Podcasts about photochemical

What is Photochemical Carbon Removal? In this episode of Carbon Removal Newsroom we learn how two professors from the University of Washington went from studying coral on the late Marlon Brando's private island, to developing an energy efficient process that removes carbon dioxide from the ocean. Join co-founders Dr. Alex Gagnon and Dr. Julian Sachs of Banyu Carbon, as they dissect their groundbreaking photochemical process. Learn how carbon dioxide is the most abundant dissolved gas in water, making it a more concentrated source than ambient air. Discover the scalability of photochemical CDR, and why Banyu's been gaining so much momentum lately. Could Banyu's process end up being energy negative? In other words, will it produce more energy than is actually required to remove the carbon? Listen now. *A special Thank You from our guests to the Seeley Family: “Thank you to David Seeley and his father who brought Tetiaroa to our attention in 2014 and encouraged us to take advantage of the pristine coral ecosystem there for our research. The Seeley family generously supported our research and that of several others ever since. A kind, fun, and remarkable family we are grateful to have worked with.” On This Episode Alex Gagnon Julian Sachs Radhika Moolgavkar Resources Banyu Carbon DOE Voucher Program University of Washington marine research on Tetiaroa Activate FellowshipOcean Visions Launchpad  Tetiaroa Society The Brando resort Connect with Nori Nori Nori's X account Nori's other podcast Reversing Climate Change Nori's CDR meme X account --- Send in a voice message: https://podcasters.spotify.com/pod/show/carbonremovalnewsroom/message Support this podcast: https://podcasters.spotify.com/pod/show/carbonremovalnewsroom/support

With four seasons under our belt, we've heard some amazing stories about how our guests have found, or often “stumbled” into, their careers in science. We've also had many conversations where past guests have passionately discussed the importance of their early career teachers as well as what teaching does for them in their current careers. This conversation is squarely centered on these two topics, with a good dose of photochemistry mixed in too. We meet Dr. Izzy Lamb, Assistant Professor at Fort Lewis College, which is a small liberal arts school in Colorado with a primarily undergraduate student population. Izzy is entertainingly forthright in admitting that he's often a bit surprised by his success in chemistry given that he was failing the topic in high school and was later accepted to only one of the six graduate programs he applied to. However, our conversation quickly uncovers why Izzy has been successful in what matters most to him—exploring photochemistry and training the next generation of chemists. Join us for this engaging look at how Izzy has built a thriving career in chemistry through perseverance, passion, and knowing what matters most to him. We learn about his career in photocatalysis and how he's now adapting his research to better fit the resources and undergraduate students where he's now working. A passion for teaching students in a way that gets them thinking and equipped to solve real-world problems is his priority, and we learn how he's using a passion for understanding quantum yields of photochemical reactions to help inform more sustainable ways of doing chemistry.Related episodes: Season 1, Ep.2: Reinventing plastics, one reaction at a time Season 3, Ep.1: Fuel the world with light -  the wonders of nano-magnesiumSeason 3, Ep.9: Energy harvesting and self-sustainable greenhousesBonus content!Access bonus content curated by this episode's guest by visiting www.thermofisher.com/chemistry-podcast for links to recent publications, podcasts, books, videos and more.View the video of this episode on www.thermofisher.com/chemistry-podcast.A free thank you gift for our listeners! Visit the episode website and request your free Bringing Chemistry to Life t shirt.Use Podcast Code:  Ba++ery in January 2024 or liV4chem in February We read every email so please share your questions and feedback with us! Email helloBCTL@thermofisher.com About Your HostPaolo Braiuca grew up in the North-East of Italy and holds a PhD in Pharmaceutical Sciences from nearby esteemed University of Trieste, Italy. He developed expertise in biocatalysis during his years of post-doctoral research in Italy and the UK, where he co-founded a startup company. With this new venture, Paolo's career shifted from R&D to business development, taking on roles in commercial, product management, and marketing. He has worked in the specialty chemicals, biotechnology, and pharmaceutical markets in Germany and the UK, where he presently resides. He is currently the Director of Global Market Development in the Laboratory Chemicals Division at Thermo Fisher Scientific™ which put him in the host chair of the Bringing Chemistry to Life podcast. A busy father of four, in what little free time he has, you'll find him inventing electronic devices with the help of his loyal 3D-printer and soldering iron. And if you ask him, he'll call himself a “maker” at heart.

