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1

Relationship of the lingual frenum to the mandibular central incisors  

PubMed Central

Clinical implication The purpose of this study is to record the vertical distance between anterior attachment of lingual frenum and incisal edge of mandibular central incisors in dentulous subjects and then determine the mean vertical distance and to suggest guidelines for positioning of mandibular central incisors in complete dentures. Method In this study, 150 dentulous subjects (75 males and 75 females) were chosen based on predecided inclusion criteria. A mandibular cast was obtained from irreversible hydrocolloid impression in modified stock trays for each subject. All subjects were instructed to elevate the tongue while the impressions were made. The vertical distance between the anterior attachment of the lingual frenum and incisal edges of mandibular central incisors was measured on the casts and then the values were statistically analyzed. Result The distance between anterior attachment of lingual frenum (AALF) mesioincisal edge of mandibular central incisor (CI) in male, female and total (male + female) subjects was measured. In males it ranged from 7.3 to 8.9 mm with mean (±SD) 8.29 ± 0.36 mm while in females it ranged from 7.1 to 9.0 mm with mean (±SD) 8.21 ± 0.38 mm. Conclusion It is believed that the application of this anatomic relation can provide a reliable point for arranging and checking the position of the mandibular central incisors for complete dentures in patients with class I ridge relationship.

Gupta, Swati; Garg, Sanchit; Tandan, Amrit; Dwivedi, Ravi; Gupta, Narendra Kumar; Agarwal, Garima

2015-01-01

2

Concomitant solitary median maxillary central incisor and fused right mandibular incisor in primary dentition  

PubMed Central

Solitary median maxillary central incisor (SMMCI) is a unique developmental anomaly in primary dentition. It involves central incisor tooth germs and may or may not be associated with other anomalies. Its presence, concomitant with fusion of right mandibular incisors has not previously been reported. A 5-year-old girl was presented with a single symmetrical primary maxillary incisor at the midline, with the absence of labial frenulum, an indistinct philtrum and a prominent midpalatal ridge. There was an associated fused tooth in the right incisor region and radiographic examination confirmed only one maxillary central incisor in both the dentitions. Family history revealed that the father of the girl also had a similar anomaly providing probable evidence of etiological role for heredity in SMMCI. PMID:23230364

Shilpa, G.; Nuvvula, Sivakumar; Gokhale, Niraj; Yamini, V.

2012-01-01

3

Treatment of an impacted dilacerated maxillary central incisor.  

PubMed

The diagnosis of an impacted incisor with dilaceration refers to a dental deformity characterized by an angulation between the crown and the root, causing noneruption of the incisor. In the past, surgical extraction was the first choice in treating severely dilacerated incisors. The purpose of this case report was to present the correction of a horizontally impacted and dilacerated central incisor through 2-stage crown exposure surgery combined with continuous-force orthodontic traction. The tooth was successfully moved into its proper position. The treatment is discussed, and the orthodontic implications are considered, with a review of the current literature on this topic. PMID:21392694

Pavlidis, Dimitrios; Daratsianos, Nikolaos; Jäger, Andreas

2011-03-01

4

Premolar transplantation to replace a missing central incisor.  

PubMed

During childhood, the anterior maxilla is susceptible to injury, and the loss of incisors is one of the most serious injuries. In many cases, autotransplantation is the best alternative for children who lose an incisor during the growth phase. This case report describes the treatment of a boy who had a traumatic injury when he was 8 years old that resulted in avulsion of the maxillary right central incisor. When he sought treatment at age 10, the space was lost as was bone in the incisor region. Because he lacked space in the mandibular arch for proper tooth alignment, extractions were planned. One extracted premolar was transplanted into the space of the missing maxillary incisor area. The posttreatment results were good, and follow-up records 7 and 9 years after treatment showed healthy periodontal support and cortical bone gain in the transplanted tooth's buccal area. PMID:25726407

Cunha, Deise Lima; Masioli, Marco Antonio; Intra, João Batista Gagno; Roldi, Armelindo; Dardengo, Camila de Sousa; Miguel, Jose Augusto Mendes

2015-03-01

5

Dental transposition of canine and lateral incisor and impacted central incisor treatment: A case report  

PubMed Central

Introduction Dental transposition and impaction are disorders related to ectopic eruption or failure in tooth eruption, which can affect child physical, mental and social development and may be difficult to be clinically solved. Methods We describe a case of transposition between the upper left canine and lateral incisor associated with impaction of the central incisor on the same side, in a 12-year-old patient. Conservative treatment involving surgical-orthodontic correction of transposed teeth and traction of the central incisor was conducted. Conclusion The option of correcting transposition and orthodontic traction by means of the segmented arch technique with devices such as cantilever and TMA rectangular wire loops, although a complex alternative, was proved to be esthetically and functionally effective. PMID:24713567

Gebert, Tarcisio Jacinto; Palma, Vinícius Canavarros; Borges, Alvaro Henrique; Volpato, Luiz Evaristo Ricci

2014-01-01

6

Management of Unerupted Maxillary Deciduous Central Incisor: A Case Report  

PubMed Central

ABSTRACT Failure of eruption of primary teeth can be considered rare, especially in maxillary anterior teeth. The problem can be either mechanical obstruction of eruption or a failure of the eruption mechanism. This case report presents failure of eruption of the maxillary right deciduous central incisor in a 4-year-old girl. The unerupted primary tooth was removed surgically. The histological finding revealed fibroma with reactive giant cells. Periodic follow-up visits were advised to monitor the developing dentition and to ensure enough space for the permanent incisor. How to cite this article: Shakra KA. Management of Unerupted Maxillary Deciduous Central Incisor: A Case Report. Int J Clin Pediatr Dent 2014;7(1):58-60. PMID:25206241

2014-01-01

7

Elastic Band Causing Exfoliation of the Upper Permanent Central Incisors  

PubMed Central

Objective. This study reports a case in which elastic band use culminated in the loss of the incisors. Case Report. An 11-year-old white girl was seen complaining of pain, with purulent discharge and severe tooth mobility. The bone destruction detected radiographically in the region, despite its single location and absence in posterior quadrants of the maxilla and/or mandible, was similar to that observed in Langerhans cell disease. To our surprise, an elastic band involving the midportion of the roots of the two upper central incisors was found during biopsy. The debris was removed and a metal wire was placed in permanent maxillary right and left incisors. The patient was followed up, but no improvement in tooth mobility was observed. Bone loss increased, and internal resorption and root exposure occurred, which culminated in the extraction of permanent maxillary right and left incisors. Conclusion. The present case highlights the fact that professionals sometimes are confronted by anamnestic reports never seen before.

2015-01-01

8

Fragment Reattachment after Atypical Crown Fracture in Maxillary Central Incisor  

PubMed Central

Background. Fracture by trauma is one of the most common types of dental injury in the permanent dentition among children and teenagers. Aim. The aim of this study was to report the treatment performed to an atypical dental trauma case in a maxillary central incisor of a young patient by means of reattachment of the tooth fragment. Case Description. A 12-year-old male patient suffered a vertical crown fracture to the maxillary right central incisor. After clinical and radiographic examinations, a conservative restorative treatment which consisted in the reattachment of the tooth fragment with flow resin was performed in order to preserve the dental element and to obtain maximum aesthetics. Conclusion. The reattachment of fractured fragment is a fast and easy technique that can be used successfully as an option to restore dental element which suffered trauma. Clinical Significance. This technique restores the aesthetics and function of the dental element with minimal discomfort to the patient. PMID:25610663

Vaz, Vanessa Torraca Peraro; Presoto, Cristina Dupim; Jordão, Keren Cristina Fagundes; Paleari, André Gustavo; Dantas, Andrea Abi-Rached; Segalla, José Claudio Martins; de Oliveira Junior, Osmir Batista

2014-01-01

9

Surgical Management of Mandibular Central Incisors with Dumbbell Shaped Periapical Lesion: A Case Report  

PubMed Central

Dental traumatic injuries may affect the teeth and alveolar bone directly or indirectly. Pulpal necrosis and chronic and apical periodontitis with cystic changes are the most common sequelae of the dental traumatic injuries, if the teeth are not treated immediately. This case report focuses on the conventional and surgical management of mandibular central incisors. A twenty-four-year-old male patient presented with pain in the mandibular central incisors. Radiographic examination revealed mandibular central incisors with dumbbell shaped periapical lesion. After root canal treatment, parendodontic surgery was performed for mandibular central incisors. After one-year recall examination, the teeth were asymptomatic and periapical lesion had healed. PMID:25105031

Venigalla, Bhuvan Shome; Patil, Jayaprakash D.; Jayaprakash, Thumu; Chaitanya, C. H. Krishna; Kalluru, Rama S.

2014-01-01

10

Endodontic Management of a Mandibular Central Incisor with Type IV Canal Pattern: A Case Report  

PubMed Central

The success of endodontic treatment requires the knowledge of tooth morphology and its variations. Mandibular incisor’s anatomy presents a challenge when an endodontic access is made, because of its small size and high prevalence of two canals. We are describing a Weine’s Type IV root canal configuration that was detected in a mandibular central incisor, which was demonstrated by a radiographic examination. This article also focuses on the successful endodontic treatment of a mandibular central incisor with a single canal at the pulp chamber, which divided into two distinct and separate canals (buccolingual) at the middle third of the root. PMID:24783153

Mittal, Sunandan; Kumar, Tarun; Sharma, Jyotika; Mittal, Shifali; Ahuja, Tarun

2014-01-01

11

Variation in Size and Form between Left and Right Maxillary Central Incisor Teeth  

PubMed Central

Background: To compare the variation in size of left and right maxillary central incisors for male patients (using digital calipers of 0.01 mm accuracy). To compare the variation in size of left and right maxillary central incisors for female patients (using digital calipers of 0.01 mm accuracy). To find out the difference between the maxillary central incisors of men and women. Its clinical applicability if difference exists. Materials and Methods: A total of 70 dental students of PMNM Dental College and Hospital were selected. Of 70 dental students, 40 male and 30 female were selected. Impressions were made for all subjects, using irreversible hydrocolloid (Algitex, manufacturer DPI, Batch-T-8804) using perforated stock metal trays. The mesiodistal crown width and cervical width were measured for each incisor and recorded separately for left and right teeth. The length was measured for each incisor and recorded separately for left and right maxillary central incisor using digitec height caliper. Results: The mean value of maximum crown length of maxillary left central incisor of male was greater in length compared with maxillary right central incisor. Mean value of maximum crown length for male patient right and left side was greater compared with maximum crown length of female patient. Conclusion: When compared the dimensions of teeth between two sex, male group shows larger values to female group. PMID:25859104

Vadavadagi, Suneel V; Hombesh, M N; Choudhury, Gopal Krishna; Deshpande, Sumith; Anusha, C V; Murthy, D Kiran

2015-01-01

12

Endodontic Management of a Mandibular Central Incisor with Type IV Canal Pattern: A Case Report.  

PubMed

The success of endodontic treatment requires the knowledge of tooth morphology and its variations. Mandibular incisor's anatomy presents a challenge when an endodontic access is made, because of its small size and high prevalence of two canals. We are describing a Weine's Type IV root canal configuration that was detected in a mandibular central incisor, which was demonstrated by a radiographic examination. This article also focuses on the successful endodontic treatment of a mandibular central incisor with a single canal at the pulp chamber, which divided into two distinct and separate canals (buccolingual) at the middle third of the root. PMID:24783153

Mittal, Sunandan; Kumar, Tarun; Sharma, Jyotika; Mittal, Shifali; Ahuja, Tarun

2014-03-01

13

The influence of maxillary central incisor position in complete dentures on \\/s\\/ sound production  

Microsoft Academic Search

Statement of problem. The insertion of prosthodontic restorations often leads to speech defects, most of which are transient but nevertheless a source of concern to the patient. For the dental practitioner, there are few guidelines on designing a prosthetic restoration with maximum phonetic success. Purpose. This study investigated the effect of different maxillary central incisor positions on phonetic patterns. Material

Christoph Runte; Michael Lawerino; Dieter Dirksen; Friedhelm Bollmann; Antoinette Lamprecht-Dinnesen; Eberhard Seifert

2001-01-01

14

Simultaneous Replacement of Maxillary Central Incisors with CEREC Biogeneric Reference Technique: A Case Report  

PubMed Central

Biogeneric Reference Technique (BRT) of the CEREC 3D v.3.8 software is an effective technique for single anterior ceramic crowns because it provides computer-controlled match of the tooth form to the contralateral tooth. BRT also enables the fabrication of two or more anterior all-ceramic crowns simultaneously. This clinical report demonstrates the clinical application of BRT for designing and milling two central incisors in one appointment using a single optical impression. After completing the virtual design of the first central incisor, it was copied and a mirror image was created. The second central incisor was designed using this replicated image and therefore a computer-controlled symmetry was obtained. The crowns were milled from monolithic feldspathic ceramic blocks and adhesively luted with dual-cured resin cement following dentin conditioning. At the two-year follow-up appointment, the restorations were intact, no adverse effects were noted, and the resultant appearance was highly satisfactory for the patient. A step-by-step protocol is described from design to cementation of these restorations. PMID:23875091

Akgungor, Gokhan; Sen, Deniz; Bal, Eray; Özcan, Mutlu

2013-01-01

15

Clinical Management of Mid-Root Fracture in Maxillary Central Incisors: Case Reports  

PubMed Central

Management of mid-root fractures presents a formidable challenge for clinicians because of the difficulty of achieving a stable reunion of fracture fragments. This article presents two varied treatment options for mid-root fractures. A 15-year-old female reported an impact injury to the maxillary anterior teeth 2 days after its occurrence. Clinically, the maxillary left central incisor was palatally-extruded with a negative vitality response and radiographic evidence of an oblique fracture at the middle third of the root. An endodontic implant was employed which utilized an open technique and has been on follow-up for ten months. A 32-year-old male reported an injury, which resulted in a mobile maxillary right central incisor, three months after its occurrence. Through clinical and radiographic means, a discolored, extruded, and non-vital maxillary right central incisor with an oblique root fracture at the alveolar-crest level was observed. Exploratory surgery was performed; an apical barrier was created with a mineral trioxide aggregate and obturated with gutta percha. The fragments were stabilized with a fiber post and patient has been on follow-up for five months. Short-term follow-up for both of the cases showed promising results both clinically and radiographically. PMID:21404971

Parekh, Deepak J; Sathyanarayanan, Ramarao; Manjunath, Mangala Tiptur

2010-01-01

16

Contour changes in human alveolar bone following tooth extraction of the maxillary central incisor  

PubMed Central

The purpose of this study was to apply cone-beam computed tomography (CBCT) to observe contour changes in human alveolar bone after tooth extraction of the maxillary central incisor and to provide original morphological evidence for aesthetic implant treatment in the maxillary anterior area. Forty patients were recruited into the study. Each patient had two CBCT scans (CBCT I and CBCT II), one taken before and one taken three months after tooth extraction of maxillary central incisor (test tooth T). A fixed anatomic reference point was used to orient the starting axial slice of the two scans. On three CBCT I axial slices, which represented the deep, middle, and shallow layers of the socket, labial and palatal alveolar bone widths of T were measured. The number of sagittal slices from the start point to the pulp centre of T was recorded. On three CBCT II axial slices, the pulp centres of extracted T were oriented according to the number of moved sagittal slices recorded in CBCT I. Labial and palatal alveolar bone widths at the oriented sites were measured. On the CBCT I axial slice which represented the middle layer of the socket, sagittal slices were reconstructed. Relevant distances of T on the sagittal slice were measured, as were the alveolar bone width and tooth length of the opposite central incisor. On the CBCT II axial slice, which represented the middle layer of the socket, relevant distances recorded in CBCT I were transferred on the sagittal slice. The height reduction of alveolar bone on labial and palatal sides was measured, as were the alveolar bone width and tooth length of the opposite central incisor at the oriented site. Intraobserver reliability assessed by intraclass correlation coefficients (ICCs) was high. Paired sample t-tests were performed. The alveolar bone width and tooth length of the opposite central incisor showed no statistical differences (P<0.05). The labial alveolar bone widths of T at the deep, middle, and shallow layers all showed statistical differences. However, no palatal alveolar bone widths showed any statistical differences. The width reduction of alveolar bone was 1.2, 1.6, and 2.7 mm at the deep, middle, and shallow layers, respectively. The height reduction of alveolar bone on labial and palatal sides of T both showed statistical differences, which was 1.9 and 1.1 mm, respectively. PMID:25471836

Li, Bei; Wang, Yao

2014-01-01

17

Contour changes in human alveolar bone following tooth extraction of the maxillary central incisor.  

PubMed

The purpose of this study was to apply cone-beam computed tomography (CBCT) to observe contour changes in human alveolar bone after tooth extraction of the maxillary central incisor and to provide original morphological evidence for aesthetic implant treatment in the maxillary anterior area. Forty patients were recruited into the study. Each patient had two CBCT scans (CBCT I and CBCT II), one taken before and one taken three months after tooth extraction of maxillary central incisor (test tooth T). A fixed anatomic reference point was used to orient the starting axial slice of the two scans. On three CBCT I axial slices, which represented the deep, middle, and shallow layers of the socket, labial and palatal alveolar bone widths of T were measured. The number of sagittal slices from the start point to the pulp centre of T was recorded. On three CBCT II axial slices, the pulp centres of extracted T were oriented according to the number of moved sagittal slices recorded in CBCT I. Labial and palatal alveolar bone widths at the oriented sites were measured. On the CBCT I axial slice which represented the middle layer of the socket, sagittal slices were reconstructed. Relevant distances of T on the sagittal slice were measured, as were the alveolar bone width and tooth length of the opposite central incisor. On the CBCT II axial slice, which represented the middle layer of the socket, relevant distances recorded in CBCT I were transferred on the sagittal slice. The height reduction of alveolar bone on labial and palatal sides was measured, as were the alveolar bone width and tooth length of the opposite central incisor at the oriented site. Intraobserver reliability assessed by intraclass correlation coefficients (ICCs) was high. Paired sample t-tests were performed. The alveolar bone width and tooth length of the opposite central incisor showed no statistical differences (P<0.05). The labial alveolar bone widths of T at the deep, middle, and shallow layers all showed statistical differences. However, no palatal alveolar bone widths showed any statistical differences. The width reduction of alveolar bone was 1.2, 1.6, and 2.7 mm at the deep, middle, and shallow layers, respectively. The height reduction of alveolar bone on labial and palatal sides of T both showed statistical differences, which was 1.9 and 1.1 mm, respectively. PMID:25471836

Li, Bei; Wang, Yao

2014-12-01

18

Aesthetic Value of the Relationship between the Shapes of the Face and Permanent Upper Central Incisor  

PubMed Central

The relationship between the shapes of face and teeth has been analyzed for esthetic purposes and exploited commercially. The methodology to assess this correlation, described in the literature, does not enable reliable application of the concepts. Digital photos of face and incisors of 100 youths were measured with the software Image Tool 3.0 and classified as to shape. The same photographs were also analyzed and classified by a visual criterion. Statistical analysis of the metrical classification was performed by Pearson's correlation coefficient. The Kappa test was used to determine the coefficient of agreement between the observers and the obtained data, and to assess the agreement between both classifications (metrical and visual). The classificatory analysis made by the observers indicated a marked level of disagreement, also identified between their classification and that obtained by metrical analysis. The results indicated no relationship between the shapes of the face and the central incisor. PMID:20871810

de Oliveira Farias, Felipe; Ennes, Jussara P.; Zorzatto, José Roberto

2010-01-01

19

Stress Analysis of a Maxillary Central Incisor Restored with Different Posts  

PubMed Central

Objectives To evaluate the effects of different post materials on the stress distribution in an endodontically treated maxillary incisor. Materials and Methods A pseudo 3-dimensional finite element model was created in a labiolingual cross-sectional view of a maxillary central incisor and modified according to five posts with different physical properties consisting stainless steel, titanium, gold alloy, glass fiber (Snowpost), and carbon fiber (Composipost). A 200 N force was then applied from two different directions; a) vertical load on the incisal edge, b) 45 degree diagonal load above the cingulum location. Stress distribution and values were then calculated by considering the pseudo three dimensional von Mises stress criteria. Results Under two loading conditions, post made of steel showed greatest stress concentration at the post/dentin interface followed by titanium, gold alloy, Snowpost and Composipost. However, Composipost, which elastic modulus was closer to the dentin, produced highest stress values at 1/3 cervical area. Conclusions Within the limitation of this simulated mechanical analysis, we can conclude that the physical characteristics of posts were important on stress distributions in post and core applications. Glass fiber post revealed more balanced stress distribution under functional forces. PMID:19212479

Adanir, Necdet; Belli, Sema

2007-01-01

20

Three-dimensional finite element analysis of the maxillary central incisor in two different situations of traumatic impact  

Microsoft Academic Search

Dental trauma is one of the most common events in dental practice. However, few studies have investigated the biomechanical characteristics of these injuries. The objective of this study was to analyse the stress distribution in the dentoalveolar structures of a maxillary central incisor subjected to two situations of impact loading. The following loading forces were applied using a 3D finite

B. R. da Silva; J. J. S. Moreira Neto; F. I. da Silva Jr; A. S. W. de Aguiar

2011-01-01

21

Torquing an upper central incisor with aligners--acting forces and biomechanical principles.  

PubMed

The forces delivered by aligners during torquing have still not been investigated. The purpose of this study was to measure the forces delivered to an upper central incisor during torquing with three different materials of the same thickness, and to describe the biomechanical principles of torquing with aligners. Five identical appliances were manufactured from each of three materials, all with a thickness of 1.0 mm (Ideal Clear®, Erkodur®, and Biolon®). An upper central incisor, as part of the measuring device, was torqued in defined steps in the vestibular and palatal directions with the respective appliance in place. For statistical analysis, the resulting forces, Fx (forces acting in the palatal and facial directions) and Fz (intrusive force as a side-effect) at a displacement of ±0.15 and ±0.8 mm from the tooth at the gingival margin were calculated. The mean Fx forces for ±0.15 mm displacement ranged from -1.89 N [standard deviation (SD) 0.48] to 0.11 N (SD 0.1). The mean Fz forces were between -0.97 N (SD 0.57) and -0.07 N (SD 0.22). The highest intrusive forces were measured during palatal displacement of the measuring tooth. An influence of direction of displacement on the levels of force was observed, especially for Fz at the greater displacement of ±0.8 mm. In relation to the intended amount of root movement during torquing, aligners tend to 'lift up' and therefore no effective force couple can be established for further root control. The force delivery properties are also influenced by the material used and the shape of the tooth. PMID:20462912

Hahn, Wolfram; Zapf, Antonia; Dathe, Henning; Fialka-Fricke, Julia; Fricke-Zech, Susanne; Gruber, Rudolf; Kubein-Meesenburg, Dietmar; Sadat-Khonsari, Reza

2010-12-01

22

Initial forces generated by three types of thermoplastic appliances on an upper central incisor during tipping.  

PubMed

The force properties of thermoformed appliances have not been systematically investigated. Therefore, the aim of the present study was to quantify the forces delivered by thermoplastic appliances manufactured from three different materials, with the same thickness, on a central upper incisor, during tipping. Five identical appliances were manufactured from three different materials all with a thickness of 1.0 mm (Ideal Clear, Erkodur, and Biolon). For measuring the forces, an isolated measuring tooth, as part of a standardized resin model incorporated in a newly developed measuring device, was tipped in nine 2.7 arc minute (0.04629 degree) steps, from 0 to 0.416 degrees in the vestibular and palatal directions around a rotational axis through the virtual apex, after positioning an appliance on the model. For statistical analysis, the force components Fx/tipping and Fz/intrusion at a displacement of +/-0.151 mm from the incisor edge were determined. Means and standard deviations (SDs) were calculated. The Kruskal-Wallis test for overall effects and the Wilcoxon two-sample test for individual group pairings were used (P < 0.05 significance level). The mean Fx forces ranged from -2.82 N (SD 0.62) to 5.42 N (SD 0.56). The mean Fz forces were between -0.14 N (SD 0.52) and -2.3 N (SD 0.43). The highest intrusive forces were measured during vestibular displacement of the measuring tooth. The forces delivered by the Biolon appliance were found to be much greater (P < 0.01) than those of the other materials. The forces delivered by the materials investigated were mostly higher than those stated in the literature. PMID:19525441

Hahn, Wolfram; Fialka-Fricke, Julia; Dathe, Henning; Fricke-Zech, Susanne; Zapf, Antonia; Gruber, Rudolf; Kubein-Meesenburg, Dietmar; Sadat-Khonsari, Reza

2009-12-01

23

Nasopalatine canal position relative to the maxillary central incisors: a cone beam computed tomography assessment.  

PubMed

The aim of this study was to determine the proximity of the nasopalatine canal (NPC) to the maxillary central incisor root (MCIR). The study included 120 cone beam computed tomography scans obtained from the Center for Implant Dentistry, Loma Linda University, between June 2006 and September 2009. They were equally distributed into six groups: (1) 21- to 40-year-old men, (2) 21- to 40-year-old women, (3) 41- to 60-year-old men, (4) 41- to 60-year-old women, (5) 61- to 80-year-old men, and (6) 61- to 80-year-old women. The closest distances between the NPC and the MCIR (NPC-to-MCIR) were measured at the midroot (bisecting palatal cementoenamel junction to root apex) and the apex levels. Differences between the groups were analyzed using a t test and 1-way analysis of variance at a significance level of ? = .05. The overall mean NPC-to-MCIR distances at the midroot and apex levels were 3.05 ± 1.64 and 5.22 ± 1.56 mm, respectively. The modes of the NPC-to-MCIR distances at the midroot and apex levels were in the range of 1.01-2.00 mm and 4.01-5.00 mm, respectively. The mean NPC-to-MCIR distance was significantly greater in men than in women at the midroot level (P < .05) but not at the apex level (P > .05). The mean NPC-to-MCIR distance was significantly shorter for the youngest age group than the other two age groups at the midroot level (P < .05). However, at the apex level, the youngest age group had a significantly shorter distance compared with the oldest age group (P < .05) but not the middle age group (P > .05). The results of this study suggest that, to avoid NPC penetration, more care must be exercised during immediate implant placement at the midroot level of a maxillary central incisor in women and younger patients because of the root proximity to the NPC. Tapered implants may also be beneficial in such situations. PMID:20932126

Chatriyanuyoke, Pakawat; Lu, Chun-I; Suzuki, Yusuke; Lozada, Jaime L; Rungcharassaeng, Kitichai; Kan, Joseph Y K; Goodacre, Charles J

2012-12-01

24

Study of the morpho-dimensional relationship between the maxillary central incisors and the face.  

PubMed

The aim of this study was to evaluate the frequency of agreement between the shape of the maxillary central incisor (MCI) and that of the face; verify which is the most pleasing MCI shape for the two genders; whether there is coincidence in the preference for tooth shape; and measure the most pleasant proportion of tooth and facial width for the esthetics of the smile. One hundred patients were selected from among front view photographs of the face and smile. The photographs were evaluated to determine the shape of the face and the type of dental contour, the pleasant appearance of the set consisting of the teeth and facial features. The widths of the MCIs and the face were measured and the proportional values were associated with the evaluators' opinions with regard to the pleasant appearance of the set of facial features. There was a significant association between the shape of the face and the MCI (Bowker's test, p = 0.0015). There is a relationship between the shape of the MCI and the shape of the face, with a greater prevalence of the oval shape of the teeth and face; it was not possible to associate the pleasant appearance of the shape of teeth with gender; there was no agreement on the pleasant appearance of the shape of teeth in the photographs of the patient smiling and in the images of the smile; and there was no relationship between the pleasant appearance of the face and the dentofacial proportion and bizygomatic width. PMID:21503417

Pedrosa, Vivianne Oliveira; França, Fabiana Mantovani Gomes; Flório, Flávia Martão; Basting, Roberta Tarkany

2011-01-01

25

Management of synodontia between dilacerated permanent maxillary central incisor and supernumerary tooth with aid of cone-beam computed tomography  

PubMed Central

A malformed tooth characterized by one or more developmental disturbances is often difficult to treat. When such teeth are present in anterior region, they pose a technical challenge for the clinician to restore esthetics as well as function. This case describes endodontic, surgical, and restorative management of fused and dilacerated maxillary central incisor. Cone-beam computed tomography (CBCT) was used in the present case to aid in understanding of complicated tooth morphology and managing the case successfully.

Das, Suroopa; Warhadpande, Manjusha M.; Redij, Saurabh Anil; Sabir, Husain; Shirude, Tushar

2015-01-01

26

Management of synodontia between dilacerated permanent maxillary central incisor and supernumerary tooth with aid of cone-beam computed tomography.  

PubMed

A malformed tooth characterized by one or more developmental disturbances is often difficult to treat. When such teeth are present in anterior region, they pose a technical challenge for the clinician to restore esthetics as well as function. This case describes endodontic, surgical, and restorative management of fused and dilacerated maxillary central incisor. Cone-beam computed tomography (CBCT) was used in the present case to aid in understanding of complicated tooth morphology and managing the case successfully. PMID:25829699

Das, Suroopa; Warhadpande, Manjusha M; Redij, Saurabh Anil; Sabir, Husain; Shirude, Tushar

2015-01-01

27

Glossectomy as an adjunct to correct an open-bite malocclusion with shortened maxillary central incisor roots.  

PubMed

A young man, 19 years of age, with the chief complaint of an anterior open bite, came for orthodontic treatment with a skeletal Class I relationship, anterior open bite, shortened maxillary incisor roots, and relative macroglossia. The malocclusion was treated by extracting the maxillary first premolars and using a fixed edgewise appliance. A partial glossectomy was performed before the orthognathic surgery with a 3-piece segmental LeFort I mandibular setback, and advancement was achieved with a reduction genioplasty. A functional and esthetic occlusion with an improved facial profile was established, and the apex of the maxillary left central incisor became slightly rounded after prolonged and significant tooth movement. Four years after treatment, there was occlusal stability of the results, and no further root shortening was observed. PMID:23810054

Tanaka, Orlando Motohiro; Guariza-Filho, Odilon; Carlini, João Luiz; Oliveira, Dauro Douglas; Pithon, Matheus Mello; Camargo, Elisa Souza

2013-07-01

28

Treatment of maxillary central incisor with external root resorption using mineral trioxide aggregate: 18 months follow-up.  

PubMed

External cervical resorption is the loss of dental hard tissue as a result of odontoclastic action; it usually begins on the cervical region of the root surface of the teeth. This case report demonstrates an external cervical resorption in a maxillary central incisor of a 24-year-old male patient. After surgical intervention and root canal treatment, the resorption was subsequently sealed with mineral trioxide aggregate. The 18 months follow-up demonstrates no pathological changes on clinical and radiographic examination. This case report presents a treatment strategy that might improve the healing outcomes for patients with external cervical resorption. PMID:23843419

Gandi, Padma; Disha, Saraswathi

2013-01-01

29

Fracture resistance of endodontically treated maxillary central incisors with varying ferrule heights and configurations: In vitro study  

PubMed Central

Objective: The objective of this study is to determine the best ferrule configuration of endodontically treated teeth. Materials and Methods: A total of 40 freshly extracted maxillary central incisors were collected. Teeth were allocated into following four groups of each having 10 teeth. Group 1 teeth restored with crowns (CRN), Group 2 endodontically treated teeth restored with crowns (RCT and CRN), Group 3 endodontically treated teeth restored with cast dowel cores and crowns incorporating uniform 2 mm ferrule (2 FRL), Group 4 endodontically treated teeth restored with cast dowel cores and crowns incorporating uniform 1 mm ferrule (1 FRL). Crown preparation was performed with varying ferrule heights, crowns were cemented with resin modified glass ionomer cement and were kept in 100% humidity for 3 days, all specimens were loaded to failure in a universal testing machine at 0.5 mm/min. Results were obtained in the form of kilo Newton and Newton. Result: The statistical analysis applied was an analysis of variance to detect the presence of group differences. Pair wise comparisons between the groups were analyzed with the Tukey Kramer significant difference test for multiple comparisons. Conclusion: Ferrule had a significant role in the fracture resistance of custom cast post core restored teeth. Endodontically treated maxillary central incisors with a uniform 2 mm ferrule were more fracture resistant than those with a uniform 1 mm ferrule. PMID:24778504

Singh, Smita; Thareja, Prerna

2014-01-01

30

INFLUENCE OF PROTAPER FINISHING FILES AND SODIUM HYPOCHLORITE ON CLEANING AND SHAPING OF MANDIBULAR CENTRAL INCISORS – A HISTOLOGICAL ANALYSIS  

PubMed Central

Objective: This study investigated the influence of the last apical instrument of the ProTaper system with and without 2.5% sodium hypochlorite for cleaning mandibular central incisors. Material and Methods: Thirty two mandibular central incisors were divided into six study groups: Group I – F1 instrument with 2.5% sodium hypochlorite; Group II – F1 and F2 with 2.5% sodium hypochlorite; Group III – F1, F2 and F3 with 2.5% sodium hypochlorite; Group IV – F1 with distilled water; Group V – F1 and F2 with distilled water; Group VI – F1, F2 and F3 with distilled water. The two remaining teeth comprised the negative control group. The specimens were prepared following the principles of the technique suggested by the manufacturer and then submitted to histological preparation and morphometric analysis. Data were analyzed statistically by the Kruskal Wallis test at 1% significance level. Results: There was statistically significant difference (p<0.01) between all study groups, except between Groups I and VI. Conclusions: It was concluded that no technique allowed complete cleaning of the root canals. However, the technique of finishing preparation of the apical third with the F3 instrument with 2.5% sodium hypochlorite irrigation was the most effective. PMID:19466257

Baratto, Flares; Leonardi, Denise Piotto; Zielak, João César; Vanni, José Roberto; Sayão-Maia, Sandra Maria Alves; Sousa, Manoel D.

2009-01-01

31

Prosthetic rehabilitation and management of an MTA-treated maxillary central incisor with root perforation and severe internal resorption.  

PubMed

Root canal perforation and root resorption are challenging clinical conditions to correctly diagnose and treat, especially when they occur in anterior teeth. This clinical report describes the computed tomography findings, endodontic treatment, prosthetic rehabilitation, and clinical outcome of an iatrogenic root perforation and internal resorption in a maxillary central incisor. The case management consisted of endodontic retreatment, periodontal surgery, and prosthetic rehabilitation. Gray mineral trioxide aggregate (MTA) was used to fill the resorption space and seal the perforation. The prosthetic treatment was performed with glass fiber-reinforced dowels and all-ceramic crowns. No signs or symptoms, including discomfort, pain, or esthetic defects were observed in 30 months of follow-up. PMID:23387526

Abuabara, Allan; Costa, Rogério G; Morais, Eduardo C; Furuse, Adilson Y; Gonzaga, Carla C; Filho, Flares Baratto

2013-07-01

32

Three-dimensional finite element analysis of the maxillary central incisor in two different situations of traumatic impact.  

PubMed

Dental trauma is one of the most common events in dental practice. However, few studies have investigated the biomechanical characteristics of these injuries. The objective of this study was to analyse the stress distribution in the dentoalveolar structures of a maxillary central incisor subjected to two situations of impact loading. The following loading forces were applied using a 3D finite element model: a force of 2000 N acting at an angle of 90°on the buccal surface of the crown and a vertical 2000 N force acting in the cleidocranial direction on the incisal surface of the tooth. Harmful stresses were observed in both situations, causing damage to both the tooth and adjacent tissue. However, the damage found in soft tissues such as periodontal ligament and dental pulp was negligible. In conclusion, injuries resulting from the traumatic situations were more damaging to the integrity of the tooth and its associated hard-tissue structures. PMID:21895556

da Silva, B R; Moreira Neto, J J S; da Silva, F I; de Aguiar, A S W

2013-01-01

33

Orthodontic movement of a maxillary central incisor with a horizontal root fracture treated using an intra-radicular fibre splint.  

PubMed

This paper reports the case of a 15-year-old boy with a horizontal root fracture in the left maxillary central incisor along with class II division 1 malocclusion for whom a fixed orthodontic treatment was planned. The fracture was present at the junction of apical and middle-third as a result of trauma 2 years back. No splinting was carried out at that time and the tooth was found to be vital, asymptomatic and showed a type-1 repair pattern. An intentional root canal treatment was carried out for placement of an intra-radicular fiber splint, nearly 3 mm beyond the fracture line. Orthodontic treatment was initiated after a month; to which the fractured and splinted tooth responded successfully. This report highlights the successful use of an intra-radicular splint for horizontally fractured tooth requiring orthodontic treatment. PMID:24015026

Kapur, Aditi; Utreja, A; Goyal, A; Pankaj, P

2013-04-01

34

Incisor crown bending strength correlates with diet and incisor curvature in anthropoid primates.  

PubMed

Anthropoid incisors are large relative to the postcanine dentition and function in the preprocessing of food items. Previous analyses of anthropoid incisor allometry and shape demonstrate that incisor morphology is correlated with preferred foods and that more frugivorous anthropoids have larger and more curved incisors. Although the relationship between incisal crown curvature and preferred foods has been well documented in extant and fossil anthropoids, the functional significance of curvature variation has yet to be conclusively established. Given that an increase in crown curvature will increase maximum linear crown dimensions, and bending resistance is a function of linear crown dimensions, it is hypothesized that incisor crown curvature functons to increase incisor crown resistance to bending forces. This study uses beam theory to calculate the mesiodistal and labiolingual bending strengths of the maxillary and mandibular incisors of hominoid and platyrrhine taxa with differing diets and variable degrees of incisal curvature. Results indicate that bending strength correlates with incisal curvature and that frugivores have elevated incisor bending resistance relative to folivores. Maxillary central incisor bending strengths further discriminate platyrrhine and hominoid hard- and soft-object frugivores suggesting this crown is subjected to elevated occlusal loading relative to other incisors. These results are consistent with the hypothesis that incisor crown curvature functions to increase incisor crown resistance to bending forces but does not preclude the possibility that incisor bending strength is a composite function of multiple dentognathic variables including, but not limited to, incisor crown curvature. PMID:25156755

Deane, Andrew S

2015-02-01

35

Unusual Transalveolar and Transmuco-Gingival Root Avulsion of a Fractured Primary Central Incisor: A Case with an 8-Year Follow-Up  

PubMed Central

The purpose of this unique case report is to describe a very unusual dentoalveolar fracture associated with avulsion of the near-complete root. A 3-year-old male patient came for consultation after a dentoalveolar trauma with a “fragment that looks like canine” found in his mouth by his mother. This boy suffered root fracture of the upper primary central right incisor, accompanied by transalveolar and transmuco-gingival avulsion of the tooth root fragment, leaving the crown in its position in the dental arch. Clinical and radiological examinations were performed in order to follow up the case: 15 days, one month, and three months after trauma, the crown had a slight mobility without other clinical or radiological signs. After six months, the upper primary central right incisor's crown was exfoliated. Open bite due to the persistence of the pacifier habit favored the crown retention in the mouth. This case emphasizes the importance of primary diagnosis and follow-up of trauma cases. To the best of our knowledge, this kind of dental injury has not been previously described in the literature nor in the current Dental Trauma guidelines for the management of traumatic dental injuries in the primary dentition.

Ferrés-Amat, E.; Díaz-Martínez, C.; Herrera-Martínez, S.; Maura-Solivellas, I.; Ferrés-Padró, E.

2015-01-01

36

Histomorphometric analysis of inflammatory response and necrosis in re-implanted central incisor of rats treated with low-level laser therapy.  

PubMed

Low-level laser therapy is a tool employed in the management of post-operative inflammation process and in the enhancement of reparative process. The aim of the study was to perform histological evaluation of dental and periodontal ligament of rats central upper-left incisor teeth re-implanted and irradiated with low-level laser (InGaAl, 685 nm, 50 J/cm(2)) 15, 30, and 60 days after re-implantation. Seventy-two male rats had the central upper left incisor removed and kept for 15 min on dry gauze before replantation. Laser was irradiated over the root surface and empty alveolus prior replantation and over surrounding mucosa after the re-implantation. After histological procedures, all slices were analyzed regarding external resorption area and histological aspects. We observed an increase of root resorption (p?

Vilela, Rianne Gomes; Gjerde, Kjersti; Frigo, Lucio; Leal Junior, Ernesto Cesar Pinto; Lopes-Martins, Rodrigo Alvaro Brandão; Kleine, Brígida Mônica; Prokopowitsch, Igor

2012-05-01

37

[Incisors with a mind of their own].  

PubMed

A 43-year-old man, known to have hypodontia, was bothered by his over-erupted central incisors. After the placement of implants and the accompanying crown- and bridgework, the central incisors appear to be increasingly over-erupted. The history shows that this phenomenon has already been seen in the past. Three mechanisms can be responsible for the over-eruption, specifically: continuous facial growth, over-eruption of both central incisors in the maxilla as a consequence of agenesis of opposing dentition and relapse of the orthodontic treatment as a result of the fact that orthodontic retention is not readily possible. After the central incisors were first cut in such a way that an acceptable incisal line has again been formed, the single-unit fixed dental prostheses on the front elements were replaced with porcelain ones. PMID:25174187

van Heumen, C M; Termeer, D; Oosterkamp, B C M; Meijer, G J

2014-01-01

38

Endodontic and Esthetic Management of a Dilacerated Maxillary Central Incisor Having Two Root Canals Using Cone Beam Computed Tomography as a Diagnostic Aid  

PubMed Central

Traumatic injuries to the primary dentition are quite common. When primary teeth are subjected to trauma, force transmission and/or invasion of the underlying tooth germs lying in close proximity can result in a variety of disturbances in the permanent successors. Few of these disturbances include hypoplasia, dilaceration, or alteration in the eruption sequence and pattern. Dilaceration is defined as an angulation or sharp bend or curve in the linear relationship of the crown of a tooth to its root. A rare case of maxillary left central incisor having crown dilaceration and Vertucci's type II canal configuration with symptomatic periapical periodontitis is reported. Cone beam computed tomography was used for better understanding of the anomaly and complicated root canal morphology. The tooth was successfully managed by nonsurgical root canal therapy and restoration with resin composite to restore esthetics. PMID:24955260

Sharma, Sarang; Grover, Shibani; Sharma, Vivek; Srivastava, Dhirendra; Mittal, Meenu

2014-01-01

39

Orthodontic treatment of an ankylosed maxillary central incisor through single-tooth osteotomy by using interdental space regained from microimplant anchorage.  

PubMed

This case report describes the treatment of a boy, aged 13.6 years, whose ankylosed maxillary left central incisor had been avulsed and replanted 2.5 years earlier. Ankylosis of the tooth and adjacent alveolar process led to the development of infraocclusion, migration of adjacent teeth, midline deviation, and a vertical alveolar bone defect. Initially, distal tooth movement in the maxillary arch was performed with microimplant anchorage to gain space for repositioning the ankylosed tooth. Then a single-tooth osteotomy was performed in 1 surgical stage to allow for inferior repositioning of the tooth and bone. The ankylosed tooth was successfully leveled in the maxillary arch with a harmonic gingival margin. The total treatment period was 18 months, and the results were acceptable at 14 months after debonding. PMID:22284297

Chae, Jong-Moon; Paeng, Jun-Young

2012-02-01

40

Efficacy of the Lateral Advanced Flap in Root-coverage Procedures for Mandibular Central Incisors: A 5-Year Clinical Study.  

PubMed

The aim of this study was to determine the efficacy of the lateral advanced flap in root-coverage procedures for mandibular incisors and to evaluate pain after treatment. A total of 15 patients who required treatment for gingival recessions were selected from the University of Genoa Laser and Restorative Dentistry Department. The inclusion criteria were the presence of at least one 3-mm gingival recession defect of a mandibular incisor and 3 mm or more of keratinized tissue width on the immediately adjacent tooth. One calibrated masked examiner performed the clinical measurements, including recession depth and width, probing depth, clinical attachment level, and keratinized tissue width. Patients were checked 7, 14, and 30 days after surgery and were included in supportive periodontal maintenance every 4 months. Further follow-ups were done at the first, third, and fifth year postsurgery when the same baseline assessment parameters were recorded according to the root-coverage esthetic score (RES). Numeric score recorded pain evaluations showed a mean of 3 at the day of the surgery, 2 in the first day after the surgery, and no significant scores were referred in the following days. Mean recession depth was 3.2 ± 1.3 mm at baseline; at 5 years, RES showed a positive increase of all scores. The laterally coronally advanced surgical technique was very effective in treating isolated gingival recessions. It combined the esthetic and root-coverage advantages of the coronally advanced flap with the increased gingival thickness and keratinized tissue associated with the lateral gingival flap. PMID:25734716

De Angelis, Nicola; Yumang, Catherine; Benedicenti, Stefano

2015-01-01

41

Radiographic Investigation of Location and Angulation of Curvatures in Human Maxillary Incisors  

Microsoft Academic Search

The aim of this radiographic study was to evaluate the degree and location of root canal curvatures of human maxillary incisors. A total of 286 extracted human maxillary incisors (145 central and 141 lateral incisors) were included in this investigation. Exclusion criteria were teeth with extensive carious lesions, restorations, and root canal treatment. For this in vitro study, the teeth

Brita Willershausen; Adrian Kasaj; Haki Tekyatan; Bernd Roehrig; Benjamin Briseno

2008-01-01

42

Gingival biotype in relation to incisors’ inclination and position  

PubMed Central

Objectives: To study the association between gingival biotypes and inclination and position of the maxillary and mandibular incisors. Methods: This cross-sectional study included 142 consecutive orthodontic patients (64 males and 78 females) who were seeking orthodontic treatment at the Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia from February 2013 to January 2014. Gingival biotype was assessed independently for the maxillary and mandibular central incisors using the transparency of periodontal probe method. Maxillary and mandibular incisors’ inclination and position were measured using cephalometric analysis. Results: The mean age was 23.56 (±2.55) years. The prevalence of thin gingival biotype was 43% for the maxillary and 52.1% for the mandibular incisors. Females were 4 times more likely to have thin gingiva for the maxillary incisors and 5 times more likely for the mandibular incisors. A significant association was found between mandibular incisor inclination and position and thin gingival biotype, while there was no association between the maxillary incisor inclination and position and gingival biotypes. Conclusion: Mandibular incisor proclination and protrusion is associated with thin gingival biotype while no association is found in the maxilla. The evaluation of the gingival biotype is essential during diagnosis and treatment planning for potential orthodontic patients. PMID:25399216

Zawawi, Khalid H.; Al-Zahrani, Mohammad S.

2014-01-01

43

Molar Incisor Hypomineralization, Prevalence, and Etiology  

PubMed Central

Aim. To evaluate the prevalence and possible etiological factors associated with molar incisor hypomineralization (MIH) among a group of children in Jeddah, Saudi Arabia. Methods. A group of 8-12-year-old children were recruited (n = 267) from the Pediatric Dental Clinics at the Faculty of Dentistry, King Abdulaziz University. Children had at least one first permanent molar (FPM), erupted or partially erupted. Demographic information, children's medical history, and pregnancy-related data were obtained. The crowns of the FPM and permanent incisors were examined for demarcated opacities, posteruptive breakdown (PEB), atypical restorations, and extracted FPMs. Children were considered to have MIH if one or more FPM with or without involvement of incisors met the diagnostic criteria. Results. MIH showed a prevalence of 8.6%. Demarcated opacities were the most common form. Maxillary central incisors were more affected than mandibular (P = 0.01). The condition was more prevalent in children with history of illnesses during the first four years of life including tonsillitis (P = 0.001), adenoiditis (P = 0.001), asthma (P = 0.001), fever (P = 0.014), and antibiotics intake (P = 0.001). Conclusions. The prevalence of MIH is significantly associated with childhood illnesses during the first four years of life including asthma, adenoid infections, tonsillitis, fever, and antibiotics intake. PMID:24949012

Allazzam, Sulaiman Mohammed; Alaki, Sumer Madani; El Meligy, Omar Abdel Sadek

2014-01-01

44

Molar incisor hypomineralization, prevalence, and etiology.  

PubMed

Aim. To evaluate the prevalence and possible etiological factors associated with molar incisor hypomineralization (MIH) among a group of children in Jeddah, Saudi Arabia. Methods. A group of 8-12-year-old children were recruited (n = 267) from the Pediatric Dental Clinics at the Faculty of Dentistry, King Abdulaziz University. Children had at least one first permanent molar (FPM), erupted or partially erupted. Demographic information, children's medical history, and pregnancy-related data were obtained. The crowns of the FPM and permanent incisors were examined for demarcated opacities, posteruptive breakdown (PEB), atypical restorations, and extracted FPMs. Children were considered to have MIH if one or more FPM with or without involvement of incisors met the diagnostic criteria. Results. MIH showed a prevalence of 8.6%. Demarcated opacities were the most common form. Maxillary central incisors were more affected than mandibular (P = 0.01). The condition was more prevalent in children with history of illnesses during the first four years of life including tonsillitis (P = 0.001), adenoiditis (P = 0.001), asthma (P = 0.001), fever (P = 0.014), and antibiotics intake (P = 0.001). Conclusions. The prevalence of MIH is significantly associated with childhood illnesses during the first four years of life including asthma, adenoid infections, tonsillitis, fever, and antibiotics intake. PMID:24949012

Allazzam, Sulaiman Mohammed; Alaki, Sumer Madani; El Meligy, Omar Abdel Sadek

2014-01-01

45

The association between traumatic dental injuries and atypical external root resorption in maxillary primary incisors.  

PubMed

Atypical root resorption (ARR), which is observed on radiographs of primary incisors, has been reported in the dental literature to result from digit sucking; thus ignoring any association between ARR and traumatic dental injuries (TDI). The purpose of this study was to evaluate and compare the contributions of sucking habits and TDI to external ARR in primary incisors. A history of dental trauma was assessed based on clinical and radiographic findings. Periapical radiographs of the premaxilla were evaluated for the presence of ARR. The presence or history of sucking habits was based on parents' report. Data were collected from files of 727 patients with a mean age of 52 months. Sixty-four children (8.8%) presented ARR in one or both central incisors. All 64 had experienced some type of TDI. Five hundred and forty-nine (76%) of the children had sucking habits; of them, 501 were pacifier-suckers and 48 digit suckers. Digit sucking was found in only 4 (6%) of the 64 children presenting ARR. These findings support the association of traumatic dental injury, and not of digit sucking, with ARR in primary incisors. PMID:25283588

Holan, Gideon; Yodko, Elizabeth; Sheinvald-Shusterman, Kineret

2015-02-01

46

Upper incisors' positions after extraction.  

PubMed

The aim of this research was to verify the amount of horizontal and vertical movement and incisor inclination of upper incisors and correlate these with Edgewise and Alexander brackets use and the presence of overbite during anterior retraction in sliding mechanics. The sample was composed of 40 adult patients divided into 2 groups, treated with Edgewise and Alexander brackets (20 each) subdivided in 2 groups (10 each), according to the presence or absence of deep bite. Treatment consisted of 4 extraction cases with sliding mechanics with the 2 different brackets. Pre- and post-treatment cephalograms were measured and the values of interest submitted to descriptive statistical analysis, ANOVA at 5%, the Tukey test and Pearson's correlation. Upper incisor retraction was not related to the brackets used nor to the presence of deep bite, though lingual tipping was greater when Edgewise brackets were used and deep bite was absent. No statistically significant differences in upper incisor vertical movements were observed and no correlation was determined between upper incisor intrusion and lower incisor labial tipping in overbite correction or in upper incisor retraction and lower incisor labial tipping for overjet correction. Bracket prescription and its interaction with deep bite were significant and Edgewise brackets without deep bite showed the worst inclination control. It was concluded that bracket prescriptions are important to increase control of sliding mechanics. PMID:24812742

Werneck, Eduardo César; Mattos, Fernanda Silva; Cotrim-Ferreira, Flávio Augusto; Prado, Renata Falchete; Silva, Márcio Garcia; Araújo, Adriano Marotta

2014-01-01

47

Post-traumatic impaction of maxillary incisors: diagnosis and treatment  

PubMed Central

Summary Aim To provide clinicians with useful information for immediate diagnosis and management of impacted maxillary incisors due to trauma. Methods We present a case of post-traumatic impaction of a central right maxillary incisor in a young patient. The treatment plan consisted in the interceptive management (surgical and orthodontic), the valuation of the necessary space to move the impacted tooth in the normal position and the biomechanical approach for anchorage, avoiding prosthetic/implants replacement. Results The therapy of an impacted maxillary incisor due to trauma requires a multidisciplinary approach: orthodontic, surgical, endodontic and periodontal considerations are essential for successful treatment. Conclusions Surgical exposure and orthodontic traction is the treatment most often used in case of posttraumatic impacted incisor: this technique in fact can lead to suitable results at the periodontal, occlusal and esthetics levels at an early stage and more definitively than with other treatment options. PMID:23991268

Paoloni, Valeria; Pavoni, Chiara; Mucedero, Manuela; Bollero, Patrizio; Laganà, Giuseppina; Cozza, Paola

2013-01-01

48

Maxillary canine transposition to incisor site: a rare condition.  

PubMed

Tooth transposition is defined as positional interchange of 2 adjacent teeth within the same quadrant. The incidence has been reported as about 0.4%, and the maxillary permanent canine has been reported as the tooth most frequently involved. Several etiologic factors like genetics, interchange in position of the developing tooth buds, trauma, mechanical interferences, and early loss of incisors have been associated with tooth transposition. Articles in the literature report various kinds of transpositions, but there are only a few reported cases of transposition of the maxillary canine to central incisor site. This kind of transposition has been suggested as resulting primarily by opportunistic canine migration into the space left from an early lost central incisor. However, there are only 2 long-term roentgenographic follow-up studies documenting maxillary canine migration and substantiating this hypothesis. This report shows 2 cases of this rare condition, with 1 of them documented with long-term records. PMID:15825796

Türkkahraman, Hakan; Sayin, M Ozgür; Yilmaz, H Hüseyin

2005-03-01

49

Familial aggregation of maxillary lateral incisor agenesis (MLIA)  

PubMed Central

Agenesis of maxillary lateral incisors and mandibular second premolars is the most frequent form of hypodontia. Its prevalence varies across population from 0.8% to 4.5%. Genetic aberrations and environmental factors may cause agenesis of one or more teeth. The management of child having such a problem is very important since diastema in teeth especially in upper anteriors not only affects child's physical appearance but also its psychological development as the child wants to look like other children. In this article is presented a case of non-syndromic agenesis of maxillary lateral incisors (MLIA) and mandibular central incisors in a 10-year-old boy (patient) in permanent dentition with its management along with the radiographic investigations and photographic presentations of the other members of his family affected with this condition. PMID:23536620

Pandey, Pallavi; Ansari, Afroz Alam; Choudhary, Kartik; Saxena, Aditya

2013-01-01

50

Radiographic Investigation of Frequency and Location of Root Canal Curvatures in Human Mandibular Anterior Incisors In Vitro  

Microsoft Academic Search

The aim of the present in vitro study was to evaluate the degree and location of root canal curvatures of mandibular anterior incisors. A total of 396 extracted human permanent anterior incisors (248 central and 148 lateral) were included in this investigation. Exclusion criteria were teeth with extensive carious lesions, restorations, and root canal treatment. The specimens were fixed in

Brita Willershausen; Adrian Kasaj; Bernd Röhrig; Benjamin Briseño Marroquin

2008-01-01

51

Impacted permanent incisors associated with compound odontoma.  

PubMed

Odontomas are the most common odontogenic tumours of the maxillary bones, characterised by a slow growth and benign behaviour. They are usually small, asymptomatic and diagnosed after routine radiographic examination. The aim of this study was to report a case of a compound odontoma in the anterior maxilla of a 7-year-old girl, which was causing the impaction of the maxillary right central and lateral incisors, as well as the prolonged retention of the corresponding primary teeth. We also aimed to review the literature about these tumours, since they are not part of the dentist's day-to-day clinical practice. The clinical and radiographic features, the diagnosis and treatment of the case were discussed in this work. PMID:25583937

Machado, Cintia de Vasconcellos; Knop, Luégya Amorin Henriques; da Rocha, Maria Celina Barreiros Siquara; Telles, Paloma Dias da Silva

2015-01-01

52

Aggressive dentigerous cyst with ectopic central incisor.  

PubMed

Dentigerous cysts form from accumulation of fluid between reduced enamel epithelium and the crown of an unerupted tooth. They cause several difficulties such as swelling, non-eruption of the involved teeth, and displacement of adjacent teeth, and thus require early detection and prompt treatment. Treatment ranges from marsupialisation to enucleation. Enucleation is rarely used in children compared with marsupialisation. This paper discusses successful use of enucleation for treating a dentigerous cyst and explains the need for such a radical procedure. PMID:24913076

Jayam, Cheranjeevi; Mitra, Malay; Bandlapalli, Anila; Jana, Biswanath

2014-01-01

53

Interdisciplinary treatment including forced extrusion and reintrusion of a traumatized mandibular incisor for a patient with Class II Division 1 skeletal open bite  

Microsoft Academic Search

A woman with Class II Division 1 long-face syndrome characteristics had a history of facial trauma, dentoalveolar fracture of her mandibular anterior teeth, and temporomandibular joint pain. The pretreatment apical radiograph showed a large area of external root resorption of the mesial surface of the mandibular left central incisor. To arrest the external root resorption, the mandibular left central incisor

Michael G Arvystas; Noah Chivian

2004-01-01

54

Calcium hydroxide induced apical barrier in fractured nonvital immature permanent incisors.  

PubMed

Management of trauma to an immature permanent incisor is a challenge, especially when the pulp is necrotic. The aim of this study is to discuss the management of fractured maxillary right and left central incisors with immature root apex. Radiographic evaluation revealed that the tooth 11 had convergent apical walls, whereas tooth 21 had parallel apical walls; both the incisors were treated with pure calcium hydroxide paste to induce apical development. Follow-up clinical and radiographic examinations confirmed apical barrier at 3 months. Radiograph of tooth 11 with convergent roots showed continued apical development, whereas tooth 21 showed apical bridging, following which root canal was completed in both the teeth. Therefore, in view of the simplicity of this method, we believe that calcium hydroxide can be reemphasized as one of the treatment alternatives for fractured nonvital immature permanent incisors to induce apical barrier. PMID:20660978

Vellore, K G

2010-01-01

55

Revascularization of immature permanent incisors after severe extrusive luxation injury.  

PubMed

Pulp necrosis is an uncommon sequel to extrusive luxation in immature teeth with incomplete apical closure. In this report, we describe the management of severely extruded immature maxillary incisors and the outcome of revascularization to treat subsequent pulp necrosis. An 8.5-year-old boy with severe dentoalveolar trauma to the anterior maxillary region as a result of a fall was provided emergency treatment consisting of reduction of the dislodged labial cortical bone and repositioning of the central incisors, which had suffered extrusive luxation. When he presented with spontaneous pain involving the traumatized incisors a week later, the teeth were treated via a revascularization protocol using sodium hypochlorite irrigation followed by 3 weeks of intracanal calcium hydroxide, then a coronal seal of mineral trioxide aggregate and resin composite. Complete periradicular healing was observed after 3 months, followed by progressive thickening of the root walls and apical closure. Follow-up observations confirmed the efficacy of the regenerative treatment as a viable alternative to conventional apexification in endodontically involved, traumatized immature teeth. PMID:23777005

Cehreli, Zafer C; Sara, Sezgi; Aksoy, Burak

2013-03-01

56

Revascularization of immature permanent incisors after severe extrusive luxation injury.  

PubMed

Pulp necrosis is an uncommon sequel to extrusive luxation in immature teeth with incomplete apical closure. In this report, we describe the management of severely extruded immature maxillary incisors and the outcome of revascularization to treat subsequent pulp necrosis. An 8.5-Year-old boy with severe dentoalveolar trauma to the anterior maxillary region as a result of a fall was provided emergency treatment consisting of reduction of the dislodged labial cortical bone and repositioning of the central incisors, which had suffered extrusive luxation. When he presented with spontaneous pain involving the traumatized incisors a week later, the teeth were treated via a revascularization protocol using sodium hypochlorite irrigation followed by 3 weeks of intracanal calcium hydroxide, then a coronal seal of mineral trioxide aggregate and resin composite. Complete periradicular healing was observed after 3 Months, followed by progressive thickening of the root walls and apical closure. Follow-up observations confirmed the efficacy of the regenerative treatment as a viable alternative to conventional apexification in endodontically involved, traumatized immature teeth. PMID:22322021

Cehreli, Zafer C; Sara, Sezgi; Aksoy, Burak

2012-01-01

57

Revascularization of immature permanent incisors after severe extrusive luxation injury.  

