Nanostructured implant surface effect on osteoblast gene expression and bone-to-implant contact in vivo

The aim of this study was to investigate the response of nanostructured implant surfaces at the level of osteoblast differentiation and its effects in bone-to-implant contact (BIC) and removal-torque values (RTV). CpTi grade IV implants (1.6 × 4.0 mm) were machined or machined and subsequently coated with an oxide solution. The surfaces were divided into: machined (M), titania-anatase (An), titania-rutile (Ru), and zirconia (Zr). Surfaces were examined by scanning electron microscopy, atomic force microscopy, and by X-ray microanalysis. Implants were inserted in rat tibia and harvested from 0 to 21 days for measurement of Alkaline Phosphatase, Bone Sialoprotein, Osteocalcin, Osteopontin, and RUNX-2 mRNA levels by real time PCR; from 0 to 56 days for RTV; and from 0 to 56 days for BIC. The roughness parameter (Sa) was compared by one-way ANOVA followed by Tukey Test. Comparison of Torque removal values and histomorphometric measurements on implants in vivo was performed by Kruskal–Wallis test and the significance level for all statistical analyses was set at p ≤ 0.05. mRNA levels on all nanostructured surfaces were increased compared to M. At 56 days, the mean RTV in Ncm was 11.6 ± 2.5, 11.3 ± 2.4, 11.1 ± 3.5, 9.7 ± 1.4 for An, Ru, Zr, and M, respectively. Higher BIC (%) was measured for all the nanostructured surfaces versus M at 21 and 56 days (p < 0.05). Nanostructured topographic features composed of TiO₂ or ZrO₂ applied to machined cpTi implant promoted greater mesenchymal stem cell commitment to the osteoblast phenotype and associated increased BIC and physical association with bone.     

A thermogravimetric study of the reaction between a crude-oil derivative and sulphur

Experiments conducted to investigate the reaction between a laboratory-prepared atmospheric residue (oil) and elemental sulphur are described. Results of the reaction between 10 and 50 wt% sulphur-in-oil mixtures, conducted on a thermogravimetric balance under controlled conditions of temperature and heating rate are presented. Data obtained from a batch reactor used to prepare a 2.0 kg batch of a 50/50 wt/wt mix is also included and analyses of products and residues are shown. The reaction, carried out at 473 K for a period of about 5 h, results in the loss of volatile reaction products in the first hour and of hydrogen sulphide and elemental sulphur continuously. The product yield increases with increased sulphur content in the original reaction mixture and is optimised at 50 wt% sulphur in oil. The chemical analyses indicate that the extent of reaction achieved by a 20 wt% sulphur-oil mixture is similar to that from a 50 wt% sulphur-oil mixture, but that fixation of carbon when the reaction product is heated to 873 K is strongly affected by the presence of the additional sulphur. Refluxing of condensed reaction products does not affect the final yield which is greater than 90% for a 50/50 sulphur-oil mixture. Nitrogen and carbon dioxide BET surface areas of the 873 K char, measured at 77 K and 192 K are 67.3 and 203.8 m² g⁻¹ respectively.     

Fabrication and characterisation of polypropylene nanofibres by meltblowing process using different fluids

In nonwoven industry, meltblowing has been widely used as an important technique for the production of nonwoven webs consisting of microfibres, suitable for various applications. Recently, great attention is being paid to fabricate nonwoven webs consisting of nanofibres, commonly known as nanowebs. In this paper, polypropylene has been successfully used for the fabrication of nanowebs by meltblowing process with the injection of different fluids (such as air and water) at the vent port of commercial meltblowing equipment. The lowest average fibre diameters achieved were 755 and 438 nm by the use of air and water, respectively. Differential scanning calorimetry results showed the presence of single melting peaks in the first heating cycle and double melting peaks in the second, due to the re-crystallisation and re-organisation by heating during the experiments. The results obtained from thermo gravimetric analysis and intrinsic viscosity studies showed thermal degradation of the nanofibres during meltblowing. X-ray diffraction studies showed that all the meltblown polypropylene fibres produced with the injection of the fluids contained low degrees of crystallinity and monoclinic α-form crystals. The crystallinity was increased with annealing. Similar Fourier transform infrared spectra of the polymer and the fibres indicated no change to the chemical functionality of the nanofibres by the application of the fluids and high temperature during meltblowing.     

Melt-electrospinning of polypropylene with conductive additives

In this paper, the feasibility of fabricating polypropylene (PP) nanofibres was investigated using conductive additives such as sodium oleate (SO) and sodium chloride (NaCl) during melt-electrospinning. PP of high melt flow index (MFI = 2000) was used with varying amounts of additives. The effects of amount of additives on the fibre diameter and morphology were investigated. The lowest fibre diameters of 0.371 ± 0.106 and 0.310 ± 0.102 μm were achieved with 7 % SO and 5 % NaCl, respectively. The fabrication of nanofibres was attributed to the increase in the electrical conductivity with the introduction of the additives. The increase in the electrical conductivity was greater in the case of NaCl, due to the smaller ionic size of NaCl. Differential scanning calorimetry results showed complex melting behaviour during the heating cycles for the fibres containing SO; and double melting peaks during the second heating cycle for the fibres containing NaCl. X-ray diffraction studies showed the fibres fabricated with the additives contained lower degrees of crystallinity compared to the as-spun fibre and the crystallinity was increased after annealing. The fibres fabricated with the additives contained α-form crystals only which did not change after annealing. The fibres fabricated from pure polymer and with the additives were hydrophobic in nature. The hydrophobicity was marginally decreased with the addition of SO and NaCl.     

