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Urban conurbations of East Africa are affected by harmful levels of air pollution. The paucity of local air quality networks and the absence of the capacity to forecast air quality make difficult to quantify the real level of air pollution in this area. The CHIMERE chemistry transport model has been used along with the Weather Research and Forecasting (WRF) meteorological model to run high-spatial-resolution (2 × 2 km) simulations of hourly concentrations of particulate matter with an aerodynamic diameter smaller than 2.5 µm (PM2.5) for three East African urban conurbations: Addis Ababa in Ethiopia, Nairobi in Kenya, and Kampala in Uganda. Two existing emission inventories were combined to test the performance of CHIMERE as an air quality model for a target monthly period in 2017, and the results were compared against observed data from urban, roadside, and rural sites. The results show that the model is able to reproduce hourly and daily temporal variabilities in aerosol concentrations that are close to observed values from urban, roadside, and rural environments. CHIMERE's performance as a tool for managing air quality was also assessed. The analysis demonstrated that, despite the absence of high-resolution data and up-to-date biogenic and anthropogenic emissions, the model was able to reproduce 66 %–99 % of the daily PM2.5 exceedances above the World Health Organization (WHO) 24 h mean PM2.5 guideline (25 µg m−3) in the three cities. An analysis of the 24 h average PM2.5 levels was also carried out for 17 constituencies in the vicinity of Nairobi. This showed that 47 % of the constituencies in the area exhibited a poor Air Quality Index for PM2.5 that was in the unhealthy category for human health, thereby exposing between 10 000 and 30 000 people per square kilometre to harmful levels of air contamination.

This study explores novel solutions other than standard SBF for biomimetic evaluations of mineralization particularly for resin composites containing bioactive glass (BAG).Experimental UDMA/TEGDMA resin composites with 0.0, 1.9, 3.8 or 7.7 vol% of 45S5 BAG fillers were prepared. Besides simulated body fluid (SBF) as control, the specimens were immersed in three other solutions either with bicarbonate which are Hank's balanced salt solution (HBSS) and cell culture medium (MEM), or without bicarbonate which is a novel Simple HEPES-containing Artificial Remineralization Promotion (SHARP) solution, for 3, 7 and 14 days. These solutions were then analyzed by ICP-OES and pH meter, and the surfaces of the BAG composites were analyzed by SEM, XRD and FTIR.ICP-OES revealed Ca and P concentration continuously decrease, while Si concentration increases with time in the solutions other than SBF, which showed almost unchanged elemental concentration. Only SHARP solution is able to maintain a constant pH over the immersion time. SEM, together with XRD and FTIR, showed nano-sized octacalcium phosphate (OCP) nanospheres formation on 3.8 and 7.7 vol% BAG composites after 14 days immersion in HBSS (500-600 nm) and MEM (300-400 nm). SHARP solution enabled OCP formation after 3 days and then self-assembled into urchin-like carbonated hydroxyapatite (CHA) microspheres encompassed with nanorods of 100 nm width and 8 µm length after 14 days of immersion for 7.7 vol% BAG composites.This study suggests SHARP solution can evaluate mineralization biomimetically whereas CHA microspheres can be formed on BAG-containing resin composites.

This study compared the surface gloss (SG), gloss retention (GR), and color stability (CS) of 2 universal resin composites after chemical (CA) and mechanical (MA) aging.Twenty disc-shaped samples of G-ænial A´Chord (GC-Europe) and Filtek Universal (3M-ESPE) were polished with sequential abrasive papers. For CA, specimens were stored in 1 mL of 75% ethanol for 15 days at 37°C, and readings (SG, GR, and CS) were obtained at baseline and 5, 10, and 15 days. For MA, specimens were subjected to 10,750 simulated brushing cycles. SG and CS were evaluated after every 3,583 cycles. SG was measured with a glossmeter (geometrical configuration: 60°), and values were expressed in gloss units. Color was measured with a spectrophotometer using the CIE-L*a*b* color system. The Student'sG-ænial presented significantly higher SG values than Filtek (G-ænial presented higher SG values and better CS. Both restorative materials demonstrated acceptable GR and CS. Aging protocols impacted these properties negatively.