PubMed

Pulp necrosis is an uncommon sequel to extrusive luxation in immature teeth with incomplete apical closure. In this report, we describe the management of severely extruded immature maxillary incisors and the outcome of revascularization to treat subsequent pulp necrosis. An 8.5-year-old boy with severe dentoalveolar trauma to the anterior maxillary region as a result of a fall was provided emergency treatment consisting of reduction of the dislodged labial cortical bone and repositioning of the central incisors, which had suffered extrusive luxation. When he presented with spontaneous pain involving the traumatized incisors a week later, the teeth were treated via a revascularization protocol using sodium hypochlorite irrigation followed by 3 weeks of intracanal calcium hydroxide, then a coronal seal of mineral trioxide aggregate and resin composite. Complete periradicular healing was observed after 3 months, followed by progressive thickening of the root walls and apical closure. Follow-up observations confirmed the efficacy of the regenerative treatment as a viable alternative to conventional apexification in endodontically involved, traumatized immature teeth. PMID:22916525

Cehreli, Zafer C; Sara, Sezgi; Aksoy, Burak

2012-07-01

58

Incisor wear and age in Yellowstone bison  

USGS Publications Warehouse

Biologists commonly use tooth eruption and wear patterns or cementum annuli techniques to estimate age of ungulates. However, in some situations the accuracy or sampling procedures of either approach are undesirable. We investigated the progression of several quantitative measures of wear with age, using permanent first incisors from Yellowstone bison (Bison bison), and tested for differences between sexes and herds. We further investigated the relationship of wear and age to explore an age-estimation method. Labial-lingual width (LLW) correlated best with assigned age (r2=0.66, males; r2=0.76 females). Labial-lingual width differed between sexes, with females showing ???0.2 mm more wear than males. Additionally, differences in rate of wear existed between bison of the northern and central Yellowstone herds (1.2 and 0.9 mm/year, respectively). We developed a regression formula to test the power of LLW as an estimator of Yellowstone bison age. Our method provided estimated ages within 1 year of the assigned age 73% and 82% of the time for female and male bison, respectively.

Christianson, D.A.; Gogan, P.J.P.; Podruzny, K.M.; Olexa, E.M.

2005-01-01

59

Impacted maxillary incisors: diagnosis and predictive measurements  

PubMed Central

Summary Background When the incisors do not erupt at the expected time, it is crucial for the clinician to determine the etiology and formulate an appropriate treatment plan. Aim The aim of this report is to provide useful information for immediate diagnosis and management of impacted maxillary incisors using the interceptive treatment: removal of obstacles and rapid maxillary expansion (RME). Design An accurate diagnosis may be obtained with clinical and radiographic exam such as panoramic radiograph, computerized tomography (CT) and cone beam computerized tomography (CBCT). It’s important to know the predictive measurements of eruption evaluated on panoramic radiograph: distance from the occlusal plane, maturity, angulation and vertical position of the unerupted incisors. Early diagnosis is important and interceptive orthodontic treatment, such as removal of obstacles and orthopedic rapid maxillary expansion (RME), may correct disturbances during the eruption through recovering space for the incisors and improving the intraosseus position of delayed teeth. Results RME treatment following the surgical removal of the obstacle to the eruption of maxillary incisors leads to an improvement of the intraosseus position of the tooth. Conclusions The angulation and the vertical position of the delayed tooth appear to be important in trying to predict eruption. The improvement of the intraosseus position of the unerupted incisor, obtained by removal of the odontoma and rapid maxillary expansion, permits a conservative surgery and the achievement of an excellent esthetics and periodontal result. PMID:23386930

Pavoni, Chiara; Mucedero, Manuela; Laganà, Giuseppina; Paoloni, Valeria; Cozza, Paola

2012-01-01

60

Removable orthodontic appliance with nickel-titanium spring to reposition the upper incisors in an autistic patient.  

PubMed

A newly designed removable appliance with a shape-memory wire was used for the orthodontic treatment of the anterior teeth in an 11-year-old child who had autism and intellectual disability. The device was designed to reduce the lateral incisor crossbite and the central incisors' labial rotation. The child was treated for 1 year with this removable appliance. Tooth movement was analyzed using cephalograms and surface data were derived from study models. This device proved to be very durable. The lateral incisor crossbite was corrected, and the inclination of the upper central incisors and the interincisal angle were improved. This appliance exerts light and continuous orthodontic force, without requiring any adjustments of the spring wire. The appliance also facilitated orthodontic treatment in a child with intellectual disability in whom treatment with a standard orthodontic device would be unsuitable. PMID:23278147

Saito, Kan; Jang, Insan; Kubota, Kazumi; Hoshino, Tomonori; Hotokezaka, Hitoshi; Yoshida, Noriaki; Fujiwara, Taku

2013-01-01

61

Complete Bilateral Gemination of Maxillary Incisors with Separate Root Canals  

PubMed Central

Developmental anomalies in the hard tissue are seen frequently in dental practice. Gemination and fusion are the most commonly encountered anomalies, and distinction between the two is always challenging. Gemination, also called double tooth, is an anomaly exhibiting two joined crowns and usually a single root. It represents an incomplete attempt of a single tooth germ to split. It is considered multifactorial in etiology, with genetic and environmental causes. This paper discusses a rare example of bilateral gemination (prevalence 0.04%) of maxillary central incisors with completely separated roots. Multidisciplinary care ensured a successful esthetic and functional outcome. PMID:25254121

Mahendra, Lodd; Govindarajan, Sujatha; Jayanandan, Muruganandhan; Shamsudeen, Shaik Mohammed; Kumar, Nalin; Madasamy, Ramasamy

2014-01-01

62

Signaling by FGFR2b controls the regenerative capacity of adult mouse incisors  

PubMed Central

Rodent incisors regenerate throughout the lifetime of the animal owing to the presence of epithelial and mesenchymal stem cells in the proximal region of the tooth. Enamel, the hardest component of the tooth, is continuously deposited by stem cell-derived ameloblasts exclusively on the labial, or outer, surface of the tooth. The epithelial stem cells that are the ameloblast progenitors reside in structures called cervical loops at the base of the incisors. Previous studies have suggested that FGF10, acting mainly through fibroblast growth factor receptor 2b (FGFR2b), is crucial for development of the epithelial stem cell population in mouse incisors. To explore the role of FGFR2b signaling during development and adult life, we used an rtTA transactivator/tetracycline promoter approach that allows inducible and reversible attenuation of FGFR2b signaling. Downregulation of FGFR2b signaling during embryonic stages led to abnormal development of the labial cervical loop and of the inner enamel epithelial layer. In addition, postnatal attenuation of signaling resulted in impaired incisor growth, characterized by failure of enamel formation and degradation of the incisors. At a cellular level, these changes were accompanied by decreased proliferation of the transit-amplifying cells that are progenitors of the ameloblasts. Upon release of the signaling blockade, the incisors resumed growth and reformed an enamel layer, demonstrating that survival of the stem cells was not compromised by transient postnatal attenuation of FGFR2b signaling. Taken together, our results demonstrate that FGFR2b signaling regulates both the establishment of the incisor stem cell niches in the embryo and the regenerative capacity of incisors in the adult. PMID:20978072

Parsa, Sara; Kuremoto, Koh-ichi; Seidel, Kerstin; Tabatabai, Reza; MacKenzie, BreAnne; Yamaza, Takayoshi; Akiyama, Kentaro; Branch, Jonathan; Koh, Chester J.; Alam, Denise Al; Klein, Ophir D.; Bellusci, Saverio

2010-01-01

63

Two hominin incisor teeth from the middle Pleistocene site of Boxgrove, Sussex, England.  

PubMed

In 1995-1996 two isolated hominin lower incisors were found at the middle Pleistocene site of Boxgrove in England, with Lower Palaeolithic archaeology. Boxgrove 2 is a permanent lower right central incisor and Boxgrove 3 a permanent lower left lateral incisor. They were found separately, but close to one another and appear to belong to the same individual. The Boxgrove 1 tibia discovered in 1993 came from a different stratigraphic context and is thus believed to represent a different individual. This paper describes the morphology of the incisors, which is similar to other middle Pleistocene hominin specimens and, as with the tibia, suggests that they could be assigned to Homo heidelbergensis (recognising that the taxonomic status of this species is still a matter of debate). The incisors show substantial attrition associated with secondary dentine deposition in the pulp chamber and clearly represent an adult. They also show extensive patterns of non-masticatory scratches on the labial surfaces of both crown and root, including some marks which may have been made postmortem. The roots were exposed in life on their labial sides by a large dehiscence, extending almost to the root apex. This is demonstrated by deposits of calculus, polishing, and scratching on the exposed surfaces. The dehiscence may have been caused by repeated trauma to the gingivae or remodelling of the tooth-supporting tissues in response to large forces applied to the front of the dentition. PMID:20828787

Hillson, S W; Parfitt, S A; Bello, S M; Roberts, M B; Stringer, C B

2010-11-01

64

Incisor wear and age in Yellowstone bison  

Microsoft Academic Search

Biologists commonly use tooth eruption and wear patterns or cementum annuli tech- niques to estimate age of ungulates. However, in some situations the accuracy or sam- pling procedures of either approach are undesirable. We investigated the progression of several quantitative measures of wear with age, using permanent first incisors from Yellowstone bison (Bison bison), and tested for differences between sexes

David A. Christianson; Kevin M. Podruzny; Edward M. Olexa

2005-01-01

65

Comparative studies between mice molars and incisors are required to draw an overview of enamel structural complexity  

PubMed Central

In the field of dentistry, the murine incisor has long been considered as an outstanding model to study amelogenesis. However, it clearly appears that enamel from wild type mouse incisors and molars presents several structural differences. In incisor, exclusively radial enamel is observed. In molars, enamel displays a high level of complexity since the inner part is lamellar whereas the outer enamel shows radial and tangential structures. Recently, the serotonin 2B receptor (5-HT2BR) was shown to be involved in ameloblast function and enamel mineralization. The incisors from 5HT2BR knockout (KO) mice exhibit mineralization defects mostly in the outer maturation zone and porous matrix network in the inner zone. In the molars, the mutation affects both secretory and maturation stages of amelogenesis since pronounced alterations concern overall enamel structures. Molars from 5HT2BR KO mice display reduction in enamel thickness, alterations of inner enamel architecture including defects in Hunter-Schreger Bands arrangements, and altered maturation of the outer radial enamel. Differences of enamel structure were also observed between incisor and molar from other KO mice depleted for genes encoding enamel extracellular matrix proteins. Thus, upon mutation, enamel analysis based exclusively on incisor defects would be biased. In view of the functional relationship between enamel structure and tooth morphogenesis, identification of molecular actors involved in amelogenesis requires comparative studies between mice molars and incisors. PMID:25285079

Goldberg, Michel; Kellermann, O.; Dimitrova-Nakov, S.; Harichane, Y.; Baudry, A.

2014-01-01

66

Molars and incisors: show your microarray IDs  

PubMed Central

Background One of the key questions in developmental biology is how, from a relatively small number of conserved signaling pathways, is it possible to generate organs displaying a wide range of shapes, tissue organization, and function. The dentition and its distinct specific tooth types represent a valuable system to address the issues of differential molecular signatures. To identify such signatures, we performed a comparative transcriptomic analysis of developing murine lower incisors, mandibular molars and maxillary molars at the developmental cap stage (E14.5). Results 231 genes were identified as being differentially expressed between mandibular incisors and molars, with a fold change higher than 2 and a false discovery rate lower than 0.1, whereas only 96 genes were discovered as being differentially expressed between mandibular and maxillary molars. Numerous genes belonging to specific signaling pathways (the Hedgehog, Notch, Wnt, FGF, TGF?/BMP, and retinoic acid pathways), and/or to the homeobox gene superfamily, were also uncovered when a less stringent fold change threshold was used. Differential expressions for 10 out of 12 (mandibular incisors versus molars) and 9 out of 10 selected genes were confirmed by quantitative reverse transcription-PCR (qRT-PCR). A bioinformatics tool (Ingenuity Pathway Analysis) used to analyze biological functions and pathways on the group of incisor versus molar differentially expressed genes revealed that 143 genes belonged to 9 networks with intermolecular connections. Networks with the highest significance scores were centered on the TNF/NF?B complex and the ERK1/2 kinases. Two networks ERK1/2 kinases and tretinoin were involved in differential molar morphogenesis. Conclusion These data allowed us to build several regulatory networks that may distinguish incisor versus molar identity, and may be useful for further investigations of these tooth-specific ontogenetic programs. These programs may be dysregulated in transgenic animal models and related human diseases leading to dental anomalies. PMID:23531410

2013-01-01

67

Dental fast track: Prenatal enamel growth, incisor eruption, and weaning in human infants.  

PubMed

Correlation between the timing of permanent first molar eruption and weaning age in extant primates has provided a way to infer a life history event in fossil species, but recent debate has questioned whether the same link is present in human infants. Deciduous incisors erupt at an age when breast milk can be supplemented with additional foods (mixed feeding), and weaning is typically complete before permanent first molars erupt. Here, I use histological methods to calculate the prenatal rate by which enamel increases in thickness and height on human deciduous incisors, canines, and molars (n = 125). Growth trajectories for each tooth type are related to the trimesters and assessed against the eruption sequence and final crown height. Analyses show that central incisors initiate early in the second trimester with significantly faster secretion rates relative to canines and second molars, which initiate closer to birth. Even though initial extension rates were correlated with crown height and scaled with positive allometry within each tooth class, the relatively short incisors still increased in height at a significantly faster rate than the taller canines and molars. The incisor prenatal "fast track" produces a greater proportion of the crown before birth than all other tooth types. This growth mechanism likely facilitates early incisor eruption at a time when the mixed feeding of infants can be initiated as part of the weaning process. Findings provide a basis from which to explore new links between developmental trends along the tooth row and mixed feeding age in other primates. Am J Phys Anthropol 156:407-421, 2015. © 2014 Wiley Periodicals, Inc. PMID:25388809

Mahoney, Patrick

2015-03-01

68

Quantum-walk-based search and centrality  

SciTech Connect

We study the discrete-time quantum-walk-based search for a marked vertex on a graph. By considering various structures in which not all vertices are equivalent, we investigate the relationship between the successful search probability and the position of the marked vertex, in particular, its centrality. We find that the maximum value of the search probability does not necessarily increase as the marked vertex becomes more central, and we investigate an interesting relationship between the frequency of the successful search probability and the centrality of the marked vertex.

Berry, Scott D.; Wang, Jingbo B. [School of Physics, The University of Western Australia, Perth, WA 6009 (Australia)

2010-10-15

69

Dynamics-based centrality for directed networks  

NASA Astrophysics Data System (ADS)

Determining the relative importance of nodes in directed networks is important in, for example, ranking websites, publications, and sports teams, and for understanding signal flows in systems biology. A prevailing centrality measure in this respect is the PageRank. In this work, we focus on another class of centrality derived from the Laplacian of the network. We extend the Laplacian-based centrality, which has mainly been applied to strongly connected networks, to the case of general directed networks such that we can quantitatively compare arbitrary nodes. Toward this end, we adopt the idea used in the PageRank to introduce global connectivity between all the pairs of nodes with a certain strength. Numerical simulations are carried out on some networks. We also offer interpretations of the Laplacian-based centrality for general directed networks in terms of various dynamical and structural properties of networks. Importantly, the Laplacian-based centrality defined as the stationary density of the continuous-time random walk with random jumps is shown to be equivalent to the absorption probability of the random walk with sinks at each node but without random jumps. Similarly, the proposed centrality represents the importance of nodes in dynamics on the original network supplied with sinks but not with random jumps.

Masuda, Naoki; Kori, Hiroshi

2010-11-01

70

Inadvertent MTA extrusion in an immature traumatized permanent incisor.  

PubMed

This report describes the 24-month clinical and radiographic outcome of an unintentionally extruded mineral trioxide aggregate (MTA) apical plug. A 9 year old boy presented with a previously traumatized, immature central incisor; associated with a large periradicular lesion. During placement of MTA in the treatment of wide open apex, the material was inadvertently extruded into the periapical region upon a sudden movement of the child. No intervention was made, except for obturation of the remaining root canal two weeks later. The radiographic follow up at 12 and 24 months confirmed successful management through the non surgical approach, as evidenced by advanced healing of the periapical lesion and regeneration of the periradicular tissue in the absence of clinical symptoms. PMID:21417115

Tezel, Bahar; Uysal, Serdar; Turgut, Melek D; Cehreli, Zafer C

2010-01-01

71

Reattachment of fractured teeth fragments in mandibular incisors: a case report  

PubMed Central

The majority of dental trauma involves anterior teeth, especially the maxillary central incisors. A mandibular incisor fracture with or without pulp tissue involvement is considerably less common. Different approaches for treating these fractured teeth have been reported in the literature. The type of treatment rendered depends mainly on the extent of fracture, pulp involvement, radicular fracture, biologic width infringement or violation, and presence of the fractured piece. This case report illustrates reattachment of fractured fragments on two mandibular incisors without pulp exposure using a new proposed reattachment method using a combination of two different types of composite materials together with an orthodontic lingual retention wire. An 8-year-old female patient presented with fractured mandibular left incisors (Ellis class II fracture). Broken pieces were saved and brought in a closed container in water. Periapical radiographs revealed no evidence of pulpal involvement in either tooth and no periapical radiolucency was noticed. Fractured fragments and the broken teeth were prepared with circumferential bevels. Reattachment of the fractured fragments were done using two types of composite resin materials and a lingual orthodontic retention wire was also used. The patient was recalled after 8 months to follow up both teeth. Clinical examination revealed excellent composite restorations covering the fracture lines.

Yousef, Mohammed K

2015-01-01

72

First records of talon cusps on baboon maxillary incisors argue for standardizing terminology and prompt a hypothesis of their formation.  

PubMed

Dental characters can provide vital clues for understanding intra- and intertaxonomic morphological variation and its underlying genetic and environmental components. However, the unambiguous identification of particular traits and their comparative study is often confounded by lack of consistent terminology in the relevant literature. This difficulty is exacerbated when the etiologies are not completely understood, as is the case with talon cusps. To date, research on talon cusps has focused on modern humans. In many instances, descriptions of talon cusps appear in clinical case studies focusing on their treatment and removal. What is lacking in those discussions, though, is a comparative framework, in which the occurrence of talon cusps in nonhuman primates, and possibly other mammals, is established and understood. Here, we report on a taloned upper central incisor of a wild baboon (Papio hamadryas ursinus) from South Africa. The anomalous incisor of this individual includes an exaggerated accessory cusp diagnosed as a Type II talon. Microcomputed tomographic and radiographic analyses show that the taloned cusp possesses enamel, dentin, and pulp. In addition, we identified an unclassifiable talon cusp on a central maxillary incisor of a baboon skull housed in the Smithsonian Institution's Natural History Museum collection. Our observations of talon cusps on baboon incisors demonstrate that, with regard to this phenomenon, systematic study of nonhuman primates is much needed, along with a consistent use of terminology in the anatomical and anthropological literature. Finally, we present a hypothesis of the formation of talon cusps on mammalian incisors. PMID:24173685

Heaton, Jason L; Pickering, Travis Rayne

2013-12-01

73

E-cadherin regulates the behavior and fate of epithelial stem cells and their progeny in the mouse incisor  

PubMed Central

Stem cells are essential for the regeneration and homeostasis of many organs, such as tooth, hair, skin, and intestine. Although human tooth regeneration is limited, a number of animals have evolved continuously growing teeth that provide models of stem cell-based organ renewal. A well-studied model is the mouse incisor, which contains dental epithelial stem cells in structures known as cervical loops. These stem cells produce progeny that proliferate and migrate along the proximo-distal axis of the incisor and differentiate into enamel-forming ameloblasts. Here, we studied the role of E-cadherin in behavior of the stem cells and their progeny. Levels of E-cadherin are highly dynamic in the incisor, such that E-cadherin is expressed in the stem cells, downregulated in the transit-amplifying cells, re-expressed in the pre-ameloblasts and then downregulated again in the ameloblasts. Conditional inactivation of E-cadherin in the cervical loop led to decreased numbers of label-retaining stem cells, increased proliferation, and decreased cell migration in the mouse incisor. Using both genetic and pharmacological approaches, we showed that Fibroblast Growth Factors regulate E-cadherin expression, cell proliferation and migration in the incisor. Together, our data indicate that E-cadherin is an important regulator of stem cells and their progeny during growth of the mouse incisor. PMID:22537490

Li, Chun-Ying; Cha, Wanghee; Luder, Hans-Ulrich; Charles, Roch-Philippe; McMahon, Martin; Mitsiadis, Thimios; Klein, Ophir D.

2013-01-01

74

Interim Restorative Approach for the Management of Congenitally Missing Permanent Mandibular Incisors: Presentation of Three Cases  

PubMed Central

Congenital missing of mandibular permanent incisors with retained primary incisors may jeopardize the esthetic appearance and psychological development of children, especially during the years of transition into adolescence. The retained primary teeth are necessary for the maintenance and normal development of alveolar bone, which in turn is essential for future definitive rehabilitation. In such situations, an interim restoration may be provided before any definitive treatment is given to comfort the young patient during this transition period. Interim restorations may include resin-modified additions to the existing teeth as well as more sophisticated restorations such as resin-retained bridge and removable partial dentures. However, this restoration differs for different clinical situations based on various factors such as age and patient compliance, and also consideration has to be given for the growth changes of the child. The aim of this present paper is to discuss the esthetic management of three cases with bilateral agenesis of permanent mandibular incisors and retained primary incisors with composite interim restoration. PMID:22567446

Prakash, Prashanth; Hallur, Jayadev M.; Gowda, Rachana Narse

2011-01-01

75

Immunohistochemical localization of SNARE proteins in dental pulp and periodontal ligament of the rat incisor.  

PubMed

Distribution of three soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) proteins, syntaxin-1, synaptosomal-associated protein of 25 kDa (SNAP-25), and vesicle-associated membrane protein-2 (VAMP-2), was examined in dental pulp and periodontal ligament of the rat incisor. In the trigeminal ganglion, syntaxin-1 and SNAP-25 immunoreactivity was predominately detected in medium- to large-sized neurons. Most syntaxin-1 immunoreactive neurons expressed SNAP-25. In contrast, VAMP-2 was localized in small- to medium-sized neurons and in slender-shaped cells surrounding SNAP-25-immunopositive neurons. When the inferior alveolar nerve, one of the mandibular nerve branches innervating the dental pulp and periodontal ligament, was ligated, SNARE proteins accumulated at the site proximal to the ligation. In the incisor dental pulp, all nerve fibers displayed immunoreactivity for syntaxin-1, SNAP-25, and VAMP-2. In the periodontal ligament of the incisor, almost all nerve fibers displayed both syntaxin-1 and SNAP-25 immunoreactivity, but lacked VAMP-2 immunoreactivity. SNAP-25 protein expression was localized around the vesicle membranes at the axon terminal of the periodontal mechanoreceptors. These present data suggest that these three SNARE proteins are synthesized at the trigeminal ganglion, transported centrally and peripherally, and expressed in sensory endings where apparent synapses are not present. Because those proteins participate in docking and exocytosis of synapse vesicles in the central nervous system, they might also contribute to vesicle exocytosis at receptive fields where apparent synapses are not present. PMID:20186959

Honma, Shiho; Taki, Kunitaka; Lei, Shi; Niwa, Hitoshi; Wakisaka, Satoshi

2010-06-01

76

The Adaptive Significance of Enamel Loss in the Mandibular Incisors of Cercopithecine Primates (Mammalia: Cercopithecidae): A Finite Element Modelling Study  

PubMed Central

In several primate groups enamel is reduced or absent from the lingual (tongue) side of the mandibular incisor crowns akin to other placental and marsupial mammalian groups such as rodents, lagomorphs and wombats. Here we investigate the presumed adaptation of crowns with unilateral enamel to the incision of tough foods in cercopithecines, an Old World monkey subfamily, using a simulation approach. We developed and validated a finite element model of the lower central incisor of the rhesus macaque (Macaca mulatta) with labial enamel only to compute three-dimensional displacements and maximum principal stresses on the crown subjected to compressive loads varying in orientation. Moreover, we developed a model of a macaque incisor with enamel present on both labial and lingual aspects, thus resembling the ancestral condition found in the sister taxon, the leaf-eating colobines. The results showed that, concomitant with experimental results, the cercopithecine crown with unilateral enamel bends predominantly towards the inside of the mouth, while displacements decreased when both labial and lingual enamel are present. Importantly, the cercopithecine incisor crown experienced lower maximum principal stress on the lingual side compared to the incisor with enamel on the lingual and labial aspects under non-axial loads directed either towards the inside or outside of the mouth. These findings suggest that cercopithecine mandibular incisors are adapted to a wide range of ingestive behaviours compared to colobines. We conclude that the evolutionary loss of lingual enamel in cercopithecines has conferred a safeguard against crown failure under a loading regime assumed for the ingestion (peeling, scraping) of tough-skinned fruits. PMID:24831704

Kupczik, Kornelius; Lev-Tov Chattah, Netta

2014-01-01

77

The adaptive significance of enamel loss in the mandibular incisors of cercopithecine primates (Mammalia: Cercopithecidae): a finite element modelling study.  

PubMed

In several primate groups enamel is reduced or absent from the lingual (tongue) side of the mandibular incisor crowns akin to other placental and marsupial mammalian groups such as rodents, lagomorphs and wombats. Here we investigate the presumed adaptation of crowns with unilateral enamel to the incision of tough foods in cercopithecines, an Old World monkey subfamily, using a simulation approach. We developed and validated a finite element model of the lower central incisor of the rhesus macaque (Macaca mulatta) with labial enamel only to compute three-dimensional displacements and maximum principal stresses on the crown subjected to compressive loads varying in orientation. Moreover, we developed a model of a macaque incisor with enamel present on both labial and lingual aspects, thus resembling the ancestral condition found in the sister taxon, the leaf-eating colobines. The results showed that, concomitant with experimental results, the cercopithecine crown with unilateral enamel bends predominantly towards the inside of the mouth, while displacements decreased when both labial and lingual enamel are present. Importantly, the cercopithecine incisor crown experienced lower maximum principal stress on the lingual side compared to the incisor with enamel on the lingual and labial aspects under non-axial loads directed either towards the inside or outside of the mouth. These findings suggest that cercopithecine mandibular incisors are adapted to a wide range of ingestive behaviours compared to colobines. We conclude that the evolutionary loss of lingual enamel in cercopithecines has conferred a safeguard against crown failure under a loading regime assumed for the ingestion (peeling, scraping) of tough-skinned fruits. PMID:24831704

Kupczik, Kornelius; Lev-Tov Chattah, Netta

2014-01-01

78

Evaluation of the relationship between upper incisor exposure and cephalometric variables in Korean young adults  

PubMed Central

Objective The purpose of this study was to classify Korean young adults into 3 groups on the basis of upper incisor exposure rates (UIERs) and to compare the skeletal, dental, and soft tissue variables. Methods Samples were obtained from 127 students at the College of Dentistry, Wonkwang University in South Korea. Facial photographs of frontal posed smiles and lateral cephalograms of the subjects were taken. The subjects were divided into 3 groups on the basis of UIERs and 20 measurements were compared among the 3 groups. The correlations between the variables were determined. Results Male and female subjects showed significant differences in the group distribution. Male subjects showed higher frequencies of low smiles, and female subjects showed higher frequencies of high smiles. The vertical height of the anterior alveolar process of the maxilla directly correlated with the UIER. However, the UIER showed no significant correlation with the vertical height of the anterior basal bone or the inclination of the upper incisor axis. In female subjects, the upper central incisor clinical crown length showed an inverse correlation with the UIER. However, this variable showed no significant correlation with the UIER in male subjects. Conclusions The UIER was directly correlated with the levator muscle activity of the upper lip and inversely correlated with the upper lip thickness, yet there was no correlation between the UIER and upper lip length at rest. PMID:24228237

Han, Sung-Hoon; Lee, Eon-Hwa; Cho, Jin-Hyoung; Chae, Jong-Moon; Kim, Sang-Cheol; Chang, Na-Young

2013-01-01

79

Treatment options for the replacement of missing mandibular incisors.  

PubMed

The replacement of a mandibular incisor is a dental treatment warranting special consideration. Some of the challenges associated with the anterior mandible are limited space, challenging surrounding anatomy, and tough esthetic requirements. Proper diagnosis and treatment planning may require a multidisciplinary approach to successfully meet the demands of replacing a missing tooth in this sextant. Several treatment options currently exist for mandibular incisor replacement. These options include (1) resin-bonded fixed dental prostheses (RBFDPs), (2) orthodontic treatment, (3) full-veneer fixed dental prostheses (FDPs), (4) dental implants for single-tooth replacement, (5) possible extraction of one or more incisors and restoration with implant-supported FDPs, (6) possible extraction of one or more teeth and restoration with FDPs from #22 to 27, (7) possible extraction of one or more teeth and restoration with removable dental prostheses (RDPs). This manuscript outlines the various treatment options for the replacement of mandibular incisors and discusses benefits and drawbacks of each. PMID:21631631

Fleigel, Jeffrey D; Salmon, Cade A; Piper, James M

2011-07-01

80

Cone beam-computed topographic evaluation of a central incisor with an open apex and a failed root canal treatment using one-step apexification with Biodentine™: A case report  

PubMed Central

A symptomatic endodontically treated immature tooth with periapical pathology presents multiple challenges to the clinician. Owing to incomplete root formation, gutta percha removal has to be done carefully without further damaging the periapical tissue or pushing the obturating material beyond the apex. Nonsurgical approach toward treating such a tooth would necessitate the creation of an apical barrier followed by conventional root canal treatment. Current literature suggests one-step apexification with mineral trioxide aggregate (MTA), with an apical matrix as the treatment of choice. A new calcium silicate-based cement also called as dentine substitute by the manufacturers with good handling properties has been introduced recently by the trade name Biodentine™ (Septodont, St. Maurdes Fossés, France). This case report presents management of a secondary endodontic case with an open apex treated with the concept of ‘lesion sterilization and tissue repair (LSTR)’ using triantibiotic paste and Biodentine™ for apical barrier formation. A 12-month follow up with cone beam-computed topography (CBCT) exhibited progressive involution of periapical radiolucency with indications of good healing of the periapical tissues and absence of clinical symptoms. PMID:24944456

Sinha, Nidhi; Singh, Bijay; Patil, Santosh

2014-01-01

81

Cone beam-computed topographic evaluation of a central incisor with an open apex and a failed root canal treatment using one-step apexification with Biodentine™: A case report.  

PubMed

A symptomatic endodontically treated immature tooth with periapical pathology presents multiple challenges to the clinician. Owing to incomplete root formation, gutta percha removal has to be done carefully without further damaging the periapical tissue or pushing the obturating material beyond the apex. Nonsurgical approach toward treating such a tooth would necessitate the creation of an apical barrier followed by conventional root canal treatment. Current literature suggests one-step apexification with mineral trioxide aggregate (MTA), with an apical matrix as the treatment of choice. A new calcium silicate-based cement also called as dentine substitute by the manufacturers with good handling properties has been introduced recently by the trade name Biodentine™ (Septodont, St. Maurdes Fossés, France). This case report presents management of a secondary endodontic case with an open apex treated with the concept of 'lesion sterilization and tissue repair (LSTR)' using triantibiotic paste and Biodentine™ for apical barrier formation. A 12-month follow up with cone beam-computed topography (CBCT) exhibited progressive involution of periapical radiolucency with indications of good healing of the periapical tissues and absence of clinical symptoms. PMID:24944456

Sinha, Nidhi; Singh, Bijay; Patil, Santosh

2014-05-01

82

Endodontic treatment of maxillary lateral incisors with anatomical variations  

PubMed Central

Maxillary lateral incisors usually exhibit a single root with a single canal. However, maxillary lateral incisor teeth with unusual morphology of root canal system are frequently reported. These cases of variable root canal anatomy can be treated well by nonsurgical endodontic methods. A detailed description of root canal morphology is fundamental for successful endodontic treatment. Treatment using an operating microscope, radiographs from different angles, and cone-beam computerized tomography (CBCT) can produce more predictable endodontic outcomes. PMID:24303362

Lee, Moon-Hwan; Ha, Jung-Hong; Jin, Myoung-Uk; Kim, Young-Kyung

2013-01-01

83

Replantation after extended dry storage of avulsed permanent incisors: report of a case.  

PubMed

A 15-year-old boy lost his maxillary right and left central incisor teeth in a bicycle accident. He was referred to our clinic 1 week after the injury. The crown-root integrities of both the teeth were not damaged. Although the teeth were stored under dry conditions for 1 week, reimplantation of the teeth was planned to retain the teeth in the mouth for as long a period as possible because of the patient's age. Following the debridement and sterilization of root surfaces in 2.5% NaOCl, root canals were prepared and filled with calcium hydroxide. Then, about 2 mm of the apexes were resected to ensure that the roots easily seated in the alveolar socket and the prepared cavities in root ends were obturated with the amalgam. The teeth were placed into their respective sockets and splinted temporarily. The root canal therapy was completed 5 weeks later. Ankylosis was observed radiographically after 10 months. The patient is now 23 years old and he is still able to use both the central incisors functionally. However, there is a pink appearance on the cervical buccal surface of left central incisor because of progressive replacement resorption. In this case, the new treatment plan is to perform a permanent restoration with dental implants following the extraction of both teeth. Even though the long-term prognosis is uncertain, this treatment technique has provided an advantage for the patient in his adolescent period by maintaining the height of alveolar bone and making the provision of an aesthetically acceptable permanent restoration at a later age possible. PMID:17635361

Cobankara, Funda Kont; Ungor, Mete

2007-08-01

84

Electron microprobe analyses of Ca, S, Mg and P distribution in incisors of Spacelab-3 rats  

NASA Technical Reports Server (NTRS)

The distribution of Ca, S, Mg and P was mapped within the incisors of Spacelab-3 rats using an electron microprobe. The data indicate that Flight rats maintained in orbit for 7 days have significantly higher Ca/Mg ratios in dentin due to both higher Ca and lower Mg content than in dentin of ground-based Controls. There is no statistical difference in distribution of either P or S within Fligth animals and Controls, but there is clear indication that, for P at least, the reason is the greater variability of the Control data. These results are consistent with those obtained on a previous NASA/COSMOS flight of 18.5 days duration, although they are not pronounced. The results further suggest that continuously growing rat incisors provide useful records of the effects of weightlessness on Ca metabolism.

Rosenberg, G. D.; Simmons, D. J.

1985-01-01

85

Dendritic cells and macrophages expressing class II antigens in the normal rat incisor pulp.  

PubMed

This study has identified and characterized class II (Ia) antigen-expressing cells in the normal rat incisor pulp by immunohistochemistry and flow cytometry. Two types of Ia-expressing cells occurred: one with a pronounced dendritic appearance located primarily in the periphery of the pulp, and one with morphological characteristics similar to those of macrophages. The latter cells were mainly observed in the central portion of the pulp. A numerical ratio of 1:4 was established between the two cell types. The existence of Ia-expressing cells suggests an inherent capacity of the pulp to process and present foreign antigens. PMID:3170880

Jontell, M; Bergenholtz, G; Scheynius, A; Ambrose, W

1988-10-01

86

A comparative study of different intrusion methods and their effect on maxillary incisors  

PubMed Central

Introduction To evaluate and compare the rate of intrusion and root resorption of maxillary incisors by three different intrusion techniques: Rickett's utility arch, Kalra's Simultaneous Intrusion & Retraction arch and arch with Reverse Curve of Spee. Methods The study was conducted over 30 patients aged between 14 and 25 yrs with deep bite requiring at least 2–4 mm intrusion of maxillary incisors. These patients were equally divided into three groups based on intrusion technique used, Rickets utility arch (Group I), K-SIR arch (Group II) and RCS arch (Group III). For each patient, amount of intrusion and root resorption occurring during intrusion was measured. Seven angular and six linear cephalometric measurements were made to evaluate skeletal and dental changes before and after incisor intrusion. Results The mean true incisor intrusion achieved with utility arch was 1.6 mm, with K-SIR, 1.25 mm and with RCS, 0.70 mm respectively. The rate of intrusion of utility arch was 0.44 mm/month, K-SIR – 0.33 mm/month, RCS – 0.35 mm/month, the difference was not statistically significant (p = 0.451). Utility arch had significantly higher mean root resorption of 1.56 mm as compared to K-SIR of 1.08 mm and RCS of 0.96 mm. Conclusion Both the intrusion rate and root resorption is more by utility arch while with K-SIR arch, though the rate of intrusion is almost same; the root resorption is much less. PMID:25737942

Goel, Prachi; Tandon, Ragni; Agrawal, Kaushal Kishor

2014-01-01

87

Neuroimaging: intrinsic lesions of the central skull base region.  

PubMed

The sphenoid bone is the osseous foundation of the central skull base. The body of the sphenoid is cuboid in shape and its posterior margin is joined to the basilar occipital bone (basiocciput) via a synchondrosis to form the complete clivus. Traditionally, radiologic discussions of intrinsic disease of the central skull base emphasize marrow space-occupying lesions including metastatic disease, myeloma, and chordoma. Based on our practical experience and the anatomical boundaries of the central skull-based region put forth, we include lesions of the sphenoid sinus and petrous apex in our discussion. We describe lesions that might originate within, be confined to, or principally involve the skeletal foundation of the central skull base, including the pneumatized regions contained within. Intrinsic lesions affecting the central skull base are emphasized and the most important computed tomography and magnetic resonance imaging findings that allow for effective diagnosis, planning, and treatment are highlighted. PMID:24216451

Bag, Asim K; Chapman, Philip R

2013-10-01

88

Characteristics of incisor-premolar hypodontia in families.  

PubMed

Nonsyndromic tooth agenesis is a genetically and phenotypically heterogenous condition. It is generally assumed that different phenotypic forms are caused by different mutated genes. We analyzed inheritance and phenotype of hypodontia and dental anomalies in 214 family members in three generations of 11 probands collected for genetic linkage study on incisor-premolar hypodontia (IPH). Our analysis confirms the autosomal-dominant transmission with reduced penetrance of IPH. The prevalence of hypodontia and/or peg-shaped teeth was over 40% in first- and second-degree relatives and 18% in first cousins of the probands. Four of nine noted obligate carriers of hypodontia gene had dental anomalies, including small upper lateral incisors, ectopic canines, taurodontism, and rotated premolars. These anomalies were also observed at higher than normal frequency in relatives affected with hypodontia. We conclude that incisor-premolar hypodontia is a genetic condition with autosomal-dominant transmission and that it is associated with several other dental abnormalities. PMID:11437217

Arte, S; Nieminen, P; Apajalahti, S; Haavikko, K; Thesleff, I; Pirinen, S

2001-05-01

89

Transposition of Mandibular Lateral Incisor–Canine (Mn.I2.C) Associated with Hypodontia: A Review and Rare Clinical Case  

PubMed Central

Transposition is a unique and extreme form of ectopic eruption in which a permanent tooth develops and erupts in the position which is normally occupied by other permanent teeth. Tooth transpositions are rare and they can be complete or incomplete. The aetiology of transposition is still obscure. Various populations have been studied, to determine the prevalence of tooth transpositions. 20% of the transpositions which occur on the maxillary arch involve the canine and the lateral incisor. Although they are rare, transpositions may involve the maxillary lateral and central incisors. Among all transpositions, Mandibular Lateral Incisor-Canine (Mn.I2.C) is the rarest, with a prevalence rate of 0.03%. Although various reports have been published on tooth transpositions, very few have noted the agenesis of teeth, particularly Mn.I2.C and its management. We are reporting a rare clinical case with associated hypodontia. PMID:24959525

Athimuthu, Anantharaj; Prasanna, Praveen; Jagadeesh, Ramya B

2014-01-01

90

Successful conservative treatment of dentigerous cyst following intrusion of lower primary incisors.  

PubMed

This paper reports on the development of a dentigerous cyst associated with a lower permanent incisor following intrusion of two lower primary incisors. The small root remnant of one of the traumatized primary incisors was associated with granulation tissue, while the second incisor was discolored and suspected of being non-vital. The associated permanent incisor and other adjacent incisors were apically and laterally dislocated from their natural site of eruption. The conservative treatment included extraction of the involved primary discolored incisor, as well as the root remnant, followed by removal of the granulation tissue. After 18 months of follow-up, the permanent incisors were erupting in normal position, without pathological signs of the dentigerous cyst. Following severe traumatic injury to a primary tooth, periodic radiographic follow-up, until eruption of the correspondent permanent tooth, is recommended. PMID:25672078

Ashkenazi, Malka; Levin, Liran

2014-01-01

91

Environmental seasonality and incremental growth rates of beaver ( Castor canadensis) incisors: implications for palaeobiology  

Microsoft Academic Search

Periradicular bands are incremental structures seen on the external dentin surfaces of rodent incisors. They correspond to circadian developmental rhythms in dentin growth and provide a record of the growth rate of the incisor along its longitudinal axis. In the present study, we investigate the relationship between daily environmental temperatures and longitudinal growth rates of incisors in 40 Recent beavers

Caroline Rinaldi; Theodore M. Cole

2004-01-01

92

Dental anomalies in the incisor-canine region in patients with cleft lip and palate - literature review.  

PubMed

Tooth disorders in the anterior region of the maxilla are very common among patients with cleft lip, alveolar bone and palate. The authors concentrate on dental disorders, erupting problems and root development, specifying dental anomalies - especially regarding the lateral incisor, central incisor and canine. Disorders may relate to the shape of the tooth, its location, size, number and they can be considered separately or together. Anomalies can be affected by many factors, such as orthodontic or surgical treatment, the presence of supernumerary teeth, lack of bone, genetic factors and many others. Each group of cleft is different and the following anomalies can be identified: UCLP (unilateral cleft lip and palate), BCLP (bilateral cleft lip and palate), UCLA (unilateral cleft lip and alveolus) and BCLA (bilateral cleft lip and alveolus). This article is intended to summarise some of the most recent knowledge about tooth disorders in the anterior region of cleft lip and palate patients and present them in an orderly way. PMID:25171623

Paradowska-Stolarz, Anna; Dubowik, Magdalena; Szel?g, Janina; Kawala, Beata

2014-01-01

93

Vascular lesions of the central skull base region.  

PubMed

The arterial and venous structures of the central skull base region form complex anatomical relationships with each other and with adjacent osseous and neural structures. Vascular structures including the cavernous sinuses and internal carotid arteries can be displaced, encased, or invaded by neoplastic, inflammatory, or infectious lesions of the central skull base. Consequently, the vascular structures have a unique role in determining the imaging appearance, clinical significance, and therapeutic options of lesions occurring in the central skull base. This article briefly reviews the basic anatomy of the cavernous sinus and the relationship of the internal carotid artery to the cavernous sinus and central skull base. The major imaging features of some common vascular lesions, including skull base aneurysm, carotid-cavernous fistula, and cavernous sinus thrombosis are presented. PMID:24216454

Chapman, Philip R; Gaddamanugu, Siddhartha; Bag, Asim K; Roth, Nathan T; Vattoth, Surjith

2013-10-01

94

Mouse Incisor Stem Cell Niche and Myb Transcription Factors.  

PubMed

Dental hard tissues are formed particularly by odontoblasts (dentin) and ameloblasts (enamel). Whereas the reparation of dentin is often observed, enamel does not regenerate in most species. However, in mouse incisor, a population of somatic stem cells in the cervical loop is responsible for the incisor regeneration. Understanding of the specificities of these cells is therefore of an interest in basic research as well as regenerative therapies. The Myb transcription factors are involved in essential cellular processes. B-Myb is often linked to the stem cell phenotype, and c-Myb expression marks undifferentiated and proliferating cells such as the stem cells. In the presented study, temporo-spatial expression of B-Myb and c-Myb proteins was correlated with localisation of putative somatic stem cells in the mouse incisor cervical loop by immunohistochemistry. B-Myb expression was localised mostly in the zone of transit-amplifying cells, and c-Myb was found in the inner enamel epithelium, the surrounding mesenchyme and in differentiated cells. Taken together, neither B-Myb nor c-Myb was exclusively present or abundant in the area of the incisor stem cell niche. Their distribution, however, supports recently reported novel functions of c-Myb in differentiation of hard tissue cells. PMID:25182175

Svandova, E; Vesela, B; Smarda, J; Hampl, A; Radlanski, R J; Matalova, E

2014-09-01

95

Continuous and Short Fiber Reinforced Composite in Root Post-Core System of Severely Damaged Incisors  

PubMed Central

Purpose: The aim of this study was to determine the static load-bearing capacity of endodontically treated maxillary incisors restored with post-core complex made of experimental fiber composite resin (FC) and complete crown made of particulate filler composite (PFC). Further aim was to evaluate the effect of FC resin on the failure mode of the restoration. Material and Methods: The experimental composite resin (FC) was prepared by mixing 22.5 wt% of short E-glass fibers (3 mm in length) and 22.5 wt% of semi-interpenetrating polymer network (IPN) resin with 55 wt% of silane treated silica fillers. Thirty extracted sound upper central incisors were used. Twenty teeth were prepared by cutting the clinical crown 2 mm above the cemento-enamel junction horizontally. Restorations were made by two techniques (n=10). Group A (control group) contained samples of sound incisor teeth. Group B had teeth restored using glass fiber post (everStick, Stick- Teck) and PFC (Filtek Z250, 3M-ESPE) to build up core and complete crown. In Group C, the teeth were restored with FC as post-core and complete crown of PFC. The root canals were prepared and posts were cemented with a dual cure resin cement. The restorations were polymerized with a hand-light curing unit. All restored teeth were stored in water at room temperature for 24 h before they were statically loaded with speed of 1.0 mm/min until fracture. Data were analyzed using ANOVA (p=0.05). Failure modes were visually examined. Results: ANOVA revealed that restored incisors (Group B and C) had a statistically significantly lower load-bearing capacity (p<0.05) than the control group. Restorations made from FC post-core and PFC coverage (Group C) gave force value of 363 N (112 SD), which was higher than the value of Group B (211 N, 50 SD). Conclusions: Within the limitations of this study, the teeth restored with experimental fiber composite post-core demonstrated higher load bearing capacity than those with fiber post and PFC core. PMID:19444342

Garoushi, Sufyan; Vallittu, Pekka K; Lassila, Lippo V.J

2009-01-01

96

Structure–function relations of primate lower incisors: a study of the deformation of Macaca mulatta dentition using electronic speckle pattern interferometry (ESPI)  

PubMed Central

Teeth adopt a variety of different morphologies, each of which is presumably optimized for performing specific functions during feeding. It is generally agreed that the enamel cap is a crucial element in controlling the mechanical behavior of mammalian teeth under load. Incisors are particularly interesting in terms of structure–function relations, as their role in feeding is that of the ‘first bite’. However, little is known how incisor cap morphology is related to tooth deformation. In the present paper we examine the mechanical behavior of mandibular central incisors in the cercopithecine primate Macaca mulatta under loads similar to those encountered during ingestion. We map three-dimensional displacements on the labial surface of the crown as it is compressed, using electronic speckle pattern interferometry (ESPI), an optical metrology method. In addition, micro-computed tomography is used to obtain data regarding the morphology of the enamel cap, which in the M. mulatta lower incisors exhibits missing or very little enamel on the lingual face. The results showed that although compressed along a longitudinal axis, deformation in the incisors mostly occurred in the lingual direction and orthogonal to the direction of the applied load. Both isolated, embedded teeth and teeth in the mandible showed considerable lingual deformation. Incisor deformation in the mandible was generally greater, reflecting the additional freedom of movement enabled by the supporting structures. We show that the association with adjacent teeth in the arch is significant for the behavior of the tooth under load. Finally, loading two teeth simultaneously in the mandible showed that they work as one functional unit. We suggest that these results demonstrate the importance of enamel cap morphology in directing deformation behavior; an ability stemming from the stiffness of the enamel cap overlying the more pliable dentin. PMID:20408905

Chattah, Netta Lev-Tov; Kupczik, Kornelius; Shahar, Ron; Hublin, Jean-Jacques; Weiner, Steve

2011-01-01

97

Structure-function relations of primate lower incisors: a study of the deformation of Macaca mulatta dentition using electronic speckle pattern interferometry (ESPI).  

PubMed

Teeth adopt a variety of different morphologies, each of which is presumably optimized for performing specific functions during feeding. It is generally agreed that the enamel cap is a crucial element in controlling the mechanical behavior of mammalian teeth under load. Incisors are particularly interesting in terms of structure-function relations, as their role in feeding is that of the 'first bite'. However, little is known how incisor cap morphology is related to tooth deformation. In the present paper we examine the mechanical behavior of mandibular central incisors in the cercopithecine primate Macaca mulatta under loads similar to those encountered during ingestion. We map three-dimensional displacements on the labial surface of the crown as it is compressed, using electronic speckle pattern interferometry (ESPI), an optical metrology method. In addition, micro-computed tomography is used to obtain data regarding the morphology of the enamel cap, which in the M. mulatta lower incisors exhibits missing or very little enamel on the lingual face. The results showed that although compressed along a longitudinal axis, deformation in the incisors mostly occurred in the lingual direction and orthogonal to the direction of the applied load. Both isolated, embedded teeth and teeth in the mandible showed considerable lingual deformation. Incisor deformation in the mandible was generally greater, reflecting the additional freedom of movement enabled by the supporting structures. We show that the association with adjacent teeth in the arch is significant for the behavior of the tooth under load. Finally, loading two teeth simultaneously in the mandible showed that they work as one functional unit. We suggest that these results demonstrate the importance of enamel cap morphology in directing deformation behavior; an ability stemming from the stiffness of the enamel cap overlying the more pliable dentin. PMID:20408905

Chattah, Netta Lev-Tov; Kupczik, Kornelius; Shahar, Ron; Hublin, Jean-Jacques; Weiner, Steve

2011-01-01

98

Finite element analysis of equine incisor teeth. Part 2: investigation of stresses and strain energy densities in the periodontal ligament and surrounding bone during tooth movement.  

PubMed

This study investigated the hypothetical contribution of biomechanical loading to the onset of equine odontoclastic tooth resorption and hypercementosis (EOTRH) and to elucidate the physiological age-related positional changes of the equine incisors. Based on high resolution micro-computed tomography (?CT) datasets, 3-dimensional models of entire incisor arcades and the canine teeth were constructed representing a young and an old incisor dentition. Special attention was paid to constructing an anatomically correct model of the periodontal ligament (PDL). Using previously determined Young's moduli for the equine incisor PDL, finite element (FE) analysis was performed. Resulting strains, stresses and strain energy densities (SEDs), as well as the resulting regions of tension and compression within the PDL and the surrounding bone were investigated during occlusion. The results showed a distinct distribution pattern of high stresses and corresponding SEDs in the PDL and bone. Due to the tooth movement, peaks of SEDs were obtained in the PDL as well as in the bone on the labial and palatal/lingual sides of the alveolar crest. At the root, highest SEDs were detected in the PDL on the palatal/lingual side slightly occlusal of the root tip. This distribution pattern of high SEDs within the PDL coincides with the position of initial resorptive lesions in EOTRH affected teeth. The position of high SEDs in the bone can explain the typical age-related alteration of shape and angulation of equine incisors. PMID:24252223

Schrock, P; Lüpke, M; Seifert, H; Staszyk, C

2013-12-01

99

A Rare Occurrence of Geminated-Taloned Maxillary Lateral Incisor  

PubMed Central

ABSTRACT The talon cusp is a developmental anomaly characterized by the presence of an accessory cusp like structure projecting from the cingulum area of the anterior teeth. Gemination is an anomaly caused by a single tooth germ that attempted to divide during its development. These developmental anomalies may cause clinical problems including esthetic impairment, pain, caries and tooth crowding. Co-occurrence of two anomalies in a teeth is rare. This paper presents an unusual case of talon cusp on geminated permanent lateral incisor. How to cite this article: Neeraja R, Kayal VG. A Rare Occurrence of Geminated-Taloned Maxillary Lateral Incisor. Int J Clin Pediatr Dent 2012;5(2):136-138. PMID:25206153

Kayal, Vizhi G

2012-01-01

100

A rare occurrence of geminated-taloned maxillary lateral incisor.  

PubMed

The talon cusp is a developmental anomaly characterized by the presence of an accessory cusp like structure projecting from the cingulum area of the anterior teeth. Gemination is an anomaly caused by a single tooth germ that attempted to divide during its development. These developmental anomalies may cause clinical problems including esthetic impairment, pain, caries and tooth crowding. Co-occurrence of two anomalies in a teeth is rare. This paper presents an unusual case of talon cusp on geminated permanent lateral incisor. How to cite this article: Neeraja R, Kayal VG. A Rare Occurrence of Geminated-Taloned Maxillary Lateral Incisor. Int J Clin Pediatr Dent 2012;5(2):136-138. PMID:25206153

Neeraja, R; Kayal, Vizhi G

2012-05-01

101

Oxygen distribution and consumption in rat lower incisor pulp  

Microsoft Academic Search

The aim was to determine the oxygen tension (PO2) and rate of oxygen consumption in the pulp. Twelve rats were anaesthetised and artificially ventilated. Under an operating microscope, a recessed oxygen-sensitive microelectrode was inserted into the pulp through a small saline-covered cavity on the labial surface of the lower incisor. PO2 was measured as a function of the transverse distance

C. Y Yu; N. M Boyd; S. J Cringle; V. A Alder; D. Y Yu

2002-01-01

102

Network Generation Model by Rational Agent based on Centrality  

NASA Astrophysics Data System (ADS)

Scale-free and small-world networks receive much attention recently, that are revealed to exist in many natural and artificial systems. There have been several studies on how such networks emerge. In this paper, we propose a novel approach to explain the emergence of different network structures through multi-agent network simulation. Each agent, which represents a node, has rationality and edges to be added are chosen based on mutual common consent. An agent tries to increase its own centrality in the network, and it votes so that its centrality is maximized. Depending on the types of centrality measures, different types of network structures are obtained. This model of network evolution explains emergence of a network where many agents participate in creating it: It includes a social network where each person tries to be more central, and traffic network where each region tries to be more accessible.

Matsuo, Yutaka; Shinoda, Kosuke; Nakashima, Hideyuki

103

BCL11B Regulates Epithelial Proliferation and Asymmetric Development of the Mouse Mandibular Incisor  

PubMed Central

Mouse incisors grow continuously throughout life with enamel deposition uniquely on the outer, or labial, side of the tooth. Asymmetric enamel deposition is due to the presence of enamel-secreting ameloblasts exclusively within the labial epithelium of the incisor. We have previously shown that mice lacking the transcription factor BCL11B/CTIP2 (BCL11B hereafter) exhibit severely disrupted ameloblast formation in the developing incisor. We now report that BCL11B is a key factor controlling epithelial proliferation and overall developmental asymmetry of the mouse incisor: BCL11B is necessary for proliferation of the labial epithelium and development of the epithelial stem cell niche, which gives rise to ameloblasts; conversely, BCL11B suppresses epithelial proliferation, and development of stem cells and ameloblasts on the inner, or lingual, side of the incisor. This bidirectional action of BCL11B in the incisor epithelia appears responsible for the asymmetry of ameloblast localization in developing incisor. Underlying these spatio-specific functions of BCL11B in incisor development is the regulation of a large gene network comprised of genes encoding several members of the FGF and TGF? superfamilies, Sprouty proteins, and Sonic hedgehog. Our data integrate BCL11B into these pathways during incisor development and reveal the molecular mechanisms that underlie phenotypes of both Bcl11b?/? and Sprouty mutant mice. PMID:22629441

Kyrylkova, Kateryna; Kyryachenko, Sergiy; Biehs, Brian; Klein, Ophir; Kioussi, Chrissa; Leid, Mark

2012-01-01

104

Radiographic Investigation of Frequency and Degree of Canal Curvatures in Chinese Mandibular Permanent Incisors  

Microsoft Academic Search

Accurate knowledge of root canal curvature is a critical factor in successful root canal procedures. The objective of this study was to determine the degree of root canal curvature and the frequency of curvature identified in different radiographic views in permanent incisors from a Chinese population. The curvature of canals from 299 permanent mandibular incisors was investigated by measuring the

Qing-hua Zheng; Xue-dong Zhou; Ying Jiang; Tuo-qi Sun; Cheng-xia Liu; Hui Xue; Ding-ming Huang

2009-01-01

105

Restoring the vertical dimension of mandibular incisors with bonded ceramic restorations  

Microsoft Academic Search

Mandibular incisors are difficult to restore with conventional anterior crowns due to their small axial diameters. Crown preparation risks pulp exposure and results in a thin core of dentine. An experiment was designed to determine if increasing the thickness of ceramic to restore incisal edges affects the load at the point of restoration failure. Forty-eight mandibular incisors were randomly divided

S. G. Wylie; H. K. Tan; K. Brooke

2000-01-01

106

The Clinical and Radiographic Success of Bonded Resin Composite Strip Crowns for Primary Incisors  

Microsoft Academic Search

Purpose: The aim of this study was to examine the clinical and radiographic success of the treatment of maxillary anterior primary incisors with composite resin strip crowns placed in a private practice setting. Methods: This was a retrospective, clinical study of patients who had strip crowns (SC) placed on maxillary primary incisors, returned for at least 1, 6-month recall examina-

Ari Kupietzky; William F. Waggoner; Jon Galea

2003-01-01

107

A Study of Central Auction Based Wholesale Electricity Markets  

NASA Astrophysics Data System (ADS)

The deregulation of electricity markets produced significant economic benefits, reducing prices to customers and opening several opportunities for new actors, e.g., new generators and distributors. A prominent scientific and technological challenge is the automation of such markets. In particular, we focus our attention on wholesale electricity markets based on a central auction. In these markets, generators sell electricity by means of a central auction to a public authority. Instead, the distribution of electricity to customers takes part in retail markets. The main works presented in the literature model wholesale markets as oligopolies, neglecting thus the specific auction mechanism. In this paper, we enrich these models by introducing an auction mechanism shaped on that used in the Italian wholesale electricity market, we solve the winner determination problem, and we preliminarily study the problem of searching for equilibria.

Ceppi, Sofia; Gatti, Nicola

108

Advances in the treatment of diseased equine incisor and canine teeth.  

PubMed

Dental therapies for equid incisor and canine teeth have modernized significantly over the last 2 decades. Basic principles in incisor reduction have become more conservative, and extraction procedures more exacting. Periodontal and endodontic treatments are described to save teeth that would have succumbed to extraction in the past. Pathologic impacts on treatment decisions for equine odontoclastic tooth resorption and hypercementosis are significant, and veterinarians and owners need to be aware of treatment options and outcomes. Easy access to equid incisor and canine teeth offers a variety of therapeutic options, and this article reviews some of the practical procedures available. PMID:23915667

Rawlinson, Jennifer T; Earley, Edward

2013-08-01

109

A new understanding of oral and dental disorders of the equine incisor and canine teeth.  

PubMed

This article discusses the classification systems for dental fractures and how the assessment affects treatment options. Diagonal incisor malocclusion is discussed in relation to skull asymmetry and how this commonly relates to premolar and molar occlusion. Oral and radiographic assessment of incisive bone fracture and incisor avulsion is reviewed for determining treatment options. A summary of incisor and canine resorption and hypercementosis is presented. Clinical presentations, staging, and classifications of tooth resorption as well as canine odontoplasty are discussed. Excessive plaque and calculus formation on lower canines leading to periodontal disease and abscess is examined. PMID:23915661

Earley, Edward; Rawlinson, Jennifer T

2013-08-01

110

Notching and anterior beveling on fossil horse incisors: Indicators of domestication?  

NASA Astrophysics Data System (ADS)

One of the lines of evidence cited for possible late Pleistocene human control of horses has been the presence of notching and anterior beveling on horse incisor teeth recovered from upper and middle Paleolithic sites in Europe. Similar forms of wear have been found on the incisor teeth of wild horses from early and middle Pleistocene deposits in North America. Notching appears partly due to malocclusion and chipping. The causes of beveling are less certain but may involve the eating of bark. Therefore, the presence of notching and anterior beveling on horse incisor teeth may not be a reliable indicator of human control.

