Citation: Nanoparticles Generate Supersonic Shock Waves to Target Cancer (2008, January 16) retrieved 18 August 2019 from https://phys.org/news/2008-01-nanoparticles-supersonic-cancer.html By mixing nanomaterials that act as fuel and oxidizer, researchers have created a combustible nano explosive that can generate shock waves with Mach numbers up to 3. The team of researchers, a collaboration from the University of Missouri-Columbia (UMC) and the U.S. Army, hope that this nano-sized “smart bomb” can target drug delivery to cancer cells, and leave healthy cells unharmed. Their study is published in a recent issue of Applied Physics Letters.“Nanoengineered thermites can produce shock waves, and their properties are similar to some primary lead-based explosives,” Shubhra Gangopadhyay, Professor of Electrical and Computer Engineering at UMC, told PhysOrg.com. “Hence these materials may be able to replace lead-based primary explosives. We are also able to integrate this material with micro-chip technology and produce shock waves using these compact micro-chip systems. This micro system has many applications in defense, as well as in life sciences, such as targeted drug and gene delivery.”The researchers explain that nanothermite composites, made of metallic fuel and inorganic oxidizer, have “outstanding” combustion characteristics. Mixing a low-density composite of copper oxide nanorods (fuel) and aluminum nanoparticles (oxidizer) results in a large contact area between the fuel and oxidizer. On the nanoscale, the low density and large contact area of the nanothermite composite can lead to a fast-propagating combustion.The team tested the combustion in a shock tube studded with optical fibers and pressure sensors to measure the combustion wave speed. They found that the nano composites could generate combustion waves with velocities ranging from 1500 to 2300 meters per second, which is in the Mach 3 range.The power of these nano explosives could lead to a breakthrough in drug delivery for cancer and HIV, the researchers explain. First, drugs would be administered with a needle as usual, dispersing through the entire body. But then a hand-held device aimed at the tumor would send a pulse into the tumor. The shock waves created by the pulse would make tiny holes in the cells it was aimed at, allowing the drug to enter the tumor cells. Further, the force of the shock waves would push the drugs to those cells within milliseconds.The researchers have tested the method on animal tissue, and have demonstrated a 99% success rate – almost all of the cells have properly accepted the drugs. Healthy cells, on the other hand, demonstrate much fewer side effects than with conventional treatments such as chemotherapy. As Gangopadhyay explains, the nano explosives have some different characteristics than conventional explosives. “In conventional explosives, shock waves are generated during detonation,” she says. “In nanothermites, fast propagating chemical reactions can create shock waves without detonation.” Generating shock waves without detonation is the key to this technology, she says.If everything goes well, the researchers hope to have the device ready to use in two to five years. Besides biomedical applications, the nano explosives could be useful in other areas, such as geology and seismology. Originally, the technology was used in the Army for IED (improvised explosive device) detection, where shock waves sent into the ground could give an image of what lies beneath. More information: S. Apperson, et al. “Generation of fast propagating combustion and shock waves with copper aluminum nanothermite composites.” Applied Physics Letters 91, 243109 (2007).Copyright 2008 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Tests of the nano combustion in the shock tube showed that the nanocomposite could generate combustion waves with velocities ranging from 1500 to 2300 meters per second, which is in the Mach 3 range. Credit: S. Apperson, et al. Shaken and stirred: Scientists capture the deformation effect of shock waves on a material Explore further 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.
