bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cytotoxic and Anti-cancer Effects of Nickel Nanowires against Pancreatic Cancer Cells
Authors: Hossain Md. Zakir , Khudhayer Wisam J. , Akter Rozina , Karabacak Tansel , Kleve Maurice G. 
Published: November 2012

ABSTRACTCytotoxicity study of magnetic nanomaterials is a key consideration for biomedical applications. Very little is known about the cytotoxic and anti-cancer effects of nickel nanowires (Ni NWs) on mammalian cells and their interaction with proliferating cancer cells. Current therapeutics do not address the full heterogeneity of pancreatic cancers due to the resistance to apoptosis and does not suffice for a successful treatment. Therefore, synthesis of novel anticancer drugs continues to be a potential topic for pancreatic cancer research. In this study, we have investigated the cellular toxicity and anti-cancer effects of Ni NWs in one of the most aggressive human pancreatic ductal cancer (Panc-1) cell lines with the objective of development of a potential treatment strategy. Ni NWs were fabricated in a custom-made setup utilizing the electrodeposition method. Elemental analysis, crystallographic structure, and morphological properties of the synthesized Ni NWs were investigated using Energy Dispersive X-ray Analysis (EDAX), X-Ray Diffraction (X-RD) and Scanning Electron Microscopy (SEM), respectively. Panc-1 cell cultures were maintained according to a slightly modified American Type Culture Collection (ATCC) protocol. Morphological apoptogenic characteristics assessment of the Ni NWs induced Panc-1 cell was accomplished using phase contrast microscopy (PCM). Two commercially available cytotoxicity procedures including 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) and trypan blue (TB) assays were utilized to determine the qualitative and quantitative cytotoxicity and anti-cancer effects of Ni NWs. As a negative control, Panc-1 cells without Ni NWs treatment were used in all experiments. Phase contrast microscopy (PCM) was used to confirm the Ni NWs internalization by Panc-1 cells. Both the MTT and TB assays, qualitatively and quantitatively confirmed the cytotoxic and anti-cancer effects of Ni NWs treated Panc-1 cells in vitro in both concentration and exposure-time dependent manners. We studied the cytotoxic and anti-cancer effects of Ni NWs on Panc-1 cells using novel integrated bionanotechnological approaches to understand the corresponding biological pathway with the objective of developing pancreatic cancer treatment. More specifically, we explored the molecular mechanisms associated with the pathway involved in Ni NWs induced toxicity against Panc-1 cells. Our results demonstrated that Ni NWs show strong candidacy for targeting cell selective applications in pancreatic cancer therapy. Key words: Nickel Nanowires, anti-cancer effects, pancreatic cancer.
Thermal Gelation and Stability of Pectin Grafted with PEPE
Authors: Santan Harshal D. , Neffe Axel T. , Kamlage Stefan , Lendlein Andreas 
Published: November 2012

ABSTRACTStimuli-sensitive materials can change properties upon exposure to an external stimulus. Thermoreversible gelation upon heating is one example for such a stimuli sensitivity. Here, it is of significance to tailor the transition temperature and to achieve large changes of G’ and the viscosity. Grafting of the thermosensitive poly(ethylene glycol-b-propylene glycol-b-ethylene glycol)s (PEPEs) to pectin was performed in order to investigate if tailoring of the sol-gel-transition temperature can be achieved by adjusting the grafting ratio. PEPEs were aminated and grafted to the polysaccharide via EDC coupling as shown by FTIR. The sol-gel transition of the pectin, PEPE, and the grafted system (PGP) was investigated by rheology. The gelation temperature (Tgel) of the system could be adjusted by varying the grafting density of PEPE onto pectin as well as by the concentration of the thermosensitive polymer in aqueous solution. A concentration of 15 – 20 wt% of the grafted system in water led to gelation temperatures in the range of 25 – 33 °C and the critical micelle concentration (CMC) and critical micelle temperature (CMT) of the grafted systems were determined by UV spectroscopy. The viscosity and the G’ increased by four orders of magnitudes at Tgel, which is comparable to PEPEs alone, but could be reached at lower PEPE concentrations. In the future, a thorough mechanistic investigation of the gelation process would be of interest.
Tribological Properties of Graphene and Boron-Nitride Layers: A Fully Atomistic Molecular Dynamics Study
Authors: dos Santos Ricardo P. , Machado Leonardo D. , Legoas Sergio B. , Galvao Douglas S. 
Published: November 2012

