Studies of a magnetically focused electrostatic mirror. I. Experimental test of the first order properties

When a uniform magnetic field is superimposed on a uniform electrostatic field, the combination can act as a magnetically focused mirror. This mirror is predicted to have aberrations of opposite sign to those of a magnetic lens and may therefore be useful as a corrector. We have built an electron optical system to test these ideas. The results are presented in two papers. This first paper describes the general design and the results of the measurements of the first order properties. The second paper (Tsai, F., J. Microsc. 197 (2000) 118-135) will describe the measurements of the aberration properties.

[The effect of different anesthetic procedures on hormone levels in women. Studies during an in vitro fertilization-embryo transfer (IVF-ET) program]. / Der Einfluss unterschiedlicher Anästhesieverfahren auf den Hormonhaushalt der Frau. Untersuchungen im Rahmen eines in vitro-Fertilisations-Embryotransfer-(IVF-ET-)Programms.

Different anaesthetic procedures that were used during an in vitro fertilisation and embryo transfer (IVF-ET) program have been analysed in order to determine their influence on plasma levels of estradiol, progesterone, prolactin, and beta-endorphin and results of IVF-ET. METHODS. Fifty-four patients awaiting transvaginal oocyte aspiration were randomised into three groups: (1) anaesthesia with ketamine as an induction agent and analgesic (n = 20); (2) general intubation anaesthesia using thiopentone for induction and enflurane for maintenance (n = 18); and (3) no anaesthesia (n = 16). Estradiol, progesterone, prolactin, and beta-endorphin were measured from day 3 to 14 referring to follicle aspiration. Differences between preoperative hormone levels and their intra- and postoperative peaks were analysed using the Kruskal-Wallis test (P < 0.03). The results were corrected using the Holms method (alpha = 0.05). RESULTS. No differences were observed in estradiol and progesterone levels (Figs. 1, 2). Prolactin levels were 1.4 times higher (P < 0.001) when ketamine was used and 2.2 times higher (P < 0.001) after short general anaesthesia than in the control group (Fig.3). Similar results were observed with respect to beta-endorphin: in comparison with the control group we found significant elevation by a factor of 2.1 when ketamine was used (P < 0.001). The discrepancy became even more marked with general anaesthesia: beta-endorphin was 3.9 times higher compared to the controls (P < 0.001) (Fig.4). Comparing the two groups who were given anaesthetics, prolactin and beta-endorphin levels were also significantly different (P < 0.001). The IVF procedure itself did not appear to be affected by different anaesthetic procedures during oocyte aspiration (Table 2). CONCLUSIONS. The increased prolactin and beta-endorphin plasma levels associated with ketamine and general anaesthesia reflect a significant alteration of the observed hormone levels. When anaesthesia is indicated, we try to avoid general intubation anaesthesia in favor of ketamine.

[Effect of different follicle puncture methods on hormone homeostasis in the woman. Studies within the scope of an in vitro fertilization-embryo transfer program]. / Der Einfluss unterschiedlicher Follikelpunktionsmethoden auf den Hormonhaushalt der Frau. Untersuchungen im Rahmen eines In-vitro-Fertilisation-Embryotransfer-Programmes.

Different methods for follicular puncture which were used in an in vitro fertilization-embryo transfer program have been analyzed in order to determine their influence on plasma levels of estradiol, progesterone, prolactin and beta-endorphins. Thirty-eight patients awaiting oocyte aspiration were randomized into a laparoscopic (n = 20) and an ultrasound-guided oocyte aspiration group (n = 18). No differences were observed as far as estradiol and progesterone levels and embryo transfer rates were concerned. When using the laparoscopic technique, prolactin levels were found to be elevated 1.5 times in comparison with the ultrasound-guided aspiration procedure, which is highly significant (p < 0.001). Also, beta-endorphins peaked at a significantly higher level during laparoscopy (27.8 vs. 20.7 mol/l, p < 0.001). The enhanced prolactin and beta-endorphin levels reflect an increased stress response during laparoscopy. With respect to less trauma and shorter duration of the procedure, we now perform the sonographically guided transvaginal aspiration technique in our program almost exclusively.

Immobility reflex evoked by vertical lifting of the rat.

It is assumed that the immobility reflex (IR) evoked in adult rats by sensory stimulation does not exceed a few seconds. However, we easily achieved a longer lasting (up to 3 min or longer) immobility state in most of the tested rats when they were grasped by hand and lifted to a specific upright position. Twenty male rats originating from two different albino populations could remain immobilized continuously in such a position for average durations of 138 and 48 s respectively, while in 20 hooded male rats and 20 albino female rats the mean immobility durations were 138 s and 36 s, respectively. It is suggested that IR evoked in rats is homologous with similar reflexes in other species, the assumption that the rat is not useful for IR studies deserts reconsideration.

Environmental temperature and maternal behavior in Rattus norvegicus.

In 14 female rats the daily duration of selected patterns of maternal behavior was registered for 10 successive days (from the 4th till the 13th day postpartum) for 180 min each day. On certain days the home cages of 7 females (experimental group) were cooled for 8 h, while the remaining 7 females constituted a control group. During the days of cooling the experimental females devoted to the care- giving behavior much more time than during the days without cooling. The drop in temperature influenced the intensity of maternal behavior not only in the early postpartum days, but also on the following days, and that behavior altered repeatedly according to temperature changes. The behavioral responses of females to the actual temperature changes emerge during the first 90 min of cooling. The results indicate that in the course of one maternal cycle the intensity of care-giving activities can be modified many times and relatively quickly, according to temperature changes.

