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Bhargavi Ramanathan, Andrew M Boddicker, Timberley M Roane, Annika C Mosier
Extremely acidic and metal-rich acid mine drainage (AMD) waters can have severe toxicological effects on aquatic ecosystems. AMD has been shown to completely halt nitrification, which plays an important role in transferring nitrogen to higher organisms and in mitigating nitrogen pollution. We evaluated the gene abundance and diversity of nitrifying microbes in AMD-impacted sediments: ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and nitrite-oxidizing bacteria (NOB). Samples were collected from the Iron Springs Mining District (Ophir, CO, United States) during early and late summer in 2013 and 2014...
2017: Frontiers in Microbiology
Wenjie Yang, Yong Wang, Kanako Tago, Shinichi Tokuda, Masahito Hayatsu
Dicyandiamide, a routinely used commercial nitrification inhibitor (NI), inhibits ammonia oxidation catalyzed by ammonia monooxygenase (AMO). Phenylhydrazine hydrochloride has shown considerable potential for the development of next-generation NIs targeting hydroxylamine dehydrogenase (HAO). The effects of the AMO inhibitor and the HAO inhibitor on ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) present in agricultural soils have not been compared thus far. In the present study, the effects of the two inhibitors on soil nitrification and the abundance of AOA and AOB as well as their community structure were investigated in a soil microcosm using quantitative polymerase chain reaction and pyrosequencing...
2017: Frontiers in Microbiology
Michael R Peabody, Thomas R O'Neill, Aimee R Eden, James C Puffer
BACKGROUND: Due to the Accreditation Council for Graduate Medical Education (ACGME)/American Osteopathic Association (AOA) single-accreditation model, the specialty of family medicine may see as many as 150 programs and 500 trainees in AOA-accredited programs seek ACGME accreditation. This analysis serves to better understand the composition of physicians completing family medicine residency training and their subsequent certification by the American Board of Family Medicine. METHODS: We identified residents who completed an ACGME-accredited or dual-accredited family medicine residency program between 2006 and 2016 and cross-tabulated the data by graduation year and by educational background (US Medical Graduate-MD [USMG-MD], USMG-DO, or International Medical Graduate-MD [IMG-MD]) to examine the cohort composition trend over time...
November 2017: Journal of the American Board of Family Medicine: JABFM
Sarah A Almahboub, Tanja Narancic, Marc Devocelle, Shane T Kenny, William Palmer-Brown, Cormac Murphy, Jasmina Nikodinovic-Runic, Kevin E O'Connor
Terminal modification of peptides is frequently used to improve their hydrophobicity. While N-terminal modification with fatty acids (lipidation) has been reported previously, C-terminal lipidation is limited as it requires the use of linkers. Here we report the use of a biocatalyst for the production of an unnatural fatty amino acid, (S)-2-aminooctanoic acid (2-AOA) with enantiomeric excess > 98% ee and the subsequent use of 2-AOA to modify and improve the activity of an antimicrobial peptide. A transaminase originating from Chromobacterium violaceum was employed with a conversion efficiency 52-80% depending on the ratio of amino group donor to acceptor...
November 25, 2017: Applied Microbiology and Biotechnology
Scott L Zuckerman, Patrick D Kelly, Michael C Dewan, Peter J Morone, Aaron M Yengo-Kahn, Jordan A Magarik, Ronnie E Baticulon, Edie E Zusman, Gary S Solomon, John C Wellons
BACKGROUND: Neurosurgical educators strive to identify the best applicants, yet formal study of resident selection has proven difficult. We conducted a systematic review to answer the following question: what objective and subjective pre-residency factors predict resident success? METHODS: PubMed, ProQuest, Embase, and the CINAHL databases were queried from 1952-2015 for literature reporting the impact of pre-residency factors (PRF) on outcomes of residency success (RS), among neurosurgery and all surgical sub-specialties...
November 23, 2017: World Neurosurgery
Slavisa Tomic, Marko Beko, Rui Dinis, João Pedro Gomes
This work addresses the problem of tracking a signal-emitting mobile target in wireless sensor networks (WSNs) with navigated mobile sensors. The sensors are properly equipped to acquire received signal strength (RSS) and angle of arrival (AoA) measurements from the received signal, while the target transmit power is assumed not known. We start by showing how to linearize the highly non-linear measurement model. Then, by employing a Bayesian approach, we combine the linearized observation model with prior knowledge extracted from the state transition model...
