Shear thinning is fundamental to a broad range of particle suspensions, both in nature and in industrial applications. Yet the mechanisms governing it remain unclear. In particular, the distinct, and often competing, roles of the interparticle, particle-fluid interactions and the particle surface morphology need clarity. By using non-Brownian silica particles with different morphology, surface functional groups and suspending media, here we reveal two different shear thinning mechanisms, controlled either by frictional or adhesion forces between particles. Smooth glass sphere suspensions in a polar medium (glycerol), where particles interact strongly with the solvent, showed no shear thinning even at high volume fractions (φ≥0.5), while rough silica particles, with similar size distribution, induced shear thinning behaviour at φ values of 0.25 and above. The latter is attributed to the increased frictional contacts in rough and irregular particles. Considering surface irregularity as elastically deformable asperities enabled us to estimate the critical load above which two neighbouring rough particles experience frictional contacts giving rise to shear thinning. In contrast, in a non-polar (mineral oil) solvent, with which the particles do not interact strongly, both glass spheres and the rough silicas showed a pronounced shear thinning response and yield stress behaviour at volume fractions as low as 2% v/v. The rheology of these suspensions is dictated by the adhesion forces between the particles that lead to the formation of large agglomerates, which breakdown under increasing shear. The evolution of the sheared suspensions microstructure was captured using an optical shearing cell, which also enabled us to quantify the particle agglomeration characteristics using an aggregation index. To demonstrate the generality of our approach, we modified the surface chemistry of the glass spheres by introducing hydrophobic groups (e.g. a fluorosilane or palmitic acid) to inhibit inter-particle interactions and improve the dispersion of the otherwise inherently hydrophilic glass spheres in mineral oil; as expected, this suppressed the shear thinning behaviour of the suspensions. The present results clearly elucidate alternative design routes to controlling suspension rheology, whether to promote or suppress shear thinning, offering new insights for the manufacturing and manipulation of complex particle suspensions.

Left ventricular (LV) function was assessed in 42 patients (mean age +/- SD, 18.45 +/- 3.76 years; 17 males) with type I diabetes mellitus (T1DM; mean duration 9.89 years) and in 43 healthy controls (mean age +/- SD, 18.27 +/- 3.36 years; 18 males). Systolic, diastolic cardiac function and LV dimensions were assessed using M-mode and Doppler echocardiography. Neural autonomic function was assessed by measuring RR variation during deep breathing, Valsava maneuver, 30/15 ratio, and blood pressure response to standing. Fractional shortening, peak velocity of early ventricular filling (E wave), peak velocity of LV filling (A wave), E/A ratio, deceleration time, isovolumic relaxation time, LV dimensions (interventricular septum, posterior wall thickness, end diastolic diameter [EDD] and systolic diameter [ESD]) were all comparable between patients with T1DM and controls. However, in 11 T1DM patients with microalbuminuria and/or retinopathy, EDD, ESD, E/A ratio, and E wave were all lower (p = 0.0011, p = 0.019, p = 0.0011, and p = 0.030, respectively) while, A wave, heart rate, and diastolic blood pressure were all higher (p = 0.008, p = 0.0024 and p = 0.004, respectively) compared to matched for age and sex controls. Furthermore, in six of the 11 T1DM patients with microangiopathy who had E/A <1.12 (<2 SD of the control mean), significant and marginally significant correlations were found between E/A ratio and the duration of the disease as well as the mean HbA1c of the last year (r = -0.38, p = 0.011 and r = -0.287, p = 0.064, respectively). In conclusion, it has been found that impairment of diastolic, but not systolic, LV function can be detected early in young patients with T1DM and microangiopathy.

An increased risk of different types of malignancy has been reported in patients with Noonan syndrome (NS). We describe a patient with short stature, dysmorphic features, developmental delay, and congenital cardiomyopathy. At 5 years old, he presented with abdominal pain, constipation, and evaluation with ultrasound and computed tomography scan demonstrated the presence of an abdominal mass. Total resection of the mass and consequent histology revealed an embryonal rhabdomyosarcoma. Rhabdomyosarcoma is a rare tumor in NS patients and to the best of our knowledge only 2 cases have been reported so far. The presentation underlines the importance of frequent follow-up of patients with NS, since the incidence of malignancy is low but existing.

In 14 patients suffering from relapsing chronic brucellosis who were anergic to brucella antigens, we have studied peripheral blood monocyte random migration and chemotaxis against non-specific and specific leukoattractants, as well as plasma and monocyte ascorbic acid levels. We found that all parameters studied, were significantly beneath normal, when compared to normal subjects. After the oral administration of ascorbic acid at a daily dose of 1gr for 15 consequetive days, random and directed migration against a non-specific stimulus (casein) returned to normal. Directed migration against disease associated leukoattractants (brucella melitensis and brucella abortus) antigens improved significantly, without reaching normal values. We concluded that ascorbic acid supplementation might partially restore peripheral, monocyte function and help the monocyte-macrophage system to mount an effective immune response against chronicity of brucella infection.

Higher amifostine doses are tolerable by patients with pelvic malignancies and can better protect pelvic tissues against early and short-term late effects of radiotherapy.