Ethical conduct of research involving humans has gained relevance and importance over the years with the expansion of research beyond boundaries of traditional medical and clinical research into a multiplicity of disciplines with human participation. Human research is regarded as research conducted on or with or about people, or their tissues or cells or data obtained from them. Historically, it is stated that the Greek Philosopher Aristotle (384-322 BCE) was probably the first to discuss principles of ethics ‘by studying and offering criteria to assess human behaviour’. It is believed that he taught a course of ethics at the Lyceum during his mature years which was based on the many treatises he wrote on the subject. Increased attention to ethics in human research started after the Second World War following the judgment of the International Military Tribunal which also included 10 principles of permissible medical experiments which have since then been referred to as the Nuremburg Code (1949). Later discussions by the World Medical Assembly of the Code led to the adoption of the Helsinki Declaration (1964) which has been revised many times since then. The Council for International Organizations of Medical Sciences (CIOMS) which in association with the World Health Organizations (WHO) undertook its work on ethics in biomedical research in late 1970s. It has published an updated version with a wider scope of coverage titled ‘International Ethical Guidelines for Health-Related Research Involving Humans’ (2016). Close cooperation with World Medical Assembly has ensured that the guidelines are closely aligned to the Helsinki Declaration.  Traditionally, ethics has received much attention both in clinical practice and in health research. Faculties of Medicine were the first to establish ethics review boards and ethics review committees in Sri Lanka to undertake review of research proposals with human participation for ethical aspects and issues and granting approval. The primary aim is to safeguard the interests and right of participants of research and prevent their exploitation. There is no doubt about the value of health research and the benefits it has brought and will continue to bring to ensure health, wellbeing, safety and quality of life of people. Most research on human participants is simple, observational, descriptive and non-invasive and the ethical issues though may be minimal, still needs explicit attention and review by an ethics review board before approval. The more complex research where human participants are subject to ‘experimentation’ or ‘interventions’ has many ethical issues that need to assessed by recognized ethics review committees with experience and capability to do so.  If a new drug, a new vaccine, medicinal product, device, or equipment not already in use by people is to be tested on humans before being granted approval for use in day-to-day life by the appropriate authority, the researcher should adopt recommended procedures, regulations and registration mechanism prescribed. In Sri Lanka any interventional research requires applying and obtaining approval of ethics review committees that have been gazetted under the National Medicines Regulatory Authority (NMRA) as being approved by name to undertake ethics review. The interventional research should also be registered with the Sri Lanka Clinical Trials Registry. Both these need to be submitted to the Clinical Trials Evaluation Committee of the NMRA in order to be evaluated prior to being granted approval and registration. These approvals and registrations are also requested by peer reviewed high impact journals to consider such research manuscripts for publication.  There are certain values which provides the framework for principles guiding formulation of research proposals and ethics of research. These include and are not limited to respect, integrity, justice, beneficence and research merit. It is implicit in research that badly designed, conduced, analysed and reported research is unethical.  Clinical Centre researchers at National Institute of Health of USA have enunciated seven principles to guide the conduct of ethical research. These are social and clinical value, scientific validity, fair subject selection, favourable risk benefit ratio, independent review, informed consent, respect for potential and enrolled subjects. Given the importance of scientific merit and integrity of research, good research practice needs much attention both by researchers and research institutions.  In order to meet these needs the National Health Research Council and the Education, Training and Research Unit of the Ministry of Health have taken steps to publish, ‘The Code of Conduct on Health Research in Sri Lanka’ (2018) (available at http://www.health.gov.lk/moh_final/english/public/elfinder/files/publications/2018/TheCodeofConduct.pdf). The Code covers aspects of: formulation of research proposals; management of research data and primary materials; collaborative research; conflict of interest; supervision of research; peer review, and dissemination of research findings, publication and responsible authorship. With the expansion of research on human participation into may other sciences such as branches of engineering, computing, bio technology, genetics, artificial intelligence, machine learning, nano technology and others, the ethical issues of human research have reached a new dimension. It has to be emphasized that whatever the branch of science or discipline, if the research requires human participants, then approval of an ethics review committee is a must. Thus, it behoves on research institutes, universities, and faculties to establish ethics review committees beyond the traditional practice of having ethics review committees in medical faculties. It is necessary that members of such a committee, functions within the set terms of references, standard operating procedures, ensure confidentiality and also have appropriate training in ethics of research, approval processes and documentation. In Sri Lanka too universities have gone one step ahead to establish ethics review committees at university level to facilitate research on humans in disciplines other than health and medical practice. Time has come when universities and research institutions take steps to develop codes of conduct on research, conduct courses on such practices and ethics of research for all researchers in order to safeguard the interests and safety of both researchers and participants of research.   

