5,777 research outputs found

    Intact and Top-Down Characterization of Biomolecules and Direct Analysis Using Infrared Matrix-Assisted Laser Desorption Electrospray Ionization Coupled to FT-ICR Mass Spectrometry

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    We report the implementation of an infrared laser onto our previously reported matrix-assisted laser desorption electrospray ionization (MALDESI) source with ESI post-ionization yielding multiply charged peptides and proteins. Infrared (IR)-MALDESI is demonstrated for atmospheric pressure desorption and ionization of biological molecules ranging in molecular weight from 1.2 to 17 kDa. High resolving power, high mass accuracy single-acquisition Fourier transform ion cyclotron resonance (FT-ICR) mass spectra were generated from liquid- and solid-state peptide and protein samples by desorption with an infrared laser (2.94 μm) followed by ESI post-ionization. Intact and top-down analysis of equine myoglobin (17 kDa) desorbed from the solid state with ESI post-ionization demonstrates the sequencing capabilities using IR-MALDESI coupled to FT-ICR mass spectrometry. Carbohydrates and lipids were detected through direct analysis of milk and egg yolk using both UV- and IR-MALDESI with minimal sample preparation. Three of the four classes of biological macromolecules (proteins, carbohydrates, and lipids) have been ionized and detected using MALDESI with minimal sample preparation. Sequencing of O-linked glycans, cleaved from mucin using reductive β-elimination chemistry, is also demonstrated. © 2009 American Society for Mass Spectrometry

    The Human Rights of Older People With Mental Health Conditions and Psychosocial Disability to a Good Death and Dying Well

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    The human right to a good death and dying well is as important as the right to life. At stake at the end of life are human rights to dignity, autonomy, self-determination and respect for will and preferences, equitable access to quality health care that is needs-based, and respect for family and relationships. Older people with dementia, those with serious mental illness, and those with intellectual disability are vulnerable to "bad deaths" due to violations of these rights. In this paper we explore why this is so and examine existing and potential solutions. A human rights-approach to end-of-life care and policy for older persons with mental health conditions and psychosocial disability is one that is needs-based, encompassing physical and mental health, palliative care, social, and spiritual support services provided in the context of inclusive living. Most importantly, end of life care must be self-determined, and not "one size fits all." An important remedy to existing violations is to strengthen human rights frameworks to cater specifically to older persons' needs with a UN convention on the rights of older persons. Finally, as health professionals we have important contributions to make at the coalface by accepting our responsibilities in the area of death and dying. With the concept of the palliative psychiatrist gaining traction and recognition that death is our business, we add that human rights is also our business

    Generic bounds on dipolar gravitational radiation from inspiralling compact binaries

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    Various alternative theories of gravity predict dipolar gravitational radiation in addition to quadrupolar radiation. We show that gravitational wave (GW) observations of inspiralling compact binaries can put interesting constraints on the strengths of the dipole modes of GW polarizations. We put forward a physically motivated gravitational waveform for dipole modes, in the Fourier domain, in terms of two parameters: one which captures the relative amplitude of the dipole mode with respect to the quadrupole mode (α\alpha) and the other a dipole term in the phase (β\beta). We then use this two parameter representation to discuss typical bounds on their values using GW measurements. We obtain the expected bounds on the amplitude parameter α\alpha and the phase parameter β\beta for Advanced LIGO (AdvLIGO) and Einstein Telescope (ET) noise power spectral densities using Fisher information matrix. AdvLIGO and ET may at best bound α\alpha to an accuracy of 102\sim10^{-2} and 103\sim10^{-3} and β\beta to an accuracy of 105\sim10^{-5} and 106\sim10^{-6} respectively.Comment: Matches with the published versio

    The ROTSE-III Robotic Telescope System

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    The observation of a prompt optical flash from GRB990123 convincingly demonstrated the value of autonomous robotic telescope systems. Pursuing a program of rapid follow-up observations of gamma-ray bursts, the Robotic Optical Transient Search Experiment (ROTSE) has developed a next-generation instrument, ROTSE-III, that will continue the search for fast optical transients. The entire system was designed as an economical robotic facility to be installed at remote sites throughout the world. There are seven major system components: optics, optical tube assembly, CCD camera, telescope mount, enclosure, environmental sensing & protection and data acquisition. Each is described in turn in the hope that the techniques developed here will be useful in similar contexts elsewhere.Comment: 19 pages, including 4 figures. To be published in PASP in January, 2003. PASP Number IP02-11

    Gut-seeded α-synuclein fibrils promote gut dysfunction and brain pathology specifically in aged mice

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    Parkinson’s disease is a synucleinopathy that is characterized by motor dysfunction, death of midbrain dopaminergic neurons and accumulation of α-synuclein (α-Syn) aggregates. Evidence suggests that α-Syn aggregation can originate in peripheral tissues and progress to the brain via autonomic fibers. We tested this by inoculating the duodenal wall of mice with α-Syn preformed fibrils. Following inoculation, we observed gastrointestinal deficits and physiological changes to the enteric nervous system. Using the AAV-PHP.S capsid to target the lysosomal enzyme glucocerebrosidase for peripheral gene transfer, we found that α-Syn pathology is reduced due to the increased expression of this protein. Lastly, inoculation of α-Syn fibrils in aged mice, but not younger mice, resulted in progression of α-Syn histopathology to the midbrain and subsequent motor defects. Our results characterize peripheral synucleinopathy in prodromal Parkinson’s disease and explore cellular mechanisms for the gut-to-brain progression of α-Syn pathology

    How do factors of sociodemographic, health literacy and dementia experience influence carers' knowledge of dementia?

