ligands (water and DMF), the latter exhibits a plateau signaling the lesser labile character of the lapacholate ligand.

  15. Current concepts in periodontal bioengineering

    PubMed Central

    Taba, M.; Jin, Q.; Sugai, J.V.; Giannobile, W.V.

    2008-01-01

    Repair of tooth supporting alveolar bone defects caused by periodontal and peri-implant tissue destruction is a major goal of reconstructive therapy. Oral and craniofacial tissue engineering has been achieved with limited success by the utilization of a variety of approaches such as cell-occlusive barrier membranes, bone substitutes and autogenous block grafting techniques. Signaling molecules such as growth factors have been used to restore lost tooth support because of damage by periodontal disease or trauma. This paper will review emerging periodontal therapies in the areas of materials science, growth factor biology and cell/gene therapy. Several different polymer delivery systems that aid in the targeting of proteins, genes and cells to periodontal and peri-implant defects will be highlighted. Results from preclinical and clinical trials will be reviewed using the topical application of bone morphogenetic proteins (BMP-2 and BMP-7) and platelet-derived growth factor-BB (PDGF) for periodontal and peri-implant regeneration. The paper concludes with recent research on the use of ex vivo and in vivo gene delivery strategies via gene therapy vectors encoding growth promoting and inhibiting molecules (PDGF, BMP, noggin and others) to regenerate periodontal structures including bone, periodontal ligament and cementum. PMID:16238610

  16. Fatigue strength of a single lap joint SPR-bonded

    SciTech Connect

    Di Franco, G.; Fratini, L.; Pasta, A.

    2011-05-04

    In the last years, hybrid joints, meaning with this the joints which consist in combining a traditional mechanical joint to a layer of adhesive, are gradually attracting the attention of various sectors of the construction of vehicles and transportation industries, for their better performance compared to just mechanical joints (self-piercing riveting SPR, riveting, and so on) or just to bonded joints.The paper investigates the fatigue behavior of a single lap joint self-piercing riveted (SPR) and bonded throughout fatigue tests. The considered geometric configuration allowed the use of two rivets placed longitudinally; an epoxy resin was used as adhesive. In the first part of the work static characterization of the joints was carried out through tensile tests. Then fatigue tests were made with the application of different levels of load. The fatigue curves were also obtained at the varying the distance between the two rivets in order to better assess the joint strength for a given length of overlap.

  17. Molten pool characterization of laser lap welded copper and aluminum

    NASA Astrophysics Data System (ADS)

    Xue, Zhiqing; Hu, Shengsun; Zuo, Di; Cai, Wayne; Lee, Dongkyun; Elijah, Kannatey-Asibu, Jr.

    2013-12-01

    A 3D finite volume simulation model for laser welding of a Cu-Al lap joint was developed using ANSYS FLUENT to predict the weld pool temperature distribution, velocity field, geometry, alloying element distribution and transition layer thickness—all key attributes and performance characteristics for a laser-welded joint. Melting and solidification of the weld pool was simulated with an enthalpy-porosity formulation. Laser welding experiments and metallographic examination by SEM and EDX were performed to investigate the weld pool features and validate the simulated results. A bowl-shaped temperature field and molten pool, and a unique maximum fusion zone width were observed near the Cu-Al interface. Both the numerical simulation and experimental results indicate an arch-shaped intermediate layer of Cu and Al, and a gradual transition of Cu concentration from the aluminum plate to the copper plate with high composition gradient. For the conditions used, welding with Cu on top was found to result in a better weld joint.

  18. Orthodontic-periodontics interdisciplinary approach.

    PubMed

    Vinod, K; Reddy, Y Giridhar; Reddy, Vinay P; Nandan, Hemant; Sharma, Meenakshi

    2012-01-01

    In this present era, when a significant number of patients seeking orthodontic treatment are adults, importance of multidisciplinary treatment approach cannot be overemphasized. Higher susceptibility of plaque accumulation in patients undergoing orthodontic treatment makes involvement of periodontist almost unavoidable. Also, orthodontic treatment frequently results in undesirable periodontal changes which require immediate attention. More recently, orthodontics has been used as an adjunct to periodontics to increase connective tissue support and alveolar bone height. The purpose of this article is to review the adverse effects of orthodontic treatment on the periodontal tissues and to discuss the mutually beneficial relationship shared between the two specialties.

  19. Orthodontic–periodontics interdisciplinary approach

    PubMed Central

    Vinod, K.; Reddy, Y. Giridhar; Reddy, Vinay P.; Nandan, Hemant; Sharma, Meenakshi

    2012-01-01

    In this present era, when a significant number of patients seeking orthodontic treatment are adults, importance of multidisciplinary treatment approach cannot be overemphasized. Higher susceptibility of plaque accumulation in patients undergoing orthodontic treatment makes involvement of periodontist almost unavoidable. Also, orthodontic treatment frequently results in undesirable periodontal changes which require immediate attention. More recently, orthodontics has been used as an adjunct to periodontics to increase connective tissue support and alveolar bone height. The purpose of this article is to review the adverse effects of orthodontic treatment on the periodontal tissues and to discuss the mutually beneficial relationship shared between the two specialties. PMID:22628956

  20. Periodontal disease's contribution to Alzheimer's disease progression in Down syndrome.

    PubMed

    Kamer, Angela R; Fortea, Juan O; Videla, Sebastià; Mayoral, Angela; Janal, Malvin; Carmona-Iragui, Maria; Benejam, Bessy; Craig, Ronald G; Saxena, Deepak; Corby, Patricia; Glodzik, Lidia; Annam, Kumar Raghava Chowdary; Robbins, Miriam; de Leon, Mony J

    2016-01-01

    People with Down syndrome (DS) are at an increased risk for Alzheimer's disease (AD). After 60 years of age, >50% of DS subjects acquire dementia. Nevertheless, the age of onset is highly variable possibly because of both genetic and environmental factors. Genetics cannot be modified, but environmental risk factors present a potentially relevant intervention for DS persons at risk for AD. Among them, inflammation, important in AD of DS type, is potential target. Consistent with this hypothesis, chronic peripheral inflammation and infections may contribute to AD pathogenesis in DS. People with DS have an aggressive form of periodontitis characterized by rapid progression, significant bacterial and inflammatory burden, and an onset as early as 6 years of age. This review offers a hypothetical mechanistic link between periodontitis and AD in the DS population. Because periodontitis is a treatable condition, it may be a readily modifiable risk factor for AD.

  1. Relationship between diabetes and periodontal infection

    PubMed Central

    Llambés, Fernando; Arias-Herrera, Santiago; Caffesse, Raúl

    2015-01-01

    Periodontal disease is a high prevalent disease. In the United States 47.2% of adults ≥ 30 years old have been diagnosed with some type of periodontitis. Longitudinal studies have demonstrated a two-way relationship between diabetes and periodontitis, with more severe periodontal tissue destruction in diabetic patients and poorer glycemic control in diabetic subjects with periodontal disease. Periodontal treatment can be successful in diabetic patients. Short term effects of periodontal treatment are similar in diabetic patients and healthy population but, more recurrence of periodontal disease can be expected in no well controlled diabetic individuals. However, effects of periodontitis and its treatment on diabetes metabolic control are not clearly defined and results of the studies remain controversial. PMID:26185600

  2. Periodontal disease: an overview for physicians.

    PubMed

    Fenesy, K E

    1998-01-01

    Periodontitis is now seen as resulting from a complex interplay of bacterial infection and host response, often modified by behavioral factors. There has been a fundamental change in the prevailing periodontal disease model of the 1960s, which suggested that the susceptibility to periodontitis increases with age, and that all individuals are susceptible to severe periodontal disease. More recent research has changed the belief in universal susceptibility to the current view that only some 5-20% of any population suffer from severe generalized periodontitis, and that only moderate disease affects a majority of adults. One major risk factor is smoking, as there is now a clear association between smoking and periodontal disease independent of oral hygiene, age, or any other risk factor. In human periodontitis, there is no simple, direct pathogen-disease link. There are three pathogens that have a strong association with progressive periodontal disease: Actinobacillus actinomycetemcomitans, spirochetes of acute necrotizing gingivitis, and Porphyromonas gingivalis. These pathogens may be the cause of continued loss of periodontal attachment in all periodontal disease classifications despite diligent periodontal therapy. This loss of attachment, or destruction of the periodontal ligament and loss of adjacent supporting bone, is seen in adult periodontitis, as well as in early-onset periodontitis, which affects young persons who otherwise appear healthy. The three forms of early-onset periodontitis are prepubertal periodontitis, localized and generalized juvenile periodontitis, and rapidly progressive periodontitis. They are distinguished from adult periodontitis by the age of onset of the disease, the rapid rate of disease progression, manifestations of defects in host response, and the composition of the subgingival microflora. Prepubertal periodontitis is associated with attachment loss around teeth of the deciduous and/or permanent dentition, and is often associated

  3. Surgical and nonsurgical periodontal therapy. Learned and unlearned concepts.

    PubMed

    Heitz-Mayfield, Lisa J A; Lang, Niklaus P

    2013-06-01

    This review aims to highlight concepts relating to nonsurgical and surgical periodontal therapy, which have been learned and unlearned over the past few decades. A number of treatment procedures, such as gingival curettage and aggressive removal of contaminated root cementum, have been unlearned. Advances in technology have resulted in the introduction of a range of new methods for use in nonsurgical periodontal therapy, including machine-driven instruments, lasers, antimicrobial photodynamic therapy and local antimicrobial-delivery devices. However, these methods have not been shown to offer significant benefits over and above nonsurgical debridement using hand instruments. The method of debridement is therefore largely dependent on the preferences of the operator and the patient. Recent evidence indicates that specific systemic antimicrobials may be indicated for use as adjuncts to nonsurgical debridement in patients with advanced disease. Full-mouth disinfection protocols have been proven to be a relevant treatment option. We have learned that while nonsurgical and surgical methods result in similar long-term treatment outcomes, surgical therapy results in greater probing-depth reduction and clinical attachment gain in initially deep pockets. The surgical technique chosen seems to have limited influence upon changes in clinical attachment gain. What has not changed is the importance of thorough mechanical debridement and optimal plaque control for successful nonsurgical and surgical periodontal therapy.

  4. Using risk assessment in periodontics.

    PubMed

    Woodman, Alan J

    2014-08-01

    Risk assessment has become a regular feature in both dental practice and society as a whole, and principles used to assess risk in society are similar to those used in a clinical setting. Although the concept of risk assessment as a prognostic indicator for periodontal disease incidence and activity is well established in the management of periodontitis, the use of risk assessment to manage the practical treatment of periodontitis and its sequelae appears to have less foundation. A simple system of initial risk assessment - building on the use of the Basic Periodontal Examination (BPE), clinical, medical and social factors - is described, linked to protocols for delivering care suited to general dental practice and stressing the role of long-term supportive care. The risks of not treating the patient are considered, together with the possible causes of failure, and the problems of successful treatment are illustrated by the practical management of post-treatment recession.

  5. Inquiry Teaching in Clinical Periodontics.

    ERIC Educational Resources Information Center

    Heins, Paul J.; Mackenzie, Richard S.

    1987-01-01

    An adaptation of the inquiry method of teaching, which develops skills of information retrieval and reasoning through systematic questioning by the teacher, is proposed for instruction in clinical periodontics. (MSE)

  6. Periodontal Stain Test Diagnosis Program

    DTIC Science & Technology

    1989-01-01

    inflammatory loss of attachment and bone in adolescents ; lesions are often associated with incisors and first molars; no evidence of systemic disease . RISK...FACTORS: When determining susceptibility to periodontal disease , patients in the previous classifications should be considered high risk patients if...AD-A247 28411i 11111l l l1113111! Eilli UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL PERIODONTAL STAIN TEST DIAGNOSIS PROGRAM D T IC Prof. E.J. Burkes

  7. Low-cost periodontal therapy.

    PubMed

    Slots, Jørgen

    2012-10-01

    Periodontitis is a complex infectious disease that affects low-income individuals disproportionately. Periodontitis is associated with specific bacterial species and herpesviruses, and successful prevention and treatment of the disease is contingent upon effective control of these pathogens. This article presents an efficacious, highly safe, minimally invasive, practical and low-cost periodontal therapy that involves professional and patient-administered mechanical therapy and antimicrobial agents. The major components are scaling for calculus removal, periodontal pocket irrigation with potent antiseptics, and treatment with systemic antibiotics for advanced disease. Povidone-iodine and sodium hypochlorite have all the characteristics for becoming the first-choice antiseptics in the management of periodontal diseases. Both agents show excellent antibacterial and antiviral properties, are readily available throughout the world, have been safely used in periodontal therapy for decades, offer significant benefits for individuals with very limited financial resources, and are well accepted by most dental professionals and patients. Four per cent chlorhexidine applied with a toothbrush to the most posterior part to the tongue dorsum can markedly reduce or eliminate halitosis in most individuals. Systemic antibiotics are used to treat periodontopathic bacteria that are not readily reached by topical therapy, such as pathogens within gingival tissue, within furcation defects, at the base of periodontal pockets, and on the tongue, tonsils and buccal mucosae. Valuable antibiotic therapies are amoxicillin-metronidazole (250 mg of amoxicillin and 250 mg of metronidazole, three times daily for 8 days) for young and middle-aged patients, and ciprofloxacin-metronidazole (500 mg of each, twice daily for 8 days) for elderly patients and for patients in developing countries who frequently harbor enteric rods subgingivally. Scaling to remove dental calculus and the prudent

  8. Use of lasers in periodontics.

    PubMed

    Bader, H I

    2000-10-01

    Although lasers have been used in periodontal therapy for 10 or more years, clinicians have barely begun to tap the enormous potential of this form of therapy. The relative lack of pain, ease of use, and site specificity of the laser make it an ideal addition to the periodontist's armamentarium. Applications now are being developed for a broader range of wavelengths that will offer useful, predictable, and comfortable therapy for managing the periodontal patient.

  9. Periodontitis and bone metabolism

    PubMed Central

    Barbato, Luigi; Francioni, Edoardo; Bianchi, Massimiliano; Mascitelli, Eleonora; Marco, Leila Brancato; Tonelli, Duvina Paolo

    2015-01-01

    Summary Periodontitis is a plaque induced disease characterized by tissue destruction. The extent of the alveolar bone loss depends on the host response stimulated by bacterial infection. Recently researchers have focused on the role of the immune system, of RANK/RANKL/OPG pathway and of cytokines network. Another recent field of interest is osteoimmunology that try to explain the relationship between immune and bone cells in activating bone resorption. Advances in the understanding of the pathogenic mechanisms allowed a better understanding of the relationship with other diseases like osteoporosis and also to hypothesize new therapies based on modulation of host response (host modulatory therapy - HMT). The purpose of this mini-review is to briefly discuss these topics. PMID:26604945

  10. Necrotising periodontal diseases.

    PubMed

    Bermejo-Fenoll, Ambrosio; Sánchez-Pérez, Arturo

    2004-01-01

    Necrotizing gingivitis (NG) or necrotising ulcerative gingivitis (NUG) is considered to be an acute opportunistic gingival infection caused by bacterial plaque. It appears more frequently in undernurished children and young adults as well as patients with immunodeficiency. In its pathogenesis, there are factors related to the oral microbiota with invasion processes on the one hand, and on the other hand, factors associated with the host, such as signs of capillary and immunological disorders as well as undernurishment. The disease is characterized by pain, bleeding and papillary necrosis with tendency to relapse. Diagnosis is made by a simple clinical examination. However, complementary tests ought to be performed in order to eliminate the possibility of illnesses systemic or immunodeficiency. Early and sustained treatment is strongly recommended. Lesions of the gums (craters in the interdental papillae) as an aftermath of the disease is a possibility, or if there is necrotizing periodontitis there will be loss of attachment tissue.

  11. Large-scale Advanced Prop-fan (LAP) high speed wind tunnel test report

    NASA Technical Reports Server (NTRS)

    Campbell, William A.; Wainauski, Harold S.; Arseneaux, Peter J.

    1988-01-01

    High Speed Wind Tunnel testing of the SR-7L Large Scale Advanced Prop-Fan (LAP) is reported. The LAP is a 2.74 meter (9.0 ft) diameter, 8-bladed tractor type rated for 4475 KW (6000 SHP) at 1698 rpm. It was designated and built by Hamilton Standard under contract to the NASA Lewis Research Center. The LAP employs thin swept blades to provide efficient propulsion at flight speeds up to Mach .85. Testing was conducted in the ONERA S1-MA Atmospheric Wind Tunnel in Modane, France. The test objectives were to confirm that the LAP is free from high speed classical flutter, determine the structural and aerodynamic response to angular inflow, measure blade surface pressures (static and dynamic) and evaluate the aerodynamic performance at various blade angles, rotational speeds and Mach numbers. The measured structural and aerodynamic performance of the LAP correlated well with analytical predictions thereby providing confidence in the computer prediction codes used for the design. There were no signs of classical flutter throughout all phases of the test up to and including the 0.84 maximum Mach number achieved. Steady and unsteady blade surface pressures were successfully measured for a wide range of Mach numbers, inflow angles, rotational speeds and blade angles. No barriers were discovered that would prevent proceeding with the PTA (Prop-Fan Test Assessment) Flight Test Program scheduled for early 1987.

  12. Stability of Aggressive Behavior.

    ERIC Educational Resources Information Center

    Eron, Leonard D.; Huesmann, L. Rowell

    As indicated by multiple measures (including overt criminal behavior), stability of aggressive behavior was investigated across 22 years for males and females in a variety of situations. Originally, subjects included the entire population enrolled in the third grade in a semi-rural county in New York State. The sample included approximately 870…

  13. Aggressiveness and Disobedience

    ERIC Educational Resources Information Center

    Vaaland, Grete Sorensen; Idsoe, Thormod; Roland, Erling

    2011-01-01

    This study aims to conceptualize disobedient pupil behavior within the more general framework of antisocial behavior and to reveal how two forms of aggressiveness are related to disobedience. Disobedience, in the context of this article, covers disruptive pupil behavior or discipline problems when the pupil is aware of breaking a standard set by…

  14. Intellectual Competence and Aggression.

    ERIC Educational Resources Information Center

    Huesmann, L. Rowell; Yarmel, Patty Warnick

    Using data from a broader longitudinal study, this investigation explores within-subject and cross-generational stability of intellectual competence and the relationship of such stability to aggressive behavior. Data were gathered three times (when subjects' modal age was 8, 19, and 30 years). Initially, subjects included the entire population…

  15. Relational Aggression among Students

    ERIC Educational Resources Information Center

    Young, Ellie L.; Nelson, David A.; Hottle, America B.; Warburton, Brittney; Young, Bryan K.

    2011-01-01

    "Relational aggression" refers to harm within relationships caused by covert bullying or manipulative behavior. Examples include isolating a youth from his or her group of friends (social exclusion), threatening to stop talking to a friend (the silent treatment), or spreading gossip and rumors by email. This type of bullying tends to be…

  16. Neuroimaging and Aggression.

    ERIC Educational Resources Information Center

    Mills, Shari; Raine, Adrian

    1994-01-01

    Brain imaging research allows direct assessment of structural and functional brain abnormalities, and thereby provides an improved methodology for studying neurobiological factors predisposing to violent and aggressive behavior. This paper reviews 20 brain imaging studies using four different types of neuroimaging techniques that were conducted in…

  17. Human Aggression and Suicide

    ERIC Educational Resources Information Center

    Brown, Gerald L.; Goodwin, Frederick K

    1986-01-01

    The central nervous system transmitter serontonin may be altered in aggressive/impulsive and suicidal behaviors in humans. These reports are largely consistent with animal data, and constitute one of the most highly replicated set of findings in biological psychiatry. Suggests that some suicidal behavior may be a special kind of aggressive…

  18. Leukotoxic activity of Aggregatibacter actinomycetemcomitans and periodontal attachment loss.

    PubMed

    Höglund Åberg, Carola; Haubek, Dorte; Kwamin, Francis; Johansson, Anders; Claesson, Rolf

    2014-01-01

    Aggregatibacter actinomycetemcomitans is a Gram-negative periodontitis-associated bacterium that expresses a toxin that selectively affects leukocytes. This leukotoxin is encoded by an operon belonging to the core genome of this bacterial species. Variations in the expression of the leukotoxin have been reported, and a well-characterized specific clonal type (JP2) of this bacterium with enhanced leukotoxin expression has been isolated. In particular, the presence of the JP2 genotype significantly increases the risk for the progression of periodontal attachment loss (AL). Based on these findings we hypothesized that variations in the leukotoxicity are linked to disease progression in infected individuals. In the present study, the leukotoxicity of 239 clinical isolates of A. actinomycetemcomitans was analysed with different bioassays, and the genetic peculiarities of the isolates were related to their leukotoxicity based on examination with molecular techniques. The periodontal status of the individuals sampled for the presence of A. actinomycetemcomitans was examined longitudinally, and the importance of the observed variations in leukotoxicity was evaluated in relation to disease progression. Our data show that high leukotoxicity correlates with an enhanced risk for the progression of AL. The JP2 genotype isolates were all highly leukotoxic, while the isolates with an intact leukotoxin promoter (non-JP2 genotypes) showed substantial variation in leukotoxicity. Genetic characterization of the non-JP2 genotype isolates indicated the presence of highly leukotoxic genotypes of serotype b with similarities to the JP2 genotype. Based on these results, we conclude that A. actinomycetemcomitans harbours other highly virulent genotypes besides the previously described JP2 genotype. In addition, the results from the present study further highlight the importance of the leukotoxin as a key virulence factor in aggressive forms of periodontitis.

  19. Parents' Aggressive Influences and Children's Aggressive Problem Solutions with Peers

    ERIC Educational Resources Information Center

    Duman, Sarah; Margolin, Gayla

    2007-01-01

    This study examined children's aggressive and assertive solutions to hypothetical peer scenarios in relation to parents' responses to similar hypothetical social scenarios and parents' actual marital aggression. The study included 118 children ages 9 to 10 years old and their mothers and fathers. Children's aggressive solutions correlated with…

  20. Relational Aggression and Physical Aggression among Adolescent Cook Islands Students

    ERIC Educational Resources Information Center

    Page, Angela; Smith, Lisa F.

    2016-01-01

    Both physical and relational aggression are characterised by the intent to harm another. Physical aggression includes direct behaviours such as hitting or kicking; relational aggression involves behaviours designed to damage relationships, such as excluding others, spreading rumours, and delivering threats and verbal abuse. This study extended…

  1. Effects of different manual periodontal probes on periodontal measurements

    PubMed Central

    Holtfreter, Birte; Alte, Dietrich; Schwahn, Christian; Desvarieux, Moïse; Kocher, Thomas

    2013-01-01

    Aim To quantify the digit preference effect for three manual periodontal probes and to calculate correction values to enable comparison of studies with equal recording protocols, but different periodontal probes. Material and Methods A prospective in vivo crossover study was conducted with a six-sequence three-period design. Six examiners assessed attachment loss (AL), probing pocket depth (PD) and gingiva height (GH) at four surfaces, full-mouth, in six generally healthy subjects using three manual probes: PCP11 (3-3-3-2 mm increments), PCP2 (2 mm increments), and PCPUNC15 (1 mm increments). Results Distributions of AL, PD and GH differed between probes (p < 0.001). Compared with PCPUNC15, periodontal measurements coinciding with probe markings of PCP11 and PCP2, respectively, were preferentially named by examiners. Digit preference was most pronounced for PD, but less for AL and GH. In multilevel models, PD differed significantly between all three probes (p < 0.05); probe- and examiner-related effects were also observed for AL and GH. Correction values for pairwise combinations of probes were determined. Conclusions We provided empirical evidence and quantified the effect of probe type on periodontal measurements. Differences in probe type should be considered when comparing periodontal data within and between epidemiological studies and appropriate corrections, provided here, should be applied. PMID:22924328

  2. Periodontal diseases in children and adolescents.

    PubMed

    Clerehugh, V

    2008-04-26

    Unlike in adults, currently there are no nationally agreed guidelines for the assessment of periodontal diseases in children and adolescents. This paper considers the range of periodontal diseases that can affect youngsters and documents a simple periodontal screening system for the younger age groups. It includes principles of periodontal diagnosis and management for the practitioner to apply to the young patient and considers when to treat in practice and when to refer to a specialist.

  3. Grain decoration in aluminum oxynitride (ALON) from polishing on bound abrasive laps

    NASA Astrophysics Data System (ADS)

    Gregg, Leslie L.; Marino, Anne E.; Hayes, Jennifer C.; Jacobs, Stephen D.

    2004-01-01

    Aluminum oxynitride (ALON) is a polycrystalline material that has proven difficult to polish due to its grain structure. Bound abrasives are an effective means for polishing ALON, and work is being done with them to obtain good surfaces, with reasonable removal rates. Laps consisting of abrasives bound in epoxy matrices were created for polishing ALON. The effects of varying abrasive type, abrasive concentration, lap shape, coolant and load were studied. Metrology procedures were developed to monitor different aspects of the grain structure and numerically evaluate grain boundary decoration. Strategies were developed to polish ALON at acceptable rates with reasonably good surface quality. Work is directed toward finding optimal bound abrasive lap formulations that can be fabricated into ring and/or contour tools for testing on CNC machining platforms.

  4. Grain decoration in aluminum oxynitride (ALON) from polishing on bound abrasive laps

    NASA Astrophysics Data System (ADS)

    Marino, Anne E.; Hayes, Jennifer; Gregg, Leslie L.; Jacobs, Stephen D.

    2003-05-01

    Aluminum oxynitride (ALON) is a material with desirable qualities for a variety of applications that has proven difficult to polish because of its grain structure. Bound abrasives may prove to be an effective means of polishing it, and work is being done with them to obtain good surfaces on ALON, with reasonable removal rates. Laps consisting of abrasives bound in epoxy matrices have been created for polishing ALON. The effects of varying abrasive type, abrasive concentration, lap shape, coolant and load are being studied. Metrology procedures are being developed to monitor different aspects of the grain structure and numerically evaluate its decoration. Strategies have been developed to polish ALON at acceptable rates with reasonably good surface quality. Work is directed toward finding optimal bound abrasive lap formulations that can be fabricated into ring and/or contour tools for testing on CNC machining platforms.

  5. Methodology for Predicting the Onset of Widespread Fatigue Damage in Lap-Splice Joints

    NASA Technical Reports Server (NTRS)

    Newman, J. C., Jr.; Harris, C. E.; Piascik, R. S.; Dawicke, D. S.

    1998-01-01

    NASA has conducted an Airframe Structural Integrity Program to develop the methodology to predict the onset of widespread fatigue damage to lap-splice joints of fuselage structures. Several stress analysis codes have been developed or enhanced to analyze the lap-splice-joint configuration. Fatigue lives in lap-splice-joint specimens and fatigue-crack growth in a structural fatigue test article agreed well with calculations from small-crack theory and fatigue-crack growth analyses with the FASTRAN code. Residual-strength analyses of laboratory specimens and wide stiffened panels were predicted quite well from the critical crack-tip-opening angle (CTOA) fracture criterion and elastic-plastic finite-element analyses (two- or three-dimensional codes and the STAGS shell code).

  6. Large-scale Advanced Prop-fan (LAP) technology assessment report

    NASA Technical Reports Server (NTRS)

    Degeorge, C. L.

    1988-01-01

    The technologically significant findings and accomplishments of the Large Scale Advanced Prop-Fan (LAP) program in the areas of aerodynamics, aeroelasticity, acoustics and materials and fabrication are described. The extent to which the program goals related to these disciplines were achieved is discussed, and recommendations for additional research are presented. The LAP program consisted of the design, manufacture and testing of a near full-scale Prop-Fan or advanced turboprop capable of operating efficiently at speeds to Mach .8. An aeroelastically scaled model of the LAP was also designed and fabricated. The goal of the program was to acquire data on Prop-Fan performance that would indicate the technology readiness of Prop-Fans for practical applications in commercial and military aviation.

  7. Study on active lap tool influence function in grinding 1.8 m primary mirror.

    PubMed

    Haitao, Liu; Zhige, Zeng; Fan, Wu; Bin, Fan; Yongjian, Wan

    2013-11-01

    We present a theoretical modeling method to predict the ring tool influence function (TIF) based on the computer-controlled active lap process. The gap on the lap-grinding layer is considered, and its influence on the ring TIF is analyzed too. The relationship between the shape of the ring TIF and the lap-workpiece rotation speed ratio is discussed in this paper. The recipe for calculating dwell time for axisymmetric fabrication is discussed. The grinding process of a 1.8 m primary mirror is improved based on these results. The grinding process is accomplished after 30 circles of grinding, and the surface shape error is from PV 82 μm RMS 16.4 μm reduced to PV 13.5 μm RMS 2.5 μm.

  8. Measurements of fuselage skin strains and displacements near a longitudinal lap joint in a pressurized aircraft

    NASA Technical Reports Server (NTRS)

    Phillips, Edward P.; Britt, Vicki O.

    1991-01-01

    Strains and displacements in a small area near a longitudinal lap joint in the fuselage skin of a B737 aircraft were measured during a pressurization cycle to a differential pressure of 6.2 psi while the aircraft was on the ground. It was found that hoop strains were higher than longitudinal strains at each location; membrane strains in the unreinforced skin were higher than in the joint; membrane strains in the hoop direction, as well as radial displacements, tended to be highest at the mid-bay location between skin reinforcements; significant bending in the hoop direction occurred in the joint and in the skin near the joint, and the bending was unsymmetrically distributed about the stringer at the middle of the joint; and radial displacements were unsymmetrically distributed across the lap joint. The interpretation of the strain gage data for locations on the bonded and riveted lap joint assumed that the joint did not contain disbonded areas.

  9. Failure strength prediction for adhesively bonded single lap joints

    NASA Astrophysics Data System (ADS)

    Rahman, Niat Mahmud

    For adhesively bonded joint, failure strength depends on many factors such as material properties (both adhesive and adherend), specimen geometries, test environments, surface preparation procedures, etc. Failure occurs inside constitutive materials or along joint interfaces. Based on location, adhesively bonded failure mode can be classified as adhesive failure mode, cohesive failure mode and adherend failure mode. Failure mode directly affects the failure strength of joint. For last eight decades, researchers have developed analytical, empirical or semi-empirical methods capable of predicting failure strength for adhesively bonded joints generating either cohesive failure or adherend failure. Applicability of most of the methods is limited to particular cases. In this research, different failure modes for single lap joints (SLJs) were generated experimentally using epoxy based paste adhesive. Based on experimental data and analytical study, simplified failure prediction methods were developed for each failure mode. For adhesive failure mode, it is observed that peel stress distributions concur along interface near crack initiation points. All SLJs for this test endured consistent surface treatments. Geometric parameters of the joints were varied to study their effect on failure strength. Peel stress distributions were calculated using finite analysis (FEA). Based on peel stress distribution near crack initiation point, a failure model is proposed. Numerous analytical, empirical and semi-empirical models are available for predicting failure strengths of SLJs generating cohesive failures. However, most of the methods in the literature failed to capture failure behavior of SLJs having thickness of adhesive layer as variable. Cohesive failure mode was generated experimentally using aluminum as adherend and epoxy adhesive considering thickness of adhesive layers as variable within SLJs. Comparative study was performed among various methods. It was observed that

  10. Serotonin and Aggressiveness in Chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Serotonin (5-HT) regulates aggressive behavior in animals. This study examined if 5-HT regulation of aggressiveness is gene-dependent. Chickens from two divergently selected lines KGB and MBB (Kind Gentle Birds and Mean Bad Birds displaying low and high aggressiveness, respectively) and DXL (Dekalb ...

