Structure of smectic defect cores: an X-ray study of 8CB liquid crystal ultra-thin films

We study the structure of very thin liquid crystal films frustrated by antagonistic anchorings in the smectic phase. In a cylindrical geometry, the structure is dominated by the defects for film thicknesses smaller than 150 nm and the detailed topology of the defects cores can be revealed by x-ray diffraction. They appear to be split in half tube-shaped Rotating Grain Boundaries (RGB). We determine the RGB spatial extension and evaluate its energy per unit line. Both are significantly larger than the ones usually proposed in the literatureComment: 4 page

Efficacy and safety of electrochemotherapy combined with peritumoral IL-12 gene electrotransfer of canine mast cell tumours

Electrochemotherapy combined with peritumoral interleukin-12 (IL-12) gene electrotransfer was used for treatment of mast cell tumours in 18 client-owned dogs. Local tumour control, recurrence rate, as well as safety of combined therapy were evaluated. One month after the therapy, no side effects were recorded and good local tumour control was observed with high complete responses rate which even increased during the observation period to 72%. IL-12 gene electrotransfer resulted in 78% of patients with detectable serum IFN- and/or IL-12 levels. In the treated tumours vascular changes as well as minimal T-lymphocytes infiltration was observed. After 1week, the plasmid DNA was not detected intra- or peritumorally and no horizontal gene transfer was observed. In summary, our study demonstrates high antitumour efficacy of electrochemotherapy combined with IL-12 electrotransfer, which also prevented recurrences or distant metastases, as well as its safety and feasibility in treatment of canine mast cell tumours

Emergence of quinolone resistance among extended-spectrum beta-lactamase-producing Enterobacteriaceae in the Central African Republic: genetic characterization

<p>Abstract</p> <p>Background</p> <p>Cross-resistance to quinolones and beta-lactams is frequent in <it>Enterobacteriaceae</it>, due to the wide use of these antibiotics clinically and in the food industry. Prescription of one of these categories of antibiotic may consequently select for bacteria resistant to both categories. Genetic mechanisms of resistance may be secondary to a chromosomal mutation located in quinolone resistance determining region of DNA gyrase or topoisomerase IV or to a plasmid acquisition. The insertion sequence IS<it>CR1 </it>is often associated with <it>qnr </it>and may favour its dissemination in Gram-negative bacteria. The aim of this study was to determine the genetic mechanism of quinolone resistance among extended-spectrum beta-lactamase-producing <it>Enterobacteriaceae </it>strains in the Central African Republic.</p> <p>Findings</p> <p>Among seventeen ESBL-producing <it>Enterobacteriaceae </it>isolated from urine, pus or stool between January 2003 and October 2005 in the Central African Republic, nine were resistant to ciprofloxacin (seven from community patients and two from hospitalized patients). The ESBL were previously characterized as CTX-M-15 and SHV-12. Susceptibility to nalidixic acid, norfloxacin and ciprofloxacin, and the minimal inhibitory concentrations of these drugs were determined by disc diffusion and agar dilution methods, respectively. The presence of plasmid-borne IS<it>CR1-qnrA </it>region was determined by PCR and amplicons, if any, were sent for sequencing. Quinolone resistance determining region of DNA gyrase <it>gyrA </it>gene was amplified by PCR and then sequenced for mutation characterization. We found that all CTX-M-producing strains were resistant to the tested quinolones. All the isolates had the same nucleotide mutation at codon 83 of <it>gyrA</it>. Two <it>Escherichia coli </it>strains with the highest MICs were shown to harbour an IS<it>CR1-qnrA1 </it>sequence. This genetic association might favour dissemination of resistance to quinolone and perhaps other antibiotics among <it>Enterobacteriaceae</it>.</p> <p>Conclusions</p> <p>This study shows that at least two mechanisms might explain the emerging resistance of <it>Enterobacteriaceae </it>to quinolones in the CAR. Beside the classical topoisomerase mutation, the cause may be acquisition of a plasmid-borne <it>qnrA1</it>. Clinicians and bacteriologists should be made aware of possible dissemination of IS<it>CR1-qnrA1 </it>among <it>Enterobacteriacae</it>.</p

