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Mumbai Monday, 4 June, 2018 - 14:04

Researchers from Indian Institute of Technology Bombay, Mumbai are studying the strange phenomenon known as urban heat islands, which leads to a sharp temperature difference between urban and metropolitan areas and the surrounding rural areas, due to human activities. The study also proposes measures to reduce the dire effects of the phenomenon.

Urban Heat Islands (UHI) is a phenomenon where the temperature in urban and metropolitan areas gets significantly higher than the surrounding rural areas. “Heat island forms when the temperature difference between urban area and rural area temperature is significant. The temperature differences are often largest during calm, clear evenings because rural areas cool off faster at night than cities” explain the authors of the study.

Several factors lead to such a disparity in temperatures, like larger stretches of tarred roads absorbing more solar radiation, extensive use of materials like concrete and asphalt, and decrease in amount of vegetation. Adding to these woes is the factor of urbanization, where a population slowly shifts from rural areas to urban areas. Such a mass movement of population has also had an adverse effect on the climatic patterns in our environment.

“It (urbanization) is impacting the temperature profile of the region, the rainfall pattern, the albedo (a measure of the amount of solar radiation reflected), relative humidity, and the radiation pattern” remark the authors of the study.

Changes to the micro –scale environment due to concretization, urban activity and increase in vehicular density are known to cause changes in the macro-scale environment, in urban pockets.

For their study, the researchers studied the outdoor thermal environment at the micro-scale in the metropolitan areas of Mumbai. Using ENVI-met software, the researchers simulated the micro-climate, and explored measures to mitigate the effects of UHI. The study also explores the importance of greening or increasing vegetation cover in mitigating the harmful effects of the temperature disparity.

The study reveals the importance of vegetation in controlling the rising temperature in cities. It recommends the use of vertical walls, also known as living walls or green walls-- which are self sufficient vertical gardens attached to the exterior or interior of buildings. Apart from the green walls, the study also suggests dense vegetation cover and presence of forests in cities to avoid effects of UHI.

Section: General, Science, News Source:
ಬೆಂಗಳೂರು Friday, 1 June, 2018 - 07:00

ಬ್ಯಾಕ್ಟೀರಿಯಾದಿಂದ ಉಂಟಾಗುವ ಪ್ರತಿಜೀವಕ ನಿರೋಧಕತೆಯ ಬಗ್ಗೆ ಮೂರು ಭಾಗಗಳಲ್ಲಿ ಮೂಡಲಿದೆ. ಮೊದಲ ಭಾಗದಲ್ಲಿ ಅದರ ಕಾರಣಗಳು, ಪ್ರತಿಜೀವಕ ನಿರೋಧಕತೆಯಿಂದ ಉಂಟಾಗುವ ತೊಂದರೆಗಳು ಹಾಗು ಭಾರತದಲ್ಲಿ ಈ ಸಮಸ್ಯೆಯ ತೀವ್ರತೆಯ ಬಗ್ಗೆ ತಿಳಿಯಬಹುದು. 

೨೦೦೮ರಲ್ಲಿ, ಒಬ್ಬ ವ್ಯಕ್ತಿಯು ಮೂತ್ರಕೋಶದ ಸೋಂಕಿನಿಂದ ಆಸ್ಪತ್ರೆಗೆ ದಾಖಲಾದನು; ಈ ಮೂತ್ರಕೋಶದ ಸೋಂಕು ಎಂಬುದು ಮೂತ್ರವಿಸರ್ಜನೆಯ ಸಮಯದಲ್ಲಿ ಉರಿಯುವ ಸಂವೇದನೆಗೆ ಕಾರಣವಾಗುವ ಬ್ಯಾಕ್ಟೀರಿಯಾದಿಂದ ಉಂಟಾದ ಸಾಮಾನ್ಯ ಸಮಸ್ಯೆ. ಸಾಮಾನ್ಯವಾಗಿ, ಒಂದು ಸುತ್ತು ಪ್ರತಿಜೀವಕಗಳು, ರೋಗಿಯನ್ನು ಈ ಸಮಸ್ಯೆಯಿಂದ ಮುಕ್ತವಾಗಿಸಬೇಕು. ಆದರೆ ಈ ಪ್ರಕರಣದಲ್ಲಿ ಗಮನಾರ್ಹ ಎನಿಸಿದ್ದು ಏನೆಂದರೆ, ಈಗ ಅಸ್ತಿತ್ವದಲ್ಲಿರುವ ಬೃಹತ್ ವ್ಯಾಪ್ತಿಯ ಪ್ರತಿಜೀವಕಗಳೊಂದಿಗೆ ಚಿಕಿತ್ಸೆ ನೀಡುತ್ತಿದ್ದರೂ ಸಹ, ಸೋಂಕು ಹಾಗೇ ಉಳಿದುಕೊಂಡಿತ್ತು! ಆಶ್ಚರ್ಯಚಕಿತರಾದ ವೈದ್ಯರು, ಸೋಂಕಿಗೆ ಕಾರಣವಾದ ಬ್ಯಾಕ್ಟೀರಿಯಾವನ್ನು ಕೂಲಂಕುಶವಾಗಿ ಪರೀಕ್ಷಿಸಿದರು.

ಹೀಗೆ ಪರೀಕ್ಷಿಸಲಾದ ಬ್ಯಾಕ್ಟೀರಿಯಾದಲ್ಲಿ ಒಂದು ಹೊಸ ಜೀನ್ ಇರುವುದನ್ನು ಅವರು ಕಂಡುಕೊಂಡರು; ಈ ಜೀನ್ ಇರುವ ಕಾರಣದಿಂದ, ಪ್ರತಿಜೀವಕಗಳನ್ನು ಮೆಟ್ಟಿ ನಿಲ್ಲಲು ಆ ಬ್ಯಾಕ್ಟೀರಿಯಾಗೆ ಸಾಧ್ಯವಾಯಿತು. ಇಂತಹಾ ರೋಗಾಣುಗಳಿಗೆ 'ಸೂಪರ್ ಬಗ್' ಎಂಬ ಹೆಸರಿದೆ. ಈ 'ಸೂಪರ್ ಬಗ್'ಗಳು ಪ್ರತಿಜೀವಕಗಳ ಪರಿಣಾಮಗಳಿಗೆ ಪ್ರತಿರೋಧಕ ಗುಣವನ್ನು ಬೆಳೆಸಿಕೊಂಡುಬಿಡುತ್ತವೆ. ಹಾಗಾಗಿ, ಅವುಗಳನ್ನು ಹಲವಾರು ಬಗೆಯ ಪ್ರತಿಜೀವಕಗಳ ಬಳಕೆಯಿಂದಲೂ ನಾಶ ಮಾಡಲು ಆಗುವುದಿಲ್ಲ. ಪ್ರತಿ ವರ್ಷ ಸುಮಾರು ೨ ದಶಲಕ್ಷ ಜನರು ಇಂತಹ 'ಸೂಪರ್ ಬಗ್' ಸೋಂಕುಗಳಿಗೆ ಒಳಪಟ್ಟು, ಅವರಲ್ಲಿ ಸುಮಾರು ೨೩,೦೦೦ ಜನರು ತಮ್ಮ ಪ್ರಾಣವನ್ನೇ ತೆತ್ತಬೇಕಾಗಿ ಬಂದಿದೆ ಎನ್ನುತ್ತದೆ ಅಮೆರಿಕಾದ 'ರೋಗ ತಡೆಗಟ್ಟುವಿಕೆ ಹಾಗೂ ನಿಯಂತ್ರಣ ಕೇಂದ್ರ'ದ ದತ್ತಾಂಶ.

