Generalization of Self-Assembly Toward Differently Shaped Colloidal Nanoparticles for Plasmonic Superlattices

Periodic superlattices of noble metal nanoparticles  have demonstrated superior plasmonic properties compared to randomly distributed plasmonic arrangements due to near-field coupling and constructive far-field interference. Here, a chemically driven, templated self-assembly process of colloidal gold nanoparticles is investigated and optimized, and the technology is extended toward a generalized assembly process for variously shaped particles, such as spheres, rods, and triangles. The process yields periodic superlattices of homogenous  nanoparticle clusters on a centimeter scale. Electromagnetically simulated absorption spectra and corresponding experimental extinction measurements demonstrate excellent agreement in the far-field for all particle types and different lattice periods. The electromagnetic simulations reveal the specific nano-cluster near-field behavior, predicting the experimental findings provided by surface-enhanced Raman scattering measurements. It turns out that periodic arrays of spherical nanoparticles produce higher surface-enhanced Raman scattering enhancement factors than particles with less symmetry as a result of very well-defined strong hotspots.

Photonic Materials Cloud: An Online Interactive Open Tool for Creating, Comparing, and Testing Photonic Materials

Recent advances in nanoscale fabrication and characterization further accelerated research on photonics and plasmonics, which has already attracted long-standing interest. Alongside morphological constraints, phenomena in both fields highly depend on the materials’ optical properties, dimensions, and surroundings. Building up the required knowledge and experience to design next-generation photonic devices can be a complex task for novice and experienced researchers who intend to evaluate the impact of subtle material and morphology variations while setting up experiments or getting a general overview. Here, we introduce the Photonic Materials Cloud (PMCloud), a web-based, interactive open tool for designing and analyzing photonic materials. PMCloud allows identification of the subtle differences between optical material models generated from a database, experimental data input, and inline-generated materials from various analytical models. Furthermore, it provides a fully interactive interface to evaluate their performance in important fundamental (numerical) optical experiments. We demonstrate PMCloud’s applicability to state-of-the-art research questions, namely the comparison of the novel plasmonic materials aluminium-doped zinc oxide and zirconium nitride and the design of an optical, dielectric thin-film Bragg reflector. PMCloud opens a rapid, freely accessible path towards prototyping optical materials and simple fundamental devices and may serve as an educational platform for photonic materials research.

Comparison of the prognostic value of stress and rest pulmonary transit time estimation using myocardial perfusion CMR

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation Clinical Research Training Fellowship

Background

Pulmonary transit time (PTT) is a quantitative biomarker of cardiopulmonary status. Rest PTT was previously shown to predict outcomes in specific disease models, but clinical adoption is hindered but challenges in data acquisition. Whether evaluation of PTT during stress encodes incremental prognostic information has not been previously investigated as scale.

Objectives

To compare the prognostic value of stress and rest PTT derived from a fully automated, in-line method of estimation using perfusion CMR, in a large patient cohort.

Methods

A retrospective two-center study of patients referred clinically for adenosine stress myocardial perfusion assessment using CMR. Analysis of right and left ventricular cavity arterial input function curves from first pass perfusion was performed automatically, allowing the in-line estimation of both rest and stress PTT. Association with major adverse cardiovascular events (MACE) was evaluated. MACE was defined as a composite outcome of myocardial infarction, stroke, heart failure admission and ventricular tachycardia or appropriate ICD treatment (including ICD shock and/or anti-tachycardia pacing).

