Criteria for Preliminary Risk Assessment of Brownfield Site: An International Survey of Experts.

Comprehensive risk assessment of brownfield sites requires a broad range of knowledge and multi-disciplinary expertise. Whilst the identification of criteria requirements for preliminary risk assessment has received some attention, there appears to be no studies that have specifically examined professional perspectives relating to these requirements. Yet, variations in professional practitioners' assessments may have significant consequences for the assessment of risks, and how the criteria are imparted to stakeholders. This study aims to identify the criteria requirements for preliminary risk assessment, using the pollutant linkage model (Source-Pathway-Receptor), and explores cross-disciplinary professional perspectives related to these requirements. To this end, this study commenced with a systematic review to identify various criteria streams required for the preliminary risk assessment of brownfield sites. Thereafter, a questionnaire survey was design and shared with brownfield site professionals. Quantitative analysis of the survey responses (n = 76) reveals disciplines have markedly different priorities relating to the same hazard. For instance, geophysicists, geochemists, and hydrologists do not raise concerns regarding ground movement that can result from the removal of storage and tanks, whilst the same hazard was considered as having a high importance by other professions (such as geologists and geotechnical engineers). This example, amongst others revealed in the study, underpins potential issues and implications for various stakeholders compiling and/or using preliminary risk assessment criteria. This study clarifies both the key criteria requirements for the preliminary risk assessment of brownfield sites, as well as the importance of recognising how variation in professionals' perceptions plays in the risk assessment process. Although, specialist knowledge is essential for brownfield site investigation, so is the maintaining a broad-based view of other experts coming from different backgrounds, as this renders holistic risk assessment insights.

Behaviour and Microstructural Characteristics of Lime-GGBS-Treated Kaolin Clay Contaminated with Gypsum.

In this experimental study, the physico-mechanical and microstructural properties of sulphate-bearing clays have been investigated. Sulphate bearing soils constituted by mixing kaolin and gypsum at 0%, 15%, 25%, and 35% gypsum contents were treated with 12% ordinary Portland cement (OPC) and 4%Lime (L) and 8% ground granulated blast furnace slag (GGBS) and subjected to compaction, swell, unconfined compressive strength (UCS), California bearing ratio (CBR), and scanning electron microscopy (SEM) and energy dispersive spectrometry (EDX) analyses. The results of the study showed that the use of L-GGBS improved the soaked CBRs of the treated samples by over 43% when compared to OPC-treated samples after 7-days curing. A reduction in water absorption by 82% was also observed with L-GGBS treatment after 28-days curing. The UCS results also showed better performance with L-GGBS treatment exceeding 856% at 28 days. The effect of increased cementitious product with increasing gypsum content was negated by simultaneous and rapid growth of ettringite minerals which reduced the strength and increased swelling of OPC treated samples up to 18.92%, exceeding allowable limits of 2.5% as specified in Highway Agency Advice Note HA 74/07. The L-GGBS treated gypseous soil samples meet the strength requirement for stabilised sub-base (CS) and stabilised road-bases (CB1 and CB2) as described in TRL ORN31. Hence, the use of L-GGBS combination was found to be effective in ameliorating sulphate-induced expansion and therefore encouraged in the stabilisation of subgrade and road-base materials with high sulphate contents.

Wet-Dry Cycles and Microstructural Characteristics of Expansive Subgrade Treated with Sustainable Cementitious Waste Materials.

This work presents an experimental study on the physico-mechanical and microstructural characteristics of stabilised soils and the effect of wetting and drying cycles on their durability as road subgrade materials. The durability of expansive road subgrade with a high plasticity index treated with different ratios of ground granulated blast furnace slag (GGBS) and brick dust waste (BDW) was investigated. Treated and cured samples of the expansive subgrade were subjected to wetting-drying cycles, California bearing ratio (CBR) tests, and microstructural analysis. The results show a gradual reduction in the California bearing ratio (CBR), mass, and the resilient modulus of samples for all subgrade types as the number of cycles increases. The treated subgrades containing 23.5% GGBS recorded the highest CBR value of 230% under dry conditions while the lowest CBR value of 15% (wetting cycle) was recorded for the subgrade treated with 11.75% GGBS and 11.75% BDW at the end of the wetting-drying cycles, both of which find useful application in road pavement construction as calcium silicate hydrate (CSH) gel was formed in all stabilised subgrade materials. However, the increase in alumina and silica content upon the inclusion of BDW initiated the formation of more cementitious products due to the increased availability of Si and Al species as indicated by EDX analysis. This study concluded that subgrade materials treated with a combination of GGBS and BDW are durable, sustainable and suitable for use in road construction.