ಈ ಸೋಂಕನ್ನು ಉಂಟುಮಾಡುವ ಬ್ಯಾಕ್ಟೀರಿಯಾದಲ್ಲಿ ಇರುವ ಆ ನಿರೋಧಕ ಜೀನನ್ನು 'ನ್ಯೂ ಡೆಲ್ಲಿ-ಮೆಟಾಲೋ-ಬೀಟಾ-ಲ್ಯಾಕ್ಟಮಾಸ್' ಎಂದು ಹೆಸರಿಸಲಾಯಿತು; ಇದಕ್ಕೆ ಕಾರಣ, ಆ ಸ್ವೀಡಿಷ್ ವ್ಯಕ್ತಿ ನವದೆಹಲಿಗೆ ಭೇಟಿ ನೀಡಿದ ನಂತರವೇ ಆತನಿಗೆ ಈ ಸೋಂಕು ಕಾಡಿದ್ದು; ಆ ಪ್ರಕರಣದ ನಂತರ, ದೇಶಾದ್ಯಂತ ಅನೇಕ ಸೋಂಕುಕಾರಕ ಬ್ಯಾಕ್ಟೀರಿಯಾದಲ್ಲಿ ಎನ್.ಡಿ.ಎಂ-೧ ಎಂಬ ಈ ಜೀನನ್ನು ಗುರುತಿಸಲಾಗಿದೆ; ಈ ಜೀನ್ ನ ಕಾರಣದಿಂದ ಅನೇಕ ಪ್ರಬಲ ಮತ್ತು ಪ್ರಸಿದ್ಧವಾದ ಪ್ರತಿಜೀವಕಗಳು ಅಪ್ರಯೋಜಕಗಳೆನಿಸಿವೆ.

ಪ್ರತಿಜೀವಕಗಳು - ಎರಡು ಅಲಗಿನ ಬಾಕು
ಕಳೆದ ಶತಮಾನದಿಂದ, ಬ್ಯಾಕ್ಟೀರಿಯಾದ ಬಗ್ಗೆ ನಮ್ಮ ತಿಳುವಳಿಕೆ ಹೆಚ್ಚುತ್ತಿರುವ ಕಾರಣದಿಂದ, ಅವುಗಳ ವಿರುದ್ಧವಾಗಿ ಹೆಚ್ಚು ಪರಿಣಾಮಕಾರಿಯಾದ ಔಷಧಗಳನ್ನು ವಿನ್ಯಾಸಗೊಳಿಸಲು ಸಾಧ್ಯವಾಯಿತು. 'ಪ್ರತಿಜೀವಕ - ಪೂರ್ವ' ಯುಗದಲ್ಲಿ ಸಾವಿರಾರು ಜನರ ಸಾವಿಗೆ  ಕಾರಣವಾದ ಟೈಫಾಯಿಡ್, ಕ್ಷಯ, ಕಾಲರಾ, ಮತ್ತು ನ್ಯುಮೋನಿಯಂತಹ ಬ್ಯಾಕ್ಟೀರಿಯಾದ ಸೋಂಕುಗಳನ್ನು, ಇಂದು, ಪ್ರತಿಜೀವಕಗಳ ಮೂಲಕ ಪರಿಣಾಮಕಾರಿಯಾಗಿ ಗುಣಪಡಿಸಬಹುದಾಗಿದೆ. ಇದರ ಪರಿಣಾಮವಾಗಿ, ಪ್ರತಿಜೀವಕದ ಬಳಕೆಯಿರುವ ಈ ಯುಗದಲ್ಲಿ ಜನಿಸಿದ ವ್ಯಕ್ತಿಯ ಸರಾಸರಿ ಜೀವಿತಾವಧಿ ೭೧ ವರ್ಷಗಳು; ೧೯೫೦ರ ದಶಕಕ್ಕೂ ಮುಂಚೆ ಜನಿಸಿದ ವ್ಯಕ್ತಿಯ ಸರಾಸರಿ ಜೀವಿತಾವಧಿಯು ಕೇವಲ ೪೭ ವರ್ಷಗಳಿದ್ದು, ಇದಕ್ಕೆ ಹೋಲಿಸಿದರೆ, ೫೦% ನಷ್ಟು ಜೀವಿತಾವಧಿಯಲ್ಲಿನ ಹೆಚ್ಚಳವು ದಿಗ್ಭ್ರಮೆಯುಂಟುಮಾಡುತ್ತದೆ; ಇದಕ್ಕೆ ಕಾರಣವಾದ 'ಪ್ರತಿಜೀವಕ'ಗಳೆಂದು ಕರೆಯಲ್ಪಡುವ ಪವಾಡಕ್ಕೆ ಧನ್ಯವಾದಗಳನ್ನು ಹೇಳಲೇಬೇಕು.

ಸರ್ ಅಲೆಕ್ಸಾಂಡರ್ ಫ್ಲೆಮಿಂಗ್ ಅವರಿಗೆ ನೊಬೆಲ್ ಪ್ರಶಸ್ತಿ ತಂದುಕೊಟ್ಟ 'ಪೆನಿಸಿಲಿನ್'ನ ಸಂಶೋಧನೆಯು 'ಪ್ರತಿಜೀವಕಗಳ ಯುಗದ' ಆರಂಭವನ್ನು ಘೋಷಿಸಿತು. ಅಂದಿನಿಂದ, ನಾವು ಬ್ಯಾಕ್ಟೀರಿಯಾದ ಸೋಂಕಿನಿಂದ ಉಂಟಾಗುವ ರೋಗಗಳ ಬೃಹತ್ ಶ್ರೇಣಿಯನ್ನು ಸುಲಭವಾಗಿ ಗುಣಪಡಿಸುವ ಸುಮಾರು ೧೦೦ ವಿಭಿನ್ನ ಪ್ರತಿಜೀವಕಗಳನ್ನು ಅಭಿವೃದ್ಧಿಪಡಿಸಿದ್ದೇವೆ. ಈ ಪ್ರತಿಜೀವಕಗಳು ಸುಲಭವಾಗಿ ಕೈಗೆಟುಕುವ ದರದಲ್ಲಿ ಲಭ್ಯವಿರುವ ಕಾರಣದಿಂದ ಸರ್ವತ್ರವಾಗಿ ಮತ್ತು ವ್ಯಾಪಕವಾಗಿ ಬಳಕೆಯಾಗುತ್ತಿದ್ದು ಅದ್ಭುತ ಪರಿಣಾಮಕಾರಿತ್ವವನ್ನೂ ಹೊಂದಿವೆ.

ಕೇವಲ ಮಾನವನನ್ನು ಕಾಡುವ ಕಾಯಿಲೆಗಳನ್ನು ನಿವಾರಿಸಲು ಮಾತ್ರ ಪ್ರತಿಜೀವಕಗಳನ್ನು ಬಳಸುವುದಷ್ಟೇ ಅಲ್ಲ; ಹಸು, ಎಮ್ಮೆ, ಕೋಳಿ, ಹಂದಿ ಮತ್ತು ಮೀನುಗಳಂತಹ ಇತರ ಪ್ರಾಣಿಗಳಲ್ಲೂ ಸಹ ನಿಯಮಿತವಾಗಿ ರೋಗಗಳ ವಿರುದ್ಧ ಹೋರಾಡಲು ಅಥವಾ ಅವುಗಳನ್ನು ತಡೆಯಲು, ಪ್ರತಿಜೀವಕಗಳ ಮೂಲಕ ಚಿಕಿತ್ಸೆ ನೀಡಲಾಗುತ್ತದೆ. ಇದು ಇಳುವರಿಯನ್ನು ಸುಧಾರಿಸಲು ಮತ್ತು ನಮ್ಮ ಪ್ರಾಣಿಗಳನ್ನು ಆರೋಗ್ಯಕರವಾಗಿ ಇರಿಸಿಕೊಳ್ಳಲು ಸಹಾಯ ಮಾಡುತ್ತದೆ; ಆದರೆ ಈ ಪ್ರತಿಜೀವಕಗಳು ಆಹಾರ ಸರಪಳಿಯ ಭಾಗವಾಗಿ ಪ್ರಾಣಿಜನ್ಯ ಉತ್ಪನ್ನಗಳ ಮೂಲಕ ನಮ್ಮ ದೇಹಗಳನ್ನು ಪ್ರವೇಶಿಸುತ್ತವೆ.