Results

985 patients (67% male, median age 62 years (IQR 52,71)) were included, with median left ventricular ejection fraction (LVEF) of 62% (IQR 54-69). Median stress PTT was shorter than rest PTT 6.2 (IQR 5.1, 7.7) seconds versus 7.7 (IQR, 6.4, 9.2) seconds. Stress and rest PTT were highly correlated (r = 0.69; p < 0.001). Stress PTT also correlated with LVEF (r=-0.37), stress MBF (r=-0.31), LVEDVi (r = 0.24), LA area index (r = 0.32) (p < 0.001 for all). Over a median follow-up period of 28.6 (IQR, 22.6 35,7) months, MACE occurred in 61 (6.2%) patients. After adjusting for prognostic factors, both rest and stress PTT, independently predicted MACE, but not all-cause mortality. For every 1xSD (2.39s) increase in rest PTT the adjusted hazard ratio (HR) for MACE was 1.43 (95% CI 1.10-1.85, p = 0.007). The hazard ratio for one standard deviation (2.64s) increase in stress PTT was 1.34 (95% CI 1.048-1.723; p = 0.020) after adjusting for age, LVEF, hypertension, diabetes, sex and presence of LGE

Conclusions

In this 2-center study of 985 patients, we deploy a fully automated method of PTT estimation using perfusion mapping with CMR and show that both stress and rest PTT are independently associated with adverse cardiovascular outcomes. In this patient cohort, there is no clear incremental prognostic value of stress PTT, over its evaluation during rest.

Figure 1. Stress and Rest Pulmonary Transit Time estimation using myocardial perfusion CMR

Figure 2. Event-free survival curves for major adverse cardiovascular events (Heart failure hospitalization, myocardial infarction, stroke and ventricular tachycardia/ICD treatment) according to mean rest PTT (8.05seconds) and mean stress PTT (6.7seconds). Log-rank for both p < 0.05

A cost analysis of cardiac magnetic resonance imaging in the diagnostic pathway of a population with unexplained acute myocardial injury and normal coronary angiography

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): National Institute for Health Research (NIHR) Biomedical Research Centre at St Bartholomew"s Hospital London. Irish Cardiac Society

OnBehalf

European Association of Cardiovascular Imaging (EACVI) -Task Force for Cost Effectiveness.

Background

Acute presentations with myocardial injury that occur despite culprit-free coronary angiography were first reported over 70 years ago, with a prevalence between 5-9%.  1-3 There is increasing evidence that a more accurate diagnosis is available and that CMR is a key tool to determine the underlying pathology. This is reflected with the most recent international guidelines advocating for the use of CMR in the diagnostic pathways of this heterogeneous population.  However, to date there is no formal assessment of the financial implications of adopting these new guidelines.

Purpose

To determine the financial impact of implementing cardiac magnetic resonance imaging in the diagnostic pathway of a population with unexplained acute myocardial injury and normal coronary angiography in comparison to existing clinical practice.

Methods

We performed a focused cost-benefit analysis using a hypothetical population of 2,000 patients with unexplained acute myocardial injury and normal coronary angiography.  The population was split evenly into two groups of either standard, or CMR guided management, and extrapolated over a ten-year period. Standard management was defined as 66% of the population receiving dual antiplatelet therapy (ticagrelor and aspirin) for one year followed by aspirin for life, and the remaining 34% of the population receiving aspirin for life. CMR guided management determined antiplatelet therapy according to the imaging findings. This analysis focused on CMR’s ability to accurately identify those patients who may have had an MI and facilitate tailored treatment with evidence based dual antiplatelet therapy. Costs and rates were defined in Table 1. A one-way sensitivity analysis was also performed to determine the variables with largest impact on the costs. Each variable was varied by +/- 20% and the change in cost determined at year 10.

Results

Using CMR in the diagnostic pathway resulted in an increased cost of £72,656 in the first year. After year 7, CMR guided practice becomes cost neutral, resulting in cost saving of £24,054 over a ten-year period in a population of 1000 patients. Figure 1. Utilizing CMR in this population also resulted in 7 fewer myocardial infarctions and 14 fewer major bleeding events over a ten-year time horizon.

The three most sensitive variables were, in decreasing order, the cost of CMR, the cost of ticagrelor and the percentage of the population with MI requiring DAPT. A 20% change from baseline resulted in a 320%, 247% and 162% change in costs at 10 years, respectively.

Conclusion

Utilizing CMR in this population may be associated with reduced costs in the medium to long term. The initial increased cost of CMR is offset over time, by delivering a more personalised, higher quality level of care to patients.

