Diffusion profiles of high dosage Cr and V ions implanted into silicon

The depth profiles of high dosage Cr-52(+) and V-51(+) ions implanted in (100) crystalline silicon after thermal anneal at temperatures between 300 degreesC and 1000 degreesC are studied by secondary ion mass spectrometry and cross-sectional transmission electron microscopy. At dosages of 1x10(15) ions/cm(2) and above, the surface layer of silicon substrate is amorphorized. During the subsequent thermal annealing, the depth profiles of the implanted ions are strongly coupled with the solid phase epitaxial growth of amorphous silicon. Silicide precipitate formation is important to understand the differences between Cr and V diffusion. After anneal of the 1x10(15) ions/cm(2) implanted samples at 900 degreesC and 1000 degreesC, most of the Cr has left the silicon, but only 10% of the V has escaped. The 1x10(14) ions/cm(2) Cr-implanted sample shows Cr ions exist only near the surface after 1000 degreesC anneal. The V-implanted sample, on the other hand, only shows a narrowing of the V profile after 1000 degreesC anneal

Physical and biological characterization of ferromagnetic fiber networks: effect of fibrin deposition on short-term in vitro responses of human osteoblasts.

Ferromagnetic fiber networks have the potential to deform in vivo imparting therapeutic levels of strain on in-growing periprosthetic bone tissue. 444 Ferritic stainless steel provides a suitable material for this application due to its ability to support cultures of human osteoblasts (HObs) without eliciting undue inflammatory responses from monocytes in vitro. In the present article, a 444 fiber network, containing 17 vol% fibers, has been investigated. The network architecture was obtained by applying a skeletonization algorithm to three-dimensional tomographic reconstructions of the fiber networks. Elastic properties were measured using low-frequency vibration testing, providing globally averaged properties as opposed to mechanical methods that yield only local properties. The optimal region for transduction of strain to cells lies between the ferromagnetic fibers. However, cell attachment, at early time points, occurs primarily on fiber surfaces. Deposition of fibrin, a fibrous protein involved in acute inflammatory responses, can facilitate cell attachment within this optimal region at early time points. The current work compared physiological (3 and 5 g·L(-1)) and supraphysiological fibrinogen concentrations (10 g·L(-1)), using static in vitro seeding of HObs, to determine the effect of fibrin deposition on cell responses during the first week of cell culture. Early cell attachment within the interfiber spaces was observed in all fibrin-containing samples, supported by fibrin nanofibers. Fibrin deposition influenced the seeding, metabolic activity, and early stage differentiation of HObs cultured in the fibrin-containing fiber networks in a concentration-dependant manner. While initial cell attachment for networks with fibrin deposited from low physiological concentrations was similar to control samples without fibrin deposition, significantly higher HObs attached onto high physiological and supraphysiological concentrations. Despite higher cell numbers with supraphysiological concentrations, cell metabolic activities were similar for all fibrinogen concentrations. Further, cells cultured on supraphysiological concentrations exhibited lower cell differentiation as measured by alkaline phosphatase activity at early time points. Overall, the current study suggests that physiological fibrinogen concentrations would be more suitable than supraphysiological concentrations for supporting early cell activity in porous implant coatings.This is the author accepted manuscript. The final version is available from Mary Ann Liebert at http://online.liebertpub.com/doi/abs/10.1089/ten.TEA.2014.0211?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed

Application of Tribology Concept in Dental Composites Field: A Scoping Review

Tribology is the discipline concerning the application of friction, lubrication, and wear concepts of interacting surfaces in relative motion. A growing interest has developed in tribology application in medical biomaterials, such as resin composites used in restorative dentistry. Yet, the keywords “tribology” and “biotribology” are little applied in the pertinent publications. The aim of this scoping review was to offer an overview of tribology application in dental composites research and to identify knowledge gaps and address future research. A literature search was conducted on Pubmed and Scopus databases and the studies investigating the tribological behavior of resin composites were included for qualitative synthesis. The majority of studies on dental tribology were published in the research areas of mechanical engineering/nanotechnology and differed in several methodological aspects. The preponderant engineering approach and the lack of standardized testing make the laboratory findings poorly informative for clinicians. Future research should focus on the tribological behavior of dental materials composites by means of an integrated approach, i.e., engineering and clinical, for improving development and advancement in this field of research

Step-Indexed Normalization for a Language with General Recursion

The Trellys project has produced several designs for practical dependently typed languages. These languages are broken into two fragments-a_logical_fragment where every term normalizes and which is consistent when interpreted as a logic, and a_programmatic_fragment with general recursion and other convenient but unsound features. In this paper, we present a small example language in this style. Our design allows the programmer to explicitly mention and pass information between the two fragments. We show that this feature substantially complicates the metatheory and present a new technique, combining the traditional Girard-Tait method with step-indexed logical relations, which we use to show normalization for the logical fragment.Comment: In Proceedings MSFP 2012, arXiv:1202.240

