CFD结合降阶模型预测阵风响应

传统的阵风响应主要在频域内进行分析，气动载荷基于线性方法计算，不能考虑黏性和跨声速流动影响．飞机设计需考虑不同频率和不同形状阵风的响应，基于CFD的阵风响应预测由于计算工况太多，工作量巨大．本文发展了一种CFD结合非定常气动力ARMA（autoregressive—moving—averagemodel）降阶模型的阵风响应分析方法，CFD只要针对给定频率和形状的一种阵风响应进行计算，对获得的气动力时间历程运用线性最小二乘法参数辨识ARMA降阶模型的系数，则对任意频率和形状的阵风，代入降阶模型即可确定该阵风的响应，大大提高了计算效率．为效验发展的方法，先计算NACA0012翼型在低马赫数0．11的阵风响应，通过对比CFD、ARMA降阶模型及早期发展的不可压阵风响应预测方法的结果，验证了方法的有效性．再对比CFD、ARMA在跨声速马赫数0．8的阵风响应预测结果，证实所发展的方法对跨声速阵风响应预测亦是有效的．

A comparison of methods for the coupled analysis of floating structures

The dynamic analysis of a deepwater floating platform and the associated mooring/riser system should ideally be fully coupled to ensure a reliable response prediction. It is generally held that a time domain analysis is the only means of capturing the various coupling and nonlinear effects accurately. However, in recent work it has been found that for an ultra-deepwater floating system (2000m water depth), the highly efficient frequency domain approach can provide highly accurate response predictions. One reason for this is the accuracy of the drag linearization procedure over both first and second order motions, another reason is the minimal geometric nonlinearity displayed by the mooring lines in deepwater. In this paper, the aim is to develop an efficient analysis method for intermediate water depths, where both mooring/vessel coupling and geometric nonlinearity are of importance. It is found that the standard frequency domain approach is not so accurate for this case and two alternative methods are investigated. In the first, an enhanced frequency domain approach is adopted, in which line nonlinearities are linearized in a systematic way. In the second, a hybrid approach is adopted in which the low frequency motion is solved in the time domain while the high frequency motion is solved in the frequency domain; the two analyses are coupled by the fact that (i) the low frequency motion affects the mooring line geometry for the high frequency motion, and (ii) the high frequency motion affects the drag forces which damp the low frequency motion. The accuracy and efficiency of each of the methods are systematically compared. Copyright © 2007 by ASME.

Lovastatin production by Aspergillus terreus using lignocellulose biomass in large scale packed bed reactor

The effect of superficial air velocity on lovastatin production by Aspergillus terreus PL10 using wheat bran and wheat straw was investigated in a 7 l and a 1200 l packed bed reactor. Mass transfer and reaction limitations on bioconversion in the 1200 l reactor was studied based on a central composite design of experiments constructed using the superficial air velocity and solid substrate composition as variables and lovastatin production as response.
The surface response prediction showed a maximum lovastatin production of 1.86 mg g-1 dry substrate on day 5 of the bioconversion process when the reactor was operated using 0.19 vvm airflow rate (23.37 cm min-1 superficial air velocity) and 54% substrate composition (wC). Lovastatin production did not increase significantly with superficial air velocity in the 7 l reactor. Variation in temperature and exit CO2 composition was recorded, and the Damköhler number was calculated for lovastatin production at these two scales. The results showed that in larger reactors mass transfer limitation controlled bioconversion while in smaller reactors bioconversion was controlled by reaction rate limitations. In addition, mass transfer limitations in larger reactors reduced the rate of metabolic heat removal, resulting in hot spots within the substrate bed.

Serum estradiol: oocyte ratio as a predictor of reproductive outcome: an analysis of data from >9000 IVF cycles in the Republic of Ireland

