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Objective: The purpose of this study was to examine the degree of contribution from the vertebrobasilar and carotid systems to the origin of the PCA in fetal autopsy brains of last trimester of pregnancy and to compare with published data on the configuration of adult and fetal brains in a population of Sri Lankan origin. Materials and Methods: The external diameter of the PcomA, pre-communicating part (P1), and the post-communicating part (P2) of posterior cerebral artery (PCA) of 34 fetal brain in the last trimester of pregnancy (30 to 40 weeks of gestation) was measured using a stereomicroscope equipped with a micrometer calibrator. Results : The blood supply to the occipital lobe mainly via the PCA was seen in 25 (59%) of fetal brains as compared to that in the literature 220 (93%) in adults brains and the blood supply to the occipital lobe mainly via the internal carotid artery (ICA) was seen in 16 (34%) of fetal brains as compared to 25 (7%) of adults brains (P < 0.0001), transitional configuration where the PcomA is equal in diameter to P1 segment of the PCA was seen in 5 (7.4%) of fetal brains and 8 (2%) of adults brains. Conclusions: The present study reveals that from the newborn to the adult there is shift from carotid system to the vertebrobasilar system, this justifies further studies on different racial and geographic regions which may give a clearer picture about the cerebral hemodynamics from childhood to adult.

This paper presents the results of a study conducted to ascertain the extent to which participants studying in an open and distance learning context utilized the mediation tools provided in an "Advanced Writing Skills" course, conducted in a blended-learning mode in Sri Lanka. Sixty-four participants engaged in the online component of the writing course using the Process Approach. The course consisted of seven sessions; four addressing the stages of the Process Approach to writing an essay, and three practice sessions. Data were gathered from log-files of the Learning Management System, questionnaires, and interviews related to five mediation tools provided to learners. The data were analyzed utilizing Engeström's activity theory framework (1987); with focus on the contradictions that emerged in the use of each tool. First, the contradictions that emerged in participants' engagement with the tools is presented, secondly, the factors that need to be taken into account to ensure greater engagement.

Abstract Background The variations of the circle of Willis (CW) are clinically important as patients with effective collateral circulations have a lower risk of transient ischemic attack and stroke than those with ineffective collaterals. The aim of the present cadaveric study was to investigate the anatomical variations of the CW and to compare the frequency of prevalence of the different variations with previous autopsy studies as variations in the anatomy of the CW as a whole have not been studied in the Indian subcontinent. Methods The external diameter of all the arteries forming the CW in 225 normal Sri Lankan adult cadaver brains was measured using a calibrated grid to determine the prevalence in the variation in CW. Chisquared tests and a correspondence analysis were performed to compare the relative frequencies of prevalence of anatomical variations in the CW across 6 studies of diverse ethnic populations. Results We report 15 types of variations of CW out of 22 types previously described and one additional type: hypoplastic precommunicating part of the anterior cerebral arteries (A1) and contralateral posterior communicating arteries (PcoA) 5(2%). Statistically significant differences (p < 0.0001) were found between most of the studies except for the Moroccan study. An especially notable difference was observed in the following 4 configurations: 1) hypoplastic precommunicating part of the posterior cerebral arteries (P1), and contralateral A1, 2) hypoplastic PcoA and contralateral P1, 3) hypoplastic PcoA, anterior communicating artery (AcoA) and contralateral P1, 4) bilateral hypoplastic P1s and AcoA in a Caucasian dominant study by Fisher versus the rest of the studies. Conclusion The present study reveals that there are significant variations in the CW among intra and inter ethnic groups (Caucasian, African and Asian: Iran and Sri Lanka dominant populations), and warrants further studies keeping the methods of measurements, data assessment, and the definitions of hypoplasia the same.

Background: In this study, we designed a novel genetic circuit sensitive to Cd2+, Zn2+ and Pb2+ by mimicking the CadA/CadR operon system mediated heavy metal homeostasis mechanism of Pseudomonas aeruginosa. The regular DNA motifs on natural operon were reconfigured and coupled with the enhanced Green Fluorescent Protein (eGFP) reporter to develop a novel basic NOT type logic gate CadA/CadR-eGFP to respond metal ions mentioned above. A Genetically Engineered Microbial (GEM)-based biosensor (E.coli-BL21:pJET1.2-CadA/CadR-eGFP) was developed by cloning the chemically synthesised CadA/CadR-eGFP gene circuit into pJET1.2-plasmid and transforming into Escherichia coli (E. coli)-BL21 bacterial cells. Results: The GEM-based biosensor cells indicated the reporter gene expression in the presence of Cd2+, Zn2+ and Pb2+ either singly or in combination. Further, the same biosensor cells calibrated for fluorescent intensity against heavy metal concentration generated linear graphs for Cd2+, Zn2+ and Pb2+ with the R2 values of 0.9809, 0.9761 and 0.9758, respectively as compared to non-specific metals, Fe3+ (0.0373), AsO43− (0.3825) and Ni2+ (0.8498) making our biosensor suitable for the detection of low concentration of the former metal ions in the range of 1–6 ppb. Furthermore, the GEM based biosensor cells were growing naturally within the concentration range of heavy metals, at 37 °C and optimum pH = 7.0 in the medium, resembling the characteristics of wildtype E.coli. Conclusion: Finally, the novel GEM based biosensor cells developed in this study can be applied for detection of targeted heavy metals in low concentration ranges (1–6 ppb) at normal bacterial physiological conditions. [ABSTRACT FROM AUTHOR]

Elephant-train collisions are a serious problem as a result of the ongoing human-elephant conflict in Sri Lanka. Lack of enough response time as a result of things like poor driver sight at sharp corners, midnight train operations, and severe weather conditions is one of the main causes of these incidents. The majority of these mishaps routinely take place at predetermined spots along known elephant trails and corridors. We suggest creating a unique system using Convolutional Neural Networks (CNNs) for precise elephant recognition and the construction of an early warning system in response to this urgent situation. By utilizing powerful computer vision techniques, this system attempts to improve railway safety in conflict-prone locations. The suggested system will continually monitor its surroundings by installing strategically placed cameras along train tracks. The system will be trained to successfully recognize elephants in realtime video streams using CNNs. When elephants are detected near the tracks, the device activates an early warning mechanism, notifying train operators and allowing them to take preventive actions. By offering a novel way to reduce train-elephant accidents, this study tackles a crucial facet of human-elephant conflict. Modern technology and real-time monitoring combined with the suggested method have the ability to drastically minimize accidents and ensure the safety of both human populations and elephant herds. The adoption of focused mitigation methods may also be facilitated by the capacity to recognize collision prone regions. Through this project, we help to promote peaceful cohabitation between people and elephants while protecting these amazing animals for future generations. [ABSTRACT FROM AUTHOR]