99 research outputs found

    Influence of static Jahn-Teller distortion on the magnetic excitation spectrum of PrO2: A synchrotron x-ray and neutron inelastic scattering study

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    A synchrotron x-ray diffraction study of the crystallographic structure of PrO2 in the Jahn-Teller distorted phase is reported. The distortion of the oxygen sublattice, which was previously ambiguous, is shown to be a chiral structure in which neighbouring oxygen chains have opposite chiralities. A temperature dependent study of the magnetic excitation spectrum, probed by neutron inelastic scattering, is also reported. Changes in the energies and relative intensities of the crystal field transitions provide an insight into the interplay between the static and dynamic Jahn-Teller effects.Comment: 7 pages, 6 figure

    Magnetic and Metal-Insulator Transitions in beta-Na0.5CoO2 and gamma-K0.5CoO2 -NMR and Neutron Diffraction Studies-

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    Co-oxides beta-Na0.5CoO2 and gamma-K0.5CoO2 have been prepared by the Na de-intercalation from alpha-NaCoO2 and by the floating-zone method, respectively. It has been found that successive phase transitions take place at temperatures Tc1 and Tc2 in both systems. The appearance of the internal magnetic field at Tc1 with decreasing temperature T indicates that the antiferromagnetic order exists at T < Tc1, as in gamma-Na0.5CoO2. For beta-Na0.5CoO2, the transition temperatures and the NMR parameters determined from the data taken for magnetically ordered state are similar to those of gamma-Na0.5CoO2, indicating that the difference of the stacking ways of the CoO2 layers between these systems do not significantly affect their physical properties. For gamma-K0.5CoO2, the quantitative difference of the physical quantities are found from those of beta- and gamma-Na0.5CoO2. The difference between the values of Tci (i = 1 and 2) of these systems might be explained by considering the distance between CoO2 layers.Comment: 8 pages, 14 figures, 1 Tabl

    Investigation of the Spin Density Wave in NaxCoO2

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    Magnetic susceptibility, transport and heat capacity measurements of single crystal NaxCoO2 (x=0.71) are reported. A transition to a spin density wave (SDW) state at Tmag = 22 K is observable in all measurements, except chi(ac) data in which a cusp is observed at 4 K and attributed to a low temperature glassy phase. M(H) loops are hysteretic below 15 K. Both the SDW transition and low temperature hysteresis are only visible along the c-axis. The system also exhibits a substantial (~40%) positive magnetoresistance below this temperature. Calculations of the electronic heat capacity gamma above and below Tmag and the size of the jump in C indicate that the onset of the SDW brings about the opening of gap and the removal of part of the Fermi surface. Reduced in-plane electron-electron scattering counteracts the loss of carriers below the transition and as a result we see a net reduction in resistivity below Tmag. Sodium ordering transitions at higher temperatures are observable as peaks in the heat capacity with a corresponding increase in resistivity.Comment: 14 pages, 6 figure

    "I try and smile, I try and be cheery, I try not to be pushy. I try to say ‘I’m here for help’ but I leave feeling… worried’’: A qualitative study of perceptions of interactions with health professionals by community-based older adults with chronic pain

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    Background: Over 50% of community-dwelling older adults experience chronic pain, which threatens their quality of life. Of importance to their pain management is older people’s interaction with health professionals that, if unsatisfactory, may impair the outcome. Aims: To add to the limited research specific to older people living with chronic pain in the community, we explored how they perceive their experiences of interacting with health professionals, seeking factors that might optimise these interactions. Methods: Purposive sampling was used to recruit men and women .65 years with self-reported musculoskeletal chronic pain. Qualitative individual interviews and one group interview were undertaken with 23 participants. Data were transcribed verbatim and underwent Framework Analysis. Results: Three themes were identified. Seeking help illustrates issues around why older people in the community may or may not seek help for chronic pain, and highlights the potential involvement of social comparison. Importance of diagnosis illustrates the desire for professional validation of their condition and an aversion to vague explanations based on the person’s age. Being listened to and being heard illustrates the importance of empathic communication and understanding expectations, with due respect for the person’s age. Conclusions: In common with people of all ages, an effective partnership between an older person in pain and health professionals is essential if pain is to be reported, appropriately assessed and managed, because of the subjective nature of pain and its treatment responses. For older people with pain, perception about their age, by both parties in the partnership, is an additional factor that can unnecessarily interfere with the effectiveness of this partnership. Health professionals should engage with older adults to clarify their expectations about pain and its management, which may be influenced by perceptions about age; and to encourage expression of their concerns, which may also be affected by perceptions about age

    Upper limb neuropathy in computer operators? A clinical case study of 21 patients

