Cobalt-Chromium (Co-Cr) alloys are classified as predominantly base-metal alloys and are widely known for their biomedical applications in the orthopedic and dental fields. In dentistry, Co-Cr alloys ...are commonly used for the fabrication of metallic frameworks of removable partial dentures and recently have been used as metallic substructures for the fabrication of porcelain-fused-to-metal restorations and implant frameworks. The increased worldwide interest in utilizing Co-Cr alloys for dental applications is related to their low cost and adequate physico-mechanical properties. Additionally, among base-metal alloys, Co-Cr alloys are used more frequently in many countries to replace Nickel-Chromium (Ni-Cr) alloys. This is mainly due to the increased concern regarding the toxic effects of Ni on the human body when alloys containing Ni are exposed to the oral cavity. This review article describes dental applications, metallurgical characterization, and physico-mechanical properties of Co-Cr alloys and also addresses their clinical and laboratory behavior in relation to those properties.
CD117 (C-kit) is thought to play an important role in tumourigenesis. There are limited data in the literature concerning C-kit expression in retinoblastoma. To date, no immunohistochemical studies ...have been performed to assess the possible association of C-kit with vascular endothelial growth factor (VEGF) in retinoblastoma. This study was designed to investigate C-kit and VEGF immunoexpression in retinoblastoma, their relationship with prognostic parameters as well as the correlation between them. A prospective immunohistochemical study was conducted on 56 retinoblastoma cases. Patients who had received preoperative chemotherapy were excluded. Positive C-kit and VEGF immunoreactivity was observed in 48.2% and 76.8% of retinoblastoma cases respectively. No C-kit immunostaining was seen in the adjacent uninvolved retina. However, VEGF expression was detected within its vasculature. Retinoblastomas with combined pattern of tumour growth revealed a highly significant positive C-kit expression (P = 0.002) compared to cases with endophytic or exophytic growths. Also, positive C-kit expression was statistically higher in cases with optic nerve invasion (P = 0.001) and choroidal invasion (P ≤ 0.01) compared to negative cases. A highly significant positive VEGF expression was detected in cases with optic nerve invasion (P = 0.013) compared to negative cases. Moreover, a highly significant positive correlation was detected between C-kit and VEGF expression (P = 0.006). C-kit is a feature of more aggressive retinoblastomas, with increased expression in tumours spreading beyond the retina. Moreover, VEGF is vastly expressed in retinoblastoma and is associated with optic nerve invasion. Both C-kit and VEGF may represent potential therapeutic targets for retinoblastomas.
The present work deals with the benthic foraminiferal investigations and analyses of the Maastrichtian succession from two sections in the Kharga Oasis (Naqb El-Rufuf and Gabal Teir), to evaluate the ...prevailing paleobathymetric and paleoenvironmental conditions. Three benthic foraminiferal assemblages have been distinguished by the R-mode cluster analysis. The first two clusters are dominated by simple-walled and complex-walled non-calcareous agglutinated foraminifera, respectively; while the third assemblage is characterized by calcareous agglutinated and calcareous benthic foraminiferal species. The Q-mode Detrended Correspondence Analysis (DCA) of the studied samples indicates five main groups designated as five biofacies (IV), each with a characteristic faunal structure. The overall dominance of the non-calcareous agglutinated foraminifera and the sporadic occurrence of the calcareous benthic foraminifera suggest deposition in a shallow water environment of restricted brackish, lagoonal, and littoral setting with occasional marine incursions. The distribution of the identified benthic foraminiferal species suggests deposition under oxygen-depleted conditions with high organic matter flux. Surficial epifaunal taxa dominate the benthic assemblages at certain intervals suggesting episodes of stagnation and elevated position of the redox boundary relative to the water/sediment interface.
•This work deals with the benthic foraminifera of the Maastrichtian succession.•Three benthic foraminiferal assemblages have been recognized from the cluster analysis.•The non-calcareous agglutinated foraminifera dominate the benthic assemblages.•The prevailed paleoenvironmental conditions have been evaluated.