ABSTRACTGraphene has been one of the most important subjects in materials science in the last years. Recently, the frictional characteristics of atomically thin sheets were experimentally investigated using atomic force microscopy (AFM). A new mechanism to explain the enhanced friction for these materials, based on elastic compliance has been proposed. Here, we have investigated the tribological properties of graphene and boron-nitride (single and multi-layers) membranes using fully atomistic molecular dynamics simulations. These simulations were carried out using classical force fields, as implemented in the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) code. The used structural models contain typically hundreds of thousands of atoms. In order to mimic the experimental conditions, an artificial AFM tip was moved over the membranes and the tribological characteristics determined in terms of forces and energies. Our results are in good agreement with the available experimental data. They show that the observed enhanced tribological properties can be explained in terms of out-of-plane geometrical distortions and elastic waves propagation. They validate the general features of the model proposed by Lee et al. (Science 328, 76 (2010).
Diffusion-bonded CNT carpets for fundamental CDI studies
Authors: Enright R. , Mitchell R. , Mutha H. , Lv C. , Christiansen M. , Thompson C. V. , Wang E. N. 
Published: November 2012

ABSTRACTUncertainty about future energy and water supplies suggests a pressing need to develop efficient technologies for water desalination. Capacitive deionization (CDI), a method that captures ions in the electrical double layer (EDL) of an electrochemical capacitor, is a promising technology that can potentially fulfill those requirements. Similar to supercapacitors, ideal CDI electrodes should have a large electrolyte-accessible specific surface area available for ion adsorption with rapid charging/discharging characteristics. Unlike supercapacitors, CDI electrodes are required to operate in aqueous electrolytes with low ionic concentrations in a non-linear charging regime. To explore this practically and theoretically important regime, we developed robust, electrochemically-compatible carbon nanotube (CNT) carpet electrodes that posses a well-defined and uniform pore structure that is more readily analyzed in comparison to the random and multi-scale pore structure of typical carbon electrodes. The fabricated electrodes were characterized using cyclic voltammetry and potentiostatic charging in aqueous NaCl solutions (no = 20 - 90 mM) using a three electrode setup. Examination of the CV and potentiostatically-measured capacitances were consistent with EDL behavior dictated by the Stern layer. However, some deviations from the expected behavior were observed with increasing salt concentration during potentiostatic testing.
Probing strain and microstrain in nanostructured thin layers.
Authors: Baldinozzi Gianguido , Simeone David , Gosset Dominique , Bérar Jean-Francois 
Published: November 2012

ABSTRACTThe analysis of the structures and microstructures of nanostructured thin layers can be performed using laboratory grazing incidence diffraction, provided accurate corrections are performed to handle the instrumental broadening effects related to the experiment geometry for an impinging beam close to the critical angle. Implementing these corrections in Rietveld refinement software allows the accurate extraction of quantitative relevant information about the structure (strain and atomic positions) and the microstructure (crystallite size and microstrain), selectively probing the material on a depth of few nanometers.
Morphology and Crystallinity Control of Novel Spider Silk-like Block Copolymer
Authors: Huang Wenwen , Krishnaji Sreevidhya , Kaplan David , Cebe Peggy 
Published: November 2012

ABSTRACTA new family of A-B di-block copolymers based on the amino acid sequences of Nephila clavipes major ampulate dragline spider silk, which have a strong potential for applications in tissue regeneration and drug delivery, was synthesized and characterized. The morphology was assessed by SEM: HBA3 formed fibrillar structure and 2 μm diameter hollow micelles, while HBA4 and HBA6 formed hollow micelles in water solution. The secondary structures of water-cast spider silk-like block copolymer films were assessed by FTIR. The crystallinity was determined by Fourier self-deconvolution of the amide I spectra and confirmed by wide angle X-ray diffraction. Results indicate that the self-assembled morphology and the crystallinity can be varied by changing the length of A-block, and a minimum of 3 A-blocks are required to form β sheet crystalline regions in water-cast spider silk block copolymers. A theoretical model was used to predict the specific reversing heat capacity, Cp(T), which is crucial to the design of smart biomaterials. Excellent agreement was found between the theoretical value and the Cp(T) determined by temperature modulated differential scanning calorimetry. This method can serve as a standard by which to assess the thermal properties for other biologically inspired block copolymers, and then be further applied to control the biological interactions for use in drug delivery and smart biomaterials applications.
Biomimetic Mineral-Protein Composites formed by an Automated Alternate Soaking Process
Authors: Armitage Oliver E. , Strange Daniel G.T. , Oyen Michelle L. 
Published: November 2012

