Assessment of a High-Throughput Methodology for the Study of Alloy Oxidation using AlxFeyNi1-x-y Composition Gradient Thin Films.

The high-temperature oxidation of multicomponent metal alloys exhibits complex dependencies on composition, which are not fully understood for many systems. Combinatorial screening of the oxidation of many different compositions of a given alloy offers an ideal means for gaining fundamental insights into such systems. We have previously developed a high-throughput methodology for studying AlxFeyNi1-x-y alloy oxidation using ∼100 nm thick composition spread alloy films (CSAFs). In this work, we critically assess two aspects of this methodology: the sensitivity of CSAF oxidation behavior to variations in AlxFeyNi1-x-y composition and the differences between the oxidation behavior of ∼100 nm thick CSAFs and that of bulk AlxFeyNi1-x-y alloys. This was done by focusing specifically on AlxFe1-x and AlxNi1-x oxidation in dry air at 427 °C. Transitions between phenomenologically distinguishable types of oxidation behavior are found to occur over CSAF compositional ranges of <2 at. %. The oxidation of AlxFe1-x CSAFs is found to be very similar to that of bulk AlxFe1-x alloys, but some minor differences between CSAF and bulk behavior are observed for AlxNi1-x oxidation. On the basis of our assessment, high-throughput studies of CSAF oxidation appear to be an effective method for gaining fundamental insights into the composition dependence of the oxidation of bulk alloys.

On the Structural and Chemical Characteristics of Co/Al2O3/graphene Interfaces for Graphene Spintronic Devices.

We report a detailed investigation of the structural and chemical characteristics of thin evaporated Al2O3 tunnel barriers of variable thickness grown onto single-layer graphene sheets. Advanced electron microscopy and spectrum-imaging techniques were used to investigate the Co/Al2O3/graphene/SiO2 interfaces. Direct observation of pinhole contacts was achieved using FIB cross-sectional lamellas. Spatially resolved EDX spectrum profiles confirmed the presence of direct point contacts between the Co layer and the graphene. The high surface diffusion properties of graphene led to cluster-like Al2O3 film growth, limiting the minimal possible thickness for complete barrier coverage onto graphene surfaces using standard Al evaporation methods. The results indicate a minimum thickness of nominally 3 nm Al2O3, resulting in a 0.6 nm rms rough film with a maximum thickness reaching 5 nm.

All-Diamond Microelectrodes as Solid State Probes for Localized Electrochemical Sensing.

The fabrication of an all-diamond microprobe is demonstrated for the first time. This ME (microelectrode) assembly consists of an inner boron doped diamond (BDD) layer and an outer undoped diamond layer. Both layers were grown on a sharp tungsten tip by chemical vapor deposition (CVD) in a stepwise manner within a single deposition run. BDD is a material with proven potential as an electrochemical sensor. Undoped CVD diamond is an insulating material with superior chemical stability in comparison to conventional insulators. Focused ion beam (FIB) cutting of the apex of the ME was used to expose an electroactive BDD disk. By cyclic voltammetry, the redox reaction of ferrocenemethanol was shown to take place at the BDD microdisk surface. In order to ensure that the outer layer was nonelectrically conductive, a diffusion barrier for boron atoms was established seeking the formation of boron-hydrogen complexes at the interface between the doped and the undoped diamond layers. The applicability of the microelectrodes in localized corrosion was demonstrated by scanning amperometric measurements of oxygen distribution above an Al-Cu-CFRP (Carbon Fiber Reinforced Polymer) galvanic corrosion cell.

Ovarian consequences of the transient interruption of combined oral contraceptives.

