154 research outputs found

    Efficient qubit detection using alkali earth metal ions and a double STIRAP process

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    We present a scheme for robust and efficient projection measurement of a qubit consisting of the two magnetic sublevels in the electronic ground state of alkali earth metal ions. The scheme is based on two stimulated Raman adiabatic passages (STIRAP) involving four partially coherent laser fields. We show how the efficiency depends on experimentally relevant parameters: Rabi frequencies, pulse widths, laser linewidths, one- and two-photon detunings, residual laser power, laser polarization and ion motion.Comment: 14 pages, 15 figure

    Are bone erosions detected by magnetic resonance imaging and ultrasonography true erosions? A comparison with computed tomography in rheumatoid arthritis metacarpophalangeal joints

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    The objective of the study was, with multidetector computed tomography (CT) as the reference method, to determine whether bone erosions in rheumatoid arthritis (RA) metacarpophalangeal (MCP) joints detected with magnetic resonance imaging (MRI) and ultrasonography (US), but not with radiography, represent true erosive changes. We included 17 RA patients with at least one, previously detected, radiographically invisible MCP joint MRI erosion, and four healthy control individuals. They all underwent CT, MRI, US and radiography of the 2nd to 5th MCP joints of one hand on the same day. Each imaging modality was evaluated for the presence of bone erosions in each MCP joint quadrant. In total, 336 quadrants were examined. The sensitivity, specificity and accuracy, respectively, for detecting bone erosions (with CT as the reference method) were 19%, 100% and 81% for radiography; 68%, 96% and 89% for MRI; and 42%, 91% and 80% for US. When the 16 quadrants with radiographic erosions were excluded from the analysis, similar values for MRI (65%, 96% and 90%) and US (30%, 92% and 80%) were obtained. CT and MRI detected at least one erosion in all patients but none in control individuals. US detected at least one erosion in 15 patients, however, erosion-like changes were seen on US in all control individuals. Nine patients had no erosions on radiography. In conclusion, with CT as the reference method, MRI and US exhibited high specificities (96% and 91%, respectively) in detecting bone erosions in RA MCP joints, even in the radiographically non-erosive joints (96% and 92%). The moderate sensitivities indicate that even more erosions than are seen on MRI and, particularly, US are present. Radiography exhibited high specificity (100%) but low sensitivity (19%). The present study strongly indicates that bone erosions, detected with MRI and US in RA patients, represent a loss of calcified tissue with cortical destruction, and therefore can be considered true bone erosions

    Preoperative CT versus diffusion weighted magnetic resonance imaging of the liver in patients with rectal cancer:a prospective randomized trial

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    Introduction. Colorectal cancer is one of the most frequent cancers in the world and liver metastases are seen in up to 19% of patients with colorectal cancers. Detection of liver metastases is not only vital for sufficient treatment and survival, but also for a better estimation of prognosis. The aim of this study was to evaluate the feasibility of diffusion weighted MRI of the liver as part of a combined MR evaluation of patients with rectal cancers and compare it with the standard preoperative evaluation of the liver with CT.Methods. Consecutive patients diagnosed with rectal cancers were asked to participate in the study. Preoperative CT and diffusion weighted MR (DWMR) were compared to contrast enhanced laparoscopic ultrasound (CELUS).Results. A total of 35 patients were included, 15 patients in Group-1 having the standard CT evaluation of the liver and 20 patients in Group-2 having the standard CT evaluation of the liver and DWMR of the liver. Compared with CELUS, the per-patient sensitivity/specificity was 50/100% for CT, and for DWMR: 100/94% and 100/100% for Reader 1 and 2, respectively. The per-lesion sensitivity of CT and DWMR were 17% and 89%, respectively compared with CELUS. Furthermore, one patient had non-resectable metastases after DWMR despite being diagnosed with resectable metastases after CT. Another patient was diagnosed with multiple liver metastases during CELUS, despite a negative CT-scan.Discussion. DWMR is feasible for preoperative evaluation of liver metastases. The current standard preoperative evaluation with CT-scan results in disadvantages like missed metastases and futile operations. We recommend that patients with rectal cancer, who are scheduled for MR of the rectum, should have a DWMR of the liver performed at the same time

    HldE Is Important for Virulence Phenotypes in Enterotoxigenic <i>Escherichia coli</i>

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    Enterotoxigenic Escherichia coli (ETEC) is one of the most common causes of diarrheal illness in third world countries and it especially affects children and travelers visiting these regions. ETEC causes disease by adhering tightly to the epithelial cells in a concerted effort by adhesins, flagella, and other virulence-factors. When attached ETEC secretes toxins targeting the small intestine host-cells, which ultimately leads to osmotic diarrhea. HldE is a bifunctional protein that catalyzes the nucleotide-activated heptose precursors used in the biosynthesis of lipopolysaccharide (LPS) and in post-translational protein glycosylation. Both mechanisms have been linked to ETEC virulence: Lipopolysaccharide (LPS) is a major component of the bacterial outer membrane and is needed for transport of heat-labile toxins to the host cells, and ETEC glycoproteins have been shown to play an important role for bacterial adhesion to host epithelia. Here, we report that HldE plays an important role for ETEC virulence. Deletion of hldE resulted in markedly reduced binding to the human intestinal cells due to reduced expression of colonization factor CFA/I on the bacterial surface. Deletion of hldE also affected ETEC motility in a flagella-dependent fashion. Expression of both colonization factors and flagella was inhibited at the level of transcription. In addition, the hldE mutant displayed altered growth, increased biofilm formation and clumping in minimal growth medium. Investigation of an orthogonal LPS-deficient mutant combined with mass spectrometric analysis of protein glycosylation indicated that HldE exerts its role on ETEC virulence both through protein glycosylation and correct LPS configuration. These results place HldE as an attractive target for the development of future antimicrobial therapeutics

