Optimizing Models of the North Atlantic Spring Bloom Using Physical, Chemical and Bio-Optical Observations from a Lagrangian Float

The North Atlantic spring bloom is one of the main events that lead to carbon export to the deep ocean and drive oceanic uptake of CO(2) from the atmosphere. Here we use a suite of physical, bio-optical and chemical measurements made during the 2008 spring bloom to optimize and compare three different models of biological carbon export. The observations are from a Lagrangian float that operated south of Iceland from early April to late June, and were calibrated with ship-based measurements. The simplest model is representative of typical NPZD models used for the North Atlantic, while the most complex model explicitly includes diatoms and the formation of fast sinking diatom aggregates and cysts under silicate limitation. We carried out a variational optimization and error analysis for the biological parameters of all three models, and compared their ability to replicate the observations. The observations were sufficient to constrain most phytoplankton-related model parameters to accuracies of better than 15 %. However, the lack of zooplankton observations leads to large uncertainties in model parameters for grazing. The simulated vertical carbon flux at 100 m depth is similar between models and agrees well with available observations, but at 600 m the simulated flux is larger by a factor of 2.5 to 4.5 for the model with diatom aggregation. While none of the models can be formally rejected based on their misfit with the available observations, the model that includes export by diatom aggregation has a statistically significant better fit to the observations and more accurately represents the mechanisms and timing of carbon export based on observations not included in the optimization. Thus models that accurately simulate the upper 100 m do not necessarily accurately simulate export to deeper depths

A Water Recovery System Evolved for Exploration

A new water recovery system designed towards fulfillment of NASA's Vision for Space Exploration is presented. This water recovery system is an evolution of the current state-of-the-art system. Through novel integration of proven technologies for air and water purification, this system promises to elevate existing technology to higher levels of optimization. The novel aspect of the system is twofold: Volatile organic contaminants will be removed from the cabin air via catalytic oxidation in the vapor phase, prior to their absorption into the aqueous phase, and vapor compression distillation technology will be used to process the condensate and hygiene waste streams in addition to the urine waste stream. Oxidation kinetics dictate that removal of volatile organic contaminants from the vapor phase is more efficient. Treatment of the various waste streams by VCD will reduce the load on the expendable ion exchange and adsorption media which follow, and on the aqueous-phase volatile removal assembly further downstream. Incorporating these advantages will reduce the weight, volume, and power requirements of the system, as well as resupply

Perthes' disease of the hip: socioeconomic inequalities and the urban environment.

INTRODUCTION: Perthes' disease is a puzzling childhood hip disorder for which the aetiology is unknown. It is known to be associated with socioeconomic deprivation. Urban environments have also been implicated as a risk factor, however socioeconomic deprivation often occurs within urban environments and it is unclear if this association is the result of confounding. The objective of the current work was to gain a greater understanding of the influence of the urban/rural environment in Perthes' disease. METHODS: This was a descriptive observational study using the Scottish Morbidity Record, based in Scotland, UK using data from 2000-2010. A total of 443 patients with a discharge diagnosis of Perthes' disease were included. Socioeconomic deprivation was determined using the Scottish Index of Multiple Deprivation, and exposure to the 'urban environment' was recorded based on the Scottish Urban-Rural Classification. RESULTS: There was a strong association with socioeconomic deprivation, with rates among the most deprived quintile more than twice those of the most affluent (RR 2.1 (95% CI 1.5 to 2.9)). Urban areas had a greater rate of Perthes' disease discharges (RR 1.8 (95% CI 1.1 to 3.2)), though this was a reflection of greater deprivation in urban areas. Stratification for socioeconomic deprivation revealed similar discharge rates in urban and rural environments, suggesting that the aetiological determinants were not independently associated with urban environments. CONCLUSIONS: The occurrence of Perthes' disease within urban environments is high, yet this appears to be a reflection of higher socioeconomic deprivation exposure. Disease rates appear equivalent in similarly deprived urban and non-urban areas, suggesting that the determinant is not a consequence of the urban environment

