Laser-induced transient magnons in Sr3Ir2O7 throughout the Brillouin zone.

Although ultrafast manipulation of magnetism holds great promise for new physical phenomena and applications, targeting specific states is held back by our limited understanding of how magnetic correlations evolve on ultrafast timescales. Using ultrafast resonant inelastic X-ray scattering we demonstrate that femtosecond laser pulses can excite transient magnons at large wavevectors in gapped antiferromagnets and that they persist for several picoseconds, which is opposite to what is observed in nearly gapless magnets. Our work suggests that materials with isotropic magnetic interactions are preferred to achieve rapid manipulation of magnetism.

Integrating Navajo Pottery Techniques To Improve Silver Nanoparticle-Enabled Ceramic Water Filters for Disinfection.

Point-of-use treatment technologies can increase access to safe drinking water in rural areas. Sustained use of these technologies is uncommon due to oversight of community needs, user-perceived risks, long-term maintenance, and conflict with traditional practices. Nanosilver-enabled ceramic water filters are unique due to the use of locally sourced materials available at or near the target community; however, technical limitations persist (e.g., nanosilver's uncontrolled release and passivation from sulfide or chloride). This work aims to overcome these limitations by impregnating nanosilver onto ceramics with a Navajo pottery rosin, collected from pinyon trees with a third-generation artisan. Here, we investigate this sustainable and novel material for drinking water treatment; the study ranges from a proof of concept to testing under realistic conditions. Results show that when embedded in a thin film, the biopolymer controlled ionic silver dissolution and prevented silver passivation from sulfide and chloride. When applied to ceramic filters, the biopolymer effectively immobilized nanosilver in a range of waters. Over a 25 day study to emulate household-use conditions, this coating method sustained disinfection of a coculture of Gram-positive and Gram-negative bacteria while controlling biofouling. Overall, the use of this Navajo pottery material can facilitate adoption while providing the needed technological advancement to these widely used treatment devices.

Protozoan-Priming and Magnesium Conditioning Enhance Legionella pneumophila Dissemination and Monochloramine Resistance.

Opportunistic pathogens (OPs) are of concern in drinking water distribution systems because they persist despite disinfectant residuals. While many OPs garner protection from disinfectants via a biofilm lifestyle, Legionella pneumophila (Lp) also gains disinfection resistance by being harbored within free-living amoebae (FLA). It has been long established, but poorly understood, that Lp grown within FLA show increased infectivity toward subsequent FLA or human cells (i.e., macrophage), via a process we previously coined "protozoan-priming". The objectives of this study are (i) to identify in Lp a key genetic determinant of how protozoan-priming increases its infectivity, (ii) to determine the chemical stimulus within FLA to which Lp responds during protozoan-priming, and (iii) to determine if more infectious forms of Lp also exhibit enhanced disinfectant resistance. Using Acanthamoeba castellanii as a FLA host, the priming effect was isolated to Lp's sidGV locus, which is activated upon sensing elevated magnesium concentrations. Supplementing growth medium with 8 mM magnesium is sufficient to produce Lp grown in vitro with an infectivity equivalent to that of Lp grown via the protozoan-primed route. Both Lp forms with increased infectivity (FLA-grown and Mg2+-supplemented) exhibit greater monochloramine resistance than Lp grown in standard media, indicating that passage through FLA not only increases Lp's infectivity but also enhances its monochloramine resistance. Therefore, laboratory-based testing of disinfection strategies should employ conditions that simulate or replicate intracellular growth to accurately assess disinfectant resistance.

A Structural Equation Model to Decipher Relationships among Water, Sanitation, and Health in Colonias-Type Unincorporated Communities.

The colonias along the United States-Mexico border are generally self-built neighborhoods of low-income families that lack basic infrastructure. While some government assistance has provided roads and electricity, water and wastewater services are still lacking in many colonias. This research is the first to collect a comprehensive dataset on water, sanitation, health, and living conditions in these unincorporated neighborhoods through collection of water samples and surveys; 114 households in 23 colonias across three geographically diverse Texas counties are studied. Water quality is assessed via traditional microbial indicators, chlorine, and arsenic. This complex dataset requires an advanced statistical tool to disentangle relationships among diverse factors. Structural equation modeling is utilized to identify relationships among surveyed and measured variables. The model reveals that colonias residents with well/hauled water accurately predict their water quality, while those with treated+piped water tend to think that their water is worse than it actually is. Dwelling quality and connection to sanitary sewers influence perceived health risks and household health, respectively. Furthermore, these communities have an overwhelming need and desire for point-of-use water treatment. This model can inform decision making and may be adapted to probe other questions and social dynamics for water and sanitation in unincorporated communities elsewhere.

