Control of Spatial Correlations between Rydberg Excitations using Rotary Echo.

We manipulate correlations between Rydberg excitations in cold atom samples using a rotary-echo technique in which the phase of the excitation pulse is flipped at a selected time during the pulse. The correlations are due to interactions between the Rydberg atoms. We measure the resulting change in the spatial pair correlation function of the excitations via direct position-sensitive atom imaging. For zero detuning of the lasers from the interaction-free Rydberg-excitation resonance, the pair-correlation value at the most likely nearest-neighbor Rydberg-atom distance is substantially enhanced when the phase is flipped at the middle of the excitation pulse. In this case, the rotary echo eliminates most uncorrelated (unpaired) atoms, leaving an abundance of correlated atom pairs at the end of the sequence. In off-resonant cases, a complementary behavior is observed. We further characterize the effect of the rotary-echo excitation sequence on the excitation-number statistics.

Imaging spatial correlations of Rydberg excitations in cold atom clouds.

We use direct spatial imaging of cold 85Rb Rydberg atom clouds to measure the Rydberg-Rydberg correlation function. The results are in qualitative agreement with theoretical predictions [F. Robicheaux and J. V. Hernández, Phys. Rev. A 72, 063403 (2005)]. We determine the blockade radius for states 44D(5/2), 60D(5/2), and 70D(5/2) and investigate the dependence of the correlation behavior on excitation conditions and detection delay. Experimental data hint at the existence of long-range order.

High-brightness Cs focused ion beam from a cold-atomic-beam ion source.

We present measurements of focal spot size and brightness in a focused ion beam system utilizing a laser-cooled atomic beam source of Cs ions. Spot sizes as small as (2.1 ± 0.2) nm (one standard deviation) and reduced brightness values as high as (2.4 ± 0.1) × 107 A m-2 Sr-1 eV-1 are observed with a 10 keV beam. This measured brightness is over 24 times higher than the highest brightness observed in a Ga liquid metal ion source. The behavior of brightness as a function of beam current and the dependence of effective source temperature on ionization energy are examined. The performance is seen to be consistent with earlier predictions. Demonstration of this source with very high brightness, producing a heavy ionic species such as Cs+, promises to allow significant improvements in resolution and throughput for such applications as next-generation circuit edit and nanoscale secondary ion mass spectrometry.

Bright focused ion beam sources based on laser-cooled atoms.

Nanoscale focused ion beams (FIBs) represent one of the most useful tools in nanotechnology, enabling nanofabrication via milling and gas-assisted deposition, microscopy and microanalysis, and selective, spatially resolved doping of materials. Recently, a new type of FIB source has emerged, which uses ionization of laser cooled neutral atoms to produce the ion beam. The extremely cold temperatures attainable with laser cooling (in the range of 100 µK or below) result in a beam of ions with a very small transverse velocity distribution. This corresponds to a source with extremely high brightness that rivals or may even exceed the brightness of the industry standard Ga+ liquid metal ion source. In this review we discuss the context of ion beam technology in which these new ion sources can play a role, their principles of operation, and some examples of recent demonstrations. The field is relatively new, so only a few applications have been demonstrated, most notably low energy ion microscopy with Li ions. Nevertheless, a number of promising new approaches have been proposed and/or demonstrated, suggesting that a rapid evolution of this type of source is likely in the near future.

Determinants of coronary remodeling in transplant coronary disease: a simultaneous intravascular ultrasound and Doppler flow study.

BACKGROUND: Coronary remodeling plays a significant role in lumen loss in transplant allograft vasculopathy (TxCAD), but the determinants of remodeling are unknown. We assessed the relationship between remodeling and plaque topography, coronary compliance, and blood flow in TxCAD. METHODS AND RESULTS: One artery in each of 27 transplant patients was investigated with simultaneous intravascular ultrasound and coronary flow measurements (basal and hyperemic by Doppler flow wire). At 4 to 8 different cross sections (mean 5.1+/-1. 2), plaque topography (concentric or eccentric) was determined, and total vessel area, lumen area, and intimal/medial area (IMA) were measured. Mean remodeling ratio (vessel area/IMA) in eccentric lesions (E, n=28) was significantly larger than that in concentric lesions (C, n=70) (E 5.87+/-0.93 versus C 3.58+/-0.62; P<0.001), despite similar IMA (E 3.89+/-0.68 versus C 3.90+/-0.41; P=NS) and distribution of imaged segments. Remodeling ratio was consistently larger in eccentric lesions in all 3 vessel segments when analyzed separately, and mean remodeling ratio for each artery was larger in vessels with predominantly eccentric lesions. Coronary compliance ([Delta lumen area/diastolic lumen area]/Delta mean arterial pressure x 10(3)) was also significantly greater in eccentric lesions versus concentric lesions (proximal 1.00+/-0.39 versus 0.22+/-0.04; mid 0.71+/-0.17 versus 0.21+/-0.10; distal 0.43+/-0.13 versus 0. 01+/-0.08; all P<0.01). Coronary flow reserve was also significantly higher in coronary arteries with primarily eccentric lesions (E 2. 49+/-0.64 versus C 1.87+/-0.28; P<0.01). CONCLUSIONS: Vessel remodeling in transplant vasculopathy is significantly greater in eccentric lesions than in concentric lesions, possibly due to greater coronary compliance and resistive vessel function.