InterCarb: A Community Effort to Improve Interlaboratory Standardization of the Carbonate Clumped Isotope Thermometer Using Carbonate Standards

Increased use and improved methodology of carbonate clumped isotope thermometry has greatly enhanced our ability to interrogate a suite of Earth-system processes. However, interlaboratory discrepancies in quantifying carbonate clumped isotope (Δ47) measurements persist, and their specific sources remain unclear. To address interlaboratory differences, we first provide consensus values from the clumped isotope community for four carbonate standards relative to heated and equilibrated gases with 1,819 individual analyses from 10 laboratories. Then we analyzed the four carbonate standards along with three additional standards, spanning a broad range of δ47 and Δ47 values, for a total of 5,329 analyses on 25 individual mass spectrometers from 22 different laboratories. Treating three of the materials as known standards and the other four as unknowns, we find that the use of carbonate reference materials is a robust method for standardization that yields interlaboratory discrepancies entirely consistent with intralaboratory analytical uncertainties. Carbonate reference materials, along with measurement and data processing practices described herein, provide the carbonate clumped isotope community with a robust approach to achieve interlaboratory agreement as we continue to use and improve this powerful geochemical tool. We propose that carbonate clumped isotope data normalized to the carbonate reference materials described in this publication should be reported as Δ47 (I-CDES) values for Intercarb-Carbon Dioxide Equilibrium Scale.

A prospective study evaluating the integration of a multifaceted evidence-based medicine curriculum into early years in an undergraduate medical school

BACKGROUND

The importance of ensuring medical students are equipped with the skills to be able to practice evidence-based medicine (EBM) has been increasingly recognized in recent years. However, there is limited information on an effective EBM curriculum for undergraduate medical schools. This study aims to test the feasibility of integrating a multifaceted EBM curriculum in the early years of an undergraduate medical school. This was subsequently evaluated using the validated Fresno test and students' self-reported knowledge and attitudes as they progressed through the curriculum.

METHODS

EBM was integrated horizontally and vertically into the curriculum into the first 2 years of undergraduate medical school. First year medical students were recruited to participate in the study. The 212-point Fresno test was administered along with a locally developed questionnaire at baseline before EBM teaching in year one and at the end of EBM teaching in year two.

RESULTS

Thirty-one students participated at baseline and 55 students participated at the end of second year EBM teaching. For the 18 students who completed the Fresno at both time points, the average score increased by 38.7 marks (p < 0.001) after EBM teaching. Students felt confident in formulating clinical questions and in critically appraising journal articles after EBM teaching. EBM was perceived to be important to their future practice as a doctor and for improving patient outcomes at both time points.

CONCLUSIONS

It has been feasible to integrate a multifaceted, EBM curriculum from the first year of an undergraduate medical program. Early evaluation of the curriculum using the Fresno test has shown a significant increase in students' EBM knowledge. The curriculum also demonstrated an increase in students' perceptions of the clinical relevance of EBM in their developing practice.

[Aggression and subjective risk in emergency medicine : A survey]

BACKGROUND

Healthcare personnel may be faced with different degrees of violence and aggression, particularly concerning preclinical care. However, systematic data with respect to the frequency and type of violence in emergency medicine in Germany has not been researched.

METHODS AND OBJECTIVES

At an anesthesiology congress, an anonymous survey was distributed about the different kinds and extent of violent acts that the participants had experienced during their work in emergency medicine. Moreover, the participants' subjective feelings toward professional and personal safety when handling emergency cases were explored.

RESULTS

Every fourth participant in the survey (25.2 %) had experienced occupational physical violence within the last 12 months. Verbal harassment or insults within the last twelve months were reported by 58.2 % of the participants. While 80 % of the participants feel "entirely" or "mostly" safe with regard to the professional aspect of their occupation, personal safety was considered "entirely" in only 9.3 % and "mostly" in 46.4 % of the cases. Nearly every third participant (31.8 %) feels only "partially" safe and every eighth participant feels "rather not" or "not at all" safe during emergency medicine missions. Men appreciate their expertise as well as their personal safety more so than women (p < 0.001).

