A digital feedback controller for stabilizing large electric currents to the ppm level for Feshbach resonance studies.

Magnetic Feshbach resonances are a key tool in the field of ultracold quantum gases, but their full exploitation requires the generation of large, stable magnetic fields up to 1000 G with fractional stabilities of better than 10-4. Design considerations for electromagnets producing these fields, such as optical access and fast dynamical response, mean that electric currents in excess of 100 A are often needed to obtain the requisite field strengths. We describe a simple digital proportional-integral-derivative current controller constructed using a field-programmable gate array and off-the-shelf evaluation boards that allows for gain scheduling, enabling optimal control of current sources with non-linear actuators. Our controller can stabilize an electric current of 337.5 A to the level of 7.5 × 10-7 in an averaging time of 10 min and with a control bandwidth of 2 kHz.

A three-dimensional steerable optical tweezer system for ultracold atoms.

We present a three-dimensional steerable optical tweezer system based on two pairs of acousto-optic deflectors. Radio frequency signals used to steer the optical tweezers are generated by direct digital synthesis, and multiple time averaged cross beam dipole traps can be produced through rapid frequency toggling. We produce arrays of ultracold atomic clouds in both horizontal and vertical planes and use this to demonstrate the three-dimensional nature of this optical tweezer system.

Multiple scattering dynamics of fermions at an isolated p-wave resonance.

The wavefunction for indistinguishable fermions is anti-symmetric under particle exchange, which directly leads to the Pauli exclusion principle, and hence underlies the structure of atoms and the properties of almost all materials. In the dynamics of collisions between two indistinguishable fermions, this requirement strictly prohibits scattering into 90° angles. Here we experimentally investigate the collisions of ultracold clouds fermionic (40)K atoms by directly measuring scattering distributions. With increasing collision energy we identify the Wigner threshold for p-wave scattering with its tell-tale dumb-bell shape and no 90° yield. Above this threshold, effects of multiple scattering become manifest as deviations from the underlying binary p-wave shape, adding particles either isotropically or axially. A shape resonance for (40)K facilitates the separate observation of these two processes. The isotropically enhanced multiple scattering mode is a generic p-wave threshold phenomenon, whereas the axially enhanced mode should occur in any colliding particle system with an elastic scattering resonance.

Steerable optical tweezers for ultracold atom studies.

We report on the implementation of an optical tweezer system for controlled transport of ultracold atoms along a narrow, static confinement channel. The tweezer system is based on high-efficiency acousto-optic deflectors and offers two-dimensional control over beam position. This opens up the possibility for tracking the transport channel when shuttling atomic clouds along it, forestalling atom spilling. Multiple clouds can be tracked independently by time-shared tweezer beams addressing individual sites in the channel. The deflectors are controlled using a multichannel direct digital synthesizer, which receives instructions on a submicrosecond time scale from a field-programmable gate array. Using the tweezer system, we demonstrate sequential binary splitting of an ultracold 87Rb cloud into 2(5) clouds.

Laser based accelerator for ultracold atoms.

We present our first results on our implementation of a laser based accelerator for ultracold atoms. Atoms cooled to a temperature of 420 nK are confined and accelerated by means of laser tweezer beams, and the atomic scattering is directly observed in laser absorption imaging. The optical collider has been characterized using 87Rb atoms in the |F=2, m(F)=2] state, but the scheme is not restricted to atoms in any particular magnetic substates and can readily be extended to other atomic species as well.

Mesoscopic atomic entanglement for precision measurements beyond the standard quantum limit.

Squeezing of quantum fluctuations by means of entanglement is a well-recognized goal in the field of quantum information science and precision measurements. In particular, squeezing the fluctuations via entanglement between 2-level atoms can improve the precision of sensing, clocks, metrology, and spectroscopy. Here, we demonstrate 3.4 dB of metrologically relevant squeezing and entanglement for greater, similar 10(5) cold caesium atoms via a quantum nondemolition (QND) measurement on the atom clock levels. We show that there is an optimal degree of decoherence induced by the quantum measurement which maximizes the generated entanglement. A 2-color QND scheme used in this paper is shown to have a number of advantages for entanglement generation as compared with a single-color QND measurement.

Nondestructive probing of Rabi oscillations on the cesium clock transition near the standard quantum limit.

