Control of Rheological Behaviour with Oppositely Charged Polyelectrolyte Surfactant Mixtures

Mixtures of the cationic, cellulose based polyelectrolyte JR 400 and the anionic surfactant sodium dodecylbenzene sulfonate (LAS) have been used to control the rheological behaviour of aqueous solutions. Around charge equilibrium precipitation takes place, but both for the surfactant-rich and the polymer-rich side homogeneous solutions are formed. In these monophasic regions the rheology depends strongly on the mixing ratio between the two components and highly viscous systems can be obtained on the polyelectrolyte rich side upon the addition of relatively small amounts of surfactant. Here the viscosity increases by more than four orders of magnitude before reaching the phase boundary of precipitation. Small-angle neutron scattering (SANS) showed the formation of an interconnected network of rodlike aggregates composed of a polyelectrolyte/surfactant complex, which explains the observed high viscosity due to the high degree of interconnection by the polyelectrolyte.

Nonlinear behavior of nematic platelet dispersions in shear flow

Dispersions of platelets in the nematic phase are submitted to large amplitude oscillatory shear flow and probed by high temporal resolution small angle x-ray scattering. The response displays rich dynamic and structural behavior. Under small amplitude deformations we observe an elastic response, while structurally symmetry is broken: a preferential direction of deformation is selected which induces off-plane orientation of the platelets. We associate the elastic responses with the tilting director of the platelets towards the flow direction at all strain amplitudes. At large strain amplitudes there is a yielding transition between elastic and plastic deformation, accompanied by a flipping of the director. At intermediate strain amplitudes the director has a rich dynamic behavior, illustrating the complex motion of platelets in shear flow. These observations are confirmed by steady-shear flow reversal experiments, which underline the unique character of sheared nematic platelet dispersions.

Is there a need for early post-operative x-rays in primary total knee replacements? Experience of a centre in the UK

INTRODUCTION

Early post-operative x-rays are often taken in total knee replacements (TKRs). Patient mobilisation may be delayed until these x-rays are obtained and this may prolong discharge. The aim of this study was to assess the value of such early x-rays and whether they influenced the early post-operative management of these patients.

METHODS

A total of 624 consecutive TKRs performed at the Blackpool Victoria Hospital over a 34-month period were evaluated. Plain anteroposterior and lateral x-rays were examined.

RESULTS

Two patients were found to have significant abnormalities: an undisplaced periprosthetic tibial fracture and a partial inferior pole patellar avulsion. Neither of these required further treatment or influenced mobility. No other complications were noted that changed routine post-operative management.

CONCLUSIONS

These results question the need for immediate x-rays in primary TKRs.

Alcohol misuse in patients with psoriasis: identification and relationship to disease severity and psychological distress

BACKGROUND

Moderate to severe psoriasis is associated with increased alcohol intake and excessive mortality from alcohol-related causes. Alcohol biomarkers provide an objective measure of alcohol consumption. Carbohydrate-deficient transferrin (CDT) is the single most sensitive and specific alcohol biomarker.

OBJECTIVES

To assess alcohol consumption in a cohort of patients with moderate to severe psoriasis using standard alcohol screening questionnaires and biomarkers. We investigated whether there was an association between alcohol intake, anxiety, depression and disease severity.

METHODS

Consecutive patients with chronic plaque psoriasis were recruited and completed a range of anonymized assessments. Psoriasis severity, anxiety and depression, and the impact of psoriasis on quality of life were assessed. Alcohol screening questionnaires were administered. Blood specimens were taken and γ-glutamyltransferase (γGT) and CDT were measured.

RESULTS

A total of 135 patients completed the study. Using validated questionnaires, between 22% and 32% had difficulties with alcohol. Seven per cent had CDT > 1·6% indicating a heavy alcohol intake. The Alcohol Use Disorders Identification Test (AUDIT) questionnaire was superior to other validated questionnaires in detecting alcohol misuse. There were no significant associations between measures of excessive alcohol consumption and disease severity. Excessive alcohol intake as measured by the CAGE questionnaire was associated with increased depression (P = 0·001) but other measures of alcohol excess did not correlate with psychological distress. Men had significantly more difficulties with alcohol than women (P < 0·001).

CONCLUSION

Alcohol misuse is common in patients with moderate to severe psoriasis. Screening with the AUDIT questionnaire and CDT may allow the identification of patients who are misusing alcohol and allow appropriate intervention.

Implementing surgical services in a rural, resource-limited setting: a study protocol

INTRODUCTION

There are well-established protocols and procedures for the majority of common surgical diseases, yet surgical services remain largely inaccessible for much of the world's rural poor. Data on the process and outcome of surgical care expansion, however, are very limited, and the roll-out process of rural surgical implementation in particular has never been studied. Here, we propose the first implementation research study to assess the surgical scale-up process in the rural district of Achham, Nepal.

METHODS AND ANALYSIS

Based primarily on the protocols of the WHO's Integrated Management for Emergency and Essential Surgical Care (IMEESC), this study's threefold implementation strategy will include: (1) the core IMEESC surgical care program, (2) community-based follow-up via health workers, and (3) hospital-based quality improvement programs. The implementation program will employ additional emergency and surgical care protocols developed collaboratively by physicians, nurses and the authors. This strategy will be referred to as IMEESC-Plus. This study will employ both qualitative and quantitative research methodologies to collect clinical data and information on the reception and utilisation of services. The first 18 months of the implementation process will be studied and divided into an initial phase (first 6 months) and a consolidation phase (subsequent 12 months).

DISCUSSION

This study aims to describe the logistics of the implementation process of IMEESC-Plus, and assess the quality of the resulting IMEESC-Plus services during the course of the implementation process. Using data generated from this study, larger, multi-site implementation studies can be planned that assess the scale-up of surgical services worldwide in resource-limited areas.