CURRENT STATUS OF AMBEWELA RESERVOIR OF SRI LANKA WITH SPECIALREFERENCE TO WATER POLLUTION

The water pollution trends in the Ambewela reservoir at the uppermost catchment of Kotmale River was assessed through a study on chemical and bio monitoring programme that carried out from March to October 2008.The mean average value (mean ± SD) of the nitrate, nitrite, phosphate and ammonia concentrations in Ambewela reservoir were 0.780 ± 1.386 mg/l, 0.103 ± 0.223mg/l, 0.051 ± 0.061mg/l and 0.218± 0.261 mg/l whereas values for the streams selected from Dambagasthalawa Oya were 0.985 ± 0.902 mg/l, 0.099  ± 0.207mg/l, 0.038 ± 0.026 mg/l and 0.085± 0.077 mg/l respectively. Average Chlorophyll- a values of the reservoir were 17.85 ± 17.858 mg/m3 and 8.30 ± 4.686 mg/m3for other two streams accordingly. Average BOD values of the reservoir were 8.06 ± 3.494 and 4.25 ± 2.251 for other two streams correspondingly.The bio monitoring studies also clearly showed sudden records of huge colonies of  Hydra(approximately 258/cm3) in the reservoir from time to time. This phenomenon was found in relatively dry period that directly coincided with intensified use of agro chemicals. Moreover, steady population of Chironomid (average population density 208/cm3) that is commonly accepted pollution indicator was reported at Ambewela reservoir throughout the study period.Therefore, both chemical and bio monitoring studies indicate eutrophic condition in Ambewela reservoir in which long run might affect on the ecology of the entire ecosystem. Hence prompt mitigatory action should be implemented to avoid further depletion.Key Words: Ambewela Reservoir, Water Pollution, Physico-Chemical Parameters, Chlorophyll –

STUDY THE EFFECT OF SALINITY AND NUTRIENTS FOR THE GROWTH OF Najas marina AND ITS IMPACT TO AQUATIC BIODIVERSITY IN MADU GANGA RAMSAR WETLAND IN SRI LANKA

Madu Ganga is the latest addition to the Ramsar International Convention of Wetlands. Najas marinais an alien aquatic plant and 0.5 m long that are often branched toward the upward portion of the plant. The objective of the study was to study the impact of salinity and nutrients for the growth of Najas marina. Samples were collected for analysed water quality parameters from March, 2006 to January 2007 in the lagoon. Mapping was done using Garmin GPS map 76CS and Arc GIS used to developed maps.Mean nutrient such as, nitrate nitrogen, ammonia nitrogen and orthophosphate concentrations were observed 0.26 ± 0.3 mg/l, 0.057 ± 0.04 mg/l, and 0.354 ± 0.77 mg/l subsequently. Mean salinity variation in bottom and surface are 6.38 ± 6.65 ppt and 4.31 ±  4.68 ppt. Higher bottom salinity was observed in location number 02 (near to sea mouth) and  Najas marinawas not present in the area. Najas marina was also not recorded in upper part of the lagoon and fresh water streams studied. High density of Najas marina plants were observed in sampling location 07, 08 and 09, because of the high nutrient concentration flowing through feeding tributaries. More than 25 % of lagoon area was covered by Najas marina.

Human stomach microbiota: Effects on health and disease

The gut microbiota is a complex ecological community, consisting of trillions of microbes which include bacteria, viruses, fungi and protozoa. The stomach was previously considered as a sterile site uninhabited by microbes due to its hostile environmental conditions. Breaking this concept, Helicobacter pylori was the first pathogen reported to inhabit the stomach. Recent studies have suggested that the stomach harbours transient as well as certain commensal bacterial and fungal species. The five major microbial phyla in the stomach have been identified as Firmicutes, Bacteroidetes, Actinobacteria, Fusobacteria and Proteobacteria. The composition of gastric microbiota is dynamic and is affected by several factors.  These include age group, dietary habits, medication use, inflammation of gastric mucosa and H. pylori colonization.  Further, the role of host genetics has recently been studied in maintaining the stomach microbiota. Mutations in host genes may affect the host’s immune response towards commensal bacteria and reduce their number and diversity. The essential multiple roles of gut microorganisms include maintaining homeostasis in the gut, contributing to immune function and extraction of nutrients and energy from our diets.  Loss of the normal balance between the gut microbiota and host has been associated with several abnormal conditions and disorders such as obesity, malnutrition, inflammatory bowel diseases (IBD), neurological disorders, and cancer. In the stomach, the interaction between H. pylori and the gastric microbiota can also influence gastric dis­ease progression. Further studies should focus on addressing the role of gastric dysbiosis in health and disease. Identifying gastric microbiota is essential to understand how the gut microbiota and H. pylori affect health and disease.</p

Analysis of laser radiation using the Nonlinear Fourier transform

Modern high-power lasers exhibit a rich diversity of nonlinear dynamics, often featuring nontrivial co-existence of linear dispersive waves and coherent structures. While the classical Fourier method adequately describes extended dispersive waves, the analysis of time-localised and/or non-stationary signals call for more nuanced approaches. Yet, mathematical methods that can be used for simultaneous characterisation of localized and extended fields are not yet well developed. Here, we demonstrate how the Nonlinear Fourier transform (NFT) based on the Zakharov-Shabat spectral problem can be applied as a signal processing tool for representation and analysis of coherent structures embedded into dispersive radiation. We use full-field, real-time experimental measurements of mode-locked pulses to compute the nonlinear pulse spectra. For the classification of lasing regimes, we present the concept of eigenvalue probability distributions. We present two field normalisation approaches, and show the NFT can yield an effective model of the laser radiation under appropriate signal normalisation conditions

ULK1 inhibition overcomes compromised antigen presentation and restores antitumor immunity in LKB1-mutant lung cancer

