Methane in aquifers and alluvium overlying a coal seam gas region: Gas concentrations and isotopic differentiation

The detection and attribution of methane in aquifers overlying oil and gas reservoirs has recently gained increasing attention internationally. The Surat Basin, in the Great Artesian Basin (GAB), Australia, hosts a coal seam gas (CSG) reservoir, with feedlots, town water supply, mines and agriculture that extract groundwater from aquifers that underly and overly the gas reservoir. This study aimed to use a multi-isotopic approach to differentiate biogenic methane generated in situ in GAB aquifers and the Condamine Alluvium, from the biogenic CSG produced from the underlying Walloon Coal Measures reservoir, to understand if gas had migrated or not. Dissolved methane (0.001 to 160 mg/l) and total methane concentrations (up to 91,818 ppmv) were measured using closed sampling methods and were higher than from open direct fill sampling (<0.001 to 25.4 mg/l), especially in gassy bores that contain dissolved methane above 10 to 13 mg/l. The CSG production waters and a gassy overlying aquifer bore had the most depleted water isotopes, and also the most enriched δ¹³C-DIC indicating strong methanogenesis. The majority of aquifers have isotopic signatures (δ¹³C-DIC, CH₄ and CO₂) indicating in situ methane production by primary CO₂ reduction or fermentation, distinct from secondary microbial CO₂ reduction in the CSG reservoir. Fractionation factors support methane production mainly via CO₂ reduction, with fermentation in a subset of aquifer samples. The gas wetness parameters (636 to 20,000) are consistent with mainly microbial gases, with low dissolved ethane (max 0.04 mg/l). The majority of aquifer and alluvium samples in this study are consistent with in situ methane production, not migration, however in several gassy bores the methane source could not be clearly identified. This study is broadly applicable to understanding methane sources in aquifers overlying CSG reservoirs.

Projecting seismicity induced by complex alterations of underground stresses with applications to geothermal systems

Seismicity associated with subsurface operations is a major societal concern. It is therefore critical to improve predictions of the induced seismic hazard. Current statistical approaches account for the physics of pore pressure increase only. Here, we present a novel mathematical model that generalises adopted statistics for use in arbitrary injection/production protocols and applies to arbitrary physical processes. In our model, seismicity is driven by a normalised integral over the spatial reservoir volume of induced variations in frictional Coulomb stress, which-combined with the seismogenic index-provides a dimensionless proxy of the induced seismic hazard. Our model incorporates the classical pressure diffusion based and poroelastic seismogenic index models as special cases. Applying our approach to modeling geothermal systems, we find that seismicity rates are sensitive to imposed fluid-pressure rates, temperature variations, and tectonic conditions. We further demonstrate that a controlled injection protocol can decrease the induced seismic risk and that thermo-poroelastic stress transfer results in a larger spatial seismic footprint and in higher-magnitude events than does direct pore pressure impact for the same amount of injected volume and hydraulic energy. Our results, validated against field observations, showcase the relevance of the novel approach to forecast seismic hazards induced by subsurface activities.

Completion rate and impact on physician-patient relationship of video consultations in medical oncology: a randomised controlled open-label trial

Background

Mobile phone video call applications generally did not undergo testing in randomised controlled clinical trials prior to their implementation in patient care regarding the rate of successful patient visits and impact on the physician–patient relationship.

Methods

The National Center for Tumour Diseases (NCT) MOBILE trial was a monocentric open-label randomised controlled clinical trial of patients with solid tumours undergoing systemic cancer therapy with need of a follow-up visit with their consulting physician at outpatient clinics. 66 patients were 1:1 randomised to receive either a standard in-person follow-up visit at outpatient clinics or a video call via a mobile phone application. The primary outcome was feasibility defined as the proportion of patients successfully completing the first follow-up visit. Secondary outcomes included success rate of further video calls, time spent by patient and physician, patient satisfaction and quality of physician–patient relationship.

