Silver and Copper Nitride Cooperate for CO Electroreduction to Propanol

The need of carbon sources for the chemical industry, alternative to fossil sources, has pointed to CO2 as a possible feedstock. While CO2 electroreduction (CO2 R) allows production of interesting organic compounds, it suffers from large carbon losses, mainly due to carbonate formation. This is why, quite recently, tandem CO2 R, a two-step process, with first CO2 R to CO using a solid oxide electrolysis cell followed by CO electroreduction (COR), has been considered, since no carbon is lost as carbonate in either step. Here we report a novel copper-based catalyst, silver-doped copper nitride, with record selectivity for formation of propanol (Faradaic efficiency: 45 %), an industrially relevant compound, from CO electroreduction in gas-fed flow cells. Selective propanol formation occurs at metallic copper atoms derived from copper nitride and is promoted by silver doping as shown experimentally and computationally. In addition, the selectivity for C2+ liquid products (Faradaic efficiency: 80 %) is among the highest reported so far. These findings open new perspectives regarding the design of catalysts for production of C3 compounds from CO2 .

Metal Core-Shell Nanoparticle Supercrystals: From Photoactivation of Hydrogen Evolution to Photocorrosion

Gas nanobubbles are directly linked to many important chemical reactions. While they can be detrimental to operational devices, they also reflect the local activity at the nanoscale. Here, supercrystals made of highly monodisperse Ag@Pt core-shell nanoparticles are first grown onto a solid support and fully characterized by electron microscopies and X-ray scattering. Supercrystals are then used as a plasmonic photocatalytic platform for triggering the hydrogen evolution reaction. The catalytic activity is measured operando at the single supercrystal level by high-resolution optical microscopy, which allows gas nanobubble nucleation to be probed at the early stage with high temporal resolution and the amount of gas molecules trapped inside them to be quantified. Finally, a correlative microscopy approach and high-resolution electron energy loss spectroscopy help to decipher the mechanisms at the origin of the local degradation of the supercrystals during catalysis, namely nanoscale erosion and corrosion.

Design and Modification of a Material Extrusion 3D Printer to Manufacture Functional Gradient PEEK Components

In recent years, the creative use of polymers has been expanded as the range of achievable material properties and options for manufacturing and post-processing continually grows. The main goal of this research was to design and develop a fully-functioning material extrusion additive manufacturing device with the capability to produce functionally graded high-temperature thermoplastic PEEK (polyether ether ketone) materials through the manipulation of microstructure during manufacturing. Five different strategies to control the chamber temperature and crystallinity were investigated, and concepts of thermal control were introduced to govern the crystallisation and cooling mechanics during the extrusion process. The interaction of individually deposited beads of material during the printing process was investigated using scanning electron microscopy to observe and quantify the porosity levels and interlayer bonding strength, which affect the quality of the final part. Functional testing of the printed parts was carried out to identify crystallinity, boundary layer adhesion, and mechanical behaviour. Furnace cooling and annealing were found to be the most effective methods, resulting in the highest crystallinity of the part. Finally, a functionally graded material cylindrical part was printed successfully, incorporating both low and high crystalline regions.

Season at the time of oocyte collection and frozen embryo transfer outcomes

STUDY QUESTION

Does the meteorological season at the time of oocyte retrieval affect live birth rates in subsequent frozen embryo transfers?

SUMMARY ANSWER

Frozen embryo transfers resulting from oocytes retrieved in summer have 30% increased odds of live birth compared to frozen embryo transfers resulting from oocytes retrieved in autumn, regardless of the season at the time of embryo transfer.

WHAT IS KNOWN ALREADY

Season at the time of frozen embryo transfer does not appear to be associated with live birth rate. One study in the northern hemisphere found increased odds of live birth with frozen embryo transfer resulting from oocytes collected in summer when compared to those collected in winter.

STUDY DESIGN, SIZE, DURATION

Retrospective cohort study including all frozen embryo transfers performed by a single clinic over eight years, from January 2013 to December 2021. There were 3659 frozen embryo transfers with embryos generated from 2155 IVF cycles in 1835 patients. Outcome data were missing for two embryo transfers, which were excluded from analysis. Outcomes were analysed by the season, temperatures, and measured duration of sunshine at the time of oocyte collection and at the time of frozen embryo transfer.

PARTICIPANTS/MATERIALS, SETTING, METHODS

There were no significant differences between patients with oocyte collection or embryo transfers in different seasons. Meteorological conditions on the day of oocyte collection and the day of frozen embryo transfer, and in the preceding 14- and 28-day periods, were collected including mean, minimum, and maximum temperatures, and recorded duration of sunshine hours. Clinical and embryological outcomes were analysed for their association with seasons, temperatures, and duration of sunshine with correction for repeated cycles per participant, age at the time of oocyte retrieval, and quadratic age.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared to frozen embryo transfers with oocyte retrieval dates in autumn, transfers with oocyte retrieval dates in summer had 30% increased odds of live birth (odds ratio (OR): 1.30, 95% CI: 1.04-1.62) which remained consistent after adjustment for season at the time of embryo transfer. A high duration of sunshine hours (in the top tertile) on the day of oocyte retrieval was associated with a 28% increase in odds of live birth compared to duration of sunshine hours in the lowest tertile (OR 1.28, 95% CI: 1.06-1.53). Temperature on the day of oocyte retrieval did not independently affect the odds of live birth. The odds of live birth were decreased by 18% when the minimum temperature on the day of embryo transfer was high, compared with low (OR: 0.82, 95% CI: 0.69-0.99), which was consistent after correction for the conditions at the time of oocyte retrieval.