CONCLUSION

Aggression and violence towards healthcare personnel in emergency medicine occur on a regular basis in the German healthcare system. Little research has been conducted in this area, so the issue has not yet been perceived as a relevant problem. Appropriate training for healthcare personnel in emergency medicine should be targeted at developing the skills needed when encountered with aggression and occupational violence.

The effect of increased classroom ventilation rate indicated by reduced CO2 concentration on the performance of schoolwork by children

The article reports on an experiment which investigated the effect of increased classroom ventilation rate on the performance of children aged 10-12 years. The experiment was executed at two different schools (two classrooms at each school) as a double-blind 2 × 2 crossover intervention where four different performance tests were used as surrogates for short-term concentration and logical thinking. Only complete pairs of test responses were included in the within-subject comparisons of performance, and data were not corrected for learning and fatigue effects. Analysis of the total sample suggested the number of correct answers was improved significantly in four of four performance test, addition (6.3%), number comparison (4.8%), grammatical reasoning (3.2%), and reading and comprehension (7.4%), when the outdoor air supply rate was increased from an average of 1.7 (1.4-2.0) to 6.6 l/s per person. The increased outdoor air supply rate did not have any significant effect on the number of errors in any of the performance tests. Results from questionnaires regarding pupil perception of the indoor environment, reported Sick Building Syndrome symptoms, and motivation suggested that the study classroom air was perceived more still and pupil were experiencing less pain in the eyes in the recirculation condition compared to the fresh air condition.

The role of the P2X7 receptor on bone loss in a mouse model of inflammation-mediated osteoporosis

In inflammatory autoimmune diseases, bone loss is frequent. In most cases, secondary osteoporosis is caused by treatment with systemic glucocorticoid. However, the pathogenesis behind the bone loss is presumed multifactorial. We aimed to elucidate the role of the P2X7 receptor on bone mineral density (BMD), microarchitecture, and bone strength in a standardized mouse model of inflammation-mediated osteoporosis (IMO). In total 146 mice completed our protocol, 70 wild type (WT) mice and 76 P2X7 -/- (knockout, KO). BMD at the femur and spine decreased significantly from baseline to day 20 in the WT IMO mice (p < 0.01). In the WT vehicle, KO vehicle and KO IMO, no significant BMD changes were found. Bone strength showed a lower mid-shaft max strength (p = 0.038) and also a non-significant trend towards lower strength at the femoral neck of the WT IMO group. Trabecular bone volume fraction (BV/TV) and connectivity density (CD) after 20 days were significantly decreased in the WT IMO group (p = 0.001). In contrast, the WT vehicle and KO vehicle, BV/TV and CD did no change at 20 days. Cortical bone revealed no significant microarchitectural changes after 20 days in the WT IMO group, whereas the total cortical area increased significantly in WT vehicle and KO IMO after 20 days (5.2% and 8.8%, respectively). In conclusion, the P2X7 receptor KO mice did not respond to inflammation with loss of BMD whereas the WT mice had a significant loss of BMD, bone strength and trabecular microarchitecture, demonstrating a role for the P2X7 receptor in inflammatory bone loss.

[Immunity against measles among healthcare personnel at the University Hospital Frankfurt, 2003-2013]

BACKGROUND

Despite aiming for the elimination of measles by 2015, the current epidemiological situation in Germany shows that there is still insufficient vaccination coverage among the population. During the present pre-elimination period, nosocomial measles are gaining in importance.

AIM

The purpose of our study was to determine the immune status of measles among healthcare personnel and medical students at the University Hospital Frankfurt. Moreover, the knowledge of study participants regarding the WHO's goal of the elimination of measles and the general attitude towards vaccination recommendations were investigated.

METHODS

A retrospective study of measles seroprevalence was conducted among healthcare personnel and students at the University Hospital Frankfurt with an observation period of 11 years. In spring 2014, medical students were asked to complete an anonymous questionnaire regarding vaccination status, knowledge of measles and acceptance of measles vaccination recommendations.