ಪ್ರತಿಜೀವಕಗಳ ಬಳಕೆಗೆ ಅಥವಾ ದುರ್ಬಳಕೆಗೆ ಮತ್ತೊಂದು ದುರಂತದ ಉಪಕಥೆ ಇದೆ. ಎಲ್ಲಾ ವಿಧದ ಪ್ರತಿಜೀವಕಗಳಿಗೆ ಹೆಚ್ಚು ಹೆಚ್ಚು ಬ್ಯಾಕ್ಟೀರಿಯಾಗಳು ನಿರೋಧಕವಾಗುತ್ತಿರುವುದರಿಂದ, ರೋಗ ಗುಣಪಡಿಸುವ ದಕ್ಷತೆಯು ಕಡಿಮೆಯಾಗುತ್ತಿದೆ ಎಂದು ಅಂಕಿಅಂಶಗಳು ತೋರಿಸುತ್ತವೆ. ಸಂಕ್ಷಿಪ್ತವಾಗಿ ಹೇಳುವುದಾದರೆ, ಬ್ಯಾಕ್ಟೀರಿಯಾಗಳು ಪ್ರಬಲವಾಗುತ್ತಿವೆ ಮತ್ತು ಪ್ರತಿಜೀವಕಗಳು ಸೋಲೊಪ್ಪಿಕೊಳ್ಳಲು ಪ್ರಾರಂಭಿಸಿವೆ. ಆದರೆ ಒಮ್ಮೆ ಅವುಗಳನ್ನು ಕೊಲ್ಲಲು ಬಳಸಿದ ಔಷಧಿಗಳಿಗೇ ಈ ಬ್ಯಾಕ್ಟೀರಿಯಾಗಳು ಹೇಗೆ ಪ್ರತಿರೋಧವನ್ನು ಉಂಟುಮಾಡುತ್ತಿವೆ? ಇದಕ್ಕೆ ಉತ್ತರವು ಜೀವ ವಿಕಾಸದಲ್ಲಿದೆ.

'ಬಗ್' ನಿಂದ 'ಸೂಪರ್ ಬಗ್' ವಿಕಸನ
ಸಾಮಾನ್ಯ ರೋಗಾಣುವನ್ನು ಆಂಗ್ಲ ಆಡುಭಾಷೆಯಲ್ಲಿ 'ಬಗ್' ಎಂದೂ, ಪ್ರತಿಜೀವಕ ನಿರೋಧಕ ರೋಗಾಣುವನ್ನು 'ಸೂಪರ್ ಬಗ್' ಎಂದೂ ಕರೆಯುತ್ತಾರೆ. 'ಬಗ್'ಗಳು 'ಸೂಪರ್ ಬಗ್'ಗಳು ಹೇಗಾದವು ಎಂದು ತಿಳಿದುಕೊಳ್ಳುವ ಸಲುವಾಗಿ, ವಿಕಸನಕ್ಕೆ ಒಳಪಡುವ ಮೊದಲು, ಬ್ಯಾಕ್ಟೀರಿಯ ವಿರುದ್ಧ ಪ್ರತಿಜೀವಕಗಳು ಹೇಗೆ ಕೆಲಸ ಮಾಡುತ್ತವೆ ಎಂಬುದರ ಬಗ್ಗೆ ಸಂಕ್ಷಿಪ್ತವಾಗಿ ತಿಳಿದುಕೊಳ್ಳೋಣ. ಕೆಲವೊಂದು ಪ್ರತಿಜೀವಕಗಳು ಬ್ಯಾಕ್ಟೀರಿಯಾದ ಬೆಳವಣಿಗೆಯನ್ನು ತಡೆಯುವುದರ, ಮೂಲಕ ಅವುಗಳ ಸಂತತಿ ನಾಶ ಮಾಡುತ್ತವೆ; ಮತ್ತೂ ಕೆಲವು ಪ್ರತಿಜೀವಕಗಳು, ಬ್ಯಾಕ್ಟೀರಿಯ ತಮ್ಮ ಉಳಿವಿಗಾಗಿ ಉತ್ಪಾದಿಸುವ ಅಗತ್ಯ ಪ್ರೋಟೀನ್ಗಳ ಉತಾದನೆಯಲ್ಲಿ ಮಧ್ಯಪ್ರವೇಶಿಸುವುದರ ಮೂಲಕ, ಅವುಗಳನ್ನು ಕೊಲ್ಲುತ್ತವೆ. ಅನೇಕ ಬ್ಯಾಕ್ಟೀರಿಯ, ಶಿಲೀಂಧ್ರ ಮತ್ತು ಇತರ ಸೂಕ್ಷ್ಮಾಣು ಜೀವಿಗಳು ನೈಸರ್ಗಿಕವಾಗಿ ಪ್ರತಿಜೀವಕಗಳನ್ನು ಉತ್ಪತ್ತಿ ಮಾಡುತ್ತವೆ. ವಾಸ್ತವವಾಗಿ, ಪೆನ್ಸಿಲಿನ್ ಎಂಬ ಮೊದಲ ಪ್ರತಿಜೀವಕವು 'ಪೆನ್ಸಿಲಿಯಂ ನೋಟೆಟಂ' ಎಂಬ ಶಿಲೀಂಧ್ರವು ಸ್ರವಿಸಲಾದ ದ್ರವದಲ್ಲೆ ಕಂಡುಹಿಡಿಯಲ್ಪಟ್ಟಿತು.

ಬ್ಯಾಕ್ಟೀರಿಯಾವನ್ನು ಸಂಪೂರ್ಣವಾಗಿ ನಾಶಮಾಡಬಹುದಾದ ಪ್ರತಿಜೀವಕಗಳು ಬಹಳ ಪ್ರಬಲವಲ್ಲವೇ? ಇಂತಹ ಪ್ರತಿಜೀವಕಗಳಿಗೆ ಬ್ಯಾಕ್ಟೀರಿಯಾವು ಹೇಗೆ ಪ್ರತಿರೋಧವನ್ನು ಹುಟ್ಟಿಸಿಕೊಳ್ಳುತ್ತದೆ? ಕೆಲವು ಬ್ಯಾಕ್ಟೀರಿಯಾಗಳು ನೈಸರ್ಗಿಕವಾಗಿ ಪ್ರತಿಜೀವಕಗಳಿಗೆ ನಿರೋಧಕವಾಗಿದ್ದು, ಮತ್ತೂ ಕೆಲವು ಕಾಲಾಂತರದಲ್ಲಿ ಪ್ರತಿರೋಧವನ್ನು ಪಡೆದುಕೊಳ್ಳುತ್ತವೆ. ನೈಸರ್ಗಿಕ ಆಯ್ಕೆಯ ಸಿದ್ಧಾಂತದ ಪ್ರಕಾರ, ಜೀವಿಗಳು ನೈಸರ್ಗಿಕವಾಗಿ ಅವುಗಳ ಪರಿಸರದಲ್ಲಿ ಬದುಕುಳಿಯಲು ಅವಶ್ಯಕವಾದ ಗುಣಲಕ್ಷಣಗಳನ್ನು ಅಭಿವೃದ್ಧಿಪಡಿಸಲು, ಕಾಲಕಾಲಕ್ಕೆ ವಿಕಸನಗೊಳ್ಳುತ್ತವೆ. ಪ್ರತಿಜೀವಕಗಳು ಇಂತಹ ಸವಾಲಿನ ಪರಿಸರವನ್ನು ಬ್ಯಾಕ್ಟೀರಿಯಾಕ್ಕೆ ಒದಗಿಸುತ್ತವೆ; ಹಾಗಾಗಿ ಅಲ್ಲಿ ಬದುಕುಳಿಯುವುದು ಕೇವಲ ಪ್ರತಿಜೀವಕಗಳಿಗೆ ನಿರೋಧಕವಾಗಿರುವ ಬ್ಯಾಕ್ಟೀರಿಯ ಅಥವಾ ಬದುಕುವ ಸಲುವಾಗಿ ಕಾಲಾಂತರದಲ್ಲಿ  ಪ್ರತಿರೋಧವನ್ನು ಬೆಳೆಸಿಕೊಳ್ಳುವ ಬ್ಯಾಕ್ಟೀರಿಯ.

