EFFECTS OF ULTRAVIOLET RADIATION ON THE IMMUNE SYSTEM IN HUMANS

In experimental animals, exposure to UV-B radiation produces selective alterations of immune function which are mainly in the form of suppression of normal immune responses. This immune suppression is important in the development of nonmelanoma skin cancer, may influence the development and course of infectious disease and possibly protects against autoimmune reactions. The evidence that this form of immune suppression occurs in humans is less compelling and very incomplete. The wavelengths of radiation most affected by a depletion of the stratospheric ozone layer are those known to be most immunosuppressive in animals and it is likely that such depletion will increase any suppressive effect of sunlight on immunity in humans. In addition to establishing whether or not UV-B radiation can cause suppression of immune function in humans, studies are required to determine if melanin can provide protection against such suppression, the role of this suppression in the pathogenesis of skin cancer, the development of infectious disease and vaccine effectiveness, and the capacity for humans to develop adaptive, protective mechanisms which may limit damage from continued exposure to UV-B radiation.     

Implementation of ISO 9001 in a medical testing laboratory

 The Department of Clinical Chemistry and Molecular Genetics, within the Institute of Clinical Pathology and Medical Research at Westmead Hospital, is a medical testing laboratory operating within the public sector health system of New South Wales, Australia. It provides acute-care pathology services to Westmead Hospital (a 900-bed tertiary referral university teaching hospital) as well as to three district hospitals and three rural hospitals. In addition to these core clinical chemistry services, it offers approximately 150 specialised biochemistry, pharmacology, toxicology, trace metal and molecular genetics assays as a reference laboratory service. In 1993, the Department became Australia's first medical testing laboratory to be registered to ISO 9001-1987/AS3901-1987. In 1995, this certification was extended to AS/NZS ISO 9001-1994. We are currently preparing for further accreditation to ISO/IEC Guide 25-1990, with additional supplementary requirements for medical testing. This paper describes the Quality System that the Department developed and which has been successfully maintained and extended since original certification. Important features of the Quality System are: 1. Primary design of the Quality System to meet medical and customer needs, with subsequent addition of required ISO elements. 2. Use of national Quality Award criteria to identify key business processes. 3. Development of integrated technical non-conformance, customer complaint, staff suggestion, and quality system corrective action procedures. 4. Implementation without external resources. Our conclusions are that ISO 9000 Quality Systems can be applied to medical testing laboratories, and can be implemented with minimum resource costs. Improvements in technical and service quality and business performance have resulted from this process. However, implementation of ISO 9000 at the level of individual Departments is not ideal. Greater improvements are possible when this process is undertaken at the level of the entire organisation. Received: 9 September 1996 Accepted: 5 October 1996     

SENSITIVITY OF MONONUCLEAR CELLS TO UV RADIATION: EFFECT ON SUBSEQUENT STIMULATION WITH PHYTOHEMAGGLUTININ

The ability of peripheral blood mononuclear cells to incorporate ³[H] thymidine into nuclear DNA following stimulation by phytohemagglutinin is reduced by prior exposure to UV radiation in vitro : the reduction is dose and wavelength dependent. The doses required to affect this function of mononuclear cells are higher than the doses required to reduce trypan blue dye exclusion, so that following exposure to radiation populations of cells that are unable to exclude trypan blue dye are still capable of responding to phytohemagglutinin. This finding indicates that trypan blue dye exclusion may not accurately reflect the viability of cells after exposure to UV radiation.     

Ab initio quantum chemical study of the formation, decomposition and isomerization of the formaldiminoxy radical (CH2NO): comparison of the Gaussian-2 and CASPT2 techniques in the calculation of potential energy surfaces