  11. Lessons learned and unlearned in periodontal microbiology

    PubMed Central

    Teles, Ricardo; Teles, Flavia; Frias-Lopez, Jorge; Paster, Bruce; Haffajee, Anne

    2013-01-01

    Periodontal diseases are initiated by bacterial species living in polymicrobial biofilms at or below the gingival margin and progress largely as a result of the inflammation initiated by specific subgingival species. In the past few decades, efforts to understand the microbiota of periodontal diseases have led to an exponential increase in information about biofilms associated with periodontal health and disease. In fact, the oral microbiota is one of the best characterized microbiomes that colonize the human body. Despite this increased knowledge, one has to ask if our fundamental concepts of the etiology and pathogenesis of periodontal diseases have really changed. In this chapter we will review how our comprehension of the structure and function of the subgingival microbiota evolved over the years in search of lessons learned and unlearned in periodontal microbiology. More specifically, this review focuses on: 1) how the data obtained through molecular techniques has impacted our knowledge of the etiology of periodontal infections; 2) the potential role of viruses in the etiopathogenesis of periodontal diseases; 3) how concepts of microbial ecology have expanded our understanding of host microbial interactions that might lead to periodontal diseases; 4) the role of inflammation in the pathogenesis of periodontal diseases; and 5) the impact of these evolving concepts on treatment and preventive approaches to periodontal infections. We will conclude by reviewing how novel systems biology approaches promise to unravel new details of the pathogenesis of periodontal diseases and, hopefully, lead to a better understanding of periodontal disease mechanisms. PMID:23574465

  12. LapF, the second largest Pseudomonas putida protein, contributes to plant root colonization and determines biofilm architecture.

    PubMed

    Martínez-Gil, Marta; Yousef-Coronado, Fátima; Espinosa-Urgel, Manuel

    2010-08-01

    We have investigated the role of LapF, one of the two largest proteins encoded in the genome of Pseudomonas putida KT2440, in bacterial colonization of solid surfaces. LapF is 6310 amino acids long, and is localized on the cell surface. The C-terminal region of the protein is essential for its secretion, which presumably requires the ABC transporter encoded by an operon (lapHIJ) adjacent to the lapF gene. Although the initial attachment stages are not different between the wild type and a lapF mutant, microcolony formation and subsequent development of a mature biofilm is impaired in the mutant. This is consistent with the expression pattern of lapF; activation of its promoter takes place at late stages of growth and is regulated by the alternative sigma factor RpoS. A lapF mutant is also affected in individual and competitive plant root colonization. In these assays, mixed microcolonies formed by cells of both the wild-type and the mutant strains could be observed but microcolonies of the mutant alone were not found. These data and the localization of the protein at discrete spots in areas of contact between cells in biofilms suggest that LapF determines the establishment of cell-cell interactions during sessile growth.

  13. The Growth of Multi-Site Fatigue Damage in Fuselage Lap Joints

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.; Willard, Scott A.

    1999-01-01

    Destructive examinations were performed to document the progression of multi-site damage (MSD) in three lap joint panels that were removed from a full scale fuselage test article that was tested to 60,000 full pressurization cycles. Similar fatigue crack growth characteristics were observed for small cracks (50 microns to 10 mm) emanating from counter bore rivets, straight shank rivets, and 100 deg counter sink rivets. Good correlation of the fatigue crack growth data base obtained in this study and FASTRAN Code predictions show that the growth of MSD in the fuselage lap joint structure can be predicted by fracture mechanics based methods.

  14. Smoking and periodontal disease severity.

    PubMed

    Martinez-Canut, P; Lorca, A; Magán, R

    1995-10-01

    This study was performed to assess the influence of smoking on periodontal disease severity. Data concerning periodontal status and smoking habits were collected from 889 periodontal patients: 340 male and 549 female, 21 to 76 years of age, 47.4% being non smokers and 52.6% smokers. Periodontal parameters, recorded by the same examiner (PMC), were: gingival recession (GR), Pocket depth (PD), Probing attachment level (PAL), and mobility (M). The influence of age, sex and tobacco consumption on these periodontal parameters was statistically evaluated using an analysis of variance (ANOVA) with covariates. A non-linear effect model was also fitted by taking the natural logarithms of the response variables (GR, PD, PAL) closer to biomedical phenomena. Mobility was analyzed by a chi2-test. The effect of smoking on periodontitis showed no association with age or with sex. Smoking, age and sex were shown to be statistically significant for periodontitis, by performing both univariate (t-test for equal means) and multivariate tests. p-values for smoking and periodontitis were: GR (p=0.000), PD (p=0.000), PAL (p=0.000) and M (P=0.015). Smoking one cigarette per day, up to 10, and up to 20, increased PAL by 0.5%, 5% and 10%, respectively. The impact of tobacco is comparable to the impact resulting from the factor of age in this sample, increasing PAL by 0.7% for each year of life. Comparison between smokers of less than 10 cigarettes per day (PAL mean 3.72 mm +/-0.86) and non-smokers (PAL mean 3.84 +/- 0.89) showed no differences in PAL (p=0.216), while comparison for smokers from 11 to 20 cigarettes (PAL mean 4.36 +/- 1.23) and for more than 20 cigarettes (PAL mean 4.50 +/- 1.04) demonstrated significant differences (p=0.000). These findings suggest that: (1) tobacco increases periodontal disease severity; (2) this effect is clinically evident above consumption of a certain quantity of tobacco.

  15. Trauma from occlusion. Periodontal concerns.

    PubMed

    Burgett, F G

    1995-04-01

    Application of the chronic disease model to IPD suggests that to be most effective, programs of prevention and treatment include measures to address as many of the identified risk factors as is possible. It remains to be determined if TO is involved in the initiation of IPD, for example, if individuals with TO are at greater risk for the development of IPD. There is evidence that TO is a risk factor in the progression of IPD. Tooth mobility is associated with and is a risk factor for increased attachment loss and increased bone loss in patients with periodontitis. Tooth mobility can be reduced by occlusal treatment. Clinical trials involving patients with periodontitis clearly establish that a better clinical periodontal attachment level response to treatment is obtained when occlusal adjustment is included as part of the treatment plan. Patients with advanced periodontal involvement benefit from occlusal treatment in terms of increased stability for the teeth and also in terms of oral comfort. Finally, There is no evidence that without occlusal treatment, periodontal patients who are in careful maintenance programs are more likely to suffer recurrence of IPD.

  16. LAP TGF-Beta Subset of CD4(+)CD25(+)CD127(-) Treg Cells is Increased and Overexpresses LAP TGF-Beta in Lung Adenocarcinoma Patients.

    PubMed

    Islas-Vazquez, Lorenzo; Prado-Garcia, Heriberto; Aguilar-Cazares, Dolores; Meneses-Flores, Manuel; Galicia-Velasco, Miriam; Romero-Garcia, Susana; Camacho-Mendoza, Catalina; Lopez-Gonzalez, Jose Sullivan

    2015-01-01

    Lung cancer is the leading cause of cancer death worldwide. Adenocarcinoma, the most commonly diagnosed histologic type of lung cancer, is associated with smoking. Cigarette smoke promotes inflammation on the airways, which might be mediated by Th17 cells. This inflammatory environment may contribute to tumor development. In contrast, some reports indicate that tumors may induce immunosuppressive Treg cells to dampen immune reactivity, supporting tumor growth and progression. Thus, we aimed to analyze whether chronic inflammation or immunosuppression predominates at the systemic level in lung adenocarcinoma patients, and several cytokines and Th17 and Treg cells were studied. Higher proportions of IL-17-producing CD4(+) T-cells were found in smoking control subjects and in lung adenocarcinoma patients compared to nonsmoking control subjects. In addition, lung adenocarcinoma patients increased both plasma concentrations of IL-2, IL-4, IL-6, and IL-10, and proportions of Latency Associated Peptide (LAP) TGF-β subset of CD4(+)CD25(+)CD127(-) Treg cells, which overexpressed LAP TGF-β. This knowledge may lead to the development of immunotherapies that could inhibit the suppressor activity mediated by the LAP TGF-β subset of CD4(+)CD25(+)CD127(-) Treg cells to promote reactivity of immune cells against lung adenocarcinoma cells.

  17. LAP TGF-Beta Subset of CD4+CD25+CD127− Treg Cells is Increased and Overexpresses LAP TGF-Beta in Lung Adenocarcinoma Patients

    PubMed Central

    Islas-Vazquez, Lorenzo; Prado-Garcia, Heriberto; Aguilar-Cazares, Dolores; Meneses-Flores, Manuel; Galicia-Velasco, Miriam; Romero-Garcia, Susana; Camacho-Mendoza, Catalina; Lopez-Gonzalez, Jose Sullivan

    2015-01-01

    Lung cancer is the leading cause of cancer death worldwide. Adenocarcinoma, the most commonly diagnosed histologic type of lung cancer, is associated with smoking. Cigarette smoke promotes inflammation on the airways, which might be mediated by Th17 cells. This inflammatory environment may contribute to tumor development. In contrast, some reports indicate that tumors may induce immunosuppressive Treg cells to dampen immune reactivity, supporting tumor growth and progression. Thus, we aimed to analyze whether chronic inflammation or immunosuppression predominates at the systemic level in lung adenocarcinoma patients, and several cytokines and Th17 and Treg cells were studied. Higher proportions of IL-17-producing CD4+ T-cells were found in smoking control subjects and in lung adenocarcinoma patients compared to nonsmoking control subjects. In addition, lung adenocarcinoma patients increased both plasma concentrations of IL-2, IL-4, IL-6, and IL-10, and proportions of Latency Associated Peptide (LAP) TGF-β subset of CD4+CD25+CD127− Treg cells, which overexpressed LAP TGF-β. This knowledge may lead to the development of immunotherapies that could inhibit the suppressor activity mediated by the LAP TGF-β subset of CD4+CD25+CD127− Treg cells to promote reactivity of immune cells against lung adenocarcinoma cells. PMID:26582240

  18. Motives in Sexual Aggression: The Chinese Context.

    ERIC Educational Resources Information Center

    Tang, Catherine So-Kum; And Others

    1993-01-01

    Compared sexual and aggressive motives for sexual aggression in Chinese college students. Male undergraduates (N=146) completed self-report measures. Results suggest that sex guilt and aggressive guilt acted as inhibitors for their respective drives and sexual aggression resulted from aggressive, rather than sexual, motives. Sexual aggression may…

  19. Periodontics--tissue engineering and the future.

    PubMed

    Douglass, Gordon L

    2005-03-01

    Periodontics has a long history of utilizing advances in science to expand and improve periodontal therapies. Recently the American Academy of Periodontology published the findings of the Contemporary Science Workshop, which conducted state-of-the-art evidence-based reviews of current and emerging areas in periodontics. The findings of this workshop provide the basis for an evidence-based approach to periodontal therapy. While the workshop evaluated all areas of periodontics, it is in the area of tissue engineering that the most exciting advances are becoming a reality.

  20. Periodontics in the next millennium.

    PubMed

    Vandersall, D C

    1998-07-01

    This article prognosticates where periodontology will be in the next millennium. The forecasting of such events is wrought with confusion because such predictions are shadowed by bias, dogmatism, prejudice, experiences, and opinions from either a closed or open mind. The results of the survey from 101 periodontists reflect opinions from varied backgrounds, years of clinical experience, and individual levels of success or failure. The responses cannot be tested for accuracy or duplicated by another survey except to wait out the test of time for the year 2025. Clinicians will be challenged to make decisions on accepting new techniques and concepts as these are brought into the therapeutic fold of periodontics. The clinician will be met with new possibilities as a paradigm shift is inevitable for periodontal practice in the next millennium. After all, who would have thought in the 1960s, the soft tissue augmentation era, that 22 years later in 1982, the regeneration of the lost attachment apparatus (alveolar bone, cementum, and periodontal ligament) would become a reality. This survey strongly suggests that by the end of the first quarter of the twenty-first century, local delivery of antimicrobials, growth and differentiation factors, and root biomodification agents will have a major impact on the practice of periodontics. One thing is certain, in the next millennium, considering the responses from this survey, a new era in periodontics will be here. By the year 2025, the research, development, and dissemination of new periodontal knowledge will be beyond the imagination from what was considered usual and customary for the twentieth century.

  1. Critical issues in clinical periodontal research.

    PubMed

    Preshaw, Philip M

    2012-06-01

    As periodontal researchers and clinicians, we are challenged every day to make decisions relating to the clinical management of our patients and about how best to conduct clinical periodontal research. This volume of Periodontology 2000 addresses some of the critical issues in contemporary clinical periodontics and periodontal research that are of direct relevance to clinicians, researchers, teachers and students. The 11 review articles in this volume of Periodontology 2000 focus on aspects of periodontal research methodology and clinical periodontology. In terms of research methodology, the articles aim to inform the reader on topics relating to randomized controlled trials in periodontal research, evidence-based dentistry, calibration of clinical examiners and statistics relevant to periodontal research. The clinical periodontology articles address issues relating to decisions on retaining periodontally compromised teeth or replacing them with implants, periodontal management in the patient with osteoporosis, surgical approaches for root coverage and the emerging science of advanced regenerative technologies, including the use of stem cells, for periodontal regeneration. It is hoped that these critical reviews will address many of the dilemmas that confront us on a regular basis and provide practical guidance to those engaged in both clinical periodontology and clinical periodontal research.

  2. [Orthodontic treatment of malocclusion with periodontitis].

    PubMed

    Maruchi, N; Miyajima, K; Iizuka, T; Inagaki, K; Noguchi, T; Sakai, M

    1990-12-01

    Adults with untreated malocclusions suffer from more periodontal disease than if their malocclusion had been corrected orthodontically. What orthodontists can offer in the management of patients with periodontal disease, how they can help the periodontists and the patients, and how the periodontists can help the orthodontist make treatment safe and purposefully are widely discussed. The purpose of this study is, therefore, to discuss how orthodontic patients with severe periodontitis could be treated and what we should do for these patients during the treatment as well as at their initial visit. One case is presented as an example of treatment for malocclusion with sever periodontitis: The patient was a 23 years 8 months female with a chief complaint of protrusion of upper incisors. Since clinical examination revealed severe periodontitis, periodontal treatment was undertaken for one year prior to orthodontic treatment. From these observations, we are conviced of the importance again of the global approach and the team treatment method in treating malocclusions with periodontitis.

  3. Association between postmenopausal osteoporosis and experimental periodontitis.

    PubMed

    Luo, Kai; Ma, Souzhi; Guo, Jianbin; Huang, Yongling; Yan, Fuhua; Xiao, Yin

    2014-01-01

    To investigate the correlation between postmenopausal osteoporosis (PMO) and the pathogenesis of periodontitis, ovariectomized rats were generated and the experimental periodontitis was induced using a silk ligature. The inflammatory factors and bone metabolic markers were measured in the serum and periodontal tissues of ovariectomized rats using an automatic chemistry analyzer, enzyme-linked immunosorbent assays, and immunohistochemistry. The bone mineral density of whole body, pelvis, and spine was analyzed using dual-energy X-ray absorptiometry and image analysis. All data were analyzed using SPSS 13.0 statistical software. It was found that ovariectomy could upregulate the expression of interleukin- (IL-)6, the receptor activator of nuclear factor- κB ligand (RANKL), and osteoprotegerin (OPG) and downregulate IL-10 expression in periodontal tissues, which resulted in progressive alveolar bone loss in experimental periodontitis. This study indicates that changes of cytokines and bone turnover markers in the periodontal tissues of ovariectomized rats contribute to the damage of periodontal tissues.

  4. Periodontal status in snow leopards.

    PubMed

    Cook, R A; Stoller, N H

    1986-11-01

    Periodontal examinations were performed on ten 1- to 22-year-old snow leopards (6 males and 4 females), using dentistry methods for determining the plaque and gingival indices. All tooth surfaces were probed, and alveolar bone attachment loss was determined. After subgingival plaque removal, plaque specimens were examined for differential bacterial morphotypes. The small number of leopards evaluated precluded definitive statistical analysis. However, the progression from gingival health to gingivitis to periodontitis was similar to that seen in man. Therefore, the use of plaque index, gingival index, alveolar bone attachment loss, and differential bacterial morphotypes can be used to determine the dental health of snow leopards.

  5. Determination of Arsenic Poisoning and Metabolism in Hair by Synchrotron Radiation: The Case of Phar Lap

    SciTech Connect

    Kempson, Ivan M.; Henry, Dermot A.

    2010-08-26

    Fresh physical evidence about the demise of the racehorse Phar Lap (see photograph) has been gathered from the study of mane hair samples by synchrotron radiation analysis with high resolution X-ray fluorescence (XRF) and X-ray absorption near edge structure (XANES) analyses. The results are indicative of arsenic ingestion and metabolism, and show that the racing champion died from arsenic poisoning.

  6. Too Many Laps? Try This Activity Recipe -- They'll Be Back for More!

    ERIC Educational Resources Information Center

    McCannell, Daryle

    2000-01-01

    Discusses the importance of creative warmup activities (other than running laps) to motivate students in physical activity class, explaining that the basic ingredients are: a smiling, energetic instructor; appropriate body preparation; a mold for children's boundless energy; and some creative planning. The article describes several creative warmup…

  7. Learning Activity Package, Physical Science. LAP Numbers 8, 9, 10, and 11.

    ERIC Educational Resources Information Center

    Williams, G. J.

    These four units of the Learning Activity Packages (LAPs) for individualized instruction in physical science cover nuclear reactions, alpha and beta particles, atomic radiation, medical use of nuclear energy, fission, fusion, simple machines, Newton's laws of motion, electricity, currents, electromagnetism, Oersted's experiment, sound, light,…

  8. Design Considerations of Polishing Lap for Computer-Controlled Cylindrical Polishing Process

    NASA Technical Reports Server (NTRS)

    Khan, Gufran S.; Gubarev, Mikhail; Arnold, William; Ramsey, Brian D.

    2009-01-01

    This paper establishes a relationship between the polishing process parameters and the generation of mid spatial-frequency error. The consideration of the polishing lap design to optimize the process in order to keep residual errors to a minimum and optimization of the process (speeds, stroke, etc.) and to keep the residual mid spatial-frequency error to a minimum, is also presented.

  9. The Fundamental Reasons Why Laptop Computers should not be Used on Your Lap.

    PubMed

    Mortazavi, S A R; Taeb, S; Mortazavi, S M J; Zarei, S; Haghani, M; Habibzadeh, P; Shojaei-Fard, M B

    2016-12-01

    As a tendency to use new technologies, gadgets such as laptop computers are becoming more popular among students, teachers, businessmen and office workers. Today laptops are a great tool for education and learning, work and personal multimedia. Millions of men, especially those in the reproductive age, are frequently using their laptop computers on the lap (thigh). Over the past several years, our lab has focused on the health effects of exposure to different sources of electromagnetic fields such as cellular phones, mobile base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons and Magnetic Resonance Imaging (MRI). Our own studies as well as the studies performed by other researchers indicate that using laptop computers on the lap adversely affects the male reproductive health. When it is placed on the lap, not only the heat from a laptop computer can warm men's scrotums, the electromagnetic fields generated by laptop's internal electronic circuits as well as the Wi-Fi Radiofrequency radiation hazards (in a Wi-Fi connected laptop) may decrease sperm quality. Furthermore, due to poor working posture, laptops should not be used on the lap for long hours.

  10. Learning Activity Package, Algebra 103-104, LAPs 23-33.

    ERIC Educational Resources Information Center

    Evans, Diane

    This set of 11 teacher-prepared Learning Activity Packages (LAPs) in intermediate algebra covers number systems; exponents and radicals; polynomials and factoring; rational expressions; coordinate geometry; relations, functions, and inequalities; quadratic equations and inequalities; Quadratic functions; systems of equations and inequalities;…

  11. Learning Activity Package, Chemistry I. LAP Numbers 22, 23, 24, 25, 26, 27, and 28.

    ERIC Educational Resources Information Center

    Jones, Naomi

    As a set of seven Learning Activity Packages (LAPs) for individualized instruction in chemistry, the units cover the unit system, matter, energy, atomic structures, chemical formulas, physical states of matter, solutions and suspensions, ionization, acids, bases, and salts. Each unit contains a rationale for the material; a list of behavioral…

  12. The Early Learning Accomplishment Profile (Early LAP) Examiner's Manual and Reliability and Validity Technical Report.

    ERIC Educational Resources Information Center

    Hardin, Belinda J.; Peisner-Feinberg, Ellen S.

    The Early Learning Accomplishment Profile (Early LAP) provides a systematic method for observing children's functioning in the birth to 36-month age range in order to assist teachers, clinicians, and parents in assessing individual skills development in six developmental domains: gross motor, fine motor, cognition, language, self-help, and social…

  13. The impact of layer thickness on the performance of additively manufactured lapping tools

    NASA Astrophysics Data System (ADS)

    Williams, Wesley B.

    2015-10-01

    Lower cost additive manufacturing (AM) machines which have emerged in recent years are capable of producing tools, jigs, and fixtures that are useful in optical fabrication. In particular, AM tooling has been shown to be useful in lapping glass workpieces. Various AM machines are distinguished by the processes, materials, build times, and build resolution they provide. This research investigates the impact of varied build resolution (specifically layer resolution) on the lapping performance of tools built using the stereolithographic assembly (SLA) process in 50 μm and 100 μm layer thicknesses with a methacrylate photopolymer resin on a high resolution desktop printer. As with previous work, the lapping tools were shown to remove workpiece material during the lapping process, but the tools themselves also experienced significant wear on the order of 2-3 times the mass loss of the glass workpieces. The tool wear rates for the 100 μm and 50 μm layer tools were comparable, but the 50 μm layer tool was 74% more effective at removing material from the glass workpiece, which is attributed to some abrasive particles being trapped in the coarser surface of the 100 um layer tooling and not being available to interact with the glass workpiece. Considering the tool wear, these additively manufactured tools are most appropriate for prototype tooling where the low cost (<$45) and quick turnaround make them attractive when compared to a machined tool.

  14. Fracture analysis of multi-site cracking in fuselage lap joints

    NASA Astrophysics Data System (ADS)

    Beuth, J. L.; Hutchinson, J. W.

    1994-09-01

    A two-dimensional plane stress elastic fracture mechanics analysis of a cracked lap joint fastened by rigid pins is presented and results are applied to the problem of multi-site damage (MSD) in riveted lap joints of aircraft fuselage skins. Two problems are addressed, the problem of equal length MSD cracks and the problem of alternating length MSD cracks. For the problem of equal length cracks, two models of rivet/skin interactions are studied and the role of residual stresses due to the riveting process is explored. Stress intensity factors are obtained as a function of normalized crack length. Also, the load distribution among rivet rows and the compliance change of the joint due to MSD cracking are obtained. For the problem of alternating length cracks, attention is focussed on how load is distributed between columns of rivets and how this load shedding can alter crack tip stress intensity factors. The equal and alternating length crack analyses reveal no clear-cut mechanism to explain the relative uniformity of fatigue cracks emerging from lap joint rivet holes in actual aircraft and in mechanical lap joint tests.

  15. Learning Activity Package, Physical Science. LAP Numbers 1, 2, 3, and 4.

    ERIC Educational Resources Information Center

    Williams, G. J.

    These four units of the Learning Activity Packages (LAPs) for individualized instruction in physical science cover measuring techniques, operations of instruments, metric system heat, matter, energy, elements, atomic numbers, isotopes, molecules, mixtures, compounds, physical and chemical properties, liquids, solids, and gases. Each unit contains…

  16. iLAP: a workflow-driven software for experimental protocol development, data acquisition and analysis

    PubMed Central

    2009-01-01

    Background In recent years, the genome biology community has expended considerable effort to confront the challenges of managing heterogeneous data in a structured and organized way and developed laboratory information management systems (LIMS) for both raw and processed data. On the other hand, electronic notebooks were developed to record and manage scientific data, and facilitate data-sharing. Software which enables both, management of large datasets and digital recording of laboratory procedures would serve a real need in laboratories using medium and high-throughput techniques. Results We have developed iLAP (Laboratory data management, Analysis, and Protocol development), a workflow-driven information management system specifically designed to create and manage experimental protocols, and to analyze and share laboratory data. The system combines experimental protocol development, wizard-based data acquisition, and high-throughput data analysis into a single, integrated system. We demonstrate the power and the flexibility of the platform using a microscopy case study based on a combinatorial multiple fluorescence in situ hybridization (m-FISH) protocol and 3D-image reconstruction. iLAP is freely available under the open source license AGPL from http://genome.tugraz.at/iLAP/. Conclusion iLAP is a flexible and versatile information management system, which has the potential to close the gap between electronic notebooks and LIMS and can therefore be of great value for a broad scientific community. PMID:19941647

  17. Progerin reduces LAP2α-telomere association in Hutchinson-Gilford progeria.

    PubMed

    Chojnowski, Alexandre; Ong, Peh Fern; Wong, Esther S M; Lim, John S Y; Mutalif, Rafidah A; Navasankari, Raju; Dutta, Bamaprasad; Yang, Henry; Liow, Yi Y; Sze, Siu K; Boudier, Thomas; Wright, Graham D; Colman, Alan; Burke, Brian; Stewart, Colin L; Dreesen, Oliver

    2015-08-27

    Hutchinson-Gilford progeria (HGPS) is a premature ageing syndrome caused by a mutation in LMNA, resulting in a truncated form of lamin A called progerin. Progerin triggers loss of the heterochromatic marker H3K27me3, and premature senescence, which is prevented by telomerase. However, the mechanism how progerin causes disease remains unclear. Here, we describe an inducible cellular system to model HGPS and find that LAP2α (lamina-associated polypeptide-α) interacts with lamin A, while its interaction with progerin is significantly reduced. Super-resolution microscopy revealed that over 50% of telomeres localize to the lamina and that LAP2α association with telomeres is impaired in HGPS. This impaired interaction is central to HGPS since increasing LAP2α levels rescues progerin-induced proliferation defects and loss of H3K27me3, whereas lowering LAP2 levels exacerbates progerin-induced defects. These findings provide novel insights into the pathophysiology underlying HGPS, and how the nuclear lamina regulates proliferation and chromatin organization.

  18. Learning Activity Package, Physical Science. LAP Numbers 5, 6, and 7.

    ERIC Educational Resources Information Center

    Williams, G. J.

    These three units of the Learning Activity Packages (LAPs) for individualized instruction in physical science cover the physical and chemical properties of water, dehydration of crystals, solutions, acidity, strong and weak bases, neutral properties of salts, amorphous forms of carbon, hydrocarbons, and petroleum products. Each unit contains a…

  19. Learning Activity Package, American Civics 92, LAPs 1 Through 3 and 5 Through 9.

    ERIC Educational Resources Information Center

    Calhoun, B. C.

    This self paced program in American Civics is for the ninth grade student who needs help on basic skills and who plans to enroll in vocational or business courses. Instructional materials, written at 9th grade level, consist of eight Learning Activity Packages (LAPs) on the following topics: Citizenship and Our Democracy; The Constitution of the…

  20. Learning Activity Package, American Civics 94, LAPs 1 Through 4 and 6 Through 9.

    ERIC Educational Resources Information Center

    Calhoun, B. C.; And Others

    This self-paced program in American Civics is for ninth grade students who definitely plan further education after high school, who have better than average grades, and who will do more than the minimum required work. Instructional materials written at 9th grade level or above consist of Learning Activity Packages (LAPs) on the following topics:…

  1. The Effectiveness of Lap-Dissolving Projections for Visualizing in Three Dimensions.

    ERIC Educational Resources Information Center

    Wood, James K.

    1983-01-01

    A study investigated the effectiveness of stereochemistry lap-dissolve projection as an aid to students in developing three-dimensional imaging and whether certain visual orientation tasks could be correlated with aptitude. Students found the slides helpful, and a modest correlation of achievement and visual skills was found. (MSE)

  2. Learning Activity Package, Biology, LAPs 12, 13, 15, 17, and 18.

    ERIC Educational Resources Information Center

    Rhoden, Bruce

    Included is a set of five teacher-prepared Learning Activity Packages (LAPs) for individualized instruction in topics in biology. The units cover the topics of individuals and populations, communities and ecosystems, diversity, plant functions, and animal functions. Each unit contains a rationale for the material; a list of behavioral objectives…

  3. The Fundamental Reasons Why Laptop Computers should not be Used on Your Lap

    PubMed Central

    Mortazavi, S.A.R.; Taeb, S.; Mortazavi, S.M.J.; Zarei, S.; Haghani, M.; Habibzadeh, P.; Shojaei-fard, M.B.

    2016-01-01

    As a tendency to use new technologies, gadgets such as laptop computers are becoming more popular among students, teachers, businessmen and office workers. Today laptops are a great tool for education and learning, work and personal multimedia. Millions of men, especially those in the reproductive age, are frequently using their laptop computers on the lap (thigh). Over the past several years, our lab has focused on the health effects of exposure to different sources of electromagnetic fields such as cellular phones, mobile base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons and Magnetic Resonance Imaging (MRI). Our own studies as well as the studies performed by other researchers indicate that using laptop computers on the lap adversely affects the male reproductive health. When it is placed on the lap, not only the heat from a laptop computer can warm men’s scrotums, the electromagnetic fields generated by laptop’s internal electronic circuits as well as the Wi-Fi Radiofrequency radiation hazards (in a Wi-Fi connected laptop) may decrease sperm quality. Furthermore, due to poor working posture, laptops should not be used on the lap for long hours. PMID:28144597

  4. Improving Critical Thinking Skills Using Learning Model Logan Avenue Problem Solving (LAPS)-Heuristic

    ERIC Educational Resources Information Center

    Anggrianto, Desi; Churiyah, Madziatul; Arief, Mohammad

    2016-01-01

    This research was conducted in order to know the effect of Logan Avenue Problem Solving (LAPS)-Heuristic learning model towards critical thinking skills of students of class X Office Administration (APK) in SMK Negeri 1 Ngawi, East Java, Indonesia on material curve and equilibrium of demand and supply, subject Introduction to Economics and…

  5. Progerin reduces LAP2α-telomere association in Hutchinson-Gilford progeria

    PubMed Central

    Chojnowski, Alexandre; Ong, Peh Fern; Wong, Esther SM; Lim, John SY; Mutalif, Rafidah A; Navasankari, Raju; Dutta, Bamaprasad; Yang, Henry; Liow, Yi Y; Sze, Siu K; Boudier, Thomas; Wright, Graham D; Colman, Alan; Burke, Brian; Stewart, Colin L; Dreesen, Oliver

    2015-01-01

    Hutchinson-Gilford progeria (HGPS) is a premature ageing syndrome caused by a mutation in LMNA, resulting in a truncated form of lamin A called progerin. Progerin triggers loss of the heterochromatic marker H3K27me3, and premature senescence, which is prevented by telomerase. However, the mechanism how progerin causes disease remains unclear. Here, we describe an inducible cellular system to model HGPS and find that LAP2α (lamina-associated polypeptide-α) interacts with lamin A, while its interaction with progerin is significantly reduced. Super-resolution microscopy revealed that over 50% of telomeres localize to the lamina and that LAP2α association with telomeres is impaired in HGPS. This impaired interaction is central to HGPS since increasing LAP2α levels rescues progerin-induced proliferation defects and loss of H3K27me3, whereas lowering LAP2 levels exacerbates progerin-induced defects. These findings provide novel insights into the pathophysiology underlying HGPS, and how the nuclear lamina regulates proliferation and chromatin organization. DOI: http://dx.doi.org/10.7554/eLife.07759.001 PMID:26312502

  6. Transperineal aggressive angiomyxoma.

    PubMed

    Pereira, Pedro; Melo Abreu, Elisa; Cunha, Teresa Margarida; Rolim, Inês

    2017-04-11

    A 45-year-old woman with a history of total hysterectomy with adnexal preservation for uterine leiomyomas presented to our hospital with a right gluteal palpable mass, which she first noticed 6 months before and had progressively enlarged since then.Radiological studies revealed a 14 cm lesion with translevator growth that displaced rather than invaded adjacent structures, with a peculiar whorled pattern on T2-weighted MRI, which enhanced following gadolinium administration. CT-guided biopsy was performed, and in conjunction with imaging features the diagnosis of an aggressive angiomyxoma was assumed and confirmed following surgical excision.