ಬ್ಯಾಕ್ಟೀರಿಯಾದ ಮೇಲೆ ಈ 'ಆಯ್ಕೆಯ ಒತ್ತಡ'ವು ಚೆನ್ನಾಗಿ ಕೆಲಸ ಮಾಡುತ್ತದೆ. ಪ್ರತಿ ಬಾರಿಯೂ ಬ್ಯಾಕ್ಟೀರಿಯಾದ ವಿಭಜನೆಯಾದಾಗ, ಸ್ವಾಭಾವಿಕವಾಗಿ ಜೀನುಗಳ ರೂಪಾಂತರ ಆಗುತ್ತದೆ. ಅಂದರೆ, ಅದರ ಡಿಎನ್ಎ ಅನುಕ್ರಮದಲ್ಲಿ ಯಾದೃಚ್ಛಿಕ ಬದಲಾವಣೆ ಆಗುತ್ತದೆ. ಹೀಗೆ ರೂಪಾಂತರ ಪ್ರಕ್ರಿಯೆಯಲ್ಲಿರುವಾಗ ಆ ಬ್ಯಾಕ್ಟೀರಿಯಾದ ಮೇಲೆ ನೀವು ಪ್ರತಿಜೀವಕವನ್ನು ಸಿಂಪಡಿಸಿದರೆ, ಆಗ ಬ್ಯಾಕ್ಟೀರಿಯಾದ ಡಿಎನ್ಎ ಆನುವಂಶಿಕ ರೂಪಾಂತರಕ್ಕೆ ಒಳಗಾಗುತ್ತದೆ; ಪ್ರತಿಜೀವಕಗಳನ್ನು ನಿಷ್ಪರಿಣಾಮಕಾರಿಯಾಗಿ ಮಾಡುವ ಜೀವರಾಸಾಯನಿಕ ವಸ್ತುವನ್ನು ಉತ್ಪತ್ತಿ ಮಾಡಲು ಅಥವಾ ಆ ಪ್ರತಿಜೀವಕವನ್ನು ಜೀವಕೋಶದಿಂದ ಹೊರಹಾಕಲು ಬೇಕಾದ  ವಸ್ತುವನ್ನು ಉತ್ಪತ್ತಿ ಮಾಡಲು ಶಕ್ತಗೊಳಿಸುತ್ತದೆ. ಈ ರೂಪಾಂತರಗಳನ್ನು ಅನುವಂಶಿಕವಾಗಿ ಪಡೆದುಕೊಳ್ಳುವಲ್ಲಿ ಯಶಸ್ವಿಯಾಗುವ ಬ್ಯಾಕ್ಟೀರಿಯಾ, ಉಳಿಯುತ್ತವೆ ಮತ್ತು ಬೆಳೆಯುತ್ತವೆ; ಆದರೆ ಇತರ ಬ್ಯಾಕ್ಟೀರಿಯಾ ಸಾಯುತ್ತವೆ. ಕಾಲಾಂತರದಲ್ಲಿ, ಪ್ರತಿಜೀವಕ ನಿರೋಧಕ ಬ್ಯಾಕ್ಟೀರಿಯಾ ನಿರೋಧಕವಲ್ಲದ ಬ್ಯಾಕ್ಟೀರಿಯಾವನ್ನು ಮೀರಿಸುತ್ತವೆ ಮತ್ತು ಪ್ರತಿಜೀವಕಗಳನ್ನು ನಿಷ್ಪರಿಣಾಮಕಾರಿಯಾಗಿಸುತ್ತವೆ.

ಪ್ರತಿಜೀವಕ ನಿರೋಧಕ ಸೂಪರ್ ಬಗ್ ಸಮಸ್ಯೆಯನ್ನು ಮತ್ತಷ್ಟು ಸಂಕೀರ್ಣ ಮತ್ತು ಆಸಕ್ತಿದಾಯಕ ವಿಷಯವನ್ನಾಗಿ ಮಾಡುವುದು ಏನೆಂದರೆ, ತಮ್ಮ ವಂಶವಾಹಿಯನ್ನು ತಮ್ಮ ಸಂತತಿಗೆ ಮಾತ್ರ ವರ್ಗಾಯಿಸುವ ಮಾನವರಂತಲ್ಲದ ಬ್ಯಾಕ್ಟೀರಿಯ, ಯಾವುದೇ ಬ್ಯಾಕ್ಟೀರಿಯ ಅಥವಾ ಮತ್ತಿತರ ಸೂಕ್ಷ್ಮಾಣು ಜೀವಿಗೆ ತಮ್ಮ ಆನುವಂಶಿಕ ಸಾಮಗ್ರಿಯನ್ನು ವರ್ಗಾಯಿಸುತ್ತದೆ. ಒಂದು ಸೂಪರ್ ಬಗ್ ಇರುವ ಸಮುದಾಯದಲ್ಲಿ ಕಾಲಾಂತರದಲ್ಲಿ, ಜೀನ್-ವರ್ಗಾವಣೆಯ ಮೂಲಕ, ಹೆಚ್ಚಿನ ಸಂಖ್ಯೆಯಲ್ಲಿ 'ಸೂಪರ್ ಬಗ್'ಗಳು ತಯಾರಾಗುತ್ತವೆ.

ಪ್ರತಿಜೀವಕಗಳ ಪ್ರತಿರೋಧದ ಪ್ರಮಾಣವನ್ನು ಪ್ರಮಾಣೀಕರಿಸುವ ಸಲುವಾಗಿ, 'ಯೂರೋಪ್ನ ರೋಗ ತಡೆಗಟ್ಟುವಿಕೆ ಮತ್ತು ನಿಯಂತ್ರಣ ಕೇಂದ್ರ' ಹಾಗೂ 'ಅಮೆರಿಕಾದ ರೋಗ ತಡೆಗಟ್ಟುವಿಕೆ ಮತ್ತು ನಿಯಂತ್ರಣ ಕೇಂದ್ರ'ದ ಅಂತರರಾಷ್ಟ್ರೀಯ ತಜ್ಞರ ಗುಂಪೊಂದು, ಪ್ರತಿಜೀವಕ ನಿರೋಧಕ 'ಸೂಪರ್ ಬಗ್'ಗಳನ್ನು ಬಹು-ಔಷಧಿ ನಿರೋಧಕ (MDR), ವ್ಯಾಪಕ ಔಷಧಿ-ನಿರೋಧಕ (XDR) ಮತ್ತು ಪ್ಯಾನ್-ಔಷಧಿ ನಿರೋಧಕ (PDR) ಎಂಬ ಮೂರು ಗುಂಪುಗಳಾಗಿ ವಿಂಗಡಿಸಿದೆ. ಬಹು-ಔಷಧಿ ನಿರೋಧಕ 'ಸೂಪರ್ ಬಗ್'ಗಳು ಒಂದಕ್ಕಿಂತ ಹೆಚ್ಚು ವರ್ಗದ ಪ್ರತಿಜೀವಕಗಳಿಗೆ ನಿರೋಧಕವಾಗಿದ್ದು, ವ್ಯಾಪಕ ಔಷಧಿ-ನಿರೋಧಕ 'ಸೂಪರ್ ಬಗ್'ಗಳು ಹೆಚ್ಚಿನ ಸಂಖ್ಯೆಯ ಪ್ರತಿಜೀವಕಗಳಿಗೆ ನಿರೋಧಕವಾಗಿದ್ದು, ಎಲ್ಲಾ 'ಸೂಪರ್ ಬಗ್'ಗಳಲ್ಲಿ ಅತ್ಯಂತ ಮಾರಕವಾದ ಪ್ಯಾನ್-ಔಷಧಿ ನಿರೋಧಕ 'ಸೂಪರ್ ಬಗ್'ಗಳು, ಲಭ್ಯವಿರುವ ಎಲ್ಲಾ ಪ್ರತಿಜೀವಕಗಳಿಗೂ ನಿರೋಧಕವಾಗಿರುತ್ತವೆ.

'ಸೂಪರ್ ಬಗ್' ವಿರುದ್ಧ ಭಾರತದ ಯುದ್ಧ
ಭಾರತವು ವಿಶ್ವದ ಅತಿ ಹೆಚ್ಚು ಬ್ಯಾಕ್ಟೀರಿಯಾದ ಸೋಂಕುಗಳನ್ನು ಹೊಂದಿರುವ ದೇಶವಾಗಿದೆ. ಕ್ಷಯ, ಕಾಲರಾ, ಟೈಫಾಯಿಡ್, ನ್ಯುಮೋನಿಯಾ ಮತ್ತಿತರ ಸೋಂಕುಗಳು ಇಲ್ಲಿ ಹೆಚ್ಚು ಕಂಡುಬರುತ್ತವೆ. ವಾಸ್ತವವಾಗಿ, ವಿಶ್ವದಲ್ಲೇ ಅತ್ಯಧಿಕ ಸಂಖ್ಯೆಯಲ್ಲಿ ಕ್ಷಯರೋಗಿಗಳು ಇರುವ ತಾಣ ಭಾರತ. ಪ್ರಪಂಚದ ಎಲ್ಲಾ ಕ್ಷಯ ರೋಗಿಗಳಲ್ಲಿ ನಾಲ್ಕನೇ ಒಂದು ಭಾಗದಷ್ಟು ಜನ ಇಲ್ಲೇ ಇದ್ದಾರೆ ಎಂಬುದು ಕಹಿಸತ್ಯ. ಅದರಲ್ಲೂ ಇತ್ತೀಚಿಗೆ ಬಹು-ಔಷಧಿ ನಿರೋಧಕ ಮತ್ತು ವ್ಯಾಪಕ ಔಷಧಿ-ನಿರೋಧಕ ಕ್ಷಯರೋಗ ಪ್ರಕರಣಗಳು ಹೆಚ್ಚೆಚ್ಚು ವರದಿಯಾಗುತ್ತಿವೆ.