Strength Predictive Modelling of Soils Treated with Calcium-Based Additives Blended with Eco-Friendly Pozzolans-A Machine Learning Approach.

The unconfined compressive strength (UCS) of a stabilised soil is a major mechanical parameter in understanding and developing geomechanical models, and it can be estimated directly by either lab testing of retrieved core samples or remoulded samples. However, due to the effort, high cost and time associated with these methods, there is a need to develop a new technique for predicting UCS values in real time. An artificial intelligence paradigm of machine learning (ML) using the gradient boosting (GB) technique is applied in this study to model the unconfined compressive strength of soils stabilised by cementitious additive-enriched agro-based pozzolans. Both ML regression and multinomial classification of the UCS of the stabilised mix are investigated. Rigorous sensitivity-driven diagnostic testing is also performed to validate and provide an understanding of the intricacies of the decisions made by the algorithm. Results indicate that the well-tuned and optimised GB algorithm has a very high capacity to distinguish between positive and negative UCS categories ('firm', 'very stiff' and 'hard'). An overall accuracy of 0.920, weighted recall rates and precision scores of 0.920 and 0.938, respectively, were produced by the GB model. Multiclass prediction in this regard shows that only 12.5% of misclassified instances was achieved. When applied to a regression problem, a coefficient of determination of approximately 0.900 and a mean error of about 0.335 were obtained, thus lending further credence to the high performance of the GB algorithm used. Finally, among the eight input features utilised as independent variables, the additives seemed to exhibit the strongest influence on the ML predictive modelling.

Optimisation of Embodied Carbon and Compressive Strength in Low Carbon Concrete.

To improve the prediction of compressive strength and embodied carbon of low carbon concrete using a program algorithm developed in MATLAB, 84 datasets of concrete mix raw materials were used. The influence of water, silica fume and ground granular base slag was found to have a significant impact on the extent of low carbon concrete behaviour in terms of compressive strength and embodied carbon. While the concrete compressive strength for normal concrete increases with reducing water content, it is observed that the low carbon concrete using lightweight aggregate material increases in compressive strength with an increase in embodied carbon. From the result of the analysis, a function was developed that was able to predict the associated embodied carbon of a concrete mix for a given water-to-cement ratio. The use of an alkaline solution is observed to increase the compressive strength of low carbon concrete when used in combination with ground granular base slag and silica fume. It is further shown that ground granular base slag contributes significantly to an increase in the compressive strength of Low carbon concrete when compared with pulverised fly ash. The optimised mix design program resulted in a 26% reduction in embodied carbon and an R2 value of 0.9 between the measured compressive strength and the optimised compressive strength.

Road Pavement Thickness and Construction Depth Optimization Using Treated and Untreated Artificially-Synthesized Expansive Road Subgrade Materials with Varying Plasticity Index.

Road pavement thickness and their depth of construction take a chunk of the overall cost of road construction. This has called for a need for reduced road pavement thickness by improving the engineering properties of subgrade such as the California bearing ratio (CBR). The CBR of road subgrade has been a major determining factor for road pavement thickness, and expansive subgrades generally have a low CBR, resulting in major road defects. In this study, road pavement thickness and construction depth optimization were conducted using the CBR values achieved in this study. Additives proportions of 8% lime and 20% cement were used in expansive subgrade to improve their engineering properties, making them suitable for use in road construction. The study investigated the characteristics, mineral structure, Atterberg limit, compaction, CBR, swell and microstructural properties of expansive subgrade. The results show a reduction in road pavement thickness and a construction depth with an increase in CBR value. All CBR values for treated samples were above 2%, making them usable in road construction. A reduction in swell potential up to 0.04% was observed for treated expansive subgrade. The study concluded that pavement thickness and construction depth can be reduced by enhancing subgrade materials and using cement and lime as binders.