ABSTRACTBiomineralized composite materials found in nature have a compromise of good mechanical properties and relatively small embodied energies in the process of their formation. The Alternate Soaking Process (ASP) is a laboratory technique that has only recently been applied to replicating composite biomineralization. The nexus of the ASP – heterogeneous nucleation – makes it ideal for replicating biominerals where the mineral is templated onto an organic substrate, such as occurs in avian eggshell. Here we demonstrate the deposition of a calcium carbonate gelatin composite on either glass cover slips or demineralized eggshell membranes using an automated ASP. SEM images and FTIR spectra of the resulting mineral show that by altering the amount of gelatin in the growth solutions the final organic component can be controlled accurately in the range of 1-10%, similar to that of natural eggshell. This study shows for the first time the co-precipitation of a CaCO3 – gelatin composite by an ASP and that the organic fraction of this mineral can be tuned to mimic that of natural biomineralized composites.
MMSSC Chemotaxis near Porous Surface of Biocompatible NiTi Scaffolds Synthesized by Selective Laser Sintering (SLS)
Authors: Shishkovsky Igor V. , Volchkov Stanislav E. , Tumina Olga V. 
Published: November 2012

ABSTRACTMultipotential mesenchymal stromal stem cells (MMSSC) are an excellent model for testing of the toxicity and biocompatibility of natural-tissue-engineering scaffolds (extracellular matrix). Such studies allow prediction of the behavior of implanted materials in the human. In the present work, testing of a three-dimensional prototype of a smart material – nitinol (the intermetallic phase NiTi) – to evaluate chemotaxis and biocompatibility was conducted.Porous samples were synthesized by the selective laser sintering (SLS) method, establishing different surface conditions in the samples. The surface microstructure and roughness were observed by scanning electron microscopy (SEM) and optical microscopy. The results revealed the clear influence of the surface roughness on stem cell proliferation, morphology, and adhesion. The NiTi samples were well tolerated by the cells but the number of focal contacts decreased with increasing porosity. The proliferation speed was 0.694 doubling/day in the control group and 0.532 doubling/day for the NiTi group. Whereas the control group showed immature and actively divided stem cells, cell growth to enormous sizes (i.e., rapid aging) and a fall in fission activity in the proximity of an external irritant (viz., the NiTi scaffold) was observed.
Numerical Simulation of SOFC Electrode Polarization Using Three-Dimensional Microstructure Reconstructed by FIB-SEM
Authors: Shikazono Naoki , Kasagi Nobuhide 
Published: November 2012

ABSTRACTThree-dimensional numerical simulations can provide information which cannot be obtained from experiments and can be a powerful tool for investigating reaction phenomena in solid oxide fuel cell (SOFC) electrodes. In the present study, a dual-beam focused ion beamscanning electron microscope is used to reconstruct the three dimensional microstructures of the SOFC electrodes, and their polarization characteristics are predicted by a lattice Boltzmann method. Predicted overpotentials for Ni-YSZ anode and mixed ionic and electronic conducting cathode (La0.6Sr0.4Co0.2Fe0.8O3-δ; LSCF6428) are compared with the experimental data for validation. In addition, three-dimensional distributions of electrochemical potential and current densities inside the electrode microstructures are obtained. Large non-uniformities of potential and current distributions are found in the Ni-YSZ anode, while those became much uniform in the LSCF cathode. The present method can be expected as a powerful tool for investigating local potential fields which affect local reactions and diffusion processes as well as local physical properties of the SOFC electrodes.
Fibroblast Growth Factor 21 Levels in Young Healthy Females Display Day and Night Variations and Are Increased in Response to Short-Term Energy Deprivation Through a Leptin-Independent Pathway
Authors: Foo Joo-Pin , Aronis Konstantinos N. , Chamberland John P. , Paruthi Jason , Moon Hyun-Seuk , Mantzoros Christos S. 
Published: November 2012

OBJECTIVE
Fibroblast growth factor (FGF)-21 is an endocrine factor with potent metabolic effects. Its day–night patterns of secretion and/or its physiological response to energy deprivation and relationship to free fatty acids (FFAs) and/or leptin remain to be fully elucidated. We aim to elucidate day–night pattern of FGF-21 levels and its relationship to FFA, to assess whether energy deprivation alters its circulating patterns, and to examine whether leptin may mediate these changes.

