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Sample records for comparative histomorphometric study

  1. Comparative histomorphometric study of bone tissue synthesized after electric and ultrasound stimulation.

    PubMed

    Coman, Mălina; Hîncu, Mihaela; Surlin, Petra; Mateescu, Garofiţa; Nechita, A; Banu, Mihaela

    2011-01-01

    The clinical use of the alternative therapies in traumatology is conditioned by the knowledge and understanding of their actions on the bone tissue. The hereby study aims at the comparative assessment of the effectiveness of the direct current and ultrasounds in treating the fractures. Thus, we have proceeded to a comparative histological study of the bone tissue in the fractured area and the biomechanical description and the three-dimensional model of the stimulated bone's behavior by using micro-CT X-rays and the finite element analysis. The findings clearly show that the bone, which has been stimulated during a period of two weeks, has regained its functions, that is 85% of the compression one and 95% of the shearing one. These values prove that 90% of the bone structure has healed.

  2. Comparative histomorphometrical study of genital tract in adult laying hen and duck.

    PubMed

    Mohammadpour, Ahmad-Ali; Zamanimoghadam, Abdolkarim; Heidari, Massoumeh

    2012-01-01

    This study was carried out to compare the histomorphological structures of oviductal regions of the apparently healthy adult laying hens (Gallus gallus dometicus) and ducks (Ansa ansa domesticus). For this purpose, 20 hens and 20 female ducks aged between 1-1.5 years were used. After euthanasia, the oviducts were dissected out and all of the gross morphometrical parameters including length, width and thickness as well as weight and length of them were recorded. For histological studies, after tissue preparation and staining with H&E, histological layers of isthmus, uterus and vagina were recognized and the size of them with micrometry method were determined. Our data analyses indicated that, the mean weight, length of oviduct as well as weight of isthmus, uterus in hen were significantly (P < 0.05) greater than that of duck, whereas the vaginal thickness and weight were greater in duck than the hen. In histological studies, epithelium and cilia were well developed in duck and lamina propria was filled with glands in the regions of the isthmus and uterus. The length of primary mucosal folds of isthmus and uterus in duck was more than hen. The longest mucosal fold has been seen in uterus. Most of the parameters in duck were greater than hen except the length of secondary fold of three parts of oviduct including isthmus, uterus, and vagina.

  3. Electromagnetic stimulation of bone repair: a histomorphometric study.

    PubMed

    Canè, V; Botti, P; Farneti, D; Soana, S

    1991-11-01

    The effect of pulsing electromagnetic fields (PEMFs) on bone repair was studied in principal metacarpal bones of eight adult male horses: Six horses were treated with PEMFs, and two horses were untreated. In treated horses, Helmholtz coils were applied during a 60-day period to the left metacarpal bones, bored with eight holes of equal diameter and depth, from the middiaphysis toward the distal metaphysis. Eight equal holes bored in the right metacarpal, surrounded by unactivated Helmholtz coils, were taken as controls. The two untreated horses were taken as additional control. The results of computer-assisted histomorphometric analysis indicate that (a) in diaphyseal levels, the amount of bone formed during 60 days is significantly greater (p less than 0.01) in PEMF-treated holes than in contralateral ones and those in control horses; (b) in metaphyseal levels, PEMF-treated holes are sometimes more closed, sometimes less, as compared with contralateral holes and those in control horses; in any case the statistical analysis indicates that the symmetry in the rate of hole repair, found between the two antimeres of control horses, is not appreciable at metaphyseal levels also; (c) there was no statistically significant difference between untreated holes in PEMF-treated horses and holes in control horses, neither at diaphyseal nor at metaphyseal levels. These preliminary findings indicate that PEMFs at low frequency influence the process of bone repair on both diaphysis and metaphysis, and seem to improve the process of bone repair in skeletal regions normally having a lower osteogenetic activity, i.e., in diaphyses as against metaphyses.

  4. Chondroclasts in fusarium-induced tibial dyschondroplasia. A histomorphometric study.

    PubMed Central

    Lawler, E. M.; Fletcher, T. F.; Walser, M. M.

    1985-01-01

    The role of chondroclasts in the pathogenesis of Fusarium roseum-induced tibial dyschondroplasia (TD) was examined in a histomorphometric study. TD developed rapidly in broiler chickens placed at 1 day of age on rations containing either 3% (Experiment 1) or 2% (Experiment 2) F roseum cultures. In Experiment 1 the frequency of TD in birds killed at 4 weeks of age was 90%. In Experiment 2, birds were killed at intervals from 4 days until 4 weeks of age. By 1 week of age, 70% of birds examined had characteristic accumulations of prehypertrophic cartilage at the proximal tibial physis, and the frequency of TD in 4-week-old birds was 80%. Sections of hypertrophic cartilage from F roseum-fed and control birds from both experiments were examined for determination of the volume density of chondroclasts along the vascular channel boundary. Chondroclast density was consistently lower in F roseum-fed than in control birds, but the difference was significant only at 4 weeks of age. The fact that gross lesions were evident before a significant decrease in chondroclast density occurred indicates that a decrease in the density of chondroclasts was not an essential factor in the accumulation of cartilage characteristic of TD. Images Figure 1 Figure 2 PMID:4025512

  5. The Role of Skeletal Muscle in External Ear Development: A Mouse Model Histomorphometric Study

    PubMed Central

    Rot, Irena

    2015-01-01

    Background: Mechanical stimuli imparted by skeletal muscles play an important role during embryonic development in vertebrates. Little is known whether skeletal muscles are required for normal external ear development. Methods: We used Myf5−/−:MyoD−/− (double-mutant) mouse embryos that completely lack skeletal musculature and analyzed the development of the external ear. We concentrated on the external ear because several studies have suggested a muscular cause to various congenital auricular deformities, and middle and inner ear development was previously reported using the same mouse model. Wild-type mouse embryos were used as controls to compare the histomorphometric outcomes. Results: Our findings demonstrated an absence of the external auditory meatus, along with an abnormal auricular appearance, in the double-mutant mouse embryos. Specifically, the auricle did not protrude laterally as noted in the wild-type mouse ears. However, histomorphometric measurements were not significantly different between the wild-type and double-mutant mouse ears. Conclusion: Overall, our study showed that the development of the mouse external ear is dependent on the presence of skeletal muscles. PMID:26090272

  6. Defective bone microstructure in hydronephrotic mice: a histomorphometric study in ICR/Mlac-hydro mice.

    PubMed

    Suntornsaratoon, Panan; Wongdee, Kannikar; Tiyasatkulkovit, Wacharaporn; Ampawong, Sumate; Krishnamra, Nateetip; Kengkoom, Kanchana; Charoenphandhu, Narattaphol

    2014-02-01

    Chronic renal impairment can lead to bone deterioration and abnormal bone morphology, but whether hydronephrosis is associated with bone loss remains unclear. Herein, we aimed to use computer-assisted bone histomorphometric technique to investigate microstructural bone changes in Imprinting Control Region (ICR) mice with a spontaneous mutation that was associated with bilateral nonobstructive hydronephrosis (ICR/Mlac-hydro). The results showed that 8-week-old ICR/Mlac-hydro mice manifested decreases in trabecular bone number and thickness, and an increased trabecular separation, thereby leading to a reduction in trabecular bone volume compared with the wild-type mice. Furthermore, histomorphometric parameters related to both bone resorption and formation, that is, eroded surface, osteoclast surface, and osteoblast surface, were much lower in ICR/Mlac-hydro mice than in the wild type. A decrease in moment of inertia was found in ICR/Mlac-hydro mice, indicating a decrease in bone strength. In conclusion, ICR/Mlac-hydro mice exhibited trabecular bone loss, presumably caused by marked decreases in both osteoblast and osteoclast activities, which together reflected abnormally low bone turnover. Thus, this mouse strain appeared to be a valuable model for studying the hydronephrosis-associated bone disease.

  7. Comparative assessment of bone mass and structure using texture-based and histomorphometric analyses

    PubMed Central

    Xiang, Yongqing; Yingling, Vanessa R.; Malique, Rumena; Li, Chao Yang; Schaffler, Mitchell B.; Raphan, Theodore

    2013-01-01

    The purpose of this study was to develop a methodology for quantitatively assessing bone quantity and anisotropy based on texture analysis using Gabor wavelets. The wavelet approach has the capability to simultaneously examine the images at low and high resolutions to gain information on both global and detailed local features of the bone image. The program that implemented the texture analysis gave measures of density (MDensity) and anisotropy (MAnisotropy). It also allowed us to examine the texture energy at four orientations (0°, 45°, 90°, 135°) to gain insight about the details of the anisotropy. Analysis of templates of four simulated patterns, which had same number of dots but with differing orientations, demonstrated how the texture-based analysis differentiated between these templates. The measures of MAnisotropy discriminated between the four simulated patterns. The MDensity measures were similar across all patterns. These outcomes matched the design intent of the simulated patterns. We also compared the trabecular bone images obtained from a previous study, in which the right forelimbs of normal female retired breeder beagle dogs (5–7 years old) were cast for 12 months to induce bone loss, using both histomorphometry and texture analysis. Both histomorphometry and the texture analysis detected significant differences in the trabecular bone of the distal metatarsal between the control and disuse groups. Percent trabecular bone (Tb.Ar/T.Ar) and the textural density parameter (MDensity) were highly correlated (r =0.962). MAnisotropy was decreased (3.9%) after the 12-month disuse protocol, but was not significantly different from normal. However, the texture energy values at all orientations (0°, 45°, 90° and 135°) were significantly decreased in the disuse group. Therefore, texture analysis was able to assess anisotropy, which could not be extracted from histomorphometric parameters. We conclude that texture analysis is an effective tool for

  8. Histomorphometric study of tibia of rats exposed aboard American Spacelab Life Sciences 2 Shuttle Mission

    NASA Technical Reports Server (NTRS)

    Durnova, G.; Kaplansky, A.; Morey-Holton, E.

    1996-01-01

    Tibial bones of rats flown onboard the SLS-2 shuttle mission were studied. Trabecular bone parameters were investigated, including growth plate height, trabecular bone volume, thickness and number, and trabecular separation in the primary and secondary spongiosa. Several histomorphometric changes were noted, allowing researchers to conclude that exposure to microgravity resulted in osteopenia of spongy bone of tibial metaphysis. The roles of bone formation and bone resorption are discussed.

  9. Nano-crystalline diamond-coated titanium dental implants - a histomorphometric study in adult domestic pigs.

    PubMed

    Metzler, Philipp; von Wilmowsky, Cornelius; Stadlinger, Bernd; Zemann, Wolfgang; Schlegel, Karl Andreas; Rosiwal, Stephan; Rupprecht, Stephan

    2013-09-01

    Promising biomaterial characteristics of diamond-coatings in biomedicine have been described in the literature. However, there is a lack of knowledge about implant osseointegration of this surface modification compared to the currently used sandblasted acid-etched Ti-Al6-V4 implants. The aim of this study was to investigate the osseointegration of microwave plasma-chemical-vapour deposition (MWP-CVD) diamond-coated Ti-Al6-V4 dental implants after healing periods of 2 and 5 months. Twenty-four MWP-CVD diamond-coated and 24 un-coated dental titanium-alloy implants (Ankylos(®)) were placed in the frontal skull of eight adult domestic pigs. To evaluate the effects of the nano-structured surfaces on bone formation, a histomorphometric analysis was performed after 2 and 5 months of implant healing. Histomorphometry analysed the bone-to-implant contact (BIC). No significant difference in BIC for the diamond-coated implants in comparison to reference implants could be observed for both healing periods. Scanning electron microscopy revealed an adequate interface between the bone and the diamond surface. No delamination or particle-dissociation due to shearing forces could be detected. In this study, diamond-coated dental titanium-alloy implants and sandblasted acid-etched implants showed a comparable degree of osseointegration.

  10. A histomorphometric study of necrotic femoral head in rabbits treated with extracorporeal shock waves

    PubMed Central

    Ma, Huan-Zhi; Zhou, Dong-Sheng; Li, Dong; Zhang, Wei; Zeng, Bing-Fang

    2017-01-01

    [Purpose] This study aimed to determine the effectiveness and mechanisms of extracorporeal shock wave therapy in the treatment of femoral head osteonecrosis. [Subjects and Methods] Histomorphometric analysis of necrotic femoral head in rabbits treated with shock waves was performed. Bilateral osteonecrosis of femoral heads was induced with methylprednisolone and lipopolysaccharide in eight rabbits. The left limb (study side) received shock waves to the femoral head. The right limb (control side) received no shock waves. Biopsies of the femoral heads were performed at 12 weeks after shock wave therapy. [Results] Necrotic femoral heads treated with shock waves, compared with controls, had higher bone volume per tissue volume, trabecular thickness, trabecular number, osteoblast surface/bone surface, osteoid surface/bone surface, osteoid thickness, mineralizing surface/bone surface, mineralizing apposition rate, and bone formation rate. However, trabecular separation was lower in shock wave-treated femoral heads than in controls. Eroded surface/bone surface and osteoclast surface/bone surface did not differ significantly between groups. [Conclusion] The bone mass of necrotic femoral heads treated with shock waves increases. Extracorporeal shock wave may promote bone repair in necrotic femoral heads through the proliferation and activation of osteoblasts. PMID:28210032

  11. Influence of direct laser fabrication implant topography on type IV bone: a histomorphometric study in humans.

    PubMed

    Shibli, Jamil Awad; Mangano, Carlo; D'avila, Susana; Piattelli, Adriano; Pecora, Gabriele E; Mangano, Francesco; Onuma, Tatiana; Cardoso, Luciana A; Ferrari, Daniel Sanchez; Aguiar, Kelly C; Iezzi, Giovanna

    2010-05-01

    The aim of this histologic study was to evaluate the influence of the direct laser fabrication (DFL) surface topography on bone-to-implant contact (BIC%), on bone density in the threaded area (BA%) as well as bone density outside the threaded area (BD%) in type IV bone after 8 weeks of unloaded healing. Thirty patients (mean age 51.34 +/- 3.06 years) received 1 micro-implant (2.5-mm diameter and 6-mm length) each during conventional implant surgery in the posterior maxilla. Thirty micro-implants with three topographies were evaluated: 10 machined (cpTi); 10 sandblasted and acid etched surface (SAE) and 10 DFL micro-implants. After 8 weeks, the micro-implants and the surrounding tissue were removed and prepared for histomorphometric analysis. Four micro-implants (2 cpTi, 1 SAE and 1DLF) showed no osseointegration after the healing period. Histometric evaluation indicated that the mean BIC% was higher for the DFL and SAE surfaces (p = 0.0002). The BA% was higher for the DFL surface, although there was no difference with the SAE surface. The BD% was similar for all topographies (p > 0.05). Data suggest that the DFL and SAE surfaces presented a higher bone-to-implant contact rate compared with cpTi surfaces under unloaded conditions, after a healing period of 8 weeks.

  12. Effects of Hypericum perforatum on the healing of xenografts: a histomorphometric study in rabbits.

    PubMed

    Damlar, I; Arpağ, O F; Tatli, U; Altan, A

    2016-12-19

    The aim of this study was to investigate effects of the Hypericum perforatum (St John's Wort) on bone healing in rabbit calvarium. Ten male New Zealand rabbits each had three bicortical defects made in the calvarial bones, which were filled with xenograft, xenograft+H perforatum oil extract, and autogenous graft. Four weeks postoperatively all rabbits were killed and the bony defects examined histomorphometrically. Tissue compartments including new bone (p<0.001), marrow space (p<0.001), and residual bone grafts (p=0.014) differed significantly among groups (p=0.00?). The volume of residual graft was significantly decreased in the xenograft/H perforatum group compared with those with xenografts alone (p=0.0147). The differences in microarchitectural variables of de novo bone formation were also significant (trabecular thickness (p<0.001), trabecular width (p<0.001), trabecular separation (p=0.001). There were no significant differences in node:terminus ratio between the xenograft/H perforatum group and the other two groups. However, the difference in node:terminus ratio between the autogenous graft and xenograft group was significant (p=0.001) Oil extracts of H perforatum improved bony healing in defects filled with bovine-derived xenografts.

  13. Histomorphometric study of the goat stomach during prenatal development.

    PubMed

    Garcia, Angela; Rodriguez, Pedro; Masot, Javier; Franco, Antonio; Redondo, Eloy

    2014-11-01

    The aim of this study was to perform a morphometric analysis of the different structural tissue layers of the goat stomach to study their prenatal growth from mathematical models fitted to these morphometric data. A total of 90 embryos and fetuses were used, from the early stages of prenatal life until birth. The growth rate of the gastric wall was slower than that of body length; rumen was the stomach compartment displaying slowest growth. In the three non-glandular compartments, the epithelial layer grew faster than the gastric wall itself, while the growth rate of the abomasal epithelium declined in the early stages of development. A decline in growth rate was also observed for the lamina propria and submucosa in rumen and reticulum from the early embryonic stages, whereas in omasum and abomasum these layers continued to grow as gestation progressed. The tunica muscularis displayed consistent growth in all compartments, growing faster than the gastric wall. Serosa thickness increased as gestation progressed, displaying a decline in growth-rate only in the omasum. In conclusion, the dynamics of gastric wall growth were governed by the growth rate of each of the component tissue layers.

  14. Histological and histomorphometric study using an ultrasonic crestal sinus grafting procedure. A multicenter case study

    PubMed Central

    Wainwright, Marcel; Pérez-Dorao, Beatriz; Serrera-Figallo, María-Angeles; Gutierrez-Perez, José-Luis; Troedhan, Angelo; Kurrek, Andreas

    2016-01-01

    Background The aim of this study was to evaluate the efficacy of a hydrodynamic ultrasonic driven transcrestal sinus grafting procedure (Intralift ®, Acteon Company, Bordeaux, France) and the use of a bovine high temperature sintered grafting material in sinus sites with less than 5 mm remaining bone height with no additional autogenous bone in order to create a sufficient recipient site for implants. Material and Methods 12 patients (16 sinus) in this multicenter case study were included. Using a crestal approach, bone under the sinus was prepared with ultrasonic tips until the Schneiderian membrane was reached. With a trumpet shaped instrument, the Schneiderian membrane was elevated. In the new created subantral space a high temperature sintered bovine grafting material was introduced (Bego Oss, BEGO Implant Systems GmbH & Co. KG, Bremen, Germany). After 6 months biopsies were taken with a trephine bur and histologies were generated following histomorphometric analysis. Results The results showed new vital bone in average of 33.4% ± 17.05%, and 43.6% ± 16.70 of bone substitute material. No signs of abnormal inflammation were observed. Conclusions This procedure (Intralift ®) allows, using a bovine material with no additional autogenous bone, new bone formation in the sinus in order to allow place implant subantraly. Key words:Bone regeneration, sinus, intralift ®, xenogenic bone graft PMID:26946203

  15. Maxillary Sinus Augmentation Combining Bio-Oss with the Bone Marrow Aspirate Concentrate: A Histomorphometric Study in Humans

    PubMed Central

    Pasquali, Paulo José; Teixeira, Marcelo Lucchesi; de Oliveira, Thiago Altro; de Macedo, Luis Guilherme Scavone; Aloise, Antonio Carlos; Pelegrine, André Antonio

    2015-01-01

    Purpose. To investigate the regenerative results obtained with the association of bone marrow aspirate concentrate using the Bone Marrow Aspirate Concentrate (BMAC) method to a xenogeneic bone graft (Bio-Oss) in sinus floor elevation. Materials and Methods. Using a randomized controlled study design in eight consecutive patients (age of 55.4 ± 9.2 years), 16 sinus floor lift procedures were performed with Bio-Oss alone (control group, CG, n = 8) or combined with bone marrow aspirate concentrate obtained via the BMAC method (test group, TG, n = 8). Six months after the grafting procedures, bone biopsies were harvested during implant placement and were analyzed by histomorphometry. Results. Histomorphometric analysis revealed a significantly higher amount (p < 0.05) of vital mineralized tissue in TG when compared to the CG (55.15 ± 20.91% and 27.30 ± 5.55%, resp.). For nonvital mineralized tissue, TG presented a statistically higher level of Bio-Oss resorption (p < 0.05) when compared with the CG (6.32 ± 12.03% and 22.79 ± 9.60%, resp.). Both groups (TG and CG) showed no significantly different levels (p > 0.05) of nonmineralized tissue (38.53 ± 13.08% and 49.90 ± 7.64%, resp.). Conclusion. The use of bone marrow concentrate obtained by BMAC method increased bone formation in sinus lift procedures. PMID:26543482

  16. Histological and Histomorphometric Human Results of HA-Beta-TCP 30/70 Compared to Three Different Biomaterials in Maxillary Sinus Augmentation at 6 Months: A Preliminary Report

    PubMed Central

    Annibali, Susanna; Iezzi, Giovanna; Sfasciotti, Gian Luca; Cristalli, Maria Paola; Vozza, Iole; Mangano, Carlo; La Monaca, Gerardo; Polimeni, Antonella

    2015-01-01

    Objective. The aim of this investigation was to examine the bone regenerative potential of newly biphasic calcium phosphate ceramics (HA-β-TCP 30/70), by assessing histological and histomorphometric results of human specimens retrieved from sinuses augmented with HA-β-TCP 30/70, and comparing them to anorganic bovine bone (ABB), mineralized solvent-dehydrated bone allograft (MSDBA), and equine bone (EB), after a healing period of 6 months. Materials and Methods. Four consecutive patients with edentulous atrophic posterior maxilla were included in this report. A two-stage procedure was carried out for sinus augmentation with HA-β-TCP 30/70, ABB, MSDBA, and EB. After 6 months, specimens were retrieved at the time of implant placement and processed for histological and histomorphometric analyses. Results. At histological examination, all biomaterials were in close contact with the newly formed bone and showed the same pattern of bone formation; the grafted granules were surrounded by a bridge-like network of newly formed bone. A limited number of ABB particles were partially covered by connective tissue. The histomorphometric analysis revealed 30.2% newly formed bone for Ha-β-TCP 30/70, 20.1% for ABB, 16.4% for MSDBA, and 21.9% for EB. Conclusions. Within the limitations of the present investigation, these results support the successful use of HA-β-TCP 30/70 for sinus augmentation. PMID:26273589

  17. Evaluation of the Biocompatibility of Silicone Gel Implants – Histomorphometric Study

    PubMed Central

    França, Diurianne Caroline Campos; de Castro, Alvimar Lima; Soubhia, Ana Maria Pires; de Aguiar, Sandra Maria Herondina Coelho Ávila

    2013-01-01

    CONFLICT OF INTEREST: NONE DECLARED Breast implants are medical devices that are used to augment breast size or to reconstruct the breast following mastectomy or to correct a congenital abnormality. Breast implants consist of a silicone outer shell and a filler (most commonly silicone gel or saline). Approximately 5 to 10 million women worldwide have breast implants. Histomorphometric study to evaluate the biological tissue compatibility of silicone implants suitable for plastic surgery and the adverse effects and risks of this material. Thirty Wistar white rats received subcutaneous implants and the revestiment of silicone gel Silimed ®®, and randomized into six groups of five animals each, according to the type of implanted material and the time of sacrifice. Eight areas of 60.11mm2 corresponding to the obtained surgical pieces were analyzed, counting mesenchymal cells, eosinophils, and foreign body giant cells, observing an acceptable biocompatibility in all implants, for subsequent statistical analysis by Tukey test. Silicone gel showed inflammation slightly greater than for other groups, with tissue reactions varying from light to moderate, whose result was the formation of a fibrous capsule around the material, recognized by the organism as a foreign body. Despite frequent local complications and adverse outcomes, this research showed that the silicone and top layer presented an acceptable chronic inflammatory reaction, which did not significantly differ from the control group. In general, it is possible to affirm that silicone gel had acceptable levels of biocompatibility, confirmed the rare presence of foreign body giant cells, and when of the rupture, formed a fibrous capsule around the material, separating the material of the organism. PMID:24039333

  18. Synthetic bone substitute material comparable with xenogeneic material for bone tissue regeneration in oral cancer patients: First and preliminary histological, histomorphometrical and clinical results

    PubMed Central

    Ghanaati, Shahram; Barbeck, Mike; Lorenz, Jonas; Stuebinger, Stefan; Seitz, Oliver; Landes, Constantin; Kovács, Adorján F.; Kirkpatrick, Charles J.; Sader, Robert A.

    2013-01-01

    Background: The present study was first to evaluate the material-specific cellular tissue response of patients with head and neck cancer to a nanocrystalline hydroxyapatite bone substitute NanoBone (NB) in comparison with a deproteinized bovine bone matrix Bio-Oss (BO) after implantation into the sinus cavity. Materials and Methods: Eight patients with tumor resection for oral cancer and severely resorbed maxillary bone received materials according to a split mouth design for 6 months. Bone cores were harvested prior to implantation and analyzed histologically and histomorphometrically. Implant survival was followed-up to 2 years after placement. Results: Histologically, NB underwent a higher vascularization and induced significantly more tartrate-resistant acid phosphatase-positive (TRAP-positive) multinucleated giant cells when compared with BO, which induced mainly mononuclear cells. No significant difference was observed in the extent of new bone formation between both groups. The clinical follow-up showed undisturbed healing of all implants in the BO-group, whereas the loss of one implant was observed in the NB-group. Conclusions: Within its limits, the present study showed for the first time that both material classes evaluated, despite their induction of different cellular tissue reactions, may be useful as augmentation materials for dental and maxillofacial surgical applications, particularly in patients who previously had oral cancer. PMID:24205471

  19. Effect of Bacopa Monniera on Cold Stress Induced Neurodegeneration in Hippocampus of Wistar Rats: A Histomorphometric Study

    PubMed Central

    Saraswathi, P; Vijayaraghavan, R

    2015-01-01

    Introduction: Bacopa monniera/ Brahmi,is used over centuries in Ayurvedic medicine for memory development, learning, concentration and other mental illnesses such as nervousness and poor cognition. The present study aims to evaluate the effect of Bacopa monniera (Brahmi, BM) on cold stress induced histological changes in hippocampus of Wistar rats. Materials and Methods: Total 24 male rats divided into four groups were used (n=6) for this study. Group I was control in which rats were kept under ideal laboratory conditions, Group II was given 40 mg/kg of BM extract, Group III was cold water swim stress in which rats were forced to swim in the cold water maintained at 18±2oC till it started to sink for a period of one month and Group IV in which cold water swim stress given for a month followed by oral administration of BM extracts 40mg/kg treatment for a month. The whole study was carried out for a period of 60 d. The animals were sacrificed next day and their brains dissected out for histomorphometric analysis. The diameter, packing density and total number of neurons were calculated from stained histological section by using micrometry in the CA-1 region of the hippocampus. Statistical Analysis: The analysis and plotting of graphs were carried out using Sigma Plot 12 (Systat Software Inc., USA). Values are expressed as Mean ± SEM (n = 6). One way analysis of variance followed by Student-Newman-Keul’s multiple comparisons test was used for the comparison of means. A probability of 0.05 and less was taken as statistically significant. Results: The results showed that there is no significant difference in the diameter of the cells between the groups but total number of the cells in Group II was statistically significant when compared with the others groups. Student–Newman–Keuls method showed that Group II and Group IV are statistically significant when compared to Group III (p<0.05). Conclusion: Results indicates that when BM extracts administered orally

  20. Quantification of Osteon Morphology Using Geometric Histomorphometrics.

    PubMed

    Dillon, Scott; Cunningham, Craig; Felts, Paul

    2016-03-01

    Many histological methods in forensic anthropology utilize combinations of traditional histomorphometric parameters which may not accurately describe the morphology of microstructural features. Here, we report the novel application of a geometric morphometric method suitable when considering structures without anatomically homologous landmarks for the quantification of complete secondary osteon size and morphology. The method is tested for its suitability in the measurement of intact secondary osteons using osteons digitized from transverse femoral diaphyseal sections prepared from two human individuals. The results of methodological testing demonstrate the efficacy of the technique when applied to intact secondary osteons. In providing accurate characterization of micromorphology within the robust mathematical framework of geometric morphometrics, this method may surpass traditional histomorphometric variables currently employed in forensic research and practice. A preliminary study of the intersectional histomorphometric variation within the femoral diaphysis is made using this geometric histomorphometric method to demonstrate its potential.

  1. Effects of Long Term Exposure of 900-1800 MHz Radiation Emitted from 2G Mobile Phone on Mice Hippocampus- A Histomorphometric Study

    PubMed Central

    Shanmugasamy, Kathirvelu; Anbalagan, Jayaram; Rajanarayanan, Swamynathan; Meenachi, Swamynathan

    2016-01-01

    Introduction The advancement in the telecommunications technology with multi-functional added features in mobile phone, attracts more users of all age group. It is alarming to note that, the mobile phone use has increased amongst children and they are exposed to potentially harmful radiofrequency radiation in their lifetime. Aim To investigate the long term exposure of 900 to 1800 MHz radiations emitted from 2G mobile phone in mice hippocampus at histomorphometric level. Materials and Methods With due approval from institutional animal ethics committee, 36 mice were exposed to 2G mobile phone radiation, 48 minutes per day for a period of 30-180 days. The control group was kept under similar conditions without 2G exposure. Mice were sacrificed and the brain was removed from the first month to six months period. Brain was removed from the cranial cavity and hippocampus region was dissected out carefully and processed for routine histological study. Random serial sections were analysed under microscope for histomorphometric changes. For statistical analysis, independent t-test was used for comparing control and 2G exposed groups. Results The mean density of neurons in the hippocampus regions CA1, CA2 and DGDB from first to sixth month was significantly lower in the 2G exposed groups; however, in CA3 and DGVB, the 2G exposed mice showed significantly higher density of neurons. The mean nuclear diameter of neurons in the hippocampus region of CA1, CA2, CA3, DGDB and DGVB from first to sixth months showed lower nuclear diameter in 2G exposed mice. Conclusion The long term exposure to 900-1800 MHz frequency radiations emitted from 2G mobile phone could cause significantly reduced neuron density and decreased nuclear diameter in the hippocampus neurons of mice. PMID:27656427

  2. Histomorphometric assessment of bone necrosis produced by two cryosurgery protocols using liquid nitrogen: an experimental study on rat femurs

    PubMed Central

    COSTA, Fábio Wildson Gurgel; BRITO, Gerly Anne de Castro; PESSOA, Rosana Maria Andrade; STUDART-SOARES, Eduardo Costa

    2011-01-01

    Objective The aim of this study was to evaluate the effects of liquid nitrogen cryosurgery on the femoral diaphysis of rats. Material and Methods The femoral diaphyses of 42 Wistar rats were exposed to three local and sequential applications of liquid nitrogen for 1 or 2 min, intercalated with periods of 5 min of passive thawing. The animals were sacrificed after 1, 2, 4 and 12 weeks and the specimens obtained were processed and analyzed histomorphometrically. Results The depth and extent of peak bone necrosis were 124.509 μm and 2087.094 μm for the 1-min protocol, respectively, and 436.424 μm and 12046.426 μm for the 2-min protocol. Peak necrosis was observed in the second experimental week with both cryotherapy protocols. Conclusions The present results indicate that the 2-min protocol produced more marked bone necrosis than the 1-min protocol. Although our results cannot be entirely extrapolated to clinical practice, they contribute to the understanding of the behavior of bone tissue submitted to different cycles of liquid nitrogen freezing and may serve as a basis for new studies. PMID:22230994

  3. Agarose gel as biomaterial or scaffold for implantation surgery: characterization, histological and histomorphometric study on soft tissue response.

    PubMed

    Varoni, Elena; Tschon, Matilde; Palazzo, Barbara; Nitti, Paola; Martini, Lucia; Rimondini, Lia

    2012-01-01

    Maxillofacial, orthopedic, oral, and plastic surgery require materials for tissue augmentation, guided regeneration, and tissue engineering approaches. In this study, the aim was to develop and characterize a new extrudable hydrogel, based on agarose gel (AG; 1.5% wt) and to evaluate the local effects after subcutaneous implantation in comparison with collagen and hyaluronic acid. AG chemical-physical properties were ascertained through Fourier transform infrared (FT-IR) spectroscopy and rheological analysis. In vivo subcutaneous implants were performed, and histological and histomorphometric evaluations were done at 1, 4, 12, and 16 weeks. FT-IR confirmed that spectroscopic properties were the same for the baseline agarose and rheological characterization established that AG is a weak hydrogel. Subcutaneous AG implants induced new vessels and fibrous tissue formation rich in neutrophils; the capsule thickness around AG increased until the 12th week but remained thinner than those around hyaluronic acid and collagen. At 16 weeks, the thickness of the capsule significantly decreased around all materials. This study confirmed that 1.5% wt AG possesses some of the most important features of the ideal biocompatible material: safety, effectiveness, costless, and easily obtained with specific chemical and geometrical characters; the AG can represent a finely controllable and biodegradable polymeric system for cells and drug delivery applications.

  4. Biomechanical and histomorphometric study of dental implants with different surface characteristics.

    PubMed

    Yeo, In-Sung; Han, Jung-Suk; Yang, Jae-Ho

    2008-11-01

    The aim of this study was to investigate the early bone response to the titanium dental implants with different surface characteristics using the rabbit tibia model. Calcium metaphosphate coated, anodic oxidized, hydroxyapatite particle-blasted, and turned (control) surfaces were compared. Surface topography was evaluated by field emission scanning electron microscope and optical interferometer. Eighteen rabbits received 72 implants in the tibia. Resonance frequency was analyzed every week for 6 weeks. Removal torque values were measured 2 and 6 weeks after placement. The implant-bone interfaces were directly observed by light microscope and bone-to-implant contact ratios were measured 2 and 6 weeks after insertion. All the surface-modified implants showed superior initial bone responses to the control. No significant differences were found among the surface-modified groups. Data suggest that various surface modification methods can provide favorable bone responses for early functioning and healing of dental implants.

  5. Dietary arginine silicate inositol complex increased bone healing: histologic and histomorphometric study

    PubMed Central

    Yaman, Ferhan; Acikan, Izzet; Dundar, Serkan; Simsek, Sercan; Gul, Mehmet; Ozercan, Ibrahim Hanifi; Komorowski, James; Sahin, Kazim

    2016-01-01

    Background Arginine silicate inositol complex (ASI; arginine 49.5%, silicon 8.2%, and inositol 25%) is a novel material that is a bioavailable source of silicon and arginine. ASI offers potential benefits for vascular and bone health. Objective The aim of this study was to evaluate the potential effects of ASI complex on bone healing of critical-sized defects in rats. Methods The rats were randomly assigned to two groups of 21 rats each. The control group was fed a standard diet for 12 weeks; after the first 8 weeks, a calvarial critical-sized defect was created, and the rats were sacrificed 7, 14, and 28 days later. The ASI group was fed a diet containing 1.81 g/kg of ASI for 12 weeks; after the first 8 weeks, a calvarial critical-sized defect was created, and the rats were sacrificed 7, 14, and 28 days later. The calvarial bones of all the rats were then harvested for evaluation. Results Osteoblasts and osteoclasts were detected at higher levels in the ASI group compared with the control group at days 7, 14, and 28 of the calvarial defect (P<0.05). New bone formation was detected at higher levels in the ASI group compared with the controls at day 28 (P<0.05). However, new bone formation was not detected at days 7 and 14 in both the groups (P>0.05). Conclusion ASI supplementation significantly improved bone tissue healing in rats with critical-sized defects. This study demonstrated that ASI can enhance bone repair and has potential as a therapeutic regimen in humans. PMID:27390517

  6. Effects of Two Types of Anorganic Bovine Bone on Bone Regeneration: A Histological and Histomorphometric Study of Rabbit Calvaria

    PubMed Central

    Paknejad, Mojgan; Rokn, Amir Reza; Yaghobee, Siamak; Moradinejad, Pantea; Heidari, Mohadeseh; Mehrfard, Ali

    2014-01-01

    Objective: The purpose of this study was to evaluate the efficacy of two types of bone substitutes, Bio-Oss and NuOss, for repair of bone defects. Materials and Methods: This study was performed on the calvaria of 14 New Zealand rabbits. The 6mm critical size defect (CSD) models of bone regeneration were used. Three CSDs were created in each surgical site. The first defect was filled with NuOss, the second one with Bio-Oss and the third one remained unfilled as the control. After healing periods of one and two months (seven animal for each time point), histological and histomorphometric analyses were carried out to assess the amount of new bone formation, presence of inflammation, foreign body reaction and type of new bone. Qualitative variables were analyzed by multiple comparisons, Wilcoxon, Friedman and Mann Whitney tests. Quantitative variables were analyzed using the Mann-Whitney and Wilcoxon tests. Level of statistical significance was set at 0.05. Results: The level of inflammation was not significantly different at four and eight weeks in the Bio-Oss (P=0.944), NuOss (P=1.000) and control groups (P=0.71). At four weeks, foreign body reaction was not observed in Bio-Oss, NuOss and control groups. There was no significant difference in the type of the newly formed bone at four and eight weeks in any group (P=0.141 for Bio-Oss, P=0.06 for NuOss and P=0.389 for the control group). Conclusion: Deproteinized bovine bone mineral can be used as a scaffold in bone defects to induce bone regeneration. PMID:25628699

  7. Histomorphometric Analysis of Angiogenesis using CD31 Immunomarker and Mast Cell Density in Oral Premalignant and Malignant Lesions: A Pilot Study

    PubMed Central

    Jyothsna, M; Rammanohar, M

    2017-01-01

    Introduction Mast cells have been implicated in promoting angiogenesis in malignant tumors of lung, oesophagus and breast, but there are few studies on Oral Squamous Cell Carcinomas (OSCC). Most oral squamous cell carcinomas arise from pre-existing precancerous lesions exhibiting epithelial dysplasia. Aim The present pilot study attempts to compare Mast Cell Density (MCD), Microvessel Density (MVD), Microvessel Area (MVA) histomorphometrically between normal buccal mucosa, severe epithelial dysplasia and OSCC and to correlate the role of mast cells and angiogenesis in tumor progression. Material and Methods The retrospective study was conducted on eight cases of OSCC, eight cases of severe epithelial dysplasia and five cases of normal buccal mucosa. Immunohistochemical staining with anti CD–31, to demonstrate angiogenesis and toluidine blue staining for mast cells were employed. MVA, MVD and MCD were calculated using the measurement tools of the image analysis software and compared between the groups. One way ANOVA (Analysis of Variance) was used for comparing the parameter for multiple groups followed by Games Howell test. To assess the relationship between micro vessel density and mast cell density, Karl Pearson’s correlation was used. Results MCD and MVD increased with disease progression and were statistically higher in OSCC than in severe epithelial dysplasia and normal buccal mucosa (p<0.001). MVA increased from normal to severe dysplasia and decreased from dysplasia to OSCC, may be due to revascularization of tumor tissue. A positive correlation was observed between MCD and MVD in OSCC and dysplasia, though were not statistically significant. Conclusion These findings suggest that mast cells may up regulate angiogenesis in OSCC. MCD and MVD may be used as indicators for disease progression. PMID:28274041

  8. Histomorphometric Study of Alveolar Bone Healing in Rats Fed a Boron-Deficient Diet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bone healing after tooth extraction in rats is a suitable experimental model to study bone formation. Thus, we performed a study to determine the effects of boron (B) deficiency on bone healing by using this model. Weanling Wistar rats were divided into two groups: control (+B; 3 mg B/kg diet), and ...

  9. Cross-Face Nerve Grafting with Infraorbital Nerve Pathway Protection: Anatomic and Histomorphometric Feasibility Study

    PubMed Central

    Catapano, Joseph; Demsey, Daniel R.B.; Ho, Emily S.; Zuker, Ronald M.

    2016-01-01

    Smiling is an important aspect of emotional expression and social interaction, leaving facial palsy patients with impaired social functioning and decreased overall quality of life. Although there are several techniques available for facial reanimation, staged facial reanimation using donor nerve branches from the contralateral, functioning facial nerve connected to a cross-face nerve graft (CFNG) is the only technique that can reliably reproduce an emotionally spontaneous smile. Although CFNGs provide spontaneity, they typically produce less smile excursion than when the subsequent free functioning muscle flap is innervated with the motor nerve to the masseter muscle. This may be explained in part by the larger number of donor motor axons when using the masseter nerve, as studies have shown that only 20% to 50% of facial nerve donor axons successfully cross the nerve graft to innervate their targets. As demonstrated in our animal studies, increasing the number of donor axons that grow into and traverse the CFNG to innervate the free muscle transfer increases muscle movement, and this phenomenon may provide patients with the benefit of improved smile excursion. We have previously shown in animal studies that sensory nerves, when coapted to a nerve graft, improve axonal growth through the nerve graft and improve muscle excursion. Here, we describe the feasibility of and our experience in translating these results clinically by coapting the distal portion of the CFNG to branches of the infraorbital nerve. PMID:27757349

  10. Histopathologic and histomorphometric studies and determination of IL-8 in patients with periodontal disease

    PubMed Central

    Koss, Myriam A.; Castro, Cecilia E.; Carino, Silvia; López, Maria E.

    2014-01-01

    Background: Periodontitis is an inflammatory disease characterized by connective tissue breakdown and alveolar bone resorption. Objective: The aim of this study was to make a quantitative evaluation of the gingival tissue components in biopsies from patients with different clinical states of periodontal disease and to determine the relationship between the presence of interleukin-8 and the tissue destruction. Materials and Methods: The study group consisted of 33 biopsies from adult subjects. A total of 25 periodontal patients were sub-classified on the basis of the clinical and radiographic criteria in mild, moderate and advanced periodontitis. Gingival samples were obtained from patients in the course of basic periodontal surgeries as a muco-periostic collate. Data were analyzed by the SPSS system. Results: Collagen fibres decreased as non-specific chronic states increased. A lymphocyte inflammatory infiltrate changed to a lymphoplasmocytary form. Reactivity to interleukin-8 was detected with the severity of the histopathologic diagnoses; however there was no association with the clinical diagnoses. Conclusions: Histopathology and histomorphometry of gingival tissue changed with the degree of inflammation. No evidence of interleukin-8 as a biomarker for clinical diagnoses of periodontitis was obtained. PMID:24872619

  11. Effects of simultaneous nicotine and alcohol use in periodontitis progression in rats: A histomorphometric study

    PubMed Central

    Dias da Silva, Marco A.; Rocha Marques, Marcelo; Gibilini, Cristina; Cardoso Guimarães Vasconcelos, Any C.; Pereira Barros, Silvana

    2013-01-01

    Objective: The aim of this study was to evaluate the effects of alcohol and nicotine, when used alone or simultaneously, on the alveolar bone loss area resulting from ligature-induced periodontitis in rats. Study design: Forty adult male rats received a cotton ligature in the first lower molar sulcular area, and the animals were randomly assigned to different treatments (n = 10, each group) including daily peritoneal injections of saline solution (group A), submitted to self-administration of alcohol 25% (group B), nicotine solution in concentration 0.19 μl/ml (group C), and nicotine solution in concentration 0.19 μl/ml plus self-administration of alcohol 25% (group D). Five weeks later, the animals were sacrificed, and the samples were routinely processed for semi-serial decalcified sections. Results: Ligated teeth showed more alveolar bone loss than unligated ones (p < 0.05). Unligated teeth showed no significant differences between each other (p > 0.05). Analyses between the ligated teeth showed that the group C (nicotine) or group B (alcohol 25%) each had increasing alveolar bone loss in the furcation area, and the simultaneous combination alcohol and nicotine (group D) intensified these effects (p < 0.05). Conclusion: The results suggest that the simultaneous combination of alcohol and nicotine have a synergistic effect in the progression of periodontitis, evidenced by increased furcation region bone destruction in periodontal disease in rats. Key words:Alveolar bone loss, periodontitis, nicotine, alcohol, rats. PMID:24455064

  12. A comparison of histomorphometric data collection methods.

    PubMed

    Stewart, Marissa C; McCormick, Lara E; Goliath, Jesse R; Sciulli, Paul W; Stout, Sam D

    2013-01-01

    Although many variables that skeletal biologists examine have been standardized, the actual techniques used to collect these data from bone thin sections vary. This project compares different methods of obtaining data (relative cortical area values) for histomorphometric research. One visual and three digital methods of histomorphometric data collection are compared: (i) Merz microscopic eyepiece counting reticule, (ii) flatbed scanner, (iii) overlaying multiple images of a thin section, and (iv) digital SLR camera with macro settings. The discussion includes a comparison of usability factors such as cost, time, user-experience, and ease-of-use, which vary for each method. Values from the different methods are compared using ANOVA tests to evaluate inter-method, inter-observer, and intra-observer variability. Intra-observer error was greater for the microscopic method, although the error values are concomitant with experience. We found no statistically significant differences between the four methods examined, but certain caveats must be addressed when these methods are used.

  13. HISTOMORPHOMETRIC ANALYSIS OF PURE TITANIUM IMPLANTS WITH POROUS SURFACE VERSUS ROUGH SURFACE

    PubMed Central

    Brentel, Aline Scalone; de Vasconcellos, Luana Marotta Reis; Oliveira, Marize Varella; Graça, Mário Lima de Alencastro; de Vasconcellos, Luis Gustavo Oliveira; Cairo, Carlos Alberto Alves; Carvalho, Yasmin Rodarte

    2006-01-01

    The purpose of this study was to analyze the bone repair around commercially pure titanium implants with rough and porous surface, fabricated using powder metallurgy technique, after their insertion in tibiae of rabbits. Seven male rabbits were used. Each animal received 3 porous-surface implants in the left tibia and 3 rough-surface implants in the right tibia. The rabbits were sacrificed 4 weeks after surgery and fragments of the tibiae containing the implants were submitted to histological and histomorphometric analyses to evaluate new bone formation at the implant-bone interface. Means (%) of bone neoformation obtained in the histomorphometric analysis were compared by Student's t-test for paired samples at 5% significance level.. The results of the histological analysis showed that osseointegration occurred for both types of implants with similar quality of bone tissue. The histomorphometric analysis revealed means of new bone formation at implant-bone interface of 79.69 ± 1.00% and 65.05 ± 1.23% for the porous- and rough-surface implants, respectively. Statistically significant difference was observed between the two types of implants with respect to the amount new bone formation (p<0.05). In conclusion, the porous-surface implants contributed to the osseointegration because they provide a larger contact area at implant-bone interface. PMID:19089076

  14. Blood-filled spaces with and without deproteinized bone grafts in guided bone regeneration. A histomorphometric study of the rabbit skull using non-resorbable membrane.

    PubMed

    Okazaki, Kousuke; Shimizu, Yoshinaka; Xu, Hui; Ooya, Kiyoshi

    2005-04-01

    This experimental study evaluated the effects of deproteinized bone grafts on guided bone regeneration (GBR). A groove was made in the bone marrow of the external cortical plate of the skull. A dome of non-resorbable membrane was placed on the groove and secured with titanium pins. The secluded graft space was filled with autogenous blood clots (control group) and deproteinized bone particles (experimental group). The rabbits were sacrificed 2, 4, 8 and 12 weeks after the operation. Decalcified and paraffin-embedded, transverse 3-mum-thick sections were made and stained with hematoxylin and eosin. The proportions of newly formed bone and newly formed bone-graft particle contact surfaces were histomorphometrically measured in the basal, central, and peripheral areas from the cortical plate to the top of the dome. In the control group, the basal area showed a significant increase at 4 weeks (P<0.01) and a significant decrease at 8 weeks (P<0.01). The central and peripheral areas showed gradual increases in the proportion of newly formed bone. The experimental group showed significant increase at 4 weeks in the basal area and at 8 weeks in central and peripheral area (P<0.01). There were significant differences between both groups in basal and central area (P<0.01). The proportion of newly formed bone-graft particle contact length showed significant increases at 4 weeks (P<0.01) and no significant decreases at 8 and 12 weeks in three areas. The present study showed that deproteinized bone grafts maintain newly formed bone in extensive areas for a prolonged period during GBR.

  15. The influence of micro and macro-geometry in term of bone-implant interface in two implant systems: an histomorphometrical study

    PubMed Central

    ROCCI, A.; CALCATERRA, R.; DI GIROLAMO, M.; ROCCI, M.; ROCCI, C.; BAGGI, L.

    2015-01-01

    SUMMARY Objective Many factors could affect the osseous healing of implants such as surface topography of biomaterial, the status of the bone/implant site, implant loading conditions, surgical technique and implant design. The aim of this study was to analyze the BIC of 2 different implants systems characterized by different micro and macrogeometry, that were placed in the posterior maxillary and mandibular jaws of humans, clinically unloaded and retrieved for histomorphometric analyses after 12 weeks. Material and method The patients were divided in two groups (Group I and II); group I was composed by 4 patients that each received in the posterior areas of mandible one type A implant [GTB-Plan1Health Amaro (UD) Italy] one type B implant (OsseoSpeed Astra Tech, Dentsply Molndal, Sweden). Group II was composed by 3 patients that each received in the posterior areas of jawsbone one type A implant [GTB-Plan1Health Amaro (UD) Italy] one type B implant (OsseoSpeed Astra Tech, Dentsply Molndal, Sweden). After 12 weeks of healing all the implants of both groups were harvested with the peri-implant bone tissues. Osseointegration process was evaluated throughout measurements of BIC. Results No statistical significance differences were found among the mean percentage of BIC of Group I – type A were 66,51% versus 49,96% in Group I – type B, as well as among the mean percentage of BIC of Group II – type A were 43.7% versus 60.02% in Group II – type B. Conclusions Our results highlight that the mean percentage of BIC after 12 weeks from the implants placement without functional loading is not influenced by the composition of the implant surface. PMID:28042421

  16. Intermittent administration of parathyroid hormone improves the repairing process of rat calvaria defects: A histomorphometric and radiodensitometric study

    PubMed Central

    Silva, Eduardo-de-Paula; Marques, Marcelo-Rocha; Dias da Silva, Marco-Antônio; Manzi, Flávio-Ricardo; Barros, Silvana-Pereira

    2015-01-01

    Background The aim of this study was to evaluate the effects of intermittent treatment of parathyroid hormone (PTH (1-34)) on the bone regeneration of critically-sized rat calvarial bone defects. Material and Methods Thirty-two male rats were trephined (4mm fullthickness diameter), in the central part of the parietal bones and divided into 2 groups of 16. The PTH group received subcutaneous injections of PTH (1-34) at 40µg/kg, 3 times a week and the control (CTL) group received the vehicle in the same regimen. The rats were sacrificed at 4 weeks post-treatment regimen, the parietal bones were extracted and samples were evaluated through histomorphometry and radiodensitometry. Results The histological observations showed that the PTH group presented more “island-like” new bone between the defect margins with fibrous tissues than did the CTL group. The PTH group significantly exhibited greater histologic bone formation than did the CTL group (1.5mm ±0.7; 1.9 mm ± 0.6, p<0.05/ for residual bone defect). The radiodensitometry analysis revealed significant differences among the PTH and CTL groups (2.1 Al eq. ±0.04; 1.8Al eq. ±0.06, p<0.05), demonstrating an increase in bone mineral density. The PTH treatment contributed to the bone formation with a higher amount of mineral and/or fibrous tissue when compared with the CTL group. Conclusions The results suggest that it was possible to increase the process of bone regeneration by accelerating the healing process in rat calvarial defects through intermittent administration of the PTH treatment. Key words: Bone, skull, rats, bone regeneration, bone density. PMID:26034928

  17. Evaluation of Histomorphometric Changes in Tissue Architecture in Relation to Alteration in Fixation Protocol – An Invitro Study

    PubMed Central

    Singh, Narendra Nath; Sreedhar, Gadiputi; Banerjee, Sumita; Batra, Manu; Garg, Anu

    2016-01-01

    Introduction Preparation of good tissue specimens for microscopy requires complete fixation. No ideal fixative has been found till date, with every fixative showing advantages and disadvantages. Appropriate fixation is required to maintain clear and consistent morphologic features for histologic examination. Pathologists mostly examine formalin fixed tissue sections and are less used to the morphologic changes induced by other fixatives. Underfixed and overfixed tissue in various fixatives can lead to tissue architectural changes which can affect its diagnostic value. Aim To assess sectioning ability, staining intensity and microscopic details of tissues kept in different fixatives at different time intervals. Materials and Methods Fresh tissue specimen i.e., goat tongue was collected and its middle-third portion was used for the study purpose. The tissue was grossed into 10 equal pieces and kept in various fixatives (10% Buffered formalin, Carnoy’s solution, Absolute ethyl alcohol, Bouin’s fluid) for five different time intervals (6, 12, 18, 24 and 30 hours) and normal tissue processing steps were carried out followed by sectioning and staining. During sectioning, sectioning parameter was assessed. Following sectioning, sections were observed under light microscope and were histologically evaluated for staining and microscopic details. To calculate the sectioning parameter Fisher’s exact test was used and to assess parameters for staining and microscopic details Mann-Whitney U test was used. Results According to the study, 10% buffered formaldehyde is considered as a superior fixative under all parameters followed by Bouin’s fluid, Carnoy’s solution and Absolute alcohol. Conclusion In our study, it was concluded that 10% buffered formaldehyde should be continued as a routine fixative however, other fixatives can be used depending upon the non-availability of required fixative or in case of emergencies. Pathologist should be accustomed to histologic and

  18. Peri-implant bone reactions around immediately loaded conical implants with different prosthetic suprastructures: histological and histomorphometrical study on minipigs.

    PubMed

    Assenza, Bartolomeo; Scarano, Antonio; Perrotti, Vittoria; Vozza, Iole; Quaranta, Alessandro; Quaranta, Manlio; Piattelli, Adriano; Iezzi, Giovanna

    2010-06-01

    The aim of this study was to evaluate peri-implant bone reactions around immediately loaded conical implants with metal and acrylic resin prosthetic restorations. Five splinted conical implants were inserted in each hemimandible of six minipigs at the alveolar crest level. Ten implants were inserted in each minipig. All the implants were immediately loaded. The implants were divided into a group with an acrylic resin prosthetic restoration and into another group with a metal prosthetic restoration. No postoperative complications or deaths of the minipigs occurred. All minipigs were killed after 3 months. No implant was lost. A total of 60 implants were retrieved and processed to obtain thin ground sections. Histology and histomorphometry showed the presence of compact, mature bone around all the implants. Bone was in close contact with the implant surface starting from the first or second implant threads. A high quantity of mineralized bone was present around immediately loaded conical, root form implants. No differences in the peri-implant bone response were found in the groups with different prosthetic reconstructions.

  19. Isolation and Assessment of Mesenchymal Stem Cells Derived From Bone Marrow: Histologic and Histomorphometric Study in a Canine Periodontal Defect.

    PubMed

    Paknejad, Mojgan; Eslaminejad, Mohamadreza Baghaban; Ghaedi, Baharak; Rokn, Amir-Reza; Khorsand, Afshin; Etemad-Moghadam, Shahroo; Alaeddini, Mojgan; Dehghan, Mohammad Mehdi; Moslemi, Neda; Nowzari, Hessam

    2015-06-01

    The aim of the present study was to investigate an isolation procedure to culture mesenchymal stem cells derived from bone marrow and evaluate their potential in periodontal regeneration. Potential stem cells from bone marrow, aspirated from the iliac crest of nine mongrel canines 1 to 2 years of age, were cultivated. After the examination of surface epitopes of the isolated cells, the total RNA from osteogenic, adipogenic, and chondrogenic cell cultures were analyzed by reverse transcription polymerase chain reaction (RT-PCR) to confirm stem cell gene expressions. 2 × 10(7) mL of the stem cells were loaded on 0.2 mL of anorganic bovine bone mineral (ABBM) granules. In each animal, bilateral acute/chronic intrabony periodontal defects were created surgically and by placement of ligatures around the cervical aspect of the teeth. At week 5, after flap debridement, the bilateral defects were randomly assigned to 2 treatment groups: the control group received ABBM, and the test group received BMSCs-loaded ABBM. Eight weeks after transplantation, regenerative parameters were analyzed histologically and histometrically. The RNA expressions confirmed the cultivation of mesenchymal stem cell. More new cementum and periodontal ligament (PDL) were measured in the test group (cementum: 3.33 ± 0.94 vs 2.03 ± 1.30, P = 0.027; PDL: 2.69 ± 0.73 vs 1.53 ± 1.21, P = 0.026). New bone formation was similar in both groups (2.70 ± 0.86 vs 1.99 ± 1.31; P = 0.193). Mesenchymal stem cells derived from bone marrow should be considered a promising technique for use in patients with periodontal attachment loss and merits further investigations.

  20. Histomorphometric comparison after fixation with formaldehyde or glyoxal

    PubMed Central

    Wang, YN; Lee, K; Pai, S; Ledoux, WR

    2014-01-01

    Formaldehyde has long been the fixative of choice for histological examination of tissue. The use of alternatives to formaldehyde has grown, however, owing to the serious hazards associated with its use. Companies have striven to maintain the morphological characteristics of formaldehyde-fixed tissue when developing alternatives. Glyoxal-based fixatives now are among the most popular formaldehyde alternatives. Although there are many studies that compare staining quality and immunoreactivity, there have been no studies that quantify possible structural differences. Histomorphometric analysis commonly is used to evaluate diseased tissue. We compared fixation with formaldehyde and glyoxal with regard to the histomorphological properties of plantar foot tissue using a combination of stereological methods and quantitative morphology. We measured skin thickness, interdigitation index, elastic septa thickness, and adipocyte area and diameter. No significant differences were observed between formaldehyde and glyoxal fixation for any feature measured. The glyoxal-based fixative used therefore is a suitable fixative for structural evaluation of plantar soft tissue. Measurements obtained from the glyoxal-fixed tissue can be combined with data obtained from formalin-fixed for analysis. PMID:20854226

  1. Bioactive glass in cavitary bone defects: a comparative experimental study in rabbits

    PubMed Central

    Camargo, André Ferrari de França; Baptista, André Mathias; Natalino, Renato; de Camargo, Olavo Pires

    2015-01-01

    OBJECTIVES: To compare bioactive glass and autograft regarding their histomorphometric characteristics. METHODS: The authors conducted a prospective case-control experimental study on animals in order to compare the histomorphometric characteristics of bioactive glass versus autograft. Eight rabbits underwent surgery in which a cavitary defect was created in both proximal femurs. One side was filled with bioactive glass granules and the other, with autograft grafted from the contralateral side. The sides were randomized. Fourteen days after surgery, the animals were euthanized. RESULTS: Histologic analysis revealed that bone neoformation was equivalent among the two groups and the osteoblasts cell-count was higher in the femurs treated with bioactive glass. The osteocytes cell-count, however, was lower. The similarity in bone formation between both groups was consistent to literature findings. CONCLUSION: Bioactive glass is similar to autograft regarding bone neoformation in this animal model of cavitary bone defects. Level of Evidence III, Case-Control Study. PMID:26327802

  2. A histologic, histomorphometric, and radiographic comparison between two complexes of CenoBoen/CenoMembrane and Bio-Oss/Bio-Gide in lateral ridge augmentation: A clinical trial

    PubMed Central

    Amoian, Babak; Moudi, Ehsan; Majidi, Maryam Seyed; Ali Tabatabaei, S. M.

    2016-01-01

    Background: Several grafting materials have been used for alveolar ridge augmentation. The literature lacks researches to compare CenoBone to other grafting materials. The aim of this study was to compare CenoBone/CenoMembrane complex to Bio-Oss/Bio-Gide complex in lateral alveolar bone augmentation in terms of radiographic, histologic, and histomorphometric parameters. Materials and Methods: In this randomized controlled trial, ten patients who needed lateral ridge augmentation were selected and augmentations were done using either of CenoBone/CenoMembrane or Bio-Oss/Bio-Gide complexes. In the re-entry surgery in 6 months following augmentation, core biopsies were taken and clinical, radiographic, histologic, and histomorphometric evaluations were performed. Results: No statistically significant difference was seen between groups except for the number of blood vessels and percentage of residual graft materials. Conclusion: CenoBone seems to present a comparable lateral ridge augmentation to Bio-Oss in. PMID:27857771

  3. Gross, histological and histomorphometric features of the navicular bone and related structures in the horse.

    PubMed

    Wright, I M; Kidd, L; Thorp, B H

    1998-05-01

    Forelimb navicular bones and associated soft tissues were collected from 3 groups of horses and subjected to pathological examinations. The groups consisted of 38 horses with clinical navicular disease (ND) and 2 control groups, with no history of forelimb lameness, consisting of 25 age-matched mature horses (A-MC) and 9 immature horses (IC). Histological and histomorphometric studies were performed on tissue samples from 10 ND, 10 A-MC and 5 IC horses. Gross changes seen only in ND horses included: full thickness defects in the palmar surface fibrocartilage, palmar cortex erosion, medullary lysis, flexor digitorum profundus tendon (FDPT) surface fibrillation, FDPT core lesions and adhesions between the FDPT and navicular bone. Palmar surface partial thickness fibrocartilage loss and distal border fragmentation were seen with a significantly greater incidence in ND than in A-MC and not observed in IC. Remodelling of the proximal border, FDPT surface colouration, palmar surface fibrocartilage colouration and proximal border entheseous bone were identified in ND and A-MC but not in IC. Mid-ridge synovial fossae and horizontal depressions in the palmar surface were identified in all groups. Histologically palmar fibrocartilage thinning and loss were associated with reduced palmar fibrocartilage cell density and chondrocyte cluster formation. Palmar fibrocartilage fibrillation, palmar cortical bone defects, fibromyxoid stromal change in the medulla, medullary pseudocyst formation and entheseous new bone formation were all seen in ND. The adjacent FDPT showed fibrillation, tag formation and degeneration of the dorsal surface. Necrotic foci were also present within the body of the tendon. Although not always present, medullary bone pseudocysts, separate mineralised foci and most changes on the dorsal surface of the FDPT were specific to ND. Bone histomorphometric parameters were compared among groups. Cross-sectional area reduced from the sagittal ridge to the medial and

  4. Soft Tissue and Marginal Bone Adaptation on Platform-Switched Implants with a Morse Cone Connection: A Histomorphometric Study in Dogs.

    PubMed

    Bolle, Caroline; Gustin, Marie-Paule; Fau, Didier; Boivin, Georges; Exbrayat, Patrick; Grosgogeat, Brigitte

    2016-01-01

    The purpose of this study was to investigate peri-implant tissue adaptation on platform-switched implants with a Morse cone-type connection, after 3 and 12 weeks of healing in dogs. Ten weeks after mandibular premolar extractions, eight beagle dogs received three implants each. At each biopsy interval, four animals were sacrificed and biopsies were processed for histologic analysis. The height of the peri-implant mucosa was 2.32 mm and 2.88 mm, respectively, whereas the bone level in relation to the implant platform was -0.39 mm and -0.67 mm, respectively, after 3 and 12 weeks of healing. Within the limits of the present study, platform-switched implants exhibited reduced values of biologic width and marginal bone loss when compared with previous data.

  5. Polyether ether ketone implants achieve increased bone fusion when coated with nano-sized hydroxyapatite: a histomorphometric study in rabbit bone.

    PubMed

    Johansson, Pär; Jimbo, Ryo; Naito, Yoshihito; Kjellin, Per; Currie, Fredrik; Wennerberg, Ann

    2016-01-01

    Polyether ether ketone (PEEK) possesses excellent mechanical properties similar to those of human bone and is considered the best alternative material other than titanium for orthopedic spine and trauma implants. However, the deficient osteogenic properties and the bioinertness of PEEK limit its fields of application. The aim of this study was to limit these drawbacks by coating the surface of PEEK with nano-scaled hydroxyapatite (HA) minerals. In the study, the biological response to PEEK, with and without HA coating, was investigated. Twenty-four screw-like and apically perforated implants in the rabbit femur were histologically evaluated at 3 weeks and 12 weeks after surgery. Twelve of the 24 implants were HA coated (test), and the remaining 12 served as uncoated PEEK controls. At 3 weeks and 12 weeks, the mean bone-implant contact was higher for test compared to control (P<0.05). The bone area inside the threads was comparable in the two groups, but the perforating hole showed more bone area for the HA-coated implants at both healing points (P<0.01). With these results, we conclude that nano-sized HA coating on PEEK implants significantly improved the osteogenic properties, and in a clinical situation this material composition may serve as an implant where a rapid bone fusion is essential.

  6. Polyether ether ketone implants achieve increased bone fusion when coated with nano-sized hydroxyapatite: a histomorphometric study in rabbit bone

    PubMed Central

    Johansson, Pär; Jimbo, Ryo; Naito, Yoshihito; Kjellin, Per; Currie, Fredrik; Wennerberg, Ann

    2016-01-01

    Polyether ether ketone (PEEK) possesses excellent mechanical properties similar to those of human bone and is considered the best alternative material other than titanium for orthopedic spine and trauma implants. However, the deficient osteogenic properties and the bioinertness of PEEK limit its fields of application. The aim of this study was to limit these drawbacks by coating the surface of PEEK with nano-scaled hydroxyapatite (HA) minerals. In the study, the biological response to PEEK, with and without HA coating, was investigated. Twenty-four screw-like and apically perforated implants in the rabbit femur were histologically evaluated at 3 weeks and 12 weeks after surgery. Twelve of the 24 implants were HA coated (test), and the remaining 12 served as uncoated PEEK controls. At 3 weeks and 12 weeks, the mean bone–implant contact was higher for test compared to control (P<0.05). The bone area inside the threads was comparable in the two groups, but the perforating hole showed more bone area for the HA-coated implants at both healing points (P<0.01). With these results, we conclude that nano-sized HA coating on PEEK implants significantly improved the osteogenic properties, and in a clinical situation this material composition may serve as an implant where a rapid bone fusion is essential. PMID:27103801

  7. Hemodynamic and histomorphometric characteristics of dilated cardiomyopathy of Syrian hamsters (Bio TO-2 strain).

    PubMed

    Goineau, S; Pape, D; Guillo, P; Ramée, M P; Bellissant, E

    2001-04-01

    The natural history of the disease of the dilated strain Bio TO-2 of cardiomyopathic hamsters (CMH) is not totally characterized. We investigated its hemodynamic and histomorphometric characteristics at 140, 180, 220, 260, and 300 days of age. Forty CMH and 40 controls were investigated (8 at each stage). Mean arterial pressure (MAP, carotid artery catheter) and cardiac output and femoral blood flow (CO, FBF, transit time method) were measured in anesthetized animals. Systemic (SVR) and femoral (FVR) vascular resistances were calculated. Atria, left and right ventricles (LV, RV), lungs, and liver were weighed. LV cavity area, LV and RV wall thicknesses and collagen densities were determined (computer-assisted image analyzer). Pulmonary and hepatic congestion were assessed (arbitrary scales). Compared with controls, MAP, CO and FBF were significantly lower in CMH throughout the study (on average: -22%, -34%, -33%, respectively), FVR was significantly increased (+15%), but SVR was not significantly modified. Concerning histomorphometric characteristics, differences between groups significantly increased with age for most variables: at 300 days, atria (+292%), RV (+13%), lungs (+44%), and liver (+23%) weights, LV cavity area (+130%), LV (+364%) and RV (+181%) collagen densities were significantly increased in CMH vs controls, whereas LV (-40%) and RV (-23%) wall thicknesses were significantly decreased. At 260 and 300 days, CMH showed significant pulmonary congestion without hepatic alteration. Bio TO-2 CMH progressively develop an alteration of cardiac function leading to decreased MAP and musculo-cutaneous blood flow associated with cardiac remodeling including atria hypertrophy and LV dilation, wall thinning and a rise in collagen density.

  8. Histomorphometric and histologic evaluation of titanium-zirconium (aTiZr) implants with anodized surfaces.

    PubMed

    Sharma, Ajay; McQuillan, A James; Shibata, Yo; Sharma, Lavanya A; Waddell, John Neil; Duncan, Warwick John

    2016-05-01

    The choice of implant surface has a significant influence on osseointegration. Modification of TiZr surface by anodization is reported to have the potential to modulate the osteoblast cell behaviour favouring more rapid bone formation. The aim of this study is to investigate the effect of anodizing the surface of TiZr discs with respect to osseointegration after four weeks implantation in sheep femurs. Titanium (Ti) and TiZr discs were anodized in an electrolyte containing DL-α-glycerophosphate and calcium acetate at 300 V. The surface characteristics were analyzed by scanning electron microscopy, electron dispersive spectroscopy, atomic force microscopy and goniometry. Forty implant discs with thickness of 1.5 and 10 mm diameter (10 of each-titanium, titanium-zirconium, anodized titanium and anodized titanium-zirconium) were placed in the femoral condyles of 10 sheep. Histomorphometric and histologic analysis were performed 4 weeks after implantation. The anodized implants displayed hydrophilic, porous, nano-to-micrometer scale roughened surfaces. Energy dispersive spectroscopy analysis revealed calcium and phosphorous incorporation into the surface of both titanium and titanium-zirconium after anodization. Histologically there was new bone apposition on all implanted discs, slightly more pronounced on anodised discs. The percentage bone-to-implant contact measurements of anodized implants were higher than machined/unmodified implants but there was no significant difference between the two groups with anodized surfaces (P > 0.05, n = 10). The present histomorphometric and histological findings confirm that surface modification of titanium-zirconium by anodization is similar to anodised titanium enhances early osseointegration compared to machined implant surfaces.

  9. Photodamage in feline skin: clinical and histomorphometric analysis.

    PubMed

    Almeida, E M P; Caraça, R A; Adam, R L; Souza, E M; Metze, K; Cintra, M L

    2008-05-01

    The purpose of this study was to investigate clinical and histomorphometric features of cat skin under long-term solar exposure. Ear skin of 34 Domestic Shorthair cats that were chronically exposed to sun was classified as follows: group 0, normal (n = 13); group 1, initial stage of photodamage (PD) (n = 10); group 2, advanced stage of PD (n = 11). Histologic sections were examined independently by 2 pathologists, and epidermal thickness, adnexal unit area, and dermal cellularity were assessed by morphometry. A positive correlation was obtained between age, degree of edema and sclerosis in the upper dermis, telangiectases, squamatization of basal keratinocytes, and epidermis thickness and the degree of PD. The area occupied by adnexal structures in the dermis diminished with increased PD. Dermal sclerosis and edema best separated the 3 groups. The results indicated a high level of skin hypersensitivity to sun rays in cats. The findings may be useful for clinical testing and in general veterinary pathology and dermatology.

  10. Histomorphometric and proteomic analysis of the acute rabbit corneal tissue response following in vitro exposure to 1540-nm laser light

    NASA Astrophysics Data System (ADS)

    Eurell, Thomas E.; Johnson, Thomas E.; Roach, William P.

    2003-06-01

    In vitro exposures of explant rabbit corneas to single pulse 1540 nm infrared laser light operating at a pulse width of 0.8 milliseconds resulted in coagulative necrosis of both the corneal epithelium and stroma. Histomorphometric data correlated with increasing tissue radiant exposures. Histologic alterations in the corneal stroma were typical of matrix remodeling within the beam path and reactive to antibodies against matrix metalloproteinase-2. A two-dimensional electrophoretic analysis, using a mini-gel format, was developed to determine if specific corneal protein changes within tissue sections could be detected. Frozen sections taken through the center of the laser lesion were evaluated for proteomic data using tissue isoelectric focusing in the first dimension and polyacrylamide gel electrophoresis in the second dimension. Histomorphometric data describing the extent of the laser lesions were compared to the isoelectric points, molecular weights and relative densities of individual corneal proteins. Increasing radiant exposures of corneal tissues were associated with characteristic histomorphometric and proteomic changes.

  11. Comparative Packaging Study

    NASA Technical Reports Server (NTRS)

    Perchonok, Michele; Antonini, David

    2008-01-01

    This viewgraph presentation describes a comparative packaging study for use on long duration space missions. The topics include: 1) Purpose; 2) Deliverables; 3) Food Sample Selection; 4) Experimental Design Matrix; 5) Permeation Rate Comparison; and 6) Packaging Material Information.

  12. Early osseointegration of implants with cortex-like TiO2 coatings formed by micro-arc oxidation: A histomorphometric study in rabbits.