Citation: Chinese scientists create metamaterial black hole (2009, October 16) retrieved 18 August 2019 from https://phys.org/news/2009-10-chinese-scientists-metamaterial-black-hole.html (a) A model of black hole composed of a gradient-index metamaterial shell and a lossy dielectric core. (b) Photograph of the fabricated artificial black hole based on metamaterials, which is composed of 60 concentric layers, with the ELC structures in the core layers and the I-shaped structures in the shell layers. Image (c) Qiang Cheng, arXiv paper. Explore further A black hole is a region from which no light can escape. In space, according to relativity theory, black holes are formed when the space becomes distorted by a large mass, preventing light from escaping its gravitational field, but any region from which no light escapes is a black hole.The scientists exploited the special properties of metamaterials to create their mini black hole for microwave frequencies. Metamaterials are a class of ordered composites with properties not usually seen in nature. They are known to distort light, and have already been used to create invisibility cloaks that can steer light around an object. The Chinese scientists used their metamaterial to distort microwaves to the extent that those entering cannot escape.The electromagnetic black hole was built from 60 strips of printed circuit boards coated with a thin layer of copper and arranged in concentric circles. The outer 40 strips form the shell, while the inner strips form the core. Intricate patterns were etched in the copper that alternately resonated and did not resonate at microwave frequency, and which changed progressively from strip to strip. The scientists measured microwaves going into the device, and found none coming out. The microwaves entering the shell are trapped and guided towards the core, where they are absorbed in all directions equally because of the circular symmetry. The energy absorbed is emitted as heat.The current device works only with microwaves, but they are aiming to develop a black hole for visible light next. This is more difficult because the wavelength of visible light is much smaller than microwaves, which means the etched structures must also be much reduced in size. Tie Jun Cui said he expected the visible light black hole to be demonstrated later this year.An artificial visible light black hole could find practical uses in harvesting light for solar cells, and this could mean solar energy could be harvested even in places with diffuse sunlight.More information: An electromagnetic black hole made of metamaterials, arXiv:0910.2159v1 [physics.optics]© 2009 PhysOrg.com Now scientists think you’d be ‘roasted’ in a black hole (PhysOrg.com) — Two physicists in China have used metamaterials to create the first artificial electromagnetic black hole. The scientists, Qiang Cheng and Tie Jun Cui from the Southeast University in Nanjing, China created the tiny black hole in their laboratory, in an experiment that aimed to simulate a black hole. 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.
More information: Genetically encoded fluorescent thermosensors visualize subcellular thermoregulation in living cells, Nature Methods (2013) DOI: 10.1038/nmeth.2690AbstractIn mammals and birds, thermoregulation to conserve body temperature is vital to life. Multiple mechanisms of thermogeneration have been proposed, localized in different subcellular organelles. However, visualizing thermogenesis directly in intact organelles has been challenging. Here we have developed genetically encoded, GFP-based thermosensors (tsGFPs) that enable visualization of thermogenesis in discrete organelles in living cells. In tsGFPs, a tandem formation of coiled-coil structures of the Salmonella thermosensing protein TlpA transmits conformational changes to GFP to convert temperature changes into visible and quantifiable fluorescence changes. Specific targeting of tsGFPs enables visualization of thermogenesis in the mitochondria of brown adipocytes and the endoplasmic reticulum of myotubes. In HeLa cells, tsGFP targeted to mitochondria reveals heterogeneity in thermogenesis that correlates with the electrochemical gradient. Thus, tsGFPs are powerful tools to noninvasively assess thermogenesis in living cells. 