Molecular assessment of complex microbial communities degrading long chain fatty acids in methanogenic bioreactors

Microbial diversity of anaerobic sludge after extended contact with long chain fatty acids (LCFA) was studied using molecular approaches. Samples containing high amounts of accumulated LCFA were obtained after continuous loading of two bioreactors with oleate or with palmitate. These sludge samples were then incubated in batch assays to allow degradation of the biomass-associated LCFA. In addition, sludge used as inoculum for the reactors was also characterized. Predominant phylotypes of the different samples were monitored using denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA gene fragments. Fingerprinting analysis showed changes in bacterial and archaeal communities during LCFA accumulation and degradation. Full-length 16S rRNA gene sequences of 22 clones, representing the predominant bacteria and archaea, were determined. Most bacterial clones (80%) clustered within the Clostridiaceae. Two major groups of methanogens were identified: hydrogen- and formate-utilizing organisms, closely related to Methanobacterium, and acetoclastic organisms closely related to Methanosaeta and Methanosarcina. Quantification by FISH and real-time PCR showed that the relative abundance of archaea increased during degradation of biomass-accumulated LCFA. These results provide insight into the importance and dynamics of balanced communities of bacteria and methanogens in LCFAaccumulation/ degradation cycles.Fundação para a Ciência e a Tecnologia (FCT); Fundo Social Europeu (FSE)

4D Flow cardiovascular magnetic resonance consensus statement: 2023 update

Hemodynamic assessment is an integral part of the diagnosis and management of cardiovascular disease. Four-dimensional cardiovascular magnetic resonance flow imaging (4D Flow CMR) allows comprehensive and accurate assessment of flow in a single acquisition. This consensus paper is an update from the 2015 '4D Flow CMR Consensus Statement'. We elaborate on 4D Flow CMR sequence options and imaging considerations. The document aims to assist centers starting out with 4D Flow CMR of the heart and great vessels with advice on acquisition parameters, post-processing workflows and integration into clinical practice. Furthermore, we define minimum quality assurance and validation standards for clinical centers. We also address the challenges faced in quality assurance and validation in the research setting. We also include a checklist for recommended publication standards, specifically for 4D Flow CMR. Finally, we discuss the current limitations and the future of 4D Flow CMR. This updated consensus paper will further facilitate widespread adoption of 4D Flow CMR in the clinical workflow across the globe and aid consistently high-quality publication standards

UBR2 of the N-End Rule Pathway Is Required for Chromosome Stability via Histone Ubiquitylation in Spermatocytes and Somatic Cells

The N-end rule pathway is a proteolytic system in which its recognition components (N-recognins) recognize destabilizing N-terminal residues of short-lived proteins as an essential element of specific degrons, called N-degrons. The RING E3 ligases UBR2 and UBR1 are major N-recognins that share size (200 kDa), conserved domains and substrate specificities to N-degrons. Despite the known function of the N-end rule pathway in degradation of cytosolic proteins, the major phenotype of UBR2-deficient male mice is infertility caused by arrest of spermatocytes at meiotic prophase I. UBR2-deficient spermatocytes are impaired in transcriptional silencing of sex chromosome-linked genes and ubiquitylation of histone H2A. In this study we show that the recruitment of UBR2 to meiotic chromosomes spatiotemporally correlates to the induction of chromatin-associated ubiquitylation, which is significantly impaired in UBR2-deficient spermatocytes. UBR2 functions as a scaffold E3 that promotes HR6B/UbcH2-dependent ubiquitylation of H2A and H2B but not H3 and H4, through a mechanism distinct from typical polyubiquitylation. The E3 activity of UBR2 in histone ubiquitylation is allosterically activated by dipeptides bearing destabilizing N-terminal residues. Insufficient monoubiquitylation and polyubiquitylation on UBR2-deficient meiotic chromosomes correlate to defects in double strand break (DSB) repair and other meiotic processes, resulting in pachytene arrest at stage IV and apoptosis. Some of these functions of UBR2 are observed in somatic cells, in which UBR2 is a chromatin-binding protein involved in chromatin-associated ubiquitylation upon DNA damage. UBR2-deficient somatic cells show an array of chromosomal abnormalities, including hyperproliferation, chromosome instability, and hypersensitivity to DNA damage-inducing reagents. UBR2-deficient mice enriched in C57 background die upon birth with defects in lung expansion and neural development. Thus, UBR2, known as the recognition component of a major cellular proteolytic system, is associated with chromatin and controls chromatin dynamics and gene expression in both germ cells and somatic cells

Meeting the home-care needs of disabled older persons living in the community: does integrated services delivery make a difference?