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    BACKGROUND: The character of upper limb disorder in computer operators remains obscure and their treatment and prevention have had limited success. Symptoms tend to be mostly perceived as relating to pathology in muscles, tendons or insertions. However, the conception of a neuropathic disorder would be supported by objective findings reflecting the common complaints of pain, subjective weakness, and numbness/tingling. By examining characteristics in terms of symptoms, signs, and course, this study aimed at forming a hypothesis concerning the nature and consequences of the disorder. METHODS: I have studied a consecutive series of 21 heavily exposed and severely handicapped computer-aided designers. Their history was recorded and questionnaire information was collected, encompassing their status 1/2 – 1 1/2 years after the initial clinical contact. The physical examination included an assessment of the following items: Isometric strength in ten upper limb muscles; sensibility in five homonymously innervated territories; and the presence of abnormal tenderness along nerve trunks at 14 locations. RESULTS: Rather uniform physical findings in all patients suggested a brachial plexus neuropathy combined with median and posterior interosseous neuropathy at elbow level. In spite of reduced symptoms at follow-up, the prognosis was serious in terms of work-status and persisting pain. CONCLUSIONS: This small-scale study of a clinical case series suggests the association of symptoms to focal neuropathy with specific locations. The inclusion of a detailed neurological examination would appear to be advantageous with upper limb symptoms in computer operators

    National plans and awareness campaigns as priorities for achieving global brain health

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    Neurological conditions are the leading cause of death and disability combined. This public health crisis has become a global priority with the introduction of WHO's Intersectoral Global Action Plan on Epilepsy and Other Neurological Disorders 2022–2031 (IGAP). 18 months after this plan was adopted, global neurology stakeholders, including representatives of the OneNeurology Partnership (a consortium uniting global neurology organisations), take stock and advocate for urgent acceleration of IGAP implementation. Drawing on lessons from relevant global health contexts, this Health Policy identifies two priority IGAP targets to expedite national delivery of the entire 10-year plan: namely, to update national policies and plans, and to create awareness campaigns and advocacy programmes for neurological conditions and brain health. To ensure rapid attainment of the identified priority targets, six strategic drivers are proposed: universal community awareness, integrated neurology approaches, intersectoral governance, regionally coordinated IGAP domestication, lived experience-informed policy making, and neurological mainstreaming (advocating to embed brain health into broader policy agendas). Contextualised with globally emerging IGAP-directed efforts and key considerations for intersectoral policy design, this novel framework provides actionable recommendations for policy makers and IGAP implementation partners. Timely, synergistic pursuit of the six drivers might aid WHO member states in cultivating public awareness and policy structures required for successful intersectoral roll-out of IGAP by 2031, paving the way towards brain health for all.</p

    Exploring Doctor–Patient Communication in Immigrant Australians with Type 2 Diabetes: A Qualitative Study

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    OBJECTIVE: The study explored the perceptions of Australian immigrants about their interactions with doctors regarding the diagnosis, treatment, and management of type 2 diabetes mellitus. RESEARCH DESIGN AND METHODS: In-depth interviews were conducted with 30 men and women from Greek, Indian, Chinese, and Pacific Island backgrounds living in Melbourne, Australia, to elicit their perceptions of the management of diabetes and its impact. Participants were recruited through a convenience sample of general practitioners and community organizations providing support to people living with diabetes. Topics discussed included initial reaction to diagnosis, patient—health care provider communication, and the influence of message framing on the perception of the quality of the doctor–patient relationship. Transcripts were coded and analyzed by both authors. RESULTS: Numerous issues facilitate or inhibit constructive and positive relationships between doctors and patients with type 2 diabetes. Patients reported difficulty in absorbing all the information provided to them at early consultations, and experienced difficulty comprehending the practical aspects of management. Styles of communication and discourses of normalization and catastrophe influenced participants’ responses. CONCLUSION: Doctors face a complex task in encouraging behavioral change and adherence and establishing and maintaining a supportive relationship with patients. The timing and technical complexity of communication about diabetes, its management, and the prevention of complications require further attention

    A descriptive study of older adults with persistent pain: Use and perceived effectiveness of pain management strategies [ISRCTN11899548]

