Expression, Characterization and Metallation Studies of Human Metallothionein Isoform 2a Using Electrospray Ionization Mass Spectrometry

Maintenance of the homeostasis of zinc (Zn) is very important in regulating bodily functions. There are over 300 Zn dependent enzymes identified, where Zn plays a structural or catalytic role. However, excess of Zn in a cell is toxic and free Zn ions are tightly controlled. Metallothioneins (MTs) are small cysteine rich proteins, which can bind up to seven Zn ions and act as a Zn reservoir. The MT2a isoform is predominantly found in the liver. My research focused on the overexpression of human MT2a in Escherichia coli and the investigation of Zn binding pathways of MT2a in vitro. At physiological pH, Zn is terminally bound to the cysteine thiols of MT2a, making bead-like structures (non-cooperative metal binding), while at low pH, Zn formed clusters bridging the terminally bound Zn (cooperative metal binding). These findings draw our attention to investigate how other essential and toxic metals bind to MT2a. Keywords: Homeostasis, zinc, metallothionein (MT), metallothionein 2a (MT2a), non-cooperative, cooperative, Zn binding pathwa

Validity of a food frequency questionnaire to assess nutritional intake among Sri Lankan adults

Sri Lanka is undergoing nutritional transition and diet-related chronic diseases are emerging as an important health problem. Currently, no validated food frequency questionnaire (FFQ) exists to measure habitual dietary intake of Sri Lankan adults. The purpose of the study is to assess the validity of a semi-quantitative FFQ and 7-day weighed-intake dietary records (7DWR), designed to assess dietary intake among Sri Lankan adults. Dietary intake was measured using both a FFQ and 7DWR. The FFQ consisted of 8 food groups containing the main foods comprising the diet of Sri Lankan adults, a total of 85 items and 12 color photographs to identify serving size. One hundred healthy adults were randomly recruited from a community sample and administrated the FFQ followed by completion of the 7DWR. Paired sample t tests, Pearson’s correlation coefficients, kappa test and Bland–Altman analysis were conducted to determine correlation and the level of agreement for energy and micronutrients. Seventy-seven participants completed both the FFQ and 7DWR. Estimated mean energy intake (SD) from FFQ (1794 ± 398 kcal) and 7DWR (1698 ± 333 kcal, p < 0.001) were significantly different due to a significant overestimation of carbohydrate (11.5 g/day, p < 0.001) and to some extent fat (5.7 g/day, ns). Significant positive correlations (p < 0.05) were found between the FFQ and 7DWR for energy (r = 0.39), carbohydrate (r = 0.47), protein (r = 0.26), fat (r = 0.17) and dietary fiber (r = 0.32). Bland–Altman graphs indicated fairly good agreement between methods with no relationship between bias and average intake of each nutrient examined. Based on these findings, the FFQ appears to be an acceptable tool for assessing the nutrient intake of Sri Lankans and will assist proper categorization of individuals by dietary intake

Modified correlation entropy estimation for a noisy chaotic time series

A method of estimating the Kolmogorov-Sinai (KS) entropy, herein referred to as the modified correlation entropy, is presented. The method can be applied to both noise-free and noisy chaotic time series. It has been applied to some clean and noisy data sets and the numerical results show that the modified correlation entropy is closer to the KS entropy of the nonlinear system calculated by the Lyapunov spectrum than the general correlation entropy. Moreover, the modified correlation entropy is more robust to noise than the correlation entropy. © 2010 American Institute of Physics.published_or_final_versio

A method of estimating the noise level in a chaotic time series

An attempt is made in this study to estimate the noise level present in a chaotic time series. This is achieved by employing a linear least-squares method that is based on the correlation integral form obtained by Diks in 1999. The effectiveness of the method is demonstrated using five artificial chaotic time series, the H́non map, the Lorenz equation, the Duffing equation, the Rossler equation and the Chua's circuit whose dynamical characteristics are known a priori. Different levels of noise are added to the artificial chaotic time series and the estimated results indicate good performance of the proposed method. Finally, the proposed method is applied to estimate the noise level present in some real world data sets. © 2008 American Institute of Physics.published_or_final_versio

Prevalence, Trends and Associated Socio-Economic Factors of Obesity in South Asia

Aim: Worldwide obesity levels have increased unprecedentedly over the past couple of decades. Although the prevalence, trends and associated socio-economic factors of the condition have been extensively reported in Western populations, less is known regarding South Asian populations. Methods: A review of articles using Medline with combinations of the MeSH terms: 'Obesity', ‘Overweight’ and ‘Abdominal Obesity’ limiting to epidemiology and South Asian countries. Results: Despite methodological heterogeneity and variation according to country, area of residence and gender, the most recent nationally representative and large regional data demonstrates that without any doubt there is an epidemic of obesity, overweight and abdominal obesity in South Asian countries. Prevalence estimates of overweight and obesity (based on Asian cut-offs: overweight ≥ 23 kg/m[superscript]2, obesity ≥ 25 kg/m[superscript]2) ranged from 3.5% in rural Bangladesh to over 65% in the Maldives. Abdominal obesity was more prevalent than general obesity in both sexes in this ethnic group. Countries with the lowest prevalence had the highest upward trend of obesity. Socio-economic factors associated with greater obesity in the region included female gender, middle age, urban residence, higher educational and economic status. Conclusion: South Asia is significantly affected by the obesity epidemic. Collaborative public health interventions to reverse these trends need to be mindful of many socio-economic constraints in order to provide long-term solutions