Findings

Success rate of the first follow-up visit in the intention-to-treat cohort was 87.9% (29 of 33) for in-person visits and 78.8% (26 of 33) for video calls (relative risk: RR 0.90, 95% CI 0.70 to 1.13, p=0.51). The most common reasons for failure were software incompatibility in the video call and no-show in the in-person visit arm. The success rate for further video visits was 91.7% (11 of 12). Standardised patient questionnaires showed significantly decreased total time spent and less direct costs for patients (Δmean −170.8 min, 95% CI −246 min to −95.5 min), p<0.0001; Δmean −€14.37, 95% CI −€23.9 to −€4.8, p<0.005) and comparable time spent for physicians in the video call arm (Δmean 0.5 min, 95% CI −5.4 min to 6.4 min, p=0.86). Physician–patient relationship quality mean scores assessed by a validated standardised questionnaire were higher in the video call arm (1.13-fold, p=0.02).

Interpretation

Follow-up visits with the tested mobile phone video call application were feasible but software compatibility should be critically evaluated.

Trial registration number

DRKS00015788.

Caregivers' role in using a personal electronic health record: a qualitative study of cancer patients and caregivers in Germany

Background

Particularly in the context of severe diseases like cancer, many patients wish to include caregivers in the planning of treatment and care. Many caregivers like to be involved but feel insufficiently enabled. This study aimed at providing insight into patients’ and caregivers’ perspectives on caregivers’ roles in managing the patient portal of an electronic personal health record (PHR).

Methods

A descriptive qualitative study was conducted comprising two study phases: (1) Usability tests and interviews with patients with cancer and caregivers (2) additional patient interviews after a 3-month-pilot-testing of the PHR. For both study parts, a convenience sample was selected, focusing on current state of health and therapy process and basic willingness to participate and ending up with a mixed sample as well as saturation of data. All interviews were audio-recorded, pseudonymized, transcribed verbatim and qualitatively analyzed.

Results

Two main categories emerged from qualitative data: ‘Caregivers’ role’ and ‘Graduation of access rights’ – consisting of four subcategories each. The interviewed patients (n = 22) and caregivers (n = 9) felt that the involvement of caregivers is central to foster the acceptance of a PHR for cancer patients. However, their role varied from providing technical support to representing patients, e.g. if the patient’s state of health made this necessary. Heterogeneous opinions emerged regarding the question whether caregivers should receive full or graduated access on a patient’s PHR.

Conclusions

In order to support the patient and to participate in the care process, caregivers need up-to-date information on the patient’s health and treatment. Nevertheless, some patients do not want to share all medical data with caregivers, which might strain the patient-caregiver relationship. This needs to be considered in development and implementation of personal health records. Generally, in the debate on patient portals of a personal health record, paying attention to the role of caregivers is essential. By appreciating the important relationship between patients and caregivers right from the beginning, implementation, of a PHR would be enhanced.

Trial registration

ISRCTN85224823. Date of registration: 23/12/2015 (retrospectively registered).

Explicit Modeling of Radon-222 in HydroGeoSphere During Steady State and Dynamic Transient Storage

Transient storage zones (TSZs) are located at the interface of rivers and their abutting aquifers and play an important role in hydrological and biogeochemical functioning of rivers. The natural radioactive tracer ²²² Rn is a particularly well-suited tracer for studying TSZ water exchange and age. Although ²²² Rn measurement techniques have developed rapidly, there has been less progress in modeling ²²² Rn activities. Here, we combine field measurements with the numerical model HydroGeoSphere (HGS) to simulate ²²² Rn emanation, decay and transport during steady state (riffle-pool sequence) and transient (bank storage) conditions. Comparing the HGS mean water ages with the conventional ²²² Rn apparent ages during steady state showed a systemic underestimation of apparent age with increasing dispersion and especially where large concentration gradients exist within the subsurface. A large underestimation of apparent water age was also observed at the advective front during bank storage where regional high ²²² Rn groundwater mixes with newly infiltrated surface water. The explicit modeling of radiogenic tracers such as ²²² Rn offers a physical interpretation of this data as well as a useful way to test simplified apparent age models.

Utilizing a Prototype Patient-Controlled Electronic Health Record in Germany: Qualitative Analysis of User-Reported Perceptions and Perspectives

Background

Personal electronic health records (PHR) are considered instrumental in improving health care quality and efficiency, enhancing communication between all parties involved and strengthening the patient’s role. Technical architectures, data privacy, and applicability issues have been discussed for many years. Nevertheless, nationwide implementation of a PHR is still pending in Germany despite legal regulations provided by the eHealth Act passed in 2015. Within the information technology for patient-oriented care project funded by the Federal Ministry of Education and Research (2012-2017), a Web-based personal electronic health record prototype (PEPA) was developed enabling patient-controlled information exchange across different care settings. Gastrointestinal cancer patients and general practitioners utilized PEPA during a 3-month trial period. Both patients and physicians authorized by them could view PEPA content online and upload or download files.