November 21, 2017: Sensors
Rafaela Cáceres, Krystyna Malińska, Oriol Marfà
Composting could be regarded as a process of processes because it entails a number of complex chemical and microbiological reactions and transformations. Nitrification is one of such processes that normally takes place during the curing phase. This process has been studied in detail for wastewater treatment, and it is becoming an extensively studied topic within composting. In the past, nitrate presence in compost has been clearly perceived as a maturation indicator; however, nowadays, nitrate formation is also conceived as a way of conserving nitrogen in compost...
November 15, 2017: Waste Management
Takafumi Kataoka, Koji Suzuki, Tomohisa Irino, Masanobu Yamamoto, Seigo Higashi, Hongbin Liu
Microbial nitrification is a key process in the nitrogen cycle in the continental shelf ecosystems. The genotype compositions and abundance of the ammonia monooxygenase gene, amoA, derived from ammonia-oxidizing archaea (AOA) and bacteria (AOB) in two size fractions (2-10 and 0.2-2 µm), were investigated in the East China Sea (ECS) in May 2008 using PCR-denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR). Four sites were selected across the continental shelf edge: continental shelf water (CSW), Kuroshio branch water (KBW), transition between CSW and KBW (TCSKB) and coastal KBW (CKBW)...
November 16, 2017: Archives of Microbiology
Mohammed A G Al-Sadoon, Nazar T Ali, Yousf Dama, Abdulkareim Zuid, Stephen M R Jones, Raed A Abd-Alhameed, James M Noras
This paper proposes a new low complexity angle of arrival (AOA) method for signal direction estimation in multi-element smart wireless communication systems. The new method estimates the AOAs of the received signals directly from the received signals with significantly reduced complexity since it does not need to construct the correlation matrix, invert the matrix or apply eigen-decomposition, which are computationally expensive. A mathematical model of the proposed method is illustrated and then verified using extensive computer simulations...
November 15, 2017: Sensors
Scott E Porter, Afshin E Razi, T Bennett Ramsey
Residency selection is a perennial multifactorial process that differs considerably from the recruitment processes that other professional occupations enjoy. The 2016 meeting of the American Orthopaedic Association's Council of Orthopaedic Residency Directors highlighted a series of symposia that sought to present a novel manner of resident selection. Specifically, the presenters for each symposium were asked to do the following: present some general recruitment best practices in industries outside of medicine, present how branding of a program may translate into a better interview season, investigate evidence that the applicant pool to orthopaedic surgery may have changed and that residency program brands may have to reflect this, and assess our current evaluation techniques for talent identification and resident selection with respect to a specific department's appearance or brand...
November 15, 2017: Journal of Bone and Joint Surgery. American Volume
Minerva Ferrer-Buitrago, Davina Bonte, Petra De Sutter, Luc Leybaert, Bjorn Heindryckx
Oocyte activation is a calcium (Ca(2+)) dependent process that has been investigated in depth, in particular regarding its impact in assisted reproduction technology (ART). Following a standard model of signal transduction, Ca(2+) drives the meiotic progression upon fertilization in all species studied to date. However, Ca(2+) changes during oocyte activation are species specific and they can be classified in two modalities based on the pattern defined by the Ca(2+) signature: a single Ca(2+) transient (e.g...
November 9, 2017: Reproduction: the Official Journal of the Society for the Study of Fertility
Dandan Zhou, Qi Chen
The present study comprises two parts, an object picture naming task and rating tasks, and reports naming latencies and norms for 435 color images in Mandarin Chinese. These norms include name agreement (%), H-value, concept agreement, familiarity, visual complexity, age of acquisition (AOA) based on adult ratings, object agreement, viewpoint agreement, word frequency, and word length. We examined correlations between the norms and explored the internal structure among these correlative variables by a factor analysis...
2017: Frontiers in Psychology
Qing-Fang Bi, Qiu-Hui Chen, Xiao-Ru Yang, Hu Li, Bang-Xiao Zheng, Wei-Wei Zhou, Xiao-Xia Liu, Pei-Bin Dai, Ke-Jie Li, Xian-Yong Lin
Soil amended with single biochar or nitrogen (N) fertilizer has frequently been reported to alter soil nitrification process due to its impact on soil properties. However, little is known about the dynamic response of nitrification and ammonia-oxidizers to the combined application of biochar and N fertilizer in intensive vegetable soil. In this study, an incubation experiment was designed to evaluate the effects of biochar and N fertilizer application on soil nitrification, abundance and community shifts of ammonia-oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) in Hangzhou greenhouse vegetable soil...
