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The flow of liquid crystals in the presence of electric fields is investigated as a possible means of flow control. The Beris-Edwards model is coupled to a free energy incorporating electric field effects. Simulations are conducted in straight channels and in junctions. Our findings reveal that local flow mediation can be achieved by the application of spatially varying electric fields. In rectangular straight channels, we report a two-stream velocity profile arising in response to the imposed electric field. Furthermore, we observe that the flow rate in each stream scales inversely with the Miesowicz viscosities, leading to the confinement of 70% of the throughput to one half of the channel. Similar flow partitioning is also demonstrated in channel junction geometries, where we show that using external fields provides a novel avenue for flow modulation in microfluidic circuits. [ABSTRACT FROM AUTHOR]

The use of nematics in microfluidic devices offers methods of flow control that are inaccessible to isotropic fluids. While nematics have been used in channel flows found in lab on chip devices, their flow and microstructure formation still needs to be fully understood in geometries with a cylindrical cross-section. This paper investigates liquid crystal flows through capillaries via 1) the Beris-Edwards (BE) model and 2) the Leslie-Ericksen (LE) model, which emerges as a limiting case (uniaxial, constant order parameter) of the BE model. We show that the microstructure distribution is controlled by the Ericksen (Er) and Deborah (De) numbers in the Beris-Edwards model. Defects at low Ericksen numbers arise when the elastic energy dominates the thermotropic energy. Defect destruction provides a new shear-thinning mechanism, which cannot be observed in the Leslie- Ericksen theory. [ABSTRACT FROM AUTHOR]

Thin films consisting of polymer solutions are typically produced through a combination of extrusion and shearing processes, where the anisotropic, non-Newtonian solution is deformed and subjected to thermal treatment. This paper investigates the shearing of polymeric thin films by studying the channel flow rheology of polymer solutions that experience yield stress. The material rheology is described by the transversely isotropic fluid (TIF) model, which contains a yield behavior term related to microstructure distortion. Our results show that this distortional stress is able to resist the pressure gradient, and non-trivial stress distributions can exist in the absence of a flow. This represents a significant improvement over existing viscosity-based yield stress models (e.g., the Heschel–Bulkley model). The unyielded state is achieved as the end result of a transient process, where a pressure gradient produces a short-lived flow that ceases when opposing stresses from microstructure distortion are produced. Predictions of the TIF model are compared with the phenomenological Saramito model. Both models are found to predict yielding when a threshold stress is exceeded. In both cases, the velocity profile is Newtonian near the wall, while plug flows are encountered close to the centerline. [ABSTRACT FROM AUTHOR]

During the processing of nematic soft solids through process flow elements (pipe bends, elbows, etc.), the constitutive behavior makes its presence felt via processing (with rheology driven effects increasing pressure drop) and the final product microstructure. This paper explores the flow and microstructure configurations of nematic liquid crystals in a pressure driven flow through 90° pipe bends with different types of wall anchoring. The governing equations of the Leslie–Ericksen theory are solved numerically in a newly developed OpenFOAM solver. We show that the bend curvature deforms the nematic axis distribution; the distortion can be driven either by elastic or hydrodynamic effects. The interaction between the nematic microstructure and flow field generates non-zero normal stresses (in the radial, azimuthal, and streamwise directions), which produce a secondary flow and increase pressure losses. The strength of the secondary flow depends on the type of wall anchoring and Ericksen number; in configurations with homeotropic anchoring, decreasing the Ericksen number increases the relative strength of the secondary flow (with respect to the mean flow velocity). Conversely, homogeneous (planar) anchoring reduces normal stresses, thus weakening the secondary flow strength. We show that as the fluid enters/leaves the bend, there is a perturbation in the transverse velocity caused by streamwise stress gradients. The perturbation magnitude depends on material properties and can be of different values at the bend exit and entrance. Finally, we show that the spatial development of the nematic field downstream of the bend exit is controlled by both material properties and the Ericksen number. [ABSTRACT FROM AUTHOR]