ทำความรู้จักกับ วิตามินอี พร้อมรู้ถึงคุณประโยชน์มากมายของวิตามินอี อาหารที่อุดมไปด้วยของวิตามินอี และยีนที่เกี่ยวข้องกับวิตามินอี

A photochemical model of Triton's atmosphere with an uncertainty propagation study by B. Benne et al. on Monday 12 September Triton is the largest satellite of Neptune and probably a Kuiper Belt Object that was captured by the planet. It has a tenuous nitrogen atmosphere similar to the one of Pluto and may be an ocean world. The Neptunian system has only been visited by Voyager 2 in 1989. Over the last few years, the demand for a new mission to the Ice Giants and their systems has increased so that a theoretical basis to prepare for such a mission is important. We aim to develop a photochemical model of Triton's atmosphere with an up-to-date chemical scheme, as previous photochemical models date back to the post-flyby years. This is done to better understand the mechanisms governing Triton's atmospheric chemistry and highlight the critical parameters having a significant impact on the atmospheric composition. We also study model uncertainties to find what chemical studies are necessary to improve the modeling of Triton's atmosphere. We adapted a model of Titan's atmosphere to Triton's conditions. We first used Titan's chemical scheme before updating it to better model Triton's atmosphere. Once the nominal results were obtained, we studied model uncertainties with a Monte-Carlo procedure. Then, we performed global sensitivity analyzes to identify the reactions responsible for model uncertainties. With the nominal results, we determined the composition of Triton's atmosphere and studied the main chemical processes. We highlighted key chemical reactions that are the most important for the overall chemistry. We also identified some key parameters having a significant impact on the results. Uncertainties are large for most of the main atmospheric species as the atmospheric temperature is very low. We identified key uncertainty reactions that have the largest impact on the results uncertainties. These reactions must be studied in priority in order to improve the significance of our results. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.04324v1

A photochemical model of Triton's atmosphere with an uncertainty propagation study by B. Benne et al. on Monday 12 September Triton is the largest satellite of Neptune and probably a Kuiper Belt Object that was captured by the planet. It has a tenuous nitrogen atmosphere similar to the one of Pluto and may be an ocean world. The Neptunian system has only been visited by Voyager 2 in 1989. Over the last few years, the demand for a new mission to the Ice Giants and their systems has increased so that a theoretical basis to prepare for such a mission is important. We aim to develop a photochemical model of Triton's atmosphere with an up-to-date chemical scheme, as previous photochemical models date back to the post-flyby years. This is done to better understand the mechanisms governing Triton's atmospheric chemistry and highlight the critical parameters having a significant impact on the atmospheric composition. We also study model uncertainties to find what chemical studies are necessary to improve the modeling of Triton's atmosphere. We adapted a model of Titan's atmosphere to Triton's conditions. We first used Titan's chemical scheme before updating it to better model Triton's atmosphere. Once the nominal results were obtained, we studied model uncertainties with a Monte-Carlo procedure. Then, we performed global sensitivity analyzes to identify the reactions responsible for model uncertainties. With the nominal results, we determined the composition of Triton's atmosphere and studied the main chemical processes. We highlighted key chemical reactions that are the most important for the overall chemistry. We also identified some key parameters having a significant impact on the results. Uncertainties are large for most of the main atmospheric species as the atmospheric temperature is very low. We identified key uncertainty reactions that have the largest impact on the results uncertainties. These reactions must be studied in priority in order to improve the significance of our results. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.04324v1

A photochemical model of Triton's atmosphere with an uncertainty propagation study by B. Benne et al. on Monday 12 September Triton is the largest satellite of Neptune and probably a Kuiper Belt Object that was captured by the planet. It has a tenuous nitrogen atmosphere similar to the one of Pluto and may be an ocean world. The Neptunian system has only been visited by Voyager 2 in 1989. Over the last few years, the demand for a new mission to the Ice Giants and their systems has increased so that a theoretical basis to prepare for such a mission is important. We aim to develop a photochemical model of Triton's atmosphere with an up-to-date chemical scheme, as previous photochemical models date back to the post-flyby years. This is done to better understand the mechanisms governing Triton's atmospheric chemistry and highlight the critical parameters having a significant impact on the atmospheric composition. We also study model uncertainties to find what chemical studies are necessary to improve the modeling of Triton's atmosphere. We adapted a model of Titan's atmosphere to Triton's conditions. We first used Titan's chemical scheme before updating it to better model Triton's atmosphere. Once the nominal results were obtained, we studied model uncertainties with a Monte-Carlo procedure. Then, we performed global sensitivity analyzes to identify the reactions responsible for model uncertainties. With the nominal results, we determined the composition of Triton's atmosphere and studied the main chemical processes. We highlighted key chemical reactions that are the most important for the overall chemistry. We also identified some key parameters having a significant impact on the results. Uncertainties are large for most of the main atmospheric species as the atmospheric temperature is very low. We identified key uncertainty reactions that have the largest impact on the results uncertainties. These reactions must be studied in priority in order to improve the significance of our results. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.04324v1