ಬಹು-ಔಷಧಿ ನಿರೋಧಕ ಮತ್ತು ವ್ಯಾಪಕ ಔಷಧಿ-ನಿರೋಧಕ ಕ್ಷಯರೋಗ ಪ್ರಕರಣಗಳಲ್ಲಿ, ಸಾಮಾನ್ಯ ಕ್ಷಯರೋಗ ಪ್ರಕರಣಗಳಿಗಿಂತಾ ಭಿನ್ನವಾಗಿ, ರೋಗನಿರ್ಣಯ ಪರೀಕ್ಷೆಗಳು ಮತ್ತು ಚಿಕಿತ್ಸೆಯನ್ನು ನಡೆಸಬೇಕಾಗುತ್ತದೆ. ಇಲ್ಲಿ, ವಿಶೇಷ ಮತ್ತು ಅಪರೂಪದ ಪ್ರತಿಜೀವಕಗಳ ಸಂಯೋಜನೆಯನ್ನು ಒಳಗೊಂಡಿರುವ ಚಿಕಿತ್ಸೆಯನ್ನು, ದೀರ್ಘಕಾಲದವರೆಗೆ ನೀಡಬೇಕಾಗುತ್ತದೆ. ಇದು ರೋಗನಿರ್ಣಯವನ್ನು ಕಷ್ಟಕರವನ್ನಾಗಿಸಿ, ಚಿಕಿತ್ಸೆಯನ್ನು ದುಬಾರಿಯಾಗಿಸುತ್ತದೆ. ಭಾರತದಲ್ಲಿ ಇನ್ನೂ ೨೨%ರಷ್ಟು ಜನರು ಬಡತನ ರೇಖೆಗಿಂತ ಕೆಳಗಿದ್ದು, ಚಿಕಿತ್ಸೆಗೆ ಹೆಚ್ಚಿದ ವೆಚ್ಚವು, ಸರಿಯಾದ ಚಿಕಿತ್ಸೆಯನ್ನು ಪಡೆಯುವ ಸಂಭವನೀಯತೆಯನ್ನು ಕಡಿಮೆಗೊಳಿಸುತ್ತದೆ; ಹಾಗಾಗಿ ಸೋಂಕಿಗೆ ಒಳಪಟ್ಟವರು, ಸೋಂಕಿನ ಸಮೇತ ಬದುಕಿ, ಬಲಿಯಾಗುತ್ತಾರೆ. ಕ್ಷಯರೋಗವು ವಾಯುಗಾಮಿ ಕಾಯಿಲೆಯಾಗಿರುವುದರಿಂದ, ಒಬ್ಬರಿಂದ ಅನೇಕ ಜನರಿಗೆ ಈ ಸೋಂಕು ಸುಲಭವಾಗಿ ಹರಡಬಹುದು ಮತ್ತು ಇದು ಅಪಾಯಕಾರಿ ಸಾಂಕ್ರಾಮಿಕಕ್ಕೆ ಕಾರಣವಾಗಬಹುದು. ಅದರಲ್ಲೂ ಬಹು-ಔಷಧಿ ನಿರೋಧಕ ಮತ್ತು ವ್ಯಾಪಕ ಔಷಧಿ-ನಿರೋಧಕ ಕ್ಷಯರೋಗ ಪ್ರಕರಣಗಳಲ್ಲಿ ಹೀಗಾದರೆ, ಗುಣಪಡಿಸಲಾಗದ ಕ್ಷಯರೋಗವು ಸಾಂಕ್ರಾಮಿಕ ರೋಗವಾಗಿ ಮಾರ್ಪಟ್ಟು, ಪ್ರಬಲ ಸಮಸ್ಯೆ ತಲೆದೋರುತ್ತದೆ.

ಕ್ಷಯರೋಗವು, 'ಸೂಪರ್ ಬಗ್'ಗಳ ದಾಳಿಗೊಳಗಾದ ಏಕೈಕ ಕಾಯಿಲೆಯಲ್ಲ. ಮತ್ತೊಂದು ಬ್ಯಾಕ್ಟೀರಿಯಾದ ಸೋಂಕಿನಿಂದ ಬರುವ ಕಾಯಿಲೆಯಾದ ನ್ಯುಮೋನಿಯಾ ಕೂಡ, ಈ ಪಟ್ಟಿಗೆ ಸೇರಿದೆ. ೨೦೧೭ರ ಅಧ್ಯಯನದ ಪ್ರಕಾರ, ೧೧ ರಾಜ್ಯಗಳಲ್ಲಿನ ಅನೇಕ ಆಸ್ಪತ್ರೆಗಳಲ್ಲಿ ನ್ಯುಮೋನಿಯಾದಿಂದ ಬಳಲುತ್ತಿರುವ ಮಕ್ಕಳ ರಕ್ತದ ಮಾದರಿಗಳಲ್ಲಿನ ಬ್ಯಾಕ್ಟೀರಿಯಾ 'ಎಸ್. ನ್ಯುಮೋನಿಯೆ', ಈಗಾಗಲೇ ಮೊದಲ-ಹಂತದ ಪ್ರತಿಜೀವಕ ನಿರೋಧಕಗಳಾಗಿವೆ. ಇವುಗಳಲ್ಲಿ ೬೬%ರಷ್ಟು ಬ್ಯಾಕ್ಟೀರಿಯ 'ಟ್ರೈಮೋಕ್ಸಸೋಲ್' ಪ್ರತಿಜೀವಕಕ್ಕೆ ನಿರೋಧಕವಾಗಿದ್ದು, ೩೭%ರಷ್ಟು 'ಎರಿಥ್ರೊಮೈಸಿನ್' ಮತ್ತು ೮%ರಷ್ಟು 'ಪೆನಿಸಿಲಿನ್'ಗೆ ನಿರೋಧಕವಾಗಿವೆ. ೨೦೧೭ರ ಮತ್ತೊಂದು ಅಧ್ಯಯನದ ಪ್ರಕಾರ, ಮತ್ತಷ್ಟು ತೀವ್ರವಾದ ನ್ಯುಮೋನಿಯಾವನ್ನು ಪರೀಕ್ಷಿಸಿದ ವೈದ್ಯರಿಗೆ ಕಂಡುಬಂದದ್ದೆಂದರೆ, ಅತೀ ಪ್ರಬಲವಾದ 'ಸೂಪರ್ ಬಗ್ 'ಕೆ. ನ್ಯುಮೋನಿಯಾ'ದ ಸೋಂಕಿಗೆ ಒಳಗಾದ ರೋಗಿಗಳಲ್ಲಿ ೬೯% ಜನ ಬದುಕುಳಿಯಲಿಲ್ಲ. ಈ 'ಸೂಪರ್ ಬಗ್'ಗಳು ಬಹು-ಔಷಧಿ ನಿರೋಧಕ ಬ್ಯಾಕ್ಟೀರಿಯಾವನ್ನು ನಿವಾರಿಸಲು ಬಳಸುವ 'ಕಾರ್ಬಪನೆಮ್' ಮತ್ತು ಯಾವುದೇ ಪ್ರತಿಜೀವಕವು ಕಾರ್ಯನಿರ್ವಹಿಸದಿದ್ದಾಗ ಬಳಸಲಾಗುವ ಕೊನೆಯ ಆಯ್ಕೆಯಾದ 'ಕೊಲಿಸ್ಟಿನ್' - ಈ ಎರಡೂ ಪ್ರತಿಜೀವಕಗಳಿಗೂ ನಿರೋಧಕವಾಗಿವೆ ಎಂದರೆ ಆಶ್ಚರ್ಯದ ಜೊತೆ ಆಘಾತವೂ ಖಂಡಿತ. ಟೈಫಾಯಿಡ್, ಕಾಲರಾ ಮತ್ತು ಗೊನೊರಿಯಾಗಳಂತಹ ಇತರ ಬ್ಯಾಕ್ಟೀರಿಯಾದ ಸೊಂಕುಗಳದ್ದೂ ಇದೇ ಕಥೆ.