Rogers, Richard A.; Rogers, Laurine A.

1988-01-01

111

Crown and root lengths of incisors, canines, and premolars measured by cone-beam computed tomography in patients with malocclusions  

PubMed Central

Objective The purposes of this study were to determine the accuracy of crown and root length measurements of premolars using cone-beam computed tomography (CBCT) and to generate reference CBCT-based data on incisor, canine, and premolar lengths in patients with malocclusions. Methods Imaging was performed using a CBCT scanner with a 0.292-mm voxel size and 12-bit grayscale. The CBCT-based length measurements were compared with direct measurements of 94 subsequently extracted premolars without metal restorations using the paired t-test. Furthermore, the crown and root lengths of incisors, canines, and premolars in 62 Korean patients with malocclusions were measured using CBCT, and Pearson's correlation coefficients were calculated to examine the relationship between the crown and root length measurements of each tooth type. Results The differences between the CBCT-based and direct measurements of the extracted premolars were not significant, with 95% limits of agreement of -0.90 to 0.90 mm for crown length and -1.23 to 1.18 mm for root length. Weak positive correlations between the crown and root length measurements were observed for the mandibular canine and premolars. Conclusions The CBCT-based measurements showed a wider range of limits of agreements for root length than for crown length. The CBCT-based data can be used as a reference for evaluating root length and resorption of teeth without metal restorations in patients with malocclusions. PMID:24396736

Kim, Seon-Young; Gang, Sung-Nam; Kim, Hee-Jin

2013-01-01

112

Dimensional changes in height of labial alveolar bone of proclined lower incisor after lingual positioning by orthodontic treatment: A cephalometric study on adult Bengali population  

PubMed Central

Aim: The study aims to know whether modern orthodontic treatment procedure do actually cause permanent bone loss at the alveolar bone crest or improve alveolar bone morphology on labial aspect of permanent incisors which are to be moved lingually. Settings and Design: Manual tracings of pre and post treatment lateral cephalometric radiographs were used. Material and Method: The cephalometric radiographs of 34 adult bengali subjects whose orthodontic treatment involved lingual positioning of procumbent mandibular central incisors were examined to determine the morphologic changes (bone height) in the labial alveolar bone that resulted from orthodontic treatment. Result: Comparison of tracings of radiographs taken before and after treatment indicated that 57.6% shows an increase in labial alveolar bone height, 30.3% shows decreased value and 12.1% shows no change with the decrease in the angulation between long axis of lower incisor and mandibular plane (GoGn). In the increase group there is a significant increase in the distance ‘incisal edge to D point’ whereas this dimension decreased significantly in the rest of the cases. In addition, a significant positive correlation (r = 0.56) was found between the changes in the distance from the incisal edge to the ‘D’ point and the alveolar bone height. But no significant relation was found between alveolar bone height and decrease in angulation of lower incisor either in the ‘increase group’ (r = 0.13, p > 0.05) or in the ‘decrease group’ (r = 0.37, p > 0.05). Conclusion: These findings indicate that during orthodontic treatment that involves lingual positioning of procumbent teeth but no intrusion, an increase in the amount of buccal alveolar bone may take place. PMID:25684908

Shaw, Amit

2015-01-01

113

Gingival labial recessions and the post-treatment proclination of mandibular incisors.  

PubMed

Summary INTRODUCTION : A prerequisite for development of gingival recession is the presence of alveolar bone dehiscence. Proclination of mandibular incisors can result in thinning of the alveolus and dehiscence formation. PMID:25481921

Renkema, Anne-Marie; Navratilova, Zuzanna; Mazurova, Katerina; Katsaros, Christos; Fudalej, Piotr S

2014-12-01

114

Treatment of Two Canals in All Mandibular Incisor Teeth in the Same Patient  

PubMed Central

The main reason for unfavourable outcome in endodontic treatment of mandibular incisor is the inability to detect the presence of second canal. Pain even after extirpation of complete pulp tissue from root canal of vital teeth is the main indication of hidden canals. The present case report is also on pain because of another neglected canal in all mandibular incisors in the same patient. PMID:25478246

Kokane, Vandana B.; Patil, Swapnil N.; Gunwal, Mohit K.; Kubde, Rajesh; Atre, Swaraj

2014-01-01

115

Comparisons of nipple attachment and incisor growth among four species of voles (Microtus).  

PubMed

Patterns of nipple attachment and incisor growth were compared between four species of voles (Microtus). Offspring of two highly social species, prairie voles (M. ochrogaster) and pine voles (M. pinetorum), were shown to cling tightly to the nipples of their dams on Days 2, 6, and 10. This pattern contrasted to weak nipple attachment displayed by two less-social species, meadow voles (M. pennsylvanicus) and montane voles (M. montanus). Lengths of the upper (maxillary) and lower (mandibular) incisors of the four species were recorded throughout the first 10 days of age and in adults. Incisors of the pine and prairie voles typically erupted earlier and grew longer than those of the meadow or montane voles during the first few days of development. Incisors grew at a substantial rate in the latter two species, such that they equalled or surpassed the incisor lengths of the former two species as Day 10 and weaning approached. Patterns of incisor growth, in part, reflected those for nipple attachment, but do not appear to account substantially for differences in nipple attachment. PMID:7926283

Salo, A L; Shapiro, L E; Dewsbury, D A

1994-07-01

116

Post-traumatic treatment of maxillary incisors by immediate dentoalveolar restoration with long-term follow-up.  

PubMed

Replacing both missing maxillary anterior teeth is particularly challenging, especially in compromised sockets. This case report describes the management of an 18-year-old female patient, who suffered avulsion of both maxillary central incisors at 7 years of age. This multidisciplinary implant technique, called Immediate Dentoalveolar Restoration (IDR), included extraction of the injured teeth and a single procedure for immediate implant placement and restoration of the compromised sockets after root fracture and periapical lesion development were detected during orthodontic treatment. Successful esthetic and functional outcomes and reestablishment of the alveolar process after bone reconstruction were observed during the 3-year follow-up period. The predictable esthetic outcomes and soft- and hard-tissue stability that can be achieved following IDR are demonstrated. PMID:25822639

Rosa, Ariádene Cristina Pértile de Oliveira; Francischone, Carlos Eduardo; Cardoso, Mauricio de Almeida; Alonso, Ana Carolina; Filho, Leopoldino Capelozza; da Rosa, José Carlos Martins

2015-02-01

117

Surgical Treatment of an Immature Short-Rooted Traumatized Incisor with an Extensive Apical Lesion Using CEM Cement  

PubMed Central

Severe traumatic injuries to immature teeth often cause damage to periodontal ligament as well as dental pulp; pulp necrosis, root resorption and subsequent apical lesion are common consequences. This article reports the surgical management of an infected immature maxillary central incisor associated with a gigantic periradicular lesion and severe root resorption. The tooth had a history of trauma and the patient suffered from purulent sinus tract and tooth mobility. After unsuccessful multi-session disinfection with calcium hydroxide, root end surgery was planned. During flap surgery and lesion enucleation, the root end was cleaned and filled with calcium-enriched mixture (CEM) cement. After one year, the radiographic examination revealed that the lesion was almost completely replaced with newly formed bone. In addition, clinical examination showed favorable outcomes; the tooth was symptom-free and in function. Due to chemical, physical and biological properties of CEM cement, this biomaterial might be considered as the root-end filling material of choice.

Asgary, Saeed; Fazlyab, Mahta

2015-01-01

118

Lateral incisor agenesis, canine impaction and characteristics of supernumerary teeth in a South European male population  

PubMed Central

Objective: To assess the prevalence of lateral incisor agenesis impacted canines and supernumerary teeth in a young adult male population. Materials and Methods: The panoramic radiographs of 1745 military students (mean age: 18.6 ± 0.52 years) who attended the Center of Aviation Medicine of the Armed Forces of Greece during the period 1997-2011 were initially analyzed for lateral incisor agenesis by two observers. After exclusion of the known orthodontic cases, a subgroup of 1636 examinees (mean age: 18.6 ± 0.44 years) was evaluated for canine impaction and supernumerary teeth. Results: Twenty-eight missing lateral incisors were observed in 22 military students, indicating an incidence of 1.3% in the investigated population. No lateral incisor agenesis was detected in the mandibular arch. A prevalence rate of 0.8% was determined for canine impaction in the sample of young adults. The majority of impacted teeth (86.7%) were diagnosed in the maxillary arch. Thirty-five supernumerary teeth were observed in 24 examinees (prevalence rate: 1.5%). The ratio of supernumerary teeth located in the maxilla versus the mandible was 2.2:1. The most common type of supernumerary tooth was the upper distomolar. Conclusion: The prevalence of lateral incisor agenesis, canine impaction, and supernumerary teeth ranged from 0.8 to 1.5% in the sample of male Greek military students. PMID:24926206

Delli, Konstantina; Livas, Christos; Bornstein, Michael M.

2013-01-01

119

Changes of anterior maxillary alveolar bone thickness following incisor proclination and extrusion.  

PubMed

Objective: To investigate changes in maxillary alveolar bone thickness after maxillary incisor proclination and extrusion during anterior crossbite correction in a group of growing patients with Class III malocclusion. Materials and Methods: Maxillary incisors of 15 growing patients with anterior crossbite were proclined and extruded with 0.016? beta-titanium advancing loops and Class III elastics. Lateral cephalograms were recorded before advancement (T0) and 4 months after a normal overjet and overbite were achieved (T1). Changes in alveolar bone thickness surrounding the maxillary incisors at the crestal (S1), midroot (S2), and apical (S3) levels were measured using cone-beam computed tomography (CBCT). Paired t-tests were used to determine the significance of the changes. A Spearman rank correlation analysis was performed to explore the relationship between thickness changes and the rate and amount of incisor movements. Results: Although statistically significant decreases were observed in palatal and total bone thickness at the S2 and S3 level (P < .05), the amounts of these changes were clinically insignificant, ranging from 0.34 to 0.59 mm. Changes in labial bone thickness at all levels were not significant. Changes in palatal bone thickness at S3 were negatively correlated with changes in incisor inclination. (r ?=? -0.71; P < .05). Conclusion: In a group of growing patients with Class III malocclusion undergoing anterior crossbite correction, controlled tipping mechanics accompanied by extrusive force may produce successful tooth movement with minimal iatrogenic detriment to the alveolar bone. PMID:25208232

Thongudomporn, Udom; Charoemratrote, Chairat; Jearapongpakorn, Sarayut

2014-09-10

120

Embrasure morphology and central papilla recession  

PubMed Central

Background: The aim of this study was to ascertain the effects of vertical and horizontal distances between the maxillary central incisors on the presence of interproximal dental papilla and to assess the association between the embrasure morphology and central papilla recession. Materials and Methods: The central papilla was visually assessed in 50 subjects using the standardized periapical radiographs of maxillary central incisors. The following vertical distances were measured; distance from the contact point to papilla tip, CP to proximal cementoenamel (pCEJ) junction, bone crest to CP (BC-CP) and BC-PT. The horizontal distance measured was interdental width (IDW) at pCEJ level. The measurements were recorded using a digital electronic caliper. Results: Significant association between the embrasure morphology and central papilla recession was observed for all study groups. All the interdental variables were significantly related to the presence of interdental papillae, with BC-CP distance being the strongest determinant of central papilla presence. The percentage of interdental papilla presence was 100% when the BC-CP distance was ?6 mm and IDW ranged between 0.5 and 1.5 mm. Central papilla recession was observed most frequently with wide-long and narrow-long embrasure morphology. Conclusion: In relation to maxillary central incisors, all the interdental variables have significant influences on the presence of interdental papillae, with distance from BC to CP being the strongest determinant of central papilla presence. PMID:24872628

Saxena, Divya; Kapoor, Anoop; Malhotra, Ranjan; Grover, Vishakha

2014-01-01

121

Neurogenic potential of dental pulp stem cells isolated from murine incisors  

PubMed Central

Introduction Interest in the use of dental pulp stem cells (DPSC) to enhance neurological recovery following stroke and traumatic injury is increasing following successful pre-clinical studies. A murine model of autologous neural stem cell transplantation would be useful for further pre-clinical investigation of the underlying mechanisms. However, while human-derived DPSC have been well characterised, the neurogenic potential of murine DPSC (mDPSC) has been largely neglected. In this study we demonstrate neuronal differentiation of DPSC from murine incisors in vitro. Methods mDPSC were cultured under neuroinductive conditions and assessed for neuronal and glial markers and electrophysiological functional maturation. Results mDPSC developed a neuronal morphology and high expression of neural markers nestin, ßIII-tubulin and GFAP. Neurofilament M and S100 were found in lower abundance. Differentiated cells also expressed protein markers for cholinergic, GABAergic and glutaminergic neurons, indicating a mixture of central and peripheral nervous system cell types. Intracellular electrophysiological analysis revealed the presence of voltage-gated L-type Ca2+ channels in a majority of cells with neuronal morphology. No voltage-gated Na+ or K+ currents were found and the cultures did not support spontaneous action potentials. Neuronal-like networks expressed the gap junction protein, connexin 43 but this was not associated with dye coupling between adjacent cells after injection of the low-molecular weight tracers Lucifer yellow or Neurobiotin. This indicated that the connexin proteins were not forming traditional gap junction channels. Conclusions The data presented support the differentiation of mDPSC into immature neuronal-like networks. PMID:24572146

2014-01-01

122

Gemination of a permanent lateral incisor- a case report with special emphasis on management.  

PubMed

The purpose of this case report is to describe the successful endodontic treatment and surgical management of a unesthetic geminated permanent maxillary lateral incisor tooth. Geminated maxillary incisor clinically revealed bifid crown with coronal groove and intraoral periapical radiograph showing radiolucent lesion with sclerotic border. orthograde root canal treatment was performed. surgery was done by reflecting limited thickness mucoperiosteal flap, cyst enucleated, root end resected and retrograde filling done using mineral trioxide aggregate. During the follow up examination, post operative intra oral periapical radiographs revealed healing of periapical lesion. Key words:Gemination, Periapical Cyst, Retrograde Filling. How to cite this article: Sharada H L, Deo B, Briget B. Gemination of a Permanent Lateral Incisor - A Case Report with Special Emphasis on Management. J Int Oral Health 2013; 5(2):55-59. PMID:24155591

Sharada, H L; Deo, Bharathi; Briget, Biji

2013-04-01

123

Reactive Robot Navigation Based on a Combination of Central and Peripheral Vision  

E-print Network

Reactive Robot Navigation Based on a Combination of Central and Peripheral Vision Abstract In this paper, we present a new method for vision-based, reactive robot navigation that enables a robot to move in the middle of the free space by exploiting both central and peripheral vision. The system employs a forward

Trahanias, Panos

124

A Retrospective Assessment of Zinc Oxide-Eugenol Pulpectomies in Vital Maxillary Primary Incisors Successfully Restored With Composite Resin Crowns  

Microsoft Academic Search

Purpose: The purpose of this retrospective study was to evaluate, via clinical and radio- graphic assessments, the treatment outcome of zinc oxide-eugenol (ZOE) pulpectomies performed in vital maxillary primary incisors successfully restored with composite resin crowns. Methods: Pulpectomized vital primary incisors were treated by a uniformed technique, filled with ZOE paste, and successfully restored with composite resin crowns. Those that

Robert E. Primosch; Anissa Ahmadi; Barry Setzer

2005-01-01

125

A camouflage treatment of Class II division 1 malocclusion complicated by missing lateral incisor.  

PubMed

This case report describes the treatment of a male patient, aged 16 years and 5 months, with a Class II division 1 malocclusion, who showed severe anterior protrusion and lower anterior crowding along with missing upper left lateral incisor. Treatment plan consisted of extraction of upper right first premolar and lower second premolars. No extraction was performed on the upper left quadrant instead canine was substituted as lateral incisor and premolar as canine to establish a good occlusion. Power arms were used for intrusion and retraction of the anterior teeth. After active treatment period of 21 months, the appliances were removed after establishing ideal overjet, overbite and other occlusal relationships. PMID:25745709

Venkatesh, Shivanand; Ganeshkar, Sanjay V; Rozario, Joe

2014-01-01

126

New fault tolerant robotic central controller for space robot system based on ARM processor  

Microsoft Academic Search

A new fault tolerant robotic central controller with dual processing modules is introduced. Each processing module is composed of 32 bit ARM RISC processor and other commercial-off-the-shelf (COTS) devices. As well as, a set of fault handling mechanisms is implemented in the robotic central controller, which can tolerate a single fault. The robotic central controller software based on VxWorks is

Xinsheng Wang; Bin Liang; Ruilan Wu

2008-01-01

127

Isolation and culture of dental epithelial stem cells from the adult mouse incisor.  

PubMed

Understanding the cellular and molecular mechanisms that underlie tooth regeneration and renewal has become a topic of great interest(1-4), and the mouse incisor provides a model for these processes. This remarkable organ grows continuously throughout the animal's life and generates all the necessary cell types from active pools of adult stem cells housed in the labial (toward the lip) and lingual (toward the tongue) cervical loop (CL) regions. Only the dental stem cells from the labial CL give rise to ameloblasts that generate enamel, the outer covering of teeth, on the labial surface. This asymmetric enamel formation allows abrasion at the incisor tip, and progenitors and stem cells in the proximal incisor ensure that the dental tissues are constantly replenished. The ability to isolate and grow these progenitor or stem cells in vitro allows their expansion and opens doors to numerous experiments not achievable in vivo, such as high throughput testing of potential stem cell regulatory factors. Here, we describe and demonstrate a reliable and consistent method to culture cells from the labial CL of the mouse incisor. PMID:24834972

Chavez, Miquella G; Hu, Jimmy; Seidel, Kerstin; Li, Chunying; Jheon, Andrew; Naveau, Adrien; Horst, Orapin; Klein, Ophir D

2014-01-01

128

A Teething Problem: Artefactual X-Ray Appearances of Odontoid Fracture due to Superimposed Incisor  

PubMed Central

We report a case of artefactual C2 fracture caused by a superimposed incisor tooth in a seven-year-old boy. CT refuted the diagnosis. Trauma clinicians should be aware of this entity to guide correct interpretation of trauma X-rays. PMID:23326716

Crocker, Matthew; Crocker, Maeve E.

2012-01-01

129

An Evolutionarily Conserved Enhancer Regulates Bmp4 Expression in Developing Incisor and Limb Bud  

PubMed Central

To elucidate the transcriptional regulation of Bmp4 expression during organogenesis, we used phylogenetic footprinting and transgenic reporter analyses to identify Bmp4 cis-regulatory modules (CRMs). These analyses identified a regulatory region located ?46 kb upstream of the mouse Bmp4 transcription start site that had previously been shown to direct expression in lateral plate mesoderm. We refined this regulatory region to a 396-bp minimal enhancer, and show that it recapitulates features of endogenous Bmp4 expression in developing mandibular arch ectoderm and incisor epithelium during the initiation-stage of tooth development. In addition, this enhancer directs expression in the apical ectodermal ridge (AER) of the developing limb and in anterior and posterior limb mesenchyme. Transcript profiling of E11.5 mouse incisor dental lamina, together with protein binding microarray (PBM) analyses, allowed identification of a conserved DNA binding motif in the Bmp4 enhancer for Pitx homeoproteins, which are also expressed in the developing mandibular and incisor epithelium. In vitro electrophoretic mobility shift assays (EMSA) and in vivo transgenic reporter mutational analyses revealed that this site supports Pitx binding and that the site is necessary to recapitulate aspects of endogenous Bmp4 expression in developing craniofacial and limb tissues. Finally, Pitx2 chromatin immunoprecipitation (ChIP) demonstrated direct binding of Pitx2 to this Bmp4 enhancer site in a dental epithelial cell line. These results establish a direct molecular regulatory link between Pitx family members and Bmp4 gene expression in developing incisor epithelium. PMID:22701669

O’Connell, Daniel J.; Aboukhalil, Anton; Li, Xiao; Choe, Sung E.; Ho, Joshua W. K.; Turbe-Doan, Annick; Robertson, Erin A.; Olsen, Bjorn R.; Bulyk, Martha L.; Amendt, Brad A.; Maas, Richard L.

2012-01-01

130

A ceramic restoration bonded by etched enamel and resin for fractured incisors.  

PubMed

This report describes a technique for making ceramic restorations for fractured incisors without operative interference. The ceramic block is baked in the laboratory on a 24 karat gold matrix cast. A resin is bonded to a silane-treated porcelain block and etched enamel. PMID:1089784

Rochette, A L

1975-03-01

131

Qualitative electron probe analysis of secretory ameloblasts and odontoblasts in the rat incisor  

Microsoft Academic Search

Rapidly frozen growing rat incisors were freeze fractured and freeze dried in preparation for energy dispersive X-ray emission microanalysis in a scanning electron microscope. Ca levels were found to be elevated in the distal cell body of odontoblasts, whereas Ca was uniformly low over all parts of the cell body of secretory ameloblasts. The results suggest fundamental differences in the

A. Boyde; E. J. Reith

1977-01-01

132

Ultrastructural localisation of proteoglycans in the odontoblast-predentin region of rat incisor  

Microsoft Academic Search

The localization of proteoglycans in the predentin of the rat incisor was investigated by ultrastructural histochemistry. Ruthenium red stained the cell coat of the odontoblasts as well as intracellular vesicles. There was also a staining of the extracellular matrix, but not of collagen fibers in the predentin. Treatment with the enzyme hyaluronidase prior to staining with ruthenium red abolished the

H. Nygren; H. A. Hansson; A. Linde

1976-01-01

133

Prevalence and Incidence of Gemination and Fusion in Maxillary Lateral Incisors in Odisha population and Related Case Report  

PubMed Central

Aim: A survey was conducted to analyze the prevalence and incidence of dental anomalies in relation to maxillary lateral incisors in the Odisha population. A multidisciplinary approach for aesthetic management of a geminated tooth is described. Material and Methods: A total of 1062 subject, aged between 15-30 years (724 males and 338 Females) were randomly screened at Institute of Dental Sciences, Bhubaneswar, Odisha India. Each subject was examined clinically and radiovisuographically for dental anomalies in relation to maxillary lateral incisors. In the related case described, endodontic management and aesthetic correction of geminated maxillary lateral incisors was done. Results: Five dental anomalies i.e. gemination, fusion, missing lateral incisors (both unilateral and bilateral), peg shaped incisors (unilateral and bilateral), and dens in dente were observed. Anomalies found were Peg shaped; 2.82%, Missing;1.88%, Gemination;0.28%, Fusion;0.18% and Dens in Dente;0.18%. Conclusion: Comparison of these results with that of other studies indicated that anomalies in lateral incisors occur at different frequencies among various countries and communities in the world. In the case since maxillary lateral incisors are in the aesthetic zone, recognizing these anomalies will facilitate a successful treatment. PMID:24298521

G., Shashirekha; Jena, Amit

2013-01-01

134

Centralizing Data Management with Considerations of Uncertainty and Information-Based Flexibility  

E-print Network

This paper applies the theory of real options to analyze how the value of information-based flexibility should affect the decision to centralize or decentralize data management under low and high uncertainty. This study ...

Velu, Chander K.

135

Sins Invalid is a disability justice based performance project of artists with disabilities, centralizing artists of  

E-print Network

Sins Invalid is a disability justice based performance project of artists with disabilities, centralizing artists of color and queer and gender-variant artists. Since 2006, its performances have explored

He, Chuan

136

An efficient community detection method based on rank centrality  

NASA Astrophysics Data System (ADS)

Community detection is a very important problem in social network analysis. Classical clustering approach, K-means, has been shown to be very efficient to detect communities in networks. However, K-means is quite sensitive to the initial centroids or seeds, especially when it is used to detect communities. To solve this problem, in this study, we propose an efficient algorithm K-rank, which selects the top-K nodes with the highest rank centrality as the initial seeds, and updates these seeds by using an iterative technique like K-means. Then we extend K-rank to partition directed, weighted networks, and to detect overlapping communities. The empirical study on synthetic and real networks show that K-rank is robust and better than the state-of-the-art algorithms including K-means, BGLL, LPA, infomap and OSLOM.

Jiang, Yawen; Jia, Caiyan; Yu, Jian

2013-05-01

137

From pyridinium-based to centrally active acetylcholinesterase reactivators.  

PubMed

Organophosphates are used as pesticides or misused as warfare nerve agents. Exposure to them can be fatal and death is usually caused by respiratory arrest. For almost six decades, pyridinium oximes represent a therapeutic tool used for the management of poisoning with organophosphorus (OP) compounds. However, these compounds possess several drawbacks. Firstly, they are inefficient in the restoration of brain acetylcholinesterase (AChE) activity due to a hard blood-brain barrier penetration. Secondly, there is no broad-spectrum AChE reactivator. Lastly, none of the oximes can reactivate "aged" AChE. In this context, uncharged reactivators represent a new hope in a way of increased bioavailability in the central compartment and better therapeutic management of the OP poisoning. PMID:24552265

Korabecny, Jan; Soukup, Ondrej; Dolezal, Rafael; Spilovska, Katarina; Nepovimova, Eugenie; Andrs, Martin; Nguyen, Thuy Duong; Jun, Daniel; Musilek, Kamil; Kucerova-Chlupacova, Marta; Kuca, Kamil

2014-01-01

138

Equine dental disease part 1: a long-term study of 400 cases: disorders of incisor, canine and first premolar teeth.  

PubMed

A review of 400 horses referred because of dental disorders showed 44 cases to suffer from primary disorders of their incisors and 11 from canine or 1st premolar teeth disorders. The remaining 345 horses suffered from primary disorders of the cheek teeth. Disorders of incisors included traumatic damage to teeth and their supporting bones, retained deciduous, displaced and supernumerary incisors; brachygnathia and abnormalities of wear, with most of the latter disorders being secondary to primary disorders of the cheek teeth Only 3 cases of apical infection of incisors were recognised. Most cases of fractured incisors responded well to conservative therapy. Retained deciduous incisors were extracted, but most cases with supernumerary and displaced incisors, or brachygnathia were treated conservatively. Most disorders of the canine and 1st premolar were developmental displacements that caused bitting problems (abnormalities of head movement associated with the bit), and these cases responded well to extraction of the displaced teeth. PMID:10505951

Dixon, P M; Tremaine, W H; Pickles, K; Kuhns, L; Hawe, C; McCann, J; McGorum, B; Railton, D I; Brammer, S

1999-09-01

139

Bacterial penetration of the root canal of intact incisor teeth after a simulated traumatic injury.  

PubMed

One of the aims in treating traumatised teeth is to maintain the vitality of the pulp or allow conditions favourable for pulp revascularisation. However, infection of the pulp and root canal system may prevent this. A number of pathways have been proposed that allow bacteria to invade the root canal system, however most of these pathways cannot account for pulp infection in teeth that did not sustain injury to the periodontal attachment. Enamel/dentine cracks have been proposed as a portal for bacterial invasion of seemingly intact teeth and the aim of this study was to determine if bacteria could invade the root canal system after a simulated traumatic episode. Twenty intact and sound upper central incisors were chosen and prepared. One tooth was selected as a sterility control and the external crown surface of the remaining 19 teeth was subjected to infection with Streptococcus gordonii in a bacterial microleakage model. Over 7 days samples of growth media from the root canal system were taken and tested for bacteria. Sixteen of the teeth did not demonstrate bacterial invasion over the time frame. These teeth were then prepared for testing in a pendulum impact device and were subjected to a blow which did not fracture the crowns or dislodge the tooth from its simulated alveolus. The teeth were then prepared and tested in the bacterial microleakage model. After impact seven of the teeth demonstrated bacterial invasion of the root canal system (P = 0.002). These teeth were then reprepared for testing in the bacterial microleakage model. The crowns of five teeth, selected at random, were coated with two layers of light cured unfilled resin, the remaining two were used as positive controls. All the teeth coated with resin did not demonstrate bacterial invasion (P = 0.00), while the positive controls demonstrated invasion. The results suggested that enamel/dentine infractions were pathways for bacterial invasion of the root canal system of traumatised teeth. The application of unfilled resin to the anatomical crown prevented infection. PMID:9206377

Love, R M

1996-12-01

140

A development-based compartmentalization of the Drosophila central brain  

PubMed Central

The neuropile of the Drosophila brain is subdivided into anatomically discrete compartments. Compartments are rich in terminal neurite branching and synapses; they are the neuropile domains in which signal processing takes place. Compartment boundaries are defined by more or less dense layers of glial cells, as well as long neurite fascicles. These fascicles are formed during the larval period when the approximately 100 neuronal lineages that constitute the Drosophila central brain differentiate. Each lineage forms an axon tract with a characteristic trajectory in the neuropile; groups of spatially related tracts congregate into the brain fascicles that can be followed from the larva throughout metamorphosis into the adult stage. In this paper we provide a map of the adult brain compartments and the relevant fascicles defining compartmental boundaries. We have identified the neuronal lineages contributing to each fascicle, which allowed us to directly compare compartments of the larval and adult brain. Most adult compartments can be recognized already in the early larval brain where they form a “protomap” of the later adult compartments. Our analysis highlights the morphogenetic changes shaping the Drosophila brain; the data will be important for studies that link early acting genetic mechanisms to the adult neuronal structures and circuits controlled by these mechanisms. PMID:20533357

Pereanu, Wayne; Kumar, Abilasha; Jennett, Arnim; Reichert, Heinrich; Hartenstein, Volker

2010-01-01

141

Ground-based Fourier transform infrared spectroscopy in central Mexico  

NASA Astrophysics Data System (ADS)

Altzomoni is a high altitude station in central Mexico (19.12 N, 98.65 W, 4000 m a.s.l.) for continuous measurements of various atmospheric parameters. It is located within the Izta-Popo National Park and is operated remotely from the UNAM campus. Since May 2012, high resolution solar absorption spectra have been recorded from this site using a FTIR from Bruker (HR120/5) equipped with MCT, InSb and InGaAs detectors and various optical filters. In this contribution we present a detailed description of the measurement site and the instrumental set-up including a record of the instrumental line-shapes (modulation efficiency and phase error) obtained from cell measurements and analyzed with the LINEFIT code. A preliminary analysis of almost two years of spectra recorded at the Altzomoni site resulting in profile retrievals of four NDACC gases O3, CO, HF and HCl is presented. The retrieval code PROFFIT is used and the Averaging Kernels and an error analysis are used to describe the quality of the measurements. The annual cycles in the time series of O3 and CO are presented and discussed, as well as some examples of anomalies due to volcanic gas emissions of HF and HCl are shown. The presented work is part of an effort to certify this station as part of the NDACC international network.

Plaza, Eddy; Stremme, Wolfgang; Bezanilla, Alejandro; Baylon, Jorge; Grutter, Michel; Blumenstock, Thomas; Hase, Frank

2014-05-01

142

Chytridiomycosis risk among Central European amphibians based on surveillance data.  

PubMed

The Czech Republic hosts a surprisingly rich biodiversity of amphibians representing the majority of amphibian species present in all of Central and Eastern Europe. Surveillance data of Batrachochytrium dendrobatidis (Bd) collected during 2008 to 2012 were analysed for basic patterns of prevalence and infection intensity among species, age groups and localities. In addition, an investigation was made into possible data bias due to varying PCR inhibition. Infection prevalence in the genus Pelophylax was significantly higher than in other sampled taxa, while Bombina and Bufo were infected with intermediate prevalence. Individual mortalities putatively caused by chytridiomycosis were detected in Bombina and Bufo, but not in Pelophylax. Differences among localities were seen to modulate the pathogen's infection rate and influence overall individual infection intensities. PCR inhibition occurred significantly more often in samples from the genus Pelophylax than in other tested taxa (Bufo bufo, B. viridis, Bombina bombina, Pelobates fuscus and Rana dalmatina). Although we found no completely inhibited samples within the genus Bombina, the infection loads were lower in the sample set processed without bovine serum albumin, suggesting some level of PCR inhibition. The combination of high Bd prevalence with no apparent deleterious effect and the high dispersal abilities of water frogs predispose them to act as vectors for chytridiomycosis. It is possible that the role of Pelophylax frogs in the spread of Bd is overlooked due to a large proportion of unrecognized false negatives, but this issue needs further confirmation. PMID:25392037

Balá, Vojtech; Vojar, Jir?í; Civi, Petr; Andera, Martin; Rozínek, Roman

2014-11-14

143

A diagnostic dilemma of central skull base osteomyelitis mimicking neoplasia in a diabetic patient  

PubMed Central

We present a case which illustrates the diagnostic difficulty in distinguishing between osteomyelitis of the central skull base and base of skull tumours. A woman in her early forties presented with seizures and multiple cranial nerve palsies. She also had a background of chronic otalgia and poorly controlled diabetes mellitus. The clinical diagnosis of skull base osteomyelitis (SBO) was made, but both MRI and bone scans were unable to distinguish this from a skull base malignancy on imaging criteria. Eventually biopsies were required to exclude the diagnosis of malignancy and the patient was treated for central SBO. PMID:23355560

Ganhewa, Aparna Dasunmalee; Kuthubutheen, Jafri

2013-01-01

144

Biofilm-based central line-associated bloodstream infections.  

PubMed

Different types of central venous catheters (CVCs) have been used in clinical practice to improve the quality of life of chronically and critically ill patients. Unfortunately, indwelling devices are usually associated with microbial biofilms and eventually lead to catheter-related bloodstream infections (CLABSIs).An estimated 250,000-400,000 CLABSIs occur every year in the United States, at a rate of 1.5 per 1,000 CVC days and a mortality rate of 12-25 %. The annual cost of caring for patients with CLABSIs ranges from 296 million to 2.3 billion dollars.Biofilm formation occurs on biotic and abiotic surfaces in the clinical setting. Extensive studies have been conducted to understand biofilm formation, including different biofilm developmental stages, biofilm matrix compositions, quorum-sensing regulated biofilm formation, biofilm dispersal (and its clinical implications), and multi-species biofilms that are relevant to polymicrobial infections.When microbes form a matured biofilm within human hosts through medical devices such as CVCs, the infection becomes resistant to antibiotic treatment and can develop into a chronic condition. For that reason, many techniques have been used to prevent the formation of biofilm by targeting different stages of biofilm maturation. Other methods have been used to diagnose and treat established cases of CLABSI.Catheter removal is the conventional management of catheter associated bacteremia; however, the procedure itself carries a relatively high risk of mechanical complications. Salvaging the catheter can help to minimize these complications.In this article, we provide an overview of microbial biofilm formation; describe the involvement of various genetic determinants, adhesion proteins, organelles, mechanism(s) of biofilm formation, polymicrobial infections, and biofilm-associated infections on indwelling intravascular catheters; and describe the diagnosis, management, and prevention of catheter-related bloodstream infections. PMID:25366227

Yousif, Ammar; Jamal, Mohamed A; Raad, Issam

2015-01-01

145

Evaluation of the Effect of Different Ferrule Designs on Fracture Resistance of Maxillary Incisors Restored with Bonded Posts and Cores  

PubMed Central

Introduction: In cases of severe hard tissue loss, 2 mm circumferential ferrule is difficult to achieve. So in these cases we should use different ferrule designs. This in vitro study investigated the effect of different ferrule designs on the fracture resistance of teeth restored with bonded post and cores. Materials and Methods: Forty freshly-extracted central incisors were endodontically treated. The teeth were randomly divided into four groups; group 1 were teeth with 2 mm circumferential ferrule above the CEJ, group 2 were teeth with 2 mm ferrule only on the palatal side of the teeth, group 3 consisted of teeth with 2 mm ferrule only on the facial side and group 4 were teeth with 2 mm ferrule on the palatal and facial side of teeth with interproximal concavities. All teeth were restored with fiber posts and composite cores. The specimen was mounted on a universal testing machine and compressive load was applied to the long axis of the specimen until failure occurred. Results: The fracture resistance was 533.79 ± 232.28 in group 1, 634.75± 133.35 in group 2, 828.90 ±118.27 in group 3 and 678.78± 160.20 in group 4. The post hoc analysis showed statistically significant difference between groups 1 and 3. Conclusions: The results of this in vitro study showed that facial ferrule increases the fracture resistance of endodontically treated teeth restored with bonded post and cores. PMID:21998789

Mahdavi Izadi, Z.; Jalalian, E.; Eyvaz Ziaee, A.; Zamani, L.; Javanshir, B.

2010-01-01

146

Essentiality of Early Diagnosis of Molar Incisor Hypomineralization in Children and Review of its Clinical Presentation, Etiology and Management  

PubMed Central

Abstract Molar incisor hypomineralization (MIH) is a common developmental condition resulting in enamel defects in first permanent molars and permanent incisors. It presents at eruption of these teeth. One to four molars, and often also the incisors, could be affected. Since first recognized, the condition has been puzzling and interpreted as a distinct phenomenon unlike other enamel disturbances. Early diagnosis is essential since, rapid breakdown of tooth structure may occur, giving rise to acute symptoms and complicated treatment. The purpose of this article is to review MIH and illustrate its diagnosis and clinical management in young children. How to cite this article: Garg N, Jain AK, Saha S, Singh J. Essentiality of Early Diagnosis of Molar Incisor Hypomineralization in Children and Review of its Clinical Presentation, Etiology and Management. Int J Clin Pediatr Dent 2012;5(3):190-196. PMID:25206166

Jain, Abhay Kumar; Saha, Sonali; Singh, Jaspal

2012-01-01

147

Prevalence of tooth agenesis and peg-shaped maxillary lateral incisor associated with palatally displaced canine (PDC) anomaly  

Microsoft Academic Search

Fifty-eight nonsyndromic North American white orthodontic patients with palatal displacement of one or both maxillary canine teeth were studied for associated tooth agenesis and peg-shaped maxillary lateral incisors. Agenesis of permanent teeth was identified by x-ray film analysis. Conical crown-size reduction (peg-shape anomaly) of the maxillary lateral incisor (I2) was determined by direct observation. Increases in absence of third molars

Sheldon Peck; Leena Peck; Matti Kataja

1996-01-01

148

Endodontic Treatment of a Maxillary Lateral Incisor with Two Roots; A Case Report with 6 Months Follow-Up  

PubMed Central

Maxillary lateral incisors are widely known to be single rooted with one root canal. Although rare cases with root canal variations are being reported in many populations, the reports regarding Iranian population is extremely limited. In this report, we are presenting the endodontic treatment of a double rooted maxillary lateral incisor. These rare root-canal variations should be considered in pretreatment evaluations by clinicians who perform endodontic treatments. PMID:25469361

Hoseini, Atefeh; Abbaszadegan, Abbas

2014-01-01

149

Reattachment of fractured maxillary incisors using fiber-reinforced post: Two case reports  

PubMed Central

Objective: The reattachment of the crown fragment to a fractured tooth is a conservative treatment that should be considered for young patients with crown-root fractures to the maxillary incisors if the subgingival fracture can be exposed to provide isolation. Gingivectomy, the surgical or orthodontic extrusion of the apical fragment is necessary to expose the subgingival fracture. This report demonstrates the treatment of two cases with the combination of gingivectomy or resective osseous surgery, reattachment of coronal fracture and fiber-reinforced polymer posts and shows three years long term follow-up. Subgingivally extended crown-root fractures of maxillary incisors were restored with a combination of chemically cured resin material, light cured resin material and polyethylene fiber. Conclusion: Within the limitations of this case report, it was demonstrated that reattachment of tooth fragments can successfully benefit periodontal health, aesthetic needs and normal functioning after three years. PMID:22509128

Tosun, Gul; Yildiz, Esma; Elbay, Mesut; Sener, Yagmur

2012-01-01

150

Management of geminated maxillary lateral incisor using cone beam computed tomography as a diagnostic tool  

PubMed Central

Geminated teeth are consequences of developmental anomalies leading to joined elements, due to incomplete attempt of one tooth germ to divide into two. This case report describes successful endodontic treatment of an unaesthetic geminated permanent maxillary lateral incisor tooth and its esthetic rehabilitation using all ceramic crowns. Newer imaging technique like cone beam computed tomography was taken for the better understanding of the complicated root canal morphology. PMID:24944458

James, Elizabeth Prabha; Johns, Dexton Antony; Johnson, KI; Maroli, Ramesh Kumar

2014-01-01

151

Root resorption of the maxillary lateral incisor caused by impacted canine: a literature review  

Microsoft Academic Search

Root resorption of maxillary lateral incisors caused by erupting canines is well known and a relatively common phenomenon.\\u000a However, much debate and conflicting evidence exists with regard to the actual resorption trigger and potential etiological\\u000a factors involved. Consequently, there are no obvious clinical clues concerning prevention and diagnosis as well as subsequent\\u000a treatment decisions. The introduction of cone beam computer

A. Alqerban; R. Jacobs; P. Lambrechts; G. Loozen; G. Willems

2009-01-01

152

Appearance of the first cemental annulation of permanent incisor teeth of the domestic cat (Felis catus)  

E-print Network

studied histologically to analyze the early growth pattern of dental cementum of permanent teeth. Thin sections (H-E stained) of incisor teeth were prepared and examined microscopically. The observations of individual teeth were recorded.... The references herein are consistent with the style and format of Laboratory Animal Science. REVIEW OF LITERATURE Annulation counts in dental cementum have been used to determine age in mammals. The formation of dentinal and cemental layers have been shown...

Choi, In-Back

1983-01-01

153

All the Mandibular Incisors with Double Canals in a Single Patient: A Rare Case  

PubMed Central

Single rooted tooth are considered to be the easiest for root canal treatment. The literature has documented cases with single rooted tooth showing more than single canal. Understanding of root canal morphology thus is an important aspect to be considered for successful endodontic treatment. The case presented here shows a rare entity of having double canals in all the mandibular incisors in a single patient. PMID:25859107

Daokar, Sadashiv G; Kalekar (Yadao), Anita S; Ghunawat, Dhananjay B; Kakde, Deepak D

2015-01-01

154

Expression of MicroRNAs in the Stem Cell Niche of the Adult Mouse Incisor  

PubMed Central

The mouse incisor is a valuable but under-utilized model organ for studying the behavior of adult stem cells. This remarkable tooth grows continuously throughout the animal's lifetime and houses two distinct epithelial stem cell niches called the labial and lingual cervical loop (laCL and liCL, respectively). These stem cells produce progeny that undergo a series of well-defined differentiation events en route to becoming enamel-producing ameloblasts. During this differentiation process, the progeny move out of the stem cell niche and migrate toward the distal tip of the tooth. Although the molecular pathways involved in tooth development are well documented, little is known about the roles of miRNAs in this process. We used microarray technology to compare the expression of miRNAs in three regions of the adult mouse incisor: the laCL, liCL, and ameloblasts. We identified 26 and 35 differentially expressed miRNAs from laCL/liCL and laCL/ameloblast comparisons, respectively. Out of 10 miRNAs selected for validation by qPCR, all transcripts were confirmed to be differentially expressed. In situ hybridization and target prediction analyses further supported the reliability of our microarray results. These studies point to miRNAs that likely play a role in the renewal and differentiation of adult stem cells during stem cell-fueled incisor growth. PMID:21931743

Jheon, Andrew H.; Li, Chun-Ying; Wen, Timothy; Michon, Frederic; Klein, Ophir D.

2011-01-01

155

On the cutting edge of organ renewal: identification, regulation and evolution of incisor stem cells  

PubMed Central

The rodent incisor is one of a number of organs that grow continuously throughout the life of an animal. Continuous growth of the incisor arose as an evolutionary adaptation to compensate for abrasion at the distal end of the tooth. The sustained turnover of cells that deposit the mineralized dental tissues is made possible by epithelial and mesenchymal stem cells residing at the proximal end of the incisor. A complex network of signaling pathways and transcription factors regulates the formation, maintenance, and differentiation of these stem cells during development and throughout adulthood. Research over the past 15 years has led to significant progress in our understanding of this network, which includes FGF, BMP, Notch, and Hh signaling, as well as cell adhesion molecules and microRNAs. This review surveys key historical experiments that laid the foundation of the field and discusses more recent findings that definitively identified the stem cell population, elucidated the regulatory network, and demonstrated possible genetic mechanisms for the evolution of continuously growing teeth. PMID:24307456

Hu, Jimmy Kuang-Hsien; Mushegyan, Vagan; Klein, Ophir D.

2014-01-01

156

An FGF signaling loop sustains the generation of differentiated progeny from stem cells in mouse incisors.  

PubMed

Rodent incisors grow throughout adult life, but are prevented from becoming excessively long by constant abrasion, which is facilitated by the absence of enamel on one side of the incisor. Here we report that loss-of-function of sprouty genes, which encode antagonists of receptor tyrosine kinase signaling, leads to bilateral enamel deposition, thus impeding incisor abrasion and resulting in unchecked tooth elongation. We demonstrate that sprouty genes function to ensure that enamel-producing ameloblasts are generated on only one side of the tooth by inhibiting the formation of ectopic ameloblasts from self-renewing stem cells, and that they do so by preventing the establishment of an epithelial-mesenchymal FGF signaling loop. Interestingly, although inactivation of Spry4 alone initiates ectopic ameloblast formation in the embryo, the dosage of another sprouty gene must also be reduced to sustain it after birth. These data reveal that the generation of differentiated progeny from a particular stem cell population can be differently regulated in the embryo and adult. PMID:18077585

Klein, Ophir D; Lyons, David B; Balooch, Guive; Marshall, Grayson W; Basson, M Albert; Peterka, Miroslav; Boran, Tomas; Peterkova, Renata; Martin, Gail R

2008-01-01

157

An FGF signaling loop sustains the generation of differentiated progeny from stem cells in mouse incisors  

PubMed Central

Rodent incisors grow throughout adult life, but are prevented from becoming excessively long by constant abrasion, which is facilitated by the absence of enamel on one side of the incisor. Here we report that loss-of-function of Sprouty genes, which encode antagonists of receptor tyrosine kinase signaling, leads to bilateral enamel deposition, thus impeding incisor abrasion and resulting in unchecked tooth elongation. We demonstrate that Sprouty genes function to ensure that enamel-producing ameloblasts are generated on only one side of the tooth by inhibiting the formation of ectopic ameloblasts from self-renewing stem cells, and that they do so by preventing the establishment of an epithelial-mesenchymal FGF signaling loop. Interestingly, whilst inactivation of Spry4 alone initiates ectopic ameloblast formation in the embryo, the dosage of another Sprouty gene must also be reduced to sustain it after birth. These data reveal that the generation of differentiated progeny from a particular stem cell population can be differently regulated in the embryo and adult. PMID:18077585

Klein, Ophir D.; Lyons, David B.; Balooch, Guive; Marshall, Grayson W.; Basson, M. Albert; Peterka, Miroslav; Boran, Tomas; Peterkova, Renata; Martin, Gail R.

2008-01-01

158

Interproximal wear versus incisors extraction to solve anterior lower crowding: A systematic review  

PubMed Central

OBJECTIVE: To determine by means of a systematic review the best treatment, whether interproximal wear or incisor extraction, to correct anterior lower crowding in Class I patients in permanent dentition. METHODS: A literature review was conducted using MEDLINE, Scopus and Web of Science to retrieve studies published between January 1950 and October 2013. In selecting the sample, the following inclusion criteria were applied: studies involving interproximal wear and/or extraction of mandibular incisors, as well as Class I cases with anterior lower crowding in permanent dentition. RESULTS: Out of a total of 943 articles found after excluding duplicates, 925 were excluded after abstract analysis. After full articles were read, 13 were excluded by the eligibility criteria and one due to methodological quality; therefore, only fours articles remained: two retrospective and two randomized prospective studies. Data were collected, analyzed and organized in tables. CONCLUSION: Both interproximal wear and mandibular incisor extraction are effective in treating Class I malocclusion in permanent dentition with moderate anterior lower crowding and pleasant facial profile. There is scant evidence to determine the best treatment option for each case. Clinical decision should be made on an individual basis by taking into account dental characteristics, crowding, dental and oral health, patient's expectations and the use of set-up models. PMID:25741827

de Almeida, Natália Valli; Silveira, Giordani Santos; Pereira, Daniele Masterson Tavares; Mattos, Claudia Trindade; Mucha, José Nelson

2015-01-01

159

A case of maloccluded incisor teeth in a beaver: castor canadensis.  

PubMed

A three-year-old female beaver (Castor canadensis) was referred to the Veterinary Teaching Hospital of Chungbuk National University. It had been raised in the Cheong-ju zoo and had a history of malocclusion caused by improper feeding. General anesthesia was induced, and preoperative intraoral dental radiographs of the rostal maxillary and mandibular dentition were taken and lateral and ventrodorsal extraoral radiographs of the cheek teeth were also taken. The radiographs were negative for apical pathology and revealed a normal appearance of the cheek teeth. The lesion was likely to be related to the excessive length of the maxillary and mandibular incisors. Odontoplasty was performed to reduce overgrowth of the crowns of the incisors. Sequential transverse sections were removed until the crown was reduced by approximately its original length. The pulp chamber was not approached during the operation, as confirmed by postoperative intraoral radiographic evaluation of the incisors. Recovery from anesthesia was uneventful and the beaver returned to normal masticatory activities immediately after the operation. PMID:15933441

Kim, Joong-hyun; Lee, Jae Yeong; Han, Tae-Sung; Han, Kyu-bo; Kang, Seong Soo; Bae, Chun Sik; Choi, Seok Hwa

2005-06-01

160

Periodontal consequences of mandibular incisor proclination during presurgical orthodontic treatment in Class III malocclusion patients.  

PubMed

Abstract Objective: To test the hypothesis that periodontal changes are similar between proclined and minimal-changed mandibular incisor position groups during presurgical orthodontic treatment for Class III orthognathic surgery. Materials and Methods: The following measurements were performed before and after presurgical orthodontic treatment of 75 patients (proclination group, 39 subjects; minimal-change group, 36 subjects): clinical crown length, sulcus and bone probing depths, and width of attached gingiva from clinical examination; infradentale-to-MP (perpendicular distance of infradentale to mandibular plane) from examination of lateral cephalograms; and the distance between the cementoenamel junction and alveolar crest from examination of periapical radiographs. Data were compared between the two groups, and a regression analysis was performed to investigate factors affecting the periodontal changes. Results: In both groups, clinical crown length and bone probing depth increased during presurgical orthodontics (P < .05). Infradentale-to-MP and the width of attached gingiva decreased more in the proclination group than in the minimal-change group (P < .05). Proclination and protrusion of the mandibular incisors, and treatment duration affected the periodontal changes. Conclusions: The null hypothesis was rejected. Proclination of the mandibular incisors for decompensation in Class III surgery patients seems to result in labial alveolar bone recession and a decrease in width of attached gingiva. However, the amount of the periodontal recession appeared to be clinically insignificant. PMID:25090134

Choi, Yoon Jeong; Chung, Chooryung J; Kim, Kyung-Ho

2014-08-01

161

Effect of single-dose amoxicillin on rat incisor odontogenesis: a morphological study.  

PubMed

The effect of exposure to amoxicillin on tooth development remains to be elucidated. The purpose of this study was to investigate the effect of amoxicillin on rat incisor odontogenesis. Male Wistar rats weighing approximately 100 g were given a single intraperitoneal injection of 3.0 g/kg body weight amoxicillin. One week after injection, the rats were fixed, and the lower incisors were demineralized and prepared into paraffin sections for light microscopy (LM) and immunohistochemistry. Undemineralized samples were embedded in resin and ground for processing for contact microradiography (CMR) and scanning electron microscopy (SEM). Serum calcium, phosphate, and magnesium concentrations were measured. At 1 week after amoxicillin administration, LM, CMR, and SEM revealed a clear increase in the area of interglobular dentin, representing disruption of mineralization by odontoblasts. Immunohistochemistry demonstrated moderate levels of the small integrin-binding ligand N-linked glycoprotein family dentin matrix protein 1 in large areas of interglobular dentin. On the other hand, no morphological alteration or hypomineralization was observed in the enamel. Serum calcium values showed no significant differences between the control and experimental rats during the experimental period although both serum phosphate and magnesium levels increased at day 1 after amoxicillin injection. The results suggest that a single dose of amoxicillin specifically affects normal tooth dentin mineralization, but not enamel mineralization in rat incisor odontogenesis. The present results further our understanding of the clinical association between dentin abnormality and amoxicillin exposure during tooth development. PMID:21717095

Kumazawa, Kaido; Sawada, Takashi; Yanagisawa, Takaaki; Shintani, Seikou

2012-06-01

162

Hedgehog signaling regulates the generation of ameloblast progenitors in the continuously growing mouse incisor  

PubMed Central

In many organ systems such as the skin, gastrointestinal tract and hematopoietic system, homeostasis is dependent on the continuous generation of differentiated progeny from stem cells. The rodent incisor, unlike human teeth, grows throughout the life of the animal and provides a prime example of an organ that rapidly deteriorates if newly differentiated cells cease to form from adult stem cells. Hedgehog (Hh) signaling has been proposed to regulate self-renewal, survival, proliferation and/or differentiation of stem cells in several systems, but to date there is little evidence supporting a role for Hh signaling in adult stem cells. We used in vivo genetic lineage tracing to identify Hh-responsive stem cells in the mouse incisor and we show that sonic hedgehog (SHH), which is produced by the differentiating progeny of the stem cells, signals to several regions of the incisor. Using a hedgehog pathway inhibitor (HPI), we demonstrate that Hh signaling is not required for stem cell survival but is essential for the generation of ameloblasts, one of the major differentiated cell types in the tooth, from the stem cells. These results therefore reveal the existence of a positive-feedback loop in which differentiating progeny produce the signal that in turn allows them to be generated from stem cells. PMID:20978073

Seidel, Kerstin; Ahn, Christina P.; Lyons, David; Nee, Alexander; Ting, Kevin; Brownell, Isaac; Cao, Tim; Carano, Richard A. D.; Curran, Tom; Schober, Markus; Fuchs, Elaine; Joyner, Alexandra; Martin, Gail R.; de Sauvage, Frederic J.; Klein, Ophir D.

2010-01-01

163

The upper dentition and face of Pondaungia cotteri from central Myanmar  

Microsoft Academic Search

A specimen of Pondaungia from the late middle Eocene Pondaung Formation in central Myanmar includes maxillary fragments and parts of the dentition, some hitherto undocumented, including the upper central incisor, canine, premolars and molars. Pondaungia has a large spatulate I1 closely resembling that of crown anthropoids. It possesses a stout projecting upper canine (like anthropoids) but differs from that tooth

Nobuo Shigehara; Masanaru Takai; Richard F. Kay; Aye Ko Aung; Aung Naing Soe; Soe Thura Tun; Takehisa Tsubamato; Tin Thein

2002-01-01

164

The Design of Improved Fuzzy Controller Based on MCU for Central Air Conditioner  

Microsoft Academic Search

A system structure and the procedure of fuzzy control of central air conditioner (CAC) in building are presented in this paper. Discuss the design of improved fuzzy controller about room temperature controller in detail, including the hardware design and software programming based on MCU (Micro programmed Control Unit). The functions of temperature controller are completed under the application that includes

Yingjun Guo; Yingbao Zhao; Zengli Lu; Jianguang Liu

2008-01-01

165

A multidisciplinary treatment of congenitally missing maxillary lateral incisors: a 14-year follow-up case report.  

PubMed

Absence of the maxillary lateral incisor creates an aesthetic problem which can be managed in various ways. The condition requires careful treatment planning and consideration of the options and outcomes following either space closure or prosthetic replacement. Recent developments in restorative dentistry have warranted a re-evaluation of the approach to this clinical situation. Factors relating both to the patient and the teeth, including the presentation of malocclusion and the effect on the occlusion must be considered. The objective of this study was to describe the etiology, prevalence and alternative treatment modalities for dental agenesis and to present a clinical case of agenesis of the maxillary lateral incisors treated by the closure of excessive spaces and canine re-anatomization. A clinical case is presented to illustrate the interdisciplinary approach between orthodontics and restorative dentistry for improved esthetic results. In this report, the treatment of a girl with a Class II malocclusion of molars and canines with missing maxillary lateral incisors and convex facial profile is shown. Treatment was successfully achieved and included the space closure of the areas corresponding to the missing upper lateral incisors, through movement of the canines and the posterior teeth to mesial by fixed appliances as well as the canines transformation in the maxillary lateral incisors. This is a 14-year follow-up case report involving orthodontics and restorative dentistry in which pretreatment, posttreatment, and long-term follow-up records for the patient are presented. PMID:25466480

de Almeida, Renato Rodrigues; Morandini, Ana Carolina Faria; Almeida-Pedrin, Renata Rodrigues de; de Almeida, Marcio Rodrigues; Castro, Renata Cristina Faria Ribeiro; Insabralde, Natalia Martins

2014-01-01

166

Ectopia and Partial Transposition of Mandibular Lateral Incisors in a Child Patient  

PubMed Central

Dental ectopia is a rare clinical finding characterized by a change in the normal tooth eruption pathway. In more severe cases, nontreated ectopia may develop into either partial or total transposition. The early diagnosis is of crucial importance for establishing a treatment planning correctly. Therefore, the present paper is aimed at reporting an unusual case of a 11-year-old boy with ectopic eruption and partial transposition of mandibular permanent lateral incisors as well as the diagnosis and therapeutic outcomes involving such an anomaly. PMID:21991466

de Paula, Viviane Andrade Cancio; Giacomet, Felipe; Bolognese, Ana Maria; Maia, Lucianne Cople

2011-01-01

167

Anti-triangle centrality-based community detection in complex networks.  

PubMed

Community detection has been extensively studied in the past decades largely because of the fact that community exists in various networks such as technological, social and biological networks. Most of the available algorithms, however, only focus on the properties of the vertices, ignoring the roles of the edges. To explore the roles of the edges in the networks for community discovery, the authors introduce the novel edge centrality based on its antitriangle property. To investigate how the edge centrality characterises the community structure, they develop an approach based on the edge antitriangle centrality with the isolated vertex handling strategy (EACH) for community detection. EACH first calculates the edge antitriangle centrality scores for all the edges of a given network and removes the edge with the highest score per iteration until the scores of the remaining edges are all zero. Furthermore, EACH is characterised by being free of the parameters and independent of any additional measures to determine the community structure. To demonstrate the effectiveness of EACH, they compare it with the state-of-the art algorithms on both the synthetic networks and the real world networks. The experimental results show that EACH is more accurate and has lower complexity in terms of community discovery and especially it can gain quite inherent and consistent communities with a maximal diameter of four jumps. PMID:25014378

Jia, Songwei; Gao, Lin; Gao, Yong; Wang, Haiyang

2014-06-01

168

Trade and Industrial Upgrading in Countries of Central and Eastern Europe: Patterns of Scale and Scope-based Learning  

Microsoft Academic Search

The paper explores mechanisms that link trade and restructuring in countries of central and eastern Europe through a learning and industrial upgrading perspective. A theoretical model based on notions of scale (relative concentration in trade) and scope (changes in product variety) is introduced and applied, based on detailed product level data for six central and east European countries (CEECs). During

Ulrike Hotopp; Slavo Radosevic; Kate Bishop

2002-01-01

169

TRADE AND INDUSTRIAL UPGRADING IN COUNTRIES OF CENTRAL AND EASTERN EUROPE: PATTERNS OF SCALE AND SCOPE-BASED LEARNING1  

Microsoft Academic Search

The paper explores mechanisms that link trade and restructuring in countries of central and eastern Europe through a learning and industrial upgrading perspective. A theoretical model based on notions of scale (relative concentration in trade) and scope (changes in product variety) is introduced and applied, based on detailed product level data for six central and east European countries (CEECs). During

Ulrike Hotopp; Slavo Radosevic; Kate Bishop

170

Ring1a/b polycomb proteins regulate the mesenchymal stem cell niche in continuously growing incisors.  