The assumption of homogeneous isotropic turbulence when modeling drop breakage in industrially relevant geometries is questionable. We describe the development of an anisotropic breakage model, where the anisotropy is introduced via the inclusion of a perturbed turbulence spectrum. The selection of the perturbed spectrum is itself motivated by our previous large‐eddy simulations of high‐pressure homogenizers. The model redistributes energy from small to large scales, and assumes that the anisotropic part of the Reynolds stresses is confined to the energy‐containing range. The second‐order structure function arising from the perturbed spectrum is used in the standard framework of Coulaloglou and Tavlarides to calculate breakage frequency. While the base model exhibits non‐monotonic behavior (by predicting a maximum value for a certain drop size), the effect of anisotropy is shown to increase breakage frequency in length scales larger than this peak, thereby reducing non‐monotonicity. This effect is more pronounced for small turbulence Reynolds numbers. [ABSTRACT FROM AUTHOR]

The simulation of dilute emulsions in a model ACIP2 Sonolator is investigated using computational fluid dynamics and population balance methods. Two breakage frequency models are used that differ in the expression of the drop breakage time. Drop breakage modeling based on homogenous isotropic turbulence (HIT) shows poor agreement of the Sauter mean diameter when compared to the experiments; simulations with the empirical model from Alopaeus et al. yield better agreement. By perturbing the classical HIT spectrum, it is shown that the breakage time in the empirical model corresponds to a non‐isotropic energy spectrum. Such spectra have been observed in the non‐isotropic near field in a model A Sonolator, which provides a plausible explanation of why the empirical model performs better than the HIT‐based model. [ABSTRACT FROM AUTHOR]

Purpose: To study the relationship between liquid nitrogen loss and temperature in cryostorage dewars and develop an early-warning alarm for impending tank failure. Methods: Cryostorage dewars were placed on custom-engineered scales, and weight and temperature data were continuously monitored in the setting of slow, medium, and fast rate-loss of LN2 to simulate three scenarios of tank failure. Results: LN2 Tank weights and temperatures were continuously monitored and recorded, with a calculated alarm trigger set at 10% weight loss and temperature of − 185 °C. With an intact tank, a 10% loss in LN2 occurred in 4.2–4.9 days. Warming to − 185 °C occurred in 37.8–43.7 days, over 30 days after the weight-based alarm was triggered. Full evaporation of LN2 required ~ 36.8 days. For the medium rate-loss simulation, a 10% loss in LN2 occurred in 0.8 h. Warming to − 185 °C occurred in 3.7–4.8 h, approximately 3 h after the weight-based alarm was triggered. For the fast rate-loss simulation, a 10% weight loss occurred within 15 s, and tanks were depleted in under 3 min. Tank temperatures began to rise immediately and at a relatively constant rate of 43.9 °C/h and 51.6 °C/h. Temperature alarms would have sounded within 0.37 and 0.06 h after the breech. Conclusions: This study demonstrates that a weight-based alarm system can detect tank failures prior to a temperature-based system. Weight-based monitoring could serve as a redundant safety mechanism for added protection of cryopreserved reproductive tissues. [ABSTRACT FROM AUTHOR]

Discusses the possibility of mitigating the destructive effects of a thermonuclear explosion by means of materials which absorb light. Information on the forms of destructive energy in a thermonuclear explosion; Dye parameters and results of calculations; Reduction of shock wave and high-energy radiation dosages.

This paper examines the effects of scalar dissipation rate modelling on mean reaction rate predictions in turbulent premixed flames. The sensitivity of the mean reaction rate is explored by using different closures for scalar dissipation and the sensitivity of the scalar dissipation models themselves is also examined with respect to their defining constants. The influence of different scalar dissipation models on the flame location and mean velocities is reported and compared with experimental results. The predicted reaction rate is found to be sensitive to the choice of closure used for scalar dissipation and also to the respective constants used in the scalar dissipation models. It is also found that the scalar dissipation models involving chemical and turbulent time scales yield a more physically plausible reaction rate when compared with the scalar dissipation models relying only on the turbulent time scale. [ABSTRACT FROM AUTHOR]

The accurate resolution of flame structure is critically important to the direct numerical simulation of reacting flows. While grid-resolution estimates are readily available for cold flows, premixed flames appear to have received relatively little attention. In this paper, a premixed flame characterised by single-step chemistry at moderate-to-high Zel'dovitch numbers (β) is analysed, and its structure is used to provide estimates for sufficient grid resolution. It is found that the critical region of the flame exhibits a weak inverse Zel'dovitch number dependence, and that heuristic methods of resolution estimation based on flame thickness grow relatively less meaningful as β → ∞. Resolution estimates for second- and fourth-order finite-difference schemes are provided. [ABSTRACT FROM AUTHOR]

