215 research outputs found

    Slow magnetic dynamics and hysteresis loops of a bulk ferromagnet

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    Magnetic dynamics of a bulk ferromagnet, a new single crystalline compound Co7(TeO3)4Br6, was studied by ac susceptibility and the related techniques. Very large Arrhenius activation energy of 17.2 meV (201 K) and long attempt time (2x10^(-4)s) span the full spectrum of magnetic dynamics inside a convenient frequency window, offering a rare opportunity for general studies of magnetic dynamics. Within the experimental window the ac susceptibility data build almost ideally semicircular Cole-Cole plots. Comprehensive study of experimental dynamic hysteresis loops of the compound is presented and interpreted within a simple thermal-activation-assisted spin lattice relaxation model for spin reversal. Quantitative agreement between the experimental results and the model's prediction for dynamic coercive field is achieved by assuming the central physical quantity, the Debye relaxation rate, to depend on frequency, as well as on the applied field strength and sample temperature. Cross-over between minor- to major hysteresis loops is carefully analyzed. Low-frequency limitations of the model, relying on domain wall pinning effects, are experimentally detected and appropriately discussed.Comment: A paragraph on dynamical-hysteresis assymetry added, text partially revised; Accepted in Physical Review

    Culture as the main factor of social determinant of consumers behavior

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    The social (sociological) factors are very important in the formation of long-term habits of consumer behavior. To explain the need for a certain product or service, it is necessary to understand the social determinants of demand. The influence of social (sociological) factors on the behavior of consumers had developed and changed in accordance with the social and economic development of population. It directly influenced the increase or decrease of the standard of living,because with socialization, human as consumer accepts values,beliefs, and customs and so on, acquired by education and upbringing, and changing some habits that are not socially acceptable. The fact is that human cannot be extracted from the environment in which it lives, because every individual has the same biological needs, but depending on where one lives, to which civilization, culture or subculture belongs to, there are more or less differences in behavior. The process by The social profile of consumers is determined by the influence of external factors, because it lives in a complex environment that affects its behavior. Social environment has a primary influence on forming personality of the individual, and thus the behavior is the result of such influence

    Biocompatible microemulsions for improved dermal delivery of sertaconazole nitrate: Phase behavior study and microstructure influence on drug biopharamaceutical properties

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    The aim of this study was development of biocompatible topical microemulsions (MEs) for incorporation and improved dermal delivery of sertaconazole nitrate (SN). For this purpose, phase behavior and microstructure of pseudo-ternary glycereth-7-caprylate/caprate (Emanon EV-E, EV)/cosurfactant/Capryol (TM) 90/water systems were investigated. Furhermore, the influence of these properties on the drug skin delivery was also assessed. Expansion of ME single-phase regions with the use of short chain alcohols was a consequence of the more fluid interface when compared to other investigated systems, which was confirmed by electron paramagnetic resonance spectroscopy-EPR. The chosen bicontinuous to inverted bicontinuous formulations were assessed against the ME based on polysorbate 80 as referent sample. Despite incorporation of SN within the selected formulations induced similar alternations in electrical conductivity, viscosity and pH values, obtained EPR spectra suggested different SN localization: within the oil phase (for most of the EV based formulations), or interacting with the interface (polysorbate 80 based formulation). Due to higher in vitro drug release (12.24%-18.53%), ex vivo SN penetration into porcine ear skin (dermal retention Enhancement Ratio (ERO) ranged from 2.66 to 4.25) and pronounced antifungal activity, the chosen MEs represent promising vehicles for dermal delivery of SN in treatment of cutaneous fungal infections. The biopharmaceutical and skin performance differences obtained with different formulations were possible to be explained on the basis of their physicochemical characteristics.This is the peer-reviewed version of the article: Pajic, N. B., Nikolić, I., Mitsou, E., Papadimitriou, V., Xenakis, A., Randjelović, D., Dobricic, V., Smitran, A., Cekic, N., Calija, B.,& Savić, S. D. (2018). Biocompatible microemulsions for improved dermal delivery of sertaconazole nitrate: Phase behavior study and microstructure influence on drug biopharamaceutical properties. Journal of Molecular LiquidsElsevier Science Bv, Amsterdam., 272, 746-758. [https://doi.org/10.1016/j.molliq.2018.10.002]The published version: [https://cer.ihtm.bg.ac.rs/handle/123456789/2360