The combined oral contraceptive pill is an efficient means of contraception. It acts at different levels of the genital tract. Despite its efficiency, it is universally suggested that patients take the pill at regular daily intervals. Little attention has been given to the question of what happens if you miss the pill one day or more. A study was undertaken to evaluate the consequences of pill misses at different times of the cycle. Forty-seven young, healthy, normally menstruating patients voluntarily enrolled. All were given Cilest (ethinyl estradiol 35 micrograms and norgestimate 250 mg, Cilag France) for 21 days without any misses. Then, after a 7-day interval, they were prescribed one (group 1), two (group 2), three (group 3) or four days of pill misses, to occur respectively on day 1 (group a), 6 (group b), 12 (group c) or 18 (group d) of a new 21 day cycle; supplementary contraceptive means were recommended. Four patients had no miss prescribed and served as controls. Ovarian function was evaluated with daily estrogen measurements (E1 + E2 enzymatic dosage, BioMérieux, France) and ultrasound examinations. When required, because of significant increase in estrogen or because of follicular growth detected on ultrasound, LH and progesterone were measured. None of the patients experienced a normal ovulation. Four patients (1 control, 1 from group 2a, and 2 from group 3a) had a significant increase in estrogen levels and had a follicular image on ultrasounds. One of them (group 3a) had a follicular rupture, but none had a LH surge or increase in progesterone.(ABSTRACT TRUNCATED AT 250 WORDS)

[Ovarian suppressive activity of a low dose monophasic oral contraceptive during correct and incorrect pill intake]. / Etude de l'activite contraceptive d'une pilule minidosee lors de son utilisation correcte ou incorrecte.

PIP: A systematic study was undertaken in order to evaluate the consequences of missing oral contraceptives (OCs) at different times in the cycle. 39 young, healthy, normally menstruating patients were voluntarily enrolled in this study and all were given Cilest (ethinyl estradiol 35 mcg + norgestimate 250 mcg, Cilag, France) for 21 days without any gaps. Then, after a 7-day interval, they were prescribed 1 (group 1), 2 (group 2), 3 (group 3), or 4 (group 4) days of OC misses. These occurred on day 1 (class a), day 6 (class b), day 12 (class c), or day 18 (class d) of a 21 day Cilest cycle. In addition, supplementary contraceptive measures were recommended to those participating. With 47 cycles examined, 5 patients had no miss prescribed and this group served as the controls. Ovarian function was evaluated with daily estrogen monitoring (E1 + E2 enzymatic dosage, Bio Merieux, France) and ultrasound examination. When necessary, due to a significant estrogen increase or follicular growth detected on ultrasound, progesterone and LH were measured. 9 patients showed a follicular image on ultrasound. 4 patients (1 control, 3 others ) had a significant increase in estrogens and 2 others had no secretions. All the others had no manifestation of restoration of ovarian function. None of the 9 patients had a normal ovulation (no LH surge or increase in progesterone). Blockage of ovarian function by OCs remains efficient even after several days of OC missing. (author's modified)^ieng

Ovarian consequences of the transient interruption of combined oral contraceptives.

The combined oral contraceptive pill is an efficient means of contraception. It acts at different levels of the genital tract. Despite its efficiency, it is universally suggested that patients take the pill at regular daily intervals. Little attention has been given to the question of what happens if you miss the pill one day or more. A study was undertaken to evaluate the consequences of pill misses at different times of the cycle. Forty-seven young, healthy, normally menstruating patients voluntarily enrolled. All were given Cilest (ethinyl estradiol 35 micrograms and norgestimate 250 mg, Cilag France) for 21 days without any misses. Then, after a 7-day interval, they were prescribed one (group 1), two (group 2), three (group 3) or four days of pill misses, to occur respectively on day 1 (group a), 6 (group b), 12 (group c) or 18 (group d) of a new 21 day cycle; supplementary contraceptive means were recommended. Four patients had no miss prescribed and served as controls. Ovarian function was evaluated with daily estrogen measurements (E1 + E2 enzymatic dosage, BioMérieux, France) and ultrasound examinations. When required, because of significant increase in estrogen or because of follicular growth detected on ultrasound, LH and progesterone were measured. None of the patients experienced a normal ovulation. Four patients (1 control, 1 from group 2a, and 2 from group 3a) had a significant increase in estrogen levels and had a follicular image on ultrasounds. One of them (group 3a) had a follicular rupture, but none had a LH surge or increase in progesterone.(ABSTRACT TRUNCATED AT 250 WORDS)

Early or late monitoring of stimulation of ovulation for in-vitro fertilization? A methodological discussion of a randomized study.

