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Search Results: 1 - 10 of 406048 matches for " Daniel I H?d?rug? "
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Titanocene / cyclodextrin supramolecular systems: a theoretical approach
Adrian Rivi?, Nicoleta G Hdrug, Zeno Garban, Daniel I Hdrug
Chemistry Central Journal , 2012, DOI: 10.1186/1752-153x-6-129
Abstract: This study presents a theoretical approach on the nanoencapsulation of a series of titanocenes with cytotoxic activity in α-, β-, and γ-cyclodextrin. The HyperChem 5.11 package was used for building and molecular modelling of titanocene and cyclodextrin structures, as well as for titanocene/cyclodextrin complex optimization. For titanocene/cyclodextrin complex optimization experiments, the titanocene and cyclodextrin structures in minimal energy conformations were set up at various distances and positions between molecules (molecular mechanics functionality, MM+). The best interaction between titanocene structures and cyclodextrins was obtained in the case of β- and γ-cyclodextrin, having the hydrophobic moieties oriented to the secondary face of cyclodextrin. The hydrophobicity of titanocenes (logP) correlate with the titanocene-cyclodextrin interaction parameters, especially with the titanocene-cyclodextrin interaction energy; the compatible geometry and the interaction energy denote that the titanocene/β- and γ-cyclodextrin complex can be achieved. Valuable quantitative structure-activity relationships (QSARs) were also obtained in the titanocene class by using the same logP as the main parameter for the in vitro cytotoxic activity against HeLa, K562, and Fem-x cell lines.According to our theoretical study, the titanocene/cyclodextrin inclusion compounds can be obtained (high interaction energy; the encapsulation is energetically favourable). Further, the most hydrophobic compounds are better encapsulated in β- and γ-cyclodextrin molecules and are more stable (from energetically point of view) in comparison with α-cyclodextrin case. This study suggests that the titanocene / β- and γ-cyclodextrin complexes (or synthetically modified cyclodextrins with higher water solubility) could be experimentally synthesized and could have enhanced cytotoxic activity and even lower toxicity.Cancer is a generic name comprises a great number of medical affections, having various
Ficaria verna Huds. extracts and their β-cyclodextrin supramolecular systems
Nicoleta G Hdrug
Chemistry Central Journal , 2012, DOI: 10.1186/1752-153x-6-16
Abstract: F. verna flowers and leaves extracts were obtained by semi-continuous solid-liquid extraction. The raw concentrated extract was spectrophotometrically analyzed in order to quantify the flavonoids from plant parts and to evaluate the antioxidant activity of these extracts. The F. verna extracts were used for obtaining β-cyclodextrin complexes; these were analyzed by scanning electron microscopy and Karl Fischer water titration; spectrophotometry was used in order to quantifying the flavonoids and evaluates the antioxidant activity. A higher concentration of flavonoids of 0.5% was determined in complexes obtained by crystallisation method, while only a half of this value was calculated for kneading method. The antioxidant activity of these complexes was correlated with the flavonoid content and this parameter reveals possible controlled release properties.The flavonoid content of F. verna Huds. from the West side of Romania (Banat county) is approximately the same in flowers and leaves, being situated at a medium value among other studies. β-Cyclodextrin complexes of F. verna extracts are obtained with lower yields by crystallisation than kneading methods, but the flavonoids (as quercetin) are better encapsulated in the first case most probably due to the possibility to attain the host-guest equilibrium in the slower crystallisation process. F. verna extracts and their β-cyclodextrin complexes have antioxidant activity even at very low concentrations and could be used in proper and valuable pharmaceutical formulations with enhanced bioactivity.Ficaria verna Huds. (lesser celandine, fig buttercup) is a widespread perennial plant which is found throughout Europe, West Asia, and North America, being sometimes called "the spring messenger" due to the blossoming period starting from March. It is also called "an invasive" plant in North America due to the use of these species for specific restoration-preservation processes in native habitats [1-3]. The name is derived from
Tuning the spin Hamiltonian of NENP by external pressure: a neutron scattering study
I. A. Zaliznyak,D. C. Dender,C. Broholm,Daniel H. Reich
Physics , 1997, DOI: 10.1103/PhysRevB.57.5200
Abstract: We report an inelastic neutron scattering study of antiferromagnetic spin dynamics in the Haldane chain compound Ni(C2H8N2)2NO2ClO4 (NENP) under external hydrostatic pressure P = 2.5 GPa. At ambient pressure, the magnetic excitations in NENP are dominated by a long-lived triplet mode with a gap which is split by orthorhombic crystalline anisotropy into a lower doublet centered at $\Delta_\perp\approx$ 1.2meV and a singlet at $\Delta_\parallel\approx$ 2.5meV. With pressure we observe appreciable shifts in these levels, which move to $\Delta_\perp{(2.5GPa)}\approx$ 1.45 meV and $\Delta_\parallel(2.5GPa)\approx$ 2.2meV. The dispersion of these modes in the crystalline c-direction perpendicular to the chain was measured here for the first time, and can be accounted for by an interchain exchange J'_c approximately 3e-4*J which changes only slightly with pressure. Since the average gap value $\Delta_H\approx$ 1.64 meV remains almost unchanged with P, we conclude that in NENP the application of external pressure does not affect the intrachain coupling J appreciably, but does produce a significant decrease of the single-ion anisotropy constant from D/J = 0.16(2) at ambient pressure to D/J = 0.09(7) at P = 2.5 GPa.