A photochemical model of Triton's atmosphere with an uncertainty propagation study by B. Benne et al. on Monday 12 September Triton is the largest satellite of Neptune and probably a Kuiper Belt Object that was captured by the planet. It has a tenuous nitrogen atmosphere similar to the one of Pluto and may be an ocean world. The Neptunian system has only been visited by Voyager 2 in 1989. Over the last few years, the demand for a new mission to the Ice Giants and their systems has increased so that a theoretical basis to prepare for such a mission is important. We aim to develop a photochemical model of Triton's atmosphere with an up-to-date chemical scheme, as previous photochemical models date back to the post-flyby years. This is done to better understand the mechanisms governing Triton's atmospheric chemistry and highlight the critical parameters having a significant impact on the atmospheric composition. We also study model uncertainties to find what chemical studies are necessary to improve the modeling of Triton's atmosphere. We adapted a model of Titan's atmosphere to Triton's conditions. We first used Titan's chemical scheme before updating it to better model Triton's atmosphere. Once the nominal results were obtained, we studied model uncertainties with a Monte-Carlo procedure. Then, we performed global sensitivity analyzes to identify the reactions responsible for model uncertainties. With the nominal results, we determined the composition of Triton's atmosphere and studied the main chemical processes. We highlighted key chemical reactions that are the most important for the overall chemistry. We also identified some key parameters having a significant impact on the results. Uncertainties are large for most of the main atmospheric species as the atmospheric temperature is very low. We identified key uncertainty reactions that have the largest impact on the results uncertainties. These reactions must be studied in priority in order to improve the significance of our results. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.04324v1

ABOUT TODAY's EPISODE Today we look at everything from polypodium leucotomos to UPF rated clothing. What else is out there for besides sunscreen for sun protection? Enjoy the episode! SUPPORT! Thank you SO much for your constant support. It means the world to me. If you are wondering how you can support, please see below Share share share to the ends of the world: You can share this podcast to as many people as you know and love. You does not love a fun podcast about hair and skin? See links for that here https://linktr.ee/ChiomaAgha Support financially: https://anchor.fm/chioma-agha Download: Do you know that you can download any episode? Take me (well my voice, LOL) anywhere you are. Just click on download, and voila! Listen: Errmmm listen listen and listen again. You can listen one zillion uncountable billion times. LOL. Listen to the Ads ooooooo. T for Tenks REFERENCES 1. 1. Serpone, Nick. “Sunscreens and their usefulness: have we made any progress in the last two decades?.” Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology vol. 20,2 (2021): 189-244. doi:10.1007/s43630-021-00013-1 2. 1. Katja Žmitek, Janko Žmitek, Mirjam Rogl Butina, Hristo Hristov, Tina Pogačnik, Igor Pravst, Lee, Erica H et al. “Dietary lutein reduces ultraviolet radiation-induced inflammation and immunosuppression.” The Journal of investigative dermatology vol. 122,2 (2004): 510-7. doi:10.1046/j.0022-202X.2004.22227. 3. Christophe Antille, Christian Tran, Olivier Sorg, Pierre Carraux, Liliane Didierjean, Jean-Hilaire Saurat. "Vitamin A Exerts a Photoprotective Action in Skin by Absorbing Ultraviolet B Radiation". Journal of Investigative Dermatology, Volume 121, Issue 5, 2003, Pages 1163-1167,ISSN 0022-202X. doi.org/10.1046/j.1523-1747.2003.12519. 4. Caccialanza, M et al. “Oral polypodium leucotomos extract photoprotective activity in 57 patients with idiopathic photodermatoses.” Giornale italiano di dermatologia e venereologia : organo ufficiale, Societa italiana di dermatologia e sifilografia vol. 146,2 (2011): 85-7. 5. Berman, Brian et al. “Polypodium Leucotomos--An Overview of Basic Investigative Findings.” Journal of drugs in dermatology : JDD vol. 15,2 (2016): 224-8. 6. Dietary lutein supplementation protects against ultraviolet-radiation-induced erythema: Results of a randomized double-blind placebo-controlled study. Journal of Functional Foods. Volume 75, 2020, 104265, ISSN 1756-4646. Disclaimer The information provided on this podcast, including but not limited to, text, graphics, are for informational purposes only and does not serve as a diagnosis, treatment or substitute for medical advice. Always seek the advice of a qualified health care professional for any medical condition you may be experiencing. --- This episode is sponsored by · Anchor: The easiest way to make a podcast. https://anchor.fm/app Support this podcast: https://anchor.fm/chioma-agha/support

