Comparing wire-mesh sensor with neutron radiography for measurement of liquid fraction in foam

The liquid fraction of foam is an important quantity in engineering process control and essential to interpret foam rheology. Established measurement tools for the liquid fraction of foam, such as optical measurement or radiography techniques as well as weighing the foam, are mostly laboratory-based, whereas conductivity-based measurements are limited to the global measurement without detailed spatial information of liquid fraction. In this work, which combines both types of measurement techniques, the conductivity-based wire-mesh sensor is compared with neutron radiography. We found a linear dependency between the liquid fraction of the foam and the wire-mesh readings with a statistical deviation less than 15%. However, the wire-mesh sensor systematically overestimates the liquid fraction, which we attribute to liquid bridge formation between the wires.

Oscillatory surface deformation of paramagnetic rare-earth solutions driven by an inhomogeneous magnetic field

The deformation of the free surface of a paramagnetic liquid subjected to a nonuniform magnetic field is studied. A transient deformation of the surface caused by the interplay of gravity, magnetic field, and surface tension is observed when a permanent magnet is moved vertically downward to the free surface of the liquid. Different concentrations of rare-earth-metal salt (DyCl_{3}) are used and different magnet velocities are studied. The deformation of the interface is followed optically by means of a microscope and recorded with a high-speed camera. The experimental results are compared and discussed with complementary numerical simulations. Detailed results are given for the static shape of the deformed surface and the temporal evolution of the surface deformation below the center of the magnet. The frequency of the surface oscillations is found to depend on the concentration of the salt and is compared with analytical findings. Finally, a potential application of the effects observed is presented.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Self-Pinning on a Liquid Surface

We report on the first experimental evidence of a self-pinning liquid drop on a liquid surface. This particular regime is observed for a miscible heavier oil drop (dichloromethane) deposited on an aqueous solution laden by an ionic surfactant (hexadecyltrimethylammonium bromide). Experimental characterization of the drop shape evolution coupled to particle image velocimetry points to the correlation between the drop profile and the accompanying flow field. A simple model shows that the observed pinned stage is the result of a subtle competition between oil dissolution and surfactant adsorption.

Dendrite fragmentation in alloy solidification due to sidearm pinch-off

Dendrite sidebranch detachment is an important fragmentation mechanism during the solidification of alloys. The detachment occurs at the junction between a sidearm and its parent stem. While this pinching process is driven by capillarity, the presence of solidification opposes the instability. Using a simple numerical model of a single sidearm, we are able to capture the essential dynamics of dendrite sidebranch development and the resulting morphological transitions. While shortly before pinch-off the neck itself obeys well-known universal scaling relations, the overall evolution of the sidearm shape sensitively depends on its initial geometry and the rate of solidification. It is found that pinch-off only occurs over limited ranges of geometrical parameters and cooling rates and is generally bounded by sidearm retraction and coalescence regimes. Simple scaling relations are identified that provide the bounds for the pinch-off regime. Pinching at the branching point is shown to be faster than the Rayleigh-Plateau instability of an infinitely long cylinder.

[Diagnostically Approach to Pediatric Carpal Fractures: a Retrospective Analysis]

INTRODUCTION

Carpal fractures in children are rare, but can be missed, as their clinical symptoms are unspecific and discrete. Even X-ray diagnosis is difficult. Timely diagnosis and consistent therapy are especially important for scaphoid fractures, as they can help to avoid complications such as non-union or avascular necrosis. A diagnostic approach to paediatric carpal fractures will be discussed on the basis of the following group of patients.

METHODS

Retrospective analysis of children under 14 years treated in our institution between 09/2010 and 02/2012 for clinically suspected carpal fracture. In the primary evaluation, all children underwent standard X-rays of the hand and/or wrist. All patients were treated by cast immobilisation until complete clinical recovery. All patients with clinical signs of carpal fracture were treated by cast immobilization, even with normal X-rays. The clinical follow-up examination was after 10 to 14 days. In patients with persistent complaints, MRI was performed. We retrospectively evaluated the records of all patients: the fractured carpal bone, and X-ray and MRI-diagnosis were stated. We calculated the mean difference between first presentation and MRI and the mean period for total recovery, in patients with fracture or non-fracture.

