753 research outputs found
Toward the systematic identification of microplastics in the environment: evaluation of a new independent software tool (siMPle) for spectroscopic analysis
Microplastics (MP) are ubiquitous within the environment, but the analysis of this contaminant is currently quite diverse, and a number of analytical methods are available. The comparability of results is hindered as even for a single analytical method such as Fourier transform infrared spectroscopy (FT-IR) the different instruments currently available do not allow a harmonized analysis. To overcome this limitation, a new free of charge software tool, allowing the systematic identification of MP in the environment (siMPle) was developed. This software tool allows a rapid and harmonized analysis of MP across FT-IR systems from different manufacturers (Bruker Hyperion 3000, Agilent Cary 620/670, PerkinElmer Spotlight 400, Thermo Fischer Scientific Nicolet iN10). Using the same database and the automated analysis pipeline (AAP) in siMPle, MP were identified in samples that were analyzed with instruments with different detector systems and optical resolutions, the results of which are discussed
The fate of cerium oxide nanoparticles in sediments and their routes of uptake in a freshwater worm
The relative importance of ingestion and transdermal uptake of nanomaterials is poorly understood, particularly in sediment dwelling organisms, where diet has the potential to contribute significantly to particle accumulation. In aquatic sediments, nanoparticles may partition to bind with the solid fraction of sediment, be freely mobile in the pore water or, for certain metal/metal oxides, undergo dissolution, each of which could influence the route of nanoparticle uptake. Here, we used the freshwater worm Lumbriculus variegatus as a model species. We took advantage of its unique feeding and non-feeding life-stages to assess the contribution of dietary and transdermal uptake in the bioaccumulation of cerium oxide nanoparticles (CeO2 NP) and soluble Ce(III)NO3. Distribution of cerium between the solid, colloidal and soluble fractions in the sediments was determined through sediment separations using micro and ultrafiltration techniques. We assessed particles of differing sizes (10, 28 and 615 nm CeO2) and stabilizing surfactants (10 nm electrostatic Citrate-CeO2 and steric stabilized PEG-CeO2). Soluble Ce(III)NO3, was found to accumulate readily across the skin of the worms whilst nanoparticles were not. Sediments reduced the uptake of CeIII by limiting the presence of dissolved species of cerium in the pore waters. Neither particle size nor the coatings studied altered the distribution of nanoparticles between solid and colloidal fractions of the sediment, with ∼99% associated to the solid phase. Any uptake of CeO2 nanoparticles into worms was only through ingestion. Stabilized 10 nm particles were retained even after gut clearance, indicating that these particles may translocate across the gut wall
Emotional Climate, Feeding Practices, and Feeding Styles: An Observational Analysis of the Dinner Meal in Head Start Families
BACKGROUND: A number of studies conducted with ethnically diverse, low-income samples have found that parents with indulgent feeding styles had children with a higher weight status. Indulgent parents are those who are responsive to their child\u27s emotional states but have problems setting appropriate boundaries with their child. Because the processes through which styles impact child weight are poorly understood, the aim of this study was to observe differences in the emotional climate created by parents (including affect, tone of voice, and gestures) and behavioral feeding practices among those reporting different feeding styles on the Caregiver\u27s Feeding Styles Questionnaire. A secondary aim was to examine differences on child weight status across the feeding styles.
METHODS: Participants were 177 Head Start families from Houston, Texas (45% African-American; 55% Hispanic). Using an observational approach, the relationship between the observed emotional climate of the meal, behavioral feeding practices, and self-reported parent feeding styles were examined. Mean age of the children was 4.4 years (SD = 0.7) equally distributed across gender. Families were observed on 3 separate dinner occasions. Heights and weight were measured on the parents and children.
RESULTS: Parents with self-reported indulgent feeding styles made fewer demands on their children to eat during dinner and showed lower levels of negative affect and intrusiveness. Surprisingly, these parents also showed higher levels of emotional detachment with their children during dinner. Hispanic boys with indulgent parents had significantly higher BMI z scores compared to Hispanic boys in the other three feeding style groups. No other differences were found on child weight status.