[Dr.Amp Podcast ตอนพิเศษ] เคล็ด(ไม่)ลับ เพื่อสุขภาพดีของหมอแอมป์ EP.3 เรื่อง การดูแลผิวพรรณของหมอแอมป์

ABOUT TODAY's EPISODE How you like the title, huh? Oscars loading... Hi guys! In today's episode, we look at ways we can protect ourselves from harmful UV rays. Did you know you can use other things beside sunscreen? Well the tea is waiting for you in this episode. I hope you enjoy! SUPPORT! Thank you SO much for your constant support. It means the world to me. If you are wondering how you can support, please see below Share share share to the ends of the world: You can share this podcast to as many people as you know and love. You does not love a fun podcast about hair and skin? See links for that here https://linktr.ee/ChiomaAgha Support financially: https://anchor.fm/chioma-agha Download: Do you know that you can download any episode? Take me (well my voice, LOL) anywhere you are. Just click on download, and voila! Listen: Errmmm listen listen and listen again. You can listen one zillion uncountable billion times. LOL. Listen to the Ads ooooooo. T for Tenks REFERENCES 1. 1. Serpone, Nick. “Sunscreens and their usefulness: have we made any progress in the last two decades?.” Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology vol. 20,2 (2021): 189-244. doi:10.1007/s43630-021-00013-1 2. 1. Katja Žmitek, Janko Žmitek, Mirjam Rogl Butina, Hristo Hristov, Tina Pogačnik, Igor Pravst, Lee, Erica H et al. “Dietary lutein reduces ultraviolet radiation-induced inflammation and immunosuppression.” The Journal of investigative dermatology vol. 122,2 (2004): 510-7. doi:10.1046/j.0022-202X.2004.22227. 3. Christophe Antille, Christian Tran, Olivier Sorg, Pierre Carraux, Liliane Didierjean, Jean-Hilaire Saurat. "Vitamin A Exerts a Photoprotective Action in Skin by Absorbing Ultraviolet B Radiation". Journal of Investigative Dermatology, Volume 121, Issue 5, 2003, Pages 1163-1167,ISSN 0022-202X. doi.org/10.1046/j.1523-1747.2003.12519. Disclaimer The information provided on this podcast, including but not limited to, text, graphics, are for informational purposes only and does not serve as a diagnosis, treatment or substitute for medical advice. Always seek the advice of a qualified health care professional for any medical condition you may be experiencing. --- This episode is sponsored by · Anchor: The easiest way to make a podcast. https://anchor.fm/app Support this podcast: https://anchor.fm/chioma-agha/support

How does drought influence the photochemical performance of reproductive structures of native and exotic bunchgrasses of the Great Basin? You can read the blog post at https://www.botany.one/2022/02/photochemical-performance-of-bunchgrass-reproductive-structures/ You can read the original research at https://doi.org/10.1093/aobpla/plab076

Kim Knowles has been writing and teaching about experimental film for over 15 years and currently lectures in Alternative and Experimental Film at Aberystwyth University in Wales. She curates the Black Box strand of the Edinburgh International Film Festival. A programme described as “Daring, challenging, uncompromising and thought-provoking” with short and feature-length experimental and artists’ films from around the world. In EP.27 we discuss her journey into experimental film and the screening when she fell in love with the experience of watching 16mm film projected in a cinema. We talk about her militant defence of photochemical film, materialist film, her experience attending The Independent Imaging Retreat (Film Farm) in Canada and lecturing in Alternative and Experimental Film at Aberystwyth University in Wales. Goto www.intothemothlight.com for images and links to key artists, works and texts discussed in the interview.