PubMed

Rodent incisors are capable of growing continuously and the renewal of dental epithelium giving rise to enamel-forming ameloblasts and dental mesenchyme giving rise to dentin-forming odontoblasts and pulp cells is achieved by stem cells residing at their proximal ends. Although the dental epithelial stem cell niche (cervical loop) is well characterized, little is known about the dental mesenchymal stem cell niche. Ring1a/b are the core Polycomb repressive complex1 (PRC1) components that have recently also been found in a protein complex with BcoR (Bcl-6 interacting corepressor) and Fbxl10. During mouse incisor development, we found that genes encoding members of the PRC1 complex are strongly expressed in the incisor apical mesenchyme in an area that contains the cells with the highest proliferation rate in the tooth pulp, consistent with a location for transit amplifying cells. Analysis of Ring1a(-/-);Ring1b(cko/cko) mice showed that loss of Ring1a/b postnatally results in defective cervical loops and disturbances of enamel and dentin formation in continuously growing incisors. To further characterize the defect found in Ring1a(-/-);Ring1b(cko/cko) mice, we demonstrated that cell proliferation is dramatically reduced in the apical mesenchyme and cervical loop epithelium of Ring1a(-/-);Ring1b(cko/cko) incisors in comparison to Ring1a(-/-);Ring1b(fl/fl)cre- incisors. Fgf signaling and downstream targets that have been previously shown to be important in the maintenance of the dental epithelial stem cell compartment in the cervical loop are downregulated in Ring1a(-/-);Ring1b(cko/cko) incisors. In addition, expression of other genes of the PRC1 complex is also altered. We also identified an essential postnatal requirement for Ring1 proteins in molar root formation. These results show that the PRC1 complex regulates the transit amplifying cell compartment of the dental mesenchymal stem cell niche and cell differentiation in developing mouse incisors and is required for molar root formation. PMID:22562112

Lapthanasupkul, Puangwan; Feng, Jifan; Mantesso, Andrea; Takada-Horisawa, Yuki; Vidal, Miguel; Koseki, Haruhiko; Wang, Longlong; An, Zhengwen; Miletich, Isabelle; Sharpe, Paul T

2012-07-15

171

Theoretical Study of the Effect of Enamel Parameters on Laser-Induced Surface Acoustic Waves in Human Incisor  

NASA Astrophysics Data System (ADS)

The laser ultrasound technique has great potential for clinical diagnosis of teeth because of its many advantages. To study laser surface acoustic wave (LSAW) propagation in human teeth, two theoretical methods, the finite element method (FEM) and Laguerre polynomial extension method (LPEM), are presented. The full field temperature values and SAW displacements in an incisor can be obtained by the FEM. The SAW phase velocity in a healthy incisor and dental caries is obtained by the LPEM. The methods and results of this work can provide a theoretical basis for nondestructive evaluation of human teeth with LSAWs.

Yuan, Ling; Sun, Kaihua; Shen, Zhonghua; Ni, Xiaowu; Lu, Jian

2014-07-01

172

Investigation of the maxillary lateral incisor agenesis and associated dental anomalies in an orthodontic patient population  

PubMed Central

Objectives: The aim of this study was to investigate the prevalence of maxillary lateral incisor (MLI) agenesis and associated dental anomalies as well as skeletal patterns in an orthodontic population, and then to compare it with the prevalence of these anomalies in the general population. Study Design: The material of the present study included the records of the 3872 orthodontic patients. The followings were recorded for each subject with the agenesis of MLI: Age, sex, unilateral or bilateral absence, anterior-posterior skeletal relationship of the maxilla and mandible, and presence of associated dental anomalies. The occurrence of these anomalies was compared with data previously reported for the general populations. Results: Of the 3872 patients examined, 94 were found to have agenesis of the MLI, representing a prevalence of 2.4 per cent, with females being more frequently observed. The most commonly found associated anomalies were ectopic eruption of maxillary canines and reduced or peg- shaped contralateral incisor with the frequencies of 21.3 per cent and 20.2 per cent respectively. Conclusions: Patients with agenesis of MLI showed a significantly higher prevalence of skeletal Class III malocclusion compared with the general population. The prevalence of ectopic eruption, transposition, and transmigration of the maxillary canine and reduced or peg- shaped MLIs were significantly increased. Key words:Hypodontia, missing laterals, associated dental anomalies. PMID:22549676

Kamak, Hasan; Yildirim, Hanifi; Ceylan, Ismail

2012-01-01

173

Shear bond strength of dentin and deproteinized enamel of AI mouse incisors  

PubMed Central

Purpose To investigate the adhesion through shear bond strength (SBS) testing of a resin composite bonded with a self-etching bonding system (SEB) to amelogenesis imperfecta (AI)-affected deproteinized mouse enamel or dentin; and to compare wild-type (WT), amelogenin null (AmelxKO) and matrix metalloproteinase-20 null (Mmp20KO) enamel and dentin phenotypes using microCT and nanoindentation. Methods Enamel incisor surfaces of WT, AmelxKO and Mmp20KO mice were treated with SEB with and without NaOCl and tested for SBS. Incisor dentin was also treated with SEB and tested for SBS. These surfaces were further examined by SEM. MicroCT and nanoindentation analyses were performed on mouse dentin and enamel. Data were analyzed for significance by ANOVA. Results Deproteinization did not improve SBS of SEB to these AI-affected enamel surfaces. SBS of AmelxKO teeth was similar in dentin and enamel; however, it was higher in Mmp20KO dentin. The nanohardness of knockout enamel was significantly lower than WT, while knockout dentin nanohardness was not different from WT. Conclusions Using animal AI models, it was demonstrated that enamel NaOCl deproteinization of hypoplastic and hypoplastic-hypomaturation enamel did not increase shear bond strength while removal of the defective enamel allowed optimal dentin bonding. PMID:25303500

Pugach, M.K.; Ozer, F.; Mulmadgi, R.; Li, Y.; Suggs, C.; Wright, J.T.; Bartlett, J.D.; Gibson, C.W.; Lindemeyer, R.G.

2014-01-01

174

Prevalence of lesions in incisors of mule deer from Colorado Springs, Colorado  

SciTech Connect

Lesions in teeth may be influenced by exposure to fluorides, malnutrition and trauma. Incisors of 228 mule deer (Odocoileus hemionus) taken from the USAF Academy, Colorado Springs, CO during the 1993 hunting season were examined for lesions. A classification scheme (scale = 0--5) for lesions was derived from the method of Shupe et al. 1963. Lesions were present in at least one incisor of 84.6% of deer. Of the deer with lesions, 86% had at least one tooth with very slight effect (one to few white spots), 9.8% had a slight effect (generalized mottling), 2.6% had a moderate effect (generalized mottling and wear), 10.04% had a marked effect (mottling and hypoplasia of the enamel) , and 0.5 % ad severe effects (hypoplasia of the enamel and abnormal wear). Lesions that affect the enamel are produced during the period of formation of the tooth. The severity of lesions depends on the cause and the length of exposure to the causative agent. Generally mottling and hypoplasia of the enamel are associated with fluorosis. The relationship of lesions to bone and tooth fluoride concentrations was examined.

Borrero, L.M.; Scanlon, P.F. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Fisheries and Wildlife Science

1995-12-31

175

Development of a Physiologically-Based Pharmacokinetic Model of the Rat Central Nervous System  

PubMed Central

Central nervous system (CNS) drug disposition is dictated by a drug’s physicochemical properties and its ability to permeate physiological barriers. The blood–brain barrier (BBB), blood-cerebrospinal fluid barrier and centrally located drug transporter proteins influence drug disposition within the central nervous system. Attainment of adequate brain-to-plasma and cerebrospinal fluid-to-plasma partitioning is important in determining the efficacy of centrally acting therapeutics. We have developed a physiologically-based pharmacokinetic model of the rat CNS which incorporates brain interstitial fluid (ISF), choroidal epithelial and total cerebrospinal fluid (CSF) compartments and accurately predicts CNS pharmacokinetics. The model yielded reasonable predictions of unbound brain-to-plasma partition ratio (Kpuu,brain) and CSF:plasma ratio (CSF:Plasmau) using a series of in vitro permeability and unbound fraction parameters. When using in vitro permeability data obtained from L-mdr1a cells to estimate rat in vivo permeability, the model successfully predicted, to within 4-fold, Kpuu,brain and CSF:Plasmau for 81.5% of compounds simulated. The model presented allows for simultaneous simulation and analysis of both brain biophase and CSF to accurately predict CNS pharmacokinetics from preclinical drug parameters routinely available during discovery and development pathways. PMID:24647103

Badhan, Raj K. Singh; Chenel, Marylore; Penny, Jeffrey I.

2014-01-01

176

Anomalous maxillary lateral incisor--the only product of dental lamina, difficult classifiable in the time. Symptom of hypodontia syndrome non-described until present time.  

PubMed

The authors described anomalous development of maxillary lateral incisor non-yet published in stomatologic literature. Diagnostics and clinical findings of the anomaly and the prognosis of the affected tooth they based on the description of six longitudinal observed patients. The principal symptom of the anomaly is the disturbance of time-plan of the tooth development. Terms of the tooth mineralization, the time of eruption and root completion cannot be included either in deciduous or in permanent dentition. The tooth is the only product of the dental lamina; it has no predecessor or successor. Frequent disturbances of the eruption pathway result often in anomalous position of the tooth. Taking into consideration the fact that the anomaly appeared always in connection with hypodontia syndrome, it is possible to consider it to be the symptom of hypodontia syndrome. This fact is more significant as it enables to establish the diagnosis of hypodontia syndrome already in early deciduous dentition. PMID:14577137

Rozkovcová, E; Marková, M; Vásková, J

2003-01-01

177

A Coumarin-Based Fluorescent Probe as a Central Nervous System Disease Biomarker  

PubMed Central

Homocysteine and methylmalonic acid are important biomarkers for diseases associated with an impaired central nervous system (CNS). A new chemoassay utilizing coumarin-based fluorescent probe 1 to detect the levels of homocysteine is successfully implemented using Parkinson's disease (PD) patients' blood serum. In addition, a rapid identification of homocysteine and methylmalonic acid levels in blood serum of PD patients was also performed using the liquid chromatography-mass spectrometry (LC-MS). The results obtained from both analyses were in agreement. The new chemoassay utilizing coumarin-based fluorescent probe 1 offers a cost- and time-effective method to identify the biomarkers in CNS patients. PMID:25390405

Yap, Ann-Chee; Mahamad, Ummi Affah; Lim, Shen-Yang; Kim, Hae-Jo; Choo, Yeun-Mun

2014-01-01

178

Integrated flight/propulsion control system design based on a centralized approach  

NASA Technical Reports Server (NTRS)

An integrated flight/propulsion control system design is presented for the piloted longitudinal landing task with a modern, statically unstable, fighter aircraft. A centralized compensator based on the Linear Quadratic Gaussian/Loop Transfer Recovery methodology is first obtained to satisfy the feedback loop performance and robustness specificiations. This high-order centralized compensator is then partitioned into airframe and engine sub-controllers based on modal controllability/observability for the compensator modes. The order of the sub-controllers is then reduced using internally-balanced realization techniques and the sub-controllers are simplified by neglecting the insignificant feedbacks. These sub-controllers have the advantage that they can be implemented as separate controllers on the airframe and the engine while still retaining the important performance and stability characteristics of the full-order centralized compensator. Command prefilters are then designed for the closed-loop system with the simplified sub-controllers to obtain the desired system response to airframe and engine command inputs, and the overall system performance evaluation results are presented.

Garg, Sanjay; Mattern, Duane L.; Bullard, Randy E.

1989-01-01

179

Sulcus-Based MR Analysis of Focal Cortical Dysplasia Located in the Central Region  

PubMed Central

Objective Focal cortical dysplasias (FCDs) are mainly located in the frontal region, with a particular tropism for the central sulcus. Up to 30% of lesions are undetected (magnetic resonance [MR]-negative FCD patients) or belatedly diagnosed by visual analysis of MR images. We propose an automated sulcus-based method to analyze abnormal sulcal patterns associated with central FCD, taking into account the normal interindividual sulcal variability. Methods We retrospectively studied 29 right-handed patients with FCD in the central region (including 12 MR negative histologically-confirmed cases) and 29 right-handed controls. The analysis of sulcal abnormalities from T1-weighted MR imaging (MRI) was performed using a graph-based representation of the cortical folds and an automated sulci recognition system, providing a new quantitative criterion to describe sulcal patterns, termed sulcus energy. Results Group analysis showed that the central sulcus in the hemisphere ipsilateral to the FCD exhibited an abnormal sulcal pattern compared with controls (p = 0.032). FCDs were associated with abnormal patterns of the central sulci compared with controls (p = 0.006), a result that remained significant when MR-negative and MR-positive patients were considered separately, while the effects of sex, age and MR-field were not significant. At the individual level, sulcus energy alone failed to detect the FCD lesion. We found, however, a significant association between maximum z-scores and the site of FCD (p = 0.0046) which remained significant in MR-negative (p = 0.024) but not in MR-positive patients (p = 0.058). The maximum z-score pointed to an FCD sulcus in four MR-negative and five MR-positive patients. Conclusions We identified abnormal sulcal patterns in patients with FCD of the central region compared with healthy controls. The abnormal sulcal patterns ipsilateral to the FCD and the link between sulcus energy and the FCD location strengthen the interest of sulcal abnormalities in FCD patients. PMID:25822985

Roca, Pauline; Mellerio, Charles; Chassoux, Francine; Rivière, Denis; Cachia, Arnaud; Charron, Sylvain; Lion, Stéphanie; Mangin, Jean-François; Devaux, Bertrand; Meder, Jean-François; Oppenheim, Catherine

2015-01-01

180

AphidBase: A centralized bioinformatic resource for annotation of the pea aphid genome  

PubMed Central

AphidBase is a centralized bioinformatic resource that was developed to facilitate community annotation of the pea aphid genome by the International Aphid Genomics Consortium (IAGC). The AphidBase Information System designed to organize and distribute genomic data and annotations for a large international community was constructed using open source software tools from the Generic Model Organism Database (GMOD). The system includes Apollo and GBrowse utilities as well as a wiki, blast search capabilities and a full text search engine. AphidBase strongly supported community cooperation and coordination in the curation of gene models during community annotation of the pea aphid genome. AphidBase can be accessed at http://www.aphidbase.com. PMID:20482635

Legeai, Fabrice; Shigenobu, Shuji; Gauthier, Jean-Pierre; Colbourne, John; Rispe, Claude; Collin, Olivier; Richards, Stephen; Wilson, Alex C. C.; Tagu, Denis

2015-01-01

181

AphidBase: a centralized bioinformatic resource for annotation of the pea aphid genome.  

PubMed

AphidBase is a centralized bioinformatic resource that was developed to facilitate community annotation of the pea aphid genome by the International Aphid Genomics Consortium (IAGC). The AphidBase Information System designed to organize and distribute genomic data and annotations for a large international community was constructed using open source software tools from the Generic Model Organism Database (GMOD). The system includes Apollo and GBrowse utilities as well as a wiki, blast search capabilities and a full text search engine. AphidBase strongly supported community cooperation and coordination in the curation of gene models during community annotation of the pea aphid genome. AphidBase can be accessed at http://www.aphidbase.com. PMID:20482635

Legeai, F; Shigenobu, S; Gauthier, J-P; Colbourne, J; Rispe, C; Collin, O; Richards, S; Wilson, A C C; Murphy, T; Tagu, D

2010-03-01

182

Early Miocene catarrhine dietary behaviour: the influence of the Red Queen Effect on incisor shape and curvature.  

PubMed

The early Miocene catarrhine fossil record of East Africa represents a diverse and extensive adaptive radiation. It is well accepted that these taxa encompass a dietary range similar to extant hominoids, in addition to some potentially novel dietary behaviour. There have been numerous attempts to infer diet for these taxa from patterns of dental allometry and incisor and molar microwear, however, morphometric analyses until now have been restricted to the post-canine dentition. It has already been demonstrated that given the key functional role of the incisors in pre-processing food items prior to mastication, there is a positive correlation between diet and incisal curvature (Deane, A.S., Kremer, E.P., Begun, D.R., 2005. A new approach to quantifying anatomical curvatures using High Resolution Polynomial Curve Fitting (HR-PCF). Am. J. Phys. Anthropol. 128(3), 630-638.; Deane, A.S., 2007. Inferring dietary behaviour for Miocene hominoids: A high-resolution morphometric approach to incisal crown curvature. Ph.D. Dissertation. The University of Toronto.). This study seeks to re-examine existing dietary hypotheses for large-bodied early Miocene fossil catarrhines by contrasting the incisal curvature for these taxa with comparative models derived from prior studies of the correlation between extant hominoid incisor curvature and feeding behaviour. Incisor curvature was quantified for 78 fossil incisors representing seven genera, and the results confirm that early Miocene fossil catarrhines represent a dietary continuum ranging from more folivorous (i.e., Rangwapithecus) to more frugivorous (i.e., Proconsul) diets, as well as novel dietary behaviours that are potentially similar to extant ceboids (i.e., Afropithecus). Additionally, early Miocene fossil catarrhine incisors are less curved than extant hominoid incisors, indicating a general pattern of increasing mesio-distal and labial curvature through time. This pattern of morphological shifting is consistent with the Red Queen Effect (Van Valen, L., 1973. A new evolutionary law. Evol. Theory 1, 1-30), which predicts that taxa that are removed from one another by geological time, although potentially having similar diets, may exhibit differing degrees of a similar dietary adaptation (i.e., differing degrees of incisal curvature). PMID:19285590

Deane, Andrew S

2009-03-01

183

Assessing the ecological base and peak flow of the alpine streams in Central Taiwan  

NASA Astrophysics Data System (ADS)

The ecological base and peak flow are crucial for the assessment and design for habitat rehabilitation and recovery. The amount of discharge affects the aquatic creatures and may severely damage the existence and balance of the community under extreme conditions. Aquatic insects are selected as the target species in this study to evaluate the influence of the discharge and to estimate the ecological base and peak flow. The distribution of the number of species and abundance (density) versus discharge is assessed to define the critical discharge. Two streams located at the alpine area in central Taiwan are selected as the study area to evaluate the base and peak flow. From the preliminary data (Aug 2008 to Dec 2008) collected from one stream Creek C originating from Sitou Area in Central Taiwan shows that the abundance of several species varies with the discharge. The dominate family and genus of aquatic insects is Baetidae (Order Ephemeroptera) and Baetis spp. that accounts for 32.47% and 31.11%, respectively. The Hilsenhoff family biotic index (FBI) shows that the water quality is classified to "Good" and "Very Good" level while the river pollution index (RPI) indicates that the stream is non-polluted. The discharge of base flow interpreted from the 95% curve of duration for the daily discharge is 0.0234 cms. Consistent observations are yet to be collected to yield more accurate result and ecological peak flow in rainy and typhoon seasons.

Wei, C.; Yang, P. S.; Tian, P. L.

2009-04-01

184

Nonsurgical endodontic treatment of a maxillary lateral incisor with dens invaginatus type II: A case report  

PubMed Central

Dens invaginatus is a rare developmental anomaly of teeth with complex root canal system morphology. The present case describes a peg shape maxillary lateral incisor with dens invaginatus (Oehlers type II), necrotic pulp, and an associated large periradicular lesion. Nonsurgical endodontic treatment was performed with the aim of removing the blind sac with diamond bur under the use of operating surgical microscope. The root canal system was obturated with thermoplastic technique. Final restoration was done using composite. The 20-months clinical and radiological follow up revealed an asymptomatic tooth with healing of the periapical pathology; however, for complete healed periradicular lesion more follow up is needed. This case illustrated that a dens invaginatus malformed teeth with a large periradicular lesion can be managed successfully with nonsurgical root canal therapy (NSRCT).

Shadmehr, Elham; Kiaani, Sima; Mahdavian, Parinaz

2015-01-01

185

Long-term Effects of Traumatic Injuries to Incisors and Periodontal Tissues during Childhood  

Microsoft Academic Search

\\u000a Abstract\\u000a \\u000a \\u000a Aim:\\u000a   The purpose of this study was to investigate the incidence\\u000a of dentoalveolar growth disturbances, loss of teeth and esthetic\\u000a impairment after the end of growth following traumatic injuries\\u000a to incisors and periodontal tissues during childhood.\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a Materials and Methods:\\u000a   41 patients having sustained dentoalveolar\\u000a trauma before age 10 and who were now at least aged 16\\u000a years, and a

Susanne Wriedt; Monika Martin; Bilal Al-Nawas; Heiner Wehrbein

2010-01-01

186

The effects of spaceflight on the mineralization of rat incisor dentin  

NASA Technical Reports Server (NTRS)

Specific effects of space flight on dentin formation on the lower incisors of male rats were determined. Data were Fourier analyzed to determine the spectra of chemical growth rhythms. It was found that Calcium and P were more concentrated in the newly forming dentin of the Flight rats than in comparable regions of control tissues. There was no significant difference in the mean S-concentration between the two groups, but the pattern of S-distribution in the recently formed dentin from the Flight rats was different from that in the control group. Sulfur fluctuations in flight animals periodically peak above the irregular background fluctuations, but there are no comparable sulfur peaks across the dentin in the control. It is indicated that spaceflight has measurable effects on dentinogenesis, and may also bear on the problem of the regulatory role of proteoglycans in mineralization and the maturation of mineral and matrix moieties in skeletal tissue.

Simmons, D. J.; Rosenberg, G. D.

1984-01-01

187

Central FPGA-based destination and load control in the LHCb MHz event readout  

NASA Astrophysics Data System (ADS)

The readout strategy of the LHCb experiment is based on complete event readout at 1 MHz. A set of 320 sub-detector readout boards transmit event fragments at total rate of 24.6 MHz at a bandwidth usage of up to 70 GB/s over a commercial switching network based on Gigabit Ethernet to a distributed event building and high-level trigger processing farm with 1470 individual multi-core computer nodes. In the original specifications, the readout was based on a pure push protocol. This paper describes the proposal, implementation, and experience of a non-conventional mixture of a push and a pull protocol, akin to credit-based flow control. An FPGA-based central master module, partly operating at the LHC bunch clock frequency of 40.08 MHz and partly at a double clock speed, is in charge of the entire trigger and readout control from the front-end electronics up to the high-level trigger farm. One FPGA is dedicated to controlling the event fragment packing in the readout boards, the assignment of the farm node destination for each event, and controls the farm load based on an asynchronous pull mechanism from each farm node. This dynamic readout scheme relies on generic event requests and the concept of node credit allowing load control and trigger rate regulation as a function of the global farm load. It also allows the vital task of fast central monitoring and automatic recovery in-flight of failing nodes while maintaining dead-time and event loss at a minimum. This paper demonstrates the strength and suitability of implementing this real-time task for a very large distributed system in an FPGA where no random delays are introduced, and where extreme reliability and accurate event accounting are fundamental requirements. It was in use during the entire commissioning phase of LHCb and has been in faultless operation during the first two years of physics luminosity data taking.

Jacobsson, R.

2012-10-01

188

Central skull base osteomyelitis: new insights and implications for diagnosis and treatment.  

PubMed

Central skull base osteomyelitis (SBO) is a life-threatening disease originating from ear and from sinonasal infections. The intention of this study was to evaluate contemporary trends in etiology, diagnosis, management, and outcome of SBO and to draw the clinician's attention on this probably underestimated disease. Over a 6-year period we performed this systematic study in an academic quaternary medical care and skull base center including 20 patients (mean age 63.7 years) with central SBO, which is one of the largest series from a single center. In contrast to previous studies we explicitly excluded infections limited to malignant external otitis only but did not restrict central SBO to conditions unrelated to aural pathology. Fifteen patients had otogenic and five sinugenic SBO; four patients had fungal or mixed fungal infections. Pre-existing illnesses altering bone vascularization were detected in 70 % of the patients and had a negative effect on the improvement of cranial nerve palsies that were found in 14 patients. In relation, patients with otogenic SBO more often had local and systemic predisposing factors. Contrary to previous studies 16 patients (80 %) underwent surgical therapy and none of our patients died. A meta-analysis of five recent studies was done and compared with our own data and two previous meta-analyses. The present study highlights several important aspects with major implications for diagnosis and treatment of SBO that have not been adequately addressed as yet. In contrast to the restrictive attitude towards surgery in literature we recommend early and radical operative treatment to reduce its mortality. PMID:25381580

Ridder, Gerd J; Breunig, Christine; Kaminsky, Jan; Pfeiffer, Jens

2015-05-01

189

Base Excision Repair in Physiology and Pathology of the Central Nervous System  

PubMed Central

Relatively low levels of antioxidant enzymes and high oxygen metabolism result in formation of numerous oxidized DNA lesions in the tissues of the central nervous system. Accumulation of damage in the DNA, due to continuous genotoxic stress, has been linked to both aging and the development of various neurodegenerative disorders. Different DNA repair pathways have evolved to successfully act on damaged DNA and prevent genomic instability. The predominant and essential DNA repair pathway for the removal of small DNA base lesions is base excision repair (BER). In this review we will discuss the current knowledge on the involvement of BER proteins in the maintenance of genetic stability in different brain regions and how changes in the levels of these proteins contribute to aging and the onset of neurodegenerative disorders. PMID:23203191

Bosshard, Matthias; Markkanen, Enni; van Loon, Barbara

2012-01-01

190

Mobile devices for community-based REDD+ monitoring: a case study for Central Vietnam.  

PubMed

Monitoring tropical deforestation and forest degradation is one of the central elements for the Reduced Emissions from Deforestation and Forest Degradation in developing countries (REDD+) scheme. Current arrangements for monitoring are based on remote sensing and field measurements. Since monitoring is the periodic process of assessing forest stands properties with respect to reference data, adopting the current REDD+ requirements for implementing monitoring at national levels is a challenging task. Recently, the advancement in Information and Communications Technologies (ICT) and mobile devices has enabled local communities to monitor their forest in a basic resource setting such as no or slow internet connection link, limited power supply, etc. Despite the potential, the use of mobile device system for community based monitoring (CBM) is still exceptional and faces implementation challenges. This paper presents an integrated data collection system based on mobile devices that streamlines the community-based forest monitoring data collection, transmission and visualization process. This paper also assesses the accuracy and reliability of CBM data and proposes a way to fit them into national REDD+ Monitoring, Reporting and Verification (MRV) scheme. The system performance is evaluated at Tra Bui commune, Quang Nam province, Central Vietnam, where forest carbon and change activities were tracked. The results show that the local community is able to provide data with accuracy comparable to expert measurements (index of agreement greater than 0.88), but against lower costs. Furthermore, the results confirm that communities are more effective to monitor small scale forest degradation due to subsistence fuel wood collection and selective logging, than high resolution remote sensing SPOT imagery. PMID:23344371

Pratihast, Arun Kumar; Herold, Martin; Avitabile, Valerio; de Bruin, Sytze; Bartholomeus, Harm; Souza, Carlos M; Ribbe, Lars

2012-01-01

191

Mobile Devices for Community-Based REDD+ Monitoring: A Case Study for Central Vietnam  

PubMed Central

Monitoring tropical deforestation and forest degradation is one of the central elements for the Reduced Emissions from Deforestation and Forest Degradation in developing countries (REDD+) scheme. Current arrangements for monitoring are based on remote sensing and field measurements. Since monitoring is the periodic process of assessing forest stands properties with respect to reference data, adopting the current REDD+ requirements for implementing monitoring at national levels is a challenging task. Recently, the advancement in Information and Communications Technologies (ICT) and mobile devices has enabled local communities to monitor their forest in a basic resource setting such as no or slow internet connection link, limited power supply, etc. Despite the potential, the use of mobile device system for community based monitoring (CBM) is still exceptional and faces implementation challenges. This paper presents an integrated data collection system based on mobile devices that streamlines the community-based forest monitoring data collection, transmission and visualization process. This paper also assesses the accuracy and reliability of CBM data and proposes a way to fit them into national REDD+ Monitoring, Reporting and Verification (MRV) scheme. The system performance is evaluated at Tra Bui commune, Quang Nam province, Central Vietnam, where forest carbon and change activities were tracked. The results show that the local community is able to provide data with accuracy comparable to expert measurements (index of agreement greater than 0.88), but against lower costs. Furthermore, the results confirm that communities are more effective to monitor small scale forest degradation due to subsistence fuel wood collection and selective logging, than high resolution remote sensing SPOT imagery. PMID:23344371

Pratihast, Arun Kumar; Herold, Martin; Avitabile, Valerio; de Bruin, Sytze; Bartholomeus, Harm; Souza, Carlos M.; Ribbe, Lars

2013-01-01

192

A Comparison of a Centralized Versus De-centralized Recruitment Schema in Two Community-Based Participatory Research Studies for Cancer Prevention.  

PubMed

Use of community-based participatory research (CBPR) approaches is increasing with the goal of making more meaningful and impactful advances in eliminating cancer-related health disparities. While many reports have espoused its advantages, few investigations have focused on comparing CBPR-oriented recruitment and retention. Consequently, the purpose of this analysis was to report and compare two different CBPR approaches in two cancer prevention studies. We utilized frequencies and Chi-squared tests to compare and contrast subject recruitment and retention for two studies that incorporated a randomized, controlled intervention design of a dietary and physical activity intervention among African Americans (AA). One study utilized a de-centralized approach to recruitment in which primary responsibility for recruitment was assigned to the general AA community of various church partners whereas the other incorporated a centralized approach to recruitment in which a single lay community individual was hired as research personnel to lead recruitment and intervention delivery. Both studies performed equally well for both recruitment and retention (75 and 88 % recruitment rates and 71 and 66 % retention rates) far exceeding those rates traditionally cited for cancer clinical trials (~5 %). The de-centralized approach to retention appeared to result in statistically greater retention for the control participants compared to the centralized approach (77 vs. 51 %, p < 0.01). Consequently, both CBPR approaches appeared to greatly enhance recruitment and retention rates of AA populations. We further note lessons learned and challenges to consider for future research opportunities. PMID:25086566

Adams, Swann Arp; Heiney, Sue P; Brandt, Heather M; Wirth, Michael D; Khan, Samira; Johnson, Hiluv; Davis, Lisa; Wineglass, Cassandra M; Warren-Jones, Tatiana Y; Felder, Tisha M; Drayton, Ruby F; Davis, Briana; Farr, Deeonna E; Hébert, James R

2015-04-01

193

CENTERA: a centralized trust-based efficient routing protocol with authentication for wireless sensor networks.  

PubMed

In this paper, we present CENTERA, a CENtralized Trust-based Efficient Routing protocol with an appropriate authentication scheme for wireless sensor networks (WSN). CENTERA utilizes the more powerful base station (BS) to gather minimal neighbor trust information from nodes and calculate the best routes after isolating different types of "bad" nodes. By periodically accumulating these simple local observations and approximating the nodes' battery lives, the BS draws a global view of the network, calculates three quality metrics-maliciousness, cooperation, and compatibility-and evaluates the Data Trust and Forwarding Trust values of each node. Based on these metrics, the BS isolates "bad", "misbehaving" or malicious nodes for a certain period, and put some nodes on probation. CENTERA increases the node's bad/probation level with repeated "bad" behavior, and decreases it otherwise. Then it uses a very efficient method to distribute the routing information to "good" nodes. Based on its target environment, and if required, CENTERA uses an authentication scheme suitable for severely constrained nodes, ranging from the symmetric RC5 for safe environments under close administration, to pairing-based cryptography (PBC) for hostile environments with a strong attacker model. We simulate CENTERA using TOSSIM and verify its correctness and show some energy calculations. PMID:25648712

Tajeddine, Ayman; Kayssi, Ayman; Chehab, Ali; Elhajj, Imad; Itani, Wassim

2015-01-01

194

Physics-based real time ground motion parameter maps: the Central Mexico example  

NASA Astrophysics Data System (ADS)

We present the use of near real time ground motion simulations in the generation of ground motion parameter maps for Central Mexico. Simple algorithm approaches to predict ground motion parameters of civil protection and risk engineering interest are based on the use of observed instrumental values, reported macroseismic intensities and their correlations, and ground motion prediction equations (GMPEs). A remarkable example of the use of this approach is the worldwide Shakemap generation program of the United States Geological Survey (USGS). Nevertheless, simple approaches rely strongly on the availability of instrumental and macroseismic intensity reports, as well as the accuracy of the GMPEs and the site effect amplification calculation. In regions where information is scarce, the GMPEs, a reference value in a mean sense, provide most of the ground motion information together with site effects amplification using a simple parametric approaches (e.g. the use of Vs30), and have proven to be elusive. Here we propose an approach that includes physics-based ground motion predictions (PBGMP) corrected by instrumental information using a Bayesian Kriging approach (Kitanidis, 1983) and apply it to the central region of Mexico. The method assumes: 1) the availability of a large database of low and high frequency Green's functions developed for the region of interest, using fully three-dimensional and representative one-dimension models, 2) enough real time data to obtain the centroid moment tensor and a slip rate function, and 3) a computational infrastructure that can be used to compute the source parameters and generate broadband synthetics in near real time, which will be combined with recorded instrumental data. By using a recently developed velocity model of Central Mexico and an efficient finite element octree-based implementation we generate a database of source-receiver Green's functions, valid to 0.5 Hz, that covers 160 km x 300 km x 700 km of Mexico, including a large portion of the Pacific Mexican subduction zone. A subset of the velocity and strong ground motion data available in real time is processed to obtain the source parameters to generate broadband ground motions in a dense grid ( 10 km x 10 km cells). These are interpolated later with instrumental values using a Bayesian Kriging method. Peak ground velocity and acceleration, as well as SA (T=0.1, 0.5, 1 and 2s) maps, are generated for a small set of medium to large magnitude Mexican earthquakes (Mw=5 to 7.4). We evaluate each map by comparing against stations not considered in the computation.

Ramirez Guzman, L.; Contreras Ruiz Esparza, M. G.; Quiroz Ramirez, A.; Carrillo Lucia, M. A.; Perez Yanez, C.

2013-12-01

195

Holocene climate variability in lake Sonkul sediments (Kyrgyzstan, Central Asia) based on vegetation changes  

NASA Astrophysics Data System (ADS)

Western Central Asia, as a remote intracontinental setting located far from oceanic influences, is a key place for high-resolution paleoclimatic studies because different climate systems interact at different timescales and control the regional climate variability. A multiproxy study (pollen grains, palynofacies, and magnetic susceptibility) was conducted on Holocene sediments from the alpine lake Sonkul (3010 m, 41°48'33N / 75°07'38E; Tien Shan, Kyrgyzstan). The combination of sediment core proxies allowed the reconstruction of palaeoenvironmental and palaeoclimatic changes through lake level variations and vegetation dynamics between 8400 and 2000 cal. BP. A high-resolution age model was built on Holocene sediments, constituting one of the most accurate chronologies available in the Central Tien Shan. A quantitative reconstruction of climatic parameters using the "modern analogue vegetation types" (MAV) method was carried out to establish variations in temperature and precipitation patterns during the Holocene as based on variations in fossil pollen assemblages. Between 8400 and 5900 cal. BP, the climate conditions are cold and wet associated with a very low lake level. The Siberian High Pressure (SHP) and the Pacific Summer Monsoon (PSM) are the main mechanisms controlling climatic conditions during the early to mid-Holocene. Between 5900 and 4300 cal. BP, warm and moist conditions characterized the "Mid Holocene Optimum" interval where the combined influence of the Westerlies and the PSM is recorded. Our results reveal that the "Mid Holocene Optimum" period in Lake Sonkul sediments appears to be of shorter duration than in other lakes from the Tibetan plateau. Finally, between 4300 and 2000 cal. BP, the climate becomes persistently arid and warm, as it is nowadays, with a predominant influence of the Westerlies in summer and the SHP in winter. Our results show, therefore, that the lake Sonkul represents an excellent sedimentary archive in Central Asia for high-resolution climatic studies. It allows deciphering, at a high time resolution, the interactions between different climatic systems on environmental dynamics in Central Asia during the Holocene.

Mathis, M.; Sorrel, P.; Klotz, S.; Oberhänsli, H.

2012-04-01

196

Replacement of missing lateral incisors with lithium disilicate glass-ceramic veneer-fixed dental prostheses: a clinical report  

PubMed Central

Key Clinical Message This report describes the use of lithium disilicate glass-ceramic veneer-fixed dental prostheses in replacing congenitally missing maxillary lateral incisors. This kind of prosthesis has an advantage over a lingual-retainer resin-bonded fixed dental prosthesis in its capability of changing the color and shape of the abutment teeth. The prostheses provided an acceptable esthetics and comfort for the patient. PMID:25356269

Bissasu, Sami M; Al-houri, Nabil A

2014-01-01

197

Survival of resin-bonded bridgework provided for post-orthodontic hypodontia patients with missing maxillary lateral incisors  

Microsoft Academic Search

Objective To analyse the clinical performance and factors influencing the survival of resin-bonded bridgework provided for hypodontia patients with missing maxillary lateral incisors, following orthodontic treatment to open, maintain or redistribute the missing tooth space.Design A retrospective analysis of patients treated at a single centre using case notes with all patients invited for review to corroborate findings.Setting Departments of Orthodontics,

R W Wassell; N J Jepson; F S Nohl; M J Garnett

2006-01-01

198

Meteorological factors-based spatio-temporal mapping and predicting malaria in central China.  

PubMed

Despite significant reductions in the overall burden of malaria in the 20th century, this disease still represents a significant public health problem in China, especially in central areas. Understanding the spatio-temporal distribution of malaria is essential in the planning and implementing of effective control measures. In this study, normalized meteorological factors were incorporated in spatio-temporal models. Seven models were established in WinBUGS software by using Bayesian hierarchical models and Markov Chain Monte Carlo methods. M?, M?, and M? modeled separate meteorological factors, and M?, which modeled rainfall performed better than M? and M?, which modeled average temperature and relative humidity, respectively. M? was the best fitting models on the basis of based on deviance information criterion and predicting errors. The results showed that the way rainfall influencing malaria incidence was different from other factors, which could be interpreted as rainfall having a greater influence than other factors. PMID:21896823

Huang, Fang; Zhou, Shuisen; Zhang, Shaosen; Zhang, Hongwei; Li, Weidong

2011-09-01

199

[The role of preprosthetic orthodontics in the interdisciplinary management of congenitally missing maxillary lateral incisors: case report].  

PubMed

The early loss of permanent teeth following trauma or congenital aplasia and agenesia need to be corrected by orthodontic or prosthetic means, sometimes combined with implant therapy. Preprosthetic orthodontic measures are often an integral part of comprehensive oral rehabilitation. The individual aspects of treatment are aimed at optimizing dentofacial esthetics and at improving masticatory function and hygiene potential of prosthetic restorations. The orthodontic solution results usually in different anatomic, functional, and esthetic problems. In the present study the treatment possibilities of two patients with missing upper lateral incisors are presented. In the first case the problem of the missing upper lateral incisors was solved by adhesive bridges, after the fixed appliance orthodontic treatment, where the diasthema medianum was closed, and the upper canines were distalized. In our second case the same problem was solved by inserting implants, with single, metal free crowns in the upper lateral incisor area, after the fixed appliance orthodontic treatment, where the upper canines were distalized, and the bicuspids derotated. Prosthetic and implant procedures are very demanding and require long-term maintenance. Preprosthetic orthodontics will continue to gain significance in future esthetically-functionally oriented dentistry and that its integration into multidisciplinary rehabilitation is often indispensable. PMID:16468482

Vitályos, Géza; Török, Judit; Hegedus, Csaba

2005-12-01

200

Measuring Long-Term Impact Based on Network Centrality: Unraveling Cinematic Citations  

PubMed Central

Traditional measures of success for film, such as box-office revenue and critical acclaim, lack the ability to quantify long-lasting impact and depend on factors that are largely external to the craft itself. With the growing number of films that are being created and large-scale data becoming available through crowd-sourced online platforms, an endogenous measure of success that is not reliant on manual appraisal is of increasing importance. In this article we propose such a ranking method based on a combination of centrality indices. We apply the method to a network that contains several types of citations between more than 40,000 international feature films. From this network we derive a list of milestone films, which can be considered to constitute the foundations of cinema. In a comparison to various existing lists of ‘greatest’ films, such as personal favourite lists, voting lists, lists of individual experts, and lists deduced from expert polls, the selection of milestone films is more diverse in terms of genres, actors, and main creators. Our results shed light on the potential of a systematic quantitative investigation based on cinematic influences in identifying the most inspiring creations in world cinema. In a broader perspective, we introduce a novel research question to large-scale citation analysis, one of the most intriguing topics that have been at the forefront of scientific enquiries for the past fifty years and have led to the development of various network analytic methods. In doing so, we transfer widely studied approaches from citation analysis to the the newly emerging field of quantification efforts in the arts. The specific contribution of this paper consists in modelling the multidimensional cinematic references as a growing multiplex network and in developing a methodology for the identification of central films in this network. PMID:25295877

Spitz, Andreas; Horvát, Em?ke-Ágnes

2014-01-01

201

Measuring long-term impact based on network centrality: unraveling cinematic citations.  

PubMed

Traditional measures of success for film, such as box-office revenue and critical acclaim, lack the ability to quantify long-lasting impact and depend on factors that are largely external to the craft itself. With the growing number of films that are being created and large-scale data becoming available through crowd-sourced online platforms, an endogenous measure of success that is not reliant on manual appraisal is of increasing importance. In this article we propose such a ranking method based on a combination of centrality indices. We apply the method to a network that contains several types of citations between more than 40,000 international feature films. From this network we derive a list of milestone films, which can be considered to constitute the foundations of cinema. In a comparison to various existing lists of 'greatest' films, such as personal favourite lists, voting lists, lists of individual experts, and lists deduced from expert polls, the selection of milestone films is more diverse in terms of genres, actors, and main creators. Our results shed light on the potential of a systematic quantitative investigation based on cinematic influences in identifying the most inspiring creations in world cinema. In a broader perspective, we introduce a novel research question to large-scale citation analysis, one of the most intriguing topics that have been at the forefront of scientific enquiries for the past fifty years and have led to the development of various network analytic methods. In doing so, we transfer widely studied approaches from citation analysis to the the newly emerging field of quantification efforts in the arts. The specific contribution of this paper consists in modelling the multidimensional cinematic references as a growing multiplex network and in developing a methodology for the identification of central films in this network. PMID:25295877

Spitz, Andreas; Horvát, Em?ke-Ágnes

2014-01-01

202

Genes Expressed in Dental Enamel Development Are Associated with Molar-Incisor Hypomineralization  

PubMed Central

Genetic disturbances during dental development influence variation of number and shape of the dentition. In this study, we tested if genetic variation in enamel formation genes is associated with molar-incisor hypomineralization (MIH), also taking into consideration caries experience. DNA samples from 163 cases with MIH and 82 unaffected controls from Turkey, and 71 cases with MIH and 89 unaffected controls from Brazil were studied. Eleven markers in five genes [ameloblastin (AMBN), amelogenin (AMELX), enamelin (ENAM), tuftelin (TUFT1), and tuftelin-interacting protein 11 (TFIP11)] were genotyped by the TaqMan method. Chi-square was used to compare allele and genotype frequencies between cases with MIH and controls. In the Brazilian data, distinct caries experience within the MIH group was also tested for association with genetic variation in enamel formation genes. The ENAM rs3796704 marker was associated with MIH in both populations (Brazil: p=0.03; OR=0.28; 95% C.I.=0.06–1.0; Turkey: p=1.22e–012; OR=17.36; 95% C.I.=5.98–56.78). Associations between TFIP11 (p=0.02), ENAM (p=0.00001), and AMELX (p=0.01) could be seen with caries independent of having MIH or genomic DNA copies of Streptococcus mutans detected by real time PCR in the Brazilian sample. Several genes involved in enamel formation appear to contribute to MIH. PMID:23790503

Jeremias, Fabiano; Koruyucu, Mine; Küchler, Erika C.; Bayram, Merve; Tuna, Elif B.; Deeley, Kathleen; Pierri, Ricardo A.; Souza, Juliana F.; Fragelli, Camila M.B.; Paschoal, Marco A.B.; Gencay, Koray; Seymen, Figen; Caminaga, Raquel M.S.; dos Santos-Pinto, Lourdes; Vieira, Alexandre R.

2013-01-01

203

Effect of high phosphorus diet on tooth microstructure of rodent incisors.  

PubMed

Enamel hypoplasia and disruption of dentinogenesis are the most common abnormalities of development and mineralization of human teeth. Several reports are available in the literature on the influence of dietary calcium on the formation of human and rodent tooth; however, the information about the influence of dietary phosphorus on the tooth formation is scarce. The aim of the present investigation was to examine the chronic effect of high phosphorus diet and improper dietary calcium to phosphorus ratio on the mandibular incisor microstructure in a hystricomorph rodent--Octodon degu--using macroscopic observation, histopathological examination, transmission and scanning electron microscopy. The present study shows that enamel and dentin development is disturbed under high phosphorus diet and improper calcium to phosphorus ratio. Disturbed mineral metabolism resulted in enamel depigmentation, enamel hypoplasia, enamel pitting and altered dentin morphology. The results suggest that more attention should be focused on dietary phosphorus content when facing altered tooth structure in young patients with deciduous or permanent dentition. Furthermore, we showed that degus can be used as an experimental animal model for the study of the developmental teeth disturbances. PMID:21571111

Jekl, Vladimir; Krejcirova, Lenka; Buchtova, Marcela; Knotek, Zdenek

2011-09-01

204

Ontogeny of class II antigen expressing cells in rat incisor pulp.  

PubMed

Class II antigen expressing cells are generally associated with the early phase of the immune response. Dendritic cells and macrophages expressing these cell surface antigens have recently been demonstrated and characterized in the dental pulp. The present study was undertaken to determine when the pulp receives its immunologic defense potential by examining the temporal appearance of class II antigen expressing cells in the rat incisor pulp. Pulp tissue specimens obtained at various time periods from a gestational age of 16 days to 14 wk after birth were examined by immunohistochemistry using O x 6 as a primary antibody and the ABC-technique. Comparisons were made with tissue samples from the spleen, intestine, skin and oral mucosa. At birth, all tissues, except for the pulp, presented cells expressing class II antigen with a dendritic appearance in a number and orientation resembling the mature tissue. A complete distribution of these cells was not seen in the dental pulp until 7 weeks following birth. Data show that the dental pulp acquires its ultimate structural arrangement of immune cells later than other tissues. PMID:1754840

Jontell, M; Jiang, W H; Bergenholtz, G

1991-10-01

205

Incidence of pulp necrosis subsequent to pulp canal obliteration from trauma of permanent incisors.  

PubMed

Little long-term data are available on the frequency by which pulp canal obliteration (PCO) subsequent to trauma leads to pulp necrosis (PN). In this study, 82 concussed, subluxated, extruded, laterally luxated, and intruded permanent incisors presenting with PCO were followed for a period of 7 to 22 yr (mean 16 yr). At final clinical examination, 51% of the observed teeth responded normally to electric pulp testing (EPT). An additional 40% of the teeth although not responding to EPT were clinically and radiographically within normal limits. Yellow discoloration was a frequent finding. During the observation period, periapical bone lesions suggesting PN developed in seven teeth (8.5%). Twenty-yr pulp survival rate was 84%, as determined from life-table calculations. There was no higher frequency of PN in obliterated teeth subjected to caries, new trauma, orthodontic treatment, or complete crown coverage than intact teeth. Although the incidence of PN in teeth displaying PCO seems to increase over the course of time, prophylactic endodontic intervention on a routine basis does not seem justified. PMID:9198446

Robertson, A; Andreasen, F M; Bergenholtz, G; Andreasen, J O; Norén, J G

1996-10-01

206

Relapse of incisor crowding: A visit to the prince of salina  

PubMed Central

The management of the retention period after comprehensive orthodontic treatment is of great importance, as a primary goal of clinician. Considerable controversy still surrounds the problem of stability after the retention period. Many studies analyze factors associated to the presence of crowding or incisor irregularity and find predictive features on its relapse. Most studies have reported little o no correlation between the treatment changes in the biological parameters - clinical, biometric (irregularity index, intermolar width, intercanine width, arch length, overjet, overbite), or cephalometric variables- that ocurred and the posttretament and postretention changes that may predict their future development. This article provides a bibliographical overview on the relapse of dental alignment in treated cases. In a brief historical introduction, the first studies on the long-term stability of orthodontic results are analysed. The article then goes on to assess studies that focus attention on anteroinferior alignment before finally studying relapse of upper crowding. It concludes by making some final comments in the light of the bibliography provided and the differents schools regarding retention needs and methods. Key words:Retention, stability, irregularity, dental alignment. PMID:23229267

Gandía, Jose L.

2013-01-01

207

Zirconia crowns for rehabilitation of decayed primary incisors: an esthetic alternative.  

PubMed

Esthetic management of extensively decayed primary maxillary anterior teeth requiring full coronal coverage restoration is usually challenging to the pediatric dentists especially in very young children. Many esthetic options have been tried over the years each having its own advantages, disadvantages and associated technical, functional or esthetic limitations. Zirconia crowns have provided a treatment alternative to address the esthetic concerns and ease of placement of extra-coronal restorations on primary anterior teeth. The present article presents a case where grossly decayed maxillary primary incisors were restored esthetically and functionally with ready made zirconia crowns (ZIRKIZ, HASS Corp; Korea). After endodontic treatment the decayed teeth were restored with zirconia crowns. Over a 30 months period, the crowns have demonstrated good retention and esthetic results. Dealing with esthetic needs in children with extensive loss of tooth structure, using Zirconia crowns would be practical and successful. The treatment described is simple and effective and represents a promising alternative for rehabilitation of decayed primary teeth. PMID:25631720

Ashima, G; Sarabjot, K Bhatia; Gauba, K; Mittal, H C

2014-01-01

208

Double talon cusps on supernumerary tooth fused to maxillary central incisor: Review of literature and report of case  

PubMed Central

Human tooth development is a continuous process begin at the sixth weeks in utero and extends to about sixth months after birth for the primary dentition and from sixteenth week in utero to late adolescence for permanent dentition. There is no other organ of the human body which takes so long to attain its ultimate morphology as dentition. Several physiologic growth processes participate in the progressive development of the teeth including: initiation, proliferation, histodifferentiation, morphodifferentiation, apposition, calcification, and eruption. Aberrations in different stages of tooth development can result in unique manifestations both in primary and permanent dentitions. The fact that premaxilla is the predilection site for the occurrence of supernumerary teeth, talon cusp, dens invaginatus, and geminated teeth may suggest that the embryological development of premaxilla differ from other sites of the jaws. The dental abnormalities presented in this review are of great concern to dentist and parents because they create clinical, pathological and esthetic problems. Dental practitioner should be aware of the clinical sign, associated problems and treatment options for a given case. Key words:Double talon cusps, fusion, supernumerary, case report. PMID:25593664

2014-01-01

209

Situational Lightning Climatologies for Central Florida: Phase IV: Central Florida Flow Regime Based Climatologies of Lightning Probabilities  

NASA Technical Reports Server (NTRS)

The threat of lightning is a daily concern during the warm season in Florida. Research has revealed distinct spatial and temporal distributions of lightning occurrence that are strongly influenced by large-scale atmospheric flow regimes. Previously, the Applied Meteorology Unit (AMU) calculated the gridded lightning climatologies based on seven flow regimes over Florida for 1-, 3- and 6-hr intervals in 5-, 10-, 20-, and 30-NM diameter range rings around the Shuttle Landing Facility (SLF) and eight other airfields in the National Weather Service in Melbourne (NWS MLB) county warning area (CWA). In this update to the work, the AMU recalculated the lightning climatologies for using individual lightning strike data to improve the accuracy of the climatologies. The AMU included all data regardless of flow regime as one of the stratifications, added monthly stratifications, added three years of data to the period of record and used modified flow regimes based work from the AMU's Objective Lightning Probability Forecast Tool, Phase II. The AMU made changes so the 5- and 10-NM radius range rings are consistent with the aviation forecast requirements at NWS MLB, while the 20- and 30-NM radius range rings at the SLF assist the Spaceflight Meteorology Group in making forecasts for weather Flight Rule violations during Shuttle landings. The AMU also updated the graphical user interface with the new data.

Bauman, William H., III

2009-01-01

210

Assessing the ecological base flow in an experimental watershed of Central Taiwan  

NASA Astrophysics Data System (ADS)

The ecological base flow is crucial for the assessment and design for habitat rehabilitation and recovery. The amount of discharge affects the aquatic creatures and may damage the existence and balance of the community under extreme low conditions. Aquatic insect is selected as the target species in this study to evaluate the influence of the discharge and to estimate the ecological base flow. The distribution of the number of species and abundance (density) versus discharge is assessed to define the critical discharge. A stream located at the alpine area in central Taiwan is selected as the study area to evaluate the base flow. From the preliminary data (Aug 2008 to May 2009) collected from Creek C of Sitou watershed (area: 1.3 km^2) shows that the abundance of several species varies with the discharge. The dominate family and genus of aquatic insects is Baetidae (Order Ephemeroptera) and Baetis spp. that accounts for 26.3 and 17.2 %, respectively. The Hilsenhoff family biotic index (FBI) shows that the water quality is classified to "Excellent" and "Good" level while the EPT Index (Index of three orders: Ephemeroptera, Plecoptera, and Trichoptera) indicates that the stream is non-polluted. The discharge of base flow interpreted from the 90%, 95% and 96% curve of duration for the daily discharge is 0.1582, 0.0476 and 0.0378 cms; the threshold value evaluated by curve of abundance vs. discharge is 0.0154 cms. Consistent observations are yet to be collected to yield more accurate results.

Wei, Chiang; Yang, Ping-Shih; Tian, Pei-Ling

2010-05-01

211

Precipitation frequency analysis based on regional climate simulations in Central Alberta  

NASA Astrophysics Data System (ADS)

A Regional Climate Model (RCM), MM5 (the Fifth Generation Pennsylvania State University/National Center for Atmospheric Research mesoscale model), is used to simulate summer precipitation in Central Alberta. MM5 was set up with a one-way, three-domain nested framework, with domain resolutions of 27, 9, and 3 km, respectively, and forced with ERA-Interim reanalysis data of ECMWF (European Centre for Medium-Range Weather Forecasts). The objective is to develop high resolution, grid-based Intensity-Duration-Frequency (IDF) curves based on the simulated annual maximums of precipitation (AMP) data for durations ranging from 15-min to 24-h. The performance of MM5 was assessed in terms of simulated rainfall intensity, precipitable water, and 2-m air temperature. Next, the grid-based IDF curves derived from MM5 were compared to IDF curves derived from six RCMs of the North American Regional Climate Change Assessment Program (NARCCAP) set up with 50-km grids, driven with NCEP-DOE (National Centers for Environmental Prediction-Department of Energy) Reanalysis II data, and regional IDF curves derived from observed rain gauge data (RG-IDF). The analyzed results indicate that 6-h simulated precipitable water and 2-m temperature agree well with the ERA-Interim reanalysis data. However, compared to RG-IDF curves, IDF curves based on simulated precipitation data of MM5 are overestimated especially for IDF curves of 2-year return period. In contract, IDF curves developed from NARCCAP data suffer from under-estimation and differ more from RG-IDF curves than the MM5 IDF curves. The over-estimation of IDF curves of MM5 was corrected by a quantile-based, bias correction method. By dynamically downscale the ERA-Interim and after bias correction, it is possible to develop IDF curves useful for regions with limited or no rain gauge data. This estimation process can be further extended to predict future grid-based IDF curves subjected to possible climate change impacts based on climate change projections of GCMs (general circulation models) of IPCC (Intergovernmental Panel on Climate Change).

Kuo, Chun-Chao; Gan, Thian Yew; Hanrahan, Janel L.

2014-03-01

212

Characteristics and Composition of Atmospheric Aerosols in Phimai, Central Thailand During BASE-ASIA  

NASA Technical Reports Server (NTRS)

Popular summary: Atmospheric aerosols play an important role in the Earth's climate system, and can also have adverse effects on air quality and human health. The environmental impacts of aerosols, on the other hand, are highly regional, since their temporal/spatial distribution is inhomogeneous and highly depends on the regional emission sources. To better understand the effects of aerosols, intensive field experiments are necessary to characterize the chemical and physical properties on a region-by-region basis. From late February to early May in 2006, NASA/GSFC's SMARTLabs facility was deployed at a rural site in central Thailand, Southeast Asia, to conduct a field experiment dubbed BASE-ASIA (Biomass-burning Aerosols in South East-Asia: Smoke Impact Assessment). The group was joined by scientists from the University of Hawaii and other regional institutes. Comprehensive measurements were made during the experiment, including aerosol chemical composition, optical and microphysical properties, as well as surface energetics and local . meteorology. This study analyzes part of the data from the BASE-ASIA experiment. It was found that, even for the relatively remote rural site, the aerosol loading was still substantial. Besides agricultural burning in the area, industrial pollution near the Bangkok metropolitan area, about 200 km southeast of the site, and even long-range transport from China, also contribute to the area's aerosol loading. The results indicate that aerosol pollution has developed into a regional problem for northern Indochina, and may become more severe as the region's population and economy continue to grow. Abstract: Comprehensive measurements of atmospheric aerosols were made in Phimai, central Thailand (15.l83 N, 102.565 E, elevation: 206 m) during the BASE-ASIA field experiment from late February to early May in 2006. The observed aerosol loading was sizable for this rural site (mean aerosol scattering: 108 +/- 64 Mm(exp -1); absorption: 15 +/- 8 Mm(exp -1); PM(sub 10) concentration: 33 +/- 17 miro-g/ cubic m and dominated by submicron particles. Major aerosol compounds included carbonaceous (OC: 9.5 +/- 3.6miro-g/ cubic m; EC: 2.0 2.3 miro-g/ cubic m and secondary species (SO4(2-): 6.4 +/- 3.7 miro-g/ cubic m, NH4(+): 2.2 +/- 1.3 miro-g/ cubic m). While the site was seldom under the direct influence of large forest fires to its north, agricultural fires were ubiquitous during the experiment, as suggested by the substantial concentration of K+ (0.56 +/- 0.33 micro-g/ cubic m). Besides biomass burning, aerosols in Phimai during the experiment were also strongly influenced by industrial and vehicular emissions from the Bangkok metropolitan region and long-range transport from southern China. High humidity played an important role in determining the aerosol composition and properties in the region. Sulfate was primarily formed via aqueous phase reactions, and hygroscopic growth could enhance the aerosol light scattering by up to 60%, at the typical morning RH level of 85%. The aerosol single scattering albedo demonstrated distinct diurnal variation, ranging from 0.86 +/- 0.04 in the evening to 0.92 +/- 0.02 in the morning. This experiment marks the first time such comprehensive characterization of aerosols was made for rural central Thailand. Our results indicate that aerosol pollution has developed into a regional problem for northern Indochina, and may become more severe as the region's population and economy continue to grow.

Li, Can; Tsay, Si-Chee; Hsu, N. Christina; Kim, Jin Young; Howell, Steven G.; Huebert, Barry J.; Ji, Qiang; Jeong, Myeong-Jae; Wang, Sheng-Hsiang; Hansell, Richard A.; Bell, Shaun W.

2012-01-01

213

Status and future transition of rapid urbanizing landscape in central Western Ghats - CA based approach  

NASA Astrophysics Data System (ADS)

The land use changes in forested landscape are highly complex and dynamic, affected by the natural, socio-economic, cultural, political and other factors. The remote sensing (RS) and geographical information system (GIS) techniques coupled with multi-criteria evaluation functions such as Markov-cellular automata (CA-Markov) model helps in analysing intensity, extent and future forecasting of human activities affecting the terrestrial biosphere. Karwar taluk of Central Western Ghats in Karnataka state, India has seen rapid transitions in its forest cover due to various anthropogenic activities, primarily driven by major industrial activities. A study based on Landsat and IRS derived data along with CA-Markov method has helped in characterizing the patterns and trends of land use changes over a period of 2004-2013, expected transitions was predicted for a set of scenarios through 2013-2022. The analysis reveals the loss of pristine forest cover from 75.51% to 67.36% (1973 to 2013) and increase in agriculture land as well as built-up area of 8.65% (2013), causing impact on local flora and fauna. The other factors driving these changes are the aggregated level of demand for land, local and regional effects of land use activities such as deforestation, improper practices in expansion of agriculture and infrastructure development, deteriorating natural resources availability. The spatio temporal models helped in visualizing on-going changes apart from prediction of likely changes. The CA-Markov based analysis provides us insights into the localized changes impacting these regions and can be useful in developing appropriate mitigation management approaches based on the modelled future impacts. This necessitates immediate measures for minimizing the future impacts.

Bharath, S..; Rajan, K. S.; Ramachandra, T. V.

2014-11-01

214

Elevated serum 25(OH)-vitamin D levels are negatively correlated with molar-incisor hypomineralization.  

