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Nucleation is an out-of-equilibrium process that can be strongly affected by the presence of external fields. In this paper, we report a simple extension of classical nucleation theory to systems submitted to an homogeneous shear flow. The theory involves accounting for the anisotropy of the critical nucleus formation and introduces a shear-rate-dependent effective temperature. This extended theory is used to analyze the results of extensive molecular dynamics simulations that explore a broad range of shear rates and undercoolings. At fixed temperature, a maximum in the nucleation rate is observed, when the relaxation time of the system is comparable to the inverse shear rate. In contrast to previous studies, our approach does not require a modification of the thermodynamic description, as the effect of shear is mainly embodied into a modification of the kinetic prefactor and of the temperature. © 2013 American Physical Society.

In a series of 818 patients treated with indomethacin during pregnancy, the rate of perinatal complications was 1.8%. The risk was increased to 13% if indomethacin was being taken at the time of delivery, and when treatment was prolonged. The serious nature of certain complications (persistence of fetal circulation and oligo/anuria) means that indomethacin should only be used in cases in which betamimetic drugs are formally contraindicated or if there is a risk of unacceptable prematurity. Even in such cases, indomethacin should only be given for short period (1 week).

Nonequilibrium atomic dynamics is simulated in single-component metallic glass under the influence of shear strains with different shear rates and temperatures. Based on the simulation data and cluster analysis, such parameters of nucleation processes as the nucleation rate, the size of a critical cluster, and the Zeldovich factor are found. The dependence of these quantities on the shear rate is discussed. © 2011 Allerton Press, Inc.

Objective : The purpose of the study is to assess the efficacy of and adverse events linked to the use of intravenous sulprostone during the 2nd or 3rd trimesters of pregnancy for therapeutic abortion. Study design : One hundred eighty-two patients (70 nulliparous, 112 multiparous) were hospitalized for therapeutic abortion. The route of administration was invariably intravenous and one single dose of sulprostone was used: 1000 μg of sulprostone diluted in 11 of isotonic saline solution given as a 10-h infusion. Result : Expulsion within the first 24 h was obtained in 70% of cases with a mean induction-expulsion interval of 14 h. In three cases, laparotomy was required for hemorrhagic syndromes. Conclusion : Intravenous sulprostone enable evacuation of uterine contents with minimal adverse reaction. Attention should nevertheless be drawn to the existence of hemorrhagic syndromes.

A preliminary study in 22 patients with uterine scarring was undertaken using sulprostone by intravenous infusion when therapeutic abortion was deemed necessary during the 2nd and 3rd trimesters of pregnancy. The dosage used was 500 μg by slow infusion lasting 10 h. There were no cases of ruptured uterus. Adverse reactions were absent. Results were satisfactory. Mean induction-expulsion duration: 11 h. Expulsion rate in 24 h: 63%. With strict monitoring and in a specialized center, this technique may be suggested when a late therapeutic abortion with a scarred uterus is indicated.

Crystal nucleation and growth processes induced by an externally applied shear strain in a model metallic glass are studied by means of nonequilibrium molecular dynamics simulations, in a range of temperatures. We observe that the nucleation-growth process takes place after a transient, induction regime. The critical cluster size and the lag-time associated with this induction period are determined from a mean first-passage time analysis. The laws that describe the cluster-growth process are studied as a function of temperature and strain rate. A theoretical model for crystallization kinetics that includes the time dependence for nucleation and cluster growth is developed within the framework of the Kolmogorov-Johnson-Mehl-Avrami scenario and is compared with the molecular dynamics data. Scalings for the cluster-growth laws and for the crystallization kinetics are also proposed and tested. The observed nucleation rates are found to display a nonmonotonic strain rate dependency. © 2010 The American Physical Society.

Nonequilibrium molecular dynamics simulations of a model amorphous system are performed with the aim of studying the structural transformations induced by external shear influence. We reveal that the shear drive has both positive and negative effects on the structural ordering processes. The dependence of the phase transition rate versus the strain rate at three different temperatures is found. © 2010 Allerton Press, Inc.

Although vaginal ultrasonography combined with plasma beta-hCG determination can provide a reliable diagnosis and location of ectopic pregnancy, the results can be difficult to interpret in the early stages when hCG levels are low. Hysteroscopy can be used in such cases to differentiate between ectopic pregnancy and non-viable uterine pregnancy when viable uterine pregnancy has been ruled out. General anaesthesia and laparoscopy are avoided. We performed 60 hysteroscopic procedures between January 1989 and December 1990 in patients with suspected ectopic pregnancies. The pregnancy had been located by means of vaginal ultrasonography in every case in which the hCG was above 1500 IU/ml and in 36% of cases in which the beta-hCG was below this level. Hysteroscopy was hindered by metrorrhagia in three cases and was inconclusive in one, necessitating laparoscopy. Diagnosis was possible in all the remaining cases, as follows: ectopic pregnancy in 41 cases, with an empty uterus and occasional bleeding from an ostium; non-viable uterine pregnancy in 18 cases, with the presence of material within the cavity. Hysteroscopy therefore confirmed the diagnosis in 55% of the cases and was itself diagnostic in a further 43% of cases. Its sensitivity for the diagnosis of ectopic pregnancy was 100% and its specificity 95%. We propose a diagnostic decision tree.

