493 research outputs found

    Entangling two distant nanocavities via a waveguide

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    In this paper, we investigate the generation of continuous variable entanglement between two spatially-separate nanocavities mediated by a coupled resonator optical waveguide in photonic crystals. By solving the exact dynamics of the cavity system coupled to the waveguide, the entanglement and purity of the two-mode cavity state are discussed in detail for the initially separated squeezing inputs. It is found that the stable and pure entangled state of the two distant nanocavities can be achieved with the requirement of only a weak cavity-waveguide coupling when the cavities are resonant with the band center of the waveguide. The strong couplings between the cavities and the waveguide lead to the entanglement sudden death and sudden birth. When the frequencies of the cavities lie outside the band of the waveguide, the waveguide-induced cross frequency shift between the cavities can optimize the achievable entanglement. It is also shown that the entanglement can be easily manipulated through the changes of the cavity frequencies within the waveguide band.Comment: 8 pages, 8 figure

    Photodegradation of 1,3,5-trichlorobenzene in aqueous surfactant solutions

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    The original publication is available at www.springerlink.comArticleBULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY. 74(2): 365-372 (2005)journal articl

    Optimization of quasi-normal eigenvalues for Krein-Nudelman strings

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    The paper is devoted to optimization of resonances for Krein strings with total mass and statical moment constraints. The problem is to design for a given α∈R\alpha \in \R a string that has a resonance on the line \alpha + \i \R with a minimal possible modulus of the imaginary part. We find optimal resonances and strings explicitly.Comment: 9 pages, these results were extracted in a slightly modified form from the earlier e-print arXiv:1103.4117 [math.SP] following an advise of a journal's refere

    Risk factors of fracture following curettage for bone giant cell tumors of the extremities

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    Background: Following curettage of giant cell tumor of bone (GCTB), it is common to fill the cavity with polymethylmethacrylate (PMMA) bone cement, bone allograft, or artificial bone to maintain bone strength; however, there is a 2–14% risk of postoperative fractures. We conducted this retrospective study to clarify the risk factors for fractures after curettage for GCTB of the extremities. Methods: This study included 284 patients with GCTBs of the extremities who underwent curettage at our institutions between 1980 and 2018 after excluding patients whose cavities were not filled with anything or who had additional plate fixation. The tumor cavity was filled with PMMA bone cement alone (n = 124), PMMA bone cement and bone allograft (n = 81), bone allograft alone (n = 63), or hydroxyapatite graft alone (n = 16). Results: Fractures after curettage occurred in 10 (3.5%) patients, and the median time from the curettage to fracture was 3.5 months (interquartile range [IQR], 1.8–8.3 months). The median postoperative follow-up period was 86.5 months (IQR, 50.3–118.8 months). On univariate analysis, patients who had GCTB of the proximal or distal femur (1-year fracture-free survival, 92.5%; 95% confidence interval [CI]: 85.8–96.2) presented a higher risk for postoperative fracture than those who had GCTB at another site (100%; p = 0.0005). Patients with a pathological fracture at presentation (1-year fracture-free survival, 88.2%; 95% CI: 63.2–97.0) presented a higher risk for postoperative fracture than those without a pathological fracture at presentation (97.8%; 95% CI: 95.1–99.0; p = 0.048). Patients who received bone grafting (1-year fracture-free survival, 99.4%; 95% CI: 95.7–99.9) had a lower risk of postoperative fracture than those who did not receive bone grafting (94.4%; 95% CI: 88.7–97.3; p = 0.003). Conclusions: For GCTBs of the femur, especially those with pathological fracture at presentation, bone grafting after curettage is recommended to reduce the risk of postoperative fracture. Additional plate fixation should be considered when curettage and cement filling without bone grafting are performed in patients with GCTB of the femur. This should be specially performed for those patients with a pathological fracture at presentation

    A case of wound dual infection with Pasteurella dagmatis and Pasteurella Canis resulting from a dog bite - limitations of Vitek-2 system in exact identification of Pasteurella species