  7. Determination of the Corrosive Conditions Present within Aircraft Lap-Splice Joints

    NASA Technical Reports Server (NTRS)

    Lewis, Karen S.; Kelly, Robert G.; Piascik, Robert S.

    1999-01-01

    The complexity of airframe structure lends itself to damage resulting from crevice corrosion. Fuselage lap-splice joints are a particularly important structural detail in this regard because of the difficulty associated with detection and measurement of corrosion in these occluded regions. The objective of this work is to develop a laboratory corrosion test protocol to identify the chemistry to which lap joints are exposed and to develop a model of the corrosion within the joints. A protocol for collecting and identifying the chemistry of airframe crevice corrosion has been developed. Capillary electrophoresis (CE) is used to identify the ionic species contained in corrosion product samples removed from fuselage lap splice joints. CE analysis has been performed on over sixty corrosion product samples removed from both civilian and military aircraft. Over twenty different ions have been detected. Measurements of pH of wetted corroded surfaces indicated an alkaline occluded solution. After determining the species present and their relative concentrations, the resultant solution was reproduced in bulk and electrochemical tests were performed to determine the corrosion rate. Electrochemical analyses of the behavior of AA2024-T3 in these solutions gave corrosion rates of up to 250 microns per year (10 mpy). Additional tests have determined the relative importance of each of the detected ions in model solutions used for future predictive tests. The statistically significant ions have been used to create a second generation solution. Laboratory studies have also included exposure tests involving artificial lap joints exposed to various simulated bulk and crevice environments. The extent and morphology of the attack in artificial lap joints has been compared to studies of corroded samples from actual aircraft. Other effects, such as temperature and potential, as well as the impact of the environment on fatigue crack growth have also been studied.

  8. Application of lap laser welding technology on stainless steel railway vehicles

    NASA Astrophysics Data System (ADS)

    Wang, Hongxiao; Wang, Chunsheng; He, Guangzhong; Li, Wei; Liu, Liguo

    2016-10-01

    Stainless steel railway vehicles with so many advantages, such as lightweight, antirust, low cost of maintenance and simple manufacturing process, so the production of high level stainless steel railway vehicles has become the development strategy of European, American and other developed nations. The current stainless steel railway vehicles body and structure are usually assembled by resistance spot welding process. The weak points of this process are the poor surface quality and bad airtight due to the pressure of electrodes. In this study, the partial penetration lap laser welding process was investigated to resolve the problems, by controlling the laser to stop at the second plate in the appropriate penetration. The lap laser welding joint of stainless steel railway vehicle car body with partial penetration has higher strength and surface quality than those of resistance spot welding joint. The biggest problem of lap laser welding technology is to find the balance of the strength and surface quality with different penetrations. The mechanism of overlap laser welding of stainless steel, mechanical tests, microstructure analysis, the optimization of welding parameters, analysis of fatigue performance, the design of laser welding stainless steel railway vehicles structure and the development of non-destructive testing technology were systematically studied before lap laser welding process to be applied in manufacture of railway vehicles. The results of the experiments and study show that high-quality surface state and higher fatigue strength can be achieved by the partial penetration overlap laser welding of the side panel structure, and the structure strength of the car body can be higher than the requirements of En12663, the standard of structural requirements of railway vehicles bodies. Our company has produced the stainless steel subway and high way railway vehicles by using overlap laser welding technology. The application of lap laser welding will be a big

  9. The Characteristics of Fatigue Damage in the Fuselage Riveted Lap Splice Joint

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.; Willard, Scott A.

    1997-01-01

    An extensive data base has been developed to form the physical basis for new analytical methodology to predict the onset of widespread fatigue damage in the fuselage lap splice joint. The results of detailed destructive examinations have been cataloged to describe the physical nature of MSD in the lap splice joint. ne catalog includes a detailed description, e.g., crack initiation, growth rates, size, location, and fracture morphology, of fatigue damage in the fuselage lap splice joint structure. Detailed examinations were conducted on a lap splice joint panel removed from a full scale fuselage test article after completing a 60,000 cycle pressure test. The panel contained a four bay region that exhibited visible outer skin cracks and regions of crack link-up along the upper rivet row. Destructive examinations revealed undetected fatigue damage in the outer skin, inner skin, and tear strap regions. Outer skin fatigue cracks were found to initiate by fretting damage along the faying surface. The cracks grew along the faying surface to a length equivalent to two to three skin thicknesses before penetrating the outboard surface of the outer skin. Analysis of fracture surface marker bands produced during full scale testing revealed that all upper rivet row fatigue cracks contained in a dim bay region grow at similar rates; this important result suggests that fracture mechanics based methods can be used to predict the growth of outer skin fatigue cracks in lap splice structure. Results are presented showing the affects of MSD and out-of-plane pressure loads on outer skin crack link-up.

  10. Myhre and LAPS syndromes: clinical and molecular review of 32 patients

    PubMed Central

    Michot, Caroline; Le Goff, Carine; Mahaut, Clémentine; Afenjar, Alexandra; Brooks, Alice S; Campeau, Philippe M; Destree, Anne; Di Rocco, Maja; Donnai, Dian; Hennekam, Raoul; Heron, Delphine; Jacquemont, Sébastien; Kannu, Peter; Lin, Angela E; Manouvrier-Hanu, Sylvie; Mansour, Sahar; Marlin, Sandrine; McGowan, Ruth; Murphy, Helen; Raas-Rothschild, Annick; Rio, Marlène; Simon, Marleen; Stolte-Dijkstra, Irene; Stone, James R; Sznajer, Yves; Tolmie, John; Touraine, Renaud; van den Ende, Jenneke; Van der Aa, Nathalie; van Essen, Ton; Verloes, Alain; Munnich, Arnold; Cormier-Daire, Valérie

    2014-01-01

    Myhre syndrome is characterized by short stature, brachydactyly, facial features, pseudomuscular hypertrophy, joint limitation and hearing loss. We identified SMAD4 mutations as the cause of Myhre syndrome. SMAD4 mutations have also been identified in laryngotracheal stenosis, arthropathy, prognathism and short stature syndrome (LAPS). This study aimed to review the features of Myhre and LAPS patients to define the clinical spectrum of SMAD4 mutations. We included 17 females and 15 males ranging in age from 8 to 48 years. Thirty were diagnosed with Myhre syndrome and two with LAPS. SMAD4 coding sequence was analyzed by Sanger sequencing. Clinical and radiological features were collected from a questionnaire completed by the referring physicians. All patients displayed a typical facial gestalt, thickened skin, joint limitation and muscular pseudohypertrophy. Growth retardation was common (68.7%) and was variable in severity (from −5.5 to −2 SD), as was mild-to-moderate intellectual deficiency (87.5%) with additional behavioral problems in 56.2% of the patients. Significant health concerns like obesity, arterial hypertension, bronchopulmonary insufficiency, laryngotracheal stenosis, pericarditis and early death occurred in four. Twenty-nine patients had a de novo heterozygous SMAD4 mutation, including both patients with LAPS. In 27 cases mutation affected Ile500 and in two cases Arg496. The three patients without SMAD4 mutations had typical findings of Myhre syndrome. Myhre–LAPS syndrome is a clinically homogenous condition with life threatening complications in the course of the disease. Our identification of SMAD4 mutations in 29/32 cases confirms that SMAD4 is the major gene responsible for Myhre syndrome. PMID:24424121

  11. Expression of leucine aminopeptidase 3 (LAP3) correlates with prognosis and malignant development of human hepatocellular carcinoma (HCC).

    PubMed

    Tian, Si-Yuan; Chen, Shou-Hua; Shao, Bing-Feng; Cai, Hong-Yu; Zhou, Yuan; Zhou, Yi-Long; Xu, Ai-Bing

    2014-01-01

    Leucine aminopeptidases (LAPs) were associated with tumor cell proliferation, invasion and/or angiogenesis. LAP3 is one important member of this family. However, its clinical significance and biological function in hepatocellular carcinoma (HCC) remains unknown. In the present study, we demonstrated that LAP3 expression was significantly up-regulated in HCC tissues as well as cells and was closely correlated with lower differentiation, positive lymph node metastasis and high Ki-67 expression, indicating a poor prognosis. Then cell viability assays, flow cytometry assays, wound-healing assays and matrigel invasion assays were performed to demonstrate that LAP3 promoted HCC cells proliferation by regulating G1/S checkpoint in cell cycle and advanced HCC cells migration. Furthermore, we discovered that knockdown LAP3 will enhance the sensitivity of HCC cells to cisplatin, thus promoting the cell death of HCC cells. Collectively, our results indicated that up-regulated expression of LAP3 might contribute to the proliferation and metastasis of HCC. Our data gains greater insight into the cancer-promoting role of LAP3 and its functions in HCC cells, possibly providing potential therapeutic strategies for clinical trials.

  12. The nature of human aggression.

    PubMed

    Archer, John

    2009-01-01

    Human aggression is viewed from four explanatory perspectives, derived from the ethological tradition. The first consists of its adaptive value, which can be seen throughout the animal kingdom, involving resource competition and protection of the self and offspring, which has been viewed from a cost-benefit perspective. The second concerns the phylogenetic origin of aggression, which in humans involves brain mechanisms that are associated with anger and inhibition, the emotional expression of anger, and how aggressive actions are manifest. The third concerns the origin of aggression in development and its subsequent modification through experience. An evolutionary approach to development yields conclusions that are contrary to the influential social learning perspective, notably that physical aggression occurs early in life, and its subsequent development is characterized by learned inhibition. The fourth explanation concerns the motivational mechanisms controlling aggression: approached from an evolutionary background, these mechanisms range from the inflexible reflex-like responses to those incorporating rational decision-making.

  13. Periodontitis and systemic lupus erythematosus.

    PubMed

    Sete, Manuela Rubim Camara; Figueredo, Carlos Marcelo da Silva; Sztajnbok, Flavio

    2016-01-01

    A large number of studies have shown a potential association between periodontal and autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus (SLE). Similar mechanisms of tissue destruction concerning periodontitis and other autoimmune diseases have stimulated the study of a possible relationship between these conditions. This study aims to review the literature about this potential association and their different pathogenic mechanisms. Considering that periodontal disease is a disease characterized by inflammation influenced by infectious factors, such as SLE, it is plausible to suggest that SLE would influence periodontal disease and vice versa. However, this issue is not yet fully elucidated and several mechanisms have been proposed to explain this association, as deregulation mainly in innate immune system, with action of phagocytic cells and proinflammatory cytokines such as IL-1β and IL-18 in both conditions' pathogenesis, leading to tissue destruction. However, studies assessing the relationship between these diseases are scarce, and more studies focused on common immunological mechanisms should be conducted to further understanding.

  14. Biomaterials in periodontal osseous defects

    PubMed Central

    Lal, Nand; Dixit, Jaya

    2012-01-01

    Introduction Osseous defects in periodontal diseases require osseous grafts and guided tissue regeneration (GTR) using barrier membranes. The present study was undertaken with the objectives to clinically evaluate the osteogenic potential of hydroxyapatite (HA), cissus quadrangularis (CQ), and oxidized cellulose membrane (OCM) and compare with normal bone healing. Materials and Methods Twenty subjects with periodontitis in the age group ranging from 20 years to 40 years were selected from our outpatient department on the basis of presence of deep periodontal pockets, clinical probing depth ≥5 mm, vertical osseous defects obvious on radiograph and two- or three-walled involvement seen on surgical exposure. Infrabony defects were randomly divided into four groups on the basis of treatment to be executed, such that each group comprised 5 defects. Group I was control, II received HA, III received CQ and IV received OCM. Probing depth and attachment level were measured at regular months after surgery. Defects were re-exposed using crevicular incisions at 6 months. Results There was gradual reduction in the mean probing pocket depth in all groups, but highly significant in the site treated with HA. Gain in attachment level was higher in sites treated with HA, 3.2 mm at 6 months. Conclusion Hydroxyapatite and OCM showed good reduction in pocket depth, attachment level gain and osseous defect fill. Further study should be conducted by using a combination of HA and OCM in periodontal osseous defects with growth factors and stem cells. PMID:25756030

  15. Aggression can be contagious: Longitudinal associations between proactive aggression and reactive aggression among young twins.

    PubMed

    Dickson, Daniel J; Richmond, Ashley D; Brendgen, Mara; Vitaro, Frank; Laursen, Brett; Dionne, Ginette; Boivin, Michel

    2015-01-01

    The present study examined sibling influence over reactive and proactive aggression in a sample of 452 same-sex twins (113 male dyads, 113 female dyads). Between and within siblings influence processes were examined as a function of relative levels of parental coercion and hostility to test the hypothesis that aggression contagion between twins occurs only among dyads who experience parental coerciveness. Teacher reports of reactive and proactive aggression were collected for each twin in kindergarten (M = 6.04 years; SD = 0.27) and in first grade (M = 7.08 years; SD = 0.27). Families were divided into relatively low, average, and relatively high parental coercion-hostility groups on the basis of maternal reports collected when the children were 5 years old. In families with relatively high levels of parental coercion-hostility, there was evidence of between-sibling influence, such that one twin's reactive aggression at age 6 predicted increases in the other twin's reactive aggression from ages 6 to 7, and one twin's proactive aggression at age 6 predicted increases in the other twin's proactive aggression from ages 6 to 7. There was also evidence of within-sibling influence such that a child's level of reactive aggression at age 6 predicted increases in the same child's proactive aggression at age 7, regardless of parental coercion-hostility. The findings provide new information about the etiology of reactive and proactive aggression and individual differences in their developmental interplay.

  16. Television viewing, aggression, and ethnicity.

    PubMed

    Harris, M B

    1992-02-01

    For 416 college students, questioned about their experiences with aggression and television viewing, only very weak correlations between preference for violent shows and aggression were observed. Black males watched significantly more television than other respondents. These findings suggest that the frequently reported correlation between viewing televised violence and aggression may not appear when sex, ethnicity, and education are controlled in a sample of young adults.

  17. Periodontal disease epidemiology - learned and unlearned?

    PubMed

    Baelum, Vibeke; López, Rodrigo

    2013-06-01

    The notion of periodontal disease being the major cause of tooth loss among adults was rooted in the focal infection paradigm that dominated the first half of the 20th century. This paradigm was established largely by personal opinions, and it was not until the development of periodontal indices in the mid-1950s that periodontal epidemiology gained momentum. Unfortunately, the indices used suffered from a number of flaws, whereby the interpretation of the research results took the form of circular reasoning. It was under this paradigm that therapeutic and preventive intervention for periodontal diseases became entirely devoted to oral hygiene, as poor oral hygiene and older age were understood to explain nearly all the variation in disease occurrence. In the early 1980s, studies appeared that contradicted the concepts of poor oral hygiene as the inevitable trigger of periodontitis and of linear and ubiquitous periodontitis progression, whereby periodontal epidemiology was led into a relatively short-lived high-risk era. At this time, it became evident that old scourges continue to haunt periodontology: the inability to agree in operational clinical criteria for a periodontitis diagnosis and the inability to devise both a meaningful and a useful classification of periodontal diseases based on nominalist principles. The meager outcome of the high-risk era led researchers to resurrect the focal infection paradigm, which is now dressed up as periodontal medicine. Unfortunately, these developments have left the core of periodontology somewhat disheveled and deserted.

  18. Cementum and Periodontal Ligament Regeneration.

    PubMed

    Menicanin, Danijela; Hynes, K; Han, J; Gronthos, S; Bartold, P M

    2015-01-01

    The unique anatomy and composition of the periodontium make periodontal tissue healing and regeneration a complex process. Periodontal regeneration aims to recapitulate the crucial stages of wound healing associated with periodontal development in order to restore lost tissues to their original form and function and for regeneration to occur, healing events must progress in an ordered and programmed sequence both temporally and spatially, replicating key developmental events. A number of procedures have been employed to promote true and predictable regeneration of the periodontium. Principally, the approaches are based on the use of graft materials to compensate for the bone loss incurred as a result of periodontal disease, use of barrier membranes for guided tissue regeneration and use of bioactive molecules. More recently, the concept of tissue engineering has been integrated into research and applications of regenerative dentistry, including periodontics, to aim to manage damaged and lost oral tissues, through reconstruction and regeneration of the periodontium and alleviate the shortcomings of more conventional therapeutic options. The essential components for generating effective cellular based therapeutic strategies include a population of multi-potential progenitor cells, presence of signalling molecules/inductive morphogenic signals and a conductive extracellular matrix scaffold or appropriate delivery system. Mesenchymal stem cells are considered suitable candidates for cell-based tissue engineering strategies owing to their extensive expansion rate and potential to differentiate into cells of multiple organs and systems. Mesenchymal stem cells derived from multiple tissue sources have been investigated in pre-clinical animal studies and clinical settings for the treatment and regeneration of the periodontium.

  19. Tissue engineering for periodontal regeneration.

    PubMed

    Kao, Richard T; Conte, Greg; Nishimine, Dee; Dault, Scott

    2005-03-01

    As a result of periodontal regeneration research, a series of clinical techniques have emerged that permit tissue engineering to be performed for more efficient regeneration and repair of periodontal defects and improved implant site development. Historically, periodontal regeneration research has focused on a quest for "magic filler" material. This search has led to the development of techniques utilizing autologous bone and bone marrow, allografts, xenografts, and various man-made bone substitutes. Though these techniques have had limited success, the desire for a more effective regenerative approach has resulted in the development of tissue engineering techniques. Tissue engineering is a relatively new field of reconstructive biology which utilizes mechanical, cellular, or biologic mediators to facilitate reconstruction/regeneration of a particular tissue. In periodontology, the concept of tissue engineering had its beginnings with guided tissue regeneration, a mechanical approach utilizing nonresorbable membranes to obtain regeneration in defects. In dental implantology, guided bone regeneration membranes +/- mechanical support are used for bone augmentation of proposed implant placement sites. With the availability of partially purified protein mixture from developing teeth and growth factors from recombinant technology, a new era of tissue engineering whereby biologic mediators can be used for periodontal regeneration. The advantage of recombinant growth factors is this tissue engineering device is consistent in its regenerative capacity, and variations in regenerative response are due to individual healing response and/or poor surgical techniques. In this article, the authors review how tissue engineering has advanced and discuss its impact on the clinical management of both periodontal and osseous defects in preparation for implant placement. An understanding of these new tissue engineering techniques is essential for comprehending today's ever

  20. Petrography of Lunar Meteorite LAP 02205, a New Low-Ti Basalt Possibly Launch Paired with NWA 032

    NASA Technical Reports Server (NTRS)

    Jolliff, B. L.; Zeigler, R. A.; Korotev, R. L.

    2004-01-01

    Lunar meteorite LAP 02205 is a 1.23 kg basalt collected during the 2002 field season in the La- Paz ice field, Antarctica [1]. We present a petrographic description including mineral modes and compositions, and the major-element composition of the bulk meteorite. LAP 02205 is an Fe-rich, moderately low-Ti mare basalt that is similar in composition, mineralogy, and mineral chemistry to the NWA 032 basaltic lunar meteorite. LAP 02205 is yet another of the moderately low- Ti basaltic meteorites that are underrepresented among Apollo and Luna samples but that appear from remote sensing to be the most common basalt type on the Moon.

  1. Periodontitis as an early presentation of HIV infection.

    PubMed Central

    Tenenbaum, H C; Mock, D; Simor, A E

    1991-01-01

    OBJECTIVE: To determine whether the presence of rapidly progressive periodontitis (RPP) in people at high risk for acquired immunodeficiency syndrome (AIDS) may be the first symptom of previously unrecognized human immunodeficiency virus (HIV) infection. DESIGN: Case series. SETTING: Dental clinic. PATIENTS: Twenty patients who presented or were referred to the dental clinic over 6 months for the treatment of unexplained RPP and were at high risk for AIDS. OUTCOME MEASURES: Diagnosis of HIV infection: identification of candidal organisms in cytologic smears, determination of complete and differential blood counts and of ratio between T4 (helper) and T8 (suppressor) lymphocytes, and performance of HIV antibody assays. MAIN RESULTS: All of the patients were men, although sex was not an inclusion criterion. Sixteen (80%) of the 20 patients were found to have HIV infection. Four had been aware that they were HIV positive: two admitted it only when their T4:T8 ratio was known and the other two when the T4:T8 test was explained or requested. Fifteen of the patients were homosexual, three came from AIDS-endemic areas, and two had hemophilia. The RPP was responsible for alveolar bone loss in all of the patients. One patient lost bone in one site because of localized osteomyelitis. Only five patients had concurrent candidal overgrowth, and three had Kaposi's sarcoma. The mean T4:T8 ratio was 0.57 (standard deviation 0.52). CONCLUSIONS: These findings suggest that periodontal disease may be one of the first clinical presentations of previously undiagnosed HIV infection. Thus, patients at high risk for AIDS who present with aggressive periodontal disease should be investigated for possible HIV infection. However, further, prospective studies are required to confirm the contention that RPP is one of the first signs of HIV infection or AIDS. Images Fig. 1 Fig. 2 Fig. 3 PMID:2025822

  2. Aggregatibacter actinomycetemcomitans, a potent immunoregulator of the periodontal host defense system and alveolar bone homeostasis.

    PubMed

    Herbert, B A; Novince, C M; Kirkwood, K L

    2016-06-01

    Aggregatibacter actinomycetemcomitans is a perio-pathogenic bacteria that has long been associated with localized aggressive periodontitis. The mechanisms of its pathogenicity have been studied in humans and preclinical experimental models. Although different serotypes of A. actinomycetemcomitans have differential virulence factor expression, A. actinomycetemcomitans cytolethal distending toxin (CDT), leukotoxin, and lipopolysaccharide (LPS) have been most extensively studied in the context of modulating the host immune response. Following colonization and attachment in the oral cavity, A. actinomycetemcomitans employs CDT, leukotoxin, and LPS to evade host innate defense mechanisms and drive a pathophysiologic inflammatory response. This supra-physiologic immune response state perturbs normal periodontal tissue remodeling/turnover and ultimately has catabolic effects on periodontal tissue homeostasis. In this review, we have divided the host response into two systems: non-hematopoietic and hematopoietic. Non-hematopoietic barriers include epithelium and fibroblasts that initiate the innate immune host response. The hematopoietic system contains lymphoid and myeloid-derived cell lineages that are responsible for expanding the immune response and driving the pathophysiologic inflammatory state in the local periodontal microenvironment. Effector systems and signaling transduction pathways activated and utilized in response to A. actinomycetemcomitans will be discussed to further delineate immune cell mechanisms during A. actinomycetemcomitans infection. Finally, we will discuss the osteo-immunomodulatory effects induced by A. actinomycetemcomitans and dissect the catabolic disruption of balanced osteoclast-osteoblast-mediated bone remodeling, which subsequently leads to net alveolar bone loss.

  3. Proteomics - The research frontier in periodontics.

    PubMed

    Gupta, Abhaya; Govila, Vivek; Saini, Ashish

    2015-01-01

    Periodontitis is an inflammatory condition resulting from the interplay between the infectious agents and host factors. Various protein molecules play a vital role in the initiation, progression and severity of periodontal diseases. The study of proteins as biomarkers in periodontal diseases has been highlighted during the last few years. In periodontitis multiple bacteria derived (e.g. collagen degrading enzymes, elastase like enzymes etc) and host derived mediators (eg. PGE2, TNF, IL1, IL6, MMP's etc) expressed in the saliva and gingival crevicular fluid, can be utilized as diagnostic markers for the disease. Another significant development regarding human genes and proteins has been the discovery of potential new drugs for the treatment of periodontal diseases. Therefore the information of the proteins involved in the pathogenesis of periodontal diseases can be utilized for its diagnosis, prevention and treatment.

  4. Associations between Periodontal Microbiota and Death Rates

    PubMed Central

    Chiu, Chung-Jung; Chang, Min-Lee; Taylor, Allen

    2016-01-01

    It is conceived that specific combinations of periodontal bacteria are associated with risk for the various forms of periodontitis. We hypothesized that such specificity is also related to human cause-specific death rates. We tested this hypothesis in a representative sample of the US population followed for a mean duration of 11 years and found that two specific patterns of 21 serum antibodies against periodontal bacteria were significantly associated with increased all-cause and/or diabetes-related mortalities. These data suggested that specific combinations of periodontal bacteria, even without inducing clinically significant periodontitis, may have a significant impact on human cause-specific death rates. Our findings implied that increased disease and mortality risk could be transmittable via the transfer of oral microbiota, and that developing personalized strategies and maintaining healthy oral microbiota beyond protection against periodontitis would be important to manage the risk. PMID:27748442

  5. Proteomics – The research frontier in periodontics

    PubMed Central

    Gupta, Abhaya; Govila, Vivek; Saini, Ashish

    2015-01-01

    Periodontitis is an inflammatory condition resulting from the interplay between the infectious agents and host factors. Various protein molecules play a vital role in the initiation, progression and severity of periodontal diseases. The study of proteins as biomarkers in periodontal diseases has been highlighted during the last few years. In periodontitis multiple bacteria derived (e.g. collagen degrading enzymes, elastase like enzymes etc) and host derived mediators (eg. PGE2, TNF, IL1, IL6, MMP's etc) expressed in the saliva and gingival crevicular fluid, can be utilized as diagnostic markers for the disease. Another significant development regarding human genes and proteins has been the discovery of potential new drugs for the treatment of periodontal diseases. Therefore the information of the proteins involved in the pathogenesis of periodontal diseases can be utilized for its diagnosis, prevention and treatment. PMID:25853048

  6. Periodontal Ligament Stem Cell-Mediated Treatment for Periodontitis in Miniature Swine

    PubMed Central

    Liu, Yi; Zheng, Ying; Ding, Gang; Fang, Dianji; Zhang, Chunmei; Bartold, Peter Mark; Gronthos, Stan; Shi, Songtao; Wang, Songlin

    2009-01-01

    Periodontitis is a periodontal tissue infectious disease and the most common cause for tooth loss in adults. It has been linked to many systemic disorders, such as coronary artery disease, stroke, and diabetes. At present, there is no ideal therapeutic approach to cure periodontitis and achieve optimal periodontal tissue regeneration. In this study, we explored the potential of using autologous periodontal ligament stem cells (PDLSCs) to treat periodontal defects in a porcine model of periodontitis. The periodontal lesion was generated in the first molars area of miniature pigs by the surgical removal of bone and subsequent silk ligament suture around the cervical portion of the tooth. Autologous PDLSCs were obtained from extracted teeth of the miniature pigs and then expanded ex vivo to enrich PDLSC numbers. When transplanted into the surgically created periodontal defect areas, PDLSCs were capable of regenerating periodontal tissues, leading to a favorable treatment for periodontitis. This study demonstrates the feasibility of using stem cell-mediated tissue engineering to treat periodontal diseases. PMID:18238856

  7. Reduction of Aggressive Behavior in the School.

    ERIC Educational Resources Information Center

    Petermann, Ulrike

    1988-01-01

    Discusses what may be considered aggressive behavior, what motivates aggressive students, and possible teacher responses to aggressive behavior. Describes four points on which teachers can focus to diminish the attractiveness of aggression and ensure that it is not rewarded. Identifies learning activities which provide aggressive students with the…

  8. The Effects of Pornography on Aggressive Behavior.

    ERIC Educational Resources Information Center

    Stacy, Lauri L.

    This document reviews existing empirical research on the effect of pornography on aggressive behavior. Two types of pornography are distinguished: aggressive pornography and non-aggressive pornography. Conclusions drawn from the research review are presented, including: (1) aggressive pornograpy consistently increases aggressive attitudes and…

  9. Periodontal management of patients with cardiovascular diseases.

    PubMed

    2002-08-01

    Periodontists are often called upon to provide periodontal therapy for patients with a variety of cardiovascular diseases. Safe and effective periodontal treatment requires a general understanding of the underlying cardiovascular diseases, their medical management, and necessary modifications to dental/periodontal therapy that may be required. In this informational paper more common cardiovascular disorders will be discussed and dental management considerations briefly described. This paper is intended for the use of periodontists and members of the dental profession.

  10. Emdogain--periodontal regeneration based on biomimicry.

    PubMed

    Gestrelius, S; Lyngstadaas, S P; Hammarström, L

    2000-06-01

    Biomimicry has been introduced as a term for innovations inspired by nature [1]. Such innovations may appear in almost every part of modern society. This review on the effects of enamel matrix proteins on the formation of cementum and the development of emdogain for regeneration of periodontal tissues lost due to periodontitis shows an example of biomimicry in dentistry. Findings from clinical and laboratory investigations are summarized and the biological basis for enamel matrix-induced periodontal regeneration is discussed.

  11. Lunar Influences on Human Aggression.

    ERIC Educational Resources Information Center

    Russell, Gordon W.; Dua, Manjula

    1983-01-01

    Used league records of all Canadian hockey games (N=426) played during a season to test a lunar-aggression hypothesis. Despite the use of multiple measures of lunar phase and interpersonal aggression, support for lunar influence was not forthcoming. Supplemental data revealed that beliefs in lunar influence are fairly common. (JAC)

  12. Traumatic Brain Injury and Aggression.

    ERIC Educational Resources Information Center

    Miller, Laurence

    1994-01-01

    Persons who have suffered traumatic injury to the brain may subsequently display aggressive behavior. Three main syndromes of aggression following traumatic brain injury are described: (1) episodic dyscontrol; (2) frontal lobe disinhibition; and (3) exacerbation of premorbid antisociality. The neuropsychological substrates of these syndromes are…

  13. [Modern approaches to periodontal microcirculatory parameters assessment].

    PubMed

    Krechina, E K; Smirnova, T N

    2017-01-01

    The article presents comprehensive functional study of periodontal tissues in 62 patients aged 20-45 with periodontal disease by laser Doppler flowmetry, Doppler ultrasound and computer capillaroscopy. All patients were divided into 5 groups depending on the severity of inflammation in the periodontium (chronic gingivitis, light, moderate and severe chronic periodontal disease). The relationship between microcirculatory indexes was evaluated by Pearson Product Moment Correlation or PPMC. The study shows high correlation between blood flow velocity measurement, diameter of microvessels and oxygen saturation in periodontal tissues that establish a direct relationship between studied parameters.

  14. Interaction between periodontitis and liver diseases

    PubMed Central

    Han, Pengyu; Sun, Dianxing; Yang, Jie

    2016-01-01

    Periodontitis is an oral disease that is highly prevalent worldwide, with a prevalence of 30–50% of the population in developed countries, but only ~10% present with severe forms. It is also estimated that periodontitis results in worldwide productivity losses amounting to ~54 billion USD yearly. In addition to the damage it causes to oral health, periodontitis also affects other types of disease. Numerous studies have confirmed the association between periodontitis and systemic diseases, such as diabetes, respiratory disease, osteoporosis and cardiovascular disease. Increasing evidence also indicated that periodontitis may participate in the progression of liver diseases, such as non-alcoholic fatty liver disease, cirrhosis and hepatocellular carcinoma, as well as affecting liver transplantation. However, to the best of our knowledge, there are currently no reviews elaborating upon the possible links between periodontitis and liver diseases. Therefore, the current review summarizes the human trials and animal experiments that have been conducted to investigate the correlation between periodontitis and liver diseases. Furthermore, in the present review, certain mechanisms that have been postulated to be responsible for the role of periodontitis in liver diseases (such as bacteria, pro-inflammatory mediators and oxidative stress) are considered. The aim of the review is to introduce the hypothesis that periodontitis may be important in the progression of liver disease, thus providing dentists and physicians with an improved understanding of this issue. PMID:27588170

  15. Regeneration of periodontal tissues: guided tissue regeneration.

    PubMed

    Villar, Cristina C; Cochran, David L

    2010-01-01

    The concept that only fibroblasts from the periodontal ligament or undifferentiated mesenchymal cells have the potential to re-create the original periodontal attachment has been long recognized. Based on this concept, guided tissue regeneration has been applied with variable success to regenerate periodontal defects. Quantitative analysis of clinical outcomes after guided tissue regeneration suggests that this therapy is a successful and predictable procedure to treat narrow intrabony defects and class II mandibular furcations, but offers limited benefits in the treatment of other types of periodontal defects.

