520 research outputs found
Identification of senescence and death in Emiliania huxleyi and Thalassiosira pseudonana: Cell staining, chlorophyll alterations, and dimethylsulfoniopropionate (DMSP) metabolism
We measured membrane permeability, hydrolytic enzyme, and caspase-like activities using fluorescent cell stains to document changes caused by nutrient exhaustion in the coccolithophore Emiliania huxleyi and the diatom Thalassiosira pseudonana, during batch-culture nutrient limitation. We related these changes to cell death, pigment alteration, and concentrations of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) to assess the transformation of these compounds as cell physiological condition changes. E. huxleyi persisted for 1 month in stationary phase; in contrast, T. pseudonana cells rapidly declined within 10 d of nutrient depletion. T. pseudonana progressively lost membrane integrity and the ability to metabolize 5-chloromethylfluorescein diacetate (CMFDA; hydrolytic activity), whereas E. huxleyi developed two distinct CMFDA populations and retained membrane integrity (SYTOX Green). Caspase-like activity appeared higher in E. huxleyi than in T. pseudonana during the post-growth phase, despite a lack of apparent mortality and cell lysis. Photosynthetic pigment degradation and transformation occurred in both species after growth; chlorophyll a (Chl a) degradation was characterized by an increase in the ratio of methoxy Chl a : Chl a in T. pseudonana but not in E. huxleyi, and the increase in this ratio preceded loss of membrane integrity. Total DMSP declined in T. pseudonana during cell death and DMS increased. In contrast, and in the absence of cell death, total DMSP and DMS increased in E. huxleyi. Our data show a novel chlorophyll alteration product associated with T. pseudonana death, suggesting a promising approach to discriminate nonviable cells in nature
The prevalence of visual anomalies among adult offenders
Fifty-three incarcerated adult sexual offenders from a voluntary treatment program at the Oregon State Correctional Facility were screened for visual anomalies. Subjects were divided into two groups based on intellectual function, one a higher functioning (HF) group, and one a social skills (SS) group. The two groups were compared based on a screening battery probing ocular health, eye movement skills, visual perceptual abilities and accommodative/vergence abilities. The ocular health did not differ between the two groups or from the general population. Differences were found in visual perceptual function between the high and low functioning groups. The HF group outperformed the lower on all perceptual and eye movement tests except the subjective eye movement evaluation. Unexpected differences were found between the two groups in the areas of accommodative posture, vergence facility, and distance monocular acuities
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LENS Deposition of Complex Geometries
The Laser Engineered Net Shaping (LENS®) system at Sandia National Laboratories, a
laser-based direct metal deposition process, was recently used for the fabrication of a complex
prototype. The LENS process involved the challenges of adjacent areas of thick and thin cross
section, overhanging unsupported features, high aspect ratios, and a hemispherical substrate.
These challenges were overcome through the use of closed-loop weld pool control, height
monitoring, a strong understanding of build parameters, and unique process planning strategies.
The near-net shape LENS part was completed with annealing and conventional machining to
produce the complex components in a reduced timeframe.Mechanical Engineerin
Can oral healthcare for older people be embedded into routine community aged care practice? A realist evaluation using normalisation process theory
This author accepted manuscript is made available following 12 month embargo from date of publication (December 2018) in accordance with the publisher’s archiving policyBackground
An intervention ‘Better Oral Health in Home Care’ was introduced (2012–2014) to improve the oral health of older people receiving community aged care services. Implementation of the intervention was theoretically framed by the Promoting Action on Research Implementation in Health Services framework. Process outcomes demonstrated significant improvements in older people’s oral health.
Objective
To evaluate the extent to which the intervention has been embedded and sustained into routine community aged care practice 3 years after the initial implementation project.
Design
A Realist Evaluation applying Normalisation Process Theory within a single case study setting.
Setting
Community aged care (home care) provider in South Australia, Australia.
Participants
Purposeful sampling was undertaken. Twelve staff members were recruited from corporate, management and direct care positions. Two consumers representing high and low care recipients also participated.
Methods
Qualitative methods were applied in two subcases, reflecting different contextual settings. Data were collected via semi-structured interviews and analysed deductively by applying the Normalisation Process Theory core constructs (with the recommended phases of the Realist Evaluation cycle). Retrospective and prospective analytic methods investigated how the intervention has been operationalised by comparing two timeframes: Time 1 (Implementation June 2012–December 2014) and Time 2 (Post-implementation July 2017–July 2018).
Results
At Time 1, the initial program theory proposed that multi-level facilitation contributed to a favourable context that triggered positive mechanisms supportive of building organisational and workforce oral healthcare capacity. At Time 2, an alternative program theory of how the intervention has unfolded in practice described a changed context following the withdrawal of the project facilitation processes with the triggering of alternative mechanisms that have made it difficult for staff to embed sustainable practice.
