258 research outputs found

    Metabolic and hormonal studies of Type 1 (insulin-dependent) diabetic patients after successful pancreas and kidney transplantation

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    Long-term normalization of glucose metabolism is necessary to prevent or ameliorate diabetic complications. Although pancreatic grafting is able to restore normal blood glucose and glycated haemoglobin, the degree of normalization of the deranged diabetic metabolism after pancreas transplantation is still questionable. Consequently glucose, insulin, C-peptide, glucagon, and pancreatic polypeptide responses to oral glucose and i.v. arginine were measured in 36 Type 1 (insulin-dependent) diabetic recipients of pancreas and kidney allografts and compared to ten healthy control subjects. Despite normal HbA1 (7.2±0.2%; normal <8%) glucose disposal was normal only in 44% and impaired in 56% of the graft recipients. Normalization of glucose tolerance was achieved at the expense of hyperinsulinaemia in 52% of the subjects. C-peptide and glucagon were normal, while pancreatic polypeptide was significantly higher in the graft recipients. Intravenous glucose tolerance (n=21) was normal in 67% and borderline in 23%. Biphasic insulin release was seen in patients with normal glucose tolerance. Glucose tolerance did not deteriorate up to 7 years post-transplant. In addition, stress hormone release (cortisol, growth hormone, prolactin, glucagon, catecholamines) to insulin-induced hypoglycaemia was examined in 20 graft recipients and compared to eight healthy subjects. Reduced blood glucose decline indicates insulin resistance, but glucose recovery was normal, despite markedly reduced catecholamine and glucagon release. These data demonstrate the effectiveness of pancreatic grafting in normalizing glucose metabolism, although hyperinsulinaemia and deranged counterregulatory hormone response are observed frequently

    Large Scale Synthesis of Nanostructured Carbon Ti4O7 Hollow Particles as Efficient Sulfur Host Materials for Multilayer Lithium Sulfur Pouch Cells

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    Applications of advanced cathode materials with well designed chemical components and or optimized nanostructures promoting the sulfur redox kinetics and suppressing the shuttle effect of polysulfides are highly valued. However, in the case of actual lithium sulfur Li amp; 8722;S batteries under practical working conditions, one long term obstacle still exists, which is mainly due to the difficulties in massive synthesis of such nanomaterials with low cost and ease of control on the nanostructure. Herein, we develop a facile synthesis of carbon coated Ti4O7 hollow nanoparticles C amp; 8722;Ti4O7 using spherical polymer electrolyte brush as soft template, which is scalable via utilizing a minipilot reactor. The C amp; 8722;Ti4O7 hollow nanoparticles provide strong chemical adsorption to polysulfides through the large polar surface and additional physical confinement by rich micro amp; mesopores and have successfully been employed as an efficient sulfur host for multilayer pouch cells. Besides, the sluggish kinetics of the sulfur and lithium sulfide redox mechanism can be improved by the highly conductive Ti4O7 via catalyzation of the conversion of polysulfides. Consequently, the C amp; 8722;Ti4O7 based pouch cell endows a high discharge capacity of 1003 amp; 8197;mAh amp; 8201;g amp; 8722;1 at 0.05 amp; 8197;C, a high capacity retention of 83.7 amp; 8201; after 100 amp; 8197;cycles at 0.1 amp; 8197;C, and a high Coulombic efficiency of 97.5 amp; 8201; at the 100th cycle. This work proposes an effective approach to transfer the synthesis of hollow Ti4O7 nanoparticles from lab to large scale production, paving the way to explore a wide range of advanced nanomaterials for multilayer Li amp; 8722;S pouch cell

    Standardized research protocols enable transdisciplinary research of climate variation impacts in corn production systems

