3D tomography of cells in micro-channels

We combine confocal imaging, microfluidics and image analysis to record 3D-images of cells in flow. This enables us to recover the full 3D representation of several hundred living cells per minute. Whereas 3D confocal imaging has thus far been limited to steady specimen, we overcome this restriction and present a method to access the 3D shape of moving objects. The key of our principle is a tilted arrangement of the micro-channel with respect to the focal plane of the microscope. This forces cells to traverse the focal plane in an inclined manner. As a consequence, individual layers of passing cells are recorded which can then be assembled to obtain the volumetric representation. The full 3D information allows for a detailed comparisons with theoretical and numerical predictions unfeasible with e.g.\ 2D imaging. Our technique is exemplified by studying flowing red blood cells in a micro-channel reflecting the conditions prevailing in the microvasculature. We observe two very different types of shapes: `croissants' and `slippers'. Additionally, we perform 3D numerical simulations of our experiment to confirm the observations. Since 3D confocal imaging of cells in flow has not yet been realized, we see high potential in the field of flow cytometry where cell classification thus far mostly relies on 1D scattering and fluorescence signals

Atomic and nuclear physics with stored particles in ion traps

Trapping and cooling techniques play an increasingly important role in many areas of science. This review concentrates on recent applications of ion traps installed at accelerator facilities to atomic and nuclear physics such as mass spectrometry of radioactive isotopes, weak interaction studies, symmetry tests, determination of fundamental constants, laser spectroscopy, and spectroscopy of highly-charged ions. In addition, ion traps are proven to be extremely efficient devices for (radioactive) ion beam manipulation as, for example, retardation, accumulation, cooling, beam cleaning, charge-breeding, and bunching

Epidemiological evidence of cervical intraepithelial neoplasia without the presence of human papillomavirus.

The aim of this paper was to provide epidemiological evidence to support the notion that cervical intraepithelial neoplasia (CIN) without human papillomavirus (HPV) is a true entity. If a diagnosis of HPV-negative cervical neoplasia is erroneous, one would not expect there to be any differences in risk factors between HPV-positive and HPV-negative patients. Patients at a gynaecological outpatient clinic of a university hospital [a total of 265 consecutive women with dyskaryotic cervical smears who were subsequently diagnosed with CIN I (n=37), CIN II (n=48) or CIN III (n=180)] completed a structured questionnaire regarding smoking habits and sexual history. Analysis of an endocervical swab for Chlamydia trachomatis, analysis of a cervical scrape for HPV, and morphological examination of cervical biopsy specimens were also performed. HPV was found in 205 (77.4%) out of the 265 women. Univariate analysis showed that current age (P=0.02), current smoking behaviour (P=0.002) and the number of sexual partners (P=0.02) were significantly associated with the presence of HPV. Age at first sexual intercourse, a past history of venereal disease or genital warts, and current infection with Chlamydia trachomatis were not associated with the presence of HPV. Using multivariate logistic regression analysis, the number of sexual partners and current smoking behaviour showed an independent significant association with HPV. HPV-negative and HPV-positive CIN patients differ with respect to the risk factors for HPV. These findings suggest that HPV-negative CIN is a separate true entity

HITRAP: A facility at GSI for highly charged ions

An overview and status report of the new trapping facility for highly charged ions at the Gesellschaft fuer Schwerionenforschung is presented. The construction of this facility started in 2005 and is expected to be completed in 2008. Once operational, highly charged ions will be loaded from the experimental storage ring ESR into the HITRAP facility, where they are decelerated and cooled. The kinetic energy of the initially fast ions is reduced by more than fourteen orders of magnitude and their thermal energy is cooled to cryogenic temperatures. The cold ions are then delivered to a broad range of atomic physics experiments.Comment: 8 pages, 11 figure

Modeling the unified measurement uncertainty of deflectometric and plenoptic 3-D sensors

In this paper we propose new models of two complementary optical sensors to obtain 2.5-D measurements of opaque surfaces: a deflectometric and a plenoptic sensor. The deflectometric sensor uses active triangulation and works best on specular surfaces, while the plenoptic sensor uses passive triangulation and works best on textured, diffusely reflecting surfaces. We propose models to describe the measurement uncertainties of the sensors for specularly to diffusely reflecting surfaces under consideration of typical disturbances like ambient light or vibration. The predicted measurement uncertainties of both sensors can be used to obtain optimized measurements uncertainties for varying surface properties on the basis of a combined sensor system. The models are validated exemplarily based on real measurements.</p

Predicting COPD 1-year mortality using prognostic predictors routinely measured in primary care.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a major cause of mortality. Patients with advanced disease often have a poor quality of life, such that guidelines recommend providing palliative care in their last year of life. Uptake and use of palliative care in advanced COPD is low; difficulty in predicting 1-year mortality is thought to be a major contributing factor. METHODS: We identified two primary care COPD cohorts using UK electronic healthcare records (Clinical Practice Research Datalink). The first cohort was randomised equally into training and test sets. An external dataset was drawn from a second cohort. A risk model to predict mortality within 12 months was derived from the training set using backwards elimination Cox regression. The model was given the acronym BARC based on putative prognostic factors including body mass index and blood results (B), age (A), respiratory variables (airflow obstruction, exacerbations, smoking) (R) and comorbidities (C). The BARC index predictive performance was validated in the test set and external dataset by assessing calibration and discrimination. The observed and expected probabilities of death were assessed for increasing quartiles of mortality risk (very low risk, low risk, moderate risk, high risk). The BARC index was compared to the established index scores body mass index, obstructive, dyspnoea and exacerbations (BODEx), dyspnoea, obstruction, smoking and exacerbations (DOSE) and age, dyspnoea and obstruction (ADO). RESULTS: Fifty-four thousand nine hundred ninety patients were eligible from the first cohort and 4931 from the second cohort. Eighteen variables were included in the BARC, including age, airflow obstruction, body mass index, smoking, exacerbations and comorbidities. The risk model had acceptable predictive performance (test set: C-index = 0.79, 95% CI 0.78-0.81, D-statistic = 1.87, 95% CI 1.77-1.96, calibration slope = 0.95, 95% CI 0.9-0.99; external dataset: C-index = 0.67, 95% CI 0.65-0.7, D-statistic = 0.98, 95% CI 0.8-1.2, calibration slope = 0.54, 95% CI 0.45-0.64) and acceptable accuracy predicting the probability of death (probability of death in 1 year, n high-risk group, test set: expected = 0.31, observed = 0.30; external dataset: expected = 0.22, observed = 0.27). The BARC compared favourably to existing index scores that can also be applied without specialist respiratory variables (area under the curve: BARC = 0.78, 95% CI 0.76-0.79; BODEx = 0.48, 95% CI 0.45-0.51; DOSE = 0.60, 95% CI 0.57-0.61; ADO = 0.68, 95% CI 0.66-0.69, external dataset: BARC = 0.70, 95% CI 0.67-0.72; BODEx = 0.41, 95% CI 0.38-0.45; DOSE = 0.52, 95% CI 0.49-0.55; ADO = 0.57, 95% CI 0.54-0.60). CONCLUSION: The BARC index performed better than existing tools in predicting 1-year mortality. Critically, the risk score only requires routinely collected non-specialist information which, therefore, could help identify patients seen in primary care that may benefit from palliative care