Audiovisual Speech-In-Noise (SIN) Performance of Young Adults with ADHD

Adolescents with Attention-deficit/hyperactivity disorder (ADHD) have difficulty processing speech with background noise due to reduced inhibitory control and working memory capacity (WMC). This paper presents a pilot study of an audiovisual Speech-In-Noise (SIN) task for young adults with ADHD compared to age-matched controls using eye-tracking measures. The audiovisual SIN task consists of varying six levels of background babble, accompanied by visual cues. A significant difference between ADHD and neurotypical (NT) groups was observed at 15 dB signal-to-noise ratio (SNR). These results contribute to the literature of young adults with ADHD.Comment: To be published in Symposium on Eye Tracking Research and Applications (ETRA '20 Short Papers), 6 pages, 3 figures, 2 table

Influence of Computer Assisted Language Learning (CALL) in the Acquisition of English as a Second Language by Polytechnic Students of Sri Lanka

Levy, M. (1997) explains Computer Assisted Language Learning (CALL) as“the search for and the study of applications of the computer in language teaching andlearning.” This research investigates the effectiveness of CALL in conducting Englishcourses for polytechnic students in Sri Lanka with special reference to studentsfollowing Higher National Diploma in Engineering, Management and English at SriLanka Institute Advanced Technological Education.The hypothesis that CALL made a positive impact on the polytechnic studentsthat learnt English as a second language was supported on the objectives that motivationof the students to follow the course was sustained, that their level of attendanceincreased and that their performance in the language tests improved. Data used in thiswork was collected via questionnaires forwarded to the members of the sample selectedas well as observations of the instructors/lecturers that represented the three courses.At the end of data analysis this research found noticeable improvement in theperformance of students in English since the incorporation of CALL in English languageprogrammes followed by them. The student autonomy, authenticity of material andtechnological paraphernalia that CALL involves seemed to take their appeal resulting inthe development of their language skills. Advantages of using CALL in languageprogrammes of polytechnic students led this research to advocate the incorporation ofInternet and other language software into second language courses and at the same timeit emphasizes adequate training and awareness building initiatives for the staffconducting these courses, for enabling them to handle the technical interruptions andtrouble shooting promptly for delivering and ensuring a satisfactory learningexperience/environment for students learning English as their second language.Key words: Polytechnic, Appeal, Authenticity, Impact, Trainin

Synthesis and characterization of mixed oxide nanowires for gas sensing

A healthy and long-lasting life is the utmost wish of any living being thus aging. The aging phenomenon cannot be stopped but may be controlled to some extent when we live in appropriate environments. Usually, the outdoor environment is polluted by two means natural events (windblown dust, volcano eruptions, etc.) and man-made ones (burning of facile fuels, factories, volatile organic compounds, etc.). Pollution due to harmful air such as sulfur oxides (SO2), nitrogen oxides (NOX), carbon monoxide (CO), ammonia (NH3), methane (CH4), and volatile organic compounds (VOCs) is one of the significant issues since it is more sensitive to compromising the natural ecosystem and environment. So, exposure to these compounds worsens the aging phenomena of the living being (headache, fainting, skin and eye irradiation, respiratory infections, heart disease, lung cancer, and even superficial death). Therefore, it is necessary the detection these compounds in the environment. Accordingly, metal oxides (MOXs) gas sensors have conventionally been employed to detect and quantify harmful gases in both indoor and outdoor environments. However, one of the major problems with these sensors is achieving selective detection. Herein, we propose a novel design with two metal oxides (ZnO and Co3O4) that provide very high gas response together with superior selectivity. The proposed structure is a one-dimensional (1D) metal oxide composite; Co3O4/ZnO nanowires. The composite was prepared by in-situ thermal oxidation of metallic Co thin layer (50 nm) and evaporation of ZnO powder at a temperature of 800 ᵒC at a pressure of 0.15 mbar. The pressure was maintained by a controlled mixture of O2 and Ar. The morphological, compositional, and structural analyses are evidence of the successful growth of the Co3O4/ZnO composite nanowire with the root of Co3O4 and the tip with Pt (catalyzer) and Co3O4. The gas sensing characterization shows exciting sensing functionality towards acetone (C3H6O) compared to that of tested gases (C2H5OH, H2S, NH3, CO, NO2, and H2). The reported highest response (ΔG/G; G is the conductance) was above the value of 5000 toward 50 ppm (parts per million) C3H6O at 40 RH% air when working at 250 °C with the potential of detecting sub ppb (parts per billion) concentration levels of C3H6O. The very high C3H6O sensing performance together with exceptionally high selectivity of the sensor ascribed to Pt nanoparticle and the Co3O4 section on the tip of the Co3O4/ZnO. Moreover, the formation of heterojunctions, synergistic gas sensing, and the catalytic activity of the proposed design enhances the response of the sensors. Accordingly, scanning electron microscopic (SEM), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) characterization, and the sensing mechanisms are comprehensively discussed at the conference