<p>Abstract</p> <p>Background</p> <p>The PRISMA Model is an innovative coordination-type integrated-service-delivery (ISD) network designed to manage and better match resources to the complex and evolving needs of elders. The goal of this study was to examine the impact of this ISD network on unmet needs among disabled older persons living in the community.</p> <p>Methods</p> <p>Using data from the PRISMA study, we compared unmet needs of elders living in the community in areas with or without an ISD network. Disabilities and unmet needs were assessed with the Functional Autonomy Measurement System (SMAF). We used growth-curve analysis to examine changes in unmet needs over time and the variables associated with initial status and change. Sociodemographic characteristics, level of disability, self-perceived health status, cognitive functioning, level of empowerment, and the hours of care received were investigated as covariates. Lastly, we report the prevalence of needs and unmet needs for 29 activities in both areas at the end of the study.</p> <p>Results</p> <p>On average, participants were 83 years old; 62% were women. They had a moderate level of disability and mild cognitive problems. On average, they received 2.07 hours/day (SD = 1.08) of disability-related care, mostly provided by family. The findings from growth-curve analysis suggest that elders living in the area where ISD was implemented and those with higher levels of disability experience better fulfillment of their needs over time. Besides the area, being a woman, living alone, having a higher level of disability, more cognitive impairments, and a lower level of empowerment were linked to initial unmet needs (r²= 0.25; p < 0.001). At the end of the study, 35% (95% CI: 31% to 40%) of elders with needs living in the ISD area had at least one unmet need, compared to 67% (95% CI: 62% to 71%) in the other area. In general, unmet needs were highest for bathing, grooming, urinary incontinence, walking outside, seeing, hearing, preparing meals, and taking medications.</p> <p>Conclusions</p> <p>In spite of more than 30 years of home-care services in the province of Quebec, disabled older adults living in the community still have unmet needs. ISD networks such as the PRISMA Model, however, appear to offer an effective response to the long-term-care needs of the elderly.</p

Maternal TLR4 and NOD2 Gene Variants, Pro-Inflammatory Phenotype and Susceptibility to Early-Onset Preeclampsia and HELLP Syndrome

Background: Altered maternal inflammatory responses play a role in the development of preeclampsia and the hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome. We examined whether allelic variants of the innate immune receptors toli-like receptor 4 (TLR4) and nucleotide-binding oligomerization domain (NOD2), that impair the inflammatory response to endotexin are related to preeclampsia and HELLP syndrome. Methods and Finding: We determined five common mutations in TLR4 (D299G and T399I and NOD2 (R70W, G908R and L1007fs) in 340 primiparous women with a histo

Human and Non-Human Primate Genomes Share Hotspots of Positive Selection

Among primates, genome-wide analysis of recent positive selection is currently limited to the human species because it requires extensive sampling of genotypic data from many individuals. The extent to which genes positively selected in human also present adaptive changes in other primates therefore remains unknown. This question is important because a gene that has been positively selected independently in the human and in other primate lineages may be less likely to be involved in human specific phenotypic changes such as dietary habits or cognitive abilities. To answer this question, we analysed heterozygous Single Nucleotide Polymorphisms (SNPs) in the genomes of single human, chimpanzee, orangutan, and macaque individuals using a new method aiming to identify selective sweeps genome-wide. We found an unexpectedly high number of orthologous genes exhibiting signatures of a selective sweep simultaneously in several primate species, suggesting the presence of hotspots of positive selection. A similar significant excess is evident when comparing genes positively selected during recent human evolution with genes subjected to positive selection in their coding sequence in other primate lineages and identified using a different test. These findings are further supported by comparing several published human genome scans for positive selection with our findings in non-human primate genomes. We thus provide extensive evidence that the co-occurrence of positive selection in humans and in other primates at the same genetic loci can be measured with only four species, an indication that it may be a widespread phenomenon. The identification of positive selection in humans alongside other primates is a powerful tool to outline those genes that were selected uniquely during recent human evolution

Selective contacts drive charge extraction in quantum dot solids via asymmetry in carrier transfer kinetics

