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This paper provides a thorough investigation of the effect of a top low-permeability (TLK) layer on transient saltwater intrusion dynamics prompted by water table fluctuations and sea level rise. Laboratory experiments were conducted on a 2D-sandbox and numerical simulations were performed using the SEAWAT code. Four cases were investigated, including a homogeneous case and three cases, where the top layer thickness (Wtop) was equal to 0.2H, 0.33H and 0.5H, respectively, where H was the aquifer thickness. The experimental and numerical results show that the toe length decreases linearly with increasing the thickness of the TLK layer. The results also suggest that lowering the permeability of the upper part of the aquifer causes faster saltwater removal process. The sensitivity analysis shows that decreasing the top layer permeability causes further reduction of the intrusion length. Nonetheless, the results evidence that this method yields relatively little reduction of the saline water intrusion length if the upper layer thickness is inferior or equal to a fifth of the total aquifer thickness, regardless of the permeability value of the top layer. The field-scale modelling results demonstrate that the performance of the TLK layer weakens noticeably as the hydraulic gradient decreases. The results show that the TLK layer achieved a maximum saltwater wedge reduction of 31% in the case where Wtop = 0.75H, which means that lowering the permeability of three fourths of the aquifer thickness only induced a toe length reduction by nearly a third of its original length. In addition to providing a quantitative analysis of SWI dynamics in bi-layered coastal aquifers, this study questions the performance and practicality of the artificial reduction of the upper aquifer permeability as a countermeasure for seawater intrusion control.

Background: Vitamin D has an immuomodulatory role in vaccine response and this may be mediated via its action on antigen presenting cells with the most potent effects on dendritic cells. Aim of work: was to determine if there is an association between circulating 25(OH)D concentrations and BCG vaccine cytokine response (interferon gamma) level. Methods: A cross sectional study included 80 infants aged 4 - 9 months from the pediatric outpatient clinic of Al-Zahraa university hospital (40 with normal weight and 40 with underweight). Participants were subjected to history taking, clinical examination, and laboratory investigations, particularly 25 hydroxy vitamin D [25(OH)D] and BCG vaccine-induced interferon gamma (IFN-γ). Results: The study showed that the underweight group had a lower socioeconomic level and higher percentage of breastfeeding compared with the normal weight group. Most infants in our study received vitamin D supplementation (80% and 62.5% in normal and underweight groups, respectively). The average serum level of 25(OH)D was relatively high (>100 ng/ml) in both normal and underweight groups. The mean levels of IFN-γ in response to BCG vaccine were not significantly different between the normal and underweight groups of infants in our study. Also, there was a statistically-significant moderate correlation between serum levels of 25(OH)D and BCG vaccine-induced IFN-γ in both normal (r = 0.58) and underweight (r = 0.64) groups. Conclusion: A good vitamin D status was observed in all studied infants irrespective of their nutritional status and significant correlation with BCG vaccine induced IFN-γ.

High concentration of fluoride ion up to 12 mg/l is observed in deep groundwater at the Tono area, Ja pan. A simple but general method to evaluate the occurrence of high fluoride ion concentration in groundwater has reported in this study. Our method based on the water-rock interaction test using different sizes of granite powders sampled from a boring core drilled at the site. Results indicated that, the weathering of granitic rock might be one of the key components for changing the fluoride ion concentrations. And also the increase of the reaction time led to enhance leaching of the fluoride ion from granite. To deduce the contribution of the co-existence of the chemical parameters, which affected on the change in the fluoride ion concentration, a stochastic model was developed. This model shows significant evaluation of the water-rock interaction test with the chemical data of a low Na-(Ca)-Cl water-type. Results from our stochastic model indicated that the approximation reaction time of the water-rock in the granitic groundwater was about 300 days at this region.