182 research outputs found
Microstructure and Dielectric Properties of Barium-vanadate Glasses
AbstractThe ac and dc conductivity in barium-vanadate glasses was investigated as a function of temperature and frequency with the use of impedance spectroscopy. The topography and microstructure of glasses were investigated by the means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. The XRD results show that all samples are amorphous but microscopy investigation reveals that glasses with greater amount of V2O5 contain nanostructures. The influence of V2O5 quantity on dielectric properties was checked. The activation energy of dc conduction process was evaluated. On the basis of Jonscher universal dielectric response the temperature dependence of conductivity parameters were determined and compared to theoretical models collected by Elliott
An immunohistochemical study of the thyroid parafollicular (C) cells in rats treated with cannabinoids - preliminary investigations
The purpose of the present study was to evaluate the effect of a single intraperitoneal
injection of a stable analogue of endogenous cannabinoid anandamide
- R-(+)-methanandamide (2.5 mg/kg) and CP 55,940 (0.25 mg/kg), an
egzogenous CB1 receptor-agonist, on the calcitonin (CT) immunoreactivity of
the thyroid parafollicular (C) cells. Four hours after injection with both cannabinoids
CT immunoreactivity, evaluated with an avidin-biotin peroxidase complex
method by means of rabbit antibodies against CT, was seen to be enhanced
in the parafollicular cells in comparison to those of the control group.
In thyroids taken from cannabinoid-treated rats the majority of follicles, particularly
those located peripherally were large in size, and had low epithelium.
Moreover, dilatation of the blood vessels was observed. These changes were
accompanied by a significant decrease in CT plasma level, without changes in
calcium concentrations. This is the first evidence that a single injection of the
cannabinoids R-(+)-methanandamide and CP 55,940 significantly decreases
the activity of thyroid C cells
Correlation of diaphragm surgical findings with preoperative CT scans in ovarian cancer
Correlation of diaphragm surgical findings in ovarian cancer patients with and without diaphragm metastases with pre-operative CT diaphragm findings to assess sensitivity and specificity for diaphragm disease. Material and Methods: A retrospective study of 120 ovarian cancer patients (60 with and 60 without diaphragm metastases at surgery), FIGO Stage IIIC or IV, undergoing cytoreductive surgery at Mayo Clinic, Arizona, between January 2000 and October 2014. All patients had preoperative imaging with CT scan of abdomen and pelvis including the lower lung fields. CTs were not reviewed retrospectively. Results: Among 60 patients with diaphragm metastases, preoperative CTs were positive for diaphragm disease in 17 patients, with a sensitivity rate of 28% (CI 95%: 0.17-0.41). All 60 patients with no diaphragm metastases had negative CTs, with a specificity of 100% (CI 95%: 94.0%-100%). When analyzed by lesion size, CTs were negative in 66.7-80% of patients with diaphragm lesions ranging from 1-15 mm. There was a trend towards increased detection rate with increasing size of lesions, but it did not reach significance (p = 0.529). CT detection rate for single metastatic lesion was 18.2% (6/33) and for multiple lesions it was 25.9% (7/27). There was no difference for CT identification of right, left, or bilateral metastases (p = 0.399). The sensitivity and specificity of CT for pleural effusion was 100% (CI 95%: 72.2%-100%) and 88% (CI 95%: 76.2%- 94.4%), respectively. The area under the receiver operating characteristic (ROC) curve was 0.680 (CI 95%: 55.3%-72.2%) for CT detection of diaphragm metastases and 0.957 (CI 95%: 79.9%-95.3%) for pleural effusions. Conclusion: CT has a low sensitivity and a high specificity for the prediction of diaphragm metastases in ovarian cancer. The size, location, and number of diaphragm lesions do not significantly improve CT detection rat
Selektivno određivanje Fe(III) u uzorcima Fe(II) UV-spektrofotometrijom pomoću kvercetina i morina
Selective UV-spectrophotometric methods for determination of iron(III) in iron(II) samples have been developed. The methods are based on the interaction of Fe(III) with quercetin and morin, compounds of the flavonoid group. Redox reactions occurring between Fe(III) ions and the reagents used make the basis for the detection. Iron(II) does not react with quercetin and morin under the conditions applied [aqueous-methanolic (3 : 2) solutions, 0.3 mol L1 HCl, and 1.2 × 10-4 mol L1 quercetin (morin)] and does not interfere with the determination of Fe(III). Iron(III) can be determined up to 15 μg mL1 using both the examined systems. The detection limits are 0.06 and 0.38 μg mL1 when using quercetin or morin, respectively. The method with quercetin was applied to the determination of Fe(III) (ca. 0.2%) in a Fe(II) pharmaceutical product.U radu je opisan razvoj selektivnih UV-spektrofotometrijskih metoda za određivanje željeza(III) u uzorku željeza(II). Metode se temelje na redoks reakciji Fe(III) sa spojevima iz skupine flavonoida kvercetinom i morinom u reakcijskim uvjetima u kojima željezo(II) ne reagira (vodeno/metanolna otopina 3:2, 0,3 mol L1 HCl, 1,2 x 104 mol L1 kvercetin ili morin). Najniža koncentracija željeza(III) koja se može odrediti je 15 μg mL1 u oba ispitivana sustava. Granice detekcije su 0,06 i 0,38 μg mL1 ako se koristi kvercetin, odnosno morfin. Metoda s kvercetinom primijenjena je za određivanje Fe(III (približno 0,2%) u farmaceutskom produktu Fe(II)