Role of vascular remodeling in the pathogenesis of early transplant coronary artery disease: a multicenter prospective intravascular ultrasound study.

BACKGROUND: Luminal narrowing in transplant coronary artery disease is thought to be primarily caused by intimal proliferation, and the role of vascular remodeling is less certain. METHODS AND RESULTS: We studied cardiac allografts from 83 prospectively recruited patients immediately and 1 year after transplant using intravascular ultrasound in a multicenter study. We measured coronary artery dimensions in 310 angiographically matched segments (175 were also fully matched by ultrasound criteria). At 1 year, lumen area changed by -1.8 +/- 3.7 mm(2) (p < 0.0001, 14% of baseline lumen area). Thirty-three percent of this luminal loss was due to intimal thickening and 67% to vessel shrinkage. Shrinkage also occurred (-0.9 +/- 3.2 mm(2), 7% of baseline total area) in segments free of detectable intimal disease at baseline and at 1 year. Using the mean baseline total vessel area (13.9 mm(2)) as the cutoff, we divided the cohort into the large and the small coronary-segment groups. The large-segment group (n = 176) shrank more (-2.6 +/- 4.4 vs. -0.03 +/- 2.8 mm(2), p < 0.0001), but intimal growth was similar in both groups (0.8 +/- 2.2 vs. 0.4 +/- 1.3 mm(2), p = not significant). Analysis of the 175 fully ultrasound matched sub-cohort showed similar results. Changes in intimal area, total vessel area, and lumen area were similar in segments with (n = 132) and segments without (n = 178) pre-existing donor disease. Despite overall shrinkage, change in total vessel area positively correlated with change in intimal area (r = 0.29, p < 0.0001). CONCLUSION: In large coronary segments, coronary artery shrinkage plays an important role in the loss of luminal diameter early after cardiac transplantation, whereas new intimal growth occurs in both large and small segments. Pre-existent donor disease does not aggravate these processes. Compensatory remodeling with increasing intimal growth retards the rate of lumen loss. As is intimal thickening, shrinkage and compensatory remodeling are important pathogenic mechanisms in transplant coronary artery disease.

The challenge of postoperative infections: does the surgeon make a difference?

Postoperative infections remain a challenge in many surgical procedures despite improved surgical technique and powerful antibiotics. The number of sepsis cases has tripled from 1979 to 1992 due to increased invasive procedures in older and immune-suppressed patients. Increasingly, in recent years, outbreaks of resistant pathogens have been published, provoking the question of how postoperative infections and resistant pathogens should be dealt with. Wound classification and risk stratification were developed to identify patients at risk for postoperative infection. However, other important intrinsic factors of the patient were not included, and further attempts have been made to increase sensitivity and specificity (eg, Study on the Efficacy of Nosocomial Infection Control project, National Nosocomial Infection Surveillance System score); the American Society of Anesthesiologists preoperative assessment score and the operation duration for specific procedures were introduced into the system as risk stratifiers. Advances in immunology have identified new ways in which the surgeon can moderate the immune response (eg, hemorrhage and blood transfusion-induced immune suppression). The increased rate of resistance in enterococci and staphylococci has refocused attention on infection control in surgery. However, there are recent reports from both sides of the Atlantic indicating that guidelines for infection control and antibiotic policy have not become reflected in standard procedures in many hospitals. New antibiotics may be developed, but resistance soon may follow. Sound techniques in surgery, with careful infection control and antibiotic policies, may be the only strategy to prevent further increases in resistance of pathogens in postoperative infections.

Influence of different autotransfusion devices on the quality of salvaged blood.

