Decoherence-assisted spectroscopy of a single Mg+ ion.

We describe a high-resolution spectroscopy method in which the detection of single excitation events is enhanced by a complete loss of coherence of a superposition of two ground states. Thereby, transitions of a single isolated atom nearly at rest are recorded efficiently with high signal-to-noise ratios. Spectra display symmetric line shapes without stray-light background from spectroscopy probes. We employ this method on a (25)Mg+ ion to measure one-, two-, and three-photon transition frequencies from the 3S ground state to the 3P, 3D, and 4P excited states, respectively. Our results are relevant for astrophysics and searches for drifts of fundamental constants. Furthermore, the method can be extended to other transitions, isotopes, and species. The currently achieved fractional frequency uncertainty of 5 × 10(-9) is not limited by the method.

Quantum walks with nonorthogonal position states.

Quantum walks have by now been realized in a large variety of different physical settings. In some of these, particularly with trapped ions, the walk is implemented in phase space, where the corresponding position states are not orthogonal. We develop a general description of such a quantum walk and show how to map it into a standard one with orthogonal states, thereby making available all the tools developed for the latter. This enables a variety of experiments, which can be implemented with smaller step sizes and more steps. Tuning the nonorthogonality allows for an easy preparation of extended states such as momentum eigenstates, which travel at a well-defined speed with low dispersion. We introduce a method to adjust their velocity by momentum shifts, which allows us to experimentally probe the dispersion relation, providing a benchmarking tool for the quantum walk, and to investigate intriguing effects such as the analog of Bloch oscillations.

Quantum walk of a trapped ion in phase space.

We implement the proof of principle for the quantum walk of one ion in a linear ion trap. With a single-step fidelity exceeding 0.99, we perform three steps of an asymmetric walk on the line. We clearly reveal the differences to its classical counterpart if we allow the walker or ion to take all classical paths simultaneously. Quantum interferences enforce asymmetric, nonclassical distributions in the highly entangled degrees of freedom (of coin and position states). We theoretically study and experimentally observe the limitation in the number of steps of our approach that is imposed by motional squeezing. We propose an altered protocol based on methods of impulsive steps to overcome these restrictions, allowing to scale the quantum walk to many, in principal to several hundreds of steps.

[Glucocorticoid therapy in collagen diseases diseases]. / Glucocorticoidtherapie bei Kollagenosen.

Glucocorticoids are irreplaceable for the treatment of connective tissue diseases due to their strong and rapid anti-inflammatory and immuno-modulatory effects. Its use and their dosage depend on the activity of the disease and organ manifestations. There is no alternative to high doses, often even as intravenous pulse therapy, in life-threatening situations with imminent organ failure. Despite an additional immuno- suppressive medication, glucocorticosteroids are mandatory for long-term treatment in most cases. In special situations like high age, gravity or comorbidities like renal failure or hepatosis, glucocorticosteroids are the option with the least possible potential for complications. In the future, new corticosteroids and steroid sparing immuno-suppressants like biologics will be able to reduce the spectrum and the severity of corticoid-induced side effects. Modern state-of-the-art therapeutic regimens for patients with connective tissue diseases should not only be able to sufficiently control the disease activity but also include the prophylaxis of associated comorbidities like arteriosclerosis, osteoporosis or infections.

Fetal echocardiography: retrospective review of clinical experience and an evaluation of indications.

OBJECTIVE: To assess the indications, use, and yield of fetal echocardiography. METHODS: We reviewed our 8-year experience with fetal echocardiography at a large health maintenance organization in northern California to assess the yield of abnormal findings for each indication and the accuracy of prenatal cardiac diagnosis. The study included 915 fetuses undergoing fetal echocardiography between 18-38 weeks' gestation because of accepted indications. All live-born infants had the presence or absence of congenital heart disease (CHD) confirmed postnatally. RESULTS: Family history of CHD led to 34% of all fetal echocardiography studies, with a detection rate of 0.7%. Maternal diabetes mellitus accounted for 28% of all studies, with a detection rate of 1.2%. Exposure of mothers to a potential teratogen led to 48 studies, but no abnormalities were detected. Only 4% of fetal echocardiograms were obtained because of a suspected heart defect noted on a screening obstetric sonogram; this indication had a detection rate of 68% and yielded by far the most cases of severe CHD. Based on the expected occurrence rate of severe CHD in our closed referral system, only about 15% were referred for fetal echocardiography and detected prenatally. CONCLUSION: Basing fetal echocardiography referral on risk factors misses most clinically significant detectable CHD.