RESULTS

61 children (27 boys and 34 girls, mean age 11.5 y) were included in our study. The mean delay between accident and time of first presentation to our paediatric ED was 0.6 days. In primary X-rays, a carpal fracture was demonstrated in only in 2 (3.3 %) patients, but was suspected in only 6 (9.8 %) of patients. In 53 (87.9 %) patients, there was no radiographic evidence of carpal fracture. 14 patients underwent additional scaphoid views, but scaphoid fracture was confirmed in only 1 (7 %) of these patients. In 3 (21.4 %) patients, a scaphoid fracture was suspected and in 10 patients a carpal fracture could be excluded. After a mean time of 11.8 days, all patients underwent a clinical follow-up examination. 32 (54 %) patients had persistent symptoms and MRI was done after a mean time of 17 days. Carpal fracture was then excluded in 12/32 (37 %) patients and was diagnosed in another 20/32 (63 %) children. There were 14 scaphoid fractures, including 3× bone bruise lesions, 4 capitate fractures, 3 triquetral fractures, including 1× bone bruise lesion and 1 bone bruise lesion of the trapezoid. In patients with proven carpal fracture, it took a mean time of 56 days for complete recovery, in comparison with 15 days in patients with excluded carpal fracture. Surgical therapy was unnecessary in any of the patients, and there were no complications.

CONCLUSION

In children with clinical and radiographic carpal fracture, diagnosis is difficult and often unsuccessful at first. Even in discrete clinical complaints, generous cast immobilization is essential and clinical follow up is recommended not later then 14 days. In patients with persistent clinical symptoms, MRI is the imaging method of choice, as it is capable of detecting carpal fractures and even bone bruise lesions with high sensitivity, thereby avoiding unnecessary diagnostic or therapeutic stress for the patients.

[Effects of Behaviour-oriented Exercise Interventions as Supplement within Structured Health-care Programmes for Diabetes Mellitus Type 2 - A Quasi-experimental Multicentre Intervention Study]

Exercise programs do not belong to standard treatment within disease management programmes for diabetes mellitus type 2, up to now. For these reason the effects of a 10-week behaviour-oriented exercise programme have been evaluated focusing on change in activity behaviour and health-related qualitiy of life. 202 patients took part in the investigation. There were significant inbetween group differences in some aspects of the outcome parameters. The study presents useful information on how to modify existing DMPs successfully for improving patient treatment.

[Complete rupture of the peroneal nerve by knee distortion]

This report describes a case of complete rupture of the peroneal nerve as a consequence of low velocity trauma. A 54-year-old physically fit patient suffered a complex trauma with complete nerve discontinuity as a result of knee joint distortion without external force. The initial medical findings were unremarkable, in particular neither the accident medical history nor the initial sensitivity impairment suggested the presence of serious knee damage; however, during clinical diagnostics a complex trauma with rupture of the peroneal nerve was found. Accordingly, an extensive revision with nerve suturing was carried out.

[Comparison of stability of plate fixateurs with parallel and oblique screw directions]

INTRODUCTION

One of the main failure mechanisms of modern plate fixateurs is the tearing of the whole plate-screw construct out of the osteoporotic bone. The aim of this study was to show whether an oblique screw placement can improve the fixation of the plate to the bone.

METHODS

A steel probe was fixed to a synthetic bone (Fa. Sawbones) with standard titanium fixed-angle screws in parallel and 55° oblique positioning. We tested the static tear force and the dynamic stability (force distance 1.4 or 1.6 mm, 610 and 900 N, frequency of force shift of 560 or 380/min). Endpoint was a visible tear of the artificial bone. In addition we performed a morphological analysis of the torn fragments.

RESULTS

The maximal tear force was 2.04 kN (1.95-2.13) for oblique and 2.66 kN (2.55-2.77) for parallel placement (p < 0.05). With a parallel positioning a higher number of force shifts were performed before a visual tear appeared. With parallel positioning the screw canal was torn with an intact surrounding corticalis; in oblique positioning the threads remained intact, the corticalis was torn out with a wedge.

DISCUSSION

An oblique screw positioning does not result in a higher tear force in modern plate fixateurs.

[Taking the anamnesis with a questionnaire - safe and effective]

INTRODUCTION

The anamnesis is essential for the treatment of any patient. On the other hand, the data are often of poor quality. The aim of the study was to work out whether a questionnaire which is filled out by the patient him-/herself is a reasonable tool for data acquisition.

