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Bengaluru Monday, 16 July, 2018 - 08:23

When we speak of biodiversity in peninsular India, all eyes and ears move towards the lush green Western Ghats—the well-known biodiversity hotspot. In comparison, the dry forests, scrublands and rocky outcrops that are characteristic of the Deccan plateau are viewed as barren and species-poor. In an exciting discovery, scientists from Indian Institute of Science, Bengaluru, and the Natural History Museum, London, have discovered two endemic species of Fan-throated lizards in these ‘barren’ landscapes.

Fan-throated lizards, as the name suggests, have a fold of loose skin hanging from the throat in males. Also, called dewlap, it is used in communication during the breeding season. In this study, published in the journal Zootaxa, the researchers have described two new species of Fan-throated lizards belonging to the genus Sitana; one from Karnataka and other from Andhra Pradesh. The study which was undertaken in Dr. Praveen Karanth's lab at the Center for Ecological Sciences, Indian Institute of Science, was funded by fellowships from the Department of Biotechnology and  Rufford Small Grants.

Individuals of the genus Sitana are small, ground-dwelling lizards that form an essential part of the food chain in dry, arid landscapes. “Several birds, mammals and snakes prey on these species, and they feed on small insects”, says V. Deepak from IISc, who is the lead author of the study, talking about their role in the ecosystem as prey and predator.

Of the two new species, Sitana gokakensis was found and reported from, and named after Gokak taluk, in Belagavi district of Karnataka. The other, Sitana thondalu, was found in two adjacent areas near the Nagarjuna Sagar reservoir, at the foothills of the Nallamala range in Guntur district, Andhra Pradesh.

The two species are cryptic, meaning that they aren’t easily distinguishable just by their looks. Hence the researchers analysed their genes to tell them apart. They collected tissue samples to extract DNA from a lizard in each of the 12 sites they chose for the study.

“The lizards were hand-captured, and their tail samples were obtained before releasing them. We initially had only eight males between the two species, but once we realised they were cryptic species, we had to collect at least ten males per species to be able to identify them properly”, recalls Deepak. “Since we sampled during the breeding season, we tried to avoid capturing gravid (carrying eggs) females. Males were identified by the full colouration of the dewlap”, he further adds.

The researchers found that the two new species are distributed 500 km apart from each other and are endemic to their localities. S. gokakensis is found in the open rocky dry habitat of the Gokak plateau, characterised by thorny and dwarf succulent plants. S.thondalu, on the other hand, was found in the dry, rocky outcrops with sparse vegetation and stunted trees in Macherla and Nagarjuna Sagar in Guntur district.

The researchers also used specimen data for comparison from their previous study of 200 museum specimens of four different species maintained in various zoological institutions in Odisha, Kolkata and Pune. They used differences in their genetic codes and geographical separation to tell apart the two species as well as determine their endemicity.

“We had a good amount of molecular data that I collected from across India from 107 locations for an earlier genetic study. Hence, we were able to confidently ascertain that these two were endemic to the described localities. In this study, we also sampled extensively in the areas around and intervening the two species to find out if they were geographically isolated”, reasons Dr. Deepak. A phylogenetic tree analysis showed that the two species were genetically different. The deeper and farther away the branches of the species are on the tree, the more genetically distinct they are. In this case, they showed deep divergence, to be considered as separate species.

As expected in cryptic species, morphological measurements showed that the two species had considerable overlap.  Even so, they are used as a standard protocol to help list out diagnostic characters that are useful when describing a new species.

Explaining the usefulness of these measurements, Deepak adds, “Sitana are broadly separated into groups by its dewlap type and colours. Within groups, to identify cryptic species, different morphological measurements may be used. In the case of lizards, they could be a number of certain scales, their size, body ratios or a combination of these”.

This study did not look at the reason behind the endemicity. However, the authors speculate that rocky, barren rivers, with deep peaks and troughs, can be a barrier for species dispersal, as the Sitana cannot climb such terrains. In this case, the rocky Ghataprabha river surrounding the Gokak plateau and the Krishna river along with the Nallamala hills around Nagarjuna Sagar have possibly restricted the distribution range of these species. However, the study urges for a more finer level of detailed sampling required to map out the distribution of the two new species.

It also highlights the importance of these dry-zones for the possible discovery of many other endemic reptilian species. The South Asian lizard genus, Sitana currently has 12 species, with most having been discovered only since the late 90’s. “The region is under represented in terms of data because of poor sampling and lack of systematic studies. They might well be biodiversity rich, harbouring many endemics that can serve as keystone species for conservation of these barren landscapes”, say the authors. More cryptic species are being discovered from the Indian subcontinent, across various taxa, even as we speak. It is therefore important that future studies focus on large sample sizes combined with latest molecular methods, to clearly delineate between species. 