Objective

This paper aims to outline findings of the posttrial qualitative study carried out to evaluate user-reported experiences, perceptions, and perspectives, focusing on their interpretation of PEPA beyond technical usability and views on a future nationwide implementation.

Methods

Data were collected through semistructured guide-based interviews with 11 patients and 3 physicians (N=14). Participants were asked to share experiences, views of perceived implications, and perspectives towards nationwide implementation. Further data were generated through free-text fields in a subsequent study-specific patient questionnaire and researcher’s notes. Data were pseudonymized, audiotaped, and transcribed verbatim. Content analysis was performed through the Framework Analysis approach. All qualitative data were systemized by using MAXQDA Analytics PRO 12 (Rel.12.3.1). Additionally, participant characteristics were analyzed descriptively using IBM SPSS Statistics Version 24.

Results

Users interpreted PEPA as a central medium containing digital chronological health-related documentation that simplifies information sharing across care settings. While patients consider the implementation of PEPA in Germany in the near future, physicians are more hesitant. Both groups believe in PEPA’s concept, but share awareness of concerns about data privacy and older or impaired people’s abilities to manage online records. Patients perceive benefits for involvement in treatment processes and continuity of care but worry about financing and the implementation of functionally reduced versions. Physicians consider integration into primary systems critical for interoperability but anticipate technical challenges, as well as resistance from older patients and colleagues. They omit clear positioning regarding PEPA’s potential incremental value for health care organizations or the provider-patient relationship.

Conclusions

Digitalization in German health care will continue to bring change, both organizational and in the physician-patient relationship. Patients endorse and expect a nationwide PEPA implementation, anticipating various benefits. Decision makers and providers need to contribute to closing modernization gaps by committing to new concepts and by invigorating transformed roles.

Neglected nano-effects of nanoparticles in the interpretation of their toxicity

Considering the traditional mass, concentration, or surface area of nanoparticles can affect the conclusions drawn from cell viability tests about the toxicity of nanoparticles.

ATP and NADPH coated iron oxide nanoparticles for targeting of highly metabolic tumor cells

The metabolic activity of tumor cells is known to be higher as compared to that of normal cells, which has been previously exploited to deliver nanomedicines to highly metabolic tumor cells. Unfortunately, current strategies, which are mostly based on complex energy sources, such as sugars, showed insufficient accumulation at the target sites. We here report the coating of IONPs with two essential units of cellular metabolism: adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH). ATP and NADPH were directly bound to the IONPs' surface using a simple aqueous method. Both molecules were used as coatings, i.e. as stabilizing agents, but also simultaneously as targeting molecules to deliver IONPs to highly metabolic tumor cells. Indeed, we found that the uptake of ATP-IONPs and NADPH-IONPs is correlated with the metabolic activity of tumor cells, especially regarding their cellular ATP levels and NADPH consumption. We also measured one of the highest MRI r₂ relaxivities for both ATP-IONPs and NADPH-IONPs. With the direct coating of IONPs with ATP and NADPH, we therefore provide an optimal platform to stabilize IONPs and at the same time promising properties for the targeting and detection of highly metabolic tumor cells.

Characterization of liposome-containing SPIONs conjugated with anti-CD20 developed as a novel theranostic agent for central nervous system lymphoma

Despite advances in neuroscience cancer research during the past decades, the survival of cancer patients has only marginally improved and the cure remains unlikely. The blood-brain barrier (BBB) is a major obstacle protecting the entry of therapeutic agents to central nervous system, especially for primary central nervous system lymphoma (PCNSL). Thus, the use of small nanoparticle as a drug carrier may be new strategies to overcome this problem. In this study, we fabricated liposome consisting of superparamagnetic iron oxide nanoparticles (SPIONs) functionalized with anti-CD20 (Rituximab; RTX). The designed nanoparticles have a theranostic property which is not only to improve drug delivery, but also to offer diagnostic and monitoring capabilities. TEM images revealed the spherical shape of liposome with the approximately average diameters about 140-190nm with slightly negatively charge surfaces. Superparamagnetic property of SPIONs-loaded liposomes was confirmed by VSM. Liposome colloidal could be prolonged at 4°C and 25°C storages. RTX conjugated liposome induced cell internalization and apoptosis effect in B-lymphoma cells. Drug targeting and therapeutic effect was investigated in BBB model. The result confirmed that liposome nanocarrier is required as a drug carrier for effectively RTX across the BBB.