  16. Somatic stem cell biology and periodontal regeneration.

    PubMed

    Zhu, Bin; Liu, Yihan; Li, Dehua; Jin, Yan

    2013-01-01

    Somatic stem cells have been acknowledged for their ability to differentiate into multiple cell types and their capacity for self-renewal. Some mesenchymal stem cells play a dominant role in the repair and reconstruction of periodontal tissues. Both dental-derived and some non-dental-derived mesenchymal stem cells possess the capacity for periodontal regeneration under certain conditions with induced differentiation, proliferation, cellular secretion, and their interactions. Stem cell-based tissue engineering technology promises to bring improvements to periodontal regeneration, biologic tooth repair, and bioengineered implants. The present review discusses the roles and values of various somatic stem cells in periodontal regeneration.

  17. The Neurobiology of Impulsive Aggression.

    PubMed

    Blair, Robert J R

    2016-02-01

    This selective review provides a model of the neurobiology of impulsive aggression from a cognitive neuroscience perspective. It is argued that prototypical cases of impulsive aggression, those associated with anger, involve the recruitment of the acute threat response system structures; that is, the amygdala, hypothalamus, and periaqueductal gray. It is argued that whether the recruitment of these structures results in impulsive aggression or not reflects the functional roles of ventromedial frontal cortex and dorsomedial frontal and anterior insula cortex in response selection. It is also argued that impulsive aggression may occur because of impaired decision making. The aggression may not be accompanied by anger, but it will reflect disrupted evaluation of the rewards/benefits of the action.

  18. The Neurobiology of Impulsive Aggression

    PubMed Central

    2016-01-01

    Abstract This selective review provides a model of the neurobiology of impulsive aggression from a cognitive neuroscience perspective. It is argued that prototypical cases of impulsive aggression, those associated with anger, involve the recruitment of the acute threat response system structures; that is, the amygdala, hypothalamus, and periaqueductal gray. It is argued that whether the recruitment of these structures results in impulsive aggression or not reflects the functional roles of ventromedial frontal cortex and dorsomedial frontal and anterior insula cortex in response selection. It is also argued that impulsive aggression may occur because of impaired decision making. The aggression may not be accompanied by anger, but it will reflect disrupted evaluation of the rewards/benefits of the action. PMID:26465707

  19. False memories for aggressive acts.

    PubMed

    Laney, Cara; Takarangi, Melanie K T

    2013-06-01

    Can people develop false memories for committing aggressive acts? How does this process compare to developing false memories for victimhood? In the current research we used a simple false feedback procedure to implant false memories for committing aggressive acts (causing a black eye or spreading malicious gossip) or for victimhood (receiving a black eye). We then compared these false memories to other subjects' true memories for equivalent events. False aggressive memories were all too easy to implant, particularly in the minds of individuals with a proclivity towards aggression. Once implanted, the false memories were indistinguishable from true memories for the same events, on several dimensions, including emotional content. Implications for aggression-related memory more generally as well as false confessions are discussed.

  20. Grinding and polishing technology by computer controlled active lap for Φ1250mmF/1.5 aspheric mirror

    NASA Astrophysics Data System (ADS)

    Fan, Bin; Zeng, Zhige; Li, Xiaojin; Chen, Qiang; Gao, Pingqi; Zhou, Jiabin; Wan, Yongjian

    2010-05-01

    For large aspheric optical elements, Computer Controlled Active Lap(CCAL) manufacturing which developed in IOE (Institute of Optics and Electronics, Chinese Academy of Science), have some advantages such as higher manufacturing efficiency, lower middle-frequency and high-frequency errors comparing the fixed lapping technology and CCOS(Computer Controlled Optical Surface) technology. A paraboloid surface of Φ1250mmF/1.5 was grinded by the active lap bonded with ceramic pills, as well as polished will pitch bonded active lap. During polishing processing a null lens was designed to test the paraboloid surface, the final testing data of RMS with ZYGO interferometer reached to 0.027λ(λ=0.6328μm).

  1. Beliefs about aggression moderate alcohol's effects on aggression.

    PubMed

    Levinson, Cheri A; Giancola, Peter R; Parrott, Dominic J

    2011-02-01

    The goal of this investigation was to determine whether permissive beliefs about aggression moderate the relation between acute alcohol intoxication and aggression in two large experiments. Participants in Study 1 were 328 (163 men and 165 women) social drinkers and those in Study 2 were 518 (252 men and 266 women) social drinkers. Beliefs about aggression were assessed using a well-validated self-report measure. Following the consumption of either an alcohol or a placebo beverage, participants were tested on a laboratory task in which electric shocks were received from, and administered to, a fictitious opponent under the guise of a competitive reaction-time task. Aggression was operationalized as the combined mean responses for shock intensity and duration across all trials. Our central finding was that alcohol increased aggression in persons with more approving beliefs about aggression than in those who did not hold such beliefs. Our results are discussed within the context of Huesmann's (1988) cognitive script model of aggression. Suggestions for violence prevention efforts are put forth as well.

  2. Investigation of defect rate of lap laser welding of stainless steel railway vehicles car body

    NASA Astrophysics Data System (ADS)

    Wang, Hongxiao

    2015-02-01

    In order to resolve the disadvantages such as poor appearance quality, poor tightness, low efficiency of resistance spot welding of stainless steel rail vehicles, partial penetration lap laser welding process was investigated widely. But due to the limitation of processing technology, there will be local incomplete fusion in the lap laser welding seam. Defect rate is the ratio of the local incomplete fusion length to the weld seam length. The tensile shear strength under different defect rate and its effect on the car body static strength are not clear. It is necessary to find the biggest defect rate by numerical analysis of effects of different defect rates on the laser welding stainless steel rail vehicle body structure strength ,and tests of laser welding shear tensile strength.

  3. Ground based experiments on the growth and characterization of L-Arginine Phosphate (LAP) crystals

    NASA Technical Reports Server (NTRS)

    Rao, S. M.; Cao, C.; Batra, A. K.; Lal, R. B.; Mookherji, T. K.

    1991-01-01

    L-Arginine Phosphate (LAP) is a new nonlinear optical material with higher efficiency for harmonic generation compared to KDP. Crystals of LAP were grown in the laboratory from supersaturated solutions by temperature lowering technique. Investigations revealed the presence of large dislocation densities inside the crystals which are observed to produce refractive index changes causing damage at high laser powers. This is a result of the convection during crystal growth from supersaturated solutions. It is proposed to grow these crystals in a diffusion controlled growth condition under microgravity environment and compare the crystals grown in space with those grown on ground. Physical properties of the solutions needed for modelling of crystal growth are also presented.

  4. A Practical Engineering Approach to Predicting Fatigue Crack Growth in Riveted Lap Joints

    NASA Technical Reports Server (NTRS)

    Harris, Charles E.; Piascik, Robert S.; Newman, James C., Jr.

    1999-01-01

    An extensive experimental database has been assembled from very detailed teardown examinations of fatigue cracks found in rivet holes of fuselage structural components. Based on this experimental database, a comprehensive analysis methodology was developed to predict the onset of widespread fatigue damage in lap joints of fuselage structure. Several computer codes were developed with specialized capabilities to conduct the various analyses that make up the comprehensive methodology. Over the past several years, the authors have interrogated various aspects of the analysis methods to determine the degree of computational rigor required to produce numerical predictions with acceptable engineering accuracy. This study led to the formulation of a practical engineering approach to predicting fatigue crack growth in riveted lap joints. This paper describes the practical engineering approach and compares predictions with the results from several experimental studies.

  5. A laboratory study of fracture in the presence of lap splice multiple site damage

    NASA Astrophysics Data System (ADS)

    Mayville, Ronald A.; Warren, Thomas J.

    Flat coupons were tested in the laboratory to determine a fracture criterion for link-up of fuselage lap splice multiple site damage at adjacent rivet holes. Experiments were performed on 0.040 inch (1 mm) thick 2024-T3 clad aluminum sheet. Continuous and riveted lap splice coupons were tested with simulated uniform (equal crack lengths) and nonuniform MSD, and the effects of notch sharpness were also studied. A net section stress criterion was found to provide excellent predictions of fracture for uniform MSD and uniform stress distributions. This same criterion provides conservative predictions for nonuniform MSD in uniform stress fields. An overload/cyclic stress experiment was also conducted to explore the pressurized proof test scenario of ensuring structural integrity.

  6. Fatigue crack initiation in riveted lap joints and in pressurized fuselages

    NASA Astrophysics Data System (ADS)

    Mueller, Richard P. G.

    1993-06-01

    Riveted joints in pressurized fuselages are exposed to severe fatigue loading. The study was carried out to increase fundamental understanding of the behavior of riveted fuselage joints. Areas of interest include rivet flexibility, load transfer, residual stress distribution, fatigue crack location, secondary bending and inter-sheet friction. These aspects depend on the squeezing force used to drive the rivet. Flat uniaxially loaded riveted lap joint specimens show longer fatigue lives than curved riveted panels loaded by internal pressure in a barrel test setup. Strain gauge measurements on a barrel test setup show more severe loading of the non-countersunk inner sheet compared to the countersunk outer sheet. Finite element calculations gave insight to the improved fatigue crack initiation performance for increased sqeezing force and to the crack initiation location. The early crack initiation at the edges of flat riveted lap joint panels is explained.

  7. A Practical Engineering Approach to Predicting Fatigue Crack Growth in Riveted Lap Joints

    NASA Technical Reports Server (NTRS)

    Harris, C. E.; Piascik, R. S.; Newman, J. C., Jr.

    2000-01-01

    An extensive experimental database has been assembled from very detailed teardown examinations of fatigue cracks found in rivet holes of fuselage structural components. Based on this experimental database, a comprehensive analysis methodology was developed to predict the onset of widespread fatigue damage in lap joints of fuselage structure. Several computer codes were developed with specialized capabilities to conduct the various analyses that make up the comprehensive methodology. Over the past several years, the authors have interrogated various aspects of the analysis methods to determine the degree of computational rigor required to produce numerical predictions with acceptable engineering accuracy. This study led to the formulation of a practical engineering approach to predicting fatigue crack growth in riveted lap joints. This paper describes the practical engineering approach and compares predictions with the results from several experimental studies.

  8. Performance evaluation of pitch lap in correcting mid-spatial-frequency errors under different smoothing parameters

    NASA Astrophysics Data System (ADS)

    Xu, Lichao; Wan, Yongjian; Liu, Haitao; Wang, Jia

    2016-10-01

    Smoothing is a convenient and efficient way to restrain middle spatial frequency (MSF) errors. Based on the experience, lap diameter, rotation speed, lap pressure and the hardness of pitch layer are important to correcting MSF errors. Therefore, nine groups of experiments are designed with the orthogonal method to confirm the significance of the above parameters. Based on the Zhang's model, PV (Peak and Valley) and RMS (Root Mean Square) versus processing cycles are analyzed before and after smoothing. At the same time, the smoothing limit and smoothing rate for different parameters to correct MSF errors are analyzed. Combined with the deviation analysis, we distinguish between dominant and subordinate parameters, and find out the optimal combination and law of various parameters, so as to guide the further research and fabrication.

  9. Analysis of interface cracks in adhesively bonded lap shear joints, part 4

    NASA Technical Reports Server (NTRS)

    Wang, S. S.; Yau, J. F.

    1981-01-01

    Conservation laws of elasticity for nonhomogeneous materials were developed and were used to study the crack behavior in adhesively bonded lap shear joints. By using these laws and the fundamental relationships in fracture mechanics of interface cracks, the problem is reduced to a pair of linear algebraic equations, and stress intensity solutions can be determined directly by information extracted from the far field. The numerical results obtained show that: (1) in the lap-shear joint with a given adherend, the opening-mode stress intensity factor, (K sub 1) is always larger than that of the shearing-mode (K sub 2); (2) (K sub 1) is not sensitive to adherent thickness abut (K sub 2) increases rapidly with increasing thickness; and (3) (K sub 1) and (K sub 2) increase simultaneously as the interfacial crack length increases.

  10. Material characterization of structural adhesives in the lap shear mode. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Schenck, S. C.; Sancaktar, E.

    1983-01-01

    A general method for characterizing structural adhesives in the bonded lap shear mode is proposed. Two approaches in the form of semi-empirical and theoretical approaches are used. The semi-empirical approach includes Ludwik's and Zhurkov's equations to describe respectively, the failure stresses in the constant strain rate and constant stress loading modes with the inclusion of the temperature effects. The theoretical approach is used to describe adhesive shear stress-strain behavior with the use of viscoelastic or nonlinear elastic constitutive equations. Three different model adhesives are used in the simple lap shear mode with titanium adherends. These adhesives (one of which was developed at NASA Langley Research Center) are currently considered by NASA for possible aerospace applications. Use of different model adhesives helps in assessment of the generality of the method.

  11. Modeling the Influence of Stitching on Delamination Growth in Stitched Warp-Knit Composite Lap Joints

    NASA Technical Reports Server (NTRS)

    Glaessgen, E. H.; Raju, I. S.; Poe, C. C., Jr.

    1999-01-01

    The effect of stitches on the failure of a single lap joint configuration was determined in a combined experimental and analytical study. The experimental study was conducted to determine debond growth under static monotonic loading. The stitches were shown to delay the initiation of the debond and provide load transfer beyond the load necessary to completely debond the stitched lap joint. The strain energy release rates at the debond front were calculated using a finite element-based technique. Models of the unstitched configuration showed significant values of modes I and II across the width of the joint and showed that mode III is zero at the centerline but increases near the free edge. Models of the stitched configuration showed that the stitches effectively reduced mode I to zero, but had less of an effect on modes II and III.

  12. Parameter on chronic periodontitis with advanced loss of periodontal support. American Academy of Periodontology.

    PubMed

    2000-05-01

    The American Academy of Periodontology has developed the following parameter on the treatment of chronic periodontitis with advanced loss of periodontal supporting tissues. Patients should be informed of the disease process, therapeutic alternatives, potential complications, expected results, and their responsibility in treatment. Consequences of no treatment should be explained. Failure to appropriately treat chronic periodontitis can result in progressive loss of periodontal supporting tissues, an adverse change in prognosis, and could result in tooth loss. Given this information, patients should then be able to make informed decisions regarding their periodontal therapy.

  13. Parameter on chronic periodontitis with slight to moderate loss of periodontal support. American Academy of Periodontology.

    PubMed

    2000-05-01

    The American Academy of Periodontology has developed the following parameter on the treatment of chronic periodontitis with slight to moderate loss of periodontal supporting tissues. Patients should be informed of the disease process, therapeutic alternatives, potential complications, expected results, and their responsibility in treatment. Consequences of no treatment should be explained. Failure to appropriately treat chronic periodontitis can result in progressive loss of periodontal supporting tissues, an adverse change in prognosis, and could result in tooth loss. Given this information, patients should then be able to make informed decisions regarding their periodontal therapy.

  14. Aggressive Erotica and Violence against Women.

    ERIC Educational Resources Information Center

    Donnerstein, Edward

    1980-01-01

    Examines the effects of aggressive-erotic stimuli on male aggression toward females. Male subjects' deliveries of electric shocks to males or females after viewing either a neutral, erotic, or aggressive-erotic film were measured. (Author/SS)

  15. Periodontal tissue disposition of azithromycin.

    PubMed

    Malizia, T; Tejada, M R; Ghelardi, E; Senesi, S; Gabriele, M; Giuca, M R; Blandizzi, C; Danesi, R; Campa, M; Del Tacca, M

    1997-12-01

    The tissue penetration of azithromycin, the prototype of a new class of macrolide antibiotics named azalides, was studied in patients undergoing surgery for third-molar removal. Drug concentrations in plasma, saliva, and periodontal tissues were evaluated in 28 patients treated with azithromycin 500 mg/day per os for 3 consecutive days. Samples of blood, saliva, gingiva, and alveolar bone were collected during oral surgery, 12 hours, and 2.5, 4.5, and 6.5 days after the last dosing, and the azithromycin concentration was measured microbiologically by using Micrococcus luteus NCTC 8440 as the reference organism. The highest concentrations of azithromycin were observed 12 hours after the last dose in plasma, saliva, gingiva, and bone (0.33 +/- 0.04 mg/l, 2.14 +/- 0.30 mg/l, 6.47 +/- 0.57 mg/kg, and 1.86 +/- 0.15 mg/kg, respectively) and then declined gradually. However, consistent levels of the drug in saliva and periodontal tissues could be detected up to 6.5 days, indicating that azithromycin was retained in target tissues and fluids for a long time after the end of treatment. Among the samples examined, the highest concentration of azithromycin was found in the gingiva at each time studied. Moreover, the ratios of salivary or periodontal tissue levels versus plasma concentrations remained nearly unmodified from 12 hours up to 6.5 days. Overall, these results indicate a favorable disposition of azithromycin into saliva and periodontal tissues and suggest that this macrolide antibiotic represents a valuable option in the pharmacologic treatment of odontogenic infections.

  16. A Single-Lap Joint Adhesive Bonding Optimization Method Using Gradient and Genetic Algorithms

    NASA Technical Reports Server (NTRS)

    Smeltzer, Stanley S., III; Finckenor, Jeffrey L.

    1999-01-01

    A natural process for any engineer, scientist, educator, etc. is to seek the most efficient method for accomplishing a given task. In the case of structural design, an area that has a significant impact on the structural efficiency is joint design. Unless the structure is machined from a solid block of material, the individual components which compose the overall structure must be joined together. The method for joining a structure varies depending on the applied loads, material, assembly and disassembly requirements, service life, environment, etc. Using both metallic and fiber reinforced plastic materials limits the user to two methods or a combination of these methods for joining the components into one structure. The first is mechanical fastening and the second is adhesive bonding. Mechanical fastening is by far the most popular joining technique; however, in terms of structural efficiency, adhesive bonding provides a superior joint since the load is distributed uniformly across the joint. The purpose of this paper is to develop a method for optimizing single-lap joint adhesive bonded structures using both gradient and genetic algorithms and comparing the solution process for each method. The goal of the single-lap joint optimization is to find the most efficient structure that meets the imposed requirements while still remaining as lightweight, economical, and reliable as possible. For the single-lap joint, an optimum joint is determined by minimizing the weight of the overall joint based on constraints from adhesive strengths as well as empirically derived rules. The analytical solution of the sin-le-lap joint is determined using the classical Goland-Reissner technique for case 2 type adhesive joints. Joint weight minimization is achieved using a commercially available routine, Design Optimization Tool (DOT), for the gradient solution while an author developed method is used for the genetic algorithm solution. Results illustrate the critical design variables

  17. Low frequency ultrasonic nondestructive inspection of aluminum/adhesive fuselage lap splices

    SciTech Connect

    Patton, Thadd

    1994-01-04

    This thesis is a collection of research efforts in ultrasonics, conducted at the Center for Aviation Systems Reliability located at Iowa State University, as part of the Federal Aviation Administration`s ``Aging Aircraft Program.`` The research was directed toward the development of an ultrasonic prototype to inspect the aluminum/adhesive fuselage lap splices found on 1970`s vintage Boeing passenger aircraft. The ultrasonic prototype consists of a normal incidence, low frequency inspection technique, and a scanning adapter that allows focused immersion transducers to be operated in a direct contact manner in any inspection orientation, including upside-down. The inspection technique uses a computer-controlled data acquisition system to produce a C-scan image of a radio frequency (RF) waveform created by a low frequency, broadband, focused beam transducer, driven with a spike voltage pulser. C-scans produced by this technique are color representations of the received signal`s peak-to-peak amplitude (voltage) taken over an (x, y) grid. Low frequency, in this context, refers to a wavelength that is greater than the lap splice`s layer thicknesses. With the low frequency technique, interface echoes of the lap splice are not resolved and gating of the signal is unnecessary; this in itself makes the technique simple to implement and saves considerable time in data acquisition. Along with the advantages in data acquisition, the low frequency technique is relatively insensitive to minor surface curvature and to ultrasonic interference effects caused by adhesive bondline thickness variations in the lap splice.

  18. Light-Addressable Potentiometric (LAP) Sensor Assay of Newcastle Disease Virus

    DTIC Science & Technology

    1991-04-01

    potentiometric (LAP) sensor, was employed to detect the presence of immobilized urease -conjugated antibodies. Lower limits of detection (LOD) of the assay were...is high, approximately 95% under the conditions of these assays (8), the number of the urease -containing antibody-antigen sandwiches immobilized will...produced un- der DND contract by the University of Alberta (Edmonton, AB). Antibody from clone 25R5 was covalently linked to urease ; antibody from clone

  19. Evaluation of the fuselage lap joint fatigue and terminating action repair

    NASA Astrophysics Data System (ADS)

    Samavedam, Gopal; Thomson, Douglas; Jeong, David Y.

    1994-09-01

    Terminating action is a remedial repair which entails the replacement of shear head countersunk rivets with universal head rivets which have a larger shank diameter. The procedure was developed to eliminate the risk of widespread fatigue damage (WFD) in the upper rivet row of a fuselage lap joint. A test and evaluation program has been conducted by Foster-Miller, Inc. (FMI) to evaluate the terminating action repair of the upper rivet row of a commercial aircraft fuselage lap splice. Two full scale fatigue tests were conducted on fuselage panels using the growth of fatigue cracks in the lap joint. The second test was performed to evaluate the effectiveness of the terminating action repair. In both tests, cyclic pressurization loading was applied to the panels while crack propagation was recorded at all rivet locations at regular intervals to generate detailed data on conditions of fatigue crack initiation, ligament link-up, and fuselage fracture. This program demonstrated that the terminating action repair substantially increases the fatigue life of a fuselage panel structure and effectively eliminates the occurrence of cracking in the upper rivet row of the lap joint. While high cycle crack growth was recorded in the middle rivet row during the second test, failure was not imminent when the test was terminated after cycling to well beyond the service life. The program also demonstrated that the initiation, propagation, and linkup of WFD in full-scale fuselage structures can be simulated and quantitatively studied in the laboratory. This paper presents an overview of the testing program and provides a detailed discussion of the data analysis and results. Crack distribution and propagation rates and directions as well as frequency of cracking are presented for both tests. The progression of damage to linkup of adjacent cracks and to eventual overall panel failure is discussed. In addition, an assessment of the effectiveness of the terminating action repair and the

  20. Evaluation of the fuselage lap joint fatigue and terminating action repair

    NASA Technical Reports Server (NTRS)

    Samavedam, Gopal; Thomson, Douglas; Jeong, David Y.

    1994-01-01

    Terminating action is a remedial repair which entails the replacement of shear head countersunk rivets with universal head rivets which have a larger shank diameter. The procedure was developed to eliminate the risk of widespread fatigue damage (WFD) in the upper rivet row of a fuselage lap joint. A test and evaluation program has been conducted by Foster-Miller, Inc. (FMI) to evaluate the terminating action repair of the upper rivet row of a commercial aircraft fuselage lap splice. Two full scale fatigue tests were conducted on fuselage panels using the growth of fatigue cracks in the lap joint. The second test was performed to evaluate the effectiveness of the terminating action repair. In both tests, cyclic pressurization loading was applied to the panels while crack propagation was recorded at all rivet locations at regular intervals to generate detailed data on conditions of fatigue crack initiation, ligament link-up, and fuselage fracture. This program demonstrated that the terminating action repair substantially increases the fatigue life of a fuselage panel structure and effectively eliminates the occurrence of cracking in the upper rivet row of the lap joint. While high cycle crack growth was recorded in the middle rivet row during the second test, failure was not imminent when the test was terminated after cycling to well beyond the service life. The program also demonstrated that the initiation, propagation, and linkup of WFD in full-scale fuselage structures can be simulated and quantitatively studied in the laboratory. This paper presents an overview of the testing program and provides a detailed discussion of the data analysis and results. Crack distribution and propagation rates and directions as well as frequency of cracking are presented for both tests. The progression of damage to linkup of adjacent cracks and to eventual overall panel failure is discussed. In addition, an assessment of the effectiveness of the terminating action repair and the

  1. Seismic fragility analysis of lap-spliced reinforced concrete columns retrofitted by SMA wire jackets

    NASA Astrophysics Data System (ADS)

    Choi, Eunsoo; Park, Sun-Hee; Chung, Young-Soo; Kim, Hee Sun

    2013-08-01

    The aim of this study is to provide seismic fragility curves of reinforced concrete columns retrofitted by shape memory alloy wire jackets and thus assess the seismic performance of the columns against earthquakes, comparing them with reinforced concrete columns with lap-spliced and continuous reinforcement. For that purpose, this study first developed analytical models of the experimental results of the three types of columns, (1) lap-spliced reinforcement, (2) continuous reinforcement and (3) lap-spliced reinforcement and retrofitted by SMA wire jackets, using the OpenSEES program, which is oriented to nonlinear dynamic analysis. Then, a suite of ten recorded ground motions was used to conduct dynamic analyses of the analytical models with scaling of the peak ground acceleration from 0.1g to 1.0g in steps of 0.1g. From the static experimental tests, the column retrofitted with SMA wire jackets had a larger displacement ductility by a factor of 2.3 times that of the lap-spliced column, which was 6% larger compared with the ductility of the continuous reinforcement column. From the fragility analyses, the SMA wire jacketed column had median values of 0.162g and 0.567g for yield and collapse, respectively. For the yield damage state, the SMA wire jacketed column had a median value similar to the continuous reinforcement column. However, for the complete damage state, the SMA wire jacketed column showed a 1.33 times larger median value than the continuously reinforcement column.

  2. Effect of Welding Speed on Joint Features and Lap Shear Properties of Stationary Shoulder FSLWed Alclad 2024 Al Alloy

    NASA Astrophysics Data System (ADS)

    Xu, Zhiwu; Li, Zhengwei; Lv, Zan; Zhang, Liguo

    2017-02-01

    Using alclad 2024-T4 aluminum alloy as the research object, stationary shoulder technology was used in friction stir lap welding process to investigate its performance in this study. Joint features and mechanical properties of the lap joints were mainly investigated. Results show that lap joint with smooth surface, without shoulder marks and inner defects can be obtained using the stationary shoulder technology. With increasing the welding speed from 40 to 130 mm/min, effective sheet thickness (EST) at the advancing side (AS) shows rather stable values (from 1.17 to 1.31 mm), EST at the retreating side (RS) increases from 0.57 to 1.13 mm, and stir zone width decreases from 4.95 to 4.44 mm. Lap shear failure load of the SSFSLW joints firstly increases and then decreases with increasing the welding speed. Using 100 mm/min, the maximum failure loads of 15.85 and 9.01 kN were obtained when the RS and AS of the joint bear the main load during the lap shear test. Shear fracture mode and tensile fracture mode can be obtained during the lap shear test. All joints present ductile fracture mode.

  3. Effect of Welding Speed on Joint Features and Lap Shear Properties of Stationary Shoulder FSLWed Alclad 2024 Al Alloy

    NASA Astrophysics Data System (ADS)

    Xu, Zhiwu; Li, Zhengwei; Lv, Zan; Zhang, Liguo

    2017-03-01

    Using alclad 2024-T4 aluminum alloy as the research object, stationary shoulder technology was used in friction stir lap welding process to investigate its performance in this study. Joint features and mechanical properties of the lap joints were mainly investigated. Results show that lap joint with smooth surface, without shoulder marks and inner defects can be obtained using the stationary shoulder technology. With increasing the welding speed from 40 to 130 mm/min, effective sheet thickness (EST) at the advancing side (AS) shows rather stable values (from 1.17 to 1.31 mm), EST at the retreating side (RS) increases from 0.57 to 1.13 mm, and stir zone width decreases from 4.95 to 4.44 mm. Lap shear failure load of the SSFSLW joints firstly increases and then decreases with increasing the welding speed. Using 100 mm/min, the maximum failure loads of 15.85 and 9.01 kN were obtained when the RS and AS of the joint bear the main load during the lap shear test. Shear fracture mode and tensile fracture mode can be obtained during the lap shear test. All joints present ductile fracture mode.

  4. Periodontal Proteomics: Wonders Never Cease!

    PubMed Central

    Grover, Harpreet Singh; Kapoor, Shalini; Saksena, Neha

    2013-01-01

    Proteins are vital parts of living organisms, as they are integral components of the physiological metabolic pathways of cells. Periodontal tissues comprise multicompartmental groups of interacting cells and matrices that provide continuous support, attachment, proprioception, and physical protection for the teeth. The proteome map, that is, complete catalogue of the matrix and cellular proteins expressed in alveolar bone, cementum, periodontal ligament, and gingiva, is to be explored for more in-depth understanding of periodontium. The ongoing research to understand the signalling pathways that allow cells to divide, differentiate, and die in controlled manner has brought us to the era of proteomics. Proteomics is defined as the study of all proteins including their relative abundance, distribution, posttranslational modifications, functions, and interactions with other macromolecules, in a given cell or organism within a given environment and at a specific stage in the cell cycle. Its application to periodontal science can be used to monitor health status, disease onset, treatment response, and outcome. Proteomics can offer answers to critical, unresolved questions such as the biological basis for the heterogeneity in gingival, alveolar bone, and cemental cell populations. PMID:24490073

  5. [The effect of media violence on aggression: is aggressive behavior mediated by aggressive cognitions and emotions?].

    PubMed

    Yukawa, S; Yoshida, F

    1999-06-01

    This study investigated whether cognitions and emotions elicited by media violence mediate aggressive behavior. Eighty undergraduates, 40 men and 40 women, participated in the experiment. First, subjects were exposed to one of four violent videos which varied in levels of violence and entertainment. Subjects' heart rate and eyeblink rate were continuously recorded while they watched the video. After watching it, subjects described their thoughts which occurred while watching it and rated their affective reactions to it. Finally, their aggressive behavior was measured. Results showed that (1) videos high in violence elicited more aggressive thoughts, more thoughts of negative affect, stronger negative affects, and stronger empty-powerless affects, whereas videos high in entertainment elicited stronger positive affects; (2) no significant differences were found among the videos in terms of physiological reactions and aggressive behavior; and (3) cognitions and emotions elicited by media violence did not mediate aggressive behavior.

