Evaluation of cover materials for a large scale test facility at Key Lake

Engineered soil cover systems have gained popularity in recent years as a preferred method of decommissioning and reclaiming waste management facilities. The main functions of a soil cover system are to minimize water infiltration, limit gas migration, resist weathering and erosion, and provide support for vegetation. In 1992, Cameco Corporation constructed a large scale non-vegetated prototype soil cover at Key Lake in north-central Saskatchewan. Their main objective was to evaluate the suitability of using local tills and sands for cover materials during future decommissioning of various waste management facilities at the site. An instrumentation and monitoring program was initiated in 1993 to verify the field performance of the soil cover system. The prototype soil cover was constructed over leached cobble ore that was enclosed within a double lined containment system. The soil cover consisted of a 60 cm layer of outwash glacial sand overlain by a 60 cm layer of compacted till. The test facility is essentially a large scale lysimeter whereby net infiltration is determined by monitoring the change in water table depth, the quantity of water removed from the facility, and the soil moisture profile. The instrumentation and monitoring program included a weather station, thermal conductivity sensors and neutron probe access holes, a Bowen Ratio Instrumentation, and a runoff collection and monitoring system. A laboratory program was undertaken to define pertinent soil parameters such as the soil-water characteristic curve and hydraulic conductivity. Laboratory calibration of the neutron probe was also carried out. A field soil testing program was completed to determine in situ density and hydraulic conductivity. The weather monitoring program yielded reliable precipitation, air temperature, and wind speed data. Instrumentation error was noted for relative humidity, net radiation, and pan evaporation parameters. The surface runoff monitoring system provided reliable runoff data on a real time basis. The thermal conductivity sensors were found to underestimate the soil moisture content, while the neutron probe was found to overestimate. The laboratory testing indicated that the outwash sand and the compacted till possessed similar soil water characteristic curves. The similarities in their water storage and release characteristics preclude the ability of these soils to form an effective capillary barrier when the till is overlain by the outwash sand. The field investigation has revealed that the soil cover system was underlain by a layer of extraneous sand and till material, most likely used to grade the facility prior to constructing the soil cover. The field performance of an engineered soil cover system is determined by the net infiltration through the system. The net infiltration for the 1996-1997 monitoring year was estimated to be 52% (287 mm) of the total annual precipitation(555 mm of precipitation from October 1996 to April 1997, inclusively). There was an insignificant change in the subsurface soil moisture storage. The surface runoff was recorded to be 6% (35 mm) of the total annual precipitation. The actual evaporation was estimated to be 30% (167 mm). The evaluation of the soil cover design has suggested that the Key Lake outwash sand overlain by the Key Lake till will not form a capillary barrier. Furthermore, the thickness of the till layer far exceeded the evaporative zone depth of the material, and therefore, infiltrated water could not have been extracted through evaporation even if the two soils had formed a capillary barrier. The net water storage capacity of the cover system was found to be inadequate (12 mm) to store larger rainfall events, thus further contributing to net infiltration. Incorporating surface vegetation has the potential to increase the total storage capacity to 42 mm; vegetation will also increase total evapotranspiration. A detailed analysis of the surface runoff and infiltration characteristics has indicated that runoff was governed by rainfall intensity and antecedent soil moisture conditions. Surface runoff was generated regardless of soil moisture conditions when the 15-minute rainfall intensity exceeded 1.4 mm. This intensity corresponds to a surface hydraulic conductivity (till) of 1.5 x 10-6 m/s; the laboratory determined hydraulic conductivity was 2.0 x 10-7 m/s

Combination Drug Delivery Approaches in Metastatic Breast Cancer

Disseminated metastatic breast cancer needs aggressive treatment due to its reduced response to anticancer treatment and hence low survival and quality of life. Although in theory a combination drug therapy has advantages over single-agent therapy, no appreciable survival enhancement is generally reported whereas increased toxicity is frequently seen in combination treatment especially in chemotherapy. Currently used combination treatments in metastatic breast cancer will be discussed with their challenges leading to the introduction of novel combination anticancer drug delivery systems that aim to overcome these challenges. Widely studied drug delivery systems such as liposomes, dendrimers, polymeric nanoparticles, and water-soluble polymers can concurrently carry multiple anticancer drugs in one platform. These carriers can provide improved target specificity achieved by passive and/or active targeting mechanisms

Effects of depressive symptoms and family satisfaction on health related quality of life: The Hong Kong FAMILY study

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Depressive symptoms in people with chronic physical conditions: Prevalence and risk factors in a Hong Kong community sample

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Effects of Dietary Katuk Leaf Extract on Growth Performance, Feeding Behavior and Water Quality of Grouper Epinephelus Coioides