CONCLUSIONS: Results suggest that the emotional climate created by indulgent parents during dinner and their lack of demands on their children to eat may play an important role in how young children become overweight. Numerous observed emotional climate and behavioral differences were found between the other self-reported feeding styles as well. Results suggest that parents\u27 self-reported feeding styles may be a proxy for the emotional climate of the dinner meal, which may in turn influence the child\u27s eating behaviors and weight status
Facile Preparation of Drug-Loaded Tristearin Encapsulated Superparamagnetic Iron Oxide Nanoparticles Using Coaxial Electrospray Processing
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link
Similarity assessment of metallic nanoparticles within a risk assessment framework: a case study on metallic nanoparticles and lettuce
Similarity assessment is one of the means of optimally using scarcely available experimental data on the fate and hazards of nanoforms (NFs) for regulatory purposes. For a set of NFs that are shown to be similar it is allowed in a regulatory context to apply the information available on any of the NFs within the group to the whole set of NFs. Obviously, a proper justification for such a similarity assessment is to be provided. Within the context of exemplifying such a justification, a case study was performed aimed at assessing the similarity of a set of spherical metallic NFs that different with regard to chemical composition (three metals) and particle size (three different sizes). The endpoints of assessment were root elongation and biomass increase of lettuce (Lactuca sativa L.) seedlings and exposure assessment was performed in order to express the actual exposure concentration in terms of time-weighted average particle concentrations. The results of the study show that for the specific endpoints assessed, chemical composition is driving NF toxicity and this is mostly due to impacts on the fate of the NFs. On the other hand, particle size of Cu NFs had a negligible impact on the dose-response relationships for the specific endpoints assessed. It is thus concluded that hazard data available on spherical Cu NF tested in our case can be used to inform on the hazards of any spherical Cu NF within the size range of 25–100 nm, but only applies for the certain endpoints. Also, toxicity data for the Cu2+-ion are suited for such a similarity assessment
Many-body physics of a quantum fluid of exciton-polaritons in a semiconductor microcavity
Some recent results concerning nonlinear optics in semiconductor
microcavities are reviewed from the point of view of the many-body physics of
an interacting photon gas. Analogies with systems of cold atoms at thermal
equilibrium are drawn, and the peculiar behaviours due to the non-equilibrium
regime pointed out. The richness of the predicted behaviours shows the
potentialities of optical systems for the study of the physics of quantum
fluids.Comment: Proceedings of QFS2006 conference to appear on JLT
fMRI evidence of ‘mirror’ responses to geometric shapes
Mirror neurons may be a genetic adaptation for social interaction [1]. Alternatively, the associative hypothesis [2], [3] proposes that the development of mirror neurons is driven by sensorimotor learning, and that, given suitable experience, mirror neurons will respond to any stimulus. This hypothesis was tested using fMRI adaptation to index populations of cells with mirror properties. After sensorimotor training, where geometric shapes were paired with hand actions, BOLD response was measured while human participants experienced runs of events in which shape observation alternated with action execution or observation. Adaptation from shapes to action execution, and critically, observation, occurred in ventral premotor cortex (PMv) and inferior parietal lobule (IPL). Adaptation from shapes to execution indicates that neuronal populations responding to the shapes had motor properties, while adaptation to observation demonstrates that these populations had mirror properties. These results indicate that sensorimotor training induced populations of cells with mirror properties in PMv and IPL to respond to the observation of arbitrary shapes. They suggest that the mirror system has not been shaped by evolution to respond in a mirror fashion to biological actions; instead, its development is mediated by stimulus-general processes of learning within a system adapted for visuomotor control
Co-occurrence of macroplastics, microplastics, and legacy and emerging plasticisers in UK soils