LIMITATIONS, REASONS FOR CAUTION

This was a retrospective cohort study, however, all patients during the study period were included and data was missing for only two patients. Given the retrospective nature, causation is not proven and there are other factors that may affect live birth rates and for which we did not have data and were unable to adjust, including pollutants and behavioural factors. We were also not able to stratify results based on specific patient populations (such as poor- or hyper-responders) nor report the cumulative live birth rate per commenced cycle.

WIDER IMPLICATIONS OF THE FINDINGS

These findings may be particularly relevant for patients planning oocyte or embryo cryopreservation. Given the increasing utilization of cryopreservation, identification of factors that influence outcomes in subsequent frozen embryo transfers has implications for future therapeutic and management options. Further studies to clarify the physiology underlying the influence of sunshine hours or season on subsequent frozen embryo transfer outcomes are required, including identification of specific populations that may benefit from these factors.

STUDY FUNDING/COMPETING INTERESTS

No funding was provided for this study. S.L. has received educational travel assistance from Besins, Merck and Organon outside the submitted work. R.H. is National Medical Director of City Fertility and Medical Director of Fertility Specialists of Western Australia, has received honoraria from MSD, Merck Serono, Origio and Ferring outside the submitted work, and has equity interests in CHA SMG. C.R., M.W., and E.N. declare that they have no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Advancements in Functionally Graded Polyether Ether Ketone Components: Design, Manufacturing, and Characterisation Using a Modified 3D Printer

Functionally Graded Materials represent the next generation of engineering design for metal and plastic components. In this research, a specifically modified and optimised 3D printer was used to manufacture functionally graded polyether ether ketone components. This paper details the design and manufacturing methodologies used in the development of a polyether ether ketone printer capable of producing functionally graded materials through the manipulation of microstructure. The interaction of individually deposited beads of material during the printing process was investigated using scanning electron microscopy, to observe and quantify the porosity levels and interlayer bonding strength, which affects the quality of the final parts. Specimens were produced under varying process conditions and tested to characterise the influence of the process conditions on the resulting material properties. The specimens printed at high enclosure temperatures exhibited greater strength than parts printed without the active addition of heat, due to improved bond formation between individual layers of the print and a large degree of crystallinity through maintenance at these elevated temperatures.

Precision Medicine Approach for Cardiometabolic Risk Factors in Therapeutic Apheresis

Lipoprotein apheresis (LA) is currently the most powerful intervention possible to reach a maximal reduction of lipids in patients with familial hypercholesterolemia and lipoprotein(a) hyperlipidemia. Although LA is an invasive method, it has few side effects and the best results in preventing further major cardiovascular events. It has been suggested that the highly significant reduction of cardiovascular complications in patients with severe lipid disorders achieved by LA is mediated not only by the potent reduction of lipid levels but also by the removal of other proinflammatory and proatherogenic factors. Here we performed a comprehensive proteomic analysis of patients on LA treatment using intra-individually a set of differently sized apheresis filters with the INUSpheresis system. This study revealed that proteomic analysis correlates well with routine clinical chemistry in these patients. The method is eminently suited to discover new biomarkers and risk factors for cardiovascular disease in these patients. Different filters achieve reduction and removal of proatherogenic proteins in different quantities. This includes not only apolipoproteins, C-reactive protein, fibrinogen, and plasminogen but also proteins like complement factor B (CFAB), protein AMBP, afamin, and the low affinity immunoglobulin gamma Fc region receptor III-A (FcγRIIIa) among others that have been described as atherosclerosis and metabolic vascular diseases promoting factors. We therefore conclude that future trials should be designed to develop an individualized therapy approach for patients on LA based on their metabolic and vascular risk profile. Furthermore, the power of such cascade filter treatment protocols may improve the prevention of cardiometabolic disease and its complications.

Testing of hydrophobically coated composite materials with marine energy applications

Tidal turbine applications will place composite materials such as glass-fibre-reinforced polymers (GFRPs) and carbon-fibre-reinforced polymers under surprisingly high pressure due to the significant water depths they operate in (to depths of 50 m). The technical reliability of tidal turbines must be guaranteed despite the high dynamic loads resulting from the combination of plant operation, wind and waves with irregular swell. These external effects could lead to operation downtime and accelerated degradation. Research has already established that (unpressurised) moisture saturation is detrimental to both the tensile and fatigue strengths of a GFRP material compared with its dry laminate performance. This degradation has been shown to be stress dependent. It is possible that hydrophobic coatings could help protect the material while in service. Therefore, two commercially available coatings were applied to five variations of composite materials. These materials are commonly used in tidal and wave turbine blades, as they have excellent corrosion resistance and mechanical properties. All five were subjected to the same conditioning processes: non-pressurised and pressurised immersion conditioning in water. A glass-fibre epoxy (Ampreg) composite, along with a glass-fibre powdered epoxy composite, a glass-fibre polyether ether ketone composite and a carbon-fibre powdered epoxy composite, was investigated. The glass-fibre epoxy (Ampreg) was also subjected to static/fatigue tensile tests.