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. Measuring temperaure inside cells. Credit: Steven H. Lee © 2013 Phys.org Mitochondrial cooperatives Journal information: Nature Methods The key to building this new sensor is a protein known as TlpA, which is made by Salmonella. The normal operation of TlpA is as an autoregulatory repressor that senses temperature to control transcription. At around 37 degrees C, it undergoes rapid and reversible structural transition to an unfolded monomer. By fusing the fluorophor region of GFP to TlpA, the researchers were able to make the fluorescence spectrum of GFP temperature dependent. The final step was to join the fusion protein to sequences that could target the protein to either the mitochondria, endoplasmic reticulum (ER) or plasma membrane.The researchers were then able to simultaneously image the temperature-sensitive GFP along with the mitochondrial membrane potential indicator dye, JC-1. They found that that elevations in temperature and potential were highly correlated. Perhaps that is not so surprising, but it is the nature and order of these correlations where potency might be derived. They also confirmed this link using another genetically-encoded sensor (ATeam26), along with fluorescence resonance imaging (FRET)to measure ATP. Since ATP is synthesized primarily by an electrochemical pump during oxidative phosphorylation, its production should reflect the mitochondrial proton gradient as seen by JC-1.The characteristics of these complex sensors were vetted by studying the well-known phenomenon of thermogenesis. The researchers looked at brown fat adipocytes, and also avian skeletal muscle, which is the preferred method of heat generation in bird species. The full power of this technology will arguably best be brought to bear when it is applied to the brain. The thermodynamics of spiking neurons has been driven experimentally mainly by rather imprecise external temperature sensors. With a better handle on temperature changes, not just inside and outside axons, but inside the glial cells which myelinate them—and also carry a significant fraction of the spike energy, possibly as phase transitins—a better understand of neural transmission may be had.Where neurons connect, the role of presynaptic mitochondria as transactors of electro-mechanical spike currency into chemo-mechanical vesicle dynamics might now be imaged in telling detail. Similarly on the opposed side of the synapse, where mitochondria are scuttled as a function of minipotential to sop or source calcium, ATP and heat itself, their broader function as hidden communicator of information and power not just at the level of synapse, but cell, may be revealed. Infrared thermography is generally not suitable for imaging fine features in cells. Its spatial resolution is greater than 100μm and it detects only the surface temperature of the object. To measure organelle temperatures, you need a sensor that operates on their scale. A quantum dot or nanodiamond sensor perhaps 100nm wide could be incorporated into a cell by endocytosis, but once inside, it can go anywhere. These sensors can measure intracellular fluctuations of just 0.05 Kelvin (and outside the cell 0.0018), but unless they remain right at heat producing structures in the cell, they will probably only sense uniform thermal background. The reason for this is that not only does any heat generated by these organelles diffuse away rapidly, the organelles themselves like to move. It is worth mentioning that a fascinating paper appeared not long ago on the Arxiv server which attempted to measure how far the effects of the hydrolysis of a single ATP molecule could be felt. The number they came up with is the same size as the sensors we just mentioned, 100nm.The first direct links between organelle function and temperature were made earlier this year by researchers from Japan. They developed a fluorescence lifetime method which used a polymer based thermometer. The temperature resolution they obtained was 0.2 C (apologies for the unit mixing) while the spatial resolution was diffraction limited. These researchers were able to show that the nucleus and centrosome were significantly hotter than other parts of the cell. We generally think of cilia and their associated centrioles as being chemically or molecularlly controlled. Watching their response as a function of temperature may cast their primal role in a new light. While these studies are nice, what sets apart the new research (also done by a Japanese team), is that they could genetically encode a protein-based sensor, target it directly to different organelles like the mitochondria, and then simultaneously measure membrane potential and energy production to correlate temperature increases to the intrinsic function of the organelle. (Phys.org) —If you asked a biologist what any given cell is going to do next, they might ask you first to tell them its electrical potential, oxygenation, pH, osmolarity or glucose concentration. Depending on how finely-scaled your answer might be, they might be able to predict anything from firing an action potential or entering mitosis, to undergoing apoptosis. But what if you knew the subcellular temperature profile in such detail that each mitochondria, centriole and even regions of the endoplasmic reticulum could be read as easily as a mother her child’s fever? That question now drives some of the most exciting research in biology. This year several groups have