Resonant inelastic X-ray scattering of magnetic excitations under pressure.

Resonant inelastic X-ray scattering (RIXS) is an extremely valuable tool for the study of elementary, including magnetic, excitations in matter. The latest developments of this technique have mostly been aimed at improving the energy resolution and performing polarization analysis of the scattered radiation, with a great impact on the interpretation and applicability of RIXS. Instead, this article focuses on the sample environment and presents a setup for high-pressure low-temperature RIXS measurements of low-energy excitations. The feasibility of these experiments is proved by probing the magnetic excitations of the bilayer iridate Sr3Ir2O7 at pressures up to 12 GPa.

Intraoperative TOE guided management of newly diagnosed severe tricuspid regurgitation and pulmonary hypertension during orthotopic liver transplantation: a case report demonstrating the importance of reversibility as a favorable prognostic factor.

BACKGROUND: Tricuspid regurgitation (TR) and pulmonary hypertension (PHT) are highly dynamic cardiovascular lesions that may progress rapidly, particularly in the orthotopic liver transplantation (OLT) waitlist population. Severe TR and PHT are associated with poor outcomes in these patients, however it is rare for the two to be newly diagnosed intraoperatively at the time of OLT. Without preoperative information on pulmonary vascular and right heart function, the potential for reversibility of severe TR and PHT is unclear, making the decision to proceed to transplant fraught with difficulty. CASE PRESENTATION: We present a case of successful orthotopic liver transplantation (OLT) in a 48 year old female with severe (PHT) (mean pulmonary arterial pressure > 55 mmHg) and severe TR diagnosed post induction of anaesthesia. The degree of TR was associated with systemic venous pressures of > 100 mmHg resulting in massive haemorrhage during surgery and difficulty in distinguishing venous from arterial placement of vascular access devices. Intraoperative transoesophageal echocardiography (TOE) proved crucial in diagnosing functional TR due to tricuspid annular and right ventricular (RV) dilatation, and dynamically monitoring response to treatment. In response to positioning, judicious volatile anaesthesia administration, pulmonary vasodilator therapy and permissive hypovolemia during surgery we noted substantial improvement of the TR and pulmonary arterial pressures, confirming the reversibility of the TR and associated PHT. CONCLUSION: TR and PHT are co-dependent, dynamic, load sensitive right heart conditions that are interdependent with chronic liver disease, and may progress rapidly in patients waitlisted for OLT. Use of intraoperative TOE and pulmonary artery catheterisation on the day of surgery will detect previously undiagnosed severe TR and PHT, enable rapid assessment of the cause and the potential for reversibility. These dynamic monitors permit real-time assessment of the response to interventions or events affecting right ventricular (RV) preload and afterload, providing critical information for prognosis and management. Furthermore, we suggest that TR and PHT should be specifically sought when waitlisted OLT patients present with hepatic decompensation.

Laccase removal of 2-chlorophenol and sulfamethoxazole in municipal wastewater.

Laccases were studied for their ability to remove two compounds, 2-chlorophenol and sulfamethoxazole, in batch studies, both in buffered solutions and in wastewater samples from different points in a municipal water resource recovery facility. Two enzymes with and without a mediator (acetosyringone) were investigated: a commercial product derived from Myceliphthora thermophile and a laboratory-generated enzyme mix derived from Tramates versicolor. The chlorophenol was removed rapidly by the commercial enzyme in the presence of acetosyringone, but the primary products were coupling complexes of the reactants. Excellent removal was achieved without acetosyringone by the natural enzyme mix. Sulfamethoxazole was poorly removed in all laboratory-generated chemically buffered solutions, but was very well removed, without the addition of mediators, in secondary effluent suspensions from a municipal water resource recovery facility. Mechanistic studies are still required, but the results suggest that treatment via direct addition of enzymes is feasible to remove recalcitrant compounds in municipal wastewater.

DLVO Approximation Methods for Predicting the Attachment of Silver Nanoparticles to Ceramic Membranes.