A Personal Electronic Health Record: Study Protocol of a Feasibility Study on Implementation in a Real-World Health Care Setting

Background

A significant potential for patient empowerment is seen in concepts aiming to give patients access to their personal health information (PHI) and to share this PHI across different care settings and health systems. Personal health records (PHRs) and the availability of information through health information exchanges are considered to be key components of effective and efficient health care. With tethered PHRs, as often used in the United States, patients’ opportunities to manage their PHI are strongly restricted. Therefore, within the INFOPAT (information technology for patient oriented care) project (2012-2016) in Germany, funded by the Federal Ministry of Education and Research (BMBF), the development of a patient-controlled “personal electronic health record” (PEPA) was based on user requirements right from the beginning.

Objective

The overall objective of the study is to implement and evaluate a PEPA prototype for patients with colorectal cancer who are treated at the National Center for Tumor Diseases in Heidelberg. To achieve this aim, this study has 2 parts: a pre-implementation study (phase 1) and an implementation study (phase 2). The pre-implementation study will include a usability evaluation of the PEPA approach and the consideration of organizational preconditions for the implementation. With the implementation study, we will evaluate the process of implementation (eg, barriers or facilitators), the need for organizational change (eg, processes of communication), and the impact on outcomes (eg, self-efficacy, involvement in care).

Methods

The pre-implementation study is based on a mixed methods approach and comprises qualitative and quantitative element according to our research aim. We will use a think-aloud method for the usability analysis. Additionally, participants will be asked to evaluate their overall satisfaction based on a standardized questionnaire, the System Usability Scale. For the analysis of preconditions, we will conduct semistructured personal interviews with, for example, patients, medical assistants, and physicians. Within the implementation study the outcome evaluation is planned as a prospective, 3-month, open-label “before and after” trial. Additionally, for the analysis of processes and the need for organizational change, we will conduct interviews with the participants (eg, patients, general practitioners, physicians) of the before and after trial.

Results

This project is part of the INFOPAT project, which is funded (2012-2016) by the Federal Ministry of Education and Research (BMBF). The enrolment was completed in July 2016. Data analysis is currently under way and the first results are expected to be submitted for publication at end of 2017.

Conclusions

Existing approaches of PHRs aim to give patients access to their treatment data. With the PEPA approach and this study, we go a step further: patients have access to their PHI and they can give other persons (eg, their general practitioner) access. With this approach, new possibilities for professional collaboration and the engagement of patients can arise.

[Cleaning and disinfection of surfaces in hospitals: Data on structure, process and result in the Frankfurt/Main Metropolitan Area]

INTRODUCTION

In addition to hand hygiene and reprocessing of medical products, cleaning and disinfection of surfaces is also an important issue in the prevention of germ transmission and by implication infections. Therefore, in 2014, the quality of the structure, process and result of surface preparation of all hospitals in Frankfurt am Main, Germany, was monitored.

METHODS

All 17 hospitals transferred information on the quality of structure. Process quality was obtained through direct observation during cleaning and disinfection of rooms and their plumbing units. Result quality was gained using the fluorescent method, i.e. marking surfaces with a fluorescent liquid and testing if this mark has been sufficiently removed by cleaning.

RESULTS

Structure quality: in all hospitals the employees were trained regularly. In 12 of them, the foremen had the required qualifications, in 6 hospitals unclarity as to the intersection of the cleaning and care services remained. In 14 hospitals only visible contamination was cleaned on the weekends, whereas complete cleaning was reported to take place in 12 hospitals on Saturdays and in 2 hospitals on Sundays. The contractually stipulated cleaning (observations specified in brackets) averaged 178 m(2)/h (148 m(2)/h) per patient room and 69 m(2)/h (33 m(2)/h) for bathrooms. Process quality: during process monitoring, various hand contact surfaces were prepared insufficiently. Result quality: 63 % of fluorescent markings were appropriately removed.

CONCLUSION

The need for improvement is given especially in the area of the qualification of the foremen and a in a clear definition of the intersection between cleaning and care services, as well as in the regulations for weekends and public holidays.

