NMR surface relaxivity in a time-dependent porous system

We demonstrate an unexpected decay-recovery behaviour in the time-dependent $^{1}\mathrm{H}$ NMR relaxation times of water confined within a hydrating porous material. Our observations are rationalised by considering the combined effects of decreasing material pore size and evolving interfacial chemistry, which facilitate a transition between surface-limited and diffusion-limited relaxation regimes. Such behaviour necessitates the realisation of temporally evolving surface relaxivity, highlighting potential caveats in the classical interpretation of NMR relaxation data obtained from complex porous systems.Comment: 12 pages, 2 figure

Biochemical Systematics of Notothenioid Fishes from Antarctica

Genetic variation at 30 protein-coding loci was examined in seven forms of notothenioid fishes from Antarctica. Multilocus heterozygosity varied from 0.018 to 0.078 across taxa. An analysis of the allozyme data revealed the probable existence of an unrecognized cryptic species within Trematomu5 bemacchii. Pagothenia borchgrevinki is as closely related to some species of Trematomus as are some species of Trematomus to each other. Speciation among the species of Trematomus and Pagothenia appears to have taken place primarily after the separation of Antarctica from Australia

Impact of microplastics on organic fouling of hollow fiber membranes

Given the potential hazards of microplastics (MPs), it is desirable to efficiently remove them during wastewater treatment processes. To this end, ultrafiltration (UF) membranes can significantly increase the removal of MPs, however the fouling of such membrane modules can also be impacted by the presence of MPs. Magnetic Resonance Imaging (MRI) was used here to non-invasively quantify the effect of polyethylene (PE) MPs accumulation in a 3D UF hollow fiber (HF) membrane module containing 400 fibers, via direct non-invasive velocity imaging of the flow distribution between individual fibers during module operation. The co-effect of MPs and alginate (a common organic model foulant mimicking extracellular polymeric substances (EPS)) on fouling of the HF module was then explored. Flow was initially equally distributed with fouling causing flow in particular fibers to be significantly reduced. Fouling with MPs resulted in minimal flow distribution disruption and was easily remediated hydraulically, in contrast alginate fouling required chemical cleaning in order to fully restore homogeneous flow distribution between the fibers. The presence of both MPs and alginate resulted in a more heterogeneous disruption of the fibre flow distribution due to fouling and resulted in much more effective hydraulic cleaning of the module

High serum immunoglobulin g and m levels predict freedom from adverse cardiovascular events in hypertension: a nested case-control substudy of the Anglo-Scandinavian cardiac outcomes trial

Aims: We aimed to determine whether the levels of total serum IgM and IgG, together with specific antibodies against malondialdehyde-conjugated low-density lipoprotein (MDA-LDL), can improve cardiovascular risk discrimination. Methods and Results: The Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) randomized 9098 patients in the UK and Ireland into the Blood Pressure-Lowering Arm. 485 patients that had cardiovascular (CV) events over 5.5 years were age and sex matched with 1367 controls. Higher baseline total serum IgG, and to a lesser extent IgM, were associated with decreased risk of CV events (IgG odds ratio (OR) per one standard deviation (SD) 0.80 [95% confidence interval, CI 0.72,0.89], p < 0.0001; IgM 0.83[0.75,0.93], p = 0.001), and particularly events due to coronary heart disease (CHD) (IgG OR 0.66 (0.57,0.76); p < 0.0001, IgM OR 0.81 (0.71,0.93); p = 0.002). The association persisted after adjustment for a basic model with variables in the Framingham Risk Score (FRS) as well as following inclusion of C-reactive protein (CRP) and N-terminal pro-B-type natriuretic peptide (NtProBNP). IgG and IgM antibodies against MDA-LDL were also associated with CV events but their significance was lost following adjustment for total serum IgG and IgM respectively. The area under the receiver operator curve for CV events was improved from the basic risk model when adding in total serum IgG, and there was improvement in continuous and categorical net reclassification (17.6% and 7.5% respectively) as well as in the integrated discrimination index. Conclusion: High total serum IgG levels are an independent predictor of freedom from adverse cardiovascular events, particularly those attributed to CHD, in patients with hypertension

Harnessing the power of metal-organic frameworks to develop microplastic fouling resistant forward osmosis membranes

With the gradual increase of microplastics (MPs) in water and wastewater streams, it is imperative to investigate their removal using tertiary treatment systems to minimize and preferably prevent their entrance into aquatic environments. Forward osmosis (FO) is a non-pressurized membrane process with potential applications in MPs removal from wastewater. However, efficient application of FO systems relies on developing high-performance FO membranes with low fouling tendency. MPs are proven as emerging foulants in membrane systems, diminishing their performance and lifetime and this highlights the need to consider MP fouling in developing sustainable membranes. The current study focuses on a novel modification of thin film composite (TFC) FO membranes by MIL-53(Fe) as a water-stable and hydrophilic metal-organic framework. Experimental results demonstrated that the optimized FO membrane (0.2 wt% MIL-53(Fe)) achieved a significantly higher water flux (90% increase) with a 23% less reverse salt flux. The modified membrane also had significantly less flux decline in fouling experiments and higher flux recovery after physical cleaning compared to the control membrane affirming its higher antifouling efficiency. MIL-53(Fe) integration in the FO substrate proved to be a practical method for developing high-performance TFC FO membranes with improved antifouling properties against MPs and organic foulants