METHODS

In a level-IV trauma centre the data acquisition of 50 consecutive patients was performed with a questionnaire which was checked by a doctor. Excluding criteria were an age < 18 years, previous treatment in the clinic, a transfer from an external clinic or a caring institution and a dementia. The results were compared with the data of the 50 patients prior to the study start.

RESULTS

We collected data about the general doctor, diseases, allergies, tobacco usage, drugs, operations and the familial situation. In all 7 fields the questionnaire raised more data than the oral survey; in 4 sections the difference was significant, in 3 (p > 0.05).

DISCUSSION

A questionnaire is a reasonable, time-sparing tool for data acquisition of the individual anamnesis in a surgical clinic.

[Sonographic fracture diagnosis in children]

X-rays are the standard imaging procedure for the diagnosis of pediatric long bone fractures. Recent studies show that ultrasound (US) imaging is also qualified to diagnose pediatric long bones fractures. Thus, the diagnosis and decision-making for the treatment of metaphyseal forearm fractures in children can be performed by solely using US. The sonographic fat pad sign has been proven to be a useful primary screening tool for pediatric elbow injuries. If there is a negative fat pad sign, a fracture is unlikely and taking additional radiographs is dispensable at this time. If there is a positive fat pad sign, a fracture is likely and radiographs should be taken. US is also useful to exclude subcapital humeral fractures and to estimate fracture displacement. If a fracture of the subcapital humerus is present, additional radiographs are necessary to avoid overlooking of pathologic fractures. For reliable sonographic fracture diagnosis in childhood, a detailed history und exact clinical examination are required.

[Uncertainty in the radiological evaluation of deformity in proximal humerus fractures]

INTRODUCTION

The accurate measurement of the deformity of proximal humerus fractures is essential for a proper treatment, particularly in the growing bone. Due to the local pain the correct projection in standard X-rays is difficult to achieve and, in contrast to other joints, cannot be verified in the X-ray. Even with the correct projections a mismeasurement can occur when the rotation is 45° to both planes. The aim of this study was to objectify the error sources and reveal starting points for an improvement.

MATERIAL AND METHODS

In a three-step study we initially developed a mathemathical formula in cooperation with the faculty of mathematics of the University of Duisburg-Essen. This formula was proved with X-ray imaging of a steel rod which was bent 120°, simulating a 60° deformity. X-ray images with different rotation and tilt were taken and compared with the values calculated with the above-mentioned formula. In the third step X-rays of a healthy shoulder in different rotation and tilt positions were presented to 2 orthopaedic and 3 radiological consultants. The aim was to determine the direction and amount of rotation and tilt.

RESULTS

The first theoretical step resulted in a mathematical formula which describes the optical deformation based on real deformation, tilt and rotation. The evaluation showed a mean difference of 0.5° (0-1.2°) between the calculated and the measured values. In the third step, evaluation of the X-rays of a shoulder showed that two in 50 (4 %) of the values were correct, in additional 28 cases (56 %) the tendency of the direction of the rotation was correct, the extent of the rotation was missed by 19.6° (0-60°). Ante- and retroversion were evaluated correctly in nine cases (18 %), the extent was missed by a mean of 23° (0-50°). In seven cases (18 %) the tendency for rotation and ante-/retroversion was correct, in 11 cases (22 %) one or both aspects could not be evaluated, in additional 8 cases (16 %) the extent could not be estimated.

DISCUSSION

Our results show that rotation and tilt of the proximal humerus cannot be estimated in shoulder X-rays and therefore a reliable measurement of the deformity of proximal humerus fractures is extremely unsafe. This problem is relevant for clinical practice because of the high likeliness of unaccurate projections in shoulder X-ray imaging after trauma. Especially for the growing bone the problem is evident, so that new ways of determining the deformity are mandatory.

[Ultrasound-based treatment of proximal humerus fractures in children]

INTRODUCTION

The treatment of juvenile proximal humerus fractures is based on the extent of the deformity. The standard diagnosis with X-ray images in 2 directions is error-prone and can lead to a suboptimal treatment. The aim of this study was to evaluate if ultrasound imaging can improve the measurement of the deformity of proximal humerus fractures.

MATERIAL AND METHODS

In a prospective, multicentre trial children aged 0-12 years with a suspected proximal humerus fracture were initially examined with a 10-MHz linear transducer in 4 directions and the maximum deformity was determined. Afterwards the standard X-rays were taken and the results of both methods compared. The certainty of both methods was compared with a standardised nominal scale.