  6. MMP-8 Expression in Periodontal Tissues Surgically Removed from Diabetic and Nondiabetic Patients with Periodontal Disease

    PubMed Central

    Hardy, Douglas C.; Ross, Jonathan H.; Schuyler, Corinne A.; Leite, Renata S.; Slate, Elizabeth H.; Huang, Yan

    2011-01-01

    Background Although it is known that periodontal MMP-8 expression is associated with periodontal disease, the information concerning the periodontal MMP-8 expression in diabetic patients with periodontal disease is insufficient. Materials and Methods Periodontal tissue specimens were collected from 7 patients without periodontal disease and diabetes (Group 1), 15 patients with periodontal disease alone (Group 2) and 10 patients with both periodontal disease and diabetes (Group 3). The frozen sections were prepared and MMP-8 protein expression was detected using immunohistochemistry and quantified. For in vitro study, human U937 mononuclear cells were pre-exposed to normal or high glucose and then treated with LPS. Results The nonparametric Kruskal-Wallis test showed that the difference in MMP-8 protein levels among the three groups were statistically significant (p = 0.003). Nonparametric analysis using Jonckheere-Terpstra test showed a tendency of increase in periodontal MMP-8 levels across Group 1 to Group 2 to Group 3 (p = 0.0002). In vitro studies showed that high glucose and LPS had a synergistic effect on MMP-8 expression. Conclusion Our current study showed an increasing trend in MMP-8 protein expression levels across patients without both periodontal disease and diabetes, patients with periodontal disease alone and patients with both diseases. PMID:22092744

  7. Impact of Periodontal Intervention on Local inflammation, Periodontitis and HIV Outcomes

    PubMed Central

    Valentine, J.; Sanders, A E; Saladyanant, T; Ramsey, K; Blake, J; Morelli, T; Southerland, J; Quinlivan, E B; Nelson, J; DeParis, K; Webster-Cyriaque, J

    2016-01-01

    Objective Periodontal disease resolution was hypothesized to impact systemic HIV measures. Methods In this longitudinal cohort study, 73 HIV-positive subjects received comprehensive dental care. AAP, CDC/AAP and biofilm gingival interface case definitions determined periodontal classification. In a subset, IL-6 was measured. Multivariable binary logistic regression models estimated odds of periodontitis development for comparisons between HIV and NHANES (2009–12) groups. Results In both groups, moderate/severe periodontitis was positively associated with non-white race, smoking, male gender, low income and increased pro-inflammatory cytokines. Likelihood of HIV periodontitis was higher across demographic variables. Subjects with severe periodontitis on antiretroviral therapy demonstrated high plasma viral loads at baseline (median= 464 co/ml; mean 65,773 co/ml). Post intervention, HIV periodontitis distribution became similar to NHANES and IL-6 levels decreased 2-fold (p=0.07). Subjects with suppressed viral load at baseline demonstrated increased CD4 counts at 12 months post intervention (P=0.027) (n=26). Conclusions Smoking, being non-white and low income were associated with periodontitis in HIV and NHANES. Higher Il-6, higher HIV VL and lower CD4 were associated with moderate/severe periodontal disease. Periodontitis decreased significantly with treatment producing periodontal profiles mirroring the national norm. In a subset of suppressed subjects, decreased oral inflammation, and associated microbial translocation, yielded improved CD4 counts. PMID:27109277

  8. Behavior Of A Confined Tension Lap Splice In High-Strength Reinforced Concrete Beams

    NASA Astrophysics Data System (ADS)

    Abdel-Kareem, Ahmed H.; Abousafa, Hala; El-Hadidi, Omaia S.

    2015-09-01

    The results of an experimental program conducted on seventeen simply supported concrete beams to study the effect of transverse reinforcement on the behavior of the lap splice of a steel reinforcement in tension zones in high-strength concrete beams are presented. The parameters included in the experimental program were the concrete compressive strength, the lap splice length, the amount of transverse reinforcement provided within the splice region, and the shape of the transverse reinforcement around the spliced bars. The experimental results showed that the displacement ductility increased and the mode of failure changed from a splitting bond failure to a flexural failure when the amount of the transverse reinforcement in the splice region increased, and the compressive strength increased up to 100 MPa. The presence of the transverse reinforcement around the spliced bars had a pronounced effect on increasing the ultimate load, the ultimate deflection, and the displacement ductility. The prediction of maximum steel stresses for spliced bars using the ACI 318-05 building code was compared with the experimental results. The comparison showed that the effect of the transverse reinforcement around spliced bars has to be considered into the design equations for lap splice length in high-strength concrete beams.

  9. Optimum design of bolted composite lap joints under mechanical and thermal loading

    NASA Astrophysics Data System (ADS)

    Kradinov, Vladimir Yurievich

    A new approach is developed for the analysis and design of mechanically fastened composite lap joints under mechanical and thermal loading. Based on the combined complex potential and variational formulation, the solution method satisfies the equilibrium equations exactly while the boundary conditions are satisfied by minimizing the total potential. This approach is capable of modeling finite laminate planform dimensions, uniform and variable laminate thickness, laminate lay-up, interaction among bolts, bolt torque, bolt flexibility, bolt size, bolt-hole clearance and interference, insert dimensions and insert material properties. Comparing to the finite element analysis, the robustness of the method does not decrease when modeling the interaction of many bolts; also, the method is more suitable for parametric study and design optimization. The Genetic Algorithm (GA), a powerful optimization technique for multiple extrema functions in multiple dimensions search spaces, is applied in conjunction with the complex potential and variational formulation to achieve optimum designs of bolted composite lap joints. The objective of the optimization is to acquire such a design that ensures the highest strength of the joint. The fitness function for the GA optimization is based on the average stress failure criterion predicting net-section, shear-out, and bearing failure modes in bolted lap joints. The criterion accounts for the stress distribution in the thickness direction at the bolt location by applying an approach utilizing a beam on an elastic foundation formulation.

  10. Large-scale Advanced Prop-fan (LAP) static rotor test report

    NASA Technical Reports Server (NTRS)

    Degeorge, Charles L.; Turnberg, Jay E.; Wainauski, Harry S.

    1987-01-01

    Discussed is Static Rotor Testing of the SR-7L Large Scale Advanced Prop-Fan (LAP). The LAP is an advanced 9 foot diameter, 8 bladed propeller designed and built by Hamilton Standard under contract to the NASA Lewis Research Center. The Prop-Fan employs thin swept blades to provide efficient propulsion at flight speeds up to Mach .85. Static Testing was conducted on a 10,000 HP whirl rig at Wright Patterson Air Force Base. The test objectives were to investigate the Prop-Fan static aerodynamic and structural dynamic performance, determine the blade steady state stressers and deflections and to measure steady and unsteady pressures on the SR-7L blade surface. The measured performance of the LAP correlated well with analytical predictions at blade pitch angles below 30 deg. A stall buffet phenomenon was observed at blade pitch angles above 30 deg. This phenomenon manifested itself by elevated blade vibratory stress levels and lower than expected thrust produced and power absorbed by the Prop-Fan for a given speed and blade angle.

  11. Enhancing pulsed eddy current for inspection of P-3 Orion lap-joint structures

    NASA Astrophysics Data System (ADS)

    Butt, D. M.; Underhill, P. R.; Krause, T. W.

    2016-02-01

    During flight, aircraft are subjected to cyclic loading. In the Lockheed P-3 Orion airframe, this cyclic loading can lead to development of fatigue cracks at steel fastener locations in the top and second layers of aluminum wing skin lap-joints. An inspection method that is capable of detecting these cracks, without fastener removal, is desirable as this can minimize aircraft downtime, while subsequently reducing the risk of collateral damage. The ability to detect second layer cracks has been demonstrated using a Pulsed Eddy Current (PEC) probe design that utilizes the ferrous fastener as a flux conduit. This allows for deeper penetration of flux into the lap-joint second layer and consequently, sensitivity to the presence of cracks. Differential pick-up coil pairs are used to sense the eddy current response due to the presence of a crack. The differential signal obtained from pick-up coils on opposing sides of the fastener is analyzed using a Modified Principal Components Analysis (MPCA). This is followed by a cluster analysis of the resulting MPCA scores to separate fastener locations with cracks from those without. Probe design features, data acquisition system parameters and signal post-processing can each have a strong impact on crack detection. Physical probe configurations and signal analysis processes, used to enhance the PEC system for detection of cracks in P-3 Orion lap-joint structures, are investigated and an enhanced probe design is identified.

  12. Probabilistic seismic performance assessment of lap-spliced RC columns retrofitted by steel wrapping jackets

    NASA Astrophysics Data System (ADS)

    Choi, Eunsoo; Youn, Heejung; Cho, Baik-Soon

    2016-06-01

    In this study, the seismic fragility curves of two reinforced concrete (RC) columns that were lap-spliced at the bottom and retrofitted with steel wrapping jackets were generated. Their seismic performance was probabilistically assessed in comparison to that of lap-spliced or continuous reinforcement RC columns. This study used two types of steel wrapping jackets, a full jacket and a split jacket. Analytical models of the four types of columns were developed based on the experimental results of the columns using OpenSEES, which is effective in conducting nonlinear time history analyses. A suite of ten artificial ground motions, modified from recorded ground motions, was used to perform nonlinear time history analyses of the analytical models with scaling of the peak ground acceleration from 0.1 g to 1.0 g in increments of 0.1 g. The steel wrapping jackets did not increase the medians for yield (slight damage state) of the lap-spiced column and did not exceed the corresponding median of the continuous reinforcement column. However, the two steel jackets increased the medians for failure by 1.872 and 2.017 times, respectively, and exceeded the corresponding median of the continuous reinforcement column by 11.8% and 20.5%, respectively.

  13. Aggression Can be Contagious: Longitudinal Associations between Proactive Aggression and Reactive Aggression Among Young Twins

    PubMed Central

    Dickson, Daniel J.; Richmond, Ashley; Brendgen, Mara; Vitaro, Frank; Laursen, Brett; Dionne, Ginette; Boivin, Michel

    2015-01-01

    The present study examined sibling influence over reactive and proactive aggression in a sample of 452 same-sex twins (113 male dyads, 113 female dyads). Between and within siblings influence processes were examined as a function of relative levels of parental coercion and hostility to test the hypothesis that aggression contagion between twins occurs only among dyads who experience parental coerciveness. Teacher reports of reactive and proactive aggression were collected for each twin in kindergarten (M = 6.04 years; SD = 0.27) and in first grade (M = 7.08 years; SD = 0.27). Families were divided into relatively low, average, and relatively high parental coercion-hostility groups on the basis of maternal reports collected when the children were 5 years old. In families with relatively high levels of parental coercion-hostility, there was evidence of between-sibling influence, such that one twin’s reactive aggression at age 6 predicted increases in the other twin’s reactive aggression from ages 6 to 7, and one twin’s proactive aggression at age 6 predicted increases in the other twin’s proactive aggression from ages 6 to 7. There was also evidence of within-sibling influence such that a child’s level of reactive aggression at age 6 predicted increases in the same child’s proactive aggression at age 7, regardless of parental coercion-hostility. The findings provide new information about the etiology of reactive and proactive aggression and individual differences in their developmental interplay. PMID:25683448

  14. An Aggressive Retroperitoneal Fibromatosis

    PubMed Central

    Campara, Zoran; Spasic, Aleksandar; Aleksic, Predrag; Milev, Bosko

    2016-01-01

    Introduction: Aggressive fibromatosis (AF) is a heterogeneous group of mesenchymal tumors that have locally infiltrative growth and a tendency to relapse. The clinical picture is often conditioned by the obstruction of the ureter or small intestine. Diagnosis is based on clinical, radiological and histological parameters. A case report: We report a case of male patient, aged 35 years, with the retroperitoneal fibromatosis. He reported to the physician because of frequent urination with the feeling of pressure and pain. Computed tomography revealed the tumor mass on the front wall of the bladder with diameter of 70mm with signs of infiltration of the musculature of the anterior abdominal wall. Endoscopic transurethral biopsy showed proliferative lesion binders by type of fibromatosis. The tumor was surgically removed in a classical way. The patient feels well and has no recurrence thirty-six months after the operative procedure. Conclusion: The complete tumor resection is the therapeutic choice for the primary tumor as well as for a relapse. PMID:27147794

  15. From aggressiveness to creativity.

    PubMed

    Mrevlje, Gorazd V

    2004-02-01

    Psychology has a long tradition of considering human creativity as a distinct human characteristic and a special kind of human activity. After explaining the key motives for such an attitude, the author discusses those forms of healthy aggressiveness that stand out as necessary and constitutive elements of the creative process. Taking the well-known statement of C. G. Jung's 'The person who does not build (create), will demolish and destroy' as a starting point, the author compares the basic premises for understanding the process of human creativity, at the same time drawing on Freud's psychology of the individual and Jung's principle of the collective unconscious as well as his notion of 'complexes'. In doing so, the author somewhat boldly paraphrases Jung's dictum: 'In order to be creative, rather than just constructive, one must occasionally also destroy'. With reference to Wallas, Taylor and Neumann (Wallas 1926; Taylor 1959;;Neumann 2001), the author goes on to explore those concepts which help us to investigate the phenomenon of human creativity, drawing distinctions between emergent, expressive, productive, inventive and innovative creativity. The second part of the article discusses the importance of intelligence, originality, nonconformity, subversiveness and free-mindedness for the creative process of human beings. The author concludes with a further explanation of Erich Neumann's argument that human creativity cannot be understood solely as a result of sociogenetic factors, and argues that it is only by taking into consideration Jung's perception of creativity that a global ontological understanding of these processes can be achieved.

  16. More aggressive cartoons are funnier.

    PubMed

    McCauley, C; Woods, K; Coolidge, C; Kulick, W

    1983-04-01

    Independent rankings of humor and aggressiveness were obtained for sets of cartoons drawn randomly from two different magazines. The correlation of median humor and median aggressiveness rankings ranged from .49 to .90 in six studies involving six different sets of cartoons and six different groups of subjects, including children and adults, high and low socioeconomic status (SES) individuals, and native- and foreign-born individuals. This correlation is consistent with Freudian, arousal, and superiority theories of humor. Another prediction of Freudian theory, that high-SES subjects should be more appreciative of aggressive humor than low-SES subjects, was not supported.

  17. Predicting workplace aggression and violence.

    PubMed

    Barling, Julian; Dupré, Kathryne E; Kelloway, E Kevin

    2009-01-01

    Consistent with the relative recency of research on workplace aggression and the considerable media attention given to high-profile incidents, numerous myths about the nature of workplace aggression have emerged. In this review, we examine these myths from an evidence-based perspective, bringing greater clarity to our understanding of the predictors of workplace aggression. We conclude by pointing to the need for more research focusing on construct validity and prevention issues as well as for methodologies that minimize the likelihood of mono-method bias and that strengthen the ability to make causal inferences.

  18. Uncovering the molecular networks in periodontitis

    PubMed Central

    Trindade, Fábio; Oppenheim, Frank G.; Helmerhorst, Eva J.; Amado, Francisco; Gomes, Pedro S.; Vitorino, Rui

    2015-01-01

    Periodontitis is a complex immune-inflammatory disease that results from a preestablished infection in gingiva, mainly due to Gram-negative bacteria that colonize deeper in gingival sulcus and latter periodontal pocket. Host inflammatory and immune responses have both protective and destructive roles. Although cytokines, prostaglandins, and proteases struggle against microbial burden, these molecules promote connective tissue loss and alveolar bone resorption, leading to several histopathological changes, namely destruction of periodontal ligament, deepening of periodontal pocket, and bone loss, which can converge to attain tooth loss. Despite the efforts of genomics, transcriptomics, proteomics/peptidomics, and metabolomics, there is no available biomarker for periodontitis diagnosis, prognosis, and treatment evaluation, which could assist on the established clinical evaluation. Nevertheless, some genes, transcripts, proteins and metabolites have already shown a different expression in healthy subjects and in patients. Though, so far, ‘omics approaches only disclosed the host inflammatory response as a consequence of microbial invasion in periodontitis and the diagnosis in periodontitis still relies on clinical parameters, thus a molecular tool for assessing periodontitis lacks in current dental medicine paradigm. Saliva and gingival crevicular fluid have been attracting researchers due to their diagnostic potential, ease, and noninvasive nature of collection. Each one of these fluids has some advantages and disadvantages that are discussed in this review. PMID:24828325

  19. Quorum sensing inhibition, relevance to periodontics.

    PubMed

    Yada, Sudheer; Kamalesh, B; Sonwane, Siddharth; Guptha, Indra; Swetha, R K

    2015-01-01

    Quorum sensing helps bacteria to communicate with each other and in coordinating their behavior. Many diseases of human beings, plants, and animals are mediated by quorum sensing. Various approaches are being tried to inhibit this communication to control the diseases caused by bacteria. Periodontal pathogens also communicate through quorum sensing and new approaches to treat periodontal disease using quorum sensing inhibition need to explored.

  20. [Diabetes and periodontitis: A bidirectional relationship].

    PubMed

    Bascones-Martínez, Antonio; Muñoz-Corcuera, Marta; Bascones-Ilundain, Jaime

    2015-07-06

    Diabetes mellitus is a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, a defect in insulin action or a combination of both. Periodontitis is now considered a chronic localized infection of the oral cavity that can trigger inflammatory host immune responses at local and systemic levels, and can also be a source of bacteremia. It is now known that periodontitis has an influence on the pathogenesis of certain systemic diseases. The biological relationship between diabetes and periodontal disease is well documented. In the mid-90s sufficient scientific support for the association between diabetes and periodontitis was published, and periodontitis was designated as the sixth complication of diabetes. There have been studies that show an improvement in both clinical and immunological parameters of periodontitis and glycemic control in long-term diabetes after treatment of periodontal disease. In addition, scientific evidence confirms that poorer glycemic control contributes to a worse periodontal condition. The interplay between the 2 conditions highlights the importance of the need for a good communication between the internist and dentist about diabetic patients, considering always the possibility that the 2 diseases may be occurring simultaneously in order to ensure an early diagnosis of both.

  1. Relation between periodontitis and helicobacter pylori infection

    PubMed Central

    Zheng, Pei; Zhou, Weiying

    2015-01-01

    Objective: The correlation between periodontitis and Helicobacter pylori (H. pylori) infection in the mouth was analyzed. Method: 70 elderly patients with periodontitis treated at our hospital from January 2013 to December 2014 were recruited. Dental plaques and gargle were collected for H. pylori detection using PCR technique. Periodontal health status of the patients was recorded. 70 control cases with healthy periodontium were also included. The symptoms of H. pylori infection in the mouth were compared between the two groups, and the results were analyzed statistically. Results: The positive rate of urease C gene of H. pylori in the periodontitis group was 71.4%; the positive rate of cagA gene was 35.7%. The positive rate of urease C gene of H. pylori in the control group was 34.3% and that of cagA gene was 12.9%. The two groups did not show significant differences in these two indicators (P<0.05). The positive detection rate of urease C gene of H. pylori in subgingival plaques was higher than that in supragingival plaques, and the difference was of statistical significance (P<0.05). The positive detection rate of H. pylori in patients with moderate and severe periodontitis was obviously higher than that of patients with mild periodontitis (P<0.05). Conclusion: Periodontal health status of elderly people with periodontitis correlated with H. pylori infection in the stomach. PMID:26629215

  2. An update on periodontic-orthodontic interrelationships

    PubMed Central

    Dannan, Aous

    2010-01-01

    Talking about periodontic-orthodontic interrelationships is related primarily to the 1960s, where a generalized increase in salivary bacterial counts, especially Lactobacillus, had been shown after orthodontic band placement. The purpose of this article is to provide the dental practitioner with basic understanding of the interrelationship between periodontics and orthodontics by means of representing classical studies, and, to give an update on this topic by demonstrating the most recent opinions concerning periodontic-orthodontic interrelationships. Specific areas reviewed are the ability of orthodontic treatment to afford some degree of protection against periodontal breakdown, short-term and long-term effects of orthodontic treatment on the periodontium, and some mucogingival considerations. Topics considering orthodontic treatment in periodontally compromised patients were not included in this review. While past studies have shown that orthodontic treatment can positively affect the periodontal health, recent reviews indicate an absence of reliable evidence for the positive effects of orthodontic therapy on patients’ periodontal status. Periodontic-orthodontic interrelationships are still controversial issues. However, a standard language between the periodontist and the orthodontist must always be established to eliminate the existing communications barrier, and to improve the outcomes of the whole treatment. PMID:20922083

  3. Characteristics of cellular composition of periodontal pockets

    PubMed Central

    Hasiuk, Petro; Hasiuk, Nataliya; Kindiy, Dmytro; Ivanchyshyn, Victoriya; Kalashnikov, Dmytro; Zubchenko, Sergiy

    2016-01-01

    Purpose The development of inflammatory periodontal disease in young people is an urgent problem of today's periodontology, and requires a development of new methods that would give an opportunity not only to diagnose but also for prognosis of periodontitis course in a given patients contingent. Results Cellular structure of periodontal pockets is presented by hematogenous and epithelial cells. Our results are confirmed by previous studies, and show that the penetration of periodontal pathogens leads to formation in periodontal tissue of a highly active complex compounds—cytokines that are able to modify the activity of neutrophils and reduce their specific antibacterial properties. Cytokines not only adversely affect the periodontal tissues, but also cause further activation of cells that synthesized them, and inhibit tissue repair and process of resynthesis of connective tissue by fibroblasts. Conclusion Neutrophilic granulocytes present in each of the types of smear types, but their functional status and quantitative composition is different. The results of our cytological study confirmed the results of immunohistochemical studies, and show that in generalized periodontitis, an inflammatory cellular elements with disorganized epithelial cells and connective tissue of the gums and periodontium, and bacteria form specific types of infiltration in periodontal tissues. PMID:28180007

  4. [Pathophysiology of aggressive behavior: evaluation and management of pathological aggression].

    PubMed

    Pompili, E; Carlone, C; Silvestrini, C; Nicolò, G

    2016-01-01

    This work aims to define the aggression in all its forms, with notes on management and rapid tranquilization. The pathological aggression is described as a non-homogeneous phenomenon, it is variable in according to social, psychological and biological agents. The distinction of violence between affective aggression and predatory aggression can be functional to the prediction of outcome of any treatment. In general, a pattern of predatory violence tend to match with patients unresponsive and not compliant to treatment, a low probability to predict future violence and, therefore, a difficulty in managing risk. The affective aggressor, however, shows increased probability of treatment response, with more predictability of violent actions in reaction to situations perceived as threatening and, therefore, greater management of future violence risk. Those who act affective violence tend to show a wide range of emotional and cognitive problems, while those who act with predatory patterns show greater inclination to aggression and antisocial behavior. Aggression that occurs in psychiatry mostly appears to be affective, therefore susceptible to modulation through treatments.

  5. Parameter on comprehensive periodontal examination. American Academy of Periodontology.

    PubMed

    2000-05-01

    The American Academy of Periodontology has developed the following parameter on comprehensive periodontal examination for periodontal diseases. Appropriate screening procedures may be performed to determine the need for a comprehensive periodontal evaluation. Periodontal Screening and Recording (PSR), a screening procedure endorsed by the American Dental Association and the American Academy of Periodontology, may be utilized.

  6. Estimation of interleukin-18 in the gingival crevicular fluid and serum of Bengali population with periodontal health and disease

    PubMed Central

    Nair, Vineet; Bandyopadhyay, Prasanta; Kundu, Debabrata; Das, Satadal

    2016-01-01

    Context: Host's immune response elicits cytokines in response to bacterial challenge. We explore role of one such cytokine interleukin-18 (IL-18) in periodontal health and disease. Aims: IL-18 is a pro-inflammatory and tumor suppressive cytokine. Dental literatures suggest that IL-18 might have a role to play in the progression from oral health to periodontal disease. Therefore, this study was undertaken to elucidate the level and role of IL-18 in the gingival crevicular fluid (GCF) and serum of individuals with healthy gingiva, chronic gingivitis, chronic periodontitis, and aggressive periodontitis before and after periodontal therapy. Settings and Design: Eighty individuals chosen for the study were divided into healthy control group (1A), chronic gingivitis (2A), chronic periodontitis (3A), and aggressive periodontitis (4A) with twenty individuals each. Criteria for the division were the subject's gingival index, probing pocket depth, clinical attachment loss, and radiographic evidence of bone loss. Materials and Methods: The individuals underwent treatment (scaling in case of Groups 1A and 2A and scaling and root planing followed by flap surgery in Groups 3A and 4A) to form posttreatment Groups 1B, 2B, 3B, and 4B, respectively. Thus, a total of 160 GCF and 160 serum samples were collected and tested by ELISA. Statistical Analysis Used: Intergroup comparison was done by post hoc Tukey's test. Results: The mean IL-18 concentration was greatest in Group 3A (GCF 144.61 pg/μl, serum 55.12 pg/ml) followed by Group 4A (GCF 98.55 pg/μl, serum 39.06 pg/ml), Group 2A (GCF 22.27 pg/μl, serum 27.73 pg/ml) and lowest (GCF 17.94 pg/μl, serum 11.49 pg/ml) in Group 1A. Posttreatment groups (1B–4B) showed reduction in the mean IL-18 concentration in both GCF and serum. Conclusions: As the inflammation increased, there was a concomitant increase in the level of IL-18 and vice versa following periodontal therapy. PMID:27563198

  7. The pro-apoptotic and pro-inflammatory effects of calprotectin on human periodontal ligament cells.

    PubMed

    Zheng, Yunfei; Hou, Jianxia; Peng, Lei; Zhang, Xin; Jia, Lingfei; Wang, Xian'e; Wei, Shicheng; Meng, Huanxin

    2014-01-01

    Calprotectin, a heterodimer of S100A8 and S100A9 subunits, is associated with inflammatory disorders such as rheumatoid arthritis and cystic fibrosis. Although calprotectin levels are increased significantly in the gingival crevicular fluid (GCF) of periodontitis patients, its effects on periodontal ligament cells (PDLCs) remain largely unknown. The aim of this study was to evaluate calprotectin levels in the GCF of generalized aggressive periodontitis (AgP) patients and to investigate the effects of recombinant human calprotectin (rhS100A8/A9) and its subunits (rhS100A8 and rhS100A9) in PDLCs. Both the concentration and amount of crevicular calprotectin were significantly higher in the AgP group compared with healthy controls. In addition, the GCF calprotectin levels were correlated positively with clinical periodontal parameters including bleeding index, probing depth, and clinical attachment loss. rhS100A8/A9 promoted cell apoptosis, whereas rhS100A8 and rhS100A9 individually exerted little effect on apoptosis in PDLCs. rhS100A9 and rhS100A8/A9 increased the activation of nuclear factor-κB (NF-κB) by promoting the nuclear translocation of p65 in PDLCs, subsequently inducing expression of the pro-inflammatory cytokines IL-6, IL-8, TNFα, and COX2. Treatment with an NF-κB inhibitor partially reversed the rhS100A9- and rhS100A8/A9-induced upregulation of the pro-inflammatory cytokines. rhS100A9, and not rhS100A8, was mainly responsible for the pro-inflammatory role of calprotectin. Collectively, our results suggest that calprotectin promotes apoptosis and the inflammatory response in PDLCs via rhS100A9. These findings might help identify novel treatments for periodontitis.

  8. Acceleration of purine degradation by periodontal diseases.

    PubMed

    Barnes, V M; Teles, R; Trivedi, H M; Devizio, W; Xu, T; Mitchell, M W; Milburn, M V; Guo, L

    2009-09-01

    Periodontal diseases, such as gingivitis and periodontitis, are characterized by bacterial plaque accumulation around the gingival crevice and the subsequent inflammation and destruction of host tissues. To test the hypothesis that cellular metabolism is altered as a result of host-bacteria interaction, we performed an unbiased metabolomic profiling of gingival crevicular fluid (GCF) collected from healthy, gingivitis, and periodontitis sites in humans, by liquid and gas chromatography mass spectrometry. The purine degradation pathway, a major biochemical source for reactive oxygen species (ROS) production, was significantly accelerated at the disease sites. This suggests that periodontal-disease-induced oxidative stress and inflammation are mediated through this pathway. The complex host-bacterial interaction was further highlighted by depletion of anti-oxidants, degradation of host cellular components, and accumulation of bacterial products in GCF. These findings provide new mechanistic insights and a panel of comprehensive biomarkers for periodontal disease progression.

  9. Stem cells, tissue engineering and periodontal regeneration.

    PubMed

    Han, J; Menicanin, D; Gronthos, S; Bartold, P M

    2014-06-01

    The aim of this review is to discuss the clinical utility of stem cells in periodontal regeneration by reviewing relevant literature that assesses the periodontal-regenerative potential of stem cells. We consider and describe the main stem cell populations that have been utilized with regard to periodontal regeneration, including bone marrow-derived mesenchymal stem cells and the main dental-derived mesenchymal stem cell populations: periodontal ligament stem cells, dental pulp stem cells, stem cells from human exfoliated deciduous teeth, stem cells from apical papilla and dental follicle precursor cells. Research into the use of stem cells for tissue regeneration has the potential to significantly influence periodontal treatment strategies in the future.

  10. Matrix Metalloproteinases as Regulators of Periodontal Inflammation.

    PubMed

    Franco, Cavalla; Patricia, Hernández-Ríos; Timo, Sorsa; Claudia, Biguetti; Marcela, Hernández

    2017-02-17

    Periodontitis are infectious diseases characterized by immune-mediated destruction of periodontal supporting tissues and tooth loss. Matrix metalloproteinases (MMPs) are key proteases involved in destructive periodontal diseases. The study and interest in MMP has been fuelled by emerging evidence demonstrating the broad spectrum of molecules that can be cleaved by them and the myriad of biological processes that they can potentially regulate. The huge complexity of MMP functions within the 'protease web' is crucial for many physiologic and pathologic processes, including immunity, inflammation, bone resorption, and wound healing. Evidence points out that MMPs assemble in activation cascades and besides their classical extracellular matrix substrates, they cleave several signalling molecules-such as cytokines, chemokines, and growth factors, among others-regulating their biological functions and/or bioavailability during periodontal diseases. In this review, we provide an overview of emerging evidence of MMPs as regulators of periodontal inflammation.

  11. Matrix Metalloproteinases as Regulators of Periodontal Inflammation

    PubMed Central

    Franco, Cavalla; Patricia, Hernández-Ríos; Timo, Sorsa; Claudia, Biguetti; Marcela, Hernández

    2017-01-01

    Periodontitis are infectious diseases characterized by immune-mediated destruction of periodontal supporting tissues and tooth loss. Matrix metalloproteinases (MMPs) are key proteases involved in destructive periodontal diseases. The study and interest in MMP has been fuelled by emerging evidence demonstrating the broad spectrum of molecules that can be cleaved by them and the myriad of biological processes that they can potentially regulate. The huge complexity of MMP functions within the ‘protease web’ is crucial for many physiologic and pathologic processes, including immunity, inflammation, bone resorption, and wound healing. Evidence points out that MMPs assemble in activation cascades and besides their classical extracellular matrix substrates, they cleave several signalling molecules—such as cytokines, chemokines, and growth factors, among others—regulating their biological functions and/or bioavailability during periodontal diseases. In this review, we provide an overview of emerging evidence of MMPs as regulators of periodontal inflammation. PMID:28218665

  12. Laser Supported Reduction of Specific Microorganisms in the Periodontal Pocket with the Aid of an Er,Cr:YSGG Laser: A Pilot Study

    PubMed Central

    Gutknecht, N.; Van Betteray, C.; Ozturan, S.; Vanweersch, L.; Franzen, R.

    2015-01-01

    Objective. The aim of this study was to evaluate the effectiveness of a radial firing tip of an Er,Cr:YSGG laser as an adjunct to a nonsurgical periodontal treatment. Methods. Twelve patients with chronic or aggressive periodontitis were treated by conventional periodontal treatment using ultrasonic devices and hand instruments and, additionally, in two quadrants with an Er,Cr:YSGG laser. A new radial firing tip (RFPT 14-5, Biolase) was used with 1.5 W, 30 Hz, 11% air, 20% water, and pulse duration 140 μs. Microbiological smears were taken before treatment, one day after lasing, and three and six months after lasing. Pocket depths of all periodontal sites were measured before and six months after treatment. Results. The total bacterial load of Prevotella intermedia, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans inside the pocket was reduced significantly throughout the whole examination time. Greater pocket depth reductions were observed in all groups. There was a slight higher reduction of pocket depth in the lased group after six months. Conclusions. These results support the thesis that Er,Cr:YSGG laser supported periodontal treatment leads to a significant reduction of periopathogenes and thereby helps the maintenance of periodontal health. PMID:25879057

  13. Quantifying Aggressive Behavior in Zebrafish.

    PubMed

    Teles, Magda C; Oliveira, Rui F

    2016-01-01

    Aggression is a complex behavior that influences social relationships and can be seen as adaptive or maladaptive depending on the context and intensity of expression. A model organism suitable for genetic dissection of the underlying neural mechanisms of aggressive behavior is still needed. Zebrafish has already proven to be a powerful vertebrate model organism for the study of normal and pathological brain function. Despite the fact that zebrafish is a gregarious species that forms shoals, when allowed to interact in pairs, both males and females express aggressive behavior and establish dominance hierarchies. Here, we describe two protocols that can be used to quantify aggressive behavior in zebrafish, using two different paradigms: (1) staged fights between real opponents and (2) mirror-elicited fights. We also discuss the methodology for the behavior analysis, the expected results for both paradigms, and the advantages and disadvantages of each paradigm in face of the specific goals of the study.