[EN] Colloidal quantum dot solar cells achieve spectrally selective optical absorption in a thin layer of solution-processed, size-effect tuned, nanoparticles. The best devices built to date have relied heavily on drift-based transport due to the action of an electric field in a depletion region that extends throughout the thickness of the quantum dot layer. Here we study for the first time the behaviour of the best-performing class of colloidal quantum dot films in the absence of an electric field, by screening using an electrolyte. We find that the action of selective contacts on photovoltage sign and amplitude can be retained, implying that the contacts operate by kinetic preferences of charge transfer for either electrons or holes. We develop a theoretical model to explain these experimental findings. The work is the first to present a switch in the photovoltage in colloidal quantum dot solar cells by purposefully formed selective contacts, opening the way to new strategies in the engineering of colloidal quantum dot solar cells.We thank the following agencies for support of this research: Ministerio de Educacion y Ciencia under project HOPE CSD2007-00007, Generalitat Valenciana (ISIC/2012/008) and Universitat Jaume I project 12I361.01/1. EHS and KWK acknowledge the Award KUS-11-009-21, made by King Abdullah University of Science and Technology (KAUST) and the International Cooperation of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (2012T100100740).Mora-Sero, I.; Bertoluzzi, L.; González-Pedro, V.; Gimenez, S.; Fabregat-Santiago, F.; Kemp, KW.; Sargent, EH.... (2013). Selective contacts drive charge extraction in quantum dot solids via asymmetry in carrier transfer kinetics. Nature Communications. 4:3272-3272. https://doi.org/10.1038/ncomms3272S327232724Grätzel, M., Janssen, R. A. J., Mitzi, D. B. & Sargent, E. H. Materials interface engineering for solution-processed photovoltaics. Nature 488, 304–312 (2012).Luther, J. M. et al. Schottky solar cells based on colloidal nanocrystal films. Nano Lett. 8, 3488–3492 (2008).Barkhouse, D. A. R. et al. Depleted bulk heterojunction colloidal quantum dot photovoltaics. Adv. Mater. 23, 3134–3138 (2011).Ip, A. H. et al. Hybrid passivated colloidal quantum dot solids. Nat. Nano 7, 577–582 (2012).Tang, J. et al. Colloidal-quantum-dot photovoltaics using atomic-ligand passivation. Nat. Mater. 10, 765–771 (2011).Lan, X. et al. Self-assembled, nanowire network electrodes for depleted bulk heterojunction solar cells. Adv. Mater. 25, 1769–1773 (2013).Liu, H. et al. Electron acceptor materials engineering in colloidal quantum dot solar cells. Adv. Mater. 23, 3832–3837 (2011).Jaegermann, W., Klein, A. & Mayer, T. Interface engineering of inorganic thin-film solar cells—materials-science challenges for advanced physical concepts. Adv. Mater. 21, 4196–4206 (2009).Sarasqueta, G., Choudhury, K. R., Subbiah, J. & So, F. Organic and inorganic blocking layers for solution-processed colloidal PbSe nanocrystal infrared photodetectors. Adv. Funct. Mater. 21, 167–171 (2010).Brown, P. R. et al. Improved current extraction from ZnO/PbS quantum dot heterojunction photovoltaics using a MoO3 interfacial layer. Nano Lett. 11, 2955–2961 (2011).Etgar, L. et al. Light energy conversion by mesoscopic PbS quantum dots/TiO2 heterojunction solar cells. ACS Nano 6, 3092–3099 (2012).Gao, J. et al. n-Type transition metal oxide as a hole extraction layer in PbS quantum dot solar cells. Nano Lett. 11, 3263–3266 (2011).Leschkies, K. S., Beatty, T. J., Kang, M. S., Norris, D. J. & Aydil, E. S. Solar cells based on junctions between colloidal PbSe nanocrystals and thin ZnO films. ACS Nano 3, 3638–3648 (2009).Gärtner, W. Depletion-layer photoeffects in semiconductors. Phys. Rev. 116, 84–87 (1959).Tang, J. et al. Schottky quantum dot solar cells stable in air under solar illumination. Adv. Mater. 22, 1398–1402 (2011).Willis, S. M., Cheng, C., Assender, H. E. & Watt, A. A. R. The transitional heterojunction behavior of PbS/ZnO colloidal quantum dot solar cells. Nano Lett. 12, 1522–1526 (2012).Zhitomirsky, D. et al. N-Type colloidal-quantum-dot solids for photovoltaics. Adv. Mater. 