We report the case of a dichorionic and diamniotic pregnancy with the unique feature of an early ultrasound diagnosis of a 4-week size difference, which persisted throughout pregnancy. At birth, the twins had a 1-month difference in physical and neurological maturity. We believe that only the phenomenon of a superfetation can explain this difference. We report the cases found in the literature. Copyright © 1992 International Society of Ultrasound in Obstetrics and Gynecology

40 patients with advanced ovarian cancer were treated with immediate debulking followed by sequential cisplatin and doxorubicin every 4 weeks, followed by second-look laparotomy (SLL). Six courses were given when residual disease (RD) was under 2 cm. When RD was over 2 cm, three courses were followed by early debulking and six more courses before SLL. Immediate debulking was optimal in 15 patients (38%) and early debulking in an additional 15 (38%). Pathological complete responses (34 evaluable cases) were observed in 14 cases (41%), partial response in 13 (38%), stable disease in 3 (9%) and progression in 5 (15%). Toxicity was mainly haematological. 11 patients with negative SLL and 15 with RD under 2 cm received intraperitoneal cisplatin 200 mg/m2 alone or with cytarabine. Median survival was 45 months: 58 months for RD under 2 cm at initial laparotomy and 31 months for RD over 2 cm. Median survival was 46 months when early debulking was successful. 5 year disease-free survival was only 16%. However, this multimodal treatment offers prolonged survival, especially in patients optimally debulked either at initial laparotomy or at early debulking surgery.

We report results of nonequilibrium molecular dynamics simulations of a one-component glassy system under the influence of a shear flow, with the aim of investigating shear-induced ordering of this system. In spite of the very low temperature, the system transforms into a strained crystalline state through well defined nucleation events. Various characteristics of the observed ordering at different strain rates and temperatures are discussed. We also define and discuss the transition rates. © 2009 American Institute of Physics.

By modification of the circulating pool of biliary acids, the administration of ursodesoxycholic acid has permitted the restoration of normal maternal hepatic function during a triple pregnancy complicated by the precocious onset of an intrahepatic cholestasis. The marked regression in clinical and biological markers of the disease confirms the role of biliary acids in the aggravation of hepatic abnormalities.

The linear response of two-dimensional amorphous elastic bodies to an external delta force is determined in analogy with recent experiments on granular aggregates. For the generated forces, stress and displacement fields, we find strong relative fluctuations of order one close to the source, which, however, average out readily to the classical predictions of isotropic continuum elasticity. The stress fluctuations decay (essentially) exponentially with distance from the source. Only beyond a surprisingly large distance, $b \approx 30$ interatomic distances, self-averaging dominates, and the quenched disorder becomes irrelevant for the response of an individual configuration. We argue that this self-averaging length $b$ sets also the lower wavelength bound for the applicability of classical eigenfrequency calculations.Particular attention is paid to the displacements of the source, allowing a direct measurement of the local rigidity. The algebraic correlations of these displacements demonstrate the existence of domains of slightly different rigidity without, however, revealing a characteristic length scale, at least not for the system sizes we are able to probe., Comment: 27 pages, 10 figures

Theoretical calculations are performed to study transformations in silica as a function of nonhydrostatic stress. Molecular-dynamics calculations reveal a crystalline-to-crystalline transition from alpha-quartz to a phase with five-coordinated silicon (Si-V) at high pressure in the presence of deviatoric stress. The phase, which appears for specific orientations of the stress tensor relative to the crystallographic axes of quartz, is a crystalline polymorph of silica with five-coordinated silicon. The structure possesses P3(2)21 space-group symmetry. First-principles calculations within the local-density approximation, as well as molecular dynamics and energy minimization with interatomic potentials, find this phase to be mechanically and energetically stable with respect to quartz at high pressure. The calculated x-ray diffraction pattern and vibrational properties of the phase are reported. Upon decompression, the Si-V phase reverts to alpha-quartz through an intermediate four-coordinated phase and an unusual isosymmetrical phase transformation. The results suggest the importance of application of nonhydrostatic stress conditions in the design and synthesis of novel materials. NSF

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