Versatile and robust synthesis process for the fine control of the chemical composition and core-crystallinity of spherical core-shell Au@Ag nanoparticles

Au nanoparticles (NPs) characterized by distinct surface chemistry (including dodecanethiol or oleylamine as capping agent), different sizes (∼5 and ∼10 nm) and crystallinities (polycrystalline or single crystalline), were chosen as seeds to demonstrate the versatility and robustness of our two-step core-shell Au@Ag NP synthesis process. The central component of this strategy is to solubilize the shell precursor (AgNO₃) in oleylamine and to induce the growth of the shell on selected seeds under heating. The shell thickness is thus controlled by the temperature, the annealing time, the (shell precursor)/(seed) concentration ratio, seed size and crystallinity. The shell thickness is thus shown to increase with the reactant concentration and to grow faster on polycrystalline seeds. The crystalline structure and chemical composition were characterized by HRTEM, STEM-HAADF, EELS and Raman spectroscopy. The plasmonic response of Au@Ag core-shell NPs as a function of core size and shell thickness was assessed by spectrophotometry and simulated by calculations based on the discrete dipole approximation (DDA) method. Finally, the nearly monodisperse core-shell Au@Ag NPs were shown to form micrometer-scale facetted 3D fcc-ordered superlattices (SLs) after solvent evaporation and deposition on a solid substrate. These SLs are promising candidates for applications as a tunable surface-enhanced Raman scattering platform.

Inert gas bubble formation in magnetron sputtered thin-film CdTe solar cells

Cadmium telluride (CdTe) solar cells are deposited in current production using evaporation-based tech- niques. Fabricating CdTe solar cells using magnetron sputtering would have the advantage of being more cost-efficient. Here, we show that such deposition results in the incorporation of the magnetron working gas Ar, within the films. Post deposition processing with CdCl2 improves cell efficiency and during which stacking faults are removed. The Ar then accumulates into clusters leading to the creation of voids and blisters on the surface. Using molecular dynamics, the penetration threshold energies are determined for both Ar and Xe, with CdTe in both zinc-blende and wurtzite phases. These calculations show that more Ar than Xe can penetrate into the growing film with most penetration across the (111) surface. The mechanisms and energy barriers for interstitial Ar and Xe diffusion in zinc-blende are determined. Barriers are reduced near existing clusters, increasing the probability of capture-based cluster growth. Barriers in wurtzite are higher with non-Arrhenius behaviour observed. This provides an explanation for the increase in the size of voids observed after stacking fault removal. Blister exfoliation was also modelled, showing the formation of shallow craters with a raised rim.

Nanoscale Analysis of Randall's Plaques by Electron Energy Loss Spectromicroscopy: Insight in Early Biomineral Formation in Human Kidney

Idiopathic kidney stones originate mainly from calcium phosphate deposits at the tip of renal papillae, known as Randall's plaques (RPs), also detected in most human kidneys without stones. However, little is known about the mechanisms involved in RP formation. The localization and characterization of such nanosized objects in the kidney remain a real challenge, making their study arduous. This study provides a nanoscale analysis of the chemical composition and morphology of incipient RPs, characterizing in particular the interface between the mineral and the surrounding organic compounds. Relying on data gathered from a calculi collection, the morphology and chemical composition of incipient calcifications in renal tissue were determined using spatially resolved electron energy-loss spectroscopy. We detected microcalcifications and individual nanocalcifications found at some distance from the larger ones. Strikingly, concerning the smaller ones, we show that two types of nanocalcifications coexist: calcified organic vesicles and nanometric mineral granules mainly composed of calcium phosphate with carbonate in their core. Interestingly, some of these nanocalcifications present similarities with those reported in physiological bone or pathological cardiovascular biominerals, suggesting possible common formation mechanisms. However, the high diversity of these nanocalcifications suggests that several mechanisms may be involved (nucleation on a carbonate core or on organic compounds). In addition, incipient RPs also appear to present specific features at larger scales, revealing secondary calcified structures embedded in a fibrillar organic material. Our study proves that analogies exist between physiological and pathological biominerals and provides information to understand the physicochemical processes involved in pathological calcification formation.