    PubMed

    Zhou, Hong-Zhi; Li, Ya-da; Liu, Lin; Chen, Xiao-Dong; Wang, Wei-Qiang; Ma, Guo-Wu; Su, Yu-Cheng; Qi, Min; Shi, Bin

    2017-02-01

    In our previous studies, a novel cortex-like TiO2 coating was prepared on Ti surface through micro-arc oxidation (MAO) by using sodium tetraborate as electrolyte, and the effects of the coating on cell attachment were testified. This study aimed to investigate the effects of this cortex-like MAO coating on osseointegration. A sand-blasting and acid-etching (SLA) coating that has been widely used in clinical practice served as control. Topographical and chemical characterizations were conducted by scanning electron microscopy, energy dispersive X-ray spectrometer, X-ray diffraction, contact angle meter, and step profiler. Results showed that the cortex-like coating had microslots and nanopores and it was superhydrophilic, whereas the SLA surface was hydrophobic. The roughness of MAO was similar to that of SLA. The MAO and SLA implants were implanted into the femoral condyles of New Zealand rabbits to evaluate their in-vivo performance through micro-CT, histological analysis, and fluorescent labeling at the bone-implant interface four weeks after surgery. The micro-CT showed that the bone volume ratio and mean trabecular thickness were similar between MAO and SLA groups four weeks after implantation. Histological analysis and fluorescent labeling showed no significant differences in the bone-implant contact between the MAO and SLA surfaces. It was suggested that with micro/nanostructure and superhydrophilicity, the cortex-like MAO coating causes excellent osseointegration, holding a promise of an application to implant modification.

  13. Dynamics of bone healing after osteotomy with piezosurgery or conventional drilling – histomorphometrical, immunohistochemical, and molecular analysis

    PubMed Central

    2013-01-01

    Background Piezosurgery is an osteotomy system used in medical and dental surgery. Many studies have proven clinical advantages of piezosurgery in terms of quality of cut, maneuverability, ease of use, and safety. However, few investigations have tested its superiority over the traditional osteotomy systems in terms of dynamics of bone healing. Therefore, the aim of this study was to evaluate the dynamics of bone healing after osteotomies with piezosurgery and to compare them with those associated to traditional bone drilling. Methods One hundred and ten rats were divided into two groups with 55 animals each. The animals were anesthetized and the tibiae were surgically exposed to create defects 2 mm in diameter by using piezosurgery (Piezo group) and conventional drilling (Drill group). Animals were sacrificed at 3, 7, 14, 30 and 60 days post-surgery. Bone samples were collected and processed for histological, histomorphometrical, immunohistochemical, and molecular analysis. The histological analysis was performed at all time points (n = 8) whereas the histomorphometrical analysis was performed at 7, 14, 30 and 60 days post-surgery (n = 8). The immunolabeling was performed to detect Vascular Endothelial Growth Factor (VEGF), Caspase-3 (CAS-3), Osteoprotegerin (OPG), Receptor Activator of Nuclear Factor kappa-B Ligand (RANKL), and Osteocalcin (OC) at 3, 7, and 14 days (n = 3). For the molecular analysis, animals were sacrificed at 3, 7 and 14 days, total RNA was collected, and quantification of the expression of 21 genes related to BMP signaling, Wnt signaling, inflammation, osteogenenic and apoptotic pathways was performed by qRT-PCR (n = 5). Results Histologically and histomorphometrically, bone healing was similar in both groups with the exception of a slightly higher amount of newly formed bone observed at 30 days after piezosurgery (p < 0.05). Immunohistochemical and qRT-PCR analyses didn’t detect significant differences in

  14. Histomorphometric evaluation of experimentally induced colitis with trinitrobenzene-sulphonic acid in rats

    PubMed Central

    RABAU, MICHA; EYAL, AMI; DAYAN, DAN

    1996-01-01

    Colitis was induced with trinitrobenzene-sulphonic acid (TNB) in rats and a histomorphometric study was performed as a possible scoring system for disease activity. The affected colon was examined 10, 20, 40 and 60 days after TNB administration. Quantitative microscopic analysis was performed on the following histologic parameters: necrosis, mucosal epithelium, muscularis fibres, inflammation, granulation tissue and fibrosis. Clinically, the rats were sick, especially on days 10 and 20 after TNB injection. Concomitantly, a peak necrosis score involving the full thickness of the colonic wall was recorded on day 10. The inflammatory reaction was most intense 20 days after TNB injection. After 60 days, marked epithelial regeneration was seen and most of the inflammatory reaction had subsided. A good correlation was found between clinical features and quantitative histomorphometric characteristics of colitis. The criteria described allow a precise description and quantification of the inflammatory and healing process of TNB-induced colitis in rats. PMID:8943736

  15. Distraction osteogenesis of the porcine mandible: histomorphometric evaluation of bone.

    PubMed

    Glowacki, Julie; Shusterman, E Mark; Troulis, Maria; Holmes, Ralph; Perrott, David; Kaban, Leonard B

    2004-02-01

    Distraction osteogenesis is a technique for skeletal lengthening that exploits the body's innate capacity for bone formation in response to tension forces on the repair callus. The authors developed a distraction osteogenesis model with a semiburied device in the Yucatan minipig mandible because of similarities between human and porcine mandibular anatomy, temporomandibular function, chewing patterns, and bone turnover rates. The purpose of this study was to measure histomorphometric bone fill after different latency periods, rates of distraction, and duration of neutral fixation in the minipig mandible. In addition, the relationship between histomorphometric bone fill and clinical stability was investigated. Mandibular osteotomies in 20 female Yucatan minipigs weighing 25 to 30 kg were distracted with modified semiburied distraction devices. Variables included 0-day or 4-day latency; 1-mm, 2-mm, or 4-mm daily distraction rates; gap size of 7 or 12 mm; and evaluation after neutral fixation for various lengths of time. Specimens were fixed in 2% paraformaldehyde, pH 7.4, before being embedded in methylmethacrylate. Sections were prepared from the region just below the inferior alveolar canal. The area of new bone formation within the gap was measured and expressed as a percentage of the total area of the distraction gap. Bone fill ranged from 0 to 100 percent. A pilot study with 7-mm advancements showed similar bone fill with 0-day or 4-day latency, but with poor reproducibility. Mandibles that were distracted to 12 mm at 1 mm per day exhibited nearly complete bone fill, either with 0-day latency (average, 93 percent) or 4-day latency (average, 100 percent). Mandibles that had been distracted for 3 days at 4 mm per day showed moderate osteogenesis and clinical stability with increasing time of neutral fixation. Bone fill was significantly correlated with clinical stability (Spearman r = 0.801, p = 0.001). Histological examination showed exuberant periosteal

  16. Effect of calcitonin on bone regeneration in male rats: a histomorphometric analysis.

    PubMed

    Almeida, J D; Arisawa, E A L; da Rocha, R F; Carvalho, Y R

    2007-05-01

    The aim of this study was to evaluate the effectiveness of calcitonin in promoting bone growth in surgical bone defects in rat mandibles. Fifty male rats were divided into two groups: bone defect (control) and bone defect with calcitonin (experimental). A circular bone defect 4mm in diameter was made in the mandibular bone of the rats in the angle region, and covered with a polytetrafluoroethylene barrier. The experimental group received 2 IU/kg of synthetic salmon calcitonin intramuscularly three times a week, with treatment starting immediately after surgery. The animals were killed 3, 7, 14, 21 and 28 days after the surgical procedure. The bone defects were examined histologically and by histomorphometric analysis. The Student t-test was applied to the histomorphometric data, with the level of significance set at 5%. The animals of the experimental group showed a lower level of bone formation at almost all time points than the control group, but no difference between groups was observed 28 days after surgery. The volume of newly formed bone matrix was significantly greater in the control than the experimental group at 7, 14 and 21 days, as determined by both morphologic and histomorphometric analysis. Bone repair in the calcitonin-treated animals was delayed in comparison to controls, indicating the need for further studies on male rats.

  17. [Pathobiological determinants of atherosclerosis in youths: data from a macromorphometric and histomorphometric investigation of the aorta and coronary arteries].

    PubMed

    Lesauskaite, Vaiva; Stalioraityte, Elena; Tanganelli, Piero; Epistolato, Maria Carmela

    2004-01-01

    We present a review of data from epidemiological and morphological studies carried out in Kaunas of atherosclerosis in youths. Since 1985, Kaunas has been a Collaborating Center involved with the World Health Organization and International Society and Federation of Cardiology studying the pathobiological determinants of atherosclerosis in youth. During the pilot study (1985-1987), we estimated the prevalence and extent of atherosclerotic lesions in the aorta and coronary arteries correlated to various risk factors in Kaunas residents aged 5 to 44 years. Within the framework of this international study, we compared histomorphometric characteristics of arteries collected from trauma victims aged 5 to 34 years in Budapest (Hungary), Heidelberg (Germany), Kaunas (Lithuania), Yaounde (Cameroon), and Mexico City (Mexico). These data revealed that males from countries with a high mortality from ischemic heart disease (Hungary, Lithuania, Germany) tended to have thicker intima in the thoracic and abdominal aorta and left anterior descending coronary artery than did males from countries with low mortality from ischemic heart disease (Mexico, Cameroon). We detected an increased mean intimal thickness of the abdominal aorta in male smokers aged 25-34 years. Males with hypertension aged 15-24 and 25-34 years had a thicker intima in the aorta and left anterior descending coronary artery than normotensive males. The morphological and epidemiological studies of atherosclerosis in youths carried out in Kaunas demonstrated that aortic and coronary atherosclerotic lesions appeared as early as childhood and advanced until the lesions become clinically apparent in adulthood. Histomorphometric findings support the postulate that increased intimal thickness can be considered a structural determinant of atherogenesis. These data draw attention to the means for the primary prevention of atherosclerosis in youth.

  18. Histomorphometric changes of small intestine in pregnant rat.

    PubMed

    Sabet Sarvestani, Fatemeh; Rahmanifar, Farhad; Tamadon, Amin

    2015-01-01

    Food intake of rats increases during pregnancy. This requires changes in the structure of the small intestine to absorb additional food. The aim of the present study was to investigate the morphological changes in the layers of small intestine in rats during pregnancy. Duodenum, jejunum and ileum of 18 pregnant Sprague-Dawley rats (day 7, 14 and 21 of pregnancy) were collected. Villous height and width and thickness of lamina propria, tunica muscularis entirely and separately (circular and longitudinal layers) were measured on transverse sections. During pregnancy increasing villi length and muscular layer thickness was observed in duodenum. Furthermore, along with the progress of gestation greatest histomorphometric change in small intestine was observed in the jejunum. The reduction in the ileum histomorphologic indices was observed during pregnancy. In conclusion, increase in histomorphologic indices of duodenum and jejunum supplies more capacity of duodenum to digest food intake during pregnancy and decrease in these indices in ileum controls the absorption of excess produced amino acids and glucose by hyperphagia.

  19. Comparative study on the osseointegration of implants in dog mandibles according to the implant surface treatment

    PubMed Central

    2016-01-01

    Objectives This study compared the impact of implant surface treatment on the stability and osseointegration of implants in dog mandibles. Materials and Methods Six adult dogs received a total of 48 implants that were prepared using four different surface treatments; resorbable blast media (RBM), hydroxyapatite (HA), hydrothermal-treated HA, and sand blasting and acid etching (SLA). Implants were installed, and dogs were separated into 2- and 4-week groups. Implant stability was evaluated via Periotest M, Osstell Mentor, and removal torque analyzers. A histomorphometric analysis was also performed. Results The stability evaluation showed that all groups generally had satisfactory values. The histomorphometric evaluation via a light microscope revealed that the HA surface implant group had the highest ratio of new bone formation on the entire fixture. The hydrothermal-treated HA surface implant group showed a high ratio of bone-to-implant contact in the upper half of the implant area. Conclusion The hydrothermal-treated HA implant improved the bone-to-implant contact ratio on the upper fixture, which increased the implant stability. PMID:28053904

  20. Low-level laser therapy affects osseointegration in titanium implants: resonance frequency, removal torque, and histomorphometric analysis in rabbits

    PubMed Central

    2016-01-01

    Objectives The purpose of this study was to investigate the effects of low-level laser therapy (LLLT) with a diode gallium-aluminum-arsenide (Ga-Al-As) low-level laser device on the healing and attachment of titanium implants in bone. Materials and Methods Thirteen New Zealand white male rabbits weighing 3.0±0.5 kg were used for this study. Dental titanium implants (3.75 mm in diameter and 8.5 mm in length, US II RBM plus fixture; Osstem, Seoul, Korea) were implanted into both femurs of each rabbit. The rabbits were randomly divided into a LLLT group and a control group. The LLLT was initiated immediately after surgery and then repeated daily for 7 consecutive days in the LLLT group. Six weeks and 12 weeks after implantation, we evaluated and compared the osseointegration of the LLLT group and control group, using histomorphometric analysis, removal torque testing, and resonance frequency analysis (RFA). The results were statistically significant when the level of probability was 0.05 or less based on a non-parametric Mann-Whitney U-test. Results The implant survival rate was about 96%. Histologically and histomorphometrically, we observed that the titanium implants were more strongly attached in LLLT group than in control group. However, there was no significant difference between the LLLT group and control group in removal torque or RFA. Conclusion Histologically, LLLT might promote cell-level osseointegration of titanium implants, but there was no statistically significant effects. PMID:26904488

  1. Calcitonin in bone-guided regeneration of mandibles in ovariectomized rats: densitometric, histologic and histomorphometric analysis.

    PubMed

    Arisawa, E A L; Brandão, A A H; Almeida, J D; da Rocha, R F

    2008-01-01

    The aim of the present study was to investigate bone promotion in surgical defects created in the mandible of normal and ovariectomized female rats using calcitonin associated with a polytetrafluoroethylene barrier. The 100 female rats were divided into four groups: control (C), control treated with calcitonin (CM), ovariectomized control (OV) and ovariectomized treated with calcitonin (OVM). A circumscribed bone defect 4mm in diameter was created in the region of the mandibular angle, and covered with the barrier. Groups CM and OVM received 2 IU/kg of synthetic salmon calcitonin intramuscularly three times a week. The animals were killed 3, 7, 14, 21 and 28 days after surgery. The bone defects were submitted to densitometric, histologic and histomorphometric analysis. Groups C and CM showed higher levels of bone formation after 7 days compared to the OV and OVM groups. A significant difference was observed between groups C and OV at 3-14 days. The OV group presented slower bone regeneration of the surgical bone defect created in the mandibular angle than group C. Synthetic salmon calcitonin accelerated regeneration of the bone defect in the mandibles of OVM animals similarly to group C, and also increased the formation of new bone during the regeneration process in CM.

  2. The spermatogenic process of the common vampire bat Desmodus rotundus under a histomorphometric view

    PubMed Central

    Puga, Luciano Carlos Heringer Porcaro; de Paula, Tarcízio Antônio Rêgo; Freitas, Mariella Bontempo Duca; da Matta, Sérgio Luis Pinto

    2017-01-01

    Among all bat species, Desmodus rotundus stands out as one of the most intriguing due to its exclusively haematophagous feeding habits. However, little is known about their spermatogenic cycle. This study aimed at describing the spermatogenic process of common vampire bats through testicular histomorphometric characterization of adult specimens, spermatogenic production indexes, description of stages of the seminiferous epithelium cycle and estimative of the spermatogenic process duration. Morphometrical and immunohistochemical analyzes for bromodeoxiuridine were conducted under light microscopy and ultrastructural analyzes were performed under transmission electron microscopy. Vampire bats showed higher investment in gonadal tissue (gonadosomatic index of 0.54%) and in seminiferous tubules (tubulesomatic index of 0.49%) when compared to larger mammals. They also showed a high tubular length per gram of testis (34.70 m). Approximately half of the intertubular compartment was found to be comprised by Leydig cells (51.20%), and an average of 23.77x106 of these cells was found per gram of testis. The germline cells showed 16.93% of mitotic index and 2.51% of meiotic index. The overall yield of spermatogenesis was 60% and the testicular spermatic reserve was 71.44x107 spermatozoa per gram of testis. With a total spermatogenesis duration estimated at 37.02 days, vampire bats showed a daily sperm production of 86.80x106 gametes per gram of testis. These findings demonstrate a high sperm production, which is commonly observed in species with promiscuous mating system. PMID:28301534

  3. The spermatogenic process of the common vampire bat Desmodus rotundus under a histomorphometric view.

    PubMed

    Morais, Danielle Barbosa; Puga, Luciano Carlos Heringer Porcaro; Paula, Tarcízio Antônio Rêgo de; Freitas, Mariella Bontempo Duca; Matta, Sérgio Luis Pinto da

    2017-01-01

    Among all bat species, Desmodus rotundus stands out as one of the most intriguing due to its exclusively haematophagous feeding habits. However, little is known about their spermatogenic cycle. This study aimed at describing the spermatogenic process of common vampire bats through testicular histomorphometric characterization of adult specimens, spermatogenic production indexes, description of stages of the seminiferous epithelium cycle and estimative of the spermatogenic process duration. Morphometrical and immunohistochemical analyzes for bromodeoxiuridine were conducted under light microscopy and ultrastructural analyzes were performed under transmission electron microscopy. Vampire bats showed higher investment in gonadal tissue (gonadosomatic index of 0.54%) and in seminiferous tubules (tubulesomatic index of 0.49%) when compared to larger mammals. They also showed a high tubular length per gram of testis (34.70 m). Approximately half of the intertubular compartment was found to be comprised by Leydig cells (51.20%), and an average of 23.77x106 of these cells was found per gram of testis. The germline cells showed 16.93% of mitotic index and 2.51% of meiotic index. The overall yield of spermatogenesis was 60% and the testicular spermatic reserve was 71.44x107 spermatozoa per gram of testis. With a total spermatogenesis duration estimated at 37.02 days, vampire bats showed a daily sperm production of 86.80x106 gametes per gram of testis. These findings demonstrate a high sperm production, which is commonly observed in species with promiscuous mating system.

  4. Fractal dimension of trabecular bone: comparison of three histomorphometric computed techniques for measuring the architectural two-dimensional complexity.

    PubMed

    Chappard, D; Legrand, E; Haettich, B; Chalès, G; Auvinet, B; Eschard, J P; Hamelin, J P; Baslé, M F; Audran, M

    2001-11-01

    Trabecular bone has been reported as having two-dimensional (2-D) fractal characteristics at the histological level, a finding correlated with biomechanical properties. However, several fractal dimensions (D) are known and computational ways to obtain them vary considerably. This study compared three algorithms on the same series of bone biopsies, to obtain the Kolmogorov, Minkowski-Bouligand, and mass-radius fractal dimensions. The relationships with histomorphometric descriptors of the 2-D trabecular architecture were investigated. Bone biopsies were obtained from 148 osteoporotic male patients. Bone volume (BV/TV), trabecular characteristics (Tb.N, Tb.Sp, Tb.Th), strut analysis, star volumes (marrow spaces and trabeculae), inter-connectivity index, and Euler-Poincaré number were computed. The box-counting method was used to obtain the Kolmogorov dimension (D(k)), the dilatation method for the Minkowski-Bouligand dimension (D(MB)), and the sandbox for the mass-radius dimension (D(MR)) and lacunarity (L). Logarithmic relationships were observed between BV/TV and the fractal dimensions. The best correlation was obtained with D(MR) and the lowest with D(MB). Lacunarity was correlated with descriptors of the marrow cavities (ICI, star volume, Tb.Sp). Linear relationships were observed among the three fractal techniques which appeared highly correlated. A cluster analysis of all histomorphometric parameters provided a tree with three groups of descriptors: for trabeculae (Tb.Th, strut); for marrow cavities (Euler, ICI, Tb.Sp, star volume, L); and for the complexity of the network (Tb.N and the three D's). A sole fractal dimension cannot be used instead of the classic 2-D descriptors of architecture; D rather reflects the complexity of branching trabeculae. Computation time is also an important determinant when choosing one of these methods.

  5. Histopathology and Histomorphometric Investigation of Bisphenol A and Nonylphenol on the Male Rat Reproductive System

    PubMed Central

    Kazemi, Sohrab; Feizi, Farideh; Aghapour, Fahimaeh; Joorsaraee, Gholam Ali; Moghadamnia, Ali Akbar

    2016-01-01

    Background: Bisphenol A (BPA) and nonylphenol (NP) have harmful effects on the endocrine system of humans and animals. Aim: We sought to investigate the effect of three doses of BPA and NP on the reproductive parameters of rats. Materials and Methods: Adult Wistar male rats weighing 150–200 g were used for a consecutive 35-day study. BPA and NP were given as gavage in three doses (5, 25, and 125 μg/kg). At the end of the study, the rats were anesthetized and 2 ml blood sample was obtained from the auxiliary venous plexus for the assessment of sex hormone levels. The testes were removed and kept in 10% formalin for the histomorphometric and histopathologic analyses. Results: BPA and NP significantly decreased the body weight of the animals compared to the controls (P < 0.05). The seminiferous tubule diameter and thickness of the seminiferous epithelium were significantly decreased in the groups receiving BPA and NP compared to the control (P < 0.05). The number of seminiferous tubules in every experimental group increased, except for the highest dose of NP (125 μg/kg), which showed a significant difference compared to the controls (P < 0.05). The number of spermatocytes and spermatogonia (54.97 ± 5.824, 35.78 ± 3.956, respectively) in the group receiving NP (125 μg/kg) was significantly decreased compared to the other groups. Serum levels of luteinizing hormone, Follicle stimulating hormone, and testosterone did not show any significant change compared to the controls. Conclusion: Based on the results, all three doses of BPA and NP significantly produced weight loss, as well as destruction of the testis tissue and impairment of the spermatogenesis. PMID:27298816

  6. Comparative Packaging Study

    NASA Technical Reports Server (NTRS)

    Perchonok, Michele H.; Oziomek, Thomas V.

    2009-01-01

    Future long duration manned space flights beyond low earth orbit will require the food system to remain safe, acceptable and nutritious. Development of high barrier food packaging will enable this requirement by preventing the ingress and egress of gases and moisture. New high barrier food packaging materials have been identified through a trade study. Practical application of this packaging material within a shelf life test will allow for better determination of whether this material will allow the food system to meet given requirements after the package has undergone processing. The reason to conduct shelf life testing, using a variety of packaging materials, stems from the need to preserve food used for mission durations of several years. Chemical reactions that take place during longer durations may decrease food quality to a point where crew physical or psychological well-being is compromised. This can result in a reduction or loss of mission success. The rate of chemical reactions, including oxidative rancidity and staling, can be controlled by limiting the reactants, reducing the amount of energy available to drive the reaction, and minimizing the amount of water available. Water not only acts as a media for microbial growth, but also as a reactant and means by which two reactants may come into contact with each other. The objective of this study is to evaluate three packaging materials for potential use in long duration space exploration missions.

  7. The Murine Femoral Allograft Model and a Semi-automated Histomorphometric Analysis Tool

    PubMed Central

    Dhillon, Robinder S.; Zhang, Longze; Schwarz, Edward M.; Boyce, Brendan F.; Xie, Chao

    2014-01-01

    SUMMARY Preclinical studies on bone repair remain a high priority due to the unresolved clinical problems associated with treating critical segmental defects and complications of fracture healing. Over the last decade the murine femoral allograft model has gained popularity due to its standardized surgery and potential for examining a vast array of radiographic, biomechanical and histological outcome measures. Here, we describe these methods and a novel semi-automated histomorphometric approach to quantify the amount of bone, cartilage and undifferentiated mesenchymal tissue in demineralized paraffin sections of allografted murine femurs using the VisioPharm Image Analysis Software System. PMID:24482164

  8. Low-Level Laser Action on Orthodontically Induced Root Resorption: Histological and Histomorphometric Evaluation

    PubMed Central

    Vasconcelos, Eliziane Cossetin; Henriques, Jose Fernando Castanha; Sousa, Marinês Vieira Silva; de Oliveira, Rodrigo Cardoso; Consolaro, Alberto; Pinzan, Arnaldo; Henriques, Fernanda Pinelli; Bronfman, aroline Nemetz

    2016-01-01

    Introduction: Studies have been conducted to develop a means of preventing, controlling or reducing orthodontically induced root resorption. Phototherapy has demonstrated effectiveness as an anti-inflammatory and, considering the inflammatory origin of this pathology, this study evaluated the effects of laser on root resorption. Methods: The research was conducted among 54 80-day-old male Wistar rats, with weights of 280 ± 40 g. Phototherapy consisted of a diode laser (Ga-Al-As), calibrated with a wavelength of 808 nm, an output power of 100 mW, 2.1 J or 96 J of energy and area of 0.0028 cm2. The application was continuous, punctual and with contact. The left first maxillary molar was moved by a super-elastic closed spring with a pre-calibrated and constant force of 25 g. The specimens were irradiated every 48 hours, totaling three or six times, depending on the group to which they belonged. Euthanasia was made in the 7th or 10th day after the onset of movement. The histological and histomorphometric examination was performed with sections of 6 μm stained with hematoxylin and eosin (H&E). Results: Considering the dosimetry studied, when compared the subgroups with the same time of movement, 7 or 10 days, the low-level laser (LLL) has no statistically significant effect on the root resorption. As expected, differences were found between groups with different time of movement. Conclusion: Based on the result, this dosimetry does not seem to be clinically recommended to avoid or reduce inflammatory root resorption, but it also does not induce any root surface alteration. PMID:28144433

  9. Histomorphometric results of different grafting materials and effect of healing time on bone maturation after sinus floor augmentation: a systematic review and meta-analysis.

    PubMed

    Danesh-Sani, S A; Engebretson, S P; Janal, M N

    2016-08-18

    The aim of this systematic review was to evaluate histomorphometric variables, the amount of new bone (NB), residual graft (RG) particles and soft tissue (ST), related to various grafting materials and assess the effect of graft healing time on different histomorphometric outcomes. Studies that were published before October 2015 were electronically and manually searched in three databases. We included human studies that reported the amount of NB, RG and ST in the biopsies taken from the grafted sinuses. Based on the applied grafting materials, extracted data were categorized into different groups. Furthermore, extracted data were classified into three groups based on healing time: (i) ≤ 4.5 mo; (ii) 4.5-9 mo; and (iii) ≥ 9-13.5 mo. The search provided 791 titles. Full text analysis was performed for 258 articles resulting in 136 studies that met the inclusion criteria. Autogenous bone (AB) resulted in the highest amount of NB and lowest amount of RG compared to other grafting materials. Based on this meta-analysis, a significant difference was noticed in the amount of NB formation in grafts with a healing time of > 4.5 mo when compared to the grafts with less healing time. However, when comparing biopsies taken at 4.5-9 mo of healing (average = 6.22 mo) to the ones taken at ≥ 9-13.5 mo (average = 10.36 mo), no significant difference was noticed in the amount of NB formation of various grafts except allografts that resulted in a significantly higher percentage of NB at 9.5 mo of healing. Based on histomorphometric analysis, AB results in the highest amount of NB formation in comparison to the other grafting materials. Bone substitute materials (allografts, alloplastic materials and xenografts) seem to be good alternatives to autogenous bone and can be considered as grafting materials to avoid disadvantages related to AB, including morbidity rate, limited availability and high volumetric change. Combining AB with alloplastic materials and xenografts brings no

  10. Evaluation of an experimental rat model for comparative studies of bleaching agents

    PubMed Central

    CINTRA, Luciano Tavares Angelo; BENETTI, Francine; FERREIRA, Luciana Louzada; RAHAL, Vanessa; ERVOLINO, Edilson; JACINTO, Rogério de Castilho; GOMES, João Eduardo; BRISO, André Luiz Fraga

    2016-01-01

    ABSTRACT Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the coronal pulp occlusal third up to the 15-min application groups of each bleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents. PMID:27119766

  11. Evaluation of an experimental rat model for comparative studies of bleaching agents

    PubMed Central

    Cintra, Luciano Tavares Angelo; Benetti, Francine; Ferreira, Luciana Lousada; Rahal, Vanessa; Ervolino, Edilson; Jacinto, Rogério de Castilho; Gomes, João Eduardo; Briso, André Luiz Fraga

    2016-01-01

    ABSTRACT Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals (control) were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas. Conclusion The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents. PMID:27008262

  12. Evaluation of an experimental rat model for comparative studies of bleaching agents.

    PubMed

    Cintra, Luciano Tavares Angelo; Benetti, Francine; Ferreira, Luciana Louzada; Rahal, Vanessa; Ervolino, Edilson; Jacinto, Rogério de Castilho; Gomes Filho, João Eduardo; Briso, André Luiz Fraga

    2016-04-01

    Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats' vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the coronal pulp occlusal third up to the 15-min application groups of each bleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents.

  13. The Effects of Pyridaben Pesticide on the Histomorphometric, Hormonal Alternations and Reproductive Functions of BALB/c Mice

    PubMed Central

    Ebadi Manas, Ghodrat; Hasanzadeh, Shapour; Parivar, Kazem

    2013-01-01

    Objective(s): The adverse effects of pyridaben on reproductive system in male animals are not well established. This study was designed to elucidate how pyridaben can effects the histomorphometric, hormonal alternations and reproductive functions of BALB/c mice. Materials and Methods: For this study, 80 adult and apparently healthy male BALB/c mice were divided into three groups Viz, control, test group 1 and test group 2. Test groups 1 and 2 were received the toxin at doses of 53 mg/kg. BW, and 212 mg/kg. BW, respectively. The experiment period for both groups was 10, 25 and 45 days. Results: The levels of FSH, LH and testosterone were significantly (P<0.05) decreased on the dose and time dependant means. The levels of the ROS and NOS were significantly (P<0.05) increased in all test groups. The percent body weight gains significantly (P<0.05) reduced, whereas weights significantly (P<0.05) increased in test groups in a dose and time dependant manner. The histomorphometric and stereologic findings, including diameters of somniferous tubules, thickness of somniferous tubules epithelium, the leydig's cell distribution, TDI, SI, RI revealed that, all these parameters are also significantly (P<0.05) reduces in test groups in a dose and time dependant manner. Conclusion: Pyridaben causes histomorphometric and stereologic changes in testis, as well as hormonal and reproductive functional alternations in BALB/c mice. PMID:24379962

  14. Histomorphometric analysis of rat skeleton following spaceflight

    NASA Technical Reports Server (NTRS)

    Wronski, T. J.; Morey-Holton, E. R.; Doty, S. B.; Maese, A. C.; Walsh, C. C.

    1987-01-01

    Male Sprague-Dawley rats were placed in orbit for 7 days aboard the space shuttle. Bone histomorphometry was performed in the long bones and lumbar vertebrae of flight rats and compared with data derived from ground-based control rats. Trabecular bone mass was not altered during the 1st wk of weightlessness. Strong trends were observed in flight rats for decreased periosteal bone formation in the tibial diaphysis, reduced osteoblast size in the proximal tibia, and decreased osteoblast surface and number in the lumbar vertebra. For the most part, histological indexes of bone resorption were normal in flight rats. The results indicate that 7 days of weightlessness are not of sufficient duration to induce histologically detectable loss of trabecular bone in rats. However, cortical and trabecular bone formation appear to be diminished during the 1st wk of spaceflight.

  15. Evaluation of rhBMP-2 and natural latex as potential osteogenic proteins in critical size defects by histomorphometric methods.

    PubMed

    Issa, João Paulo Mardegan; Defino, Helton Luiz Aparecido; Netto, Joaquim Coutinho; Volpon, José Batista; Regalo, Simone Cecílio Hallak; Iyomasa, Mamie Mizusaki; Siéssere, Selma; Tiossi, Rodrigo

    2010-05-01

    This in vivo study evaluated the osteogenic potential of two proteins, recombinant human bone morphogenetic protein-2 (rhBMP-2) and a protein extracted from natural latex (Hevea brasiliensis, P-1), and compared their effects on bone defects when combined with a carrier or a collagen gelatin. Eighty-four (84) Wistar rats were divided into two groups, with and without the use of collagen gelatin, and each of these were divided into six treatment groups of seven animals each. The treatment groups were: (1) 5 microg of pure rhBMP-2; (2) 5 microg of rhBMP-2/monoolein gel; (3) pure monoolein gel; (4) 5 microg of pure P-1; (5) 5 microg of P-1/monoolein gel; (6) critical bone defect control. The animals were anesthetized and a 6 mm diameter critical bone defect was made in the left posterior region of the parietal bone. Animals were submitted to intracardiac perfusion after 4 weeks and the calvaria tissue was removed for histomorphometric analysis. In this experimental study, it was concluded that rhBMP-2 allowed greater new bone formation than P-1 protein and this process was more effective when the bone defect was covered with collagen gelatin (P < 0.05).

  16. Histomorphometric and biomechanical analyses of osseointegration of four different orthodontic mini implant surfaces

    NASA Astrophysics Data System (ADS)

    Yadav, Sumit

    Objective: To evaluate the osseointegration potential of four different surfaces of mini-implants. We hypothesized that mini-implants surface roughness alters the intrinsic biomechanical properties of the bone integrated to titanium. Materials and Methods: Mini implants and circular discs were made from alloy Ti6Al4V grade 5. On the basis of surface treatment study was divided into 4 groups: Group 1: Machined: no surface treatment, Group 2: Acid etched: with hydrochloric acid, Group 3: Grit Blasted with alumina and Group 4: Grit blasted +Acid etched. Surface roughness parameters (mean surface roughness: Ra and Quadratic Average roughness: Rq) of the four discs from each group were measured by the optical profilometer. Contact angle measurement of 3 discs from each group was done with a Goniometer. Contact angle of liquids with different hydrophobicity and hydrophilicity were measured. 128 mini implants, differing in surface treatment, were placed into the tibias and femurs of 8 adult male New Zealand white rabbits. Biomechanical properties (Removal torque and hardness) measurements and histomorphometric observations were measured. Results: Ra and Rq of groups were: Machined (1.17+/-0.11, 2.59+/-0.09) Acid etched (1.82+/-0.04, 3.17+/-0.13), Grit blasted (4.83+/-0.23, 7.04+/-0.08), Grit blasted + Acid etched (3.64+/-0.03, 4.95+/-0.04) respectively. Group 4 had significantly (p=0.000) lower Ra and Rq than Group 3. The interaction between the groups and liquid was significant. Group 4 had significantly lower contact angle measurements (40.4°, 26.9°), both for blood and NaCl when compared to other three groups (p≤0.01). Group 4 had significantly higher torque than Group 3 (Tibia: 13.67>9.07N-cm; Femur: 18.21>14.12N-cm), Group 4 (Tibia: 13.67>9.78N-cm; Femur: 18.21>12.87N-cm), and machined (Tibia: 13.67>4.08N-cm; Femur: 18.21>6.49N-cm). SEM analysis reveals significantly more bone implant gap in machined implant surfaces than treated implant surfaces. Bone to implant

  17. Effect of administration of retinol and etidronate on bone histomorphometric parameters in ovariectomized rats.

    PubMed

    Kaczmarczyk-Sedlak, Ilona; Pytlik, Maria; Sliwińiski, Leszek; Nowińska, Barbara; Juszczyk, Joanna

    2004-01-01

    Retinol belongs to factors affecting bone remodeling. The effect of retinol on the osseous tissue depends on the dose and duration of treatment. Retinol can cause bone damage and deformation. Retinol is frequently administered chronically in too high doses, sometimes by osteoporotic patients. The aim of the present study was to examine the interaction between retinol and an antiresorptive drug--disodium etidronate in bilaterally ovariectomized rats. The experiments were carried out on Wistar rats (200 +/- 30 g), divided into 7 groups: I--sham operated control rats. II--ovariectomized control rats (OVX), III--OVX + editronate (10 mg/kg p.o.), IV--OVX + retinol (700 IU/kg p.o.). V--OVX + retinol (3500) IU/kg p.o.), VI--OVX + etidronate (10 mg/kg p.o.) + retinol (700 IU/kg p.o.), VII--OVX + etidronate (10 mg/kg p.o.) + retinol (3500 IU/kg p.o.). The drugs were administered for 4 weeks. Bone macrometric and histomorphometric parameters of the tibia (transverse growth, width of periosteal and endosteal osteoid, area of the transverse cross-section of the diaphysis and area of the transverse cross-section of the marrow cavity) and the femur (width of epiphyseal and metaphyseal trabeculae, width of epiphyseal cartilage) were examined. Editronate partially counteracted the development of changes induced by ovariectomy. Retinol (700 IU/kg p.o.) caused decreases in the area of the transverse cross-section of the marrow cavity and the width of osteoid, and an increase in the width of trabeculae. Retinol (3500 IU/kg p.o.) caused decreases in bone mass and the area of the transverse corss-section of the marrow cavity, and an increase in the width of trabecula. Concurrent administration of etidronate and retinol in ovariectomized rats seemed not to affect bone histomorphometric parameters in a way suggesting any interaction between them.

  18. Multicolor holography: a comparative study

    NASA Astrophysics Data System (ADS)

    Oliveira, Rosa M.; Bernardo, Luis M.; Pinto, Joao L.

    2000-10-01

    A multicolor holography study case will be presented with emphasis on color control in different silver-halide materials. It has been systematized in order to compare the results obtained with Agfa 8E 75HD to those with Slavich PFG-01. Some experiments were made and the emulsion was manipulated before exposure to achieve high quality multicolored white light reflection holograms. This work has therefore been developed in order to obtain the various colors in a very well controlled way.

  19. [Comparative studies of face recognition].

    PubMed

    Kawai, Nobuyuki

    2012-07-01

    Every human being is proficient in face recognition. However, the reason for and the manner in which humans have attained such an ability remain unknown. These questions can be best answered-through comparative studies of face recognition in non-human animals. Studies in both primates and non-primates show that not only primates, but also non-primates possess the ability to extract information from their conspecifics and from human experimenters. Neural specialization for face recognition is shared with mammals in distant taxa, suggesting that face recognition evolved earlier than the emergence of mammals. A recent study indicated that a social insect, the golden paper wasp, can distinguish their conspecific faces, whereas a closely related species, which has a less complex social lifestyle with just one queen ruling a nest of underlings, did not show strong face recognition for their conspecifics. Social complexity and the need to differentiate between one another likely led humans to evolve their face recognition abilities.

  20. Genistein-induced histomorphometric and hormone secreting changes in the adrenal cortex in middle-aged rats.

    PubMed

    Ajdzanović, Vladimir; Sosić-Jurjević, Branka; Filipović, Branko; Trifunović, Svetlana; Manojlović-Stojanoski, Milica; Sekulić, Milka; Milosević, Verica

    2009-02-01

    The soybean phytoestrogen, genistein, is increasingly consumed as an alternative therapeutic for age-related diseases, namely cardiovascular conditions, cancer and osteoporosis. Besides estrogenic/antiestrogenic action, this isoflavone exerts a prominent inhibitory effect on tyrosine kinase and the steroidogenic enzyme families, thus affecting hormonal homeostasis. The aim of this study was to examine the effects of genistein on: histomorphometric features of the adrenal cortex, blood concentrations of aldosterone, corticosterone and dehydroepiandrosterone (DHEA) and adrenal tissue corticosterone content in orchidectomized middle-aged male rats. Sixteen-month-old Wistar rats were divided into sham-operated (SO), orchidectomized (Orx) and genistein-treated orchidectomized (Orx+G) groups. Genistein (30 mg/kg/day) was administered subcutaneously for three weeks, while the control groups received the vehicle alone. The adrenal cortex was analysed histologically and morphometrically. Circulating concentrations of aldosterone, corticosterone and DHEA, as well as adrenal tissue corticosterone levels, were determined by immunoassay. When compared to the SO group, orchidectomy decreased the ZG and ZR cell volume by 43% and 29%, respectively (P<0.05). Serum concentrations of aldosterone and DHEA were markedly lower [13% and 41%, respectively (P<0.05)], while serum and adrenal tissue levels of corticosterone did not change after orchidectomy. Orchidectomy followed by genistein treatment increased the ZG, ZF and ZR cell volume by 54%, 34% and 77%, respectively (P<0.05), compared to the untreated orchidectomized group. Histological analysis revealed noticeable vacuolization of the ZG and ZF cells in the Orx+G group. Serum aldosterone and corticosterone concentrations together with adrenal tissue corticosterone were 47%, 31% and 44% lower, respectively (P<0.05), whereas serum DHEA concentration was 342% higher (P<0.05) in this group in comparison with the Orx group. This study

  1. Aprotinin application has no negative effect on osseous implant integration: a biomechanical and histomorphometric investigation in a rat model.

    PubMed

    Faensen, B; Hain, C; Höhne, J; Schwabe, P; Haas, N; Schmidmaier, G; Wildemann, B

    2009-01-01

    Intraoperative blood loss requiring allogenic blood transfusion (ABT) is a common problem in major orthopedic surgery. Since transfusion related side effects up to fatal consequences due to blood type incompatibility cannot be excluded completely, it is desirable to reduce the amount of blood loss and transfusions to a minimum. Encouraging results in the application of aprotinin, a natural protease-inhibitor with antifibrinolytic, bleeding-reducing properties, in thoracic-, heart- and abdominal surgery led to the use of aprotinin also in orthopedic surgery. One important safety issue in the use of aprotinin in orthopedic surgery is a possible negative effect on the osseous integration of an implant due to the multiple interactions of aprotinin with several enzymatic systems. In this study, we therefore investigated the influence of aprotinin on the osseous ingrowth of a titanium-implant in a rat model. Forty female Sprague-Dawley rats underwent unilateral retrograde nailing of the femur. Animals were divided in two groups, one receiving i.v. aprotinin intraoperatively, the other group receiving the same amount as saline solution. After 56 days animals were killed and from each group half of the femora were prepared for biomechanical testing, the other half for histological examination. The push-out experiment revealed no significant difference between the aprotinin-group and the control-group, both showing comparable shear stresses. In addition, the histomorphometrical analysis showed comparable implant integration between both groups. The results demonstrate that perioperative aprotinin application has no negative effect on osseous implant integration in a rat model.

  2. Histomorphometric Assessment of Cancellous and Cortical Bone Material Distribution in the Proximal Humerus of Normal and Osteoporotic Individuals

    PubMed Central

    Sprecher, Christoph M.; Schmidutz, Florian; Helfen, Tobias; Richards, R. Geoff; Blauth, Michael; Milz, Stefan

    2015-01-01

    Abstract Osteoporosis is a systemic disorder predominantly affecting postmenopausal women but also men at an advanced age. Both genders may suffer from low-energy fractures of, for example, the proximal humerus when reduction of the bone stock or/and quality has occurred. The aim of the current study was to compare the amount of bone in typical fracture zones of the proximal humerus in osteoporotic and non-osteoporotic individuals. The amount of bone in the proximal humerus was determined histomorphometrically in frontal plane sections. The donor bones were allocated to normal and osteoporotic groups using the T-score from distal radius DXA measurements of the same extremities. The T-score evaluation was done according to WHO criteria. Regional thickness of the subchondral plate and the metaphyseal cortical bone were measured using interactive image analysis. At all measured locations the amount of cancellous bone was significantly lower in individuals from the osteoporotic group compared to the non-osteoporotic one. The osteoporotic group showed more significant differences between regions of the same bone than the non-osteoporotic group. In both groups the subchondral cancellous bone and the subchondral plate were least affected by bone loss. In contrast, the medial metaphyseal region in the osteoporotic group exhibited higher bone loss in comparison to the lateral side. This observation may explain prevailing fracture patterns, which frequently involve compression fractures and certainly has an influence on the stability of implants placed in this medial region. It should be considered when planning the anchoring of osteosynthesis materials in osteoporotic patients with fractures of the proximal humerus. PMID:26705200

  3. Sex work: a comparative study.

    PubMed

    McCarthy, Bill; Benoit, Cecilia; Jansson, Mikael

    2014-10-01

    Explanations of adult involvement in sex work typically adopt one of two approaches. One perspective highlights a variety of negative experiences in childhood and adolescence, including physical and sexual abuse, family instability, poverty, associations with "pimps" and other exploiters, homelessness, and drug use. An alternative account recognizes that some of these factors may be involved, but underscores the contribution of more immediate circumstances, such as current economic needs, human capital, and employment opportunities. Prior research offers a limited assessment of these contrasting claims: most studies have focused exclusively on people working in the sex industry and they have not assessed the independent effects of life course variables central to these two perspectives. We add to this literature with an analysis that drew on insights from life course and life-span development theories and considered the contributions of factors from childhood, adolescence, and adulthood. Our comparative approach examined predictors of employment in sex work relative to two other low-income service or care work occupations: food and beverage serving and barbering and hairstyling. Using data from a study of almost 600 workers from two cities, one in Canada and the other in the United States, we found that both immediate circumstances and negative experiences from early life are related to current sex work involvement: childhood poverty, abuse, and family instability were independently associated with adult sex work, as were limited education and employment experience, adult drug use, and marital status.

  4. Static histomorphometry of human iliac crest and vertebral trabecular bone: a comparative study.

    PubMed

    Thomsen, J S; Ebbesen, E N; Mosekilde, Li

    2002-01-01

    We recently developed a new, rapid method for conducting static histomorphometry on large histologic sections. This method has now been applied on both iliac crest and lumbar vertebral bone to compare the age-related changes at these two skeletal sites and to investigate the correlation between the histomorphometric measures at the iliac crest and the vertebral body. The material comprised matched sets of unilateral transiliac crest bone biopsies and lumbar vertebral bodies (L-2) from 24 women (19-96 years) and 24 men (23-95 years) selected from a larger autopsy material. Three female subjects (80, 88, and 90 years) had a known vertebral fracture of L-2. The iliac crest biopsies and 9-mm-thick mediolateral slices of half the entire vertebral bodies were embedded in methylmetacrylate, stained with aniline blue, and scanned into a computer with a flatbed image scanner at a high resolution. With a custom-made computer program the following static histomorphometric measures were determined: trabecular bone volume; marrow and bone space star volume; node-strut analysis; trabecular bone pattern factor; trabecular thickness; trabecular number; trabecular separation; and anisotropy of bone and marrow phase. In addition, connectivity density was measured (ConnEulor method). The results showed that the age-related changes in the static histomorphometric measures are generally similar in the iliac crest and the vertebral body, and that these age-related changes are independent of gender. An exception, however, is connectivity density, where the age-related changes are similar for women and men in the vertebral body but significantly different in the iliac crest. Furthermore, the results showed that the histomorphometric measures were weakly intercorrelated between the iliac crest and the vertebral body, despite the generally similar pattern in age-related changes at these two skeletal sites. The highest correlation coefficient was found for trabecular separation (Tb.Sp; r = 0

  5. Wound healing following regenerative procedures in furcation degree III defects: histomorphometric outcomes.

    PubMed

    Gkranias, Nikolaos D; Graziani, Filippo; Sculean, Anton; Donos, Nikolaos

    2012-02-01

    Degree III furcation involvements were surgically created at four first molars in each of three monkeys. Following 6 weeks of healing, full-thickness flaps were elevated. Following 24% EDTA gel conditioning, the defects were treated with one of the following: (1) enamel matrix proteins (EMD), (2) guided tissue regeneration (GTR) or (3) a combination EMD and GTR. The control defects did not receive any treatment. After 5 months of healing, the animals were sacrificed. Three 8 μm thick histological central sections, 100 μm apart, were used for histomorphometric analysis in six zones of each tooth either within the furcation area or on the pristine external surface of the root. In all specimens, new cementum with inserting collagen fibres was formed. Following GTR or GTR + EMD, cementum was formed up to and including the furcation fornix indicating complete regeneration on the defect periphery. Periodontal ligament fibres were less in all four modalities compared to pristine tissues. In the teeth treated with GTR and GTR + EMD a higher volume of bone and periodontal ligament tissues was observed compared to EMD. After 5 months of healing, regenerated tissues presented quantitative differences from the pristine tissues. In the two modalities where GTR alone or combined with EMD was used, the regenerated tissues differed in quantity from the EMD-treated sites.

  6. The efficacy of the use of IR laser phototherapy associated to biphasic ceramic graft and guided bone regeneration on surgical fractures treated with miniplates: a histological and histomorphometric study on rabbits.

    PubMed

    Pinheiro, Antonio L B; Aciole, Gilberth Tadeu Santos; Ramos, Thais Andrade; Gonzalez, Tayná Assunção; da Silva, Laís Nogueira; Soares, Luiz G Pinheiro; Aciole, Jouber Mateus Santos; dos Santos, Jean Nunes

    2014-01-01

    The aim of the present study was to assess, by light microscopy and histomorphometry, the repair of surgical fractures fixed with internal rigid fixation (IRF) treated or not with IR laser (λ780 nm, 50 mW, 4 × 4 J/cm(2) = 16 J/cm(2), ϕ = 0.5 cm(2), CW) associated or not to the use of hydroxyapatite and guided bone regeneration. Surgical tibial fractures were created under general anesthesia on 15 rabbits that were divided into 5 groups, maintained on individual cages, at day/night cycle, fed with solid laboratory pelted diet, and had water ad libidum. The fractures in groups II, III, IV, and V were fixed with miniplates. Animals in groups III and V were grafted with hydroxyapatite and GBR technique used. Animals in groups IV and V were irradiated at every other day during two weeks (4 × 4 J/cm(2), 16 J/cm(2) = 112 J/cm(2)). Observation time was that of 30 days. After animal death, specimens were taken, routinely processed to wax, cut and stained with HA and Sirius red, and used for histological assessment. The results of both analyses showed a better bone repair on all irradiated subjects especially when the biomaterial and GBR were used. In conclusion, the results of the present investigation are important clinically as they are suggestive that the association of hydroxyapatite, and laser light resulted in a positive and significant repair of complete tibial fractures treated with miniplates.

  7. Histomorphometric and ultrastructural analysis of the tendon-bone interface after rotator cuff repair in a rat model

    PubMed Central

    Kanazawa, Tomonoshin; Gotoh, Masafumi; Ohta, Keisuke; Honda, Hirokazu; Ohzono, Hiroki; Shimokobe, Hisao; Shiba, Naoto; Nakamura, Kei-ichiro

    2016-01-01

    Successful rotator cuff repair requires biological anchoring of the repaired tendon to the bone. However, the histological structure of the repaired tendon-bone interface differs from that of a normal tendon insertion. We analysed differences between the normal tendon insertion and the repaired tendon-bone interface after surgery in the mechanical properties, histomorphometric analysis, and 3-dimensional ultrastructure of the cells using a rat rotator cuff repair model. Twenty-four adult Sprague-Dawley (SD) rats underwent complete cuff tear and subsequent repair of the supraspinatus tendon. The repaired tendon-bone interface was evaluated at 4, 8, and 12 weeks after surgery. At each time point, shoulders underwent micro-computed tomography scanning and biomechanical testing (N = 6), conventional histology and histomorphometric analysis (N = 6), and ultrastructural analysis with focused ion beam/scanning electron microscope (FIB/SEM) tomography (N = 4). We demonstrated that the cellular distribution between the repaired tendon and bone at 12 weeks after surgery bore similarities to the normal tendon insertion. However, the ultrastructure of the cells at any time point had a different morphology than those of the normal tendon insertion. These morphological differences affect the healing process, partly contributing to re-tearing at the repair site. These results may facilitate future studies of the regeneration of a normal tendon insertion. PMID:27647121

  8. Comparative Studies in Special Education.

    ERIC Educational Resources Information Center

    Mazurek, Kas, Ed.; Winzer, Margret A., Ed.

    This text presents 26 case studies which examine special education provisions for children in the world today. The reports focus on the current state of special education in selected nations and major issues and controversies in the field of special education within those nations. Each case study addresses the following themes: (1) prevalence of…

  9. Comparative study of silicon detectors

    SciTech Connect

    Allier, C.P.; Valk, H.; Huizenga, J.; Bom, V.R.; Hollander, R.W.; Eijk, C.W.E. van

    1998-06-01

    The authors studied three different types of silicon sensors: PIN diodes, circular drift detectors, both made at the Delft University of Technology (DUT), and Hamamatsu S5345 avalanche photodiodes. Measurements have been carried out in the same optimized experimental setup, both at room temperature and at low temperatures. Comparison is made for direct X-ray detection and CsI(Tl) scintillation light readout.

  10. Variation in osteon histomorphometrics and their impact on age-at-death estimation in older individuals.

    PubMed

    Goliath, Jesse R; Stewart, Marissa C; Stout, Sam D

    2016-05-01

    Histomorphometric studies have reported relations between osteon size and age; however, data focused on the shape of osteons is sparse. The purpose of this study was to determine how osteon circularity (On.Cr) varies with age in different skeletal elements. Regression analysis was used to evaluate the relationship between age and osteon shape and size. We hypothesized that age would be negatively related to osteon size (area, On.Ar) and positively related to osteon shape (On.Cr). On.Cr and On.Ar were determined for the ribs and femora of 27 cadaveric specimens with known age-at-death. As predicted, age was significantly related to osteon size and shape for both the femur and rib. With age, there was a decrease in size and an increase in circularity. No relationship between sex and On.Cr was detected. An age predicting model, including On.Cr, On.Ar and OPD, is proposed to improve our ability to estimate age-at-death, especially for older individuals.

  11. Histomorphometric analysis of the irides of dogs, camels, buffalos and donkeys.

    PubMed

    Aly, Khaled H; Abd-Elhafez, Enas; Ali, Mona; Abd-Elmaksoud, Ahmed

    2009-02-01

    The present study was carried out to investigate the morphological and histomorphometrical characters of irides in dogs, camels, buffalos, and donkeys. The findings of the study revealed that, morphologically, the irides were consisted of an anterior border layer, a middle layer of connective tissue stroma and a posterior layer of pigmented epithelium. Interestingly, the anterior borders of all investigated animals were not enveloped by a distinct epithelial or endothelial lining, but on contrary, the posterior border was covered by pigmented epithelium. The constrictor and dilator iridial muscles were well developed in dogs, weakly developed in donkeys, and with an intermediate position in camels and buffalos. Morphometric analysis revealed significant species differences in the mean total thickness of the iris and its different layers. In addition significant differences were also found between the ratio of the means of different layers to the total thickness of the iris at the pupillary, middle and ciliary borders. In conclusion, these variations might be related to the different lifestyles and visual behaviour of the investigated animals.

  12. Histomorphometric and microchemical characterization of maturing dental enamel in rats fed a boron-deficient diet.

    PubMed

    Haro Durand, Luis A; Mesones, Rosa Vera; Nielsen, Forrest H; Gorustovich, Alejandro A

    2010-06-01

    Few reports are available in the literature on enamel formation under nutritional deficiencies. Thus, we performed a study to determine the effects of boron (B) deficiency on the maturing dental enamel, employing the rat continuously erupting incisor as the experimental model. Male Wistar rats, 21 days old, were used throughout. They were divided into two groups, each containing ten animals: +B (adequate; 3-mg B/kg diet) and -B (boron deficient; 0.07-mg B/kg diet). The animals were maintained on their respective diets for 14 days and then euthanized. The mandibles were resected, fixed, and processed for embedding in paraffin and/or methyl methacrylate. Oriented histological sections of the continuously erupting incisor were obtained at the level of the mesial root of the first molar, allowing access to the maturation zone of the developing enamel. Dietary treatment did not affect food intake and body weight. Histomorphometric evaluation using undecalcified sections showed a reduction in enamel thickness (hypoplasia), whereas microchemical characterization by energy-dispersive X-ray spectrometry did not reveal alterations in enamel mineralization.

  13. Comparative pyrolysis studies of ethylarsines

    NASA Astrophysics Data System (ADS)

    Li, S. H.; Larsen, C. A.; Stringfellow, G. B.

    1991-01-01

    The pyrolysis of triethylarsine (TEAs), diethylarsine (DEAsH), and monoethylarsine (MEAsH 2) has been studied at atmospheric pressure in a flow tube reactor using mass spectrometry. He and D 2 were selected as the carrier gases to determine ambient effects and to isotopically label the pyrolysis products. For some experiments, supplemental C 2H 5 and CH 3 radicals, produced from pyrolysis of the co-reactants azoethane ((C 2H 5) 2N 2) and azomethane ((CH 3) 2N 2), were added to investigate the roles of C 2H 5 and CH 3 in the reactions. Significant D 2 effects have been observed for pyrolysis of TEAs but not for DEAsH and MEAsH 2. Pyrolysis of the latter could be enhanced by adding C 2H 5 radicals while the TEAs was nearly unaffected. With the presence of supplemental CH 3 radicals, 85% decomposition was induced for each precursor. The products included DEAsD, rather than DEAsH, for TEAs pyrolysis in D 2. However, DEAsH pyrolysis produced TEAs, and MEAsH 2 decomposed to yield DEAsH and arsine, in both ambients. This suggests that a β-elimination reaction is not a major step for any of the ethylarsine precursors. More likely, radical reactions occur. When trimethylgallium (TMGa) was added, the ethylarsine pyrolysis rates were accelerated due to the CH 3 radicals produced from TMGa pyrolysis. In addition, heterogeneous reactions have been observed for pyrolysis of ethylarsines, especially when a GaAs surface was involved.

  14. Histologic and histomorphometric evaluation of two grafting materials Cenobone and ITB-MBA in open sinus lift surgery

    PubMed Central

    Amoian, Babak; Seyedmajidi, Maryam; Safipor, Hamidreza; Ebrahimipour, Sediqe

    2016-01-01

    Aims and Objectives: Alveolar ridge reduction caused after tooth extraction can be minimized through ridge preservation and application of graft materials. The aim of this study was to compare the histologic and histomorphometric aspects of bone particulated allografts, Cenobone and ITB-MBA, in the reconstruction of vertical alveolar ridge after maxillary sinus augmentation. Materials and Methods: This clinical trial was performed among 20 patients. The participants were randomly divided into two groups of 10 participants. The first group received Cenobone and the second group received ITB-MBA. Tissue samples were prepared 6 months later at the time of implant installation and after successful maxillary sinus floor augmentation. Tissue sections were examined under a light microscope. The data were analyzed by Chi-square and t-test. Results: The mean trabecular thickness of the samples in the Cenobone group was 13.61 ± 7.47 μm compared to 13.73 ± 7.37 μm in the ITB-MBA group (P = 0.93). A mild inflammation process (Grade 1) was detected in both the groups. The amount of remaining biomaterial in the Cenobone group was estimated to be 8 ± 19% vs. 7 ± 12% in the ITB-MBA group (P = 0.30). Bone formation was reported 49.71% in the Cenobone group vs. 40.76% in the ITB-MBA group (P = 0.68). The mean newly formed vessel in the Cenobone group was 0.64 ± 0.7 vs. 1.5 ± 2.3 in the ITB-MBA group (P = 0.14). Conclusions: There was no significant difference between the two groups of patients regarding trabecular thickness, remaining biomaterial allograft, and the density of blood vessels after sinus floor elevation; hence, there was no difference between the two groups regarding implant outcome. More designed studies as randomized controlled trials and controlled clinical trials, which evaluate the long-term implant outcome; comparing the different bone graft materials is also required to improve evidence on survival and success rate. PMID:27891316

  15. Mechanical removal of necrotic periodontal ligament by either Robinson bristle brush with pumice or scalpel blade. Histomorphometric analysis and scanning electron microscopy.

    PubMed

    Esper, Helen Ramon; Panzarini, Sônia Regina; Poi, Wilson Roberto; Sonoda, Celso Koogi; Casatti, Cláudio Aparecido

    2007-12-01

    One of the important factors accounting for successful delayed replantation of avulsed teeth is seemingly the type of root surface treatment. Removal of necrotic cemental periodontal ligament remnants may prevent the occurrence of external root resorption, which is the major cause of loss of teeth replanted in such conditions. The purpose of this study was to compare the efficacy of two mechanical techniques for removal of root-adhered periodontal ligament. Preservation or removal of the cementum layer concomitantly with these procedures was also assessed. Forty-five roots of healthy premolars extracted for orthodontic purposes were selected. After extraction, the teeth were kept dry at room temperature for 1 h and then immersed in saline for rehydration for an additional 10 min. Thereafter, the roots were assigned to three groups, as follows: group 1 (control)--the cemental periodontal ligament was preserved; group 2--removal of the periodontal ligament by scraping root surface with a scalpel blade (SBS); group 3--periodontal ligament remnants were removed using a Robinson bristle brush at low-speed with pumice/water slurry (RBP). The specimens were analysed histomorphometrically and examined by scanning electron microscopy. The quantitative and qualitative analyses of the results showed that the RBP technique was significantly more effective than the SBS technique for removal of the periodontal ligament remnants adhered to root surface. Both techniques preserved the cementum layer.

  16. Histological and histomorphometrical analysis of a silica matrix embedded nanocrystalline hydroxyapatite bone substitute using the subcutaneous implantation model in Wistar rats.

    PubMed

    Ghanaati, Shahram; Orth, Carina; Barbeck, Mike; Willershausen, Ines; Thimm, Benjamin W; Booms, Patrick; Stübinger, Stefan; Landes, Constantin; Sader, Robert Anton; Kirkpatrick, Charles James

    2010-06-01

    The clinical suitability of a bone substitute material is determined by the ability to induce a tissue reaction specific to its composition. The aim of this in vivo study was to analyze the tissue reaction to a silica matrix-embedded, nanocrystalline hydroxyapatite bone substitute.The subcutaneous implantation model in Wistar rats was chosen to assess the effect of silica degradation on the vascularization of the biomaterial and its biodegradation within a time period of 6 months. Already at day 10 after implantation, histomorphometrical analysis showed that the vascularization of the implantation bed reached its peak value compared to all other time points. Both vessel density and vascularization significantly decreased until day 90 after implantation. In this time period, the bone substitute underwent a significant degradation initiated by TRAP-positive and TRAP-negative multinucleated giant cells together with macrophages and lymphocytes. Although no specific tissue reaction could be related to the described silica degradation, the biomaterial was close to being fully degraded without a severe inflammatory response. These characteristics are advantageous for bone regeneration and remodeling processes.

  17. Effect of Sodium Fluoride on Bone Biomechanical and Histomorphometric Parameters and on Insulin Signaling and Insulin Sensitivity in Ovariectomized Rats.

    PubMed

    de Cássia Alves Nunes, Rita; Chiba, Fernando Yamamoto; Pereira, Amanda Gomes; Pereira, Renato Felipe; de Lima Coutinho Mattera, Maria Sara; Ervolino, Edilson; Louzada, Mário Jefferson Quirino; Buzalaf, Marília Afonso Rabelo; Silva, Cristina Antoniali; Sumida, Doris Hissako

    2016-09-01

    Osteoporosis is a systemic disease characterized by bone degradation and decreased bone mass that promotes increased bone fragility and eventual fracture risk. Studies have investigated the use of sodium fluoride (NaF) for the treatment of osteoporosis. However, fluoride can alter glucose homeostasis. The aim of this study was to evaluate the effects of NaF intake (50 mg/L) from water on the following parameters of ovariectomized (OVX) rats: (1) tyrosine phosphorylation status of insulin receptor substrate (pp185 (IRS-1/IRS-2)) in white adipose tissue; (2) insulin sensitivity; (3) plasma concentrations of glucose, insulin, total cholesterol, triglyceride, TNF-α, IL-6, osteocalcin, calcium, and fluoride; (4) bone density and biomechanical properties in the tibia; and (5) tibia histomorphometric analysis. Fifty-two Wistar rats (2 months old) were ovariectomized and distributed into two groups: control group (OVX-C) and NaF group (OVX-F), which was subjected to treatment with NaF (50 mg/L) administered in drinking water for 42 days. The chronic treatment with NaF promoted (1) a decrease in pp185 (IRS-1/IRS-2) tyrosine phosphorylation status after insulin infusion in white adipose tissue and in insulin sensitivity; (2) an increase in the plasma concentration of insulin, fluoride, osteocalcin, calcium, triglyceride, VLDL-cholesterol, TNF-α, and IL-6; (3) a reduction in the trabecular width, bone area, stiffness, maximum strength, and tenacity; (4) no changes in body weight, food and water intake, plasma glucose, total cholesterol, HDL-cholesterol, LDL-cholesterol, bone mineral content, and bone mineral density. It was concluded that chronic treatment with NaF (50 mg/L) in OVX rats causes a decrease in insulin sensitivity, insulin signaling transduction, and biochemical, biomechanical, and histomorphometric bone parameters.

  18. Ovariectomy hinders the early stage of bone-implant integration: histomorphometric, biomechanical, and molecular analyses.

    PubMed

    Ozawa, S; Ogawa, T; Iida, K; Sukotjo, C; Hasegawa, H; Nishimura, R D; Nishimura, I

    2002-01-01

    Postmenopausal osteoporosis is a contributing factor to alveolar bone atrophy associated with tooth loss in the elderly. The use of dental titanium implants has been increasingly adapted to treat these edentulous patients. This study examines whether female gonadal hormone deficiency interferes with the critical integration process between bone and implants. Two types of experimental titanium implants with acid-treated surfaces were placed in the femurs of ovariectomized (ovx) and sham-operated control rats: T-cell implants with a hollow chamber for histomorphometric and steady-state mRNA expression assays, and unthreaded cylindrical implants for biomechanical push-in tests. At week 2, less bone area was found in the ovx-implant group (p = 0.0495) than in the sham-implant group. The implant push-in test showed that the ovx-implant group had approximately half of the withstanding value of the sham-implant group (p = 0.009). However, these differences between the ovx and sham groups became diminished at week 4. Total RNA samples were examined by a reverse transcriptase-polymerase chain reaction assay for col1a1, col3a1, bone sialoprotein (bSP) II, osteonectin, osteopontin, osteocalcin, integrin beta1 and integrin beta3. In untreated bones and in created bone defects without implant placement, ovx did not affect the steady-state levels of the mRNAs tested. When implants were placed, significant upregulation of these genes was observed in the sham-implant group; however, only osteocalcin and integrins were upregulated in the ovx-implant group. The results suggest a biphasic effect of female gonadal hormone deficiency that may temporarily interfere with the early implant-tissue integration process, and which may be associated with a failure to upregulate a selected set of bone extracellular matrix genes. Once established, however, functional bone-implant integration can be achieved even in ovx rats.

  19. Inner architecture of vertebral centra in terrestrial and aquatic mammals: a two-dimensional comparative study.

    PubMed

    Dumont, Maitena; Laurin, Michel; Jacques, Florian; Pellé, Eric; Dabin, Willy; de Buffrénil, Vivian

    2013-05-01

    Inner vertebral architecture is poorly known, except in human and laboratory animals. In order to document this topic at a broad comparative level, a 2D-histomorphometric study of vertebral centra was conducted in a sample of 98 therian mammal species, spanning most of the size range and representing the main locomotor adaptations known in therian taxa. Eleven variables relative to the development and geometry of trabecular networks were extracted from CT scan mid-sagittal sections. Phylogeny-informed statistical tests were used to reveal the respective influences of phylogeny, size, and locomotion adaptations on mammalian vertebral structure. The use of random taxon reshuffling and squared change parsimony reveals that 9 of the 11 characteristics (the two exceptions are total sectional area and structural polarization) contain a phylogenetic signal. Linear discriminant analyses suggest that the sampled taxa can be arranged into three categories with respect to locomotion mode: a) terrestrial + flying + digging + amphibious forms, b) coastal oscillatory aquatic taxa, and c) pelagic oscillatory aquatic forms represented by oceanic cetaceans. Pairwise comparison tests and linear regressions show that, when specific size increases, the length of trabecular network (Tt.Tb.Le), as well as trabecular proliferation in total sections (Pr.Tb.Tt), increase with positive allometry. This process occurs in all locomotion categories but is particularly pronounced in pelagic oscillators. Conversely, mean trabecular width has a lesser increase with size in pelagic oscillators. Trabecular orientation is not influenced by size. All tests were corrected for multiple testing. By using six structural variables or indices, locomotion mode can be predicted with a 97.4% success rate for terrestrial forms, 66.7% for coastal oscillatory, and 81.3% for pelagic oscillatory. The possible functional meaning of these results and their potential use for paleobiological inference of locomotion in

  20. Clinical application of bisphosphonates in implant dentistry: histomorphometric evaluation.

    PubMed

    Zuffetti, Francesco; Bianchi, Francesca; Volpi, Raffaele; Trisi, Paolo; Del Fabbro, Massimo; Capelli, Matteo; Galli, Fabio; Capsoni, Franco; Testori, Tiziano

    2009-02-01

    Bisphosphonates are pharmacologic compounds characterized by high tropism to bone tissue. They affect bone metabolism by inhibition of osteoclast recruitment, proliferation, differentiation, and function. Because they can reduce bone resorption, bisphosphonates are used mainly for the treatment of osteometabolic conditions, particularly osteoporosis, Paget disease, multiple myeloma, and other solid tumors with bone metastases. Their use has conferred great benefits to patients affected by these diseases, significantly improving their quality of life. Bisphosponates' inhibition of bone resorption might be exploited to maintain implant primary stability during the process of implant osseointegration. The aim of this histologic clinical study was to compare the response of bone tissue around an implant treated with a bisphosphonate solution (test) to that of the bone around an untreated implant (control). The bisphosphonate-treated implant showed more contact with newly formed bone than the control implant.

  1. Comparative Environmental Threat Analysis: Three Case Studies.

    ERIC Educational Resources Information Center

    Latour, J. B.; Reiling, R.

    1994-01-01

    Reviews how carrying capacity for different environmental problems is operationalized. Discusses whether it is possible to compare threats, using the exceeding of carrying capacity as a yardstick. Points out problems in comparative threat analysis using three case studies: threats to European groundwater resources, threats to ecosystems in Europe,…

  2. Comparative Review of Elementary Social Studies Textbooks.

    ERIC Educational Resources Information Center

    Waters, Barbara A.

    Four elementary social studies textbook series are reviewed and compared with particular attention paid to the extent to which the textbooks are globally oriented. The trend of emphasizing global education in the social studies also is discussed. As used in this paper, "global education" includes the study of world geography, world…

  3. Comparative studies of gene regulatory mechanisms.

    PubMed

    Pai, Athma A; Gilad, Yoav

    2014-12-01

    It has become increasingly clear that changes in gene regulation have played an important role in adaptive evolution both between and within species. Over the past five years, comparative studies have moved beyond simple characterizations of differences in gene expression levels within and between species to studying variation in regulatory mechanisms. We still know relatively little about the precise chain of events that lead to most regulatory adaptations, but we have taken significant steps towards understanding the relative importance of changes in different mechanisms of gene regulatory evolution. In this review, we first discuss insights from comparative studies in model organisms, where the available experimental toolkit is extensive. We then focus on a few recent comparative studies in primates, where the limited feasibility of experimental manipulation dictates the approaches that can be used to study gene regulatory evolution.

  4. Comparative Study Of Four Models Of Turbulence

    NASA Technical Reports Server (NTRS)

    Menter, Florian R.

    1996-01-01

    Report presents comparative study of four popular eddy-viscosity models of turbulence. Computations reported for three different adverse pressure-gradient flowfields. Detailed comparison of numerical results and experimental data given. Following models tested: Baldwin-Lomax, Johnson-King, Baldwin-Barth, and Wilcox.

  5. The Student Teaching Experience: A Comparative Study.

    ERIC Educational Resources Information Center

    Butler, Judy D.

    This paper describes a 1996 study that compared the student teaching experiences of a traditional and a nontraditional student to ascertain what differences in their experiences might imply about teacher preparation. The two students kept journals that could be written in at any time of the day. They recorded their impressions of their situation…

  6. Intramembranous bone healing process subsequent to tooth extraction in mice: micro-computed tomography, histomorphometric and molecular characterization.