RESULTS

In total, 9,933 serologies were evaluated and 85.7% of the participants had sufficient immunity against measles. Significant changes in immunity to measles over time were not observed. However, a significant difference in the immunity rate of participants born before 1970 and those born after1970 was found. Participants born before 1970 significantly more often showed sufficient immunity against measles compared to those born later (96.4 vs. 83.3 %, p < 0.0001). Almost 20 % of the medical students were not aware of their measles vaccination status and merely 70.7 % indicated that they had received two measles vaccinations. Furthermore, only 45.4 % of the medical students were familiar with the WHO's goal of eliminating measles by 2015; however 95 % could be classified as vaccination-supporters on the basis of the questionnaire.

CONCLUSIONS

Overall, the immunity rate of measles determined by serology within the study population did not reach the WHO goal of ≥ 95 %, and this gap was even greater in group of medical students. Despite the medical students' positive attitude towards vaccination guidelines, the awareness in this field awaits improvement.

2015 Update on Acute Adverse Reactions to Gadolinium based Contrast Agents in Cardiovascular MR. Large Multi-National and Multi-Ethnical Population Experience With 37788 Patients From the EuroCMR Registry

OBJECTIVES

Specifically we aim to demonstrate that the results of our earlier safety data hold true in this much larger multi-national and multi-ethnical population.

BACKGROUND

We sought to re-evaluate the frequency, manifestations, and severity of acute adverse reactions associated with administration of several gadolinium- based contrast agents during routine CMR on a European level.

METHODS

Multi-centre, multi-national, and multi-ethnical registry with consecutive enrolment of patients in 57 European centres.

RESULTS

During the current observation 37,788 doses of Gadolinium based contrast agent were administered to 37,788 patients. The mean dose was 24.7 ml (range 5-80 ml), which is equivalent to 0.123 mmol/kg (range 0.01 - 0.3 mmol/kg). Forty-five acute adverse reactions due to contrast administration occurred (0.12%). Most reactions were classified as mild (43 of 45) according to the American College of Radiology definition. The most frequent complaints following contrast administration were rashes and hives (15 of 45), followed by nausea (10 of 45) and flushes (10 of 45). The event rate ranged from 0.05% (linear non-ionic agent gadodiamide) to 0.42% (linear ionic agent gadobenate dimeglumine). Interestingly, we also found different event rates between the three main indications for CMR ranging from 0.05% (risk stratification in suspected CAD) to 0.22% (viability in known CAD).

CONCLUSIONS

The current data indicate that the results of the earlier safety data hold true in this much larger multi-national and multi-ethnical population. Thus, the "off-label" use of Gadolinium based contrast in cardiovascular MR should be regarded as safe concerning the frequency, manifestation and severity of acute events.

[Vaccine Preventable Diseases: Knowledge, Attitudes and Vaccination Status of Medical Students]

Study Objective: Health-care workers (HCW) have an increased risk of acquiring infectious diseases and constitute a risk of transmission to their patients. Medical students working as HCW should therefore have the same immunity against vaccine preventable diseases as HCW. The aim of the study was to assess medical students' knowledge and attitudes towards occupationally indicated vaccinations as well as their vaccination status. Methods: Questionnaires were anonymously answered by medical students of the fourth preclinical semester at the Goethe-University Frankfurt. Results and Conclusion: Despite a high acceptance among medical students concerning vaccinations in general, the knowledge and vaccination status of the students should be improved. For instance, only 46.4% of the medical students knew that there is a general recommendation for HCW to receive the influenza vaccination and only 76.8% of the students stated to have received 2 measles vaccinations. Overall, 2/3 of the students were "very much in favour of vaccinations" or "completely in favour of vaccinations" and estimated the probability for unvaccinated HCW to acquire an occupationally associated infectious disease to be "quite high" or "very high". Having observed a positive attitude among medical students towards vaccinations, it should be possible to reach high vaccination coverage amongst students by offering them occupationally indicated vaccinations. Further knowledge concerning vaccine preventable diseases and the occupation-related increased risk for infectious diseases should be offered, as well.