A novel 96.5Sn3Cu0.5Mn nanosolder with enhanced wettability applied to nanosoldering of WO3 nanomaterial

Nano-soldering relying on a sacrificial nanosolder, is a flexible interconnection technique, having promising applications in joining nanosized functional materials; that is an essential step in the assembly of nano-devices. In a soldering, the wettability is important in the bonding of two nanomaterial, which determines the quality of the junction. Tungsten trioxide nanomaterial has unique characteristics such as electro-, opto-, gaso-chromic. To assemble this nanomaterial into functional nano-devices, a superior nanosolder is necessary. The conventional SnCu nanosolder has been chosen, but its wetting on WO₃ is unsatisfactory. Here, our study indicates that the SnCu wettability on WO₃ material has been improved greatly by adding minor manganese, in which the contact angle has a significant change from 73.2° to 41.7°. Then the wetting mechanism is investigated by observing the soldering interface. Lastly, a more robust and higher-reliable junction has been obtained by thermal soldering two individual WO₃ nano-objects into a cross-shaped pattern.

Engineering Transport in Manganites by Tuning Local Nonstoichiometry in Grain Boundaries

Interface-dominated materials such as nanocrystalline thin films have emerged as an enthralling class of materials able to engineer functional properties of transition metal oxides widely used in energy and information technologies. In particular, it has been proven that strain-induced defects in grain boundaries of manganites deeply impact their functional properties by boosting their oxygen mass transport while abating their electronic and magnetic order. In this work, the origin of these dramatic changes is correlated for the first time with strong modifications of the anionic and cationic composition in the vicinity of strained grain boundary regions. We are also able to alter the grain boundary composition by tuning the overall cationic content in the films, which represents a new and powerful tool, beyond the classical space charge layer effect, for engineering electronic and mass transport properties of metal oxide thin films useful for a collection of relevant solid-state devices.

Atomic-Scale Determination of Cation Inversion in Spinel-Based Oxide Nanoparticles

The atomic structure of nanoparticles can be easily determined by transmission electron microscopy. However, obtaining atomic-resolution chemical information about the individual atomic columns is a rather challenging endeavor. Here, crystalline monodispersed spinel Fe₃O₄/Mn₃O₄ core-shell nanoparticles have been thoroughly characterized in a high-resolution scanning transmission electron microscope. Electron energy-loss spectroscopy (EELS) measurements performed with atomic resolution allow the direct mapping of the Mn²⁺/Mn³⁺ ions in the shell and the Fe²⁺/Fe³⁺ in the core structure. This enables a precise understanding of the core-shell interface and of the cation distribution in the crystalline lattice of the nanoparticles. Considering how the different oxidation states of transition metals are reflected in EELS, two methods of performing a local evaluation of the cation inversion in spinel lattices are introduced. Both methods allow the determination of the inversion parameter in the iron oxide core and manganese oxide shell, as well as detecting spatial variations in this parameter, with atomic resolution. X-ray absorption measurements on the whole sample confirm the presence of cation inversion. These results present a significant advance toward a better correlation of the structural and functional properties of nanostructured spinel oxides.

Different growth regimes in InP nanowire growth mediated by Ag nanoparticles

We report on the existence of two different regimes in one-step Ag-seeded InP nanowire growth. The vapor-liquid-solid-mechanism is present at larger In precursor flows and temperatures, ∼500 °C, yielding high aspect ratio and pure wurtzite InP nanowires with a semi-spherical metal particle at the thin apex. Periodic diameter oscillations can be achieved under extreme In supersaturations at this temperature range, showing the presence of a liquid catalyst. However, under lower temperatures and In precursor flows, large diameter InP nanowires with mixed wurtzite/zincblende segments are obtained, similarly to In-assisted growth. Chemical composition analysis suggest that In-rich droplet formation is catalyzed at the substrate surface via Ag nanoparticles; this process might be facilitated by the sulfur contamination detected in these nanoparticles. Furthermore, part of the original Ag nanoparticle remains solid and is embedded inside the actual catalyst, providing an in situ method to switch growth mechanisms upon changing In precursor flow. Nevertheless, our Ag-seeded InP nanowires exhibit overall optical emission spectra consistent with the observed structural properties and similar to Au-catalyzed InP nanowires. We thus show that Ag nanoparticles may be a suitable replacement for Au in InP nanowire growth.

A national level assessment of metal contamination in bats

Many populations of bat species across the globe are declining, with chemical contamination one of many potential stressors implicated in these demographic changes. Metals still contaminate a wide range of habitats, but the risks to bats remain poorly understood. This study is the first to present a national scale assessment of toxic metal (Cd, Pb) and essential trace metal (Cu, Zn) concentrations in bats. Metal concentrations in tissues (kidneys, liver, stomach -stomach content, bones and fur) were measured in 193 Pipistrellus sp. in England and Wales using ICP-MS, and compared to critical toxic concentrations for small mammals. The concentrations of metals determined in bat tissues were generally lower than those reported elsewhere. Strong positive associations were found between concentrations in tissues for a given metal (liver and kidneys for Cd, Cu and Pb; stomach and fur and fur and bones for Pb), suggesting recent as well as long term exposure to these contaminants. In addition, positive correlations between concentrations of different metals in the same tissues (Cd and Zn, Cu and Zn, Cd and Pb, Pb and Zn) suggest a co-exposure of metals to bats. Approximately 21% of the bats sampled contained residues of at least one metal at concentrations high enough to elicit toxic effects (associated with kidney damage), or to be above the upper level measured in other mammal species. Pb was found to pose the greatest risk (with 7-11% of the bats containing concentrations of toxicological concern), followed by Cu (4-9%), Zn (0.5-5.2%) and Cd (0%). Our data suggest that leaching of metals into our storage matrix, formaldehyde, may have occurred, especially for Cu. The overall findings suggest that metal contamination is an environmental stressor affecting bat populations, and that further research is needed into the direct links between metal contamination and bat population declines worldwide.