24, 6181–6185 (2012).Bisquert, J., Cahen, D., Rühle, S., Hodes, G. & Zaban, A. Physical chemical principles of photovoltaic conversion with nanoparticulate, mesoporous dye-sensitized solar cells. J. Phys. Chem. B 108, 8106–8118 (2004).Bisquert, J. & Garcia-Belmonte, G. On voltage, photovoltage, and photocurrent in bulk heterojunction organic solar cells. J. Phys. Chem. Lett. 2, 1950–1964 (2011).Ratcliff, E. L., Zacher, B. & Armstrong, N. R. Selective interlayers and contacts in organic photovoltaic cells. J. Phys. Chem. Lett. 2, 1337–1350 (2011).Walzer, K., Maennig, B., Pfeiffer, M. & Leo, K. Highly efficient organic devices based on electrically doped transport layers. Chem. Rev. 107, 1233–1271 (2007).Hodes, G., Howell, I. D. J. & Peter, L. M. Nanocristallyne photoelectrochemical cells. A new concept in photovoltaic cells. J. Electrochem. Soc. 139, 3136–3140 (1992).Bisquert, J., Garcia-Belmonte, G. & Fabregat Santiago, F. Modeling the electric potential distribution in the dark in nanoporous semiconductor electrodes. J. Solid State Electr 3, 337–347 (1999).Yu, D., Wang, C. & Guyot-Sionnest, P. n-type conducting CdSe nanocrystal solids. Science 300, 1277–1280 (2003).Guyot-Sionnest, P. Charging colloidal quantum dots by electrochemistry. Microchim. Acta 160, 309–314 (2008).Vanmaekelbergh, D. Self-assembly of colloidal nanocrystals as route to novel classes of nanostructured materials. Nano Today 6, 419–437 (2011).Vanmaekelbergh, D. & Liljerorth, P. Electron-conducting quantum dot solids: novel materials based on colloidal semiconductor nanocrystals. Chem. Soc. Rev. 34, 299–312 (2005).Roest, A. L., Kelly, J. J. & Vanmaekelbergh, D. Coulomb blockade of electron transport in a ZnO quantum-dot solid. Appl. Phys. Lett. 83, 5530–5532 (2003).Roest, A. L., Kelly, J. J., Vanmaekelbergh, D. & Meulenkamp, E. A. Staircase in the electron mobility of a ZnO quantum dot assembly due to shell filling. Phys. Rev. Lett. 89, 036801 (2002).Pattantyus-Abraham, A. G. et al. Depleted-heterojunction colloidal quantum dot solar cells. ACS Nano 4, 3374–3380 (2010).Hyun, B.-R. et al. Electron injection from colloidal PbS quantum dots into titanium dioxide nanoparticles. ACS Nano 2, 2206–2212 (2008).Ning, Z. et al. All-inorganic colloidal quantum dot photovoltaics employing solution-phase halide passivation. Adv. Mater. 24, 6295–6299 (2012).Gross, D. et al. Charge separation in type II tunneling multilayered structures of CdTe and CdSe nanocrystals directly proven by surface photovoltage spectroscopy. J. Am. Chem. Soc. 132, 5981–5983 (2010).Abkowitz, M., Facci, J. S. & Rehm, J. Direct evaluation of contact injection efficiency into small molecule based transport layers: Influence of extrinsic factors. J. Appl. Phys. 83, 2670–2676 (1998).Meyer, J. & Kahn, A. Electronic structure of molybdenum-oxide films and associated charge injection mechanisms in organic devices. J. Photon. Energy 1, 011109 (2011).Lee, M. M., Teuscher, J., Miyasaka, T., Murakami, T. N. & Snaith, H. J. Efficient hybrid solar cells based on meso-superstructured organometal halide perovskites. Science 338, 643–647 (2012).Scholes, G. D., Jones, M. & Kumar, S. Energetics of photoinduced electron-transfer reactions decided by quantum confinement. J. Phys. Chem. C 111, 13777–13785 (2007).Bässler, H., Arkhipov, V. I., Emelianova, E. V. & Tak, Y. H. Charge injection into light-emitting diodes: theory and experiment. J. Appl. Phys. 84, 848–856 (1998).Baldo, M. A. & Forrest, S. R. Interface-limited injection in amorphous organic semiconductors. Phys. Rev. B 64, 085201 (2001).Scott, J. C. & Malliaras, G. G. Charge injection and recombination at the metal-organic interface. Chem. Phys. Lett. 299, 115 (1999).Shen, Y., Hosseini, A. R., Wong, M. H. & Malliaras, G. G. How to make ohmic contacts to organic semiconductors. Chem. Phys. Chem. 5, 16–25 (2004).Hung, L. S., Tang, C. W. & Mason, M. G. Enhanced electron injection in organic electroluminescence devices using an Al/LiF electrode. Appl. Phys. Lett. 70, 152–154 (1997).Ding, H. & Gao, Y. Au/LiF/tris(8-hydroxyquinoline) aluminum interfaces. Appl. Phys. Lett. 91, 172107 (2007).Rodriguez, J. A., Jirsak, T., Chaturvedi, S. & Dvorak, J. Chemistry of SO2 and NO2 on ZnO(0001)-Zn and ZnO powders: changes in reactivity with surface structure and composition. J. Mol. Catal. A Chem. 167, 47–57 (2001)