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.19.345652v1?rss=1 Authors: Cheng, Z., Mobley, C., Misra, S. K., Sharp, J. S. Abstract: The analysis of membrane protein topography using fast photochemical oxidation of protein (FPOP) has been reported in recent years, but still underrepresented in literature. Based on the hydroxyl radical reactivity of lipids and other amphiphiles, it is believed that the membrane environment acts as a hydroxyl radical scavenger decreasing effective hydroxyl radical doses and resulting in less observed oxidation of proteins. Here, we investigated the effect of bulk hydroxyl radical scavenging in FPOP using both isolated cellular membranes as well as detergent micelles. We found no significant change in radical scavenging activity upon the addition of disrupted cellular membranes with the membrane concentration in the range of 0-25600 cell/L using an inline radical dosimeter. We confirmed the non-scavenging nature of the membrane with the FPOP results of a soluble model protein in the presence of cell membranes, which showed no significant difference in oxidation with or without membranes. The use of detergents revealed that, while soluble detergent below the critical micelle concentration acts as a potent hydroxyl radical scavenger as expected, additional detergent has little to no hydroxyl radical scavenging effect once the critical micelle concentration is reached. These results suggest that any scavenging effect of membranes or organized amphiphilic membrane mimetics in FPOP experiments are not due to bulk hydroxyl radical scavenging, but may be due to a localized scavenging phenomenon. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.16.342477v1?rss=1 Authors: Lanyon-Hogg, T., Ritzefeld, M., Zhang, L., Pogranyi, B., Mondal, M., Johnston, C. D., Coupland, C. E., Sefer, L., Andrei, S. A., Newington, J., Magee, A. I., Siebold, C., Tate, E. W. Abstract: The mammalian membrane-bound O-acyltransferase (MBOAT) superfamily is involved in biological processes including growth, development and appetite sensing. MBOATs are attractive drug targets in cancer and obesity; however, information on the binding site and molecular mechanisms underlying small-molecule inhibition is elusive. This study reports development of a photochemical probe to interrogate the small-molecule binding site in the human MBOAT Hedgehog acyltransferase (HHAT) based on HHAT inhibitor RUSKI-201. Structure-activity relationship investigation identified the improved enantiomeric inhibitor IMP 1575, which is the most potent HHAT inhibitor reported to-date, and guided rational design of a photocrosslinking probe that maintained HHAT-inhibitory potency. Photocrosslinking and proteomic sequencing of HHAT delivered identification of the first small-molecule binding site in a mammalian MBOAT. Topology and homology data suggested a potential mechanism for HHAT inhibition which was confirmed via kinetic analysis. Our results provide an optimal HHAT inhibitor IMP-1575 (Ki = 38 nM) and a strategy for mapping of interaction sites in MBOATs. Copy rights belong to original authors. Visit the link for more info

รายการ Dr.Amp Podcast เรื่องเล่าสุขภาพดี กับ หมอแอมป์ ตอน "5 สุดยอดวิตามินบำรุงผิว ตอนที่ 1" โดย นพ. ตนุพล วิรุฬหการุญ -ประธานเจ้าหน้าที่ปฏิบัติการ และ ผู้อำนวยการ BDMS Welness Clinic -ผู้อำนวยการ RoyalLife โรงพยาบาลกรุงเทพ -นายกสมาคมแพทย์ฟื้นฟูสุขภาพและส่งเสริมการศึกษาโรคอ้วน กรุงเทพ (BARSO)