Section: General, Science, Ecology, Deep-dive Source:
Mumbai Thursday, 12 July, 2018 - 16:26

Being big, like an elephant or a rhinoceros, has a significant advantage—no predator would dare tackle such a large animal!  However, some viruses, like the one that infects the single-celled amoeba, are big for a different reason—to sneak into its host, the amoeba. In a new study, researchers from the Indian Institute of Technology Bombay (IIT Bombay), have found a relationship between the number of copies of a particular set of genes and the size of the amoeba viruses that help these viruses to gain easy entry into their host.

Viruses are organisms containing an outer protein coat called the capsid and genetic material, either DNA or RNA. Unlike a bacteria, viruses cannot replicate themselves as they do not contain all the genes required for replication. Hence, they infect a suitable host cell and subvert its normal processes to prepare a few proteins and enzymes needed for their replication. Different viruses use different strategies to gain entry inside the host cell. The amoeba virus uses its size to con its host through the very process used by an amoeba to eat.

In this study, published in the journal Virus Evolution, the researchers elucidate how the amoeba virus increases its size by using a set of essential genes called RDCPs (Repeat Domain Containing Proteins) to expand its genome length and to infect the host once inside the amoeba cell. The research was supported by the Department of Science and Technology and the Department of Biotechnology.

“It has been observed that in amoebal viruses, the number of RDCPs increases with increase in the genome size, and most of these proteins are located at the end of the genome. The multiple copies of RDCPs could be the result of their lineage-specific expansion in giant viruses. Their sheer number adds up and increases the genome size”, says Prof. Kiran Kondabagil from IIT Bombay, in an interview with Research Matters. This finding is an exception to the earlier belief that viruses, thriving inside other cells as intracellular parasites, have small genomes.

So, how does being big help the virus? Amoeba eats through a process called phagocytosis, where it engulfs its food, usually bacteria, and absorbs it into its cell. Hence, the amoeba virus tries to look like a bacteria by growing big, to draw the amoeba's attention and sneak into its cell when the hapless amoeba engulfs it mistaking it for bacteria. “The threshold particle size for successful phagocytosis in amoeba is thought to be 0.5 µm. As it predates on many microorganisms, we think that the amoebal viruses need to be of a similar size range”, says Prof. Kondabagil.

Once the virus enters the amoebal cell, it unleashes a set of processes that allow it to hijack the cellular machinery to help its replication. The host's defence mechanism is the last hurdle in doing so. Inside the amoebal cells are bags of acerbic enzymes called lysosomes, which, digest the engulfed bacterium in the phagosome (a sac-like structure) to derive nourishment in the normal process of phagocytosis.

When the amoebal virus enters the host cell, it needs to avoid contact with lysosomes at any cost!  The researchers found that the amoebal virus escapes being digested in the host cell by using the RDCP genes, whose products mark the phagosomes differently so that lysosomes fail to recognise them as fit for digestion. These genes also subvert the defence proteins of the host to avoid premature destruction. Once a virus has infected an amoeba, it is not advantageous for the virus inside to have another virus infecting the same cell. Therefore, through the RDCP proteins, the virus modifies the shape and structure of the infected cell in a way that no new virus can infect it.

The acquisition of more copies of these genes themselves, in the genome of the virus, is also exciting! “The virus may acquire the RDCP genes from different genetic elements that move around, through a process called horizontal gene transfer", says Prof. Kondabagil. Horizontal gene transfer is a process where genes from any organism, irrespective of the species they belong to, are acquired by an organism. The virus also could then increase the number of RDCP genes through duplication.

The study convincingly explains the role of RDCP genes that help the amoebal virus gain entry into the host and lets it survive despite the host's defence mechanisms. These genes, present in multiple copies at the terminal ends of the viral genome,  also protects the central core of the genome.  “The numeric correlation of RDCPs with genome size might have an evolutionary significance. Their arrangement may be crucial for these viruses to adapt to a wide variety of hosts and out-compete prokaryotes and other viruses", says Prof. Kondabagil, talking about the importance of the findings, which could also help us understand the evolution of viruses.

Section: General, Science, Health, Deep-dive Source:
Bengaluru Thursday, 12 July, 2018 - 14:52

When a disaster strikes, every moment that is saved could help save a few precious lives. Now, a recent study by researchers from the Indian Institute of Technology Kharagpur has proposed a mechanism in which faster, cheaper and personalised response could be provided to the victims during disasters with the use of Wireless Body Area Networks (WBANs).

A wireless body area network is a network of sensors connected to the human body, which generate a variety of data related to one’s health, including pulse rate, blood pressure, temperature and other vitals at periodic intervals. The collected data is then transmitted to a centralised processing system that can analyse and can direct health-care professionals to take appropriate actions. 

In a post-disaster scenario, where immobilised victims are typically concentrated in crowded relief camps, multiple medical signals transmitted by WBANs could congest the network. As a result, the healthcare professionals attending these victims remotely would lose out on getting accurate readings from many patients. 

The researchers of the study suggest creating disease-specific groups of patients based on the medical data to address the above challenge. They have used models from social network analysis which can group and divide people based on the kinds of diseases prevalent and the likelihood of them spreading. The suggested mechanism works well in containing the spread of communicable diseases like cholera which are common in the post-disaster period due to the non-availability of clean water.