Purpose The purpose of this study was to evaluate the serum estradiol (E2) per oocyte ratio (EOR) as a function of selected embryology events and reproductive outcomes with IVF. Methods This retrospective analysis included all IVF cycles where oocyte collection and fresh transfer occurred between January 2001 and November 2012 at a single institution. Patients were divided by three age groups (<35, 35–39, and ≥40 years) and further stratified into nine groups based on EOR (measured in pmol/L/oocyte). Terminal serum E2 (pmol/mL) was recorded on day of hCG trigger administration, and fertilization rate, cleavage rate, number of good quality embryos, and reproductive outcomes were recorded for each IVF cycle. Results During the study interval, 9109 oocyte retrievals were performed for 5499 IVF patients (mean = 1.7 cycles/patient). A total of 63.4 % of transfers were performed on day 3 (n = 4926), while 36.6 % were carried out on day 5 (n = 2843). Clinical pregnancy rates were highest in patients with EOR of 250–750 and declined as this ratio increased, independent of patient age. While the odds ratio (OR) for clinical pregnancy where EOR = 250–750 vs. EOR > 1500 was 3.4 (p < 0.001; 95 % CI 2.67–4.34), no statistically significant correlation was seen in fertilization, cleavage rates or number of good quality embryos as a function of EOR. Conclusions Predicting reproductive outcomes with IVF has great utility both for patients and providers. The former have the opportunity to build realistic expectations, and the latter are better able to counsel according to measured clinical parameters. A better understanding of follicular dynamics and ovarian response to gonadotropin stimulation could optimize IVF treatments going forward.

Lights and Shadows about the Effectiveness of IVF in HIV Infected Women: A Systematic Review

Background. HIV infected women have higher rates of infertility. Objective. The purpose of this literature review is to evaluate the effectiveness of fresh IVF/ICSI cycles in HIV infected women. Materials and Methods. A search of the PubMed database was performed to identify studies assessing fresh nondonor oocyte IVF/ICSI cycle outcomes of serodiscordant couples with an HIV infected female partner. Results and Discussion. Ten studies met the inclusion criteria. Whenever a comparison with a control group was available, with the exception of one case, ovarian stimulation cancelation rate was higher and pregnancy rate (PR) was lower in HIV infected women. However, statistically significant differences in both rates were only seen in one and two studies, respectively. A number of noncontrolled sources of bias for IVF outcome were identified. This fact, added to the small size of samples studied and heterogeneity in study design and methodology, still hampers the performance of a meta-analysis on the issue. Conclusion. Prospective matched case-control studies are necessary for the understanding of the specific effects of HIV infection on ovarian response and ART outcome.

Capacité en matière de prise de décisions chez des récidivistes de conduite avec capacités affaiblies par l’alcool

Thomas G. Brown, Ph.D., co-directeur de recherche

Decreased fertility in poor responder women is not related to oocyte morphological status

Introduction: In women showing impaired fertility, a decreased response to ovarian stimulation is a major problem, limiting the number of oocytes to be used for assisted reproduction techniques (ART). Despite the several definitions of poor response, it is still a matter of debate whether young poor responder patients also show a decrease in oocyte quality. The objective in this study was to investigate whether poor ovarian response to the superstimulation protocol is accompanied by impaired oocyte quality.Material and methods: This study included 313 patients younger than 35 years old, undergoing intracytoplasmic sperm injection. Patients with four or fewer MII oocytes (poor-responder group, PR, n = 57) were age-matched with normoresponder patients (NR, n = 256).Results: A higher rate of oocyte retrieval and a trend towards an increase in MII oocyte rate were observed in the NR group when compared to the PR group (71.6 +/- 1.1% and 74.1 +/- 1.0% vs. 56.3 +/- 2.9% and 66.5 +/- 3.7%; p < 0.0001 and p = 0.056, respectively). A trend toward increased implantation rates was observed in the NR group when compared to the PR group (44 and 24.5 +/- 2.0% vs. 28.8 and 16.4 +/- 3.9%; p = 0.0305 and p = 0.0651, respectively).Conclusions: Low response to ovarian stimulation is apparently not related to impaired oocyte quality. However, embryos produced from poor responder oocytes show impaired capacity to implant and to carry a pregnancy to term.

Are poor responders patients at higher risk for producing aneuploid embryos in vitro?

Purpose To test the hypothesis that aged women with poor ovarian response express an increase on embryo chromosomal alterations when compared to aged women who presented normal response.Methods Couples undergoing intracytoplasmic sperm injection cycles with preimplantation genetic screening, were subdivided into two groups: Poor Responder group (n = 34), patients who produced a parts per thousand currency sign4 oocytes; and Normoresponder group (n = 50), patients who produced a parts per thousand yen5 oocytes. Groups were compared regarding cycles' outcomes and aneuploidy frequency.Results There were no significant differences between and groups regarding the fertilization rate (p = 0.6861), clinical pregnancy (p = 0.9208), implantation (p = 0.6863), miscarriage (p = 0.6788) and the percentage of aneuploid embryos (p = 0.270). Embryo transfer rate was significantly lower on poor responder group (p = 0.0128) and logistic regression confirmed the influence of poor response on the chance of embryo transfer (p = 0.016).Conclusions Aged females responding poorly to gonadotrophins are not at a higher risk for producing aneuploid embryos in vitro.