    Clinical and molecular characterization of HER2 amplified-pancreatic cancer

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    <p>Background: Pancreatic cancer is one of the most lethal and molecularly diverse malignancies. Repurposing of therapeutics that target specific molecular mechanisms in different disease types offers potential for rapid improvements in outcome. Although HER2 amplification occurs in pancreatic cancer, it is inadequately characterized to exploit the potential of anti-HER2 therapies.</p> <p>Methods: HER2 amplification was detected and further analyzed using multiple genomic sequencing approaches. Standardized reference laboratory assays defined HER2 amplification in a large cohort of patients (n = 469) with pancreatic ductal adenocarcinoma (PDAC).</p> <p>Results: An amplified inversion event (1 MB) was identified at the HER2 locus in a patient with PDAC. Using standardized laboratory assays, we established diagnostic criteria for HER2 amplification in PDAC, and observed a prevalence of 2%. Clinically, HER2- amplified PDAC was characterized by a lack of liver metastases, and a preponderance of lung and brain metastases. Excluding breast and gastric cancer, the incidence of HER2-amplified cancers in the USA is >22,000 per annum.</p> <p>Conclusions: HER2 amplification occurs in 2% of PDAC, and has distinct features with implications for clinical practice. The molecular heterogeneity of PDAC implies that even an incidence of 2% represents an attractive target for anti-HER2 therapies, as options for PDAC are limited. Recruiting patients based on HER2 amplification, rather than organ of origin, could make trials of anti-HER2 therapies feasible in less common cancer types.</p&gt

    Wearable resistance sprint running is superior to training with no load for retaining performance in pre-season training for rugby athletes

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    This study determined the effects of a six-week lower-limb wearable resistance training (WRT) intervention on sprint running time, velocity, and horizontal force-velocity mechanical variables. Twenty-two collegiate/semi-professional rugby athletes completed pre- and post-intervention testing of three maximal effort 30 m sprints. A radar device was used to measure sprint running velocity from which horizontal force-velocity mechanical profiling variables were calculated. All athletes completed two dedicated sprint training sessions a week for six-weeks during pre-season. The intervention (wearable resistance, WR) group completed the sessions with 1% body mass load attached to the left and right shanks (i.e. 0.50% body mass load on each limb), whilst the control group completed the same sessions unloaded. For the control group, all variables were found to detrain significantly (p ≤ 0.05) over the training period with large detraining effects (ES > 0.80) for theoretical maximal horizontal force, slope of the force-velocity profile, maximal ratio of force, index of force application, 5 m and 10 m times. For the WR group, there were no significant changes to any recorded variables (all p > 0.05) and all effects of training were trivial or small (ES 0.80) except theoretical maximal velocity, 30 m time, and maximal velocity. The addition of light wearable resistance to sprint training during a six-week pre-season block enables the maintenance of sprint performance and mechanical output qualities that otherwise would detrain due to inadequate training frequencies

    Pharmacokinetic and clinical profile of a novel formulation of bosentan in children with pulmonary arterial hypertension: the FUTURE-1 study

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    center dot Exposure to bosentan was lower in paediatric pulmonary arterial hypertension (PAH) patients treated with the marketed adult formulation at a dose of about 2 mg kg-1 when compared with adult PAH patients. center dot In healthy adult subjects, bosentan pharmacokinetics are less than dose-proportional at doses of >= 500 mg. WHAT THIS STUDY ADDS center dot The pharmacokinetics of a new paediatric bosentan formulation were characterized in paediatric PAH patients. center dot The level of exposure to bosentan as observed in adult PAH patients cannot be reached in paediatric patients with b.i.d. dosing. center dot In paediatric PAH patients, nondose-proportional pharmacokinetics of bosentan occur at lower doses when compared with healthy adult subjects. AIM To show equivalent bosentan exposure in paediatric patients with pulmonary arterial hypertension (PAH) when compared with a cohort of historical controls of adult PAH patients using a newly developed paediatric formulation. METHODS Thirty-six paediatric PAH patients were enrolled in this multicentre, prospective, open-label, noncontrolled study and treated for 4 weeks with bosentan 2 mg kg-1 b.i.d. and then for 8 weeks with 4 mg kg-1 b.i.d. Blood samples were taken for pharmacokinetic purposes. Exploratory efficacy measurements included World Health Organization (WHO) functional class and parent's and clinician's Global Clinical Impression scales. RESULTS Comparing children with a historical group of adults, the geometric mean ratio (90% confidence interval) of the area under the plasma concentration-time curve was 0.54 (0.37, 0.78), i.e. children had lower exposure to bosentan than adults. Bosentan concentrations following doses of 2 and 4 mg kg-1 were similar. Improvements in WHO functional class and the Global Clinical Impression scales occurred mainly in bosentan-naive patients, whereas the rare worsenings occurred in patients already on bosentan prior to study initiation. The paediatric formulation was well accepted and bosentan well tolerated in this study. No cases of elevated liver enzymes or anaemia were reported. CONCLUSIONS Exposure to bosentan, as shown comparing the results from this study with those from a study in adults, was different in paediatric and adult PAH patients. Since FUTURE-1 and past studies suggest a favourable benefit-risk profile for bosentan at 2 mg kg-1 b.i.d., this dose is recommended for children with PAH. The new paediatric formulation was well tolerate