Study Question: What is the prevalence and developmental significance of morphologic nuclear abnormalities in human preimplantation embryos?Summary Answer: Nuclear abnormalities are commonly found in human IVF embryos and are associated with DNA damage, aneuploidy, and decreased developmental potential.What Is Known Already: Early human embryonic development is complicated by genomic errors that occur after fertilization. The appearance of extra-nuclear DNA, which has been observed in IVF, may be a result of such errors. However, the mechanism by which abnormal nuclei form and the impact on DNA integrity and embryonic development is not understood.Study Design, Size, Duration: Cryopreserved human cleavage-stage embryos (n = 150) and cryopreserved blastocysts (n = 105) from clinical IVF cycles performed between 1997 and 2008 were donated for research. Fresh embryos (n = 60) of poor quality that were slated for discard were also used. Immunohistochemical, microscopic and cytogenetic analyses at different developmental stages and morphologic grades were performed.Participants/materials, Setting, Methods: Embryos were fixed and stained for DNA, centromeres, mitotic activity and DNA damage and imaged using confocal microscopy. Rates of abnormal nuclear formation were compared between morphologically normal cleavage-stage embryos, morphologically normal blastocysts, and poor quality embryos. To control for clinical and IVF history of oocytes donors, and quality of frozen embryos within our sample, cleavage-stage embryos (n = 52) were thawed and fixed at different stages of development and then analyzed microscopically. Cleavage-stage embryos (n = 9) were thawed and all blastomeres (n = 62) were disaggregated, imaged and analyzed for karyotype. Correlations were made between microscopic and cytogenetic findings of individual blastomeres and whole embryos.Main Results and the Role Of Chance: The frequency of microscopic nuclear abnormalities was lower in blastocysts (5%; 177/3737 cells) than in cleavage-stage embryos (16%, 103/640 blastomeres, P < 0.05) and highest in arrested embryos (65%; 44/68 blastomeres, P < 0.05). DNA damage was significantly higher in cells with microscopic nuclear abnormalities (γH2AX (phosphorylated (Ser139) histone H2A.X): 87.1%, 74/85; replication protein A: 72.9%, 62/85) relative to cells with normal nuclear morphology (γH2AX: 9.3%, 60/642; RPA: 5.6%, 36/642) (P < 0.05). Blastomeres containing nuclear abnormalities were strongly associated with aneuploidy (Fisher exact test, two-tailed, P < 0.01).Limitations, Reasons For Caution: The embryos used were de-identified, and the clinical and IVF history was unknown.Wider Implications Of the Findings: This study explores a mechanism of abnormal embryonic development post-fertilization. While most of the current data have explored abnormal meiotic chromosome segregation in oocytes as a primary mechanism of reproductive failure, abnormal nuclear formation during early mitotic cell division in IVF embryos also plays a significant role. The detection of abnormal nuclear formation may have clinical application in noninvasive embryo selection during IVF.Study Funding/competing Interests: The study was supported by Columbia University and the New York Stem Cell Foundation. Authors declare no competing interest. [ABSTRACT FROM AUTHOR]

Flame turbulence interactionis an important term for modelling scalar dissipationin premixed turbulent combustion. In order to obtain an accurate representation of the flame turbulence interaction phenomenon, an evolution equation forhas recently been proposed. This equation gives a detailed insight into the flame turbulence interaction phenomenon and provides an alternative approach to modelling the important physics represented by. In this paper theevolution equation is used to model a premixed propane–air flame stabilised in a turbulent mixing layer. The simulations are carried out in the context of a Reynolds Averaged Navier–Stokes (RANS) framework and the results are compared with the experiments and also with Large Eddy Simulation (LES). It is found that the modelling strategy involving theevolution equation gives good approximations for the mean velocities and flame locations in the mixing layer stabilised flame when compared with other modelling strategies. [ABSTRACT FROM AUTHOR]