    PubMed

    Vieira, Andreia Espindola; Repeke, Carlos Eduardo; Ferreira Junior, Samuel de Barros; Colavite, Priscila Maria; Biguetti, Claudia Cristina; Oliveira, Rodrigo Cardoso; Assis, Gerson Francisco; Taga, Rumio; Trombone, Ana Paula Favaro; Garlet, Gustavo Pompermaier

    2015-01-01

    Bone tissue has a significant potential for healing, which involves a significant the interplay between bone and immune cells. While fracture healing represents a useful model to investigate endochondral bone healing, intramembranous bone healing models are yet to be developed and characterized. In this study, a micro-computed tomography, histomorphometric and molecular (RealTimePCRarray) characterization of post tooth-extraction alveolar bone healing was performed on C57Bl/6 WT mice. After the initial clot dominance (0 h), the development of a provisional immature granulation tissue is evident (7 d), characterized by marked cell proliferation, angiogenesis and inflammatory cells infiltration; associated with peaks of growth factors (BMP-2-4-7,TGFβ1,VEGFa), cytokines (TNFα, IL-10), chemokines & receptors (CXCL12, CCL25, CCR5, CXCR4), matrix (Col1a1-2, ITGA4, VTN, MMP1a) and MSCs (CD105, CD106, OCT4, NANOG, CD34, CD146) markers expression. Granulation tissue is sequentially replaced by more mature connective tissue (14 d), characterized by inflammatory infiltrate reduction along the increased bone formation, marked expression of matrix remodeling enzymes (MMP-2-9), bone formation/maturation (RUNX2, ALP, DMP1, PHEX, SOST) markers, and chemokines & receptors associated with healing (CCL2, CCL17, CCR2). No evidences of cartilage cells or tissue were observed, strengthening the intramembranous nature of bone healing. Bone microarchitecture analysis supports the evolving healing, with total tissue and bone volumes as trabecular number and thickness showing a progressive increase over time. The extraction socket healing process is considered complete (21 d) when the dental socket is filled by trabeculae bone with well-defined medullary canals; it being the expression of mature bone markers prevalent at this period. Our data confirms the intramembranous bone healing nature of the model used, revealing parallels between the gene expression profile and the

  7. Intramembranous Bone Healing Process Subsequent to Tooth Extraction in Mice: Micro-Computed Tomography, Histomorphometric and Molecular Characterization

    PubMed Central

    Vieira, Andreia Espindola; Repeke, Carlos Eduardo; Ferreira Junior, Samuel de Barros; Colavite, Priscila Maria; Biguetti, Claudia Cristina; Oliveira, Rodrigo Cardoso; Assis, Gerson Francisco; Taga, Rumio; Trombone, Ana Paula Favaro; Garlet, Gustavo Pompermaier

    2015-01-01

    Bone tissue has a significant potential for healing, which involves a significant the interplay between bone and immune cells. While fracture healing represents a useful model to investigate endochondral bone healing, intramembranous bone healing models are yet to be developed and characterized. In this study, a micro-computed tomography, histomorphometric and molecular (RealTimePCRarray) characterization of post tooth-extraction alveolar bone healing was performed on C57Bl/6 WT mice. After the initial clot dominance (0h), the development of a provisional immature granulation tissue is evident (7d), characterized by marked cell proliferation, angiogenesis and inflammatory cells infiltration; associated with peaks of growth factors (BMP-2-4-7,TGFβ1,VEGFa), cytokines (TNFα, IL-10), chemokines & receptors (CXCL12, CCL25, CCR5, CXCR4), matrix (Col1a1-2, ITGA4, VTN, MMP1a) and MSCs (CD105, CD106, OCT4, NANOG, CD34, CD146) markers expression. Granulation tissue is sequentially replaced by more mature connective tissue (14d), characterized by inflammatory infiltrate reduction along the increased bone formation, marked expression of matrix remodeling enzymes (MMP-2-9), bone formation/maturation (RUNX2, ALP, DMP1, PHEX, SOST) markers, and chemokines & receptors associated with healing (CCL2, CCL17, CCR2). No evidences of cartilage cells or tissue were observed, strengthening the intramembranous nature of bone healing. Bone microarchitecture analysis supports the evolving healing, with total tissue and bone volumes as trabecular number and thickness showing a progressive increase over time. The extraction socket healing process is considered complete (21d) when the dental socket is filled by trabeculae bone with well-defined medullary canals; it being the expression of mature bone markers prevalent at this period. Our data confirms the intramembranous bone healing nature of the model used, revealing parallels between the gene expression profile and the histomorphometric

  8. Effects of Spirulina on Cyclophosphamide-Induced Ovarian Toxicity in Rats: Biochemical and Histomorphometric Evaluation of the Ovary

    PubMed Central

    Yener, Nese Arzu; Sinanoglu, Orhun; Ilter, Erdin; Celik, Aygen; Sezgin, Gulbuz; Midi, Ahmet; Aksungar, Fehime

    2013-01-01

    Cyclophosphamide (Cyc) is known to cause ovotoxicity and infertility in women. Our aim is to investigate the possible ovotoxic effects of Cyc and possible antioxidant and protective effects of blue-green algae, Spirulina (Sp), in rat ovaries. Eighteen rats were given: group I (n = 6, control); group II (n = 6, CP), a single dose Cyc; group III (n = 6, Sp+Cyc), 7 days Sp+single dose Cyc. Tissue malondialdehyde (MDA) levels, superoxide dismutase (SOD), and catalase (CAT) activities are assessed biochemically. Normal and atretic primordial and primary follicle counts for all sections obtained for each ovary are calculated. Mean number of follicle counts for each group are compared. In Sp+Cyc group, tissue MDA levels were significantly lower than those in the CP and higher than those in the C group (CP > Sp+Cyc > C). Tissue SOD activity was significantly higher in Sp+Cyc group than that in the CP group and lower than that in the C group (C > Sp+Cyc > C). No statistically significant difference was found between the ovarian CAT activities in any group. Histomorphometrically, there was also no significant difference between the mean numbers of normal and atretic small follicle counts. Our results suggest that single dose Cyc has adverse effects on oxidant status of the ovaries and Sp has protective effects in Cyc-induced ovotoxicity. PMID:23762559

  9. Evaluating stability of histomorphometric features across scanner and staining variations: predicting biochemical recurrence from prostate cancer whole slide images

    NASA Astrophysics Data System (ADS)

    Leo, Patrick; Lee, George; Madabhushi, Anant

    2016-03-01

    Quantitative histomorphometry (QH) is the process of computerized extraction of features from digitized tissue slide images. Typically these features are used in machine learning classifiers to predict disease presence, behavior and outcome. Successful robust classifiers require features that both discriminate between classes of interest and are stable across data from multiple sites. Feature stability may be compromised by variation in slide staining and scanning procedures. These laboratory specific variables include dye batch, slice thickness and the whole slide scanner used to digitize the slide. The key therefore is to be able to identify features that are not only discriminating between the classes of interest (e.g. cancer and non-cancer or biochemical recurrence and non- recurrence) but also features that will not wildly fluctuate on slides representing the same tissue class but from across multiple different labs and sites. While there has been some recent efforts at understanding feature stability in the context of radiomics applications (i.e. feature analysis of radiographic images), relatively few attempts have been made at studying the trade-off between feature stability and discriminability for histomorphometric and digital pathology applications. In this paper we present two new measures, preparation-induced instability score (PI) and latent instability score (LI), to quantify feature instability across and within datasets. Dividing PI by LI yields a ratio for how often a feature for a specific tissue class (e.g. low grade prostate cancer) is different between datasets from different sites versus what would be expected from random chance alone. Using this ratio we seek to quantify feature vulnerability to variations in slide preparation and digitization. Since our goal is to identify stable QH features we evaluate these features for their stability and thus inclusion in machine learning based classifiers in a use case involving prostate cancer

  10. 3D histomorphometric quantification of trabecular bones by computed microtomography using synchrotron radiation.

    PubMed

    Nogueira, L P; Braz, D; Barroso, R C; Oliveira, L F; Pinheiro, C J G; Dreossi, D; Tromba, G

    2010-12-01

    Conventional bone histomorphometry is an important method for quantitative evaluation of bone microstructure. X-ray computed microtomography is a non-invasive technique, which can be used to evaluate histomorphometric indices in trabecular bones (BV/TV, BS/BV, Tb.N, Tb.Th, Tb.Sp). In this technique, 3D images are used to quantify the whole sample, differently from the conventional one, in which the quantification is performed in 2D slices and extrapolated for 3D case. In this work, histomorphometric quantification using synchrotron 3D X-ray computed microtomography was performed to quantify the bone structure at different skeletal sites as well as to investigate the effects of bone diseases on quantitative understanding of bone architecture. The images were obtained at Synchrotron Radiation for MEdical Physics (SYRMEP) beamline, at ELETTRA synchrotron radiation facility, Italy. Concerning the obtained results for normal and pathological bones from same skeletal sites and individuals, from our results, a certain declining bone volume fraction was achieved. The results obtained could be used in forming the basis for comparison of the bone microarchitecture and can be a valuable tool for predicting bone fragility.

  11. Comparative study of INPIStron and spark gap

    NASA Technical Reports Server (NTRS)

    Han, Kwang S.; Lee, Ja H.

    1993-01-01

    An inverse pinch plasma switch, INPIStron, was studied in comparison to a conventional spark gap. The INPIStron is under development for high power switching applications. The INPIStron has an inverse pinch dynamics, opposed to Z-pinch dynamics in the spark gap. The electrical, plasma dynamics and radiative properties of the closing plasmas have been studied. Recently the high-voltage pulse transfer capabilities or both the INPIStron and the spark gap were also compared. The INPIStron with a low impedance Z = 9 ohms transfers 87 percent of an input pulse with a halfwidth of 2 mu s. For the same input pulse the spark gap of Z = 100 ohms transfers 68 percent. Fast framing and streak photography, taken with an TRW image converter camera, was used to observe the discharge uniformity and closing plasma speed in both switches. In order to assess the effects of closing plasmas on erosion of electrode material, emission spectra of two switches were studied with a spectrometer-optical multi channel analyzer (OMA) system. The typical emission spectra of the closing plasmas in the INPIStron and the spark gap showed that there were comparatively weak carbon line emission in 658.7 nm and copper (electrode material) line emissions in the INPIStron, indicating low erosion of materials in the INPIStron.

  12. Comparative study of hydrogenated and lithiated superhalogens

    NASA Astrophysics Data System (ADS)

    Xu, Li-Na; Li, Ying; Liu, Jia-Yuan; Wu, Di; Sun, Yan-Bo; Li, Zhi-Ru

    2016-09-01

    The structural features, properties and stability of two kinds of representative superhalogen compounds, namely hydrogenated superhalogens and lithiated superhalogens, are theoretically studied in detail, providing further insight into the behavior of superhalogens. According to topological analysis of the electron localization function, most of superhalogen clusters as a whole combine with Li atom through ionic bond(s). In contrast, the H atom tends to bind with superhalogen by covalent bond although a portion of superhalogens are broken upon hydrogenation. In addition, the electric properties of these superhalogen compounds are also obtained and compared with those of traditional acid and salt molecules.

  13. EFQPSK Versus CERN: A Comparative Study

    NASA Technical Reports Server (NTRS)

    Borah, Deva K.; Horan, Stephen

    2001-01-01

    This report presents a comparative study on Enhanced Feher's Quadrature Phase Shift Keying (EFQPSK) and Constrained Envelope Root Nyquist (CERN) techniques. These two techniques have been developed in recent times to provide high spectral and power efficiencies under nonlinear amplifier environment. The purpose of this study is to gain insights into these techniques and to help system planners and designers with an appropriate set of guidelines for using these techniques. The comparative study presented in this report relies on effective simulation models and procedures. Therefore, a significant part of this report is devoted to understanding the mathematical and simulation models of the techniques and their set-up procedures. In particular, mathematical models of EFQPSK and CERN, effects of the sampling rate in discrete time signal representation, and modeling of nonlinear amplifiers and predistorters have been considered in detail. The results of this study show that both EFQPSK and CERN signals provide spectrally efficient communications compared to filtered conventional linear modulation techniques when a nonlinear power amplifier is used. However, there are important differences. The spectral efficiency of CERN signals, with a small amount of input backoff, is significantly better than that of EFQPSK signals if the nonlinear amplifier is an ideal clipper. However, to achieve such spectral efficiencies with a practical nonlinear amplifier, CERN processing requires a predistorter which effectively translates the amplifier's characteristics close to those of an ideal clipper. Thus, the spectral performance of CERN signals strongly depends on the predistorter. EFQPSK signals, on the other hand, do not need such predistorters since their spectra are almost unaffected by the nonlinear amplifier, Ibis report discusses several receiver structures for EFQPSK signals. It is observed that optimal receiver structures can be realized for both coded and uncoded EFQPSK

  14. Comparative Study of Vented vs. Unvented Crawlspaces

    SciTech Connect

    Biswas, Kaushik; Christian, Jeffrey E; Gehl, Anthony C

    2011-10-01

    There has been a significant amount of research in the area of building energy efficiency and durability. However, well-documented quantitative information on the impact of crawlspaces on the performance of residential structures is lacking. The objective of this study was to evaluate and compare the effects of two crawlspace strategies on the whole-house performance of a pair of houses in a mixed humid climate. These houses were built with advanced envelope systems to provide energy savings of 50% or more compared to traditional 2010 new construction. One crawlspace contains insulated walls and is sealed and semi-conditioned. The other is a traditional vented crawlspace with insulation in the crawlspace ceiling. The vented (traditional) crawlspace contains fiberglass batts installed in the floor chase cavities above the crawl, while the sealed and insulated crawlspace contains foil-faced polyisocyanurate foam insulation on the interior side of the masonry walls. Various sensors to measure temperatures, heat flux through crawlspace walls and ceiling, and relative humidity were installed in the two crawlspaces. Data from these sensors have been analyzed to compare the performance of the two crawlspace designs. The analysis results indicated that the sealed and insulated crawlspace design is better than the traditional vented crawlspace in the mixed humid climate.

  15. Comparative study of methods for WHPA delineation.

    PubMed

    Paradis, Daniel; Martel, Richard; Karanta, Gilbert; Lefebvre, René; Michaud, Yves; Therrien, René; Nastev, Miroslav

    2007-01-01

    Human activities, whether agricultural, industrial, commercial, or domestic, can contribute to ground water quality deterioration. In order to protect the ground water exploited by a production well, it is essential to develop a good knowledge of the flow system and to adequately delineate the area surrounding the well within which potential contamination sources should be managed. Many methods have been developed to delineate such a wellhead protection area (WHPA). The integration of more information on the geologic and hydrogeologic characteristics of the study area increases the precision of any given WHPA delineation method. From a practical point of view, the WHPA delineation methods allowing the simplest and least expensive integration of the available information should be favored. This paper presents a comparative study in which nine different WHPA delineation methods were applied to a well and a spring in an unconfined granular aquifer and to a well in a confined highly fractured rock aquifer. These methods range from simple approaches to complex computer models. Hydrogeological mapping and numerical modeling with MODFLOW-MODPATH were used as reference methods to respectively compare the delineation of the zone of contribution and the zone of travel obtained from the various WHPA methods. Although applied to simple ground water flow systems, these methods provided a relatively wide range of results. To allow a realistic delineation of the WHPA in aquifers of variable geometry, a WHPA delineation method should ensure a water balance and include observed or calculated regional flow characteristics.

  16. A comparative study of teenage pregnancy.

    PubMed

    Mahavarkar, S H; Madhu, C K; Mule, V D

    2008-08-01

    Teenage pregnancy is a global problem and is considered a high-risk group, in spite of conflicting evidence. Our objective was to compare obstetric outcomes of pregnancy in teenagers and older women. This was a retrospective study of case records of pregnancies from August 2000 to July 2001. Girls aged < or =19 years were compared with pregnancy outcomes in older women (19-35 years) in the same hospital. The study took place in the Government General Hospital, Sangli, India, a teaching hospital in rural India, with an annual delivery rate of over 3,500. A total of 386 teenage pregnancies were compared with pregnancies in 3,326 older women. Socioeconomic data, age, number of pregnancies, antenatal care and complications, mode of delivery, and neonatal outcomes were considered. The incidence of teenage pregnancy in the study was 10%. A significant proportion of teenage pregnant mothers were in their first pregnancies. The teenage mothers were nearly three times more at risk of developing anaemia (OR = 2.83, 95% CI = 2.2-3.7, p < 0.0001) and delivering pre-term (OR = 2.97, 95% CI = 2.4-3.7, p < 0.0001). Teenage mothers were twice as likely to develop hypertensive problems in pregnancy (OR = 2.2, 95% CI = 1.5-3.2, p < 0.0001) and were more likely to deliver vaginally with no significant increase in the risk of assisted vaginal delivery or caesarean section. Young mothers were nearly twice at risk of delivering low birth weight babies (OR = 1.8, 95% CI = 1.5-2.2, p < 0.0001) and 50% less likely to have normal birth weight babies (OR = 0.5, 95% CI = 1.2-2.9, p < 0.0001). The outcome of this study showed that teenage pregnancies are still a common occurrence in rural India in spite of various legislations and government programmes and teenage pregnancy is a risk factor for poor obstetric outcome in rural India. Cultural practices, poor socioeconomic conditions, low literacy rate and lack of awareness of the risks are some of the main contributory factors. Early booking

  17. Scatterometry or imaging overlay: a comparative study

    NASA Astrophysics Data System (ADS)

    Hsu, Simon C. C.; Pai, Yuan Chi; Chen, Charlie; Yu, Chun Chi; Hsing, Henry; Wu, Hsing-Chien; Kuo, Kelly T. L.; Amir, Nuriel

    2015-03-01

    Most fabrication facilities today use imaging overlay measurement methods, as it has been the industry's reliable workhorse for decades. In the last few years, third-generation Scatterometry Overlay (SCOL™) or Diffraction Based Overlay (DBO-1) technology was developed, along another DBO technology (DBO-2). This development led to the question of where the DBO technology should be implemented for overlay measurements. Scatterometry has been adopted for high volume production in only few cases, always with imaging as a backup, but scatterometry overlay is considered by many as the technology of the future. In this paper we compare imaging overlay and DBO technologies by means of measurements and simulations. We outline issues and sensitivities for both technologies, providing guidelines for the best implementation of each. For several of the presented cases, data from two different DBO technologies are compared as well, the first with Pupil data access (DBO-1) and the other without pupil data access (DBO-2). Key indicators of overlay measurement quality include: layer coverage, accuracy, TMU, process robustness and robustness to process changes. Measurement data from real cases across the industry are compared and the conclusions are also backed by simulations. Accuracy is benchmarked with reference OVL, and self-consistency, showing good results for Imaging and DBO-1 technology. Process sensitivity and metrology robustness are mostly simulated with MTD (Metrology Target Designer) comparing the same process variations for both technologies. The experimental data presented in this study was done on ten advanced node layers and three production node layers, for all phases of the IC fabrication process (FEOL, MEOL and BEOL). The metrology tool used for most of the study is KLA-Tencor's Archer 500LCM system (scatterometry-based and imaging-based measurement technologies on the same tool) another type of tool is used for DBO-2 measurements. Finally, we conclude that

  18. Correlation between 3D microstructural and 2D histomorphometric properties of subchondral bone with healthy and degenerative cartilage of the knee joint.

    PubMed

    Lahm, Andreas; Kasch, Richard; Spank, Heiko; Erggelet, Christoph; Esser, Jan; Merk, Harry; Mrosek, Eike

    2014-11-01

    Cartilage degeneration of the knee joint is considered to be a largely mechanically driven process. We conducted a microstructural and histomorphometric analysis of subchondral bone samples of intact cartilage and in samples with early and higher- grade arthritic degeneration to compare the different states and correlate the findings with the condition of hyaline cartilage. These findings will enable us to evaluate changes in biomechanical properties of subchondral bone during the evolution of arthritic degeneration, for which bone density alone is an insufficient parameter. From a continuous series of 80 patients undergoing implantation of total knee endoprosthesis 30 osteochondral samples with lesions macroscopically classified as ICRS grade 1b (group A) and 30 samples with ICRS grade 3a or 3b lesions (group B) were taken. The bone samples were assessed by 2D histomorphometry (semiautomatic image analysis system) and 3D microstructural analysis (high-resolution micro-CT system). The cartilage was examined using the semiquantitative real-time PCR gene expression of collagen type I and II and aggrecan. Both histomorphometry and microstructural and biomechanical analysis of subchondral bone in groups A and B consistently revealed progressive changes of both bone and cartilage compared with healthy controls. The severity of cartilage degeneration as assessed by RT PCR was significantly correlated with BV/TV (Bone Volume Fraction), Tb.Th (Trabecular Thickness) showed a slight increase. Tb.N (Trabecular Number), Tb.Sp (Trabecular separation) SMI (Structure Model Index), Conn.D (Connectivity Density) and DA (Degree of Anisotropy) were inversely correlated. We saw sclerotic transformation and phagocytic reticulum cells. Bone volume fraction decreased with an increasing distance from the cartilage with the differences compared with healthy controls becoming greater in more advanced cartilage damage. The density of subchondral bone alone is considered an unreliable

  19. A comparative study of physiologic intracranial calcifications.

    PubMed

    Abbassioun, K; Aarabi, B; Zarabi, M

    1978-04-01

    It has been the impression of clinicians that pineal calcification is infrequent in Shiraz, Iran. In order to evaluate this clinical impression 2000 consecutive skul X-rays taken at Saadi Hospital, Shiraz, Iran, were reviewed for the presence of physiologic intracranial calcifications. The incidence of these clasifications in male and female in consecutive age groups of 10 years from 0 to over 70 years of age were assessed and compared with previous reports from other countries. The average incidence of pineal calcification for those over 20 years of age was 18.29% in this study compared with 55% in the U.S.A. The incidence of calcification in the choroid plexus and the falx cerebri was also considerably less than previously reported. The literature is reviewed and the possible causes for the geographical differences in the reported frequency of physiologic intracranial calcifications is discussed. It is possible that racial and dietary factors may be significant in the variation in the incidence of pineal and other cranial calcifications noted in different countries. Within a population group, age and sex are additional factors.

  20. Comparative study of boundary conditions with helix

    NASA Astrophysics Data System (ADS)

    Pillay, Shamini; Kumar, Deepak; Phua, Y. N.

    2016-11-01

    This paper presents a comparative study of dispersion characteristics of the circular waveguide with helical windings. Our waveguide is doubly unconventional in the choice of reverse boundary condition, in the choice of normal boundary condition and further with the presence of sheath helix between the core and cladding parameters. Two methods of winding the helix between the core and cladding are considered namely from right to left and left to right. Through mathematical analysis using field components and boundary conditions the modal characteristics are derived for both conditions. Normal boundary condition and reverse boundary conditions are used respectively to represent the helical windings. Here the characteristic equation is obtained in the form of Bessel and modified Bessel for both waveguides. Using the modal characteristic equation the dispersion curves are plotted for numerous angles and wavelengths. We find that the method of wrapping the helical material has significant effect on the dispersion properties with regards to the way the modes propagate.

  1. Comparative Study of Airfoil Flow Separation Criteria

    NASA Astrophysics Data System (ADS)

    Laws, Nick; Kahouli, Waad; Epps, Brenden

    2015-11-01

    Airfoil flow separation impacts a multitude of applications including turbomachinery, wind turbines, and bio-inspired micro-aerial vehicles. In order to achieve maximum performance, some devices operate near the edge of flow separation, and others use dynamic flow separation advantageously. Numerous criteria exist for predicting the onset of airfoil flow separation. This talk presents a comparative study of a number of such criteria, with emphasis paid to speed and accuracy of the calculations. We evaluate the criteria using a two-dimensional unsteady vortex lattice method, which allows for rapid analysis (on the order of seconds instead of days for a full Navier-Stokes solution) and design of optimal airfoil geometry and kinematics. Furthermore, dynamic analyses permit evaluation of dynamic stall conditions for enhanced lift via leading edge vortex shedding, commonly present in small flapping-wing flyers such as the bumblebee and hummingbird.

  2. Comparative studies on ecotoxicology of synthetic detergents.

    PubMed

    Lal, H; Misra, V; Viswanathan, P N; Krishna Murti, C R

    1983-12-01

    To predict the comparative toxicological response of synthetic detergents on aquatic ecosystems, the effects of various concentrations of neutralized alkyl benzene sulfonate were studied. The median tolerance limit at 48 hr, 95% confidence limit, slope function, presumable harmless concentration, and rate of survival of different species of aquatic fauna such as water fleas (Daphnia magna), mosquito larvae (Culex pipiens), slug worms (Tubifex rivulorum), snails (Lymnaea vulgaris), tadpoles (Rana cyanophlyctis), and fish fingerlings (Cirrhina mrigala) were followed at 0, 24, 48, 72, and 96 hr. Any effect on quality of the water was also tested after the addition of various concentrations of detergents. The results showed that water fleas are more susceptible to detergent toxicity than fish fingerlings, tadpoles, slug worms, snails, and mosquito larvae. Behavioral changes were also observed as an index for detergent toxicity. The relative toxicity of the detergents to various species is discussed in relation to selective ecotoxicological response.

  3. COSMOS - a study comparing peripheral intravenous systems.

    PubMed

    López, Juan Luis González; Del Palacio, Encarnación Ferenández; Marti, Carmen Benedicto; Corral, Javier Olivares; Portal, Pilar Herrera; Vilela, Ana Arribi

    In many areas of the world, safety peripheral intravenous systems have come into widespread use. The Madrid region was the first in Spain to adopt such an approach. These systems, though initially introduced to protect users from sharps injuries, have now evolved to include patient protection features as well. Patient protection, simply stated, means closing the system to pathogen entry. The authors' purpose was to investigate, in a prospective and randomized study, the clinical performance of a closed safe intravenous system versus an open system (COSMOS - Compact Closed System versus Mounted Open System). COSMOS is designed to provide definitive answers, from a nursing perspective, to many topics related to peripheral venous catheterization, which have important implications in intravenous therapy and which have not been validated scientifically. Furthermore, it forms pioneering research in that it is the first clinical trial on medical devices in a legislated environment carried out entirely by nurses and whose promoter and principal investigator is a nurse. The objectives of COSMOS are to compare the effectiveness (as defined by time of survival without complications) and rates of catheter-related complications, such as phlebitis, pain, extravasation, blockage and catheter-related infections. It also looks at rates of catheter colonization, the ease of handling of both systems and overall costs. This article outlines the authors' approach, both in preparing hospital units for such an evaluation as well as in the choice of parameters and their method of study. Further articles will detail the results and findings of the study.

  4. Protection against T1DM-Induced Bone Loss by Zinc Supplementation: Biomechanical, Histomorphometric, and Molecular Analyses in STZ-Induced Diabetic Rats.

    PubMed

    Bortolin, Raul Hernandes; da Graça Azevedo Abreu, Bento João; Abbott Galvão Ururahy, Marcela; Costa de Souza, Karla Simone; Bezerra, João Felipe; Loureiro, Melina Bezerra; da Silva, Flávio Santos; Marques, Dáfiny Emanuele da Silva; Batista, Angélica Amanda de Sousa; Oliveira, Gisele; Luchessi, André Ducati; Lima, Valéria Morgiana Gualberto Duarte Moreira; Miranda, Carlos Eduardo Saraiva; Lia Fook, Marcus Vinicius; Almeida, Maria das Graças; de Rezende, Luciana Augusto; de Rezende, Adriana Augusto

    2015-01-01

    Several studies have established an association between diabetes and alterations in bone metabolism; however, the underlying mechanism is not well established. Although zinc is recognized as a potential preventive agent against diabetes-induced bone loss, there is no evidence demonstrating its effect in chronic diabetic conditions. This study evaluated the effects of zinc supplementation in a chronic (90 days) type 1 diabetes-induced bone-loss model. Male Wistar rats were distributed in three groups: control, type 1 diabetes mellitus (T1DM), and T1DM plus zinc supplementation (T1DMS). Serum biochemical analysis; tibia histomorphometric, biomechanical, and collagen-content analyses; and femur mRNA expression were evaluated. Relative to T1DM, the zinc-supplemented group showed increased histomorphometric parameters such as TbWi and BAr and decreased TbSp, increased biomechanical parameters (maximum load, stiffness, ultimate strain, and Young's modulus), and increased type I collagen content. Interestingly, similar values for these parameters were observed between the T1DMS and control groups. These results demonstrate the protective effect of zinc on the maintenance of bone strength and flexibility. In addition, downregulation of OPG, COL1A, and MMP-9 genes was observed in T1DMS, and the anabolic effects of zinc were evidenced by increased OC expression and serum ALP activity, both related to osteoblastogenesis, demonstrating a positive effect on bone formation. In contrast, T1DM showed excessive bone loss, observed through reduced histomorphometric and biomechanical parameters, characterizing diabetes-associated bone loss. The bone loss was also observed through upregulation of OPG, COL1A, and MMP-9 genes. In conclusion, zinc showed a positive effect on the maintenance of bone architecture and biomechanical parameters. Indeed, OC upregulation and control of expression of OPG, COL1A, and MMP-9 mRNAs, even in chronic hyperglycemia, support an anabolic and protective

  5. Protection against T1DM-Induced Bone Loss by Zinc Supplementation: Biomechanical, Histomorphometric, and Molecular Analyses in STZ-Induced Diabetic Rats

    PubMed Central

    Bortolin, Raul Hernandes; da Graça Azevedo Abreu, Bento João; Abbott Galvão Ururahy, Marcela; Costa de Souza, Karla Simone; Bezerra, João Felipe; Bezerra Loureiro, Melina; da Silva, Flávio Santos; Marques, Dáfiny Emanuele da Silva; Batista, Angélica Amanda de Sousa; Oliveira, Gisele; Luchessi, André Ducati; Lima, Valéria Morgiana Gualberto Duarte Moreira; Miranda, Carlos Eduardo Saraiva; Lia Fook, Marcus Vinicius; Almeida, Maria das Graças; de Rezende, Luciana Augusto; de Rezende, Adriana Augusto

    2015-01-01

    Several studies have established an association between diabetes and alterations in bone metabolism; however, the underlying mechanism is not well established. Although zinc is recognized as a potential preventive agent against diabetes-induced bone loss, there is no evidence demonstrating its effect in chronic diabetic conditions. This study evaluated the effects of zinc supplementation in a chronic (90 days) type 1 diabetes-induced bone-loss model. Male Wistar rats were distributed in three groups: control, type 1 diabetes mellitus (T1DM), and T1DM plus zinc supplementation (T1DMS). Serum biochemical analysis; tibia histomorphometric, biomechanical, and collagen-content analyses; and femur mRNA expression were evaluated. Relative to T1DM, the zinc-supplemented group showed increased histomorphometric parameters such as TbWi and BAr and decreased TbSp, increased biomechanical parameters (maximum load, stiffness, ultimate strain, and Young’s modulus), and increased type I collagen content. Interestingly, similar values for these parameters were observed between the T1DMS and control groups. These results demonstrate the protective effect of zinc on the maintenance of bone strength and flexibility. In addition, downregulation of OPG, COL1A, and MMP-9 genes was observed in T1DMS, and the anabolic effects of zinc were evidenced by increased OC expression and serum ALP activity, both related to osteoblastogenesis, demonstrating a positive effect on bone formation. In contrast, T1DM showed excessive bone loss, observed through reduced histomorphometric and biomechanical parameters, characterizing diabetes-associated bone loss. The bone loss was also observed through upregulation of OPG, COL1A, and MMP-9 genes. In conclusion, zinc showed a positive effect on the maintenance of bone architecture and biomechanical parameters. Indeed, OC upregulation and control of expression of OPG, COL1A, and MMP-9 mRNAs, even in chronic hyperglycemia, support an anabolic and protective

  6. [Terconazol in vaginal candidiasis. Comparative study].

    PubMed

    Llaca Rodríguez, V; Carrión Tizcareño, H; Arguelles Domenzain, P

    1990-11-01

    The antimycotic action and tolerance to terconazole in patients with vaginal candidiasis, were evaluated in a blind study. The medication was given in vaginal ovules (VO) 240 mg, one dose per day, and 80 mg one daily dose for three days; as compared to chlotrimazole, VO 200 mg, daily dose for three days. The patients presented with vaginal candidiasis demonstrated by Nickerson culture medium. Sixty patients were studied in three equivalent groups. The mates of patients treated with terconazole had no treatment; and the mates of patients treated with chlotrimazole received urinary acidifying medication. Symptomatology and mycologic findings were evaluated at 10 and 28 days post treatment. Mycological cure rates at 10 days were: 90 per cent for the terconazole group, 240 mg, one dose; and 95 per cent for patients with terconazole, 80 mg, daily dose for three days; or chlotrimazole, 200 mg, daily dose for three days. Twenty eight days post-treatment, laboratory tests were positive again: 50%, 40% and 15%, respectively. Recidive in patients treated with terconazole, is explained by lack of treatment in mates. In conclusion, terconazole offers a high percentage of clinical and mycological cure in vaginal candidiasis, and it is indispensable treatment for the mate, in order to avoid recidives.

  7. [Terconazole in vaginal candidiasis. A comparative study].

    PubMed

    Llaca Rodríguez, V; Carrión Tizcareño, H; Arguelles Domenzain, P

    1990-11-01

    The antimycotic action and tolerance to terconazole in patients with vaginal candidiasis, were evaluated in a blind study. The medication was given in vaginal ovules (VO)240 mg, one dose per day, and 80 mg one daily dose for three days; as compared to chlotrimazole, VO 200 mg, daily dose for three days. The patients presented with vaginal candidiasis demonstrated by Nickerson culture medium. Sixty patients were studied in three equivalent groups. The mates of patients treated with terconazole had no treatment; and the mates of patients treated with chlotrimazole received urinary acidifying medication. Symptomatology and mycologic findings were evaluated at 10 and 28 days post treatment. Mycological cure rates at 10 days were: 90 per cent for the terconazole group, 240 mg, one dose; and 95 per cent for patients with terconazole, 80 mg, daily dose for three days; or chlotrimazole, 200 mg, daily dose for three days. Twenty eight days post-treatment, laboratory tests were positive again: 50%, 40% and 15%, respectively. Recidive in patients treated with terconazole, is explained by lack of treatment in mates. In conclusion, terconazole offers a high percentage of clinical and mycological cure in vaginal candidiasis, and it is indispensable treatment for the mate, in order to avoid recidives.

  8. A comparative study of barrier membranes as graft protectors in the treatment of localized bone defects. An experimental study in a canine model.

    PubMed

    Stavropoulos, Franci; Dahlin, Christer; Ruskin, James D; Johansson, Carina

    2004-08-01

    Guided bone regeneration is a predictable and well-documented surgical approach for the treatment of deficient alveolar ridges prior to endosseous implant placement. The purpose of this study was to compare a new resorbable membrane (GORE RESOLUT ADAPT Regenerative Membrane, i.e. 67% glycolide (PGA) : 33% trimethyline carbonate (TMC)) with Bio-Gide, a resorbable collagen membrane. Five canines were used in the study. Three saddle-type osseous defects were created bilaterally in edentulous areas of the mandible. The defects were filled with assayed, canine demineralized freeze-dried bone (DFDB) in a thermoplastic gelatin matrix. Using a randomized block design, four sites were covered with PGA : TMC membranes of four different porosities, one site was covered with a collagen membrane and one site consisted of DFDB alone (control). At 3 months, the animals were euthanized and the mandibles were removed en bloc for laboratory processing. A total of 30 sites were reviewed microradiographically and underwent histomorphometric analysis for bone regeneration, soft tissue presence and remaining graft material. All sites exhibited uneventful healing. A significantly higher percentage of bone regeneration was seen in the sites protected by the PGA : TMC membrane. A higher component of soft tissue was visible beneath the collagen membrane as compared with the PGA : TMC membrane. The control sites exhibited noticeable deformation of the regenerated bone secondary to collapse of the overlying periosteum. The authors conclude that the PGA : TMC membrane protected the DFDB-filled defect and allowed a greater amount of bone regeneration than the defect protected by the collagen membrane or the control.

  9. Comparative study of selected parallel tempering methods

    NASA Astrophysics Data System (ADS)

    Malakis, A.; Papakonstantinou, T.

    2013-07-01

    We review several parallel tempering schemes and examine their main ingredients for accuracy and efficiency. The present study covers two selection methods of temperatures and several choices for the exchange of replicas, including a recent novel all-pair exchange method. We compare the resulting schemes and measure specific heat errors and efficiency using the two-dimensional (2D) Ising model. Our tests suggest that an earlier proposal for using numbers of local moves related to the canonical correlation times is one of the key ingredients for increasing efficiency, and protocols using cluster algorithms are found to be very effective. Some of the protocols are also tested for efficiency and ground state production in 3D spin-glass models where we find that a simple nearest-neighbor approach using a local n-fold-way algorithm is the most effective. Finally, we present evidence that the asymptotic limits of the ground state energy for the isotropic case and for an anisotropic case of the 3D spin-glass model are very close and may even coincide.

  10. Biosafe alternative to xylene: A comparative study

    PubMed Central

    Negi, Amita; Puri, Abhiney; Gupta, Rakhi; Chauhan, Isha; Nangia, Rajat; Sachdeva, Alisha

    2013-01-01

    Background: Xylene in one of the non-substitutable chemical used in histology laboratories. However, it is known to have many toxic effects. The toxic effects of xylene include heart and kidney injuries, some fatal blood dyscrasia and other less dangerous problems, such as skin erythema, drying, scaling and secondary infections. The exposure and handling of xylene is maximum during deparaffinizing tissue sections. Aims: The aim of this study was to evaluate the efficacy of 1.7% dishwashing soap (DWS) solution as a deparaffinizing agent for hematoxylin and eosin (H and E) staining and compare it with xylene. Materials and Methods: Sixty sections of 4 μm were obtained from 30 formalin-fixed paraffin-embedded (FFPE) tissues and were considered in two different groups, groups A and B. Slides in group A were stained with routine H and E staining procedure; whereas, slides in group B were stained using 1.7% DWS as a deparaffinizing agent. Statistical Analysis Used: Wilcoxon matched-pairs signed rank test was used to calculate the test of significance (P-value significant at ≤0.05). Results and Conclusion: 1.7% DWS was found to be an effective alternative deparaffinizing agent to xylene and meanwhile facilitating as less biohazardous, economical and a faster deparaffinizing agent. PMID:24574653

  11. Assays for mammalian tyrosinase: a comparative study

    SciTech Connect

    Jara, J.R.; Solano, F.; Lozano, J.A.

    1988-01-01

    This work describes a comparative study of the tyrosinase activity determined using three methods which are the most extensively employed; two radiometric assays using L-tyrosine as substrate (tyrosine hydroxylase and melanin formation activities) and one spectrophotometric assay using L-dopa (dopa oxidase activity). The three methods were simultaneously employed to measure the activities of the soluble, melanosomal, and microsomal tyrosinase isozymes from Harding-Passey mouse melanoma through their purification processes. The aim of this study was to find any correlation among the tyrosinase activities measured by the three different assays and to determine whether that correlation varied with the isozyme and its degree of purification. The results show that mammalian tyrosinase has a greater turnover number for L-dopa than for L-tyrosine. Thus, enzyme activity, expressed as mumol of substrate transformed per min, is higher in assays using L-dopa as substrate than those using L-tyrosine. Moreover, the percentage of hydroxylated L-tyrosine that is converted into melanin is low and is affected by several factors, apparently decreasing the tyrosinase activity measured by the melanin formation assay. Bearing these considerations in mind, average interassay factors are proposed. Their values are 10 to transform melanin formation into tyrosine hydroxylase activity, 100 to transform tyrosine hydroxylase into dopa oxidase activity, and 1,000 to transform melanin formation into dopa oxidase activity. Variations in these values due to the presence in the tyrosinase preparations of either inhibitors or regulatory factors in melanogenesis independent of tyrosinase are also discussed.

  12. [Investigation of tibial bones of the rats exposed on board "Spacelab-2":histomorphometric analysis

    NASA Technical Reports Server (NTRS)

    Durnova, G. N.; Kaplanskii, A. S.; Morey-Holton, E. R.; Vorobeva, V. N.

    1996-01-01

    Proximal metaphyses of tibial bones from the Sprague-Dowly rats exposed in US dedicated space life sciences laboratory SLS-2 for 13-14 days and sacrificed on day 13 in microgravity and within 5 hours and 14 days following recovery were the subject of histological, histochemical, and histomorphometric analyses. After the 13-day flight of SLS-2 the rats showed initial signs of osteopenia in the spongy tissue of tibial bones, secondary spongiosis affected first. Resorption of the secondary spongiosis was consequent to enhanced resorption and inhibition of osteogenesis. In rats sacrificed within 5 hours of recovery manifestations of tibial osteopenia were more evident than in rats sacrificed during the flight. Spaceflight-induced changes in tibial spongiosis were reverse by character the amount of spongy bone was fully compensated and following 14 days of readaptation to the terrestrial gravity.

  13. [Investigation of tibial bones of the rats exposed on board "Spacelab-2":histomorphometric analysis].

    PubMed

    Durnova, G N; Kaplanskii, A S; Morey-Holton, E R; Vorobéva, V N

    1996-01-01

    Proximal metaphyses of tibial bones from the Sprague-Dowly rats exposed in US dedicated space life sciences laboratory SLS-2 for 13-14 days and sacrificed on day 13 in microgravity and within 5 hours and 14 days following recovery were the subject of histological, histochemical, and histomorphometric analyses. After the 13-day flight of SLS-2 the rats showed initial signs of osteopenia in the spongy tissue of tibial bones, secondary spongiosis affected first. Resorption of the secondary spongiosis was consequent to enhanced resorption and inhibition of osteogenesis. In rats sacrificed within 5 hours of recovery manifestations of tibial osteopenia were more evident than in rats sacrificed during the flight. Spaceflight-induced changes in tibial spongiosis were reverse by character the amount of spongy bone was fully compensated and following 14 days of readaptation to the terrestrial gravity.

  14. [Histomorphometric analysis of the bones of rats on board the Kosmos 1667 biosatellite].

    PubMed

    Kaplanskiĭ, A S; Durnova, G N; Sakharova, Z F; Il'ina-Kakueva, E I

    1987-01-01

    Bones of the rats flown on Cosmos-1667 were examined histologically and histomorphometrically. It was found that 7-day exposure to weightlessness led to osteoporosis in the spongy matter of proximal metaphyses of tibia and, although to a lesser extent, in the spongiosa of lumbar vertebrae whereas no signs of osteoporosis were seen in the spongy matter of iliac bones. Osteoporosis in the spongy matter of the above bones developed largely due to the inhibition of bone neoformation, which was indicated by a decrease in the number and activity of osteoblasts. Increased bone resorption (as shown by a greater number and activity of osteoclasts) was observed only in the spongy matter of tibial metaphyses. It is emphasized that a reduction of the number of highly active osteoblasts in spongy bones is one of the early signs of inhibition of bone neoformation and development of osteoporosis.

  15. Morphological and histomorphometric evaluation of the ventral rectus sheath of the rectus abdominis muscle, fascia lata and pectoral fascia. The beginning of a morphological information bank of human fascias.

    PubMed

    Morales-Avalos, Rodolfo; Soto-Domínguez, Adolfo; García-Juárez, Jaime; Cardenas-Serna, Marcela; Esparza-Hernández, Claudia N; Carreño-Salcedo, Sofía Alejandra; Montes-de-Oca-Luna, Roberto; Loera-Arias, María de Jesús; Saucedo-Cárdenas, Odila; Elizondo-Omaña, Rodrigo E; Guzmán-López, Santos

    2017-03-01

    The aim of this study was to characterize and compare the morphological and histomorphometric characteristics of the pectoral fascia, fascia lata and ventral rectus sheath. Twenty cadaveric samples of these fascias were analyzed and stained with hematoxylin and eosin, orcein, Van Gieson, Masson's trichrome and Verhoeff¨s stain (1200 slides in total). Morphological evaluation, semiquantitative, morphometric and microdensitometric analysis of elastic fibers present in each of the tissues and a morphometrical analysis of tissue thickness were performed. The mean value of the pectoral fascia thickness was 612±68.13 μm; 84±246 μm for the fascia lata and 584±92 μm for the ventral rectus sheath. The area occupied by the elastic fibers in the pectoral fascia was 12.24±5.84%; 6,54±3.85% for the fascia lata and 11.11±5.26% for the ventral rectus sheath. There were no statistically significant differences when comparing the mean values between the pectoral fascia and the ventral rectus sheath (p=0.07). There were statistically significant differences when comparing the fascia lata to the pectoral fascia and the ventral rectus sheath (p≤0.001). This study reports other morphological characteristics not described in previous histological studies of the analyzed tissues. The results of the morphometric and densitometric analysis in this study reveal that the fascia lata has the fewest elastic fibers of all the tissues analyzed, and the pectoral fascia has the most. These results will be useful for the beginning of a morphological information bank of human fascias.

  16. Histomorphometric evaluation of intestinal cellular immune responses in pigs immunized with live oral F4ac+ non-enterotoxigenic E. coli vaccine against postweaning colibacillosis

    PubMed Central

    Kovšca Janjatović, A.; Lacković, G.; Božić, F.; Kezić, D.; Popović, M.; Valpotić, H.; Harapin, I.; Pavižić, Ž.; Njari, B.; Valpotić, I.

    2010-01-01

    ileal cell subsets tested were significantly increased (at P<0.5 or lower) in both principal groups (vaccinated or levamisole primed-vaccinated) of pigs, compared to those recorded in the control non-vaccinated pigs. Based on the histomorphometric quantification of porcine intestinal immune cells from the GALT compartments tested, it is possible to differentiate the responses of pigs immunized by an experimental mucosal vaccine from those of non-immunized pigs. PMID:20353911

  17. A Comparative Study Of Dust Devils

    NASA Astrophysics Data System (ADS)

    Lange, C. F.; Prieto, L. E.

    2005-12-01

    computational models. This was accomplished by examining features of the dust devils in the form of three main flow parameters: the ratio of the inflow layer height h to the updraft radius r_0 (aspect ratio), the radial Reynolds number characterizing the updraft zone, and the ratio of the tangential velocity to the mean radial velocity (swirl ratio) at the radius of the updraft zone, r_0. The detailed analysis of the numerical flow solutions led to a simple definition of h and r_0, valid for the types of model flows analyzed. This study is a necessary part of a larger effort to examine and compare both numerical and laboratory simulations of atmospheric vortices in terrestrial and Martian conditions. References [1] R. Greeley et al., XXXII Lunar and Planetary Science, 2001. [2] D. E. Lund and J. T. Snow, The Tornado: Its Structure, Dynamics, Prediction, and Hazards, 1993, p. 297--306. [3] N. B. Ward, J. Atmos. Sci., 1972, 1194--1204.

  18. Comparative Study of Two Automatic Registration Algorithms

    NASA Astrophysics Data System (ADS)

    Grant, D.; Bethel, J.; Crawford, M.

    2013-10-01

    The Iterative Closest Point (ICP) algorithm is prevalent for the automatic fine registration of overlapping pairs of terrestrial laser scanning (TLS) data. This method along with its vast number of variants, obtains the least squares parameters that are necessary to align the TLS data by minimizing some distance metric between the scans. The ICP algorithm uses a "model-data" concept in which the scans obtain differential treatment in the registration process depending on whether they were assigned to be the "model" or "data". For each of the "data" points, corresponding points from the "model" are sought. Another concept of "symmetric correspondence" was proposed in the Point-to-Plane (P2P) algorithm, where both scans are treated equally in the registration process. The P2P method establishes correspondences on both scans and minimizes the point-to-plane distances between the scans by simultaneously considering the stochastic properties of both scans. This paper studies both the ICP and P2P algorithms in terms of their consistency in registration parameters for pairs of TLS data. The question being investigated in this paper is, should scan A be registered to scan B, will the parameters be the same if scan B were registered to scan A? Experiments were conducted with eight pairs of real TLS data which were registered by the two algorithms in the forward (scan A to scan B) and backward (scan B to scan A) modes and the results were compared. The P2P algorithm was found to be more consistent than the ICP algorithm. The differences in registration accuracy between the forward and backward modes were negligible when using the P2P algorithm (mean difference of 0.03 mm). However, the ICP had a mean difference of 4.26 mm. Each scan was also transformed by the forward and backward parameters of the two algorithms and the misclosure computed. The mean misclosure for the P2P algorithm was 0.80 mm while that for the ICP algorithm was 5.39 mm. The conclusion from this study is

  19. Histomorphometric Assessment of the Influence of Low-Level Laser Therapy on Peri-Implant Tissue Healing in the Rabbit Mandible

    PubMed Central

    Gomes, Fernando Vacilotto; Mayer, Luciano; de Oliveira, Marília Gerhardt; Baraldi, Carlos Eduardo; Ponzoni, Deise; Puricelli, Edela

    2015-01-01

    Abstract Objective: The purpose of this study was to demonstrate the effect of low-level laser therapy (LLLT) on the peri-implant bone healing process in the rabbit mandible. Background data: LLLT has been shown to accelerate tissue repair and osseointegration of implants placed into the rabbit tibia. However, the beneficial effects of LLLT have never been tested in the rabbit mandible, which would more closely mimic the human situation. Materials and methods: Twenty-four male New Zealand rabbits were randomly divided into four groups of six animals each. All animals had their left mandibular incisors extracted, followed by immediate insertion of a titanium dental implant in the fresh socket. Three groups received LLLT [aluminum-gallium-arsenide (AlGaAs), λ=830nm, 50 mW, continuous wave (CW)] at three different energy densities per treatment session (E-5, 5 J/cm2; E-10, 10 J/cm2; and E-20, 20 J/cm2). Irradiation was performed every 48 h for 13 days, totaling seven sessions. One group received sham treatment (controls). Histological sections were obtained from each of the 24 mandibles dissected, without first decalcifying the specimens, and were stained with hematoxylin and eosin and Picrosirius red for histomorphometric evaluation. Bone-to-implant contact (BIC), bone formation area, and collagen fiber area were assessed by light microscopy. Results: Significant differences were found between group E-20 and all other groups (p<0.05). Histomorphometric evaluation showed significantly higher BIC and significantly more collagen fibers in group E-20. Conclusions: Photobiostimulation with LLLT at an energy density of 20 J/cm2 per session had a significant positive effect on new bone formation around dental implants inserted in the rabbit mandible. PMID:25751666

  20. Flip This Classroom: A Comparative Study

    ERIC Educational Resources Information Center

    Unruh, Tiffany; Peters, Michelle L.; Willis, Jana

    2016-01-01

    The purpose of this research was to compare the beliefs and attitudes of teachers using the flipped versus the traditional class model. Survey and interview data were collected from a matched sample of in-service teachers representing both models from a large suburban southeastern Texas school district. The Attitude Towards Technology Scale, the…

  1. Counseling in Costa Rica: A Comparative Study

    ERIC Educational Resources Information Center

    Collier, Crystal

    2013-01-01

    With one of the world's most comprehensive universal healthcare systems, medical tourism in Costa Rica has increased significantly over the past few decades. American tourists save up to 80% of comparative costs for procedures, from heart surgery to root canal treatment. Although many Costa Rican healthcare professionals receive training in North…

  2. Histomorphometric, physical, and mechanical effects of spaceflight and insulin-like growth factor-I on rat long bones.

    PubMed

    Bateman, T A; Zimmerman, R J; Ayers, R A; Ferguson, V L; Chapes, S K; Simske, S J

    1998-12-01

    Previous experiments have shown that skeletal unloading resulting from exposure to microgravity induces osteopenia in rats. In maturing rats, this is primarily a function of reduced formation, rather than increased resorption. Insulin-like growth factor-I (IGF-I) stimulates bone formation by increasing collagen synthesis by osteoblasts. The ability of IGF-I to prevent osteopenia otherwise caused by spaceflight was investigated in 12 rats flown for 10 days aboard the Space Shuttle, STS-77. The effect IGF-I had on cortical bone metabolism was generally anabolic. For example, humerus periosteal bone formation increased a significant 37.6% for the spaceflight animals treated with IGF-I, whereas the ground controls increased 24.7%. This increase in humeral bone formation at the periosteum is a result of an increased percent mineralizing perimeter (%Min.Pm), rather than mineral apposition rate (MAR), for both spaceflight and ground control rats. However, IGF-I did inhibit humerus endocortical bone formation in both the spaceflight and ground control rats (38.1% and 39.2%, respectively) by limiting MAR. This effect was verified in a separate ground-based study. Similar histomorphometric results for spaceflight and ground control rats suggest that IGF-I effects occur during normal weight bearing and during spaceflight. Microhardness measurements of the newly formed bone indicate that the quality of the bone formed during IGF-I treatment or spaceflight was not adversely altered. Spaceflight did not consistently change the structural (force-deflection) properties of the femur or humerus when tested in three-point bending. IGF-I significantly increased femoral maximum and fracture strength.

  3. Advertisement Analysis: A Comparative Critical Study

    ERIC Educational Resources Information Center

    Abdelaal, Noureldin Mohamed; Sase, Amal Saleh

    2014-01-01

    This study aimed at analyzing two advertisements, and investigating how advertisers use discourse and semiotics to make people and customers buy into their ideas, beliefs, or simply their products. The two advertisements analyzed are beauty products which have been selected from internet magazines. The methodology adopted in this study is…

  4. A Comparative Study of Landmine Detection Techniques

    NASA Astrophysics Data System (ADS)

    Kasban, H.; Zahran, O.; Elaraby, Sayed M.; El-Kordy, M.; Abd El-Samie, F. E.

    2010-09-01

    Several countries suffer from the existence of millions of buried landmines in their territories. These landmines have indefinite life, and may still cause horrific personal injuries and economic dislocation for decades after a war has finished. Therefore, there is a growing demand by these countries for reliable landmine inspection systems. There are several landmine detection techniques that can be used for this purpose. Each technique is suitable for detection under some conditions depending on the type of the landmine case, the explosive material, and the soil. This paper presents an overview of some of the existing landmine detection techniques. These techniques are briefly described and their merits and drawbacks are highlighted and compared. The purpose of this comparison is to shows the ideal conditions and the challenges for each technique. Furthermore, a comparison between landmine detection techniques from the points of view of cost, complexity, speed, safety, false alarm rate and effect of environmental conditions is presented.

  5. A comparative study of staff removal algorithms.

    PubMed

    Dalitz, Christoph; Droettboom, Michael; Pranzas, Bastian; Fujinaga, Ichiro

    2008-05-01

    This paper presents a quantitative comparison of different algorithms for the removal of stafflines from music images. It contains a survey of previously proposed algorithms and suggests a new skeletonization based approach. We define three different error metrics, compare the algorithms with respect to these metrics and measure their robustness with respect to certain image defects. Our test images are computer-generated scores on which we apply various image deformations typically found in real-world data. In addition to modern western music notation our test set also includes historic music notation such as mensural notation and lute tablature. Our general approach and evaluation methodology is not specific to staff removal, but applicable to other segmentation problems as well.

  6. Comparative Study of Light Sources for Household

    NASA Astrophysics Data System (ADS)

    Pawlak, Andrzej; Zalesińska, Małgorzata

    2017-03-01

    The article describes test results that provided the ground to define and evaluate basic photometric, colorimetric and electric parameters of selected, widely available light sources, which are equivalent to a traditional incandescent 60-Watt light bulb. Overall, one halogen light bulb, three compact fluorescent lamps and eleven LED light sources were tested. In general, it was concluded that in most cases (branded products, in particular) the measured and calculated parameters differ from the values declared by manufacturers only to a small degree. LED sources prove to be the most beneficial substitute for traditional light bulbs, considering both their operational parameters and their price, which is comparable with the price of compact fluorescent lamps or, in some instances, even lower.

  7. Metacognition and Group Differences: A Comparative Study

    ERIC Educational Resources Information Center

    Al-Hilawani, Yasser A.

    2014-01-01

    In this study, metacognition refers to performing visual analysis and discrimination of real life events and situations in naïve psychology, naïve physics, and naïve biology domains. It is used, along with measuring reaction time, to examine differences in the ability of four groups of students to select appropriate pictures that correspond with…

  8. Children's Friendship Development: A Comparative Study

    ERIC Educational Resources Information Center

    Yu, SeonYeong; Ostrosky, Michaelene M.; Fowler, Susan A.

    2011-01-01

    Establishing friendships is an important developmental goal of early childhood, but little research has addressed ways in which parents support the friendship development of their young children with disabilities. The purpose of this survey study was to explore the support strategies that parents use to facilitate their children's friendships.…

  9. Comparative U.S.-Mexico Border Studies.

    ERIC Educational Resources Information Center

    Stoddard, Ellwyn R., Ed.

    Four United States universities, one from each American state having a common boundary with Mexico, organized the Border-State University Consortium for Latin America. The organization emerged as an attempt to focus collectively on problems and situations immediately accessible for study in a series of publications entitled "Occasional…

  10. Implicature, Pragmatics, and Documentation: A Comparative Study

    ERIC Educational Resources Information Center

    Wright, David

    2008-01-01

    This study investigates the link between the linguistic principles of implicature and pragmatics and software documentation. When implicatures are created in conversation or text, the listener or reader is required to fill in missing information not overtly stated. This information is usually filled in on the basis of previous knowledge or…

  11. Articulation of Quality Teaching: A Comparative Study

    ERIC Educational Resources Information Center

    Sakarneh, Mohammad

    2015-01-01

    The aim of this study is to describe and then contrast the New South Wales Department of Education and Training's model of quality teaching with the Jordanian Ministry of Education's conception of quality teaching, looking particularly at potential differences in interpretation. A content analysis methodology was used. Each perspective has been…

  12. LES versus DNS: A comparative study

    NASA Technical Reports Server (NTRS)

    Shtilman, L.; Chasnov, J. R.

    1992-01-01

    We have performed Direct Numerical Simulations (DNS) and Large Eddy Simulations (LES) of forced isotropic turbulence at moderate Reynolds numbers. The subgrid scale model used in the LES is based on an eddy viscosity which adjusts instantaneously the energy spectrum of the LES to that of the DNS. The statistics of the large scales of the DNS (filtered DNS field or fDNS) are compared to that of the LES. We present results for the transfer spectra, the skewness and flatness factors of the velocity components, the PDF's of the angle between the vorticity and the eigenvectors of the rate of strain, and that between the vorticity and the vorticity stretching tensor. The above LES statistics are found to be in good agreement with those measured in the fDNS field. We further observe that in all the numerical measurements, the trend was for the LES field to be more gaussian than the fDNS field. Future research on this point is planned.

  13. Earthquake correlations and networks: A comparative study

    SciTech Connect

    Krishna Mohan, T. R.; Revathi, P. G.

    2011-04-15

    We quantify the correlation between earthquakes and use the same to extract causally connected earthquake pairs. Our correlation metric is a variation on the one introduced by Baiesi and Paczuski [M. Baiesi and M. Paczuski, Phys. Rev. E 69, 066106 (2004)]. A network of earthquakes is then constructed from the time-ordered catalog and with links between the more correlated ones. A list of recurrences to each of the earthquakes is identified employing correlation thresholds to demarcate the most meaningful ones in each cluster. Data pertaining to three different seismic regions (viz., California, Japan, and the Himalayas) are comparatively analyzed using such a network model. The distribution of recurrence lengths and recurrence times are two of the key features analyzed to draw conclusions about the universal aspects of such a network model. We find that the unimodal feature of recurrence length distribution, which helps to associate typical rupture lengths with different magnitude earthquakes, is robust across the different seismic regions. The out-degree of the networks shows a hub structure rooted on the large magnitude earthquakes. In-degree distribution is seen to be dependent on the density of events in the neighborhood. Power laws, with two regimes having different exponents, are obtained with recurrence time distribution. The first regime confirms the Omori law for aftershocks while the second regime, with a faster falloff for the larger recurrence times, establishes that pure spatial recurrences also follow a power-law distribution. The crossover to the second power-law regime can be taken to be signaling the end of the aftershock regime in an objective fashion.

  14. A comparative study of crested gibbons (Nomascus).

    PubMed

    Mootnick, Alan R; Fan, Peng-Fei

    2011-02-01

    Crested gibbons (Nomascus) are in the rarest genus of the family Hylobatidae, with the Hainan gibbon (Nomascus hainanus) being the rarest primate in the world. In the past, the number of species in this genus has been at the center of much controversy, in part, because their color changes during immaturity as well as other factors, such as physical similarities in genitalia, creating difficulties in accurately determining the sex of individuals. Furthermore, owing to their rarity, illusiveness, and the rough terrain that comprises their native habitat, Nomascus is one of the least studied Hylobatidae. This article represents the most comprehensive dissemination of visual characteristics of the genus Nomascus to assist in the accurate identification of captive and wild crested gibbons. Through differences in pelage color, skeletal anatomy, dentition, vocalizations, behavior, distribution, and genetic studies, we are able to determine more accurately whether or not a subspecies should be elevated to species level. From the current data, there are six species and one subspecies in the genus Nomascus. However, reports of a recently identified light-cheeked gibbon (Nomascus sp.) in northeast Cambodia, Central Vietnam, and South Lao PDR, will add additional taxa to this genus.

  15. A comparative study of blood warmer performance.

    PubMed

    Uhl, L; Pacini, D; Kruskall, M S

    1992-11-01

    Massive transfusions of refrigerator-temperature blood may induce hypothermia and life-threatening arrhythmias; for this reason a variety of devices have been developed for rapid blood warming. Blood warmers available in the United States use one of three warming technologies: dry heat, water bath, or countercurrent heat exchange. In the current study we evaluated blood warmers representative of each technology for speed and extent of heat transfer: the Fenwal blood warmer (Fenwal Laboratories; dry heat), the DW-1000 (American Pharmaseal Co.; dry heat), the FloTem IIe (DataChem Inc.; dry heat), the Hemokinetitherm (Dupaco Inc.; water bath), and the H250 and H500 (Level 1 Technologies; countercurrent heat exchange). Only one countercurrent heat instrument (the H500) was able to heat blood > or = 33 degrees C at target flow rates > or = 250 ml/min. Dry heat and water bath blood warmers were unable to warm blood > or = 33 degrees C at target flow rates > or = 100 ml/min. High resistance to flow with the proprietary tubing required for one instrument (the Hemokinetitherm) prevented tests of blood warming at rates > 150 ml/min. We found that instruments that used countercurrent technology warmed blood and saline more effectively than did blood warmers that used either dry heat or water bath technology. Our study also demonstrated the need for close control and standardization of experimental conditions in the evaluation of blood warming devices.

  16. Comparative study on dermatoglyphics in alcoholic patients.

    PubMed

    Devcić, Sanja; Mihanović, Mate; Milicić, Jasna; Glamuzina, Ljubomir; Silić, Ante

    2009-12-01

    According to the world's prevalence rate, alcoholism is in the third place after heart and blood vessel diseases and malignant tumors. With the development of neuroscience, the causes of alcoholism's biological etiologic sources are still being studied. Considering that dermatoglyphics are highly determined by heritage, we contemplated the possibilities of their discrimination in alcoholic patients in relation to phenotypically healthy subjects. We analyzed the quantitative and qualitative dermatoglyphics properties of 100 alcoholic patients without psychiatric comorbidity, who have been cured in the Psychiatric Hospital Sveti Ivan two or more times, and those of 100 phenotypically healthy men. Through the t-test we evaluated the heterogeneity of the examined groups. Results showed a statistically significant difference on five examined variables. In the calculation of fluctuating asymmetry measure, we found no statistically significant differences in the correlation of values of the right and the left hand on the tested variables, beside one. Chi-square tests showed that there is no relation between the dermatoglyphic qualitative properties of alcoholic patients and those of the examinees from the comparison group. Despite the indisputable genetic role in the genesis of alcoholism, the analysis of the dermatoglyphics carried out in our study did not show any etiological connection between the results of the test on dermatoglyphics and the appearance of alcoholism.

  17. Neurodevelopmental treatment after stroke: a comparative study

    PubMed Central

    Hafsteinsdottir, T; Algra, A; Kappelle, L; Grypdonck, M; on, b

    2005-01-01

    Background: Neurodevelopmental treatment (NDT) is a rehabilitation approach increasingly used in the care of stroke patients, although no evidence has been provided for its efficacy. Objective: To investigate the effects of NDT on the functional status and quality of life (QoL) of patients with stroke during one year after stroke onset. Methods: 324 consecutive patients with stroke from 12 Dutch hospitals were included in a prospective, non-randomised, parallel group study. In the experimental group (n = 223), nurses and physiotherapists from six neurological wards used the NDT approach, while conventional treatment was used in six control wards (n = 101). Functional status was assessed by the Barthel index. Primary outcome was "poor outcome", defined as Barthel index <12 or death after one year. QoL was assessed with the 30 item version of the sickness impact profile (SA-SIP30) and the visual analogue scale. Results: At 12 months, 59 patients (27%) in the NDT group and 24 (24%) in the non-NDT group had poor outcome (corresponding adjusted odds ratio = 1.7 (95% confidence interval, 0.8 to 3.5)). At discharge the adjusted odds ratio was 0.8 (0.4 to 1.5) and after six months it was 1.6 (0.8 to 3.2). Adjusted mean differences in the two QoL measures showed no significant differences between the study groups at six or 12 months after stroke onset. Conclusions: The NDT approach was not found effective in the care of stroke patients in the hospital setting. Health care professionals need to reconsider the use of this approach. PMID:15897499

  18. [The effect of alpha-liponic acid, vitamin B or gangliosides on the regeneration of traumatically damaged peripheral nerves in the rat. A comparative, morphometric study].

    PubMed

    Stotzem, C D; Mengs, U

    1988-05-01

    The sciatic nerve of male rats was crushed in accordance with a standardized method. To investigate the positive influence of different substances on nerve regeneration, the rats received daily injections of alpha-liponic acid, vitamin B or gangliosides. After 11 days the sciatic nerves were removed and the area distal to the crush site was analyzed histomorphometrically. Compared with the control group, there was only a slight increase in the number of regenerating fibres and their diameters following treatment with alpha-liponic acid or vitamin B. However, in the ganglioside-treated rats the differences, indicative of accelerated regeneration, were statistically significant.

  19. COMPARATIVE STUDIES OF HERPETOMONADS AND LEISHMANIAS

    PubMed Central

    Noguchi, Hideyo

    1926-01-01

    . culicidarum. This organism ferments thirteen sugars, including amygdalin which no other organism of the series attacks. One of the most striking phenomena observed was the entire lack of fermentative faculty on the part of Herpetomonas ctenocephali and Trypanosoma rotatorium. Neither of these organisms was affected by any of the immune sera prepared with other flagellates. The serological specificity of Leishmania tropica, L. brasiliensis, and L. donovani, and the close relation between L. donovani and L. infantum were confirmed in the present study. These organisms could not, however, be differentiated by fermentation tests. The data presented suggest that the biological characteristics of flagellates of the Herpetomonas group may be utilized with advantage for identification of a species which occurs in different environments and for separation of different species when they are found in the same environment. If the leishmania parasites pass the flagellated or herpetomonad stage of their life history in some invertebrate host, it may be possible by tests of the sort described to distinguish them from the non-pathogenic herpetomonads which are so widely distributed among insects and plants. PMID:19869187

  20. Comparative Study of Morphometric and Fourier Transform Infrared Spectroscopy Analyses of the Collagen Fibers in the Repair Process of Cutaneous Lesions

    PubMed Central

    Nogueira, Veruska Cronemberger; Raniero, Leandro; Costa, Guilherme Bueno; de Freitas Coelho, Nayana Pinheiro Machado; Miranda, Fernando Cronemberger; Arisawa, Emília Ângela Loschiavo

    2016-01-01

    Objective: Compare the efficacy of light-emitting diode (LED) and therapeutic ultrasound (TUS), combined with a semipermeable dressing (D), at forming collagen in skin lesions by morphometry and Fourier transform infrared spectroscopy (FT-IR). Materials and Methods: Surgical skin wounds (2.5 cm) were created on 84 male Wistar rats divided into four groups (n=21): Group I (Control), Group II (LED), Group III (LED+D), and Group IV (US+D). On days 7, 14, and 21, the tissue samples were removed and divided into two pieces, one was used for histological examination (collagen) and the other for FT-IR. Results: The histomorphometric analysis showed no significant differences among groups for collagen deposition at 7 days. However, at 14 days, more deposition of collagen was noted in the groups LED (p<0.05) and LED+D (p<0.001) than in the control. At 21 days, the groups LED, LED+D, and US+D presented significantly greater deposition of collagen when compared with the control. The FT-IR spectra, at 14 days, LED+D had greater amounts of type I collagen, a better organization of fibers, and greater difference of mean separation between the groups, not observed at 7 and 21 days. Innovation: The histomorphometric and FT-IR analyses suggest that the association of semipermeable dressing to LED therapy and to TUS modulates biological events, increasing fibroblast/collagen response and accelerating dermal maturation. Conclusion: The histomorphometric and FT-IR analyses showed that LED therapy is more efficacious than TUS, when combined with a semipermeable dressing, and induced the collagen production in skin lesions. PMID:26862463

  1. Comparative mirror cleaning study: a study on removing particulate contamination

    NASA Astrophysics Data System (ADS)

    Houston, Karrie D.

    2006-08-01

    A mirror cleaning study was conducted to assess the effectiveness of three cleaning methods in their ability to remove particulate contamination from reflective mirror surfaces. Presently, the detergent bath, solvent rinse, and CO II snow cleaning methods are the most commonly used optical cleaning techniques within the optics industry. These techniques are also commonly used by the Optics Branch/Code 551 at Goddard Space Flight Center (GSFC) to remove particulate contamination from optical surfaces. In this experimental study, the above-mentioned cleaning methods were used to clean twelve uncoated silicon wafers, twelve gold coated silicon wafers, and twelve gold coated silicon wafers with a silicon oxide protective coating. CO II snow cleaning had an average removal percentage of 84%, followed by the solvent rinse at 74%, and the detergent bath at 61%. In addition to the average removal percentage, this comparative study was designed to: (1) determine the cleaning ability of each method based on the number and size of removed particles; (2) assess the risk of surface damage for each cleaning procedure; (3) evaluate each cleaning method as a function of its initial "qualitative" contamination level ("fairly clean", "dirty", and "very dirty"). The particulate cleanliness of all wafers was characterized using Image Analysis and Image-Pro Plus 5.0 software. In addition, the experimental design and experimental results were analyzed using JMP/Statistical Analytical Software Version 6.0.

  2. Histopathological, histomorphometrical, and immunohistochemical biomarkers in flounder (Platichthys flesus) from the southern Baltic Sea.

    PubMed

    Dabrowska, Henryka; Ostaszewska, Teresa; Kamaszewski, Maciej; Antoniak, Agnieszka; Napora-Rutkowski, Lukasz; Kopko, Orest; Lang, Thomas; Fricke, Nicolai F; Lehtonen, Kari K

    2012-04-01

    Flounder (Platichthys flesus), collected in late fall of 2009 from four coastal sites in the southern Baltic Sea including the Gulf of Gdańsk (GoG), were investigated for a suite of biomarkers of contaminant effects. The biomarkers included liver histopathologies, which were diagnosed and assessed using commonly applied lesion categories, the size and density of melano-macrophage aggregates (MMAs), expression of proliferating cell nuclear antigen (PCNA) and of cytochrome P450 1A (CYP1A) in liver as well as the size and density of MMAs and density of Perls'-positive cells in the spleen. The prevalence of liver lesions differed among the sites. Most frequently occurring were non-specific and early toxicopathic non-neoplastic lesions. Mean MMA size was in the range of 264-519 μm(2) and 717-2137 μm(2) in liver and spleen, respectively, and density was in the range of 6-13 and 15-26 MMAmm(-2), respectively. Mean density of PCNA-positive hepatocytes was in the range of 300-1281 cellsmm(-2). These histomorphometrical biomarkers correlated positively with the muscle Hg, Σ(7)PCB, and ΣDDT residues and negatively with the indices of general liver condition. They showed significant differences between the sites, which were in line with the spatial prevalence of liver lesions and CYP1A induction. Overall, the biomarker responses were more pronounced in the GoG sites in comparison to those outside the Gulf, which confirms some earlier results and broadens the knowledge of contaminant effects in the Polish coastal zone of the Baltic Sea.

  3. What Do We Compare When We Compare Religions? Philosophical Remarks on the Psychology of Studying Comparative Religion Abroad

    ERIC Educational Resources Information Center

    Irvine, Andrew

    2015-01-01

    The issue of comparison is a vexing one in religious and theological studies, not least for teachers of comparative religion in study abroad settings. We try to make familiar ideas fresh and strange, in settings where students may find it hard not to take "fresh" and "strange" as signs of existential threat. The author explores…

  4. A comparative study of the bone metabolic response to dried plum supplementation and PTH treatment in adult, osteopenic ovariectomized rat.