November 7, 2017: AMB Express
Linqiong Wang, Yi Li, Lihua Niu, Wenlong Zhang, Huanjun Zhang, Longfei Wang, Peifang Wang
Ammonia oxidation plays a fundamental role in river nitrogen cycling ecosystems, which is normally governed by both ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB). Co-contamination of typical emerging pollutant Polybrominated diphenyl ethers (PBDEs) and heavy metal on AOA and AOB communities in river sediments remains unknown. In this study, multiple analytical tools, including high-throughput pyrosequencing and real-time quantitative PCR (qPCR), were used to reveal the ammonia monooxygenase (AMO) activity, subunit alpha (amoA) gene abundance, and community structures of AOA and AOB in river sediments...
October 12, 2017: Chemosphere
Ángel Barón-Sola, Francisca Fernández Del Campo, Soledad Sanz-Alférez
Arginine (Arg) and glycine (Gly) seem to be the only substrates accepted by the amidinotransferase that catalyze the first step of the synthesis pathway of the cyanotoxin cylindrospermopsin (CYN), leading to guanidinoacetate (GAA). Here, the effect of these amino acids on the production of CYN in cultures of the cylindrospermopsin-producing strain, Aphanizomenon ovalisporum UAM-MAO, has been studied. Arg clearly increased CYN content, the increment appearing triphasic along the culture. On the contrary, Gly caused a decrease of CYN, observable from the first day on...
November 1, 2017: Toxins
Juan Chen, Pei-Fang Wang, Chao Wang, Xun Wang, Han Gao
While nitrogen (N) fixation and ammonia oxidation by microorganisms are two important N cycling processes, little is known about how the microbes that drive these two processes respond when sediments are contaminated with persistent organic pollutants. In this study, we carried out a laboratory microcosm experiment to examine the effects of decabromodiphenyl ether (BDE-209), either on its own or combined with a common mangrove species, Avicennia marina, on the abundance, diversity, and community composition of N-fixing bacteria (NFB) and ammonia-oxidizing archaea (AOA) and bacteria (AOB) in mangrove sediments...
October 31, 2017: Science of the Total Environment
Stijn Wielandt, Lieven De Strycker
Indoor radio frequency positioning systems enable a broad range of location aware applications. However, the localization accuracy is often impaired by Non-Line-Of-Sight (NLOS) connections and indoor multipath effects. An interesting evolution in widely deployed communication systems is the transition to multi-antenna devices with beamforming capabilities. These properties form an opportunity for localization methods based on Angle of Arrival (AoA) estimation. This work investigates how multipath propagation can be exploited to enhance the accuracy of AoA localization systems...
November 2, 2017: Sensors
D C Swanson, R L Culver
Small aperture arrays (size less than a wavelength) can be used for passive angle of arrival (AOA) estimation of both broadband and narrowband signals in the frequency domain. Phase differences across the array are measured in the frequency domain and can be spectrally averaged if desired for stationary source AOA and frequencies. The array is capable of measuring multiple target AOAs so long as each target produces unique frequencies or radiates in unique frequency bandwidths. Broadband and narrowband signals from targets can be collected from the fast Fourier transform (FFT) bins and summed by arrival angle in elevation and azimuth using a bearing histogram where the amplitude is displayed in dB...
October 2017: Journal of the Acoustical Society of America
Xavier Vila-Farrés, Raquel Parra-Millán, Viviana Sánchez-Encinales, Monica Varese, Rafael Ayerbe-Algaba, Nuria Bayó, Salvador Guardiola, María Eugenia Pachón-Ibáñez, Martin Kotev, Jesús García, Meritxell Teixidó, Jordi Vila, Jerónimo Pachón, Ernest Giralt, Younes Smani
Preventing the adhesion of pathogens to host cells provides an innovative approach to tackling multidrug-resistant bacteria. In this regard, the identification of outer membrane protein A (OmpA) as a key bacterial virulence factor has been a major breakthrough. The use of virtual screening helped us to identify a cyclic hexapeptide AOA-2 that inhibits the adhesion of Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli to host cells and the formation of biofilm, thereby preventing the development of infection in vitro and in a murine sepsis peritoneal model...
October 31, 2017: Scientific Reports
Magalí S Marcos, Anthony D Barboza, Rosalinde M Keijzer, Hendrikus J Laanbroek
Mangrove species are adapted to grow at specific zones in a tidal gradient. Here we tested the hypothesis that the archaeal and bacterial ammonia-oxidizing microbial communities differ in soils dominated by the mangrove species Avicennia germinans and Rhizophora mangle. Two of the sampling locations were tidal locations, while the other location was impounded. Differences in the community compositions of ammonia-oxidizing archaea (AOA) and bacteria (AOB) were analyzed by denaturing gradient gel electrophoresis (DGGE) of amoA genes and by MiSeq 16S rRNA gene-sequencing...
October 23, 2017: Microbial Ecology
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