Analysis of the jugular foramen in pediatric patients with craniosynostosis.

INTRODUCTION: Intracranial hypertension due to craniosynostosis is a dreaded potential complication that affects the developing brain. We hypothesized that craniosynostotic patients have significantly reduced jugular foramen (JF) when compared with age-matched controls. This may partially account for the observed increase in intracranial pressure (ICP) seen in some of these patients. We also estimated the potential effects on ICP using the Hagen-Poiseuille equation. MATERIALS AND METHODS: Two institutional review board-approved groups were included in this study. Group 1 consists of 14 randomly selected craniosynostotic patients (7 boys and 7 girls; mean age, 9.33 mo; range, 0.6-21 mo). Group 2, the control group, consists of 27 children without craniosynostosis (13 boys and 14 girls; mean age, 8.71 mo; range, 0.23-45 mo). The same neuroradiologist used axial computed tomographic scans to measure the greatest anterior-posterior (AP) and lateral diameters of the jugular bulb. RESULTS: The right JF AP diameter is 23.02% smaller in group 1 than in group 2 (P = 0.0066, 2-tailed t-test). The left JF AP diameter was also smaller for group 1 but was not statistically significant (P = 0.257, 2-tailed t-test). Group 1 also had a nonsignificant increase in both lateral diameters (P > 0.05). DISCUSSION: The study showed a significant decrease (23.02%) in the right JF AP dimension in children with craniosynostosis. On the basis of the Hagen-Poiseuille equation, a 23.02% AP diameter reduction in 1 JF may theoretically increase the ICP 63.5% or 6.35 mm Hg, keeping all other variables, such as blood flow, constant. Although not supported by aspect ratio analysis, the slight increase in the lateral diameters of the patients' JFs may lessen this effect.

Aqueous gels of mixtures of ionic surfactant SDS with pluronic copolymers P123 or F127.

Gel diagrams based on tube inversion and oscillatory rheometry are reported for Pluronic copolymers F127 (E(98)P(67)E(98)) and P123 (E(21)P(67)E(21)) in mixtures with anionic surfactant sodium dodecyl sulfate (SDS). Total concentrations (c, SDS+copolymer) were as high as 50 wt % with mole ratios SDS/copolymer (mr) in the ranges 1-5 (F127) and 1-7 (P123). Temperatures were as high as 90 degrees C. Determination of the temperature dependences of the dynamic moduli served to confirm the gel boundaries from tube inversion and to reveal the high elastic moduli of the gels, e.g., compared at comparable positions in the gel phase, a 50 wt % SDS/P123 with mr = 7 had G' three times that of a corresponding gel of P123 alone. Small-angle X-ray scattering (SAXS) was used to show that the structures of all the SDS/F127 gels were bcc and that the structures of the SDS/P123 gels with mr = 1 were either fcc (c = 30 wt %) or hex (c = 40 wt %). Assignment of structures to SDS/P123 gels with values of mr in the range 3-7 was more difficult, as high-order scattering peaks could be very weak, and at the higher values of c and mr, the SAXS peaks included multiple reflections.

Medical waste management in Ibadan, Nigeria: obstacles and prospects.

Quantification and characterization of medical waste generated in healthcare facilities (HCFs) in a developing African nation has been conducted to provide insights into existing waste collection and disposal approaches, so as to provide sustainable avenues for institutional policy improvement. The study, in Ibadan city, Nigeria, entailed a representative classification of nearly 400 healthcare facilities, from 11 local government areas (LGA) of Ibadan, into tertiary, secondary, primary, and diagnostic HCFs, of which, 52 HCFs were strategically selected. Primary data sources included field measurements, waste sampling and analysis and a questionnaire, while secondary information sources included public and private records from hospitals and government ministries. Results indicate secondary HCFs generate the greatest amounts of medical waste (mean of 10,238 kg/day per facility) followed by tertiary, primary and diagnostic HCFs, respectively. Characterised waste revealed that only approximately 3% was deemed infectious and highlights opportunities for composting, reuse and recycling. Furthermore, the management practices in most facilities expose patients, staff, waste handlers and the populace to unnecessary health risks. This study proffers recommendations to include (i) a need for sustained cooperation among all key actors (government, hospitals and waste managers) in implementing a safe and reliable medical waste management strategy, not only in legislation and policy formation but also particularly in its monitoring and enforcement and (ii) an obligation for each HCF to ensure a safe and hygienic system of medical waste handling, segregation, collection, storage, transportation, treatment and disposal, with minimal risk to handlers, public health and the environment.

