Microfluidics based on ZnO/nanocrystalline diamond surface acoustic wave devices.

Surface acoustic wave (SAW) devices with 64 µm wavelength were fabricated on a zinc oxide (ZnO) film deposited on top of an ultra-smooth nanocrystalline diamond (UNCD) layer. The smooth surface of the UNCD film allowed the growth of the ZnO film with excellent c-axis orientation and low surface roughness, suitable for SAW fabrication, and could restrain the wave from significantly dissipating into the substrate. The frequency response of the fabricated devices was characterized and a Rayleigh mode was observed at ∼65.4 MHz. This mode was utilised to demonstrate that the ZnO/UNCD SAW device can be successfully used for microfluidic applications. Streaming, pumping, and jetting using microdroplets of 0.5 and 20 µl were achieved and characterized under different powers applied to the SAW device, focusing more on the jetting behaviors induced by the ZnO SAW.

A swallowed foreign body that uncovered an undiagnosed bowel pathology.

This report details a unique presentation of Crohn's disease in a patient who inadvertently swallowed the cap of a USB mass storage device and subsequently developed intestinal obstruction and underwent a limited right hemicolectomy. Imaging, photographs and histology are described with discussion of surgical outcomes.

Carbogen breathing increases prostate cancer oxygenation: a translational MRI study in murine xenografts and humans.

Hypoxia has been associated with poor local tumour control and relapse in many cancer sites, including carcinoma of the prostate. This translational study tests whether breathing carbogen gas improves the oxygenation of human prostate carcinoma xenografts in mice and in human patients with prostate cancer. A total of 23 DU145 tumour-bearing mice, 17 PC3 tumour-bearing mice and 17 human patients with prostate cancer were investigated. Intrinsic susceptibility-weighted MRI was performed before and during a period of carbogen gas breathing. Quantitative R(2)* pixel maps were produced for each tumour and at each time point and changes in R(2)* induced by carbogen were determined. There was a mean reduction in R(2)* of 6.4% (P=0.003) for DU145 xenografts and 5.8% (P=0.007) for PC3 xenografts. In all, 14 human subjects were evaluable; 64% had reductions in tumour R(2)* during carbogen inhalation with a mean reduction of 21.6% (P=0.0005). Decreases in prostate tumour R(2)* in both animal models and human patients as a result of carbogen inhalation suggests the presence of significant hypoxia. The finding that carbogen gas breathing improves prostate tumour oxygenation provides a rationale for testing the radiosensitising effects of combining carbogen gas breathing with radiotherapy in prostate cancer patients.

The resolution of optical traps created by Light Induced Dielectrophoresis (LIDEP).

Light induced dielectrophoresis (LIDEP) is a variant of the dielectrophoresis (DEP) mechanism that has been used for some time to manipulate particles in a microfluidic environment. Rather than relying on lithographically created contacts to generate the required electrical fields, the electrical contacts in LIDEP are created through the selective illumination of a photoconductor. The key question we address is how microscopic traps created via LIDEP compare to optical traps based on the gradient force, in terms of power required and trap stiffness achieved, as well as the size resolution of such a trap. We highlight the complex interplay between optical power and resolution with electrical parameters, such as the electrical resistance and applied AC Voltage. We show that for a spotsize of five micrometres and larger, particles can indeed be trapped with low power. We use trap stiffness per mW to compare LIDEP with an optical trap and show that our system is 470+/- 94 times stiffer per mW than a conventional optical trap, with no loss of resolution. We also discuss the difficulties of achieving trapping at smaller spot sizes, and that the submicron resolution possible with gradient force trapping is very difficult to realise with LIDEP.

Painful leg and missing pulses: a case report.

Popliteal artery entrapment syndrome (PAES) is a rare but potentially limb threatening anatomical anomaly occurring predominantly in young adults. We report a case of a 14 year old boy who presented with limb threatening ischaemia requiring urgent surgery. The pathology, presentation, and management are discussed.