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    BACKGROUND: Persistent pain is a common, often debilitating, problem in older adults; however, few studies have focused on the experiences of older adults in managing their pain. The objective of this study was to describe the use and perceived effectiveness of pain management strategies in a sample of older adults and to explore the associations of these variables with demographic and psychosocial characteristics. METHODS: Adults ≥ 65 years old and living in retirement facilities who reported persistent pain (N = 235, mean age = 82 years, 84% female, 94% white) completed measures of demographics, pain, depression, self-efficacy for managing pain, and a Pain Management Strategies Survey. Participants identified current and previous-year use of 42 pain management strategies and rated helpfulness of each on a 5-point scale. RESULTS: Acetaminophen, regular exercise, prayer, and heat and cold were the most frequently used pain management strategies (61%, 58%, 53%, and 48%, respectively). Strategies used by >25% of the sample that were rated moderately or more helpful (i.e., >2 on a 0 to 4 scale) were prayer [mean (SD) = 2.9 (0.9)], opioids [2.6 (0.8)], regular exercise [2.5 (1.0)], heat/cold [2.5 (1.0)], nonsteroidal anti-inflammatory drugs [2.4 (1.0)], and acetaminophen [2.3 (1.0)]. Young-old (65–74 years) study participants reported use of more strategies than did old-old (85+ years) participants (p = .03). Perceived helpfulness of strategy use was significantly associated with pain intensity (r = -.14, p < .0001), self-efficacy (r = .28, p < .0001), and depression (r = -.20, p = .003). CONCLUSION: On average, older adults view the strategies they use for persistent pain as only moderately helpful. The associations between perceived helpfulness and self-efficacy and depression suggest avenues of pain management that are focused less on specific treatments and more on how persons with persistent pain think about their pain

    59Co, 23Na, and 1H NMR Studies of Double-Layer Hydrated Superconductors NaxCoO2-yH2O

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    We present our NMR studies of double-layer hydrated cobalt oxides NaxCoO2-yH2O (x ~ 0.35, y ~ 1.3) with various Tc = 0 - 4.8 K and magnetic transition temperatures. High-resolution 1^{1}H NMR spectrum served as an evidence for the existence of H3_{3}O+^{+} oxonium ions. 23^{23}Na nuclear spin-lattice relaxation rates served to detect local field fluctuations sensitive to Tc. 59^{59}Co nuclear quadrupole resonance (NQR) spectra served to classify the various Tc samples. From the classification by 59^{59}Co NQR frequency, the double-layer hydrated compounds were found to have two superconducting phases closely located to a magnetic phase. In the normal state and at a magnetic field in the abab-plane, two 59^{59}Co NMR signals with different Knight shifts and different 59^{59}Co nuclear spin-lattice relaxation times 59T1^{59}T_{1} were observed. The two 59^{59}Co NMR signals suggest magnetic disproportionation of two Co sites or in-plane (XY) anisotropy of a single Co site. Non Korringa behavior and power law behavior in zero-field NQR 1/59T1^{59}T_{1} above and below Tc suggest non-Fermi liquid and unconventional superconductivity.Comment: 12 pages, 7 figures, Submitted to DPG spring meeting at Regensburg, March 200

    A cross-sectional study of the relation between symptoms and physical findings in computer operators

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    BACKGROUND: The character of upper limb disorder in computer operators is subject to debate. A peripheral nerve-involvement is suggested from the common presence of a triad of symptoms consisting of pain, paraestesiae and subjective weakness, and from physical findings suggesting neuropathy. This study aimed to examine the outcome of a detailed neurological examination in computer operators and to compare findings with the presence of symptoms. METHODS: 96 graphical computer operators answered a modified Nordic Questionnaire including information on perceived pain in the shoulder, elbow, and wrist/hand scored for each region on a VAS-scale 0 – 9. In addition, they underwent a physical examination including the subjective assessment of the individual function of 11 upper limb muscles, of algesia in five and vibratory threshold in three territories, respectively, and of mechanosensitivity of nerves at seven locations. In order to reflect an involvement of the brachial plexus (chord level), the posterior interosseous nerve and the median nerve at elbow level we defined three patterns of neurological findings illustrating the course of nerves and their innervation. The pain scores summarized for the three upper limb regions (min. = 0, max = 27) in the mouse-operating and contralateral limbs were compared by a Wilcoxon test and the relation to each physical item analyzed by Kendall's rank correlation. The relation of summarized pain to each pattern was studied by application of a test of the trend across ordered groups (patterns). RESULTS: Pain, paraestesiae and subjective weakness was reported for 67, 23, and 7 mouse-operating limbs, respectively, with the summarized pain scores exceeding 4 in 33 limbs. Abnormal physical findings were prevalent. The summarized pain was significantly related to a reduced function in five muscles, to mechanical allodynia at one location and to elevated threshold to vibration in two territories. Brachial plexopathy was diagnosed in 9/2, median neuropathy in 13/5 and posterior interosseous neuropathy in 13/8 mouse operating/contralateral limbs, respectively. The summarized pain was significantly higher in the mouse-operating limbs and in limbs with any of the defined patterns. There was a significant trend between the summarized pain and the summarized scores for the items contained in each pattern. CONCLUSION: This small-scale study of a group of computer-operators currently in work and with no or minor upper limb symptoms has indicated in symptomatic subjects the presence of peripheral nerve-afflictions with specific locations
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