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    The important questions about agriculture, climate, and sustainability have become increasingly complex and require a coordinated, multifaceted approach for developing new knowledge and understanding. A multistate, transdisciplinary project was begun in 2011 to study the potential for both mitigation and adaptation of corn-based cropping systems to climate variations. The team is measuring the baseline as well as change of the system\u27s carbon (C), nitrogen (N), and water footprints, crop productivity, and pest pressure in response to existing and novel production practices. Nine states and 11 institutions are participating in the project, necessitating a well thought out approach to coordinating field data collection procedures at 35 research sites. In addition, the collected data must be brought together in a way that can be stored and used by persons not originally involved in the data collection, necessitating robust procedures for linking metadata with the data and clearly delineated rules for use and publication of data from the overall project. In order to improve the ability to compare data across sites and begin to make inferences about soil and cropping system responses to climate across the region, detailed research protocols were developed to standardize the types of measurements taken and the specific details such as depth, time, method, numbers of samples, and minimum data set required from each site. This process required significant time, debate, and commitment of all the investigators involved with field data collection and was also informed by the data needed to run the simulation models and life cycle analyses. Although individual research teams are collecting additional measurements beyond those stated in the standardized protocols, the written protocols are used by the team for the base measurements to be compared across the region. A centralized database was constructed to meet the needs of current researchers on this project as well as for future use for data synthesis and modeling for agricultural, ecosystem, and climate sciences

    Lengthening of maize maturity time is not a widespread climate change adaptation strategy in the US Midwest

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    Increasing temperatures in the US Midwest are projected to reduce maize yields because warmer temperatures hasten reproductive development and, as a result, shorten the grain fill period. However, there is widespread expectation that farmers will mitigate projected yield losses by planting longer season hybrids that lengthen the grain fill period. Here, we ask: (a) how current hybrid maturity length relates to thermal availability of the local climate, and (b) if farmers are shifting to longer season hybrids in response to a warming climate. To address these questions, we used county‐level Pioneer brand hybrid sales (Corteva Agriscience) across 17 years and 650 counties in 10 Midwest states (IA, IL, IN, MI, MN, MO, ND, OH, SD, and WI). Northern counties were shown to select hybrid maturities with growing degree day (GDD°C) requirements more closely related to the environmentally available GDD compared to central and southern counties. This measure, termed “thermal overlap,” ranged from complete 106% in northern counties to a mere 63% in southern counties. The relationship between thermal overlap and latitude was fit using split‐line regression and a breakpoint of 42.8°N was identified. Over the 17‐years, hybrid maturities shortened across the majority of the Midwest with only a minority of counties lengthening in select northern and southern areas. The annual change in maturity ranged from −5.4 to 4.1 GDD year−1 with a median of −0.9 GDD year−1. The shortening of hybrid maturity contrasts with widespread expectations of hybrid maturity aligning with magnitude of warming. Factors other than thermal availability appear to more strongly impact farmer decision‐making such as the benefit of shorter maturity hybrids on grain drying costs, direct delivery to ethanol biorefineries, field operability, labor constraints, and crop genetics availability. Prediction of hybrid choice under future climate scenarios must include climatic factors, physiological‐genetic attributes, socio‐economic, and operational constraints

    Statement in Support of: "Virology under the Microscope-a Call for Rational Discourse"