La nécrose rétinienne aiguë ou ARN syndrome est une affection d’origine virale appelée aussi « nécrose rétinienne herpétique », et bien que rare en fréquence, elle mérite d’être connue tant sa ...gravité compromettant le prognostic visuel. L’agent infectant est un virus du groupe herpès : herpès simplex (type 1 ou 2), herpès zoster (zona – varicelle) et cytomégalovirus (CMV). Elle se caractérise par une inflammation oculaire marquée, associée à une nécrose rétinienne d’extension progressive, de vascularite rétinienne et parfois d’atteintes extra oculaires. Le type d’atteinte occulaire depend à la fois du virus infectant et de l’état immunitaire du patient. La confirmation de ce diagnostic dès la découverte de la maladie par la réaction de polymérase en chaîne (PCR) et par le coefficient de charge immunitaire (CCI) le plus souvent par ponction d’humeur aqueuse permet d’optimiser la prise en charge. Le but du traitement est d’accélérer la résolution de l’infection dans l’œil infecté et de prévenir l’atteinte de l’œil controlatéral.
Il s’agit d’une patiente de 40 ans, sans antécédants pathologiques notables, en dehors d’un contact avec ses deux enfants qui avaient récemment contracté une varicelle. Le début de la symptomatologie était marqué par l’installation d’un syndrome grippal associé à des adénopathies sous maxillaires, et une toux productive, l’évolution fut marquée par l’apparition 5jours plus tard d’une rougeur au niveau de l’œil droit (OD), avec douleur, et baisse de l’acuité visuelle unilatéral. Traitée initialement comme conjonctivite virale, mais sans amélioration, avec une aggravation de la baisse de l’acuité visuelle. Un examen ophtalmologique avec fond d’œil et angiographie rétinienne ont permet de diagnostiquer une pan-uvéite granulomateuse unilatérale sévère de l’œil droit. La ponction de la chamber antérieure avec réalisation d’une PCR multiplex virale qui est revenue positive pour le VZV, négative pour HSV, et CMV.
L’angio-IRM cérébrale et occulo-orbitaire étaient sans anomalie en dehors d’une sinusite éthmoidale. Le diagnostic retenu était celui d’une nécrose rétinienne virale post-VZV de l’œil droit. La patiente a été mise sous traitement antiviral à base d’aciclovir par voie intraveineuse (IV)à la dose de 10mg/kg/8heures, associé à une corticothérapie par voie orale à la dose de 1mg/kg/jour, mais à J3 du traitement et suite à la perte brutale de la vision centrale de l’œil droit, un fond d’œil nous a permis de diagnostiquer une complication par décollement rétinien, qui a été opéré en urgence, avec injection de silicone pour réappliquer la rétine et réalisation d’un laser endo-oculaire. L’évolution sous traitement antiviral et après acte chirurgical était favorable, la rétine était totalement réappliquée avec des impacts de laser bien visible et sans zone de mal perfusion et d’ischémie. Les nécroplages de vascularite rétinienne se sont cicatrisées. L’angiographie à la fluorescéine a retrouvé une nette amélioration des signes inflammatoires. La vision est restée toujours basse mais avec une relative récupération de 1/10éme (OD), sous estimée en raison de la présence d’huile de silicone. Par ailleurs la nécrose rétinienne qui s’étendait de manière circonférentielle et centripète au niveau du pole postérieur sans l’atteindre, ce qui laisse présager la possibilité de récupération fonctionnelle après ablation d’huile de silicone. Par ailleurs l’examen régulier de l’œil gauche n’a pas objectivé de bilatéralisation.
Concernant le traitement médical, il a été décidé de poursuivre l’aciclovir (IV) pendant 5 semaines, avec relai par voie orale par le valaciclovir à la dose de 1g : 3 fois par jour pendant 6 semaines, puis entamer une dégression à la dose de 500mg : 3 fois par jours pendant 5 mois, en plus d’une dégression progressive de la dose de la corticothérapie sur 2 mois, avec une surveillance étroite.