The proposed improvisation helps healthcare workers cater to the most critical groups first, and based on their expertise these workers can be connected to the neediest patients. For example, a cardiac specialist can address the group having the highest incidence of heart-related issues, and an orthopaedic could treat the group with patients suffering from blood loss or trauma. 

Through simulations, the researchers have also shown that the proposed model is cost-effective with minimum delay, and has higher network reliability than existing models.
 

Section: General, Science, Technology, Society, News Source:
Mandi Thursday, 12 July, 2018 - 08:10

Chikungunya fever is a major public health issue that infects many during the monsoon season. The most recent outbreak in India was in 2016, and in the last three years, the number of chikungunya cases in India has increased by a whopping 390 per cent. Caused by a mosquito-borne virus, there are no vaccines or specific treatments for this disease at the moment. Now, researchers at the Indian Institute of Technology Mandi have been studying regions of the Chikungunya virus proteome—the entire set of proteins that can be expressed by an organism—in the hopes of designing a vaccine or a drug against it.

‘Chikungunya’ is a Makonde (a Tanzanian ethnic tribe) word which means ‘the one which bends up’. The symptoms of the disease include fever and severe joint pains. While the illness usually lasts for about five to seven days, in some cases, the patient may continue to suffer from severe joint pains for up to a month, giving the disease its name. The chikungunya virus is small and spherical and is transmitted by the Aedes aegypti and Aedes albopictus mosquitoes.

In a study published in the journal Nature, the researchers looked at how often intrinsically disordered proteins (IDPs) and their regions (IDPRs) were found in the Chikungunya virus proteome. These proteins are a part of the ‘Dark Proteome’ about which not much is known. Scientists believe that they are either a set of many peptide segments or a whole protein that doesn’t have a unique three-dimensional structure within a cell but performs many biological functions, like cell cycle regulation, controlling signal pathways and the maintenance of viral proteomes.

“We have analysed the abundance and functionality of IDPs/IDPRs in the Chikungunya virus proteins that are involved in the replication and maturation of the virus. It is likely that these IDPs/IDPRs can serve as novel targets for disorder based drug design”, says the researchers on the goal of their study.

Since some proteins in the Chikungunya virus are a part of the Dark Proteome, which does not have a three-dimensional structure, they can’t be studied using conventional methods like X-Ray crystallography (bouncing x-rays off the crystalline structure to determine its shape) or using an electron microscope. Instead, the researchers used the polypeptide sequence from an African strain of the Chikungunya virus to find disordered proteins that make up the dark proteome. They studied this strain because it is the most viral Chikungunya strain.

Intrinsically disordered proteins are hydrophilic and are more attracted to water than proteins that have a defined three-dimensional structure—a likely reason why they are disordered. They are promiscuous binders and can be involved in numerous interactions with many partners. They act as an essential hub in protein-to-protein interaction networks that can regulate multiple signalling pathways at a time. These disordered regions represent new and attractive targets for drug design.

“Several reports suggested that IDPs/IDPRs play a central role in various molecular recognition events and protein-protein interaction networks. Some IDPs/IDPRs can undergo at least partial disorder-to-order transitions, and form a specific three-dimensional structure when they get involved in interactions with specific binding partners that are needed for recognition, signalling, control, and regulation”, explain the researchers. The specific binding property of the Dark Proteome is so exciting because the unique structure that is formed can be used as a target site for a new Chikungunya drug.

The study found that the outer covering of the virus, called the capsid protein, is entirely disordered. Changes in two proteins, E1 and E2, of the dark proteome that were caused by mutations has helped the virus to propagate much better in the Aedes aegypti and Aedes albopictus mosquitoes. Since the role of IDPRs is well understood in the regulation of the life cycle of viruses, research has moved towards the development of disorder-protein based drug discovery strategies.

The study suggests that intrinsically disordered protein regions play an essential role in the flexibility of the proteome structure and the diversity of its functions. “The disordered side of the proteome may provide a new angle to study pathogenic characteristics and to understand the virus-host interaction mechanism”, remark the authors of the study.

Section: General, Science, Health, News Source:
Mumbai Wednesday, 11 July, 2018 - 17:54

एक अध्ययन में दर्शाया गया है कि क्रिस्टलीकरण से कैसे किसी पदार्थ का आकार  बदला जा सकता है। 