ಸಂಕ್ಷಿಪ್ತವಾಗಿ ಹೇಳಬೇಕೆಂದರೆ, ಇದು ನಮ್ಮ ದೇಶವಷ್ಟೇ ಅಲ್ಲದೇ, ವಿಶ್ವವೇ ಎದುರಿಸುತ್ತಿರುವ ಪ್ರಮುಖ ಸಮಸ್ಯೆ. ಇದಕ್ಕೆ ಪರಿಹಾರ ಕಂಡುಕೊಳ್ಳಬೇಕಾಗಿರುವುದು ಈ ತಕ್ಷಣದ ಅನಿವಾರ್ಯತೆ. ಈ ಸಮಸ್ಯೆಯನ್ನು ನೀಗಿಸಲು ನಾವು ಯಾವ ಕಾರ್ಯಗಳನ್ನು ಕೈಗೊಳ್ಳಬೇಕು? ಈ ಬ್ಯಾಕ್ಟೀರಿಯಾದ ಸೋಂಕು ಹೆಚ್ಚಾಗಿ ಎಲ್ಲಿ ಕಂಡುಬರುತ್ತದೆ? ಇವುಗಳು ತಕ್ಷಣ ಉತ್ತರ ಬೇಡುವ ಪ್ರಶ್ನೆಗಳಾಗಿವೆ. ಆದಾಗ್ಯೂ, ಸಮಸ್ಯೆಗೆ ಉತ್ತರ ಕಂಡುಕೊಳ್ಳುವ ಮೊದಲ ಹಂತವು, ಪ್ರತಿಜೀವಕ-ನಿರೋಧಕ ಬ್ಯಾಕ್ಟೀರಿಯಾದ ಪರಿಣಾಮಗಳನ್ನು ಅರ್ಥಮಾಡಿಕೊಳ್ಳುವುದು ಮತ್ತು ಪ್ರತಿಜೀವಕಗಳ ತಡೆಯಿಲ್ಲದ ಬಳಕೆಯ ಬಗ್ಗೆ ಜಾಗೃತಿ ಮೂಡಿಸುವುದೇ ಆಗಿದೆ.

Section: General, Science, Health, Deep-dive Source:
Leh-Ladakh Wednesday, 30 May, 2018 - 12:47

Researchers from Defence Institute of High Altitude Research (DIHAR), Leh-Ladakh and Defence Institute of Physiology and Applied Sciences (DIPAS), New Delhi, under Defence Research and Development Organization (DRDO), are studying the benefits of Hippophae rhamnoides, generally known as common sea buckthorn, in improving the health of chicken reared in high altitude cold deserts. The study shows a reduction in mortality rates in chicken that were fed extracts from the fruit of sea buckthorn plant.

Extreme climate conditions, like cold mountainous regions can pose numerous challenges to life. From the reduced oxygen levels to extreme variations in temperatures, life has to evolve to survive such harsh conditions. When life forms from elsewhere are brought into such extreme climate, they often show a drastic increase in mortality rates. Broiler chicken reared in the cold desert of Himalayas, 3500 meters above sea level (MSL), also face such harsh conditions.

“Extremes of climate and hypobaric hypoxia cause poor growth performance in broiler chickens at high altitude” say the authors.  Hypobaric hypoxia (medical condition caused by decreased oxygen in the atmosphere), excessive Ultraviolet radiations, very less availability of water vapours in the atmosphere and shortage of animal food are some of the reasons for the poor performance.

To overcome the difficulties, researchers turned to ‘Amchi’ system of medicine—a traditional system of medicine practiced mainly in Tibet, Magnolia, Bhutan, some parts of China, Nepal, and trans-Himalayan regions of India. The system makes use of the widely abundant plant species to treat ailments. For their study, the researchers used extracts from the fruit of Hippophae rhamnoides or common sea buckthorn—a temperate shrub growing at altitudes of 3000m to 4500m above MSL. Previous studies reported various pharmacological activities of the plant including antioxidant, immunomodulatory, anti-stress, anti-tumor, hepato protective, and radio protective.  For this study, researchers used fresh fruits of the plant, obtained from a local market in Leh, for extraction.

Rhode Island Red cross-bred broiler chickens obtained from the region were used for the study. The chicken were split into groups, with a control group that received no additives in their food, and groups T1 through T6, which received different doses (100, 150, 200, 300, 400 and 800 mg/kg body weight of the chicken) of seabuckthorn extracts along with their regular feed.

The study showed an increase in phytomolecules (molecules of plant origin) in the chickens that were fed the plant extract. Researchers also observed modification in the immune response by the extracts in chicken lymphocytes. Further, 200 mg/kg body weight of chicken was found to be ideal dose of the additive for healthier individuals.

According to the researchers “treatment group birds had shown better physio-biochemical indices as compared to control group birds. Interestingly, lower mortality rate due to ascites and coccidiosis was recorded in treatment groups and therefore, higher net return was observed.

Section: General, Science, News Source:
Bengaluru Wednesday, 30 May, 2018 - 08:01

The flood on 1st December 2015 in Chennai brought the fourth most populous city in India to a standstill. The incessant rains caused economic damages amounting to $3 billion, and at least 250 people lost their lives. The El-Nino climatic cycle impacted the 2015 northeast monsoons during October-December. The areas at the Coromandel coast were the worst affected by flooding. While the role of climate change in that floods is still debated, what role did the geography of the city play? Understanding this will help in forecasting such events in future.

A new study by a researcher at the Indian Institute of Science, Bengaluru, has explored the role of the Eastern Ghats, located at a distance of 200 km from Chennai, in the devastating floods of 2015.

Chennai receives most of the rains from the northeast monsoon, when cyclonic systems, also known as ‘depressions’, form over Bay of Bengal and make landfall over the southern east coast of India. During 2015, the city saw three 'heavy rainfall' periods; the first lasting from 7th–9th November, the second from 14th–16th November, and the third from 30th November–2nd December. On 1st December, the city witnessed as much as 494 mm of rain in less than 24 hours, the odds of this occurring are once in at least 100 years.

Although computer models forecast rainfall, analysis of weather conditions which lead to such unforeseen event is necessary to trust and further improve these models. In this study, the researcher points out that the raining clouds were stationary over Chennai on 1st December 2015. The study also proposes a mechanism by which clouds can be blocked by the Eastern Ghats remotely over the coast. The study also proposes a mechanism by which clouds can become stationary over the coast involving interaction between clouds, mountain and wind.

“When it rains, the raindrops evaporate, cooling the air in that region. This chunk of cold air over the surface is known as the 'cold pool'. It takes more energy to lift the denser cold pool over the mountains. At certain speeds, the winds lack the energy to carry the cold pool over the mountains, but have enough to hold them against the mountain”, explains Mr. Jayesh Phadtare, a research scholar from IISc and the author of the study reported in Monthly Weather Review published by the American Meteorological Society.

Detailing the turn of events on the fateful day of 1st December, Mr. Phadtare says, “When the energy of the winds is almost equal to that required to climb a mountain, the cold pool becomes stationary, and its edge can extend about hundreds of kilometres ahead of the mountain. The warmer, and hence lighter, oceanic winds get uplifted well ahead of the mountain by the cold pool.  Thus, the winds get blocked even before they reach the mountain walls by the invisible walls of the cold pool. This ‘upwind blocking' (upwind to the mountain) of winds occurred on 1 December 2015 over Chennai.”

The study used the Weather Research and Forecasting (WRF) model, developed by National Center for Atmospheric Research (NCAR), USA, that solves mathematical equations for weather forecasting. It is used by weather agencies all over the world, including the India Meteorological Department (IMD). The researcher validated the mechanism in the model with two experiments – the absence of orography and no evaporative cooling of rain. In both cases, clouds were not stationary over Chennai, implying that the Eastern Ghats obstructed the cold pool from moving downstream, thus stagnating the clouds. Continuous catastrophic rainfall that followed drowned Chennai.

