20 April Current Affairs
April 20, 2020
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April 22, 2020
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21 April Current Affairs

Portable Sensor for Heavy Metal Detection in Water

In News:

Recently, the Centre for Nano and Soft Matter Sciences (CeNS) has developed a compact solid-state sensor to detect the heavy metal ions in water.

It is a portable device which can help onsite detection in remote areas.

Key Points :-

The compact solid-state sensor can detect the heavy metal ions like lead ions (Pb2+) down to 0.4 parts per billion (ppb).


A sensor film was prepared by forming a composite  between manganese doped zinc sulfide quantum dots and reduced graphene oxide on a glass substrate.

These particular quantum dots are water-soluble and have high photoluminescence (~30%) quantum yield, making them suitable for luminescence-based sensing.

Luminescence is emission of light by certain materials when they are relatively cool. It may be seen in neon and fluorescent lamps.

These quantum dots can be excited with handheld UV (ultra-violet) light of 254 nm, thus making them portable even to remote areas.

Excitation, in physics, refers to the addition of a discrete amount of energy (called excitation energy) to a system—such as an atom, or a molecule—that results in its alteration, ordinarily from the condition of lowest energy (ground state) to one of higher energy (excited state).

If a drop of water containing heavy metal ions such as mercury (Hg), lead (Pb), cadmium (Cd), etc. are added to the composite film, the emission of the film extinguishes within seconds.

The development of efficient and portable sensors for rapid onsite detection of heavy metal ions becomes important due to the health hazards associated with them.

Heavy metal ions pose severe potential threats to living beings (kidney damage, bone fractures, etc.).

They can be accumulated in the body easily and cannot be detoxified by any chemical or biological processes.

This study demonstrates the easy detection of heavy metal ions in water. However,  strategies are being developed to improve the selectivity of the detection.

Chitra GeneLAMP-N for Covid-19 Test

In News:

Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Trivandrum (Kerala), has developed a diagnostic test kit that can confirm Covid-19 in 2 hours at low cost.

SCTIMST is an Institute of National Importance under the Department of Science and Technology (DST).

Key Points:

The test kit, funded by the DST called Chitra GeneLAMP-N, is highly specific for SARS-CoV-2 N-gene and can detect two regions of the gene.

This would ensure that the test does not fail even if one region of the viral gene undergoes mutation during its current spread.

It is a confirmatory diagnostic test, which detects the N Gene of SARS- COV2 using reverse transcriptase loop-mediated amplification of viral nucleic acid (RT-LAMP).

The results can be read from the machine from the change in fluorescence.

Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation.

The tests performed at National Institute of Virology (NIV), Alappuzha (Kerala) (authorized by Indian Council of Medical Research (ICMR)) show that Chitra GeneLAMP- N has 100% accuracy and match with test results using Reverse Transcription Polymerase Chain Reaction (RT-PCR).

This has been intimated to Indian Council of Medical Research (ICMR), the authority to approve it, for Covid-19 testing in India, following which License needs to be obtained from Central Drugs Standard Control Organisation (CDSCO) for manufacture.


A total of 30 samples can be tested in a single batch in a single machine allowing a large number of samples to be tested each day.

Current Polymerase Chain Reaction (PCR) kits in India enable detection of E gene for screening and RdRp gene for confirmation. Chitra GeneLAMP-N gene testing will allow confirmation in one test without the need for a screening test and at much lower costs (less than Rs. 1000/test).

Chitra GeneLAMP-N makes confirmatory tests results of Covid-19 possible in 2 hours.

The detection time is 10 minutes, and the sample to result time (from RNA extraction in swab to RT-LAMP detection time) will be less than 2 hours.

The testing facility can be easily set up even in the laboratories of district hospitals with limited facilities and trained laboratory technicians.

Inactivated Virus Vaccine in Focus for Covid-19

In News:

Recently, researchers from the Centre for Cellular and Molecular Biology (CCMB) have started developing an inactivated virus vaccine for the novel coronavirus (SARS-CoV-2).

Key Points:

Vaccination is thought to be the most effective and sure way to arrest the progress and deadly effect of the virus.

Inactivated vaccines are known for their safety and easy production.

Inactivated Vaccines:

Active pathogens are grown in large numbers and then killed either by a chemical or heat. Although the pathogen is killed, or made to lose its reproduction capacity, various parts of the pathogen are intact. E.g The antigen (the chemical structure) that is recognised by the immune system is left unimpaired.