Malgré la rareté du VZV dans les ARN, il semble l’agent infectant responsable de la rétinite nécrosante classique en cas d’immunocompétence et d’une tragique rétinite progressive compromettant le prognostic visuel. La rétinite à CMV constitue quant à elle une infection rétinienne opportuniste essentiellement associée au SIDA. Le diagnostic de ces rétinites est d’abord clinique et doit être évoqué devant toute panuvéite. Le traitement doit être instauré dans les plus brefs délais en raison du risque de bilatéralisation précoce et des complications rétiniennes.
Certaines de ces rétinites restent malheureusement résistantes au traitement et toujours dépendantes des efforts de recherche en vue d’améliorer leur pronostic.
A moment inequality is derived for new renewal better (worse) than used NRBU (NRWU) distributions which demonstrate that if the mean life is finite, then all moments exist. Next a new test statistics ...for testing exponentiality against NRBU (NRWU) is introduced based on this inequality. It is shown that the proposed test is simple and has high relative efficiency for some commonly used alternatives. Critical values are tabulated for sample sizes
n=5(1)50. A set of real data is used as an example to elucidate the use of the proposed test statistics for practical reliability analysis.
Standard reservoir evaluations are based on Archie's law relating the average water saturation to the average electrical resistivity by R(ind) = S(w)(-2). However, especially in the case of complex ...heterogeneous carbonates, deviation from Archie's law is observed and generally attributed to factors affecting the percolation or disconnectedness of the different phases (wetting films, microporosity, macropores) assuring electrical conductance. Pore-network models (PNM's) in combination with high-resolution computed microtomography (μ-CT) constitute a very effective tool to investigate the influence of the geometry and topology of the porous media on the spatial distribution of the conductive phase, and therefore on the shape of the resistivity index curve. An extended version of the classical PNM applicable to dual-porosity systems is presented. It combines the classical pore-network modeling applied on the macroporous space with the macroscopic properties of the microporous phase, supposing that the two pore systems act in parallel. Three-dimensional images provide information on the connectedness of the microporous phase, which is then included in the simulations. Electrical behavior of sandstone and two carbonates presenting distinct resistivity index curves were simulated and compared to measurements. Both Archie and "non-Archie" behavior were correctly reproduced, and the curve shape was explained considering percolation of the different phases.
Volatile oils from the leaves, flowers and rhizomes of
(Steud.) Sweet ex Klatt (Iridaceae) were analyzed using GLC/FID and GLC/MS. A total of 84 compounds were identified accounting for 94.65, 95.63 ...and 87.09% in the hydrodistilled oils from flowers, leaves and rhizomes, respectively. Spathulenol (48.44%) represented the major component in the leaf oil, followed by dihydro-edulan I (6.25%), cubenol (6.00%) and
-cadinol (5.90%). For the flower and rhizome oils, fatty acids, their esters, aliphatic hydrocarbons and their derivatives predominate. The antimicrobial activity of both leaf and flower oils was investigated against four bacteria in addition to four fungi using the micro-broth dilution method. The leaf oil showed a more potent antimicrobial activity as compared to the flower oil against most of the assessed bacteria and fungi, with higher activities against Gram- positive organisms showing MIC values of 115 and 460 μg/ml for
and
, respectively. Gram-negative bacteria were generally less susceptible (MIC > 2 mg/ml for both oils against
) and being completely ineffective against
. A relevant antifungal potency of the leaf oil against
and
was also observed with MIC values of 115 and 920 μg/ml, respectively.
To assess the role of aberrant miRNAs expressions in stage II CRC patients from Egypt.