Non-healing wounds are a global health problem. Substances that enhance cell proliferation, angiogenesis, and prevention of bacterial infections accelerate the wound healing process. In this study, the wound healing potential of Ziziphus oenoplia, is investigated for its ability in cell proliferation, angiogenesis, and antibacterial potential. The potential of cell proliferation enhancement (mean percent wound closure) and angiogenic response (mean vascular index) of hexanes, dichloromethane, ethyl acetate, and methanol extracts of leaf and bark of Z. oenoplia were evaluated by scratch wound assay (SWA) using Madin-Darby Canine Kidney (MDCK) cells and chick chorioallantoic membrane (CAM) assay, respectively. The antibacterial activity of these extracts was evaluated against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa by disc diffusion method. Enhanced cell proliferation was shown by the hexanes, dichloromethane, and ethyl acetate extracts of leaf and the hexanes extract of bark. An enhanced angiogenic response was shown by the methanol and ethyl acetate extracts of leaves and the methanol and hexanes extracts of bark. Dichloromethane extract of both leaf and bark showed considerable antibacterial activity against P. aeruginosa which is less susceptible to common antibiotics. SWA-directed fractionation of the hexanes extract of the leaf has resulted in the isolation and identification of an active fraction showing mean percent wound closure of 86.4% (positive control 90.2%) and mean vascular index of 34.5 (positive control 48.6). This fraction contained lupeol, α-amyrin, β-amyrin, hexacosanol, and octacosanol. The present study provides supportive evidence for the potential of wound healing enhancement of leaf and bark extracts of Z. oenoplia.

Polymer solar cells (PSCs) have attracted tremendous interest as suitable candidates for harnessing solar energy in the recent years. The inherent optoelectronic properties of the inorganic transition metal oxide, negative type cuprous oxide (n-Cu2O), makes it an attractive candidate to improve the performance of PSCs when incorporated as the electron selective transport layers (ESTLs) in the device. In this study, inverted PSCs were fabricated on stainless steel (SS) substrates with n-Cu2O as the ESTL. The n-Cu2O films were prepared by electrodeposition method, followed by annealing under ambient conditions. The active layer material was prepared as bulk heterojunction blend using regioregular poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM). Poly-(4,3-ethylene dioxythiophene):poly(styrenesulphonate) (PEDOT:PSS) was used as the hole transport layer (HTL) and the final device structure was SS/n-Cu2O/P3HT:PCBM/PEDOT:PSS/Au. Annealing of the n-Cu2O ESTL in air was optimized observing the photoactive performance of the device. Optoelectronic performance of the devices was characterized using spectral response and dark and light current-voltage (I-V) measurements. n-Cu2O ESTL- incorporated devices have absorbed more photons in the short wavelength region of 450‒600 nm with the annealing of n-Cu2O ESTL due to the reduction of electron-hole recombination. The performance of the devices was significantly increased after incorporating pre-annealed n-Cu2O ESTL at 175 °C for 30 min in air. The maximum power conversion efficiency (PCE) was 0.35%.

As a result of the development of advanced semiconductor-based optical switching devices and their commercialization, concepts and technologies in all-optical signal processing have evolved significantly in the past few years. In order to realize logical operations in photonic computing, universal gates are needed. In this research, the simple and compact all-optical NAND gate was designed using SOA and simulated at a high data rate of 10Gbps to 40 Gbps. The performance of the proposed NAND gate is shown by the numerical analysis for various input combinations and SOA. By changing wavelengths, injection currents, confinement factors, as well as optical components such as sources, amplifiers, and filters, a numerical analysis is performed. Unique results were obtained at a 10 Gbps data rate for NRZ-L user-defined bit sequences. This kind of all-optical NAND gate will be the perfect alternative in the field of optical computing to realize a high-speed optical communication network. An extinction ratio of 11.48 dB is achieved at a high-speed data rate of 10 Gbps to 40Gbps. The output spectrum of the designed NAND logic is also received for a wide input spectrum and the system responds selectively for the input wavelength at 1548.3 nm which is the probe signal wavelength.

