Design of a slender tuned ultrasonic needle for bone penetration

This paper reports on an ultrasonic bone biopsy needle, particularly focusing on design guidelines applicable for any slender tuned ultrasonic device component. Ultrasonic surgical devices are routinely used to cut a range of biological tissues, such as bone. However the realisation of an ultrasonic bone biopsy needle is particularly challenging. This is due to the requirement to generate sufficient vibrational amplitude capable of penetrating mineralised tissue, while avoiding flexural vibrational responses, which are known to reduce the performance and reliability of slender ultrasonic devices. This investigation uses finite element analysis (FEA) to predict the vibrational behaviour of a resonant needle which has dimensions that match closely to an 8Gx4inch bone marrow biopsy needle. Features of the needle, including changes in material and repeated changes in diameter, have been included and systematically altered to demonstrate that the location of and geometry of these features can significantly affect the resonant frequency of bending and torsional modes of vibration while having a limited effect on the frequency and shape of the tuned longitudinal mode. Experimental modal analysis was used to identify the modal parameters of the selected needle design, validating the FEA model predictions of the longitudinal mode and the close flexural modes. This verifies that modal coupling can be avoided by judicious small geometry modifications. Finally, the tuned needle assembly was driven under typical operational excitation conditions to demonstrate that an ultrasonic biopsy needle can be designed to operate in a purely longitudinal motion

Airline planning benchmark problems—Part II : passenger groups, utility and demand allocation

This paper is the second of two papers entitled “Airline Planning Benchmark Problems”, aimed at developing benchmark data that can be used to stimulate innovation in airline planning, in particular, in flight schedule design and fleet assignment. The former has, to date, been under-represented in the optimisation literature, due in part to the difficulty of obtaining data that adequately reflects passenger choice, and hence schedule revenue. Revenue models in airline planning optimisation only roughly approximate the passenger decision process. However, there is a growing body of literature giving empirical insights into airline passenger choice. Here we propose a new paradigm for passenger modelling, that enriches our representation of passenger revenue, in a form designed to be useful for optimisation. We divide the market demand into market segments, or passenger groups, according to characteristics that differentiate behaviour in terms of airline product selection. Each passenger group has an origin, destination, size (number of passengers), departure time window, and departure time utility curve, indicating willingness to pay for departure in time sub-windows. Taking as input market demand for each origin–destination pair, we describe a process by which we construct realistic passenger group data, based on the analysis of empirical airline data collected by our industry partner. We give the results of that analysis, and describe 33 benchmark instances produced

Ultrasonic needles for bone biopsy

Bone biopsy is an invasive clinical procedure where a bone sample is recovered for analysis during the diagnosis of a medical condition. When the architecture of the bone tissue is required to be preserved, a core-needle biopsy is taken. Although this procedure is performed while the patient is under local anaesthesia, the patient can still experience significant discomfort. Additionally, large haematoma can be induced in the soft tissue surrounding the biopsy site due to the large axial and rotational forces which are applied through the needle to penetrate bone. It is well documented that power ultrasonic surgical devices offer advantages of low cutting force, high accuracy and preservation of soft tissues. This paper reports a study of the design, analysis and test of two novel power ultrasonic needles for bone biopsy that operate using different configurations to penetrate bone. The first utilises micrometric vibrations generated at the distil tip of a full-wavelength resonant ultrasonic device, while the second utilises an ultrasonic-sonic approach where vibrational energy generated by a resonant ultrasonic horn is transferred to a needle via the chaotic motion of a free-mass. It is shown that the dynamic behaviour of the devices identified through experimental techniques closely match the behaviour calculated through numerical and FEA methods, demonstrating that they are effective design tools for these devices. Both devices were able to recover trabecular bone from the metaphysis of an ovine femur, and the biopsy samples were found to be comparable to a sample extracted using a conventional biopsy needle. Furthermore, the resonant needle device was also able to extract a cortical bone sample from the central diaphysis, which is the strongest part of the bone, and the biopsy was found to be superior to the sample recovered by a conventional bone biopsy needle