Fur: A non-invasive approach to monitor metal exposure in bats

This paper presents a novel assessment of the use of fur as a non-invasive proxy to biomonitor metal contamination in insectivorous bats. Concentrations of metals (cadmium, copper, lead and zinc) were measured using ICP-MS in tissues (kidneys, liver, stomach and stomach content, bones and fur) obtained from 193 Pipistrellus pipistrellus/pygmaeus bats. The bats were collected across a gradient of metal pollution in England and Wales. The utility of small samples of fur as an indicator of metal exposure from the environment was demonstrated with strong relationships obtained between the concentrations of non-essential metals in fur with concentrations in stomach content, kidneys, liver and bones. Stronger relationships were observed for non-essential metals than for essential metals. Fur analyses might therefore be a useful non-invasive proxy for understanding recent, as well as long term and chronic, metal exposure of live animals. The use of fur may provide valuable information on the level of endogenous metal exposure and contamination of bat populations and communities.

Neuroprotective role of hydralazine in rat spinal cord injury-attenuation of acrolein-mediated damage

Acrolein, an α,β-unsaturated aldehyde and a reactive product of lipid peroxidation, has been suggested as a key factor in neural post-traumatic secondary injury in spinal cord injury (SCI), mainly based on in vitro and ex vivo evidence. Here, we demonstrate an increase of acrolein up to 300%; the elevation lasted at least 2 weeks in a rat SCI model. More importantly, hydralazine, a known acrolein scavenger can provide neuroprotection when applied systemically. Besides effectively reducing acrolein, hydralazine treatment also resulted in significant amelioration of tissue damage, motor deficits, and neuropathic pain. This effect was further supported by demonstrating the ability of hydralazine to reach spinal cord tissue at a therapeutic level following intraperitoneal application. This suggests that hydralazine is an effective neuroprotective agent not only in vitro, but in a live animal model of SCI as well. Finally, the role of acrolein in SCI was further validated by the fact that acrolein injection into the spinal cord caused significant SCI-like tissue damage and motor deficits. Taken together, available evidence strongly suggests a critical causal role of acrolein in the pathogenesis of spinal cord trauma. Since acrolein has been linked to a variety of illness and conditions, we believe that acrolein-scavenging measures have the potential to be expanded significantly ensuring a broad impact on human health.

Acrolein involvement in sensory and behavioral hypersensitivity following spinal cord injury in the rat

Growing evidence suggests that oxidative stress, as associated with spinal cord injury (SCI), may play a critical role in both neuroinflammation and neuropathic pain conditions. The production of the endogenous aldehyde acrolein, following lipid peroxidation during the inflammatory response, may contribute to peripheral sensitization and hyperreflexia following SCI via the TRPA1-dependent mechanism. Here, we report that there are enhanced levels of acrolein and increased neuronal sensitivity to the aldehyde for at least 14 days after SCI. Concurrent with injury-induced increases in acrolein concentration is an increased expression of TRPA1 in the lumbar (L3-L6) sensory ganglia. As proof of the potential pronociceptive role for acrolein, intrathecal injections of acrolein revealed enhanced sensitivity to both tactile and thermal stimuli for up to 10 days, supporting the compound's pro-nociceptive functionality. Treatment of SCI animals with the acrolein scavenger hydralazine produced moderate improvement in tactile responses as well as robust changes in thermal sensitivity for up to 49 days. Taken together, these data suggest that acrolein directly modulates SCI-associated pain behavior, making it a novel therapeutic target for preclinical and clinical SCI as an analgesic. Following spinal cord injury (SCI), acrolein involvement in neuropathic pain is likely through direct activation and elevated levels of pro-nociceptive channel TRPA1. While acrolein elevation correlates with neuropathic pain, suppression of this aldehyde by hydralazine leads to an analgesic effect. Acrolein may serve as a novel therapeutic target for preclinical and clinical SCI to relieve both acute and chronic post-SCI neuropathic pain.

Determination of urine 3-HPMA, a stable acrolein metabolite in a rat model of spinal cord injury

Acrolein has been suggested to be involved in a variety of pathological conditions. The monitoring of acrolein is of significant importance in delineating the pathogenesis of various diseases. Aimed at overcoming the reactivity and volatility of acrolein, we describe a specific and stable metabolite of acrolein in urine, N-acetyl-S-3-hydroxypropylcysteine (3-HPMA), as a potential surrogate marker for acrolein quantification. Using the LC/MS/MS method, we demonstrated that 3-HPMA was significantly elevated in a dose-dependent manner when acrolein was injected into rats IP or directly into the spinal cord, but not when acrolein scavengers were co-incubated with acrolein solution. A nonlinear mathematic relationship is established between acrolein injected directly into the spinal cord and a correlated dose-dependent increase of 3-HPMA, suggesting the increase of 3-HPMA becomes less apparent as the level of injected acrolein increases. The elevation of 3-HPMA was further detected in the rat spinal cord injury, a pathological condition known to be associated with elevated endogenous acrolein. This finding was further validated by concomitant confirmation of increased acrolein-lysine adducts using established dot immunoblotting techniques. The noninvasive nature of measuring 3-HPMA concentrations in urine allows for long-term monitoring of acrolein in the same animal and ultimately in human clinical studies. Due to wide spread involvement of acrolein in human health, the benefits of this study have the potential to enhance human health significantly.