BACKGROUND: Cardiopulmonary bypass causes a systemic inflammatory response and impaired hemostasis. We investigated whether intraoperative blood salvage with the cardiotomy suction contributes to these alterations. Furthermore, an alternative autotransfusion device (Haemonetics cell-saving device) was examined. METHODS: In 10 patients, interleukin-6, interleukin-8, tumor necrosis factor-alpha, thrombin-antithrombin complex, plasmin-antiplasmin complex, free hemoglobin, and the percentage of CD62+ thrombocytes were determined in the systemic circulation during cardiopulmonary bypass, in the cardiotomy suction tube, and in the blood from the cell-saving device. Additionally, bacterial contamination was examined. RESULTS: Median levels of interleukin-6 (52 versus 10 microg/L; p = 0.005), interleukin-8 (26 versus 20 microg/L; p = 0.017), tumor necrosis factor-alpha (24 versus 1 microg/L; p = 0.005), thrombin-antithrombin complex (113 versus 43 microg/L; p = 0.005), plasmin-antiplasmin complex (566 versus 489 microg/L; p = 0.022), and free hemoglobin (61 versus 30 mg/dL; p = 0.005) were higher in the cardiotomy suction tube compared with the systemic circulation. After processing the blood from the cell-saving device, interleukin-8, thrombin-antithrombin complex, and free hemoglobin remained above reference range, and in 90% of the cases bacterial contamination was observed. CONCLUSIONS: Cardiotomy suction additionally contributes to the release of proinflammatory cytokines, activation of coagulation, and hemolysis. Because blood salvage with a Haemonetics cell-saving device led to normalization of some, but not all, parameters and bacterial contamination was common, the alternative use seems at least questionable.

Characterization of Listeria strains isolated from soft cheese.

Three soft cheeses were exposed to quantitative analysis for listeria and found to contain a large number of listeria. Thirty-five of the listeria strains isolated from the three cheeses were characterized by use of biochemical tests, serotyping, phagetyping and DNA restriction enzyme analysis. Seven isolates were identified as Listeria innocua and 28 as Listeria monocytogenes. Two to four different clones of L. monocytogenes could be identified from each cheese. In contrast, only one clone could be detected among the L. innocua isolates. From an epidemiological point of view the findings of different clones of L. monocytogenes in the same cheese emphasize the need for typing several listeria isolates from one and the same food sample. It is concluded that the best overview of the population of the listeria strains is obtained after direct plating of the sample followed by enumeration, isolation and extensive typing.

Communication skills and self-esteem in prevention of destructive behaviors.

This study demonstrates the long-range effectiveness of SAY IT STRAIGHT training as a school-based program for the prevention of destructive behaviors by comparing juvenile police offenders among trained and untrained 9th-12th graders for 1 1/2 years following training. In the 1984-85 school year, 357 of the 740 9th-12th graders in a southwestern town completed SAY IT STRAIGHT training. Participation was voluntary and required parental permission. During a five-month pretraining period which began with the first day of school, the number of juvenile police offenders was not significantly different among students who would eventually be trained or not be trained. During the following 7 months including summer vacation, there were significantly fewer offenders among the trained students. The following school year and summer vacation there were again significantly fewer offenders among the trained students. During the whole 1 1/2-year study, the untrained students had about 4.5 times as many criminal offenses as the trained students and their offenses were more severe. Finally, 9th, 10th, and 12th graders as well as 11th-grade females who had been trained showed a significant shift toward behavioral intentions reflecting a greater willingness to implement their constructive decisions and feel comfortable doing so. This study extends the applicability of SAY IT STRAIGHT training which previously has been reported to significantly reduce alcohol/drug-related school suspensions among 6th-8th graders.

[Infectious causes of diarrhea in Central Europe]. / Infektiöse Ursachen der Diarrhoe in Mitteleuropa.

In this paper the most isolated endemic and imported pathogens of diarrhea in Central Europe are demonstrated. Clinical symptoms, diagnosis and therapy and additional hygiene measures are described.

[Medicine behind bars. Illness is usual not grounds for modifying imprisonment]. / Medizin hinter Gittern. Krankheit ist meist kein Grund für eine Haftverschonung.

The article describes the possibilities of medical care in prison as exemplified by the Kassel 1 prison with its attached central hospital facility. The main areas of medical care covered there are the treatment of wounds, conservative treatment of fractures, ophthalmology, ENT, urology, dentistry and, via external consultant physicians, also internal medicine, pneumology, dermatology and gynecology. Such infections as hepatitis B and C, syphilis, and tuberculosis have a greater prevalence among prisoners--in contrast to other infections afflicting people housed under similar living conditions, such as in communal living facilities, which show no such increased prevalence. Furthermore, there is a relatively high percentage of injuries, including those that are self-inflicted. The problem of certifying a prisoner medically unfit to tolerate imprisonment is discussed.

Upgrade and benchmarking of a 4D treatment planning system for scanned ion beam therapy.