    The phenotypic presentation of adult individuals with SLC6A1-related neurodevelopmental disorders

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    IntroductionSLC6A1 is one of the most common monogenic causes of epilepsy and is a well-established cause of neurodevelopmental disorders. SLC6A1-neurodevelopmental disorders have a consistent phenotype of mild to severe intellectual disability (ID), epilepsy, language delay and behavioral disorders. This phenotypic description is mainly based on knowledge from the pediatric population.MethodHere, we sought to describe patients with SLC6A1 variants and age above 18 years through the ascertainment of published and unpublished patients. Unpublished patients were ascertained through international collaborations, while previously published patients were collected through a literature search.ResultsA total of 15 adult patients with SLC6A1 variants were included. 9/13 patients had moderate to severe ID (data not available in two). Epilepsy was prevalent (11/15) with seizure types such as absence, myoclonic, atonic, and tonic–clonic seizures. Epilepsy was refractory in 7/11, while four patients were seizure free with lamotrigine, valproate, or lamotrigine in combination with valproate. Language development was severely impaired in five patients. Behavioral disorders were reported in and mainly consisted of autism spectrum disorders and aggressive behavior. Schizophrenia was not reported in any of the patients.DiscussionThe phenotype displayed in the adult patients presented here resembled that of the pediatric cohort with ID, epilepsy, and behavioral disturbances, indicating that the phenotype of SLC6A1-NDD is consistent over time. Seizures were refractory in &gt;60% of the patients with epilepsy, indicating the lack of targeted treatment in SLC6A1-NDDs. With increased focus on repurposing drugs and on the development of new treatments, hope is that the outlook reflected here will change over time. ID appeared to be more severe in the adult patients, albeit this might reflect a recruitment bias, where only patients seen in specialized centers were included or it might be a feature of the natural history of SLC6A1-NDDs. This issue warrants to be explored in further studies in larger cohorts

    Albumin administration in septic shock-Protocol for post-hoc analyses of data from a multicentre RCT.

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    BACKGROUND Intravenous (IV) albumin is suggested for patients with septic shock who have received large amounts of IV crystalloids; a conditional recommendation based on moderate certainty of evidence. Clinical variation in the administration of IV albumin in septic shock may exist according to patient characteristics and location. METHODS This is a protocol and statistical analysis plan for a post-hoc secondary study of the Conservative versus Liberal Approach to Fluid Therapy of Septic Shock in Intensive Care (CLASSIC) RCT of 1554 adult ICU patients with septic shock. We will assess if specific baseline characteristics or trial site are associated with the administration of IV albumin during ICU stay using Cox models with competing events. All models will be adjusted for the treatment allocation in CLASSIC (restrictive vs. standard IV fluid), and all analyses will consider competing events (death, ICU discharge and loss-to-follow-up). We will present results as hazard ratios with 95% confidence intervals and p-values for the associations of baseline characteristics or site with IV albumin administration. Between-group differences (interactions) will be assessed using p-values from likelihood ratio tests. All results will be considered exploratory only. DISCUSSION This secondary study of the CLASSIC RCT may yield important insight into potential practice variation in the administration of albumin in septic shock

    Robustness of genome-wide scanning using archived dried blood spot samples as a DNA source

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    <p>Abstract</p> <p>Background</p> <p>The search to identify disease-susceptible genes requires access to biological material from numerous well-characterized subjects. Archived residual dried blood spot (DBS) samples, also known as Guthrie cards, from national newborn screening programs may provide a DNA source for entire populations. Combined with clinical information from medical registries, DBS samples could provide a rich source for productive research. However, the amounts of DNA which can be extracted from these precious samples are minute and may be prohibitive for numerous genotypings. Previously, we demonstrated that DBS DNA can be whole-genome amplified and used for reliable genetic analysis on different platforms, including genome-wide scanning arrays. However, it remains unclear whether this approach is workable on a large sample scale. We examined the robustness of using DBS samples for whole-genome amplification following genome-wide scanning, using arrays from Illumina and Affymetrix.</p> <p>Results</p> <p>This study is based on 4,641 DBS samples from the Danish Newborn Screening Biobank, extracted for three separate genome-wide association studies. The amount of amplified DNA was significantly (P < 0.05) affected by the year of storage and storage conditions. Nine (0.2%) DBS samples failed whole-genome amplification. A total of 4,586 (98.8%) samples met our criterion of success of a genetic call-rate above 97%. The three studies used different arrays, with mean genotyping call-rates of 99.385% (Illumina Infinium Human610-Quad), 99.722% (Illumina Infinium HD HumanOmni1-Quad), and 99.206% (Affymetrix Axiom Genome-Wide CEU). We observed a concordance rate of 99.997% in the 38 methodological replications, and 99.999% in the 27 technical replications. Handling variables such as time of storage, storage conditions and type of filter paper were shown too significantly (P < 0.05) affect the genotype call-rates in some of the arrays, although the effect was minimal.</p> <p>Conclusion</p> <p>Our study indicates that archived DBS samples from the Danish Newborn Screening Biobank represent a reliable resource of DNA for whole-genome amplification and subsequent genome-wide association studies. With call-rates equivalent to high quality DNA samples, our results point to new opportunities for using the neonatal biobanks available worldwide in the hunt for genetic components of disease.</p
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