354 research outputs found
Magnetic irreversibility and Verwey transition in nano-crystalline bacterial magnetite
The magnetic properties of biologically-produced magnetite nanocrystals
biomineralized by four different magnetotactic bacteria were compared to those
of synthetic magnetite nanocrystals and large, high quality single crystals.
The magnetic feature at the Verwey temperature, , was clearly seen in
all nanocrystals, although its sharpness depended on the shape of individual
nanoparticles and whether or not the particles were arranged in magnetosome
chains. The transition was broader in the individual superparamagnetic
nanoparticles for which , where is the superparamagnetic
blocking temperature. For the nanocrystals organized in chains, the effective
blocking temperature and the Verwey transition is sharply
defined. No correlation between the particle size and was found.
Furthermore, measurements of suggest that magnetosome chains
behave as long magnetic dipoles where the local magnetic field is directed
along the chain and this result confirms that time-logarithmic magnetic
relaxation is due to the collective (dipolar) nature of the barrier for
magnetic moment reorientation
Reaction of Titanocene Dichloride with Acetylenedicarboxylate
The reaction of Cp2TiCl2 with either the mono- or dipotassium salt of acetylenedicarboxylic acid (ADC) gives high yields of an insoluble orange product. The insoluble compound shows potential semiconductor behavior, as evidenced by an apparent bandgap in the orange region of the visible spectrum. Under N2 ,the compound decomposes at 238° C, eventually losing approximately 46% total mass up to 1350° C. The exothermic decomposition in air, beginning at 235° C, results in the formation of titanium oxides
Maternal Early Pregnancy Serum Metabolomics Profile and Abnormal Vaginal Bleeding as Predictors of Placental Abruption: A Prospective Study
Background & Objective
Placental abruption, an ischemic placental disorder, complicates about 1 in 100 pregnancies, and is an important cause of maternal and perinatal morbidity and mortality worldwide. Metabolomics holds promise for improving the phenotyping, prediction and understanding of pathophysiologic mechanisms of complex clinical disorders including abruption. We sought to evaluate maternal early pregnancy pre-diagnostic serum metabolic profiles and abnormal vaginal bleeding as predictors of abruption later in pregnancy.
Methods
Maternal serum was collected in early pregnancy (mean 16 weeks, range 15 to 22 weeks) from 51 abruption cases and 51 controls. Quantitative targeted metabolic profiles of serum were acquired using electrospray ionization liquid chromatography-mass spectrometry (ESI-LC-MS/MS) and the Absolute IDQ® p180 kit. Maternal sociodemographic characteristics and reproductive history were abstracted from medical records. Stepwise logistic regression models were developed to evaluate the extent to which metabolites aid in the prediction of abruption. We evaluated the predictive performance of the set of selected metabolites using a receiver operating characteristics (ROC) curve analysis and area under the curve (AUC).
Results
Early pregnancy vaginal bleeding, dodecanoylcarnitine/dodecenoylcarnitine (C12 / C12:1), and phosphatidylcholine acyl-alkyl C 38:1 (PC ae C38:1) strongly predict abruption risk. The AUC for these metabolites alone was 0.68, for early pregnancy vaginal bleeding alone was 0.65, and combined the AUC improved to 0.75 with the addition of quantitative metabolite data (P = 0.003).
Conclusion
Metabolomic profiles of early pregnancy maternal serum samples in addition to the clinical symptom, vaginal bleeding, may serve as important markers for the prediction of abruption. Larger studies are necessary to corroborate and validate these findings in other cohorts
Non-Conscious Influences on Consumer Choice
While consumer choice research has dedicated considerable research attention to aspects of choice that are deliberative and conscious, only limited attention has been paid to aspects of choice that occur outside of conscious awareness. We review relevant research that suggests that consumer choice is a mix of conscious and nonconscious influences, and argue that the degree to which nonconscious influences affect choice is much greater than many choice researchers believe. Across a series of research domains, these influences are found to include stimulus that are not consciously perceived by the consumer, nonconscious downstream effects of a consciously perceived stimuli or thought process, and decision processes that occur entirely outside of awareness
The Influences of Reproductive Status and Acute Stress on the Levels of Phosphorylated Mu Opioid Receptor Immunoreactivity in Rat Hippocampus
Opioids play a critical role in hippocampally dependent behavior and plasticity. In the hippocampal formation, mu opioid receptors (MOR) are prominent in parvalbumin (PARV) containing interneurons. Previously we found that gonadal hormones modulate the trafficking of MORs in PARV interneurons. Although sex differences in response to stress are well documented, the point at which opioids, sex, and stress interact to influence hippocampal function remains elusive. Thus, we used quantitative immunocytochemistry in combination with light and electron microscopy for the phosphorylated MOR (pMOR) at the SER375 carboxy-terminal residue in male and female rats to assess these interactions. In both sexes, pMOR-immunoreactivity (ir) was prominent in axons and terminals and in a few neuronal somata and dendrites, some of which contained PARV in the mossy fiber pathway region of the dentate gyrus (DG) hilus and CA3 stratum lucidum. In unstressed rats, the levels of pMOR-ir in the DG or CA3 were not affected by sex or estrous cycle stage. However, immediately following 30 min of acute immobilization stress (AIS), males had higher levels of pMOR-ir whereas females at proestrus and estrus (high estrogen stages) had lower levels of pMOR-ir within the DG. In contrast, the number and types of neuronal profiles with pMOR-ir were not altered by AIS in either males or proestrus females. These data demonstrate that although gonadal steroids do not affect pMOR levels at resting conditions, they are differentially activated both pre and postsynaptic MORs following stress. These interactions may contribute to the reported sex differences in hippocampally dependent behaviors in stressed animals