The study is not the first to show that mountain features affect precipitation. “There are studies done over the California coast, over the west coast of Taiwan, and even over our Western Ghats where mountains influence the coastal rainfall”, says Mr. Phadtare. “But each region is unique with its own geographical settings, the weather patterns that develop are also different. Although one can draw some analogies, rules that apply over one region may not be valid over the other. However, the Eastern Ghats is a more complex mechanism and was not yet identified. In that sense, this modelling study is unique” he adds, talking about the implications of this study.

Cities and municipalities indeed have a significant role to play in ensuring floods and similar disasters are managed well by clearing clogged stormwater drains and cracking down illegal encroachment of water bodies. However, studies like this will improve our forecast of extreme rainfall and help to step up disaster preparedness and better management strategies.

The work was supported by the high performance computer (HPC) system facility at CAOS, IISc, funded by the Department of Science and Technology under Fund for Improvement of Science and Technology Infrastructure in Universities and Higher Educational Institutions (FIST) scheme and Divecha Center for Climate Change (DCCC).

Section: General, Science, Deep-dive Source:
Bengaluru Monday, 28 May, 2018 - 21:35

Researchers at Raman Research Institute, Bengaluru, are exploring the properties of single walled carbon nanotube (CNT) immersed in aqueous triblock copolymer solution. The newly formed CNT-polymer hybrid could replace the use of carbon nanotubes by itself, thanks to its remarkable mechanical, thermal and electrical properties.

Carbon nanotubes (CNT) are cylindrical tubes made by rolling up a single sheet of carbon atoms called graphene, and with a diameter of only a few nanometers. They are the strongest and stiffest material discovered yet, and also perform remarkably as a thermal and electrical conductor, with very little resistance. This has made CNT a much sought-after material in engineering and material designing. However, when immersed in water or a solution, due to their hydrophobic (repel water) nature, they clump together in the solution. This clumping together compromises some of the beneficial properties of the material, as bulk CNT is not as strong as individual tubes. Scientists overcome the limitation by chemical and physical modifications of the nanotubes.

In the new research, scientists wanted to study one such chemical modification of the carbon nanotubes, by immersing them in polymers—by immersing them in an aqueous solution of triblock copolymer. Copolymers are large molecules formed by joining repeating subunits of monomer molecules. A triblock polymer is made of repeating monomers that can be divided into three unique parts of the constitutional units. Strands of CNT were immersed in an aqueous solution of a triblock copolymer. Once immersed, “the single-walled carbon nanotubes in this system aggregate to form bundles, and the bundles aggregate to form net-like structures” explain the authors.

The CNT-polymer hybrid was then subject to different tests, including scanning electron microscopy (SEM), differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), electrical conductivity, and H NMR studies, at different temperatures.

The studies reveal the formation of three distinct self-assembled CNT-polymer hybrids, depending on the temperature and phases of the polymer. “We find CNT-unimer (a type of polymer belonging to a certain group) hybrid at low temperatures, CNT-micelle (colloidal solution) hybrid at intermediate temperatures wherein the polymer micelles are adsorbed in the pores of the CNT nets, and another type of CNT-micelle hybrid at high temperatures wherein the polymer micelles are adsorbed on the surface of the CNT bundles” reveal the authors about the results. Interestingly, the researchers also noted the formation of cone-shaped and cube shaped formation of the polymer micelles adsorbed on the CNT nets, at different temperatures. The researchers further went on to study the properties of the three hybrids.

By studying the properties of the hybrid material, the study opens up further ways to enhance the already remarkable properties of CNTs, and could also reveal new and interesting features of the hybrid material, in the future.

Section: General, Science, Technology, News Source:
Bengaluru Monday, 28 May, 2018 - 14:07

Dr Kamaljit Bawa, President, Ashoka Trust for Research in Ecology and the Environment (ATREE) and Distinguished Professor of Biology at the University of Massachusetts, Boston, has been awarded the Linnean Medal in Botany by the Linnean Society of London at its annual meeting.

The Society has been awarding the Linnean Medal every year since 1888. Dr Kamaljit Bawa is the first Indian to receive the medal in its 140-year old history. The recognition, according to society’s website is awarded as “as an expression of the Society's esteem and appreciation for service to science”.

Dr Bawa was recognised for his pioneering research on the evolution of tropical plants, tropical deforestation, non-timber forest products, and for decades of work on the biodiversity of forests in Central America, the Western Ghats and the Eastern Himalaya. Also cited were Dr Bawa’s efforts to establish a world-class environmental centre, ATREE, in Bengaluru, the journal Conservation and Society and the India Biodiversity Portal.

“The Linnean Medal is a good recognition of our work on conservation and sustainability, and will serve as a fresh reminder that we need to redouble our efforts to fully document and study our planet’s incredible plant wealth that is rapidly declining,” said Dr Bawa in a press release.

Incidentally, the first scientist to receive the Linnean Medal, in 1888, was Sir Joseph D. Hooker, who compiled the monumental seven-volume Flora of British India—the first comprehensive account of India’s plants.

The Linnean Society, named after the famous Swedish biologist Carl Linnaeus, who gave us a system of naming plants and animals, was established in 1788 and is among the oldest academic societies of the world.

(Based on a press release from ATREE).

Section: General, Science, Ecology, News Source:
Bhopal Sunday, 27 May, 2018 - 19:17

Every passing day we are exposed to a cocktail of chemicals through medicines, cosmetics, pesticides, aerosols, gaseous emissions, pollens, etc. Many of these affect our health; some are allergens, while others could be carcinogens or cause fatal diseases. Although some products are tested to ascertain their safety for human use, the process is tedious, time-consuming and involve testing on animals. In a study, researchers from the Indian Institute of Science Education and Research (IISER), Bhopal, have developed an alternative approach to test the toxicity of small molecules by using their chemical and physical properties.

The researchers of the study, published in the journal Frontiers in Pharmacology, have developed a web-based tool called ToxiM. It uses machine learning and informatics to predict the toxicity of a compound using its structural and molecular properties, and its solubility and permeability which affect its absorption within the cells, and hence its toxicity. The researchers believe that the tool would be handy to the scientific community to study the environmental and physiological toxicity of a molecule.

ToxiM works by studying specific features of various compounds, their molecular descriptors and fingerprints. Molecular descriptors of a compound depict the two and three-dimensional characteristics of a molecule in numerical value. Fingerprints are used to understand chemical and structural properties of the molecule, which help to assess the solubility of a molecule. In this study, the researchers focused on examining the permeability of various compounds on our epithelial cells to determine their toxicity.

The researchers trained their tool by feeding it with data of 2,849 previously studied toxins, which have been medically recorded as ‘toxic’ even in low concentrations. They also supplied data of human metabolites that are produced in our body and are non-toxic to us. They also provided data of 41 commercially banned drugs determined to be toxic and 15 compounds commonly found in beauty products, detergents and used as food additives and preservatives. Using these datasets, they constructed three training models and performed statistical analysis to determine relationships among them.

The researchers tested ToxiM by feeding it with a validation dataset where the toxicity values predicted by the tool were verified against their known or previously reported values. The results show that the tool predicted accurately for almost all the compounds except for a few discrepancies. It classified common chemicals such as food additives like aspartame and saccharin used in sweeteners, pesticides like EDTA (Ethylenediaminetetraacetic acid) and DCPA (Dimethyl tetrachloroterephthalate) and few chemicals used in beauty products as toxic. Some compounds, whose uses are debatable, such as imidazolidinyl urea used in cosmetics and sodium hypochlorite or bleaching powder, produced mixed results through different models in ToxiM.

Talking about the precision of ToxiM, the researchers mention, “the reported accuracies in assigning a molecule as toxic or non-toxic, and the values that predict the aqueous solubility and permeability attest the performance of the tool. The models developed for ToxiM also produced a higher performance compared to some other online tools”.