A Human Oral Fluid Assay for D- and L- Isomer Detection of Amphetamine and Methamphetamine Using Liquid-Liquid Extraction

Medical providers are increasingly confronted with clinical decision-making that involves (meth)amphetamines. And clinical laboratories need a sensitive, efficient assay for routine assessment of D- and L-isomers to determine the probable source of these potentially illicit analytes. This paper presents a validated method of D- and L-isomer detection in human oral fluid from an extract used for determination of a large oral fluid assay (63 analytes) on an older AB SCIEX 4000 instrument. Taken from the positive extract, D- and L-analytes were added. The method for extraction included addition of internal standard and a 2-step liquid-liquid extraction and dry-down step to concentrate and clean the samples. The samples were suspended in 50% MeOH in water, diluted with mobile phase, with separation and detection accomplished using LC-MS/MS to determine analyte concentration. Once samples were confirmed positive for (meth)amphetamine from the large oral fluid assay, they were further examined for the enantiomeric forms with 50 μl aliquots of the standards and samples of interest combined with 450 μl of D- and L-assay mobile phase, then analyzed using chiral column separation, and LC-MS/MS detection with standard curve spanning the range from 2.5 to 1000 ng/mL. The result is a sensitive and accurate detection of D- and L-isomers of amphetamine and methamphetamine in human oral fluid performed on an older model mass spectrometer (AB SCIEX 4000). The novelty of this assay is twofold (a) the 2-step liquid-liquid extraction and dry-down step to concentrate and clean the samples, and (b) its adoption characteristics as a reflex test from a large ODT panel without the need to invest in newer or expensive LC-MS/MS instruments. Finally, this assay also has potential to add a valuable option to high-throughput laboratories seeking a D- and L-testing alternative to urine drug testing methods

Analysis of D- and L- Isomers of (Meth)amphetamine in Human K2EDTA Plasma

Methamphetamine and its metabolite amphetamine are frequently abused drugs. Whether obtained legally or from clandestine laboratories it is of relevance to determine the chiral makeup of these drugs for investigative purpose. Although urine and oral fluid matrices are commonly offered, less available to independent laboratories are techniques to verify dextro (D-) or levo (L-) (meth)amphetamine from human K2EDTA plasma. This paper outlines the development and validation of a method that includes the addition of internal standard and a two-step liquid-liquid extraction to remove the analytes from human K2EDTA plasma by triple quadrupole mass spectrometry (LC-MS/MS). The assay was validated according to the United States Food and Drug Administration and College of American Pathologists guidelines, including assessment of the following parameters in plasma validation samples: linear range, limit of detection, lower limit of quantitation, matrix effects, inter- and intra-day assay precision and accuracy, carry over, linearity of dilution, matrix effects and stability. The outcome is a validated and reliable method for the determination of D- and L- isomer concentration of meth(amphetamine) human plasma samples that can be easily adopted by independent clinical laboratories

Quantifying 64 drugs, illicit substances, and D- and L- isomers in human oral fluid with liquid-liquid extraction

Although human oral fluid has become more routine for quantitative drug detection in pain management, detecting a large scope of medications and substances is costly and technically challenging for laboratories. This paper presents a quantitative assay for 64 pain medications, illicit substances, and drug metabolites in human oral fluid. The novelty of this assay is that it was developed on an older model AB SCIEX 4000 instrument and renders obscure the need for more technical and expensive laboratory equipment. This method includes addition of internal standard and a 2-step liquid-liquid extraction and dry-down step to concentrate and clean the samples. The samples were suspended in 50% MeOH in water and separation and detection was accomplished using triple quadrupole mass spectrometry (LC-MS/MS). Separation was achieved using reverse-phase liquid chromatography with detection by LC-MS/MS. A second injection was done in negative mode to determine THC-COOH concentration as an indicator of THC. An aliquot of the (already) extracted samples was analyzed for D- and L- isomers of amphetamine and methamphetamine using a chiral column. The standard curve spanned from 5 to 2000 ng/mL for most of the analytes (1 to 2000 ng/mL for fentanyl and THC-COOH) and up to 1000 ng/mL for 13 analytes. Pregabalin and gabapentin ranged from 25 to 2000 ng/mL. The result is a low-cost method for the sensitive detection of a wide-ranging oral fluid menu for pain management. This assay has a high sensitivity, and good precision and accuracy for all analytes with an older model mass spectrometer