Flame turbulence interaction is one of the leading order terms in the scalar dissipation $\left (\widetilde {\varepsilon }_{c}\right )$ transport equation [] and is thus an important phenomenon in premixed turbulent combustion. Swaminathan and Grout [] and Chakraborty and Swaminathan [, ] have shown that the effect of strain rate on the transport of $\widetilde {\varepsilon }_{c}$ is dominated by the interaction between the fluctuating scalar gradients and the fluctuating strain rate, denoted here by $\overline {\rho }\widetilde {\Delta }_{c}= \overline {\rho {\alpha }\nabla c^{\prime \prime }S_{ij}^{\prime \prime }\nabla c^{\prime \prime }}$; this represents the flame turbulence interaction. In order to obtain an accurate representation of this phenomenon, a new evolution equation for $\widetilde {\Delta }_{c}$ has been proposed. This equation gives a detailed insight into flame turbulence interaction and provides an alternative approach to model the important physics represented by $\widetilde {\Delta }_{c}$. The $\widetilde {\Delta }_{c}$ evolution equation is derived in detail and an order of magnitude analysis is carried out to determine the leading order terms in the $\widetilde {\Delta }_{c}$ evolution equation. The leading order terms are then studied using a Direct Numerical Simulation (DNS) of premixed turbulent flames in the corrugated flamelet regime. It is found that the behaviour of $\widetilde {\Delta }_{c}$ is determined by the competition between the source terms (pressure gradient and the reaction rate), diffusion/dissipation processes, turbulent strain rate and the dilatation rate. Closures for the leading order terms in $\widetilde {\Delta }_{c}$ evolution equation have been proposed and compared with the DNS data. [ABSTRACT FROM AUTHOR]

The transfer of somatic cell nuclei into oocytes can give rise to pluripotent stem cells that are consistently equivalent to embryonic stem cells, holding promise for autologous cell replacement therapy. Although methods to induce pluripotent stem cells from somatic cells by transcription factors are widely used in basic research, numerous differences between induced pluripotent stem cells and embryonic stem cells have been reported, potentially affecting their clinical use. Because of the therapeutic potential of diploid embryonic stem-cell lines derived from adult cells of diseased human subjects, we have systematically investigated the parameters affecting efficiency of blastocyst development and stem-cell derivation. Here we show that improvements to the oocyte activation protocol, including the use of both kinase and translation inhibitors, and cell culture in the presence of histone deacetylase inhibitors, promote development to the blastocyst stage. Developmental efficiency varied between oocyte donors, and was inversely related to the number of days of hormonal stimulation required for oocyte maturation, whereas the daily dose of gonadotropin or the total number of metaphase II oocytes retrieved did not affect developmental outcome. Because the use of concentrated Sendai virus for cell fusion induced an increase in intracellular calcium concentration, causing premature oocyte activation, we used diluted Sendai virus in calcium-free medium. Using this modified nuclear transfer protocol, we derived diploid pluripotent stem-cell lines from somatic cells of a newborn and, for the first time, an adult, a female with type 1 diabetes. [ABSTRACT FROM AUTHOR]

In this paper, a one dimensional premixed laminar methane flame is subjected to acoustic oscillations and studied. The purpose of this analysis is to investigate the effects of acoustic perturbations on the reaction rates of different species, with a view to their respective contribution to thermoacoustic instabilities. Acoustically transparent non reflecting boundary conditions are employed. The flame response has been studied with acoustic waves of different frequencies and amplitudes. The integral values of the reaction rates, the burning velocities and the heat release of the acoustically perturbed flame are compared with the unperturbed case. We found that the flame's sensitivity to acoustic perturbations is greatest when the wavelength is comparable to the flame thickness. Even in this case, the perturbations are stable with time. We conclude that acoustic fields acting on the chemistry do not contribute significantly to the emergence of large amplitude pressure oscillations. [ABSTRACT FROM AUTHOR]

Mitochondrial DNA mutations transmitted maternally within the oocyte cytoplasm often cause life-threatening disorders. Here we explore the use of nuclear genome transfer between unfertilized oocytes of two donors to prevent the transmission of mitochondrial mutations. Nuclear genome transfer did not reduce developmental efficiency to the blastocyst stage, and genome integrity was maintained provided that spontaneous oocyte activation was avoided through the transfer of incompletely assembled spindle-chromosome complexes. Mitochondrial DNA transferred with the nuclear genome was initially detected at levels below 1%, decreasing in blastocysts and stem-cell lines to undetectable levels, and remained undetectable after passaging for more than one year, clonal expansion, differentiation into neurons, cardiomyocytes or ?-cells, and after cellular reprogramming. Stem cells and differentiated cells had mitochondrial respiratory chain enzyme activities and oxygen consumption rates indistinguishable from controls. These results demonstrate the potential of nuclear genome transfer to prevent the transmission of mitochondrial disorders in humans. [ABSTRACT FROM AUTHOR]