Urban conurbations of East Africa are affected by harmful levels of air pollution. The paucity of local air quality networks and the absence of capacity to forecast air quality make it difficult to quantify the real level of air pollution in this area. The chemistry-transport model CHIMERE has been coupled with the meteorological model WRF and used to simulate hourly concentrations of Particulate Matter PM2.5 for three East African urban conurbations: Addis Ababa in Ethiopia, Nairobi in Kenya and Kampala in Uganda. Two existing emission inventories were combined to test the performance of CHIMERE as an air quality tool for a target monthly period of 2017 and the results compared against observed data from urban and rural sites. The results show that the model is able to reproduce hourly and daily temporal variability of aerosol concentrations close to observations both in urban and rural environments. CHIMERE’s performance as a tool for managing air quality was also assessed. The analysis demonstrated that despite the absence of high-resolution data and up-to-date biogenic and anthropogenic emissions, the model was able to reproduce 66–99 % of the daily PM2.5 exceedances above the WHO 24-hour mean PM2.5 guideline (25 µg m−3) in the three cities. An analysis of the 24-hour mean levels of PM2.5 was also carried out for 17 constituencies in the vicinity of Nairobi. This showed that 47 % of the constituencies in the area exhibited a low air quality index for PM2.5 in the unhealthy category for human health exposing between 10000 to 30000 people/km2 to harmful levels of air contamination.

Objective To describe clinical and pathologic findings from cases of in-the-bag capsular tension ring (CTR) and intraocular lens (IOL) subluxation or dislocation. Design Retrospective case series with clinicopathologic correlation. Participants Twenty-three explanted subluxated/dislocated capsular bags containing a CTR and an IOL explanted in Europe and submitted in fixative to the Berlin Eye Research Institute. Methods Standard gross and light microscopy of specimens, complete histopathologic analyses of selected specimens done at the University of Utah, as well as questionnaire sent to explanting surgeons, and patient chart review, when available. Main Outcome Measures Lens design, material, and abnormalities, capsular bag anomalies, patient demographic data, surgical dates, and presence or absence of known risk factors. Results Patients were aged 76.31±8.24 years at explantation, which was performed 81.5±32.2 months after implantation. The IOLs in these cases were 3-piece hydrophobic acrylic (N = 11), 1-piece hydrophobic acrylic (n = 6), 3-piece silicone (n = 4), or 1-piece hydrophilic acrylic (n = 2) designs; all CTRs were made of poly(methyl methacrylate). Available information on associated ocular conditions included pseudoexfoliation (n = 17), glaucoma (n = 4), vitrectomy/retina surgery (n = 3), and trauma (n = 1). Complete histopathologic assessment in 3 specimens showed signs consistent with pseudoexfoliation, without available history related to this condition in one of the cases. Moderate/severe degrees of Soemmering's ring formation and capsulorhexis phimosis were observed or reported in 13 and 11 specimens, respectively. Fourteen eyes were implanted and explanted by the same surgeon, with an interval of 92.7±23.4 months between the procedures. His rate of explantation because of subluxation/dislocation was 0.76% of the CTRs implanted during the time considered. Conclusions Explantation because of postoperative subluxation or dislocation of CTR–IOL–capsular bag complexes occurred approximately 6.8 years after implantation in this series, providing further evidence that a fine line exists between zonular insufficiency that can be stabilized with the CTR alone and that requiring further support. Analyses of large series may help to define common factors associated with this complication, as well as surgical planning and employment of various endocapsular support devices to enhance postoperative zonular stabilization. Financial Disclosure(s) The authors have no proprietary or commercial interest in any materials discussed in this article.

Purpose To assess capsular bag opacification and sites of initial posterior capsule opacification (PCO) in human cadaver eyes with square-edged 1-piece or 3-piece hydrophobic acrylic intraocular lenses (IOLs). Setting John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Design Experimental study. Methods Eyes were immersed in 10% formalin after enucleation and had anterior segment scanning with very-high-frequency ultrasound (Artemis). After the eyes were sectioned at the equator, gross examination of the anterior segment was performed from the posterior aspect to assess capsular bag opacification, anterior capsule coverage of the IOL edge, and IOL fixation. Selected eyes had histopathologic examination. Results One hundred nineteen eyes with 1-piece IOLs and 100 with 3-piece IOLs were included in the analyses of capsular bag opacification. There was no difference in central ( P =.29) or peripheral ( P =.76) PCO. In 63 of 84 eyes with a 1-piece IOL and peripheral PCO, the optic–haptic junction was the site of initiation. In eyes with a 3-piece IOL, initial peripheral PCO was observed at nearly the same rate whether there was full 360-degree anterior capsulorhexis overlap of the optic or no overlap ( P =.13). In the latter, the site of PCO initiation was in areas lacking capsulorhexis coverage in 46% of eyes. Conclusions There was no difference in central or peripheral PCO between 1-piece and 3-piece hydrophobic acrylic IOLs. With 1-piece IOLs, PCO tended to start at the optic–haptic junctions. With 3-piece IOLs, full anterior capsule coverage did not produce a statistically significant benefit with respect to PCO prevention. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

