Supersonic jet noise source distributions.

The purpose of this work is to examine the noise source distributions of shock-containing supersonic jets at various pressure ratios corresponding to fully expanded Mach numbers ranging from 1.0 to 1.4 in intervals of 0.2 for various nozzle exit diameters. Source location measurements using a phased array (beamforming), farfield jet noise measurements, and schlieren flow visualization are presented. It is found that supersonic noise source distributions are more complex than those of subsonic jets. The source distributions for supersonic jets can be divided into three different Strouhal regions. At low Strouhal numbers ( fD/U≤0.3), the noise source distributions appear very similar to those of a subsonic jet, as reported in open literature. This Strouhal region is dominated by jet-mixing noise associated with small-scale turbulence mixing. At high Strouhal numbers ( fD/U≥1.0), the noise source distributions are comprised of several repetitive sources at various discrete downstream jet locations that produce noise at all frequencies. The locations of these sources roughly correspond to the shock cells in the jet, and thus, vary with jet Mach number. Another region exists at Strouhal numbers between these two regions ( 0.3

Shared motherhood IVF: high delivery rates in a large study of treatments for lesbian couples using partner-donated eggs.

Shared motherhood IVF treatment is becoming increasingly accepted among assisted reproductive techique practitioners and patients in Europe, although data on its overall efficiency remain scarce. This 6-year retrospective study from a single, private, UK HFEA-regulated centre included consecutive lesbian couples (n = 121) undergoing shared motherhood IVF treatment (141 cycles). Recipients were more parous and had undergone more previous intrauterine insemination and IVF treatments than donor partners, who had slightly higher ovarian reserve markers than recipients. Indications in most cycles (60%) were non-medical. Most (79%) egg-providers were stimulated with gonadotrophin releasing hormone antagonist protocol, and no moderate or severe cases of ovarian hyperstimulation syndrome (OHSS) arose. A total of 172 fresh and vitrified-warmed embryo transfers were carried out: 70% at the blastocyst-stage and 58% involved a single embryo. Cumulative live birth rate per receiver was 60% (72/120), and twin delivery rate was 14% (10/72). Perinatal outcome parameters were better for singleton than twin pregnancies, although the latter also achieved generally favourable outcomes. No significant difference in cumulative outcomes were found between synchronized and non-synchronized cycles. Shared motherhood IVF combines ovarian stimulation with single blastocyst transfer to provide a safe and effective treatment modality offering reassuring obstetrical and perinatal outcomes.

Advanced oocyte cryopreservation will not undermine the practice of ethical egg sharing.

The fear that the ethics and practice of egg sharing will be undermined by the growing success of oocyte cryopreservation is not based on published evidence. Separate contracts and directed counselling of donors and recipients as required by law in the UK provide protection against potential pitfalls with egg sharing. The cost and waiting time for egg donation might even fall should oocyte cryopreservation become a practicable procedure.

Minimizing risk in anonymous egg donation.

Assisted conception carries with it known and putative medical and surgical risks. Exposing healthy women to these risks in order to harvest eggs for donation when a safer alternative exists is morally and ethically unacceptable. Egg sharing minimizes risk and provides a source of eggs for donation. Anonymity protects all parties involved and should not be removed.

Should non-patient volunteers donate eggs?

Egg donation is associated with medical and surgical risks regardless of the source of eggs, be it through commercial, altruistic or more recent egg-share donors. Egg sharing is the only system that does not turn a healthy woman (the donor) into a patient. Using carefully selected egg-share donors, pregnancy rates for both donor and recipient are as good as any egg-donation programme, with one cohort of eggs being used with more efficiency. We propose that anonymous egg sharing, as licensed by the Human Fertilisation and Embryology Authority (HFEA), minimizes risk, is ethically sound and should be considered as the only acceptable form of anonymous egg donation.

One hundred and three concurrent IVF successes for donors and recipients who shared eggs: ethical and practical benefits of egg sharing to society.

Egg sharing is a form of egg donation where complete strangers can collaborate anonymously to overcome their involuntary childlessness. In a retrospective analysis, results of egg sharing treatments were analysed in 37 consecutive donors and 39 recipients who had achieved concurrent success following IVF treatment. The interval between being accepted onto the programme and receiving treatment was less than 6 months for most patients. Births of 103 infants are expected. Multiple pregnancy rates were high and equivalent in both the groups (donors 32.4%, recipients 25.6%) despite the original number of eggs available being halved at egg collection and equal numbers being allocated to donors and recipients. On average fewer than six eggs were required for the birth of each baby. More successes are expected in time as 33 couples (43.4%) have their excess embryos stored for future use. The programme avoided the need to advertise for donors. This had particular significance for members of minority ethnic groups. It is surmised that promotion of concurrent treatment of egg sharers and recipients will attract funds from insurance providers or health boards who are unimpressed by IVF treatments with indifferent success rates and runaway costs. In the event of such funds materializing, meagre NHS resources for IVF treatment could be better focused. Overall, the benefit derived from applying the simultaneous treatment of anonymous donors and recipients is so compelling as to make it the preferred IVF option for qualifying couples.