The reaction between triplet methylene and nitric oxide, producing the formaldiminoxy (CH₂NO) radical, and the subsequent decomposition and isomerization reactions of CH₂NO have been studied using ab␣initio quantum chemical techniques that include the Gaussian-2 (G2), CASSCF and CASPT2 methods. Stationary points on the potential energy surfaces were located at MP2/6-31G(d) and CASSCF/cc-pVDZ levels of theory, while the electronic energies were determined using G2, G2(MP2), QCISD(T)/cc-pVTZ, RCCSD(T)/cc-pVTZ and CASPT2/cc-pVTZ approaches. G2 is believed to be reliable at equilibrium geometries, but the determination of certain transition state geometries and energies requires a MCSCF-based approach. The calculations suggest that CH₂NO (²A^′) forms in a barrierless reaction and could readily decompose to H+HCNO. A subsequent abstraction reaction then results in H₂+CNO. No molecular elimination channel was found. An alternative pathway is the formation of CH₂ON, which readily isomerizes to CH₂NO. Received: 8 May 1998 / Accepted: 11 August / Published online: 9 October 1998     

Interval analysis techniques for boundary value problems of elasticity in two dimensions

In this paper we prove that the L² spectral radius of the traction double layer potential operator associated with the Lamé system on an infinite sector in R² is within 10⁻² from a certain conjectured value which depends explicitly on the aperture of the sector and the Lamé moduli of the system. This type of result is relevant to the spectral radius conjecture, cf., e.g., Problem 3.2.12 in [C.E. Kenig, Harmonic Analysis Techniques for Second Order Elliptic Boundary Value Problems, CBMS Reg. Conf. Ser. Math., vol. 83, Amer. Math. Soc., Providence, RI, 1994]. The techniques employed in the paper are a blend of classical tools such as Mellin transforms, and Calderón-Zygmund theory, as well as interval analysis—resulting in a computer-aided proof.     

Nonlinear dynamics of a simplified engine-propeller system

This paper presents a procedure for studying dynamical behaviors of a simplified engine-propeller dynamical system consisting of a number of bodies of plane motions. The equation of motion of the complex system is obtained using the Lagrange equation and solved numerically using the 4th order Runge–Kutta method. Various simulations were performed to investigate the transient and steady state behaviors of the multiple body system while taking into consideration the engine pressure pulsations, nonlinear inertia of moving bodies, and nonlinear aerodynamic load. Sub-harmonics and super harmonics in the steady state responses for different power and propeller pitch settings are obtained using the fast Fourier transform. Numerical simulations indicate that the 1.5 order is the dominant order of harmonics in the steady state oscillatory motion of the crankshaft. The findings and procedure presented in the paper are useful to the aerospace industry in certifying reciprocating engines and propellers. The crankshaft oscillatory velocities obtained from the simplified rigid body model are in good agreement with the experimental data for a SAITO-450 engine and a SOLO propeller at a 6″ pitch setting.     

Determination of isotopically labelled monoesterphthalates in urine by high performance liquid chromatography-mass spectrometry

A method of analysis for monoesters of phthalic acid ('monoesterphthalates') in human urine has been developed. The method was needed to determine the hydrolysis and excretion efficiency of isotopically-labelled phthalate diesters ('phthalates') when they were fed to volunteers as part of a biomarker study to estimate total exposure to phthalates. The targeted substances were 13C-monobutylphthalate (MBP), 2H4-monobutylphthalate (MBP), 2H4-monobenzylphthalate (MBeP), 13C-monocyclohexylphthalate (MCHP), 13C-monoethylhexylphthalate (MEHP), and 13C-monoisodecylphthalate (MIDP). The monoesters in urine were deconjugated enzymatically, extracted into solvent, and then determined by high performance liquid chromatography-mass spectrometry (LC-MS) using atmospheric pressure chemical ionisation in the negative ion mode. The limits of determination were 10 ng ml(-1) for MBP, MCHP, MBeP and MEHP, and 40 ng ml(-1) for MIDP. The recovery from urine spiked at 100 ng ml(-1) was in the range from 70 to 85% except for MIDP which was lower at 55%. The between-batch reproducibility of the analysis was in the range 8 to 17% (n = 6 batches on separate days).     

Asymmetric synthesis of optically active tricarbonyliron complexes of 1,3-dienes

Asymmetric coordination of prochiral 1,3-dienes to form optically active (diene)Fe(CO)₃ complexes has been achieved by direct transfer of the Fe(CO)₃ group from chiral enone complexes.