    PubMed

    Smith, Brenda J; Bu, So Young; Wang, Yan; Rendina, Elizabeth; Lim, Yin F; Marlow, Denver; Clarke, Stephen L; Cullen, Diane M; Lucas, Edralin A

    2014-01-01

    Dried plum has been reported to have potent effects on bone in osteopenic animal models, but the mechanisms through which bone metabolism is altered in vivo remain unclear. To address this issue, a study comparing the metabolic response of dried plum to the anabolic agent, parathyroid hormone (PTH), was undertaken. Six month-old female Sprague Dawley rats (n=84) were sham-operated (SHAM) or ovariectomized (OVX) and maintained on a control diet for 6wks until osteopenia was confirmed. Treatments were initiated consisting of a control diet (AIN-93M) supplemented with dried plum (0, 5, 15 or 25%; w/w) or a positive control group receiving PTH. At the end of 6wks of treatment, whole body and femoral bone mineral density (BMD) were restored by the two higher doses of dried plum to the level of the SHAM group. Trabecular bone volume and cortical thickness were also improved with these two doses of dried plum. Dried plum suppressed the OVX-induced increase in bone turnover as indicated by systemic biomarkers of bone metabolism, N-terminal procollagen type 1 (P1NP) and deoxypyridinoline (DPD). Dynamic bone histomorphometric analysis of the tibial metaphysis revealed that dried plum restored the OVX-induced increase in cancellous bone formation rate (BFR) and mineralizing surface (MS/BS) to the SHAM group, but some doses of dried plum increased endocortical mineral apposition rate (MAR). As expected, PTH significantly increased endocortical MAR and BFR, periosteal BFR, and trabecular MAR and BFR beyond that of the OVX and maintained the accelerated rate of bone resorption associated with OVX. Dried plum up-regulated bone morphogenetic protein 4 (Bmp4) and insulin-like growth factor 1 (Igf1) while down-regulating nuclear factor T cell activator 1 (Nfatc1). These findings demonstrate that in the adult osteopenic OVX animal, the effects of dried plum differ from that of PTH in that dried plum primarily suppressed bone turnover with the exception of the indices of bone

  5. Analysis of new bone, cartilage, and fibrosis tissue in healing murine allografts using whole slide imaging and a new automated histomorphometric algorithm

    PubMed Central

    Zhang, Longze; Chang, Martin; Beck, Christopher A; Schwarz, Edward M; Boyce, Brendan F

    2016-01-01

    Histomorphometric analysis of histologic sections of normal and diseased bone samples, such as healing allografts and fractures, is widely used in bone research. However, the utility of traditional semi-automated methods is limited because they are labor-intensive and can have high interobserver variability depending upon the parameters being assessed, and primary data cannot be re-analyzed automatically. Automated histomorphometry has long been recognized as a solution for these issues, and recently has become more feasible with the development of digital whole slide imaging and computerized image analysis systems that can interact with digital slides. Here, we describe the development and validation of an automated application (algorithm) using Visiopharm’s image analysis system to quantify newly formed bone, cartilage, and fibrous tissue in healing murine femoral allografts in high-quality digital images of H&E/alcian blue-stained decalcified histologic sections. To validate this algorithm, we compared the results obtained independently using OsteoMeasureTM and Visiopharm image analysis systems. The intraclass correlation coefficient between Visiopharm and OsteoMeasure was very close to one for all tissue elements tested, indicating nearly perfect reproducibility across methods. This new algorithm represents an accurate and labor-efficient method to quantify bone, cartilage, and fibrous tissue in healing mouse allografts. PMID:26816658

  6. [Comparative Migration Studies and Comparative Politics.] Fulbright-Hays Summer Seminars Abroad, 1997 (India).

    ERIC Educational Resources Information Center

    Ireland, Patrick

    This paper addresses how the experience of the Fulbright Seminar in India has allowed the participant to enrich his teaching in comparative migration studies and comparative politics. The paper describes specifically how each course has changed as a result of the international experience. The report suggests questions for consideration as the…

  7. Histopathological, Histomorphometrical, and Radiographical Evaluation of Injectable Glass-Ceramic-Chitosan Nanocomposite in Bone Reconstruction of Rat

    PubMed Central

    Seyedmajidi, Maryam; Rabiee, Seyedmahmood; Haghanifar, Sina; Seyedmajidi, Seyedkamal; Jorsaraei, Seyed Gholam ali; Alaghehmand, Homayoun; Jamaatlu, Naghmeh; Bijani, Ali

    2015-01-01

    Background. Bone defects following tumor resection and osteolysis due to bone lesions, periodontal tissue disorders, and bone reconstruction are challenges that surgeons face. Gass-ceramic-chitosan nanocomposite contains chitosan, a derivative of crustaceans' exoskeleton. Methods. Thirty-two 6–8-week-old male Wistar rats were chosen. One hole on each right and left tibia was made. The right tibia holes were filled with injectable glass-ceramic-chitosan nanocomposite, and the left tibia holes were left empty. After 7, 14, 28, and 60 days, histopathological, histomorphometrical, and radiographical assessments were performed. Results. Radiographic density on days 7 and 14 was significantly higher in the right tibias than in the left tibias. Trabecular bone thickness, which was higher in the right tibias, increased from day 7 to day 60 in both right and left tibias, although not significantly. Conclusions. Glass-ceramic-chitosan nanocomposite is suggested for use in bone repair in cases of bone loss. More histopathological, histomorphometrical, and radiographical assessments are also recommended. PMID:25737725

  8. Technology-Enhanced Consultation in Counselling: A Comparative Study

    ERIC Educational Resources Information Center

    Astramovich, Randall L.; Jones, W. Paul; Coker, J. Kelly

    2004-01-01

    Two quasi-experimental studies comparing technology-enhanced counselling consultation were conducted with a sample of 147 students enrolled in an undergraduate counselling and consultation course for elementary and secondary teachers. Study 1 (N = 76) compared the effectiveness of counselling consultation using telephone, text chat, or text chat…

  9. Global Harmonization of Comparator Products for Bioequivalence Studies.

    PubMed

    Gwaza, Luther; Gordon, John; Leufkens, Hubert; Stahl, Matthias; García-Arieta, Alfredo

    2017-03-06

    Comparator products should be the products that were shown to be safe and efficacious in pivotal clinical trials to ensure prescribability of generics. The use of a common comparator ensures switchability between generics. The selection of the comparator is a national responsibility and may be different between countries. This paper discusses the current recommendations on selection of comparators, the associated problems, and the possibility of harmonization. Most countries follow the World Health Organization (WHO) recommendations for selecting comparator products and require the comparator product to be obtained from their national markets to ensure switchability between the local comparator and their generics. These recommendations are only feasible in the few countries where the repetition of the bioequivalence study is economically feasible, but they are impracticable in all other countries. Furthermore, the exclusive use of the local comparator to ensure switchability is ethically and scientifically questionable. The innovator product from well-regulated markets should be the global comparator. This harmonization is feasible as the concept already applies in the WHO prequalification program. It is ineffectual to harmonize only the requirements for performing bioequivalence studies, if such a study has to be repeated for every single country simply because of the different comparator products.

  10. Growth characteristics underlying lack of a chin in pigs: a histomorphometric study

    PubMed Central

    Price, J.; Tee, B. C.; Vig, K.; Shanker, S.; Kennedy, K.; Sun, Z.

    2015-01-01

    Objectives Despite similar mandibular growth to that of humans, pigs lack a chin projection as shown in most humans. To understand whether this divergence is contributed to differences in local symphyseal growth, this project characterized bone modeling activities at the symphyseal surfaces of juvenile pigs. Material and Methods Symphyseal specimens from 2 age groups (4- and 6-month-old, n=10) were processed into histological sections with and without decalcification, which were assessed for surface mineral apposition and bone resorption, respectively. In a blinded fashion, measurements of four parameters (MAR: mineral apposition rate, MAZ: mineral apposition zone; ES/BS: eroded surface; OC.N/BS: osteoclast number) were obtained and tested by a multivariate two-way mixed-model analyses of variance (MANOVA) for the differences between symphyseal regions and ages. Results Qualitatively, pig symphyseal labial and lingual surfaces were horizontally oriented and characterized by mineral apposition and bone resorption, respectively. Quantitatively, labial mineral apposition tended to be greater rostrally than caudally at 4 months, which became greater caudally than rostrally at 6 months (region/age interactions: p=0.127 for MAR, p=0.012 for MAZ). Lingual bone resorption tended to be greater caudally than rostrally, but only ES/BS measurements was significant (p=0.039) regardless of age while OC.N/BS measurements varied with ages and regions (age/region interaction, p=0.087). Conclusions Insufficient differential in symphyseal surface modeling between the labial-caudal and labial-rostral regions contributes to the lack of chin projection in the pig. PMID:26250613

  11. Are comparative studies of extinction risk useful for conservation?

    PubMed

    Cardillo, Marcel; Meijaard, Erik

    2012-03-01

    Large-scale, comparative studies of species extinction risk have become common in conservation science, but their influence on conservation practice appears limited. The link between such studies and the practice of conservation breaks down in two key places. First, results of comparative studies are often ambiguous, inconsistent and difficult to translate into policy. Second, conservation as currently practiced emphasizes the rescue and protection of currently threatened biodiversity, whereas comparative studies are often better suited to a proactive approach that anticipates and prevents future species declines. Scientists should make their research more accessible by addressing the first issue. Policymakers and managers, in turn, could make better use of comparative studies by moving towards more preventative approaches to conservation planning.

  12. From Comparative Education to Comparative Pedagogy: A Physical Education Case Study

    ERIC Educational Resources Information Center

    Georgakis, Steve; Graham, Jessica

    2016-01-01

    In the last two decades forces of globalization and the rise of and access to information technology have transformed the nature of educational research. Traditional disciplines such as comparative education have not been immune to these transformational impacts. Although one might expect globalization to promote the study of comparative…

  13. Comparative Mirror Cleaning Study: 'A Study on Removing Particulate Contamination'

    NASA Technical Reports Server (NTRS)

    Houston, Karrie

    2007-01-01

    The cleanliness of optical surfaces is recognized as an industry-wide concern for the performance of optical devices such as mirrors and telescopes, microscopes and lenses, lasers and interferometers, and prisms and optical filters. However, no standard has been established for optical cleaning and there is no standard definition of a 'clean' optical element. This study evaluates the effectiveness of commonly used optical cleaning techniques based on wafer configuration, contamination levels, and the number and size of removed particles. It is concluded that cleaning method and exposure time play a significant factor in obtaining a high removal percentage. The detergent bath and solvent rinse method displayed an increase in effective removal percentage as the contamination exposure increased. Likewise, CO2 snow cleaning showed a relatively consistent cleaning effectiveness. The results can help ensure mission success to flight projects developed for the NASA Origins Program. Advantages and disadvantages of each of the optical cleaning methods are described.

  14. A Comparative Study of Croatian and Hungarian EFL Students

    ERIC Educational Resources Information Center

    Mihaljevic Djigunovic, Jelena; Nikolov, Marianne; Otto, Istvan

    2008-01-01

    This comparative research aims to provide insights into how Croatian and Hungarian 8th graders' proficiency in English as a foreign language (EFL) compares to one another in relation to organizational macro factors. A total of 717 14-year-old students participated in the study in two neighboring regions and towns of Croatia and Hungary examining…

  15. Important Questions of Comparative Studies in Asian Countries

    ERIC Educational Resources Information Center

    Pazyura, Natalia

    2015-01-01

    The issue of the "identity" of comparative education as a field of study or a discipline has been discussed for decades. Yet a kind of systematic structure that provides the basic principles for a coherent exposition of the field remains open. "Comparative education" is no longer conceived as an imaginary field's coherence but,…

  16. Mobile Learning vs. Traditional Classroom Lessons: A Comparative Study

    ERIC Educational Resources Information Center

    Furió, D.; Juan, M.-C.; Seguí, I.; Vivó, R.

    2015-01-01

    Different methods can be used for learning, and they can be compared in several aspects, especially those related to learning outcomes. In this paper, we present a study in order to compare the learning effectiveness and satisfaction of children using an iPhone game for learning the water cycle vs. the traditional classroom lesson. The iPhone game…

  17. Melatonin as a pro-osteogenic agent in oral implantology: a systematic review of histomorphometric outcomes in animals and quality evaluation using ARRIVE guidelines.

    PubMed

    Arora, H; Ivanovski, S

    2017-04-01

    The aim of this review was to evaluate the outcomes of preclinical trials that assessed the use of melatonin as a pro-osteogenic agent in the field of oral implantology. Melatonin is a hormone that has been shown to have beneficial antioxidant and bone-metabolic effects. A number of experimental studies have analysed its effect in promoting osseointegration around dental implants in animals. A bibliographic search in PubMed, Scopus and EBSCOhost was performed. Animal studies that quantitatively analysed the pro-osteogenic effect of melatonin were included. Quality assessment of the included studies was performed using the ARRIVE guidelines. Eight studies met the inclusion criteria. The experimental animals used were dogs, rabbits and rats. Melatonin was used in a lyophilized powdered form, an injectable form or as a dipping solution. Six of the eight studies included showed a statistically significant positive effect of melatonin on bone-implant contact and various other histomorphometric parameters. The ARRIVE criteria were generally well reported by the included studies (17.5 ± 1.60/24), although several criteria (including randomization and blinding) were poorly documented, with most of the studies showing a high/unclear risk of bias. The majority of the studies included showed a statistically significant positive effect of melatonin on bone formation around implants. However, the clinical significance of this effect was unclear given the high/unclear risk of bias in the majority of included studies. Given the limited amount of data available, further research should be conducted to evaluate the clinical potential of this pineal hormone in clinically relevant situations, such as compromised sites or patients.

  18. Teacher Leader Human Relations Skills: A Comparative Study

    ERIC Educational Resources Information Center

    Roby, Douglas E.

    2012-01-01

    In this study, 142 graduate school teachers working in schools throughout southwestern Ohio assessed their human relation skills. A human relations survey was used for the study, and results were compared with colleagues assessing the teachers in the study. The survey was developed using a Likert-type scale, and was based on key elements affecting…

  19. Male and Female High School Principals: A Comparative Study.

    ERIC Educational Resources Information Center

    Paddock, Susan C.

    Differences in the personal and career characteristics of men and women secondary principals were examined by comparing data from a study of women high school principals with data from a National Association of Secondary School Principals (NASSP) study on the secondary school principalship. Data for the study of women principals were provided by…

  20. Information Technology Diffusion: A Comparative Case Study of Intranet Adoption

    DTIC Science & Technology

    1999-07-01

    Information Technology Diffusion: A Comparative Case Study of Intranet Adoption George A. Zolla Jr. Naval Postgraduate School, Monterey, CA 93943...unfreezing”. Cooper and Zmud [4] defined IT implementation as “an organizational effort directed toward diffusing appropriate information technology within a...1999 4. TITLE AND SUBTITLE Information Technology Diffusion: A Comparative Case Study of Intranet Adoption 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  1. A comparative study of centbucridine and lidocaine in dental extraction.

    PubMed

    Vacharajani, G N; Parikh, N; Paul, T; Satoskar, R S

    1983-01-01

    A randomized double-blind study comparing the efficacy and tolerability of centbucridine (0.5%) with those of lidocaine (2%) as an anaesthetic agent was conducted in the dental outpatient department on patients attending for dental extraction. One hundred and twenty patients were studied. The degree of analgesia attained with centbucridine compared well with that obtained with lidocaine. The compound was well tolerated with no significant changes in the cardiovascular parameters and no serious side-effects.

  2. Comparative studies on the skeletogenic mesenchyme of echinoids.

    PubMed

    Minokawa, Takuya

    2016-11-14

    Skeletogenic mesenchyme cells in echinoids are suitable for studying developmental mechanisms, and have been used extensively. Most of these studies have been performed on species in the order Camarodonta, which are modern echinoids (subclass Euechinoidea) and are considered "model" echinoid species. In contrast, species belonging to other orders are studied less frequently, especially investigations of their molecular developmental biology such as gene regulatory networks. Recent studies on mesenchyme development in non-camarodont species suggest that these species are potential sources of comparative information to elucidate the mechanisms underlying skeletogenic mesenchyme development. In this review, the importance of using comparative data to understand development and evolution is discussed.

  3. Comparative Study of Bio-implantable Acoustic Generator Architectures

    NASA Astrophysics Data System (ADS)

    Christensen, D.; Roundy, S.

    2013-12-01

    This paper is a comparative study of the design spaces of two bio-implantable acoustically excited generator architectures: the thickness-stretch-mode circular piezoelectric plate and the bending-mode unimorph piezoelectric diaphragm. The generators are part of an acoustic power transfer system for implanted sensors and medical devices such as glucose monitors, metabolic monitors, drug delivery systems, etc. Our studies indicate that at small sizes the diaphragm architecture outperforms the plate architecture. This paper will present the results of simulation studies and initial experiments that explore the characteristics of the two architectures and compare their performance.

  4. Political Ideology: A Comparative Study of Three Chicano Youth Organizations.

    ERIC Educational Resources Information Center

    Garcia, Richard A.

    The study investigated the political ideology of three Chicano youth groups in El Paso, Texas: Mexican American Youth Association (MAYA), Mexican American Political Association (MAPA), and the Alianza. Purpose of the study was to identify and compare the political ideas and attitudes of the three organizations. Questionnaires were administered to…

  5. Living With and Learning about Radioactivity: A Comparative Conceptual Study.

    ERIC Educational Resources Information Center

    Alsop, Steve

    2001-01-01

    Documents a quasi-scientific comparative study of two groups of 'recent school leavers' in the UK. Studies non-science university undergraduates and explores whether people living with the immediacy and relevance of higher-than-average levels of radioactivity were more knowledgeable and emotionally detached than a similar group removed from this…

  6. A Comparative Study of Teaching Typing Skills on Microcomputers.

    ERIC Educational Resources Information Center

    Lindsay, Robert M.

    A 4-week experimental study was conducted with 105 high school students in 4 introductory typewriting classes of a large urban school in British Columbia during the 1981 spring semester. The purpose of the study was to compare the effectiveness of teaching the skill-building components of typewriting speed and accuracy using either the…

  7. Entrepreneurial Training: A Comparative Study across Fifteen European Countries

    ERIC Educational Resources Information Center

    Matricano, Diego

    2014-01-01

    This paper arises from the contents of the Lisbon Strategy, a set of cooperation policies stressing the role of education and training. The findings from a comparative study of the influence that entrepreneurial training--classified as formal or informal--can have on start-up expectations are analysed. The study covers fifteen European countries…

  8. Sustainability of Social Programs: A Comparative Case Study Analysis

    ERIC Educational Resources Information Center

    Savaya, Riki; Spiro, Shimon; Elran-Barak, Roni

    2008-01-01

    The article reports on the findings of a comparative case study of six projects that operated in Israel between 1980 and 2000. The study findings identify characteristics of the programs, the host organizations, and the social and political environment, which differentiated programs that are sustained from those that are not. The findings reaffirm…

  9. A Comparative Study of Students' Achievement in Botany and Zoology

    ERIC Educational Resources Information Center

    Tamir, P.

    1974-01-01

    A comparative study of student achievement in botany and zoology based on data of 10 studies conducted in 20 countries. Up to age 14, students achieve better in zoology; after age 14, students achieve better in botany. Based on the findings, recommendations are suggested regarding curriculum planning, laboratory work and the need for specific…

  10. Comparative genomics approaches to study organism similarities and differences

    SciTech Connect

    Wei, Liping; Liu, Yueyi; Dubchak, Inna; Shon, John; Park, John

    2002-06-01

    Comparative genomics is a large-scale, holistic approach that compares two or more genomes to discover the similarities and differences between the genomes and to study the biology of the individual genomes. Comparative studies can be performed at different levels of the genomes to obtain multiple perspectives about the organisms. We discuss in detail the type of analyses that offer significant biological insights in the comparisons of (1) genome structure including overall genome statistics, repeats, genome rearrangement at both DNA and gene level, synteny, and breakpoints; (2) coding regions including gene content, protein content, orthologs, and paralogs; and (3) noncoding regions including the prediction of regulatory elements. We also briefly review the currently available computational tools in comparative genomics such as algorithms for genome-scale sequence alignment, gene identification, and nonhomology-based function prediction.

  11. A comparative study between shielded and open coplanar waveguide discontinuities

    NASA Technical Reports Server (NTRS)

    Dib, Nihad I.; Harokopus, W. P., Jr.; Ponchak, G. E.; Katehi, L. P. B.

    1993-01-01

    A comparative study between open and shielded coplanar waveguide (CPW) discontinuities is presented. The space domain integral equation method is used to characterize several discontinuities such as the open-end CPW and CPW series stubs. Two different geometries of CPW series stubs (straight and bent stubs) are compared with respect to resonant frequency and radiation loss. In addition, the encountered radiation loss due to different CPW shunt stubs is evaluated experimentally. The notion of forced radiation simulation is presented, and the results of such a simulation are compared to the actual radiation loss obtained rigorously. It is shown that such a simulation cannot give reliable results concerning radiation loss from printed circuits.

  12. Diagnosis of bone metastasis: recent comparative studies of imaging modalities.

    PubMed

    Talbot, J N; Paycha, F; Balogova, S

    2011-08-01

    Various imaging modalities are currently available to diagnose bone metastasis. The two main anatomical modalities are computed tomography (CT) and magnetic resonance imaging (MRI), with many variants proposed for the MRI procedure, including diffusion-weighted imaging. The two main functional modalities are scintigraphy and PET, also with many variants in the radiopharmaceutical, from the "all purpose" 99mTc labelled bisphosphonates to very selective radiopharmaceuticals for rare neoplasia. The diagnostic strategy will become more and more individually tailored according to the patient's clinical and biological data (primary cancer type, phase of the evolution, markers of aggressiveness, serum levels of biological tracers of bone metabolism, circulating or disseminating tumour cells …). If imaging is indicated, the diagnostic strategy will also depend on the availability and the diagnostic performance of the imaging modalities. Assessment of diagnostic performance requires comparative studies, performed with an adequate methodology. The main methodological weaknesses encountered in studies intending to compare imaging modalities for diagnosing bone metastasis are summarised. Comparative studies have been reviewed, which address the initial diagnosis of skeletal metastases in solid tumours except primary bone cancers. The results of more than 140 such comparative studies are then summarised and briefly commented, according to the type of the primary cancer, and according to the compared imaging modalities.

  13. "Lies, damned lies ..." and observational studies in comparative effectiveness research.

    PubMed

    Albert, Richard K

    2013-06-01

    A new federal initiative has allocated $1.1 billion to comparative effectiveness research, and many have emphasized the importance of including observational studies in this effort. The rationale for using observational studies to assess comparative effectiveness is based on concerns that randomized controlled trials (RCTs) are not "real world" because they enroll homogeneous patient populations, measure study outcomes that are not important to patients, use protocols that are overly complex, are conducted in specialized centers, and use study treatments that are not consistent with usual care, and that RCTs are not always feasible because of a lack of equipoise, the need to assess delayed endpoints, and concerns that they take years to complete and are expensive. This essay questions the validity of each of these proposed limitations, summarizes concerns raised about the accuracy of results generated by observational studies, provides some examples of discrepancies between results of observational studies and RCTs that pertain to pulmonary and critical care, and suggests that using observational studies for comparative effectiveness research may increase rather than decrease the cost of health care and may harm patients.

  14. Reverse engineering of gene regulatory networks: a comparative study.

    PubMed

    Hache, Hendrik; Lehrach, Hans; Herwig, Ralf

    2009-01-01

    Reverse engineering of gene regulatory networks has been an intensively studied topic in bioinformatics since it constitutes an intermediate step from explorative to causative gene expression analysis. Many methods have been proposed through recent years leading to a wide range of mathematical approaches. In practice, different mathematical approaches will generate different resulting network structures, thus, it is very important for users to assess the performance of these algorithms. We have conducted a comparative study with six different reverse engineering methods, including relevance networks, neural networks, and Bayesian networks. Our approach consists of the generation of defined benchmark data, the analysis of these data with the different methods, and the assessment of algorithmic performances by statistical analyses. Performance was judged by network size and noise levels. The results of the comparative study highlight the neural network approach as best performing method among those under study.

  15. Comparative and Developmental Study of the Immune System in Xenopus

    PubMed Central

    Robert, Jacques; Ohta, Yuko

    2010-01-01

    Xenopus laevis is the model of choice for evolutionary, comparative, and developmental studies of immunity, and invaluable research tools including MHC-defined clones, inbred strains, cell lines, and monoclonal antibodies are available for these studies. Recent efforts to use Silurana (Xenopus) tropicalis for genetic analyses have led to the sequencing of the whole genome. Ongoing genome mapping and mutagenesis studies will provide a new dimension to the study of immunity. Here we review what is known about the immune system of X. laevis integrated with available genomic information from S. tropicalis. This review provides compelling evidence for the high degree of similarity and evolutionary conservation between Xenopus and mammalian immune systems. We propose to build a powerful and innovative comparative biomedical model based on modern genetic technologies that takes take advantage of X. laevis and S. tropicalis, as well as the whole Xenopus genus. PMID:19253402

  16. Generation 1.5 Written Error Patterns: A Comparative Study

    ERIC Educational Resources Information Center

    Doolan, Stephen M.; Miller, Donald

    2012-01-01

    In an attempt to contribute to existing research on Generation 1.5 students, the current study uses quantitative and qualitative methods to compare error patterns in a corpus of Generation 1.5, L1, and L2 community college student writing. This error analysis provides one important way to determine if error patterns in Generation 1.5 student…

  17. Comparative Studies on Sino-Canadian Higher Education

    ERIC Educational Resources Information Center

    Yang, Hong

    2008-01-01

    Today education is internationalization. Both China and Canada have their own strong merits of higher education. This paper approaches comparative studies on differences of Sino-Canadian higher education from new points, so as to achieve an inspiration to the development of Chinese higher education: preserve relative independence between higher…

  18. A Comparative Study of the Adjustment of Secondary School Students

    ERIC Educational Resources Information Center

    Devika R.

    2014-01-01

    Education is the ability to meet one's life. How the child adjusts with varying situations determines the success of life. The child's adjustment is determined by a number of factors like Home, Social, Educational and Financial adjustment. The investigator here aims to make a comparative study on the adjustment of secondary school students. The…

  19. A Comparative Study of Two Acoustic Measures of Hypernasality

    ERIC Educational Resources Information Center

    Vogel, Adam P.; Ibrahim, Hasherah M.; Reilly, Sheena; Kilpatrick, Nicky

    2009-01-01

    Purpose: This study aimed to compare 2 quantitative acoustic measures of nasality in children with cleft lip and palate (CLP) and healthy controls using formalized perceptual assessment as a guide. Method: Fifty participants (23 children with CLP and 27 age- and gender-matched healthy controls) aged between 4 and 12 years produced a variety of…

  20. Midlife Women in Continuing Education: A Comparative Study.

    ERIC Educational Resources Information Center

    Traupmann, Jane

    Developmental theorists have suggested recently that at midlife women often want to reduce responsibilities to family and concentrate on self-development and growth, which earlier in their lives would have seemed to them selfish and therefore not acceptable. The aim of this comparative study was to determine if women returning to school at midlife…

  1. Different Underlying Neurocognitive Deficits in Developmental Dyslexia: A Comparative Study

    ERIC Educational Resources Information Center

    Menghini, D.; Finzi, A.; Benassi, M.; Bolzani, R.; Facoetti, A.; Giovagnoli, S.; Ruffino, M.; Vicari, S.

    2010-01-01

    The aim of this study was to investigate the role of several specific neurocognitive functions in developmental dyslexia (DD). The performances of 60 dyslexic children and 65 age-matched normally reading children were compared on tests of phonological abilities, visual processing, selective and sustained attention, implicit learning, and executive…

  2. Research Governance and the Role of Evaluation: A Comparative Study

    ERIC Educational Resources Information Center

    Molas-Gallart, Jordi

    2012-01-01

    Through a comparative study of the United Kingdom and Spain, this article addresses the effect of different research governance structures on the functioning and uses of research evaluation. It distinguishes three main evaluation uses: distributive, improvement, and controlling. Research evaluation in the United Kingdom plays important…

  3. Comparative Study of Student Support Services of AIOU and UKOU

    ERIC Educational Resources Information Center

    Choudhry, Amtul Hafeez; Gujjar, Aijaz Ahmed; Hafeez, Muhammad Rashid

    2008-01-01

    This paper attempts to compare the availability, quality, similarities and differences of student support services in Allama Iqbal Open University (AIOU) and United Kingdom Open University (UKOU) and also to identify and enlist the deficiencies that AIOU students are facing in the student support services. The study found out that student support…

  4. Using Comparative Online Media to Study the Iraq War

    ERIC Educational Resources Information Center

    Eaton, Jana Sackman

    2004-01-01

    The war in Iraq and the aftermath are receiving media attention around the globe. A plethora of media reports from many other countries is now available online in English. This article recommends possible approaches to developing comparative media studies and provides URLs to specific sources. The NCSS standards addressed by these lessons include:…

  5. A Comparative Study of Students' Attitudes Toward Education.

    ERIC Educational Resources Information Center

    Quintanar, Rosalinda

    The comparative analysis of students' attitudes included Mexican American, Anglo, and Asian students (from Thailand, Taiwan, and the Philippines). A Likert scale was used to measure all attitudes. All analysis performed utilized cross tabulation and chi square. The attitudes studied were reasons for going to college; concept of an educated person…

  6. The Social Sciences and the Comparative Study of Educational Systems.

    ERIC Educational Resources Information Center

    Fischer, Joseph, Ed.

    Aiming at the comprehension of schools as social, political, economic, and cultural systems, this book suggests that education does not constitute a separate academic discipline but is dependent upon the social sciences for its elucidation and for its comparative study. The book emphasizes interdisciplinary approaches within four social sciences…

  7. Comparative Study of Bacterial Growth in Magnet Fields

    NASA Astrophysics Data System (ADS)

    Smith, Derek; Masood, Samina

    It has been shown that magnetic fields affect bacterial growth. A comparative study of growth rates for gram-positive and gram-negative bacteria with different types of magnetic fields is done. Special focus is placed upon growth within liquid media, and the effect of magnetic fields relative to the chosen growth medium is considered.

  8. Homeless Adolescents' Perceptions of Positive Development: A Comparative Study

    ERIC Educational Resources Information Center

    Nott, Brooke Dolenc; Vuchinich, Samuel

    2016-01-01

    Background: While some recent research has addressed homeless youth from a strengths-based approach, comparative studies of homeless and non-homeless youth from a strengths perspective are few; research that includes youth's views on positive youth development are also limited. Objective: Addressing these gaps and using an inductive approach,…

  9. Peri-implant bone tissues around retrieved human implants after time periods longer than 5 years: a retrospective histologic and histomorphometric evaluation of 8 cases.

    PubMed

    Iezzi, Giovanna; Piattelli, Adriano; Mangano, Carlo; Shibli, Jamil A; Vantaggiato, Giovanni; Frosecchi, Massimo; Di Chiara, Claudio; Perrotti, Vittoria

    2014-01-01

    Only rarely, it is possible to find in the literature histological reports of human retrieved implants, especially after several years of functional loading. These implants can help us in understanding the reactions of peri-implant bone. The aim of this study was to perform a histologic and histomorphometric analysis of the peri-implant tissues behavior and of the bone-titanium interface in titanium dental implants retrieved from patients after time periods longer than 5 years. The archives of the Implant Retrieval Center of the Dental School of the University of Chieti-Pescara, Italy were searched for human dental implants, retrieved after a loading period of more than 5 years. A total of 8 implants were found: 3 of these had been retrieved after 5 years, 1 after 6 years, one after 10 years, 1 after 14 years, 1 after 18 years, 1 after 22 years. Only the bone to implant contact in the three best threads was evaluated. Compact, mature, lamellar bone, with few and small marrow spaces, was present around the implants. Osteons with Haversian canals were present inside some threads, in close proximity to the interface, at both cortical and trabecular regions. Other osteons had a direction perpendicular to the direction of the long axis of the implants. Numerous reversal lines were present. At higher magnification, no gaps or fibrous, connective tissues were present at the interface. The BIC of the three best threads for all implants varied from 94 to 100 %.In conclusion, within the limitations of the present report histology showed that implants with different surfaces all presented the potential to maintain osseointegration over a long period, with a continuous remodeling at the interface, as indicated by the presence of reversal lines.

  10. Bone response to dental implants after a 3- to 10-year loading period: a histologic and histomorphometric report of four cases.

    PubMed

    Iezzi, Giovanna; Degidi, Marco; Shibli, Jamil A; Vantaggiato, Giovanni; Piattelli, Adriano; Perrotti, Vittoria

    2013-01-01

    The aim of this study was to histologically and histomorphometrically analyze the peri-implant tissue reactions and the bone-titanium interface in loaded Ankylos implants retrieved after loading periods of longer than 1 year. The archives of the Implant Retrieval Center of the Dental School of the University of Chieti- Pescara were searched for Ankylos implants retrieved from humans after a loading period of longer than 1 year. A total of four implants were found: one had been retrieved after 3 years (Friadent plus surface), two after 3.5 years (Friadent plus surface), and one after 10 years (Deep Profile surface). All implants had been loaded; two had been loaded immediately. One implant was retrieved after fracture, one was retrieved after fracture of the superstructure, and the other two were retrieved because of bone resorption with or without infection. Compact bone with few small marrow spaces was present around the three implants retrieved after 3 and 3.5 years; trabecular bone was present around the implant retrieved after 10 years. The bone-implant contact of the three best threads was 35% for the implant retrieved after 10 years, 99% for the implant retrieved after 3 years, and 100% for the implants retrieved after 3.5 years. No untoward effects were present at the interface, and a high bone-implant contact was present around the implants with the microstructured surface. The data show that these implants had the potential to maintain osseointegration under long-term function with continuous and ongoing bone remodeling.

  11. Relationship between Fibroblast Growth Factor 23 and Biochemical and Bone Histomorphometric Alterations in a Chronic Kidney Disease Rat Model Undergoing Parathyroidectomy

    PubMed Central

    Liao, Hung-Wei; Hung, Peir-Haur; Hsiao, Chih-Yen; Liou, Hung-Hsiang; Lin, Hsin-Shih; Huang, Tsang-Hai; Jou, I-Ming; Tsai, Kuen-Jer

    2015-01-01

    Background Phosphate burden in chronic kidney disease (CKD) leads to elevated serum fibroblast factor-23 (FGF-23) levels, secondary hyperparathyroidism and chronic kidney disease-mineral bone disorder (CKD-MBD). However dissociated hyperphosphatemia and low serum FGF-23 concentrations have been observed in experimentally parathyoridectomized rats. The relationships between serum mineral, hormone, and bone metabolism may be altered in the presence of CKD. The aim of our study was to investigate whether a consistent relationship existed between serum FGF-23 levels, specific serum biochemical markers, and histomorphometric parameters of bone metabolism in a parathyroidectomized CKD animal model. Results Sprague Dawley rats were divided into 3 groups: parathyroidectomy (PTX) and CKD (PTX+CKD, 9 rats), CKD without PTX (CKD, 9 rats), and neither PTX nor CKD (sham-operated control, 8 rats); CKD was induced by partial nephrectomy. At 8 weeks after partial nephrectomy, serum biomarkers were measured. Bone histomorphometries of the distal femoral metaphyseal bone were analyzed. The mean serum FGF-23 levels and mean bone formation rate were the highest in the CKD group and the lowest in the PTX+CKD group. Bone volume parameters increased significantly in the PTX+CKD group. Pearson’s correlation revealed that serum FGF-23 levels associated with those of intact parathyroid hormone, phosphate, collagen type I C-telopeptide, and calcium. Univariate linear regression showed that serum FGF-23 values correlated with bone formation rate, bone volume, and osteoid parameters. Stepwise multivariate regression analysis revealed that circulating FGF-23 values were independently associated with bone volume and thickness (β = -0.737; p < 0.001 and β = -0.526; p = 0.006, respectively). Serum parathyroid hormone levels independently correlated with bone formation rate (β = 0.714; p < 0.001) while collagen type I C-telopeptide levels correlated with osteoid parameter. Conclusion Serum FGF

  12. Comparing classification methods for longitudinal fMRI studies.

    PubMed

    Schmah, Tanya; Yourganov, Grigori; Zemel, Richard S; Hinton, Geoffrey E; Small, Steven L; Strother, Stephen C

    2010-11-01

    We compare 10 methods of classifying fMRI volumes by applying them to data from a longitudinal study of stroke recovery: adaptive Fisher's linear and quadratic discriminant; gaussian naive Bayes; support vector machines with linear, quadratic, and radial basis function (RBF) kernels; logistic regression; two novel methods based on pairs of restricted Boltzmann machines (RBM); and K-nearest neighbors. All methods were tested on three binary classification tasks, and their out-of-sample classification accuracies are compared. The relative performance of the methods varies considerably across subjects and classification tasks. The best overall performers were adaptive quadratic discriminant, support vector machines with RBF kernels, and generatively trained pairs of RBMs.

  13. Comparative study of lung functions in swimmers and runners.

    PubMed

    Sable, Meenakshi; Vaidya, S M; Sable, S S

    2012-01-01

    In the present study pulmonary function tests of two different groups of athletes, swimmers and runners were studied and compared. Thirty swimmers who used to swim a distance of two to three kilometers per day regularly were compared with age, sex, height, and weight matched thirty middle distance runners. Runners and swimmers selected for this study were undergoing training since last three years. Tidal Volume (TV), forced Vital Capacity (FVC). Forced expiratory volume in one second (FEV1) and maximum voluntary ventilation (MVV) were higher in swimmers than runners. Swimming exercise affects lung volume measurements as respiratory muscles including diaphragm of swimmers are required to develop greater pressure as a consequence of immersion in water during respiratory cycle, thus may lead to functional improvement in these muscles and also alterations in elasticity of lung and chest wall or of ventilatory muscles, leading to an improvement in forced vital capacity and other lung functions of swimmers than runners.

  14. Comparative chemical study of MTA and Portland cements.

    PubMed

    Oliveira, Marília Gerhardt de; Xavier, Cristina Braga; Demarco, Flávio Fernando; Pinheiro, Antônio Luis Barbosa; Costa, Aline Tempel; Pozza, Daniel Humberto

    2007-01-01

    Portland cement has been analyzed and compared to mineral trioxide aggregate (MTA) because of their chemical similarity. The possibility of using this material as a less expensive alternative to MTA in dental practice should be considered. In view of this, the present study compared the components of a Portland cement (Votoran) to two commercial brands of MTA (Pro-Root and MTA-Angelus). Twelve specimens of each material were fabricated and examined by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) to obtain their percentage of chemical elements. The means of the chemical elements found in each material was compared by descriptive statistics. Bismuth was present only in MTA cements to provide radiopacity. In conclusion, the tested cements have similar components, which supports, as far as composition is concerned, the possible clinical use of Portland as an option to MTA.

  15. Analytical lessons learned from selected therapeutic protein drug comparability studies.

    PubMed

    Federici, Marcia; Lubiniecki, Anthony; Manikwar, Prakash; Volkin, David B

    2013-05-01

    The successful implementation of process and product changes for a therapeutic protein drug, both during clinical development and after commercialization, requires a detailed evaluation of their impact on the protein's structure and biological functionality. This analysis is called a comparability exercise and includes a data driven assessment of biochemical equivalence and biological characterization using a cadre of analytical methodologies. This review focuses on describing analytical results and lessons learned from selected published therapeutic protein comparability case studies both for bulk drug substance and final drug product. An overview of the currently available analytical methodologies typically used is presented as well as a discussion of new emerging analytical techniques. The potential utility of several novel analytical approaches to comparability studies is discussed including distribution and stability of protein drugs in vivo, and enhanced evaluation of higher-order protein structure in actual formulations using hydrogen/deuterium exchange mass spectrometry, two-dimensional nuclear magnetic resonance fingerprinting or empirical phase diagrams. In addition, new methods for detecting and characterizing protein aggregates and particles are presented as these degradants are of current industry-wide concern. The critical role that analytical methodologies play in elucidating the structure-function relationships for therapeutic protein products during the overall assessment of comparability is discussed.

  16. Comparative study of infrared wavefront sensing solutions for adaptive optics

    NASA Astrophysics Data System (ADS)

    Plantet, C.; Fusco, T.; Guerineau, N.; Derelle, S.; Robert, C.

    2016-07-01

    The development of new low-noise infrared detectors, such as RAPID (CEA LETI/Sofradir) or SAPHIRA (Selex), has given the possibility to consider infrared wavefront sensing at low ux. We propose here a comparative study of near infrared (J and H bands) wavefront sensing concepts for mid and high orders estimation on a 8m- class telescope, relying on three existing wavefront sensors: the Shack-Hartmann sensor, the pyramid sensor and the quadri-wave lateral shearing interferometer. We consider several conceptual designs using the RAPID camera, making a trade-off between background flux, optical thickness and compatibility with a compact cryostat integration. We then study their sensitivity to noise in order to compare them in different practical scenarios. The pyramid provides the best performance, with a gain up to 0.5 magnitude, and has an advantageous setup.

  17. Comparative study of turbulence models in predicting hypersonic inlet flows

    NASA Technical Reports Server (NTRS)

    Kapoor, Kamlesh; Anderson, Bernhard H.; Shaw, Robert J.

    1992-01-01

    A numerical study was conducted to analyze the performance of different turbulence models when applied to the hypersonic NASA P8 inlet. Computational results from the PARC2D code, which solves the full two-dimensional Reynolds-averaged Navier-Stokes equation, were compared with experimental data. The zero-equation models considered for the study were the Baldwin-Lomax model, the Thomas model, and a combination of the Baldwin-Lomax and Thomas models; the two-equation models considered were the Chien model, the Speziale model (both low Reynolds number), and the Launder and Spalding model (high Reynolds number). The Thomas model performed best among the zero-equation models, and predicted good pressure distributions. The Chien and Speziale models compared wery well with the experimental data, and performed better than the Thomas model near the walls.

  18. Comparative study of turbulence models in predicting hypersonic inlet flows

    NASA Technical Reports Server (NTRS)

    Kapoor, Kamlesh; Anderson, Bernhard H.; Shaw, Robert J.

    1992-01-01

    A numerical study was conducted to analyze the performance of different turbulence models when applied to the hypersonic NASA P8 inlet. Computational results from the PARC2D code, which solves the full two-dimensional Reynolds-averaged Navier-Stokes equation, were compared with experimental data. The zero-equation models considered for the study were the Baldwin-Lomax model, the Thomas model, and a combination of the Baldwin-Lomax and Thomas models; the two-equation models considered were the Chien model, the Speziale model (both low Reynolds number), and the Launder and Spalding model (high Reynolds number). The Thomas model performed best among the zero-equation models, and predicted good pressure distributions. The Chien and Speziale models compared very well with the experimental data, and performed better than the Thomas model near the walls.

  19. Positioning for Endovenous Laser Ablation: Comparative Study with Thigh Stripping

    PubMed Central

    Masaki, Hisao; Yunoki, Yasuhiro; Watanabe, Yoshiko; Furukawa, Hiroshi; Yamasawa, Takahiko; Takiuchi, Hiroki; Honda, Takeshi; Kuwada, Noriaki; Kojima, Kenji; Tanemoto, Kazuo

    2016-01-01

    We performed a comparative study of surgical outcomes and venous functions between endovenous laser ablation with a 980-nm diode laser (EV group) and thigh stripping (ST group). There were no severe complications and initial success rates were 100% in both groups. In the EV group, preoperative symptoms improved in 94.3% of cases, the venous occlusion rate was 98%, and endovenous heat induced thrombosis had occurred in 11.9% (Class 3: 0.7%) at 12 months after the operation. Although comparative study of postoperative venous function by air plethysmography showed significant improvement in both groups, there was less recovery of postoperative venous function in the EV than in the ST group. (This article is a translation of J Jpn Coll Angiol 2015; 55: 13–20.) PMID:27738455

  20. [Fatal child abuse in Japan and Germany. Comparative retrospective study].

    PubMed

    Ohtsuji, M; Ohshima, T; Kondo, T; Godoy, M R; Oehmichen, M

    1998-01-01

    In this study a record for comparative international epidemiological studies on autopsy cases of child abuse is introduced. The form was proved in a retrospective comparative survey of cases of fatal child abuse at the Department of Legal Medicine in Kanazawa (Japan) and Institute of Legal Medicine of Lübeck (Germany). A total of 33 cases were included. The following data were evaluated: age and gender of victims and assailants, relationship between victims and assailants, causes and methods of abuse, chief autopsy findings, and causes of death. The results were leading into two directions between Kanazawa and Lübeck: (1) In the years of 1981-1996 in Kanazawa 23 cases of fatal child abuse were autopsied while during the same period in Lübeck only 10 cases were registered. (2) While sexual abuse was not registered in Kanazawa, it was recorded twice in Lübeck.

  1. What is AIDS in Guadeloupe? A descriptive and comparative study.

    PubMed

    Elenga, Narcisse; Georger-Sow, Marie-Thérèse; Messiaen, Thierry; Lamaury, Isabelle; Favre, Isabelle; Nacher, Mathieu; Beaucaire, Gilles

    2014-03-01

    Since the pathogen ecology differs between Caribbean regions, specific differences in the most frequent clinical presentations of acquired immunodeficiency syndrome (AIDS) may be expected. We therefore conducted the present retrospective cohort study in order to describe the main AIDS-defining events in Guadeloupe and to compare them with those observed in Metropolitan France and in French Guiana. We discuss the local pathogen ecology, the diagnostic limitations of hospitals in overseas territories and the drivers of the epidemic.

  2. Magnetic field effect on indole exciplexes: a comparative study

    NASA Astrophysics Data System (ADS)

    Sengupta, Tamal; Basu, Samita

    2004-04-01

    A comparative magnetic field effect (MFE) study was done on indole exciplexes with various acceptors, anthracene, pyrene, all-s- trans-1,4-diphenylbuta-1,3-diene and 9-cyanophenanthrene. A surprisingly low magnetic field effect was detected for the 9-cyanophenanthrene exciplexes and was correlated with exciplex geometry. The wavelength dependence of magnetic field effect confirms the presence of single charge-transfer complex for all the exciplexes with 1,2-dimethylindole.

  3. Comparative Statistical Study of Some SAP UI Technologies

    NASA Astrophysics Data System (ADS)

    Berdie, Adela; Osaci, Mihaela; Dan Lemle, Ludovic

    2011-09-01

    The goal of this paper is to present a comparative study on some web UI (User Interface) technologies that involve the creation of web applications on the platform SAP Net Weaver AS 7.01 of the integrated SAP (System Application Products) system. The attention will be directed mainly to the ABAP (Advanced Business Application Programing) development environment and to the Web Dynpro (WD) technologies, Floor Plan Manager (FPM) and Web Client UI. Through this study, we make an assesment regarding the decision of choosing a technology for the realisation of a project which consists of a web application.

  4. Image based 3D city modeling : Comparative study

    NASA Astrophysics Data System (ADS)

    Singh, S. P.; Jain, K.; Mandla, V. R.

    2014-06-01

    3D city model is a digital representation of the Earth's surface and it's related objects such as building, tree, vegetation, and some manmade feature belonging to urban area. The demand of 3D city modeling is increasing rapidly for various engineering and non-engineering applications. Generally four main image based approaches were used for virtual 3D city models generation. In first approach, researchers were used Sketch based modeling, second method is Procedural grammar based modeling, third approach is Close range photogrammetry based modeling and fourth approach is mainly based on Computer Vision techniques. SketchUp, CityEngine, Photomodeler and Agisoft Photoscan are the main softwares to represent these approaches respectively. These softwares have different approaches & methods suitable for image based 3D city modeling. Literature study shows that till date, there is no complete such type of comparative study available to create complete 3D city model by using images. This paper gives a comparative assessment of these four image based 3D modeling approaches. This comparative study is mainly based on data acquisition methods, data processing techniques and output 3D model products. For this research work, study area is the campus of civil engineering department, Indian Institute of Technology, Roorkee (India). This 3D campus acts as a prototype for city. This study also explains various governing parameters, factors and work experiences. This research work also gives a brief introduction, strengths and weakness of these four image based techniques. Some personal comment is also given as what can do or what can't do from these softwares. At the last, this study shows; it concluded that, each and every software has some advantages and limitations. Choice of software depends on user requirements of 3D project. For normal visualization project, SketchUp software is a good option. For 3D documentation record, Photomodeler gives good result. For Large city

  5. Comparative inhalation studies with American and Estonian oil shale

    SciTech Connect

    Holland, L.M.; Vigil, E.A.; Gonzales, M.; Tillery, M.I.

    1981-01-01

    This paper presents interim findings on studies comparing the effects of long-term inhalation of quartz, Estonian kukersite, or American Green River shales in rats. No tumors have been observed in the exposed animals. In the studies with Green River shales, the rate of death increased as the animals approached 2 years of exposure. Varying degrees of lung fibrosis has been noted in these animals also. Animals in the kukersite group exhibited only mild changes with some alveolar thickening, and increased macrophages and collagen. Quartz exposed animals suffered severe fibrosis after several months exposure and died after 12 to 15 months.

  6. A comparative study of fluoride release from two different sealants

    PubMed Central

    Ananda, Shimoga-Raju

    2014-01-01

    Objectives: The introduction of fluoride releasing sealants and glass ionomer cements as fissure sealants adds another dimension to prevention of pit and fissure caries. The ability of resin sealants and glass ionomer cements to release fluoride on a long term basis to the sealed enamel and the adjacent unsealed pit and fissure and cuspal incline enamel may allow for further reduction in pit and fissure caries experience for children. Hence, the study was conducted to compare the amount of fluoride release in the plaque after placing fluoride releasing pit and fissure sealants and glass ionomer fissure sealants used in Atraumatic Restorative Treatment (ART) approach. To compare the fluoride release of both the materials at the different time intervals. Material and Methods: A total of 60 school going children were included in this study. Before application of the sealants, baseline plaque fluoride levels were estimated from all the study subjects. After application of sealants again the same was estimated at an interval of 24 hour, 9 days, 2 weeks and 4 weeks. Results: The peak plaque fluoride levels were achieved at 24 hours after application of fissure sealants in all the groups. Conclusions: Within the limitation of the study, the present study indicated that fluoride releasing fissure sealants may act as a source of fluoride in plaque which will help in preventing pit and fissure and smooth surface caries in the tooth sealed with fissure sealants. Key words:Plaque fluoride, pit and fissures sealants, dental caries. PMID:25674315

  7. Comparative photodynamic therapy study using two phthalocyanine derivatives

    PubMed Central

    YSLAS, EDITH INÉS; MILLA, LAURA NATALIA; ROMANINI, SILVIA; DURANTINI, EDGARDO NÉSTOR; BERTUZZI, MABEL; RIVAROLA, VIVIANA ALICIA

    2010-01-01

    In the present study, a comparative photodynamic therapy (PDT) study was performed using the phthalocyanine derivatives, ZnPc(OCH3)4 and ZnPc(CF3)4, in a mouse tumor model, under identical experimental procedures. We studied the ablation of tumors induced by PDT. The end-point was to compare the photodynamic efficacy of ZnPc(OCH3)4 and ZnPc(CF3)4. ZnPc(OCH3)4 and ZnPc(CF3)4 were administered intraperitoneally at a dose of 0.2 mg/kg body weight. The injections of drugs were carried out in Balb/c mice bearing subcutaneously inoculated LM2 mouse mammary adenocarcinoma. Histological examination and serum biochemical parameters were used to evaluate hepatic and renal toxicity and function. Phototherapeutic studies were achieved employing a light intensity of 210 J/cm2. After PDT, tumoral regression analyses were carried out, and the degree of tumor cell death was measured utilizing the vital stain Evan’s blue. In this pilot study, we revealed that the cytotoxic effect of ZnPc(OCH3)4 after PDT led to a higher success rate compared to ZnPc(CF3)4-PDT when both were intraperitoneally injectioned. Both phthalocynanine derivatives were able to induce ablation in the tumors. In summary, these results demonstrate the feasibility of ZnPc(OCH3)4- or ZnPc(CF3)4-PDT and its potential as a treatment for small tumors. PMID:22993594

  8. A Histomorphometric Analysis of Radiation Damage in an Isogenic Murine Model of Distraction Osteogenesis

    PubMed Central

    Zheutlin, Alexander R.; Deshpande, Sagar S.; Nelson, Noah S.; Polyatskaya, Yekaterina; Rodriguez, Jose J.; Donneys, Alexis; Buchman, Steven R.

    2015-01-01

    Purpose The devastation radiation therapy (XRT) causes to endogenous tissue in head and neck cancer (HNC) patients can be a prohibitive obstacle in reconstruction of the mandible, demanding a better understanding of XRT-induced damage and options for reconstruction. Our study investigates the cellular damage caused by radiation in an isogenic murine model of mandibular distraction osteogenesis (DO). We posit that radiation will result in reduced osteocytes, with elevated empty lacunae and immature osteoid. Methods Twenty Lewis rats were randomly assigned to two groups: DO (n=10) and XRT/DO (n=10). Both groups underwent an osteotomy and mandibular DO across a 5.1 mm gap. XRT was administered to the XRT/DO group at a fractionated, human equivalent dose of 35 Gy prior to surgery. Animals were sacrificed on postoperative day 40 and mandibles were harvested and sectioned for histological analysis. Results Bone that underwent radiation revealed a significantly decreased osteocyte count and complementary increase in empty lacunae when compared to non-XRT bone (p=0.019, p=0.000). Additionally, XRT bone demonstrated increased immature osteoid and decreased mature woven bone when compared to non-radiated bone (p=0.001 and p=0.003, respectively). Furthermore, analysis of the ratio of immature osteoid to woven bone volume exhibited a significant increase in the XRT bone, further revealing the devastating damage brought by XRT (p=0.001). Conclusion These results clearly demonstrate the cellular diminution that occurs as a result of radiation. This foundational study provides the groundwork upon which to investigate cellular therapies in an immunoprivileged model of mandibular DO. PMID:26341682

  9. Comparative study of gabapentin and isoflavone in menopausal vasomotor symptoms

    PubMed Central

    Singhal, Savita Rani; Shullai, Wansalan Kuru

    2016-01-01

    Objective: This study was planned to compare the effects of gabapentin and isoflavones in menopausal vasomotor symptoms. Materials and Methods: This prospective comparative study was conducted on 100 patients with complaints of hot flashes, divided into two groups of 50 each. Group I received 900 mg of gabapentin and Group II received 60 mg of isoflavones daily for 3 months. The patients were interviewed to calculate hot flash, global and depression scores and were rescored after 2, 4, 8, and 12 weeks. The primary outcome measure was a change in the hot flash score from baseline. The secondary outcome was an improvement in sleep, depression, and lipid profile. Data were analyzed using Chi-square test and Student's t-test. Results: Both groups showed significant improvement in hot flash score at the end of 12 weeks (82% Group I, 74% Group II; P = 0.076). Statistically significant difference was seen at 12 weeks in sleep quality in favor of gabapentin (P = 0.011) and in depression in favor of isoflavones (0.026). Isoflavone had significant improvement in cholesterol, high-density lipoprotein, low-density lipoprotein, and triglycerides profiles after 12 weeks (P < 0.001, 0.009, 0.024 and <0.001, respectively) as compared to gabapentin. Conclusion: Isoflavone and gabapentin are equally effective in the treatment of hot flashes; however, isoflavones have better response in patients who have associated with complaints of depression and gabapentin is better who have associated sleep disturbance. PMID:27721641

  10. Cardamine hirsuta: a versatile genetic system for comparative studies.

    PubMed

    Hay, Angela S; Pieper, Bjorn; Cooke, Elizabeth; Mandáková, Terezie; Cartolano, Maria; Tattersall, Alexander D; Ioio, Raffaele D; McGowan, Simon J; Barkoulas, Michalis; Galinha, Carla; Rast, Madlen I; Hofhuis, Hugo; Then, Christiane; Plieske, Jörg; Ganal, Martin; Mott, Richard; Martinez-Garcia, Jaime F; Carine, Mark A; Scotland, Robert W; Gan, Xiangchao; Filatov, Dmitry A; Lysak, Martin A; Tsiantis, Miltos

    2014-04-01

    A major goal in biology is to identify the genetic basis for phenotypic diversity. This goal underpins research in areas as diverse as evolutionary biology, plant breeding and human genetics. A limitation for this research is no longer the availability of sequence information but the development of functional genetic tools to understand the link between changes in sequence and phenotype. Here we describe Cardamine hirsuta, a close relative of the reference plant Arabidopsis thaliana, as an experimental system in which genetic and transgenic approaches can be deployed effectively for comparative studies. We present high-resolution genetic and cytogenetic maps for C. hirsuta and show that the genome structure of C. hirsuta closely resembles the eight chromosomes of the ancestral crucifer karyotype and provides a good reference point for comparative genome studies across the Brassicaceae. We compared morphological and physiological traits between C. hirsuta and A. thaliana and analysed natural variation in stamen number in which lateral stamen loss is a species characteristic of C. hirsuta. We constructed a set of recombinant inbred lines and detected eight quantitative trait loci that can explain stamen number variation in this population. We found clear phylogeographic structure to the genetic variation in C. hirsuta, thus providing a context within which to address questions about evolutionary changes that link genotype with phenotype and the environment.

  11. Comparing protein VEGF inhibitors: In vitro biological studies

    SciTech Connect

    Yu, Lanlan; Liang, Xiao Huan; Ferrara, Napoleone

    2011-05-06

    Highlights: {yields} VEGF is a mediator of angiogenesis. {yields} VEGF inhibitors have clinical applications in cancer and eye disorders. {yields} Five protein VEGF inhibitors were compared for their ability to inhibit. {yields} VEGF-induced activities in cultured endothelial cells. -- Abstract: VEGF inhibitors are widely used as a therapy for tumors and intravascular neovascular disorders, but limited and conflicting data regarding their relative biological potencies are available. The purpose of the study is to compare different protein VEGF inhibitors for their ability to inhibit VEGF-stimulated activities. We tested ranibizumab, the full-length variant of ranibizumab (Mab Y0317), bevacizumab, the VEGF-TrapR1R2 and Flt(1-3)-IgG in bioassays measuring VEGF-stimulated proliferation of bovine retinal microvascular endothelial cells or chemotaxis of human umbilical vein endothelial cells (HUVEC). The inhibitors were also compared for their ability to inhibit MAP kinase activation in HUVECs following VEGF addition. Ranibizumab, VEGF-TrapR1R2 and Flt(1-3)-IgG had very similar potencies in the bioassays tested. Bevacizumab was over 10-fold less potent than these molecules. Mab Y0317 was over 30-fold more potent than bevacizumab. The findings reported in this manuscript describe important intrinsic characteristics of several VEGF inhibitors that may be useful to design and interpret preclinical or clinical studies.

  12. A comparative study of bifidobacteria in human babies and adults

    PubMed Central

    KHONSARI, Shadi; SUGANTHY, Mayuran; BURCZYNSKA, Beata; DANG, Vu; CHOUDHURY, Manika; PACHENARI, Azra

    2015-01-01

    The composition and diversity of the gut microbiota are known to be different between babies and adults. The aim of this project was to compare the level of bifidobacteria between babies and adults and to investigate the influence of lifestyle factors on the level of this bacterium in the gut. During this study, the levels of bifidobacteria in 10 human babies below 2 years of age were compared with that of 10 human adults above 40 years. The level of bifidobacteria proved to be significantly higher in babies in comparison with adults. This investigation concluded that a combination of several factors, such as age, diet, and BMI, has an important effect on the level of bifidobacteria in adults, while in babies, a combination of diet and age may influence the level of intestinal bifidobacteria. PMID:27200263

  13. Comparative study of convective heat transfer characteristics of nanofluids

    NASA Astrophysics Data System (ADS)

    Muryam, Hina; Ramzan, Naveed; Umer, Asim; Awan, Gul Hameed; Hassan, Ali

    2017-02-01

    The present research is about to draw a comparison between heat transfer characteristics of gold/deionized water (DIW) and silver/DIW based nanofluid under same heat flux for laminar flow. Experiments are performed on both nanofluid by using different concentrations (0.015, 0.045, 0.0667%) of nano-particles (NPs) in DIW as a base fluid. The experimental study concludes that an appreciable intensification in heat transfer coefficient (HTC) of both nanofluid has been attained as compare to base fluid. However, gold/DIW based nanofluid exhibit better convective heat transfer intensification compared with silver/DIW based nanofluid but Shah correlation cannot predict as much augmentation as in experimental work for both nanofluid. It is also noticed that the anomalous enhancement in Nusselt number and HTC is not only due to the accession in thermal properties but also by the formation of thinner thermal boundary layer at the entrance of the tube due to NPs.

  14. A Comparative Study on Emerging Electric Vehicle Technology Assessments

    SciTech Connect

    Ford, Jonathan; Khowailed, Gannate; Blackburn, Julia; Sikes, Karen

    2011-03-01

    Numerous organizations have published reports in recent years that investigate the ever changing world of electric vehicle (EV) technologies and their potential effects on society. Specifically, projections have been made on greenhouse gas (GHG) emissions associated with these vehicles and how they compare to conventional vehicles or hybrid electric vehicles (HEVs). Similar projections have been made on the volumes of oil that these vehicles can displace by consuming large amounts of grid electricity instead of petroleum-based fuels. Finally, the projected rate that these new vehicle fleets will enter the market varies significantly among organizations. New ideas, technologies, and possibilities are introduced often, and projected values are likely to be refined as industry announcements continue to be made. As a result, over time, a multitude of projections for GHG emissions, oil displacement, and market penetration associated with various EV technologies has resulted in a wide range of possible future outcomes. This leaves the reader with two key questions: (1) Why does such a collective range in projected values exist in these reports? (2) What assumptions have the greatest impact on the outcomes presented in these reports? Since it is impractical for an average reader to review and interpret all the various vehicle technology reports published to date, Sentech Inc. and the Oak Ridge National Laboratory have conducted a comparative study to make these interpretations. The primary objective of this comparative study is to present a snapshot of all major projections made on GHG emissions, oil displacement, or market penetration rates of EV technologies. From the extensive data found in relevant publications, the key assumptions that drive each report's analysis are identified and 'apples-to-apples' comparisons between all major report conclusions are attempted. The general approach that was taken in this comparative study is comprised of six primary steps: (1

  15. Discourse Formation in Comparative Education. 4th, Revised Edition. Comparative Studies Series. Volume 10

    ERIC Educational Resources Information Center

    Schriewer, Jurgen, Ed.

    2012-01-01

    New theories and theory-based methodological approaches have found their way into Comparative Education--just as into Comparative Social Science more generally--in increasing number in the recent past. The essays of this volume express and critically discuss quite a range of these positions such as, inter alia, the theory of self-organizing social…

  16. Effect of laser phototherapy on human alveolar bone repair: micro tomographic and histomorphometrical analysis

    NASA Astrophysics Data System (ADS)

    Romão, Marcia M. A.; Marques, Márcia M.; Cortes, Arthur R. G.; Horliana, Anna C. R. T.; Moreira, Maria S.; Lascala, Cesar A.

    2015-06-01

    The immediate dental implant placement in the molars region is critical, because of the high amount of bone loss and the discrepancy between the alveolar crest thickness and the dental implant platform. Laser phototherapy (LPT) improves bone repair thus could accelerate the implant placement. Twenty patients were selected for the study. Ten patients were submitted to LPT with GaAlAs diode laser (808nm) during molar extraction, immediately after, 24h, 48h, 72h, 96h and 7 days. The irradiations were applied in contact and punctual mode (100mW, 0.04cm2, 0.75J/cm2, 30s per point, 3J per point). The control group (n=10) received the same treatment; however with the power of the laser off. Forty days later samples of the tissue formed inside the sockets were obtained for further microtomography (microCTs) and histomorphometry analyses. Data were compared by the Student t test, whereas those from the different microCT parameters were compared by the Pearson correlation test (p<0.05). The relative bone volume, as well as area was significantly higher (p<0.001) in the lased than the control group. In the control group there were negative correlations between number and thickness, and between number and separation of trabecula (p<0.01). Between thickness and separation of trabecula the correlation was positive (p<0.01). The laser group showed significant negative correlation between the number and the thickness of trabecula (p<0.01). LPT accelerated bone repair. By the Pearson correlation test it was possible to infer that the lased group presented a more homogeneous trabecular configuration, which would allow earlier dental implant placement.

  17. Comparative Study of Edge Detectors in case of Echocardiographic Images

    NASA Astrophysics Data System (ADS)

    Saini, Kalpana; Dewal, M. L.; Rohit, Manoj Kumar

    2010-11-01

    In this paper we compare different edge detectors based on peak signal to noise ratio on Echocardiographic images. Edge detection is a critical element in image processing, since edges contain a major function of image information. The function of edge detection is to identify the boundaries of homogeneous regions in an image based on properties such as intensity and texture.We have taken Perwitt edge detector, Robarts edge detector, LoG edge detector, Canny edge detector, and Sobel edge detector for this comparison and study.

  18. Comparative study of minutiae selection algorithms for ISO fingerprint templates

    NASA Astrophysics Data System (ADS)

    Vibert, B.; Charrier, C.; Le Bars, J.-M.; Rosenberger, C.

    2015-03-01

    We address the selection of fingerprint minutiae given a fingerprint ISO template. Minutiae selection plays a very important role when a secure element (i.e. a smart-card) is used. Because of the limited capability of computation and memory, the number of minutiae of a stored reference in the secure element is limited. We propose in this paper a comparative study of 6 minutiae selection methods including 2 methods from the literature and 1 like reference (No Selection). Experimental results on 3 fingerprint databases from the Fingerprint Verification Competition show their relative efficiency in terms of performance and computation time.

  19. Comparative studies on the efficacy of brotizolam and nitrazepam

    PubMed Central

    Lohmann, H.; Von Delbrück, Orla; Findeisen, P.

    1983-01-01

    1 Efficacy and tolerability of brotizolam (0.25 and 0.5 mg) were compared over a 6-day period with nitrazepam (5.0 mg) in middle-aged patients (less than 65 years) with sleep disturbances requiring medication. The study was double-blind and randomised with a cross-over design. 2 Each preparation reduced sleep onset latency and frequency of awakenings, and improved quality and duration of sleep as well as subjective condition on awakening. Brotizolam 0.25 mg was found to be equally effective as 0.5 mg, and so the lower dose is recommended for the middle aged. PMID:6362699

  20. Osseointegration and biocompatibility of different metal implants - a comparative experimental investigation in sheep

    PubMed Central

    2012-01-01

    Background In the present study, 4 different metallic implant materials, either partly coated or polished, were tested for their osseointegration and biocompatibility in a pelvic implantation model in sheep. Methods Materials to be evaluated were: Cobalt-Chrome (CC), Cobalt-Chrome/Titanium coating (CCTC), Cobalt-Chrome/Zirconium/Titanium coating (CCZTC), Pure Titanium Standard (PTST), Steel, TAN Standard (TANST) and TAN new finish (TANNEW). Surgery was performed on 7 sheep, with 18 implants per sheep, for a total of 63 implants. After 8 weeks, the specimens were harvested and evaluated macroscopically, radiologically, biomechanically (removal torque), histomorphometrically and histologically. Results Cobalt-Chrome screws showed significantly (p = 0.031) lower removal torque values than pure titanium screws and also a tendency towards lower values compared to the other materials, except for steel. Steel screws showed no significant differences, in comparison to cobalt-chrome and TANST, however also a trend towards lower torque values than the remaining materials. The results of the fluorescence sections agreed with those of the biomechanical test. Histomorphometrically, there were no significant differences of bone area between the groups. The BIC (bone-to-implant-contact), used for the assessment of the osseointegration, was significantly lower for cobalt-chrome, compared to steel (p = 0.001). Steel again showed a lower ratio (p = 0.0001) compared to the other materials. Conclusion This study demonstrated that cobalt-chrome and steel show less osseointegration than the other metals and metal-alloys. However, osseointegration of cobalt-chrome was improved by zirconium and/or titanium based coatings (CCTC, TANST, TAN, TANNEW) being similar as pure titanium in their osseointegrative behavior. PMID:22400715

  1. Radioactivity of natural and artificial building materials - a comparative study.

    PubMed

    Szabó, Zs; Völgyesi, P; Nagy, H É; Szabó, Cs; Kis, Z; Csorba, O

    2013-04-01

    Building materials and their additives contain radioactive isotopes, which can increase both external and internal radioactive exposures of humans. In this study Hungarian natural (adobe) and artificial (brick, concrete, coal slag, coal slag concrete and gas silicate) building materials were examined. We qualified 40 samples based on their radium equivalent, activity concentration, external hazard and internal hazard indices and the determined threshold values of these parameters. Absorbed dose rate and annual effective dose for inhabitants living in buildings made of these building materials were also evaluated. The calculations are based on (226)Ra, (232)Th and (40)K activity concentrations determined by gamma-ray spectrometry. Measured radionuclide concentrations and hence, calculated indices and doses of artificial building materials show a rather disparate distribution compared to adobes. The studied coal slag samples among the artificial building materials have elevated (226)Ra content. Natural, i.e. adobe and also brick samples contain higher amount of (40)K compared to other artificial building materials. Correlation coefficients among radionuclide concentrations are consistent with the values in the literature and connected to the natural geochemical behavior of U, Th and K elements. Seven samples (coal slag and coal slag concrete) exceed any of the threshold values of the calculated hazard indices, however only three of them are considered to be risky to use according to the fact that the building material was used in bulk amount or in restricted usage. It is shown, that using different indices can lead to different conclusions; hence we recommend considering more of the indices at the same time when building materials are studied. Additionally, adding two times their statistical uncertainties to their values before comparing to thresholds should be considered for providing a more conservative qualification. We have defined radon hazard portion to point

  2. Comparative study of Waste Isolation Pilot Plant (WIPP) transportation alternatives

    SciTech Connect

    Not Available

    1994-02-01

    WIPP transportation studies in the Final Supplement Environmental Impact Statement for WIPP are the baseline for this report. In an attempt to present the most current analysis, this study incorporates the most relevant data available. The following three transportation options are evaluated for the Disposal Phase, which is assumed to be 20 years: Truck shipments, consisting of a tractor and trailer, with three TRUPACT-IIs or one RH-72B; Regular commercial train shipments consisting of up to three railcars carrying up to 18 TRUPACT-IIs or up to six RH-72Bs; Dedicated train shipments consisting of a locomotive, an idle car, railcars carrying 18 TRUPACT-IIs or six RH-72Bs, another idle car, and a caboose or passenger car with an emergency response specialist. No other cargo is carried. This report includes: A consideration of occupational and public risks and exposures, and other environmental impacts; A consideration of emergency response capabilities; and An extimation of comparative costs.

  3. A comparative study on glyoxalase II from vertebrata.

    PubMed

    Principato, G B; Rosi, G; Talesa, V; Giovannini, E; Norton, S J

    1987-01-01

    S-2-hydroxyacylglutathione hydrolase (glyoxalase II) from the liver of animals belonging to the various vertebrate classes (Oryctolagus cuniculus, Gallus gallus, Python molurus, Rana esculenta, Esox lucius) have been purified from 100,000 g supernatants of liver homogenates, using acetone fractionation and affinity chromatography. Subsequent comparative studies were concerned with some molecular and kinetic properties. Isoelectric focusing gave evidence for a single form of liver glyoxalase II in O. cuniculus, P. molurus and E. lucius, while the enzyme from G. gallus and R. esculenta showed respectively two and three forms with different pI values. All studied enzymes are basic proteins. The relative molecular mass values range from 18,000 to 23,000. The various glyoxalases II do not display markedly different Kn or Ki values. Their stability behavior at different temperatures is also quite similar.