We report on the nondestructive observation of Rabi oscillations on the Cs clock transition. The internal atomic state evolution of a dipole-trapped ensemble of cold atoms is inferred from the phase shift of a probe laser beam as measured using a Mach-Zehnder interferometer. We describe a single color as well as a two-color probing scheme. Using the latter, measurements of the collective pseudospin projection of atoms in a superposition of the clock states are performed and the observed spin fluctuations are shown to be close to the standard quantum limit.

[Vaginal hysterectomy in non-prolapsed uterus]. / Vaginal hysterektomi ved non-prolaberet uterus.

INTRODUCTION: There is an increasing number of methods available for removing the uterus, but no multicentre, randomised, clinical trials are available to show which type of operation ensures the best outcome for the patient. The charts of 207 vaginal hysterectomies were reviewed in this descriptive study. The aim was to examine whether vaginal hysterectomy might be an alternative for a group of patients. MATERIAL AND METHODS: Only patients with a previous, vaginal birth were entered in the study (four patients had not given birth). A uterus weight of 500-600 g was the upper limit set by our group for the use of the vaginal route. Patient characteristics, data from the operations, complications, and histological examinations of the uterus were analysed. RESULTS: The mean operation time was 61 min (95% CI 58-64 min), range 25-115 min. The difference between preoperative and postoperative haemoglobin was 1.1 mmol/l (95% CI 1.0-1.2 mmol/l). The mean length of hospital stay was 2.9 days (95% CI 2.7-3.1 days). The complications were 1) febrile morbidity; 17 (8%) (95% CI 4-12%); 2) urinary tract injury, 3 (2%) (95% CI 0-3%); 3) unforeseen need for major surgery (including conversion to abdominal hysterectomy), 3 (2%) (95% CI 0-3%). DISCUSSION: In some patients, vaginal hysterectomy is a good alternative.

Structural properties of two-component coulomb crystals in linear paul traps.

We report on structural properties of two-component Coulomb crystals in a linear Paul trap. The crystals consist of two laser cooled ion species, 24Mg+ and 40Ca+. The lighter 24Mg+ ions form an inner cylindrical crystal structure surprisingly similar to that of an infinitely long single component crystal, while the outermost shell of the surrounding 40Ca+ ions have a spheroidal shape, which is highly insensitive to the presence of the 24Mg+ ions. Observed changes in the radial separation of the two ion species with the radius of the inner cylindrical crystal is explained by a simple model.

Antibacterial properties of human amnion and chorion in vitro.

OBJECTIVE: The purpose of the present study was to explore the direct effects of amnion and chorion on bacterial growth in vitro including the antibacterial spectrum. Chorioamniotic membranes were obtained under sterile conditions from 13 healthy women undergoing elective cesarean section at term. Likewise, chorioamniotic membranes were obtained from 10 healthy women with spontaneous vaginal delivery at term. Five strains of Hemolytic streptococci group B (GBS) were tested and one clinical isolate of the following species or bacterial groups: Hemolytic streptococcus group A, Staphylococcus aureus, Staphylococcus saprophyticus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter calcoaceticus and Lactobacillus species. Bacteriological media included (1) blood-agar medium; (2) a transparent agar medium for submerged cultures; and (3) a nutrient broth medium. RESULTS: An inhibitory effect of fetal membranes against a range of bacteria was found. Consistent results were obtained in experiments with cultures on agar and cultures suspended in agar (membranes from eight women in both studies). In experiments with liquid cultures (seven women) only chorion showed a marginal inhibitory effect. All strains were inhibited, but the most pronounced inhibition was obtained for streptococcus group A, S. aureus and S. saprophyticus by both chorion and amnion. CONCLUSION: This study demonstrated an inhibitory effect of the fetal membranes on a diverse panel of bacteria

Chorioamniotic membranes constitute a competent barrier to group b streptococcus in vitro.

OBJECTIVE: To study the penetration of group B streptococcus (GBS) through human chorioamniotic membranes in vitro. STUDY DESIGN: Chorioamniotic membranes from seventeen healthy women were mounted onto glass cylinders and placed in tissue culture trays constituting a two-compartment system with a maternal compartment internally and a fetal compartment externally. GBS from healthy pregnant women and from newborn babies with sepsis were added to the maternal compartment at densities from 10(7) to 10(9) colony forming units (cfu) per ml. RESULTS: Irrespective of inoculum density, GBS was not recovered from the fetal compartment within a 20 h incubation period. By histology, micro-colonies of GBS were found on the maternal surface after 8 h, but invasion of the morphologically intact membranes was not observed. A five log reduction in cfu occurred in the maternal compartment with amnion when GBS were suspended in saline. CONCLUSION: In this in vitro model the membranes appear to constitute an effective barrier against ascending infection.