Pegylated interferon alfa-2a for polycythemia vera or essential thrombocythemia resistant or intolerant to hydroxyurea
Prior studies have reported high response rates with recombinant interferon-a (rIFN-a) therapy in patients with essential thrombocythemia (ET) and polycythemia vera (PV). To further define the role of rIFN-a,we investigated the outcomes of pegylated-rIFN-a2a (PEG) therapy in ET and PV patients previously treated with hydroxyurea (HU). The Myeloproliferative Disorders Research Consortium (MPD-RC)-111 study was an investigator-initiated, international, multicenter, phase 2 trial evaluating the ability of PEG therapy to induce complete (CR) and partial (PR) hematologic responses in patients with high-risk ET or PVwho were either refractory or intolerant to HU. The study included 65 patients with ET and 50 patients with PV. The overall response rates (ORRs; CR/PR) at 12 monthswere 69.2%(43.1% and 26.2%) in ET patients and 60% (22% and 38%) in PV patients. CR rates were higher in CALR-mutated ET patients (56.5% vs 28.0%; P 5 .01), compared with those in subjects lacking a CALR mutation. The median absolute reduction in JAK2V617F variant allele fraction was 26% (range, 284%to 47%) in patients achieving a CR vs 14%(range, 218% to 56%) in patients with PR or nonresponse (NR). Therapy was associated with a significant rate of adverse events (AEs); most were manageable, and PEG discontinuation related to AEs occurred in only 13.9% of subjects. We conclude that PEG is an effective therapy for patients with ET or PV who were previously refractory and/or intolerant of HU
Synergistic combination of cytotoxic chemotherapy and cyclin-dependent kinase 4/6 inhibitors in biliary tract cancers
Background and aims: Biliary tract cancers (BTCs) are uncommon, but highly lethal, gastrointestinal malignancies. Gemcitabine/cisplatin is a standard-of-care systemic therapy, but has a modest impact on survival and harbors toxicities, including myelosuppression, nephropathy, neuropathy, and ototoxicity. Whereas BTCs are characterized by aberrations activating the cyclinD1/cyclin-dependent kinase (CDK)4/6/CDK inhibitor 2a/retinoblastoma pathway, clinical use of CDK4/6 inhibitors as monotherapy is limited by lack of validated biomarkers, diffident preclinical efficacy, and development of acquired drug resistance. Emerging studies have explored therapeutic strategies to enhance the antitumor efficacy of CDK4/6 inhibitors by the combination with chemotherapy regimens, but their mechanism of action remains elusive.Approach and results: Here, we report in vitro and in vivo synergy in BTC models, showing enhanced efficacy, reduced toxicity, and better survival with a combination comprising gemcitabine/cisplatin and CDK4/6 inhibitors. Furthermore, we demonstrated that abemaciclib monotherapy had only modest efficacy attributable to autophagy-induced resistance. Notably, triplet therapy was able to potentiate efficacy through elimination of the autophagic flux. Correspondingly, abemaciclib potentiated ribonucleotide reductase catalytic subunit M1 reduction, resulting in sensitization to gemcitabine.Conclusions: As such, these data provide robust preclinical mechanistic evidence of synergy between gemcitabine/cisplatin and CDK4/6 inhibitors and delineate a path forward for translation of these findings to preliminary clinical studies in advanced BTC patients.</p
Problems, history and directions of development of Fire Research Department
Działalność Zakładu Badań Ogniowych obejmuje problematykę bezpieczeństwa pożarowego budynków z uwzględnieniem nośności konstrukcji, reakcji na ogień materiałów budowlanych, ewakuacji i rozwoju pożaru oraz rozprzestrzeniania produktów pożaru w budynku. Fundamentem pracy Zakładu jest baza laboratoryjna. Zakład powstał w 1974 roku, lecz podstawy działalności badawczej uzyskał dopiero w połowie lat osiemdziesiątych. W ostatnich latach w Zakładzie są rozwijane kierunki zmierzające do kompleksowej oceny bezpieczeństwa pożarowego przy zastosowaniu symulacji komputerowych. Ważnym obszarem działalności Zakładu jest współpraca z ISO, CEN, EGOLF i wprowadzanie nowych metod, norm CEN oraz klasyfikacji.Activity of Fire Research Department includes the problems of fire safety of buildings, with taking into consideration the construction stability, reaction to fire of building materials, evacuation and fire development, as well as spreading of fire products inside the building. The foundation of Department's work is its laboratory basis. Department came into existance in 1974, but the bases of its research activity it obtained not earlier than in the middle of eighties. In recent years, the directions aiming at complex assessment of fire safety on the base of computer simulations are developed. The important area of activity is international cooperation with ISO, CEN, EGOLF and introducing of new methods, CEN standards and classification
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