Applying phylogenomics to understand the emergence of Shiga Toxin producing Escherichia coli O157:H7 strains causing severe human disease in the United Kingdom

Shiga Toxin producing Escherichia coli (STEC) O157:H7 is a recently emerged zoonotic pathogen with considerable morbidity. Since the serotype emerged in the 1980s, research has focussed on unravelling the evolutionary events from the E. coli O55:H7 ancestor to the contemporaneous globally dispersed strains. In this study the genomes of over 1000 isolates from human clinical cases and cattle, spanning the history of STEC O157:H7 in the United Kingdom were sequenced. Phylogenetic analysis reveals the ancestry, key acquisition events and global context of the strains. Dated phylogenies estimate the time to the most recent common ancestor of the current circulating global clone to 175 years ago, followed by rapid diversification. We show the acquisition of specific virulence determinates occurred relatively recently and coincides with its recent detection in the human population. Using clinical outcome data from 493 cases of STEC O157:H7 we assess the relative risk of severe disease including HUS from each of the defined clades in the population and show the dramatic effect Shiga toxin complement has on virulence. We describe two strain replacement events that have occurred in the cattle population in the UK over the last 30 years; one resulting in a highly virulent strain that has accounted for the majority of clinical cases in the UK over the last decade. This work highlights the need to understand the selection pressures maintaining Shiga-toxin encoding bacteriophages in the ruminant reservoir and the study affirms the requirement for close surveillance of this pathogen in both ruminant and human populations

PRINT: A Novel Platform Toward Shape and Size Specific Nanoparticle Theranostics

Nanotheranostics represents the next generation of medicine, fusing nanotechnology, therapeutics, and diagnostics. By integrating therapeutic and imaging agents into one nanoparticle, this new treatment strategy has the potential not only to detect and diagnose disease but also to treat and monitor the therapeutic response. This capability could have a profound impact in both the research setting as well as in a clinical setting. In the research setting, such a capability will allow research scientists to rapidly assess the performance of new therapeutics in an effort to iterate their designs for increased therapeutic index and efficacy. In the clinical setting, theranostics offers the ability to determine whether patients enrolling in clinical trials are responding, or are expected to respond, to a given therapy based on the hypothesis associated with the biological mechanisms being tested. If not, patients can be more quickly removed from the clinical trial and shifted to other therapeutic options. To be effective, these theranostic agents must be highly site specific. Optimally, they will carry relevant cargo, demonstrate controlled release of that cargo, and include imaging probes with a high signal-to-noise ratio

PhyloMarker—A Tool for Mining Phylogenetic Markers Through Genome Comparison: Application of the Mouse Lemur (Genus Microcebus) Phylogeny

Molecular phylogeny is a fundamental tool to understanding the evolution of all life forms. One common issue faced by molecular phylogeny is the lack of sufficient molecular markers. Here, we present PhyloMarker, a phylogenomic tool designed to find nuclear gene markers for the inference of phylogeny through multiple genome comparison. Around 800 candidate markers were identified by PhyloMarker through comparison of partial genomes of Microcebus and Otolemur. In experimental tests of 20 randomly selected markers, nine markers were successfully amplified by PCR and directly sequenced in all 17 nominal Microcebus species. Phylogenetic analyses of the sequence data obtained for 17 taxa and nine markers confirmed the distinct lineage inferred from previous mtDNA data. PhyloMarker has also been used by other projects including the herons (Ardeidae, Aves) phylogeny and the Wood mice (Muridae, Mammalia) phylogeny. All source code and sample data are made available at http://bioinfo-srv1.awh.unomaha.edu/phylomarker/

Periodontal Regeneration â Furcation Defects: A Consensus Report From the AAP Regeneration Workshop

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141183/1/jpers131.pd