Evolving morphotropic phase boundary in lead-free (Bi1/2Na1/2)TiO3–BaTiO3 piezoceramics

The correlation between structure and electrical properties of lead-free (1-x)(Bi(1/2)Na(1/2))TiO(3)-xBaTiO(3) (BNT-100xBT) polycrystalline piezoceramics was investigated systematically by in situ synchrotron diffraction technique, combined with electrical property characterization. It was found that the morphotropic phase boundary (MPB) between a rhombohedral and a tetragonal phase evolved into a morphotropic phase region with electric field. In the unpoled material, the MPB was positioned at the transition from space group R3m to P4mm (BNT-11BT) with optimized permittivity throughout a broad single-phase R3m composition regime. Upon poling, a range of compositions from BNT-6BT to BNT-11BT became two-phase mixture, and maximum piezoelectric coefficient was observed in BNT-7BT. It was shown that optimized electrical properties are related primarily to the capacity for domain texturing and not to phase coexistence

Phase II trial of preoperative radiochemotherapy with concurrent bevacizumab, capecitabine and oxaliplatin in patients with locally advanced rectal cancer

Background: Preoperative radiochemotherapy (RCT) with 5-FU or capecitabine is the standard of care for patients with locally advanced rectal cancer (LARC). Preoperative RCT achieves pathological complete response rates (pCR) of 10-15%. We conducted a single arm phase II study to investigate the feasibility and efficacy of addition of bevacizumab and oxaliplatin to preoperative standard RCT with capecitabine. Methods: Eligible patients had LARC (cT3-4; N0/1/2, M0/1) and were treated with preoperative RCT prior to planned surgery. Patients received conventionally fractionated radiotherapy (50.4 Gy in 1.8 Gy fractions) and simultaneous chemotherapy with capecitabine 825 mg/m2 bid (d1-14, d22-35) and oxaliplatin 50 mg/m2 (d1, d8, d22, d29). Bevacizumab 5 mg/kg was added on days 1, 15, and 29. The primary study objective was the pCR rate. Results: 70 patients with LARC (cT3-4; N0/1, M0/1), ECOG < 2, were enrolled at 6 sites from 07/2008 through 02/2010 (median age 61 years [range 39–89], 68% male). At initial diagnosis, 84% of patients had clinical stage T3, 62% of patients had nodal involvement and 83% of patients were M0. Mean tumor distance from anal verge was 5.92 cm (± 3.68). 58 patients received the complete RCT (full dose RT and full dose of all chemotherapy). During preoperative treatment, grade 3 or 4 toxicities were experienced by 6 and 2 patients, respectively: grade 4 diarrhea and nausea in one patient (1.4%), respectively, grade 3 diarrhea in 2 patients (3%), grade 3 obstipation, anal abscess, anaphylactic reaction, leucopenia and neutropenia in one patient (1.4%), respectively. In total, 30 patients (46%) developed postoperative complications of any grade including one gastrointestinal perforation in one patient (2%), wound-healing problems in 7 patients (11%) and bleedings in 2 patients (3%). pCR was observed in 12/69 (17.4%) patients. Pathological downstaging (ypT < cT and ypN ≤ cN) was achieved in 31 of 69 patients (44.9%). All of the 66 operated patients had a R0 resection. 47 patients (68.1%) underwent sphincter preserving surgery. Conclusions: The addition of bevacizumab and oxaliplatin to RCT with capecitabine was well tolerated and did not increase perioperative morbidity or mortality. However, the pCR rate was not improved in comparison to other trials that used capecitabine or capecitabine/oxaliplatin in preoperative radiochemotherapy

Der innovative Fehler im Kristall. Design keramischer Piezo- und Ferroelektrika durch Versetzungen

Versetzungen sind nicht nur für die plastische Verformung in Metallen zuständig. Sie können auch für das Einstellen hervorragender, temperaturstabiler Eigenschaftsprofile in Keramiken eingesetzt werden. Dies gilt besonders für Elektrokeramiken, deren elektrische sowie piezo- und ferroelektrische Eigenschaften technisch bedeutend sind. Das Verständnis des Einflusses von Versetzungen auf den elektrischen Ladungstransport wie auch auf das ferroelektrische Verhalten entwickelt sich rasant. Im wissenschaftlichen Fokus steht die Suche nach einem Ersatzmaterial für den Klassenprimus Bleizirkonattitanat (PZT), das ohne Blei auskommt und nachhaltig ist. Andere mögliche Anwendungen des Einprägens von Versetzungen werden derzeit für die Zukunft diskutiert

Clinically Approved Drugs Inhibit the Staphylococcus aureus Multidrug NorA Efflux Pump and Reduce Biofilm Formation

Staphylococcus aureus has acquired resistance to antibiotics since their first use. The S. aureus protein NorA, an efflux pump belonging to the major facilitator superfamily (MFS), contributes to resistance to fluoroquinolones (e.g., ciprofloxacin), biocides, dyes, quaternary ammonium compounds, and antiseptics. Different compounds have been identified as potential efflux pump inhibitors (EPIs) of NorA that result in increased intracellular concentration of antibiotics, restoring their antibacterial activity and cell susceptibility. However, none of the currently known EPIs have been approved for clinical use, probably due to their toxicity profiles. In the present study, we screened approved drugs for possible efflux pump inhibition. By screening a compound library of approximately 1200 different drugs, we identified nilotinib, a tyrosine kinase inhibitor, as showing the best efflux pump inhibitory activity, with a fractional inhibitory concentration index of 0.1875, indicating synergism with ciprofloxacin, and a minimum effective concentration as low as 0.195 μM. Moreover, at 0.39 μM, nilotinib, in combination with 8 μg/mL of ciprofloxacin, led to a significant reduction in biofilm formation and preformed mature biofilms. This is the first description of an approved drug that can be used as an efflux pump inhibitor and to reduce biofilms formation at clinically achievable concentrations