  4. Comparative studies of energy sources in gynecologic laparoscopy.

    PubMed

    Law, Kenneth S K; Lyons, Stephen D

    2013-01-01

    Energy sources incorporating "vessel sealing" capabilities are being increasingly used in gynecologic laparoscopic surgery although conventional monopolar and bipolar electrosurgery remain popular. The preference for one device over another is based on a combination of factors, including the surgeon's subjective experience, availability, and cost. Although comparative clinical studies and meta-analyses of laparoscopic energy sources have reported small but statistically significant differences in volumes of blood loss, the clinical significance of such small volumes is questionable. The overall usefulness of the various energy sources available will depend on a number of factors including vessel burst pressure and seal time, lateral thermal spread, and smoke production. Animal studies and laboratory-based trials are useful in providing a controlled environment to investigate such parameters. At present, there is insufficient evidence to support the use of one energy source over another.

  5. Comparative study of ring and random cavities for fiber lasers.

    PubMed

    Fernandez-Vallejo, Montserrat; Rota-Rodrigo, Sergio; Lopez-Amo, Manuel

    2014-06-01

    An experimental comparison of three fiber laser structures with the same Raman gain medium is presented in order to establish the main pros and cons of each basic scheme. The first fiber laser is based on a hybrid ring-random fiber laser, the second one is a pure ring fiber laser, and the last one is a random fiber laser. Several aspects have been taken into account in the study. First, from the optical point of view, the parameters of interest compared are output power, lasing threshold, slope efficiency, power fluctuations, and the longitudinal modes have been analyzed. Second, the possible utilization of fiber lasers in digital modulated optical communication systems is also studied.

  6. A Comparative Study on Automotive Brake Testing Standards

    NASA Astrophysics Data System (ADS)

    Kumbhar, Bhau Kashinath; Patil, Satyajit Ramchandra; Sawant, Suresh Maruti

    2016-06-01

    Performance testing of automotive brakes involves determination of stopping time, distance and deceleration level. Braking performance of an automobile is required to be ensured for various surfaces like dry, wet, concrete, bitumen etc. as well as for prolonged applications. Various brake testing standards are used worldwide to assure vehicle and pedestrian safety. This article presents methodologies used for automotive service brake testing for two wheelers. The main contribution of this work lies in comparative study of three main brake testing standards; viz. Indian Standards, Federal Motor Vehicle Safety Standards and European Economic Commission Standards. This study shall help the policy makers to choose the best criteria out of these three while formulating newer edition of testing standards.

  7. Comparative study of two commercially pure titanium casting methods

    PubMed Central

    RODRIGUES, Renata Cristina Silveira; FARIA, Adriana Claudia Lapria; ORSI, Iara Augusta; de MATTOS, Maria da Gloria Chiarello; MACEDO, Ana Paula; RIBEIRO, Ricardo Faria

    2010-01-01

    The interest in using titanium to fabricate removable partial denture (RPD) frameworks has increased, but there are few studies evaluating the effects of casting methods on clasp behavior. Objective This study compared the occurrence of porosities and the retentive force of commercially pure titanium (CP Ti) and cobalt-chromium (Co-Cr) removable partial denture circumferential clasps cast by induction/centrifugation and plasma/vacuum-pressure. Material and Methods 72 frameworks were cast from CP Ti (n=36) and Co-Cr alloy (n=36; control group). For each material, 18 frameworks were casted by electromagnetic induction and injected by centrifugation, whereas the other 18 were casted by plasma and injected by vacuum-pressure. For each casting method, three subgroups (n=6) were formed: 0.25 mm, 0.50 mm, and 0.75 mm undercuts. The specimens were radiographed and subjected to an insertion/removal test simulating 5 years of framework use. Data were analyzed by ANOVA and Tukey's to compare materials and cast methods (α=0.05). Results Three of 18 specimens of the induction/centrifugation group and 9 of 18 specimens of plasma/vacuum-pressure cast presented porosities, but only 1 and 7 specimens, respectively, were rejected for simulation test. For Co-Cr alloy, no defects were found. Comparing the casting methods, statistically significant differences (p<0.05) were observed only for the Co-Cr alloy with 0.25 mm and 0.50 mm undercuts. Significant differences were found for the 0.25 mm and 0.75 mm undercuts dependent on the material used. For the 0.50 mm undercut, significant differences were found when the materials were induction casted. Conclusion Although both casting methods produced satisfactory CP Ti RPD frameworks, the occurrence of porosities was greater in the plasma/vacuum-pressure than in the induction/centrifugation method, the latter resulting in higher clasp rigidity, generating higher retention force values. PMID:21085805

  8. A comparative study of ketanserin and metoprolol in essential hypertension.

    PubMed

    Kane, J A; Tooley, M; Sibbald, B; Gould, S E

    1986-04-01

    The efficacy and tolerability of ketanserin was compared with metoprolol in a double-blind parallel group study. After a 4-week placebo run-in on no treatment patients with a diastolic blood pressure (BP) of 95 mmHg or more received ketanserin 40 mg (n = 16) or metoprolol 100 mg (n = 17) twice daily. Blood pressure was measured in duplicate using a Hawksley random zero sphygmomanometer. Both blood pressure and heart rate were recorded after 5 min supine and 1 min standing. Patients visited after 2, 4, 8 and 12 weeks of treatment. Systolic, diastolic and mean arterial BPs, both supine and standing, were significantly reduced from week 2 by both treatments (P less than 0.05, Student's t-test). The mean (+/- s.e.m.) changes in supine BP at 3 months compared with baseline were -15.7 (3.6) mmHg systolic and -13.9 (2.7) mmHg diastolic in the ketanserin group and -26.6 (7.9) mmHg systolic and -15.2 (2.7) mmHg diastolic in the metoprolol group. There was a tendency for the fall in systolic BP to be greater in the metoprolol group, but this did not reach statistical significance except for the standing systolic BP at 1 month. Metoprolol caused a significant fall in heart rate compared with baseline values throughout the study, and the metoprolol group was significantly different from the ketanserin group at 2 months for the supine heart rate and at all time points for standing heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. A comparative study of Raman enhancement in capillaries

    NASA Astrophysics Data System (ADS)

    Eftekhari, Fatemeh; Irizar, Juan; Hulbert, Laila; Helmy, Amr S.

    2011-06-01

    This work reports on the comparative studies of Raman enhancement in liquid core waveguides (LCWs). The theoretical considerations that describe Raman enhancement in LCWs is adapted to analyze and compare the performance of hollow core photonic crystal fibers (HCPCFs) to conventional Teflon capillary tubes. The optical losses in both platforms are measured and used to predict their performance for different lengths. The results show that for an optimal waveguide length, two orders of magnitude enhancement in the Raman signal can be achieved for aqueous solutions using HCPCFs. This length, however, cannot be achieved using normal capillary effects. By integrating the interface of the fluidic pump and the HCPCF into a microfluidic chip, we are able to control fluid transport and fill longer lengths of HCPCFs regardless of the viscosity of the sample. The long-term stability and reproducibility of Raman spectra attained through this platform are demonstrated for naphthalenethiol, which is a well-studied organic compound. Using the HCPCF platform, the detection limit of normal Raman scattering in the range of micro-molars has been achieved. In addition to the higher signal-to-noise ratio of the Raman signal from the HCPCF-platform, more Raman modes of naphthalenethiol are revealed using this platform.

  10. Outpatient- and inpatient-based buckling surgery: a comparative study

    PubMed Central

    Lee, Jin Cheol; Kim, Yu Cheol

    2014-01-01

    Purpose To evaluate the clinical outcomes of ambulatory buckling surgery, comparing outpatient- with inpatient-based surgery. Methods The authors performed a retrospective study of 80 consecutive cases of rhegmato genous retinal detachment from January 2009 to December 2011 treated by scleral buckling surgery. Two groups of patients were defined according to inpatient (group 1) or outpatient (group 2) surgery, and a comparison of several parameters between these two groups was performed. Results Of the 80 subjects in this study, the average age of group 1 (50 patients) was 49.7 years, and that of group 2 (30 patients) was 47.5 years. There were no statistically significant differences in the average logarithm of the minimum angle of resolution-visual acuity, the condition of the lens, or the presence of retinal lattice degeneration prior to the surgery between the groups. There were no statistically significant differences in the patterns of tear or retinal detachment or in surgical procedure between the groups. Comparing the best-corrected visual acuity after 6 months with that prior to the surgery, the changes in group 1 and group 2 were 0.26 and 0.31, respectively. The functional success rates of group 1 and group 2 after 6 months were 90% and 93%, respectively, and the anatomical success rates of group 1 and group 2 after 6 months were 94% and 96%, respectively, but these were also statistically insignificant. Conclusion Hospitalization is not essential for buckling surgery in uncomplicated rhegmatogenous retinal detachment surgery. PMID:24812485

  11. Stress management and erectile dysfunction: a pilot comparative study.

    PubMed

    Kalaitzidou, I; Venetikou, M S; Konstadinidis, K; Artemiadis, A K; Chrousos, G; Darviri, C

    2014-08-01

    Erectile dysfunction (ED) is a complex disorder with various biopsychosocial implications leading the individual into a state of chronic stress that further worsens ED symptoms. The aim of this study is to investigate the effects of a 8-week stress management programme on erectile dysfunction (ED). A convenience sample of 31 newly diagnosed men with ED, aged between 20 and 55 years, was recruited during a period of 5 months to receive either tadalafil (12 patients) or tadalafil and the 8-week stress management programme. Both groups showed statistical significant improvement of both perceived stress and erectile function scores. Men practising stress management showed a statistical significant reduction in perceived stress score compared with men receiving tadalafil alone. No other statistical significant differences were noted between the two groups, although the stress management group showed a lower daily exposure to cortisol compared with the control group after 8 weeks. Finally, perceived stress and cortisol showed some interesting correlations with sexual function measurements. These findings provide important insight into the role of stress management, as part of the recommended biopsychosocial approach, in ED. Future studies should focus on randomised, controlled trials with larger samples and longer follow-up time.

  12. A comparative Study of Circulation Patterns at Active Lava Lakes

    NASA Astrophysics Data System (ADS)

    Lev, Einat; Oppenheimer, Clive; Spampinato, Letizia; Hernandez, Pedro; Unglert, Kathi

    2016-04-01

    Lava lakes present a rare opportunity to study magma dynamics in a large scaled-up "crucible" and provide a unique natural laboratory to ground-truth dynamic models of magma circulation. The persistence of lava lakes allows for long-term observations of flow dynamics and of lava properties, especially compared to surface lava flows. There are currently five persistent lava lakes in the world: Halemaumau in Kilauea (Hawaii, USA), Erta Ale (Ethiopia), Nyiragongo (Congo), Erebus (Antarctica), and Villarica (Chile). Marum and Benbow craters of Ambrym volcano (Vanuatu) and Masaya (Nicaragua) have often hosted lava lakes as well. We use visible-light and thermal infrared time-lapse and video footage collected at all above lakes (except Villarica, where the lake is difficult to observe), and compare the circulation patterns recorded. We calculate lake surface motion from the footage using the optical flow method (Lev et al., 2012) to produce 2D velocity fields. We mined both the surface temperature field and the surface velocity field for patterns using machine learning techniques such as "self-organizing maps (SOMs)" and "principle component analysis (PCA)". We use automatic detection technique to study the configuration of crustal plates at the lakes' surface. We find striking differences among the lakes, in flow direction, flow speed, frequency of changes in flow direction and speed, location and consistency of upwelling and downwelling, and crustal plate configuration. We relate the differences to lake size, shallow conduit geometry, lava viscosity, crystal and gas content, and crust integrity.

  13. A comparative phylogenetic study of genetics and folk music.

    PubMed

    Pamjav, Horolma; Juhász, Zoltán; Zalán, Andrea; Németh, Endre; Damdin, Bayarlkhagva

    2012-04-01

    Computer-aided comparison of folk music from different nations is one of the newest research areas. We were intrigued to have identified some important similarities between phylogenetic studies and modern folk music. First of all, both of them use similar concepts and representation tools such as multidimensional scaling for modelling relationship between populations. This gave us the idea to investigate whether these connections are merely accidental or if they mirror population migrations from the past. We raised the question; does the complex structure of musical connections display a clear picture and can this system be interpreted by the genetic analysis? This study is the first to systematically investigate the incidental genetic background of the folk music context between different populations. Paternal (42 populations) and maternal lineages (56 populations) were compared based on Fst genetic distances of the Y chromosomal and mtDNA haplogroup frequencies. To test this hypothesis, the corresponding musical cultures were also compared using an automatic overlap analysis of parallel melody styles for 31 Eurasian nations. We found that close musical relations of populations indicate close genetic distances (<0.05) with a probability of 82%. It was observed that there is a significant correlation between population genetics and folk music; maternal lineages have a more important role in folk music traditions than paternal lineages. Furthermore, the combination of these disciplines establishing a new interdisciplinary research field of "music-genetics" can be an efficient tool to get a more comprehensive picture on the complex behaviour of populations in prehistoric time.

  14. Comparative study of visual pathways in owls (Aves: Strigiformes).

    PubMed

    Gutiérrez-Ibáñez, Cristián; Iwaniuk, Andrew N; Lisney, Thomas J; Wylie, Douglas R

    2013-01-01

    Although they are usually regarded as nocturnal, owls exhibit a wide range of activity patterns, from strictly nocturnal, to crepuscular or cathemeral, to diurnal. Several studies have shown that these differences in the activity pattern are reflected in differences in eye morphology and retinal organization. Despite the evidence that differences in activity pattern among owl species are reflected in the peripheral visual system, there has been no attempt to correlate these differences with changes in the visual regions in the brain. In this study, we compare the relative size of nuclei in the main visual pathways in nine species of owl that exhibit a wide range of activity patterns. We found marked differences in the relative size of all visual structures among the species studied, both in the tectofugal and the thalamofugal pathway, as well in other retinorecipient nuclei, including the nucleus lentiformis mesencephali, the nucleus of the basal optic root and the nucleus geniculatus lateralis, pars ventralis. We show that the barn owl (Tyto alba), a species widely used in the study of the integration of visual and auditory processing, has reduced visual pathways compared to strigid owls. Our results also suggest there could be a trade-off between the relative size of visual pathways and auditory pathways, similar to that reported in mammals. Finally, our results show that although there is no relationship between activity pattern and the relative size of either the tectofugal or the thalamofugal pathway, there is a positive correlation between the relative size of both visual pathways and the relative number of cells in the retinal ganglion layer.

  15. Comparative Study of Algorithms for Automated Generalization of Linear Objects

    NASA Astrophysics Data System (ADS)

    Azimjon, S.; Gupta, P. K.; Sukhmani, R. S. G. S.

    2014-11-01

    Automated generalization, rooted from conventional cartography, has become an increasing concern in both geographic information system (GIS) and mapping fields. All geographic phenomenon and the processes are bound to the scale, as it is impossible for human being to observe the Earth and the processes in it without decreasing its scale. To get optimal results, cartographers and map-making agencies develop set of rules and constraints, however these rules are under consideration and topic for many researches up until recent days. Reducing map generating time and giving objectivity is possible by developing automated map generalization algorithms (McMaster and Shea, 1988). Modification of the scale traditionally is a manual process, which requires knowledge of the expert cartographer, and it depends on the experience of the user, which makes the process very subjective as every user may generate different map with same requirements. However, automating generalization based on the cartographic rules and constrains can give consistent result. Also, developing automated system for map generation is the demand of this rapid changing world. The research that we have conveyed considers only generalization of the roads, as it is one of the indispensable parts of a map. Dehradun city, Uttarakhand state of India was selected as a study area. The study carried out comparative study of the generalization software sets, operations and algorithms available currently, also considers advantages and drawbacks of the existing software used worldwide. Research concludes with the development of road network generalization tool and with the final generalized road map of the study area, which explores the use of open source python programming language and attempts to compare different road network generalization algorithms. Thus, the paper discusses the alternative solutions for automated generalization of linear objects using GIS-technologies. Research made on automated of road network

  16. Evaluation systems for clinical governance development: a comparative study.

    PubMed

    Hooshmand, Elaheh; Tourani, Sogand; Ravaghi, Hamid; Ebrahimipour, Hossein

    2014-01-01

    Lack of scientific and confirmed researches and expert knowledge about evaluation systems for clinical governance development in Iran have made studies on different evaluation systems for clinical governance development a necessity. These studies must provide applied strategies to design criteria of implementing clinical governance for hospital's accreditation. This is a descriptive and comparative study on development of clinical governance models all over the world. Data have been gathered by reviewing related articles. Models have been studied in comprehensive review method. The evaluated models of clinical governance development were Australian, NHS, SPOCK and OPTIGOV. The final aspects extracted from these models were Responsiveness, Policies and Strategies, Organizational Structure, Allocating Resources, Education and Occupational Development, Performance Evaluation, External Evaluation, Patient Oriented Approach, Risk Management, Personnel's Participation, Information Technology, Human Resources, Research and Development, Evidence Based Medicine, Clinical Audit, Health Technology Assessment and Quality. These results are applicable for completing the present criteria which evaluating clinical governance application and provide practical framework to evaluate country's hospital on the basis of clinical governance elements.

  17. Institutions and national development in Latin America: a comparative study.

    PubMed

    Portes, Alejandro; Smith, Lori D

    We review the theoretical and empirical literatures on the role of institutions on national development as a prelude to present a more rigorous and measurable definition of the concept and a methodology to study this relationship at the national and subnational levels. The existing research literature features conflicting definitions of the concept of "institutions" and empirical tests based mostly on reputational indices, with countries as units of analysis. The present study's methodology is based on a set of five strategic organizations studied comparatively in five Latin American countries. These include key federal agencies, public administrative organizations, and stock exchanges. Systematic analysis of results show a pattern of differences between economically-oriented institutions and those entrusted with providing basic services to the general population. Consistent differences in institutional quality also emerge across countries, despite similar levels of economic development. Using the algebraic methods developed by Ragin, we test six hypotheses about factors determining the developmental character of particular institutions. Implications of results for theory and for methodological practices of future studies in this field are discussed.

  18. A comparative study of road traffic accidents in West Malaysia.

    PubMed Central

    Silva, J. F.

    1978-01-01

    The problem of road traffic accidents in developing countries is now becoming a cause for concern. This is more so as preventive measures have not kept pace with economic progress and development. This paper reviews the present situation in West Malaysia, one of the better developed countries of the East, during the period 1970 to 1975. A comparative study has been made between the United States and Malaysia. To enable the urgency of the problem in developing countries to be appreciated the increases in the country's population and in the number of vehicles in use and their relation to the lesser increase in road mileage over the period of study have been discussed. The study has considered every aspect of the causative factors leading to traffic accidents, such as the effects of weather, seasonal variation, and road and lighting conditions. The common human errors leading to accidents have been discussed. Other factors, such as the ethnic distribution in Malaysia, and their relation to road accidents have shown the effect of the social structure on the problems. The data evaluated in this study make it clear that preventive measures are very necessary in underdeveloped as well as in developed countries. PMID:718073

  19. A comparative study of road traffic accidents in West Malaysia.

    PubMed

    Silva, J F

    1978-11-01

    The problem of road traffic accidents in developing countries is now becoming a cause for concern. This is more so as preventive measures have not kept pace with economic progress and development. This paper reviews the present situation in West Malaysia, one of the better developed countries of the East, during the period 1970 to 1975. A comparative study has been made between the United States and Malaysia. To enable the urgency of the problem in developing countries to be appreciated the increases in the country's population and in the number of vehicles in use and their relation to the lesser increase in road mileage over the period of study have been discussed. The study has considered every aspect of the causative factors leading to traffic accidents, such as the effects of weather, seasonal variation, and road and lighting conditions. The common human errors leading to accidents have been discussed. Other factors, such as the ethnic distribution in Malaysia, and their relation to road accidents have shown the effect of the social structure on the problems. The data evaluated in this study make it clear that preventive measures are very necessary in underdeveloped as well as in developed countries.

  20. Antiamoebic chemoprophylaxis using quinfamide in children: a comparative study.

    PubMed

    Padilla, Nicolas; Diaz, Rosalinda; Alarcon, Alfonso; Barreda, Roberto

    2002-04-20

    This study sought to examine whether the administration of quinfamide at 3- or 6-month intervals diminished the frequency of Entamoeba histolytica cysts in stool samples compared to controls. The prospective, longitudinal, randomized, single-blind study examined children from six primary schools in Celaya and Neutla, Guanajuato. Of the 1,524 students in these schools, we selected participants for the study as follows: Children were included in the study if their parents agreed in writing to the study and if the children demonstrated evidence of E. histolytica cysts after a parasitoscopic analysis by concentration (PSC) in three samples over consecutive days using Faust"s method. Those included in the study received a single 4.3-g/kg dose of quinfamide, and we performed PSC on days 5, 6, and 7 following dose administration to examine whether quinfamide had affected the presence of the cysts. The study participants who tested negative for cysts were divided into three groups: Group 1 had 102 patients who underwent quinfamide treatment and three CPS analyses after the 12 months of the study; Group 2 had 98 subjects who underwent the quinfamide treatment and three CPS analyses at months 3, 6, 9, and 12 after their entrance into the study; and Group 3 had 102 patients, who underwent the quinfamide treatment and series of three CPS analyses at months 6 and 12 of the study. All participants received the dose of quinfamide after providing stool samples and after a clinical gastrointestinal history was obtained. Further clinical gastrointestinal data were collected 5 days after the quintamide dose was administered. We used EpiInfo 6.0 for statistical analysis, calculating c2 and p values for the clinical data and the CPS data after the 12 months concluded. Of the initial samples of 1,524 subjects, 308 (20.2%) had Entamoebic cysts. Of these, six were further eliminated because they did not meet the inclusion requirements. At the conclusion of the study, Group 1 presented

  1. Texture analysis of multiple sclerosis: a comparative study.

    PubMed

    Zhang, Jing; Tong, Longzheng; Wang, Lei; Li, Ning

    2008-10-01

    The difficulty of using magnetic resonance imaging (MRI) to support early diagnosis of multiple sclerosis (MS) stems from the subtle pathological changes in the central nervous system (CNS). In this study, texture analysis was performed on MR images of MS patients and normal controls and a combined set of texture features were explored in order to better discriminate tissues between MS lesions, normal appearing white matter (NAWM) and normal white matter (NWM). Features were extracted from gradient matrix, run-length (RL) matrix, gray level co-occurrence matrix (GLCM), autoregressive (AR) model and wavelet analysis, and were selected based on greatest difference between different tissue types. The results of the combined set of texture features were compared with our previous results of GLCM-based features alone. The results of this study demonstrated that (1) with the combined set of texture features, classification was perfect (100%) between MS lesions and NAWM (or NWM), less successful (88.89%) among the three tissue types and worst (58.33%) between NAWM and NWM; (2) compared with GLCM-based features, the combined set of texture features were better at discriminating MS lesions and NWM, equally good at discriminating MS lesions and NAWM and at all three tissue types, but less effective in classification between NAWM and NWM. This study suggested that texture analysis with the combined set of texture features may be equally good or more advantageous than the commonly used GLCM-based features alone in discriminating MS lesions and NWM/NAWM and in supporting early diagnosis of MS.

  2. Epidural analgesia during labor vs no analgesia: A comparative study

    PubMed Central

    Mousa, Wesam Farid; Al-Metwalli, Roshdi; Mostafa, Manal

    2012-01-01

    Background: Epidural analgesia is claimed to result in prolonged labor. Previous studies have assessed epidural analgesia vs systemic opioids rather than to parturients receiving no analgesia. This study aimed to evaluate the effect of epidural analgesia on labor duration compared with parturients devoid of analgesia. Methods: One hundred sixty nulliparous women in spontaneous labor at full term with a singleton vertex presentation were assigned to the study. Parturients who request epidural analgesia were allocated in the epidural group, whereas those not enthusiastic to labor analgesia were allocated in the control group. Epidural analgesia was provided with 20 mL bolus 0.5% epidural lidocaine plus fentanyl and maintained at 10 mL for 1 h. Duration of the first and second stages of labor, number of parturients receiving oxytocin, maximal oxytocin dose required for each parturient, numbers of instrumental vaginal, vacuum-assisted, and cesarean deliveries and neonatal Apgar score were recorded. Results: There was no statistical difference in the duration of the active-first and the second stages of labor, instrumental delivery, vacuum-assisted or cesarean delivery rates, the number of newborns with 1-min and 5-min Apgar scores less than 7 between both groups and number of parturients receiving oxytocin, however, the maximal oxytocin dose was significantly higher in the epidural group. Conclusion: Epidural analgesia by lidocaine (0.5%) and fentanyl does not prolong labor compared with parturients without analgesia; however, significant oxytocin augmentation is required during the epidural analgesia to keep up the aforementioned average labor duration. PMID:22412775

  3. Comparative study of muscle regeneration following cardiotoxin and glycerol injury.

    PubMed

    Mahdy, Mohamed A A; Lei, Hsiao Yin; Wakamatsu, Jun-Ichi; Hosaka, Yoshinao Z; Nishimura, Takanori

    2015-11-01

    In the present study, we examined muscle regeneration following two types of chemical injuries, cardiotoxin (CTX) and glycerol, in order to compare their effect on the morphological characteristics during muscle regeneration, in addition we studied the structural changes of the intramuscular connective tissue (IMCT) during the regeneration process, by scanning electron microscopy (SEM) after digestion of the cellular elements of the muscle with sodium hydroxide. Tibialis anterior (TA) muscles of adult male mice were injected either with CTX or glycerol. Muscle degeneration was greater in the CTX-injured model than in the glycerol-injured model at day 4 post injection. Muscle regeneration started at day 7 in both the CTX and glycerol models. However, the CTX-injured model showed a higher myotube density and larger myotube diameter than the glycerol-injured model at days 10 and 14 post injection. On other hand, adipocyte infiltration was detected in the glycerol-injured model. In contrast, no adipocytes could be detected in the CTX-injured model. Furthermore, ultrastructural analysis showed a significant difference in myofiber damage and regeneration between the two models. SEM of the IMCT showed a transient increase in endomysial collagen deposition at early stages of regeneration in the CTX-injured model. In contrast, glycerol-injured model showed slight endomysial collagen deposition. Our results suggest that changes in IMCT affect the efficiency of muscle regeneration. Studying the three dimensional structure of IMCT may help clinical therapies to reduce skeletal muscle fibrosis. To our knowledge this is the first time the changes in IMCT following CTX and glycerol injury using SEM-cell maceration technique have been compared.

  4. Contrasting tropical estuarine ecosystem functioning and stability: A comparative study

    NASA Astrophysics Data System (ADS)

    Villanueva, Maria Ching

    2015-03-01

    A comparative study of the Sine-saloum (Senegal) and Gambia (The Gambia) estuaries was performed based on trophic model outputs that describe the system structure and functioning. These trophic models were constructed such as to differentiate main energetic flows in the systems and express how climate change may have impacted ecosystem resilience to change. Estuarine fish assemblages are highly resilient despite exposure to vast hydrodynamic variations and stress. Coupled with strong anthropogenic-driven stresses such as fisheries and climate change, ecosystems may undergo severe regime shifts that may weaken their resilience and stability. Taxonomically related and morphologically similar species do not necessarily play similar ecological roles in these two ecosystems. Biomass and production in the Sine-saloum are concentrated at trophic levels (TLs) 2 and 3, while for the Gambia, both are concentrated at TL3. Higher TL biomasses in Gambia compared to Sine-Saloum may be explained by the latter ecosystem being characterized by inverse hypersalinity. Higher TL of production in Sine-Saloum is due to higher exploitations compared to Gambia where fishing activities are still less developed. High production and consumption rates of some groups in both ecosystems indicate high system productivity. Elevated productivity may be due to higher abundance of juvenile fishes in most groups that utilize the latter as refuge and/or nursery zones. Both ecosystems are phytoplankton-driven. Differences in group trophic and ecological roles are mainly due to adaptive responses of these species to seasonal and long-term climate and anthropogenic stressors. System indicators suggest different levels of ecosystem resilience and stability as a function of biodiversity. Relevance of other observations on ecosystem functioning and indicators in relation to perturbation is discussed.

  5. Early parenting styles and sexual offending behavior: A comparative study.

    PubMed

    Sigre-Leirós, Vera; Carvalho, Joana; Nobre, Pedro J

    2016-01-01

    Sexual offenders, in general, report problematic rearing practices from their parents, lacking however more empirical research on this topic regarding particular subtypes of offenders. The current study examined the relationship between early parenting styles and different types of sexual offending. A total of 113 sexual offenders (rapists, pedophilic and nonpedophilic child molesters), and 51 nonsexual offenders completed the EMBU (My Memories of Upbringing), the Brief Symptom Inventory, and the Socially Desirable Response Set Measure. Results showed that rapists were less likely to remember their fathers as being emotionally warm compared with nonsexual offenders and pedophilic child molesters. In addition, compared with rapists, pedophilic offenders perceived their mothers as having been less emotionally warm to them. Overall, results showed that certain developmental experiences with parents were able to distinguish between subtypes of offenders supporting an association between distal interpersonal factors and sexual offending. These findings may have important implications for early intervention and prevention of sexual crimes. Further research using larger samples of pedophilic child molesters is recommended.

  6. Colloidal Dispersions for the Delivery of Acyclovir: A Comparative Study

    PubMed Central

    Cortesi, Rita; Ravani, Laura; Menegatti, Enea; Drechsler, M.; Esposito, Elisabetta

    2011-01-01

    This paper describes a comparative study on the performances of ethosomes and solid lipid nanoparticle as delivery systems for acyclovir. Ethosomes were spontaneously produced by dissolution of phosphatidylcholine and acyclovir in ethanol followed by addition of an aqueous buffer while solid lipid nanoparticle were produced by homogenization and ultrasonication. Both colloidal systems were morphologically characterized by cryo-transmission electron microscopy. The encapsulation efficiency was 94.2±2.8% for ethosomes and 53.2±0.2% for solid lipid nanoparticle. Concerning Z potential, both formulations are close to neutrality. The diffusion coefficients of the drug from ethosomes and solid lipid nanoparticle, determined by a Franz cell method, were 9.4 and 1.2-fold lower as compared to the free acyclovir in solution, thus evidencing the ability of both colloidal systems in enhancing the diffusion of the drug. The antiviral activity against HSV-1 of both systems was tested by plaque reduction assay in monolayer cultures of Vero cells. Data showed that no significant differences in the antiviral activity were observed by acyclovir in the free or loaded forms. Taken together these results, colloidal systems could be interesting to mediate the penetration of acyclovir within Vero cells. PMID:23112407

  7. Colloidal dispersions for the delivery of acyclovir: a comparative study.

    PubMed

    Cortesi, Rita; Ravani, Laura; Menegatti, Enea; Drechsler, M; Esposito, Elisabetta

    2011-11-01

    This paper describes a comparative study on the performances of ethosomes and solid lipid nanoparticle as delivery systems for acyclovir. Ethosomes were spontaneously produced by dissolution of phosphatidylcholine and acyclovir in ethanol followed by addition of an aqueous buffer while solid lipid nanoparticle were produced by homogenization and ultrasonication. Both colloidal systems were morphologically characterized by cryo-transmission electron microscopy. The encapsulation efficiency was 94.2±2.8% for ethosomes and 53.2±0.2% for solid lipid nanoparticle. Concerning Z potential, both formulations are close to neutrality. The diffusion coefficients of the drug from ethosomes and solid lipid nanoparticle, determined by a Franz cell method, were 9.4 and 1.2-fold lower as compared to the free acyclovir in solution, thus evidencing the ability of both colloidal systems in enhancing the diffusion of the drug. The antiviral activity against HSV-1 of both systems was tested by plaque reduction assay in monolayer cultures of Vero cells. Data showed that no significant differences in the antiviral activity were observed by acyclovir in the free or loaded forms. Taken together these results, colloidal systems could be interesting to mediate the penetration of acyclovir within Vero cells.

  8. Erythrophagocytosis in Entamoeba histolytica and Entamoeba dispar: a comparative study.

    PubMed

    Talamás-Lara, Daniel; Chávez-Munguía, Bibiana; González-Robles, Arturo; Talamás-Rohana, Patricia; Salazar-Villatoro, Lizbeth; Durán-Díaz, Ángel; Martínez-Palomo, Adolfo

    2014-01-01

    Entamoeba histolytica is the causative agent of human intestinal and liver amebiasis. The extraordinary phagocytic activity of E. histolytica trophozoites has been accepted as one of the virulence mechanisms responsible for their invasive capacity. The recognition of the noninvasive Entamoeba dispar as a different species has raised the question as to whether the lack of pathogenic potential of this ameba correlates with a limited phagocytic capacity. We have therefore compared the process of erythrophagocytosis in both species by means of light and video microscopy, hemoglobin measurement, and the estimation of reactive oxygen species (ROS). In the present study, we confirmed that E. dispar has lower erythrophagocytic capacity. We also observed by video microscopy a new event of erythrocyte opsonization-like in both species, being more characteristic in E. histolytica. Moreover, E. dispar showed a lower capacity to produce ROS compared with the invasive species and also showed a large population of amoebae that did not engulf any erythrocyte over time. Our results demonstrate that E. histolytica has a higher phagocytic capacity than E. dispar, including a higher rate of production of ROS in the course of ingesting red blood cells.

  9. Erythrophagocytosis in Entamoeba histolytica and Entamoeba dispar: A Comparative Study

    PubMed Central

    Talamás-Lara, Daniel; Chávez-Munguía, Bibiana; González-Robles, Arturo; Talamás-Rohana, Patricia; Salazar-Villatoro, Lizbeth; Durán-Díaz, Ángel; Martínez-Palomo, Adolfo

    2014-01-01

    Entamoeba histolytica is the causative agent of human intestinal and liver amebiasis. The extraordinary phagocytic activity of E. histolytica trophozoites has been accepted as one of the virulence mechanisms responsible for their invasive capacity. The recognition of the noninvasive Entamoeba dispar as a different species has raised the question as to whether the lack of pathogenic potential of this ameba correlates with a limited phagocytic capacity. We have therefore compared the process of erythrophagocytosis in both species by means of light and video microscopy, hemoglobin measurement, and the estimation of reactive oxygen species (ROS). In the present study, we confirmed that E. dispar has lower erythrophagocytic capacity. We also observed by video microscopy a new event of erythrocyte opsonization-like in both species, being more characteristic in E. histolytica. Moreover, E. dispar showed a lower capacity to produce ROS compared with the invasive species and also showed a large population of amoebae that did not engulf any erythrocyte over time. Our results demonstrate that E. histolytica has a higher phagocytic capacity than E. dispar, including a higher rate of production of ROS in the course of ingesting red blood cells. PMID:25003123

  10. [Stereoscopic neuroanatomy: comparative study between anaglyphic and light polarization techniques].

    PubMed

    Meneses, Murilo Sousa; Cruz, André Vieira; Castro, Izara Almeida; Pedrozo, Ari A

    2002-09-01

    The need of didactic material is increasing in medical science nowadays. The lack of anatomical specimens, and the toxicity of conservators, have originated an intense search for alternative ways of demonstrating the human anatomy. As a solution for this difficulty, three-dimensional (3-D) images may be used, facilitating the learning process. This study aims at comparing and describing two techniques of reproduction of bi-dimensional images into three dimensions, which is called stereoscopy. The methods evaluated are filter of colors (anaglyphic) and polarized light. Techniques were analyzed for clearness and 3-D effect. Fourteen images were evaluated by 5 people, with scores ranging from 0 to 4. Total mean scores of polarized light was superior compared to the anaglyphic technique. Both methods use the codification of the image, which means separation and exclusivity with each eye seeing its corresponding image. After several photographic essays and gradual adaptation to a better technique, based on optical physics, photography and neuroanatomical knowledge, we concluded that both techniques are suitable means for production of 3-D images. The best technique, however, considering the final quality of image was polarized light, which did not alter the natural color of the specimen, conserving clearness of images with lower cost.

  11. A Comparative Study on Cutting Electrodes for Batteries with Lasers

    NASA Astrophysics Data System (ADS)

    Luetke, Matthias; Franke, Volker; Techel, Anja; Himmer, Thomas; Klotzbach, Udo; Wetzig, Andreas; Beyer, Eckhard

    E-mobility is still one of the most discussed topics within the automotive industry. Electric powered vehicles can drive emissionfree and present consequently the future propulsion. Nearly all global players in the automotive industry are making great efforts to develop cost-efficient electric drives, which are suitable for series production. The national governments support this evolution progressively. For example the mobility research programme of the Federal Republic of Germany looks at the production of Li- Ion cells in its entirety. Within this programme the cutting of electrodes for Li-Ion cells by lasers is an issue, too. This paper provides a comparative study on cutting materials relevant for Li-Ion cells with beam sources operating in a cw mode and a pulsed mode respectively.

  12. Advanced general aviation comparative engine/airframe integration study

    NASA Technical Reports Server (NTRS)

    Huggins, G. L.; Ellis, D. R.

    1981-01-01

    The NASA Advanced Aviation Comparative Engine/Airframe Integration Study was initiated to help determine which of four promising concepts for new general aviation engines for the 1990's should be considered for further research funding. The engine concepts included rotary, diesel, spark ignition, and turboprop powerplants; a conventional state-of-the-art piston engine was used as a baseline for the comparison. Computer simulations of the performance of single and twin engine pressurized aircraft designs were used to determine how the various characteristics of each engine interacted in the design process. Comparisons were made of how each engine performed relative to the others when integrated into an airframe and required to fly a transportation mission.

  13. A Comparative Characteristic Study of Jatropha and Cardanol Biodiesel Blends

    NASA Astrophysics Data System (ADS)

    Pugazhenthi, R.; Chandrasekaran, M.; Muthuraman, R. K.; Vivek, P.; Parthiban, A.

    2017-03-01

    The demand in fuel needs and the depleting fossil fuels raised the need towards bio-fuels. The emerging trend in research field is highly focused on biodiesel production and their characteristic analysis. Since pollution is a major threat to the environment, emission parameter analyses are much important to be concentrated. As the entire world contains plenty of biofuels, it is necessary to explore them for its efficiency and analyze their parameters. In this experimental work jatropha and cashew nut shell biodiesel (Cardanol) was extracted and they were blended with diesel. The characteristics of jatropha and cardanol biodiesel were studied in the DI diesel engine by varying the load at the same speed. In brief, this experimental analysis is carried out to compare the emission characteristics between Jatropha biodiesel at 20% (B20) and 40% (B40) and Cardanol biodiesel blends at 20% (C20) and 40% (C40).

  14. A Comparative Study of Phenols in Apulian Italian Wines.

    PubMed

    Ragusa, Andrea; Centonze, Carla; Grasso, Maria E; Latronico, Maria F; Mastrangelo, Pier F; Sparascio, Federica; Fanizzi, Francesco P; Maffia, Michele

    2017-03-24

    Nutraceutics is a growing research field in which researchers study and attempt to improve the biological properties of metabolites in food. Wine is one of the most consumed products in the world and contains a plethora of molecules biologically relevant to human health. In this article, several polyphenols with potential antioxidant activity were measured in wines from Apulia, in Southeast Italy. Hydroxytyrosol, gallic and syringic acids, luteolin, quercetin, and trans-resveratrol were identified and quantified by HPLC. The amount of the analyzed metabolites in wines were largely dependent on their color, with red ones being the richest compared to white and rose wines. Gallic acid was the most abundant polyphenol, followed by syringic acid and luteolin. Nevertheless, significant amounts of hydroxytyrosol, quercetin, and trans-resveratrol were also found. The average concentration of polyphenols found in these wines could have potential health-promoting effects, especially if consumed in moderate quantities on a regular basis.

  15. A Comparative Study of Distribution System Parameter Estimation Methods

    SciTech Connect

    Sun, Yannan; Williams, Tess L.; Gourisetti, Sri Nikhil Gup

    2016-07-17

    In this paper, we compare two parameter estimation methods for distribution systems: residual sensitivity analysis and state-vector augmentation with a Kalman filter. These two methods were originally proposed for transmission systems, and are still the most commonly used methods for parameter estimation. Distribution systems have much lower measurement redundancy than transmission systems. Therefore, estimating parameters is much more difficult. To increase the robustness of parameter estimation, the two methods are applied with combined measurement snapshots (measurement sets taken at different points in time), so that the redundancy for computing the parameter values is increased. The advantages and disadvantages of both methods are discussed. The results of this paper show that state-vector augmentation is a better approach for parameter estimation in distribution systems. Simulation studies are done on a modified version of IEEE 13-Node Test Feeder with varying levels of measurement noise and non-zero error in the other system model parameters.

  16. Interpreting odours in hermit crabs: A comparative study

    NASA Astrophysics Data System (ADS)

    Tricarico, Elena; Breithaupt, Thomas; Gherardi, Francesca

    2011-01-01

    Odours of different sources can indicate to hermit crabs the availability of empty shells, crucial resources for the life cycle of almost all of them. Here, we compared Clibanarius erythropus and Pagurus bernhardus for the intensity of investigative behaviour exhibited towards an empty, well-fitting shell in the presence of (1) plain seawater as control and seawater conditioned by (2) dead and live snails, (3) dead and live conspecifics, (4) live predators, and (5) food. During 10 min of observation, we recorded latency (the time until the first contact with the shell), and the number and duration of shell investigation bouts. The two species behaved similarly when exposed to the odours of food, live snails, and predators, while a more intense shell investigation was induced by dead snail odour in C. erythropus and by dead or live conspecific odour in P. bernhardus. Further studies should investigate the influence of phylogeny and ecology on this interspecific difference.

  17. MRI compatibility of robot actuation techniques--a comparative study.

    PubMed

    Fischer, Gregory S; Krieger, Axel; Iordachita, Iulian; Csoma, Csaba; Whitcomb, Louis L; Gabor, Fichtinger

    2008-01-01

    This paper reports an experimental evaluation of the following three different MRI-compatible actuators: a Shinsei ultrasonic motor a Nanomotion ultrasonic motor and a pneumatic cylinder actuator. We report the results of a study comparing the effect of these actuators on the signal to noise ratio (SNR) of MRJ images under a variety of experimental conditions. Evaluation was performed with the controller inside and outside the scanner room and with both 1.5T and 3T MRI scanners. Pneumatic cylinders function with no loss of SNR with controller both inside and outside of the scanner room. The Nanomotion motor performs with moderate loss of SNR when moving during imaging. The Shinsei is unsuitable for motion during imaging. All may be used when motion is appropriately interleaved with imaging cycles.

  18. Comparative studies in series of cytochrome c oxidase models.

    PubMed

    Melin, F; Trivella, A; Lo, M; Ruzié, C; Hijazi, I; Oueslati, N; Wytko, J A; Boitrel, B; Boudon, C; Hellwig, P; Weiss, J

    2012-03-01

    This study compares the behavior as cytochrome c oxidase (CcO) functional and structural models of a series of reported and unreported ligands that provide either a binding site for copper without a built-in proximal base, or both a flexible binding site for copper and a built-in proximal base, or a fixed binding site for copper with a built-in proximal base. The comparisons of the models show that the relative position of the two metal sites is not only a crucial parameter in the control of the catalytic behavior but also essential in mimicking other features of the enzyme such as CO exchange between the ferrous heme a(3) and the cuprous Cu(B) center.

  19. A comparative study of two stochastic mode reduction methods

    SciTech Connect

    Stinis, Panagiotis

    2005-09-01

    We present a comparative study of two methods for thereduction of the dimensionality of a system of ordinary differentialequations that exhibits time-scale separation. Both methods lead to areduced system of stochastic differential equations. The novel feature ofthese methods is that they allow the use, in the reduced system, ofhigher order terms in the resolved variables. The first method, proposedby Majda, Timofeyev and Vanden-Eijnden, is based on an asymptoticstrategy developed by Kurtz. The second method is a short-memoryapproximation of the Mori-Zwanzig projection formalism of irreversiblestatistical mechanics, as proposed by Chorin, Hald and Kupferman. Wepresent conditions under which the reduced models arising from the twomethods should have similar predictive ability. We apply the two methodsto test cases that satisfy these conditions. The form of the reducedmodels and the numerical simulations show that the two methods havesimilar predictive ability as expected.

  20. A comparative study of two different clear aligner systems

    PubMed Central

    2014-01-01

    Background This study aims to compare the ‘Nuvola®’ system with ‘Fantasmino®’ system, examine their material properties, and define the indications for use of the aligners. Methods Two groups of patients were selected and were respectively treated with Nuvola® aligner and Fantasmino® system. Results The goal of treatment has been achieved with the two systems. Conclusions The two types of aligners have shown differences during the treatment. Fantasmino® system has elastic properties of high performance, but its size does not encourage compliance throughout the day. Nuvola® system determines good tooth movement and its size facilitates the patient’s collaboration. In both aligner systems, difficulties were found in the correction of torque information and rotations. PMID:24934094

  1. Comparing the Leadership Styles of Two Heads of Department at Carnelian School: Comparative Case Studies

    ERIC Educational Resources Information Center

    Parascandalo, Marthese

    2014-01-01

    The purpose of this dissertation was to compare and contrast the Leadership Styles of two Heads of Department who work at Carnelian Secondary School (anonymized). It augments a previous paper (Parascandalo 2011) which examined the role of the middle leader in secondary schools in educational literature. The investigation by means of two…

  2. Skin condition assessment: a comparative study of techniques

    NASA Astrophysics Data System (ADS)

    Bindra, Ravindar M.; Wong, Joretta K.; Andrew, Jeremy J.; Xiao, Peng; Zhang, Bufa; Imhof, Robert E.

    1996-05-01

    We report the results of a study aimed at comparing Opto-Thermal Transient Emission Radiometry (OTTER) with established techniques of assessing skin condition, namely evaporimetry (TEWL), skin dielectric constant measurement, ATR-FTIR and clinical assessment. Comparisons were made during a week-long study of the effects of intensive washing on the volar forearms of 14 subjects. The study also provided a comparison of skin condition after washing with two different cleansers, a mild isethionate betaine cleansing bar and a soap bar. The subject-averaged results from OTTER and TEWL were found to correlate with the clinical assessments, namely that intensive washing with the soap bar produces greater skin damage than with the isethionate betaine bar. Skin dielectric constant measurements were found to be sensitive to changes of skin condition other than hydration, as evidenced by a daily oscillation that dominate the results. The ATR-FTIR measurements proved difficult to evaluate, because of interfering calcium deposits from the soap bar. On the practical side, OTTER and skin dielectric constant measurements were found to be quicker and more convenient to use than TEWL and ATR-FTIR.

  3. The comparative study of solvents to expedite removal of bitumen.

    PubMed

    Iuchi, Manabu; Sugiyama, Masahide; Oyatsu, Yasuyuki; Fukai, Takao

    2009-03-01

    Hot-bitumen burn is a unique case in all types of burns. This melting substance is difficult to remove when it adheres to the skin and solidifies. It causes burns and sticks to the skin when it is cooled to the skin temperature. Some reports are available on many kinds of solvents for the removal of solid bitumen. However, there have thus far been no comparative studies. It is necessary to seek for an optimum method to remove bitumen without consuming so much time and with minimum injury to the skin. The selected solvents in this study were petrolatum, olive oil, salad oil, butter, Neosporin ointment and De-solv-it. They were often reported as being effective for hot-bitumen burn injuries with little irritation for a damaged skin. It is easy to purchase them commercially. Each solvent was poured over the bitumen in a test tube. Afterwards, the concentrations of the bitumen in the solvents were quantified with the fluorescence measurement technique. We consider De-solv-it is the one of the best solvent for the removal of bitumen and highly recommended for hot-bitumen burns. The results of this study suggest that dressing change should be done every 4 to 8 h or as frequently as needed until the bitumen is entirely removed.

  4. Comparative study of heuristic evaluation and usability testing methods.

    PubMed

    Thyvalikakath, Thankam Paul; Monaco, Valerie; Thambuganipalle, Himabindu; Schleyer, Titus

    2009-01-01

    Usability methods, such as heuristic evaluation, cognitive walk-throughs and user testing, are increasingly used to evaluate and improve the design of clinical software applications. There is still some uncertainty, however, as to how those methods can be used to support the development process and evaluation in the most meaningful manner. In this study, we compared the results of a heuristic evaluation with those of formal user tests in order to determine which usability problems were detected by both methods. We conducted heuristic evaluation and usability testing on four major commercial dental computer-based patient records (CPRs), which together cover 80% of the market for chairside computer systems among general dentists. Both methods yielded strong evidence that the dental CPRs have significant usability problems. An average of 50% of empirically-determined usability problems were identified by the preceding heuristic evaluation. Some statements of heuristic violations were specific enough to precisely identify the actual usability problem that study participants encountered. Other violations were less specific, but still manifested themselves in usability problems and poor task outcomes. In this study, heuristic evaluation identified a significant portion of problems found during usability testing. While we make no assumptions about the generalizability of the results to other domains and software systems, heuristic evaluation may, under certain circumstances, be a useful tool to determine design problems early in the development cycle.

  5. Institutions and national development in Latin America: a comparative study

    PubMed Central

    Portes, Alejandro; Smith, Lori D.

    2013-01-01

    We review the theoretical and empirical literatures on the role of institutions on national development as a prelude to present a more rigorous and measurable definition of the concept and a methodology to study this relationship at the national and subnational levels. The existing research literature features conflicting definitions of the concept of “institutions” and empirical tests based mostly on reputational indices, with countries as units of analysis. The present study’s methodology is based on a set of five strategic organizations studied comparatively in five Latin American countries. These include key federal agencies, public administrative organizations, and stock exchanges. Systematic analysis of results show a pattern of differences between economically-oriented institutions and those entrusted with providing basic services to the general population. Consistent differences in institutional quality also emerge across countries, despite similar levels of economic development. Using the algebraic methods developed by Ragin, we test six hypotheses about factors determining the developmental character of particular institutions. Implications of results for theory and for methodological practices of future studies in this field are discussed. PMID:26543407

  6. Modelling effects of internalized antibody: a simple comparative study

    PubMed Central

    2014-01-01

    Background The modelling framework is proposed to study protection properties of antibodies to neutralize the effects of the plant toxin (ricin). The present study extends our previous work by including (i) the model of intracellular transport of toxin to the Endoplasmic Reticulum and (ii) the model of the internalised antibodies (when antibody is delivered directly into the cytosol). Method Simulation of the receptor-toxin-antibody interaction is implemented by solving the systems of PDEs (advection-diffusion models) or ODEs (rate models) for the underlying transport coupled with mass-action kinetics. Results As the main application of the enhanced framework we present a comparative study of two kinds (external and internalised) of antibodies. This comparison is based on calculation of the non-dimensional protection factor using the same set of parameters (geometry, binding constants, initial concentrations of species, and total initial amount of the antibody). Conclusion This research will provide a framework for consistent evaluation and comparison of different types of antibodies for toxicological applications. PMID:24521456

  7. Extreme storm surges: a comparative study of frequency analysis approaches

    NASA Astrophysics Data System (ADS)

    Hamdi, Y.; Bardet, L.; Duluc, C.-M.; Rebour, V.

    2014-08-01

    In France, nuclear facilities were designed around very low probabilities of failure. Nevertheless, some extreme climatic events have given rise to exceptional observed surges (outliers) much larger than other observations, and have clearly illustrated the potential to underestimate the extreme water levels calculated with the current statistical methods. The objective of the present work is to conduct a comparative study of three approaches to extreme value analysis, including the annual maxima (AM), the peaks-over-threshold (POT) and the r-largest order statistics (r-LOS). These methods are illustrated in a real analysis case study. All data sets were screened for outliers. Non-parametric tests for randomness, homogeneity and stationarity of time series were used. The shape and scale parameter stability plots, the mean excess residual life plot and the stability of the standard errors of return levels were used to select optimal thresholds and r values for the POT and r-LOS method, respectively. The comparison of methods was based on (i) the uncertainty degrees, (ii) the adequacy criteria and tests, and (iii) the visual inspection. It was found that the r-LOS and POT methods have reduced the uncertainty on the distribution parameters and return level estimates and have systematically shown values of the 100 and 500-year return levels smaller than those estimated with the AM method. Results have also shown that none of the compared methods has allowed a good fit at the right tail of the distribution in the presence of outliers. As a perspective, the use of historical information was proposed in order to increase the representativeness of outliers in data sets. Findings are of practical relevance, not only to nuclear energy operators in France, for applications in storm surge hazard analysis and flood management, but also for the optimal planning and design of facilities to withstand extreme environmental conditions, with an appropriate level of risk.

  8. Extreme storm surges: a comparative study of frequency analysis approaches

    NASA Astrophysics Data System (ADS)

    Hamdi, Y.; Bardet, L.; Duluc, C.-M.; Rebour, V.

    2013-11-01

    In France, nuclear facilities were designed to very low probabilities of failure. Nevertheless, exceptional climatic events have given rise to surges much larger than observations (outliers) and had clearly illustrated the potential to underestimate the extreme water levels calculated with the current statistical methods. The objective of the present work is to conduct a comparative study of three approaches including the Annual Maxima (AM), the Peaks-Over Threshold (POT) and the r-Largest Order Statistics (r-LOS). These methods are illustrated in a real analysis case study. All the data sets were screened for outliers. Non-parametric tests for randomness, homogeneity and stationarity of time series were used. The shape and scale parameters stability plots, the mean excess residual life plot and the stability of the standard errors of return levels were used to select optimal thresholds and r values for the POT and r-LOS method, respectively. The comparison of methods was based on: (i) the uncertainty degrees, (ii) the adequacy criteria and tests and (iii) the visual inspection. It was found that the r-LOS and POT methods have reduced the uncertainty on the distributions parameters and return level estimates and have systematically shown values of the 100 and 500 yr return levels smaller than those estimated with the AM method. Results have also shown that none of the compared methods has allowed a good fitting at the right tail of the distribution in the presence of outliers. As a perspective, the use of historical information was proposed in order to increase the representativity of outliers in data sets. Findings are of practical relevance not only to nuclear energy operators in France, for applications in storm surge hazard analysis and flood management, but also for the optimal planning and design of facilities to withstand extreme environmental conditions, with an appropriate level of risk.

  9. Systemic Inflammation in Cardiovascular and Periodontal Disease: Comparative Study

    PubMed Central

    Glurich, Ingrid; Grossi, Sara; Albini, Boris; Ho, Alex; Shah, Rashesh; Zeid, Mohamed; Baumann, Heinz; Genco, Robert J.; De Nardin, Ernesto

    2002-01-01

    Epidemiological studies have implicated periodontal disease (PD) as a risk factor for the development of cardiovascular disease (CVD). These studies addressed the premise that local infection may perturb the levels of systemic inflammatory mediators, thereby promoting mechanisms of atherosclerosis. Levels of inflammatory mediators in the sera of subjects with only PD, only CVD, both diseases, or neither condition were compared. Subjects were assessed for levels of C-reactive protein (CRP), serum amyloid A (SAA), ceruloplasmin, α1-acid-glycoprotein (AAG), α1-antichymotrypsin (ACT), and the soluble cellular adhesion molecules sICAM-1 and sVCAM by enzyme-linked immunoabsorbent and/or radial immunodiffusion assays. CRP levels in subjects with either condition alone were elevated twofold above subjects with neither disease, whereas a threefold increase was noted in subjects with both diseases (P = 0.0389). Statistically significant increases in SAA and ACT were noted in subjects with both conditions compared to those with one or neither condition (P = 0.0162 and 0.0408, respectively). Ceruloplasmin levels were increased in subjects with only CVD (P = 0.0001). Increases in sVCAM levels were noted in all subjects with CVD (P = 0.0054). No differences in sICAM levels were noted among subject groups. A trend toward higher levels of AAG was noted in subjects with both conditions and for ACT in subjects with only PD. Immunohistochemical examination of endarterectomy specimens of carotid arteries from subjects with atherosclerosis documented SAA and CRP deposition in association with atheromatous lesions. The data support the hypothesis that localized persistent infection may influence systemic levels of inflammatory mediators. Changes in inflammatory mediator levels potentially impact inflammation-associated atherosclerotic processes. PMID:11874889

  10. Comparative studies of brain activation with MEG and functional MRI

    SciTech Connect

    George, J.S.; Aine, C.J.; Sanders, J.A.; Lewine, J.D.; Caprihan, A.

    1993-12-31

    The past two years have witnessed the emergence of MRI as a functional imaging methodology. Initial demonstrations involved the injection of a paramagnetic contrast agent and required ultrafast echo planar imaging capability to adequately resolve the passage of the injected bolus. By measuring the local reduction in image intensity due to magnetic susceptibility, it was possible to calculate blood volume, which changes as a function of neural activation. Later developments have exploited endogenous contrast mechanisms to monitor changes in blood volume or in venous blood oxygen content. Recently, we and others have demonstrated that it is possible to make such measurements in a clinical imager, suggesting that the large installed base of such machines might be utilized for functional imaging. Although it is likely that functional MRI (fMRI) will subsume some of the clinical and basic neuroscience applications now touted for MEG, it is also clear that these techniques offer different largely complementary, capabilities. At the very least, it is useful to compare and cross-validate the activation maps produced by these techniques. Such studies will be valuable as a check on results of neuromagnetic distributed current reconstructions and will allow better characterization of the relationship between neurophysiological activation and associated hemodynamic changes. A more exciting prospect is the development of analyses that combine information from the two modalities to produce a better description of underlying neural activity than is possible with either technique in isolation. In this paper we describe some results from initial comparative studies and outline several techniques that can be used to treat MEG and fMRI data within a unified computational framework.

  11. Comparative studies on nitrogen budgets of closed shrimp polyculture systems

    NASA Astrophysics Data System (ADS)

    Qi, Zhen-Xiong; Li, De-Shang; Zhang, Man-Ping; Dong, Shuang-Lin

    2001-09-01

    April to October, 1997 comparative studies on the nitrogen budgets of closed shrimp polyculture systems showed that, in all the studied polyculture systems, nitrogen from feeds and fertilizers were the main input items, which comprised 70.7% 83.9% of the total input nitrogen 3.2% 7.4% of which was provided by nitrogen fixation. It was in monoculture enclosures (Y-4, Y-11 and Y-12) that the percentage reached the maximum value. The output nitrogen in harvested products comprised 10.8% 24.6% of total input nitrogen, and the highest percentage, 24.6%, was found in shrimp-fish-tagelus polyculture systems. In shrimp monoculture and shrimp-fish polyculture systems, they were 19.1% and 21.9% respectively. The nitrogen utilization efficiency was different and varied from 12.2% was found in shrimp-tagelus polyculture systems. The lowest, 12.2%, was found in shrimp monoculture systems. All the nitrogen utilization efficiencies in shrimp-fish systems or shrimp-scallop systems seemed to be higher than that of the monoculture system, but they showed little statistical difference. The main outputs of nitrogen were found in sediment mud, and comprised 48.2% 60.8% of the total, input, the lowest percentage was found in shrimp-fish-tagelus polyculture systems, and the highest percentage in shrimp-scallop systems. During the experiment, nitrogen lost through denitrification and ammonia volatilization comprised 1.9% 6. 2%, averaged 2.8%, of the total input, and the loss through seepage comprised 5.9% 8.9% of the total. The estimated nitrogen attached to the enclosure wall comprised 3.7% 13.3% of the total, and was highest in shrimp monoculture systems. Compared with the classic shrimp farming industry, the closed shrimp polyculture systems may improve the nitrogen utilization efficiency, and hence reduce the environmental impacts on coastal waters. The nitrogen discharging rates for all the studied polyculture systems ranged from 3.0% to 6. 0% of total input nitrogen.

  12. An open multicenter comparative randomized clinical study on chitosan.

    PubMed

    Mo, Xiaohui; Cen, John; Gibson, Elaine; Wang, Robin; Percival, Steven L

    2015-01-01

    Chitosan, a natural polysaccharide derivate from chitin, offers a promising alternative biomaterial for use in wound dressings. In this work, the safety and efficacy of a next-generation KA01 chitosan wound dressing in facilitating the healing of nonhealing chronic wounds was studied. This open multicenter comparative prospective randomized clinical study was conducted at three medical centers in China. A total of 90 patients (45 in test group and 45 in control group) with unhealed chronic wounds including pressure ulcers, vascular ulcers, diabetic foot ulcers, and wounds with minor infections, or at risk of infection, were treated with the next generation chitosan wound dressing as the test article or traditional vaseline gauze as a control. Baseline assessments were undertaken with the primary end point being wound area reduction. The secondary end points included pain reduction (using the NRS11 pain scale) at dressing change, wound exudate levels, wound depth and duration of the treatment. After 4 weeks treatment, the wound area reduction was significantly greater in the test group (65.97 ± 4.48%) than the control group (39.95 ± 4.48%). The average pain level in the test group was 1.12 ± 0.23 and 2.30 ± 0.23 in the control group. The wound depth was also lower in the test group 0.30 ± 0.48 cm than the control group 0.54 ± 0.86 cm. The level of exudate fell and the dressing could be removed integrally in both the test and control groups. The mean duration of the test group was 27.31 ± 5.37 days and control group 27.09 ± 6.44 days. No adverse events were reported in either group. In conclusion this open multicenter comparative prospective randomized clinical study has provided compelling evidence that the next generation chitosan wound dressing can enhance wound progression towards healing by facilitating wound reepithelialization and reducing the patients pain level. Furthermore the dressing was shown to be clinically safe and effective in the management

  13. Comparative study of energetic heliospheric electrons at wind and geotail

    NASA Technical Reports Server (NTRS)

    Chaizy, P. A.; Lanzerotti, L. J.; Lin, R. P.; Lepping, R. P.; Kokubun, S. K.; Bosqued, J.-M.; Sanderson, T. R.; Yamamoto, T.

    1997-01-01

    The current fleet of both heliospheric and magnetospheric spacecraft provides a unique opportunity of studying spatio-temporal plasma phenomena. Among the numerous topics that can be addressed by such a fleet, figures the 3D study of energetic (greater than 20 keV) solar electron) solar electron events. WIND and GEOTAIL are particulary interesting for such analysis: more than two years of data; up to 3/4 continuous days spent by GEOTAIL in the solar wind; and comparable experiments. During solar electron events, rapid electron flux changes can be associated with these structures. Sometimes they are seen at both spacecraft with a time difference corresponding to the convection time, but sometimes they are observed at one spacecraft but not at the other. Several preliminary conclusions can be drawn from such events: (1) there is direct evidence that, within distances lower than 1.5 x 10(exp 6) km at 1 A (approximately 7000 km at the sun), there are significant spatial variations of (a) the magnetic field line connections to the source region and probably of (b) the particle propagation features; (2) magnetic field lines inside and outside particle propagation structures can keep distinct access to the source region for more than one hour; (3) flux waves, of probable local origin, were observed; and (4) within one hour, spatial flux discrepancies, separated by magnetic structures, may remain or disappear.

  14. Comparative studies on the status of Indonesian coral reefs

    NASA Astrophysics Data System (ADS)

    Soekarno, R.

    Coral reefs are of great economic importance for Indonesia. Unfortunately these resources are suffering from increasing human pressure. Several factors may cause the degradation of coral reefs, including the consequences of several human activities. Activities indirectly affecting the quality of the reefs are land-based activities such as deforestation, agriculture intensification, industrialization and domestic waste disposal. Direct use of the reefs, e.g. by coral mining, fish blasting and other fishing and collecting activities, is of greater and more widespread importance. Therefore, a rational management of the reef resources is urgently needed. Management is impossible without simple means of monitoring the status of reefs. One factor, living coral cover, has been determined for several years in many areas, including those studied during the Snellius-II Expedition. This allowed a comparative study of several different areas, which showed that coral cover is often very useful as an indication of the quality of reefs. It was found that the diversity of reef fishes is correlated with the condition of reefs as determined by the percentage cover of living coral.

  15. Comparative Study of Silk-Silk Alloy Materials

    NASA Astrophysics Data System (ADS)

    Xue, Ye; Jao, Dave; Hu, Wenbing; Wolf, Nathan; Rocks, Eva-Marie; Hu, Xiao

    Silk fibroin materials can be used for various kinds of biomedical applications. We report a comparative study of silk-silk blend materials using thermal analysis and infrared spectroscopy. Four groups of silk-silk blend films: Mori-Tussah, Mori-Muga, Mori-Eri and Mori-Thai, were fabricated from aqueous solutions and blended at different weight ratios, respectively. These silk-silk blend systems exploit the beneficial material properties of both silks. DSC and temperature-modulated DSC were used to measure the transition temperatures and heat capacity of these water-based silk-silk blend films. Fourier transform infrared spectrometer was used to characterize secondary structures of silk-silk blends. This study demonstrates that Mori silk are fully miscible with Tussah, Muga, Eri and Thai silk at different weight ratios without phase separation. Glass transition temperatures, degradation temperatures and the contents of alpha-helix and random coils of those silk-silk blend films can be controlled by changing the contents of different silks in the blend system. The features of Mori silk combined with the attributes of Tussah, Muga, Eri and Thai silk offer a useful suite of materials for a variety of applications in the future.

  16. Comparative study of analysis methods in biospeckle phenomenon

    NASA Astrophysics Data System (ADS)

    da Silva, Emerson Rodrigo; Muramatsu, Mikiya

    2008-04-01

    In this work we present a review of main statistical properties of speckle patterns and accomplish a comparative study of the more used methods for analysis and extraction of information from optical grainy. The first and second order space-time statistics are dicussed in an overview perspective. The biospeckle phenomenon has detailed attention, specially in its application on monitoring of activity in tissues. The main techniques used to obtain information from speckle patterns are presented, with special prominence to autocorrelation function, co-occurrence matrices, Fujii's method, Briers' contrast and spatial and temporal contrast analisys (LASCA and LASTCA). An incipient method for analysis, based on the study of sucessive correlations contrast, is introduced. Numerical simulations, using diferent probability density functions for velocities of scatterers, were made with two objectives: to test the analysis methods and to give subsidies for interpretation of in vivo results. Vegetable and animal tissues are investigated, achieving the monitoring of senescence process and vascularization maps on leaves, the accompaniment of fungi contamined fruits, the mapping of activity in flowers and the analisys of healing in rats subjected to abdominal surgery. Experiments using the biospeckle phenomenon in microscopy are carried out. At last, it is evaluated the potentiality of biospeckle as diagnosis tool in chronic vein ulcer cared with low intensity laser therapy and the better analysis methods for each kind of tissue are pointed.

  17. Comparative study of different surface decontaminants on chicken quality.

    PubMed

    Sinhamahapatra, M; Biswas, S; Das, A K; Bhattacharyya, D

    2004-10-01

    (1) A comparative study on the effect of different surface decontaminants: hot water at 70 degrees C for one minute; 2% lactic acid for 30 s; 1200 p.p.m. acidified sodium chlorite (ASC) solution for 5 s and 50 p.p.m. chlorine solution for 5 min in the form of dips and sprays on the surface of dressed broilers for 0, 24 and 48 h of storage was conducted. (2) The variables studied were, total plate count (TPC), presumptive coliform count (PCC), pH and extract release volume (ERV). All treatments reduced TPC and PCC. (3) Lactic acid dip and hot water dip were the most effective for reducing TPC (1.36 and 1.28 log/cm2, respectively) with no significant difference between them. (4) ASC and hot water in dip could diminish PCC (1.37 and 1.34 log/cm2, respectively) and did not vary significantly. (5) No treatment affected muscle pH, water holding capacity (WHC), ERV, appearance, smell, tenderness and overall acceptability of treated broilers significantly. (6) Hot water treatment is the cheapest, most convenient and simplest decontamination technique for hygienic and wholesome poultry production.

  18. Rhinosinusal Polyposis and Inverted Papilloma: A Morphometric Comparative Study

    PubMed Central

    Andrade, Gabriel Costa; Fujise, Luciana Harumi; Fernandes, Atílio Maximino; Azoubel, Reinaldo

    2015-01-01

    Introduction Nasal obstruction is one of the main rhinologic complaints, and two diseases must be investigated as differential diagnosis: rhinosinusal polyposis and inverted papilloma. Using traditional methods, the differential diagnosis between these diseases may be difficult. The morphometric study may be a useful tool for differential diagnosis and to define prognosis. Objective Calculate the morphometric values of rhinosinusal polyposis and inverted papilloma and compare the average of variables obtained between the groups. Methods The nasal mucus of 10 patients who had surgery in the Department of Otorhinolaryngology and Surgery of Head and Neck was studied; 5 had rhinosinusal polyposis and 5 had inverted papilloma. After the capture and print of corresponding data of each slide, the largest and smallest diameters of the nuclei were measured and the morphometric variables were calculated: average diameter, perimeter, ratio between largest and smallest diameter, volume, area, ratio of volume to area, form coefficient, contour index, and eccentricity. Results We found a significant difference (p < 0.05) between the two groups in the following morphometric variables: largest diameter, smallest diameter, average diameter, volume, area, perimeter, and ratio of volume to area, indicating that these parameters can be useful in diagnostic differentiation between these diseases. Conclusion We founded morphometric variables higher in patients with inverted papilloma, which can be related to the neoplastic origin of the inverted papilloma. The analysis of nuclear parameters is an instrument of great value in the differential diagnosis between rhinosinusal polyposis and inverted papilloma. PMID:26157491

  19. UV exposure in artificial and natural weathering: A comparative study

    NASA Astrophysics Data System (ADS)

    Heikkilä, A.; Kazadzis, S.; Meinander, O.; Vaskuri, A.; Kärhä, P.; Mylläri, V.; Syrjälä, S.; Koskela, T.

    2017-02-01

    We report on a study focusing on UV exposure conditions in three different types of chambers used for accelerated ageing of materials. The first chamber is equipped with four 300-W UVA/UVB mercury vapour lamps (Ultra-Vitalux/Osram). The second chamber uses four 40-W UVA fluorescent lamps (QUV-340/Q-Lab). The third chamber is Weather-Ometer Ci3000+ from Atlas with a 4500-W xenon arc lamp. UV irradiance prevailing in each chamber was measured using Bentham DM150 double monochromator spectroradiometer. The results were compared to measurements of solar spectral UV irradiance at Jokioinen, Finland, with a Brewer MkIII double monochromator spectrophotometer. The spectral shapes of the exposing UV radiation in the different chambers were found to notably differ from each other and from the solar UV spectrum. Both spatial inhomogeneities and temporal variability caused by various factors, like the ageing of the lamps, were detected. The effects were found to strongly depend on wavelength of the exposing UV radiation. The findings of this study underline the necessity of careful characterization of the UV exposure conditions provided by the facilities used in accelerated testing of materials.

  20. Comparative study of biogenic and abiotic iron-containing materials

    NASA Astrophysics Data System (ADS)

    Cherkezova-Zheleva, Z.; Shopska, M.; Paneva, D.; Kovacheva, D.; Kadinov, G.; Mitov, I.

    2016-12-01

    Series of iron-based biogenic materials prepared by cultivation of Leptothrix group of bacteria in different feeding media ( Sphaerotilus-Leptothrix group of bacteria isolation medium, Adler, Lieske and silicon-iron-glucose-peptone) were studied. Control samples were obtained in the same conditions and procedures but the nutrition media were not infected with bacteria, i.e. they were sterile. Room and low temperature Mössbauer spectroscopy, powder X-ray diffraction (XRD), and infrared spectroscopy (IRS) were used to reveal the composition and physicochemical properties of biomass and respective control samples. Comparative analysis showed differences in their composition and dispersity of present phases. Sample composition included different ratio of nanodimensional iron oxyhydroxide and oxide phases. Relaxation phenomena such as superparamagnetism or collective magnetic excitation behaviour were registered for some of them. The experimental data showed that the biogenic materials were enriched in oxyhydroxides of high dispersion. Catalytic behaviour of a selected biomass and abiotic material were studied in the reaction of CO oxidation. In situ diffuse-reflectance (DR) IRS was used to monitor the phase transformations in the biomass and CO conversion.