Cilostazol for Secondary Stroke Prevention: History, Evidence, Limitations, and Possibilities
Cilostazol is a phosphodiesterase III inhibitor with a long track record of safety that is FDA and EMA approved for the treatment of claudication in patients with peripheral arterial disease. In addition, cilostazol has been approved for secondary stroke prevention in several Asian countries based on trials that have demonstrated a reduction in stroke recurrence among patients with non-cardioembolic stroke. The onset of benefit appears after 60–90 days of treatment, which is consistent with cilostazol’s pleiotropic effects on platelet aggregation, vascular remodeling, blood flow, and plasma lipids. Cilostazol appears safe and does not increase the risk of major bleeding when given alone or in combination with aspirin or clopidogrel. Adverse effects such as headache, gastrointestinal symptoms and palpitations, however, contributed to a 6% increase in drug discontinuation among patients randomized to cilostazol in a large secondary stroke prevention trial (CSPS.com). Due to limitations of prior trials, such as open label design, premature trial termination, large loss to follow-up, lack of functional or cognitive outcome data, and exclusive enrollment in Asia, the existing trials have not led to a change in clinical practice or guidelines in Western countries. These limitations could be addressed by a double-blind placebo-controlled randomized trial conducted in a broader population. If positive, it would increase the evidence in support of long-term treatment with cilostazol for secondary prevention in the millions of patients worldwide who have suffered a non-cardioembolic ischemic stroke
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Which outcomes are most important to people with aphasia and their families? an international nominal group technique study framed within the ICF
PURPOSE: To identify important treatment outcomes from the perspective of people with aphasia and their families using the ICF as a frame of reference.
METHODS: The nominal group technique was used with people with aphasia and their family members in seven countries to identify and rank important treatment outcomes from aphasia rehabilitation. People with aphasia identified outcomes for themselves; and family members identified outcomes for themselves and for the person with aphasia. Outcomes were analysed using qualitative content analysis and ICF linking.
RESULTS: A total of 39 people with aphasia and 29 family members participated in one of 16 nominal groups. Inductive qualitative content analysis revealed the following six themes: (1) Improved communication; (2) Increased life participation; (3) Changed attitudes through increased awareness and education about aphasia; (4) Recovered normality; (5) Improved physical and emotional well-being; and (6) Improved health (and support) services. Prioritized outcomes for both participant groups linked to all ICF components; primary activity/participation (39%) and body functions (36%) for people with aphasia, and activity/participation (49%) and environmental factors (28%) for family members. Outcomes prioritized by family members relating to the person with aphasia, primarily linked to body functions (60%).
CONCLUSIONS: People with aphasia and their families identified treatment outcomes which span all components of the ICF. This has implications for research outcome measurement and clinical service provision which currently focuses on the measurement of body function outcomes. The wide range of desired outcomes generated by both people with aphasia and their family members, highlights the importance of collaborative goal setting within a family-centred approach to rehabilitation. These results will be combined with other stakeholder perspectives to establish a core outcome set for aphasia treatment research. Implications for Rehabilitation Important outcomes for people with aphasia and their families span all components of the ICF. The relevancy and translation of research findings may be increased by measuring and reporting research outcomes which are important to people living with aphasia. The results of this study indicate that important treatment outcomes for people living with aphasia most frequently link to the activity/participation and body function components of the ICF. The outcomes identified in this study suggest a broad role for clinicians working in aphasia rehabilitation. The categories of identified outcomes may be used clinically as a starting point in goal-setting discussions with clients and their families
Intracranial Stenosis: Impact of Randomized Trials on Treatment Preferences of US Neurologists and Neurointerventionists
Medical and endovascular treatment options for stroke prevention in patients with symptomatic intracranial stenosis have evolved over the past several decades, but the impact of 2 major multi-center randomized stroke prevention trials on physician practices has not been studied. We sought to determine changes in US physician treatment choices for patients with intracranial atherosclerotic stenosis (ICAS) following 2 NIH-funded clinical trials that studied medical therapies (antithrombotic agents and risk factor control) and percutaneous transluminal angioplasty and stenting (PTAS)
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