Polycyclic aromatic hydrocarbons (PAHs) are of petrogenic or pyrogenic origin. Of the known few hundred PAHs, 16 are identified to be toxic, of which 8 are teratogenic. Of the 8, 4 are carcinogens. Among them, Benzo[a]pyrene (BaP) possesses the highest carcinogenicity and is used as a marker in toxicity studies. PAHs of petrogenic origin contaminate soil, water and air. They may occur in air associated with dust particles. PAHs of pyrogenic origin are generated during burning of wood and other organic matter. They are also produced from lipids and carbohydrates during heating of foods. PAHs are mostly identified with grilling, smoking, frying, roasting and toasting of foods. Among the foods, formation of PAHs is studied mostly in association with grilling of fish and meat, where contacts occur between the dripping lipids and naked flames. The generated PAHs get deposited back on fish and meat muscles. PAHs in smoke are deposited on food surfaces on exposure to contaminated air from the vehicle fumes and smoke curing of foods. PAHs are formed during mechanical expulsion of edible oils. Presence of markers, carcinogenic PAHs and total PAHs in different foods and their extent of formation and deposition is discussed in relation to food safety hazards and health implications. Among the local foods and food preparation habits, the role of coconut oil, smoke curing of foods and formation of PAHs even under mild conditions of heat such as manufacture of black tea are reviewed. Recommendations for future actions, research and implementing food regulations to minimize PAHs in foods are presented.  

Soil nailing is a technique which is used to reinforce and strengthen the existing ground conditions. This is done by installing closely spaced, passive, structural inclusions known as nail into the soil and these nails helps to improve the overall shear strength of soil. The nail pullout resistance is the shear stress at the grout-soil interface. The soil-nail pullout resistance depends on many parameters. Among the factors influencing the soil-nail pullout resistance, degree of saturation of the soil is an important factor. As degree of saturation of soil mass change with the moisture content of the soil, the pullout resistance may decrease during the intense rainfall. However, verification of pullout tests on soil-nail are not conducted under the worst condition. Hence, measured pullout resistance may not be a safe parameter for design. As such, in this research study, the effect of degree of saturation on pullout resistance was studied by conducting a series of laboratory tests using a laboratory pullout box. Especially designed waterproof cap was used to apply back pressure to saturate the soil within the pullout box. Variation of earth pressures close to the grouted nail were observed during the tests. It was evident from the results that higher the degree of saturation, lower the pullout resistance. Maximum pullout resistance was observed when the degree of saturation is near the optimum moisture of the soil. When the soil is sufficiently dry, lower pullout resistance was observed due to low bond strength between grout surface and surrounding dry soil.

Fluoride is beneficial for human health only in a narrow concentration range. Over the years, many analytical techniques have been developed to quantify fluoride in a variety of sample matrices. In this research, fluoride concentrations of twenty (20) natural water samples determined by SPADNS (SPA) and Eriochrome Cyanine R (ECR) colorimetric methods were evaluated to ascertain whether these methods can produce comparable fluoride concentrations. According to the paired t test for comparing individual differences, the two datasets are different at 95% confidence level suggesting that the two analytical methods produce statistically different fluoride concentrations for the analysed water samples. The potential interferences of Al3+, Ca2+, and Mg2+ on the fluoride analysis was evaluated using 0.85 mg L-1 fluoride standard solutions spiked with various amount of the above-mentioned metal ions. The highest interference was observed with Al3+ ions, which underestimated the fluoride concentration by 26% and 23% for ECR and SPA methods respectively at 20.0 mg L-1 Al3+ concentrations. The minimum interference was observed for Ca2+ ions which underestimated the fluoride concentration by 8% and 7% for ECR and SPA methods respectively at 100.0 mg L-1 Ca2+ concentrations. Acid distillation resulted in the samples spiked with Ca2+ and Mg2+ ions in the range of 0.50 to 100.0 mg L-1 reaching the theoretical concentration of 0.85 mg L-1. Acid distillation also worked well for the Al3+- fortified samples, except for Al3+ concentration at 20 mgL-1.  The efficiency of the acid distillation method was also tested with three (03) natural water samples. The fluoride concentration increased significantly after the acid distillation; however, even after the acid distillation, statistically comparable fluoride concentrations were not observed.

