Cross-flow filtration of fine suspensions through microsieves occurs in microprocessing. The interaction of particles with surfaces in microenvironments has been extensively studied, but predominantly in monolayers and not with an eye to microfiltration. Here, we introduce a microfiltration model that pertains to particles that might be seen as fine in a macroscopic environment, but are large enough to intrude significantly into the shear layer of a microchannel. Thus, particle accumulation upon the sieve couples the steady-state filtrate flux and the suspension flow through the microchannel that feeds the sieve. We envision and create a stable, stationary multilayer of particles whose thickness is shear-limited and we identify and verify the structure and parameters that limit steady filtration in this environment. At first, a packed bed of particles forms, growing into and regulated by the micro channel's shear flow. A critical shear stress is shown to determine the thickness of the bed, seen as a stationary and stable multilayer of particles through which filtration may occur. As the bed thickens, at the expense of channel area for suspension flow, surface shear stress increases until no further particle adherence is possible. We built a simple example using hard noninteracting polymer microspheres and conducted cross-flow filtration experiments over Aquamarijn™ microsieves (uniform pore size of 0.8 μm). We observed a steady cake-layer thickness and because of the simple geometry afforded by uniform spheres, we could approximate the force balance, cake resistance, and filtration rate from first principles. The good fit of our data to the proposed mechanism lays a firm basis for the semiquantitative analysis of the behavior of more complex suspensions.Critical shear stress at each filtration rate (Q f ) was plotted to demonstrate a monotonically increasing trend, aligned with our theoretical prediction.

Childhood sexual abuse remains a taboo subject and requires sensitive handling by committed and caring services (Scottish Executive, 2004). By introducing a training programme, Safe to Say, the Scottish Association of Mental Health aims to improve the confidence and competence of healthcare workers when faced with the sensitive disclosure of childhood abuse. This article aims to explore the effects of childhood sexual abuse and the attitudes of health professionals when faced with adult survivors disclosing such abuse. Despite Government strategies, there still appears to be a lack of suitable services for adult survivors of childhood sexual abuse, even though health professionals have an essential role in supporting disclosure and promoting recovery (Read et al, 2005).

In Scotland, between 25 and 30% of all GP consultations involve depression, stress or anxiety. The incidence of depression is high and rising, with mental health problems in old age being very common. Depression can be reliably diagnosed and treated in primary care, and a range of treatments are available; however, the effectiveness of all treatments is limited by non-concordance with the treatment plan. There are many reasons why medicines may not be taken as prescribed, including adverse effects, poor communication between health professional and patient, the effects of the illness, including cognitive impairment and patients' disagreement with the need for treatment. A case study on a patient with depression is presented, using the Situation, Background, Assessment, Recommendation (SBAR) format. The case study demonstrates a critical understanding of how issues of role, concordance and psychopharmacology impacted on the recovery of the patient.