Superovulation in mares: Limitations and perspectives

Superovulation is an important tool for routine use in equine embryo transfer (ET) in order to reduce the costs and to enhance the efficiency of ET programs. Satisfactory superovulatory answers (2-7 ovulations) have been reported in mares treated with Equine Pituitary Extract (EPE) and more recently using a commercial Equine FSH. However, embryo recovery rates have been inconsistent and below expectations (20-50% embryos/ovulation). Recent studies have shown that superovulatory treatment leads to disturbances in oocyte maturation and transport, especially in mares with a high ovarian response. Higher and more consistent embryo recovery rates per ovulation have been observed in mares treated with lower doses of EPE. This paper presents a review of recent studies related to superovulation in mares.

Effects of two estradiol esters (benzoate and cypionate) on the induction of synchronized ovulations in Bos indicus cows submitted to a timed artificial insemination protocol

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Endocrine profiles and ovulation rate of cows superovulated with FSH following passive immunization against steroid free-bovine follicular fluid

Dez vacas multíparas, secas, foram distribuídas aleatoriamente em dois grupos de cinco animais cada. Nos dias 8 a 12 do diestro, o primeiro grupo recebeu 100 ml de anti-soro contra líquido folicular livre de esteróides (anti-LFb) produzido em ovelhas ovariectomizadas. O segundo grupo (controle) recebeu 100 ml de soro de ovelhas não-imunizadas. Seis horas após a aplicação, os dois grupos foram superovulados com FSH (18 NIH-FSH-S1 unidades) e LH (0,29 NIH-LH-S1 unidades) administrados em quantidades decrescentes durante quatro dias. Na manhã do terceiro dia, foi administrada uma dose luteolítica de cloprostenol. Duas inseminações foram realizadas 48 e 60 horas após. Os embriões foram recuperados pelo método cervical 7 dias após a primeira inseminação. Amostras de sangue foram coletadas durante todo o período experimental para determinar, por radioimunoensaio, as concentrações plasmáticas de FSH, LH e progesterona. Todas as vacas do grupo imunizado e 3 do grupo controle apresentaram mais de 2 CL. Não existiu diferença significativa (P>0,05) na taxa de ovulação entre os grupos imunizado e controle (14,4 e 9,9, respectivamente). O número de embriões recuperado não foi significativamente diferente (P>0,05) entre os grupos, embora o grupo imunizado tenha apresentado maior número de embriões transferíveis (3,4 ± 1,0 versus 0,8 ± 0,4, P<0,05). As concentrações de gonadotrofinas plasmáticas não foram correlacionadas com a taxa de ovulação ou com o número de embriões recuperados. As concentrações de progesterona plasmática foram positivamente correlacionadas (r = 0,88, P<0,01) com a taxa de ovulação. Os resultados sugerem que o anti-LFb, aplicado antes da superovulação, não reduz a variabilidade da resposta ovariana.

RELATIONSHIP BETWEEN PLASMA 17-BETA ESTRADIOL ON THE DAY OF ESTRUS AND NUMBER OF VIABLE EMBRYOS IN BOS-INDICUS (NELLORE) COWS SUPEROVULATED WITH FSH

Thirteen cows, Bos indicus, of the Nellore breed were superovulated with 22 mg of follicle stimulating hormone (FSH) administered by intramuscular route during four consecutive days (D10, D11, D12 and D13), starting on the 10th day of the estrous cycle (day 0 = estrus). Prostaglandin (PGF2alpha, 1.0 mg, im) was administered on D12, 48 h after the first FSH injection, for the induction of estrus on D14, when artificial insemination was performed. Seven days later (D21 of the cycle), embryos were collected, and evaluated, and the ovarian response was estimated on the basis of number of corpora lutea determined by rectal palpation. Blood samples were obtained for the determination of plasma 17-beta estradiol on D10, D11, D12, D13, D14 and D21 and plasma progesterone on D14 by RIA. The donors were divided into two groups according to progesterone levels on D14, the day of the induced estrus (GI: P4 less-than-or-equal-to 1.00 ng/ml, N = 5 and GII: P4 > 1.00 ng/ml, N = 8). A linear positive correlation was observed between plasma 17-beta estradiol concentration on the day of estrus and viable embryo number. We conclude that plasma 17-beta estradiol and progesterone concentrations on the day of estrus can be used to predict the viability of embryos recovered from Nellore cows superovulated with FSH.

