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Objective: This study explores the feasibility and reliability of a modified ulcer-specific quality of life (QOL) questionnaire on patients suffering from venous leg ulcers. Methods: A cross-sectional survey was conducted on a cohort of patients suffering from venous leg ulcers who had been registered at Rochdale Infirmary to participate in a clinical trial. A self-administered six-page questionnaire – Freiburger Lebensqualitäts Questionnaire Assessment (FLQA) – on the QOL along with a checklist was used to collect data from March 2002 to June 2003. The feasibility and reliability of the venous leg ulcer specific questionnaire, the patient-reported QOL and their perspective on compression therapy were chosen as the main outcomes of the study. Results: A response rate of 94% was obtained, of which 56% were women and 44% were men with an average age of 63 years. Approximately 72% of respondents reported that the questionnaire was suitable to reflect their perspectives on QOL and compression therapy. The questionnaire took an average of 20 minutes to complete. The average QOL score was 45.27 in all the eight domains, where 0 reflected good QOL and 100 reflected poor QOL, indicating that the respondents' QOL had been adversely affected due to venous leg ulcers. Men had an average score of 52.0 in all the eight domains and women scored 39.0 in a 0–100 scale. Hence, comparatively, men had poorer QOL than women. Reliability was assessed using measures of internal consistency and test–retest analysis. Cronbach's alpha, α = 0.934 indicated that the survey items were highly inter-correlated. Test–retest analysis indicated that there was moderate-to-strong correlation in seven out of eight domains, which meant that the reproducibility of the FLQA questionnaire was consistent. Conclusions: The pilot survey conducted on a representative sample of patients indicated that the questionnaire is suitable and has the potential to reflect the perspective on compression therapy and overall QOL of patients suffering from venous leg ulcers. The survey tool demonstrated the clinical and research utility as a QOL outcome measure for clinical trials evaluating wound care products on patients suffering from venous leg ulcers.

Clinical trials in woundcare are conducted to assess the safety, efficacy and effectiveness of woundcare materials on patients. This paper will highlight the various designs of clinical trials, the pitfalls that commonly occur during the execution of trials, a critical literature review of previously conducted trials in woundcare, how trial design quality can be enhanced by incorporating patients’ perspective and health related quality of life measures (HRQOL), and finally the paper proposes an innovative approach in conducting a clinical trial in woundcare.

Healthcare manufacturing companies have developed many new and novel materials for wound care. They claim that the dressing materials will improve the healing progress of the wound or have a therapeutic value and have sought to assess their efficacy and effectiveness in clinical trials. These claims should be clearly supported by the perspectives of those who actually use the devices. Compression therapy, which is regarded as an effective treatment for venous leg ulcers, is far from ideal owing to a number of limitations that it possesses, such as patient discomfort, difficulty experienced in applying correct compression on the limbs, choosing a correct dressing for the wound or finding differences between the performance of various devices. It is necessary to investigate the patient's views and perspectives while randomized controlled clinical trials are conducted. In this review the concept of quality of life (QoL) and the tools used to measure QoL and studies that were conducted with patients suffering from chronic venous leg ulcers and undergoing therapy are considered, along with contributory factors to the healing process. In addition, a questionnaire modified from the original format is recommended as the suitable tool for assessing the QoL of patients suffering from venous leg ulcers while participating in clinical trials.

Clinical trials must be well designed in order to produce statistically and clinically significant results. This article describes the randomisation techniques that can prevent bias, the importance of sample size and the concept of power analysis.

Clinical trials need to be robust if practitioners are to apply their recommendations into practice. This article describes the various research designs used in wound care and the pitfalls that may compromise the reliability and validity of the results.

This paper describes a sensitive rotating-coil magnetometer in which the flux due to the earth's field or to a magnet is neutralized by that due to a current passing through a fixed concentric compensating coil which forms with the rotating coil a variable mutual inductance. It shows how the first-order correcting term due to the length of the magnet may be made to vanish if the angle of contact be suitably chosen, and that the second-order correction may be eliminated by a correct choice of the dimensions of the coil. Many experiments bearing on the theory and uses of the magnetometer are described. In particular, the ohm may be measured very simply, in terms of a mutual inductance and a period, by Weber's method of damping.

It is shown that if the ratio α/a of the radii of the concentric circles forming a simple inductometer is 0.506078, the mutual inductance is so accurately proportional to the angle through which the turning coil is displaced that the rising deviation from a linear law is less than 5 parts in a million at 7° of deflection. If the outer circle is replaced by two twin circles which are separated symmetrically with regard to the turning coil, the ratio α/a must be increased to bring about a similar approach to linearity. If a heavy dynamometer is constructed on this principle, then, over the range indicated, the deflecting couple is strictly proportional to the current-products. Moreover if such a dynamometer be damped electrically, the damping-couple is accurately proportional to the velocity and, over a range of oscillation of 14° we have a remarkably close approach to true damped simple harmonic motion. It is shown that the resistance of the oscillator circuit is very accurately given by the expression R = (CM/c)/[λT/(π2 + λ2) - λ0T0/(π2 + λ02)] where λ is the logarithmic decrement and T the period on closed circuit of the oscillator when a current C traverses the field coils, while λ0 and T0 correspond to open circuit and M is the mutual inductance between the oscillating coil and the field coils when the former is in the position of steady deflection due to the passage through it of a steady current c, in conjunction with the current C through the field coils. This expression eliminates quantities difficult to measure in Weber's method. Experimental tests are described. Table of Legendre and other functions, which facilitate the calculation of mutual inductances of the nature here considered, are appended.