When ignorance is bliss: weight perception, body mass index and quality of life in adolescents

Background/Objectives:

Body weight is negatively associated with adolescent Health-Related Quality of Life (HRQoL). Despite this well-established relationship, some adolescents with obesity do not display the expected HRQoL decreases. This study hypothesised weight perception as a moderator of the association between weight status and adolescent HRQoL.

Subjects/Methods:

Subjects were secondary school students from an obesity prevention project in the Barwon South-West region of Victoria, Australia, entitled It's Your Move (N=3040). Measures included standardised body mass index (BMI-z; World Health Organization growth standards), weight perception and HRQoL, measured by the Paediatric Quality of Life Inventory. Linear regression and average marginal effect analyses were conducted on cross-sectional baseline data to determine the significance of any interaction between weight perception and measured weight status in shaping adolescent HRQoL.

Results:

The BMI-z/perceived weight status interaction was significantly associated with adolescent HRQoL outcomes. Adolescents with BMI z-scores in the overweight/obesity range who perceived themselves as overweight had lower HRQoL than those who perceived themselves as ‘about right.' Conversely, adolescents with BMI scores in the lower end of the normal range or in the thinness range who perceived themselves as underweight had lower HRQoL than those with ‘about right' perceptions.

Conclusions:

This was the first study to report third-variable impacts of a body-perception variable on the relationship between adolescent weight status and HRQoL. Adolescents' weight perceptions significantly moderated the relationship between overweight/obesity and reduced HRQoL. Adolescents who were outside the normal weight range and misperceived their objectively measured weight status enjoyed a higher HRQoL than adolescents whose weight perception was concordant with their actual weight status. These findings suggest that practitioners may need to exercise caution when educating adolescents about their weight status, as such ‘reality checks' may negatively impact on adolescent HRQoL. It is suggested that more research be conducted to examine this potential effect.

[Limitations of surgery for rectal cancer]

This article presents and summarizes different treatment options for rectal cancer. The aim of this article is an historical review of treating primary and recurrent rectal cancer, highlighting the development and advancement in surgical and multimodal therapy. Limitations, specifically regarding recurrent rectal cancer are discussed and reviewed. A R0 resection can almost always be achieved in primary rectal cancer. In recurrent rectal cancer a R0 resection with extended surgical resection can be achieved in up to 70 % of the cases. In addition, surgical therapy plays a crucial role in the case of metastatic disease but should be incorporated into a multimodal network. The analysis of tumor genetics and predictive parameters will lead to the emergence of new treatment concepts shifting the limits of the current gold standard. Oncological long-term survival and improving the quality of life are the main focal points.

Relationship between overweight and health-related quality of life in secondary school children in Fiji: results from a cross-sectional population-based study

OBJECTIVE

To investigate the relationship between excess weight (overweight and obesity) and health-related quality of life (HRQoL) in a sample of secondary school children in Fiji, by gender, age and ethnicity.

METHODS

The study comprised 8947 children from forms 3-6 (age 12-18 years) in 18 secondary schools on Viti Levu, the main island of Fiji. Body mass index (BMI) was calculated from measured height and weight, and weight status was classified according to the International Obesity Task Force recommendations. HRQoL was measured by the self-report version of the Pediatric Quality of Life Inventory 4.0.

RESULTS

HRQoL was similar in children with obesity and normal weight. Generally, this was replicated when analyzed separately by gender and ethnicity, but age stratification revealed disparities. In 12-14-year-old children, obesity was associated with better HRQoL, owing to better social and school functioning and well-being, and in 15-18-year olds with poorer HRQoL, owing to worse physical, emotional and social functioning and well-being (Cohen's d 0.2-0.3). Children with a BMI in the overweight range also reported a slightly lower HRQoL than children with a BMI in the normal weight range, but although statistically significant, the size of this difference was trivial (Cohen's d <0.2).

