The spectroscopic analysis of large biomolecules is important in applications such as biomedical diagnostics and pathogen detection 1,2 , and spectroscopic techniques can detect such molecules at the nanogram level or lower. However, spectroscopic techniques have not been able to probe the structure of large biomolecules with similar levels of sensitivity. Here we show that superchiral electromagnetic fields 3 , generated by the optical excitation of plasmonic planar chiral metamaterials 4,5 , are highly sensitive probes of chiral supramolecular structure. The differences in the effective refractive indices of chiral samples exposed to left-and right-handed superchiral fields are found to be up to 10 6 times greater than that those observed in optical polarimetry measurements, thus allowing picogram quantities of adsorbed molecules to be characterised. The largest differences are observed for biomolecules that possess chiral planar 2 sheets, such as proteins with high β-sheet content, which suggest that this approach could form the basis for assaying technologies capable of detecting amyloid diseases and certain types of viruses.Since the building blocks of life are chiral molecular units such as amino acids and sugars, biomacromolecules formed from these units also exhibit chirality on molecular and supramolecular scales. Chirally sensitive (chiroptical) spectroscopic techniques, such as circular dichroism (CD), optical rotatory dispersion (ORD) and Raman optical activity (ROA), are therefore especially incisive probes of the threedimensional aspects of biomacromolecular structure and are widely used in biomolecular science 1,2 . Chiroptical methods typically measure small differences, or dissymmetries, in the interaction of left-and right-circularly polarised light, the chiral probe, with a chiral material 2 . However, the inherent weakness of these existing chiroptical phenomena usually restricts their application to samples of microgram level. Recently, Tang and Cohen 3 postulated that under certain circumstances superchiral electromagnetic fields could be produced that display greater chiral asymmetry than circularly polarised plane light waves. We have realised such superchiral electromagnetic fields are generated in the near fields of PCMs, and can greatly enhanced the sensitivity of a chiroptical measurement, enabling us to detect and characterise just a few picograms of a chiral material.PCMs were first fabricated, and shown to display large chiroptical effects such as optical rotation, by Schwanecke and co-workers 4 and Gonokami and co-workers 5 .The PCMs used in this study, Fig. 1 (a), are composed of left or right handed (LH / RH) Au gammadions, of length 400 nm and thickness 100 nm (plus a 5 nm Cr adhesion layer) deposited on a glass substrate and arranged in a square lattice with a periodicity of 800 nm. As a control we repeated all experiments using a metamaterial composed of achiral crosses with the same thickness and periodicity as the gammadions: these structures showed no dissymmetry in excita...

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A series of 238 hydronephrotic kidneys in 219 children is reported. The condition was more common in the male than in the female subject and occurred more frequently on the left side. It was often bilateral, especially in infants, with an abdominal mass as the common presenting feature. Loin or abdominal pain was the most frequent complaint in older children. In some cases hydronephrosis presented as a ruptured kidney following trauma. Only 1 patient was hypertensive. The lesion was asymptomatic in 18 cases and the incidence of urinary infection was low. Dismembered pyeloureteroplasty was the procedure of choice for reconstruction. Preliminary nephrostomy was used rarely and nephrectomy was done in 10 per cent of the kidneys. Of the 7 reoperations 4 were for persistent obstruction and 3 were because stones had formed after the pyeloplasty. The late results, assessed clinically and radiologically, have been entirely satisfactory. Many kidneys of initially doubtful value showed useful improvement after reconstructive operation and no secondary nephrectomies were performed. The only death in the series occurred 2 1/2 years postoperatively and was unrelated to the urinary tract.