Month: August 2019

Porphyrins can be covalently attached to graphene edges

first_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore further After doping the substrate with CO, the STM images showed that some of the porphines had a protruding center that shows up as a bright spot. These protrusions were likely CO molecules attached to the metal center of the tetrapyrrole. This means that an Ag atom was coordinated to the tetrapyrrole center demonstrating that even when covalently bound to graphene, the porphine maintained its metal-coordination properties. Additional tests showed that the conductivity of graphene at the edges where the porphines were attached did not change substantially. The thermal stability of the graphene-porphine structure was tested by gradually annealing the sample. The authors note that there was a 17% increase in the percentage of molecules bound to graphene after annealing the sample up to 770 K. Graphene is annealed to Ag(111) at 900 K. When the thermal stability test was taken to this temperature, He, et al. still observed prophines bound to the graphene edges, particularly porphines that have three and four carbons bonded to the graphene edge.This study demonstrated a controlled and precise way to attach tetrapyrrole structures to graphene edges. This has important implications for further research in molecular electronics, sensors, and catalysis. Researchers use microwaves to produce high-quality graphene Credit: Willi Auwärter et al. (—Researchers from Technische Universität München in Germany have succeeded in covalently binding porphine to the edge of a graphene sheet on a Ag(111) substrate using surface-assisted covalent coupling. This provides a proof-of-principle that graphene edges can be functionalized with tetrapyrroles in a precise manner. Furthermore, their work shows that the graphene-porphine structure maintains its electronic and metal-binding properties. Their work appears in Nature Chemistry. “Our findings open new perspectives for the controlled functionalization of graphene nanostructures and the embedding of porphines in graphene sheets,” comments Professor Willi Auwärter who co-authored this study. “We are excited by the potential of the resulting structures to catalyze distinct chemical reactions and anticipate applications in molecular electronics, sensing and optoelectronics.”Tetrapyrroles, molecules that contain the heterocyclic five-member pyrrole ring, are key structures for several important biological molecules. Hemoglobin and chlorophyll, for example, are tetrapyrroles known as porphyrins. Porphyrins coordinate a metal in the center of the tetrapyrrole ring. Additionally, tetrapyrroles are stable molecules that can accommodate a variety of functional groups. Their delocalized electron framework, as well as their metal-binding properties, makes them an interesting study for molecular electronics.In this study, porphine, the simplest tetrapyrrole, was covalently bound to a graphene edge. While prior studies by other groups have linked porphyrins to graphene sheets, they have done so using a more traditional chemistry route in which graphene oxide is reacted with the porphyrin in solution. This leads to a mixture of products and poor control over the porphyrin’s attachment points, which is not conducive to the precision necessary for molecular electronics. He, et al. used surface-assisted coupling to covalently link porphine to graphene. They chose an Ag(111) substrate because of their experience with surface-assisted dehydrogenation reactions with porphines and because Ag(111) only weakly interacts with graphene. According to the research paper, the goal was to use the surface both as a platform for graphene synthesis and to mediate the coupling reaction. The graphene edges needed to be clean and well-defined and the reaction with the porphine needed to be precise and controlled. The Ag(111) allows for this.Once the graphene was grown on the Ag(111) surface, free-base porphines were vapor deposited at room temperature and then the surface was heated to over 620 K to induce the coupling reaction. Scanning tunneling microscopy (STM) and non-contact atomic force microscopy (AFM) with a CO-functionalized tip showed that individual porphines appeared to be covalently linked to the graphene edges. Their studies showed that porphine bonding occurred in four configurations: 1) One C-C bond between the porphine and the graphene edge at the β position on the pyrrole; 2) two C-C bonds between the β pyrrole carbons and the graphene sheet; 3) three C-C bonds, one on a β pyrrole carbon, one bonded to the carbon between two of the pyrroles, and the other on a second β pyrrole position; 4) four C-C bonds with a similar pyrrole-carbon-pyrrole bonding structure as configuration 3, but with an additional C-C on one of the pyrroles. More information: Yuanqin He et al. Fusing tetrapyrroles to graphene edges by surface-assisted covalent coupling, Nature Chemistry (2016). DOI: 10.1038/nchem.2600AbstractSurface-assisted covalent linking of precursor molecules enables the fabrication of low-dimensional nanostructures, which include graphene nanoribbons. One approach to building functional multicomponent systems involves the lateral anchoring of organic heteromolecules to graphene. Here we demonstrate the dehydrogenative coupling of single porphines to graphene edges on the same metal substrate as used for graphene synthesis. The covalent linkages are visualized by scanning probe techniques with submolecular resolution, which directly reveals bonding motifs and electronic features. Distinct configurations are identified that can be steered towards entities predominantly fused to graphene edges through two pyrrole rings by thermal annealing. Furthermore, we succeeded in the concomitant metallation of the macrocycle with substrate atoms and the axial ligation of adducts. Such processes combined with graphene–nanostructure synthesis has the potential to create complex materials systems with tunable functionalities. Journal information: Nature Chemistry Citation: Porphyrins can be covalently attached to graphene edges (2016, September 12) retrieved 18 August 2019 from © 2016 Phys.orglast_img read more