Podcast: Download Subscribe: Apple Podcasts | Spotify | Stitcher | Google Play | RSS THIS WEEK: Van and Sven are left to their own devices to examine the unfortunate Baron Tusk and all the unpleasantness within his arc. In this episode, Sven's preferences are outted; props are broken; patience is tested; Sven's vision problems count as weighted armor; the two northern-living members of the podcast get real picky about snow effects; Van takes a trip down Rider's shared timeline; a lot of really great questions are asked; and we are very tired of saying the word "doovoo". TOPICS:* Kamen Rider V3 (1973) 31-35* Skull Warthog, Onibi Walrus, Snow Wolf, Primordial Tiger, Vampiric Mammoth* Baron Tusk, the "Doovoo" witch doctor* Skeleton Warriors!* A tangent on voodoo zombies* Tuxedos...?* Doppleganger plots!* Ken Sakuma as a discount Taki* Ghostlight effects* Weirdly poignant death scenes* Photochemical smog* Junko's questionable friend circle* Continuity re: weaknesses* The Double Riders return!* Timeline trouble with the Primordial Tiger* Combination attacks!* Particularly gruesome practical effects* A chain of incredibly deadly ruses* The good and the bad (mostly bad) of Baron Tusk* Listener questions: Rider professions MUSIC:* “Fight! Seven Riders!! Showa Rider Taisen” – Kamen Rider x Kamen Rider Fourze & OOO: Movie War Megamax* Hiroshi Miyauchi – “Fight! Kamen Rider V3”* Jin, feat. Shoichi Taguchi - "Kagerou Days" - Mekakucity Actors* Ichiro Mizuki, feat. the Columbia Yurikago Children’s Choir – “Song of the Kamen Rider Scouts” NEXT WEEK: The... uh... end... of Inazuman. Twitter | Tumblr | Patreon | Ko-Fi

Meags loves photo booths. Final song: Laisse Autant Le Vent Tout Emporter by Les Breastfeeders

In this paper we investigate the photochromic ring-opening reaction of 2,2-diphenyl-5,6-benzo(2H)-chromene. In particular, we study the uncertainties and contradictions in various published reaction models using a combination of transient absorption and fluorescence spectroscopy with femtosecond time resolution. We propose a simplified reaction scheme which is in good agreement with theoretical studies. Here, photoexcitation populates a Franck-Condon state, whose fast vibrational wave packet motion, vibrational relaxation, bond-alternation and/or solvent rearrangement processes occur on the sub-picosecond timescale. Our data suggest that the resulting excited state minimum with picosecond lifetime still features structural characteristics of the closed form. Subsequently, the ring-opened photoproducts are formed in a concerted step from the excited state. The velocity of the photoreaction hence only depends on the time that the molecule needs to reach the transition region between the ground and excited states where the crucial bond breakage occurs.

Personalized Cancer Medicine 1

There are two ozone problems in the atmosphere. Tropospheric ozone in the form of photochemical smog is sometimes dangerously high whereas stratospheric ozone concentration is sometimes dangerously low. Photochemical smog is created through chemical reactions between UV radiation from the run and nitrogen oxides that are emitted from automobiles. High concentrations of tropospheric ozone are dangerous because of the damage ozone can cause to a person’s airway if it is inhaled. The EPA has specified limits of ozone concentration but several counties in the USA exceed these limits. The primary air pollutants from which ozone is created have a peak concentration twice a day typically, which is associated with rush hour times during the day. Complete course materials are available at the Open Yale Courses website: http://oyc.yale.edu This course was recorded in Fall 2011.

Senior lecturer Rod Barratt explains the context of case studies chosen for this album.

Transcript -- How to clean the air. Demonstration of methods used to remove pollutants from the air, including factory emissions.

How to clean the air. Demonstration of methods used to remove pollutants from the air, including factory emissions.

How to clean the air. Demonstration of methods used to remove pollutants from the air, including factory emissions.

Transcript -- How to clean the air. Demonstration of methods used to remove pollutants from the air, including factory emissions.

Senior lecturer Rod Barratt explains the context of case studies chosen for this album.

Transcript -- How to clean the air. Demonstration of methods used to remove pollutants from the air, including factory emissions.

How to clean the air. Demonstration of methods used to remove pollutants from the air, including factory emissions.

How to clean the air. Demonstration of methods used to remove pollutants from the air, including factory emissions.

Transcript -- How to clean the air. Demonstration of methods used to remove pollutants from the air, including factory emissions.