- Plant-derived materials are believed as potential nutrient sources to be applied in aquaculture. Although many studies to assess the benefits of plant extracts have been conducted, however effects of dietary katuk (Sauropus androgynus L. Merr.) on growth performances, feeding behavior and water quality of grouper (Epinephelus coioides) are not well known. In this study, 25 grouper juveniles weighing 11.27 ± 2.53 g were reared into 100-L tank (60 x 50 x 35 cm) and cultivated for 70 days. The fish were divided into four groups in triplicate, and were offered diet without katuk extract (control), diet supplemented with 1% katuk extract (SAA); diet supplemented with 2.5% katuk extract (SAB) and diet supplemented with 5.0% katuk extract (SAC) twice daily. Statistical analyses showed that dietary katuk extract caused a significant (P < 0.05) increase in growth rate and feed intake. The efficiency of feed was also significant when fish offered diets supplemented with 1% of katuk extract which indicated by a lower feed conversion ratio. However, no statistical differences were observed on the survival rate, condition factor, viscerosomatic index and hepatosomatic index. Observation on feeding behavior found that all treated fish consumed compounded diet just after provided into their tank and there were no abnormal behavior or any healthy problems during experimental periods. It demonstrated that application of katuk extract in fish diets is acceptable and can stimulate the fish appetites. In conclusion, our studies indicated that dietary katuk (Sauropus androgynus) extract can be applied in aquaculture to stimulate the growth and improve feed utilization

Allele-Specific Chromatin Immunoprecipitation Studies Show Genetic Influence on Chromatin State in Human Genome

Several recent studies have shown a genetic influence on gene expression variation, including variation between the two chromosomes within an individual and variation between individuals at the population level. We hypothesized that genetic inheritance may also affect variation in chromatin states. To test this hypothesis, we analyzed chromatin states in 12 lymphoblastoid cells derived from two Centre d'Etude du Polymorphisme Humain families using an allele-specific chromatin immunoprecipitation (ChIP-on-chip) assay with Affymetrix 10K SNP chip. We performed the allele-specific ChIP-on-chip assays for the 12 lymphoblastoid cells using antibodies targeting at RNA polymerase II and five post-translation modified forms of the histone H3 protein. The use of multiple cell lines from the Centre d'Etude du Polymorphisme Humain families allowed us to evaluate variation of chromatin states across pedigrees. These studies demonstrated that chromatin state clustered by family. Our results support the idea that genetic inheritance can determine the epigenetic state of the chromatin as shown previously in model organisms. To our knowledge, this is the first demonstration in humans that genetics may be an important factor that influences global chromatin state mediated by histone modification, the hallmark of the epigenetic phenomena

Psychometric evaluation of the Chinese version of the subjective happiness scale: Evidence from the Hong Kong FAMILY cohort

BACKGROUND: With China's rapid economic growth in the past few decades, there is currently an emerging focus on happiness. Cross-cultural validity studies have indicated that the four-item Subjective Happiness Scale (SHS) has high internal consistency and stable reliability. However, the psychometric characteristics of the SHS in broader Chinese community samples are unknown. PURPOSE: We evaluated the factor structure and psychometric properties of the SHS in the Hong Kong general population. METHODS: The Chinese SHS was derived using forward-backward translation. Of the Cantonese-speaking participants aged >/=15 years, 2,635 were randomly selected from the random sample component of the FAMILY Cohort, a territory-wide cohort study in Hong Kong. In addition to the SHS, a single-item overall happiness scale, the Patient Health Questionnaire-9 (PHQ-9), the Family Adaptation, Partnership, Growth, Affection, Resolve (APGAR) scale, and the Medical Outcomes Study 12-item short-form version 2 (SF-12) mental and physical health scales were administered. RESULTS: Exploratory and confirmatory factor analyses supported a single factor with high loadings for the four SHS items. Multiple group analyses indicated factor invariance across sex and age groups. Cronbach's alpha was 0.82, and 2-week test-retest reliability (n = 191) was 0.70. The SHS correlated significantly with single-item overall happiness (Spearman's rho [rho] = 0.57), Family APGAR (rho = 0.26), PHQ-9 (rho = -0.34), and mental health-related quality of life (rho = 0.40) but showed a lower correlation with physical health (rho = 0.15). A regression model that included the PHQ-9 and Family APGAR scores explained 37 % of the variance in SF-12 mental health scores; adding the SHS raised the variance explained to 41 %. CONCLUSIONS: Our results support the reliability and validity of the SHS as a relevant component in the measurement battery for mental well-being in a Chinese general population.published_or_final_versio