Magneto-biomonitoring of intra-urban spatial variations of particulate matter using tree leaves.

Preliminary mineral magnetic results from a pilot project investigating the suitability of roadside tree leaves as depositories of vehicular pollution are presented. Tree leaf surfaces (Lime: Tilia europaea; Sycamore: Acer pseudoplatanus) at four roadside and one woodland location in Wolverhampton, UK, have been monitored (July 2003 to November 2003). Mineral magnetic technologies have revealed spatial variations of particulate pollution concentration throughout the conurbation and data analysis indicates that magnetic concentration parameters are suitable proxies for fine particulate pollution, which are particularly hazardous to health. Site-specific traffic management and associated vehicle behaviour appear to be chiefly responsible for the magnetic concentration differences between sites. Magneto-biomonitoring in this way allows the high-resolution spatial mapping of particulate matter (PM) pollution, which may also benefit epidemiology in better assessing exposure to vehicular-derived particulates. Given the speed, measurement sensitivity and non-destructive nature of the technique, it is proposed that this low-cost approach offers some advantages over centralised monitoring stations to monitor urban roadside particulate pollution.

Solubilisation of drugs in worm-like micelles of block copolymers of ethylene oxide and 1,2-butylene oxide in aqueous solution.

Ethylene oxide and 1,2-butylene oxide were sequentially polymerised to form the diblock copolymer E13B10 (E=oxyethylene, B=oxybutylene, subscripts denote number-average block lengths in repeat units). Dynamic and static light scattering over the temperature range 10-30 degrees C demonstrated a transition from compact (spheroidal) micelles to larger, more elongated (worm-like) micelles with temperature increase above a critical onset temperature of about 20 degrees C. Determination of the solubilisation capacity for griseofulvin, carbamazepine and spironolactone of dilute micellar solutions of this copolymer, together with those of E11B8 and E17B12 block copolymers (which also show the sphere-to-worm transition), allowed investigation of the influence on solubilisation characteristics of hydrophobic block length and temperature. The extent of solubilisation at 25 degrees C of the poorly water-soluble drug spironolactone increased linearly with increase of hydrophobic block length, attributable to a concomitant increase in the proportion of worm-like micelles in solution.

Solubilisation of drugs in micellar solutions of diblock copolymers of ethylene oxide and styrene oxide.

The solubilisation of two poorly soluble drugs, furosemide and nabumetone, in micellar solutions of diblock copolymers of ethylene oxide and styrene oxide has been studied at 25 and 37 degrees C and solubilisation capacities compared with published values for griseofulvin and docetaxel. Solubilisation in the micelle core, corrected for the different proportions of poly(styrene oxide) in the copolymers, was similar for all four drugs. The highest solubilisation capacities were found for a copolymer with worm-like micelles.

Poly(ethylene oxide) based copolymers: solubilisation capacity and gelation.

It is thought that almost half of potentially useful drug candidates fail to progress to formulation development because of their low aqueous solubility and associated poor or erratic absorption characteristics. A response to this challenge has been the development of a variety of colloidal delivery systems in which the therapeutic agent is encapsulated in nanosized particles. In this review, attention is focussed on colloidal vectors based on amphiphilic block copolymers, the micelles of which can accommodate a wide range of water-insoluble guest molecules, and particularly on copolymers with poly(oxyethylene) as the hydrophilic block and with poly(oxyalkylene) or polyester hydrophobic blocks, taking advantage of the 'stealth' properties of the poly(oxyethylene) corona of their micelles. Although copolymers of this type have been commercially available for several decades in the form of the Pluronic (BASF) polyols, which have a poly(oxypropylene) hydrophobic block, they have not found wide application for drug solubilisation, primarily because of their low solubilisation capacity. In attempts to achieve greater drug loading, recent work has concentrated on copolymers in which the core-forming blocks are designed to be more hydrophobic and more compatible with the drug to be encapsulated. Progress in this area has been reviewed and recent developments in the design of block copolymers of this type that combine high drug loading capacity with thermally reversible gelation characteristics in the temperature range suitable for potential application as in situ gelling vehicles following subcutaneous injection have also been discussed.