come up with ingenious thermometric methods ranging from fluorescence lifetime microscopy to exotic diamond nanosensors employing nitrogen vacancy centers. The latest breakthrough, just published in Nature Methods, describes a method that uses a genetically-encoded sensor built from green fluorescent protein (GFP) that is fused to a thermosensing protein borrowed from Salmonella. The researchers used this construct to probe thermogenesis in brown fat mitochondria, and perhaps most astoundingly, were able to correlate temperature with both mitochondrial membrane potential and ATP production. Citation: Mapping subcellular temperature profiles with genetically-encoded thermosensors (2013, October 16) retrieved 18 August 2019 from https://phys.org/news/2013-10-subcellular-temperature-profiles-genetically-encoded-thermosensors.html Explore further
Citation: Genetic study suggests humans may be evolving in a way that prevents alcoholism (2018, February 21) retrieved 18 August 2019 from https://phys.org/news/2018-02-genetic-humans-evolving-alcoholism.html Largest genetic study of mosquitoes reveals spread of insecticide resistance across Africa Humans are, of course, still evolving, which suggests studies looking into the ways we are evolving might be important. In this new effort, Johnson and Voight analyzed genetic data from the over 2,500 people whose DNA ended was used in the 1000 Genomes Project. More specifically, they looked for emerging variants in different population groups that might shed some light on the evolutionary changes that we are currently undergoing. They report that they were able to identify five genetic “hot spots”—resistance to malaria in African populations, an amino acid change in Europeans, two sections of DNA left over from interbreeding with Neanderthals, and finally, an ADH variant.The ADH gene is responsible for inducing production of alcohol dehydrogenase, an enzyme that breaks down alcohol into acetaldehyde, which is then converted to acetate by another process. The researchers note that the variants seem to protect against alcoholism, though how that might happen is still unclear. They theorize that it might break down alcohol faster, causing drinkers to feel sick almost right away—a side-effect that would almost certainly deter drinkers from further consumption. They further theorize that it is possible that over the past 1000 years or so, people, particularly those in their reproductive years, who drank a lot wound up killing themselves off before reproducing—a trend still in evidence today as young people who drink and drive frequently wind up dead before they have a chance to make babies.The researchers report that there was an anomaly in the data, however—ADH variants were not nearly as prevalent in European and American populations as they were in others. They suggest this might have been due to overlooking the markers in the data. © 2018 Phys.org A depiction of the double helical structure of DNA. Its four coding units (A, T, C, G) are color-coded in pink, orange, purple and yellow. Credit: NHGRI Explore further More information: Kelsey Elizabeth Johnson et al. Patterns of shared signatures of recent positive selection across human populations, Nature Ecology & Evolution (2018). DOI: 10.1038/s41559-018-0478-6AbstractSignatures of recent positive selection often overlap across human populations, but the question of how often these overlaps represent a single ancestral event remains unresolved. If a single selective event spread across many populations, the same sweeping haplotype should appear in each population and the selective pressure could be common across populations and environments. Identifying such shared selective events could identify genomic loci and human traits important in recent history across the globe. In addition, genomic annotations that recently became available could help attach these signatures to a potential gene and molecular phenotype selected across populations. Here, we present a catalogue of selective sweeps in humans, and identify those that overlap and share a sweeping haplotype. We connect these sweep overlaps with potential biological mechanisms at several loci, including potential new sites of adaptive introgression, the glycophorin locus associated with malarial resistance and the alcohol dehydrogenase cluster associated with alcohol dependency. Journal information: Nature Ecology & Evolution A pair of researchers with the University of Pennsylvania has found evidence suggesting humans may be evolving in a way that will prevent alcoholism in the future. In their paper published in the journal Nature Ecology & Evolution, Kelsey Elizabeth Johnson and Benjamin Voight describe their study which involved analyzing data from the 1000 Genomes Project looking for emerging gene variants and what they found. 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.