RESULTS

From 8/2010 to 5/2011 6 consultants in 4 hospitals examined 30 patients (16 m, 14 f, mean age 7.9 years). In 15 cases the ultrasound showed a larger deformation than the X-rays and in 2 cases vice versa. In 11 cases the measurement was identical 6 of which were undisplaced. The mean difference of the measurement of the deformity was + 8.6°, with 14.2° in the displaced fractures. The certainty of the ultrasound was rated significantly higher (p < 0.05) than that of radiography.

DISCUSSION

With a correct technique the deformity cannot be overestimated by ultrasound means and the safeness is rated significantly higher in comparison to the X-ray imaging. It seems that ultrasound is a meaningful method to improve the measurement of the deformity of proximal humerus fractures in children. Deficiencies are found only in cases with massive deformities which demand a reduction and stabilisation.

Bromelain proteinases modulate the cd44 expression on human molt-4/8 leukemia and sk-mel-28 melanoma-cells in-vitro

CD44 cell surface proteins are involved in leukocyte binding to endothelium and the metastatic spread of tumor cells. Using flow cytometric analysis (FCMA), we investigated the effects of the proteases bromelain, papain, trypsin, and chymotrypsin on the density of CD44 molecules present on human leukemia Molt 4/8 cells. Bromelain was found to be most active in reducing CD44 receptor density. In addition, the effects of the purified bromelain proteinases F4 and F9 were investigated. On Molt 4/8 cells crude bromelain and F9, with the highest proteolytical activity, were found to be most active in reducing CD44 receptor density with a half maximal value of 1.9 mu g/ml and 2.3 mu g/ml, respectively. On human SK-Mel 28 melanoma cells especially F9 showed a strong effect, with a half maximal value of 1.5 mu g/ml. The implications of the findings are discussed with view of the reported antimetastatic activity of orally administrated bromelain with respect to CD44.

Bromelain proteases suppress growth, invasion and lung metastasis of B16F10 mouse melanoma cells

The thiolprotease bromelain, isolated from pine apple stem, was suggested for use in adjuvant tumor therapy. This study examined the in vitro effects of crude bromelain, bromelain F9 and papain on B16F10 mouse melanoma cell lung colonization, in vitro cell proliferation, invasion through matrigel and CD44 expression. In vitro treatment of the melanoma cells with bromelain F9 and papain before i.v. injection into mice prevented lung colonization. The lung weight at day 20 was significantly reduced from 5.1% (untreated cells) to 1.6% (bromelain F9 treated cells). Papain was as effective as bromelain F9. However, there was no difference in the lung weight between bromelain F9 treated and the untreated group at day 27. Protease removal and further incubation of the B16F10 cells retained their capacity to induce lung tumor metastases. The proteases inhibited growth of the melanoma cells in a dose dependent manner. Crude bromelain was most active with a half maximal value of 7.5 mu g/ml. However, the antiproliferative effects did not correlate with the proteolytic activity. In a matrigel invasion assay, the proteases reduced the invasive capacity of the melanoma cells maximally by about 30%. Using flow cytometry, the proteases were found to reduce the CD44 density, present on the melanoma cells, to a different degree: crude bromelain was more active than bromelain F9 and papain, which had higher proteolytic activity. Crude bromelain was most active in abolishing the CD44 re-expression after protease treatment.

Introduction to the focus issue: chemo-hydrodynamic patterns and instabilities

Pattern forming instabilities are often encountered in a wide variety of natural phenomena and technological applications, from self-organization in biological and chemical systems to oceanic or atmospheric circulation and heat and mass transport processes in engineering systems. Spatio-temporal structures are ubiquitous in hydrodynamics where numerous different convective instabilities generate pattern formation and complex spatiotemporal dynamics, which have been much studied both theoretically and experimentally. In parallel, reaction-diffusion processes provide another large family of pattern forming instabilities and spatio-temporal structures which have been analyzed for several decades. At the intersection of these two fields, "chemo-hydrodynamic patterns and instabilities" resulting from the coupling of hydrodynamic and reaction-diffusion processes have been less studied. The exploration of the new instability and symmetry-breaking scenarios emerging from the interplay between chemical reactions, diffusion and convective motions is a burgeoning field in which numerous exciting problems have emerged during the last few years. These problems range from fingering instabilities of chemical fronts and reactive fluid-fluid interfaces to the dynamics of reaction-diffusion systems in the presence of chaotic mixing. The questions to be addressed are at the interface of hydrodynamics, chemistry, engineering or environmental sciences to name a few and, as a consequence, they have started to draw the attention of several communities including both the nonlinear chemical dynamics and hydrodynamics communities. The collection of papers gathered in this Focus Issue sheds new light on a wide range of phenomena in the general area of chemo-hydrodynamic patterns and instabilities. It also serves as an overview of the current research and state-of-the-art in the field.