  14. Vasopressin/oxytocin and aggression.

    PubMed

    Ferris, Craig F

    2005-01-01

    Vasopressin/oxytocin and related peptides comprise a phylogenetically old superfamily of chemical signals in both vertebrates and invertebrates. Each peptide isoform has its own distinct receptor subtype and specific cellular action. The conservation and dispersion of vasopressin/oxytocin signalling systems across the animal kingdom attests to their functional significance in evolution. Indeed, they are involved in the physiology of fluid balance, carbohydrate metabolism, thermoregulation, immunity and reproduction. In addition, these peptides evolved a role in social behaviours related to aggression and affiliation. The focus of this chapter is the role of vasopressin/oxytocin as chemical signals in the brain altering aggressive responding in a context- and species-dependent manner. There is compelling evidence from several mammalian species including humans that vasopressin enhances aggression. The activity of the vasopressin appears linked to the serotonin system providing a mechanism for enhancing and suppressing aggressive behaviour.

  15. Environmental factors and aggressive behavior

    SciTech Connect

    Anderson, A.C.

    1982-07-01

    This paper briefly reviews some of the research areas which indicate a correlation between environmental factors and initiation of aggressive behavior. Environmental factors including lunar influences, month of birth, climate and the effects of crowding and certain chemicals are discussed.

  16. Role of Maternal Periodontitis in Preterm Birth

    PubMed Central

    Ren, Hongyu; Du, Minquan

    2017-01-01

    In the last two decades, many studies have focused on whether periodontitis is a risk factor for preterm birth (PTB). However, both epidemiological investigation and intervention trials have reached contradictory results from different studies. What explains the different findings, and how should future studies be conducted to better assess this risk factor? This article reviews recent epidemiological, animal, and in vitro studies as well as intervention trials that evaluate the link between periodontitis and PTB. Periodontitis may act as a distant reservoir of microbes and inflammatory mediators and contribute to the induction of PTB. Animal studies revealed that maternal infections with periodontal pathogens increase levels of circulating IL-1β, IL-6, IL-8, IL-17, and TNF-α and induce PTB. In vitro models showed that periodontal pathogens/byproducts induce COX-2, IL-8, IFN-γ, and TNF-α secretion and/or apoptosis in placental tissues/cells. The effectiveness of periodontal treatment to prevent PTB is influenced by the diagnostic criteria of periodontitis, microbial community composition, severity of periodontitis, treatment strategy, treatment efficiency, and the period of treatment during pregnancy. Although intervention trials reported contradictory results, oral health maintenance is an important part of preventive care that is both effective and safe throughout pregnancy and should be supported before and during pregnancy. As contradictory epidemiological and intervention studies continue to be published, two new ideas are proposed here: (1) severe and/or generalized periodontitis promotes PTB and (2) periodontitis only promotes PTB for pregnant women who are young or HIV-infected or have preeclampsia, pre-pregnancy obesity, or susceptible genotypes. PMID:28243243

  17. [Biology of aggression in dogs].

    PubMed

    Feddersen-Petersen, D U

    2001-03-01

    The science of ethology is concerned with the way external stimuli and internal events cause animals to fight in a particular way. The classification of dog breeds with respect to their relative danger to humans makes no sense, as both, the complex antecedent conditions in which aggressive behaviour occurs, and its ramifying consequences in the individual dog's ecological and social environment, are not considered. From a biological point of view, environmental and learning effects are always superimposed upon genetic influences. Based on the recent developments in the study of ethology, aggression of wolves (Canis lupus L.) and domesticated dogs (Canis lupus f. familiaris) was put into context with respect to other aspects of the lifestyle of wild and domestic canids. Aggressive behaviour does not occur in a biological vacuum. This is also true for domestic dogs and their relationship to human partners. Individual dogs can become highly aggressive and dangerous. Their development and social situation will be presented and discussed in case studies. Finally, there is the question about defining "normal aggression" versus symptoms for maladaptive aggression resp. danger to humans as conspecifics. It is possible to protect the safety of the public and at the the same time practise animal care. Effective animal control legislation must focus on responsible ownership and socialisation of pups f.e. Problems are not unique to some breeds.

  18. Music, Substance Use, and Aggression

    PubMed Central

    Chen, Meng-Jinn; Miller, Brenda A.; Grube, Joel W.; Waiters, Elizabeth D.

    2016-01-01

    Objective This study investigated whether young people’s substance use and aggressive behaviors are related to their listening to music containing messages of substance use and violence. Method Data were collected using self-administered questionnaires and from a sample of community college students aged 15-25 (N = 1056; 43% male). A structural equation modeling method was used to simultaneously assess the associations between listening to various genres of music, alcohol use, illicit drug use, and aggressive behaviors, taking into account respondents’ age, gender, race/ethnicity, and level of sensation seeking. Results Listening to rap music was significantly and positively associated with alcohol use, problematic alcohol use, illicit drug use, and aggressive behaviors when all other variables were controlled. Additionally, alcohol and illicit drug use were positively associated with listening to musical genres of techno and reggae. Control variables such as sensation seeking, age, gender and race/ethnicity were significantly related to substance use and aggressive behaviors. Conclusion The findings suggest that young people’s substance use and aggressive behaviors may be related to their frequent exposure to music containing references to substance use and violence. Conversely, music listening preference may reflect some personal predispositions or lifestyle preferences. Alternatively, substance use, aggression and music preference are independent constructs, but share common “third factors.” PMID:16608146

  19. Driver irritation and aggressive behaviour.

    PubMed

    Björklund, Gunilla M

    2008-05-01

    A sample of 98 drivers responded to a Swedish version of the UK Driving Anger Scale [UK DAS; [Lajunen, T., Parker, D., Stradling, S.G., 1998. Dimensions of driver anger, aggressive and highway code violations and their mediation by safety orientation in UK drivers. Transport. Res. Part F 1, 107-121]. The results indicated that the Swedish version, like the British original, measures three sources of driver irritation: "progress impeded", "reckless driving", and "direct hostility". Structural equation modelling was used to investigate the relationships between the three sources of self-reported driver irritation, aggressive actions, speed, sex, age, and annual mileage. The models suggested a positive relationship between the amount of driver irritation and frequency of aggressive actions for all three sources of irritation. Female drivers tended to become more irritated than male drivers, while the male drivers tended to act aggressively more often. Surprisingly, drivers who reported that they enjoy fast speeds did not become more irritated than slower drivers when obstructed. The important conclusions are that experienced irritation often leads to openly aggressively actions, and that expression of aggressive behaviours may be a cause of other drivers' feeling of irritation.

  20. Normative beliefs about aggression and cyber aggression among young adults: a longitudinal investigation.

    PubMed

    Wright, Michelle F; Li, Yan

    2013-01-01

    This longitudinal study examined normative beliefs about aggression (e.g., face-to-face, cyber) in relation to the engagement in cyber aggression 6 months later among 126 (69 women) young adults. Participants completed electronically administered measures assessing their normative beliefs, face-to-face and cyber aggression at Time 1, and cyber aggression 6 months later (Time 2). We found that men reported more cyber relational and verbal aggression when compared to women. After controlling for each other, Time 1 face-to-face relational aggression was positively related to Time 2 cyber relational aggression, whereas Time 1 face-to-face verbal aggression was positively related to Time 2 cyber verbal aggression. Normative beliefs regarding cyber aggression was positively related to both forms of cyber aggression 6 months later, after controlling for normative beliefs about face-to-face aggression. Furthermore, a significant two-way interaction between Time 1 cyber relational aggression and normative beliefs about cyber relational aggression was found. Follow-up analysis showed that Time 1 cyber relational aggression was more strongly related to Time 2 cyber relational aggression when young adults held higher normative beliefs about cyber relational aggression. A similar two-way interaction was found for cyber verbal aggression such that the association between Time 1 and Time 2 cyber verbal aggression was stronger at higher levels of normative beliefs about cyber verbal aggression. Results are discussed in terms of the social cognitive and behavioral mechanisms associated with the engagement of cyber aggression.

  1. RANKL expression in periodontal disease: where does RANKL come from?

    PubMed

    Chen, Bin; Wu, Wenlei; Sun, Weibin; Zhang, Qian; Yan, Fuhua; Xiao, Yin

    2014-01-01

    Periodontitis is an inflammatory disease characterized by periodontal pocket formation and alveolar bone resorption. Periodontal bone resorption is induced by osteoclasts and receptor activator of nuclear factor-κB ligand (RANKL) which is an essential and central regulator of osteoclast development and osteoclast function. Therefore, RANKL plays a critical role in periodontal bone resorption. In this review, we have summarized the sources of RANKL in periodontal disease and explored which factors may regulate RANKL expression in this disease.

  2. [Periodontitis and systemic diseases: from science to clinical practice].

    PubMed

    Thomas, R Z; Loos, B G; Teeuw, W; Kunnen, A; van Winkelhoff, A J; Abbas, F

    2015-10-01

    The evidence for an association between systemic diseases and periodontitis is strongest with diabetes mellitus type 2 and cardiovascular disease. There is a moderate association of periodontitis with adverse pregnancy outcomes and rheumatoid arthritis. Periodontal treatment has, on average, a positive effect on reducing systemic infection and improving the condition of the vascular system. For diabetes patients, periodontal treatment can also have a positive effect on metabolic regulation. There is insufficient evidence that periodontal treatment prevents adverse pregnancy outcomes and rheumatoid arthritis.

  3. The Structure and Enzyme Characteristics of a Recombinant Leucine Aminopeptidase rLap1 from Aspergillus sojae and Its Application in Debittering.

    PubMed

    Huang, Wei-Qian; Zhong, Li-Fen; Meng, Zhi-Zhong; You, Zi-Juan; Li, Jia-Zhou; Luo, Xiao-Chun

    2015-09-01

    A leucine aminopeptidase Lap1 was cloned from Aspergillus sojae GIM3.30. The truncated Lap1 without a signal peptide was over-expressed in P. pastoris, and the enzymatic characteristics of recombinant Lap1 (rLap1) were tested. The rLap1 was about 36.7 kDa with an optimal pH 8.0 and optimal temperature 50 °C for substrate Leu-p-nitroanilide and it sustained 50 % activity after 1 h incubation at 50 °C. The activity of rLap1 was significantly inhibited by EDTA, whereas Co(2+), Mn(2+), and Ca(2+) ions, but not Zn(2+) ions, restored its activity. rLap1 showed the highest activity against Arg-pNA and then Leu-, Lys-, Met-, and Phe-pNA. The 3D structure of rLap1 showed it had a conserved functional charge/dipole complex and a hydrogen bond network of Zn2-D179-S228-Q177-D229-S158 around its active center. An acidic Asp residue was found at the bottom of the substrate binding pocket, which explains its preference for basic N-terminal amino acid substrates such as Arg and Lys. rLap1 improved the degree of hydrolysis of casein and soy protein hydrolysates and also decreased their bitterness, indicating its potential utility in food production.

  4. Do Teachers Misbehave? Aggression in School Teams

    ERIC Educational Resources Information Center

    Ben Sasson, Dvora; Somech, Anit

    2015-01-01

    Purpose: Despite growing research on school aggression, significant gaps remain in the authors' knowledge of team aggression, since most studies have mainly explored aggression on the part of students. The purpose of this paper is to focus on understanding the phenomenon of workplace aggression in school teams. Specifically, the purpose of the…

  5. Periodontitis and diabetes interrelationships: role of inflammation.

    PubMed

    Iacopino, A M

    2001-12-01

    Diabetes mellitus is a systemic disease with several major complications affecting both the quality and length of life. One of these complications is periodontal disease (periodontitis). Periodontitis is much more than a localized oral infection. Recent data indicate that periodontitis may cause changes in systemic physiology. The interrelationships between periodontitis and diabetes provide an example of systemic disease predisposing to oral infection, and once that infection is established, the oral infection exacerbates systemic disease. In this case, it may also be possible for the oral infection to predispose to systemic disease. In order to understand the cellular/molecular mechanisms responsible for such a cyclical association, one must identify common physiological changes associated with diabetes and periodontitis that produce a synergy when the conditions coexist. A potential mechanistic link involves the broad axis of inflammation, specifically immune cell phenotype, serum lipid levels, and tissue homeostasis. Diabetes-induced changes in immune cell function produce an inflammatory immune cell phenotype (upregulation of proinflammatory cytokines from monocytes/polymorphonuclear leukocytes and downregulation of growth factors from macrophages). This predisposes to chronic inflammation, progressive tissue breakdown, and diminished tissue repair capacity. Periodontal tissues frequently manifest these changes because they are constantly wounded by substances emanating from bacterial biofilms. Diabetic patients are prone to elevated low density lipoprotein cholesterol and triglycerides (LDL/TRG) even when blood glucose levels are well controlled. This is significant, as recent studies demonstrate that hyperlipidemia may be one of the factors associated with diabetes-induced immune cell alterations. Recent human studies have established a relationship between high serum lipid levels and periodontitis. Some evidence now suggests that periodontitis itself may

  6. Periodontal disease and diabetes mellitus

    PubMed Central

    NEGRATO, Carlos Antonio; TARZIA, Olinda; JOVANOVIČ, Lois; CHINELLATO, Luiz Eduardo Montenegro

    2013-01-01

    Periodontal disease (PD) is one of the most commonly known human chronic disorders. The relationship between PD and several systemic diseases such as diabetes mellitus (DM) has been increasingly recognized over the past decades. Objective: The purpose of this review is to provide the reader with knowledge concerning the relationship between PD and DM. Many articles have been published in the english and Portuguese literature over the last 50 years examining the relationship between these two chronic diseases. Data interpretation is often confounded by varying definitions of DM, PD and different clinical criteria were applied to determine the prevalence, extent and severity of PD, levels of glycemic control and diabetes-related complications. Methods: This paper provides a broad overview of the predominant findings from research conducted using the BBO (Bibliografia Brasileira de Odontologia), MEDLINE, LILACS and PubMed for Controlled Trials databases, in english and Portuguese languages published from 1960 to October 2012. Primary research reports on investigations of relationships between DM/DM control, PD/periodontal treatment and PD/DM/diabetes-related complications identified relevant papers and meta-analyses published in this period. Results: This paper describes the relationship between PD and DM and answers the following questions: 1- The effect of DM on PD, 2- The effects of glycemic control on PD and 3- The effects of PD on glycemic control and on diabetes-related complications. Conclusions: The scientific evidence reviewed supports diabetes having an adverse effect on periodontal health and PD having an adverse effect on glycemic control and on diabetes-related complications. Further research is needed to clarify these relationships and larger, prospective, controlled trials with ethnically diverse populations are warranted to establish that treating PD can positively influence glycemic control and possibly reduce the burden of diabetes

  7. Systemic antibiotic therapy in periodontics

    PubMed Central

    Kapoor, Anoop; Malhotra, Ranjan; Grover, Vishakha; Grover, Deepak

    2012-01-01

    Systemic antibiotics in conjunction with scaling and root planing (SRP), can offer an additional benefit over SRP alone in the treatment of periodontitis, in terms of clinical attachment loss (CAL) and pocket depth change, and reduced risk of additional CAL loss. However, antibiotics are not innocuous drugs. Their use should be justified on the basis of a clearly established need and should not be substituted for adequate local treatment. The aim of this review is to discuss the rationale, proper selection, dosage and duration for antibiotic therapy so as to optimize the usefulness of drug therapy. PMID:23559912

  8. Periodontal considerations in older individuals.

    PubMed

    Darby, I

    2015-03-01

    In the next few years there will be a great increase in the percentage of the population aged over 65. Not only will they have more teeth than previous generations, but also a large number of implants. The increase in age is accompanied by an increase in the prevalence and incidence of periodontal diseases. In addition, there is a decrease in manual dexterity and an increase in co-morbidity and medications affecting the oral cavity. Dental care in aged care facilities can be poor and access to dental professionals difficult. This article discusses these issues.

  9. Systemic antibiotic therapy in periodontics.

    PubMed

    Kapoor, Anoop; Malhotra, Ranjan; Grover, Vishakha; Grover, Deepak

    2012-09-01

    Systemic antibiotics in conjunction with scaling and root planing (SRP), can offer an additional benefit over SRP alone in the treatment of periodontitis, in terms of clinical attachment loss (CAL) and pocket depth change, and reduced risk of additional CAL loss. However, antibiotics are not innocuous drugs. Their use should be justified on the basis of a clearly established need and should not be substituted for adequate local treatment. The aim of this review is to discuss the rationale, proper selection, dosage and duration for antibiotic therapy so as to optimize the usefulness of drug therapy.

  10. Drug addiction and periodontal diseases

    PubMed Central

    Saini, Gurpreet Kaur; Gupta, N. D.; Prabhat, K. C.

    2013-01-01

    The prevalence of drug addiction is increasing globally. Drug abuse damages many parts of the body such as oral cavity, lungs, liver, brain, heart etc., Addicts suffer from physical, psychological, emotional and behavioral problems. Their nutrition is also compromised. There is certainly an impact of all these factors on the health of periodontium. Dentists should be aware of the effects of drugs while treating the drug addicts. This article correlates the studies done on the impact of abused drugs such as alcohol, tobacco, opiates, cannabis, amphetamines etc., on general and periodontal health. PMID:24174750

  11. Membranes for periodontal regeneration: From commercially available to spatially designed and functionally graded materials

    NASA Astrophysics Data System (ADS)

    Bottino, Marco Cicero

    The aging of the global population will lead to a considerable increase in the number of surgical and restorative procedures related to oral rehabilitation or periodontal regeneration. Periodontitis is one of the most aggressive pathologies that concern the integrity of the periodontal system that can lead to the destruction of the periodontium. Guided tissue and guided bone regeneration (GTR/GBR) have been used for the repair and regeneration of periodontal tissues by utilizing an occlusive membrane. The goal of this dissertation is to advance the knowledge in the area of periodontal regeneration by investigating the properties of a commercially available freeze-dried collagen-based graft (AlloDermRTM) and by designing/fabricating a functionally graded membrane (FGM) via multilayer electrospinning. The effects of different rehydration times and of a simultaneous rehydration/crosslinking procedure on the biomechanical properties and matrix stability of the commercially available membrane were investigated. The results revealed that there are significant changes on the biomechanical properties of the graft as rehydration time increases. Moreover, it was demonstrated that the simultaneous rehydration/crosslinking protocol has a synergistic effect in terms of enhancing biomechanical properties. A FGM consisting of a core-layer (CL) and two functional surface-layers (SL) was fabricated via sequential electrospinning. Hydroxyapatite nanoparticles (n-HAp) were incorporated to enhance bone formation (SL facing bone defect), and metronidazole benzoate (MET) was added to prevent bacterial colonization (SL facing the epithelial tissue). Degradation studies performed on both the CL and the FGM confirmed that the design holds promise in terms of providing the required mechanical stability to avoid membrane collapse and, therefore, enhance bone regeneration. Finally, it was demonstrated that MET incorporation into the SL that would face epithelial tissue is effective in

  12. Kindergarten Children's Genetic Vulnerabilities Interact with Friends' Aggression to Promote Children's Own Aggression

    ERIC Educational Resources Information Center

    van Lier, Pol; Boivin, Michel; Dionne, Ginette; Vitaro, Frank; Brendgen, Mara; Koot, Hans; Tremblay, Richard E.; Perusse, Daniel

    2007-01-01

    Objective: To examine whether kindergarten children's genetic liability to physically aggress moderates the contribution of friends' aggression to their aggressive behaviors. Method: Teacher and peer reports of aggression were available for 359 6-year-old twin pairs (145 MZ, 212 DZ) as well as teacher and peer reports of aggression of the two best…

  13. Ultrasonic device for measuring periodontal attachment levels

    NASA Astrophysics Data System (ADS)

    Lynch, J. E.; Hinders, M. K.

    2002-07-01

    Periodontal disease is manifested clinically by a degradation of the ligament that attaches the tooth to the bone. The most widely used diagnostic tool for assessment of periodontal diseases, measurement of periodontal attachment loss with a manual probe, may overestimate attachment loss by as much as 2 mm in untreated sites, while underestimating attachment loss by an even greater margin following treatment. Manual probing is also invasive, which causes patient discomfort. This work describes the development and testing of an ultrasonographic periodontal probe designed to replace manual probing. It uses a thin stream of water to project an ultrasonic beam into the periodontal pocket, and then measures echoes off features within the pocket. To do so, the ultrasonic beam must be narrowed from 2 (the diameter of the transducer) to 0.5 mm (the approximate width of the periodontal pocket at the gingival margin). The proper choice of transducer frequency, the proper method for controlling water flow from the probe, and a model for interpreting these echoes are also addressed. Initial results indicate that the device measures echoes from the hard tissue of the tooth surface, and that the periodontal attachment level can be inferred from these echoes.

  14. Treatment of periodontal disease in older adults.

    PubMed

    Renvert, Stefan; Persson, G Rutger

    2016-10-01

    Within the next 40 years the number of older adults worldwide will more than double. This will impact periodontal treatment needs and presents a challenge to health-care providers and governments worldwide, as severe periodontitis has been reported to be the sixth most prevalent medical condition in the world. Older adults (≥ 80 years of age) who receive regular dental care retain more teeth than those who do not receive such care, but routine general dental care for these individuals is not sufficient to prevent the progression of periodontitis with the same degree of success as in younger individuals. There is a paucity of data on the efficacy of different periodontal therapies for older individuals. However, considering the higher prevalence of chronic medical conditions seen in older adults, it cannot be assumed that periodontal therapy will yield the same degree of success seen in younger individuals. Furthermore, medications can influence the status of the periodontium and the delivery of periodontal care. As an example, anticoagulant drugs are common among older patients and may be a contraindication to certain treatments. Newer anticoagulants will, however, facilitate surgical intervention in older patients. Furthermore, prescription medications taken for chronic conditions, such as osteoporosis and cardiovascular diseases, can affect the periodontium in a variety of ways. In summary, consideration of socio-economic factors, general health status and multiple-drug therapies will, in the future, be an important part of the management of periodontitis in older adults.

  15. [Periodontal disease in pediatric rheumatic diseases].

    PubMed

    Fabri, Gisele M C; Savioli, Cynthia; Siqueira, José T; Campos, Lucia M; Bonfá, Eloisa; Silva, Clovis A

    2014-01-01

    Gingivitis and periodontitis are immunoinflammatory periodontal diseases characterized by chronic localized infections usually associated with insidious inflammation This narrative review discusses periodontal diseases and mechanisms influencing the immune response and autoimmunity in pediatric rheumatic diseases (PRD), particularly juvenile idiopathic arthritis (JIA), childhood-onset systemic lupus erythematosus (C-SLE) and juvenile dermatomyositis (JDM). Gingivitis was more frequently observed in these diseases compared to health controls, whereas periodontitis was a rare finding. In JIA patients, gingivitis and periodontitis were related to mechanical factors, chronic arthritis with functional disability, dysregulation of the immunoinflammatory response, diet and drugs, mainly corticosteroids and cyclosporine. In C-SLE, gingivitis was associated with longer disease period, high doses of corticosteroids, B-cell hyperactivation and immunoglobulin G elevation. There are scarce data on periodontal diseases in JDM population, and a unique gingival pattern, characterized by gingival erythema, capillary dilation and bush-loop formation, was observed in active patients. In conclusion, gingivitis was the most common periodontal disease in PRD. The observed association with disease activity reinforces the need for future studies to determine if resolution of this complication will influence disease course or severity.

  16. [Periodontal tissue pathology in pubertal children (pupils)].

    PubMed

    Shishniashvili, T E; Tsagareli, Z G; Gogiashvili, L E; Khimshiashvili, N B

    2012-03-01

    The study aimed at investigation of the rate of periodontal pathologies in juvenile adolescents, the analysis of the severity of the disease and detection of the correlation between the periodontal tissue pathology and hormonal status of pre-and pubertal periods. A stomatologic (dental) status of 618 pupils, 9-15 of ages in Tbilisi General Education Schools has been studied--to detect the rate and intensity of periodontal pathologies and analyze the influence of hormonal changes of juvenile periodontal tissues. According to the obtained results we can conclude that the high rate of periodontal diseases has been fixed in pre-pubertal and pubertal schoolchildren (pupils). It should be emphasized that the degree of periodontal tissue pathologies increases with age. In addition, the mentioned pathology was more frequently fixed and expressed in girls, 12-13 of ages and in boys, 14-15 of ages. Juvenile periodontal pathologies most frequently is generalized, which most frequently is aggravated with the existence of jaw-dental anomalies and the poor oral hygiene status.

  17. Periodontitis and Cognitive Decline in Alzheimer's Disease.

    PubMed

    Ide, Mark; Harris, Marina; Stevens, Annette; Sussams, Rebecca; Hopkins, Viv; Culliford, David; Fuller, James; Ibbett, Paul; Raybould, Rachel; Thomas, Rhodri; Puenter, Ursula; Teeling, Jessica; Perry, V Hugh; Holmes, Clive

    2016-01-01

    Periodontitis is common in the elderly and may become more common in Alzheimer's disease because of a reduced ability to take care of oral hygiene as the disease progresses. Elevated antibodies to periodontal bacteria are associated with an increased systemic pro-inflammatory state. Elsewhere raised serum pro-inflammatory cytokines have been associated with an increased rate of cognitive decline in Alzheimer's disease. We hypothesized that periodontitis would be associated with increased dementia severity and a more rapid cognitive decline in Alzheimer's disease. We aimed to determine if periodontitis in Alzheimer's disease is associated with both increased dementia severity and cognitive decline, and an increased systemic pro inflammatory state. In a six month observational cohort study 60 community dwelling participants with mild to moderate Alzheimer's Disease were cognitively assessed and a blood sample taken for systemic inflammatory markers. Dental health was assessed by a dental hygienist, blind to cognitive outcomes. All assessments were repeated at six months. The presence of periodontitis at baseline was not related to baseline cognitive state but was associated with a six fold increase in the rate of cognitive decline as assessed by the ADAS-cog over a six month follow up period. Periodontitis at baseline was associated with a relative increase in the pro-inflammatory state over the six month follow up period. Our data showed that periodontitis is associated with an increase in cognitive decline in Alzheimer's Disease, independent to baseline cognitive state, which may be mediated through effects on systemic inflammation.

  18. Peripheral blood monocyte responses in periodontitis.

    PubMed

    Fokkema, S J

    2012-08-01

    Periodontitis results from the interaction of bacteria on the tooth surfaces and the host immune response. Although periodontal pathogens are essential for the initiation and progression of the disease, the tissue damage in periodontitis is primarily mediated by the host immune response. Differences in the susceptibility to the disease and in the clinal outcome of the therapy seem to be less dependent on genetics but more on lifestyle factors, like smoking, overweight, stress and nutrition. It has been shown that these lifestyle factors may modulate the immune response and therefore influence the initiation and progression of the disease. To study the host immune response, whole blood cell cultures (WBCC) stimulated with lipopolysaccharide (LPS) have been widely used and they specifically reflect the behaviour of monocytes. It has been shown that peripheral blood monocytes in LPS-stimulated WBCC from non-smoking periodontitis patients display a T-helper 2 (Th2)-promoting phenotype in comparison with controls. After periodontal therapy, this phenotype reversed and was comparable with controls. However, in smoking but treated patients, the Th2-promoting phenotype of monocytes still remained. Therefore, the aberrant phenotype of monocytes in the peripheral blood from periodontitis patients is likely to be a systemic response to exogenous and endogenous danger molecules released or induced by the periodontal infection or by smoking. It can be concluded that periodontal therapy in non-smoking periodontitis patients has beneficial health effects and that smoking cessation should be an integral part of the therapy as well for general health reasons as for the clinical outcome.

  19. Effect of non-surgical periodontal treatment on transferrin serum levels in patients with chronic periodontitis

    PubMed Central

    Shirmohamadi, Adileh; Chitsazi, Mohamad Taghi; Faramarzi, Masoumeh; Salari, Ashkan; Naser Alavi, Fereshteh; Pashazadeh, Nazila

    2016-01-01

    Background. Transferrin is a negative acute phase protein, which decreases during inflammation and infection. The aim of the present investigation was to evaluate changes in the transferrin serum levels subsequent to non-surgical treatment of chronic periodontal disease. Methods. Twenty patients with chronic periodontitis and 20 systemically healthy subjects without periodontal disease, who had referred to Tabriz Faculty of Dentistry, were selected. Transferrin serum levels and clinical periodontal parameters (pocket depth, clinical attachment level, gingival index, bleeding index and plaque index) were measured at baseline and 3 months after non-surgical periodontal treatment. Data were analyzed with descriptive statistical methods (means ± standard deviations). Independent samples t-test was used to compare transferrin serum levels and clinical variables between the test and control groups. Paired samples t-test was used in the test group for comparisons before and after treatment. Statistical significance was set at P < 0.05. Results. The mean transferrin serum level in patients with chronic periodontitis (213.1 ± 9.2 mg/dL) was significantly less than that in periodontally healthy subjects (307.8 ± 11.7 mg/dL). Three months after periodontal treatment, the transferrin serum level increased significantly (298.3 ± 7.6 mg/dL) and approached the levels in periodontally healthy subjects (P < 0.05). Conclusion. The decrease and increase in transferrin serum levels with periodontal disease and periodontal treatment, respectively, indicated an inverse relationship between transferrin serum levels and chronic periodontitis. PMID:27651883

  20. Labial piercing and localized periodontal destruction - partial periodontal regeneration following periodontal debridement and free gingival graft.

    PubMed

    Kapferer, Ines; Hienz, Stefan; Ulm, Christian

    2008-02-01

    Localized periodontal destruction has been reported as a rare complication of intraoral piercings. The purpose of this case report was to illustrate the destructive nature of a lip stud and to describe the successful treatment of this case. The lip stud was removed and supra- and subgingival debridement was performed. Because of a shallow vestibule, the absence of keratinized gingiva, and the strong frenulum insertion at the gingival margins, a free gingival graft was placed. Subsequently the patient demonstrated a significant amount of osseous regeneration and partial coverage of the recession, which has been clinically and radiographically (computed tomography) documented.

  1. Reactive oxygen species in periodontitis

    PubMed Central

    Dahiya, Parveen; Kamal, Reet; Gupta, Rajan; Bhardwaj, Rohit; Chaudhary, Karun; Kaur, Simerpreet

    2013-01-01

    Recent epidemiological studies reveal that more than two-third of the world's population suffers from one of the chronic forms of periodontal disease. The primary etiological agent of this inflammatory disease is a polymicrobial complex, predominantly Gram negative anaerobic or facultative bacteria within the sub-gingival biofilm. These bacterial species initiate the production of various cytokines such as interleukin-8 and TNF-α, further causing an increase in number and activity of polymorphonucleocytes (PMN) along with these cytokines, PMNs also produce reactive oxygen species (ROS) superoxide via the respiratory burst mechanism as the part of the defence response to infection. ROS just like the interleukins have deleterious effects on tissue cells when produced in excess. To counter the harmful effects of ROS, human body has its own defence mechanisms to eliminate them as soon as they are formed. The aim of this review is to focus on the role of different free radicals, ROS, and antioxidants in the pathophysiology of periodontal tissue destruction. PMID:24174716

  2. Neutrophil Functions in Periodontal Homeostasis.

    PubMed

    Cortés-Vieyra, Ricarda; Rosales, Carlos; Uribe-Querol, Eileen

    2016-01-01

    Oral tissues are constantly exposed to damage from the mechanical effort of eating and to microorganisms, mostly bacteria. In healthy gingiva tissue remodeling and a balance between bacteria and innate immune cells are maintained. However, excess of bacteria biofilm (plaque) creates an inflammation state that recruits more immune cells, mainly neutrophils to the gingiva. Neutrophils create a barrier for bacteria to reach inside tissues. When neutrophils are insufficient, bacteria thrive causing more inflammation that has been associated with systemic effects on other conditions such as atherosclerosis, diabetes, and cancer. But paradoxically when neutrophils persist, they can also promote a chronic inflammatory state that leads to periodontitis, a condition that leads to damage of the bone-supporting tissues. In periodontitis, bone loss is a serious complication. How a neutrophil balance is needed for maintaining healthy oral tissues is the focus of this review. We present recent evidence on how alterations in neutrophil number and function can lead to inflammatory bone loss, and how some oral bacteria signal neutrophils to block their antimicrobial functions and promote an inflammatory state. Also, based on this new information, novel therapeutic approaches are discussed.