Health status and timing of onset of prenatal care: is there an association among low-income women?

We examined medical obstetric conditions predating pregnancy and current symptoms as predictors of the timing of the start of prenatal care among low-income women in Snohomish County, Washington. The investigation was a cross-sectional survey with retrospective record review. Subjects were 473 women who sought care through the community health center network, which was the only provider of prenatal care for low-income women in the county at the time of the study. Women with a history of two or more medical or obstetric conditions were more likely than those without such histories to seek prenatal care early in pregnancy. Women who, in the current pregnancy, had few physical symptoms were more likely to delay seeking prenatal care than symptomatic women. Among this relatively homogeneous group, sociodemographic characteristics were not associated with the timing of entry into prenatal care. The findings help to explain the patterns of prenatal care use of certain groups, and suggest avenues for intervention to improve use among low-income women.

Asymmetric septal hypertrophy in infants of diabetic mothers. Fetal echocardiography and the impact of maternal diabetic control.

Maternal hyperglycemia may result in fetal hyperinsulinemia and asymmetric septal hypertrophy, macrosomia, and hypoglycemia in infants of diabetic mothers. We monitored glycosylated hemoglobin levels in 61 pregnant diabetic women each trimester as an index of maternal glycemic control and did serial fetal echocardiograms starting at 18 weeks of gestation. At delivery, cord blood C-peptide levels were obtained as an index of fetal hyperinsulinemia. Infants were assessed for hypoglycemia, macrosomia and septal thickening by echocardiography. Nineteen of the 61 infants (31%) had septal hypertrophy, were heavier, and had higher cord blood C-peptide levels and lower serum glucose levels than unaffected infants. Maternal glycosylated hemoglobin levels were higher during the third trimester in mothers of affected infants. Our data support a possible relationship between third-trimester maternal hyperglycemia and neonatal asymmetric septal hypertrophy, macrosomia, and hypoglycemia.

Fetal atrioventricular valve insufficiency associated with nonimmune hydrops: a two-dimensional echocardiographic and pulsed Doppler ultrasound study.

Of 466 fetuses who underwent cardiac ultrasound examination with cross-sectional and M mode echocardiography and pulsed Doppler ultrasound and in whom we were able to follow the natural history, 12 were found to have atrioventricular valve insufficiency and nonimmune hydrops. Eleven fetuses (all of whom had structural heart disease) died either in utero or during the early postnatal period. In the one surviving hydropic fetus with supraventricular tachyarrhythmia and atrioventricular valve regurgitation but without structural heart disease, all the abnormalities disappeared on treatment with digoxin and verapamil. Seven fetuses who had atrioventricular valve insufficiency but did not develop nonimmune hydrops all survived pregnancy and the early neonatal period. The syndrome of atrioventricular valve insufficiency, nonimmune hydrops, and structural heart disease has a poor prognosis. The hydrops in this instance reflects fetal cardiac failure related to venous hypertension and low colloid oncotic pressure.

Recognition of fetal arrhythmias by echocardiography.

Fetal arrhythmias were detected in 33/198 high risk pregnancies from 21 weeks to term. Using the two-dimensional echocardiographic image of the fetal heart as a guide, the M-mode beam was directed to define the motion of the ventricular and atrial walls and atrioventricular valve or semilunar valves. Atrial contraction was defined either by the atrial wall motion or from the A-point of the atrioventricular valve. Ventricular contraction was defined by closure of the atrioventricular valve (C-point), the onset of ventricular wall contraction, or from the semilunar valve opening. Ladder diagrams of the sequence of atrial and ventricular activation were constructed to define the temporal sequence of these events. Premature atrial contractions were present in 12. In one fetus this arrhythmia converted into supraventricular tachycardia while in the other 11 fetuses the course was benign. Two fetuses had premature ventricular contractions. Supraventricular tachycardia was noted in five fetuses. One with hydrops at 29 weeks returned to sinus rhythm following maternal administration of procainamide. A second hydropic fetus with paroxysmal atrial tachycardia and hydrops failed to respond to digitalis, propranolol, procainamide, verapamil, or amiodarone, and died shortly after cesarean section. Two mature fetuses had tachycardia close to term and were treated after cesarean section. One fetus with runs of atrial tachycardia died in utero. Three fetuses had complete heart block, two of whom were from mothers with connective tissue diseases. In four fetuses, there was bradycardia of less than 100/minute lasting more than 30 seconds, but these episodes disappeared in 2 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of M-mode echocardiographic measurement of right ventricular wall thickness obtained by the subcostal and parasternal approach in children.