Abordagem diagnóstica dos pacientes com suspeita de trombose venosa profunda dos membros inferiores

Deep venous thrombosis is a relatively common disease, which can present pulmonary embolism as a complication in its acute phase, and later the post-thrombotic syndrome. Thus, diagnosis should be made as soon as possible, in order to prevent or minimize such complications. Several studies have shown that the symptoms and the clinical signs are inaccurate for the deep venous thrombosis diagnosis and that complementary exams are necessary. As an attempt to simplify the patients' assessment, Well et al., in 1997, developed a clinical prediction index that combines symptoms, signs and risk factors for deep venous thrombosis and managed to make a simpler approach through an association of this index with the complementary exams. Phlebography has been considered the gold standard of complementary exams. However, since it is an invasive exam and thus subject to complications, other diagnostic methods were introduced aiming at making the diagnostic approach simpler and less invasive. Doppler ultrasound, duplex scan, impedance plethysmography, computed tomography, and blood tests such as the D-dimer are some of the available methods for assessing the patient with suspicion of deep venous thrombosis. Among them, duplex scan has shown excellent accuracy and it is currently widely accepted as the first choice test for approaching the patient with deep venous thrombosis. Several authors have suggested an association of diagnostic methods to simplify and make the assessment of such patients more cost-effective, leading to the introduction of a wide range of diagnostic strategies. The different diagnostic methods used for assessing deep venous thrombosis are discussed, as well as a review of the literature on the accuracy, advantages and disadvantages of these methods. Copyright © 2005 by Sociedade Brasileira de Angiologia e Cirurgia Vascular.

Uma revisão sistemática sobre o uso de agonistas e antagonistas do GnRH em pacientes más respondedoras à estimulação ovariana

The purpose of this investigation was to make a systematic review of the medical literature in order to compare the efficacy of GnRH antagonists and agonists for poor responders to ovarian stimulation. According to the data collected, the use of GnRH antagonist protocols showed better results in comparison to long protocols with a GnRH agonist regarding the following aspects: lower cycle cancellation rate due to poor ovarian response; higher number of oocytes retrieved; higher clinical pregnancy rate per initiated cycle. Nevertheless, these results were not observed when the flare-up protocols of GnRH agonists were used. Moreover the number of oocytes retrieved with GnRH agonist was significantly higher in relation to the GnRH antagonist.

Locus no cromossomo 19 influencia positivamente o número de oócitos recuperados em ciclos estimulados

Objective: To evaluate if identified loci associated with normal age of menopause variation and early menopause can account for the poor response to controlled ovarian stimulation. Methods: A total of 71 patients, with age ≤ 35 years old, undergoing intracytoplasmic sperm injection were tested for three of the four newly identified genetic variants associated with normal variation in menopausal age and early menopause. Patients were divided into two groups: poor responder group (PR group, n=21) and normoresponder group (NR group, n=50). The influence of risk allele frequency on the response to controlled ovarian stimulation (COS) was evaluated. Logistic regression models were used. Results: There was no significant difference in the incidence of the genetic variants between NR and PR group. The risk allele for chromosome 19 variant (rs4806660) demonstrated a protective effect. The presence of a risk allele, either in homozygosis or in heterozygosis, was associated with an increased response to COS, resulting in an elevated number of follicles (Coef: 2.54, P= 0.041) and retrieved oocytes (Coef: 1.41, P= 0.041). Conclusions: Genetic variants rs244715, rs9379896 and rs4806660 are not risk factors for poor ovarian response. Instead, rs4806660 is associated with higher number of follicles and retrieved oocytes. It could be hypothesized that rs4806660 is associated with an increased response to gonadotrophin stimulus. © Todos os direitos reservados a SBRA - Sociedade Brasileira de Reprodução Assistida.