From the lab: Superconducting at higher temperatures; a material passes laboratory test

One of the constraints we face in transportation of electricity is the resistance of materials, such as the wires, that carry the current. Most materials offer some kind of resistance because of which transmission losses in electricity take place, the energy getting dissipated in the form of heat. This resistance is quite useful in certain circumstances, especially in situations where the flow of electrical current needs to be regulated and controlled.

However, in certain situations we like this resistance to be as low as possible. It is possible to have very low resistance, even zero resistance, in some materials in certain special conditions. These materials are called superconductors, but they exhibit this property only at very low temperatures, typically below -200°C. Coils made of superconducting wires can withstand very high current and produce high magnetic fields that are used in MRI imaging. One of the objectives in superconductivity research has been to induce superconductivity in materials at higher temperatures, preferably at room temperature, so that they can be used for everyday applications such as transporting electricity through overhead wires without any transmission losses and more energy-saving electronic devices can be realised.

Generally, elementary particles, depending on their quantum behaviour, are distinguished in two broad classes — the bosons named after Indian physicist Satyendra Nath Bose, and fermions named after Italian scientist Enrico Fermi. For example, recently discovered “Higg’s particles” are bosons while electrons are fermions.

Electrons are described by a theory developed by English scientist Paul Diarc, who combined quantum theory with Einstein’s special theory of relativity, and consequently the electrons can be further classified as Dirac fermions. An extension of this theory predicts the existence of other special classes of fermions, such as the Weyl fermions named after the German mathematician and physicist Hermann Weyl who proposed their existence in 1929.

The Weyl fermions are mass-less particles but they are expected to be real. Weyl fermions were initially expected to be observed in cosmic radiations but that has never happened. Instead, a couple of years ago, they were observed to exist as quasi-particles, collective excitations of electrons, in a semi-metal tantalum arsenide (a compound of tantalum and arsenic) which is now also referred to as a Weyl semi-metal.

Our earlier work had shown that in a different kind of very complex materials, so-called topological Dirac semi-metals, we were able to induce superconductivity in special situations. After the discovery of Weyl semi-metals, we were interested in studying whether the Weyl fermions also have any bearing on superconductivity.

Our recent research at IISER has shown that this indeed is a case. Weyl fermions in tantalum arsenide can not only take part in superconductivity but also do so in a more conventional manner and at relatively high temperatures under certain controllable conditions. So Weyl semi-metals offer a much better possibility of realising superconductivity at higher temperatures. This result can have important consequences for research aimed at obtaining superconductivity at normal temperatures and used for everyday purposes such as electricity transmission without appreciable losses.

But there are more immediate exciting implications. The superconducting phases realised on Weyl semi-metals, in presence of a magnetic field, might also host another type of elusive particles called the Majorana fermions, initially predicted by Italian scientist Ettore Majorana in 1937. One of the major obstacles in quantum computing, the new-age computing that involves quantum data bits (called “qubits”) for processing and storing information, are fragile and easily perturbed by disorders or impurities in a material. The Majorana fermions are known to be “fault tolerant” — they are almost insensitive to disorder. Thus, it is possible to use them in fault-tolerant quantum computing.

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Year after assurance, govt yet to move on request to ban 37 ‘harmful drugs’

The drugs could be injected into the middle ear, from which they would diffuse across a membrane into the inner ear. )Source: Thinkstock Images) The drugs could be injected into the middle ear, from which they would diffuse across a membrane into the inner ear. )Source: Thinkstock Images)

OVER 16 months after the secretary, Department of Health Research (DHR), Soumya Swaminathan, wrote to the Drug Controller General of India (DCGI) and senior health ministry officials with a request to ban 37 drugs that she termed “very harmful”, these drugs continue to be freely available in the market. The DCGI had acted on Swaminathan’s email, which was sent on November 12, 2015, seven days later with a suggestion to the health ministry that a committee should be formed to look into this “complex” matter. But the ministry, in response to an RTI filed by The Indian Express, has stated that no such panel had been formed till January 27, 2017.

The 37 fixed-dose combinations (FDCs) listed by Swaminathan in her email are commonly used antibiotics. For example, one drug listed by Swaminathan is Cefpodoxime + Clavulanate, which is used to treat diseases like pharyngitis, urinary tract infection, gonorrhea and pneumonia.

When contacted, Swaminathan, who is also the director-general of Indian Council of Medical Research (ICMR), told The Indian Express: “The DCGI has to take further action. ICMR can only bring to their notice. In fact, they had taken action on many FDCs but much more is needed on irrational combinations. The pharma companies should cooperate.”