Nanocrystallinity and the ordering of nanoparticles in two-dimensional superlattices: controlled formation of either core/shell (Co/CoO) or hollow CoO nanocrystals

Here it is demonstrated that the diffusion process of oxygen in Co nanoparticles is controlled by their 2D ordering and crystallinity. The crystallinity of isolated Co nanoparticles deposited on a substrate does not play any role in the oxide formation. When they are self-assembled in 2D superlattices, the oxidation process is slowed and produces either core/shell (Co/CoO) nanoparticles or hollow CoO nanocrystals. This is attributed to the decrease in the oxygen diffusion rate when the nanoparticles are interdigitated. Initially, polycrystalline nanoparticles form core/shell (Co/CoO) structures, while for single-domain hexagonal close-packed Co nanocrystals, the outward diffusion of Co ions is favored over the inward diffusion of oxygen, producing hollow CoO single-domain nanocrystals.

Improved detection of myocardial involvement in acute inflammatory cardiomyopathies using T2 mapping

BACKGROUND

T2-weighted cardiac magnetic resonance imaging is useful in diagnosing acute inflammatory myocardial diseases, such as myocarditis and tako-tsubo cardiomyopathy (TTCM). We hypothesized that quantitative T2 mapping could better delineate myocardial involvement in these disorders versus T2-weighted imaging.

METHODS AND RESULTS

Thirty patients with suspected myocarditis or TTCM, referred for cardiac magnetic resonance imaging, who met established diagnostic criteria underwent myocardial T2 mapping. T2 values were averaged in involved and remote myocardial segments, both defined by a reviewer blinded to T2 data. In myocarditis, T2 was 65.2±3.2 ms in the involved myocardium versus 53.5±2.1 ms in the remote myocardium (P<0.001). In TTCM, T2 was 65.6±4.0 ms in the involved myocardium versus 53.6±2.7 ms in the remote segments (P<0.001). T2 values were similar across remote myocardial segments in patients and all myocardial segments in controls (P>0.05 for all). T2 maps provided diagnostic data even in patients with difficulty breath holding. A T2 cutoff of 59 ms identified areas of myocardial involvement, with sensitivity and specificity of 94% and 97%, respectively. T2 mapping revealed regions of abnormal T2 beyond those identified by wall motion abnormalities or late gadolinium-enhancement positivity. Conventional T2-weighted short tau inversion recovery images were uninterpretable in 7 patients because of artifact and unremarkable in 2 patients who had elevated T2 values. T2-prepared steady-state-free precession images showed areas of signal hyperintensity in only 17 of 30 patients.

CONCLUSIONS

Quantitative T2 mapping reliably identifies myocardial involvement in patients with myocarditis and TTCM. T2 mapping delineated a greater extent of myocardial disease in both conditions compared with that identified by wall motion abnormalities, T2-weighted short tau inversion recovery imaging, T2-prepared steady-state-free precession, or late gadolinium enhancement. Quantitative T2 mapping warrants consideration as a robust technique to identify myocardial injury in patients with acute myocarditis or TTCM.

Unusual surgical repair of the Taussig-Bing heart: evaluation of complex anatomy in the adult with congenital heart disease with cardiovascular magnetic resonance

Double outlet right ventricle is a heterogeneous congenital defect that encompasses a variety of anatomic aberrations and physiologic consequences. We describe the unusual cardiovascular magnetic resonance anatomic findings and sequelae of a 44-year-old man who underwent biventricular repair of double outlet right ventricle, subpulmonary type, which included tunneling of the ventricular septal defect to the pulmonary artery, right ventricular-to-pulmonary artery conduit and Damus-Kaye-Stansel procedure.

How can the nanocrystallinity of 7 nm spherical Co nanoparticles dispersed in solution be improved?

We report a solution-phase annealing of spherical Co nanocrystals synthesized in reverse micelles and coated with dodecanoic acid. The deposition of a drop of solution on a transmission electron microscope grid shows that a progressive increase in the temperature to 316 °C results in the progressive crystallographic transition from a polycrystalline and probably face-centered cubic Co phase to the single-crystalline hexagonal close-packed (hcp) Co phase. These nanocrystals are highly stable against oxidation and coalescence. We stress that, to our knowledge, this constitutes the first example in the literature of pure hcp-Co spherical single crystals dispersed in solution. These nanocrystals can be freely manipulated and, due to their low size dispersion, can self-organize on various substrates.