PURPOSE: Upgrade and benchmarking of a research 4D treatment planning system (4DTPS) suitable for realistic patient treatment planning and treatment simulations taking into account specific requirements for scanned ion beam therapy, i.e., modeling of dose heterogeneities due to interplay effects and range changes caused by patient motion and dynamic beam delivery. METHODS: The 4DTPS integrates data interfaces to 4D computed tomography (4DCT), deformable image registration and clinically used motion monitoring devices. The authors implemented a novel data model for 4D image segmentation using Boolean mask volume datasets and developed an algorithm propagating a manually contoured reference contour dataset to all 4DCT phases. They further included detailed treatment simulation and dose reconstruction functionality, based on the irregular patient motion and the temporal structure of the beam delivery. The treatment simulation functionality was validated against experimental data from irradiation of moving radiographic films in air, 3D moving ionization chambers in a water phantom, and moving cells in a biological phantom with a scanned carbon ion beam. The performance of the program was compared to results obtained with predecessor programs. RESULTS: The measured optical density distributions of the radiographic films were reproduced by the simulations to (-2 ± 12)%. Compared to earlier versions of the 4DTPS, the mean agreement improved by 2%, standard deviations were reduced by 7%. The simulated dose to the moving ionization chambers in water showed an agreement with the measured dose of (-1 ± 4)% for the typical beam configuration. The mean deviation of the simulated from the measured biologically effective dose determined via cell survival was (617 ± 538) mGy relative biological effectiveness corresponding to (10 ± 9)%. CONCLUSIONS: The authors developed a research 4DTPS suitable for realistic treatment planning on patient data and capable of simulating dose delivery to a moving patient geometry for scanned ion beams. The accuracy and reliability of treatment simulations improved considerably with respect to earlier versions of the 4DTPS.

Listeria monocytogenes--aspects of pathogenicity.

The genus Listeria includes different species of ubiquitary present gram-positive rod shaped bacteria. The species Listeria monocytogenes causes severe diseases like meningitis and meningoencephalitis in humans. Additional groups of syndromes associated with this microorganism are the listeriosis of the pregnant woman, mostly appearing as an abortion or septic premature birth and the meningitis of the newborn. Transmission of Listeria may occur on the oral route due to infected food like raw milk and cheese, raw meat or soil contaminated food like prepacked salads, respectively. The understanding of Listeria virulence was improved by different investigations employing cell cultures and molecular methods like knockout of genes encoding potential virulence factors. Nowadays the procedure of infection of cells is divided in four different parts: internalisation, escape from intracellular vacuole, nucleation of actin filaments and cell-to-cell spread. So called Internalins are produced by Listeria and are obviously needed for cell invasion. Listeria could escape intracellular vacuoles producing a hemolysin, Listeriolysin O, and proliferate inside the host cells. The surface bounded protein Actin A mediates the contact to the actin filament system of the host cell. This is important for the intracellular spread of Listeria. In the next step a cell-to-cell spread supported by phospholipase and lecithinase occurs. Despite the high incidence of contaminated food only a little incidence of listeriosis is observed. This may be explained in an indirect vaccination due to less virulent strains. However, the immune response of patients even with well documented listeriosis may be poor and causes false negative serological results sometimes. In this paper the know virulence factors of the interesting species L. monocytogenes are demonstrated and the course of infection is discussed.

[Coagulase gene polymorphism in Staphylococcus aureus--a new epidemiologic marker]. / Koagulasegenpolymorphismus bei Staphylococcus aureus--ein neuer epidemiologischer Marker.

Nosocomial infections with Staphylococcus aureus necessitate the prompt recognition of the infectious chain as well as a rapid investigation and exclusion of infectious sources. Conventional typification procedures (e.g. phage typing) and genotyping methods with pulsed-field gel electrophoresis (PFGE) are labor-intensive and time-consuming and can be performed only in a few laboratories. A new attractive typing technique for S. aureus utilizes the polymorphism of the coagulase (coa) gene as an epidemiological marker. This typing method is performed with primers, homologous to a conserved region within the coa gene, in order to amplify the sequences encoding the C-terminal region of this molecule. Since the number of repetitive sequences varies within the coa gene, the resulting PCR products of individual strains can be of different lengths. We have assessed the coa gene length polymorphism in 150 strains of S. aureus. By the sizes of the PCR products these strains could be categorized into 10 subgroups. AluI restriction analysis of the PCR products resulted in a significantly higher degree of discrimination. Since the repeated sequences, consisting of 81 base pairs, possess a high variability of the nucleotides, a characteristic restriction fragment length polymorphism (coa-RFLP) pattern is yielded. Overall, we could distinguish 64% of the clinical isolates by RFLP analysis; in strains sharing identical antibiograms, 56% could be distinguished. 46% oxacillin-resistant strains, some of which originated from epidemic outbreaks, could be discriminated by their RFLP pattern. Comparing these results with those obtained from the PFGE method, isolates which differed by their coagulase gene RFLP also differed by their PFGE patterns.(ABSTRACT TRUNCATED AT 250 WORDS)