Parameter and State Estimation of Experimental Chaotic Systems Using Synchronization
Jack C. Quinn,Paul H. Bryant,Daniel R. Creveling,Sallee R. Klein,Henry D. I. Abarbanel
Physics , 2009,
Abstract: We examine the use of synchronization as a mechanism for extracting parameter and state information from experimental systems. We focus on important aspects of this problem that have received little attention previously, and we explore them using experiments and simulations with the chaotic Colpitts oscillator as an example system. We explore the impact of model imperfection on the ability to extract valid information from an experimental system. We compare two optimization methods: an initial value method and a constrained method. Each of these involve coupling the model equations to the experimental data in order to regularize the chaotic motions on the synchronization manifold. We explore both time dependent and time independent coupling. We also examine both optimized and fixed (or manually adjusted) coupling. For the case of an optimized time dependent coupling function u(t) we find a robust structure which includes sharp peaks and intervals where it is zero. This structure shows a strong correlation with the location in phase space and appears to depend on noise, imperfections of the model, and the Lyapunov direction vectors. Comparison of this result with that obtained using simulated data may provide one measure of model imperfection. The constrained method with time dependent coupling appears to have benefits in synchronizing long datasets with minimal impact, while the initial value method with time independent coupling tends to be substantially faster, more flexible and easier to use. We also describe a new method of coupling which is useful for sparse experimental data sets. Our use of the Colpitts oscillator allows us to explore in detail the case of a system with one positive Lyapunov exponent. The methods we explored are easily extended to driven systems such as neurons with time dependent injected current.
Identification of Differentially Expressed Proteins in Murine Embryonic and Postnatal Cortical Neural Progenitors
Lorelei D. Shoemaker,Nicholas M. Orozco,Daniel H. Geschwind,Julian P. Whitelegge,Kym F. Faull,Harley I. Kornblum
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0009121
Abstract: The central nervous system (CNS) develops from a heterogeneous pool of neural stem and progenitor cells (NSPC), the underlying differences among which are poorly understood. The study of NSPC would be greatly facilitated by the identification of additional proteins that mediate their function and that would distinguish amongst different progenitor populations.