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    <p>Abstract</p> <p>Background</p> <p><it>Pasteurella </it>species, widely known as indigenous orgganisms in the oral and gastrointestinal floras of many wild and domestic animals, are important pathogens in both animals and humans. Human infections due to <it>Pasteurella </it>species are in most cases associated with infected injuries following animal bites. We encountered a rare case of dual infections caused by different two <it>Pasteurella </it>species occurred in a previously healthy 25-year-old female sustaining injury by a dog-bite.</p> <p>Methodology</p> <p>Exudates from the open wound of her dog-bite site, together with the saliva of the dog were submitted for bacteriological examination. Predominantly appearing grayish-white smooth colonies with almost the same colonial properties but slightly different glistening grown on chocolate and sheep blood agar plates were characterized morphologically by Gram's stain, biochemically by automated instrument using Vitek 2 system using GN cards together with commercially available kit system, ID-Test HN-20 rapid panels, and genetically by sequencing the 16S rRNA genes of the organism using a Taq DyeDeoxy Terminator Cycle Sequencing and a model 3100 DNA sequencer instrument.</p> <p>Results</p> <p>The causative isolates from the dog-bite site were finally identified as <it>P</it>. <it>canis </it>and <it>P</it>. <it>dagmatis </it>from the findings of the morphological, cultural, and biochemical properties together with the comparative sequences of the 16S rRNA genes. Both the isolates were highly susceptible to many antibiotics and the patient was successfully treated with the administration of so-called the first generation cephalosporin, cefazolin followed by so-called the third generation cephalosporin, cefcapene pivoxil. The isolate from the dog was subsequently identified as <it>P</it>. <it>canis</it>, the same species as the isolate from the patient.</p> <p>Conclusions</p> <p>To the best of our knowledge, this was the second report of a dual infection with <it>Pasteurella </it>species consisting of <it>P</it>. <it>dagmatis </it>and <it>P. canis </it>resulting from a dog-bite, followed by the first report of dual infections due to <it>P</it>. <it>dagmatis </it>and <it>P. multocida </it>in 1988. Our isolate finally identified as <it>P</it>. <it>dagmatis </it>was misidentified as <it>P</it>. <it>pneumotripica by </it>means of the Vitek 2 system. The species name "<it>P</it>. <it>dagmatis" </it>was not included in the database of the system. It is also important for routine clinical microbiology laboratories to know the limitation of the automated Vitek 2 system for the accurate identification of <it>Pasteurella </it>species especially <it>P</it>. <it>dagmatis</it>. It should be emphasized that there still exists much room for improvement in Vitek 2 system. Significant improvement of Vitek 2 system especially in the identification of <it>Pasteurella </it>species is urgently desired.</p

    Upfront surgery is not advantageous compared to more conservative treatments such as observation or medical treatment for patients with desmoid tumors

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    Background: This study compared the clinical and functional outcomes of patients initially treated with observation or medical treatment with those of patients treated with local treatment (surgery alone or surgery with adjuvant radiotherapy) to confirm whether observation or medical treatment is an appropriate first-line management approach for patients with desmoid tumors. Methods: We retrospectively reviewed the medical records of 99 patients with histologically confirmed primary desmoid tumors treated between 1978 and 2018. The median follow-up period was 57 months. We evaluated event-free survival, defined as the time interval from the date of initial diagnosis to the date of specific change in treatment strategy or recurrence or the last follow-up. Results: An event (specific change in treatment strategy or recurrence) occurred in 28 patients (28.3%). No significant difference in event-free survival was found between the first-line observation/medical treatment and local treatment groups (p = 0.509). The median Musculoskeletal Tumor Society score of the patients treated with first-line local treatment was 29 (interquartile range [IQR], 23\u201330), whereas that of the patients managed with first-line observation or medical treatment was 21 (IQR, 19\u201329.5). First-line observation or medical treatment was more frequently chosen for larger tumors (p = 0.045). In the patients treated with local treatment, local recurrence was not related to the surgical margin (p = 0.976). Conclusion: Upfront surgery is not advantageous compared to more conservative treatments such as observation or medical treatment for patients with desmoid tumors