Gene therapy is a very promising approach to treat or to prevent diseases. However, progress in this field is hindered by lack of suitable vectors. Current research focuses on the development of novel nonviral biodegradable gene carriers with improved gene transfer activity and low toxicity. In the course of this thesis, a library of degradable DNA compacting domains based on oligomerized polyamines was synthesized and analyzed. Degradation of the originated polymers was either based on site-specific reductive cleavage of disulfide bonds or on time-dependent ester/amide hydrolysis. DNA binding activity, polyplex stability, transfection efficiency, toxicity, and hemocompatibility studies were performed in order to identify promising candidates. Some of the novel gene carriers, especially the degradable oligoethylenimine (OEI) derivatives were successfully applied for in vitro transfection and could easily compete with the current ‘golden standard’ linear polyethylenimine with an average Mw of 22 kDa (PEI22lin). Furthermore, screening results revealed critical structure activity relationships which were very helpful for improving the polymer design. According to transfection and biocompatibility results, efficiency and toxicity correlated to some degree. Polymers with an overall high charge density and a high molecular weight like OEI-HD-1 provided polyplex stability and formed small uniform particles. On the other hand these polymers tended to induce erythrocyte aggregation and exhibited a pronounced cytotoxicity when applied at high concentrations. Polycation with a lower molecular weight (~ 10 kDa) like e.g. OEI-IP-1 were essentially nontoxic, but had to be applied at high concentrations in order to achieve efficient gene transfer. Intrinsic membrane activity of certain polymers could damage cellular membranes but may also trigger endosomal release and therefore boost transfection activity. Crosslinking of OEI 800 with 1,6-hexanedioldiacrylate resulted in highly efficient degradable polycations. Different reaction temperatures during OEI-HD-1 synthesis had a strong impact on molecular weight and the ester/amide ratio. Despite structural differences, both OEI-HD-1 (synthesized at 60°C) and lt-OEI-HD-1 (synthesized at 20°C) possessed equal gene transfer activity as the ‘golden standard’ PEI22lin when applied at their optimal polymer/DNA-ratio (w/w). It was important to note that lt-OEI-HD-1, the LMW-derivative which is predominantly based on ester linkages, was significantly less toxic than its HMW amide-linked counterpart. OEI-HD displayed a very promising basis for the development of further powerful gene carriers. A two-step synthesis protocol was established in order to generate OEI-HD cores bearing excessive linker which could be subsequently modified with various functionalities like spermine. OEI-HD-Sper pseudo-dendrimers were characterized by a pronounced intrinsic membrane activity and possess high transfection efficiency. Since current nonviral vectors are still very inefficient as compared to their viral competitors, natural viruses present an ideal example educating us how to further optimize polycationic gene carriers in terms of specific cell-targeting and improved endosomal release. Modification of polyplexes towards a “smart” virus-like system was achieved in the following way. Degradable DNA compacting domains (OEI-HD-1) were utilized for complex formation. Furthermore, epidermal growth factor (EGF) was incorporated as targeting ligand into OEI-HD-1 polyplexes and thus allowed cell-specific cellular uptake via the EGF receptor (EGFR). Gene transfer potential of EGFR-targeted degradable polyplexes was further improved by applying technologies which promoted the endosomal release of endocytosed particles. Photochemical intracellular release (PCI) is based on accumulation of amphiphilic photosensitizers (PS) in endosomal membranes. Illumination of PS pre-treated transfected cells results in activation of the PS and subsequent light-induced rupture of endocytic vesicles. Combination of biological (EGFR) and physical (PCI) targeting greatly enhanced reporter gene delivery mediated by OEI-HD-1 polyplexes. Finally, the incorporation of membrane active melittin derivatives into EGF/OEI-HD-1 polyplexes was the first example of a biodegradable synthetic virus for gene delivery.

Tue, 1 Jan 1991 12:00:00 +0100 https://epub.ub.uni-muenchen.de/3579/1/3579.pdf Oesterhelt, Dieter; Zinth, Wolfgang ddc:530, Physik

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/2338/ http://epub.ub.uni-muenchen.de/2338/1/2338.pdf Struck, A.; Cmiel, Edmund; Schneider, Siegfried; Scheer, Hugo Struck, A.; Cmiel, Edmund; Schneider, Siegfried und Scheer, Hugo (1990): Photochemical ring-opening in 20-chloro-chlorophylls. In: Baltschewsky, M. (Hrsg.), Current research in photosynthesis. Bd. 3, Kluwer: Dordrecht u.a., pp. 691-694. Biologie

Irradiation of 20-chloro-chlorophylls of the a-type with visible light produces long-wavelength shifted photoproducts, which transform in the dark to linear tetrapyrroles (bile pigments). The possible significance for chlorophyll degradation is discussed.