The exchange of the oocyte's genome with the genome of a somatic cell, followed by the derivation of pluripotent stem cells, could enable the generation of specific cells affected in degenerative human diseases. Such cells, carrying the patient's genome, might be useful for cell replacement. Here we report that the development of human oocytes after genome exchange arrests at late cleavage stages in association with transcriptional abnormalities. In contrast, if the oocyte genome is not removed and the somatic cell genome is merely added, the resultant triploid cells develop to the blastocyst stage. Stem cell lines derived from these blastocysts differentiate into cell types of all three germ layers, and a pluripotent gene expression program is established on the genome derived from the somatic cell. This result demonstrates the feasibility of reprogramming human cells using oocytes and identifies removal of the oocyte genome as the primary cause of developmental failure after genome exchange. [ABSTRACT FROM AUTHOR]

In this paper, we develop a method of prescribing time dependent boundary conditions for reacting flows. The method builds on earlier results, and derives from a linearization of the flow field around a base state. The base state is specified in terms of the flow dilatation, and we establish a general expression for the dilatation in reacting flows at low Mach number. This expression is then used to derive acoustically transparent boundary conditions. The utility of the approach is demonstrated via a number of laminar flame calculations, ranging in complexity from single step chemistry to a multi-step methane mechanism. The accuracy of the resulting solutions is found to be superior to those obtained using other means. [ABSTRACT FROM AUTHOR]

The flow around a trailing edge is computed with a new hybrid method designed to more clearly separate the effects of total and sub-grid turbulent stress-modelling on the time-averaged and instantaneous velocity fields, and in turn, mean momentum and kinetic energy balances. These two velocity fields independently define Reynolds averaged and sub-grid-scale viscosities, and distinct stresses, at the same location. In particular, resolved eddies can emerge, or sweep in and out of the Reynolds averaged near wall layer, without being dampened by higher levels of the viscosity in this RANS dominated layer. The two-field hybrid model, first tested on channel flows, gives accurate predictions of mean velocities and stresses for different Reynolds numbers and coarse meshes. For the trailing edge flow the results of the hybrid model are close to the reference fine LES for mean velocity and turbulent content, whereas the DES-SST on the same coarse mesh gives too early separation. [ABSTRACT FROM AUTHOR]

Objective. Compare the prevalence of comorbidities in adults with and without asthma in Canada and investigate the association between comorbidities in patients with asthma and the occurrence of asthma symptoms or attacks. Methods. Survey data from the 2005 Canadian Community Health Survey (CCHS) were analyzed. A total of 132,221 Canadians participated in the national survey; 10,089 adult respondents from 10 Canadian provinces and 3 territories reported having asthma. Analyses focused on 11 major chronic comorbidities. Results. Respondents with asthma were more likely to have comorbidities except cancer; 31% of respondents with asthma and comorbidities reported their health status to be fair or poor. For respondents with asthma, non-asthma chronic respiratory disease, mental illness, and allergy were significantly associated with having asthma symptoms or attacks. Conclusions. Many Canadians with asthma report a high comorbidity burden. These patients will likely require more health services and more complex health management strategies. Comorbid conditions should be clearly identified with particular emphasis on management of mood disorders and anxiety because these conditions are likely to increase asthma symptomatology and may be unrecognized by clinicians. [ABSTRACT FROM AUTHOR]

Purpose To identify risk factors for suboptimal IVF outcomes using insemination with donor spermatozoa and to define a lower threshold that may signal a conversion to fertilization by ICSI rather than insemination. Method Retrospective, age-matched, case-control study of women undergoing non-donor oocyte IVF cycles using either freshly ejaculated (N=138) or cryopreserved donor spermatozoa (N=69). Associations between method of fertilization, semen sample parameters, and pregnancy rates were analyzed. Results In vitro fertilization of oocytes with donor spermatozoa by insemination results in equivalent fertilization and pregnancy rates compared to those of freshly ejaculated spermatozoa from men with normal semen analyses when the post-processing motility is greater than or equal to 88%. IVF by insemination with donor spermatozoa when the post-processing motility is less than 88% is associated with a 5-fold reduction in pregnancy rates when compared to those of donor spermatozoa above this motility threshold. When the post-processing donor spermatozoa motility is low, fertilization by ICSI is associated with significantly higher pregnancy rates compared to those of insemination. Conclusion While ICSI does not need to be categorically instituted when using donor spermatozoa in IVF, patients should be counseled that conversion from insemination to ICSI may be recommended based on low post-processing motility. [ABSTRACT FROM AUTHOR]