PubMed

To date, the precise etiology of molar-incisor hypomineralization (MIH) is uncertain. Vitamin D plays a key role in hard tissue formation. Therefore, this study aimed to analyze the relationship between serum 25-hydroxy-vitamin D (25(OH)D) status and dental health data obtained from 1,048 children in a 10-year follow-up of the Munich GINIplus and LISAplus birth cohorts. The dental examination included the diagnosis of MIH and recording of (non-)cavitated caries lesions in primary and permanent teeth. Serum 25(OH)D concentrations were taken from blood samples of the 10-year investigation and measured with a fully automated, modular system. Different logistic regression and Poisson hurdle models were calculated. MIH was diagnosed in 13.6% of the study population. Approximately 16.4% of the children demonstrated caries-related defects (D3-4MFS > 0). The mean season-adjusted concentration of 25(OH)D was 75.8 nmol/l (standard deviation 22.0 nmol/l). After adjusting for sex, age, body mass index, parental education, equivalent income, and television/personal computer (TV/PC) viewing hours, a 10 nmol/l increase in serum 25(OH)D concentrations was significantly associated with a lower odds ratio of having MIH (OR = 0.89; P = 0.006). Furthermore, higher 25(OH)D values were associated with a lower number of caries-affected permanent teeth. It is concluded that elevated serum 25(OH)D concentrations were associated with better dental health parameters. PMID:25503610

Kühnisch, J; Thiering, E; Kratzsch, J; Heinrich-Weltzien, R; Hickel, R; Heinrich, J

2015-02-01

215

Lithospheric structure of the central asia based on seismotomographic and heat flow data  

NASA Astrophysics Data System (ADS)

Seismic model of the lithosphere was created by means of the tomographic method, called RR-R scheme, which is based on joint use of teleseismic P refracted rays and corresponding PP rays with bounce points located within a study region (Bushenkova, Tychkov, Koulakov, 2002). This scheme allows imaging the deep seismic structure beneath "blank" areas where there are neither recording stations nor earthquakes. The RR-R scheme has been applied to more then 10 000 ray pairs from ISC database to investigate a large region from the North Arctic Ocean to the northern part of China and Mongolia. Thermal thickness of the lithosphere was calculated using steady-state thermal equation with crustal radiogenic heat production exponentially decaying within a layer. Calculation was based on the global heat flow database and more recent data (Tychkov, Koulakov, Bushenkova, Vasilevsky, 2002). Comparison of the seismic and thermal models shows that there are "abnormal" regions where thick "thermal" lithosphere corresponds to thin "seismic" one and vice versa. For example tectonically active Altay and Hangai are characterized by thick thermal and thin seismic lithosphere whereas for the stable Tarim was obtained thick thermal lithosphere and thinned seismic one in the west and vice versa in the east. Paleosoic central Asia lithosphere is now in a maturing stage by means of forming of the rigid depleted mantle part of the lithosphere. Lithosperic rheology of this part depends rather on the way of the forming than on the temperature porfiles that is true for Precambrian continental areas. Fluid concentration in the manle part of the lithosphere is a main feature that determines style of the lithospheric deformation. To create a correct model of the Paleozoic continental lithosphere it is necessary to know a geodynamic situation during its amalgamation. A forming time of the Phanerozoic continental lithosphere can be estimated as a few hundred million years. Heat flow distribution reflects a general tendency for decreasing of this characteristic from south to north. Mountain ranges are characteraized by highest values of the heat flow up to 120 mW/mm in Pamir. Mean observation of the heat flux more than 60 mW/mm was found for Tibet. Heat flow is decreased down to 40 mW/mm in both east and west parts of Tien Shan while twice increasing exists in the central part of this range. In Altai and Hangai, heat flow runs up to 50-60 mW/mm. Kazakh and Siberian ancient precambrean shields marks by low values of the heat flow not more then 40 mW/mm. Most complicate heat flow distribution was found in the sedimentary basins which could be divided on the two groups. The group of the "hot" basins with heat flow more then 60 mW/mm consists of Tarim, Barnaul and Kuzbass. Junggar, Turpan, Qaidam and Gobi belong to "cold" ones with the heat flow of 40 mW/mm. The strenght of the lithosphere is proportional to its thickness so only one restrict to brief description of the lateral lithospheric thickness inhomogeneities. Close fit was obtained between seismic and thermal values of this characteristic for both the Siberian and Kazakh stable regions. The same coincidence was found for Junggar, Mongolia, Tibet and Tien Shan. At the same time thermal lithospheric thickness for Altai exceeds the seismic one. Abnormal thickened thermal lithosphere up to 200 km was obtained for Salair range north to Russian Altai. Thermal lithosphere more than 200 km thickness was found in the west part of Tarim while it decreases twice in the central part of the basin.

Tychkov, S.; Koulakov, I.; Bushenkova, N.; Vasilevsky, A.

2003-04-01

216

Base of Principal Aquifer for the Elkhorn-Loup Model Area, North-Central Nebraska  

USGS Publications Warehouse

In Nebraska, the water managers in the Natural Resources Districts and the Nebraska Department of Natural Resources are concerned with the effect of ground-water withdrawal on the availability of surface water and the long-term effects of ground-water withdrawal on ground- and surface-water resources. In north-central Nebraska, in the Elkhorn and Loup River Basins, ground water is used for irrigation, domestic supply, and public supply; surface water is used in this area for irrigation, recreation, and hydropower production. In recognition of these sometimes competing ground- and surface-water uses in the Elkhorn and Loup River Basins, the U.S. Geological Survey, the Lewis and Clark Natural Resources District, the Lower Elkhorn Natural Resources District, the Lower Loup Natural Resources District, the Lower Niobrara Natural Resources District, the Lower Platte North Natural Resources District, the Middle Niobrara Natural Resources District, the Upper Elkhorn Natural Resources District, and the Upper Loup Natural Resources District agreed to cooperatively study water resources in the Elkhorn and Loup River Basins. The goals of the overall study were to construct and calibrate a regional ground-water flow model of the area and to use that flow model as a tool to assess current and future effects of ground-water irrigation on stream base flow and to help develop long-term water-resource management strategies for this area, hereafter referred to as the Elkhorn-Loup model area. The Elkhorn-Loup model area covers approximately 30,800 square miles, and extends from the Niobrara River in the north to the Platte River in the south. The western boundary of the Elkhorn-Loup model area coincides with the western boundary of the Middle Niobrara, Twin Platte, and Upper Loup Natural Resources Districts; the eastern boundary coincides with the approximate location of the western extent of glacial till in eastern Nebraska. The principal aquifer in most of the Elkhorn-Loup model area is the High Plains aquifer; the principal aquifer in the remaining part of the Elkhorn-Loup model area is an unnamed alluvial aquifer. The upper surface of the geologic units that directly underlie the aquifer is called the 'base of aquifer' in this report. The geologic unit that forms the base of aquifer in the Elkhorn-Loup model area varies by location. The Tertiary-age Brule Formation generally is the base of aquifer in the west; the Cretaceous-age Pierre Shale generally is the base of aquifer in the east. The purpose of this report is to update the altitude and configuration of the base of the principal aquifer in the Elkhorn-Loup model area and a 2-mile buffer area around the Elkhorn-Loup model area, using base-of-aquifer data from test holes, registered water wells, and oil and gas wells within the Elkhorn-Loup model area and a 20-mile buffer area around the Elkhorn-Loup model area that have become available since the publication of earlier maps of the base of aquifer for this area. The base-of-aquifer map is important for the Elkhorn-Loup ground-water flow model because it defines the model's lower boundary. The accuracy of the Elkhorn-Loup ground-water flow model and the accuracy of the model's predictions about the effects of ground-water irrigation on stream base flow are directly related to the accuracy of the model's lower boundary.

McGuire, V.L.; Peterson, S.M.

2008-01-01

217

Evidence-Based Decision Making in School District Central Offices: Toward a Policy and Research Agenda  

ERIC Educational Resources Information Center

District central office administrators increasingly face policy demands to use "evidence" in their decision making. These demands up the ante on education policy researchers and policy makers to better understand what evidence use in district central offices entails and the conditions that may support it. To that end, the authors conducted a…

Honig, Meredith I.; Coburn, Cynthia

2008-01-01

218

Activity-Based Costing and Central Overhead Cost Allocation in Universities: A Case Study  

Microsoft Academic Search

This article examines the development of ABC in university accounting and assesses the contribution it might make to solving the problems associated with central overhead cost allocation systems. A case study using an ABC methodology was developed and applied to library services at the University of Southampton. The results showed substantial differences in the allocation of the central overhead costs

Andrew Goddard; Kean Ooi

1998-01-01

219

The contribution of a central pattern generator in a reflex-based neuromuscular model  

PubMed Central

Although the concept of central pattern generators (CPGs) controlling locomotion in vertebrates is widely accepted, the presence of specialized CPGs in human locomotion is still a matter of debate. An interesting numerical model developed in the 90s’ demonstrated the important role CPGs could play in human locomotion, both in terms of stability against perturbations, and in terms of speed control. Recently, a reflex-based neuro-musculo-skeletal model has been proposed, showing a level of stability to perturbations similar to the previous model, without any CPG components. Although exhibiting striking similarities with human gaits, the lack of CPG makes the control of speed/step length in the model difficult. In this paper, we hypothesize that a CPG component will offer a meaningful way of controlling the locomotion speed. After introducing the CPG component in the reflex model, and taking advantage of the resulting properties, a simple model for gait modulation is presented. The results highlight the advantages of a CPG as feedforward component in terms of gait modulation. PMID:25018712

Dzeladini, Florin; van den Kieboom, Jesse; Ijspeert, Auke

2014-01-01

220

Expansion of Economic Base Analysis: Labor Availability in North-Central New Mexico. Research Report No. 264.  

ERIC Educational Resources Information Center

Estimates of the number of persons willing to commute, at alternative wage rates, to job opportunities in north-central New Mexico have been based on results of basic research in the region and 1970 census data. Expressed willingness to commute and socio-economic characteristics data were accumulated from a regional survey of 643 households. The…

Carruthers, Garrey E.; And Others

221

The Most Proficient Enzyme as the Central Theme in an Integrated, Research-based Biochemistry Laboratory Course  

ERIC Educational Resources Information Center

The enzyme orotidine-5'-monophosphate decarboxylase is an attractive choice for the central theme of an integrated, research-based biochemistry laboratory course. A series of laboratory exercises common to most instructional laboratories, including enzyme assays, protein purification, enzymatic characterization, elementary kinetics, and…

Smiley, Jeffrey A.

2002-01-01

222

New Reforms in the Management of the University: Transition from Centralized to Decentralized (University-Based Management) in Iran  

ERIC Educational Resources Information Center

This article focuses on new reforms in Iran's higher education management system--Transition from centralized to decentralized (University-Based management--UBM). This is an important subject since Iran's Ministry of Science, Research, and Technology (MSRT) has begun to introduce new reforms for the improvement and the enhancement of Iranian…

Mehralizadeh, Y.

2005-01-01

223

Cell-based therapy of chronic degenerative diseases of the central nervous system.  

PubMed

The traditional methods of pharmacotherapy of the degenerative diseases of the central nervous system do not frequently allow one to achieve the desired clinical effect. The fundamentally new approach for the treatment of severe neurological diseases is provided by the methods of biological medicine, in particular, transplantation of a complex of fetal tissues. Cell-based therapy was used to treat patients with multiple sclerosis; ante-, intra- and postnatal lesions; consequences of hemorrhagic and ischemic apoplexies; neuritis of facial nerve; sclerosis; Parkinson's disease; Alzheimer's disease; epilepsy and other types of pathologic process. The source material for obtaining a suspension of cells was the fetuses of allogenic origin. The suspension of brain cells in amounts of up to 1.5 x 10(8) cells and vitality not less than 40% was administered to the patients into liquor spaces using the method of endolumbar puncture. The total number of transplantations was 1900. Practically in all the cases FT was tolerated well. Positive clinical and immunologic changes were observed in the majority of the patients, thus, remission induction (in the patients with the progressive course of multiple sclerosis) for a period over 12 months was registered in 87.5% of the cases. Noteworthy that considerable changes were observed in immunograms: depression of antibody levels to brain-specific proteins, native and denatured DNA; quantitative and qualitative improvement of lymphocyte subpopulation indices, positive changes in the immunoregulatory index. Clinically, in 69% of the cases there was an improvement in more than one neurological defect and a change in the values of the Kurtzke scale towards a decrease by 2-3 points. The conduct of cell therapy with the MS patients under the acute process conditions after liquorosorption allowed the arresting of clinical manifestations and the creation of preconditions for further restoration. The retrobulbar transplantations provided a quick arrest of the retrobulbar neuritis clinical symptoms and in one case an almost complete restoration of vision in the patient with amaurosis (blindness). The remission duration has a marked direct dependence on the number of courses of endolumbar transplantations. Thus, the method of cell therapy with the use of human tissue transplantations is safe and can be used for different neurodegenerative lesions of the central nervous system. The high efficacy of the method suggests the possibility and necessity of using this method as an alternative of classical pharmacological therapy. An important element of cell therapy is the control after the state of the patient's immunity system. PMID:12903713

Pankratov, Ye V; Ivanov, A I; Kolokoltsova, T D; Nechayeva, Ye A; Radayeva, I F; Korochkin, L I; Revischin, A V; Naumov, S A; Khlusovi, I A; Autenshlus, A I

2003-01-01

224

Functional Anatomy of Incisal Biting in Aplodontia rufa and Sciuromorph Rodents – Part 2: Sciuromorphy Is Efficacious for Production of Force at the Incisors  

PubMed Central

The protrogomorph condition of the rodent masticatory apparatus is thought to be present in only one living species, the mountain beaver Aplodontia rufa. The major anatomical difference between protrogomorphs and sciuromorphs is that the relative size of one part of the masseter muscle, the anterior lateral masseter, is much greater in sciuromorphs than in protrogomorphs. The mechanics of force production at the incisors were compared in A. rufa and six sciuromorph rodents. Is the sciuroid masticatory apparatus more effective for production of forces at the incisors during biting than the primitive, protrogomorph condition? To answer this question, three measures of mechanical ability were employed and three hypotheses were tested: (1) the mechanical advantage of the adductor musculature is greater in sciuromorphs than in A. rufa; (2) the relative force produced at the incisors is greater in sciuromorphs than in A. rufa, and (3) the relative amount of force produced that can be used to drive the incisors into an object, is greater in sciuromorphs than in A. rufa. The results demonstrated that the protrogomorph, A. rufa, is not as efficient at generating bite forces at the incisors as the sciuromorphs. PMID:20160427

Druzinsky, Robert E.

2010-01-01

225

Basement structure based on gravity anomaly in the northern Noto peninsula, Central Japan  

NASA Astrophysics Data System (ADS)

Upper crustal block structures are usually defined by using surface information, such as geological and morphological data. The northern Noto Peninsula, central Japan, is divided into four geological block structures from tectonic geomorphologic perspectives (Ota and Hirakawa, 1979). This division is based on the surface crustal movement. To image the geological blocks three-dimensionally, it is necessary to construct a subsurface structure model. Gravity survey can clarify the detailed subsurface structure with dense gravity measurement. From the detailed Bouguer anomalies in the northwestern Noto Peninsula, Honda et al. (2008) suggested that the rupture size of the 2007 Noto Hanto earthquake was constrained by the geological block structures. Hiramatsu et al. (2008) also suggested the active faults on the seafloor, such as the source fault of the 2007 Noto Hanto earthquake plays a major role for the formation of the geological block structures. In this study, we analyze subsurface density structure based on the Bouguer anomaly and estimate the distribution of basement depth in the northern Noto Peninsula. We focus the relationship among the basement depth, the block structures and the active faults on the seafloor and discuss the block movement in the northern Noto Peninsula. We compiled the data measured and published previously (Gravity Database of Southwest Japan, 2001; Geological survey of Japan, 2004; Geographical survey institute of Japan, 2006; The Gravity Research Group in Southwest Japan, 2001; Komazawa and Okuma, 2010; Hokuriku electric power Co. Ltd., undisclosed) and calculated Bouguer anomaly in the northern Noto Peninsula. Based on this Bouguer anomaly, we analyzed subsurface density structures along 13 northeastern-southwestern profiles and 35 northwestern-southeastern profiles with the interval of 2 km using the two dimensional Talwani's method (Talwani et al., 1959). In the analysis, we assumed a density structure with four layers: basement (density is 2670kg/m3), Neocene volcanic rock (density is 2400kg/m3, or 2550kg/m3), Neocene sedimentary rock (density is 2200kg/m3), and Quaternary sedimentary rock (density is 1800kg/m3, or 1500kg/m3) (Honda et al., 2008). To compare our basement model to the geological block structures, we focus on a transition zone of the basement depth. We recognize that two of three geological block boundaries correspond to the transition zones. These boundaries also correspond to the boundary of active fault segments on the seafloor. Therefore, based on the relationship between the source fault of the 2007 Noto Hanto earthquake and the geological block, we suggest that the movement of those geological blocks is possibly controlled by the corresponding active fault segments. However, we find that the other block boundary doesn't correspond to the transition zone.

Mizubayashi, T.; Sawada, A.; Hamada, M.; Hiramatsu, Y.; Honda, R.

2012-12-01

226

Access to facility delivery and caesarean section in north-central Liberia: a cross-sectional community-based study  

PubMed Central

Objective Rural north-central Liberia has one of the world's highest maternal mortality ratios. We studied health facility birthing service utilisation and the motives of women seeking or not seeking facility-based care in north-central Liberia. Design Cross-sectional community-based structured interviews and health facility medical record review. Setting A regional hospital and the surrounding communities in rural north-central Liberia. Participants A convenience sample of 307 women between 15 and 49?years participated in structured interviews. 1031 deliveries performed in the regional hospital were included in the record review. Primary outcomes Delivery within a health facility and caesarean delivery rates were used as indicators of direct utilisation of care and as markers of availability of maternal health services. Results Of 280 interview respondents with a prior childbirth, only 47 (16.8%) delivered their last child in a health facility. Women who did not use formal services cited cost, sudden labour and family tradition or religion as their principal reasons for home delivery. At the regional hospital, the caesarean delivery rate was 35.5%. Conclusions There is an enormous unmet need for maternal health services in north-central Liberia. Greater outreach and referral services as well as community-based education among women, family members and traditional midwives are vital to improve the timely utilisation of care. PMID:23117566

Gartland, Matthew G; Taryor, Victor D; Norman, Andy M; Vermund, Sten H

2012-01-01

227

Remote Sensing Based Biophysical Characterization of Tropical Deciduous Forest in Central India  

NASA Astrophysics Data System (ADS)

The paper reports the measurements of biophysical parameters using field and satellite data over a tropical deciduous forest Kanha National Park (KNP), central India. Field measurement (GBH, LAI, litter, soil moisture) was carried out over ten quadrates of 0.1ha in KNP for characterization of biophysical parameters with specified measurement protocol and sampling. Satellite based remote sensing analysis (LAI, Phenology, and NPP) was carried out using multi date observations of IRS-LISS-III, IMS-1MX, SPOT-VEGETATION and EOS-MODIS instruments. Rank correlation analysis using field data collected in the selected quadrates at KNP showed Sal (Shorea robusta) is dominant forest species followed by Lendia, Jamun (Syzygium cumini), Saja, Harra and Dhawda etc. Field measurement of Sal showed GBH range from 20 cm to 170 cm. Different forest classes such as Sal; Sal mixed with Jamun, Bamboo (Dendrocalamus strictus) etc, including grasslands/scrubland were classified with overall accuracy of 85.56 percent using March, May and October multi spectral data. Sal has distinct growth characteristics (low vegetation growth/ leaf fall in March instead of May) as compared to other vegetation species. As per the Leaf Area Index (LAI) measurement using hemispherical photographs, Sal showed the highest LAI (6.95 m2/m2) during September and lowest LAI (2.63 m2/m2) during March. Overall good agreement (r= 0.79) was found between the LAI generated from LISS-III and MODIS data product. It was observed from SPOT-VEGETATION analysis that NPP varied from 8.4 tC/ha/year (dry deciduous forest) to 14.25 tC/ha/year (Moist deciduous forest) in KNP.

Singh, R. P.; Goroshi, S.; Sharma, N. K.; Bairagi, G. D.; Sharma, R.; Jalil, P.; Jain, A.; Sonakia, A.; Parihar, J. S.

2011-09-01

228

Attenuation Tomography Based on Strong Motion Data: Case Study of Central Honshu Region, Japan  

NASA Astrophysics Data System (ADS)

Three-dimensional frequency dependent S-wave quality factor (Q?(f)) value for the central Honshu region of Japan has been determined in this paper using an algorithm based on inversion of strong motion data. The method of inversion for determination of three-dimensional attenuation coefficients is proposed by H ashida and S himazaki (J Phys Earth. 32, 299-316, 1984) and has been used and modified by J oshi (Curr Sci. 90, 581-585, 2006; Nat Hazards. 43, 129-146, 2007) and J oshi et al. (J. Seismol. 14, 247-272, 2010). Twenty-one earthquakes digitally recorded on strong motion stations of Kik-net network have been used in this work. The magnitude of these earthquake ranges from 3.1 to 4.2 and depth ranging from 5 to 20 km, respectively. The borehole data having high signal to noise ratio and minimum site effect is used in the present work. The attenuation structure is determined by dividing the entire area into twenty-five three-dimensional blocks of uniform thickness having different frequency-dependent shear wave quality factor. Shear wave quality factor values have been determined at frequencies of 2.5, 7.0 and 10 Hz from record in a rectangular grid defined by 35.4°N to 36.4°N and 137.2°E to 138.2°E. The obtained attenuation structure is compared with the available geological features in the region and comparison shows that the obtained structure is capable of resolving important tectonic features present in the area. The proposed attenuation structure is compared with the probabilistic seismic hazard map of the region and shows that it bears some remarkable similarity in the patterns seen in seismic hazard map.

Kumar, Parveen; Joshi, A.; Verma, O. P.

2013-12-01

229

H+-K+-ATPase activity in the rat incisor enamel organ during enamel formation.  

PubMed

The enamel organ of growing rat incisors was perfusion-fixed with a mixture of formaldehyde and glutaraldehyde and processed for ultracytochemical demonstration of ouabain-resistant, K+-stimulated p-nitrophenylphosphatase representing the second dephosphorylative step of H-K-ATPase by use of the one-step lead method. Throughout the stages of amelogenesis, the enzymatic activity was found in the plasma membranes, mitochondrial membranes, and lysosomal structures of the cells of stratum intermedium, papillary layer, and ameloblast layer. Gap junctions and desmosomes between these cells were, however, free of reaction product or showed slight precipitates of reaction. The stellate reticulum and the outer enamel epithelium at the stage of enamel secretion were usually negative for reaction. Although secretory, transition, and ruffle-ended maturation ameloblasts showed enzymatic activity at their basolateral cell surfaces, their distal cell surfaces facing the enamel were always free of reaction product. On the other hand, the smooth-ended maturation ameloblasts seldom showed a positive reaction, except in lysosomes and along their basal cell surfaces. An energy-dispersive X-ray microanalysis of reaction products of H-K-ATPase in unosmicated tissue sections demonstrated that they were composed of lead and phosphorus, which had been released during the dephosphorylation of substrate. In cytochemical controls, the enzymatic activity was completely dependent on substrate and potassium ion, resistant to ouabain and levamisole, and inhibited by nolinium bromide, a specific inhibitor of H-K-ATPase. In addition, inorganic trimetaphosphatase as enzymatic marker of lysosome was localized in dark and pale lysosomes, phagosomes, multivesicular bodies, and ferritin-containing vesicles of the ameloblasts and the cells of stratum intermedium and papillary layer. These membrane-bound structures were also positive for H-K-ATPase reaction. These results suggest that: 1) H-K-ATPase functions to maintain an acidic internal pH of lysosomes in the enamel organ cells; and 2) H-K-ATPase localization in the plasma membranes of enamel organ cells is concerned with efflux of protons derived from cytoplasmic water. PMID:2847591

Sasaki, T; Tadokoro, K; Yanagisawa, T; Higashi, S; Garant, P R

1988-08-01

230

Temperature changes on the root surfaces of mandibular incisors after an 810-nm high-intensity intracanal diode laser irradiation  

NASA Astrophysics Data System (ADS)

Temperature changes caused by laser irradiation can promote damage to the surrounding dental tissues. In this study, we evaluated the temperature changes of recently extracted human mandibular incisors during intracanal irradiation with an 810-nm diode laser at different settings. Fifty mandibular incisors were enlarged up to an apical size of ISO No. 40 file. After the final rinse with 17% ethylenediaminetetraacetic acid, 0.2% lauryl sodium sulfate biologic detergent, and sterile water, samples were irradiated with circular movements from apex to crown through five different settings of output power (1.5, 2.0, 2.5, 3.0, and 3.5 W) in continuous mode. The temperature changes were measured on both sides of the apical and middle root thirds using two thermopar devices. A temperature increase of 7 °C was considered acceptable as a safe threshold when applying the diode laser. Results: The results showed that only 3.5-W output power increased the outer surface temperature above the critical value. Conclusion: The recommended output power can be stipulated as equal to or less than 3 W to avoid overheating during diode laser irradiation on thin dentin walls.

da Fonseca Alvarez, Andrea; Moura-Netto, Cacio; Daliberto Frugoli, Alexandre; Fernando, Casemiro; Correa Aranha, Ana Cecilia; Davidowicz, Harry

2012-01-01

231

Effect of Ligation Method on Maxillary Arch Force/Moment Systems for a Simulated Lingual Incisor Malalignment  

PubMed Central

Introduction: The objectives of this study were to determine whether there is a difference in the magnitude of forces and moments produced by elastic ligation when compared to passive ligation, and whether these forces and moments propagate differently along the arch for the two ligation types. A lingual incisor malalignment was used in this study. Methods: The Orthodontic Simulator (OSIM) was used to quantify the three-dimensional forces and moments applied on the teeth given a lingually displaced incisor. A repeated measures MANOVA was performed to statistically analyze the data. Results: The interaction factor illustrated convincing evidence that there is a difference in maximum force and moment values for all outcome variables between ligation types considering all tooth positions along the arch. The mean differences for FX and FY between ligation types were found to be clinically significant, with values for elastic ligation consistently higher than passive ligation. Conclusion: It was found that the maximum forces and moments produced by elastic ligation are greater than those produced by passive ligation and that the magnitude of this difference for the mesiodistal and buccolingual forces is clinically relevant. Additionally, it was determined that elastic ligation causes forces and moments to propagate further along the arch than passive ligation for all outcome variables. PMID:25400715

Seru, Surbhi; Romanyk, Dan L; Toogood, Roger W; Carey, Jason P; Major, Paul W

2014-01-01

232

An Immature Type II Dens Invaginatus in a Mandibular Lateral Incisor with Talon's Cusp: A Clinical Dilemma to Confront  

PubMed Central

Dens invaginatus (DI) is a malformation of teeth probably resulting from an infolding of the dental papilla during tooth development. DI is classified as type I, II, and III by Oehlers depending on the severity of malformation. The maxillary lateral incisor is the most commonly affected tooth. Structural defects do exist in the depth of the invagination pits, and as a consequence, the early development of caries and the subsequent necrosis of the dental pulp, as well as abscess and cyst formation are clinical implications associated with DI. Occasionally, we can see more than one developmental anomaly occurring in a single tooth. In such cases it becomes important to identify the anomalies and initiate a proper treatment plan for good prognosis. In this paper, an unusual case of DI which clinically presented as a huge talons cusp affecting a mandibular lateral incisor tooth is described. This case report illustrates grinding of the talons cusp followed by nonsurgical endodontic management of dens invaginatus type II with an immature apex and periapical lesions, in which Mineral Trioxide Aggregate (MTA) shows a complete periapical healing with bone formation at the site of the lesions. PMID:24660071

Singal, Deepa; Giri, K. Y.; Keerthi, S. Sruthi

2014-01-01

233

Characterization of Dental Epithelial Stem Cells from the Mouse Incisor with Two-Dimensional and Three-Dimensional Platforms  

PubMed Central

Dental epithelial stem cells (DESCs) drive continuous growth in the adult mouse incisors. To date, a robust system for the primary culture of these cells has not been reported, and little is known about the basic molecular architecture of these cells or the minimal extracellular scaffolding that is necessary to maintain the epithelial stem cell population in an undifferentiated state. We report a method of isolating DESCs from the cervical loop of the mouse mandibular incisor. Cells were viable in a two-dimensional culture system and did not demonstrate preferential proliferation when grown on top of various substrates. Characterization of these cells indicated that E-cadherin, integrin alpha-6, and integrin beta-4 mark the DESCs both in vivo and in vitro. We also grew these cells in a three-dimensional microenvironment and obtained spheres with an epithelial morphology and expression patterns. Insights into the mechanisms of stem cell maintenance in vitro will help lay the groundwork for the successful generation of bioengineered teeth from adult DESCs. PMID:22742471

Chavez, Miquella G.; Yu, Wenli; Biehs, Brian; Harada, Hidemitsu; Snead, Malcolm L.; Lee, Janice S.; Desai, Tejal A.

2013-01-01

234

An Immature Type II Dens Invaginatus in a Mandibular Lateral Incisor with Talon's Cusp: A Clinical Dilemma to Confront.  

PubMed

Dens invaginatus (DI) is a malformation of teeth probably resulting from an infolding of the dental papilla during tooth development. DI is classified as type I, II, and III by Oehlers depending on the severity of malformation. The maxillary lateral incisor is the most commonly affected tooth. Structural defects do exist in the depth of the invagination pits, and as a consequence, the early development of caries and the subsequent necrosis of the dental pulp, as well as abscess and cyst formation are clinical implications associated with DI. Occasionally, we can see more than one developmental anomaly occurring in a single tooth. In such cases it becomes important to identify the anomalies and initiate a proper treatment plan for good prognosis. In this paper, an unusual case of DI which clinically presented as a huge talons cusp affecting a mandibular lateral incisor tooth is described. This case report illustrates grinding of the talons cusp followed by nonsurgical endodontic management of dens invaginatus type II with an immature apex and periapical lesions, in which Mineral Trioxide Aggregate (MTA) shows a complete periapical healing with bone formation at the site of the lesions. PMID:24660071

Gangwar, Anshul; Singal, Deepa; Giri, K Y; Agarwal, Anshita; Keerthi, S Sruthi

2014-01-01

235

Mineral trioxide aggregate apical plug method for the treatment of nonvital immature permanent maxillary incisors: Three case reports  

PubMed Central

Treatment of nonvital immature permanent teeth with calcium-hydroxide is associated with some difficulties such as weakened tooth fracture, root canal reinfection and long treatment time. Mineral trioxide aggregate (MTA) apical plug method is an alternative treatment option for open apices, and has gained popularity in the recent times. In this case report, we have attempted to present successful treatment of three maxillary incisors with open apices and periapical lesions with MTA. After preparing the access cavity, the working length was determined. The root canals were irrigated with 2.5% Sodium hypochlorite (NaOCl) and disinfected with calcium-hydroxide for two weeks. MTA was then placed in the apical 3 millimeters of the root canal. The remaining part of the root canal was filled with gutta-percha and the coronal restoration was finished with composite resin. After six months the radiographic examination showed a decrease of periapical lesions. At a 1-year and 18-months follow up, radiological and clinical successful healing of the incisor teeth was seen. MTA seems as an effective material for the apical plug method for the treatment of nonvital immature permanent teeth with open apices. PMID:22368340

Güne?, Betül; Aydinbelge, Hale Ari

2012-01-01

236

Bmi1 represses Ink4a/Arf and Hox genes to regulate stem cells in the rodent incisor  

PubMed Central

The polycomb group gene Bmi1 is required for maintenance of adult stem cells in many organs1, 2. Inactivation of Bmi1 leads to impaired stem cell self-renewal due to deregulated gene expression. One critical target of BMI1 is Ink4a/Arf, which encodes the cell cycle inhibitors p16ink4a and p19Arf3. However, deletion of Ink4a/Arf only partially rescues Bmi1 null phenotypes4, indicating that other important targets of BMI1 exist. Here, using the continuously-growing mouse incisor as a model system, we report that Bmi1 is expressed by incisor stem cells and that deletion of Bmi1 resulted in fewer stem cells, perturbed gene expression, and defective enamel production. Transcriptional profiling revealed that Hox expression is normally repressed by BMI1 in the adult, and functional assays demonstrated that BMI1-mediated repression of Hox genes preserves the undifferentiated state of stem cells. As Hox gene upregulation has also been reported in other systems when Bmi1 is inactivated1, 2, 5–7, our findings point to a general mechanism whereby BMI1-mediated repression of Hox genes is required for the maintenance of adult stem cells and for prevention of inappropriate differentiation. PMID:23728424

Biehs, Brian; Hu, Jimmy Kuang-Hsien; Strauli, Nicolas B.; Sangiorgi, Eugenio; Jung, Heekyung; Heber, Ralf-Peter; Ho, Sunita; Goodwin, Alice F.; Dasen, Jeremy S.; Capecchi, Mario R.; Klein, Ophir D.

2013-01-01

237

Central giant cell granuloma mimicking an adenomatoid odontogenic tumor.  

PubMed

Central giant cell granulomas are non-neoplastic lesions of unknown etiology. They affect females more than males with the mandibular anterior region being the most common site of occurrence. Clinically central giant cell granulomas present as asymptomatic, expansile swellings causing deviation of associated teeth. Radiologically they usually presents as multilocular lesions causing expansion or perforation of cortical bone. Central giant cell granulomas are usually confused as other lesions both clinically and radiologically, and a definitive diagnosis can be made only histologically. We report here a rare case of central giant cell granuloma in association with congenitally missing tooth which was misdiagnosed to be an adenomatoid odontogenic tumor both clinically and radiologically. This case report also highlights yet another unique presentation of central giant cell granulomas that is in association with a congenitally missing maxillary lateral incisor. PMID:22090775

Daryani, Deepak; Gopakumar, R

2011-07-01

238

Direct evidence of central European forest refugia during the last glacial period based on mollusc fossils  

NASA Astrophysics Data System (ADS)

Although there is evidence from molecular studies for the existence of central European last glacial refugia for temperate species, there is still a great lack of direct fossil records to confirm this theory. Here we bring such evidence in the form of fossil shells from twenty strictly forest land snail species, which were recorded in radiocarbon-dated late glacial or older mollusc assemblages of nine non-interrupted mollusc successions situated in the Western Carpathians, and one in the Bohemian Massif. We proposed that molluscs survived the last glacial period in central Europe in isolated small patches of broadleaf forest, which we unequivocally demonstrate for two sites of last glacial maximum age.

Ju?i?ková, Lucie; Horá?ková, Jitka; Ložek, Vojen

2014-07-01

239

Estimation of Evapotranspiration of Almond orchards using Remote Sensing based SEBAL model in Central Valley, California  

NASA Astrophysics Data System (ADS)

Evapotranspiration is one of the main components of the hydrologic cycle and its impact to hydrology, agriculture,forestry and environmental studies is very crucial. SEBAL (Surface Energy Balance Algorithm for Land) is an image-processing model comprised of twenty-five computational sub-models that computes actual evapotranspiration (ETa) and other energy exchanges as a component of energy balance which is used to derive the surface radiation balance equation for the net surface radiation flux (Rn) on a pixel-by-pixel basis. For this study, SEBAL method is applied to Level 1B dataset of visible, near-infrared and thermal infrared radiation channels of MASTER instrument on-board NASA-DC 8 flight. This paper uses the SEBAL method to (1) investigate the spatial distribution property of land surface temperature (Ls), NDVI, and ETa over the San Joaquin valley. (2) Estimate actual evapotranspiration of almond class on pixel-by-pixel basis in the Central valley, California. (3) Comparison of actual Evapotranspiration obtained from SEBAL model with reference evapotranspiration (Eto) using Penman Monteiths method based on the procedures and available data from California Irrigation Management Information System (CIMIS) stations. The results of the regression between extracted land surface temperature, NDVI and, evapotranspiration show negative (-) correlation. On the other hand Ls possessed a slightly stronger negative correlation with the ETa than with NDVI for Almond class. The correlation coefficient of actual ETa estimates from remote sensing with Reference ETo from Penmann Monteith are 0.8571. ETa estimated for almond crop from SEBAL were found to be almost same with the CIMIS_Penman Monteith method with bias of 0.77 mm and mean percentage difference is 0.10%. These results indicate that combination of MASTER data with surface meteorological data could provide an efficient tool for the estimation of regional actual ET used for water resources and irrigation scheduling and management. Keywords: Evapotranspiration, Hydrologic cycle, SEBAL, net surface radiation flux, MASTER, NDVI, Penman Monteith, CIMIS, Surface Temperature

Roy, S.; Ustin, S.; Kefauver, S. C.

2009-12-01

240

A gene expression atlas of the central nervous system based on bacterial artificial chromosomes  

Microsoft Academic Search

The mammalian central nervous system (CNS) contains a remarkable array of neural cells, each with a complex pattern of connections that together generate perceptions and higher brain functions. Here we describe a large-scale screen to create an atlas of CNS gene expression at the cellular level, and to provide a library of verified bacterial artificial chromosome (BAC) vectors and transgenic

Shiaoching Gong; Chen Zheng; Martin L. Doughty; Kasia Losos; Nicholas Didkovsky; Uta B. Schambra; Norma J. Nowak; Alexandra Joyner; Gabrielle Leblanc; Mary E. Hatten; Nathaniel Heintz

2003-01-01

241

Reconstructing spatiotemporal dynamics of Central European natural beech forests: the rule-based forest model BEFORE  

Microsoft Academic Search

Without humans, large areas of central Europe would be covered by forests dominated by beech (Fagus silvatica). The spatiotemporal dynamics of natural beech forests are hence a subject of interest for both forest management and conservation. However, since in most regions there are no longer any natural beech forests, their structure and dynamics cannot routinely be analysed and compared to

Christine Rademacher; Christian Neuert; Volker Grundmann; Christian Wissel; Volker Grimm

2004-01-01

242

Rationale and Strategies for Central Involvement of Educators in Effective School-Based Mental Health Programs  

Microsoft Academic Search

Unfortunately, for many mental health professionals classroom teachers and other educators are, at best, viewed primarily or solely as useful sources of information about a child, and their broader, invaluable roles as members of the “mental health team” are diminished or dismissed. This article examines the conceptual rationale and empirical support for central involvement of educators (especially classroom teachers) in

Carl E. Paternite; Therese Chiara Johnston

2005-01-01

243

Prediction of central nervous system embryonal tumour outcome based on gene expression  

Microsoft Academic Search

Embryonal tumours of the central nervous system (CNS) represent a heterogeneous group of tumours about which little is known biologically, and whose diagnosis, on the basis of morphologic appearance alone, is controversial. Medulloblastomas, for example, are the most common malignant brain tumour of childhood, but their pathogenesis is unknown, their relationship to other embryonal CNS tumours is debated, and patients'

Scott L. Pomeroy; Pablo Tamayo; Michelle Gaasenbeek; Lisa M. Sturla; Michael Angelo; Margaret E. McLaughlin; John Y. H. Kim; Liliana C. Goumnerova; Peter M. Black; Ching Lau; Jeffrey C. Allen; David Zagzag; James M. Olson; Tom Curran; Cynthia Wetmore; Jaclyn A. Biegel; Tomaso Poggio; Shayan Mukherjee; Ryan Rifkin; Andrea Califano; Gustavo Stolovitzky; David N. Louis; Jill P. Mesirov; Eric S. Lander; Todd R. Golub

2002-01-01

244

Modified Centrality Measure Based on Bidirectional Power Flow for Smart and Bulk Power  

E-print Network

, and F. R. Islam, Student Member, IEEE Abstract--A centrality measure has been proposed considering disturbances [4]. In August 1996, a cascading outage occurred in the Western power grids of North America.anwar@student.adfa.edu.au and f.m.islam@student.adfa.edu.au. which affected around 55 million people happened in August 2003 [6

Pota, Himanshu Roy

245

Studying Geology of Central Texas through Web-Based Virtual Field Trips  

Microsoft Academic Search

Each year over 2500 students, mainly non-science majors, take introductory geology classes at the University of Houston. Optional field trips to Central Texas for these classes provide a unique learning opportunity for students to experience geologic concepts in a real world context. The field trips visit Enchanted Rock, Inks Lake, Bee Cave Road, Lion Mountain, and Slaughter Gap. Unfortunately, only

C. Chan; S. D. Khan; J. S. Wellner

2007-01-01

246

The relationship between odontoblasts and pulp capillaries in the process of enamel- and cementum-related dentin formation in rat incisors  

Microsoft Academic Search

The relationship between odontoblasts and pulp capillaries in the process of dentinogenesis was studied in rat lower incisors, both on the labial and lingual sides, using light and transmission electron microscopy. The odontoblasts showed remarkable differences from the apical to the incisal end. Near the apical end of the tooth, “immature odontoblasts”, which were thought to be involved in the

Hayato Ohshima; Shigemitsu Yoshida

1992-01-01

247

Combined use of miniscrews and continuous arch for intrusive root movement of incisors in Class II division 2 with gummy smile.  

PubMed

Adequate intrusion and torque control of the retroclined maxillary incisors are critical for the treatment of Class II division 2 (div2) malocclusion. In addition, anterior retraction via lingual root movement can be challenging. This case report demonstrates a combined use of miniscrews and continuous arch with additional torque for intrusion, retraction, and torque control of maxillary incisors in the Class II div2 with gummy smile. A 20-year-old woman presented with multiple issues, including impacted canine, lip protrusion, prolonged retained mandibular primary molar, and two missing maxillary premolars. In order to improve her facial profile and eliminate the need for prosthetic work, the mandibular primary molar and contralateral premolar were extracted. Two miniscrews were placed at the maxillary buccal alveolar bone to apply the posterosuperior force for retraction of anterior teeth, with additional labial crown torque on the arch wire. The results were the intrusion (4 mm) and lingual root movement (17°) of the maxillary incisors without anchorage loss of maxillary molars, flattening of the Curve of Spee, and Class I molar relation that were maintained after 50 months of retention period. The combined use of miniscrews and continuous arch could be a reliable and effective treatment modality for torque control and intrusion of retroclined maxillary incisors in the Class II div2 patient. PMID:24512532

Kim, Sung-Jin; Kim, Jin-Wook; Choi, Tae-Hyun; Lee, Kee-Joon

2014-09-01

248

Prediction of extreme floods in the eastern Central Andes based on a complex networks approach.  

PubMed

Changing climatic conditions have led to a significant increase in the magnitude and frequency of extreme rainfall events in the Central Andes of South America. These events are spatially extensive and often result in substantial natural hazards for population, economy and ecology. Here we develop a general framework to predict extreme events by introducing the concept of network divergence on directed networks derived from a non-linear synchronization measure. We apply our method to real-time satellite-derived rainfall data and predict more than 60% (90% during El Niño conditions) of rainfall events above the 99th percentile in the Central Andes. In addition to the societal benefits of predicting natural hazards, our study reveals a linkage between polar and tropical regimes as the responsible mechanism: the interplay of northward migrating frontal systems and a low-level wind channel from the western Amazon to the subtropics. PMID:25310906

Boers, N; Bookhagen, B; Barbosa, H M J; Marwan, N; Kurths, J; Marengo, J A

2014-01-01

249

Prediction of extreme floods in the eastern Central Andes based on a complex networks approach  

NASA Astrophysics Data System (ADS)

Changing climatic conditions have led to a significant increase in the magnitude and frequency of extreme rainfall events in the Central Andes of South America. These events are spatially extensive and often result in substantial natural hazards for population, economy and ecology. Here we develop a general framework to predict extreme events by introducing the concept of network divergence on directed networks derived from a non-linear synchronization measure. We apply our method to real-time satellite-derived rainfall data and predict more than 60% (90% during El Niño conditions) of rainfall events above the 99th percentile in the Central Andes. In addition to the societal benefits of predicting natural hazards, our study reveals a linkage between polar and tropical regimes as the responsible mechanism: the interplay of northward migrating frontal systems and a low-level wind channel from the western Amazon to the subtropics.

Boers, N.; Bookhagen, B.; Barbosa, H. M. J.; Marwan, N.; Kurths, J.; Marengo, J. A.

2014-10-01

250

The design of future central receiver power plants based on lessons learned from the Solar One Pilot Plant  

SciTech Connect

The 10-MW{sub e} Solar One Pilot Plant was the world's largest solar central receiver power plant. During its power production years it delivered over 37,000 MWhrs (net) to the utility grid. In this type of electric power generating plant, large sun-tracking mirrors called heliostats reflect and concentrate sunlight onto a receiver mounted on top a of a tower. The receiver transforms the solar energy into thermal energy that heats water, turning it into superheated steam that drives a turbine to generate electricity. The Solar One Pilot Plant successfully demonstrated the feasibility of generating electricity with a solar central receiver power plant. During the initial 2 years the plant was tested and 4 years the plant was operated as a power plant, a great deal of data was collected relating to the efficiency and reliability of the plant's various systems. This paper summarizes these statistics and compares them to goals developed by the US Department of Energy. Based on this comparison, improvements in the design and operation of future central receiver plants are recommended. Research at Sandia National Laboratories and the US utility industry suggests that the next generation of central receiver power plants will use a molten salt heat transfer fluid rather than water/steam. Sandia has recently completed the development of the hardware needed in a molten salt power plant. Use of this new technology is expected to solve many of the performance problems encountered at Solar One. Projections for the energy costs from these future central receiver plants are also presented. For reference, these projections are compared to the current energy costs from the SEGS parabolic trough plants now operating in Southern California.

Kolb, G.J.

1991-01-01

251

The design of future central receiver power plants based on lessons learned from the Solar One Pilot Plant  

NASA Astrophysics Data System (ADS)

The 10-MW(sub e) Solar One Pilot Plant was the world's largest solar central receiver power plant. During its power production years it delivered over 37,000 MWhrs (net) to the utility grid. In this type of electric power generating plant, large sun-tracking mirrors called heliostats reflect and concentrate sunlight onto a receiver mounted on top of a tower. The receiver transforms the solar energy into thermal energy that heats water, turning it into superheated steam that drives a turbine to generate electricity. The Solar One Pilot Plant successfully demonstrated the feasibility of generating electricity with a solar central receiver power plant. During the initial 2 years the plant was tested and 4 years the plant was operated as a power plant, a great deal of data was collected relating to the efficiency and reliability of the plant's various systems. This paper summarizes these statistics and compares them to goals developed by the U.S. Department of Energy. Based on this comparison, improvements in the design and operation of future central receiver plants are recommended. Research at Sandia National Laboratories and the U.S. utility industry suggests that the next generation of central receiver power plants will use a molten salt heat transfer fluid rather than water/steam. Sandia has recently completed the development of the hardware needed in a molten salt power plant. Use of this new technology is expected to solve many of the performance problems encountered at Solar One. Projections for the energy costs from these future central receiver plants are also presented. For reference, these projections are compared to the current energy costs from the SEGS parabolic trough plants now operating in Southern California.

Kolb, G. J.

252

New Structural Interpretation of the Central Confusion Range, Western Utah, Based On Balanced Cross Sections  

NASA Astrophysics Data System (ADS)

The Confusion Range is a topographically low mountain range in the Basin and Range of west-central Utah, located east of and in the hanging wall of the Snake Range core complex. Previous workers have used a gravity sliding model to interpret the Confusion Range as a large structural trough or synclinorium (e.g. Hose, 1977). Based on existing mapping (Hose, 1965; Hintze, 1974) and new field data, we use balanced and restored cross sections to reinterpret the structure of the Confusion Range as an east-vergent fold-and-thrust belt formed during the Sevier Orogeny. The Confusion Range consists of Cambro-Ordovician through Triassic strata, with predominantly thick-bedded, competent carbonate rocks in the lower Paleozoic (lPz) section and incompetent shales and thin-bedded carbonates in the upper Paleozoic (uPz) section. The contrasting mechanical behavior of these stratigraphic sections results in faulted folds within uPz carbonates above detachments in shale-rich units, deforming in response to ramp-flat thrust faulting of the underlying lPz units. East of the axis of the Conger Mountain (Mtn) syncline, we attribute the increase in structural elevation of lPz rocks to a subsurface thrust sheet consisting of lPz strata that advanced eastward via a high-angle ramp from a lower detachment in the Kanosh Shale to an upper detachment in the Pilot Shale. The doubling of lPz strata that resulted continues through the eastern Confusion Range where a series of small-displacement thrust faults comprising the Kings Canyon thrust system gently tilt strata to the west. In the Conger Range, west of the Conger Mtn syncline, our analysis focuses on reinterpreting the geometrically unlikely folding depicted in previous cross sections as more admissible, fault-cored, asymmetric, detached folding. In our interpretation, resistance created by a steeply-dipping thrust ramp in the lPz section west of Conger Mtn resulted in folding of uPz strata into an east-vergent anticline. Continued east-vergent contraction against the ramp resulted in the west-dipping limb of the anticline, consisting of Ely Limestone, developing into an overturned, west-vergent, synclinal backfold detached in the Chainman Shale. Further contraction exceeded the fold capacity of the detachment fold and resulted in the formation of the Browns Wash fault as an east-vergent thrust fault. The Browns Wash fault is a key component in the development of the present structural geometry, emplacing a west-vergent overturned syncline (detachment fold) in the hanging wall against an east-vergent overturned syncline (footwall syncline) in the footwall. Further west, underlying the western Conger Range and Buckskin Hills, lPz strata are exposed in what we interpret to be a ramp anticline overlying a subsurface thrust ramp. This interpretation implies a lateral ramp separating lPz rocks in the Buckskin Hills from uPz rocks exposed in the Knoll Hill anticline to the north. UPz and Mesozoic strata exposed to the west on the edge of Snake Valley were emplaced by a Tertiary west-dipping normal fault that truncated the west limb of the ramp anticline.

Yezerski, D.; Greene, D. C.

2009-12-01

253

Mineral Deposit Data for Epigenetic Base- and Precious-metal and Uranium-thorium Deposits in South-central and Southwestern Montana and Southern and Central Idaho  

USGS Publications Warehouse

Metal deposits spatially associated with the Cretaceous Boulder and Idaho batholiths of southwestern Montana and southern and central Idaho have been exploited since the early 1860s. Au was first discovered in placer deposits; exploitation of vein deposits in bedrock soon followed. In 1865, high-grade Ag vein deposits were discovered and remained economically important until the 1890s. Early high-grade deposits of Au, Ag and Pb were found in the weathered portions of the veins systems. As mining progressed to deeper levels, Ag and Pb grades diminished. Exploration for and development of these vein deposits in this area have continued until the present. A majority of these base- and precious-metal vein deposits are classified as polymetallic veins (PMV) and polymetallic carbonate-replacement (PMR) deposits in this compilation. Porphyry Cu and Mo, epithermal (Au, Ag, Hg and Sb), base- and precious-metal and W skarn, W vein, and U and Th vein deposits are also common in this area. The world-class Butte Cu porphyry and the Butte high-sulfidation Cu vein deposits are in this study area. PMV and PMR deposits are the most numerous in the region and constitute about 85% of the deposit records compiled. Several types of syngenetic/diagenetic sulfide mineral deposits in rocks of the Belt Supergroup or their equivalents are common in the region and they have been the source of a substantial metal production over the last century. These syngenetic deposits and their metamorphosed/structurally remobilized equivalents were not included in this database; therefore, deposits in the Idaho portion of the Coeur d'Alene district and the Idaho Cobalt belt, for example, have not been included because many of them are believed to be of this type.

Klein, T.L.

2004-01-01

254

A 750-year fire history based on lake sediment records in central Yellowstone National Park, USA  

Microsoft Academic Search

A 750-year fire history was reconstructed for the Central Plateau of Yellowstone National Park from the deep-water sediments of five lakes. The charcoal record from a large lake provided a chronology of regional fires. Data from four small lakes were used to study local and extralocal fires. The co-occurrence of abundant charcoal and high magnetic-susceptibility values at the same stratigraphic

Sarah H. Millspaugh; Cathy Whitlock

1995-01-01

255

Pollen-based reconstructions of late Holocene climate from the central and western Canadian Arctic  

Microsoft Academic Search

Two lake-sediment cores from the western and central Canadian Arctic were used to investigate late Holocene climate variability\\u000a in the region. Both cores were analyzed for pollen, organic matter, biogenic silica, and magnetic susceptibility, and were\\u000a dated using a combination of 210Pb and 14C techniques. Core MB01, from southwestern Victoria Island, provides a 2600-year-long record. Fossil pollen percentages, along\\u000a with

Matthew C. Peros; Konrad Gajewski

2009-01-01

256

Development of Multimode Biomimetic Robotic Fish Based on Central Pattern Generator  

Microsoft Academic Search

This paper presents the construction and motion control of a biologically inspired, multi-mode biomimetic robotic fish capable of three-dimensional locomotion. The mechanical configuration and the control system are described. The rhythmic movements of swimming are driven by the biological neural networks, called the central pattern generators (CPGs). The CPGs are modeled as nonlinear oscillators for joints and inter-joint coordination is

Wei Zhao; Junzhi Yu; Yimin Fang; Long Wang

2006-01-01

257

Synthesis and in vitro transfection efficiency of spermine-based cationic lipids with different central core structures and lipophilic tails.  

PubMed

Twelve spermine-based cationic lipids with four different central core structures (di(oxyethyl)amino, di(oxyethyl)amino carboxy, 3-amino-1,2-dioxypropyl and 2-amino-1,3-dioxypropyl) and three hydrophobic tails (lauric acid, myristic acid and palmitic acid) were synthesized. The liposomes containing lipids and DOPE showed moderate to good in vitro DNA delivery into HeLa cells. GFP expression experiments revealed that liposomes composed of lipids with 3-amino-1,2-dioxypropyl as a central core structure exhibited highest transfection efficiency under serum-free condition. Whereas, lipid with 2-amino-1,3-dioxypropyl core structure showed highest transfection under 10% serum condition. Moreover, the liposomes and lipoplexes composted of these cationic lipids exhibited low cytotoxicity. PMID:25556091

Niyomtham, Nattisa; Apiratikul, Nuttapon; Suksen, Kanoknetr; Opanasopit, Praneet; Yingyongnarongkul, Boon-Ek

2015-02-01

258

Cone beam CT as an aid to diagnosing mixed radiopaque radiolucent lesions in the mandibular incisor region.  

PubMed

We present two cases where the identities of mixed radiopaque radiolucent lesions in the lower incisor region were unclear, although the position of the lesions and positive pulp sensitivity tests were suggestive of periapical osseous dysplasia. In the first case, the lesion presented as a solitary round mixed radiopaque radiolucent periapical lesion, suggestive in some images as periapical osseous dysplasia. Cone beam CT (CBCT) provided clear images, which confirmed the diagnosis and, additionally, the images showed evidence of initial lesions associated with other anterior teeth and some destruction of the labial plate, not evident on the conventional radiographs. In the second case, radiopacities were identified within the lesion on conventional radiographs, but CBCT imaging also showed extensive and unexpected perforation of the lingual plate. Such destruction of cortical plates may be a feature of periapical osseous dysplasia, which is not visible in conventional radiography. PMID:25576510

Krishnan, Unni; Al Maslamani, Manal; Moule, Alex J

2015-01-01

259

Depressed eruption rate of the rat maxillary incisor in a drug-induced uncompensated hemolytic state model  

SciTech Connect

Female rats weighing about 180 g were separated into two groups. One group (A) received phenylhydrazine (PHZ) every other day during three weeks (for induction of an uncompensated hemolytic state), while the control group (C) received saline. The evidence for the establishment of the uncompensated hemolytic state was obtained by hematocrit value, reticulocyte count, and red-cell-volume-59Fe uptake. Body-weight gain (which is a measure of overall body growth rate), body-length gain (which is a measure of longitudinal skeletal growth rate), food intake, and maxillary incisor eruption rate (ER) were significantly depressed in rats of group A during the PHZ-injection period, in relation to rats of group C. These results indicate that anemia and/or associated factors depress ER, along with body growth and skeletal growth.

Giglio, M.J.; Sanz, A.M.; Bozzini, C.E. (Univ. of Buenos Aires (Argentina))

1990-03-01

260

Conservation Action Based on Threatened Species Capture Taxonomic and Phylogenetic Richness in Breeding and Wintering Populations of Central Asian Birds  

PubMed Central

Although phylogenetic diversity has been suggested to be relevant from a conservation point of view, its role is still limited in applied nature conservation. Recently, the practice of investing conservation resources based on threatened species was identified as a reason for the slow integration of phylogenetic diversity in nature conservation planning. One of the main arguments is based on the observation that threatened species are not evenly distributed over the phylogenetic tree. However this argument seems to dismiss the fact that conservation action is a spatially explicit process, and even if threatened species are not evenly distributed over the phylogenetic tree, the occurrence of threatened species could still indicate areas with above average phylogenetic diversity and consequently could protect phylogenetic diversity. Here we aim to study the selection of important bird areas in Central Asia, which were nominated largely based on the presence of threatened bird species. We show that although threatened species occurring in Central Asia do not capture phylogenetically more distinct species than expected by chance, the current spatially explicit conservation approach of selecting important bird areas covers above average taxonomic and phylogenetic diversity of breeding and wintering birds. We conclude that the spatially explicit processes of conservation actions need to be considered in the current discussion of whether new prioritization methods are needed to complement conservation action based on threatened species. PMID:25337861

Schweizer, Manuel; Ayé, Raffael; Kashkarov, Roman; Roth, Tobias

2014-01-01

261

The effect of a single dose of 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) on presecretory ameloblast differentiation in rat incisors.  

PubMed

A single, high dose of HEBP to rats results in a triad of lesions along the mineralizing front of the incisor enamel. One type of lesion is a shallow groove crossing the apical enamel surface. The purpose of this study was to explore the pathogenesis of this "demarcation groove", and to characterize changes in the involved regions of amelogenesis. Rats were given a subcutaneous dose of 10 mg/kg body weight of HEBP and sacrificed by vascular perfusion at intervals ranging from 1 to 36 hours. Mandibular incisors were processed for light and electron microscopy. The region of ameloblasts facing dentin was divided into two subregions: A region of ameloblasts facing unmineralized dentin, comprising a posterior (Aud/p) and an anterior portion (Aud/a), and a region of ameloblasts facing mineralized dentin (Amd). The progressive apical mineralization of the predentin was arrested up to 12 hours after injection of HEBP, while ameloblasts related to already mineralizing dentin continued to differentiate and secrete enamel matrix. At 8 hours the dentin and enamel layers had assumed a common apical border at the start of Amd, marking the position of the future demarcation groove. The length of Aud/p remained constant, Aud/a doubled in length, and Amd was drastically reduced up to 24 hours after injection of HEBP. The normal migration rate of the ameloblasts was unaffected by HEBP. Accumulations of ameloblast secretory products occurred at certain time intervals between the cell apices, but no morphological changes were recorded in the organelles. Most of the changes observed may be indirect in nature resulting from the physico-chemical effect of HEBP on normal mineralization of dentin and enamel. However, further studies are needed to elucidate possible direct cellular effects on ameloblasts. PMID:2128887

Josephsen, K; Fejerskov, O; Baelum, V; Weile, V

1990-12-01

262

Gene expression and immunolocalization of amelogenin in enamel hypoplasia induced by successive injections of bisphosphonate in rat incisors.  

