http://dr.lib.sjp.ac.lk/handle/123456789/10366 2026-01-07T05:58:47Z 2026-01-07T05:58:47Z Ratnarajah, V.R. Gnanachelvam, N.G. http://dr.lib.sjp.ac.lk/handle/123456789/10389 2022-03-03T09:09:40Z 2021-05-31T00:00:00Z

Effect of Abiotic Stress on Onion Yield: A Review Ratnarajah, V.R.; Gnanachelvam, N.G. Onion (Allium cepa L.) is a spice crop and a valuable economic crop cultivated in a variety of environments around the world. Because of its export demand, it is extremely important in terms of foreign exchange. Drought stress, waterlogging stress, heat stress, cold stress, and salinity stress all have an impact on onion growth, production, and yield in different ways. A lack of water causes low productivity, therefore to increase onion yield, a constant supply of water is needed. Onions are particularly susceptible to salt stress. The number of bulbs per unit area, height, and fresh weight of onion bulbs, are all affected by salinity in irrigation water. It has an effect on bulbing and the quality of harvested bulbs. Waterlogging has a major effect on bulb development and yield at various growth stages. Waterlogging stress in onions may prevent moving from source to sink, lowering bulb yield. The possible flavor of onions can be affected by the surrounding climate. The bulbing response is influenced by temperature, and the degree to which it is influenced varies by variety. As the temperature increases, the number of leaves decreases. The bulb diameter, bulb weight, and bulbing index (bulb/neck diameter) all increase as the temperature rises. This review provides an in-depth description of the effect of abiotic stress on onion yield.

2021-05-31T00:00:00Z Jayetileke, H.R. de Mel, W.R. Ratnayake, H.U.W. http://dr.lib.sjp.ac.lk/handle/123456789/10388 2022-03-02T10:26:41Z 2021-05-31T00:00:00Z

Dynamic Optimization Self-adaptive AI Controller for a Four-wheel Independent Drive Electric Rover Jayetileke, H.R.; de Mel, W.R.; Ratnayake, H.U.W. In this paper, a dynamic optimization self-adaptive controller for a four-wheel independent drive electric rover has been investigated to enhance the dynamic stability. The proposed self-adaptive AI controller is based on dynamic Fuzzy Logic (FL) control mechanism. The dynamic self-adaptive properties have been integrated into the proposed FL controller through a dynamically tuned Particle Swarm Optimization (PSO) mechanism. Nevertheless, the dynamic FL controller and the dynamic PSO mechanism has been synchronized together for every sampling instance k to obtain the optimum performance of the electric rover. In this electric rover, all the four wheels have a fixed orientation and each wheel powered by a 250-Watt Brushless Direct Current (BLDC) motor through separate gear ratio mechanisms to obtain the desired torque and angular velocity. Therefore, the steering mechanism was achieved in this rover through the proposed AI controller, which was based on the differential speed mechanism. However, this paper presents the control methodology and obtained test results related to straight road tests under different slippery road conditions. The rover test results show that on different slippery road conditions the proposed PSO based FL controller has maintained the wheel slip ratio of all the four wheels which was less than 0.35 approximately. Here, the translational speed has been limited to 40 km/hr approximately within its recorded top speed of 90 km/hr while maintaining the desired fix orientation.

2021-05-31T00:00:00Z Vivehananthan, K. Luphzhy, M.P.D.L. http://dr.lib.sjp.ac.lk/handle/123456789/10387 2022-03-02T10:17:00Z 2021-05-31T00:00:00Z

Detection of mecA Gene and Identification of Potential Methicillin-resistant Staphylococcus Aureus in Hospital Wastewater Samples Vivehananthan, K.; Luphzhy, M.P.D.L. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important causes of hospital infections worldwide. Methicillin-resistant S. aureus (MRSA) tends to be resistant to multiple antibiotics. High-level resistance to antibiotics is caused by the mecA gene, which encodes an alternative penicillin-binding protein, PBP 2a. The present study was aimed to detect mecA gene in potential methicillin-resistant Staphylococcus aureus (MRSA) isolates in clinical wastewater. Three hospital wastewater samples were collected, and the bacteria were isolated in mannitol salt agar (MSA) medium and Baird-parker agar medium. Gram staining and biochemical tests were performed. PCR amplification of extracted DNA from these bacterial isolates was done with 16S rRNA universal primers, specific primers of S. aureus and mecA gene primers to screen the clinical bacterial isolates. Sequencing of mecA gene amplicon was also done. The sequences were analyzed using BLAST (NCBI) and EMBOSS Needle tool (EMBL-EBI). Moreover, antibiotic resistance was tested at the levels of 50, 100, 200 and 300 μg/mL ampicillin. PCR amplification with all the primers screened was resulted expected bands for the isolates from Polgahawela and Chilaw wastewater. Two bacterial isolates of Polgahawela hospital effluent were able to grow at 200 μg/mL ampicillin. However, sequence analysis of amplified mecA gene product of these two bacterial isolates showed sequence similarity with the penicillin-binding protein (mecA) gene of Staphylococcus aureus strain and methicillin-resistance gene region of Staphylococcus sciuri 28C with 95% and 96% identity, respectively. Pairwise alignment results proved 89.6% sequence similarity between the two sequences. In conclusion, potential methicillin-resistant staphylococcus aureus (MRSA) along with Staphylococcus sciuri was able to detect only in the clinical effluent collected from Polgahawela base hospital.

2021-05-31T00:00:00Z Branavan, U. Wijesundera, S. Chandrasekharan, V. http://dr.lib.sjp.ac.lk/handle/123456789/10386 2022-03-02T10:08:20Z 2021-05-31T00:00:00Z

Potential Genetic Polymorphisms Predicting Polycystic Ovary Syndrome (PCOS) in Sri Lankan Women: Comparison with Different Ethnicity Branavan, U.; Wijesundera, S.; Chandrasekharan, V. Polycystic ovary syndrome (PCOS) is the commonest endocrine disorder of young women with long-term metabolic risk and prevalence among pre-marital Sri Lankan women is 6.3%. Inheritance of PCOS is likely to be oilgogenic; the genetic basis remaining largely unknown in view of the complex pathophysiology. The genetics of expression of PCOS requires an in-depth study, particularly among Sri Lankan women who have a greater metabolic risk from an early age. The emergence of an unanimously accepted genetic marker for susceptible PCOS was affected based on inconsistent findings. In this review, we summarize the common genetic polymorphisms of PCOS from different countries and outline some genetic polymorphisms that are potentially associated with the risk of PCOS in Sri Lankan women. This information could uncover candidate genes associating with PCOS, which will be valuable for the development of novel diagnostic and treatment method.

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