Conclusion
Findings concur with the literature that successful implementation outcomes do not necessarily guarantee sustainability. The study has provided a deeper explanation of how contextual characteristics have contributed to the conceptualisation of oral healthcare as a low priority, basic work-ready personal care task and how this, in turn, hindered the embedding of sustainable oral healthcare into routine community aged care practice. This understanding can be used to better inform the development of strategies, such as multi-level facilitation, needed to navigate contextual barriers so that sustainable practice can be achieved
Obstructive hydrocephalus and intracerebral mass secondary to Epicoccum nigrum
Here we report a case of a 14-week-old girl with a history of intrauterine drug exposure and hypoxic ischemic encephalopathy secondary to cardiac arrest requiring prolonged resuscitation at birth presented with irritability and a bulging anterior fontanelle. After neurosurgical resection, pathologic examination showed fungal hyphae, an
Using Empirical Phase Diagrams to Understand the Role of Intramolecular Dynamics in Immunoglobulin G Stability
Understanding the relationship between protein dynamics and stability is of paramount importance to the fields of biology and pharmaceutics. Clarifying this relationship is complicated by the large amount of experimental data that must be generated and analyzed if motions that exist over the wide range of timescales are to be included. To address this issue, we propose an approach that utilizes a multidimensional vector-based empirical phase diagram (EPD) to analyze a set of dynamic results acquired across a temperature-pH perturbation plane. This approach is applied to a humanized immunoglobulin G1 (IgG1), a protein of major biological and pharmaceutical importance whose dynamic nature is linked to its multiple biological roles. Static and dynamic measurements are used to characterize the IgG and to construct both static and dynamic empirical phase diagrams. Between pH 5 and 8, a single, pH-dependent transition is observed that corresponds to thermal unfolding of the IgG. Under more acidic conditions, evidence exists for the formation of a more compact, aggregation resistant state of the immunoglobulin, known as A-form. The dynamics-based EPD presents a considerably more detailed pattern of apparent phase transitions over the temperature-pH plane. The utility and potential applications of this approach are discussed
Ampullary cancers harbor ELF3 tumor suppressor gene mutations and exhibit frequent WNT dysregulation
The ampulla of Vater is a complex cellular environment from which adenocarcinomas arise to form a group of histopathologically heterogenous tumors. To evaluate the molecular features of these tumors, 98 ampullary adenocarcinomas were evaluated and compared to 44 distal bile duct and 18 duodenal adenocarcinomas. Genomic analyses revealed mutations in the WNT signaling pathway among half of the patients and in all three adenocarcinomas irrespective of their origin and histological morphology. These tumors were characterized by a high frequency of inactivating mutations of ELF3, a high rate of microsatellite instability, and common focal deletions and amplifications, suggesting common attributes in the molecular pathogenesis are at play in these tumors. The high frequency of WNT pathway activating mutation, coupled with small-molecule inhibitors of β-catenin in clinical trials, suggests future treatment decisions for these patients may be guided by genomic analysis
Characterization of lethal inhalational infection with Francisella tularensis in the common marmoset (Callithrix jacchus)
The intracellular Gram-negative pathogen Francisella tularensis is the causative agent of tularaemia and is prevalent in many countries in the northern hemisphere. To determine whether the common marmoset (Callithrix jacchus) would be a suitable non-human primate model of inhalational tularaemia, a pathophysiology study was undertaken. Ten animals were challenged with ∼102 c.f.u. F. tularensis strain SCHU S4 (F. tularensis subsp. tularensis). To look for trends in the infection, pairs of animals were sacrificed at 24 h intervals between 0 and 96 h post-challenge and blood and organs were assessed for bacteriology, pathology and haematological and immunological parameters. The first indication of infection was a raised core temperature at 3 days post-challenge. This coincided with a number of other factors: a rapid increase in the number of bacteria isolated from all organs, more pronounced gross pathology and histopathology, and an increase in the immunological response. As the disease progressed, higher bacterial and cytokine levels were detected. More extensive pathology was observed, with multifocal lesions seen in the lungs, liver and spleen. Disease progression in the common marmoset appears to be consistent with human clinical and pathological features of tularaemia, indicating that this may be a suitable animal model for the investigation of novel medical interventions such as vaccines or therapeutics
Crystallization and characterization of the thallium form of the Oxytricha nova G-quadruplex
The crystal structure of the Tl(+) form of the G-quadruplex formed from the Oxytricha nova telomere sequence, d(G(4)T(4)G(4)), has been solved to 1.55 Å. This G-quadruplex contains five Tl(+) ions, three of which are interspersed between adjacent G-quartet planes and one in each of the two thymine loops. The structure displays a high degree of similarity to the K(+) crystal structure [Haider et al. (2002), J. Mol. Biol., 320, 189–200], including the number and location of the monovalent cation binding sites. The highly isomorphic nature of the two structures, which contain such a large number of monovalent binding sites (relative to nucleic acid content), verifies the ability of Tl(+) to mimic K(+) in nucleic acids. Information from this report confirms and extends the assignment of (205)Tl resonances from a previous report [Gill et al. (2005), J. Am. Chem. Soc., 127, 16 723–16 732] where (205)Tl NMR was used to study monovalent cation binding to this G-quadruplex. The assignment of these resonances provides evidence for the occurrence of conformational dynamics in the thymine loop region that is in slow exchange on the (205)Tl timescale
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