To determine whether a hydrogel liquid ocular bandage improves wound strength.John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.Laboratory investigation.The wound strength of 2.8 mm clear corneal incisions and 23-gauge scleral incisions was tested in cadaver eyes by raising the intraocular pressure (IOP) until leakage occurred. The pressure at the first sign of incision leakage with the liquid bandage and without the liquid bandage was determined.Four corneal incisions and 4 scleral incisions were made in 5 cadaver eyes. The mean pressure at the first sign of corneal incision leakage was 59.5 mm Hg ± 21.0 (SD) without the liquid bandage and 198.1 ± 57.6 mm Hg with the liquid bandage (P.0001). The mean pressure at the first sign of scleral incision leakage was 47.9 ± 21.4 mm Hg and 209.0 ± 42.9 mm Hg, respectively (P.0001). Eight corneal incisions and 8 scleral incisions did not leak at the maximum pressure of 246 mm Hg. With both incision types, the difference in leakage with a liquid bandage in place and with no liquid bandage was statistically significant (P = .002).With application of a hydrogel liquid ocular bandage, incisions withstood significantly higher IOP before leakage occurred than when no liquid bandage was used.

We describe 2 cases in which patients with 4-looped single-piece hydrophilic acrylic intraocular lenses (IOLs) exhibited postoperative complications including capsulorhexis phimosis, decentration, tilt, hyperopic shift, and luxation leading to explantation of the IOL–capsular bag complex. The excessive capsule fibrosis led to anterior flexing of the IOL haptics in both cases, even in the presence of a capsular tension ring (CTR). Histopathological analyses revealed a thick fibrocellular tissue attached to the inner surface of the anterior capsules, corresponding to the anterior capsule opacification and folds. An amorphous substance was observed on the outer surface of the anterior capsule in the case with a CTR, suggesting pseudoexfoliation material. These and similar cases raise concerns about the postoperative behavior of highly flexible IOLs in the presence of excessive capsular bag fibrosis. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Falsework collapses are no longer common in the UK following publication of national falsework standard BS 5975 in 1982. However, this seems more due to under-loading of modern falsework systems than the industry's ability to erect them properly. A survey three years ago of 11 UK construction sites revealed lack of verticality of uprights has changed little since a previous survey 12 years earlier. However, though two sites failed the British standard, all passed the new European standard, EN 12812. This paper summarises the findings of the survey and highlights the risk of imposing a full ‘safe working load’ on falsework given current industry practice and the recent introduction of more relaxed rules.

Enactment of China’s new Enterprise Income Tax Law was announced on March 16 2007 (with effect from January 1 2008). The Enterprise Income Tax Law potentially increased the tax burden on foreign-invested enterprises (FIEs) and foreign investors as a whole (removing concessions), potentially lowering the tax burden for domestic companies (a fall in the nominal tax rate from 33 per cent to 25 per cent). The announcement of such significant changes to corporate tax arrangements provides a natural ‘experimental platform’ for research on the impact of regulatory change in a transition economy and developing capital market. This study uses the event study method to investigate the relationship between corporate tax aggressiveness and stock price reactions to the announcement of the new Enterprise Income Tax Law. To account for key features of China’s stock markets and corporate behavior, we address the impact of ownership structure, particularly high levels of state and foreign ownership, and differences in the regulatory environment between China’s Shanghai and Shenzhen stock markets. We conclude that the announcement of the Enterprise Income Tax Law had significant market value effects. Additionally, we find variations in market reaction for individual stocks based on tax aggressiveness, ownership, and location of listing.