KFC To Test PlantBased Meatless Chicken


Pretty naturally

first_imgSummer is gone now, so all the amazing pop colours that you might have invested in for your makeup arsenal is going to go on a well deserved sabbatical. While in the grey monsoons, it is quite a craving to colour up the day with something bright – but as fashion experts would tell you – the colour should be in your clothes and accessories this season, not in the makeup. This season, go natural. The nude makeup look is polished and pretty and because you’re simply boosting your skin tone, it’ll never appear as if you tried too hard. Also Read – ‘Playing Jojo was emotionally exhausting’Nude should not mean the same thing to all people. Picking flashy colors that complement your complexion will prevent you from looking washed-out. That means honey and taupe for fair skin; tawny and caramel for medium; chocolate, gold and terra-cotta for dark, says makeup expert Nidhi Khurana.For nude makeup we should always start with primer and most importantly use mascara first and last. Depending up on your skin tone, use peach undertone; for fair skin. For medium complexions, pinks and caramels for darker skin tones. Choose a foundation that is slightly lighter than your skin tone and apply to the rounded parts of your face: cheeks, bridge of the nose, chin and forehead. Use powder blushes, highlighters and a soft brush to contour around the hairline, and the outer perimeter of the face.For ideal nude eye apply matted eyes colours like pink, peach and caramel. It gives eyes very nude yet classy look. For lips to look natural you can choose a gloss or a matted lip stick.last_img read more

Classical at its best

first_imgIt was the time when all the classical dance lovers witnessed a great talent in the Capital. Renowned Kuchipudi exponent Meenu Thakur and her disciples performed live at the event Feel India, an initiative of Incredible India and IDTC on 24 April at Hotel Ashok. The performance encompassed a mosaic of classical Kuchipudi pieces however the major attraction of the event was Tarangam performed by Thakur enthralling the present audience and eliciting appreciation and applause from  them. The artistes were later felicitated by ITDC.Thakur is one of the leading Kuchipudi dance exponents. She has flair and grace for an efflorescent dance style Kuchipudi. Her style represents a combination of the feature of Purusha Sampradaya (original male dance tradition) of  Kuchipudi and its Anuroopa (transformation of the male dance style into female interpretation). She has excellent command over technique and abhinaya.last_img read more

Calcutta HC stays Panchayat poll processes till April 16

first_imgKolkata: Calcutta High Court on Thursday directed all processes of the West Bengal rural polls to be suspended till April 16, when the State Election Commission (SEC) will submit a report on the measures it has taken to ensure peaceful filing of nominations by the Opposition.Justice Subrata Talukdar also imposed a fine of Rs 5 lakh on the BJP for misrepresentation, likening the party’s conduct to “forum hopping” after the saffron brigade approached both the high court and the Supreme Court on similar pleas. The state government has decided to move the division Bench of the high court on Friday challenging the single Bench’s verdict. Also Read – Heavy rain hits traffic, flightsThe high court has ordered the SEC to submit on April 16 a comprehensive status report on the poll process, detailing the number of nominations filed and the percentage of nominations rejected, amongst other information.Trinamool counsel and party MP, Kalyan Banerjee, argued both inside the court and outside that according to Article 243-O of the Constitution, courts do not have right to interfere in electoral matters after the election process has begun. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killed”We are approaching a Division Bench against this order,” said Banerjee.The BJP had already moved a caveat before the Division Bench of Justice Biswanath Somadder and Arindam Mukherjee where the TMC is supposed to move their petition challenging the single Bench order.It is learnt that Justice Talukdar will take a decision on resuming the poll process after getting the SEC’s report.Trinamool Congress secretary general Partha Chatterjee said the Opposition has nothing to rejoice as the people of Bengal are with the TMC and its development agenda. “We have full faith in the judiciary. They are trying to delay the election process as they have no organisational strength. Elections will be held today or tomorrow and then it will be proved clearly that the people of the state have full faith in our development agenda. The changes that we have brought about will reflect in the vote box,” Chatterjee said. It may be mentioned that Justice Talukdar’s order came in the wake of a petition moved by the Bengal unit of the BJP, alleging that the ruling Trinamool Congress has resorted to violence to prevent their candidates from filing nominations for the forthcoming Panchayat polls.The Congress welcomed the high court orders. “I salute the high court. At least they are listening to our agony when the government, police and even the State Election Commission are turning a deaf ear to our pleas,” said state Congress president Adhir Chowdhury.”We welcome the decision of the Calcutta High Court,” said MoS heavy industry and Lok Sabha MP Babul Supriyo.Left Front chairman Biman Bose said the verdict of the single Bench has proved that the allegations that we have made are genuine.Elections are scheduled to be held in three phases from May 1, 3 and 5 with the counting happening on May 8. The filing of nominations for the Panchayat polls began on April 2 and ended on April 9. Scrutiny of nominations took place on April 11. The withdrawal of nomination had started on Thursday and with the high court’s order, the process has been stalled.last_img read more