Two GnRH agonist long-stimulation protocols, in association with HMG, are compared on a random basis. Group A (n = 53) was monitored daily from the 6th day of stimulation, whereas monitoring in group B (n = 55) began on the 11th day of stimulation. There was no significant difference in the numbers of follicles which matured, the numbers of collected oocytes, the numbers of embryos obtained in vitro and the clinical pregnancy rate. But the power of such a study is very weak (6%). It would have been necessary to include greater than 1000 patients in each group to obtain a bioequivalence test. Such a study is unrealistic for a single centre and multicentric studies are very difficult to achieve because of practical difficulties. A pooled analysis is perhaps the methodological answer.

[Use of a technic of bioluminescence for determining estrogens and LH during static and dynamic study of the ovary]. / Utilisation d'une technique de bioluminescence pour le dosage des estrogènes et de la LH lors de l'exploration statique et dynamique de l'ovaire.

Estrogens and LH are necessary among other assays for ovulation diagnostic and ovarian monitoring during stimulations. They can be both measured with a method based on a bioluminescent reaction. This method measures, with a standard luminometer, the reduced NAD produced and accumulated by the reaction of two dehydrogenase enzymes: the estradiol dehydrogenase for direct assay of estrogens (estrone + estradiol), the glucose-6-phosphate dehydrogenase for gonadotrophin determination. These techniques can be applied to all biological fluids. They are simple and straightforward, do not need extraction and can be automated. Urinary assays are very useful in clinical practice to appreciate ovarian function, either during a spontaneous cycle or under stimulation, and are mandatory to decide the timing of hCG injection. The reported studies can be listed as follows: determination of preovulatory LH rise (LH greater than 10 Ul/g of creatinine) prior to embryo transfer after cryopreservation and thawing, detection of LH surges during ovarian stimulation, either premature surges causing premature luteinization, either normal surges when follicular maturation is adequate (296 cycles), confirmation of pituitary desensitization when using GnRH agonists (43 cycles), study of the initial stimulatory effect of GnRH agonists (13 patients). This effect can be responsible for the inadequate results obtained with the so-called "short protocol" in this experience when compared with the "long protocol" in the author's experience with compared with the "long protocol" (8 p. cent pregnancy rate per stimulation cycle versus 20 p. cent respectively, intrafollicular LH in 129 follicular fluids (86 with GnRH agonists and 43 without) has no correlation with the fecundability of the ovum. These results lead to extend bioluminescent techniques to the study of other parameters, and in particular FSH.

[Bioluminescence assay of luteinizing hormone in plasma and urine]. / Dosage par bioluminescence de l'hormone lutéinisante dans le plasma et l'urine.

The authors describe a bioluminescent immunoassay of LH in plasma and urine. It uses two monoclonal antibodies, one is labelled with glucose-6-phosphate-dehydrogenase, the other one is coimmobilized together with bioluminescent enzymes from marine bacteria on the same adsorbent (Sepharose). This assay can be performed directly on 20 microliters plasma or 10 microliters urine. The protocol is very fast, no separation step is required to remove the excess labeled antibodies. The inhibitory effect of the biological sample on luminescent reaction is determined by adding NADH to the assay tubes. The working range of this assay is 3 to 300 Ul/l, with a sensitivity of detection of 0.5 Ul/l. Recovery, linearity, within and between assay precision were evaluated and appeared to be satisfactory. The authors have observed a good correlation between results obtained with our method and with radioimmunoassay.

Correlations between free plasma estradiol and estrogens determined by bioluminescence in saliva, plasma, and urine during spontaneous and FSH stimulated cycles in women.