This study uses the 'natural experiment' provided by China's implementation of its 2007 Accounting Standards for Business Enterprises No.18 - Corporate Income Tax Accounting and 2008 Enterprise Income Tax Law to address two questions. Have China's tax regulatory environment changes had an impact on the corporate tax avoidance of its listed companies? Does ownership structure - i.e., state-controlled, private or foreign-invested - impact on companies' responses to regulatory change? Drawing on effective tax planning, agency, tax avoidance and legitimacy theories, this study uses a balanced panel-data sample for the 2007 to 2010 period on 1,224 companies listed on the Shanghai and Shenzhen Stock Exchanges. We find that tax avoidance by listed companies, measured by the book-tax gap, has reduced as a result of regulatory reform. Additionally we tentatively support the influence of ownership/control on corporate tax avoidance in China, with state-controlled companies evidencing lower levels of the book tax gap. Refereed/Peer-reviewed

This review paper firstly provides an outline of the development of resin-based adhesives. A simple classification method is described based on whether an acid etching agent requiring a washing and drying step is used. These systems are called etch and rinse systems. The other adhesives that do not have the washing and drying steps are referred to as self-etching adhesives. The advantages and disadvantages of these groups of adhesives are discussed. Methods of adhering to the tooth surface are provided, especially where the resin-based adhesive reliability is difficult to control.

Purpose To evaluate the influence of trypan blue staining on capsulorhexis tear resistance using a model for mechanical measurement of the entire capsular bag of fresh human cadaver eyes. Setting John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Design Experimental study. Methods After the cornea and iris were removed, a 5.0 to 5.5 mm anterior continuous curvilinear capsulorhexis (CCC) was created; the capsule in study eyes was stained with trypan blue. The nucleus was hydroexpressed and the capsular bag was evacuated by irrigation/aspiration. Two metal shoetree-shaped fixtures were implanted separately in the capsular bag and assembled using a screw nut. After zonulectomy, the fixture–capsular bag assembly was removed from the eye and loaded onto a mechanized tester. The fixtures were separated at a velocity of 7.0 mm/min in 0.15 μm intervals to stretch the capsulorhexis to its rupture point. A graph was generated for each eye. Results Ten study eyes were compared with 23 control eyes. The groups were comparable in donor age, time from death, and CCC diameter. The mean rupture load was 0.40 Newton (N) ± 0.13 (SD) in the trypan blue group and 0.39 ± 0.16 N in the control group ( P =.94). The mean extension was 5.70 ± 0.99 mm and 5.85 ± 1.17 mm, respectively ( P =.74). Conclusions There was no difference in CCC strength between trypan blue–stained capsules and control capsules. Staining with trypan blue did not reduce CCC tear resistance. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

To describe clinical and pathologic findings from cases of in-the-bag capsular tension ring (CTR) and intraocular lens (IOL) subluxation or dislocation.Retrospective case series with clinicopathologic correlation.Twenty-three explanted subluxated/dislocated capsular bags containing a CTR and an IOL explanted in Europe and submitted in fixative to the Berlin Eye Research Institute.Standard gross and light microscopy of specimens, complete histopathologic analyses of selected specimens done at the University of Utah, as well as questionnaire sent to explanting surgeons, and patient chart review, when available.Lens design, material, and abnormalities, capsular bag anomalies, patient demographic data, surgical dates, and presence or absence of known risk factors.Patients were aged 76.31 ± 8.24 years at explantation, which was performed 81.5 ± 32.2 months after implantation. The IOLs in these cases were 3-piece hydrophobic acrylic (N = 11), 1-piece hydrophobic acrylic (n = 6), 3-piece silicone (n = 4), or 1-piece hydrophilic acrylic (n = 2) designs; all CTRs were made of poly(methyl methacrylate). Available information on associated ocular conditions included pseudoexfoliation (n = 17), glaucoma (n = 4), vitrectomy/retina surgery (n = 3), and trauma (n = 1). Complete histopathologic assessment in 3 specimens showed signs consistent with pseudoexfoliation, without available history related to this condition in one of the cases. Moderate/severe degrees of Soemmering's ring formation and capsulorhexis phimosis were observed or reported in 13 and 11 specimens, respectively. Fourteen eyes were implanted and explanted by the same surgeon, with an interval of 92.7 ± 23.4 months between the procedures. His rate of explantation because of subluxation/dislocation was 0.76% of the CTRs implanted during the time considered.Explantation because of postoperative subluxation or dislocation of CTR-IOL-capsular bag complexes occurred approximately 6.8 years after implantation in this series, providing further evidence that a fine line exists between zonular insufficiency that can be stabilized with the CTR alone and that requiring further support. Analyses of large series may help to define common factors associated with this complication, as well as surgical planning and employment of various endocapsular support devices to enhance postoperative zonular stabilization.