Block copolymers for drug solubilisation: relative hydrophobicities of polyether and polyester micelle-core-forming blocks.

Published values of the critical micelle concentration are tabulated for diblock copolymers E(m)P(n), E(m)B(n), E(m)S(n), E(m)L(n), E(m)VL(n) and E(m)CL(n), where E denotes a chain unit derived from ethylene oxide, P from propylene oxide, B from 1,2-butylene oxide, S from styrene oxide, L from dl-lactide, VL from gamma-valerolactone and CL from epsilon-caprolactone, and the subscripts denote average chain lengths. Noting that log(cmc/moldm(-3) is proportional to the standard Gibbs energy of micellisation, the dependence of this quantity on hydrophobic block length (n) is explored for a given E-block length. Superposition of data allows ranking of the hydrophobicities of the chain units. The ratios relative to the least hydrophobic unit are: P : L : B : VL : S : CL = 1 : 4 : 6 : 10 : 12 : 12 Transitions in the slope of log(cmc) versus n are assigned to changes in the unimer-micelle equilibrium and related to the formation of unimolecular micelles and, at high values of n, to the completion of that process. The formation transition is seen in the plots for all the copolymers except the least hydrophobic, E(m)P(n). The completion transition is seen in the plots for E(m)CL(n) and E(m)L(n) copolymers, as these alone include results for copolymers with very lengthy hydrophobic blocks.

Mixtures of triblock copolymers E(62)P(39)E(62) and E(137)S(18)E(137) potential for drug delivery from in situ gelling micellar formulations.

The gelation behaviour of concentrated micellar solutions of mixtures of a block copolymer of ethylene oxide and styrene oxide (E(137)S(18)E(137)) with one of ethylene oxide and propylene oxide (E(62)P(39)E(62)) has been investigated. Over a wide range of compositions, up to 90 wt.% E(137)S(18)E(137) in the mixture, gelation resembled that of solutions of E(62)P(39)E(62) alone, i.e. they gelled on heating from ambient to body temperature. In related experiments, using the aromatic drug griseofulvin as a comparative standard, it was demonstrated that solubilisation efficiency of dilute micellar solutions of the mixtures with 80 wt.% or more E(137)S(18)E(137) approached that of solutions of E(137)S(18)E(137) alone. Thus it was shown that the mixed system could have both the satisfactory solubilisation capacity of micellar solutions of E(137)S(18)E(137) and the desirable gelation characteristics of E(62)P(39)E(62), and so have potential for use in drug release applications involving in situ gelation.

Triquetrohamate Impaction Syndrome: An Unrecognized Cause of Ulnar-Sided Wrist Pain; Its Presentation Further Defined.

BACKGROUND: The aim of this review was to further define the clinical condition triquetrohamate (TH) impaction syndrome (THIS), an entity underreported and missed often. Its presentation, physical findings, and treatment are presented. METHODS: Between 2009 and 2014, 18 patients were diagnosed with THIS. The age, sex, hand involved, activity responsible for symptoms, and defining characteristics were recorded. The physical findings, along with ancillary studies, were reviewed. Delay in diagnosis and misdiagnoses were assessed. Treatment, either conservative or surgical, is presented. Follow-up outcomes are presented. RESULTS: There were 15 male and 3 females, average age of 42 years. Two-handed sports such as golf and baseball accounted for more than 60% of the cases, and these cases were the only ones that involved the lead nondominant hand, pain predominantly at impact. Delay in diagnosis averaged greater than 7 months, with triangular fibrocartilage (TFCC) and extensor carpi ulnaris (ECU) accounting for more than 50% of misdiagnoses. Physical findings of note included pain over the TH joint, worse with passive dorsiflexion and ulnar deviation. Radiographic findings are described. Instillation of lidocaine with the wrist in radial deviation under fluoroscopic imaging with relief of pain helped to confirm the diagnosis. Conservative treatment was successful in 9 of 18 patients (50%), whereas in the remaining, surgical intervention allowed approximately 80% return to full activities without limitation. CONCLUSION: Triquetrohamate impaction syndrome remains an underreported and often unrecognized cause of ulnar-sided wrist pain. In this report, the largest series to date, its presentation, defining characteristics, and treatment options are further elucidated.