Trans-Atlantic exchanges have shaped the population structure of the Lyme disease agent Borrelia burgdorferi sensu stricto

The origin and population structure of Borrelia burgdorferi sensu stricto (s.s.), the agent of Lyme disease, remain obscure. This tick-transmitted bacterial species occurs in both North America and Europe. We sequenced 17 European isolates (representing the most frequently found sequence types in Europe) and compared these with 17 North American strains. We show that trans-Atlantic exchanges have occurred in the evolutionary history of this species and that a European origin of B. burgdorferi s.s. is marginally more likely than a USA origin. The data further suggest that some European human patients may have acquired their infection in North America. We found three distinct genetically differentiated groups: i) the outgroup species Borrelia bissettii, ii) two divergent strains from Europe, and iii) a group composed of strains from both the USA and Europe. Phylogenetic analysis indicated that different genotypes were likely to have been introduced several times into the same area. Our results demonstrate that irrespective of whether B. burgdorferi s.s. originated in Europe or the USA, later trans-Atlantic exchange(s) have occurred and have shaped the population structure of this genospecies. This study clearly shows the utility of next generation sequencing to obtain a better understanding of the phylogeography of this bacterial species.

[Hygiene in endoscopy in clinic and practice 2013 in comparison with 2003--structure and process quality]

BACKGROUND

Endoscopy is an important part of modern medical diagnostics and therapy. The invasive procedures are however associated with a risk to transmit infections. Against this background the KRINKO has published the "Hygienic requirements for the reprocessing of flexible endoscopes and endoscopic accessories" in 2002 and has updated these recommendations in 2012. In 2003 and 2013 all gastroenterological facilities in Frankfurt am Main using flexible endoscopes were monitored for compliance with the recommendations.

METHODS

The inspections were performed after prior notice by a staff member of the health authority using a checklist which had been developed on the basis of the current KRINKO recommendations.

RESULTS

In both years all institutions performing endoscopic procedures were visited: 2003 15 hospitals and 23 practices; 2013 14 clinics and 10 practices. In 2013 (data for 2003 in brackets) 100 % (93 %) of the hospitals and 60 % (22 %) of practices reprocessed their endoscopes by automated methods. The appropriate reprocessing and filling of water bottles for rinsing the scope channels with sterile water and the sterilisation of accessories were satisfactorily performed in 2003 and 2013 by all hospitals. However in 2013 only 90 % (2003: 74 %) of the practices correctly reprocessed water bottles and 80 % (52 %) used sterile water for filling the bottle. In 2013 100 % (2003: 57 %) of the practices correctly sterilised accessory instruments, while 2 practices used disposable, i. e., single-use materials. In 2013 all institutions performed microbiological tests according to KRINKO recommendations, while in 2003 all hospitals but only 43 % of the practices could present such tests.

DISCUSSION

While the gastroenterological departments of Frankfurt hospitals already complied with the KRINKO recommendations in 2003, the inspection of several practices in 2003 had revealed considerable shortcomings in the implementation of these recommendations. Subsequently the practices have improved their hygiene management.

Unresectable isolated hepatic metastases from solid pseudopapillary neoplasm of the pancreas: a case report of chemosaturation with high-dose melphalan

BACKGROUND/OBJECTIVES

Solid pseudopapillary neoplasms of the pancreas (SPN) are rare tumors. For patients with unresectable liver metastases of SPN, no standard treatment has been defined so far. Here we report a case of a 40-year-old woman with SPN and metastases confirmed to the liver, and disease progression in the liver after primary tumor resection and chemotherapy with gemcitabine and cisplatin.

METHODS

Chemosaturation with percutaneous hepatic perfusions is a minimally invasive, repeatable regional therapy which delivers chemotherapy directly to the liver while limiting systemic toxicity. As an individual treatment approach, the patient was treated with chemosaturation with percutaneous hepatic perfusions of melphalan.

RESULTS

The procedure was performed twice within 8 weeks after which the liver metastases showed a marked reduction in size and vascularization (partial response). Grade 3 leukopenia after the second procedure was managed effectively with granulocyte colony-stimulating factor. No other toxicities were observed. Ten months after initiating treatment, the patient had a good performance status and remained stable.

CONCLUSIONS

For SPN with unresectable liver metastases and progression despite systemic treatment, repeat chemosaturation with high-dose melphalan may also offer an effective regional treatment option.