This article examines the influence of three common stabilizing agents (citrate, poly(vinylpyrrolidone) (PVP), and branched poly(ethylenimine) (BPEI)) on the attachment affinity of silver nanoparticles to ceramic water filters. Citrate-stabilized silver nanoparticles were found to have the highest attachment affinity (under conditions in which the surface potential was of opposite sign to the filter). This work demonstrates that the interaction between the electrical double layers plays a critical role in the attachment of nanoparticles to flat surfaces and, in particular, that predictions of double-layer interactions are sensitive to boundary condition assumptions (constant charge vs constant potential). The experimental deposition results can be explained when using different boundary condition assumptions for different stabilizing molecules but not when the same assumption was assumed for all three types of particles. The integration of steric interactions can also explain the experimental deposition results. Particle size was demonstrated to have an effect on the predicted deposition for BPEI-stabilized particles but not for PVP.

Incentivizing Decentralized Sanitation: The Role of Discount Rates.

In adoption decisions for decentralized sanitation technologies, two decision makers are involved: the public utility and the individual homeowner. Standard life cycle cost is calculated from the perspective of the utility, which uses a market-based discount rate in these calculations. However, both decision-makers must be considered, including their differing perceptions of the time trade-offs inherent in a stream of costs and benefits. This study uses the discount rate as a proxy for these perceptions and decision-maker preferences. The results in two case studies emphasize the dependence on location of such analyses. Falmouth, Massachusetts, appears to be a good candidate for incentivizing decentralized sanitation while the Allegheny County Sanitary Authority service area in Pennsylvania appears to have no need for similar incentives. This method can be applied to any two-party decision in which the parties are expected to have different discount rates.

Clinical evaluation of a novel technology for non-invasive and continuous measurement of plasma haemoglobin concentration.

We undertook the first clinical evaluation of a novel, non-invasive device for the continuous measurement of plasma haemoglobin concentration in 25 patients undergoing elective cardiac surgery. At four pre-determined intervals, samples of blood were taken for plasma haemoglobin estimation on a blood gas analyser and a laboratory device and were compared with the plasma haemoglobin estimation on the novel device using the Bland-Altman method. The 95% limits of agreement for estimation of plasma haemoglobin concentration for the device vs. laboratory, the device vs. the blood gas analyser and the blood gas analyser vs. the laboratory were 101.3 g.l(-1) , 103.1 g.l(-1) and 14.5 g.l(-1) , respectively. The bias (mean difference) in each case was 27.4 g.l(-1) , 25.1 g.l(-1) and 2.4 g.l(-1) , respectively. We conclude that the novel device in its current form is not a suitable replacement for more invasive methods of determining plasma haemoglobin concentration in patients in the setting of cardiac surgery; however, lessons learnt from the study will help to improve the device's future performance.

Comprehensive understanding of nano-sized particle separation processes using nanoparticle tracking analysis.

The understanding of nano-sized particle separation processes has been limited by difficulties of nanoparticle characterization. In this study, nanoparticle tracking analysis (NTA) was deployed to evaluate the absolute particle size distributions in laboratory scale flocculation and filtration experiments with silver nanoparticles. The results from NTA were consistent with standard theories of particle destabilization and transport. Direct observations of changes in absolute particle size distributions from NTA enhance both qualitative and quantitative understanding of particle separation processes of nano-sized particles.

Salmonella meningitis and septicaemia in an non-immunocompromised adult, associated with a cluster of Salmonella Enteritidis PT 14b, Ireland, November 2009.

We report a fatal case of meningitis caused by Salmonella Enteritidis phage type 14b in a middle-aged man who had no history or findings to suggest he was immunocompromised. To our knowledge, this is the first reported case of Salmonella meningitis in an adult in Ireland, and the first case of meningitis in an adult caused by phage type 14b. This case was associated with a nationwide cluster of salmonellosis which is still under investigation at the time of writing.

Designing Solute-Tailored Selectivity in Membranes: Perspectives for Water Reuse and Resource Recovery.

Treatment of nontraditional source waters (e.g., produced water, municipal and industrial wastewaters, agricultural runoff) offers exciting opportunities to expand water and energy resources via water reuse and resource recovery. While conventional polymer membranes perform water/ion separations well, they do not provide solute-specific separation, a key component for these treatment opportunities. Herein, we discuss the selectivity limitations plaguing all conventional membranes, which include poor removal of small, neutral solutes and insufficient discrimination between ions of the same valence. Moreover, we present synthetic approaches for solute-tailored selectivity including the incorporation of single-digit nanopores and solute-selective ligands into membranes. Recent progress in these areas highlights the need for fundamental studies to rationally design membranes with selective moieties achieving desired separations.