Purpose To evaluate the stability and capsular bag opacification with a modified disk-shaped 1-piece hydrophilic acrylic intraocular lens (IOL) suspended between 2 complete haptic rings connected by a pillar of the haptic material and with a commercially available 1-piece hydrophilic acrylic IOL. Setting John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Design Experimental study. Methods Study and control IOLs were implanted into the left eyes and right eyes of 5 New Zealand rabbits. Eyes were examined at the slitlamp from 1 through 4 weeks. At 4 weeks, the globes were enucleated and evaluated under a very-high-frequency ultrasound. Photographs were taken and capsular bag opacification scored from the posterior aspect (Miyake-Apple view), and the eyes were processed for complete histopathology. Results At 4 weeks, the posterior capsule opacification score was 0.0 in the study group and 1.75 ± 0.5 (SD) in the control group ( P =.005, paired t test). Ultrasound examination showed that 2 of the study IOLs had no contact between the posterior optic surface and the posterior capsule. Minimal proliferative cortical material was confined to the peripheral space between anterior and posterior rings of the study IOL haptics in localized areas at the equatorial region of the capsular bag. Anterior capsule opacification was absent in all eyes. Conclusions The study IOL is a modification of a previous design, incorporating haptic perforations between the peripheral rings. By maintaining an open capsular bag and enhancing endocapsular inflow of aqueous, this modified design appears to prevent capsular bag opacification. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

To assess the degree of capsular bag opacification in human cadaver eyes with silicone intraocular lenses (IOLs), specifically comparing the differences between round-edged IOLs and modern square-edged IOLs.John A. Moran Eye Center, University of Utah, USA.Experimental study.The eyes were immersed in 10% formalin on enucleation. They had anterior segment scanning with a very-high-frequency ultrasound (Artemis). After the eyes were sectioned at the equator, gross examination of the anterior segment was performed from the posterior aspect to assess the degree of capsular bag opacification, coverage of the IOL edge by the anterior capsule, and IOL fixation. Selected eyes also had histopathologic examination.Eighty-seven eyes with a 3-piece round-edged IOL, 43 with a 3-piece square-edged IOL, 26 with a 1-piece plate IOL, and 1 with an accommodating IOL design were included in the analyses of capsular bag opacification. Comparison between 3-piece round-edged IOLs and square-edged IOLs showed statistically significant differences in central posterior capsule opacification (PCO) (P=.0001687) and peripheral PCO (P.0001). In eyes with square-edged IOLs, PCO had a tendency to start in areas without capsulorhexis coverage of the optic. Twenty-one of 26 eyes with a silicone plate IOL had a neodymium:YAG posterior capsulotomy for dense PCO.This first study using pseudophakic human cadaver eyes that includes a significant number of modern 3-piece silicone IOLs with square optic edges confirmed the role of this design in the prevention of PCO.No author has a financial or proprietary interest in any material or method mentioned.

We analyzed an enucleated postmortem eye from an 86-year-old donor who had a 2-loop iridocapsular intraocular lens (IOL) that had been implanted at least 30 years earlier. High-frequency ultrasound showed a relatively well-centered iris-supported optic in front of the pupil. Gross and light microscopic analyses of the eye and the IOL showed loop fixation outside the capsular bag remnants, a thickened cornea, mild attenuation of the corneal endothelium, multiple areas of iris trauma secondary to haptic abrasion, fragments of iris tissue attached to the haptics, as well as pigment dispersion within the eye with pigmented epithelial cells attached to the IOL haptics. Histopathological examination of the posterior segment was unremarkable.

Corneal neovascularization can lead to a devastating disease process that involves the breakdown of the limbal barrier and the formation of blood vessels in the cornea, leading to severe visual impairment. This review discusses the delicate balance between antiangiogenic and angiogenic factors that govern the antiangiogenic privilege of the cornea. Current treatment methods, clinical trials, and future prospects in the management of corneal neovascularization also are discussed.