  1. Multivariable control of grinding plants: a comparative simulation study.

    PubMed

    Duarte, Manuel; Castillo, Alejandro; Sepúlveda, Florencio; Contreras, Angel; Giménez, Patricio; Castelli, Luis

    2002-01-01

    In this paper five multivariable adaptive and classical control strategies have been studied and implemented in a simulator of the copper grinding plant of CODELCO-Andina. The strategies presented were compared and, according to theory, exhibit good behavior. The extended horizon, pole-placement and model reference multivariable adaptive control strategies were formulated in discrete-time and use a model of the plant whose parameters are updated on line using the recursive least squares method along with UD factorization of the covariance matrix and variable forgetting factor. The direct Nyquist array and sequential loop closing techniques were also studied and simulated. The two-by-two multivariable system chosen to represent the grinding plant has the percentage of solids (density) of the pulp fed to the hydrocyclones (which is highly correlated with the percentage of +65 mesh in the overflow of hydrocyclones) and the sump level as output (controlled) variables. The water flow added to the sump and the speed of the pump are its input (manipulated) variables. All the algorithms tested by simulation exhibited good performance and were able to control the grinding plant in a stable fashion. Adaptive algorithms showed better performance than classical techniques, with the extended horizon and pole-placement algorithms proving to be the best. The fact that adaptive algorithms continuously adjust their parameters renders such controllers superior to those based on fixed parameters.

  2. Breast imaging with ultrasound tomography: a comparative study with MRI

    NASA Astrophysics Data System (ADS)

    Ranger, Bryan; Littrup, Peter; Duric, Neb; Li, Cuiping; Schmidt, Steven; Lupinacci, Jessica; Myc, Lukasz; Szczepanski, Amy; Rama, Olsi; Bey-Knight, Lisa

    2010-03-01

    The purpose of this study was to investigate the performance of an ultrasound tomography (UST) prototype relative to magnetic resonance (MR) for imaging overall breast anatomy and accentuating tumors relative to background tissue. The study was HIPAA compliant, approved by the Institutional Review Board, and performed after obtaining the requisite informed consent. Twenty-three patients were imaged with MR and the UST prototype. T1 weighted images with fat saturation, with and without gadolinium enhancement, were used to examine anatomical structures and tumors, while T2 weighted images were used to identify cysts. The UST scans generated sound speed, attenuation, and reflection images. A qualitative visual comparison of the MRI and UST images was then used to identify anatomical similarities. A more focused approach that involved a comparison of reported masses, lesion volumes, and breast density was used to quantify the findings from the visual assessment. Our acoustic tomography prototype imaged distributions of fibrous stroma, parenchyma, fatty tissues, and lesions in patterns similar to those seen in the MR images. The range of thresholds required to establish tumor volume equivalency between MRI and UST suggested that a universal threshold for isolating masses relative to background tissue is feasible with UST. UST has demonstrated the ability to visualize and characterize breast tissues in a manner comparable to MRI. Thresholding techniques accentuate masses relative to background anatomy, which may prove clinically useful for early cancer detection.

  3. What is the need for comparative effectiveness studies in IBD?

    PubMed

    Flasar, Mark H; Cross, Raymond K

    2014-11-01

    Unlike traditional clinical trial research, Comparative Effectiveness Research seeks to determine what is 'best' for a typical patient when deciding between effective options used in daily practice - a therapy, diagnostic test, or course of action. There is a clear need for Comparative Effectiveness Research in Inflammatory Bowel Disease, a point emphasized by the Institute of Medicine and supported by governmental agencies and escalating funding. This review highlights the rationale and support for Comparative Effectiveness Research, provides examples of Comparative Effectiveness Research in Inflammatory Bowel Disease, and outlines current and future focus for Comparative Effectiveness Research in Inflammatory Bowel Disease.

  4. Comparative Modeling Studies of Boreal Water and Carbon Balance

    NASA Technical Reports Server (NTRS)

    Coughlan, J.; Peterson, David L. (Technical Monitor)

    1997-01-01

    The coordination of the modeling and field efforts for an Intensive Field Campaign (IFC) may resemble the chicken and egg dilemma. This session's theme advocates that early and proactive involvement by modeling teams can produce a scientific and operational benefit for the IFC and Experiment. This talk will provide some examples and suggestions originating from the NASA funded IFC's of the FIFE First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment, Oregon Transect Ecosystem Research (OTTER) and predominately Boreal Ecosystem-Atmosphere Study (BOREAS) Experiments. In February 1994 and prior to the final selection of the BOREAS study sites, a group of funded BOREAS investigators agreed to run their models with data for five community types representing the proposed tower flux sites. All participating models were given identical initial values and boundary conditions and driven with identical climate data. The objectives of the intercomparison exercise were: 1) compare simulation results of participating terrestrial, hydrological, and atmospheric models over selected time frames; 2) learn about model behavior and sensitivity to estimated boreal site and vegetation definitions; 3) prioritize BOREAS field data collection efforts supporting modeling studies; 4) identify individual model deficiencies as early as possible. Out of these objectives evolved some important coordination and science issues for the BOREAS Experiment that can be generalized to IFCs and long term archiving of the data. Some problems are acceptable because they are endemic to maintaining fair and open competition prior to the peer review process. Others are logistical and addressable through application of planning, management, and information sciences. This investigator has identified one source of measurement and model incompatibility that is manifest in the IFC scaling approach. Although intuitively obvious, scaling problems are already more formally defined in

  5. Mesiodistal odontometrics as a distinguishing trait: A comparative preliminary study

    PubMed Central

    Sravya, Taneeru; Dumpala, Rakesh Kumar; Guttikonda, Venkateswara Rao; Manchikatla, Praveen Kumar; Narasimha, Vanajakshi China

    2016-01-01

    Introduction: Sex determination is a vital step in reconstructing an individual profile from unidentified skeletal remnants. Variations in tooth size are influenced by genetic and environmental factors. Tooth size variations have been reported among different populations. Aim: To identify the sex by determining the mesiodistal (MD) dimensions of maxillary canines. Objectives: (1) To compare the MD diameter of all maxillary canines — (a) in the entire urban and tribal population, (b) in urban male and urban female populations, (c) in tribal male and tribal female populations, and (d) in the entire male and female populations and (2) To estimate the percentage of sexual dimorphism individually in urban and tribal populations. Materials and Methods: Fifty subjects each from urban and tribal populations in equal gender ratio were selected in Khammam district, Telangana, for the purpose of this study. After obtaining informed consent, maxillary study models of the selected subjects were made. MD diameters of left and right maxillary canines were measured on casts using vernier calipers. The obtained data were subjected to statistical analysis. Results: (1) The total tribal population showed a greater MD diameter of maxillary canines than the total urban population, (2) Urban males showed a greater MD diameter of maxillary canines than urban females, (3) Tribal males showed a greater MD diameter of maxillary canines than tribal females, (4) The entire male population showed a greater MD diameter of maxillary canines than the entire female population, and (5) The percentage of dimorphism between males and females in individual groups was found to be significant. Conclusion: The study showed maxillary canines exhibiting significant sexual dimorphism and can be used as a distinguishing trait for sex determination along with other procedures. PMID:27555727

  6. Comparative Climate Studies of Earth, Venus and Mars

    NASA Astrophysics Data System (ADS)

    Chassefiere, E.

    2008-12-01

    One of the most promising area in Solar System science is the comparative study of the three terrestrial planets (Venus, Earth, Mars). Why did the three planets evolve in such different ways, from relatively comparable initial states? The small size of Mars, favoring atmospheric escape, certainly played a role in making the present Mars so inhospitable. Venus has almost the same size and density as the Earth, and was probably initially endowed with similar amounts of volatile material. The absence of water in significant amounts on Venus, generally explained by intense primitive atmospheric escape, remains poorly constrained and understood. Two specific problems, related to Mars and Venus climate evolution, will be discussed in this talk. One major challenge of Mars studies is to determine the nature of the present Martian atmosphere: is it the residual of an old atmosphere, progressively lost by escape, or is it young, at steady state equilibrium between outgassing and escape? The possible detection of methane in Martian atmosphere suggests that methane currently is being produced, possibly signing outgassing, since methane is the thermodynamically favoured form of carbon, as released by potential volcanism or hydrothermalism, at low Martian temperature and pressure. Although no typical volcanic gas, like SO2, has ever been detected on Mars, the existence of recent lava flows (a few million years old) shows that a residual volcanism is still episodically active. Another possible tracer of outgassing, that is radon 222, seems promising, and could have been detected (although indirectly) in the Martian atmosphere from recent APXS (MER rovers) and Gamma Ray Spectrometer (Mars- Odyssey) measurements. The lack of any isotopic fractionation of carbon and oxygen in Martian CO2, as shown by existing measurements, suggests that the atmosphere of Mars is young, since it should have been fractionated by escape if it is old. This possibility of a young Martian atmosphere

  7. The evaluation of age-related histomorphometric variables in a cadaver sample of lower socioeconomic status: implications for estimating age at death.

    PubMed

    Keough, N; L'Abbé, E N; Steyn, M

    2009-10-30

    Estimating age at death from adult skeletal remains is a daunting task for human osteologists. For this reason, the evaluation of micro-structural changes in bone with advancing age has become a popular method. However, factors such as nutrition, chronic disease, population group and sex have been suggested to influence the rate of bone turnover, and thus the use of histological methods in providing an accurate age at death has been questioned. The purpose of this study was to evaluate the accuracy and repeatability of 10 histomorphometric traits used to estimate age. The sample comprised of 146 dissection room cadavers of known sex, age and ancestry (105 males and 41 females). A 0.2cmx1.0cm sample was removed from the anterior surface of the mid-shaft of the femur (opposite the linea aspera), and slides were prepared according to standard methodology. The total osteon count (r=0.50), the percentage unremodelled bone (r=-0.50), the total number of non-Haversian canals (r=-0.50) and the average percentage of fragmental bone (r=0.55) had moderate correlations with age, while the total number of measurable osteons (r=0.43), the total number of osteonal fragments (r=0.40), the percentage of fragmentary bone (r=0.37) the average number of lamellae per osteon (r=0.29), the minimum diameter of the Haversian canals (r=0.14) and resorption spaces (r=0.11) had little to no relationship with age. Despite poor correlations with age, eight variables were shown to be highly repeatable (r=0.74-0.93). Moderate to low correlations with age may be attributed to these variables not being related to age in a progressive and predictable fashion, activity patterns or possible chronic disease in the sample. A databank needs to be compiled from larger samples from various populations in order to more holistically assess the relationship between these variables and age as well as other mitigating factors such as disease, nutrition and population group.

  8. Guided bone regeneration via a preformed titanium foil: clinical, histological and histomorphometric outcome of a case series

    PubMed Central

    BASSI, M. ANDREASI; ANDRISANI, C.; LICO, S.; ORMANIER, Z.; OTTRIA, L.; GARGARI, M.

    2016-01-01

    SUMMARY Purpose The aim of this paper was to evaluate the histological and histomorphometric outcome of Preformed Titanium Foil (PTF) to perform Guided Bone Regeneration (GBR) in posterior mandibular atrophies. Materials and methods 10 subjects (1 male; 9 females; mean age 58±11.37 years), with distal mandibular atrophies were selected to perform GBR by means of PTF, using a moldable allograft paste as graft material. The devices, made of a 0,2 mm thick pure titanium foil, were pre-shaped using stereolithographic models obtained from CT-scan of the patients’ recipient site. In the second stage, performed at 6.7±2.33 months, 18 cylindrical two-piece implants were placed and the devices removed, at the same time bone biopsies were harvested. At 4 months, the implants were exposed and submitted to progressive prosthetic load for a span of 4 months. The cases were finalized by means of metal-ceramic cementable restorations. The post finalization follow-up was at 12 months. Results Survival rate (i.e. SVR) was 100% since none fixtures were lost. At the one-year follow up the clinical appearance of the soft tissues was optimal and not pathological signs on probing were recorded. The success rate (i.e. SCR) was 88.2% and the average peri-implant bone reabsorption was 1.17±0.41 mm. The average rate of graft contraction was 19.4±10.55%. The mean percentage occupied by mineralized bone was 48.03±5.93%, while the bone marrow and graft material were 36.1±2.81% and 15.87±4.87 %, respectively. Conclusion The results suggest good potentialities of the method for GBR in distal mandibular atrophies, allowing to maximize the outcome and simplifying the surgical phase. PMID:28042445

  9. Comparative study of ZnO optical dispersion laws

    NASA Astrophysics Data System (ADS)

    Bouzourâa, M.-B.; Battie, Y.; Dalmasso, S.; Zaïbi, M.-A.; Oueslati, M.; Naciri, A. En

    2017-04-01

    We report a comparative study between Forouhi-Bloomer, Tauc-Lorentz and Tanguy dispersion laws for determining the reliable dielectric function of crystallized ZnO. ZnO layers were prepared by sol-gel method and deposited on crystalline silicon (c-Si) by spin coating. Spectroscopic ellipsometry (SE) was performed on ZnO/c-Si and each dispersion law was considered in the physical model for fitting SE experimental data. A best agreement was found between measurements and model. This applies in particular to the Tanguy dispersion. The physical parameters such as excitonic energy, optical gap, damping factor, real and imaginary parts of dielectric function were determined and analyzed. The temperature-dependent photoluminescence spectroscopy (PL) measurements were also used to approve the adequate dispersion law for ZnO material. We found by SE and PL measurements that Tanguy law dispersion can be considered as the most appropriate one for a correct description of ZnO optical dielectric function and for the interpretation of the absorption tail band and for the excitonic band of crystallized ZnO. The band-gap energy, excitonic energy and damping factor parameter are determined and analyzed. Their values (3.37 eV, 48 meV and 39 meV, respectively) extracted from ellipsometry are in good agreement with those obtained by PL measurements.

  10. Liposomes- and ethosomes-associated distamycins: a comparative study.

    PubMed

    Cortesi, Rita; Romagnoli, Romeo; Drechsler, Markus; Menegatti, Enea; Zaid, Abdel N; Ravani, Laura; Esposito, Elisabetta

    2010-12-01

    The present article describes a comparative study of the performances of liposomes and ethosomes as specialized delivery systems for distamycin A (DA) and two of its derivatives. Liposomes and ethosomes were prepared by classical methods, extruded through polycarbonate filters, and characterized in terms of dimensions, morphology, and encapsulation efficiency. It was found that DA was associated with vesicles (either liposomes or ethosomes) by around 16.0%, while both derivatives of DA showed a percentage of association around 80% in the case of liposomes and around 50% in the case of ethosomes. In vitro antiproliferative activity experiments performed on cultured human and mouse leukemic cells demonstrated that vesicles were able to increase the activity of both derivatives of DA. In addition, it was demonstrated that the aging of both liposomes- and ethosomes-associated distamycin suspensions did not heavily influence the vesicle size, while all samples showed a relevant drug leakage with time. Moreover, according to the different physicochemical characteristics of DA and its derivatives (i.e., log P), vesicle-associated DA showed the highest loss of drug with respect to both its derivatives. In conclusion, the enhancement of drug activity expressed by these specialized delivery systems-associated DD could be interesting to obtain an efficient therapeutic effect aimed at reducing or minimizing toxic effects occurring with distamycins administration.

  11. The minds of gods: a comparative study of supernatural agency.

    PubMed

    Purzycki, Benjamin Grant

    2013-10-01

    The present work is the first study to systematically compare the minds of gods by examining some of the intuitive processes that guide how people reason about them. By examining the Christian god and the spirit-masters of the Tyva Republic, it first confirms that the consensus view of the Christian god's mind is one of omniscience with acute concern for interpersonal social behavior (i.e., moral behaviors) and that Tyvan spirit-masters are not as readily attributed with knowledge or concern of moral information. Then, it reports evidence of a moralization bias of gods' minds; American Christians who believe that God is omniscient rate God as more knowledgeable of moral behaviors than nonmoral information. Additionally, Tyvans who do not readily report pro- or antisocial behavior among the things that spirit-masters care about will nevertheless rate spirit-masters' knowledge and concern of moral information higher than nonmoral information. However, this knowledge is distributed spatially; the farther away from spirits' place of governance a moral behavior takes place, the less they know and care about it. Finally, the wider the breadth of knowledge Tyvans attribute to spirit-masters, the more they attribute moral concern for behaviors that transpire beyond their jurisdiction. These results further demonstrate that there is a significant gulf between expressed beliefs and intuitive religious cognition and provides evidence for a moralization bias of gods' minds.

  12. [Comparative EEG study in normal and autistic children].

    PubMed

    Lushchekina, E A; Podreznaia, E D; Lushchekin, V S; Strelets, V B

    2010-01-01

    The work represents the results of a comparative study of spectral power as well as averaged coherence in alpha, beta and gamma EEG bands in 5-to-7-year-old autistic and healthy boys in the state of rest and under cognitive load (mental calculation). The mean age of the examined children was 6 years 4 months. In both healthy and autistic children, there was a clear-cut baseline frontal-occipital gradient of the alpha activity. Performance of the cognitive task led to enhancement of spectral power in the alpha1 band and shifting its maximum to the left hemisphere, did not change the activity in the alpha2 band, and considerably increased the spectral power in the alpha3 band. In healthy children, the spectral power and average coherence of the fast rhythms increased in the central and frontal areas of the left hemisphere. The right-side dominance of the spectral power of the alpha band was revealed in autistic children both in the baseline and during cognitive task. The spectral power of the gamma band was higher in autistic children than in healthy children in the baseline. The cognitive task did not change this fast activity in autistic children.

  13. Comparative study of nail sampling techniques in onychomycosis.

    PubMed

    Shemer, Avner; Davidovici, Batya; Grunwald, Marcelo H; Trau, Henri; Amichai, Boaz

    2009-07-01

    Onychomycosis is a common problem. Obtaining accurate laboratory test results before treatment is important in clinical practice. The purpose of this study was to compare results of curettage and drilling techniques of nail sampling in the diagnosis of onychomycosis, and to establish the best technique and location of sampling. We evaluated 60 patients suffering from distal and lateral subungual onychomycosis and lateral subungual onychomycosis using curettage and vertical and horizontal drilling sampling techniques from three different sites of the infected nail. KOH examination and fungal culture were used for detection and identification of fungal infection. At each sample site, the horizontal drilling technique has a better culture sensitivity than curettage. Trichophyton rubrum was by far the most common pathogen detected by both techniques from all sampling sites. The drilling technique was found to be statistically better than curettage at each site of sampling, furthermore vertical drilling from the proximal part of the affected nail was found to be the best procedure for nail sampling. With each technique we found that the culture sensitivity improved as the location of the sample was more proximal. More types of pathogens were detected in samples taken by both methods from proximal parts of the affected nails.

  14. Osseointegration of alumina bioceramic granules: A comparative experimental study

    NASA Astrophysics Data System (ADS)

    Rerikh, V. V.; Avetisyan, A. R.; Zaydman, A. M.; Anikin, K. A.; Bataev, V. A.; Nikulina, A. A.; Sadovoy, M. A.; Aronov, A. M.; Semantsova, E. S.

    2016-08-01

    To perform a comparative analysis of osseointegration of bioceramic alumina-based granules, hydroxyapatite-based granules, and deproteinized bone granules. The experiment was conducted on 52 adult male Kyoto-Wistar rats weighing 350 to 520 g. The animals were divided into five matched groups that differed only in the type of an implanted material. The granules were implanted in the lumbar vertebral bodies and in the distal right femur of each laboratory animal. Two months after surgery, the animals were euthanized, followed by tissue sampling for morphological studies. An examination of specimens from the groups with implanted alumina granules revealed the newly formed trabecular bone with remodeling signs. The bone tissue filled the intragranular space, tightly adhering to the granule surface. There was no connective tissue capsule on the border between bone tissue and alumina granules. Cylindrical bioceramic alumina-based granules with an open internal channel have a higher strength surpassing than that of analogs and the osseointegration ability close to that of hydroxyapatite and deproteinized bone granules.

  15. Comparative Study Between Wind and Photovoltaic (PV) Systems

    NASA Astrophysics Data System (ADS)

    Taha, Wesam

    This paper reviews two renewable energy systems; wind and photovoltaic (PV) systems. The common debate between the two of them is to conclude which one is better, in terms of cost and efficiency. Therefore, comparative study, in terms of cost and efficiency, is attempted. Regarding total cost of both, wind and PV systems, many parameters must be taken into consideration such as availability of energy (either wind or solar), operation and maintenance, availability of costumers, political influence, and the components used in building the system. The main components and parameters that play major role in determining the overall efficiency of wind systems are the wind turbine generator (WTG), gearbox and control technologies such as power, and speed control. On the other hand, in grid-connected PV systems (GCPVS), converter architecture along with maximum power point tracking (MPPT) algorithm and inverter topologies are the issues that affects the efficiency significantly. Cost and efficiency analyses of both systems have been carried out based on the statistics available till today and would be useful in the progress of renewable energy penetration throughout the world.

  16. Scaling and predictability in stock markets: a comparative study.

    PubMed

    Zhang, Huishu; Wei, Jianrong; Huang, Jiping

    2014-01-01

    Most people who invest in stock markets want to be rich, thus, many technical methods have been created to beat the market. If one knows the predictability of the price series in different markets, it would be easier for him/her to make the technical analysis, at least to some extent. Here we use one of the most basic sold-and-bought trading strategies to establish the profit landscape, and then calculate the parameters to characterize the strength of predictability. According to the analysis of scaling of the profit landscape, we find that the Chinese individual stocks are harder to predict than US ones, and the individual stocks are harder to predict than indexes in both Chinese stock market and US stock market. Since the Chinese (US) stock market is a representative of emerging (developed) markets, our comparative study on the markets of these two countries is of potential value not only for conducting technical analysis, but also for understanding physical mechanisms of different kinds of markets in terms of scaling.

  17. Aging in mouse and human systems: a comparative study.

    PubMed

    Demetrius, Lloyd

    2006-05-01

    This article discusses the significance of mouse models as a basis for elucidating the aging process in humans. We identify certain parallels between mouse and human systems and review the theoretical and empirical support for the claim that the large divergence in the rate of aging between the two species resides in differences in the stability of their metabolic networks. We will show that these differences in metabolic stability have their origin in the different ecological constraints the species experience during their evolutionary history. We exploit these ideas to compare the effect of caloric restriction on murine and human systems. The studies predict that the large increases in mean life span and maximum life-span potential observed in laboratory rodents subject to caloric restriction will not obtain in human populations. We predict that, in view of the different metabolic stability of the two systems, caloric restriction will have no effect on the maximum life-span potential of humans, and a relatively minor effect on the mean life span of nonobese populations. This article thus points to certain intrinsic limitations in the use of mouse models in elucidating the aging process in humans. We furthermore contend the view that these limitations can be mitigated by considering the metabolic stability of the two species.

  18. Spheroid model study comparing the biocompatibility of Biodentine and MTA.

    PubMed

    Pérard, Matthieu; Le Clerc, Justine; Watrin, Tanguy; Meary, Fleur; Pérez, Fabienne; Tricot-Doleux, Sylvie; Pellen-Mussi, Pascal

    2013-06-01

    The primary objective of this study was to assess the biological effects of a new dentine substitute based on Ca₃SiO₅ (Biodentine™) for use in pulp-capping treatment, on pseudo-odontoblastic (MDPC-23) and pulp (Od-21) cells. The secondary objective was to evaluate the effects of Biodentine and mineral trioxide aggregate (MTA) on gene expression in cultured spheroids. We used the acid phosphatase assay to compare the biocompatibility of Biodentine and MTA. Cell differentiation was investigated by RT-qPCR. We investigated the expression of genes involved in odontogenic differentiation (Runx2), matrix secretion (Col1a1, Spp1) and mineralisation (Alp). ANOVA and PLSD tests were used for data analysis. MDPC-23 cells cultured in the presence of MTA had higher levels of viability than those cultured in the presence of Biodentine and control cells on day 7 (P = 0.0065 and P = 0.0126, respectively). For Od-21 cells, proliferation rates on day 7 were significantly lower in the presence of Biodentine or MTA than for control (P < 0.0001). Col1a1 expression levels were slightly lower in cells cultured in the presence of MTA than in those cultured in the presence of Biodentine and in control cells. Biodentine and MTA may modify the proliferation of pulp cell lines. Their effects may fluctuate over time, depending on the cell line considered. The observed similarity between Biodentine and MTA validates the indication for direct pulp-capping claimed by the manufacturers.

  19. A framework for the comparative study of language.

    PubMed

    Uriagereka, Juan; Reggia, James A; Wilkinson, Gerald S

    2013-07-18

    Comparative studies of language are difficult because few language precursors are recognized. In this paper we propose a framework for designing experiments that test for structural and semantic patterns indicative of simple or complex grammars as originally described by Chomsky. We argue that a key issue is whether animals can recognize full recursion, which is the hallmark of context-free grammar. We discuss limitations of recent experiments that have attempted to address this issue, and point out that experiments aimed at detecting patterns that follow a Fibonacci series have advantages over other artificial context-free grammars. We also argue that experiments using complex sequences of behaviors could, in principle, provide evidence for fully recursive thought. Some of these ideas could also be approached using artificial life simulations, which have the potential to reveal the types of evolutionary transitions that could occur over time. Because the framework we propose has specific memory and computational requirements, future experiments could target candidate genes with the goal of revealing the genetic underpinnings of complex cognition.

  20. [Comparative study of different diagnostic methods in pulmonary alveolitis].

    PubMed

    Makhmudova, S Iu

    2009-05-01

    To evaluate and analyze, clinical and roentgenological manifestations of extrinsic allergic alveolitis (EAA) and idiopathic fibrosing alveolitis (IFA) 89 patients underwent bronchoscopy survey and functional test of lungs. Average age of patients was 38,3+/-5,8. Among examined 89 patients 31 (34,8%) patients were poultry farmers, 30 (33,7%) - millers, and 28 (31,5%) - tobacco-growers. EAA was found among 22 poultry farmers, 19 tobacco-growers, and 19 millers. IFA was found among 11 millers, 9 tobacco-growers and 9 poultry farmers. Acute respiratory disease (ARD) was found among 58 patients; 38 patients suffer from lung diseases. Control group consisted of 20 healthy people. Along with general blood analysis, all patients underwent - roentgenological analysis of thorax in two shifts. Recent studies show that CT lung screening is more sensitive than standard lung screening methods in detecting lung disease. Comparative analysis allowed concluding that Real-Time CT method is the most effective. CT lung screening is more sensitive than standard lung screening methods in detecting lung diseases.

  1. Fungal biodegradation of anthracene-polluted cork: A comparative study.

    PubMed

    Jové, Patrícia; Olivella, Maria À; Camarero, Susana; Caixach, Josep; Planas, Carles; Cano, Laura; De Las Heras, Francesc X

    2016-01-01

    The efficiency of cork waste in adsorbing aqueous polycyclic aromatic hydrocarbons (PAHs) has been previously reported. Biodegradation of contaminated cork using filamentous fungi could be a good alternative for detoxifying cork to facilitate its final processing. For this purpose, the degradation efficiency of anthracene by three ligninolytic white-rot fungi (Phanerochaete chrysosporium, Irpex lacteus and Pleurotus ostreatus) and three non-ligninolytic fungi which are found in the cork itself (Aspergillus niger, Penicillium simplicissimum and Mucor racemosus) are compared. Anthracene degradation by all fungi was examined in solid-phase cultures after 0, 16, 30 and 61 days. The degradation products of anthracene by P. simplicissimum and I. lacteus were also identified by GC-MS and a metabolic pathway was proposed for P. simplicissimum. Results show that all the fungi tested degraded anthracene. After 61 days of incubation, approximately 86%, 40%, and 38% of the initial concentration of anthracene (i.e., 100 µM) was degraded by P. simplicissimum, P. chrysosporium and I. lacteus, respectively. The rest of the fungi degraded anthracene to a lesser extent (<30%). As a final remark, the results obtained in this study indicate that P. simplicissimum, a non-ligninolytic fungi characteristic of cork itself, could be used as an efficient degrader of PAH-contaminated cork.

  2. A comparative study of prebiotic and present day translational models

    NASA Technical Reports Server (NTRS)

    Rein, R.; Raghunathan, G.; Mcdonald, J.; Shibata, M.; Srinivasan, S.

    1986-01-01

    It is generally recognized that the understanding of the molecular basis of primitive translation is a fundamental step in developing a theory of the origin of life. However, even in modern molecular biology, the mechanism for the decoding of messenger RNA triplet codons into an amino acid sequence of a protein on the ribosome is understood incompletely. Most of the proposed models for prebiotic translation lack, not only experimental support, but also a careful theoretical scrutiny of their compatibility with well understood stereochemical and energetic principles of nucleic acid structure, molecular recognition principles, and the chemistry of peptide bond formation. Present studies are concerned with comparative structural modelling and mechanistic simulation of the decoding apparatus ranging from those proposed for prebiotic conditions to the ones involved in modern biology. Any primitive decoding machinery based on nucleic acids and proteins, and most likely the modern day system, has to satisfy certain geometrical constraints. The charged amino acyl and the peptidyl termini of successive adaptors have to be adjacent in space in order to satisfy the stereochemical requirements for amide bond formation. Simultaneously, the same adaptors have to recognize successive codons on the messenger. This translational complex has to be realized by components that obey nucleic acid conformational principles, stabilities, and specificities. This generalized condition greatly restricts the number of acceptable adaptor structures.

  3. A comparative study of input devices for digital slide navigation.

    PubMed

    Molin, Jesper; Lundström, Claes; Fjeld, Morten

    2015-01-01

    This paper describes work presented at the Nordic Symposium on Digital Pathology 2014, Linköping, Sweden. Quick and seamless integration between input devices and the navigation of digital slides remains a key barrier for many pathologists to "go digital." To better understand this integration, three different input device implementations were compared in terms of time to diagnose, perceived workload and users' preferences. Six pathologists reviewed in total nine cases with a computer mouse, a 6 degrees-of-freedom (6DOF) navigator and a touchpad. The participants perceived significantly less workload (P < 0.05) with the computer mouse and the 6DOF navigator, than with the touchpad, while no effect of the input device used on the time to diagnose was observed. Five out of six pathologists preferred the 6DOF navigator, while the touchpad was the least preferred device. While digital slide navigation is often designed to mimic microscope interaction, the results of this study demonstrate that in order to minimize workload there is reason to let the digital interaction move beyond the familiar microscope tradition.

  4. Comparative study of crude and purified cellulose from wheat straw.

    PubMed

    Sun, Xiao-Feng; Sun, Run-Cang; Su, Yinquan; Sun, Jing-Xia

    2004-02-25

    A sequential totally chlorine-free procedure for isolation of cellulose from wheat straw was proposed in this study. The dewaxed straw was pretreated with 0.5 M NaOH in 60% methanol at 60 degrees C for 2.5 h under ultrasonic irradiation for 0-35 min and sequentially posttreated with 2% H(2)O(2)-0.2% TAED at pH 11.8 for 12 h at 48 degrees C, which together solubilized 85.3-86.1% of the original hemicelluloses and 91.7-93.2% of the original lignin, respectively. The yield of crude cellulose ranged between 46.2 and 49.2% on a dry weight basis related to wheat straw, which contained 11.2-12.2% residual hemicelluloses and 2.5-2.9% remaining lignin. Further treatment of the corresponding crude cellulosic preparations with 80% acetic acid-70% nitric acid under the condition given yielded 36.8-37.7% of the purified cellulose, which contained minor amounts of bound hemicelluloses (2.5-2.8%) and was relatively free of associated lignin (0.1-0.2%). The isolated crude and purified cellulose samples were comparatively studied by FT-IR and CP/MAS (13)C NMR spectroscopy, and the relative crystallinity was also estimated. The final stage treatment with 80% acetic acid-70% nitric acid decreased the hemicelluloses and lignin associated in the crude cellulose but led to 3.1-5.4% degradation of the original cellulose; in addition, the purity of the obtained cellulose was high. However, it was found that the final stage treatment is not severe enough to cause decrystallization of cellulose. The thermal stability of the purified cellulose is higher than that of the corresponding crude cellulose.

  5. Comparative hemolysis study of clinically available centrifugal pumps.

    PubMed

    Naito, K; Suenaga, E; Cao, Z L; Suda, H; Ueno, T; Natsuaki, M; Itoh, T

    1996-06-01

    Centrifugal pumps have become important devices for cardiopulmonary bypass and circulatory assistance. Five types of centrifugal pumps are clinically available in Japan. To evaluate the blood trauma caused by centrifugal pumps, a comparative hemolysis study was performed under identical conditions. In vitro hemolysis test circuits were constructed to operate the BioMedicus BP-80 (Medtronic, BioMedicus), Sarns Delphin (Sarns/3M Healthcare), Isoflow (St. Jude Medical [SJM]), HPM-15 (Nikkiso), and Capiox CX-SP45 (Terumo). The hemolysis test loop consisted of two 1.5 m lengths of polyvinyl chloride tubing with a 3/8-inch internal diameter, a reservoir with a sampling port, and a pump head. All pumps were set to flow at 6 L/min against the total pressure head of 120 mm Hg. Experiments were conducted simultaneously for 6 h at room temperature (21 degrees C) with fresh bovine blood. Blood samples for plasma-free hemoglobin testing were taken, and the change in temperature at the pump outlet port was measured during the experiment. The mean pump rotational speeds were 1,570, 1,374, 1,438, 1,944, and 1,296 rpm, and the normalized indexes of hemolysis were 0.00070, 0.00745, 0.00096, 0.00066, 0.00090 g/100 L for the BP-80, Sarns, SJM, Nikkiso, and Terumo pumps, respectively. The change in temperature at the pump outlet port was the least for the Nikkiso pump (1.8 degrees C) and the most with the SJM pump (3.8 degrees C). This study showed that there is no relationship between the pump rotational speed (rpm) and the normalized index of hemolysis in 5 types of centrifugal pumps. The pump design and number of impellers could be more notable factors in blood damage.

  6. Comparative EEG mapping studies in Huntington's disease patients and controls.

    PubMed

    Painold, Annamaria; Anderer, Peter; Holl, Anna K; Letmaier, Martin; Saletu-Zyhlarz, Gerda M; Saletu, Bernd; Bonelli, Raphael M

    2010-11-01

    Huntington's disease (HD) is a devastating neurodegenerative disorder with prominent motor and cognitive decline. Previous studies with small sample sizes and methodological limitations have described abnormal electroencephalograms (EEG) in this cohort. The aim of the present study was to investigate objectively and quantitatively the neurophysiological basis of the disease in HD patients as compared to normal controls, utilizing EEG mapping. In 55 HD patients and 55 healthy controls, a 3-min vigilance-controlled EEG (V-EEG) was recorded during midmorning hours. Evaluation of 36 EEG variables was carried out by spectral analysis and visualized by EEG mapping techniques. To elucidate drug interference, the analysis was performed for the total group, unmedicated patients only and between treated and untreated patients. Statistical overall analysis by the omnibus significance test demonstrated significant (p < 0.01 and p < 0.05) EEG differences between HD patients and controls. Subsequent univariate analysis revealed a general decrease in total power and absolute alpha and beta power, an increase in delta/theta power, and a slowing of the centroids of delta/theta, beta and total power. The slowing of the EEG in HD reflects a disturbed brain function in the sense of a vigilance decrement, electrophysiologically characterized by inhibited cortical areas (increased delta/theta power) and a lack of normal routine and excitatory activity (decreased alpha and beta power). The results are similar to those found in other dementing disorders. Medication did not affect the overall interpretation of the quantitative EEG analysis, but certain differences might be due to drug interaction, predominantly with antipsychotics. Spearman rank correlations revealed significant correlations between EEG mapping and cognitive and motor impairment in HD patients.

  7. Comparative analysis of collagen membranes for the treatment of implant dehiscence defects.

    PubMed

    Oh, Tae-Ju; Meraw, Stephen J; Lee, Eun-Ju; Giannobile, William V; Wang, Hom-Lay

    2003-02-01

    Guided bone regeneration (GBR) evolved from the concept of guided tissue regeneration (GTR) and has been used for reconstructing sites with bone deficiencies associated with dental implants. For GBR, the use of absorbable collagen membranes has been increasing, but, at present, scientific information on the use of collagen membranes for GBR is limited. This study was aimed to clinically and histomorphometrically compare two collagen membranes, Bio-Gide(R) and BioMend ExtendTM, for the treatment of implant dehiscence defects in eight mongrel dogs. Implant dehiscence defects were surgically created in edentulous ridges, followed by the placement of three endosseous implants bilaterally in the mandible. Each implant dehiscence defect was randomly assigned to one of three treatment groups: (1) control (no membrane), (2) porcine dermis collagen barrier (Bio-Gide) or (3) bovine tendon collagen barrier (BioMend Extend). Dogs were sacrificed at 4 and 16 weeks (four dogs each) after treatment. Histomorphometric analysis included percentage linear bone fill (LF), new bone-to-implant contact (BIC) and area of new bone fill (BF). The results of the study revealed no significant differences among groups for any parameter at 4 weeks. However, at 16 weeks, more LF, BIC, and BF were noted in the membrane-treated groups than controls. BioMend Extend-treated defects demonstrated significantly greater BIC than control (P < 0.05) at this time point. BIC at 16 weeks was significantly greater than 4-week BIC (P < 0.05). Membrane exposure occurred in 9 out of 15 sites examined, resulting in significantly less LF and BIC than the sites without membrane exposure (P < 0.05). The results of this study indicate that: (1) GBR treatment with collagen membranes may significantly enhance bone regeneration, manifested at late stage (16 weeks) of healing; and (2) space maintenance and membrane coverage were the two most important factors affecting GBR using bioabsorbable collagen membranes.

  8. Comparative Case Study of Two Biomedical Research Collaboratories

    PubMed Central

    Teasley, Stephanie D; Bhatnagar, Rishi

    2005-01-01

    Background Working together efficiently and effectively presents a significant challenge in large-scale, complex, interdisciplinary research projects. Collaboratories are a nascent method to help meet this challenge. However, formal collaboratories in biomedical research centers are the exception rather than the rule. Objective The main purpose of this paper is to compare and describe two collaboratories that used off-the-shelf tools and relatively modest resources to support the scientific activity of two biomedical research centers. The two centers were the Great Lakes Regional Center for AIDS Research (HIV/AIDS Center) and the New York University Oral Cancer Research for Adolescent and Adult Health Promotion Center (Oral Cancer Center). Methods In each collaboratory, we used semistructured interviews, surveys, and contextual inquiry to assess user needs and define the technology requirements. We evaluated and selected commercial software applications by comparing their feature sets with requirements and then pilot-testing the applications. Local and remote support staff cooperated in the implementation and end user training for the collaborative tools. Collaboratory staff evaluated each implementation by analyzing utilization data, administering user surveys, and functioning as participant observers. Results The HIV/AIDS Center primarily required real-time interaction for developing projects and attracting new participants to the center; the Oral Cancer Center, on the other hand, mainly needed tools to support distributed and asynchronous work in small research groups. The HIV/AIDS Center’s collaboratory included a center-wide website that also served as the launch point for collaboratory applications, such as NetMeeting, Timbuktu Conference, PlaceWare Auditorium, and iVisit. The collaboratory of the Oral Cancer Center used Groove and Genesys Web conferencing. The HIV/AIDS Center was successful in attracting new scientists to HIV/AIDS research, and members

  9. [Comparative studies of methods of salmonella enrichment (author's transl)].

    PubMed

    Pietzsch, O; Kretschmer, F J; Bulling, E

    1975-07-01

    Eight different methods of salmonella enrichment were compared in two series of experiments involving 100 samples of whole-egg powder and 80 samples of frozen whole liquid egg, respectively. 66 out of a total of 100 samples of whole-egg powder had been artificially infected with varying numbers of S. typhi-murium; 60 out of 80 samples of frozen whole liquid egg were found to be naturally infected with various salmonella species. 3 of the 8 methods (Table 1) were compared within an international collaborative study with 14 laboratories in 11 countries participating. A reduction of the pre-enrichment period from 18 to 6 hours and of volumes used in pre-enrichment and selective enrichment from 10 and 100 ml, respectively to 1 and 10 ml, respectively were found to have adverse influence upon the result of isolations, in particular in the case of weakly infected samples. In contrast, extended incubation over 48 hours as well as preparation of two sub-cultures on solid selective media following incubation of enrichment cultures over 18-24 hours and 42-48 hours, respectively always resulted in a certain increase of salmonella yield which, however, exhibited gradual differences for the individual methods examined. Preparation of a 2nd sub-culture meant, in particular, a decisive improvement of the result of isolations from artificially infected samples if selenite-cystine enrichment volumes were 10 and 100 ml, respectively. The best results could be obtained by means of the following methods of enrichment: Pre-enrichment of material in buffered peptone water at 37 degrees C over 18 hours; pipetting of 10 ml inoculated and incubated pre-enriched material into 100 ml selenite-cystine or tetrathionate enrichment medium according to MULLER-KAUFFMANN; onward incubation of the enrichment culture at 43 degrees C over 48 hours; and preparation of sub-cultures on solid selective media after 24 and 48 hours. The method using tetrathionate enrichment medium was found to be most

  10. Five-Year-Olds' Fascination for Television: A Comparative Study.

    ERIC Educational Resources Information Center

    Hake, Karin

    2001-01-01

    Compared 5-year-olds' understanding of and fascination with a public service and a commercial television program; also compared parents' and children's perspectives. Found that children were particularly fascinated by sequences containing conflicts and aggression. Sixteen of 20 children chose the commercial channel program. Parents showed insight…

  11. Comparative study on dynamics associated with terrestrial and Jovian substorms

    NASA Astrophysics Data System (ADS)

    Ge, Yasong

    Terrestrial substorms have been studied for over four decades and our understanding about this phenomenon has improved through those studies. However, many issues regarding substorms are still controversial, especially the initiation mechanism of substorm onset. To understand the initiation mechanism, we have to first answer some important questions. What is the substorm expansion onset? What is the physics behind its phenomenological definition? Where does the initiation start? What is the relation of tail reconnection with near-Earth onsets? Where does tail reconnection occur? While one way to understand better the physics of substorms is to increase the number of spacecraft and the resolution of ground observations, another way is to compare substorm phenomena between different planets. In this study, we investigate the different phases of substorms both on the Earth and Jupiter. For Jovian dynamic event, we need to know if they are substorms? How are they driven? How can we better understand terrestrial substorms through studying Jovian substorms? We used Polar, GOES, Cluster and ground-station observations to study terrestrial substorms and used the Galileo observations to study Jovian dynamic events. A 3-day growth phase of Jovian substorm is discovered, which is also found driven by the internal processes including mass-loading at Io instead of the solar wind. This discovery establishes the substorm nature of those dynamics events which have counterparts of key elements of terrestrial substorms, including the connection of those events with the Jupiter's polar auroral activity. Near-planet dipolarization caused by the mid-tail reconnection is also investigated. In the near-Earth tail region, dipolarizations appear to be associated with mid-tail reconnections, near-tail flow braking and formation of substorm current wedge. In both magnetospheres, major onsets of substorms are found to be due to the major tail reconnection which can globally release the loaded

  12. Comparative study of novel endovascular treatment techniques for intracranial aneurysms

    NASA Astrophysics Data System (ADS)

    Cantón, Gádor; Lasheras, Juan C.; Levy, David I.; Sparks, Steven R.

    2002-11-01

    Intracranial aneurysms are life-threatening vascular lesions, which are potentially treatable to avoid the consequences of their rupture. Current treatments, either surgical or endovascular, are all guided to reduce the hemodynamic forces acting on the aneurysm wall in an effort to minimize the risk of rupture. Surgical clipping is still the most used technique to treat this type of aneurysm but there is a continued demand for less invasive approaches. This has led to the development of several endovascular techniques. We report here a comparative study of the reduction in the hemodynamic stresses and the modification of the flow in the parent vessel resulting from the use of three different techniques. The first one consists of endosaccular packing with platinum coils (GDC, Target Therapeutics), which is already widely used but its long-term efficacy has not yet been determined. The second one consists of the embolization of the aneurismal sac with Onyx, a polymer which hardens when in contact with the blood (being developed by Micro Therapeutics, Inc.). The third one involves the packing of the sac with hydrocoils, platinum wires coated with a gel which quickly hydrates when in contact with blood (developed by MicroVention). A Digital Particle Image Velocimetry (DPIV) system is used to measure in vitro the velocity field inside a model of an ACOM aneurysm (an aneurysm forming in the anterior communicating artery). Physiological accurate pulsatile flow conditions are input to the arterial model through a programmable pump. The measurements show that although all treatment techniques lead to a reduction in both normal and tangential shear stresses on the aneurismal sac, each one of them also leads to different modifications of the flow in the parent vessel which may have consequences related to potential for clotting. Comparison of the untreated aneurysm with the above three treated cases also showed that the characteristics of the wall shear stresses on the parent

  13. Does interprofessional simulation increase self-efficacy: a comparative study

    PubMed Central

    Watters, Colm; Reedy, Gabriel; Ross, Alastair; Morgan, Nicola J; Handslip, Rhodri; Jaye, Peter

    2015-01-01

    Objectives In this work, we have compared uniprofessional and interprofessional versions of a simulation education intervention, in an attempt to understand more about whether it improves trainees’ self-efficacy. Background Interprofessionalism has been climbing the healthcare agenda for over 50 years. Simulation education attempts to create an environment for healthcare professionals to learn, without potential safety risks for patients. Integrating simulation and interprofessional education can provide benefits to individual learners. Setting The intervention took place in a high-fidelity simulation facility located on the campus of a large urban hospital. The centre provides educational activities for an Academic Health Sciences Centre. Approximately 2500 staff are trained at the centre each year. Participants One hundred and fifteen nurses and midwives along with 156 doctors, all within the early years of their postgraduate experience participated. All were included on the basis of their ongoing postgraduate education. Methods Each course was a one-day simulation course incorporating five clinical and one communication scenarios. After each a facilitated debriefing took place. A mixed methods approach utilised precourse and postcourse questionnaires measuring self-efficacy in managing emergency situations, communication, teamwork and leadership. Results Thematic analysis of qualitative data showed improvements in communication/teamwork and leadership, for doctors and nurses undergoing simulation training. These findings were confirmed by statistical analysis showing that confidence ratings improved in nurses and doctors overall (p<0.001). Improved outcomes from baseline were observed for interprofessional versus uniprofessional trained nurses (n=115; p<0.001). Postcourse ratings for doctors showed that interprofessional training was significantly associated with better final outcomes for a communication/teamwork dimension (n=156; p<0.05). Conclusions This

  14. Impact comparative study of phone carcasses behavior by FEM

    NASA Astrophysics Data System (ADS)

    Constantin, Cărăuşu; Plăvănescu, Simona; Dumitru, Nedelcu

    2015-07-01

    A constant concern of scientific research is based on plastics replace with biodegradable materials that reduce the adverse impact of waste on the environment. A biodegradable material that arouses interest lately is Arboform which is made of lignin, a component of wood and woody plants. Replacing plastic with Arboform in carrying components of products requires technical and economic studies on the implications of such replacement. Numerical simulation methods are a fast and economical way of analyzing the behavior of a product in various mechanical, thermal, electromagnetic and so on. The paper presents comparative results of numerical simulation using the software package SolidWorks impact behavior through the “Drop Test” of half shells made of High Density Polyethylene (HDPE) and of the Arboform LV3 Nature. Simulation watched the half-carcass behavior in three cases of accidental impact, “head”, “corner” and the “back side”. We analyzed the size and location of the maximum voltage and maximum deformation resulting from impact. Simulations have shown for all three cases a maximum voltage increase when using Arboform to use PEDH 93% for impact “forward” and “corner” and only 48.77% “back side” impact. If the maximum displacement, it increasing from carcasses of Arboform 4% for impact “head” and 6% for impact “corner”, but fell by 2.7% for the “back side” impact. The significant increase of stress can be attributed to the higher density of Arboform to PEDH, which led to different weights of the two half-carcasses.

  15. A Comparative Study of Shaping Ability of four Rotary Systems

    PubMed Central

    Zarzosa, José Ignacio; Pallarés, Antonio

    2015-01-01

    Purpose This study compared the cutting area, instrumentation time, root canal anatomy preservation and non-instrumented areas obtained by F360®, Mtwo®, RaCe® and Hyflex® files with ISO size 35. Material and Methods 120 teeth with a single straight root and root canal were divided into 4 groups. Working length was calculated by using X-rays. The teeth were sectioned with a handpiece and a diamond disc, and the sections were observed with Nikon SMZ-2T stereoscopic microscope and an Intralux 4000-1 light source. The groups were adjusted with a preoperative analysis with AutoCAD. The teeth were reconstructed by a #10 K-File and epoxy glue. Each group was instrumented with one of the four file systems. The instrumentation time was calculated with a 1/100 second chronometer. The area of the thirds and root canal anatomy preservation were analyzed with AutoCAD 2013 and the non-instrumented areas with AutoCAD 2013 and SMZ-2T stereoscopic microscope. The statistical analysis was made with Levene’s Test, ANOVA, Bonferroni Test and Pearson´s Chi-square. Results Equal variances were shown by Levene’s Test (P > 0.05). ANOVA (P > 0.05) showed the absence of significant differences. There were significant differences in the instrumentation time (P < 0.05). For root canal anatomy preservation and non-instrumented areas, there were no significant differences between all systems (P > 0.05). Conclusions The 4 different rotary systems produced similar cutting area, root canal anatomy preservation and non-instrumented areas. Regarding instrumentation time, F360® was the fastest system statistically. PMID:27688412

  16. A comparative study of bovine and ovine Haemophilus somnus isolates.

    PubMed Central

    Ward, A C; Jaworski, M D; Eddow, J M; Corbeil, L B

    1995-01-01

    Bacterial isolates (including 17 Haemophilus somnus isolates and an H. somnus-like isolate) from asymptomatic or diseased cattle and sheep, were evaluated for markers associated with virulence and host predilection. The isolates were separated into 6 distinct biovariants, 3 for sheep and 3 for cattle, based on reactions in a battery of 21 test media. Three bovine isolates associated with disease caused hemolysis of bovine blood. The rest of the isolates did not hemolyze either bovine or ovine erythrocytes. Protein profiles of all H. somnus isolates were similar with the exception of the major outer membrane proteins (MOMPs). The MOMPs of isolates associated with disease in cattle had a relative molecular weight of approximately 41 kDa compared with 33 kDa for the MOMPs of isolates from asymptomatic cattle. The MOMPs from sheep isolates were either slightly higher or lower than the 41 kDa MOMPs of bovine isolates. Major antigens detected by Western blotting were similar in all isolates except the H. somnus-like isolate. An immunodominant 40 kDa antigen was conserved in all H. somnus isolates. Antibodies to this antigen have previously been found to be protective in cattle and may also be protective for sheep. Marked differences between cattle and sheep isolates were revealed by use of restriction enzyme analysis, which separated the isolates into 12 ribotypes and 15 unique DNA profiles. Thus, cattle and sheep isolates in this collection had distinctive differences in biochemical reactions, MOMP profiles, and DNA analyses. Such differences have potential value for epidemiological studies and may also be used to evaluate host specificity of H. somnus isolates. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. PMID:8521348

  17. Comparative study of Mycobacterium bovis primary isolation methods.

    PubMed

    de Azevedo Issa, Marina; Martins Soares Filho, Paulo; Fonseca Júnior, Antônio Augusto; Arrais Hodon, Mikael; Cristian Dos Santos, Lílian; Karlisson Pimenta Dos Reis, Jenner; Cerqueira Leite, Rômulo

    For the definitive diagnosis of bovine tuberculosis, isolation of the etiologic agent is required. However, there is no consensus on the best methodology for isolation of Mycobacterium bovis in Brazil. This study evaluated the most used decontaminants and culture media in the country, in order to identify the best combination for the Brazilian samples. Three decontaminants - 2% sodium hydroxide (w/v), 0.75% hexadecylpiridinium chloride (w/v) and 5% sulphuric acid (v/v) and four culture media - 7H11 Middlebrook with additives and OADC supplement "A" (7H11 A), the same media with another supplement trademark (7H11 B), tuberculosis blood agar (B83) and Stonebrink's medium were compared. Regarding the isolation, there were no significant differences between the decontaminants and media combinations, except 7H11A combined to any decontaminant. However, the mean colonies score was significantly greater when the samples were decontaminated with 5% sulphuric acid and inoculated in 7H11 B or SB, without significant difference between them, although colonies appeared earlier on 7H11B than on SB. The trademark of OADC supplement influenced the isolation rate and the number of isolated colonies in Middlebrook 7H11. An incubation time of four weeks was required to detect all positive samples in 7H11 B after decontamination with 5% sulphuric acid but there was an increase in the number of colonies until the sixth week of incubation. Overall, the best strategy for the primary isolation of M. bovis from Brazilian samples was the decontamination with 5% sulphuric acid (final concentration) and inoculation in Middlebrook 7H11 medium formulated with OADC supplement "B".

  18. Comparative study of optical fiber cure-monitoring methods

    NASA Astrophysics Data System (ADS)

    Crosby, Peter A.; Powell, Graham R.; Fernando, Gerard F.; Waters, David N.; France, Chris M.; Spooncer, Ronald C.

    1997-06-01

    This paper reports on a comparative study undertaken for different types of optical fiber sensor developed to monitor the cure of an epoxy resin system. The optical fiber sensors used to monitor the cure process were based on transmission spectroscopy, evanescent wave spectroscopy and refractive index monitoring. The transmission sensor was prepared by aligning two optical fibers within a specially prepared sleeve with a gap between the optical fiber end-faces. During cure, resin from the specimen flowed into the gap between the optical fibers allowing transmission spectra of the resin to be obtained. The evanescent wave sensor was prepared by stripping the cladding from a high refractive index core optical fiber. The prepared sensor was embedded in the sample and attenuated total reflectance spectra recorded from the resin/core boundary. Refractive index monitoring was undertaken using a high refractive index core optical fiber which had a small portion of its cladding removed. The prepared sensor was embedded in the resin specimen and light from a single wavelength source was launched into the fiber. Changes in the guiding characteristics of the sensor due to refractive index changes at the resin/core boundary were used to monitor the progress of the cure reaction. The transmission and evanescent wave spectroscopy sensors were used to follow changes in characteristic near-infrared absorption bands of the resin over the range 1450 - 1700 nm during the cure reaction. Consequently these techniques required tunable wavelength sources covering specific wavelength ranges. However, the refractive index based sensor used a single wavelength source. Therefore the equipment costs for this type of sensor were considerably less. Additionally, the refractive index sensor did not require a single wavelength source at any particular wavelength and could be applied to any spectral region in which the optical fiber would transmit light. The advantages and disadvantages of these

  19. Comparative in vitro efficacy of antimicrobial shampoos: a pilot study.

    PubMed

    Young, Rebecca; Buckley, Laura; McEwan, Neil; Nuttall, Tim

    2012-02-01

    This study compared the antimicrobial efficacy of shampoos against meticillin-sensitive Staphylococcus pseudintermedius (MSSP), meticillin-resistant S. pseudintermedius (MRSP), antibiotic-sensitive Pseudomonas aeruginosa (PA), multidrug-resistant P. aeruginosa (MDR-PA) and Malassezia pachydermatis. Three isolates were incubated for 10, 30 and 60 min with each shampoo diluted in phosphate-buffered saline. Aliquots were then incubated for 16-18 h on sheep blood agar (bacteria) or for 3 days on Sabouraud's dextrose agar (Malassezia). The minimal bactericidal concentrations (MBCs) for chlorhexidine products (Malaseb(®), Pyoderm(®)/Microbex(®) and Hibiscrub(®)) were 1:1,024-1:2,048 for MSSP and MRSP, 1:512-1:1,024 for PA and MDR-PA, and 1:2,048-1:5,096 for Malassezia at all time points. The MBCs for benzoyl peroxide (Paxcutol(®)) for MSSP and MRSP were 1:2-1:8 at 10 min, and 1:256 after 30 and 60 min. A 1:2 dilution was effective against Pseudomonas, and 1:512-1:1,024 dilutions were effective against Malassezia at all time points. The MBCs for ethyl lactate (Etiderm(®)) for MSSP and MRSP were 1:2 at 10 min, and 1:2-1:16 after 30 and 60 min. A 1:2 dilution was effective against Pseudomonas, and a 1:512 dilution was effective against Malassezia at all time points. Chloroxylenol (Coatex(®)) and acetic acid-boric acid (Malacetic(®)) were not effective against MSSP, MRSP or Pseudomonas. Both were effective against Malassezia at 1:8-1:16 dilution at 10 min, and at 1:8-1:32 dilution after 30 and 60 min. In conclusion, chlorhexidine appeared to be the most effective topical biocide, and MRSP and MDR-PA were no less susceptible than antibiotic-sensitive organisms. These results should, however, be confirmed with larger numbers of isolates.

  20. Comparative studies of methods of obtaining AGW's propagation properties

    NASA Astrophysics Data System (ADS)

    Lue, H. Y.; Kuo, F. S.

    2012-03-01

    Three among the existing methods of obtaining the properties (intrinsic period, wavelength, propagation direction) of atmospheric gravity waves (AGWs) were compared and studied by numerical method to simulate radar data. Three-dimensional fluctuation velocity satisfying dispersion equation and polarization relation of atmospheric gravity wave were generated, then the numerical data were analysed by these methods to obtain the properties of waves. We found that, hodograph analysis was accurate for a monochromatic wave in obtaining its wave period and propagation direction, but the analysis became erratic for the case of multiple waves' superposition. The error was especially large when data consisted of both upward propagating waves and downward propagating waves. The hodograph method became meaningful again if all the component waves propagated in the same direction and the resulting period was dominantly decided by the lowest frequency wave. Stokes parameters method would obtain statistically meaningful values of wave period and azimuth if the spreading of the azimuths among the component waves did not exceed 90° and the resulting period and azimuth were dominated by the lowest frequency wave component as well, irrespective of the vertical sense of propagation. Another method called phase and group velocity tracing technique was reconfirmed to be meaningful in measuring the characteristic wave period and vertical group and phase velocities of a wave packet: the characteristic wave period and vertical wavelength was dominated by the wave with the highest frequency among the component waves in the wave packet. Based on these numerical results, a composite procedure of data analysis for wave propagation was proposed and an example of real data analysis was presented.

  1. Comparative studies and healthcare policy: learning and mislearning across borders.

    PubMed

    Okma, Kieke G H; Marmor, Theodore R

    2013-10-01

    This article addresses the vocabulary of cross-national analysis and commentary about health care, health policy and health politics. We conclude there is a large gap between promise and performance in comparative policy commentary and point to major sources of confusion, such as the lack of generally agreed vocabulary, vague language and the use of faddish and misleading terms and aspirational labels (illustrated by a selection of widely used expressions in comparative reports). We next examine the basic purposes of international policy comparison, distinguish three useful and two misleading approaches and frame defensible ground rules for comparative work.

  2. Asthmatic children away from home: a comparative psychological study.

    PubMed

    Bentley, J

    1975-09-01

    The essential difference that emerged from a comparison of the fantasies of Rapidly Remitting and Nonremitting asthmatic children was found to be in the area of emotional awareness. The children who lost their asthmatic symptoms when separated from home were found to have some awareness of angry feelings toward parental figures whom they experienced as hostile and/or rejecting. They were also found to be aware, to some extent, of longings for a relationship with a person who would provide nurturing care or guidance. The Nonremitting children, on the other hand, were found to be lacking in any awareness of either angry feelings or longings for a nurturing relationship. A study of the test materials of both groups of children reveals that these feelings are present in all eight children. Yet they have been totally repressed in the Nonremitting children, while the Rapidly Remitting children have, apparently, not felt the need to resort to such massive repression. Thus a second area of difference, implied in the first, emerges when we compare these two groups of children in terms of defensive ego functioning. Abramson's emphasis on the central importance of the period in which the child's emotional conflict arose proved to be valid for this study. He predicted that those children whose asthma begins at or near the period of toilet training will be the same ones who will have most difficulty giving up their asthmatic symptoms. Although I have not been able to validate dates for onset of asthma, it's clear, I hope, from the foregoing discussion that the Nonremitting children all suffer from conflicts arising in the anal period of development. This is not so (or much less so) for the Rapidly Remitting children who, however, often have conflicts which are just as severe. Each of the Nonremitting children, on an unconscious level, is waging a battle with mother over who will get the upper hand: this is the central conflict. Though these children are outwardly compliant much

  3. Comparative study of homotopy continuation methods for nonlinear algebraic equations

    NASA Astrophysics Data System (ADS)

    Nor, Hafizudin Mohamad; Ismail, Ahmad Izani Md.; Majid, Ahmad Abd.

    2014-07-01

    We compare some recent homotopy continuation methods to see which method has greater applicability and greater accuracy. We test the methods on systems of nonlinear algebraic equations. The results obtained indicate the superior accuracy of Newton Homotopy Continuation Method (NHCM).

  4. Randomized study comparing inflammatory response after tonsillectomy versus tonsillotomy.

    PubMed

    Kordeluk, Sofia; Goldbart, Aviv; Novack, Lena; Kaplan, Daniel Michael; El-Saied, Sabri; Alwalidi, Musa; Shapira-Parra, Angelica; Segal, Nili; Slovik, Yuval; Max, Puterman; Joshua, Ben-Zion

    2016-11-01

    To determine if there was a difference in the inflammatory reaction after tonsil surgery with "traditional" techniques (tonsillectomy and adenoidectomy or TA) compared to partial intracapsular tonsillectomy and adenoidectomy (PITA).

  5. Dosimetry and microdosimetry using COTS ICs: A comparative study

    NASA Technical Reports Server (NTRS)

    Scheick, L.; Swift, G.; Guertin, S.; Roth, D.; McNulty, P.; Nguyen, D.

    2002-01-01

    A new method using an array of MOS transistors formeasuring dose absorbed from ionizing radiation is compared to previous dosimetric methods., The accuracy and precision of dosimetry based on COTS SRAMs, DRAMs, and WPROMs are compared and contrasted. Applications of these devices in various space missions will be discussed. TID results are presented for this summary and microdosimetricresults will be added to the full paper. Finally, an analysis of the optimal condition for a digital dosimeter will be presented.

  6. Radiography and sonography of clubfoot: A comparative study

    PubMed Central

    Bhargava, Satish Kumar; Tandon, Anupama; Prakash, Meenakshi; Arora, Shobha S; Bhatt, Shuchi; Bhargava, Sumeet

    2012-01-01

    Background: Congenital talipes equinovarus is a common foot deformity afflicting children with reported incidence varying from 0.9/1000 to 7/1000 in various populations. The success reported with Ponseti method when started at an early age requires an imaging modality to quantitate the deformity. Sonography being a radiation free, easily available non-invasive imaging has been investigated for this purpose. Various studies have described the sonographic anatomy of normal neonatal foot and clubfoot and correlated the degree of severity with trends in sonographic measurements. However, none of these studies have correlated clinical, radiographic and sonographic parameters of all the component deformities in clubfoot. The present study aims to compare the radiographic and sonographic parameters in various grades of clubfoot. Materials and Methods: Thirty-one children with unilateral clubfoot were examined clinically and graded according to the Demeglio system of classification of clubfoot severity. Antero-posterior (AP) and lateral radiographs of both normal and affected feet were obtained in maximum correction and AP talo-calcaneal (T-C), AP talo-first metatarsal (TMT) and lateral T-C angles were measured. Sonographic examination was done in medial, lateral, dorsal and posterior projections of both feet in static neutral position and after Ponseti manouever in the position of maximum correctability in dynamic sonography. Normal foot was taken as control in all cases. The sonographic parameters measured were as follows : Medial malleolar- navicular distance (MMN) and medial soft tissue thickness (STT) on medial projection, calcaneo-cuboid (C-C) distance, calcaneo-cuboid (C-C) angle and maximum length of calcaneus on lateral projection, length of talus on dorsal projection; and tibiocalcaneal (T-C) distance, posterior soft tissue thickness and length of tendoachilles on posterior projection. Also, medial displacement of navicular relative to talus, mobility of

  7. A comparative study about learning styles preferences of two cultures

    NASA Astrophysics Data System (ADS)

    Kutay, Huban

    From an anthropologist's (Maddock, 1981) point of view, "science and science education are cultural enterprises which form a part of the wider cultural matrix of society and educational considerations concerning science must be made in the light of this wider perspective" (p.10). In addition, Spindler (1987) states that teaching science is considered cultural transmission while, Wolcott (1991) focuses on learning science as culture acquisition. In these statements, culture is defined as "an ordered system of meaning and symbols, in terms of which social interaction takes place" (Geertz, 1973). Thus, learning and culture are a partnership. Jones and Fennimore (1990) state: "Every culture brings habits of thought, resources, and context, which have built into them vehicles that promote learning and inquiry. Accordingly, children of any culture can and should have curriculum and instructional practices that draw from that culture." (p.16). Unfortunately, even though this statement is probably accurate, most schools still use the same curriculum, instructional methods, and assessment strategies for all students regardless of their differences in learning styles. The purpose of this study is to identify the relationship between students' learning styles and their culture. This is a correlational study. Does culture limit or expand the learning of individuals? For this study Turkish students who graduated from a Turkish high school and undertook undergraduate education in the United States or finished their undergraduate education in Turkey and pursued graduate education in the United States were identified. These Turkish subjects were compared to American college students through learning styles data and anxiety levels as cultural markers. To identify individuals' learning styles we used the Building Excellence (BE) instrument, which is an adult version of The Learning Style Inventory by Dunn, and Rundle (1996.1997, 1998, 1999, and 2000). BE assesses twenty four

  8. Comparative study of different waste biomass for energy application.

    PubMed

    Motghare, Kalyani A; Rathod, Ajit P; Wasewar, Kailas L; Labhsetwar, Nitin K

    2016-01-01

    Biomass is available in many varieties, consisting of crops as well as its residues from agriculture, forestry, and the agro-industry. These different biomass find their way as freely available fuel in rural areas but are also responsible for air pollution. Emissions from such solid fuel combustion to indoor, regional and global air pollution largely depend on fuel types, combustion device, fuel properties, fuel moisture, amount of air supply for combustion and also on climatic conditions. In both economic and environment point of view, gasification constitutes an attractive alternative for the use of biomass as a fuel, than the combustion process. A large number of studies have been reported on a variety of biomass and agriculture residues for their possible use as renewable fuels. Considering the area specific agriculture residues and biomass availability and related transportation cost, it is important to explore various local biomass for their suitability as a fuel. Maharashtra (India) is the mainstay for the agriculture and therefore, produces a significant amount of waste biomass. The aim of the present research work is to analyze different local biomass wastes for their proximate analysis and calorific value to assess their potential as fuel. The biomass explored include cotton waste, leaf, soybean waste, wheat straw, rice straw, coconut coir, forest residues, etc. mainly due to their abundance. The calorific value and the proximate analysis of the different components of the biomass helped in assessing its potential for utilization in different industries. It is observed that ash content of these biomass species is quite low, while the volatile matter content is high as compared to Indian Coal. This may be appropriate for briquetting and thus can be used as a domestic fuel in biomass based gasifier cook stoves. Utilizing these biomass species as fuel in improved cook-stove and domestic gasifier cook-stoves would be a perspective step in the rural energy and

  9. Comparative study on dermatoglyphics in patients with PTSD.

    PubMed

    Glamuzina, Ljubomir; Mihanović, Mate; Milicić, Jasna; Devcić, Sanja; Restek-Petrović, Branka

    2009-12-01

    The factors situated at the bases of the genesis and development of PTSD are divided in: biological, psychological and social factors. Primary factor is a stressful event of extremely dangerous and threatening nature. The sort and the intensity of the stressful event too play an important role, followed by the personality structure, the relation with the environment and the genetic constitution. The study was thought to determine the quantitative dermatoglyphic properties of the digito-palmar complex in patients with PTSD aiming to establish whether there are biological, that is, genetic bases for PTSD, in what measure they determine the clinical manifestation of the disorder, and whether there is a dermatoglyphic marker, characteristic for people with PTSD. We analyzed the quantitative properties of the digito-palmer complex on a group of 100 male examinees over 18 years of age with PTSD, no psychiatric comorbidity, and who were two or more times cured at the Psychiatric Hospital "Sveti Ivan", comparing them with the quantitative dermatoglyphic properties of a group of 100 phenotypically healthy male examinees over 18 years of age. Using the method of descriptive statistics, we found no statistically significant differences among the results of the examined groups. With the T-test we evaluated the heterogeneity of the groups, and the results showed the existence of statistically significant differences among the comparison group and the group of patients with PTSD on three variables. We calculated the Fluctuating Asymmetry (FA) measure, which illustrates the compatibility, that is, the symmetry of the observed property on the right and on the left side of the body, indicating a difference on one variable. The outcome did not confirm the existence of a connection between a particular dermatoglyphic result and the genesis of PTSD. This is, however, in line with the hypothesis that, in patients with PTSD and other psychiatric disorders, there is a multiple effect of

  10. Histomorphometric and microchemical characterization of maturing dental enamel in rats fed a boron-deficient diet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Few reports are available in the literature on enamel formation under nutritional deficiencies. Continuously erupting rodent incisors have considerable potential to serve as a model system for amelogenesis. Thus, we performed a study to determine the effects of boron (B) deficiency on the maturing d...

  11. PROSPECTIVE RANDOMIZED STUDY COMPARING TWO ANESTHETIC METHODS FOR SHOULDER SURGERY

    PubMed Central

    Ikemoto, Roberto Yukio; Murachovsky, Joel; Prata Nascimento, Luis Gustavo; Bueno, Rogerio Serpone; Oliveira Almeida, Luiz Henrique; Strose, Eric; de Mello, Sérgio Cabral; Saletti, Deise

    2015-01-01

    Objective: To evaluate the efficacy of suprascapular nerve block in combination with infusion of anesthetic into the subacromial space, compared with interscalene block. Methods: Forty-five patients with small or medium-sized isolated supraspinatus tendon lesions who underwent arthroscopic repair were prospectively and comparatively evaluated through random assignation to three groups of 15, each with a different combination of anesthetic methods. The efficacy of postoperative analgesia was measured using the visual analogue scale for pain and the analgesic, anti-inflammatory and opioid drug consumption. Inhalation anesthetic consumption during surgery was also compared between the groups. Results: The statistical analysis did not find any statistically significant differences among the groups regarding anesthetic consumption during surgery or postoperative analgesic efficacy during the first 48 hours. Conclusion: Suprascapular nerve block with infusion of anesthetic into the subacromial space is an excellent alternative to interscalene block, particularly in hospitals in which an electrical nerve stimulating device is unavailable. PMID:27022569

  12. Digital photogrammetry and histomorphometric assessment of the effect of non-coherent light (light-emitting diode) therapy (λ640 ± 20 nm) on the repair of third-degree burns in rats.

    PubMed

    Neves, Silvana Maria Véras; Nicolau, Renata Amadei; Filho, Antônio Luiz Martins Maia; Mendes, Lianna Martha Soares; Veloso, Ana Maria

    2014-01-01

    Recent studies have demonstrated the efficacy of coherent light therapy from the red region of the electromagnetic spectrum on the tissue-healing process. This study analysed the effect of non-coherent light therapy (light-emitting diode-LED) with or without silver sulfadiazine (sulpha) on the healing process of third-degree burns. In this study, 72 rats with third-degree burns were randomly divided into six groups (n = 12): Gr1 (control), Gr2 (non-contact LED), Gr3 (contact LED), Gr4 (sulfadiazine), Gr5 (sulfadiazine + non-contact LED) and Gr6 (sulfadiazine + contact LED). The groups treated with LED therapy received treatment every 48 h (λ = 640 ± 20 nm, 110 mW, 16 J/cm(2); 41 s with contact and 680 s without contact). The digital photometric and histomorphometric analyses were conducted after the burn occurred. The combination of sulpha and LED (contact or non-contact) improved the healing of burn wounds. These results demonstrate that the combination of silver sulfadiazine with LED therapy (λ = 640 ± 20 nm, 4 J/cm(2), without contact) improves healing of third-degree burn wounds, significantly reduces the lesion area and increases the granulation tissue, increases the number of fibroblasts, promotes collagen synthesis and prevents burn infections by accelerating recovery.

  13. Cell Kinetic and Histomorphometric Analysis of Microgravitational Osteopenia: PARE.03B

    NASA Technical Reports Server (NTRS)

    Roberts, W. Eugene; Garetto, Lawrence P.

