Science and Technology Current Affairs

Two new species of Cycas discovered

Research conducted on Cycas pschannae, a lone tree found in the Acharya Jagadish Chandra Bose Indian Botanic Garden, West Bengal has revealed two new species of Cycas to the world. This discovery takes the total number of Cycas species found in India to 14.

Cycas

Cycas are one of the most ancient plants whose fossils date to the Jurassic period. They are often referred to as living fossils. They have evolved on the earth as the first seeded plants and they grow very slowly, adding only a few centimetres every year. Nearly 65% of Cycas are threatened. There are over 100 species of Cycas found across the globe.

Key Facts

Initial studies on the lone Cycas pschannae tree revealed that it was Cycas, a gymnosperm. Further research based on its anatomical and morphological characters led to the discovery of new species of Cycas pschannae and later Cycas dharmrajii in the Andaman and Nicobar Islands.

Cycas dharmrajii is characterised by the abnormal branching habit of its giant trunk and its swollen base. It has well-defined 10 to 28 hook-like structures in the apex of the mega sporophyll which makes it distinct from other Cycas found in the country. Sporophylls are spore-bearing leaf-like female sex organ of the plant. The sporophylls of Cycas pschannae are characterised by the presence of two lateral horn-like structures.

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IISc researchers develop low-cost, sensitive CO sensor

Indian Institute of Science (IISc) researchers from Bengaluru have developed a highly sensitive, low cost nanometre-scale carbon monoxide (CO) sensor, with potential applications in environmental pollution monitoring.

The sensor was developed using novel fabrication technique that does not involve costly and time consuming lithography technology.

Carbon Monoxide (CO)

CO is a colorless, odorless gas. It is harmful when inhaled in large amounts The greatest source of CO is internal combustions (IC) engines of cars, trucks and other vehicles or machinery that burn fossil fuels. Breathing high concentration of CO reduces the amount of oxygen that can be transported in the blood stream to critical organs like the heart and brain.

Key Facts

The nanometer-sized sensor was made using zinc-oxide (ZnO) nanostructure on a silicon wafer substrate. Tiny polystyrene beads were also used on the wafer. These beads were first added on the on the oxidised silicon wafer arrange themselves into what is called a hexagonal close-packed structure.

Reasonable level of vacuum is maintained between the wafer and beads. When a high voltage is applied, it etches away the surfaces of the beads until a gap of desired thickness is formed between adjacent beads. Then ZnO is deposited on the system. This occupies the spaces between the beads, forming a honeycomb like nano-mesh that can function as a nanosenor.

Significance

The nanometre-scale CO sensor is able to detect a difference in CO level as low as 500 parts per billion (ppb). It can selectively respond to CO even in the presence of other gases. It also significantly cuts down the time and cost involved in making nanostructured gas sensors.

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