Blocking of indium incorporation by antimony in III-V-Sb nanostructures

The addition of antimony to III-V nanostructures is expected to give greater freedom in bandgap engineering for device applications. One of the main challenges to overcome is the effect of indium and antimony surface segregation. Using several very high resolution analysis techniques we clearly demonstrate blocking of indium incorporation by antimony. Furthermore, indium incorporation resumes when the antimony concentration drops below a critical level. This leads to major differences between nominal and actual structures.

Multi-dimensional and multi-signal approaches in scanning transmission electron microscopes

Developments in instrumentation are essential to open new fields of science. This clearly applies to electron microscopy, where recent progress in all hardware components and in digitally assisted data acquisition and processing has radically extended the domains of application. The demonstrated breakthroughs in electron optics, such as the successful design and practical realization and the use of correctors, filters and monochromators, and the permanent progress in detector efficiency have pushed forward the performance limits, in terms of spatial resolution in imaging, as well as for energy resolution in electron energy-loss spectroscopy (EELS) and for sensitivity to the identification of single atoms. As a consequence, the objects of the nanoworld, of natural or artificial origin, can now be explored at the ultimate atomic level. The improved energy resolution in EELS, which now encompasses the near-IR/visible/UV spectral domain, also broadens the range of available information, thus providing a powerful tool for the development of nanometre-level photonics. Furthermore, spherical aberration correctors offer an enlarged gap in the objective lens to accommodate nanolaboratory-type devices, while maintaining angström-level resolution for general characterization of the nano-object under study.

Immunity of coated self-ordered silver nanocrystals: a new intrinsic property due to the nanocrystal ordering

New materials made of two- and three-dimensional superlattices of nanoparticles exhibit unique collective properties arising from the ordering of the nanoparticles. Here, dodecanethiol-coated silver nanocrystals self-assembled in 2D were subjected to oxygen plasma using the reactive ion etching process. The careful investigation by transmission electronic microscopy (TEM) of the same areas before and after exposure allows one to distinguish two behaviors under plasma treatment, which are determined by the level of ordering of the 2D organizations. Higher ordered self-assemblies remain unchanged, while less ordered organizations coalesce into larger nanocrystals with spheroidal shapes that could be single crystals. Electron energy-loss spectroscopy (EELS) measurements show that there is no oxidation of the silver either on the large coalesced nanocrystals or on the stable self-assemblies. A new intrinsic property, immunity of highly self-ordered nanocrystals provided by the ordering, is reported, and a mechanism of the coalescence is proposed.

Extending the analysis of EELS spectrum-imaging data, from elemental to bond mapping in complex nanostructures

Multiple least squares fitting has been employed for long time in elemental electron energy-loss spectroscopy (EELS) analysis, in particular in biology, but with the hypothesis of a rather stable shape for the used core-loss signals. In the present case, we explore its use for identifying the variations in the edges' fine structures in complex boron nitride samples and in particular for mapping the bonding types of boron in such samples. Details about this improved procedure applied to data acquired in the spectrum-imaging mode are reported here.

2D self-organization of core/shell Co(hcp)/Co nanocrystals

In this paper we report the preparation of ordered hexagonal 2D arrays of core/shell Cohcp/CoO nanocrystals. A full structural investigation has been carried out using high-resolution transmission electron microscopy, electron diffraction, and electron energy-loss spectroscopy.

Orthopedic trauma!

Patients with broken bones or crush injuries are at risk for life-threatening complications--acute compartment syndrome, rhabdomyolysis, and fat embolism syndrome. Do you know how to recognize these complications quickly and respond?

Electrochemical and microstructural studies of tantalum and its oxide films for biomedical applications in endovascular surgery

The most popular coronary stents are made of 316L stainless steel and self-expandable Nitinol. Nevertheless, Ta has already been used to make stents for endovascular surgery and may constitute a good alternative to the other materials because of its higher corrosion resistance and radio-opacity property, which may facilitate the follow-up of stent catheterization. The characterization of Ta and its natural passive oxide films has been performed in a 0.15 M NaCl solution (simulated body fluid - SBF) using anodic polarizations, electrochemical impedance spectroscopy and photoelectrochemical techniques. Changes in microstructure have been observed by atomic force microscopy (AFM). Polarization curves show the existence of a current density increase between 1.40 and 1.80 V. Bode complex plots show that some perturbation of the film occurred in this potential interval which may be associated with a decrease in polarization resistance, Rp, indicating that the film may be less resistant to corrosive attack. Mott-Schottky capacity measurements show that the density of donors, Nd, varies with polarization. The optical band gap, E(g), which is equal to 4.1 eV did not show variations in our experiments. The localized formation on the electrode surface, in the above potential interval of a Ta compound (possibly an oxide-hydroxide) was observed by AFM, and this may explain the appearance of the current density peak and capacity behavior at those potentials.

The effect of neighborhood-based community organizing: results from the Seattle Minority Youth Health Project

OBJECTIVE

To evaluate the effect of a community mobilization and youth development strategy to prevent drug abuse, violence, and risky sexual activity.