Tumor tissue samples were obtained from 124 CRC stage II patients compared to 100 healthy controls for assessing ...miRNAs expression using; 1) a cataloged 84-miRNAs PCR array panel, and 2) another five miRNAs (miR-21, miR-137, miR-145, miR-320 and miR-498) that have been reported in previous studies to have a role in CRC, by quantitative real time PCR (qPCR). The results were correlated to patients' characteristics, response to treatment and survival.
There were 17 out of 84 miRNAs differentially expressed in the CRC patients. Twenty six miRNAs were significantly differentially expressed in the female CRC patients, while 16 miRNAs were significantly differentially expressed in the male CRC patients. Only, five miRNAs (miR-21, Let-7a-5p, miR-100-5p, miR-200c-3p and miR-23b-3p) were significantly common deregulated in CRC patients regardless gender. miR-21 was overexpressed in 48.4% of the patients and it was significantly downregulated in females and over expressed in males.
In univariate analysis; performance status, over-expression of miR-21 and miR-498 and reduced miR-137, miR-145, and miR-320 associated significantly with reduced DFS and OS whereas in multivariate analysis; miR-498 and miR-320 were independent prognostic factors for DFS and miR-21 was independent prognostic factors for OS.
miRNAs expression differs significantly between male and female stage II CRC patients, miR-21, Let-7a-5p, miR-100-5p, miR-200c-3p and miR-23b-3p could be used as common diagnostic biomarkers for CRC. On the other hand, a three miRNAs panel (miR-21, miR-498 and miR-320) can predict recurrence and survival in those patients.
Purpose: The aim of this study was to determine the preload and tensile fracture load values of prosthetic retaining screws after long‐term use in vivo compared to unused screws (controls). ...Additionally, the investigation addressed whether the preload and fracture load values of prosthetic retaining screws reported by the manufacturer become altered after long‐term use in vivo.
Materials and Methods: For preload testing, 10 new screws (controls) from Nobel Biocare (NB) and 73 used retaining screws 58 from NB and 15 from Sterngold (SG) were subjected to preload testing. For tensile testing, eight controls from NB and 58 used retaining screws (46 from NB and 12 from SG) were subjected to tensile testing. Used screws for both tests were in service for 18–120 months. A custom load frame, load cell, and torque wrench setup were used for preload testing. All 83 prosthetic screws were torqued once to 10 Ncm, and the produced preload value was recorded (N) using an X–Y plotter. Tensile testing was performed on a universal testing machine and the resulting tensile fracture load value was recorded (N). Preload and tensile fracture load values were analyzed with 2‐way ANOVA and Tukey post‐hoc tests.
Results: There was a significant difference between preload values for screws from NB and screws from SG (p < 0.001). The preload values for gold alloy screws from NB decreased as the number of years in service increased. There was a significant difference between tensile fracture values for the three groups (gold alloy screws from NB and SG and palladium alloy screws from NB) at p < 0.001. The tensile fracture values for gold alloy screws from NB and SG decreased as the number of years in service increased.
Conclusions: In fixed detachable hybrid prostheses, perhaps as a result of galling, the intended preload values of prosthetic retaining screws may decrease with increased in‐service time. The reduction of the fracture load value may be related to the increase of in‐service time; however, the actual determination of this relationship is not possible from this study alone.
Simplified explicit expressions are presented to describe the elastic displacement field of a periodic family of misfit dislocations running parallel to the two free surfaces of an elastically ...isotropic plate. In the situation where the period tends to infinity, the use of these expressions proves to be quite valuable for investigating the change of the separation distance, S, between two partial dislocations as a function of the position of one partial and the orientation of the fault plane. For the two 30° Shockley partials of a dissociated screw dislocation in an ultrathin silicon plate, numerical results indicate that S can change drastically. This property is confirmed in anisotropic elasticity for a dislocation located near the free surface of a semi-infinite crystal. The results emphasize that particular attention should be paid to precise measurement of the local thickness and positions of the partials in weak beam or high resolution transmission electron microscopy experiments.
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