Despite a theoretical link between plastic and plasticiser occurrence in the terrestrial environment, there are few empirical studies of the relationship between these contaminants in soils. We carried out a field study to assess the cooccurrence of plastic waste, and legacy and emerging plasticisers in UK soils (n = 19) from various land uses (woodlands, urban roadsides, urban parklands, landfill-associated). Surface plastics and soil microplastics were quantified and characterised using ATR-FTIR and μ-FTIR. Eight legacy (phthalate) and three emerging (adipate, citrate, trimellitate) plasticisers were quantified using GC–MS. Surface plastics were found at higher prevalence at landfillassociated and urban roadside sites, with levels significantly (2 orders of magnitude) greater than in woodlands. Microplastics were detected in landfill-associated (mean 12.3 particles g−1 dw), urban roadside (17.3 particles g−1dw) and urban parkland (15.7 particles g−1 dw) soils, but not in woodland soils. The most commonly detected polymers were polyethene, polypropene and polystyrene. Mean ∑plasticiser concentration in urban roadside soils (3111 ng g−1 dw) was significantly higher than in woodlands (134 ng g−1 dw). No significant difference was found between landfill-associated (318 ng g−1 dw) and urban parkland (193 ng g−1 dw) soils and woodlands. Di-n-butyl phthalate (94.7% detection frequency) and the emerging plasticiser trioctyl trimellitate (89.5%) were the most commonly detected plasticisers, with diethylhexyl phthalate (493 ng g−1 dw) and di-iso-decyl phthalate (96.7 ng g−1
dw) present at the highest concentrations. ∑plasticiser concentrations were significantly correlated with surface plastic (R2 = 0.23), but not with soil microplastic concentrations. Whilst plastic litter seems a fundamental source of plasticisers in soils, mechanisms such as airborne transport from source areas may be as important. Based on the data from this study, phthalates remain the dominant plasticisers in soils, but emerging plasticisers are already widespread, as reflected by their presence in all land uses studied
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Access to Cancer Care in Kenya: Patients’, Survivors’, Caregivers’ and Health Providers’ Perspectives
Access to health care remains a complex notion with varying interpretations and no universally accepted definition. At least half of the world’s population lacks access to essential health services. The literature identifies “6As” dimensions of Access: Accessibility, Affordability, Availability, Adequacy /Appropriateness, Acceptability and Approachability. This paper employs these dimensions in documenting factors that were found to influence access to cancer care in Kenya. Health and Industry studies were conducted sequentially. The health part of the study reported in this working paper, employed a convergent parallel mixed methods study design which was undertaken in three counties of Meru, Nairobi and Mombasa. A total of 405 patients were interviewed in public sector health facilities, four focus group discussions with cancer survivors and 22 in-depth interviews with caregivers, health workers and policy makers held.
Affordability of cancer services was enabled largely by cash payment with incremental use of National Hospital Insurance Fund (NHIF) from entry in health care up to the first treatment, but the high costs of cancer services were a major challenge. Payments for tests, treatment and indirect costs including transport and accommodation potentially impoverished many patients and their families as well as social networks . Facilities were financially supported by County Government funding, business and non-profit partners, and collaborations between health facilities to reduce indirect costs for the patients. Approachability was facilitated by community outreach services, local networks, awareness and knowledge promotion. However, better linkage between the community and health facility was required, especially for screening services. Availability: 30% of survey participants indicated that something they needed at the health facility was unavailable. The missing items included: medication, tests, treatment therapies, pain relief and essential commodities. Qualitative findings identified additional requirements including oncology staff and equipment. Patients also considered aspects of care that were unacceptable, and mentioned fear, stigma, cultural influences, religious and alternative beliefs. Nonetheless, having information and support from family, friends and other patient’s facilitated acceptability of cancer services. Accessibility in terms of distance and time to reach cancer care services located at county or national referral facilities was reported as a challenge for many. Communication, including lack of clarity, mis-diagnosis and non-disclosure of relevant information emerged as an appropriateness concern.
It is important to note that the six access dimensions interact and therefore, may not be addressed separately. When these aspects of access to cancer care are facilitated, then access can be improved. Hence, a holistic health system approach to access is desirable, while emphasis should be put on enhancing diagnostic capabilities at lower levels of care in line with the objective of Universal Health Coverage. Mutually supportive interventions to strengthen access can include wider insurance coverage, extended staffing and improved information. When challenges to any of the access dimensions remain, then access to cancer care is undermined
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