Right ventricular (RV) wall thickness was measured from M-mode echocardiograms at end-diastole from both the parasternal and subcostal approaches in 50 children of various body surface areas (0.24 to 1.68 m2). The measurements were obtained from M-mode recordings generated from sector scans to ensure precise location and position. Twenty-three children had normal hearts, and 27 had various congenital heart defects that may be associated with RV hypertrophy. Corresponding measurements of the RV wall thickness at end-diastole from the 2 approaches were similar. Subcostal echocardiographic measurement of RV wall thickness was found to be a reliable alternative to parasternal measurement in children with normal hearts and in those with congenital heart disease and RV hypertrophy.

Study of the infradiaphragmatic total anomalous pulmonary venous connection with cross-sectional and pulsed Doppler echocardiography.

We studied neonates with the infradiaphragmatic form of total anomalous pulmonary venous drainage by a combination of cross-sectional echocardiography and pulsed Doppler ultrasound. The diagnosis by ultrasound was made prospectively in all six patients. Three large vascular channels could be observed passing through the diaphragm from the subcostal parasagittal plane. The vessels were identified as the descending aorta (to the left), the inferior vena cava (to the right), and the anomalous pulmonary venous channel (in the center). The vessels were insonated in turn, with pulsed Doppler ultrasound, and the characteristic normal flow signals in the aorta and inferior vena cava were obtained. The signal from the anomalous pulmonary vein was a continuous venous signal, the direction of flow being away from the heart. Pulsed Doppler ultrasound allows accurate recognition of the anomalous pulmonary venous channel without the use of contrast echocardiography.

Two-dimensional echocardiographic determination of aortic and pulmonary artery sizes from infancy to adulthood in normal subjects.

The aorta, right pulmonary artery and pulmonary trunk were measured from the 2-dimensional echocardiogram (2-D echo) of 110 normal subjects aged 1 day to 18 years. The vessel diameters were measured from the parasternal short-axis view, the suprasternal long-axis view and the suprasternal short-axis view. Measurements were made at end-systole and at end-diastole and in both an axial and lateral direction where possible. When analyzed with respect to body surface area (BSA), the echocardiographic measurements were linearly related to the square root of the BSA, and there was inequality of variance around the relation. To establish a range of normal values for each vessel dimension, a weighted regression analysis was used to produce estimates of the regression line and a set of tolerance intervals. The systolic vessel dimension was larger than the diastolic vessel dimension and the measurement of a vessel in an axial direction was larger than the measurement of the same vessel in a lateral direction. In general, when a vessel was measured in several views, the largest diameter was obtained using the view that imaged the vessel in cross section. These data on normal values for the echocardiographic measurement of the aorta and pulmonary arteries at different BSAs should be useful for identifying patients with abnormalities in arterial size and for the serial assessment of arterial size in children who have undergone surgical or medical therapy.

Isolated ventricular inversion: two-dimensional echocardiographic findings and a review of the literature.

In a cyanotic newborn infant, the diagnosis of isolated ventricular inversion in situs solitus was made from the two-dimensional echocardiographic examination and later confirmed at cardiac catheterization and surgery. The four-chamber views were especially useful for identifying the normal atrial situs and discordant atrioventricular connections in this infant. The normal relationships of the great arteries to each other (aortic valve rightward, posterior, and inferior to the pulmonary valve; great arteries coiled around each other) and to the ventricles (mitral-aortic fibrous continuity, well-developed subpulmonic conus) were well defined in the subcostal views. A review of the medical literature revealed a total of 12 cases of isolated ventricular inversion, most of which were diagnosed only at postmortem examination. The two-dimensional echocardiogram provides a rapid, safe technique for prompt diagnosis in these very sick cyanotic infants.