State buys 19 acres of land the highest ever through Direct Land

first_imgKolkata: In a major success of Chief Minister Mamata Banerjee’s “Direct Land Purchase Policy”, the Bengal government has become successful in purchasing 19 acres of land in South 24-Parganas, the highest in the state so far, with the consent of 229 landowners.Banerjee, who had fought for the rights of farmers in Singur where 997 acres of agricultural land was acquired to set up Tata’s small car factory, has assured that her government will never go for “forcible acquisition of land” and the Direct Land Purchase Policy was introduced enabling the government to purchase plots directly from its owners with their consent to develop “infrastructure including roads, railways, bridges, food godowns, drinking water, flood protection works and other similar projects”. Also Read – Heavy rain hits traffic, flightsThe direct purchase of 19 acres of land at Gosaba and Gadkhali in South 24-Parganas has been done only after getting the consent from 229 landowners and is a “great success of the land purchase committee headed by the District Magistrate” when there has been a lot of trouble over setting up of power grid sub-station at Bhangar in the same district. The land has been purchased by the state government through the district authorities to ensure completion of the construction of a bridge over river Bidya connecting Gadkhali and Gasaba Bazar. A portion of the purchased land in Gadkhali while remaining part of the 19 acres is on the other side of the river at Gasaba Bazar. Construction of the bridge is a major project as it will ensure road connectivity with islands in the Sunderbans and the mainland. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe land was purchased from its owners at a rate of Rs 40 lakh per acre and has been registered in the name of the state government. The landowners have been provided with very lucrative money even though their lands were located in such a remote area. The officials have approached the landowners and explained in detail the need of the land in that location. According to an official, the landowners have realised that construction of the bridge is essential for the development of the region that would ensure connectivity with the mainland and at the same time also ensure economic development of the area. “The landowners were given sufficient time to take their decision after explaining the purpose behind purchasing the same. Finally, they were convinced and the consent letter was obtained from 229 landowners,” the official said adding that this is for the first time when 19 acres of land has been directly purchased. The official further explained that the Direct Land Purchase Police is effective in terms of completion of projects as it used to get delayed for non-availability of “small parcels of land”. It helped in the timely completion of projects and proper utilisation of the “public funds”.last_img read more

Family members accuse Green Park Nursing Home of baby swapping

first_imgKolkata: Green Park Nursing home in the city has been accused of baby swapping. Sukanta Biswas, a resident of Mukundapur has brought serious charges against the nursing home authorities of swapping his new born baby and lodged a complaint at the local police station. The nursing home is situated at Netai Nagar under Purva Jadavpur police station.After receiving the complaint, police took prompt action and held two officials of the nursing home for interrogation. In his complaint, Biswas mentioned that he brought his wife Tapasi Biswas to the nursing home for delivery on June 20. He said his wife was admitted to the nursing home at around 5.30 pm. Also Read – Heavy rain hits traffic, flightsThe doctor, who was treating the woman, has been attached to the nursing home. The lady doctor told the family members that the operation would be done at around 6.30 pm. The woman gave birth to a boy child at around 7.27 pm. But the family members of the woman was not allowed to see the baby until 9 pm, when the baby was finally produced before Biswas and his family members.The baby had some deformity in his legs and one hand. The family members alleged that the doctor, earlier on the basis of some clinical tests, confirmed that the baby was absolutely fine and he had no such deformities. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedWhen the family members of the victim raised the issue, the nursing home authorities told them that everything will be alright following a plastic surgery on the baby. Biswas was also advised to take the baby home. The victim’s family members on Thursday staged a demonstration inside the nursing home campus onThursday morning.The family members of the infant took him to NRS Medical College and Hospital, where the baby was denied admission initially. The staff members of the hospital wanted to know from the family members where the delivery was done and who had carried out the operation.Biswas also told the police that his wife had been under the treatment of a lady doctor attached to the private nursing home since November last year. Several tests were performed on the patient from time to time on the basis of which doctor had said the baby was absolutely normal.The family members also alleged that their child had been swapped by some of the staff members of the nursing home immediatelyafter he was born.They also added that after the delivery, one unidentified person came out of the operation theatre with a bag, went straight downstairs and left the nursing home.The family members of the victim have demanded a detailed probe into the incident and stern action against those who will be found guilty.last_img read more

