556 research outputs found

    Spurious signals in DQF spectroscopy: two-shot stimulated echoes

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    The most widely used technique for double-quantum filtered (DQF) single-voxel spectroscopy (SVS) is based on a symmetric PRESS sequence with two additional spatially unselective π/2 pulses, one of which is usually frequency selective. The actual filtering, rejecting signals from all uncoupled resonances, can be done by suitable phase cycling of the rf pulses in successive shots, but in practice gradient filtering is always used. Under usual conditions the sequence repetition time is comparable to the spin-lattice relaxation time, and a stimulated echo is formed by five out of the ten rf pulses in two consecutive shots. This echo is not filtered out by the gradients, and additional phase cycling is needed to eliminate it. Its spatial origin is the full transverse slice selected by the last pulse of the PRESS sequence. The SVS shimming procedure may create an important field variation in this slice (outside the volume of interest VOI). Water singlet signals therefore appear in a band of frequencies other than 4.7 ppm, and remain unaffected by water suppression pulses. In practice phase-alternation schemes can reduce these spurious signals by several orders of magnitude, but even then they may mask the weak metabolite signals of interest. We describe a strategy to minimize these spurious signals and propose a 16-step phase cycling scheme that attenuates the stimulated echo in every two-step subcycl

    Dynamic Nuclear Polarization by Thermal Mixing Under Partial Saturation

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    We describe a low-temperature thermodynamic model for dynamic nuclear polarization (DNP) via continuous-wave partial saturation of electron spin resonance (ESR) lines that are both homogeneously and inhomogeneously broadened. It is a variant of a reasoning proposed by Borghini, which in turn used Redfield's thermodynamic treatment of saturation. Our variant is furthermore based on Provotorov's insight that under partial saturation of a coupled-spin system two distinct spin temperatures should appear in a thermodynamical theory. We apply our model to DNP results obtained at a temperature of 1.2K and in magnetic fields of 3.35 and 5T on 1-13C labeled sodium acetate dissolved in a frozen D2O/ethanol-d6 solution doped with the free radical TEMP

    Can we enhance the ability to return to work among workers with stress-related disorders?

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    <p>Abstract</p> <p>Background</p> <p>Stress-related disorders are widespread and responsible for high societal costs e.g. sick leave payment and reduced productivity. The aim of this study was to evaluate the effect of an intervention program on return to work or labour market.</p> <p>Methods</p> <p>In a controlled interventional study design we compared 72 emotionally distressed patients, who received support during 2006, with 89 control individuals who had also been sick listed for emotional distress. Intervention was provided by trained psychologists and social workers who were in continuous dialog with the patients, providing counselling e.g. on decisions concerning resumption of work, support to families, participation in meetings with the workplace. Basically, the controls and the intervention group share the same access to welfare benefits. The main outcome was time to return to labour market (TTR).</p> <p>Results</p> <p>The baseline characteristics were similar in the two groups. There were no differences in the rate of resuming work between the two groups. About 80% in both groups had returned to the labour market after one year.</p> <p>Conclusion</p> <p>An intervention program with psychological stress management and case management did not improve work capability compared to usual care. Work resumption as a single outcome probably is an insensitive parameter of intervention management quality, and should be supplemented by other data on different aspects of treatment.</p

    Exploring the return-to-work process for workers partially returned to work and partially on long-term sick leave due to common mental disorders:a qualitative study

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    Purpose. We conducted a qualitative study into the return-to-work process of workers partially on sick leave due to common mental disorders. Our objectives were to describe the barriers to a full return to work, solutions, communicating to the working environment and the aim of a full return to work, all as perceived by the workers. Method. Workers who had partially returned to work and were partially on long-term sick leave due to a stress-related, anxiety or depressive disorder were eligible for this study. Fourteen workers were interviewed and the interviews were transcribed verbatim and coded. Results. The perceived main barriers were: inability to set limits, recognise exhaustion and to control cognitions and behaviour such as perfectionism. A general pattern in the process was that all workers perceived barriers to a full return to work; most workers were able to mention solutions; all workers aimed for a full return to work, and after some time all workers were met with sufficient understanding and social support from their supervisor and health care professional. However, hardly any worker intended to implement or utilise the solutions at the workplace, except the structural adaptations of the work demands. Conclusions. The pattern we found suggests a critical intention-behaviour gap between solutions and intentions for a full return to work and its implementation at work. This implies that we should develop new interventions that focus on helping workers and their environment to bridge this gap

    Factors associated with first return to work and sick leave durations in workers with common mental disorders