    1998-01-01

    Previous methods of identifying cells undergoing DNA synthesis (S-phase) utilized 3H-thymidine (3HT) autoradiography. 5-Bromo-2'-deoxyuridine (BrdU) immunohistochemistry is a nonradioactive alternative method. This experiment compared the two methods using the nuclear volume model for osteoblast histogenesis in two different embedding media. Twenty Sprague-Dawley rats were used, with half receiving 3HT (1 micro-Ci/g) and the other half BrdU (50 micro-g/g). Condyles were embedded (one side in paraffin, the other in plastic) and S-phase nuclei were identified using either autoradiography or immunohistochemistry. The fractional distribution of preosteoblast cell types and the percentage of labeled cells (within each cell fraction and label index) were calculated and expressed as mean +/- standard error. Chi-Square analysis showed only a minor difference in the fractional distribution of cell types. However, there were,significant differences (p less than 0.05) by ANOVA, in the nuclear labeling of specific cell types. With the exception of the less-differentiated A+A' cells, more BrdU label was consistently detected in paraffin than in plastic-embedded sections. In general, more nuclei were labeled with 3H-thymidine than with BrdU in both types of embedding media (Fig 2.). Labeling index data (labeled cells/total cells sampled x 100) indicated that BrdU in paraffin, but not plastic gave the same results as 3HT in either embedding method. Thus, we conclude that the two labeling methods do not yield the same results.

  14. Cell Kinetic and Histomorphometric Analysis of Microgravitational Osteopenia: PARE.03B

    NASA Technical Reports Server (NTRS)

    Roberts, W. Eugene; Garetto, Lawrence P.

    1998-01-01

    Previous methods of identifying cells undergoing DNA synthesis (S-phase) utilized H-3 thymidine (3HT) autoradiography. 5-Bromo-2'-deoxyuridine (BrdU) immunohistochemistry is a nonradioactive alternative method. This experiment compared the two methods using the nuclear volume model for osteoblast histogenesis in two different embedding media. Twenty Sprague-Dawley rats were used, with half receiving 3HT (1 micro Ci/g) and the other half BrdU (50 microgram/g). Condyies were embedded (one side in paraffin, the other in plastic) and S-phase nuclei were identified using either autoradiography or immunohistochemistry. The fractional distribution of preosteoblast cell types and the percentage of labeled cells (within each cell fraction and label index) were calculated and expressed as mean q standard error. Chi-Square analysis showed only a minor difference in the fractional distribution of cell types. However, there were significant differences (p less than 0.05) by ANOVA, in the nuclear labeling of specific cell types. With the exception of the less-differentiated A+A'cells, more BrdU label was consistently detected in paraffin than in plastic-embedded sections. In general, more nuclei were labeled with 3H-thymidine than with BrdU in both types of embedding media. Labeling index data (labeled cells/total cells sampled x 100) indicated that BrdU in paraffin, but not plastic gave the same results as 3HT in either embedding method. Thus, we conclude that the two labeling methods do not yield the same results for the nuclear volume model and that embedding media is an important factor whenusing BrdU. As a result of this work, 3HT was chosen for used in the PARE.03 flight experiments.

  15. Structures of School Systems Worldwide: A Comparative Study

    ERIC Educational Resources Information Center

    Popov, Nikolay

    2012-01-01

    In the past 20 years I have been examining the structures of school systems worldwide. This ongoing research has been enriched by the findings obtained from the lecture course on Comparative Education I have been delivering to students in the Bachelor and Master's Education Programs at Sofia University, Bulgaria. This paper presents some results…

  16. Automated Essay Scoring versus Human Scoring: A Comparative Study

    ERIC Educational Resources Information Center

    Wang, Jinhao; Brown, Michelle Stallone

    2007-01-01

    The current research was conducted to investigate the validity of automated essay scoring (AES) by comparing group mean scores assigned by an AES tool, IntelliMetric [TM] and human raters. Data collection included administering the Texas version of the WriterPlacer "Plus" test and obtaining scores assigned by IntelliMetric [TM] and by…

  17. Neural Networks for Language Identification: A Comparative Study.

    ERIC Educational Resources Information Center

    MacNamara, Shane; Cunningham, Padraig; Byrne, John

    1998-01-01

    Analyzes a neural network for its ability to perform a task involving identification of the language entries in a 19th-century library catalog containing entries in 14 different languages. Compares the neural network's performance with that of trigrams and a suffix/morphology analysis; the trigrams prove to be superior. (AEF)

  18. Vocation, Motivation and Approaches to Learning: A Comparative Study

    ERIC Educational Resources Information Center

    Arquero, Jose Luis; Fernández-Polvillo, Carmen; Hassall, Trevor; Joyce, John

    2015-01-01

    Purpose: The individual characteristics of students can have a strong influence on the success of the adopted innovations in terms of their transferability and sustainability. The purpose of this paper is to compare the motivations and approaches to learning on degrees with differing vocational components. Design/methodology/approach:…

  19. Comparative Study of Student Support Services of UKOU and SLOU

    ERIC Educational Resources Information Center

    Gujjar, Aijaz Ahmed; Choudhry, Bushra Naoreen; Choudhry, Amtul Hafeez

    2008-01-01

    This paper attempts to compare the availability, quality, similarities and differences of students' support services in United Kingdom Open University (UKOU) and Sri Lanka Open University (SLOU) and also to identify and enlist the deficiencies that SLOU students are facing in the student support services. To get the desired end four hundred…

  20. Parental Bereavement after Suicide and Accident: A Comparative Study.

    ERIC Educational Resources Information Center

    Seguin, Monique; And Others

    1995-01-01

    Compares differences in the bereavement process for 30 survivors of suicide versus 30 survivors of car accidents. Indicates suicide survivors were more depressed than accident survivors at the first measure but not at the second measure. Survivors of suicide experienced greater feelings of shame and had experienced more life events after the death…

  1. A Corpus-Based Comparative Study of "Learn" and "Acquire"

    ERIC Educational Resources Information Center

    Yang, Bei

    2016-01-01

    As an important yet intricate linguistic feature in English language, synonymy poses a great challenge for second language learners. Using the 100 million-word British National Corpus (BNC) as data and the software Sketch Engine (SkE) as an analyzing tool, this article compares the usage of "learn" and "acquire" used in natural…

  2. An Experimental Study of Job Evaluation and Comparable Worth.

    ERIC Educational Resources Information Center

    Arnault, E. Jane; Gordon, Louis; Joines, Douglas H.; Phillips, G. Michael

    2001-01-01

    Three commercial job evaluation firms rated the same set of 27 jobs. Statistical analysis indicated that evaluators differed in which job traits they used to evaluate inherent job worth. Comparable worth may thus be sensitive to the choice of evaluator. (Contains 24 references.) (Author/SK)

  3. Cognitive and Creative Thinking: A Comparative Study among Filipino Children.

    ERIC Educational Resources Information Center

    Naval-Severino, Teresita

    1993-01-01

    A group of nine Filipino children (ages five to nine) from disadvantaged backgrounds received training in higher level cognitive thinking skills and was compared to a control group that received no training. The training program was based on Benjamin Bloom's cognitive levels of thinking. Students receiving the training showed better performance on…

  4. Social Cartography: A New Methodology for Comparative Studies.

    ERIC Educational Resources Information Center

    Liebman, Martin; Paulston, Rolland

    Comparative educators can enhance research by developing and including in their research findings a cognitive map to show perceptions of how knowledge claims interrelate. Three research relationships utilize different methodologies: (1) the researcher objectifies the phenomena; (2) the researcher position is preferential to the research object but…

  5. Reforming Teaching Globally. Oxford Studies in Comparative Education

    ERIC Educational Resources Information Center

    Tatto, Maria Teresa, Ed.

    2007-01-01

    This book seeks to raise the discussion of globalisation's effects on teacher education, development and work, and its reforms and institutions, to a more theoretical and analytical level, and to provide specific examples in the comparative tradition to illustrate teacher policy in the context of education systems' widespread variability and…

  6. Comparative Actions of Barbiturates Studied by Pollen Grain Germination.

    ERIC Educational Resources Information Center

    Kordan, Herbert A.; Mumford, Pauline M.

    1979-01-01

    Describes a simple experimental system whereby the comparative actions of long, medium, and short-acting barbiturates can be demonstrated in a relatively short period of time under optical microscopy using pollen grains as the biological test or assay system. (Author/HM)

  7. Teaching Organic Synthesis: A Comparative Case Study Approach

    ERIC Educational Resources Information Center

    Vosburg, David A.

    2008-01-01

    In this course, students encounter reactions and mechanisms in the context of landmark syntheses of biologically important molecules. Students closely examine pairs of syntheses of related or identical molecules to facilitate their appreciation for synthetic strategy. They then write short, creative papers that critically compare the two synthetic…

  8. Psychiatric Diagnostic Interviews for Children and Adolescents: A Comparative Study

    ERIC Educational Resources Information Center

    Angold, Adrian; Erkanli, Alaattin; Copeland, William; Goodman, Robert; Fisher, Prudence W.; Costello, E. Jane

    2012-01-01

    Objective: To compare examples of three styles of psychiatric interviews for youth: the Diagnostic Interview Schedule for Children (DISC) ("respondent-based"), the Child and Adolescent Psychiatric Assessment (CAPA) ("interviewer-based"), and the Development and Well-Being Assessment (DAWBA) ("expert judgment"). Method: Roughly equal numbers of…

  9. Histomorphometric and electron microscopic analyses of tibial epiphyseal plates from Cosmos 1887 rats

    NASA Technical Reports Server (NTRS)

    Duke, P. J.; Durnova, G.; Montufar-Solis, D.

    1990-01-01

    Previous studies have shown that the changes seen in the bones of growing rats exposed to microgravity are due in part to changes that occur in the growth plate during spaceflight. In this study, growth plates of rats flown aboard Cosmos 1887 (12.5-day flight plus 53.5-h recovery at 1 g) were analyzed using light and electron microscopy and computerized planimetry. The proliferative zone of flight animals was found to be significantly (P less than or equal to 0.01) larger than that of controls, while the reserve and hypertrophic/calcification zones were significantly reduced. Flight animals also had more cells per column in the proliferative zone than did controls and less in the hypertrophic/calcification region. The total number of cells, however, was significantly greater in flight animals. No difference was found in perimeter or in shape factor, but area was significantly less in flight animals. Electron microscopy showed that collagen fibrils in flight animals were wider than in controls. Since the time required for a cell to cycle through the growth plate is 2-3 days at 1 g, the results reported here represent both the effects of exposure to microgravity and the initial stages of recovery from that exposure.

  10. Comparative study of icy patches on comet nuclei

    NASA Astrophysics Data System (ADS)

    Oklay, Nilda; Pommerol, Antoine; Barucci, Maria Antonietta; Sunshine, Jessica; Sierks, Holger; Pajola, Maurizio

    2016-07-01

    Cometary missions Deep Impact, EPOXI and Rosetta investigated the nuclei of comets 9P/Tempel 1, 103P/Hartley 2 and 67P/Churyumov-Gerasimenko respectively. Bright patches were observed on the surfaces of each of these three comets [1-5]. Of these, the surface of 67P is mapped at the highest spatial resolution via narrow angle camera (NAC) of the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS, [6]) on board the Rosetta spacecraft. OSIRIS NAC is equipped with twelve filters covering the wavelength range of 250 nm to 1000 nm. Various filters combinations are used during surface mapping. With high spatial resolution data of comet 67P, three types of bright features were detected on the comet surface: Clustered, isolated and bright boulders [2]. In the visible spectral range, clustered bright features on comet 67P display bluer spectral slopes than the average surface [2, 4] while isolated bright features on comet 67P have flat spectra [4]. Icy patches observed on the surface of comets 9P and 103P display bluer spectral slopes than the average surface [1, 5]. Clustered and isolated bright features are blue in the RGB composites generated by using the images taken in NIR, visible and NUV wavelengths [2, 4]. This is valid for the icy patches observed on comets 9P and 103P [1, 5]. Spectroscopic observations of bright patches on comets 9P and 103P confirmed the existence of water [1, 5]. There were more than a hundred of bright features detected on the northern hemisphere of comet 67P [2]. Analysis of those features from both multispectral data and spectroscopic data is an ongoing work. Water ice is detected in eight of the bright features so far [7]. Additionally, spectroscopic observations of two clustered bright features on the surface of comet 67P revealed the existence of water ice [3]. The spectral properties of one of the icy patches were studied by [4] using OSIRIS NAC images and compared with the spectral properties of the active regions observed

  11. Ultraviolet radiation penetrating vehicle glass: a field based comparative study

    NASA Astrophysics Data System (ADS)

    Kimlin, M. G.; Parisi, A. V.

    1999-04-01

    The solar UV transmitted through automobile glass was measured in the field in two cars using a spectroradiometer. The two cars were identical except that one of the cars had all of the windows (except the windshield) tinted. The measured spectral erythemal UV on a horizontal plane with the windows fully closed was reduced in the tinted car by a factor of 42 when compared with the erythemal UV measured in the untinted car. The ambient UVA irradiances at various locations within four different makes of car and a tractor were also measured with a broad band UVA hand-held meter. The average normalized daily UVA exposure (measured with a broad band UVA meter) was 1.3 times higher in a large family sedan when compared with that in a small hatchback and the UVA exposure in a car with tinted windows was 3.8 times less than in a similar untinted car.

  12. Comparative study on methodology in molecular dynamics simulation of nucleation

    NASA Astrophysics Data System (ADS)

    Julin, Jan; Napari, Ismo; Vehkamäki, Hanna

    2007-06-01

    Gas-liquid nucleation of 1000 Lennard-Jones atoms is simulated to evaluate temperature regulation methods and methods to obtain nucleation rate. The Berendsen and the Andersen thermostats are compared. The Berendsen thermostat is unable to control the temperature of clusters larger than the critical size. Independent of the thermostating method the velocities of individual atoms and the translational velocities of clusters up to at least six atoms are accurately described by the Maxwell velocity distribution. Simulations with the Andersen thermostat yield about two times higher nucleation rates than those with the Berendsen thermostat. Nucleation rate is extracted from the simulations by direct observation of times of nucleation onset and by the method of Yasuoka and Matsumoto [J. Chem. Phys. 109, 8451 (1998)]. Compared to the direct observation, the nucleation rates obtained from the method of Yasuoka and Matsumoto are higher by a factor of 3.

  13. A comparative study of young and mature bovine cortical bone.

    PubMed

    Manilay, Zherrina; Novitskaya, Ekaterina; Sadovnikov, Ernest; McKittrick, Joanna

    2013-02-01

    The mechanical properties and microstructure of young and mature bovine femur bone were investigated by optical microscopy and compression testing in the longitudinal and transverse directions for untreated, deproteinized and demineralized cases. Optical microscopy revealed that mature bone has a more established and less porous microstructure compared to young bone. Mature bone was found to be stronger in both directions for the untreated and deproteinized cases. Mature untreated bone was also found to be stiffer and less tough compared to young bone in both directions. These results are related to the increase in mineralization of mature bone and significant microstructural differences. Young bone was found to be stronger in both directions for the demineralized case, which is attributed to alterations in the collagen network with age.

  14. Clinical characteristics and outcomes of neonatal pertussis: a comparative study.

    PubMed

    Castagnini, Luis A; Munoz, Flor M

    2010-03-01

    We describe the features and outcomes of neonatal pertussis and compare these with neonates with non-pertussis acute respiratory illness from July 2000 through December 2007. Patients with pertussis had a more severe course of disease as evidenced by the clinical presentation, length of hospitalization, and oxygen requirement. Clinicians should have a high index of suspicion so that appropriate supportive care can be initiated promptly.

  15. A comparative study of clock rate and drift estimation

    NASA Technical Reports Server (NTRS)

    Breakiron, Lee A.

    1994-01-01

    Five different methods of drift determination and four different methods of rate determination were compared using months of hourly phase and frequency data from a sample of cesium clocks and active hydrogen masers. Linear least squares on frequency is selected as the optimal method of determining both drift and rate, more on the basis of parameter parsimony and confidence measures than on random and systematic errors.

  16. A comparative study of electric power distribution systems for spacecraft

    NASA Technical Reports Server (NTRS)

    Stuart, Thomas A.; King, Roger J.

    1990-01-01

    The electric power distribution systems for spacecraft are compared concentrating on two interrelated issues: the choice between dc and high frequency ac, and the converter/inverter topology to be used at the power source. The relative merits of dc and ac distribution are discussed. Specific converter and inverter topologies are identified and analyzed in detail for the purpose of detailed comparison. Finally, specific topologies are recommended for use in dc and ac systems.

  17. The value of the Piagetian framework for comparative cognitive studies.

    PubMed

    Pepperberg, Irene M

    2002-09-01

    Although the Piagetian framework has been used by numerous researchers to compare cognitive abilities of diverse species, the system is often criticized as implemented. I examine the various criticisms, suggest ways in which the system can be improved, and argue for the need for descriptive systems such as the Piagetian framework to complement programs that look for cellular and molecular bases or mathematical models to explain behavior.

  18. Comparative study of contaminant levels in Long Island Sound

    SciTech Connect

    Robertson, A.; Gottholm, B.W.; Turgeon, D.D.; Wolfe, D.A. )

    1991-09-01

    This paper uses results from the National Oceanic and Atmospheric Administration's National Status and Trends Program (NS and T) to place the environmental quality of Long Island Sound in a broader perspective. It compares levels of contaminants in blue mussels from ten Long Island Sound sites and in sediments from seven Long Island Sound sites with concentrations in the same media at 87 and 221 other sites, respectively, where comparable samples were obtained. In sediments, the levels of both trace metals and organic contaminants tend to be relatively high for Long Island sites. This is especially true for five of the twelve metals (silver, cadmium, copper, lead, and zinc) and for five of six categories of organic contaminants (total chlordane, low molecular weight polycyclic aromatic hydrocarbons (PAHs), high molecular weight PAHs, total polychlorinated biphenyls, and total dichlorodiphenyltrichloroethanes). In mussels, the organic contaminant categories exhibit relatively high levels, but this is not true for most of the metals. In fact, four of the metals-arsenic, mercury, selenium, and zinc - show evidence of relatively low levels in mussels from Long Island Sound compared to other NS and T locations.

  19. Histomorphometric Analysis of Cutaneous Remodeling in the Early Stage of the Scleroderma Model

    PubMed Central

    de Oliveira, Cristiane Carla; Velosa, Ana Paula Pereira; Parra, Edwin Roger; Capelozzi, Vera Luiza; Teodoro, Walcy Rosolia; Yoshinari, Natalino Hajime

    2009-01-01

    INTRODUCTION/OBJECTIVES Systemic sclerosis, or scleroderma, is a rheumatic disease characterized by autoimmunity, vasculopathy, and fibrosis of the skin and several internal organs. In the present study, our aim was to assess the skin alterations in animals with scleroderma during the first stages of disease induction. METHODS: To induce scleroderma, female New Zealand rabbits (n = 12) were subcutaneously immunized with 1 mg/ml of collagen V (Col V) in complete Freund’s adjuvant, twice with a thirty-day interval. Fifteen days later, the animals received an intramuscular booster with type V collagen in incomplete Freund’s adjuvant, twice with a fifteen-day interval. The control group was inoculated with 1 ml of 10 mM acetic acid solution diluted with an equal amount of Freund’s adjuvant. Serial dorsal skin biopsies were performed at 7, 15, and 30 days and stained with H&E, Masson’s trichrome and Picrosírius for morphological and morphometric analyses. RESULTS: Immunized rabbits presented a significant increase in collagen in skin collected seven days after the first immunization (p=0.05). CONCLUSION: The results from this experimental model may be very important to a better understanding of the pathogenic mechanisms involved in the beginning of human SSc. Therapeutic protocols to avoid early remodeling of the skin may lead to promising treatments for SSc in the future. PMID:19578663

  20. Histomorphometric analysis of the effects of osteocyte density on osteonal morphology and remodeling.

    PubMed

    Metz, Lionel N; Martin, R Bruce; Turner, A Simon

    2003-11-01

    Osteocytes, the most abundant cells in the cortical bone matrix, are thought to have mechanosensory and chemosensory regulatory roles. Marotti theorized that osteocytes signal to osteoblasts to recruit them into the osteocyte lineage. Martin extended this theory, assuming that osteocytes display a general inhibitory effect on osteoblast function. The current study provides a quantitative analysis of the relationships between osteonal osteocyte density (Ot.N/BV), wall width (W.Wi), individual osteon porosity (IOP), and formation period (FP) in ulnar cortices from sheep labeled with tetracycline and calcein double labels. We postulated that osteocytes inhibit refilling so that the osteon wall width is thin enough, and the haversian canal is large enough, to allow adequate delivery of nutrients to the osteocytes throughout the forming and completed osteon. Therefore we tested the hypotheses that Ot.N/BV correlates negatively to FP and W.Wi, and positively to IOP, and that FP correlates positively with W.Wi. We found that Ot.N/BV correlated positively with IOP (P < 0.0001) and W.Wi correlated positively with FP (P < 0.0001). Significant negative correlations were observed between Ot.N/BV and both W.Wi (P < 0.0001) and FP (P = 0.006). These data support the general hypothesis that osteocytes contribute to the regulation of osteon morphology via the control of refilling rate and formation period, and the specific hypotheses that, for a given cement line diameter, high osteocyte density (1) reduces the rate of refilling and decreases the formation period and (2) decreases wall width and increases individual osteon porosity.

  1. Comparative studies of Toll-like receptor signalling using zebrafish.

    PubMed

    Kanwal, Zakia; Wiegertjes, Geert F; Veneman, Wouter J; Meijer, Annemarie H; Spaink, Herman P

    2014-09-01

    Zebrafish model systems for infectious disease are increasingly used for the functional analysis of molecular pattern recognition processes. These studies benefit from the high conservation level of all innate immune factors in vertebrates. Zebrafish studies are strategically well positioned for this because of the ease of comparisons with studies in other fish species of which the immune system also has been intensively studied, but that are currently still less amendable to detailed genetic or microscopic studies. In this paper we focus on Toll-like receptor (TLR) signalling factors, which currently are the best characterized in mammalian systems. We review the knowledge on TLR signalling in the context of recent advances in zebrafish studies and discuss possibilities for future approaches that can complement studies in cell cultures and rodent models. A focus in these comparisons is the role of negative control mechanisms in immune responses that appear very important in a whole organism to keep adverse systemic responses in check. We also pay much attention to comparisons with studies in common carp that is highly related to zebrafish and that because of its large body mass can complement immune studies in zebrafish.

  2. Selenium and sulfur in exchange reactions: a comparative study.

    PubMed

    Steinmann, Daniel; Nauser, Thomas; Koppenol, Willem H

    2010-10-01

    Cysteamine reduces selenocystamine to form hemiselenocystamine and then cystamine. The rate constants are k(1) = 1.3 × 10(5) M(-1) s(-1); k(-1) = 2.6 × 10(7) M(-1) s(-1); k(2) = 11 M(-1) s(-1); and k(-2) = 1.4 × 10(3) M(-1) s(-1), respectively. Rate constants for reactions of cysteine/selenocystine are similar. Reaction rates of selenium as a nucleophile and as an electrophile are 2-3 and 4 orders of magnitude higher, respectively, than those of sulfur. Sulfides and selenides are comparable as leaving groups.

  3. Comparative study of solar optics for paraboloidal concentrators

    NASA Technical Reports Server (NTRS)

    Wen, L.; Poon, P.; Carley, W.; Huang, L.

    1979-01-01

    Different analytical methods for computing the flux distribution on the focal plane of a paraboloidal solar concentrator are reviewed. An analytical solution in algebraic form is also derived for an idealized model. The effects resulting from using different assumptions in the definition of optical parameters used in these methodologies are compared and discussed in detail. These parameters include solar irradiance distribution (limb darkening and circumsolar), reflector surface specular spreading, surface slope error, and concentrator pointing inaccuracy. The type of computational method selected for use depends on the maturity of the design and the data available at the time the analysis is made.

  4. Exafs and comparative studies of copper (II) complexes

    NASA Astrophysics Data System (ADS)

    Mishra, A.; Mishra, S.

    2016-10-01

    The present paper deals with the synthesis of transition metal Schiff base complexes of copper by chemical root method. The synthesized metal complexes were characterized by Extended X-ray absorption fine structure (EXAFS) is a technique that has been used for determining the metal ligand bond length using conventional X-ray source and also by EXAFS analysis using IFEFFIT programming. Bond lengths determined from these data analysis methods are compared with the bond lengths obtained from LSS, Levy's and Lytle's methods. Bond lengths of the complexes are in good agreement obtained by theoretical and experimental method.

  5. An in vivo comparative study of two apex locators.

    PubMed

    Pallarés, A; Faus, V

    1994-12-01

    Two different electronic apex locators were used before extraction to determine working length in 116 root canals belonging to 34 molars. The results were then compared with postextraction working length measurements. The determinations were made before and after eliminating the canal contents and drying the interior. The results showed that 84.8% and 79.3% of the Odometer, and 89.6% and 88.7% of the Endocater readings for dry and nondry canals, respectively, occurred within the two 0.5-mm intervals closest to the apical constriction.

  6. Policies for Minority Education. A Comparative Study of Britain and Sweden. Studies in Comparative and International Education, No. 7.

    ERIC Educational Resources Information Center

    Fris, Ann-Margret

    This document examines and compares how policies for minority education in Great Britain and Sweden have developed over the last 25 years. The term "policy" is used here broadly and includes not only central but also regional decisions, and written documents as well as administration, interpretation, and application of policies. The…

  7. Comparing International Curriculum Systems: The International Instructional Systems Study

    ERIC Educational Resources Information Center

    Creese, Brian; Gonzalez, Alvaro; Isaacs, Tina

    2016-01-01

    This paper sets out the main findings of the International Instructional Systems Study (IISS), conducted by the UCL Institute of Education and funded by the Center on International Education Benchmarking (CIEB). The study examined the instructional systems and intended curricula of six "high performing" countries and two US states. The…

  8. Strategy Maps in University Management: A Comparative Study

    ERIC Educational Resources Information Center

    Han, Shuangmiao; Zhong, Zhou

    2015-01-01

    In this study, the conceptual use of the strategy map approach and the strategy map which it produces have been adapted from the business sector and introduced as tools for achieving more effective strategic planning and management in higher education institutions (HEIs). This study discusses the development of strategy maps as transformational…

  9. Youth Studies, Comparative Inquiry, and the Local/Global Problematic

    ERIC Educational Resources Information Center

    McLeod, Julie

    2009-01-01

    The field of youth studies appears to have increasingly taken on a self-consciously "international" orientation, characterized by grappling with how to represent local youth identities and social practices within international, transnational, or global contexts. This challenge is repeated across many different types of study and worked…

  10. Asperger Syndrome and Schizophrenia: A Comparative Neuropsychological Study

    ERIC Educational Resources Information Center

    Marinopoulou, Maria; Lugnegård, Tove; Unenge Hallerbäck, Maria; Gillberg, Christopher; Billstedt, Eva

    2016-01-01

    There has been an increasing interest in possible connections between autism spectrum disorder (ASD) and schizophrenia in the last decade. Neuropsychological comparison studies have, however, been few. The present study examined similarities and differences in intellectual and executive functioning between adults with Asperger syndrome (AS) and…

  11. Metafunctional Practices in Medical Research Articles: A Comparative Study

    ERIC Educational Resources Information Center

    Assadi, Nader; Ghassemi, Mojtaba; Madadi, Alireza

    2014-01-01

    The purpose of this study is to explore any possible difference among the verb types chosen in articles written in English by the non-natives and natives. In so doing, Halliday's Systemic Functional Grammar (1994) was employed. 80 published articles from the medical sciences field of study were chosen from among which 40 were written by native…

  12. Comparing the incomparable: hemodialysis versus peritoneal dialysis in observational studies.

    PubMed

    Foley, Robert N

    2004-01-01

    A randomized trial comparing survival in hemodialysis and peritoneal dialysis remains a utopian aspiration. Dialysis is still relatively rare on a population basis, and a natural tension exists between desirability and feasibility in terms of quality of evidence. In practice, it is very difficult to perform prospective comparisons with large groups of contemporary representative subjects, and much of the literature comes from retrospective national registries. This article considers several questions to address when trying to compare the outcomes of peritoneal dialysis and hemodialysis. Prognostic similarity at baseline is a fundamental issue. Traditionally, adjustment for known prognostic factors has been used in an attempt to minimize the bias caused by nonrandom treatment assignment. Propensity scores have been suggested to be superior, and matched-case analysis may also be a useful method for comparison. Other questions include, when, in relation to starting dialysis, to start the observation clock; the definition and handling of switches of dialysis therapy; and the decision to censor at transplantation. Finally, comparisons are complicated by hazards ratios that vary over time, and time-segmented analysis is obligatory. Many types of analytical approaches are needed to begin to appreciate outcome disparities between dialysis therapies.

  13. Comparative Study on Various Authentication Protocols in Wireless Sensor Networks

    PubMed Central

    Rajeswari, S. Raja; Seenivasagam, V.

    2016-01-01

    Wireless sensor networks (WSNs) consist of lightweight devices with low cost, low power, and short-ranged wireless communication. The sensors can communicate with each other to form a network. In WSNs, broadcast transmission is widely used along with the maximum usage of wireless networks and their applications. Hence, it has become crucial to authenticate broadcast messages. Key management is also an active research topic in WSNs. Several key management schemes have been introduced, and their benefits are not recognized in a specific WSN application. Security services are vital for ensuring the integrity, authenticity, and confidentiality of the critical information. Therefore, the authentication mechanisms are required to support these security services and to be resilient to distinct attacks. Various authentication protocols such as key management protocols, lightweight authentication protocols, and broadcast authentication protocols are compared and analyzed for all secure transmission applications. The major goal of this survey is to compare and find out the appropriate protocol for further research. Moreover, the comparisons between various authentication techniques are also illustrated. PMID:26881272

  14. Beyond EUV lithography: a comparative study of efficient photoresists' performance

    PubMed Central

    Mojarad, Nassir; Gobrecht, Jens; Ekinci, Yasin

    2015-01-01

    Extreme ultraviolet (EUV) lithography at 13.5 nm is the main candidate for patterning integrated circuits and reaching sub-10-nm resolution within the next decade. Should photon-based lithography still be used for patterning smaller feature sizes, beyond EUV (BEUV) lithography at 6.x nm wavelength is an option that could potentially meet the rigid demands of the semiconductor industry. We demonstrate simultaneous characterization of the resolution, line-edge roughness, and sensitivity of distinct photoresists at BEUV and compare their properties when exposed to EUV under the same conditions. By using interference lithography at these wavelengths, we show the possibility for patterning beyond 22 nm resolution and characterize the impact of using higher energy photons on the line-edge roughness and exposure latitude. We observe high sensitivity of the photoresist performance on its chemical content and compare their overall performance using the Z-parameter criterion. Interestingly, inorganic photoresists have much better performance at BEUV, while organic chemically-amplified photoresists would need serious adaptations for being used at such wavelength. Our results have immediate implications for deeper understanding of the radiation chemistry of novel photoresists at the EUV and soft X-ray spectra. PMID:25783209

  15. Complications After Laparoscopic and Conventional Cholecystectomy: A Comparative Study

    PubMed Central

    Brune, Iris B.; Schönleben, K.; Omran, S.

    1994-01-01

    The growing popularity of laparoscopic cholecystectomy (LC) has made extensive series comparing laparoscopic and conventional cholecystectomy in a prospective, randomized way nearly impossible. To evaluate LC we compared retrospectively 800 laparoscopic with 748 conventional cholecystectomies (CC). Of the 800 LC, 10 (1.2%) were converted to laparotomy. 6 conversions were related to aberrant anatomical features or features making dissection very difficult, 4 conversions were due to complications. There were 5 (0, 6%) intraoperative complications during LC and 4 (0.5%) during CC. Postoperative morbidity was 2.1% (n = 17) after LC and 3.7% (n = 28) after CC. Particularly the incidence of wound problems was only 0.5% (n = 4) after LC while it was 1.3% (n = 10) after CC. Overall morbidity was 2.7% (n = 22) for LC and 4.2% (n = 32) for CC. Mortality rate after CC was 0.4% (n = 3), there were no deaths after LC. Common bile duct-injury rate was 0.2% (n = 2) for both groups. Complication rates after LC have been rapidly decreasing with growing experience. Laparoscopic cholecystectomy can safely be performed by appropriately trained surgeons in more than 90% of patients suffering from gallbladder disease. The low morbidity and mortality together with the significant advantages to patient recovery makes laparoscopic cholecystectomy the treatment of choice for symptomatic cholecystolithiasis. PMID:7993860

  16. A comparative study of five different PIV interrogation algorithms

    NASA Astrophysics Data System (ADS)

    Piirto, M.; Eloranta, H.; Saarenrinne, P.; Karvinen, R.

    2005-09-01

    Five different particle image velocimetry (PIV) interrogation algorithms are tested with numerically generated particle images and two real data sets measured in turbulent flows with relatively small particle images of size 1.0 2.5 pixels. The size distribution of the particle images is analyzed for both the synthetic and the real data in order to evaluate the tendency for peak-locking occurrence. First, the accuracy of the algorithms in terms of mean bias and rms error is compared to simulated data. Then, the algorithms’ ability to handle the peak-locking effect in an accelerating flow through a 2:1 contraction is compared, and their ability to estimate the rms and Reynolds shear stress profiles in a near-wall region of a turbulent boundary layer (TBL) at Reτ=510 is analyzed. The results of the latter case are compared to direct numerical simulation (DNS) data of a TBL. The algorithms are: standard fast Fourier transform cross-correlation (FFT-CC), direct normalized cross-correlation (DNCC), iterative FFT-CC with discrete window shift (DWS), iterative FFT-CC with continuous window shift (CWS), and iterative FFT-CC CWS with image deformation (CWD). Gaussian three-point peak fitting for sub-pixel estimation is used in all the algorithms. According to the tests with the non-deformation algorithms, DNCC seems to give the best rms estimation by the wall, and the CWS methods give slightly smaller peak-locking observations than the other methods. With the CWS methods, a bias error compensation method for the bilinear image interpolation, based on the particle image size analysis, is developed and tested, giving the same performance as the image interpolation based on the cardinal function. With the CWD algorithms, the effect of the spatial filter size between the iteration loops is analyzed, and it is found to have a strong effect on the results. In the near-wall region, the turbulence intensity varies by up to 4%, depending on the chosen interrogation algorithm. In

  17. Communication and Culture: The Value of Comparative Studies.

    ERIC Educational Resources Information Center

    Edelstein, Alex S.

    1983-01-01

    Examines cross-cultural studies of news coverage, values and images, and journalistic standards. Suggests that the value of searching for commonalities lies in extending the knowledge of human behavior. (PD)

  18. Assessing Holland Types on the Internet: A Comparative Study

    ERIC Educational Resources Information Center

    Miller, Mark J.; Cowger, Ernest, Jr.; Young, Tony; Tobacyk, Jerome; Sheets, Tillman; Loftus, Christina

    2008-01-01

    This study examined the degree of similarity between scores on the Self-Directed Search and an online instrument measuring Holland types. A relatively high congruency score was found between the two measures. Implications for career counselors are discussed.

  19. A comparative study of SAR data compression schemes

    NASA Technical Reports Server (NTRS)

    Lambert-Nebout, C.; Besson, O.; Massonnet, D.; Rogron, B.

    1994-01-01

    The amount of data collected from spaceborne remote sensing has substantially increased in the last years. During same time period, the ability to store or transmit data has not increased as quickly. At this time, there is a growing interest in developing compression schemes that could provide both higher compression ratios and lower encoding/decoding errors. In the case of the spaceborne Synthetic Aperture Radar (SAR) earth observation system developed by the French Space Agency (CNES), the volume of data to be processed will exceed both the on-board storage capacities and the telecommunication link. The objective of this paper is twofold: to present various compression schemes adapted to SAR data; and to define a set of evaluation criteria and compare the algorithms on SAR data. In this paper, we review two classical methods of SAR data compression and propose novel approaches based on Fourier Transforms and spectrum coding.

  20. [Comparative study of immunomodulating properties of phenibut and gammoxin].

    PubMed

    Tiurenkov, I N; Samotrueva, M A; Kuleshevskaia, N R; Berestovitskaia, V M; Vasil'eva, O S

    2010-12-01

    Experiments on CBA mice with model immunodepression induced by cyclophosphamide showed that phenibut (25 mg/kg) and gammoxin (25 mg/kg) recover both cellular and humoral immunoreactivity and restore lymphoproliferative processes in immunocompetent organs, which is evidence for pronounced immunocorrecting properties of these drugs. A comparative analysis of the immunomodulating activity of phenibut and gammoxin showed that the latter drug predominantly affects the process of immunocompetent cell maturation (growth in mass and cellularity of thymus and spleen--the central immunocompetent organs), while phenibut mostly influences the realization of the final reaction of the primary anti-erythrocyte immune response (significant correction of local infiltration delayed-type hypersensitivity reaction and antibody formation). This difference can be related to the fact that the drugs influence GABA receptors of different types, whereby gammoxin acts on these receptors in immunocompetent organs and phenibut acts on the receptors in lymphocytes.

  1. FLAGdb(++): A Bioinformatic Environment to Study and Compare Plant Genomes.

    PubMed

    Tamby, Jean Philippe; Brunaud, Véronique

    2017-01-01

    Today, the growing knowledge and data accumulation on plant genomes do not solve in a simple way the task of gene function inference. Because data of different types are coming from various sources, we need to integrate and analyze them to help biologists in this task. We created FLAGdb(++) ( http://tools.ips2.u-psud.fr/FLAGdb ) to take up this challenge for a selection of plant genomes. In order to enrich gene function predictions, structural and functional annotations of the genomes are explored to generate meta-data and to compare them. Since data are numerous and complex, we focused on accessibility and visualization with an original and user-friendly interface. In this chapter we present the main tools of FLAGdb(++) and a use-case to explore a gene family: structural and functional properties of this family and research of orthologous genes in the other plant genomes.

  2. A Comparative Study of Failure with Incremental Forming

    NASA Astrophysics Data System (ADS)

    Wu, S. H.; Song, N. N.; Pires, F. M. Andrade

    2016-08-01

    Incremental forming (ISF) is an innovative flexible sheet metal forming process which can be used to manufacture complex shapes from various materials. Due to its flexibility, it has attracted more and more attention over recent decades. Localized deformation and shear through the thickness are essential characteristics of ISF. These lead to specific failure modes and formability of ISF that are different from the conventional stamping process. In this contribution, three continuum damage models (Lemaitre, Gurson, extended GTN models) are formulated and fully coupled with the finite element simulation in a commercial software ABAQUS to predict failure in incremental forming. A comparative investigation of these three damage models has been carried out to analyze both the deformation behavior and failure mechanisms.

  3. Comparative Study of Ten Bacteriocins of Clostridium perfringens

    PubMed Central

    Mahony, D. E.; Li, A.

    1978-01-01

    Bacteriocins of Clostridium perfringens were prepared by ammonium sulfate precipitation of supernatant broth from 10 bacteriocinogenic strains. These bacteriocins were compared with respect to their ability to produce spheroplasts in a sensitive indicator strain; their inducibility; sensitivity to pH, proteolytic enzymes, and boiling; and their effect on macromolecular synthesis. Two bacteriocins were stable over a wide range of pH values and resisted boiling, and three bacteriocins were resistant to trypsin. Five bacteriocins shut down DNA, RNA, and protein synthesis; three bacteriocins had varying effects on DNA and RNA synthesis; and two bacteriocins had little effect on macromolecular synthesis. Antiserum prepared against one bacteriocin highly neutralized three bacteriocins with partial neutralization of five others; two bacteriocins were unaffected. Mutant strains selected for resistance to bacteriocin 28 also demonstrated coresistance to two other closely related bacteriocins and partial resistance to five others. PMID:217302

  4. Comparative Study of Alkaloid Pattern of Four Bulgarian Fumaria species.

    PubMed

    Doncheva, Tsvetelina; Yordanova, Gabriela; Vutov, Vassil; Kostova, Nadezhda; Philipov, Stefan

    2016-02-01

    The alkaloid pattern of four Fumaria species (Fumaria kralikii, Fumaria rostellata, Fumaria schleicherii, Fumaria thureii) growing in Bulgaria was investigated by GC-MS and twenty isoquinoline alkaloids were determined. Phytochemical investigation of the alkaloid composition on Fumaria thuretii Boiss was made for the first time. The alkaloid profile of the species was compared at two levels, between different species and within two species from different habitats. Two chemotypical groups, based on the types of isoquinoline alkaloids were suggested. To group A belong species F. kralikii, F. rostellata (F. r. 1) and F. thuretii containing more than 50% spirobenzylisoquinoline alkaloids of the crude alkaloid mixtures. To group B belong species F. rostellata (F. r. 2) and F. schleicherii containing more than 40% protopine alkaloids and relatively high percentage phthaldeisoquinoline alkaloids (11-19%). In group A phthaldeisoquinoline alkaloids were not detected.

  5. A comparative study of computational methods in cosmic gas dynamics

    NASA Technical Reports Server (NTRS)

    Van Albada, G. D.; Van Leer, B.; Roberts, W. W., Jr.

    1982-01-01

    Many theoretical investigations of fluid flows in astrophysics require extensive numerical calculations. The selection of an appropriate computational method is, therefore, important for the astronomer who has to solve an astrophysical flow problem. The present investigation has the objective to provide an informational basis for such a selection by comparing a variety of numerical methods with the aid of a test problem. The test problem involves a simple, one-dimensional model of the gas flow in a spiral galaxy. The numerical methods considered include the beam scheme, Godunov's method (G), the second-order flux-splitting method (FS2), MacCormack's method, and the flux corrected transport methods of Boris and Book (1973). It is found that the best second-order method (FS2) outperforms the best first-order method (G) by a huge margin.

  6. Comparative Study of the Thermal Conductivity of Solid Biomass Fuels

    PubMed Central

    2016-01-01

    The thermal conductivity of solid biomass fuels is useful information in the investigation of biomass combustion behavior and the development of modeling especially in the context of large scale power generation. There are little published data on the thermal conductivity of certain types of biomass such as wheat straw, miscanthus, and torrefied woods. Much published data on wood is in the context of bulk materials. A method for determining the thermal conductivities of small particles of biomass fuels has been developed using a custom built test apparatus. Fourteen different samples of various solid biomass fuel were processed to form a homogenized pellet for analysis. The thermal conductivities of the pelletized materials were determined and compared against each other and to existing data. PMID:27041819

  7. A critique of comparative studies of brain size

    PubMed Central

    Healy, Susan D; Rowe, Candy

    2006-01-01

    In recent years, there have been over 50 comparative analyses carried out in which social or ecological variables have been used to explain variation in whole brain size, or a part thereof, in a range of vertebrate species. Here, we review this body of work, pointing out that there are a number of substantial problems with some of the assumptions that underpin the hypotheses (e.g. what brain size means), with the data collection and with the ways in which the data are combined in the analyses. These problems are particularly apparent in those analyses in which attempts are made to correlate complex behaviour with parts of the brain that carry out multiple functions. We conclude that now is the time to substantiate these results with data from experimental manipulations. PMID:17476764

  8. Comparative study of ion conducting pathways in borate glasses

    SciTech Connect

    Hall, Andreas; Swenson, Jan; Adams, Stefan

    2006-11-01

    The conduction pathways in metal-halide doped silver, lithium, and sodium diborate glasses have been examined by bond valence analysis of reverse Monte Carlo (RMC) produced structural models of the glasses. Although all glass compositions have basically the same short-range structure of the boron-oxygen network, it is evident that the intermediate-range structure is strongly dependent on the type of mobile ion. The topography of the pathways and the coordination of the pathway sites differ distinctly between the three glass systems. The mobile silver ions in the AgI-doped glass tend to be mainly iodine-coordinated and travel in homogeneously distributed pathways located in salt-rich channels of the borate network. In the NaCl-doped glass, there is an inhomogeneous spatial distribution of pathways that reflects the inhomogeneous introduction of salt ions into the glass. However, since the salt clusters are not connected, no long-range conduction pathways are formed without including also oxygen-rich regions. The pathways in the LiCl-doped glass are slightly more evenly distributed compared to the NaCl-doped glass (but not as ordered as in the AgI-doped glass), and the regions of mainly oxygen-coordinated pathway sites are of higher importance for the long-range migration. In order to more accurately investigate how these differences in the intermediate-range order of the glasses affect the ionic conductivity, we have compared the realistic structure models to more or less randomized structures. An important conclusion from this comparison is that we find no evidence that a pronounced intermediate-range order in the atomic structure or in the network of conduction pathways, as in the AgI-doped glass, is beneficial for the dc conductivity.

  9. Priority Questions and Horizon Scanning for Conservation: A Comparative Study

    PubMed Central

    Kark, Salit; Sutherland, William J.; Shanas, Uri; Klass, Keren; Achisar, Hila; Dayan, Tamar; Gavrieli, Yael; Justo-Hanani, Ronit; Mandelik, Yael; Orion, Nir; Pargament, David; Portman, Michelle; Reisman-Berman, Orna; Safriel, Uriel N.; Schaffer, Gad; Steiner, Noa; Tauber, Israel; Levin, Noam

    2016-01-01

    Several projects aimed at identifying priority issues for conservation with high relevance to policy have recently been completed in several countries. Two major types of projects have been undertaken, aimed at identifying (i) policy-relevant questions most imperative to conservation and (ii) horizon scanning topics, defined as emerging issues that are expected to have substantial implications for biodiversity conservation and policy in the future. Here, we provide the first overview of the outcomes of biodiversity and conservation-oriented projects recently completed around the world using this framework. We also include the results of the first questions and horizon scanning project completed for a Mediterranean country. Overall, the outcomes of the different projects undertaken (at the global scale, in the UK, US, Canada, Switzerland and in Israel) were strongly correlated in terms of the proportion of questions and/or horizon scanning topics selected when comparing different topic areas. However, some major differences were found across regions. There was large variation among regions in the percentage of proactive (i.e. action and response oriented) versus descriptive (non-response oriented) priority questions and in the emphasis given to socio-political issues. Substantial differences were also found when comparing outcomes of priority questions versus horizon scanning projects undertaken for the same region. For example, issues related to climate change, human demography and marine ecosystems received higher priority as horizon scanning topics, while ecosystem services were more emphasized as current priority questions. We suggest that future initiatives aimed at identifying priority conservation questions and horizon scanning topics should allow simultaneous identification of both current and future priority issues, as presented here for the first time. We propose that further emphasis on social-political issues should be explicitly integrated into future

  10. Priority Questions and Horizon Scanning for Conservation: A Comparative Study.

    PubMed

    Kark, Salit; Sutherland, William J; Shanas, Uri; Klass, Keren; Achisar, Hila; Dayan, Tamar; Gavrieli, Yael; Justo-Hanani, Ronit; Mandelik, Yael; Orion, Nir; Pargament, David; Portman, Michelle; Reisman-Berman, Orna; Safriel, Uriel N; Schaffer, Gad; Steiner, Noa; Tauber, Israel; Levin, Noam

    2016-01-01

    Several projects aimed at identifying priority issues for conservation with high relevance to policy have recently been completed in several countries. Two major types of projects have been undertaken, aimed at identifying (i) policy-relevant questions most imperative to conservation and (ii) horizon scanning topics, defined as emerging issues that are expected to have substantial implications for biodiversity conservation and policy in the future. Here, we provide the first overview of the outcomes of biodiversity and conservation-oriented projects recently completed around the world using this framework. We also include the results of the first questions and horizon scanning project completed for a Mediterranean country. Overall, the outcomes of the different projects undertaken (at the global scale, in the UK, US, Canada, Switzerland and in Israel) were strongly correlated in terms of the proportion of questions and/or horizon scanning topics selected when comparing different topic areas. However, some major differences were found across regions. There was large variation among regions in the percentage of proactive (i.e. action and response oriented) versus descriptive (non-response oriented) priority questions and in the emphasis given to socio-political issues. Substantial differences were also found when comparing outcomes of priority questions versus horizon scanning projects undertaken for the same region. For example, issues related to climate change, human demography and marine ecosystems received higher priority as horizon scanning topics, while ecosystem services were more emphasized as current priority questions. We suggest that future initiatives aimed at identifying priority conservation questions and horizon scanning topics should allow simultaneous identification of both current and future priority issues, as presented here for the first time. We propose that further emphasis on social-political issues should be explicitly integrated into future

  11. Study on Lexical Cohesion in English and Persian Research Articles (A Comparative Study)

    ERIC Educational Resources Information Center

    Mirzapour, Fatemeh; Ahmadi, Maryam

    2011-01-01

    The present study aims to analyze comparatively English and Persian research articles (Linguistics, Literature, and Library and Information disciplines) in terms of number and degree of utilization of sub-types of lexical cohesion in order to appreciate textualization processes in the two languages concerned. The study analyzes 60 research…

  12. Oral Mucocutaneous Lesions – A Comparative Clinicopathological and Immunofluorescence Study

    PubMed Central

    Rameshkumar, Annasamy; Varghese, Alex Kumaranthara; Dineshkumar, Thayalan; Ahmed, Shaheen; Venkatramani, Janaki; Sugirtharaj, G

    2015-01-01

    Background: Oral mucosa is often affected by many diseases including mucocutaneous disorders. The diagnoses of these disorders are primarily based on history, clinical features, and histopathology. For the past few years’ immunofluorescence techniques emerged as an important tool to study the pathogenesis and in the diagnosis of oral mucocutaneous and vesiculobullous disorders. The present study was designed to carry out retrospective and prospective analysis of oral mucocutaneous lesions to elucidate the clinicopathologic features and its immunofluorescence findings. Materials and Methods: A total of 70 subjects with oral mucocutaneous lesions were retrieved from the oral pathology files of Tamil Nadu Govt. Dental College and their clinical features were evaluated, and the histopathology was also evaluated with the help of hematoxylin and eosin stained sections. For the prospective study, biopsy from 12 subjects with oral mucocutaneous lesions was subjected to routine histopathological examination and DIF to evaluate the consistency of the methods. Results: In the retrospective analysis of 70 subjects with oral mucocutaneous lesions in relation to clinical features and histopathology, most of the findings were similar to the previous studies except for few criteria like male predilection in lichen planus and mucous membrane pemphigoid (MMP) and more prevalence of pemphigus vulgaris than MMP (2:1). In the prospective analysis of 12 subjects, the histopathological diagnosis was consistent with DIF study in 66% of cases. Conclusion: The diagnostic efficiency of oral mucocutaneous lesions can be improved by modern tools like DIF studies in addition to traditional methods like clinical and histopathology. PMID:25878481

  13. A comparative study of expectant parents ' childbirth expectations.

    PubMed

    Kao, Bi-Chin; Gau, Meei-Ling; Wu, Shian-Feng; Kuo, Bih-Jaw; Lee, Tsorng-Yeh

    2004-09-01

    The purpose of this study was to understand childbirth expectations and differences in childbirth expectations among expectant parents. For convenience sampling, 200 couples willing to participate in this study were chosen from two hospitals in central Taiwan. Inclusion criteria were at least 36 weeks of gestation, aged 18 and above, no prenatal complications, and willing to consent to participate in this study. Instruments used to collect data included basic demographic data and the Childbirth Expectations Questionnaire. Findings of the study revealed that (1) five factors were identified by expectant parents regarding childbirth expectations including the caregiving environment, expectation of labor pain, spousal support, control and participation, and medical and nursing support; (2) no general differences were identified in the childbirth expectations between expectant fathers and expectant mothers; and (3) expectant fathers with a higher socioeconomic status and who had received prenatal (childbirth) education had higher childbirth expectations, whereas mothers displayed no differences in demographic characteristics. The study results may help clinical healthcare providers better understand differences in expectations during labor and birth and childbirth expectations by expectant parents in order to improve the medical and nursing system and promote positive childbirth experiences and satisfaction for expectant parents.

  14. Decontamination Methods Used for Dental Burs – A Comparative Study

    PubMed Central

    Hugar, Deepa; Hugar, Santosh; Ranjan, Shashi; Kadani, Megha

    2014-01-01

    Aims and Objectives: Infection control and modes of sterilizations are the key factors to avoid cross transmission of infection in the field of dentistry. Transmission of disease or infection is noted with improper sterilization of reused instruments. Dental burs are the most important tool in any endodontic or conservative procedures of teeth involving tooth contouring, restorative filling procedures and endodontic procedures. Hence, the present study is undertaken to assess the efficacy of different methods of sterilization or decontamination which are routinely used in dental clinics. Materials and Methods: For the present study 96 round diamond burs were selected and divided into 6 groups. These burs were used for the access cavity preparation to get contamination and subjected for bacteriological culture. After getting base line date burs were subjected to manual scrubbing, hot air oven, glass bead sterilizer, ultrasonic cleaner and autoclave to get post decontamination data. Results: The study revealed that mean colony forming units/ml of Streptococcus mutans decreased maximum for autoclave with 80% reduction, for Lactobacilli 76% reduction and for Candida albicans maximum reduction seen for glass bead sterilizer with 74%. Conclusion: Findings of our study revealed that none of the methods used were found to be absolutely efficacious in the decontamination of dental burs. However, among the experimental groups used in the present study, autoclave was found to be the relatively best method. PMID:25121062

  15. A comparative study of endoscopic septoplasty versus conventional septoplasty.

    PubMed

    Sathyaki, D C; Geetha, Chary; Munishwara, G B; Mohan, M; Manjuanth, K

    2014-06-01

    Nasal obstruction due to deviated nasal septum is a common problem encountered by otolaryngologists. A variety of surgical procedures have been tried in the treatment of the same. This study was conducted to evaluate the outcomes and complications of endoscopic and conventional septoplasty. This is a prospective, randomized study. Fifty patients with symptomatic deviated nasal septum were included in the study, 25 of them underwent conventional septoplasty and the rest underwent endoscopic septoplasty. The difference in the functional outcome of both the surgeries was insignificant. There was a significant difference with respect to complications. Endoscopic septoplasty had better outcome with respect to complications. It is easier to correct posterior deviations and isolated spurs with endoscopic septoplasty. Complications are lesser with endoscopic septoplasty.

  16. A Comparative Study of Aerocapture Missions with a Mars Destination

    NASA Technical Reports Server (NTRS)

    Vaughan, Diane; Miller, Heather C.; Griffin, Brand; James, Bonnie F.; Munk, Michelle M.

    2005-01-01

    Conventional interplanetary spacecraft use propulsive systems to decelerate into orbit. Aerocapture is an alternative approach for orbit capture, in which the spacecraft makes a single pass through a target destination's atmosphere. Although this technique has never been performed, studies show there are substantial benefits of using aerocapture for reduction of propellant mass, spacecraft size, and mission cost. The In-Space Propulsion (ISP) Program, part of NASA's Science Mission Directorate, has invested in aerocapture technology development since 2002. Aerocapture investments within ISP are largely driven by mission systems analysis studies, The purpose of this NASA-funded report is to identify and document the fundamental parameters of aerocapture within previous human and robotic Mars mission studies which will assist the community in identifying technology research gaps in human and robotic missions, and provide insight for future technology investments. Upon examination of the final data set, some key attributes within the aerocapture disciplines are identified.

  17. Comparative study of clinical grade human tolerogenic dendritic cells

    PubMed Central

    2011-01-01

    Background The use of tolerogenic DCs is a promising therapeutic strategy for transplantation and autoimmune disorders. Immunomodulatory DCs are primarily generated from monocytes (MDDCs) for in vitro experiments following protocols that fail to fulfil the strict regulatory rules of clinically applicable products. Here, we compared the efficacy of three different tolerance-inducing agents, dexamethasone, rapamycin and vitamin D3, on DC biology using GMP (Good Manufacturing Practice) or clinical grade reagents with the aim of defining their use for human cell therapy. Methods Tolerogenic MDDCs were generated by adding tolerogenic agents prior to the induction of maturation using TNF-α, IL-β and PGE2. We evaluated the effects of each agent on viability, efficiency of differentiation, phenotype, cytokine secretion and stability, the stimulatory capacity of tol-DCs and the T-cell profiles induced. Results Differences relevant to therapeutic applicability were observed with the cellular products that were obtained. VitD3-induced tol-DCs exhibited a slightly reduced viability and yield compared to Dexa-and Rapa-tol-DCs. Phenotypically, while Dexa-and VitD3-tol-DCs were similar to immature DCs, Rapa-tol-DCs were not distinguishable from mature DCs. In addition, only Dexa-and moderately VitD3-tol-DCs exhibited IL-10 production. Interestingly, in all cases, the cytokine secretion profiles of tol-DCs were not modified by a subsequent TLR stimulation with LPS, indicating that all products had stable phenotypes. Functionally, clearly reduced alloantigen T cell proliferation was induced by tol-DCs obtained using any of these agent. Also, total interferon-gamma (IFN-γ) secretion by T cells stimulated with allogeneic tol-DCs was reduced in all three cases, but only T cells co-cultured with Rapa-tol-DCs showed impaired intracellular IFN-γ production. In addition, Rapa-DCs promoted CD4+ CD127 low/negative CD25high and Foxp3+ T cells. Conclusions Our results demonstrate

  18. Automated Versus Conventional Systematic Desensitization: A Study of Comparative Effectiveness.

    ERIC Educational Resources Information Center

    De Csipkes, Robert A.; Rowe, Wayne

    This study investigates whether variations in method of presentation of anxiety items (experimenter's voice, experimenter's taped voice, subject's taped voice) will result in differences in autonomic arousal (as measured by self-report, galvanic skin response, cardiac rate, blood pressure). Ss were 24 Naval Academy midshipmen. The procedure…

  19. Five Teaching Methods: A Comparative Study in Nurse Education

    ERIC Educational Resources Information Center

    Tibbitts, George E.; And Others

    1978-01-01

    The relative instructional effectiveness of five teaching methods, Reading, Lecture-traditional, Lecture-audiotape, Programmed Instruction and Multimedia, was studied. Comparisons were based on test scores obtained by trainee nurses on three different occasions following instruction on a topic in renal physiology. (Editor)

  20. Undergraduate Knowledge of Aging: A Comparative Study of Biopsychosocial Content

    ERIC Educational Resources Information Center

    Damron-Rodriguez, JoAnn; Funderburk, Brooke; Lee, Martin; Solomon, David H.

    2004-01-01

    This study assesses undergraduate knowledge of aging, distinguishing between types of deficits (ignorance vs. misinformation) and content areas as delineated by a biopsychosocial framework. Knowledge is examined as an outcome of taking an aging elective, while accounting for course rating and knowledge retention. A diverse body of UCLA…

  1. A Comparative Study of Academic Versus Business Sabbaticals

    ERIC Educational Resources Information Center

    Joseph, Gilbert W.; Kucera, Stephen D.

    2004-01-01

    The first academic sabbatical was introduced at Harvard in 1880. In recent years, commercial enterprises have also identified workplace benefit programs as "sabbaticals." Benshoff and Spruill (2002), whose own study investigated the success of sabbaticals for counseling professors, also indicate an increased interest in the sabbatical's potential…

  2. Governance Paradigms of Public Universities: An International Comparative Study

    ERIC Educational Resources Information Center

    Christopher, Joe

    2012-01-01

    This study aims to develop a conceptual model of the wider influencing forces impacting the governance paradigms of public universities. It draws on the multi-theoretical governance concept and seeks to identify these forces through the lens of chief audit executives using a qualitative research approach. The interview data supported by published…

  3. E-Learning System's Acceptance: A Comparative Study

    ERIC Educational Resources Information Center

    Abu-Shanab, Emad

    2014-01-01

    The major limitation for adopting e-learning systems is students and teachers perceptions of such applications. EduWave is a system implemented in Jordan, to be used by teachers, students and other stakeholders in public schools in the country. This study tried to contrast the perceptions of students and teachers and conclude to future agenda for…

  4. Grandparents Raising Their Grandchildren: A Comparative Study of Depression

    ERIC Educational Resources Information Center

    Strutton, Joan N.

    2010-01-01

    There has been a steady increase in the United States in recent decades of grandparents raising their grandchildren. The aim of this study was to determine if depression levels of grandparents raising their grandchildren and depression levels of traditional grandparents differ. Additionally, the extent of the relationship to depression scores by…

  5. Operations: A Comparative Study of the United States and Taiwan

    ERIC Educational Resources Information Center

    Lin, Cheng-Yao; Becker, Jerry; Byun, Mi-Ran; Yang, Der-Ching; Huang, Tsai-Wei

    2013-01-01

    This study examined (a) the differences in preservice teachers’ procedural knowledge in four areas of fraction operations in Taiwan and the United States, (b) the differences in preservice teachers’ conceptual knowledge in four areas of fraction operations in Taiwan and the United States, and (c) correlation in preservice teachers’ conceptual…

  6. A Comparative Study of Three Revision Methods in EFL Writing

    ERIC Educational Resources Information Center

    Srichanyachon, Napaporn

    2011-01-01

    In an attempt to explore effective instruction in the English as a Foreign Language (EFL) setting, this study investigated language errors identified by students and teachers in three different revision stages: self-revision, peer revision, and teacher revision. It gave the focus to the effects of the three different methods on learners' writing…

  7. Education in Germany since Unification. Oxford Studies in Comparative Education.

    ERIC Educational Resources Information Center

    Phillips, David, Ed.

    This collection of papers discusses issues related to education in Germany since its unification. The papers include: "The Legacy of Unification" (David Phillips); "Change and Continuity in Education After the 'Wende'" (E. J. Neather); "A Study of Teachers' Perceptions in Brandenburg 'Gesamtschulen'" (Stephanie…

  8. A Comparative Study of Science, Systems Analysis and Futurism

    ERIC Educational Resources Information Center

    Correa, Hector

    1975-01-01

    The proper framework for studying different methods of problem-solving is to recognize that there are different approaches to the analysis of reality. Three approaches--science, systems analysis, and futurism--are considered within the framework of the "theory of knowledge." (Author/IRT)

  9. Adolescent Literacy and School Structure: A Comparative Case Study

    ERIC Educational Resources Information Center

    Codispoti, Marie

    2010-01-01

    Students who leave elementary school after fourth grade may not be receiving adequate literacy instruction. Although many recent studies have focused on a drop in test scores for middle school students, a gap exists in the literature with regard to explicit literacy instruction in elementary and non-elementary school settings. To inform educators…

  10. A comparative breastfeeding study in two contrasting areas.

    PubMed

    Buckell, M; Thompson, R

    1995-02-01

    An apparent decline in breastfeeding rates motivated health visiting staff within Hillingdon Community Health Trust to undertake a research project on infant feeding practice. Margaret Buckell and Rosemary Thompson describe a study to measure intent to breastfeed, breastfeeding initiation rates and feeding outcomes in two contrasting areas of Hillingdon, an outer London borough, and to identify areas for further work to improve breastfeeding levels.

  11. Offenders with Intellectual Disability: A Prospective Comparative Study

    ERIC Educational Resources Information Center

    Barron, P.; Hassiotis, A.; Banes, J.

    2004-01-01

    Intellectually disabled offenders (IDO) are a poorly served and under-recognized group, who are likely to require long-term specialist treatments and interventions. Method This prospective study investigated the characteristics and factors that influence outcome in this group, with particular reference to therapeutic interventions. Sixty-one…

  12. Age and Workers' Perceptions of Workplace Safety: A Comparative Study

    ERIC Educational Resources Information Center

    Gyekye, Seth Ayim; Salminen, Simo

    2009-01-01

    The study examined the relationship between age and I) safety perception; ii) job satisfaction; iii) compliance with safety management policies; and (iv) accident frequency. Participants were Ghanaian industrial workers (N = 320) categorized into 4 age groups: 19-29 years; 30-39 years; 40-50 years; and 51 years and above. Workplace safety…

  13. The Comparative Studying of Rumi and Bonaventura Mystical Epistemology

    ERIC Educational Resources Information Center

    Aliyari, Farshad; Elmi, Qorban; Alizamani, Amirabbas

    2016-01-01

    The purpose of this paper is to consider most critical issues of mystical epistemology in Rumi and Bonaventura once the views on subject, reality of the world, and the possibility of knowledge were expressed. This research referring works of Rumi and Bonaventura studies this issue through a descriptive-analytical method. Rumi and Bonaventura…

  14. Entering Student Affairs: A Comparative Study of Graduate School Choice

    ERIC Educational Resources Information Center

    Mertz, Norma; Eckman, Ellen; Strayhorn, Terrell

    2012-01-01

    This article describes the college choice process of graduate students in College Student Personnel programs at a public university and a private religiously affiliated university. Despite differences in size, mission, and location of the two institutions studied, the research findings show that respondent populations were similar demographically…

  15. Library Abuse in Academic Institutions: A Comparative Study.

    ERIC Educational Resources Information Center

    Obiagwu, Marcel C.

    1992-01-01

    Describes a study that investigated the abuse of library materials through theft, mutilation, unauthorized borrowing, and vandalism at the University of Port Harcourt (Nigeria) and King Fahd University of Petroleum and Minerals (Saudi Arabia). Motivations for abuse are discussed, and recommendations for improved collection protection are…

  16. Comparative study of switchgrass cultivars using RNA sequencing technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Switchgrass (Panicum virgatum L.) is a C4 perennial grass, identified as a promising bioenergy crop. Switchgrass exists in two ecotypes, upland and lowland, which are heterotic, or genetically complementary to each other. The objectives of this study are to assess the potential of SNP markers as a b...

  17. Workplace Discrimination and Americans with Psychiatric Disabilities: A Comparative Study

    ERIC Educational Resources Information Center

    An, Sunghee; Roessler, Richard T.; McMahon, Brian T.

    2011-01-01

    This study reports findings from an analysis of employment allegations and resolutions maintained in the U.S. Equal Employment Opportunity Commission (EEOC) database. Spanning the years 1992 to 2005, the data were aggregated for individuals with psychiatric disabilities and individuals with a variety of physical, sensory, and neurological…

  18. A comparative study of measurements from radiosondes, rocketsondes, and satellites

    NASA Technical Reports Server (NTRS)

    Nestler, M. S.

    1983-01-01

    Direct comparisons of operational products derived from measurements of radiance by satellites to measurements from conventional in situ sensors are important for the evaluation of satellite systems. However, errors in the in situ measurements themselves complicate such comparisons. Atmospheric temporal and spatial variability are also influential. These issues are investigated by means of a special field program composed of flights of dual radiosondes and multiple radiosondes launched near the time of NOAA-6 overpasses. Satellite derived mean layer temperatures, geopotential heights, and winds are compared with the same quantities determined from the in situ sensors. Of particular interest is the impact of in situ errors on these comparisons. It is shown that the radiosonde provides a precise pressure height relationship and therefore precise data for synoptic type use. Radar tracking of the radiosondes reveals, however, an imprecise pressure measurement which causes large differences between the actual altitude of the radiosonde and the altitude at which it is calculated to be. Radiosondes should be radar tracked and pressures calculated if the data are to be used for purposes other than synoptic use. Evaluation of rocketsonde data reveals a temperature precision of 1 to 2 K below about 55 km. Above 55 km, the precision decreases rapidly; rms differences of up to 11 K are obtained.

  19. Comparative studies of Lunar, Martian, and Mercurian craters and plains

    NASA Technical Reports Server (NTRS)

    Oberbeck, V. R.; Quaide, W. L.; Arvidson, R. E.; Aggarwal, H. R.

    1977-01-01

    Lunar features provide a valuable interpretation data base for comparison with features on other planets which are believed to have been formed by the cratering process. The paper adopts the comparative approach by examining the smooth plains of the moon and Mercury, with special emphasis on crater degradation on the moon, Mercury, and Mars. A possible cause for the observed deficiency of craters with diameters no more than 50 km on certain areas of lunar uplands and on the entire uplands of Mercury and Mars is discussed. It is suggested that pertinent differences can be predicted on the basis of new concepts for production population and of effects of changes in planetary conditions on the secondary cratering process. It is concluded that the deficiency of craters with diameters no more than 50 km on parts of the lunar uplands and on the Mercurian and Martian uplands may be evidence for a deficiency in production of primary craters in this size range. Origin of the late heavy bombardment in the inner solar system is examined.

  20. A Comparative Study of Some Dynamic Stall Models

    NASA Technical Reports Server (NTRS)

    Reddy, T. S. R.; Kaza, K. R. V.

    1987-01-01

    Three semi-empirical aerodynamic stall models are compared with respect to their lift and moment hysteresis loop prediction, limit cycle behavior, easy implementation, and feasibility in developing the parameters required for stall flutter prediction of advanced turbines. For the comparison of aeroelastic response prediction including stall, a typical section model and a plate structural model are considered. The response analysis includes both plunging and pitching motions of the blades. In model A, a correction to the angle of attack is applied when the angle of attack exceeds the static stall angle. In model B, a synthesis procedure is used for angles of attack above static stall angles and the time history effects are accounted through the Wagner function. In both models the life and moment coefficients for angle of attack below stall are obtained from tabular data for a given Mach number and angle of attack. In model C, referred to an the ONERA model, the life and moment coefficients are given in the form of two differential equations, one for angles below stall, and the other for angles above stall. The parameters of those equations are nonlinear functions of the angle of attack.

  1. Refractive results after phacoemulsification and ECCE. A comparative study.

    PubMed

    Dam-Johansen, M; Olsen, T

    1993-06-01

    The refractive results were evaluated in 79 patients undergoing cataract extraction by phacoemulsification using a 6-7 mm tunnel incision, and compared with a group of 77 patients undergoing planned extracapsular cataract extraction (ECCE) by the same surgeon. A mean increase in the keratometric cylinder of 0.05D and 0.52D was found in the phacoemulsification and the extracapsular cataract extraction group, respectively. This was significantly different from zero for the extracapsular cataract extraction group (p < 0.05) but not for the phacoemulsification group (p > 0.05). By vector analysis, the mean surgically induced astigmatism was 0.91D and 1.36D in the phacoemulsification and the extracapsular cataract extraction group, respectively (p < 0.01). The IOL power prediction error (spectacle plane) was found to be 0.17D (+/- 0.69 SD) in the phacoemulsification group and 0.02 D (+/- 0.79 SD) in the extracapsular cataract extraction group, respectively. We conclude that phacoemulsification improves the surgical control of the refractive outcome of cataract surgery.

  2. A Comparative Study Using CFD to Predict Iced Airfoil Aerodynamics

    NASA Technical Reports Server (NTRS)

    Chi, x.; Li, Y.; Chen, H.; Addy, H. E.; Choo, Y. K.; Shih, T. I-P.

    2005-01-01

    WIND, Fluent, and PowerFLOW were used to predict the lift, drag, and moment coefficients of a business-jet airfoil with a rime ice (rough and jagged, but no protruding horns) and with a glaze ice (rough and jagged end has two or more protruding horns) for angles of attack from zero to and after stall. The performance of the following turbulence models were examined by comparing predictions with available experimental data. Spalart-Allmaras (S-A), RNG k-epsilon, shear-stress transport, v(sup 2)-f, and a differential Reynolds stress model with and without non-equilibrium wall functions. For steady RANS simulations, WIND and FLUENT were found to give nearly identical results if the grid about the iced airfoil, the turbulence model, and the order of accuracy of the numerical schemes used are the same. The use of wall functions was found to be acceptable for the rime ice configuration and the flow conditions examined. For rime ice, the S-A model was found to predict accurately until near the stall angle. For glaze ice, the CFD predictions were much less satisfactory for all turbulence models and codes investigated because of the large separated region produced by the horns. For unsteady RANS, WIND and FLUENT did not provide better results. PowerFLOW, based on the Lattice Boltzmann method, gave excellent results for the lift coefficient at and near stall for the rime ice, where the flow is inherently unsteady.