लचीली सतहें जैसे पत्तियाँ और पंखुड़ियाँ, हर ओर नज़र आती हैं। जैसे जैसे वे पनपती हैं, सपाट नहीं रहतीं बल्कि सिकुड़ जाती हैं या टेढ़ी मेढ़ी हो जाती हैं। ऐसा इसलिए होता है कि पत्तों या पंखुड़ियों को सपाट रखने में कहीं ज़्यादा ऊर्जा लगती है बजाय मोड़ने के। वाहनों में लगने वाली धातु की चादर जैसी कई वस्तुओं के लिए  सिकुड़ापन और टेढ़ा मेढ़ा पन अनुपयुक्त होगा, पर कई दूसरे इस्तेमालों के लिए ऐसे टेढ़े और सिकुड़ेपन की ही आवश्यकता हो सकती है। नेचर कम्युनिकेशन्स नामक जर्नल में, भारतीय विज्ञान संस्थान (IISc), भारतीय प्रौद्योगिक संसथान (IIT) मुंबई और रामन रिसर्च इंस्टिट्यूट (RRI) के शोधकर्ताओं के द्वारा किये गए अनुसंधान से  पता लगाया गया है कि कैसे पदार्थ इस तरह से विकृत हो जाते हैं और किस प्रकार से नियंत्रण करके वांछित गुणों के पदार्थों का निर्माण किया जा सकता है।  

अनुसंधानकर्ताओं ने छड़ों  के आकार के वायरस का अध्ययन किया जो अपने आप पास में आकर एक मोनोलेयर (एक इकाई मोटाई यानी एक माइक्रोन की  एक महीन चादर का  तकनीकी नाम) बन जाते है।  आरम्भ में यह छड़ियाँ मोनोलेयर के अंदर कहीं भी इधर उधर आ जा सकती हैं जिससे ‘कोलाइडल मेम्ब्रेन’ बन जाता है। तापमान घटाने से मोनोलेयर घनीकृत होकर क्रिस्टलीय स्वरूप ले लेते है। मगर बजाय इसके कि मोनोलेयर एक चिकनी और सपाट सतह बनायें, वे एक खुरदुरी और वक्र सतह बनाते हैं। ऐसा तब होता है जब मूल इकाई (वायरस), कायरल हो। कायरल उस वस्तु को कहते हैं जो अपने और दर्पण के अपने ही प्रतिबिम्ब से अलग थलग पहचाना जाये, जैसे कि अपना हाथ। दाहिने और बाएँ  हाथों को दर्पण के सामने रखने पर भली भाँति पहचाना जा सकता कि कौन सा बायाँ है और कौन सा दायाँ।

भारतीय विज्ञान संस्थान (IISc) की डॉ प्रेमा शर्मा ने  प्रयोगात्मक कार्य करने वाले इस दल का नेतृत्व किया है। उनका कहना है कि हमारा काम बुनियादी है और अलाइन्ड नैनोरॉड्स (aligned nanorods) के मोनोलेयर बनाने के काम से सम्बन्ध रखता है। भारतीय प्रौद्योगिक संस्थान  (IIT) मुंबई के डॉ अनिर्बान साईं  के नेतृत्व की एक टीम ने इस परिणाम का सैद्धांतिक मॉडेलिंग किया है  जिससे इन प्रायोगिक नतीजों को समझने और उनकी व्याख्या करने में मदद मिली है।

अनुसन्धानकर्ताओं को पता चला कि क्रिस्टलीकरण से रचित खुरदुरापन और वक्रता को जितना चाहो उतना  ठीक  किया जा सकता है। ये दोनों अभिलक्षण इस चीज़ पर निर्भर करते हैं कि कितने न्यूक्लिएशन  साइट्स (nucleation sites) (कोलॉइडल मेमब्रेन्स  के  घनीकरण होने की जगह) हैं। “हम प्रत्यक्ष रूप से न्यूक्लिएशन सेंटर की संख्या नहीं नियंत्रित कर रहे हैं। मगर बड़े कोलॉइडल मेम्ब्रेन्स के कारण अधिक न्यूक्लिएशन सेंटर बनते देखे गए हैं। न्यूक्लिएशन सेंटर नियंत्रित करने का दूसरा तरीका  है कि सुपरकूलिंग के परिमाण को नियंत्रित करें, अर्थात ये नियंत्रित करें कि तरल मेम्ब्रेन्स को क्रिस्टलीकरण के तापमान से  कितना नीचे लाया जाए।”, डॉ शर्मा कहती हैं।

प्रयोगों से प्राप्त और परिणामों को समझने और विवेचना करने के लिए भारतीय प्रौद्योगिक संस्थान (IIT) मुंबई  के डॉ साईं के अनुसन्धान दल ने इस प्रणाली का कम्प्यूटर अनुकरण किया। एक परत के रूप में  व्यवस्थित छड़ सरीखे परमाणुओं का एक द्वि आयाम का मॉडल बनाया और उन्हें परस्पर प्रतिक्रिया करने दिया गया। ये निष्कर्ष निकला कि छड़ों की सम व्यवस्था अस्थाई होती है और इस तरह डॉ शर्मा के प्रयोगात्मक परिणामों को सफलतापूर्वक प्रतिपादित कर सके। डॉ साईं कहते हैं, “हम मेमब्रेन्स के घनीकरण से बनने वाले किसी भी ढाँचे के विशिष्ट स्वरूप की प्रतिलिपि की  रचना कर सकते हैं।”