Helicobacter pylori infection is related to atheroma in patients undergoing coronary angiography.

OBJECTIVES: Helicobacter pylori infection has been related to an increased risk of ischaemic heart disease (IHD) possibly by raising plasma fibrinogen. The evidence for this association is conflicting. Furthermore, no attempt has been made to distinguish between an effect on atheroma and thrombosis. We have determined the association of H. pylori status with IHD assessed by coronary angiography. We have also evaluated the influence of H. pylori infection on haemostatic factors. METHODS: Caucasian patients undergoing coronary angiography for suspected IHD were recruited. H. pylori status was determined by serology (Helico G). Plasma fibrinogen was measured by the Clauss assay. Coronary angiograms were assessed and significant atheroma defined as > or = 50% stenosis. A history of myocardial infarction was ascertained by WHO criteria. RESULTS: 292 patients were recruited (median age 59, 95 female); 204 (70%) patients had IHD and 185 (64%) of all patients were H. pylori-positive; 68% patients with IHD were H. pylori-positive compared with 50% without IHD (P = 0.003). When adjusted for other risk factors by logistic regression, H. pylori remained significantly associated with IHD (odds ratio = 2.4, 95% CI = 1.2-5.1, P = 0.02). H. pylori status was not related to a history of myocardial infarction. Circulating levels of PAI-1, vWF, Factor VII and fibrinogen were not related to H. pylori status. CONCLUSION: This study suggests that infection with H. pylori is associated with coronary atheroma, but that this relationship is unlikely to be mediated through raised plasma fibrinogen.

Pneumococcal pericarditis presenting as an out of hospital cardiopulmonary arrest.

Serious complications of pneumococcal pneumonia have become uncommon with effective antibiotic treatment. Purulent pericarditis is a rare though well described complication of untreated pneumococcal sepsis. A case of untreated pneumococcal pneumonia complicated by purulent pericarditis is described. This presented as an out of hospital asystolic cardiopulmonary arrest.

Preservation of autonomic function following successful reperfusion with streptokinase within 12 hours of the onset of acute myocardial infarction.

Successful reperfusion following thrombolysis results in increased heart rate variability in the first 24 hours after administration. Preservation of autonomic function may contribute to improved prognosis when coronary artery patency is restored with intravenous thrombolysis.

Giant T wave inversion associated with severe aortic regurgitation.

Two patients with haemodynamically significant aortic regurgitation and angiographically normal coronary arteries developed giant T wave inversion. The T wave abnormality partially resolved in both, following valve replacement in one and medical treatment in the other. This unusual electrocardiographic appearance may be related to myocardial ischaemia caused by increased left ventricular wall stress and changes in phasic coronary blood flow, abnormalities in cerebral perfusion associated with severe aortic regurgitation, or to coincidental neurological disease.

Resistance to ischaemic conduction failure in chronic hypoxaemia and diabetes.

Median nerve function was studied in twelve diabetic subjects, six subjects with chronic hypoxaemia and ten control subjects. Resistance to ischaemic conduction failure (RICF), a characteristic electrophysiological feature of diabetic neuropathy, was assessed by measuring the decline in median nerve action potential amplitude at minute intervals for up to 20 minutes while the arm was rendered ischaemic. Initial nerve conduction velocity and action potential amplitude was similar in all three groups. Following the onset of ischaemia the time to a 50% reduction in action potential amplitude was prolonged in both diabetic subjects and hypoxaemic subjects compared with controls. After 20 minutes of ischaemia no control subject had persisting nerve function, while function remained in 5 (80%) of hypoxaemic subjects and 10 (83%) of diabetic subjects. The time to a 50% reduction in action potential amplitude during ischaemia correlated with the blood oxygen saturation among the hypoxic subjects and haemoglobin Alc among diabetic subjects. These results are consistent with the hypothesis that hypoxia has a role in the pathogenesis of resistance to ischaemic conduction failure in diabetes.