40 research outputs found
Comparative Assessment of Soil-Structure Interaction Regulations of ASCE 7-16 and ASCE 7-10
This paper evaluates the consequences of practicing soil structure
interaction (SSI) regulations of ASCE 7-16 on seismic performance of building
structures. The motivation for this research stems from the significant changes
in the new SSI provisions of ASCE 7-16 compared to the previous 2010 edition.
Generally, ASCE 7 considers SSI as a beneficial effect, and allows designer to
reduce the design base shear. However, literature shows that this idea cannot
properly capture the SSI effects on nonlinear systems. ASCE 7-16 is the first
edition of ASCE 7 that considers the SSI effect on yielding systems. This study
investigates the consequences of practicing the new provisions on a wide range
of buildings with different dynamic characteristics on different soil types.
Ductility demand of the structure forms the performance metric of this study,
and the probability that practicing SSI provisions, in lieu of fixed-base
provisions, increases the ductility demand of the structure is computed. The
analyses are conducted within a probabilistic framework which considers the
uncertainties in the ground motion and in the properties of the soil-structure
system. It is concluded that, for structures with surface foundation on
moderate to soft soils, SSI regulations of both ASCE 7-10 and ASCE 7-16 are
fairly likely to result in a similar and larger structural responses than those
obtained by practicing the fixed-base design regulations. However, for squat
and ordinary stiff structures on soft soil or structures with embedded
foundation on moderate to soft soils, the SSI provisions of ASCE 7-16 result in
performance levels that are closer to those obtained by practicing the
fixed-base regulations. Finally, for structures on very soft soils, the new SSI
provisions of ASCE 7-16 are likely to rather conservative designs.Comment: ASCE Structures Congress, Fort Worth, TX, USA, April 19-21 (2018
A multi-centre randomised controlled study of pre-IVF outpatient hysteroscopy in women with recurrent IVF implantation failure: Trial of Outpatient Hysteroscopy - [TROPHY] in IVF
<p>Abstract</p> <p>Background</p> <p>The success rate of IVF treatment is low. A recent systematic review and meta-analysis found that the outcome of IVF treatment could be improved in patients who have experienced recurrent implantation failure if an outpatient hysteroscopy (OH) is performed before starting the new treatment cycle. However, the trials were of variable quality, leading to a call for a large and high-quality randomised trial. This protocol describes a multi-centre randomised controlled trial to test the hypothesis that performing an OH prior to starting an IVF cycle improves the live birth rate of the subsequent IVF cycle in women who have experienced two to four failed IVF cycles.</p> <p>Methods and design</p> <p>Eligible and consenting women will be randomised to either OH or no OH using an internet based trial management programme that ensures allocation concealment and employs minimisation for important stratification variables including age, body mass index, basal follicle stimulating hormone level and number of previous failed IVF cycles. The primary outcome is live birth rate per IVF cycle started. Other outcomes include implantation, clinical pregnancy and miscarriage rates.</p> <p>The sample size for this study has been estimated as 758 participants with 379 participants in each arm. Interim analysis will be conducted by an independent Data Monitoring Committee (DMC), and final analysis will be by intention to treat. A favourable ethical opinion has been obtained (REC reference: 09/H0804/32).</p> <p>Trail Registration</p> <p>The trial has been assigned the following ISRCTN number: ISRCTN35859078</p
Regional clinical practice patterns in reproductive endocrinology: A collaborative transnational pilot survey of in vitro fertilization programs in the Middle East
Comparison of different starting gonadotropin doses (50, 75 and 100 IU daily) for ovulation induction combined with intrauterine insemination
Why And How Should Multiple Pregnancies Be Prevented In Assisted Reproduction Treatment Programmes?
Although most professional societies have issued guidelines to diminish the number of embryos to be transferred during assisted reproductive techniques, the incidence of multiple pregnancies remains unacceptably high. The burden of morbidity and mortality seems to increase substantially with each fetus in a multiple gestation. As a result, them has been growing debate on the need to prevent multiple pregnancies. The infertility specialists who can solve the infertility problem are usually shielded from the complications of multiple pregnancies. If they were involved in the delivery and, more particularly in the care of multiple pregnancies (both financially and socially), their attitude would probably change. IVF centres should gradually reduce the mean number of embryos per transfer in terms of the cost:benefit ratio. A further reduction to one single-embryo per transfer in good cases would be similarly acceptable. Laboratory expertise is of vital importance, especially in terms of embryo culture, embryo selection, and freezing and thawing techniques in embryo transfer programmes for reducing the number of transferred embryos.WoSScopu
Pregnancy Following Intracytoplasmic Sperm Injection and Preimplantation Genetic Diagnosis After the Conservative Management of Endometrial Cancer