In the course of a study of the magnetic moment of a number of complex compounds of the transition elements it was soon found that the values given in the literature for most of the common paramagnetic salts were not sufficiently consistent to enable any one of them to be used as a standard of reference. It was therefore decided to determine the susceptibility of nickel chloride in aqueous solution, since it was already known that this substance had a constant susceptibility over a wide range of concentrations. The nickel content of a solution can easily and accurately be estimated by precipitation with dimethyl glyoxime, so that a solution of nickel chloride forms a very suitable reference standard in calibrating apparatus designed for the measurement of magnetic susceptibilities. The method of measurement chosen was the cylinder method usually referred to as that of Gouy. In this method the force F which is exerted on a cylinder of cross-section A by a magnetic field of intensity H 1 and H 2 at the lower and upper ends of the specimen is given by F = 1/2 A ( κ - κ a ) ( H 2 1 - H 2 2 ), (1) where k is the volume susceptibility of the specimen and κ a that of the surrounding medium. The force F was measured by means of a sensitive balance using the method of swings, so that the specimen was displaced a few millimetres during the weighing. It was therefore necessary to design the magnet so as to give a large region of uniform field H 1 and a very small value of H 2 . The displacement would then cause no significant change in the difference in the squares of these fields. The determination therefore involves the measurement of H 1 and H 2 and the determination of the cross-section of the specimen A .

In the first method a sinusoidal alternating current of some 15 mA. derived from a valve oscillator and of frequency equal to that of a Konig tuning-fork is allowed to induce an equal current in a secondary circuit. The equality of amplitude of the primary and secondary currents is judged with the aid of a Westinghouse instrument rectifier. The resistance of the secondary circuit is given by the expression S=2πnradical(M2-N2), where n is the frequency, N the self-inductance of the secondary and M the mutual inductance between the primary and secondary. With standard forks of frequencies 256, 320, 384 and 512, resistances have been measured ranging from 16Ω to 67Ω. In the second method equal primary and secondary currents of known frequency are also produced and are further adjusted to be in quadrature. A simple arrangement is thereby derived which enables Campbell's two-phase alternating-current method of measuring resistance to be carried out in the laboratory. In both methods a visibly beating circuit is employed which enables the frequency of the current used to be tuned easily, with precision, to that of a valve-maintained fork. This beating circuit is also of value in checking the relative accuracy of forks whose frequencies are very approximately in simple ratio to one another.

A rotating coil of mean radius α lies symmetrically between two fixed twin coils of radius a. If the ratio α/a lies between 0.58 and 0.53 it is easy to arrange, by merely adjusting the distance between the twin coils, that the mutual inductance M between the rotating coil and the two fixed coils shall be very accurately proportional to the angle θ of displacement from the conjugate positions over a range of some 10° of arc on either side of the zeros. The constant K of the relation M = Kθ can then be accurately measured by a method here described in which θ is deduced from a mutual-inductance ratio. At the same time errors in the calibration of the inductometer used are eliminated. If such a coil spins with an angular velocity ω, while a current C traverses the fixed twin coils, a uniform e.m.f. ωCK can be drawn off a commutator on the rotating shaft and made to balance an e.m.f. CR drawn off an adjustable resistance R carrying the same current. Thus R = ωK. If now the twin coils are brought rather closer together, the law of variation of M with theta takes the form M/θ = K + Aθ2 - Bθ4 over a displacement of 35° of arc from the zeros, where A and B are very small positive constants and M/θ attains a maximum value K', where θ2 = A/2B and scarcely changes over a range of 3° in this neighbourhood. This allows larger sectors to be used on the commutator and the constant K' of the relationship R = K'ω can be accurately determined for a suitable commutator in situ. The experimental work is mainly devoted to a study of the laws of inductance on which the method depends and to the determination of the constants K and K', but preliminary spin experiments are very hopeful and resistances of between 0.32 Ω. and 0.64 Ω. have been measured absolutely by means of commutators with sector contacts of 23° and 47° of arc. Owing to the relatively large e.m.f.'s involved, the method is very sensitive and a fluxmeter can be used as the balance-detector for hand-controlled stroboscopic spins. In other experiments a synchronized television motor was used.

IN recent years, at Birkbeck College, attention has been given to various methods of measuring electrical resistance absolutely. On the eve of war, this series of researches has been brought to a conclusion by the development of a method in which the potential difference across a resistor is balanced by the average E.M.F.of a commutating generator. Although Rosa1, so far back as 1909, suggested such a method and proposed a form of apparatus, difficulties were encountered and no experimental data derived from any form of this method have been published. The method is attractive in requiring only the measurement of a frequency and a maximum mutual inductance.