DISCUSSION

The results suggest that, overall there is no meaningful negative association between excess weight and HRQoL in secondary school children in Fiji. This is in contradiction to the negative relationship between excess weight and HRQoL shown in studies from other countries and cultures. The assumption that a large body size is associated with a lower quality of life cannot be held universally. Although a generally low HRQoL among children in Fiji may be masking or overriding the potential effect of excess weight on HRQoL, socio-economic and/or socio-cultural factors, may help to explain these relationships.

Cooperation between scientists, NGOs and industry in support of sustainable fisheries: the South African hake Merluccius spp. trawl fishery experience

This paper examines the increasingly close interaction between natural and social scientists, non-governmental organizations (NGO) and industry, in pursuit of responsible ecosystem-based management of fisheries. South Africa has committed to implementing an ecosystem approach to fisheries management. Management advice stems from multi-stakeholder representation on government-led scientific and management working groups. In the hake Merluccius capensis and Merluccius paradoxus fishery, the primary management measure is an annual total allowable catch (TAC), the level of which is calculated using a management procedure (MP) that is revised approximately every 4 years. Revision of the MP is a consultative process involving most stakeholders, and is based on simulation modelling of projected probable scenarios of resource and fishery dynamics under various management options. NGOs, such as the Worldwide Fund for Nature in South Africa (WWF-SA), have played an important role in influencing consumers, the fishing industry and government to develop responsible fishing practices that minimize damage to marine ecosystems. Cooperation between industry, government and scientists has helped to improve sustainability and facilitated the meeting of market-based incentives for more responsible fisheries. Research includes ecosystem modelling, spatial analysis and ecosystem risk assessment with increasing research focus on social and economic aspects of the fishery. A four-year cooperative experiment to quantify the effect of trawling on benthic community structure is being planned. The food requirements of top predators still need to be included in the TAC-setting formulae and more social and economic research is needed. This paper also demonstrates how NGO initiatives such as Marine Stewardship Council certification and the Southern African Sustainable Seafood Initiative, a traffic light system of classifying seafood for consumers, have contributed to responsible fishing practices, increased ecosystem research and public awareness. This fishery appears to have a good future, provided that the monitoring, control and surveillance systems continue to function, TACs remain within ecologically sustainable limits and the effective collaboration between government, industry, scientists and NGOs continues to drive positive change.

Ultrathin reduced graphene oxide films as transparent top-contacts for light switchable solid-state molecular junctions

A new type of solid-state molecular junction is introduced, which employs reduced graphene oxide as a transparent top contact that permits a self-assembled molecular monolayer to be photoswitched in situ, while simultaneously enabling charge-transport measurements across the molecules. The electrical switching behavior of a less-studied molecular switch, dihydroazulene/vinylheptafulvene, is described, which is used as a test case.

A mathematical model of the mechanical link between shortening of the cardiomyocytes and systolic deformation of the left ventricular myocardium

BACKGROUND

Left ventricular myocytes are arranged in a complex three-dimensional mesh. Since all myocytes contract approximately to the same degree, mechanisms must exist to enable force transfer from each of these onto the framework as a whole, despite the transmural differences in deformation strain. This process has hitherto not been clarified in detail.

OBJECTIVE

To present a geometrical model that establishes a mechanical link between the three-dimensional architecture and the function of the left ventricular myocardium.

METHODS

The left ventricular equator was modeled as a cylindrical tube of deformable but incompressible material, composed of virtual cardiomyocytes with known diastolic helical and transmural angles. By imposing reference circumferential, longitudinal, and torsional strains onto the model, we created a three-dimensional deformation field to calculate passive shortening of the myocyte surrogates. We tested two diastolic architectures: 1) a simple model with longitudinal myocyte surrogates in the endo- and epicardium, and circular ones in the midwall, and 2) a more accurate architecture, with progressive helical angle distribution varying from -60° in the epicardium to 60° in the endocardium, with or without torsion and transmural cardiomyocyte angulation.