द्रव से क्रिस्टलीकरण की अवस्थान्तर के अध्ययन में यह अनुसन्धान वैज्ञानिक दृष्टि से सहायक सिद्ध होगा। “नैनो रॉड्स के संयोजन से मनचाही गुणोंवाली परतों के बनाने की संभावित तकनीकी उपयोगों के क्षेत्र में भी ये काम आएगा। सौर सेल और LED जैसे उपकरणों में नैनोरोड अरे ज्योमेट्री काफी प्रचलित है अतः इन क्षेत्रों में कुछ अप्रत्यक्ष दूरगामी प्रभाव भी हो सकते हैं।”, डॉ शर्मा कहते हैं। वे आगे कहते हैं, “मगर ध्यान रहे कि अभी तक हमारे काम का सौर सेल पर  प्रत्यक्ष प्रभाव नहीं  देखा गया है।” 

Section: General, Science, Technology, Deep-dive Source:
Mumbai Wednesday, 11 July, 2018 - 14:33

In a new study, researchers at the Indian Institute of Technology Bombay, have designed a biosensor using gold nanoparticles that can identify the presence of a protein called alpha-synuclein.  The newly developed biosensor uses optical fibres to identify these proteins even in very low concentrations and can do so in just 15 minutes of time.

Alpha-synuclein is a protein found in our brain and is associated with the neurons that control our body movement. Studies indicate that abnormal deposition and aggregation of these into its amyloid fibrils, which are insoluble protein fibres, can cause neurodegenerative conditions like Parkinson’s disease. Hence, early, accurate and easy detection of alpha-synuclein amyloid fibrils is essential to prevent the progression of the disease.

A biosensor uses a biological component, like an enzyme, or a protein receptor, or an antibody that can selectively bind or react with the target molecule which is to be detected or estimated. In the newly developed fibre-optic biosensor, an optical fibre is used to transmit incident light from the source to the biological component and the emitted light is detected by a detector. In this study, published in the journal Sensors and Actuators B: Chemical, the researchers have developed a U-shaped biosensor that comprises of a layer of gold nanoparticles on which chitosan—a carbohydrate molecule—is attached. Chitosan can selectively bind with alpha-synuclein monomers and the fibrils.

The gold nanoparticles used in the study contain free electrons that oscillate and form an electron wave on interacting with incident light. When the frequency of electron wave oscillation matches with the frequency of the incident light radiation, specific wavelength from the incident light is absorbed by the metal, which is recorded. When alpha-synuclein molecules bind with chitosan molecules, the resonant frequency and the wavelength of the absorbed light changes, thus enabling their detection.

Although both the monomer and the fibril bind with chitosan, their resonant frequency, the corresponding wavelength of absorption and the amount of absorption are different. Further, the study shows that the rate of binding of the monomer is faster than that of the fibril. When the researchers plotted the amount of light absorbed against time, they saw a sharp rise for the monomer, indicating that the monomer binds with chitosan quickly. When they plotted the same graph for the fibril, they observed a gradual increase, which made it evident that the fibril binds slowly with chitosan. Thus, the difference in the amount of light absorbed and the rate of absorption helps to tell the two apart. The biosensor also works even when the concentration of the protein is as low as 70 nM.

This study can help in the detection and diagnosis of neurodegenerative diseases, thereby, aid in improving the quality of life for the many who are suffering from such conditions.
 

Section: General, Science, Technology, Health, News Source:
Bengaluru Wednesday, 11 July, 2018 - 07:29

Researchers develop a highly effective solution for recovering green sand in small and medium foundries.

About 70% of the cast metal objects around us, from bathroom taps to automobile gearboxes, are manufactured in foundries using a method called sand casting. Molten metal is poured into moulds made from green sand---a mixture of sand (about 80%) and clay (about 10%). At high temperatures of about 1500℃ required for casting, clay forms a coating on the sand particles, and the sand becomes unusable for further casting. The disposal of such sand has severe environmental and cost implications, particularly for small foundries. In a new study, researchers from the Indian Institute of Technology Bombay (IIT Bombay) have demonstrated a practical and economical way to reuse this green sand.

Although existing methods for reclaiming green sand are capable of processing many tons of sand per hour, they are expensive. Since about 80% of the 4600 foundries in India are of small and medium scale, these methods are unaffordable for them as these foundries can reclaim only about 1000 kg of sand per day. The only viable solution then is to dispose of the green sand by dumping them in water bodies and land. Since used green sand contains heavy metals like lead and tin, which leach into the ground causing water pollution, environmental laws restrict such dumping. On the other hand, buying fresh sand is now expensive since sand mining is banned in most states, further increasing the cost for small and medium scale foundries. Thus, reclaiming used green sand in a cost-effective and scalable approach turns out to be an attractive proposal.

In this study, researchers led by Prof. Sanjay Mahajani of IIT Bombay have proposed mechanical methods to reclaim the sand as opposed to the expensive heat treatment method at 800℃. The team has developed a better, economical and efficient approach to remove the clay using an abrasion and sieving unit.