Estrone and estradiol (E1 + E2) concentrations in saliva were compared with four other parameters of estrogen status in five normal ovulatory women and ten FSH stimulated women selected for an in vitro fertilization program. E1 + E2 in saliva, plasma, and urine were assessed by a rapid, specific and sensitive enzymatic assay using bioluminescence. The free fraction of plasma estradiol was determined by equilibrium dialysis and total plasma estradiol by conventional radioimmunoassay. The pattern of E1 + E2 variation in saliva was similar to that of free plasma estradiol and the two parameters were correlated in both spontaneous and stimulated cycles. However, the lower correlation coefficient (r = 0.52, P less than 0.001) in spontaneous cycles compared with the high (r = 0.96, P less than 0.001) in the stimulated cycles shows that salivary E1 + E2 could be representative of plasma free estradiol in stimulated cycles but not in normal cycles. The free fraction of plasma estradiol reproduced the variation of total plasma estradiol in spontaneous as well as in FSH stimulated cycles and both parameters were strongly correlated (r = 0.91, P less than 0.001 and r = 0.90, P less than 0.001), respectively. The data show that salivary E1 + E2 concentrations are highly representative of the free fraction of E2 in plasma and at a lesser extend (r = 0.72, P less than 0.001) of total plasma E2 in FSH stimulated cycles.

Ovarian stimulation by a combination of a gonadotropin-releasing hormone agonist and gonadotropins for in vitro fertilization.

In the first of two studies, 20 patients were selected on the basis of tubal infertility and were randomly assigned to two groups receiving different ovarian stimulation protocols. In group A, 10 patients were given follicle-stimulating hormone (FSH), FSH was continued until the criteria for human chorionic gonadotropin (hCG) administration were satisfied. In group B, 10 patients received Buserelin (0.3 ml twice a day subcutaneously) for 14 days to induce pituitary desensitization. Stimulation with FSH was then started, and Buserelin treatment was continued until hCG administration. In the second study, patients were included if they had had at least two previous attempts at ovarian stimulation that failed to reach the stage of follicular aspiration. Ovarian stimulation was conducted with a combination of Buserelin and human menopausal gonadotropin. Use of the gonadotropin-releasing hormone (GnRH) agonist in in vitro fertilization increased the number of oocytes collected, the fertilization rate, the length of the luteal phase and the pregnancy rate. The GnRH agonist also contributed to a generally better ovarian response in patients whose estradiol production had previously responded poorly to conventional ovarian stimulation protocols.

[Action of Parlodel on the preovulatory peak of estrogens and the ovulatory response of patients with abnormal ovulation and normal blood prolactin]. / Etude de l'action du Parlodel sur le pic préovulatoire d'estrogènes et la réponse ovulatoire des patientes ayant une anomalie de l'ovulation avec normoprolactinémie.

Bromocriptine, a dopamine agonist, is well known for its inhibitory action on prolactin secretion. Its action on other hypophyseal secretions, particularly on the gonadotrophins FSH and LH can indicate use of Parlodel as a stimulatory agent for induction of ovulation even in cases of normal prolactinemia. 129 normoprolactinemic patients with a defect of the preovulatory estrogen rise have been treated over a period of 3 months. 63% of the patients exhibited a positive response to bromocriptine, either because a pregnancy started or because preovulatory E1+E2 became normal. The rate of "responders" is increased among those patients who had conservation of spontaneous menses at the start of therapy. Conclusions of the study are that Parlodel has a place among treatments of ovulation defects. Its genuine efficacity must be confirmed by a controlled study against placebo and other confirmed treatments like antiestrogens.

Follicular steroids in relation to oocyte development and human ovarian stimulation protocols.

Oocytes of pre-ovulatory follicles were collected by laparoscopy for in-vitro fertilization in 118 women. Patients were treated either during the natural cycle, or after induction of ovulation with clomiphene citrate, or with human menopausal gonadotrophin (HMG), or clomiphene citrate combined with HMG. The oestrogens (oestrone + oestradiol) and total aromatizable androgens (androstenedione, testosterone and dehydroepiandrosterone and its sulphate) were assayed in follicular fluids using an enzymatic method. The levels of progesterone, 17 alpha OH-progesterone, thromboxane, and prostaglandins (PGE2 and PGF2 alpha) were determined by radioimmunoassay. The best follicular fluid indicator of oocyte fertilization in vitro was the A/E ratio, which was less than 1 when the oocyte was fertilized in vitro and led to a pregnancy. The lowest value for the A/E ratio was obtained with spontaneous ovulation protocols. Regardless of oocyte development, the progesterone level was always greater than 2000 ng/ml, and the PGE2/PGF2 alpha ratio was greater than 1 in all stimulated cycles. Our investigations show that a combination of clomiphene citrate and HMG provides the best stimulation, on the basis of follicular fluid analysis and the outcome of fertilized oocytes.