“What does that mean?":The content validity of the ISPCAN Child Abuse Screening Tool - Child version (ICAST-C) in Romania, South Africa, and the Philippines

Background: The International Society for Prevention of Child Abuse and Neglect (ISPCAN) Child Abuse Screening Tool (Children\u27s Version), known as the ICAST-C Version 3, is used widely to assess violence against children, but there is limited psychometric evidence, especially on content validity. Objective: This study aimed to assess the content validity of the ICAST-C with adolescents in Romania, South Africa, and the Philippines. Methods: A purposive sample of adolescents (N = 53, 51 % female) were recruited from urban areas in Romania, the Eastern Cape Province of South Africa, and Metro Manila, Philippines. Semi-structured one-on-one in-depth cognitive interviews sought adolescent perspectives on the relevance, comprehensibility, and comprehensiveness of the ICAST-C. Data were analysed using template analysis. Results: The ICAST-C was broadly perceived to be relevant and comprehensive in measuring violence against children in all study locations. However, there were issues with the comprehensibility of the measure, described at three levels: interpreting items, undertaking coherent elaborations of relevant behaviors and places, and generating a coherent response to the questions. Conclusions: Suggestions to revise the ICAST-C include, among others, adding a practice or how-to section on answering the survey, clarifying the intent of questions, especially on neglect and sexual abuse, emphasizing that questions cover all locations, and asking more positive questions. Pilot studies testing the content validity and cultural appropriateness are needed as a matter of practice in large self-report surveys

What does that mean? : The content validity of the ISPCAN Child Abuse Screening Tool - Child version (ICAST-C) in Romania, South Africa, and the Philippines

Background: The International Society for Prevention of Child Abuse and Neglect (ISPCAN) Child Abuse Screening Tool (Children\u27s Version), known as the ICAST-C Version 3, is used widely to assess violence against children, but there is limited psychometric evidence, especially on content validity. Objective: This study aimed to assess the content validity of the ICAST-C with adolescents in Romania, South Africa, and the Philippines. Methods: A purposive sample of adolescents (N = 53, 51 % female) were recruited from urban areas in Romania, the Eastern Cape Province of South Africa, and Metro Manila, Philippines. Semi-structured one-on-one in-depth cognitive interviews sought adolescent perspectives on the relevance, comprehensibility, and comprehensiveness of the ICAST-C. Data were analysed using template analysis. Results: The ICAST-C was broadly perceived to be relevant and comprehensive in measuring violence against children in all study locations. However, there were issues with the comprehensibility of the measure, described at three levels: interpreting items, undertaking coherent elaborations of relevant behaviors and places, and generating a coherent response to the questions. Conclusions: Suggestions to revise the ICAST-C include, among others, adding a practice or how-to section on answering the survey, clarifying the intent of questions, especially on neglect and sexual abuse, emphasizing that questions cover all locations, and asking more positive questions. Pilot studies testing the content validity and cultural appropriateness are needed as a matter of practice in large self-report surveys

Removal of gutta-percha/zinc-oxide-eugenol sealer or gutta-percha/epoxy resin sealer from severely curved canals: An in vitro study

The aim of this study was to compare the cleanliness of root canal walls after retreatment using two rotary retreatment files to hand instruments in severely curved canals obturated with gutta-percha and two different sealers. Single rooted mandibular premolars (n = 90) with root curvatures were instrumented and obturated with gutta-percha and an epoxy resin (Group 1, n = 45) or zinc oxide eugenol sealer (Group 2, n = 45). Following retreatment of the specimens (n = 15 ProTaper Universal Retreatment Files (Subgroup B) or R-Endo retreatment files (Subgroup C) after 1 month, split specimens were examined under a stereomicroscope and the percentage of remaining root filling material was statistically compared using one way ANOVA with Bonferroni adjustment for multiple comparisons (P = 0.05). The R-Endo system performed significantly better than the other two file systems (P < 0.05). None of the systems used in this study cleaned root canals thoroughly. The R-Endo system did provide cleaner walls when compared to the other instruments used. The type of root filling materials had an impact on the outcomes with all techniques. Copyright © 2011 Santhoshini Reddy et al.Link_to_subscribed_fulltex

Diagnostic Performance of Optical Coherence Tomography Ganglion Cell–Inner Plexiform Layer Thickness Measurements in Early Glaucoma