According to IMS Health, a global market research company, this drug is sold by more than 70 companies — including Sun Pharma, Pfizer, Wockhardt, Mankind Pharma, Alkem Laboratories, Lupin, Zydus Cadila, Glenmark Pharma, Cipla and Dr Reddy’s Laboratories — in India under different brand names.

In her 2015 email, Swaminathan had stated: ‘’I am attaching a list of irrational antibiotic combinations that need to be banned. The list has been prepared by a group of ID physicians from the Clinical Infectious Disease Society of India (CIDSCON). I agree with them that these are very harmful and will spur additional antibiotic resistance in the community. I hope some action can be taken by DCGI. Am happy to assist in any way possible.’’

This email was sent to B P Sharma, the then health secretary; G N Singh, DCGI, who heads the Central Drugs Standard Control Organization (CDSCO); K L Sharma, joint secretary, health ministry; Jagdish Prasad, director-general of Health Services (DGHS) and S Venkatesh, director, National Centre for Disease Control (NCDC). None of these officials responded to queries sent by The Indian Express seeking comment.

The present health secretary C K Mishra also did not respond to queries sent by The Indian Express. Sun Pharma, Glenmark Pharma and Cipla said they are not aware of Swaminathan’s email and therefore can’t comment on it.

A Pfizer spokesperson told The Indian Express: “We currently market two out of these combinations listed by you and have not been informed of any concerns on either of these. We place utmost emphasis on patient safety and will continue to remain committed to ensuring the safety and quality of our medicines.”

Wockhardt, Mankind Pharma, Alkem Laboratories, Lupin, Zydus Cadila and Dr Reddy’s Laboratories did not respond to requests by The Indian Express seeking comment.

On November 19, 2015, G N Singh, DCGI, wrote a note to the health ministry, stating: “Considering the complexity involved in the issue, examination of each of the antibiotic combinations included in the list forwarded by secretary (DHR) needs to be examined separately considering all aspects of safety, efficacy and present status.”

Singh proposed that a committee of experts under the chairmanship of Swaminathan, comprising experts from institutes like All India Institute of Medical Sciences (AIIMS), New Delhi, “may be constituted for detailed examination and recommendations”.

Singh stated that the proposed committee’s recommendations will enable top health ministry body Drug Technical Advisory Board (DTAB) “to take final decisions through deliberation”.

On January 27, 2017, the health ministry told The Indian Express — in response to an application filed under Right to Information (RTI) Act, 2005 — that no such committee “has been constituted so far by this ministry to examine 37 antibiotic combinations”.

The ministry stated that “three irrational antibiotic combinations (Cefixime + Azithromycin, Ofloxacin + Ornidazole Suspension, and Metronidazole + Norfloxacin) out of 37 mentioned in e-mail of Dr Soumya Swaminathan were banned by the Government vide notifications dated 10.3.2016. However, the Delhi High Court has struck down the said notifications.”

These three drugs were part of the 344 FDCs that were banned on March 10, 2016, by the central government on the recommendation of committee formed under the chairmanship of Professor C K Kokate. This committee, which studied the irrationality of various FDCs, recommended the ban on 344 of them, citing the rising “antibiotic resistance” in the country as one of the reasons. Antibiotic resistance is the ability of a microorganism, which is causing the disease, to withstand the effects of an antibiotic medicine.

On December 1, 2016, Delhi High Court struck down the ban stating that the government had acted in a “haphazard manner”. This January, The Indian Express had also asked the health ministry if there was any committee or any other government department that is currently examining the issue of banning 37 drugs mentioned in Swaminathan’s email. The ministry replied that it has “no such information”.

CIDSCON and Indian Drug Manufacturers Association (IDMA) did not reply to the queries sent by The Indian Express.

The Organisation of Pharmaceutical Producers of India (OPPI) declined to answer queries on behalf of member-companies. D G Shah, secretary-general, Indian Pharmaceutical Alliance (IPA), told The Indian Express: “We are not aware of any communication from the government specific to these 37 FDCs. Some general notices have been put on the website of the Central Drugs Standard Control Organization (CDSCO) and the ministry of health & family welfare about the FDCs from time to time.”

Swaminathan’s email stated that these 37 specific drugs “will spur additional antibiotic resistance in the community”.

On February 1 this year, the DCGI wrote a letter to associations of doctors and pharmacists on the subject of “rational use of antibiotics for limiting antimicrobial resistance”.

The DCGI stated in the letter: “Antibiotic resistance is the result of environmental and behavioural causes. Indiscriminate prescription of antibiotics and laxity of enforcement laws are the main causes of antimicrobial resistance. This may be due to injudicious use of antibiotics in hospitals as well as in private practice apart from easy availability of prescription drugs in the country. In this regard, it is requested that you may kindly sensitise your members by raising awareness for rational use of antibiotics so as to curb antimicrobial resistance in the interest of patient safety.”

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