Geological Alterations and Chemical Treatment of a Polluted Limestone Foundation

A large factory for the production of concentrated sulphuric acid is constructed in 1977 and located in the west of Iraq near Al-Kaim city. The footings carrying the installations rest on calcareous rocks which extend deep into the ground. For many years, about 1.5 tons per day of acid seeped and percolated into the ground apart from frequent accidents when larger amounts took their path down into the ground. A record of the footings movement revealed that the footings experienced significant heave and settlement indicating a cyclic movement which depends on the frequency of seepage. The results of the past geotechnical and geochemical investigations have been carefully studied in order to trace the geological alterations occurring in the ground due to the percolation of sulphuric acid over years. It appeared that at certain depths the limestone rock has been almost converted to dough and that a significant amount of dolomitization has taken place in the factory ground. Contaminated samples have been obtained from boreholes executed in the factory site. Many chemical materials have been chosen to treat the contaminated samples. Among these materials are sodium silicate, sodium carbonate, sodium silicate plus calcium chloride, barium sulfate, aluminum oxide, ferric oxide and bentonite. Unconfined compression, ultrasonic wave, physical, wet chemical and XRD tests were performed on intact, contaminated and treated specimens. The results proved that sodium silicate is the best alternative to be used for chemical grouting of the ground. The use of calcium chloride with sodium silicate did not show an additional advantage. Samples contaminated to the degree of having the form of dough have almost regained their original solid state strength when treated with sodium silicate

Knowledge and Attitudes of Young People toward Mental Illness: A Cross Sectional Study

The aim of the study was to investigate young Jordanians’ knowledge and attitudes toward people who have a mental illness. A cross sectional design was utilized. A convenient sample of 858 participants aged between 15–24 years old completed a survey. Participants under 19 years were accessed through their schools and those 19 years and above were accessed through universities. Results showed that although the majority of university and school students’ responses were generally consistent, they disagreed on 11 items on the survey; for example, 186 (39.3%) of university students agreed that mental illness has a biological origin compared with only 119 (30%) of school students. The majority of young people 737 (85.9%) were willing to learn and 792 (92.3%) felt that they have to help people with mental illness, which make them willing to learn. In conclusion, the findings provide insights for decision makers and researchers in Jordan about young peoples’ knowledge and attitudes toward mental illness. Increasing young adults’ literacy through introducing educational programs such as mental health first aid courses will enrich their knowledge; help change attitudes and reduce stigma toward people living with mental illness

Accounting for Endogeneity in Maintenance Decisions and Overlay Thickness in a Pavement-Roughness Deterioration Model

Pavement deterioration models are an important part of any pavement management system. Many of these models suffer from endogeneity bias because of the inclusion of independent variables correlated with unobserved factors, which are captured by the model's error terms. Examples of such endogenous variables include pavement overlay thickness and maintenance and rehabilitation activities, both of which are not randomly chosen but are in fact decision variables selected by pavement engineers based on field conditions. Inclusion of these variables in a pavement deterioration model can result in biased and inconsistent model parameter estimates, leading to incorrect insights. Previous research has shown that continuous endogenous variables, such as pavement overlay thickness, can be corrected using auxiliary models to replace the endogenous variable with an instrumented variable that has lower correlation with the unobserved error term. Discrete endogenous variables, such as the type of maintenance and rehabilitation activities, have been accounted for by modeling the likelihood of each potential outcome and developing individual deterioration models for each of the potential responses. This paper proposes an alternative approach to accommodate discrete endogenous variables-the selectivity correction method-that allows a single model to incorporate the impacts of all discrete choices. This approach is applied to develop a pavement-roughness progression model that incorporates both continuous and discrete endogenous variables using field data from Washington State. The result is a roughness progression model with consistent parameter estimates, which have more realistic values than those obtained in previous studies that used the same data

The taper of cast post preparation measured using innovative image processing technique

<p>Abstract</p> <p>Background</p> <p>No documentation in the literature about taper of cast posts. This study was conducted to measure the degree of cast posts taper, and to evaluate its suitability based on the anatomy aspects of the common candidate teeth for post reconstruction.</p> <p>Methods</p> <p>Working casts for cast posts, prepared using Gates Glidden drills, were collected. Impressions of post spaces were made using polyvinyl siloxan putty/wash technique. Digital camera with a 10' high quality lens was used for capturing two digital images for each impression; one in the Facio-Lingual (FL) and the other in the Mesio-Distal (MD) directions. Automated image processing program was developed to measure the degree of canal taper. Data were analyzed using Statistical Package for Social Sciences software and One way Analysis of Variance.</p> <p>Results</p> <p>Eighty four dies for cast posts were collected: 16 for each maxillary anterior teeth subgroup, and 18 for each maxillary and mandibular premolar subgroup. Mean of total taper for all preparations was 10.7 degree. There were no statistical differences among the total taper of all groups (P = .256) or between the MD and FL taper for each subgroup. Mean FL taper for the maxillary first premolars was lower significantly (P = .003) than the maxillary FL taper of the second premolars. FL taper was higher than the MD taper in all teeth except the maxillary first premolars.</p> <p>Conclusions</p> <p>Taper produced did not reflect the differences among the anatomy of teeth. While this technique deemed satisfactory in the maxillary anterior teeth, the same could not be said for the maxillary first premolars. Careful attention to the root anatomy is mandatory.</p

A database of antimalarial drug resistance

A large investment is required to develop, license and deploy a new antimalarial drug. Too often, that investment has been rapidly devalued by the selection of parasite populations resistant to the drug action. To understand the mechanisms of selection, detailed information on the patterns of drug use in a variety of environments, and the geographic and temporal patterns of resistance is needed. Currently, there is no publically-accessible central database that contains information on the levels of resistance to antimalaria drugs. This paper outlines the resources that are available and the steps that might be taken to create a dynamic, open access database that would include current and historical data on clinical efficacy, in vitro responses and molecular markers related to drug resistance in Plasmodium falciparum and Plasmodium vivax. The goal is to include historical and current data on resistance to commonly used drugs, like chloroquine and sulfadoxine-pyrimethamine, and on the many combinations that are now being tested in different settings. The database will be accessible to all on the Web. The information in such a database will inform optimal utilization of current drugs and sustain the longest possible therapeutic life of newly introduced drugs and combinations. The database will protect the valuable investment represented by the development and deployment of novel therapies for malaria

Comparative analysis of co-processed starches prepared by three different methods

Co-processing is currently of interest in the generation of high-functionality excipients for tablet formulation. In the present study, comparative analysis of the powder and tableting properties of three co-processed starches prepared by three different methods was carried out. The co-processed excipients consisting of maize starch (90%), acacia gum (7.5%) and colloidal silicon dioxide (2.5%) were prepared by co-dispersion (SAS-CD), co-fusion (SAS-CF) and co-granulation (SAS-CG). Powder properties of each co-processed excipient were characterized by measuring particle size, flow indices, particle density, dilution potential and lubricant sensitivity ratio. Heckel and Walker models were used to evaluate the compaction behaviour of the three co-processed starches. Tablets were produced with paracetamol as the model drug by direct compression on an eccentric Tablet Press fitted with 12 mm flat-faced punches and compressed at 216 MPa. The tablets were stored at room temperature for 24 h prior to evaluation. The results revealed that co-granulated co-processed excipient (SAS-CG) gave relatively better properties in terms of flow, compressibility, dilution potential, deformation, disintegration, crushing strength and friability. This study has shown that the method of co-processing influences the powder and tableting properties of the co-processed excipient