Imaging of membrane concentration polarization by NaCl using 23Na nuclear magnetic resonance

Forward osmosis (FO) and reverse osmosis (RO) membrane processes differ in their driving forces: osmotic pressure versus hydraulic pressure. Concentration polarization (CP) can adversely affect both performance and lifetime in such membrane systems. In order to mitigate against CP, the extent and severity of it need to be predicted more accurately through advanced online monitoring methodologies. Whilst a variety of monitoring techniques have been used to study the CP mechanism, there is still a pressing need to develop and apply non-invasive, in situ techniques able to produce quantitative, spatially resolved measurements of heterogeneous solute concentration in, and adjacent to, the membrane assembly as caused by the CP mechanism. To this end, 23Na magnetic resonance imaging (MRI) is used to image the sodium ion concentration within, and near to, both FO and RO composite membranes for the first time; this is also coupled with 1H MRI mapping of the corresponding water distribution. As such, it is possible to directly image salt accumulation due to CP processes during desalination. This was consistent with literature expectations and serves to confirm the suitability of 23Na MRI as a novel non-invasive technique for CP studies

XO-5b: A Transiting Jupiter-sized Planet With A Four Day Period

The star XO-5 (GSC 02959-00729, V=12.1, G8V) hosts a Jupiter-sized, Rp=1.15+/-0.12 Rjup, transiting extrasolar planet, XO-5b, with an orbital period of P=4.187732+/-0.00002 days. The planet mass (Mp=1.15+/-0.08 Mjup) and surface gravity (gp=22+/-5 m/s^2) are significantly larger than expected by empirical Mp-P and Mp-P-[Fe/H] relationships. However, the deviation from the Mp-P relationship for XO-5b is not large enough to suggest a distinct type of planet as is suggested for GJ 436b, HAT-P-2b, and XO-3b. By coincidence XO-5 overlies the extreme H I plume that emanates from the interacting galaxy pair NGC 2444/NGC 2445 (Arp 143).Comment: 10 pages, 9 Figures, Submitted to Ap

Ground-layer wavefront reconstruction from multiple natural guide stars

Observational tests of ground layer wavefront recovery have been made in open loop using a constellation of four natural guide stars at the 1.55 m Kuiper telescope in Arizona. Such tests explore the effectiveness of wide-field seeing improvement by correction of low-lying atmospheric turbulence with ground-layer adaptive optics (GLAO). The wavefronts from the four stars were measured simultaneously on a Shack-Hartmann wavefront sensor (WFS). The WFS placed a 5 x 5 array of square subapertures across the pupil of the telescope, allowing for wavefront reconstruction up to the fifth radial Zernike order. We find that the wavefront aberration in each star can be roughly halved by subtracting the average of the wavefronts from the other three stars. Wavefront correction on this basis leads to a reduction in width of the seeing-limited stellar image by up to a factor of 3, with image sharpening effective from the visible to near infrared wavelengths over a field of at least 2 arc minutes. We conclude that GLAO correction will be a valuable tool that can increase resolution and spectrographic throughput across a broad range of seeing-limited observations.Comment: 25 pages, 8 figures, to be published in Astrophys.

Athena\u27s Prism - A Diplomatic Strategy Role Playing Simulation for Generating Ideas and Exploring Alternatives

Intelligence analysts must clear at least three hurdles to get good product out the door: cognitive biases, social biases and self-imposed organizational impediments. Others (e.g., Gilovich, et al., Heuer, and Kahneman and Tversky), explain the cognitive processes that can help or trip us. A less well mapped set of dangers arises in the social dynamics of communicating tasking, working with other analysts, editing and customer interaction. Finally, the mere fact of a unit\u27s published record creates analytic inertia - an argument at rest tends to stay at rest and one in motion (i.e., ambiguous or uncertain) tends to stay in motion. (A variation of this includes groupthink.

MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching microorganisms

Heap bioleaching performance is dependent on the contacting of the leach solution with the ore bed, hence on the system hydrodynamics. In this study two experimental setups were used to examine hydrodynamics associated with irrigation from a single drip emitter, one of the most common methods of heap irrigation. A specialist magnetic resonance imaging (MRI) method which is insensitive to the metal content of the ore was used to examine the liquid flow into an ore bed in the immediate vicinity of an irrigation point. The distribution of liquid in, microbial colonisation of and mineral recovery from a bioleach of a large scale 132 kg “ore slice” were subsequently monitored using sample ports positioned along the breadth and height of the reactor. In both systems the lateral movement of the liquid increased with bed depth, though preferential flow was evident. The majority of the liquid flow was in the region directly below the irrigation point and almost no liquid exchange occurred in the areas of lowest liquid content at the upper corners of the bed in which fluid exchange was driven by capillary action. The MRI studies revealed that the liquid distribution was unchanging following an initial settling of the ore bed and that, at steady state, the majority (~60%) of the liquid flowed directly into established large channels. The limited lateral movement of the liquid had a significant impact on the local leaching efficiencies and microbial colonisation of the ore with cell concentrations in the regions of lowest liquid content lying below the detection limit. Hence poor lateral liquid distribution with drip irrigation, and the associated impact on colonisation was identified as a significant disadvantage of this irrigation approach. Further, the need to optimise fluid exchange throughout the ore bed was identified as key for optimisation of leaching performance