The southern coastal zone of Sri Lanka has been subjected to a variety of natural and anthropogenic influences over the past three decades. Understanding impacts of such influences on Land Use Land Cover (LULC) is vital for proper management of the coastal zone. This study, therefore, focused on mapping the change/s in the distribution of selected LULC in the selected sites, Bundala, Galle, Kalametiya, and Hambantota of the southern coastal zone, over last 24 years using satellite imagery. LULC maps of nine classes (mangrove, inland vegetation, marsh and grass, sand, bare land, built-up, cultivation, water, and unclassified) were created by employing an on-screen digitization technique achieving an accuracy of >70%. Trend analysis and two-sample proportion tests were used for statistical analyses, whereas geometric calculations were used for descriptive analyses. The results showed the highest overall change in LULC in Kalametiya, followed by Hambantota, Galle, and Bundala. The changes in the LULC classes are mainly attributed to the conversion of water to mangroves, marsh and grass areas in Kalametiya, water to built-up areas in Hambantota, cultivations to built-up areas in Galle, and marsh and grass areas to bare lands in Bundala. The causes of LULC changes were site specific. Trend analyses indicate the least LULC changes in Bundala possibly by 2025. The study highlights the significance of taking into account geographical dislocations when considering and anticipating the potential impacts of development projects over broader extents.  

Most of the commercial banana cultivars in Sri Lanka are susceptible to anthracnose disease. Colletotrichum musae has been known as the causal agent of banana anthracnose for decades and the pathogen has been identified using morphological characteristics. Molecular analyses based on multigene phylogenetics are now standard protocols to identify Colletotrichum species. The present study was aimed at identifying Colletotrichum species causing banana anthracnose by molecular and phenotypic characterization. Thirty-seven isolates were obtained from ripened bananas showing anthracnose symptoms, collected from different locations in the Central Province of Sri Lanka. Of them, 36 were preliminarily identified as Colletotrichum based on conidial morphology. The remaining isolate did not sporulate during the entire study period. Ten isolates taken for molecular studies consisted of eight with orange/white arial mycelia and orange conidial masses, one with a white to greyish colony and blackish clusters of ascomata, and one with a white to faint pink colour colony. DNA extracted from each isolate was subjected to multi-gene DNA sequence analysis using ITS, TUB, GAPDH and GS loci. Based on phylogenetic analyses, eight isolates were identified as Colletotrichum musae, and the other two as C. plurivorum and C. siamense. The vegetative morphology of C. plurivorum differed considerably from C. musae and C. siamense. Slight differences in colony morphology were observed among the C. musae isolates. Freshly harvested healthy bananas were artificially inoculated with isolates of C. musae or C. plurivorum and produced typical anthracnose lesions within a week. The Colletotrichum siamense isolate failed to develop anthracnose symptoms. This is the first report of C. plurivorum causing banana anthracnose.

The Mannar Basin extends over 45,000 km2 off the western coast of Sri Lanka. It has evolved due to the multiphase rifting between Indo-Lanka landmasses during the Barremian-Paleocene time. The sediment thickness of the basin ranges from about 4 to 10 km. The northern part of the basin is a targeted area for hydrocarbon exploration in Sri Lanka. Though two natural gas discoveries were made in 2011, the basin remains a frontier due to lack of well penetration and 3D seismic coverage. As a result, the depositional features of sediment in the basin are little known. This study focuses on identifying paleo depositional features in the Albian and Aptian strata using 650 km2 3D seismic data from the Mannar Basin. Root Mean Square (RMS) amplitude was used to characterize the depositional features in three-time windows on IHS Kingdom software (v.8.3). The results show the existence of a multi-level paleo submarine fan system in the Albian and Aptian strata. They are located relatively close to the western coastline compared to the fan system in the Eocene strata. The deposition of this paleo submarine fan system has taken place in a shelf marine environment and has been influenced by relatively high sea levels during the Albian and Aptian compared to the relatively low sea levels in the Paleocene and Eocene.