Chemo-Marangoni convection driven by an interfacial reaction: pattern formation and kinetics

A combined study devoted to chemo-Marangoni convection and the underlying kinetics is presented for a biphasic system in which surfactants are produced in situ by an interfacial reaction. The pattern formation studied in a Hele-Shaw cell in both microgravity and terrestrial environments initially shows an ensemble of chemo-Marangoni cells along a nearly planar interface. Soon, a crossover occurs to periodic large-scale interfacial deformations which coexist with the Marangoni cells. This crossover can be correlated with the autocatalytic nature of the interfacial reaction identified in the kinetic studies. The drastic increase in the product concentration is associated with an enhanced aggregate-assisted transfer after the critical micellar concentration is approached. In this context, it was possible to conclusively explain the changes in the periodicity of the interfacial deformations depending on the reactant concentration ratio.

[Ultrasound as a viable alternative to standard X-rays for the diagnosis of distal forearm fractures in children]

AIM

Distal forearm fractures are very common in childhood. Radiography of the wrist is the standard diagnostic procedure. But because of higher sensitivity of growing bones to ionising radiation the diagnostic use of X-rays should be minimised as much as possible. Recent studies have shown that distal forearm fractures in children can be safely and reliably diagnosed using only ultrasound. The aim of our study was to evaluate and confirm the safety and applicability of the ultrasound diagnostic procedure in comparison to X-ray diagnosis under routine conditions of our paediatric emergency department.

PATIENTS AND METHODS

We investigated 115 patients aged 2-14 years. After clinical assessment patients with suspected forearm fractures first underwent ultrasound examination of the metaphyseal forearm followed by standard two view radiographs of the wrist. Ultrasound and radiographic findings were then compared and sensitivity and specificity for ultrasound were calculated. In 9 patients with suspected displacements, sonographic and radiographic axis measurement were done and also compared.

RESULTS

Radiologically we found 62 patients with 78 distal forearm fractures. By ultrasound we also diagnosed 52 fractures. All patients with no fractures were correctly diagnosed as well. Referring to X-rays we calculated for ultrasound a sensitivity of 94.9 %, a specificity of 98 %, a negative predictive value of 97.4 % and a positive predictive value of 96.1 %. The mean difference of the deformities of the radius in the sagittal section measured sonographically and radiologically were 1.7° (SD 1.6°).

CONCLUSION

We confirm ultrasound is an applicable, rapid and safe alternative to X-rays in diagnosing metaphyseal forearm fractures in children. Even sonographic axis measurement seems to be a viable method. Thereby ultrasound potentially reduces the X-ray burden in children and additionally accelerates the diagnostic procedure.

Teratoma formation of human embryonic stem cells in three-dimensional perfusion culture bioreactors

Teratoma formation in mice is today the most stringent test for pluripotency that is available for human pluripotent cells, as chimera formation and tetraploid complementation cannot be performed with human cells. The teratoma assay could also be applied for assessing the safety of human pluripotent cell-derived cell populations intended for therapeutic applications. In our study we examined the spontaneous differentiation behaviour of human embryonic stem cells (hESCs) in a perfused 3D multi-compartment bioreactor system and compared it with differentiation of hESCs and human induced pluripotent cells (hiPSCs) cultured in vitro as embryoid bodies and in vivo in an experimental mouse model of teratoma formation. Results from biochemical, histological/immunohistological and ultrastuctural analyses revealed that hESCs cultured in bioreactors formed tissue-like structures containing derivatives of all three germ layers. Comparison with embryoid bodies and the teratomas revealed a high degree of similarity of the tissues formed in the bioreactor to these in the teratomas at the histological as well as transcriptional level, as detected by comparative whole-genome RNA expression profiling. The 3D culture system represents a novel in vitro model that permits stable long-term cultivation, spontaneous multi-lineage differentiation and tissue formation of pluripotent cells that is comparable to in vivo differentiation. Such a model is of interest, e.g. for the development of novel cell differentiation strategies. In addition, the 3D in vitro model could be used for teratoma studies and pluripotency assays in a fully defined, controlled environment, alternatively to in vivo mouse models.