Inactivating mutations in LKB1/STK11 are present in roughly 20% of nonsmall cell lung cancers (NSCLC) and portend poor response to anti-PD-1 immunotherapy. Unexpectedly, we found that LKB1 deficiency correlated with elevated tumor mutational burden (TMB) in NSCLCs from nonsmokers and genetically engineered mouse models, despite the frequent association between high-TMB and anti-PD-1 treatment efficacy. However, LKB1 deficiency also suppressed antigen processing and presentation, which are associated with compromised immunoproteasome activity and increased autophagic flux. Immunoproteasome activity and antigen presentation were restored by inhibiting autophagy through targeting the ATG1/ULK1 pathway. Accordingly, ULK1 inhibition synergized with PD-1 antibody blockade, provoking effector T-cell expansion and tumor regression in Lkb1-mutant tumor models. This study reveals an interplay between the immunoproteasome and autophagic catabolism in antigen processing and immune recognition, and proposes the therapeutic potential of dual ULK1 and PD-1 inhibition in LKB1-mutant NSCLC as a strategy to enhance antigen presentation and to promote antitumor immunity

Performance characterisation of AG/SAG mill pulp lifters using CFD techniques

The pulp lifter is an integral component of autogenous (AG) and semi-autogenous (SAG) grinding mills as it controls the throughput, performance and efficiency of mills. The slurry transport from the AG/SAG mill through grate holes into the discharge trunnion is the main function of the pulp lifter. This process develops complex flow behaviour in the region of the grate and pulp lifter. Efficient and effective removal of pulp/slurry from the mill is the key objective of the pulp lifter design. This work aims to understand slurry flow behaviour in pulp lifter sections and its contribution to mill performance using computational fluid dynamics (CFD) modelling and Laser Doppler Anemometry (LDA) measurements applied to a laboratory scale mill. The CFD model is validated against the LDA measurements, and then used to build a cohesive computational framework for modelling industrial pulp lifters, to investigate unique problems associated with their design and performance

Performance evaluation of the novel multi-shaft mill using DEM modelling

Comminution is well known to be an inefficient process and a large consumer of energy globally, giving rise to the development of novel comminution devices trying to exploit this opportunity. A multi-shaft mill, considered to be a novel comminution device, combines a series of rotating shafts with attached flingers which impact gravity fed material. The mill offers positive benefits in terms of plant footprint, high reduction ratio, high throughput and potential benefits through ore specific circuit integration. A process performance evaluation was conducted by surveying the mill along with using Discrete Element Method (DEM) modelling. The survey proved the mills ability to continuously sustain operation and product size for two different ore types under various configurations. The DEM predicted that gravity fed material entering the multi-shaft mill, with 50% of particles accelerated to a velocity higher than 184 km/h and 10% higher than 299 km/h. These velocities are converted to comminution energy through collisions with liners or particle-particle interactions. Each particle is subject to more than 24 impacts per second, greater than the critical breakage strength of a particle (0.01 kW h/t), leading to potential efficient comminution. Significant numbers of collisions were simulated in the mill alongside significant breakage being recorded through the surveying of the mill, leading to a reasonable comparison of product size distributions from the simulated adsorbed collision energies compared to the survey data. Using this baseline of the mills performance evaluation methodology further simulation work will aim to better quantify the breakage environment through a full-scale simulation run in parallel with future proposed survey work which will address wear rates and tailored operating conditions for specific ore types

Characterisation of superficial breakage using multi-size pilot mills

Low energy surface breakage has a high frequency of occurrence and thus plays a significant role in grinding processes. Yet this superficial breakage is poorly understood, measured and modelled - forming the focus of this work. Pilot mills of 0.8-1.8 m diameter, designed to provide a predominantly surface breakage environment with efficient removal of the resultant progeny, are utilised to characterise superficial breakage. A new rate, that of superficial breakage (1/(kW h/m2)), is introduced which measures fractional superficial breakage rate per energy provided to the surface of the material. This methodology is proposed as being suitable for understanding and characterising the surface breakage behaviour of ores. Tests were conducted on two ores with different hardness. Superficial breakage rates varied from 2 to 16 (1/(kW h/m2)) for the different ores and mill sizes, indicating a good sensitivity to ore type and the need to understand the applied stress - related to mill size. The results show that a single 'surface breakage rate for use in mill modelling is incorrect as the rate of superficial breakage is dependent on the size of the mill and therefore the inter-particle stressing conditions

Estimating energy in grinding using DEM modelling

The latest state of the art on Discrete Element Method (DEM) and the increased computational power are capable of incorporating and resolving complex physics in comminution devices such as tumbling mills. A full 3D simulation providing a comprehensive prediction of bulk particle dynamics in a grinding mill is now possible using the latest DEM software tools. This paper explores the breakage environment in mills using DEM techniques, and how these techniques may be expanded to provide more useful data for mill and comminution device modelling. A campaign of DEM simulations were performed by varying the mill size and charge particle size distribution to explore and understand the breakage environment in mills using DEM techniques. Analysis of each mill was conducted through consideration of the total energy dissipation and the nature of the collision environment that leads to comminution. The DEM simulations show that the mill charge particle size distribution has a strong influence on the mill input power and on the way the energy is distributed across the charge. The smaller particles experience higher energies while the larger experience less, but this variation is strongly dependent on the mill size. The results also showed that the average particle collision energy increases with increasing mill size, whereas its distribution over particle size is strongly influenced by the mill content particle size distribution. The simulations also captured the energy distribution within different regions of the tumbling charge, with the toe impact region having higher impact energies and the bulk shear region having higher tangential energies. Regardless of the mill size most of the energy is consumed by the particles in the mid-size range, which has the highest percentage mass of the total charge distribution