RESULTS

The simple model caused great transmural unevenness in cardiomyocyte shortening; longitudinal surrogates shortened by 15% at all depths equal to the imposed longitudinal strain, whereas circular surrogates exhibited a maximum shortening of 23.0%. The accurate model exhibited a smooth transmural distribution of cardiomyocyte shortening, with a mean (range) of 17.0 (13.2-20.8)%. Torsion caused a shortening of 17.0 (15.2-18.9)% and transmural angulation caused a shortening of 15.2 (12.4-18.2)%. Combining the effects of transmural angulation and torsion caused a change of 15.2 (13.2-16.5)%.

CONCLUSION

A continuous transmural distribution of the helical angle is obligatory for smooth shortening of the cardiomyocytes, but a combination of torsional and transmural angulation changes is necessary to execute systolic mural thickening whilst keeping shortening of the cardiomyocytes within its physiological range.

Linking geology, fluid chemistry, and microbial activity of basalt- and ultramafic-hosted deep-sea hydrothermal vent environments

Hydrothermal fluids passing through basaltic rocks along mid-ocean ridges are known to be enriched in sulfide, while those circulating through ultramafic mantle rocks are typically elevated in hydrogen. Therefore, it has been estimated that the maximum energy in basalt-hosted systems is available through sulfide oxidation and in ultramafic-hosted systems through hydrogen oxidation. Furthermore, thermodynamic models suggest that the greatest biomass potential arises from sulfide oxidation in basalt-hosted and from hydrogen oxidation in ultramafic-hosted systems. We tested these predictions by measuring biological sulfide and hydrogen removal and subsequent autotrophic CO2 fixation in chemically distinct hydrothermal fluids from basalt-hosted and ultramafic-hosted vents. We found a large potential of microbial hydrogen oxidation in naturally hydrogen-rich (ultramafic-hosted) but also in naturally hydrogen-poor (basalt-hosted) hydrothermal fluids. Moreover, hydrogen oxidation-based primary production proved to be highly attractive under our incubation conditions regardless whether hydrothermal fluids from ultramafic-hosted or basalt-hosted sites were used. Site-specific hydrogen and sulfide availability alone did not appear to determine whether hydrogen or sulfide oxidation provides the energy for primary production by the free-living microbes in the tested hydrothermal fluids. This suggests that more complex features (e.g., a combination of oxygen, temperature, biological interactions) may play a role for determining which energy source is preferably used in chemically distinct hydrothermal vent biotopes.

Association of P2X7 receptor polymorphisms with bone mineral density and osteoporosis risk in a cohort of Dutch fracture patients

The P2X7 receptor is thought to be involved in bone physiology in a pro-osteogenic manner. Therefore, we examined associations between genetic variations in the P2X7 receptor gene and bone mineral density (BMD). We found an association between four non-synonymous polymorphism of the human P2X7 receptor and the risk of osteoporosis.

INTRODUCTION

The purpose of this study was to determine whether genetic variation in the P2X7 receptor gene (P2RX7) is associated with decreased BMD and risk of osteoporosis in fracture patients.

METHODS

Six hundred ninety women and 231 men aged≥50 years were genotyped for 15 non-synonymous P2RX7 SNPs. BMD was measured at the total hip, lumbar spine and femoral neck.

RESULTS

Four non-synonymous SNPs were associated with BMD. The Ala348Thr gain-of-function polymorphism was associated with increased BMD values at the lumbar spine (p=0.012). Decreased hip BMD values were associated with two loss-of-function SNPs in the P2RX7, i.e., in subjects homozygous for the Glu496Ala polymorphism as well as in subjects carrying at least one variant allele of the Gly150Arg polymorphism (p=0.018 and p=0.011; respectively). In men, we showed that subjects either heterozygous or homozygous for the Gln460Arg gain-of-function polymorphism in the P2RX7 had a significantly 40% decrease in risk of a lower T-score value (OR=0.58 [95%CI, 0.33-1.00]).

CONCLUSION

Thus, genetic aberrations of P2X7R function are associated with lower BMD and increased osteoporosis risk. Therefore, detection of non-synonymous SNPs within the P2RX7 might be useful for osteoporosis risk estimation at an early stage, potentially enabling better osteoporosis prevention and treatment.