Objective. To develop a parsimonious model of the respiratory patient population in British Columbia (BC), Canada through latent class modelling (LCM), using administrative data records and to assess conventional case definitions for asthma in relation to model-based case selection. Data Sources. 1996–2001 data from linked provincial databases containing fee-for-service physician billing records, hospital inpatient separation abstracts, and prescription drug purchase records for 1.9 million BC respiratory patients. Study Design. This is a retrospective methodological/descriptive study that assesses case definitions for asthma in terms of sensitivity and specificity using a model fitted to seven physician, hospital and medication utilization markers in place of a conventional gold standard. Data Collection. We computed values of the treatment markers for each of the 5 years for each patient aged 5–55 years who had had at least one occurrence of a respiratory diagnosis code. Principal Findings. The marker for prescription of short-acting β agonists (SABAs) consistently had the highest sensitivity. Markers' specificities ranged from 0.97 to 1.0. The conventional case definitions' sensitivities were 0.41–0.87; specificities ranged from 0.98 to 0.997. Model-based estimates of asthma prevalence increased from 827/10,000 in 1996 to 992/10,000 in 2001. Conventional case definitions' estimates were consistently lower. Conclusions. The linkage between utilization and case status is more complex than conventional case definitions allow for. LCM-based case classification was consistent over time and tends to lead to larger prevalence estimates than conventional definitions. The estimated increases in asthma prevalence are reliable. LCM provides health services planners with a useful probability-based approach for developing and assessing case definitions and estimating case prevalence. [ABSTRACT FROM AUTHOR]

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This report explores the possibility that heat plays a role in the penetration of cloth ballistic panels by 0.22 caliber projectiles. We postulate that heat is generated by friction between the surface of the projectile and the yarns, between yarns, and between filaments within a yarn in advance of and in the path of the projectile. Evaluations by light microscopy, polarized light microscopy, and scanning electron microscopy show heat- induced damage in fibers in the path of and several layers preceding the layer at which a 0.22 caliber projectile comes to rest. Polarization microscopy of impacted yarns reveals differences in birefringence within the fibers close to the hole made by the projectile compared with the same fiber at a greater distance from the hole. Heat is an energy sink, and depending on how, when, and where it is generated, can degrade the ballistic performance of the yarns. The quantitative importance of heat in affecting ballistic panel performance is elusive: consequently, the discussion presented here is largely qualitative. [ABSTRACT FROM PUBLISHER]

The objectives of this review were to assess the quality of articles published in JES, to find out whether or not JES is perceived to occupy a distinct niche among the quantitative journals that serve educational research, and to obtain suggestions for improvement. These objectives were addressed by one or another of the five components to the review: an assessment by experts, a questionnaire survey, a citation study, a content analysis of the articles in selected volumes of JES, and a study of keywords. The accumulated evidence indicates that JES is seen to publish good quality articles that make original contributions to knowledge. The questionable relevance of some articles to the study of education and the emphasis in some articles on measurement issues perhaps reflects the fact that the niche occupied by JES is not wholly congruent with the objective stated on the journal's boilerplate. Suggestions are offered for ways of increasing the number of appropriate articles and increasing circulation. [ABSTRACT FROM PUBLISHER]

This paper describes a project in the School of Chemistry at The University of Melbourne. During 1992 thirty hours of videotapes were taken of students doing quantitative volumetric work in first year laboratories. These were viewed to find out what problems students encountered and what interactions they had with other students and with demonstrators. The data were logged on a Hypercard stack and novel visual images were produced to map student activity, both qualitatively and quantitatively. These data contributed to the design of a multimedia learning package which students worked through at the beginning of 1993. Video data of their laboratory performance after this intervention provides evidence of improved performance. [ABSTRACT FROM AUTHOR]

Studies the adverse effect of norethindrone acetate (NETA) to leuprolide acetate (LA) on controlled ovarian stimulation during in vitro fertilization. Absence of adverse effect on ovarian stimulation on the addition of NETA to LA; Non-observance of differences in the days of stimulation, peak estradiol level attained and other factors.