[Stimulation of ovulation by pure FSH for in vitro fertilization. Study of the route of administration]. / Stimulation de l'ovulation par la FSH pure en vue de fécondation in vitro. Etude de la voie d'administration.

Pulsatile injection of FSH to stimulate ovulation for in vitro fertilization was undertaken in order to compare the intramuscular route with the pulsatile subcutaneous route in two groups of 6 patients each selected at random. The patients were selected in such a way as to reduce as far as possible the parameters that would make it difficult to interpret the results. Both from the point of view of the numbers of patients who responded to stimulation of ovulation as well as the numbers of pregnancies that were obtained, the intramuscular route seems to be preferable.

Influence of the frequency of gonadotropin-releasing hormone (GnRH) administration on ovulatory responses in women with anovulation.

In attempt to optimize gonadotropin-releasing hormone (GnRH) treatment of anovulation, we compared the effect of intravenous GnRH administration at three pulse intervals (PI) during 63 cycles in 30 anovulatory patients who had: (1) amenorrhea secondary to anorexia nervosa (group I: 10 patients, 21 cycles); (2) unexplained anovulation with normal to high luteinizing hormone plasma levels (group II: 12 patients, 24 cycles); and (3) polycystic ovarian disease (PCOD) (group III: 8 patients, 18 cycles). Ovulation was achieved more frequently in group I (85%) than in group II (41%) or in group III (50%). In both groups I and II, the frequency of ovulatory responses was not different with the PI used, and 6 of the 17 women treated for infertility conceived; 3 with 90-minute PIs, 2 with 64-minute PIs, and 1 with 128-minute PIs. In women with PCOD, seven of the nine ovulatory responses and three pregnancies were obtained with 128-minute PIs. The overweight women with PCOD did not respond reliably to GnRH at the doses used, i.e., 4 to 15 micrograms per pulse. In all groups, the urinary estrone and estradiol preovulatory peak, duration of luteal phase, progesterone levels, and preovulatory follicle diameter were unrelated to the frequency of GnRH administration.

[Pregnancies by fertilization in vitro. Biochemistry of the follicular fluid]. / Grossesses par fécondation in vitro. Biochimie du liquide folliculaire.

Fifty four follicular fluids containing 41 oocytes were sampled from 6 patients in which at least one pregnancy was obtained after IVF. Their biochemical composition has been correlated with the follicle maturity and oocyte quality. Three components have been assayed: steroids, prostanoids, proteolytic enzymes. Determinations of estrogens and total aromatisable androgens were carried out by the enzymatic technic of Nicolas and al.; progesterone and 17 OH progesterone by RIA. Development of in vitro cultured and fertilized oocytes appears to be improved when progesterone and estrogens concentrations in the follicular fluid are above 2 000 and 600 ng/ml respectively, with an A/E ratio under 1. On the other hand, prostanoids (T X B2, PGE2, PGF2 alpha determined by RIA) and proteolytic enzymes : (collagenolytic and kallikrein type activities) seemed related to ovulatory activity rather than to oocyte quality.

[Enzymatic determination of urinary estrogens. A 5-year experience in a hospital milieu]. / Dosages enzymatiques des estrogènes urinaires. Une expèrience de cinq ans en milieu hospitalier.