RESEARCH DESIGN AND METHODS
Six healthy lean females were studied for 72 h in a cross-over interventional study under three different conditions: on isocaloric diet and in a fasting state with administration of either placebo or metreleptin in physiological replacement doses. Blood samples were obtained hourly from 8:00 a.m. on day 4 until 8:00 a.m. on day 5.

RESULTS
FGF-21 exhibited day–night variation pattern during the isocaloric fed state. Fasting significantly increased FGF-21 levels (P &lt; 0.01) via a leptin-independent pathway. Day–night variation pattern in the fed state was lost on fasting. Leptin replacement in the hypoleptinemic state restored approximate entropy of FGF-21 time series but did not alter circulating levels. FGF-21 levels were closely cross-correlated with FFA levels in all three states.

CONCLUSIONS
A day–night variation in the levels of FGF-21 exists in young lean females in the fed state. Energy deprivation increases FGF-21 levels via a leptin-independent pathway. The interaction between FGF-21 and starvation-induced lipolysis, as indicated by its close cross-correlations with FFA in both fed state and energy deprivation, needs to be studied further.
Assessment of Barriers to Improve Diabetes Management in Older Adults
Authors: Munshi Medha N. , Segal Alissa R. , Suhl Emmy , Ryan Courtney , Sternthal Adrianne , Giusti Judy , Lee Yishan , Fitzgerald Shane , Staum Elizabeth , Bonsignor Patricia , DesRochers Laura , McCartney Richard , Weinger Katie 
Published: November 2012

OBJECTIVE
To evaluate whether assessment of barriers to self-care and strategies to cope with these barriers in older adults with diabetes is superior to usual care with attention control. The American Diabetes Association guidelines recommend the assessment of age-specific barriers. However, the effect of such strategy on outcomes is unknown.

RESEARCH DESIGN AND METHODS
We randomized 100 subjects aged ≥69 years with poorly controlled diabetes (A1C &gt;8%) in two groups. A geriatric diabetes team assessed barriers and developed strategies to help patients cope with barriers for an intervention group. The control group received equal amounts of attention time. The active intervention was performed for the first 6 months, followed by a “no-contact” period. Outcome measures included A1C, Tinetti test, 6-min walk test (6MWT), self-care frequency, and diabetes-related distress.

RESULTS
We assessed 100 patients (age 75 ± 5 years, duration 21 ± 13 years, 68% type 2 diabetes, 89% on insulin) over 12 months. After the active period, A1C decreased by −0.45% in the intervention group vs. −0.31% in the control group. At 12 months, A1C decreased further in the intervention group by −0.21% vs. 0% in control group (linear mixed-model, P &lt; 0.03). The intervention group showed additional benefits in scores on measures of self-care (Self-Care Inventory-R), gait and balance (Tinetti), and endurance (6MWT) compared with the control group. Diabetes-related distress improved in both groups.

CONCLUSIONS
Only attention between clinic visits lowers diabetes-related distress in older adults. However, communication with an educator cognizant of patients’ barriers improves glycemic control and self-care frequency, maintains functionality, and lowers distress in this population.
Pulse perturbation technique for determination of piroxicam in pharmaceuticals using an oscillatory reaction system
Authors: Pejić Nataša , Sarap Nataša , Maksimović Jelena , Anić Slobodan , Kolar-Anić Ljiljana 
Published: November 2012

Abstract
A simple and reliable novel kinetic method for the determination of piroxicam (PX) was proposed and validated. For quantitative determination of PX, the Bray-Liebhafsky (BL) oscillatory reaction was used in a stable non-equilibrium stationary state close to the bifurcation point. Under the optimized reaction conditions (T = 55.0°C, [H2SO4]0 = 7.60×10−2 mol L−1, [KIO3]0 = 5.90×10−2 mol L−1, [H2O2]0 = 1.50×10−1 mol L−1 and j 0 = 2.95×10−2 min−1), the linear relationship between maximal potential shift ΔE m , and PX concentration was obtained in the concentration range 11.2–480.5 µg mL−1 with a detection limit of 9.9 µg mL−1. The method had a rather good sample throughput of 25 samples h−1 with a precision RSD = 4.7% as well as recoveries RCV ≤ 104.4%. Applicability of the proposed method to the direct determination of piroxicam in different pharmaceutical formulations (tablets, ampoules and gel) was demonstrated.
A comparison of fluorescein and deuterated water as tracers for determination of constructed wetland retention time
Authors: Holcová Veronika , Šíma Jan , Dušek Jiří 
Published: November 2012