Seasonal contamination of well-water in flood-prone colonias and other unincorporated U.S. communities.

Many of the six million residents of unincorporated communities in the United States depend on well-water to meet their needs. One group of unincorporated communities is the colonias, located primarily in several southwestern U.S. states. Texas is home to the largest number of these self-built communities, of mostly low-income families, lacking basic infrastructure. While some states have regulations that mandate minimum infrastructure for these communities, water and sewage systems are still lacking for many of their residents. Unprotected wells and self-built septic/cesspool systems serve as the primary infrastructure for many such colonias. This research was designed to probe how wells and septic/cesspool systems are influenced by heavy rainfall events. Such events are hypothesized to impact water quality with regard to human health. Inorganic and microbiological water quality of the wells in nine colonias located in Nueces County, Texas, were evaluated during dry and wet periods. Nueces County was selected as an example based on its flooding history and the fact that many colonias there depend entirely on well-water and septic/cesspool systems. The results demonstrate that well-water quality in these communities varies seasonally with respect to arsenic (up to 35 µg/L) and bacterial contamination (Escherichia coli), dependent on the amount of rainfall, which leaves this population vulnerable to health risks during both wet and dry periods. Microbial community analyses were also conducted on selected samples. To explore similar seasonal contamination of well-water, an analysis of unincorporated communities, flooding frequency, and arsenic contamination in wells was conducted by county throughout the United States. This nationwide analysis indicates that unincorporated communities elsewhere in the United States are likely experiencing comparable challenges for potable water access because of a confluence of socioeconomic, infrastructural, and policy realities.

Water Treatment: Are Membranes the Panacea?

Alongside the rising global water demand, continued stress on current water supplies has sparked interest in using nontraditional source waters for energy, agriculture, industry, and domestic needs. Membrane technologies have emerged as one of the most promising approaches to achieve water security, but implementation of membrane processes for increasingly complex waters remains a challenge. The technical feasibility of membrane processes replacing conventional treatment of alternative water supplies (e.g., wastewater, seawater, and produced water) is considered in the context of typical and emerging water quality goals. This review considers the effectiveness of current technologies (both conventional and membrane based), as well as the potential for recent advancements in membrane research to achieve these water quality goals. We envision the future of water treatment to integrate advanced membranes (e.g., mixed-matrix membranes, block copolymers) into smart treatment trains that achieve several goals, including fit-for-purpose water generation, resource recovery, and energy conservation.

Particle size distribution dynamics during precipitative softening: declining solution composition.

Particle removal is a critical step in the treatment of surface water for potable use, and the majority of drinking water treatment plants employ precipitative coagulation processes such as alum and iron "sweep-floc" coagulation or lime softening for particle pre-treatment. Unfortunately, little is quantitatively known about how particle size distributions are shaped by simultaneous precipitation and flocculation. In an earlier paper, we demonstrated the effects of the saturation ratio, the mixing intensity and the seed concentration on the rates of homogeneous nucleation, precipitative growth and flocculation during precipitation of calcium carbonate at constant solution composition using electronic particle counting techniques. In this work, we extend those findings to systems more closely emulating the conditions in actual softening processes (i.e., declining solution composition). Key findings include the strong dependence of the rate of flocculation on the initial saturation ratio and demonstration of the benefits of seeding precipitative softening from the perspective of optimizing the effluent particle size distribution. The mixing intensity during precipitation was also shown to strongly influence the final particle size distribution. Implications of the findings with respect to softening practice are discussed.

Reverse osmosis desalination: water sources, technology, and today's challenges.

Reverse osmosis membrane technology has developed over the past 40 years to a 44% share in world desalting production capacity, and an 80% share in the total number of desalination plants installed worldwide. The use of membrane desalination has increased as materials have improved and costs have decreased. Today, reverse osmosis membranes are the leading technology for new desalination installations, and they are applied to a variety of salt water resources using tailored pretreatment and membrane system design. Two distinct branches of reverse osmosis desalination have emerged: seawater reverse osmosis and brackish water reverse osmosis. Differences between the two water sources, including foulants, salinity, waste brine (concentrate) disposal options, and plant location, have created significant differences in process development, implementation, and key technical problems. Pretreatment options are similar for both types of reverse osmosis and depend on the specific components of the water source. Both brackish water and seawater reverse osmosis (RO) will continue to be used worldwide; new technology in energy recovery and renewable energy, as well as innovative plant design, will allow greater use of desalination for inland and rural communities, while providing more affordable water for large coastal cities. A wide variety of research and general information on RO desalination is available; however, a direct comparison of seawater and brackish water RO systems is necessary to highlight similarities and differences in process development. This article brings to light key parameters of an RO process and process modifications due to feed water characteristics.