The Dark Side:Stigma in purpose-built senior environments

This paper focuses on stigma in collective living environments for older adults, specifically multi-level campuses. We contrast two design profiles, a purpose-built campus which opened in 1997, and an older setting that grew by accretion over decades. Purpose-built housing is used as originally intended, designed, and constructed; housing built by accretion has been modified over time to meet changing needs and uses. The separation by care levels in both sites is reflected in their cultures as residents and staff relate to physical levels of care through a vocabulary of fear and stigma. Residents of the independent living building on the purpose-built campus refer to the assisted living building, accessed only through a second floor link, as "the other side" or "the dark side." In this setting we observe stigma assigned to a place in the built environment. By contrast, in the older setting built by accretion over the last century, levels of care feature a less-structured clustering of independent living and assisted living, and common areas were shared by residents from multiple care levels. We have observed less stigma associated with levels of care in this older building. Grounding our analysis in data drawn from ongoing ethnographic research, we focus on the built environment as it relates to stigma in the social environment. The paper concludes with a discussion of the importance and pervasiveness of stigma in senior environments.

Convective mixing induced by acid-base reactions

When two miscible solutions, each containing a reactive species, are put in contact in the gravity field, local variations in the density due to the reaction can induce convective motion and mixing. We characterize here both experimentally and theoretically such buoyancy-driven instabilities induced by the neutralization of a strong acid by a strong base in aqueous solutions. The diverse patterns obtained are shown to depend on the type of reactants used and on their relative concentrations. They have their origin in a combination of classical hydrodynamic instabilities including differential diffusion of the solutes involved while temperature effects only play a marginal role.

Age- and sex-standardised prevalence rates of fatigue in a large hospital-based sample of cancer patients

BACKGROUND

The aim of this longitudinal study was to determine age- and sex-standardised prevalence rates of cancer-related fatigue in different groups of patients.

METHODS

This was a prospective study in a cohort of N=1494 cancer patients investigating fatigue at three time points t1-t3 (t1: admission to hospital, t2: discharge, t3: half a year after t1). Fatigue was measured with the Multidimensional Fatigue Inventory. Age- and sex-adjusted norms were derived from a representative community sample of N=2037, using a cutoff at the 75th percentile.

RESULTS

At admission to the hospital, 32% of the patients were classified as fatigued. At discharge, the overall prevalence rate was 40%, and at half a year after t1, prevalence was 34%. Fatigue prevalence rates differed according to tumour stage, site, age, and sex of the patients.

CONCLUSION

The prevalence rates provided by this study can be used for the planning of research and clinical routine.

FC21-07 - Trends in health-related quality of life and health service use associated with comorbid diabetes and major depression in South Australia, 1998–2008

Purpose

To investigate trends in health-related quality of life and health service use associated with diabetes and/or major depression in South Australia from 1998 to 2008.

Methods

Data analyzed were from 9,059 persons aged ≥15 years who participated in representative surveys of the South Australian population in 1998, 2004 and 2008. Major depression was determined using the mood module of the Primary Care Evaluation of Mental Disorders (PRIME-MD). Diagnosed diabetes and health service use was determined by self-report. Health-related quality of life was assessed using the 36-item Short-Form Health Survey (SF-36) and the 15-item Assessment of Quality of Life (AQoL) instruments. Weighted age-standardized and multiple-adjusted means of dependent measures were computed.

Results

The prevalence of diabetes only, major depression only, and comorbid diabetes and major depression increased by 74%, 36% and 53% from 1998 to 2008. Mean health-related quality of life scores were 9% to 41% lower (worse), and health service use was 49% higher for persons with comorbid diabetes and major depression than for those with diabetes only (all P-values < 0.05), consistently over the 10-year period.

Conclusions

If past trends continue, our results suggest that the population health and economic burden of comorbid diabetes and major depression will grow similarly over the next decade or so. These trends have important implications for making health policy and resource allocation decisions.