Abstract
Retention time of treated water in a horizontal subsurface flow constructed wetland was determined in the non-vegetative period using fluorescein and deuterium oxide. Fluorescein served as one of the most frequent tracers detectable at extremely low concentrations by fluorimetry; however, deuterated water (concentrations of deuterium measured by IRMS and expressed as δ (‰) against VSMOW) was used to precisely simulate the treated water flow movement. Tracer retention time (TRT) of fluorescein was 194 h while deuterated water TRT was 192 h. TRT and nominal hydraulic retention time (nHRT, 190 h) were nearly exactly equal. The tracer behavior of deuterated water was almost ideal. On the other hand, the fluorescein movement through the system was slightly influenced by the interaction with the vegetation bed (sorption causing the tailing of tracer-response curves). Nevertheless, both tracers can be successfully used and provide similar results. Retention time is a very important characteristic of a constructed wetland. It is closely connected with the efficiency of the contaminant removal from treated water. It has to be determined correctly when wetland operation parameters are optimized. The choice of the suitable and reliable tracer is always necessary. Fluorescein takes preference with respect to its simple and inexpensive determination.
Mechanical, thermal and surface properties of polyacrylamide/dextran semi-interpenetrating network hydrogels tuned by the synthesis temperature
Authors: Dinu Maria , Cazacu Maria , Drăgan Ecaterina 
Published: November 2012

Abstract
The mechanical, rheological, thermal, and surface behaviors of three polyacrylamide/dextran (PAAm/Dx) semi-interpenetrating polymer network (semi-IPN) hydrogels, prepared at 22°C, 5°C and −18°C, were investigated. The results were compared with those obtained on cross-linked PAAm without Dx synthesized under the same conditions. Hydrogels prepared at the lowest temperature were the most mechanically stable. The thermal stability of the semi-IPN hydrogels is slightly lower than the corresponding PAAm gels, irrespective of preparation temperature. The water vapor sorption capacity depended on the presence of Dx as well as preparation temperature, which determines the network morphology.
Rapid flow injection electrochemical detection of 3,3′,4,4′ tetrachlorobiphenyl using stabilized lipid membranes with incorporated sheep antibody
Authors: Nikolelis Dimitrios , Psaroudakis Nikolas , Michaloliakos Antonis , Nikoleli Georgia-Paraskevi , Scoullos Michael 
Published: November 2012

Abstract
An electrochemical biosensor based on a supported polymerized lipid film with incorporated sheep anti-3,3′,4,4′ tetrachlorobiphenyl (PCB congener 77) antibody using flow injection analysis was developed. The polymerized lipid film contained 85% (w/w) dipalmitoylphosphatidylcholine (DPPC) and 15% (w/w) dipalmitoylphosphatidic acid (DPPA), methacrylic acid, ethylene glycol dimethacrylate, AIBN and sheep anti-congener 77 antiserum. Congener 77 was injected into flowing carrier electrolyte and the flow stopped to detect the antigen. These membranes gave only a single transient proportional to log [congener 77] from 10−8 to 10−5 M, with a detection limit of ca. 10−8 M. A membrane containing 35% (w/w) DPPA was used to examine regeneration. The maximum number of cycles was about 5.
Electrode processes of selected redox active substances on poly(o-aminophenol) film electrode
Authors: Marczewska Barbara , Przegaliński Marek 
Published: November 2012

Abstract
Using the method of cyclic voltammetry, the electrode process of Ni2+, Pb2+, Cu2+ and pyrocatechin on a poly(o-aminophenol) (PoAP) modified glassy carbon electrode (GCE) was investigated. The PoAP polymer was found to affect the redox process of copper and pyrocatechin. The use of polymer of different thicknesses showed that the obtained film has a dense, nonporous structure. The redox process of the examined substances may be considered as proceeding on the polymer surface. The PoAP polymer obtained in the described conditions takes part in charge transfer.