Severe haemophilia following use of donor eggs: implications for screening of prospective donors.

Oocyte donation has become a common treatment modality for a range of infertility conditions. The Shared Egg Donation (SED) scheme is one of various strategies that now exist to try and overcome shortages, that have invariably occurred from the very success of oocyte donation procedures. Despite a reassuring positive profile that has been demonstrated, some residual concerns still exist with regard to the SED programme. We report the first case of severe haemophilia following use of donor eggs in the SED scheme. The case has not only illustrated potential problems that can occur with egg donation schemes, but also suggested a plausible model on which to base future management of similar cases. The case furthermore illustrates that there is no substitute for 'good practice' in ensuring those risks and concerns of egg donation programmes are kept to acceptable limits.

Cancer of the colon in an egg donor: policy repercussions for donor recruitment.

This paper describes the tragic case of a young woman who died of cancer of the colon after successfully donating eggs to her younger sister. Although there is no direct link between her operation and the subsequent development of bowel carcinoma, this case imparts a feeling of unease when seen in conjunction with other cases reported during the last few years. It is a reminder that little is known of the long-term consequences of some aspects of assisted conception. Women undergoing ovarian stimulation for themselves or a matched recipient have the right to be advised, in an agreed format, that there is some concern about unproven potential risks from the stimulatory drugs. The safety of egg donors must assume priority over all other considerations, including lack of donors or any moral position. The recent decision by the Human Fertilisation and Embryology Authority (HFEA) to withdraw any form of payment or recompense to egg donors does not seem to us to be based on a balance of scientific advances, patient needs and the ethics of gamete supply. They state that the intention to withdraw payments was implicit in the 1990 Human Fertilisation and Embryology (HFE) Act. However the Act was based on the Warnock report made 6 years earlier. Even in 1990 ovum donation was uncommon and fertility drugs had not yet caused any unease. The Act provided the HFEA with discretionary powers to issue directions so that the future policies would be consistent with any emerging new medical evidence. It is imperative that the HFEA provide convincing evidence on how the current policy of payment to donors harms society, donors or recipients, and how in the UK the new policy will improve medical practice in assisted conception. Successful pilot studies must precede the implementation of any new policy. Failure to do this could cause irreversible harm to the practice of assisted conception using donor gametes, which will ultimately be against the basic aims of the 1990 HFE Act.

Pregnancy following intracytoplasmic sperm injection treatment with dead husband's spermatozoa: ethical and policy considerations.

This paper describes the first pregnancy in a childless widow after intracytoplasmic sperm injection (ICSI) treatment with her deceased husband's spermatozoa which had been stored for nearly 3 years before use. Before his death the husband had received treatment for testicular cancer and he had given the appropriate written consent for the future use of his spermatozoa. Of the 10 eggs injected, six resulted in normal embryos. Three embryos were transferred and the remaining three embryos are currently stored for possible future use. The treatment resulted in a continuing singleton pregnancy. The case demonstrated the suitability of ICSI in those difficult cases where the sperm quality is extremely poor. This success is also compared with a widely debated case of another widow who was refused permission to use her deceased husband's spermatozoa. It is concluded that in the case of posthumous use of frozen spermatozoa, the current laws are conveniently applicable in a chronic illness but not so in an acute illness leading to death. In the light of the wide public debate on the issues raised by this legal case, the UK Government has also decided to conduct a review of consent procedures involving the storage and use of genetic material.

Egg sharing and egg donation: attitudes of British egg donors and recipients.

The question of payment to egg donors has recently focused the attention of both the Human Fertilisation and Embryology Authority (HFEA) and licensed clinics. An acute shortage of egg donors and the rising costs of assisted conception treatment are matters of grave concern to many patients. To understand the emotional and social effects of egg sharing and egg donation, we conducted a survey of attitudes in a group of women who had some knowledge or experience of egg donation. A total of 750 questionnaires were sent out of which 217 were returned within the specified time limit. From these, 107 respondents had experience of egg donation and 110 had made enquiries about donation. The data from these questionnaires were collated and tabulated by the National Opinion Polls (NOP) Research Group. An analysis of the data produced the following key findings: (i) donating or sharing eggs is a social issue, 94% discuss it with partners/family/friends; (ii) altruistic motives are not the prerogative of non-patient volunteers-egg share donors felt that helping the childless was as important as having a chance of in-vitro fertilization (IVF) for themselves; (iii) the treatment procedure causes the most anxiety for egg donors. The recipients were most concerned about delays, donor characteristics and how the eggs were allocated; (iv) most respondents (65%) with prior experience of egg sharing would do it again - 63% of egg share donors, 72% of egg share recipients; (v) cash rewards to egg donors and outright advertising for donors were rejected by 64 and 62% of the sample respectively; and (vi) counselling was highly valued and there were no instances of 'shattered lives' after treatment. The findings do not support the recently announced intentions of the HFEA to disallow payment to gamete donors on the grounds of devalued consent. There is no precedent in modern medicine for egg sharing. The patients surveyed drew a clear distinction between egg sharing and financial rewards. As long as egg donation is not covered by the National Health Service, it is fairer to offer egg sharing than to refuse treatment to those unable to pay.