Women’s Moksha, a women’s organisation, has organised Abhoni 2014, the Artisans Crafts Bazaar and Bengali Food Festival to commemorate the 150th birth anniversary of Swami Vivekananda and to celebrate the International Women’s Day. The festival which will go on till 10 March has been organised to promote the cause of women empowerment and the power of youth in our society. The festival which was inaugurated by the Resident Commissioner of West Bengal, Bhaskar Khulbe, looks ahead to promote handloom, handicraft, jute products, food and the varied culture of India. It also aims to provide special emphasis to the tribal and rural segment of the country. A Dog show and mock drill will be demonstration by the National Disaster Response Force team during the festival to make the youth and the common man understand the ground realities of natural calamities and how to cope with such eventualities. Also Read – ‘Playing Jojo was emotionally exhausting’Swami Vivekananda held women in high esteem and appreciated their spirit of service and compassion. For the youth of this country Swami Vivekananda is a role model, an icon of dynamism and vibrancy. He ignited young minds saying ‘my faith is in the younger generation, the modern generation, out of them will come my workers. They will work out the whole problem like lions’. The festival following Vivekananda’s thoughts looks to contribute by creating a platform where youth and women from across the country can come together and share their ideas and bridge the barriers of race, colour, religion and gender. Also Read – Leslie doing new comedy special with NetflixThis festival is a conscious effort by Women’s Moksha to create a credible platform for the women and youth of this country to come together and showcase their culture and tradition. This shall be a stage where women and youth from different states shall get an opportunity to share their culture, tradition, thoughts, skills and talent.Some of the award winning talent of India will also be showcasing their talent during the festival. Some of which include Nagender from A.P. to Naim Khan pottery of Uttar Pradesh. Pattachitra of Orisaa and Jamdani from bengal represented by Akshaye Barik and Khokan Nandy. Abahoni also aims to focus on the culture, tradition and different forms of textiles of Eastern part of India including states like West Bengal, Bihar, Odisha, Jharkhand and Chhatisgarh. The major attraction of the festival is the Artisans Craft Bazaar which will witness participation by artisans from across the country. The objective is to promote rural and tribal handicraft and handloom in India. The artisans and women entrepreneurs shall showcase their work from handloom, handicraft and jute products which in a way will provide them a platform to get a larger audience and market for their work.Other major attraction of the event would be the food festival which will display varied dishes and cuisines from the eastern part of the country. The festival shall witness participants serving diverse varieties and items with several recipes from Bengal, and some exclusive Mughlai dishes. There would also be a special Bengali food stall serving more than 100 nostalgic Bengali dishes.The cultural shows during the festival will witness some renowned local artists from Bengal who would showcase their talent. The fest will also feature different forms of folk dances and music. The festival shall create awareness on the rich and cultural heritage. Such festivals for the youth not only reflect the spirit of friendship but also peace and development. Besides all this, this festival shall provide a nation-wide exposure to the youth for the expression and fulfilment of their cultural talents and aspiration.Women’s Moksha is an organisation dedicated to promote eco- friendly products, principally jute, which have been crafted by the rural section of the Indian Society, thereby empowering them to be self reliant as well as enabling a traditional industry to flourish.WHEN: On till 10 MarchWHERE: Indira Gandhi National Centre For Arts, 3, Rajendra Prasad Road
Kolkata: A jilted lover, under the pretext of having a talk with his girlfriend, slashed her with a razor blade at Princep Ghat on Tuesday evening.The victim, a college student, suffered deep injuries on her throat. She has been under a state of trauma ever since the incident took place. She has been undergoing treatment.The city police have arrested the accused youth Pavan Khan alias Monu. It was learnt that the accused wanted to take revenge on the victim girl as she expressed her desire not to continue the relationship. Also Read – Heavy rain hits traffic, flightsPolice said the victim and the accused, have been seeing each other for some time but the girl wanted to end their relationship for some reasons. She told him about the matter a few days ago. But this did not go down well with the accused and he hatched a plan to give her a lesson. According to the preliminary investigation, police suspect that they started a relation a year ago. For last two months, the duo had engaged in repeated quarrels over various issues. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedAccording to the police, the accused called up the girl on Tuesday afternoon saying that he wanted to settle the matter amicably. She was asked to come to Princep Ghat. He also assured that he would not disturb her further after she meets him there. After the victim arrived the place, a heated altercation broke out between the duo. During the quarrel, the accused suddenly took out a attacked the girl with a razor blade. Hearing the screaming of the victim, locals and on duty police men rushed to the spot and they managed to catch hold of the accused. He was taken to the South Port police station for interrogation. He was later arrested by the police in this connection. The victim girl was taken to a hospital for treatment as she suffered serious injuries on her throat. On the basis of the complaint lodged by the family members of the victim, the police have started a specific case in this regard.
With the escalating conflict between Delhi’s Chief Minister, Arvind Kejriwal and Lieutenant Governor, Najeeb Jung, the peculiarities of the city-state’s governance structure are back in the spotlight. Another battle line bubbling beneath the surface, albeit without the same kind of media glare, is that between the Delhi government and the Municipal Corporation Department (MCD). This too had come to the fore in March, when the three municipal corporations demanded that the Delhi government pay the salaries of the striking