ToxiM is a tool intended to be used by scientists, especially those studying toxic molecules. The platform is user-friendly, and a tutorial for navigation through the website is also available. The user is required to submit a query molecule through a Spatial Data File (SDF) or a similar format and may select one of the optimised models for prediction. The authors suggest that “the user should examine the query molecule using all the models available at the web server for comprehensive results”. In the future, the applicability of the tool may be improved by including other properties such as compositional, concentration, target organism and system, and any other factor that leads to physiological toxicity.

Section: General, Science, News Source:
Bengaluru Friday, 25 May, 2018 - 10:29

A team of researchers from Indian Institute of Science (IISc), Bengaluru, Max Planck Institute for Intelligent Systems, Stuttgart, Germany, and University of Stuttgart, Stuttgart, Germany have developed a novel silver nanoparticle-graphene hybrid photodetector device with an increased ability to detect Ultraviolet light.

Graphene—a form of carbon made of a single sheet of graphite or carbon atoms arranged in a hexagonal pattern, has been a much studied material, ever since its rediscovery in 2004. Thanks to the advantageous electrical and physical properties of this 2 dimensional material, researchers have been able to exploit these properties to advance the electronics and materials industries. One area where graphene has been found wanting is in its interaction with photons-particles of light.

To enhance this property of interaction with light, researchers have proposed several strategies. One of these strategies has been to sensitize the grapheme with plasmonic nanostructures, to form a graphene-plasmonic hybrid system. Plasmonic nanoparticles are particles which show an increased interaction with light of wavelength larger than the particle itself. These particles are said to interact with light waves through an oscillation of their internal electric fields, as the light hits the particle. Previous studies have demonstrated enhanced visible and infrared light detection efficiency in graphene-plasmonics hybrid materials. However, these devices haven’t been efficient at detecting ultraviolet (UV) light.

In their new study, the researchers wanted to develop a graphene-plasmonics hybrid material with enhanced UV light detection abilities. For the study, silver nanoparticles were chosen as the plasmonics particles, which were decorated with graphene, to form the hybrid structure.

The researchers employed self-assembly and physical shadow growth techniques to “fabricate a regular large-area array of silver nanoparticles, each measuring around 50 nanometers. Onto this array, grapheme is deposited using chemical vapour deposition technique, where graphene vapour is incident on the nanoparticles to form a layer of graphene on them. “The device fabrication strategy is scalable and modular” remark the authors, making it easier to commercialize the process.

The new silver nanoparticle-graphene hybrid device showed an enhanced ability to interact with light of wavelength ranging between 330 nanometers to 450 nanometers. Further, when lower wavelengths of light were used, the researchers measured an even higher responsivity from the hybrid device corresponding to a staggering 10000 times increase over the responsivity of native graphene. If commercialized, the material could greatly increase our ability to detect ambient UV light.

Section: General, Science, Technology, News Source:
Mumbai Thursday, 24 May, 2018 - 20:50

There exists a theory among economists called the ‘pollution haven hypothesis’ that talks about how foreign investments are related to environmental regulations. It states that companies from developed countries often seek to set up manufacturing units in developing countries not only because they can obtain cheap labour and resources, but also because environmental regulations in these countries are usually lenient, reducing the cost of compliance.  But does empirical data support this hypothesis? In a new study, researchers from the Indian Institute of Technology Bombay (IIT Bombay) explored this question in the Indian context and found that the data suggests otherwise.

In the study, published in the journal Asian Development Review, the researchers note that factors like infrastructure and access to market influence foreign investments more than environmental norms.  In other words, the 'pollution haven hypothesis' fails to explain the investment patterns in the Indian context.

Foreign direct investments (FDI) into India have been significantly increasing in the recent years, especially after the liberalisation era of the early 1990s. For governments, these investments are significant to generate jobs and showcase development.  Hence, if the 'pollution haven' hypothesis is, in fact, correct, governments would then have to reduce environmental standards to attract more investments. Although there are pieces of evidence where the governments have relaxed environmental norms, this is not the case everywhere, say the researchers.

"In the People’s Republic of China, provinces compete intensely for foreign capital by offering promises of preferential treatment to potential foreign investors, which can include a tacit (or explicit) commitment to lax enforcement of environmental standards”, the researchers say, giving an example where the hypothesis holds true. However, there are cases where environmental standards were made stringent to attract foreign investments. "Foreign investors in Costa Rican banana production have insisted upon the application of high environmental standards as their European customers demand an environmentally sound product”, is an example the researchers quote of the latter case.

But, what about India? In this study, the researchers test the 'pollution haven' hypothesis for 21 Indian states and union territories from 2002-2010 by examining the impacts of environmental governance on FDI over the years.  One way to calculate the cost of compliance with environmental regulations is to add all the pollution control costs by various companies, for each state.  Although this approach is used in many previous studies, it is flawed because, if a state has many pollution-intensive units, then the pollution control cost is naturally higher even though the environmental governance in that state may not necessarily be stringent, points out the study. Therefore, it has considered the reworked metric that addresses the flaws of previous metrics, and is a more effective reflection of the level of environmental governance in a particular region.

The results revealed that states and union territories like Chandigarh, Odisha, and Karnataka have the highest environmental stringency whereas Bihar, Delhi, North Eastern states and the Andaman and Nicobar Islands exhibit the lowest.  Also, Andhra Pradesh, Punjab, Rajasthan, Odisha, Goa, and Haryana have become stringent over time, whereas Assam, Chhattisgarh, Gujarat, Delhi, Uttar Pradesh, and Uttarakhand have become lenient over time.  However, this stringency in environmental governance, evident from the cost of compliance, was found to have no impact at all on the FDI.  This finding empirically demonstrates that a region’s environmental norms do not influence the investment decisions of the foreign companies.

Apart from environmental governance, the study also considered various other factors that influence FDI in a state. It found that factors like market size and demand, the share of the manufacturing sector in the state economy, availability of power, proximity to the coast, existing investment stock, availability of resources and human capital influence FDI decisions.  It also found that higher per capita income of a region attracts more investments as it demonstrates a higher purchasing power of the people and hence, an excellent market opportunity.

The study is a right step towards demystifying the theory of ‘race to the bottom’ by relaxing all environmental regulations in the name of attracting investments, as it drains resource availability and health of the citizens.  It further notes that “foreign firms generally seek consistent environmental enforcement over lax enforcement, which may also hold true in the case of Indian states.”

So, the message is clear—the way to attract investments is not by relaxing the environmental standards, but by providing better infrastructure and market access.

Section: General, Science, Society, Policy, News Source:
Mumbai Thursday, 24 May, 2018 - 11:08

Researchers at Indian Institute of Technology Bombay (IITB), Mumbai, have developed a new minimum opportunity cost targeting algorithm (MOCTA) to help organizations and institutions select the right environmental and conservation projects to pursue.

Researchers working in institutions and organizations are often inundated with project ideas to pursue. Corporations are often obliged to carry out environmental and conservation projects, as part of their corporate social responsibilities, while many NGOs and institutions also pursue such initiatives out of self-interest. Funding agencies that fund these projects, however, must be able to select the right projects to pursue based on several criteria, like benefits, applications, and overall cost of the project. One of the main factors that helps in deciding the right project to pursue is capital budgeting—the amount of money to be allocated for the project.

“To achieve the market competitiveness as well as sustainable products and processes, a firm invests in different environmental and conservation projects. Capital budgeting essentially entails the decision of funding a set of acceptable projects from a larger pool of available projects, subject to different funding constraints” remark the researchers.

To help with this process of selecting the right project to pursue, researchers at IITB have developed the novel minimum opportunity cost targeting algorithm (MOCTA). The algorithm helps to address the capital budgeting problems for selecting environmental management problems. MOCTA is based on the principles of Pinch Analysis—a sequential methodology used to minimize energy consumption in chemical processes by optimization of the systems involved. Here, partially acceptable problems are formulated as linear programming- a mathematical optimization technique. The algorithm was also used, in coordination with another technique called branch and bound, to solve problems where a project is either completely accepted or completely rejected.

The researchers went on to demonstrate the applicability of the methodology through a complex search tree, using a hypothetical example. They further demonstrated the validity of the algorithm “through case studies of selecting energy conservation projects in the Indian Paper and Pulp industry”.

MOCTA could help optimize the process of selecting the right environmental and conservation projects for organizations and institutions to pursue, by reducing the amount of time, man-hours and other resources spent in taking the decision.

Section: General, Science, Technology, News Source:

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