Stone Formation from Nonabsorbable Clip Migration into the Collecting System after Robot-Assisted Partial Nephrectomy
Ziho Lee,Christopher E. Reilly,Blake W. Moore,Jack H. Mydlo,David I. Lee,Daniel D. Eun
Case Reports in Urology , 2014, DOI: 10.1155/2014/397427
Abstract: We describe a case in which a Weck Hem-o-lok clip (Teleflex, Research Triangle Park, USA) migrated into the collecting system and acted as a nidus for stone formation in a patient after robot-assisted partial nephrectomy. The patient presented 2 years postoperatively with left-sided renal colic. Abdominal computed tomography scan showed a 10 millimeter renal calculus in the left middle pole. After using laser lithotripsy to fragment the overlying renal stone, a Weck Hem-o-lok clip was found to be embedded in the collecting system. A laser fiber through a flexible ureteroscope was used to successfully dislodge the clip from the renal parenchyma, and a stone basket was used to extract the clip. 1. Introduction Renorrhaphy is a time-sensitive and technically challenging aspect of robot-assisted partial nephrectomy (RPN). As such, the sutures used for kidney closure are commonly secured in place with a surgical clip [1], rather than conventional knot tying. A rare postoperative complication associated with this technique is migration of the surgical clip into the urinary tract, which may cause significant morbidity for patients [2–4]. Herein, we describe a case in which a Weck Hem-o-lok clip (Teleflex, Research Triangle Park, USA) migrated into the collecting system and acted as a nidus for stone formation after RPN. 2. Case Report A 52-year-old man with a history of nephrolithiasis and prostate cancer after robot-assisted radical prostatectomy presented with a small left renal mass. Abdominal computed tomography (CT) scan with and without contrast showed an enhancing 3 centimeter (cm) left middle pole renal mass that was noted to have increased in size since a prior CT scan. Subsequently, the patient underwent an uneventful left RPN. The renorrhaphy was completed in a single layer using a running 3-0 Vicryl (Ethicon, Somerville, USA) suture which was secured in place with Weck Hem-o-lok clips using sliding clip technique. Hemostasis was achieved without the use of any hemostatic agents or bolsters. The patient’s postoperative course was complicated by a perinephric hematoma that was diagnosed by CT scan. Renal angiography was negative for active bleeding, and the patient was managed with blood transfusions and close observation in the intensive care unit. Pathology indicated a 2.4?cm clear cell renal cell carcinoma, Fuhrman grade II, and negative surgical margins. Two years after RPN, the patient presented with left-sided colicky flank pain. Noncontrast helical abdominal CT scan showed a 6 millimeter (mm) left ureteral stone and a 10?mm left middle pole
Characterization of the Emergence of Order in an Oscillated Granular Layer
Daniel I. Goldman,Gemunu H. Gunaratne,M. D. Shattuck,Donald J. Kouri,David K. Hoffman,D. S. Zhang,Harry L. Swinney
Physics , 2000,
Abstract: The formation of textured patterns has been predicted to occur in two stages. The first is an early time, domain-forming stage with dynamics characterized by a disorder function $\bar\delta (\beta) \sim t^{-\sigma_{E}}$, with $\sigma_{E} = {1/2}\beta$; this decay is universal. Coarsening of domains occurs in the second stage, in which $\bar\delta (\beta) \sim t^{-\sigma_{L}}$, where $\sigma_{L}$ is a nonlinear function of $\beta$ whose form is system and model dependent. Our experiments on a vertically oscillated granular layer are in accord with theory, yielding $\sigma_{E}\approx 0.5\beta$, and $\sigma_{L}$ a nonlinear function of $\beta$.
Taxonomic Significance of Foliar Epidermal Characters in Azanza garckaena (F. Hoffm.) Exell & Hillc in Tula, Kaltungo Local Government Area of Gombe State, Nigeria  [PDF]
H. M. Abba, H. Daniel, S. Sale, D. A. Zhigila
American Journal of Plant Sciences (AJPS) , 2018, DOI: 10.4236/ajps.2018.98121
Abstract: Leaf epidermal microscopy of Azanza garckeana was studied in search of stable taxonomic characters and delimitation of the plant. Fresh leaves were obtained from 3 accessions in Tula: Tula Wange, Tula Baule and Tula Yiri/Bwaile respectively. Leaf epidermal peels of both surfaces of the plant were made using free hand sectioning and maceration methods. Temporary slides were prepared for observations under light microscope to examine their stomatal features, epidermal cell shapes, and anticlinal cell-wall patterns. The result revealed epiamphistomatic leaves, Stomatal complex type (SCT) was exclusively anomocytic, epidermal cell shapes were all irregular in shape, with curved anticlinal cell wall
Inflammation, Coagulation and Cardiovascular Disease in HIV-Infected Individuals