The first steps in the photochemistry of bacteriorhodopsin (BR) are investigated with light pulses of 160 fs duration. Four samples are studied: (i) the purple membrane, (ii) deuterated purple membrane, (iii) BR trimers and (iv) BR monomers. In all samples the first intermediate J is formed within 430±50 fs. No isotope effect is observed in the formation of J upon deuteration, in contrast to previous reports with much higher excitation energies. Thus proton movement to or from the retinal Schiff's base is not relevant during the first step. Comparing the data for trimeric and monomeric BR suggests an upper limit of 50 fs for the transfer of excitation energy from the excitonically coupled trimer to a single retinal chromophore.

The early events in halorhodopsin after light excitation are studied with picosecond time resolution. Absorption and fluorescence measurements show that the electronically excited state of the incorporated retinal has a lifetime of 5 ps. Within that time a red-shifted photoproduct is formed that remains stable for at least 2 ns.

Crystallized reaction centers from Rhodopseudomonas viridis (i) are photochemically active with electron transfer from the special pair to the quinones, (ii) show dichroism giving valuable information on the orientation of the different chromophores and (iii) allow chemical treatment in the crystalline phase.

Thu, 1 Jan 1981 12:00:00 +0100 http://epub.ub.uni-muenchen.de/2829/ http://epub.ub.uni-muenchen.de/2829/1/044.pdf Friedrich, J.; Scheer, Hugo; Zickendraht-Wendelstadt, Barbara; Haarer, D. Friedrich, J.; Scheer, Hugo; Zickendraht-Wendelstadt, Barbara und Haarer, D. (1981): ENERGY TRANSFER IN PHYCOBILIPROTEINS AS STUDIED BY PHOTOCHEMICAL HOLE BURNING. In: Journal of Luminescence, Vol. 24/25: pp. 815-818. Bi

We have shown that both the native C-phycocyanin and its corresponding free biline chromophore undergo reversible, low-temperature photochemistry. We attribute this photochemistry to reversible proton-transfer processes and utilize the observed photoreaction for photochemical hole burning (PHB). Using narrow-band PHB experiments, we have been able to perform high-resolution optical studies and show that the protein-chromophore assembly forms a very rigid structure. The results lead to the conclusion that the light-induced proton transfer occurs most probably in the triplet state.

Thu, 1 Jan 1981 12:00:00 +0100 http://epub.ub.uni-muenchen.de/2831/ http://epub.ub.uni-muenchen.de/2831/1/046.pdf Friedrich, J.; Scheer, Hugo; Zickendraht-Wendelstadt, Barbara; Haarer, D. Friedrich, J.; Scheer, Hugo; Zickendraht-Wendelstadt, Barbara und Haarer, D. (1981): Photochemical hole burning. A means to observe high resolution optical structures in phycoerythrin. In: Journal of Chemical Physics, Vol. 74: pp. 2260-2266. Biologie 0

Sat, 1 Jan 1977 12:00:00 +0100 http://epub.ub.uni-muenchen.de/2575/ http://epub.ub.uni-muenchen.de/2575/1/2575.pdf Scheer, Hugo; Linsenmeier, U.; Krauss, Corinna Scheer, Hugo; Linsenmeier, U. und Krauss, Corinna (1977): Chemical and photochemical oxygenation of a phytochrome Pr chromophore model pigment to purpurins. In: Hoppe-Seyler's Zeitschrift für physiologische Chemie, Vol. 358: pp. 185-196.

A laser uv-microbeam with a wavelength of 2573 Å having a minimum spot diameter of approx 0.5 μm was used to microirradiate interphase cells of a V-79 subline of Chinese hamster cells. The incident energy necessary to induce a significant decrease of proliferation was 30 to 60 times larger after microirradiation of cytoplasm as compared with microirradiation of nucleoplasm. The mean value of relative cell numbers 40 hr after irradiation as a function of incident energy did not differ whether the cells were microirradiated lying singly or together in small groups. Analysis of individual growth curves of singly lying cells microirradiated in the nucleoplasm with the same energy showed heterogeneous reactions. The incident energy per cell compatible with proliferation of about 50% of the cells after microirradiation of nucleoplasm was approx. 2× 10sup-3/sup ergs. From this value it is suggested that the energy density within the focus was in the region of several thousand ergs per square millimeter. Photochemical effects are thought to be the cause of growth disturbance, while thermal effects are excluded.