DATA SOURCES/STUDY SETTING

Primary surveys of youth, parents, and key neighborhood leaders were carried out at baseline (1994) and at the end of the intervention period (1997). The study took place in four intervention and six control neighborhoods in Seattle.

STUDY DESIGN

The study was designed as a randomized controlled trial with neighborhood as the unit of randomization. The intervention consisted of a paid community organizer in each neighborhood who recruited a group of residents to serve as a community action board. Key variables included perceptions of neighborhood mobilization by youth, parents, and key neighborhood leaders.

DATA COLLECTION/EXTRACTION METHODS

Youth surveys were self-administered during school hours. Parent and neighborhood leader surveys were conducted over the phone by trained interviewers.

PRINCIPAL FINDINGS

Survey results showed that mobilization increased to the same degree in both intervention and control neighborhoods with no evidence of an overall intervention effect. There did appear to be a relative increase in mobilization in the neighborhood with the highest level of intervention activity.

CONCLUSION

This randomized study failed to demonstrate a measurable effect for a community mobilization intervention. It is uncertain whether the negative finding was because of a lack of strength of the interventions or problems detecting intervention effects using individual-level closed-end surveys.

Cost-effectiveness of combined outreach for the pneumococcal and influenza vaccines

BACKGROUND

We conducted a cost-effectiveness analysis as part of a randomized, controlled trial of a community-based outreach initiative to promote the pneumococcal and influenza vaccines for people aged 65 years or older.

METHODS

The analysis was based on primary data from the trial on the increase in vaccination rates and cost of the intervention, and published estimates of the effectiveness of the vaccines and cost of treatment. We performed partial stochastic analyses based on the confidence intervals (CIs) of the effectiveness of the intervention and of the vaccines.

RESULTS

The cost-effectiveness ratio of the combined-outreach initiative as implemented was $35 486 per quality-adjusted life-year (QALY), whereas it was $53 547 per QALY for the pneumococcal vaccine and $130 908 per QALY for the influenza vaccine. In partial stochastic analyses, the quasi-CI of the combined-outreach initiative ranged from $15 145 to $152 311 per QALY. The cost-effectiveness ratio of the intervention targeted to people who had never received the pneumococcal vaccine or who had not received the influenza vaccine in the previous year was $11 771 per QALY, with a quasi-CI of $3330 to $46 095 per QALY. With the use of the projected cost of replicating the intervention, the cost-effectiveness ratio was $26 512 per QALY for the initiative as implemented and $7843 per QALY for a targeted initiative.

CONCLUSIONS

The community-based outreach initiative to promote the pneumococcal and influenza vaccines was reasonably cost-effective. Further improvements in cost-effectiveness could be made by targeting the initiative or through lessons learned during the first year that would reduce the cost of the initiative in subsequent years.

Measuring community mobilization in the Seattle Minority Youth Health Project

This article assesses the validity and reliability of the approach used to measure community mobilization in the Seattle Minority Youth Health Project (MY Health), a neighborhood-based program to prevent drug use, violence, teen pregnancy, and sexually transmitted diseases (STDs). Two constructs were measured: neighborhood cooperation in solving problems, and sense of pride and identification with the neighborhood. The convergent validity of the measurement approach was assessed by comparing several independent measures of community mobilization generated from surveys of key neighborhood leaders, youth, and parents. For the neighborhood cooperation construct, correlations were uniformly positive across measures from different surveys and statistically significant about a quarter of the time. The correlations for the neighborhood pride construct were weaker and generally not statistically significant. Interrater reliability was low for all of the surveys, possibly reflecting varying ideas about what community mobilization meant among survey respondents.

Adaptations and resistance of zooplankton to stress: effects of genetic, environmental, and physiological factors

The ability of a species to adapt to stress factors such as exposure to toxicants depends to a large extent on the presence of individuals that are able to respond to the exposure in a successful way. Several strategies can be employed to cope with different stress factors. Investments on growth and reproduction, for instance, can be varied to meet the requirements of the environment. Large individuals generally have a high resistance against stress, but a large body size is often achieved at the cost of other characteristics. In the present study, the resistance of several clones of Daphnia to different stress factors, such as toxic cyanobacteria, a predator released chemical, and starvation, was investigated. The focus was on interactions among different factors and whether observed responses can be regarded as evolved adaptations for the different conditions.

Acute renal failure due to sulfinpyrazone

A case of sulfinpyrazone-associated acute renal failure is reported. Sulfinpyrazone can cause reversible acute renal failure from acute tubular necrosis in patients with volume depletion. Brown tubular casts on urine microscopy and a fractional excretion of sodium greater than 1 are helpful in the diagnosis. Uric acid nephropathy and allergic interstitial nephritis should be included in the differential diagnosis of sulfinpyrazone-associated acute renal failure. Acute reduction of renal blood flow due to inhibition of renal prostaglandin synthesis and kallikrein activity by the drug is a possible mechanism. Treatment of sulfinpyrazone-induced acute tubular necrosis consists of intravascular hydration, supportive care, and withholding sulfinpyrazone. The patients at risk for acute renal failure due to sulfinpyrazone are those who have intravascular volume depletion as sensed by the kidneys.