PubMed

Successive injections of 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) in rats induce enamel hypoplasia. To elucidate the pathogenesis of this hypoplasia, male Wistar rats were daily injected with HEBP or physiological saline for 7 days. After the last injection, they were killed under anaesthesia and their maxillary incisors were examined using an in situ hybridization technique and immunohistochemical staining to detect the gene expression and localization of amelogenin protein, respectively. In the HEBP-injected rats, several islets of partially mineralized enamel were present along crown-analogous surface of the incisor in the secretory stage of amelogenesis and enamel-free zones existed between these islets. In situ hybridization demonstrated amelogenin gene expression over the ameloblasts facing the islets of the matrix enamel as well as over those of the enamel-free zones. Immunohistochemical studies using rabbit antiamelogenin antibody revealed positive reaction both in the enamel matrix of the control group and in the islets of enamel matrix of the HEBP-injected group. Some small granules immunoreactive to amelogenin antibody were found in the distal portions of the ameloblasts in the HEBP-injected rats. The results indicate that HEBP does not alter amelogenin gene expression over ameloblasts, or the protein's existence in enamel matrix. There appeared to be some accumulation of amelogenin in the HEBP-treated ameloblasts. It is therefore suggested that the enamel hypoplasia in this experiment may not be due to a disturbance in amelogenin synthesis but to a disturbance in a later process, presumably of protein secretion. PMID:10761874

Yamada, Y; Fuangtharnthip, P; Tamura, Y; Takagi, Y; Ohya, K

2000-03-01

263

The beaver Anchitheriomys from the Miocene of Central Europe  

SciTech Connect

New finds of teeth and mandibles of Anchitheriomys from the Hambach opencast lignite mine in Northwest Germany and the first detailed descriptions of other mandibles from South Germany and Switzerland allow a review of the Central European specimens of this rare beaver genus. The metric variation of cheek teeth and especially the great differences in dimensions of incisors can be much better assessed. The observed range in size can be attributed to ontogenetic changes, and all material is assigned to Anchitheriomys suevicus. Stratigraphically, this species is restricted to the early middle Miocene, European Mammalian Neogene biozones MN 5-6.

Stefen, C.; Mors, T. [Museum Tierkunde, Dresden (Germany)

2008-09-15

264

Headset Bluetooth and cell phone based continuous central body temperature measurement system.  

PubMed

The accurate measure of the central temperature is a very important physiologic indicator in several clinical applications, namely, in the characterization and diagnosis of sleep disorders. In this paper a simple system is described to continuously measure the body temperature at the ear. An electronic temperature sensor is coupled to the microphone of a common commercial auricular Bluetooth device that sends the temperature measurements to a mobile phone to which is paired. The measurements are stored at the mobile phone and periodically sent to a medical facility by email or SMS (short messaging service). PMID:21095713

Sanches, J Miguel; Pereira, Bruno; Paiva, Teresa

2010-01-01

265

Sustainability and Cost of a Community-Based Strategy Against Aedes aegypti in Northern and Central Vietnam  

PubMed Central

We previously reported a new community-based mosquito control that resulted in the elimination of Aedes aegypti in 40 of 46 communes in northern and central Vietnam. During 2007 and 2008, we revisited Nam Dinh and Khanh Hoa provinces in northern and central Vietnam, respectively, to evaluate whether or not these programs were still being maintained 7 years and 4.5 years after formal project activities had ceased, respectively. Using a previously published sustainability framework, we compared 13 criteria from Tho Nghiep commune in Nam Dinh where the local community had adopted our community-based project model using Mesocyclops from 2001. These data were compared against a formal project commune, Xuan Phong, where our successful intervention activities had ceased in 2000 and four communes operating under the National Dengue Control Program with data available. In Khanh Hoa province, we compared 2008 data at Ninh Xuan commune with data at project completion in 2003 and benchmarked these, where possible, against an untreated control commune, Ninh Binh, where few control activities had been undertaken. The three communes where the above community-based strategy had been adopted were rated as well-sustained with annual recurrent total costs (direct and indirect) of $0.28–0.89 international dollars per person. PMID:20439962

Kay, Brian H.; Tuyet Hanh, Tran T.; Le, Nguyen Hoang; Quy, Tran Minh; Nam, Vu Sinh; Hang, Phan V. D.; Yen, Nguyen Thi; Hill, Peter S.; Vos, Theo; Ryan, Peter A.

2010-01-01

266

Central Skull Base Osteomyelitis in Patients without Otitis Externa: Imaging Findings  

Microsoft Academic Search

BACKGROUND AND PURPOSE: Skull base osteomyelitis typically arises as a complication of ear infection in older diabetic patients, involves the temporal bone, and has Pseudomonas aeruginosa as the usual pathogen. Atypical skull base osteomyelitis arising from the sphenoid or occipital bones without associated external otitis occurs much less frequently and initially may have headache as the only symptom. The purpose

Patrick C. Chang; Nancy J. Fischbein; Roy A. Holliday

267

PHYSICS AND CONTROL OF ELMING H-MODE NEGATIVE CENTRAL SHEAR ADVANCED TOKAMAK SCENARIO BASED ON EXPERIMENTAL PROFILES FOR ITER  

SciTech Connect

A271 PHYSICS AND CONTROL OF ELMING H-MODE NEGATIVE CENTRAL SHEAR ADVANCED TOKAMAK SCENARIO BASED ON EXPERIMENTAL PROFILES FOR ITER. Key DIII-D AT experimental and modeling results are applied to examine the physics and control issues for ITER to operate in a negative central shear (NCS) AT scenario. The effects of a finite edge pressure pedestal and current density are included based on the DIII-D experimental profiles. Ideal and resistive stability analyses indicate that feedback control of resistive wall modes by rotational drive or flux conserving intelligent coils is crucial for these AT configurations to operate at attractive {beta}{sub N} values in the range of 3.0-3.5. Vertical stability and halo current analyses show that reliable disruption mitigation is essential and mitigation control using an impurity gas can significantly reduce the local mechanical stress to an acceptable level. Core transport and turbulence analyses demonstrate that control of the rotational shear profile is essential to maintain the good confinement necessary for high {beta}. Consideration of edge stability and core transport suggests that a sufficiently wide pedestal is necessary for the projected fusion performance. Heat flux analyses indicate that with core-only radiation enhancement the outboard peak divertor heat load is near the design limit of 10 MW/m{sup 2}

LAO,LL; CHAN,VS; EVANS,TE; HUMPHREYS,DA; LEUER,JA; MAHDAVI,MA; PETRIE,TW; SNYDER,PB; STJOHN,HE; STAEBLER,GM; STAMBAUGH,RD; TAYLOR,TS; TURNBULL,AD; WEST,WP; BRENNAN,DP

2002-11-01

268

Security of Business to Business and Business to Customer Software Applications based on the Central Dogma of Molecular Biology (CDMB) and evolutionary models  

Microsoft Academic Search

The development, implementation and testing for Security of Business to Business and Business to Customer Software Applications System is based on the Central Dogma of Molecular Biology (CDMB), where we derive DNA Cryptographic Keys based on evolutionary models as public-key algorithms are based on mathematical functions rather than on substitution and permutation involving the use of two separate keys, in

Tatiana Hodorogea; Ionas Szilard Otto

2011-01-01

269

Evidence-based Decision Making: Influences on Central-Office Administrators' Decision-Making Practices  

E-print Network

administrators across the state of Texas were surveyed to obtain information about their evidence-based decision-making practices and the factors that influenced them when making decisions about interventions for their districts. The purpose...

Haecker, Bonnie Minnia

2013-12-05

270

The Generation of Antiphase Oscillations and Synchrony by a Rebound-Based Vertebrate Central Pattern Generator  

PubMed Central

Many neural circuits are capable of generating multiple stereotyped outputs after different sensory inputs or neuromodulation. We have previously identified the central pattern generator (CPG) for Xenopus tadpole swimming that involves antiphase oscillations of activity between the left and right sides. Here we analyze the cellular basis for spontaneous left–right motor synchrony characterized by simultaneous bursting on both sides at twice the swimming frequency. Spontaneous synchrony bouts are rare in most tadpoles, and they instantly emerge from and switch back to swimming, most frequently within the first second after skin stimulation. Analyses show that only neurons that are active during swimming fire action potentials in synchrony, suggesting both output patterns derive from the same neural circuit. The firing of excitatory descending interneurons (dINs) leads that of other types of neurons in synchrony as it does in swimming. During synchrony, the time window between phasic excitation and inhibition is 7.9 ± 1 ms, shorter than that in swimming (41 ± 2.3 ms). The occasional, extra midcycle firing of dINs during swimming may initiate synchrony, and mismatches of timing in the left and right activity can switch synchrony back to swimming. Computer modeling supports these findings by showing that the same neural network, in which reciprocal inhibition mediates rebound firing, can generate both swimming and synchrony without circuit reconfiguration. Modeling also shows that lengthening the time window between phasic excitation and inhibition by increasing dIN synaptic/conduction delay can improve the stability of synchrony. PMID:24760866

Merrison-Hort, Robert; Zhang, Hong-Yan; Borisyuk, Roman

2014-01-01

271

Centralized Monitoring of the Microsoft Windows-based computers of the LHC Experiment Control Systems  

NASA Astrophysics Data System (ADS)

The control system of each of the four major Experiments at the CERN Large Hadron Collider (LHC) is distributed over up to 160 computers running either Linux or Microsoft Windows. A quick response to abnormal situations of the computer infrastructure is crucial to maximize the physics usage. For this reason, a tool was developed to supervise, identify errors and troubleshoot such a large system. Although the monitoring of the performance of the Linux computers and their processes was available since the first versions of the tool, it is only recently that the software package has been extended to provide similar functionality for the nodes running Microsoft Windows as this platform is the most commonly used in the LHC detector control systems. In this paper, the architecture and the functionality of the Windows Management Instrumentation (WMI) client developed to provide centralized monitoring of the nodes running different flavour of the Microsoft platform, as well as the interface to the SCADA software of the control systems are presented. The tool is currently being commissioned by the Experiments and it has already proven to be very efficient optimize the running systems and to detect misbehaving processes or nodes.

Varela Rodriguez, F.

2011-12-01

272

Landslide observation and volume estimation in central Georgia based on L-band InSAR  

NASA Astrophysics Data System (ADS)

The republic of Georgia is a mountainous and tectonically active area that is vulnerable to landslides. Because landslides are one of the most devastating natural hazards, their detection and monitoring is of great importance. In this study we report on a previously unknown landslide in central Georgia near the town of Sachkhere. We used a set of Advanced Land Observation Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) data to generate displacement maps using interferometric synthetic aperture radar (InSAR). We detected a sliding zone of dimensions 2 km north-south by 0.6 km east-west that threatens four villages. We estimated surface displacement of up to ∼30 cm/yr over the sliding body in the satellite line-of-sight (LOS) direction, with the largest displacement occurring after a local tectonic earthquake. We mapped the morphology of the landslide mass by aerial photography and field surveying. We found a complex set of interacting processes, including surface fracturing, shear and normal faults at both the headwall and the sides of the landslide, local landslide velocity changes, earthquake-induced velocity peaks, and loss in toe support due to mining activity. Important implications that are applicable elsewhere can be drawn from this study of coupled processes. We used inverse dislocation modelling to find a possible dislocation plane resembling the landslide basal décollement, and we used that plane to calculate the volume of the landslide. The results suggest a décollement at ∼120 m depth, dipping at ∼10° sub-parallel to the surface, which is indicative of a translational-type landslide.

Nikolaeva, E.; Walter, T. R.; Shirzaei, M.; Zschau, J.

2014-03-01

273

Magmatic occurrences in the Central Arava (southern Israel) based on Geology and Magnetometry  

NASA Astrophysics Data System (ADS)

The Eshet Ridge is located in the Central Arava near Wadi Paran. Geological data were collected using ground magnetic surveys and petrophysical measurements (magnetic susceptibility and density). The goal was to reveal the structure and nature of a concealed magmatic body under the ridge. Integrated gravity and magnetic interpretation together with seismic reflection data (including 2¾ modeling) indicated the presence of a deep-seated basic magmatic intrusion. Occurrence of Fe-mineralized rocks along the ridge supports subsurface data. The magmatic body was intruded in the hard Turonian rocks of the Eshet Ridge. Basic magmatic exposures dating from the Early Miocene were evident along Wadi Ashosh (in the eastern Negev) and its margins 18 km. to the north of the ridge. A new outcrop of basic magmatic intrusion was found southwest of the Tzukim settlement. Magnetic measurements indicated a similarity between their magnetic pattern and the Ashosh basic magmatics, which were dated to 20.4 ± 0.7 Ma. Volcanoclastic tuff pebbles (magnetic susceptibility of around 2-7 * 10-3 SI) surrounded by conglomerate were discovered at two sites in Wadi Demma and Wadi Menuha (streams that drain near the Eshet Ridge and 2 km south of it, respectively). The conglomerates contained mostly limestone, chalk and chert fragments; not more than 5% of which were volcanic pebbles. Two pebbles were dated to 24.4 ± 0.7and 21.5 ± 0.5 Ma. The magmatic outcrops in Wadi Ashosh, the magmatic dyke near Tzukim and the volcanic purple and black pebbles near Wadi Menuha were all dated to the very Late Oligocene-Early Miocene. The magmatic body identified in this study under the Eshet Ridge was termed the Eshet Intrusion and is connected to, and even the source of, all these phenomena.

Hanan, Ginat; Michael, Rybakov; Boris, Shirman; Michael, Lazar

2014-05-01

274

Fingerprint Classification Based on Improved Singular Points Detection and Central Symmetrical Axis  

Microsoft Academic Search

Effective fingerprint classification not only can provide an important index mechanism for large fingerprint database, but also can improve the efficiency and performance of AFIS. At present, because of traditional Poincare method detection more false singular points and weaker anti-noise problem, this paper presents a fingerprint classification method based on continuously directional image and symmetrical axis. Compared with traditional algorithms,

Wang Feng; Chen Yun; Wang Hao; Wang Xiu-you

2009-01-01

275

A GPS-based three-dimensional lightning mapping system: Initial observations in central New Mexico  

Microsoft Academic Search

A GPS-based system has been developed that accurately locates the sources of VHF radiation from lightning discharges in three spatial dimensions and time. The observations are found to reflect the basic charge structure of electrified storms. Observations have also been obtained of a distinct type of energetic discharge referred to as positive bipolar breakdown, recently identified as the source of

W. Rison; R. J. Thomas; P. R. Krehbiel; T. Hamlin; J. Harlin

1999-01-01

276

Assessment of Herbicide Transport in Central Missouri Watersheds Using a Process-Based Index Model  

Technology Transfer Automated Retrieval System (TEKTRAN)

Identification of areas at risk for pesticide loss is a necessary requirement for targeting best management practices (BMPs) to the most vulnerable areas within watersheds. To work toward that goal, a process-based index model was developed to assess relative landscape vulnerability to hydrologic lo...

277

Urokinase-type plasminogen activator mRNA is expressed in normal developing teeth and leads to abnormal incisor enamel in alpha MUPA transgenic mice.  

PubMed

The urokinase-type plasminogen activator (uPA) is a secreted, inducible serine protease implicated in extracellular proteolysis and tissue remodeling. Here we detected uPA mRNA through in situ hybridization in developing molar and incisor teeth of normal mice at multiple sites of the cap and bell developmental stages. The mRNA was confined to epithelial cells, however, was undetectable in ameloblasts or their progenitor preameloblasts and the inner enamel epithelium. Furthermore, mice of five lines of previously described alphaMUPA transgenic mice, carrying a transgene consisting of the uPA cDNA linked downstream from the alphaA-crystallin promoter, overexpressed uPA mRNA in the same epithelial sites. In addition, alphaMUPA mice showed remarkably high levels of uPA mRNA in ameloblasts, however, exclusively in two specific sites late in incisor development. First, at the late secretory stage, but only on sides of the ameloblast layer. Second, in a limited zone of ameloblasts near the incisal end, coinciding with a striking morphological change of the ameloblast layer and the enamel matrix. In adult alphaMUPA mice, the incisor teeth displayed discoloration and tip fragility, and reduction of the outer enamel as determined by scanning electron microscopy. These results suggest that balanced uPA activity could play a role in normal tooth development. The alphaMUPA tooth phenotype demonstrates a remarkable sensitivity to excessive extracellular proteolysis at the incisor maturation stage of amelogenesis. PMID:16604464

Miskin, Ruth; Masos, Tamar; Shoham, Zipi; Williams-Simons, Lisa

2006-04-01

278

Aetiologies of Central Nervous System Infection in Viet Nam: A Prospective Provincial Hospital-Based Descriptive Surveillance Study  

PubMed Central

Background Infectious diseases of the central nervous system (CNS) remain common and life-threatening, especially in developing countries. Knowledge of the aetiological agents responsible for these infections is essential to guide empiric therapy and develop a rational public health policy. To date most data has come from patients admitted to tertiary referral hospitals in Asia and there is limited aetiological data at the provincial hospital level where most patients are seen. Methods We conducted a prospective Provincial Hospital-based descriptive surveillance study in adults and children at thirteen hospitals in central and southern Viet Nam between August 2007– April 2010. The pathogens of CNS infection were confirmed in CSF and blood samples by using classical microbiology, molecular diagnostics and serology. Results We recruited 1241 patients with clinically suspected infection of the CNS. An aetiological agent was identified in 640/1241 (52%) of the patients. The most common pathogens were Streptococcus suis serotype 2 in patients older than 14 years of age (147/617, 24%) and Japanese encephalitis virus in patients less than 14 years old (142/624, 23%). Mycobacterium tuberculosis was confirmed in 34/617 (6%) adult patients and 11/624 (2%) paediatric patients. The acute case fatality rate (CFR) during hospital admission was 73/617 (12%) in adults and to 42/624 (7%) in children. Conclusions Zoonotic bacterial and viral pathogens are the most common causes of CNS infection in adults and children in Viet Nam. PMID:22662232

Ho Dang Trung, Nghia; Le Thi Phuong, Tu; Wolbers, Marcel; Nguyen Van Minh, Hoang; Nguyen Thanh, Vinh; Van, Minh Pham; Thieu, Nga Tran Vu; Le Van, Tan; Song, Diep To; Le Thi, Phuong; Thi Phuong, Thao Nguyen; Van, Cong Bui; Tang, Vu; Ngoc Anh, Tuan Hoang; Nguyen, Dong; Trung, Tien Phan; Thi Nam, Lien Nguyen; Kiem, Hao Tran; Thi Thanh, Tam Nguyen; Campbell, James; Caws, Maxine; Day, Jeremy; de Jong, Menno D.; Van Vinh, Chau Nguyen; Van Doorn, H. Rogier; Tinh, Hien Tran; Farrar, Jeremy; Schultsz, Constance

2012-01-01

279

Knowledge-Based, Central Nervous System (CNS) Lead Selection and Lead Optimization for CNS Drug Discovery  

PubMed Central

The central nervous system (CNS) is the major area that is affected by aging. Alzheimer’s disease (AD), Parkinson’s disease (PD), brain cancer, and stroke are the CNS diseases that will cost trillions of dollars for their treatment. Achievement of appropriate blood–brain barrier (BBB) penetration is often considered a significant hurdle in the CNS drug discovery process. On the other hand, BBB penetration may be a liability for many of the non-CNS drug targets, and a clear understanding of the physicochemical and structural differences between CNS and non-CNS drugs may assist both research areas. Because of the numerous and challenging issues in CNS drug discovery and the low success rates, pharmaceutical companies are beginning to deprioritize their drug discovery efforts in the CNS arena. Prompted by these challenges and to aid in the design of high-quality, efficacious CNS compounds, we analyzed the physicochemical property and the chemical structural profiles of 317 CNS and 626 non-CNS oral drugs. The conclusions derived provide an ideal property profile for lead selection and the property modification strategy during the lead optimization process. A list of substructural units that may be useful for CNS drug design was also provided here. A classification tree was also developed to differentiate between CNS drugs and non-CNS oral drugs. The combined analysis provided the following guidelines for designing high-quality CNS drugs: (i) topological molecular polar surface area of <76 Å2 (25–60 Å2), (ii) at least one (one or two, including one aliphatic amine) nitrogen, (iii) fewer than seven (two to four) linear chains outside of rings, (iv) fewer than three (zero or one) polar hydrogen atoms, (v) volume of 740–970 Å3, (vi) solvent accessible surface area of 460–580 Å2, and (vii) positive QikProp parameter CNS. The ranges within parentheses may be used during lead optimization. One violation to this proposed profile may be acceptable. The chemoinformatics approaches for graphically analyzing multiple properties efficiently are presented. PMID:22267984

2011-01-01

280

A conodont-based standard reference section in central Nevada for the lower Middle Ordovician Whiterockian Series  

USGS Publications Warehouse

Ranges of conodonts in stratigraphic sections at five localities in the Monitor and Antelope ranges of central Nevada are used graphically to assemble a standard reference section for the lower Middle Ordovician Whiterockian Series. The base of the series is officially 0.3 m above the base of the Antelope Valley Limestone in the stratotype in Whiterock Canyon (Monitor Range). The top is the level at which Baltoniodus gerdae makes a brief appearance in an exposure of the Copenhagen Formation on the flanks of Hill 8308 in the western Antelope Range. Graphic compilation of the sections considered in this report also indicates that a level correlative with the base of the Whiterockian Series in the stratotype section is 66 m above the base of the Antelope Valley Limestone in its de facto type section on Martin Ridge in the eastern part of the Monitor Range. Ranges, diversity, and the composition of the conodont faunas differ markedly in lithofacies adjacent to the basal boundary of the series; hence we are unable to identify a single conodont species, in a credible developmental sequence, to serve as biological marker of that boundary.

Sweet, W.C.; Ethington, R.L.; Harris, A.G.

2005-01-01

281

[Effects of 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) on the unimpeded eruption rate and the dental hard tissue formation in rat mandibular incisor].  

PubMed

To understand the mechanism of eruption in continuously growing teeth, the relationship between the rate of eruption and formation of dental hard tissues was examined following administration of 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP), an inhibitor of hard tissue formation. Three experimental groups of rats received daily subcutaneous injections of 9, 18 or 36 mg P of HEBP/kg, respectively, for 7 days. Tetracycline was also injected to mark the dentine in some animals. To maintain an unimpeded state, all four incisors in each rat were shortened repeatedly during the experimental period. Eruption rates of the mandibular incisors were measured by a photographic method. Transverse sections of the mandibles were cut and histological, microradiographic and fluorescent micrographic examinations were done. Significant decreases of the eruption rates were found in all experimental groups following the administration of HEBP. However, differences were not marked among the three experimental groups. It was also shown that matrix formation and calcification of the dentine were markedly inhibited following the administration of HEBP. Matrix formation and calcification of the enamel were also inhibited by the drug administration. It is assumed that the eruption of the rat incisor is not closely associated with the formation of dental hard tissues and their calcification. PMID:2722085

Izumi, T

1989-02-01

282

Distribution of non-collagenous dentin matrix proteins and proteoglycans, and their relation to calcium accumulation in bisphosphonate-affected rat incisors.  

PubMed

It has been reported that multiple injections of 1-hydroxyethylidene- 1,1-bisphosphonate (HEBP) to rats prevent mineralization of incisor dentin, thereby revealing high concentrations of calcium in the non-mineralized matrix of circumpulpal dentin. To identify the molecules responsible for calcium accumulation in circumpulpal dentin matrix, rats were injected daily with HEBP (8 mg P/kg) for 7 d, and the incisors processed for various histochemical and immunohistochemical staining of non-collagenous matrices of dentin. Cuprolinic blue reactions for proteoglycans (PGs) were equally distributed in non-mineralized matrix of mantle and circumpulpal dentin layers. Dentin sialoprotein (DSP) and osteopontin (OPN) immunoreactions were found in non-mineralized circumpulpal dentin matrix, but not in mantle dentin. In normal incisors, however, predentin matrix showing significant DSP immunoreactivity was negative for Ca-GBHA reactions. HEBP-affected, non-mineralized OPN immunopositive bone matrix was also non-reactive for calcium. From these observations, neither PGs, OPN nor DSP appear to be responsible for calcium accumulation in HEBP-affected circumpulpal dentin. Stains-all reactive component, possibly dentin phosphoprotein (DPP), only showed the same distribution as that of Ca-GBHA in both HEBP-affected and normal dentin matrix, implicating a possible contribution of DPP to calcium accumulation in circumpulpal dentin and, hence, to appositional mineralization of dentin. PMID:10872993

Ohma, N; Takagi, Y; Takano, Y

2000-06-01

283

The Coordinated Control of a Central Air Conditioning System Based on Variable Chilled Water Temperature and Variable Chilled Water Flow  

E-print Network

At present, regulation of water flow by means of pump frequency conversion is one of the major methods for power-saving in central air conditioning systems. In this article, optimization regulation for central air conditioning system on the basis...

Liu, J.; Mai, Y.; Liu, X.

2006-01-01

284

A new species of Centropages (Copepoda: Calanoida: Centropagidae) from the central Red Sea based on morphological and molecular evidence.  

PubMed

Centropages mohamedi sp. nov. (Copepoda: Calanoida) is described from specimens collected in zooplankton samples off Obhur Creek on the Saudi Arabian coast of the central Red Sea. The new species is most closely related to C. orsinii Giesbrecht, 1889, a species described from the Red Sea and widely distributed in the neritic waters of the Indo-West Pacific region. The new species is mainly distinguished by the female genital double somite, male antennules, male leg 4, and leg 5 of both sexes. DNA sequences of the mitochondrial cytochrome C oxidase subunit one (mtCOI) of the two species differ by 20.8%, supporting their morphology-based identification as distinct species.  PMID:25661620

El-Sherbiny, Mohsen M; Al-Aidaroos, Ali M

2015-01-01

285

Healthcare information exchange system based on a Hybrid central/federated model.  

PubMed

The quality of care can be significantly enhanced and healthcare cost can be substantially reduced if healthcare providers can have access to patient records that are scattered among several paper and electronic based systems. Major challenges of Healthcare Information Exchange result from patient's medical records being kept in several healthcare provider offices, clinics and hospitals in different formats. There are two major problems with healthcare information retrieval. The first problem is lack of visibility and knowledge as to where patient's medical records reside. The second problem is lack of access to information and also incompatibility of data formats. A considerable coverage of Electronic Information Exchange among Electronic Health Record (EHR) systems remains to be implemented despite extensive standardization efforts toward providing solutions. The adoption pace of available standards and solutions has been slow with the exception of some public/government entities. This paper describes a comprehensive and practical solution based on a distributed system with independent subsystems that control and manage processes and data flow of information exchange. The Registrar Subsystem creates a directory of healthcare providers and patients. The Security Subsystem provides authentication and authorization services across all subsystems. The Locators address patient and medical location lookup. The Agents act on behalf of healthcare providers to communicate with other subsystems. The Mediators facilitate information retrieval. The Solution comprises of three levels of participation that allows healthcare providers to join the system easily by starting from basic semi-manual information exchange level and then migrating to a fully electronic and automated information exchange. The Solution is modeled based on variety of standards and protocols used in Internet and other application fields as well as healthcare specific standards and proposals. PMID:25570220

Ghane, Kamran

2014-08-01

286

Rapid decrease of malaria morbidity following the introduction of community-based monitoring in a rural area of central Vietnam  

PubMed Central

Background Despite a successful control programme, malaria has not completely disappeared in Vietnam; it remains endemic in remote areas of central Vietnam, where standard control activities seem to be less effective. The evolution of malaria prevalence and incidence over two and half years in a rural area of central Vietnam, after the introduction of community-based monitoring of malaria cases, is presented. Methods After a complete census, six cross-sectional surveys and passive detection of malaria cases (by village and commune health workers using rapid diagnostic tests) were carried out between March 2004 and December 2006 in Ninh-Thuan province, in a population of about 10,000 individuals. The prevalence of malaria infection and the incidence of clinical cases were estimated. Results Malaria prevalence significantly decreased from 13.6% (281/2,068) in December 2004 to 4.0% (80/2,019) in December 2006. Plasmodium falciparum and Plasmodium vivax were the most common infections with few Plasmodium malariae mono-infections and some mixed infections. During the study period, malaria incidence decreased by more than 50%, from 25.7/1,000 population at risk in the second half of 2004 to 12.3/1,000 in the second half of 2006. The incidence showed seasonal variations, with a yearly peak between June and December, except in 2006 when the peak observed in the previous years did not occur. Conclusion Over a 2.5-year follow-up period, malaria prevalence and incidence decreased by more than 70% and 50%, respectively. Possibly, this could be attributed to the setting up of a passive case detection system based on village health workers, indicating that a major impact on the malaria burden can be obtained whenever prompt diagnosis and adequate treatment are available. PMID:19123932

Thang, Ngo Duc; Erhart, Annette; Hung, Le Xuan; Thuan , Le Khanh; Xa, Nguyen Xuan; Thanh, Nguyen Ngoc; Ky, Pham Van; Coosemans, Marc; Speybroeck, Nico; D'Alessandro, Umberto

2009-01-01

287

Object based change detection of Central Asian Tugai vegetation with very high spatial resolution satellite imagery  

NASA Astrophysics Data System (ADS)

Ecological restoration of degraded riparian Tugai forests in north-western China is a key driver to combat desertification in this region. Recent restoration efforts attempt to recover the forest along with its most dominant tree species, Populus euphratica. The present research observed the response of natural vegetation using an object based change detection method on QuickBird (2005) and WorldView2 (2011) data. We applied the region growing approach to derived Normalized Difference Vegetation Index (NDVI) values in order to identify single P. euphratica trees, delineate tree crown areas and quantify crown diameter changes. Results were compared to 59 reference trees. The findings confirmed a positive tree crown growth and suggest a crown diameter increase of 1.14 m, on average. On a single tree basis, tree crown diameters of larger crowns were generally underestimated. Small crowns were slightly underestimated in QuickBird and overestimated in Worldview2 images. The results of the automated tree crown delineation show a moderate relation to field reference data with R20052: 0.36 and R20112: 0.48. The object based image analysis (OBIA) method proved to be applicable in sparse riparian Tugai forests and showed great suitability to evaluate ecological restoration efforts in an endangered ecosystem.

Gärtner, Philipp; Förster, Michael; Kurban, Alishir; Kleinschmit, Birgit

2014-09-01

288

Tissue profiling of the mammalian central nervous system using human antibody-based proteomics.  

PubMed

A need exists for mapping the protein profiles in the human brain both during normal and disease conditions. Here we studied 800 antibodies generated toward human proteins as part of a Human Protein Atlas program and investigated their suitability for detailed analysis of various levels of a rat brain using immuno-based methods. In this way, the parallel, rather limited analysis of the human brain, restricted to four brain areas (cerebellum, cerebral cortex, hippocampus, and lateral subventricular zone), could be extended in the rat model to 25 selected areas of the brain. Approximately 100 antibodies (12%) revealed a distinct staining pattern and passed validation of specificity using Western blot analysis. These antibodies were applied to coronal sections of the rat brain at 0.7-mm intervals covering the entire brain. We have now produced detailed protein distribution profiles for these antibodies and acquired over 640 images that form the basis of a publicly available portal of an antibody-based Rodent Brain Protein Atlas database (www.proteinatlas.org/rodentbrain). Because of the systematic selection of target genes, the majority of antibodies included in this database are generated against proteins that have not been studied in the brain before. Furthermore optimized tissue processing and colchicine treatment allow a high quality, more extended annotation and detailed analysis of subcellular distributions and protein dynamics. PMID:19351664

Mulder, Jan; Björling, Erik; Jonasson, Kalle; Wernérus, Henrik; Hober, Sophia; Hökfelt, Tomas; Uhlén, Mathias

2009-07-01

289

Wetlands Maps of Central Canada based on L-band SAR Imagery  

NASA Astrophysics Data System (ADS)

Many boreal wetlands appear to be evolving into significant sources of greenhouse gases. The ability to accurately quantify the locations, types, and extents of northern wetlands is important to understanding their role in the global carbon cycle and responses to changes in climate. However, due to the extent of boreal wetlands and their inaccessibility, there have been few maps produced of this important ecosystem. To address this need, we have been constructing high-resolution (100 m) thematic maps of North American boreal wetlands. The maps are developed using space-based synthetic aperture radar (SAR), which is capable of efficiently providing high-resolution imagery of vast and often inaccessible regions. Unlike optical imagery, space-based SAR imagery is unaffected by cloud cover. Additionally, L-band SAR is able to sense vegetation structure and moisture content, as well as ground and surface water characteristics (even under vegetation canopies), thereby providing information unobtainable from optical sensors. Space-based L-band SAR thus constitutes an excellent tool for mapping boreal wetlands. One wetlands map is based on HH-polarized L-band SAR imagery from the Japanese Earth Resources Satellite (JERS-1), collected for both summer and winter in the late 1990s. A second map is based on dual-polarized (HH and HV) imagery from the Phased Array L-band SAR (PALSAR) sensor, collected in the summer of 2007. Prior to classification, a sequence of preprocessing steps are executed, including filtering, mosaicking, resampling, reprojection, co-registration, and the formation of supplementary data layers such as image texture, topographic slope, and proximity to water. This preprocessing is implemented by a semi-automated software suite specifically designed to handle the large volumes of data involved in the project. Training/testing data needed in the classification process are formed by merging national wetland inventory and land cover databases. Finally, a 'Random Forests' decision tree classifier takes in the processed SAR and other data layers, along with the training/testing data, and uses them to produce a thematic wetlands map. The accuracy of the resulting classification product is quantified by calculating producer and user error statistics for all validation pixels within the mapped region. Thematic change maps are generated from the SAR-derived maps, thereby allowing decadal changes in wetland extent and type to be identified. These change maps provide information on wetland dynamics and responses to anthropogenic and climatic influences over a large spatial area. This work was done in part within the ALOS Kyoto & Carbon Initiative, with portions carried out at the University of Southern California and at the Jet Propulsion Laboratory under contract to National Aeronautics and Space Administration. PALSAR data were provided by JAXA/EORC and the Alaska Satellite Facility.

Whitcomb, J.; Moghaddam, M.; Clewley, D.; McDonald, K. C.; Podest, E.; Chapman, B. D.

2013-12-01

290

High-resolution BAC-based map of the central portion of mouse chromosome 5.  

PubMed

The current strategy for sequencing the mouse genome involves the combination of a whole-genome shotgun approach with clone-based sequencing. High-resolution physical maps will provide a foundation for assembling contiguous segments of sequence. We have established a bacterial artificial chromosome (BAC)-based map of a 5-Mb region on mouse Chromosome 5, encompassing three gene families: receptor tyrosine kinases (PdgfraKit-Kdr), nonreceptor protein-tyrosine type kinases (Tec-Txk), and type-A receptors for the neurotransmitter GABA (Gabra2, Gabrb1, Gabrg1, and Gabra4). The construction of a BAC contig was initiated by hybridization screening the C57BL/6J (RPCI-23) BAC library, using known genes and sequence tagged sites (STSs). Additional overlapping clones were identified by searching the database of available restriction fingerprints for the RPCI-23 and RPCI-24 libraries. This effort resulted in the selection of >600 BAC clones, 251 kb of BAC-end sequences, and the placement of 40 known and/or predicted genes within this 5-Mb region. We use this high-resolution map to illustrate the integration of the BAC fingerprint map with a radiation-hybrid map via assembled expressed sequence tags (ESTs). From annotation of three representative BAC clones we demonstrate that up to 98% of the draft sequence for each contig could be ordered and oriented using known genes, BAC ends, consensus sequences for transcript assemblies, and comparisons with orthologous human sequence. For functional studies, annotation of sequence fragments as they are assembled into 50-200-kb stretches will be remarkably valuable. PMID:11591652

Crabtree, J; Wiltshire, T; Brunk, B; Zhao, S; Schug, J; Stoeckert, C J; Bucan, M

2001-10-01

291

Centrality Indices  

Microsoft Academic Search

\\u000a Centrality indices are to quantify an intuitive feeling that in most networks some vertices or edges are more central than\\u000a others. Many vertex centrality indices were introduced for the first time in the 1950s: e.g., the Bavelas index [50, 51],\\u000a degree centrality [483] or a first feedback centrality, introduced by Seeley [510]. These early centralities raised a rush\\u000a of research

Dirk Koschützki; Katharina Anna Lehmann; Leon Peeters; Stefan Richter; Dagmar Tenfelde-podehl; Oliver Zlotowski

2004-01-01

292

Axioms for Centrality  

E-print Network

Given a social network, which of its nodes are more central? This question has been asked many times in sociology, psychology and computer science, and a whole plethora of centrality measures (a.k.a. centrality indices, or rankings) were proposed to account for the importance of the nodes of a network. In this paper, we try to provide a mathematically sound survey of the most important classic centrality measures known from the literature and propose an axiomatic approach to establish whether they are actually doing what they have been designed for. Our axioms suggest some simple, basic properties that a centrality measure should exhibit. Surprisingly, only a new simple measure based on distances, harmonic centrality, turns out to satisfy all axioms; essentially, harmonic centrality is a correction to Bavelas's classic closeness centrality designed to take unreachable nodes into account in a natural way. As a sanity check, we examine in turn each measure under the lens of information retrieval, leveraging sta...

Boldi, Paolo

2013-01-01

293

Treatment of a molasses based distillery effluent in a constructed wetland in central India.  

PubMed

A field-scale 4-celled, horizontal subsurface constructed wetland (CW) was installed to evaluate removal efficiencies of wastewater constituents in an industrial distillery effluent. Total and dissolved solids, NH4-N, TKN, P and COD were measured. This CW design provides four serial cells with synthetic liners and a river gravel base. The first two unplanted cells provide preliminary treatment. Specific gravel depths and ensuing biofilm growth provides anaerobic treatment in Cell 1 and anaerobic treatment in Cell 2. Cell 3 was planted with Typha latifolia with an inserted layer of brick rubble (for phosphorus removal). Locally grown reed, Phragmites karka was planted in Cell 4. COD was reduced from 8420 mg/l 3000 from Cell 1 to the outlet of Cell 4. Likewise other parameters: total and dissolved solids, ammonium and total nitrogen, and total P, indicated declining trends at the 4-celled CW effluent. This study reveals how high strength distillery wastewater strongly impacts morphology, aeration anatomy in the chiseled plant tissues, reed growth; and composition of the biofilm in the specialized substratum. The reliability of a CW for organic and nutrients reduction, in association with a poorly performing conventional system is discussed. There is an immense potential for appropriately designed constructed wetlands to improve high strength wastewaters in India. PMID:11804132

Billore, S K; Singh, N; Ram, H K; Sharma, J K; Singh, V P; Nelson, R M; Dass, P

2001-01-01

294

Late Quaternary Vegetation and Climate Changes in Central Texas Based on the Isotopic Composition of Organic Carbon  

NASA Astrophysics Data System (ADS)

Stable carbon isotope analysis of organic carbon in alluvial deposits and soils of three streams in central Texas reveals significant shifts in the ratio of C 3 to C 4 plant biomass production during the past 15,000 yr. These temporal changes in vegetation appear to be in response to changes in climate. During the late Pleistocene, C 4 plants comprised only about 45 to 50% of the vegetative biomass in this area, suggesting that conditions were cooler and wetter than at any time during the past 15,000 yr. The time between 11,000 and 8000 yr B.P. is interpreted as transitional between late Pleistocene conditions and warmer and drier Holocene conditions based on a slight increase in the abundance of C 4 plant biomass. During the middle Holocene, between approximately 6000 and 5000 yr B.P., mixed C 3/C 4 plant communities were replaced almost completely by C 4-dominated communities, indicating prairie expansion and warmer and drier climatic conditions. By 4000 yr B.P., the abundance of C 4 plant biomass decreased to levels similar to the early Holocene transitional period, suggesting a return to cooler and wetter climatic conditions. No significant shift in the ratio of C 3 to C 4 productivity has occurred during the last 4000 yr, except for a slight increase in the abundance of C 4 plant biomass around 2000 yr B.P. The results of this investigation correlate well with other regional late Quaternary climatic interpretations for central and north Texas, the Southern Plains region, and with other portions of the Great Plains.

Nordt, Lee C.; Boutton, Thomas W.; Hallmark, Charles T.; Waters, Michael R.

1994-01-01

295

A comparative analysis between site-based and centralized ratings and patient self-ratings in a clinical trial of Major Depressive Disorder.  

PubMed

We compared scores from three different ratings methods in a clinical trial of patients with Major Depressive Disorder (MDD). The Quick Inventory of Depressive Symptoms (QIDS-SR16) was compared to site-based clinician and centralized (site-independent) ratings of the Inventory of Depressive Symptoms (IDSc30). An extracted QIDSc16 was used for a matched comparison with the QIDS-SR16. Patient self-ratings were more depressed at baseline than either site-based ratings (p = 0.131) or centralized ratings (p = 0.005), but significantly less depressed at the end of double-blind treatment than either site-based (p = 0.006) or centralized ratings (p = 0.014), and after 12 weeks (site-based ratings: p = 0.048; centralized ratings: p = 0.004). The matched comparisons with patient self-ratings revealed ICC of r = 0.55 (site-based raters) and r = 0.49 (centralized raters) at baseline. After baseline, the correlations between the two different clinician ratings and patient self-ratings improved to r-values between 0.78 and 0.89. At the end of double-blind treatment, site-based raters separated the combination treatment from placebo on the IDSc30 (p = 0.030) whereas neither centralized ratings nor patient self-ratings achieved statistical significance. Alternatively, patient self-ratings separated the combination treatment from buspirone (p = 0.030) whereas neither clinician rating method achieved significance. A "dual" scoring concordance range reduced the placebo response rate and increased the drug effect between the combination treatment and placebo. These findings reveal scoring variability between each of the three ratings methods and challenge the reliability of any single method to accurately assess symptom severity scores, particularly at baseline. The use of "dual" scoring criteria may help to confirm symptom severity scores and improve ratings precision, particularly prior to enrolling subjects into CNS trials. PMID:23562150

Targum, Steven D; Wedel, Pamela C; Robinson, Jill; Daniel, David G; Busner, Joan; Bleicher, Leo S; Rauh, Philip; Barlow, Carrolee

2013-07-01

296

Impurity of Stem Cell Graft by Murine Embryonic Fibroblasts – Implications for Cell-Based Therapy of the Central Nervous System  

PubMed Central

Stem cells have been demonstrated to possess a therapeutic potential in experimental models of various central nervous system disorders, including stroke. The types of implanted cells appear to play a crucial role. Previously, groups of the stem cell network NRW implemented a feeder-based cell line within the scope of their projects, examining the implantation of stem cells after ischemic stroke and traumatic brain injury. Retrospective evaluation indicated the presence of spindle-shaped cells in several grafts implanted in injured animals, which indicated potential contamination by co-cultured feeder cells (murine embryonic fibroblasts – MEFs). Because feeder-based cell lines have been previously exposed to a justified criticism with regard to contamination by animal glycans, we aimed to evaluate the effects of stem cell/MEF co-transplantation. MEFs accounted for 5.3?±?2.8% of all cells in the primary FACS-evaluated co-culture. Depending on the culture conditions and subsequent purification procedure, the MEF-fraction ranged from 0.9 to 9.9% of the cell suspensions in vitro. MEF survival and related formation of extracellular substances in vivo were observed after implantation into the uninjured rat brain. Impurity of the stem cell graft by MEFs interferes with translational strategies, which represents a threat to the potential recipient and may affect the graft microenvironment. The implications of these findings are critically discussed. PMID:25249934

Molcanyi, Marek; Mehrjardi, Narges Zare; Schäfer, Ute; Haj-Yasein, Nadia Nabil; Brockmann, Michael; Penner, Marina; Riess, Peter; Reinshagen, Clemens; Rieger, Bernhard; Hannes, Tobias; Hescheler, Jürgen; Bosche, Bert

2014-01-01

297

Nanoparticle-based drug delivery to improve the efficacy of antiretroviral therapy in the central nervous system  

PubMed Central

Antiretroviral drug therapy plays a cornerstone role in the treatment of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome patients. Despite obvious advances over the past 3 decades, new approaches toward improved management of infected individuals are still required. Drug distribution to the central nervous system (CNS) is required in order to limit and control viral infection, but the presence of natural barrier structures, in particular the blood–brain barrier, strongly limits the perfusion of anti-HIV compounds into this anatomical site. Nanotechnology-based approaches may help providing solutions for antiretroviral drug delivery to the CNS by potentially prolonging systemic drug circulation, increasing the crossing and reducing the efflux of active compounds at the blood–brain barrier, and providing cell/tissue-targeting and intracellular drug delivery. After an initial overview on the basic features of HIV infection of the CNS and barriers to active compound delivery to this anatomical site, this review focuses on recent strategies based on antiretroviral drug-loaded solid nanoparticles and drug nanosuspensions for the potential management of HIV infection of the CNS. PMID:24741312

Gomes, Maria João; Neves, José das; Sarmento, Bruno

2014-01-01

298

A Central Support System Can Facilitate Implementation and Sustainability of a Classroom-Based Undergraduate Research Experience (CURE) in Genomics  

PubMed Central

In their 2012 report, the President's Council of Advisors on Science and Technology advocated “replacing standard science laboratory courses with discovery-based research courses”—a challenging proposition that presents practical and pedagogical difficulties. In this paper, we describe our collective experiences working with the Genomics Education Partnership, a nationwide faculty consortium that aims to provide undergraduates with a research experience in genomics through a scheduled course (a classroom-based undergraduate research experience, or CURE). We examine the common barriers encountered in implementing a CURE, program elements of most value to faculty, ways in which a shared core support system can help, and the incentives for and rewards of establishing a CURE on our diverse campuses. While some of the barriers and rewards are specific to a research project utilizing a genomics approach, other lessons learned should be broadly applicable. We find that a central system that supports a shared investigation can mitigate some shortfalls in campus infrastructure (such as time for new curriculum development, availability of IT services) and provides collegial support for change. Our findings should be useful for designing similar supportive programs to facilitate change in the way we teach science for undergraduates. PMID:25452493

Lopatto, David; Hauser, Charles; Jones, Christopher J.; Paetkau, Don; Chandrasekaran, Vidya; Dunbar, David; MacKinnon, Christy; Stamm, Joyce; Alvarez, Consuelo; Barnard, Daron; Bedard, James E. J.; Bednarski, April E.; Bhalla, Satish; Braverman, John M.; Burg, Martin; Chung, Hui-Min; DeJong, Randall J.; DiAngelo, Justin R.; Du, Chunguang; Eckdahl, Todd T.; Emerson, Julia; Frary, Amy; Frohlich, Donald; Goodman, Anya L.; Gosser, Yuying; Govind, Shubha; Haberman, Adam; Hark, Amy T.; Hoogewerf, Arlene; Johnson, Diana; Kadlec, Lisa; Kaehler, Marian; Key, S. Catherine Silver; Kokan, Nighat P.; Kopp, Olga R.; Kuleck, Gary A.; Lopilato, Jane; Martinez-Cruzado, Juan C.; McNeil, Gerard; Mel, Stephanie; Nagengast, Alexis; Overvoorde, Paul J.; Parrish, Susan; Preuss, Mary L.; Reed, Laura D.; Regisford, E. Gloria; Revie, Dennis; Robic, Srebrenka; Roecklien-Canfield, Jennifer A.; Rosenwald, Anne G.; Rubin, Michael R.; Saville, Kenneth; Schroeder, Stephanie; Sharif, Karim A.; Shaw, Mary; Skuse, Gary; Smith, Christopher D.; Smith, Mary; Smith, Sheryl T.; Spana, Eric P.; Spratt, Mary; Sreenivasan, Aparna; Thompson, Jeffrey S.; Wawersik, Matthew; Wolyniak, Michael J.; Youngblom, James; Zhou, Leming; Buhler, Jeremy; Mardis, Elaine; Leung, Wilson; Threlfall, Jennifer; Elgin, Sarah C. R.

2014-01-01

299

Aetiologies of Central Nervous System infections in adults in Kathmandu, Nepal: A prospective hospital-based study  

PubMed Central

We conducted a prospective hospital based study from February 2009-April 2011 to identify the possible pathogens of central nervous system (CNS) infections in adults admitted to a tertiary referral hospital (Patan Hospital) in Kathmandu, Nepal. The pathogens of CNS infections were confirmed in cerebrospinal fluid (CSF) using molecular diagnostics, culture (bacteria) and serology. 87 patients were recruited for the study and the etiological diagnosis was established in 38% (n = 33). The bacterial pathogens identified were Neisseria meningitidis (n = 6); Streptococcus pneumoniae (n = 5) and Staphylococcus aureus (n = 2) in 13/87(14%). Enteroviruses were found in 12/87 (13%); Herpes Simplex virus (HSV) in 2/87(2%). IgM against Japanese encephalitis virus (JEV) was detected in the CSF of 11/73 (15%) tested samples. This is the first prospective molecular and serology based CSF analysis in adults with CNS infections in Kathmandu, Nepal. JEV and enteroviruses were the most commonly detected pathogens in this setting. PMID:23924886

Giri, Abhishek; Arjyal, Amit; Koirala, Samir; Karkey, Abhilasha; Dongol, Sabina; Thapa, Sudeep Dhoj; Shilpakar, Olita; Shrestha, Rishav; van Tan, Le; Thi Thuy Chinh, Bkrong Nguyen; Krishna K. C., Radheshyam; Pathak, Kamal Raj; Shakya, Mila; Farrar, Jeremy; Van Doorn, H. Rogier; Basnyat, Buddha

2013-01-01

300

A central support system can facilitate implementation and sustainability of a Classroom-based Undergraduate Research Experience (CURE) in Genomics.  

PubMed

In their 2012 report, the President's Council of Advisors on Science and Technology advocated "replacing standard science laboratory courses with discovery-based research courses"-a challenging proposition that presents practical and pedagogical difficulties. In this paper, we describe our collective experiences working with the Genomics Education Partnership, a nationwide faculty consortium that aims to provide undergraduates with a research experience in genomics through a scheduled course (a classroom-based undergraduate research experience, or CURE). We examine the common barriers encountered in implementing a CURE, program elements of most value to faculty, ways in which a shared core support system can help, and the incentives for and rewards of establishing a CURE on our diverse campuses. While some of the barriers and rewards are specific to a research project utilizing a genomics approach, other lessons learned should be broadly applicable. We find that a central system that supports a shared investigation can mitigate some shortfalls in campus infrastructure (such as time for new curriculum development, availability of IT services) and provides collegial support for change. Our findings should be useful for designing similar supportive programs to facilitate change in the way we teach science for undergraduates. PMID:25452493

Lopatto, David; Hauser, Charles; Jones, Christopher J; Paetkau, Don; Chandrasekaran, Vidya; Dunbar, David; MacKinnon, Christy; Stamm, Joyce; Alvarez, Consuelo; Barnard, Daron; Bedard, James E J; Bednarski, April E; Bhalla, Satish; Braverman, John M; Burg, Martin; Chung, Hui-Min; DeJong, Randall J; DiAngelo, Justin R; Du, Chunguang; Eckdahl, Todd T; Emerson, Julia; Frary, Amy; Frohlich, Donald; Goodman, Anya L; Gosser, Yuying; Govind, Shubha; Haberman, Adam; Hark, Amy T; Hoogewerf, Arlene; Johnson, Diana; Kadlec, Lisa; Kaehler, Marian; Key, S Catherine Silver; Kokan, Nighat P; Kopp, Olga R; Kuleck, Gary A; Lopilato, Jane; Martinez-Cruzado, Juan C; McNeil, Gerard; Mel, Stephanie; Nagengast, Alexis; Overvoorde, Paul J; Parrish, Susan; Preuss, Mary L; Reed, Laura D; Regisford, E Gloria; Revie, Dennis; Robic, Srebrenka; Roecklien-Canfield, Jennifer A; Rosenwald, Anne G; Rubin, Michael R; Saville, Kenneth; Schroeder, Stephanie; Sharif, Karim A; Shaw, Mary; Skuse, Gary; Smith, Christopher D; Smith, Mary; Smith, Sheryl T; Spana, Eric P; Spratt, Mary; Sreenivasan, Aparna; Thompson, Jeffrey S; Wawersik, Matthew; Wolyniak, Michael J; Youngblom, James; Zhou, Leming; Buhler, Jeremy; Mardis, Elaine; Leung, Wilson; Shaffer, Christopher D; Threlfall, Jennifer; Elgin, Sarah C R

2014-01-01

301

Nanoparticle-based drug delivery to improve the efficacy of antiretroviral therapy in the central nervous system.  

PubMed

Antiretroviral drug therapy plays a cornerstone role in the treatment of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome patients. Despite obvious advances over the past 3 decades, new approaches toward improved management of infected individuals are still required. Drug distribution to the central nervous system (CNS) is required in order to limit and control viral infection, but the presence of natural barrier structures, in particular the blood-brain barrier, strongly limits the perfusion of anti-HIV compounds into this anatomical site. Nanotechnology-based approaches may help providing solutions for antiretroviral drug delivery to the CNS by potentially prolonging systemic drug circulation, increasing the crossing and reducing the efflux of active compounds at the blood-brain barrier, and providing cell/tissue-targeting and intracellular drug delivery. After an initial overview on the basic features of HIV infection of the CNS and barriers to active compound delivery to this anatomical site, this review focuses on recent strategies based on antiretroviral drug-loaded solid nanoparticles and drug nanosuspensions for the potential management of HIV infection of the CNS. PMID:24741312

Gomes, Maria João; Neves, José das; Sarmento, Bruno

2014-01-01

302

Late Quaternary ostracode-based paleoenvironmental reconstructions from Lake Petén Itzá, Guatemala and Lake Chalco, central Mexico  

NASA Astrophysics Data System (ADS)

Modern and fossil ostracodes in lakes from central Mexico (Chalco) to lowland Guatemala (Petén Itzá) were used to infer paleoenvironmental conditions during the last 45 ka. Ostracode-based paleoenvironmental reconstruction from sediment cores in Lake Petén Itzá was based on a modern calibration data set from 63 water bodies in Guatemala, Mexico (Yucatán Peninsula) which provided information on the modern ecological preferences of 29 ostracode species. Statistical analysis indicated that lake water conductivity and chemical composition determine ostracode distributions on the Yucatán Peninsula and that lake level is a strong determinant of species distribution in Lake Petén Itzá. Transfer functions were applied to fossil species assemblages in long sediment cores from Lake Petén Itzá to infer past conductivity and lake level. Over the past 45 ka, ostracodes in Lake Petén Itzá were sensitive to fluctuations in lake water chemical composition and lake stage. Relative abundances of ostracode taxa and stable isotope values in their shells indicate large environmental changes from the LGM to deglaciation, and into the Holocene. The LGM was characterized by low species richness (n=4), dominance of benthic taxa, cold conditions and moderate to high lake levels. The deglaciation displayed higher species richness (n=6), dominance of nektobenthic taxa, and alternating dry and wet conditions, with low to relatively high lake levels. The Holocene was dominated by the deep-water ostracode Physocypria globula, indicating warmer temperatures and higher lake levels. Preliminary results from Lake Chalco sediment cores indicate ostracodes were scarce during the LGM and deglacial, but displayed higher abundances in older deposits. Ostracodes identified in the sediment record include Limnocythere sp., Candona patzcuaro and Darwinula stevensoni. The only species in common with the Lake Petén Itzá record is D. stevensoni. Deglacial species richness in Chalco (n=3) was lower than in Lake Petén Itzá (n=6). Because the species in Lake Chalco cores differ from those in the Petén Itzá record, a training set specifically for central Mexico was developed, using 28 water bodies. About 15 ostracode species have been identified and transfer functions to infer environmental variables will be developed. We will compare stable oxygen and carbon isotope records, measured on fossil ostracode remains in dated cores from Lakes Chalco and Petén Itzá, to infer past regional climate conditions.

Perez, L.; Lozano, S.; Caballero, M.; Brenner, M.; Schwalb, A.

2013-05-01

303

Effects of unpolymerized resin components on the function of accessory cells derived from the rat incisor pulp.  

PubMed

Monomeric resin components from dental composites are toxic to fibroblasts in culture and thus may interfere with the local immune system of the pulp, reducing its effective defense potential, either by cytotoxicity or by a more specific immune mechanism. Therefore, the present study was undertaken to observe the cytotoxic effects elicited by certain unpolymerized components of resin composites upon the function of accessory pulp cells in mitogen-induced proliferation of T-lymphocytes. Accessory cells from the rat incisor pulp were released following enzymatic digestion with collagenase. The assay included incubation of these cells with purified T-lymphocytes from cervical lymph nodes for 72 h in the presence of different concentrations of the resin components. The proliferative T-lymphocyte response was monitored by 3H-thymidine incorporation. Initially, we conducted experiments on spleen cells to determine the proper concentration intervals for suitable testing of the resin components. To assess the individual susceptibility of accessory cells and T-lymphocytes, we pre-treated each of these cells with some of the test materials prior to assay. At low concentrations, urethane dimethacrylate (UDMA), bisglycidyl methacrylate (bis-GMA), triethylene glycol dimethacrylate (TEGDMA), and bis-phenol A (BPA) increased spleen cell proliferation to concanavalin A (con A). Purified T-lymphocytes stimulated by pulpal cells did not show enhanced responses to UDMA, bis-GMA, glycidyl mehtacrylate (GMA), or N,N,-dihydroxyethyl-p-toluidine (DHEpT). At higher concentrations, all substances except camphoroquinone (CAMP) showed inhibitory effects in both test systems. The in vitro study shows that resin components can evoke either immunosuppression or immunostimulation on mitogen-driven proliferation of purified T-lyumphocytes and spleen cells. PMID:7790593

Jontell, M; Hanks, C T; Bratel, J; Bergenholtz, G

1995-05-01

304

Ca-binding domains in the odontoblast layer of rat molars and incisors under normal and pathological conditions.  

PubMed

We recently reported the presence of high concentrations of a Ca-binding matrix in the circumpulpal dentin of rat incisors which had been prevented from mineralization by a systemic administration of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP), a type of bisphosphonates, thus suggesting the role of the putative Ca-binding matrix in the appositional mineralization of circumpulpal dentin (TAKANO et al., 1998, 2000; OHMA et al., 2000). In this study, we examined the distribution of Ca-binding domains in the pulp tissue of normal rat teeth and its changes under the influence of HEBP, in order to identify and clarify the role of the Ca-binding matrix in the physiological process of dentin mineralization. Observation of the normal rat tooth pulp showed occasional, tiny extracellular deposits of Ca-enriched material in the odontoblast layer, associated primarily with pericapillary regions. Such deposits were immunopositive for dentin sialoprotein (DSP), displayed high levels of X-ray peaks for calcium and phosphorus, and showed a drastic increase in amount by daily injections of HEBP. A brief vascular perfusion of high Ca-containing solution in normal animals caused the extensive deposition of Ca-P complexes along the basolateral membranes of odontoblasts but not in the other regions of the pulp tissue. These data suggest the existence of DSP-enriched extracellular Ca-binding domains in the odontoblast layer and also indicate a novel Ca-binding property of the basolateral membranes of odontoblasts. Since DSP is primarily synthesized as dentin sialophosphoprotein (DSPP) and later cleaved into dentin phosphophoryn (DPP) and DSP in odontoblasts, and since DSP has no notable affinity for Ca, the sites of DSP-immunopositive Ca-P deposits in the odontoblast layer may also contain DPP, a highly phosphorylated acidic protein having a strong binding property for calcium. Characteristic Ca-binding properties seen in the odontoblast layer appear to be related to the regulation of the appositional mineralization of circumpulpal dentin. PMID:12501891

Watanabe, Eiko; Takano, Yoshiro

2002-10-01

305

1-Hydroxyethylidene-1,1-bisphosphonate (HEBP) simultaneously induces two distinct types of hypomineralization in the rat incisor dentine.  

PubMed

Effects of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) on the dentinogenesis of the rat maxillary incisor were microradiographically examined 96 hours after a single subcutaneous injection. HEBP produced hypomineralized incremental bands in the enamel (HPOe) and in the dentine (outer HPO1 and inner HPO2) in a dose-dependent manner. In the labial dentine, both HPO1 and HPO2 did not extend apically beyond the apical limit of the HPOe and were thus located in the circumpulpal dentine. The two lesions in the labial dentine fully developed with a dosage of 10 mg/ P/kg or larger, and with 15 mg P/kg or larger, gross hypoplastic lesions developed. Therefore, histological analysis at shorter postinjection intervals was carried out on the labial dentine with 10 mg P/kg of HEBP. The HPO1 appeared along the dentine-predentine junction by 24 hours and was characterized by reduced numbers of inorganic crystals and 10 nm particles which invested the collagen fibrils. Therefore, the HPO1 was judged to be produced by the disturbance of transformation of the predentine to dentine. The precursor lesion of HPO2 appeared in the proximal predentine by 4 hours, and was characterized by reduced number of collagen fibrils and unusually coarse interfibrillar stippled material. This lesion migrated to the dentine by 96 hours and became the HPO2, which was characterized by reduced number of collagen fibrils. Individual collagen fibrils in the HPO2 were invested by as many inorganic crystals and 10 nm particles as in the normal dentine. The HPO2 is considered to be produced by the disturbance of organic matrix formation. PMID:2492886

Ogawa, Y; Adachi, Y; Hong, S S; Yagi, T

1989-01-01

306

Central Odontogenic Fibroma of the Gingiva: A Case Report  

PubMed Central

In this paper, we present a case of an uncommon and slow-growing tumor known as a central odontogenic fibroma (COF). The patient in question is a 53-year-old African-American man who was referred for periodontal evaluation of asymptomatic space formation between the mandibular central incisors. Clinical and radiological evaluations disclosed tumor-like tissue expanding the alveolar ridge in the buccolingual dimension, along with thinning of the cortical plates. Surgical excision was performed, and the specimen was sent for histopathology, which later confirmed that the lesion was a COF. Periodontal regenerative therapy was performed to rebuild the hard and soft tissue that had been compromised as a result of tumor expansion. The site was grafted, with excellent results. PMID:25646136

Soolari, Ahmad; Khan, Asghar

2015-01-01

307

Knowledge-based soil inference modeling for estimating soil productivity and grain yield in north-central Missouri  

Technology Transfer Automated Retrieval System (TEKTRAN)

We used ArcSIE (Soil Inference Engine) software to model soils resembling those mapped by NRCS soil survey, for eight 12-digit watersheds in the Central Claypan (MLRA113) in north-central Missouri. Our source data for modeling was the 10m USGS Digital Elevation Model. Environmental Covariates used i...