Controlling the gelation of aqueous micellar solutions of ethylene-oxide-based block copoly(oxyalkylene)s.

Micellar solutions of EmPnEm copolymers may be mobile at ambient temperature and form hard gels on warming to body temperature, whereas micellar solutions of EmSnEm copolymers do not show this effect (E denotes oxyethylene, P oxypropylene and S oxyphenylethylene, and subscripts m and n denote chain lengths). The aim of this study was to combine the desirable gelation characteristics of solutions of the EmPnEm copolymers with the greater solubilising capacities of solutions of the EmSnEm copolymers. Accordingly, the gelation characteristics in aqueous solution of binary mixtures of the triblock copolymer E62P39E62 (Pluronic F87) with E137S18E137, E82S9E82 or E76S5E76 were investigated by rheological techniques. We have shown that 50/50 wt.% mixtures of E62P39E62 with either E137S18E137 or E82S9E82 at a total copolymer concentration of approximately 30 wt.% are fluids of low viscosity at temperature below 22-25 degrees C and gels of high elastic modulus at body temperature.The mixed systems have potential as vehicles for the controlled delivery of solubilised drug from gels formed in situ following subcutaneous injection of a low viscosity aqueous solution.

Solubilisation in aqueous micellar solutions of block copoly(oxyalkylene)s.

The solubilisation capacities of micellar solutions of diblock and triblock copolymers composed of hydrophilic poly(ethylene oxide) and hydrophobic poly(styrene oxide) have been compared using the poorly water-soluble drug griseofulvin as a model solubilisate. Our results showed an increase of solubilisation capacity (expressed as mg griseofulvin per gram of hydrophobic block) with temperature and, for spherical micelles, with core volume before reaching limiting values. A change of micelle shape from spherical to cylindrical (or worm-like) resulting from an increase in micelle aggregation number was accompanied by a further enhancement of solubilisation capacity. Comparison with the solubilisation of the same drug in micellar solutions of block copolymers of poly(ethylene oxide) and poly(1,2-butylene oxide) showed that the solubilisation capacity of a poly(styrene oxide) block was approximately four times that of a poly(1,2-butylene oxide) block for spherical micelles. Solubilisation capacity at 25 degrees C was approximately doubled when griseofulvin was incorporated into a copolymer melt and micelles initially formed from the drug-loaded melt at 65 degrees C rather than by loading the drug into pre-micellised solution at 25 degrees C in the usual manner.

Association properties of diblock copolymer of ethylene oxide and 1,2-butylene oxide: E17B12 in aqueous solution.

Copolymer E(17)B(12) (E denotes OCH(2)CH(2), B denotes OCH(2)CH(C(2)H(5)), and the subscripts denote number-average chain lengths) was prepared by sequential oxyanionic polymerization and characterized by GPC (for distribution width) and NMR spectroscopy (for absolute composition and chain length). Dynamic and static light scattering and rheometry were used to characterize micelles in dilute solution and demonstrate the formation of compact micelles at low temperatures and of elongated micelles at higher temperatures, the latter being accompanied by turbidity of the solution. Rheological methods applied across a range of concentrations and temperatures served to demonstrate the formation of worm-like micelles. Gels based on entangled worm-like micelles (some of them turbid) and on packed compact micelles were identified and their properties were explored.

Micellization of block copolymer P94 in aqueous solution.

P94 is a triblock copolymer of poly(oxyethylene) and poly(oxypropylene), type EPE. Eluent gel permeation chromatography has been used to demonstrate the formation of large micelles in solutions of the copolymer at temperatures immediately above the critical micelle temperature. Values of the critical micelle temperature (cmt) obtained in this way are in excellent agreement with results from differential scanning calorimetry and surface tensiometry. A van't Hoff plot was used to define the concentration dependence of the cmt for dilute solutions (c < or =2 wt%) and to obtain an apparent value of the standard enthalpy of micellization. Using published data, comparison is made with the thermodynamics of micellization in concentrated solution (c > or =20 wt%).