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    Background: Associations are examined between socio-demographic, medical, work-related and organizational factors and the moment of first return to work (RTW) (within or after 6 weeks of sick leave) and total sick leave duration in sick leave spells due to common mental disorders. Methods: Data are derived from a Dutch database, build to provide reference data for sick leave duration for various medical conditions. The cases in this study were entered in 2004 and 2005 by specially trained occupational health physicians, based on the physician's assessment of medical and other factors. Odds ratios for first RTW and sick leave durations are calculated in logistic regression models. Results: Burnout, depression and anxiety disorder are associated with longer sick leave duration. Similar, but weaker associations were found for female sex, being a teacher, small company size and moderate or high psychosocial hazard. Distress is associated with shorter sick leave duration. Medical factors, psychosocial hazard and company size are also and analogously associated with first RTW. Part-time work is associated with delayed first RTW. The strength of the associations varies for various factors and for different sick leave durations. Conclusion: The medical diagnosis has a strong relation with the moment of first RTW and the duration of sick leave spells in mental disorders, but the influence of demographic and work-related factors should not be neglected

    Development and evaluation of a strength-based method to promote employment of work-disability benefit recipients with multiple problems:A feasibility study

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    Background For people with disabilities, chances to find or keep work are negatively affected by multiple problems like lower education, poverty and poor health. Furthermore, although active labour market policies proved to be effective for unemployed in general, success rates are poor for persons who are unemployed due to multiple problems. The present study aims to describe the development of a method as well as professional training to teach its application, and to assess the feasibility of method and training. The Strength-based method (CARm) aims to promote employment of work-disability benefit recipients with multiple problems. Methods The main principles of the Strength model were redesigned for better applicability in a population of work-disability beneficiaries, resulting in the CARm method. As part of the CARm method, a training module for Labour Experts (LEs) was developed. To assess the new designed method and training, a one-group, pre-post design was used. Data were collected from eight participating LEs, five female and 3 male, aged between 41and 55 years and having 2–17 years working experience. We used self-report questionnaires and a semi-structured discussion meeting after the training sessions with the LEs. Results Eight labour experts (LEs) from the Dutch Social Security Institute participated in the study. Most LEs felt an improvement in their ability to ascertain developmental needs, opportunities and threats in the client’s situation. Three months after the training, LEs almost unanimously agreed on the statements ‘I expect to use the CARm method more frequently in the future’ and ‘I use the CARm method in daily practice whenever possible’. The overall rating for the training on a scale from 1 to 10 was 7.6 (range 7–9). The overall satisfaction with the trainers was good. Conclusions The CARm method and training was found to be a feasible approach to facilitate LEs working at the UWV reintegration service to support clients with multiple problems. Sufficient managerial support for participating LEs is a key factor for successful implementation of CARm. Results show that CARm is worth testing for efficacy in a future trial

    EPR study of vanadium (4+) in the anatase and rutile phases of TiO2

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    We present cw and pulsed EPR experiments on V4+ in the rutile and anatase phases of TiO2. For the rutile phase, the cw data confirm earlier results, but the relaxation data are different from those previously reported. No earlier results for V4+ in the unreduced pure anatase phase exist. We show that a simple point-charge model can be used to interpret the values of the g tensors, but that models considering only nearest neighbors will give erroneous results. We conclude that the observed V4+ is substitutional in the rutile, but interstitial in the anatase phase. We propose a relaxation mechanism through phonon-modulated hyperfine coupling to explain our T1 data in the rutile phase

    A capability perspective on sustainable employability:A Dutch focus group study on organizational, work and personal conversion factors

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    Objective In the field of work, there is a shift towards more value-based approaches to study the sustainable employability of the present-day worker. The capability approach offers a value based and innovative conceptualisation and framework of sustainable employability characterized by contextuality, normativity and diversity. The capabilities of Dutch employees have been established and validated, yet it is not known which conversion factors on a personal, work and organizational level enable employees to achieve value in work in different Dutch occupational sectors. Methods Our qualitative approach included seven focus groups in different occupational sectors including elderly care, higher education, insurance work, facility management and the oil-, car- and chemical industry. Each focus group included 5–11 participants and took approximately one and a half hour. A qualitative content analysis was used to analyse the data, by combining deductive and inductive coding respectively. Deductive coding involved assigning themes to the conversion of resources into capabilities at the organizational, work and personal level. Results On the organizational conversion level, important themes were cultural aspects, power relations, shortage of personnel and policies for self-management. On the work conversion level, social contacts, communication and workload, tasks and schedules were identified. Social contacts were described as a work value in itself, but also conditional for achieving other work values. On the personal conversion level, experienced work stress, motivation and the ability to achieve values informally within the company. Conclusion From our findings it follows that focus groups are sensitive to identify conversion factors on all three levels of conversion. In addition, companies and their employees might effectively increase work capabilities by being sensitive to all three conversion levels simultaneously. Further research is necessary to study the effect of a capability-based intervention at the work floor
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