Manufacture-Induced Inaccuracies of Spinning Dies1

The die in the melt spinning process distributes the whole melt stream into individual small melt streams that pass the die parallel to each other. The number of holes in the die determines the number of filaments in the spun fiber bundle. As the whole melt stream (i. e. the total throughput) is enforced by a precise gear pump (the spinning pump) the sharing out into the single hole throughputs is dependent on the pressure and the flow resistances of the single holes. Only for constant pressure and equal resistances the single hole throughputs are equal, too. The present paper deals with the influence of geometrical inaccuracies of the holes in the spinning die on the fineness and structural variations across the spun fiber bundle.

Graphical Tests for Power Comparison of Competing Designs

Lineups have been established as tools for visual testing similar to standard statistical inference tests, allowing us to evaluate the validity of graphical findings in an objective manner. In simulation studies lineups have been shown as being efficient: the power of visual tests is comparable to classical tests while being much less stringent in terms of distributional assumptions made. This makes lineups versatile, yet powerful, tools in situations where conditions for regular statistical tests are not or cannot be met. In this paper we introduce lineups as a tool for evaluating the power of competing graphical designs. We highlight some of the theoretical properties and then show results from two studies evaluating competing designs: both studies are designed to go to the limits of our perceptual abilities to highlight differences between designs. We use both accuracy and speed of evaluation as measures of a successful design. The first study compares the choice of coordinate system: polar versus cartesian coordinates. The results show strong support in favor of cartesian coordinates in finding fast and accurate answers to spotting patterns. The second study is aimed at finding shift differences between distributions. Both studies are motivated by data problems that we have recently encountered, and explore using simulated data to evaluate the plot designs under controlled conditions. Amazon Mechanical Turk (MTurk) is used to conduct the studies. The lineups provide an effective mechanism for objectively evaluating plot designs.

[Pathowiki. A free expert database for pathology]

The project Pathowiki (www.pathowiki.org) is a free expert database for texts, images, virtual slides and links to all subject areas of pathology in the internet. The aim of this project is to integrate all available information and media, in particular virtual microscopy, to achieve a fast overview of a relevant subject area. Here we present the project’s basic functions and applications and evaluate the project with respect to the ongoing digital developments in pathology.

Thin Film Growth using Ablation of Ceramics with a Lina-Spark™ Atomizer

A laser spark atomizer (LINA-SPARK™), LSA, has been used for preparing powder particles from SnO2, Al2O3 and ZrO2 ceramic specimen. It is shown that this technique can be used for preparing thin films by direct deposition on a substrate. The as-prepared powder can also be redispersed and deposited using ultrasonic nebulization (Pyrosol) deposition. The latter approach is especially suited for deposition of controlled-size and multicomponent thin films.

The coupling of the LSA to an induced coupled plasma (ICP) emission spectrometer is also discussed and compared with laser ablation. Generally powder particles produced from LSA present a narrower size distribution as powders prepared by laser ablation. As a result, the quantitative elemental analysis of solids are improved with full benefit of the sensitivity and detection limits of the ICP are lowered.

Nanostructured zinc sulphide phosphors

Zinc sulphide (ZnS) particles are efficient phosphors for application in flat-panel displays. Spherical ZnS particles were prepared by precipitation from a homogeneous solution. Nanoparticles of 20 to 40 nm having a very narrow size distribution could be synthesized by using complexing chelates such as acetate and acetylacetonate. Complexing of the precipitating cation with the anions present in the system lead to a limited concentration of free cations in the solution. This strongly influences the kinetics of the primary particle agglomeration/growth, resulting in nanometer-sized ZnS particles. Nanostructured ZnS synthesized in this way are polycrystalline particles composed of crystallites of 5–10 nm. The synthesis of very small, non-agglomerated, nanocrystalline particles in the 5–10 nm size range was also possible, making use of a strong complexing ligand (thioglycerol) during the synthesis. The synthesis of controlled monosized ZnS particles will be presented and discussed. The photoluminescence characteristics of ZnS make this material a suitable candidate as phosphor for application in low voltage display technology. The effect of Mn2+ doping on the luminescence characteristics of ZnS will also be discussed.