The key to reclaim the sand is to remove the layer of clay deposited on the sand particles. The team explored various methods to remove the clay deposit mechanically. In the first method the researchers placed the sand in a vertical tube and used a supply of compressed air to enable rubbing of sand particles against each other. In the second case of a horizontal tube is used instead of the vertical tube. This enables additional rubbing of the sand against the walls of the container. Another method made use of small weights to increase the rubbing action or abrasion and a sieve to separate the removed layer of clay. The researchers evaluated the cost and noted the percentage of clay after reclamation for each of the methods.

The researchers found that the best option was the one that used abrasion and sieving. Prof. Mahajani suggested a two stage method where the sand particles are rubbed in the against pebbles in the first stage and sieved in the second stage to separate the clay particles. The sand to be reclaimed is placed in a rotating drum and pebbles of a hard stone such as agate are used for rubbing the clay off the sand particles. The weight of the pebbles needs to be chosen carefully so that clay is removed but the sand particles are not crushed. Pebbles weighing around 40g were found suitable. The second stage uses a rotating drum with a 50 micron (about the thickness of human hair) mesh that acts as a sieve. The sand particles rub against each other in this stage. Since clay particles are smaller in size than sand particles, they pass through the sieve and are collected and disposed of, leaving behind the reusable sand.

In some cases, if the green sand has a substantial moisture content, the efficiency of reclamation is reduced. Hence, the unit has a heater and blower system which first dries the sand before the reclamation process starts.The study found that the rotation speed of the device, the weight and size of agate pebbles, the moisture content of sand and the temperature were some of the factors that can influence the performance of the device.

So how efficient and economical is the proposed new method? The researchers found out that only 2.2% clay remained after the proposed two stage  method at the cost of Rs. 550 per ton, while the corresponding numbers were 4.4% at Rs. 2700 per ton for the vertical tube method and 2.2% at Rs. 5600 per ton for the horizontal tube  method. Although the setup and installation cost of the proposed two-stage unit is more than other conventional setups, the operating cost is much lower.  The process results in a massive 83% savings over buying fresh sand, which costs about Rs 3200 per ton.

The researchers have set up a working prototype of the proposed unit which is capable of processing 100 kg of green sand per hour. "The two-stage device has been installed in the Government Polytechnic College, Kolhapur, Maharashtra", says Prof. Mahajani, talking about the success they have seen so far. "Kolhapur is a large foundry cluster, and many small foundries are operational in this area. We are collecting the waste green sand from small-scale foundries and reclaiming using this prototype. As far as field trial results are concerned, they were found to be satisfactory. They appreciated our work and also started to use our reclaimed sand", he adds.

The study, published in the Journal of Materials Processing Technology, brings in an invention that caters to the needs of small and medium scale foundry owners, who can now abide by the environmental laws and obtain reusable, clean sand with minimal impacts on the environment. The researchers are now improvising on this innovation. "We are working on a hybrid unit which facilitates both thermal and mechanical reclamation. We are also trying to prevent the heat loss as much as possible to reduce the processing cost", shares Prof. Mahajani before signing off. 

Section: General, Science, Technology, Deep-dive Source:
Bengaluru Tuesday, 10 July, 2018 - 08:56

What do we mean when we say we wish to ‘cool’ something down? In day to day life, we simply mean, that its temperature be reduced or heat from the material should be removed. But what actually happens inside the material being cooled? How much heat can we remove from a material? Can we reach temperatures almost equal to absolute zero i.e. 0 Kelvin? We know that all matter is made up of large number of atoms which are in a state of incessant back and forth motion. This energy due to motion, or kinetic energy, is perceived as temperature. Cooling any material essentially means reducing the kinetic energy of the atoms in the material. When a system is sufficiently cold, the kinetic energy is negligible. In this case, the potential energy, which in dilute gases of atoms is very small, starts to determine interaction among the atoms, and so plays a major role in deciding the properties of the material. As this happens, very basic quantum properties which would otherwise be masked at higher temperatures reveal themselves. Cooling systems to such regimes is therefore of critical importance for many physics experiments, and often the biggest challenge to overcome. 

Researchers Sourav Dutta and Sadiq Rangwala at the Raman Research Institute (RRI), Bengaluru have developed a novel method of cooling ions based on a phenomenon called resonant charge exchange (RCE). “What we demonstrate in this work from RRI is a novel and very efficient way of cooling ions by pick-pocketing the electron from the atom. New cooling mechanisms are very rare and have ramifications for future advances,” says Prof. Sadiq Rangwala, who is  an author of this study. Their study, published as a Rapid Communication in the journal Physical Review A, was supported by DST, under the DST-INSPIRE Faculty Award, and Indo French Centre for the Promotion of Advanced Research (CEFIPRA). 

As the atoms and ions in the gaseous phase tend to fly apart, even when very cold, chances of studying their interaction is greatly reduced. Thus if one wishes to study an atom-ion interaction for a longer time, some form of geometric confinement of the ions and atoms, in other words “trapping” is required. Usually, trapping is done using a combination of electric, magnetic and light fields. In the RRI experiments, this led to two, co-centred globes of trapped ions and atoms, millimetres in extent, suspended in very high vacuum at the centre of a steel experimental chamber with many windows.