NEWS AND NOTES 1994, VOL.4, NO.16

https://digitalcommons.rockefeller.edu/news_and_notes_1994/1002/thumbnail.jp

Deep learning models for automatic tumor segmentation and total tumor volume assessment in patients with colorectal liver metastases

Background: We developed models for tumor segmentation to automate the assessment of total tumor volume (TTV) in patients with colorectal liver metastases (CRLM). Methods: In this prospective cohort study, pre- and post-systemic treatment computed tomography (CT) scans of 259 patients with initially unresectable CRLM of the CAIRO5 trial (NCT02162563) were included. In total, 595 CT scans comprising 8,959 CRLM were divided into training (73%), validation (6.5%), and test sets (21%). Deep learning models were trained with ground truth segmentations of the liver and CRLM. TTV was calculated based on the CRLM segmentations. An external validation cohort was included, comprising 72 preoperative CT scans of patients with 112 resectable CRLM. Image segmentation evaluation metrics and intraclass correlation coefficient (ICC) were calculated. Results: In the test set (122 CT scans), the autosegmentation models showed a global Dice similarity coefficient (DSC) of 0.96 (liver) and 0.86 (CRLM). The corresponding median per-case DSC was 0.96 (interquartile range [IQR] 0.95–0.96) and 0.80 (IQR 0.67–0.87). For tumor segmentation, the intersection-over-union, precision, and recall were 0.75, 0.89, and 0.84, respectively. An excellent agreement was observed between the reference and automatically computed TTV for the test set (ICC 0.98) and external validation cohort (ICC 0.98). In the external validation, the global DSC was 0.82 and the median per-case DSC was 0.60 (IQR 0.29–0.76) for tumor segmentation. Conclusions: Deep learning autosegmentation models were able to segment the liver and CRLM automatically and accurately in patients with initially unresectable CRLM, enabling automatic TTV assessment in such patients. Relevance statement: Automatic segmentation enables the assessment of total tumor volume in patients with colorectal liver metastases, with a high potential of decreasing radiologist’s workload and increasing accuracy and consistency. Key points: • Tumor response evaluation is time-consuming, manually performed, and ignores total tumor volume. • Automatic models can accurately segment tumors in patients with colorectal liver metastases. • Total tumor volume can be accurately calculated based on automatic segmentations. Graphical Abstract: [Figure not available: see fulltext.]

Stability and metastability in nematic glasses: a computational study

The influence of randomly distributed impurities on liquid crystal (LC) orientational ordering is studied using a simple Lebwohl-Lasher type lattice model in two (d=2) and three (d=3) dimensions. The impurities of concentration p impose a random anisotropy field-type of disorder of strength w to the LC nematic phase. Orientational correlations can be well presented by a single coherence length for a weak enough w. We show that the Imry-Ma scaling prediction w holds true if the LC configuration is initially quenched from the isotropic phase. For other initial configurations the scaling is in general not obeye

Biology teaching in upper secondary schools: Comparative study between Slovenia and Turkey

In recent times exchange of students between countries became popular. As teacher educators we have to prepare our students to teach efficiently in fast changing world and to be effective in future careers with educational technologies not yet discovered. Because of mobility and especially fast development of information and communication technologies some teaching competences became global but shaped with local circumstances. So to enhance cross border and cross cultural cooperation in teacher education between Slovenia and Turkey we have to identify if our students share basic experiences and attitudes toward Biology at their pre-university education to prepare appropriate teaching strategies to be used in effective teaching. From our study we can make a conclusion that even if both countries had different history, traditions, culture, dominant religion, differences in biology teaching are surprisingly small. So if we plan students exchange they will easily understand each other when talking about their experiences in high school, so the only barrier can be language in which courses are offered. © Sila Science