A rare case of a patient with conservatively treated endometrial carcinoma who conceived and delivered a healthy baby after the transfer of embryos with intracytoplasmic sperm injection (ICSI) and preimplantation genetic diagnosis (PGD) is presented. A 41-year-old woman had an office hysteroscopy in the infertility work-up and stage I endometrial adenocarcinoma was diagnosed. After conservative treatment, the patient underwent ICSI and PGD. She achieved pregnancy with two normal embryos. Two gestational sacs were observed but one of them was blighted. The patient subsequently delivered a healthy female infant. Repeated office hysteroscopy and endometrial sampling was performed after delivery. The appearance of the endometrium was normal on hysteroscopy, and the histology report was normal. The principal concern with medical therapy is that the lesion cannot be fully evaluated until the hysterectomy is performed, the nodes palpated, and the uterus is sectioned. The patient was referred to a gynaecological oncologist for definitive surgery.WoSScopu
Effect of Endometrioma Cystectomy on Ivf Outcome: A Prospective Randomized Study
The study was conducted to investigate the effect of conservative surgery of ovarian endometriomas before an ICSI cycle. Ninety-nine patients with endometrionias who were referred to an intracytoplasmic sperm injection (ICSI) cycle were enrolled in the study. The patients were prospectively randomized into two groups; group I (49 patients) underwent conservative ovarian surgery before the ICSI cycle and group II (50 patients) underwent the ICSI cycle directly. The stimulation was started 3 months after the operation in group I and directly in group II. In the ovarian surgery group, stimulation was significantly longer (14.0 days in group I and 10.8 days in group II; P = 0.001), total recombinant FSH dose was significantly higher (4575 IU in group I and 3675 IU in group II; P = 0.001), and mean number of mature oocytes was significantly lower (7.8 in group I and 8.6 in group II; P = 0.032). There was no difference in terms of fertilization (86% in group I and 88% in group II), implantation (16.5% in group I and 18.5% in group II) and pregnancy rates (34% in group I and 38% in group II). Ovarian surgery resulted in longer stimulation, higher FSH requirement and lower oocyte number, but fertilization, pregnancy and implantation rates did not differ between the groups
Co-Administration Of Metformin During Rfsh Treatment In Patients With Clomiphene Citrate-Resistant Polycystic Ovarian Syndrome: A Prospective Randomized Trial
BACKGROUND: This study aims to evaluate the impact of metformin on ovarian response when co-administered during recombinant (r)FSH using the low-dose step-up protocol in clomiphene citrate-resistant polycystic ovarian syndrome (PCOS) patients with normal glucose tolerance. METHODS AND RESULTS: Thirty-two patients were randomized to metformin (n = 16) and placebo (n = 16) groups. Hormonal assessment, a 75 g oral glucose tolerance test (OGTT) and a frequently sampled i.v. glucose tolerance test (FSIGTT) were performed before and after oral administration of metformin (850 mg twice daily) or placebo for 6 weeks. Recombinant FSH treatment was undertaken, thereafter, in women who did not ovulate on metformin (n = 10) or placebo (n = 15). There was no significant change in all insulin sensitivity indices in both groups. The only change noted was a decline in mean serum free testosterone concentration in the metformin group (P = 0.049). One patient on placebo and six patients on metformin ovulated spontaneously (P 0.05). The respective figures for pregnancy were 6.3 and 31.3% (P > 0.05). CONCLUSIONS: Metformin may restore ovulation with no improvement on insulin resistance in clomiphene citrate-resistant PCOS patients with normal glucose tolerance, but has no significant effect on ovarian response during rFSH treatment.Wo
ESR1, ESR2 and FSH Receptor Gene Polymorphisms in Combination: A Useful Genetic Tool for the Prediction of Poor Responders
Purpose: Previous studies in humans concluded that a multigenic model
including specific FSHR, ESR1 and ESR2 genotype patterns may partially
explain the poor response to FSH. The aim of our study is to analyse
three different loci -polymorphisms in ESR1 Pvu II, ESR2 Rsa I and
Ser680Asn FSH receptor gene-in a Greek population and their involvement
in stimulation outcome and pregnancy rates. Methods: Each locus was
studied alone, and in combination with the others. We performed both
restriction fragment length polymorphism analysis and real-time
polymerase chain reaction. A total of 109 normally ovulating female
patients underwent IVF or ICSI. Results: Studying each locus alone, no
significant results were drawn for ESR1 and ESR2 genes. Concerning the
FSHR polymorphism, the women carrying the AA variant presented higher
total amount of gonadotrophins used (P=0,048) and tended to have higher
number of stimulation days (P=0,057). Considering the ESR1 and FSHR gene
polymorphisms in combination, the TC/SA combination presents the highest
number of pregnancies in poor responders group (3/4 pregnancies carried
this genotype), in good responders group (4/12 pregnancies carried this
genotype) and in the total population (10/26 pregnancies carried this
genotype). Except the CC/AA combination, all other genotype combinations
presented incidence of pregnancy, with TC/SA having the highest
incidence. The CC/AA genotype presents the worst profile of ovulation
induction, confirming a poor responder profile: the total amount of
gonadotrophins used was highest in CC/AA group (P<0,05). The peak E2,
the number of follicles and of retrieved oocytes and the pregnancy rate
were significantly lower (P<0,05). This genotype combination seems to be
over-presented in the poor responders group in a statistically
significant way (P=0,038). Women with CC/AA combination have 1,5-2,4
times more risk to be poor responders in comparison with women that do
not carry that combination. Conclusion: This study supports the
hypothesis that a multigenic model, including the well studied ESR1 and
FSHR genes is involved in the controlled ovarian stimulation outcome
indicating that the CC/AA genotype presents the worst ovulation
induction profile, while the TC/SA genotype presents the higher number
of pregnancies in our population