Once the motion of the ion is restricted to the volume of the trap, the ion/atom are conventionally cooled by two methods. The first approach relies on “laser cooling” where, particles of light or photons from a laser are scattered by the atom/ion, undergoing multiple absorption and emission. The multiple collisions result in a recoil for each absorption and emission in a very specific way, leading to atom/ion cooling. The second approach relies on “sympathetic cooling”, where atoms which are already laser-cooled to a lower temperature collide with a higher temperature ion, thus reducing the ion’s kinetic energy. Over the course of multiple collisions, the ion loses most of its kinetic energy. However, both of these processes require multiple collisions since each collision only removes a fraction of the kinetic energy from the ion.

In contrast, in this new cooling method based on RCE, almost the entire kinetic energy of the ion is removed in a single collision between a colliding ion and the parent atom. “Cooling by resonant charge exchange is essentially a ‘swap cooling’ mechanism where an electron is transferred to a fast ion from a pre-cooled parent atom held essentially at rest. This results in an ion that is almost at rest. The mechanism works in homo-nuclear ion-atom systems i.e. when the ion and the atom are of same species, such as the Cesium-Cesium+ combination”, says Dr. Sourav Dutta, who was a DST-INSPIRE funded Faculty fellow at RRI. He is currently an Assistant Professor at the Department of Physics, IISER Bhopal. The swap cooling technique is found to be more efficient than other conventional methods, since a single collision produces a cold ion. Under similar experimental conditions, the per-collision cooling via RCE mechanism was found to be about 100 times higher than cooling via elastic collisions.

Experiments across the world are attempting to study ultracold collisions for the combined ion-atom system which has so far been elusive. According to the authors, this study underlines the importance of RCE as a mechanism in ion-atom systems and is an instrumental mechanism for ion-atom experiments in the ultracold regime.

Section: General, Science, Deep-dive Source:
Mumbai Monday, 9 July, 2018 - 06:53

The variability of monsoon rains due to climate change affects Marathwada and Vidarbha regions the most, says a district level study.

India is ranked 6th in the list of countries most vulnerable to climate change, according to Global Climate Risk Index and it is evident from the frequent occurrence of extreme weather events like floods, cyclones and droughts. Climate change affects the monsoon rains that drive agriculture in India. Though many studies have tried to assess the impact of climate change at a regional level, the policies based on such studies fail to address the grievances of agriculture and farming sector at smaller, district levels. In a study, researchers from the Indian Institute of Technology Bombay (IIT Bombay) have investigated the impact of climate change on agriculture in the districts of Maharashtra.

The seasonal monsoon winds, blowing from the south-west and the north-east directions, are moisture-laden and bring in the yearly monsoon rains. These rains are critical to almost 60% of India’s rain-fed agriculture and the timely arrival and adequacy of monsoon winds plays a vital role in our farming practices. These winds vary across seasons, across years and also across decades, and this variation is commonly known as monsoon variability.

The study, published in the journal Science of the Total Environment, has tried to understand monsoon variability in the context of the changing climate. The study analysed daily rainfall data collected from 34 districts of Maharashtra for 62 years between 1951 and 2013. It took into account the increase in the number of consecutive days with no rainfall (dry spells) and a decrease in the successive days where rainfall exceeded the minimum required amount (wet spells) during this period. It also noted the fluctuations in the daily rainfall patterns; including extreme rainfall events, characterised by heavy and very heavy rainfall.
Based on these data points, the researchers calculated a ‘monsoon variability index’ for each of the districts studied. “The study tries to understand how monsoon variability indices are impacting the productivity of major crops in the highly vulnerable districts of Maharashtra. The methods used in this study can be adopted by administrative units across the world”, says Prof. Devanathan Parthasarathy from IIT Bombay, who led the study.

The researchers found that all the districts considered in the study had an increase in the number of dry spells over the years. However, they observed significant differences in other monsoon variability indicators like extreme rainfall events, the number of wet spells and the fluctuations of the rain pattern.

The researchers then ranked the districts based on the monsoon variability index and found that the regions of Vidarbha and Marathwada were most vulnerable to climate change. It is of little surprise that these two regions also have the highest farmer suicides in the state. The researchers point out that monsoon variability leads to a reduction in the average yield of crops and crop failures.

“Lack of irrigation facilities, climate variability, inefficient agricultural markets, and low awareness of government schemes or programs are the other major reasons for low productivity in these regions”, remarks Ms Deepika Swami, an author of the study.

The researchers also emphasise the need to assess the differences in climate variability of different regions and to follow agricultural practices based on these conditions. Currently, the State Action Plan on Climate Change (SAPCC) formulates agricultural-based policies at a state level. However, with distinct differences at a regional level, a more comprehensive action plan on climate change needs to be formulated, say the researchers.

