68 research outputs found

    Biomimetic self-assembling copolymer-hydroxyapatite nanocomposites with the nanocrystal size controlled by citrate

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    Citrate binds strongly to the surface of calcium phosphate (apatite) nanocrystals in bone and is thought to prevent crystal thickening. In this work, citrate added as a regulatory element enabled molecular control of the size and stability of hydroxyapatite (HAp) nanocrystals in synthetic nanocomposites, fabricated with self-assembling block copolymer templates. The decrease of the HAp crystal size within the polymer matrix with increasing citrate concentration was documented by solid-state nuclear magnetic resonance (NMR) techniques and wide-angle X-ray diffraction (XRD), while the shapes of HAp nanocrystals were determined by transmission electron microscopy (TEM). Advanced NMR techniques were used to characterize the interfacial species and reveal enhanced interactions between mineral and organic matrix, concomitant with the size effects. The surface-to-volume ratios determined by NMR spectroscopy and long-range 31P{1H} dipolar dephasing show that 2, 10, and 40 mM citrate changes the thicknesses of the HAp crystals from 4 nm without citrate to 2.9, 2.8, and 2.3 nm, respectively. With citrate concentrations comparable to those in body fluids, HAp nanocrystals of sizes and morphologies similar to those in avian and bovine bones have been produced

    Evidence from the Gediz graben for episodic two-stage extension in western Turkey

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    Western Turkey falls within a wide belt of NNE-SSW-directed, active continental extension, generally similar to the Basin and Range Province of the USA It comprises a zone of WNW-ESE-trending major grabens. Derailed study of the Gediz graben reveals two contrasting infills that represent two distinct extensional stages, separated by a short phase of compression. The older infill consists of an 800m thick, folded and exhumed continental sedimentary sequence with intercalated calc-alkaline volcanics. It accumulated in a basin formed in the northern hanging wail of a detachment fault during Miocene-early Pliocene times. The younger infill rests on the older infill with angular unconformity and consists of about 170 m of undeformed, terraced continental sediments and basaltic lavas. It accumulated during Plio-Quaternary times in an asymmetric graben bounded by step-like normal faults. This later extension was probably triggered by the commencement of sea-Boor spreading along the Red Sea in early Pliocene times and has persisted to the present. Almost all the grabens in western Turkey are best explained by this episodic, two-stage graben model with an intervening phase of short-term compression, which differs from the progressive evolution inferred for the Basin and Range Province of the USA

    Prognostic value of pre-and posttreatment PET/CT parameters in patients diagnosed with advanced stage NSCLC

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    Background: PET imaging involves several parameters. However, it is not well known which parameters in each measurable site of tumors may have a greater effect on oncologic outcomes. Method: This study included a total of 42 patients diagnosed with histology-proven NSCLC. Baseline and consecutive FDG-PET scans were carried out 3 weeks before and at least 3 months after treatment, respectively. Results: According to the PERCIST, 9 (21%) patients had Complete Response (CR), and 3 of them underwent surgical resection. Sixteen patients (38%) had Partial Response (PR), and 4 (9.5%) had Stable Disease (SD), the remaining 15 (35%) had Progressive Disease (PD). Patients who responded to the treatment had significantly higher Overall Survival (OS) and Progression Free Survival (PFS), 15 versus 9.5 months and 10 versus 6 months, respectively. The SUVmax values decreased from 12.2 to 3.7 (P=<0.001), and the mediastinal lymph nodes SUVmax decreased from 6 to 0 (P=<0.001) in the responder group. The median TLG of the primary lesion showed a statistically significant decrease from 279 to 13.6 (P=0.0001), the median TLG of the mediastinal lymph nodes decreased from 13.2 to 0 (P= 0.04), and the median Whole Body (WB) TLG decreased from 338 to 17 (P=0.002) in the responder group. The posttreatment WB TLG was significantly correlated with OS and PFS. Conclusion: This study showed that the posttreatment WB TLG is significantly associated with oncologic outcomes. The metabolic changes in the mediastinal lymph nodes, as shown by the SUVmax and TLG, have a prognostic value in patients who develop new metastases during treatment. Further study in a homogenous NSCLC population can help increase our understanding of the prognostic value of PET/CT parameters. © 2018 Bentham Science Publishers

    Chemical Composition and Repellent Activity of the Essential Oil of Ocimum minimum L. on Drosophila Species

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    The chemical composition of the essential oil of Ocimum minimum L. from Istanbul, Turkey was investigated and repellent activity against Drosophila species were examined. Ocimum minimum L. grown in Istanbul with its high content of linalool (36-41 %) showed a good repellency
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