Microbiology of semen specimens from males attending a fertility clinic.

The relationship between semen quality, pyospermia and bacteriology was studied in 201 semen specimens from male patients attending a fertility clinic. Semen quality parameters were within normal limits in 115 (57%) patients, slightly reduced in 60 (30%), and 26 (13%) had findings indicating reduced fertility. Twelve patients (6%) had pyospermia. In 182 patients, 552 microorganisms were detected, including Enterobacteriaceae (2.8%), Gardnerella vaginalis (9.6%), Chlamydia trachomatis (1.6%), Mycoplasma genitalium (0.9%), and Ureaplasma urealyticum (11.8%). Semen quality was neither related to occurrence of microorganisms nor pyospermia. However, pyospermia was associated with simultaneous growth of Gardnerella vaginalis and Ureaplasma urealyticum. The exact nature of this association could not be ascertained, in as far as the males were not questioned about urethritis symptoms.

Pyospermia and preterm, prelabor, rupture of membranes.

OBJECTIVES: To investigate the possible association between presence of clinically unrecognized, specific genito-urinary tract microorganisms in men and preterm, prelabor rupture of membranes (PPROM) in their spouses. STUDY DESIGN: Case control study. Eleven couples with PPROM were enrolled in the case group and 18 couples with normal pregnancies in the control group. For each man, samples of urine and semen were collected and a urethra swab was obtained. Microbiological assessment included, for each woman, cultures from vagina/cervix, urine and placenta. A smear from the vagina was obtained. RESULTS: In the case group, pyospermia was found in three men. Two of these men, as well as their spouses, were Chlamydia trachomatis positive, and in the third man no microorganisms could be detected. None of the controls had pyospermia (p = 0.045). Among the eight cases without pyospermia one man and one women with Chlamydia trachomatis was found, but their spouses were negative. In the control group, no Chlamydia trachomatis was detected (p = 0.014). Among the women two cases and one control had positive culture of Group B streptococci (NS). CONCLUSION: We suggest that the genital microflora of the man is associated with PPROM.

[Measurement of luteinizing hormone in urine and donor insemination]. / Urin-luteiniserende hormon måling og insemination ved donor.

The pregnancy rates after artificial insemination with donor sperm (AID) were investigated in 15 patients using the Ovu-Quck urinary LH-test to determine the time of ovulation. In 15 patients the time of ovulation and AID were determined by basal body temperature charts and served for comparison. Five patients in the Ovu-Quick group and 2 patients in the control group were excluded. The pregnancy rates in the Ovu-Quick group, four (40%) of 10 patients, were not statistically different from the pregnancy rates in the control group, 4 (31%) of 13 patients. It is concluded that a simple and rapid urinary LH-test might be an important parameter for predicting the time of ovulation.

Xanthine and hypoxanthine in amniotic fluid during pregnancy.

Xanthine and hypoxanthine are indicators of cellular hypoxia. The purpose of our study was to establish a reference range for the concentrations of xanthine and hypoxanthine in amniotic fluid. Of a total of 38 included in the investigation, 27 pregnant women were found to have low values for xanthine (less than 1.2 mumol/l) and hypoxanthine (less than 0.4 mumol/l). To our knowledge, this is the first attempt to define a reference range for xanthine and hypoxanthine concentration in amniotic fluid during pregnancy.

Prognostic value of semen analyses in infertility evaluation (male fertility/life-table analysis).

The aim of the present study was to evaluate which of the various parameters of semen analysis that are most significantly related to the obtainment of pregnancy. A follow up questionnaire was sent to 1953 couples, who had been examined for infertility, and 1,480 (76%) replied. We focused on 713 of these couples, in whom the female partner had a normal fertility set-up (potentially fertile). This study suggests that sperm vitality and sperm concentration bear the most significant relation to pregnancy. Evaluation of a couple's fertility potential by means of the life-table method shows a gradual increase in the pregnancy rate of all couples, irrespective of semen quality, during a observation period of 10 years. The pregnancy rate after 5 years was 14% in a group with reduced semen quality and 44% in a group with normal semen quality.

Effects of mesalazine substitution on salicylazosulfapyridine-induced seminal abnormalities in men with ulcerative colitis.