    Use of Cryopreserved Osteogenic Matrix Cell Sheets for Bone Reconstruction

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    Abstract Skeletal diseases, such as nonunion and osteonecrosis, are now treatable with tissue engineering techniques. Single cell sheets called osteogenic matrix cell sheets (OMCSs) grown from cultured bone marrow-derived mesenchymal stem cells show high osteogenic potential; however, long preparation times currently limit their clinical application. Here, we report a cryopreservation OMCS transplantation method that shortens OMCS preparation time. Cryopreserved rat OMCSs were prepared using slow-and rapid-freezing methods, thawed, and subsequently injected scaffold-free into subcutaneous sites. Rapid-and slow-frozen OMCSs were also transplanted directly to the femur bone at sites of injury. Slow-freezing resulted in higher cell viability than rapid freezing, yet all two cryopreservation methods yielded OMCSs that survived and formed bone tissue. In the rapid-and slow-freezing groups, cortical gaps were repaired and bone continuity was observed within 6 weeks of OMCS transplantation. Moreover, while no significant difference was found in osteocalcin expression between the three experimental groups, the biomechanical strength of femurs treated with slow-frozen OMCSs was significantly greater than those of non-transplant at 6 weeks post-injury. Collectively, these data suggest that slow-frozen OMCSs have superior osteogenic potential and are better suited to produce a mineralized matrix and repair sites of bone injury

    Modelling of photonic wire Bragg Gratings

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    Some important properties of photonic wire Bragg grating structures have been investigate. The design, obtained as a generalisation of the full-width gap grating, has been modelled using 3D finite-difference time-domain simulations. Different types of stop-band have been observed. The impact of the grating geometry on the lowest order (longest wavelength) stop-band has been investigated - and has identified deeply indented configurations where reduction of the stop-bandwidth and of the reflectivity occurred. Our computational results have been substantially validated by an experimental demonstration of the fundamental stop-band of photonic wire Bragg gratings fabricated on silicon-on-insulator material. The accuracy of two distinct 2D computational models based on the effective index method has also been studied - because of their inherently much greater rapidity and consequent utility for approximate initial designs. A 2D plan-view model has been found to reproduce a large part of the essential features of the spectral response of full 3D models

    Osteogenic extracellular matrix sheet for bone tissue regeneration

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    The application of extracellular matrix (ECM) sheets without a scaffold is not extensively reported in bone regenerative medicine. The aim of the present study was to demonstrate that an osteogenic ECM sheet (OECMS) can retain ECM integrity and growth factors to enhance bone formation in a rat non-union model. OECMS was produced from osteogenic cell sheets (OCS). Collagen and growth factor [bone morphogenetic protein 2 (BMP-2), vascular endothelial growth factors (VFGFs), basic fibroblast growth factor (bFGF) and transforming growth factor β1 (TGF-β1)] concentrations in the OECMS were quantified by enzyme-linked immunosorbent assay (ELISA). Next, hydroxyapatite (HA) constructs combined with OECMSs were implanted subcutaneously into the rats' backs to evaluate their osteoinductive capacity by histological evaluation. In addition, OECMSs were implanted in a rat femoral non-union model. 18 male Fischer 344 inbred rats were divided into OECMS and control groups. Fracture healing was evaluated by radiological and histological analyses at 2, 5 and 8 weeks and biological analysis at 8 weeks. Collagen I and growth factors were retained in the OECMSs. Osteoid formation was identified in the HA combined with OECMS at 4 weeks. Enhanced bone regeneration at the non-union of the OECMS group was confirmed at 5 and 8 weeks. Biomechanical testing revealed a significantly higher maximum bending load in the OECMS group as compared to the control group at 8 weeks. The results demonstrated that OECMS retained BMP-2 and TGF-β1 and high osteoinductive and osteoconductive capacity. As such, OECMS represents a potential new scaffold-free material for bone tissue engineering
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