Tin Dioxide Nano-Powders for Gas Sensor Applications

SnO2 nanoparticles are of interest for gas sensor applications because the surface area is much larger compared to conventional powders. Thus, interactions between the material and the gases, which occur on the surface sites of the particles, are increased considerably. The preparation of SnO2 powders has been investigated following two forced precipitation systems: the hydrolysis reaction of SnC14 in an emulsion media and the hydrolysis reaction of Sn2+ in the presence of a complexing ligand (CH3COO−). Spherical nanoparticles in the 10 to 100 nm range and with a narrow size distribution were synthesized by both precipitating routes. In both cases, it has been demonstrated that the most important parameter which controlled the particle size was the nature of the associated anion. When this associated anion or ligand is able to form a strong complex with the colloidal subunits, a barrier against Van der Waals attraction is created which results in little growth. This greatly influences the agglomeration/growth kinetics during the precipitation. The effect of acetate chelating ligands which resulted in the SnO2 nano-powders formed of 5–10 nm crystallites will be presented and discussed. Preliminary results on the gas (N2, NO) adsorption studies on pellets formed from these powders are also presented.

Superparamagnetic Iron Oxide Nanoarticles for Biomedical Applications: a focus on PVA as a coating

Nanoscaled particles showing a superparamagnetic behavior have been intensively studied these past years for biomedical applications and water-based ferrofluids turned out to be promising candidates for various in vivo as well as in vitro applications. Nevertheless, the lack of well-defined particles remains an important problem. One of the major challenges is still the large-scale synthesis of particles with a narrow size distribution. In this work iron oxide nanoparticles are obtained by classical co-precipitation in a water-based medium and are subsequently coated with polyvinyl alcohol. The thus obtained ferrofluids are studied and a focus is made on their colloidal stability.

Androidal fat dominates in predicting cardiometabolic risk in postmenopausal women

We hypothesized that soy isoflavones would attenuate the anticipated increase in androidal fat mass in postmenopausal women during the 36-month treatment, and thereby favorably modify the circulating cardiometabolic risk factors: triacylglycerol, LDL-C, HDL-C, glucose, insulin, uric acid, C-reactive protein, fibrinogen, and homocysteine. We collected data on 224 healthy postmenopausal women at risk for osteoporosis (45.8–65 y, median BMI 24.5) who consumed placebo or soy isoflavones (80 or 120 mg/d) for 36 months and used longitudinal analysis to examine the contribution of isoflavone treatment, androidal fat mass, other biologic factors, and dietary quality to cardiometabolic outcomes. Except for homocysteine, each cardiometabolic outcome model was significant (overall P-values from ≤.0001 to .0028). Androidal fat mass was typically the strongest covariate in each model. Isoflavone treatment did not influence any of the outcomes. Thus, androidal fat mass, but not isoflavonetreatment, is likely to alter the cardiometabolic profile in healthy postmenopausal women.

Physical activity and gestational weight gain: a meta-analysis of intervention trials

BACKGROUND

high gestational weight gain (GWG) has been found to be associated with a number of adverse perinatal and long-term outcomes.

OBJECTIVES

we aimed to perform a systematic review and meta-analysis to find out whether physical activity in pregnancy might help avoid high GWG.

SEARCH STRATEGY

a literature search in relevant databases and an additional search by hand through bibliographies of various publications were performed.

SELECTION CRITERIA

we included randomised controlled trials on healthy women, with increased physical activity as the only intervention. GWG had to be documented for the intervention and control group separately.

DATA COLLECTION AND ANALYSIS

two reviewers independently extracted data and performed quality assessment. Data from the included trials were combined using a random-effects model. The effect size was expressed as mean difference (MD).

MAIN RESULTS

of 1380 studies identified, 12 trials met the inclusion criteria. In seven trials, GWG was lower in the exercise group compared with the control group, whereas five trials showed a lower GWG in the control groups. The meta-analysis resulted in an MD of GWG of -0.61 (95% CI: -1.17, -0.06), suggesting less GWG in the intervention groups compared with the control groups. We found no indication for publication bias or dose effects.

AUTHOR'S CONCLUSIONS

in summary, our analyses suggest that physical activity during pregnancy might be successful in restricting GWG.

Highly anisotropic decay rates of single quantum dots in photonic crystal membranes

We have measured the variation of the spontaneous emission rate with polarization for self-assembled single quantum dots in two-dimensional photonic crystal membranes. We observe a maximum anisotropy factor of 6 between the decay rates of the two bright exciton states. This large anisotropy is attributed to the substantially different projected local density of optical states for differently oriented dipoles in the photonic crystal.