Some semen characteristics of eight male patients with clinically inactive ulcerative colitis were investigated. Semen analysis was carried out twice during salicylazosulfapyridine (SASP) treatment and repeated twice after at least 3 months' treatment with mesalazine. The motility variables all showed significant improvement during mesalazine treatment: the graded motility (p less than 0.05), motility in percentage (p less than 0.01), and the penetration in egg white (p less than 0.05). The semen plasma was analyzed for mesalazine and the metabolite Ac-mesalazine during both regimens. There was no difference in the semen plasma concentration of mesalazine during the two regimens, whereas Ac-mesalazine was significantly higher during mesalazine treatment than during SASP treatment, indicating that other SASP metabolites, most likely sulfapyridine, are the agent causing the abnormal sperm characteristics. We suggest that pure mesalazine preparations are a safer alternative in young men with chronic inflammatory bowel disease.

Prazosin, an adrenergic blocking agent inadequate as male contraceptive pill.

The purpose of this study was to investigate the efficacy and the acceptability of Prazosin as a male contraceptive pill. Acceptable antifertility drugs for men are proving difficult to produce, and the possibility of using pharmacological agents to block selectively or to inhibit normal sperm transport through the male genital tract is an interesting approach. Prazosin administered in doses up to 10 mg/day did not cause azoospermia following ejaculation. In conclusion, we have not been able to confirm either the efficacy or the acceptability of the alpha 1-adrenoceptor antagonist Prazosin as a male contraceptive drug. Homonnai et al. confirmed the fact that phenoxybenzamine blocks ejaculation, but it should be noted that although both drugs are alpha 1-adrenoceptor blocking agents, they are not chemically identical.

PIP: The efficacy and acceptability of the adrenoceptive-blocking agent, Prazosin, as a male contraceptive pill were investigated in 10 healthy men who had been referred for sexual sterilization. Prazosin was administered by mouth twice a day at a dosage that was increased from 0.5 mg to a maximum of 5.0 mg for an average of 40 days (range 5-110 days). No significant differences were recorded in pretreatment and post-treatment values for semen volume or sperm concentration. Nor were there any significant changes in sperm penetration or motility as a result of treatment with Prazosin. No changes were noted in either blood chemistry or blood pressure. Postejaculation urine collected to detect possible signs of retrograde ejaculation contained no spermatozoa. 5 (50%) of volunteers complained of side effects, including minor vertigo, palpitation, and generalized discomfort. Overall these findings failed to confirm either the efficacy or the acceptability of Prazosin as a male contraceptive drug. Another adrenoceptive antagonist, phenoxybenzamine, has been shown to be an effective antifertility agent without significant side effects at doses as high as 30 mg/day. However, it should be noted that this agent is not chemically identical to Prazosin.

[Male contraception]. / Mandlig kontraception.

PIP: Male contraceptive drugs meeting the criteria of efficacy, easy applicability and reversibility -- and also having limited side effects -- are discussed. These drugs affect the hypothalamus, the hypophysis, the ductus deferens, and the testes. Gestagens inhibit the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Gonadotropic hormones inhibit spermatogenesis by producing intratesticular concentration of testosterone. Recently, a combination of gestagen and androgen has been used to avoid decreased libido. Oral medroxyprogesterone acetate and percutaneous testosterone produce azoospermia, but with serious side effects, i.e., hirsutism and acne; however, they can be reduced by iv administration. Cyproterone acetate inhibits androgen secretion, and a daily dosage of 5-10 mg slightly reduces the sperm count; however, higher doses can lead to thromboembolitic effects. Combining cyproterone with an androgen prevents negative effects on the libido. Buserelin administered iv or as a nasal spray stimulates the secretion of LH and FSH from the hypophysis 20-40 times more effectively than does natural LH release of the hormone (LH-RH). Gossypol exerts its inhibitory effect on the epithelium of testes, but can cause hypokalemia. It has been used successfully in a Chinese experiment involving 9000 men who received daily oral doses of 20 mg for 60-70 days. Cytostatic agents also produce azoospermia, but are not recommended. Implantation of a copper wire into the ductus deferens has been tried in animal experiments with mixed results. Vasectomy has been performed on 50 million men since the 1960's (48,000 in 1981 in Denmark). It has to be regarded as a partially irreversible operation. The oral administration of the adrenergic blocking agent, phenoxybenzamine, at the rate of 20 mg per day has produced azoospermia; however, more research is needed to understand its side effects. Finally, chlorohydrin is not usable because of its neurotoxic and nephrotoxic effects.^ieng