    SerpinB2 regulates stromal remodelling and local invasion in pancreatic cancer

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    Pancreatic cancer has a devastating prognosis, with an overall 5-year survival rate of ~8%, restricted treatment options and characteristic molecular heterogeneity. SerpinB2 expression, particularly in the stromal compartment, is associated with reduced metastasis and prolonged survival in pancreatic ductal adenocarcinoma (PDAC) and our genomic analysis revealed that SERPINB2 is frequently deleted in PDAC. We show that SerpinB2 is required by stromal cells for normal collagen remodelling in vitro, regulating fibroblast interaction and engagement with collagen in the contracting matrix. In a pancreatic cancer allograft model, co-injection of PDAC cancer cells and SerpinB2(-/-) mouse embryonic fibroblasts (MEFs) resulted in increased tumour growth, aberrant remodelling of the extracellular matrix (ECM) and increased local invasion from the primary tumour. These tumours also displayed elevated proteolytic activity of the primary biochemical target of SerpinB2-urokinase plasminogen activator (uPA). In a large cohort of patients with resected PDAC, we show that increasing uPA mRNA expression was significantly associated with poorer survival following pancreatectomy. This study establishes a novel role for SerpinB2 in the stromal compartment in PDAC invasion through regulation of stromal remodelling and highlights the SerpinB2/uPA axis for further investigation as a potential therapeutic target in pancreatic cancer

    MCL-1 antagonism enhances the anti-invasive effects of dasatinib in pancreatic adenocarcinoma.

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    Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest malignancies. It is phenotypically heterogeneous with a highly unstable genome and provides few common therapeutic targets. We found that MCL1, Cofilin1 (CFL1) and SRC mRNA were highly expressed by a wide range of these cancers, suggesting that a strategy of dual MCL-1 and SRC inhibition might be efficacious for many patients. Immunohistochemistry revealed that MCL-1 protein was present at high levels in 94.7% of patients in a cohort of PDACs from Australian Pancreatic Genome Initiative (APGI). High MCL1 and Cofilin1 mRNA expression was also strongly predictive of poor outcome in the TCGA dataset and in the APGI cohort. In culture, MCL-1 antagonism reduced the level of the cytoskeletal remodeling protein Cofilin1 and phosphorylated SRC on the active Y416 residue, suggestive of reduced invasive capacity. The MCL-1 antagonist S63845 synergized with the SRC kinase inhibitor dasatinib to reduce cell viability and invasiveness through 3D-organotypic matrices. In preclinical murine models, this combination reduced primary tumor growth and liver metastasis of pancreatic cancer xenografts. These data suggest that MCL-1 antagonism, while reducing cell viability, may have an additional benefit in increasing the antimetastatic efficacy of dasatinib for the treatment of PDAC

    Lost in translation: Returning germline genetic results in genome-scale cancer research

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    Background: The return of research results (RoR) remains a complex and well-debated issue. Despite the debate, actual data related to the experience of giving individual results back, and the impact these results may have on clinical care and health outcomes, is sorely lacking. Through the work of the Australian Pancreatic Cancer Genome Initiative (APGI) we: (1) delineate the pathway back to the patient where actionable research data were identified; and (2) report the clinical utilisation of individual results returned. Using this experience, we discuss barriers and opportunities associated with a comprehensive process of RoR in large-scale genomic research that may be useful for others developing their own policies. Methods: We performed whole-genome (n = 184) and exome (n = 208) sequencing of matched tumour-normal DNA pairs from 392 patients with sporadic pancreatic cancer (PC) as part of the APGI. We identified pathogenic germline mutations in candidate genes (n = 130) with established predisposition to PC or medium-high penetrance genes with well-defined cancer associated syndromes or phenotypes. Variants from candidate genes were annotated and classified according to international guidelines. Variants were considered actionable if clinical utility was established, with regard to prevention, diagnosis, prognostication and/or therapy. Results: A total of 48,904 germline variants were identified, with 2356 unique variants undergoing annotation and in silico classification. Twenty cases were deemed actionable and were returned via previously described RoR framework, representing an actionable finding rate of 5.1%. Overall, 1.78% of our cohort experienced clinical benefit from RoR. Conclusion: Returning research results within the context of large-scale genomics research is a labour-intensive, highly variable, complex operation. Results that warrant action are not infrequent, but the prevalence of those who experience a clinical difference as a result of returning individual results is currently low
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