  3. Neutrophil Functions in Periodontal Homeostasis

    PubMed Central

    Cortés-Vieyra, Ricarda; Rosales, Carlos

    2016-01-01

    Oral tissues are constantly exposed to damage from the mechanical effort of eating and to microorganisms, mostly bacteria. In healthy gingiva tissue remodeling and a balance between bacteria and innate immune cells are maintained. However, excess of bacteria biofilm (plaque) creates an inflammation state that recruits more immune cells, mainly neutrophils to the gingiva. Neutrophils create a barrier for bacteria to reach inside tissues. When neutrophils are insufficient, bacteria thrive causing more inflammation that has been associated with systemic effects on other conditions such as atherosclerosis, diabetes, and cancer. But paradoxically when neutrophils persist, they can also promote a chronic inflammatory state that leads to periodontitis, a condition that leads to damage of the bone-supporting tissues. In periodontitis, bone loss is a serious complication. How a neutrophil balance is needed for maintaining healthy oral tissues is the focus of this review. We present recent evidence on how alterations in neutrophil number and function can lead to inflammatory bone loss, and how some oral bacteria signal neutrophils to block their antimicrobial functions and promote an inflammatory state. Also, based on this new information, novel therapeutic approaches are discussed. PMID:27019855

  4. Regenerative therapy: a periodontal-endodontic perspective.

    PubMed

    Kinaia, Bassam Michael; Chogle, Sami M A; Kinaia, Atheel M; Goodis, Harold E

    2012-07-01

    Periodontal and endodontic diseases are inflammatory responses leading to periodontal and pulpal tissue loss. Regenerative therapies aim to restore the lost structures to vitality and function. Various materials and treatments methods have been used such as bone grafts, guided tissue regeneration, enamel matrix derivatives, growth and differentiation factors, and stem cells. Although the current materials and methods demonstrated adequate clinical results, true and complete biological tissue regeneration is not yet attainable. The current article reviews chronologically the materials and methods used in periodontal and endodontic regeneration highlighting their clinical success and shortcomings, and discussing future directions in regenerative therapy.

  5. The antioxidant master glutathione and periodontal health

    PubMed Central

    Bains, Vivek Kumar; Bains, Rhythm

    2015-01-01

    Glutathione, considered to be the master antioxidant (AO), is the most-important redox regulator that controls inflammatory processes, and thus damage to the periodontium. Periodontitis patients have reduced total AO capacity in whole saliva, and lower concentrations of reduced glutathione (GSH) in serum and gingival crevicular fluid, and periodontal therapy restores the redox balance. Therapeutic considerations for the adjunctive use of glutathione in management of periodontitis, in limiting the tissue damage associated with oxidative stress, and enhancing wound healing cannot be underestimated, but need to be evaluated further through multi-centered randomized controlled trials. PMID:26604952

  6. Is periodontal disease during orthodontics preventable?

    PubMed

    Vaughan, O B

    1990-01-01

    Periodontal disease during orthodontic therapy is preventable and is controllable and in continuous studies after orthodontic therapy has been completed, it has been shown that under the properly controlled regimen of treatment the destruction to the periodontal tissues of the teeth is not accentuated to a statistically significant degree as greater than that which occurs during the same interim without orthodontic therapy. This encourages us; however, the difficulties cited in the paper above challenges us and our finest professional skills in the proper care of the orthodontic patients with periodontal complications.

  7. Prevalence of periodontal pathogens as predictor of the evolution of periodontal status.

    PubMed

    Puig-Silla, Miriam; Montiel-Company, José María; Dasí-Fernández, Francisco; Almerich-Silla, José Manuel

    2016-11-25

    The aim of this study was to determine the relationship between the prevalence of Porphyromonas gingivalis, its fimA genotypes, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Treponema denticola and the evolution of periodontal health. In a longitudinal prospective study, samples of subgingival plaque were taken from 114 patients (37 with chronic periodontitis, 17 with gingivitis, and 60 periodontally healthy) in the course of a full periodontal examination. PCR was employed to determine the presence of the periodontopathogenic bacteria. Four years later, a second examination and sample collection were performed in 90 of these patients (20 with chronic periodontitis, 12 with gingivitis, and 58 periodontally healthy). T. forsythia, P. gingivalis, and T. denticola are the most prevalent bacteria in patients with chronic periodontitis (78.4%, 62.2 y 56.8%, respectively). The P. gingivalis bacterium and its fimA genotypes I, II, and IV showed the highest correlation between the baseline and follow-up assessments. P. gingivalis fimA genotype II and T. forsythia were associated to a significant degree with unfavourable periodontal evolution. Of the variables studied, P. gingivalis fimA genotype II and T. forsythia increase the risk of an unfavourable evolution of periodontal status.

  8. Severe periodontitis is inversely associated with coffee consumption in the maintenance phase of periodontal treatment.

    PubMed

    Machida, Tatsuya; Tomofuji, Takaaki; Ekuni, Daisuke; Azuma, Tetsuji; Takeuchi, Noriko; Maruyama, Takayuki; Mizutani, Shinsuke; Kataoka, Kota; Kawabata, Yuya; Morita, Manabu

    2014-10-21

    This cross-sectional study addressed the relationship between coffee consumption and periodontitis in patients during the maintenance phase of periodontal treatment. A total of 414 periodontitis patients in the maintenance phase of periodontal treatment completed a questionnaire including items related to coffee intake and underwent periodontal examination. Logistic regression analysis showed that presence of moderate/severe periodontitis was correlated with presence of hypertension (Odds Ratio (OR) = 1.99, p < 0.05), smoking (former, OR = 5.63, p < 0.01; current, OR = 6.81, p = 0.076), number of teeth present (OR = 0.89, p < 0.001), plaque control record ≥20% (OR = 1.88, p < 0.05), and duration of maintenance phase (OR = 1.07, p < 0.01). On the other hand, presence of severe periodontitis was correlated with smoking (former, OR = 1.35, p = 0.501; current, OR = 3.98, p < 0.05), coffee consumption (≥1 cup/day, OR = 0.55, p < 0.05), number of teeth present (OR = 0.95, p < 0.05), and bleeding on probing ≥ 20% (OR = 3.67, p < 0.001). There appears to be an inverse association between coffee consumption (≥1 cup/day) and prevalence of severe periodontitis in the maintenance phase of periodontal treatment.

  9. Prevalence of Clinical Periodontitis and Putative Periodontal Pathogens among South Indian Pregnant Women

    PubMed Central

    Tellapragada, Chaitanya; Eshwara, Vandana Kalwaje; Acharya, Shashidhar; Bhat, Parvati; Kamath, Asha; Vishwanath, Shashidhar; Mukhopadhyay, Chiranjay

    2014-01-01

    In view of recent understanding of the association of periodontal infections and adverse pregnancy outcomes, the present investigation was undertaken to study the periodontal infections among 390 asymptomatic pregnant women and to find an association of bacterial etiologies with the disease. Prevalence of gingivitis was 38% and clinical periodontitis was 10% among the study population. Subgingival plaque specimens were subjected to multiplex PCR targeting ten putative periodontopathogenic bacteria. Among the periodontitis group, high detection rates of Porphyromonas gingivalis (56%), Prevotella nigrescens (44%), Treponema denticola (32%), and Prevotella intermedius (24%) were noted along with significant association with the disease (P < 0.05). PMID:24899898

  10. [Therapeutic Aggressiveness and Liquid Oncology].

    PubMed

    Barón Duarte, F J; Rodríguez Calvo, M S; Amor Pan, J R

    2017-01-01

    Aggressiveness criteria proposed in the scientific literature a decade ago provide a quality judgment and are a reference in the care of patients with advanced cancer, but their use is not generalized in the evaluation of Oncology Services. In this paper we analyze the therapeutic aggressiveness, according to standard criteria, in 1.001 patients with advanced cancer who died in our Institution between 2010 and 2013. The results seem to show that aggressiveness at the end of life is present more frequently than experts recommend. About 25% of patients fulfill at least one criterion of aggressiveness. This result could be explained by a liquid Oncology which does not prioritize the patient as a moral subject in the clinical appointment. Medical care is oriented to necessities and must be articulated in a model focused on dignity and communication. Its implementation through Advanced Care Planning, consideration of patient's values and preferences, and Limitation of therapeutic effort are ways to reduce aggressiveness and improve clinical practice at the end of life. We need to encourage synergic and proactive attitudes, adding the best of cancer research with the best clinical care for the benefit of human being, moral subject and main goal of Medicine.

  11. Results of uniaxial and biaxial tests on riveted fuselage lap joint specimens

    NASA Technical Reports Server (NTRS)

    Vlieger, H.

    1994-01-01

    As part of an FAA-NLR collaborative program on structural integrity of aging aircraft, NLR carried out uniaxial and biaxial fatigue tests on riveted lap joint specimens being representative for application in a fuselage. All tests were constant amplitude tests with maximum stresses being representative for fuselage pressurization cycles and R-values of 0.1. The parameters selected in the testing program were the stress level (sigma(sub max) = 14 and 16 ksi) and the rivet spacing (0.75 and 1.0 inch). All specimens contained 3 rows of countersunk rivets, the rivet row spacing was 1 inch and the rivet orientation continuous.

  12. Wear residue from polishing sapphire with silica aquasol on a tin lap

    NASA Astrophysics Data System (ADS)

    Werner, Joachim; Weis, Olaf

    1994-08-01

    Sapphire can be superpolished with a tin lap and aqueous colloidal silica as a polishing liquid. We present investigations of the polishing residue that was enriched in a special wearing mill. Elemental analysis, X-ray analysis by diffraction and MAS-NMR studies were performed to obtain an understanding of the microscopic polishing mechanism. We conclude that sapphire is abraded atom by atom in this polishing procedure and that the abraded aluminum atoms are finally chemically bonded in the colloidal silica clusters, in contrast to models proposed earlier.

  13. Correlation of field injuries and GM hybrid III dummy responses for lap-shoulder belt restraint.

    PubMed

    Nyquist, G W; Begman, P C; King, A I; Mertz, H J

    1980-05-01

    Simulated frontal, lap-shoulder belted, barrier impact tests were performed using a Volvo sedan and General Motors Hybrid III anthropomorphic test dummy. Swedish field accident injury data for this vehicle are available from another published study. For the purpose of this program, the injuries were logically subdivided into four body regions: head, neck, thorax, and lower torso. The Hybrid III has instrumentation in each of these regions. The results of three replicated tests at barrier equivalent velocities of nominally 32 and 48 km/h are discussed in terms of the field injuries, thereby providing a basis for more intelligent interpretation of future Hybrid III test results.

  14. An artifical corrosion protocol for lap-splices in aircraft skin

    NASA Technical Reports Server (NTRS)

    Shaw, Bevil J.

    1994-01-01

    This paper reviews the progress to date to formulate an artificial corrosion protocol for the Tinker AFB C/KC-135 Corrosion Fatigue Round Robin Test Program. The project has provided new test methods to faithfully reproduce the corrosion damage within a lap-splice by accelerated means, the rationale for a new laboratory test environment, and a means for corrosion damage quantification. The approach is pragmatic and the resulting artificial corrosion protocol lays the foundation for future research in the assessment of aerospace alloys. The general means for quantification of corrosion damage has been presented in a form which can be directly applied to structural integrity calculations.

  15. Bolted Double-Lap Composite Joints Under Mechanical and Thermal Loading

    NASA Technical Reports Server (NTRS)

    Kradinov, V.; Barut, A.; Madenci, E.; Walker, Sandra P. (Technical Monitor)

    2000-01-01

    This study concerns the determination of the contact stresses and contact region around bolt holes and the bolt load distribution in single- and double-lap joints of composite laminates with arbitrarily located bolts under general mechanical loading conditions and uniform temperature change. The unknown contact stress distribution and contact region between the bolt and laminates and the interaction among the bolts require the bolt load distribution, as well as the contact stresses, to be as part of the solution. The present method is based on the complex potential theory and the variational formulation in order to account for bolt stiffness, bolt-hole clearance, and finite geometry of the composite laminates.

  16. Some Observations on the Behaviour of Superimposed and Lap Sewn Joints

    DTIC Science & Technology

    1975-02-01

    Fig. 1a); Ferrier used this configuration in some of his work. The sideways loading is omitted but part of the restraint due to sewing is present. The...reminder of the joints mentioned in section 3.2 and the lap joints (sectiou 3.3). While the work was in progress, a Monsanto Tensometer E testing...the remaining samples part of the stitching broke and then the webbing failed near one end of the ocitched length. With the shorter stitched lengths it

  17. The Trimeric Model: A New Model of Periodontal Treatment Planning

    PubMed Central

    Tarakji, Bassel

    2014-01-01

    Treatment of periodontal disease is a complex and multidisciplinary procedure, requiring periodontal, surgical, restorative, and orthodontic treatment modalities. Several authors attempted to formulate models for periodontal treatment that orders the treatment steps in a logical and easy to remember manner. In this article, we discuss two models of periodontal treatment planning from two of the most well-known textbook in the specialty of periodontics internationally. Then modify them to arrive at a new model of periodontal treatment planning, The Trimeric Model. Adding restorative and orthodontic interrelationships with periodontal treatment allows us to expand this model into the Extended Trimeric Model of periodontal treatment planning. These models will provide a logical framework and a clear order of the treatment of periodontal disease for general practitioners and periodontists alike. PMID:25177662

  18. Supportive periodontal therapy and periodontal biotype as prognostic factors in implants placed in patients with a history of periodontitis

    PubMed Central

    Vallejo-Aisa, Francisco J.; Estefanía-Fresco, Ruth

    2013-01-01

    Objectives: To evaluate bone loss around implants placed in patients with a history of treated chronic periodontitis and who did or did not attend supportive periodontal therapy, after one year in function. Furthermore, the influence of periodontal biotype and level of plaque was also evaluated. Material and Methods: Forty-nine patients participated voluntarily in the study. All subjects had a history of chronic periodontitis, which had been previously treated. After the active treatment, 27 patients attended supportive periodontal therapy (SPT) and the rest did not (No SPT). The O’Leary plaque index and periodontal biotype were recorded for each subject and 246 Astra Tech® OsseospeedTM implants were radiographically analysed (123 placed in SPT patients and 123 in No SPT patients) at the time of loading and one year later, measuring marginal bone loss with the program Dental Studio NX 6.0®. The statistical analysis was performed with Windows SPSS, applying Pearson’s correlation index and the Kruskal-Wallis and U-Mann Whitney non-parametric tests. Results: Six patients were found to have periimplantitis and sixteen mucositis. The survival rate was 99.59% (100% SPT and 99.18% No SPT). Mean bone loss was 0.39 mm (range [-0.71 - 8.05]). Among SPT patients, 95% of the implants had losses less than or equal to the mean (mean bone loss of 0.16 mm) compared to 53.7% for the No SPT group (mean bone loss of 0.62 mm). A statistically significant relationship was demonstrated between bone loss around the implant and the patient’s periodontal biotype and plaque index. Conclusions: The marginal bone loss around implants in patients with treated chronic periodontitis is minimal if they are in a controlled SPT programme and there is individual control of plaque index. Moreover, the presence of a thin periodontal biotype represents a risk factor for additional bone loss. Key words:Peri-implantitis, chronic periodontitis, bacterial plaque, periodontal biotype. PMID:23722147

  19. Interfacial and Mechanical Behavior of AA5456 Filling Friction-Stir-Welded Lap Joints Using Similar and Dissimilar Pins

    NASA Astrophysics Data System (ADS)

    Behmand, Saleh Alaei; Mirsalehi, Seyyed Ehsan; Omidvar, Hamid; Safarkhanian, Mohammad Ali

    2016-10-01

    In this article, filling friction stir welding (FFSW) of the remaining exit holes of AA5456 alloy friction-stir-welded lap joints was studied. For this purpose, the influences of different rotating speeds, holding times, and pin materials, AA5456 and AA2024, on the metallurgical structure and joint strength were investigated. The observations showed that defect-free lap joints are successfully obtainable by this method using similar and dissimilar consumable pins. The results indicated that the higher rotating speed and holding time adversely affect the weld performance. The best result was achieved for 30 seconds holding time, 500 rpm rotating speed, and AA2024 consumable pin. In this condition, a lap shear strength of 10 pct higher than that of the nonfilled joint, equivalent to about 94 pct of the original defect-free FSW joint, was obtained, whereas the GTAW filled joint showed only approximately 87 pct of the continuous FSW joint strength.

  20. Acute cervical spinal cord injury secondary to air bag deployment without proper use of lap or shoulder harnesses.

    PubMed

    Hart, R A; Mayberry, J C; Herzberg, A M

    2000-02-01

    The authors present a case report of a patient with cervical central spinal cord syndrome caused by a hyperextension injury after a motor vehicle collision in which the air bag deployed in the absence of shoulder or lap belt harnesses. The potential for cervical spine and spinal cord hyperextension injuries in passengers positioned in front of air bags without proper use of shoulder or lap belt harnesses is discussed. Cervical central spinal cord quadriplegia occurred with cervical spondylosis and kyphosis that was managed by early three-level cervical corpectomy in a 58-year-old patient. Early improvement in the patient's neurological status occurred but was incomplete at the time of this report. Cervical hyperextension injuries are possible in passengers positioned in the front seat of cars with air bags when shoulder or lap belt harnesses are not used properly. Previous biomechanical studies have documented the potential for these types of injuries.

  1. L-Cysteine and L-AP4 microinjections in the rat caudal ventrolateral medulla decrease arterial blood pressure.

    PubMed

    Takemoto, Yumi

    2014-12-01

    The thiol amino acid L-cysteine increases arterial blood pressure (ABP) when injected into the cerebrospinal fluid space in conscious rats, indicating a pressor response to centrally acting L-cysteine. A prior synaptic membrane binding assay suggests that L-cysteine has a strong affinity for the L-2-amino-4-phosphonobutyric acid (L-AP4) binding site. The central action of L-cysteine may be vial-AP4 sensitive receptors. The present study investigated cardiovascular responses to L-cysteine and L-ap4 microinjected into the autonomic area of the caudal ventrolateral medulla (CVLM) where inhibitory neurons regulate ABP via pre-sympathetic vasomotor neurons. Both the injection of L-cysteine and L-AP4 in the CVLM sites identified with L-glutamate produced the same depressor and bradycardic responses in urethane-anesthetized rats. Neither a prior antagonist microinjection of MK801 for the N-methyl-D-aspartate (NMDA) receptor nor CNQX for the non-NMDA receptor attenuated the responses to L-cysteine, but the combination of the two receptor blocking with an additional prior injection abolished the response. In contrast, either receptor blockade alone abolished the response to L-AP4, indicating distinct mechanisms between responses to L-cysteine and L-AP4 in the CVLM. The results indicate that the CVLM is a central active site for L-cysteine's cardiovascular response. Central L-cysteine's action could be independent of the L-AP4 sensitive receptors. Cardiovascular regulation may involve endogenous L-cysteine in the CVLM. Further multidisciplinary examinations are required to elaborate on L-cysteine's functional roles in the CVLM.

  2. Combining FoxP3 and Helios with GARP/LAP markers can identify expanded Treg subsets in cancer patients.

    PubMed

    Abd Al Samid, May; Chaudhary, Belal; Khaled, Yazan S; Ammori, Basil J; Elkord, Eyad

    2016-03-22

    Regulatory T cells (Tregs) comprise numerous heterogeneous subsets with distinct phenotypic and functional features. Identifying Treg markers is critical to investigate the role and clinical impact of various Treg subsets in pathological settings, and also for developing more effective immunotherapies. We have recently shown that non-activated FoxP3-Helios+ and activated FoxP3+/-Helios+ CD4+ T cells express GARP/LAP immunosuppressive markers in healthy donors. In this study we report similar observations in the peripheral blood of patients with pancreatic cancer (PC) and liver metastases from colorectal cancer (LICRC). Comparing levels of different Treg subpopulations in cancer patients and controls, we report that in PC patients, and unlike LICRC patients, there was no increase in Treg levels as defined by FoxP3 and Helios. However, defining Tregs based on GARP/LAP expression showed that FoxP3-LAP+ Tregs in non-activated and activated settings, and FoxP3+Helios+GARP+LAP+ activated Tregs were significantly increased in both groups of patients, compared with controls. This work implies that a combination of Treg-specific markers could be used to more accurately determine expanded Treg subsets and to understand their contribution in cancer settings. Additionally, GARP-/+LAP+ CD4+ T cells made IL-10, and not IFN-γ, and levels of IL-10-secreting CD4+ T cells were elevated in LICRC patients, especially with higher tumor staging. Taken together, our results indicate that investigations of Treg levels in different cancers should consider diverse Treg-related markers such as GARP, LAP, Helios, and others and not only FoxP3 as a sole Treg-specific marker.

  3. Impaired Circulating CD4+LAP+ Regulatory T Cells in Patients with Acute Coronary Syndrome and Its Mechanistic Study

    PubMed Central

    Mao, Xiao-Bo; Yu, Kun-Wu; Zhang, Wei; Zhu, Peng-Fei; Ren, Ze-Peng; Wu, Bang-Wei; Ji, Qin-Wei; Wang, Xiang; Zeng, Qiu-Tang

    2014-01-01

    Objective CD4+ latency-associated peptide (LAP)+ regulatory T cells (Tregs) are a newly discovered T cell subset in humans and the role of these cells in patients with acute coronary syndrome (ACS) has not been explored. We designed to investigate whether circulating frequency and function of CD4+LAP+ Tregs are defective in ACS. Methods One hundred eleven ACS patients (acute myocardial infarction and unstable angina) and 117 control patients were enrolled in the study. The control patients consisted of chronic stable angina (CSA) and chest pain syndrome (CPS). The frequencies of circulating CD4+LAP+ Tregs and the expression of the transmembrane protein glycoprotein-A repetitions predominant (GARP) on CD4+ T cells were determined by flow cytometry. The function of CD4+LAP+ Tregs was detected using thymidine uptake. Serum interleukin-10 (IL-10) and transforming growth factor-β protein (TGF-β) levels were detected using ELISA and expression of GARP mRNA in peripheral blood mononuclear cells (PBMCs) was measured by real time-polymerase chain reaction. Results We found ACS patients had a significantly lower frequency of circulating CD4+LAP+ Tregs, and the function of these cells was reduced compared to controls. The expression of GARP in CD4+ T cells and the serum levels of TGF-β in ACS patients were lower than those of control patients. The serum levels of IL-10 were similar between the two cohorts. Conclusions A novel regulatory T cell subset, defined as CD4+LAP+ T cells is defective in ACS patients. PMID:24558424

  4. Epigenetics and Periodontitis: A Contemporary Review

    PubMed Central

    Cherukuri, Sandhya; Namasivayam, Ambalavanan

    2016-01-01

    Periodontitis is characterized by infection and inflammation of the tooth supporting structures. Few signs of susceptibility and recurrence after treatment are seen due to the outgrowth of various pathogenic microorganisms. Many studies have been done to understand the genetic basis of periodontal disease. An increased risk for periodontitis has been shown with the variations in genes related to the inflammatory response. Interestingly, some of the genes regulated by epigenetic modifications are modified in response to environmental stimuli. Conditions such as cancer, autoimmune or inflammatory diseases have been dispensed by epigenetic mechanisms. The understanding of these molecular mechanisms and the early detection of susceptibility may guide in future periodontal disease treatment and prevention. PMID:28050521

  5. Optical coherence tomography for diagnosing periodontal disease

    NASA Astrophysics Data System (ADS)

    Colston, Bill W., Jr.; Everett, Matthew J.; Da Silva, Luiz B.; Otis, Linda L.; Nathel, Howard

    1997-05-01

    We have, in this preliminary study, investigated the use of optical coherence tomography for diagnosis of periodontal disease. We took in vitro OCT images of the dental and periodontal tissues from a young pig and compared them to histological sections. These images distinguish tooth and soft tissue relationships that are important in diagnosing and assessing periodontal disease. We have imaged the attachment of gingiva to the tooth surface and located the cemento-enamel junction. This junction is an important reference point for defining attachment level in the diagnosis of periodontal disease. the boundary between enamel and dentin is also visible for most of the length of the anatomical crown, allowing quantitation of enamel thickness and character.

  6. The association between rheumatoid arthritis and periodontitis.

    PubMed

    Leech, Michelle T; Bartold, P M

    2015-04-01

    The relationship between rheumatoid arthritis and poor oral health has been recognised for many decades. The association between periodontal infection and the risk of developing RA has been the subject of epidemiological, clinical and basic science research in recent times. Converging and reproducible evidence now makes a clear case for the role of specific periodontal infective pathogens in initiating, amplifying and perpetuating rheumatoid arthritis. The unique enzymatic properties of the periodontal pathogen Porphyromonas gingivalis and its contribution to the burden of citrullinated peptides is now well established. The impact of localized infection such as periodontitis in shaping specific anti-citrullinated peptide immune responses highlights a key area for treatment, prevention and risk assessment in rheumatoid arthritis.

  7. Clinical periodontics with the argon laser

    NASA Astrophysics Data System (ADS)

    Finkbeiner, R. L.

    1995-04-01

    The argon laser has proven to be a valuable tool for the thermodynamic debridement of the periodontal lesion, incisions and tissue fusion. Illustrations of clinical applications and discussion of laser parameters will be provided.

  8. Periodontal Considerations for the Child and Adolescent. A Literature Review.

    PubMed

    Lin, Guo-Hao; Boynton, James R

    2015-01-01

    The primary etiology of periodontal disease is bacterial plaque and its byproducts in a susceptible host. Although the prevalence of plaque-induced periodontal disease is relatively low for the child and adolescent, destructive periodontal disease may be a manifestation of an underlying systemic disease. In some cases, childhood periodontal destruction may be the first sign of systemic disease, making appropriate recognition and determination of etiology critical in this population. Therefore, this literature review discusses the periodontal considerations for the child and adolescent patient, aiming to offer a guide for differential diagnosis and oral management of periodontal disease in the young population.

  9. Potential for Stem Cell-Based Periodontal Therapy.

    PubMed

    Bassir, Seyed Hossein; Wisitrasameewong, Wichaya; Raanan, Justin; Ghaffarigarakani, Sasan; Chung, Jamie; Freire, Marcelo; Andrada, Luciano C; Intini, Giuseppe

    2016-01-01

    Periodontal diseases are highly prevalent and are linked to several systemic diseases. The goal of periodontal treatment is to halt the progression of the disease and regenerate the damaged tissue. However, achieving complete and functional periodontal regeneration is challenging because the periodontium is a complex apparatus composed of different tissues, including bone, cementum, and periodontal ligament. Stem cells may represent an effective therapeutic tool for periodontal regeneration due to their plasticity and their ability to regenerate different tissues. This review presents and critically analyzes the available information on stem cell-based therapy for the regeneration of periodontal tissues and suggests new avenues for the development of more effective therapeutic protocols.

  10. Periodontal ligament stem cells: an update and perspectives.

    PubMed

    Chamila Prageeth Pandula, P K; Samaranayake, L P; Jin, L J; Zhang, Chengfei

    2014-05-01

    Chronic periodontitis is a serious infectious and inflammatory oral disease of humans worldwide. Conventional treatment modalities are effective for controlling periodontal disease. However, the regeneration of damaged periodontal tissues remains a major challenge in clinical practice due to the complex structure of the periodontium. Stem cell-based regenerative approaches combined with the usage of emerging biomaterials are entering a new era in periodontal regeneration. The present review updates the current knowledge of periodontal ligament stem cell-based approaches for periodontal regeneration, and elaborates on the potentials for clinical application.

  11. [The use of Emdogain in periodontal and osseous regeneration].

    PubMed

    Sculean, Anton; Rathe, Florian; Junker, Rüdiger; Becker, Jürgen; Schwarz, Frank; Arweiler, Nicole

    2007-01-01

    The goal of regenerative periodontal therapy is the reconstitution of the lost periodontal structures (i. e. the new formation of root cementum, periodontal ligament and alveolar bone). Results from basic research have pointed to the important role of an enamel matrix protein derivative (EMD) in periodontal wound healing. Histological results from experiments in animals and from human case reports have shown that treatment with EMD promotes periodontal regeneration. Moreover, clinical studies have indicated that treatment with EMD positively influences periodontal wound healing in humans. The goal of the current overview is to present the clinical indications for regenerative therapy with EMD based on the existing evidence.

  12. Parameter on periodontal maintenance. American Academy of Periodontology.

    PubMed

    2000-05-01

    The American Academy of Periodontology has developed the following parameter on Periodontal Maintenance. Periodontal maintenance is an integral part of periodontal therapy for patients with a history of inflammatory periodontal diseases. Patients should be informed of the disease process, therapeutic alternatives, potential complications, expected results, and their responsibility in treatment. Consequences of no treatment should be explained. Failure to comply with a periodontal maintenance program may result in recurrence or progression of the disease process. Given this information, patients should then be able to make informed decisions regarding their periodontal therapy.

  13. Oxidative Stress and Periodontal Disease in Obesity.

    PubMed

    Dursun, Erhan; Akalin, Ferda Alev; Genc, Tolga; Cinar, Nese; Erel, Ozcan; Yildiz, Bulent Okan

    2016-03-01

    Periodontal disease is a chronic inflammatory disease of the jaws and is more prevalent in obesity. Local and systemic oxidative stress may be an early link between periodontal disease and obesity. The primary aim of this study was to detect whether increased periodontal disease susceptibility in obese individuals is associated with local and systemic oxidative stress. Accordingly; we analyzed periodontal status and systemic (serum) and local (gingival crevicular fluid [GCF]) oxidative status markers in young obese women in comparison with age-matched lean women.Twenty obese and 20 lean women participated. Periodontal condition was determined by clinical periodontal indices including probing depth, clinical attachment level, gingival index, gingival bleeding index, and plaque index. Anthropometric, hormonal, and metabolic measurements were also performed. Blood and GCF sampling was performed at the same time after an overnight fasting. Serum and GCF total antioxidant capacity (TAOC), and total oxidant status (TOS) levels were determined, and oxidative stress index (OSI) was calculated.Clinical periodontal analyses showed higher gingival index and gingival bleeding index in the obese group (P = 0.001 for both) with no significant difference in probing depth, clinical attachment level, and plaque index between the obese and the lean women. Oxidant status analyses revealed lower GCF and serum TAOC, and higher GCF and serum OSI values in the obese women (P < 0.05 for all). GCF TOS was higher in the obese women (P < 0.05), whereas there was a nonsignificant trend for higher serum TOS in obese women (P = 0.074). GCF TAOC values showed a negative correlation with body mass index, whereas GCF OSI was positively correlated with fasting insulin and low-density lipoprotein-cholesterol levels (P < 0.05 for all). Clinical periodontal indices showed significant correlations with body mass index, insulin, and lipid levels, and also oxidant status markers

  14. Oxidative Stress and Periodontal Disease in Obesity

    PubMed Central

    Dursun, Erhan; Akalın, Ferda Alev; Genc, Tolga; Cinar, Nese; Erel, Ozcan; Yildiz, Bulent Okan

    2016-01-01

    Abstract Periodontal disease is a chronic inflammatory disease of the jaws and is more prevalent in obesity. Local and systemic oxidative stress may be an early link between periodontal disease and obesity. The primary aim of this study was to detect whether increased periodontal disease susceptibility in obese individuals is associated with local and systemic oxidative stress. Accordingly; we analyzed periodontal status and systemic (serum) and local (gingival crevicular fluid [GCF]) oxidative status markers in young obese women in comparison with age-matched lean women. Twenty obese and 20 lean women participated. Periodontal condition was determined by clinical periodontal indices including probing depth, clinical attachment level, gingival index, gingival bleeding index, and plaque index. Anthropometric, hormonal, and metabolic measurements were also performed. Blood and GCF sampling was performed at the same time after an overnight fasting. Serum and GCF total antioxidant capacity (TAOC), and total oxidant status (TOS) levels were determined, and oxidative stress index (OSI) was calculated. Clinical periodontal analyses showed higher gingival index and gingival bleeding index in the obese group (P = 0.001 for both) with no significant difference in probing depth, clinical attachment level, and plaque index between the obese and the lean women. Oxidant status analyses revealed lower GCF and serum TAOC, and higher GCF and serum OSI values in the obese women (P < 0.05 for all). GCF TOS was higher in the obese women (P < 0.05), whereas there was a nonsignificant trend for higher serum TOS in obese women (P = 0.074). GCF TAOC values showed a negative correlation with body mass index, whereas GCF OSI was positively correlated with fasting insulin and low-density lipoprotein-cholesterol levels (P < 0.05 for all). Clinical periodontal indices showed significant correlations with body mass index, insulin, and lipid levels, and also oxidant status

  15. Atomic force and super-resolution microscopy support a role for LapA as a cell-surface biofilm adhesin of Pseudomonas fluorescens

    PubMed Central

    Ivanov, Ivan E.; Boyd, Chelsea D.; Newell, Peter D.; Schwartz, Mary E.; Turnbull, Lynne; Johnson, Michael S.; Whitchurch, Cynthia B.; O’Toole, George A.; Camesano, Terri A.