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    BACKGROUND: Dementia is a life limiting disease following a progressive trajectory. As carers often become key decision makers, their knowledge of dementia will have health implications for the person living with dementia as well as carer’s psychological wellbeing. AIM: To explore how sociodemographic factors, health literacy and dementia experience influence family carers knowledge about dementia. METHOD: In this cross-sectional, mixed methods study, we interviewed 150 family carers and assessed their dementia knowledge using the Dementia Knowledge Assessment Scale (DKAS). Linear regression analyses were used to examine whether health literacy, previous experiences of dementia, support group attendance and sociodemographic characteristics predicted knowledge. Sixteen carers also completed qualitative interviews which explored unmet information needs. Transcripts and field notes were thematically analysed. RESULTS: Most participants were partners (47%) or adult children (48%) and cared for someone with severe (32%) or moderate (43%) dementia. Mean DKAS scores were 34.8/50 (SD = 7.0, range = 17–48) reflecting 8/25 incorrect answers. Backwards elimination regression found greater dementia knowledge was associated with greater health literacy for appraising information (coef 3.48, 95% CI (1.38, 5.58); p = 0.001) and more years of education (coef 0.39, 95% CI (0.12, 0.65); p = 0.004). Although not significant, knowledge was slightly lower in those who attended a support group, and a trend was found between ability to understand health information and knowledge. Only 39% accurately identified dementia as life shortening, indicating notable gaps in knowledge. Four qualitative themes were identified; arm yourself with information, ability to steer through information, other experience of dementia can be helpful and the importance of relationships with health care professionals. CONCLUSIONS: In an information age, vast amounts of information are available, but this can bring difficulties. Carers with more years of education and higher health literacy knew more about dementia. Professionals should consider how carers with lower health literacy can be supported through provision of timely, relevant information

    Atomic data from the IRON Project. I. Electron-impact scattering of Fe17+ using <I>R</I>-matrix theory with intermediate coupling

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    We present results for electron-impact excitation of F-like Fe calculated using R-matrix theory where an intermediate-coupling frame transformation (ICFT) is used to obtain level-resolved collision strengths. Two such calculations are performed, the first expands the target using 2s2 2p5, 2s 2p6, 2s2 2p4 3l, 2s 2p5 3l, and 2p6 3l configurations while the second calculation includes the 2s2 2p4 4l, 2s 2p5 4l, and 2p6 4l configurations as well. The effect of the additional structure in the latter calculation on the n=3 resonances is explored and compared with previous calculations. We find strong resonant enhancement of the effective collision strengths to the 2s2 2p4 3s levels. A comparison with a Chandra X-ray observation of Capella shows that the n=4 R-matrix calculation leads to good agreement with observation</p

    Quantitative micro-elastography: imaging of tissue elasticity using compression optical coherence elastography

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    Probing the mechanical properties of tissue on the microscale could aid in the identification of diseased tissues that are inadequately detected using palpation or current clinical imaging modalities, with potential to guide medical procedures such as the excision of breast tumours. Compression optical coherence elastography (OCE) maps tissue strain with microscale spatial resolution and can delineate microstructural features within breast tissues. However, without a measure of the locally applied stress, strain provides only a qualitative indication of mechanical properties. To overcome this limitation, we present quantitative micro-elastography, which combines compression OCE with a compliant stress sensor to image tissue elasticity. The sensor consists of a layer of translucent silicone with well-characterized stress-strain behaviour. The measured strain in the sensor is used to estimate the two-dimensional stress distribution applied to the sample surface. Elasticity is determined by dividing the stress by the strain in the sample. We show that quantification of elasticity can improve the ability of compression OCE to distinguish between tissues, thereby extending the potential for inter-sample comparison and longitudinal studies of tissue elasticity. We validate the technique using tissue-mimicking phantoms and demonstrate the ability to map elasticity of freshly excised malignant and benign human breast tissues.Kelsey M. Kennedy, Lixin Chin, Robert A. McLaughlin, Bruce Latham, Christobel M. Saunders, David D. Sampson and Brendan F. Kenned

    Hatchery Production of Shrimp Seeds

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    T he pioneering efforts of Hudinaga in the successful spawning of Penaeus japonicus under controlled conditions and their subsequent rearing upto the juvenile stage have paved way for the large scale hatchery production of seed of penaeid prawns for aquaculture. There are two basic hatchery techniques for mass rearing of larvae of penaeid prawns - Japanese techniques and Galveston technique. These techniques have been appropriately modified to suit different geographical and climatic conditions and different species of prawns used for aquaculture. Thus m any gradations between these two techniques have been noticed in different parts of the world. Som etim es combinations o f these two techniques have also been used

    Shrimps

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    Among edible crustaceans (shelled organism s) shrimp is considered as a highly valuable commodity. The great economic use of this resource for domestic and export purposes has led to over exploitation of most of the major shrimp stocks of the world. According to World Fishery Statistics, the global shrimp production, showing a rather slow annual growth rate of 4.5 to 10% during 1981-87 period, has been stagnating at about 2.5 million tonnes per year during 1988-90 period. The Indian ocean accounts for an average of about 3.6 lakh tonnes (17%) annually, of which nearly 65% com es from the Eastern region. While the fishery of this region showed an upward trend during the past few years mainly due to increased landings in Indonesia, Bangladesh and East coast of India, the fishery of Western Indian Ocean remained more or less steady at about 2.3 lakh tonnes. From the present level of shrimp production against the effort input it is universally believed that further increase in production of this resource from the conventional shrimp grounds is not possible to any appreciable extent. This being the case, development of deep-sea shrimping and aquaculture of shrimp has been given considerable stress as alternate means of augmenting production through out the world
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