Tear turnover rate is reduced in patients with symptomatic dry eye.

PURPOSE: Tear turnover rate (TTR) is defined as the percent decrease of fluorescein concentration in the tears per minute after the instillation of fluorescein. The purpose of this study was to examine differences in TTR in a sample with symptoms of dry eye and an asymptomatic control sample using the Fluorotron Master Fluorophotometer. METHODS: TTR was measured using the OcuMetrics Fluorotron Master. It measures the decay of the fluorescence of high molecular weight fluorescein FITC Dextran instilled into the tear film. Twenty participants (post-menopausal women) were enrolled in the study (10 asymptomatic (age 64.7 +/- 6.99) and 10 symptomatic (age 61.5 +/- 7.98)). Participants were grouped according to either a positive (symptomatic) or negative (asymptomatic) McMonnies Dry Eye Questionnaire, i.e., an indication of self-reported ocular dryness and the use of rewetting/lubricating drops (questions 4 and 5). TTR was measured in the afternoon only. Measurements were made on the right eye with a controlled blink rate (15 blinks/min), for up to 30 min, post-insertion of 2 microl of 2% FITC Dextran (MW 9500). The scan data were used to construct a graph of log fluorescein concentration (ng/ml) as a function of time and the TTR calculated (%/ min = (1- ln (slope)) x 100). RESULTS: There was a significant difference in the TTR between symptomatic and asymptomatic subjects. Mean TTR (symptomatic) was 4.89 +/-2.74%/min (range, 2.04-11.81) and mean TTR (asymptomatic) was 11.85 +/- 3.31%/min (range, 5.76-16.45) (P < 0.0001). CONCLUSIONS: Fluorophotometry may be used to demonstrate differences in the tear turnover rate in this post-menopausal group of women, with patients experiencing symptoms of dry eye having a lower TTR than the normals.     

Tear evaporation rates: What does the literature tell us?

Purpose

A previous literature review reported tear evaporation rates (TERs) from studies conducted on rabbits and humans between 1941 and 2003. Closer examination of the presented data revealed inaccuracies in the reporting of some values. This paper presents updated tables of TERs using values from the original papers cited in the review, in addition to incorporating new studies published between 2003 and 2016.

Surface versus bulk activity of lysozyme deposited on hydrogel contact lens materials in vitro

Purpose

To determine and compare the levels of surface versus bulk active lysozyme deposited on several commercially available hydrogel contact lens materials.

Women's knowledge of the leading causes of cancer death.

This paper describes adult women's knowledge of the leading causes of cancer mortality among women. Exposure to antismoking advertisements or media messages also is examined as a potentially effective mechanism for changing inaccurate beliefs. We used data from the 2002 and 2003 American Smoking and Health Survey (ASHES), a national telephone survey of adults, to measure women's knowledge about cancer mortality. Logistic regression models were used to estimate the likelihoods of women indicating either breast or lung cancer as the leading cause of cancer mortality among women. The independent influence of individual characteristics such as race, smoking status, education, and awareness of antismoking messages or advertising on women's knowledge of cancer mortality was assessed. Overall, 66.7% of women inaccurately indicated breast cancer as the leading cause of cancer death among women, whereas 29.7% of women correctly indicated lung cancer. Black women were 43% less likely than White women to indicate lung cancer as the leading cause of cancer mortality among women. Current smokers were 35% less likely than noncurrent smokers to state that lung cancer is the leading cause of cancer mortality among women. Awareness of antismoking messages or advertisements was associated with a higher probability of correctly indicating lung cancer as the leading cause of cancer mortality among women. Our evidence suggests that antismoking media messages may help to correct inaccurate beliefs about the leading causes of cancer death among women.     

Probabilistic Seismic Hazard Assessment for Jamaica

A probabilistic seismic hazard analysis was performed to generate seismic hazard maps for Jamaica. The analysis was then conducted using a standard logic-tree approach that allowed systematically taking into account the model-based （i.e., epistemic） uncertainty and its influence on the computed ground motion parameters. Hazard computations have been performed using a grid of sites with a space of 0.05 degrees. Two different computation methodologies have been adopted： the standard approach based on the definition of appropriate seismogenic sources and the zone-free approach, which overcomes the ambiguities related with the definition of the seismic sources solely reflecting the characteristics of the earthquake catalogue. A comprehensive and updated earthquake catalogue for Jamaica has been compiled for the years 1551-2010 and new empirical relationships amongst magnitudes Mze-Ms and Mw-mb have been developed for the region. Uniform hazard spectra and their uncertainty have been calculated for the horizontal component of ground motion for rock site conditions and five return periods （95, 475, 975, 2,475 and 4,975 years） and spectral accelerations for 34 structural periods ranging from 0 to 3 s, and 5% of critical damping. The spectral accelerations have been calculated to allow the definition of seismic hazard in Jamaica according to the International Building Code 2012. The disaggregation analysis for Kingston Metropolitan Area suggests that the magnitude-distance pair that contributes most to the hazard corresponds to events with M 7.8 and M 7.0 in the Enriquillo Plantain Garden Fault and the Jamaican Faults at a distance of 28 km and 18 km for short and long period structures respectively corresponding to 2,475 years return period. However, for long period structures, a substantial contribution is found for a M 8.2 at a distance of 198 km in the Oriente Fault Zone.