    2012-01-01

    Pseudomonas fluorescence Pf0-1 requires the large repeat protein LapA for stable surface attachment. This study presents direct evidence that LapA is a cell-surface-localized adhesin. Atomic force microscopy (AFM) revealed a significant twofold reduction in adhesion force for mutants lacking the LapA protein on the cell surface compared to the wild-type strain. Deletion of lapG, a gene encoding a periplasmic cysteine protease that functions to release LapA from the cell surface, resulted in a twofold increase in the force of adhesion. Three-dimensional structured illumination microscopy (3D-SIM) revealed the presence of the LapA protein on the cell surface, consistent with its role as an adhesin. The protein is only visualized in the cytoplasm for a mutant of the ABC transporter responsible for translocating LapA to the cell surface. Together, these data highlight the power of combining the use of AFM and 3D-SIM with genetic studies to demonstrate that LapA, a member of a large group of RTX-like repeat proteins, is a cell-surface adhesin. PMID:23064158

  16. Multifrequency Eddy Current Inspection of Corrosion in Clad Aluminum Riveted Lap Joints and Its Effect on Fatigue Life

    SciTech Connect

    Okafor, A. C.; Natarajan, S.

    2007-03-21

    Aging aircraft are prone to corrosion damage and fatigue cracks in riveted lap joints of fuselage skin panels. This can cause catastrophic failure if not detected and repaired. Hence detection of corrosion damage and monitoring its effect on structural integrity are essential. This paper presents multifrequency eddy current (EC) inspection of corrosion damage and machined material loss defect in clad A1 2024-T3 riveted lap joints and its effect on fatigue life. Results of eddy current inspection, corrosion product removal and fatigue testing are presented.

  17. Optimization of geometry of elastic bodies in the vicinity of singular points on the example of an adhesive lap joint

    NASA Astrophysics Data System (ADS)

    Matveenko, V. P.; Sevodina, N. V.; Fedorov, A. Yu.

    2013-09-01

    The stress state in adhesive lap joints with various geometric shapes of spew fillet is studied. It is noted that the applied design models of the considered problem include singular points at which infinite stress values are possible if one uses the linear elasticity theory to calculate the stress state. Based on the conclusions of the solution of the geometry optimization problem in the vicinity of the singular points of elastic bodies, variants of the geometry of spew fillet, which provide the most significant decrease in the concentration of stresses in adhesive lap joints, are proposed.

  18. Quorum Sensing Inhibition, Relevance to Periodontics

    PubMed Central

    Yada, Sudheer; Kamalesh, B; Sonwane, Siddharth; Guptha, Indra; Swetha, R K

    2015-01-01

    Quorum sensing helps bacteria to communicate with each other and in coordinating their behavior. Many diseases of human beings, plants, and animals are mediated by quorum sensing. Various approaches are being tried to inhibit this communication to control the diseases caused by bacteria. Periodontal pathogens also communicate through quorum sensing and new approaches to treat periodontal disease using quorum sensing inhibition need to explored. PMID:25709373

  19. Periodontal disease may associate with breast cancer.

    PubMed

    Söder, Birgitta; Yakob, Maha; Meurman, Jukka H; Andersson, Leif C; Klinge, Björn; Söder, Per-Östen

    2011-06-01

    The main purpose was to evaluate the association between periodontal disease and the incidence of breast cancer in a prospective study of 3273 randomly selected subjects aged 30-40 years at baseline. Breast cancer incidence was registered from 1985 to 2001 according to the WHO International Classification of Diseases criteria. At baseline, 1676 individuals also underwent a clinical oral examination (Group A) whereas 1597 subjects were not clinically examined but were registered (Group B). The associations between breast cancer, periodontal disease, and missing molars were determined using multiple logistic regression models with several background variables and known risk factors for cancer. In total 26 subjects in group A and 15 subjects in group B had breast cancer. The incidence of breast cancer was 1.75% in subjects who had periodontal disease and/or any missing molars, and 0 in subjects who had periodontal disease but had no missing molars. For periodontally healthy subjects with no missing teeth the breast cancer incidence was 1%. For group B the respective incidence was 0.94%. Female gender (odds ratio (OR) 13.08) and missing any molar in the mandible (OR 2.36) were explanatory variables for breast cancer. Of the subjects with periodontal disease and any missing molars in the mandible 5.5% had breast cancer in comparison to 0.5% of the subjects who had periodontal disease but no missing molars in the mandible (P < 0.02). Chronic periodontal disease indicated by missing molars seemed to associate statistically with breast cancer.

  20. Newly Identified Pathogens Associated with Periodontitis

    PubMed Central

    Pérez-Chaparro, P.J.; Gonçalves, C.; Figueiredo, L.C.; Faveri, M.; Lobão, E.; Tamashiro, N.; Duarte, P.; Feres, M.

    2014-01-01

    There is substantial evidence supporting the role of certain oral bacteria species in the onset and progression of periodontitis. Nevertheless, results of independent-culture diagnostic methods introduced about a decade ago have pointed to the existence of new periodontal pathogens. However, the data of these studies have not been evaluated together, which may generate some misunderstanding on the actual role of these microorganisms in the etiology of periodontitis. The aim of this systematic review was to determine the current weight of evidence for newly identified periodontal pathogens based on the results of “association” studies. This review was conducted and reported in accordance with the PRISMA statement. The MEDLINE, EMBASE, and Cochrane databases were searched up to September 2013 for studies (1) comparing microbial data of subgingival plaque samples collected from subjects with periodontitis and periodontal health and (2) evaluating at least 1 microorganism other than the already-known periodontal pathogens. From 1,450 papers identified, 41 studies were eligible. The data were extracted and registered in predefined piloted forms. The results suggested that there is moderate evidence in the literature to support the association of 17 species or phylotypes from the phyla Bacteroidetes, Candidatus Saccharibacteria, Firmicutes, Proteobacteria, Spirochaetes, and Synergistetes. The phylum Candidatus Saccharibacteria and the Archaea domain also seem to have an association with disease. These data point out the importance of previously unidentified species in the etiology of periodontitis and might guide future investigations on the actual role of these suspected new pathogens in the onset and progression of this infection. PMID:25074492

  1. Evidence-based practice of periodontics.

    PubMed

    Cobb, Charles M; MacNeill, Simon R; Satheesh, Keerthana

    2010-01-01

    Evidence-based practice involves complex and conscientious decision making based not only on the available evidence but also on patient characteristics, situations, and preferences. It recognizes that care is individualized and ever-changing and involves uncertainties and probabilities. The specialty of periodontics has abundant high-level evidence upon which treatment decisions can be determined. This paper offers a brief commentary and overview of the available evidence commonly used in the private practice of periodontics.

  2. Periodontics and Oral-Systeric Relationships: Diabetes.

    PubMed

    Glascoe, Alison; Brown, Ronald; Robinson, Grace; Hailu, Kassahun

    2016-01-01

    The oral cavity is a part of the body. The health of the oral cavity affects the health of the entire body. This relationship is reciprocal, as the overall health of an individual will also affect the health of that individual's oral cavity. Periodontal disease is a common, chronic inflammatory disease affecting the supporting structures of the teeth. It has been proposed that periodontal disease is a risk factor for systemic diseases such as diabetes.

  3. Ghrelin levels in chronic periodontitis patients.

    PubMed

    Yılmaz, Gülin; Kırzıoğlu, Fatma Yeşim; Doğuç, Duygu Kumbul; Koçak, Havva; Orhan, Hikmet

    2014-01-01

    Ghrelin is a peptide hormone that has modulatory effects on the immune system. This study was designed to evaluate plasma ghrelin levels in patients with chronic periodontitis and to investigate if a relationship exists between ghrelin and periodontal parameters, serum cytokines, and bone turnover markers. Thirty-five chronic periodontitis patients (CP) and periodontal healthy individuals (C) were included in this study. Periodontal parameters were recorded. Blood samples were obtained to determine the levels of total and acylated ghrelin, interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), the soluble receptor activator nuclear factor kappaB ligand (sRANKL), alkaline phosphatase (ALP), and osteocalcin (OSC). Plasma levels of total and acylated ghrelin were significantly elevated in the CP group compared with the C group (p < 0.05). The difference was significant only between males in the two groups (groups were compared with respect to gender) (p < 0.05). There was no difference between the groups regarding the levels of serum sRANKL, TNF-α, and ALP. A relative increase in the serum levels of IL-1β and a decrease in the serum levels of OSC of the CP group were observed (p < 0.05). In addition, positive correlations between total ghrelin/ALP and total ghrelin/acylated ghrelin were discovered. We found no direct correlation between ghrelin levels and periodontal parameters. Our results indicate an increase of total and acylated ghrelin levels in patients with chronic periodontitis. Further, studies in larger populations (which could include ghrelin levels in gingival tissue, gingival crevicular fluid, and saliva) are needed in order to confirm the role of ghrelin in periodontal disease.

  4. (40)Ar/(39)Ar Age of Hornblende-Bearing R Chondrite LAP 04840

    NASA Technical Reports Server (NTRS)

    Righter, K.; Cosca, M.

    2015-01-01

    Chondrites have a complex chronology due to several variables affecting and operating on chondritic parent bodies such as radiogenic heating, pressure and temperature variation with depth, aqueous alteration, and shock or impact heating. Unbrecciated chondrites can record ages from 4.56 to 4.4 Ga that represent cooling in small parent bodies. Some brecciated chondrites exhibit younger ages (much less than 4 to 4.4 Ga) that may reflect the age of brecciation, disturbance, or shock and impact events (much less than 4 Ga). A unique R chondrite was recently found in the LaPaz Icefield of Antarctica - LAP 04840. This chondrite contains approximately 15% hornblende and trace amounts of biotite, making it the first of its kind. Studies have revealed an equigranular texture, mineral equilibria yielding equilibration near 650-700 C and 250-500 bars, hornblende that is dominantly OH-bearing (very little Cl or F), and high D/H ratios. To help gain a better understanding of the origin of this unique sample, we have measured the (40)Ar/(39)Ar age (LAP 04840 split 39).

  5. An evaluation of the blind lap joint for the surface mount attachment of chip components

    SciTech Connect

    Vianco, P T; Dal Porto, J F

    1992-01-01

    Blind lap solder joints were used to attach leadless ceramic chip resistors to polyimidequartz circuit boards. Hand soldering and vapor phase reflow techniques were evaluated. The solder was 62Sn-36Pb-2Ag (wt.%). The integrity of the solder joints was assessed by microstructural examination and room temperature shear tests. These analyses were performed on as-fabricated circuit boards as well as an those samples exposed to thermal cycling (308 cycles; {minus}55{degree} to 125{degree}C; 6{degree}C/min ramps; 120 min hold periods;) or thermal shock (100 cycles, {minus}55{degree}C to 125{degree}C; liquid-to-liquid transfer; 10 min hold periods). In all cases, microscopy revealed no cracks within the solder joints. The shear strengths of the joints were 13.4 lb (59 N), as-fabricated; 10.5 lb (47 N), 308 thermal cycles; and 14.0 lb (62 N), 100 thermal shock cycles. All values were well within acceptability limits for the particular application. Measurements of the intermetallic compound thicknesses at the copper land/solder interface indicated that the additional heating cycle of the hand soldering step decreased the layer thickness as compared to non-hand soldered joints. The successful implementation of the blind lap joint can provide increased device densities on circuit boards by reducing bonding pad extension beyond the ceramic chip foot print.

  6. Lap shear strength and healing capability of self-healing adhesive containing epoxy/mercaptan microcapsules

    NASA Astrophysics Data System (ADS)

    Ghazali, Habibah; Ye, Lin; Zhang, Ming-Qiu

    2016-03-01

    The aim of this work is to develop a self-healing polymeric adhesive formulation with epoxy/mercaptan microcapsules. Epoxy/mercaptan microcapsules were dispersed into a commercialize two-part epoxy adhesive for developing self-healing epoxy adhesive. The influence of different content of microcapsules on the shear strength and healing capability of epoxy adhesive were investigated using single-lap-joints with average thickness of adhesive layer of about 180 µm. This self-healing adhesive was used in bonding of 5000 series aluminum alloys adherents after mechanical and alkaline cleaning surface treatment. The adhesion strength was measured and presented as function of microcapsules loading. The results indicated that the virgin lap shear strength was increased by about 26% with addition of 3 wt% of self-healing microcapsules. 12% to 28% recovery of the shear strength is achieved after self-healing depending on the microcapsules content. Scanning electron microscopy was used to study fracture surface of the joints. The self-healing adhesives exhibit recovery of both cohesion and adhesion properties with room temperature healing.

  7. Laparoscopic adjustable silicone gastric banding: prospective evaluation of intragastric migration of the lap-band.

    PubMed

    Silecchia, G; Restuccia, A; Elmore, U; Polito, D; Perrotta, N; Genco, A; Bacci, V; Basso, N

    2001-08-01

    Intragastric prosthesis (Lap-Band, BioEnterics Co., Carpinteria, CA, U.S.A.) migration is one of the major long-term complications of laparoscopic adjustable silicone gastric banding. The causes, clinical signs, timing, and overall incidence of band entrapment have not been prospectively investigated in a large series. The purpose of this study was to assess prospectively the incidence of Lap-Band intragastric migration and to establish the safety and effectiveness of minimally invasive band removal. Between January 1996 and June 2000, 148 consecutive patients enrolled in a multidisciplinary bariatric program underwent laparoscopic adjustable silicone gastric banding. In the follow-up treatment, gastrointestinal endoscopy was performed routinely. One hundred twenty-three patients with a minimum follow-up period of 12 months were entered into the study group. Eleven (9.2%) patients had long-term major complications. Intragastric band migration was observed in nine (7.5%) patients. The diagnosis was established by routine endoscopy between 10 and 41 months after surgery. Five erosions occurred in the first 30 cases (learning curve period). In six patients, the band was removed by an intragastric endoscopic-assisted approach avoiding laparotomy. The remaining three patients are under endoscopic surveillance. The results of this study show that routine upper gastrointestinal endoscopy can discover asymptomatic band migrations early. Band erosion did not require emergency treatment and can be removed safely by a minimally invasive approach.

  8. Microstructure and Properties of Lap Joint Between Aluminum Alloy and Galvanized Steel by CMT

    NASA Astrophysics Data System (ADS)

    Niu, Song; Chen, Su; Dong, Honggang; Zhao, Dongsheng; Zhang, Xiaosheng; Guo, Xin; Wang, Guoqiang

    2016-05-01

    Lap joining of 1-mm-thick Novelist AC 170 PX aluminum alloy to 1.2-mm-thick ST06 Z galvanized steel sheets for automotive applications was conducted by cold metal transfer advanced welding process with ER4043 and ER4047 filler wires. Under the optimized welding parameters with ER4043 filler wire, the tensile shear strength of joint was 189 MPa, reaching 89% of the aluminum alloy base metal. Microstructure and elemental distribution were characterized by optical metalloscope and electron probe microanalysis. The lap joints with ER4043 filler wire had smaller wetting angle and longer bonded line length with better wettability than with ER4047 filler wire during welding with same parameters. The needle-like Al-Fe-Si intermetallic compounds (IMCs) were spalled into the weld and brought negative effect to the tensile strength of joints. With increasing welding current, the needle-like IMCs grew longer and spread further into the weld, which would deteriorate the tensile shear strength.

  9. Lap Shear and Impact Testing of Ochre and Beeswax in Experimental Middle Stone Age Compound Adhesives.

    PubMed

    Kozowyk, P R B; Langejans, G H J; Poulis, J A

    2016-01-01

    The production of compound adhesives using disparate ingredients is seen as some of the best evidence of advanced cognition outside of the use of symbolism. Previous field and laboratory testing of adhesives has shown the complexities involved in creating an effective Middle Stone Age glue using Acacia gum. However, it is currently unclear how efficient different adhesive recipes are, how much specific ingredients influence their performance, and how difficult it may have been for those ingredients to be combined to maximum effect. We conducted a series of laboratory-based lap shear and impact tests, following modern adhesion testing standards, to determine the efficacy of compound adhesives, with particular regard to the ingredient ratios. We tested rosin (colophony) and gum adhesives, containing additives of beeswax and ochre in varying ratios. During both lap shear and impact tests compound rosin adhesives performed better than single component rosin adhesives, and pure acacia gum was the strongest. The large difference in performance between each base adhesive and the significant changes in performance that occur due to relatively small changes in ingredient ratios lend further support to the notion that high levels of skill and knowledge were required to consistently produce the most effective adhesives.

  10. Lap Shear and Impact Testing of Ochre and Beeswax in Experimental Middle Stone Age Compound Adhesives

    PubMed Central

    2016-01-01

    The production of compound adhesives using disparate ingredients is seen as some of the best evidence of advanced cognition outside of the use of symbolism. Previous field and laboratory testing of adhesives has shown the complexities involved in creating an effective Middle Stone Age glue using Acacia gum. However, it is currently unclear how efficient different adhesive recipes are, how much specific ingredients influence their performance, and how difficult it may have been for those ingredients to be combined to maximum effect. We conducted a series of laboratory-based lap shear and impact tests, following modern adhesion testing standards, to determine the efficacy of compound adhesives, with particular regard to the ingredient ratios. We tested rosin (colophony) and gum adhesives, containing additives of beeswax and ochre in varying ratios. During both lap shear and impact tests compound rosin adhesives performed better than single component rosin adhesives, and pure acacia gum was the strongest. The large difference in performance between each base adhesive and the significant changes in performance that occur due to relatively small changes in ingredient ratios lend further support to the notion that high levels of skill and knowledge were required to consistently produce the most effective adhesives. PMID:26983080

  11. Multitechnique monitoring of fatigue damage in adhesively bonded composite lap-joints

    NASA Astrophysics Data System (ADS)

    Karpenko, Oleksii; Koricho, Ermias; Khomenko, Anton; Dib, Gerges; Haq, Mahmoodul; Udpa, Lalita

    2015-03-01

    The requirement for reduced structural weight has driven the development of adhesively bonded joints. However, a major issue preventing their full acceptance is the initiation of premature failure in the form of a disbond between adherends, mainly due to fatigue, manufacturing flaws or impact damage. This work presents the integrated approach for in-situ monitoring of degradation of the adhesive bond in the GFRP composite lap-joint using ultrasonic guided waves and dynamic measurements from strategically embedded FBG sensors. Guided waves are actuated with surface mounted piezoelectric elements and mode tuning is used to provide high sensitivity to the degradation of the adhesive layer parameters. Composite lap-joints are subjected to fatigue loading, and data from piezoceramic transducers are collected at regular intervals to evaluate the progression of damage. Results demonstrate that quasi-static loading affects guided wave measurements considerably, but FBG sensors can be used to monitor the applied load levels and residual strains in the adhesive bond. The proposed technique shows promise for determining the post-damage stiffness of adhesively bonded joints.

  12. A finite element and experimental investigation on the fatigue of riveted lap joints in aircraft applications

    NASA Astrophysics Data System (ADS)

    Atre, Amarendra

    Aircraft fuselage skin panels are joined together by rivets. The initiation and propagation of fatigue cracks in aircraft structures at and around the rivet/skin interface is directly related to residual stress field induced during the riveting process and subsequent service loads. Variations in the manufacturing process, such as applied loading and presence of sealant can influence the induced residual stress field. In previous research, the riveting process has been simulated by a 2D axisymmetric force-controlled analysis. The 2D analysis cannot capture the unsymmetrical residual stress state resulting from process variations. Experimental work has also been limited to observing effects of squeeze force on fatigue crack initiation in the riveted lap joint. In this work, a 3D finite element model of the riveting process that incorporates plasticity and contact between the various surfaces is simulated using ABAQUS finite element code to capture the residual stress state at the rivet/skin interface. The finite element model is implemented to observe the effects of interference, sealant and hole quality on the residual stress state using Implicit and Explicit solvers. Effects of subsequent load transfer are also analyzed with the developed model. A set of controlled lap joint fatigue experiments for the different conditions provides validation to the model.

  13. Monitoring of fatigue damage in composite lap-joints using guided waves and FBG sensors

    NASA Astrophysics Data System (ADS)

    Karpenko, Oleksii; Khomenko, Anton; Koricho, Ermias; Haq, Mahmoodul; Udpa, Lalita

    2016-02-01

    Adhesive bonding is being increasingly employed in many applications as it offers possibility of light-weighting and efficient multi-material joining along with reduction in time and cost of manufacturing. However, failure initiation and progression in critical components like joints, specifically in fatigue loading is not well understood, which necessitates reliable NDE and SHM techniques to ensure structural integrity. In this work, concurrent guided wave (GW) and fiber Bragg grating (FBG) sensor measurements were used to monitor fatigue damage in adhesively bonded composite lap-joints. In the present set-up, one FBG sensor was strategically embedded in the adhesive bond-line of a lap-joint, while two other FBGs were bonded on the surface of the adherends. Full spectral responses of FBG sensors were collected and compared at specific intervals of fatigue loading. In parallel, guided waves were actuated and sensed using PZT wafers mounted on the composite adherends. Experimental results demonstrated that time-of-flight (ToF) of the fundamental modes transmitted through the bond-line and spectral response of FBG sensors were sensitive to fatigue loading and damage. Combination of guided wave and FBG measurements provided the desired redundancy and synergy in the data to evaluate the degradation in bond-line properties. Measurements taken in the presence of continuously applied load replicated the in-situ/service conditions. The approach shows promise in understanding the behavior of bonded joints subjected to complex loading.

  14. Weld seam tracking and lap weld penetration monitoring using the optical spectrum of the weld plume

    SciTech Connect

    Mueller, R.E.; Hopkins, J.A.; Semak, V.V.; McCay, M.H.

    1996-12-31

    Joining of dissimilar materials is a long standing problem in manufacturing, with many tricks and special techniques developed to successfully join specific pairs of materials. Often, these special techniques impose stringent requirements on the process such as precise control of process parameters to achieve the desired joint characteristics. Laser welding is one of the techniques which has had some success in welding dissimilar metal alloys, and appears to be a viable process for these materials. Minimal heat input limits differential thermal expansion, and the small weld pool allows precise control of alloy mixing in the fusion zone. Obtaining optimal weld performance requires accurate monitoring and control of absorbed laser power and weld focus position. In order to monitor the laser welding process, the authors have used a small computer controlled optical spectrometer to observe the emission from the weld plume. Absorbed laser power can be related to the temperature of the weld pool surface and the plume above the weld. Focus position relative to the joint can easily be seen by the proportion of elements from each material existing in the plume. This monitor has been used to observe and optimize the performance of butt and lap welds between dissimilar alloys, where each alloy contains at least one element not found in the other alloy. Results will be presented for a copper-steel butt joint and a lap weld between stainless and low alloy steels.

  15. Digital signal processing using lapped transforms with variable parameter windows and orthonormal bases

    NASA Astrophysics Data System (ADS)

    Raduenz, Brian D.

    1992-12-01

    A number of new concepts and tools for the analysis of signals using variable overlapped windows and orthonormal bases are developed and evaluated. Windowing, often employed as a spectral estimation technique, can result in irreparable distortions in the transformed signal. By placing conditions on the window and incorporating it into the orthonormal representation, any signal distortion resulting from the transformation can be eliminated or cancelled in reconstruction. This concept is critical to the theory discussed. As part of this evaluation, a tensor product based general N-point fast Fourier transform algorithm was implemented in the DOD standard language, Ada. The most prevalent criticism of Ada is slow execution time. This code is shown to be comparable in execution time performance to the corresponding FORTRAN code. Also, a new paradigm is presented for solving the finite length data problem associated with filter banks and lapped transforms. This result could have significant importance in many Air Force applications, such as processing images in which the objects of interest are near the borders. Additionally, a limited number of experiments were performed with the coding of speech. The results indicate the lapped transform evaluated has potential as a low bit rate speech coder.

  16. The development of laser-plasma interaction program LAP3D on thousands of processors

    SciTech Connect

    Hu, Xiaoyan Hao, Liang; Liu, Zhanjun; Zheng, Chunyang; Li, Bin Guo, Hong

    2015-08-15

    Modeling laser-plasma interaction (LPI) processes in real-size experiments scale is recognized as a challenging task. For explorering the influence of various instabilities in LPI processes, a three-dimensional laser and plasma code (LAP3D) has been developed, which includes filamentation, stimulated Brillouin backscattering (SBS), stimulated Raman backscattering (SRS), non-local heat transport and plasmas flow computation modules. In this program, a second-order upwind scheme is applied to solve the plasma equations which are represented by an Euler fluid model. Operator splitting method is used for solving the equations of the light wave propagation, where the Fast Fourier translation (FFT) is applied to compute the diffraction operator and the coordinate translations is used to solve the acoustic wave equation. The coupled terms of the different physics processes are computed by the second-order interpolations algorithm. In order to simulate the LPI processes in massively parallel computers well, several parallel techniques are used, such as the coupled parallel algorithm of FFT and fluid numerical computation, the load balance algorithm, and the data transfer algorithm. Now the phenomena of filamentation, SBS and SRS have been studied in low-density plasma successfully with LAP3D. Scalability of the program is demonstrated with a parallel efficiency above 50% on about ten thousand of processors.

  17. Friction Stir Lap Welding of Magnesium Alloy to Steel: A Preliminary Investigation

    SciTech Connect

    Jana, Saumyadeep; Hovanski, Yuri; Grant, Glenn J.

    2010-12-01

    An initial study was made to evaluate the feasibility of joining Magnesium alloy AZ31 sheet to galvanized steel sheet in lap configuration using friction stir welding (FSW). Two different automotive sheet steels were used for comparative evaluation of the dissimilar joining potential; a 0.8mm thick, electro galvanized (EG) mild steel, and a 1.5mm thick hot dipped galvanized (HDG) high-strength, low-alloy steel (HSLA). These steels were joined to 2.33mm thick AZ31B magnesium sheet. A single FSW tool design was used for both dissimilar welds, and process parameters were kept the same. Average peak load for the AZ31-1.5 mm steel weld joint in lap shear mode was found to be 6.3 ± 1.0 kN. For the AZ31-0.8 mm steel weld, joint strength was 5.1 ± 1.5 kN. Microstructural investigation indicates melting of the Zn coating at the interface and subsequent alloying with the Mg sheet resulting in formation of solidified Zn-Mg alloy layer at AZ31/steel interface.

  18. Joining aluminum to titanium alloy by friction stir lap welding with cutting pin

    SciTech Connect

    Wei, Yanni; Li, Jinglong; Xiong, Jiangtao; Huang, Fu; Zhang, Fusheng; Raza, Syed Hamid

    2012-09-15

    Aluminum 1060 and titanium alloy Ti-6Al-4V plates were lap joined by friction stir welding. A cutting pin of rotary burr made of tungsten carbide was employed. The microstructures of the joining interface were observed by scanning electron microscopy. Joint strength was evaluated by a tensile shear test. During the welding process, the surface layer of the titanium plate was cut off by the pin, and intensively mixed with aluminum situated on the titanium plate. The microstructures analysis showed that a visible swirl-like mixed region existed at the interface. In this region, the Al metal, Ti metal and the mixed layer of them were all presented. The ultimate tensile shear strength of joint reached 100% of 1060Al that underwent thermal cycle provided by the shoulder. - Highlights: Black-Right-Pointing-Pointer FSW with cutting pin was successfully employed to form Al/Ti lap joint. Black-Right-Pointing-Pointer Swirl-like structures formed due to mechanical mixing were found at the interface. Black-Right-Pointing-Pointer High-strength joints fractured at Al suffered thermal cycle were produced.

  19. Correlation-based imaging technique for fatigue monitoring of riveted lap-joint structure

    NASA Astrophysics Data System (ADS)

    Quaegebeur, N.; Ostiguy, P. C.; Masson, P.

    2014-05-01

    In the present study, a correlation-based imaging technique called Excitelet is assessed to monitor fatigue crack propagation in a riveted aluminum lap-joint, representative of an aircraft component. For this purpose, a micro-machined piezoceramic array is used to generate guided waves into the structure and measure the reflections induced by potential damage. The method uses a propagation model to correlate measured signals with a bank of signals and imaging is performed using a round-robin procedure (full-matrix capture). This allows taking into account the transducer dynamics and finite dimensions, multi-modal and dispersive characteristics of the guided wave propagation and complex interaction between with damage. Experimental validation has been conducted on an aluminum lap-joint instrumented with a compact linear piezoceramic array of 8 circular elements of 3 mm diameter each. The imaging technique is applied to detect crack propagation after fatigue cycling. Imaging results obtained using A0 mode at 300 and 450 kHz are presented for different crack sizes. It is demonstrated that crack detection and localization can be achieved, while the correlation level indicates the level of reflected energy, and thus damage severity. An accuracy below 5 mm on damage location can be achieved, demonstrating the potential of the correlation-based imaging technique for damage monitoring of complex aerospace structures.

  20. Large-Scale Advanced Prop-Fan (LAP) pitch change actuator and control design report

    NASA Technical Reports Server (NTRS)

    Schwartz, R. A.; Carvalho, P.; Cutler, M. J.

    1986-01-01

    In recent years, considerable attention has been directed toward improving aircraft fuel consumption. Studies have shown that the high inherent efficiency previously demonstrated by low speed turboprop propulsion systems may now be extended to today's higher speed aircraft if advanced high-speed propeller blades having thin airfoils and aerodynamic sweep are utilized. Hamilton Standard has designed a 9-foot diameter single-rotation Large-Scale Advanced Prop-Fan (LAP) which will be tested on a static test stand, in a high speed wind tunnel and on a research aircraft. The major objective of this testing is to establish the structural integrity of large-scale Prop-Fans of advanced construction in addition to the evaluation of aerodynamic performance and aeroacoustic design. This report describes the operation, design features and actual hardware of the (LAP) Prop-Fan pitch control system. The pitch control system which controls blade angle and propeller speed consists of two separate assemblies. The first is the control unit which provides the hydraulic supply, speed governing and feather function for the system. The second unit is the hydro-mechanical pitch change actuator which directly changes blade angle (pitch) as scheduled by the control.