The stability of motor activity in rats.

Individual differences in motor activity were investigated in two groups of male rats. One group contained non-homozygotic and the second homozygotic rats. In both groups the individual differences were similar and very pronounced. Starting from the age of about 3 months the level of motor activity in individual animals remained relatively stable until the age of at least 6 1/2 months. The results may be useful for certain behavioural investigations and for long-term pharmacological studies and bioassays.

Locomotor stereotypy in visually deprived kittens.

Thirty-two kittens from nine litters were observed in home-cages during the first 8 months of life. Eighteen kittens were visually deprived from birth by means of double linen hoods, while 14 served as controls. In 6 of the deprived kittens locomotor stereotypy was observed. The kittens usually shuttled along the front of the cage. The episodes of stereotypy developed fully in the fourth month of life and occupied on the average from 19 to 40 percent of observation time in different kittens. The stereotypy was not observed in any of the control kittens. It is proposed that reduction of sensory stimulation by visual deprivation evokes in some kittens a compensatory mechanism of stereotyped walking which supplies some kinesthetic and tactile stimulation.

The effect of stimuli emitted by sucklings on the course of their feeding by bitches.

A change in feeding behavior on the 15th and 16th day of the maternal cycle was observed in experimental bitches whose own litter was partly replaced, on the onset of the 15th day, by foster puppies 12-13 days younger. The number of feeding acts and the overall feeding time increased, as compared with the indices for 2 days preceding the exchange of puppies (the 13th and 14th day of the maternal cycle). In the control group, where puppies were not exchanged, no increase in the above behavioral indices was observed on the 15th and 16th day, and they remained at the level recorded on the 13th and 14th day of the cycle.

The effect of stimuli emitted by sucklings on tactile contact of the bitches with sucklings and on number of licking acts.

Bitches changed abruptly their maternal behavior on 15th and 16th day of the maternal cycle, following an exchange - on the beginning of 15th day - of some puppies from their own litter for other 2-3 days old puppies. The total time of tactile contact with puppies on days 15 and 16 greatly increased as compared with the 13th and 14th day, i.e., the days immediately preceding the exchange of puppies. The number of licking acts also increased. In control bitches, whose puppies were not exchanged, the indices of maternal behavior showed no increase on days 15 and 16, compared with days 13 and 14 of the maternal cycle. The foster 2-3 days old puppies were also a source of much stronger stimuli releasing care-giving reactions than the own, correspondingly older puppies.

Epimeletic (care-giving) vomiting in dogs: a study of the determinating factors.

Epimeletic vomiting fails to occur in a bitch when she is kept in en isolated box apart from her puppies and their nest-pen. However, vomiting is elicited immediately after the bitch is allowed to contact her puppies in the nest-pen. If the contact occurs in a new, unfamiliar place, vomiting is disrupted but reappears again after several contacts in the same place. When after feeding, a bitch is put into her own nest-pen where alien puppies are substituted for her own, their care-soliciting (et-epimeletic) behavior induces in her aggression or avoidance rather than vomiting. Vomiting is not disrupted when some of the exterior features of puppies have been changed. Epimeletic vomiting may occur some days prior to the proestrus of the bitch and, sometimes, even during proestrus and estrus periods. Under special environmental conditions epimeletic vomiting may occur even in male dogs. The appropriate care-soliciting behavior of properly reared, not satiated puppies, and their own nest-pen are the main factors which elicit epimeletic vomiting in dogs.

Use of non-selective reagents in direct thermometry.

A method has been developed for the simultaneous determination of sulphide and thiosulphate with non-selective reagents on the basis of the difference in their heats of reaction. Iodine solution was used as one reagent and bromine water as the other. An error diagram has been calculated and the theoretical errors compared with those obtained in practice.

Epimeletic vomiting in female dogs during the rearing process of their puppies.

The epimeletic behavior consisting in vomiting the digested food in the presence of puppies was described in postpartum bitches. It begins at first month after the birth of puppies and may last up to five months. The main stimuli eliciting vomiting is the presence of the puppies close to the mother in the nest-pen, and their et-epimeletic behavior consisting of following the bitch, jumping upon her, and licking her mouth. When the puppies are removed from the nest-pen, the epimeletic vomiting of ingested food is stopped either immediately or after a few days. It is suggested that there exists a specific epimeletic drive whose consummatory response is vomiting. The biological role of this drive is to secure food to puppies before they are able to secure it by themselves.

Application of direct thermometric analysis in iodometry.

Elementary chlorine was determined by a thermometric method using potassium iodide as reagent. The temperature rise corresponding to the heat of reaction was proportional to the chlorine content. Iodine formed in the reaction was also determined with sodium thiosulphate. The heat of the chlorine-iodide reaction is about five times that of the iodine-thiosulphate reaction. Direct determination with potassium iodide is simpler and more rapid than the indirect one.

Gravimetric determination of copper(II) with p-aminobenzoic acid.

A method has been developed for the gravimetric determination of 20-100 mg of copper(II) with p-aminobenzoic acid. Ag, Hg(II), Pb, Al, Fe(II), Bi, Sb(III) and Sn(II) interfere, but Zn, Co(II), Ni and Cd do not. The precipitate can be weighed after drying at 80-100 degrees , or can be ignited to copper(II) oxide at temperatures above 400 degrees , and weighed in this form.