When this dead microbe is introduced in the body, the immune system is tricked to respond by producing antibodies against specific antigens still left intact, without knowing that the pathogen is defective.

As the pathogen is dead, it cannot reproduce nor cause even a mild disease. Thus, it is safe to administer to even people with lesser immunity, like the old and those who have comorbidity.

Inactivated polio vaccine and the rabies vaccine are made this way.

Benefit: If a large amount of coronavirus is grown and inactivated, that will be material for candidate vaccines to be injected.

Challenges: The important technological challenge is growing the coronavirus outside of the human host.

As the novel coronavirus has evolved to life on human cells, locating the right source of the cell line to grow the virus outside of the human body is key to this technology.

CCMB is using the epithelial cell line from African green monkeys to artificially grow and harvest the deadly virus.

The cells will be observed and if the cells show changes, including dying of cells and release of the virus, then the culture is positive.

Finding a right cell growing technology for the novel coronavirus will also help in drug development.

Seismic Noise

In News:

Scientists at the British Geological Survey (BGS) have reported a change in the Earth’s seismic noise and vibrations amid the coronavirus lockdown.

These findings have come two weeks after seismologists at the Royal Observatory in Belgium observed a 30-50% fall in levels of seismic noise since schools and businesses were closed in mid-March.

Key Points:

  1. a) Seismic noise

In geology (study of rocks), seismic noise refers to the relatively persistent vibration of the ground due to a multitude of causes.

This noise includes vibrations caused due to human activity, such as transport and manufacturing.

Scientists first observed this seismic noise — everything recorded on seismograms that cannot be attributed to earthquakes — at the end of the 19th century.

It is the unwanted component of signals recorded by a seismometer and makes it difficult for scientists to study seismic data that is more valuable.

Apart from geology, seismic noise is also studied in other fields such as oil exploration, hydrology, and earthquake engineering.

  1. b) Benefits of reduction in seismic noise

Usually, to measure seismic activity accurately and reduce the effect of seismic noise, geologists place their detectors 100 metres below the Earth’s surface.

Because, the seismic noise vibrations caused by human activity are of high frequency (between 1-100 Hz), and travel through the Earth’s surface layers.

However, since the lockdown, researchers have said that they were able to study natural vibrations even from surface readings, owing to lesser seismic noise.

Due to lower noise levels, scientists are now hoping that they would be able to detect smaller earthquakes and tremors that had slipped past their instruments so far.

New FDI Rule

In News:

The Government of India has made its approval for Foreign Direct Investment (FDI) by neighbouring countries mandatory.


This revised FDI policy aims to curb opportunistic takeovers/acquisitions of Indian companies due to the current Covid-19 pandemic.

Key Points:

FDI in India: FDI is allowed under two modes – either through the automatic route, for which companies don’t need government approval, or through the government route, for which companies need a go-ahead from the centre.

  1. a) According to the new FDI policy:

An entity of a country, which shares a land border with India or where the beneficial owner of an investment into India is situated in or is a citizen of any such country, can invest only under the Government route.

A transfer of ownership in an FDI deal that benefits any country that shares a border with India will also need government approval.

India shares land borders with Pakistan, Afghanistan, China, Nepal, Bhutan, Bangladesh and Myanmar.

Investors from countries not covered by the new policy only have to inform the RBI after a transaction rather than asking for prior permission from the relevant government department.

  1. b) Impact

The earlier FDI policy was limited to allowing only Bangladesh and Pakistan via the government route in all sectors. The revised rule has now brought companies from China under the government route filter.

China’s footprint in the Indian business space has been expanding rapidly, especially since 2014.

  1. c) Chinese investment in India

The net Chinese investment in India, which was $1.6 billion in 2014, shot up five-folds to at least $8 billion (Rs 60,800 crore) in the next three years — with a noticeable shift from state-driven to market-driven investment from the Chinese private sector.

Official figures underestimate the amount of investment: They neither account for all Chinese companies’ acquisitions of stakes in the technology sector nor investments from China routed through third-party countries, such as Singapore.

For instance, a $ 504-million investment from the Singapore arm of the mobile firm Xiaomi would not figure in official statistics because of how investments are measured.

It has been seen that the Chinese firms have escaped the kind of scrutiny in India that their investments have attracted in the West despite several high-profile investments and acquisitions.

Another concern is that there is no clear separation between the Chinese state and private business. They work closely in pursuing many goals.