Ovarian function and fertility preservation for young people treated for cancer

Further advances in the treatment of young people with cancer have led to improved survival, with 85.6% 5-year relative survival for ages 0–14 in the USA for the years 2010–2016 [18]. However, successful cancer treatment during childhood can cause infertility and premature ovarian insufficiency (POI) in some patients [20, 33]. The risk of developing POI is dependent on a number of factors, which include the nature of the underlying disease and the planned therapy. Both chemotherapy and radiotherapy have been shown to affect ovarian function either directly by depleting the primordial follicle pool or indirectly via effects on hormonal regulation of ovarian function.Postprin

The effect of radiotherapy on the human reproductive system

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Fertility preservation in pre-pubertal girls with cancer : the role of ovarian tissue cryopreservation

Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.With increasing numbers of survivors of cancer in young people future fertility and ovarian function are important considerations that should be discussed before treatment commences. Some young people, by nature of the treatment they will receive, are at high risk of premature ovarian insufficiency and infertility. For them, ovarian tissue cryopreservation (OTC) is one approach to fertility preservation that remains both invasive and for young patients experimental. There are important ethical and consent issues that need to be explored and accepted before OTC can be considered established in children with cancer. In this review we have discussed a framework for patient selection which has been shown to be effective in identifying those patients at high risk of premature ovarian insufficiency (POI) and who can be offered OTC safely.PostprintPeer reviewe

Human ovarian reserve from conception to the menopause

Current understanding is that the human ovary contains a fixed number of several million non-growing follicles (NGF), established by five months of gestational age, that declines with increasing age to the menopause when approximately 1,000 NGF remain at an average age of 50-51 years. With approximately 450 ovulatory monthly cycles in the normal human reproductive lifespan, this progressive decline in NGF numbers is attributed to follicle death by apoptosis. Individual histological studies have quantified NGF numbers over limited age ranges. However, no model describing the rate of establishment and decline of the NGF population from conception to menopause has been previously reported. Here we describe the best fitting model of the age-related NGF population in the human ovary from conception to menopause. Our model matches the log-adjusted NGF population to a five-parameter asymmetric double Gaussian cumulative (ADC) curve (r2 = 0.81). Furthermore we found that the rate of NGF recruitment into growing follicles for all women increases from birth until approximately age 14 years (coinciding with puberty) then decreases towards the menopause. The explanation for this new finding remains unclear but is likely to involve both paracrine and endocrine factors. We describe and analyse the best fitting model for the establishment and decline of human NGF; our model extends our current understanding of human ovarian reserve

Family size and duration of fertility in female cancer survivors : a population based analysis

Funder: R.A.A. reports grant from Medical Research Council for the submitted work (Grant No. MR/N022556/1). T.W.K. has nothing to disclose. D.S.M. has nothing to disclose. W.H.B.W. has nothing to disclose.Objective: To assess family size and timescale for achieving pregnancy in women who remain fertile after cancer. Design: Population-based analysis. Setting: National databases. Patient(s): All women diagnosed with cancer before the age of 40 years in Scotland, 1981–2012 (n = 10,267) with no previous pregnancy; each was matched with 3 population controls. Intervention(s): None. Main Outcome Measure(s): The number and timing of pregnancy and live birth after cancer diagnosis, to 2018. Result(s): In 10,267 cancer survivors, the hazard ratio for a subsequent live birth was 0.56 (95% confidence interval, 0.53–0.58) overall. In women who achieved a subsequent pregnancy, age at live birth increased (mean ± SD, 31.2 ± 5.5 vs. 29.7 ± 6.1 in controls), and the family size was lower (2.0 ± 0.8 vs. 2.3 ± 1.1 live births). These findings were consistent across several diagnoses. The interval from diagnosis to last pregnancy was similar to that of controls (10.7 ± 6.4 vs. 10.9 ± 7.3 years) or significantly increased, for example, after breast cancer (6.2 ± 2.8 vs. 5.3 ± 3.3 years) and Hodgkin lymphoma (11.1 ± 5.1 vs. 10.1 ± 5.8 years). Conclusion(s): These data quantify the reduced chance of live birth after cancer. Women who subsequently conceived achieved a smaller family size than matched controls, but the period of time after cancer diagnosis across which pregnancies occurred was similar or, indeed, increased. Thus, we did not find evidence that women who were able to achieve a pregnancy after cancer had a shorter timescale over which they have pregnancies.Publisher PDFPeer reviewe