Diagnosis of malaria in a traveler 9 months after returning from West Africa by illumigene® LAMP assay: A case report

Loop-mediated isothermal amplification (LAMP) is a rapid molecular technique that has been introduced into malaria diagnosis. The test is easy to perform and offers high sensitivity. We report a 53-year-old male patient who was hospitalized with fever attacks, chills, and headache caused 9 months after returning from Africa. During his stay in Africa, he used malaria chemoprophylaxis. Microscopy of thin and thick blood films and rapid diagnostic antigen testing remained negative for three times. The EDTA blood samples were tested using the Meridian illumigene® malaria LAMP assay that gave a positive result for Plasmodium spp. Diagnosis of malaria was subsequently specified as P. ovale infection by real-time PCR. Ovale malaria often manifests with delay and low parasitemia. The patient was treated with atovaquone-proguanil, followed by primaquine for prophylaxis of relapse. This case illustrates the usefulness of the illumigene® malaria LAMP assay for initial screening of malaria parasites

Structural origins of relaxor behavior in a 0.96(Bi1/2Na1/2)TiO3-0.04BaTiO(3) single crystal under electric field

Diffuse x-ray scattering intensities from a single crystal of 0.96(Bi1/2Na1/2TiO3)-0.04(BaTiO3) have been collected at room temperature with and without application of an electric field along the [100] direction. Distinct features in the diffuse scattering intensities indicate correlations on a nanometer length scale. It is shown that locally correlated planar-like structures and octahedral tilt-domains within the room temperature rhombohedral R3c phase are both electrically active and are irreversibly affected by application of an electric field of 4.3 kV/mm. The field dependence of these nanoscale structures is correlated with the relaxor behavior of the material by macroscopic permittivity measurementsopen221

Onkolojide PET-BT ile multimodal görüntüleme

Pozitron-emisyon tomografi (PET) ile bilgisayarlı tomografinin (BT) birlikte kullanımı (PET-BT) PET'in klinik kullanımını önemli ölçüde artırmıştır. PET-BT, BT'nin yüksek çüzünürlüğünü PET'in yüksek duyarlığıyla birleştirmektedir. PET ve BT sonuçlarının tek incelemede ve aynı cihazla elde edilmesi nedeniyle her iki prosedürün en uygun birleşimi mümkündür. PET ve BT görüntülerinin klasik birleştirilmesine oranla, PET-BT ile PET'in doğruluğu yaklaşık %15 oranında artırılabilir. PET-BT'nin gücünden tam olarak yararlanmak sadece oral veya intravenöz kontrast ajanların kullanılmasıyla mümkündür. BT'nin X- ışını aynı zamanda atenüasyon düzeltmesi için kullanılır. Bu makalede ağırlıklı olarak akciğer kanseri, malign melanom, baş-boyun tümörleri, tiroid tümörleri ve kolorektal kanserler üzerinde durulmuş ve PET-BT'nin görsel gücü olgulara ait görüntüler aracılığıyla ortaya konmuştur.The combination of PET (positron emission tomography) with CT (computed tomography) has considerably enhanced the clinical application of PET. PET-CT combines the high resolution of CT with the high sensitivity of PET. As PET and CT results are obtained with one machine during one investigation, an optimal fusion of both procedures is possible. The accuracy of PET can be increased by about 15% by PET-CT, compared to conventional fusion of PET and CT images. The potential of PET-CT can only be fully used if contrast agents -either orally or intravenously- are applied. The Xrays of CT may also be used for attenuation correction. This article focuses mainly on PET-CT in lung cancer, malignant melanoma, head and neck tumors, thyroid tumors, and colorectal cancer, with illustrations of some cases documenting the potentials of PET-CT

Temperature dependence of piezoelectric properties of high- TC Bi (Mg1/2Ti1/2) O3 - PbTiO3

The temperature dependence of both polarization and electric-field induced strain was investigated for (1-x)Bi(Mg1/2Ti1/2)O-3-xPbTiO(3) (x=0.36, 0.37, and 0.38), with the morphotropic phase boundary located at x=0.37. Remanent polarization (P-r) and maximum polarization (P-max) of all compositions are enhanced with increasing temperature up to 175 degrees C, which is rationalized as improved domain switching due to reduced tetragonality (c/a). The hysteresis during unipolar electric cycling tends to decrease with increase in the fraction of tetragonal phase. Temperature dependent x-ray diffraction demonstrates that switched non-180 degrees domains are stable against thermal depoling above 200 degrees C, which indicates that the currently investigated materials are suitable for high temperature applications. This promising high-T-C piezoelectric is further discussed with reference to oxygen octahedron of the tilted R3c and untilted R3m space groups and the tolerance factor (t).open371

Dislocation and grain boundary interaction in oxides: Slip transmission or cracking?

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Thermally enhanced dislocation density improves both hardness and fracture toughness in single‐crystal SrTiO₃

Dislocation‐tuned functionality in ceramic oxides for potential versatile applications gains increasing attention. As the widespread chemical doping suffers from poor temperature stability, dislocations in well‐controlled mesoscopic structure may be an alternative to thermally stable intrinsic doping features. To this end, the dislocation density in plastic zones introduced by cyclic Brinell indentation is considered under thermal annealing conditions. The considerably enhanced dislocation density due to thermal treatment is found to impact both microhardness and fracture toughness, albeit only to a modest degree. The mechanistic understanding centers around enhanced mobility and multiplication of the pre‐engineered dislocations at elevated temperatures driven by the residual indentation stress, as well as the strengthened interaction of point defects and dislocations at high temperature