308

Remodeling of central metabolism in invasive breast cancer compared to normal breast tissue – a GC-TOFMS based metabolomics study  

PubMed Central

Background Changes in energy metabolism of the cells are common to many kinds of tumors and are considered a hallmark of cancer. Gas chromatography followed by time-of-flight mass spectrometry (GC-TOFMS) is a well-suited technique to investigate the small molecules in the central metabolic pathways. However, the metabolic changes between invasive carcinoma and normal breast tissues were not investigated in a large cohort of breast cancer samples so far. Results A cohort of 271 breast cancer and 98 normal tissue samples was investigated using GC-TOFMS-based metabolomics. A total number of 468 metabolite peaks could be detected; out of these 368 (79%) were significantly changed between cancer and normal tissues (p<0.05 in training and validation set). Furthermore, 13 tumor and 7 normal tissue markers were identified that separated cancer from normal tissues with a sensitivity and a specificity of >80%. Two-metabolite classifiers, constructed as ratios of the tumor and normal tissues markers, separated cancer from normal tissues with high sensitivity and specificity. Specifically, the cytidine-5-monophosphate / pentadecanoic acid metabolic ratio was the most significant discriminator between cancer and normal tissues and allowed detection of cancer with a sensitivity of 94.8% and a specificity of 93.9%. Conclusions For the first time, a comprehensive metabolic map of breast cancer was constructed by GC-TOF analysis of a large cohort of breast cancer and normal tissues. Furthermore, our results demonstrate that spectrometry-based approaches have the potential to contribute to the analysis of biopsies or clinical tissue samples complementary to histopathology. PMID:22823888

2012-01-01

309

Scanning electron microscopy of final enamel formation in rat mandibular incisors following single injections of 1-hydroxyethylidene-1,1-bisphosphonate.  

PubMed

A single, high dose of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) results in three different types of lesions along the enamel surface of the rat incisor, one of which is seen as a "bright band" crossing the final enamel surface in the scanning electron microscope (SEM). The present study presents the structural surface features of final enamel formation and its subsequent maturation in normal and HEBP-exposed rats. The position of the bright band is examined in relation to where the Tomes processes pits disappear (DTPP), where the boundary between "light" and "dark" enamel (LDB) as seen by SEM is located, and in particular, where the so-called opaque boundary (OB) is positioned. Groups of rats were given a subcutaneous dose of 0, 5, or 10 mg P/kg body wt of HEBP and killed at intervals of either 12 hours or 2 or 9 days. The mandibular incisors were processed for SEM after enzymatic digestion of enamel organ remains. Enamel surface nodules, 100-300 nm in diameter and composed of smaller units, were evident at the start of final enamel formation which was defined as the area from DTPP to LDB. With increasing maturation, the nodules merged to form a smooth surface. In HEBP-treated animals, growth and merging of these surface nodules became arrested at the time of injection resulting in an irreversible "porous" stage corresponding to that part of the surface enamel. This area--the bright band--developed corresponding to the start of the area of final enamel formation and was subsequently carried incisally during the eruption of the incisor.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8467412

Weile, V; Josephsen, K; Fejerskov, O

1993-04-01

310

The Lilongwe Central Hospital Patient Management Information System: A Success in Computer-Based Order Entry Where One Might Least Expect It  

PubMed Central

Computer-based order entry is a powerful tool for enhancing patient care. A pilot project in the pediatric department of the Lilongwe Central Hospital (LCH) in Malawi, Africa has demonstrated that computer-based order entry (COE): 1) can be successfully deployed and adopted in resource-poor settings, 2) can be built, deployed and sustained at relatively low cost and with local resources, and 3) has a greater potential to improve patient care in developing than in developed countries. PMID:14728338

GP, Douglas; RA, Deula; SE, Connor

2003-01-01

311

Seismicity in Central North Africa at low magnitudes: A first look at the TAM event detected data base  

SciTech Connect

Teleseismic observations of seismicity in the central North Africa region show that the region is aseismic. This is true for earthquakes with a body wave magnitude greater than about 4 or so. For earthquakes with body wave magnitudes substantially below about 4, the teleseismic observations of seismicity in the central Sahara are incomplete since smaller earthquakes would probably not be detected and located by the current teleseismic monitoring networks. Only one known open seismic station has been operating in the central Sahara. This is the Tamanrasset (TAM) seismic station in southern Algeria. A simple analysis of data records from this station can be used to determine if the central Sahara is also relatively aseismic at magnitudes substantially below 4. That is the primary purpose of this study.

Harben, P.E.,

1997-01-01

312

Mapping hydrological environments in central Amazonia: ground validation and surface model based on SRTM DEM data corrected for deforestation  

NASA Astrophysics Data System (ADS)

One of the most important freely available digital elevation models (DEMs) for Amazonia is the one obtained by the Shuttle Radar Topography Mission (SRTM). However, since SRTM tends to represent the vegetation surface instead of the ground surface, the broad use of SRTM DEM as a framework for terrain description in Amazonia is hampered by the presence of deforested areas. We present here two data sets: (1) a deforestation-corrected SRTM DEM for the interfluve between the Purus and Madeira rivers, in central Amazonia, which passed through a careful identification of different environments and has deforestation features corrected by a new method of increasing pixel values of the DEM (Rennó, 2009); and (2) a set of 18 hydrological-topographic descriptors based on the corrected SRTM DEM. Deforestation features are related with the opening of an 800 km road in the central part of the interfluve and occupancy of its vicinity. We used topographic profiles from the pristine forest to the deforested feature to evaluate the recovery of the original canopy coverage by minimizing canopy height variation (corrections ranged from 1 to 38 m). The hydrological-topographic description was obtained by the Height Above the Nearest Drainage (HAND) algorithm, which normalizes the terrain elevation (above sea level) by the elevation of the nearest hydrologically connected drainage. The validation of the HAND data set was done by in situ hydrological description of 110 km of walking trails also available in this data set. The new SRTM DEM expands the applicability of SRTM data for landscape modelling; the data sets of hydrological features based on topographic modelling are undoubtedly appropriate for ecological modelling and an important contribution to environmental mapping of Amazonia. The deforestation-corrected SRTM DEM is available at http://ppbio.inpa.gov.br/knb/metacat/naman.318.3/ppbio; the polygons selected for deforestation correction are available at http://ppbio.inpa.gov.br/knb/metacat/naman.317.3/ppbio; the set of hydrological-topographic descriptors is available at http://ppbio.inpa.gov.br/knb/metacat/naman.544.2/ppbio; the environmental description of access trails is available at http://ppbio.inpa.gov.br/knb/metacat/naman.541.2/ppbio; and the limits of deforestation corrections and drainage validation are available at http://ppbio.inpa.gov.br/knb/metacat/liliandias.38.1/ppbio.

Moulatlet, G. M.; Rennó, C. D.; Costa, F. R. C.; Emilio, T.; Schietti, J.

2015-03-01

313

ScienceCentral: open access full-text archive of scientific journals based on Journal Article Tag Suite regardless of their languages  

PubMed Central

ScienceCentral, a free or open access, full-text archive of scientific journal literature at the Korean Federation of Science and Technology Societies, was under test in September 2013. Since it is a Journal Article Tag Suite-based full text database, extensible markup language files of all languages can be presented, according to Unicode Transformation Format 8-bit encoding. It is comparable to PubMed Central: however, there are two distinct differences. First, its scope comprises all science fields; second, it accepts all language journals. Launching ScienceCentral is the first step for free access or open access academic scientific journals of all languages to leap to the world, including scientific journals from Croatia. PMID:24266292

Huh, Sun

2013-01-01

314

Structure-based functional characterization of Repressor of Toxin (Rot), a central regulator of Staphylococcus aureus virulence  

DOE PAGESBeta

Staphylococcus aureus is responsible for a large number of diverse infections worldwide. In order to support its pathogenic lifestyle, S. aureus has to regulate the expression of virulence factors in a coordinated fashion. One of the central regulators of the S. aureus virulence regulatory networks is the transcription factor repressor of toxin (Rot). Rot plays a key role in regulating S. aureus virulence through activation or repression of promoters that control expression of a large number of critical virulence factors. However, the mechanism by which Rot mediates gene regulation has remained elusive. Here, we have determined the crystal structure of Rot and used this information to probe the contribution made by specific residues to Rot function. Rot was found to form a dimer, with each monomer harboring a winged helix-turn-helix (WHTH) DNA-binding motif. Despite an overall acidic pI, the asymmetric electrostatic charge profile suggests that Rot can orient the WHTH domain to bind DNA. Structure-based site-directed mutagenesis studies demonstrated that R91, at the tip of the wing, plays an important role in DNA binding, likely through interaction with the minor groove. We also found that Y66, predicted to bind within the major groove, contributes to Rot interaction with target promoters. Evaluation of Rot binding to different activated and repressed promoters revealed that certain mutations on Rot exhibit promoter-specific effects, suggesting for the first time that Rot differentially interacts with target promoters. This work provides insight into a precise mechanism by which Rot controls virulence factor regulation in S. aureus.

Killikelly, April [New York Univ. School of Medicine, NY (United States). Dept. of Biochemistry and Molecular Pharmacology; Jakoncic, Jean [Brookhaven National Laboratory (BNL), Upton, NY (United States). Photon Sciences Directorate; Benson, Meredith A. [New York Univ. School of Medicine, NY (United States). Dept. of Microbiology; Ohneck, Elizabeth A. [New York Univ. School of Medicine, NY (United States). Dept. of Microbiology; Sampson, Jared M. [New York Univ. School of Medicine, NY (United States). Dept. of Biochemistry and Molecular Pharmacology; Spurrier, Brett [New York Univ. School of Medicine, NY (United States). Dept. of Biochemistry and Molecular Pharmacology; Torres, Victoer J. [New York Univ. School of Medicine, NY (United States). Dept. of Microbiology; Kong, Xian-Peng [New York Univ. School of Medicine, NY (United States). Dept. of Biochemistry and Molecular Pharmacology

2014-12-04

315

Structure-based functional characterization of repressor of toxin (Rot), a central regulator of Staphylococcus aureus virulence.  

PubMed

Staphylococcus aureus is responsible for a large number of diverse infections worldwide. In order to support its pathogenic lifestyle, S. aureus has to regulate the expression of virulence factors in a coordinated fashion. One of the central regulators of the S. aureus virulence regulatory networks is the transcription factor repressor of toxin (Rot). Rot plays a key role in regulating S. aureus virulence through activation or repression of promoters that control expression of a large number of critical virulence factors. However, the mechanism by which Rot mediates gene regulation has remained elusive. Here, we have determined the crystal structure of Rot and used this information to probe the contribution made by specific residues to Rot function. Rot was found to form a dimer, with each monomer harboring a winged helix-turn-helix (WHTH) DNA-binding motif. Despite an overall acidic pI, the asymmetric electrostatic charge profile suggests that Rot can orient the WHTH domain to bind DNA. Structure-based site-directed mutagenesis studies demonstrated that R(91), at the tip of the wing, plays an important role in DNA binding, likely through interaction with the minor groove. We also found that Y(66), predicted to bind within the major groove, contributes to Rot interaction with target promoters. Evaluation of Rot binding to different activated and repressed promoters revealed that certain mutations on Rot exhibit promoter-specific effects, suggesting for the first time that Rot differentially interacts with target promoters. This work provides insight into a precise mechanism by which Rot controls virulence factor regulation in S. aureus. PMID:25331435

Killikelly, April; Benson, Meredith A; Ohneck, Elizabeth A; Sampson, Jared M; Jakoncic, Jean; Spurrier, Brett; Torres, Victor J; Kong, Xiang-Peng

2015-01-01

316

Structure-based functional characterization of Repressor of Toxin (Rot), a central regulator of Staphylococcus aureus virulence  

SciTech Connect

Staphylococcus aureus is responsible for a large number of diverse infections worldwide. In order to support its pathogenic lifestyle, S. aureus has to regulate the expression of virulence factors in a coordinated fashion. One of the central regulators of the S. aureus virulence regulatory networks is the transcription factor repressor of toxin (Rot). Rot plays a key role in regulating S. aureus virulence through activation or repression of promoters that control expression of a large number of critical virulence factors. However, the mechanism by which Rot mediates gene regulation has remained elusive. Here, we have determined the crystal structure of Rot and used this information to probe the contribution made by specific residues to Rot function. Rot was found to form a dimer, with each monomer harboring a winged helix-turn-helix (WHTH) DNA-binding motif. Despite an overall acidic pI, the asymmetric electrostatic charge profile suggests that Rot can orient the WHTH domain to bind DNA. Structure-based site-directed mutagenesis studies demonstrated that R91, at the tip of the wing, plays an important role in DNA binding, likely through interaction with the minor groove. We also found that Y66, predicted to bind within the major groove, contributes to Rot interaction with target promoters. Evaluation of Rot binding to different activated and repressed promoters revealed that certain mutations on Rot exhibit promoter-specific effects, suggesting for the first time that Rot differentially interacts with target promoters. This work provides insight into a precise mechanism by which Rot controls virulence factor regulation in S. aureus.

Killikelly, April [New York Univ. School of Medicine, NY (United States). Dept. of Biochemistry and Molecular Pharmacology; Jakoncic, Jean [Brookhaven National Laboratory (BNL), Upton, NY (United States). Photon Sciences Directorate; Benson, Meredith A. [New York Univ. School of Medicine, NY (United States). Dept. of Microbiology; Ohneck, Elizabeth A. [New York Univ. School of Medicine, NY (United States). Dept. of Microbiology; Sampson, Jared M. [New York Univ. School of Medicine, NY (United States). Dept. of Biochemistry and Molecular Pharmacology; Spurrier, Brett [New York Univ. School of Medicine, NY (United States). Dept. of Biochemistry and Molecular Pharmacology; Torres, Victoer J. [New York Univ. School of Medicine, NY (United States). Dept. of Microbiology; Kong, Xian-Peng [New York Univ. School of Medicine, NY (United States). Dept. of Biochemistry and Molecular Pharmacology

2014-12-04

317

Prevalence, Pharmacological Treatment, and Control of Cardiometabolic Risk Factors among Older People in Central Stockholm: A Population-Based Study  

PubMed Central

Background Cardiometabolic risk factors and related cardiovascular diseases represent major threats to healthy aging. Objective We aimed to estimate distribution, pharmacological treatment, and control of main cardiometabolic risk factors among older people. Methods This population-based study included 3363 participants (age?60 years, 64.9% women) in the Swedish National study on Aging and Care in Kungsholmen, in central Stockholm, Sweden (2001-2004). Data on demographics, cardiometabolic risk factors (hypertension, obesity, diabetes, and high cholesterol), and medication use were collected through face-to-face interviews, clinical examinations, laboratory tests, and the inpatient register. Cardiometabolic risk factors were defined following the most commonly used criteria. Prevalence was standardized using local census data. Results The age- and sex-standardized prevalence of diabetes, obesity, high cholesterol, and hypertension was 9.5%, 12.8%, 49.7%, and 74.9%, respectively. The prevalence of hypertension and diabetes increased with age, whereas the prevalence of obesity and high cholesterol decreased with age. Forty-nine percent of older adults had two or more cardiometabolic risk factors; 9.8% had three or more. Overall, 55.5% of people with hypertension, 50.3% with diabetes, and 25.0% with high cholesterol received pharmacological treatment. Of those treated pharmacologically, 49.4%, 38.1%, and 85.5% reached therapeutic goals for hypertension (blood pressure<150/90 mmHg), diabetes (glycated haemoglobin<7%), and high cholesterol (total cholesterol<6.22 mmol/l), respectively. Conclusions Hypertension, high cholesterol, and clustering of cardiometabolic risk factors were common among older people in Stockholm, but pharmacological treatment and control of these major factors can be improved. Appropriate management of cardiometabolic profiles among older people may help improve cardiovascular health and achieve healthy aging. PMID:25799502

Wang, Rui; Fratiglioni, Laura; Liang, Yajun; Welmer, Anna-Karin; Xu, Weili; Mangialasche, Francesca; Johnell, Kristina; Qiu, Chengxuan

2015-01-01

318

Field based measurements of albedo for two candidate perennial cellulosic feedstocks and row crops in Central Illinois  

NASA Astrophysics Data System (ADS)

The production of perennial cellulosic feedstocks for bioenergy present the potential to diversify regional economies and the national energy supply, while also serving as a climate 'regulators' due to a number of biogeochemical and biophysical differences relative to row crops. Numerous observationally and modeling based approaches, including life cycle analyses have investigated biogeochemical tradeoffs, such as increased carbon sequestration and biophysical increased water use, associated with growing cellulosic feedstocks. A less understood aspect is the biophysical changes associated with the difference in albedo, which will alter the local energy balance and could cause a local to regional cooling several times larger than that associated with offsetting carbon. To address this factor an experiment consisting of paired fields of Miscanthus and Switchgrass, two of the leading perennial cellulosic feedstock candidates, and traditional row crops was established in central Illinois. Data from the first two growing seasons indicate that this effect is most pronounced during the spring and fall as perennial biofuel crops green up earlier and senesce later than common annual row crops. The albedo of the perennials converges to that of the row crops during the growing season as the canopies develop. During the early winter, before the perennial crops are harvested, the albedo over fallow soybean and maize fields can vary greatly depending on snowfall and, to a lesser extent, soil moisture, whereas perennials show less variation. Thus, perennial biofuel crops also have the potential to buffer the local environment against short-term variations in climate. These factors should be considered when evaluating the tradeoffs and climate-regulation services associated with large-scale planting of bioenergy crops.

Miller, J. N.; VanLoocke, A.; Bernacchi, C. J.

2012-12-01

319

Mutation analysis of BRIP1 in male breast cancer cases: a population-based study in Central Italy.  

PubMed

Breast cancer (BC) in men is rare compared with BC in women, but its incidence is increasing along with attention toward this uncommon disease. Although with some differences, male and female BC share similar genetic predisposition factors, including BRCA1/2, CHEK2, and PALB2 mutations. As other BRCA1/2 functionally related DNA repair genes, such as CHEK2 and PALB2, BRIP1 is considered a moderate-penetrance BC susceptibility gene. At present, the role of BRIP1 on BC susceptibility in men is unknown. In this study, we aimed to assess whether BRIP1 variants may contribute to male BC (MBC) risk, by screening 97 MBC cases, all negative for BRCA1/2, CHEK2, and PALB2 mutations, selected from a population-based series of 126 MBCs from Central Italy. A total of five BRIP1 germ-line sequence alterations, three coding, and two non-coding variants, were detected in our series. The two non-coding variants IVS4-28G > A and 3'UTR 4049C > T were classified as neutral by in silico analysis. Of the three coding variants, one was a silent variant (E879E) and two resulted in amino acid substitution (R264W and P919S) showing a putative pathogenic role by in silico analysis. However, further analysis of tumor-associated loss of heterozygosity and the frequency of variant alleles, tested in 203 male population controls, suggested a neutral effect for both of these variants. Overall, our results indicate that BRIP1 variants may not play a relevant role in MBC predisposition. PMID:21165771

Silvestri, Valentina; Rizzolo, Piera; Falchetti, Mario; Zanna, Ines; Masala, Giovanna; Bianchi, Simonetta; Palli, Domenico; Ottini, Laura

2011-04-01

320

Infection risk factors associated with seropositivity for Toxoplasma gondii in a population-based study in the Central Region, Ghana.  

PubMed

SUMMARY About 20-90% of the world's population has had contact with Toxoplasma gondii parasites. The aim of this study was to determine the seroprevalence and risk factors associated with T. gondii infection in the Central Region, Ghana. A community-based cross-sectional study was conducted in three selected communities. Serum samples were tested for the presence of anti-T. gondii IgG and IgM antibodies by ELISA. A serological criterion for seropositivity was a positive test result for any of the two anti-Toxoplasma IgG or IgM antibodies or a combination of both. In all, 390 participants of mean age 47·0 years consisting of 118 (30·3%) males and 272 (69·7%) females were tested. The overall seroprevalence of T. gondii was 85% (333/390) where fishermen, farmers and fishmongers, respectively, had the highest seropositivity. IgG and IgM antibodies were detected in 329 (84%) and 25 (6%), respectively, while both IgG and IgM antibodies were detected in 21 (5%) of the participants. Respectively, 1% (4/390) and 79% (308/390) of participants tested positive for IgM-only and IgG-only antibodies. There was a significant relationship between Toxoplasma seropositivity and contact with soil, presence of a cat in the surrounding area, age, sources of drinking water, level of formal education, and socioeconomic status. The results suggest that the seashore may serve as a good ground for sporulation and survival of Toxoplasma oocysts. PMID:25373611

Abu, E K; Boampong, J N; Ayi, I; Ghartey-Kwansah, G; Afoakwah, R; Nsiah, P; Blay, E

2014-11-01

321

injections based on a 200,000-year record of Plinian eruptions along the Central American Volcanic Arc  

NASA Astrophysics Data System (ADS)

We present for the first time a self-consistent methodology connecting volcanological field data to global climate model estimates for a regional time series of explosive volcanic events. Using the petrologic method, we estimated SO2 emissions from 36 detected Plinian volcanic eruptions occurring at the Central American Volcanic Arc (CAVA) during the past 200,000 years. Together with simple parametrized relationships collected from past studies, we derive estimates of global maximum volcanic aerosol optical depth (AOD) and radiative forcing (RF) describing the effect of each eruption on radiation reaching the Earth's surface. In parallel, AOD and RF time series for selected CAVA eruptions are simulated with the global aerosol model MAECHAM5-HAM, which shows a relationship between stratospheric SO2 injection and maximum global mean AOD that is linear for smaller volcanic eruptions (<5 Mt SO2) and nonlinear for larger ones (?5 Mt SO2) and is qualitatively and quantitatively consistent with the relationship used in the simple parametrized approximation. Potential climate impacts of the selected CAVA eruptions are estimated using an earth system model of intermediate complexity by RF time series derived by (1) directly from the global aerosol model and (2) from the simple parametrized approximation assuming a 12-month exponential decay of global AOD. We find that while the maximum AOD and RF values are consistent between the two methods, their temporal evolutions are significantly different. As a result, simulated global maximum temperature anomalies and the duration of the temperature response depend on which RF time series is used, varying between 2 and 3 K and 60 and 90 years for the largest eruption of the CAVA dataset. Comparing the recurrence time of eruptions, based on the CAVA dataset, with the duration of climate impacts, based on the model results, we conclude that cumulative impacts due to successive eruptions are unlikely. The methodology and results presented here can be used to calculate approximate volcanic forcings and potential climate impacts from sulfur emissions, sulfate aerosol or AOD data for any eruption that injects sulfur into the tropical stratosphere.

Metzner, D.; Kutterolf, S.; Toohey, M.; Timmreck, C.; Niemeier, U.; Freundt, A.; Krüger, K.

2014-10-01

322

Influence of fatigue testing and cementation mode on the load-bearing capability of bovine incisors restored with crowns and FRC posts.  

PubMed

The aim of the study was to evaluate the influence of fatigue and cementation mode on the fracture behaviour of endodontically treated bovine incisors restored with fiber-reinforced-composite (FRC) posts and crowns. Forty-eight endodontically treated incisors were restored with FRC posts, composite build-ups, and cast crowns. In 16 teeth, each of the posts were cemented conventionally with KetacCem (3M Espe) or adhesively with Panavia F (Kuraray) or RelyXUniCem (3M Espe). One-half of the specimens in each group were subjected to thermal cycling with 10,000 cycles at 5-55°C and mechanical aging, loading the specimens in 1,200,000 cycles with 50 N. Fracture resistance was determined by loading the specimens until fracture at an angle of 45°. The loading test showed that cementation mode and fatigue testing had an influence on the load bearing capability. Before fatigue testing no statistically significant differences between the different cementation modes could be detected. After fatigue testing, conventionally cemented FRC posts lead to statistically significant higher fracture loads compared to adhesively luted posts. Most specimens fractured in a favourable way, independent from the type of cementation. PMID:21282879

Nothdurft, Frank P; Schmitt, Thomas; Rupf, Stefan; Pospiech, Peter R

2011-01-01

323

Demonstration of putative Ca-binding domains in dentin matrix of rat incisors after daily injections of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP).  

PubMed

In order to clarify the initial process of dentin mineralization, the inhibitory effect of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) on dentin mineralization was investigated. Rats (100 g) were subcutaneously injected with HEBP (8 mg P/kg) for 7 or 14 d, and the incisors were processed for Ca histochemistry and/or electron microscopy. HEBP-treated incisors demonstrated ladder-like alternate rows of mineralized and non-mineralized dentin at the apical end. GBHA revealed moderate Ca reactions in the non-mineralized circumpulpal dentin matrix where electron microscopy revealed rich distribution of fine mesh-like electron-dense material. Non-mineralized mantle dentin matrix was negative for Ca but contained numerous matrix vesicles (MVs) filled with crystalline and/or amorphous mineral deposits. Mineralization of circumpulpal dentin occurred independently of MV-rich mantle dentin layer in affected specimens. Our data provide histochemical evidence of possible Ca-binding property of the circumpulpal dentin matrix and its absence in the mantle dentin where MV-mediated mineralization occurs. In the mantle dentin, HEBP does not interfere with crystal growth in MVs but inhibits its outgrowth after membrane rupture. It is proposed that circumpulpal dentin matrix has a potential to mineralize independently of MV-mediated mineralization of mantle dentin, although MVs determine the initial site and timing of dentin mineralization. PMID:9541237

Takano, Y; Sakai, H; Baba, O; Sakamoto, Y; Terashima, T; Ohya, K; Kurosaki, N

1998-01-01

324

Intermittent inhibition of dentin mineralization of rat incisors under continual infusion of 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) using a subcutaneous mini osmotic pump.  

PubMed

The inhibitory effect of the continual administration of 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) (8 mgP/kg/day) through a mini osmotic pump on dentin mineralization was examined in relation to the diurnal rhythm of the rat and compared with that of daily injections of same amounts of HEBP known to inhibit dentin mineralization. After daily injections of HEBP, a series of alternating rows of mineralized and non-mineralized dentin islands appeared in the newly formed portion of the crown-analogue of rat incisors. A similar phenomenon occurred under the continual administration of HEBP in rats raised either under regular environmental photofraction or constant lighting conditions. The average distance between the adjacent mineralized dentin islands was 521.0 +/- 51.3 microns in the injected rats. After continual HEBP administration, this was 426.0 +/- 13.2 microns and 416.5 +/- 19.4 microns under ordinary photofraction and constant light, respectively. Although the pattern of individual mineralized dentin islands tended to become irregular in nocturnal rats, no statistical difference was noted between the two values. Rows of mineralized and non-mineralized dentin islands also appeared in the root analogue dentin. No sign of the intermittent inhibition of mineralization was recognized in mesodermal hard tissues other than dentin in the HEBP-affected animals. These data implicate the presence of intrinsic cycles in dentin mineralization at the growing end of rat incisors independent of environmental photofraction as well as the ameloblast function. PMID:10399541

Sakai, H; Takano, Y; Ohya, K; Kurosaki, N

1999-05-01

325

Effects of single doses of 1-hydroxyethylidene-1,1-bisphosphonate on the mineralizing front of rat incisor enamel: a microradiographic and scanning electron microscopic study.  

PubMed

The effects of a single dose of HEBP were examined by injecting rats subcutaneously with various doses (0.5, 1, 2.5, 5 and 10 mg P/kg body wt) and killing them either 2 or 9 days after injection. The maxillary incisors were processed for microradiography and the mandibular incisors for scanning electron microscopy after enzymatic digestion of the enamel organ remains. All doses resulted in a hypomineralized incremental band corresponding to the position of the mineralizing front at the time of injection. At 5 and 10 mg P/kg body wt, a hypomineralized lesion was found throughout the whole thickness of the enamel in an area which corresponded to the stage of late enamel secretion at the time of injection. The surface layer covering this lesion was elevated or disrupted. By scanning electron microscopy, there were three different types of lesions along the enamel surface: a "demarcation groove" corresponding to the initial enamel formation at the time of injection; an "area containing mineral globules" and a "bright band" corresponding to the stages of late secretory and final enamel formation, respectively, at the time of injection. A single injection of HEBP thus interferes with different stages of enamel formation. The findings may be explained as of the physico-chemical effects of HEBP on the mineral phase alone, but a direct effect of the drug on ameloblast function cannot be excluded. PMID:2126428

Weile, V; Josephsen, K; Fejerskov, O

1990-01-01

326

Congenitally Missing Maxillary Lateral Incisors: Update on the Functional and Esthetic Parameters of Patients Treated with Implants or Space Closure and Teeth Recontouring  

PubMed Central

Maxillary lateral incisor agenesis (MLIA) is a condition that affects both dental esthetics and function in young patients, and represents an important challenge for clinicians. Although several treatment options are available, the mesial repositioning of the canines followed by teeth recontouring into lateral incisors; or space opening/maintenance followed by implant placement have recently emerged as two important treatment approaches. In this article, the current and latest literature has been reviewed in order to summarize the functional and esthetic outcomes obtained with these two forms of treatment of MLIA patients in recent years. Indications, clinical limitations and the most important parameters to achieve the best possible results with each treatment modality are also discussed. Within the limitations of this review, it is not possible to assert at this point in time that one treatment approach is more advantageous than the other. Long-term followup studies comparing the existing treatment options are still lacking in the literature, and they are necessary to shed some light on the issue. It is possible, however, to state that adequate multidisciplinary diagnosis and planning are imperative to define the treatment option that will provide the best individual results for patients with MLIA. PMID:25646137

Pini, Núbia Inocencya Pavesi; Marchi, Luciana Manzotti De; Pascotto, Renata Corrêa

2015-01-01

327

Validation and future predictions based on a new Non-Point Source Assessment Toolbox, applied to the Central Valley, California  

NASA Astrophysics Data System (ADS)

Groundwater is a major irrigation water source in semi-arid regions. It is also vulnerable to Non-Point Source (NPS) contamination, particularly from nitrate (NO3-) as a result of agricultural practices. To support sound policy decisions we developed a physically based flow and transport model framework to understand and predict the fate of contaminants within regional aquifer systems. In large aquifers, the total source area of pollutants typically cover several thousand square kilometers, whilst individual sources typically do not exceed a few hundred square meters. The large contrast in these scenarios result in NPS modeling tasks that are computationally demanding, and the classical 3D models that solve the Advection-Dispersion Equation (ADE) are often not applicable due to computer memory limitations, numerical dispersion and numerical instabilities. Here, we developed and employed a number of numerical techniques to assemble a Non-Point Source Assessment Toolbox (NPSAT). The NPSAT is a quasi-3D model, combining a flow model and a streamline transport model. The flow model solves the groundwater flow equation using very fine discretization. For very large groundwater basins, a simplistic decomposition method is applied, splitting the aquifer into several overlapping sub-domains and solving to produce a high resolution velocity field. This velocity field is subsequently utilized within the transport model, where backward particle tracking links contamination sources with discharge surfaces using a large number of streamlines. For each streamline the 1D ADE is solved, assuming a unit pulse loading at the source side and a free exit boundary condition at the discharge surface side. From this, a Unit Response Function (URF) is obtained at the discharge surface side. Subsequently, actual Breakthrough Curves (BTCs) can be quickly computed from actual or hypothetical loading histories, by convoluting the URFs with real loading functions. The URFs are stored into a GIS platform and can be used for efficient scenario evaluations without the need to repeat groundwater model simulations. This method is applied to the southern third part of the Central Valley Aquifer, California, which is an intensively farmed semi-arid area, where the local communities rely heavily on groundwater. To obtain a detailed velocity field, the Central Valley Hydrologic Model (CVHM) developed by the USGS was used as the coarse solution, split and refined into a large number of sub-domains. The CVHM resolution is 1 sq mi, with the stresses applied to the center of each cell. In our refined model the well stresses are spatially distributed to a large number of hypothetical wells, where the pumping rates, well depths and screen lengths are obtained from empirical probability distributions, derived from real data. The NPSAT generates a time-dependent water quality probability distribution, which express the time-dependent probability for a discharge surface (e.g., well) to exceed a threshold level of contamination across at a specific time. The model result is compared against real historic nitrate data, and used for future predictions with different scenario evaluations.

Kourakos, G.; Harter, T.

2011-12-01

328

Neuroarchitecture and neuroanatomy of the Drosophila central complex: A GAL4-based dissection of protocerebral bridge neurons and circuits.  

PubMed

Insects exhibit an elaborate repertoire of behaviors in response to environmental stimuli. The central complex plays a key role in combining various modalities of sensory information with an insect's internal state and past experience to select appropriate responses. Progress has been made in understanding the broad spectrum of outputs from the central complex neuropils and circuits involved in numerous behaviors. Many resident neurons have also been identified. However, the specific roles of these intricate structures and the functional connections between them remain largely obscure. Significant gains rely on obtaining a comprehensive catalog of the neurons and associated GAL4 lines that arborize within these brain regions, and on mapping neuronal pathways connecting these structures. To this end, small populations of neurons in the Drosophila melanogaster central complex were stochastically labeled using the multicolor flip-out technique and a catalog was created of the neurons, their morphologies, trajectories, relative arrangements, and corresponding GAL4 lines. This report focuses on one structure of the central complex, the protocerebral bridge, and identifies just 17 morphologically distinct cell types that arborize in this structure. This work also provides new insights into the anatomical structure of the four components of the central complex and its accessory neuropils. Most strikingly, we found that the protocerebral bridge contains 18 glomeruli, not 16, as previously believed. Revised wiring diagrams that take into account this updated architectural design are presented. This updated map of the Drosophila central complex will facilitate a deeper behavioral and physiological dissection of this sophisticated set of structures. J. Comp. Neurol. 523:997-1037, 2015. © 2014 Wiley Periodicals, Inc. PMID:25764203

Wolff, Tanya; Iyer, Nirmala A; Rubin, Gerald M

2015-05-01

329

Neuroarchitecture and neuroanatomy of the Drosophila central complex: A GAL4-based dissection of protocerebral bridge neurons and circuits.  

PubMed

Insects exhibit an elaborate repertoire of behaviors in response to environmental stimuli. The central complex plays a key role in combining various modalities of sensory information with an insect's internal state and past experience to select appropriate responses. Progress has been made in understanding the broad spectrum of outputs from the central complex neuropils and circuits involved in numerous behaviors. Many resident neurons have also been identified. However, the specific roles of these intricate structures and the functional connections between them remain largely obscure. Significant gains rely on obtaining a comprehensive catalog of the neurons and associated GAL4 lines that arborize within these brain regions, and on mapping neuronal pathways connecting these structures. To this end, small populations of neurons in the Drosophila melanogaster central complex were stochastically labeled using the multicolor flip-out technique and a catalog was created of the neurons, their morphologies, trajectories, relative arrangements, and corresponding GAL4 lines. This report focuses on one structure of the central complex, the protocerebral bridge, and identifies just 17 morphologically distinct cell types that arborize in this structure. This work also provides new insights into the anatomical structure of the four components of the central complex and its accessory neuropils. Most strikingly, we found that the protocerebral bridge contains 18 glomeruli, not 16, as previously believed. Revised wiring diagrams that take into account this updated architectural design are presented. This updated map of the Drosophila central complex will facilitate a deeper behavioral and physiological dissection of this sophisticated set of structures. J. Comp. Neurol. 523:997-1037, 2015. © 2014 Wiley Periodicals, Inc. PMID:25380328

Wolff, Tanya; Iyer, Nirmala A; Rubin, Gerald M

2015-05-01

330

Adapting to Climate Variability and Change: Experiences from Cereal-Based Farming in the Central Rift and Kobo Valleys, Ethiopia  

NASA Astrophysics Data System (ADS)

Small-holder farmers in Ethiopia are facing several climate related hazards, in particular highly variable rainfall with severe droughts which can have devastating effects on their livelihoods. Projected changes in climate are expected to aggravate the existing challenges. This study examines farmer perceptions on current climate variability and long-term changes, current adaptive strategies, and potential barriers for successful further adaptation in two case study regions—the Central Rift Valley (CRV) and Kobo Valley. The study was based on a household questionnaire, interviews with key stakeholders, and focus group discussions. The result revealed that about 99 % of the respondents at the CRV and 96 % at the Kobo Valley perceived an increase in temperature and 94 % at CRV and 91 % at the Kobo Valley perceived a decrease in rainfall over the last 20-30 years. Inter-annual and intraseasonal rainfall variability also has increased according to the farmers. The observed climate data (1977-2009) also showed an increasing trend in temperature and high inter-annual and intra-seasonal rainfall variability. In contrast to farmers’ perceptions of a decrease in rainfall totals, observed rainfall data showed no statistically significant decline. The interaction among various bio-physical and socio-economic factors, changes in rainfall intensity and reduced water available to crops due to increased hot spells, may have influenced the perception of farmers with respect to rainfall trends. In recent decades, farmers in both the CRV and Kobo have changed farming practices to adapt to perceived climate change and variability, for example, through crop and variety choice, adjustment of cropping calendar, and in situ moisture conservation. These relatively low-cost changes in farm practices were within the limited adaptation capacity of farmers, which may be insufficient to deal with the impacts of future climate change. Anticipated climate change is expected to impose new risks outside the range of current experiences. To enable farmers to adapt to these impacts critical technological, institutional, and market-access constraints need to be removed. Inconsistencies between farmers’ perceptions and observed climate trends (e.g., decrease in annual rainfall) could lead to sub-optimal or counterproductive adaptations, and therefore must be removed by better communication and capacity building, for example through Climate Field Schools. Enabling strategies, which are among others targeted at agricultural inputs, credit supply, market access, and strengthening of local knowledge and information services need to become integral part of government policies to assist farmers to adapt to the impacts of current and future climate change.

Kassie, Belay Tseganeh; Hengsdijk, Huib; Rötter, Reimund; Kahiluoto, Helena; Asseng, Senthold; Van Ittersum, Martin

2013-11-01

331

Pedostratigraphy of pre-Quaternary/Quaternary red paleosols from Central Europe based on geochemical and clay mineralogical proxies  

NASA Astrophysics Data System (ADS)

Geochemical and mineralogical studies of paleosols provide essential information for paleoclimatic and paleoenvironmental interpretation of continental deposits and can present a high-resolution proxy for paleoclimate. Consequently, paleosols can help to interpret the history of sediment deposition and the autogenic and allogenic processes that influenced a sedimentary basin. Paleosols are also helpful in stratigraphic studies, including sequence stratigraphic analyses. They are used for stratigraphic correlations at the local and basinal scale, and some workers have calculated sediment accumulation rates based on the degree of paleosol development. The horizons of paleosols are widely used as key horizons for the stratigraphic subdivision of continental sedimentary series. The reliability of usage of paleopedologic data has increased, especially with the development of methods of absolute and relative dating: radiocarbon, luminescent, paleomagnetic, amino acid, and paleontological (palynological and paleofaunistic) with geochemical and clay mineralogical data. The use of paleosols as components of the stratigraphic record has increased, especially after paleosols morphotypical features of different ages were studied. Paleosols in various sediment sections were once compound units of soil covers of different ages. Results from geochemical climofunctions applied to Upper Pliocene-Lower Pleistocene red clays and paleosols located in East-Central Europe (Austria, Slovakia, Hungary, Serbia and Romania) together with other geochemical data, clay mineralogy and fossil record, indicate that there were three major periods of their development. 1. The older type red clay/paleosol (age ~4.2-3.2 Ma) is red kaolinitic clay containing typically disordered kaolinite, mixed-layer smectite/kaolinite, smectite and little gibbsite. It was formed in the local subaerial weathering crust in warm, humid, subtropical or monsoon climate. 2. The younger type (age ~3.2-2.5 Ma) contains red (or "reddish") clay beds. It contains relatively fresh material (illite, chlorite), the weathering products are predominantly smectite and goethite formed under warm and drier climate in environmental conditions of savannah and steppe or forest steppe. 3. The basal red paleosol layer of the loess-paleosol series (age ~1.0-0.5 Ma) contain similar material as the 2nd type. The slightly but significantly lesser degree of weathering (more illite and chlorite, less smectite) indicates cooling of the climate. This contribution was made possible through financial support by 'Developing Competitiveness of Universities in the South Transdanubian Region (SROP-4.2.1.B-10/2/KONV-2010-0002)' and Austrian Agency for International Education & Research, financed by the Scholarship Foundation of the Republic of Austria (OeAD). It was additionally supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences for G. Újvári.

Kovács, János; Újvári, Gábor; Seelos, Klemens; Varga, György; Ottner, Franz; Lukoczki, Georgina

2013-04-01

332

Constraining the magma flow record based on magmatic and magnetic data in La Gloria Pluton, central Chile  

NASA Astrophysics Data System (ADS)

The magmatic origin of the anisotropy of magnetic susceptibility (AMS) is examined in comparison with magmatic anisotropy data in a small, shallow, silicic magma reservoir in the upper crust. La Gloria Pluton (LGP) is a 10 Ma granodiorite/quartz monzonite of about 250 km3 located in the southern Andes, central Chile. LGP represents a particularly simple case of a silicic intrusion that was assembled in only a few pulses and cooled over a short time interval. Hornblende, biotite and minor magnetite are ubiquitous mafic phases. The AMS tensor indicates that magnetic fabric has an oblate shape (i.e. magnetic foliation is higher than magnetic lineation). Lineations are weak (values up to 1.05), have a N-NW trend with a nearly horizontal dip and are interpreted to represent axisymmetric convection parallel to the main pluton elongation. Foliations are more pronounced (values up to 1.14), having NW trends and dips that vary gradually from vertical at the walls, to horizontal at the center and near the roof of the chamber. We selected 12 samples from AMS sites to obtain petrographic data (well-distributed throughout the pluton, containing samples from the walls, the center and the roof of LGP), and then, determine the magmatic fabric (anisotropy, lineation, foliation). We made 3 oriented thin sections per sample oriented with the AMS. Magmatic anisotropy data were obtained by measuring mineral length, width and orientation in photomicrographs of the three main planes of the AMS tensor, producing 3-D mineral data which were collected for plagioclase and amphibole + bitotite independently. For each site, a Bingham distribution with 95% of confidence is used to determine the mean mineral orientations and their angle difference with the AMS axes. Magmatic anisotropy tensor and rotations with respect to the AMS tensor are determined using both eigenvalues and minimization algorithms. Preliminary results indicate that crystals are coherently oriented in both mineral groups, and that magmatic anisotropy values are similar for all crystals and consistent with AMS data. Based on fluid dynamical numerical simulations of LGP, we interpret both magmatic and magnetic anisotropy as a consequence of shear during late magmatic convection, near the magma locking point along solidification fronts. Acknowledgments This research has been developed by the FONDECYT N°11100241 and PBCT-PDA07 projects granted by CONICYT (Chilean National Commission for Science and Technology). Gutierrez and Bachmann were supported by U.S. National Science Foundation (NSF) grant EAR-080982 during the completion of this research. Gelman was supported by U.S. National Science Foundation (NSF) grant DGE-0718124.

Gutierrez, F. J.; Payacán, I.; Gelman, S. E.; Bachmann, O.; Creative Physical Petrology Team

2013-05-01

333

Adapting to climate variability and change: experiences from cereal-based farming in the central rift and Kobo Valleys, Ethiopia.  

PubMed

Small-holder farmers in Ethiopia are facing several climate related hazards, in particular highly variable rainfall with severe droughts which can have devastating effects on their livelihoods. Projected changes in climate are expected to aggravate the existing challenges. This study examines farmer perceptions on current climate variability and long-term changes, current adaptive strategies, and potential barriers for successful further adaptation in two case study regions-the Central Rift Valley (CRV) and Kobo Valley. The study was based on a household questionnaire, interviews with key stakeholders, and focus group discussions. The result revealed that about 99 % of the respondents at the CRV and 96 % at the Kobo Valley perceived an increase in temperature and 94 % at CRV and 91 % at the Kobo Valley perceived a decrease in rainfall over the last 20-30 years. Inter-annual and intraseasonal rainfall variability also has increased according to the farmers. The observed climate data (1977-2009) also showed an increasing trend in temperature and high inter-annual and intra-seasonal rainfall variability. In contrast to farmers' perceptions of a decrease in rainfall totals, observed rainfall data showed no statistically significant decline. The interaction among various bio-physical and socio-economic factors, changes in rainfall intensity and reduced water available to crops due to increased hot spells, may have influenced the perception of farmers with respect to rainfall trends. In recent decades, farmers in both the CRV and Kobo have changed farming practices to adapt to perceived climate change and variability, for example, through crop and variety choice, adjustment of cropping calendar, and in situ moisture conservation. These relatively low-cost changes in farm practices were within the limited adaptation capacity of farmers, which may be insufficient to deal with the impacts of future climate change. Anticipated climate change is expected to impose new risks outside the range of current experiences. To enable farmers to adapt to these impacts critical technological, institutional, and market-access constraints need to be removed. Inconsistencies between farmers' perceptions and observed climate trends (e.g., decrease in annual rainfall) could lead to sub-optimal or counterproductive adaptations, and therefore must be removed by better communication and capacity building, for example through Climate Field Schools. Enabling strategies, which are among others targeted at agricultural inputs, credit supply, market access, and strengthening of local knowledge and information services need to become integral part of government policies to assist farmers to adapt to the impacts of current and future climate change. PMID:23943096

Kassie, Belay Tseganeh; Hengsdijk, Huib; Rötter, Reimund; Kahiluoto, Helena; Asseng, Senthold; Van Ittersum, Martin

2013-11-01

334

Isolated central nervous system metastases in patients with HER2-overexpressing advanced breast cancer treated with first-line trastuzumab-based therapy  

Microsoft Academic Search

Purpose: The aim of this study was to characterize the prevalence and predictors of central nervous system (CNS) metastasis among women with HER2-overexpressing metastatic breast cancer receiving trastuzumab-based therapy. Methods: The frequency and time course of isolated CNS progression were characterized among women with HER2-positive metastatic breast cancer, receiving chemotherapy with or without trastu- zumab as first-line treatment for metastatic

H. J. Burstein; G. Lieberman; D. J. Slamon; E. P. Winer; P. Klein

2005-01-01

335

Internal tectonic structure of the Central American Wadati-Benioff zone based on analysis of aftershock sequences  

Microsoft Academic Search

Relocated Engdahl et al. (1998) global seismological data for 10 aftershock sequences were used to analyze the internal tectonic structure of the Central American subduction zone; the main shocks of several of these were the most destructive and often referenced earthquakes in the region (e.g., the 1970 Chiapas, 1983 Osa, 1992 Nicaragua, 1999 Quepos, 2001 El Salvador earthquakes). The spatial

Ales Spicák; Václav Hanus; Jirí Vanek; Marie Behounková

2007-01-01

336

The application of GIS-based logistic regression for landslide susceptibility mapping in the Kakuda-Yahiko Mountains, Central Japan  

Microsoft Academic Search

As a first step forward in regional hazard management, multivariate statistical analysis in the form of logistic regression was used to produce a landslide susceptibility map in the Kakuda-Yahiko Mountains of Central Japan. There are different methods to prepare landslide susceptibility maps. The use of logistic regression in this study stemmed not only from the fact that this approach relaxes

Lulseged Ayalew; Hiromitsu Yamagishi

2005-01-01

337

Discovery of a Series of Efficient, Centrally Efficacious BACE1 Inhibitors through Structure-Based Drug Design.  

PubMed

The identification of centrally efficacious ?-secretase (BACE1) inhibitors for the treatment of Alzheimer's disease (AD) has historically been thwarted by an inability to maintain alignment of potency, brain availability, and desired absorption, distribution, metabolism, and excretion (ADME) properties. In this paper, we describe a series of truncated, fused thioamidines that are efficiently selective in garnering BACE1 activity without simultaneously inhibiting the closely related cathepsin D or negatively impacting brain penetration and ADME alignment, as exemplified by 36. Upon oral administration, these inhibitors exhibit robust brain availability and are efficacious in lowering central Amyloid ? (A?) levels in mouse and dog. In addition, chronic treatment in aged PS1/APP mice effects a decrease in the number and size of A?-derived plaques. Most importantly, evaluation of 36 in a 2-week exploratory toxicology study revealed no accumulation of autofluorescent material in retinal pigment epithelium or histology findings in the eye, issues observed with earlier BACE1 inhibitors. PMID:25695670

Butler, Christopher R; Brodney, Michael A; Beck, Elizabeth M; Barreiro, Gabriela; Nolan, Charles E; Pan, Feng; Vajdos, Felix; Parris, Kevin; Varghese, Alison H; Helal, Christopher J; Lira, Ricardo; Doran, Shawn D; Riddell, David R; Buzon, Leanne M; Dutra, Jason K; Martinez-Alsina, Luis A; Ogilvie, Kevin; Murray, John C; Young, Joseph M; Atchison, Kevin; Robshaw, Ashley; Gonzales, Cathleen; Wang, Jinlong; Zhang, Yong; O'Neill, Brian T

2015-03-26

338

Phylogenetic analysis of porcine epidemic diarrhea virus (PEDV) field strains in central China based on the ORF3 gene and the main neutralization epitopes.  

PubMed

Since 2010, porcine epidemic diarrhea has re-emerged with devastating impact on the swine-raising industry in central China. To investigate the epidemic characteristics of PEDV, the complete ORF3 genes of 14 PEDV field strains from central China during 2012 to 2013 were cloned, sequenced and compared with reference strains. Phylogenetic analysis based on the complete ORF3 gene showed that the PEDVs in central China and the reference strains could be divided into three groups: G1, G2, and G3. The 14 PEDV isolates were classified as G1 and showed a close relationship to some Chinese strains isolated previously in central China and differed genetically from recent isolates from southern China, Korean strains (SM98 and DB1865, 2012), the Chinese LZC strain (2007), and the vaccine strain (CV777) being used in China. Our findings suggested that the PEDVs circulating between 2012 and 2013 in central China might have evolved from earlier strains in the local region. To determine the reason for recent vaccination failures, we also studied variations in antigenicity of field strains by analyzing the three neutralizing epitope regions in the S gene. The results showed that the neutralizing epitopes at aa 245-252 were highly conserved, but most of the amino acid changes occurred in the epitope regions aa 7-146 and 271-278. We speculate that the amino acid mutations in the neutralizing epitope regions may be associated with changes in the antigenicity of PEDV and consequently result in vaccination failure. Together, these findings may be useful for understanding the epidemiology of PEDV and may be relevant for designing of new and more efficacious vaccines. PMID:24292967

Li, Renfeng; Qiao, Songlin; Yang, Yanyan; Su, Yunfang; Zhao, Pu; Zhou, Enmin; Zhang, Gaiping

2014-05-01

339

Coffee agroforestry systems in Central America: II. Development of a simple process-based model and preliminary results  

Microsoft Academic Search

Research on coffee agroforestry systems in Central America has identified various environmental factors, management strategies\\u000a and plant characteristics that affect growth, yield and the impact of the systems on the environment. Much of this literature\\u000a is not quantitative, and it remains difficult to optimise growing area selection, shade tree use and management. To assist\\u000a in this optimisation we developed a

Marcel van Oijen; Jean Dauzat; Jean-Michel Harmand; Gerry Lawson; Philippe Vaast

2010-01-01

340

Annual reproductive cycle based on histological changes in the ovary of the female mosquitofish, Gambusia affinis , in central Japan  

Microsoft Academic Search

To clarify the annual reproductive cycle of wild female mosquitofish,Gambusia affinis, in Mie Prefecture, central Japan, changes in ovarian histology were investigated. Female mosquitofish kept in aquaria under\\u000a constant temperature (25?C) and photoperiod (16L: 8D) conditions produced successive broods at intervals of 22.1?0.46 days\\u000a (n=7). Between days 0–3 following parturition, females began active vitellogenesis. Between days 3–5, fully grown oocytes

Yasunori Koya; Takako Itazu; Mutsumi Inoue

1998-01-01

341

Estimation of Recurrence Interval of Large Earthquakes on the Central Longmen Shan Fault Zone Based on Seismic Moment Accumulation/Release Model  

PubMed Central

Recurrence interval of large earthquake on an active fault zone is an important parameter in assessing seismic hazard. The 2008 Wenchuan earthquake (Mw 7.9) occurred on the central Longmen Shan fault zone and ruptured the Yingxiu-Beichuan fault (YBF) and the Guanxian-Jiangyou fault (GJF). However, there is a considerable discrepancy among recurrence intervals of large earthquake in preseismic and postseismic estimates based on slip rate and paleoseismologic results. Post-seismic trenches showed that the central Longmen Shan fault zone probably undertakes an event similar to the 2008 quake, suggesting a characteristic earthquake model. In this paper, we use the published seismogenic model of the 2008 earthquake based on Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data and construct a characteristic seismic moment accumulation/release model to estimate recurrence interval of large earthquakes on the central Longmen Shan fault zone. Our results show that the seismogenic zone accommodates a moment rate of (2.7?±?0.3)?×?1017?N?m/yr, and a recurrence interval of 3900?±?400?yrs is necessary for accumulation of strain energy equivalent to the 2008 earthquake. This study provides a preferred interval estimation of large earthquakes for seismic hazard analysis in the Longmen Shan region. PMID:23878524

Zhang, Shimin

2013-01-01

342

Development of trigger-based semi-automated surveillance of ventilator-associated pneumonia and central line-associated bloodstream infections in a Dutch intensive care  

PubMed Central

Background Availability of a patient data management system (PDMS) has created the opportunity to develop trigger-based electronic surveillance systems (ESSs). The aim was to evaluate a semi-automated trigger-based ESS for the detection of ventilator-associated pneumonia (VAP) and central line-associated blood stream infections (CLABSIs) in the intensive care. Methods Prospective comparison of surveillance was based on a semi-automated ESS with and without trigger. Components of the VAP/CLABSI definition served as triggers. These included the use of VAP/CLABSI-related antibiotics, the presence of mechanical ventilation or an intravenous central line, and the presence of specific clinical symptoms. Triggers were automatically fired by the PDMS. Chest X-rays and microbiology culture results were checked only on patient days with a positive trigger signal from the ESS. In traditional screening, no triggers were used; therefore, chest X-rays and culture results had to be screened for all patient days of all included patients. Patients with pneumonia at admission were excluded. Results A total of 553 patients were screened for VAP and CLABSI. The incidence of VAP was 3.3/1,000 ventilation days (13 VAP/3,927 mechanical ventilation days), and the incidence of CLABSI was 1.7/1,000 central line days (24 CLABSI/13.887 central line days). For VAP, the trigger-based screening had a sensitivity of 92.3%, a specificity of 100%, and a negative predictive value of 99.8% compared to traditional screening of all patients. For CLABSI, sensitivity was 91.3%, specificity 100%, and negative predictive value 99.6%. Conclusions Pre-selection of patients to be checked for signs and symptoms of VAP and CLABSI by a computer-generated automated trigger system was time saving but slightly less accurate than conventional surveillance. However, this after-the-fact surveillance was mainly designed as a quality indicator over time rather than for precise determination of infection rates. Therefore, surveillance of VAP and CLABSI with a trigger-based ESS is feasible and effective. PMID:25646148

2014-01-01

343

Unusual polymorphism in new bent-shaped liquid crystals based on biphenyl as a central molecular core  

PubMed Central

Summary Bent-shaped mesogens possessing a biphenyl as a central core have been synthesized and the role of the terminal chain and the orientation of the ester as a linkage group have been investigated. For the studied molecular core we have established that both parameters play an important role for the mesomorphic properties. The polyfluoroalkyl terminal chain supports the formation of mesophases, and the introduction of a chiral lactate terminal chain destabilizes mesophases for the first type of mutual orientation of ester groups, attached to the central core. On the contrary, for the opposite orientation of esters, the terminal chain has no effect on the mesomorphic properties, and columnar phases have been found for all compounds. A unique phase sequence has been found for the mesogen with the fluorinated chain. A generalized tilted smectics, SmCG, have been observed in a temperature interval between two different lamellar SmCP phases and characterized by X-ray and dielectric measurements. The dielectric spectroscopy data are unique and presented for the first time in the SmCG phase providing new information about the molecular dynamics. PMID:24778734

Ková?ová, Anna; Sv?tlík, Svatopluk; Kozmík, Václav; Novotná, Vladimíra; Pociecha, Damian; Gorecka, Ewa; Podoliak, Natalia

2014-01-01

344

Glacial-eustatic sea-level fluctuation curve for Carboniferous-Permian boundary strata based on outcrops in the North American Midcontinent and North-Central Texas  

SciTech Connect

Based on lithologic and faunal analysis of uppermost Carboniferous through Lower Permian strata (Wabaunsee through lower Chase groups) exposed from southeastern Nebraska through north-central Oklahoma, a preliminary glacial-eustatic sea-level fluctuation curve is presented herein. In addition to the sea-level curve presented for the Midcontinent region, one for coeval outcropping strata (middle and upper Cisco Group) of the Eastern Shelf of the Midland Basin is also presented based on similar criteria. This sea-level curve is derived from new field studies as well as a refinement of earlier curves presented by Harrison (1973), and Boardman and Malinky (1985). The conclusion on the nature of the Carboniferous-Permian boundary strata cyclothems in the Midcontinent is mirrored by the results of that from North-Central Texas. Each of the primary biostratigraphically-based picks for the Carboniferous-Permian boundary coincide with either intermediate of major cycles in both study areas. Utilization of a glacial-eustatic maximum transgressive event for the Carboniferous-Permian boundary should result in a more correlatable level for intercontinental correlation.

Boardman, D.R. (Oklahoma State Univ., Stillwater, OK (United States). School of Geology)

1993-02-01

345

A mathematical model to design a lignocellulosic biofuel supply chain system with a case study based on a region in Central Texas.  

PubMed

This study formulates a model to maximize the profit of a lignocellulosic biofuel supply chain ranging from feedstock suppliers to biofuel customers. The model deals with a time-staged, multi-commodity, production/distribution system, prescribing facility locations and capacities, technologies, and material flows. A case study based on a region in Central Texas demonstrates application of the proposed model to design the most profitable biofuel supply chain under each of several scenarios. A sensitivity analysis identifies that ethanol (ETOH) price is the most significant factor in the economic viability of a lignocellulosic biofuel supply chain. PMID:21724388

An, Heungjo; Wilhelm, Wilbert E; Searcy, Stephen W

2011-09-01

346

Remote sensing and hydrological measurement based irrigation performance assessments in the upper Amu Darya Delta, Central Asia  

NASA Astrophysics Data System (ADS)

In the Aral Sea Basin, where the Central Asian countries compete for limited water resources, reliable information on the actual water use for eight million ha of irrigated land are rare. In this study, spatially distributed land use data, seasonal actual evapotranspiration, and reference evapotranspiration derived from multitemporal MODIS data were combined with in situ water flow measurements for irrigation performance assessments in the upper Amu Darya Delta. The functioning of the major irrigation and drainage which supplies an agricultural area of 270,000 ha in the Uzbek province Khorezm was analysed using water balancing and adequacy indicators of irrigation water use. An average relative evapotranspiration of 95% indicated fulfilled water demands and partly over-irrigation, whereas values below 75% disclosed inadequate water supply in distant parts of the irrigation system. On the other hand, immense water withdrawals of approximately 24,000 m3 ha-1 recorded at the system boundaries between April and September 2005 clearly exceeded the field water demands for cotton cultivation. Only 46% of the total irrigation amounts were consumed for crop production at field level. Throughout the vegetation period, approximately 58% of the total available water left the region as drainage water. Monthly observations of the depleted fraction and the drainage ratio highlighted drainage problems and rising groundwater levels at regional scale. In the most distant downstream subsystem, a high risk of groundwater and soil salinity during the main irrigation phase was found. A combination of high conveyance losses, hydraulic problems, direct linkages between irrigation and drainage, and low field application efficiencies were identified as major reasons for underperforming irrigation. The findings underlined the necessity of water saving and of reconsidering water distribution in Khorezm. The remote sensing approach was concluded as a reliable data basis for regular performance assessments for all irrigation systems in Central Asia.