The enzymatic method for urinary estrogens determination from Nicolas et al. has become a useful tool for the management of infertility problems. It can be used for: investigation of ovarian by establishing the urinary estrogens profile during menstrual cycle, useful to: understand anomalies of the spontaneous cycle, explain some therapeutic failures during IVF attempts or artificial inseminations (AID or AIC); prediction of failures during IVF attempts during spontaneous cycles, and monitoring ovarian response during stimulated cycles in order to determine the trigger with hCG; monitoring ovulation during induction of ovulation in anovulatory patients stimulated with various drugs (clomiphene citrate, pure FSH combination of FSH and LH, GnRH ou analogs...) under various conditions of prescription and administration (oral, IM, intermittent pulsatile administration with portable pump with or without hypophyseal down regulation). This technique allows also exploration of androgens after changing main androgens (delta 4 A, T, DHEA, DHEA S) into estrogens through the action of placental aromatase, as well as appreciation of aromatase activity of some tissues in the presence of androgenic substrates. This paper gives the conclusions after 5 years of practice with this method and summaries different works published by the biologists who developed the method and by the clinicians who used its results.

[Principle and practice of in vitro fertilization. Role in the treatment of female sterility]. / Principe et réalisation de la fécondation in vitro. Place dans le traitement de la stérilité féminine.

In vitro fertilization (IVF) and embryo transfer (ET) appear to constitute a revolution in the reproductive sciences rather than merely a new technique in the treatment of sterility. Principle of IVF: IVF accomplishes in vitro the process than normally occurs in the oviduct between the ovulation of oocyte II and embryo implantation in the endometrium. This 4 day period (under normal conditions in the woman) involves 4 steps: recovery, fertilization, segmentation and transport. Performance of IVF: Recovery of the oocytes: The oocytes are recovered under celioscopic or echographic observation when they have completed cytoplasmic maturation and their first meiosis. A precise monitoring of ovulation (spontaneous or induced) should be performed using estrogen and LH assays. IVF provides an opportunity for evaluating the methods of ovulation induction and monitoring, as a function of the maturation of the oocytes recovered. Fertilization: When the oocyte has achieved maturing after several hours of incubation, fertilization is obtained 15 h contact with washed and capacitated spermatozoa (100 000/ml). This step is highly dependent on gametocyte quality: oocyte maturity and fecundity of spermatozoa, which can be estimated from the percentage of survival in the insemination medium. Segmentation occurs in culture at pH 7.28 in the presence of 5 per cent CO2 at 37 degrees C (pronucleus 15th, 2 blastomeres 26 h, 4-8 blastomeres 52 h). Embryo transfer is carried out when an embryo is present at 52 h. Only 1/10 of the embryo transfers result in successful implantation, which depends on the quality of the embryo; the quality can only be indirect criteria.(ABSTRACT TRUNCATED AT 250 WORDS)

[Various protocols for determining estrogens by the enzymatic method using estradiol dehydrogenase. Respective procedures and advantages]. / Les divers protocoles de dosage des estrogènes par la méthode enzymatique à l'estradiol déshydrogénase. Mode opératoire et avantages réciproques.

Up to now, more than 40.000 determinations of urinary estrogens (E1 + E2) have been carried out in routine clinical analysis by the enzymatic method using estradiol dehydrogenase. This method makes use of the transhydrogenating activity of the placental enzyme: this enzyme transfers hydrogen from NADP to NAD with recycling of the specific substrate (E1 + E2). For several years the necessary reagents have been commercially available in the form of a kit. Nonetheless, various improvements have been made to the measurement of reduced NAD, which accumulates in the reaction medium and is directly proportional to the concentration of the two estrogens. Three protocols are available at present: Spectrophotometric measurement at 340 nm (initial technique); Colorimetric measurement at 492 nm. The pink colour measured arises from the reduction of a tetrazolium salt (INT) by reduced NAD in a coupled system using diaphorase; Measurement by bioluminescence of the light energy liberated on the reduction of flavin derivatives by NADH. The reaction is mediated by various enzymes isolated from marine bacteria (FMN oxidoreductase and luciferase) in the presence of an aliphatic aldehyde (decanal). The procedure for each of these protocols is described as well as the means for controlling the linearity of the reaction. The choice of protocol is determined by the biological fluid available, the speed of response desired and the cost of the analysis.