Daniel A. Duprez, Jacqueline Neuhaus, Lewis H. Kuller, Russell Tracy, Waldo Belloso, Stephane De Wit, Fraser Drummond, H. Clifford Lane, Bruno Ledergerber, Jens Lundgren, Daniel Nixon, Nicholas I. Paton, Ronald J. Prineas, James D. Neaton 1 for the INSIGHT SMART Study Group
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0044454
Abstract: Background The SMART study was a trial of intermittent use of antiretroviral therapy (ART) (drug conservation [DC]) versus continuous use of ART (viral suppression [VS]) as a strategy to reduce toxicities, including cardiovascular disease (CVD) risk. We studied the predictive value of high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6) and D-dimer with CVD morbidity and mortality in HIV-infected patients who were enrolled in SMART beyond other measured CVD risk factors. Methods A blood sample was available in 5098 participants who were enrolled in the SMART study for the measurement of IL-6, hsCRP and D-dimer. Hazard ratios (HR) with 95% CI for CVD events were estimated for each quartile (Q) for each biomarker vs the 1st quartile and for 1 SD higher levels. For both treatment groups combined, unadjusted and adjusted HRs were determined using Cox regression models. Results There were 252 participants who had a CVD event over a median follow-up of 29 months. Adjusted HRs (95% CI) for CVD for Q4 vs Q1 were 4.65 (2.61, 8.29), 2.10 (1.40, 3.16), and 2.14 (1.38, 3.33) for IL-6, hsCRP and D-dimer, respectively. Associations were similar for the DC and VS treatment groups (interaction p-values were >0.30). The addition of the three biomarkers to a model that included baseline covariates significantly improved model fit (p<0.001). Area under the curve (AUC) estimates improved with inclusion of the three biomarkers in a model that included baseline covariates corresponding to other CVD risk factors and HIV factors (0.741 to 0.771; p<0.001 for difference). Conclusions In HIV-infected individuals, IL-6, hsCRP and D-dimer are associated with an increased risk of CVD independent of other CVD risk factors. Further research is needed to determine whether these biomarkers can be used to improve CVD risk prediction among HIV positive individuals.
Epigenetic Subgroups of Esophageal and Gastric Adenocarcinoma with Differential GATA5 DNA Methylation Associated with Clinical and Lifestyle Factors
Xinhui Wang, Gyeong Hoon Kang, Mihaela Campan, Daniel J. Weisenberger, Tiffany I. Long, Wendy Cozen, Leslie Bernstein, Anna H. Wu, Kimberly D. Siegmund, Darryl Shibata, Peter W. Laird
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0025985
Abstract: Background Adenocarcinomas located near the gastroesophageal junction have unclear etiology and are difficult to classify. We used DNA methylation analysis to identify subtype-specific markers and new subgroups of gastroesophageal adenocarcinomas, and studied their association with epidemiological risk factors and clinical outcomes. Methodology/Principal Findings We used logistic regression models and unsupervised hierarchical cluster analysis of 74 DNA methylation markers on 45 tumor samples (44 patients) of esophageal and gastric adenocarcinomas obtained from a population-based case-control study to uncover epigenetic markers and cluster groups of gastroesophageal adenocarcinomas. No distinct epigenetic differences were evident between subtypes of gastric and esophageal cancers. However, we identified two gastroesophageal adenocarcinoma subclusters based on DNA methylation profiles. Group membership was best predicted by GATA5 DNA methylation status. We analyzed the associations between these two epigenetic groups and exposure using logistic regression, and the associations with survival time using Cox regression in a larger set of 317 tumor samples (278 patients). There were more males with esophageal and gastric cardia cancers in Cluster Group 1 characterized by higher GATA5 DNA methylation values (all p<0.05). This group also showed associations of borderline statistical significance with having ever smoked (p-value = 0.07), high body mass index (p-value = 0.06), and symptoms of gastroesophageal reflux (p-value = 0.07). Subjects in cluster Group 1 showed better survival than those in Group 2 after adjusting for tumor differentiation grade, but this was not found to be independent of tumor stage. Conclusions/Significance DNA methylation profiling can be used in population-based studies to identify epigenetic subclasses of gastroesophageal adenocarcinomas and class-specific DNA methylation markers that can be linked to epidemiological data and clinical outcome. Two new epigenetic subgroups of gastroesophageal adenocarcinomas were identified that differ to some extent in their survival rates, risk factors of exposure, and GATA5 DNA methylation.
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