Unique tree on IIT Kharagpur campus attracts botanists from across country

first_imgKolkata: A unique tree on the campus of IIT Kharagpur is now the centre of attraction of botanists all over the country because of its rarity.Botanist Barnali Chakrabarti has stumbled upon a unique 5 in 1 tree. Though the main tree is Bakul (Mimusops), four other varieties like Dumur (Ficus), Neem (Azadirachta), Pipal and Sheora (Streblus) have emerged from certain joints of the same tree.”A blend of two varieties like Assattha (Sacred Fig) emerging from banyan tree or vice-versa or Banyan or Assattha erupting from a Simul tree is not uncommon. But 5 in 1 tree is usually unheard of,” Chakrabarti said. Also Read – Heavy rain hits traffic, flightsAccording to her, the main tree is Bakul (Mimusops). A few feet above the ground from the main stem, two more major trees Dumur (Ficus) and Neem (Azadirachta) have grown as if they are tearing open the Bakul tree stem and coming out. Later, Pipal and Sheora (Streblus) have erupted from the very samejoint at the top.The main Bakul Tree is more than 20 years old, while Dumur and Neem too is more than 10 years old. The last two varieties are relatively new. “There are hundreds of trees on the campus and many of them are unique but this is possibly the most unique one that I have seen,” Chakrabarti said. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe Horticulture section has already enclosed the tree to protect it and a board listing out the names of all the species have been put.”A variety of birds throng the IIT KGP campus because of the greenery all around. When a bird feeds on fruits, it sometimes carries the seeds in its beak or the seeds get stuck to its body parts. As it perches from one tree to another, such a phenomenon may occur.” Chakrabarti added.Barnali Chakrabarti has been promoting green activism on the campus for the past few years. The institute has planted some 3,000 tress on the campus in the last three years and is geared up to plant more trees as soon as monsoon sets in full swing.It may be mentioned that the students of IIT Kharagpur have formed a social group to spread the message of tree conservation and planting trees with deep roots that don’t get uprootedduring storms.last_img read more

Kolkata Police to organise Safe Drive Save Life programme

first_imgKolkata: The Traffic Guard Headquarters of Kolkata Traffic Police will organise a Safe Drive Save Life programme on Friday. The programme will be held at Rangers Club, which senior police officers will be attending.At the same time, in a bid to create awareness on road safety, an inter-school slogan and poster competition was also organised, the final of which is going to be held on Friday. Around 10 students of classes 4 to 12 participated in the same. Also Read – Rain batters Kolkata, cripples normal lifeAn orientation workshop for commuters and drivers will also be organised on Friday. Around 100 people, including 50 drivers of buses, taxis and auto-rickshaws will be attending the workshop. The programme would commence at 12 noon.A video that was prepared by the officers of the Traffic Guard Headquarters to create awareness on road safety, will be shown to the drivers in the orientation workshop. The video was selected as the third best in a competition organised by Kolkata Police.It may be mentioned that Chief Minister Mamata Banerjee had launched the statewide Safe Drive Save Life campaign to check the number of road accidents and it has helped in bringing down the number significantly.last_img read more

Body of 45yearold man found at Bally flat

first_imgKolkata: Mystery shrouds the death of a 45-year-old man whose body was found inside his flat at Bally in Howrah on Monday late night.Police said the victim, Shantanu Chakraborty, was alone in the flat on Saturday as his wife and daughter went to a relative’s house. His wife returned home along with the daughter at night and found him hanging from the ceiling of a room. Locals went to the flat housed on the first floor of the building after hearing the wife’s cry for help and found Shantanu hanging. Also Read – Rain batters Kolkata, cripples normal life They reported the matter to the police. Policemen from Bally police station went to the spot and brought down Shantanu. He was declared brought dead when taken to a nearby hospital. A police officer said they have spotted injury marks on the victim’s legs, which has made the incident mysterious. They are waiting for the autopsy report to ascertain whether it is a case of suicide or homicide. Police spoke to the locals and came to know that the man used to work at a private company. He was ill for the past few days and was also suffering from depression for the past few days.last_img read more