Conrad, C.; Dech, S. W.; Hafeez, M.; Lamers, J. P. A.; Tischbein, B.

347

Model-Based Radiation Dose Correction for Yttrium-90 Microsphere Treatment of Liver Tumors With Central Necrosis  

SciTech Connect

Purpose: The objectives of this study were to model and calculate the absorbed fraction {phi} of energy emitted from yttrium-90 ({sup 90}Y) microsphere treatment of necrotic liver tumors. Methods and Materials: The tumor necrosis model was proposed for the calculation of {phi} over the spherical shell region. Two approaches, the semianalytic method and the probabilistic method, were adopted. In the former method, the range--energy relationship and the sampling of electron paths were applied to calculate the energy deposition within the target region, using the straight-ahead and continuous-slowing-down approximation (CSDA) method. In the latter method, the Monte Carlo PENELOPE code was used to verify results from the first method. Results: The fraction of energy, {phi}, absorbed from {sup 90}Y by 1-cm thickness of tumor shell from microsphere distribution by CSDA with complete beta spectrum was 0.832 {+-} 0.001 and 0.833 {+-} 0.001 for smaller (r{sub T} = 5 cm) and larger (r{sub T} = 10 cm) tumors (where r is the radii of the tumor [T] and necrosis [N]). The fraction absorbed depended mainly on the thickness of the tumor necrosis configuration, rather than on tumor necrosis size. The maximal absorbed fraction {phi} that occurred in tumors without central necrosis for each size of tumor was different: 0.950 {+-} 0.000, and 0.975 {+-} 0.000 for smaller (r{sub T} = 5 cm) and larger (r{sub T} = 10 cm) tumors, respectively (p < 0.0001). Conclusions: The tumor necrosis model was developed for dose calculation of {sup 90}Y microsphere treatment of hepatic tumors with central necrosis. With this model, important information is provided regarding the absorbed fraction applicable to clinical {sup 90}Y microsphere treatment.

Liu, Ching-Sheng [National PET/Cyclotron Center, Taipei Veterans General Hospital, Taipei, Taiwan (China); Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Lin, Ko-Han [Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Lee, Rheun-Chuan, E-mail: rclee@vghtpe.gov.tw [Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan (China); Tseng, Hsiou-Shan [Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan (China); Wang, Ling-Wei; Huang, Pin-I; Chao, Liung-Sheau [Cancer Therapy Center, Taipei Veterans General Hospital, Taipei, Taiwan (China); Chang, Cheng-Yen [Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan (China); Yen, Sang-Hue [Cancer Therapy Center, Taipei Veterans General Hospital, Taipei, Taiwan (China); Tung, Chuan-Jong [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan (China); Wang, Syh-Jen [National PET/Cyclotron Center, Taipei Veterans General Hospital, Taipei, Taiwan (China); Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Oliver Wong, Ching-yee [Department of Nuclear Medicine and PET/Cyclotron Center, Oakland University William Beaumont School of Medicine Hospital, Royal Oak, Michigan (United States); Liu, Ren-Shyan [National PET/Cyclotron Center, Taipei Veterans General Hospital, Taipei, Taiwan (China); Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China)

2011-11-01

348

Experiences from near-real-time satellite-based volcano monitoring in Central America: case studies at Fuego, Guatemala  

Microsoft Academic Search

Over the past decade, remote sensing has been used increasingly in the study of active volcanoes and their associated hazards. Ground?based remote sensing techniques, such as those aimed at the analysis of volcanic gases or fumarole temperatures, are now part of routine monitoring operations with additional satellite?based remote sensing methods. It is likely that the use of satellite?based systems will

P. W. Webley; M. J. Wooster; W. Strauch; J. A. Saballos; K. Dill; P. Stephenson; J. Stephenson; R. Escobar Wolf; O. Matias

2008-01-01

349

Central Park  

NSDL National Science Digital Library

As one of the worldâ??s greatest urban green spaces, Central Park is loved by dyed-in-the wool New Yorkers as well as visitors to the city. This reverential website provides detailed information about this fine public space and the activities that take place within its confines. On this site, visitors can look over maps of the park, learn about the parkâ??s many attractions, and browse a selection of photographs of this fine urban paradise. The homepage contains much of this material, along with a â??Central Park Newsâ? feature, which provides news updates about goings on throughout Central Park. For those planning a visit to the park, the Events area will be most useful, as it provides information about such pastimes as rock climbing, ice skating lessons, and yoga.

2006-01-01

350

An economic feasibility analysis of distributed electric power generation based upon the natural gas-fired fuel cell: a model of a central utility plant.  

SciTech Connect

This central utilities plant model details the major elements of a central utilities plant for several classes of users. The model enables the analyst to select optional, cost effective, plant features that are appropriate to a fuel cell application. These features permit the future plant owner to exploit all of the energy produced by the fuel cell, thereby reducing the total cost of ownership. The model further affords the analyst an opportunity to identify avoided costs of the fuel cell-based power plant. This definition establishes the performance and capacity information, appropriate to the class of user, to support the capital cost model and the feasibility analysis. It is detailed only to the depth required to identify the major elements of a fuel cell-based system. The model permits the choice of system features that would be suitable for a large condominium complex or a residential institution such as a hotel, boarding school or prison. The user may also select large office buildings that are characterized by 12 to 16 hours per day of operation or industrial users with a steady demand for thermal and electrical energy around the clock.

Not Available

1993-06-30

351

A detailed Holocene glacial-periglacial reconstruction based on multidisciplinary studies of a 60 m permafrost core from central Svalbard  

NASA Astrophysics Data System (ADS)

During summer 2012, a 60 m sedimentary permafrost core was retrieved from the lower part of the Adventdalen Valley, central Svalbard, as part of the Longyearbyen CO2 project. The core was taken in 3 m long sections, with 20 % core loss, and reached the sedimentary bedrock (Lower Cretaceous). Thus our samples had the potential to represent the entire Quaternary and reflect changes in the sedimentary environments through time. The stratigraphy and sedimentology of the core was first investigated, to establish an overall geological model for the sampling site. The general stratigraphy encompasses a layer of basal till at the bottom of the core. This is overlain by marine sediments documenting a transition from glacial-proximal to open-marine conditions. Subsequently, a thick package of deltaic sediments records the progradation of the local river system. Finally, aeolian sediments, characterizing the modern environment, form the top few meters of the core. The ice content of the permafrost is generally low. Gravimetric water content generally ranges between 20% and 40%, but is considerably higher in some ice-rich layers. High resolution optically stimulated luminescence dating of the core sediment shows that deposition was very fast and took place primarily during the mid Holocene, with very rapid sedimentation of around 4 m/ka. With the onset of aeolian deposition (around 3-4 ka) the sedimentation rate decreased significantly to 1m/ka. The microbial diversity and activity of the core are being studied displaying decreasing activity with depth. Microbial community and functional gene numbers indicate variations with depth and geochemistry. Incubation studies have been performed primarily on the upper 30 m, and indicate a potential CO2 production from all depth intervals being studied. The potential for using foraminifer studies for both dating and palaeoenvironmental reconstructions are evaluated with the intension of comparison with previous studies of marine sediment cores both from the fjords in the Svalbard area and from the Barents Sea and Fram Strait region. This multidisciplinary approach is allowing us to build the first detailed palaeoenvironmental reconstruction of the Holocene glacial-periglacial interaction in the lowlands of central Svalbard; this includes a detailed reconstruction of the permafrost conditions.

Hvidtfeldt Christiansen, Hanne; Elberling, Bo; Gilbert, Graham L.; Thiel, Christine; Murray, Andrew; Buylaert, Jan-Pieter; Dypvik, Henning; Lomstein, Bente; Hovgaard, Jonas; Christensen, Anne T.; Mørkved, Pål T.; Reigstad, Laila J.; Fromreide, Siren; Seidenkrantz, Marit-Solveig

2014-05-01

352

Numerical and experimental study on silicon microresonators based on phononic crystal slabs with reduced central-hole radii  

NASA Astrophysics Data System (ADS)

In this paper, we report the numerical and experimental study on micromechanical resonators which are made by introducing defects on an otherwise perfect two-dimensional (2D) silicon phononic crystal (PnC) slab. The 2D PnC slab is made by etching a square array of cylindrical air holes in a free-standing silicon plate with a thickness of 10 µm, while the defects are created by reducing the radii of three rows of air holes at the centre of the 2D PnC slab. Three resonators with different values of reduced radii, i.e., 2 µm, 4 µm and 6 µm, are included in this study. The finite-element-modelling method is used to calculate the band structure of the perfect 2D PnC slab and to analyse the different mode shapes of the structure. The design, numerical modelling, fabrication process, as well as characterization results and discussions of the three PnC resonators are also included. Due to its CMOS-compatibility, aluminium nitride is chosen to be the piezoelectric material of the inter-digital transducers, which are used to generate and detect acoustic waves. Testing is done to characterize the resonant frequency (f), quality factor (Q), as well as insertion loss of each of the three microfabricated PnC resonators and the results are discussed by analysing the simulated transmission spectra, the defected band structures, and the steady-state displacement profiles of the structures at their respective resonant frequencies. The experimental results show that the designed PnC resonators with reduced central-hole radii have higher resonant frequency and higher quality factors as compared to their normal Fabry-Perot counterpart, thanks to the higher-frequency modes supported within the cavity and slow sound effect in the lateral direction introduced by the central holes with reduced radii, respectively. As a result, the achieved (f-Q) product can be as high as 2.96 × 1011, which is among the highest for silicon resonators operating in air.

Wang, Nan; Hsiao, Fu-Li; Tsai, J. M.; Palaniapan, Moorthi; Kwong, Dim-Lee; Lee, Chengkuo

2013-06-01

353

Centralized Wavelength Monitoring\\/Stabilization Technique by Dithering Temperature of LD in Power-Splitter-Based WDM-PON  

Microsoft Academic Search

This paper proposes a simple and cost-effective wavelength monitoring\\/stabilization technique for upstream signals in a power-splitter-based dense WDM-PON. We present the concept and experimentally confirm the feasibility of this technique.

Masamichi Fujiwara; Hiro Suzuki; Naoto Yoshimoto; Takamasa Imai

2007-01-01

354

Uranium and thorium enrichment in rocks from the base of DSDP Hole 465A, Hess Rise, central North Pacific  

USGS Publications Warehouse

Uranium and thorium are concentrated in Cretaceous limestone, chert, ash, basalt, and other rock types at Deep Sea Drilling Project Site 465 located on the southern Hess Rise in the central North Pacific. U concentrations, up to 194 ppm on a carbonate-free basis, are among the highest recorded for any deep-sea deposits. U was initially derived from seawater and concentrated by absorption on terrigenous (humic) organic matter in limestone in a shallow marine environment. U and Th were probably concentrated further by low-temperature hydrothermal fluids emanating from the basaltic basement. Mainly montmorillonite, an alteration product of basalt and ash, and organic matter in sedimentary rocks acted as hosts for U and Th. The unique combination of sediments rich in humic organic matter, abundant smectite in altered ash and basalt, and warm hydrothermal solutions provided the necessary conditions for migration and concentration of U and Th. To better understand the conditions limiting the migrating and concentration of U and Th, other rocks deposited during the ocean-wide Cretaceous anoxic events should be analyzed for these elements. ?? 1982.

Hein, J.R.; Koski, R.A.; Morgenson, L.A.

1982-01-01

355

Mid to late holocene climate evolution of the lake telmen basin, north central mongolia, based on palynological data  

NASA Astrophysics Data System (ADS)

Palynological and sedimentological data from Lake Telmen, in north-central Mongolia, permit qualitative reconstruction of relative changes in moisture balance throughout the mid to late Holocene. The climate of the Atlantic period (7500-4500 yr ago) was relatively arid, indicating that Lake Telmen lay beyond the region of enhanced precipitation delivered by the expanded Asian monsoon. Maximum humidity is recorded between ˜4500 and 1600 cal yr B.P., during the Subboreal (4500-2500 yr ago) and early Subatlantic (2500 yr-present) periods. Additional humid intervals during the Medieval Warm Epoch (˜1000-1300 A.D. or 950-650 ago) and the Little Ice Age (1500- 1900 A.D. or 450-50 yr B.P.) demonstrate the lack of long-term correlation between temperature and moisture availability in this region. A brief aridification centered around 1410 cal yr B.P. encompasses a decade of cold temperatures and summer frost between A.D. 536 and 545 (1414-1405 yr B.P.) inferred from records of Mongolian tree-ring widths. These data suggest that steppe vegetation of the Lake Telmen region is sensitive to centennial- and decadal-scale climatic perturbations.

Fowell, Sarah J.; Hansen, Barbara C. S.; Peck, John A.; Khosbayar, P.; Ganbold, Enebish

2003-05-01

356

Modelling central metabolic fluxes by constraint-based optimization reveals metabolic reprogramming of developing Solanum lycopersicum (tomato) fruit  

PubMed Central

Modelling of metabolic networks is a powerful tool to analyse the behaviour of developing plant organs, including fruits. Guided by our current understanding of heterotrophic metabolism of plant cells, a medium-scale stoichiometric model, including the balance of co–factors and energy, was constructed in order to describe metabolic shifts that occur through the nine sequential stages of Solanum lycopersicum (tomato) fruit development. The measured concentrations of the main biomass components and the accumulated metabolites in the pericarp, determined at each stage, were fitted in order to calculate, by derivation, the corresponding external fluxes. They were used as constraints to solve the model by minimizing the internal fluxes. The distribution of the calculated fluxes of central metabolism were then analysed and compared with known metabolic behaviours. For instance, the partition of the main metabolic pathways (glycolysis, pentose phosphate pathway, etc.) was relevant throughout fruit development. We also predicted a valid import of carbon and nitrogen by the fruit, as well as a consistent CO2 release. Interestingly, the energetic balance indicates that excess ATP is dissipated just before the onset of ripening, supporting the concept of the climacteric crisis. Finally, the apparent contradiction between calculated fluxes with low values compared with measured enzyme capacities suggest a complex reprogramming of the metabolic machinery during fruit development. With a powerful set of experimental data and an accurate definition of the metabolic system, this work provides important insight into the metabolic and physiological requirements of the developing tomato fruits. PMID:25279440

Colombié, Sophie; Nazaret, Christine; Bénard, Camille; Biais, Benoît; Mengin, Virginie; Solé, Marion; Fouillen, Laëtitia; Dieuaide-Noubhani, Martine; Mazat, Jean-Pierre; Beauvoit, Bertrand; Gibon, Yves

2015-01-01

357

Modelling central metabolic fluxes by constraint-based optimization reveals metabolic reprogramming of developing Solanum lycopersicum (tomato) fruit.  

PubMed

Modelling of metabolic networks is a powerful tool to analyse the behaviour of developing plant organs, including fruits. Guided by our current understanding of heterotrophic metabolism of plant cells, a medium-scale stoichiometric model, including the balance of co-factors and energy, was constructed in order to describe metabolic shifts that occur through the nine sequential stages of Solanum lycopersicum (tomato) fruit development. The measured concentrations of the main biomass components and the accumulated metabolites in the pericarp, determined at each stage, were fitted in order to calculate, by derivation, the corresponding external fluxes. They were used as constraints to solve the model by minimizing the internal fluxes. The distribution of the calculated fluxes of central metabolism were then analysed and compared with known metabolic behaviours. For instance, the partition of the main metabolic pathways (glycolysis, pentose phosphate pathway, etc.) was relevant throughout fruit development. We also predicted a valid import of carbon and nitrogen by the fruit, as well as a consistent CO2 release. Interestingly, the energetic balance indicates that excess ATP is dissipated just before the onset of ripening, supporting the concept of the climacteric crisis. Finally, the apparent contradiction between calculated fluxes with low values compared with measured enzyme capacities suggest a complex reprogramming of the metabolic machinery during fruit development. With a powerful set of experimental data and an accurate definition of the metabolic system, this work provides important insight into the metabolic and physiological requirements of the developing tomato fruits. PMID:25279440

Colombié, Sophie; Nazaret, Christine; Bénard, Camille; Biais, Benoît; Mengin, Virginie; Solé, Marion; Fouillen, Laëtitia; Dieuaide-Noubhani, Martine; Mazat, Jean-Pierre; Beauvoit, Bertrand; Gibon, Yves

2015-01-01

358

@central park  

NSDL National Science Digital Library

The Central Park Conservancy, a not-for-profit organization dedicated to restoring, improving, and managing Central Park's grounds and facilities, offers this "official" site, which contains a wealth of information about what is arguably the world's most famous city park. Each of the site's sections contains useful or interesting information; the Then & Now section, for instance, offers an overview of Central Park's history, a bibliography with 43 entries for those seeking further information, and a list of movies with scenes set in the park. Another highlight of the site is the Virtual Park, which consists of a set of clickable maps through which users can explore 72 points of interest, each described in the affectionate style of a travel guidebook. The site's other sections include such features as events schedules, press releases, information on when and where particular varieties of flowers bloom, and a section devoted entirely to activities for families and children. This site will be especially useful to those who are planning a visit to Central Park, but other users will likely find it informative and entertaining as well.

359

Central Chile  

NASA Technical Reports Server (NTRS)

The beginning of spring in central Chile looked like this to SeaWiFS. The snow-covered Andes mark the country's eastern border, and phytoplankton blooms and river sediment plumes fill the waters off its west coast. A large eddy due west of Concepcion is highlighted by the phytoplankton it contains.

2002-01-01

360

Engineering Central  

NSDL National Science Digital Library

The Engineering Central website provides a plethora of listings of employment resources for engineers. The website allows users to submit their resume to a resume bank, browse through entry-level jobs, as well as post jobs online. Several links that point to other engineering resources are also provided.

361

Cicada Central  

NSDL National Science Digital Library

This site, hosted by University of Connecticut, "is designed to be a center for the exchange of scientific information concerning cicadas of the world." This Cicada Central website links to reprints for scientific literature concerning cicadas, a list of cicada researchers from around the world, a list of world cicada tribes, and more.

Simon, Chris

362

Halloween Central  

NSDL National Science Digital Library

Halloween is coming up, and this site will help readers prepare for an evening of ghouls, goblins, and other nasties. Halloween Central is a fairly extensive metasite with links to a wide variety of Halloween resources, including costumes, clip art, recipes, haunted houses, Halloween safety, and pumpkins, among many others.

363

The effect of a single dose of 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) on secretory ameloblasts and enamel formation in rat incisors.  

PubMed

The present experiment was undertaken in order to study how HEBP affects secretory ameloblasts and the mineralizing front of rat incisor enamel resulting in the formation of a hypomineralized incremental band. Rats were given a single subcutaneous injection of 10 mg/kg body weight of HEBP and sacrificed at intervals ranging from 1 hour to 9 days. The incisors were specially prepared for microradiography, scanning electron microscopy, and light and transmission electron microscopy. The microradiographical examination 9 days after injection revealed a distinct incremental band of hypomineralization from the amelo-dentinal junction to the outer enamel surface. The overall rod pattern and mineral distribution within the enamel was otherwise normal. Under light microscopy the ameloblasts exhibited an increase in vacuoles and dark granules in the supranuclear cytoplasm 2-12 hours after injection. At 12 hours a total disarray of the mineralizing front was evident and confirmed by SEM. However, 24 hours after injection a normal structure of the mineralizing front was regained. Ultrastructurally the organelles of the ameloblasts showed no changes from normal at any time interval. However, 2 hours after injection multivesicular bodies appeared frequently in the Tomes' processes and crystal density had diminished in the interrod enamel. At 8 hours a proteinaceous matrixdevoid of crystals was accumulating corresponding to interrod growth regions, whereas no obvious changes were recorded at the rod growth regions. At 12 hours the newly formed interrod enamel was thin and without crystals in some places. In such areas a granular, less-dense matrix was found and a band of small swellings of the interrod enamel was evident most likely corresponding to the time of injection. After 24 hours the cells and the mineralizing front appeared normal except in the interrod growth regions where the cell processes were still separated by wide intercellular spaces in which crystals were occasionally found in a fine granular matrix. These observations are discussed with particular reference on the known physico-chemical effects of HEBP on mineral formation. A possible direct cellular effect on the ameloblasts should be studied using radioautography and immunocytological techniques. PMID:2128888

Fejerskov, O; Josephsen, K; Weile, V

1990-12-01

364

The role of inherited structures in the evolution of the Meknassy Basin, Central Tunisia, based on geological-geophysical transects  

NASA Astrophysics Data System (ADS)

This paper uses seismic data, well data, and surface geologic data to present a detailed description of the Meknassy Basin in the Atlas fold and thrust belt of central Tunisia. These data reveal that the Meknassy Basin is bounded by major faults, along which Triassic evaporites have been intruded. The anticlines and synclines of the basin are delimited by two N-S main faults (the North-South Axis and the Sidi Ali Ben Oun fault) and are subdivided by associated N120° and N45° trending fault-related anticlines. The Meknassy Basin is characterized by brittle structures associated with a deep asymmetric geometry that is organized into depressions and uplifts. Halokinesis of Triassic evaporites began during the Jurassic and continued during the Cretaceous period. During extensional deformation, salt movement controlled the sediment accumulation and the location of pre-compressional structures. During compressional deformation, the remobilization of evaporites accentuated the folded uplifts. A zone of decollement is located within the Triassic evaporites. The coeval strike-slip motion along the bounding master faults suggests that the Meknassy Basin was initiated as a pull-apart basin with intrusion of Triassic evaporites. The lozenge structure of the basin was caused by synchronous movements of the Sidi Ali Ben Oun fault and the North-South Axis (sinistral wrench faults) with movement of NW-SE first-order dextral strike-slip faults. Sediment distribution and structural features indicate that a major tectonic inversion has occurred at least since Late Cretaceous and Cenozoic. The transpressional movements are marked by reverse faults and folds associated with unconformities and with remobilization of Triassic evaporites. The formation of different structural features and the evolution of the Meknassy Basin and its neighboring uplifts have been controlled by conjugate dextral and sinistral strike-slip movements and thrust displacement.

Haji, Taoufik; Zouaghi, Taher; Boukadi, Noureddine

2014-08-01

365

Quaternary paleoceanography of the central Arctic based on Integrated Ocean Drilling Program Arctic Coring Expedition 302 foraminiferal assemblages  

USGS Publications Warehouse

The Integrated Ocean Drilling Program (IODP) Arctic Coring Expedition (ACEX) Hole 4C from the Lomonosov Ridge in the central Arctic Ocean recovered a continuous 18 in record of Quaternary foraminifera yielding evidence for seasonally ice-free interglacials during the Matuyama, progressive development of large glacials during the mid-Pleistocene transition (MPT) ???1.2-0.9 Ma, and the onset of high-amplitude 100-ka orbital cycles ???500 ka. Foraminiferal preservation in sediments from the Arctic is influenced by primary (sea ice, organic input, and other environmental conditions) and secondary factors (syndepositional, long-term pore water dissolution). Taking these into account, the ACEX 4C record shows distinct maxima in agglutinated foraminiferal abundance corresponding to several interglacials and deglacials between marine isotope stages (MIS) 13-37, and although less precise dating is available for older sediments, these trends appear to continue through the Matuyama. The MPT is characterized by nearly barren intervals during major glacials (MIS 12, 16, and 22-24) and faunal turnover (MIS 12-24). Abundant calcareous planktonic (mainly Neogloboquadrina pachyderma sin.) and benthic foraminifers occur mainly in interglacial intervals during the Brunhes and very rarely in the Matuyama. A distinct faunal transition from calcareous to agglutinated foraminifers 200-300 ka in ACEX 4C is comparable to that found in Arctic sediments from the Lomonosov, Alpha, and Northwind ridges and the Morris Jesup Rise. Down-core disappearance of calcareous taxa is probably related to either reduced sea ice cover prior to the last few 100-ka cycles, pore water dissolution, or both. Copyright 2008 by the American Geophysical Union.

Cronin, T. M.; Smith, S.A.; Eynaud, F.; O'Regan, M.; King, J.

2008-01-01

366

Evaluation of Central North American prairie management based on species diversity, life form, and individual species metrics.  

PubMed

Reintroduction of fire and grazing, alone or in combination, has increasingly been recognized as central to the restoration of North American mixed-grass and tallgrass prairies. Although ecological studies of these systems are abundant, they have generally been observational, or if experimental, have focused on plant species diversity. Species diversity measures alone are not sufficient to inform management, which often has goals associated with life-form groups and individual species. We examined the effects of prescribed fire, light cattle grazing, and a combination of fire and grazing on three vegetation components: species diversity, groups of species categorized by life-form, and individual species. We evaluated how successful these three treatments were in achieving specific management goals for prairies in the Iowa Loess Hills (U.S.A.). The grazing treatment promoted the greatest overall species richness, whereas grazing and burning and grazing treatments resulted in the lowest cover by woody species. Burning alone best achieved the management goals of increasing the cover and diversity of native species and reducing exotic forb and (predominantly exotic) cool-season grass cover. Species-specific responses to treatments appeared idiosyncratic (i.e., within each treatment there existed a set of species attaining their highest frequency) and nearly half of uncommon species were present in only one treatment. Because all management goals were not achieved by any one treatment, we conclude that management in this region may need refining. We suggest that a mosaic of burning and grazing (alone and in combination) may provide the greatest landscape-level species richness; however, this strategy would also likely promote the persistence of exotic species. Our results support the need to consider multiple measures, including species-specific responses, when planning and evaluating management. PMID:17531063

Brudvig, Lars A; Mabry, Catherine M; Miller, James R; Walker, Tracy A

2007-06-01

367

Phosphatic glauconitic sandstone and oncolite deposition at the Upper Paleozoic base of Etivuluk Group, North-Central Brooks Range, Alaska  

SciTech Connect

Carboniferous stratigraphy of the Picnic Creek allochthon in the central Brooks Range is dominated by bedded cherts and shales. In the Killik River quadrangle, bedded black cherts of the Lisburne Group are overlain by a thin diagnostic clastic unit composed of sandstone and conglomerate. The sandstone is a thin (0.35-m), laterally extensive, planar, laminated litharenite with an average Q:F:L of 40:17:43 and a Qp:Lv:Ls of 12:8:80. The provenance is interpreted to be a recycled orogen dominated by uplifted sedimentary sequences with minor plutonic, metamorphic, and volcanic sources. The presence of glauconite (7%) and authigenic phosphate (18%) indicates deposition in a shelf environment. This phosphatic sandstone forms part of the matrix in a conglomerate at one locality. The conglomerate is lenticular (2 m X 10 m), crudely graded, and very poorly sorted, and it contains black chert ripups. Clasts are composed of onscoids (70%), chert (22%), shale (5%), and limestone (3%). Barite preferentially replaces all clasts except chert and part of the matrix. The oncolites are SS-type mode C hemispheroids, indicating formation in a continuously agitated shallow to intertidal marine environment. Sedimentologic and petrographic observations suggest that the phosphatic glauconitic sandstone developed in a shelf environment, and the oncolitic conglomerate is a debris flow off a nearby carbonate platform that transported shallow-water material out onto the shelf. Preservation of unaltered echinoderm fragments and calcareous algal oncolites clearly indicates deposition above the CCD. Radiolarians from immediately above the clastics include spongy tetrahedral Latentifistulidea, which suggests that sandstone and conglomerate deposition probably occurred in the Morrowan (Early Pennsylvanian).

Siok, J.P.; Mull, C.G.

1985-04-01

368

Risk mapping of Rinderpest sero-prevalence in Central and Southern Somalia based on spatial and network risk factors  

Microsoft Academic Search

BACKGROUND: In contrast to most pastoral systems, the Somali livestock production system is oriented towards domestic trade and export with seasonal movement patterns of herds\\/flocks in search of water and pasture and towards export points. Data from a rinderpest survey and other data sources have been integrated to explore the topology of a contact network of cattle herds based on

Angel Ortiz-Pelaez; Dirk U Pfeiffer; Stefano Tempia; F Tom Otieno; Hussein H Aden; Riccardo Costagli

2010-01-01

369

A Central Support System Can Facilitate Implementation and Sustainability of a Classroom-Based Undergraduate Research Experience (CURE) in Genomics  

ERIC Educational Resources Information Center

In their 2012 report, the President's Council of Advisors on Science and Technology advocated "replacing standard science laboratory courses with discovery-based research courses"--a challenging proposition that presents practical and pedagogical difficulties. In this paper, we describe our collective experiences working with the…

Lopatto, David; Hauser, Charles; Jones, Christopher J.; Paetkau, Don; Chandrasekaran, Vidya; Dunbar, David; MacKinnon, Christy; Stamm, Joyce; Alvarez, Consuelo; Barnard, Daron; Bedard, James E. J.; Bednarski, April E.; Bhalla, Satish; Braverman, John M.; Burg, Martin; Chung, Hui-Min; DeJong, Randall J.; DiAngelo, Justin R.; Du, Chunguang; Eckdahl, Todd T.; Emerson, Julia; Frary, Amy; Frohlich, Donald; Goodman, Anya L.; Gosser, Yuying; Govind, Shubha; Haberman, Adam; Hark, Amy T.; Hoogewerf, Arlene; Johnson, Diana; Kadlec, Lisa; Kaehler, Marian; Key, S. Catherine Silver; Kokan, Nighat P.; Kopp, Olga R.; Kuleck, Gary A.; Lopilato, Jane; Martinez-Cruzado, Juan C.; McNeil, Gerard; Mel, Stephanie; Nagengast, Alexis; Overvoorde, Paul J.; Parrish, Susan; Preuss, Mary L.; Reed, Laura D.; Regisford, E. Gloria; Revie, Dennis; Robic, Srebrenka; Roecklien-Canfield, Jennifer A.; Rosenwald, Anne G.; Rubin, Michael R.; Saville, Kenneth; Schroeder, Stephanie; Sharif, Karim A.; Shaw, Mary; Skuse, Gary; Smith, Christopher D.; Smith, Mary; Smith, Sheryl T.; Spana, Eric P.; Spratt, Mary; Sreenivasan, Aparna; Thompson, Jeffrey S.; Wawersik, Matthew; Wolyniak, Michael J.; Youngblom, James; Zhou, Leming; Buhler, Jeremy; Mardis, Elaine; Leung, Wilson; Shaffer, Christopher D.; Threlfall, Jennifer; Elgin, Sarah C. R.

2014-01-01

370

GROUND BASED LIDAR OBSERVATIONS OF AEROSOL AND CIRRUS CLOUDS OPTICAL PROPERTIES IN CENTRAL AMAZON DURING THE DRY SEASON  

E-print Network

to perform continuous measurements of aerosols and water vapor and aiming to study and monitor the atmosphere season were analysed as a mean to assess the overall system capability and performance of the algorithms. From the same dataset, our automatic algorithm based on [3] identified Cirrus clouds in 60% of our

Barbosa, Henrique

371

How Central and Connected Am I in My Family? Family-Based Social Capital of Individuals with Intellectual Disability  

ERIC Educational Resources Information Center

Using social network methods, this article explores the ways in which individuals with intellectual disability (ID) perceive their family contexts and the social capital that they provide. Based on a subsample of 24 individuals with ID, a subsample of 24 individuals with ID and psychiatric disorders, and a control sample of 24 pre-graduate and…

Widmer, E. D.; Kempf-Constantin, N.; Robert-Tissot, C.; Lanzi, F.; Carminati, G. Galli

2008-01-01

372

Controls on mineralisation in the Sierra Foothills gold province, central California, USA: a GIS-based reconnaissance prospectivity analysis  

Microsoft Academic Search

The assessment of spatial relationships between the location, abundance and size of orogenic-gold deposits in the highly endowed Sierra Foothills gold province in California, via the combination of field studies and a GIS-based analysis, illustrates the power of such an approach to the characterisation of important parameters of mineral systems, and the prediction of districts likely to host economic mineralisation.

F. P. Bierlein; H. J. Northover; D. I. Groves; R. J. Goldfarb; E. E. Marsh

2008-01-01

373

Grief-Processing-Based Psychological Intervention for Children Orphaned by AIDS in Central China: A Pilot Study  

ERIC Educational Resources Information Center

A group of 124 children orphaned by AIDS (COA), who resided in two orphanages funded by the Chinese government, participated in a study investigating the efficacy of a grief-processing-based psychological group intervention. This psychological intervention program was designed to specifically help COA process their grief and reduce their…

Lin, Xiuyun; Fang, Xiaoyi; Chi, Peilian; Li, Xiaoming; Chen, Wenrui; Heath, Melissa Allen

2014-01-01

374

Garlic Central  

NSDL National Science Digital Library

Can garlic help repel mosquitoes? Find out the answer to this question and more at Garlic Central, an all-about-garlic website created by aficionado Trevor Mendham. The site contains an introductory section--titled Garlic 101--and sections that address culinary uses, medicinal benefits, and cultivation. The site's Cooking section includes a collection of recipes; and information about storing, freezing, and crushing garlic. The site also features a brief how-to guide for planting, growing, and harvesting garlic. Garlic Central even hosts a virtual shopping mall that connects site visitors to a wide range of garlic-related websites peddling foodstuffs, kitchen implements, posters, books, and garden supplies. This site is also reviewed in the September 17, 2004 _NSDL Life Sciences Report_.

375

A transtensional basin model for the Organyà basin (central southern Pyrenees) based on magnetic fabric and brittle structures  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to explain the kinematics of the inverted extensional Organyà basin (Central Southern Pyrenees) during its extensional evolution. The study of the anisotropy of magnetic susceptibility (AMS) and the study of brittle mesostructures are the instruments used to decipher the extensional kinematics. Separation of magnetic subfabrics (analyses of AMS at low temperature and anisotropy of the anhysteretic remanence - AARM) has been also done to properly interpret the obtained magnetic fabric data. The combination of all magnetic fabric and brittle mesostructures analyses has provided new information to clarify the structural evolution of the basin, which support a new tectonic model for the Aptian-Albian basinal stage. 20 sites for the magnetic fabric analysis were sampled in Aptian-Lower Albian marls. The AMS ellipsoids obtained at room temperature show their kmin axes perpendicular to bedding and kmax axes oriented NW-SE in 70 per cent of the samples, N-S in 15 per cent and NE-SW in 15 per cent. Analyses of AMS at low temperature show a better clustering of the axes of the magnetic ellipsoid pointing out that phyllosilicates constitute the carriers of the AMS, whereas the analyses of the AARM confirm the scattering of the ferromagnetic grains. These results suggest that the obtained AMS in the Organyà basin was acquired during or shortly after deposition of the Aptian-Lower Albian marls without any subsequent overprint. The direction of the magnetic lineation obtained from the AMS at room and low temperatures, agrees with the orientation of the stress axes obtained from the analysis of brittle mesostructures (mainly faults and calcite-filled tension gashes) indicating its tectonic origin. We interpret the orientation of the magnetic ellipsoids related to the transtensional movements linked to the formation of the Organyà basin during the Aptian-Albian interval, which are consistent with the eastward displacement and rotation of Iberia with respect to Europe. Analysis of tension gashes also indicates a main NW-SE extension direction, whereas palaeostress analysis of striated faults shows a more N-S trending ?3. The transtensional model proposed from magnetic fabric and brittle mesostructures for the Organyà basin during the Aptian-Albian is consistent with the creation of a strongly subsiding area south of the Axial Zone during the Cretaceous and implies that rotation and separation of Iberia respect to Europe took place simultaneously.

Oliva-Urcia, B.; Casas, A. M.; Soto, R.; Villalaín, J. J.; Kodama, K.

2011-01-01

376

A transtensional basin model for the Organyà basin (central southern Pyrenees) based on magnetic fabric and brittle structures  

NASA Astrophysics Data System (ADS)

This work deals with anisotropy of the magnetic susceptibility (AMS) and the study of brittle mesostructures of the inverted extensional Organyà basin (Central Southern Pyrenees). Separation of magnetic subfabrics (analyses of AMS at low temperature and anisotropy of the anhysteretic remanence -AARM-) has been also done to properly interpret the obtained AMS data. The combination of all magnetic fabric analyses and brittle mesostructures has provided new information to clarify the structural evolution of the basin, which support a new tectonic model for the Aptian-Albian basinal stage. Twenty sites for the magnetic fabric analysis were sampled in Aptian-Lower Albian marls. The AMS ellipsoids obtained at room temperature show their kmax axes oriented NW-SE in 70% of the samples, N-S in 15% and NE-SW in 15%. Analyses of AMS at low temperature show a better clustering of the axes of the magnetic ellipsoid pointing out that phyllosilicates constitute the carriers of the AMS, whereas the analyses of the AARM confirm the scattering of the ferromagnetic grains. These results suggest that the obtained AMS in the Organyà basin was acquired during or shortly after deposition of the Aptian-Lower Albian marls without any subsequent overprint. The direction of the magnetic lineation obtained from the AMS at room and low temperatures, agrees with the orientation of the stress field obtained from the analysis of brittle mesostructures (mainly faults and calcite-filled tension gashes) indicating its tectonic origin. We interpret the orientation of the magnetic ellipsoids related to the transtensional movements linked to the formation of the Organyà basin during the Aptian-Albian interval, which are consistent with the eastward displacement and rotation of Iberia with respect to Europe. Analysis of tension gashes also indicates a main NW-SE extension direction, whereas paleostress analysis of striated faults shows a more N-S trending ?3. The transtensional model proposed from AMS and brittle mesostructures for the Organyà basin during the Aptian-Albian is consistent with the creation of a strongly subsiding area south of the Axial Zone during the Cretaceous.

Oliva-Urcia, B.; Casas, A. M.; Soto, R.; Villalain, J.; Kodama, K.

2010-12-01

377

The Castle Mountain fault, south-central Alaska: New lidar-based observations on the sense of slip  

NASA Astrophysics Data System (ADS)

The Castle Mountain fault extends along the southern Talkeetna Mountains rangefront and across the Susitna Lowland in south-central Alaska. The fault is an active structural element of the Aleutian forearc and has formed a 4-km-wide anticline associated with at least 0.5 km of north-side-up displacement. Right-lateral bedrock offsets along the eastern part of the fault are poorly constrained to ~14 km. In the Susitna Lowland, the fault is expressed at the surface by a distinct south-facing scarp. Previous paleoseismic studies have described the fault as both a strike-slip fault and a reverse fault, attributed the scarp to the occurrence of one to four paleoearthquakes, and estimated a Holocene right-lateral slip rate of ~3mm/yr. Motivated by inspection of new lidar data along the fault indicating that Holocene landforms are not laterally offset, we performed surficial-geologic mapping and field surveys with an emphasis on better characterizing the sense of slip. Field work was conducted along approximately 12 km of the scarp between Houston and Susitna River. Surficial-geologic mapping indicates that the fault displaces late Elmendorf (14-15 ka) glacial and Holocene deposits including glacial drift, sandy fan deltas, outwash plains, grounding-line moraines, basal-crevasse-fill complexes, stream terraces, oxbow lakes, and swamps. Where the scarp cuts these deposits it varies in height from ~ 0.5-4 m and is un-beveled. The surface trace also consists of left-stepping en echelon scarps and grabens. The grabens occur up to 400 m north of the scarp and indicate a wide zone of deformation. Numerous abandoned channels and stabilized sand dunes oriented orthogonal to the scarp are vertically offset and have negligible strike-slip displacement. The observations are consistent with reverse faulting above a north dipping fault associated with bending moment extensional grabens in the hanging wall. The en echelon pattern of scarps suggests a minor oblique component of slip. We suggest that the lateral slip rate presently used in probabilistic seismic hazard assessments (3 mm/yr) may be incorrect and that the fault may be better characterized as a reverse fault.

Koehler, R. D.; Reger, D.; Frohman, R. A.

2012-12-01

378

IPO Central  

NSDL National Science Digital Library

IPO (Initial Public Offerings) Central, provided by The Reference Press, contains a wealth of information on IPOs. It features a complete list of companies that "filed for an initial public offering of common stock on or after May 6, 1996, the first day that all US companies were required to file electronically," along with EDGAR Online SEC filings. This directory can be accessed alphabetically or by date, and the latest filings are available under a separate menu item. IPO Central also highlights one featured IPO per week, with a free link to a Hoover Online profile on that company. "The Insider" offers short analytical columns on IPOs, and the "Beginner's Guide" has links to basic IPO information to help the novice. The site also offers links to other IPO-related sites. IPO Central does not at this time offer a searchable interface to its directory, but the providers promise improved search features soon. Note that listings are removed from the directory after six months and that EDGAR Online is in no way related to SEC (Securities and Exchange Commission) EDGAR.

379

High Resolution Remote Sensing based Quantification of the Remnant Vegetation Cover in the Araguaia River Basin, Central Brazil  

Microsoft Academic Search

The Araguaia\\/Tocantins watershed, with 380,000 km2 drainage basin towards the north portion of Brazil, is one of the major fluvial and phyto-physiognomic system in South America. Its headwaters are situated in the southern portion of the Brazilian savannas (locally known as Cerrado biome), considered one of the world's biodiversity hotspot. Based on 2006 high spatial resolution CCD imagery (20m) of

Manuel Eduardo Ferreira; Laerte Guimarães Ferreira; Edgardo Manuel Latrubesse; Fausto Miziara

2008-01-01

380

Difference in capacity between macrophages and dendritic cells from rat incisor pulp to provide accessory signals to concanavalin-A-stimulated T-lymphocytes.  

PubMed

The present study compared the ability of dendritic cells and macrophages derived from the dental pulp to provide accessory signals to Concanavalin A (Con A)-stimulated T-lymphocytes. Pulpal cells from maxillary and mandibular rat incisors were enzymatically released with collagenase. T-lymphocytes were isolated from rat cervical lymph nodes. In initial experiments, suspensions of unseparated pulpal cells were found to provide co-stimulatory help to Con-A-treated T-lymphocytes. The proliferation rate correlated well with the number of cells in the pulp suspension and followed a time course characteristic of a Con-A-driven proliferation of T-lymphocytes. Depletion of class II molecule-expressing cells from the unpurified suspension of pulpal cells resulted in lost ability to provide accessory signals to Con-A-stimulated T-lymphocytes. In contrast, removal of ED2-positive cells, i.e., macrophages, did not affect the ability of the suspension to give this assistance. Partially purified class II molecule-expressing cells enhanced the proliferative response, while addition of enriched macrophages did not. It was concluded that cells in the normal dental pulp with the characteristics of dendritic cells have the capacity to provide help to Con-A-stimulated T-lymphocytes, while cells with the macrophage phenotype lack this ability. PMID:8006232

Jontell, M; Eklöf, C; Dahlgren, U I; Bergenholtz, G

1994-05-01

381

Comparative evaluation of ceramic bracket base designs.  

PubMed

Since the initial introduction of ceramic brackets, base designs have been modified to reduce tooth damage during debonding. The purpose of this study was to compare shear and tensile bond strengths and fracture sites of four second-generation ceramic brackets: Allure IV (A) (GAC International, Inc., Central Islip, N.Y.), Ceramaflex (C) (TP Orthodontics, Inc., LaPorte, Ind.), Intrigue (I) (Lancer Orthodontics, Carlsbad, Calif.), Transcend 2000 (T) (Unitek Corp., Monrovia, Calif.), and a foil-mesh base stainless steel bracket, DynaBond II (D) (Unitek Corp., Monrovia, Calif.). Twenty brackets of each type were bonded to 100 mandibular bovine incisor teeth with Concise bonding adhesive. The samples were thermocycled for 24 hours and the brackets were debonded with an Instron universal testing machine (Instron Corp., Canton, Mass.). A modified Transcend debonding instrument was used for tensile debonding, whereas a chisel was used for shear debonding. An analysis of variance was performed with a 0.05 level of confidence. Mean shear strengths (kg/cm2) necessary to debond were 174.0 (A), 71.0 (C), 189.0 (I), 228.0 (T), and 160.0 (D). Mean tensile strengths (kg/cm2) were 27.0 (A), 26.7 (C), 51.3 (I), 56.5 (T), and 48.6 (D). Fracture sites examined with a light microscope showed no enamel damage with any of the ceramic brackets. Intrigue was the only bracket to fracture and had 30% bracket fracture in the tensile mode and 20% bracket fracture in the shear mode. The percentage of fractures at the adhesive-bracket base interface for shear and tensile modes, respectively, were 80, 100 (A); 100, 90 (C); 10, 60 (I); 60, 90 (T); and 90, 80 (D).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8198079

Bordeaux, J M; Moore, R N; Bagby, M D

1994-06-01

382

Controls on mineralisation in the Sierra Foothills gold province, central California, USA: A GIS-based reconnaissance prospectivity analysis  

USGS Publications Warehouse

The assessment of spatial relationships between the location, abundance and size of orogenic-gold deposits in the highly endowed Sierra Foothills gold province in California, via the combination of field studies and a GIS-based analysis, illustrates the power of such an approach to the characterisation of important parameters of mineral systems, and the prediction of districts likely to host economic mineralisation. Regional- to deposit-scale reconnaissance mapping suggests that deposition of gold-bearing quartz veins occurred in second- and third-order, east-over-west thrusts during regional east - west compression and right-lateral transpression. At the district-scale, significant zones of mineralisation correspond with such transpressional reactivation zones and dilational jogs that developed during the Late Jurassic - Early Cretaceous along the misaligned segments of first-order faults throughout the Sierra Nevada Foothills Metamorphic Belt. Field-based observations and interpretation of GIS data (including solid geology, structural elements, deposit locations, magnetics, gravity) also highlight the importance of structural permeability contrasts, rheological gradients, and variations in fault orientation for localising mineralisation. Although this approach confirms empirical findings and produces promising results at the province scale, enhanced geological, structural, geophysical and geochronological data density is required to generate regionally consistent, high-quality input layers that improve predictive targeting at the goldfield to deposit-scale.

Bierlein, F.P.; Northover, H.J.; Groves, D.I.; Goldfarb, R.J.; Marsh, E.E.

2008-01-01

383

Early-life gut microbiota under physiological and pathological conditions: the central role of combined meta-omics-based approaches.  

PubMed

The establishment of gut microbiota immediately after birth is modulated by different mechanisms that can be considered specific determinants of temporal and spatial variability. Over the last few years, molecular methods have been offering a complementary support to the classical microbiology, often underpowered by its inability to provide unbiased representation of gut microbiota. The advent of high-throughput-omics-based methods has opened new avenues in the knowledge of the gut ecosystem by shedding light on its shape and modulation. Such methods may unveil taxa distribution, role and density of microbial habitants, hence highlighting individual phenotyping (physiological traits) and their relationship with gut dysbiosis, inflammation processes, metabolic disorders (pathological conditions). Synergic meta-omics or "systems biology"-based approaches may concur in providing advanced information on microbiota establishment and pathogen control. During early-life stages this massive amount of data may provide gut microbiota descriptive and functional charts which can be exploited to perform a good practice in childcare and pediatrics, thus providing nutraceutical benefits and endorsing healthy development and aging. This article is part of a Special Issue entitled: Translational Proteomics. PMID:22387117

Del Chierico, Federica; Vernocchi, Pamela; Bonizzi, Luigi; Carsetti, Rita; Castellazzi, Anna Maria; Dallapiccola, Bruno; de Vos, Willem; Guerzoni, Maria Elisabetta; Manco, Melania; Marseglia, Gian Luigi; Muraca, Maurizio; Roncada, Paola; Salvatori, Guglielmo; Signore, Fabrizio; Urbani, Andrea; Putignani, Lorenza

2012-08-01

384

Analyzing the mid-low porosity sandstone dry frame in central Sichuan based on effective medium theory  

NASA Astrophysics Data System (ADS)

Tight gas sandstone reservoirs in Guang'an are characterized by wide distribution and low abundance. Sandstone samples from this area usually have low porosity and poor connectivity. We analyze the observed velocity data of tight sandstone samples with the Mori-Tanaka model, and give the sandstone framework physical model in this area based on theory and experiment analysis. The matrix modulus was obtained by an empirical relationship and then the experiment data were compared with the values predicted by the Mori-Tanaka model with different pore shapes. The results revealed that the experiment data were close to the model with low pore aspect ratio. Considering the matrix modulus and pore shape variation, we find that, under the condition of small mineral composition change, the effective pore aspect ratio of these samples increased with porosity evidently.

Yan, Xin-Fei; Yao, Feng-Chang; Cao, Hong; Ba, Jing; Hu, Lian-Lian; Yang, Zhi-Fang

2011-09-01

385

iTRAQ-based protein profiling provides insights into the central metabolism changes driving grape berry development and ripening  

PubMed Central

Background Grapevine (Vitis vinifera L.) is an economically important fruit crop. Quality-determining grape components such as sugars, acids, flavors, anthocyanins, tannins, etc., accumulate in the different grape berry development stages. Thus, correlating the proteomic profiles with the biochemical and physiological changes occurring in grape is of paramount importance to advance in our understanding of berry development and ripening processes. Results We report the developmental analysis of Vitis vinifera cv. Muscat Hamburg berries at the protein level from fruit set to full ripening. An iTRAQ-based bottom-up proteomic approach followed by tandem mass spectrometry led to the identification and quantitation of 411 and 630 proteins in the green and ripening phases, respectively. Two key points in development relating to changes in protein level were detected: end of the first growth period (7?mm-to-15?mm) and onset of ripening (15?mm-to-V100, V100-to-110). A functional analysis was performed using the Blast2GO software based on the enrichment of GO terms during berry growth. Conclusions The study of the proteome contributes to decipher the biological processes and metabolic pathways involved in the development and quality traits of fruit and its derived products. These findings lie mainly in metabolism and storage of sugars and malate, energy-related pathways such as respiration, photosynthesis and fermentation, and the synthesis of polyphenolics as major secondary metabolites in grape berry. In addition, some key steps in carbohydrate and malate metabolism have been identified in this study, i.e., PFP-PFK or SuSy-INV switches among others, which may influence the final sugar and acid balance in ripe fruit. In conclusion, some proteins not reported to date have been detected to be deregulated in specific tissues and developmental stages, leading to formulate new hypotheses on the metabolic processes underlying grape berry development. These results open up new lines to decipher the processes controlling grape berry development and ripening. PMID:24152288

2013-01-01

386

Prenatal and Perinatal Morbidity in Children with Tic Disorders: A Mainstream School-based Population Study in Central Spain  

PubMed Central

Background While current research suggests that genetic factors confer the greatest risk for the development of tic disorders, studies of environmental factors are relatively few, with a lack of consistent risk factors across studies. Our aim is to analyze the association of tic disorders with exposure to prenatal and perinatal morbidity. Methods This was a nested case–control study design. Cases and controls were selected and identified from a mainstream, school-based sample. The diagnosis of tic disorders was assigned by a movement disorder neurologist using ‘Diagnostic and statistical manual of mental disorders, 4th edition, text revision’ criteria, and neuropsychiatric comorbidities were screened using the Spanish computerized version of the Diagnostic Interview Schedule for Children Predictive Scale. Information regarding the exposure to pre-perinatal risk factors was collected by a retrospective review of the birth certificates. Logistic regression analyses were then performed to test the association of tic disorders with pre-perinatal risk factors. Results Out of 407 participants, complete pre-perinatal data were available in 153 children (64 with tics and 89 without tics). After adjusting for family history of tics, neonatal respiratory distress syndrome, body mass index, prenatal infection, and coexisting comorbid neuropsychiatric disturbances, tic disorders were associated with prenatal exposure to tobacco (odds ratio [OR]?=?3.07, 95% confidence interval [CI] 1.24–7.60, p?=?0.007), and cesarean section (OR?=?5.78, 95% CI 1.60–20.91, p?=?0.01). Discussion This nested case–control study of children with tic disorders demonstrates higher adjusted odds for tics in children with exposure to cesarean delivery and maternal smoking. Longitudinal, population-based samples are required to confirm these results. PMID:25562036

Cubo, Esther; Hortigüela, Montesclaros; Jorge-Roldan, Sandra; Ciciliani, Selva Esther; Lopez, Patricia; Velasco, Leticia; Sastre, Emilio; Ausin, Vanesa; Delgado, Vanesa; Saez, Sara; Gabriel-Galán, José Trejo; Macarrón, Jesús

2014-01-01

387

Sonnet Central  

NSDL National Science Digital Library

Created by a dedicated sonnet aficionado, Sonnet Central is not intended for the scholar, per se, but for the reader, the Internaut with a weakness for poetry. The site contains a collection of English-language sonnets, grouped by period and region or by author, and modernized for contemporary readers. Pictures, contemporaneous critical works, a bibliography, and audio files of readings of selected poems complement the sonnets, some of which are maintained off-site (many at the University of Toronto). From Shakespeare to Wilfred Owen, selections from many well-known sonneteers are here alongside those of their less famous contemporaries.

388

Neuropsychology Central  

NSDL National Science Digital Library

Neuropsychology Central is devoted to the subject of - "Neuropsychology, a new branch of science with the specific and unique aim of investigating the role of individual brain systems in complex forms of mental activity." - A.R. Luria "The Working Brain" The page aims to describe the importance of neuropsychology as a science of brain and behavior, and to act as a resource for the professional and layperson alike. See links to current technology for brain imaging, and sections covering different aspects of this ever growing field such as cognitive, developmental, and geriatric Neuropsychology. In addition, a reader survey is included to facilitate the expansion of the site.

Browndyke, J. N.

389

Prevalence of Hypertension and Associated Factors in an Indigenous Community of Central Brazil: A Population-Based Study  

PubMed Central

Objective The aim of the present study was to assess the prevalence of hypertension and cardiovascular risk factors among the native indigenous of Jaguapiru village in Dourados, Mato Grosso do Sul, Brazil. Method A cross-sectional, population-based study was conducted with adult indigenous aged 18 years or more. The subjects' blood pressure was measured twice, and the mean of the two measurements was calculated. Body weight, height, capillary blood glucose and waist circumference were measured. Pregnant women, individuals using glucocorticoids, and non-indigenous villagers and their offspring were excluded. Multivariate regression analyses were conducted on the socio-demographic and clinical independent variables. Interactions between independent variables were also tested. Results We included 1,608 native indigenous eligible to the research. The prevalence of hypertension was 29.5% (95% CI: 27–31.5), with no significant difference between the genders. For both men and women, diastolic hypertension was more common than systolic hypertension. The prevalence of hypertension was higher among obese, diabetic, and older participants, as well as those who consumed alcohol, had a lower educational level, or had a family history of hypertension. There was no association between hypertension and tobacco smoking or family income. Conclusion Hypertension among the indigenous from Jaguapiru village was similar to the prevalence in the Brazilians, but may have a more negative effect in such disadvantaged population. The associated factors we found can help drawing prevention policies. PMID:24489710

Oliveira, Geraldo F.; Oliveira, Teresinha R. R.; Ikejiri, Adauto T.; Andraus, Mariela P.; Galvao, Tais F.; Silva, Marcus T.; Pereira, Maurício G.

2014-01-01

390

Changes of glacial lakes and implications in Tian Shan, central Asia, based on remote sensing data from 1990 to 2010  

NASA Astrophysics Data System (ADS)

Changes of glacial lakes and implications were assessed for the Tian Shan Mountains from 1990 to 2010, based on Landsat Thematic Mapper/Enhanced Thematic Mapper Plus images. The total area of glacial lakes has expanded greatly over the last 20 years, at an average rate of 0.69 ± 0.12 km2 a-1 or 0.8 ± 0.1% a-1. Eastern Tian Shan contributed nearly half that increase (?0.34 ± 0.03 km2 a-1), followed by northern Tian Shan at 0.17 ± 0.03 km2 a-1. Both widespread climate warming and glacier shrinking led to glacial lake areal expansion, while small to medium (<0.6 km2) lakes responded most sensitively to glacier retreat. The closer the hydrologic connection of lakes to glaciers, the greater the areal expansion rate. An average ?0.007 ± 0.002 Gt a-1 of glacier meltwater has been temporarily held in lakes over the past two decades. The increasing quantity of melt available for lake formation and growth may simultaneously increase the frequency and damage of glacial lake outburst floods or debris flows in this region. Sixty potentially dangerous glacial lakes are identified, among which 12 have an outburst probability status of ‘high’, 25 ‘medium’ and 23 ‘low’.

Wang, Xin; Ding, Yongjian; Liu, Shiyin; Jiang, Lianghong; Wu, Kunpeng; Jiang, Zongli; Guo, Wanqin

2013-12-01

391

Sarcoma: concordance between initial diagnosis and centralized expert review in a population-based study within three European regions  

PubMed Central

Background Sarcomas represent a heterogeneous group of tumors. Accurate determination of histological diagnosis and prognostic factors is critical for the delineation of treatment strategies. The contribution of second opinion (SO) to improve diagnostic accuracy has been suggested for sarcoma but has never been established in population-based studies. Methods Histological data of patients diagnosed with sarcoma in Rhone-Alpes (France), Veneto (Italy) and Aquitaine (France) over a 2-year period were collected. Initial diagnoses were systematically compared with SO from regional and national experts. Results Of 2016 selected patients, 1463 (73%) matched the inclusion criteria and were analyzed. Full concordance between primary diagnosis and SO (the first pathologist and the expert reached identical conclusions) was observed in 824 (56%) cases, partial concordance (identical diagnosis of connective tumor but different grade or histological subtype) in 518 (35%) cases and complete discordance (benign versus malignant, different histological type or invalidation of the diagnosis of sarcoma) in 121 (8%) cases. The major discrepancies were related to histological grade (n = 274, 43%), histological type (n = 144, 24%), subtype (n = 18, 3%) and grade plus subtype or grade plus histological type (n = 178, 29%). Conclusion More than 40% of first histological diagnoses were modified at second reading, possibly resulting in different treatment decisions. PMID:22331640

Ray-Coquard, I.; Montesco, M. C.; Coindre, J. M.; Dei Tos, A. P.; Lurkin, A.; Ranchère-Vince, D.; Vecchiato, A.; Decouvelaere, A. V.; Mathoulin-Pélissier, S.; Albert, S.; Cousin, P.; Cellier, D.; Toffolatti, L.; Rossi, C. R.; Blay, J. Y.

2012-01-01

392

Landslide Hazard Mapping Using Ground-based Interferometric Radar in the Fjords of South-Central Alaska  

NASA Astrophysics Data System (ADS)

The cities of Seward and Whittier, Alaska are situated at the base of steep walls within two fjords located on the Kenai Peninsula. Historic events have shown that the combination of terrain, geology, and vegetation are factors which can lead to significant events of erosion in the surrounding slopes during periods of heavy rainfall. While other remote sensing techniques have been shown to be useful for accessing landslide hazards, local surface processes may be better understood to create more accurate hazard maps and predictive models by using data gained from interferometric radar. To gain perspective into where, and at which speed, slopes are deforming, we utilize the GPRI-2 terrestrial interferometric radar system which transmits signals in the Ku band. The GPRI-2 portable radar unit has several advantages to space-borne radar, including relative freedom of site selection and regions to target, ability to determine temporal baselines, and repeat acquisitions which can be collected with a zero spatial-baseline. There are however, problems which need to be addressed when using such a system in the fjord environments, and in particular for monitoring slope deformation in these areas. Foremost, the noise that is attributed to the atmosphere is of great concern as it is sometimes required to position the radar several kilometers away from the target, across open water. We offer our results of correcting for this interference and report the results. Secondly, we address the issue of repeat acquisitions over long periods of time, which is needed to detect movements in the slope, and report on the decorrelation of the signal in the various land cover types in the study areas. Finally, we offer suggestions of the usefulness of such a system to detect slope deformation in similar environments.

Balazs, M. S.; Meyer, F. J.; Bollian, T.; Wolken, G. J.; Prakash, A.

2013-12-01

393