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    Letter to the Editor. Published 25 April 2023Peter Speck, Jason Mackenzie, Rowena A. Bull, Barry Slobedman, Heidi Drummer, Johanna Fraser, Lara Herrero, Karla Helbig, Sarah Londrigan, Gregory Moseley, Natalie Prow, Grant Hansman, Robert Edwards, Chantelle Ahlenstiel, Allison Abendroth, David Tscharke, Jody Hobson-Peters, Robson Kriiger-Loterio, Rhys Parry, Glenn Marsh, Emma Harding, David A. Jacques, Matthew J. Gartner, Wen Shi Lee, Julie McAuley, Paola Vaz, Frank Sainsbury, Michelle D. Tate, Jane Sinclair, Allison Imrie, Stephen Rawlinson, Andrew Harman, Jillian M. Carr, Ebony A. Monson, Merilyn Hibma, Timothy J.Mahony, Thomas Tu, Robert J. Center, Lok Bahadur Shrestha, Robyn Hall, Morgyn Warner, Vernon Ward, Danielle E. Anderson, Nicholas S. Eyre, Natalie E. Netzler, Alison J. Peel, Peter Revill, Michael Beard, Alistair R. Legione, Alexandra J. Spencer, Adi Idris, Jade Forwood, Subir Sarker, Damian F. J. Purcell, Nathan Bartlett, Joshua M. Deerain, Bruce J. Brew, Sassan Asgari, Helen Farrell, Alexander Khromykh, Daniel Enosi Tuipulotu, David Anderson, Sevim Mese, Yaman Tayyar, Kathryn Edenborough, Jasim Muhammad Uddin, Abrar Hussain, Connor J. I. Daymond, Jacinta Agius, Karyn N. Johnson, Paniz Shirmast, Mahdi Abedinzadeshahri, Robin MacDiarmid, Caroline L. Ashley, Jay Laws, Lucy L. Furfaro, Thomas D. Burton, Stephen M. R. Johnson, Zahra Telikani, Mary Petrone, Justin A. Roby, Carolyn Samer, Andreas Suhrbier, April Van Der Kamp, Anthony Cunningham, Celeste Donato, Jackie Mahar, Wesley D. Black, Subhash Vasudevan, Roman Lenchine, Kirsten Spann, Daniel J. Rawle, Penny Rudd, Jessica Neil, Richard Kingston, Timothy P. Newsome, Ki Wook Kim, Johnson Mak, Kym Lowry, Nathan Bryant, Joanne Meers, Jason A. Roberts, Nigel McMillan, Larisa I. Labzin, Andrii Slonchak, Leon E. Hugo, Bennett Henzeler, Natalee D. Newton, Cassandra T. David, Patrick C. Reading, Camille Esneau, Tatiana Briody, Najla Nasr, Donna McNeale, Brian McSharry, Omid Fakhri, Bethany A. Horsburgh, Grant Logan, Paul Howley, Paul Youn

    Prevalence, conservation and functional analysis of Yersinia and Escherichia CRISPR regions in clinical Pseudomonas aeruginosa isolates

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    Here, we report the characterization of 122 Pseudomonas aeruginosa clinical isolates from three distinct geographical locations: Dartmouth Hitchcock Medical Center in New Hampshire, USA, the Charles T. Campbell Eye Microbiology Lab at the University of Pittsburgh Medical Center, USA, and the Aravind Eye Hospital in Madurai, India. We identified and located clustered regularly interspaced short palindromic repeats (CRISPR) in 45/122 clinical isolates and sequenced these CRISPR, finding that Yersinia subtype CRISPR regions (33 %) were more prevalent than the Escherichia CRISPR region subtype (6 %) in these P. aeruginosa clinical isolates. Further, we observed 132 unique spacers from these 45 CRISPR that are 100 % identical to prophages or sequenced temperate bacteriophage capable of becoming prophages. Most intriguingly, all of these 132 viral spacers matched to temperate bacteriophage/prophages capable of inserting into the host chromosome, but not to extrachromosomally replicating lytic P. aeruginosa bacteriophage. We next assessed the ability of the more prevalent Yersinia subtype CRISPR regions to mediate resistance to bacteriophage infection or lysogeny by deleting the entire CRISPR region from sequenced strain UCBPP-PA14 and six clinical isolates. We found no change in CRISPR-mediated resistance to bacteriophage infection or lysogeny rate even for CRISPR with spacers 100 % identical to a region of the infecting bacteriophage. Lastly, to show these CRISPR and cas genes were expressed and functional, we demonstrated production of small CRISPR RNAs. This work provides both the first examination to our knowledge of CRISPR regions within clinical P. aeruginosa isolates and a collection of defined CRISPR-positive and -negative strains for further CRISPR and cas gene studies
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