The impact of diving on hearing: a 10-25 year audit of New Zealand professional divers.

INTRODUCTION: Surveillance of professional divers' hearing is routinely undertaken on an annual basis despite lack of evidence of benefit to the diver. The aim of this study was to determine the magnitude and significance of changes in auditory function over a 10-25 year period of occupational diving with the intention of informing future health surveillance policy for professional divers. METHODS: All divers with adequate audiological records spanning at least 10 years were identified from the New Zealand occupational diver database. Changes in auditory function over time were compared with internationally accepted normative values. Any significant changes were tested for correlation with diving exposure, smoking history and body mass index. RESULTS: The audiological records of 227 professional divers were analysed for periods ranging from 10 to 25 years. Initial hearing was poorer than population norms, and deterioration over the observation period was less than that predicted by normative data. Changes in hearing were not related to diving exposure, or smoking history. CONCLUSION: Audiological changes over 10 to 25 years of occupational diving were not found to be significantly different from age-related changes. Routine annual audiological testing of professional divers does not appear to be justifiable.

Transformation kinetics of cyclophosphamide and ifosfamide by ozone and hydroxyl radicals using continuous oxidant addition reactors.

The detection of pharmaceuticals in water and wastewater has triggered human and ecological health concerns. As highly toxic compounds, chemotherapy agents (CAs), such as the cyclophosphamide (CYP) and ifosfamide (IFO) structural isomers, represent a unique threat. This research elucidated the fate of CYP and IFO during ozonation and advanced oxidation by hydroxyl radicals (HO•). Novel semi-batch reactors were used to determine the second-order rate constants for CYP and IFO with O3 and HO•. These reactors provided independent control of the oxidant exposure through continuous and constant aqueous ozone and peroxone (O3-H2O2) addition. The rate constants for transformation of CYP and IFO by ozone were 2.58 ± 0.40 M-1s-1 and 6.95 ± 0.21 M-1s-1, respectively, indicating that ozone alone is not suitable for treating CAs. Transformation of CYP and IFO by hydroxyl radicals was fast, with rate constants of 2.69(±0.17)×109 M-1s-1 and 2.73(±0.16)×109 M-1s-1, respectively. The major transformation products formed by O3 and HO attack consisted of the 4-hydroxy-, 4-keto-, dechloroethyl-, and imino- derivatives of CYP and IFO. Low yields of the active metabolites of the CAs, namely phosphoramide mustard and isophosphoramide mustard, were detected. These findings suggest that treated water may retain the ability to alkylate DNA and confer toxicity.

The impact of health on professional diver attrition.

INTRODUCTION: Approximately 77% of professional divers leave the industry within five years of entry, for reasons that are uncertain. One possibility is that attrition is due to ill-health. The health of New Zealand occupational divers is surveyed by a comprehensive medical examination every five years and by a health questionnaire in the intervening years. Divers are thereby confirmed 'fit' annually. The aim of this study was to determine if divers quit the industry due to a health problem not identified by this health surveillance system. METHOD: 601 divers who had left the industry within five years of entry medical examination ('quitters') were identified from a computerised database. One hundred and thirty-six who could be contacted were questioned about their principal reason for quitting. Comparison was made between the health data of all those defined as 'quitters' and a group of 436 'stayers' who have remained active in the industry for over 10 years. RESULTS: Health was the principal reason for abandoning a diving career for only 2.9% of quitters. The overwhelming majority (97.1%) quit because of dissatisfaction with aspects of the work, such as remuneration and reliability of employment. Besides gender, the only significant difference between the health data of quitters and stayers was that smoking was four times more prevalent among quitters. CONCLUSIONS: The key determinant of early attrition from the New Zealand professional diver workforce is industry-related rather than health-related. The current New Zealand diver health surveillance system detects the medical problems that cause divers to quit the industry.