“To adapt to the changing trends in climate variability, we first need to look at the situation of each region independently. We should not propose adaptive measures applicable to the entire state or a larger area”, says Dr Parthasarathy, talking about how we could tackle the adverse effects of climate change on agriculture.

The results of the study also identified crops that are most affected by the changing climate. Traditional crops of the region such as sugarcane, sorghum ,and groundnut were found to be the most affected due to monsoon variability. On the other hand, the productivity of cotton and pigeon pea were seen to be the least affected.

The researchers share some suggestions on how we could protect the interests of our farmers. “A shift from current agricultural practices to alternate ones, shift in sowing/harvesting dates, expanding diversity of seeds, alternate means of irrigation, alternative livelihood options, and regulation of crop markets are few of the provisions that can be followed in order to adapt to changing trends in climate variability”, signs off Dr. Parthasarathy.

Section: General, Science, Ecology, Society, Deep-dive Source:
Mumbai Friday, 6 July, 2018 - 07:45

Researchers from IIT Bombay use simulations to predict future shoreline changes in Paradip Port of Odisha, India.

Among the many impacts of human-induced climate change is that it may change the shorelines across the world. Change in the intensity and pattern of winds, waves, tides, and currents threaten many cities that were once proud of their coasts. But, how exactly does climate change affect the ports on these shores, and what can port authorities do to be prepared for these changes? Using climate modelling experiments, researchers from Indian Institute of Technology Bombay have simulated what was, and what can be the state of shorelines, focusing mainly on the Paradip Port of Odisha. They have predicted an increase in the wind speed, wave height and transport of sand along the coast.

Paradip Port is a deep-water port on the east coast of India and is situated between the cities of Kolkata and Visakhapatnam. Once a mangrove swamp that was used by locals for fishing and wood collection, it is now India’s eighth major port. In the last 60 years since it started operations, the port and the coastline have been stable. However, in the recent years, they seem to be facing higher levels of erosion and deposition of sand, primarily due to climate change. Climate change refers to the change in the average weather condition over a relatively longer period of time i.e. longer than 10 years. This includes changes in sea and land temperatures, intensity and patterns of wind and rainfall.

“The impact of climate change is highly site-specific or region-specific. Whatever happens in coasts of England or Dubai will not necessarily be valid in Indian coasts. We have about 7000 kilometres of coastline, and it is not likely that the impact of climate change will be the same throughout the coastline”, remarks Prof. Deo.

The researchers of the study used a climate model resulting from the ‘Coordinated Regional Climate Downscaling Experiment’ (CORDEX), developed by the World Climate Research Program. They simulated waves in two-time slices, from 1981 to 2005 and from 2011 to 2035, and thereafter they estimated the sediment transport and shoreline changes during these time periods. The study assumes no construction or developmental activities on the coastline for the next 25 years and does not account for the increase in sea-levels due to global warming which was found to be very small in some of the previous studies. Hence, the predictions are the ‘bare minimum’ changes that can be expected at the Paradip Port.

“Impact of climate change on shorelines is not necessarily restricted to ocean parameters alone. We also have to study socio-economic parameters such as a rise in the future human population living along coastlines, evolving road networks, infrastructure, tourism, etc.”, points out Prof. Deo on the scope of the study.

The study predicts that Paradip Port may see an increase of 19% in mean wind speeds and 32% in mean wave heights in the next 25 years. Going forward, we could observe many tall waves compared to shorter waves, along with a change in their direction of attack, say the researchers. They also predict that littoral drift—the transport of sand particles towards the shores due to waves—may increase by 37% and 24% on the net and gross volumes. 

In many ports across the world, a structure to reduce the intensity of wave action and thereby reduce coastal erosion, called breakwater, is built. Paradip also has two breakwaters; one to the north with a length of about 500 metres, and another to the south which is about 1200 metres long. The researchers predict that due to climate change, the shoreline to the south of the breakwaters will face a greater extent of erosion, which may go up by 4 to 8 metres compared to the current levels. 

In Paradip, the port authorities are already building an offshore breakwater that is 1600 metres long to counter the current erosion. The results from this study may help them to budget and strategise the construction by making it futureproof, the researchers believe. They soon plan to discuss the predictions with the authorities of Paradip Port.

The researchers also suggest alternative strategies to minimise the effects of climate change on our shorelines. Restricting human intervention in these areas to the minimum, balancing the need for developmental activities and conservation, and following the coastal zone regulation norms goes a long way in safeguarding our coasts, they say. Also, assessing the impacts of proposed irrigation projects that could cause water-logging and intrusion of salinity, and planning for activities like beach nourishment, dune restorations, afforestation, mangrove conservation could also help.

“People must know that climate will not remain the same in the future, it will change. Most probably, it will result in intensified climatic conditions, and hence future planners of the coastal ecosystem should take into account the changing climate and devise the mitigation strategies accordingly, rather than basing strategies on past climatic conditions”, suggests Prof. Deo.

Section: General, Science, Engineering, Deep-dive Source:

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