PURPOSE: To evaluate the glaucoma diagnostic performance of ganglion cell inner-plexiform layer (GCIPL) parameters used individually and in combination with retinal nerve fiber layer (RNFL) or optic nerve head (ONH) parameters measured with Cirrus HD-OCT (Carl Zeiss Meditec, Inc, Dublin, CA). DESIGN: Prospective cross-sectional study. PARTICIPANTS: Fifty patients with early perimetric glaucoma and 49 age-matched healthy subjects. METHODS: Three peripapillary RNFL and 3 macular GCIPL scans were obtained in 1 eye of each participant. A patient was considered glaucomatous if at least 2 of the 3 RNFL or GCIPL scans had the average or at least 1 sector measurement flagged at 1% to 5% or less than 1%. The diagnostic performance was determined for each GCIPL, RNFL, and ONH parameter as well as for binary or-logic and and-logic combinations of GCIPL with RNFL or ONH parameters. MAIN OUTCOME MEASURES: Sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR). RESULTS: Among GCIPL parameters, the minimum had the best diagnostic performance (sensitivity, 82.0%; specificity, 87.8%; PLR, 6.69; and NLR, 0.21). Inferior quadrant was the best RNFL parameter (sensitivity, 74%; specificity, 95.9%; PLR, 18.13; and NLR, 0.27), as was rim area (sensitivity, 68%; specificity, 98%; PLR, 33.3; and NLR, 0.33) among ONH parameters. The or-logic combination of minimum GCIPL and average RNFL provided the overall best diagnostic performance (sensitivity, 94%; specificity, 85.7%; PRL, 6.58; and NLR, 0.07) as compared with the best RNFL, best ONH, and best and-logic combination (minimum GCIPL and inferior quadrant RNFL; sensitivity, 64%; specificity, 100%; PLR, infinity; and NPR, 0.36). CONCLUSIONS: The binary or-logic combination of minimum GCIPL and average RNFL or rim area provides better diagnostic performances than those of and-logic combinations or best single GCIPL, RNFL, or ONH parameters. This finding may be clinically valuable for the diagnosis of early glaucoma

3-Phenylcoumarins as Inhibitors of HIV-1 Replication

We have synthesized fourteen 3-phenylcoumarin derivatives and evaluated their anti-HIV activity. Antiviral activity was assessed on MT-2 cells infected with viral clones carrying the luciferase gene as reporter. Inhibition of HIV transcription and Tat function were tested on cells stably transfected with the HIV-LTR and Tat protein. Six compounds displayed NF-κB inhibition, four resulted Tat antagonists and three of them showed both activities. Three compounds inhibited HIV replication with IC50 values < 25 μM. The antiviral effect of the 4-hydroxycoumarin derivative 19 correlates with its specific inhibition of Tat functions, while compound 8, 3-(2-chlorophenyl)coumarin, seems to act through a mechanism unrelated to the molecular targets considered in this research

Antiviral Activity of the Hepatitis C Virus Polymerase Inhibitor Filibuvir in Genotype 1-Infected Patients

More effective and better-tolerated therapies are needed for chronic hepatitis C virus (HCV) infection. Among the direct-acting anti-HCV agents in development is the nonstructural 5B protein (NS5B polymerase) non-nucleoside inhibitor filibuvir. We investigated the antiviral activity, pharmacokinetics, safety, and tolerability of multiple doses of filibuvir in treatment-naive and treatment-experienced patients who were chronically infected with HCV genotype 1 in two phase 1b clinical studies (study 1 was a randomized, placebo-controlled dose escalation study and study 2 was a nonrandomized, open-label study). The filibuvir doses evaluated ranged from 200-1400 mg daily, and the duration of dosing ranged from 3-10 days. Genotypic changes in the NS5B nucleotide sequence following short-term filibuvir therapy were also assessed. Filibuvir potently inhibited viral replication in a dose-dependent manner. Mean maximum HCV RNA change from baseline ranged from 20.97 log 10 IU/mL with filibuvir given at 100 mg twice daily to 22.30 log 10 IU/mL with filibuvir given at 700 mg twice daily in treatment-naive patients. In treatmentexperienced patients, an HCV RNA reduction of 2.20 log 10 IU/mL was achieved with filibuvir given at 450 mg twice daily. Filibuvir was well tolerated in both studies. Adverse events were mild or moderate in severity. No discontinuations, serious adverse events, or deaths were reported. NS5B sequencing identified residue 423 as the predominant site of mutation after filibuvir dosing. Conclusion: Filibuvir administration resulted in significant reductions in HCV RNA concentrations at doses that were well tolerated in patients infected with HCV genotype 1. Filibuvir is currently being evaluated in combination with pegylated interferon alfa 2a plus ribavirin in treatment-naive patients. (HEPATOLOGY 2011;54:50-59) and is a leading cause of chronic liver disease. 2 The current standard of care for chronic HCV infection is a combination of pegylated interferon alfa (pegIFN) and ribavirin (RBV). 3 In treatment-naive patients who are infected with HCV genotype 1, administration of pegIFN and RBV results in a sustained virological response (SVR; defined as undetectable HCV RNA in the plasma 24 weeks after completion of therapy) in only 40%-50% of patients following 48 weeks of therapy. 7 PegIFN and RBV therapy is also associated with substantial side effects, including fatigue