  3. Comparative studies on performance of single cell and PEMFC stack

    NASA Astrophysics Data System (ADS)

    Onggo, Holia; Irmawati, Yuyun; Yudianti, Rike

    2016-02-01

    Single-cell, 2-cell and 3-cell of polymer electrolyte membrane fuel cells (PEMFCs) with an active area of 9 cm2 per cell have been fabricated and characterized its performance and electrochemical properties. The membrane electrode assembly (MEA) was prepared by hot pressing commercial gas diffusion electrodes (Pt loading 0.5 mg/cm2) on pre-treated Nafion 117 membrane. The experimental results are presented as polarization and power output curves which show the effects of varying H2/O2 back pressures on the PEMFC performance. Three varying H2/O2 volumetric flow-rates for three different cell stacks were employed based on the optimal condition to produce good performance of stack. Cell performances for single cell, 2-cell, or 3-cell PEMFCs are slightly comparable with the power output 1.2 - 1.3 W in average. Enhancing back pressure induces increasing performance PEMFCs as indicated by changing the power from 1.19 W (open end) to 1.33W (15 psi).

  4. A comparative study on karyotypic diversification rate in mammals.

    PubMed

    Martinez, P A; Jacobina, U P; Fernandes, R V; Brito, C; Penone, C; Amado, T F; Fonseca, C R; Bidau, C J

    2017-04-01

    Chromosomal rearrangements have a relevant role in organismic evolution. However, little is known about the mechanisms that lead different phylogenetic clades to have different chromosomal rearrangement rates. Here, we investigate the causes behind the wide karyotypic diversity exhibited by mammals. In particular, we analyzed the role of metabolic, reproductive, biogeographic and genomic characteristics on the rates of macro- and microstructural karyotypic diversification (rKD) using comparative phylogenetic methods. We found evidence that reproductive characteristics such as larger litter size per year and longevity, by allowing a higher number of meioses in absolute time, favor a higher probability of chromosomal change. Furthermore, families with large geographic distributions but containing species with restricted geographic ranges showed a greater probability of fixation of macrostructural chromosomal changes in different geographic areas. Finally, rKD does not evolve by Brownian motion because the mutation rate depends on the concerted evolution of repetitive sequences. The decisive factors of rKD evolution will be natural selection, genetic drift and meiotic drive that will eventually allow or not the fixation of the rearrangements. Our results indicate that mammalian karyotypic diversity is influenced by historical and adaptive mechanisms where reproductive and genomic factors modulate the rate of chromosomal change.

  5. A comparative structural study of wet and dried ettringite

    SciTech Connect

    Renaudin, G.; Filinchuk, Y.; Neubauer, J.; Goetz-Neunhoeffer, F.

    2010-03-15

    Two different techniques were used to compare structural characteristics of 'wet' ettringite (stored in the synthesis mother liquid) and 'dried' ettringite (dried to 35% relative humidity over saturated CaCl{sub 2} solution). Lattice parameters and the water content in the channel region of the structure (site occupancy factor of the water molecule not bonded to cations) as well as microstructure parameters (size and strain) were determined from a Rietveld refinement on synchrotron powder diffraction data. Local environment of sulphate anions and of the hydrogen bonding network was characterized by Raman spectroscopy. Both techniques led to the same conclusion: the 'wet' ettringite sample immersed in the mother solution from the synthesis presents similar structural features as ettringite dried to 35% relative humidity. An increase of the a lattice parameter combined with a decrease of the c lattice parameter occurs on drying. The amount of structural water, the point symmetry of sulphate and the hydrogen bond network are unchanged when passing from the wet to the dried ettringite powder. Ettringite does not form a high-hydrate polymorph in equilibrium with alkaline solution, in contrast to the AFm phases that lose water molecules on drying. According to these results we conclude that ettringite precipitated in aqueous solution at the early hydration stages is of the same chemical composition as ettringite present in the hardening concrete.

  6. [Comparative study of concentrated blood derivatives of factor VIII].

    PubMed

    Baklaja, R; Miletić, V; Stajić, M; Cvetković, V; Grozdanić, V

    1984-01-01

    The work presents results of the investigations of blood derivatives--F VIII concentrates: commercial cryoprecipitate, concentrate of intermediary purity and derivatives of high purity: Kriobulin--Immuno, Octobulin--Landerlan, Profilate--Alfa, Factor VIII--Behring, Hemofil--Hyland, Factorate--Armour Pharma, AHF--Kaote Cutter. The following parameters were investigated: VIII: C, VIIIR: Ag, total protein, protein electrophoresis, IgG, IgA and IgM immunoglobulins and anti-A and anti-B isoagglutinins. All derivatives except cyroprecipitate have considerably higher VIIIR: RAg value compared with VIII: C, which indicated inactivation of labile VIII: C component during concentrate preparation. Specific activity varied depending on purity of preparations, but ranged from 1,72 to 22. High isoagglutinin titer of anti-A was noted in preparations of high purity, as well as the presence of immunoglobulins. Despite considerable differences in vitro, all concentrated derivatives F VIII have similar immediate clinical effect and recovery from 0,87 to 1,36. All results indicate that new ways of derivative F VIII purification should be found with lower degree of contamination of other plasma proteins and less risk of hepatitis virus transmission. When certain indications are recognized, cryoprecipitate produced in our country in all blood transfusion services should be used.

  7. Homograft and prosthetic aortic valve replacement: a comparative study.

    PubMed

    Pine, M; Hahn, G; Paton, B; Pappas, G; Davies, H; Steele, P; Pryor, R; Blount, S G

    1976-12-01

    Homograft aortic valve replacement was done in 103 patients and prosthetic aortic valve replacement in 106 between January 1962 and December 1973. Patients who received homograft and prosthetic valves were compared with respect to age, sex, preoperative functional impairment, infection, dyspnea, angina, hemodynamics, chest X-ray, electrocardiogram, associated operations, early and late mortality, and valve failure. Combined total mortality was 28% (12% operative, 8% first postoperative year, 8% late). Ten percent of valve required replacement. One year after operation, 70% of survivors were asymptomatic, 27% were improved, and 3% were unchanged or between homograft and prosthetic valve replacement. Valve-related failure and infections were more common after homograft aortic valve replacement. Emboli, hemorrhage, and hemolysis were commoner after prosthetic valve replacement. Fungal infections occurred in five homograft patients but in no patient with a prosthetic aortic valve. Severe properative symptoms or recent endocarditis was associated with greater mortality and valve failure in both the homograft and the prosthetic series. Increased mortality and failure was also seen in patients with either preoperative aortic regurgitation with high left ventricular end-diastolic pressure and low cardiac index, or aortic stenosis with cardiomegaly or roentgenographic evidence of congestive heart failure. Therefore, in two series of patients at equal risk, mortality and valve failure were similar for homograft and prosthetic aortic valve replacement.

  8. A comparative study of nonparametric methods for pattern recognition

    NASA Technical Reports Server (NTRS)

    Hahn, S. F.; Nelson, G. D.

    1972-01-01

    The applied research discussed in this report determines and compares the correct classification percentage of the nonparametric sign test, Wilcoxon's signed rank test, and K-class classifier with the performance of the Bayes classifier. The performance is determined for data which have Gaussian, Laplacian and Rayleigh probability density functions. The correct classification percentage is shown graphically for differences in modes and/or means of the probability density functions for four, eight and sixteen samples. The K-class classifier performed very well with respect to the other classifiers used. Since the K-class classifier is a nonparametric technique, it usually performed better than the Bayes classifier which assumes the data to be Gaussian even though it may not be. The K-class classifier has the advantage over the Bayes in that it works well with non-Gaussian data without having to determine the probability density function of the data. It should be noted that the data in this experiment was always unimodal.

  9. A Comparative Study of Five Technologically Diverse CFTR Testing Platforms

    PubMed Central

    Johnson, Monique A.; Yoshitomi, Marvin J.; Richards, C. Sue

    2007-01-01

    Multiple cystic fibrosis (CF) testing platforms, using diverse and rapidly evolving technologies, are available to clinical laboratories commercially or for evaluation. Considerations when choosing a CF platform may include: sensitivity, specificity, accuracy, signal discrimination, ability to genotype, ability to reflex test, no calls/repeat rate, composition of mutation panel, hands-on time, start-to-finish time, integration into laboratory workflow, data analysis methods, flexibility regarding custom test design, and required instrumentation. Mindful of these considerations, we evaluated five technologically diverse CF platforms: 1) eSensor, an electronic detection assay system; 2) InPlex, a signal amplification methodology using a microfluidics card; 3) oligonucleotide ligation assay, an electrophoretic-based separation of amplicon-derived ligation-generated products; and two liquid bead arrays; 4) Signature, a direct hybridization assay using allele-specific capture probes; and 5) Tag-It, an assay using allele-specific primer extension and a universal microarray. A core of 150 samples, focusing on mutations in the American College of Medical Genetics/American College of Obstetricians and Gynecologists mutation panel, was tested throughout several runs for each platform. All of the platforms performed comparably in respect to sensitivity, specificity, and no-call rate. As our results indicate, consideration of all of the parameters evaluated may be useful when selecting the most appropriate platform for the specific setting. PMID:17591940

  10. Comparative study on parameter estimation methods for attenuation relationships

    NASA Astrophysics Data System (ADS)

    Sedaghati, Farhad; Pezeshk, Shahram

    2016-12-01

    In this paper, the performance and advantages and disadvantages of various regression methods to derive coefficients of an attenuation relationship have been investigated. A database containing 350 records out of 85 earthquakes with moment magnitudes of 5-7.6 and Joyner-Boore distances up to 100 km in Europe and the Middle East has been considered. The functional form proposed by Ambraseys et al (2005 Bull. Earthq. Eng. 3 1-53) is selected to compare chosen regression methods. Statistical tests reveal that although the estimated parameters are different for each method, the overall results are very similar. In essence, the weighted least squares method and one-stage maximum likelihood perform better than the other considered regression methods. Moreover, using a blind weighting matrix or a weighting matrix related to the number of records would not yield in improving the performance of the results. Further, to obtain the true standard deviation, the pure error analysis is necessary. Assuming that the correlation between different records of a specific earthquake exists, the one-stage maximum likelihood considering the true variance acquired by the pure error analysis is the most preferred method to compute the coefficients of a ground motion predication equation.

  11. Comparative studies for different proximity potentials applied to α decay

    NASA Astrophysics Data System (ADS)

    Yao, Y. J.; Zhang, G. L.; Qu, W. W.; Qian, J. Q.

    2015-09-01

    Half-lives of α decay of even-even nuclei calculated by using fourteen different versions of proximity potentials are compared to experimental data. The results show that the results of the generalized proximity potential 1977 are very much in agreement with the experimental data. In comparison with the distributions of nuclear potentials at small distances and the distributions of total potentials above the released energy Q α , it is found that at small distances the distributions of nuclear potentials have large difference and the distributions of total potentials are different among the listed proximity potentials. The different potential distributions affect the penetration probability of α, which is related to the half-life of the α decay for each nucleus. The generalized proximity potential 1977 is also used to calculate the half-lives of α decay of nuclei with odd mass numbers. The results show that the generalized proximity potential 1977 can calculate the half-lives of the α decay of almost all nuclei, which underlines and supports the use of the generalized proximity potential 1977 by Santhosh et al. in the Coulomb and proximity potential model (CPPM) and the Coulomb and proximity potential model for deformed nuclei (CPPMDN).

  12. Comparative bioequivalence study of leflunomide tablets in Indian healthy volunteers.

    PubMed

    Agarwal, S; Das, A; Ghosh, D; Sarkar, A K; Chattaraj, T K; Pal, T K

    2012-03-01

    The pharmacokinetics of teriflunomide [CAS No. 163451-81-8], the metabolite of leflunomide [CAS No. 75706-12-6] has been evaluated in adult human volunteers after oral administration of tablet formulation. However, no published data is available regarding the bioavailability of this in the Indian population. In light of the above, a study was designed to carry out a bioequivalence study of 2 preparations of leflunomide 20 mg in healthy Indian male volunteers.24 healthy male volunteers (age, 25±4.1 years; weight, 57.58±7.01 kg) were enrolled in this study. Each subject received a test and reference formulation in a single dose, fasting 2 period, 2 way crossover study with a wash out period of 4 weeks. Analysis of teriflunomide from plasma samples was done by a simple and sensitive HPLC method using UV detection developed in our laboratory. An analysis of variance was performed on the pharmacokinetic parameters Cmax, AUC0-t, AUC0-∞ using GLM procedures in which sources of variation were subject, formulation, and period.The results indicated that there are no statistically significant differences between the 2 products in either the mean concentration-time profiles or in the obtained pharmacokinetic parameters. 90% confidence limits for the log transformed data of Cmax, AUC0-t, AUC0-∞. were within the acceptable range of 0.80-1.25.The results indicate that the 2 products are bioequivalent in terms of rate and extent of drug absorption. Both the preparations were well tolerated with no adverse reactions throughout the study.

  13. Comparative study viruses with computer-aided phase microscope AIRYSCAN

    NASA Astrophysics Data System (ADS)

    Tychinsky, Vladimir P.; Koufal, Georgy E.; Perevedentseva, Elena V.; Vyshenskaia, Tatiana V.

    1996-12-01

    Traditionally viruses are studied with scanning electron microscopy (SEM) after complicated procedure of sample preparation without the possibility to study it under natural conditions. We obtained images of viruses (Vaccinia virus, Rotavirus) and rickettsias (Rickettsia provazekii, Coxiella burnetti) in native state with computer-aided phase microscope airyscan -- the interference microscope of Linnik layout with phase modulation of the reference wave with dissector image tube as coordinate-sensitive photodetector and computer processing of phase image. A light source was the He-Ne laser. The main result is coincidence of dimensions and shape of phase images with available information concerning their morphology obtained with SEM and other methods. The fine structure of surface and nuclei is observed. This method may be applied for virus recognition and express identification, investigation of virus structure and the analysis of cell-virus interaction.

  14. Asperger Syndrome and Schizophrenia: A Comparative Neuropsychological Study.

    PubMed

    Marinopoulou, Maria; Lugnegård, Tove; Hallerbäck, Maria Unenge; Gillberg, Christopher; Billstedt, Eva

    2016-07-01

    There has been an increasing interest in possible connections between autism spectrum disorder (ASD) and schizophrenia in the last decade. Neuropsychological comparison studies have, however, been few. The present study examined similarities and differences in intellectual and executive functioning between adults with Asperger syndrome (AS) and adults with schizophrenic psychosis (SP). A group with AS and a group with SP were assessed neuropsychologically with WAIS-III and D-KEFS. Similarities were found between groups, as displayed by an uneven cognitive profile, limitations in working memory, processing speed and some aspects of executive functioning. Full Scale IQ was higher in the AS group. These results add to the current research illuminating similarities and differences between ASD and schizophrenia on a cognitive level.

  15. Comparative study of normal and sensitive skin aerobic bacterial populations.

    PubMed

    Hillion, Mélanie; Mijouin, Lily; Jaouen, Thomas; Barreau, Magalie; Meunier, Pauline; Lefeuvre, Luc; Lati, Elian; Chevalier, Sylvie; Feuilloley, Marc G J

    2013-12-01

    The purpose of this study was to investigate if the sensitive skin syndrome, a frequent skin disorder characterized by abnormal painful reactions to environmental factors in the absence of visible inflammatory response, could be linked to a modification in the skin bacterial population. A total of 1706 bacterial isolates was collected at the levels of the forehead, cheekbone, inner elbow, and lower area of the scapula on the skin of normal and sensitive skin syndrome-suffering volunteers of both sexes and of different ages. Among these isolates, 21 strains were randomly selected to validate in a first step the Matrix-Assisted Laser Desorption/Ionization (MALDI)-Biotyper process as an efficient identification tool at the group and genus levels, by comparison to API(®) strips and 16S ribosomal RNA gene sequencing identification techniques. In a second step, identification of the skin microbiota isolates by the MALDI-Biotyper tool allowed to pinpoint some differences in terms of bacterial diversity with regard to the collection area, and the volunteer's age and gender. Finally, comparison of the skin microbiota from normal and sensitive skin syndrome-suffering volunteers pointed out gender-related variations but no detectable correlation between a phylum, a genus or a dominant bacterial species and the sensitive skin phenotype. This study reveals that there is no dysbiosis of aerobic cultivable bacteria associated with the sensitive skin syndrome and further demonstrates that the MALDI-Biotyper is a powerful technique that can be efficiently employed to the study of cultivable human skin bacteria. To our knowledge, this is the first study focusing on bacteria in the sensitive skin syndrome. These results are of potential importance for pharmaceutical and cosmetic industries, which are looking for new strategies to treat this multiparametric disorder.

  16. Comparative Studies of Organizational Factors, in Military Maintenance

    DTIC Science & Technology

    1979-06-01

    approach and involved utilizing a small segment of the work force to perform taskings on a team rotational basis. Successful results were obtained in...difficult and tenuous. The basic model is illustrated in Figure 1-1. The model is divided into three main parts; organizaticnal inputs, work unit, and... divided into the following specific subobjectives: First Year of Study: (1) Survey and categorize the critical organizational and interpersonal

  17. Comparative study regarding friction coefficient for three epoxy resins

    NASA Astrophysics Data System (ADS)

    Mihu, G.; Mihalache, I.; Graur, I.; Ungureanu, C.; Bria, V.

    2017-02-01

    Three commercial epoxy diglycidylether of bisphenol-A (DGEBA) were used in this study namely Epiphen RE4020-DE 4020 (Bostik), Epoxy Resin C (R&G Gmbh Waldenbuch), and Epoxy Resin HT-2 (R&G Gmbh Waldenbuch). Epoxy resins are often used for the friction purpose but their friction resistance is quite low and it is thus necessary to enhance their friction resistance. In this paper it is shown how load, sliding velocity, and distance affect friction coefficient of epoxy resins.

  18. Comparative Study of Aerodynamic Interference During AFT Dispense of Munitions

    DTIC Science & Technology

    2007-09-01

    includes both a computational and an experimental portion to complete the study. The commercial tools Gridgen , SolidMesh, SolidWorks and Fluent...redesigned strut shown in Figure 3.5 was initially generated in Gridgen , a commercial Original Cone Model: 10° half-angle cone 0.5 mm spherical tip Dia...not be overloaded. The software package Gridgen was used to develop the database structures and create custom grids. The original strut, cone and

  19. Comparative study of normal and sensitive skin aerobic bacterial populations

    PubMed Central

    Hillion, Mélanie; Mijouin, Lily; Jaouen, Thomas; Barreau, Magalie; Meunier, Pauline; Lefeuvre, Luc; Lati, Elian; Chevalier, Sylvie; Feuilloley, Marc G J

    2013-01-01

    The purpose of this study was to investigate if the sensitive skin syndrome, a frequent skin disorder characterized by abnormal painful reactions to environmental factors in the absence of visible inflammatory response, could be linked to a modification in the skin bacterial population. A total of 1706 bacterial isolates was collected at the levels of the forehead, cheekbone, inner elbow, and lower area of the scapula on the skin of normal and sensitive skin syndrome-suffering volunteers of both sexes and of different ages. Among these isolates, 21 strains were randomly selected to validate in a first step the Matrix-Assisted Laser Desorption/Ionization (MALDI)-Biotyper process as an efficient identification tool at the group and genus levels, by comparison to API® strips and 16S ribosomal RNA gene sequencing identification techniques. In a second step, identification of the skin microbiota isolates by the MALDI-Biotyper tool allowed to pinpoint some differences in terms of bacterial diversity with regard to the collection area, and the volunteer's age and gender. Finally, comparison of the skin microbiota from normal and sensitive skin syndrome-suffering volunteers pointed out gender-related variations but no detectable correlation between a phylum, a genus or a dominant bacterial species and the sensitive skin phenotype. This study reveals that there is no dysbiosis of aerobic cultivable bacteria associated with the sensitive skin syndrome and further demonstrates that the MALDI-Biotyper is a powerful technique that can be efficiently employed to the study of cultivable human skin bacteria. To our knowledge, this is the first study focusing on bacteria in the sensitive skin syndrome. These results are of potential importance for pharmaceutical and cosmetic industries, which are looking for new strategies to treat this multiparametric disorder. PMID:24151137

  20. Bristle end-rounding in children's toothbrushes: a comparative study.

    PubMed

    Rawls, H R; van Gelder, R; Smith, N K; Jeppesen, M; Yuan, C

    1993-01-01

    Animal and clinical studies have shown that sharp, unpolished toothbrush bristles can injure gingival tissues and that substantial variation exists in the degree of end-roundness of commercially available toothbrushes. In this study, eight brands of children's toothbrushes were assessed for their relative potential to cause oral tissue injury based upon the degree of end-roundness of their bristles. The brands studied were: Blend-a-dent Jr., Butler GUM Jr., Colgate Plus Jr., Johnson & Johnson Prevent Jr., Johnson & Johnson Reach Child, Lever Bros. Disney, Oral-B P20, and Sensodyne Jr. Brushes were ranked on the basis of three criteria: the percentage of bristles with sharp ends (89% roundness or less), the percentage of bristles with smooth edges (96% roundness or greater), and the average roundness of bristle ends. The Oral-B P20 brush had significantly more (p < 0.05) bristles with a roundness of 96% or greater; it also was in the group having the lowest number of bristles with sharp edges and had the highest average roundness. Based on these criteria, the Oral-B P20 showed the least potential for oral tissue damage, whereas the Johnson & Johnson Reach Child and Butler GUM Jr. showed the most potential for tissue injury. The other brands investigated were intermediate in end-rounding values and damage potential.

  1. Comparative Studies of Delignification Caused by Ganoderma Species †

    PubMed Central

    Adaskaveg, J. E.; Gilbertson, R. L.; Blanchette, R. A.

    1990-01-01

    Isolates of six species of Ganoderma in the G. lucidum complex were evaluated for their ability to decay wood of Quercus hypoleucoides A. Camus and Abies concolor (Gord. and Glend.) Lindl. ex. Hildebr. by using in vitro agar block decay tests. Morphological, ultrastructural, and chemical studies of decayed wood were used to determine the extent of delignification or simultaneous decay caused by each species of Ganoderma. All species decayed both white fir and oak wood; however, less percent weight loss (%WL) occurred in white fir than oak. In white fir, isolates of two undescribed Ganoderma species (RLG16161, RLG16162, JEA615, and JEA625) caused significantly higher%WL (21 to 26%) than that in G. colossum, G. oregonense, G. meredithiae, and G. zonatum (10 to 16%). Only Ganoderma sp. isolates JEA615 and JEA625 caused delignification, with JEA615 causing a lignin-to-glucose gram loss ratio of 1.6:1. Morphological and ultrastructural studies confirmed delignification by this fungus and showed that some delignification had occurred by all of the species, although areas of delignification were limited to small regions adjacent to simultaneously decayed cells. In oak, G. colossum caused significantly less%WL (22 to 35%) than the other species (38 to 52%). All of the species, except G. meredithiae, caused delignification with lignin-to-glucose gram loss ratios ranging from 1.4 to 4.9:1. Extensive delignification by isolates of G. colossum and G. oregonense was observed; moderate delignification was caused by the other species. Ganoderma meredithiae caused a simultaneous decay, with only small localized regions of cells delignified, while delignification by G. zonatum was irregular, with specific zones within the cell wall delignified. The thermophilic and chlamydosporic G. colossum has the capacity to cause extensive delignification and appears ideally suited for use in lignin degradation studies and biotechnological applications of lignin-degrading fungi. Images PMID

  2. Comparative studies of delignification caused by ganoderma species.

    PubMed

    Adaskaveg, J E; Gilbertson, R L; Blanchette, R A

    1990-06-01

    Isolates of six species of Ganoderma in the G. lucidum complex were evaluated for their ability to decay wood of Quercus hypoleucoides A. Camus and Abies concolor (Gord. and Glend.) Lindl. ex. Hildebr. by using in vitro agar block decay tests. Morphological, ultrastructural, and chemical studies of decayed wood were used to determine the extent of delignification or simultaneous decay caused by each species of Ganoderma. All species decayed both white fir and oak wood; however, less percent weight loss (%WL) occurred in white fir than oak. In white fir, isolates of two undescribed Ganoderma species (RLG16161, RLG16162, JEA615, and JEA625) caused significantly higher%WL (21 to 26%) than that in G. colossum, G. oregonense, G. meredithiae, and G. zonatum (10 to 16%). Only Ganoderma sp. isolates JEA615 and JEA625 caused delignification, with JEA615 causing a lignin-to-glucose gram loss ratio of 1.6:1. Morphological and ultrastructural studies confirmed delignification by this fungus and showed that some delignification had occurred by all of the species, although areas of delignification were limited to small regions adjacent to simultaneously decayed cells. In oak, G. colossum caused significantly less%WL (22 to 35%) than the other species (38 to 52%). All of the species, except G. meredithiae, caused delignification with lignin-to-glucose gram loss ratios ranging from 1.4 to 4.9:1. Extensive delignification by isolates of G. colossum and G. oregonense was observed; moderate delignification was caused by the other species. Ganoderma meredithiae caused a simultaneous decay, with only small localized regions of cells delignified, while delignification by G. zonatum was irregular, with specific zones within the cell wall delignified. The thermophilic and chlamydosporic G. colossum has the capacity to cause extensive delignification and appears ideally suited for use in lignin degradation studies and biotechnological applications of lignin-degrading fungi.

  3. Role transformation of special care unit nurses: a comparative study.

    PubMed

    Lewandowski, L A; Kramer, M

    1980-01-01

    To investigate whether special care unit nurses have characteristics different from nurses who work in nonintensive care settings and whether SCU nurses make more effective role transformations than non-SCU nurses, this posthoc descriptive study utilized data from 213 new graduate nurses in their first jobs in eight medical centers across the United States. The 213 nurses were a subsample of 307 new graduate nurses in a parent study that tested effect of a bicultural orientation program in role transformation. The nurses in the subsample worked in one of four nursing areas: medical--surgical, medical--surgical specialty, parent--child, and SCU. They were pretested at six weeks of employment regarding their: professional, bureaucratic, and service role conceptions; total role deprivation; professional, bureaucratic, and bicultural role behavior; self-esteem; and degree of self-actualization. SCU nurses had significantly higher self-actualization scores initially than medical--surgical nurses. Posttesting at nine months of employment included all of the above variables plus measures of empathy and change-agent activity. Performance ratings and resignations were examined at one year of employment. Analyses of variance of the difference scores and posttest-only scores showed no significant differences by type of unit except for self-actualization. To examine the relationship between the degree of specialization and the variables under study, units were rank ordered according to degree of specialization. Nurses working on units which required the most specialization had significantly higher increases in bicultural scores and self-esteem and trends toward higher increases in bureaucratic role conception and higher performance ratings. However, SCU nurses also had the most decrease in professional role conception scores, least increase in self-actualization scores, least amount of empathy with co-workers, and least amount of effective change-agent activity

  4. Comparative infrared study of silicon and germanium nitrides

    NASA Astrophysics Data System (ADS)

    Baraton, M. I.; Marchand, R.; Quintard, P.

    1986-03-01

    Silicon and germanium nitride (Si 3N 4 and Ge 3N 4) are isomorphic compounds. They have been studied in the β-phase which crystallises in the hexagonal system. The space group is P6 3/m (C 6h2). The IR transmission spectra of these two nitrides are very similar but the absorption frequencies of germanium nitride are shifted to the lower values in comparison with silicon nitride. We noted that the atomic mass effect is the only cause of this shift for the streching modes but not for the bending modes.

  5. A comparative study on esterases from three species of Raillietina.

    PubMed

    Balasubramanian, M P; Dhandayuthapani, S; Nellaiappan, K; Ramalingam, K

    1984-06-01

    The multiplicity of soluble esterases in Raillietina tetragona, R. echinobothrida and R. cesticillus was studied by use of slab polyacrylamide gel electrophoresis. Five fractions of esterase activity were observed in R. tetragona, seven in R. echinobothrida and three in R. cesticillus. The various fractions of esterase activity of closely related species of Raillietina showed differential behaviour towards various chemicals. Based on the inhibitory effect of inhibitors p-CMB, EDTA, malathion, silver nitrate and eserine sulphate, the various esterases have been classified into arylesterase, carboxylesterase, acetylesterase and cholinesterase.

  6. Unveiling square and triangular optical lattices: a comparative study.

    PubMed

    Silva, Juarez G; Jesus-Silva, Alcenísio J; Alencar, Márcio A R C; Hickmann, Jandir M; Fonseca, Eduardo J S

    2014-02-15

    We study square and triangular optical lattice formation using a diffraction technique with light-possessing orbital angular momentum (OAM). We demonstrate that it is possible to use Fraunhofer diffraction of light by a square aperture to unveil OAM about two times bigger than would be possible with a triangular aperture. We notice that the pattern remains truncated until a topological charge (TC) equal to 20 with good precision. Even though a square pattern cannot be used to determine the TC sign, it is possible to measure high order of the modulus and sign of the TC up to 20, combining patterns of the triangular and square apertures.

  7. HRTEM study comparing naturally and experimentally weathered pyroxenoids

    SciTech Connect

    Banfield, J.F.; Ferruzzi, G.G.; Casey, W.H.; Westrich, H.R.

    1995-01-01

    The mineralogy and chemistry of both naturally and experimentally weathered MnSiO{sub 3} chain silicate minerals (rhodonite and pyroxmangite) were compared. In natural MnSiO{sub 3}, high-resolution transmission-electron microscope observations reveal that alteration begins at grain boundaries and planar defects parallel to the silicate chains that represent junctions between regions with different chain periodicities. Dissolution along these defects results in elongate etch pits that may be partly filled by smectite. Smectite (Ca{sub 0.3}Mn{sub 2}Zn{sub 0.4}Al{sub 0.1}Si{sub 4}O{sub 10}(OH){sub 2}) also develops in larger etches at grain boundaries. The Zn apparently released by weathering of coexisting sphalerite, may facilitate crystallization of manganese-smectite; rhodochrosite is also an initial product. X-ray diffraction patterns from highly altered materials reveal only rhodochrosite and quartz. Simplified reactions are H{sub 2}CO{sub 3}(aq) + 4 MnSiO{sub 3}(s) = Mn{sub 3}Si{sub 4}O{sub 10}(OH){sub 2}(s) + MnCO{sub 3}(s) accompanied by 3H{sub 2}CO{sub 3}(aq) + Mn{sub 3}Si{sub 4}O{sub 10}(OH){sub 2}(s) = 3 MnCO{sub 3}(s) + 4SiO{sub 2}(s) + 4H{sub 2}O. Pyroxenoid dissolution is incongruent under experimental conditions. A 3-7 nm-thick layer of amorphous silica is present at the mineral surface after {approximately}2000 h of reaction in acidic and near-neutral pH solutions that were undersaturated with respect to bulk amorphous silica. This thin layer of polymeric silica, which is absent on unreacted grains, is interpreted to have formed largely by incongruent dissolution at the mineral surface as protons in solution rapidly exchange for near-surface Mn. The layer may also contain silica readsorbed back onto the surface from solution. The net result is that silica from the pyroxenoid is redistributed directly into reaction products. Upon aging in air for a year, leached layers partially recrystallize.

  8. A comparative study of dipolarization fronts at MMS and Cluster

    NASA Astrophysics Data System (ADS)

    Schmid, D.; Nakamura, R.; Volwerk, M.; Plaschke, F.; Narita, Y.; Baumjohann, W.; Magnes, W.; Fischer, D.; Eichelberger, H. U.; Torbert, R. B.; Russell, C. T.; Strangeway, R. J.; Leinweber, H. K.; Le, G.; Bromund, K. R.; Anderson, B. J.; Slavin, J. A.; Kepko, E. L.

    2016-06-01

    We present a statistical study of dipolarization fronts (DFs), using magnetic field data from MMS and Cluster, at radial distances below 12 RE and 20 RE, respectively. Assuming that the DFs have a semicircular cross section and are propelled by the magnetic tension force, we used multispacecraft observations to determine the DF velocities. About three quarters of the DFs propagate earthward and about one quarter tailward. Generally, MMS is in a more dipolar magnetic field region and observes larger-amplitude DFs than Cluster. The major findings obtained in this study are as follows: (1) At MMS ˜57 % of the DFs move faster than 150 km/s, while at Cluster only ˜35 %, indicating a variable flux transport rate inside the flow-braking region. (2) Larger DF velocities correspond to higher Bz values directly ahead of the DFs. We interpret this as a snow plow-like phenomenon, resulting from a higher magnetic flux pileup ahead of DFs with higher velocities.

  9. Why do young women use sunbeds? A comparative psychological study.

    PubMed

    Fiala, B; Kopp, M; Günther, V

    1997-12-01

    Many people are keen on getting a skin tan despite being aware of warnings of health hazards. The present study investigates differences between women regularly using sunbeds and a control group of non-users in the areas of self-concept, narcissistic regulatory modalities, social assertiveness and generalized self-efficacy. Thirty women users of suntan salons and 34 women who never used one were investigated with standardized psychological questionnaires. In addition, their knowledge about the hazards of using sunbeds and attitudes to tanning were recorded. Statistical evaluation shows that sunbed users demonstrate more object devaluation: that is, other persons are devalued so that they are not even considered worthy of affection. Furthermore, they also display greater anxiety in their feelings and relationships with others. The results of this pilot study support the hypothesis that a tanned skin, by helping sunbed users to achieve their ideal of beauty, enables them to devalue other people and thus possibly to protect themselves from close relationships. As medical information about the hazards of ultraviolet irradiation fails to make an adequate impression on them, public relations campaigns must be undertaken in order to make them aware of the underlying motives of their behaviour.

  10. A comparative study of different ferrofluid constitutive equations.

    NASA Astrophysics Data System (ADS)

    Kaloni, Purna

    2011-11-01

    Ferrofluids are stable colloidal suspensions of fine ferromagnetic monodomain nanoparticles in a non-conducting carrier fluid. The particles are coated with a surfacant to avoid agglomeration and coagulation.Brownian motion keeps the nanoparticles from settling under gravity. In recent years these fluids have found several applications including in liquid seals in rotary shafts for vacuum system and in hard disk drives of personal computers, in cooling and damping of loud speakers, in shock absorbers and in biomedical applications. A continuum description of ferrofluids was initiated by Neuringer and Rosensweig but the theory had some limitations. In subsequent years,several authors have proposed generalization of the above theory.Some of these are based upon the internal particle rotation concept, some are phemonological, some are based upon a thermodynamic framework, some employ statistical approach and some have used the dynamic mean field approach. The results based upon these theories ane in early stages and inconclusive. Our purpose is, first, to critically examine the basic foundations of these equations and then study the pedictions obtained in all the theories related to an experimental as well as a theoretical study.

  11. Comparative study of the vapor analytes of trinitrotoluene (TNT)

    NASA Astrophysics Data System (ADS)

    Edge, Cindy C.; Gibb, Julie; Dugan, Regina E.

    1998-12-01

    Trinitrotoluene (TNT) is a high explosive used in most antipersonnel and antitank landmines. The Institute for Biological Detection Systems (IBDS) has developed a quantitative vapor delivery system, termed olfactometer, for conducting canine olfactory research. The research is conducted utilizing dynamic conditions, therefore, it is imperative to evaluate the headspace of TNT to ensure consistency with the dynamic generation of vapor. This study quantified the vapor headspace of military- grade TNT utilizing two different vapor generated methodologies, static and dynamic, reflecting differences between field and laboratory environments. Static vapor collection, which closely mimics conditions found during field detection, is defined as vapor collected in an open-air environment at ambient temperature. Dynamic vapor collection incorporates trapping of gases from a high flow vapor generation cell used during olfactometer operation. Analysis of samples collected by the two methodologies was performed by gas chromatography/mass spectrometry and the results provided information with regard to the constituents detected. However, constituent concentration did vary between the sampling methods. This study provides essential information regarding the vapor constituents associated with the TNT sampled using different sampling methods. These differences may be important in determining the detection signature dogs use to recognize TNT.

  12. Comparative study of component erosion for electromagnetic and electrothermal launchers

    NASA Astrophysics Data System (ADS)

    Bourham, M. A.; Hankins, O. E.; Gilligan, J. G.; Hurley, J. D.; Earnhart, J. R.

    1993-01-01

    The electrothermal launcher SIRENS has been used to study the erosion of critical components (rails and insulators) of plasma-driven launchers. SIRENS can produce high-density (above 10 exp 25/cu m) low-temperature (1-3 eV) plasma, formed by the ablation of the insulator (Lexan), with currents up to 100 kA. The incident heat flux varies between 2 to 90 GW/sq m over 100 microsec duration, for input energies 1-10 kJ. Erosion studies have been performed on several insulators, pure and coated metals, alloys and several graphite grades. The fraction of the total incident energy that is transmitted to the eroded surface varies from 12 to 30 percent for the materials tested and decreases to 5-7 percent as the incident energy fluence increases. Such reduction in erosion for a given incident fluence is due to the vapor shield effect. The scaling law for the energy transmission factor through the vapor shield layer was obtained for the exposed materials.

  13. Comparative study of Microsporum canis isolates by DNA fingerprinting.

    PubMed

    Shafiee, Shabnam; Khosravi, Ali Reza; Ashrafi Tamai, Iradj

    2014-08-01

    Microsporum canis is a zoophilic fungus and it is an important agent of dermatophytosis. Cats act as important reservoirs. Clinically, it is too difficult to differentiate dermatophytosis caused by various species, also this fungus loses its morphological characteristics easily because of subculture; so using of rapid and accurate laboratory techniques for identifying the dermatophytes is important, therefore, RAPD-PCR was applied for the differentiation of the isolates. In this study, 10 M. canis isolates were detected in cats, dog, human, fox and rabbit at the Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran. For running the RAPD-PCR, PCR set system and three random primers OPU 15, OPU 13 and OPA 04 were used. Then phylogenetic tree and similarity coefficient table were drawn. The results showed that there were some common bands between M. canis isolates. There were some specific bands for each isolates, as well. Our study showed, despite the typical morphology of the whole isolates, they were placed in different branches in molecular typing.

  14. Comparative study of the three different fluorophore antibody conjugation strategies.

    PubMed

    Shrestha, Dilip; Bagosi, Adrienn; Szöllősi, János; Jenei, Attila

    2012-09-01

    The progression in bioconjugational chemistry has significantly contributed to the evolution and success of protein biology. Mainly, antibody chemistry has been a subject of intensive study owing to the expansion of research areas warranted by using various derivatives of conjugated antibodies. Three reactive moieties (amine, sulfhydryl and carbohydrate) in the antibodies are chiefly favored for the conjugational purpose. This feature is known for decades, nevertheless, amine based conjugation is still the most preferred strategy despite the appreciation the other two methods receive in conserving the antigen binding affinity (ABA). No single report has been published, according to our knowledge, where these three conjugation strategies were applied to the same fluorophore antibody systems. In this study, we evaluated conjugation yield, time demand and cost efficiency of these conjugation procedures. Our results showed that amine based conjugations was by far the best technique due to its simplicity, rapidity, ease of operation, higher conjugate yield, cheaper cost and potential for larger fluorophore/protein labeling ratio without having much effect in ABA. Furthermore, sulfhydryl labeling clearly excelled in terms of reduced non-specific binding and mild effect in ABA but was usually complicated by an asymmetric antibody reduction due to mercaptoethylamine while carbohydrate oxidation based strategy performed the worst during our experiment.

  15. Classification of adaptive memetic algorithms: a comparative study.

    PubMed

    Ong, Yew-Soon; Lim, Meng-Hiot; Zhu, Ning; Wong, Kok-Wai

    2006-02-01

    Adaptation of parameters and operators represents one of the recent most important and promising areas of research in evolutionary computations; it is a form of designing self-configuring algorithms that acclimatize to suit the problem in hand. Here, our interests are on a recent breed of hybrid evolutionary algorithms typically known as adaptive memetic algorithms (MAs). One unique feature of adaptive MAs is the choice of local search methods or memes and recent studies have shown that this choice significantly affects the performances of problem searches. In this paper, we present a classification of memes adaptation in adaptive MAs on the basis of the mechanism used and the level of historical knowledge on the memes employed. Then the asymptotic convergence properties of the adaptive MAs considered are analyzed according to the classification. Subsequently, empirical studies on representatives of adaptive MAs for different type-level meme adaptations using continuous benchmark problems indicate that global-level adaptive MAs exhibit better search performances. Finally we conclude with some promising research directions in the area.

  16. Comparative studies of perceived vibration strength for commercial mobile phones.

    PubMed

    Lee, Heow Pueh; Lim, Siak Piang

    2014-05-01

    A mobile phone, also known as cell phone or hand phone, is among the most popular electrical devices used by people all over the world. The present study examines the vibration perception of mobile phones by co-relating the relevant design parameters such as excitation frequency, and size and mass of mobile phones to the vibration perception survey by volunteers. Five popular commercially available mobile phone models were tested. The main findings for the perception surveys were that higher vibration frequency and amplitude of the peak acceleration would result in stronger vibration perception of the mobile phones. A larger contact surface area with the palms and figures, higher peak acceleration and the associated larger peak inertia force may be the main factors for the relatively higher vibration perception. The future design for the vibration alert of the mobile phones is likely to follow this trend.

  17. FT-IR spectroscopy of lipoproteins—A comparative study

    NASA Astrophysics Data System (ADS)

    Krilov, Dubravka; Balarin, Maja; Kosović, Marin; Gamulin, Ozren; Brnjas-Kraljević, Jasminka

    2009-08-01

    FT-IR spectra, in the frequency region 4000-600 cm -1, of four major lipoprotein classes: very low density lipoprotein (VLDL), low density lipoprotein (LDL) and two subclasses of high density lipoproteins (HDL 2 and HDL 3) were analyzed to obtain their detailed spectral characterization. Information about the protein domain of particle was obtained from the analysis of amide I band. The procedure of decomposition and curve fitting of this band confirms the data already known about the secondary structure of two different apolipoproteins: apo A-I in HDL 2 and HDL 3 and apo B-100 in LDL and VLDL. For information about the lipid composition and packing of the particular lipoprotein the well expressed lipid bands in the spectra were analyzed. Characterization of spectral details in the FT-IR spectrum of natural lipoprotein is necessary to study the influence of external compounds on its structure.

  18. Comparative Study of the Labial Gland Secretion in Termites (Isoptera)

    PubMed Central

    Sillam-Dussès, David; Krasulová, Jana; Vrkoslav, Vladimír; Pytelková, Jana; Cvačka, Josef; Kutalová, Kateřina; Bourguignon, Thomas; Miura, Toru; Šobotník, Jan

    2012-01-01

    Labial glands are present in all castes and developmental stages of all termite species. In workers, their secretion contains a food-marking pheromone and digestive enzymes, while soldier secretion plays a defensive role. However, these functions were studied only in a limited set of species, and do not allow drawing general conclusions. Hence, we have investigated the chemical composition of the labial gland extracts from soldiers and workers in 15 termite species belonging to 6 families using an integrative approach based on proteomic and small-molecule profiling. We confirmed the presence of hydroquinone and cellulase in the labial glands of workers, and we identified new toxic compounds in soldiers and workers of several species. Our results highlight the dual role of labial gland secretion, i.e. the defensive role in soldiers and workers of several termite species, and the digestive function in workers. PMID:23071569

  19. A comparative study of linear and nonlinear MIMO feedback configurations

    NASA Technical Reports Server (NTRS)

    Desoer, C. A.; Lin, C. A.

    1984-01-01

    In this paper, a comparison is conducted of several feedback configurations which have appeared in the literature (e.g. unity-feedback, model-reference, etc.). The linear time-invariant multi-input multi-output case is considered. For each configuration, the stability conditions are specified, the relation between achievable I/O maps and the achievable disturbance-to-output maps is examined, and the effect of various subsystem perturbations on the system performance is studied. In terms of these considerations, it is demonstrated that one of the configurations considered is better than all the others. The results are then extended to the nonlinear multi-input multi-output case.

  20. Metals in wheat flour; comparative study and safety control.

    PubMed

    Tejera, Raquel L; Luis, G; González-Weller, Dailos; Caballero, José M; Gutiérrez, Angel J; Rubio, Carmen; Hardisson, Arturo

    2013-01-01

    Cereal industry and its derived products have a big economic and social importance worldwide. Therefore, as wheat flour is a commodity for all bread and bakery industry, it is safety is of high nutrition and toxicological interest. In this investigation we intend to study and determine the content of twelve metals in 50 samples of wheat flour coming from a wheat flour industry. Macro elements sodium, potassium magnesium and calcium, micro elements manganese, iron, copper, zinc, chrome and nickel as well as toxic trace elements cadmium and lead have been analysed. The estimated diary intake of each metal and their contribution in percentage terms to the RDI (macro and micro elements) and to the PTWI (toxic elements) has been determined. Contribution of Cd and Pb to the PTWI was very low, a fact that shows safety in this wheat flour concerning toxic metals.

  1. Comparative study of the labial gland secretion in termites (Isoptera).

    PubMed

    Sillam-Dussès, David; Krasulová, Jana; Vrkoslav, Vladimír; Pytelková, Jana; Cvačka, Josef; Kutalová, Kateřina; Bourguignon, Thomas; Miura, Toru; Šobotník, Jan

    2012-01-01

    Labial glands are present in all castes and developmental stages of all termite species. In workers, their secretion contains a food-marking pheromone and digestive enzymes, while soldier secretion plays a defensive role. However, these functions were studied only in a limited set of species, and do not allow drawing general conclusions. Hence, we have investigated the chemical composition of the labial gland extracts from soldiers and workers in 15 termite species belonging to 6 families using an integrative approach based on proteomic and small-molecule profiling. We confirmed the presence of hydroquinone and cellulase in the labial glands of workers, and we identified new toxic compounds in soldiers and workers of several species. Our results highlight the dual role of labial gland secretion, i.e. the defensive role in soldiers and workers of several termite species, and the digestive function in workers.

  2. Comparative study on friction force pattern anisotropy of graphite

    NASA Astrophysics Data System (ADS)

    Liu, Zhihua; Wang, Wenxue; Liu, Lianqing

    2015-03-01

    In this paper, the experimental and theoretical studies on the atomic-scale two-dimensional friction force pattern are presented. Atomic-scale friction experiments were conducted on graphite surfaces with the atomic force microscopy (AFM) under ambient conditions. Owing to the dimensionality reduction effect of optical method detecting the probe cantilever deflection, the friction force patterns were revealed in these experiments. The friction phenomenon was analyzed theoretically in the framework of Prandtl-Tomlinson model in two dimensions. The dimensionality reduction effect was formulated and involved in the model. The comparison shows the good quantitative agreement between experimental and simulation results, suggesting that the friction force pattern can be interpreted reliably using the model. Meanwhile atomic arrangement was obtained in friction force pattern, the origin and variation of which were also analyzed. The condition for appearance of atomic arrangement was determined qualitatively. By means of band-pass filtering, hexagonal rings or crystal lattices images of graphite were obtained.

  3. Vaccination Strategies: a comparative study in an epidemic scenario

    NASA Astrophysics Data System (ADS)

    Prates, D. B.; Jardim, C. L. T. F.; Ferreira, L. A. F.; da Silva, J. M.; Kritz, M. V.

    2016-08-01

    Epidemics are an extremely important matter of study within the Mathematical Modeling area and can be widely found in the literature. Some epidemiological models use differential equations, which are very sensible to parameters, to represent and describe the diseases mathematically. For this work, a variation of the SIR model is discussed and applied to a certain epidemic scenario, wherein vaccination is introduced through two different strategies: constant vaccination and vaccination in pulses. Other epidemiological and population aspects are also considered, such as mortality/natality and infection rates. The analysis and results are performed through numerical solutions of the model and a special attention is given to the discussion generated by the paramenters variation.

  4. Comparative study of career development and training programs

    NASA Technical Reports Server (NTRS)

    Tsao, Alan

    1988-01-01

    Improvement of human capital has been identified as the key to any further increase of productivity for any country engaged in the global economic competition. The same can be said of any organization seeking to enhance its overall performance. This study is aimed at: (1) surveying the current practices of career development and training programs at major corporations and government research organizations; (2) presenting the distributions of various program features among survey respondents; (3) identifying the profile of the training program of a typical research organization, against which each organization can check and identify its relative strengths as well as areas needing further strengthening; (4) conducting an economic analysis of the effectiveness of the training programs at Langley Research Center; and (5) making recommendations as to how to enhance existing training programs.

  5. Collecting and analyzing DNA evidence from fingernails: a comparative study.

    PubMed

    Hebda, Lisa M; Doran, Ashley E; Foran, David R

    2014-09-01

    Forensic practitioners and crime laboratories regularly collect and analyze fingernail evidence; however, the best techniques for processing such evidence have not been established. In this study, numerous aspects of fingernail evidence processing-collection of exogenous cells, transportation, purification of DNA, and STR analysis-were analyzed using fingernails harboring applied blood or epithelial cells from scratchings. Autosomal STR mixtures resulted when fingernails were soaked or swabbed, while scrapings rarely generated mixtures but exhibited allelic dropout. Y-STRs yielded single source profiles, with scrapings again showing dropout. A silica-based kit extraction recovered significantly more exogenous DNA than did organic extraction, neither of which was affected by nail polish. Swabbing nails in succession resulted in some cross-contamination from exogenous material, while transporting nails together did not, although there was loss of exogenous cells. Optimized nail processing produced complete Y-STR profiles of male volunteers from female fingernails following scratchings.

  6. Comparative study of wild edible mushrooms as sources of antioxidants.

    PubMed

    Witkowska, Anna M; Zujko, Małgorzata E; Mirończuk-Chodakowska, Iwona

    2011-01-01

    The purpose of the study was to explore sixteen of the most popular edible species of wild-growing mushrooms as potential sources of antioxidants. Among the mushrooms tested, the highest total polyphenol contents, exceeding 100 mg/100 g fresh mass, were found in five mushrooms: Boletus chrysenteron, B. edulis, Leccinum scabrum, L. aurantiacum, and Macrolepiota procera. Antioxidant activity was measured with the FRAP, TEAC, DPPH scavenging ability and ferrous ions chelating ability assays. Results of the study show that wild mushrooms vary according to their antioxidant properties. The highest FRAP potentials, exceeding 1 mmol/100 g, were found in five species ofBoletales: Boletus edulis, B. chrysenteron, Leccinum scabrum, L. aurantiacum, and Suillus grevillei. TEAC values were from 1.07 to 4.01 mmol/100 g fresh mass. High TEAC values (>2.3 mmol/100 g) were found in Leccinum scabrum, L. aurantiacum, Macrolepiota procera, Boletus chrysenteron, and B. edulis. The DPPH radical scavenging effectiveness of mushroom extracts, expressed as EC50 values, was in range 2.91-13.86 mg/mL. Scavenging ability was the highest for B. edulis and B. chrysenteron. The metal chelating ability of mushroom extracts expressed as ECso values of chelating ability on ferrous ions were from 8.02 mg/mL in Cantharellus cibarius to 12.10 mg/mL in Suillus luteus. Among the mushrooms tested, Boletus chrysenteron and B. edulis were characterized by high scores of polyphenol contents and antioxidant activity in the FRAP, TEAC, and DPPH assays. These results place these culinary species of wild-growing mushrooms among products with considerable antioxidant potential.

  7. Comparative Analysis Study of Open Source GIS in Malaysia

    NASA Astrophysics Data System (ADS)

    Rasid, Muhammad Zamir Abdul; Kamis, Naddia; Khuizham Abd Halim, Mohd

    2014-06-01

    Open source origin might appear like a major prospective change which is qualified to deliver in various industries and also competing means in developing countries. The leading purpose of this research study is to basically discover the degree of adopting Open Source Software (OSS) that is connected with Geographic Information System (GIS) application within Malaysia. It was derived based on inadequate awareness with regards to the origin ideas or even on account of techie deficiencies in the open origin instruments. This particular research has been carried out based on two significant stages; the first stage involved a survey questionnaire: to evaluate the awareness and acceptance level based on the comparison feedback regarding OSS and commercial GIS. This particular survey was conducted among three groups of candidates: government servant, university students and lecturers, as well as individual. The approaches of measuring awareness in this research were based on a comprehending signal plus a notion signal for each survey questions. These kinds of signs had been designed throughout the analysis in order to supply a measurable and also a descriptive signal to produce the final result. The second stage involved an interview session with a major organization that carries out available origin internet GIS; the Federal Department of Town and Country Planning Peninsular Malaysia (JPBD). The impact of this preliminary study was to understand the particular viewpoint of different groups of people on the available origin, and also their insufficient awareness with regards to origin ideas as well as likelihood may be significant root of adopting level connected with available origin options.

  8. Comparative studies on different nanofiber photocatalysts for water splitting

    NASA Astrophysics Data System (ADS)

    Alharbi, Abdulaziz; Alarifi, Ibrahim M.; Khan, Waseem S.; Asmatulu, Ramazan

    2016-04-01

    Water splitting using photocatalyst has become a topic of recent investigation since it has the potential of producing hydrogen for clean energy from sunlight. An extensive number of solid photocatalysts have been studied for overall water splitting in recent years. In this study, two methods were employed to synthesize two different photocatalysts for water splitting. The first method describes the synthesis of nickel oxide-loaded strontium titanate (NiO-SrTiO3) particles on electrospun polyacrylonitrile (PAN) nanofibers incorporated with graphene nanoplatelets for water splitting. The electrospun PAN fibers were first oxidized at 270°C for two hours and subsequently immersed in a solution containing ethanol, titanium (IV)-isopropoxide [C12H28O4Ti] and strontium nitrate [Sr(NO3)2]. This solution was then treated with NiO nanoparticles dispersed in toluene. The surface treated PAN fibers were annealed at 600°C in air for 1 hour to transform fibers into a crystalline form for improved photocatalyst performance. In the second method, coaxial electrospinning process was used to produce core/shell strontium titanate/nickel oxide (SrTiO3-NiO) nanofibers. In coaxial method, poly (vinyl pyrrolidone) (PVP) was dissolved in deionized (DI) water, and then titanium (IV) isopropoxide [C12H28O4Ti] and strontium nitrate [Sr(NO3)2] were added into the solution to form the inner (core) layer. For outer (shell) solution, polyacrylonitrile (PAN) polymer was dissolved in dimethylformamide (DMF) at a weight ratio of 10:90 and then nickel oxide was mixed with the solution. Ultraviolet (UV) spectrophotometry and static contact angle measurement techniques were employed to characterize the structural properties of photocatalysts produced by both methods and a comparison was made between the two photocatalysts. The morphology and diameter of the nanofibers were observed by scanning electron microscopy (SEM). The structure and crystallinity of the calcined nanofibers were also observed

  9. Comparative Study of Advanced Turbulence Models for Turbomachinery

    NASA Technical Reports Server (NTRS)

    Hadid, Ali H.; Sindir, Munir M.

    1996-01-01

    A computational study has been undertaken to study the performance of advanced phenomenological turbulence models coded in a modular form to describe incompressible turbulent flow behavior in two dimensional/axisymmetric and three dimensional complex geometry. The models include a variety of two equation models (single and multi-scale k-epsilon models with different near wall treatments) and second moment algebraic and full Reynolds stress closure models. These models were systematically assessed to evaluate their performance in complex flows with rotation, curvature and separation. The models are coded as self contained modules that can be interfaced with a number of flow solvers. These modules are stand alone satellite programs that come with their own formulation, finite-volume discretization scheme, solver and boundary condition implementation. They will take as input (from any generic Navier-Stokes solver) the velocity field, grid (structured H-type grid) and computational domain specification (boundary conditions), and will deliver, depending on the model used, turbulent viscosity, or the components of the Reynolds stress tensor. There are separate 2D/axisymmetric and/or 3D decks for each module considered. The modules are tested using Rocketdyn's proprietary code REACT. The code utilizes an efficient solution procedure to solve Navier-Stokes equations in a non-orthogonal body-fitted coordinate system. The differential equations are discretized over a finite-volume grid using a non-staggered variable arrangement and an efficient solution procedure based on the SIMPLE algorithm for the velocity-pressure coupling is used. The modules developed have been interfaced and tested using finite-volume, pressure-correction CFD solvers which are widely used in the CFD community. Other solvers can also be used to test these modules since they are independently structured with their own discretization scheme and solver methodology. Many of these modules have been

  10. Genomic Comparative Study of Bovine Mastitis Escherichia coli

    PubMed Central

    Kempf, Florent; Slugocki, Cindy; Blum, Shlomo E.; Leitner, Gabriel; Germon, Pierre

    2016-01-01

    Escherichia coli, one of the main causative agents of bovine mastitis, is responsible for significant losses on dairy farms. In order to better understand the pathogenicity of E. coli mastitis, an accurate characterization of E. coli strains isolated from mastitis cases is required. By using phylogenetic analyses and whole genome comparison of 5 currently available mastitis E. coli genome sequences, we searched for genotypic traits specific for mastitis isolates. Our data confirm that there is a bias in the distribution of mastitis isolates in the different phylogenetic groups of the E. coli species, with the majority of strains belonging to phylogenetic groups A and B1. An interesting feature is that clustering of strains based on their accessory genome is very similar to that obtained using the core genome. This finding illustrates the fact that phenotypic properties of strains from different phylogroups are likely to be different. As a consequence, it is possible that different strategies could be used by mastitis isolates of different phylogroups to trigger mastitis. Our results indicate that mastitis E. coli isolates analyzed in this study carry very few of the virulence genes described in other pathogenic E. coli strains. A more detailed analysis of the presence/absence of genes involved in LPS synthesis, iron acquisition and type 6 secretion systems did not uncover specific properties of mastitis isolates. Altogether, these results indicate that mastitis E. coli isolates are rather characterized by a lack of bona fide currently described virulence genes. PMID:26809117

  11. A comparative study of 28 culture media for Trichomonas gallinae

    USGS Publications Warehouse

    Diamond, L.S.

    1954-01-01

    1. 1. A study was made of the ability of 28 different culture media to support growth of 5 strains of Trichomonas gallinae with their normally associated bacteria. A standard inoculum of 50 protozoa was used, and the cultures were incubated at 35 ?C. Based upon the number of positive cultures obtained, abundance of growth, and number of strains which grew in a given medium, the most satisfactory were Ringer-Loeffler serum, saline-Loeffler serum, and saline-serum. 2. 2. Pigeon serum used alone in a simple saline solution produced abundant growth and when added to other nutrients greatly enhanced the medium. Autoclaving of the serum appeared to have no effect on its growth promoting qualities. 3. 3. Neither egg yolk nor egg albumin alone appeared capable of supporting appreciable growth of T. gallinae. 4. 4. In general, the heavier the bacterial population supported by a medium the poorer the growth of T. gallinae. 5. 5. Strains of T. gallinae differ in their culturability. One strain grew in 82% of the media tested, another only in 43%.

  12. Cutting Efficiency of Instruments with Different Movements: a Comparative Study

    PubMed Central

    Plotino, Gianluca; Al-Sudani, Dina; Rubini, Alessio Giansiracusa; Sannino, Gianpaolo; Piasecki, Lucila; Putortì, Ermanno; Testarelli, Luca; Gambarini, Gianluca

    2015-01-01

    ABSTRACT Objectives The aim of the present study was to evaluate the cutting efficiency of two new reciprocating instruments, Twisted File Adaptive and WaveOne Primary. Material and Methods 10 new Twisted File Adaptive (TF Adaptive) (SybronEndo, Glendora, CA, USA) and 10 new WaveOne Primary files (Dentsply Maillefer, Ballaigues, Switzerland) were activated using a torque-controlled motor, respectively TFA motor (SybronEndo, Glendora, CA, USA) and Silver motor (VDW, Munich, Germany). The device used for the cutting test consisted on a mainframe to which a mobile plastic support for the hand-piece is connected and a stainless-steel block containing a Plexiglas block against which the cutting efficiency of the instruments was tested. The length of the block cut in 1 minute was measured in a computerized program with a precision of 0.1 mm. Mean and standard deviations of each group were calculated and data were statistically analyzed with one-way ANOVA and Bonferroni t test (P < 0.05). Results TF Adaptive displayed significantly greater maximum penetration depth than WaveOne Primary (P < 0.05). In fact, TF Adaptive instruments (Group 1) cut the Plexiglas block to a mean depth of 8.7 (SD 0.5) mm, while WaveOne Primary instruments cut the Plexiglas block to a mean depth of 6.4 (SD 0.3) mm. Conclusions Twisted File Adaptive instruments demonstrated statistically higher cutting efficiency than WaveOne instruments. PMID:25937877

  13. Comparative study of supertips for electron field emitters

    NASA Astrophysics Data System (ADS)

    Koops, Hans W. P.; Weber, Mark A.; Urban, J.; Schoessler, C.

    1995-09-01

    A numerical study of tips and supertips prone for fieldemission sources is performed using a 3D numerical electron optics package. Special supertips are fabricated with additive lithography under computer control. Different materials are used to generate amorphous or nanocrystalline tips. Its performance is simulated. Additive lithography using electron beam induced deposition allows to design base radii from 50 to 1000 nm. Tip radii and tip length of similar dimensions can be generated. Supertips on top of a deposited tip can have a radius as small as 5 nm. This is achieved using a high resolution scanning electron microscope with a cold field emission source. Gold-tips are constructed on top of Pt/Ir-wire tips. The positioning accuracy is 20 nm. Tips are routinely produced with aspect ratios of 5 to 10 and give an additional field enhancement factor. The influence of the nanocrystallinity of the deposited material to the field enhancement is investigated. Nanocrystals at the tip enhance the field up to a factor of 4. This effect explains the high emission current obtained in experiments from nanocrystalline tips.

  14. Epigenetic mechanisms and memory strength: a comparative study.

    PubMed

    Federman, Noel; Zalcman, Gisela; de la Fuente, Verónica; Fustiñana, Maria Sol; Romano, Arturo

    2014-01-01

    Memory consolidation requires de novo mRNA and protein synthesis. Transcriptional activation is controlled by transcription factors, their cofactors and repressors. Cofactors and repressors regulate gene expression by interacting with basal transcription machinery, remodeling chromatin structure and/or chemically modifying histones. Acetylation is the most studied epigenetic mechanism of histones modifications related to gene expression. This process is regulated by histone acetylases (HATs) and histone deacetylases (HDACs). More than 5 years ago, we began a line of research about the role of histone acetylation during memory consolidation. Here we review our work, presenting evidence about the critical role of this epigenetic mechanism during consolidation of context-signal memory in the crab Neohelice granulata, as well as during consolidation of novel object recognition memory in the mouse Mus musculus. Our evidence demonstrates that histone acetylation is a key mechanism in memory consolidation, functioning as a distinctive molecular feature of strong memories. Furthermore, we found that the strength of a memory can be characterized by its persistence or its resistance to extinction. Besides, we found that the role of this epigenetic mechanism regulating gene expression only in the formation of strongest memories is evolutionarily conserved.

  15. Comparative studies for serodiagnosis of haemorrhagic septicaemia in cattle sera

    PubMed Central

    El-Jakee, Jakeen K.; Ali, Samah Said; El-Shafii, Soumaya Ahmed; Hessain, Ashgan M.; Al-Arfaj, Abdullah A.; Mohamed, Moussa I.

    2015-01-01

    Haemorrhagic septicaemia caused by Pasteurella multocida is a major epizootic disease in cattle and buffaloes in developing countries with high morbidity and mortality rate. In the present study, a total of 88 P. multocida isolates were isolated from 256 nasopharyngeal swabs and lung tissues samples (34.4%) during the period from January, 2013 to March, 2014 from different governorates located in Egypt. Dead calves showed the highest percentage of P. multocida isolation followed by the emergency slaughtered calves, diseased calves then apparently healthy ones. These isolates were confirmed as P. multocida microscopically, biochemically by traditional tests and by API 20E commercial kit then by PCR. The percentages of positive serum samples using somatic antigen and micro-agglutination test at 1/1280 diluted serum were 10%, 54.49% and 0% in apparently healthy, diseased and emergency slaughtered samples, respectively whereas, the percentages using capsular antigen and indirect haemagglutination test were 40%, 60.89% and 60% in apparently healthy, diseased and emergency slaughtered samples, respectively. The ELISA showed the highest sensitivity for diagnosing P. multocida in apparently healthy, diseased and emergency slaughtered animals with percentages of 42%; 92.9% and 80%, respectively. The obtained results revealed that the ELISA using capsular antigen of P. multocida is a more sensitive and specific serological test for diagnosis of haemorrhagic septicaemia. PMID:26858538

  16. Cold-active enzymes studied by comparative molecular dynamics simulation.

    PubMed

    Spiwok, Vojtech; Lipovová, Petra; Skálová, Tereza; Dusková, Jarmila; Dohnálek, Jan; Hasek, Jindrich; Russell, Nicholas J; Králová, Blanka

    2007-04-01

    Enzymes from cold-adapted species are significantly more active at low temperatures, even those close to zero Celsius, but the rationale of this adaptation is complex and relatively poorly understood. It is commonly stated that there is a relationship between the flexibility of an enzyme and its catalytic activity at low temperature. This paper gives the results of a study using molecular dynamics simulations performed for five pairs of enzymes, each pair comprising a cold-active enzyme plus its mesophilic or thermophilic counterpart. The enzyme pairs included alpha-amylase, citrate synthase, malate dehydrogenase, alkaline protease and xylanase. Numerous sites with elevated flexibility were observed in all enzymes; however, differences in flexibilities were not striking. Nevertheless, amino acid residues common in both enzymes of a pair (not present in insertions of a structure alignment) are generally more flexible in the cold-active enzymes. The further application of principle component analysis to the protein dynamics revealed that there are differences in the rate and/or extent of opening and closing of the active sites. The results indicate that protein dynamics play an important role in catalytic processes where structural rearrangements, such as those required for active site access by substrate, are involved. They also support the notion that cold adaptation may have evolved by selective changes in regions of enzyme structure rather than in global change to the whole protein.

  17. Social Impact of Solar Eclipse in Indonesia: A Comparative Study

    NASA Astrophysics Data System (ADS)

    Mumpuni, Emanuel S.; Hidayat, Bambang

    2012-09-01

    The social impact and public comprehension of the natural phenomenon varies depending on how a particular cultural background perceives the phenomenon and how the interaction between general public and the authoritative bodies has persisted. While astronomers and scientists have taken for granted that solar eclipse is a natural phenomenon and subjected it to various scientific studies, large percentages of the population have been left uninformed scientifically and have responded to the phenomena quite differently. The technical and scientific aspects of the earliest expedition, to Padang (Sumatra) in 1901, have recently been discussed at length.Two major solar eclipses, namely the 1926 and 1929, offered many scientific outputs as well as results on observations of societies: anthropology, demography, and culinary habits of the local inhabitants. Those days, science was the preserve of a few selected. To a certain degree, many old perceptions of on natural phenomena, with their ruling deities still lingered on. The purpose of this paper is to show the changing views of the endogenous population in particular after the government's massive efforts to enlighten the people and to empower the younger generations in comprehending natural phenomena. The great efforts of the Government of Indonesia's Institute of Sciences (LIPI) related to the June 1983 solar eclipse produced a dramatic change in the sense of appreciation of solar eclipse as a natural phenomenon in consequence of relative motions of the Sun, Moon and the Earth. It took however another five years, till the time of the great eclipse in 1988, to a full fruition in which younger generations as well as older ones abandoned almost completely the old views and embarked on the understanding the value of solar eclipse for science.

  18. Absorbable scaphoid screw development: a comparative study on biomechanics

    PubMed Central

    Wang, Yi; Song, Muguo; Xu, Yongqing; He, Xiaoqing; Zhu, YueLiang

    2016-01-01

    Background The scaphoid is critical for maintaining the stability and movement of the wrist joints. This study aimed to develop a new internal fixator absorbable scaphoid screw (ASS) for fixation of the scaphoid waist after fracture and to test the biomechanical characteristics of ASS. Materials and methods An ASS was prepared using polylactic acids and designed based on scaphoid measurements and anatomic features. Twenty fractured scaphoid waist specimens were randomly divided into experimental and control groups (n=10/group). Reduction and internal fixation of the scaphoid were achieved with either Kirschner wires (K-wires) or ASS. A moving target simulator was used to test palmar flexion and dorsal extension, with the range of testing (waist movement) set from 5° of palmar flexion to 25° of dorsal extension. Flexion and extension were repeated 2,000 times for each specimen. Fracture gap displacements were measured with a computerized tomography scanning. Scaphoid tensile and bending strengths were measured by using a hydraulic pressure biomechanical system. Results Prior to biomechanical fatigue testing, fracture gap displacements were 0.16±0.02 mm and 0.22±0.02 mm in the ASS and K-wire groups, respectively. After fatigue testing, fracture gap displacements in the ASS and the K-wire groups were 0.21±0.03 mm and 1.52±0.07 mm, respectively. The tensile strengths for the ASS and K-wire groups were 0.95±0.02 MPa and 0.63±0.02 MPa, respectively. Conclusion Fixation using an ASS provided sufficient mechanical support for the scaphoid after fracture. PMID:27217756

  19. A comparative study of atmospheric corrosion in the Caribbean area

    SciTech Connect

    Maldonado, L.; Castro, P.; Echeverria, M.

    1995-10-01

    Atmospheric corrosion is a phenomenon of such a magnitude that has been cause of study in several countries for decades. Nevertheless, in Mexico, it became of recent interest due to new economic factors that have involved the Peninsula of Yucatan too. The Yucatan Peninsula is limited to the North and West by the Gulf of Mexico and to the East by the Caribbean Sea. This is a non industrialized region so that in the past very little importance was given to the atmospheric corrosion damage or to the quantification of the high corrosion rates, empirically observed. However, in recent times increased tourism, industrial growth and petroleum extraction have exhibited the need for a better understanding of the atmospheric corrosion processes, as well as a realistic correlation to parameters such as time-of-wetness, levels of pollution by airborne salinity, atmospheric S0{sub 2} and corrosivity categories for the metals. To evaluate these parameters, five tests sites were selected following ISO recommendations. Three sites are marines atmospheres, one urban and one rural. Corrosion rates for commercial laminated Cu and carbon steel, as well as deposition rates of pollutants, were determined after one year exposure in the test sites. Applying the standard practice ISO 9223 a categorization of the corrosivity and of the level of pollutants was carried out. The marine environments were classified as of atmospheric corrosivity C{sub 5}, while the urban and the rural could be classified as C{sub 3}, respectively. The pollution values showed that the exposure sites were essentially contaminated with chloride with classification S{sub 1} for the rural site and S{sub 3} for the marine atmosphere.

  20. [Comparative studies of patient positioning for lumbar intervertebral disk operation].

    PubMed

    Rudolph, Ch; Schaffranietz, L; Hellmundt, L; Vitzthum, H E; Olthoff, D

    2002-01-01

    For surgery on lumbar disks by the posterior route, patients are placed either on a Wilson frame or in genupectoral position. The aim of the prospective study was to record and describe the haemodynamic changes resulting from the patients' position. After written informed consent had been received, 80 neurosurgical patients undergoing lumbar disk surgery were randomly divided into two groups; group I--Wilson frame, group II--genupectoral position. In each group, 20 patients received total intravenous anaesthesia (Alfentanil or Remifentanil, Propofol) and 20 balanced anaesthesia with Isoflurane and Alfentanil or Remifentanil. Haemodynamic parameters (mean arterial pressure--MAP and heart rate--HR) were recorded automatically at three measuring times (MT): firstly, after induction of anaesthesia; secondly, before re-direction; thirdly, after re-direction on the Wilson frame or in the genupectoral position. Induction of anaesthesia did not lead to a significant decrease in MAP (MT 1: 92.5 +/- 15.2 mmHg, MT 2: 89 +/- 13.4 mmHg, n = 80). In group I (n = 40), no significant changes were observed in MAP and HR at MT 3 (p = 0.882, p = 0.051). In comparison to group I, the genupectoral position was associated with significant drops in MAP and HR. The genupectoral position caused a significant decrease in MAP (p < 0.001) and HR (p = 0.016) at MT 3. Our data suggest that body weight or body mass index do not necessarily lead to a preference for one of the two possible positions of the patient. Complications resulting from haemodynamic changes were not seen in either group. We recommend the Wilson frame for neurosurgical lumbar disk surgery in cases of cardiovascular or cerebrovascular disorders. The adaptive capacities in the genupectoral position as a result of the modifying distribution of blood volume are limited in these patients. Furthermore, the dose-dependent effects of different anaesthetics on haemodynamic parameters in these prone positions should be explored.